Genetic potential for changes in breeding systems: Predicted and observed trait changes during artificial selection for male and female allocation in a gynodioecious species.

PREMISE: Evolution of separate sexes from hermaphroditism often proceeds through gynodioecy, but genetic constraints on this process are poorly understood. Genetic (co-)variances and between-sex genetic correlations were used to predict evolutionary responses of multiple reproductive traits in a sexually dimorphic gynodioecious species, and predictions were compared with observed responses to artificial selection. METHODS: Schiedea (Caryophyllaceae) is an endemic Hawaiian lineage with hermaphroditic, gynodioecious, subdioecious, and dioecious species. We measured genetic parameters of Schiedea salicaria and used them to predict evolutionary responses of 18 traits in hermaphrodites and females in response to artificial selection for increased male (stamen) biomass in hermaphrodites or increased female (carpel, capsule) biomass in females. Observed responses over two generations were compared with predictions in replicate lines of treatments and controls. RESULTS: In only two generations, both stamen biomass in hermaphrodites and female biomass in females responded markedly to direct selection, supporting a key assumption of models for evolution of dioecy. Other biomass traits, pollen and ovule numbers, and inflorescence characters important in wind pollination evolved indirectly in response to selection on sex allocation. Responses generally followed predictions from multivariate selection models, with some responses unexpectedly large due to increased genetic correlations as selection proceeded. CONCLUSIONS: Results illustrate the power of artificial selection and utility of multivariate selection models incorporating sex differences. They further indicate that pollen and ovule numbers and inflorescence architecture could evolve in response to selection on biomass allocation to male versus female function, producing complex changes in plant phenotype as separate sexes evolve.

Association of Physical Activity With Bioactive Lipids and Cardiovascular Events.

BACKGROUND: To clarify the mechanisms underlying physical activity (PA)-related cardioprotection, we examined the association of PA with plasma bioactive lipids (BALs) and cardiovascular disease (CVD) events. We additionally performed genome-wide associations. METHODS: PA-bioactive lipid associations were examined in VITAL (VITamin D and OmegA-3 TriaL)-clinical translational science center (REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT01169259; N=1032) and validated in JUPITER (Justification for the Use of statins in Prevention: an Intervention Trial Evaluating Rosuvastatin)-NC (REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT00239681; N=589), using linear models adjusted for age, sex, race, low-density lipoprotein-cholesterol, total-C, and smoking. Significant BALs were carried over to examine associations with incident CVD in 2 nested CVD case-control studies: VITAL-CVD (741 case-control pairs) and JUPITER-CVD (415 case-control pairs; validation). RESULTS: We detected 145 PA-bioactive lipid validated associations (false discovery rate <0.1). Annotations were found for 6 of these BALs: 12,13-diHOME, 9,10-diHOME, lysoPC(15:0), oxymorphone-3b-D-glucuronide, cortisone, and oleoyl-glycerol. Genetic analysis within JUPITER-NC showed associations of 32 PA-related BALs with 22 single-nucleotide polymorphisms. From PA-related BALs, 12 are associated with CVD. CONCLUSIONS: We identified a PA-related bioactive lipidome profile out of which 12 BALs also had opposite associations with incident CVD events.

Asporin, an extracellular matrix protein, is a beneficial regulator of cardiac remodeling.

