Regulation of autophagy of the heart in ischemia and reperfusion

Platelet-rich plasma combined with isometric quadriceps contraction regulates autophagy in chondrocytes via the PI3K/AKT/mTOR pathway to promote cartilage repair in knee osteoarthritis

Background

This study investigated the molecular mechanism by which the combination of platelet-rich plasma (PRP) and isometric contraction of the quadriceps (ICQ) intervention regulates autophagy in chondrocytes to prevent and treat knee osteoarthritis (KOA).

Methods

Thirty Sprague-Dawley rats were divided into a control group (CG, n = 6) and a model group (n = 24). After one week, the model group was randomly divided into a joint intervention group (JIG), a rapamycin group (RAG), an MHY1485 group (MYG), and a model blank group (MBG), with JIG, RAG, and MYG receiving the same combined intervention.

Results

The trend of cartilage lesions in each group was CG < RAG < JIG < MYG < MBG. Compared with MBG and MYG, JIG and RAG showed downregulation of IL-1β, IL-6, IL-18, MMP-13, and TNF-α mRNA in the cartilage (p < 0.01); mTOR protein expression: compared with JIG, RAG showed downregulation, and MYG showed upregulation. Compared with RAG, MYG showed upregulation (p < 0.01); ATG5 protein expression: compared with RAG, MYG showed downregulation (p < 0.01); Beclin1, LC3-I, and ULK1 protein expression: compared with JIG, RAG showed upregulation, and MYG showed downregulation (p < 0.01). Compared with RAG, MYG showed downregulation (p < 0.01); P62 protein expression: compared with RAG, both MBG and RAG showed upregulation, and MYG showed downregulation (p < 0.05); LC3-II/LC3-I ratio: compared with JIG and RAG, the ratio in MYG was decreased (p < 0.01).

Conclusion

The combined intervention promotes autophagy in chondrocytes by inhibiting the PI3K/AKT/mTOR pathway, downregulating inflammatory factors and MMP-13 in the cartilage, upregulating autophagy markers, inhibiting matrix degradation, and promoting cartilage repair.

Nek6 regulates autophagy through the mTOR signaling pathway to alleviate cerebral ischemia-reperfusion injury

OBJECTIVE

Cerebral ischemia-reperfusion injury (CIRI) is a major obstacle to neurological recovery after clinical treatment of ischemic stroke. The aim of this study was to investigate the molecular mechanism of Nek6 alleviating CIRI through autophagy after cerebral ischemia.

MATERIALS AND METHODS

A mouse model of CIRI was constructed by middle cerebral artery occlusion (MCAO). TUNEL staining was used to observe the apoptosis of neuronal cells. The oxygen glucose deprivation/reoxygenation (OGD/R) model was established by hypoxia and reoxygenation. The cell apoptosis and activity was detected. Western blot was performed to detect the expression of autophagy-related proteins, protein kinase B (Akt)/mammalian target of rapamycin (mTOR) and adenosine 5'-monophosphate-activated protein kinase (AMPK)/mTOR signaling pathway-related proteins. Cellular autophagy flux was observed by fluorometric method. NIMA-related kinase 6 (Nek6) mRNA stability was detected by actinomycin D treatment. Methylation RNA immunoprecipitation technique was used to detect Nek6 methylation level.

RESULTS

Nek6 expression was increased in both MCAO and OGD/R models. Overexpression of Nek6 in OGD/R inhibited apoptosis, decreased LC3II and Beclin-1 expression, increased p62 expression, and occurred lysosome dysfunction. Interference with Nek6 has opposite results. Nek6 overexpression promoted p-Akt and p-mTOR protein expressions, inhibited p-AMPK and p-UNC-51-like kinase 1 protein expressions and cell apoptosis, while LY294002, Rapamycin or RSVA405 treatment reversed this effect. Abnormal methyltransferase·like protein 3 (METTL3) expression in CIRI enhanced m6A modification and promoted Nek6 expression level.

CONCLUSION

This study confirmed that Nek6 regulates autophagy and alleviates CIRI through the mTOR signaling pathway, which provides a novel therapeutic strategy for patients with ischemic stroke in the future.

Deptor protects against myocardial ischemia-reperfusion injury by regulating the mTOR signaling and autophagy

Deptor knockout mice were constructed by crossing Deptor Floxp3 mice with myh6 Cre mice, establishing a myocardial ischemia-reperfusion (I/R) model. Deptor knockout mice exhibited significantly increased myocardial infarction size and increased myocardial apoptosis in vivo. ELISA analysis indicated that the expression of CK-MB, LDH, and CtnT/I was significantly higher in the Deptor knockout mice. Deptor siRNA significantly reduced cell activity and increased myocardial apoptosis after I/R-induced in vitro. Deptor siRNA also significantly up-regulated the expression of p-mTOR, p-4EBP1, and p62, and down-regulated the expression of LC3 after I/R induction. Immunofluorescence indicated that LC3 dual fluorescence was weakened by Deptor knockout, and was enhanced after transfection with Deptor-overexpression plasmids. Treatment with OSI027, a co-inhibitor of mTORC1 and mTORC2, in either Deptor knockout mice or Deptor knockout H9C2 cells, resulted in a significant reduction in infarction size and apoptotic cardiomyocytes. ELISA analysis also showed that the expression of CK-MB, LDH, and CtnT/I were significantly down-regulated by treatment with OSI027. CCK-8 cell viability indicated that cell viability was enhanced, and the number of apoptotic cells was decreased in vitro following treatment with OSI027. These results revealed that OSI027 exerts a protective effect on myocardial ischemia/reperfusion injury in both an in vivo and in an in vitro model of I/R. These findings demonstrate that Deptor protects against I/R-induced myocardial injury by inhibiting the mTOR pathway and by increasing autophagy.

Polysaccharides targeting autophagy to alleviate metabolic syndrome

Metabolic syndrome is a prevalent non-communicable disease characterized by central obesity, insulin resistance, hypertension, hyperglycemia, and hyperlipidemia. Epidemiological statistics indicate that one-third of the world's population is affected by metabolic syndrome. Unfortunately, owing to complicated pathogenesis and limited pharmacological options, the growing prevalence of metabolic syndrome threatens human health worldwide. Autophagy is an intracellular degradation mechanism that involves the degradation of unfolded or aggregated proteins and damaged cellular organelles, thereby maintaining metabolic homeostasis. Increasing evidence indicates that dysfunctional autophagy is closely associated with the development of metabolic syndrome, making it an attractive therapeutic target. Furthermore, a growing number of plant-derived polysaccharides have been shown to regulate autophagy, thereby alleviating metabolic syndrome, such as Astragalus polysaccharides, Laminaria japonica polysaccharides, Ganoderma lucidum polysaccharides and Lycium barbarum polysaccharides. In this review, we summarize recent advances in the discovery of autophagy modulators of plant polysaccharides for the treatment of metabolic syndrome, with the aim of providing precursor compounds for the development of new therapeutic agents. Additionally, we look forward to seeing more diseases being treated with plant polysaccharides by regulating autophagy, as well as the discovery of more intricate mechanisms that govern autophagy.

Fuzi polysaccharide isolated from Aconitum carmichaeli protects against liquid nitrogen cryopreservation-induced damage in rat abdominal aorta by enhancing autophagy

OBJECTIVE

To investigate the potential protective mechanisms of aconite polysaccharide (FZPS-1) during cryopreservation, with a particular emphasis on morphological changes in autophagy in rat abdominal aorta.

METHODS

Thirty-six male SD rats were divided into the control group, the cryopreserved model group, and the FZPS-1 intervention group treated with different concentrations of FZPS-1. The structural changes of the abdominal aortic wall were assessed via Masson staining, while cytolysosomes were identified using transmission electron microscopy (TEM). The expression of Beclin-1, LC3-II, and P62 was detected by immunohistochemistry (IHC) and western blot separately. Bcl-2 and Bax mRNA expression was measured by RT-qPCR.

RESULTS

Compared with the control group, the abdominal aortic wall in the model group was severely damaged. Contrarily, FZPS-1 10 mg/mL and 20 mg/mL groups had relatively normal structure of the blood vessel wall, higher cytolysosome counts, and increased Beclin-1 and LC3-II expression compared with the model group (all P<0.05); P62 expression also increased in the FZPS-1 20 mg/mL group (P<0.05). Compared with the control group, the mRNA expression of Bcl-2 in the cryopreservation model group was reduced (P<0.05), while Bax was increased (P<0.05). Compared with the cryopreservation model group, the mRNA expression of Bcl-2 was upregulated, while Bax was downregulated in the FPS 10 mg/L group (P<0.05).

CONCLUSION

During liquid nitrogen cryopreservation, autophagy is inhibited in the rat abdominal aorta, and the blood vessel wall structure is damaged. FZPS-1, as a cryoprotectant, can enhance autophagy and mitigate blood vessel wall damage in the rat abdominal aorta.

