Paeoniflorin inhibited GSDMD to alleviate ANIT-induced cholestasis via pyroptosis signaling pathway.

BACKGROUND: Cholestasis (CT) is a group of disorders caused by impaired production, secretion or excretion of bile. This may result in the deposition of bile components in the blood and liver, which in turn causes damage to liver cells and other tissues. If untreated, CT can progress to severe complications, including cirrhosis, liver failure, and potentially life-threatening conditions. OBJECTIVE: This research was intended to elucidate the function and mechanism of Paeoniflorin (PF) in ameliorating ANIT-induced pyroptosis in CT. METHODS: CT models were established in SD rats and HepG2 cells through ANIT treatment. Histological examination was conducted using haematoxylin and eosin (HE) staining to assess the histopathological alterations in the liver. Network pharmacology was employed to identify potential PF targets in CT treatment. To evaluate pyroptosis levels, various methods were used, including serum biochemical analysis, Enzyme-Linked Immunosorbent Assay (ELISA), immunofluorescence (IF), immunohistochemistry (IHC), Western blotting, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The HuProt™ 20K Chip was utilized to pinpoint potential PF-binding targets. PF's direct mechanisms in CT treatment were explored using molecular docking (MD), molecular dynamics simulations (MDS), Cellular Thermal Shift Assay (CETSA), and Surface Plasmon Resonance (SPR). RESULTS: PF administration was found to alleviate ANIT-induced liver pathology, enhance liver function markers, and improve cell viability. Network pharmacology and pyroptosis inhibitor studies suggested that PF might mitigate CT via the NLRP3-dependent pyroptosis pathway. This hypothesis was further supported by Western blotting, IF, and IHC analyses, which indicated PF's potential to inhibit NLRP3-dependent pyroptosis in CT. GSDMD was identified as a target through HuProt™ 20K Chip screening. The binding affinity of PF to GSDMD was validated through MD, MDS, CETSA, and SPR techniques. Additionally, the regulatory impact of GSDMD on downstream inflammatory pathways was confirmed by ELISA and IHC. CONCLUSION: PF exhibited a hepatoprotective effect in ANIT-induced CT, primarily by targeting GSDMD, thereby suppressing ANIT-induced pyroptosis and the subsequent release of inflammatory mediators.

Small-molecule GSDMD agonism in tumors stimulates antitumor immunity without toxicity.

Gasdermin-mediated inflammatory cell death (pyroptosis) can activate protective immunity in immunologically cold tumors. Here, we performed a high-throughput screen for compounds that could activate gasdermin D (GSDMD), which is expressed widely in tumors. We identified 6,7-dichloro-2-methylsulfonyl-3-N-tert-butylaminoquinoxaline (DMB) as a direct and selective GSDMD agonist that activates GSDMD pore formation and pyroptosis without cleaving GSDMD. In mouse tumor models, pulsed and low-level pyroptosis induced by DMB suppresses tumor growth without harming GSDMD-expressing immune cells. Protection is immune-mediated and abrogated in mice lacking lymphocytes. Vaccination with DMB-treated cancer cells protects mice from secondary tumor challenge, indicating that immunogenic cell death is induced. DMB treatment synergizes with anti-PD-1. DMB treatment does not alter circulating proinflammatory cytokine or leukocyte numbers or cause weight loss. Thus, our studies reveal a strategy that relies on a low level of tumor cell pyroptosis to induce antitumor immunity and raise the possibility of exploiting pyroptosis without causing overt toxicity.

Role of gasdermin D in inflammatory diseases: from mechanism to therapeutics.

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.

RMRP accelerates ligamentum flavum hypertrophy by regulating GSDMD-mediated pyroptosis through Gli1 SUMOylation.

