Downregulation of macrophage migration inhibitory factor attenuates NLRP3 inflammasome mediated pyroptosis in sepsis-induced AKI

S-nitrosoglutathione inhibits pyroptosis of kidney tubular epithelial cells in sepsis via the SIRT3/SOD2/mtROS signaling pathway

OBJECTIVES

Pyroptosis is considered to play an important role in the occurrence, development and prognosis of septic acute kidney injury (SAKI). We aimed to explore the specific molecular mechanism of S-nitrosoglutathione (SNG) regulating pyroptosis of kidney tubular epithelial cells (KTECs).

METHODS

By constructing a mice model of sepsis, we pretreated them with SNG and used biochemical methods to detect the levels of serum inflammatory factors and mitochondrial reactive oxygen species (mtROS), assessed the severity of kidney injury and KTECs mitochondrial damage, and detected the expression of KTECs pyroptosis-related proteins and sirtuin 3 (SIRT3)/superoxide dismutase 2 (SOD2) pathway proteins.

RESULTS

The kidney injury caused by sepsis was significantly aggravated, and the levels of IL-1β, IL-6, IL-18, TNF-α, malondialdehyde (MDA) and mtROS were all increased, accompanied by the decrease of SIRT3 and SOD2 proteins, while NOD-like receptor with pyrin domain 3 (NLRP3), gasdermin D (GSDMD), Caspase-1 proteins expression and the number of KTECs apoptotic cells were all increased. However, after SNG pretreatment, the levels of IL-1β, IL-6, IL-18, TNF-α, MDA and mtROS were all significantly decreased, the expression of SIRT3 and SOD2 proteins were increased, NLRP3, GSDMD, Caspase-1 proteins expression and the number of KTECs apoptotic cells were decreased.

CONCLUSIONS

SNG protects SAKI by regulating the SIRT3/SOD2/mtROS signaling pathway to inhibit the pyroptosis of KTECs.

The Rough Morphotype of Mycobacterium abscessus Enhances Its Virulence Through ROS/p65/NLRP3/GSDMD-Mediated Macrophage Pyroptosis

The rough morphotype of Mycobacterium abscessus exhibits significantly higher virulence compared to the smooth morphotype, yet the underlying molecular mechanisms remain incompletely understood. Pyroptosis in macrophages plays a pivotal role in lung tissue damage; however, its specific involvement in Mycobacterium abscessus infection remains to be fully clarified. In this study, we identified that the rough morphotype of Mycobacterium abscessus upregulates the ROS/p65/NLRP3/GSDMD signalling pathway, thereby mediating pyroptosis in THP-1-derived macrophages. This heightened ability to induce macrophage pyroptosis is attributed to the bacterium's capacity to sustain intracellular viability and proliferation. These findings offer valuable insights into the virulence mechanisms of Mycobacterium abscessus and provide a foundation for future therapeutic interventions.

Targeting Stat3 with conditional knockout or PROTAC technology alleviates renal injury by Limiting pyroptosis

BACKGROUND

Acute kidney injury (AKI) is a critical clinical syndrome with high morbidity, mortality, and no effective treatment in clinical practice. The role of the Signal Transducer and Activator of Transcription 3 (Stat3) in AKI remains controversial, and its complex regulatory mechanisms must be further explored.

METHODS

We generated renal tubular epithelial cells Stat3 conditional knockout (cKO) mice and used them in cecal ligation and puncture (CLP) and ischaemia-reperfusion (I/R) induced AKI models. Additionally, proteolysis-targeting chimaera (PROTAC) compound E034 was designed and synthesised. We also utilised human kidney tissues, mouse renal tubular epithelial cells (mTECs) and HK-2 cells for further studies, including immunohistochemistry, Western blot analysis, Real-time PCR, chromatin immunoprecipitation (ChIP) and RNA sequencing, scanning electron microscopy (SEM) and Co-Immunoprecipitation (Co-IP) assay.

FINDINGS

An upregulation of total Stat3 protein was observed in AKI mouse models, which correlated with patient biopsy results. This increase may be attributed to histone H3K27 acetylation. Stat3 knockout in renal tubular epithelial cells significantly reduced AKI injury and inflammation in mice. Mechanistically, Stat3 induces the transcription of tripartite motif-containing protein 21 (Trim21), triggering a cascade that activates gasdermin D (Gsdmd), resulting in pyroptosis. Administration of E034, which selectively targets Stat3 for ubiquitination and degradation, significantly alleviated renal injury in a low-dose, single-dose regimen.

INTERPRETATION

In the context of renal injury, PROTAC emerges as a promising modality by explicitly targeting the Stat3/Trim21/Gsdmd axis, which our study has identified as a potential therapeutic target, potentially endowing clinically significant therapeutic strategies.

FUNDING

This work was supported by the National Key R&D Program (2022YFC2502503), the National Natural Science Foundation of China (No. 82270738), the National Natural Science Foundation of China (No. 82400806) and the Graduate Research and Practice Innovation Project of Anhui Medical University (YJS20230059).

Pyroptosis in sepsis-associated acute kidney injury: mechanisms and therapeutic perspectives

Sepsis-associated acute kidney injury (S-AKI) is a severe complication characterized by high morbidity and mortality, driven by multi-organ dysfunction. Recent evidence suggests that pyroptosis, a form of programmed cell death distinct from apoptosis and necrosis, plays a critical role in the pathophysiology of S-AKI. This review examines the mechanisms of pyroptosis, focusing on inflammasome activation (e.g., NLRP3), caspase-mediated processes, and the role of Gasdermin D in renal tubular damage. We also discuss the contributions of inflammatory mediators, oxidative stress, and potential therapeutic strategies targeting pyroptosis, including inflammasome inhibitors, caspase inhibitors, and anti-inflammatory therapies. Lastly, we highlight the clinical implications and challenges in translating these findings into effective treatments, underscoring the need for personalized medicine approaches in managing S-AKI.

Innate immune cells in acute and chronic kidney disease

Acute kidney injury (AKI) and chronic kidney disease (CKD) are inter-related clinical and pathophysiological disorders. Cells of the innate immune system, such as granulocytes and macrophages, can induce AKI through the secretion of pro-inflammatory mediators such as cytokines, chemokines and enzymes, and the release of extracellular traps. In addition, macrophages and dendritic cells can drive the progression of CKD through a wide range of pro-inflammatory and pro-fibrotic mechanisms, and by regulation of the adaptive immune response. However, innate immune cells can also promote kidney repair after acute injury. These actions highlight the multifaceted nature of the way by which innate immune cells respond to signals within the kidney microenvironment, including interaction with the complement and coagulation cascades, cells of the adaptive immune system, intrinsic renal cells and infiltrating mesenchymal cells. The factors and mechanisms that underpin the ability of innate immune cells to contribute to renal injury or repair and to drive the progression of CKD are of great interest for understanding disease processes and for developing new therapeutic approaches to limit AKI and the AKI-to-CKD transition.

Perillaldehyde ameliorates sepsis-associated acute kidney injury via inhibiting HSP90AA1-mediated ferroptosis and pyroptosis: Molecular structure and protein interaction of HSP90AA1

Heat shock protein 90α (HSP90AA1) is a molecular chaperone involved in a variety of cellular processes. Special attention is paid to how perillaldehyde ameliorates kidney injury by inhibiting HSP90AA1-mediated iron and pyrotoxicity, and in-depth analysis of the molecular structure and protein interactions of HSP90AA-1. The interaction between perillaldehyde and HSP90AA1 and the effect of perillaldehyde on the molecular structure of HSP90AA1 were analyzed by molecular docking and surface plasmon resonance technique. Western blot and immunohistochemical results showed that perillaldehyde could decrease the expression of HSP90AA1 and change its distribution in the kidney. Molecular docking and surface plasmonic resonance experiments revealed the high affinity binding between perillaldehyde and HSP90AA1, and further analysis showed that perillaldehyde could induce the conformational change of HSP90AA1, thereby inhibiting its function.

Elevated levels of IRF1 and CASP1 as pyroptosis-related biomarkers for intestinal epithelial cells in Crohn's disease

Introduction

Crohn's disease (CD) is a complex inflammatory condition with the potential for severe complications. Pyroptosis is an inflammatory form of programmed cell death, and the role of pyroptosis in intestinal epithelial cells of CD remains unclear.

Methods

In this study, pyroptosis-related hub genes were identified using datasets from the Gene Expression Omnibus database through differential expression analysis, machine learning algorithms, and single-cell sequencing analysis. Hub gene expression was validated using clinical samples and a trinitrobenzene sulfonic acid (TNBS)-induced colitis rat model.

Results

Six pyroptosis-related hub genes (CASP1, IRF1, ZBP1, MLKL, MMP1, HTRA1) were identified. IRF1 and CASP1 exhibited significant upregulation in CD, including both colonic and ileal subtypes, with good diagnostic value across different CD subtypes. Additionally, these two genes were not elevated in any other intestinal disorders, except for ulcerative colitis. Single-cell sequencing analysis revealed a significant interaction between intestinal epithelial cells (IECs) and monocytes. The clinical samples further confirmed that the mRNA levels of IRF1 and CASP1 were significantly higher in CD patients compared to healthy controls. Additionally, the colitis rat model validated the upregulation of Irf1 and Casp1 at both mRNA and protein levels.

Conclusion

Our findings identified IRF1 and CASP1 as critical pyroptosis-related biomarkers for IECs in CD, contributing to the understanding of pyroptosis in CD pathogenesis.

