Washington, March 5 : A team of researchers at the Institute of Virology of the German Research Center for Environmental Health has found that neural progenitor cells - which are capable of developing into different types of brain cells and have an enormous potential for repair processes in the brain - can form HIV reservoirs in the brain to impair infected individuals' memory functions and movement, which may later progress to serious dementia.
The new finding springs from a follow-up study to a previous research that revealed that astrocytes - the most abundant cells in the brain that support functions of nerve cells and protect them from harmful agents - form a reservoir for HIV, and represent a serious obstacle to elimination of the virus from infected individuals.
Dr. Ruth Brack-Werner, who led both the studies, used a multi-potent neural progenitor cell line, which can be grown and developed to different types of brain cells in the laboratory, in her research.
After exposing the neural progenitor cells to HIV, she and her colleagues examined the cultures for signs of virus infection for 115 days.
HIV was found to persist in these cultures during the entire observation period. The cultures released infectious HIV particles for over 60 days, and contained information for production of HIV regulatory proteins - Tat, Rev and Nef - for even longer.
The researchers also examined neural progenitor cell populations cells with persisting HIV for differences from uninfected cells.
They found that HIV persistence had an influence on the expression of selected genes and on cell morphology, but did not prevent their development to astrocytes.
Based on their observations, the researchers came to the conclusion that HIV persistence has the potential to change neural progenitor cells.
"Our study indicates that neural progenitor cells are potential reservoirs for HIV and that HIV persistence has the potential to change the biology of these cells," Dr. Brack-Werner says.
She says that her future studies will investigate the influence of HIV infection on important functions of neural progenitor cells, such as migration to diseased regions of the brain and development of different types of brain cells.
Subsequently, the research team will investigate how HIV changes neural progenitor cells and, importantly, how to protect neural progenitor cells from harmful effects of the virus in HIV infected individuals.