白细胞介素-21及其受体(IL-21/IL-21R)加重衣原体肺部感染,而巨噬细胞(Mφ)是衣原体感染的主要细胞之一,也是炎性细胞因子的主要来源。因此,研究IL-21/IL-21R是否通过调节Mφ加重衣原体呼吸道感染尤为重要。结合生物信息学分析,我们建立了小鼠衣原体IL-21R缺陷(IL-21R-/-)模型(C.muridarum)体内呼吸道感染,通过在体外添加rmIL-21研究了鼠尾草刺激的RAW264.7,并进行过继转移实验,以阐明IL-21/IL-21R与Mφ之间的关联。IL-21R-/-小鼠肺总Mφ浸润降低,肺泡巨噬细胞,和间质巨噬细胞与感染后的WT小鼠相比。转录组分析表明,M1相关基因在IL-21R-/-小鼠中下调,并且IL-21R缺陷会影响Mφ介导的炎症反应。体内实验证实,在IL-21R-/-小鼠中,肺M1型CD80+,CD86+,MHCII+,TNFα+,iNOS+Mφ下降,虽然M2型CD206+没有差异,TGF-β+,IL-10+和ARG1+Mφ。体外,rmIL-21对小鼠C.muridarum刺激的RAW264.7细胞的给药促进iNOS-NO的水平以及IL-12p40和TNFα的表达,但对TGFβ或IL-10无影响。Further,来自IL-21R-/-小鼠的M1样骨髓源性巨噬细胞的过继转移,与WT小鼠不同,有效地保护受者免受小鼠C.muridarum感染,并引起肺部病理缓解。这些发现有助于理解IL-21/IL-21R通过促进Mφ的促炎作用而加剧衣原体呼吸道感染的机制。
Interleukin-21 and its receptors (IL-21/IL-21R) aggravate chlamydial lung infection, while macrophages (Mφ) are one of the main cells infected by chlamydia and the main source of inflammatory cytokines. Therefore, it is particularly important to study whether IL-21/IL-21R aggravates chlamydia respiratory infection by regulating Mφ. Combined with bioinformatics analysis, we established an IL-21R-deficient (IL-21R-/-) mouse model of Chlamydia muridarum (C. muridarum) respiratory tract infection in vivo, studied C. muridarum-stimulated RAW264.7 by the addition of rmIL-21 in vitro, and conducted adoptive transfer experiments to clarify the association between IL-21/IL-21R and Mφ. IL-21R-/- mice showed lower infiltration of pulmonary total Mφ, alveolar macrophages, and interstitial macrophages compared with WT mice following infection. Transcriptomic analysis suggested that M1-related genes are downregulated in IL-21R-/- mice and that IL-21R deficiency affects the Mφ-mediated inflammatory response during C. muridarum infection. In vivo experiments verified that in IL-21R-/- mice, pulmonary M1-type CD80+, CD86+, MHC II+, TNFα+, and iNOS+ Mφ decreased, while there were no differences in M2-type CD206+, TGF-β+, IL-10+ and ARG1+ Mφ. In vitro, administration of rmIL-21 to C. muridarum-stimulated RAW264.7 cells promoted the levels of iNOS-NO and the expression of IL-12p40 and TNFα, but had no effect on TGFβ or IL-10. Further, adoptive transfer of M1-like bone marrow-derived macrophages derived from IL-21R-/- mice, unlike those from WT mice, effectively protected the recipients against C. muridarum infection and induced relieved pulmonary pathology. These findings help in understanding the mechanism by which IL-21/IL-21R exacerbates chlamydia respiratory infection by promoting the proinflammatory effect of Mφ.