Sphingosine-1-phosphate and endothelin-1 induce the expression of rgs16 protein in cardiac myocytes by transcriptional activation of the rgs16 gene.
The expression of the negative Regulator of G protein signaling 16 (RGS16) is rapidly induced in cardiomyocytes by various stimuli. To identify the promoter of the mouse RGS16 gene, a 1.8-kb deoxyribonucleic acid fragment 5' of the RGS16-coding region was subcloned into a firefly-luciferase reporter vector and four overlapping fragments were analyzed. The luciferase production was quantified in neonatal rat cardiac myocytes (NRCM). A 0.6-kb fragment that induced a tenfold increase in luciferase activity contained the minimal promoter sequence. Its activity was twofold stimulated by fetal calf serum, endothelin-1 (ET-1), and sphingosine 1-phosphate (S1P), which stimuli also elevated the level of RGS16 protein. Stimulation of NRCM with ET-1 induced activation of the monomeric GTPases RhoA and Rac1, whereas S1P and the selective S1P1 receptor agonist SEW2871 only induced a pronounced activation of Rac1. In accordance, the treatment with the Rho-, Rac-, and Cdc42-inactivating Clostridium difficile Toxin B (TcdB) 10463 inhibited ET-1 and S1P-induced transcriptional activation. The ET-1-induced activation was insensitive to pertussis toxin but selectively suppressed by the RhoA-C-specific C2I-C3 ADP-ribosyl transferase and the ET(B) receptor antagonist BQ788. The S1P-induced activation was specifically inhibited by pertussis toxin and the Rac-inactivating TcdB 1470. All stimulated transcriptional activity was abolished by the negative transcription factor Yin Yang 1 (YY1), which binds to a consensus sequence within the minimal promoter. Taken together, our data show that most likely ET(B)- and S1P1-receptors induce RGS16 protein expression in cardiac myocytes by increasing the transcriptional activity of the rgs16 gene. This activation is mediated by heterotrimeric G proteins, Rho GTPases, and is under negative control of the transcription factor YY1.
Universitäres Herzzentrum, Kardiologie, Universitätsklinikum Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany.
Sabine
S
Stuebe
Thomas
T
Wieland
Elisabeth
E
Kraemer
Alexandra v
Av
Stritzky
Diana
D
Schroeder
Sünje
S
Seekamp
Andreas
A
Vogt
Ching-Kang
CK
Chen
Monica
M
Patten
D000818:Animals; D000831:Animals, Newborn; D001426:Bacterial Proteins / Q000494:pharmacology; D001427:Bacterial Toxins / Q000494:pharmacology; D002417:Cattle; D002478:Cells, Cultured; D019332:Endothelin-1 / Q000502:physiology*; D005312:Fetal Blood / Q000378:metabolism; D005786:Gene Expression Regulation; D008156:Luciferases / Q000378:metabolism; D008246:Lysophospholipids / Q000502:physiology*; D051379:Mice; D032383:Myocytes, Cardiac; D037342:Pertussis Toxin / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D020710:RGS Proteins / Q000378:metabolism*; D051381:Rats; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000502:physiology; D014158:Transcription, Genetic; D050986:YY1 Transcription Factor / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D019332:Endothelin-1; D008246:Lysophospholipids; D020710:RGS Proteins; C107413:RGS16 protein; D050986:YY1 Transcription Factor; C031815:toxB protein, Clostridium difficile; C060506:sphingosine 1-phosphate; D008156:Luciferases; D037342:Pertussis Toxin; D020830:rac1 GTP-Binding Protein; D020742:rhoA GTP-Binding Protein; D013110:Sphingosine