Salt-inducible kinase 2 (SIK2) inhibitor ARN-3236 attenuates bleomycin-induced pulmonary fibrosis in mice

Abstract

Background Pulmonary fibrosis is a fatal lung disease with complex pathogenesis and limited effective therapies. Salt-inducible kinase 2 (SIK2) is a kinase that phosphorylates CRTCs and regulates many physiological processes. However, the role of SIK2 on pulmonary fibrosis remains unclear, and whether SIK2 inhibitor can attenuate pulmonary fibrosis is unknown. Method We subjected human fetal lung fibroblasts (HFLs) to transforming growth factor-β1 (5 ng/mL) for 12 h, and examined the expression of SIK2, CRTCs and pCRTCs in fibroblasts by western-blot. To address the roles of SIK2 and CRTCs involved in the progression of pulmonary fibrosis, HFLs were treated with a small-molecule inhibitor ARN-3236 or by siRNA-mediated knockdown of SIK2 expression. Pulmonary fibrosis model was established with mice by exposing to bleomycin, and assessed by H&E and Masson’s trichrome staining. COL1A and α-SMA distributions were detected in lung tissues by immunohistochemical staining. Results We discovered that SIK2 and phosphorylated-CRTC2 were expressed at a low basal level in normal lung tissues and quiescent fibroblasts, but increased in fibrotic lung tissues and activated fibroblasts. Inhibition of SIK2 by ARN-3236 prevented the fibroblasts differentiation and extracellular matrix expression in HFLs and attenuated bleomycin-induced pulmonary fibrosis in mice. Mechanistically, inactivation of SIK2 resulted in the dephosphorylation and nuclear translocation of CRTC2. Within the nucleus, CRTC2 binds to CREB, promoting CREB-dependent anti-fibrotic actions. Conclusion In conclusion, our results elucidated a previously unexplored role of SIK2 in pulmonary fibrosis, and identified SIK2 as a new target for anti-fibrosis medicines.

The Promising Therapeutic Approaches for Radiation-Induced Pulmonary Fibrosis: Targeting Radiation-Induced Mesenchymal Transition of Alveolar Type II Epithelial Cells

“…It is likely that MyD88 (a key intracellular adapter for TLR signaling) prevents pulmonary fibrosis by regulating NF-κB activation to attenuate RILI ( Table 1 ) [ 105 ]. The SIK2 (salt-inducible kinase-2) inhibitor ARN-3236 was recently reported to attenuate bleomycin-induced pulmonary fibrosis in mice [ 106 ]. This gives us new candidate targets for a more comprehensive search for appropriate therapeutic approaches.…”

Salt-inducible kinase 2 regulates fibrosis during bleomycin-induced lung injury

“…We show here that nintedanib inhibits SIK2 with similar potency to its known tyrosine kinase targets both in vitro and in cells. Supporting a role for SIK2, a recent study has shown that a compound developed as an SIK inhibitor, ARN-3236, is able to attenuate bleomycin-induced lung fibrosis ( 63 ). ARN-3236 has selectivity for SIK2 over SIK1 and SIK3 with in vitro IC 50 values reported as <1, 21.6, and 6.6 nM, respectively ( 64 ).…”

Understanding the roles of salt-inducible kinases in cardiometabolic disease

“…However, whether the anti-fibrosis of dasatinib depends on SIKs is unclear. A recently study showed that SIK2 expression and activity is increased in fibrotic lung tissues and activated fibroblasts ( Zou et al, 2022 ). A selective SIK2 inhibitor ARN-3236 restricts fibroblasts differentiation and ECM gene expression in human fetal lung fibroblasts and attenuates bleomycin-induced pulmonary fibrosis in mice ( Zou et al, 2022 ), supporting as pathological role for SIK2 in pulmonary fibrosis.…”