Inflammatory injury of the intestine is often accompanied by symptoms such as damage to intestinal mucosa, increased intestinal permeability, and intestinal motility dysfunction. Inflammatory factors spread throughout the body via blood circulation, and can cause multi-organ failure. Pyroptosis is a newly discovered way of programmed cell death, which is mainly characterized by the formation of plasma membrane vesicles, cell swelling until the rupture of the cell membrane, and the release of cell contents, thereby activating a drastic inflammatory response and expanding the inflammatory response cascade. Pyroptosis is widely involved in the occurrence of diseases, and the underlying mechanisms for inflammation are still a hot spot of current research. The caspase-1 mediated canonical inflammasome pathway of pyroptosis and caspase-4/5/8/11-mediated non-canonical inflammasome pathway are closely related to the occurrence and development of intestinal inflammation. Therefore, investigation of the signaling pathways and molecular mechanisms of pyroptosis in intestinal injury in sepsis, inflammatory bowel diseases, infectious enteristic, and intestinal tumor is of great significance for the prevention and treatment of intestinal inflammatory injury.
Humans ; Pyroptosis ; Inflammasomes/metabolism* ; Apoptosis ; Caspase 1 ; Inflammation

OBJECTIVE: To study whether pyroptosis is involved in the bilirubin-induced injury of primary cultured rat cortical microglial cells. METHODS: Primary cultured rat cortical microglial cells were randomly administered with 30 μmol/L bilirubin (bilirubin group), 30 μmol/L bilirubin following 30 μmol/L VX-765 pretreatment (VX-765+bilirubin group), or an equal volume of dimethyl sulfoxide (control group). Modified MTT assay was used to measure the viability of microglial cells. Western blot was used to measure the expression of the pyroptosis-related proteins Caspase-1 and gasdermin D (GSDMD). Lactate dehydrogenase (LDH)-release assay was used to evaluate the cytotoxicity of microglial cells. EtBr/EthD2 with different molecular weights (394 Da/1 293 Da) was used to measure the size of plasma membrane pores. ELISA was used to measure the level of the inflammatory factor interleukin-1β (IL-1β) in culture supernatant. RESULTS: After bilirubin stimulation, the viability of microglial cells decreased and LDH release increased, both in a time-dependent manner. Compared with the control group, the bilirubin group had a significantly higher positive rate of small-molecule EtBr passing through the cell membrane (P<0.001), while there was no significant difference in the pass rate of large-molecule EthD2 between groups (P>0.05). The expression of activated Caspase-1 significantly increased at 0.5 hour after bilirubin stimulation (P<0.05), and that of activated GSDMD significantly increased at 6 hours after bilirubin stimulation (P<0.05). The release of IL-1β significantly increased at 6 hours after bilirubin stimulation and reached the peak at 24 hours (P<0.001). Compared with the bilirubin group, the VX-765+bilirubin group had a significant increase in cell viability (P<0.05) and significant reductions in the expression of activated GSDMD, the pass rate of EtBr, and the release of LDH and IL-1β (P<0.05). CONCLUSIONS Pyroptosis is involved in bilirubin-induced injury of primary cultured microglial cells.
Animals ; Bilirubin ; Caspase 1 ; Cell Survival ; Interleukin-1beta ; Pyroptosis ; Rats

