Role of KCC3 in Schwann cell development

描述（由申请人提供）：我们实验室培育了K+-Cl-contransporter-3 （KCC3）敲除小鼠，这些小鼠表现出严重的运动缺陷。这种表型反映了患有安德曼综合征（ACCPN）神经系统疾病的人类KCC3基因突变患者的周围神经病变。两者都表现出周围神经的髓鞘异常，如髓鞘发育不足、脱髓鞘和纤维变性。虽然出生后20天及以上的小鼠坐骨神经中检测不到KCC3，但初步免疫染色结果显示，KCC3在发育早期雪旺细胞（SC）体中高表达，这与SC迁移、增殖和髓鞘形成时期相对应。因此，我们假设KCC3在其中一个或多个过程中起着关键作用。功能性SCs是至关重要的，因为正常的髓鞘形成是正常动作电位传导所必需的。本提案的目标是定义KCC3在SC发展中的作用。虽然其生理作用尚不清楚，但KCC3介导K+和Cl-离子的电中性运动，可以调节细胞体积，并与细胞增殖有关。我们将首先确定KCC3在周围神经中的确切定位和表达模式。然后，为了验证我们的假设，我们将比较野生型和KCC3-/- sc之间的运动性、髓鞘形成能力、增殖和凋亡水平，以了解sc中的共转运蛋白功能。这项研究也将揭示周围神经发育的新信息。

DESCRIPTION (provided by applicant): Our laboratory has generated K+-Cl-contransporter-3 (KCC3) knockout mice, which exhibit severe locomotor deficits. This phenotype mirrors the peripheral neuropathy in patients with mutations in the human KCC3 gene who suffer from a neurological disorder termed Andermann syndrome, or ACCPN. Both show myelination abnormalities in peripheral nerves, e.g. hypomyelination, demyelination, and fiber degeneration. Although KCC3 is undetectable in sciatic nerve of mice postnatal 20 days and older, preliminary immunostaining results show that KCC3 is highly expressed in Schwann cell (SC) bodies during early development, which corresponds to the period of SC migration, proliferation, and myelination. Thus we hypothesize that KCC3 lays a critical role in one or more of these processes. Functional SCs are crucial since proper myelination is necessary for normal action potential conduction. The goal of this proposal is to define the role of KCC3 in SC development. Although its physiological role is unknown, KCC3 mediates the electroneutral movement of K+ and Cl- ions, can regulate cell volume, and is associated with cell proliferation. We will first determine the exact localization and expression pattern of KCC3 in peripheral nerves. Then to test our hypothesis, we will compare motility, myelination ability, and proliferation and apoptosis levels between wild type and KCC3-/-SCs in order to understand cotransporter function in SCs. This study will also reveal new information on peripheral nerve development.