MIF/CD74 axis in hepatic stellate cells mediates HBV-related liver fibrosis

Chronic hepatitis B virus (HBV) infection is a major risk factor for liver fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Despite advances in understanding HBV-related liver diseases, effective therapeutic strategies remain limited. Macrophage migration inhibitory factor (MIF) has been implicated in various inflammatory and fibrotic conditions, but its role in HBV-induced liver fibrosis has not been fully explored. This study investigates the involvement of MIF in liver fibrosis and evaluates its potential as a therapeutic target. We found that MIF expression was significantly elevated in hepatic stellate cells (HSCs) following stimulation with HBVcc (HBV cell culture) or HBV surface antigen (HBsAg). Through its receptor CD74, MIF enhanced the TGF-β/SMAD signaling pathway, promoting HSC activation and liver fibrosis progression. Histological analysis revealed higher MIF and CD74 expression in HBsAg-positive individuals compared to HBsAg-negative controls. Moreover, MIF expression correlated with the activation of fibrosis markers, including α-SMA and TGF-β-related proteins. Inhibition of MIF with the specific inhibitor ISO-1 attenuated fibrosis progression, suggesting that targeting MIF could offer a promising approach for treating HBV-related liver fibrosis. Our findings underscore the critical role of the MIF/CD74 axis in liver fibrosis and provide a basis for future therapeutic strategies targeting MIF in chronic liver diseases.

Butyrate attenuates SA-AKI by inhibiting pyroptosis via the STING-GSDMD axis

Sepsis-associated acute kidney injury (SA-AKI) is a common and serious complication with high morbidity and mortality. The pathophysiology of SA-AKI is complex. The underlying mechanisms of SA-AKI remain unclear, and effective therapeutic strategies are limited. Butyrate is a type of short-chain fatty acid (SCFA) derived from the gut microbiota that plays a key role in kidney disease. However, the effect of butyrate on SA-AKI and its underlying mechanisms remain unclear. In this study, LPS was used to establish an SA-AKI model in C57BL/6 mice. Our results indicated that butyrate levels were substantially reduced in SA-AKI model mice. Notably, butyrate intervention attenuated kidney injury and inflammation in SA-AKI model mice. Moreover, the levels of NLRP3, STING, and GSDMD (a marker of pyroptosis) were significantly decreased by butyrate intervention. An in vitro model induced by LPS was established using HK-2 cells. Butyrate mitigated pyroptosis and reduced NLRP3, STING, and GSDMD protein expression. Furthermore, STING overexpression abrogated the downregulation of several proteins (NLRP3 and caspase 1) invovled in NLRP3 inflammsome-mediated pyroptosis and weakened the protective effect of butyrate. Hence, butyrate may attenuate SA-AKI by inhibiting pyroptosis via the STING-GSDMD axis, which provides a potential therapeutic strategy for preventing SA-AKI progression.

CIRCTMCO3 ALLEVIATES SEPSIS-INDUCED ACUTE KIDNEY INJURY VIA REGULATING MIR-218-5P/ZEB2 AXIS

ABSTRACT

Background: Growing evidence has found the critical role of circular RNAs (circRNAs) in sepsis-induced acute kidney injury (S-AKI). CircTMCO3 has been found to be involved in tumor microenvironment changes of ovarian cancer. This study aimed to explore whether circTMCO3 functions in S-AKI, and if so, to elucidate the molecular mechanism. Methods: CircTMCO3 expression was analyzed in lipopolysaccharide (LPS)-induced HK-2 cells and in the kidney tissues of mice treated with cecal ligation and puncture (CLP), respectively. Furthermore, the effects of circTMCO3 on S-AKI and the related mechanisms were evaluated in both models through gain- and/or loss-of-function strategies. Results: CircTMCO3 expression was suppressed in both S-AKI models. Upregulation of circTMCO3 mitigated LPS-induced apoptosis, oxidative stress, and inflammation in HK-2 cells. In contrast, circTMCO3 downregulation exacerbated LPS-induced injuries in HK-2 cells. Intravenous injection of circTMCO3 lentivirus to increase circTMCO3 expression improved renal function and attenuated kidney injury in S-AKI mice, as evidenced by the decrease in serum creatinine and blood urea nitrogen concentrations, amelioration of tubular pathological injury, reduction of renal cell apoptosis, and mitigation of oxidative stress and proinflammatory cytokines (TNF-α, IL-1β, and IL-6). Moreover, circTMCO3 directly targeted miR-218-5p, and the mimic of which abolished the protective effect of circTMCO3 in cell models. ZEB2 was identified to be a target of miR-218-5p; its downregulation not only reversed the impacts of miR-218-5p inhibitor on S-AKI, but also mitigated the effects mediated by circTMCO3 upregulation in vitro . Conclusions: CircTMCO3 protects against S-AKI by regulating miR-218-5p/ZEB2 axis, thereby mediating antiapoptotic, antioxidant, and anti-inflammatory activities. This indicates that increasing circTMCO3 expression might be a future therapeutic method for S-AKI.

Upregulation of Peripheral Blood NLRP3 and IL-18 in Patients With Acute Kidney Injury in Sepsis and Its Clinical Significance

BACKGROUND

Sepsis-associated acute kidney injury (SA-AKI) is a common complication that can lead to renal failure in patients, significantly affecting the prognosis and survival of patients.

OBJECTIVE

In this study, we aimed to evaluate the predictive value of NOD-like receptor protein 3 (NLRP3) and interleukin 18 (IL-18) in peripheral blood mononuclear cells (PBMCs) of SA patients for the occurrence of SA-AKI.

MATERIAL AND METHODS

We screened AKI-related data sets using the Gene Expression Omnibus (GEO) database and identified differentially expressed genes (DEGs) associated with AKI. KEGG and GO analysis were used to identify enriched molecular functions and pathways. The study included 62 SA patients admitted to the Department of Intensive Care Medicine of our hospital from February 2021 to June 2022, including 34 non-AKI cases and 28 AKI cases, and 25 healthy volunteers were used as the control group. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the levels of NLRP3 and IL-18 in PBMCs of the subjects.

RESULTS

Bioinformatics analysis and experimental validation showed that the expression levels of NLRP3 and IL-18 were significantly upregulated in SA-AKI patients. In addition, the expressions of NLRP3 and IL-18 were positively correlated with APACHE II scores. ROC curve analysis revealed that NLRP3 and IL-18 have the potential to diagnose SA-AKI.

CONCLUSION

This study provides preliminary evidence for NLRP3 and IL-18 as potential diagnostic biomarkers for SA-AKI.

MIF aggravates experimental autoimmune prostatitis through activation of the NLRP3 inflammasome via the PI3K/AKT pathway

In our investigation, we investigated the role of macrophage migration inhibitory factor (MIF), a key cytokine, in chronic nonbacterial prostatitis (CNP), an underexplored pathology. Elevated MIF expression was observed in the serum of individuals with chronic prostatitis-like symptoms (CP-LS) as well as in serum and tissue samples from experimental autoimmune prostatitis (EAP) mouse model. Treatment with ISO-1, a specific MIF antagonist, effectively mitigated prostatic inflammation and macrophage infiltration, thereby emphasizing the critical role of MIF in orchestrating immune responses within the prostate microenvironment. Further analyses revealed that MIF stimulates the PI3K/AKT and NLRP3 inflammasome pathways, which are integral to inflammation and cellular immunity. Pharmacological inhibition of the PI3K/AKT pathway by LY294002 substantially reduced prostatic inflammation and macrophage infiltration, potentially by inhibiting NLRP3 inflammasome activation. These findings collectively suggest that MIF is a potential diagnostic marker for CNP and suggest that targeting MIF or its downstream signalling pathways, PI3K/AKT and NLRP3, might represent a novel therapeutic strategy for this condition.

Apelinergic system in acute kidney injury: Mechanistic insights and therapeutic potential

Acute kidney injury (AKI) has emerged as a global health crisis, surpassing mortality rates associated with several cancers and heart failure. The lack of effective therapies, coupled with challenges in diagnosis and the high cost of kidney transplantation, underscores the urgent need to explore novel therapeutic targets and strategies for AKI. Understanding the intricate pathophysiology of AKI is paramount in this endeavor. The components of the apelinergic system-namely, apelin and elabela/toddler, along with their receptor-are prominently expressed in various kidney cells and have garnered significant attention in renal research. Recent studies have highlighted the renoprotective role of the apelinergic system in AKI. This system exerts its protective effects by modulating several pathophysiological processes, including reducing endoplasmic reticulum (ER) stress, improving mitochondrial dynamics, inhibiting inflammation and apoptosis, promoting diuresis through vasodilation of renal vasculature, and counteracting the effects of reactive oxygen species (ROS). Despite these advancements, the precise involvement of the apelinergic system in the progression of AKI remains unclear. Furthermore, the therapeutic potential of apelin-13 in AKI is not fully understood. This review aims to elucidate the role of the apelinergic system in AKI and its interactions with key pathomechanisms involved in the progression of AKI. Additionally, we discuss the current clinical status of exogenous apelin-13 therapy, providing insights that will guide future research on apelin against AKI.

The role of inflammatory response and metabolic reprogramming in sepsis-associated acute kidney injury: mechanistic insights and therapeutic potential

Sepsis represents a severe condition characterized by organ dysfunction resulting from a dysregulated host response to infection. Among the organs affected, the kidneys are particularly vulnerable, with significant functional impairment that markedly elevates mortality rates. Previous researches have highlighted that both inflammatory response dysregulation and metabolic reprogramming are crucial in the onset and progression of sepsis associated acute kidney injury (SA-AKI), making these processes potential targets for innovative therapies. This study aims to elucidate the pathophysiological mechanisms of renal injury in sepsis by perspective of inflammatory response dysregulation, with particular emphasis on pyroptosis, necroptosis, autophagy, and ferroptosis. Furthermore, it will incorporate insights into metabolic reprogramming to provide a detailed analysis of the mechanisms driving SA-AKI and explore potential targeted therapeutic strategies, providing solid theoretical framework for the development of targeted therapies for SA-AKI.

