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.

[Regulation of electroacupuncture on non-canonical pathway of hepatocellular pyroptosis in rats with nonalcoholic fatty liver disease].

OBJECTIVE: To observe the effect and mechanism of electroacupuncture (EA) on non-canonical pathway of hepatocellular pyroptosis in nonalcoholic fatty liver disease (NAFLD). METHODS: Sixty male SD rats were randomly divided into a normal diet group (n=15) and a high fat modeling group (n=45). The rats in the high fat modeling group were fed with customized high fat diet for 8 weeks to establish NAFLD model. Thirty successfully modeled rats were selected and randomly divided into a model group (n=10), an EA group (n=10) and a non-acupoint with shallow needling group (n=10), and 10 rats were randomly selected from the normal diet group as the control group additionally. In the EA group, EA was applied at bilateral "Fenglong" (ST 40) and "Ganshu" (BL 18), with disperse-dense wave, in frequency of 4 Hz/20 Hz and in intensity of 3 mA. In the non-acupoint with shallow needling group, shallow needling was delivered at points 5 mm from bilateral "Fenglong" (ST 40) and "Ganshu" (BL 18), the EA stimulation parameters were same as the EA group. The intervention was given once a day, 20 min a time, 5 days a week for 4 weeks in the two groups. After intervention, the liver morphology was observed by oil red "O" staining, the serum levels of lipopolysaccharide (LPS), interleukin (IL)-1ß, IL-18 and tumor necrosis factor-α (TNF-α) were detected by ELISA, the protein expression of gasdermin D (GSDMD), GSDMD-N, cysteine aspartic acid specific protease-11 (Caspase-11), IL-1ß, IL-18 and TNF-α in liver tissue were detected by Western blot, the mRNA expression of GSDMD, Caspase-11, IL-1ß, IL-18 and TNF-α in liver tissue was detected by real-time PCR in rats of each group. RESULTS: In the model group, vacuoles in different size were found in the hepatocellular cytoplasm, and the fat droplets were in schistose accumulation. Compared with the model group, the hepatocellular fat droplets and the degree of hepatic steatosis were reduced in the EA group and the non-acupoint with shallow needling group. Compared with the control group, the serum levels of LPS, IL-1ß, IL-18 and TNF-α were increased (P<0.01), the protein and mRNA expression of GSDMD, Caspase-11, IL-1ß, IL-18, TNF-α as well as the protein expression of GSDMD-N in the liver tissue were increased (P<0.01) in the model group. Compared with the model group, the serum levels of LPS, IL-1ß, IL-18 and TNF-α were decreased (P<0.01), the protein and mRNA expression of GSDMD, IL-1ß, IL-18 and TNF-α in the liver tissue were decreased (P<0.01), the protein expression of GSDMD-N and the mRNA expression of Caspase-11 in the liver tissue were decreased (P<0.01) in the EA group and the non-acupoint with shallow needling group. Compared with the model group, the protein expression of Caspase-11 in the liver tissue was decreased (P<0.01) in the EA group. Compared with the non-acupoint with shallow needling group, the serum levels of LPS, IL-1ß, IL-18 and TNF-α were decreased (P<0.01), the protein and mRNA expression of GSDMD, Caspase-11, IL-1ß and IL-18 in the liver tissue were decreased (P<0.01), the protein expression of GSDMD-N and the mRNA expression of TNF-α in the liver tissue were decreased (P<0.01) in the EA group. CONCLUSION: EA can inhibit hepatocellular pyroptosis in NAFLD rats, and its mechanism may be related to reducing the serum level of LPS, and down-regulating the expression of the non-canonical pathway related factors i.e. GSDMD, GSDMD-N, Caspase-11, IL-1ß, IL-18 and TNF-α.

Exploring the role of pyroptosis in the pathogenicity of heart disease.

Cell death is an essential cellular mechanism that ensures quality control and whole-body homeostasis. Various modes of cell death have been studied and detailed. Unbalanced cell death can lead to uncontrolled cell proliferation (i.e., tumors) or excessive loss of cells (i.e., ischemia injury tissue loss). Thus, it is imperative for modes of cell death to be balanced and controlled. Here, we will focus on a recent mode of cell death called pyroptosis. While extensive studies have shown the role of this route of cell death in macrophages and monocytes, evidence for pyroptosis have expanded to encompass other pathologies, including cancer and cardiac diseases. Herein, we provide a brief review on pyroptosis and discuss current gaps in knowledge and scientific advances in cardiac pyroptosis in recent years. Lastly, we provide conclusions and prospective on the relevance to various cardiac diseases.

