Lactobacillus-Polydopamine System for Targeted Drug Delivery in Overactive Bladder: Evidence from Bladder Cell Spheroids, Rat Models, and Urinary Microbiome Profiling.

Introduction: Overactive bladder (OAB) is a highly prevalent condition with limited treatment options due to poor efficacy, side effects, and patient compliance. Novel drug delivery systems that can target the bladder wall may improve OAB therapy. Methods: We explored a polydopamine (PDA)-coated lactobacillus platform as a potential carrier for localized OAB treatment. Urinary microbiome profiling was performed to identify the presence of lactobacillus in healthy and OAB groups. Lactobacillus-PDA nanoparticles were synthesized and characterized by electron microscopy and spectrophotometry. A rat bladder perfusion model and human bladder smooth muscle cell spheroids were used to assess the distribution and penetration of the nanoparticles. The efficacy of the Lactobacillus-PDA system (LPS) for delivering the antimuscarinic drug solifenacin was evaluated in an OAB rat model. Results: Urinary microbiome profiling revealed lactobacillus as a dominant genus in both healthy and OAB groups. The synthesized Lactobacillus-PDA nanoparticles exhibited uniform size and optical properties. In the rat bladder perfusion model, the nanoparticles distributed throughout the bladder wall and smooth muscle without toxicity. The nanoparticles also penetrated human bladder smooth muscle cell spheroids. In the OAB rat model, LPS facilitated the delivery of solifenacin and improved treatment efficacy. Discussion: The results highlight LPS as a promising drug carrier for targeted OAB therapy via penetration into bladder tissues. This bacteriotherapy approach may overcome limitations of current systemic OAB medications. Lactobacillus, a probiotic bacterium present in the urinary tract microbiome, was hypothesized to adhere to and penetrate the bladder wall when coated with PDA nanoparticles, making it a suitable candidate for localized drug delivery.

Polo-like kinase 1 inhibition modulates urinary tract smooth muscle contraction and bladder cell transcriptional programs.

The serine/threonine kinase polo-like kinase 1 (PLK1) is a master regulator of cell proliferation and contraction, but its physiological role in the lower urinary tract is unknown. We utilized transcriptomic programs of human bladder smooth muscle cells (hBSMCs), 3D bladder spheroid viability assays, and human ureterovesical junction contractility measurements to elucidate the impacts of PLK1 inhibition. This work reveals PLK1 reduction with the selective inhibitor TAK-960 (500 nM) suppresses high K+-evoked contractions of human urinary smooth muscle ex vivo while decreasing urothelial cell viability. Transcriptomic analysis of hBSMCs treated with TAK-960 shows modulation of cell cycle and contraction pathways, specifically through altered expression of Cys2/His2-type zinc finger transcription factors. In bladder spheroids, PLK1 inhibition also suppresses smooth muscle contraction protein filamin. Taken together, these findings establish PLK1 is a critical governor of urinary smooth muscle contraction and urothelial proliferation with implications for lower urinary tract disorders. Targeting PLK1 pharmacologically may therefore offer therapeutic potential to ameliorate hypercontractility and aberrant growth. Further elucidation of PLK1 signaling networks promises new insights into pathogenesis and much needed treatment advances for debilitating urinary symptoms.