TrkA regulates the regenerative capacity of bone marrow stromal stem cells in nerve grafts
TrkA regulates the regenerative capacity of bone marrow stromal stem cells in nerve grafts
复制标题
TrkA 调节神经移植物中骨髓基质干细胞的再生能力
DOI：
10.4103/1673-5374.257540
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发表时间：
2019-10-01
影响因子：
6.1
通讯作者：
Wang, Dong
中科院分区：
文献类型：
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作者：
Zheng, Mei-Ge;Sui, Wen-Yuan;Wang, Dong
我们以前证明过表达原肌球蛋白受体激酶A（TrkA）促进神经移植物中骨髓基质干细胞的存活和雪旺细胞样分化，从而增强周围神经的再生和功能恢复。在本研究中，我们研究了TrkA在骨髓基质干细胞接种到神经移植物中的神经保护作用的分子机制。用表达大鼠TrkA、TrkA-shRNA或相应对照的重组慢病毒载体感染来自Sprague-Dawley大鼠的骨髓基质干细胞。然后将细胞接种到同种异体大鼠脱细胞同种异体神经移植物中，用于桥接1cm的右侧坐骨神经缺损。术后8周，苏木精-伊红染色显示，与对照组相比，TrkA过表达组细胞和纤维排列更加密集均匀，而TrkA-shRNA组细胞和纤维相对稀疏，排列紊乱。Western blot检测结果显示，与对照组相比，TrkA过表达组的髓鞘标志物、髓鞘碱性蛋白和轴突标志物神经丝200的表达均明显增强。TrkA过表达组还具有更高水平的各种信号分子，包括TrkA、pTrkA（Tyr 490）、细胞外信号调节激酶1/2（Erk 1/2）、pErk 1/2（Thr 202/Tyr 204）以及抗凋亡蛋白Bcl-2和Bcl-xL。相反，这些蛋白质下调，而促凋亡因子Bax和Bad上调，在TrkA-shRNA组。TrkA效应物Akt和pAkt（Ser 473）的水平在各组之间没有差异。这些结果表明，TrkA通过上调Erk/Bcl-2通路增强骨髓基质干细胞的存活和再生能力。所有程序均于2014年12月获得中国深圳大学动物伦理与福利委员会批准（批准号AEWC-2014-001219）。
We previously demonstrated that overexpression of tropomyosin receptor kinase A (TrkA) promotes the survival and Schwann cell-like differentiation of bone marrow stromal stem cells in nerve grafts, thereby enhancing the regeneration and functional recovery of the peripheral nerve. In the present study, we investigated the molecular mechanisms underlying the neuroprotective effects of TrkA in bone marrow stromal stem cells seeded into nerve grafts. Bone marrow stromal stem cells from Sprague-Dawley rats were infected with recombinant lentivirus vector expressing rat TrkA, TrkA-shRNA or the respective control. The cells were then seeded into allogeneic rat acellular nerve allografts for bridging a 1-cm right sciatic nerve defect. Then, 8 weeks after surgery, hematoxylin and eosin staining showed that compared with the control groups, the cells and fibers in the TrkA overexpressing group were more densely and uniformly arranged, whereas they were relatively sparse and arranged in a disordered manner in the TrkA-shRNA group. Western blot assay showed that compared with the control groups, the TrkA overexpressing group had higher expression of the myelin marker, myelin basic protein and the axonal marker neurofilament 200. The TrkA overexpressing group also had higher levels of various signaling molecules, including TrkA, pTrkA (Tyr490), extracellular signal-regulated kinases 1/2 (Erk1/2), pErk1/2 (Thr202/Tyr204), and the anti-apoptotic proteins Bcl-2 and Bcl-xL. In contrast, these proteins were downregulated, while the pro-apoptotic factors Bax and Bad were upregulated, in the TrkA-shRNA group. The levels of the TrkA effectors Akt and pAkt (Ser473) were not different among the groups. These results suggest that TrkA enhances the survival and regenerative capacity of bone marrow stromal stem cells through upregulation of the Erk/Bcl-2 pathway. All procedures were approved by the Animal Ethical and Welfare Committee of Shenzhen University, China in December 2014 (approval No. AEWC-2014-001219).