Autoimmunity, Allergies and Basic Triplets

Basic Triplets Only in Primate Forms and Allergens

I have examined the proteins, autoantigens, that are the focus of a dozen autoimmune diseases and a similar number of allergens. All of these proteins have basic triplets that I previously associated with heparin-binding. I have had two recent revelations. First, these triplets appear to not be involved with heparan sulfate proteoglycans for internalization. In fact, HSPGs don’t appear to be involved, even though the process is inhibited by heparin. So this suggests a transport system, perhaps using the LDL receptor or the mannose-6-phosphate receptor, (or a protein with an acidic triplet or quartet.)

The second interesting observation is that the mouse, cat, dog, etc. versions of the human autoantigens lack the basic triplets. This suggests that these diseases cannot occur in non-primates by the same mechanisms. So what is the role of these basic triplets in humans? They didn’t evolve to cause problems under unusual conditions of chronic inflammation, so what is their adaptive advantage?

I think that the answers to these questions could yield the identification of a fundamental cellular transport process and associated cellular phenomena that could be worth a Nobel prize in medicine and it could be unravelled by a group of high school kids doing some straightforward bioinformatics.

Oh. I just remembered that IL-1 beta, the inflammatory cytokine, has a basic triplet. I just checked NCBI, and that basic triplet is found in all of the mammalian IL-1 betas. Oddly, the soluble receptor for IL-1 beta has an acidic quartet. I looked up the protein structure of the IL-1 beta bound to the IL-1 receptor and did a quick illustration using Chimera:

I put the surface on the IL-1 beta and left the IL-1R wrapping around it in as a ribbon. The basic triplet of IL-1 beta is in blue and the acidic quartet of the receptor is in red. One of the basic amino acids is stabilized by hydrophobic bonding over the face of a tyrosine, in yellow. Clearly, there is a simple ionic, plus-minus charge, bonding between the basic and acid amino acids. I don’t normally see this interaction between basic heparin-binding domains and other proteins. Other proteins that bind to heparin-binding domains use aromatic amino acids to make hydrophobic bonds with the hydrophobic arms of the basic amino acids, e.g. importin and nuclear localization signals or tryptophan/arginine ladders. The use of simple acid-base connections (with the projection of each stiffened by adjacent prolines) shows that this interaction is selected to be irreversible.

I don’t know all of the ramifications of basic triplets, but they are very important and are the basis for most modern allergic and autoimmune diseases.

Peanut Allergy Cause and Cure

--- the other 200 posts---

Summary:  The cure for peanut allergy should follow naturally from knowledge of the cause.  Since most allergies and autoimmune diseases result from the combination of 1) inflammation, 2) breakdown of immunological tolerance and 3) presentation of a primary immunogen, it follows that some types of peanut allergy are based on a continued problem with immune tolerance and fixing that defect should eliminate an allergic response to peanuts.  The current cure to resurrect immune tolerance is by enhancing regulatory T cells (Tregs) in the gut using resistant starch to improve the growth of Clostridia in the gut.

Peanut allergies are dangerous and this post does not advocate any medical treatments, but rather attempts to explain the cause and cures of allergies.

Just Treat the Immunological Tolerance Problem Instead of Mast Cells

Most people in fear of anaphylaxis from peanut dust, just try desperately to avoid peanuts in any guise.  That avoids the problem, but why not cure the allergy?  Recent research shows that peanut allergens can be prevented from establishing an allergic response in mice by addition of Clostridium species of bacteria in the gut flora.  It was shown that the Clostridia increased Tregs (regulatory T cells responsible for immune tolerance) in the lining of the intestines via interleukin 22 production.  So the cure to some peanut allergies may be increasing Tregs and fixing tolerance.

I Said It All Before

It is not a large step to combine my previous posts covering potato resistant starch for treatment of deficiencies of immunological tolerance with my explanation of the cause of allergies and autoimmunity to provide a simple explanation of the cause and cure for some peanut allergies.

Peanut Allergen is a Typical Bean Storage Protein Except for the Basic Triplet

It is not difficult to find out why peanuts are allergenic.  I just went to the National Center for Biotechnology Information (NCBI) web site and queried the protein sequence databases for “peanut allergen.”  Here is the complete amino acid sequence (each of the 20 amino acids of the protein is assigned a letter) of the major peanut [Arachis hypogaea] allergen:

MMVKLSILVALLGALLVVASATRWDPDRGSRGSRWDAPSRGDDQCQRQLQRANLRPCEEHMRRRVEQEQEQEQDEYPYSRRGSRGRQPGESDENQEQRCCNELNRFQNNQRCMCQALQQILQNQSFWVPAGQEPVASDGEGAQELAPELRVQVTKPLRPL

The triplet of basic amino acids (R=arginine, K=lysine), RRR in this case, which is found in all allergens and autoantigens, is highlighted in red.  If you eat peanuts with an inflamed gut and you have wiped out your Clostridia and associated Tegs with antibiotics, you have a good chance of developing autoimmunity, as well as a peanut allergy.  The cause of allergies is that simple and the cure is equally simple.

Shellfish Allergy Shows the Relationship between Allergy and Autoimmunity

I ran across a list of other food allergens when I was checking up on peanuts.  Shellfish was listed as another of the big allergies.  I looked up “shellfish allergen” and ran into thousands of entries.  The first couple of dozen proteins lacked the characteristic basic triplet, so I had to step back and try to guess the most typical shellfish for first exposure, i.e. the primary immunogen.  All of the other shellfish allergens were various versions of the muscle protein, tropomyosin, so I looked up “shrimp allergen.”

MDAIKKKMQAMKLEKDNAMDRADTLEQQNKEANNRAEKSEEEVHNLQKRMQQLENDLDQVQESLLKANIQLVEKDKALSNAEGEVAALNRRIQLLEEDLERSEERLNTATTKLAEASQAADESERMRKVLENRSLSDEERMDALENQLKEARFLAEEADRKYDEVARKLAMVEADLERAEERAETGESKIVELEEELRVVGNNLKSLEVSEEKANQREEAYKEQIKTLTNKLKAAEARAEFAERSVQKLQKEVDRLEDELVNEKEKYKSITDELDQTFSELSGY

Note the predicted basic triplet in red.  Since I was on a roll, I also checked out related tropomyosin sequences in humans:

MDAIKKKMQMLKLDKENALDRAEQAEADKKAAEDRSKQLEDELVSLQKKLKGTEDELDKYSEALKDAQEKLELAEKKATDAEADVASLNRRIQLVEEELDRAQERLATALQKLEEAEKAADESERGMKVIESRAQKDEEKMEIQEIQLKEAKHIAEDADRKYEEVARKLVIIESDLERAEERAELSEGKCAELEEELKTVTNNLKSLEAQAEKYSQKEDRYEEEIKVLSDKLKEAETRAEFAERSVTKLEKSIDDLEDELYAQKLKYKAISEELDHALNDMTSM

Once again the basic triplet indicated that there was a related human tropomyosin that could interact with antibodies to the shellfish allergen or could be an autoantigen participating in autoimmune diseases.  So I checked PubMed for “tropomyosin autoantigen” and quickly found that antibodies to tropomyosin are important in ulcerative colitis (UC).  Thus, shellfish allergy may be an indication of an underlying predisposition to UC.  And, the traditional cure for allergy by injection with small amounts of the allergen to convert from IgE to IgG, would convert a shellfish allergy into UC.

Avoiding Allergens Makes No More Sense Than Trying to Avoid Autoantigens

To fix allergies, it is necessary to eliminate the cause and block perpetuation of the condition.  The cause is based on 1)inflammation, 2) broken immune tolerance and 3) primary immunogen.  Peanuts are the primary immunogen, but that is unimportant if the causing conditions are eliminated and tolerance is reestablished.  Clearly, if immunological tolerance is reestablished, then it's just a matter of time before peanuts are no longer a problem, because increasing Tregs will silence the dramatic immunological response to peanuts.  Tolerance is based on Tregs and Tregs develop in the intestines in response to Clostridia feeding on soluble fiber/resistant starch.