Therapy Targeted to the NLRP3 Inflammasome in Chronic Kidney Disease

Background

The NLRP3 inflammasome is a cytoplasmic polymeric protein complex composed of the cytoplasmic sensor NLRP3, the apoptosis-related spot-like protein ASC, and the inflammatory protease caspase-1. NLRP3 activates and releases IL-1β through classical pathways, and IL-18 mediates inflammation and activates gasdermin-D protein to induce cellular pyroptosis. Numerous studies have also emphasized the non-classical pathway activated by the NLRP3 inflammasome in chronic kidney disease (CKD) and the inflammasome-independent function of NLRP3.

Summary

The NLRP3-targeting inflammasome and its associated pathways have thus been widely studied in models of CKD treatment, but no drug that targets NLRP3 has thus far been approved for the treatment of CKD.

Key Messages

We herein reviewed the current interventional methods for targeting the NLRP3 inflammasome in various CKD models, analyzed their underlying mechanisms of action, classified and compared them, and discussed the advantages and follow-up directions of various interventional methods. This review therefore provides novel ideas and a reference for the development of targeted NLRP3-inflammasome therapy in CKD.

WIP1-mediated regulation of p38 MAPK signaling attenuates pyroptosis in sepsis-associated acute kidney injury

Wild-Type p53-Induced Phosphatase 1 (WIP1/PPM1D) is a serine/threonine phosphatase that plays a significant role in various physiological processes. However, the involvement of WIP1 in kidney remains unclear. Lipopolysaccharide (LPS) was administered to induce acute injury in mice and human kidney 2 (HK2) cells in the study. The WIP1 inhibitor, CCT007093, was administered both in vitro and in vivo to assess its effect on kidney. The single-cell sequencing (scRNA-seq) data revealed that Ppm1d mRNA reached peak on day 2 following unilateral ischemia-reperfusion injury (uni-IRI) in mice, especially in the proximal renal tubules during repair phase. Compared to the control group, WIP1 protein exhibited a significant increase in renal tubules of patients with acute tubular injury (ATI) and mice with LPS-induced acute kidney injury (AKI), as well as in LPS-injured HK2 cells. In vitro experiments showed that CCT007093 increased the protein levels of NLRP3, cleaved-Caspase1, GSDMD-N and IL-1β in HK2 cells and further reduced the viability of LPS-stimulated HK2 cells. In vivo experiments showed that inhibition of WIP1 activity with CCT007093 further increased cleaved-Caspase1, GSDMD-N protein levels in kidney tissue from mice with LPS-induced AKI. In addition, LPS induces phosphorylation of p38 MAPK, a key regulator of pyroptosis, which is further activated by CCT007093. In conclusion, inhibition of WIP1 activity acts as a positive regulator of renal tubular pyroptosis mainly through the mediation of phospho-p38 MAPK.

Extreme Heat Exposure Induced Acute Kidney Injury through NLRP3 Inflammasome Activation in Mice

Climate change has resulted in a marked increase in heat extremes that carry a severe risk for morbidity and mortality. Kidney is sensitive to heat stimulation, and acute kidney injury (AKI) is the early event. In this study, we investigated the adverse effects of heat extremes and their underlying mechanism. A total of 16 wild-type C57BL/6N mice were randomly divided into groups of control (exposed to 22 ± 0.5 °C) and heat (exposed to 39.5 ± 0.5 °C until the core body temperature reached the maximum). First, extreme heat exposure induced AKI evidenced by kidney dysfunction and morphological impairment. In addition, heat exposure suppressed expression of molecules for mitochondrial energetics and fatty acid beta-oxidation and disturbed the balance of oxidative stress in the kidney. Moreover, heat exposure enhanced the protein levels in the upstream signaling pathway for NLRP3 inflammasome formation, followed by NLRP3 inflammasome activation and inflammatory cytokine production. These findings demonstrated that acute extreme heat exposure may induce AKI through the NLRP3 inflammasome formation and activation.

B-lymphocyte-induced maturation protein-1 inhibits inflammation and pyroptosis to alleviate sepsis injury

Liver and lung tissue damage caused by sepsis is still one of the causes of death. B-lymphocyte-induced maturation protein-1 (Blimp-1) has a protective role in inflammation-related disease. However, whether Blimp-1 can regulate cell pyroptosis and affect disease progression in sepsis is still unclear. Animal and cell models were established by the cecal ligation and puncture method and lipopolysaccharides (LPS)-induced RAW 264.7 cells, respectively, and the role of Blimp-1 in regulation inflammatory response and pyroptosis was verified. The changes of inflammation and pyroptosis in liver and lung tissues of septic mice were determined by the addition of TAK-242 (TLR4 inhibitor). Cell pyroptosis and the level of inflammation was detected after Blimp-1 knockdown and TAK-242 treatment in the cell model. The expression of Blimp-1 was continuously increased in a septic mice model. After treatment with TAK-242, the expression of Blimp-1, pyroptosis and inflammatory levels were reduced in mice. In the LPS-induced cell model, cell injury by knockout Blimp-1 was increased, and cell activity was restored after TAK-242 intervention. Overexpression of Blimp-1 relieved LPS-induced cellular inflammatory damage and pyroptosis. Our study had shown that Blimp-1 could improve septic damage by regulating the level of cellular inflammation and pyroptosis in sepsis.

The role and mechanism of pyroptosis and potential therapeutic targets in non-alcoholic fatty liver disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) is a clinical pathological syndrome characterized by the excessive accumulation of fat within liver cells, which can progress to end-stage liver disease in severe cases, posing a threat to life. Pyroptosis is a distinct, pro-inflammatory form of cell death, differing from traditional apoptosis. In recent years, there has been growing research interest in the association between pyroptosis and NAFLD, encompassing the mechanisms and functions of pyroptosis in the progression of NAFLD, as well as potential therapeutic targets. Controlled pyroptosis can activate immune cells, eliciting host immune responses to shield the body from harm. However, undue activation of pyroptosis may worsen inflammatory responses, induce cellular or tissue damage, disrupt immune responses, and potentially impact liver function. This review elucidates the involvement of pyroptosis and key molecular players, including NOD-like receptor thermal protein domain associated protein 3(NLRP3) inflammasome, gasdermin D (GSDMD), and the caspase family, in the pathogenesis and progression of NAFLD. It emphasizes the promising prospects of targeting pyroptosis as a therapeutic approach for NAFLD and offers valuable insights into future directions in the field of NAFLD treatment.

Macrophage migration inhibitory factor (MIF) suppresses mitophagy through disturbing the protein interaction of PINK1-Parkin in sepsis-associated acute kidney injury

Damage to renal tubular epithelial cells (RTECs) signaled the onset and progression of sepsis-associated acute kidney injury (SA-AKI). Recent research on mitochondria has revealed that mitophagy plays a crucial physiological role in alleviating injury to RTECs and it is suppressed progressively by the inflammation response in SA-AKI. However, the mechanism by which inflammation influences mitophagy remains poorly understood. We examined how macrophage migration inhibitory factor (MIF), a pro-inflammatory protein, influences the PINK1-Parkin pathway of mitophagy by studying protein-protein interactions when MIF was inhibited or overexpressed. Surprisingly, elevated levels of MIF were found to directly bind to PINK1, disrupting its interaction with Parkin. This interference hindered the recruitment of Parkin to mitochondria and impeded the initiation of mitophagy. Furthermore, this outcome led to significant apoptosis of RTECs, which could, however, be reversed by an MIF inhibitor ISO-1 and/or a new mitophagy activator T0467. These findings highlight the detrimental impact of MIF on renal damage through its disruption of the interaction between PINK1 and Parkin, and the therapeutic potential of ISO-1 and T0467 in mitigating SA-AKI. This study offers a fresh perspective on treating SA-AKI by targeting MIF and mitophagy.

Zn2+ improves sepsis-induced acute kidney injury by upregulating SIRT7-mediated Parkin acetylation

Zn2+ levels are reported to be correlated with kidney function. We explored the significance of Zn2+ in sepsis-induced acute kidney injury (SI-AKI) through the regulation of sirtuin 7 (SIRT7) activity. The sepsis rat model was established by cecal ligation and perforation (CLP) and intraperitoneally injected with ZnSO4 or SIRT7 inhibitor 97491 (SIRT7i), with renal tubular injury assessed by hematoxylin and eosin staining. In vitro, human renal tubular epithelial cells (HK-2) were induced with lipopolysaccharide to obtain a renal injury cell model, followed by ZnSO4 or SIRT7i and autophagy inhibitor (3-methyladenine) treatment. Interleukin (IL)-1β, IL-18, reactive oxygen species (ROS), Parkin acetylation level, kidney injury molecule-1 (KIM-1), and neutrophil gelatinase-associated lipocalin (NGAL) expression levels were determined. The renal tubule injury, inflammation condition, and pyroptosis-related and autophagy-related protein levels were assessed. The pyroptosis in kidney tissues and autophagosome formation were observed by transmission electron microscopy. Zn2+ alleviated renal injury in CLP rats and inhibited pyroptosis and its related protein levels by inhibiting SIRT7 activity in septic rat renal tissues. In vitro, Zn2+ increased HK-2 cell viability and reduced KIM-1, NGAL, IL-1β, IL-18, NLRP3 inflammasome, cleaved caspase-1, gasdermin D-N levels, and pyroptotic cell number. Zn2+ increased autophagosome number and LC3BII/LC3BI ratio and decreased TOM20, TIM23, P62, and mitochondrial ROS levels. Zn2+ increased Parkin acetylation by repressing SIRT7 activity. Inhibiting mitophagy partially averted Zn2+-inhibited NLRP3 inflammasome activation and apoptosis in HK-2 cells. Zn2+ upregulated Parkin acetylation by repressing SIRT7 activity to promote mitophagy and inhibit NLRP3 inflammasome activation and pyroptosis, thus improving SI-AKI.NEW & NOTEWORTHY Zn2+ upregulated Parkin acetylation by repressing sirtuin 7 activity to promote mitophagy and inhibit NLRP3 inflammasome activation and pyroptosis, thus improving sepsis-induced acute kidney injury.

