Human Bladder Fibroblasts

Human Bladder Fibroblasts (HBFs) are primary mesenchymal cells derived from the lamina propria, the underlying layer of connective tissue in the human bladder. The lamina propria supports the overlying urothelium, maintains ECM homeostasis, and facilitates tissue repair after injury. HBFs in culture have an elongated spindle shape with extended actin-rich processes. They can form whirl-like growth patterns as cell colonies expand. As typical fibroblasts, HBFs express classical fibroblast markers such as vimentin and fibronectin. HBFs can upregulate α-SMA expression in an activated state and thus can model some aspects of the myofibroblast phenotype.

Biologically, they are responsible for ECM synthesis and remodeling by producing collagen, elastin, matrix proteases, and signaling factors that modulate tissue stiffness and microenvironmental organization. Bladder fibroblasts are sensitive to inflammatory cytokines and pathogenic stimulation, and are thus important models for IC/BPS and chronic cystitis pathobiology and bladder fibrosis. They are also critical for modeling epithelial-mesenchymal communication, wound repair, and barrier dysfunction, given their close associations with urothelial cells and smooth muscle cells in vivo.

In bladder cancer studies, HBFs represent a physiologically relevant cell system to model the conversion to cancer-associated fibroblasts (CAFs), and they can be used to study tumor invasion, matrix remodeling, and paracrine signaling in the bladder tumor microenvironment. HBFs are broadly used to study bladder inflammation, fibrosis, urothelial regeneration, drug screening and toxicology, and engineered bladder tissues, and are being incorporated into 3D culture and organ-on-chip technologies.