[Experimental rodent models of chronic prostatitis: effect of phosphodiesterase 5 inhibitor on chronic pelvic-pain-related behavior].

Chronic prostatitis / chronic pelvic pain syndrome (CP/CPPS) is commonly diagnosed in men younger than 50 years old. It is characterized by pelvic pain, voiding symptoms and sexual dysfunction. The considerable discomfort or pain experienced has a negative impact on the quality of life of patients and is a huge economic burden because of the high recurrence rate and the low cure rate. Appropriate animal models are essential for the development of new drugs for the treatment of CP/CPPS, and several rodent models induced by different methods and over different time frames have been established. This article reviews studies of three in vivo rodent models of prostatitis, namely, chemical-induced, autoimmune-induced and hormone-associated models reported by us and other investigators. Recent clinical investigation has suggested that tadalafil improves the International Prostatic Symptom Score and the total National Institutes of Health Chronic Prostatitis Symptom Index score of patients with benign prostatic hyperplasia with CP/CPPS, which enables us to investigate the effect of tadalafil on the pelvic-pain-related behavior and prostatic inflammation in two of these prostatitis model types, experimental autoimmune prostatitis (EAP) and hormone/castration-induced prostatitis (HCP). Both models showed the pelvic-pain-related behavior and prostatic inflammation that are characteristic of chronic prostatitis. In EAP, tadalafil suppressed both the pelvic-pain-related behavior and the prostatic inflammation. In HCP, tadalafil suppressed the pelvic-pain-related behavior. These results mimic the clinical findings. Therefore EAP and HCP are suitable for the evaluation of the potency of drugs for the treatment of CP/CPPS.

Role of Atg8 in the regulation of vacuolar membrane invagination.

Cellular heat stress can cause damage, and significant changes, to a variety of cellular structures. When exposed to chronically high temperatures, yeast cells invaginate vacuolar membranes. In this study, we found that the expression of Atg8, an essential autophagy factor, is induced after chronic heat stress. In addition, without Atg8, vacuolar invaginations are induced conspicuously, beginning earlier and invaginating vacuoles more frequently after heat stress. Our results indicate that Atg8's invagination-suppressing functions do not require Atg8 lipidation, in contrast with autophagy, which requires Atg8 lipidation. Genetic analyses of vps24 and vps23 further suggest that full ESCRT machinery is necessary to form vacuolar invaginations irrespective of Atg8. In contrast, through a combined mutation with the vacuole BAR domain protein Ivy1, vacuoles show constitutively enhanced invaginated structures. Finally, we found that the atg8Δivy1Δ mutant is sensitive against agents targeting functions of the vacuole and/or plasma membrane (cell wall). Collectively, our findings revealed that Atg8 maintains vacuolar membrane homeostasis in an autophagy-independent function by coordinating with other cellular factors.

Voiding behavior and chronic pelvic pain in two types of rat nonbacterial prostatitis models: Attenuation of chronic pelvic pain by repeated administration of tadalafil.

BACKGROUND: Experimental autoimmune prostatitis (EAP) and prostatitis induced by 17ß-estradiol treatment combined with castration (hormone/castration-induced prostatitis; HCP) are the most commonly used rodent models of nonbacterial prostatitis. We studied the effect of the phosphodiesterase 5 inhibitor tadalafil on chronic pelvic pain in two such models in rats. METHODS: EAP was induced by intradermal injection of rat prostate antigen and complete Freund's adjuvant on Days 0 and 28. HCP was induced by castration followed by daily subcutaneous injection of 17ß-estradiol for 30 days. On Day 42 after antigen injection in the EAP model and Day 30 after castration in the HCP model, we investigated voiding behavior, pelvic pain (measured by applying von Frey filaments to the lower abdomen), and inflammatory changes, including changes in histopathology and IL-1ß, CCL2, and CCL3 mRNA levels. We investigated the effect of repeated administration of tadalafil on chronic pelvic pain in both models. RESULTS: In the EAP model, we observed inflammation in the ventral prostate, while in the HCP model, we observed inflammation in the lateral lobe of the prostate. Neither model showed any change in voiding behavior. As well as in the EAP model, in which chronic pelvic pain was observed, we found for the first time that HCP led to a significant increase in chronic pelvic pain. Repeated treatment with tadalafil attenuated the chronic pelvic pain in both models. CONCLUSIONS: Chronic pelvic pain was induced in both EAP and HCP models. Tadalafil significantly attenuated the chronic pelvic pain in both models.

Chronic pelvic pain and prostate inflammation in rat experimental autoimmune prostatitis: Effect of a single treatment with phosphodiesterase 5 inhibitors on chronic pelvic pain.