9-PAHSA ameliorates microvascular damage during cardiac ischaemia/reperfusion injury by promoting LKB1/AMPK/ULK1-mediated autophagy-dependent STING degradation

BACKGROUND

Considering that cardiac microvascular injury may play a more critical role than cardiomyocyte injury in the pathology of early ischaemia/reperfusion (I/R) injury, therapeutic strategies targeting the microvasculature are highly desirable. Palmitic acid-9-hydroxystearic acid (9-PAHSA) is a new class of bioactive anti-inflammatory lipids widely distributed in vegetables, fruits and medicinal plants, especially broccoli and apple. However, the pharmacological effects and underlying mechanisms of 9-PAHSA in protecting- against cardiac microvascular I/R injury have rarely been studied.

PURPOSE

This study aimed to explore the potential effects and molecular mechanisms of 9-PAHSA on the coronary microvasculature after cardiac I/R injury.

METHODS

Immunofluorescence staining, western blotting, and other experimental methods were used to evaluate the role and mechanism of 9-PAHSA in cardiac microvascular I/R injury in vivo and in vitro.

RESULTS

9-PAHSA administration significantly attenuated myocardial I/R-induced microvascular damage, as indicated by an impaired microvascular structure, reduced regional blood perfusion and decreased endothelial barrier function. In addition, 9-PAHSA administration protected the structure and function of coronary artery endothelial cells (CMECs) to resist I/R damage, an effect that was at least partially mediated by increased autophagy. Mechanistically, 9-PAHSA activated autophagy through the LKB1/AMPK/ULK1 pathway and promoted STING degradation via the autophagic‒lysosomal pathway.

CONCLUSIONS

To our best knowledge, this study is the first to report that 9-PAHSA attenuates cardiac microvascular I/R injury, potentially by activating LKB1/AMPK/ULK1-mediated autophagy-dependent STING degradation to suppress apoptosis. Thus, 9-PAHSA may be a promising therapeutic option for alleviating cardiac microvascular I/R injury.

LDHA exacerbates myocardial ischemia-reperfusion injury through inducing NLRP3 lactylation

Myocardial ischemia-reperfusion (I/R) injury caused by revascularization treatment is the leading cause of cardiac damage aggravation in ischemic heart disease. Increasing evidence has unraveled the crucial role of pyroptosis in myocardial I/R injury. Of note, lactylation has been validated to be participated in modulating pyroptosis. Hence, this study was aimed to elaborate the potential and mechanism of lactylation in myocardial I/R damage. We established the cell model of I/R through inducing hypoxia/reoxygenation (H/R) of H9c2 cells. It was uncovered that H/R stimulation drove cardiomyocyte pyroptosis and upregulated total lactylation level. Further, we demonstrated that promoting lactylation contributed to H/R-evoked pyroptosis, whereas silencing LDHA led to the opposite results. More than that, LDHA was confirmed to facilitate lactylation of NLRP3 at K245 site and increase its protein stability. Our findings indicated that activation of NLRP3 abolished the function of LDHA deficiency in H/R-treated H9c2 cells. In concert with the aforementioned outcomes, knockout of LDHA attenuated the infarct size and myocardial damage in I/R mice and upregulation of NLRP3 counteracted the effects of LDHA knockout on I/R-evoked injury in vivo. To summarize, the current research provided persuasive evidence that LDHA promoted myocardial I/R damage via enhancing NLRP3 lactylation to induce cardiomyocyte pyroptosis.

Apigenin inhibits proliferation and differentiation of cardiac fibroblasts through AKT/GSK3β signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Salvia miltiorrhiza Bunge (S. miltiorrhiza) is an important Traditional Chinese herbal Medicine (TCM) used to treat cardio-cerebrovascular diseases. Based on the pharmacodynamic substance of S. miltiorrhiza, the aim of present study was to investigate the underlying mechanism of S. miltiorrhiza against cardiac fibrosis (CF) through a systematic network pharmacology approach, molecular docking and dynamics simulation as well as experimental investigation in vitro.

MATERIALS AND METHODS

A systematic pharmacological analysis was conducted using the Traditional Chinese Medicine Pharmacology (TCMSP) database to screen the effective chemical components of S. miltiorrhiza, then the corresponding potential target genes of the compounds were obtained by the Swiss Target Prediction and TCMSP databases. Meanwhile, GeneCards, DisGeNET, OMIM, and TTD disease databases were used to screen CF targets, and a protein-protein interaction (PPI) network of drug-disease targets was constructed on S. miltiorrhiza/CF targets by Search Tool for the Retrieval of Interacting Genes/Proteins (STING) database. After that, the component-disease-target network was constructed by software Cytoscape 3.7. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were performed for the intersection targets between drug and disease. The relationship between active ingredient of S. miltiorrhiza and disease targets of CF was assessed via molecular docking and molecular dynamics simulation. Subsequently, the underlying mechanism of the hub compound on CF was experimentally investigated in vitro.

RESULTS

206 corresponding targets to effective chemical components from S. miltiorrhiza were determined, and among them, there were 82 targets that overlapped with targets of CF. Further, through PPI analysis, AKT1 and GSK3β were the hub targets, and which were both enriched in the PI3K/AKT signaling pathway, it was the sub-pathways of the lipid and atherosclerosis pathway. Subsequently, compound-disease-genes-pathways diagram is constructed, apigenin (APi) was a top ingredients and AKT1 (51) and GSK3β (22) were the hub genes according to the degree value. The results of molecular docking and dynamics simulation showed that APi has strong affinities with AKT and GSK3β. The results of cell experiments showed that APi inhibited cells viability, proliferation, proteins expression of α-SMA and collagen I/III, phosphorylation of AKT1 and GSK3β in MCFs induced by TGFβ1.

CONCLUSION

Through a systematic network pharmacology approach, molecular docking and dynamics simulation, and confirmed by in vitro cell experiments, these results indicated that APi interacts with AKT and GSK3β to disrupt the phosphorylation of AKT and GSK3β, thereby inhibiting the proliferation and differentiation of MCFs induced by TGFβ1, which providing new insights into the pharmacological mechanism of S. miltiorrhiza in the treatment of CF.

Hydrogen sulfide plays an important role by regulating microRNA in different ischemia-reperfusion injury

MicroRNAs (miRNAs) are the short endogenous non-coding RNAs that regulate the expression of the target gene at posttranscriptional level through degrading or inhibiting the specific target messenger RNAs (mRNAs). MiRNAs regulate the expression of approximately one-third of protein coding genes, and in most cases inhibit gene expression. MiRNAs have been reported to regulate various biological processes, such as cell proliferation, apoptosis and differentiation. Therefore, miRNAs participate in multiple diseases, including ischemia-reperfusion (I/R) injury. Hydrogen sulfide (H2S) was once considered as a colorless, toxic and harmful gas with foul smelling. However, in recent years, it has been discovered that it is the third gas signaling molecule after carbon monoxide (CO) and nitric oxide (NO), with multiple important biological functions. Increasing evidence indicates that H2S plays a vital role in I/R injury through regulating miRNA, however, the mechanism has not been fully understood. In this review, we summarized the current knowledge about the role of H2S in I/R injury by regulating miRNAs, and analyzed its mechanism in detail.

Protective effects of tetramethylpyrazine on myocardial ischemia/reperfusion injury involve NLRP3 inflammasome suppression by autophagy activation

Tetramethylpyrazine (TMP) belongs to the active ingredients of the traditional Chinese medicine Chuanxiong, which has a certain protective effect in myocardial ischemia-reperfusion (I/R) injury. It can improve postoperative cardiac function and alleviate ventricular remodeling in acute myocardial infarction patients. However, its specific protective mechanism is still unclear. In this study, a certain concentration of TMP was introduced into I/R mice or H9C2 cells after oxygen-glucose deprivation/reoxygenation (OGD/R) treatment to observe the effects of TMP on cardiomyocyte activity, cytotoxicity, apoptosis, autophagy, pyroptosis, and NLRP3 inflammasome activation. The results displayed that TMP intervention could reduce OGD/R and I/R-induced cardiomyocyte apoptosis, accelerate cellular activity and autophagy levels, and ameliorate myocardial tissue necrosis in I/R mice in a dose-dependent manner. Further, TMP prevented the formation of NLRP3 inflammasomes to suppress pyroptosis by increasing the level of cardiomyocyte autophagy after I/R and OGD/R modelling, the introduction of chloroquine to suppress autophagic activity in vivo and in vitro was further analyzed to confirm whether TMP inhibits NLRP3 inflammasome activation and pyroptosis by increasing autophagy, and we found the inhibitory effect of TMP on NLRP3 inflammasomes and its protective effect against myocardial injury were blocked when autophagy was inhibited with chloroquine. In conclusion, this experiment demonstrated that TMP unusually attenuated I/R injury in mice, and this protective effect was achieved by inhibiting the activation of NLRP3 inflammasomes through enhancing autophagic activity.

