DADLE improves hepatic ischemia/reperfusion injury in mice via activation of the Nrf2/HO‑1 pathway

[D-Ala2, D-Leu5]-enkephalin (DADLE) provides protection against myocardial ischemia reperfusion injury by inhibiting Wnt/β-Catenin pathway

BACKGROUND

Acute myocardial infarction is one of the leading causes of death worldwide. Myocardial ischemia reperfusion (MI/R) injury occurs immediately after the coronary reperfusion and aggravates myocardial ischemia. Whether the Wnt/β-Catenin pathway is involved in the protection against MI/R injury by DADLE has not been evaluated. Therefore, the present study aimed to investigate the protective effect of DADLE against MI/R injury in a mouse model and to further explore the association between DADLE and the Wnt/β-Catenin pathway.

METHODS

Forty-four mice were randomly allocated to four groups: Group Control (PBS Control), Group D 0.25 (DADLE 0.25 mg/kg), Group D 0.5 (DADLE 0.5 mg/kg), and Group Sham. In the control and DADLE groups, myocardial ischemia injury was induced by occluding the left anterior descending coronary artery (LAD) for 45 min. PBS and DADLE were administrated, respectively, 5 min before reperfusion. The sham group did not go through LAD occlusion. 24 h after reperfusion, functions of the left ventricle were assessed through echocardiography. Myocardial injury was evaluated using TTC double-staining and HE staining. Levels of myocardial enzymes, including CK-MB and LDH, in the serum were determined using ELISA kits. Expression of caspase-3, TCF4, Wnt3a, and β-Catenin was evaluated using the Western blot assay.

RESULTS

The infarct area was significantly smaller in the DADLE groups than in the control group (P < 0.01). The histopathology score and serum levels of myocardial enzymes were significantly lower in the DADLE groups than in the control group (P < 0.01). DADLE significantly improved functions of the left ventricle (P < 0.01), decreased expression of caspase-3 (P < 0.01), TCF4 (P < 0.01), Wnt3a (P < 0.05), and β-Catenin (P < 0.01) compared with PBS.

CONCLUSIONS

The present study showed that DADLE protected the myocardium from MI/R through suppressing the expression of caspase-3, TCF4, Wnt3a, and β-Catenin and consequently improving functions of the left ventricle in I/R model mice. The TCF4/Wnt/β-Catenin signaling pathway might become a therapeutic target for MI/R treatment.

Targeting PI3K/p-Akt/eNOS, Nrf2/HO-1, and NF-κB/p53 signaling pathways by angiotensin 1-7 protects against liver injury induced by ischemia-reperfusion in rats

The liver is an important organ, and hepatic ischemia-reperfusion (IR) injury is a frequent pathophysiological process that can cause significant morbidity and mortality. Thus, our study aimed to investigate the effect of targeting PI3K/p-Akt/eNOS (phosphoinositide 3-kinase/phospho-protein kinase B/endothelial nitric oxide synthase), Nrf2/HO-1 (nuclear factor-erythroid 2-related factor-2/heme oxygenase-1), and NF-κB/p53 (nuclear factor-κB/tumor protein 53) signaling pathways by using angiotensin (1-7) [ang-(1-7)] against hepatic injury induced by IR. Thirty-two male rats were included in sham group, ang-(1-7)-treated group, hepatic IR group, and hepatic IR group treated with ang-(1-7). The levels of hepatic ang-(1-7), angiotensin II (Ang II), angiotensin-converting enzyme 2 (ACE2), HO-1, malondialdehyde (MDA), PI3K, and p-Akt were assessed. The expressions of eNOS and B-cell leukemia/lymphoma-2 (BCL-2) in the liver were determined. Histological assessment and immunohistochemical expression of NF-κB, p53, and Nrf2 were carried out. The levels of reduced glutathione (GSH), aspartate aminotransferase (AST), alanine aminotransferase (ALT), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in serum were estimated. Results showed that administration of ang-(1-7) to hepatic IR rats led to significant amelioration of hepatic damage through a histological evaluation that was associated with significant upregulation of the expressions of PI3K/p-Akt/eNOS and Nrf2/HO-1 with downregulation of NF-κB/p53 signaling pathways. In conclusion, PI3K/p-Akt/eNOS and Nrf2/HO-1 signaling pathways are involved in the protective effects of ang-(1-7) against hepatic damage induced by IR. Therefore, ang-(1-7) can be used to prevent hepatic IR, which occurs in certain conditions such as liver transplantation, hemorrhagic shock, and severe infection.

