Temporal gene signature of myofibroblast transformation in Peyronie's disease: first insights into the molecular mechanisms of irreversibility.

BACKGROUND: Transformation of resident fibroblasts to profibrotic myofibroblasts in the tunica albuginea is a critical step in the pathophysiology of Peyronie's disease (PD). We have previously shown that myofibroblasts do not revert to the fibroblast phenotype and we suggested that there is a point of no return at 36 hours after induction of the transformation. However, the molecular mechanisms that drive this proposed irreversibility are not known. AIM: Identify molecular pathways that drive the irreversibility of myofibroblast transformation by analyzing the expression of the genes involved in the process in a temporal fashion. METHODS: Human primary fibroblasts obtained from tunica albuginea of patients with Peyronie's disease were transformed to myofibroblasts using transforming growth factor beta 1 (TGF-ß1). The mRNA of the cells was collected at 0, 24, 36, 48, and 72 hours after stimulation with TGF-ß1 and then analyzed using a Nanostring nCounter Fibrosis panel. The gene expression results were analyzed using Reactome pathway analysis database and ANNi, a deep learning-based inference algorithm based on a swarm approach. OUTCOMES: The study outcome was the time course of changes in gene expression during transformation of PD-derived fibroblasts to myofibroblasts. RESULTS: The temporal analysis of the gene expression revealed that the majority of the changes at the gene expression level happened within the first 24 hours and remained so throughout the 72-hour period. At 36 hours, significant changes were observed in genes involved in MAPK-Hedgehog signaling pathways. CLINICAL TRANSLATION: This study highlights the importance of early intervention in clinical management of PD and the future potential of new drugs targeting the point of no return. STRENGTHS AND LIMITATIONS: The use of human primary cells and confirmation of results with further RNA analysis are the strengths of this study. The study was limited to 760 genes rather than the whole transcriptome. CONCLUSION: This study is to our knowledge the first analysis of temporal gene expression associated with the regulation of the transformation of resident fibroblasts to profibrotic myofibroblasts in PD. Further research is warranted to investigate the role of the MAPK-Hedgehog signaling pathways in reversibility of PD.

Statins synergize with phosphodiesterase type 5 inhibitors but not with selective estrogen receptor modulators to prevent myofibroblast transformation in an in vitro model of Peyronie's disease.

BACKGROUND: Peyronie's disease (PD) is a fibrotic disorder characterized by plaque formation in the tunica albuginea (TA) of the penis, and we have previously shown that inhibition of transformation of TA-derived fibroblasts to myofibroblasts using a combination phosphodiesterase type 5 (PDE5) inhibitors and selective estrogen receptor modulators (SERMs) is effective in slowing the progression of early PD. AIM: The study sought to investigate whether combinations of statins with PDE5 inhibitors or SERMs would affect myofibroblast transformation in vitro. METHODS: Primary fibroblasts were isolated from TA of patients with PD and stimulated with transforming growth factor ß1 in the absence and presence of a range of concentrations of statins, PDE5 inhibitors, SERMs, and their combinations for 72 hours before quantifying α-smooth muscle actin using in-cell enzyme-linked immunosorbent assay. OUTCOMES: The prevention of transforming growth factor ß1-induced transformation of TA-derived fibroblasts to myofibroblasts was measured in vitro. RESULTS: Statins (simvastatin, lovastatin) inhibited myofibroblast transformation in a concentration-dependent manner with half maximal inhibitory concentration values of 0.77 ± 0.07 µM and 0.8 ± 0.13 µM, respectively. Simvastatin inhibited myofibroblast transformation in a synergistic fashion when combined with vardenafil (a PDE5 inhibitor; log alpha >0). Combination of tamoxifen (a SERM) and simvastatin did not show synergy (log alpha <0). When 3 drugs (simvastatin, vardenafil, and tamoxifen) were combined, the effect was not synergistic, but rather was additive. CLINICAL IMPLICATIONS: A combination of a statin with a PDE5 inhibitor might be useful in the clinic to slow the progression of the disease in patients with early PD; however, caution should be taken with such a combination because of the reported myopathy as a side effect. STRENGTHS AND LIMITATIONS: The use of primary human cells from patients with PD is a strength of this study. The mechanisms by which these drug classes exert synergy when used in combination was not investigated. CONCLUSION: This is the first demonstration of an antifibrotic synergy between statins and PDE5 inhibitors.

