RAMP1 Protects Hepatocytes against Ischemia-reperfusion Injury by Inhibiting the ERK/YAP Pathway
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ABSTRACT:
SUBMITTER: Tang Y
PROVIDER: S-EPMC11022058 | biostudies-literature | 2024 Feb
REPOSITORIES: biostudies-literature
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Project description:BackgroundIschemia-reperfusion injury (IRI) is a major challenge in liver transplantation. The mitochondrial pathway plays a pivotal role in hepatic IRI. Levosimendan, a calcium channel sensitizer, was shown to attenuate apoptosis after IRI in animal livers. The aim of this study was to investigate the effect of levosimendan on apoptosis in human hepatocytes.MethodsPrimary human hepatocytes were either exposed to hypoxia or cultured under normoxic conditions. After the hypoxic phase, reoxygenation was implemented and cells were treated with different concentrations of levosimendan (10ng/ml, 100ng/ml, 1000ng/ml). The overall metabolic activity of the cells was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and aspartate aminotransferase (AST) levels were determined in order to quantify hepatic injury. Fluorescence-activated cell sorting (FACS) analysis was applied to measure necrosis and apoptosis. Finally, Western blotting was performed to analyze apoptotic pathway proteins.ResultsAdministration of levosimendan during reperfusion increases the metabolic activity of human hepatocytes and decreases AST levels. Moreover, apoptosis after IRI is reduced in treated vs. untreated hepatocytes, and levosimendan prevents down-regulation of the anti-apoptotic protein Bcl-2 as well as up-regulation of the pro-apoptotic protein BAX.ConclusionThe present study suggests a protective effect of levosimendan on human hepatocytes. Our findings suggest that treatment with levosimendan during reperfusion attenuates apoptosis of human hepatocytes by influencing BAX and Bcl-2 levels.
| S-EPMC5690693 | biostudies-literature
Project description:BackgroundHepatic 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.MethodsHuman 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.ResultsAutophagy 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).ConclusionsYAP 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.
| S-EPMC10950187 | biostudies-literature
Project description:Ischemia/reperfusion (I/R) injury with severe cell death is a major complication involved in liver transplantation and resection. The identification of key regulators improving hepatocyte activity may provide potential strategies to clinically resolve I/R-induced injury. N6-methyladenosine (m6A) RNA modification is essential for tissue homeostasis and pathogenesis. However, the potential involvement of m6A in the regulation of hepatocyte activity and liver injury has not been fully explored. In the present study, we found that hepatocyte AlkB homolog H5 (ALKBH5) levels were decreased both in vivo and in vitro I/R models. Hepatocyte-specific ALKBH5 overexpression effectively attenuated I/R-induced liver necrosis and improved cell proliferation in mice. Mechanistically, ALKBH5-mediated m6A demethylation improved the mRNA stability of YTH N6-methyladenosine RNA-binding protein 1 (YTHDF1), thereby increasing its expression, which consequently promoted the translation of Yes-associated protein (YAP). In conclusion, ALKBH5 is a regulator of hepatic I/R injury that improves hepatocyte repair and proliferation by maintaining YTHDF1 stability and YAP content. The ALKBH5-m6A-YTHDF1-YAP axis represents promising therapeutic targets for hepatic I/R injury to improve the prognosis of liver surgery.
| S-EPMC11546256 | biostudies-literature
Project description:Myocardial ischemia-reperfusion (IR) injury occurs when occlusive coronary artery restores blood supply after events such as myocardial infarction, stroke, cardiac arrest and resuscitation, and organ transplantation. However, the mechanisms involved are poorly understood, and effective pharmacological interventions are still lacking. A previous study demonstrated that 25-hydroxycholesterol (25-HC) contributed to lipid metabolism and cholesterol metabolism as an oxysterol molecule. We herein explored whether 25-hydroxycholesterol (25-HC) has cardioprotective properties against IR injury and explored its underlying mechanisms. 25-HC was administered before reperfusion procedure in IR injury model mice. We found that 25-HC significantly reduced the IR-induced infarct size and improved cardiac function, and this protective effect was associated with reduced phosphorylation of p38-MAPK and JNK1/2. Besides, 25-HC also inhibited the Bax/Bcl-2 ratio and the relative expression of cleaved caspase-3. Furthermore, 25-HC decreased the PARP activity, indicating that 25-HC ameliorates IR injury via the PARP pathway. The 25-HC group abolished cardioprotection in the presence of little PARP activity, suggesting that the PARP activity is essential for 25-HC to exert its effect during IR injury. Our primary study indicates that 25-HC ameliorated IR injury by inhibiting the PARP activity and decreasing myocardial apoptosis, which makes it a potential therapeutic drug in IR injury of the heart.
