Commentary | Volume 3 - Issue 1 | Article DOI :
Download PDF
Remo C. Russo1 and Bernhard Ryffel2,3*
1Laboratory of Pulmonary Immunology and Mechanics, Federal University of Minas Gerais, Brazil
2University of Orleans and CNRS UMR7355, Immunologie Neurogénétique Expérimentales et Moléculaires INEM, France
3ArtImmune SAS, 13 Avenue Buffon, Orleans, France.
Corresponding Author:
Bernhard Ryffel, University of Orleans and CNRS UMR7355, Immunologie Neurogénétique Expérimentales et Moléculaires INEM, UMR7355, Orleans, France.
Keywords
Pollution, O3, DAMPs, Inflammasome, Alarmin, IL-33.
Abstract
Chronic exposure to ambient Ozone (O3) air pollution induces respiratory inflammation and hyperreactivity, emphysema and interstitial lung fibrosis. O3-induced oxidative stress causes epithelial barrier injury and cell death activating Toll-like receptors, DNA sensing pathways and inflammasomes with production of a range of inflammatory chemokines with a mixed phenotype of COPD and asthma. O3 exposure is often associated with other pollutants causing exacerbation leading to severe respiratory disease. Here, we review mechanisms and therapeutic targets to control O3-induced COPD-like disease.
Citation
Ryffel B, Russo RC (2025) Commentary Pathways and Thera peutic Targets of Ozone induced Lung Disease. Ann Environ Sci Ecol 3: 5.
PATHWAYS
Ozone (O3 ) is a highly reactive air pollutant, inducing oxidative damage that swiftly results in cell injury and death. The resultant oxidative stress on the host likely constitutes a primary mechanism causing an inflammatory response. Prolonged exposure to O3-polluted air is associated with increased morbidity and mortality, along with heightened responses to microbial or allergen challenges [1-3]. Hyaluronic acid (HA), a degradation product of matrix components, and HSP70, generated by O3-induced tissue damage, may potentially activate TLR4 [4-6]. Furthermore, the TLR adaptor proteins MyD88 and TIRAP are indispensable for the inflammatory response [5], as they activate NF κB and regulate cytokine gene expression.
IL-1β is a potent inflammatory mediator induced by bacterial infection and tissue injury [7] involving the activation of the inflammasome complex in the response to O3 [8].
THERAPEUTIC TARGETS FOR PHARMACOLOGICAL INTERVENTIONS:
The existing experimental data offer promising drug targets for mitigating O3-induced chronic inflammatory lung disease. Nonetheless, the efficacy of therapeutic interventions tested in mouse models necessitates validation through clinical studies. Below, we outline the potential efficacy of agonists or antagonists that merit consideration for inclusion in clinical trials (Figure 1):
Figure 1: Lung-resident cell signatures from healthy humans and mice revealed that they are able to prompt response to tissue injury by DAMP and Alarmin expression. Visualization of dimension-reduced single-cell transcriptomic data (scRNAseq) by Uniform Manifold Approximation and Projection (UMAP) reveals different annotated cell types in the human lung (A) and in the mouse lung (C). UMAP embedded visualization of “DAMP and Alarmin signaling” and “Inflammasome and Interleukin-1 signaling” related gene expression in human lung cells (B) and in mouse lung cells (D). Cell gene signatures from UMAP embedded visualization of related gene expression in healthy mouse lung cells (E). Human lung single-cell data was taken from the integrated Human Lung Cell Atlas (HLCA) core, including data from healthy lung tissue from 107 individuals. The data was downloaded via cellxgene (https://cellxgene.cziscience.com/collections/6f6d381a-7701-4781-935c db10d30de293). Mouse lung single-cell data is downloaded under GEO accession: GSE185006, containing mice exposed to filtered air (FA) or cigarette smoking for 2 and 4 months to establish a COPD model. Only 6 lungs from mice exposed to FA were included in the study to represent healthy lungs [26, 27]. Lianyong, please explain shortly how you analyzed these data, once that, the method will be mentioned here.
• T N F neutralization presents a potential option, but reduces host innate immunity.
• IL-1β neutralizing antibodies or IL-1 receptor antagonist (Anakinra).
• Neutralizing antibodies targeting IL-23 and IL-17A are currently available.
• Dampening of NRP3 inflammasome activation using inhibitors such as MCC950 [9-11]
• Blockade of nucleic acid sensor activation, notably cGAS/STING, using antagonists [11].
• Aryl hydrocarbon receptor activation by microbial tryptophan metabolites and more [12]
• Blockade of cholinergic pathway activated suggest a beneficial effect of the cholinergic pathways [13].
• Muscarinergic inhibitors such as Tiotropium and are efficacious in COPD patients [14-18].
