Cellular FADD-like IL-1β-converting enzyme-inhibitory protein attenuates myocardial ischemia/reperfusion injury via suppressing apoptosis and autophagy simultaneously

Leveraging a neutrophil-derived PCD signature to predict and stratify patients with acute myocardial infarction: from AI prediction to biological interpretation

BACKGROUND

Programmed cell death (PCD) has recently been implicated in modulating the removal of neutrophils recruited in acute myocardial infarction (AMI). Nonetheless, the clinical significance and biological mechanism of neutrophil-related PCD remain unexplored.

METHODS

We employed an integrative machine learning-based computational framework to generate a predictive neutrophil-derived PCD signature (NPCDS) within five independent microarray cohorts from the peripheral blood of AMI patients. Non-negative matrix factorization was leveraged to develop an NPCDS-based AMI subtype. To elucidate the biological mechanism underlying NPCDS, we implemented single-cell transcriptomics on Cd45+ cells isolated from the murine heart of experimental AMI. We finally conducted a Mendelian randomization (MR) study and molecular docking to investigate the therapeutic value of NPCDS on AMI.

RESULTS

We reported the robust and superior performance of NPCDS in AMI prediction, which contributed to an optimal combination of random forest and stepwise regression fitted on nine neutrophil-related PCD genes (MDM2, PTK2B, MYH9, IVNS1ABP, MAPK14, GNS, MYD88, TLR2, CFLAR). Two divergent NPCDS-based subtypes of AMI were revealed, in which subtype 1 was characterized as inflammation-activated with more vibrant neutrophil activities, whereas subtype 2 demonstrated the opposite. Mechanically, we unveiled the expression dynamics of NPCDS to regulate neutrophil transformation from a pro-inflammatory phase to an anti-inflammatory phase in AMI. We uncovered a significant causal association between genetic predisposition towards MDM2 expression and the risk of AMI. We also found that lidoflazine, isotetrandrine, and cepharanthine could stably target MDM2.

CONCLUSION

Altogether, NPCDS offers significant implications for prediction, stratification, and therapeutic management for AMI.

cFLIPL alleviates myocardial ischemia-reperfusion injury by regulating pyroptosis

Alleviating myocardial ischemia-reperfusion injury (MIRI) plays a critical role in the prognosis and improvement of cardiac function following acute myocardial infarction. Pyroptosis is a newly identified form of cell death that has been implicated in the regulation of MIRI. In our study, H9c2 cells and SD rats were transfected using a recombinant adenovirus vector carrying cFLIPL , and the transfection was conducted for 3 days. Subsequently, H9c2 cells were subjected to 4 h of hypoxia followed by 12 h of reoxygenation to simulate an in vitro ischemia-reperfusion model. SD rats underwent 30 min of ischemia followed by 2 h of reperfusion to establish an MIRI model. Our findings revealed a notable decrease in cFLIPL expression in response to ischemia/reperfusion (I/R) and hypoxia/reoxygenation (H/R) injuries. Overexpression of cFLIPL can inhibit pyroptosis, reducing myocardial infarction area in vivo, and enhancing H9c2 cell viability in vitro. I/R and H/R injuries induced the upregulation of ASC, cleaved Caspase 1, NLRP3, GSDMD-N, IL-1β, and IL-18 proteins, promoting cell apoptosis. Our research indicates that cFLIPL may suppress pyroptosis by strategically binding with Caspase 1, inhibiting the release of inflammatory cytokines and preventing cell membrane rupture. Therefore, cFLIPL could potentially serve as a promising target for alleviating MIRI by suppressing the pyroptotic pathway.

Apoptotic cell death in disease-Current understanding of the NCCD 2023

Apoptosis is a form of regulated cell death (RCD) that involves proteases of the caspase family. Pharmacological and genetic strategies that experimentally inhibit or delay apoptosis in mammalian systems have elucidated the key contribution of this process not only to (post-)embryonic development and adult tissue homeostasis, but also to the etiology of multiple human disorders. Consistent with this notion, while defects in the molecular machinery for apoptotic cell death impair organismal development and promote oncogenesis, the unwarranted activation of apoptosis promotes cell loss and tissue damage in the context of various neurological, cardiovascular, renal, hepatic, infectious, neoplastic and inflammatory conditions. Here, the Nomenclature Committee on Cell Death (NCCD) gathered to critically summarize an abundant pre-clinical literature mechanistically linking the core apoptotic apparatus to organismal homeostasis in the context of disease.

cFLIPL Alleviates Myocardial Ischemia-Reperfusion Injury by Inhibiting Endoplasmic Reticulum Stress

PURPOSE

Endoplasmic reticulum stress (ERS) plays a crucial role in myocardial ischemia-reperfusion injury (MIRI). Cellular FLICE-inhibitory protein (cFLIP) is an essential regulator of apoptosis and plays a major role in regulating ERS. The present study aimed to investigate the effects of long isoform cFLIP (cFLIP_L) on endogenous apoptosis and the mechanism of ERS in MIRI.