| S-EPMC6949155 | biostudies-literature
Project description:Pyroptosis serves a crucial function in various types of ischemia and reperfusion injuries. Oridonin, a tetracycline diterpene derived from Rabdosia rubescens, can significantly inhibit the aggregation of NLRP3-mediated inflammasome. This experiment is aimed at investigating the effect of oridonin on pyroptosis in mice cardiomyocytes. Based on the models of myocardial ischemia/reperfusion (I/R) and hypoxia/reoxygenation (H/R), Evans Blue/TTC double staining, TUNEL staining, and Western blotting were applied to determine the effects of oridonin on myocardial damage, cellular activity and signaling pathways involved in pyroptosis. During I/R and H/R treatments, the extent of gasdermin D-N domains was upregulated in cardiomyocytes. Apart from that, oridonin improved cell survival in vitro and decreased the myocardial infarct size in vivo by also downregulating the activation of pyroptosis. Finally, the expression levels of ASC, NLRP3 and p-p65 were markedly upregulated in cardiomyocytes after H/R treatment, whereas oridonin suppressed the expression of these proteins. The present experiment revealed that myocardial I/R injury and pyroptosis can be alleviated and inhibited by oridonin pretreatment via NF-κB/NLRP3 signaling pathway, both in vivo and in vitro. Therefore, oridonin may serve as a potentially novel agent for the clinical treatment of myocardial ischemia-reperfusion injuries.
| S-EPMC9690185 | biostudies-literature
Project description:Oxidative stress-induced cell death plays a major role in the progression of ischemic acute renal failure. Using microarrays, we sought to identify a stress-induced gene that may be a therapeutic candidate. Human proximal tubule (HK2) cells were treated with hydrogen peroxide (H2O2) and RNA was applied to an Affymetrix gene chip. Five genes were markedly induced in a parallel time-dependent manner by cluster analysis, including activating transcription factor 3 (ATF3), p21(WAF1/CiP1) (p21), CHOP/GADD153, dual-specificity protein phosphatase, and heme oxygenase-1. H2O2 rapidly induced ATF3 approximately 12-fold in HK2 cells and approximately 6.5-fold in a mouse model of renal ischemia-reperfusion injury. Adenovirus-mediated expression of ATF3 protected HK2 cells against H2O2-induced cell death, and this was associated with a decrease of p53 mRNA and an increase of p21 mRNA. Moreover, when ATF3 was overexpressed in mice via adenovirus-mediated gene transfer, ischemia-reperfusion injury was reduced. In conclusion, ATF3 plays a protective role in renal ischemia-reperfusion injury and the mechanism of the protection may involve suppression of p53 and induction of p21.
| S-EPMC2396738 | biostudies-literature
Project description:Primary cardiac myocytes isolated from neonatal Wistar rats were cultured and simulated ischemia/reperfusion injury were conducted on them in the presence or absence of decorin. Decorin is a small leucin-rich proteoglycan, which has a cardiocytoprotective effect. The underlaying mechanism of this cardiocytoprotective phenomenon is unknown, therefore our aim was to investigate the changes in the mRNA expression between the decorin (3nM) treated and vehicle-treated control cells.
