Cardioprotective effect of MLN4924 on ameliorating autophagic flux impairment in myocardial ischemia-reperfusion injury by Sirt1

Cardioprotective effect of Cinnamamide derivative compound 10 against myocardial ischemia-reperfusion through regulating cardiac autophagy via Sirt1

BACKGROUND AND PURPOSE

Our previous research discovered that cinnamamide derivatives are a new type of potential cardioprotective agents myocardial ischemia-reperfusion (MIR) injury, among which Compound 10 exhibits wonderful beneficial action in vitro. However, the exact mechanism of Compound 10 still needs to be elucidated.

EXPERIMENTAL APPROACH

The protective effect of Compound 10 was determined by detecting the cell viability and LDH leakage rate in H9c2 cells subjected to H2O2. Alterations of electrocardiogram, echocardiography, cardiac infarct area, histopathology and serum myocardial zymogram were tested in MIR rats. Additionally, the potential mechanism of Compound 10 was explored through PCR. Network pharmacology and Western blotting was conducted to monitor levels of proteins related to autophagic flux and mTOR, autophagy regulatory substrate, induced by Compound 10 both in vitro and in vivo, as well as expressions of Sirtuins family members.

KEY RESULTS

Compound 10 significantly ameliorated myocardial injury, as demonstrated by increased cell viability, decreased LDH leakage in vitro, and declined serum myocardial zymogram, ST elevation, cardiac infarct area and improved cardiac function and microstructure of heart tissue in vivo. Importantly, Compound 10 markedly enhanced the obstruction of autophagic flux and inhibited excessive autophagy initiation against MIR by decreased ATG5, Rab7 and increased P-mTOR and LAMP2. Furthermore, Sirt1 knockdown hindered Compound 10's regulation on mTOR, leading to interrupted cardiac autophagic flux.

CONCLUSIONS AND IMPLICATIONS

Compound 10 exerted cardioprotective effects on MIR by reducing excessive autophagy and improving autophgic flux blockage. Our work would take a novel insight in seeking effective prevention and treatment strategies against MIR injury.

The NEDD8 activating enzyme inhibitor MLN4924 mitigates doxorubicin-induced cardiotoxicity in mice

Doxorubicin (DOX) is a widely utilized chemotherapeutic agent in clinical oncology for treating various cancers. However, its clinical use is constrained by its significant side effects. Among these, the development of cardiomyopathy, characterized by cardiac remodeling and eventual heart failure, stands as a major concern following DOX chemotherapy. In our current investigation, we have showcased the efficacy of MLN4924 in mitigating doxorubicin-induced cardiotoxicity through direct inhibition of the NEDD8-activating enzyme, NAE. MLN4924 demonstrated the ability to stabilize mitochondrial function post-doxorubicin treatment, diminish cardiomyocyte apoptosis, alleviate oxidative stress-induced damage in the myocardium, enhance cardiac contractile function, mitigate cardiac fibrosis, and impede cardiac remodeling associated with heart failure. At the mechanistic level, MLN4924 intervened in the neddylation process by inhibiting the NEDD8 activating enzyme, NAE, within the murine cardiac tissue subsequent to doxorubicin treatment. This intervention resulted in the suppression of NEDD8 protein expression, reduction in neddylation activity, and consequential manifestation of cardioprotective effects. Collectively, our findings posit MLN4924 as a potential therapeutic avenue for mitigating doxorubicin-induced cardiotoxicity by attenuating heightened neddylation activity through NAE inhibition, thereby offering a viable and promising treatment modality for afflicted patients.

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.

N-n-butyl haloperidol iodide mitigates myocardial ischemia/reperfusion injury through activation of SIRT1-Nrf2 signaling loop

ABSTRACT

N-n-butyl haloperidol iodide (F2), a derivative of haloperidol developed by our group, exhibits potent antioxidative properties and confers protection against cardiac ischemia/reperfusion (I/R) injury. The protective mechanisms by which F2 ameliorates I/R injury remain obscure. The activation of nuclear factor erythroid 2-related factor 2 (Nrf2), a key transcription factor transactivating many antioxidative genes, also attenuates I/R-induced myocardial damage. The present study investigated whether the cardioprotective effect of F2 depends on Nrf2 using a mouse heart I/R model. F2 (0.1, 0.2 or 0.4 mg/kg) or vehicle was intravenously injected to mice 5 min before reperfusion. Systemic administration of 0.4 mg/kg F2 led to a significant reduction in I/R injury, which was accompanied by enhanced activation of Nrf2 signaling. The cardioprotection conferred by F2 was largely abrogated in Nrf2-deficient mice. Importantly, we found F2-induced activation of Nrf2 is SIRT1-dependent, as pharmacologically inhibiting SIRT1 by the specific inhibitor EX527 blocked Nrf2 activation. Moreover, F2-upregulated expression of SIRT1 was also Nrf2-dependent, as Nrf2 deficiency inhibited SIRT1 upregulation. These results indicate that SIRT1-Nrf2 signaling loop activation is indispensable for the protective effect of F2 against myocardial I/R injury, and may provide new insights for the treatment of ischemic heart disease.

