huCLDN9-HEK293 is primarily used in biomedical research as a cellular model expressing human claudin-9 (CLDN9), a tight junction protein involved in cell adhesion and barrier function. This cell line, derived from HEK293 cells and engineered to express human CLDN9, serves as a valuable tool for studying the role of claudin proteins in epithelial and endothelial barriers, particularly in the inner ear and other tissues where CLDN9 is naturally expressed. It is commonly applied in studies related to hearing and auditory function, as CLDN9 mutations are linked to hereditary deafness. Researchers use this cell line to investigate protein-protein interactions, membrane permeability, and the functional impact of CLDN9 variants. Additionally, it supports drug development efforts targeting tight junction integrity and paracellular transport, especially in conditions involving barrier dysfunction. The model also aids in validating antibodies and diagnostic tools specific to CLDN9.