Quercetin activates autophagy in the distal ischemic area of random skin flaps through Beclin1 to enhance the adaptability to energy deficiency

Random flaps are frequently employed in treating substantial skin abnormalities and in surgical tissue-rebuilding interventions. The random flap technique provides flaps of specific dimensions and contours to fit the surgical incision. However, blood supply deficiency and subsequent ischemia-reperfusion injury can cause severe oxidative stress and apoptosis, eventually leading to distal necrosis, which limits the clinical application of the flap. Quercetin (QUE) is primarily found in the glycoside form in many plant parts, such as stem bark, flowers, leaves, buds, seeds, and fruits. Cellular, animal, and clinical studies have demonstrated the antioxidant, anti-apoptosis, anti-inflammatory, and activation of autophagy properties of QUE. In previous studies, high doses of QUE effectively suppressed the survival of human umbilical vein endothelial cells (HUVECs) stimulated by hydrogen peroxide. However, different concentration gradients of QUE on HUVECs revealed a significant protective effect at a concentration of 10 mM. The protective impact of QUE on HUVECs was evaluated using scratch tests, CCK-8 assays, and EDU assays. Simultaneously, a mouse model of random skin flap was created, and the impact of QUE on skin flap survival was examined by intragastric injection. The QUE group showed a significantly larger survival area of the random flap and higher blood flow intensity compared to the control group. Furthermore, the beneficial effects of QUE were reversed by the autophagy inhibitor 3-MA. Therefore, autophagy plays a significant role in the therapeutic benefits of QUE on flap survival.

Myocardial ischemia-reperfusion injury upregulates nucleostemin expression via HIF-1α and c-Jun pathways and alleviates apoptosis by promoting autophagy

Myocardial ischemia-reperfusion (I/R) injury, often arising from interventional therapy for acute myocardial infarction, leads to irreversible myocardial cell death. While previous studies indicate that nucleostemin (NS) is induced by myocardial I/R injury and mitigates myocardial cell apoptosis, the underlying mechanisms are poorly understood. Here, our study reveals that NS upregulation is critical for preventing cardiomyocyte death following myocardial I/R injury. Elevated NS protein levels were observed in myocardial I/R injury mouse and rat models, as well as Hypoxia/reoxygenation (H/R) cardiac cell lines (H9C2 cells). We identified binding sites for c-Jun and HIF-1α in the NS promoter region. Inhibition of JNK and HIF-1α led to a significant decrease in NS transcription and protein expression. Furthermore, inhibition of autophagy and NS expression promoted myocardial cell apoptosis in H/R. Notably, the cell model showed reduced LC3I transformation to LC3II, downregulated Beclin1, upregulated p62, and altered expression of autophagy-related proteins upon NS interference in H/R cells. These findings suggest that NS expression, driven by c-Jun and HIF-1α pathways, facilitates autophagy, providing protection against both myocardial I/R injury and H/R-induced cardiomyocyte apoptosis.

Inhibiting SNX10 induces autophagy to suppress invasion and EMT and inhibits the PI3K/AKT pathway in cervical cancer

PURPOSE

Cervical cancer (CC) is a prevalent malignancy among women with high morbidity and poor prognosis. Sorting nexin 10 (SNX10) is a newly recognized cancer regulatory factor, while its action on CC progression remains elusive. Hence, this study studied the effect of SNX10 on CC development and investigated the mechanism.

METHODS

The SNX10 level in CC and the overall survival of CC cases with different SNX10 expressions were determined by bioinformatics analysis in GEPIA. The SNX10 expression in tumor tissues and clinical significance were studied in 64 CC cases. The overall survival was assessed using Kaplan-Meier analysis. The formation of LC3 was evaluated using immunofluorescence. Cell invasion was measured using the Transwell assay. Epithelial-to-mesenchymal transition (EMT) was determined by observing cell morphology and assessing EMT marker levels. A xenograft tumor was constructed to evaluate tumor growth.

RESULTS

SNX10 was elevated in CC tissues and cells, and the CC cases with high SNX10 levels exhibited poor overall survival. Besides, SNX10 correlated with the FIGO stage, lymph node invasion, and stromal invasion of CC. SNX10 silencing induced CC cell autophagy and suppressed CC cell invasion and EMT. Meanwhile, silenced SNX10 could suppress invasion and EMT via inducing autophagy. Furthermore, SNX10 inhibition suppressed the PI3K/AKT pathway. Moreover, silenced SNX10 restrained the tumor growth, autophagy, and EMT of CC in vivo.

CONCLUSION

SNX10 was enhanced in CC and correlated with poor prognosis. Silenced SNX10 induced autophagy to suppress invasion and EMT and inhibited the PI3K/AKT pathway in CC, making SNX10 a valuable molecule for CC therapy.

DJ-1: Potential target for treatment of myocardial ischemia-reperfusion injury

Ischemic heart disease (IHD) is a significant global health concern, resulting in high rates of mortality and disability among patients. Although coronary blood flow reperfusion is a key treatment for IHD, it often leads to acute myocardial ischemia-reperfusion injury (IRI). Current intervention strategies have limitations in providing adequate protection for the ischemic myocardium. DJ-1, originally known as a Parkinson's disease related protein, is a highly conserved cytoprotective protein. It is involved in enhancing mitochondrial function, scavenging reactive oxygen species (ROS), regulating autophagy, inhibiting apoptosis, modulating anaerobic metabolism, and exerting anti-inflammatory effects. DJ-1 is also required for protective strategies, such as ischemic preconditioning, ischemic postconditioning, remote ischemic preconditioning and pharmacological conditioning. Therefore, DJ-1 emerges as a potential target for the treatment of myocardial IRI. Our comprehensive review delves into its protective mechanisms in myocardial IRI and the structural foundations underlying its functions.

Bibliometric analysis of skeletal muscle ischemia/reperfusion (I/R) research from 1986 to 2022

Introduction

Tissue damage due to ischemia and reperfusion is a critical medical problem worldwide. Studies in this field have made remarkable advances in understanding the pathogenesis of ischemia/reperfusion (I/R) injury and its treatment with new and known drugs. However, no bibliometric analysis exists in this area of research.

Methods

Research articles and reviews related to skeletal muscle I/R from 1986 to 2022 were retrieved from the Web of Science Core Collection. Bibliometric analysis was performed using Microsoft Excel 2019, VOSviewer (version 1.6.19), Bibliometrix (R-Tool for R-Studio), and CiteSpace (version 6.1.R5).

Results

A total of 3682 research articles and reviews from 2846 institutions in 83 countries were considered in this study. Most studies were conducted in the USA. Hobson RW (UMDNJ-New Jersey Medical School) had the highest publication, and Korthuis RJ (Louisiana State University) had the highest co-citations. Our analysis showed that, though the Journal of Surgical Research was most favored, the Journal of Biological Chemistry had the highest number of co-citations. The pathophysiology, interventions, and molecular mechanisms of skeletal muscle I/R injury emerged as the primary research areas, with "apoptosis," "signaling pathway," and "oxidative stress" as the main keywords of research hotspots.

Conclusions

This study provides a thorough overview of research trends and focal points in skeletal muscle I/R injury by applying bibliometric and visualization techniques. The insights gained from our findings offer a profound understanding of the evolving landscape of skeletal muscle I/R injury research, thereby functioning as a valuable reference and roadmap for future investigations.

GQ262 Attenuates Pathological Cardiac Remodeling by Downregulating the Akt/mTOR Signaling Pathway

Cardiac remodeling, a critical process that can lead to heart failure, is primarily characterized by cardiac hypertrophy. Studies have shown that transgenic mice with Gαq receptor blockade exhibit reduced hypertrophy under induced pressure overload. GQ262, a novel Gαq/11 inhibitor, has demonstrated good biocompatibility and specific inhibitory effects on Gαq/11 compared to other inhibitors. However, its role in cardiac remodeling remains unclear. This study aims to explore the anti-cardiac remodeling effects and mechanisms of GQ262 both in vitro and in vivo, providing data and theoretical support for its potential use in treating cardiac remodeling diseases. Cardiac hypertrophy was induced in mice via transverse aortic constriction (TAC) for 4 weeks and in H9C2 cells through phenylephrine (PE) induction, confirmed with WGA and H&E staining. We found that GQ262 improved cardiac function, inhibited the protein and mRNA expression of hypertrophy markers, and reduced the levels of apoptosis and fibrosis. Furthermore, GQ262 inhibited the Akt/mTOR signaling pathway activation induced by TAC or PE, with its therapeutic effects disappearing upon the addition of the Akt inhibitor ARQ092. These findings reveal that GQ262 inhibits cardiomyocyte hypertrophy and apoptosis through the Akt/mTOR signaling pathway, thereby reducing fibrosis levels and mitigating cardiac remodeling.

Protective effect of salvianolic acid B against myocardial ischemia/reperfusion injury: preclinical systematic evaluation and meta-analysis

Background

Salvianolic acid B is the most abundant water-soluble component in the traditional Chinese medicine Danshen and can reduce myocardial ischemia-reperfusion (MI/R) injury through multiple targets and pathways. However, the role of SalB in protecting the myocardium from ischemia/reperfusion injury remains unclear.

Purpose

To perform a preclinical systematic review and meta-analysis to assess the efficacy of Sal B in an animal model of myocardial infarction/reperfusion (MI/R) and to summarize the potential mechanisms of Sal B against MI/R.

Methods

Studies published from inception to March 2024 were systematically searched in PubMed, Web of Science, Embase, China National Knowledge Infrastructure Wanfang, and VIP databases. The methodological quality was determined using the SYRCLE RoB tool. The R software was used to analyze the data. The potential mechanisms are categorized and summarized.

Results

32 studies containing 732 animals were included. The results of the meta-analysis showed that Sal B reduced myocardial infarct size (p < 0.01), and the cardiological indices of CK-MB (p < 0.01), CK (p < 0.01), LDH (p < 0.01), and cTnI (p < 0.01) compared to the control group. In addition, Sal B increased cardiac function indices, such as LVFS (p < 0.01), -dp/dt max (p < 0.01), +dp/dt max (p < 0.01), and cardiac output (p < 0.01). The protective effects of Sal B on the myocardium after I/R may be mediated by attenuating oxidative stress and inflammation, promoting neovascularization, regulating vascular function, and attenuating cardiac myocyte apoptosis. Publication bias was observed in all the included studies. Further studies are required to elucidate the extent of the cardioprotective effects of SalB and the safety of its use.

Conclusion

To the best of our knowledge, this is the first meta-analysis of Sal B in the treatment of MI/R injury, and Sal B demonstrated a positive effect on MI/R injury through the modulation of key pathological indicators and multiple signaling pathways. Further studies are needed to elucidate the extent to which SalB exerts its cardioprotective effects and the safety of its use.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/.

Acid sphingomyelinase inhibition induces cerebral angiogenesis post-ischemia/reperfusion in an oxidative stress-dependent way and promotes endothelial survival by regulating mitochondrial metabolism

Acid sphingomyelinase (ASM) inhibitors are widely used for the treatment of post-stroke depression. They promote neurological recovery in animal stroke models via neurorestorative effects. In a previous study, we found that antidepressants including amitriptyline, fluoxetine, and desipramine increase cerebral angiogenesis post-ischemia/reperfusion (I/R) in an ASM-dependent way. To elucidate the underlying mechanisms, we investigated the effects of the functional ASM inhibitor amitriptyline in two models of I/R injury, that is, in human cerebral microvascular endothelial hCMEC/D3 cells exposed to oxygen-glucose deprivation and in mice exposed to middle cerebral artery occlusion (MCAO). In addition to our earlier studies, we now show that amitriptyline increased mitochondrial reactive oxygen species (ROS) formation in hCMEC/D3 cells and increased ROS formation in the vascular compartment of MCAO mice. ROS formation was instrumental for amitriptyline's angiogenic effects. ROS formation did not result in excessive endothelial injury. Instead, amitriptyline induced a profound metabolic reprogramming of endothelial cells that comprised reduced endothelial proliferation, reduced mitochondrial energy metabolism, reduced endoplasmic reticulum stress, increased autophagy/mitophagy, stimulation of antioxidant responses and inhibition of apoptotic cell death. Specifically, the antioxidant heme oxygenase-1, which was upregulated by amitriptyline, mediated amitriptyline's angiogenic effects. Thus, heme oxygenase-1 knockdown severely compromised angiogenesis and abolished amitriptyline's angiogenic responses. Our data demonstrate that ASM inhibition reregulates a complex network of metabolic and mitochondrial responses post-I/R that contribute to cerebral angiogenesis without compromising endothelial survival.

Inhibiting H2AX Can Ameliorate Myocardial Ischemia/Reperfusion Injury by Regulating P53/JNK Signaling Pathway

Myocardial ischemia-reperfusion (I/R) injury is a significant area of focus in cardiovascular disease research. I/R injury can increase intracellular oxidative stress, leading to DNA damage. H2AX plays a crucial role in DNA repair. This study utilized mouse and cell models of myocardial I/R to investigate the impact of H2AX on cardiomyocytes during I/R. This study initially assessed the expression of H2AX in MI/R mice compared to a sham surgery group. Subsequently, cardiac function, infarct area, and mitochondrial damage were evaluated after inhibiting H2AX in MI/R mice and a negative control group. Furthermore, the study delved into the molecular mechanisms by analyzing the expression of H2AX, P53, p-JNK, SHP2, p-SHP2, p-RAS, parkin, Drp1, Cyt-C, Caspase-3, and Caspase-8 in cardiomyocytes following the addition of JNK or P53 agonists. The results from western blotting in vivo indicated significantly higher H2AX expression in the MI/R group compared to the sham group. Inhibiting H2AX improved cardiac function, reduced myocardial infarct area, and mitigated mitochondrial damage in the MI/R group. In vitro experiments demonstrated that inhibiting H2AX could attenuate mitochondrial damage and apoptosis in myocardial cells by modulating the P53 and JNK signaling pathways. These findings suggested that inhibiting H2AX may alleviate myocardial I/R injury through the regulation of the P53/JNK pathway, highlighting H2AX as a potential target for the treatment of myocardial ischemia/reperfusion injury.

TRIM55 Aggravates Cardiomyocyte Apoptosis After Myocardial Infarction via Modulation of the Nrf2/HO-1 Pathway

Tripartite motif-containing 55 (Trim55) is mainly expressed in myocardium and skeletal muscle, which plays an important role in promoting the embryonic development of the mouse heart. We investigated the role of Trim55 in myocardial infarction and the associated molecular mechanisms. We studied both gain and loss of function in vivo and in vitro. The results showed that Trim55 knockout improved cardiac function and apoptosis after myocardial infarction, and overexpression aggravated cardiac function damage. The mechanism is that Trim55 interacts with nuclear factor, erythroid derived 2 (Nrf2) to accelerate its degradation and inhibit the expression of heme oxygenase 1, thereby promoting cardiomyocyte apoptosis.

Effects of Neonatal Administration of Non-Opiate Analogues of Leu-Enkephalin on the Delayed Cardiac Consequences of Intrauterine Hypoxia

Intrauterine hypoxia (gestation days 15-19, pO2 65 mm Hg, duration 4 h) led to an increase in the expression of p53, beclin-1, endothelial NO synthase (eNOS), and caspase-3 proteins in cardiomyocytes and reduced the number of mast cells in the heart of 60-day-old albino rats. Administration of a non-opiate analogue of leu-enkephalin (NALE peptide: Phe-D-Ala-Gly-Phe-Leu-Arg, 100 μg/kg) on days 2-6 of the neonatal period decreased the severity of delayed posthypoxic myocardial reaction. The content of eNOS+ cardiomyocytes and the total number of mast cells of these animals did not differ from the control parameters; the content of p53+ cardiomyocytes was significantly lower than in animals exposed to intrauterine hypoxia. The cardioprotective activity of NALE was partially neutralized by co-administration with the NO synthase inhibitor (L-NAME, 50 mg/kg). Correction of the delayed posthypoxic changes, similar to the effects of NALE peptide, was observed after neonatal administration of its arginine-free analogue, G peptide (Phe-D-Ala-Gly-Phe-Leu-Gly; 100 μg/kg). Non-opiate analogues of leu-enkephalin NALE and G peptides can be considered as promising substances capable of preventing long-term cardiac consequences of intrauterine hypoxia.

The benefits of oral glucose-lowering agents: GLP-1 receptor agonists, DPP-4 and SGLT-2 inhibitors on myocardial ischaemia/reperfusion injury

Myocardial infarction (MI) is a life-threatening cardiovascular disease that, on average, results in 8.5 million deaths worldwide each year. Timely revascularization of occluded vessels is a critical method of myocardial salvage. However, reperfusion paradoxically leads to the worsening of myocardial damage known as myocardial ischaemia/reperfusion injury (MI/RI). Therefore, reducing the size of myocardial infarction after reperfusion is critical and remains an important therapeutic goal. The susceptibility of the myocardium to MI/RI may be increased by diabetes. Currently, some traditional antidiabetic agents such as metformin reduce MI/RI by decreasing inflammation, inhibiting oxidative stress, and improving vascular endothelial function. This appears to be a new direction for the treatment of MI/RI. Recent cardiovascular outcome trials have shown that several oral antidiabetic agents, including glucagon-like peptide-1 receptor agonists (GLP-1RAs), dipeptidyl peptidase-4 inhibitors (DPP-4is), and sodium-glucose-linked transporter-2 inhibitors (SGLT-2is), not only have good antidiabetic effects but also have a protective effect on myocardial protection. This article aims to discuss the mechanisms and effects of oral antidiabetic agents, including GLP-1RAs, DPP-4is, and SGLT-2is, on MI/RI to facilitate their clinical application.