Curing Peanut Allergies is Based on Repairing Gut Flora

There are a couple of hundred different species in the pounds of bacteria in the healthy human gut.  Most of those bacteria require soluble fiber that is systematically removed during food processing.  For most people, the cure for peanut allergies will be resistant starch/Clostridium therapy, followed by further repair with fermented foods that provide the typical lactic acid bacteria and soluble fiber along with companion bacteria that can recolonize the gut.  The cure for many allergies and autoimmune diseases is just to eat a couple of tablespoons of resistant starch each day and if needed, supplement with probiotics containing Clostridium butyricum.  If there is severe dysbiosis, as indicated by constipation, then fixing the gut flora is a little more difficult, but for most people cures are much cheaper and effective than just treating symptoms.

A guide for the use of resistant starch is provided by Richard Nikoley, et al. at Free the Animal.

Arthritis, Autoimmunity and Arginine Deimidation

Celiac and Antibody Production Against Tissue Transglutaminase as a Model

Arthritis is an autoimmune disease in which the immune system attacks and degrades the connective tissue of joints.  Antibodies against modified amino acids, arginine converted to citrulline, and proteins commonly found in joints, mediate the arthritis disease process.  The development of arthritis mimics the development of gluten intolerance, celiac, in which another enzyme, transglutaminase ( tissue transglutaminase, tTG or TG2) modifies the major gluten protein, gliadin, and antibodies are produced against both modified gliadin and TG2 autoantigen.

Arthritis of Joints Is Like Coeliac of Intestines;  Autoantibodies to Protein Modifying Enzymes

In other articles, I outlined the pathology of gluten intolerance:

• The major protein of wheat gluten, gliadin, contains long stretches of glutamines.
• An intestinal enzyme, TG2, converts the glutamines to glutamates by deamination.
• As TG2 works it binds to gliadin.
• In celiac, the TG2-gliadin complexes are internalized and fragmented to stimulate antibody production against both TG2 and gliadin.
• I think that the internalization and processing for antibody stimulation is dependent on the basic triplet found in TG2.

Arthritis Is Mediated by Autoantibodies to Peptidylarginine Deiminase and Citrullinated Proteins

Parallel to the celiac example, in some forms of arthritis, antibodies are produced against an enzyme that modifies proteins.  In arthritis, the enzyme involved, peptidylarginine deiminase (PAD) removes the terminal nitrogen from arginine (deimination) to produce citrullinated proteins.  Antibodies are produced to both PAD and citrullinated proteins.

PAD Also Has a Triplet of Basic Amino Acids for Internalization

I of course wondered if PAD had the same triplet of basic amino acids, e.g. RRK, that I had found on all other autoantigens and allergens.  Examining the sequence of human PAD in the NCBI sequence databases and comparing to other sequences, I found the basic triplet near the carboxy terminus.  The same or an alternative basic triplet was found in PADs from other mammals.

Autoantigens and Predicted Basic Triplets of Amino Acids Reveal the Cause of Arthritis

Arthritis is an inflammatory disease.  That means that without inflammation, arthritis cannot start and if inflammation is inhibited, arthritis cannot progress.  It is likely that arthritis is the result of chronic inflammation plus a precipitating event, such as joint injury or joint infection.  Alternatively, in a manner similar to Hashimoto’s thyroiditis, in which celiac produces anti-TG2 antibodies that attack the TG2 also produced in the thyroid gland, arthritis may be produced by autoantibodies stimulated in the inflammation of other tissues and spreading to the joints.  Celiac is also a risk factor for arthritis.  Trauma-based inflammation of a joint can also result in migration of Clamydia pneumonia (Cpn)-infected macrophages to the site of inflammation.  Cpn could contribute to joint inflammation and promote immunological presentation of autoantigens and autoantibody production.

reference:
Stenberg P, Roth B, Wollheim FA.  Peptidylarginine deiminases and the pathogenesis of rheumatoid arthritis: a reflection of the involvement of transglutaminase in coeliac disease.  Eur J Intern Med. 2009 Dec;20(8):749-55. Epub 2009 Sep 19.

The Cause of Allegies and Autoimmune Diseases

Keyhole Limpet Hemocyanin (KLH): Internalized Antigen

Scanning the literature for a common protein that can be used as an experimental antigen, it becomes quickly obvious that a favorite is KLH. This would seem to be an odd choice -- why a keyhole limpet protein? But that is the wrong question.

Why is KLH such a good antigen, i.e. why is it readily presented to the host immune system? If you have been reading my posts, you might be thinking about triplets of basic amino acids and that is the answer.

As soon as I remembered the prominent use of KLH as an antigen, I checked the NCBI protein database and immediately found an unusual KKK (triple lysine) near the amino terminus of hemocyanin II ( it comes in two pieces). This triplet explains why KLH is such a good experimental antigen, because it is internalized into antigen presenting cells by its strong heparin-binding domain. Other components, adjuvants, are typically added to the KLH for injection to make sure that a strong local inflammation occurs.

Autoantigens Have Strong Heparin-Binding Triplet

I also learned that Hashimoto’s thyroiditis is an autoimmune disease mediated by the autoantigen thyroid peroxidase. A quick search reveals that thyroid peroxidase is an autoantigen, because it also has a triplet of basic amino acids that can enhance presentation under inflammatory conditions. Grave’s disease of hyperthyroidism is an autoimmune disease in which the thyroid receptor (with a basic triplet) is an autoantigen. The same kind of triplet of basic amino acids was found when I searched today for fire ant antigens and mosquito antigens.

I have also looked for the triplets in protein databases. The triplets are rare in cytoplasmic and extracellular proteins. The proteins that have triplets are usually identified as autoantigens in some disease. The triplets are common in nuclear proteins, since heparin-binding and nucleic acid-binding share the same basic amino acid domains. The nuclear internalization signal also results in rapid cellular internalization, e.g. HIV-TAT, heparanase, IGF-binding proteins. Nuclear proteins are common autoantigens in lupus.

Inflammation Plus Heparin-Binding Internalization: Allergy, Autoimmunity

Chronic inflammation can produce antibodies against proteins (foreign or self) with strong heparin-binding domains (triplets or sometimes neighboring pairs of basic amino acids, lysine or arginine). The generalization explains why particular proteins in pollens, foods, insects, pets, mites, asthma, MS, lupus, celiac, etc. produce antibody responses.

An Autoantigen for Pancreatitis

Pancreatic Secretory Trypsin Inhibitor (PSTI) Has Internalization Basic Triplet

Pancreatitis is an inflammation of the pancreas resulting from lack of adequate inhibition of proteases. Autoantibodies against PSTI would explain some forms of pancreatitis.

I was researching the maintenance of baby gut flora by mother’s milk, when the reference discussed here was brought to my attention by my wife, who happens to be a lactation consultant. The paper showed that PSTI is present in colostrom, the first milk that a baby gets, before the true milk comes in. PSTI protects the new gut from digestion by its own pancreatic proteases, since PSTI is a protease inhibitor that sticks to the gut.

I naturally assumed that PSTI stuck to the gut by heparin-binding domains that would stick to the heparan sulfate proteoglycans on the gut surface. [Recall that it is via these HSPGs that viruses and bacteria infect the gut and the HSPGs in turn are protected during infections by the release of heparin from mast cells. The heparin in the guts of cattle and pigs are used to make commercial heparin to block blood clotting.] So I looked up the structure (above, with basic amino acids in blue and basic triplet on right) sequence of human PSTI at NCBI:

>gi|190694|gb|AAA36522.1| PSTI
MKVTGIFLLSALALLSLSGNTGADSLGREAKCYNELNGCTKIYD
PVCGTDGNTYPNECVLCFENRKRQTSILIQKSGPC

The basic triplet (RKR,arg-lys-arg), from my perspective, should result in presentation to the immune system during high levels of inflammation, and as a consequence result in autoantibodies against PSTI. The result would be the neutralization of the protease inhibitor and damaging production of active protease to attack the pancreas, i.e. pancreatitis.

It would be fairly easy to test this hypothesis by looking for the anti-PSTI antibodies in some people with pancreatitis. Other autoantibodies, e.g. against tissue transglutaminase, might also be checked, because the inflammation that produced one autoantibody may produce others and both PSTI and tTG are produced in the intestines. In fact, celiac may be the cause of some cases of autoimmune pancreatitis.

Note added in proof:

I just checked the literature on PubMed and found that PSTI is in fact an autoantigen in pancreatitis and produces antibodies against PSTI:
Raina A, Greer JB, Whitcomb DC. Serology in autoimmune pancreatitis. Minerva Gastroenterol Dietol. 2008 Dec;54(4):375-87.

and
I found that pancreatitis is often found associated with celiac (gluten intolerance):
Patel RS, Johlin FC Jr, Murray JA. Celiac disease and recurrent pancreatitis. Gastrointest Endosc. 1999 Dec;50(6):823-7.

ref:
Marchbank T, Weaver G, Nilsen-Hamilton M, Playford RJ. Pancreatic secretory trypsin inhibitor is a major motogenic and protective factor in human breast milk. Am J Physiol Gastrointest Liver Physiol. 2009 Apr;296(4):G697-703.

200th Post — Diet, Inflammation, Disease & Gut Flora

— all 200 Posts —

I started posting to Cooling Inflammation on 21 Aug, 2008 with How Your Diet Makes You Sick or Healthy.  My impetus for writing was my growing awareness that diet was the major reason why people were sick, and that health myths were preventing people from being healthy.  Inflammation originated by diet-inflicted injury and people attributed their sickness to genetics, environmental toxins and pervasive pathogens. 

My Path to the Obvious

My research background started with plant biochemistry, including carbohydrate structural analysis and polyphenol chemistry.  At that stage I was interested in understanding how plants protected (phytoalexins) themselves from pathogens, and I expected to use this perspective to explore human innate immunity.  From there, I went on to enzymology and protein characterization, biofilm structure, plant genetic engineering and breeding, monoclonal antibody production, mycotoxin detection, stem cell analysis, passive immunity in neonates, computational modeling of collagen and heparin binding, and heparan sulfate proteoglycan inhibition by inflammation.  These were temporary foci and the research imperatives, in retrospect, prevented me from seeing the bigger pictures, although they did leave me with a broad skill set.

Perspective: Water and Surface Tension

When I finally decided to slow down, smell the flowers and start having kids, I switched from research to teaching, from university to small liberal arts college.  For the first time, I actually thought about what I was teaching and my first revelation was that after teaching biochemistry for twenty years, I didn’t understand water and surface tension.  I could provide the platitudes from the Molecular Biology of the Cell, but I couldn’t do it mechanistically with colliding, sticky, energetic water molecules in my mind or at the blackboard.  I had to develop functional explanations of hydrogen bonds, entropy and thermal energy, that translated into the structuring of a layer of water molecules responsible for hydrophobic interactions and surface tension.  I extended that to include an explanation of the two layers of water holding together cytoplasmic membranes, the tube of structured water that holds together the cylinder of stacked bases in DNA or the shrink wrapping water layer surrounding proteins.

Perspective: Heparin Binding and Amphipathy of Sugars and Basic Amino Acids

As the kids got older, I started to dabble in research again and my expertise in carbohydrate chemistry led me into cartilage (mostly the glycosaminoglycan, GAG, chondroitin sulfate) synthesis and ultimately another GAG, heparan sulfate proteoglycans (HSPGs).  I was attracted to the dynamic HSPGs, that recycled with a half-life of six hours and formed layers around chondrocytes that secreted cartilage as they burrowed/ate through living cartilage.  I learned that the heparin filled granules of mast cells could be stained with berberine, which similarly stained the heparin in basement membranes of tissues and amyloids of Alzheimer’s, atherosclerosis and diabetes.  I was led by protein modeling of collagens to the binding of heparin to proteins and the revelation that basic amino acids (heparin binding domains) and sugars (heparin) are amphipathic, i.e. they have both hydrophobic and hydrophilic regions.  This is also true of plant polyphenolics.  Thus, polyphenolics, “basic” amino acids, “hydrophobic” amino acids, and sugars will all stack together.

Amphipathic Interactions

• DNA bases stack.
• Heparin binding sites of proteins are basic amino acids (Arg, Lys).
• Sugar binding sites in enzymes and lectins are hydrophobic amino acids (Trp, Tyr, Phe).
• Nuclear translocation signals, quartets of basic amino acids, bind to receptors with tryptophans.
• Tryptophans are the most highly conserved amino acids in the same proteins across great evolutionary distances.
• Hydrophobic bonding between tryptophan and a sugar or basic amino acid is ten times greater than hydrogen or ionic bonds.
• Tryptophan/Arginine ladders zip regions of proteins together.
• Polyphenols can disrupt cellular protein interactions by binding to receptors for carbohydrates/heparin, steroid hormones, amyloids, etc.
• Heparin holds dozens of hormones to receptors and changes the shapes of proteins, e.g. clotting and complement.
• Most nucleic acid binding proteins will also bind to the more negatively charged heparin.
• Bacteria use a pair of lysines to mark proteins for export.
• Peptides containing the basic amino acids of heparin binding domains (also produced by the specificity of gastric proteases) are antimicrobial, e.g. defensins, and so are plant polyphenols.
• Many drugs are active because they are domesticated plant polyphenols.

From Heparin Binding to Antigen Presentation

As soon as I realized that basic amino acids were involved in heparin binding, I started to look for the basic amino acids (R for arginine and K for lysine in amino acid sequences) in proteins known to bind heparin.  After study of hundreds of structures, it became obvious that heparin binding domains were simply a pair of basic amino acids (RR or KK or RK) with another within a distance of six amino acids.  No particular structure was necessary, as I later deduced, since binding to the heparin provided the structure.  In fact, in many X-ray crystallographic structures, the heparin binding regions on the surface of the protein are missing, because they are not in a defined shape.  I suspected that protein antigens involved in autoimmunity and allergy might be brought into cells for presentation to the immune system by interacting with HSPGs on the surface and so started to check them out for heparin binding domains.  I was very skillful at picking out pairs of Ks or Rs within sequences of hundreds of amino acids by that time, so I was shocked to see that the first dozen antigens that I checked, all had a triplet of basic amino acids.  I had discovered that autoantigens and allergens utilize a basic triplet analogous to the basic quartet used in nuclear translocation!  This also explained why proteins that interact with nucleic acids and are transported into the nucleus with a basic quartet are also prominent autoantigens.

Gut Flora and Immunity

Twenty years ago I read a curious description of leprosy that said that the course of infection could be either innocuous or devastating depending on whether the aggressive or the suppressive part of the immune system dominated.  I remained perplexed until I realized that diet and gut flora were the major determinants.  I was aware of the importance of diet at the outset of this blog, because it was clear that diet trumped genetics.  I was also aware thirty years ago in my studies of passive immunity, that milk contained bifidus factor, now known to be milk oligosaccharides, that controlled the growth of Lactobacilli that in turn controlled the development of the neonate immune system.  It was also known that bacteria-free mice had impaired immune systems.  It still took me several years for the relationship between diet, gut flora and immunity to make sense.  I began searching the literature for connections between gut flora and development of the immune system and soon noted experiments that linked filamentous bacteria with aggressive components and Clostridium spp. with Tregs.  A further refinement was linking resistant starch, a soluble fiber, with Clostridium.

My Current Views are Summarized in Three Health Diagrams

Diet, Gut Flora, Inflammation, Antigen Presentation, Tregs and Autoimmunity

Protein from the body and from food don’t normally stimulate the immune system, because there in no inflammation, the proteins lack basic triplets that enhance presentation, and antibody production and aggressive T cells are suppressed by Tregs.  Diet can throw the balance toward autoimmunity and allergy, by producing inflammation, e.g. hyperglycemia/AGE or high omega-6 fatty acids/prostaglandins, and starving gut flora needed for Treg production by eating processed food lacking soluble fiber.  The combination of inflammation and Treg deficiency causes proteins, either self or potential allergens, which have basic triplets to be presented to the immune system and stimulates attack by the immune system.