2020-12-31 | E-MTAB-9325 | biostudies-arrayexpress
Project description:OBJECTIVE:To investigate the protective effect of melatonin against myocardial ischemia reperfusion (IR) injury in isolated rat hearts and explore the underlying mechanisms. METHODS:The isolated hearts from 40 male SD rats were randomly divided into 4 groups (n=10): the control group, where the hearts were perfused with KH solution for 175 min; IR group, where the hearts were subjected to global ischemia for 45 min followed by reperfusion for 120 min; IR+melatonin (Mel+IR) group, where melatonin (5 ?mol/L) was administered to the hearts 1 min before ischemia and during the first 5 min of reperfusion, followed by 115 min of reperfusion; and IR+2, 3-butanedione monoxime (IR+BDM) group, where the hearts were treated with BDM (20 mmol/L) in the same manner as melatonin treatment. Myocardial injury in the isolated hearts was assessed based on myocardial injury area, caspase-3 activity, and expressions of cytochrome C and cleaved caspase-3 proteins. Cardiac contracture was assessed using HE staining and by detecting lactate dehydrogenase (LDH) activity and the content of cardiac troponin I (cTnI) in the coronary outflow, measurement of left ventricular end-diastolic pressure (LVEDP) and electron microscopy. The content of ATP in the cardiac tissue was also determined. RESULTS:Compared with those in the control group, the isolated hearts in IR group showed significantly larger myocardial injury area and higher caspase-3 activity and the protein expressions of cytochrome C and cleaved caspase-3 with significantly increased LDH activity and cTnI content in the coronary outflow and elevated LVEDP at the end of reperfusion; HE staining showed obvious fractures of the myocardial fibers and the content of ATP was significantly decreased in the cardiac tissue; electron microscopy revealed the development of contraction bands. In the isolated hearts with IR, treatment with Mel or BDM significantly reduced the myocardial injury area, caspase-3 activity, and protein expressions of cytochrome C and cleaved caspase-3, obviously inhibited LDH activity, lowered the content of cTnI and LVEDP, reduced myocardial fiber fracture, and increased ATP content in the cardiac tissue. Both Mel and BDM inhibited the formation of contraction bands in the isolated hearts with IR injury. CONCLUSIONS:Mel can alleviate myocardial IR injury in isolated rat hearts by inhibiting cardiac contracture, the mechanism of which may involve the upregulation of ATP in the cardiac myocytes to lessen the tear of membrane and reduce cell content leakage.
| S-EPMC7386215 | biostudies-literature
Project description:BackgroundEffective strategies are dramatically needed to prevent and improve the recovery from myocardial ischemia and reperfusion (I/R) injury. Direct interactions between the mitochondria and endoplasmic reticulum (ER) during heart diseases have been recently investigated. This study was designed to explore the cardioprotective effects of gypenoside XVII (GP-17) against I/R injury. The roles of ER stress, mitochondrial injury, and their crosstalk within I/R injury and in GP-17-induced cardioprotection are also explored.MethodsCardiac contractility function was recorded in Langendorff-perfused rat hearts. The effects of GP-17 on mitochondrial function including mitochondrial permeability transition pore opening, reactive oxygen species production, and respiratory function were determined using fluorescence detection kits on mitochondria isolated from the rat hearts. H9c2 cardiomyocytes were used to explore the effects of GP-17 on hypoxia/reoxygenation.ResultsWe found that GP-17 inhibits myocardial apoptosis, reduces cardiac dysfunction, and improves contractile recovery in rat hearts. Our results also demonstrate that apoptosis induced by I/R is predominantly mediated by ER stress and associated with mitochondrial injury. Moreover, the cardioprotective effects of GP-17 are controlled by the PI3K/AKT and P38 signaling pathways.ConclusionGP-17 inhibits I/R-induced mitochondrial injury by delaying the onset of ER stress through the PI3K/AKT and P38 signaling pathways.
| S-EPMC8569261 | biostudies-literature
Project description:Renal ischemia/reperfusion (I/R) can induce acute kidney injury. Empagliflozin is a newly developed inhibitor of sodium-glucose cotransporter-2 (SGLT2) approved as an antidiabetic medication for patients with type 2 diabetes mellitus. Despite the established cardioprotective functions of empagliflozin, its protective role in renal I/R is unclear. Here, the present study evaluated the renoprotective effects of empagliflozin in a mouse model of renal I/R injury. Male C57/BL6 mice were allocated to sham-operated, I/R, and empagliflozin groups. Kidney pedicles on both sides were clamped for 45 min and were reperfused for 24 h. Empagliflozin (1 mg/kg) was administered to the mice for 2 days preischemia. The GSK-3β inhibitor SB216763 was administered intravenously at the beginning of reperfusion (0.1 mg/kg). Renal function and histological scores were evaluated. The kidneys were taken for immunohistochemical analysis, western blotting and apoptosis measurements. We found that empagliflozin decreased serum levels of creatinine and urea, reduced the average kidney weight-to-tibia length ratio, attenuated tubular damage, reduced renal proinflammatory cytokine expression and inhibited apoptosis in injured kidneys. Furthermore, empagliflozin increased renal glycogen synthase kinase 3β (GSK-3β) phosphorylation post I/R. Pharmacological inhibition of GSK-3β activity mimicked the renal protective effects offered by empagliflozin. In summary, these results support a protective role of empagliflozin against renal I/R injury.
| S-EPMC9652474 | biostudies-literature