Phosphodiesterase Type 5 Inhibitors and Selective Estrogen Receptor Modulators Can Prevent But Not Reverse Myofibroblast Transformation in Peyronie's Disease.

BACKGROUND: Myofibroblast transformation is a key step in the pathogenesis of Peyronie's disease (PD). Phosphodiesterase type 5 inhibitors (PDE5is) and selective estrogen receptor modulators (SERMs) can prevent the formation of fibrosis in in vitro and in vivo models of PD. However, it is unknown whether these drugs can also reverse established fibrosis. AIM: To investigate whether PDE5is and SERMs can reverse transforming growth factor beta 1 (TGF-ß1)-induced myofibroblast transformation and determine the point of no return. METHODS: In-Cell enzyme-linked immunosorbent assay was used to quantify TGF-ß1-induced myofibroblast transformation of human primary fibroblasts isolated from tunica albuginea (TA) of patients undergoing surgery for treatment of PD. Extracellular matrix production and collagen contraction assays were used as secondary assays. Reverse transcription-quantitative polymerase chain reaction and In-Cell enzyme-linked immunosorbent assay were used to measure drug target expression. PDE5i (vardenafil) and SERM (tamoxifen) were applied at various time points after TGF-ß1. OUTCOMES: Reversibility of myofibroblast transformation and drug target expression were investigated in a time-dependent manner in TA-derived fibroblasts. RESULTS: Vardenafil or tamoxifen could not reverse the myofibroblast traits of alpha-smooth muscle actin expression and extracellular matrix production, whereas only tamoxifen affected collagen contraction after 72 hours of TGF-ß1 treatment. Phosphodiesterase 5A and estrogen receptor (ER)-ß were downregulated after 72 hours, and estrogen receptor -α protein could not be quantified. Tamoxifen could prevent myofibroblast transformation until 36 hours after TGF-ß1 treatment, whereas vardenafil could prevent only 24 hours after TGF-ß1 treatment. This was mirrored by downregulation of drug targets on mRNA and protein level. Furthermore, antifibrotic signaling pathways, peroxisome proliferator-activated receptor gamma and betaglycan (TGFB receptor III), were significantly downregulated after 36 hours of TGF-ß1 exposure, as opposed to upregulation of profibrotic thrombospondin-1 at the same time point. CLINICAL TRANSLATION: This study suggests that using PDE5is and SERMs might only help for early-phase PD and further highlights the need to test drugs at the appropriate stage of the disease based on their mechanism of action. STRENGTHS & LIMITATIONS: The study uses primary human TA-derived fibroblasts that enhances translatability of the results. Limitations include that only 1 example of PDE5i- and SERM-type drug was tested. Time course experiments were only performed for marker expression experiments and not for functional assays. CONCLUSION: This is the first study to demonstrate that timing for administration of drugs affecting myofibroblast transformation appears to be vital in in vitro models of PD, where 36 hours of TGF-ß1 treatment can be suggested as a "point of no return" for myofibroblast transformation. Ilg MM, Stafford SJ, Mateus M, et al. Phosphodiesterase Type 5 Inhibitors and Selective Estrogen Receptor Modulators Can Prevent But Not Reverse Myofibroblast Transformation in Peyronie's Disease. J Sex Med 2020;17:1848-1864.

Simvastatin and the Rho-kinase inhibitor Y-27632 prevent myofibroblast transformation in Peyronie's disease-derived fibroblasts via inhibition of YAP/TAZ nuclear translocation.