The Cure is to Cool Inflammation and Stimulate Tregs with Diet and Bacteria

I have provided an outline with The Anti-Inflammatory Diet to avoid inflammation, to stimulate existing gut flora with soluble fiber and encourage Treg production.  Mark Sisson, on Mark’s Daily Apple has provided an excellent dietary guide that also provides starch guidelines.  If you already have symptoms of autoimmune disease or allergies, then Richard Nikoley provides gut flora repair advice on Free the Animal, and Dr. B G provides more details on Animal Pharm.

Autoimmunity and allergies are not genetic destiny and they can be cured with diet and bacteria.

Watson Makes Us Sick

Common Textbook: Molecular Biology of the Cell, Lacks Coverage of Critical Molecular Interactions

One of the major reasons why healthcare practitioners are unable to cure diseases, is that their molecular view of disease is outdated. Their models of key signaling interactions lack critical molecules and fundamental types of chemical bonds are ignored.

The Major Textbook Used to Train Medical Students Lacks Essential Cellular Interactions

The most pervasive and perhaps the best text book on cell biology, The Molecular Biology of the Cell, first authored by James Watson, lacks a discussion of the bonding of aromatic amino acids (tryptophan, tyrosine, phenylalanine) with basic amino acids (arginine, lysine), carbohydrates, and aromatic phytochemicals, e.g. plant antioxidant or alkaloids. As a result, medical school graduates lack familiarity with the prominent interactions that dominate disease and drug treatments.

Hydrophobic Bonding to Aromatic Amino Acids Dominates Cell Molecular Biology

The dominating significance of aromatic hydrophobic bonds is the strength of these bonds, ca. 20 kcal/mol versus, the commonly considered weak bonds (hydrogen, ionic) at 1-2 kcal/mol, the same as the kinetic energy of water at body temperature. Thus, structures, such as alpha helices and beta sheets of proteins, require multiple weak bonds to be stable, but the hydrophobic bonding of tryptophan to a single arginine draped across its surface is stable.

Examples:

Tryptophan is the most highly conserved amino acid in protein structures (more than cysteine forming disulfide bonds!). This means that tryptophan is the most important amino acid in protein structure, and probably determines how proteins fold.

Carbohydrates have hydrophobic faces to their ring structures and typically bind to lectins, glycosidases and glycanases, via the hydrophobic surfaces of tryptophans or tyrosines in active sites.

Transport of proteins into nuclei is by binding of arginine or lysine residues of nuclear localization signals (basic quartets or neighboring basic pairs) to tryptophan hydrphobic residues projecting from the surface of LRR (leucine-rich repeat) importin molecules.

Heparin binds to basic amino acids in proteins via hydrophobic interactions. Aromatic dyes, such as berberine, bind to heparin through similar hydrophobic interactions.

Heparin binds to the basic amino acids arrayed in stacks of amyloid molecules and berberine blocks these interactions. Congo Red, a diagnostic dye for amyloids, is an aromatic molecule. Similar interactions occur with prions and the plaques of atherosclerosis.

Acidic polysaccharides form the matrix of biofilms. Heparin and nucleic acids can also serve this function. PEG, which disrupts hydrophobic interactions, can be used to disrupt binding of proteins to heparin, nucleic acids and biofilm polysaccharides.

Heparin binding mediates the interaction between most growth factors or cytokines and their cell surface receptors.

Many viruses and bacteria bind to cell surfaces via heparan sulfate.

LDL binds to LDL receptors via heparan sulfate. ApoE in diagram (arg and lys in blue, hydrophobic in pink.)

Antimicrobial peptides, e.g. defensins, have groups of basic amino acids. Heparin binding domains excised from proteins as peptides are antimicrobial.

Stomach proteases cleave around heparin-binding domains to produce antimicrobial peptides. Intestinal proteases cleave within heparin-binding domains and inactivate bacterial and viral agglutinins.

Life starts with heparin, i.e. heparin is leaked into fertilized eggs to remove the small, highly basic proteins used to package the sperm chromosomes.

Heparin is injected experimentally into nerves to silence IP3 signaling based on the binding of the hydrophobic face of inositol to basic amino acids, similar to heparin binding domains, of the IP3 receptors located on the surface of the ER.

The cytoplasmic domains of some receptor proteins have basic regions that interact with the IPs of the membrane surface, but subsequently serve to transport membrane-derived vesicles to the nucleus via importin carriers.

Heparin/heparan sulfate proteoglycans are secreted bound to basic molecules such as polyamines or histamine.

Heparan sulfate proteoglycans are continually secreted and taken up with a half life of six hours. This circulation is a major transport system of most cells. Amyloid/heparan aggregates on the surface of nerves and gliadin/tTG/antibody/heparan complexes on endocytes (celiac) may poison this system.

All allergens and autoantigens have a triplet of basic amino acids that may be involved in the initial aberrant presentation of these antigens as a result of the internalization by the carbohydrate-binding domain of mannose receptors on the surface of inflammation-stimulated immune cells.

Many neurotransmitters bind to their receptors via hydrophobic, aromatic interactions. These same receptors interact with hydrophobic, aromatic phytochemicals, e.g. “anti-oxidants.” Many spices, herbs, alkaloids and other phytochemicals have their abundantly complex interactions via these mechanisms.

Crystals of the tryptophan repressor involved in binding tryptophan and altering the expression of genes involved in tryptophan synthesis, shatter in the presence of tryptophan -- the tryptophan (yellow) strongly binds to basic amino acids (blue) in the tryptophan-binding domain of each repressor protein in the crystal and alters its shape.

Cause of Autoimmunity and Allergies

Inflammation-Induced Presentation by Mannose Receptor

Speculation on how innocuous proteins become the targets of our immune systems, and result in allergies, asthma, celiac, arthritis, lupus, and other inflammatory autoimmune diseases.

Inflammation

It all starts with chronic inflammation. In most cases diet is the predominant source of inflammation, but infections (bacterial, viral, fungal) may also contribute. Inflammation sets the stage for faulty processing of proteins at the focal location where lymphocytes and antigen-presenting cells are congregating.

Antigen Presentation

At this point a major mistake occurs. Cells that have been alerted to danger by inflammatory cytokines, start to internalize and process proteins in the vicinity, so that peptide fragments of the “antigens” can be displayed on their surfaces in the clutches of major histocompatibility complex proteins. The problem arises when self proteins are internalized, processed and displayed as candidate peptides.

Basic Triplets of All Allergens and Autoantigens

I have looked at dozens of allergens and autoantigens, and they all have one peptide sequence in common, a triplet of basic amino acids. The impetus for this article was finding this morning that one of the autoantigens for Hashimori’s thyroiditis is thyroglobulin, the serum carrier of thyroid hormones. I checked the sequence of thyroglobulin and it has two of the rare basic triplets.

Thyroiditis Autoantigen Is Thyroglobulin

I checked the Pubmed literature to see if thyroglobulin is naturally taken up by cells, since I have been trying to figure out the receptor for basic triplets. What I found was an article on the binding of thyroiditis autoantigens to mannose receptor. The idea of the paper was that the autoantigens in this case were heavily glycosylated and maybe the mannose receptor that is involved in antigen presentation of glycosylated antigens, would bind the selected autoantigens as well. I didn’t get much past the title of the paper.

Candidates for Allergen/Autoantigen Receptor

What I put together was the fact that antigen presenting cells use mannose receptor to internalize antigens. This places this receptor in the right place and the right time to be a receptor for basic triplets. But what would a basic triple binding protein domain look like and could mannose receptor be a candidate?

Structure of Thyroglobulin

I downloaded a structure for mannose receptor and began looking for a surface region that would bind carbohydrates, aromatics and basic amino acids. The critical amino acids in all of these cases are aromatic amino acids, phenylalanine, tyrosine and tryptophan. Tryptophan is at the heart of most carbohydrate binding proteins. Since the mannose receptor is a member of the carbohydrate-binding lectins, I expected to find tryptophans on the surface of the mannose receptor. I just looked for the tryptophan that binds the carbohydrates. It was exactly as I predicted. The mannose receptor should be able to form very stable tryptophan/arginine-like ladders with basic triplets.

