Experimental Radiology, Department of Radiology and Nuclear Medicine, Otto von Guericke University, Magdeburg, Germany.
Department of Trauma, Hand and Reconstructive Surgery, University Hospital Frankfurt, Germany.
J Immunol Res. 2021 Jan 28;2021:6647753. doi: 10.1155/2021/6647753. eCollection 2021.
Recently, identification of immunosuppressive polymorphonuclear leukocytes (PMNL) that were traditionally described as proinflammatory cells emerged in the field of posttraumatic immunity. To understand their local and remote distribution after trauma, PMNL-subsets and the impact of immunomodulatory Club Cell protein (CC)16 that correlates with pulmonary complications were assessed.
C57BL/6N mice were divided into three groups, receiving isolated blunt chest trauma (TxT), undergoing TxT followed by cecal ligation and puncture (CLP, TxT + CLP) after 24 h, or sham undergoing analgosedation ( = 18/group). Further, each group was subdivided into three groups receiving either no treatment (ctrl) or intratracheal neutralization of CC16 by application of anti-CC16-antibody or application of an unspecific IgG control antibody ( = 6/group). Treatment was set at the time point after TxT. Analyses followed 6 h post-CLP. PMNL were characterized via expression of CD11b, CD16, CD45, CD62L, and Ly6G by flow cytometry in bone marrow (BM), blood, spleen, lung, liver, and bronchoalveolar and peritoneal lavage fluid (BALF and PL). Apoptosis was assessed by activated (cleaved) caspase-3. Results from untreated ctrl and IgG-treated mice were statistically comparable between all corresponding sham, TxT, and TxT + CLP groups.
Immature (CD16CD62L) PMNL increased significantly in BM, circulation, and spleen after TxT . sham and were significantly attenuated in the lungs, BALF, PL, and liver. Classical-shaped (CD16CD62L) PMNL increased after TxT . sham in peripheral tissue and were significantly attenuated in circulation, proposing a trauma-induced migration of mature or peripheral differentiation of circulating immature PMNL. Immunosuppressive (CD16CD62L) PMNL decreased significantly in the lungs and spleen, while they systemically increased after TxT . sham. CLP in the TxT + CLP group reduced immunosuppressive PMNL in PL and increased their circulatory rate . isolated TxT, showing local reduction in affected tissue and their increase in nonaffected tissue. CC16 neutralization enhanced the fraction of immunosuppressive PMNL following TxT . sham and decreased caspase-3 in the lungs post-CLP in the TxT + CLP group, while apoptotic cells in the liver diminished post-TxT. Posttraumatic CC16 neutralization promotes the subset of immunosuppressive PMNL and antagonizes their posttraumatic distribution.
Since CC16 affects both the distribution of PMNL subsets and apoptosis in tissues after trauma, it may constitute as a novel target to beneficially shape the posttraumatic tissue microenvironment and homeostasis to improving outcomes.
最近，在创伤后免疫领域出现了传统上被描述为促炎细胞的免疫抑制性多形核白细胞（PMN）的鉴定。为了了解它们在创伤后的局部和远处分布，评估了PMN 亚群和与肺部并发症相关的免疫调节克拉细胞蛋白（CC）16 的影响。
将 C57BL/6N 小鼠分为三组，分别接受单纯性胸部钝挫伤（TxT）、TxT 后 24 小时行盲肠结扎和穿刺（CLP，TxT+CLP）或假手术（=18/组）。进一步，每组再分为三组，分别接受未治疗（ctrl）或经气管内应用抗 CC16 抗体中和 CC16 或应用非特异性 IgG 对照抗体（=6/组）。治疗时间设定在 TxT 后。在 CLP 后 6 小时进行分析。通过流式细胞术检测骨髓（BM）、血液、脾脏、肺、肝和支气管肺泡灌洗液（BALF）和腹腔灌洗液（PL）中 CD11b、CD16、CD45、CD62L 和 Ly6G 的表达来鉴定 PMNL。通过激活（切割）半胱天冬酶-3 评估细胞凋亡。未治疗的 ctrl 和 IgG 治疗组的结果在所有相应的 sham、TxT 和 TxT+CLP 组之间具有统计学可比性。
TxT 后，BM、循环和脾脏中的幼稚（CD16CD62L）PMN 显著增加。 sham，并在肺部、BALF、PL 和肝脏中显著减少。经典形状（CD16CD62L）PMNL 在 TxT 后外周组织中增加。 sham，并在循环中显著减少，提示创伤诱导成熟或循环中幼稚 PMNL 的外周分化。免疫抑制性（CD16CD62L）PMN 在肺和脾脏中显著减少，而在 TxT 后循环中系统增加。 sham。CLP 在 TxT+CLP 组中降低了 PL 中的免疫抑制性 PMNL，并增加了其循环速度。孤立的 TxT，显示受影响组织中的局部减少和非受影响组织中的增加。CC16 中和在 TxT 后增加了 sham 中的免疫抑制性 PMNL 亚群，并降低了 TxT+CLP 组中 CLP 后肺部的 caspase-3，同时减少了 TxT 后肝脏中的凋亡细胞。创伤后 CC16 中和促进免疫抑制性 PMNL 亚群，并拮抗其创伤后分布。
由于 CC16 影响创伤后 PMNL 亚群的分布和组织中的细胞凋亡，因此它可能成为有益地塑造创伤后组织微环境和内稳态以改善结果的新靶标。
