Ca2+ source-dependent transcription of CRE-containing genes in vascular smooth muscle.
Altered Ca2+ handling has immediate physiological and long-term genomic effects on vascular smooth muscle function. Previously we showed that Ca2+ entry through voltage-dependent Ca2+ channels (VDCCs) or store-operated Ca2+ channels (SOCCs) results in phosphorylation of the Ca2+/cAMP response element (CRE)-binding protein in cerebral arteries. Here, oligonucleotide array analysis was used to determine gene transcription profiles resulting from these two Ca2+ entry pathways in human cerebrovascular smooth muscle cell cultures. Results were confirmed and expanded using quantitative RT-PCR, Western blot, and immunofluorescence. A distinct, yet overlapping, set of CRE-regulated genes was induced by VDCC activation using K+ membrane depolarization vs. SOCC activation by thapsigargin (TG). Membrane depolarization selectively induced a sustained increase in early growth response-1 (Egr-1) mRNA and protein, which were inhibited by the VDCC blocker nimodipine and the SOCC inhibitor 2-aminoethoxydiphenylborate (2-APB). TG selectively induced a sustained increase in MAPK phosphatase-1 (MKP-1) mRNA and protein, and these effects were decreased by 2-APB, but not by nimodipine. The physiological agonist ANG II also stimulated expression of Egr-1 and MKP-1. Coadministration of 2-APB prevented expression of Egr-1 and MKP-1, whereas nimodipine blocked only Egr-1 expression. TG and ANG II induced phosphorylation of ERK, which was sensitive to 2-APB and was selectively required for CRE-binding protein phosphorylation. Our findings thus indicate that Ca2+ entry through VDCCs and store-operated Ca2+ entry can differentially regulate CRE-containing genes in vascular smooth muscle and also imply that agonist-induced signals involved in modulation of gene transcription can be controlled by multiple sources of Ca2+.
Pulver-Kaste
Renee A
RA
Department of Pharmacology, Division of Neurological Surgery, University of Vermont, Burlington, VT 05405, USA.
Barlow
Christy A
CA
Bond
Jeffery
J
Watson
Anjanette
A
Penar
Paul L
PL
Tranmer
Bruce
B
Lounsbury
Karen M
KM
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020746:Calcium Channels, L-Type / Q000502:physiology*; D020013:Calcium Signaling / Q000502:physiology*; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000502:physiology*; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D032389:Myocytes, Smooth Muscle / Q000502:physiology*; D051381:Rats; D014158:Transcription, Genetic / Q000502:physiology*
D020746:Calcium Channels, L-Type; D017362:Cyclic AMP Response Element-Binding Protein; D002118:Calcium