ncRNAs Orchestrate Chemosensitivity Induction by Neddylation Blockades

We performed an integrative transcriptomic in silico analysis using lung adenocarcinoma A549 cells treated with the neddylation inhibitor MLN4924 and the gefitinib-resistant PC9 cell line (PC9GR). We focused on the transcriptional effects of the top differentially expressed ncRNA biotypes and their correlating stemness factors. Interestingly, MLN4924-treated cells showed a significant upregulation of mRNAs involved in carcinogenesis, cell attachment, and differentiation pathways, as well as a parallel downregulation of stemness maintenance and survival signaling pathways, an effect that was inversely observed in PC9GR cells. Moreover, we found that stemness factor expression could be contrasted by selected up-regulated ncRNAs upon MLN4924 treatment in a dose and time-independent manner. Furthermore, upregulated miRNAs and lncRNA-targeted mRNAs showed an evident enrichment of proliferation, differentiation, and apoptosis pathways, while downregulated ncRNA-targeted mRNAs were implicated in stem cell maintenance. Finally, our results proved that stemness (KLF4 and FGFR2) and epithelial-mesenchymal transition (ZEB2, TWIST2, SNAI2, CDH2, and VIM) factors, which are highly expressed in PC9GR cells compared to gefitinib-sensitive PC9 cells, could be abrogated with the neddylation inhibitor MLN4924 mainly through activation of epithelial differentiation pathways, thus exerting a protective role in lung cancer cells and chemosensitivity against lung tumorigenic transformation.

High-density lipoprotein regulates angiogenesis by affecting autophagy via miRNA-181a-5p

We previously demonstrated that normal high-density lipoprotein (nHDL) can promote angiogenesis, whereas HDL from patients with coronary artery disease (dHDL) is dysfunctional and impairs angiogenesis. Autophagy plays a critical role in angiogenesis, and HDL regulates autophagy. However, it is unclear whether nHDL and dHDL regulate angiogenesis by affecting autophagy. Endothelial cells (ECs) were treated with nHDL and dHDL with or without an autophagy inhibitor. Autophagy, endothelial nitric oxide synthase (eNOS) expression, miRNA expression, nitric oxide (NO) production, superoxide anion (O2•-) generation, EC migration, and tube formation were evaluated. nHDL suppressed the expression of miR-181a-5p, which promotes autophagy and the expression of eNOS, resulting in NO production and the inhibition of O2•- generation, and ultimately increasing in EC migration and tube formation. dHDL showed opposite effects compared to nHDL and ultimately inhibited EC migration and tube formation. We found that autophagy-related protein 5 (ATG5) was a direct target of miR-181a-5p. ATG5 silencing or miR-181a-5p mimic inhibited nHDL-induced autophagy, eNOS expression, NO production, EC migration, tube formation, and enhanced O2•- generation, whereas overexpression of ATG5 or miR-181a-5p inhibitor reversed the above effects of dHDL. ATG5 expression and angiogenesis were decreased in the ischemic lower limbs of hypercholesterolemic low-density lipoprotein receptor null (LDLr-/-) mice when compared to C57BL/6 mice. ATG5 overexpression improved angiogenesis in ischemic hypercholesterolemic LDLr-/- mice. Taken together, nHDL was able to stimulate autophagy by suppressing miR-181a-5p, subsequently increasing eNOS expression, which generated NO and promoted angiogenesis. In contrast, dHDL inhibited angiogenesis, at least partially, by increasing miR-181a-5p expression, which decreased autophagy and eNOS expression, resulting in a decrease in NO production and an increase in O2•- generation. Our findings reveal a novel mechanism by which HDL affects angiogenesis by regulating autophagy and provide a therapeutic target for dHDL-impaired angiogenesis.

