R01HL152133

Enhancing Endothelial Cell Engraftment via Transplantation of Exogenous Mitochondria - Project Summary/Abstract

Ischemic diseases, including critical limb ischemia and myocardial infarction, afflict millions of people in the United States. Currently, these diseases are predominantly treated by surgical interventions. However, the inability to regenerate microvascular beds in ischemic tissues remains a challenge. Alternatively, the development of therapies based on transplanting endothelial cells (ECs) continues to be a priority in vascular medicine.

Unfortunately, engrafting ECs is not trivial. Studies have repeatedly shown that in order to achieve significant engraftment resulting in functional new blood vessels, ECs require co-transplantation with supporting cells such as mesenchymal stromal cells (MSCs). However, this paradigm is problematic because it increases the complexity of clinical trials exponentially.

Previously, we have published extensively on all aspects of human EC+MSC engraftment. However, the underlying mechanisms by which MSCs facilitate EC engraftment remain incompletely understood. Recently, we found that upon implantation, MSCs transfer mitochondria to ECs via tunneling nanotubes and that when this transfer was genetically abrogated, EC engraftment was drastically impaired.

Based on this insight, we propose a new concept: artificially transplanting mitochondria into human ECs as a means to preemptively enhance their ability to engraft without a secondary cell type. Indeed, our preliminary data show that transplanting exogenous mitochondria into ECs renders the cells (termed mitot-ECs) capable of forming functional vessels in vivo in ischemic tissues, without the support of MSCs. We also found that transplanted mitochondria co-localized with LC3B-marked autophagosomes and that genetic ablation of PINK1 and Parkin (both central players in mitophagy) eliminated the enhanced engraftment ability of mitot-ECs.

Together, our overarching hypothesis is that transplanting exogenous mitochondria into ECs renders transient cytoprotection via mitophagy; this, in turn, enhances the engraftment ability of the cells. To test this hypothesis and to determine the efficacy of mitot-ECs to treat ischemic diseases, we propose two specific aims.

In Aim 1, we will determine conditions (e.g., concentration and timing) for optimal EC engraftment in immunodeficient mice. We will dissect the role of mitophagy and will examine the fate and persistence of the transplanted mitochondria. We will also determine if selective drugs with mitophagy-enhancing properties could also enhance EC engraftment.

In Aim 2, we will determine the efficacy of mitochondrial transplantation-enabled EC therapy in two well-established models of ischemic diseases: critical hind limb ischemia (in mice) and myocardial ischemia/reperfusion injury (in rats).

In summary, we propose studies to develop a novel approach to engraft ECs more successfully. We envision this research could become the basis for a new strategy in vascular cell therapies.

Children's Hospital Corporation

<P>THE GOALS ARE:</P><UL><LI>TO FOSTER FUNDAMENTAL CREATIVE DISCOVERIES, INNOVATIVE RESEARCH STRATEGIES, AND THEIR APPLICATIONS AS A BASIS FOR ULTIMATELY PROTECTING AND IMPROVING HEALTH;</LI><LI>TO DEVELOP, MAINTAIN, AND RENEW SCIENTIFIC HUMAN AND PHYSICAL RESOURCES THAT WILL ENSURE THE NATION'S CAPABILITY TO PREVENT DISEASE;</LI><LI>TO EXPAND THE KNOWLEDGE BASE IN MEDICAL AND ASSOCIATED SCIENCES IN ORDER TO ENHANCE THE NATION'S ECONOMIC WELL-BEING AND ENSURE A CONTINUED HIGH RETURN ON THE PUBLIC INVESTMENT IN RESEARCH; AND</LI><LI>TO EXEMPLIFY AND PROMOTE THE HIGHEST LEVEL OF SCIENTIFIC INTEGRITY, PUBLIC ACCOUNTABILITY, AND SOCIAL RESPONSIBILITY IN THE CONDUCT OF SCIENCE.</LI></UL><P>IN REALIZING THESE GOALS, THE NIH PROVIDES LEADERSHIP AND DIRECTION TO PROGRAMS DESIGNED TO IMPROVE THE HEALTH OF THE NATION BY CONDUCTING AND SUPPORTING RESEARCH:</P><UL><LI>IN THE CAUSES, DIAGNOSIS, PREVENTION, AND CURE OF HUMAN DISEASES;</LI><LI>IN THE PROCESSES OF HUMAN GROWTH AND DEVELOPMENT;</LI><LI>IN THE BIOLOGICAL EFFECTS OF ENVIRONMENTAL CONTAMINANTS;</LI><LI>IN THE UNDERSTANDING OF MENTAL, ADDICTIVE AND PHYSICAL DISORDERS; AND</LI><LI>IN DIRECTING PROGRAMS FOR THE COLLECTION, DISSEMINATION, AND EXCHANGE OF INFORMATION IN MEDICINE AND HEALTH, INCLUDING THE DEVELOPMENT AND SUPPORT OF MEDICAL LIBRARIES AND THE TRAINING OF MEDICAL LIBRARIANS AND OTHER HEALTH INFORMATION SPECIALISTS.</LI></UL>

93.837 - Cardiovascular Diseases Research

National Heart Lung and Blood Institute (NHLBI) [HHS - NIH]

Boston, Massachusetts 021155724 United States

Single Zip Code

NIH Research Project Grant (Parent R01 Clinical Trial Not Allowed) (PA-25-301)

Amendment Since initial award the End Date has been extended from 11/30/24 to 02/28/30 and the total obligations have increased 535% from $480,029 to $3,049,649.