Apremilast reverses the profibrotic phenotype of dermal fibroblasts derived from patients with systemic sclerosis and prevents the progression of bleomycin-induced dermal fibrosis in mice

Abstract

Abstract Phosphodiesterase (PDE) 4 inhibitors have been reported to suppress the progression of dermal fibrosis in patients with systemic sclerosis (SSc); however, the precise mechanisms remain to be elucidated. Therefore, we conducted experiments focusing on the antifibrotic and anti-inflammatory effects of apremilast using dermal fibroblasts derived from patients with SSc and an SSc mouse model. Dermal fibroblasts derived from healthy controls and patients with SSc were incubated with apremilast in the presence or absence of 10 ng/ml transforming growth factor (TGF)-β1 for the measurement of intracellular cAMP levels and evaluation of mRNA and protein expression. A bleomycin-induced skin fibrosis mouse model was used to evaluate the inhibitory effects of apremilast on the progression of dermal fibrosis. Intracellular cAMP levels were significantly reduced in dermal fibroblasts derived from patients with SSc compared with those derived from healthy controls. Apremilast reduced the mRNA expression of COL1A1, COL1A2, CTGF, and ACTA2 and the protein expression of type I collagen and Cellular Communication Network Factor 2 (CCN2) in dermal fibroblasts. Additionally, apremilast inhibited the progression of dermal fibrosis in mice, partly by acting on macrophages. These results suggest that apremilast may be a potential candidate for treating dermal fibrosis in SSc.