Emodin alleviates LPS-induced myocardial injury through inhibition of NLRP3 inflammasome activation

Songorine ameliorates LPS-induced sepsis cardiomyopathy by Wnt/β-catenin signaling pathway-mediated mitochondrial biosynthesis

Septic cardiomyopathy (SCM) is manifested by impairment of cardiac contractile function with myocardial mitochondrial dysregulation. Natural product, songorine (SGR), a diterpenoid alkaloid derived from the lateral root of Aconitum carmichaeli, has been reported for the treatment of heart failure. Here, the protective role of SGR in heart injury of SCM was investigated and its underlying action of mechanism was explored. Firstly, the mouse and cardiomyocytes (H9C2 cell) SCM model induced by LPS were established to evaluate the therapeutic effect of SGR. The in vivo results exhibited that SGR rescued the survival rate of SCM mice, restored the loss of ejection fraction (EF) and fractional shortening (FS), and reduced left ventricular systolic diameter and left ventricular diastole diameter (LVIDs, LVIDd) by echocardiography. SGR improved the mitochondrial biosynthesis and myocardial fiber structure and arranged them neatly by transmission electron microscope (TEM). Further, SGR inhibited inflammatory targets myeloperoxidase (MPO) and tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and plasminogen activator inhibitor-1 (PAI-1). And SGR activated the mitochondrial biosynthesis-related peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), β-catenin, and matrix metallopeptidase 2 (MMP2) proteins. Meanwhile, the in vitro results showed that SGR promoted the increased the myocardial H9C2 cell viability, and mitochondrial biosynthesis and structure. SGR also blocked the inflammatory factors and reversed PGC-1α, β-catenin, and MMP2 in vitro, while SGR alleviated the myocardial cell apoptosis via flow cytometry. The findings indicate that SGR mitigates sepsis-caused myocardial damage by Wnt/β-catenin signaling pathway-mediated mitochondrial biosynthesis. SGR may be a promising candidate for treatment of SCM.

Pyroptosis in sepsis induced organ dysfunction

As an uncontrolled inflammatory response to infection, sepsis and sepsis induced organ dysfunction are great threats to the lives of septic patients. Unfortunately, the pathogenesis of sepsis is complex and multifactorial, which still needs to be elucidated. Pyroptosis is a newly discovered atypical form of inflammatory programmed cell death, which depends on the Caspase-1 dependent classical pathway or the non-classical Caspase-11 (mouse) or Caspase-4/5 (human) dependent pathway. Many studies have shown that pyroptosis is related to sepsis. The Gasdermin proteins are the key molecules in the membrane pores formation in pyroptosis. After cut by inflammatory caspase, the Gasdermin N-terminal fragments with perforation activity are released to cause pyroptosis. Pyroptosis is closely related to the occurrence and development of sepsis induced organ dysfunction. In this review, we summarized the molecular mechanism of pyroptosis, the key role of pyroptosis in sepsis and sepsis induced organ dysfunction, with the aim to bring new diagnostic biomarkers and potential therapeutic targets to improve sepsis clinical treatments.

Long Noncoding RNA SOX2OT Ameliorates Sepsis-Induced Myocardial Injury by Inhibiting Cellular Pyroptosis Through Mediating the EZH2/Nrf-2/NLRP3 Signaling Pathway

Objective

Cellular pyroptosis is a pro-inflammatory mode of programmed cell death that has been identified in recent years, and studies have shown that the LncRNA SOX2OT regulates myocardial injury during sepsis, but the exact regulatory mechanism is unclear. The aim of this study was to assess the role of SOX2OT in regulating cardiomyocyte injury during sepsis cardiomyopathy.

Methods

Rat cardiomyocytes, C57BL/6 mice, and transgenic mice were divided into four groups: control, LPS, LPS+ knockout LncRNA SOX2OT, and LPS+ overexpression LncRNA SOX2OT. Inflammatory factor levels were detected by qPCR. Associated proteins and gene expression were detected by Western blotting and qPCR. Dual luciferase was used to detect the target genes of SOX2OT. Nrf2 and EZH2 knockdown and overexpression cell lines were established, and the expression of related genes was detected by qPCR.

Results

Results In this study, we found that SOX2OT knockdown exacerbated LPS-induced levels of inflammatory factors and procalcitoninogen (PCT), and increased the expression of pyroptosis-related proteins and LDH. The results of dual luciferase reporter gene assay showed that EZH2 is the target gene of SOX2OT, and overexpression of SOX2OT decreased the expression of EZH2; we also found that knockdown of EZH2 in H9c2 cells decreased the expression of Nrf2, which was positively correlated with the expression level of NLRP3. Further in vivo results showed that overexpression of SOX2OT attenuated SIMD (sepsis-induced myocardial dysfunction), as evidenced by improved myocardial structural integrity and reduced inflammatory cell infiltration. The expression of pyroptosis-related proteins and LDH was significantly increased in the mice in the LPS group; this effect was reversed by overexpression of SOX2OT, and potentiated by knockdown of SOX2OT.

Conclusion

Our data reveal a novel mechanism by which SOX2OT inhibits cardiomyocyte sepsis through the EZH2/Nrf-2/NLRP3 pathway, thereby attenuating septic myocardial injury, which may contribute to the development of new therapeutic strategies.

Pyroptosis in myocardial ischemia/reperfusion and its therapeutic implications

Ischemic heart disease, a prevalent cardiovascular disease with global significance, is associated with substantial morbidity. Timely and successful reperfusion is crucial for reducing infarct size and enhancing clinical outcomes. However, reperfusion may induce additional myocardium injury, manifesting as myocardial ischemia/reperfusion (MI/R) injury. Pyroptosis is a regulated cell death pathway, the signaling pathway of which is activated during MI/R injury. In this process, the inflammasomes are triggered, initiating the cleavage of gasdermin proteins and pro-interleukins, which results in the formation of membrane pores and the maturation and secretion of inflammatory cytokines. Numerous preclinical evidence underscores the pivotal role of pyroptosis in MI/R injury. Inhibiting pyroptosis is cardioprotective against MI/R injury. Although certain agents exhibiting promise in preclinical studies for attenuating MI/R injury through inhibiting pyroptosis have been identified, the suitability of these compounds for clinical trials remains untested. This review comprehensively summarizes the recent developments in this field, with a specific emphasis on the impact of pyroptosis on MI/R injury. Deciphering these findings not only sheds light on new disease mechanisms but also paves the way for innovative treatments. And then the exploration of the latest advances in compounds that inhibit pyroptosis in MI/R is discussed, which aims to provide insights into potential therapeutic strategies and identify avenues for future research in the pursuit of effective clinical interventions.

Cardioprotective properties of OMT-28, a synthetic analog of omega-3 epoxyeicosanoids

OMT-28 is a metabolically robust small molecule developed to mimic the structure and function of omega-3 epoxyeicosanoids. However, it remained unknown to what extent OMT-28 also shares the cardio-protective and anti-inflammatory properties of its natural counterparts. To address this question, we analyzed the ability of OMT-28 to ameliorate hypoxia/reoxygenation (HR)-injury and lipopolysaccharide (LPS)-induced endotoxemia in cultured cardiomyocytes. Moreover, we investigated the potential of OMT-28 to limit functional damage and inflammasome activation in isolated perfused mouse hearts subjected to ischemia/reperfusion (IR) injury. In the HR model, OMT-28 (1 μM) treatment largely preserved cell viability (about 75 vs. 40 % with vehicle) and mitochondrial function as indicated by the maintenance of NAD+/NADH-, ADP/ATP- and respiratory control ratios. Moreover, OMT-28 blocked the HR-induced production of mitochondrial reactive oxygen species. Pharmacological inhibition experiments suggested that Gαi, PI3K, PPARα, and Sirt1 are essential components of the OMT-28 mediated pro-survival pathway. Counteracting inflammatory injury of cardiomyocytes, OMT-28 (1 μM) reduced LPS-induced increases in TNFα protein (by about 85 % vs vehicle) and NF-κB DNA binding (by about 70 % vs. vehicle). In the ex vivo model, OMT-28 improved post-IR myocardial function recovery to reach about 40 % of the baseline value compared to less than 20 % with vehicle. Furthermore, OMT-28 (1 μM) limited IR-induced NLRP3 inflammasome activation similarly like a direct NLRP3 inhibitor (MCC950). Overall, this study demonstrates that OMT-28 possesses potent cardio-protective and anti-inflammatory properties supporting the hypothesis that extending the bioavailability of omega-3 epoxyeicosanoids may improve their prospects as therapeutic agents.

