Aging-related hyperphosphatemia impairs myogenic differentiation and enhances fibrosis in skeletal muscle.
Aging-related hyperphosphatemia impairs myogenic differentiation and enhances fibrosis in skeletal muscle.
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DOI：
10.1002/jcsm.12750
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发表时间：
2021-10
期刊：
影响因子：
--
通讯作者：
Ruiz-Torres MP
中科院分区：
文献类型：
--
作者：
Sosa P;Alcalde-Estévez E;Asenjo-Bueno A;Plaza P;Carrillo-López N;Olmos G;López-Ongil S;Ruiz-Torres MP
高磷酸盐血症与衰老小鼠肌肉减少症的发生有关。我们描述了高磷血症促进的肌源性分化的损伤所涉及的细胞内机制，并分析了这些机制在老年小鼠的肌肉。C2 C12细胞在2%马血清中生长，以促进肌原性分化，在存在或不存在10 mM β-甘油磷酸盐（BGP）的情况下生长7天。在48、72和168 h时分析肌钙蛋白T、配对框7（Pax-7）、成肌因子5（Myf 5）、成肌分化1（MyoD）、成肌蛋白（MyoG）、肌细胞增强因子2（MEF 2C）、P300/CBP相关因子（PCAF）、组蛋白脱乙酰酶1（HDAC 1）、纤连蛋白、波形蛋白和胶原蛋白I。通过Western印迹或通过共聚焦显微镜观察的免疫荧光染色。在5月龄和24月龄C57 BL 6小鼠中进行了小鼠研究。处死前3个月，21月龄小鼠分别喂食标准饲料或含0.6%或0.2%磷酸盐的低磷酸盐饲料。血清磷酸盐浓度通过比色法和前肢力量通过握力试验进行评估。天狼星红染色可见胫前肌纤维化。在腓肠肌中，通过蛋白质印迹法分析MyoG、MEF 2C和纤连蛋白的表达。与对照细胞相比，在BGP存在下分化的细胞显示肌钙蛋白T的表达减少近五倍，并保持较高的Pax-7水平，表明肌源性分化减少。BGP通过增加HDAC 1的表达和减少PCAF的表达，降低Myf 5约50%，并降低MyoD的转录活性。因此，BGP将MyoG和MEF 2C的表达降低至50%。在BGP处理的细胞中发现纤维化标志物如胶原I、波形蛋白和纤连蛋白的表达显著增加。在小鼠中，血清磷（17.24 ± 0.77 mg/dL年轻人; 23.23 ± 0.81 mg/dL老年人; 19.09 ± 0.75 mg/dL老年人低磷饮食）呈负相关（r =-0.515，P = 0.001）与肌力（3.13 ± 0.07gf/g青年，1.70 ± 0.12gf/g老年;与腓肠肌MyoG表达呈正相关（r =-0.535，P = 0.007），与纤维连接蛋白表达呈正相关（r = 0.503，P = 0.001）。老年小鼠胫骨前肌纤维化。用低磷酸盐饮食喂养的老年小鼠显示出相对于相似年龄的对照小鼠改善的肌肉参数。高磷酸盐血症通过抑制MyoD的转录活性损害肌原性分化，并增强培养成肌细胞中纤维化基因的表达。在老年小鼠中进行的实验表明，年龄相关性高磷酸盐血症与生肌因子表达减少和肌肉纤维化相关因子增加之间存在密切关系。
Hyperphosphatemia has been related to the development of sarcopenia in aging mice. We describe the intracellular mechanisms involved in the impairment of the myogenic differentiation promoted by hyperphosphatemia and analyse these mechanisms in the muscle from older mice. C2C12 cells were grown in 2% horse serum in order to promote myogenic differentiation, in the presence or absence of 10 mM beta‐glycerophosphate (BGP) for 7 days. Troponin T, paired box 7 (Pax‐7), myogenic factor 5 (Myf5), myogenic differentiation 1 (MyoD), myogenin (MyoG), myocyte enhancer factor 2 (MEF2C), P300/CBP‐associated factor (PCAF), histone deacetylase 1 (HDAC1), fibronectin, vimentin, and collagen I were analysed at 48, 72, and 168 h, by western blotting or by immunofluorescence staining visualized by confocal microscopy. Studies in mice were performed in 5‐ and 24‐month‐old C57BL6 mice. Three months before sacrifice, 21‐month‐old mice were fed with a standard diet or a low phosphate diet, containing 0.6% or 0.2% phosphate, respectively. Serum phosphate concentration was assessed by a colorimetric method and forelimb strength by a grip test. Fibrosis was observed in the tibialis anterior muscle by Sirius Red staining. In gastrocnemius muscle, MyoG, MEF2C, and fibronectin expressions were analysed by western blotting. Cells differentiated in the presence of BGP showed near five times less expression of troponin T and kept higher levels of Pax‐7 than control cells indicating a reduced myogenic differentiation. BGP reduced Myf5 about 50% and diminished MyoD transcriptional activity by increasing the expression of HDAC1 and reducing the expression of PCAF. Consequently, BGP reduced to 50% the expression of MyoG and MEF2C. A significant increase in the expression of fibrosis markers as collagen I, vimentin, and fibronectin was found in cells treated with BGP. In mice, serum phosphate (17.24 ± 0.77 mg/dL young; 23.23 ± 0.81 mg/dL old; 19.09 ± 0.75 mg/dL old with low phosphate diet) correlates negatively (r = −0.515, P = 0.001) with the muscular strength (3.13 ± 0.07 gf/g young; 1.70 ± 0.12 gf/g old; 2.10 ± 0.09 gf/g old with low phosphate diet) and with the expression of MyoG (r = −0.535, P = 0.007) and positively with the expression of fibronectin (r = 0.503, P = 0.001) in gastrocnemius muscle. The tibialis anterior muscle from old mice showed muscular fibrosis. Older mice fed with a low phosphate diet showed improved muscular parameters relative to control mice of similar age. Hyperphosphatemia impairs myogenic differentiation, by inhibiting the transcriptional activity of MyoD, and enhances the expression of fibrotic genes in cultured myoblasts. Experiments carried out in older mice demonstrate a close relationship between age‐related hyperphosphatemia and the decrease in the expression of myogenic factors and the increase in factors related to muscle fibrosis.
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影响因子：
5.2
作者：
Alcalde-Estevez, Elena;Asenjo-Bueno, Ana;Lopez-Ongil, Susana
通讯作者：
Lopez-Ongil, Susana
影响因子：
64.8
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9.2
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影响因子：
56.9
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Rando, Thomas A.
影响因子：
4.8
作者：
Ohnishi, Mutsuko;Razzaque, M. Shawkat
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Razzaque, M. Shawkat