Connective tissue growth factor (CTGF) is a cysteine-rich protein that promotes extracellularmatrix deposition.CTGF is selectively induced by transforming growth factor β and des-Arg kallidin in lungfibroblasts and increases steady-state mRNA levels of α type I collagen,5α-integrin and fibronectin infibroblasts.Bronchial epithelial cells have been proposed to functionally interact with lung fibroblasts.Wetherefore investigated if bronchial epithelial cells are able to synthesize CTGF.Human bronchial epithelialcells were grown to subconfluence in standard growth media.Proliferating cells grown in small airwaygrowth media were harvested following starvation for up to 24 h.Expression of CTGF transcripts wasmeasured by PCR.Immunocytochemistry was also completed using a commercially available antibody.The cells expressed readily detectable CTGF transcripts.Starvation of these cells resulted in a quantitativedecline of CTGF transcripts.Direct sequencing of the PCR product identified human CTGF.Immunocy-tochemistry confirmed intracellular CTGF in the cells and none in negative control cells.We conclude thatbronchial epithelial cells could be a novel source of CTGF.Bronchial epithelial cell-derived CTGF could thusdirectly influence the deposition of collagen in certain fibrotic lung diseases. Connective tissue growth factor (CTGF) is a cysteine-rich protein that promotes extracellular matrix deposition. CTGF is selectively induced by transforming growth factor β and des-Arg kallidin in lung fibroblasts and enhance steady-state mRNA levels of α type I collagen, 5α-integrin and fibronectin infibroblasts. Bronchial epithelial cells have been to functionalally interact with lung fibroblasts. Examination of bronchial epithelial cells are able to synthesize CTGF. Human bronchial epithelial cells were grown to subconfluence in standard growth media. Proliferating cells grown in small air growth media were harvested following starvation for up to 24 h. Expression of CTGF transcripts wasmeasured by PCR. Immunocytochemistry was also completed using a commercially available antibody. The cells expressed readily detectable CTGF transcripts. Starvation of these cells resulted in a quantitative deline of CTGF transcripts. Direct sequencing of the PCR product identified human CTGF.Immunocytosis confirmed intracellular CTGF in the cells and none in negative control cells. We conclude thatbronchial epithelial cells could be a novel source of CTGF.Bronchial epithelial cell-derived CTGF could directly influence the deposition of collagen in certain fibrotic lung diseases.