What’s worse than a TNF typhoon resulting from methamphetamine use? The answer is a TNF typhoon resulting in dementia from HIV infection of the brain.
Combine methamphetamine with HIV in the brain and the result is a Parkinson’s type of paralysis.This sounds like very morbid subject matter to pursue out of curiosity, but if you put heparin into the equation, as I always do, it all becomes very interesting.
Here are pieces to the big picture:
HIV, the AIDS virus, infects cells of the immune system and causes chronic inflammation. The inflammation causes a disruption of heparin metabolism and since heparin is a major part of the matrix that holds together the endothelial cells that line the capillaries that feed the brain, the capillaries leak, i.e. there is a leak in the blood brain barrier. HIV-infected cells can pass out of the capillaries and into the brain. Here comes the insidious part, HIV produces a protein called TAT.
I drew a graphic of TAT with the basic amino acids in blue. The sequence of this nasty little protein shows how it gets around. It is secreted from cells, attached to heparan sulfate proteoglycans. It sticks tightly to heparin (yellow and red stick figures, sticking to ribbon of TAT), because of the patches with three and four adjacent basic amino acids.
Frequently, the TAT will just be secreted and then sweep over the surface of the infected cell and be brought back into the cell on the circulating HSPG.DPVDPNIEPWNHPGSQPKTACN
RCHCKKCCYHCQVCFIKKGLGI
SYGRKKRRQRRRPSQGGQTHQ
DPIPKQPSSQPRGDPTGPKE
A protein with three adjacent basic amino acids will get swept into a cell. All allergens that I have examined have this internalization triplet of basic amino acids. TAT is so powerful, that if it is chemically linked to the larger fluorescent protein from jelly fish (left with green, fluorescent amino acid derivative down the center), the whole fluorescent protein is dragged into cells.The TAT can move from the HSPGs of an HIV-infected cell to neighboring cells with HSPGs. The TAT then gets taken into the cytoplasm of the next cell. Four adjacent basic amino acids are the signal that transports a protein to the nucleus and into the nucleus. It is in the nucleus that TAT really causes trouble. The TAT can move from an infected immune cell in the brain to neurons. TAT can kill neurons and stimulate other cells to produce TNF.
Methamphetamine also causes a TNF storm in the brain. This is a quick way to start the wasting symptoms that TNF in known for -- it is also call cachexin, after the wasting process of cachexia. If methamphetamine is given to someone with neurological symptoms of HIV, then the neuropathology is further exaggerated into a Parkinson’s type of paralysis. The TNF production of both is additive.
TNF production by methamphetamine brings up the consequences of the very closely related compound amphetamine (Adderall, Dexedrine) used by children and young adults (college age) as a treatment for ADHD.
reference:
Theodore S, Cass WA, Nath A, Maragos WF. 2007. Progress in understanding basal ganglia dysfunction as a common target for methamphetamine abuse and HIV-1 neurodegeneration. Curr HIV Res. May;5(3):301-13.
