Abstract 19986: Cyclic Stretch-induced CRP3/MLP Sensitizes Vascular Smooth Muscle Cells to Apoptosis During Vein Remodeling in Response to Arterialization
Introduction: We have demonstrated stretch-induced up-regulation of cysteine- and glycine-rich protein 3/muscle LIM-domain protein (CRP3/MLP) rat and human saphenous veins in response to arterialization.
Hypothesis: We developed a KO rat to test the hypothesis that CRP3/MLP is a key modifier of vein remodeling during arterialization.
Methods/Results: Under basal conditions, we found no micro-macroscopic gross abnormalities in conduit arterial/vein vessels in KO rats. Upon arterialization of jugular vein for 28 days, CRP3 KO compared to WT rats showed a 3-fold increase of intima layer (Area 103 μm2 - CRP3 KO: 250.9 ± 80.0, WT: 79.7 ± 32.3) and inhibition of early apoptotic event (TUNEL positive cells - CRP3 KO: 0.4 ± 0.7, WT: 30.6 ± 6.8). To gain insight on the increased remodeling response, we investigated CRP3 role on apoptosis. Interestingly, ceramide-induced apoptosis was restricted to the presence of basal CRP3 expression. Aortic SMCs, with endogenous CRP3 expression, displayed increased apoptosis compared to cells from KO rats (% of dead cells - CTRL - CRP3 KO: 1.8 ± 0.3, WT: 8.3 ± 1.7; Ceramide 100μm- CRP3 KO: 12.4 ± 7.3, WT: 54.8 ± 8.3). Ceramide failed to induce apoptosis in the absence of CRP3 expression in both jugular vein SMC KO and WT under basal conditions. Upon stretch, WT vein SMC displayed increased CRP3 expression (CRP3/GAPDH gene expression -Static: 0; Stretched: 0.4 ± 0.05) that was accompanied by ceramide-induced apoptosis (% of dead cells - Static control: 0.5 ± 0.1; Static ceramide: 0.8 ± 0.1; Stretched control: 0.7 ± 0.6; Stretched ceramide: 11.4 ± 0.1). Similarly, ceramide-induced apoptosis decreased in stretched CRP3-KO jugular (% of dead cells - Static control: 0.4 ± 0.06; Static ceramide: 0.8 ± 0.07; Stretched control: 0.4 ± 0.2; Stretched ceramide: 0.9 ± 0.06). Western blot analysis showed that ceramide stretch-induced apoptosis in SMC is accompanied by decreased pFAK and pAKT, which may lead Bax to translocate to mitochondria, resulting in caspase 3 activation.
Conclusion: Taken together, we provide evidence that CRP3/MLP influences vein remodeling in response to arterialization by sensitizing cells to stretch-induced apoptosis.
Author Disclosures: L.C. Campos: None. A.S. Menegon: None. V. Barauna: None. P.R. Mautan: None. A.A. Miyakawa: None. J. Krieger: None.
- © 2014 by American Heart Association, Inc.