Bhlhe40 deficiency attenuates LPS-induced acute lung injury through preventing macrophage pyroptosis.

BACKGROUND: Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS) as common life-threatening lung diseases with high mortality rates are mostly associated with acute and severe inflammation in lungs. Recently, increasing evidence supports activated inflammation and gasdermin D (GSDMD)-mediated pyroptosis in macrophage are closely associated with ALI. Basic helix-loop-helix family member e40 (Bhlhe40) is a transcription factor that is comprehensively involved in inflammation. However, there is little experimental evidence connecting Bhlhe40 and GSDMD-driven pyroptosis. The study sought to verify the hypothesis that Bhlhe40 is required for GSDMD-mediated pyroptosis in lipopolysaccharide (LPS)-induced inflammatory injury. METHOD: We performed studies using Bhlhe40-knockout (Bhlhe40 -/-) mice, small interfering RNA (siRNA) targeting Bhlhe40 and pyroptosis inhibitor disulfiram to investigate the potential roles of Bhlhe40 on LPS-induced ALI and the underlying mechanisms. RESULTS: Bhlhe40 was highly expressed in total lung tissues and macrophages of LPS-induced mice. Bhlhe40-/- mice showed alleviative lung pathological injury and inflammatory response upon LPS stimulation. Meanwhile, we found that Bhlhe40 deficiency significantly suppressed GSDMD-mediated pyroptosis in macrophage in vivo and in vitro. By further mechanistic analysis, we demonstrated that Bhlhe40 deficiency inhibited GSDMD-mediated pyroptosis and subsequent ALI by repressing canonical (caspase-1-mediated) and non-canonical (caspase-11-mediated) signaling pathways in vivo and in vitro. CONCLUSION: These results indicate Bhlhe40 is required for LPS-induced ALI. Bhlhe40 deficiency can inhibit GSDMD-mediated pyroptosis and therefore alleviate ALI. Targeting Bhlhe40 may be a potential therapeutic strategy for LPS-induced ALI.

Phagocytic cell death leads to enhanced release of pro-inflammatory S100A12 in familial Mediterranean fever.

BACKGROUND: Familial Mediterranean fever (FMF) is a prototypical autoinflammatory syndrome associated with phagocytic cell activation. Pyrin mutations are the genetic basis of this disease, and its expression has been shown in monocytes, granulocytes, dendritic cells, and synovial fibroblasts. Pyrin functions as a cytosolic pattern recognition receptor and forms a distinct pyrin inflammasome. The phagocyte-specific protein S100A12 is predominantly expressed in granulocytes and belongs to the group of damage associated molecular patterns (DAMP). S100A12 can be detected at massively elevated levels in the serum of FMF patients, even in clinically inactive disease. Whether this is crucial for FMF pathogenesis is as yet unknown, and we therefore investigated the mechanisms of S100A12 release from granulocytes of FMF patients presenting clinically inactive. RESULTS: We demonstrate that FMF neutrophils from patients in clinical inactive disease possess an intrinsic activity leading to cell death even in exogenously unstimulated neutrophils. Cell death resembles NETosis and is dependent on ROS and pore forming protein gasdermin D (GSDMD), as inhibitors for both are capable of completely block cell death and S100A12 release. When pyrin-activator TcdA (Clostridium difficile toxin A) is used to stimulate, neutrophilic cell death and S100A12 release are significantly enhanced in neutrophils from FMF patients compared to neutrophils from HC. CONCLUSIONS: We are able to demonstrate that activation threshold of neutrophils from inactive FMF patients is decreased, most likely by pre-activated pyrin. FMF neutrophils present with intrinsically higher ROS production, when cultured ex vivo. This higher baseline ROS activity leads to increased GSDMD cleavage and subsequent release of, e.g., S100A12, and to increased cell death with features of NETosis and pyroptosis. We show for the first time that cell death pathways in neutrophils of inactive FMF patients are easily triggered and lead to ROS- and GSDMD-dependent activation mechanisms and possibly pathology. This could be therapeutically addressed by blocking ROS or GSDMD cleavage to decrease inflammatory outbreaks when becoming highly active.

GSDMD-mediated pyroptosis promotes cardiac remodeling in pressure overload.

BACKGROUND: Gasdermin D (GSDMD) forms membrane pores to execute pyroptosis. But the mechanism of how cardiomyocyte pyroptosis induces cardiac remodeling in pressure overload remains unclear. We investigated the role of GSDMD-mediated pyroptosis in the pathogenesis of cardiac remodeling in pressure overload. METHODS: Wild-type (WT) and cardiomyocyte-specific GSDMD-deficient (GSDMD-CKO) mice were subjected to transverse aortic constriction (TAC) to induce pressure overload. Four weeks after surgery, left ventricular structure and function were evaluated by echocardiographic, invasive hemodynamic and histological analysis. Pertinent signaling pathways related to pyroptosis, hypertrophy and fibrosis were investigated by histochemistry, RT-PCR and western blotting. The serum levels of GSDMD and IL-18 collected from healthy volunteers or hypertensive patients were measured by ELISA. RESULTS: We found TAC induced cardiomyocyte pyroptosis and release of pro-inflammatory cytokines IL-18. The serum GSDMD level was significantly higher in hypertensive patients than in healthy volunteers, and induced more dramatic release of mature IL-18. GSDMD deletion remarkably mitigated TAC-induced cardiomyocyte pyroptosis. Furthermore, GSDMD deficiency in cardiomyocytes significantly reduced myocardial hypertrophy and fibrosis. The deterioration of cardiac remodeling by GSDMD-mediated pyroptosis was associated with activating JNK and p38 signaling pathways, but not ERK or Akt signaling pathway. CONCLUSION: In conclusion, our results demonstrate that GSDMD serves as a key executioner of pyroptosis in cardiac remodeling induced by pressure overload. GSDMD-mediated pyroptosis activates JNK and p38 signaling pathways, and this may provide a new therapeutic target for cardiac remodeling induced by pressure overload.

Crosstalk Between Cholesterol, ABC Transporters, and PIP2 in Inflammation and Atherosclerosis.

The lowering of plasma low-density lipoprotein cholesterol (LDL-C) is an easily achievable and highly reliable modifiable risk factor for preventing cardiovascular disease (CVD), as validated by the unparalleled success of statins in the last three decades. However, the 2021 American Heart Association (AHA) statistics show a worrying upward trend in CVD deaths, calling into question the widely held belief that statins and available adjuvant therapies can fully resolve the CVD problem. Human biomarker studies have shown that indicators of inflammation, such as human C-reactive protein (hCRP), can serve as a reliable risk predictor for CVD, independent of all traditional risk factors. Oxidized cholesterol mediates chronic inflammation and promotes atherosclerosis, while anti-inflammatory therapies, such as an anti-interleukin-1 beta (anti-IL-1ß) antibody, can reduce CVD in humans. Cholesterol removal from artery plaques, via an athero-protective reverse cholesterol transport (RCT) pathway, can dampen inflammation. Phosphatidylinositol 4,5-bisphosphate (PIP2) plays a role in RCT by promoting adenosine triphosphate (ATP)-binding cassette transporter A1 (ABCA1)-mediated cholesterol efflux from arterial macrophages. Cholesterol crystals activate the nod-like receptor family pyrin domain containing 3 (Nlrp3) inflammasome in advanced atherosclerotic plaques, leading to IL-1ß release in a PIP2-dependent fashion. PIP2 thus is a central player in CVD pathogenesis, serving as a critical link between cellular cholesterol levels, ATP-binding cassette (ABC) transporters, and inflammasome-induced IL-1ß release.

PANoptosis-like cell death in ischemia/reperfusion injury of retinal neurons.

PANoptosis is a newly identified type of regulated cell death that consists of pyroptosis, apoptosis, and necroptosis, which simultaneously occur during the pathophysiological process of infectious and inflammatory diseases. Although our previous literature mining study suggested that PANoptosis might occur in neuronal ischemia/reperfusion injury, little experimental research has been reported on the existence of PANoptosis. In this study, we used in vivo and in vitro retinal neuronal models of ischemia/reperfusion injury to investigate whether PANoptosis-like cell death (simultaneous occurrence of pyroptosis, apoptosis, and necroptosis) exists in retinal neuronal ischemia/reperfusion injury. Our results showed that ischemia/reperfusion injury induced changes in morphological features and protein levels that indicate PANoptosis-like cell death in retinal neurons both in vitro and in vivo. Ischemia/reperfusion injury also significantly upregulated caspase-1, caspase-8, and NLRP3 expression, which are important components of the PANoptosome. These results indicate the existence of PANoptosis-like cell death in ischemia/reperfusion injury of retinal neurons and provide preliminary experimental evidence for future study of this new type of regulated cell death.

