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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.

Hypothermia is a valuable clinical tool in mitigating against the consequences of ischemia in surgery, stroke, cardiac arrest and organ preservation. Protection is afforded principally by a reduction of metabolism, manifesting as reduced rates of oxygen uptake, preservation of ATP levels, and a curtailing of ischemic calcium overload. The effects of non-ischemic hypothermic stress are relatively unknown. We sought to investigate the effects of clinically mild-to-severe hypothermia on mitochondrial morphology, oxygen consumption and protein expression in normoxic hearts and cardiac cells. Normoxic perfusion of rat hearts at 28–32 °C was associated with inhibition of mitochondrial fission, evidenced by a reduced abundance of the active phosphorylated form of the fission receptor Drp1 (pDrp1S616). Abundance of the same residue was reduced in H9c2 cells subjected to hypothermic culture (25–32 °C), in addition to a reduced abundance of the Drp1 receptor MFF. Hypothermia-treated H9c2 cardiomyocytes exhibited elongated mitochondria and depressed rates of mitochondrial-associated oxygen consumption, which persisted upon rewarming. Hypothermia also promoted a reduction in mRNA expression of the capsaicin receptor TRPV1 in H9c2 cells. When normothermic H9c2 cells were transfected with TRPV1 siRNA we observed reduced pDrp1S616 and MFF abundance, elongated mitochondria, and reduced rates of mitochondrial-associated oxygen consumption, mimicking the effects of hypothermic culture. In conclusion hypothermia promoted elongation of cardiac mitochondria via reduced pDrp1S616 abundance which was also associated with suppression of cellular oxygen consumption. Silencing of TRPV1 in H9c2 cardiomyocytes reproduced the morphological and respirometric phenotype of hypothermia. This report demonstrates a novel mechanism of cold-induced inhibition of mitochondrial fission.

Antimicrobial-resistant and novel pathogens continue to emerge, outpacing efforts to contain and treat them. Therefore, there is a crucial need for safe and effective therapies. Ultraviolet-A (UVA) phototherapy is FDA-approved for several dermatological diseases but not for internal applications. We investigated UVA effects on human cells in vitro, mouse colonic tissue in vivo, and UVA efficacy against bacteria, yeast, coxsackievirus group B and coronavirus-229E. Several pathogens and virally transfected human cells were exposed to a series of specific UVA exposure regimens. HeLa, alveolar and primary human tracheal epithelial cell viability was assessed after UVA exposure, and 8-Oxo-2'-deoxyguanosine was measured as an oxidative DNA damage marker. Furthermore, wild-type mice were exposed to intracolonic UVA as an in vivo model to assess safety of internal UVA exposure. Controlled UVA exposure yielded significant reductions in Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Enterococcus faecalis, Clostridioides difficile, Streptococcus pyogenes, Staphylococcus epidermidis, Proteus mirabilis and Candida albicans. UVA-treated coxsackievirus-transfected HeLa cells exhibited significantly increased cell survival compared to controls. UVA-treated coronavirus-229E-transfected tracheal cells exhibited significant coronavirus spike protein reduction, increased mitochondrial antiviral-signaling protein and decreased coronavirus-229E-induced cell death. Specific controlled UVA exposure had no significant effect on growth or 8-Oxo-2'-deoxyguanosine levels in three types of human cells. Single or repeated in vivo intraluminal UVA exposure produced no discernible endoscopic, histologic or dysplastic changes in mice. These findings suggest that, under specific conditions, UVA reduces various pathogens including coronavirus-229E, and may provide a safe and effective treatment for infectious diseases of internal viscera. Clinical studies are warranted to further elucidate the safety and efficacy of UVA in humans.