Sugarcane leaf polysaccharide exerts a therapeutic effect on cardiovascular diseases through necroptosis

Background

Necroptosis, a novel form of programmed cell death wherein the necrotic morphology is characterized by swelling of the cells, rupture of the plasma membrane, and dysfunction of the organelle, has been always observed in cardiovascular diseases. Sugarcane leaf polysaccharide (SLP) are primary components present in sugarcane leaves that exert cardiovascular protective effects. However, the positive effect of SLP and underlying mechanisms in myocardial ischemia-reperfusion (MI/R) remain unexplored.

Aim

In this study, the protective effects of SLP on MI/R injury were investigated under in vitro and in vivo conditions.

Methods

The protective effects of SLP on MI/R injury were assessed using tertiary butyl hydrogen peroxide (TBHP)-stimulated-H9c2 cells in the in vitro assay and using Sprague Dawley rats in the in vivo assay.

Results

In vitro, SLP significantly reversed TBHP-induced H9c2 cell death by inhibiting necroptosis and oxidative stress. SLP exerted antioxidant activity through the Nrf2/HO-1 pathway. SLP suppressed necroptosis by decreasing phosphorylation of RIP1, RIP3, and MLKL in TBHP-stimulated H9c2 cells. In vivo, SLP attenuated MI/R injury by decreasing the myocardial infarct area; increasing myeloperoxidase and superoxide dismutase levels; and reducing malondialdehyde, interleukin-6, and tumor necrosis factor-α levels.

The research development of STAT3 in hepatic ischemia-reperfusion injury

Ischemia-reperfusion injury (IRI) is a common complication of surgery, which can cause rapid deterioration of the liver function, increase the risk of graft rejection, and seriously affect the prognosis of patients. The signal transducer and activator of transcription 3 (STAT3) protein has been implicated in pathogenesis of IRI. STAT3 influences the mitochondria through multiple pathways and is also involved in apoptosis and other forms of programmed cell death. STAT3 is associated with Janus kinase (JAK), phosphoinositide-3 kinase (PI3K), and heme oxygenase-1 (HO-1) in liver IRI. The STAT3 pathway plays a dual role in IRI as it can also regulate lipid metabolism which may have potential for treating IRI fatty liver. In this review, we summarize research on the function of STAT3 in liver IRI to provide references for its application in the clinic.

Resveratrol promotes liver cell survival in mice liver-induced ischemia-reperfusion through unfolded protein response: a possible approach in liver transplantation

Background

Ischemia-reperfusion (I/R) of the liver is a multifactorial condition that happens during transplantation and surgery. The deleterious effects of I/R result from the acute production of reactive oxygen species (ROS), which can trigger immediate tissue damage and induce a series of destructive cellular responses, including apoptosis organ failure and inflammation. The production of ROS in the I/R process can damage the antioxidant system and cause liver damage. Resveratrol has been shown to have antioxidant properties in several investigations. Here, we address the therapeutic effect of resveratrol on I/R-induced liver injury by focusing on unfolded protein response (UPR) signaling pathway.

Methods

Five minutes before reperfusion, resveratrol was injected into the tail vein of mice. They were ischemic for 1 h and then re-perfused for 3 h before being slaughtered (I/R). The activity of liver enzymes and the expression levels of genes involved in the unfolded protein response pathway were used to measure the hepatic damage.