Carbon monoxide ameliorates lipopolysaccharide-induced acute lung injury via inhibition of alveolar macrophage pyroptosis.

Carbon monoxide (CO) has been reported to exhibit a therapeutic effect in lipopolysaccharide (LPS)-induced acute lung injury (ALI). However, the precise mechanism by which CO confers protection against ALI remains unclear. Pyroptosis has been recently proposed to play an essential role in the initiation and progression of ALI. Thus, we investigated whether pyroptosis is involved in the protection of CO against ALI and its underlying mechanism. First, an LPS-induced ALI mouse model was established. To determine the role of pyroptosis, we evaluated histological changes and the expression levels of cleaved caspase-11, N-gasdermin D (GSDMD), and IL-1ß in lung tissues, which are the indicators of pyroptosis. Inhalation of CO exhibited protective effects on LPS-induced ALI by decreasing TNF-α and IL-10 expression and ameliorating pathological changes in lung tissue. In vitro, CO significantly reduced the expression of cleaved caspase-11, N-GSDMD, IL-1ß, and IL-18. In addition, it increased nuclear factor E2-related factor 2 (NRF-2) expression in a time-dependent manner in RAW 264.7 cells and decreased N-GSDMD expression. The expression of cleaved GSDMD and release of LDH were increased after treatment with a specific NRF-2 inhibitor, ML385, indicating that NRF-2 mediates the inhibition of pyroptosis by CO. Taken together, these results demonstrated that CO upregulated NRF-2 to inhibit pyroptosis and subsequently ameliorated LPS-induced ALI.

Mechanism of Shenqi Yiliu Prescription Combined with Cisplatin on H22 Liver Cancer-bearing Mice Based on NLRP3/Caspase-1/GSDMD Pyroptosis Pathway / 中国实验方剂学杂志

ObjectiveTo explore the anti-tumor effect and mechanism of Shenqi Yiliu prescription in the intervention of pyroptosis. MethodTen male BALB/c mice were randomly selected and assigned to the blank group. The remaining 40 mice underwent the induction of the liver cancer xenograft model. After 5 days of modeling， 40 surviving mice were randomly divided into model group， cisplatin group ［2.5×10-3 g·kg-1·（3 d）-1］， Shenqi Yiliu prescription group （27 g·kg-1·d-1）， and a combination group （Shenqi Yiliu prescription group + cisplatin）. The mice in the blank group and the model group were treated with an equal volume of normal saline for 10 days. The general conditions of mice in each group were observed. After the intervention， the tumor weight of the mice was weighed and the tumor inhibition rate was calculated. Hematoxylin-eosin （HE） staining was used to observe the pathological changes in tumor tissues. The levels of mouse liver function indicators， including alanine aminotransferase （ALT） and aspartate aminotransferase （AST） were detected. The TdT-mediated dUTP-biotin nick end labeling （TUNEL） assay was used to detect DNA damage in mouse tumor tissue cells. Immunohistochemistry （IHC）， immunofluorescence （IF）， and Western blot were used to detect the protein expression levels of NOD-like receptor protein 3 （NLRP3）， cysteinyl aspartate-specific protease-1 （Caspase-1）， and gasdermin D （GSDMD） in tumor tissues. The levels of interleukin-1β （IL-1β） and interleukin-18 （IL-18） in tumor tissues were detected by enzyme-linked immunosorbent assay （ELISA）. ResultCompared with the mice in the blank group， those in the model group were in a poor mental state， sleepy， and lazy， and their fur color was dull， with increased levels of serum ALT and AST in liver function tests （P<0.01）. Compared with the model group， the groups with drug intervention showed improved mental state， inhibited tumor growth to varying degrees， and decreased tumor weight， and the tumor inhibition rate in the combination group was the highest （P<0.01）. HE staining showed that the pathological and morphological lesions of the tumor tissues in the model group were significant， while those in all groups with drug intervention were improved to a certain extent. The karyolysis and nuclear rupture in the Shenqi Yiliu prescription group and the combination group were more significant. In the liver function test， the serum ALT and AST levels of mice in the Shenqi Yiliu prescription group and the combination group decreased （P<0.01）， and the inflammatory factors IL-1β and IL-18 in each group with drug intervention decreased （P<0.05， P<0.01）. Among them， the declining trend of IL-1β and IL-18 in the Shenqi Yiliu prescription group was the most significant （P<0.01）. TUNEL staining showed that the positive TUNEL staining in each group with drug intervention decreased after intervention （P<0.05， P<0.01）， especially the cisplatin group and Shenqi Yiliu prescription group （P<0.01）. Western blot， IHC， and IF found that the protein expression levels of NLRP3， Caspase-1， and GSDMD in each group with drug intervention decreased （P<0.05， P<0.01）. Compared with the mice in the cisplatin group， those in the Shenqi Yiliu prescription group and the combination group had better mental state and regular tumor morphology， and the tumor weight of the mice in the combination group decreased （P<0.05）. The levels of ALT and AST in the Shenqi Yiliu prescription group decreased （P<0.05）， and the levels of IL-1β and IL-18 in the Shenqi Yiliu prescription group and the combination group decreased （P<0.05， P<0.01）， especially in the combination group （P<0.01）. The results of IHC showed that the expression of GSDMD protein in the tumor tissues of mice in the combination group was reduced （P<0.01）. IF detection showed that the expression of NLRP3 in the tumor tissues of the Shenqi Yiliu prescription group was reduced （P<0.01）. The results of Western blot showed that the expression level of NLRP3 protein in the Shenqi Yiliu prescription group and the combination group decreased （P<0.01）， and the expression level of Caspase-1 protein in the combination group decreased （P<0.01）. The decrease in GSDMD protein expression was not significant， and the difference was not statistically significant. ConclusionShenqi Yiliu prescription combined with cisplatin has an obvious anti-tumor effect， which may be achieved by down-regulating the NLRP3/Caspase-1/GSDMD inflammatory pyroptosis pathway to inhibit cell pyroptosis， and relieve the inflammatory response in mice with liver cancer.

