Sanna Maria Domenica, Ghelardini Carla, Galeotti Nicoletta
Department of Neurosciences, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, Viale G. Pieraccini 6, 50139 Florence, Italy.
Department of Neurosciences, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, Viale G. Pieraccini 6, 50139 Florence, Italy.
Brain Res. 2017 Mar 15;1659:55-63. doi: 10.1016/j.brainres.2017.01.019. Epub 2017 Jan 19.
Up-regulation of brain-derived neurotrophic factor (BDNF) synthesis is an important mechanism of peripheral nerve regeneration after injury. However, the cellular and molecular mechanisms underlying this process are not fully understood. This study examines the role of BDNF in the spared nerve injury (SNI) mice model. Protein expression and cellular localization were investigated in the dorsal root ganglia (DRG) and spinal cord by western blotting and immunofluorescence experiments respectively. BDNF protein was markedly increased 3 and 7days post-injury in the spinal cord and DRG. Following nerve injury sensory neurons produce molecules to promote regeneration, such as growth-associated protein 43 (GAP-43) and cytoskeletal proteins. Our results show that the expression of GAP-43 was increased in the DRG and spinal cord while, an increased of p-NFH content was detected in the spinal cord, with no modification in the DRG. Both events were counteracted by the administration of an anti-BDNF antibody. In DRG of SNI mice we also detected an increase of HuD expression, a RNA-binding protein known to stabilize BDNF and GAP-43 mRNA. Silencing of HuD prevented the nerve injury-induced BDNF and GAP-43 enhanced expression in the DRG. HuD-mediated BDNF synthesis in the primary sensory neurons, is followed by an anterograde transport of the neurotrophin to the central terminals of the primary afferents in the spinal dorsal horn, to modulate GAP-43 and NFH activation. Our data suggest that BDNF, GAP-43 and p-NFH proteins increase are linked events required for the enhanced regeneration after nerve injury.
脑源性神经营养因子（BDNF）合成的上调是损伤后周围神经再生的重要机制。然而，这一过程背后的细胞和分子机制尚未完全明确。本研究考察了BDNF在 spared 神经损伤（SNI）小鼠模型中的作用。分别通过蛋白质印迹法和免疫荧光实验研究背根神经节（DRG）和脊髓中的蛋白质表达及细胞定位。损伤后 3 天和 7 天，脊髓和 DRG 中的 BDNF 蛋白显著增加。神经损伤后，感觉神经元会产生促进再生的分子，如生长相关蛋白 43（GAP - 43）和细胞骨架蛋白。我们的结果显示，DRG 和脊髓中 GAP - 43 的表达增加，同时脊髓中检测到 p - NFH 含量增加，而 DRG 中无变化。这两个事件均被抗 BDNF 抗体的给药所抵消。在 SNI 小鼠的 DRG 中，我们还检测到 HuD 表达增加，HuD 是一种已知可稳定 BDNF 和 GAP - 43 mRNA 的 RNA 结合蛋白。沉默 HuD 可阻止神经损伤诱导的 DRG 中 BDNF 和 GAP - 43 表达增强。初级感觉神经元中 HuD 介导的 BDNF 合成之后，神经营养因子会顺行运输至脊髓背角初级传入神经的中枢终末，以调节 GAP - 43 和 NFH 的激活。我们的数据表明，BDNF、GAP - 43 和 p - NFH 蛋白的增加是神经损伤后增强再生所需的相关事件。
