CCN1: a SASPy protein that plays multifaceted roles in fibrogenesis

The matricellular protein CCN1 is pro-senescent, and can be considered as a possible inducer of the senescence-associated secretory phenotype (SASP). Although the SASP facilitates healthy tissue repair when senescent cells are properly cleared, pathological fibrosis results when this clearance is defective. Similarly, CCN1 can have both anti-fibrotic and pro-fibrotic properties, depending on the context. Recent data indicate that although CCN1 has anti-fibrotic roles in normal tissue repair and the liver, it also has pro-fibrotic roles in lung, kidney, cardiac, skin and liver fibrosis/scarring. That CCN1 has context-dependent roles in fibrosis deserves consideration when developing anti-fibrotic drugs.