OBJECTIVES: To uncover the anti-myofibroblast (MFB) properties of Rho-kinase inhibitor (compound Y-27632) and simvastatin in an in vitro model of Peyronie's disease (PD), a sexually debilitating disease caused by an irreversible fibrotic plaque in the penile tunica albuginea (TA). MATERIALS AND METHODS: Primary human fibroblasts (FBs) were isolated from surgically obtained TA tissue from patients with PD. To induce MFB status, cells were stimulated with 3 ng/mL transforming growth factor-ß1 (TGF-ß1). Increasing doses of Y-27632 and simvastatin were added. Real-time quantitative PCR was used to assess mRNA expression of α-smooth muscle actin (α-SMA), collagen III, elastin and connective tissue growth factor (CTGF) after 72 h. Western blot analysis was used to quantify α-SMA protein contents, and immunofluorescence (IF) was used to visualize MFB differentiation by staining for α-SMA after 72 h. A resazurin-based assay was used to assess cell viability to ensure the anti-MFB effect of the drugs. A mechanistic study was performed using IF staining for YAP/TAZ nuclear translocation. RESULTS: After 72 h of stimulation with TGF-ß1, a six- to 10-fold upregulation of α-SMA could be observed. When treated with Y-27632 or simvastatin, the α-SMA, collagen III, elastin and CTGF mRNA expression was impeded. Additionally, TGF-ß1 stimulation showed a twofold increase in α-SMA protein expression, which was reversed to non-stimulated levels after treatment with Y-27632 and simvastatin. Using IF, stimulated cells were identified as MFB (α-SMA+, Vim+) as opposed to the non-stimulated, Y-27632- and simvastatin-treated cells (α-SMA-, Vim+). The resazurin-based assay confirmed that the cell viability was not compromised by the administered drugs. On stimulation with TGF-ß1, nuclear translocation of YAP/TAZ could be observed, which was prevented by adding the aforementioned compounds. CONCLUSION: Transformation of FBs into the contractile and extracellular matrix-producing MFBs occurs after TGF-ß1 stimulation. In our experiments, Rho-kinase inhibition and simvastatin treatment were shown to prevent this in TGF-ß1-stimulated cells on an RNA and protein level through the inhibition of YAP/TAZ nuclear translocation. Y-27632 and simvastatin could become a novel treatment option in the early treatment of PD.

Understanding the Role of Adenosine Receptors in the Myofibroblast Transformation in Peyronie's Disease.

BACKGROUND: Peyronie's disease (PD) is a chronic fibrotic disease of the penis affecting a significant number of men worldwide without effective medical treatments. Myofibroblasts are pivotal in the pathogenesis of PD. Adenosine and adenosine receptors have been suggested to be involved in the pathophysiology of fibrosis. AIM: To understand the role of adenosine receptors in myofibroblast transformation in PD. METHODS: Fibroblasts were isolated from the non-PD tunica albuginea (TA) tissue and PD plaque tissue and were transformed into myofibroblasts using transforming growth factor (TGF)-ß1. Quantification of α-smooth muscle actin and adenosine receptors (adenosine receptor A1 [ADORA1], adenosine receptor A2A, adenosine receptor A2B [ADORA2B], and adenosine receptor A3) was performed using immuno-cytochemistry, in-cell enzyme-linked immuno-sorbent assay (ICE), and real-time reverse transcription quantitative polymerase chain reaction. The effect of various adenosine receptor agonists or antagonists on TGF-ß1-induced myofibroblast transformation was measured using ICE. OUTCOMES: Expression of adenosine receptors in myofibroblasts obtained from human TA and the effect of adenosine receptor ligands on myofibroblast transformation were investigated. RESULTS: The experiments showed that the protein and messenger RNA levels of α-smooth muscle actin in non-PD TA cells and PD plaque-derived cells were significantly higher in cells exposed to TGF-ß1 than those not treated with TGF-ß1. 2 of 4 adenosine receptors (ADORA1 and ADORA2B) were found to be expressed in both cell populations. Among various adenosine receptor agonists/antagonist investigated, only ADORA2B agonist, BAY 60-6583, significantly inhibited myofibroblast transformation in a concentration-dependent manner when applied simultaneously with TGF-ß1 (IC50 = 30 µmol/L). CLINICAL TRANSLATION: ADORA2B agonists may be clinically efficacious in early-stage PD. STRENGTHS & LIMITATIONS: The strength of this study is the use of primary fibroblasts from human TA. Limitation of the study is the high concentrations of the ligands used. CONCLUSION: The effect of an ADORA2B agonist on TGF-ß1-induced myofibroblast transformation shows a novel potential therapeutic target for PD if applied during early, non-stable phase of PD. Mateus M, Ilg MM, Stebbeds WJ, et al. Understanding the Role of Adenosine Receptors in the Myofibroblast Transformation in Peyronie's Disease. J Sex Med 2018;15:947-957.

