Metformin protects against ischaemic myocardial injury by alleviating autophagy-ROS-NLRP3-mediated inflammatory response in macrophages

Pivotal role of endothelial cell autophagy in sepsis

Sepsis is a fatal organ dysfunction resulting from a disordered host response to infection. Endothelial cells (ECs) are usually the primary targets of inflammatory mediators in sepsis; damage to ECs plays a pivotal part in vital organ failure. In recent studies, autophagy was suggested to play a critical role in the ECs injury although the mechanisms by which ECs are injured in sepsis are not well elucidated. Autophagy is a highly conserved catabolic process that includes sequestrating plasma contents and transporting cargo to lysosomes for recycling the vital substrates required for metabolism. This pathway also counteracts microbial invasion to balance and retain homeostasis, especially during sepsis. Increasing evidence indicates that autophagy is closely associated with endothelial function. The role of autophagy in sepsis may or may not be favorable depending upon conditions. In the present review, the current knowledge of autophagy in the process of sepsis and its influence on ECs was evaluated. In addition, the potential of targeting EC autophagy for clinical treatment of sepsis was discussed.

The Protective Effect of Cyanidin-3-Glucoside on Myocardial Ischemia-Reperfusion Injury through Ferroptosis

This study was conducted to estimate the protective effect of Cyanidin-3-glucoside (C3G) on myocardial ischemia-reperfusion (IR) injury and to explore its mechanism. The rats were subjected to left anterior descending ligation and perfusion surgery. In vitro experiments were performed on H9c2 cells using the oxygen-glucose deprivation/reoxygenation (OGD/R) model. The results showed the administration of C3G reduced the infarction area, mitigated pathological alterations, inhibited ST segment elevation, and attenuated oxidative stress and ferroptosis-related protein expression. C3G also suppressed the expressions of USP19, Beclin1, NCOA4, and LC3II/LC3I. In addition, treatment with C3G relieved oxidative stress, downregulated LC3II/LC3I, reduced autophagosome number, downregulated TfR1 expression, and upregulated the expressions of FTH1 and GPX4 in OGD/R-induced H9c2 cells. C3G could inhibit the protein levels of USP19 and LC3II. C3G promoted K11-linked ubiquitination of Beclin1. Further evidence that C3G reduced ferroptosis and ameliorated myocardial I/R injury was demonstrated with the ferroptosis promoter RSL3. Taken together, C3G could be a potential agent to protect myocardium from myocardial I/R injury.

Berberine Protects Against NLRP3 Inflammasome via Ameliorating Autophagic Impairment in MPTP-Induced Parkinson's Disease Model

The NLR family pyrin domain containing 3 (NLRP3) inflammasome was reported to be regulated by autophagy and activated during inflammatory procession of Parkinson’s disease (PD). Berberine (BBR) is well-studied to play an important role in promoting anti-inflammatory response to mediate the autophagy activity. However, the effect of Berberine on NLRP3 inflammasome in PD and its potential mechanisms remain unclear. Hence, in this study, we investigated the effects of BBR on 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice, by evaluating their behavioral changes, dopaminergic (DA) neurons loss, neuroinflammation, NLRP3 inflammasome and autophagic activity. BBR was also applied in BV2 cells treated with 1-methyl-4-pehnyl-pyridine (MPP+). The autophagy inhibitor 3-Methyladenine (3-MA) was administrated to block autophagy activity both in vivo and in vitro. In our in vivo studies, compared to MPTP group, mice in MPTP + BBR group showed significant amelioration of behavioral disorders, mitigation of neurotoxicity and NLRP3-associated neuroinflammation, enhancement of the autophagic process in substantia nigra (SN). In vitro, compared to MPP+ group, BBR significantly decreased the level of NLRP3 inflammasome including the expressions of NLRP3, PYD and CARD domain containing (PYCARD), cleaved caspase 1 (CASP1), and mature interleukin 1 beta (IL1B), via enhancing autophagic activity. Furthermore, BBR treatment increased the formation of autophagosomes in MPP+-treated BV2 cells. Taken together, our data indicated that BBR prevents NLRP3 inflammasome activation and restores autophagic activity to protect DA neurons against degeneration in vivo and in vitro, suggesting that BBR may be a potential therapeutic to treat PD.

