Penile erection is a neurovascular phenomenon, and erectile dysfunction (ED) is caused mainly by vascular risk factors or diseases, neurologic abnormalities, and hormonal disturbances. Men with diabetic ED often have severe endothelial dysfunction and peripheral nerve damage, which result in poor response to oral phosphodiesterase-5 inhibitors. Nerve injury-induced protein 1 (Ninjurin 1, Ninj1) is known to be involved in neuroinflammatory processes and to be related to vascular regression during the embryonic period. Here, we demonstrate in streptozotocin-induced diabetic mice that inhibition of the Ninj1 pathway by administering Ninj1-neutralizing antibody (Ninj1-Ab) or by using Ninj1-knockout mice successfully restored erectile function through enhanced penile angiogenesis and neural regeneration. Angiopoietin-1 (Ang1) expression was down-regulated and angiopoietin-2 expression was up-regulated in the diabetic penis compared with that in controls, and these changes were reversed by treatment with Ninj1-Ab. Ninj1 blockade-mediated penile angiogenesis and neural regeneration as well as recovery of erectile function were abolished by inhibition of Ang1-Tie2 (tyrosine kinase with Ig and epidermal growth factor homology domain-2) signaling with soluble Tie2 antibody or Ang1 siRNA. The present results suggest that inhibition of the Ninj1 pathway will be a novel therapeutic strategy for treating ED.diabetes mellitus | male sexual dysfunction | peripheral neuropathy E rectile dysfunction (ED), which is defined as an inability to attain or maintain penile erection sufficient for satisfactory sexual intercourse (1), is caused by a variety of pathologic conditions including vascular risk factors or diseases, neurologic abnormalities, and hormonal disturbances (2, 3). Diabetes mellitus is one of the most common causes of ED, and about 50-75% of male diabetic patients have ED (4, 5). Multiple pathogenetic factors, such as endothelial dysfunction, atherosclerosis, autonomic neuropathy, inflammation, fibrosis, and hypogonadism, are involved in diabetic ED (4-6). The multiple factors causing diabetic ED contribute to reduced responsiveness to currently available oral phosphodiesterase-5 (PDE5) inhibitors, which enhance the nitric oxide (NO)-cGMP pathway by inhibiting the breakdown of cGMP (7). The severity of endothelial dysfunction and peripheral neuropathy are mainly responsible for the poor responsiveness of diabetic patients to PDE5 inhibitors (8, 9). Because the effects of PDE5 inhibitors depend on endogenous NO formation, PDE5 inhibitors fail to increase the cGMP level above the threshold required for penile erection if bioavailable NO is insufficient as the result of severe endothelial dysfunction or peripheral neuropathy (9). Therefore, a new treatment strategy that corrects both endothelial dysfunction and peripheral neuropathy is required for men with diabetic ED.A variety of strategies targeting therapeutic angiogenesis and neural regeneration have been introduced to restore erectile function at the preclinical lev...

BackgroundAccidental mandibular nerve injury may occur during tooth extraction or implant procedures, causing ectopic orofacial pain. The exact mechanisms underlying ectopic orofacial pain following mandibular nerve injury is still unknown. Here, we investigated the role of macrophages and tumor necrosis factor alpha (TNFα) in the trigeminal ganglion (TG) in ectopic orofacial pain following inferior alveolar nerve transection (IANX).MethodsIANX was performed and the mechanical head-withdrawal threshold (MHWT) in the whisker pad skin ipsilateral to IANX was measured for 15 days. Expression of Iba1 in the TG was examined on day 3 after IANX, and the MHWT in the whisker pad skin ipsilateral to IANX was measured following successive intra-ganglion administration of the macrophage depletion agent liposomal clodronate Clophosome-A (LCCA). TNFα expression in the TG and the MHWT in the whisker pad skin ipsilateral to IANX following successive intra-ganglion administration of the TNFα blocker etanercept were measured on day 3 after IANX, and tumor necrosis factor receptor-1 (TNFR1) immunoreactive (IR) cells in the TG were analyzed immunohistochemically on day 3.ResultsThe MHWT in the whisker pad skin was significantly decreased for 15 days, and the number of Iba1-IR cells was significantly increased in the TG on day 3 after IANX. Successive intra-ganglion administration of the macrophage depletion agent LCCA significantly reduced the increased number of Iba1-IR cells in the TG and reversed the IANX-induced decrease in MHWT in the whisker pad skin. TNFα expression was increased in the TG on day 3 after IANX and was reduced following successive intra-ganglion administration of the TNFα inhibitor etanercept. The decreased MHWT was also recovered by etanercept administration, and TNFR1-IR cells in the TG were increased on day 3 following IANX.ConclusionsThese findings suggest that signaling cascades resulting from the production of TNFα by infiltrated macrophages in the TG contributes to the development of ectopic mechanical allodynia in whisker pad skin following IANX.

