The gut microbiome has been closely linked to obstructive sleep apnea (OSA)-associated hypertension (HTN). However, its precise role in the pathogenesis of OSA-induced HTN remains unclear.

To clarify the causal relationship between gut dysbiosis and OSA-related HTN, C57BL6J mice were randomly assigned to four groups. Each group underwent fecal microbiota transplantation from healthy individuals (control), OSA patients (OSA group), OSA patients with pre-hypertension (OSA-pHTN group), or OSA patients with HTN (OSA-HTN group). The pro-hypertensive effects of the OSA gut microbiota were verified, and the composition and function of the gut microbiota were compared using 16S rDNA gene sequencing. Additionally, the gut microbiota-related lipopolysaccharide (LPS)/ Toll-like receptor 4 (TLR4)/nuclear factor-kappaB (NF-κB) pathway in aortic tissues was investigated.

Fecal microbiota transplantation induced increased systolic blood pressure and aortic injury in mice from the OSA, OSA-pHTN and OSA-HTN groups, whereas no significant injury was observed in the control group. These three groups exhibited dysbiosis and impaired intestinal barrier function as evidenced by a reduction in Akkermansia and decreased expression of zonula occludens-1 and Occludin proteins. In addition, LPS, TLR4 and phosphorylated NF-κB expression were increased in aortic tissue from the three groups, and immunofluorescence showed a significant upregulation of TLR4 expression in aortic endothelial cells compared to controls.

This study demonstrates the pro-hypertensive effects of gut microbiota in OSA, mediated through the gut-derived LPS/TLR4/NF-κB pathway. These findings may guide the development of therapeutic strategies focused on restoring gut microbiome homeostasis.

Intestinal epithelial-derived IL-18 is critical for homeostatic intestinal barrier function and is secreted through Gasdermin D (GSDMD) pores. Inflammasome activation is a prerequisite for both IL-18 maturation and GSDMD pore formation. However, GSDMD pores also cause pyroptotic cell death, which could be detrimental to the intestinal epithelial barrier. How epithelial cells balance the need to secrete IL-18 and to maintain barrier integrity remains poorly understood. In human intestinal epithelial cell lines and in primary human epithelial intestinal organoids, but not in immune cells, GSDMD plasma membrane pore formation by LPS electroporation and by gram-negative bacterial infection induced a non-conventional p37 caspase-4 fragment that was associated with reduced levels of mature IL-18. By contrast, limiting GSDMD plasma membrane pores pharmacologically and via point-mutagenesis prevented caspase-4 cleavage and increased IL-18 production, suggesting that p37 caspase-4 cleavage may regulate IL-18 maturation in the intestinal epithelium. In support, co-expression of caspase-4 cleavage mutants and IL-18 in HEK293T cells revealed that non-cleavable caspase-4 produced more mature IL-18 than cleaved caspase-4. Overall, these studies suggest that epithelial inflammasomes encode feedback pathways that control the balance between cytokine secretion and cell death. This may be an important mechanism to ensure homeostatic IL-18 production in the intestinal epithelium.

Differences in skin and hair phenotypes between the scapular and ventral regions of yaks (Bos grunniens) are obvious and become more prominent with age. However, the genetic mechanism that causes differences in yak skin at different ages has not been reported. In this study, we investigated the transcriptomic profile of yak skin across different ages (0.5 years, 2.5 years, and 4.5 years) and body sites (scapular and ventral regions). Differential gene expression analysis was initially conducted to explore the transcriptomic differences in skin at different ages and different body sites. Subsequently, weighted gene co-expression network analysis (WGCNA) was employed to analyze the transcriptomic data comprehensively. The results showed that, among all comparison groups, the Y2.5_S vs. Y2.5_V group (regional comparison) exhibited the highest number of DEGs, with 491 genes (179 upregulated and 312 downregulated), followed by the Y2.5_V vs. Y0.5_V group (age comparison), which had 370 DEGs (103 upregulated and 267 downregulated). DEGs such as IGF2BP3, ADCY8, FOSL1, and S100A8 were found in all comparison groups of different ages, and multiple members of the HOX gene family including HOXC10, HOXA9, HOXA6, HOXB9, and HOXB6 were differentially expressed in comparison groups at different sites. Functional enrichment analysis showed that there were more obvious differences in immune function between different ages of skin and more obvious differences in endocrine function between different parts of skin. WGCNA revealed that genes related with immunity such as GLYATL2, ACSL5, and SPDEF were the core genes of the co-expression module associated with the scapula region, and multiple genes related to hair follicle development such as FOXN1, OVOL1, DLX3, HOXC13, and TCHH were found to be the hub genes of the co-expression module associated with the ventral region. Overall, our study provides valuable insights into the transcriptomic complexity of yak skin across different ages and body sites. The differential gene expression patterns and co-expression network modules identified in this study lay the foundation for further research on skin biology and adaptation mechanisms in yaks.

Pyroptosis is a type of programmed inflammatory cell death characterized by balloon-like swelling, membrane rupture, and the release of inflammatory cytokines and danger signals. Pyroptosis is directly triggered by activated gasdermins (GSDMs) which bind to membrane phospholipids, oligomerize, and form pores in cell membranes. GSDM activation is mediated by various effector proteases via cleavage of the linker region or post-translational modification to release the active N-terminal fragment in response to a variety of pathogenic or intrinsic danger signals. GSDM-mediated pyroptosis is involved in the pathogenesis of an array of infectious and inflammatory diseases and cancers. This review discusses recent advances related to the physiological and pathological functions of GSDM-mediated pyroptosis, as well as therapeutic strategies targeting pyroptosis.

Pyroptosis, a novel mode of inflammatory cell death, is executed by membrane pore-forming gasdermin (GSDM) family members in response to extracellular or intracellular injury cues and is characterized by a ballooning cell morphology, plasma membrane rupture and the release of inflammatory mediators such as interleukin-1β (IL-1β), IL-18 and high mobility group protein B1 (HMGB1). It is a key effector mechanism for host immune defence and surveillance against invading pathogens and aberrant cancerous cells, and contributes to the onset and pathogenesis of inflammatory and autoimmune diseases. Manipulating the pore-forming activity of GSDMs and pyroptosis could lead to novel therapeutic strategies. In this Review, we discuss the current knowledge regarding how GSDM-mediated pyroptosis is initiated, executed and regulated, its roles in physiological and pathological processes, and the crosstalk between different modes of programmed cell death. We also highlight the development of drugs that target pyroptotic pathways for disease treatment.