Regulation of Pyroptosis in Gastric Cancer by Traditional Chinese Medicine： A Review / 中国实验方剂学杂志

Pyroptosis， a new type of inflammatory programmed cell death， is different from apoptosis， necrosis， cytosis， ferroptosis， and autophagy. Pyroptosis is dependent on the activation of cysteine aspartate-specific protease （Caspase）， which cleaves key mediator proteins to form pores in the cell membrane and induces the maturation and release of the proinflammatory cytokines interleukin-1β and interleukin-18 into the extracellular environment， resulting in a cascade of inflammatory reactions. Gastric cancer as a malignant tumor of the digestive tract is refractory and has poor prognosis， and the chemoradiotherapy of this disease may lead to a variety of complications. At present， the pathogenesis of gastric cancer remains unclear. Studies have proved that pyroptosis is associated with the occurrence and development of gastric cancer， which has attracted wide attention. Pyroptosis is a double-edged sword for gastric cancer. On the one hand， it can release the contents of proinflammatory cells to amplify or maintain inflammation and induce the "inflammation-cancer" transformation of cells. On the other hand， pyroptosis can enhance the sensitivity of drugs for chemotherapy to improve the therapeutic effect and survival. In recent years， the anti-tumor mechanism of traditional Chinese medicine （TCM） has become a research hotspot as TCM has demonstrated significant effects in clinical application. Therefore， the regulation of pyroptosis by TCM may be a new direction for the treatment of gastric cancer in the future. Based on the available studies， this paper introduces the roles of pyroptosis-associated key proteins in the occurrence and development of gastric cancer. Furthermore， this paper summarizes the effects of TCM prescriptions and active ingredients on alleviating gastric mucosal damage， reducing the incidence of gastric cancer， and preventing tumor metastasis and recurrence by mediating pyroptosis pathways， aiming to provide new ideas for deciphering the mechanism of pyroptosis and exploring the TCM treatment of gastric cancer in the future.

Natural Medicinal Components Mediating Pyroptosis by GSDMs in Anti-tumor Therapy： A Review / 中国实验方剂学杂志