USF2 activates RhoB/ROCK pathway by transcriptional inhibition of miR-206 to promote pyroptosis in septic cardiomyocytes

Septic cardiomyopathy (SCM) is one of the most serious complications of sepsis. The present study investigated the role and mechanism of upstream stimulatory factor 2 (USF2) in SCM. Serum samples were extracted from SCM patients and healthy individuals. A murine model of sepsis was induced by caecal ligation and puncture (CLP) surgery. Myocardial injury was examined by echocardiography and HE staining. ELISA assay evaluated myocardial markers (CK-MB, cTnI) and inflammatory cytokines (TNF-α, IL-1β, IL-18). Primary mouse cardiomyocytes were treated with lipopolysaccharide (LPS) to simulate sepsis in vitro. RT-qPCR and Western blot were used for analyzing gene and protein levels. CCK-8 assay assessed cell viability. NLRP3 was detected by immunofluorescence. ChIP, RIP and dual luciferase reporter assays were conducted to validate the molecular associations. USF2 was increased in serum from SCM patients, septic mice and primary cardiomyocytes. USF2 silencing improved the survival of septic mice and attenuated sepsis-induced myocardial pyroptosis and inflammation in vitro and in vivo. Mechanistically, USF2 could directly bind to the promoter of miR-206 to transcriptionally inhibit its expression. Moreover, RhoB was confirmed as a target of miR-206 and could promote ROCK activation and NLRP3 inflammasome formation. Moreover, overexpression of RhoB remarkably reversed the protection against LPS-induced inflammation and pyroptosis mediated by USF2 deletion or miR-206 overexpression in cardiomyocytes. The above findings elucidated that USF2 knockdown exerted a cardioprotective effect on sepsis by decreasing pyroptosis and inflammation via miR-206/RhoB/ROCK pathway, suggesting that USF2 may be a novel drug target in SCM.

Activation of sigma-1 receptor ameliorates sepsis-induced myocardial injury by mediating the Nrf2/HO1 signaling pathway to attenuate mitochondrial oxidative stress

BACKGROUND

Sepsis is a condition that triggers the release of large amounts of reactive oxygen species and inflammatory factors in the body, leading to myocardial injury and cardiovascular dysfunction - an important contributor to the high mortality rate associated with sepsis. Although it has been demonstrated that the sigma-1 receptor (S1R) is essential for preventing oxidative stress, its effectiveness in treating sepsis is yet unknown.

AIM

This study aimed to investigate the role and mechanisms of S1R activation in sepsis-induced myocardial injury.

METHODS

A model of sepsis-induced myocardial injury was constructed by performing cecum ligation and puncture(CLP) surgery on rats. Flv or BD1047 were intraperitoneally injected into rats for one consecutive week before performing CLP, and then intraperitoneally injected into the rats again 1 h after the surgery.The effects of Flv and BD1047 were detected by HE staining, immunofluorescence staining, IHC staining, echocardiography measurements,TUNEL, oxidative stress detection, TEM, flow cytometry and western blot. We further validated the mechanism in vitro using neonatal rat cardiomyocites and H9C2 cells.

RESULTS

S1R protein level was reduced in the hearts of septic rats, whereas administration of Flv, an S1R activator, ameliorated myocardial injury, mitochondrial oxidative stress, and pathological manifestations of sepsis. On the other hand, administration of the S1R inhibitor BD1047 exacerbated the mitochondrial oxidative stress, and apoptosis, as well as symptoms and pathological manifestations of sepsis. In addition, we found that up-regulation of S1R activated the Nrf2/HO1 signaling pathway and promoted nuclear translocation of Nrf2, which activated downstream proteins to generate antioxidant factors, such as HO1, in turn alleviating oxidative stress and countering myocardial damage.

CONCLUSION

By scavenging ROS accumulation and reducing mitochondrial oxidative stress via the Nrf2/HO1 signaling pathway, activation of S1R improves cardiac function, mitigates death of cardiomyocytes, and attenuates sepsis-induced myocardial injury.

γ-Secretase inhibitor alleviates lipopolysaccharide-induced myocardial injury through regulating JAK2/STAT3 signaling

BACKGROUND

Septic myocardial injury is one of the most life-threatening organ dysfunction. The γ-secretase-based approaches have been developed as potential strategies for diverse diseases management. Unfortunately, the role of γ-secretase inhibitor in septic myocardial injury is unclarified. The present study aims to investigate the effect of γ-secretase inhibitor in septic myocardial injury and reveal its mechanism.

METHODS

The mouse model of septic myocardial injury was established by intraperitoneally injection of lipopolysaccharide (LPS), and γ-secretase inhibitor MW167 was applied in this model. RNA-sequencing analysis and further bioinformatics analyses were used to screen differential expressed genes (DEGs) and potentially enriched pathways between LPS and LPS + MW167 mice. Pathological examination was performed using haematoxylin and eosin (HE) staining. SD-1029 was used to block JAK2/STAT3 signaling in H9C2 cells and western blot analysis quantified JAK2/STAT3-related proteins.

RESULTS

LPS induced myocardial injury accompanied with significant inflammatory infiltration and more apoptotic cells. Transcriptome sequencing screened 36 DEGs and bioinformatics identified JAK2/STAT3 signaling pathway was significantly enriched. Further in vitro experiments showed that γ-secretase inhibitor MW167 activated JAK2/STAT3 pathway. Additionally, MW167 restored cell viability, decreased myocardial injury markers including cardiac troponin I (cTnI) and brain natriuretic peptide (BNP), inhibited pro-inflammatory cytokines such as interleukin (IL)-1β and tumor necrosis factor-α (TNF-α) and reduced nitric oxide (NO), cyclooxygenase-2 (COX2) and inducible nitric oxide synthase (iNOS) release. Application of SD-1029 reversely deteriorated LPS-induced myocardial injury and inflammatory response in γ-secretase inhibitor-treated myocardial cells.

CONCLUSION

The results demonstrate that γ-secretase inhibitor alleviates septic myocardial injury via activating JAK2/STAT3 signaling, and provide novel therapeutic direction for septic myocardial injury.

Emodin ameliorates doxorubicin-induced cardiotoxicity by inhibiting ferroptosis through the remodeling of gut microbiota composition

The relationship between gut microbiota and doxorubicin-induced cardiotoxicity (DIC) is becoming increasingly clear. Emodin (EMO), a naturally occurring anthraquinone, exerts cardioprotective effects and plays a protective role by regulating gut microbiota composition. Therefore, the protective effect of EMO against DIC injury and its underlying mechanisms are worth investigating. In this study, we analyzed the differences in the gut microbiota in recipient mice transplanted with different flora using 16S-rDNA sequencing, analyzed the differences in serum metabolites among groups of mice using a nontargeted gas chromatography-mass spectrometry coupling system, and assessed cardiac function based on cardiac morphological staining, cardiac injury markers, and ferroptosis indicator assays. We found EMO ameliorated DIC and ferroptosis, as evidenced by decreased myocardial fibrosis, cardiomyocyte hypertrophy, and myocardial disorganization; improved ferroptosis indicators; and the maintenance of normal mitochondrial morphology. The protective effect of EMO was eliminated by the scavenging effect of antibiotics on the gut microbiota. Through fecal microbiota transplantation (FMT), we found that EMO restored the gut microbiota disrupted by doxorubicin (DOX) to near-normal levels. This was evidenced by an increased proportion of Bacteroidota and a decreased proportion of Verrucomicrobiota. FMT resulted in changes in the composition of serum metabolites. Mice transplanted with EMO-improved gut microbiota showed better cardiac function and ferroptosis indices; however, these beneficial effects were not observed in Nrf2 (Nfe2l2)-/- mice. Overall, EMO exerted a protective effect against DIC by attenuating ferroptosis, and the above effects occurred by remodeling the composition of gut microbiota perturbed by DOX and required Nrf2 mediation.NEW & NOTEWORTHY This study demonstrated for the first time the protective effect of emodin against DIC and verified by FMT that its cardioprotective effect was achieved by remodeling gut microbiota composition, resulting in attenuation of ferroptosis. Furthermore, we demonstrated that these effects were mediated by the redox-related gene Nrf2.