Gasdermin D (GSDMD) has garnered significant attention primarily for the pore-forming role of its p30 N-terminal fragment (NT-p30) generated during pyroptosis, a proinflammatory form of cell death. However, emerging evidence suggests that the formation of GSDMD-NT pores is reversible, and the activation of GSDMD does not necessarily lead to pyroptosis. Instead, this process may take part either in other forms of cell death, or in various state changes of living cells, including (i) inflammation regulation, (ii) endolysosomal pathway rewiring, (iii) granule exocytosis, (iv) type II immunity, (v) food tolerance maintenance, and (vi) temporary permeability alteration. This review explores the latest insights into the involvement of GSDMD in cell death and homeostasis maintenance, aiming to underscore the pleiotropic nature of GSDMD.

Pyroptosis is a unique form of programmed cell death characterized by intense inflammation. It involves the activation of Gasdermin proteins, which form membrane pores, leading to rapid cell rupture and the release of inflammatory molecules. Unlike other types of cell death, pyroptosis has distinct activation mechanisms and plays a complex role in chronic intestinal diseases, including inflammatory bowel disease, intestinal fibrosis, chronic infectious enteritis, and colorectal cancer. This review comprehensively examines how pyroptosis influences disease development and progression while exploring the therapeutic potential of targeting pyroptosis-related pathways. Moreover, the complex interplay between gut microbiota and pyroptosis is summarized, highlighting its critical role in the pathogenesis of chronic intestinal disorders. A deeper understanding of pyroptosis-related mechanisms in these diseases may provide valuable insights for future research and contribute to the development of innovative therapeutic strategies in gastroenterology.

Glycyrrhiza uralensis Fisch. is a medicinal herb that can be added to food to provide therapeutic effects and reduce the burden of medications. Herein, the immunomodulatory effects of Glycyrrhiza polysaccharides (GPs) were verified and illustrated by intervening immunocompromised rats treated with different doses of GPs, which were reflected for adjusting the composition and structure of the intestinal microbiota and altering the metabolic profile. The immunomodulatory effects of GPs were exerted by regulating the intestinal microenvironment. In particular, GPs could promote the growth of probiotic bacteria Allobaculum, norank__o_Clostridia_UCG-014, Dubosiella, and g__norank_o___RF39 and curb the growth of harmful bacteria Enterococcus. The results showed that GPs had a prebiotic effect, which contributed to improving the intestinal environment and maintaining intestinal health. In addition, the content of beneficial differential metabolites was up-regulated, especially short-chain fatty acids, with alanine, aspartate, and glutamate metabolism; arginine biosynthesis; glyoxylate and dicarboxylate metabolism being the most enriched pathways. These metabolic pathways imply the metabolic process of GPs, and the metabolic pathways and differential effector metabolites of it are focused. Overall, the purpose of this article lies in providing support for the application of GPs for regulating immune function.

Pyroptosis is a regulated form of inflammatory cell death in which Gasdermin D (GSDMD) plays a central role as the key effector molecule. GSDMD-mediated pyroptosis is characterized by complex biological features and considerable heterogeneity in its expression, mechanisms, and functional outcomes across various tissues, cell types, and pathological microenvironments. This heterogeneity is particularly pronounced in inflammation-related diseases and tumors. In the context of inflammatory diseases, GSDMD expression is typically upregulated, and its activation in macrophages, neutrophils, T cells, epithelial cells, and mitochondria triggers both pyroptotic and non-pyroptotic pathways, leading to the release of pro-inflammatory cytokines and exacerbation of tissue damage. However, under certain conditions, GSDMD-mediated pyroptosis may also serve a protective immune function. The expression of GSDMD in tumors is regulated in a more complex manner, where it can either promote immune evasion or, in some instances, induce tumor cell death. As our understanding of GSDMD's role continues to progress, there have been advancements in the development of inhibitors targeting GSDMD-mediated pyroptosis; however, these therapeutic interventions remain in the preclinical phase. This review systematically examines the cellular and molecular complexities of GSDMD-mediated pyroptosis, with a particular emphasis on its roles in inflammation-related diseases and cancer. Furthermore, it underscores the substantial therapeutic potential of GSDMD as a target for precision medicine, highlighting its promising clinical applications.

Impaired intestinal epithelial barrier has been considered to be associated with an increasing variety of gastrointestinal diseases, especially inflammatory bowel disease (IBD) encompassing Crohn's disease (CD) and ulcerative colitis (UC). We aimed to investigate the role of Gasdermin B (GSDMB) in modulating intestinal epithelial barrier integrity and proposed a promising therapeutic strategy.

Gasdermin B expression was evaluated in adult CD samples by molecular biology means and single-cell transcriptomes. We generated GSDMB (Rosa26-lsl/lsl-GSDMB;Villin-Cre) and one of its functional missense variant rs2305480 (Rosa26-lsl/lsl-GSDMB-MU;Villin-Cre) intestinal epithelial-specific knock in mice to observe the functions of GSDMB in intestinal epithelial barrier. RNA-seq analysis as well as human and murine intestine-derived organoids were used to determine the pathogenic mechanism of GSDMB.

The expression of GSDMB was increased during active intestinal inflammation and principally localized in intestinal epithelial cells (IECs). Rosa26-lsl/lsl-GSDMB;Villin-Cre mice developed enterocolitis and exhibited aberrant intestinal barrier integrity. Mechanistically, epithelial GSDMB modulated hyperactive unfolded protein response of IECs by up-regulating BHLHA15 to mediate intestinal barrier injury. Rosa26-lsl/lsl-GSDMB-MU;Villin-Cre mice with the mutant rs2305480 of GSDMB aggravated such inflammatory effects.

We have uncovered an important and previously unrecognized role of GSDMB in intestinal homeostasis, which represents a potential therapeutic target for intestinal inflammation.