TGF-ß1 induces formation of TSG-6-enriched extracellular vesicles in fibroblasts which can prevent myofibroblast transformation by modulating Erk1/2 phosphorylation.

Extracellular vesicles have emerged as important mediators of cell-to-cell communication in the pathophysiology of fibrotic diseases. One such disease is Peyronie's disease (PD), a fibrotic disorder of the penis caused by uncontrolled transformation of resident fibroblasts to alpha-smooth muscle actin positive myofibroblasts. These cells produce large amounts of extracellular matrix, leading to formation of a plaque in the penile tunica albuginea (TA), causing pain, penile curvature, and erectile dysfunction. We have used primary fibroblasts derived from the TA of PD patients to explore the role of transforming growth factor beta 1 (TGF-ß1), a key signalling factor in this process. TGF-ß1 treatment elicited a range of responses from the myofibroblasts: (i) they secreted extracellular vesicles (EVs) that were more numerous and differed in size and shape from those secreted by fibroblasts, (ii) these EVs prevented TGF-ß1-induced transformation of fibroblasts in a manner that was dependent on vesicle uptake and (iii) they prevented phosphorylation of Erk1/2, a critical component in modulating fibrogenic phenotypic responses, but did not affect TGF-ß1-induced Smad-signalling. We posit that this effect could be linked to enrichment of TSG-6 in myofibroblast-derived EVs. The ability of myofibroblast-derived vesicles to prevent further myofibroblast transformation may establish them as part of an anti-fibrotic negative feedback loop, with potential to be exploited for future therapeutic approaches.

Hydroxypyridone anti-fungals selectively induce myofibroblast apoptosis in an in vitro model of hypertrophic scars.

Hypertrophic scars are a common complication of burn injuries, yet there are no medications to prevent their formation. During scar formation, resident fibroblasts are transformed to myofibroblasts which become resistant to apoptosis. Previously, we have shown that hydroxypyridone anti-fungals can inhibit transformation of fibroblasts, isolated from hypertrophic scars, to myofibroblasts. This study aimed to investigate if these drugs can also target myofibroblast persistence. Primary human dermal fibroblasts, derived from burn scar tissue, were exposed to transforming growth factor beta-1 (TGF-ß1) for 72 h to induce myofibroblast transformation. The cells were then incubated with three hydroxypyridone anti-fungals (ciclopirox, ciclopirox ethanolamine and piroctone olamine; 0.03-300 µM) for a further 72 h. The In-Cell ELISA method was utilised to quantify myofibroblast transformation by measuring alpha-smooth muscle actin (α-SMA) expression and DRAQ5 staining, to measure cell viability. TUNEL staining was utilised to assess if the drugs could induce apoptosis. When given to established myofibroblasts, the three hydroxypyridones did not reverse myofibroblast transformation, but instead elicited a concentration-dependent decrease in cell viability. TUNEL staining confirmed that the hydroxypyridone anti-fungals induced apoptosis in established myofibroblasts. This is the first study to show that hydroxypyridone anti-fungals are capable of inducing apoptosis in established myofibroblasts. Together with our previous results, we suggest that hydroxypyridone anti-fungals can prevent scar formation by preventing the formation of new myofibroblasts and by reducing the number of existing myofibroblasts.

European Society of Sexual Medicine consensus statement on the use of animal models for studying Peyronie's disease.

Introduction: Animal models are frequently used for translational research in Peyronie's disease (PD). However, due to lack of availability of guidelines, there is some heterogeneity in study design, data reporting, and outcome measures. Aim: This European Society for Sexual Medicine consensus statement aims to provide guidance in utilization of animal models in PD research in a standardized and uniform fashion. Methods: PubMed was searched for studies using animal models for PD. The following search terms were used: ("Peyronie's disease" OR "penile fibrosis" OR "penile curvature" OR "induration penis plastica" OR "erectile dysfunction") AND ("rodent" OR "mouse" OR "mice" OR "rat" OR "rabbit"). Outcomes: This European Society for Sexual Medicine statement describes best practice guidelines for utilization of animals in PD research: power calculation, details of available models, surgical procedures, and measurement techniques, while highlighting possible pitfalls and translational limitations of the models. Results: In total, 2490 studies were retrieved and 2446 articles were excluded. A total of 44 studies were included, of which 40 studies used rats, 1 study used both rats and mice, 1 study used a genetic mouse model, and 2 studies used rabbits. A significant number of the studies (70.5%) used transforming growth factor ß 1 for induction of fibrosis. Oxford 2011 Levels of Evidence criteria could not be applied due to the nature of the studies. Conclusion: Despite certain limitations of PD animal models presented, we aimed to provide guidance for their appropriate use in translational research, with the purpose of improving study quality and reproducibility as well as facilitating interpretation of reported results and conclusions.

