Caveolae control the anti‐inflammatory phenotype of senescent endothelial cells

EE Powter, PR Coleman, MH Tran, AJ Lay… - Aging cell, 2015 - Wiley Online Library
EE Powter, PR Coleman, MH Tran, AJ Lay, P Bertolino, RG Parton, MA Vadas, JR Gamble
Aging cell, 2015Wiley Online Library
Senescent endothelial cells (EC) have been identified in cardiovascular disease, in
angiogenic tumour associated vessels and in aged individuals. We have previously
identified a novel anti‐inflammatory senescent phenotype of EC. We show here that
caveolae are critical in the induction of this anti‐inflammatory senescent state. Senescent
EC induced by either the overexpression of ARHGAP18/SENEX or by H2O2 showed
significantly increased numbers of caveolae and associated proteins Caveolin‐1, cavin‐1 …
Summary
Senescent endothelial cells (EC) have been identified in cardiovascular disease, in angiogenic tumour associated vessels and in aged individuals. We have previously identified a novel anti‐inflammatory senescent phenotype of EC. We show here that caveolae are critical in the induction of this anti‐inflammatory senescent state. Senescent EC induced by either the overexpression of ARHGAP18/SENEX or by H2O2 showed significantly increased numbers of caveolae and associated proteins Caveolin‐1, cavin‐1 and cavin‐2. Depletion of these proteins by RNA interference decreased senescence induced by ARHGAP18 and by H2O2. ARHGAP18 overexpression induced a predominantly anti‐inflammatory senescent population and depletion of the caveolae‐associated proteins resulted in the preferential reduction in this senescent population as measured by neutrophil adhesion and adhesion protein expression after TNFα treatment. In confirmation, EC isolated from the aortas of CAV‐1−/− mice failed to induce this anti‐inflammatory senescent cell population upon expression of ARHGAP18, whereas EC from wild‐type mice showed a significant increase. NF‐κB is one of the major transcription factors mediating the induction of E‐selectin and VCAM‐1 expression, adhesion molecules responsible for leucocyte attachment to EC. TNFα‐induced activation of NF‐κB was suppressed in ARHGAP18‐induced senescent EC, and this inhibition was reversed by Caveolin‐1 knock‐down. Thus, out results demonstrate that an increase in caveolae and its component proteins in senescent ECs is associated with inhibition of the NF‐kB signalling pathway and promotion of the anti‐inflammatory senescent pathway.
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