Reactive oxygen species (ROS) production and inflammasome activation are the key components of the innate immune response to microbial infection and sterile insults. ROS are at the intersection of inflammation and immunity during cancer development. Balanced regulation of ROS production and inflammasome activation serves as the central hub of innate immunity, determining whether a cell will survive or undergo cell death. However, the mechanisms underlying this balanced regulation remain unclear. Mitochondria and NADPH oxidases are the two major sources of ROS production. Recently, NCF4, a component of the NADPH oxidase complex that primarily contributes to ROS generation in phagocytes, was reported to balance ROS production and inflammasome activation in macrophages. The phosphorylation and puncta distribution of NCF4 shifts from the membrane-bound NADPH complex to the perinuclear region, promoting ASC speck formation and inflammasome activation, which triggers downstream IL-18-IFN-γ signaling to prevent the progression of colorectal cancer (CRC). Here, we review ROS signaling and inflammasome activation studies in colitis-associated CRC and propose that NCF4 acts as a ROS sensor that balances ROS production and inflammasome activation. In addition, NCF4 is a susceptibility gene for Crohn's disease (CD) and CRC. We discuss the evidence demonstrating NCF4's crucial role in facilitating cell-cell contact between immune cells and intestinal cells, and mediating the paracrine effects of inflammatory cytokines and ROS. This coordination of the signaling network helps create a robust immune microenvironment that effectively prevents epithelial cell mutagenesis and tumorigenesis during the early stage of colitis-associated CRC.

Gasdermin D (GSDMD) is a key effector molecule that activates pyroptosis through its N terminal domain (GSDMD-NT). However, the roles of GSDMD in colorectal cancer (CRC) have not been fully explored. The role of the full-length GSDMD (GSDMD-FL) is also not clear. In this study, we observed that GSDMD modulates CRC progression through other mechanisms in addition to activating GSDMD-NT.

Clinical CRC samples and human-derived CRC cell lines were used in this study. GSDMD expression was evaluated by RT-qPCR, Western blot and immunohistochemical (IHC) analysis. GSDMD knockdown and overexpression stable cell lines were established by Lentiviral transduction. CCK-8 assay, flow cytometry analysis for cell cycle, Transwell assay, and cell scratch assay were performed in vitro to explore the impact of GSDMD on CRC progression. Mouse subcutaneous transplantation tumor models were constructed to assess the role of GSDMD in vivo. Intestinal epithelial cell (IEC)-specific knockout of Gsdmd mice (GsdmdΔIEC) was used to evaluate the effect of GSDMD on intestinal adenoma formation in AOM-DSS and Apcmin/+ mouse models. RNA sequencing was performed to explore the regulatory pathways associated with the role of GSDMD in CRC cells. Co-Immunoprecipitation (CO-IP), Western blot and immunofluorescence (IF) were conducted to investigate the interactions between GSDMD and EGFR. Exogenous addition of Gefitinib was used to evaluate the effect of GSDMD on autophosphorylation of EGFR at the Tyr1068 site.

GSDMD was highly expressed in clinical CRC tissues and human-derived CRC cell lines. GSDMD knockdown inhibited the viability, cell cycle changes, invasion ability and migration ability of CRC cell lines in vitro and vivo, whereas GSDMD overexpression had the opposite effects. Intestinal adenoma development was reduced in GsdmdΔIEC mice in both AOM-DSS and Apcmin/+ mouse models. GSDMD-FL interacted with EGFR and promoted CRC progression by inducing autophosphorylation of EGFR at the Tyr1068 site, subsequently activating ERK1/2. Exogenous Gefitinib abrogated the tumorigenic properties of GSDMD.

GSDMD-FL promotes CRC progression by inducing EGFR autophosphorylation at the Tyr1068 site, subsequently activating the downstream ERK1/2. Inhibition of GSDMD is a potential strategy for the treatment of colorectal cancer.

Alcoholic liver disease (ALD) patients with bacterial infections usually exhibit high mortality rates. Infections frequently involve bacteria such as Vibrio vulnificus and Enterococcus faecalis. Nevertheless, the mechanisms predisposing ALD patients to bacterial infections and the role of the NLRP3 inflammasome in the intestinal epithelial barrier in ALD remain unclear.

We established ALD mice models of WT, Nlrp3-/- and Gsdmd-/- through chronic alcohol consumption feeding and acute alcohol induction. We compared alterations in gut microbiota, ileitis, and adhesion protein expression, to analyze the role and potential mechanism of NLRP3 in the early onset of ALD. Concurrently, we examined the changes in inflammation and liver damage in the ileum of ALD and healthy mice following foodborne infection with V. vulnificus.

Compared with the control group, the expression levels of ZO-1, Claudin-1 and E-cadherin were reduced in the ileum of ALD mice, while those of NLRP3, caspase-1(p20), GSDMD-N and IL-1β were elevated. Nlrp3-/- and Gsdmd-/- ALD mice showed an increased gut bacterial load, decreased ileal expression of E-cadherin, more severe ileitis, pronounced liver damage, steatosis and higher plasma levels of FITC-dextran, D-LA and ZO-1 compared with WT mice. Notably, Nlrp3-/- ALD mice exhibited a higher presence of Deferribacterota and Enterobacteriaceae. Furthermore, ALD mice infected with V. vulnificus infection exhibited no further activation of NLRP3 in the ileum, leading to increased intestinal permeability and bloodstream infections.

This study indicated that NLRP3 activation in the ileum of ALD mice stabilizes the inflammation-related gut microbiota, preserves the intestinal epithelial barrier, and diminishes inflammation and liver injury. Furthermore, the compromised immune defence in ALD mice may contribute to their heightened susceptibility to bacterial pathogens.

Activation of the NLRP3-GSDMD pathway in the ileum of Alcoholic liver disease (ALD) mice. NLRP3 activation maintains homeostasis of gut microbiota and intestinal epithelial barrier in ALD mice. ALD mice infected with V. vulnificus infection exhibited no further activation of NLRP3 in the ileum, leading to increased intestinal permeability and bloodstream infections.

