Sonic hedgehog, a regulator of CN injury induced apoptosis

描述（由申请人提供）：勃起功能障碍（ED）影响了52%的40至70岁男性。30-87%的前列腺癌患者行前列腺切除术后出现ED，而PDE5抑制剂在29-86%的前列腺切除术后出现ED的患者中无效，这取决于患者的神经损伤状况。在这一人群中治疗效果的降低使得新的治疗方法治疗ED至关重要。在动物模型和人类ED患者中，阴茎平滑肌细胞凋亡明显增加。我们认为，当CN被切断时，阴茎平滑肌细胞大量凋亡是ED发生的主要因素。如果能在CN再生的同时防止前列腺切除术后的细胞凋亡，则可以更快地恢复正常勃起功能，防止引起ED的不可逆的阴茎形态变化。了解调节阴茎平滑肌凋亡的机制对于开发治疗和预防ED的新治疗方法至关重要。SHH是阴茎平滑肌的重要调节因子。当SHH在阴茎中被抑制时，平滑肌细胞凋亡增加12倍，导致ED。SHH蛋白治疗能够抑制CN损伤诱导的细胞凋亡，这表明SHH具有通过抑制平滑肌细胞凋亡来预防ED的巨大潜力。在这些研究中使用的Affi-Gel球技术并不适用于人类，因此我们建议开发纳米颗粒将SHH蛋白递送到阴茎，并假设通过纳米颗粒递送SHH将有效抑制CN损伤诱导的细胞凋亡。这项新技术有很大的潜力发展成为一种预防前列腺切除术时患者细胞凋亡的治疗方法，因此具有重要的临床意义。关于SHH自身在阴茎中的调节机制以及SHH蛋白减少如何诱导细胞凋亡的机制尚不清楚。可能是神经输入/完整性调节了阴茎中的SHH，因为在两种神经病变模型中，CN损伤大鼠和BB/WOR糖尿病大鼠中SHH蛋白显著降低。由于SHH蛋白在糖尿病人阴茎中的减少与在大鼠中的观察平行，这对SHH蛋白减少如何诱导阴茎细胞凋亡具有临床意义。我们的研究结果表明，在CN损伤后，HIP会与PTCH1竞争SHH结合。因此，我们假设神经输入的缺失通过PTCH1和HIP依赖机制减少了阴茎中的SHH蛋白并诱导了阴茎平滑肌的凋亡。公共卫生相关性：勃起功能障碍（ED）是一种重要的医学状况，目前的治疗方案对糖尿病患者和前列腺切除术治疗的前列腺癌患者无效。Sonic hedgehog基因（SHH）是阴茎平滑肌的重要调节因子，具有通过抑制平滑肌细胞凋亡来预防ED的巨大潜力。我们建议开发SHH蛋白的纳米颗粒递送作为一种治疗方法，以防止前列腺切除术时患者的细胞凋亡。关于SHH自身在阴茎中的调节机制以及SHH蛋白减少如何诱导细胞凋亡的机制尚不清楚，将在本提案中进行深入研究。

DESCRIPTION (provided by applicant): Erectile dysfunction (ED) affects 52% of men between the ages of 40 and 70. 30-87% of prostate cancer patients treated by prostatectomy experience ED and PDE5 inhibitors are ineffective in 29-86% of prostatectomy patients who experience ED, depending on their nerve injury status. The reduced efficacy of treatments in this population makes novel therapeutic approaches to treat ED essential. Significantly increased apoptosis of penile smooth muscle is common in both animal models and human patients with ED. We propose that abundant apoptosis observed in penile smooth muscle when the CN is cut is a major contributing factor to ED development. If apoptosis could be prevented following prostatectomy while the CN regenerates, then resumption of normal erectile function would occur more quickly, and irreversible morphology changes in the penis that cause ED would be prevented. Understanding the mechanisms that regulate smooth muscle apoptosis in the penis is critical for development of new therapeutic approaches for ED treatment and prevention. Sonic hedgehog (SHH) is an essential regulator of penile smooth muscle. When SHH is inhibited in the penis, there is a 12-fold increase in smooth muscle apoptosis that results in ED. SHH protein treatment is able to suppress CN injury induced apoptosis, indicating that SHH has significant potential to be developed as a treatment to prevent ED by suppressing smooth muscle apoptosis. The Affi-Gel bead technology used in these studies is not applicable to humans, so we propose to develop nanoparticle delivery of SHH protein to the penis and hypothesize that SHH delivery via nanoparticles will be effective in suppressing apoptosis induction caused by CN injury. This novel technology has substantial potential to be developed into a therapy to prevent apoptosis in patients at the time of prostatectomy, so has significant clinical relevance. The mechanism of how SHH itself is regulated in the penis and how decreased SHH protein induces apoptosis is poorly understood. It is likely that neural input/integrity regulates SHH in the penis since SHH protein is significantly decreased in two models of neuropathy, the CN injured rat and in the BB/WOR diabetic rat. Since SHH protein is decreased in diabetic human penes in parallel with observations in the rat, this lends clinical significance to how decreased SHH protein can induce apoptosis in the penis. Our results suggest that HIP out competes PTCH1 for SHH binding after CN injury. Thus we hypothesize that loss of neural input decreases SHH protein in the penis and induces apoptosis in penile smooth muscle through a PTCH1 and HIP dependent mechanism. PUBLIC HEALTH RELEVANCE: Erectile dysfunction (ED) is a significant medical condition and current treatment options are ineffective in diabetic patients and in prostate cancer patients treated by prostatectomy. Sonic hedgehog (SHH) is an essential regulator of penile smooth muscle that has significant potential to be developed as a treatment to prevent ED by suppressing smooth muscle apoptosis. We propose to develop nanoparticle delivery of SHH protein as a therapy to prevent apoptosis in patients at the time of prostatectomy. The mechanism of how SHH itself is regulated in the penis and how decreased SHH protein induces apoptosis is poorly understood and will be examined in depth in this proposal.