Results

Our results revealed that the low dose of resveratrol (0.02 and 0.2 mg/kg) post-ischemic treatment significantly reduced the ALT and AST levels. In addition, compared with the control group, the expression of UPR pathway genes GRP78, PERK, IRE1α, CHOP, and XBP1 was significantly reduced in the resveratrol group. In the mice that received lower doses of resveratrol (0.02 and 0.2 mg/kg), the histopathological changes induced by I/R were significantly improved; however, the highest dose (2 mg/kg) of resveratrol could not significantly protect and solve the I/R damage.

Conclusion

The findings of this study suggest that hepatic ischemia occurs after liver transplantation and that receiving low-dose resveratrol treatment before reperfusion may promote graft survival through inhibition of UPR arms, especially PERK and IRE1α.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40360-022-00611-4.

Targeting Nrf2 in ischemia-reperfusion alleviation: From signaling networks to therapeutic targeting

The nuclear factor erythroid 2-related factor 2 (Nrf2) is a master regulator of redox balance and it responds to various cell stresses that oxidative stress is the most well-known one. The Nrf2 should undergo nuclear translocation to exert its protective impacts and decrease ROS production. On the other hand, ischemic/reperfusion (I/R) injury is a pathological event resulting from low blood flow to an organ and followed by reperfusion. The I/R induces cell injury and organ dysfunction. The present review focuses on Nrf2 function in alleviation of I/R injury. Stimulating of Nrf2 signaling ameliorates I/R injury in various organs including lung, liver, brain, testis and heart. The Nrf2 enhances activity of antioxidant enzymes to reduce ROS production and prevent oxidative stress-mediated cell death. Besides, Nrf2 reduces inflammation via decreasing levels of pro-inflammatory factors including IL-6, IL-1β and TNF-α. Nrf2 signaling is beneficial in preventing apoptosis and increasing cell viability. Nrf2 induces autophagy to prevent apoptosis during I/R injury. Furthermore, it can interact with other molecular pathways including PI3K/Akt, NF-κB, miRNAs, lncRNAs and GSK-3β among others, to ameliorate I/R injury. The therapeutic agents, most of them are phytochemicals such as resveratrol, berberine and curcumin, induce Nrf2 signaling in I/R injury alleviation.

[D-Ala2, D-Leu5] Enkephalin Attenuates Hepatic Ischemia–Reperfusion Injury in Cirrhotic Rats

Background and Aims

Hepatic ischemia–reperfusion injury (IRI) is a common phenomenon that occurs after liver transplantation and liver tumor surgery. It can cause liver dysfunction and recovery failure after liver surgery, even leading to acute liver failure. Our aim is to investigate the protective effect and related potential mechanism of [D-Ala², D-Leu⁵] enkephalin (DADLE) treatment on hepatic IRI in cirrhotic livers of rats.

Methods

The models of liver cirrhosis and hepatic IRI were established with male Sprague–Dawley rats. DADLE at a dose series of 0.5, 1, or 5 mg·kg⁻¹ was injected intravenously to rats 10 min prior hepatic ischemia, followed by a 6- h reperfusion. The serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), histological changes, and liver cell apoptosis were used to assess liver IRI. The optimal dose of DADLE was assessed by using the Suzuki score and ALT and AST levels. We repeated the hepatic IRI procedure on the optimal dose of the DADLE group and the delta opioid receptor (DOR) antagonist natrindole hydrochloride (NTD) injection group. Serum ALT and AST levels, histological staining, hepatic apoptosis, and serum levels of tumor necrosis factor alpha (TNF-α) and interleukin 1 β (IL-1β) were measured. The expression of protein kinase B (Akt) and its downstream proteins were evaluated by using quantitative real-time polymerase chain action (qRT-PCR) and Western blotting.