Human milk contains extracellular vesicles (EVs) that carry bioactive molecules such as microRNA, to the newborn intestine. The downstream effects of EV cargo on signaling and immune modulation may shield neonates against inflammatory diseases, including necrotizing enterocolitis. Premature infants are especially at risk, while human milk-feeding may offer protection. The effect of gestational-age specific term and preterm EVs from transitional human milk was characterized on human intestinal epithelial cells (HIECs and Caco-2), primary macrophages, and THP-1 monocytes. We hypothesized that term and preterm EVs differentially influence immune-related cytokines and cell death. We found that preterm EVs were enriched in CD14 surface marker, while both term and preterm EVs increased epidermal growth factor secretion. Following inflammatory stimuli, only term EVs inhibited secretion of IL-6 in HIECs, and reduced expression of pro-inflammatory cytokine IL-1β in macrophages. Term and preterm EVs inhibited secretion of IL-1β and reduced inflammasome related cell death. We proposed that human milk EVs regulate immune-related signaling via their conserved microRNA cargo, which could promote tolerance and a homeostatic immune response. These findings provide basis for further studies into potential therapeutic supplementation with EVs in vulnerable newborn populations by considering functional, gestational age-specific effects. IMPACT: This study reveals distinct functional differences between term and preterm transitional human milk extracellular vesicles (EVs) highlighting the importance of gestational age in their bioactivity. Term EVs uniquely inhibited IL-6 secretion, IL-1β expression, and apoptosis following inflammatory stimuli. Both term and preterm human milk EVs reduced IL-1β secretion and inflammasome-induced cell death. Conserved human milk extracellular vesicle microRNA cargo could be a mediator of the anti-inflammatory effects, particularly targeting cytokine production, the inflammasome, and programmed cell death. These findings underscore the importance of considering gestational age in future research exploring the therapeutic potential of human milk extracellular vesicles to prevent or treat intestinal inflammatory diseases in neonates.

Dysregulated metabolism, cell death, and inflammation contribute to the development of metabolic dysfunction-associated steatohepatitis (MASH). Pyroptosis, a recently identified form of programmed cell death, is closely linked to inflammation. However, the precise role of pyroptosis, particularly gasdermin-E (GSDME), in MASH development remains unknown. In this study, we observed GSDME cleavage and GSDME-associated interleukin-1β (IL-1β)/IL-18 induction in liver tissues of MASH patients and MASH mouse models induced by a choline-deficient high-fat diet (CDHFD) or a high-fat/high-cholesterol diet (HFHC). Compared with wild-type mice, global GSDME knockout mice exhibited reduced liver steatosis, steatohepatitis, fibrosis, endoplasmic reticulum stress, lipotoxicity and mitochondrial dysfunction in CDHFD- or HFHC-induced MASH models. Moreover, GSDME knockout resulted in increased energy expenditure, inhibited intestinal nutrient absorption, and reduced body weight. In the mice with GSDME deficiency, reintroduction of GSDME in myeloid cells-rather than hepatocytes-mimicked the MASH pathologies and metabolic dysfunctions, as well as the changes in the formation of neutrophil extracellular traps and hepatic macrophage/monocyte subclusters. These subclusters included shifts in Tim4+ or CD163+ resident Kupffer cells, Ly6Chi pro-inflammatory monocytes, and Ly6CloCCR2loCX3CR1hi patrolling monocytes. Integrated analyses of RNA sequencing and quantitative proteomics revealed a significant GSDME-dependent reduction in citrullination at the arginine-114 (R114) site of dynamin-related protein 1 (Drp1) during MASH. Mutation of Drp1 at R114 reduced its stability, impaired its ability to redistribute to mitochondria and regulate mitophagy, and ultimately promoted its degradation under MASH stress. GSDME deficiency reversed the de-citrullination of Drp1R114, preserved Drp1 stability, and enhanced mitochondrial function. Our study highlights the role of GSDME in promoting MASH through regulating pyroptosis, Drp1 citrullination-dependent mitochondrial function, and energy balance in the intestine and liver, and suggests that GSDME may be a potential therapeutic target for managing MASH.

The small intestine contains a two-front nutrient supply environment created by luminal dietary and microbial metabolites (enteral side) and systemic metabolites from the host (serosal side). Yet, it is unknown how each side contributes differentially to the small intestinal physiology. Here, we generated a comprehensive, high-resolution map of the small intestinal two-front nutrient supply environment. Using in vivo tracing of macronutrients and spatial metabolomics, we visualized the spatiotemporal dynamics and cell-type tropism in nutrient absorption and the region-specific metabolic heterogeneity within the villi. Specifically, glutamine from the enteral side fuels goblet cells to support mucus production, and the serosal side loosens the epithelial barrier by calibrating fungal metabolites. Disorganized feeding patterns, akin to the human lifestyle of skipping breakfast, increase the risk of metabolic diseases by inducing epithelial memory of lipid absorption. This study improves our understanding of how the small intestine is spatiotemporally regulated by its unique nutritional environment.

Long-term consumption of swainsonine could be poisonous to livestock, including facilitating apoptosis by impairing lysosomal function and inhibiting autophagic degradation, leading to liver inflammation and even death in livestock. However, the mechanism by swainsonine induced systemic inflammatory responses remained unclear, especially the effects of swainsonine on intestinal permeability, lipopolysaccharide (LPS) level and oxidative stress response were unknown. In this study, swainsonine increased intestinal permeability as evidenced by the significant down-regulation of colonic goblet cells, Akkermansia muciniphila and intestinal tight junction protein Occludin, Claudin 1 and ZO-1, and the significant up-regulation of mRNA expression level of the intestinal permeability indicator protein tyrosine phosphatase receptor type H (Ptprh) in the ileum of mice. Simultaneously, the elevated LPS biosynthetic genes in intestinal microbiota and increased intestinal permeability facilitated more bacterial endotoxin LPS to enter the blood. High concentration of free-form LPS induced high levels of proinflammatory cytokines and oxidative stress response, thereby causing the systemic inflammation. These findings provided a new perspective on swainsonine-induced systemic inflammation, suggesting that intestinal permeability and free-form LPS level may be the potential trigger factors.