Hypertrophy of ligamentum flavum (LF) is a significant contributing factor to lumbar spinal canal stenosis (LSCS). lncRNA plays a vital role in organ fibrosis, but its role in LF fibrosis remains unclear. Our previous findings have demonstrated that Hedgehog-Gli1 signaling is a critical driver leading to LF hypertrophy. Through the RIP experiment, our group found lnc-RMRP was physically associated with Gli1 and exhibited enrichment in Gli1-activated LF cells. Histological studies revealed elevated expression of RMRP in hypertrophic LF. In vitro experiments further confirmed that RMRP promoted Gli1 SUMO modification and nucleus transfer. Mechanistically, RMRP induced GSDMD-mediated pyroptosis, proinflammatory activation, and collagen expression through the Hedgehog pathway. Notably, the mechanical stress-induced hypertrophy of LF in rabbit exhibited analogous pathological changes of LF fibrosis occurred in human and showed enhanced levels of collagen and α-SMA. Knockdown of RMRP resulted in the decreased expression of fibrosis and pyroptosis-related proteins, ultimately ameliorating fibrosis. The above data concluded that RMRP exerts a crucial role in regulating GSDMD-mediated pyroptosis of LF cells via Gli1 SUMOylation, thus indicating that targeting RMRP could serve as a potential and effective therapeutic strategy for LF hypertrophy and fibrosis.

The impact of AIM2 inflammasome-induced pyroptosis on acute gouty arthritis and asymptomatic hyperuricemia patients.

Objective: This study aimed to evaluate the role of absent in melanoma 2 (AIM2) inflammasome-mediated pyroptosis in the pathogenesis of acute gouty arthritis (AGA) and asymptomatic hyperuricemia(AHU). Methods: A cohort of 30 AGA patients, 30 AHU individuals, and 30 healthy controls (HC) was assembled. Demographic and biochemical data, along with blood samples, were collected. Serum double-stranded DNA (dsDNA) levels were quantified using a fluorescent assay. Transcriptomic and proteomic analysis of AIM2, Caspase-1, GSDMD, IL-1ß, and IL-18 in peripheral blood mononuclear cells was performed using qRT-PCR and Western blot. Enzyme-linked immunosorbent assay (ELISA) was employed to measure serum IL-1ß and IL-18. Spearman correlation analysis was utilized to assess relationships between variables. Results: Both AGA and AHU groups demonstrated elevated metabolic indicators and serum levels of dsDNA, IL-1ß, and IL-18 compared to the HC group. AGA patients exhibited higher inflammatory markers than the AHU group. In the AGA group, there was a significant increase in the mRNA and protein levels of AIM2, Caspase-1, GSDMD, IL-1ß, and IL-18 (P<0.05 to P<0.001). The AHU group showed higher AIM2, Caspase-1, GSDMD, and IL-18 mRNA levels than the HC group (P<0.001 to P<0.01), with a non-significant increase in AIM2, GSDMD, and IL-1ß proteins (P>0.05). In contrast, Caspase-1 and IL-18 proteins were significantly higher in the AHU group (P<0.05). Notable correlations were observed between AIM2 protein expression and levels of Caspase-1 and GSDMD in both AGA and AHU groups. In the AGA group, AIM2 protein correlated with IL-1ß, but not in the AHU group. The AIM2 protein in the AHU group was positively associated with IL-18, with no such correlation in the AGA group. Conclusion: AIM2 inflammasome may play a role in the inflammatory processes of AGA and AHU and that its activation may be related to the pyroptosis pathway.

Bile acids attenuate hepatic inflammation during ischemia/reperfusion injury.

