The role of RIP3 in cardiomyocyte necrosis induced by mitochondrial damage of myocardial ischemia-reperfusion

Novel, non-conventional pathways of necroptosis in the heart and other organs: Molecular mechanisms, regulation and inter-organelle interplay

Necroptosis, a cell death modality that is defined as a necrosis-like cell death depending on the receptor-interacting protein kinase 3 (RIPK3) and mixed lineage kinase domain-like pseudokinase (MLKL), has been found to underlie the injury of various organs. Nevertheless, the molecular background of this cell loss seems to also involve, at least under certain circumstances, some novel axes, such as RIPK3-PGAM5-Drp1 (mitochondrial protein phosphatase 5-dynamin-related protein 1), RIPK3-CaMKII (Ca2+/calmodulin-dependent protein kinase II) and RIPK3-JNK-BNIP3 (c-Jun N-terminal kinase-BCL2 Interacting Protein 3). In addition, endoplasmic reticulum stress and oxidative stress via the higher production of reactive oxygen species produced by the mitochondrial enzymes and the enzymes of the plasma membrane have been implicated in necroptosis, thereby depicting an inter-organelle interplay in the mechanisms of this cell death. However, the role and relationship between these novel non-conventional signalling and the well-accepted canonical pathway in terms of tissue- and/or disease-specific prioritisation is completely unknown. In this review, we provide current knowledge on some necroptotic pathways being not directly associated with RIPK3-MLKL execution and report studies showing the role of respective microRNAs in the regulation of necroptotic injury in the heart and in some other tissues having a high expression of the pro-necroptotic proteins.

Sex-Dependent Mechanisms of Cell Death Modalities in Cardiovascular Disease

Despite currently available therapies, cardiovascular diseases (CVD) are among the leading causes of death globally. Biological sex is a critical determinant of the occurrence, progression and overall outcome of CVD. However, the underlying mechanisms are incompletely understood. A hallmark of CVD is cell death. Based on the inability of the human heart to regenerate, loss of functional cardiac tissue can lead to irreversible detrimental effects. Here, we summarize current knowledge on how biological sex affects cell death-related mechanisms in CVD. Initially, we discuss apoptosis and necrosis, but we specifically focus on the relatively newly recognized programmed necrosis-like processes: pyroptosis and necroptosis. We also discuss the role of 17β-estradiol (E2) in these processes, particularly in terms of inhibiting pyroptotic and necroptotic signaling. We put forward that a better understanding of the effects of biological sex and E2 might lead to the identification of novel targets with therapeutic potential.

AMPK Activation Alleviates Myocardial Ischemia-Reperfusion Injury by Regulating Drp1-Mediated Mitochondrial Dynamics

Mitochondrial dysfunction is a salient feature of myocardial ischemia/reperfusion injury (MIRI), while the potential mechanism of mitochondrial dynamics disorder remains unclear. This study sought to explore whether activation of Adenosine monophosphate-activated protein kinase (AMPK) could alleviate MIRI by regulating GTPase dynamin-related protein 1 (Drp1)-mediated mitochondrial dynamics. Isolated mouse hearts in a Langendorff perfusion system were subjected to ischemia/reperfusion (I/R) treatment, and H9C2 cells were subjected to hypoxia /reoxygenation (H/R) treatment in vitro. The results showed that AICAR, the AMPK activator, could significantly improve the function of left ventricular, decrease arrhythmia incidence and myocardial infarction area of isolated hearts. Meanwhile, AICAR increased superoxide dismutase (SOD) activity and decreased malondialdehyde (MDA) content in myocardial homogenate. Mechanistically, AICAR inhibited the phosphorylation of Drp1 at Ser 616 while enhanced phosphorylation of Drp1 at Ser 637. In addition, AICAR reduced the expression of inflammatory cytokines including TNF-ɑ, IL-6, and IL-1β, as well as mitochondrial fission genes Mff and Fis1, while improved the expression of mitochondrial fusion genes Mfn1 and Mfn2. Similar results were also observed in H9C2 cells. AICAR improved mitochondrial membrane potential (MMP), reduced reactive oxygen species (ROS) production, and inhibited mitochondrial damage. To further prove if Drp1 regulated mitochondrial dynamics mediated AMPK protection effect, the mitochondrial fission inhibitor Mdivi-1 was utilized. We found that Mdivi-1 significantly improved MMP, inhibited ROS production, reduced the expression of TNF-a, IL-6, IL-1β, Fis1, and Mff, and improved the expression of Mfn1 and Mfn2. However, the protection effect of Mdivi-1 was not reversed by AMPK inhibitor Compound C. In conclusion, this study confirmed that activation of AMPK exerted the protective effects on MIRI, which were largely dependent on the inhibition of Drp1-mediated mitochondrial fission.

