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DEPTOR: A Novel Cell‐Intrinsic Molecule That Plays A Critical Role In The Regulation Of Endothelial Activation, Proinflammatory And Angiogenic Responses
Author(s) -
Bruneau Sarah,
Woda Craig Bryan,
Briscoe David Michael
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.57.2
Subject(s) - microbiology and biotechnology , pi3k/akt/mtor pathway , angiogenesis , chemokine , proinflammatory cytokine , cancer research , mtorc1 , gene knockdown , biology , signal transduction , inflammation , chemistry , immunology , cell culture , genetics
Cytokine‐mediated activation of endothelial cells (EC) is characteristic of immune inflammation, and therapeutics that inhibit EC activation have broad implications for the treatment of chronic diseases. Here, by qPCR and Western blot analyses, we find that DEPTOR, an intracellular inhibitor of mTOR signaling, is expressed in vascular EC. Using a siRNA knockdown approach and phosphokinase arrays, we found that DEPTOR functions to inhibit the mTOR, ERK1/2 and STAT1 signaling pathways in EC. Moreover, using pharmacological inhibitors of mTOR (Rapamycin, Torin1) and ERK1/2 (U0126), we found that DEPTOR regulates each of these pathways through independent mechanisms. Importantly, we also found that knockdown of DEPTOR in EC results in marked activation responses, including up to an ~1000 fold increase in the mRNA expression of T cell chemokines (CXCL9, CXCL10, CXCL11, CX3CL1 and CCL5) and adhesion molecules (VCAM‐1 and ICAM‐1). Functionally, we also found that DEPTOR siRNA transfected EC, a) bind increased numbers of PBMC and CD3+ T cells (P<0.005) in adhesion assays and b) have increased migration and angiogenic responses (P<0.01) in the wound healing and spheroid sprouting assays. Collectively, these findings identify DEPTOR as a novel regulatory molecule in EC, and suggest that its relative level of expression is of great importance in EC‐dependent mechanisms of inflammation and in immune angiogenesis.