Is There a Mitochondrial Protection via Remote Ischemic Conditioning in Settings of Anticancer Therapy Cardiotoxicity?

PURPOSE OF REVIEW

To provide an overview of (a) protective effects on mitochondria induced by remote ischemic conditioning (RIC) and (b) mitochondrial damage caused by anticancer therapy. We then discuss the available results of studies on mitochondrial protection via RIC in anticancer therapy-induced cardiotoxicity.

RECENT FINDINGS

In three experimental studies in healthy mice and pigs, there was a RIC-mediated protection against anthracycline-induced cardiotoxicity and there was some evidence of improved mitochondrial function with RIC. The RIC-mediated protection was not confirmed in the two available studies in cancer patients. In adult cancer patients, RIC was associated with an adverse outcome. There are no data on mitochondrial function in cancer patients. Studies in tumor-bearing animals are needed to determine whether RIC does not interfere with the anticancer properties of the drugs and whether RIC actually improves mitochondrial function, ultimately resulting in improved cardiac function.

LDHA contributes to nicotine induced cardiac fibrosis through autophagy flux impairment

Cardiac fibrosis is a typical feature of cardiac pathological remodeling, which is associated with adverse clinical outcomes and has no effective therapy. Nicotine is an important risk factor for cardiac fibrosis, yet its underlying molecular mechanism remains poorly understood. This study aimed to identify its potential molecular mechanism in nicotine-induced cardiac fibrosis. Our results showed nicotine exposure led to the proliferation and transformation of cardiac fibroblasts (CFs) into myofibroblasts (MFs) by impairing autophagy flux. Through the use of drug affinity responsive target stability (DARTS) assay, cellular thermal shift assay (CETSA), and surface plasmon resonance (SPR) technology, it was discovered that nicotine directly increased the stability and protein levels of lactate dehydrogenase A (LDHA) by binding to it. Nicotine treatment impaired autophagy flux by regulating the AMPK/mTOR signaling pathway, impeding the nuclear translocation of transcription factor EB (TFEB), and reducing the activity of cathepsin B (CTSB). In vivo, nicotine treatment exacerbated cardiac fibrosis induced in spontaneously hypertensive rats (SHR) and worsened cardiac function. Interestingly, the absence of LDHA reversed these effects both in vitro and in vivo. Our study identified LDHA as a novel nicotine-binding protein that plays a crucial role in mediating cardiac fibrosis by blocking autophagy flux. The findings suggest that LDHA could potentially serve as a promising target for the treatment of cardiac fibrosis.

The role of autophagy in the progression of HIV infected cardiomyopathy

Although highly active antiretroviral therapy (HAART) has changed infection with human immunodeficiency virus (HIV) from a diagnosis with imminent mortality to a chronic illness, HIV positive patients who do not develop acquired immunodeficiency syndrome (AIDs) still suffer from a high rate of cardiac dysfunction and fibrosis. Regardless of viral load and CD count, HIV-associated cardiomyopathy (HIVAC) still causes a high rate of mortality and morbidity amongst HIV patients. While this is a well characterized clinical phenomena, the molecular mechanism of HIVAC is not well understood. In this review, we consolidate, analyze, and discuss current research on the intersection between autophagy and HIVAC. Multiple studies have linked dysregulation in various regulators and functional components of autophagy to HIV infection regardless of mode of viral entry, i.e., coronary, cardiac chamber, or pericardial space. HIV proteins, including negative regulatory factor (Nef), glycoprotein 120 (gp120), and transactivator (Tat), have been shown to interact with type II microtubule-associated protein-1 β light chain (LC3-II), Rubiquitin, SQSTM1/p62, Rab7, autophagy-specific gene 7 (ATG7), and lysosomal-associated membrane protein 1 (LAMP1), all molecules critical to normal autophagy. HIV infection can also induce dysregulation of mitochondrial bioenergetics by altering production and equilibrium of adenosine triphosphate (ATP), mitochondrial reactive oxygen species (ROS), and calcium. These changes alter mitochondrial mass and morphology, which normally trigger autophagy to clear away dysfunctional organelles. However, with HIV infection also triggering autophagy dysfunction, these abnormal mitochondria accumulate and contribute to myocardial dysfunction. Likewise, use of HAART, azidothymidine and Abacavir, have been shown to induce cardiac dysfunction and fibrosis by inducing abnormal autophagy during antiretroviral therapy. Conversely, studies have shown that increasing autophagy can reduce the accumulation of dysfunctional mitochondria and restore cardiomyocyte function. Interestingly, Rapamycin, a mammalian target of rapamycin (mTOR) inhibitor, has also been shown to reduce HIV-induced cytotoxicity by regulating autophagy-related proteins, making it a non-antiviral agent with the potential to treat HIVAC. In this review, we synthesize these findings to provide a better understanding of the role autophagy plays in HIVAC and discuss the potential pharmacologic targets unveiled by this research.

The pathological mechanisms and potential therapeutic drugs for myocardial ischemia reperfusion injury

BACKGROUND

Cardiovascular disease is the main cause of death and disability, with myocardial ischemia being the predominant type that poses a significant threat to humans. Reperfusion, an essential therapeutic approach, promptly reinstates blood circulation to the ischemic myocardium and stands as the most efficacious clinical method for myocardial preservation. Nevertheless, the restoration of blood flow associated with this process can potentially induce myocardial ischemia-reperfusion injury (MIRI), thereby diminishing the effectiveness of reperfusion and impacting patient prognosis. Therefore, it is of great significance to prevent and treat MIRI.

PURPOSE

MIRI is an important factor affecting the prognosis of patients, and there is no specific in-clinic treatment plan. In this review, we have endeavored to summarize its pathological mechanisms and therapeutic drugs to provide more powerful evidence for clinical application.

METHODS

A comprehensive literature review was conducted using PubMed, Web of Science, Embase, Medline and Google Scholar with a core focus on the pathological mechanisms and potential therapeutic drugs of MIRI.

RESULTS

Accumulated evidence revealed that oxidative stress, calcium overload, mitochondrial dysfunction, energy metabolism disorder, ferroptosis, inflammatory reaction, endoplasmic reticulum stress, pyroptosis and autophagy regulation have been shown to participate in the process, and that the occurrence and development of MIRI are related to plenty of signaling pathways. Currently, a range of chemical drugs, natural products, and traditional Chinese medicine (TCM) preparations have demonstrated the ability to mitigate MIRI by targeting various mechanisms.

CONCLUSIONS

At present, most of the research focuses on animal and cell experiments, and the regulatory mechanisms of each signaling pathway are still unclear. The translation of experimental findings into clinical practice remains incomplete, necessitating further exploration through large-scale, multi-center randomized controlled trials. Given the absence of a specific drug for MIRI, the identification of therapeutic agents to reduce myocardial ischemia is of utmost significance. For the future, it is imperative to enhance our understanding of the pathological mechanism underlying MIRI, continuously investigate and develop novel pharmaceutical agents, expedite the clinical translation of these drugs, and foster innovative approaches that integrate TCM with Western medicine. These efforts will facilitate the emergence of fresh perspectives for the clinical management of MIRI.

Sephin1 enhances integrated stress response and autophagy to alleviate myocardial ischemia-reperfusion injury in mice

OBJECTIVE

Integrated stress response (ISR) is activated to promote cell survival by maintaining the phosphorylation of eukaryotic translation initiation factor 2 (eIF2α). We investigated whether Sephin1 enhances ISR and attenuates myocardial ischemia-reperfusion (MIR) injury.

METHODS

Male C57BL/6 J mice were injected with Sephin1 (2 mg/kg,i.p.) 30 min before surgery to establish a model of MIR with 45 min ischemia and 180 min reperfusion. In vitro, the H9C2 cell line with hypoxia-reoxygenation (H/R) was used to simulate MIR. Myocardial injury was evaluated by echocardiography, histologic observation after staining with TTC and H&E and electron microscopy. ISR, autophagy and apoptosis in vivo and in vitro were evaluated by immunoblotting, immunohistochemistry, immunofluorescence, and flow cytometry, respectively. Global protein synthesis was determined using a non-radioactive SUnSET Assay based on the puromycin method. Autophinib, an autophagy-specific inhibitor, was used to investigate the correlation between autophagy and apoptosis in the presence of Sephin1.

RESULTS

In vivo, Sephin1 significantly reduced myocardial injury and improved the cardiac function in MIR mice. Sephin1 administration prolonged ISR, reduced cell apoptosis, and promoted autophagy. In vitro, Sephin1 increased the number of stress granules (SGs) and autophagic vesicles, enhanced ISR and related protein synthesis suppression, and reduced cell apoptosis. Autophinib partly reversed autophagosome formation and apoptosis in H9c2 cells.