Background & Aims: Persistent cholestasis has been associated with poor prognosis after orthotopic liver transplantation. In this study, we aimed to investigate how the accumulation of tauro-beta-muricholic acid (TßMCA), resulting from the reprogramming of bile acid (BA) metabolism during liver ischemia/reperfusion (IR) stress, attenuates liver inflammation. Methods: Ingenuity Pathway Analysis was performed using transcriptome data from a murine hepatic IR model. Three different models of hepatic IR (liver warm IR, bile duct separation-IR, common bile duct ligation-IR) were employed. We generated adeno-associated virus-transfected mice and CD11b-DTR mice to assess the role of BAs in regulating the myeloid S1PR2-GSDMD axis. Hepatic BA levels were analyzed using targeted metabolomics. Finally, the correlation between the reprogramming of BA metabolism and hepatic S1PR2 levels was validated through RNA-seq of human liver transplant biopsies. Results: We found that BA metabolism underwent reprogramming in murine hepatocytes under IR stress, leading to increased synthesis of TßMCA, catalyzed by the enzyme CYP2C70. The levels of hepatic TßMCA were negatively correlated with the severity of hepatic inflammation, as indicated by the serum IL-1ß levels. Inhibition of hepatic CYP2C70 resulted in reduced TßMCA production, which subsequently increased serum IL-1ß levels and exacerbated IR injury. Moreover, our findings suggested that TßMCA could inhibit canonical inflammasome activation in macrophages and attenuate inflammatory responses in a myeloid-specific S1PR2-GSDMD-dependent manner. Additionally, Gly-ßMCA, a derivative of TßMCA, could effectively attenuate inflammatory injury in vivo and inhibit human macrophage pyroptosis in vitro. Conclusions: IR stress orchestrates hepatic BA metabolism to generate TßMCA, which attenuates hepatic inflammatory injury by inhibiting the myeloid S1PR2-GSDMD axis. Bile acids have immunomodulatory functions in liver reperfusion injury that may guide therapeutic strategies. Impact and implications: Our research reveals that liver ischemia-reperfusion stress triggers reprogramming of bile acid metabolism. This functions as an adaptive mechanism to mitigate inflammatory injury by regulating the S1PR2-GSDMD axis, thereby controlling the release of IL-1ß from macrophages. Our results highlight the crucial role of bile acids in regulating hepatocyte-immune cell crosstalk, which demonstrates an immunomodulatory function in liver reperfusion injury that may guide therapeutic strategies targeting bile acids and their receptors.

Icaritin Exerts Anti-Cancer Effects through Modulating Pyroptosis and Immune Activities in Hepatocellular Carcinoma.

Icaritin (ICT), a natural compound extracted from the dried leaves of the genus Epimedium, possesses antitumor and immunomodulatory properties. However, the mechanisms through which ICT modulates pyroptosis and immune response in hepatocellular carcinoma (HCC) remain unclear. This study demonstrated that ICT exhibits pyroptosis-inducing and anti-hepatocarcinoma effects. Specifically, the caspase1-GSDMD and caspase3-GSDME pathways were found to be involved in ICT-triggered pyroptosis. Furthermore, ICT promoted pyroptosis in co-cultivation of HepG2 cells and macrophages, regulating the release of inflammatory cytokines and the transformation of macrophages into a proinflammatory phenotype. In the Hepa1-6+Luc liver cancer model, ICT treatment significantly increased the expression of cleaved-caspase1, cleaved-caspase3, and granzyme B, modulated cytokine secretion, and stimulated CD8+ T cell infiltration, resulting in a reduction in tumor growth. In conclusion, the findings in this research suggested that ICT may modulate cell pyroptosis in HCC and subsequently regulate the immune microenvironment of the tumor. These observations may expand the understanding of the pharmacological mechanism of ICT, as well as the therapy of liver cancer.

A Combination of Astragaloside IV and Hydroxysafflor Yellow A Attenuates Cerebral Ischemia-Reperfusion Injury via NF-κB/NLRP3/Caspase-1/GSDMD Pathway.

Cerebral ischemia-reperfusion injury (IRI), occurring after blood supply restoration, contributes significantly to stroke-related deaths. This study explored the combined impact and mechanisms of astragaloside IV (AS-IV), hydroxysafflor yellow A (HSYA), and their combination in mitigating IRI. Male Sprague-Dawley (SD) rats were randomized to the Sham, MCAO, MCAO+AS-IV, MCAO+HSYA, and MCAO+AS-IV+HSYA groups. Neurological deficits and cerebral infarction were examined after restoring the blood supply to the brain. Pathomorphological changes in the cerebral cortex were observed via HE staining. IL-1ß and IL-18 were quantified using ELISA. The expression of NF-κB and GSDMD in the ischemic cerebrum was analyzed using immunohistochemistry. The expression levels of NLRP3, ASC, IL-1ß, Caspase-1, and GSDMD in the ischemic cerebrum were evaluated using Western blot. The MCAO+AS-IV, MCAO+HSYA, and MCAO+AS-IV+HSYA groups exhibited notably better neurological function and cerebral infarction compared with the MCAO group. The combined treatment demonstrated superior brain tissue injury alleviation. Reductions in NF-κB, GSDMD positive cells, and NLRP3/ASC/IL-1ß/Caspase-1/GSDMD protein expression in the ischemic brain were significantly more pronounced with the combined therapy, indicating a synergistic effect in countering cerebral IRI via the NF-κB/NLRP3/Caspase-1/GSDMD pathway inhibition of cell pyroptosis-induced injury.