I made a figure of the mannose receptor bound to a carbohydrate (red and grey). One of the exposed tryptophans (yellow) is bound to the carbohydrate. Several other tryptophans could be exposed and oriented toward a basic amino acid spread over the surface of the tryptophan in place of the carbohydrate. A similar kind of structure is used by importin to transport proteins with nuclear localization sites (NLS, basic quartets) into the nucleus. Many proteins with NLSs are also autoantigens, e.g. lupus.

I think that the peculiar circumstances that lead to allergy and autoimmunity result in the binding of self-proteins or allergens to mannose receptor and result in antibody production.

Why the Mannose Receptor?

Why does the mannose receptor make mistakes? The exposed tryptophan may also bind numerous plant products. In fact, the phytochemicals, e.g. alkaloids, flavonoids and terpenoids, are an abundant and varied group of chemicals that would bind to the exposed tryptophan of the mannose receptor and compete for binding with basic triplets. Protection offered by plant “anti-oxidants” may be due in part to this activity.

Insulin-like Growth Factor, Diabetes Autoantigen

IGF Binding to Heparin is Basis for Receptor Interaction, Internalization and Immunization

Examination of the protein sequence of insulin-like growth factors reveals strong heparin-binding domains (triplet of basic amino acids) that are also associated with internalization. Similar heparin internalization domains are also found on allergens and autoantigens. It was a small leap to expect that IGFs would also become autoantigens under inflammatory conditions that minimize heparan sulfate proteoglycan production.

Triplets of Basic Amino Acids Internalize Proteins

In several articles on this blog, I have discussed proteins that are internalized by their heparin binding domains. Heparin binding domains consistent only of a pair of basic amino acids, e.g. RK, flanked by one or more basic amino acids within a hydrophobic sequence of protein, are not sufficient to mediate internalization on heparan sulfate proteoglycans. A triplet of basic amino acids is usually required. Simple inspection of amino acid sequences is sufficient to identify these regions.

Internalization Triplet Identified in Insulin-like Growth Factor Binding Proteins

I noticed in a paper that insulin-like growth factors bind to epidermal growth factor receptors. I have previously written an article showing that EGF1 binds to its receptor via heparin, i.e. both the EGF and the receptor have heparin-binding domains. So I suspected that IGFs also had heparin binding domains. Inspection of the sequences readily identified simple heparin binding domains with pairs, but not triplets of basic amino acids. A search of the literature confirmed that heparin mediated IGF binding to receptors. A further search indicated that the heparin binding domains from proteins that bind and control the activity of IGFs could mediate internalization of proteins into cells and also into nuclei.

Internalization Triplets Are Associated with Allergens and Autoantigens

I have previously noted that all allergens and autoantigens have internalization triplets of basic amino acids. The presence of these triplets in IGF binding proteins suggested that IGF binding proteins might also be autoantigens. A quick check of the literature showed that antibodies against IGFs themselves frequently occur in type I diabetes. This suggests that the IGF-binding protein complexes are internalized and IGFs are immunologically presented during inflammation to produce anti-IGF antibodies. It is interesting that the other autoantigens for type I diabetes, e.g. transglutaminase, also have the expected internalization triplets.

references:
Maruyama T, Murayama H, Nagata A, Shimada A, Kasuga A, Saruta T.
Anti-insulin-like growth factor-1 autoantibodies in type 1 diabetes. Ann N Y Acad Sci. 2002 Apr;958:267-70.

Miao D, Yu L, Eisenbarth GS. Role of autoantibodies in type 1 diabetes. Front Biosci. 2007 Jan 1;12:1889-98.

Goda N, Tenno T, Inomata K, Shirakawa M, Tanaka T, Hiroaki H. Intracellular protein delivery activity of peptides derived from insulin-like growth factor binding proteins 3 and 5. Exp Cell Res. 2008 Aug 1;314(13):2352-61. Epub 2008 May 29.

Preventing Allergies

The cause of allergies and autoimmune degenerative diseases is inflammation.

As a scientist, I am concerned with how the body works at the molecular level. I try to understand how molecules of cells interact to cause disease. So if you tell me that you have an allergy, I want to understand how you became allergic and I am much less interested in how you avoid triggering your allergy. If you say that your allergy is triggered by ragweed pollen, I want to know the shape and structure of the proteins or carbohydrates of the pollen that actually come in contact with receptors on the surface of your cells and trigger the allergic response, but I also want to trace those interactions back to the original events that started the allergy.

Allergies are mistakes of your immune system. Your body should learn to ignore common food and environmental molecules as it ignores itself. There is an elaborate system used by cells of your body to disassemble and display fragments of dangerous pathogens on the surface of cells for evaluation by the immune system. Inappropriate display of innocuous or self molecules is part of the problem in allergies and autoimmunity.

Ragweed pollen, for example, will cause no reaction unless pollen proteins bind to antibodies (IgE) held in receptors on the surface of mast cells. We know that ragweed pollen binds to anti-ragweed antibodies on the surface of mast cells of allergic individuals and triggers the release of histamine and other molecules that give the symptoms of allergy. That’s why you take antihistamines to remediate the allergic symptoms. The first questions are what are the ragweed molecules to which the antibodies bind, i.e. the ragweed allergens and why is this allergic person producing anti-ragweed antibodies?

We know that the ragweed allergens are common pollen proteins, but why are they particularly prone to producing allergies? I tried to figure out this riddle by asking if there is something about these proteins that make their transport into cells more likely. I had just discovered that a particular amino acid sequence, a triplet of basic amino acids, lysine or arginine, resulted in transport of proteins into cells. This triplet that provides binding to heparin is found, for example in the nasty HIV protein, called TAT that moves on heparan sulfate proteoglycans (HSPGs) from infected to uninfected human cells and paves the way for the spread of infection. This triplet is also found in heparanase, that is first secreted by cells in an inactive form, is brought back into cells by binding to HSPGs, is activated by partial digestion and resecreted for action in the extracellular environment. This heparin-binding triplet can also be added to other proteins, e.g. the fluorescent jellyfish protein, to transport those proteins into cells.

Examination of ragweed pollen and subsequently dozens of other common allergens revealed that each one (or a close relative) possessed the unusual heparin-binding triplet of basic amino acids. The basic charged character of these sequences also determined that these parts of proteins would be present as accessible coils on the surface of the proteins. It is interesting that people suffering from the autoimmune disease of lupus produce antibodies to most of the proteins found in the nucleus of their cells. These nuclear proteins bind to nucleic acids, that mimic the structure of heparin and in many cases have triplets of heparin-binding basic amino acids. Thus, it appears that allergenic proteins enhance the chance of uptake by cells that can display them to the immune system, because of their triplet heparin-binding domains and the immune system subsequently produces antibodies that bind to other regions of the protein allergens. This explains how the antibodies are produced to these allergens, but it does not explain why some people produce antibodies to environmental antigens and healthy people do not.

Allergic people readily expand their allergies to include new allergens. What is it about these susceptible people that makes them allergic? I think that the answer is inflammation. Inflammation leads to a disruption of normal production of heparan sulfate proteoglycans and as a consequence to a change in how external proteins interact with cells involved in processing antigens for presentation to the immune system. This means that people with chronic inflammation, also called the metabolic syndrome, are not only increasingly susceptible to diabetes, arthritis, heart disease, etc. but they are also at risk for picking up new allergies. This also suggests that an anti-inflammatory diet and lifestyle changes would be of great benefit to those with allergies. Unfortunately, because of immunological memory, it will take years to deplete the population of antibody secreting cells that provide the basis for a specific allergy and during this depletion time, the allergen would have to be scrupulously avoided. It might also mean that autoimmune diseases such as type I diabetes might be treated by depletion of anti-beta cell antibodies and their secreting B cells along with a shift to an aggressively anti-inflammatory diet.