CONCLUSIONS

Sephin1 enhances ISR and related protein synthesis suppression, ameliorates myocardial apoptosis, and promotes autophagy during MIR stress. Sephin1 could act as a noval ISR enhancer for managing acute myocardial ischemia disease.

Knockdown of SDCBP induces autophagy to promote cardiomyocyte growth and angiogenesis in hypoxia/reoxygenation model

OBJECTIVE

Angina, myocardial infarction, and even mortality can result from myocardial ischemia (MI). Angiogenesis facilitates tissue repair, lessens cell damage, and ensures that ischemic tissues receive blood and oxygen. This study investigated the possible mechanism of syndecan-binding protein (SDCBP) on autophagy and assessed its impact on myocardial ischemia.

METHOD

A cardiac hypoxia-reoxygenation (H/R) cell model was created for this investigation. Flow cytometry, the cell counting kit-8, and Western blotting were used to measure the damage to cardiomyocytes. Western blotting and immunofluorescence were used to quantify autophagy. Furthermore, assays for tube formation, migration, and Western blotting were used to assess angiogenic capacity. Additionally, the EGFR-PI3K-Akt signaling pathway's activation was found using Western blotting.

RESULT

In the H/R-induced cardiomyocyte model, there is a rise in the expression of SDCBP. Treatment with H/R markedly boosted apoptosis and considerably decreased cell survival. H/R induction strongly inhibits autophagy, increases P62 expression, and decreases LC3II/I expression. Moreover, H/R induction dramatically reduced the ability to form tubes, migrate, and express VEGF, all of which prevented cell angiogenesis. Furthermore, EGFR-PI3K-Akt signaling pathway expression is strongly inhibited by H/R induction. considerable reduction of H/R-induced cell damage, considerable inhibition of apoptosis, promotion autophagy and angiogenesis, and activation of the EGFR-PI3K-Akt signaling pathway are all possible with SDCBP knockdown.

CONCLUSION

To summarize, this study demonstrates that via stimulating the EGFR-PI3K-Akt signaling pathway, SDCBP knockdown may mitigate the effects of H/R-induced cardiomyocyte death and encourage autophagy and blood vessel formation. A theoretical foundation for possible myocardial infarction treatment is thus provided.

Therapeutic Potential of Hydrogen Sulfide in Ischemia and Reperfusion Injury

Ischemia-reperfusion (I/R) injury, a prevalent pathological condition in medical practice, presents significant treatment challenges. Hydrogen sulfide (H2S), acknowledged as the third gas signaling molecule, profoundly impacts various physiological and pathophysiological processes. Extensive research has demonstrated that H2S can mitigate I/R damage across multiple organs and tissues. This review investigates the protective effects of H2S in preventing I/R damage in the heart, brain, liver, kidney, intestines, lungs, stomach, spinal cord, testes, eyes, and other tissues. H2S provides protection against I/R damage by alleviating inflammation and endoplasmic reticulum stress; inhibiting apoptosis, oxidative stress, and mitochondrial autophagy and dysfunction; and regulating microRNAs. Significant advancements in understanding the mechanisms by which H2S reduces I/R damage have led to the development and synthesis of H2S-releasing agents such as diallyl trisulfide-loaded mesoporous silica nanoparticles (DATS-MSN), AP39, zofenopril, and ATB-344, offering a new therapeutic avenue for I/R injury.

Antioxidant and anti-Alzheimer's disease activities of 1,8-cineole and its cyclodextrin inclusion complex

1,8-Cineole is a bicyclic monoterpene widely distributed in the essential oils of various medicinal plants, and it exhibits significant anti-inflammatory and antioxidant activities. We aimed to investigate the therapeutic effect of 1,8-cineole on anti-Alzheimer's disease by using transgenic Caenorhabditis elegans models. Our studies demonstrated that 1,8-cineole significantly relieved Aβ1-42-induced paralysis and exhibited remarkable antioxidant and anti-Aβ1-42 aggregation activities in transgenic nematodes CL4176, CL2006 and CL2355. We developed a 1,8-cineole/cyclodextrin inclusion complex, displaying enhanced anti-paralysis, anti-Aβ aggregation and antioxidant activities compared to 1,8-cineole. In addition, we found 1,8-cineole treatment activated the SKN-1/Nrf-2 pathway and induced autophagy in nematodes. Our results demonstrated the antioxidant and anti-Alzheimer's disease activities of 1,8-cineole, which provide a potential therapeutic approach for Alzheimer's disease.

Crosstalk among Reactive Oxygen Species, Autophagy and Metabolism in Myocardial Ischemia and Reperfusion Stages

Myocardial ischemia is the most common cardiovascular disease. Reperfusion, an important myocardial ischemia tool, causes unexpected and irreversible damage to cardiomyocytes, resulting in myocardial ischemia/reperfusion (MI/R) injury. Upon stress, especially oxidative stress induced by reactive oxygen species (ROS), autophagy, which degrades the intracellular energy storage to produce metabolites that are recycled into metabolic pathways to buffer metabolic stress, is initiated during myocardial ischemia and MI/R injury. Excellent cardioprotective effects of autophagy regulators against MI and MI/R have been reported. Reversing disordered cardiac metabolism induced by ROS also exhibits cardioprotective action in patients with myocardial ischemia. Herein, we review current knowledge on the crosstalk between ROS, cardiac autophagy, and metabolism in myocardial ischemia and MI/R. Finally, we discuss the possible regulators of autophagy and metabolism that can be exploited to harness the therapeutic potential of cardiac metabolism and autophagy in the diagnosis and treatment of myocardial ischemia and MI/R.

Maximakinin reversed H2O2 induced oxidative damage in rat cardiac H9c2 cells through AMPK/Akt and AMPK/ERK1/2 signaling pathways

Maximakinin (MK), a homolog of bradykinin (BK), is extracted from skin venom of the Chinese toad Bombina maxima. Although MK has a good antihypertensive effect, its effect on myocardial cells is unclear. This study investigates the protective effect of MK on hydrogen peroxide (H2O2)-induced oxidative damage in rat cardiac H9c2 cells and explores its mechanism of action. A 3-(4,5-Dimethyl-2-Thiazolyl)-2,5-Diphenyl Tetrazolium Bromide (MTT) assay was selected to detect the effect of MK on H9c2 cell viability, while flow cytometry was used to investigate the influence of MK and H2O2 on intracellular reactive oxygen species (ROS) levels. Protein expression changes were detected by western blot. In addition, specific protein inhibitors were applied to confirm the induction of ROS-related signaling pathways by MK. MTT assay results show that MK significantly reversed H2O2-induced cell growth inhibition. Flow cytometry Dichlorodihydrofluorescein diacetate (DCFH-DA) staining shows that MK significantly reversed H2O2-induced increases in intracellular ROS production in H9c2 cells. Moreover, the addition of specific protein inhibitors suggests that MK reverses H2O2-induced oxidative damage by activating AMP-activated protein kinase (AMPK)/protein kinase B (Akt) and AMPK/extracellular-regulated kinase 1/2 (ERK1/2) pathways. Finally, an inhibitor of bradykinin B2 receptors (B2Rs), HOE-140, was applied to investigate potential targets of MK in H9c2 cells. HOE-140 significantly blocked induction of AMPK/Akt and AMPK/ERK1/2 pathways by MK, suggesting a potentially important role for B2Rs in MK reversing H2O2-induced oxidative damage. Above all, MK protects against oxidative damage by inhibiting H2O2-induced ROS production in H9c2 cells. The protective mechanism of MK may be achieved by activation of B2Rs to activate downstream AMPK/Akt and AMPK/ERK1/2 pathways.

Peptides Are Cardioprotective Drugs of the Future: The Receptor and Signaling Mechanisms of the Cardioprotective Effect of Glucagon-like Peptide-1 Receptor Agonists

The high mortality rate among patients with acute myocardial infarction (AMI) is one of the main problems of modern cardiology. It is quite obvious that there is an urgent need to create more effective drugs for the treatment of AMI than those currently used in the clinic. Such drugs could be enzyme-resistant peptide analogs of glucagon-like peptide-1 (GLP-1). GLP-1 receptor (GLP1R) agonists can prevent ischemia/reperfusion (I/R) cardiac injury. In addition, chronic administration of GLP1R agonists can alleviate the development of adverse cardiac remodeling in myocardial infarction, hypertension, and diabetes mellitus. GLP1R agonists can protect the heart against oxidative stress and reduce proinflammatory cytokine (IL-1β, TNF-α, IL-6, and MCP-1) expression in the myocardium. GLP1R stimulation inhibits apoptosis, necroptosis, pyroptosis, and ferroptosis of cardiomyocytes. The activation of the GLP1R augments autophagy and mitophagy in the myocardium. GLP1R agonists downregulate reactive species generation through the activation of Epac and the GLP1R/PI3K/Akt/survivin pathway. The GLP1R, kinases (PKCε, PKA, Akt, AMPK, PI3K, ERK1/2, mTOR, GSK-3β, PKG, MEK1/2, and MKK3), enzymes (HO-1 and eNOS), transcription factors (STAT3, CREB, Nrf2, and FoxO3), KATP channel opening, and MPT pore closing are involved in the cardioprotective effect of GLP1R agonists.

