MicroRNA-425 as an angiogenic regulator in diabetic critical limb ischemia

• Grant number: 22/01538-3
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: August 29, 2022
• End date: August 28, 2023
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Fernanda Loureiro de Andrade Orsi
• Grantee: Camila de Oliveira Vaz
• Supervisor: Mark Feinberg
• Host Institution: Faculdade de Ciências Médicas (FCM). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Institution abroad: Harvard University, Boston, United States
• Associated to the scholarship: 20/07922-4 - Validation and derivation of serum microRNA panel as biomarkers of COVID-19 severe forms, BP.DR

Abstract

Peripheral artery disease (PAD) is characterized by numbness, swelling, and pain of the extremities that occurs after brief periods of walking or exercise. Approximately 2% of patients afflicted with PAD will experience worsening symptoms and develop Critical Limb Ischemia (CLI), characterized by its intense claudication and high risk for amputation and cardiovascular complications. Within the group of patients who develop CLI, individuals with type 2 diabetes are disproportionally represented. The primary cause of PAD and CLI is a progressive narrowing of the arteries due to atherosclerosis, resulting in reduced blood flow. As a result, endothelial cell (EC) dysfunction, impaired angiogenesis, and dysregulated inflammatory responses are primary contributors to these diseases. However, our knowledge of the molecular underpinnings of the relationship between diabetes and CLI remains poorly defined. Of these signaling events, disease-associated changes in microRNA (miRNA) signaling have been implicated to occur prior to or at disease onset. Because miRNAs exhibit high conservation across species, sequencing of miRNAs from plasma of human patients with PAD and mice experiencing limb ischemia was used to identify overlapping miRNA targets and discovered a top candidate miR-425. Preliminary in vitro data utilizing miR-425 mimics in ECs revealed that overexpression accelerates EC wound closure, spheroid sprouting, and network tube formation. In addition, ECs exposed to high glucose downregulated miR-425 and co-transfection of miR-425 with high glucose conditions accelerated closure. Our pilot studies show that therapeutic delivery of miR-425 improved blood flow recovery and limb necrosis after femoral artery ligation in diabetic mice. These exciting findings provide the basis for the central hypothesis that miR-425 promotes limb perfusion and alleviates ischemic injury in diabetic CLI. In Aim 1, we will identify the molecular targets of miR-425 that facilitate angiogenesis. In Aim 2, we will evaluate the therapeutic potential of miR-425 in a critical limb ischemia model in diabetic mice. Finally, in Aim 3 we will assess miR-425 expression in plasma samples from CLI patients with increasing disease severity. The proposed studies coupled with early career learning opportunities will provide the applicant with a unique scientific endeavor to understand the role of miRNA-mediated control of angiogenesis in diabetic limb ischemia. (AU)