Anti-fibrotic Effects of IN-1130, a Transforming Growth Factor β1 Type I Receptor Kinase (ALK5) Inhibitor, on Pulmonary Fibrosis

Abstract

Transforming growth factor β1 (TGF-β1) 는 다양한 생물학적 활동을 조절하는 cytokine으로 세포 외 기질의 축적으로 발생되는 조직 섬유증의 주요 조절인자로 알려져 있다. 섬유증은 간, 폐, 신장 등에서 수십 년에 걸쳐 진행, 유발된다. 따라서 병적인 상태에서 나타나는 TGF-β1의 과잉 신호전달 체계를 억제할 수 있는 약물의 개발이 시급하나 실제로 아직까지 실험 단계에 놓여져 있다. 본 연구에서는 ALK 5억제제인 IN-1130의 항 섬유증 효과를 알아보기 위해 블레오마이신 또는 TGF-β1 바이러스로 유도된 두 가지 폐 섬유증 동물 모델에서 진행하였다. 블레오마이신으로 유도된 폐 섬유증 동물 모델에서 TGF-β1의 type I 수용체인 ALK5를 억제하는 기전으로 섬유증을 치료하는 새롭게 합성된 IN-1130 (15 또는 25 또는 50 mg/kg)의 효과를 테스트 하였다. 또한 항 염증작용을 가진 덱사메타손을 함께 투여하였다. 블레오마이신을 주입한 mice의 폐에서 PCR, western blotting, hematoxylin/eosin 염색법 그리고 α-SMA를 이용한 면역 염색의 실험법을 통해 섬유증의 지표를 측정하였다. IN-1130의 투여는 생존율을 개선시키고 조직학적인 변화도 개선시켰다. IN-1130은 또한 α-SMA, PCNA 단백질과 fibronectin mRNA의 발현 정도를 유의적으로 감소시켰다. 이 결과들은 IN-1130 단독 투여가 블레오마이신으로 유도된 폐 섬유증에 효과가 있다는 것을 나타낸다. IN-1130은 TGF-β1 바이러스에 의해 유도된 폐 섬유증에서도 실험되어졌다. IN-1130은 TGF-β1바이러스를 주입하고 7일간 투여되었고 TGF-β1바이러스를 주입 후 7일, 14일, 21일 후 시험했다. 투여는 생존율을 개선시키고 조직학적인 변화도 개선시켰다. IN-1130 (25 or 50mg/kg)를 투여한 AdTGF-β mice의 α-SMA 와 p-Smad2/3, fibronectin mRNA수치는 감소되었다. TGF-β 바이러스에 의해 증가된 PCNA는 IN-1130 (25mg/kg) 의해 감소되었다. 이 결과들을 볼 때 IN-1130은 AdTGF-β 의해 유도된 폐 섬유증 치료제로서 효과를 가지고 있다. 결론적으로 ALK 5 억제제인 IN-1130은 블레오마이신 또는 TGF-β1 바이러스에 의해 유도된 폐 섬유증을 치료하는 효과를 가지고 있다.;The transforming growth factor (TGF)-β1 is a key mediator of extracelluar matrix accumulation leading to tissue fibrosis. There is great interest in development of specific small molecular inhibitor of TGF-β1 signaling via type Ⅰ receptor kinase known as an activin receptor like kinase (ALK) 5, however, therapeutic agents remain at an experimental stage. The purpose of this study is to investigate anti-fibrotic effects of a newly developed ALK5 small molecule inhibitor (IN-1130) in in vivo animal models of pulmonary fibrosis. Two pulmonary fibrosis animal models were induced by intratracheal injections of bleomycin or adenovector-mediated TGF-β1 gene (AdTGF-β1) to mice. In bleomycin-induced pulmonary fibrosis, , surviving mice were treated intraperitoneally with IN-1130 alone (15, 25 or 50 mg/kg) or combination of IN-1130 (50 mg/kg) with dexamethasone (4 mg/kg) once a day during next 4 weeks (week 5-week 8) following 4 weeks after bleomycin-injection. At the end of week 8, morphology and typical biomarkers of fibrosis were assayed by hematoxylin/eosin staining, immunostaining polymerase chain reaction and western blotting. The survival rates of mice was improved by intraperitoneal treatment of IN-1130 and IN-1130 decreased the abnormal histological characteristics, such as thickening alveolar septa, collapsing of alveolar spaces which are typically seen in fibrotic lung tissues. IN-1130 also significantly reduced the expression levels of α-SMA protein, proliferation cell nuclear antigen (PCNA) protein and fibronectin mRNA increased by bleomycin injection. Combination of IN-1130 with dexamethasone decreased the expression levels of PCNA and fibronectin similarly to PBS-injected control level. These results indicate IN-1130 alone produces effective anti-fibrotic effects in bleomycin-induced pulmonary fibrosis. In AdTGF-β1-induced pulmonary fibrosis, drugs were intraperitoneally administrated to mice once day for next 7 days after AdTGF-β1 injection and some fibrotic markers and morphology were examined at 7, 14 and 21 days after AdTGF-β1 injection. Treatment of IN-1130 (50 mg/kg) in AdTGF-β1-injected mice decreased the α-SMA and p-Samd2/3 proteins expression levels. Fibronectin mRNA level expression increased by AdTGF-β1 injection was significantly decreased by IN-1130 (25 or 50 mg/kg) at 7, 14 and 21 days after drug treatment of IN-1130 (25 or 50 mg/kg). The increased PCNA level by AdTGF-β1 injection was also inhibited by IN-1130 25mg/kg. These results indicate that IN-1130 has an anti-fibrotic effect in AdTGF-β1-induced pulmonary fibrosis. In conclusion, the novel ALK 5 inhibitor IN-1130 effectively suppresses pulmonary fibrosis induced by either bleomycin or AdTGF-β1 and therefore has high potential to be developed as a new anti-fibrotic agent.