Calcium and the replication of human vascular smooth muscle cells: studies on the activation and translocation of extracellular signal regulated kinase (ERK) and cyclin D1 expression

Eur J Pharmacol. 2005 Feb 10;509(1):21-30. doi: 10.1016/j.ejphar.2004.12.036.

Abstract

Since the precise role of sarcoplasmic reticular Ca2+ in mediating vascular smooth muscle cells (VSMC) proliferation is unknown, the effect of pre-incubation with thapsigargin on extracellular signal regulated kinase (ERK) activation, the translocation of activated of ERK 1/2 to the nucleus, cyclin D1 expression, the onset of S phase and cytosolic Ca2+ levels were studied. Human saphenous vein VSMCs (hVSMC) were incubated with 10 nM thapsigargin for 24 h followed by stimulation with fetal calf serum and the activation of ERK1/2 and cyclin D1 assessed by western blotting, the intracellular distribution of ERK1/2 using indirect immunofluorescence, the onset of S-phase with the incorporation of bromodeoxyuridine and sarcoplasmic reticular Ca2+ status using FURA-2. Thapsigargin had a marginal effect on ERK1/2 activation only at 5 min and 10 min after stimulation with fetal calf serum. In contrast, the rapid translocation of ERK1/2 to the nucleus was completely blocked by thapsigargin. S phase was delayed by 8 h by thapsigargin which co-incided with the recovery of cytosolic Ca2+ levels and cyclin D1 expression. It is concluded that the inhibitory effect of thapsigargin (depletion of Ca2+ pools) on hVSMC replication is mediated through the inhibition of translocation of activated ERK1/2 to the nucleus and not to the phosphorylation of ERK, per se, which in turn prevents cyclin D1 expression and thus progression of the cell cycle.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcimycin / pharmacology
  • Calcium / chemistry
  • Calcium / metabolism*
  • Calcium Signaling / drug effects
  • Calcium Signaling / physiology
  • Cattle
  • Cell Division / drug effects
  • Cell Division / physiology
  • Cell Nucleus / drug effects
  • Cell Nucleus / physiology
  • Cyclin D1 / chemistry
  • Cyclin D1 / drug effects
  • Cyclin D1 / genetics*
  • Cytosol / metabolism
  • Egtazic Acid / analogs & derivatives
  • Egtazic Acid / pharmacology
  • Enzyme Activation / drug effects
  • Enzyme Activation / physiology*
  • Extracellular Signal-Regulated MAP Kinases / drug effects
  • Extracellular Signal-Regulated MAP Kinases / physiology*
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / genetics
  • Humans
  • Ionomycin / pharmacology
  • Mitogen-Activated Protein Kinase 3 / genetics*
  • Muscle, Smooth, Vascular / drug effects
  • Muscle, Smooth, Vascular / pathology
  • Muscle, Smooth, Vascular / physiology*
  • S Phase / drug effects
  • S Phase / physiology
  • Saphenous Vein / drug effects
  • Saphenous Vein / pathology
  • Saphenous Vein / physiology
  • Serum Albumin, Bovine / pharmacology
  • Thapsigargin / pharmacology
  • Translocation, Genetic

Substances

  • Cyclin D1
  • 1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester
  • Serum Albumin, Bovine
  • Calcimycin
  • Egtazic Acid
  • Ionomycin
  • Thapsigargin
  • Extracellular Signal-Regulated MAP Kinases
  • Mitogen-Activated Protein Kinase 3
  • Calcium