Heart failure is accompanied by adverse cardiac remodeling involving extracellular matrix (ECM). Cardiac ECM acts as a major reservoir for many proteins including growth factors, cytokines, collagens, and proteoglycans. Activated fibroblasts during cardiac injury can alter the composition and activity of these ECM proteins. Through unbiased analysis of a microarray dataset of human heart tissue comparing normal hearts (n = 135) to hearts with ischemic cardiomyopathy (n = 94), we identified Asporin (ASPN) as the top differentially regulated gene (DEG) in ischemic cardiomyopathy; its gene-ontology terms relate closely to fibrosis and cell death. ASPN is a Class I small leucine repeat protein member implicated in cancer, osteoarthritis, and periodontal ligament mineralization. However, its role in cardiac remodeling is still unknown. Here, we initially confirmed our big dataset analysis through cells, mice, and clinical atrial biopsy samples to demonstrate increased Aspn expression after pressure overload or cardiac ischemia/reperfusion injury. We tested the hypothesis that Aspn, being a TGFß1 inhibitor, can attenuate fibrosis in mouse models of cardiac injury. We found that Aspn is released by cardiac fibroblasts and attenuates TGFß signaling. Moreover, Aspn-/- mice displayed increased fibrosis and decreased cardiac function after pressure overload by transverse aortic constriction (TAC) in mice. In addition, Aspn protected cardiomyocytes from hypoxia/reoxygenation-induced cell death and regulated mitochondrial bioenergetics in cardiomyocytes. Increased infarct size after ischemia/reperfusion injury in Aspn-/- mice confirmed Aspn's contribution to cardiomyocyte viability. Echocardiography revealed greater reduction in left ventricular systolic function post-I/R in the Aspn-/- animals compared to wild type. Furthermore, we developed an ASPN-mimic peptide using molecular modeling and docking which when administered to mice prevented TAC-induced fibrosis and preserved heart function. The peptide also reduced infarct size after I/R in mice, demonstrating the translational potential of ASPN-based therapy. Thus, we establish the role of ASPN as a critical ECM molecule that regulates cardiac remodeling to preserve heart function.

Proteomics of Mouse Heart Ventricles Reveals Mitochondria and Metabolism as Major Targets of a Post-Infarction Short-Acting GLP1Ra-Therapy.

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.

Elevated Asparagine Biosynthesis Drives Brain Tumor Stem Cell Metabolic Plasticity and Resistance to Oxidative Stress.

Asparagine synthetase (ASNS) is a gene on the long arm of chromosome 7 that is copy-number amplified in the majority of glioblastomas. ASNS copy-number amplification is associated with a significantly decreased survival. Using patient-derived glioma stem cells (GSC), we showed that significant metabolic alterations occur in gliomas when perturbing the expression of ASNS, which is not merely restricted to amino acid homeostasis. ASNS-high GSCs maintained a slower basal metabolic profile yet readily shifted to a greatly increased capacity for glycolysis and oxidative phosphorylation when needed. This led ASNS-high cells to a greater ability to proliferate and spread into brain tissue. Finally, we demonstrate that these changes confer resistance to cellular stress, notably oxidative stress, through adaptive redox homeostasis that led to radiotherapy resistance. Furthermore, ASNS overexpression led to modifications of the one-carbon metabolism to promote a more antioxidant tumor environment revealing a metabolic vulnerability that may be therapeutically exploited. IMPLICATIONS: This study reveals a new role for ASNS in metabolic control and redox homeostasis in glioma stem cells and proposes a new treatment strategy that attempts to exploit one vulnerable metabolic node within the larger multilayered tumor network.

Recruitment of pro-IL-1α to mitochondrial cardiolipin, via shared LC3 binding domain, inhibits mitophagy and drives maximal NLRP3 activation.

The balance between NLRP3 inflammasome activation and mitophagy is essential for homeostasis and cellular health, but this relationship remains poorly understood. Here we found that interleukin-1α (IL-1α)-deficient macrophages have reduced caspase-1 activity and diminished IL-1ß release, concurrent with reduced mitochondrial damage, suggesting a role for IL-1α in regulating this balance. LPS priming of macrophages induced pro-IL-1α translocation to mitochondria, where it directly interacted with mitochondrial cardiolipin (CL). Computational modeling revealed a likely CL binding motif in pro-IL-1α, similar to that found in LC3b. Thus, binding of pro-IL-1α to CL in activated macrophages may interrupt CL-LC3b-dependent mitophagy, leading to enhanced Nlrp3 inflammasome activation and more robust IL-1ß production. Mutation of pro-IL-1α residues predicted to be involved in CL binding resulted in reduced pro-IL-1α-CL interaction, a reduction in NLRP3 inflammasome activity, and increased mitophagy. These data identify a function for pro-IL-1α in regulating mitophagy and the potency of NLRP3 inflammasome activation.

Attenuation of Adverse Postinfarction Left Ventricular Remodeling with Empagliflozin Enhances Mitochondria-Linked Cellular Energetics and Mitochondrial Biogenesis.

Sodium-glucose cotransporter 2 (SGLT2) inhibitors such as empagliflozin are known to reduce the risk of hospitalizations related to heart failure irrespective of diabetic state. Meanwhile, adverse cardiac remodeling remains the leading cause of heart failure and death in the USA. Thus, understanding the mechanisms that are responsible for the beneficial effects of SGLT2 inhibitors is of the utmost relevance and importance. Our previous work illustrated a connection between adverse cardiac remodeling and the regulation of mitochondrial turnover and cellular energetics using a short-acting glucagon-like peptide-1 receptor agonist (GLP1Ra). Here, we sought to determine if the mechanism of the SGLT2 inhibitor empagliflozin (EMPA) in ameliorating adverse remodeling was similar and/or to identify what differences exist, if any. To this end, we administered permanent coronary artery ligation to induce adverse remodeling in wild-type and Parkin knockout mice and examined the progression of adverse cardiac remodeling with or without EMPA treatment over time. Like GLP1Ra, we found that EMPA affords a robust attenuation of PCAL-induced adverse remodeling. Interestingly, unlike the GLP1Ra, EMPA does not require Parkin to improve/maintain mitochondria-related cellular energetics and afford its benefits against developing adverse remodeling. These findings suggests that further investigation of EMPA is warranted as a potential path for developing therapy against adverse cardiac remodeling for patients that may have Parkin and/or mitophagy-related deficiencies.

One-Year Effects of Omega-3 Treatment on Fatty Acids, Oxylipins, and Related Bioactive Lipids and Their Associations with Clinical Lipid and Inflammatory Biomarkers: Findings from a Substudy of the Vitamin D and Omega-3 Trial (VITAL).

Omega-3 (n-3) treatment may lower cardiovascular risk, yet its effects on the circulating lipidome and relation to cardiovascular risk biomarkers are unclear. We hypothesized that n-3 treatment is associated with favorable changes in downstream fatty acids (FAs), oxylipins, bioactive lipids, clinical lipid and inflammatory biomarkers. We examined these VITAL200, a nested substudy of 200 subjects balanced on demographics and treatment and randomly selected from the Vitamin D and Omega-3 Trial (VITAL). VITAL is a randomized double-blind trial of 840 mg/d eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) vs. placebo among 25,871 individuals. Small polar bioactive lipid features, oxylipins and FAs from plasma and red blood cells were measured using three independent assaying techniques at baseline and one year. The Women's Health Study (WHS) was used for replication with dietary n-3 intake. Randomized n-3 treatment led to changes in 143 FAs, oxylipins and bioactive lipids (False Discovery Rate (FDR) < 0.05 in VITAL200, validated (p-values < 0.05)) in WHS with increases in 95 including EPA, DHA, n-3 docosapentaenoic acid (DPA-n3), and decreases in 48 including DPA-n6, dihomo gamma linolenic (DGLA), adrenic and arachidonic acids. N-3 related changes in the bioactive lipidome were heterogeneously associated with changes in clinical lipid and inflammatory biomarkers. N-3 treatment significantly modulates the bioactive lipidome, which may contribute to its clinical benefits.

Mitochondrial division inhibitor 1 (mdivi-1) increases oxidative capacity and contractile stress generated by engineered skeletal muscle.

