关键词: Aeromonas hydrophila (A. hydrophila) Cyprinus carpio bacteria cytokines engulfment inflammation red blood cell (RBC) teleost fish

Mesh : Animals Carps / immunology microbiology Erythrocytes / immunology metabolism Cytokines / metabolism immunology Aeromonas hydrophila / immunology Gram-Negative Bacterial Infections / immunology Fish Diseases / immunology microbiology Phagocytosis / immunology Pathogen-Associated Molecular Pattern Molecules / immunology Immunity, Innate

来  源:   DOI:10.3389/fimmu.2024.1407237   PDF(Pubmed)

Abstract:
UNASSIGNED: Red blood cells (RBCs), also known as erythrocytes, are underestimated in their role in the immune system. In mammals, erythrocytes undergo maturation that involves the loss of nuclei, resulting in limited transcription and protein synthesis capabilities. However, the nucleated nature of non-mammalian RBCs is challenging this conventional understanding of RBCs. Notably, in bony fishes, research indicates that RBCs are not only susceptible to pathogen attacks but express immune receptors and effector molecules. However, given the abundance of RBCs and their interaction with every physiological system, we postulate that they act in surveillance as sentinels, rapid responders, and messengers.
UNASSIGNED: We performed a series of in vitro experiments with Cyprinus carpio RBCs exposed to Aeromonas hydrophila, as well as in vivo laboratory infections using different concentrations of bacteria.
UNASSIGNED: qPCR revealed that RBCs express genes of several inflammatory cytokines. Using cyprinid-specific antibodies, we confirmed that RBCs secreted tumor necrosis factor alpha (TNFα) and interferon gamma (IFNγ). In contrast to these indirect immune mechanisms, we observed that RBCs produce reactive oxygen species and, through transmission electron and confocal microscopy, that RBCs can engulf particles. Finally, RBCs expressed and upregulated several putative toll-like receptors, including tlr4 and tlr9, in response to A. hydrophila infection in vivo.
UNASSIGNED: Overall, the RBC repertoire of pattern recognition receptors, their secretion of effector molecules, and their swift response make them immune sentinels capable of rapidly detecting and signaling the presence of foreign pathogens. By studying the interaction between a bacterium and erythrocytes, we provide novel insights into how the latter may contribute to overall innate and adaptive immune responses of teleost fishes.
摘要:
红细胞(RBC),也被称为红细胞,在免疫系统中的作用被低估了.在哺乳动物中,红细胞经历成熟,涉及细胞核的丧失,导致有限的转录和蛋白质合成能力。然而,非哺乳动物红细胞的成核性质正在挑战这种对红细胞的常规理解。值得注意的是,在骨鱼中,研究表明,红细胞不仅容易受到病原体的攻击,而且表达免疫受体和效应分子。然而,考虑到红细胞的丰富及其与每个生理系统的相互作用,我们假设他们作为哨兵进行监视,快速反应者,和信使。
我们对暴露于嗜水气单胞菌的鲤鱼红细胞进行了一系列体外实验,以及在体内实验室感染使用不同浓度的细菌。
qPCR显示红细胞表达几种炎性细胞因子的基因。使用鲤科动物特异性抗体,我们证实红细胞分泌肿瘤坏死因子α(TNFα)和干扰素γ(IFNγ)。与这些间接免疫机制相反,我们观察到红细胞产生活性氧,通过透射电子和共聚焦显微镜,红细胞可以吞噬颗粒。最后,红细胞表达和上调几种推定的toll样受体,包括tlr4和tlr9,以响应体内嗜水菌感染。
总的来说,模式识别受体的红细胞库,它们分泌效应分子,它们的快速反应使它们具有免疫前哨,能够快速检测并发出外来病原体的信号。通过研究细菌和红细胞之间的相互作用,我们提供了新的见解,后者可能有助于整体先天和适应性免疫反应的硬骨鱼。
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