Epigenetic modifications, such as histone acetylation/deacetylation, have been shown to play a role in the pathogenesis of fibrotic disease. Peyronie's disease (PD) is a localized fibrotic process of the tunica albuginea, which leads to penile deformity. This study was undertaken to determine the anti-fibrotic effect of small interfering RNA (siRNA)-mediated silencing of histone deacetylase 2 (HDAC2) in primary fibroblasts derived from human PD plaque. PD fibroblasts were pre-treated with HDAC2 siRNA and then stimulated with transforming growth factor-b1 (TGF-b1). Protein was extracted from treated fibroblasts for Western blotting and the membranes were probed with antibody to phospho-Smad2/Smad2, phospho-Smad3/Smad3, smooth muscle a-actin and extracellular matrix proteins, including plasminogen activator inhibitor-1, fibronectin, collagen I and collagen IV. We also performed immunocytochemistry to detect the expression of extracellular matrix proteins and to examine the effect of HDAC2 siRNA on the TGF-b1-induced nuclear translocation of Smad2/3 in fibroblasts. Knockdown of HDAC2 in PD fibroblasts abrogated TGF-b1-induced extracellular matrix production by blocking TGF-b1-induced phosphorylation and nuclear translocation of Smad2 and Smad3, and by inhibiting TGF-b1-induced transdifferentiation of fibroblasts into myofibroblasts. Decoding the individual function of the HDAC isoforms by use of siRNA technology, preferably siRNA for HDAC2, may lead to the development of specific and safe epigenetic therapies for PD.

Introduction Radical prostatectomy for prostate cancer can not only induce cavernous nerve injury (CNI) but also result in structural changes in the cavernous tissues. Nerve injuryinduced protein 1, Ninjurin1 (Ninj1), is known to be involved in neuroinflammatory processes and to be related to vascular regression during the embryonic period. Aim The study aims to determine whether and how Ninj1 neutralizing antibody (Ninj1Ab) restores erectile function in mice with CNI. Methods Twelveweekold C57BL/6J mice were used and distributed into four groups: sham operation group and CNI groups receiving a single intracavernous injection of immunoglobulin G (IgG) control antibody, lowdose Ninj1Ab (1.0 μg/20 μL), or highdose Ninj1Ab (2.5 μg/20 μL). Main Outcome Measures One week after bilateral cavernous nerve crush, erectile function was measured by electrical stimulation of the cavernous nerve. The penis was harvested for histologic examinations and Western blot analysis. Results The cavernous expression of Ninj1 protein was upregulated up to 7 days after CNI and returned to baseline levels thereafter. Local delivery of Ninj1Ab significantly increased penile neuronal nitric oxide synthase and neurofilament contents, induced cavernous endothelial proliferation and phosphorylation of Akt and endothelial nitric oxide synthase, and decreased endothelial cell apoptosis in the CNI mice by upregulating angiopoietin1 and downregulating angiopoietin2. Highdose Ninj1Ab induced profound restoration of erectile function in the CNI mice (91% of sham control values), whereas lowdose Ninj1Ab elicited partial improvement. Conclusion The dual neurotrophic and angiogenic effects of Ninj1 blockade may provide a good opportunity for treating erectile dysfunction resulting from radical prostatectomy.

ObjectivesTo examine the therapeutic effect of adenovirus encoding histone deacetylase 2 (HDAC2) small hairpin RNA (Ad-HDAC2 shRNA) in a rat model of Peyronie's disease (PD) and to determine the mechanisms by which HDAC2 knockdown ameliorates fibrotic responses in primary fibroblasts derived from human PD plaque. Materials and MethodsRats were distributed into four groups (n = 6 per group): age-matched controls without treatment; rats in which PD has been induced (PD rats) without treatment; PD rats receiving a single injection of control adenovirus encoding scrambled small hairpin RNA (Ad-shRNA) (day 15; 1 × 10 8 pfu/0.1 mL phosphate-buffered saline [PBS]); and PD rats receiving a single injection of Ad-HDAC2 shRNA (day 15; 1 × 10 8 pfu/0.1 mL PBS) into the lesion. PD-like plaque was induced by repeated intratunical injections of 100 μL each of human fibrin and thrombin solutions on days 0 and 5. On day 30, the penis was harvested for histological examination. Fibroblasts isolated from human PD plaque were pretreated with HDAC2 small interfering (si)RNA (100 pmoL) and then stimulated with transforming growth factor (TGF)-β1 (10 ng/mL) to determine hydroxyproline levels, procollagen mRNA, apoptosis and protein expression of poly(ADP-ribose) polymerase 1 (PARP1) and cyclin D1. ResultsWe observed that Ad-HDAC2 shRNA decreased inflammatory cell infiltration, reduced transnuclear expression of phospho-Smad3 and regressed fibrotic plaque of the tunica albuginea in PD rats in vivo. siRNA-mediated silencing of HDAC2 significantly decreased the TGF-β1-induced transdifferentiation of fibroblasts into myofibroblasts and collagen production, and induced apoptosis by downregulating the expression of PARP1, and decreased the expression of cyclin D1 (a positive cell-cycle regulator) in primary cultured fibroblasts derived from human PD plaque in vitro. ConclusionSpecific inhibition of HDAC2 with RNA interference may represent a novel targeted therapy for PD.