SIRT1 is a regulator of autophagy: Implications for the progression and treatment of myocardial ischemia-reperfusion

SIRT1 is a highly conserved nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylase. It is involved in the regulation of various pathophysiological processes, including cell proliferation, survival, differentiation, autophagy, and oxidative stress. Therapeutic activation of SIRT1 protects the heart and cardiomyocytes from pathology-related stress, particularly myocardial ischemia/reperfusion (I/R). Autophagy is an important metabolic pathway for cell survival during energy or nutrient deficiency, hypoxia, or oxidative stress. Autophagy is a double-edged sword in myocardial I/R injury. The activation of autophagy during the ischemic phase removes excess metabolic waste and helps ensure cardiomyocyte survival, whereas excessive autophagy during reperfusion depletes the cellular components and leads to autophagic cell death. Increasing research on I/R injury has indicated that SIRT1 is involved in the process of autophagy and regulates myocardial I/R. SIRT1 regulates autophagy through various pathways, such as the deacetylation of FOXOs, ATGs, and LC3. Recent studies have confirmed that SIRT1-mediated autophagy plays different roles at different stages of myocardial I/R injury. By targeting the mechanism of SIRT1-mediated autophagy at different stages of I/R injury, new small-molecule drugs, miRNA activators, or blockers can be developed. For example, resveratrol, sevoflurane, quercetin, and melatonin in the ischemic stage, coptisine, curcumin, berberine, and some miRNAs during reperfusion, were involved in regulating the SIRT1-autophagy axis, exerting a cardioprotective effect. Here, we summarize the possible mechanisms of autophagy regulation by SIRT1 in myocardial I/R injury and the related molecular drug applications to identify strategies for treating myocardial I/R injury.

Dexmedetomidine combined with propofol attenuates myocardial ischemia/reperfusion injury by activating the AMPK signaling pathway

Objective

Myocardial ischemia/reperfusion (MI/R) injury is a major cause of cardiac tissue damage, with high disability and death rates. Although both dexmedetomidine (Dex) and propofol (PPF) have been indicated to alleviate MI/R injury in rat models, the effects of the combined use of these two drugs remain unclear. This study aimed to investigate the combined effects of Dex and PPF against MI/R injury and related mechanisms.

Methods

A rat model of MI/R injury was established and used to explore the combined effects of Dex and PPF on MI/R injury. Hematoxylin-eosin (HE) and Masson staining were used for histopathological evaluation. 2,3,5-triphenyltetrazolium chloride (TTC), echocardiography, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining were used to determine myocardial infarction size, cardiac function, and apoptosis, respectively. Enzyme-linked immunosorbent assay (ELISA) was performed to assess myocardial function and oxidative stress (OS). Autophagy was observed through transmission electron microscopy. Moreover, western blotting was conducted to detect autophagy markers and the AMPK pathway.

Results

The combination of Dex and PPF alleviated histopathological injury, reduced myocardial infarction, and rescued cardiac dysfunction in MI/R rats. Furthermore, Dex combined with PPF decreased the levels of MDA and ROS and increased the SOD level in MI/R rats. Besides, Dex combined with PPF inhibited myocardial apoptosis in MI/R rats. After combined treatment with Dex and PPF, the number of autophagosomes, expression levels of Beclin-1 and LC3II/LC3I were elevated, while the expression levels of p62 were reduced in MI/R rats. The combined use of Dex and PPF activated the AMPK pathway in MI/R rats. Compound C (an AMPK inhibitor) could abolish the combined effects of Dex and PPF on alleviating myocardial injury and enhancing autophagy in MI/R rats.

Conclusion

The combination of Dex and PPF attenuated MI/R injury in rats, which may be associated with the activation of the AMPK signaling pathway.

Treponema pallidum membrane protein Tp47 induced autophagy and inhibited cell migration in HMC3 cells via the PI3K/AKT/FOXO1 pathway

The migratory ability of microglia facilitates their rapid transport to a site of injury to kill and remove pathogens. However, the effect of Treponema pallidum membrane proteins on microglia migration remains unclear. The effect of Tp47 on the migration ability and autophagy and related mechanisms were investigated using the human microglial clone 3 cell line. Tp47 inhibited microglia migration, the expression of autophagy-associated protein P62 decreased, the expression of Beclin-1 and LC3-II/LC3-I increased, and the autophagic flux increased in this process. Furthermore, autophagy was significantly inhibited, and microglial cell migration was significantly increased after neutralisation with an anti-Tp47 antibody. In addition, Tp47 significantly inhibited the expression of p-PI3K, p-AKT, and p-mTOR proteins, and the sequential activation of steps in the PI3K/AKT/mTOR pathways effectively prevented Tp47-induced autophagy. Moreover, Tp47 significantly inhibited the expression of p-FOXO1 protein and promoted FOXO1 nuclear translocation. Inhibition of FOXO1 effectively suppressed Tp47-induced activation of autophagy and inhibition of migration. Treponema pallidum membrane protein Tp47-induced autophagy and inhibited cell migration in HMC3 Cells via the PI3K/AKT/FOXO1 pathway. These data will contribute to understanding the mechanism by which T. pallidum escapes immune killing and clearance after invasion into the central nervous system.