Bibliometric and visual analysis of immunisation associated with acute kidney injury from 2003 to 2023

Objective

This study aims to conduct a detailed bibliometric and visual analysis of acute kidney injury (AKI) and immune-related research conducted over the past two decades, focusing on identifying emerging trends and key areas of interest.

Methods

The Web of Science Core Collection (WoSCC) was utilised for the meticulous examination of various parameters including publication volume, authorship, geographic distribution, institutional contributions, journal sources, prevalent keywords and citation frequencies. Data were intricately visualised and interpreted using VOSviewer, CiteSpace and Excel 365 software.

Results

Analysis of the WoSCC database revealed 3,537 articles on AKI and immunisation, originating from 94 countries and regions, involving 3,552 institutions and authored by 18,243 individuals. Notably, the top five countries contributing to this field were the United States, China, Germany, Italy and the United Kingdom, with the United States leading with 35.76% of total publications. Among the 3,552 contributing institutions, those in the United States were predominant, with Harvard University leading with 134 papers and 3,906 citations. Key journals driving productivity included Frontiers in Immunology, Kidney International, Journal of the American Society of Nephrology and International Journal of Molecular Sciences, with Kidney International being the most cited, followed by Journal of the American Society of Nephrology and New England Journal of Medicine. Prominent authors in the field included Ronco Claudio, Okusa Mark D and Anders, Hans-Joachim. Co-citation clustering and timeline analysis highlighted recent research foci such as COVID-19, immune checkpoint inhibitors, regulated necrosis, cirrhosis and AKI. Keyword analysis identified "inflammation," "ischaemia-reperfusion injury," "sepsis," "covid-19," and "oxidative stress" as prevalent terms.

Conclusion

This study provides the first bibliometric analysis of AKI and immune research, offering a comprehensive overview of research hotspots and evolving trends within the field.

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.

Pellino1 orchestrates gut-kidney axis to perpetuate septic acute kidney injury through activation of STING pathway and NLRP3 inflammasome

AIMS

Intestinal barrier dysfunction is the initial and propagable factor of sepsis in which acute kidney injury (AKI) has been considered as a common life-threatening complication. Our recent study identifies the regulatory role of Pellino1 in tubular death under inflammatory conditions in vitro. The objective of our current study is to explore the impact of Pellino1 on gut-kidney axis during septic AKI and uncover the molecular mechanism (s) underlying this process.

MATERIALS AND METHODS

Immunohistochemistry (IHC) was conducted to evaluate Pellino1 and NOD-like receptor thermal protein domain associated protein 3 (NLRP3) levels in renal biopsies from critically ill patients with a clinical diagnosis of sepsis. Functional and mechanistic studies were characterized in septic models of the Peli-knockout (Peli1-/-) mice by histopathological staining, enzyme-linked immunosorbent assay (ELISA), flow cytometry, immunofluorescence, biochemical detection, CRISPR/Cas9-mediated gene editing and intestinal organoid.

KEY FINDINGS

Pellino1, together with NLRP3, are highly expressed in renal biopsies from critically ill patients diagnosed with sepsis and kidney tissues of septic mice. The Peli1-/- mice with sepsis become less prone to develop AKI and have markedly compromised NLRP3 activation in kidney. Loss of Peli1 endows septic mice refractory to intestinal inflammation, barrier permeability and enterocyte apoptosis that requires stimulator of interferons genes (STING) pathway. Administration of STING agonist DMXAA deteriorates AKI and mortality of septic Peli1-/- mice in the presence of kidney-specific NLRP3 reconstitution.

SIGNIFICANCE

Our studies suggest that Pellino1 has a principal role in orchestrating gut homeostasis towards renal pathophysiology, thus providing a potential therapeutic target for septic AKI.

Japanese encephalitis virus NS1 and NS1' protein disrupts the blood-brain barrier through macrophage migration inhibitory factor-mediated autophagy

Flaviviruses in the Japanese encephalitis virus (JEV) serogroup, such as JEV, West Nile virus, and St. Louis encephalitis virus, can cause severe neurological diseases. The nonstructural protein 1 (NS1) is a multifunctional protein of flavivirus that can be secreted by infected cells and circulate in the host bloodstream. NS1' is an additional form of NS1 protein with 52 amino acids extension at its carboxy-terminal and is produced exclusively by flaviviruses in the JEV serogroup. In this study, we demonstrated that the secreted form of both NS1 and NS1' can disrupt the blood-brain barrier (BBB) of mice, with NS1' exhibiting a stronger effect. Using the in vitro BBB model, we found that treatment of soluble recombinant JEV NS1 or NS1' protein increases the permeability of human brain microvascular endothelial cells (hBMECs) and leads to the degradation of tight junction proteins through the autophagy-lysosomal pathway. Consistently, NS1' protein exhibited a more pronounced effect compared to NS1 in these cellular processes. Further research revealed that the increased expression of macrophage migration inhibitory factor (MIF) is responsible for triggering autophagy after NS1 or NS1' treatment in hBMECs. In addition, TLR4 and NF-κB signaling was found to be involved in the activation of MIF transcription. Moreover, administering the MIF inhibitor has been shown to decrease viral loads and mitigate inflammation in the brains of mice infected with JEV. This research offers a novel perspective on the pathogenesis of JEV. In addition, the stronger effect of NS1' on disrupting the BBB compared to NS1 enhances our understanding of the mechanism by which flaviviruses in the JEV serogroup exhibit neurotropism.IMPORTANCEJapanese encephalitis (JE) is a significant viral encephalitis worldwide, caused by the JE virus (JEV). In some patients, the virus cannot be cleared in time, leading to the breach of the blood-brain barrier (BBB) and invasion of the central nervous system. This invasion may result in cognitive impairment, behavioral disturbances, and even death in both humans and animals. However, the mechanism by which JEV crosses the BBB remains unclear. Previous studies have shown that the flavivirus NS1 protein plays an important role in causing endothelial dysfunction. The NS1' protein is an elongated form of NS1 protein that is particularly produced by flaviviruses in the JEV serogroup. This study revealed that both the secreted NS1 and NS1' of JEV can disrupt the BBB by breaking down tight junction proteins through the autophagy-lysosomal pathway, and NS1' is found to have a stronger effect compared to NS1 in this process. In addition, JEV NS1 and NS1' can stimulate the expression of MIF, which triggers autophagy via the ERK signaling pathway, leading to damage to BBB. Our findings reveal a new function of JEV NS1 and NS1' in the disruption of BBB, thereby providing the potential therapeutic target for JE.

Cytosolic mtDNA-cGAS-STING axis contributes to sepsis-induced acute kidney injury via activating the NLRP3 inflammasome

BACKGROUND

NLRP3 inflammasome activation is significantly associated with sepsis-induced acute kidney injury (S-AKI). Cytosolic DNA derived from damaged mitochondria has been reported to activate NLRP3 inflammasome via upregulating the cyclic GMP-AMP synthase (cGAS)-the stimulator of interferon genes (STING) axis in nucleus pulposus cell and cardiomyocytes. However, the regulatory effect of mitochondria DNA (mtDNA)-cGAS-STING axis on the NLRP3 inflammasome in S-AKI remains unclear.

METHODS

In the current study, we established an in vivo model of S-AKI by intraperitoneally injecting male C57BL/6 J mice with lipopolysaccharide (LPS). Next, selective cGAS inhibitor RU.521, and STING agonist DMXAA were intraperitoneally injected in the mice; then, blood urea nitrogen (BUN), serum creatinine (CRE), urinary kidney injury molecular-1 (KIM-1), pathological changes, and infiltrated neutrophils were detected to assess kidney injury. We also performed western blot and immunofluorescence assays to evaluate STING, cGAS, TBK-1, p-TBK-1, IRF3, p-IRF3, NF-kB, p-NF-kB, NLRP3, cleaved caspase-1, caspase-1, GSDMD-N, and GSDMD expression levels in kidney tissues. IL-18 and IL-1β in renal tissue were identified by ELISA. In vitro, we treated HK-2 cells with LPS to establish a cell model of S-AKI. Furthermore, ethidium bromide (EtBr) was administered to deplete mitochondria DNA (mtDNA). LPS-induced cytotoxicity was evaluated by LDH release assay. Protein expression of cGAS, STING, and NLRP3 in was quantified by western blot. Cytosolic mtDNA was detected by immunofluorescence and q-PCR. Released IL-1β and IL-18 in HK-2 supernatants were detected by ELISA.

RESULTS

LPS injection induced S-AKI in mice, as evidenced by neutrophil infiltration, tubular vacuolation, and increased levels of serum creatinine (CRE), blood urea nitrogen (BUN), and urinary KIM-1. In addition, LPS activated the cGAS-STING axis and NLRP3 inflammasome in vivo, illustrated by increased phosphorylation levels of TBK-1, IRF3, and NF-kB protein, increased ratio of cleaved caspase-1 to caspase-1 and GSDMD-N to GSDMD, and increased IL-1β and IL-18 levels. Moreover, the cGAS inhibitor RU.521 effectively attenuated NLRP3 inflammasome and S-AKI; however, these effects were abolished by treatment with the STING agonist DMXAA. Furthermore, cytosolic release of mtDNA and activation of the cGAS-STING-NLRP3 axis were observed in LPS-treated HK-2 cells. Inhibiting mtDNA replication by Ethidium Bromide (EtBr) treatment reduced cytosolic mtDNA accumulation and downregulated the cGAS-STING-NLRP3 axis, ameliorating the cytotoxicity induced by LPS.

CONCLUSION

This study demonstrated that the cGAS-STING axis was triggered by cytosolic mtDNA and participated in the development of S-AKI by activating NLRP3 inflammasome. Reducing cytosolic mtDNA accumulation or inhibiting the cGAS-STING axis may be potential therapeutic targets for S-AKI.