Pyroptosis， an atypical new cell death mode other than apoptosis and necrosis， has been discovered in recent years. Pyroptosis depends on the cleavage of gasdermins （GSDMs） by Caspases. The activated GSDMs act on the plasma membrane to form a perforation， which results in cell lysis and triggers inflammation and immune response. Pyroptosis can be induced by four distinct signaling pathways， including canonical and non-canonical inflammasome pathways， apoptosis-associated Caspases-mediated pathway， and granzyme pathway. In these signaling pathways， GSDMs are the executors of pyroptosis. Pyroptosis is associated with the death of tumor cells and the inflammatory damage of normal tissues. Recent studies have demonstrated that moderate pyroptosis can lead to tumor cell death to exert an anti-tumor effect， and meanwhile stimulate the tumor immune microenvironment， while it can promote tumor development. Despite the good performance， drug-based anti-tumor therapies such as tumor immunotherapy， chemotherapy， and targeted therapy have some shortcomings such as drug resistance， recurrence， and damage to normal tissues. The latest research shows that a variety of natural compounds have anti-tumor effects in the auxiliary treatment of tumors by mediating the pyroptosis pathways in a multi-target and multi-pathway manner， which provide new ideas for the study of anti-tumor therapy. We reviewed the molecular mechanism of pyroptosis and the regulatory role of pyroptosis in tumors and tumor immune microenvironment， and summarized the recent research progress in the natural medicinal components regulating pyroptosis in anti-tumor therapy， with a view to providing ideas for the research on the anti-tumor therapy based on pyroptosis.

Pyroptosis associated with immune reconstruction failure in HIV-1- infected patients receiving antiretroviral therapy: a cross-sectional study.

BACKGROUND: Highly active anti-retroviral therapy (HAART) can successfully suppress human immunodeficiency virus (HIV) viral replication and reconstruct immune function reconstruction in HIV-1-infected patients. However, about 15-30% of HIV-1-infected patients still fail to recover their CD4+ T cell counts after HAART treatment, which means immune reconstruction failure. Pyroptosis plays an important role in the death of CD4+ T cells in HIV-1- infected patients. The study aims to explore the association between the expression of pyroptosis in peripheral blood and immune function reconstruction in HIV-1- infected patients. METHODS: One hundred thirty-five HIV-1-infected patients including immunological non-responders (INR) group, immunological responders (IR) group and normal immune function control (NC) group were analyzed. The expression of GSDMD and Caspase-1 in peripheral blood of HIV-1-infected patients were measured by qPCR. The concentrations of GSDMD, Caspase-1, IL-1ß and IL-18 in the peripheral serum were quantified by ELISA. The associations between the expression of pyroptosis in peripheral blood and immune function reconstruction were analyzed using multivariate logistic models. RESULTS: The relative expression of GSDMD mRNA and caspase-1 mRNA in peripheral blood, as well as the expression of IL-18 cytokine in the INR, were significantly higher than those in the IR and NC (P < 0.05). There was no significant difference in the expression of IL-1ß cytokine (P > 0.05). Multivariate logistic analysis showed that the patients with baseline CD4+ T cell counts less than 100 cells/µL (aOR 7.051, 95% CI 1.115-44.592, P = 0.038), high level of expression of Caspase-1mRNA (aOR 2.803, 95% CI 1.065-7.377, P = 0.037) and IL-18 cytokine (aOR 10.131, 95% CI 1.616-63.505, P = 0.013) had significant poor CD4+ T cell recovery. CONCLUSIONS: The baseline CD4+ T cell counts less than 100 cells/µL, high relative expression of Caspase-1 mRNA, and high expression of IL-18 cytokine are associated factors that affect the reconstruction of immune function.

[Effect of electroacupuncture preconditioning on expression of Gasdermin D, Caspase-1 and IL-1ß in rats with myocardial ischemia reperfusion injury].

OBJECTIVE: To observe the effect of electroacupuncture(EA) preconditioning on expression of Caspase-1, Gasdermin D(GSDMD) and interleukin-1ß(IL-1ß) in myocardial tissue of myocardial ischemia reperfusion injury (MIRI) rats in order to explore its underlying mechanisms in resisting MIRI. METHODS: Forty male rats were randomly divided into 4 groups: normal control (normal), sham operation (sham), MIRI model and EA groups. The MIRI model was established by ligation of the left anterior descending branch of the left coronary artery for 30 min and perfusion. EA (2 Hz/100 Hz, 1 mA) was applied to bilateral "Neiguan" (PC6) for 20 min, once a day for 3 consecutive days. The echocardiography was used to analyze the left ventricular end-diastolic dimension (LVEDD), left ventricular end-systolic dimension (LVESD) and left ventricular ejection fraction (LVEF, by using Teichholz formula) 4 h after modeling. The myocardial TTC staining was used to observe the proportion of the infarct area, and Western blot was used to detect the expression levels of GSDMD, Caspase-1, IL-1ß proteins in the myocardium. RESULTS: Compared with the normal group, the immunoactivity of GSDMD was increased in the sham group (P<0.05). Compared with the sham group, the LVEF was significantly decreased (P<0.000 1), while the myocardial infarction area, immunoactivity of GSDMD, and the expression levels of Caspase-1, GSDMD and IL-1ß proteins were considerably increased in the model group (P<0.000 1, P<0.001). In comparison with the model group, the decreased ejection fraction and the increased myocardial infarction area, and Caspase-1, GSDMD and IL-1ß expression were reversed in the EA group (P<0.001, P<0.000 1, P<0.01). CONCLUSION: EA preconditioning may ameliorate myocardial injury in MIRI rats which may be associated with its function in down-regulating the expression of myocardial Caspase-1 protein to reduce cardiomyocyte pyroptosis.