ANXA1sp attenuates sepsis-induced myocardial injury by promoting mitochondrial biosynthesis and inhibiting oxidative stress and autophagy via SIRT3 upregulation

Sepsis-induced myocardial injury is one of the most difficult complications of sepsis in intensive care units. Annexin A1 (ANXA1) short peptide (ANXA1sp) protects organs during the perioperative period. However, the protective effect of ANXA1sp against sepsis-induced myocardial injury remains unclear. We aimed to explore the protective effects and mechanisms of ANXA1sp against sepsis-induced myocardial injury both in vitro and in vivo. Cellular and animal models of myocardial injury in sepsis were established with lipopolysaccharide. The cardiac function of mice was assessed by high-frequency echocardiography. Elisa assay detected changes in inflammatory mediators and markers of myocardial injury. Western blotting detected autophagy and mitochondrial biosynthesis-related proteins. Autophagic flux changes were observed by confocal microscopy, and autophagosomes were evaluated by TEM. ATP, SOD, ROS, and MDA levels were also detected.ANXA1sp pretreatment enhanced the 7-day survival rate, improved cardiac function, and reduced TNF-α, IL-6, IL-1β, CK-MB, cTnI, and LDH levels. ANXA1sp significantly increased the expression of sirtuin-3 (SIRT3), mitochondrial biosynthesis-related proteins peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α), and mitochondrial transcription factor A (TFAM). ANXA1sp increased mitochondrial membrane potential (△Ψm), ATP, and SOD, and decreased ROS, autophagy flux, the production of autophagosomes per unit area, and MDA levels. The protective effect of ANXA1sp decreased significantly after SIRT3 silencing in vitro and in vivo, indicating that the key factor in ANXA1sp's protective role is the upregulation of SIRT3. In summary, ANXA1sp attenuated sepsis-induced myocardial injury by upregulating SIRT3 to promote mitochondrial biosynthesis and inhibit oxidative stress and autophagy.

Chicoric acid ameliorates sepsis-induced cardiomyopathy via regulating macrophage metabolism reprogramming

BACKGROUND

Sepsis-related cardiac dysfunction is believed to be a primary cause of high morbidity and mortality. Metabolic reprogramming is closely linked to NLRP3 inflammasome activation and dysregulated glycolysis in activated macrophages, leading to inflammatory responses in septic cardiomyopathy. Succinate dehydrogenase (SDH) and succinate play critical roles in the progression of metabolic reprogramming in macrophages. Inhibition of SDH may be postulated as an effective strategy to attenuate macrophage activation and sepsis-induced cardiac injury.

PURPOSE

This investigation was designed to examine the role of potential compounds that target SDH in septic cardiomyopathy and the underlying mechanisms involved.

METHODS/RESULTS

From a small molecule pool containing about 179 phenolic compounds, we found that chicoric acid (CA) had the strongest ability to inhibit SDH activity in macrophages. Lipopolysaccharide (LPS) exposure stimulated SDH activity, succinate accumulation and superoxide anion production, promoted mitochondrial dysfunction, and induced the expression of hypoxia-inducible factor-1α (HIF-1α) in macrophages, while CA ameliorated these changes. CA pretreatment reduced glycolysis by elevating the NAD+/NADH ratio in activated macrophages. In addition, CA promoted the dissociation of K(lysine) acetyltransferase 2A (KAT2A) from α-tubulin, and thus reducing α-tubulin acetylation, a critical event in the assembly and activation of NLRP3 inflammasome. Overexpression of KAT2A neutralized the effects of CA, indicating that CA inactivated NLRP3 inflammasome in a specific manner that depended on KAT2A inhibition. Importantly, CA protected the heart against endotoxin insult and improved sepsis-induced cardiac mitochondrial structure and function disruption. Collectively, CA downregulated HIF-1α expression via SDH inactivation and glycolysis downregulation in macrophages, leading to NLRP3 inflammasome inactivation and the improvement of sepsis-induced myocardial injury.

CONCLUSION

These results highlight the therapeutic role of CA in the resolution of sepsis-induced cardiac inflammation.

Current insight on the mechanisms of programmed cell death in sepsis-induced myocardial dysfunction

Sepsis is a clinical syndrome characterized by a dysregulated host response to infection, leading to life-threatening organ dysfunction. It is a high-fatality condition associated with a complex interplay of immune and inflammatory responses that can cause severe harm to vital organs. Sepsis-induced myocardial injury (SIMI), as a severe complication of sepsis, significantly affects the prognosis of septic patients and shortens their survival time. For the sake of better administrating hospitalized patients with sepsis, it is necessary to understand the specific mechanisms of SIMI. To date, multiple studies have shown that programmed cell death (PCD) may play an essential role in myocardial injury in sepsis, offering new strategies and insights for the therapeutic aspects of SIMI. This review aims to elucidate the role of cardiomyocyte's programmed death in the pathophysiological mechanisms of SIMI, with a particular focus on the classical pathways, key molecules, and signaling transduction of PCD. It will explore the role of the cross-interaction between different patterns of PCD in SIMI, providing a new theoretical basis for multi-target treatments for SIMI.

Emodin attenuates cardiomyocyte pyroptosis in doxorubicin-induced cardiotoxicity by directly binding to GSDMD

BACKGROUND

Doxorubicin (Dox), which is an anticancer drug, has significant cardiac toxicity and side effects. Pyroptosis occurs during Dox-induced cardiotoxicity (DIC), and drug inhibition of this process is one therapeutic approach for treating DIC. Previous studies have indicated that emodin can reduce pyroptosis. However, the role of emodin in DIC and its molecular targets remain unknown.

HYPOTHESIS/PURPOSE

We aimed to clarify the protective role of emodin in mitigating DIC, as well as the mechanisms underlying this effect.

METHODS

The model of DIC was established via the intraperitoneal administration of Dox at a dosage of 5 mg/kg per week for a span of 4 weeks. Emodin at two different doses (10 and 20 mg/kg) or a vehicle was intragastrically administered to the mice once per day throughout the Dox treatment period. Cardiac function, myocardial injury markers, pathological morphology of the heart, level of pyroptosis and mitochondrial function were assessed. Protein microarray, biolayer interferometry and pull-down assays were used to confirm the target of emodin. Moreover, GSDMD-overexpressing plasmids were transfected into GSDMD-/- mice and HL-1 cells to further verify whether emodin suppressed GSDMD activation.

RESULTS

Emodin therapy markedly enhanced cardiac function and reduced cardiomyocyte pyroptosis in mice induced by Dox. Mechanistically, emodin binds to GSDMD and inhibits the activation of GSDMD by targeting the Trp415 and Leu290 residues. Moreover, emodin was able to mitigate Dox-induced cardiac dysfunction and myocardial injury in GSDMD-/- mice overexpressing GSDMD, as shown by increased EF and FS, decreased serum levels of CK-MB, LDH and IL-1β and mitigated cell death and cell morphological disorder. Additionally, emodin treatment significantly reduced GSDMD-N expression and plasma membrane disruption in HL-1 cells overexpressing GSDMD induced by Dox. In addition, emodin reduced mitochondrial damage by alleviating Dox-induced GSDMD perforation in the mitochondrial membrane.