In skeletal muscle fibers, mitochondria are densely packed adjacent to myofibrils because adenosine triphosphate (ATP) is needed to fuel sarcomere shortening. However, despite this close physical and biochemical relationship, the effects of mitochondrial dynamics on skeletal muscle contractility are poorly understood. In this study, we analyzed the effects of Mitochondrial Division Inhibitor 1 (mdivi-1), an inhibitor of mitochondrial fission, on the structure and function of both mitochondria and myofibrils in skeletal muscle tissues engineered on micromolded gelatin hydrogels. Treatment with mdivi-1 did not alter myotube morphology, but did increase the mitochondrial turbidity and oxidative capacity, consistent with reduced mitochondrial fission. Mdivi-1 also significantly increased basal, twitch, and tetanus stresses, as measured using the Muscular Thin Film (MTF) assay. Finally, mdivi-1 increased sarcomere length, potentially due to mdivi-1-induced changes in mitochondrial volume and compression of myofibrils. Together, these results suggest that mdivi-1 increases contractile stress generation, which may be caused by an increase in maximal respiration and/or sarcomere length due to increased volume of individual mitochondria. These data reinforce that mitochondria have both biochemical and biomechanical roles in skeletal muscle and that mitochondrial dynamics can be manipulated to alter muscle contractility.

Intermittent Use of a Short-Course Glucagon-like Peptide-1 Receptor Agonist Therapy Limits Adverse Cardiac Remodeling via Parkin-dependent Mitochondrial Turnover.

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.

Antiviral Effects of Menthol on Coxsackievirus B.

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.

MitoPlex: A targeted multiple reaction monitoring assay for quantification of a curated set of mitochondrial proteins.

Mitochondria are the major source of cellular energy (ATP), as well as critical mediators of widespread functions such as cellular redox balance, apoptosis, and metabolic flux. The organelles play an especially important role in the maintenance of cardiac homeostasis; their inability to generate ATP following impairment due to ischemic damage has been directly linked to organ failure. Methods to quantify mitochondrial content are limited to low throughput immunoassays, measurement of mitochondrial DNA, or relative quantification by untargeted mass spectrometry. Here, we present a high throughput, reproducible and quantitative mass spectrometry multiple reaction monitoring based assay of 37 proteins critical to central carbon chain metabolism and overall mitochondrial function termed 'MitoPlex'. We coupled this protein multiplex with a parallel analysis of the central carbon chain metabolites (219 metabolite assay) extracted in tandem from the same sample, be it cells or tissue. In tests of its biological applicability in cells and tissues, "MitoPlex plus metabolites" indicated profound effects of HMG-CoA Reductase inhibition (e.g., statin treatment) on mitochondria of i) differentiating C2C12 skeletal myoblasts, as well as a clear opposite trend of statins to promote mitochondrial protein expression and metabolism in heart and liver, while suppressing mitochondrial protein and ii) aspects of metabolism in the skeletal muscle obtained from C57Bl6 mice. Our results not only reveal new insights into the metabolic effect of statins in skeletal muscle, but present a new high throughput, reliable MS-based tool to study mitochondrial dynamics in both cell culture and in vivo models.

ß2 -adrenoceptor activation improves skeletal muscle autophagy in neurogenic myopathy.

ß2 -adrenoceptor agonists improve autophagy and re-establish proteostasis in cardiac cells; therefore, suggesting autophagy as a downstream effector of ß2 -adrenoceptor signaling pathway. Here, we used the pharmacological and genetic tools to determine the autophagy effect of sustained ß2 -adrenoceptor activation in rodents with neurogenic myopathy, which display impaired skeletal muscle autophagic flux. Sustained ß2 -adrenoceptor activation using Formoterol (10 µg kg-1  day-1 ), starting at the onset of neurogenic myopathy, prevents disruption of autophagic flux in skeletal muscle 14 days after sciatic nerve constriction. These changes are followed by reduction of the cytotoxic protein levels and increased skeletal muscle cross-sectional area and contractility properties. Of interest, sustained administration of Formoterol at lower concentration (1 µg kg-1  day-1 ) induces similar improvements in skeletal muscle autophagic flux and contractility properties in neurogenic myopathy, without affecting the cross-sectional area. Sustained pharmacological inhibition of autophagy using Chloroquine (50 mg kg-1  day-1 ) abolishes the beneficial effects of ß2 -adrenoceptor activation on the skeletal muscle proteostasis and contractility properties in neurogenic myopathy. Further supporting an autophagy mechanism for ß2 -adrenoceptor activation, skeletal muscle-specific deletion of ATG7 blunts the beneficial effects of ß2 -adrenoceptor on skeletal muscle proteostasis and contractility properties in neurogenic myopathy in mice. These findings suggest autophagy as a critical downstream effector of ß2 -adrenoceptor signaling pathway in skeletal muscle.