Igniting hope: Harnessing NLRP3 inflammasome-GSDMD-mediated pyroptosis for cancer immunotherapy.

In the contemporary landscape of oncology, immunotherapy, represented by immune checkpoint blockade (ICB) therapy, stands out as a beacon of innovation in cancer treatment. Despite its promise, the therapy's progression is hindered by suboptimal clinical response rates. Addressing this challenge, the modulation of the NLRP3 inflammasome-GSDMD-mediated pyroptosis pathway holds promise as a means to augment the efficacy of immunotherapy. In the pathway, the NLRP3 inflammasome serves as a pivotal molecular sensor that responds to inflammatory stimuli within the organism. Its activation leads to the release of cytokines interleukin 1ß and interleukin 18 through the cleavage of GSDMD, thereby forming membrane pores and potentially resulting in pyroptosis. This cascade of processes exerts a profound impact on tumor development and progression, with its function and expression exhibiting variability across different tumor types and developmental stages. Consequently, understanding the specific roles of the NLRP3 inflammasome and GSDMD-mediated pyroptosis in diverse tumors is imperative for comprehending tumorigenesis and crafting precise therapeutic strategies. This review aims to elucidate the structure and activation mechanisms of the NLRP3 inflammasome, as well as the induction mechanisms of GSDMD-mediated pyroptosis. Additionally, we provide a comprehensive overview of the involvement of this pathway in various cancer types and its applications in tumor immunotherapy, nanotherapy, and other fields. Emphasis is placed on the feasibility of leveraging this approach to enhance ICB therapy within the field of immunotherapy. Furthermore, we discuss the potential applications of this pathway in other immunotherapy methods, such as chimeric antigen receptor T-cell (CAR-T) therapy and tumor vaccines.

Evaluation of immune and pyroptosis status in a model of sepsis-induced secondary pneumonia.

In recent years, researchers have focused on studying the mechanism of sepsis-induced immunosuppression, but there is still a lack of suitable animal models that accurately reflect the process of sepsis-induced immunosuppression. The aim of this study was to evaluate the immune status at various stages in a model of sepsis-induced secondary pneumonia and to demonstrate whether pyroptosis is one of the modes of immune cell death in sepsis. Firstly, we established a sepsis model in C57BL/6J mice using cecal ligation and puncture (CLP). The surviving mice were treated with a 40 µL suspension of P.aeruginosa (Pa) under anesthesia on day 4 post-CLP to establish a sepsis-induced secondary pneumonia model. Secondly, routine blood tests, serum ALT and PCT levels, gross lung specimens, and H&E staining of the lung and liver tissues were used to assess the successful establishment of this model. Serum levels of TNF-α and IL-6, the CD4+/CD8+ratio in blood, H&E staining of the spleen, and immunohistochemistry of CD4 and CD8 in the spleen were detected to evaluate the immune status of the model mice. Finally, the expression levels of pyroptosis-related proteins in the spleen were detected by Western blot. The expression of GSDMD was assessed using immunohistochemistry, and pyroptosis was directly observed through transmission electron microscopy. The experimental results above confirmed the successful construction of the model for sepsis-induced secondary pneumonia, demonstrating its ability to reflect sepsis-induced immunosuppression. Moreover, the expression of pyroptosis-related proteins, immunohistochemical GSDMD, and transmission electron microscopy of the spleen showed that pyroptosis was one of the modes of immune cell death in sepsis.

Caspase-11 signaling promotes damage to hippocampal CA3 to enhance cognitive dysfunction in infection.

