Alleviation of doxorubicin-induced cardiomyocyte death through miR-147-y-mediated mitophagy.

Doxorubicin (DOX) is a commonly used antitumor drug. However, it may cause severe cardiotoxicity, apoptosis being a major change. A recent report indicates that miR-147 expression is decreased in the myocardium of a myocardial infarction model, suggesting a potential role of this miRNA in DOX-induced cardiomyocyte toxicity. In this study, freshly isolated neonatal pig cardiomyocytes were used; following transfection of a miR-147-y mimic, the cell death induced by DOX was alleviated, represented by augmented mitophagy [indicated by a decrease in P62, and increases in LC3, PINK1, parkin mRNA, LC3Ⅱ/Ⅰ, beclin-1, PINK1, and parkin including p-parkin (Ser65) protein expression], prohibited cell apoptosis as determined by TUNEL staining, and the suppression of caspase-3 transcription and cleaved caspase-3 translation. In cells transfected with an miR-147-y inhibitor, DOX-induced mitophagy was decreased, while apoptosis was increased. Additionally, RAPTOR gene silencing in cardiomyocytes exposed to DOX increased the rate of mitophagy and decreased that of apoptosis as compared with the treatment with DOX alone. Moreover, RAPTOR overexpression downregulated the rate of mitophagy and increased that of apoptosis in cells exposed to DOX. RAPTOR was confirmed as the target gene of miR-147-y based on the results of luciferase reporter gene assays and the opposite effects of the miR-147-y mimic and miR-147-y inhibitor on RAPTOR expression. In summary, our study suggests that miR-147-y mediates DOX-induced cardiomyocyte mitophagy while suppresses apoptosis by targeting RAPTOR, thus playing a protective role in DOX-induced cardiomyocyte damage.

Prognostic Value of Depressive Symptoms for Cardiovascular Events in Female Patients With Heart Failure With Reduced Ejection Fraction and Heart Failure With Preserved Ejection Fraction.

BACKGROUND: Among those with heart failure (HF), women are more likely to develop depression than men. Few studies have focused on the outcomes of female patients with HF with depressive symptoms. METHODS AND RESULTS: A total of 506 female patients with HF with preserved ejection fraction were included in this secondary analysis from the TOPCAT (Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist) cohort, and 439 female patients with HF with reduced ejection fraction were included from the HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training) cohort. Depressive symptoms were measured using the Patient Health Questionnaire-9 and Beck Depression Inventory-II. The depression class was categorized by severity, and the change in clinical depression class was defined as aggravated (1-grade increase) or improved (1-grade decrease). The prognostic value of depressive symptoms was determined by using multivariable Cox proportional hazards models. Female patients with improved depressive symptoms had worse depressive status at baseline and lower baseline Kansas City Cardiomyopathy Questionnaire scores. Depression class at the 12-month visit and depression class change were the dominant prognostic factors for cardiovascular death in female patients with HF with preserved ejection fraction (hazard ratio [HR], 1.43 [95% CI, 1.02-2.01], P=0.036; HR, 1.71 [95% CI, 1.14-2.55], P=0.009). Among the patients with HF with reduced ejection fraction, both the depression class at baseline and depression class change had significant prognostic effects on cardiovascular death (HR, 3.30 [95% CI, 1.70-6.39], P<0.001; HR, 2.21 [95% CI, 1.28-3.80], P=0.004). However, the prognostic value of depressive assessments for hospitalization in patients with HF is unclear. CONCLUSIONS: In female patients with HF with reduced ejection fraction, the depression class at baseline was most strongly associated with cardiovascular death, whereas in female patients with HF with preserved ejection fraction, the change in depression class exhibited a more significant prognostic trend.

Activation of Piezo1 promotes osteogenic differentiation of aortic valve interstitial cell through YAP-dependent glutaminolysis.

Hemodynamic overload and dysregulation of cellular metabolism are involved in development of calcific aortic valve disease (CAVD). However, how mechanical stress relates to metabolic changes in CAVD remains unclear. Here, we show that Piezo1, a mechanosensitive ion channel, regulated glutaminase 1 (GLS1)-mediated glutaminolysis to promote osteogenic differentiation of valve interstitial cells (VICs). In vivo, two models of aortic valve stenosis were constructed by ascending aortic constriction (AAC) and direct wire injury (DWI). Inhibition of Piezo1 and GLS1 in these models respectively mitigated aortic valve lesion. In vitro, Piezo1 activation induced by Yoda1 and oscillatory stress triggered osteogenic responses in VICs, which were prevented by Piezo1 inhibition or knockdown. Mechanistically, Piezo1 activation promoted calcium-dependent Yes-associated protein (YAP) activation. YAP modulated GLS1-mediated glutaminolysis, which enhanced osteogenic differentiation through histone acetylation of runt-related transcription factor 2 (RUNX2) promoters. Together, our work provided a cross-talk between mechanotransduction and metabolism in the context of CAVD.

