In vivo knockdown of intersectin-1s alters endothelial cell phenotype and causes microvascular remodeling in the mouse lungsReportar como inadecuado

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, Volume 18, Issue1, pp 5776

First Online: 07 October 2012DOI: 10.1007-s10495-012-0762-x

Cite this article as: Bardita, C., Predescu, D., Justice, M.J. et al. Apoptosis 2013 18: 57. doi:10.1007-s10495-012-0762-x


Intersectin-1s ITSN-1s is a general endocytic protein involved in regulating lung vascular permeability and endothelial cells ECs survival, via MEK-Erk1-2 signaling. To investigate the in vivo effects of ITSN-1s deficiency and the resulting ECs apoptosis on pulmonary vasculature and lung homeostasis, we used an ITSN-1s knocked-down KDITSN mouse generated by repeated delivery of a specific siRNA targeting ITSN-1 gene siRNAITSN. Biochemical and histological analyses as well as electron microscopy EM revealed that acute KDITSN 3-days 3d post-siRNAITSN treatment inhibited Erk1-2 pro-survival signaling, causing significant ECs apoptosis and lung injury; at 10d of KDITSN, caspase-3 activation was at peak, terminal deoxynucleotidyl transferase dUTP nick-end labeling TUNEL-positive ECs showed 3.4-fold increase, the mean linear intercept MLI showed 48% augment and pulmonary microvessel density as revealed by aquaporin-1 staining AQP-1 decreased by 30%, all compared to controls; pulmonary function was altered. Concomitantly, expression of several growth factors known to activate Erk1-2 and suppress Bad pro-apoptotic activity increased. KDITSN altered Smads activity, downstream of the transforming growth factor beta-receptor-1 TR1, as shown by subcellular fractionation and immunoblot analyses. Moreover, 24d post-siRNAITSN, surviving ECs became hyper-proliferative and apoptotic-resistant against ITSN-1s deficiency, as demonstrated by EM imaging, 5-bromo-deoxyuridine BrdU incorporation and Bad-Ser phosphorylation, respectively, leading to increased microvessel density and repair of the injured lungs, as well as matrix deposition. In sum, ECs endocytic dysfunction and apoptotic death caused by KDITSN contribute to the initial lung injury and microvascular loss, followed by endothelial phenotypic changes and microvascular remodeling in the remaining murine pulmonary microvascular bed.

KeywordsApoptosisEndothelial cellsMicrovascular remodelingPhenotypic changessiRNAElectronic supplementary materialThe online version of this article doi:10.1007-s10495-012-0762-x contains supplementary material, which is available to authorized users.

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Autor: CristinaBardita - DanPredescu - MatthewJ.Justice - IrinaPetrache - SandaPredescu


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