Artesunate Alleviates Kidney Fibrosis in Type 1 Diabetes with Periodontitis Rats via Promoting Autophagy and Suppression of Inflammation

To explore the effect of periodontal disease on the progression of diabetic kidney disease (DKD), to observe the effects of artesunate (ART) intervention on periodontal and kidney tissues in type 1 diabetic rats with periodontitis, and to explore the possibility of ART for the treatment of DKD. Rat models of diabetes mellitus, periodontitis, and diabetes mellitus with periodontitis were established through streptozotocin (STZ) intraperitoneal injection, maxillary first molar ligation, and P. gingivalis ligation applied sequentially. Ten weeks after modeling, ART gavage treatment was given for 4 weeks. Immunohistochemistry, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and Western blot were used to investigate the inflammatory factors, fibrogenisis, autophagy-related factors, and proteins in periodontal and kidney tissues, and 16S rDNA sequencing was used to detect the changes in dental plaque fluid and kidney tissue flora. Compared to the control group, the protein expression levels of transforming growth factor β1 (TGF-β1) and COL-IV in the periodontal disease (PD) group were increased. The protein expression of TGF-β1, Smad3, and COL-IV increased in the DM group and the DM + PD group, and the expression of TGF-β1, Smad3, and COL-IV was upregulated in the DM + PD group. These results suggest that periodontal disease enhances renal fibrosis and that this process is related to the TGF-β1/Smad/COL-IV signaling pathway. Among the top five dominant bacteria in the kidney of the DM + PD group, the abundance of Proteobacteria increased most significantly, followed by Actinobacteria and Firmicutes with mild increases. The relative abundance of Proteobacteria, Actinobacteria, and Firmicutes in the kidney tissues of DM and PD groups also showed an increasing trend compared with the CON group. Proteobacteria and Firmicutes in the kidney of the PD group and DM + PD group showed an increasing trend, which may mediate the increase of oxidative stress in the kidney and promote the occurrence and development of DN. Periodontal disease may lead to an imbalance of renal flora, aggravate renal damage in T1DM, cause glomerular inflammation and renal tubulointerstitial fibrosis, and reduce the level of autophagy. ART delays the process of renal fibrosis by inhibiting the TGF-β-Smad signaling pathway.

Effects of H2S-donor ascorbic acid derivative and ischemia/reperfusion-induced injury in isolated rat hearts

Hydrogen sulfide (H2S), a gasotransmitter, plays a crucial role in vasorelaxation, anti-inflammatory processes and mitigating myocardial ischemia/reperfusion-induced injury by regulating various signaling processes. We designed a water soluble H2S-releasing ascorbic acid derivative, BM-164, to combine the beneficial cardiovascular and anti-inflammatory effects of H2S with the excellent water solubility and antioxidant properties of ascorbic acid. DPPH antioxidant assay revealed that the antioxidant activity of BM-164 in the presence of a myocardial tissue homogenate (extract) increased continuously over the 120 min test interval due to the continuous release of H2S from BM-164. The cytotoxicity of BM-164 was tested by MTT assay on H9c2 cells, which resulted in no cytotoxic effect at concentrations of 10 to 30 μM. The possible beneficial effects of BM-164 (30 µM) was examined in isolated 'Langendorff' rat hearts. The incidence of ventricular fibrillation (VF) was significantly reduced from its control value of 79 % to 31 % in the BM-164 treated group, and the infarct size was also diminished from the control value of 28 % to 14 % in the BM-164 treated group. However, coronary flow (CF) and heart rate (HR) values in the BM-164 treated group did not show significantly different levels in comparison with the drug-free control, although a non-significant recovery in both CF and HR was observed at each time point. We attempted to reveal the mechanism of action of BM-164, focusing on the processes of autophagy and apoptosis. The expression of key autophagic and apoptotic markers in isolated rat hearts were detected by Western blot analysis. All the examined autophagy-related proteins showed increased expression levels in the BM-164 treated group in comparison to the drug-free control and/or ascorbic acid treated groups, while the changes in the expression of apoptotic markers were not obvious. In conclusion, the designed water soluble H2S releasing ascorbic acid derivative, BM-164, showed better cardiac protection against ischemia/reperfusion-induced injury compared to the untreated and ascorbic acid treated hearts, respectively.

Hippo (YAP)-autophagy axis protects against hepatic ischemia-reperfusion injury through JNK signaling

BACKGROUND

Hepatic ischemia-reperfusion injury (HIRI) remains a common complication during liver transplantation (LT) in patients. As a key downstream effector of the Hippo pathway, Yes-associated protein (YAP) has been reported to be involved in various physiological and pathological processes. However, it remains elusive whether and how YAP may control autophagy activation during ischemia-reperfusion.

METHODS

Human liver tissues from patients who had undergone LT were obtained to evaluate the correlation between YAP and autophagy activation. Both an in vitro hepatocyte cell line and in vivo liver-specific YAP knockdown mice were used to establish the hepatic ischemia-reperfusion models to determine the role of YAP in the activation of autophagy and the mechanism of regulation.

RESULTS

Autophagy was activated in the post-perfusion liver grafts during LT in patients, and the expression of YAP positively correlated with the autophagic level of hepatocytes. Liver-specific knockdown of YAP inhibited hepatocytes autophagy upon hypoxia-reoxygenation and HIRI ( P <0.05). YAP deficiency aggravated HIRI by promoting the apoptosis of hepatocytes both in the in vitro and in vivo models ( P <0.05). Attenuated HIRI by overexpression of YAP was diminished after the inhibition of autophagy with 3-methyladenine. In addition, inhibiting autophagy activation by YAP knockdown exacerbated mitochondrial damage through increasing reactive oxygen species ( P <0.05). Moreover, the regulation of autophagy by YAP during HIRI was mediated by AP1 (c-Jun) N-terminal kinase (JNK) signaling through binding to the transcriptional enhanced associate domain (TEAD).

CONCLUSIONS

YAP protects against HIRI by inducing autophagy via JNK signaling that suppresses the apoptosis of hepatocytes. Targeting Hippo (YAP)-JNK-autophagy axis may provide a novel strategy for the prevention and treatment of HIRI.

The SNHG10-miR-495-3p-PTEN axis is involved in sevoflurane-mediated protective effects in cardiomyocytes against hypoxia/reoxygenation injury

Myocardial infarction (MI) has been considered a leading cause of death worldwide. Relieving ischemia-reperfusion myocardial damage is one of the major roles in treating MI. Sevoflurane postconditioning provides myocardial protection, and this study probes the mechanism of sevoflurane-mediated protective effects. A hypoxia/reoxygenation (H/R) model was constructed in cardiomyocytes, which were pretreated with 2.4% sevoflurane. Alterations in SNHG10, miR-495-3p, and PTEN levels were determined, and gain- or loss-of functional assays were conducted to confirm the role of the SNHG10/miR-495-3p axis, which is potentially regulated by sevoflurane. Cell viability, oxidative stress, and inflammatory reactions were all evaluated. The results indicated that sevoflurane post-conditioning attenuated H/R-induced cardiomyocyte damage and reduced the SHNH10 level. SNHG10 overexpression reversed sevoflurane-mediated protective effects on cardiomyocytes. Moreover, SNHG10 targeted miR-495-3p and restrained its expression, while miR-495-3p targeted PTEN, suppressed PTEN levels, and promoted HIF-1α expression. miR-495-3p overexpression decreased SNHG10-mediated myocardial injury and enhanced HIF-1α levels. However, no additional protection was found when sevoflurane was administered to H/R-exposed cardiomyocytes following treatment with the HIF-1α inhibitor LW6. Overall, sevoflurane protects cardiomyocytes from H/R by modulating the SNHG10-miR-495-3p-PTEN-HIF-1α axis.

