Angiotensin-(1-7) receptor Mas is an essential modulator of extracellular matrix protein expression in the heart
Angiotensin-(1-7) receptor Mas is an essential modulator of extracellular matrix protein expression in the heart
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DOI：
10.1016/j.regpep.2012.01.001
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发表时间：
2012-04-10
影响因子：
--
通讯作者：
Kitten, Gregory T.
中科院分区：
文献类型：
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作者：
Gava, Elisandra;de Castro, Carlos Henrique;Kitten, Gregory T.
在这项研究中，我们研究了血管紧张素-(1-7)受体Mas或血管紧张素II受体AT(2)基因缺失对新生小鼠和成年小鼠心房、右心室和房室（AV）瓣膜中特异性细胞外基质（ECM）蛋白表达的影响。采用免疫荧光标记和共聚焦显微镜对1111型胶原、VI型胶原和纤维连接蛋白进行定量分析。小天狼星红染色对胶原蛋白的整体分布模式进行组织学评价。western blot检测ECM蛋白、金属蛋白酶（MMP）、ERK1/2和p38水平。明胶酶谱法测定MMP-2和MMP-9活性。我们观察到，新生Mas（+/+）小鼠心脏的右心室和房室瓣膜中I型胶原蛋白和III型胶原蛋白的相对水平明显较高（例如，Mas（+/+）小鼠右心室I型胶原蛋白：85.28 +/- 6.66 vs 43.50 +/- 4.41任意单位）。相反，Mas（-/-）小鼠右心室和房室瓣膜的VI型胶原水平较低。成年Mas（-/-）小鼠心脏呈现出与新生儿相似的模式。两组间ECM蛋白水平无明显差异。同样，在AT2敲除小鼠心脏中，未观察到ECM水平的变化。虽然Mas的缺失会导致新生儿心脏中MMP-2活性形式水平的显著降低，成年Mas（-/-）小鼠心脏中MMP-2和MMP-9活性形式水平的降低，但与对照组相比，MMP酶活性没有显著差异。在新生和成年Mas（-/-）小鼠的心脏中，活性磷酸化形式的ERK1/2和p38的水平更高。这些观察结果表明，Mas参与了心室心肌和房室瓣膜内特异性ECM蛋白的选择性表达。ECM谱的改变可能会改变结缔组织框架，并导致Mas（-/-）小鼠心脏功能下降。(C) 2012 Elsevier B.V.版权所有
In this study we investigated the effects of genetic deletion of the Angiotensin-(1-7) receptor Mas or the Angiotensin II receptor AT(2) on the expression of specific extracellular matrix (ECM) proteins in atria, right ventricles and atrioventricular (AV) valves of neonatal and adult mice. Quantification of collagen types 1,111 and VI and fibronectin was performed using immunofluorescence-labeling and confocal microscopy. Picrosirius red staining was used for the histological assessment of the overall collagen distribution pattern. ECM proteins, metalloproteinases (MMP), ERK1/2 and p38 levels were quantified by western blot analysis. Gelatin zymography was used to evaluate the activity of MMP-2 and MMP-9. We observed that the relative levels of collagen types I and III and fibronectin are significantly higher in both the right ventricle and AV valves of neonatal Mas(-/-) mouse hearts (e.g., collagen type I: 85.28 +/- 6.66 vs 43.50 +/- 4.41 arbitrary units in the right ventricles of Mas(+/+) mice). Conversely, the level of collagen type VI was lower in the right ventricle and AV valves of Mas(-/-) mice. Adult Mas(-/-) mouse hearts presented similar patterns as observed in neonates. No significant differences in ECM protein level were detected in atria. Likewise, no changes in ECM levels were observed in AT2 knockout mouse hearts. Although deletion of Mas induced a significant reduction in the level of the active form of MMP-2 in neonate hearts and a reduction of both MMP-2 and MMP-9 in adult Mas(-/-) mice, no significant differences were observed in MMP enzymatic activities when compared to controls. The levels of the active, phosphorylated forms of ERK1/2 and p38 were higher in hearts of both neonatal and adult Mas(-/-) mice. These observations suggest that Mas is involved in the selective expression of specific ECM proteins within both the ventricular myocardium and AV valves. The changes in the ECM profile may alter the connective tissue framework and contribute to the decreased cardiac performance observed in Mas(-/-) mice. (C) 2012 Elsevier B.V. All rights reserved.