Maresin1 alleviates neuroinflammation by inhibiting caspase-3/ GSDME-mediated pyroptosis in mice cerebral ischemia-reperfusion model.

OBJECTIVE: To explore the mechanism of Maresin1 in reducing cerebral ischemia-reperfusion injury. MATERIALS AND METHODS: Male C57BL/6 mice were randomly divided (n = 5 in each group), and focal middle cerebral artery occlusion (MCAO) model was used to simulate cerebral ischemia/reperfusion injury. TTC and the Longa score were used to detect the degree of neurological deficits. Western blot was used to detect the expression levels of GSDME, GSDME-N, caspase-3 and cleaved caspase-3 in cerebral ischemic penumbra tissue, and immunofluorescence was used to detect the expression levels of GSDME-N. The mRNA expression levels of GSDME and pro-inflammatory cytokines (IL-1ß, IL-6 and TNF-α) were detected by RT-PCR. RESULTS: Compared with sham group, GSDME mRNA levels in MCAO group were significantly increased at 12 h and 24 h after reperfusion, and GSDME and GSDME-N significantly increased at 6-48 h after reperfusion. Compared with sham group, the percentage of infarct size, the Longa score, the mRNA expression levels of IL-1ß, IL-6 and TNF-α, and GSDME, GSDME-N, caspase-3 and cleaved caspase-3 in MCAO group was significantly increased. Then, the percentage of infarct size and the Longa score significantly decreased after MaR1 administration, the mRNA expression levels of IL-1ß and IL-6 downregulated, and GSDME, GSDME-N, caspase-3 and cleaved caspase-3 were also reduced. After administration of Z-DEVD-FMK(ZDF), the expression of caspase-3, cleaved caspase-3 and GSDME-N was decreased, which in MCAO+MaR1+ZDF group was not statistically significant compared with MCAO+ ZDF group. CONCLUSION: Maresin1 alleviates cerebral ischemia/reperfusion injury by inhibiting pyroptosis mediated by caspase-3/GSDME pathway and alleviating neuroinflammation.

Maresin1 alleviates liver ischemia/reperfusion injury by reducing liver macrophage pyroptosis.

BACKGROUND: Cell pyroptosis has a strong proinflammatory effect, but it is unclear whether pyroptosis of liver macrophages exacerbates liver tissue damage during liver ischemia‒reperfusion (I/R) injury. Maresin1 (MaR1) has a strong anti-inflammatory effect, and whether it can suppress liver macrophage pyroptosis needs further study. METHODS: This study aimed to investigate whether MaR1 can alleviate liver I/R injury by inhibiting macrophage pyroptosis. The effects of MaR1 on cell pyroptosis and mitochondrial damage were studied by dividing cells into control, hypoxia/reoxygenation, and hypoxia/reoxygenation + MaR1 groups. Knocking out RORa was used to study the mechanism by which MaR1 exert its protective effects. Transcriptome analysis, qRT‒PCR and Western blotting were used to analyze gene expression. Untargeted metabolomics techniques were used to analyze metabolite profiles in mice. Flow cytometry was used to assess cell death and mitochondrial damage. RESULTS: We first found that MaR1 significantly reduced liver I/R injury. We observed that MaR1 decreased liver I/R injury by inhibiting liver macrophage pyroptosis. Then, we discovered that MaR1 promotes mitochondrial oxidative phosphorylation, increases the synthesis of ATP, reduces the generation of ROS, decreases the impairment of mitochondrial membrane potential and inhibits the opening of mitochondrial membrane permeability transition pores. MaR1 inhibits liver macrophage pyroptosis by protecting mitochondria. Finally, we found that MaR1 exerts mitochondrial protective effects through activation of its nuclear receptor RORa and the PI3K/AKT signaling pathway. CONCLUSIONS: During liver I/R injury, MaR1 can reduce liver macrophage pyroptosis by reducing mitochondrial damage, thereby reducing liver damage.

The pro-resolving lipid mediator Maresin 1 protects against cerebral ischemia/reperfusion injury by attenuating the pro-inflammatory response.

