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Michael Rizzo

Michael RizzoCooperating Doctoral Program: Cell and Molecular Biology

EITS Track: Biomedical Toxicology

Education: B.S., Genomics and Molecular Genetics, Michigan State University

Research Interests:
My research interest is in the area of immunotoxicology. My thesis will be focusing on Δ(9)Tetrahydrocannabinol (THC), the main psychoactive compound found in Marijuana, and its role in further immunosuppression of HIV-infected individuals. HIV-infected individuals are characterized as having severe immunosuppression, indicated by low levels of CD4+ T cells. Effective treatment (Highly Active Antiretroviral Therapy- HAART) for diminishing the circulating virus and restoring CD4+ T cells is available. However, 25% of HIV patients taking HAART do not have a restoration in CD4+ T cells (HIV Discordant), thus remaining immunocompromised. It has been reported that 25-37% of HIV patients use medical Marijuana to relieve symptoms of the virus. Numerous research findings have shown that Marijuana, in particular THC, causes immune suppression in normal, healthy individuals but not severe enough to be of particular concern. The major question that arises with medical Marijuana use in HIV patients is whether the THC is causing further immunosuppression. Of particular focus are the HIV Discordant patients that don't respond well to HAART and remain immunocompromised. These individuals are already at risk of opportunistic pathogens and developing cancer. We believe that Marijuana use in HIV Discordant patients will cause further immunosuppression and make these individuals even more at risk of developing opportunistic diseases. So far, the Kaminski lab has shown that there is a THC-mediated suppression of IFNa production by plasmacytoid dendritic cells (pDC) in both healthy and HIV-infected donors. pDCs are critical in viral host defense and IFNa is the key antiviral cytokine secreted by pDCs. Another major finding was the THC-mediated suppression of IL-7R mRNA and surface levels in T cells stimulated by IFNa in healthy donors. IL-7R is a critical marker of T cell clonal expansion and adaptive immunity. THC is believed to be suppressing these responses through its interactions with Cannabinoid receptors 1 and 2 (CB1 and CB2), which have been highly studied in the Kaminski Lab. My thesis will be built on one of these key findings and taking a more in depth look at the mechanisms by which THC causes immunosuppression in HIV patients.

Major Professor: Norbert Kaminski, Pharmacology and Toxicology