Fan Guang-Pu, Wang Wei, Zhao Hui, Cai Lin, Zhang Pei-De, Yang Zi-He, Zhang Jing, Wang Xu
Cell Physiol Biochem. 2015;37(2):515-26. doi: 10.1159/000430373.
To investigate the role of focal adhesion kinase (FAK)-mediated signaling in hypoxia-induced cardiac fibroblasts (CFs) differentiation and cardiac fibrosis post-myocardial infarction (MI) on a mice model.
CFs of neonatal C57BL/6 mice were treated under normoxic, hypoxic, or hypoxic+PP2 (known as a Src kinase family inhibitor) conditions. Gene expressions of FAK, alpha-smooth muscle actin (α-SMA) and collagen type I alpha 1 (Col1α1), or α-SMA and vimentin levels were performed by RT-PCR and immunofluorescence staining, respectively. Thirty mice were surgically treated into Sham (n=7) and MI (n=23) groups; and FAK inhibitor PF-562271 was given to six survivor MI mice (as PF group, from 15 survivors). Heart function and collagenous tissues were examined by echocardiography, as well as by Masson‘s trichrome and Sirius red staining, respectively. Type I collagen, FAK protein, mTOR, ERK1/2, AKT, P70S6K and phospho-FAK levels were also analyzed.
FAK inhibition with PP2 significantly decreased CFs differentiation and collagen synthesis under hypoxia treatment. In vivo, PF-562271 treatment resulted in fibrosis attenuation; however, deteriorated heart function of MI mice could not be significantly improved. PF-562271 may affect phospho-mTOR (p<0.05), phospho-ERK1/2 (p<0.01), phospho-AKT (p<0.001) and phospho-P70S6K (p<0.05) to exert its benefits. FAK can be activated either under hypoxia in CFs or MI in a mouse model to promote fibrosis. However, pharmacological inhibition of FAK can attenuate fibrosis response.
This study provides novel evidence that FAK inhibition may become a promising pharmaceutical strategy to attenuate fibrosis post-MI.
在小鼠模型上研究黏着斑激酶（FAK）介导的信号传导在缺氧诱导的心肌成纤维细胞（CFs）分化及心肌梗死后（MI）心脏纤维化中的作用。
将新生C57BL/6小鼠的CFs分别置于常氧、缺氧或缺氧+PP2（一种已知的Src激酶家族抑制剂）条件下处理。分别通过逆转录聚合酶链反应（RT-PCR）和免疫荧光染色检测FAK、α-平滑肌肌动蛋白（α-SMA）和I型胶原蛋白α1（Col1α1）的基因表达，或α-SMA和波形蛋白水平。将30只小鼠手术分为假手术组（n = 7）和心肌梗死组（n = 23）；给6只存活的心肌梗死小鼠给予FAK抑制剂PF-562271（作为PF组，来自15只存活小鼠）。分别通过超声心动图以及Masson三色染色和天狼星红染色检查心脏功能和胶原组织。还分析了I型胶原蛋白、FAK蛋白、哺乳动物雷帕霉素靶蛋白（mTOR）、细胞外信号调节激酶1/2（ERK1/2）、蛋白激酶B（AKT）、核糖体蛋白S6激酶（P70S6K）和磷酸化FAK水平。
在缺氧处理下，用PP2抑制FAK可显著降低CFs分化和胶原合成。在体内，PF-562271治疗导致纤维化减轻；然而，心肌梗死小鼠恶化的心脏功能未能得到显著改善。PF-562271可能通过影响磷酸化mTOR（p < 0.05）、磷酸化ERK1/2（p < 0.01）、磷酸化AKT（p < 0.001）和磷酸化P70S6K（p < 0.05）发挥其作用。在CFs缺氧或小鼠模型心肌梗死情况下，FAK均可被激活以促进纤维化。然而，对FAK的药理抑制可减轻纤维化反应。
本研究提供了新的证据，表明抑制FAK可能成为减轻心肌梗死后纤维化的一种有前景的药物策略。