Plasma levels of receptor-interacting protein kinase 3 is associated with postoperative acute kidney injury in acute DeBakey type I aortic dissection

Background

Postoperative acute kidney injury (AKI) in acute DeBakey type I aortic dissection (ADIAD) is common but has unclear pathogeneses and limited treatments. Receptor-interacting protein kinase 3 (RIP3), a mediator of necroptosis, is associated with human sepsis-induced and posttraumatic AKI, but its role in human postoperative AKI in ADIAD remains unclear. We assumed that RIP3 levels is associated with postoperative AKI in ADIAD.

Methods

Plasma samples and the clinical data of continuous patients with ADIAD were collected prospectively. The patients were divided into three groups according to AKI stage postoperatively. The plasma RIP3 levels were compared among the groups, and the relationship between RIP3 and serum creatinine (sCr), inflammatory cytokines as well as clinical results were analyzed.

Results

Eighty patients were enrolled. The postoperative and elevated RIP3 levels among the three groups were significantly different (P < 0.0001), both with a positive trend across the AKI stage (P for trend < 0.001), and they were also independent risk factors for postoperative AKI in ADIAD (OR = 1.018 and 1.026, P < 0.05). The postoperative RIP3 levels were positively correlated with the aortic crossclamp time (R = 0.253, P < 0.05); the peak values of sCr, procalcitonin, interleukin-6 and lactate postoperatively; the mechanical ventilation time; and the ICU stay time (R = 0.66, 0.369, 0.409, 0.397, 0.474 and 0.435, respectively; all P < 0.001). Plasma RIP3 level and sCr were comparable in diagnosing postoperative AKI in ADIAD (P = 0.898), and higher postoperative RIP3 level was associated with lower survival rate.

Conclusion

The plasma RIP3 levels are associated with postoperative AKI, inflammatory response and clinical outcomes in ADIAD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-022-01783-0.

Interplay of Oxidative Stress and Necrosis-like Cell Death in Cardiac Ischemia/Reperfusion Injury: A Focus on Necroptosis

Extensive research work has been carried out to define the exact significance and contribution of regulated necrosis-like cell death program, such as necroptosis to cardiac ischemic injury. This cell damaging process plays a critical role in the pathomechanisms of myocardial infarction (MI) and post-infarction heart failure (HF). Accordingly, it has been documented that the modulation of key molecules of the canonical signaling pathway of necroptosis, involving receptor-interacting protein kinases (RIP1 and RIP3) as well as mixed lineage kinase domain-like pseudokinase (MLKL), elicit cardioprotective effects. This is evidenced by the reduction of the MI-induced infarct size, alleviation of myocardial dysfunction, and adverse cardiac remodeling. In addition to this molecular signaling of necroptosis, the non-canonical pathway, involving Ca2+/calmodulin-dependent protein kinase II (CaMKII)-mediated regulation of mitochondrial permeability transition pore (mPTP) opening, and phosphoglycerate mutase 5 (PGAM5)–dynamin-related protein 1 (Drp-1)-induced mitochondrial fission, has recently been linked to ischemic heart injury. Since MI and HF are characterized by an imbalance between reactive oxygen species production and degradation as well as the occurrence of necroptosis in the heart, it is likely that oxidative stress (OS) may be involved in the mechanisms of this cell death program for inducing cardiac damage. In this review, therefore, several observations from different studies are presented to support this paradigm linking cardiac OS, the canonical and non-canonical pathways of necroptosis, and ischemia-induced injury. It is concluded that a multiple therapeutic approach targeting some specific changes in OS and necroptosis may be beneficial in improving the treatment of ischemic heart disease.

Receptor Interacting Protein Kinases 1/3: The Potential Therapeutic Target for Cardiovascular Inflammatory Diseases

The receptor interacting protein kinases 1/3 (RIPK1/3) have emerged as the key mediators in cell death pathways and inflammatory signaling, whose ubiquitination, phosphorylation, and inhibition could regulate the necroptosis and apoptosis effectually. Recently, more and more studies show great interest in the mechanisms and the regulator of RIPK1/3-mediated inflammatory response and in the physiopathogenesis of cardiovascular diseases. The crosstalk of autophagy and necroptosis in cardiomyocyte death is a nonnegligible conversation of cell death. We elaborated on RIPK1/3-mediated necroptosis, pathways involved, the latest regulatory molecules and therapeutic targets in terms of ischemia reperfusion, myocardial remodeling, myocarditis, atherosclerosis, abdominal aortic aneurysm, and cardiovascular transplantation, etc.

Inhibition of Cardiac RIP3 Mitigates Early Reperfusion Injury and Calcium-Induced Mitochondrial Swelling without Altering Necroptotic Signalling

Receptor-interacting protein kinase 3 (RIP3) is a convergence point of multiple signalling pathways, including necroptosis, inflammation and oxidative stress; however, it is completely unknown whether it underlies acute myocardial ischemia/reperfusion (I/R) injury. Langendorff-perfused rat hearts subjected to 30 min ischemia followed by 10 min reperfusion exhibited compromised cardiac function which was not abrogated by pharmacological intervention of RIP3 inhibition. An immunoblotting analysis revealed that the detrimental effects of I/R were unlikely mediated by necroptotic cell death, since neither the canonical RIP3-MLKL pathway (mixed lineage kinase-like pseudokinase) nor the proposed non-canonical molecular axes involving CaMKIIδ-mPTP (calcium/calmodulin-dependent protein kinase IIδ-mitochondrial permeability transition pore), PGAM5-Drp1 (phosphoglycerate mutase 5-dynamin-related protein 1) and JNK-BNIP3 (c-Jun N-terminal kinase-BCL2-interacting protein 3) were activated. Similarly, we found no evidence of the involvement of NLRP3 inflammasome signalling (NOD-, LRR- and pyrin domain-containing protein 3) in such injury. RIP3 inhibition prevented the plasma membrane rupture and delayed mPTP opening which was associated with the modulation of xanthin oxidase (XO) and manganese superoxide dismutase (MnSOD). Taken together, this is the first study indicating that RIP3 regulates early reperfusion injury via oxidative stress- and mitochondrial activity-related effects, rather than cell loss due to necroptosis.

Drp1-dependent mitochondrial fission in cardiovascular disease

Mitochondria are highly dynamic organelles undergoing cycles of fusion and fission to modulate their morphology, distribution, and function, which are referred as 'mitochondrial dynamics'. Dynamin-related protein 1 (Drp1) is known as the major pro-fission protein whose activity is tightly regulated to clear the damaged mitochondria via mitophagy, ensuring a strict control over the intricate process of cellular and organ dynamics in heart. Various posttranslational modifications (PTMs) of Drp1 have been identified including phosphorylation, SUMOylation, palmitoylation, ubiquitination, S-nitrosylation, and O-GlcNAcylation, which implicate a role in the regulation of mitochondrial dynamics. An intact mitochondrial homeostasis is critical for heart to fuel contractile function and cardiomyocyte metabolism, while defects in mitochondrial dynamics constitute an essential part of the pathophysiology underlying various cardiovascular diseases (CVDs). In this review, we summarize current knowledge on the critical role of Drp1 in the pathogenesis of CVDs including endothelial dysfunction, smooth muscle remodeling, cardiac hypertrophy, pulmonary arterial hypertension, myocardial ischemia-reperfusion, and myocardial infarction. We also highlight how the targeting of Drp1 could potentially contribute to CVDs treatments.

Mitochondrial quality control mechanisms as molecular targets in cardiac ischemiareperfusion injury

