HIV triggers the ‘opposite of cancer’ in the brain

From Nature:

Brain A study showing how HIV could prevent the brain from making new neurons offers an explanation for why some AIDS patients get dementia — and suggests a possible treatment. Researchers aren’t sure what causes the condition, which afflicts 10-30% of people with HIV and causes symptoms including forgetfulness and leg weakness. If untreated with antiretroviral drugs, sufferers can turn comatose. Biologists have two theories to explain AIDS-related dementia. It could be that when HIV infects a type of white blood cell called a macrophage, the cell pumps out inflammatory chemicals to battle the infection that also, unfortunately, wipe out neurons.

Or HIV could inflict its damage more directly. One previous study showed that a protein in the virus’s shell — called gp120 — can stop brain stem cells from dividing. Such new stem cells are needed to make new neurons. Neural stem cells in the transgenic mice also contained more of a protein called p38 than normal mice. In healthy cells, p38 guards against cancer by halting cell division when DNA strands get broken. If HIV prompts so much p38 that it stops normal cells from dividing, “it’s the opposite of cancer”, says Lipton. The researchers also found other proteins linked to p38 in the neural stem cells of the gp120-expressing mice.

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