Cell death is a central process for organismal health. Pyroptosis, namely pyroptotic cell death, is recognized as a critical type that disrupts membrane and triggers pro-inflammatory cytokine secretion via gasdermins, providing a robust form of cytolysis. Meanwhile, along with the thorough research, a great deal of evidence has demonstrated the dual effects of pyroptosis in host defense and inflammatory diseases. More importantly, the recent identification of abundant gasdermin-like proteins in bacteria and fungi suggests an ancient origin of pyroptosis-based regulated cell death in the life evolution. In this review, we bring a general overview of pyroptosis pathways focusing on gasdermin structural biology, regulatory mechanisms, and recent progress in induction and inhibition strategies for disease treatment. We look forward to providing an insightful perspective for readers to comprehend the frame and challenges of the pyroptosis field, and to accelerating its clinical application.

The establishment of an early pro-regenerative niche is crucial for tissue regeneration1,2. Gasdermin D (GSDMD)-dependent pyroptosis accounts for the release of inflammatory cytokines upon various insults3-5. However, little is known about its role in tissue regeneration followed by homeostatic maintenance. Here we show that macrophage GSDMD deficiency delays tissue recovery but has little effect on the local inflammatory milieu or the lytic pyroptosis process. Profiling of the metabolite secretome of hyperactivated macrophages revealed a non-canonical metabolite-secreting function of GSDMD. We further identified 11,12-epoxyeicosatrienoic acid (11,12-EET) as a bioactive, pro-healing oxylipin that is secreted from hyperactive macrophages in a GSDMD-dependent manner. Accumulation of 11,12-EET by direct supplementation or deletion of Ephx2, which encodes a 11,12-EET-hydrolytic enzyme, accelerated muscle regeneration. We further demonstrated that EPHX2 accumulated within aged muscle, and that consecutive 11,12-EET treatment rejuvenated aged muscle. Mechanistically, 11,12-EET amplifies fibroblast growth factor signalling by modulating liquid-liquid phase separation of fibroblast growth factors, thereby boosting the activation and proliferation of muscle stem cells. These data depict a GSDMD-guided metabolite crosstalk between macrophages and muscle stem cells that governs the repair process, which offers insights with therapeutic implications for the regeneration of injured or aged tissues.

Pyroptosis is a type of programmed cell death characterized by cell swelling and osmotic lysis, resulting in cytomembrane rupture and release of immunostimulatory components, which play a role in several pathological processes. Significant cellular responses to various stimuli involve the formation of inflammasomes, maturation of inflammatory caspases, and caspase-mediated cleavage of gasdermin. The function of pyroptosis in disease is complex but not a simple angelic or demonic role. While inflammatory diseases such as sepsis are associated with uncontrollable pyroptosis, the potent immune response induced by pyroptosis can be exploited as a therapeutic target for anti-tumor therapy. Thus, a comprehensive review of the role of pyroptosis in disease is crucial for further research and clinical translation from bench to bedside. In this review, we summarize the recent advancements in understanding the role of pyroptosis in disease, covering the related development history, molecular mechanisms including canonical, non-canonical, caspase 3/8, and granzyme-mediated pathways, and its regulatory function in health and multiple diseases. Moreover, this review also provides updates on promising therapeutic strategies by applying novel small molecule inhibitors and traditional medicines to regulate pyroptosis. The present dilemmas and future directions in the landscape of pyroptosis are also discussed from a clinical perspective, providing clues for scientists to develop novel drugs targeting pyroptosis.

The gasdermins are a family of pore-forming proteins that have recently emerged as executors of pyroptosis, a lytic form of cell death that is induced by the innate immune system to eradicate infected or malignant cells. Mammalian gasdermins comprise a cytotoxic N-terminal domain, a flexible linker and a C-terminal repressor domain. Proteolytic cleavage in the linker releases the cytotoxic domain, thereby allowing it to form β-barrel membrane pores. Formation of gasdermin pores in the plasma membrane eventually leads to a loss of the electrochemical gradient, cell death and membrane rupture. Here we review recent work that has expanded our understanding of gasdermin biology and function in mammals by revealing their activation mechanism, their regulation and their roles in autoimmunity, host defence and cancer. We further highlight fungal and bacterial gasdermin pore formation pointing to a conserved mechanism of cell death induction.

Inflammatory diseases compromise a clinically common and diverse group of conditions, causing detrimental effects on body functions. Gasdermins (GSDM) are pore-forming proteins, playing pivotal roles in modulating inflammation. Belonging to the GSDM family, gasdermin D (GSDMD) actively mediates the pathogenesis of inflammatory diseases by mechanistically regulating different forms of cell death, particularly pyroptosis, and cytokine release, in an inflammasome-dependent manner. Aberrant activation of GSDMD in different types of cells, such as immune cells, cardiovascular cells, pancreatic cells and hepatocytes, critically contributes to the persistent inflammation in different tissues and organs. The contributory role of GSDMD has been implicated in diabetes mellitus, liver diseases, cardiovascular diseases, neurodegenerative diseases, and inflammatory bowel disease (IBD). Clinically, alterations in GSDMD levels are potentially indicative to the occurrence and severity of diseases. GSDMD inhibition might represent an attractive therapeutic direction to counteract the progression of inflammatory diseases, whereas a number of GSDMD inhibitors have been shown to restrain GSDMD-mediated pyroptosis through different mechanisms. This review discusses the current understanding and future perspectives on the role of GSDMD in the development of inflammatory diseases, as well as the clinical insights of GSDMD alterations, and therapeutic potential of GSDMD inhibitors against inflammatory diseases. Further investigation on the comprehensive role of GSDM shall deepen our understanding towards inflammation, opening up more diagnostic and therapeutic opportunities against inflammatory diseases.

Naphthenic acids (NAs) are important pollutants in marine crude oils and have obvious toxic effects on marine organisms. However, the effects of NAs on the intestine are largely unknown. Thus, we evaluated the effects of NAs exposure in the intestines of marine medaka. Fish were experimentally exposed to NAs (0.5 mg/L, 5 mg/L, and 10 mg/L) for 96 h and monitored for changes in intestinal histology, markers of oxidative stress, and intestinal microbiome responses. Significant mucosal damage, inflammation, and oxidative stress were observed in the intestines of marine medaka after exposure to NAs. In addition, significant changes in the gut microbiota were observed. Specifically, the relative abundance of Proteobacteria decreased, while that of Verrucomicrobiota increased in the high-concentration exposure group. In addition, nutrient synthesis and metabolism in the gut were affected. The results of this study contribute to a better understanding of the ecological risk of different concentrations of NAs to marine organisms. CAPSULE ABSTRACT: Changes in the gut microbial community of marine medaka (Oryzias melastigma) caused by naphthenic acids in the marine environment were investigated through the assessment of gut inflammatory factors and comprehensive analysis using 16S rDNA high-throughput sequencing. The results indicated the induction of intestinal inflammation and changes in the structural composition of the intestinal flora.

