Cystathionine gamma-lyase is required for the heat shock protein 70-driven penile neurovascular regeneration and erectile function recovery

Neurovascular dysfunction in penis is a fundamental reason of erectile dysfunction. Diabetes mellitus is one of the major causes of erectile dysfunction and leads to a poor response to oral phosphodiesterase-5 inhibitors. Heat shock protein 70 (Hsp70), a ubiquitous molecular chaperone exist in all living organisms, is known to play a role in cell survival and neuroprotection. Here, we report an effectiveness of Hsp70 in mediating neurovascular regeneration in diabetic conditions. Using Hsp70-Tg mice or Hsp70 protein administration, we demonstrate that overexpression of Hsp70 in diabetic mice restores erectile function through enhanced penile angiogenesis and neural regeneration. We found that cystathionine gamma-lyase (Cse) is a novel target of Hsp70-driven penile angiogenesis and neural regeneration. Hsp70-Cse triggered SDF1/HO-1/PI3K/Akt/eNOS/NF-κB p65 pathways involved in angiogenesis and neural regeneration. Coimmunoprecipitation and His-Tag pull down assay using mouse cavernous endothelial cells treated with Hsp70 showed the physical interaction between Hsp70 and Cse, and solid-phase binding assay revealed a high-affinity Hsp70-Cse binding with an apparent dissociation constant of 1.8 nmol/L. We provide a novel and solid evidence for Cse-dependent mechanism of Hsp70, which mediates Hsp70-induced neurovascular regeneration and the restoration of erectile function under diabetic conditions. Control (normal glucose) (n=3), Hg (high glucose) (n=4) and Hspto (high glucose+Hsp70) (n=4)

阴茎神经血管功能障碍是勃起功能障碍的核心致病基础。糖尿病是勃起功能障碍的主要诱因之一，可导致患者对口服磷酸二酯酶5抑制剂的临床应答不佳。热休克蛋白70（Heat shock protein 70, Hsp70）是广泛存在于所有生物体内的泛在分子伴侣，已知其在细胞存活与神经保护中发挥重要调控作用。本研究报道了Hsp70在糖尿病状态下介导神经血管再生的有效性。通过使用Hsp70转基因（Hsp70-Tg）小鼠或外源性给予Hsp70蛋白处理，我们证实糖尿病小鼠体内Hsp70过表达可通过增强阴茎血管生成与神经再生，恢复勃起功能。我们发现，胱硫醚γ裂解酶（cystathionine gamma-lyase, Cse）是Hsp70驱动的阴茎血管生成与神经再生的新型靶点。Hsp70与Cse的相互作用可激活SDF1/HO-1/PI3K/Akt/eNOS/NF-κB p65信号通路，参与血管生成与神经再生过程。通过对经Hsp70处理的小鼠海绵体内皮细胞开展免疫共沉淀与His标签下拉实验，证实了Hsp70与Cse之间存在物理相互作用；固相结合实验结果显示，二者具有高亲和力结合，表观解离常数为1.8 nmol/L。本研究为Hsp70依赖Cse的作用机制提供了全新且确凿的实验证据，该机制可介导糖尿病状态下Hsp70诱导的神经血管再生与勃起功能恢复。本研究设置三组实验：正常葡萄糖对照组（n=3）、高葡萄糖组（Hg，n=4）以及高葡萄糖+Hsp70组（Hspto，n=4）