Results

Compared with the control group, DADLE treatment at a dose of 5 mg·kg⁻¹ reduced the Suzuki score (mean: 5.8, range: 5.0–6.6 vs. mean: 8.0, range: 7.0–8.9), the ALT level (134.3 ± 44.7 vs. 247.8 ± 104.6), and the AST (297.1 ± 112.7 vs. 660.8 ± 104.3) level. DOR antagonist NTD aggravated hepatic IRI. Compared with the control group, DADLE treatment decreased the number of apoptosis cells and microphages and neutrophils, increased the expression of Akt and its mRNA to much higher levels, and upregulated the mRNA and protein expression of Bcl-2 and Bcl-2-associated death promoter (BAD).

Conclusion

DADLE treatment at a dose of 5 mg·kg⁻¹ injected intravenously 10 min prior hepatic ischemia could contain rats’ hepatic IRI by activating DOR in cirrhotic livers. The effects of DADLE could be offset by NTD. The potential molecular mechanism seems to be involved in the phosphatidylinositol-3-kinase (PI3K)/Akt pathway.

NRF2 assessment in discarded liver allografts: A role in allograft function and salvage

Antioxidant defence mechanisms, such as the nuclear factor-erythroid 2-related-factor-2 (NRF2) axis, are integral to oxidative stress responses and ischemic injury. Hepatic antioxidant capacity is contingent on parenchymal quality, and there is a need to develop new insights into key molecular mechanisms in marginal liver allografts that might provide therapeutic targets. This study examines the clinical relevance of NRF2 in donor livers and its response to normothermic machine perfusion (NMP). Discarded donor livers (n = 40) were stratified into a high NRF2 and low NRF2 group by quantifying NRF2 expression. High NRF2 livers had significantly lower transaminase levels, hepatic vascular inflammation and peri-portal CD3⁺ T cell infiltration. Human liver allografts (n = 8) were then exposed to 6-h of NMP and high NRF2 livers had significantly reduced liver enzyme alterations and improved lactate clearance. To investigate these findings further, we used a rat fatty-liver model, treating livers with an NRF2 agonist during NMP. Treated livers had increased NRF2 expression and reduced transaminase derangements following NMP compared to vehicle control. These results support the association of elevated NRF2 expression with improved liver function. Targeting this axis could have a rationale in future studies and NRF2 agonists may represent a supplemental treatment strategy for rescuing marginal donor livers.

Umbelliferone alleviates hepatic ischemia/reperfusion-induced oxidative stress injury via targeting Keap-1/Nrf-2/ARE and TLR4/NF-κB-p65 signaling pathway

Umbelliferone (UMB; 7-hydroxycoumarin) is a natural compound that exhibited a diversity of pharmacological activities. Its protective effects against various ischemia/reperfusion (IR) injuries, including heart, kidney, and testis, have been observed. However, their effect on hepatic IR is still not investigated yet. Here, this study was conducted to examine the potential protective role of UMB during the early phase of hepatic IR injury via targeting Keap-1/Nrf-2/ARE and its closely related signaling pathway, TLR4/NF-κB-p65. Experimentally, forty Wistar albino rats were randomly divided into 4 groups: Sham control group (received 1% carboxymethyl cellulose as a vehicle), UMB group (30 mg/kg/day, P.O.), IR group (subjected to complete hepatic IR injury), and IR + UMB group. Our results revealed that oral UMB effectively reduced the serum levels of ALT, AST, ALP, and LDH along with the restoration of oxidant/antioxidant status. At the molecular level, UMB markedly activated Nrf-2 expression and its down-streaming targets: HO-1, NQO1, GCLC, SOD3, and TNXRD1, along with Keap-1 down-regulation. Besides, UMB significantly down-regulated NF-κB-p65 and TLR4 expressions with subsequent decreased TNF-α and IL-1β levels coupled with the up-regulation of the IL-10 level. Finally, biochemical findings were confirmed by attenuation of histopathological changes in liver tissues. Together, UMB is a promising agent for the amelioration of liver tissues against IR-induced oxidative injury through activation of the Keap-1/Nrf-2/ARE signaling pathway along with suppression of its closely related signaling pathways: TLR4/NF-κB-p65. Illustrated diagram explored the prospective underlying protective mechanism of UMB against IR-induced hepatic damage.

Baicalein pre-treatment alleviates hepatic ischemia/reperfusion injury in mice by regulating the Nrf2/ARE pathway

Hepatic ischemia-reperfusion injury (HIRI) is caused by blood flow recovery following ischemia. Baicalein (BAI), a natural antioxidant used in traditional Chinese medicine, eliminates excessive free radicals and protects the structure of the cell membrane. However, its protective mechanism against HIRI is still unclear. The present study investigated underlying mechanism using a mouse HIRI model. Liver injury was evaluated using serum levels of alanine aminotransferase and aspartate aminotransferase, and hematoxylin-eosin staining was performed to evaluate the pathological changes in liver tissue. Apoptosis of hepatocytes was detected by TUNEL staining. The expression levels of reactive oxygen species (ROS), malondialdehyde (MDA) and superoxide dismutase (SOD) in the liver were detected to evaluate oxidative stress. Western blotting was performed to assess expression levels of nuclear factor E2-related factor 2 (Nrf2)/antioxidant response elements (ARE) pathway proteins in liver tissue. BAI pre-treatment significantly decreased elevation of serum aminotransferase levels induced by IR and alleviated histological damage to the liver. BAI decreased production of ROS and MDA in liver tissue induced by IR and increased the activity of SOD. At the same time, BAI inhibited apoptosis of liver cells induced by oxidative stress. Furthermore, BAI promoted the translocation of Nrf2 into the nucleus and increased the expression of total heme oxygenase-1 and NAD(P)H dehydrogenase quinone-1. The Nrf2 inhibitor ML385 reversed the protective effect of BAI on HIRI. These results indicated that BAI served a protective effect in HIRI by regulating the Nrf2/ARE pathway.

Lycopene alleviates hepatic ischemia reperfusion injury via the Nrf2/HO-1 pathway mediated NLRP3 inflammasome inhibition in Kupffer cells

Background

Lycopene is a naturally occurring carotenoid found in many fruits and vegetables, which has antioxidant effects. Although lycopene’s protective effect has been observed on ischemia reperfusion (IR) injury in different organs, the effect of lycopene on Kupffer cells (KCs) has not been clearly elucidated in IR-induced acute hepatic inflammatory injury.

Methods

Mice were administered with either olive oil (10 mL/kg body weight) as the control or lycopene (20 mg/kg body weight) by gavage for 2 weeks before undergoing hepatic IR injury.

Results

In this study, we observed that the levels of aspartate aminotransferases (AST), alanine aminotransferase (ALT), and the percentages of hepatocellular apoptosis in mice pretreated with lycopene were significantly lower than control mice. Lycopene inhibited F4/80+ macrophage and Ly6G+ neutrophil accumulation, which further decreased the levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin 6 (IL-6). Interestingly, lycopene induced increased autophagy in KCs, which was evidenced by elevated autophagosomes and the increased protein level of LC3B. In these KCs, lycopene-induced upregulation of autophagy inhibited NOD-like receptor family pyrin domain-containing 3 protein (NLRP3) inflammasome activation, which was demonstrated by the reduced mRNA and protein levels of NLRP3, cleaved caspase-1, an apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), and IL-1β. Furthermore, 3-methyladenine, an autophagy inhibitor, abolished lycopene’s inhibitory effect on the NLRP3 inflammasome in KCs, which led to increased hepatic IR injury. Intriguingly, we identified that the protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) were elevated in KCs isolated from IR-stressed mice pretreated with lycopene. Nrf2-siRNA or HO-1-siRNA could block the autophagy activation enhanced by lycopene in KCs, resulting in the activation of the NLRP3 inflammasome and aggravated hepatic IR injury.

Conclusions

Our findings demonstrated that lycopene promoted Nrf2/HO-1 pathway activation and further suppressed the NLRP3 inflammasome via enhancing KC autophagy, which alleviated hepatic IR injury.