Activation of Gasdermin D (GSDMD) results in its cleavage, oligomerization, and subsequent formation of plasma membrane pores, leading to a form of inflammatory cell death denoted as pyroptosis. The roles of GSDMD in inflammation and immune responses to infection are well documented. However, whether GSDMD also plays a role in sporadic cancer development, especially that in the gut epithelium, remains unknown. Here, we show that GSDMD is activated in colorectal tumors of both human and mouse origins. Ablation of GSDMD in a mouse model of sporadic colorectal cancer resulted in reduced tumor formation in the colon and rectum, suggesting a tumor-promoting role of the protein in the gut. Both antibiotic-mediated depletion of gut microbiota and pharmacological inhibition of NLRP3 inflammasome reduced the activation of GSDMD. Loss of GSDMD resulted in reduced infiltration of immature myeloid cells, and increased numbers of macrophages in colorectal tumors. Activation of GSDMD is also accompanied by the aggregation of the endosomal sorting complex required for transport (ESCRT) membrane repair proteins on the membrane of colorectal tumor cells, suggesting that active membrane repairment may prevent pyroptosis induced by the formation of GSDMD pore in tumor cells. Our results show that gut microbiota/NLRP3-mediated activation of GSDMD promotes the development of colorectal tumors, and supports the use of NLRP3 inhibitors to treat colon cancer.

In the harsh gastrointestinal tract, helical bacteria with hierarchical chiral architectures possess strong abilities. Taking inspirations from nature, we developed a multichiral mesoporous silica nanoscrew (L/D-MCNS) as an efficient oral drug delivery platform by modifying the structural chiral silica nanoscrew (CNS) with L/D-alanine (L/D-Ala) enantiomers via the sequential application of a chiral template and postmodification strategies. We demonstrated that L-MCNS showed differential biological behaviors and superior advantages in oral adsorption compared to those of CNS, D-MCNS, and DL-MCNS. During the delivery, helical L/D-MCNS presenting distinctive topological structures, including small section area, large rough external surface, and a screw-like body, displayed multiple superiorities in mucus diffusion and mucosal adhesion. Meanwhile, the grafted chiral enantiomers enabled positive or negative chiral recognition with the biosystems. Once racemic flurbiprofen (FP) was encapsulated into the nanopores of L/D-MCNS (FP@L/D-MCNS), L/D-MCNS providing highly cross-linked and mesoscopic chiral nanochannels was beneficial for controlling the drug loading/release kinetics with chiral microenvironment sensitivity. Particularly, we noticed enantioselective absorption of FP in vivo, which could be attributed to the differential biological behaviors of L/D-MCNS. By simple design and regulation of the multilevel chirality of nanocarriers, L/D-MCNS can be employed for efficient oral drug delivery from the perspectives of material science, pharmacy, and bionics.

Cadmium (Cd) is a widely distributed environmental pollutant, primarily causing nephrotoxicity through renal proximal tubular cell impairment. Pyroptosis is an inflammation-related nucleotide-binding oligomerization segment-like receptor family 3 (NLRP3)-dependent pathway for programmed cell death. We previously reported that inappropriate inflammation caused by Cd is a major contributor to kidney injury. Therefore, research on Cd-induced inflammatory response and pyroptosis may clarify the mechanisms underlying Cd-induced nephrotoxicity. In this study, we observed that Cd-induced nephrotoxicity is associated with NLRP3 inflammasome activation, leading to an increase in proinflammatory cytokine expression and secretion, as well as pyroptosis-related gene upregulation, both in primary rat proximal tubular (rPT) cells and kidney tissue from Cd-treated rats. In vitro, these effects were significantly abrogated through siRNA-based Nlrp3 silencing; thus, Cd may trigger pyroptosis through an NLRP3 inflammasome-dependent pathway. Moreover, Cd exposure considerably elevated reactive oxygen species (ROS) content. N-acetyl-l-cysteine, an ROS scavenger, mitigated Cd-induced NLRP3 inflammasome activation and subsequent pyroptosis. Mechanistically, Cd hindered the expression and deacetylase activity of SIRT1, eventually leading to a decline in SIRT1-p65 interactions, followed by an elevation in acetylated p65 levels. The administration of resveratrol (a SIRT1 agonist) or overexpression of Sirt1 counteracted Cd-induced RELA/p65/NLRP3 pathway activation considerably, leading to pyroptosis. This is the first study to reveal significant contributions of SIRT1-triggered p65 deacetylation to pyroptosis and its protective effects against Cd-induced chronic kidney injury. Our results may aid in developing potential therapeutic strategies for preventing Cd-induced pyroptosis through SIRT1-mediated p65 deacetylation.

Chronic kidney disease (CKD) has emerged as a significant public health concern. In this article, we investigated the mechanism of oat dietary fiber in regulating CKD. Our findings indicated that the gut microbiota of CKD patients promoted gut microbiota dysbiosis and kidney injury in CKD mice. Intervention with oat-resistant starch prepared by ultrasonic combined enzymatic hydrolysis (ORSU) and oat β-glucan with a molecular weight of 5 × 104 Da (OBGM) elevated the levels of short-chain fatty acids (SCFAs) and regulated gut dysbiosis in the gut-humanized CKD mice. ORSU and OBGM also reduced CKD-related uremic toxins such as creatinine, indoxyl sulfate (IS), and p-cresol sulfate (PCS) levels; reinforced the intestinal barrier function of the gut-humanized CKD mice; and mitigated renal inflammation and fibrosis via the NF-κB/TGF-β pathway. Therefore, ORSU and OBGM might delay the progression of CKD by modulating the gut microbiota to reduce uremic toxins levels. Our results explain the mechanism of oat dietary fiber aimed at mitigating CKD.