Phenotypic screening of 1,953 FDA-approved drugs reveals 26 hits with potential for repurposing for Peyronie's disease.

Drug repurposing has been shown to bring safe medications to new patient populations, as recently evidenced by the COVID-19 pandemic. We investigated whether we could use phenotypic screening to repurpose drugs for the treatment of Peyronie's disease (PD). PD is a fibrotic disease characterised by continued myofibroblast presence and activity leading to formation of a plaque in the penile tunica albuginea (TA) that can cause pain during erection, erectile dysfunction, and penile deformity. PD affects 3-9% of men with treatment options limited to surgery or injection of collagenase which can only be utilised at late stages after the plaque is formed. Currently there are no approved medications that can be offered to patients presenting with early disease before the formation of the plaque. Drug repurposing may therefore be the ideal strategy to identify medical treatments to address this unmet medical need in early PD. We used primary human fibroblasts from PD patients in a phenotypic screening assay that measures TGF-ß1-induced myofibroblast transformation which is the main cellular phenotype that drives the pathology in early PD. A library of FDA-approved 1,953 drugs was screened in duplicate wells at a single concentration (10 µM) in presence of TGF-ß1. The myofibroblast marker α-SMA was quantified after 72h incubation. A positive control of SB-505124 (TGF-ß1 receptor antagonist) was included on each plate. Hits were defined as showing >80% inhibition, whilst retaining >80% cell viability. 26 hits (1.3%) were identified which were divided into the following main groups: anti-cancer drugs, anti-inflammation, neurology, endocrinology, and imaging agents. Five of the top-ten drugs that increase myofibroblast-transformation appear to act on VEGFR. This is the first phenotypic screening of FDA-approved drugs for PD and our results suggest that it is a viable method to predict drugs with potential for repurposing to treat early PD.

Phenotypic screening identifies hydroxypyridone anti-fungals as novel medicines for the prevention of hypertrophic scars.

Although hypertrophic scarring affects ∼91% of burn patients annually, there is no drug to prevent this common complication. Hypertrophic scars are a result of dysregulated wound healing, characterised by persistent myofibroblast transformation and the excessive accumulation of extracellular matrix (ECM). Due to the multi-mechanistic nature of the scarring process, target-based approaches for identifying novel drugs have failed. Primary human dermal fibroblasts, derived from burn scar tissue, were exposed to transforming growth factor-beta 1 (TGF-ß1) to induce myofibroblast transformation. A phenotypic screening assay, measuring alpha-smooth muscle actin (α-SMA) expression, was developed to screen 1,954 approved drugs. Drugs that elicited >80% inhibition of α-SMA expression, and >80% cell viability were progressed as candidate drugs. Anti-myofibroblast activity of the candidates was confirmed before investigating their effects on extracellular matrix (ECM) production and keratinocyte epithelial-mesenchymal transition (EMT). TGF-ß1 induced myofibroblast transformation in primary human dermal fibroblasts (Emax = >3 ng/mL). The assay was optimised and validated (Z' = 0.59), before screening 1,954 approved drugs. 90 drugs were identified as hits and hydroxypyridone anti-fungals selected for further testing. Concentration-response curves for these drugs confirmed their concentration-dependent anti-myofibroblast activity (IC50 = 1.4 - 16.7 µM). Hydroxypyridone anti-fungals were also found to successfully reduce ECM production and keratinocyte EMT. This is the first study to screen approved drugs in primary human dermal fibroblasts. Hydroxypyridone anti-fungals were found to prevent myofibroblast transformation, ECM production and keratinocyte EMT suggesting they could be repurposed to prevent hypertrophic scarring.