Mitochondrial damage is a critical contributor to cardiac ischemia/reperfusion (I/R) injury. Mitochondrial quality control (MQC) mechanisms, a series of adaptive responses that preserve mitochondrial structure and function, ensure cardiomyocyte survival and cardiac function after I/R injury. MQC includes mitochondrial fission, mitochondrial fusion, mitophagy and mitochondria-dependent cell death. The interplay among these responses is linked to pathological changes such as redox imbalance, calcium overload, energy metabolism disorder, signal transduction arrest, the mitochondrial unfolded protein response and endoplasmic reticulum stress. Excessive mitochondrial fission is an early marker of mitochondrial damage and cardiomyocyte death. Reduced mitochondrial fusion has been observed in stressed cardiomyocytes and correlates with mitochondrial dysfunction and cardiac depression. Mitophagy allows autophagosomes to selectively degrade poorly structured mitochondria, thus maintaining mitochondrial network fitness. Nevertheless, abnormal mitophagy is maladaptive and has been linked to cell death. Although mitochondria serve as the fuel source of the heart by continuously producing adenosine triphosphate, they also stimulate cardiomyocyte death by inducing apoptosis or necroptosis in the reperfused myocardium. Therefore, defects in MQC may determine the fate of cardiomyocytes. In this review, we summarize the regulatory mechanisms and pathological effects of MQC in myocardial I/R injury, highlighting potential targets for the clinical management of reperfusion.

Remifentanil preconditioning protects against hypoxia-induced senescence and necroptosis in human cardiac myocytes in vitro

Remifentanil and other opioids are suggested to be protective against ischemia-reperfusion injury in animal models and coronary artery bypass surgery patients, however the molecular basis of such protection is far from being understood. In the present study, we have used a model of human cardiomyocytes treated with the hypoxia-mimetic agent cobalt chloride to investigate remifentanil preconditioning-based adaptive responses and underlying mechanisms. Hypoxic conditions promoted oxidative and nitrosative stress, p21-mediated cellular senescence and the activation of necroptotic pathway that was accompanied by a 2.2-, 9.6- and 8.2-fold increase in phosphorylation status of mixed lineage kinase domain-like pseudokinase (MLKL) and release of pro-inflammatory cytokine IL-8 and cardiac troponin I, a marker of myocardial damage, respectively. Remifentanil preconditioning was able to lower hypoxia-mediated protein carbonylation and limit MLKL-based signaling and pro-inflammatory response to almost normoxic control levels, and decrease hypoxia-induced pro-senescent activity of about 21% compared to control hypoxic conditions. In summary, we have shown for the first time that remifentanil can protect human cardiomyocytes against hypoxia-induced cellular senescence and necroptosis that may have importance with respect to the use of remifentanil to diminish myocardial ischemia and reperfusion injury in patients undergoing cardiac surgery.

Mitochondrial and mitochondrial-independent pathways of myocardial cell death during ischaemia and reperfusion injury

Acute myocardial infarction causes lethal injury to cardiomyocytes during both ischaemia and reperfusion (IR). It is important to define the precise mechanisms by which they die in order to develop strategies to protect the heart from IR injury. Necrosis is known to play a major role in myocardial IR injury. There is also evidence for significant myocardial death by other pathways such as apoptosis, although this has been challenged. Mitochondria play a central role in both of these pathways of cell death, as either a causal mechanism is the case of mitochondrial permeability transition leading to necrosis, or as part of the signalling pathway in mitochondrial cytochrome c release and apoptosis. Autophagy may impact this process by removing dysfunctional proteins or even entire mitochondria through a process called mitophagy. More recently, roles for other programmed mechanisms of cell death such as necroptosis and pyroptosis have been described, and inhibitors of these pathways have been shown to be cardioprotective. In this review, we discuss both mitochondrial and mitochondrial‐independent pathways of the major modes of cell death, their role in IR injury and their potential to be targeted as part of a cardioprotective strategy. This article is part of a special Issue entitled ‘Mitochondria as targets of acute cardioprotection’ and emerged as part of the discussions of the European Union (EU)‐CARDIOPROTECTION Cooperation in Science and Technology (COST) Action, CA16225.

Combination of the ginsenosides Rb3 and Rb2 exerts protective effects against myocardial ischemia reperfusion injury in rats