The possible cardioprotective effect of ghrelin during experimental endotoxemia in mice

This study aimed to evaluate the cardioprotective effects of ghrelin in septic mice, focusing on its anti-inflammatory and antioxidant properties. Thirty-five male Swiss mice (8-12 weeks old, 23-33g) were randomly assigned to five groups (n = 7 each): (1) Normal, fed usual diets, (2) Sham, subjected to anesthesia and laparotomy, (3) Sepsis, subjected to cecal ligation and puncture, (4) Vehicle, given an equivalent volume of intraperitoneal saline injections immediately after cecal ligation and puncture, and (5) Ghrelin-treated, administered 80 µg/kg ghrelin intraperitoneal injections immediately following cecal ligation and puncture. Serum levels of tumor necrosis factor-alpha (TNF-α), macrophage migration inhibitory factor (MIF), toll-like receptor 4 (TLR4), and 8-epi-prostaglandin F2 alpha (8-epi-PGF2α) were measured. The extent of cardiac damage was also evaluated histologically. The mean serum levels of TNF-α, MIF, TLR4, and 8-epi-PGF2α levels were significantly higher in the sepsis and vehicle groups than in the normal and sham groups. The levels were significantly lower in the ghrelin-treated group than in the vehicle and sepsis groups. Histological analysis revealed normal myocardial architecture in the normal and sham groups, whereas the sepsis and vehicle groups had severe myocardial injury. The ghrelin-treated group displayed histological features similar to the sham group, indicating reduced myocardial damage. Ghrelin ameliorated sepsis-induced cardiotoxicity in mice by exhibiting strong anti-inflammatory and antioxidant effects. These findings suggest that ghrelin may be a promising therapeutic candidate for the prevention of sepsis-induced cardiotoxicity.

KNOCKDOWN OF CIRC_0114428 ALLEVIATES LPS-INDUCED HK2 CELL APOPTOSIS AND INFLAMMATION INJURY VIA TARGETING MIR-215-5P/TRAF6/NF-ΚB AXIS IN SEPTIC ACUTE KIDNEY INJURY

ABSTRACT

Background: Sepsis is a systemic inflammatory disease that can cause multiple organ damage. Circular RNAs (circRNAs) have been reported to play a regulatory role in sepsis-induced acute kidney injury (AKI); however, the role of circ_0114428 has not been studied. Methods: In this study, HK2 cells were treated with different concentrations of LPS to induce cell damage, and then the expressions of circ_0114428, microRNA-215-5p (miR-215-5p), and tumor necrosis factor receptor-associated factor 6 (TRAF6) were detected by quantitative real-time polymerase chain reaction (qRT-PCR), and Western blot examined the Bax and cleaved-Caspase-3 proteins. Cell proliferation was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and thymidine analog 5-ethynyl-2'-deoxyuridine (EdU) assay. In addition, cell apoptosis was detected by flow cytometry, and the levels of inflammatory factors were detected by enzyme-linked immunosorbent assay. Results: After LPS treatment with different concentrations, we found that LPS at 10 μg/mL had the best effect on HK2 cells. Circ_0114428 was highly expressed in sepsis-AKI patients and LPS-treated HK2 cells. Knockdown of circ_0114428 restored the effects of LPS treatment on proliferation, apoptosis, and inflammatory response of HK2 cells. MiR-215-5p was a target of circ_0114428, and TRAF6 was a downstream target of miR-215-5p. Circ_0114428 regulated TRAF6 expression by sponging miR-215-5p in LPS-treated HK2 cells. Circ_0114428 regulated LPS-induced NF-κB signaling in HK2 cells by targeting miR-215-5p/TRAF6 axis. Conclusion: Circ_0114428 knockdown abolished the cell proliferation, apoptosis, and inflammatory damage in LPS-induced HK2 cells by targeting miR-215-5p/TRAF6/NF-κB.

Pyroptosis: The Determinator of Cell Death and Fate in Acute Kidney Injury

Background

Acute kidney injury (AKI) is kidney damage that leads to a rapid decline in function. AKI primarily occurs when the tubular epithelium is damaged, causing swelling, loss of brush margin, and eventual apoptosis. Research has shown that tubular epithelial cell damage in AKI is linked to cell cycle arrest, autophagy, and regulation of cell death.

Summary

Pyroptosis, a type of programmed cell death triggered by inflammation, is believed to play a role in the pathophysiology of AKI. Cumulative evidence has shown that pyroptosis is the main cause of tubular cell death in AKI. Thus, targeted intervention of pyroptosis may be a promising therapeutic approach for AKI. This review delves deep into the cutting-edge research surrounding pyroptosis in the context of AKI, shedding light on its intricate mechanisms and potential implications for clinical practice. Additionally, we explore the exciting realm of potential preclinical treatment options for AKI, aiming to pave the way for future therapeutic advancements.

Key Messages

Pyroptosis, a highly regulated form of cell death, plays a crucial role in determining the fate of cells during the development of AKI. This intricate process involves the activation of inflammasomes, which are multi-protein complexes that initiate pyroptotic cell death. By understanding the mechanisms underlying pyroptosis, researchers aim to gain insights into the pathogenesis of AKI and potentially identify new therapeutic targets for this condition.

CHOP-mediated Gasdermin E expression promotes pyroptosis, inflammation, and mitochondrial damage in renal ischemia-reperfusion injury

In clinical practice, renal ischemia-reperfusion injury (IRI) is a common cause of acute kidney injury (AKI), often leading to acute renal failure or end-stage renal disease (ESRD). The current understanding of renal IRI mechanisms remains unclear, and effective therapeutic strategies and clear targets are lacking. Therefore, the need to find explicit and effective ways to reduce renal IRI remains a scientific challenge. The current study explored pyroptosis, a type of inflammation-regulated programmed cell death, and the role of Gasdermins E (GSDME)-mediated pyroptosis, mitochondrial damage, and inflammation in renal IRI. The analysis of human samples showed that the expression levels of GSDME in normal human renal tissues were higher than those of GSDMD. Moreover, our study demonstrated that GSDME played an important role in mediating pyroptosis, inflammation, and mitochondrial damage in renal IRI. Subsequently, GSDME-N accumulated in the mitochondrial membrane, leading to mitochondrial damage and activation of caspase3, which generated a feed-forward loop of self-amplification injury. However, GSDME knockout resulted in the amelioration of renal IRI. Moreover, the current study found that the transcription factor CHOP was activated much earlier in renal IRI. Inhibition of BCL-2 by CHOP leaded to casapse3 activation, resulting in mitochondrial damage and apoptosis; not only that, but CHOP positively regulated GSDME thereby causing pyroptosis. Therefore, this study explored the transcriptional mechanisms of GSDME during IRI development and the important role of CHOP/Caspase3/GSDME mechanistic axis in regulating pyroptosis in renal IRI. This axis might serve as a potential therapeutic target.

Polygonum cuspidatum Sieb. et Zucc. Extracts improve sepsis-associated acute kidney injury by inhibiting NF-κB-mediated inflammation and pyroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Polygonum cuspidatum Sieb. et Zucc. (Polygonum cuspidatum) is a herbaceous perennial plant in the Polygonaceae family that produces biofunctional stilbenes and quinones. The dried rhizome and root of P. cuspidatum in traditional oriental medicine have been used for ameliorating inflammatory illnesses, diabetes, gout, cancer, and other ailments.

AIM OF THE STUDY

This work aimed to investigate the protective effects of P. cuspidatum extracts (PCE) on sepsis-associated acute kidney injury (SA-AKI) and its underlying mechanism.

MATERIALS AND METHODS

The potential mechanisms by which PCE improved SA-AKI were preliminarily predicted by network pharmacology. The dry powders of PCE were obtained using the freeze-drying method. A mouse model of SA-AKI was established by intraperitoneal injection of lipopolysaccharide (LPS). The protective effects of PCE on SA-AKI in vivo were studied using pathological and biochemical methods. LPS-stimulated HK-2 cells were prepared for in vitro evaluation. The qPCR and immunoblotting assays were performed to confirm the mechanism involved.

RESULTS

The network pharmacology results indicate that emodin (Emo) and polydatin (PD) are potential active components of P. cuspidatum ameliorating SA-AKI. The experimental results showed that PCE improved renal function indices (creatinine, urea nitrogen, and urinary protein) in SA-AKI mice. Mechanistically, PCE mitigated oxidative stress, regulated the expression levels of pyroptosis-related proteins, and repressed the production of inflammatory cytokines by inactivating nuclear factor-kappa B (NF-κB) signaling in vivo. Similar results were observed in LPS-stimulated HK-2 cells in the presence of Emo or PD.

CONCLUSIONS

Our results demonstrated that PCE and active ingredients (Emo and PD) in PCE ameliorated SA-AKI by suppressing oxidative stress, inflammation, and pyroptosis.

Macrophage-derived exosomal miRNA-141 triggers endothelial cell pyroptosis by targeting NLRP3 to accelerate sepsis progression

Sepsis, critical condition marked by severe organ dysfunction from uncontrolled infection, involves the endothelium significantly. Macrophages, through paracrine actions, play a vital role in sepsis, but their mechanisms in sepsis pathogenesis remain elusive. Objective: We aimed to explore how macrophage-derived exosomes with low miR-141 expression promote pyroptosis in endothelial cells (ECs). Exosomes from THP-1 cell supernatant were isolated and characterized. The effects of miR-141 mimic/inhibitor on apoptosis, proliferation, and invasion of Human Umbilical Vein Endothelial Cells (HUVECs) were assessed using flow cytometry, CCK-8, and transwell assays. Key pyroptosis-related proteins, including caspase-1, IL-18, IL-1β, NLR Family Pyrin Domain Containing 3 (NLRP3), ASC, and cleaved-GSDMD, were analyzed via Western blot. The interaction between miR-141 and NLRP3 was studied using RNAhybrid v2.2 and dual-Luciferase reporter assays. The mRNA and protein level of NLRP3 after exosomal miR-141 inhibitor treatment was detected by qPCR and Western blot, respectively. Exosomes were successfully isolated. miR-141 mimic reduced cell death and pyroptosis-related protein expression in HUVECs, while the inhibitor had opposite effects, increasing cell death, and enhancing pyroptosis protein expression. Additionally, macrophage-derived exosomal miR-141 inhibitor increased cell death and pyroptosis-related proteins in HUVECs. miR-141 inhibits NLRP3 transcription. Macrophages facilitate sepsis progression by secreting miR-141 decreased exosomes to activate NLRP3-mediated pyroptosis in ECs, which could be a potentially valuable target of sepsis therapy.

LincRNA-EPS inhibits caspase-11 and NLRP3 inflammasomes in gingival fibroblasts to alleviate periodontal inflammation

To investigate the effects of long intergenic noncoding RNA-erythroid prosurvival (lincRNA-EPS) on periodontal inflammation mediated by inflammasomes and to explore its mechanism. Experimental periodontitis was induced in KO (lincRNA-EPS-/- ) and WT (lincRNA-EPS+/+ ) mice to compare the periodontal bone loss and inflammation by using micro-computed tomography, immunofluorescence staining and haematoxylin and eosin staining. The expression and activation of cysteinyl aspartate-specific proteinase-11 (caspase-11) and NOD-like receptor protein 3 (NLRP3) inflammasomes, as well as nuclear factor-kappa B (NF-κB) activation in mouse gingival fibroblasts (MGFs), were measured by real-time quantitative polymerase chain reaction, Western blotting, enzyme-linked immunosorbent and lactate dehydrogenase assays. MGFs were transfected with overexpression plasmids to assess the biological functions of lincRNA-EPS. RNA pull-down and immunoprecipitation experiments were performed to identify the interacting protein of lincRNA-EPS. LincRNA-EPS-expressing lentivirus was locally administered to inflamed periodontal tissues to evaluate its salvage function in periodontitis. The absence of lincRNA-EPS increased bone loss and expression of myeloperoxidase, interleukin-1α (IL-1α) and IL-1β in the inflammatory periodontium. LincRNA-EPS KO MGFs exhibited increased expression and activation of caspase-11/NLRP3 inflammasome components than WT MGFs under lipopolysaccharide (LPS) stimulation. The expression and activation of these molecules were inhibited in lincRNA-EPS overexpressed MGFs. Mechanistically, lincRNA-EPS directly bound to transactive response DNA-binding protein 43 (TDP43) in the nucleus of MGFs, and TDP43 knockdown exerted a similar inhibitory effect on NF-κB activation and the inflammasomes as lincRNA-EPS overexpression. Locally injecting lincRNA-EPS-expressing lentivirus weakened the periodontal damage. LincRNA-EPS inhibits the LPS-induced production and activation of caspase-11 and NLRP3 inflammasomes by suppressing the activation of the NF-κB signalling pathway via interacting with TDP43, thereby alleviating periodontitis.

The Role of Pyroptosis in the Pathogenesis of Kidney Diseases

BACKGROUND

Recently, in addition to apoptosis and necrosis, several other forms of cell death have been discovered, such as necroptosis, autophagy, pyroptosis, and ferroptosis. These cell death modalities play diverse roles in kidney diseases. Pyroptosis is a newly described type of proinflammatory programmed necrosis. Further exploring pyroptosis is helpful to slow the progression of kidney diseases and reduce their complications.

SUMMARY

Pyroptosis is mainly mediated by the cleavage of gasdermin D (GSDMD) along with downstream inflammasome activation. Activated caspase-1 induces the release of cytokines by cleaving GSDMD. Inflammation is a major pathogenic mechanism for kidney diseases. Increasing evidence corroborated that pyroptosis was closely related to the progression of renal diseases, including acute kidney injury, renal fibrosis, diabetic nephropathy, and kidney cancer. In this paper, we reviewed the role and the therapeutic treatment of pyroptosis in renal diseases.

KEY MESSAGES

The better understanding of the progress and new intervention approaches of pyroptosis in kidney diseases may pave the way for new therapeutic opportunities in clinical practice.

Exploring the anti-inflammatory activity of sulforaphane

Dysregulation of innate immune responses can result in chronic inflammatory conditions. Glucocorticoids, the current frontline therapy, are effective immunosuppressive drugs but come with a trade-off of cumulative and serious side effects. Therefore, alternative drug options with improved safety profiles are urgently needed. Sulforaphane, a phytochemical derived from plants of the brassica family, is a potent inducer of phase II detoxification enzymes via nuclear factor-erythroid factor 2-related factor 2 (NRF2) signaling. Moreover, a growing body of evidence suggests additional diverse anti-inflammatory properties of sulforaphane through interactions with mediators of key signaling pathways and inflammatory cytokines. Multiple studies support a role for sulforaphane as a negative regulator of nuclear factor kappa-light chain enhancer of activated B cells (NF-κB) activation and subsequent cytokine release, inflammasome activation and direct regulation of the activity of macrophage migration inhibitory factor. Significantly, studies have also highlighted potential steroid-sparing activity for sulforaphane, suggesting that it may have potential as an adjunctive therapy for some inflammatory conditions. This review discusses published research on sulforaphane, including proposed mechanisms of action, and poses questions for future studies that might help progress our understanding of the potential clinical applications of this intriguing molecule.

Theaflavin mitigates acute gouty peritonitis and septic organ injury in mice by suppressing NLRP3 inflammasome assembly

Activation of NLR family pyrin domain-containing 3 (NLRP3) inflammasome plays important role in defending against infections, but its aberrant activation is causally linked to many inflammatory diseases, thus being a therapeutic target for these diseases. Theaflavin, one major ingredient of black tea, exhibits potent anti-inflammatory and anti-oxidative activities. In this study, we investigated the therapeutic effects of theaflavin against NLRP3 inflammasome activation in macrophages in vitro and in animal models of related diseases. We showed that theaflavin (50, 100, 200 μM) dose-dependently inhibited NLRP3 inflammasome activation in LPS-primed macrophages stimulated with ATP, nigericin or monosodium urate crystals (MSU), evidenced by reduced release of caspase-1p10 and mature interleukin-1β (IL-1β). Theaflavin treatment also inhibited pyroptosis as shown by decreased generation of N-terminal fragment of gasdermin D (GSDMD-NT) and propidium iodide incorporation. Consistent with these, theaflavin treatment suppressed ASC speck formation and oligomerization in macrophages stimulated with ATP or nigericin, suggesting reduced inflammasome assembly. We revealed that theaflavin-induced inhibition on NLRP3 inflammasome assembly and pyroptosis resulted from ameliorated mitochondrial dysfunction and reduced mitochondrial ROS production, thereby suppressing interaction between NLRP3 and NEK7 downstream of ROS. Moreover, we showed that oral administration of theaflavin significantly attenuated MSU-induced mouse peritonitis and improved the survival of mice with bacterial sepsis. Consistently, theaflavin administration significantly reduced serum levels of inflammatory cytokines including IL-1β and attenuated liver inflammation and renal injury of mice with sepsis, concomitant with reduced generation of caspase-1p10 and GSDMD-NT in the liver and kidney. Together, we demonstrate that theaflavin suppresses NLRP3 inflammasome activation and pyroptosis by protecting mitochondrial function, thus mitigating acute gouty peritonitis and bacterial sepsis in mice, highlighting a potential application in treating NLRP3 inflammasome-related diseases.

Knockdown of PHLDA1 alleviates sepsis-induced acute lung injury by downregulating NLRP3 inflammasome activation

OBJECTIVE

To investigate the regulatory mechanism of pleckstrin homology-like domain, family A, member 1 (PHLDA1) in sepsis-induced acute lung injury (ALI).

METHOD

Mice model of sepsis were established by cecal ligation and puncture (CLP). The expression of PHLDA1 was reduced by injecting short hairpin RNA (shRNA)-PHLDA1 into the tail vein. The levels of PHLDA1, pro-inflammatory cytokines, such as interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), IL-1β, IL-18, super-oxide dismutase (SOD), malondialdehyde (MDA), and glutathione (GSH), molecular mechanism related to pyroptosis, such as caspase 1, adaptor apoptosis-associated speck-like protein containing a CARD (ASC), and gasdermin D (GSDMD)-N, and nucleotide oligomerization domain (NOD)-like receptor family pyrin domain-containing 3 (NLRP3) were tested by Western blot analysis, quantitative real-time polymerase chain reaction, and enzyme-linked-immunosorbent serologic assay. Pathological changes in lung tissues were examined by hematoxylin and eosin staining. Wet-dry weight ratio of lung tissues was observed.

RESULTS

The expression of PHLDA1 was up-regulated in lung tissues from CLP-induced septic mice. Knockdown of PHLDA1 could reduce lung injury and wet-dry weight ratio in mice with sepsis-induced ALI. Moreover, silencing of PHLDA1 decreased the expressions of IL-1β, TNF-α, IL-18, IL-6, and MDA but increased SOD and GSH expressions in CLP-induced septic mice. The expressions of NLRP3, GSDMD-N, ASC, and caspase 1 were decreased by PHLDA1 silencing.

CONCLUSION

Knockdown of PHLDA1 inhibited lung inflammation and pyroptosis in mice with sepsis-induced ALI by down-regulating NLRP3.

