D-glucose stimulation of L-arginine transport and nitric oxide synthesis results from activation of mitogen-activated protein kinases p42/44 and Smad2 requiring functional type II TGF-beta receptors in human umbilical vein endothelium

J Cell Physiol. 2007 Sep;212(3):626-32. doi: 10.1002/jcp.21057.

Abstract

Elevated extracellular D-glucose increases transforming growth factor beta1 (TGF-beta1) release from human umbilical vein endothelium (HUVEC). TGF-beta1, via TGF-beta receptors I (TbetaRI) and TbetaRII, activates Smad2 and mitogen-activated protein kinases p44 and p42 (p42/44(mapk)). We studied whether D-glucose-stimulation of L-arginine transport and nitric oxide synthesis involves TGF-beta1 in primary cultures of HUVEC. TGF-beta1 release was higher ( approximately 1.6-fold) in 25 mM (high) compared with 5 mM (normal) D-glucose. TGF-beta1 increases L-arginine transport (half maximal effect approximately 1.6 ng/ml) in normal D-glucose, but did not alter high D-glucose-increased L-arginine transport. TGF-beta1 and high D-glucose increased hCAT-1 mRNA expression ( approximately 8-fold) and maximal transport velocity (V(max)), L-[(3)H]citrulline formation from L-[(3)H]arginine (index of NO synthesis) and endothelial NO synthase (eNOS) protein abundance, but did not alter eNOS phosphorylation. TGF-beta1 and high D-glucose increased p42/44(mapk) and Smad2 phosphorylation, an effect blocked by PD-98059 (MEK1/2 inhibitor). However, TGF-beta1 and high D-glucose were ineffective in cells expressing a truncated, negative dominant TbetaRII. High D-glucose increases L-arginine transport and eNOS expression following TbetaRII activation by TGF-beta1 involving p42/44(mapk) and Smad2 in HUVEC. Thus, TGF-beta1 could play a crucial role under conditions of hyperglycemia, such as gestational diabetes mellitus, which is associated with fetal endothelial dysfunction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alanine / metabolism*
  • Autocrine Communication
  • Biological Transport
  • Cationic Amino Acid Transporter 1 / biosynthesis
  • Cationic Amino Acid Transporter 1 / genetics
  • Cells, Cultured
  • Citrulline / metabolism
  • Endothelial Cells / drug effects
  • Endothelial Cells / enzymology
  • Endothelial Cells / metabolism*
  • Enzyme Activation
  • Enzyme Induction
  • Flavonoids / pharmacology
  • Glucose / metabolism*
  • Humans
  • Kinetics
  • Mitogen-Activated Protein Kinase 1 / antagonists & inhibitors
  • Mitogen-Activated Protein Kinase 1 / metabolism*
  • Mitogen-Activated Protein Kinase 3 / antagonists & inhibitors
  • Mitogen-Activated Protein Kinase 3 / metabolism*
  • Mutation
  • Nitric Oxide / biosynthesis*
  • Nitric Oxide Synthase Type III / biosynthesis
  • Nitric Oxide Synthase Type III / genetics
  • Phosphorylation
  • Protein Kinase Inhibitors / pharmacology
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism*
  • RNA, Messenger / biosynthesis
  • Receptor, Transforming Growth Factor-beta Type II
  • Receptors, Transforming Growth Factor beta / genetics
  • Receptors, Transforming Growth Factor beta / metabolism*
  • Signal Transduction
  • Smad2 Protein / metabolism*
  • Transduction, Genetic
  • Transforming Growth Factor beta1 / metabolism*

Substances

  • Cationic Amino Acid Transporter 1
  • Flavonoids
  • Protein Kinase Inhibitors
  • RNA, Messenger
  • Receptors, Transforming Growth Factor beta
  • SLC7A1 protein, human
  • SMAD2 protein, human
  • Smad2 Protein
  • Transforming Growth Factor beta1
  • Citrulline
  • Nitric Oxide
  • NOS3 protein, human
  • Nitric Oxide Synthase Type III
  • Protein Serine-Threonine Kinases
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • Receptor, Transforming Growth Factor-beta Type II
  • Glucose
  • Alanine
  • 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one