BACKGROUND: Experimental autoimmune prostatitis (EAP) is most often used as a nonbacterial model of chronic prostatitis/chronic pelvic pain. We investigated the development of chronic pelvic pain and inflammatory changes in rat EAP and examined the effect of a single treatment with phosphodiesterase 5 (PDE5) inhibitors on the chronic pelvic pain. METHODS: EAP was induced in rats by intradermal injection of rat prostate antigen and complete Freund's adjuvant on days 0 and 28. On day 42, after antigen injection, prostatic inflammatory changes, including the mRNA and protein levels of cytokines/chemokines, were measured and histological analysis of the prostate was performed. Pelvic pain was measured by applying von Frey filaments to the lower abdomen. To confirm that this model is appropriate for evaluating pelvic pain, we tested two drugs, celecoxib and pregabalin, which are clinically used for the treatment of prostatitis-related pain. Subsequently, we examined the effects of single treatments with three phosphodiesterase 5 inhibitors, including tadalafil, on pelvic pain in this model. RESULTS: On day 42, after antigen injection, the mRNA levels of 44 of 84 kinds of cytokines/chemokines and their receptors increased significantly in EAP rats, as did the protein levels of seven of 23 kinds of cytokines/chemokines. Histological analysis revealed inflammation characterized by neutrophils and/or mononuclear cells in the glandular and stromal tissue of the ventral prostate from rats in the EAP group. Some animals in this group showed fibrosis and hemorrhage in the stromal tissue. Pelvic pain had developed in EAP rats, which was attenuated by a single treatment with celecoxib or pregabalin, suggesting that EAP is an appropriate model for prostatitis-related pain. A single treatment with any of the three PDE5 inhibitors tested attenuated the chronic pelvic pain. CONCLUSIONS: Prostatitis leads to inflammatory changes in the prostate, which may contribute to the development and maintenance of chronic pelvic pain. PDE5 inhibitors, including tadalafil, may have the ability to block chronic pelvic pain.

Effect of tadalafil on chronic pelvic pain and prostatic inflammation in a rat model of experimental autoimmune prostatitis.

BACKGROUND: Experimental autoimmune prostatitis (EAP) shares important clinical features with clinical chronic prostatitis/chronic pelvic pain. We investigated the effect of tadalafil on pelvic pain and prostatic inflammation in a rat EAP model. METHODS: EAP was induced in rats by intradermal injection of rat prostate antigen and complete Freund's adjuvant on days 0 and 28. Rats were treated with tadalafil (2 mg/kg, p.o.; EAP-tadalafil) or vehicle (EAP-vehicle) once daily from day 0, while sham-operated animals were treated with vehicle only (Sham). Tactile allodynia was measured on days 28, 35, and 42 by applying von Frey filaments to the lower abdomen as an index of pelvic pain. On day 42, the plasma immunoglobulin G (IgG) concentration and the testosterone/estradiol ratio were measured and histopathological analysis of the prostate was performed. RESULTS: Tactile allodynia in the pelvic region was observed on days 28, 35, and 42 after EAP induction. The tactile allodynia observed on day 42 was significantly reduced by repeated treatment with tadalafil. Plasma IgG concentrations increased after EAP induction but the increase was not changed by tadalafil treatment. Prostate tissues were characterized by epithelial necrosis, infiltration of neutrophils and/or lymphocytes to acini and stroma, and fibrosis, in addition to a high stroma-to-epithelium ratio. Tadalafil treatment significantly suppressed the severity of the lesions. CONCLUSIONS: EAP rats developed pelvic pain, prostatic inflammation and increased plasma IgG concentrations. Tadalafil inhibited the chronic pelvic pain and prostatic inflammation, suggesting that its anti-inflammatory action may contribute to its blocking of pain development in the EAP model.

Identification of the role of bone morphogenetic protein (BMP) and transforming growth factor-ß (TGF-ß) signaling in the trajectory of serotonergic differentiation in a rapid assay in mouse embryonic stem cells in vitro.

The mechanism by which extracellular molecules control serotonergic cell fate remains elusive. Recently, we showed that noggin, which inactivates bone morphogenetic proteins (BMPs), induces serotonergic differentiation of mouse embryonic (ES) and induced pluripotent stem cells with coordinated gene expression along the serotonergic lineage. Here, we created a rapid assay for serotonergic induction by generating knock-in ES cells expressing a naturally secreted Gaussia luciferase driven by the enhancer of Pet-1/Fev, a landmark of serotonergic differentiation. Using these cells, we performed candidate-based screening and identified BMP type I receptor kinase inhibitors LDN-193189 and DMH1 as activators of luciferase. LDN-193189 induced ES cells to express the genes encoding Pet-1, tryptophan hydroxylase 2, and the serotonin transporter, and increased serotonin release without altering dopamine release. In contrast, TGF-ß receptor inhibitor SB-431542 selectively inhibited serotonergic differentiation, without changing overall neuronal differentiation. LDN-193189 inhibited expression of the BMP signaling target gene Id, and induced the TGF-ß target gene Lefty, whereas the opposite effect was observed with SB-431542. This study thus provides a new tool to investigate serotonergic differentiation and suggests that inhibition of BMP type I receptors and concomitant activation of TGF-ß receptor signaling are implicated in serotonergic differentiation. Candidate-based screening for serotonergic induction using a rapid assay in mouse embryonic stem cells revealed that the bone morphogenetic protein (BMP) type I receptor kinase inhibitors selectively induce serotonergic differentiation, whereas the TGF-ß receptor inhibitor SB-431542 inhibits the differentiation. These results suggest that inhibition of BMP type I receptors and concomitant activation of transforming growth factor-ß (TGF-ß) receptor signaling are involved in the early trajectory of serotonergic differentiation.