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Pyroptosis is a form of programmed cell death associated with antimicrobial responses during inflammation. In this process, immune cells that recognize certain danger signals within themselves produce cytokines, swell, burst and die. This releases the cytokines, attracts other immune cells to fight the infection and contributes to inflammation. Some examples of pyroptosis include salmonella-infected macrophages and abortively HIV-infected T helper cells. The initiation of pyroptosis is caused by the recognition of flagellin components of Salmonella and Shigella species (and similar pathogen-associated molecular patterns (PAMPs) in other microbial pathogens) by NOD-like receptors (NLRs). These receptors function like plasma membrane Toll-like receptors (TLRs), but recognise antigens located within the cell rather than outside of it. In contrast to apoptosis, pyroptosis requires the function of the enzyme caspase-1. Caspase-1 is activated during pyroptosis by a large supramolecular complex termed the pyroptosome (also known as an inflammasome). Only one large pyroptosome is formed in each macrophage, within minutes after infection. Biochemical and Mass Spectroscopic analysis revealed that this pyroptosome is largely composed of dimers of the adaptor protein ASC (apoptosis-associated speck protein containing a CARD or Caspase activation and recruitment domain). Unlike apoptosis, pyroptosis results in the release of damage-associated molecular pattern (DAMP) molecules and cytokines that activate pro-inflammatory immune cell mediators. ==Discovery of pyroptosis== This type of inherently proinflammatory programmed cell death was named ‘pyroptosis’ in 2001 by Dr. Brad T.Cookson, an associate professor of microbiology and laboratory medicine of University of Washington.〔 〕 ''"Pyro"'' and'' "ptosis"'' are two Greek words, the first word refers to fire and the latter means falling. The apparent meaning of the combined word "pyroptosis" is therefore, "the falling of fire", which here refers to the process of pro-inflammatory chemical signals bursting out of a host cell. Pyroptosis has a distinct morphology and mechanism compared to other forms of cell death. However, this form of cell death is akin to necrosis.〔 〕 It was suggested that microbial-infection was the main evolutionary pressure for this pathway.〔 〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「pyroptosis」の詳細全文を読む スポンサード リンク
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