Nlrp3 Deficiency Alleviates Lipopolysaccharide-Induced Acute Kidney Injury via Suppressing Renal Inflammation and Ferroptosis in Mice

The nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome is a vital component of many inflammatory responses. Here, we intended to investigate the involvement of NLRP3 in lipopolysaccharide (LPS)-induced sepsis-associated acute kidney injury (S-AKI) and explore its mechanisms. For the first time, we validated elevated NLRP3 expression in the renal tissues of S-AKI patients by immunohistochemistry analysis. Through LPS injection in both wild-type and Nlrp3-/- mice, a S-AKI model was developed. It was found that LPS-induced kidney injury, including an abnormal morphology in a histological examination, abnormal renal function in a laboratory examination, and an increase in the expression of AKI biomarkers, was dramatically reversed in Nlrp3-deficient mice. Nlrp3 deletion alleviated renal inflammation, as evidenced by the suppression of the expression of pro-inflammatory cytokines and chemokines. A combinative analysis of RNA sequencing and the FerrDb V2 database showed that Nlrp3 knockout regulated multiple metabolism pathways and ferroptosis in LPS-induced S-AKI. Further qPCR coupled with Prussian blue staining demonstrated that Nlrp3 knockout inhibited murine renal ferroptosis, indicating a novel mechanism involving S-AKI pathogenesis by NLRP3. Altogether, the aforementioned findings suggest that Nlrp3 deficiency alleviates LPS-induced S-AKI by reducing renal inflammation and ferroptosis. Our data highlight that NLRP3 is a potential therapeutic target for S-AKI.

Penfluroidol Attenuates the Imbalance of the Inflammatory Response by Repressing the Activation of the NLRP3 Inflammasome and Reduces Oxidative Stress via the Nrf2/HO-1 Signaling Pathway in LPS-Induced Macrophages

Objectives

Excessive inflammatory responses and reactive oxygen species (ROS) formation play pivotal roles in the pathogenesis of sepsis. Penfluroidol (PF), an oral long-acting antipsychotic drug, has been suggested to possess diverse biological properties, including antischizophrenia, antitumour effect, and anti-inflammatory activity. The purpose of this research was to explore the anti-inflammatory and antioxidative effects of penfluroidol on lipopolysaccharide (LPS)-related macrophages.

Methods

The viability of RAW264.7 and THP-1 cells was measured by Enhanced Cell Counting Kit-8 (CCK-8). The production of nitric oxide was evaluated by the Nitric Oxide Assay Kit. The generation of pro-inflammatory monocytes was detected by qRT-PCR (quantitative real-time PCR) and ELISA (enzyme-linked immunosorbent assay). Oxidative stress was assessed by measuring ROS, malondialdehyde (MDA), and superoxide dismutase (SOD) activity. The protein expression of the Nrf2/HO-1/NLRP3 inflammasome was detected by western blotting.

Results

Our results indicated that no cytotoxic effect was observed when RAW264.7 and THP-1 cells were exposed to PF (0-1 μm) and/or LPS (1 μg/ml) for 24 hr. The data showed that LPS, which was repressed by PF, facilitated the generation of the pro-inflammatory molecules TNF-α and IL-6. In addition, LPS contributed to increased production of intracellular ROS compared with the control group, whereas the administration of PF effectively reduced LPS-related levels of ROS. Moreover, LPS induced the generation of MDA and suppressed the activities of SOD. However, PF treatment strongly decreased LPS-induced MDA levels and increased SOD activities in the RAW264.7 and THP-1 cells. Furthermore, our research confirmed that penfluroidol repressed the secretion of pro-inflammatory molecules by limiting the activation of the NLRP3 inflammasome and reducing oxidative effects via the Nrf2/HO-1 signaling pathway.

Conclusion

Penfluroidol attenuated the imbalance of the inflammatory response by suppressing the activation of the NLRP3 inflammasome and reduced oxidative stress via the Nrf2/HO-1 signaling pathway in LPS-induced macrophages.

Lung protective effect of Ticagrelor in endotoxemia

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. This study aimed to investigate the potential protective effect of the lungs in sepsis by modulating inflammatory and oxidative stress markers. Twenty-four adult male Swiss-albino mice, aged 8-12 weeks and weighing 20-30 g, were divided into four equal groups (n=6): sham (laparotomy only), CLP (laparotomy plus cecal ligation and puncture), vehicle (DMSO administered one hour before CLP), and Ticagrelor (50 mg/kg IP administered one hour before CLP). Tissue levels of pro-inflammatory and oxidative stress markers in the lung were assessed using ELISA. F2 isoprostane levels were significantly higher in the sepsis group (p<0.05) compared to the sham group, while Ticagrelor significantly decreased the inflammatory and oxidative stress markers compared to the sepsis group. All mice in the sepsis group had considerable (p=0.05) lung tissue damage, but Ticagrelor considerably decreased lung tissue injury (p=0.05). Furthermore, Ticagrelor was found to reduce tissue cytokine levels of the lung (IL-1, TNF a, IL-6, F2 isoprostane, GPR 17, MIF) in male mice during CLP-induced polymicrobial sepsis by modulation of pro-inflammatory and oxidative stress cascade signaling pathways.

Lutein attenuates Propionibacterium acnes-induced inflammation by inhibiting pyroptosis of human keratinocyte cells via TLR4/NLRP3/Caspase-1 pathway

BACKGROUND

Previous studies found Propionibacterium acnes (P. acnes) has a strong association with acne inflammation and cell pyroptosis. Because of the various side effects of current acne medicines, it is important to explore alternative drugs with anti-inflammatory activity against P. acnes. we explored the effect of Lutein on P. acnes-induced cell pyroptosis and accelerated the recovery of acne inflammation in vitro and vivo.

METHODS

Lutein was utilized to expose HaCaT keratinocytes, then we reassessed the effect of Lutein on the cell apoptosis, pyroptotic-associated inflammatory factors and catabolic enzymes in heat-killed P. acnes-treated HaCaT cells. Next, living P. acnes was intradermally injected into the right ears of ICR mice to induce mice with acne inflammation, and the effect of Lutein on living P. acnes-induced inflammation was investigated. Moreover, we explored the mechanism of Lutein on TLR4/NLRP3/Caspase-1 pathways by ELISA, immunofluorescence microscopy, and western blot assay.

RESULTS

Heat-killed P. acnes triggered remarkable cell pyroptosis, pyroptotic inflammatory factors and catabolic enzymes in HaCaT cells, including up-regulating interleukin (IL)-1β, IL-18, TNF-α, MMP3, MMP13, ADAMTS4, and ADAMTS5, TLR4, NLRP3, caspase-1, and the ratio of gasdermin D to cleaved gasdermin D, whereas these effects were suppressed by Lutein. In addition, Lutein effectively improved ear redness, swelling, and the expression of TLR4, IL-1β and TNF-α in vivo. Finally, NLRP3 activator (nigericin) increased caspase-1, IL-1β and IL-18 level, while TLR4 inhibitor (TAK-242) significantly blocked this effect in heat-killed P. acnes-treated cells.

CONCLUSIONS

Lutein attenuated P. acnes-caused pyroptosis of HaCaTs and the subsequent acne inflammation via the TLR4/NLRP3/Caspase-1 pathway.

The role of NLRP3 inflammasome in sepsis: A potential therapeutic target

Sepsis is the host immune imbalance following infection and leads to organ dysfunction, with highly complicated pathophysiology. To date, sepsis still lacks effective therapies with high mortality rates. Recently, numerous studies have highlighted the potential of NLRP3 inflammasome as a therapeutic target during sepsis. NLRP3 inflammasome is a protein complex that could induce the activation of caspase-1 and the following release of pro-inflammatory cytokines such as IL-1β and IL-18. It was demonstrated that NLRP3 inflammasome was involved in the development and progression of sepsis. In contrast, inhibition of NLRP3 inflammasome activation could mitigate the inflammatory response, protect organ function, and improve outcomes and mortality. This paper illustrated the activation pathways of the NLRP3 inflammasome and its possible molecular mechanisms in the pathophysiology of sepsis. Meanwhile, the beneficial effects of inhibiting NLRP3 activation in sepsis-related organ damage were also presented. In addition, the diverse role of NLRP3 inflammasome in bacterial clearance was addressed. Of note, several herbal extracts targeting NLRP3 inflammasome in the treatment of sepsis were emphasized. We hope that this paper could provide a basis for further drug research targeting NLRP3 inflammasome.

Inhibition of IGF2BP1 attenuates renal injury and inflammation by alleviating m6A modifications and E2F1/MIF pathway

Septic acute kidney injury (AKI) is characterized by inflammation. Pyroptosis often occurs during AKI and is associated with the development of septic AKI. This study found that induction of insulin-like growth factor 2 mRNA binding protein 1 (IGF2BP1) to a higher level can induce pyroptosis in renal tubular cells. Meanwhile, macrophage migration inhibitory factor (MIF), a subunit of NLRP3 inflammasomes, was essential for IGF2BP1-induced pyroptosis. A putative m6A recognition site was identified at the 3'-UTR region of E2F transcription factor 1 (E2F1) mRNA via bioinformatics analyses and validated using mutation and luciferase experiments. Further actinomycin D (Act D) chase experiments showed that IGF2BP1 stabilized E2F1 mRNA dependent on m6A. Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) indicated that E2F1 acted as a transcription factor to promote MIF expression. Thus, IGF2BP1 upregulated MIF through directly upregulating E2F1 expression via m6A modification. Experiments on mice with cecum ligation puncture (CLP) surgery verified the relationships between IGF2BP1, E2F1, and MIF and demonstrated the significance of IGF2BP1 in MIF-associated pyroptosis in vivo. In conclusion, IGF2BP1 was a potent pyroptosis inducer in septic AKI through targeting the MIF component of NLRP3 inflammasomes. Inhibiting IGF2BP1 could be an alternate pyroptosis-based treatment for septic AKI.