Dexmedetomidine Preconditioning Attenuates Myocardial Ischemia/Reperfusion Injury in Rats by Suppressing Mitophagy Via Activating Α2-Adrenergic Receptor

BACKGROUND

Dexmedetomidine (DEX), a specific α2-adrenergic receptor agonist, is protective against myocardial ischemia/reperfusion injury (MIRI). However, the association between DEX preconditioning-induced cardioprotection and mitophagy suppression remains unclear.

OBJECTIVE

Hence, we aimed to investigate whether DEX preconditioning alleviates MIRI by suppressing mitophagy via α2-adrenergic receptor activation.

METHOD

Sixty isolated rat hearts were treated with or without DEX before inducing ischemia and reperfusion; an α2-adrenergic receptor antagonist, yohimbine (YOH), was also administered before ischemia, alone or with DEX. The heart rate (HR), left ventricular diastolic pressure (LVDP), left ventricular end-diastolic pressure (LVEDP), maximal and minimal rate of left ventricular pressure development (±dp/dtmax), and myocardial infarction size were measured. The mitochondrial ultrastructure and autophagosomes were assessed using transmission electron microscopy. Mitochondrial membrane potential and reactive oxygen species (ROS) levels were measured using JC-1 and dichloride hydrofluorescein diacetate assays, respectively. The expression levels of the mitophagy-associated proteins Beclin1, LC3II/I ratio, p62, PINK1, and Parkin were detected by western blotting.

RESULTS

Compared with the control group, in the ischemia/reperfusion group, the HR, LVDP, and ±dp/dtmax were remarkably decreased (p< 0.05), whereas LVEDP and infarct sizes were significantly increased (p< 0.05). DEX preconditioning significantly improved cardiac dysfunction reduced myocardial infarction size, maintained mitochondrial structural integrity, increased mitochondrial membrane potential, inhibited autophagosomes formation, and decreased ROS production and Beclin1, LC3II/I ratio, PINK1, Parkin, and p62 expression(p< 0.05). When DEX and YOH were combined, YOH canceled the effect of DEX, whereas the use of YOH alone had no effect.

CONCLUSION

Therefore, DEX preconditioning was cardioprotective against MIRI in rats by suppressing mitophagy via α2-adrenergic receptor activation.

The Current State of Research on Sirtuin-Mediated Autophagy in Cardiovascular Diseases

Sirtuins belong to the class III histone deacetylases and possess nicotinamide adenine dinucleotide-dependent deacetylase activity. They are involved in the regulation of multiple signaling pathways implicated in cardiovascular diseases. Autophagy is a crucial adaptive cellular response to stress stimuli. Mounting evidence suggests a strong correlation between Sirtuins and autophagy, potentially involving cross-regulation and crosstalk. Sirtuin-mediated autophagy plays a crucial regulatory role in some cardiovascular diseases, including atherosclerosis, ischemia/reperfusion injury, hypertension, heart failure, diabetic cardiomyopathy, and drug-induced myocardial damage. In this context, we summarize the research advancements pertaining to various Sirtuins involved in autophagy and the molecular mechanisms regulating autophagy. We also elucidate the biological function of Sirtuins across diverse cardiovascular diseases and further discuss the development of novel drugs that regulate Sirtuin-mediated autophagy.

The CREG1-FBXO27-LAMP2 axis alleviates diabetic cardiomyopathy by promoting autophagy in cardiomyocytes

