6533b7d0fe1ef96bd125b30d

RESEARCH PRODUCT

CCL5(RANTES) inhibits TGFbeta1 induced collagen production in human bronchial epithelial cells by action of Smad protein

subject

description

Airway epithelial cells modulate bronchial remodelling in COPD and asthma. TGF-β1 up-regulation was observed in the bronchial epithelial cells of asthmatics and COPD patients. TGF-β is involved in airways remodelling mainly acting via the Smad pathway. Increased CCL5 was also observed in bronchi of patients with severe COPD. We investigated the effects of TGF-β1 on collagen type I, Smad 3-4 and 7 expression and the effects of CCL5 on TGF-β1-induced collagen production in human bronchial epithelial cells (16HBE).Cells were treated with 10ng/ml of TGF-β1, 10ng/ml of CCL5 and 10ng/ml of both TGF-β1 and CCL5 for 0,3 and 24 hours.TGF-b1 increased Smad3,Smad4 and collagen type I(p=0.0472, p=0.0433 and p<0.0001,respectively)mRNA at 24h. An increase of Smad7 mRNA was observed at 24h(p=0.0422).We observed a significant time-dependent increase in nuclear phospho-Smad3 at 3h(p=0.0079)and 24h (p=0.0079).Exposure to CCL5 showed an increase of collagen type I mRNA at both 3h and 24h(p=0.0017 and 0.0433,respectively)and an increase of Smad3 mRNA at 3h(p=0.0021. A decrease for Smad7 at both 3h and 24h(p=0.0111 and p=0.0009)was also observed. No changes were observed in nuclear p-Smad3 compared with controls.Combined treatments with CCL5 and TGF-β1 repressed TGF-β1-induced collagen type I,Smad3 and Smad4 mRNA transcription at 24h(p=0.0015, p=0.0367, p=0.0052, respectively, as well as TGF-β1-induced nuclear p-Smad3 protein levels both at 3h and 24h(p=0.0381).Our results indicate that TGF-β1 induction of collagen production is mediated mainly by phospho-Smad3. CCL5 inhibits TGF-β1-induced collagen production by modulating Smad activity