Targeting the microtubule cytoskeleton to promote cavernous nerve regeneration and erectile function after injury

摘要 我们最近发表了一项体外研究，确定fidgetin-like 2(Fl2)是一种新的微管调节因子 动力学，对轴突生长和神经再生有抑制作用[1]。由于Fl2-耗竭有轴突 在体外，我们测试了Fl2是否可以靶向促进神经再生 海绵体神经损伤的啮齿动物模型。中枢神经系统是一种副交感神经，调节血流以 阴茎和阴茎通常在根治性前列腺切除术(RP)的手术过程中受损，导致 勃起功能障碍(ED)。值得注意的是，在这些啮齿动物模型中，在CN损伤的位置和时间，Fl2-耗竭 导致可见神经再生加速，伴随着勃起功能结果的改善。然而， 轴突生长只是再生功能周围神经的复杂过程中的一个组成部分， 它还涉及多种辅助细胞类型的招募和活动，如雪旺细胞，免疫 细胞和内皮细胞[2，3]。在其他已发表的研究中，我们已经证明了Fl2可以调节运动 以及几种细胞类型的迁移[4]。因此，我们假设，Fl2- 耗竭促进CN再生和改善损伤后勃起功能结局 多方面的，包括关键细胞类型加速迁移到损伤部位，除了增强 轴突生长。我们将使用体外和体内模型来检验这一假说，并确认 幼年和老年动物CN修复功能的机制(更适合于男性 行快速放射治疗)。 我们将通过两个具体目标来检验我们的假设。在目标1中，我们将确定加速神经 Fl2缺失导致的再生与雪旺细胞、免疫细胞和 内皮细胞到CN损伤部位，如果衰老影响这些附属细胞类型的募集。在AIM 2我们将确定靶向消耗Fl2的能力，以促进CN再生，保存阴茎 RP大鼠模型的构筑和勃起功能的恢复。 我们的研究将使我们更好地理解Fl2-耗尽促进 RP后CN的修复和勃起功能的恢复，以及衰老是否影响这些机制。通过理解 这些机制，我们将可能确定新的治疗策略，不仅治疗，而且还预防， 在RP之后进行ED。

Abstract We recently published in vitro studies identifying Fidgetin-like 2 (FL2) as a novel regulator of microtubule dynamics, with an inhibitory effect on axonal growth and nerve regeneration [1]. Since FL2-depletion had axonal growth-promoting effects in vitro, we tested whether FL2 could be targeted to promote nerve regeneration in a rodent model of cavernous nerve (CN) injury. The CNs are parasympathetic nerves that regulate blood flow to the penis and are commonly damaged during the surgical procedures of radical prostatectomy (RP), resulting in erectile dysfunction (ED). Remarkably, in these rodent models, FL2-depletion at the site and time of CN injury led to accelerated visible nerve regeneration, accompanied by improved erectile function outcomes. However, axonal outgrowth is only one component in the complex process of regenerating functional peripheral nerves, which also involves recruitment and activity of multiple accessory cell-types, such as Schwann cells, immune cells, and endothelial cells [2, 3]. In other published studies, we have demonstrated that FL2 can regulate motility and migration of several cell types [4]. Therefore, we hypothesize that the mechanism by which FL2- depletion promotes CN regeneration and improves erectile function outcomes following injury is multi- faceted, involving accelerated migration of key cell types to the site of injury, in addition to enhancing axonal growth. We will test this hypothesis using both in vitro and in vivo models and confirm that the mechanisms of CN repair function in both young and older animals (more appropriate to the age at which men undergo RP). We will test our hypothesis through two Specific Aims. In Aim 1, we will determine if accelerated nerve regeneration by FL2-depletion is associated with increased migration of Schwann cells, immune cells, and endothelial cells to the site of CN injury and if aging affects the recruitment of these accessory cell-types. In Aim 2 we will determine the ability of targeted FL2-depletion to promote CN-regeneration, preserve penile architecture and recover erectile function in rat models of RP. Our research will lead to greater understanding of the underlying mechanisms by which FL2-depletion promotes CN repair and recovery of erectile function after RP, and if aging affects these mechanisms. By understanding these mechanisms, we will potentially identify novel therapeutic strategies not only to treat, but also to prevent, ED following RP.