Identification of a zinc finger homoeodomain enhancer protein after AT(2) receptor stimulation by differential mRNA display.
Using differential mRNA display, we isolated differentially expressed genes after stimulation of angiotensin II (Ang II) type 2 (AT(2)) receptors in PC12w cells. Among the polymerase chain reaction products isolated, we identified Zfhep, a zinc finger homoeodomain enhancer-binding protein and the angiotensin AT(2) receptor itself, both implicated in developmental processes. In the presence of epidermal growth factor (EGF) a concordant expression pattern of Zfhep and AT(2) mRNA was observed with marked downregulation 6 hours after stimulation with EGF+Ang II. In quiescent PC12w cells, Zfhep mRNA was time-dependently induced by Ang II (10(-7) mol/L) up to 3 hours, an effect that was blocked by the selective AT(2) antagonist PD123177 (10(-6) mol/L). We extended our studies on Zfhep mRNA expression to cells of vascular origin (coronary endothelial cells [CECs]), that express AT(1) and AT(2) receptors, and that respond differently to Ang II dependent on which receptor subtype is stimulated. In CECs, Zfhep mRNA expression was induced up to 3 hours after AT(2) stimulation. Interestingly, this Zfhep induction was observed only when the AT(1) receptor was blocked by using the selective AT(1) receptor antagonist, losartan (10(-5) mol/L), suggesting a negative-regulatory influence of AT(1) receptors on AT(2)-induced Zfhep mRNA induction. In conclusion, Zfhep not only represents a suitable marker for AT(2) receptor activation, but it may also link AT(2) signaling and downstream events involved in the proposed function of the AT(2) receptor in development and regeneration.
Stoll
Monika
M
Department of Physiology, Medical College of Wisconsin, Milwaukee, USA. stoll@pharmakologie.uni-kiel.de
Hahn
Alfred W A
AW
Jonas
Uwe
U
Zhao
Yi
Y
Schieffer
Bernhard
B
Fischer
Jens W
JW
Unger
Thomas
T
D057911:Angiotensin Receptor Antagonists; D000818:Animals; D019439:Chromaffin Cells / Q000737:chemistry; D002999:Clone Cells; D003331:Coronary Vessels / Q000166:cytology; D004730:Endothelium, Vascular / Q000166:cytology; D020869:Gene Expression Profiling; D018398:Homeodomain Proteins / Q000302:isolation & purification*; D019808:Losartan / Q000494:pharmacology; D008297:Male; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D017208:Rats, Wistar; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin / Q000378:metabolism*; D014157:Transcription Factors / Q000302:isolation & purification*; D000071799:Zinc Finger E-box-Binding Homeobox 1; D016335:Zinc Fingers / Q000235:genetics
D057911:Angiotensin Receptor Antagonists; D018398:Homeodomain Proteins; D012333:RNA, Messenger; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin; D014157:Transcription Factors; C000630720:ZEB1 protein, rat; D000071799:Zinc Finger E-box-Binding Homeobox 1; D019808:Losartan