Excellence in Research: Bioengineered extracellular vesicles from stem cells and macrophages act synergistically in angiogenesis

Morehouse School Of Medicine, Atlanta GA

Investigators

Abstract

Extracellular vesicles (EVs) are cell-released microparticles that play essential roles in cell-cell communication by delivering their cargo. Traditional approaches to studying EVs have focused on investigating EVs derived from individual cell types, disregarding the likelihood that EVs are secreted by all cell types and coexist in various extracellular fluids in the body. This project introduces an innovative exploration of the collaborative effects of EVs from diverse sources in promoting the formation of blood vessels. Additionally, the EV cells will be modified through bioengineering techniques to enhance the production and proangiogenic (blood vessel forming) activities of EVs. Successful completion of this project will advance our understanding in two key areas: 1) the cooperative actions of EVs from different cell types in normal physiological processes and pathological responses, and 2) the exploration of novel therapeutic strategies utilizing EVs derived from multiple sources in combination. Furthermore, an integrated education plan is designed to increase the participation of students from groups traditionally underrepresented in science. This project will provide students with research training in the implementation and analysis of each objective and with intramural and extramural opportunities to present their findings. The outcomes of this project will be scholarly disseminated via publication and conference presentations and will be incorporated into existing courses related to the formation of blood vessels. Angiogenesis is a tightly regulated process essential for embryonic development and the maintenance of vascular homeostasis in adult organisms. Stem cells and macrophages are involved in the regulation of angiogenesis via cell differentiation and factor secretion. Recently, vesicles secreted from the cells have been implicated in the array of mediators in the angiogenic processes. Two primary classes of non-apoptotic vesicles, exosomes and microvesicles, released by cells are categorized as EVs. Unlike living cells, EVs are submicron vesicles that target recipient cells to deliver their cargo, including RNAs, proteins, and lipids, in a cell-free fashion. Previous literature has demonstrated that certain microRNAs (miRs) are involved in angiogenesis, so-called AngiomiRs. The objectives of this project are to investigate the synergistic effects of EVs from mouse mesenchymal stem cells and macrophages on angiogenesis in vitro and in vivo. The stem cells and macrophages will be engineered beforehand to overexpress miR-31 and miR-30, respectively, based on previous reports. The in vitro angiogenic effects of a mixture of the EVs released from the two types of engineered cells will be examined on vascular endothelial cells including proliferation, migration, and tube formation in comparison with either type of EVs. To further explore the function of neovasculature, the angiogenic effects of the mixture of the two engineered EVs will be investigated in a mouse hindlimb ischemia (HLI) model. Moreover, the synergistic roles of miR-31/FIH1 and miR-30/Cul2 signaling pathways on HIF-1α transactivation, an essential step in proangiogenesis, will be tested. The result of this study will be a comprehensive understanding of how diverse EVs regulate angiogenesis. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.