Given that adverse remodeling is the leading cause of heart failure and death in the USA, there is an urgent unmet need to develop new methods in dealing with this devastating disease. Here we evaluated the efficacy of a short-course glucagon-like peptide-1 receptor agonist therapy—specifically 2-quinoxalinamine, 6,7-dichloro-N-(1,1-dimethylethyl)-3-(methylsulfonyl)-,6,7-dichloro-2-methylsulfonyl-3-N-tert-butylaminoquinoxaline (DMB; aka Compound 2) – in attenuating adverse LV remodeling. We also examined the role, if any, of mitochondrial turnover in this process. Wild-type, Parkin knockout and MitoTimer-expressing mice were subjected to permanent coronary artery ligation, then treated briefly with DMB. LV remodeling and cardiac function were assessed by histology and echocardiography. Autophagy and mitophagy markers were examined by western blot and mitochondrial biogenesis was inferred from MitoTimer protein fluorescence and qPCR. We found that DMB given post-infarction significantly reduced adverse LV remodeling and the decline of cardiac function. This paralleled an increase in autophagy, mitophagy and mitochondrial biogenesis. The salutary effects of the drug were lost in Parkin knockout mice, implicating Parkin-mediated mitophagy as part of its mechanism of action. Our findings suggest that enhancing Parkin-associated mitophagy and mitochondrial biogenesis after infarction is a viable target for therapeutic mitigation of adverse remodeling.

Summary Atrial fibrillation (AF) is the most common arrhythmia after cardiac surgery. From a pathophysiological point of view, a myriad of factors such as trauma, atrial dilation, ischemia, mechanical myopericarditis, autonomic imbalance, loss of connexins, AF nest remodeling, inflammation, sutures, and dysfunction caused by postextracorporeal circulation can contribute to postoperative atrial fibrillation (POAF) resulting in a longer hospital stay and consequently higher cost. Recent studies showed that short fragments of RNA, called microRNA (miRNA), can contribute to the development of several cardiovascular diseases, including AF. The aim of this study was to evaluate the levels of circulating miRNAs (miR-1, -23a, and -26a) that can be involved in POAF. Patients submitted to coronary artery bypass graft surgery were grouped in POAF (24 patients) and without POAF (24 patients). Results showed older age, longer clamp-time, and more days in the intensive care unit as well as a longer total hospital stay in the POAF group. Preoperative levels of circulating miRNAs were similar. Analysis of miRNAs revealed significantly lower circulating levels of miRNA-23a (P = 0.02) and -26a (P = 0.01) in the POAF group during the postoperative period. Receiver operating characteristic (ROC) analysis showed the area under the ROC curve of miR-23a and miR-26a for predicting FA was 0.63 (95% confidence interval [CI]: 0.51–0.74; P = 0.02) and 0.66 (95% CI: 0.55–0.77; P = 0.01), respectively. Our data suggests that circulating miRNA-23a and -26a may be involved in the underlying biology of postoperative AF development.

BackgroundAbdominal aortic aneurysm (AAA) is a pathological enlargement of infrarenal aorta close to the aortic bifurcation, and it is an important cause of mortality in the elderly. Therefore, the biomarker identification for early diagnosis is of great interest for clinical benefit. It is known that microRNAs (miRNAs) have important roles via target genes regulation in many diseases. This study aimed to identify miRNAs and their target genes involved in the pathogenesis of AAA.MethodsTissue samples were obtained from patients who underwent AAA surgery and from organ donors (control group). Quantitative PCR Array was applied to assess 84 genes and 384 miRNAs aiming to identify differentially expressed targets (AAA n = 6, control n = 6), followed by validation in a new cohort (AAA n = 18, control n = 6) by regular qPCR. The functional interaction between validated miRNAs and target genes was performed by the Ingenuity Pathway Analysis (IPA) software.ResultsThe screening cohort assessed by PCR array identified 10 genes and 59 miRNAs differentially expressed (≥2-fold change, pConclusionPaired interactions of differentially expressed ALOX5, PTGIS, CX3CL1 genes, and miR-193b-3p, 125b-5p, 150-5p revealed a potentially significant role of the eicosanoid synthesis and metalloproteinase/TIMP pathways in the AAA pathogenesis.

