Wilke M. Post

Urgency urinary incontinence (UUI) and Alzheimer’s disease (AD) are highly comorbid conditions in women, but the underlying molecular mechanisms are largely unknown. Therefore, we used network enrichment analyses and an elaborate literature search to integrate the most significant genes from four genome-wide association studies (GWASs) and other genetic, expression and functional evidence into a molecular landscape of female UUI. This molecular landscape centers around local, i.e., bladder-based, processing of the AD-associated amyloid precursor protein (APP). To further elucidate how APP processing is implicated in the comorbidity between UUI and AD, we conducted polygenic risk score (PRS)-based analyses, which showed that genetic risk factors associated with AD and a decreased amyloid beta 42/40 blood level ratio (also) contribute to UUI susceptibility. In conclusion, APP processing constitutes a putative molecular link between UUI and AD, adding further weight to their clinical comorbidity and having implications for the treatment (and prevention) of both traits.

Purpose: Stress urinary incontinence (SUI) represents a major health burden in women, but a thorough understanding of the underlying molecular mechanisms is lacking. Our aim was to further elucidate these mechanisms to ultimately find new treatments. Materials and Methods: This study integrated the most significant genes from 4 genome-wide association studies (GWASs) of SUI in women with other genetic, expression, and/or functional evidence from the literature into a molecular landscape. A network enrichment analysis of the top SUI GWAS genes was conducted, followed by an extensive literature search to identify interactions between the proteins encoded by the GWAS genes and proteins/molecules implicated in SUI through other evidence. Results: In total, 188 GWAS genes were used for network enrichment analysis that yielded 12 networks, of which 8 were overlapping, with beta-catenin as the central protein. Based on this finding and our literature search, we built a molecular landscape of female SUI that centers on beta-catenin signaling. Other important functional landscape themes are epithelial-mesenchymal transition, NANOG signaling, and female sex hormone signaling. Conclusions: The molecular landscape of female SUI that we built based on genetic data provides novel molecular insights that may be instrumental for better understanding the etiology of SUI and developing novel SUI treatments.

Pelvic organ prolapse (POP) represents a major health care burden in women, but its underlying pathophysiological mechanisms have not been elucidated. We first used a case-control design to perform an exome chip study in 526 women with POP and 960 control women to identify single nucleotide variants (SNVs) associated with the disease. We then integrated the functional interactions between the POP candidate proteins derived from the exome chip study and other POP candidate molecules into a molecular landscape. We found significant associations between POP and SNVs in 54 genes. The proteins encoded by 26 of these genes fit into the molecular landscape, together with 43 other POP candidate molecules. The POP landscape is located in and around epithelial cells and fibroblasts of the urogenital tract and harbors four interacting biological processes—epithelial-mesenchymal transition, immune response, modulation of the extracellular matrix, and fibroblast function—that are regulated by sex hormones and TGFB1. Our findings were corroborated by enrichment analyses of differential gene expression data from an independent POP cohort. Lastly, based on the landscape and using vaginal fibroblasts from women with POP, we predicted and showed that metformin alters gene expression in these fibroblasts in a beneficial direction. In conclusion, our integrated molecular landscape of POP provides insights into the biological processes underlying the disease and clues towards novel treatments.

Stress urinary incontinence (SUI) is a common and burdensome condition. Because of the large knowledge gap around the molecular processes involved in its pathophysiology, the aim of this review was to provide a systematic overview of genetic variants, gene and protein expression changes related to SUI in human and animal studies. On 5 January 2021, a systematic search was performed in Pubmed, Embase, Web of Science, and the Cochrane library. The screening process and quality assessment were performed in duplicate, using predefined inclusion criteria and different quality assessment tools for human and animal studies respectively. The extracted data were grouped in themes per outcome measure, according to their functions in cellular processes, and synthesized in a narrative review. Finally, 107 studies were included, of which 35 used animal models (rats and mice). Resulting from the most examined processes, the evidence suggests that SUI is associated with altered extracellular matrix metabolism, estrogen receptors, oxidative stress, apoptosis, inflammation, neurodegenerative processes, and muscle cell differentiation and contractility. Due to heterogeneity in the studies (e.g., in examined tissues), the precise contribution of the associated genes and proteins in relation to SUI pathophysiology remained unclear. Future research should focus on possible contributors to these alterations.

Aim: To perform a systematic review summarizing the knowledge of genetic variants, gene, and protein expression changes in humans and animals associated with urgency urinary incontinence (UUI) and to provide an overview of the known molecular mechanisms related to UUI.Methods: A systematic search was performed on March 2, 2020, in PubMed, Embase, Web of Science, and the Cochrane library. Retrieved studies were screened for eligibility. The risk of bias was assessed using the ROBINS‐I (human) and SYRCLE (animal) tool. Data were presented in a structured manner and in the case of greater than five studies on a homogeneous outcome, a meta‐analysis was performed.Results: Altogether, a total of 10,785 records were screened of which 37 studies met the inclusion criteria. Notably, 24/37 studies scored medium‐high to high on risk of bias, affecting the value of the included studies. The analysis of 70 unique genes and proteins and three genome‐wide association studies showed that specific signal transduction pathways and inflammation are associated with UUI. A meta‐analysis on the predictive value of urinary nerve growth factor (NGF) levels showed that increased urinary NGF levels correlate with UUI.Conclusion: The collective evidence showed the involvement of two molecular mechanisms (signal transduction and inflammation) and NGF in UUI, enhancing our understanding of the pathophysiology of UUI. Unfortunately, the risk of bias was medium‐high to high for most studies and the value of many observations remains unclear. Future studies should focus on elucidating how deficits in the two identified molecular mechanisms contribute to UUI and should avoid bias.

Background: Pelvic organ prolapse (POP) represents a major health care burden in women but its underlying pathophysiological mechanisms have not been elucidated. Objective: To integrate the results from a large scale exome chip study with published genetic and expression data into a molecular landscape of POP. Design, setting, and participants: The exome chip study was conducted in 526 women with POP and 960 healthy controls. To corroborate the findings, we analysed differential gene expression data from 12 POP patients. Vaginal fibroblasts from 4 women with POP were used to test the effect of the anti-diabetic drug metformin. Outcome measurements and statistical analysis: The exome chip study used a case-control design to identify single nucleotide variants (SNVs) associated with POP after Bonferroni correction. The molecular landscape was built using the UniProt and PubMed databases to identify functional interactions between the POP candidate genes/proteins. We performed enrichment and upstream regulator analyses of the differentially expressed genes. The effect of metformin in fibroblasts was assessed using one-sample t-test. Results and limitations: We found significant association between POP and SNVs in 54 genes. The proteins encoded by 26 of these genes fit into a molecular landscape, together with 37 other POP candidate molecules and two POP-implicated microRNAs. This landscape is located in and around epithelial cells and fibroblasts of the urogenital tract and harbors four interacting biological processes - epithelial-mesenchymal transition, immune response, modulation of the extracellular matrix, and fibroblast function - that are regulated by sex hormones and TGFB1. Based on the landscape, we predicted and showed that metformin alters gene expression in fibroblasts of POP patients in a beneficial direction. The main limitation of our study is that we have no independent replication of the exome chip results. Conclusions: The integrated molecular landscape of POP that we built provides insights into the biological processes underlying the disease and clues towards novel treatments. Patient summary: We reported the first exome chip study of POP and combined the genes identified in this study with other data from the literature to build a ‘molecular landscape’ of POP. This landscape will advance our understanding of the disease and may lead to novel treatments.