Dataset Information

Endocytic deficiency induced by ITSN-1s knockdown alters the Smad2/3-Erk1/2 signaling balance downstream of Alk5.

ABSTRACT: Recently, we demonstrated in cultured endothelial cells and in vivo that deficiency of an isoform of intersectin-1, ITSN-1s, impairs caveolae and clathrin-mediated endocytosis and functionally upregulates compensatory pathways and their morphological carriers (i.e. enlarged endocytic structures, membranous rings or tubules) that are normally underrepresented. We now show that these endocytic structures internalize the broadly expressed transforming growth factor ? receptor I (TGF?-RI or TGFBR1), also known as Alk5, leading to its ubiquitylation and degradation. Moreover, the apoptotic or activated vascular cells of the ITSN-1s-knockdown mice release Alk5-bearing microparticles to the systemic circulation. These interact with and transfer Alk5 to endocytosis-deficient endothelial cells, resulting in lung endothelial cell survival and phenotypic alteration towards proliferation through activation of Erk1 and Erk2 (also known as MAPK3 and MAPK1, respectively). We also show that non-productive assembly of the Alk5-Smad-SARA (Smad anchor for receptor activation, also known as ZFYVE9) signaling complex and preferential formation of the Alk5-mSos-Grb2 complex account for Erk1/2 activation downstream of Alk5 and proliferation of pulmonary endothelial cells. Taken together, our studies demonstrate a functional relationship between the intercellular transfer of Alk5 by microparticles and endothelial cell survival and proliferation, and define a novel molecular mechanism for TGF? and Alk5-dependent Erk1/2(MAPK) signaling that is significant for proliferative signaling and abnormal growth.

SUBMITTER: Bardita C

PROVIDER: S-EPMC4406123 | biostudies-literature | 2015 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Endocytic deficiency induced by ITSN-1s knockdown alters the Smad2/3-Erk1/2 signaling balance downstream of Alk5.

Bardita Cristina C Predescu Dan N DN Sha Fei F Patel Monal M Balaji Ganesh G Predescu Sanda A SA

Journal of cell science 20150226 8

Recently, we demonstrated in cultured endothelial cells and in vivo that deficiency of an isoform of intersectin-1, ITSN-1s, impairs caveolae and clathrin-mediated endocytosis and functionally upregulates compensatory pathways and their morphological carriers (i.e. enlarged endocytic structures, membranous rings or tubules) that are normally underrepresented. We now show that these endocytic structures internalize the broadly expressed transforming growth factor β receptor I (TGFβ-RI or TGFBR1), ...[more]

PMID: 25720380

Similar Datasets

Project description:Although mitochondrial activity is critical for angiogenesis, its mechanism is not entirely clear. Here, we investigate the angiogenic functions of three separate nuclear genes that encode for mitochondrial proteins, including mitochondrial transcriptional factor (TFAM), respiratory complex IV component (COX10), and a mitochondrial redox protein thioredoxin 2 (TRX2), which are responsible for distinct mitochondrial functions. We aim to investigate if mitochondrial activities regulate common endothelial cell (EC) signaling pathways during angiogenesis. The silencing of Tfam, Cox10, or Trx2 in an in vitro 3D sprouting assay attenuates EC sprouting, which correlated with reduced EC proliferation but not with ROS generation or EC apoptosis. Mice with an inducible deletion of Tfam, Cox10, or Trx2 exhibit retarded retinal vessel growth without penetration into the deep plexi at early ages (P5-P12). The three mutant mice develop arteriovenous malformations (AVM) with microaneurysm formation in the microvessels at advanced ages (P12-P30); the hypovasculature and microaneurysm phenotypes resemble that of aged human retinas and human primitive retinal vascular abnormalities such as Coats’ disease, Leber’s military aneurysms and familial exudative vitreoretinopathy. Single-cell RNA-seq analyses of retinal ECs suggest that the three mutant mice have common EC clusters with reduced gene expressions in anion transporters, actin organization, extracellular matrix, and angiogenesis. These EC clusters also have increased gene expressions in endothelial-mesenchymal transition and arterial markers, correlating with enhanced TGFbR signaling in Tfam, Cox10, or Trx2-deficient mice. Importantly, pharmacological blockade by TGFbR inhibitors attenuated retinal vessel growth retardation and AVM formation in all three mutant mice. Our study demonstrates that mitochondrial dysfunction induces TGF-b receptor-mediated arteriovenous malformations and microaneurysm formation in mouse retinas, and provide a novel model and therapeutic intervention for human primitive retinal vascular abnormalities, which are characterized by retinal vascular malformations and are associated with many pathological complications such as diabetes and hypertension that can result in vision loss.

Dataset Information

Endocytic deficiency induced by ITSN-1s knockdown alters the Smad2/3-Erk1/2 signaling balance downstream of Alk5.

Publications

Endocytic deficiency induced by ITSN-1s knockdown alters the Smad2/3-Erk1/2 signaling balance downstream of Alk5.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets