Dataset Information

CD137 signaling aggravates myocardial ischemia-reperfusion injury by inhibiting mitophagy mediated NLRP3 inflammasome activation.

ABSTRACT:

Background

The inflammatory response caused by the NLRP3 is closely related to the formation of myocardial ischemia-reperfusion injury. Costimulatory receptor CD137 and its ligand play a crucial role in regulating the inflammatory immune response in atherosclerosis, which is the fundamental cause of cardiovascular diseases. However, the roles of CD137 signaling in the process of myocardial ischaemia-reperfusion (IR) injury remain unknown.

Methods

Genetic ablation was used to determine the functional significance of CD137 in myocardial IR injury. Expression of CD137 was examined by Western-blot, quantitative real-time polymerase chain reaction, and immunohistochemistry in a murine IR model by coronary artery ligation. Even's blue-TTC staining and echocardiography to evaluate the severity of myocardial IR injury. Furthermore, HL-1 cardiomyocytes treated with agonist-CD137 recombinant protein were used to explore the underlying mechanism in CD137 signaling-induced NLRP3 inflammasome activation in response to hypoxia/reoxygenation or LPS/ATP.

Results

We demonstrated that CD137 knockout significantly improved cardiac function, accompanied by a markedly reduced NLRP3-mediated inflammatory response and IA/AAR which were reversed by mitophagy inhibitor Mdivi-1. Activating CD137 signaling significantly inhibited mitophagy and provoked NLRP3-mediated inflammatory response in H/R-injured or LPS-primed and ATP-stimulated HL-1 cardiomyocytes, the effects of which could be abolished by either anti-CD137 or mitophagy activator FCCP. Besides, mitochondrial ROS was augmented by activating CD137 signaling through the suppression of mitophagy.

Conclusions

Our results reveal that activating CD137 signaling aggravates myocardial IR injury by upregulating NLRP3 inflammasome activation via suppressing mitophagy and promoting mtROS generation.

SUBMITTER: Zang GY

PROVIDER: S-EPMC10114197 | biostudies-literature | 2023 Mar

REPOSITORIES: biostudies-literature

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Publications

CD137 signaling aggravates myocardial ischemia-reperfusion injury by inhibiting mitophagy mediated NLRP3 inflammasome activation.

Zang Guang-Yao GY Yin Qing Q Shao Chen C Sun Zhen Z Zhang Li-Li LL Xu Yao Y Li Li-Hua LH Wang Zhong-Qun ZQ

Journal of geriatric cardiology : JGC 20230301 3

<h4>Background</h4>The inflammatory response caused by the NLRP3 is closely related to the formation of myocardial ischemia-reperfusion injury. Costimulatory receptor CD137 and its ligand play a crucial role in regulating the inflammatory immune response in atherosclerosis, which is the fundamental cause of cardiovascular diseases. However, the roles of CD137 signaling in the process of myocardial ischaemia-reperfusion (IR) injury remain unknown.<h4>Methods</h4>Genetic ablation was used to deter ...[more]

PMID: 37091265

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Project description:BackgroundMyocardial ischemia-reperfusion injury (MIRI) is the most common cause of death worldwide. The NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome plays an important role in the inflammatory response to MIRI. Dexmedetomidine (DEX), a specific agonist of α2-adrenergic receptor, is commonly used for sedation and analgesia in anesthesia and critically ill patients. Several studies have shown that dexmedetomidine has a strong anti-inflammatory effect in many diseases. Here, we investigated whether dexmedetomidine protects against MIRI by inhibiting the activation of the NLRP3 inflammasome in vitro.MethodsWe established an MIRI model in cardiomyocytes (CMs) alone and in coculture with cardiac fibroblasts (CFs) by hypoxia/reoxygenation (H/R) in vitro. The cells were treated with dexmedetomidine with or without MCC950 (a potent selective NLRP3 inhibitor). The beating rate and cell viability of cardiomyocytes, NLRP3 localization, the expression of inflammatory cytokines and NLRP3 inflammasome-related proteins, and the expression of apoptosis-related proteins, including Bcl2 and BAX, were determined.ResultsDexmedetomidine treatment increased the beating rates and viability of cardiomyocytes cocultured with cardiac fibroblasts. The expression of the NLRP3 protein was significantly upregulated in cardiac fibroblasts but not in cardiomyocytes after H/R and was significantly attenuated by dexmedetomidine treatment. Expression of the inflammatory cytokines IL-1β, IL-18 and TNF-α was significantly increased in cardiac fibroblasts after H/R and was attenuated by dexmedetomidine treatment. NLRP3 inflammasome activation induced the increased expression of cleaved caspase1, mature IL-1β and IL-18, while dexmedetomidine suppressed H/R-induced NLRP3 inflammasome activation in cardiac fibroblasts. In addition, dexmedetomidine reduced the expression of Bcl2 and BAX in cocultured cardiomyocytes by suppressing H/R-induced NLRP3 inflammasome activation in cardiac fibroblasts.ConclusionDexmedetomidine treatment can suppress H/R-induced NLRP3 inflammasome activation in cardiac fibroblasts, thereby alleviating MIRI by inhibiting the inflammatory response.