CONCLUSION

Emodin has the potential to attenuate DIC by directly binding to GSDMD to inhibit pyroptosis. Emodin may become a promising drug for prevention and treatment of DIC.

Emodin ameliorates matrix degradation and apoptosis in nucleus pulposus cells and attenuates intervertebral disc degeneration through LRP1 in vitro and in vivo

Low back pain (LBP) is the leading cause of disability worldwide, with a strong correlation to intervertebral disc degeneration (IDD). Inflammation-induced extracellular matrix (ECM) degradation plays a major role in IDD's progression. Emodin, known for its anti-inflammatory effects and ability to inhibit ECM degradation in osteoarthritis, but its role in IDD is unclear. Our study aimed to explore emodin's role and mechanisms on IDD both in vivo and in vitro. We discovered that emodin positively regulated anabolic markers (COL2A1, aggrecan) and negatively impacted catabolic markers (MMP3, MMP13) in nucleus pulposus cells, while also inhibiting cell apoptosis under inflammation environment. We revealed that emodin inhibits inflammation-induced NF-ĸB activation by suppressing the degradation of LRP1 via the proteasome pathway. Additionally, LRP1 was validated as essential to emodin's regulation of ECM metabolism and apoptosis, both in vitro and in vivo. Ultimately, we demonstrated that emodin effectively alleviates IDD in a rat model. Our findings uncover the novel pathway of emodin inhibiting ECM degradation and apoptosis through the inhibition of NF-κB via LRP1, thus alleviating IDD. This study not only broadens our understanding of emodin's role and mechanism in IDD treatment but also guides future therapeutic interventions.

Recent Progress and Prospects of Small Molecules for NLRP3 Inflammasome Inhibition

NLRP3 inflammasome is a multiprotein complex involved in host immune response─which exerts various biological effects by mediating the maturation and secretion of IL-1β and IL-18─and pyroptosis. However, its aberrant activation could cause amplification of inflammatory effects, thereby triggering a range of ailments, including Alzheimer's disease, Parkinson's disease, rheumatoid arthritis, gout, type 2 diabetes mellitus, and cancer. For the past few years, as an attractive anti-inflammatory target, NLRP3-targeting small-molecule inhibitors have been widely reported by both the academic and the industrial communities. In order to deeply understand the advancement of NLRP3 inflammasome inhibitors, we provide comprehensive insights and commentary on drugs currently under clinical investigation, as well as other NLRP3 inflammasome inhibitors from a chemical structure point of view, with an aim to provide new insights for the further development of clinical drugs for NLRP3 inflammasome-mediated diseases.

Role of toll-like receptor-mediated pyroptosis in sepsis-induced cardiomyopathy

Sepsis, a life-threatening dysregulated status of the host response to infection, can cause multiorgan dysfunction and mortality. Sepsis places a heavy burden on the cardiovascular system due to the pathological imbalance of hyperinflammation and immune suppression. Myocardial injury and cardiac dysfunction caused by the aberrant host responses to pathogens can lead to cardiomyopathy, one of the most critical complications of sepsis. However, many questions about the specific mechanisms and characteristics of this complication remain to be answered. The causes of sepsis-induced cardiac dysfunction include abnormal cardiac perfusion, myocardial inhibitory substances, autonomic dysfunction, mitochondrial dysfunction, and calcium homeostasis dysregulation. The fight between the host and pathogens acts as the trigger for sepsis-induced cardiomyopathy. Pyroptosis, a form of programmed cell death, plays a critical role in the progress of sepsis. Toll-like receptors (TLRs) act as pattern recognition receptors and participate in innate immune pathways that recognize damage-associated molecular patterns as well as pathogen-associated molecular patterns to mediate pyroptosis. Notably, pyroptosis is tightly associated with cardiac dysfunction in sepsis and septic shock. In line with these observations, induction of TLR-mediated pyroptosis may be a promising therapeutic approach to treat sepsis-induced cardiomyopathy. This review focuses on the potential roles of TLR-mediated pyroptosis in sepsis-induced cardiomyopathy, to shed light on this promising therapeutic approach, thus helping to prevent and control septic shock caused by cardiovascular disorders and improve the prognosis of sepsis patients.

NLRP3 inflammasome involves in the pathophysiology of sepsis-induced myocardial dysfunction by multiple mechanisms

Sepsis-induced myocardial dysfunction (SIMD) is one of the serious health-affecting problems worldwide. At present, the mechanisms of SIMD are still not clearly elucidated. The NOD-like receptor protein 3 (NLRP3) inflammasome has been assumed to be involved in the pathophysiology of SIMD by regulating multiple biological processes. NLRP3 inflammasome and its related signaling pathways might affect the regulation of inflammation, autophagy, apoptosis, and pyroptosis in SIMD. A few molecular specific inhibitors of NLRP3 inflammasome (e.g., Melatonin, Ulinastatin, Irisin, Nifuroxazide, and Ginsenoside Rg1, etc.) have been developed, which showed a promising anti-inflammatory effect in a cellular or animal model of SIMD. These experimental findings indicated that NLRP3 inflammasome could be a promising therapeutic target for SIMD treatment. However, the clinical translation of NLRP3 inhibitors for treating SIMD still requires robust in vivo and preclinical trials.

Potential biomarker for diagnosis and therapy of sepsis: Lactylation

INTRODUCTION

As a disease that has plagued human health for decades, sepsis has so far had no specific diagnostic or therapeutic indicators. The discovery of lactylation modifications not only uncovered the deep-rooted causes of changing between lactate level and pathophysiology and immunology of sepsis, but also reaffirmed the inevitable link between metabolic reprogramming and epigenetic reprogramming in sepsis. Lactylation modification became a potential marker for diagnosis and guiding the treatment of sepsis.

AIM

In this paper, we will summarize the discovery and regulation of lactylation modifications, discuss the study of lactylation modifications in sepsis, and evaluate their possibility and potential as diagnostic and therapeutic indicators of sepsis.

CONCLUSION

Lactylation modification is directly regulated by glycolysis and lactate, and inhibition of glycolytic pathway-related enzymes can regulate the level of lactylation modification, and more importantly, lactylation modification can act on these enzymes to regulate their functions and feedback regulate the level of glycolysis, this finding provides more ideas for clinical treatment of sepsis. We use "epigenetic modification", "glycolysis", "lactate", "lactylaiton" and "sepsis" as keywords and search the relevant literature through Pubmed and Web of science up to 2023.

Bacterial lipopolysaccharide-induced endothelial activation and dysfunction: a new predictive and therapeutic paradigm for sepsis

BACKGROUND

Lipopolysaccharide, a highly potent endotoxin responsible for severe sepsis, is the major constituent of the outer membrane of gram-negative bacteria. Endothelial cells participate in both innate and adaptive immune responses as the first cell types to detect lipopolysaccharide or other foreign debris in the bloodstream. Endothelial cells are able to recognize the presence of LPS and recruit specific adaptor proteins to the membrane domains of TLR4, thereby initiating an intracellular signaling cascade. However, lipopolysaccharide binding to endothelial cells induces endothelial activation and even damage, manifested by the expression of proinflammatory cytokines and adhesion molecules that lead to sepsis.

MAIN FINDINGS

LPS is involved in both local and systemic inflammation, activating both innate and adaptive immunity. Translocation of lipopolysaccharide into the circulation causes endotoxemia. Endothelial dysfunction, including exaggerated inflammation, coagulopathy and vascular leakage, may play a central role in the dysregulated host response and pathogenesis of sepsis. By discussing the many strategies used to treat sepsis, this review attempts to provide an overview of how lipopolysaccharide induces the ever more complex syndrome of sepsis and the potential for the development of novel sepsis therapeutics.

