Associate Professor University of Illinois at Chicago
Introduction: Erectile dysfunction (ED) treatments are minimally effective in prostatectomy and diabetic patients due to injury to the cavernous nerve (CN). CN injury causes loss of innervation, apoptosis of smooth muscle, fibrosis in the penis and ED. When developing novel therapies, the goal is to prevent the apoptotic response and penile remodeling, to preserve erectile function. Our previous studies found Sonic hedgehog (SHH) is a key mediator of penile remodeling. Our objective was to use RNA seq and pathway analysis, to identify changes in gene expression and signaling pathways that are altered in response to CN injury and the effect of SHH treatment by peptide amphiphile (PA), in a rat prostatectomy model of ED. Methods: Corpora cavernosal (CC) tissue was obtained from Sprague Dawley rats (n=36) that underwent bilateral CN crush, CN crush plus SHH PA treatment of the penis, or sham surgery. Rats were sacrificed 1, 2 and 4 days after surgery. RNA was extracted using TRIzol, DNase treated, and purified by Qiagen mini kit. RNAseq analysis was performed, and directional pathway analysis was examined with Ingenuity. A 2-fold change with a q-value <0.05 was used as a threshold for differential expression. Results: mRNA representing 523 genes had significant differential expression in CN crushed CC tissue relative to sham. Ingenuity analysis predicted increased necrosis, and decreased actin cytoskeleton, acute phase response signaling, cell movement, angiogenesis, and myeloid cell movement activity. With SHH PA treatment at the time of CN injury, these changes were reversed or significantly diminished. In addition, SHH PA impacted known mediators of ED by reducing apoptosis, and increasing cell survival, cell viability, muscle cell proliferation, VEGF, p38 MAPK, and PI3K/AKT pathways. Conclusions: RNAseq and pathway analysis identified changes in gene expression and pathway signaling associated with CN injury in a rat prostatectomy model. Pathway analysis predicted increases in processes associated with cell death and a loss of functions necessary for maintenance of CC architecture. Most CN injury associated changes were reversed or greatly diminished with SHH PA treatment of the penis at the time of injury. The results support the significant potential of SHH PA as a preventative treatment for ED in prostatectomy patients. Signaling pathways identified with CN injury provide many new avenues for intervention independently and in combination with SHH PA treatment. SOURCE OF Funding: DK101536