It is my belief that many of the genetic components of allergies and autoimmune diseases would not be experienced in the absence of chronic inflammation as a precipitating condition.

HELLP, Preeclampsia, Antiphospholipid Antibodies and Basic Triplets

—-the other 200 posts —-

Clotted RBCs in Capillary

Some of my research involves the unique properties of milk and the development of the immune system, so I talk to medical people, lactation researchers and occasionally discuss the control of inflammation involved in ovulation, fertilization, implantation, gestation, labor and lactation.  It is clear to me that there are a few trends in disruption of these pregnancy processes resulting from the modern increase in inflammation and gut-related problems linked with immune tolerance.  Infertility is increasing, because women are becoming more chronically inflamed.  Miscarriages and premature births/low birth weight are increasing, because chronic inflammation enhances labor.  Pre-eclampsia (high blood pressure and protein leaking into the urine) results from chronic inflammation and omega-3 fatty acid depletion.  Now an even scarier form of pre-eclampsia, HELLP (Hemolysis, Elevated Liver enzymes, Low Platelets) is on the rise.  I want to discuss HELLP to put all of these pregnancy-related problems into perspective.

HELLP, Cause and Cure Unknown?

HELLP is an autoimmune disease and I have repeatedly discussed the cause of autoimmune diseases:  1) inflammation, 2) deficiency of Tregs (immune tolerance) and 3) antigen basic triplets (antigen presentation).  When HELLP was recently brought to my attention with a sudden rise in local hospitals, I decided to see if it could be easily explained and cured, just by examining the available medical literature.  Wikipedia indicated that the cause and cure was not known and that was confirmed by local doctors, who just treat the symptoms by early deliveries and long stays for the babies in neonatal intensive care units.  My work was cut out for me.

Autoimmune Disease with Unknown Autoantigen 

An examination of the symptoms, rupture of blood cells (fibrin production), liver damage, clotting (low serum heparin), high blood pressure (capillary apoptosis), proteinuria (low heparan sulfate (HS) to prevent protein loss), pointed to some obvious treatments and the causes.  Infertility is often treated by in vitro fertilization/insemination, supported with aspirin and heparin injections to maintain gestation.  These treatments are consistent with high levels of chronic inflammation that block implantation and stimulate labor.  Infertility is also associated with antiphospholipid antibodies.  A closer look at the antiphospholipid antibodies showed that they were directed against β₂-glycoprotein-I.  So, I expected the β₂-glycoprotein-I protein to be the original target for the antibodies, the initiating antigen, but when I looked up the sequence of that protein, it lacked the expected basic triplet I have found in all  other autoantigens and allergens.  This meant to me that there was a different protein with a related sequence that started the HELLP autoimmune disease.

Attack on P-Selectin Starts Immune Autoimmunity

I checked for other proteins with related sequences and basic triplets (RKR in the carboxy terminal sequence below), and found P-selectin that is produced most abundantly in liver and on the surface of blood cells.  A quick search of the literature showed that P-selectin reacts with anti-phospholipid antibodies and has a pair of basic triplets that enhance immune presentation and make this protein a strong candidate for becoming an autoantigen.  Antibodies against P-selectin will cause clotting as seen in HELLP.

ref|NP_002996.2| P-selectin precursor [Homo sapiens]:

......carboxy terminalGTLLALLRKRFRQKDDGKCPLNPHSHLGTYGVFTNAAFDPSP

Antibiotics and Liver Damage

I suspect that HELLP is caused by a combination of liver damage and prior exposure to antibiotics (or common drugs that have antibiotic activity) that cause gut dysbiosis, i.e. loss of gut bacteria that stimulate development of the suppressive part of the immune system, e.g. deficiency in regulatory T cells, Tregs.  Examples of the type of liver damage that may lead to HELLP are excessive consumption of alcohol (alcoholic fatty liver) or high fructose corn syrup (non-alcoholic fatty liver).

HELLP from Cause to Cure

• Diet and/or infection causes liver inflammation.
• Antibiotics/drugs and/or processed foods lacking prebiotic fiber produce gut dysbiosis.
• Lack of gut bacteria needed for development of the immune system in the gut produces a deficiency of Tregs and dysfunction of immune tolerance.
• Liver inflammation, deficiency of Tregs and availability of antigens with basic triplets leads to antibodies against liver proteins.
• Chronic inflammation leads to decrease in HS production and leaky kidneys/proteinuria.
• Chronic inflammation/liver damage produces fibrin production.
• Fibrin production and low HS enhances clotting and leads to apoptosis/cell death in capillaries.
• Loss of capillaries leads to high blood pressure.
• Cure of HELLP, anti-phospholipid antibodies and pre-ecampsia, involves lowering chronic inflammation (aspirin and heparin treatment) with an Anti-Inflammatory Diet, fixing vitamin D deficiency, increasing omega 3/6 ratio,  and repairing gut dysbiosis to fix immune tolerance.
• Without these interventions, HELLP symptoms will become more severe, especially in subsequent pregnancies and additional autoimmune diseases will develop.

Celiac Causes Allergies and Autoimmune Diseases

Anti-Tissue Transglutaminase Can Lead to Hashimoto’s Thyroiditis

Celiac, gluten intolerance, causes intestinal inflammation and immunological presentation of the common intestinal protein, tissue transglutaminase (tTG). The result is anti-tTG autoantibodies that stimulate an immune attack on intestines and other tissues.

Heparan-Binding Proteins Involved in Autoimmunity and Allergy

Those familiar with my blog know that I am obsessed with heparin-binding protein domains. The reason that I am focused on these parts of proteins, is because most cells rapidly sweep heparan sulfate polysaccharides across their surfaces from sites of secretion to sites of internalization. During inflammation, proteins with strong heparin-binding domains, consisting of triplets of basic amino acids, e.g. KRK (lysine-arginine-lysine), are internalized along with the heparan sulfate. The result is an aberrant presentation of these internalized proteins to the immune system and production of inappropriate antibodies, e.g. autoantibodies.

Basic Triplets in Hasimoto’s Autoantigens

One of my hobbies is checking for the unusual occurrence of basic triplets in autoantigens and allergens. I have found dozens of examples. The most recent is associated with Hashimoto’s Thyroiditis. I knew that attack on the thyroid was common in celiacs, because the celiac autoantigen tTG (it has a basic triplet) is also present in the thyroid and the celiac autoantibodies to tTG also cause an attack on the thyroid. But the autoantigen for Hashimoto’s Thyroiditis is thyroid peroxidase (TPO).

I was momentarily perplexed, but then examined the TPO amino acid sequence and immediately found a couple of basic triplets (KKR and KRK).

MRALAVLSVTLVMACTEAFFPFISRGKELLWGKPEESRV
SSVLEESKRLVDTAMYATMQRNLKKRGILSPAQLLSFSK
LPEPTSGVIARAAEIMETSIQAMKRKVNLKTQQSQHPTD
ALSEDLLSIIANMSGCLPYMLPPK...


Hashimoto’ Thyroiditis Linked to Celiac

Then, I did a PubMed search for “celiac and Hashimoto’s”. As expected, there is a recent paper (see below) that shows that celiac commonly leads to Hashimoto’s Thyroiditis.

An obvious explanation is that the initial attack on the thyroid by anti-tTG autoantibodies of celiac leads to thyroid inflammation and presentation of TPO, with a second round of autoantibodies produced to TPO resulting in Hashimoto’s Thyroiditis. Celiac may be the initial autoimmune trigger for many other autoimmune diseases and allergies.

Autism has been associated with maternal autoimmunity and placental abnormalities. Guess where tTG is found in high abundance?

reference:
Bardella MT, Elli L, Matteis SD, Floriani I, Torri V, Piodi L. Autoimmune disorders in patients affected by celiac sprue and inflammatory bowel disease. Ann Med. 2009;41(2):139-43.

