Research Projects

Rationale of the research: Vascular endothelial senescence is a key pathological process and a major, independent risk factor for a spectrum of cardiovascular diseases (CVD) including atherosclerosis and hypertension, which are the most leading causes of death and economic burden globally including India. The tissue destructive vascular senescence is caused by the suppression of an intrinsic CXCR4 signaling that preserves the semipermeable barrier function of vascular endothelium. However, the molecular mechanism suppressing the barrier preserving CXCR4 signaling remain unknown, representing a critical gap in vascular pathology. Scientific objectives: To determine if ADAM17-mediated CXCR4 degradation is the primary pathological mechanism driving unresolved barrier dysfunction and the onset, progression, and exacerbation of human vascular senescence, and whether vascular senescence could be prevented by pharmacological inhibitors of ADAM17. Hypothesis: Based on the strong support of multidimensional (live electrophysiological sensing, molecular assays, AI/ML assisted predictive modeling) preliminary data, the proposed study put forward the novel concept that the unresolved barrier dysfunction promoting the onset, progression, and exacerbation of vascular endothelial senescence is caused by proteolytic degradation of the transmembrane CXCR4 by the metalloprotease ADAM17. Main experiments: The proteolytic effects of ADAM17 on purified CXCR4 and membrane-bound endogenous, CXCR4 in young and senescing, human coronary artery endothelial cells treated with vehicle or ADAM17 inhibitor in vitro will be determined spectrophotometrically, and by western blotting and immunofluorescence staining. The atomic and electronic mechanisms underlying the site-specific proteolytic cleavage of human CXCR4 by ADAM17 will be determined by a computational approach integrated with density functional theory (DFT) and molecular mechanics. Endothelial barrier integrity and function will be quantified by immunofluorescence staining of adherens junction complexes and permeability assays using transwell cell culture inserts, respectively. All materials needed for the proposed project are commercially available, well-established protocols and equipment facility exist for the proposed techniques, and, importantly, scientific backup plans have been designed to ensure the timely and successful achievement of the project’s objectives. Expected Significance: The proposed study would discover ADAM17-mediated CXCR4 degradation as a primary pathological mechanism driving unresolved barrier dysfunction and the onset, progression, and exacerbation of human vascular senescence. Further, it would demonstrate whether pharmacologically inhibiting ADAM17 protects the human vasculature from tissue destructive senescence, providing a safer alternative to investigational antisenescence drugs with potentially fatal adverse effects. The proposed project has structured plans to maximize the impact and reach of the novel discovery that ADAM17-mediated CXCR4 degradation is a primary pathological mechanism driving tissue-destructive human vascular senescence. These consist of SCI indexed peer reviewed publications, conference presentations, educational outreach, public engagement and international social media engagement through the international honorary investigator and PI’s international alumnus network. Moreover, the proposed study has three-level action plan consisting the following for future utilization of research outcomes for social and economic growth benefits; (i) Healthcare system integration through multicentric- patient study to validate ADAM17 as a biomarker for CVD risk screening, (ii) Training and capacity building and (iii) Industry outreach for developing small molecule ADAM17 inhibitor drugs, as detailed in the full proposal.