Department of Medicine
Research Associate Professor
Apoptosis and cell death; Bioinformatics; Endocrinology; Gene Expression; Gene therapy; Genomics and proteomics; Immunology; Molecular and Cellular Biology; Molecular Basis of Disease; Neurobiology; RNA; Viral Pathogenesis
Dr. Mahajan has established herself as an investigator in the area of neuropathogenesis of HIV-1 in the context of drug abuse. She has initiated several new projects that investigate the role of a unique key signaling molecule in the dopaminergic pathway that impacts drug addiction, depression and other neurological disorders. Her focus has always been on collaborative, interdisciplinary partnerships between various Departments within UB that include the Institute of Lasers, Photonics and Biophotonics, Research Institute of Addiction, Dept of Computer Science and Engineering, Dept of Pharmaceutical sciences and the Department of Bioengineering. This inclusive strategy has facilitated the emergence of a robust, innovative clinical translational research program for our Division that continues to grow steadily. Dr Mahajan has obtained independent research funding from NIDA, the pharmaceutical Pfizer, US- Fulbright and other Private Foundations such as Dr. Louis Skalrow Memorial trust to conduct some of these research projects. Dr. Mahajan is Director of Research of the Division of Allergy, Immunology & Rheumatology. She supervises the research training of the Allergy fellows,Medical residents, graduate and undergraduate students. Dr. Mahajan has presented her research work at National and International conferences and was an invited speaker at several seminars and colloquiums. She has authored over 95 publications in several top quality peer reviewed journals and has thus demonstrated a high level of scholarly productivity. She is a reviewer and an adhoc member of the editorial board of several journals in her field.
The following is a brief synopsis of her research interests.
HIV neuropathogenesis in the context of drug abuse: We proposed that Opiates act as co-factors in the pathogenesis of HIV-1 infections by directly suppressing immune functions of the host through interactions with mu-opioid receptors on lymphocytes. Exacerbation of HIV encephalopathy (HIVE) is observed with opiate abuse. The mechanisms underlying HIVE are currently undetermined however, they likely to include the generation of endogenous neurotoxins combined, perhaps synergistically, with bioreactive HIV-1 envelope proteins. We believe that these proposed mechanisms may work through a common signal transduction mechanism activating dopamine D1 receptors in the nucleus accumbens of the brain. Opiate abuse by HIV-1 infected subjects may exacerbate the progression of HIVE as a consequence of the combined effects of HIV-1 induced neurotoxins plus opiate induced increases in the D1 receptor activation. We hypothesize that the dopaminergic signaling pathway is the central molecular mechanism that integrates the neuropathogenic activities of both HIV-1 infections and the abuse of opiate drugs. In this context our investigation is focused on the DARPP-32 signalling pathway. Addictive drugs act on the dopaminergic system of the brain and perturb the function of the dopamine- and cyclic-AMP-regulated phosphoprotein of molecular weight 32 kD (DARPP-32). DARPP-32 is critical to the pathogenesis of drug addiction by modulating both transcriptional and post-translational events in different regions of the brain. DARPP-32 is localized within neurons containing dopamine receptors and is a potent inhibitor of another key molecule in the dopaminergic signaling pathway, protein phosphatase 1 (PP-1). We propose that the sustained silencing of DARPP-32 gene expression using specific siRNA delivered to the brain is an innovative approach for the treatment of drug addiction. The specific challenge of the proposed project is the non-invasive delivery of biologically stable, therapeutic siRNA molecules to target cells within the brain. We are developing biocompatible nanoparticles to both protect DARPP-32 specific siRNA against degradation and deliver it from the systemic circulation across the BBB to specific dopaminergic neurons in the brain of patients with opiate addictions.
While examining neuropathogenesis of HIV, we became interested in the role of the blood-brain barrier (BBB) in HIV neuropathogenesis with the objective of developing therapeutic interventions to prevent and limit the progression of HIV associated neurological disease. The blood-brain barrier is an intricate cellular system composed of vascular endothelial cells and perivascular astrocytes that restrict the passage of molecules between the blood stream and the brain parenchyma. We evaluated and validated both the 2 and 3 dimensional human in-vitro BBB models in my laboratory, that allowed examining permeability of virus, effects of drugs of abuse on BBB permeability, mechanisms of BBB transport, and tight junction modulation. Our goal remains to determine the impact of current and potential CNS antiretrovirals, psychopharmacologic, and other medications on the integrity of the BBB in HIV associated neurological disorder and other neurodegenerative diseases. Additionally, We also investigate mechanisms that underlie drugs of abuse induced neuronal apoptosis.
Systems biology approach:
We expanded our investigation to include functional genomic/proteomic analyses that allowed characterization of gene/ protein modulation in response to a drug stimulus or under a specific disease condition. We developed an expertise in these large-scale genomic and proteomic studies and the genomic studies helped identify key genes that underlie molecular mechanisms in drug addiction, HIV diseases progression, and allowed examination of the interplay of genes and environmental factors. The proteomic studies confirmed the presence of specific proteins that regulate key biological processes in drug addiction and HIV diseases progression. Recently, We have expanded my research program to include microbiome analyses and incorporated the utility of the computational drug discovery platform (CANDO) model that allows studying interaction between protein structures from microbiome genomes and determine the interactions that occur between them and small molecules (drugs and human/bacterial metabolites that are already a part of or continue to be added to the CANDO library. Using the CANDO Platform we are able to do the hierarchical fragment-based docking with dynamics between those compounds/drugs and the microbiome proteins/proteomes to determine which ones of the drugs and metabolites will work most efficaciously in patients using specific drugs.
Over the last couple of years, We have become increasingly interested in nanomedicine and have developed several interdisciplinary clinical translational research focused collaborations that include 1) Nanotechnology based delivery systems to examine antitretroviral transport across the BBB; 2) Nanotherapeutics using siRNA/Plasmid delivery to specific regions in the brain to target various genes of interest specifically those pertaining to the dopaminergic pathway that includes a phosphor protein called “DARPP-32”. Targeting various key genes in the dopaminergic pathway results in the modulation of behavioral response which we observed in animal models of addiction/depression, 3) Biodistribution studies of various nanotherapeutic formulations using PET small animal imaging. Additionally, We are also focused on exploring epigenetic mechanisms that under drug addiction and mechanisms that underlie oxidative stress in neurodegenerative diseases.