MicroRNA-34c-5p provokes isoprenaline-induced cardiac hypertrophy by modulating autophagy via targeting ATG4B

Pathological cardiac hypertrophy serves as a significant foundation for cardiac dysfunction and heart failure. Recently, growing evidence has revealed that microRNAs (miRNAs) play multiple roles in biological processes and participate in cardiovascular diseases. In the present research, we investigate the impact of miRNA-34c-5p on cardiac hypertrophy and the mechanism involved. The expression of miR-34c-5p was proved to be elevated in heart tissues from isoprenaline (ISO)-infused mice. ISO also promoted miR-34c-5p level in primary cultures of neonatal rat cardiomyocytes (NRCMs). Transfection with miR-34c-5p mimic enhanced cell surface area and expression levels of foetal-type genes atrial natriuretic factor (Anf) and β-myosin heavy chain (β-Mhc) in NRCMs. In contrast, treatment with miR-34c-5p inhibitor attenuated ISO-induced hypertrophic responses. Enforced expression of miR-34c-5p by tail intravenous injection of its agomir led to cardiac dysfunction and hypertrophy in mice, whereas inhibiting miR-34c-5p by specific antagomir could protect the animals against ISO-triggered hypertrophic abnormalities. Mechanistically, miR-34c-5p suppressed autophagic flux in cardiomyocytes, which contributed to the development of hypertrophy. Furthermore, the autophagy-related gene 4B (ATG4B) was identified as a direct target of miR-34c-5p, and miR-34c-5p was certified to interact with 3′ untranslated region of Atg4b mRNA by dual-luciferase reporter assay. miR-34c-5p reduced the expression of ATG4B, thereby resulting in decreased autophagy activity and induction of hypertrophy. Inhibition of miR-34c-5p abolished the detrimental effects of ISO by restoring ATG4B and increasing autophagy. In conclusion, our findings illuminate that miR-34c-5p participates in ISO-induced cardiac hypertrophy, at least partly through suppressing ATG4B and autophagy. It suggests that regulation of miR-34c-5p may offer a new way for handling hypertrophy-related cardiac dysfunction.     

Trehalose promotes functional recovery of keratinocytes under oxidative stress and wound healing via ATG5/ATG7

Wounds are in a stressed state, which precludes healing. Trehalose is a stress metabolite that protects cells under stress. Here, we explored whether trehalose reduces stress-induced wound tissue damage. A stress model was prepared by exposing human keratinocytes to hydrogen peroxide (H₂O₂), followed by trehalose treatment. Trehalose effects on expression of the autophagy-related proteins ATG5 and ATG7 and cell proliferation and migration were evaluated. For in vivo verification, a wound model was established in Sprague–Dawley rats, to measure the effects of trehalose wound-healing rate and reactive oxygen species (ROS) content. Histological changes during wound healing and trehalose's effects on ATG5 and ATG7 expression, necrosis, and apoptosis were examined·H₂O₂ stress increased ATG5 and ATG7 expression in vitro, but this was insufficient to prevent stress-induced damage. Trehalose further increased ATG5/ATG7 levels, which restored proliferation and increased migration by depolymerizing the cytoskeleton. However, trehalose did not exert these effects after ATG5 and ATG7 knockout. In vivo, the ROS content was higher in the wound tissue than in normal skin. Trehalose increased ATG5/ATG7 expression in wound tissue keratinocytes, reduced necrosis, depolymerized the cytoskeleton, and promoted cell migration, thereby promoting wound healing.     

