Functional responses to angiotensin Ⅱ (AT-Ⅱ) were determined in aortic vascular smooth muscle cells (VSMCs) from experimental cirrhotic rats. Our data showed that AT-Ⅱ-stimulated extracellular acidification rate (E...Functional responses to angiotensin Ⅱ (AT-Ⅱ) were determined in aortic vascular smooth muscle cells (VSMCs) from experimental cirrhotic rats. Our data showed that AT-Ⅱ-stimulated extracellular acidification rate (ECAR), which was measured by Cytosensor microphysiometry, was significantly reduced in the aortic VSMCs from the cirrhotic rats as compared to those from the control animals. The ability of AT-Ⅱ to promote formation of inositol phosphates, the second messenger produced by the activation of Gq-coupled receptors, was also considerably suppressed in the cirrhotic VSMCs. Furthermore, the maximal p42/44 MAPK phosphorylation stimulated by AT-Ⅱ was significantly reduced in the cirrhotic VSMCs in contrast to that in the normal VSMCs. Taken together, our data clearly demonstrated that the functional responses to AT-Ⅱ was severely suppressed in aortic VSMCs in cirrhosis, indicating the impairment of general Gq-coupled receptor signaling and subsequent biological function in the cirrhotic VSMCs.展开更多
The aim of the present study is to address the effect of rapamycin on abdominal aortic aneurysm（AAA） and the potential mechanisms. A clinically relevant AAA model was induced in apolipoprotein E-deficient（ApoE-/-）...The aim of the present study is to address the effect of rapamycin on abdominal aortic aneurysm（AAA） and the potential mechanisms. A clinically relevant AAA model was induced in apolipoprotein E-deficient（ApoE-/-） mice, in which miniosmotic pump was implanted subcutaneously to deliver angiotensin Ⅱ（Ang Ⅱ） for 14 days. Male ApoE-/-mice were randomly divided into 3 groups： saline infusion, Ang Ⅱ infusion, and Ang Ⅱ infusion plus intraperitoneal injection of rapamycin. The diameter of the supra-renal abdominal aorta was measured by ultrasonography at the end of the infusion. Then aortic tissue was excised and examined by Western blotting and histoimmunochemistry. Ang Ⅱ with or without rapamycin treatment was applied to the cultured vascular smooth muscle cells（VSMCs） in vitro. The results revealed that rapamycin treatment significantly attenuated the incidence of Ang Ⅱinduced-AAA in ApoE-/-mice. Histologic analysis showed that rapamycin treatment decreased disarray of elastin fibers and VSMCs hyperplasia in the medial layer. Immunochemistry staining and Western blotting documented the increased phospho-ERKl/2 and ERK1/2 expression in aortic walls in Ang Ⅱ induced-AAA,as well as in human lesions. Whereas in the rapamycintreated group, decreased phospho-ERK1/2 expression level was detected. Moreover, rapamycin reversed Ang Ⅱ-induced VSMCs phenotypic change both in vivo and in vitro. Based on those results, we confirmed that rapamycin therapy suppressed Ang Ⅱ-induced AAA formation in mice, partially via VSMCs phenotypic modulation and down-regulation of ERK1/2 activity.展开更多
文摘Functional responses to angiotensin Ⅱ (AT-Ⅱ) were determined in aortic vascular smooth muscle cells (VSMCs) from experimental cirrhotic rats. Our data showed that AT-Ⅱ-stimulated extracellular acidification rate (ECAR), which was measured by Cytosensor microphysiometry, was significantly reduced in the aortic VSMCs from the cirrhotic rats as compared to those from the control animals. The ability of AT-Ⅱ to promote formation of inositol phosphates, the second messenger produced by the activation of Gq-coupled receptors, was also considerably suppressed in the cirrhotic VSMCs. Furthermore, the maximal p42/44 MAPK phosphorylation stimulated by AT-Ⅱ was significantly reduced in the cirrhotic VSMCs in contrast to that in the normal VSMCs. Taken together, our data clearly demonstrated that the functional responses to AT-Ⅱ was severely suppressed in aortic VSMCs in cirrhosis, indicating the impairment of general Gq-coupled receptor signaling and subsequent biological function in the cirrhotic VSMCs.
基金supported by grants from the National Natural Science Foundation of China(No.81570325)the Fundamental Research Funds for the Central Universities
文摘The aim of the present study is to address the effect of rapamycin on abdominal aortic aneurysm（AAA） and the potential mechanisms. A clinically relevant AAA model was induced in apolipoprotein E-deficient（ApoE-/-） mice, in which miniosmotic pump was implanted subcutaneously to deliver angiotensin Ⅱ（Ang Ⅱ） for 14 days. Male ApoE-/-mice were randomly divided into 3 groups： saline infusion, Ang Ⅱ infusion, and Ang Ⅱ infusion plus intraperitoneal injection of rapamycin. The diameter of the supra-renal abdominal aorta was measured by ultrasonography at the end of the infusion. Then aortic tissue was excised and examined by Western blotting and histoimmunochemistry. Ang Ⅱ with or without rapamycin treatment was applied to the cultured vascular smooth muscle cells（VSMCs） in vitro. The results revealed that rapamycin treatment significantly attenuated the incidence of Ang Ⅱinduced-AAA in ApoE-/-mice. Histologic analysis showed that rapamycin treatment decreased disarray of elastin fibers and VSMCs hyperplasia in the medial layer. Immunochemistry staining and Western blotting documented the increased phospho-ERKl/2 and ERK1/2 expression in aortic walls in Ang Ⅱ induced-AAA,as well as in human lesions. Whereas in the rapamycintreated group, decreased phospho-ERK1/2 expression level was detected. Moreover, rapamycin reversed Ang Ⅱ-induced VSMCs phenotypic change both in vivo and in vitro. Based on those results, we confirmed that rapamycin therapy suppressed Ang Ⅱ-induced AAA formation in mice, partially via VSMCs phenotypic modulation and down-regulation of ERK1/2 activity.
