# Molecular Regulation of Mitochondrial Permeability Transition and its Role in Regulated Necrosis > **NIH NIH R01** · BAYLOR COLLEGE OF MEDICINE · 2022 · $60,560 ## Abstract Project Summary/Abstract Myocardial infarction (MI) and its consequent long term recovery constitutes a majority of heart disease in the United States.1 While the return of blood flow to the heart by reperfusion can be lifesaving, it also induces additional cardiomyocyte death.2,3 Currently, there is no therapeutic intervention that serves as a preventative against cardiomyocyte cell death during ischemia-reperfusion (I/R) injury.17 Thus, new pharmacological agents need to be identified. The long-term objective of this proposal is to reduce cardiomyocyte loss during I/R injury to reduce overall mortality and diminish the onset of heart failure following MI. To accomplish this goal, we are investigating two forms of cell death: mitochondrial permeability transition pore (MPTP)- dependent necrosis and ferroptosis, which contribute to ischemia reperfusion (I/R) injury.5,6 During MPTP- dependent necrosis, lethal amounts of radical oxygen species (ROS) and calcium (Ca2+) are thought to open an inner mitochondrial pore known as the MPTP in an unknown mechanism, which causes a loss of mitochondrial membrane potential resulting in myocyte necrotic death.7,8,9,10 Alternatively, in ferroptosis, excess iron (Fe2+) within mitochondria generates ROS which dysregulates lipid membranes in a process known as lipid peroxidation (LIPOX).11,12,13 In previous studies, individual pharmacological inhibition of both mechanisms demonstrated a promising reduction of infarct size in mice.14,15 Unfortunately, clinical trials targeting the MPTP- dependent pathway were not successful in humans, suggestive that cell death during I/R injury is more complex than anticipated.16 Therefore, our research strategy will address if dually targeting these mechanisms simultaneously can further reduce infarct size post I/R injury. Our preliminary data suggests that pathway initiation depends on ROS concentration and Ca2+ availability, as low concentrations of ROS are able to sensitize Ca2+-dependent MPTP opening, whereas high ROS levels can lead to mitochondrial dysfunction via LIPOX. We also determined that targeting both pathways in vitro was additively protective against ROS- induced cell death, achieved by treating ferroptosis inhibitor ferrostatin-1 on a genetic knock-out cell line of MPTP regulator cyclophilin D (CypD). Therefore, we hypothesize that dual inhibition of MPTP-dependent necrosis and ferroptosis pathways will be additively protective against myocardial I/R injury. In Aim 1, we will challenge isolated heart mitochondria with I/R-relevant insults such as Ca2+, Fe2+, or ROS to mechanistically examine pathway induction. In Aim 2, we will therapeutically target both MPTP-dependent necrosis and ferroptosis pathways using both pharmaceutical and genetic strategies. We will use MPTP inhibitor cyclosporine A and LIPOX inhibitor ferrostatin-1 in combination against I/R, as well as perform adeno- associated viral (AAV) overexpression of anti-ferroptotic antioxidant GPX4 on geneti... ## Key facts - **NIH application ID:** 10630723 - **Project number:** 3R01HL150031-03S1 - **Recipient organization:** BAYLOR COLLEGE OF MEDICINE - **Principal Investigator:** Jason Michael Karch - **Activity code:** R01 (R01, R21, SBIR, etc.) - **Funding institute:** NIH - **Fiscal year:** 2022 - **Award amount:** $60,560 - **Award type:** 3 - **Project period:** 2022-09-01 → 2025-06-30 ## Primary source NIH RePORTER: https://reporter.nih.gov/project-details/10630723 ## Citation > US National Institutes of Health, RePORTER application 10630723, Molecular Regulation of Mitochondrial Permeability Transition and its Role in Regulated Necrosis (3R01HL150031-03S1). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10630723. Licensed CC0. --- *[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*