Hydrogen sulfide inhibits human T-cell leukemia virus type-1 (HTLV-1) protein expression via regulation of ATG4B

Hydrogen sulfide (H₂S) is a redox gasotransmitter. It has been shown that H₂S has a key role in host antiviral defense by inhibiting interleukin production and S-sulfhydrating Keap1 lead to Nrf2/ARE pathway activation. However, it is yet unclear whether H₂S can play an antiviral role by regulating autophagy. In this study, we found that exogenous H₂S decreased the expression of human T-cell leukemia virus type-1 (HTLV-1) protein and HTLV-1 induced autophagosomes accumulation. Transmission electron microscope assays indicated that autophagosomes accumulation decreased after H₂S administration. HTLV-1-transformed T-cell lines had a high level of CSE (H₂S endogenous enzyme) which could be induced in Hela by HTLV-1 infection. Immunoblot demonstrated that overexpression of CSE inhibited HTLV-1 protein expression and autophagy. And we got the opposite after CSE knockdown. Meanwhile, H₂S could not restrain the autophagy when ATG4B had a mutant at its site of 89. In a word, these results suggested that H₂S modulated HTLV-1 protein expression via ATG4B. Therefore, our findings suggested a new mechanism by which H₂S defended against virus infection.     

DNTT activation,TdT-aided gene length mutation,and better prognosis in ATG-based regimen allo-HSCT in AML

This study aimed to investigate the relationship between anomalous DNA nucleotidylexotransferase (DNTT) activation and the mutagenesis of gene length mutations (LMs) in acute myeloid leukemia (AML), and the relevance of their prognosis in antithymocyte globulin (ATG)-based regimen allogeneic hematopoietic stem cell transplantation (allo-HSCT). A cohort of 578 AML cases was enrolled. Next-generation sequencing was performed to screen mutations of 86 leukemia driver genes. RNA-seq was used to analyze gene expression. Prognostic analysis was investigated in 239 AML cases who underwent ATG-based regimen allo-HSCT. We report a refined subtyping algorithm of LMs (type I–IV) based on sequence anatomy considering the TdT-aided mutagenesis mechanism. GC content adjacent to LM junctions, inserted nontemplate nucleotide bases, and DNTT expression analysis supported the DNTT activation and TdT-aided mutagenesis in type II/III LMs in the total AML cohort. Both single-variate and multivariate analyses showed a better overall survival of FLT3 type III compared to type I in a subset of ATG-based regimen allo-HSCT cases. The novel LM subtyping algorithm not only deciphers the etiology of the mutagenesis of LMs but also helps to fine-tune prognosis differentiation in AML. The possible prognostic versatility of this novel LM subtyping algorithm in terms of chemotherapy, targeted therapy, and allo-HSCT merits further investigation.     

ATG16L1基因启动子单核苷酸多态性可增加急性心肌梗死的易感性

目的 探讨ATG16L1基因启动子序列单核苷酸多态性(SNP)与急性心肌梗死(AMI)的相关性。方法采用病例-对照研究方法,对285例AMI患者和296例对照人群的ATG16L1基因启动子采用聚合酶链反应扩增片段并测序,结合DNA测序后的序列及比对SNP数据库后进行数据统计和分析。运用Hardy-Weinberg平衡检验后,应用χ²检验和t检验进行相关分析。采用Logistic回归对多种危险因素以及3个SNP位点与AMI易感性进行关联性分析。用Haploview 4.2软件和SHEsis在线软件进行连锁不平衡及单倍型分析。TRANSFAC数据库用于预测可能受SNP影响的转录因子的结合位点。结果 多因素Logistic回归分析结果显示男性、吸烟史、高血压是AMI的独立危险因素(P＜0.05),而高密度脂蛋白胆固醇是AMI的保护因素(P＜0.05)。在ATG16L1基因启动子序列中的3个SNP(rs1816753、rs12476635、rs2289477)中,rs1816753的TC基因型与AMI间存在关联,可明显增加AMI的患病风险(OR=2.519,95%CI:1.130～5.615,P＝0.024)。通过Haploview 4.2软件分析显示3个SNP之间呈强连锁。结论 ATG16L1基因启动子SNP可能与AMI易感性相关,rs1816753的TC基因型可能是AMI的遗传危险因素。