CONCLUSIONS

To reduce patient morbidity and mortality, preservation of endothelial function would be central to the management of sepsis.

Focal adhesion kinase induces cardiac remodeling through NF-κB-mediated inflammatory responses in diabetic cardiomyopathy

BACKGROUND

Hyperglycemia-induced chronic inflammation is a crucial risk factor that causes undesirable cardiac alternations in diabetic cardiomyopathy (DCM). Focal adhesion kinase (FAK) is a non-receptor protein tyrosine kinase that primarily regulates cell adhesion and migration. Based on recent studies, FAK is involved in inflammatory signaling pathway activation in cardiovascular diseases. Here, we evaluated the possibility of FAK as a therapeutic target for DCM.

METHODS

A small molecular selective FAKinhibitor, PND-1186 (PND), was used to evaluate the effect of FAK on DCM in both high glucose-stimulated cardiomyocytes and streptozotocin (STZ)-induced type 1 diabetes mellitus (T1DM) mice.

RESULTS

Increased FAK phosphorylation was found in the hearts of STZ-induced T1DM mice. PND treatment significantly decreased the expression of inflammatory cytokines and fibrogenic markers in cardiac specimens of diabetic mice. Notably, these reductions were correlated with improved cardiac systolic function. Furthermore, PND suppressed transforming growth factor-β-activated kinase 1 (TAK1) phosphorylation and NF-κB activation in the hearts of diabetic mice. Cardiomyocytes were identified as the main contributor to FAK-mediated cardiac inflammation and the involvement of FAK in cultured primary mouse cardiomyocytes and H9c2 cells was identified. Both FAK inhibition or FAK deficiency prevented hyperglycemia-induced inflammatory and fibrotic responses in cardiomyocytes owing to the inhibition of NF-κB. Herein, FAK activation was revealed to FAK directly binding to TAK1, leading to activation of TAK1 and downstream NF-κB signaling pathway.

CONCLUSIONS

FAK is a key regulator of diabetes-associated myocardial inflammatory injury by directly targeting to TAK1.

Role of emodin in atherosclerosis and other cardiovascular diseases: Pharmacological effects, mechanisms, and potential therapeutic target as a phytochemical

The morbidity and mortality of cardiovascular diseases (CVDs) are increasing in recent years, and atherosclerosis (AS), a major CVD, becomes a disorder that afflicts human beings severely, especially the elders. AS is recognized as the primary cause and pathological basis of some other CVDs. The active constituents of Chinese herbal medicines have garnered increasing interest in recent researches owing to their influence on AS and other CVDs. Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is a naturally occurring anthraquinone derivative found in some Chinese herbal medicines such as Rhei radix et rhizome, Polygoni cuspidati rhizoma et radix and Polygoni multiflori root. In this paper, we first review the latest researches about emodin's pharmacology, metabolism and toxicity. Meanwhile, it has been shown to be effective in treating CVDs caused by AS in dozens of previous studies. Therefore, we systematically reviewed the mechanisms by which emodin treats AS. In summary, these mechanisms include anti-inflammatory activity, lipid metabolism regulation, anti-oxidative stress, anti-apoptosis and vascular protection. The mechanisms of emodin in other CVDs are also discussed, such as vasodilation, inhibition of myocardial fibrosis, inhibition of cardiac valve calcification and antiviral properties. We have further summarized the potential clinical applications of emodin. Through this review, we hope to provide guidance for clinical and preclinical drug development.

Emodin alleviates lung ischemia-reperfusion injury by suppressing gasdermin D-mediated pyroptosis in rats

BACKGROUND

Pyroptosis refers to programmed cell death associated with inflammation. Emodin has been reported to alleviate lung injuries caused by various pathological processes and attenuate ischemia-reperfusion (I/R) injuries in diverse tissues.

METHODS

Lewis rats were assigned into the sham, the I/R, and the I/R + emodin groups. Emodin and phosphate-buffered saline were intraperitoneally injected into rats of the emodin group and I/R group for 30 min, respectively. These rats were then subjected to left thoracotomy followed by 90-min clamping of the left hilum and 120-min reperfusion. Sham-operated rats underwent 210-min ventilation. Lung functions, histological changes, lung edema, and cytokine levels were assessed. Protein levels were measured by western blotting. Immunofluorescence staining was conducted to evaluate pyroptosis.

RESULTS

Emodin alleviated the I/R-induced lung dysfunction, lung damages, and inflammation. Protective effects of emodin against I/R-mediated endothelial pyroptosis was observed in vivo and in vitro. Mechanistically, emodin inactivated the TLR4/MyD88/NF-κB/NLRP3 pathway.

CONCLUSION

Emodin attenuates lung ischemia-reperfusion injury by inhibiting GSDMD-mediated pyroptosis in rats.

Emodin Regulates lncRNA XIST/miR-217 Axis to Protect Myocardial Ischemia-Reperfusion Injury

Purpose

This study is aimed at investigating the effect of emodin on myocardial ischemia-reperfusion injury (MIRI) and mechanism.

Methods

Eighty healthy adult male SD rats (weighing 230-250 g) were utilized to establish I/R model, which were randomly divided into five groups (16 rats in each group): sham operation group, myocardial ischemia-reperfusion injury group (I/R group), emodin group, emodin +NC group, and emodin +XIST group. The contents of CK, CK-MB, LDH, and HBDH in serum were determined by ELISA kit. LDH was detected by ELISA assay, SOD was detected by the xanthine oxidase method, and MDA was detected by the thiobarbituric acid method. The relative expression of XIST and miR-217 was evaluated by RT-qPCR. Western blot was applied to detect the protein expression. Flow cytometry was applied to detect cardiomyocyte apoptosis.

Results

Myocardial infarction area was obviously increased in I/R model rats, while emodin decreased the myocardial infarction in I/R model rats. In addition, cardiac enzymes (CK, CK-MB, LDH, and HBDH) and apoptosis were obviously increased in MIRI model rats, while emodin obviously decreased cardiac enzymes and apoptosis. The ROS and MDA levels were raised while the activities of SOD were declined in the I/R model group. The ROS and MDA levels were decreased while the activities of SOD were raised in the emodin group. The XIST expression was markedly raised in the I/R model group while decreased in the emodin group, and the overexpression of XIST reversed the protective effect of emodin on myocardial infarction, oxidative stress, and cardiomyocyte apoptosis. In addition, XIST directly regulated the expression of miR-217, and si-XIST inhibited H/R-induced oxidative damage of cardiomyocytes via inhibiting miR-217.

Conclusion

Emodin protected MIRI both in vitro and in vivo via inhibiting lncRNA XIST to upregulate miR-217.

Traditional Chinese medicine for treatment of sepsis and related multi-organ injury

Sepsis is a common but critical illness in patients admitted to the intensive care unit and is associated with high mortality. Although there are many treatments for sepsis, specific and effective therapies are still lacking. For over 2,000 years, traditional Chinese medicine (TCM) has played a vital role in the treatment of infectious diseases in Eastern countries. Both anecdotal and scientific evidence show that diverse TCM preparations alleviate organ dysfunction caused by sepsis by inhibiting the inflammatory response, reducing oxidative stress, boosting immunity, and maintaining cellular homeostasis. This review reports on the efficacy and mechanism of action of various TCM compounds, herbal monomer extracts, and acupuncture, on the treatment of sepsis and related multi-organ injury. We hope that this information would be helpful to better understand the theoretical basis and empirical support for TCM in the treatment of sepsis.

Mild Hypothermia Alleviates CLP-induced Multiple Organ Dysfunction by Mitigating Pyroptosis Through the TLR4/NF-κB/NLRP3 Signaling Pathway

BACKGROUND

Multiple organ failure secondary to severe sepsis leads to increased morbidity and mortality and is often accompanied by inflammation and immune system dysfunction. Mild hypothermia has been shown to have anti-inflammatory properties, but whether it can exert a protective effect in cases of multiple organ failure remains unclear. Thus, in this study, we investigated the protective effect of mild hypothermia on septic multiple organ failure and the underlying mechanism for this effect.