Machine learning models in heart failure with mildly reduced ejection fraction patients.

Objective: Heart failure with mildly reduced ejection fraction (HFmrEF) has been recently recognized as a unique phenotype of heart failure (HF) in current practical guideline. However, risk stratification models for mortality and HF re-hospitalization are still lacking. This study aimed to develop and validate a novel machine learning (ML)-derived model to predict the risk of mortality and re-hospitalization for HFmrEF patients. Methods: We assessed the risks of mortality and HF re-hospitalization in HFmrEF (45-49%) patients enrolled in the TOPCAT trial. Eight ML-based models were constructed, including 72 candidate variables. The Harrell concordance index (C-index) and DeLong test were used to assess discrimination and the improvement in discrimination between models, respectively. Calibration of the HF risk prediction model was plotted to obtain bias-corrected estimates of predicted versus observed values. Results: Least absolute shrinkage and selection operator (LASSO) Cox regression was the best-performing model for 1- and 6-year mortality, with a highest C-indices at 0.83 (95% CI: 0.68-0.94) over a maximum of 6 years of follow-up and 0.77 (95% CI: 0.64-0.89) for the 1-year follow-up. The random forest (RF) showed the best discrimination for HF re-hospitalization, scoring 0.80 (95% CI: 0.66-0.94) and 0.85 (95% CI: 0.71-0.99) at the 6- and 1-year follow-ups, respectively. For risk assessment analysis, Kansas City Cardiomyopathy Questionnaire (KCCQ) subscale scores were the most important predictor of readmission outcome in the HFmrEF patients. Conclusion: ML-based models outperformed traditional models at predicting mortality and re-hospitalization in patients with HFmrEF. The results of the risk assessment showed that KCCQ score should be paid increasing attention to in the management of HFmrEF patients.

Hesperetin, a Promising Dietary Supplement for Preventing the Development of Calcific Aortic Valve Disease.

BACKGROUND: No effective therapeutic agents for calcific aortic valve disease (CAVD) are available currently. Dietary supplementation has been proposed as a novel treatment modality for various diseases. As a flavanone, hesperetin is widely abundant in citrus fruits and has been proven to exert protective effects in multiple diseases. However, the role of hesperetin in CAVD remains unclear. METHODS: Human aortic valve interstitial cells (VICs) were isolated from aortic valve leaflets. A mouse model of aortic valve stenosis was constructed by direct wire injury (DWI). Immunoblotting, immunofluorescence staining, and flow cytometry were used to investigate the roles of sirtuin 7 (Sirt7) and nuclear factor erythroid 2-related factor 2 (Nrf2) in hesperetin-mediated protective effects in VICs. RESULTS: Hesperetin supplementation protected the mice from wire-injury-induced aortic valve stenosis; in vitro, hesperetin inhibited the lipopolysaccharide (LPS)-induced activation of NF-κB inflammatory cytokine secretion and osteogenic factors expression, reduced ROS production and apoptosis, and abrogated LPS-mediated injury to the mitochondrial membrane potential and the decline in the antioxidant levels in VICs. These benefits of hesperetin may have been obtained by activating Nrf2-ARE signaling, which corrected the dysfunctional mitochondria. Furthermore, we found that hesperetin could directly bind to Sirt7 and that the silencing of Sirt7 decreased the effects of hesperetin in VICs and potently abolished the ability of hesperetin to increase Nrf2 transcriptional activation. CONCLUSIONS: Our work demonstrates that hesperetin plays protective roles in the aortic valve through the Sirt7-Nrf2-ARE axis; thus, hesperetin might be a potential dietary supplement that could prevent the development of CAVD.

Effects of Population Bottleneck and Balancing Selection on the Chinese Alligator Are Revealed by Locus-Specific Characterization of MHC Genes.

Chinese alligator (Alligator sinensis) is an endangered freshwater crocodilian endemic to China, which experienced a severe bottleneck about 30 years ago. In this study, we developed locus-specific primers to investigate the polymorphism of 3 major histocompatibility complex (MHC) loci in 3 Chinese alligator populations, in combination with 6 neutral microsatellite markers as a contrast. We found the genetic trace for the bottleneck effect on the endangered Chinese alligator: the low allelic diversity (2 alleles at each locus), the low nucleotide substitution rate (no more than 0.009) at all sites, the deviation from Hardy-Weinberg Equilibrium/heterozygote deficiency, and the significant Tajima's D values, indicating the MHC class I and class II loci being at different stages of bottleneck. We also obtained 3 pieces of evidence for balancing selection on this severely bottlenecked reptile: an obvious excess of nonsynonymous substitutions over synonymous at the antigen-binding positions, the mean synonymous substitution rate of MHC exons significantly higher than mean nucleotide substitution rate of introns, and the differentiation coefficient F ST of MHC loci significantly lower than that of microsatellite loci. Consequently, we emphasize that the Chinese alligator holds a pretty low adaptive ability and requires scientific conservation strategies to ensure the long-term population development.