Differential Expression and Copy Number Variation of Gasdermin (GSDM) Family Members, Pore-Forming Proteins in Pyroptosis, in Normal and Malignant Serous Ovarian Tissue.

Gasdermins (GSDM) are members of a family of pore-forming effector proteins which lead to membrane permeabilization and pyroptosis, a lytic cell death with pro-inflammatory characteristics. Recently, two members of the gasdermin family, gasdermin B (GSDMB) and gasdermin E (GSDME), were shown to suppress tumor growth, through the involvement of cytotoxic lymphocytes. Other studies also reported the important functions of gasdermins in various cancer types including gastric cancer, hepatocarcinoma, and cervix and breast cancer. However, gasdermins have not been previously studied in the context of serous ovarian cancer. Here, we showed that gasdermin D (GSDMD) and gasdermin C (GSDMC) expression increases in serous ovarian cancer; in contrast, the expression of GSDME and PJVK (Pejvakin, DFNB59) is downregulated, compared to healthy ovaries, in multiple independent gene expression datasets. We found that copy number gains are highly frequent (present in approximately 50% of patients) in genes encoding GSDMD and GSDMC in ovarian cancer, in line with their upregulated expression in serous ovarian cancer. Moreover, we observed that the expression of GSDMB and GSDMD, but not of GSDME, is different among several histotypes of epithelial ovarian cancer. Therefore, we propose that differential expression and copy number variations of certain gasdermins might be associated with the development of serous ovarian cancer, in which different members of the family have distinct functions; however, further research is required in in vivo models to understand how changes in gasdermin family members mechanistically contribute to serous ovarian cancer.

Effect and mechanism of phospholipid scramblase 4 (PLSCR4) on lipopolysaccharide (LPS)-induced injury to human pulmonary microvascular endothelial cells.

BACKGROUND: Previous experiments revealed phospholipid scramblase 4 (PLSCR4) mRNA to be significantly increased in a lipopolysaccharide (LPS)-induced acute respiratory distress syndrome (ARDS) model of human pulmonary microvascular endothelial cells (HPMECs); however, the effect of PLSCR4 and its mechanism have not been reported to date. The PLSCR family is thought to mediate the transmembrane movement of phospholipids (PS), and has been found to be involved in pyroptosis through combing with gasdermin D (GSDMD). We therefore speculated that PLSCR4 may contribute to cell death via pyroptosis. METHODS: To investigate the effect and mechanism of PLSCR4 in ARDS, we constructed an in vitro model of LPS-induced ARDS in HPMECs transfected with PLSCR4 small interfering RNA (siRNA) or scramble siRNA (sc siRNA). After 4 h of LPS stimulation, western blotting, immunoprecipitation, enzyme-linked immunosorbent assay (ELISA), tracer flux assays, and fluorescence assays were used to study the relationship between PLSCR4 and pyroptosis with regards to their impact on ARDS. We also established an ARDS mouse model which was pretreated with a liquid complex of PLSCR4 siRNA/sc siRNA-lipofectamine 2000 through the fundus venous plexus. Finally, we used DNA pull-down and protein profiling to study the potential transcription factor of PLSCR4. RESULTS: It was found that when the expression of PLSCR4 was elevated, the concentration of interleukin 1 beta (IL-1ß) and IL-18 decreased, along with barrier damage (P<0.05). Furthermore, HPMEC injury was reduced with more distribution of PS and N-terminal cleavage product (GSDMD-NT) of GSDMD on the external side of cell membrane. However, the pyroptosis-relevant proteins of GSDMD and caspase-1 were not obviously changed (P<0.05); we further found that when PLSCR4 was depressed, the lung injury was aggravated in the mice. In the DNA pull-down assay, P62280 remarkably increased, which suggested that P62280 might be the transcription factor for PLSCR4. CONCLUSIONS: PLSCR4 alleviated pyroptosis by transporting PS to the outside of the membrane, blocking the formation of pyroptosis pores composed of GSDMD. Moreover, P62280 might be the transcription factor of PLSCR4. These insults may provide useful insights into the clinical treatment of ARDS.

