Pyroptosis is a highly inflammatory form of lytic programmed cell death that occurs most frequently upon infection with intracellular pathogens and is likely to form part of the antimicrobial response. This process promotes the rapid clearance of various bacterial, viral, fungal and protozoan infections by removing intracellular replication niches and enhancing the host's defensive responses. Pyroptosis can take place in immune cells and is also reported to occur in keratinocytes and some epithelial cells.
The process is initiated by formation of a large supramolecular complex termed the inflammasome (also known as a pyroptosome) upon intracellular danger signals. The inflammasome activates a different set of caspases as compared to apoptosis, for example, caspase-1/4/5 in humans and caspase-11 in mice. These caspases contribute to the maturation and activation of the pro-inflammatory cytokines IL-1β and IL-18, as well as the pore-forming protein gasdermin D. Formation of pores causes cell membrane rupture and release of cytokines, as well as various damage-associated molecular pattern (DAMP) molecules such as HMGB-1, ATP and DNA, out of the cell. These molecules recruit more immune cells and further perpetuate the inflammatory cascade in the tissue.
However, in pathogenic chronic diseases, the inflammatory response does not eradicate the primary stimulus. A chronic form of inflammation ensues that ultimately contributes to tissue damage. Pyroptosis is associated with diseases including autoinflammatory, metabolic, and cardiovascular diseases, as well as cancer and neurodegeneration. Some examples of pyroptosis include the cell death induced in Salmonella-infected macrophages and abortively HIV-infected T helper cells.
This type of inherently pro-inflammatory programmed cell death was named pyroptosis in 2001 by Molly Brennan and Dr. Brad T. Cookson, an associate professor of microbiology and laboratory medicine at the University of Washington. The Greek pyro refers to fire and ptosis means falling.
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.
Inflammasomes are cytosolic multiprotein oligomers of the innate immune system responsible for the activation of inflammatory responses. Activation and assembly of the inflammasome promotes proteolytic cleavage, maturation and secretion of pro-inflammatory cytokines interleukin 1β (IL-1β) and interleukin 18 (IL-18), as well as cleavage of gasdermin D. The N-terminal fragment resulting from this cleavage induces a pro-inflammatory form of programmed cell death distinct from apoptosis, referred to as pyroptosis, and is responsible for secretion of the mature cytokines, presumably through the formation of pores in the plasma membrane.
The Interleukin-1 family (IL-1 family) is a group of 11 cytokines that plays a central role in the regulation of immune and inflammatory responses to infections or sterile insults. Discovery of these cytokines began with studies on the pathogenesis of fever. The studies were performed by Eli Menkin and Paul Beeson in 1943–1948 on the fever-producing properties of proteins released from rabbit peritoneal exudate cells. These studies were followed by contributions of several investigators, who were primarily interested in the link between fever and infection/inflammation.
Caspases (cysteine-aspartic proteases, cysteine aspartases or cysteine-dependent aspartate-directed proteases) are a family of protease enzymes playing essential roles in programmed cell death. They are named caspases due to their specific cysteine protease activity – a cysteine in its active site nucleophilically attacks and cleaves a target protein only after an aspartic acid residue. As of 2009, there are 12 confirmed caspases in humans and 10 in mice, carrying out a variety of cellular functions.
Mycobacterium Tuberculosis is a highly effective pathogen infecting nearly a third of the world's population. An M. tuberculosis infection starts when droplets containing bacteria enter an individual's lungs. The first host cells to contact the bacteria ar ...
EPFL2024
Inflammation stands as a dynamic and intricate biological process, promoting vital defence mechanisms against harmful stimuli, including infections and injuries, to drive pathogen clearance and healing. On one hand, these responses can manifest acutely and ...
EPFL2024
,
The NLRP3 inflammasome is a central component of the innate immune system. Its activation leads to for-mation of the ASC speck, a supramolecular assembly of the inflammasome adaptor protein ASC. Different models, based on ASC overexpression, have been prop ...