Human Bladder Epithelial Cells

Epithelial cells from the bladder (urothelial cells) line the inner surface of the urinary bladder, forming a specialized and highly impermeable barrier that prevents urine‑borne toxins and pathogens from reaching the underlying tissue. In vivo, the urothelium consists of basal, intermediate and umbrella cells; the latter express uroplakin (UPK1A/B, UPK2, UPK3A/B) and tight‑junction proteins (ZO‑1, claudin‑4) which confer its tensile strength and impermeability. In vitro, researchers can select from a range of urothelial cell models, from primary normal cells isolated from healthy bladder tissue to immortalized and cancer‑derived lines. Primary urothelial cells are typically cultured in urothelial‑specific medium with 10% fetal bovine serum, and retain the native 3‑layer architecture and UPK expression profile, making them ideal for in vitro studies of urothelial barrier‑function and toxicology. Immortalized normal urothelial cells like SV‑HUC‑1 (SV40‑transformed) provide a more stable non‑tumorigenic platform for long‑term experiments. Common bladder‑cancer lines include RT4 (low‑grade papillary carcinoma, doubling time 66-80 h), T24 (high‑grade carcinoma with H‑ras mutation, doubling time ≈19 h), 5637 (moderately differentiated, cytokine‑secreting) and UM‑UC‑3 (high‑grade, hyper‑triploid). These models have been used to investigate a variety of research topics: urothelial infection (UPEC invasion and intracellular bacterial communities), drug‑screening and antimicrobial‑peptide efficacy, bladder‑cancer signaling pathways (Ras‑MAPK, PI3K/AKT), environmental toxicology (BPA, heavy metals), and tissue‑engineering approaches for bladder reconstruction. Investigators can therefore select the appropriate cell line and culture system to faithfully recapitulate aspects of urothelial physiology and pathology in vitro.