Humans ; Pyroptosis/physiology* ; Pore Forming Cytotoxic Proteins

Brain Ischemia ; pathology ; physiopathology ; Humans ; Neoplasm Proteins ; metabolism ; Pyroptosis ; physiology ; Signal Transduction ; physiology

Necroptosis is one of the regulated cell death, which involves receptor interacting protein kinase (RIPK) 1/RIPK3/mixed lineage kinase domain like protein (MLKL) signaling pathway. Among them, MLKL is the final execution of necroptosis. The formation of RIPK1/RIPK3/MLKL necrosome induces the phosphorylated MLKL, and the activated MLKL penetrates into the membrane bilayer to form membrane pores, which damages the integrity of the membrane and leads to cell death. In addition to participating in necroptosis, MLKL is also closely related to other cell death, such as NETosis, pyroptosis, and autophagy. Therefore, MLKL is involved in the pathological processes of various diseases related to abnormal cell death pathways (such as cardiovascular diseases, neurodegenerative diseases and cancer), and may be a therapeutic target of multiple diseases. Understanding the role of MLKL in different cell death can lay a foundation for seeking various MLKL-related disease targets, and also guide the development and application of MLKL inhibitors.
Protein Kinases/metabolism* ; Necroptosis/physiology* ; Receptor-Interacting Protein Serine-Threonine Kinases ; Signal Transduction ; Pyroptosis ; Apoptosis

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

This study aims to investigate the effects and the molecular mechanism of Huangdi Anxiao Capsules(HDAX)-containing serum in protecting the rat adrenal pheochromocytoma(PC12) cells from diabetes-associated cognitive dysfunction induced by high glucose and whether the mechanism is related to the regulation of NOD-like receptor thermal protein domain associated protein 3(NLRP3)-mediated pyroptosis. The PC12 cell model of diabetes-associated cognitive dysfunction induced by high glucose was established and mcc950 was used to inhibit NLRP3. PC12 cells were randomized into control, model, HDAX-containing serum, mcc950, and HDAX-containing serum+mcc950 groups. Methyl thiazolyl tetrazolium(MTT) assay was employed to determine the viability, and Hoechst 33258/PI staining to detect pyroptosis of PC12 cells. Enzyme-linked immunosorbent assay(ELISA) was employed to measure the levels of interleukin-1 beta(IL-1β) and IL-18. Western blot was employed to determine the protein levels of postsynaptic density protein 95(PSD-95), NLRP3, apoptosis-associated speck-like protein containing a CARD(ASC), gasdermin D(GSDMD), GSDMD-N, and cleaved cysteinyl aspartate specific proteinase-1(caspase-1), and RT-PCR to determine the mRNA levels of NLRP3, ASC, GSDMD, and caspase-1. The immunofluorescence assay was adopted to measure the levels and distribution of NLRP3 and GSDMD-N in PC12 cells. Compared with the control group, the model group showed decreased cell proliferation, increased PI positive rate, down-regulated protein level of PSD-95, up-regulated protein levels of NLRP3, ASC, GSDMD-N, GSDMD, and cleaved caspase-1, up-regulated mRNA levels of NLRP3, ASC, GSDMD, and caspase-1, and elevated levels of IL-1β and IL-18. Compared with the model group, HDAX-containing serum, mcc950, and the combination of them improved cell survival rate and morphology, decreased the PI positive rate, down-regulated the protein levels of NLRP3, ASC, GSDMD-N, GSDMD, and cleaved caspase-1 and the mRNA levels of NLRP3, ASC, GSDMD, and caspase-1, and promoted the secretion of IL-1β and IL-18. The findings demonstrated that HDAX-containing serum can inhibit the pyroptosis-mediated by NLRP3 and protect PC12 cells from the cognitive dysfunction induced by high glucose.
Rats ; Animals ; NLR Family, Pyrin Domain-Containing 3 Protein/metabolism* ; Interleukin-18 ; Pyroptosis/physiology* ; Diabetes Mellitus ; Caspases ; Glucose ; RNA, Messenger

OBJECTIVE: Pyroptosis is an inflammatory form of programmed cell death. This phenomenon has been recently reported to play an important role in radiation-induced normal tissue injury. Connexin43 (Cx43) is a gap junction protein that regulates cell growth and apoptosis. In this study, we investigated the effect of Cx43 on X-ray-induced pyroptosis in the human umbilical vein endothelial cells (HUVECs). METHODS: HUVECs, Cx43 overexpression, and Cx43 knockdown strains were irradiated with 10 Gy. Proteins were detected using western blot analysis. Cell pyroptosis was evaluated using the fluorescence-labeled inhibitor of caspase assay (FLICA) and propidium iodide staining through flow cytometry and confocal microscopy. Cell morphology and cytotoxicity were detected by scanning electron microscopy and lactate dehydrogenase release assay, respectively. RESULTS: Irradiation with 10 Gy X-ray induced pyroptosis in the HUVECs and reduced Cx43 expression. The pyroptosis in the HUVECs was significantly attenuated by overexpression of Cx43 as it decreased the level of active caspase-1. However, interference of Cx43 expression with siRNA significantly promoted pyroptosis by increasing the active caspase-1 level. Pannexin1 (Panx1), a gap junction protein regulates pyroptosis, and its cleaved form is used to evaluate channel opening and active state. The level of cleaved Panx1 in the HUVECs and Cx43 knockdown strains increased in the presence of X-ray, but decreased in the Cx43 overexpression strains. Furthermore, interference of Panx1 with siRNA alleviated the upregulation of pyroptosis caused by Cx43 knockdown. CONCLUSION Results suggest that single high-dose X-ray irradiation induces pyroptosis in the HUVECs. In addition, Cx43 regulates pyroptosis directly by activating caspase-1 or indirectly by cleaving Panx1.
Caspase 1 ; genetics ; metabolism ; Connexin 43 ; genetics ; metabolism ; Connexins ; genetics ; metabolism ; Gene Expression Regulation ; radiation effects ; Human Umbilical Vein Endothelial Cells ; physiology ; radiation effects ; Humans ; Nerve Tissue Proteins ; genetics ; metabolism ; Pyroptosis ; X-Rays ; adverse effects