ATF6? regulates morphological changes associated with senescence in human fibroblasts.

ABSTRACT: Cellular senescence is known as an anti-tumor barrier and is characterized by a number of determinants including cell cycle arrest, senescence associated ?-galactosidase activity and secretion of pro-inflammatory mediators. Senescent cells are also subjected to enlargement, cytoskeleton-mediated shape changes and organelle alterations. However, the underlying molecular mechanisms responsible for these last changes remain still uncharacterized. Herein, we have identified the Unfolded Protein Response (UPR) as a player controlling some morphological aspects of the senescent phenotype. We show that senescent fibroblasts exhibit ER expansion and mild UPR activation, but conserve an ER stress adaptive capacity similar to that of exponentially growing cells. By genetically invalidating the three UPR sensors in senescent fibroblasts, we demonstrated that ATF6? signaling dictates senescence-associated cell shape modifications. We also show that ER expansion and increased secretion of the pro-inflammatory mediator IL6 were partly reversed by silencing ATF6? in senescent cells. Moreover, ATF6? drives the increase of senescence associated-?-galactosidase activity. Collectively, these findings unveil a novel and central role for ATF6? in the establishment of morphological features of senescence in normal human primary fibroblasts.

SUBMITTER: Druelle C 

PROVIDER: S-EPMC5356513 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature