Almost 30% of survivors of myocardial infarction (MI) develop heart failure (HF), in part due to damage caused by the accumulation of dysfunctional mitochondria. Organelle quality control through Parkin-mediated mitochondrial autophagy (mitophagy) is known to play a role in mediating protection against HF damage post-ischaemic injury and remodelling of the subsequent deteriorated myocardium. This study has shown that a single i.p. dose (2 h post-MI) of the selective small molecule Parkin activator PR-364 reduced mortality, preserved cardiac ejection fraction, and mitigated the progression of HF. To reveal the mechanism of PR-364, a multi-omic strategy was deployed in combination with classical functional assays using in vivo MI and in vitro cardiomyocyte models. In vitro cell data indicated that Parkin activation by PR-364 increased mitophagy and mitochondrial biogenesis, enhanced adenosine triphosphate production via improved citric acid cycle, altered accumulation of calcium localization to the mitochondria, and initiated translational reprogramming with increased expression of mitochondrial translational proteins. In mice, PR-364 administered post-MI resulted in widespread proteome changes, indicating an up-regulation of mitochondrial metabolism and mitochondrial translation in the surviving myocardium. This study demonstrates the therapeutic potential of targeting Parkin-mediated mitophagy using PR-364 to protect surviving cardiac tissue post-MI from progression to HF. Parkin activator proposed therapeutic mechanisms. Inactive Parkin (red) is activated by PR-364; activated Parkin (green) promotes enhanced mitophagy and mito-biogenesis, improves mitochondrial function via increased mitochondrial calcium level and biogenesis, and ultimately leads to limited post-myocardial infarction cardiac remodelling and heart failure. MI, myocardial infarction.

Coxsackievirus B (CVB) is a common human enterovirus that causes systemic infection but specifically replicates to high titers in the pancreas. It was reported that certain viruses induce mitochondrial fission to support infection. We documented that CVB triggers mitochondrial fission and blocking mitochondrial fission limits infection. The transient receptor potential channels have been implicated in regulating mitochondrial dynamics; namely, the heat and capsaicin receptor transient receptor potential cation channel subfamily V member 1 (TRPV1) contributes to mitochondrial depolarization and fission. When we transiently warmed HeLa cells to 39 °C prior to CVB exposure, infection was heightened, whereas cooling cells to 25 °C reduced infection. Inducing “cold” by stimulating transient receptor potential cation channel subfamily M member 8 (TRPM8) with menthol led to reduced infection and also resulted in lower levels of mitochondrial fission during infection. Additionally, menthol stabilized levels of mitochondrial antiviral signaling (MAVS) which is known to be tied to mitochondrial dynamics. Taken together, this highlights a novel pathway wherein CVB relies on TRPV1 to initiate proviral mitochondrial fission, which may contribute to the disruption of antiviral immunity. TRPM8 has been shown to antagonize TRPV1, and thus we hypothesize that stimulating TRPM8 blocks TRPV1-mediated mitochondrial fragmentation following CVB exposure and attenuates infection.

Cardiovascular disease is the main cause of death worldwide, making it crucial to search for new therapies to mitigate major adverse cardiac events (MACEs) after a cardiac ischemic episode. Drugs in the class of the glucagon-like peptide-1 receptor agonists (GLP1Ra) have demonstrated benefits for heart function and reduced the incidence of MACE in patients with diabetes. Previously, we demonstrated that a short-acting GLP1Ra known as DMB (2-quinoxalinamine, 6,7-dichloro-N-[1,1-dimethylethyl]-3-[methylsulfonyl]-,6,7-dichloro-2-methylsulfonyl-3-N-tert-butylaminoquinoxaline or compound 2, Sigma) also mitigates adverse postinfarction left ventricular remodeling and cardiac dysfunction in lean mice through activation of parkin-mediated mitophagy following infarction. Here, we combined proteomics with in silico analysis to characterize the range of effects of DMB in vivo throughout the course of early postinfarction remodeling. We demonstrate that the mitochondrion is a key target of DMB and mitochondrial respiration, oxidative phosphorylation and metabolic processes such as glycolysis and fatty acid beta-oxidation are the main biological processes being regulated by this compound in the heart. Moreover, the overexpression of proteins with hub properties identified by protein–protein interaction networks, such as Atp2a2, may also be important to the mechanism of action of DMB. Data are available via ProteomeXchange with identifier PXD027867.

Myocardial-Infarction (MI) remains a leading cause of mortality worldwide, despite advancements in clinical therapies and interventions. MI results from prolonged ischemia, leading to hypoxia-induced damage to cardiac tissue and reperfusion-injury (R/I) that aggravates cardiomyocyte (CM) loss. One key cellular event during this process is the accumulation of dysfunctional mitochondria, resulting from environmental hypoxia and subsequent oxidative stress upon reperfusion. Post-MI cardiac-remodeling involves changes in both cellular and extracellular matrix (ECM). Ubiquitin-dependent and independent autophagy are crucial for cardio-protection during this phase. Asporin (ASPN), a small leucine-rich proteoglycan, modulates cardiac remodeling by limiting excessive fibrosis and protecting CMs from cell death. We investigated the therapeutic potential of ASPN using an exogenous recombinant ASPN-peptide (rASPN) and tested its effects in an in-vitro ischemia-reperfusion (I/R) model simulating MI conditions. Two I/R models were developed using an immortalized human embryonic cardiac cell line to reflect the hypoxia-reperfusion (H/R) phases of MI. In the No-Reoxygenation (No-ReOx) model, cells were subjected to hypoxia for 18-hours, with or without exogenous rASPN. In the Reoxygenation (ReOx) model, cells underwent 18-hours of hypoxia, followed by 12-hours of reoxygenation (simulating reperfusion), with or without rASPN. Proteomics revealed that ASPN modulates pathways involved in apoptosis, non-canonical autophagy, and metabolic reprogramming. Additionally, ASPN influenced immune-response pathways and significantly affected TGF-β signaling, a central mediator of cardiac fibrosis and remodeling post-MI. Our study demonstrates that rASPN confers protection in a human cardiac cell-based H/R model, highlighting its therapeutic potential as a biological or peptide-based intervention to mitigate R/I and adverse remodeling following MI.