CEP33779 ameliorates pulmonary fibrosis associated with rheumatoid arthritis via the cross-talk between JAK2 and TGF-β 1 signaling pathway / 中华风湿病学杂志

ABSTRACT

Objective:Rat model of RA complicated with pulmonary fibrosis were constructed to observe the degree of improvement of pulmonary fibrosis in RA rats by JAK2 inhibitor CEP33779 and the possible mechanisms.Methods:①The RA models were constructed by subcutaneous injection of 0.2 ml (1 mg/ml) of bovine type Ⅱ collagen into the tail of the rats on the day of modeling development (d0); intratracheal injection of 100 μl bleomycin (2.5 mg/kg) was used to induce pulmonary fibrosis model at d13. In vivo study model rats were randomly divided into the normal group, pulmonary fibrosis group, pulmonary fibrosis CEP treatment group, RA complicated with pulmonary fibrosis group, and RA complicated pulmonary fibrosis CEP treatment group. Rats in the treatment group was given CEP (10 ml/kg) qd by gavage from d14 to week 4. The right hind foot of the rats was measured for joints swelling and the arthritis index score were measured, lung compliance (Cst) and lung specific gravity were measured. In addition, the pathological changes of the left lung were observed by HE and Masson staining, and the extracellular matrix level of the right lung was measured by protein immunoblotting (WB). ② In vitro study TGF-β 1 (10 ng/ml) was applied to stimulate human embryonic lung fibroblasts (HFL1) for 24 h and 48h, and p-JAK2 expression was detected by immunofluorescence. After HFL1 inoculation of culture plates, the control group, TGF-β 1 stimulation group, TGF-β 1+ LY2109761 (TGFβ-R1/2 inhibitor group, 0.5 mmol/L and 2 mmol/L) group, TGF-β 1+CEP (0.1 mmol/L and 1.0 mmol/L) group were co-incubated for 48 h, and the expression levels of TGFβ-R2, α-SMA, JAK2, and Col 1 were measured by WB. Comparisons between multiple groups were made by Tukey′s test, and comparisons between the two groups were analyzed by independent t-test. Results:① In vivo study, compared with the control group (1.45±0.04), joint swelling was increased at d13 [(2.54±0.16) in RA+PF+Vehicle group, t=16.02, P<0.001], and the mean arthritis index score and toe volume were decreased 3 days after CEP treatment(d16) [(2.89±0.11), t=5.78, P<0.001; (1.92±0.13), t=6.85, P<0.001]. For rats with pulmonary fibrosis, all had different degrees of lung enlargement, increased lung specific gravity, decreased Cst, and increased lung inflammation and fibrosis[(0.96±0.06), t=19.76, P<0.001; (0.26±0.09), t=17.64, P<0.001; (3.63±1.51), t=6.00, P<0.001; (1.75±0.71), t=5.84, P<0.001]. After CEP gavage, rats that had RA complicated with pulmonary fibrosis had reduced lung swelling, decreased lung specific gravity, increased Cst [(0.82±0.05), t=5.76, P<0.001; (0.43±0.18), t=2.31, P=0.038], and the scores of pulmonary fibrosis and inflammation [(3.00±1.00); (1.56±0.52)] all showed a trend of decrease, but did not reach statistical difference CEP inhibited the expression of TGF-β 1, TGFβ-R2, α-SMA, Fn and JAK2 in lung tissue of pulmonary fibrosis rats, and the differences among the five groups were statistically significant ( F=9.02, P=0.017; F=4.86, P=0.048; F=6.57, P=0.032; F=11.26, P=0.010; F=13.32, P=0.007). ② In vitro study, TGF-β 1 stimulated HFL1 showed stronger phosphorylated JAK2 (p-JAK2) fluorescent signal WB showed a significant increase in the expression of TGFβ-R2, α-SMA, JAK2 and Col1, and after LY and CEP intervention, the above proteins were reduced in a concentration-dependent manner, with statistically significant differences among all five groups ( F=337.30, P<0.001; F=20.61, P<0.001; F=100.60, P<0.001; F=180.90, P<0.001). Conclusion:JAK2 inhibitors can ameliorate RA-related pulmonary fibrosis, and the mechanism may be through interfering with the "crosstalk" between JAK2 and TGF-β 1 signaling pathway.