Autophagy plays an important role in the development of diabetic cardiomyopathy. Cellular repressor of E1A-stimulated genes 1 (CREG1) is an important myocardial protective factor. The aim of this study was to investigate the effects and mechanisms of CREG1 in diabetic cardiomyopathy. Male C57BL/6 J mice, Creg1 transgenic mice and cardiac-specific knockout mice were used to establish a type 2 diabetes model. Small animal ultrasound, Masson's staining and western blotting were used to evaluate cardiac function, myocardial fibrosis and autophagy. Neonatal mouse cardiomyocytes (NMCMs) were stimulated with palmitate, and the effects of CREG1 on NMCMs autophagy were examined. CREG1 deficiency exacerbated cardiac dysfunction, cardiac hypertrophy and fibrosis in mice with diabetic cardiomyopathy, which was accompanied by exacerbated autophagy dysfunction. CREG1 overexpression improved cardiac function and ameliorated cardiac hypertrophy and fibrosis in diabetic cardiomyopathy by improving autophagy. CREG1 protein expression was decreased in palmitate-induced NMCMs. CREG1 knockdown exacerbated cardiomyocyte hypertrophy and inhibited autophagy. CREG1 overexpression inhibited cardiomyocyte hypertrophy and improved autophagy. LAMP2 overexpression reversed the effect of CREG1 knockdown on palmitate-induced inhibition of cardiomyocyte autophagy. CREG1 inhibited LAMP2 protein degradation by inhibiting the protein expression of F-box protein 27 (FBXO27). Our findings indicate new roles of CREG1 in the development of diabetic cardiomyopathy.

Targeting NEDD8-activating enzyme for cancer therapy: developments, clinical trials, challenges and future research directions

NEDDylation, a post-translational modification through three-step enzymatic cascades, plays crucial roles in the regulation of diverse biological processes. NEDD8-activating enzyme (NAE) as the only activation enzyme in the NEDDylation modification has become an attractive target to develop anticancer drugs. To date, numerous inhibitors or agonists targeting NAE have been developed. Among them, covalent NAE inhibitors such as MLN4924 and TAS4464 currently entered into clinical trials for cancer therapy, particularly for hematological tumors. This review explains the relationships between NEDDylation and cancers, structural characteristics of NAE and multistep mechanisms of NEDD8 activation by NAE. In addition, the potential approaches to discover NAE inhibitors and detailed pharmacological mechanisms of NAE inhibitors in the clinical stage are explored in depth. Importantly, we reasonably investigate the challenges of NAE inhibitors for cancer therapy and possible development directions of NAE-targeting drugs in the future.

Lysine crotonylation of SERCA2a correlates to cardiac dysfunction and arrhythmia in Sirt1 cardiac-specific knockout mice

Protein post-translational modifications (PTMs) are important regulators of protein functions and produce proteome complexity. SIRT1 has NAD+-dependent deacylation of acyl-lysine residues. The present study aimed to explore the correlation between lysine crotonylation (Kcr) on cardiac function and rhythm in Sirt1 cardiac-specific knockout (ScKO) mice and related mechanism. Quantitative proteomics and bioinformatics analysis of Kcr were performed in the heart tissue of ScKO mice established with a tamoxifen-inducible Cre-loxP system. The expression and enzyme activity of crotonylated protein were assessed by western blot, co-immunoprecipitation, and cell biology experiment. Echocardiography and electrophysiology were performed to investigate the influence of decrotonylation on cardiac function and rhythm in ScKO mice. The Kcr of SERCA2a was significantly increased on Lys120 (1.973 folds). The activity of SERCA2a decreased due to lower binding energy of crotonylated SERCA2a and ATP. Changes in expression of PPAR-related proteins suggest abnormal energy metabolism in the heart. ScKO mice had cardiac hypertrophy, impaired cardiac function, and abnormal ultrastructure and electrophysiological activities. We conclude that knockout of SIRT1 alters the ultrastructure of cardiac myocytes, induces cardiac hypertrophy and dysfunction, causes arrhythmia, and changes energy metabolism by regulating Kcr of SERCA2a. These findings provide new insight into the role of PTMs in heart diseases.

Maternal obesity and offspring health: Adapting metabolic changes through autophagy and mitophagy

Maternal obesity leads to obstetric complications and a high prevalence of metabolic anomalies in the offspring. Among various contributing factors for maternal obesity-evoked health sequelae, developmental programming is considered as one of the leading culprit factors for maternal obesity-associated chronic comorbidities. Although a unified theory is still lacking to systematically address multiple unfavorable postnatal health sequelae, a cadre of etiological machineries have been put forward, including lipotoxicity, inflammation, oxidative stress, autophagy/mitophagy defect, and cell death. Hereinto, autophagy and mitophagy play an essential housekeeping role in the clearance of long-lived, damaged, and unnecessary cell components to maintain and restore cellular homeostasis. Defective autophagy/mitophagy has been reported in maternal obesity and negatively impacts fetal development and postnatal health. This review will provide an update on metabolic disorders in fetal development and postnatal health issues evoked by maternal obesity and/or intrauterine overnutrition and discuss the possible contribution of autophagy/mitophagy in metabolic diseases. Moreover, relevant mechanisms and potential therapeutic strategies will be discussed in an effort to target autophagy/mitophagy and metabolic disturbances in maternal obesity.