Emerging recognition of the complement system in hepatic ischemia/reperfusion injury, liver regeneration and recovery (Review)

Hepatic ischemia/reperfusion injury (IRI) is a result of the ischemic cascade and may occur in the settings of liver trauma, resection and transplantation. Components of the complement system have been indicated to be mediators of hepatic IRI and regulators of liver regeneration. As such, their potential to mediate both beneficial and harmful effects render them key targets for therapy. In the present study, the mechanisms of complement mediating hepatic IRI were discussed with a focus on the different functions of complement in hepatic injury and liver recovery, and an explanation for this apparent paradox is provided, i.e. that the complement products C3a and C5a have an important role in liver damage; however, C3a and C5a are also necessary for liver regeneration. Furthermore, situated at the end of the complement activation cascade, the membrane attack complex is crucial in hepatic IRI and inhibiting the complex with a site-targeted murine complement inhibitor, complement receptor 2-CD59, may improve liver regeneration after partial hepatectomy, even when hepatectomy is combined with ischemia and reperfusion.

Scutellarin attenuates hypoxia/reoxygenation injury in hepatocytes by inhibiting apoptosis and oxidative stress through regulating Keap1/Nrf2/ARE signaling

Scutellarin is a natural flavonoid that has been found to exhibit anti-ischemic effect. However, the effect of scutellarin on hepatic hypoxia/reoxygenation (ischemia-reperfusion (I/R)) injury remains unknown. The aim of the present study was to explore the protective effect of scutellarin on I/R-induced injury in hepatocytes. Our results showed that scutellarin improved cell viability in hepatocytes exposed to hypoxia/reoxygenation (H/R). Scutellarin treatment resulted in decreased levels of reactive oxygen species (ROS) and malondialdehyde (MDA), and increased superoxide dismutase (SOD) activity in H/R-induced hepatocytes. In addition, scutellarin reduced cell apoptosis in H/R-stimulated hepatocytes, as proved by the decreased apoptotic rate. Moreover, scutellarin significantly up-regulated bcl-2 expression and down-regulated bax expression in hepatocytes exposed to H/R. Furthermore, scutellarin treatment caused significant decrease in Keap1 expression and increase in nuclear Nrf2 expression. Besides, scutellarin induced the mRNA expressions of heme oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase 1 (NQO1). Inhibition of Nrf2 significantly reversed the protective effects of scutellarin on H/R-stimulated hepatocytes. In conclusion, these findings demonstrated that scutellarin protected hepatocytes from H/R-induced oxidative injury through regulating the Keap1/Nrf2/ARE signaling pathway, indicating a potential relevance of scutellarin in attenuating hepatic I/R injury.

Endogenous opiates and behavior: 2017

This paper is the fortieth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2017 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

Enkephalins and ACTH in the mammalian nervous system

The pentapeptides methionine-enkephalin and leucine-enkephalin belong to the opioid family of peptides, and the non-opiate peptide adrenocorticotropin hormone (ACTH) to the melanocortin peptide family. Enkephalins/ACTH are derived from pro-enkephalin, pro-dynorphin or pro-opiomelanocortin precursors and, via opioid and melanocortin receptors, are responsible for many biological activities. Enkephalins exhibit the highest affinity for the δ receptor, followed by the μ and κ receptors, whereas ACTH binds to the five subtypes of melanocortin receptor, and is the only member of the melanocortin family of peptides that binds to the melanocortin-receptor 2 (ACTH receptor). Enkephalins/ACTH and their receptors exhibit a widespread anatomical distribution. Enkephalins are involved in analgesia, angiogenesis, blood pressure, embryonic development, emotional behavior, feeding, hypoxia, limbic system modulation, neuroprotection, peristalsis, and wound repair; as well as in hepatoprotective, motor, neuroendocrine and respiratory mechanisms. ACTH plays a role in acetylcholine release, aggressive behavior, blood pressure, bone maintenance, hyperalgesia, feeding, fever, grooming, learning, lipolysis, memory, nerve injury repair, neuroprotection, sexual behavior, sleep, social behavior, tissue growth and stimulates the synthesis and secretion of glucocorticoids. Enkephalins/ACTH are also involved in many pathologies. Enkephalins are implicated in alcoholism, cancer, colitis, depression, heart failure, Huntington's disease, influenza A virus infection, ischemia, multiple sclerosis, and stress. ACTH plays a role in Addison's disease, alcoholism, cancer, Cushing's disease, dermatitis, encephalitis, epilepsy, Graves' disease, Guillain-Barré syndrome, multiple sclerosis, podocytopathies, and stress. In this review, we provide an updated description of the enkephalinergic and ACTH systems.