Simvastatin induces autophagic flux to restore cerulein-impaired phagosome-lysosome fusion in acute pancreatitis.

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.

Matrix-guided control of mitochondrial function in cardiac myocytes.

In ventricular myocardium, extracellular matrix (ECM) remodeling is a hallmark of physiological and pathological growth, coincident with metabolic rewiring of cardiac myocytes. However, the direct impact of the biochemical and mechanical properties of the ECM on the metabolic function of cardiac myocytes is mostly unknown. Furthermore, understanding the impact of distinct biomaterials on cardiac myocyte metabolism is critical for engineering physiologically-relevant models of healthy and diseased myocardium. For these reasons, we systematically measured morphological and metabolic responses of neonatal rat ventricular myocytes cultured on fibronectin- or gelatin-coated polydimethylsiloxane (PDMS) of three elastic moduli and gelatin hydrogels with four elastic moduli. On all substrates, total protein content, cell morphology, and the ratio of mitochondrial DNA to nuclear DNA were preserved. Cytotoxicity was low on all substrates, although slightly higher on PDMS compared to gelatin hydrogels. We also quantified oxygen consumption rates and extracellular acidification rates using a Seahorse extracellular flux analyzer. Our data indicate that several metrics associated with baseline glycolysis and baseline and maximum mitochondrial function are enhanced when cardiac myocytes are cultured on gelatin hydrogels compared to all PDMS substrates, irrespective of substrate rigidity. These results yield new insights into how mechanical and biochemical cues provided by the ECM impact mitochondrial function in cardiac myocytes. STATEMENT OF SIGNIFICANCE: Cardiac development and disease are associated with remodeling of the extracellular matrix coincident with metabolic rewiring of cardiac myocytes. However, little is known about the direct impact of the biochemical and mechanical properties of the extracellular matrix on the metabolic function of cardiac myocytes. In this study, oxygen consumption rates were measured in neonatal rat ventricular myocytes maintained on several commonly-used biomaterial substrates to reveal new relationships between the extracellular matrix and cardiac myocyte metabolism. Several mitochondrial parameters were enhanced on gelatin hydrogels compared to synthetic PDMS substrates. These data are important for comprehensively understanding matrix-regulation of cardiac myocyte physiology. Additionally, these data should be considered when selecting scaffolds for engineering in vitro cardiac tissue models.

Mitophagy protects against statin-mediated skeletal muscle toxicity.

The deleterious effects of statins on skeletal muscle are well known, but the mechanism associated with these effects remains unresolved. Statins are associated with mitochondrial damage, which may contribute to muscle myopathy. Here we demonstrate that simvastatin induces mitophagy in skeletal muscle cells and hypothesized that attenuating this process by silencing the mitophagy adapter p62/sequestosome-1 (SQSTM1) might mitigate myotoxicity. Surprisingly, silencing p62/SQSTM1 in differentiated C2C12 muscle cells exacerbated rather than attenuated myotoxicity. This inhibition of mitophagy in the face of statin challenge correlated with increased release of cytochrome c to the cytosol, activation of caspase-3, and lactate dehydrogenase (LDH) release. Correspondingly, targeted knockdown of Parkin, a canonical E3 ubiquitin ligase important for mitophagy, mirrored the effects of p62/SQSTM1 silencing. To corroborate these findings in vivo, we treated Parkin knockout mice with simvastatin for 2 wk. In line with our findings in vitro, these mitophagy-compromised mice displayed reduced spontaneous activity, loss of grip strength, and increased circulating levels of muscle damage marker LDH. Our findings demonstrate that mitophagy is an important mechanism to resist statin-induced skeletal muscle damage.-Ramesh, M., Campos, J. C., Lee, P., Song, Y., Hernandez, G., Sin, J., Tucker, K. C., Saadaeijahromi, H., Gurney, M., Ferreira, J. C. B., Andres, A. M. Mitophagy protects against statin-mediated skeletal muscle toxicity.