METHOD

Sepsis was induced through the cecal ligation and puncture (CLP) method. Rats were then housed at normal (36-38°C) or mild hypothermic (32-34°C) temperature for 10 h.

RESULTS

CLP-induced effects on inflammatory cytokines and biochemical markers in serum were reversed by mild hypothermia. The pathological injury score and the expressions of pyroptosis markers, including TLR4, MyD88 and NF-κB signaling molecules, showed a similar trend. Moreover, 3 d survival of CLP rats was improved by mild hypothermia.

CONCLUSIONS

Mild hypothermia alleviated CLP-induced organ failure and the downstream effects on pyroptosis, probably through the TLR4/NF-κB/NLRP3 signaling pathway.

Inhibition of TAK1/TAB2 complex formation by costunolide attenuates obesity cardiomyopathy via the NF-κB signaling pathway

BACKGROUND

Chronic and persistent obesity can lead to various complications, including obesity cardiomyopathy. Inhibition of the inflammatory response is an effective measure for the intervention of obesity cardiomyopathy. Numerous studies indicate that costunolide (Cos) can reduce inflammation. However, the role of Cos in obesity cardiomyopathy and its molecular targets remains unknown.

HYPOTHESIS/PURPOSE

We aimed to clarify potential cardioprotective effects and mechanism of Cos against obesity cardiomyopathy.

METHODS

The model of obesity cardiomyopathy was established by feeding mice with a high-fat diet for 24 weeks. Cos at 10 and 20 mg/kg or vehicle (1% CMCNa solution) was administered once every two days via oral gavage from the 17th to 24th week. Body weight, heart weight/tibia length, cardiac function, myocardial injury markers, pathological morphology of the heart, hypertrophic and fibrotic markers, inflammatory factors were assessed. The targets of Cos were predicted through molecular docking. Pull-down assay and biolayer interferometry were used to confirm the target of Cos.

RESULTS

Cos effectively reduces obesity-induced cardiomyocyte inflammation, cardiac hypertrophy and fibrosis, thereby improving cardiac function. We confirmed that Cos can interact with TAK1 and inhibit downstream NF-κB pathway activation by blocking the formation of the TAK1/TAB2 complex, thus inhibiting inflammatory cytokine release in cardiomyocytes.

CONCLUSION

Our results demonstrated that Cos significantly improved myocardial remodeling and cardiac dysfunction against obesity cardiomyopathy by reducing myocardial inflammation. Therefore, Cos may serve as a promising therapeutic agent in obesity cardiomyopathy.

Emodin in cardiovascular disease: The role and therapeutic potential

Emodin is a natural anthraquinone derivative extracted from Chinese herbs, such as Rheum palmatum L, Polygonum cuspidatum, and Polygonum multiflorum. It is now also a commonly used clinical drug and is listed in the Chinese Pharmacopoeia. Emodin has a wide range of pharmacological properties, including anticancer, antiinflammatory, antioxidant, and antibacterial effects. Many in vivo and in vitro experiments have demonstrated that emodin has potent anticardiovascular activity. Emodin exerts different mechanisms of action in different types of cardiovascular diseases, including its involvement in pathological processes, such as inflammatory response, apoptosis, cardiac hypertrophy, myocardial fibrosis, oxidative damage, and smooth muscle cell proliferation. Therefore, emodin can be used as a therapeutic drug against cardiovascular disease and has broad application prospects. This paper summarized the main pharmacological effects and related mechanisms of emodin in cardiovascular diseases in recent years and discussed the limitations of emodin in terms of extraction preparation, toxicity, and bioavailability-related pharmacokinetics in clinical applications.

Vitamin C alleviates LPS-induced myocardial injury by inhibiting pyroptosis via the ROS-AKT/mTOR signalling pathway

BACKGROUND

The efficacy of vitamin C in sepsis remains controversial. Whether vitamin C can alleviate lipopolysaccharide (LPS)-induced myocardial injury by inhibiting pyroptosis has not been studied. This study aimed to evaluate the effects of vitamin C on LPS-induced myocardial injury in vitro.

METHODS

H9C2 cells were treated with indicated concentrations of LPS, and the cell viability was then assessed by CCK-8 assay. The levels of lactate dehydrogenase (LDH), CK-MB, IL-18 and IL-1β were examined by enzyme-linked immunosorbent assay (ELISA). The levels of intracellular reactive oxygen species (ROS) were measured using the fluorescent probe dichlorodihydrofluorescein diacetate (DCFH-DA). Western blot assays were conducted to determine the levels of the ROS-associated protein nicotinamide adenine dinucleotide phosphate oxidase 4 (Nox4) and pyroptosis-associated proteins, such as NOD-like receptor (NLR) family pyrin domain containing 3 (NLRP3), caspase-1 and gasdermin D (GSDMD). The AKT inhibitor MK-2206 was then applied to explore the signalling pathway. Finally, H9C2 cells were divided into the control group, LPS group, vitamin C + LPS group, and N-acetyl-L-cysteine (NAC) + LPS group. The intracellular ROS, levels of associated proteins, cell viability, and release of LDH, CK-MB, IL-18 and IL-1β were examined.

RESULTS

LPS decreased cell viability and induced ROS and pyroptosis in H9C2 cells in a dose-dependent manner. Moreover, LPS activated the AKT/mTOR pathway in H9C2 cells. The AKT inhibitor MK-2206 protected H9C2 cells from LPS-induced death by suppressing pyroptosis, without changing intracellular ROS level. Vitamin C significantly inhibited intracellular ROS and cell pyroptosis in LPS-treated H9C2 cells. Moreover, vitamin C suppressed the activation of the AKT/mTOR pathway.

CONCLUSIONS

Our data suggest that vitamin C alleviates LPS-induced myocardial injury by inhibiting pyroptosis via the ROS-AKT/mTOR signalling pathway and thus provide novel insights into the prevention of sepsis-induced myocardial dysfunction.

Platelet-rich plasma ameliorates lipopolysaccharide-induced cardiac injury by inflammation and ferroptosis regulation

Sepsis-induced myocardial dysfunction (SIMD) is a fatal disease with no specific treatment worldwide to this day. As a biological product, platelet-rich plasma (PRP) has attracted much attention due to its diverse and potential biological effects. However, its role in lipopolysaccharide (LPS)-induced cardiac injury has not been fully investigated. This study aimed to explore the mechanism of PRP in SIMD. PRP (30 µL) was injected in situ into the heart, and LPS (10 mg/kg) was injected intraperitoneally into mice. Neonatal rat cardiomyocytes were treated with LPS (1 μg/ml) for 24 h. The results showed that, compared with the LPS group, PRP significantly decreased the levels of Lactate dehydrogenase (LDH) and Creatine Kinase MB (CK-MB), and improved cardiac function. In addition, PRP markedly decreased the Malonic dialdehyde (MDA) content, and increased the Superoxide dismutase (SOD) activity and Glutathione (GSH) level, demonstrating that PRP alleviated LPS-induced oxidative stress. The Western blot and qPCR results showed that LPS-induced ferroptosis and inflammation effects in vivo and in vitro were ameliorated after PRP treatment. Moreover, PRP can alleviate erastin-induced ferroptosis and improve cell viability. Mechanistically, p-AKT and p-mTOR expressions were down-regulated after treatment with LPS, while PRP pretreatment could reverse this effect. In summary, our study demonstrated that PRP could play a unique role in reducing LPS-induced cardiac injury through regulation of AKT/mTOR signaling pathways. These findings provide a new therapeutic direction for treating SIMD.

