Presentations

Abstract

Introduction: Lower Urinary Tract Symptoms (LUTS) are a common collection of symptoms that affect the urinary system, often associated with Benign Prostatic Hyperplasia (BPH), which is non-malignant enlargement of the prostate gland. BPH primarily affects older men 50 or above and approximately 80% of all men in their 80s will acquire this disease leading to significant discomfort and disruption in daily life. The enlargement of the prostate compresses the urethra, causing difficulties in both storing and voiding urine, which manifests as LUTS. These symptoms can include frequent urination, urgency, weak urine flow, urinary tract infections as well as others. For those diagnosed, BPH and LUTS can significantly impact the quality of life, reduce the ability to perform daily activities as well as increase anxiety or stress about symptom management. Furthermore, the complex nature of BPH underscores the need for better disease characterization as well as advancements in understanding the pathophysiology of BPH. Investigation into this disease pathology, combined with morphological causation analysis could lead to more effective management of BPH, thus reducing the burden of the disease and enhancing the quality of life for those affected. Our team has demonstrated that inducing BPH in mice via a steroid hormone imbalance model increases prostatic macrophages and triggers their migration into the luminal space, where they differentiate into lipid-rich foam cells. Preliminary studies link these foam cells and epithelial lipid accumulation to LUTS/BPH, however, their impact on urinary function remains unclear. We identified the chemoattractant CXCL17 as a potential driver of macrophage migration. Additionally, foam cells express growth factors and chemokines that could promote fibrosis, proliferation, angiogenesis, and inflammation. We hypothesize that epithelial cytokines facilitate the translocation of macrophages into the lumen and the formation of foam cells, driving the development of BPH and LUTS, along with related urinary dysfunction. This hypothesis will be evaluated through identifying factors derived from epithelial cells in foam cell-rich regions in human prostates and characterizing the effect of Cxcl17 deficiency in mice.

Methods: Preliminary experiments performed single-cell RNA-sequencing (scRNA-seq) to identify epithelial chemokines and foam cell transcriptome in response to steroid hormone imbalance. We also assessed lipid accumulation using Oil Red O staining and in situ hybridization assessing Cxcl17 upregulation in T+E2 versus Sham controls. Currently, we are testing a Cxcl17-knockout (KO) mouse model (B6;129S5-Cxcl17tm1Lex/Mmucd) and wild-type (WT) littermates exposed to steroid hormone imbalance via subcutaneous implantation of testosterone and estradiol. Prostate tissues will be collected at two or twelve weeks for histological analysis. This includes immunohistochemistry to identify macrophages (CD68), neutrophils (Ly6G), B-cells (CD20), T-cells (CD3), and mast cells (toluidine blue), as well as collagen content using picrosirius red staining and cell proliferation via Ki-67. Urinary function will be evaluated using the Mouse Urovoid system and cystometry. In human BPH, chemokines driving foam cell migration will be identified using laser capture microdissection (LCM), RNA isolation, and NanoString "Chemokine Signaling" panel. Proteomic analysis with Liquid Chromatography-Electrospray Ionization-tandem Mass Spectrometry (LC/ESI-MS/MS) and Parallel Reaction Monitoring (PRM-MS) will validate chemokine profiles and elucidate molecular pathways involved in BPH.

Results: Our preliminary data utilizing the T+E2 model showed an early increase in macrophages and their translocation into the prostate lumen, where they differentiated into foam cells, followed by fibrosis at three months. These foam cells accumulated lipids and expressed high levels of the pro-inflammatory protein osteopontin. scRNA-seq revealed a foam cell cluster in T+E2 mice, resembling foamy macrophages in atherosclerotic plaques. We also identified upregulation of Cxcl17 in epithelial cells which was confirmed by in situ hybridization. Uroflow conducted on WT and Cxcl17-KO mice showed no difference in basal urinary function before pellet implantation and we are currently tracking the developing changes post-surgery.

Conclusion: In conclusion, our preliminary data suggest that CXCL17 is the primary driver of macrophage luminal translocation in the prostate, a process necessary for foam cell formation, which likely contributes to the pathogenesis of BPH and associated urinary dysfunction. Successful completion of this study will confirm the CXCL17-dependence of this process, with potential alternative cytokines in human disease. The findings will identify molecular targets for potential therapeutic interventions, advancing our understanding of BPH pathophysiology as well as LUTS.