Celledød Flashcards by Lars Anda Berg

Hva er forskjellen mellom apoptose og nekrose?

Hva er hhv.:

Autofagi
Nekroptose
Pyroptose

https://www.nature.com/articles/nrm2970

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Hva er forskjellene mellom nekrose og apoptose?

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Hva er apoptose?

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Hva er apoptose nødvendig for?

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Hvordan foregår fagocytose av apoptotiske celler?

B.n.t.v:

Different steps involved in efficient apoptotic cell clearance. The find-me signals (such as low levels of nucleotides ATP and UTP, fractalkine, lysophosphatidylcholine, or sphingosine 1-phosphate) released by apoptotic cells help attract motile phagocytes to the proximity of the cell undergoing apoptosis. The phagocytes then use engulfment receptors on their surface to engage eat-me signals on apoptotic cells. For clarity, only the PtdSer on the apoptotic cells engaged by cognate receptors is depicted. Engagement of the engulfment receptors (linked to PtdSer recognition) has been shown to stimulate release of antiinflammatory cytokines such as TGF-β, IL-10, and prostaglandin E2 (PGE2). The intracellular signaling induced within the phagocyte by the ligand–receptor interactions leads to cytoskeletal rearrangements and internalization of the dying cell. The phagocyte processes the engulfed corpse through a series of steps, and proper digestion seems to be important for continued uptake of other dying cells by phagocytes.

B.n.t.h:

A possible engulfment synapse during apoptotic cell clearance. In a speculative model, an engulfment synapse may help phagocyte binding to and subsequent internalization of apoptotic target cells. There appears to be some clear similarities between T cell–APC recognition and phagocyte–apoptotic cell interactions (see text for more details). However, whereas the T cell–APC interaction is anchored by MHC+peptide interaction with the TCR, the PtdSer exposed on apoptotic cells perhaps may be more homogeneous (except for modifications such as oxidation, etc.), and is likely recognized by multiple PtdSer recognition receptors on the phagocyte. How the PtdSer is displayed on the apoptotic cells and how the different engulfment receptors are arranged on the phagocyte are not yet defined. One could speculate that a second signal analogous to B7 (ligand X) on the apoptotic cell may engage a co-stimulatory receptor analogous to CD28 (receptor X) on the phagocyte, thereby providing specificity, overcoming don’t-eat-me signals, lowering the threshold for phagocyte priming, and/or altering membrane curvature.