Endothelial Cell Apoptosis but Not Necrosis Is Inhibited by Ischemic Preconditioning

This study aimed to assess the influence of ischemic preconditioning (IP) on hypoxia/reoxygenation (HR)-induced endothelial cell (EC) death. Human umbilical vein endothelial cells (HUVECs) were subjected to 2 or 6 h hypoxia with subsequent reoxygenation. IP was induced by 20 min of hypoxia followed by 20 min of reoxygenation. Necrosis was assessed by the release of lactate dehydrogenase (LDH) and apoptosis by double staining with propidium iodide/annexin V (PI/AV), using TUNEL test, and Bcl-2 and Bax gene expression measured using RT-PCR. In PI/AV staining, after 24 h of reoxygenation, 30-33% of EC were necrotic and 16-21% were apoptotic. In comparison to HR cells, IP reduced membrane apoptosis after 24 h of reoxygenation by 50% but did not influence EC necrosis. Nuclear EC apoptosis affected about 15-17% of EC after 24 h of reoxygenation and was reduced with IP by 55-60%. IP was associated with a significantly higher Bcl-2/Bax ratio, at 8 h 2-4 times and at 24 h 2-3 times as compared to HR. Longer hypoxia was associated with lower values of Bcl-2/Bax ratio in EC subjected to HR or IP. IP delays, without reducing, the extent of HR-induced EC necrosis but significantly inhibits their multi-level evaluated apoptosis.

Systematic review and meta-analysis of the interventional effects of resveratrol in a rat model of myocardial ischemia-reperfusion injury

Objective: To evaluate the intervention effect of resveratrol on rat model of myocardial ischemia-reperfusion injury. Methods: The relevant studies on the intervention of resveratrol on rat models of myocardial ischemia reperfusion injury were searched in PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), Wanfang and China Science and Technology Journal Database from the start of database establishment to January 2023. Data were extracted from studies that met the inclusion criteria. The results included electrocardiogram (ECG) and myocardial injury markers: ST changes, cardiac troponin I (cTn-I), cardiac troponin T (cTn-T), creatine kinase (CK), creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH); hemodynamic indicators: heart rate (HR), left ventricular diastolic pressure (LVDP), left ventricular end-diastolic pressure (LVEDP), left ventricular systolic pressure (LVSP), maximum rate of increase of left ventricular pressure (+dp/dtmax), maximum rate of decrease of left ventricular pressure (-dp/dtmax); oxidative damage indicators: nitric oxide (NO), reactive oxygen species (ROS), superoxide dismutase (SOD), malondialdehyde (MDA); inflammatory factors: tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6); apoptosis index: B-cell lymphoma-2 (Bcl-2), BCL2-Associated X (Bax), cardiomyocyte apoptosis index (AI); heart tissue structure: myocardial infarction size. Finally, a meta-analysis of these results was conducted. The methodological quality of the studies was assessed using the SYRCLE Bias Risk tool. Results: A total of 43 studies were included in the meta-analysis, and the quality of the included studies was assessed. It was found that the evidence quality of these 43 studies was low, and no study was judged to have low risk bias in all risk assessments. The results showed that resveratrol could reduce ST segment, cTn-I, cTn-T, CK, CK-MB, LDH, LVEDP, ROS, MDA, TNF-α, IL-6, AI levels and myocardial infarction size. HR, LVDP, LVSP, +dp/dtmax, NO, Bcl-2, and SOD levels were increased. However, resveratrol had no significant effect on -dp/dtmax and Bax outcome measures. Conclusion: Resveratrol can reduce ST segment in rat model of myocardial ischemia-reperfusion injury, alleviate myocardial injury, improve ventricular systolic and diastolic ability in hemodynamics, reduce inflammatory response and oxidative damage, and reduce myocardial necrosis and apoptosis. Due to the low quality of the methodologies included in the studies, additional research is required.

Serum Glucocorticoid-Regulated Kinase-1 in Ischemia-Reperfusion Injury: Blessing or Curse

The family of serum-glucocorticoid-regulated kinase (SGK) consists of three paralogs, SGK-1, SGK-2, and SGK-3, with SGK-1 being the better studied. Indeed, recognition of the role of SGK-1 in regulation of cell survival and proliferation has led to introduction of a number of small-molecule inhibitors for some types of cancer. In addition, SGK-1 regulates major physiologic effects, such as renal solute transport, and contributes to the pathogenesis of non-neoplastic conditions involving major organs including the heart and the kidney. These observations raise the prospect for therapeutic modulation of SGK-1 to reduce the burden of such diseases as myocardial infarction and acute kidney injury. Following a brief description of the structure and function of SGK family of proteins, the present review is primarily focused on our current understanding of the role of SGK-1 in pathologies related to ischemia-reperfusion injury involving several organs (e.g., heart, kidney). The essential role of the mitochondrial permeability transition pore in cell death coupled with the pro-survival function of SGK-1 raise the prospect that its therapeutic modulation could beneficially impact conditions associated with ischemia-reperfusion injury. SIGNIFICANCE STATEMENT: Since the discovery of serum glucocorticoid-regulated kinase (SGK)-1, extensive research has unraveled its role in cancer biology and, thus, its therapeutic targeting. Increasingly, it is also becoming clear that SGK-1 is a major determinant of the outcome of ischemia-reperfusion injury to various organs. Thus, evaluation of existing information should help identify gaps in our current knowledge and also determine whether and how its therapeutic modulation could impact the outcome of ischemia-reperfusion injury.

The role of glycolytic metabolic pathways in cardiovascular disease and potential therapeutic approaches

Cardiovascular disease (CVD) is a major threat to human health, accounting for 46% of non-communicable disease deaths. Glycolysis is a conserved and rigorous biological process that breaks down glucose into pyruvate, and its primary function is to provide the body with the energy and intermediate products needed for life activities. The non-glycolytic actions of enzymes associated with the glycolytic pathway have long been found to be associated with the development of CVD, typically exemplified by metabolic remodeling in heart failure, which is a condition in which the heart exhibits a rapid adaptive response to hypoxic and hypoxic conditions, occurring early in the course of heart failure. It is mainly characterized by a decrease in oxidative phosphorylation and a rise in the glycolytic pathway, and the rise in glycolysis is considered a hallmark of metabolic remodeling. In addition to this, the glycolytic metabolic pathway is the main source of energy for cardiomyocytes during ischemia-reperfusion. Not only that, the auxiliary pathways of glycolysis, such as the polyol pathway, hexosamine pathway, and pentose phosphate pathway, are also closely related to CVD. Therefore, targeting glycolysis is very attractive for therapeutic intervention in CVD. However, the relationship between glycolytic pathway and CVD is very complex, and some preclinical studies have confirmed that targeting glycolysis does have a certain degree of efficacy, but its specific role in the development of CVD has yet to be explored. This article aims to summarize the current knowledge regarding the glycolytic pathway and its key enzymes (including hexokinase (HK), phosphoglucose isomerase (PGI), phosphofructokinase-1 (PFK1), aldolase (Aldolase), phosphoglycerate metatase (PGAM), enolase (ENO) pyruvate kinase (PKM) lactate dehydrogenase (LDH)) for their role in cardiovascular diseases (e.g., heart failure, myocardial infarction, atherosclerosis) and possible emerging therapeutic targets.

The Signaling Mechanism of Remote Postconditioning of the Heart: Prospects of the Use of Remote Postconditioning for the Treatment of Acute Myocardial Infarction

Acute myocardial infarction (AMI) remains the leading cause of mortality in the world, highlighting an urgent need for the development of novel, more effective approaches for the treatment of AMI. Remote postconditioning (RPost) of the heart could be a useful approach. It was demonstrated that RPost triggers infarct size reduction, improves contractile function of the heart in reperfusion, mitigates apoptosis, and stimulates autophagy in animals with coronary artery occlusion and reperfusion. Endogenous opioid peptides and adenosine could be involved in RPost. It was found that kinases and NO-synthase participate in RPost. KATP channels, MPT pore, and STAT3 could be hypothetical end-effectors of RPost. Metabolic syndrome and old age abolish the cardioprotective effect of RPost in rats. The data on the efficacy of RPost in clinical practice are inconsistent. These data are discussed in the review.

A bibliometric analysis of myocardial ischemia/reperfusion injury from 2000 to 2023

Background

Myocardial ischemia/reperfusion injury (MIRI) refers to the more severe damage that occurs in the previously ischemic myocardium after a short-term interruption of myocardial blood supply followed by restoration of blood flow within a certain period of time. MIRI has become a major challenge affecting the therapeutic efficacy of cardiovascular surgery.

Methods

A scientific literature search on MIRI-related papers published from 2000 to 2023 in the Web of Science Core Collection database was conducted. VOSviewer was used for bibliometric analysis to understand the scientific development and research hotspots in this field.

Results

A total of 5,595 papers from 81 countries/regions, 3,840 research institutions, and 26,202 authors were included. China published the most papers, but the United States had the most significant influence. Harvard University was the leading research institution, and influential authors included Lefer David J., Hausenloy Derek J., Yellon Derek M., and others. All keywords can be divided into four different directions: risk factors, poor prognosis, mechanisms and cardioprotection.

Conclusion

Research on MIRI is flourishing. It is necessary to conduct an in-depth investigation of the interaction between different mechanisms and multi-target therapy will be the focus and hotspot of MIRI research in the future.