Myocardial hypothermia increases autophagic flux, mitochondrial mass and myocardial function after ischemia-reperfusion injury.

Animal studies have demonstrated beneficial effects of therapeutic hypothermia on myocardial function, yet exact mechanisms remain unclear. Impaired autophagy leads to heart failure and mitophagy is important for mitigating ischemia/reperfusion injury. This study aims to investigate whether the beneficial effects of therapeutic hypothermia are due to preserved autophagy and mitophagy. Under general anesthesia, the left anterior descending coronary artery of 19 female farm pigs was occluded for 90 minutes with consecutive reperfusion. 30 minutes after reperfusion, we performed pericardial irrigation with warm or cold saline for 60 minutes. Myocardial tissue analysis was performed one and four weeks after infarction. Therapeutic hypothermia induced a significant increase in autophagic flux, mitophagy, mitochondrial mass and function in the myocardium after infarction. Cell stress, apoptosis, inflammation as well as fibrosis were reduced, with significant preservation of systolic and diastolic function four weeks post infarction. We found similar biochemical changes in human samples undergoing open chest surgery under hypothermic conditions when compared to the warm. These results suggest that autophagic flux and mitophagy are important mechanisms implicated in cardiomyocyte recovery after myocardial infarction under hypothermic conditions. New therapeutic strategies targeting these pathways directly could lead to improvements in prevention of heart failure.

Coxsackievirus B infection induces the extracellular release of miR-590-5p, a proviral microRNA.

Coxsackievirus B is a significant human pathogen and is a leading cause of myocarditis. We and others have observed that certain enteroviruses including coxsackievirus B cause infected cells to shed extracellular vesicles containing infectious virus. Recent reports have shown that vesicle-bound virus can infect more efficiently than free virus. Though microRNAs are differentially regulated in cells following infection, few have been associated with the vesicles shed from infected cells. Here we report exclusive trafficking of specific microRNAs into viral vesicles compared to vesicles from non-infected cells. We found that the most highly-expressed unique microRNA in viral vesicles was miR-590-5p, which facilitates prolonged viral replication by blocking apoptotic factors. Cells over-expressing this miR were significantly more susceptible to infection. This may be a mechanism by which coxsackievirus B boosts subsequent rounds of infection by co-packaging virus and a select set of pro-viral microRNAs in extracellular vesicles.

Retraction Note: Endocrine disruptors induce perturbations in endoplasmic reticulum and mitochondria of human pluripotent stem cell derivatives.

This paper has been retracted at the request of the authors.

Decrease of Cardiac Parkin Protein in Obese Mice.

Mitophagy plays a major role in heart physiology. Impairment of Parkin-dependent mitophagy in heart is known to be deleterious. Obesity is a known cardiovascular risk factor. Impaired autophagy has been reported in models of obesity or hyperlipidemia/hypercholesterolemia; however less is known regarding obesity and mitophagy. The aim of this study was to evaluate the regulation of Parkin expression in hearts of mice fed a high fat diet. Interestingly, we found a significant decrease in Parkin protein in hearts of HFD mice compared those fed a low-fat diet. This was associated with mitochondrial dysfunction in the context of ischemia/reperfusion (I/R). This downregulation was not associated with a decrease in Parkin mRNA expression. We did not detect any change in the degradation rate of Parkin and only a slight decrease in its translation. The reduction of Parkin protein abundance in HFD hearts remains a mystery and will need further studies. However, Parkin depletion in the setting of obesity may contribute to cardiovascular risk.