Neocryptotanshinone protects against myocardial ischemia-reperfusion injury by promoting autolysosome degradation of protein aggregates via the ERK1/2-Nrf2-LAMP2 pathway

BACKGROUND

Aggrephagy is a critical compensatory mechanism for the elimination of misfolded proteins resulting from stress and depends on the autolysosome degradation of protein aggregates. However, there have been few mechanism research related to aggrephagy in myocardial ischemia/reperfusion (I/R) injury. Neocryptotanshinone (NCTS) is a fat-soluble active compound extracted from Salvia miltiorrhiza, and may be cardioprotective against I/R. However, the efficacy and specific mechanism of NCTS on I/R have not been studied.

PURPOSE

The current study aimed to investigate the molecular mechanism of NCTS involved in the therapeutic effect on I/R, with a special emphasis on the up-regulation of the ERK1/2-Nrf2-LAMP2 pathway to increase autolysosomal degradation during aggrephagy.

METHODS

A rat model of myocardial I/R injury was constructed by left anterior descending (LAD) ligation-reperfusion. To verify cardiac protection, autolysosome clearance of protein aggregates, and their intracellular biological mechanism, an oxygen-glucose deprivation/recovery (OGD/R)-induced H9c2 cardiomyocyte model was created.

RESULTS

NCTS was found to have a significant cardioprotective effect in I/R rats as evidenced by remarkably improved pathological anatomy, decreased myocardial damage indicators, and substantially enhanced cardiac performance. Mechanistically, NCTS might boost the levels of LAMP2 mRNA and protein, total and Ser40 phosphorylated Nrf2, and ^{Thr202/Tyr204}p-ERK1/2 protein. Simultaneously, the cytoplasmic Nrf2 level was reduced after NCTS administration, which was contrary to the total Nrf2 content. However, these beneficial changes were reversed by the co-administration with ERK1/2 inhibitor, PD98059. NCTS therapy up-regulated Rab7 protein content, Cathepsin B activity, and lysosomal acidity, while down-regulating autophagosome numbers, Ubiquitin (Ub), and autophagosome marker protein accumulations through the above signaling pathway. This might indicate that NCTS enhanced lysosomal fusion and hydrolytic capacity. It was also found that NCTS intervention limited oxidative stress and cellular apoptosis both in vivo and in vitro.

CONCLUSIONS

We reported for the first time that NCTS promoted the autolysosome removal of protein aggregation both in vivo and in vitro, to exert the therapeutic advantages of myocardial I/R injury. This was reliant on the up-regulation of the ERK1/2-Nrf2-LAMP2 signaling pathway.

Targeting NEDDylation is a Novel Strategy to Attenuate Cisplatin-induced Nephrotoxicity

Although cisplatin remains a backbone of standard-of-care chemotherapy regimens for a variety of malignancies, its use is often associated with severe dose-limiting toxicities (DLT). Notably, 30%-40% of patients treated with cisplatin-based regimens are forced to discontinue treatment after experiencing nephrotoxicity as a DLT. New approaches that simultaneously prevent renal toxicity while improving therapeutic response have the potential to make a major clinical impact for patients with multiple forms of cancer. Here, we report that pevonedistat (MLN4924), a first-in-class NEDDylation inhibitor, alleviates nephrotoxicity and synergistically enhances the efficacy of cisplatin in head and neck squamous cell carcinoma (HNSCC) models. We demonstrate that pevonedistat protects normal kidney cells from injury while enhancing the anticancer activity of cisplatin through a thioredoxin-interacting protein (TXNIP)-mediated mechanism. Cotreatment with pevonedistat and cisplatin yielded dramatic HNSCC tumor regression and long-term animal survival in 100% of treated mice. Importantly, the combination decreased nephrotoxicity induced by cisplatin monotherapy as evidenced by the blockade of kidney injury molecule-1 (KIM-1) and TXNIP expression, a reduction in collapsed glomeruli and necrotic cast formation, and inhibition of cisplatin-mediated animal weight loss. Inhibition of NEDDylation represents a novel strategy to prevent cisplatin-induced nephrotoxicity while simultaneously enhancing its anticancer activity through a redox-mediated mechanism.

Significance

Cisplatin therapy is associated with significant nephrotoxicity, which limits its clinical use. Here we demonstrate that NEDDylation inhibition with pevonedistat is a novel approach to selectively prevent cisplatin-induced oxidative damage to the kidneys while simultaneously enhancing its anticancer efficacy. Clinical evaluation of the combination of pevonedistat and cisplatin is warranted.