BACKGROUND: Cognitive dysfunction caused by infection frequently emerges as a complication in sepsis survivor patients. However, a comprehensive understanding of its pathogenesis remains elusive. METHODS: In our in vivo experiments, an animal model of endotoxemia was employed, utilizing the Novel Object Recognition Test and Morris Water Maze Test to assess cognitive function. Various techniques, including immunofluorescent staining, Western blotting, blood‒brain barrier permeability assessment, Limulus Amebocyte Lysate (LAL) assay, and Proximity-ligation assay, were employed to identify brain pathological injury and neuroinflammation. To discern the role of Caspase-11 (Casp11) in hematopoietic or non-hematopoietic cells in endotoxemia-induced cognitive decline, bone marrow chimeras were generated through bone marrow transplantation (BMT) using wild-type (WT) and Casp11-deficient mice. In vitro studies involved treating BV2 cells with E. coli-derived outer membrane vesicles to mimic in vivo conditions. RESULTS: Our findings indicate that the deficiency of Casp11-GSDMD signaling pathways reverses infection-induced cognitive dysfunction. Moreover, cognitive dysfunction can be ameliorated by blocking the IL-1 effect. Mechanistically, the absence of Casp11 signaling significantly mitigated blood‒brain barrier leakage, microglial activation, and synaptic damage in the hippocampal CA3 region, ultimately leading to improved cognitive function. CONCLUSION: This study unveils the crucial contribution of Casp11 and GSDMD to cognitive impairments and spatial memory loss in a murine sepsis model. Targeting Casp11 signaling emerges as a promising strategy for preventing or treating cognitive dysfunction in patients with severe infections.

Inflammation unleashed: The role of pyroptosis in chronic liver diseases.

Pyroptosis, a newly identified form of programmed cell death intertwined with inflammatory responses, is facilitated by the Gasdermin family's pore-forming activity, leading to cell lysis and the release of pro-inflammatory cytokines. This process is a double-edged sword in innate immunity, offering protection against pathogens while risking excessive inflammation and tissue damage when dysregulated. Specifically, pyroptosis operates through two distinct signaling pathways, namely the Caspase-1 pathway and the Caspase-4/5/11 pathway. In the context of chronic liver diseases like fibrosis and cirrhosis, inflammation emerges as a central contributing factor to their pathogenesis. The identification of inflammation is characterized by the activation of innate immune cells and the secretion of pro-inflammatory cytokines such as IL-1α, IL-1ß, and TNF-α. This review explores the interrelationship between pyroptosis and the inflammasome, a protein complex located in liver cells that recognizes danger signals and initiates Caspase-1 activation, resulting in the secretion of IL-1ß and IL-18. The article delves into the influence of the inflammasome and pyroptosis on various liver disorders, with a specific focus on their molecular and pathophysiological mechanisms. Additionally, the potential therapeutic implications of targeting pyroptosis for liver diseases are highlighted for future consideration.

Pre-electroacupuncture Ameliorates Cerebral Ischemia-reperfusion Injury by Inhibiting Microglial RhoA/pyrin/GSDMD Signaling Pathway.

Cerebral ischemia reperfusion injury is a severe neurological impairment that occurs after blood flow reconstruction in stroke, and microglia cell pyroptosis is one of its important mechanisms. Electroacupuncture has been shown to be effective in mitigating and alleviating cerebral ischemia reperfusion injury by inhibiting neuroinflammation, reducing cellular pyroptosis, and improving neurological function. In this experiment, we divided the rats into three groups, including the sham operation (Sham) group, the middle cerebral artery occlusion/reperfusion (MCAO/R) group, and the pre-electroacupuncture (EAC) group. Pre-electroacupuncture group was stimulated with electroacupuncture of a certain intensity on the Baihui (GV 20) and Dazhui (GV 14) of the rat once a day from the 7th day to the 1st day before the MCAO/R operation. The extent of cerebral infarction was detected by TTC staining. A modified Zea-Longa five-point scale scoring system was used to determine neurologic function in MCAO rats. The number of neurons and morphological changes were accessed by Nissl staining and HE staining. The cellular damage was detected by TUNEL staining. In addition, the expression levels of RhoA, pyrin, GSDMD, Caspase1, cleaved-Caspase1, Iba-1, CD206, and ROCK2 were examined by western blotting and immunofluorescence. The results found that pre-electroacupuncture significantly attenuated neurological impairment and cerebral infarction compared to the post-MCAO/R rats. In addition, pre-electroacupuncture therapy promoted polarization of microglia to the neuroprotective (M2) phenotype. In addition, pre-electroacupuncture inhibited microglia pyroptosis by inhibiting RhoA/pyrin/GSDMD signaling pathway, thereby reducing neuronal injury and increasing neuronal survival in the MCAO/R rats. Taken together, these results demonstrated that pre-acupuncture could attenuate cerebral ischemia-reperfusion injury by inhibiting microglial pyroptosis. Therefore, pre-electroacupuncture might be a potential preventive strategy for ischemic stroke patients.