• ROS inhibitors such as N-acetyl cysteine attenuate O3 inflammation reviewed [19].
• Microbial metabolites, such as butyrate activating /HCAR2, attenuate inflammatory diseases [20, 21].
• Histone modulators of histone deacetylases (HDAC) is another approach using HDAC inhibitors [22].
• DNase treatment degrades inflammatory cell-free DNA upon cell death degrading DNA [23, 24].
• Inhibitors suppressing myofibroblast transdifferentiation, such as by N23Ps (N-(2-methoxyphenyl)-3-(phenyl)acrylamides) and derivatives are novel compounds suppressing myofibroblast transdifferentiation, collagen deposition, and fibrosis. N23Ps target SMURF2, a SMAD-specific E3 ubiquitin protein ligase2 [25].
NOVEL COMPOUNDS SUPPRESSING MYOFIBROBLAST TRANSDIFFERENTIATION
Lung fibrosis involves the excessive deposition of ECM components, mainly collagen, leading to scarring and impaired lung function. The differentiation of fibroblasts into myofibroblasts is a crucial event in this process. This differentiation is driven by profibrotic signals such as TGF-β and results in increased collagen synthesis and tissue stiffening, contributing to the pathological remodeling observed in fibrotic lung diseases. Understanding this process is crucial for developing therapeutic strategies to inhibit or reverse fibrosis. N23Ps (N-(2-methoxyphenyl) 3-(phenyl)acrylamides) are a novel class of highly potent class of compounds suppressing myofibroblast transdifferentiation, collagen deposition, cellular contractility, and altered cell shapes with a unique mode of action. Mechanistically, transcriptomics identified the SMURF2, a SMAD-specific E3 ubiquitin protein ligase2, as a potential therapeutic target network. Antifibrotic activity of N23Ps was verified by proteomics in a human ex vivo tissue fibrosis disease model, suppressing profibrotic markers SERPINE1 and CXCL8. N23Ps are highly potent developmental compounds inhibiting organ fibrosis in patients [25].
While the list of proposed therapeutic targets is not exhaustive, ongoing research to refine inhibitors and gain new mechanistic insights holds promise for developing more efficacious antagonists. Advancements in understanding the complex pathways underlying chronic inflammatory lung diseases may uncover additional targets for intervention. However, it is essential to recognize that while pharmacological approaches offer potential benefits, addressing the root cause of these diseases is paramount. In this regard, reducing airborne pollution with exceptionally high levels of O3 and smog stands out as the most efficacious measure to prevent the onset and progression of chronic respiratory ailments. Implementing comprehensive strategies to curb pollution, including regulatory measures, technological innovations, and public awareness campaigns, could significantly alleviate the burden of these debilitating conditions on global health [25-28] (Figure 2).
Figure 2: Ozone (O3)-exposure induced acute and chronic alterations in mice lungs: Role of oxeiptosis, alarmins, DAMPs, and inflammasome pathways. Ozone-induced oxeiptosis is a caspase-independent, ROS-sensitive cell death pathway distinct from traditional apoptosis (A). This pathway involves the key molecules NRF2, KEAP1, PGAM5, and AIMF1. Oxeiptosis occurs by the disruption of the protective antioxidant complex KEAP1/PGAM5/NRF2, releasing NRF2 and the phosphatase PGAM5, which activates AIFM1. PGAM5, in response to oxidative stress induced by O3, dephosphorylates AIFM1, a pro-apoptotic factor that is a terminal effector protein. Dephosphorylated AIFM1 is translocated from mitochondria to the nucleus, which induces chromatin condensation, DNA fragmentation, and cell death. Experimental design of O3-induced lung injury and RNAseq of lung tissue (B), characterized as acute (single O3-exposure, GSE161538) and chronic (multiple O3-exposure, GSE156799) models. RNAseq analysis showing RNA differential expression comparing O3-exposure normalized by exposure to filtered air, from GSE161538 (Single ozone 2ppm 3h, n= 7 filtered air-exposed and 4 O3-exposed mice) and GSE156799 (Ozone 0.8 ppm 4h/day, during 3 weeks, n= 8 filtered air and 8 O3-exposed mice) (C-F). Heatmap of RNAseq expression (C), RNAseq differential expression of acute model Day 1 (D) and Day 4 (E) after a single O3-exposure (GSE161538), and chronic model after 3 weeks (F) of multiple O3-exposure (GSE156799). RNAseq datasets found in the Gene Expression Omnibus (GEO) database (https://www.ncbi.nlm.nih.gov/geo/) were analyzed by Phantasus (https://genome.ifmo.ru/phantasus) and presented as Log2 Fold Change (Log2FC) [28]. Differences were considered significant at the Adjusted P-value <0,05. Red represents significative up-regulated and blue significative down-regulated genes (D-F). Venn diagram illustrating common up-regulated genes induced by O3-exposure of acute (Day 1 and Day 4) and chronic (3 weeks) models (G). The proposed mechanism of acute and chronic lung injury induced by O3 exposure shows that Il-33, Areg, and Myd88 may represent possible targets to control lung inflammation (H). Illustration A and H were constructed using Biorender.