METHODS

The cFLIP_L recombinant adenovirus vector was used to infect H9c2 cells and Sprague-Dawley (SD) rats. After infection for 72 h, ischemia was induced for 30 min, and reperfusion was then performed for 2 h to establish the MIRI model in SD rats. H9c2 cells were hypoxic for 4 h and then reoxygenated for 12 h to simulate ischemia/reperfusion (I/R) injury. Model parameters were evaluated by assessing cardiomyocyte viability, cell death (apoptosis), and ERS-related protein expression. In addition, tunicamycin (TM), an ERS agonist, was also added to the medium for pretreatment. Coimmunoprecipitation (Co-IP) of cFLIP_L and p38 MAPK protein was performed.

RESULTS

cFLIP_L expression was decreased in I/R injury and hypoxia/reoxygenation (H/R) injury, and cFLIP_L overexpression reduced myocardial infarction in vivo and increased the viability of H9c2 cells in vitro. I/R and H/R upregulated the protein expression of GRP78, IRE-1, and PERK to induce ERS and apoptosis. Interestingly, overexpression of cFLIP_L significantly inhibited ERS and subsequent apoptosis, which was reversed by an agonist of ERS. Moreover, Co-IP showed that cFLIP_L attenuated ERS and was associated with inhibiting the activation of p38 protein.

CONCLUSION

The expression of cFLIP_L is significantly downregulated in MIRI, and it is accompanied by excessive ERS and apoptosis. Upregulated cFLIP_L suppresses ERS to reduce myocardial apoptosis, which is associated with inhibiting the activity of p38 MAPK. Therefore, cFLIP_L may be a potential intervention target for MIRI.

Liraglutide Attenuates Myocardial Ischemia/Reperfusion Injury Through the Inhibition of Necroptosis by Activating GLP-1R/PI3K/Akt Pathway

Necroptosis is a crucial programmed cell death that is tightly associated with myocardial ischemia/reperfusion injury (MI/RI). Liraglutide is an effective option for the treatment of type 2 diabetes and has recently been reported to exert cardioprotective effects on MI/RI. Researchers do not know whether the cardioprotective effect of liraglutide is involved in regulating necroptosis. This study aimed to explore the effect of liraglutide on MI/RI-induced necroptosis and its potential mechanisms. Hypoxia/reoxygenation (H/R) was performed on H9c2 cells in vitro to simulate ischemia/reperfusion (I/R) injury, and an MI/RI rat model was established in vivo by ligating the anterior descending branch of the left coronary artery. H/R or I/R damage was assessed by performing biochemical assay, Hoechst 33342/PI staining, H&E (hematoxylin and eosin) staining, and Annexin-V/PI staining. Our data revealed that liraglutide resulted in markedly increased cell viability and reduced cardiac enzyme release by protecting cardiomyocytes from a necrosis-like phenotype after H/R. The myocardial infarct size and cardiac enzyme release were reduced in the heart tissues from the liraglutide-treated group. The levels of necroptosis-associated proteins (receptor-interacting protein kinase 3 (RIPK3), p-RIPK3, and phosphorylated-mixed lineage kinase domain-like protein (p-MLKL)) were also reduced by the liraglutide treatment. Mechanistically, we revealed that liraglutide exerted cardioprotective effects through a glucagon-like peptide-1 receptor (GLP-1R) and phosphatidylinositol-3 kinase (PI3K)-dependent pathway. Both the GLP-1R inhibitor exendin (9-39) and the PI3K inhibitor LY294002 abrogated the protective effects of liraglutide in vitro. We found that liraglutide may attenuate MI/RI by inhibiting necroptosis, in part by enhancing the activity of the GLP-1R/PI3K/Akt pathway.

The crosstalk among autophagy, apoptosis, and pyroptosis in cardiovascular disease

In recent years, the mechanism of cell death has become a hotspot in research on the pathogenesis and treatment of cardiovascular disease (CVD). Different cell death modes, including autophagy, apoptosis, and pyroptosis, are mosaic with each other and collaboratively regulate the process of CVD. This review summarizes the interaction and crosstalk of key pathways or proteins which play a critical role in the entire process of CVD and explores the specific mechanisms. Furthermore, this paper assesses the interrelationships among these three cell deaths and reviews how they regulate the pathogenesis of CVD. By understanding how these three cell death modes go together we can learn about the pathogenesis of CVD, which will enable us to identify new targets for preventing, controlling, and treating CVD. It will not only reduce mortality but also improve the quality of life.

