Research ArticleImmunology

Dichotomous roles for externalized cardiolipin in extracellular signaling: Promotion of phagocytosis and attenuation of innate immunity

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Science Signaling  22 Sep 2015:
Vol. 8, Issue 395, pp. ra95
DOI: 10.1126/scisignal.aaa6179

Mitochondrial phospholipid modulates immunity

The phospholipid cardiolipin normally resides in the inner mitochondrial membrane; however, cardiolipin becomes exposed on the outer membrane of damaged mitochondria and acts as an “eat me” signal to promote mitochondrial elimination by mitophagy. Balasubramanian et al. showed that cardiolipin presented on vesicular, mitochondrial, or bacterial membranes to macrophages functioned as an eat me signal to the macrophages, through a process dependent on the macrophage scavenger receptor CD36. Independently of phagocytosis, cardiolipin also inhibited macrophage cytokine production in response to the bacterial compound lipopolysaccharide. Together, these results suggest that cardiolipin both promotes the phagocytosis of cellular debris and pathogens and dampens the innate immune response.

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