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Going micro to tackle HIV

BIOMARKER: “In diseases such as cancer and HIV, where cells proliferate uncontrolled or virus cells multiply enough to overwhelm the body’s defence mechanism, microRNA could throw light on whether they are aiding or impeding the normal function of the cell.” — PHOTO: AFP   | Photo Credit: SCOTT OLSON

Scientists from India have stumbled on a trail so faint that it could well be a dead end but were it to bear out, could mean a new way to understand the AIDS-causing Human Immunodeficiency Virus (HIV). For over a decade now, Beena Pillai, a researcher at the New Delhi-based Institute of Genomics and Integrative Biology, has been looking at how ribonucleic acid (RNA) — a close cousin of deoxyribonucleic acid (DNA) — controls the production of proteins from the genetic instructions encoded by DNA. However there are other kinds of RNA that don’t directly play a role in the protein-manufacturing process. One of them, called microRNA, is like the address on an envelope that tells the RNA where exactly to latch onto to tweak the synthesis of a protein. Thus, in diseases such as cancer and HIV, where cells proliferate uncontrolled or virus cells multiply enough to overwhelm the body’s defence mechanism, microRNA would be found in unusual concentrations — either very high or very low — and throw light on whether they are aiding or impeding the normal function of the cell.

MicroRNA as an indicator

To better understand the link between microRNA and HIV, Ms. Pillai and her colleagues teamed up with Y.R. Gaitonde Centre for AIDS Research and Education (YRG CARE), an HIV/AIDS care and support centre in Chennai that was once led by Dr. Suniti Solomon, who identified India’s first HIV case in 1986. Being one of the few places in India that maintained systematic records of how soon HIV patients progressed to contracting AIDS, says Ms. Pillai, meant that YRG had identified a rare group of patients — called long-term non-progressors (LTNPs) — who had tested HIV positive more than seven years ago but were yet to contract AIDS. After scanning and comparing the DNA of patients who progressed extremely rapidly to AIDS with LTNPs, it emerged that the latter had extremely low levels of two specific kinds of microRNA, miR-155-5p and miR-382-5p. Previously too, other researchers from India and elsewhere have identified 13 of these “anti-HIV” microRNA that seemed to significantly increase or decrease in HIV patients depending on how fast they contracted AIDS. While that doesn’t imply that low microRNA means better resistance to HIV, it is now possible to build a predictive, genetic test with this data set to check if people responded differently to HIV — and going forward, if they would contract AIDS.

“Therapies based on this knowledge are still very far off but we could have drug-like molecules that are designed to target HIV molecules through this microRNA or engineered stem cells that have altered, protective levels of the microRNA,” says Ms. Pillai.

To Samir Brahmachari, former Director General, Council of Scientific & Industrial Research (CSIR) — who was involved with the work and sparked off Ms. Pillai’s investigation in 2005 — more than new drug targets or improved therapies for HIV, this was an example of a theory conceived, executed and tested in India. “It is early days but we were the first to show that microRNA can interact with HIV genes. We thought it always blocked HIV but the behaviour is more complex,” he says, emphasising that work now remained to identify the entire network whereby more such RNA combined to impede the progress of HIV.

jacob.koshy@thehindu.co.in

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Printable version | Jan 21, 2021 12:05:45 PM | https://www.thehindu.com/opinion/op-ed/Going-micro-to-tackle-HIV/article14467318.ece

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