Anti-Fibrogenic Therapy to Target Aging-Associated Urethra Dysfunction

About This Grant

Abstract The decline of urethral function with advancing age plays a crucial role in urinary incontinence in women. However, none of the current treatments address this decline, and the mechanisms by which aging impacts urethral physiology remain little known and largely unexplored. Our recently published work evaluated the effect of aging through functional, morphometric, and transcriptomics studies on the female mouse urethra. Similar to aged female humans, we demonstrated that aged mice have substantially lower functional leak point pressure and significant morphometric decline in striated muscle and elastin, with increased fibrotic connective tissues compared to young mice. Gene expression profiling of the whole urethra showed that myogenesis and fibrogenesis pathways were predominantly enriched in aged urethral tissue. Further investigation of the RNA- sequencing data revealed that aged urethral tissues had more fibrotic and extracellular remodeling gene expressions, such as connective tissue growth factor (Ctgf), compared to younger tissues. Connective tissue associated with striated muscle is primarily generated by resident Pdgfrα+ cells known as fibro-adipogenic progenitors (FAPs) with multilineage progenitor properties and a fibroblast-like phenotype. Immunofluorescence staining of Pdgfrα+ cells in the urethral striated muscle layer of both young and aged mice, coupled with RNAscope analysis in our preliminary studies, revealed an increased density of Pdgfrα+/Ly6a+ FAP cells and elevated Ctgf expression from these Pdgfrα+/Ly6a+ FAP cells in the striated muscle layer of the aged compared to young mouse urethra. These results suggest a critical role of Ctgf in FAP cells for urethral dysfunction. Therefore, we hypothesize that aged urethral tissue striated muscle dysfunction is attributed to increased fibrosis due to altered FAP cells that secrete factors such as Ctgf and that targeting Ctgf can improve urethral function. To test this hypothesis, Specific Aim 1 will focus on single-cell RNA sequencing of urethral tissues from three different age groups (young adult, middle-aged, and aged) to evaluate gene expression changes in FAP cells due to aging (Aim 1.1). Spatial transcriptomics will be used to define the FAP cell locations and their communication networks with surrounding tissues to better understand their role in female urethral dysfunction (Aim 1.2). Blocking CTGF activities has shown promise in treating fibrosis in other tissues and organs, and our current data shows that Ctgf is highly expressed in aged tissues. Therefore, in Specific Aim 2, we aim to evaluate the efficacy of a CTGF-antibody drug as a potential therapy for urethral dysfunction (Aim 2.1). By inhibiting the activities of CTGF, we aim to decrease the formation of fibrotic tissues in the urethra and preserve urethral function. The impact of our proposed work will result in a deeper understanding of female urethral dysfunction and provide new therapeutics for treating urethral dysfunction, offering new opportunities for advancements in this area.