Src is required for mechanical stretch-induced cardiomyocyte hypertrophy through angiotensin II type 1 receptor-dependent β-arrestin2 pathways.
Angiotensin II (AngII) type 1 receptor (AT1-R) can be activated by mechanical stress (MS) without the involvement of AngII during the development of cardiomyocyte hypertrophy, in which G protein-independent pathways are critically involved. Although β-arrestin2-biased signaling has been speculated, little is known about how AT1-R/β-arrestin2 leads to ERK1/2 activation. Here, we present a novel mechanism by which Src kinase mediates AT1-R/β-arrestin2-dependent ERK1/2 phosphorylation in response to MS. Differing from stimulation by AngII, MS-triggered ERK1/2 phosphorylation is neither suppressed by overexpression of RGS4 (the negative regulator of the G-protein coupling signal) nor by inhibition of Gαq downstream protein kinase C (PKC) with GF109203X. The release of inositol 1,4,5-triphosphate (IP3) is increased by AngII but not by MS. These results collectively suggest that MS-induced ERK1/2 activation through AT1-R might be independent of G-protein coupling. Moreover, either knockdown of β-arrestin2 or overexpression of a dominant negative mutant of β-arrestin2 prevents MS-induced activation of ERK1/2. We further identifies a relationship between Src, a non-receptor tyrosine kinase and β-arrestin2 using analyses of co-immunoprecipitation and immunofluorescence after MS stimulation. Furthermore, MS-, but not AngII-induced ERK1/2 phosphorylation is attenuated by Src inhibition, which also significantly improves pressure overload-induced cardiac hypertrophy and dysfunction in mice lacking AngII. Finally, MS-induced Src activation and hypertrophic response are abolished by candesartan but not by valsartan whereas AngII-induced responses can be abrogated by both blockers. Our results suggest that Src plays a critical role in MS-induced cardiomyocyte hypertrophy through β-arrestin2-associated angiotensin II type 1 receptor signaling.
Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, China; Institutes of Biomedical Science, Fudan University, Shanghai, China.
Shijun
S
Wang
Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, China; Institutes of Biomedical Science, Fudan University, Shanghai, China.
Hui
H
Gong
Institutes of Biomedical Science, Fudan University, Shanghai, China.
Guoliang
G
Jiang
Institutes of Biomedical Science, Fudan University, Shanghai, China.
Yong
Y
Ye
Institutes of Biomedical Science, Fudan University, Shanghai, China.
Jian
J
Wu
Institutes of Biomedical Science, Fudan University, Shanghai, China.
Jieyun
J
You
Institutes of Biomedical Science, Fudan University, Shanghai, China.
Guoping
G
Zhang
Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, China; Institutes of Biomedical Science, Fudan University, Shanghai, China.
Aijun
A
Sun
Department of Cardiovascular Medicine, the University of Tokyo Graduate School of Medicine, Tokyo, Japan.
Issei
I
Komuro
Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, China; Institutes of Biomedical Science, Fudan University, Shanghai, China.
Junbo
J
Ge
Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, China; Institutes of Biomedical Science, Fudan University, Shanghai, China.
Yunzeng
Y
Zou
D000808:Angiotensinogen / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D019390:Arrestins / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D006332:Cardiomegaly / Q000378:metabolism / Q000473:pathology*; D002478:Cells, Cultured; D004452:Echocardiography; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000473:pathology*; D010766:Phosphorylation; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D044140:Receptor, Angiotensin, Type 1 / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013314:Stress, Mechanical; D000071557:beta-Arrestins; D019061:src-Family Kinases / Q000235:genetics / Q000378:metabolism*
C534932:Agt protein, mouse; D019390:Arrestins; D012333:RNA, Messenger; D044140:Receptor, Angiotensin, Type 1; D000071557:beta-Arrestins; D000808:Angiotensinogen; D015544:Inositol 1,4,5-Trisphosphate; D019061:src-Family Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3