HIV Disrupts the Replication of Brain Stem Cells

A prominent problem in AIDS is a form of dementia that robs one’s ability to concentrate and perform normal movements. Scientists at the Burnham Institute for Medical Research (Burnham) have discovered how HIV/AIDS disrupts the normal replication of stem cells in the adult brain, preventing new nerve cells from forming.

Drs. Stuart Lipton, Marcus Kaul, Shu-ichi Okamoto and their colleagues uncovered a novel molecular mechanism that inhibits stem cell proliferation and that could possibly be triggered in other neurodegenerative diseases as well. These findings were made available to medical researchers today through priority publication online by the journal Cell Stem Cell.

A normally functioning adult human brain has the ability to partially replenish or repair itself through neurogenesis, the proliferation and development of adult neural progenitor/stem cells (aNPCs) into new nerve cells. Neurogenesis can take place only within specific regions of the brain, such as the dentate gyrus of the hippocampus.

The hippocampus is the brain’s central processing unit, critical to learning and memory. aNPCs differentiate, adapt, and assimilate into existing neural circuits and mature with guidance from neurotransmitters, the chemical substances that nerve cells use to communicate with one another.

The brain’s self-renewal through neurogenesis is impaired in AIDS dementia, Alzheimer’s, Huntington’s, and other neurodegenerative diseases, as evidenced by a greatly reduced number of aNPCs in brain tissue from individuals suffering from these diseases. The Burnham team focused on the determining the effect of a protein associated with AIDS, called HIV/gp120, which plays a key role in the pathogenesis of AIDS dementia.