LncRNA CHRF aggravates myocardial ischemia/reperfusion injury by enhancing autophagy via modulation of the miR-182-5p/ATG7 pathway

Oxidized DJ-1 activates the p-IKK/NF-κB/Beclin1 pathway by binding PTEN to induce autophagy and exacerbate myocardial ischemia-reperfusion injury

Patients with myocardial infarction have a much worse prognosis when they have myocardial ischemia-reperfusion (I/R) injury. Further research into the molecular basis of myocardial I/R injury is therefore urgently needed, as well as the identification of novel therapeutic targets and linkages to interventions. Three cysteine residues are present in DJ-1 at amino acids 46, 53, and 106 sites, with the cysteine at position 106 being the most oxidation-prone. This study sought to understand how oxidized DJ-1(C106) contributes to myocardial I/R damage. Rats' left anterior descending branches were tied off to establish a myocardial I/R model in vivo. A myocardial I/R model in vitro was established via anoxia/reoxygenation (A/R) of H9c2 cells. The results showed that autophagy increased after I/R, accompanied by the increased expression of oxidized DJ-1 (ox-DJ-1). In contrast, after pretreatment with NAC (N-acetylcysteine, a ROS scavenger) or Comp-23 (Compound-23, a specific antioxidant binding to the C106 site of DJ-1), the levels of ox-DJ-1, autophagy and LDH release decreased, and cell survival rate increased. Furthermore, the inhibition of interaction between ox-DJ-1 and PTEN could increase PTEN phosphatase activity, inhibit the p-IKK/NF-κB/Beclin1 pathway, reduce injurious autophagy, and alleviate A/R injury. However, BA (Betulinic acid, a NF-κB agonist) was able to reverse the protective effects produced by Comp-23 pretreatment. In conclusion, ox-DJ-1 could activate detrimental autophagy through the PTEN/p-IKK/NF-κB/Beclin1 pathway and exacerbate myocardial I/R injury.

Insights on E1-like enzyme ATG7: functional regulation and relationships with aging-related diseases

Autophagy is a dynamic self-renovation biological process that maintains cell homeostasis and is responsible for the quality control of proteins, organelles, and energy metabolism. The E1-like ubiquitin-activating enzyme autophagy-related gene 7 (ATG7) is a critical factor that initiates classic autophagy reactions by promoting the formation and extension of autophagosome membranes. Recent studies have identified the key functions of ATG7 in regulating the cell cycle, apoptosis, and metabolism associated with the occurrence and development of multiple diseases. This review summarizes how ATG7 is precisely programmed by genetic, transcriptional, and epigenetic modifications in cells and the relationship between ATG7 and aging-related diseases.

Mechanisms by which silencing long-stranded noncoding RNA KCNQ1OT1 alleviates myocardial ischemia/reperfusion injury (MI/RI)-induced cardiac injury via miR-377-3p/HMOX1

BACKGROUND

The key complication of myocardial infarction therapy is myocardial ischemia/reperfusion injury (MI/RI), and there is no effective treatment. The present study elucidates the mechanism of action of lncRNA KCNQ1OT1 in alleviating MI/RI and provides new perspectives and therapeutic targets for cardiac injury-related diseases.

METHODS

An ischemia/reperfusion (I/R) injury model of human adult cardiac myocytes (HACMs) was constructed, and the expression of KCNQ1OT1 and miR-377-3p was determined by RT‒qPCR. The levels of related proteins were detected by western blot analysis. Cell proliferation was detected by a CCK-8 assay, and cell apoptosis and ROS content were determined by flow cytometry. SOD and MDA expression as well as Fe2+ changes were detected by related analysis kits. The target binding relationships between lncRNA KCNQ1OT1 and miR-377-3p as well as between miR-377-3p and heme oxygenase 1 (HMOX1) were verified by a dual-luciferase reporter gene assay.

RESULTS

Myocardial ischemia‒reperfusion caused oxidative stress in HACMs, resulting in elevated ROS levels, increased Fe2+ levels, decreased cell viability, and increased LDH release (a marker of myocardial injury), and apoptosis. KCNQ1OT1 and HMOX1 were upregulated in I/R-induced myocardial injury, but the level of miR-377-3p was decreased. A dual-luciferase reporter gene assay indicated that lncRNA KCNQ1OT1 targets miR-377-3p and that miR-377-3p targets HMOX1. Inhibition of HMOX1 alleviated miR-377-3p downregulation-induced myocardial injury. Furthermore, lncRNA KCNQ1OT1 promoted the level of HMOX1 by binding to miR-377-3p and aggravated myocardial injury.

