Nuclear factor of activated T cells and early growth response-1 cooperate to mediate tissue factor gene induction by vascular endothelial growth factor in endothelial cells

Abstract

Endothelial progenitor cells (EPCs) have been implicated in vascular repair and found to be functionally impaired in patients with diabetes. We evaluated the effects of the anti-diabetic drug pioglitazone on human EPC function and the involvement of PPAR-gamma and TGF-beta1. EPCs in culture were characterized at day 7 by the development of colony-forming units (CFUs) and flow cytometry assessment of differentiation marker (DiI-ac-LDL/lectin, KDR and CD31). Adhesion on fibronectin and fibrinogen in flow was analyzed as functional parameter. Treatment with pioglitazone for 72 hours increased the number of EPC-CFUs, DiI-ac-LDL(+)/lectin(+), CD31(+) and KDR(+) EPCs at 1 microM but not at 10 microM. Since pioglitazone did not significantly alter proliferation and apoptosis in cultured EPCs, the increase in EPC number was most likely attributable to augmented adhesion and differentiation. Indeed, pioglitazone increased EPC adhesion in flow at 1 microM, an effect prevented by PPAR-gamma and beta2-integrin blockade. In contrast, pioglitazone did not promote EPC adhesion at 10 microM; however, increased adhesion became evident by co-incubation with a blocking TGF-beta1 antibody. As determined by ELISA, pioglitazone induced a persistent increase in TGF-beta1 secretion only at 10 microM when a significantly elevated expression of endoglin, the accessory receptor for TGF-beta1, was also observed. Taken together, pioglitazone exerts biphasic effects on the function of isolated EPCs, causing a PPAR-gamma-dependent stimulation at 1 microM and a TGF-beta1-mediated suppression at 10 microM. These results may help to define optimal therapeutic doses of pioglitazone for improving endothelial dysfunction.

Loss of Extracellular Superoxide Dismutase Leads to Acute Lung Damage in the Presence of Ambient Air

“…FosB interacts with the DNA-binding complex AP1 and modulates nuclear gene transcription. 50 The transcription factor early growth response (Erg-1) has been shown to be involved in the tissue factor gene regulation, 51 and Etv5 is a member of the Ets transcription factor family. 44 Other cell signaling genes that are highly expressed in the SOD3 Ϫ/Ϫ lungs include the FGF receptor 3, which has been implicated in lymphatic vessel development 52 ; the Ras effector family member Rassf3, which can function as a tumor suppressor 53 ; and ARf3, a member of the small G-protein family that is involved in epithelial cell proliferation.…”

A Recurrent Activating PLCG1 Mutation in Cardiac Angiosarcomas Increases Apoptosis Resistance and Invasiveness of Endothelial Cells

“…Activated PLCg1 cleaves PIP2 to generate DAG and IP3 and DAG can activate the RAF-MEK-ERK pathway via protein kinase C and IP3 via Ca 2þ release Ca 2þ -dependent enzymes, such as the serine/threonine phosphatase calcineurin, which dephosphorylates nuclear factor of activated T cells (NFAT) in endothelial cells (20)(21)(22). Expression of the PLCg1-R707Q mutant in HUVECs and HEK293 cells caused stronger phosphorylation of c-RAF, MEK, and ERK1/2 than PLCg1-WT (Fig.…”

Advances in Regenerative Medicine

“…Originally discovered as a potent and rapid inducer of vascular permeability (Vascular Permeability Factor, VPF) (Senger et al, 1983), it was then found to have a modest mitogenic effect on mature endothelial cells (Keck et al, 1989;Leung et al, 1989;Plouet et al, 1989) and finally it was shown to be an important participant in the regulation of EPC kinetics (Asahara et al, 1999;Olsson et al, 2006). Specifically, VEGF is believed to promote the mobilization of EPCs from the BM into the circulation by a) stimulating BM EPC proliferation b) providing a chemoattractive gradient for EPC migration towards the site of injury and c) modulating the BM-blood barrier, by increasing its permeability and modifying the expression of adhesion molecules (Asahara et al, 1999 Schabbauer et al, 2007). This is a tyrosine kinase containing in its cytoplasmic domain 19 tyrosine residues which are in part phosphorylated upon activation by receptor ligands and function as specific docking sites for molecules that initiate cytoplasmic signaling cascades (Olsson et al, 2006;Schabbauer et al, 2007).…”