European Society for Sexual Medicine Consensus Statement on the Use of the Cavernous Nerve Injury Rodent Model to Study Postradical Prostatectomy Erectile Dysfunction.

INTRODUCTION: Rodent animal models are currently the most used in vivo model in translational studies looking into the pathophysiology of erectile dysfunction after nerve-sparing radical prostatectomy. AIM: This European Society for Sexual Medicine (ESSM) statement aims to guide scientists toward utilization of the rodent model in an appropriate, timely, and proficient fashion. METHODS: MEDLINE and EMBASE databases were searched for basic science studies, using a rodent animal model, looking into the consequence of pelvic nerve injury on erectile function. MAIN OUTCOME MEASURES: The authors present a consensus on how to best perform experiments with this rodent model, the details of the technique, and highlight possible pitfalls. RESULTS: Owing to the specific issue-basic science-Oxford 2011 Levels of Evidence criteria cannot be applied. However, ESSM statements on this topic will be provided in which we summarize the ESSM position on various aspects of the model such as the use of the Animal Research Reporting In Vivo Experiments guideline and the of common range parameter for nerve stimulation. We also highlighted the translational limits of the model. CONCLUSION: The following statements were formulated as a suggestive guidance for scientists using the cavernous nerve injury model. With this, we hope to standardize and further improve the quality of research in this field. It must be noted that this model has its limitations. Weyne E, Ilg MM, Cakir OO, et al. European Society for Sexual Medicine Consensus Statement on the Use of the Cavernous Nerve Injury Rodent Model to Study Postradical Prostatectomy Erectile Dysfunction. Sex Med 2020;8:327-337.

Pathophysiology and Future Therapeutic Perspectives for Resolving Fibrosis in Peyronie's Disease.

INTRODUCTION: Peyronie's disease (PD) is a debilitating affliction for the male population, causing severe curvatures to the erect penis and erectile dysfunction in about 50% of men. This deviation of the penis significantly impairs sexual intercourse and causes depression and strains in the relationship. As of today, medical treatment options are few and far between, with surgery remaining as the sole reliable treatment. AIM: To give a general overview regarding fibrosis and the specific role of extracellular matrix, macrophages, and myofibroblasts in PD. Additionally, we will provide an overview of past and present research and how this has shaped our vision concerning the pathophysiology of PD. METHODS: We performed a non-systematic literature review using the search terms "fibrosis," "pathophysiology," "myofibroblast," "extracellular matrix," "Peyronie's disease," and "drug discovery." MAIN OUTCOME MEASURE: We assessed current knowledge regarding fibrosis in PD and the possibility to use this knowledge for new treatment options. RESULTS: Interpreting findings from the most recent next-generation sequencing, in vitro and in vivo PD research, we provide novel insights for the pathophysiology of PD. Using this knowledge, we will attempt to provide future directions for PD research and drug discovery, which is urgently needed, because its treatment has essentially been stagnating for about 30 years. CONCLUSION: Historically, PD has not been studied as widely as kidney, lung, or hepatic fibrosis, and our knowledge of its pathophysiology still remains relatively obscure. Nonetheless, recent breakthroughs using stem cells, next-generation sequencing, and phenotypical screening assays bring us several steps closer to filling the gaps in our knowledge. In the near future, clinical trials will prove essential to translate this plethora of preclinical data into usable tools that can improve the lives of many of our patients. Milenkovic U, Ilg MM, Cellek S, et al. Pathophysiology and Future Therapeutic Perspectives for Resolving Fibrosis in Peyronie's Disease. Sex Med Rev 2019;7:679-689.

Antifibrotic Synergy Between Phosphodiesterase Type 5 Inhibitors and Selective Oestrogen Receptor Modulators in Peyronie's Disease Models.

