Objective  To explore the role and mechanisms of interferon regulatory factor 8 (IRF8) in the pathogenesis of acute lung injury (ALI).

Methods  Reverse transcrip-tion-quantitative polymerase chain reaction (RT-qPCR) and western blots (WB) were used to detect the expression of IRF8 protein and mRNA in models of lung injury both in vivo and in vitro. IRF8 stable overexpression and knockdown A549 cell lines were established in vitro, and the expression levels of inflammation-related genes at the transcriptional level were detected using RT-qPCR. WB analysis was employed to assess the expression of apopto-sis-related genes. Each group of 12 wild type (WT) mice and Irf8 knockout mice was selected to establish the model of ALI. Collect lung tissues from the modeled mice and weigh them. Bronchoalveolar lavage fluid (BALF) was collected and assessed for total cell count and total protein content. Hematoxylin-eosin (HE) staining and immunofluorescence (IF) analyses were performed to evaluate lung tissue inflammation infiltration. RT-qPCR was used to detect the mRNA expression of inflammation-related genes in the lung tissue of Irf8 knockout mice. The content of apoptosis in lung tissue was detected by TUNEL staining. In vivo and in vitro, the protein expression of ferroptosis-related signaling molecules was as-sessed by WB.

Results  The expression of IRF8 is upregulated both in mRNA and protein levels in ALI. IRF8 knockdown exacerbates intracellular inflammation and cell apoptosis in vitro. Conversely, IRF8 overexpression can exert a protective effect in vitro. Irf8 knockout further exacerbates lung injury in vivo. Mechanistically, IRF8 alleviates lung injury by regulating the expression of ferroptosis-related signaling molecules.

Conclusion  IRF8 exerts a protective role in lung injury by targeting ferroptosis, providing a potential target for the treatment of lung injury.

1.Bellani G, Laffey JG, Pham T, et al. Epidemiology, patterns of care, and mortality for patients with acute respiratory distress syndrome in intensive care units in 50 countries[J]. JAMA, 2016, 315(8): 788-800. DOI: 10.1001/jama.2016.0291.

2.Butt Y, Kurdowska A, Allen TC. Acute lung injury: a clinical and molecular review[J]. Arch Pathol Lab Med, 2016, 140(4): 345-50. DOI: 10.5858/arpa.2015-0519-RA.

3.Grotberg JC, Reynolds D, Kraft BD. Management of severe acute respiratory distress syndrome: a primer[J]. Crit Care, 2023, 27(1): 289. DOI: 10.1186/s13054-023-04572-w.

4.彭静, 李巧玲, 梅艳, 等. 基于CiteSpace的天然药物及中药治疗急性肺损伤机制研究中文文献可视化分析[J]. 药物流行病学杂志, 2023, 32(11): 1296-1304. [Peng J, Li QL, Mei Y, et al. Visual analysis of Chinese literature on the mechanism of natural drugs and traditional Chinese medicine in the treatment of acute lung injury based on CiteSpace[J]. Chinese Journal of Pharmacoepidemiology, 2023, 32(11): 1296-1304.] DOI: 10.19960/j.issn.1005-0698.202311013.

5.朱紫陌, 赵显芳, 崔白梅, 等. 云南民族药理肺散防治急性肺损伤的作用及网络药理学分析[J]. 中国药师, 2022, 25(11): 1914-1921. [Zhu ZM, Zhao XF, Cui BM, et  al. The effect of Yunnan ethnic pharmacology lung powder on the prevention and treatment of acute lung injury and network pharmacology analysis[J] Chinese Pharmacist, 2022, 25(11): 1914-1921.] DOI: 10.19962/j.cnki.issn1008-049X.2022.11.008.

6.Chiang HS, Liu HM. The molecular basis of viral inhibition of IRF- and STAT-dependent immune re-sponses[J]. Front Immunol, 2018, 9: 3086. DOI: 10.3389/fimmu.2018.03086.

7.Tamura T, Yanai H, Savitsky D, et al. The IRF family transcription factors in immunity and oncogene-sis[J]. Annu Rev Immunol, 2008, 26: 535-584. DOI: 10.1146/annurev.immunol.26.021607.090400.

8.Moorman HR, Reategui Y, Poschel DB, et al. IRF8: mechanism of action and health implications[J]. Cells, 2022, 11(17): 2630. DOI: 10.3390/cells11172630.

9.Ziegler CGK, Allon SJ, Nyquist SK, et al. SARS-CoV-2 receptor ACE2 is an interferon-stimulated gene in human airway epithelial cells and is detected in specific cell subsets across tissues[J]. Cell, 2020, 181(5): 1016-1035. e19. DOI: 10.1016/j.cell.2020.04.035.

10.Poschel DB, Kehinde-Ige M, Klement JD, et al. IRF8 regulates intrinsic ferroptosis through repressing p53 expression to maintain tumor cell sensitivity to cytotoxic T lymphocytes[J]. Cells, 2023, 12(2): 310. DOI: 10.3390/cells12020310.

11.Lei G, Zhuang L, Gan B. Targeting ferroptosis as a vulnerability in cancer[J]. Nat Rev Cancer, 2022, 22(7): 381-396. DOI: 10.1038/s41568-022-00459-0.

12.Wang Y, Zhao Z, Xiao Z. The emerging roles of ferroptosis in pathophysiology and treatment of acute lung injury[J]. J Inflamm Res, 2023, 16: 4073-4085. DOI: 10.2147/jir.S420676.

13.Bezerra FS, Lanzetti M, Nesi RT, et al. Oxidative stress and inflammation in acute and chronic lung in-juries[J]. Antioxidants (Basel), 2023, 12(3): 548. DOI: 10.3390/antiox 12030548.

14.Herridge MS, Azoulay É. Outcomes after critical illness[J]. N Engl J Med, 2023, 388(10): 913-924. DOI: 10.1056/NEJMra2104669.

15.Jefferies CA. Regulating IRFs in IFN driven disease[J]. Front Immunol, 2019, 10: 325. DOI: 10.3389/fimmu.2019.00325.

16.Liang KL, Laurenti E, Taghon T. Circulating IRF8-expressing CD123+ CD127+ lymphoid progenitors: key players in human hematopoiesis[J]. Trends Immunol, 2023, 44(9): 678-692. DOI: 10.1016/j.it.2023.07.004.

17.Karki R, Lee E, Place D, et al. IRF8 regulates transcription of naips for NLRC4 inflammasome activa-tion[J]. Cell, 2018, 173(4): 920-933. e13. DOI: 10.1016/j.cell.2018.02.055.

18.Johnson KD, Jung MM, Tran VL, et al. Interferon regulatory factor-8-dependent innate immune alarm senses GATA2 deficiency to alter hematopoietic differentiation and function[J]. Curr Opin Hematol, 2023, 30(4): 117-123. DOI: 10.1097/moh.0000000000000763.

19.Salem S, Salem D, Gros P. Role of IRF8 in immune cells functions, protection against infections, and susceptibility to inflammatory diseases[J]. Hum Genet, 2020, 139(6-7): 707-721. DOI: 10.1007/s00439-020-02154-2.

20.Jiang X, Stockwell BR, Conrad M. Ferroptosis: mechanisms, biology and role in disease[J]. Nat Rev Mol Cell Biol, 2021, 22(4): 266-282. DOI: 10.1038/s41580-020-00324-8.