Objective: To investigate the tendency and correlation between connective tissue growth factor (CTGF) and low density lipoprotein receptor-related protein (LRP) in human pulmonary fibroblasts-1 (HPF-1) induced by transforming growth factor beta1 (TGF-beta1) at different times.
Methods: After the HPF-1 cells were stimulated with TGF-beta1 (5 microg/L) at different times (0 h, 3 h, 6 h,12 h and 24 h),CTGF and LRP mRNA expressions were analyzed by RT-PCR. The same preparation steps of cell culture were repeated, then, the protein expressions were determined by Western Blot, co-immunoprecipitation Western Blot and immunocytochemistry.
Results: The expressions of CTGF and LRP mRNA had similar tendency, and LRP (224.87 +/- 7.00) correlated with CTGF (131.53 +/- 2.86) positively (r = 0.8402, P < 0.05). Furthermore, the protein expression levels had significant difference between 0 h (190.85 +/- 2.86) and 3 h (222.45 +/- 3.66) groups (F = 18.06, P < 0.01),and by immunoprecipitation, it was discovered that the quantity of CTGF bounded to LRP changes, which was similar to the result of LRP western blot. The analysis of immunocytochemistry disclosed the like results as well (3 h: 88.66 +/- 15.72, 0 h: 27.56 +/- 6.72, F = 244.36, P < 0.01).
Conclusion: The expression of LRP coincides with that of CTGF at the same stimulated time point of TGF-beta1. It suggests that LRP may be involved in the biological process of CTGF. And further research about LRP may provide a new direction to pulmonary fibrosis therapy.