Evaluation of the influence of angiotensin type 1 receptor expression under disease conditions in an autoimmune cystitis animal model - PROJECT SUMMARY IC/BPS is challenging to diagnose as the symptoms overlap with other bladder diseases, making the condition often misdiagnosed. Symptoms include lack of infection, frequent urination, increased residual urine volume, painful intercourse, chronic pelvic pain, and an increased urge to urinate. Fundamental knowledge gaps exist in our understanding of what causes IC/BPS; however, a recent theory suggests (angiotensin II) Ang-II signaling may play a role in bladder disease pathology as there are similarities between IC/BPS and other organ tissues where Ang-II signaling is well established. For example, in the lungs, heart, liver, and kidney, one of the Ang-II receptors, angiotensin receptor 1a (AT1R), is upregulated with tissue inflammation and fibrosis. However, the functional role AT1R plays in bladder pathophysiology is unknown. Preliminary data using our AT1aR-tdTomato mouse line show that AT1R mRNA and protein are expressed in both the urothelium and the detrusor smooth muscle from naïve animals. Furthermore, the AT1aR-tdTomato area of fluorescence increases in our acute cystitis mouse model, suggesting an increase in AT1R-expressing cells following inflammatory tissue insult. Based on preliminary data, I propose to investigate if Ang-II signaling contributes to pathological changes in the bladder in a chronic bladder inflammatory mouse model. It is challenging to represent IC/BPS with one single animal model; therefore, it is worth further investigating the chronic experimental autoimmune cystitis (EAC) where I will specifically examine AT1R expression. In aim 1, I hypothesize that bladder AT1R expression increases in an EAC mouse model that can be attenuated with inhibition of mast cell activity. I will utilize our AT1aR-tdTomato mouse line for the EAC model. Then, I will utilize RNA-sequencing, RNAscope in situ hybridization, western blot, and immunohistochemistry to evaluate AT1R expression in naïve, vehicle, and EAC bladder tissue. In aim 2, I hypothesize that AT1R knocked out of the urothelial cells will reduce bladder inflammation, mast cell infiltration, pelvic hypersensitivity, and micturition frequency in an EAC mouse model. I will utilize a UPK2cre-AT1aR knock-out mouse line to determine the influence of urothelial AT1R on EAC symptoms. I will use behavioral assays to assess pelvic sensitivity and urinary function. Additionally, I will use biochemical and histological analyses to quantify inflammatory cytokines and AT1R expression. Collectively, the goal of this proposal is to determine the role of local Ang-II signaling in chronic bladder disease pathophysiology to aid in the development of more effective treatments.
