Fatty Acid Amide Hydrolase Inhibitor Treatment in Men With Chronic Prostatitis/Chronic Pelvic Pain Syndrome: An Adaptive Double-blind, Randomized Controlled Trial

Objective To examine the effect of a peripherally active fatty acid amide hydrolase (FAAH) inhibitor ASP3652 on safety and efficacy outcomes in chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). Inhibition of FAAH is hypothesized to reduce the excitability of urinary tract afferents including nociceptors. Materials and Methods In this adaptive, randomized, double-blind, placebo-controlled study, adult male patients with moderate to severe CP/CPPS were treated for 12 weeks with an oral dose of ASP3652 (25, 75, 150, or 300 mg twice daily, or 300 mg once daily), or placebo. A Bayesian model was used for adaptive prospective modeling of randomization, study continuation decisions, and analysis of the efficacy variables. Results The study was stopped for futility at preplanned interim analysis when 239 patients were randomized (226 were included in the intention-to-treat set): the 25 mg group showed the largest reduction of the primary end point National Institutes of Health Chronic Prostatitis Symptom Index total score (7.0 points), but the placebo group showed a mean reduction of 7.3 points (difference: 0.3 [95% confidence interval: −1.9, 2.6]). Micturition outcomes improved compared with placebo in all ASP3652 groups; for example, in the 300 mg twice daily group, voiding frequency decreased by −1.10 (95% CI: −2.0, −0.2) voids/24 hours vs placebo. Safety outcomes were comparable across the treatment groups. Conclusion ASP3652 was generally safe and well-tolerated. It did not show efficacy on pain symptoms in patients with CP/CPPS. However, the results indicate that FAAH inhibition may attenuate lower urinary tract symptoms. Dedicated studies in patients with lower urinary tract dysfunction are needed to confirm this

Lipid Domain Structure of the Plasma Membrane Revealed by Patching of Membrane Components

Lateral assemblies of glycolipids and cholesterol, “rafts,” have been implicated to play a role in cellular processes like membrane sorting, signal transduction, and cell adhesion. We studied the structure of raft domains in the plasma membrane of non-polarized cells. Overexpressed plasma membrane markers were evenly distributed in the plasma membrane. We compared the patching behavior of pairs of raft markers (defined by insolubility in Triton X-100) with pairs of raft/non-raft markers. For this purpose we cross-linked glycosyl-phosphatidylinositol (GPI)-anchored proteins placental alkaline phosphatase (PLAP), Thy-1, influenza virus hemagglutinin (HA), and the raft lipid ganglioside GM1 using antibodies and/or cholera toxin. The patches of these raft markers overlapped extensively in BHK cells as well as in Jurkat T–lymphoma cells. Importantly, patches of GPI-anchored PLAP accumulated src-like protein tyrosine kinase fyn, which is thought to be anchored in the cytoplasmic leaflet of raft domains. In contrast patched raft components and patches of transferrin receptor as a non-raft marker were sharply separated. Taken together, our data strongly suggest that coalescence of cross-linked raft elements is mediated by their common lipid environments, whereas separation of raft and non-raft patches is caused by the immiscibility of different lipid phases. This view is supported by the finding that cholesterol depletion abrogated segregation. Our results are consistent with the view that raft domains in the plasma membrane of non-polarized cells are normally small and highly dispersed but that raft size can be modulated by oligomerization of raft components

Plasma Membrane Microdomains Act as Concentration Platforms to Facilitate Intoxication by Aerolysin

It has been proposed that the plasma membrane of many cell types contains cholesterol-sphingolipid–rich microdomains. Here, we analyze the role of these microdomains in promoting oligomerization of the bacterial pore-forming toxin aerolysin. Aeroly-sin binds to cells, via glycosyl phosphatidylinositol- anchored receptors, as a hydrophilic soluble protein that must polymerize into an amphipathic ring-like complex to form a pore. We first show that oligomerization can occur at >105-fold lower toxin concentration at the surface of living cells than in solution. Our observations indicate that it is not merely the number of receptors on the target cell that is important for toxin sensitivity, but their ability to associate transiently with detergent resistant microdomains. Oligomerization appears to be promoted by the fact that the toxin bound to its glycosyl phosphatidylinositol-anchored receptors, can be recruited into these microdomains, which act as concentration devices

Apical and basolateral transferrin receptors in polarized BeWo cells recycle through separate endosomes

Contrary to most other epithelia, trophoblasts in the human placenta, which form the physical barrier between the fetal and the maternal blood circulation, express high numbers of transferrin receptors on their apical cell surface. This study describes the establishment of a polarized trophoblast-like cell line BeWo, which exhibit a high expression of transferrin receptors on the apex of the cells. Cultured on permeable filter supports, BeWo cells formed a polarized monolayer with microvilli on their apical cell surface. Across the monolayer a transepithelial resistance developed of approximately 600 omega.cm2 within 4 d. Depletion of Ca2+ from the medium decreased the resistance to background levels, showing its dependence on the integrity of tight junctions. Within the same period of time the secretion of proteins became polarized. In addition, the compositions of integral membrane proteins at the apical and basolateral plasma membrane domains were distinct as determined by domain-selective iodination. Similar to placental trophoblasts, binding of 125I-labeled transferrin to BeWo monolayers revealed that the transferrin receptor was expressed at both plasma membrane domains. Apical and basolateral transferrin receptors were found in a 1:2 surface ratio and exhibited identical dissociation constants and molecular weights. After uptake, transferrin recycled predominantly to the domain of administration, indicating separate recycling pathways from the apical and basolateral domain. This was confirmed by using diaminobenzidine cytochemistry, a technique by which colocalization of endocytosed 125I-labeled and HRP-conjugated transferrin can be monitored. No mixing of the two types of ligands was observed, when both ligands were simultaneously internalized for 10 or 60 min from opposite domains, demonstrating that BeWo cells possess separate populations of apical and basolateral early endosomes. In conclusion, the trophoblast-like BeWo cell line can serve as a unique model to compare the apical and basolateral endocytic pathways of a single ligand, transferrin, in polarized epithelial cell

Bidirectional transcytosis determines the steady state distribution of the transferrin receptor at opposite plasma membrane domains of BeWo cells

Trophoblast-like BeWo cells form well-polarized epithelial monolayers, when cultured on permeable supports. Contrary to other polarized cell systems, in which the transferrin receptor is found predominantly on the basolateral cell surface, BeWo cells express the transferrin receptor at both apical and basolateral cell surfaces (Cerneus, D.P., and A. van der Ende. 1991. J. Cell Biol. 114: 1149-1158). In the present study we have addressed the question whether BeWo cells use a different sorting mechanism to target transferrin receptors to the cell surface, by examining the biosynthetic and transcytotic pathways of the transferrin receptor in BeWo cells. Using trypsin and antibodies to detect transferrin receptors at the cell surface of filter-grown BeWo cells, we show that at least 80% of newly synthesized transferrin receptor follows a direct pathway to the basolateral surface, demonstrating that the transferrin receptor is efficiently intracellularly sorted. After surface arrival, pulse-labeled transferrin receptor equilibrates between apical and basolateral cell surfaces, due to ongoing transcytotic transport in both directions. The subsequent redistribution takes over 120 min and results in a steady state distribution with 1.5-2.0 times more transferrin receptors at the basolateral surface than at the apical surface. By monitoring the fate of surface-bound 125I-transferrin, internalized either from the apical or basolateral surface transcytosis of the transferrin receptor was studied. About 15% of 125I-transferrin is transcytosed in the basolateral to apical direction, whereas 25% is transcytosed in the opposite direction, indicated that the fraction of receptors involved in transcytosis is roughly twofold higher for the apical receptor pool, as compared to the basolateral pool. Upon internalization, both apical and basolateral receptor pools become redistributed on both surfaces, resulting in a twofold higher number of transferrin receptors at the basolateral surface. Our results indicate that in BeWo cells bidirectional transcytosis is the main factor in surface distribution of transferrin receptors on apical and basolateral surfaces, which may represent a cell type-specific, post-endocytic, sorting mechanis

Detergent insolubility of alkaline phosphatase during biosynthetic transport and endocytosis. Role of cholesterol

Alkaline phosphatase is anchored to the outer leaflet of the plasma membrane by a covalently attached glycosyl-phosphatidylinositol anchor. We have studied the biosynthetic transport and endocytosis of alkaline phosphatase in the choriocarcinoma cell line BeWo, which endogenously expresses this protein. It was demonstrated that the protein was synthesized as a Triton X-100-soluble precursor. During transport to the cell surface the enzyme was converted in a mature form, which was insoluble in Triton X-100 at 0 degrees C. Once at the cell surface 85% of alkaline phosphatase remained in the detergent-insoluble form. Under steady state conditions 15% of alkaline phosphatase was endocytosed. Most interestingly, this fraction of internalized alkaline phosphatase was completely soluble in Triton X-100 at 0 degrees C. After depletion of membrane cholesterol by saponin, alkaline phosphatase became completely soluble in Triton X-100 at 0 degrees C, suggesting that cholesterol plays a critical role in the formation and maintenance of Triton X-100-resistant membrane domain