Maslinic Acid Inhibits Myocardial Ischemia-Reperfusion Injury-Induced Apoptosis and Necroptosis via Promoting Autophagic Flux

Apoptosis, necroptosis, and autophagy are the major programmed cell death in myocardial ischemia-reperfusion injury (MIRI). Maslinic acid (MA) has been found to regulate pathophysiological processes that mediate programmed cell death in MIRI, such as inflammation and oxidative stress. However, its effects on MIRI remain unclear. This study intends to explore the role of MA in MIRI. In vitro, MA had no obvious cytotoxic effects on H9C2 cells, and significantly improved the impaired cell viability caused by hypoxia reoxygenation (HR). In vivo, MA significantly alleviated ischemia reperfusion (IR)-induced left ventricular myocardial tissue injury, downregulated creatine kinase-myocardial band (CK-MB), and lactate dehydrogenase (LDH) levels in serum as well as reducing infarct size. Moreover, MA inhibited HR-induced mitochondrial apoptosis and necroptosis in vitro and in vivo. Of interest, MA interacts with lysosome-associated membrane protein 2 (LAMP2). MA protected LAMP2 from IR and promoting autophagic flux to inhibit apoptosis and necroptosis, whereas these effects were reversed by co-treatment with lysosomal inhibitor BarfA1. In conclusion, MA can inhibit MIRI-induced apoptosis and necroptosis by promoting autophagic flux. These results support that MA is a potential agent to ameliorate MIRI.

Propofol Upregulates MicroRNA-30b to Inhibit Excessive Autophagy and Apoptosis and Attenuates Ischemia/Reperfusion Injury In Vitro and in Patients

Evidence reveals that propofol protects cells via suppressing excessive autophagy induced by hypoxia/reoxygenation (H/R). Previously, we found in a genome-wide microRNA profile analysis that several autophagy-related microRNAs were significantly altered during the process of H/R in the presence or absence of propofol posthypoxia treatment (P-PostH), but how these microRNAs work in P-PostH is still largely unknown. Here, we found that one of these microRNAs, microRNA-30b (miR-30b), in human umbilical vein endothelial cells (HUVECs) was downregulated by H/R treatment but significantly upregulated by 100 M propofol after H/R treatment. miR-30b showed similar changes in open heart surgery patients. By dual-luciferase assay, we found that Beclin-1 is the direct target of miR-30b. This conclusion was also supported by knockdown or overexpression of miR-30b. Further studies showed that miR-30b inhibited H/R-induced autophagy activation. Overexpression or knockdown of miR-30b regulated autophagy-related protein gene expression in vitro. To clarify the specific role of propofol in the inhibition of autophagy and distinguish the induction of autophagy from the damage of autophagy flux, we used bafilomycin A1. LC3-II levels were decreased in the group treated with propofol combined with bafilomycin A1 compared with the group treated with bafilomycin A1 alone after hypoxia and reoxygenation. Moreover, HUVECs transfected with Ad-mCherry-GFP-LC3b confirmed the inhibitory effect of miR-30b on autophagy flux. Finally, we found that miR-30b is able to increase the cellular viability under the H/R condition, partially mimicking the protective effect of propofol which suppressed autophagy via enhancing miR-30b and targeting Beclin-1. Therefore, we concluded that propofol upregulates miR-30b to repress excessive autophagy via targeting Beclin-1 under H/R condition. Thus, our results revealed a novel mechanism of the protective role of propofol during anesthesia. Clinical Trial Registration Number. This trial is registered with ChiCTR-IPR-14005470. The name of the trial register: Propofol Upregulates MicroRNA-30b to Repress Beclin-1 and Inhibits Excessive Autophagy and Apoptosis.

Epigallocatechin-3-gallate protects cardiomyocytes from hypoxia-reoxygenation damage via raising autophagy related 4C expression

Myocardial ischemia/reperfusion (I/R) injury is a serious issue during the therapy of myocardial infarction. Herein, we explored the beneficial influence of Epigallocatechin-3-gallate (EGCG) on hypoxia/reoxygenation (H/R)-stimulated cardiomyocyte H9c2 cells damage, along with possible internal molecular mechanism related autophagy related 4C (ATG4C). H9c2 cells were subjected to H/R stimulation and/or EGCG treatment. ATG4C mRNA expression was measured via q-PCR assay. ATG4C overexpression plasmid (OE-ATG4C) was transfected to arise ATG4C level. Cell viability, apoptosis, reactive oxygen species (ROS) production, ATP level were tested via CCK-8 assay, Annexin V-FITC/PI staining, DCFH-DA staining and ATP Assay Kit, respectively. Western blotting was performed to test Cleaved-caspase 3, Cleaved-caspase 9, cytochrome C, and LC3B protein levels. H/R stimulation resulted in H9c2 cell viability loss, promoted cell apoptosis, and ROS overproduction, as well as lowered ATP level in cells. EGCG treatment alleviated H/R-resulted H9c2 cell viability loss, cell apoptosis, ROS overproduction, and reduction of ATP level. Moreover, H/R stimulation reduced the ATG4C expression in H9c2 cells, while EGCG raised the ATG4C expression. Overexpression of ATG4C strengthened the beneficial influence of EGCG on H/R-stimulated H9c2 cell viability, apoptosis and ROS production. Besides, ATG4C overexpression weakened the H/R-stimulated H9c2 cell autophagy via reducing LC3B II/I expression. EGCG exerted beneficial influence on H/R-stimulated cardiomyocytes, which protected cardiomyocytes from H/R-stimulated viability loss, apoptosis, and ROS overproduction via enhancing ATG4C expression.