NEDD8-conjugating enzyme E2s: critical targets for cancer therapy

NEDD8-conjugating enzymes, E2s, include the well-studied ubiquitin-conjugating enzyme E2 M (UBE2M) and the poorly characterized ubiquitin-conjugating enzyme E2 F (UBE2F). UBE2M and UBE2F have distinct and prominent roles in catalyzing the neddylation of Cullin or non-Cullin substrates. These enzymes are overexpressed in various malignancies, conferring a worse overall survival. Targeting UBE2M to influence tumor growth by either modulating several biological responses of tumor cells (such as DNA-damage response, apoptosis, or senescence) or regulating the anti-tumor immunity holds strong therapeutic potential. Multiple inhibitors that target the interaction between UBE2M and defective cullin neddylation protein 1 (DCN1), a co-E3 for neddylation, exhibit promising anti-tumor effects. By contrast, the potential benefits of targeting UBE2F are still to be explored. It is currently reported to inhibit apoptosis and then induce cell growth; hence, targeting UBE2F serves as an effective chemo-/radiosensitizing strategy by triggering apoptosis. This review highlights the most recent advances in the roles of UBE2M and UBE2F in tumor progression, indicating these E2s as two promising anti-tumor targets.

Experimental diabetes exacerbates autophagic flux impairment during myocardial I/R injury through calpain-mediated cleavage of Atg5/LAMP2

To explore the role of autophagic flux in the increased susceptibility of the experimental diabetic heart to ischaemia-reperfusion (I/R) injury, we established STZ-induced diabetic mice and performed I/R. In vitro, neonatal mouse cardiomyocytes were subjected to high glucose and hypoxia/reoxygenation challenge to mimic diabetic I/R injury. We found that experimental diabetes aggravated I/R-induced injury than compared with nondiabetic mice. Autophagic flux was impaired in I/R hearts, and the impairment was exacerbated in diabetic mice subjected to I/R with defective autophagosome formation and clearance. Calpains, calcium-dependent thiol proteases, were upregulated and highly activated after I/R of diabetes, while calpain inhibition attenuated cardiac function and cell death and partially restored autophagic flux. The expression levels of Atg5 and LAMP2, two crucial autophagy-related proteins, were significantly degraded in diabetic I/R hearts, alterations that were associated with calpain activation and could be reversed by calpain inhibition. Co-overexpression of Atg5 and LAMP2 reduced myocardial injury and normalized autophagic flux. In conclusion, experimental diabetes exacerbates autophagic flux impairment of cardiomyocytes under I/R stress, resulting in worse I/R-induced injury. Calpain activation and cleavage of Atg5 and LAMP2 at least partially account for the deterioration of autophagic flux impairment.

Neutrophil extracellular traps-triggered impaired autophagic flux via METTL3 underlies sepsis-associated acute lung injury

Neutrophil extracellular traps (NETs) assist pathogen clearance, while excessive NETs formation is associated with exacerbated inflammatory responses and tissue injury in acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Autophagy is generally considered to be a protective process, but autophagy dysfunction is harmful. Whether and how NETs affect autophagic flux during sepsis-induced ALI are currently unknown. Here, we confirmed that the level of NETs was increased in ARDS patients and mice models, which led to impairment of autophagic flux and deterioration of the disease. Mechanistically, NETs activated METTL3 mediated m⁶A methylation of Sirt1 mRNA in alveolar epithelial cells, resulting in abnormal autophagy. These findings provide new insights into how NETs contribute to the development of sepsis-associated ALI/ARDS.

Geniposide suppresses NLRP3 inflammasome-mediated pyroptosis via the AMPK signaling pathway to mitigate myocardial ischemia/reperfusion injury

BACKGROUND

NLRP3 inflammasome activation and pyroptosis play a significant role in myocardial ischemia reperfusion injury (MI/RI). Geniposide was reported to show potential therapeutic use for MI/RI with its anti-inflammatory and anti-oxidative properties. However, research on the specific mechanism of geniposide has not been reported.