OBJECTIVE: To investigate the molecular mechanism underlying the inhibitory effect of propofol on pyroptosis of macrophages. METHODS: Macrophages derived from bone marrow were extracted and divided into three groups: control group, LPS+ATP group and propofol+LPS+ATP group. The control group was not given any treatment; LPS+ATP group was given LPS 1 μg/mL stimulation for 4 h, then ATP 4 mM stimulation for 1 h; Propofol+LPS+ATP group was given propofol+LPS 1 μg/mL stimulation for 4 h, then ATP stimulation for 1 h. After treatment, the supernatant and cells of cell culture were collected. the cell activity was detected by CCK8 and flow cytometry. The inflammatory cytokines IL-1βand IL-18 were detected by Elisa. Western blot was used to detect the expression of caspase-1 protein and TLR4 on cell membran Immunohistochemical fluorescence was used to detect apoptosis of cells. RESULTS: LPS+ATP significantly decreased the viability of the macrophages and increased the cellular production of IL-1β and IL-18, activation of caspase-1 protein and the expression of TLR-4 on the cell membrane ( < 0.05). Treatment with propofol obviously reversed the changes induced by LPS+ATP. CONCLUSIONS LPS+ATP can induce pyroptosis of mouse bone marrow-derived macrophages, and propofol effectively inhibits such cell death, suggesting that propofol anesthesia is beneficial during operation and helps to regulate the immune function of in patients with sepsis.
Animals ; Caspase 1 ; Lipopolysaccharides ; Macrophages ; Mice ; Propofol ; Pyroptosis

BACKGROUND: Although pulmonary resection is the standard approach for the management of pulmonary metastases from soft tissue sarcoma, most of them are unresectable and chemotherapy remains the only option. The effectiveness of the cytotoxic drugs may be limited by the toxicities that occur before the therapeutic dose is reached. The regional administration of doxorubicin using pulmonary arterial perfusion in a rodent model can produce 10 to 25 times higher concentrations in the lung than systemic administration with minimal systemic toxicities. However, it is unclear whether a high concentration of doxorubicin has beneficial effects for killing cancer cells. MATERIAL AND METHOD: We studied this to evaluate the dose-dependent cytotoxic and apoptotic effects of doxorubicin on methylcholanthrene-induced rat fibrosarcoma(MCA) cells. This study examined the cytotoxicity and apoptosis-related gene expressions(Fas, FasL, Bax, caspase 1, caspase 2, caspase 8, Bcl-2, Bcl-xL, Bcl-xS) in MCA cells after 24 hours exposure to various concentrations of doxorubicin such as 1, 5, 10, 50, and 100 micrometer. RESULT: Dose-dependent cytotoxicity was observed after 24 hours exposure to doxorubicin. However, peak apoptosis after 24 hours exposure was observed at 5 micrometer of doxorubicin. Above 5 micrometer, apoptotic activity was decreased with dose-increment. All mRNA levels of apoptosis-related genes after 24 hours exposure were up-regulated above the control level at 1 micrometer of doxorubicin and then decreased by doxorubicin dose-increment except caspase 8, which showed higher levels than the control level at 5 micrometer. Apoptosis-related protein levels were highest at 1 micrometer of doxorubicin and then decreased by doxorubicin dose-increment. However, Bax and Bcl-xL proteins steadily showed higher levels than the control throughout the different concentrations of doxorubicin. CONCLUSION: These results suggest that apoptosis is the main cytotoxic mechanism in low concentrations of doxorubicin in MCA cells and apoptosis-related genes, such as Bax, caspase 8, a can kill MCA cells, even when apoptosis is inhibited, and have its propriety for achieving much cytotoxicity against MCA cells.
Animals ; Apoptosis* ; bcl-X Protein ; Caspase 1 ; Caspase 2 ; Caspase 8 ; Doxorubicin* ; Drug Therapy ; Fibrosarcoma ; Homicide ; Lung ; Neoplasm Metastasis ; Perfusion ; Rats* ; RNA, Messenger ; Rodentia ; Sarcoma