CONCLUSION
O3 exposure initiates cellular damage, initially causing oxeiptosis of the resident cell lining barrier, including leukocytes and non leukocytes. Acute O3 exposure leads to ROS activating the NLRP3 inflammasome and release of mature IL-1α/β, a potent inflammatory mediator, activating neutrophils and macrophages causing additional tissue damage. Furthermore, ROS activate TLR, inflammasomes and DNA sensors triggering inflammatory mediators (IL-1β, TNF, IL-6, IL 10, IL-17), and others. In silico analysis revealed that O3 exposure is correlated with the upregulation of Il-33, Areg and Myd88 in the lungs, as well as the antioxidant Nfe2l2 (NFR2) and apoptotic protein Aimf1 genes, suggesting that they are essential in O3-induced acute and chronic airway inflammation in mice, may be sustained by oxeiptosis and type 2 immune response. Prolonged exposure to O3 and other particulate pollutants exacerbates inflammation and may contribute to developing conditions such as emphysema, chronic inflammation, and fibrosis. Further exploring these inflammatory pathways is warranted to better understand their role in O3-induced lung injury and develop targeted therapeutic interventions
ACKNOWLEDGMENTS
Authors are supported by Centre National de la Recherche Scientifique (CNRS), University of Orleans, Fondation pour la Recherche Médicale’ (FRM EQU202003010405), European funding in Region Centre-Val de Loire (FEDER TARGET-Ex EX016008 and ExposomeInflam), ‘Region Centre-Val de Loire’ (RespirO3 , 2014-00091905), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq – Brazil, 313839/2023 9), Fundação de Amparo a Pesquisa de Minas Gerais (FAPEMIG – Brazil, APQ-02571-21 and RED-00031-21), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Programa CAPES-PrInt/UFMG edital 05/2022.
REFERENCES
1. Hollingsworth JW, Free ME, Li Z, Andrews LN, Nakano H, Cook DN. Ozone activates pulmonary dendritic cells and promotes allergic sensitization through a Toll-like receptor 4-dependent mechanism. J Allergy Clin Immunol. 2010; 125: 1167-1170.
2. Last JA, Ward R, Temple L, Kenyon NJ. Ovalbumin-induced airway inflammation and fibrosis in mice also exposed to ozone. Inhal Toxicol. 2004; 16: 33-43.
3. Liang L, Li F, Bao A, Zhang M, Chung KF, Zhou X. Activation of p38 mitogen-activated protein kinase in ovalbumin and ozone-induced mouse model of asthma. Respirology. 2013; 18: 20-29.
4. Li Z, Potts EN, Piantadosi CA, Foster WM, Hollingsworth JW. Hyaluronan fragments contribute to the ozone-primed immune response to lipopolysaccharide. J Immunol. 2010; 185: 6891-6898.
5. Li Z, Potts-Kant EN, Garantziotis S, Foster WM, Hollingsworth JW. Hyaluronan signaling during ozone-induced lung injury requires TLR4, MyD88, and TIRAP. PLoS One. 2011; 6: e27137.
6. Bauer AK, Travis EL, Malhotra SS, Rondini EA, Walker C, Cho HY, et al. Identification of novel susceptibility genes in ozone-induced inflammation in mice. Eur Respir J. 2010; 36: 428-437.
7. Dinarello CA. Interleukin-1beta and the autoinflammatory diseases. N Engl J Med. 2009; 360: 2467-2470.
8. Michaudel C, Couturier-Maillard A, Chenuet P, Maillet I, Mura C, Couillin I, et al. Inflammasome, IL-1 and inflammation in ozone-induced lung injury. Am J Clin Exp Immunol. 2016; 5: 33-40.
9. Coll RC, Robertson AA, Chae JJ, Higgins SC, Muñoz-Planillo R, Inserra MC, et al. A small-molecule inhibitor of the NLRP3 inflammasome for the treatment of inflammatory diseases. Nat Med. 2015; 21: 248-255.
10. Hooftman A, Angiari S, Hester S, Corcoran SE, Runtsch MC, Ling C, et al. The Immunomodulatory Metabolite Itaconate Modifies NLRP3 and Inhibits Inflammasome Activation. Cell Metab. 2020; 32: 468-478.e7.
11. Haag SM, Gulen MF, