Xinxiang Key Laboratory of Neural Development, Stem Cells & Biotherapy Engineering Research Center of Henan, College of Life Science and Technology, Xinxiang Medical University, Xinxiang, China.
Henan Key Laboratory of Medical Tissue Regeneration, Xinxiang, China.
J Cell Mol Med. 2019 May;23(5):3549-3562. doi: 10.1111/jcmm.14254. Epub 2019 Mar 4.
Sonic hedgehog (SHH) is a vertebrate homologue of the secreted Drosophila protein hedgehog and is expressed by the notochord and floor plate in the developing spinal cord. Sonic hedgehog provides signals relevant for positional information, cell proliferation and possibly cell survival, depending on the time and location of expression. Although the role of SHH in providing positional information in the neural tube has been experimentally proven, the underlying mechanism remains unclear. In this study, in ovo electroporation was employed in the chicken spinal cord during chicken embryo development. Electroporation was conducted at stage 17 (E2.5), after electroporation the embryos were continued incubating to stage 28 (E6) for sampling, tissue fixation with 4% paraformaldehyde and frozen sectioning. Sonic hedgehog and related protein expressions were detected by in situ hybridization and fluorescence immunohistochemistry and the results were analysed after microphotography. Our results indicate that the ectopic expression of SHH leads to ventralization in the spinal cord during chicken embryonic development by inducing abnormalities in the structure of the motor column and motor neuron integration. In addition, ectopic SHH expression inhibits the expression of dorsal transcription factors and commissural axon projections. The correct location of SHH expression is vital to the formation of the motor column. Ectopic expression of SHH in the spinal cord not only affects the positioning of motor neurons, but also induces abnormalities in the structure of the motor column. It leads to ventralization in the spinal cord, resulting in the formation of more ventral neurons forming during neuronal formation.
sonic hedgehog (SHH) 是脊椎动物与果蝇蛋白 hedgehog 同源的蛋白，在发育中的脊髓中由脊索和基板表达。 sonic hedgehog 提供与位置信息、细胞增殖和可能的细胞存活相关的信号，具体取决于表达的时间和位置。尽管 SHH 在神经管中提供位置信息的作用已在实验中得到证实，但潜在的机制仍不清楚。在这项研究中，在鸡胚胎发育期间，在鸡胚脊髓中进行了鸡胚阶段 17（E2.5）的胚胎电穿孔。电穿孔后，将胚胎继续孵育至鸡胚阶段 28（E6）进行取样，用 4%多聚甲醛固定组织并进行冷冻切片。通过原位杂交和荧光免疫组织化学检测 sonic hedgehog 和相关蛋白的表达，并在显微摄影后进行分析。我们的结果表明，通过诱导运动柱结构异常和运动神经元整合，异位表达 sonic hedgehog 会导致鸡胚发育过程中脊髓的腹侧化。此外，异位 SHH 表达抑制背侧转录因子的表达和连合轴突投射。SHH 表达的正确位置对于运动柱的形成至关重要。脊髓中的异位 SHH 表达不仅会影响运动神经元的定位，还会导致运动柱结构异常。这会导致脊髓腹侧化，从而在神经元形成过程中形成更多的腹侧神经元。