Celiac, Gluten and Trypsin Inhibitor

---the other 200 posts---   

Wheat

Summary

Forget the gluten.  Celiac is caused by trypsin inhibitors (ATI) that were increased in wheat fifty years ago to combat pests.  Immune response to ATI spreads to include gluten and transglutaminase that perpetuates the disease.  Celiac is an unexpected consequence of traditional plant breeding that could be fixed with GMO approaches.

Plants Protect Themselves with Antibiotics, Pesticides and Trypsin Inhibitors.

Plants respond to pathogens and pests by making themselves toxic.  Thus, plants produce natural antibiotics, phytoalexins, a.k.a. phytochemicals, polyphenolics or antioxidants, to kill bacteria and fungi.  They also produce chemical pesticides and proteins, e.g. trypsin inhibitor, that block the digestion and utilization of plant proteins by insects.  One of these trypsin inhibitors makes ground soybeans inedible until it is removed in water rinses during the production of tofu.  Another of these trypsin inhibitors, in wheat, is the cause of celiac.

Plants Target the Nerves, Immune Cells and Intestines

Plants have evolved chemicals and proteins that attack and punish plant-eating animals.  A single molecule of caster bean toxin protein, for example, can kill a human cell.  Plants produce some of the most toxic molecules on earth.  The nervous system of insects and other herbivores is typically targeted by plants.  Many recreational drugs, e.g. opioids, THC, nicotine, caffeine, etc., for example, are made by plants in self defense.  Human nerves respond to these natural pesticides and the bitter taste and the vomit reflex help us to detect and avoid toxic phytochemicals.  Gluten proteins contain polyglutamine stretches of amino acids that resist digestion and bind to intestinal cells.  Seed lectins bind to the glycoproteins on the surface of the intestines and inhibit digestion.  Wheat seeds also contain an inhibitor of starch and protein digestion, the amylase/trypsin inhibitor, ATI.  ATI binds to the receptors on immune cells that trigger general inflammatory responses to pathogens, e.g. TLR4.  It is the ATI in wheat that starts an immune response to gluten and celiac.

Wheat trypsin inhibitor causes celiac and autoimmunity

ATI Increased to Make Wheat Resistant to Pests

More than fifty years ago, plant breeders began to screen wheat varieties for resistance to pests.  Breeding ultimately resulted in enhanced pest resistance that resulted from increased production of ATI in wheat kernels.  Modern wheat flour contains modest changes in gluten and other components over the last century with the singular exception of ATI, which has increased about 50 fold.  It is also interesting that ATI is a major wheat allergen.  This suggests that celiac starts as an allergy to ATI present in wheat flour.

Celiac Results from Superfine Milling of High-ATI Wheat

Wheat has been milled more and more finely to improve the shelf-life of bread flour.  The inedible bran and the germ are first removed from the wheat kernels and then the endosperm is ground so finely that the starch granules are broken.  Even "whole wheat flour" is ground in the same way and the bran and germ are simply added back to make it “whole.”  The important point here is that superfine milling results in starch that is readily digested by amylase in the small intestines, instead of acting as soluble fiber to feed gut flora.  The result of eating bread from superfine flour is that gut flora are starved for soluble fiber and the immune system is depleted of Tregs that would otherwise suppress allergy and autoimmunity.  Superfine milling of high-ATI wheat presents ATI to an immune system that is primed for allergy.

ATI is a Good Immunogen

Allergy development requires 1) inflammation, 2) an appropriate immunogen and 3) lack of Tregs (immune system cells that develop in the lining of the intestines and block allergies and autoimmunity.)  The modern milling of wheat flour eliminates a major source of soluble fiber, starves gut flora and reduces Tregs, but allergy development still requires inflammation and an appropriate immunogen.  An immunogen is a protein that will interact with cells of the immune system to produce antibodies and activate aggressive attacks.  I have found that all proteins of food or the environment, i.e. allergens, or of the body, i.e. autoantigens, that act as immunogens to initiate allergies or autoimmunity have the same sequence of three amino acids, a "basic triplet."  ATI has a characteristic basic triplet in its protein amino acid sequence and that is why it is a good immunogen to initiate allergies.

Allergy to ATI is Aggrevated by TLR Recognition of ATI

ATI enriched, superfine flour Is a powerful initiator of allergies, because it starves gut flora to block Treg production and is a good immunogen, but the immune system will still ignore ATI in the gut, unless inflammation is also activated.  Unfortunately, ATI actively stimulates inflammation of the intestines by specifically binding to TLR4, which is the receptor that also binds/recognizes the LPS of bacteria.  Thus, ATI is a way for the wheat plant to defend its seeds by triggering excessive Intestinal inflammation.  Inflammation, immunogen and Treg insufficiency is the ATI allergy trifecta.

Wheat ATI Allergy Leads to Celiac

First exposure to ATI and development of an allergy will make subsequent expose to wheat proteins more immunologically intense.  I discussed the response of the intestinal lining to gluten in previous posts.  Wheat gluten proteins are adapted to provide nutrients for growing wheat embryos and to provide defense against pathogens and herbivores.  Gluten proteins contain long stretches of amino acid glutamine, which is poorly digested by gut enzymes.  The glutamine is also converted into glutamate by the gut enzyme, transglutaminase, tTG.  Unfortunately, during the process, the enzyme is covalently connected to the undigested gluten fragments.  The allergic ATI reaction combined with gluten/tTG conjugates, leads to presentation of the gluten/tTG to the immune system and antibody production agains both gluten and tTG.  Subsequent exposure to gluten results in the autoimmune disease of celiac.

Celiac is Self-Perpetuating

The aggressive immune attack on the intestines in response to eating gluten-containing grains, is bad in itself, but it also causes a series of related autoimmune diseases.  Attack on the intestines also disrupts the development of the lining of the intestines, which in turn disrupts the community of bacteria and fungi, gut flora, that are essential for digestion of plant polysaccharides, soluble fiber, and the development of the immune system.  Gut flora dysfunction results in vitamin deficiencies, food intolerances and autoimmunity.  Thus, celiac is self-perpetuating, because it causes inflammation, immunogen presentation and Treg deficiency.

Celiac Causes Numerous Autoimmune Diseases

Celiac is often associated with other autoimmune diseases, because it causes them.  Antibodies to tTG are diagnostic for celiac and the autoimmune attack on the intestines is mediated by anti-tTG antibodies.  But anti-tTG antibodies of celiac don’t just attack the intestines, they attack any other tissues that have tTG, such as the thyroid gland and hair follicles.  Thus, it should not be a surprise that celiacs are at high risk for autoimmune disease, e.g. Hashimoto’s thyroiditis, of the thyroid gland, including both hypothyroid and hyperthyroid diseases, depending on which region of the thyroid is attacked.  Some forms of hair loss, alopecia, are also initiated by autoimmune attack on the tTG in hair follicles.  Persistent exposure of celiacs to gluten will result in a cascade of autoimmune diseases as other body antigens are presented to the immune system and tissues with those antigens are targeted and attacked to produce arthritis, vitiligo, etc.

Pest Resistance, Plant Breeding and GMO Solutions

Genetic modification of plants occurs every time seeds are planted.  Traditional plant breeding by selecting desirable individual plants grown from crosses of selected parents is one form of genetic modification.  Specifically introducing desired genes using recombinant DNA techniques is another, more controlled method.  Traditional plant breeding has systematically destroyed the diversity of crop plants by loss of genes that are not selected, but even the traits, such as pest resistance, that provide benefit, have also brought unintended consequences.  We now have grains with many desirable features of high yield and disease resistance, but they also provide increased risk of celiac, gluten intolerance and associated autoimmune diseases.  Maybe it is time to consider GM techniques as a safer alternative to fix modern wheat and to examine milling approaches to save our gut flora.

