Periodic Reporting for period 4 - PROVASC (Cell-specific vascular protection by CXCL12/CXCR4)
Periodo di rendicontazione: 2021-04-01 al 2023-03-31
To balance the ongoing expansion of genetic risk variants, we aim to discover and elucidate new mechanisms for protective cell homeostasis and regeneration counteracting atherosclerosis.
To pursue and achieve this goal in depth, PROVASC will
● dissect cell-specific effects of the CXCR4-CXCL12 axis using an array of mouse lines for conditionnal deletion or bone marrow chimeras to compare resident vs hematopoietic cell compartments.
● validate a role of coding and non-coding genetic risk variants affecting CXCL12 and CXCR4 in different human cell types and humanized mouse models.
● unravel an epigenetic regulation of CXCL12/CXCR4 through cell type-specific microRNAs by identifying relevant microRNAs and targeting sites controlling this axis.
Given the ubiquitous relevance of CXCL12/CXCR4, we expect that the impact of such new mechanisms will extend beyond atherosclerosis to other chronic inflammatory diseases, allowing for tailored strategies of tissue protection and regeneration.
Most importantly, we have screened and validated miRNAs that target and regulate the CXCR4/CXCL12 axis (Cimen et al., under review after revision). Given its crucial role CXCR4 in ECs or VSMCs for vascular integrity, yet atherogenic functions in other cell types, strategies for cell-specifically augmenting CXCR4 function are critical for employing this receptor for therapeutic purposes. Here, we identified miR-206-3p as a vascular-specific CXCR4 repressor and exploited a target-site blocker (CXCR4-TSB) disrupting this interaction to therapeutically increase CXCR4 in the vessel wall. In vitro, CXCR4-TSB enhanced CXCR4 expression in human and murine ECs and VSMCs to promote beneficial effects on cell viability, proliferation, and migration. Systemic administration of CXCR4-TSB in Apoe-deficient mice enhanced Cxcr4 expression in ECs and VSMCs in the vessel wall, reduced vascular permeability and monocyte adhesion to endothelium, and attenuated the development of diet-induced athero-sclerosis. Notably, CXCR4-TSB also affected CXCR4 expression in B cells corroborating its atheroprotective role in this cell type. Analyses of human atherosclerotic plaques revealed a negative correlation between CXCR4 and miR-206-3p, supporting the conservation of this axis in human disease. The disruption of cell-specific microRNA-dependent regulatory pathways, as epitomized by the miR-206-3p-CXCR4 axis, reveals a novel therapeutic approach, and paves the way for a tailored use of TSBs in the treatment of atherosclerosis and other diseases. These data have been submitted in a thoroughly revised manuscript currently under final review for publication.