Université de Paris, Institut Cochin, INSERM U1016 CNRS UMR8104, Paris, 75014, France.
UMR_S 999 "Pulmonary Hypertension: Pathophysiology and Novel Therapies", INSERM, Hôpital Marie Lannelongue, Le Plessis-Robinson, France.
Arthritis Res Ther. 2023 Sep 12;25(1):167. doi: 10.1186/s13075-023-03143-2.
Uncontrolled T-cell activation plays a key role in systemic sclerosis (SSc). Arsenic trioxide (ATO) has immunological effects and has demonstrated potential in preclinical SSc models. In this study, we assessed the efficacy of ATO in Fra2 transgenic (Fra2) mice, which develop severe vascular remodeling of pulmonary arterioles and nonspecific interstitial pneumonia-like lung disease, closely resembling human SSc-associated pulmonary hypertension, therefore partially resembling to the SSc human disease.
The efficacy of ATO in Fra2 mice was evaluated through histological scoring and determination of cell infiltration. Fibrotic changes in the lungs were assessed by measuring collagen content biochemically, using second harmonic generation to measure fibrillar collagen, and imaging via computed tomography. Cardiovascular effects were determined by measuring right ventricular systolic pressure and vessel remodeling. The mechanism of action of ATO was then investigated by analyzing lung cell infiltrates using flow cytometry and bulk RNA with sequencing techniques.
After ATO treatment, the Ashcroft histological score was substantially decreased by 33% in ATO-treated mice compared to control mice. Other investigations of fibrotic markers showed a trend of reduction in various measurements of fibrosis, but the differences did not reach significance. Further cardiovascular investigations revealed convergent findings supporting a beneficial effect of ATO, with reduced right ventricular systolic pressure and medial wall thickness, and a significant decrease in the number of muscularized distal pulmonary arteries in ATO-treated Fra2 mice compared to untreated Fra2 mice. Additionally, inflammatory cell infiltration was also markedly reduced in lesioned lungs. A reduction in the frequency of CD4 + and T effector memory cells, and an increase in the percentage of CD4 + T naive cells in the lungs of ATO-treated Fra-2 mice, was observed when compared to PBS group Fra-2 mice. RNA-seq analysis of ATO-treated mouse lungs revealed a downregulation of biological pathways associated with immune activity and inflammation, such as T-cell activation, regulation of leucocyte activation, leucocyte cell-cell adhesion, and regulation of lymphocyte activation.
Our results suggest the clinical relevance of ATO treatment in SSc. Using the Fra2 mouse model, we observed significant lung histological changes, a trend towards a decrease in various fibrotic makers, and a strong reduction in vascular remodeling. The mechanism of action of ATO appears to involve a marked counteraction of the immune activation characteristic of SSc, particularly T-cell involvement. These findings pave the way for further studies in SSc.
未受控制的 T 细胞激活在系统性硬化症（SSc）中起着关键作用。三氧化二砷（ATO）具有免疫作用，并已在 SSc 的临床前模型中显示出潜力。在这项研究中，我们评估了 ATO 在 Fra2 转基因（Fra2）小鼠中的疗效，Fra2 小鼠会发展出严重的肺小动脉血管重塑和非特异性间质性肺炎样肺部疾病，与人类 SSc 相关的肺动脉高压非常相似，因此部分类似于 SSc 人类疾病。
通过组织学评分和细胞浸润的测定来评估 ATO 在 Fra2 小鼠中的疗效。通过生化方法测量胶原蛋白含量、使用二次谐波产生来测量纤维胶原以及通过计算机断层扫描来评估肺部的纤维化变化。通过测量右心室收缩压和血管重塑来确定心血管效应。然后通过流式细胞术和批量 RNA 测序技术分析肺细胞浸润来研究 ATO 的作用机制。
与对照组相比，ATO 治疗后 Fra2 小鼠的 Ashcroft 组织学评分降低了 33%。对其他纤维化标志物的研究表明，各种纤维化测量值都有降低的趋势，但差异没有达到显著水平。进一步的心血管研究也支持 ATO 的有益作用，ATO 治疗的 Fra2 小鼠的右心室收缩压和中膜厚度降低，并且肌性远端肺动脉的数量显著减少。此外，病变肺部的炎症细胞浸润也明显减少。与 PBS 组 Fra2 小鼠相比，ATO 治疗的 Fra-2 小鼠肺部的 CD4+和 T 效应记忆细胞频率降低，CD4+T 幼稚细胞的比例增加。ATO 治疗的 Fra-2 小鼠肺组织的 RNA-seq 分析显示，与免疫活性和炎症相关的生物学途径（如 T 细胞激活、白细胞激活的调节、白细胞细胞-细胞黏附以及淋巴细胞激活的调节）下调。
我们的研究结果表明 ATO 治疗在 SSc 中的临床相关性。使用 Fra2 小鼠模型，我们观察到明显的肺部组织学变化，各种纤维化标志物有降低的趋势，以及血管重塑的强烈减少。ATO 的作用机制似乎涉及对 SSc 特征性免疫激活的显著拮抗作用，特别是 T 细胞的参与。这些发现为 SSc 的进一步研究铺平了道路。