Gasdermin D mediates doxorubicin-induced cardiomyocyte pyroptosis and cardiotoxicity via directly binding to doxorubicin and changes in mitochondrial damage

Doxorubicin (Dox), as a widely used anthracycline antitumor drug, can cause severe cardiotoxicity. Cardiomyocyte death and inflammation are involved in the pathophysiology of Dox-induced cardiotoxicity (DIC). Gasdermin D (GSDMD) is known as a key executioner of pyroptosis, which is a pro-inflammatory programmed cell death. We aimed to investigate the impact of GSDMD on DIC and systematically reveal its underlying mechanisms. Our findings indicated that Dox induced cardiomyocyte pyroptosis in a GSDMD-dependent manner by utilizing siRNA or overexpression-plasmid technique. We then generated GSDMD global knockout mice via CRISPR/Cas9 system and found that GSDMD deficiency reduced Dox-induced cardiomyopathy. Dox induced the activation of inflammatory caspases, which subsequently mediated GSDMD-N generation indirectly. Using molecular dynamics simulation and cell-free systems, we confirmed that Dox directly bound to GSDMD and facilitated GSDMD-N-mediated pyroptosis. Furthermore, GSDMD also mediated Dox-induced mitochondrial damage via Bnip3 and mitochondrial perforation in cardiomyocytes. These findings provide fresh insights into the mechanism of how Dox-engaged GSDMD orchestrates adverse cardiotoxicity and highlight the prospects of GSDMD as a potential target for DIC.

Traditional Chinese Medicine: A promising strategy to regulate inflammation, intestinal disorders and impaired immune function due to sepsis

Sepsis is described as a dysregulation of the immune response to infection, which leads to life-threatening organ dysfunction. The interaction between intestinal microbiota and sepsis can’t be ignored. Furthermore, the intestinal microbiota may regulate the progress of sepsis and attenuate organ damage. Thus, maintaining or restoring microbiota may be a new way to treat sepsis. Traditional Chinese medicine (TCM) assumes a significant part in the treatment of sepsis through multi-component, multi-pathway, and multi-targeting abilities. Moreover, TCM can prevent the progress of sepsis and improve the prognosis of patients with sepsis by improving the imbalance of intestinal microbiota, improving immunity and reducing the damage to the intestinal barrier. This paper expounds the interaction between intestinal microbiota and sepsis, then reviews the current research on the treatment of sepsis with TCM, to provide a theoretical basis for its clinical application.

Sennoside A is a novel inhibitor targeting caspase-1

The assembly of inflammasomes drives caspase-1 activation, which further promotes proinflammatory cytokine secretion and downstream pyroptosis. The discovery of novel caspase-1 inhibitors is pivotal to developing new therapeutic means for inflammasome-involved diseases. In our present study, sennoside A (Sen A), a popular ingredient in multiple weight-loss medicines and dietary supplements, is found to potently inhibit the enzymatic activity of caspase-1 in vitro. Sen A considerably decreased IL-1β production in macrophages stimulated by LPS plus ATP, nigericin or MSU as well as poly(dA:dT) transfection, and remedied ROS-involved pyroptosis via caspase-1 inhibition. Mechanistically, Sen A not only suppressed the assembly of both NLRP3 and AIM2 inflammasome but also affected the priming process of NLRP3 inflammasome by blocking NF-κB signaling. Sen A significantly ameliorated the pathophysiological effect in LPS-, MSU- and carrageenan-challenged rodent models by suppressing inflammasome activation. Furthermore, P2X7 was indispensable for Sen A inhibiting NLRP3 inflammasome since it failed to further decrease IL-1β and IL-18 production in LPS plus ATP-stimulated BMDMs that were transfected with P2X7 siRNA. Sen A also restrained the large pore-forming functionalities of the P2X7R as verified by the YO-PRO-1 uptake assay. Taken together, Sen A inactivates caspase-1 to inhibit NLRP3 and AIM2 inflammasome-involved inflammation in a P2X7-dependent manner, making it an attractive candidate as a caspase-1 small-molecular inhibitor.

The NLRP3 Inflammasome as a Novel Therapeutic Target for Cardiac Fibrosis

Cardiac fibrosis often has adverse cardiovascular effects, including heart failure, sudden death, and malignant arrhythmias. However, there is no targeted therapy for cardiac fibrosis. Inflammation is known to play a crucial role in the disorder, and the NLR pyrin domain-containing-3 (NLRP3) inflammasome is closely associated with innate immunity. Therefore, further understanding the pathophysiological role of the inflammasome in cardiac fibrosis may provide novel strategies for the prevention and treatment of the disorder. The aim of this review was to summarize the present knowledge of NLRP3 inflammasome-related mechanisms underlying cardiac fibrosis and to suggest potential targeted therapy that could be used to treat the condition.

Research Progress on the Mechanism of Sepsis Induced Myocardial Injury

Sepsis is an abnormal condition with multiple organ dysfunctions caused by the uncontrolled infection response and one of the major diseases that seriously hang over global human health. Besides, sepsis is characterized by high morbidity and mortality, especially in intensive care unit (ICU). Among the numerous subsequent organ injuries of sepsis, myocardial injury is one of the most common complications and the main cause of death in septic patients. To better manage septic inpatients, it is necessary to understand the specific mechanisms of sepsis induced myocardial injury (SIMI). Therefore, this review will elucidate the pathophysiology of SIMI from the following certain mechanisms: apoptosis, mitochondrial damage, autophagy, excessive inflammatory response, oxidative stress and pyroptosis, and outline current therapeutic strategies and potential approaches in SIMI.

Emodin Ameliorates Acute Pancreatitis-Associated Lung Injury Through Inhibiting the Alveolar Macrophages Pyroptosis

Objective: To investigate the protective effect of emodin in acute pancreatitis (AP)-associated lung injury and the underlying mechanisms. Methods: NaT-AP model in rats was constructed using 3.5% sodium taurocholate, and CER+LPS-AP model in mice was constructed using caerulein combined with Lipopolysaccharide. Animals were divided randomly into four groups: sham, AP, Ac-YVAD-CMK (caspase-1 specific inhibitor, AYC), and emodin groups. AP-associated lung injury was assessed with H&E staining, inflammatory cytokine levels, and myeloperoxidase activity. Alveolar macrophages (AMs) pyroptosis was evaluated by flow cytometry. In bronchoalveolar lavage fluid, the levels of lactate dehydrogenase and inflammatory cytokines were measured by enzyme-linked immunosorbent assay. Pyroptosis-related protein expressions were detected by Western Blot. Results: Emodin, similar to the positive control AYC, significantly alleviated pancreas and lung damage in rats and mice. Additionally, emodin mitigated the pyroptotic process of AMs by decreasing the level of inflammatory cytokines and lactate dehydrogenase. More importantly, the protein expressions of NLRP3, ASC, Caspase1 p10, GSDMD, and GSDMD-NT in AMs were significantly downregulated after emodin intervention. Conclusion: Emodin has a therapeutic effect on AP-associated lung injury, which may result from the inhibition of NLRP3/Caspase1/GSDMD-mediated AMs pyroptosis signaling pathways.

Red Blood Cell Membrane-Camouflaged PLGA Nanoparticles Loaded With Basic Fibroblast Growth Factor for Attenuating Sepsis-Induced Cardiac Injury

Cardiac injury is recognized as a major contributor to septic shock and a major component of the multiple organ dysfunction associated with sepsis. Emerging evidence shows that regulation of the intramyocardial oxidative stress and inflammatory response has a promising prospect. Basic fibroblast growth factor (bFGF) exhibits anti-inflammatory and antioxidant properties. In this study, red blood cell membrane-camouflaged poly (lactide-co-glycolide) nanoparticles were synthesized to deliver bFGF (bFGF-RBC/NP) for sepsis-induced cardiac injury. The in vitro experiments revealed that bFGF-RBC/NP could protect cardiomyocytes from oxidative and inflammatory damage. In addition, the antioxidant and anti-inflammatory properties of bFGF-RBC/NP against cardiac injury were validated using data from in vivo experiments. Collectively, our study used bFGF for the treatment of sepsis-induced cardiac injury and confirmed that bFGF-RBC/NP has therapeutic benefits in the treatment of myocardial dysfunction. This study provides a novel strategy for preventing and treating cardiac injury in sepsis.