LPS Induces Active HMGB1 Release From Hepatocytes Into Exosomes Through the Coordinated Activities of TLR4 and Caspase-11/GSDMD Signaling.

High-mobility group box-1 (HMGB1), a ubiquitous nuclear protein, acts as a late mediator of lethality when released extracellularly during sepsis. The major source of circulating HMGB1 in sepsis is hepatocytes. However, the mechanism of HMGB1 release of hepatocytes during sepsis is not very clear. We have previously shown that bacterial endotoxin [lipopolysaccharide (LPS)] sensing pathways, including Toll-like receptor (TLR)4 and caspase-11, regulate hepatocyte HMGB1 release in response to LPS. Here, we report the novel function of caspase-11 and gasdermin D (GsdmD) in LPS-induced active HMGB1 released from hepatocytes. HMGB1 release during endotoxemia was caspase-11/GsdmD dependent via an active way in vivo and in vitro. Caspase-11/GsdmD was responsible for HMGB1 translocation from nucleus to the cytoplasm via calcium changing-induced phosphorylation of calcium-calmodulin kinase kinase (camkk)ß during endotoxemia. Cleaved GsdmD accumulated on the endoplasmic reticulum, suggesting this may lead to calcium leak and intracellular calcium increase. Furthermore, we investigated that exosome was an important pathway for HMGB1 release from hepatocytes; this process was dependent on TLR4, independent of caspase-11 and GsdmD in vivo and in vitro. These findings provide a novel mechanism that TLR4 signaling results in an increase in caspase-11 expression, as well as increased exosome release, while caspase-11/GsdmD activation/cleavage leads to accumulation of HMGB1 in the cytoplasm through a process associated with the release of calcium from the endoplasmic reticulum and camkkß activation.

Induction of Pyroptosis and Its Implications in Cancer Management.

Pyroptosis is a gasdermins mediated programmed cell death, which has been widely studied in inflammatory disease models. Recently, there are growing evidences that pyroptosis can be chemically induced in cancer cells without any bacterial or viral infection. Pyroptosis may affect all stages of carcinogenesis and has become a new topic in cancer research. In this review, we first briefly introduced pyroptosis. In the subsequent section, we discussed the induction of pyroptosis in cancer and its potential role as a promising target for cancer therapy. In addition, the biological characteristics of gasdermin D (GSDMD) and gasdermin E (GSDME), two important pyroptosis substrates, and their prognostic role in cancer management were reviewed. These results help us to understand the pathogenesis of cancer and develop new drugs, which based on pyroptosis modulation, for cancer patients.

Research progress in Gasdermin family proteins and their association with diseases / 中华微生物学和免疫学杂志

Gasdermin family (GSDMs), consisting of six proteins (GSDMA, GSDMB, GSDMC, GSDMD, GSDME and DFNB59) in humans and ten proteins (GSDMA1-3, GSDMC1-4, GSDMD, GSDME and DFNB59) in mice, might be involved in multiple physiological and pathological processes, including epithelial cell development, apoptosis, inflammation, carcinogenesis and immune-related diseases. Recent studies confirmed GSDMD, which containing an N-terminal domain with pore-forming activity and a C-terminal domain with structural autoinhibition, as a crucial substrate of inflammatory caspases in pyroptosis, pioneering a new area for structural and functional research on Gasdermin family proteins. This review will summarize the latest progress in the structures, functions and association with diseases of several Gasdermin family proteins.

Research progress in Gasdermin family proteins and their association with diseases / 中华微生物学和免疫学杂志

Gasdermin family (GSDMs), consisting of six proteins (GSDMA, GSDMB, GSDMC, GSDMD, GSDME and DFNB59) in humans and ten proteins (GSDMA1-3, GSDMC1-4, GSDMD, GSDME and DFNB59) in mice, might be involved in multiple physiological and pathological processes, including ep-ithelial cell development, apoptosis, inflammation, carcinogenesis and immune-related diseases. Recent studies confirmed GSDMD, which containing an N-terminal domain with pore-forming activity and a C-termi-nal domain with structural autoinhibition, as a crucial substrate of inflammatory caspases in pyroptosis, pio-neering a new area for structural and functional research on Gasdermin family proteins. This review will sum-marize the latest progress in the structures, functions and association with diseases of several Gasdermin fam-ily proteins.