Dr. Charu Kaushic

HIV transmission and Inflammation of the Mucosal Layer

Professor, McMaster University

As Dr. Charu Kaushic investigated how female sex hormones and the menstrual cycle regulate the immune system during her post-doc, a nagging question kept returning. “I was looking at the immune system under normal conditions,” explains Dr. Kaushic. “But I kept asking myself “what would happen if there was an infection?”” Though the lab wasn’t involved with this line of study at the time, this question would set the future of her research career—investigating the relationships between viral infection, hormones, and the mucosal immune system of the female genital tract.

Women, and young women in particular, disproportionately represent new HIV infections in many South African countries. Dr. Kaushic’s lab at McMaster University was one of the first to advocate for research into mucosal transmission of HIV in order to shed light on how transmission through heterosexual sex could be stopped. It is, as Dr. Kaushic explains, a major gap in the literature. “For the first 20 years of the epidemic, researchers were looking at the easiest thing to examine, which was HIV in blood. Those studies were important for the development of antiviral therapies, but it hasn’t helped us understand how the virus is transmitted sexually.”

The lining of the reproductive tract is made up of epithelial cells that form a mucosal layer. These cells are the first to interact with the virus, yet they don’t get infected. Dr. Kaushic’s lab was the first to show that epithelial cells in the reproductive tract respond to HIV by activating danger signals and making inflammatory mediators. Though it’s an appropriate response to infection, this inflammation itself is problematic when it comes to HIV exposure. “The epithelial cells of the mucosal lining come apart a little bit due to the local inflammation. The virus takes advantage of that by crossing the epithelial lining, gaining access to the interior of the body” says Dr. Kaushic. Not only does the virus gain entry through the lining, but it benefits from the inflammatory response set in motion by the epithelial cells—plenty of target cells to infect.

At the intersection of all her work is a recent CIHR Mucosal Team Grant that examines the intersection of hormones, the vaginal microbiome and inflammation “The missing piece of the puzzle is the microbiome in the vaginal tract which is regulated by hormones. In turn, the type of bacteria that are there regulate whether there is inflammation or a healthy environment,” Dr. Kaushic explains. The team grant, one of the three, awarded in a Canada wide competition, by a partnership between CIHR and Bill and Melinda Gates Foundation, started in 2015 for a 3-year term.

Though her research is at the cellular level, Dr. Kaushic realizes how it can inform the everyday choices women make about their sexual health. After one particular OHTN event early in her career, health care providers who were audience members came up to her to ask advice on what to tell their patients. “It came as a shock to me. I, like many other scientists, had a completely academic background before then.” Now, community outreach, consultation and education is a significant part of Dr. Kaushic’s way of conducting research. “I think my work has important implications that women need to understand. Through all the ups and downs of running a research lab, empowering women to make informed choices about their sexual health is my driving force.”

The Canadian Association for HIV Research (CAHR), the CIHR HIV/AIDS Research Initiative, the Canadian Foundation for AIDS Research (CANFAR), the CIHR Canadian HIV Trials Network (CTN) and the Canadian HIV Vaccine Initiative (CHVI) Research and Development Alliance Coordinating Office (ACO) would like to thank Dr. Kaushic for her significant contributions to our understanding of HIV. Her work is part of a larger Canadian research effort that is making a difference in the lives of those affected by HIV in Canada and around the world.

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