Ginsenoside Rb3 (G-Rb3) has been demonstrated to alleviate myocardial ischemia reperfusion injury (MIRI); however, it is difficult to separate G-Rb2 from its isomer G-Rb3. The current study aimed to compare the cardioprotective effects of G-Rb3 and the concomitant use of G-Rb3 and G-Rb2 (G-Rb3/Rb2) on MIRI in rats. A rat model of MIRI was established by ligation of the left anterior descending coronary artery and the rats were randomly divided into five groups. Prior to MIRI, G-Rb3/Rb2 (20 mg/kg), G-Rb3 (20 mg/kg) and diltiazem (DLZ; 20 mg/kg, as a positive control) were orally administered to the rats once a day for 3 consecutive days. After 30 min of ischemia and 120 min of reperfusion, cardiac function, infarct size, cardiac marker enzymes, antioxidative parameters, inflammatory factors, histopathological changes, cardiomyocyte apoptosis, and B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein and caspase-3 expression were determined using a multi-channel physiological recording system, nitrotetrazolium blue chloride, biochemical kits, radioimmunoassay kits, hematoxylin and eosin, terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling assay, immunohistochemistry and reverse transcription-quantitative PCR, respectively. The results indicated that treatment with G-Rb3/Rb2 significantly protected rats against MIRI, as shown by improved cardiac function, reduced myocardial ischemic area, decreased serum activities of aspartate aminotransferase, lactate dehydrogenase and creatine kinase MB, decreased serum concentrations of interleukin-6 and tumor necrosis factor-α, decreased malondialdehyde concentration in myocardial tissues, increased activities of superoxide dismutase, glutathione peroxidase and catalase in myocardial tissues, reduced histopathological changes in myocardial tissues, reduced number of apoptotic cardiomyocytes, and changes in the expression levels of caspase-3, Bcl-2 and Bax. In addition, the effects of treatment with G-Rb3/Rb2, G-Rb3 or DLZ were equivalent. The protective effects of G-Rb3/Rb2 on MIRI were similar to those of G-Rb3 in terms of oxidative stress, inflammatory factors and inhibition of cardiomyocyte apoptosis. Therefore, G-Rb3/Rb2 may be developed as a concomitant treatment for MIRI.

Guidelines for evaluating myocardial cell death

Cell death is a fundamental process in cardiac pathologies. Recent studies have revealed multiple forms of cell death, and several of them have been demonstrated to underlie adverse cardiac remodeling and heart failure. With the expansion in the area of myocardial cell death and increasing concerns over rigor and reproducibility, it is important and timely to set a guideline for the best practices of evaluating myocardial cell death. There are six major forms of regulated cell death observed in cardiac pathologies, namely apoptosis, necroptosis, mitochondrial-mediated necrosis, pyroptosis, ferroptosis, and autophagic cell death. In this article, we describe the best methods to identify, measure, and evaluate these modes of myocardial cell death. In addition, we discuss the limitations of currently practiced myocardial cell death mechanisms.

PD98059 protects the brain against mitochondrial-mediated apoptosis and autophagy in a cardiac arrest rat model

AIMS

Mitochondrial dysfunction has been regarded as one of the hallmarks of cerebral ischemia-reperfusion injury. In previous studies, we have provided evidence that the extracellular signaling pathway (ERK) 1/2 inhibitor PD98059 improved the neurological deficits by modulating antioxidant and anti-apoptotic activities in rats subjected to cardiac arrest/cardiopulmonary resuscitation (CA/CPR). Since oxidative stress can activate mitochondria-dependent apoptosis and autophagy, we further explored the effects of PD98059 on mitochondria involved with apoptosis and autophagy in rat CA model.

MATERIALS AND METHODS

We disposed PD98059 in CA/CPR rats, tested the mitochondrial-mediated apoptosis pathway in brain tissues at 24 h post-resuscitation by mitochondrial permeability transition pores (MPTP), cytochrome c (CytC), BCL-2, BAX, caspase-3, as well as autophagy by LC3, Beclin-1, and p62. Furthermore, we explored the relationship of dynamin-related protein 1 (Drp1) with apoptosis and autophagy.

KEY FINDINGS

Our study showed that PD98059 decreased the openings of MPTP, CytC release, caspase3 activation, apoptotic indices, LC3-II, Beclin-1and increased P62. PD98059 also inhibited mitochondria-dependent apoptosis and the activity of autophagy in a dose-dependent manner in rat cerebral cortices at 24 h post-resuscitation. The generation of phosphorylated Drp1-616 was down-regulated accompanied by a decrease of TUNEL-positive cells and LC3 in dual immunostaining after PD98059 inhibited activation of ERK signaling pathway in a dose-dependent manner in rat cerebral cortices at 24 h post-resuscitation.

SIGNIFICANCE

PD98059 protects the brain against mitochondrial-mediated apoptosis and autophagy at 24 h post-resuscitation in rats subjected to CA/CPR, which is linked with the downregulation of Drp1 expression.