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

摘要 我们最近发表了体外研究，确定Fidgetin-like 2（FL 2）作为一种新型的微管调节剂 动力学，对轴突生长和神经再生具有抑制作用[1]。由于FL 2缺失导致轴突 在体外的生长促进作用，我们测试了FL 2是否可以靶向促进神经再生， 海绵体神经（CN）损伤的啮齿动物模型。CN是调节血液流动的副交感神经， 在根治性阴茎切除术（RP）的手术过程中， 勃起功能障碍（艾德）。值得注意的是，在这些啮齿类动物模型中，CN损伤部位和时间的FL 2消耗 导致加速可见的神经再生，伴随着改善勃起功能的结果。然而，在这方面， 轴突生长只是再生功能性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募集和活性，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FL 2可以调节运动性， 和几种细胞类型的迁移[4]。因此，我们假设FL 2- 耗尽促进CN再生和改善损伤后勃起功能的结果是多方面的， 多方面的，涉及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设，并证实 CN修复功能的机制在年轻和老年动物（更适合的年龄，在男性 进行RP）。 我们将通过两个具体目标来检验我们的假设。在目标1中，我们将确定是否加速神经 通过FL 2耗竭的再生与雪旺细胞、免疫细胞和巨噬细胞的迁移增加有关。 这可能是因为年龄的增长会影响到CN损伤部位的内皮细胞，以及是否会影响这些辅助细胞类型的募集。在Aim中 2我们将确定靶向FL 2-耗竭促进CN-再生，保护阴茎 重建和恢复勃起功能。 我们的研究将导致更好地理解FL 2缺失促进细胞凋亡的潜在机制。 CN修复和RP后勃起功能的恢复，以及衰老是否影响这些机制。通过了解 这些机制，我们将有可能确定新的治疗策略，不仅治疗，而且预防， RP后的艾德。

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.