Chronic inflammation is a critical modulator of carcinogenesis through secretion of inflammatory cytokines, which leads to the formation of an inflammatory microenvironment. In this process, the inflammasome plays an important role in the expression and activation of interleukin (IL)-1β and IL-18 to promote cancer development. The inflammasome is a multiprotein complex consisting of several nucleotide-binding domain and leucine-rich repeat containing receptor, adaptor proteins, and caspase 1 (CASP1). It senses the various intracellular (damage-associated molecular patterns) and extracellular (pathogen-associated molecular patterns) stimuli. A primed inflammasome recruits adaptor proteins, activates CASP1 to enhance the proteolytic cleavage of pro-IL-1β and IL-18, and sends the signal to respond to each insult. Depending on stimuli and cell contexts, several inflammasomes are closely associated with the initiation and promotion of carcinogenesis. In contrast, inflammasomes also show an ambivalent effect on carcinogenesis by enhancing inflammatory cell death (pyroptosis) and repairing damaged tissues. Although the inflammasome plays a controversial role in carcinogenesis, it may be a promising target for human cancer prevention and treatment. A more in-depth study on the role of the inflammasome in carcinogenesis, based on stimuli, cell contexts, and cancer stages, can lead to the development of novel therapeutic strategies against malignant human cancers.
Carcinogenesis ; Caspase 1 ; Cell Death ; Cytokines ; Humans ; Inflammasomes* ; Inflammation ; Interleukin-18 ; Interleukins

OBJECTIVETo investigate the expression and significance of caspase-1 in normal and hyperplastic prostate tissues.

METHODSTwenty-eight paraffin-embedded sections, including 21 benign prostatic hyperplasia (BPH) and 7 normal prostate tissue samples, were investigated immunohistochemically for caspase-1.

RESULTSThe rate of caspase-1 expression in the BPH tissues was 71.4% (15/21 ) while that in the normal prostate tissues was 100%. The expression level of caspase-1 in both epithelial cells and interstitial cells of the hyperplastic prostate tissues was obviously lower than that of the normal prostate tissues (P < 0.01). Within the BPH tissues, the expression level of caspase-1 in the epithelial cells was higher than in the interstitial cells, and the difference was statistically significant (P < 0.01).

CONCLUSIONThe expression of caspase-1 is dramatically reduced in the hyperplastic prostate tissues, which indicates that the decline of caspase-1-dependent apoptosis might be involved in the progress of benign prostatic hyperplasia.

Apoptosis ; physiology ; Caspase 1 ; biosynthesis ; Humans ; Immunohistochemistry ; Male ; Prostate ; enzymology ; Prostatic Hyperplasia ; enzymology ; pathology

Apoptotic protease activating factor-1 (Apaf1) is an essential factor in intrinsic mitochondrial pathway of apoptosis activation. Apaf1 leads to the formation of apoptosome, which then proteolytically activates caspase-9. The activated caspase-9 opens the downstream signal of caspases to execute programmed cell death. Apaf-1 is important for tumor suppression and drug resistance because it plays a central role in DNA damage-induced apoptosis. Inactivation of the Apaf-1 gene is implicated in disease progression and chemoresistance of some malignancies. Further research on the Apaf-1 will contribute to develop a new type of approach to anti-cancer drugs, which might have good prospect in clinical practice. In this paper, the structure and function of Apaf-1, the mechanism involved in Apaf-1 signaling pathway, and application of Apaf-1 in tumor therapy were reviewed.
Apoptosis ; Apoptotic Protease-Activating Factor 1 ; metabolism ; Caspase 9 ; metabolism ; Humans ; Neoplasms ; therapy ; Signal Transduction

Sphingosine kinase 1 and its product, sphingosine 1-phosphate (S1P), as well as their receptors, have been implicated in inflammatory responses. The functions of receptors S1P₁ and S1P₂ on cell motility have been investigated. However, the function of S1P₃ has been poorly investigated. In this study, the roles of S1P₃ on inflammatory response were investigated in primary perito-neal macrophages. S1P₃ receptor was induced along with sphingosine kinase 1 by stimulation of lipopolysaccharide (LPS). LPS treatment induced inflammatory genes, such iNOS, COX-2, IL-1β, IL-6 and TNF-α. TY52156, an antagonist of S1P₃ suppressed the induction of inflammatory genes in a concentration dependent manner. Suppression of iNOS and COX-2 induction was further confirmed by western blotting and NO measurement. Suppression of IL-1β induction was also confirmed by western blotting and ELISA. Caspase 1, which is responsible for IL-1β production, was similarly induced by LPS and suppressed by TY52156. Therefore, we have shown S1P₃ induction in the inflammatory conditions and its pro-inflammatory roles. Targeting S1P₃ might be a strategy for regulating inflammatory diseases.
Blotting, Western ; Caspase 1 ; Cell Movement ; Enzyme-Linked Immunosorbent Assay ; Inflammation ; Interleukin-6 ; Macrophages ; Phosphotransferases ; Sphingosine

