LIM Kinase, a Newly Identified Regulator of Presynaptic Remodeling by Rod Photoreceptors After Injury.
LIM Kinase, a Newly Identified Regulator of Presynaptic Remodeling by Rod Photoreceptors After Injury.
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DOI：
10.1167/iovs.15-17278
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发表时间：
2015-12
影响因子：
4.4
通讯作者：
Weiwei Wang;E. Townes‐Anderson
中科院分区：
文献类型：
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作者：
Weiwei Wang;E. Townes‐Anderson
视网膜脱离和视网膜复位时，视杆细胞的轴突终末回缩，并产生神经炎芽。本研究探讨了LIM激酶（LIMK），RhoA和Rac通路的组成部分，在突触前结构重建的杆光感受器的作用。方法采用Western blot和共聚焦显微镜检测磷酸化LIMK（p-LIMK）在蝾螈视网膜中的表达。在用上游调节剂ROCK和p21激活激酶（Pak）的抑制剂（Y27632和IPA-3）和直接LIMK抑制剂（BMS-5）处理的分离的视杆光感受器中评估培养3天后前7小时内的轴突长度和突起生长。猪视网膜外植体也用BMS-5处理，并在脱离后24小时进行分析。由于Ca 2+内流有助于轴突收缩，在尼卡地平的一些实验中，L-型通道被阻断。结果磷酸化的LIMK存在于收缩过程中的视杆终末和新生突起中。通过抑制LIMK或其调节剂ROCK和Pak，7小时以上的轴突收缩显著减少。LIMK或Pak抑制，特别是在杆细胞的基底（轴突轴承）区域的过程中的增长减少。结合Ca 2+通道和LIMK抑制对回缩没有额外的影响，但在3天后进一步抑制发芽。在分离的猪视网膜中，LIMK抑制减少了视杆轴突回缩并改善了视网膜形态。结论：因此，无论是轴突回缩还是神经炎生长形式的结构重塑都需要LIMK活性。LIM激酶抑制可能具有降低视网膜损伤后病理性杆末端可塑性的治疗潜力。
PURPOSE Rod photoreceptors retract their axon terminals and develop neuritic sprouts in response to retinal detachment and reattachment, respectively. This study examines the role of LIM kinase (LIMK), a component of RhoA and Rac pathways, in the presynaptic structural remodeling of rod photoreceptors. METHODS Phosphorylated LIMK (p-LIMK), the active form of LIMK, was examined in salamander retina with Western blot and confocal microscopy. Axon length within the first 7 hours and process growth after 3 days of culture were assessed in isolated rod photoreceptors treated with inhibitors of upstream regulators ROCK and p21-activated kinase (Pak) (Y27632 and IPA-3) and a direct LIMK inhibitor (BMS-5). Porcine retinal explants were also treated with BMS-5 and analyzed 24 hours after detachment. Because Ca2+ influx contributes to axonal retraction, L-type channels were blocked in some experiments with nicardipine. RESULTS Phosphorylated LIMK is present in rod terminals during retraction and in newly formed processes. Axonal retraction over 7 hours was significantly reduced by inhibition of LIMK or its regulators, ROCK and Pak. Process growth was reduced by LIMK or Pak inhibition especially at the basal (axon-bearing) region of the rod cells. Combining Ca2+ channel and LIMK inhibition had no additional effect on retraction but did further inhibit sprouting after 3 days. In detached porcine retina, LIMK inhibition reduced rod axonal retraction and improved retinal morphology. CONCLUSIONS Thus structural remodeling, in the form of either axonal retraction or neuritic growth, requires LIMK activity. LIM kinase inhibition may have therapeutic potential for reducing pathologic rod terminal plasticity after retinal injury.