Research by Sunit K. Singh, a senior scientist with the Centre for Cellular and Molecular Biology (CCMB), has found that neurologic disorders associated with HIV type 1 affect 40 per cent to 70 pc of infected individuals. Outcome of the research was published in The Journal of Neuroscience, a high impact international scientific journal, recently.
The report highlights a new mechanism of involvement of cellular microRNA (miR-101) for perturbation in the permeability of human brain micro-vascular endothelial cells exposed to HIV Tat protein.
Dr. Singh said HIV Tat protein is known to be secreted out extra-cellularly from the infected cells and affects the neighbouring uninfected cells in bystander fashion. This, the senior scientist said, was a very interesting finding where a viral protein affects the permeability of BBB through microRNA mediate pathway.
The finding adds value in the understanding of the basic mechanisms involved in HIV neuro-pathogenesis.
Explaining his study in detail, Dr. Singh said human brain is protected by a barrier called “Blood Brain Barrier (BBB)”, which prevents entry of unwanted chemicals, bacteria, virus and others into the brain. Thus the brain is protected from most of the infections. However, AIDS virus does find a way through this barrier and cause neuroAIDS, he stated.
The ability of AIDS virus to cross the BBB barrier has been a topic of research world over. It is known that a protein called “HIV-I Tat C” leads to decrease in the number of molecules called cadherins that are sort of building blocks for the barrier. Because of this decrease in cadherins the barrier becomes weak and AIDS virus would cross the barrier, he explained.
Research at CCMB has shown that HIV-1 Tat C protein increases the expression of a small piece of RNA called miR-101. The increase leads to decrease in production of cadherin molecules. Thus, the CCMB research has provided the main link in the process, he claimed. The findings contribute to the understanding of HIV invasion into the brain. The findings might also facilitate designing strategies to prevent HIV virus by targeting selected miRNAs, he hoped.
Outcome of the research was published in The Journal of Neuroscience