CONCLUSION

LncRNA KCNQ1OT1 aggravates ischemia‒reperfusion-induced cardiac injury via miR-377-3P/HMOX1.

The role and medical prospects of long non-coding RNAs in cardiovascular disease

Cardiovascular disease (CVD) has reached epidemic proportions and is a leading cause of death worldwide. One of the long-standing goals of scientists is to repair heart tissue damaged by various forms of CVD such as cardiac hypertrophy, dilated cardiomyopathy, myocardial infarction, heart fibrosis, and genetic and developmental heart defects such as heart valve deformities. Damaged or defective heart tissue has limited regenerative capacity and results in a loss of functioning myocardium. Advances in transcriptomic profiling technology have revealed that long noncoding RNA (lncRNA) is transcribed from what was once considered "junk DNA." It has since been discovered that lncRNAs play a critical role in the pathogenesis of various CVDs and in myocardial regeneration. This review will explore how lncRNAs impact various forms of CVD as well as those involved in cardiomyocyte regeneration. Further, we discuss the potential of lncRNAs as a therapeutic modality for treating CVD.

Knockdown of lncRNA SNHG16 attenuates myocardial ischemia‑reoxygenation injury via targeting miR‑183/FOXO1 axis

Accumulating evidence shows that long non-coding RNAs (lncRNAs) are widely involved in cellular processes of myocardial ischemia/reperfusion (I/R). The present study investigated the functions of lncRNA SNHG16 in myocardial I/R and the mechanism mediated by SNHG16. The myocardial I/R rat and cell model and hypoxia/reoxygenation injury (H/R) models of H9C2 cardiomyocytes were established to detect the expression of SNHG16. Cell Counting Kit-8, flow cytometric and western blot assays were conducted to detect cell viability, apoptosis and protein expression. Myocardial cell apoptosis was assessed by TUNEL staining. Dual-luciferase gene reporter was applied to determine the interaction between the molecules. The expressions of SNHG16 were upregulated in myocardial I/R injury models. Inhibition of SNHG16 relieved myocardial I/R injury in vivo and in vitro silencing of SNHG16 alleviated H/R induced cardiomyocyte apoptosis. To explore the regulatory mechanism, it was discovered that SNHG16 directly interacted with miR-183, while forkhead box O1 (FoxO1) was a target of microRNA (miR)-183. Findings from rescue assays revealed that miR-183 inhibitor and upregulation of FOXO1 can rescue the effect of sh-SNHG16 on H/R-induced cardiomyocyte apoptosis. The results indicated that the lncRNA SNHG16/miR-183/FOXO1 axis exacerbated myocardial cell apoptosis in myocardial I/R injury, suggesting SNHG16 as a potential therapeutic target for myocardial I/R injury.

Dexmedetomidine promotes cell proliferation and inhibits cell apoptosis by regulating LINC00982 and activating the phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT) signaling in hypoxia/reoxygenation-induced H9c2 cells

Previous studies showed dexmedetomidine (DEX) could alleviate myocardial ischemia/reperfusion injury (MIRI). Nevertheless, the mechanisms by which DEX alleviated MIRI remain to be determined. Our results demonstrated that DEX reversed hypoxia/reoxygenation (H/R)-induced decreased proliferation, and enhanced LINC00982 level, apoptosis, and inflammation in H9c2 cells. Moreover, LINC00982 overexpression attenuated the DEX-mediated protective effect of H9c2 cells under H/R. In addition, DEX upregulated p-phosphoinositide-3-kinase (p-PI3K) and p-protein kinase B (p-AKT) levels, and the silencing of LINC00982 further enhanced this effect in H/R-induced H9c2 cells. Furthermore, LINC00982 deletion enhanced the protective effect of DEX on H9c2 cells under H/R condition, while PI3K inhibitor, LY294002, obviously reversed this phenomenon. In sum, our work determined that DEX could suppress cell apoptosis and inflammation in H/R-triggered H9c2 through downregulating LINC00982 and activating PI3K/AKT signaling.