Inflammation plays a crucial role in acute ischemic stroke pathogenesis. Macrophage-derived Maresin 1 (MaR1) is a newly uncovered mediator with potent anti-inflammatory abilities. Here, we investigated the effect of MaR1 on acute inflammation and neuroprotection in a mouse brain ischemia reperfusion (I/R) model. Male C57 mice were subjected to 1-h middle cerebral artery occlusion (MCAO) and reperfusion. By the methods of 2,3,5-triphenyltetrazolium chloride, haematoxylin and eosin or Fluoro-Jade B staining, neurological deficits scoring, ELISA detection, immunofluorescence assay and western blot analysis, we found that intracerebroventricular injection of MaR1 significantly reduced the infarct volume and neurological defects, essentially protected the brain tissue and neurons from injury, alleviated pro-inflammatory reactions and NF-κB p65 activation and nuclear translocation. Taken together, our results suggest that MaR1 significantly protects against I/R injury probably by inhibiting pro-inflammatory reactions.

Resolvin D1 promotes the interleukin-4-induced alternative activation in BV-2 microglial cells.

BACKGROUND: Microglia play key roles in innate immunity, homeostasis, and neurotropic support in the central nervous system. Similar to macrophages, microglia adopt two different activation phenotypes, the classical and alternative activation. Resolvin D1 (RvD1) is considered to display potent anti-inflammatory and pro-resolving actions in inflammatory models. In this present study, we investigate the effect of RvD1 on IL-4-induced alternative activation in murine BV-2 microglial cells. METHODS: BV-2 cells were incubated with RvD1 alone, IL-4 alone, or the combination of RvD1 and IL-4. Western blot and immunofluorescence were performed to detect protein levels of alternative activation markers arginase 1 (Arg1), chitinase 3-like 3 (Ym1). Moreover, we investigated the effects of RvD1 on IL-4-induced activation of signal transducer and activators of transcription 6 (STAT6) and peroxisome proliferator-activated receptor gamma (PPARγ). RESULTS: RvD1 promoted IL-4-induced microglia alternative activation by increasing the expression of Arg1 and Ym1. RvD1 also enhanced phosphorylation of STAT6, nuclear translocation of PPARγ and the DNA binding activity of STAT6 and PPARγ. These effects were reversed by butyloxycarbonyl-Phe-Leu-Phe-Leu-Phe (a formyl peptide receptor 2 antagonist). Further, the effects of RvD1 and IL-4 on Arg1 and Ym1 were blocked by the application of leflunomide (a STAT6 inhibitor) or GW9662 (a PPARγ antagonist). CONCLUSIONS: Our studies demonstrate that RvD1 promotes IL-4-induced alternative activation via STAT6 and PPARγ signaling pathways in microglia. These findings suggest that RvD1 may have therapeutic potential for neuroinflammatory diseases.

CXCR3 alleviates renal ischemia­reperfusion injury via increase of Tregs.

Increasing evidence has demonstrated that regulatory T cells (Tregs) suppress innate immunity, as well as protect the kidneys from ischemia­reperfusion injury (IRI) and offer a potentially effective strategy to prevent or alleviate renal IRI. The present study explored whether C­X­C motif chemokine receptor 3 (CXCR3) alleviated renal IRI by increasing Tregs. Male C57BL/6J mice were divided into sham­surgery, IRI, CXCR3 overexpression (OE­CXCR3)+IRI, PC61+IRI and OE­CXCR3+PC61+IRI groups. Histopathological examination of the kidney was carried out using hematoxylin­eosin and Masson staining. The levels of serum creatinine (Scr) and blood urea nitrogen (BUN) were measured. Blood and kidney levels of IL­6, TNF­α, C­C motif chemokine ligand (CCL)­2 and IL­10 were detected by ELISA and western blotting. The levels of superoxide dismutase (SOD), glutathione peroxidase (GSH­Px) and malondialdehyde (MDA) in kidney tissues were also measured to assess oxidative stress. The population of Tregs in the kidney was assessed using flow cytometry. The results demonstrated that administration of OE­CXCR3 to IRI mice significantly decreased the levels of Scr, BUN, IL­6, TNF­α, CCL­2 and MDA, increased the levels of IL­10, SOD and GSH­Px, and mitigated the morphologic injury and fibrosis induced by IR compared with the IRI group. In addition, administration of OE­CXCR3 induced significant reductions in the expression levels of fibrosis­related markers, including fibronectin and type IV collagen, and increased the number of Tregs. These roles of OE­CXCR3 were significantly neutralized following deletion of Tregs with PC61 (anti­CD25 antibody). Together, the present study demonstrated that injection of OE­CXCR3 lentiviral vectors into animal models can alleviate renal IRI by increasing the number of Tregs. The results may be a promising approach for the treatment of renal IRI.

