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Short answer
Pyroptosis is a lytic, inflammatory form of programmed cell death in which gasdermin proteins, usually gasdermin D (GSDMD) cut by inflammatory caspases, form pores in the plasma membrane. The cell swells and ruptures and releases mature IL-1β and IL-18, unlike apoptosis, which keeps the membrane intact. In the lab, no single assay separates the two: you need a combination of readouts.
Definition and scope
The meaning of pyroptosis, as used in current reviews, is a type of programmed necrosis triggered by detection of pathogens, first reported in the late 1990s and characterised by plasma membrane rupture and inflammatory signalling (Broz, Cell Research 2025). A second review describes it as “a form of programmed necrosis mediated by gasdermin proteins” (Frontiers in Immunology 2023). This page is a research-practice explainer for lab staff and researchers; it is general information, not medical advice.
How pyroptosis works
Canonical and noncanonical pathways
In the canonical pathway, sensors such as NLRs, AIM2 and pyrin assemble inflammasomes that activate caspase-1. In the noncanonical pathway, caspase-4 and caspase-5 (human) or caspase-11 (mouse) sense intracellular lipopolysaccharide (LPS) directly, without needing a sensor or the adaptor ASC.
Gasdermin pores and membrane rupture
Caspase-1, -4 and -11 cleave GSDMD after aspartate (D275 in the human protein). The released N-terminal fragment forms pores in the membrane (about 20 nm inner diameter in liposome studies), allowing ion flux and water influx and causing swelling. NINJ1 then drives the final plasma membrane rupture. Mature IL-1β and IL-18, but not their precursors, are released, and this release can occur independently of lysis, possibly through gasdermin pores.
Caspase-3 and caspase-7 can cleave GSDME to trigger pyroptosis, so a “caspase-3 means apoptosis” shortcut does not hold. The 2023 review also reports that caspase-3/7 can deactivate GSDMD by cleaving it at Asp87, which is one reason apoptotic stimuli can prevent pyroptosis.
How labs tell pyroptosis from apoptosis
The table below is an original synthesis of readouts named in Broz (2025); it is a reading aid, not a protocol.
| Readout | What it indicates | Caveat stated in the source |
|---|---|---|
| LDH release | Loss of membrane integrity; often used as a pyroptosis readout | Reflects lysis in general, so it does not identify the pathway on its own |
| Propidium iodide (PI) uptake | Pore formation in the membrane | Does not reliably reflect NINJ1-dependent lysis |
| Cleaved GSDMD (31 kDa N-terminal, 22 kDa C-terminal fragments) | Gasdermin D activation | Specific to GSDMD; other gasdermins need their own readouts |
| Mature IL-1β / IL-18 | Inflammatory cytokine processing and release | Release can occur independently of lysis |
| Phosphatidylserine exposure | Listed as a readout in the review | Interpret alongside membrane-integrity data |
| Gasdermin or upstream-caspase knockouts | Genetic confirmation that the death depends on that pathway | Requires a suitable cell model |
The practical consequence: pair a membrane-integrity assay with a pathway-specific marker, and do not read caspase-3 activity alone as proof of apoptosis. For apoptosis-side assays see Annexin V/PI apoptosis assay setup, cytotoxicity and how to interpret Western blot results (for cleaved-fragment bands). Cytokine readouts are commonly measured by ELISA; see direct ELISA assay.
Pyroptosis versus apoptosis versus necroptosis
What is the difference between pyroptosis and apoptosis?
Apoptosis preserves plasma membrane integrity (pyknosis, blebbing, apoptotic bodies), whereas pyroptosis ends in pore formation, swelling and membrane rupture with inflammatory cytokine release. The 2023 review notes that apoptotic stimuli can specifically prevent or even deactivate pyroptosis. For the apoptosis side, see what causes apoptosis.
What is the difference between pyroptosis and necroptosis?
Pyroptosis, necroptosis and ferroptosis are among the best-studied lytic cell death modalities, and they are hard to tell apart by morphology alone. This page does not rely on necroptosis detail; confirming which pathway is active needs pathway-specific readouts.
Where it matters for labs and clinics
Because membrane-integrity assays and caspase markers overlap across death modes, a cell-death assay panel should state which pathway-specific readout supports a “pyroptosis” label. Researchers should also note that, per Broz (2025), no selective gasdermin inhibitors are currently available; the 2023 review describes Ac-FLTD-CMK (an inflammatory caspase inhibitor) and necrosulfonamide (“direct but nonspecific”), and disulfiram and dimethyl fumarate, which modify Cys191 and carry off-target risk from covalent chemistry. In disease research, pyroptosis protects the host against bacterial infection, while persistent activation is linked to sepsis, COVID-19 and neurodegeneration, and it is described as a double-edged sword in tumour development.
Common misunderstandings
- “Caspase-3 activation means apoptosis.” Caspase-3/7 can cleave GSDME and drive pyroptosis.
- “PI-positive cells are pyroptotic.” PI uptake shows pore formation and does not reliably track NINJ1-dependent lysis.
- “Cytokine release requires cell lysis.” Mature IL-1β/IL-18 release can be independent of lysis.
FAQ
What is the meaning of pyroptosis?
It is inflammatory, gasdermin-mediated programmed cell death that ends in membrane rupture and release of IL-1β and IL-18.
Is pyroptosis bad?
Not inherently. It helps defend against bacterial infection, but persistent activation is linked to sepsis, COVID-19 and neurodegeneration, and in cancer its effect is context dependent: GSDMD-mediated pyroptosis inhibits gastric cancer growth yet promotes proliferation in bladder cancer, per the 2023 review.
What is the difference between pyroptosis and apoptosis?
Membrane intact (apoptosis) versus gasdermin pores and rupture (pyroptosis); see the comparison section above.
What is the difference between pyroptosis and necroptosis?
Both are lytic forms of cell death and are hard to tell apart by morphology alone, so a pathway-specific readout is needed to assign a label.
Sources
- Broz P. Pyroptosis: molecular mechanisms and roles in disease. Cell Research 2025. DOI 10.1038/s41422-025-01107-6. pmc.ncbi.nlm.nih.gov/articles/PMC12012027 (read 2026-11-07).
- Gasdermin D-mediated pyroptosis: mechanisms, diseases, and inhibitors. Frontiers in Immunology 2023. pmc.ncbi.nlm.nih.gov/articles/PMC10232970 (read 2026-11-07).