Rosuvastatin protects against coronary microembolization-induced cardiac injury via inhibiting NLRP3 inflammasome activation

Coronary microembolization (CME), a common reason for periprocedural myocardial infarction (PMI), bears very important prognostic implications. However, the molecular mechanisms related to CME remain largely elusive. Statins have been shown to prevent PMI, but the underlying mechanism has not been identified. Here, we examine whether the NLRP3 inflammasome contributes to CME-induced cardiac injury and investigate the effects of statin therapy on CME. In vivo study, mice with CME were treated with 40 mg/kg/d rosuvastatin (RVS) orally or a selective NLRP3 inflammasome inhibitor MCC950 intraperitoneally (20 mg/kg/d). Mice treated with MCC950 and RVS showed improved cardiac contractile function and morphological changes, diminished fibrosis and microinfarct size, and reduced serum lactate dehydrogenase (LDH) level. Mechanistically, RVS decreased the expression of NLRP3, caspase-1, interleukin-1β, and Gasdermin D N-terminal domains. Proteomics analysis revealed that RVS restored the energy metabolism and oxidative phosphorylation in CME. Furthermore, reduced reactive oxygen species (ROS) level and alleviated mitochondrial damage were observed in RVS-treated mice. In vitro study, RVS inhibited the activation of NLRP3 inflammasome induced by tumor necrosis factor α plus hypoxia in H9c2 cells. Meanwhile, the pyroptosis was also suppressed by RVS, indicated by the increased cell viability, decreased LDH and propidium iodide uptake in H9c2 cells. RVS also reduced the level of mitochondrial ROS generation in vitro. Our results indicate the NLRP3 inflammasome-dependent cardiac pyroptosis plays an important role in CME-induced cardiac injury and its inhibitor exerts cardioprotective effect following CME. We also uncover the anti-pyroptosis role of RVS in CME, which is associated with regulating mitochondrial ROS.

Association of Preadmission Metformin Use and Prognosis in Patients With Sepsis and Diabetes Mellitus: A Systematic Review and Meta-Analysis

BACKGROUND AND AIM

A growing body of evidence suggests that preadmission metformin use could decrease the mortality of septic patients with diabetes mellitus (DM); however, the findings remain controversial. Therefore, this meta-analysis was conducted on available studies to confirm the relationship between preadmission metformin use and mortality in patients with sepsis and DM.

METHODS

A comprehensive search of the PubMed, Embase, and Cochrane Library databases was performed for studies published before August 8, 2021. Observational studies assessing the correlation between metformin use and mortality in patients with sepsis and DM were considered eligible studies. We used the Newcastle-Ottawa Scale (NOS) to assess the outcome quality of each included article. Furthermore, the odds ratios (ORs) and 95% confidence intervals (CIs) were analyzed using the inverse variance method with random effects modeling.

RESULTS

Eleven articles including 8195 patients were analyzed in this meta-analysis. All the included articles were scored as low risk of bias. Our results showed that preadmission metformin use had a lower mortality rate (OR, 0.74; 95% CIs, 0.62-0.88, P < 0.01) in patients with sepsis and DM. Surprisingly, there was no statistically significant difference in the levels of serum creatinine (weighted mean difference (WMD), 0.36; 95% CIs, -0.03-0.75; P = 0.84) and lactic acid (WMD, -0.16; 95% CIs, -0.49-0.18; P = 0.07) between preadmission metformin use and non-metformin use.

CONCLUSIONS

This study is the most comprehensive meta-analysis at present, which shows that preadmission metformin use may reduce mortality and not increase the levels of serum creatinine and lactic acid in adult patients with sepsis and DM. Therefore, these data suggest that the potential efficacy of metformin could be assessed in future clinical studies.

SYSTEMATIC REVIEW REGISTRATION

https://inplasy.com/?s=INPLASY2021100113, identifier INPLASY2021100113.

Pharmacological Modulation of Cardiac Remodeling after Myocardial Infarction

Cardiac remodeling describes a series of structural and functional changes in the heart after myocardial infarction (MI). Adverse post-MI cardiac remodeling directly jeopardizes the recovery of cardiac functions and the survival rate in MI patients. Several classes of drugs are proven to be useful to reduce the mortality of MI patients. However, it is an ongoing challenge to prevent the adverse effects of cardiac remodeling. The present review aims to identify the pharmacological therapies from the existing clinical drugs for the treatment of adverse post-MI cardiac remodeling. Post-MI cardiac remodeling is a complex process involving ischemia/reperfusion, inflammation, cell death, and deposition of extracellular matrix (ECM). Thus, the present review included two parts: (1) to examine the basic pathophysiology in the cardiovascular system and the molecular basis of cardiac remodeling and (2) to identify the pathological aspects of cardiac remodeling and the potential of the existing pharmacotherapies. Ultimately, the present review highlights drug repositioning as a strategy to discover effective therapies from the existing drugs against post-MI cardiac remodeling.