Maresin 1 attenuates the inflammatory response and mitochondrial damage in mice with cerebral ischemia/reperfusion in a SIRT1-dependent manner.

Maresin 1 (MaR1) confers brain-protective effects against cerebral ischemia/reperfusion (I/R) injury. Activation of silent information regulator 1 (SIRT1) signaling has also been demonstrated to inhibit cerebral I/R injury. We hypothesize that MaR1 may protect against cerebral I/R injury by activating SIRT1 signaling. The present study investigated the protective effect of MaR1 treatment on cerebral I/R injury and elucidated the potential mechanisms. Mice were exposed to the treatment in the presence or absence of MaR1 or the SIRT1 inhibitor EX527 and then subjected to the middle cerebral artery occlusion (MCAO) operation. MaR1 conferred a brain-protective effect by up-regulating SIRT1 and Bcl2 expression, down-regulating acetylated neuclear factor kappaB (AC-NF-κB) and Bax expression, reducing pro-inflammatory factor levels (IL-1, IL-6 and TNF-α), increasing the mitochondrial membrane potential, and diminishing neuronal degeneration, the infarct size and the neurological defects of cerebral I/R. These protective effects were partially blocked by the SIRT1 inhibitor EX527, indicating that SIRT1 signaling might be specifically involved in the protection provided by MaR1 against cerebral I/R injury. In summary, our results demonstrate that MaR1 treatment attenuates cerebral I/R injury by reducing inflammatory responses and mitochondrial damage via activation of SIRT1 signaling.

Higd1a Protects Cells from Lipotoxicity under High-Fat Exposure.

Hypoxia-inducible gene domain family member 1A (Higd1a) has recently been reported to protect cells from hypoxia by helping to maintain normal mitochondrial function. The potential induction of Higd1a under high-fat exposure and whether it could protect cells from oxidative stress attracted our attention. Initially, 0.4 mM oleic acid and 0.2 mM palmitate were added to the growth media of HepG2 and LO2 cells for 72 hours. We discovered increased Higd1a expression, and knocking down Higd1a impaired mitochondrial transmembrane potential and induced cell apoptosis. We then identified that elevated reactive oxygen species (ROS) is responsible for increased Higd1a expression. Furthermore, we found that ROS promoted Higd1a expression by upregulating HIF-1a and PGC-1a expressions, and these two proteins could exert synergistic effects in inducing Higd1a expression. Taken together, these data suggest that Higd1a plays positive roles in protecting cells from oxidative stress, and ROS could induce Higd1a expression by upregulating PGC-1a and HIF-1a expressions.

DAPK1-ERK signal mediates oxygen glucose deprivation reperfusion induced apoptosis in mouse N2a cells.

AIMS: Death-associated protein kinase 1 (DAPK1) is a kinase found to promote neuronal apoptosis induced by ischemia. Extracellular signal-regulated kinase (ERK) was identified as a key molecule in DAPK1 signaling. However, the mechanisms of neuronal ischemia reperfusion injury remain unknown. Here, we investigate the influence of DAPK1-ERK signal on neuronal apoptosis following ischemia reperfusion. METHODS: Mouse N2a cells were used in this study and primary cultured neurons along with mice were adopted as supplements. Oxygen glucose deprivation (OGD) or administration of N-methyl-d-aspartate (NMDA) and glycine was performed on cells while middle cerebral artery occlusion (MCAO) model on mice. DAPK1 knocking down was achieved by lentiviral-delivered shRNA. Protein expressions were evaluated by western blots. Protein-protein binding was confirmed by co-immunoprecipitation and immunofluorescent assay. Apoptosis of cells was measured by flow cytometry and lacate dehydrogenase (LDH) leakage assay. RESULTS: Ischemia reperfusion resulted in increased DAPK1 and ERK activation as well as aggravated apoptosis in a time-dependent manner. DAPK1 was proved to bind to ERK during reperfusion following OGD, MCAO and excitotoxicity model. Interception of this binding by knocking down DAPK1 led to nuclear translocation of ERK and reduced apoptosis. CONCLUSION: Our study revealed the DAPK1-ERK signal as a potential mechanism contributing to neuronal apoptosis in response to ischemia reperfusion. Disruption of this signal pathway could be a promising therapeutic target against stroke.