Health Diagrams II — Curing Autoimmunity and Allergies

Cure for Celiac and Autoimmunity

Celiac and other autoimmune diseases are perpetuated by the presence of the corresponding autoantigen/allergen, in this case tTG and gluten proteins, and a deficiency of Tregs.  Oddly enough, some pathogens (Helicobacter pylori) and parasites (Helminth worms) stimulate Treg development in the lining of the intestines, in addition to normal gut flora, Clostridium spp.  It may be the relative absence of pathogens and parasites in affluent societies that reduces Tregs and enhances the incidence of allergies and autoimmunity.  Antibiotics and the antibiotic activity of pharmaceuticals in general may also contribute to Treg deficiencies by damage to gut flora.  Clearly, the repair of gut flora and reestablishment of the associated immune system will go a long way toward curing autoimmune diseases such as celiac.  Celiac, however, provides the added complexity that it damages the ability of the intestines to maintain a functional gut flora.  Thus, the cure for celiac would require simultaneous repair of both the gut and its flora, e.g. by a  fecal transplant and supportive diet containing numerous soluble fibers to which the donor flora have been previously adapted, i.e. lacking antigenic triggers.

Cytstic Fibrosis Overproduces Tissue Transglutaminase and Contributes to Celiac

Tissue transglutaminase (tTG or TG2) is produced in excess in some diseases, such as cystic fibrosis, and contributes to inflammation and disease symptoms. tTG also readily moves in and out of cells by virtue of its basic triplet and when in the cytoplasm, tTG is ubiquinated and degraded by proteosomes. I have previously pointed out that internalization and proteosome degradation are also the initial steps in processing of proteins for presentation by the immune system and antibody production, i.e. turning a cellular protein into an autoantigen involved in autoimmune disease.

Here is an image of a computational protein model of tTG I drew with Chimera. I have highlighted the basic triplet to show its exposure to facilitate transport.

Oxidative Stress Alters tTG and Triggers Inflammation

A recent article also links tTG intracellular chemical modifications (SUMOylation), which are linked to oxidative stress, to activation of NFkB and inflammation. Thus, tTG is a major player in controlling cell surface interactions with potentially toxic materials such as polyglutamine-rich gliadin, as well as triggering inflammation in response to oxidation stress.

Cystic Fibrosis Causes Overproduction of tTG

When I read that cystic fibrosis results in an increase in the production of tTG in lungs, I immediately thought of the role of tTG as an autoantigen in celiac disease and the progression of celiac into Hashimoto’s thyroiditis, which has the same autoantigen, tTG. I suspected that the overproduction of tTG and inflammation in cystic fibrosis should increase tTG autoantibody production and tTG-mediated autoimmune diseases of celiac and Hashimoto’s thyroiditis.

Extra tTG Leads to Autoimmune Celiac

A quick PubMed search of CF and celiac, revealed a study of comorbidity between CF and celiac in Norway. Just as expected, the two diseases occur together with a frequency three times higher than predicted by coincidence. CF stimulated tTG overproduction was driving the development of celiac.

references:
Luciani A, Villella VR, Vasaturo A, Giardino I, Raia V, Pettoello-Mantovani M, D'Apolito M, Guido S, Leal T, Quaratino S, Maiuri L. SUMOylation of tissue transglutaminase as link between oxidative stress and inflammation. J Immunol. 2009 Aug 15;183(4):2775-84.

Fluge G, Olesen HV, Gilljam M, Meyer P, Pressler T, Storrösten OT, Karpati F, Hjelte L. Co-morbidity of cystic fibrosis and celiac disease in Scandinavian cystic fibrosis patients. J Cyst Fibros. 2009 May;8(3):198-202.

Inflammatory Proteins Bind Heparin

Particular amino acid sequences mark a protein for secretion, binding to heparin, uptake and internalization into the nucleus.

You can tell a lot about a protein from the sequence of its amino acids. Basic amino acids (arginine and lysine) arranged in groups, for example, usually mean (if it is an extracellular protein) that a protein binds to heparan sulfate proteoglycans.

It seemed strange to me that heparin-binding was so simple when I tried to determine the rules for heparin-binding by looking at the structures of several hundred proteins known to bind to heparin. Since heparin is heavily sulfated and the sulfates are negatively charged, at first I just color-coded the positively-charged , basic amino acids (blue) to look for oppositely charged heparin-binding sites on the surface of the proteins. Obvious blue patches were found on the surfaces of all of the proteins that bound to heparin and scattered blue spots were on the surfaces of other proteins. Moreover, similarly color-coded amino acid sequences showed that the blue patchs almost always had pairs of basic amino acids flanked within six amino acids by a third basic amino acid, i.e. BBxxxxB, where B is either arginine (R) or lysine (K) and x is a hydrophobic amino acid. It was surprisingly simple.

I was shocked at the simplicity, because most binding sites are made up of parts of regular secondary structures of helices or pleated sheets. If there were basic amino acids on these structures, which bound to heparin on one side, then the R/K would be repeated at specific intervals. For a helix, for example, the repeat would be BxxBxxB, because it takes three amino acids to return to the same side as the amino acids wind around in the helix. For the pleated sheet, the amino acids alternate on each side of the sheet, so the pattern is BxBxB. I found these kinds of heparin-binding domains also. The hardest patterns to find from sequences are groups formed as R/K’s on neighboring helices or sheets are brought together in the final folding of the protein.

One of the reasons that the simple pair plus one (BBxxxxB) was found so easily, is because the sequence is typically found on coils that only take shape in the presence of heparin. Thus the rigid binding of the domains to heparin is a result of the shape of the protein induced by the heparin. A related example of this phenomenon is the facilitation of the formation of amyloid fibers in the presence of heparin. The beta amyloid of Alzheimer’s disease for example, consists of a stack of small amyloid peptides with basic amino acids that line up and bind heparin along the length of the stack. Heparin is also an essential component in the amyloids of diabetes. Prions also seem to involve heparin. It is assumed that the cytoplasmic tau fibers of Alzheimer’s disease also have a similar facilitating polyanion (if not heparin), but it has not been identified.

Because of the essential nature of HSPG recycling, it is interesting that amyloid formation is toxic when the amyloid is in contact with cells. Perhaps the amyloid paralyzes HSPG recycling and thereby kills the cells. Treatments that disrupt amyloid binding to heparin, e.g. methylene blue, spare the neurons. This would also suggest the utility of berberine, a fluorescent dye for heparin, which is also a common herbal cure for arthritis, in treatment of many amyloid diseases.

The pair plus one is the minimal grouping of R/K’s that binds heparin, but larger groups bind more strongly and increase the complexity of the interaction between proteins and a cell. A triplet of R/K’s results in a protein binding to the heparan sulfate proteoglycans (HSPGs) on the surface of a cell, but as the HSPGs are recycled by being brought into vesicles within the ce)ll, the bound proteins are also internalized. These internalized proteins are then fused with lysosomes and the proteins are at least partially degraded by proteases. The proteins were released from the HSPGs by the degradation of the heparan. The modified proteins have a variety of fates. Some return to the Golgi for secretion, e.g.HSPGs and heparanase, whereas others are degraded in proteosomes and presented as potential antigen fragments on surface receptors, and still others are are transported to the nucleus. Those proteins transported into the nucleus have four R/K’s or to neighboring pairs of R/K’s, e.g. HIV-TAT, heparanase and transglutaminase 2 (?) Heparanase is intimately involved in cancer proliferation and transglutaminase is involved in Celiac and inflammation.

I have reproduced below the sequences of several human proteins from the National Center for Biotechnology Information. For simplicity, I have deleted the “uninteresting” amino acids between the heparin-binding domains. You will also see an occasional negatively charged amino acids (D/E) within the R/K groups and their hydrophobic neighbors. These amino acids bind to the amino sugars of the heparin.

transglutaminase 2
M---REKLVVRR---KFLKNAGRDCSRR---RRWK---KIRILGEPKQKRK

heparanase
M---REHYQKKFKNSTYSR---KLLRKSTFKNAK---RRKTAKMLKSFLK---RPGKK---KKLVGTK---KRRKLR

Tat [Human immunodeficiency virus 1]
M---KCYCKK---RKKRKHRRGTPQSSK---KEQKKTVASKAER

Chain A, Interleukin- 1 Beta
A---KKKMEKRFVFNK

lactoferrin
M---RRRR---RNMRKVR---RRAR---KGKK---KRKPVTEAR