Christie Kimberly, Koshy Dilip, Cheng Chu, Guo GuiFang, Martinez Jose A, Duraikannu Arul, Zochodne Douglas W
Division of Neurology, University of Alberta.
Division of Neurology, University of Alberta.
Mol Cell Neurosci. 2015 Jul;67:1-12. doi: 10.1016/j.mcn.2015.05.001. Epub 2015 May 12.
Perineuronal satellite cells have an intimate anatomical relationship with sensory neurons that suggests close functional collaboration and mutual support. We examined several facets of this relationship in adult sensory dorsal root ganglia (DRG). Collaboration included the support of process outgrowth by clustering of satellite cells, induction of distal branching behavior by soma signaling, the capacity of satellite cells to respond to distal axon injury of its neighboring neurons, and evidence of direct neuron-satellite cell exchange. In vitro, closely adherent coharvested satellite cells routinely clustered around new outgrowing processes and groups of satellite cells attracted neurite processes. Similar clustering was encountered in the pseudounipolar processes of intact sensory neurons within intact DRG in vivo. While short term exposure of distal growth cones of unselected adult sensory neurons to transient gradients of a PTEN inhibitor had negligible impacts on their behavior, exposure of the soma induced early and substantial growth of their distant neurites and branches, an example of local soma signaling. In turn, satellite cells sensed when distal neuronal axons were injured by enlarging and proliferating. We also observed that satellite cells were capable of internalizing and expressing a neuron fluorochrome label, diamidino yellow, applied remotely to distal injured axons of the neuron and retrogradely transported to dorsal root ganglia sensory neurons. The findings illustrate a robust interaction between intranganglionic neurons and glial cells that involve two way signals, features that may be critical for both regenerative responses and ongoing maintenance.
神经周卫星细胞与感觉神经元存在密切的解剖学关系，这表明它们之间存在紧密的功能协作和相互支持。我们研究了成年感觉背根神经节（DRG）中这种关系的几个方面。协作包括卫星细胞聚集对突起生长的支持、胞体信号诱导远端分支行为、卫星细胞对其相邻神经元远端轴突损伤的反应能力，以及神经元与卫星细胞直接交换的证据。在体外，紧密贴附共同收获的卫星细胞通常会聚集在新长出的突起周围，卫星细胞群会吸引神经突。在体内完整的DRG中，完整感觉神经元的假单极突起中也观察到类似的聚集现象。虽然未选择的成年感觉神经元的远端生长锥短期暴露于PTEN抑制剂的瞬时梯度对其行为影响可忽略不计，但胞体暴露会诱导其远端神经突和分支早期大量生长，这是局部胞体信号的一个例子。反过来，当远端神经元轴突受损时，卫星细胞会通过增大和增殖来感知。我们还观察到，卫星细胞能够内化并表达一种神经元荧光染料标记物——双脒基黄，该标记物被远程应用于神经元远端受损轴突，并逆行运输到背根神经节感觉神经元。这些发现说明了神经节内神经元与神经胶质细胞之间存在强大的相互作用，涉及双向信号，这些特征可能对再生反应和持续维持都至关重要。