Atg16l2 augments Nlrc4 inflammasome activation by facilitating NAIPs-NLRC4 association.

As cytoplasmic protein complexes that are pivotal for innate immunity, inflammasomes act primarily through the detection of pathogen- or danger-associated molecular patterns. Nucleotide oligomerisation domain-like receptor family and caspase activation recruitment domain-containing protein 4 (NLRC4) inflammasomes identify and eliminate intracellular pathogens, a process contingent on the ligand-recognition capabilities of neuronal apoptosis inhibitory proteins (NAIPs). Upon detection of specific molecules indicative of intracellular infection, NAIPs discern distinct pathogenic components and subsequently transmit signals to NLRC4, thus initiating their activation and triggering an inflammatory response. However, the mechanisms underlying NLRC4 inflammasome remain unclear. In this study, we elucidated the critical role of ATG16L2 in activating the NLRC4 inflammasome. ATG16L2-deficient macrophages exhibited reduced NLRC4 inflammasome activation, characterised by decreased oligomerisation of apoptosis-associated speck-like protein containing a CARD and attenuated cleavage of Pro-caspase-1, Pro-IL-1ß and gasdermin D. Co-immunoprecipitation assays revealed an interaction between ATG16L2 and NAIPs. Furthermore, ATG16L2 enhanced the association between NAIPs and NLRC4 by binding to NAIPs. For ATG16L2-knockout mice infected with Salmonella typhimurium, pathogen clearance and survival rates markedly decreased. Collectively, our findings suggest that ATG16L2 is a significant modulator of the innate immune system, influencing the activity of the NLRC4 inflammasome and the host's defensive response to intracellular pathogens.

Multiple sclerosis: the NLRP3 inflammasome, gasdermin D, and therapeutics.

Multiple sclerosis (MS) stands as a chronic inflammatory disease characterized by its neurodegenerative impacts on the central nervous system. The complexity of MS and the significant challenges it poses to patients have made the exploration of effective treatments a crucial area of research. Among the various mechanisms under investigation, the role of inflammation in MS progression is of particular interest. Inflammatory responses within the body are regulated by various cellular mechanisms, one of which involves the nucleotide-binding oligomerization domain (NOD)-, leucine-rich repeat (LRR)-, and pyrin domains (PYD)-containing protein 3 (NLRP3). NLRP3 acts as a sensor within cells, playing a pivotal role in controlling the inflammatory response. Its activation is a critical step leading to the assembly of the NLRP3 inflammasome complex, a process that has profound implications for inflammatory diseases like MS. The NLRP3 inflammasome's activation is intricately linked to the subsequent activation of caspase 1 and gasdermin D (GsdmD), signaling pathways that are central to the inflammatory process. GsdmD, a prominent member of the Gasdermin protein family, is particularly noteworthy for its role in pyroptotic cell death, a form of programmed cell death that is distinct from apoptosis and is characterized by its inflammatory nature. This pathway's activation contributes significantly to the pathology of MS by exacerbating inflammatory responses within the nervous system. Given the detrimental effects of unregulated inflammation in MS, therapeutics targeting these inflammatory processes offer a promising avenue for alleviating the symptoms experienced by patients. This review delves into the intricacies of the pyroptotic pathways, highlighting how the formation of the NLRP3 inflammasome induces such pathways and the potential intervention points for therapeutic agents. By inhibiting key steps within these pathways, it is possible to mitigate the inflammatory response, thereby offering relief to those suffering from MS. Understanding these mechanisms not only sheds light on the pathophysiology of MS but also paves the way for the development of novel therapeutic strategies aimed at controlling the disease's progression through the modulation of the body's inflammatory response.

Gasdermin D Mediated Mitochondrial Metabolism Orchestrate Neurogenesis Through LDHA During Embryonic Development.