Gasdermin D (GSDMD) is emerging as an important player in autoimmune diseases, but its exact role in lupus nephritis (LN) remains controversial. Here, we identified markedly elevated GSDMD in human and mouse LN kidneys, predominantly in CD11b+ myeloid cells. Global or myeloid-conditional deletion of GSDMD was shown to exacerbate systemic autoimmunity and renal injury in lupus mice with both chronic graft-versus-host (cGVH) disease and nephrotoxic serum (NTS) nephritis. Interestingly, RNA sequencing and flow cytometry revealed that myeloid GSDMD deficiency enhanced granulopoiesis at the hematopoietic sites in LN mice, exhibiting remarkable enrichment of neutrophil-related genes, significant increases in total and immature neutrophils as well as granulocyte/macrophage progenitors (GMPs). GSDMD-deficient GMPs and all-trans-retinoic acid (ATRA)-stimulated human promyelocytes NB4 were further demonstrated to possess enhanced clonogenic and differentiation abilities compared with controls. Mechanistically, GSDMD knockdown promoted self-renewal and granulocyte differentiation by restricting calcium influx, contributing to granulopoiesis. Functionally, GSDMD deficiency led to increased pathogenic neutrophil extracellular traps (NETs) in lupus peripheral blood and bone marrow-derived neutrophils. Taken together, our data establish that GSDMD deletion accelerates LN development by promoting granulopoiesis in a calcium influx-regulated manner, unraveling its unrecognized critical role in LN pathogenesis.

The intestinal mucosal barrier serves as a vital guardian for gut health, maintaining a delicate equilibrium between gut microbiota and host immune homeostasis. Recent studies have found the intricate roles of Gasdermin D (GSDMD), a key executioner of pyroptosis downstream of the inflammasome, within the intestine, including controlling colitis in intestinal macrophage and the regulatory function in goblet cell mucus secretion. Thus, the exact role and nature of GSDMD's regulatory function in maintaining intestinal immune homeostasis and defending against pathogens remain elucidation. Here, we uncover that GSDMD plays a key role in defending against intestinal Citrobacter rodentium infection, with high expression in intestinal epithelial and lamina propria myeloid cells. Our results show that GSDMD specifically acts in intestinal epithelial cells to fight the infection, independently of its effects on antimicrobial peptides or mucin secretion. Instead, the resistance is mediated through GSDMD's N-terminal fragments, highlighting its importance in intestinal immunity. However, the specific underlying mechanism of GSDMD N-terminal activity in protection against intestinal bacterial infections still needs further study to clarify in the future.

Pyroptosis executor GsdmD (gasdermin D) promotes atherosclerosis in mice and humans. Disulfiram was recently shown to potently inhibit GsdmD, but the in vivo efficacy and mechanism of disulfiram's antiatherosclerotic activity is yet to be explored.

We used human/mouse macrophages, endothelial cells, and smooth muscle cells and a hyperlipidemic mouse model of atherosclerosis to determine disulfiram antiatherosclerotic efficacy and mechanism. The effects of disulfiram on several atheroprotective pathways such as autophagy, efferocytosis, phagocytosis, and gut microbiota were determined. Atomic force microscopy was used to determine the effects of disulfiram on the biophysical properties of the plasma membrane of macrophages. Disulfiram-fed hyperlipidemic apolipoprotein E-/- mice showed significantly reduced interleukin-1β release upon in vivo Nlrp3 (NLR family pyrin domain containing 3) inflammasome activation. Disulfiram-fed mice showed smaller atherosclerotic lesions (~27% and 29% reduction in males and females, respectively) and necrotic core areas (~50% and 46% reduction in males and females, respectively). Disulfiram induced autophagy in macrophages, smooth muscle cells, endothelial cells, hepatocytes/liver, and atherosclerotic plaques. Disulfiram modulated other atheroprotective pathways (eg, efferocytosis, phagocytosis) and gut microbiota. Disulfiram-treated macrophages showed enhanced phagocytosis/efferocytosis, with the mechanism being a marked increase in cell-surface expression of efferocytic receptor MerTK. Atomic force microscopy analysis revealed altered biophysical properties of disulfiram-treated macrophages, showing increased order-state of plasma membrane and increased adhesion strength. Furthermore, 16sRNA sequencing of disulfiram-fed hyperlipidemic mice showed highly significant enrichment in atheroprotective gut microbiota Akkermansia and a reduction in atherogenic Romboutsia species.

Taken together, our data show that disulfiram can simultaneously modulate several atheroprotective pathways in a GsdmD-dependent as well as GsdmD-independent manner.

The gasdermin (GSDM) family has garnered significant attention for its pivotal role in immunity and disease as a key player in pyroptosis. This recently characterized class of pore-forming effector proteins is pivotal in orchestrating processes such as membrane permeabilization, pyroptosis, and the follow-up inflammatory response, which are crucial self-defense mechanisms against irritants and infections. GSDMs have been implicated in a range of diseases including, but not limited to, sepsis, viral infections, and cancer, either through involvement in pyroptosis or independently of this process. The regulation of GSDM-mediated pyroptosis is gaining recognition as a promising therapeutic strategy for the treatment of various diseases. Current strategies for inhibiting GSDMD primarily involve binding to GSDMD, blocking GSDMD cleavage or inhibiting GSDMD-N-terminal (NT) oligomerization, albeit with some off-target effects. In this review, we delve into the cutting-edge understanding of the interplay between GSDMs and pyroptosis, elucidate the activation mechanisms of GSDMs, explore their associations with a range of diseases, and discuss recent advancements and potential strategies for developing GSDMD inhibitors.

Exploring the preparation of multifunctional hydrogels from a bionic perspective is an appealing strategy. Here, a multifunctional hydrogel dressing inspired by the characteristics of porous extracellular matrix produced during Acomys wound healing is prepared. These dressings are printed by digital light processing printing of hydrogels composed of gelatin methacrylate, hyaluronic acid methacrylate, and pretreated platelet-rich plasma (PRP) to shape out triply periodic minimal surface structures, which are freeze-dried for long-term storage. These dressings mimic the porous extracellular matrix of Acomys, while the freeze-drying technique effectively extends the storage duration of PRP viability. Through in vivo and in vitro experiments, the biomimetic dressings developed in this study modulate cell behavior and facilitate wound healing. Consequently, this research offers a novel approach for the advancement of regenerative wound dressings.

