Sanderford Victoria, Barna Barbara P, Barrington Robert A, Malur Anagha, Mohan Arjun, Leffler Nancy, Soliman Eman, Thomassen Mary Jane
Program in Lung Cell Biology and Translational Research, Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Brody School of Medicine, East Carolina University, Greenville, NC, USA.
Department of Microbiology and Immunology, University of South Alabama, Mobile, AL, USA.
J Nanomed Nanotechnol. 2020;11(1). doi: 10.35248/2157-7439.20.11.541. Epub 2020 Feb 18.
The pathological consequences of interaction between environmental carbon pollutants and microbial antigens have not been fully explored. We developed a murine model of multi-wall carbon nanotube (MWCNT)-elicited granulomatous disease which bears a striking resemblance to sarcoidosis, a human granulomatous disease. Because of reports describing lymphocyte reactivity to mycobacterial antigens in sarcoidosis patients, we hypothesized that addition of mycobacterial antigen (ESAT-6) to MWCNT might elicit activation in T cells.
Macrophage-specific peroxisome-proliferator-activated receptor gamma (PPARγ) knock out (KO) mice were studied along with wild-type mice because our previous report indicated PPARγ deficiency in sarcoidosis alveolar macrophages. MWCNT+ESAT-6 were instilled into mice. Controls received vehicle (surfactant-PBS) or ESAT-6 and were evaluated 60 days post-instillation. As noted in our recent publication, lung tissues from PPARγ KO mice instilled with MWCNT+ESAT-6 yielded more intensive pathophysiology, with elevated fibrosis.
Inspection of mediastinal lymph nodes (MLN) revealed no granulomas but deposition of MWCNT. MLN cell counts were higher in PPARγ KO than in wild-type instilled with MWCNT+ESAT-6. Moreover, the CD4:CD8 T cell ratio, a major clinical metric for human disease, was increased in PPARγ KO mice. Bronchoalveolar lavage (BAL) cells from PPARγ KO mice instilled with MWCNT+ESAT-6 displayed increased Th17 cell markers (RORγt, IL-17A, CCR6) which associate with elevated fibrosis.
These findings suggest that PPARγ deficiency in macrophages may promote ESAT-6-associated T cell activation in the lung, and that the MWCNT+ESAT-6 model may offer new insights into pathways of lymphocyte-mediated sarcoidosis histopathology.
环境碳污染物与微生物抗原相互作用的病理后果尚未得到充分研究。我们建立了一种多壁碳纳米管（MWCNT）诱发的肉芽肿性疾病小鼠模型，该模型与人类肉芽肿性疾病结节病极为相似。由于有报道描述结节病患者淋巴细胞对分枝杆菌抗原的反应性，我们推测向MWCNT中添加分枝杆菌抗原（ESAT-6）可能会引发T细胞活化。
研究了巨噬细胞特异性过氧化物酶体增殖物激活受体γ（PPARγ）敲除（KO）小鼠和野生型小鼠，因为我们之前的报告表明结节病肺泡巨噬细胞中存在PPARγ缺乏。将MWCNT+ESAT-6注入小鼠体内。对照组接受载体（表面活性剂-PBS）或ESAT-6，并在注入后60天进行评估。正如我们最近发表的文章中所指出的，注入MWCNT+ESAT-6的PPARγ KO小鼠的肺组织产生了更严重的病理生理学变化，纤维化程度升高。
对纵隔淋巴结（MLN）的检查未发现肉芽肿，但有MWCNT沉积。注入MWCNT+ESAT-6的PPARγ KO小鼠的MLN细胞计数高于野生型小鼠。此外，人类疾病的主要临床指标CD4:CD8 T细胞比值在PPARγ KO小鼠中增加。注入MWCNT+ESAT-6的PPARγ KO小鼠的支气管肺泡灌洗（BAL）细胞显示Th17细胞标志物（RORγt、IL-17A、CCR6）增加，这些标志物与纤维化程度升高有关。
这些发现表明，巨噬细胞中的PPARγ缺乏可能促进肺中ESAT-6相关的T细胞活化，并且MWCNT+ESAT-6模型可能为淋巴细胞介导的结节病组织病理学途径提供新的见解。