Regulatory cell death is an important way to eliminate the DNA damage that accompanies the rapid proliferation of neural stem cells during cortical development, including pyroptosis, apoptosis, and so on. Here, the study reports that the absence of GSDMD-mediated pyroptosis results in defective DNA damage sensor pathways accompanied by aberrant neurogenesis and autism-like behaviors in adult mice. Furthermore, GSDMD is involved in organizing the mitochondrial electron transport chain by regulating the AMPK/PGC-1α pathway to target Aifm3. This process promotes a switch from oxidative phosphorylation to glycolysis. The perturbation of metabolic homeostasis in neural progenitor cells increases lactate production which acts as a signaling molecule to regulate the p38MAPK pathway. And activates NF-𝜿B transcription to disrupt cortex development. This abnormal proliferation of neural progenitor cells can be rescued by inhibiting glycolysis and lactate production. Taken together, the study proposes a metabolic axis regulated by GSDMD that links pyroptosis with metabolic reprogramming. It provides a flexible perspective for the treatment of neurological disorders caused by genotoxic stress and neurodevelopmental disorders such as autism.

The Protective Effect of Melatonin on LPS-Induced Myocardial Injury via the Caspase-11/GSDMD Pathway.

BACKGROUND: Melatonin (MT) has been demonstrated to have cardioprotective effects. Nevertheless, the precise mechanism through which MT provides protection against the etiology of LPS-induced myocardial injury remains uncertain. In this investigation, our objective was to explore the impact of MT on LPS-induced myocardial injury in an in vitro setting. METHODS: H9C2 cells were categorized into four groups: a control group (H9C2 group), an MT group, an LPS group, and an MT + LPS group. The H9C2 group received treatment with sterile saline solution, the LPS group was exposed to 5 µg/mL LPS for 24 hours, the MT + LPS group underwent pretreatment with 150 µmol/L MT for 2 hours, followed by exposure to 5 µg/mL LPS for 24 hours, and the MT group received only 150 µmol/L MT for 2 hours. Cell viability and lactate dehydrogenase (LDH) release were assessed using the CCK-8 assay and LDH activity assay, respectively. The levels of reactive oxygen species (ROS) were quantified in each group of cells, and the percentage of propidium iodide (PI)-stained apoptotic cells was determined by flow cytometry. The mRNA levels of caspase11, GSDMD, and IL-18 in each group of cells were quantified. RESULTS: MT treatment significantly protected H9C2 cells from LPS-induced damage, as evidenced by decreased LDH release. LPS treatment markedly increased ROS levels in H9C2 cells, which were subsequently reduced by MT. LPS caused a substantial decrease in superoxide dismutase (SOD) activity and a significant increase in malondialdehyde (MDA) levels, while MT treatment significantly reversed these effects. Additionally, MT markedly enhanced the proportion of viable H9C2 cells compared to LPS-treated controls, as evidenced by the PI staining assay. LPS upregulated both mRNA levels and protein levels of IL-18 in H9C2 cells. However, MT treatment effectively mitigated this LPS-induced increase. Furthermore, MT significantly decreased LPS-induced protein levels of cleaved-caspase 11 and GSDMD-N in H9C2 cells. CONCLUSION: Overall, our findings suggest that MT inhibits the Caspase11-GSDMD signaling pathway via pyroptosis-related proteins (caspase-11 and GSDMD-N) and reduces the expression of inflammation-related cytokines (IL-18), thereby exerting a protective effect on H9C2 cells after LPS injury.

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.

Inducers and Inhibitors of Pyroptotic Death of Granulosa Cells in Models of Premature Ovarian Insufficiency and Polycystic Ovary Syndrome.

Granulosa cells (GCs), the largest cell population and primary source of steroid hormones in the ovary, are the important somatic ovarian components. They have critical roles in folliculogenesis by supporting oocyte, facilitating its growth, and providing a microenvironment suitable for follicular development and oocyte maturation, thus having essential functions in maintaining female fertility and in reproductive health in general. Pyroptotic death of GCs and associated inflammation have been implicated in the pathogenesis of several reproductive disorders in females including Premature Ovarian Insufficiency (POI) and Polycystic Ovary Syndrome (PCOS). Here, I reviewed factors, either intrinsic or extrinsic, that induce or inhibit pyroptosis in GCs in various models of these disorders, both in vitro and in vivo, and also covered associated molecular mechanisms. Most of these studied factors influence NLRP3 inflammasome- and GSDMD (Gasdermin D)-mediated pyroptosis in GCs, compared to other inflammasomes and gasdermins (GSDMs). I conclude that a more complete mechanistic understanding of these factors in terms of GC pyroptosis is required to be able to develop novel strategies targeting inflammatory cell death in the ovary.