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.

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.

Investigating the risk factors of penile arterial insufficiency and veno-occlusive dysfunction in patients with erectile dysfunction.

Objective: To investigate the risk factors for penile arterial insufficiency (PAI), which is a known cause of erectile dysfunction (ED). Methods: Patients who attended our urology clinic complaining of ED for more than 6 months were prospectively enrolled in this study over 1-year period. Patient consent was taken and ethical committee approval. Complete medical history and thorough general and local examination including body mass index (BMI), Peyronie's disease (PD) and penile size measurements (length and girth) were done for all of them. Laboratory tests included testosterone, lipid profile and glycated haemoglobin (HA1c). A penile duplex ultrasound study (PDU) was done for all patients after intracavernosal injection (ICI) with alprostadil. Peak systolic velocity (PSV) and end-diastolic velocity (EDV) were measured after 15 min. Statistical analysis was done using SPSS. Results: A total of 440 patients were enrolled in this analysis. The mean age was 48(23-81), and the mean BMI was 30 (18-51). Older patients had lower PSV (r = -0.361, P = 0.000) and higher EDV (r = 0.174, P = 0.001), and both correlations were highly statistically significant. Diabetics had lower PSV (r = -0.318, P = 0.000) and higher EDV (r = 0.139, P = 0.008), which were also highly statistically significant. Smokers had lower PSV (r = -0.140, P = 0.008) and higher EDV (r = 0.178, P = 0.001), which were highly statistically significant. Men with larger penises measured skin to tip had lower EDV (r = -0.119, P = 0.024), which was less significant. Interestingly, there was neither a significant correlation between BMI and PSV (0.16, P = 0.745) nor a significant correlation between testosterone and PSV (0.029, P = 0.552). Also, there was no correlation between PSV and both dyslipidaemia and penile PD. Conclusions: Ageing, tobacco consumption, DM and hypertension seem to have a negative impact on penile haemodynamics, which was statistically significant. In our patients, there was no statistically significant effect on penile haemodynamics in patients with increased BMI, low testosterone or PD or according to the size of the penis.