Streptococcus pneumoniae is a leading cause of community-acquired pneumonia. Intercellular adhesion molecule-1 (ICAM-1) is an adhesion molecule that is highly expressed on the pulmonary capillary endothelium, alveolar epithelium, and other cell types within the lung. ICAM-1 plays important roles in leukocyte adhesion, migration, and motility. To determine the contributions of ICAM-1 to bacterial clearance and leukocyte kinetics during pneumonia, mice were inoculated with S. pneumoniae and evaluated 1, 4, and 7 days later. Our results show that Icam1(-/-) mice have a greater number of viable bacteria within the lung at each time point. The impaired clearance observed in Icam1(-/-) mice was not due to an impediment in leukocyte recruitment. In fact, Icam1(-/-) mice had a greater number of neutrophils and recruited inflammatory macrophages in the lung tissue and the alveoli/airways on day 7. In contrast, fewer alveolar macrophages were present in the bronchoalveolar lavage (BAL) of Icam1(-/-) mice. The loss of body weight and the concentrations of inflammatory mediators in the BAL were also significantly greater in Icam1(-/-) mice. Mechanistic studies to understand the defect in clearance show that neutrophils and macrophage subpopulations had no defect in phagocytosis or acidification of phagosomes. RNA sequencing reveals many differences in gene expression but no suggestion of a defect in phagocytosis or killing. Thus, ICAM-1 is necessary for the clearance of S. pneumoniae and for the resolution of pneumonia but is not required for the recruitment of neutrophils or inflammatory macrophages into the pneumonic lung parenchyma or the alveoli/airways during S. pneumoniae-induced pneumonia.NEW & NOTEWORTHY Streptococcus pneumoniae is the leading cause of community-acquired pneumonia. Our study examined ICAM-1, an adhesion molecule that is expressed on most cell types and plays important roles in leukocyte adhesion, migration, and motility. The data demonstrate that ICAM-1 is necessary for the clearance of S. pneumoniae and for the resolution of pneumonia but is not required for the recruitment of neutrophils or inflammatory macrophages into the pneumonic lung parenchyma or the alveoli/airways.
Leukocyte kinetics and bacterial clearance during Streptococcus pneumoniae pneumonia and contributions of ICAM-1.
阅读:3
作者:McPeek Matthew K, Gomez John C, Martin Jessica R, Iannone Marie Anne, Dang Hong, Doerschuk Claire M
期刊: | American Journal of Physiology-Lung Cellular and Molecular Physiology | 影响因子: | 3.500 |
时间: | 2025 | 起止号: | 2025 Jan 1; 328(1):L41-L59 |
doi: | 10.1152/ajplung.00039.2024 |
特别声明
1、本文转载旨在传播信息,不代表本网站观点,亦不对其内容的真实性承担责任。
2、其他媒体、网站或个人若从本网站转载使用,必须保留本网站注明的“来源”,并自行承担包括版权在内的相关法律责任。
3、如作者不希望本文被转载,或需洽谈转载稿费等事宜,请及时与本网站联系。
4、此外,如需投稿,也可通过邮箱info@biocloudy.com与我们取得联系。