MiR-501-5p alleviates cardiac dysfunction in septic patients through targeting NR4A3 to prevent its binding with Bcl-2

Sepsis-induced myocardial dysfunction is a common complication in septic patients. To date, a limited number of biomarkers that could predict cardiomyocyte apoptosis have been explored. In this study, we successfully established a cecal ligation and puncture (CLP)-induced septic model, and it was found that miR-501-5p expression was down-regulated in peripheral blood samples of septic patients with cardiac dysfunction, lipopolysaccharide (LPS)-induced cardiomyocytes, and the myocardium and peripheral blood in the septic model. Moreover, it was revealed that miR-501-5p overexpression could increase left ventricular diastolic pressure (LVDP), fractional shortening (FS), ejection fraction (EF), and maximum rate of the rise of left ventricular pressure (+dp/dt) in vivo, while it decreased the levels of myocardial injury-related indicators. In addition, LPS induction accelerated apoptosis and elevated the inflammation in HL-1 and HCM cells, which could be reversed by miR-501-5p overexpression. Mechanistically, we considered nuclear receptor subfamily 4 group A member 3 (NR4A3) as the target of miR-501-5p, and it was found that miR-501-5p prevented the binding between NR4A3 and Bcl-2. It was found that miR-501-5p exerted an inhibitory effect on cardiomyocyte apoptosis and inflammation in a NR4A3-dependent manner. Overall, our results may provide evidence for consideration of miR-501-5p in the therapy of sepsis.

Pterostilbene Interferes With Lipopolysaccharide-Induced Myocardial Injury Through Oxidative Stress and Inflammasome Pathways

Myocardial contractile dysfunction caused by sepsis is a serious threat to human health, and its pathogenesis is not completely clear. It is generally believed that excessive inflammation and oxidative stress are the main causes of myocardial damage caused by sepsis. Pterostilbene (PTS) has a variety of biological activities, including anti-oxidant, anti-inflammatory, and anti-aging. Whether PTS protect myocardial function in rats with sepsis through anti-inflammatory and anti-oxidant effects has not been reported. In this study, we investigated the role of PTS in septic mice induced by lipopolysaccharide (LPS). Mice were injected intraperitoneally with LPS (20 mg/kg) to simulate sepsis. Use Echocardiography, Masson, DHE, H&E, IHC, IF and other experimental methods to explore the effects of PTS on LPS. The results showed that PTS was indicated to significantly increase the cardiac function of mice with sepsis. PTS treatment also reduced the mRNA expression of IL-1α, IL-6, MCP-1, and IL-1β and the protein expression of NLRP3 in vivo and in vitro, and inhibited the migration of inflammatory cells. PTS treatment also reduced the mRNA expression of collagen I, collagen III and α-SMA, and inhibited fibrosis. PTS treatment reduced the mRNA expression of NOX1, NOX2, and NOX4 and inhibited DHE levels in vivo and in vitro. In summary, our data indicated that PTS played a crucial role in LPS-induced myocardial injured and might be a key target for the prevention and treatment of sepsis-induced myocardial dysfunction.

Mechanism of miR-126 in hypoxia-reoxygenation-induced cardiomyocyte pyroptosis by regulating HMGB1 and NLRP3 inflammasome

OBJECTIVE

Pyroptosis refers to the programmed cell death. This study evaluated the mechanism of miR-126 in hypoxia-reoxygenation (HR)-induced cardiomyocyte pyroptosis.

METHODS

The HR rat cardiomyocyte models were established. The cell viability, cytotoxicity, and levels of miR-126, pro-caspase-1 (p45), activated caspase-1 (p20/p10), caspase-11, gasdermin D (GSDMD), and GSDMD-N were detected. The cells were transfected with miR-126 mimics to verify the effect on rat cardiomyocyte pyroptosis, and added with HMGB1 inhibitor (Glycyrrhizin) or NLRP3 inhibitor (S3680) to explore the regulatory mechanisms on rat cardiomyocyte pyroptosis. The binding relationship of miR-126 and HMGB1 was explored. The regulatory effect of miR-126 and HMGB1 on HR-stimulated cardiomyocytes was verified through co-transfection with miR-126 mimics and pcDNA3.1-HMGB1.

RESULTS

HR treatment inhibited rat cardiomyocyte viability and increased cytotoxicity. After HR treatment, pro-caspase-1 (p45), activated caspase-1 (p20/p10), caspase-11, GSDMD, and GSDMD-N were elevated in rat cardiomyocytes, while miR-126 was evidently downregulated in rat cardiomyocytes. miR-126 overexpression, and inhibition of HMGB1 or NLRP3 partially reversed HR-induced rat cardiomyocyte cytotoxicity and pyroptosis. miR-126 targeted HMGB1 and HMGB1 overexpression partly reversed the inhibition of miR-126 overexpression on HR-induced cardiomyocyte pyroptosis.

CONCLUSION

miR-126 inhibits HMGB1/NLRP3 activity and the caspase-1/11 activation and reduces the GSDMD-N cleaved from GSDMD, ultimately inhibiting HR-induced cardiomyocyte pyroptosis.

Emodin Alleviates High-Glucose-Induced Pancreatic β-Cell Pyroptosis by Inhibiting NLRP3/GSDMD Signaling

Diabetes mellitus (DM) is a chronic noninfectious disease that is mainly featured by pancreatic β-cell (β-cell) dysfunction and impaired glucose homeostasis. Currently, the pathogenesis of dysfunction of the β-cells in DM remains unclear, and therapeutic approaches to it are limited. Emodin (EMD), a natural anthraquinone derivative, has been preliminarily proven to show antidiabetic effects. However, the underlying mechanism of EMD on β-cells still needs to be elucidated. In this study, we investigated the protective effects of EMD on the high glucose (50 mM)-induced INS-1 cell line and the underlying mechanism. INS-1 cells were treated with EMD (5, 10, and 20 μM) when exposed to high glucose. The effects of EMD were examined by using the inverted phase-contrast microscope, qRT-PCR, ELISA, and western blot. The results showed that EMD could alleviate cellular morphological changes, suppress IL-1β and LDH release, and promote insulin secretion in high-glucose-induced INS-1 cells. Furthermore, EMD inhibits NOD-like receptor protein 3 (NLRP3) activation and gasdermin D (GSDMD) cleavage to alleviate pyroptosis induced by high glucose. Overexpression of NLRP3 reversed the above changes caused by EMD. Collectively, our findings suggest that EMD attenuates high-glucose-induced β-cell pyroptosis by inhibiting NLRP3/GSDMD signaling.

Research Progress in Chinese Herbal Medicines for Treatment of Sepsis: Pharmacological Action, Phytochemistry, and Pharmacokinetics

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection; the pathophysiology of sepsis is complex. The incidence of sepsis is steadily increasing, with worldwide mortality ranging between 30% and 50%. Current treatment approaches mainly rely on the timely and appropriate administration of antimicrobials and supportive therapies, but the search for pharmacotherapies modulating the host response has been unsuccessful. Chinese herbal medicines, i.e., Chinese patent medicines, Chinese herbal prescriptions, and single Chinese herbs, play an important role in the treatment of sepsis through multicomponent, multipathway, and multitargeting abilities and have been officially recommended for the management of COVID-19. Chinese herbal medicines have therapeutic actions promising for the treatment of sepsis; basic scientific research on these medicines is increasing. However, the material bases of most Chinese herbal medicines and their underlying mechanisms of action have not yet been fully elucidated. This review summarizes the current studies of Chinese herbal medicines used for the treatment of sepsis in terms of clinical efficacy and safety, pharmacological activity, phytochemistry, bioactive constituents, mechanisms of action, and pharmacokinetics, to provide an important foundation for clarifying the pathogenesis of sepsis and developing novel antisepsis drugs based on Chinese herbal medicines.