Transcriptional characteristics of type III procollagen gene in systemic scleroderma-derived fibroblast clones and their regulation by Radix Salviae miltiorrhizae

Abstract

Objective To study transcriptional characteristics of type Ⅲ procollagen gene in systemic scleroderma (SS)-derived fibroblast clones and their regulation by Radix Salviae miltiorrhizae(RSM).Methods Eight fibroblast clones with different collagen-producing capacity were previously obtained from patients with SS and normal human controls.Recombinant plasmids containing different deletions of the human alpha 1 chain of type 3 procollagen (COL3A1) gene promoter were constructed,and transiently transfected into the fibroblast clones.Dual-luciferase reporter assay system was used to evaluate the activities of these recombinants in the fibroblast clones and to select a proximal transcriptional regulatory sequence.Then,the fibroblast clones were transfected with the plasmid containing the selected regulatory sequence (phCOLH30.1) followed by the treatment with RSM injection (1 g/L) and active monomers of RSM,including salvianolic acid B (5 mg/L),tanshinone Ⅱ A (5 mg/L),danshensu (20 mg/L) and protocatechuic aldehyde (5 mg/L),for 48 hours.The transfected fibroblast clones receiving no drug treatment served as the water-soluble control,and those treated with only dimethyl sulfoxide as the lipid-soluble control.Subsequently,the fibroblasts were lysed and subjected to the quantification of cellular proteins and determination of luciferase activity.The activity of recombinant promoters was compared by t test for the selection of proximal transcriptional regulatory sequence,and the activity of phCOLH30.1 by two-way analysis of variance in the RSM-interfering test (if there was interaction,one-way analysis of variance was conducted; and if there was no interaction,the main effect was tested after the removal of interaction item).Results Of the 6 recombinants,the recombinant containing COL3A1 proximal promoter from -96 bp to +16 bp (phCOLH30.1) showed the highest transcriptional activity in nearly all of the fibroblast clones,and the activity was positively correlated with the collagen-producing capacity of fibroblast clones.Compared with the water-soluble control,RSM injection significantly downregulated the activity of phCOLH30.1 in fibroblast clones with high and low collagen-producing capacity from patients with SS (2.261 ± 0.619 vs.3.879 ± 0.309,1.462 ± 0.291 vs.2.150 ± 0.262,both P ＜ 0.01) and normal human controls (1.681 ± 0.263 vs.3.039 ± 0.271,1.121 ± 0.361 vs.2.223 ± 0.247,both P ＜ 0.01),salvianolic acid B decreased the phCOLH30.1 activity in SS-derived high collagen-producing fibroblast clones (2.309 ± 0.524,P ＜ 0.01 ) and in the normal control fibroblast clones with high and low collagen-producing capacity (2.126 ± 0.320 and 1.976 ± 0.362,both P ＜ 0.05).Tanshinone Ⅱ A only downregulated the phCOLH30.1 activity in SS-derived high collagen-producing fibroblast clones compared with the lipid-soluble control (2.975 ± 0.666 vs 5.379 ± 0.238,P ＜ 0.01 ).Neither danshensu nor protocatechuic aldehyde showed inhibitory effects on phCOLH30.1 activity in SS-derived or normal control fibroblast clones.Conclusions The type Ⅲ procollagen gene is activated at the transcriptional level in high collagen-producing fibroblast clones from patients with SS,and the activation could be suppressed by RSM injection,salvianolic acid B and tanshinone Ⅱ A. Key words: Scleroderma, systemic; Fibroblasts; Clone cells; Collagen type Ⅲ; Salvia miltiorrhiza