Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.
The Veterans Affairs Medical Center, Cincinnati, Ohio, USA.
mBio. 2024 Aug 14;15(8):e0140924. doi: 10.1128/mbio.01409-24. Epub 2024 Jul 2.
pneumonia (PjP) poses a serious risk to individuals with compromised immune systems, such as individuals with HIV/AIDS or undergoing immunosuppressive therapies for cancer or solid organ transplants. Severe PjP triggers excessive lung inflammation, resulting in lung function decline and consequential alveolar damage, potentially culminating in acute respiratory distress syndrome. Non-HIV patients face a 30%-60% mortality rate, emphasizing the need for a deeper understanding of inflammatory responses in PjP. Prior research emphasized macrophages in infections, neglecting neutrophils' role in tissue damage. Consequently, the overemphasis on macrophages led to an incomplete understanding of the role of neutrophils and inflammatory responses. In the current investigation, our RNAseq studies on a murine surrogate model of PjP revealed heightened activation of the NLRP3 inflammasome and NETosis cell death pathways in their lungs. Immunofluorescence staining confirmed neutrophil extracellular trap (NET) presence in the lungs of the -infected mice, validating our findings. Moreover, isolated neutrophils exhibited NETosis when directly stimulated with . Isolated NETs compromised viability , highlighting the potential role of neutrophils in controlling fungal growth and promoting inflammation during pneumonia through NLRP3 inflammasome assembly and NETosis. These pathways, essential for inflammation and pathogen elimination, bear the risk of uncontrolled activation leading to excessive tissue damage and persistent inflammation. This pioneering study is the first to identify the formation of NETs and inflammasomes during infection, paving the way for comprehensive investigations into treatments aimed at mitigating lung damage and augmenting survival rates for individuals with .IMPORTANCE pneumonia (PjP) affects individuals with weakened immunity, such as HIV/AIDS, cancer, and organ transplant patients. Severe PjP triggers lung inflammation, impairing function and potentially causing acute respiratory distress syndrome. Non-HIV individuals face a 30%-60% mortality rate, underscoring the need for deeper insight into PjP's inflammatory responses. Past research focused on macrophages in managing infection and its inflammation, while the role of neutrophils was generally overlooked. In contrast, our findings in -infected mouse lungs showed neutrophil involvement during inflammation and increased expression of NLRP3 inflammasome and NETosis pathways. Detection of neutrophil extracellular traps further indicated their involvement in the inflammatory process. Although beneficial in combating infection, unregulated neutrophil activation poses a potential threat to lung tissues. Understanding the behavior of neutrophils in infections is crucial for controlling detrimental reactions and formulating treatments to reduce lung damage, ultimately improving the survival rates of individuals with PjP.
肺炎(PjP)对免疫系统受损的个体构成严重威胁,如 HIV/AIDS 患者或正在接受癌症或实体器官移植免疫抑制治疗的患者。严重的 PjP 会引发过度的肺部炎症,导致肺功能下降和肺泡损伤,最终可能导致急性呼吸窘迫综合征。非 HIV 患者的死亡率为 30%-60%,这强调了需要更深入了解 PjP 中的炎症反应。先前的研究强调了巨噬细胞在真菌感染中的作用,而忽视了中性粒细胞在组织损伤中的作用。因此,对巨噬细胞的过分强调导致了对中性粒细胞和炎症反应作用的不完全理解。在当前的研究中,我们对 PjP 的小鼠替代模型进行的 RNAseq 研究表明,其肺部的 NLRP3 炎性小体和 NETosis 细胞死亡途径的激活程度更高。免疫荧光染色证实了感染小鼠肺部存在中性粒细胞胞外陷阱(NET),验证了我们的发现。此外,当直接用刺激分离的中性粒细胞时,它们表现出 NETosis。分离的 NET 损害了细胞活力,突出了中性粒细胞在控制真菌感染和通过 NLRP3 炎性小体组装和 NETosis 促进炎症过程中的潜在作用。这些途径对于炎症和病原体清除至关重要,但存在过度激活导致过度组织损伤和持续炎症的风险。这项开创性的研究首次确定了 NETs 和炎性小体在真菌感染过程中的形成,为旨在减轻肺部损伤和提高真菌感染患者生存率的治疗方法的全面研究铺平了道路。