METHODS

The MIRI model of animal was created in male C57BL/6J mice and the hypoxia reoxygenation (H/R) model was established for the in vitro experiments. Neonatal rat ventricular myocytes (NRVMs) and H9c2 cells with knockdown of TXNIP or NLRP3 were used. Geniposide was administered to mice before vascular ligation. HE staining, 2,3,5-triphenyltetrazolium chloride (TTC) staining, echocardiography, oxidative stress and myocardial enzyme detection were used to evaluate the cardioprotective effect of geniposide. Meanwhile, pharmacological approaches of agonist and inhibitor were used to observe potential pathway for geniposide cardioprotective in vitro and in vivo. Moreover, ELISA kits were adopted to detect the levels of inflammatory factors, such as IL-1β and IL-18. The gene and protein expression of NLRP3 and pyroptosis-related factors in heart tissue were performed by RT-PCR, western blotting and immunofluorescence in vivo and in vitro, respectively.

RESULTS

Our results indicate that geniposide can reduce the area of myocardial infarction, improve heart function, and inhibit the inflammatory response in mice after MI/RI. In addition, RT-PCR and western blotting shown geniposide promoting AMPK phosphorylation to activate myocardium energy metabolism and reducing the levels of genes and proteins expression of NLRP3, ASC, N-GSDMD and cleaved caspase-1, IL-1β, IL-18. Meanwhile, geniposide improved NRVMs energy metabolism, which decreased ROS levels and the protein expression of TXNIP and thus suppressed the expression of NLRP3. AMPK antagonist or agonist and siRNA downregulation of TXNIP or NLRP3 were also verify the effect of geniposide against H/R injury. Further research found that geniposide promoted the translocation of TXNIP and reduce the binding of TXNIP and NLRP3.

CONCLUSIONS

In our study, geniposide can significantly inhibit NLRP3 inflammasome activation via the AMPK signaling pathway and inhibit pyroptosis of cardiomyocytes in myocardial tissues.

Signaling Pathways Involved in Myocardial Ischemia-Reperfusion Injury and Cardioprotection: A Systematic Review of Transcriptomic Studies in Sus scrofa

Myocardial damage in acute myocardial infarctions (AMI) is primarily the result of ischemia−reperfusion injury (IRI). Recognizing the timing of transcriptional events and their modulation by cardioprotective strategies is critical to address the pathophysiology of myocardial IRI. Despite the relevance of pigs for translational studies of AMI, only a few have identified how transcriptomic changes shape cellular signaling pathways in response to injury. We systematically reviewed transcriptomic studies of myocardial IRI and cardioprotection in Sus scrofa. Gene expression datasets were analyzed for significantly enriched terms using the Enrichr analysis tool, and statistically significant results (adjusted p-values of <0.05) for Signaling Pathways, Transcription Factors, Molecular Functions, and Biological Processes were compared between eligible studies to describe how these dynamic changes transform the myocardium from an injured and inflamed tissue into a scar. Then, we address how cardioprotective interventions distinctly modulate the myocardial transcriptome and discuss the implications of uncovering gene regulatory networks for cardiovascular pathologies and translational applications.

Disruption of polycystin-1 cleavage leads to cardiac metabolic rewiring in mice

Cardiovascular manifestations account for marked morbi-mortality in autosomal dominant polycystic kidney disease (ADPKD). Pkd1- and Pkd2-deficient mice develop cardiac dysfunction, however the underlying mechanisms remain largely unclear. It is unknown whether impairment of polycystin-1 cleavage at the G-protein-coupled receptor proteolysis site, a significant ADPKD mutational mechanism, is involved in this process. We analyzed the impact of polycystin-1 cleavage on heart metabolism using Pkd1^V/V mice, a model unable to cleave this protein and with early cardiac dysfunction. Pkd1^V/V hearts showed lower levels of glucose and amino acids and higher lipid levels than wild-types, as well as downregulation of p-AMPK, p-ACCβ, CPT1B-Cpt1b, Ppara, Nppa and Acta1. These findings suggested decreased fatty acid β-oxidation, which was confirmed by lower oxygen consumption by Pkd1^V/V isolated mitochondria using palmitoyl-CoA. Pkd1^V/V hearts also presented increased oxygen consumption in response to glucose, suggesting that alternative substrates may be used to generate energy. Pkd1^V/V hearts displayed a higher density of decreased-size mitochondria, a finding associated with lower MFN1, Parkin and BNIP3 expression. These derangements were correlated with increased apoptosis and inflammation but not hypertrophy. Notably, Pkd1^V/V neonate cardiomyocytes also displayed shifts in oxygen consumption and p-AMPK downregulation, suggesting that, at least partially, the metabolic alterations are not induced by kidney dysfunction. Our findings reveal that disruption of polycystin-1 cleavage leads to cardiac metabolic rewiring in mice, expanding the understanding of heart dysfunction associated with Pkd1 deficiency and likely with human ADPKD.