Lychee seed polyphenol inhibits Aβ-induced activation of NLRP3 inflammasome via the LRP1/AMPK mediated autophagy induction

Emerging evidence indicates that the enhancement of microglial autophagy inhibits the NLRP3 inflammasome mediated neuroinflammation in Alzheimer's disease (AD). Meanwhile, low density lipoprotein receptor-related protein 1 (LRP1) highly expressed in microglia is able to negatively regulate neuroinflammation and positively regulate autophagy. In addition, we have previously reported that an active lychee seed fraction enriching polyphenol (LSP) exhibits anti-neuroinflammation in Aβ-induced BV-2 cells. However, its molecular mechanism of action is still unclear. In this study, we aim to investigate whether LSP inhibits the NLRP3 inflammasome mediated neuroinflammation and clarify its molecular mechanism in Aβ-induced BV-2 cells and APP/PS1 mice. The results showed that LSP dose- and time-dependently activated autophagy by increasing the expression of Beclin 1 and LC3II in BV-2 cells, which was regulated by the upregulation of LRP1 and its mediated AMPK signaling pathway. In addition, both the Western blotting and fluorescence microscopic results demonstrated that LSP could significantly suppress the activation of NLRP3 inflammasome by inhibiting the expression of NLRP3, ASC, the cleavage of caspase-1, and the release of IL-1β in Aβ(1-42)-induced BV-2 cells. In addition, the siRNA LRP1 successfully abolished the effect of LSP on the activation of AMPK and its mediated autophagy, as well as the inhibition of NLRP3 inflammasome. Furthermore, LSP rescued PC-12 cells which were induced by the conditioned medium from Aβ(1-42)-treated BV-2 cells. Moreover, LSP improved the cognitive function and inhibited the NLRP3 inflammasome in APP/PS1 mice. Taken together, LSP inhibited the NLRP3 inflammasome-mediated neuroinflammation in the in vitro and in vivo models of AD, which was closely associated with the LRP1/AMPK-mediated autophagy. Thus, the findings from this study further provide evidences for LSP serving as a potential drug for the treatment of AD in the future.

MTMR14 protects against cerebral stroke through suppressing PTEN-regulated autophagy

The phosphoinositide phosphatase, myotubularinrelated protein 14 (MTMR14), plays a critical role in the regulating autophagy. However, its functional contribution to neuronal autophagy is still unclear. In the present study, we attempted to explore the effects of MTMR14 on ischemic stroke progression, as well as the underlying molecular mechanisms. Oxygen-glucose deprivation/reoxygenation (OGDR)-induced primary cortical neurons and pheochromocytoma (PC12) cells, and middle cerebral artery occlusion (MCAO)-operated mice were used to establish cerebral ischemia/reperfusion (I/R) injury in vitro and in vivo, respectively. OGDR treatment markedly decreased the expression of MTMR14 expression from mRNA and protein levels in the cultured primary neurons and PC12 cells. Functional analysis showed that OGDR-reduced cell viability was further accelerated by MTMR14 knockdown. On the contrary, MTMR14 over-expression significantly rescued the cell survival in OGDR-exposed cells. Moreover, autophagic markers including LC3BII and Beclin 1 were highly up-regulated in OGDR-incubated neurons and PC12 cells, while being further exacerbated by MTMR14 deletion. However, promoting MTMR14 dramatically alleviated LC3BII and Beclin 1 expression levels stimulated by OGDR. Importantly, we found that MTMR14-regulated autophagy was through its interactions with phosphatase and tensin homolog (PTEN). MTMR14 negatively modulated PTEN protein expression levels in OGDR-exposed cells. In vivo, MCAO-operated mice exhibited significantly reduced expression of MTMR14 in the ischemic penumbra tissues. After MCAO operation, MTMR14 over-expression effectively reduced infarct volume and neurological deficits scores, along with decreased activation of LC3B in neurons. Consistently, MCAO-increased PTEN, LC3BII and Beclin 1 were repressed by MTMR14 in mice. An interaction between MTMR14 and PTEN in response to MCAO was confirmed in vivo. Together, these results indicated the neuroprotective effects of MTMR14 on modulating PTEN-dependent excessive autophagy during cerebral I/R injury. Thus, targeting MTMR14 may provide feasible therapy for ischemic stroke onset and progression.