COL1A1 and interstitial lung disease: IF staining revealed that supernatants from RA-ILD patient serum-treated HL-60 cells transfected with Nr4a3 siRNA significantly increased the abundance of FN and COL1A1 in MRC-5 cells compared with supernatants from HL-60 cells treated with RA-ILD serum alone (Fig. 5b).