MiR-128/SOX7 alleviates myocardial ischemia injury by regulating IL-33/sST2 in acute myocardial infarction

Acute myocardial infarction (AMI) induced by ischemia hypoxia severely threatens human life. Cell apoptosis of neurocytes was identified to mediate the pathogenesis, while the potential mechanism was still unclear. Sprague Dawley (SD) rats were used to establish the AMI rat model. Real-time polymerase chain reaction (PCR) and Western blot were performed to detect gene expression in mRNA and protein levels, respectively. A TUNEL assay was carried out to determine cell apoptosis. The relationship between SRY-related HMG-box (SOX7) and miR-128 was verified using luciferase reporter assay. The expression of SOX7 was decreased, while miR-128 was increased in AMI rats and ischemia hypoxia (IH) induced H9c2 cells. Hypoxia induction significantly promoted the expression of interleukin (IL)-33 and soluble ST2 (sST2), and also promoted cell apoptosis. MiR-128 targets SOX7 to regulate its expression. Down-regulated miR-128 reversed the effects of IH on expression of SOX7, sST2 and cell apoptosis, while down-regulated sST2 abolished the effects of miR-128 inhibitor. In addition, overexpressed IL-33 abolished the effects of miR-128 inhibitor that induced by IH on the expression of SOX7 and cell apoptosis. In vivo experiments validated the expression of miR-128 on cell apoptosis. The present study indicated that miR-128 modulated cell apoptosis by targeting SOX7, which was mediated by IL-33/sST2 signaling pathway.

Melatonin protects H9c2 cells against ischemia/reperfusion‑induced apoptosis and oxidative stress via activation of the Nrf2 signaling pathway

Melatonin can protect against cardiac ischemia/reperfusion (I/R) injury in models in vitro and in vivo by regulating oxidative stress and apoptosis; however, the precise molecular mechanisms involved remain unclear. Nuclear factor erythroid 2‑related factor 2 (Nrf2) is a transcription factor, which has been associated with the regulation of oxidative stress by translocating to the nucleus. Therefore, the present study investigated whether activation of the Nrf2 signaling pathway may be responsible for the protective effects of melatonin on I/R‑injured cardiomyocytes. In the present study, H9c2 cells were subjected to simulated I/R (SIR) injury and pretreated with melatonin and/or Nrf2 small interfering RNA (siRNA). Cell viability was detected via Cell Counting kit‑8 assay, apoptosis was examined by caspase‑3 cleavage and activity analysis; oxidative stress levels were determined by specific activity analysis assays. In the present study, it was observed that SIR induced significant increases in apoptosis and oxidative stress, and enhanced Nrf2 expression within H9c2 cells. Pretreatment with melatonin partially reversed these alterations and promoted Nrf2 nuclear translocation. Transfection with Nrf2 siRNA inhibited the protective effects of melatonin on SIR‑induced H9c2 cells. These results indicated that melatonin may protect H9c2 cells against I/R injury by reducing apoptosis and oxidative stress; this effect may be mediated via activation of the Nrf2 signaling pathway. Collectively, the results of the present study may suggest melatonin as a potential therapeutic agent against cardiac I/R injury.