B cell-induced collagen secretion and profibrotic markers expression are contact dependent, and the role of BAFF is dependent on soluble factors. (A) Levels of COL1A1, COL1A2, and COL3A1 mRNA were determined with RT-qPCR in SScHDF after incubation with medium (white bars), anti-μ-chain antibodies at 5 μg/ml (grey bars), or anti-μ and rhBAFF at 100 ng/ml (black bars) in the presence or absence of blood B cells. B cells were either in contact with SScHDF (contact) or seeded in the upper chamber of a transwell culture insert (transwell). Results were expressed as the fold change compared with samples from SScHDF alone with medium. (B) Collagen release by SScHDF was determined by the Sircol collagen dye-binding assay in 3 and 5 days of culture supernatants. (C) Levels of α-SMA, MMP9, and TIMP1 mRNA were determined with RT-qPCR in the same conditions as in panel A. Data are expressed as the median of duplicate samples of six independent experiments ± interquartile range. *P < 0.05; **P < 0.01.
François et al. Arthritis Research & Therapy 2013 15:R168 doi:10.1186/ar4352