Jang Sujeong, Cho Hyong-Ho, Park Jong-Seong, Jeong Han-Seong
Department of Physiology, Chonnam National University Medical School, Gwangju 61469, Republic of Korea; Research Institute of Medical Sciences, Chonnam National University, Gwangju 61186, Republic of Korea.
Department of Otolaryngology-Head and Neck Surgery, Chonnam National University Medical School, Gwangju 61469, Republic of Korea; Research Institute of Medical Sciences, Chonnam National University, Gwangju 61186, Republic of Korea.
Neurosci Lett. 2017 Nov 1;660:68-73. doi: 10.1016/j.neulet.2017.09.023. Epub 2017 Sep 12.
Bone marrow-derived mesenchymal stem cells (BM-MSCs), which are characterized by multipotency and self-renewal, are responsible for tissue regeneration and repair. We have previously reported in adipose tissue-derived MSCs that only Wnt5a is enhanced at neurogenic differentiation, and the mechanism of differentiation is dependent on the Wnt5a/JNK pathway; however, the role of Wnt/MAPK pathway is yet to be investigated in neurogenic differentiation in BM-MSCs. We compared the transcriptional expression of Wnt in neurogenic induced-hBM-MSCs (NI-hBM-MSCs) with that in primary hBM-MSCs, using RT-PCR, qPCR, and western blotting. Although the expression of Wnt1 and Wnt2 was unchanged, the expression of Wnt4, Wnt5a, and Wnt11 increased after neurogenic differentiation. In addition, only the expression of frizzled class receptor (Fzd) 3 gene was increased, but not of most of the Fzds and Wnt ligands in NI-hBM-MSCs. Interestingly, Wnt4, Wnt5a, and Wnt11 gene expressions significantly increased in NI-hBM-MSCs by qPCR. In addition, the protein expression level of Wnt4 and Wnt5a, but not Wnt3, increased after neurogenic induction. Furthermore, the expressions of phosphorylated-GSK-3β, ERK1/2, and PKC decreased; however, JNK was activated after neurogenic differentiation. Thus, non-canonical Wnts, i.e., Wnt4, Wnt5a, and Wnt11, regulate neurogenic differentiation through Fzd3 activation and the increase in downstream targets of JNK, which is one of the non-canonical pathways, in hBM-MSCs.
骨髓间充质干细胞（BM-MSCs）具有多能性和自我更新能力，负责组织再生和修复。我们之前报道过，在脂肪组织来源的间充质干细胞中，只有Wnt5a在神经分化时增强，且分化机制依赖于Wnt5a/JNK通路；然而，Wnt/MAPK通路在BM-MSCs神经分化中的作用尚待研究。我们使用逆转录聚合酶链反应（RT-PCR）、定量聚合酶链反应（qPCR）和蛋白质印迹法，比较了神经诱导的人骨髓间充质干细胞（NI-hBM-MSCs）与原代人骨髓间充质干细胞中Wnt的转录表达。虽然Wnt1和Wnt2的表达没有变化，但神经分化后Wnt4、Wnt5a和Wnt11的表达增加。此外，在NI-hBM-MSCs中，只有卷曲蛋白家族受体（Fzd）3基因的表达增加，而大多数Fzds和Wnt配体的表达没有增加。有趣的是，通过qPCR检测发现，NI-hBM-MSCs中Wnt4、Wnt5a和Wnt11基因的表达显著增加。此外，神经诱导后Wnt4和Wnt5a的蛋白表达水平增加，而Wnt3没有增加。此外，磷酸化糖原合成酶激酶-3β（GSK-3β）、细胞外信号调节激酶1/2（ERK1/2）和蛋白激酶C（PKC）的表达降低；然而，神经分化后JNK被激活。因此，非经典Wnt，即Wnt4、Wnt5a和Wnt11，通过激活Fzd3和增加JNK下游靶点来调节hBM-MSCs中的神经分化，JNK是一种非经典通路。
