Dipartimento di Medicina dei Sistemi, Università Tor Vergata, Rome, Italy.
Dipartimento di Biomedicina e Prevenzione, Università Tor Vergata, Rome, Italy.
Inflamm Bowel Dis. 2018 May 18;24(6):1213-1224. doi: 10.1093/ibd/izy062.
In Crohn's disease (CD), the pathogenic immune response is associated with high Smad7, an inhibitor of TGF-β1 signaling. Smad7 knockdown with Mongersen, a specific antisense oligonucleotide-containing compound, restores TGF-β1 activity leading to inhibition of inflammatory signals and associates with clinical benefit in CD patients. As TGF-β1 is pro-fibrogenic, it remains unclear whether Mongersen-induced Smad7 inhibition increases the risk of intestinal fibrosis. We assessed the impact of Smad7 inhibition on the course of colitis-driven intestinal fibrosis in mice.
BALB/c mice were rectally treated with increasing doses of trinitrobenzene sulfonic acid (TNBS) for 8 or 12 weeks. The effect of oral Smad7 antisense or control oligonucleotide, administered to mice starting from week 5 or week 8, respectively, on mucosal inflammation and colitis-associated colonic fibrosis was assessed. Mucosal samples were analyzed for Smad7 by immunoblotting and immunohistochemistry, TGF-β1 by enzyme-linked immunosorbent assay, and collagen by immunohistochemistry.
TNBS-induced chronic colitis was associated with colonic deposition of collagen I and fibrosis, which were evident at week 8 and became more pronounced at week 12. TNBS treatment enhanced Smad7 in both colonic epithelial and lamina propria mononuclear cells. Colitic mice treated with Smad7 antisense oligonucleotide exhibited reduced signs of colitis, less collagen deposition, and diminished fibrosis. These findings were associated with diminished synthesis of TGF-β1 and reduced p-Smad3 protein expression.
Attenuation of colitis with Smad7 antisense oligonucleotide limits development of colonic fibrosis.
在克罗恩病（CD）中，致病免疫反应与高表达的 Smad7 相关，Smad7 是 TGF-β1 信号通路的抑制剂。用蒙格鲁生（一种含有特定反义寡核苷酸的化合物）敲低 Smad7 可恢复 TGF-β1 活性，从而抑制炎症信号，并与 CD 患者的临床获益相关。由于 TGF-β1 具有促纤维化作用，因此尚不清楚蒙格鲁生诱导的 Smad7 抑制是否会增加肠道纤维化的风险。我们评估了 Smad7 抑制对小鼠结肠炎驱动的肠道纤维化过程的影响。
BALB/c 小鼠通过直肠给予不同剂量的三硝基苯磺酸（TNBS）处理 8 或 12 周。分别从第 5 周或第 8 周开始给予口服 Smad7 反义或对照寡核苷酸，评估其对黏膜炎症和结肠炎相关结肠纤维化的影响。通过免疫印迹和免疫组织化学分析黏膜样本中的 Smad7，通过酶联免疫吸附试验分析 TGF-β1，通过免疫组织化学分析胶原蛋白。
TNBS 诱导的慢性结肠炎与结肠 I 型胶原和纤维化的沉积相关，这些在第 8 周时已经明显，并在第 12 周时更加明显。TNBS 处理增强了结肠上皮和固有层单核细胞中的 Smad7。用 Smad7 反义寡核苷酸处理的结肠炎小鼠表现出较轻的结肠炎迹象、较少的胶原沉积和较轻的纤维化。这些发现与 TGF-β1 合成减少和 p-Smad3 蛋白表达降低有关。
Smad7 反义寡核苷酸减轻结肠炎可限制结肠纤维化的发展。