Tangshen formula (TSF) has an ameliorative effect on hepatic lipid metabolism in non-alcoholic fatty liver disease (NAFLD), but the role played by the gut microbiota in this process is unknown.

We conducted three batches of experiments to explore the role played by the gut microbiota: TSF administration, antibiotic treatment, and fecal microbial transplantation. NAFLD mice were induced with a high-fat diet to investigate the ameliorative effects of TSF on NAFLD features and intestinal barrier function. 16S rRNA sequencing and serum untargeted metabolomics were performed to further investigate the modulatory effects of TSF on the gut microbiota and metabolic dysregulation in the body.

TSF ameliorated insulin resistance, hypercholesterolemia, lipid metabolism disorders, inflammation, and impairment of intestinal barrier function. 16S rRNA sequencing analysis revealed that TSF regulated the composition of the gut microbiota and increased the abundance of beneficial bacteria. Antibiotic treatment and fecal microbiota transplantation confirmed the importance of the gut microbiota in the treatment of NAFLD with TSF. Subsequently, untargeted metabolomics identified 172 differential metabolites due to the treatment of TSF. Functional predictions suggest that metabolisms of choline, glycerophospholipid, linoleic acid, alpha-linolenic acid, and arachidonic acid are the key metabolic pathways by which TSF ameliorates NAFLD and this may be influenced by the gut microbiota.

TSF treats the NAFLD phenotype by remodeling the gut microbiota and improving metabolic profile, suggesting that TSF is a functional gut microbial and metabolic modulator for the treatment of NAFLD.

Aging can cause degenerative changes in multiple tissues and organs. Gastrointestinal diseases and dysfunctions are common in the elderly population. In this study, we investigated the effects of Astragalus membranaceus polysaccharide (APS) and Astragalus membranaceus ethanol extract (AEE) on age-related intestinal dysfunction and gut microbiota dysbiosis in naturally aging mice. The energy expenditure and physical activity of 23-month-old C57BL6/J mice were recorded using a metabolic cage system. Pathological changes in the intestine were evaluated using Alcian blue staining. The protein levels of leucine-rich repeats containing G protein-coupled receptor 5 (Lgr5) and Stat3 in the small intestine were determined using immunohistochemistry. The intestinal cell migration distance was assessed using bromodeoxyuridine (BrdU) immunofluorescence staining. The gene transcription levels of intestinal stem cell (ISC) markers and ISC-related signaling pathways were detected using quantitative real-time PCR (qRT-PCR). Microbiota analysis based on 16S rDNA was performed to evaluate the composition of the gut microbiota. APS and AEE improved a series of aging phenotypes in female but not in male aging mice. APS and AEE ameliorate intestinal dysfunction and histopathological changes in aging mice. APS had a more significant anti-aging effect than AEE, particularly on intestinal dysfunction. APS promotes ISC regeneration by activating the IL-22 signaling pathway. Cohousing (CH) experiments further confirmed that APS induced the IL-22 signaling pathway by increasing the abundance of Lactobacillus, thereby promoting the regeneration of ISCs. Our results show that APS may serve as a promising agent for improving age-related intestinal dysfunction.

Regulated cell death (RCD) controls the removal of dispensable, infected or malignant cells, and is thus essential for development, homeostasis and immunity of multicellular organisms. Over the last years different forms of RCD have been described (among them apoptosis, necroptosis, pyroptosis and ferroptosis), and the cellular signaling pathways that control their induction and execution have been characterized at the molecular level. It has also become apparent that different forms of RCD differ in their capacity to elicit inflammation or an immune response, and that RCD pathways show a remarkable plasticity. Biochemical and genetic studies revealed that inhibition of a given pathway often results in the activation of back-up cell death mechanisms, highlighting close interconnectivity based on shared signaling components and the assembly of multivalent signaling platforms that can initiate different forms of RCD. Due to this interconnectivity and the pleiotropic effects of 'classical' cell death inducers, it is challenging to study RCD pathways in isolation. This has led to the development of tools based on synthetic biology that allow the targeted induction of RCD using chemogenetic or optogenetic methods. Here we discuss recent advances in the development of such toolset, highlighting their advantages and limitations, and their application for the study of RCD in cells and animals.

Periodontitis (PD) is the primary cause of tooth loss in adults. Porphyromonas gingivalis (P.g), a keystone pathogen, has been identified as a crucial contributor to this process. Pyroptosis activation in PD is acknowledged, with accumulating evidence underscoring the crucial role of Caspase-11 (described as Caspase-4/5 in humans)-mediated noncanonical pyroptosis. However, the mechanism behind its impact on PD remains unclear. In this study, we delved into the interplay between the Caspase-11-mediated noncanonical pyroptosis, subgingival microbiota alteration, and macrophage polarization. Clinical samples from PD patients revealed heightened expression of Caspase-4, gasdermin-D, and their active fragments, pointing to the activation of the noncanonical pyroptosis. Single-cell sequencing analysis linked Caspase-4 with gingival macrophages, emphasizing their involvement in PD. In vitro cell experiments confirmed that P.g-induced pyroptosis was activated in macrophages, with Casp11 deficiency attenuating these effects. In an experimental PD mouse model, Casp11 deficiency led to an alteration in subgingival microbiota composition and reduced alveolar bone resorption. Casp11-/- mice cohousing with wild-type mice confirmed the alteration of the subgingival microbiota and aggravated the alveolar bone resorption. Notably, Casp11 deficiency led to decreased M1-polarized macrophages, corresponding with reduced alveolar bone resorption, uncovering a connection between subgingival microbiota alteration, macrophage M1 polarization, and alveolar bone resorption. Taken together, we showed that Caspase-11 fulfilled a crucial role in the noncanonical pyroptosis in PD, potentially influencing the subgingival microbiota and linking to M1 polarization, which was associated with alveolar bone resorption. These findings underscored the pivotal role of the Caspase-11-mediated noncanonical pyroptosis in PD pathogenesis and may provide critical insights into potential therapeutic avenues for mitigating PD.