BACKGROUND: Peyronie's disease (PD) is a fibrotic disorder of the penile tunica albuginea, characterised by the formation of a localised fibrous plaque that can lead to deformity and erectile dysfunction. Nonsurgical therapeutic options for PD are limited in efficacy and safety. Myofibroblasts are key cells in the pathogenesis of PD, and inhibition of myofibroblast transformation has been suggested as a therapeutic option. OBJECTIVE: To identify potential drugs using a novel phenotypic assay and then to test them using in vitro and in vivo models of PD. DESIGN, SETTING, AND PARTICIPANTS: We have developed and validated a phenotypic screening assay that measures myofibroblast transformation, by which we tested 21 compounds that were suggested to be efficacious in treating PD. The successful hits from this assay were further tested using in vitro and in vivo models of PD. RESULTS AND LIMITATIONS: The new assay was able to detect transforming growth factor-ß1-induced myofibroblast transformation. Using this assay, phosphodiesterase type 5 inhibitors (PDE5i) and selective oestrogen receptor modulators (SERMs) were identified to significantly inhibit myofibroblast transformation. A PDE5i (vardenafil) and an SERM (tamoxifen) inhibited myofibroblast transformation, collagen gel contraction, and extracellular matrix production in a synergistic fashion. In a rat model of PD, the antifibrotic effect of the combination of vardenafil and tamoxifen was greater than that of each drug alone. This study is limited by not providing a molecular mechanism for the proposed synergy. CONCLUSIONS: This is the first demonstration of a synergistic activity between a PDE5i and an SERM discovered through a phenotypic screening approach. Future clinical trials using a combination of these drugs should be considered during the active phase of PD, given the early evidence of benefit in both in vitro and in vivo models. PATIENT SUMMARY: This report suggests that the combination of a phosphodiesterase type 5 inhibitor and a selective oestrogen receptor modulator may be efficacious in treating Peyronie's disease in its active phase.

The Complete Genome Sequence of Clostridium aceticum: a Missing Link between Rnf- and Cytochrome-Containing Autotrophic Acetogens.

UNLABELLED: Clostridium aceticum was the first isolated autotrophic acetogen, converting CO2 plus H2 or syngas to acetate. Its genome has now been completely sequenced and consists of a 4.2-Mbp chromosome and a small circular plasmid of 5.7 kbp. Sequence analysis revealed major differences from other autotrophic acetogens. C. aceticum contains an Rnf complex for energy conservation (via pumping protons or sodium ions). Such systems have also been found in C. ljungdahlii and Acetobacterium woodii. However, C. aceticum also contains a cytochrome, as does Moorella thermoacetica, which has been proposed to be involved in the generation of a proton gradient. Thus, C. aceticum seems to represent a link between Rnf- and cytochrome-containing autotrophic acetogens. In C. aceticum, however, the cytochrome is probably not involved in an electron transport chain that leads to proton translocation, as no genes for quinone biosynthesis are present in the genome. IMPORTANCE: Autotrophic acetogenic bacteria are receiving more and more industrial focus, as CO2 plus H2 as well as syngas are interesting new substrates for biotechnological processes. They are both cheap and abundant, and their use, if it results in sustainable products, also leads to reduction of greenhouse gases. Clostridium aceticum can use both gas mixtures, is phylogenetically not closely related to the commonly used species, and may thus become an even more attractive workhorse. In addition, its energy metabolism, which is characterized here, and the ability to synthesize cytochromes might offer new targets for improving the ATP yield by metabolic engineering and thus allow use of C. aceticum for production of compounds by pathways that currently present challenges for energy-limited acetogens.

A Dynamic Role of TBX3 in the Pluripotency Circuitry.

Pluripotency represents a cell state comprising a fine-tuned pattern of transcription factor activity required for embryonic stem cell (ESC) self-renewal. TBX3 is the earliest expressed member of the T-box transcription factor family and is involved in maintenance and induction of pluripotency. Hence, TBX3 is believed to be a key member of the pluripotency circuitry, with loss of TBX3 coinciding with loss of pluripotency. We report a dynamic expression of TBX3 in vitro and in vivo using genetic reporter tools tracking TBX3 expression in mouse ESCs (mESCs). Low TBX3 levels are associated with reduced pluripotency, resembling the more mature epiblast. Notably, TBX3-low cells maintain the intrinsic capability to switch to a TBX3-high state and vice versa. Additionally, we show TBX3 to be dispensable for induction and maintenance of naive pluripotency as well as for germ cell development. These data highlight novel facets of TBX3 action in mESCs.