LEOPARD-type SHP2 mutant Gln510Glu attenuates cardiomyocyte differentiation and promotes cardiac hypertrophy via dysregulation of Akt/GSK-3β/β-catenin signaling
LEOPARD-type SHP2 mutant Gln510Glu attenuates cardiomyocyte differentiation and promotes cardiac hypertrophy via dysregulation of Akt/GSK-3β/β-catenin signaling
复制标题
DOI：
10.1152/ajpheart.00216.2011
复制
发表时间：
2011-10-01
影响因子：
4.8
通讯作者：
Ozono, Keiichi
中科院分区：
文献类型：
--
作者：
Ishida, Hidekazu;Kogaki, Shigetoyo;Ozono, Keiichi
石田H，小垣S，成田J，一森H，纳瓦N，冈田Y，高桥K，Ozono K. LEOPARD型SHP 2突变体Gln 510 Glu通过Akt/GSK-3 β/β-连环蛋白信号失调减弱心肌细胞分化并促进心肌肥大Am J Physiol Heart Circ Physiol 301：H1531-H1539，2011.首次发表于2011年7月29日; doi：10.1152/ajpheart.00216.2011。LEOPARD综合征（LS）是一种常染色体显性遗传性多系统疾病。大多数病例涉及PTPN 11基因突变，该基因编码蛋白质酪氨酸磷酸酶Src同源性2-含有蛋白质磷酸酶2（SHP 2）。LS经常导致严重的肥厚型心肌病（HCM），甚至从胎儿期开始。然而，分子发病机制尚未明确阐明。在这里，我们分析了LS型SHP 2突变体Gln 510 Glu（Q510 E），这表明最严重的类型的HCM在LS中，在心肌细胞分化和形态学变化的作用。我们产生了突变型P19 CL 6细胞系，这是最方便的心肌细胞分化模型，其连续表达SHP 2-Q510 E、SHP 2-D 61 N（努南型突变体）、野生型SHP 2和绿色荧光蛋白（仅天然SHP 2表达）。SHP 2-Q510 E突变体P19 CL 6细胞显示肌原纤维生成显著减弱，增殖活性增加。来自SHP 2-Q510 E突变体的成熟心肌细胞显著大于对照和其他突变体。然而，心脏特异性转录因子（Gata 4、Tbx 5和Nkx2.5）的表达在LS型SHP 2-Q510 E突变体与其他突变体和对照之间没有显著差异。我们的研究结果表明，SHP 2-Q510 E突变体可以分化为心脏祖细胞，但被抑制进行终末分化为成熟的心肌细胞。与此相反，Akt和糖原合成酶激酶（GSK）-3 β磷酸化上调，并在分化后期的细胞核β-连环蛋白高度积累的SHP 2-Q510 E突变体P19 CL 6细胞。在分化后期补充磷酸肌醇3-激酶/Akt抑制剂LY-294002被发现部分恢复肌原纤维生成，同时抑制来自SHP 2-Q510 E突变体的单个成熟心肌细胞大小的增加。我们的研究结果表明，Akt/GSK-3 β/β-catenin通路的失调可能有助于在LS患者中HCM的发病机制，不仅通过单个心脏细胞的肥大变化，而且还通过心脏祖细胞的扩增。
Ishida H, Kogaki S, Narita J, Ichimori H, Nawa N, Okada Y, Takahashi K, Ozono K. LEOPARD-type SHP2 mutant Gln510Glu attenuates cardiomyocyte differentiation and promotes cardiac hypertrophy via dysregulation of Akt/GSK-3 beta/beta-catenin signaling. Am J Physiol Heart Circ Physiol 301: H1531-H1539, 2011. First published July 29, 2011; doi:10.1152/ajpheart.00216.2011.-LEOPARD syndrome (LS) is an autosomal dominant inherited multisystemic disorder. Most cases involve mutations in the PTPN11 gene, which encodes the protein tyrosine phosphatase Src homology 2-containing protein phosphatase 2 (SHP2). LS frequently causes severe hypertrophic cardiomyopathy (HCM), even from the fetal period. However, the molecular pathogenesis has not been clearly elucidated. Here, we analyzed the roles of the LS-type SHP2 mutant Gln510Glu (Q510E), which showed the most severe type of HCM in LS, in cardiomyocyte differentiation, and in morphological changes. We generated mutant P19CL6 cell lines, the most convenient cardiomyocyte differentiation model, which continuously expressed SHP2-Q510E, SHP2-D61N (Noonan-type mutant), wild-type SHP2, and green fluorescent protein (native SHP2 expression only). SHP2-Q510E mutant P19CL6 cells showed significant attenuation of myofibrillogenesis, with increased proliferative activity. Mature cardiomyocytes from the SHP2-Q510E mutant were significantly larger than those of controls and the other mutants. However, expression of cardiac-specific transcriptional factors (Gata4, Tbx5, and Nkx2.5) did not differ significantly between the LS-type SHP2-Q510E mutants and the other mutants and controls. Our results indicate that SHP2-Q510E mutants can differentiate into cardiac progenitors but are inhibited from undergoing terminal differentiation into mature cardiomyocytes. In contrast, Akt and glycogen synthase kinase (GSK)-3 beta phosphorylation were upregulated, and nuclear beta-catenin at the late stage of differentiation was highly accumulated in SHP2-Q510E mutant P19CL6 cells. Supplementation with the phosphoinositide 3-kinase/Akt inhibitor LY-294002 during the late stage of differentiation was found to partially restore myofibrillogenesis while suppressing the increase in size of individual mature cardiomyocytes derived from the SHP2-Q510E mutants. Our findings suggest that dysregulation of the Akt/GSK-3 beta/beta-catenin pathway can contribute to the pathogenesis of HCM in LS patients, not only through hypertrophic changes in individual cardiac cells but also via the expansion of cardiac progenitors.