OBJECTIVES: To observe the electrophysiological changes of astrocytes in the process of hyperoxia induced apoptosis and analyze the relationship between electrophysiological characteristics and morphological changes. METHODS: Astrocytes were exposed to 90% hyperoxia for 12-72 h. The electrophysiological characteristics of astrocytes in each group were detected by patch clamp technique, and the morphological characteristics of astrocytes were observed at the same time. Then the same batch of astrocytes were collected, and the expression levels of caspase-1, caspase-3, gasdermin D (GSDMD) and gasdermin E (GSDME) were detected by Western blotting. RESULTS: From 12 h to 72 h after hyperoxia exposure, the inward current was significantly lower than that of the control group (<0.05), while the outward current was significantly decreased at 12 h and increased at 48 h (<0.05). There was no significant difference between 24 h or 72 h after hyperoxia exposure and the control group (>0.05). At each time point, the morphology of cells changed correspondingly. Western blotting showed that the expression of caspase-1 was increased significantly at 24 h and decreased significantly at 72 h after hyperoxia exposure (<0.05); the expression of GSDMD was increased at 12 h and decreased gradually from 24 h to 72 h after hyperoxia exposure (<0.05); the expression of caspase-3 did not change significantly at 12 h and 24 h after hyperoxia exposure (>0.05), but began to decrease at 48 h (<0.05); GSDME increased gradually at 24 h after hyperoxia exposure (<0.05). CONCLUSIONS Under hyperoxia exposure, the ion channels of astrocytes are damaged, which can maintain the dysfunction of ion homeostasis, activate GSDME, induce the damaged cells to break away from the apoptotic pathway, and mediate the pyroptosis.
Apoptosis ; Astrocytes ; Caspase 1 ; Humans ; Hyperoxia ; Intracellular Signaling Peptides and Proteins ; Neoplasm Proteins ; Phosphate-Binding Proteins ; Pyroptosis

Pyroptosis, an inflammatory caspase-dependent programmed cell death, plays a vital role in maintaining tissue homeostasis and activating inflammatory responses. Orthodontic tooth movement (OTM) is an aseptic force-induced inflammatory bone remodeling process mediated by the activation of periodontal ligament (PDL) progenitor cells. However, whether and how force induces PDL progenitor cell pyroptosis, thereby influencing OTM and alveolar bone remodeling remains unknown. In this study, we found that mechanical force induced the expression of pyroptosis-related markers in rat OTM and alveolar bone remodeling process. Blocking or enhancing pyroptosis level could suppress or promote OTM and alveolar bone remodeling respectively. Using Caspase-1^-/- mice, we further demonstrated that the functional role of the force-induced pyroptosis in PDL progenitor cells depended on Caspase-1. Moreover, mechanical force could also induce pyroptosis in human ex-vivo force-treated PDL progenitor cells and in compressive force-loaded PDL progenitor cells in vitro, which influenced osteoclastogenesis. Mechanistically, transient receptor potential subfamily V member 4 signaling was involved in force-induced Caspase-1-dependent pyroptosis in PDL progenitor cells. Overall, this study suggested a novel mechanism contributing to the modulation of osteoclastogenesis and alveolar bone remodeling under mechanical stimuli, indicating a promising approach to accelerate OTM by targeting Caspase-1.
Animals ; Humans ; Mice ; Rats ; Bone Remodeling/physiology* ; Caspase 1 ; Periodontal Ligament ; Pyroptosis ; Tooth Movement Techniques