Pioglitazone (PIO) and GLP-1R receptor agonist (GLP1Ra) have been shown to be cardioprotective against ischemic cardiac injury. Much less is known about the effects of these agents on adverse post-MI LV remodeling. Based on our earlier findings that PIO and a GLP1Ra stimulate mitochondrial turnover, we evaluated the effects of these agents on post-MI remodeling. Lean mice underwent permanent coronary artery ligation (PCAL) to ensure that remodeling would be independent of changes in infarct size. Vehicle, PIO and GLP1Ra (Sigma) were administered i.p. 2h after the infarct and then every other day for a total of 6 doses. Echo and histology (Masson’s trichrome) were used to assess LV remodeling 30 days post-MI (late phase); immune cell infiltration was assessed 7 days after PCAL (early phase) via hematoxylin and eosin (H&E) staining. Both PIO and GLP1Ra were associated with significant improvements in ejection fraction and fractional shortening (A); however, at the dose used, neither drug restored function to that of the sham-operated mice (EF 60% and FS 30%, data not shown). GLP1Ra-treated mice exhibited a marked reduction in immune cell infiltration at 7d after PCAL (B), and fibrosis at 30d (C) compared to vehicle or PIO. While PIO had no effect on immune-cell infiltration and fibrosis, it was effective in attenuating post-MI remodeling. While sharing a common endpoint of attenuating adverse remodeling, the finding that PIO stimulates mitochondrial biogenesis and GLP1Ra induces mitophagy may help explain their disparate findings with respect to early phase remodeling.

MicroRNAs (miRs) regulate post-transcriptional gene expression and protein translation. There is now increasing evidence that miRs regulate mitochondrial turnover. miR-33 regulates cholesterol metabolism and mitochondrial function in cardiac fibroblasts and macrophages and has been implicated in promoting fibrosis. Excessive fibrosis contributes to the development of adverse LV remodeling. Given our recent findings that a glucagon-like peptide-1 receptor agonist (GLP1Ra) [Sigma] induces mitophagy and mitigates post-MI LV remodeling, the purpose of this study was to determine its effects on miR-33 expression after MI. We analyzed miR-33 expression in the viable regions of hearts in lean mice after permanent coronary arterial ligation (PCAL) and subsequent treatment with GLP1Ra administered 2h and 48h after the infarction (total of 2 doses). PCAL was associated with a marked increase in miR-33 that peaked at day 3 (data not shown). In the presence of GLP1Ra, miR-33 expression was suppressed 3 days post-PCAL ( A ). Polysome profiling revealed that miR-33 was decreased in the translating fractions of GLP1Ra-treated mice and increased in the non-translating fraction (80S free ribosomes) compared to vehicle ( B and C ). Decreased association of miR-33 with polysomes in GLP1Ra-treated mice would allow for increased target translation. Given that suppression of miR-33 is implicated in promoting fibrosis, a suppression of this miR by acute GLP1Ra treatment could explain the beneficial effects of this drug in limiting adverse cardiac remodeling.

Background During pancreatitis, autophagy is activated, but lysosomal degradation of dysfunctional organelles including mitochondria is impaired, resulting in acinar cell death. Retrospective cohort analyses demonstrated an association between simvastatin use and decreased acute pancreatitis incidence. Methods We examined whether simvastatin can protect cell death induced by cerulein and the mechanisms involved during acute pancreatitis. Mice were pretreated with DMSO or simvastatin (20 mg/kg) for 24 h followed by 7 hourly cerulein injections and sacrificed 1 h after last injection to harvest blood and tissue for analysis. Results Pancreatic histopathology revealed that simvastatin reduced necrotic cell death, inflammatory cell infiltration and edema. We found that cerulein triggered mitophagy with autophagosome formation in acinar cells. However, autophagosome-lysosome fusion was impaired due to altered levels of LAMP-1, AMPK and ULK-1, resulting in autophagosome accumulation (incomplete autophagy). Simvastatin abrogated these effects by upregulating LAMP-1 and activating AMPK which phosphorylated ULK-1, resulting in increased formation of functional autolysosomes. In contrast, autophagosomes accumulated in control group during pancreatitis. The effects of simvastatin to promote autophagic flux were inhibited by chloroquine. Mitochondria from simvastatin-treated mice were resistant to calcium overload compared to control, suggesting that simvastatin induced mitochondrial quality control to eliminate susceptible mitochondria. Clinical specimens showed a significant increase in cell-free mtDNA in plasma during pancreatitis compared to normal controls. Furthermore, genetic deletion of parkin abrogated the benefits of simvastatin. Conclusion Our findings reveal the novel role of simvastatin in enhancing autophagic flux to prevent pancreatic cell injury and pancreatitis.