MiR-221 mediates the epithelial-mesenchymal transition of hepatocellular carcinoma by targeting AdipoR1.

Recent studies have shown that miRNAs play vital roles in tumorigenesis. However, their effects on the epithelial-mesenchymal transition (EMT) in hepatocellular carcinoma (HCC) need to be better understood. Our present study demonstrates that miR-221, which is overexpressed in HCC tissues, promotes EMT in HCC cell lines by targeting a new gene, AdipoR1. First, overexpression of miR-221 was identified in 40 pairs of human HCC tumor and matched normal tissues. Moreover, we found that elevated miR-221 was strongly associated with worse clinicopathologic features in HCC patients. Next, the loss of miR-221 inhibited, but its restoration enhanced, the EMT process in HCC cell lines. Furthermore, bioinformatics software predicted that AdipoR1 would be a direct target of miR-221. We then observed negative regulation of miR-221 on AdipoR1 protein expression, and direct binding between them was further verified using dual-luciferase assays. In addition, knockdown of AdipoR1 resulted in promotion of the EMT in HCC cells, and AdipoR1 overexpression reversed the miR-221-induced EMT. Lastly, we found that the JAK/STAT3 pathway may be involved in the AdipoR1-mediated EMT process. In conclusion, miR-221 acts as a promoter of the EMT process in HCC cells by targeting AdipoR1, and this study highlights the potential effects of miR-221 on the prognosis and treatment of HCC.

Carvedilol for portal hypertension in cirrhosis: systematic review with meta-analysis.

OBJECTIVE: To assess the clinical and haemodynamic effects of carvedilol for patients with cirrhosis and portal hypertension. DESIGN: A systematic review and meta-analysis. DATA SOURCES: We searched PubMed, Cochrane library databases, EMBASE and the Science Citation Index Expanded through December 2015. Only randomised controlled trials (RCTs) were included. OUTCOME MEASURE: We calculated clinical outcomes (all-cause mortality, bleeding-related mortality, upper gastrointestinal bleeding) as well as haemodynamic outcomes (hepatic venous pressure (HVPG) reduction, haemodynamic response rate, post-treatment arterial blood pressure (mean arterial pressure; MAP) and adverse events). RESULTS: 12 RCTs were included. In 7 trials that looked at haemodynamic outcomes compared carvedilol versus propranolol, showing that carvedilol was associated with a greater reduction (%) of HVPG within 6 months (mean difference -8.49, 95% CI -12.36 to -4.63) without a greater reduction in MAP than propranolol. In 3 trials investigating differences in clinical outcomes between carvedilol versus endoscopic variceal band ligation (EVL), no significant differences in mortality or variceal bleeding were demonstrated. 1 trial compared clinical outcomes between carvedilol versus nadolol plus isosorbide-5-mononitrate (ISMN), and showed that no significant difference in mortality or bleeding had been found. 1 trial comparing carvedilol versus nebivolol showed a greater reduction in HVPG after 14 days follow-up in the carvedilol group. CONCLUSIONS: Carvedilol may be more effective in decreasing HVPG than propranolol or nebivolol and it may be as effective as EVL or nadolol plus ISMN in preventing variceal bleeding. However, the overall quality of evidence is low. Further large-scale randomised studies are required before we can make firm conclusions. TRIAL REGISTRATION NUMBER: CRD42015020542.