Project description:Background and aimsDonors with fatty livers are considered to address the shortage of livers for transplantation, but those livers are particularly sensitive to ischemia-reperfusion injury (IRI), and an increased incidence of graft failure is observed. Kupffer cells account for 20-35% of liver nonparenchymal cells, and have been shown to participate in the process of IRI and inflammatory reactions of hepatic steatosis. NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) is an intracellular sensor activated by Kupffer cells to promote generation and participates in IRI. Dynamics-associated protein 1 (Drp1) is one of the main proteins regulating mitochondrial division and exacerbates IRI by affecting mitochondrial dynamics. The mechanism of interaction of Kupffer cells with Drp1 and NLRP3 to aggravate IRI has not been clarified.MethodsA mouse model of hepatic steatosis was established by feeding the mice with a high-fat diet. In vitro experiments were performed using AML12 normal mouse liver cells and RAW264.7 mononuclear macrophage cells cultured in medium with palmitate and oleic acid. Western blotting and immunohistochemical (IHC) staining were used to detect the expression of NLRPP3 and Drp1 in IRI in the control and high-fat diet groups. The expression of F4/80+ cells during IRI in hepatic steatosis was verified by IHC staining, and the role of NLRPP3 and Drp1 in Kupffer-cell mediated IRI was investigated by targeting Drp-1 inhibition.ResultsDrp1 and NLRP3 expression was increased during IRI in hepatic steatosis, and the expression of Drp1 and NLRP3 were decreased after the elimination of Kupffer cells. That indicated Kupffer cells were involved in the process of IRI in hepatic steatosis through the action of Drp1 and NLRP3. After Drp1 inhibition, liver function was restored and NLRP3 expression level was reduced.ConclusionsKupffer cells aggravated IRI in hepatic steatosis via NLRP3 and Drp1. Drp1 inhibitors might be useful as specific therapeutics to alleviate IRI in hepatic steatosis and may have promise in case of liver donor shortage.

Project description:Objective: Globally, cerebral ischemia has been shown to be the second leading cause of death. Our previous studies have shown that Taohong Siwu Decoction (THSWD) exhibits obvious neuroprotective effects on cerebral ischemia/reperfusion (I/R) injury (CIRI). In this study, we further explored the modulatory effect of THSWD on mitochondrial autophagy in CIRI and the relationship between modulatory effect and NLRP3 inflammatory vesicle activation, so as to further explain the mechanism of neuroprotective effect of THSWD. Methods: Middle cerebral artery occlusion reperfusion (MCAO/R) model in rats was built to simulate I/R. Adult male SD rats (220-270 g) were randomly divided into the following four groups: the sham group, the MCAO/R group, the MCAO/R + THSWD group, and the MCAO/R + THSWD + Mitochondrial division inhibitor 1 (Mdivi-1) group. Neurological defect scores were used to evaluate neurological function. 2,3,5-Triphenyltetrazolium chloride (TTC) staining was conducted to measure cerebral infarct volume. Nissl staining, H&E staining and TUNEL staining were executed to detect ischemic cortical neuronal cell viability and apoptosis. Electron microscopy was used to observe the ultrastructural changes of mitochondria. Total Reactive Oxygen Species (ROS) in tissue were measured by fluorescence spectrophotometry, and the activation status of microglia was evaluated by Iba-1/CD16 immunofluorescence staining. The levels of mitophagy-related proteins (LC3, Parkin, PINK1), NLRP3 inflammasome-related proteins (NLRP3, ASC, Pro-caspase-1, Cleaved-caspase-1), and inflammatory cytokines (Pro-IL-18, Pro-IL-1β, IL-18, IL-1β) were evaluated by western blotting. Results: The studies showed that THSWD treatment alleviated cerebral infarction and neurological deficiencies. THSWD upregulated the expressions of autophagy markers (LC3-II/LC3-I and Beclin1) mitochondrial autophagy markers (Parkin and PINK1) after CIRI. Furthermore, THSWD treatment attenuated microglia activation and damage to mitochondrial structures, thereby reducing ROS production and NLRP3 inflammasome activation. In contrast, the mitochondrial autophagy inhibitor Mdivi-1 inhibited the above beneficial effects of THSWD. Conclusions: THSWD exhibits neuroprotective effects against MCAO/R in rats by enhancing mitochondrial autophagy and reducing NLRP3 inflammasome activation.

Dataset Information

CD137 signaling aggravates myocardial ischemia-reperfusion injury by inhibiting mitophagy mediated NLRP3 inflammasome activation.

Background

Methods

Results

Conclusions

Publications

CD137 signaling aggravates myocardial ischemia-reperfusion injury by inhibiting mitophagy mediated NLRP3 inflammasome activation.

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