Protective mechanisms of Leontopodium leontopodioides extracts on lipopolysaccharide-induced acute kidney injury viathe NF-κB/NLRP3 pathway

Sepsis-induced uncontrolled systemic inflammatory response syndrome (SIRS) is a critical cause of multiple organ failure. Acute kidney injury (AKI) is one of the most serious complications associated with an extremely high mortality rate in SIRS, and it lacked simple, safe, and effective treatment strategies. Leontopodium leontopodioides (Willd.) Beauv (LLB) is commonly used in traditional Chinese medicine for the treatment of acute and chronic nephritis. However, it remains unclear whether lipopolysaccharide (LPS) affects LPS-induced AKI. To identify the molecular mechanisms of LLB in LPS-induced HK-2 cells and mice, LLB was prepared by extraction with 70% methanol, while a lipopolysaccharide (LPS)-induced HK-2 cell model and an AKI model were established in this study. Renal histopathology staining was performed to observe the morphology changes. The cell supernatant and kidney tissues were collected for determining the levels of inflammatory factors and protein expression by ELISA, immunofluorescence, and Western blot. The results indicated that LLB significantly reduced the expression of IL-6 and TNF-α in LPS-induced HK-2 cells, as well as the secretion of IL-6, TNF-α, and IL-1β in the supernatant. The same results were observed in LPS-induced AKI serum. Further studies revealed that LLB remarkably improved oxidative stress and apoptosis based on the content of MDA, SOD, and CAT in serum and TUNEL staining results. Notably, LLB significantly reduced the mortality due to LPS infection. Renal histopathology staining results supported these results. Furthermore, immunofluorescence and Western blot results confirmed that LLB significantly reduced the expression of the protein related to the NF-κB signaling pathway and NLRP3, ASC, and Caspase-1 which were significantly increased through LPS stimulation. These findings clearly demonstrated the potential use of LLB in the treatment of AKI and the crucial role of the NF-κB/NLRP3 pathway in the process through which LLB attenuates AKI induced by LPS.

Theacrine alleviates sepsis-induced acute kidney injury by repressing the activation of NLRP3/Caspase-1 inflammasome

Acute kidney injury (AKI) is a frequent and serious complication of sepsis, which results in a rapid decline of kidney function. Currently, there are no curative therapies for AKI. Theacrine is a purine alkaloid and exerts significant role in regulating inflammation, oxidative stress, and mood elevation. The study aims to evaluate the biological role and potential mechanism of theacrine in septic AKI. The murine and cellular models of septic AKI were established in lipopolysaccharide (LPS)-treated C57BL/6 mice and HK-2 cells, respectively. The effect of theacrine on alleviating septic AKI was assessed after pretreatment with theacrine in vivo and in vitro. We found that theacrine treatment significantly alleviated LPS-induced kidney injury, as evidenced by decreased levels of kidney injury markers (blood urea nitrogen and creatinine), inflammatory factors (IL-1β and IL-18), and cell apoptosis in vivo and in vitro. Mechanistically, theacrine markedly repressed the activation of NOD-like receptor (NLR) pyrin domain-containing protein 3 (NLRP3)inflammasome. As expected, MCC950 (a specific inhibitor of NLRP3) treatment also decreased LPS-induced production of IL-18 and IL-1β and cell apoptosis in HK-2 cells. More important, Nigericin sodiumsalt (a NLRP3 agonist) damaged the effect of theacrine on repressing kidney injury markers (blood urea nitrogen and creatinine), pro-inflammatory cytokines (IL-18 and IL-1β), and cell apoptosis. Taken together, these results demonstrate that theacrine alleviates septic AKI, at least in part by repressing the activation of NLRP3 inflammasome.

Cannabinoid receptor-2 attenuates neuroinflammation by promoting autophagy-mediated degradation of the NLRP3 inflammasome post spinal cord injury

Background

Neuroinflammation following spinal cord injury (SCI) results in prolonged neurological damage and locomotor dysfunction. Polarization of microglia is vital to regulation of neuroinflammation, although the underlying mechanisms have not yet been elucidated. Endocannabinoid receptor subtype 2 (CB2R) is reported to ameliorate neurodegeneration via immunomodulation activities. However, the underlying machinery in the context of SCI remains unclear.

Methods

A lipopolysaccharide-induced microglia inflammation model and a mouse model of SCI were employed to investigate the regulatory role of CB2R in the polarization of microglia in response to excess neuroinflammation. Markers of inflammation and autophagy were measured by Western blot analysis, immunofluorescence, flow cytometry, and enzyme-linked immunosorbent assays. Histological staining with hematoxylin and eosin, Nissl, and Luxol^® fast blue was conducted using commercial kits. The locomotor function of the hindlimbs of the experimental mice was evaluated with the Basso Mouse Scale, Louisville Swim Scale, and footprint assay.

Results

The results showed that CB2R promoted M2 differentiation, increased interleukin (IL)-10 expression, and inhibited M1 differentiation with decreased expression of IL-1β and IL-6. CB2R activation also increased ubiquitination of the NLRP3 inflammasome and interacted with the autophagy-related proteins p62 and microtubule-associated proteins 1B light chain 3. Treatment with the CB2R activator JWH-133 reduced loss of myelin, apoptosis of neurons, and glial scarring, leading to improved functional recovery of the hindlimbs, while the CB2R antagonist AM630 produced opposite results.

Conclusion

Taken together, these results suggested that CB2R activation attenuated neuroinflammation targeting microglial polarization by promoting NLRP3 clearance, thereby facilitating functional recovery post-SCI.

Sepsis-induced AKI: From pathogenesis to therapeutic approaches

Sepsis is a heterogenous and highly complex clinical syndrome, which is caused by infectious or noninfectious factors. Acute kidney injury (AKI) is one of the most common and severe complication of sepsis, and it is associated with high mortality and poor outcomes. Recent evidence has identified that autophagy participates in the pathophysiology of sepsis-associated AKI. Despite the use of antibiotics, the mortality rate is still at an extremely high level in patients with sepsis. Besides traditional treatments, many natural products, including phytochemicals and their derivatives, are proved to exert protective effects through multiple mechanisms, such as regulation of autophagy, inhibition of inflammation, fibrosis, and apoptosis, etc. Accumulating evidence has also shown that many pharmacological inhibitors might have potential therapeutic effects in sepsis-induced AKI. Hence, understanding the pathophysiology of sepsis-induced AKI may help to develop novel therapeutics to attenuate the complications of sepsis and lower the mortality rate. This review updates the recent progress of underlying pathophysiological mechanisms of sepsis-associated AKI, focuses specifically on autophagy, and summarizes the potential therapeutic effects of phytochemicals and pharmacological inhibitors.

Macrophage migration inhibitory factor in acute kidneyinjury

Acute kidney injury (AKI) is a complex clinical syndrome with multiple etiologies and pathogenesis, which lacks early biomarkers and targeted therapy. Recently, macrophage migration inhibitory factor (MIF) family protein have received increasing attention owing to its pleiotropic protein molecule character in acute kidney injury, where it performed a dual role in the pathological process. macrophage migration inhibitory factor and macrophage migration inhibitory factor-2 are released into the peripheral circulation when Acute kidney injury occurs and interact with various cellular pathways. On the one hand, macrophage migration inhibitory factor exerts a protective effect in anti-oxidation and macrophage migration inhibitory factor-2 promotes cell proliferation and ameliorates renal fibrosis. On the other hand, macrophage migration inhibitory factor aggravates renal injury as an upstream inflammation factor. Herein, we provide an overview on the biological role and possible mechanisms of macrophage migration inhibitory factor and macrophage migration inhibitory factor-2 in the process of Acute kidney injury and the clinical application prospects of macrophage migration inhibitory factor family proteins as a potential therapeutic target.

Cytoglobin Silencing Promotes Melanoma Malignancy but Sensitizes for Ferroptosis and Pyroptosis Therapy Response

Despite recent advances in melanoma treatment, there are still patients that either do not respond or develop resistance. This unresponsiveness and/or acquired resistance to therapy could be explained by the fact that some melanoma cells reside in a dedifferentiated state. Interestingly, this dedifferentiated state is associated with greater sensitivity to ferroptosis, a lipid peroxidation-reliant, iron-dependent form of cell death. Cytoglobin (CYGB) is an iron hexacoordinated globin that is highly enriched in melanocytes and frequently downregulated during melanomagenesis. In this study, we investigated the potential effect of CYGB on the cellular sensitivity towards (1S, 3R)-RAS-selective lethal small molecule (RSL3)-mediated ferroptosis in the G361 melanoma cells with abundant endogenous expression. Our findings show that an increased basal ROS level and higher degree of lipid peroxidation upon RSL3 treatment contribute to the increased sensitivity of CYGB knockdown G361 cells to ferroptosis. Furthermore, transcriptome analysis demonstrates the enrichment of multiple cancer malignancy pathways upon CYGB knockdown, supporting a tumor-suppressive role for CYGB. Remarkably, CYGB knockdown also triggers activation of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome and subsequent induction of pyroptosis target genes. Altogether, we show that silencing of CYGB expression modulates cancer therapy sensitivity via regulation of ferroptosis and pyroptosis cell death signaling pathways.

Molecular mechanisms and functions of pyroptosis in sepsis and sepsis-associated organ dysfunction

Sepsis, a life-threatening organ dysfunction caused by a dysregulated host response to infection, is a leading cause of death in intensive care units. The development of sepsis-associated organ dysfunction (SAOD) poses a threat to the survival of patients with sepsis. Unfortunately, the pathogenesis of sepsis and SAOD is complicated, multifactorial, and has not been completely clarified. Recently, numerous studies have demonstrated that pyroptosis, which is characterized by inflammasome and caspase activation and cell membrane pore formation, is involved in sepsis. Unlike apoptosis, pyroptosis is a pro-inflammatory form of programmed cell death that participates in the regulation of immunity and inflammation. Related studies have shown that in sepsis, moderate pyroptosis promotes the clearance of pathogens, whereas the excessive activation of pyroptosis leads to host immune response disorders and SAOD. Additionally, transcription factors, non-coding RNAs, epigenetic modifications and post-translational modifications can directly or indirectly regulate pyroptosis-related molecules. Pyroptosis also interacts with autophagy, apoptosis, NETosis, and necroptosis. This review summarizes the roles and regulatory mechanisms of pyroptosis in sepsis and SAOD. As our understanding of the functions of pyroptosis improves, the development of new diagnostic biomarkers and targeted therapies associated with pyroptosis to improve clinical outcomes appears promising in the future.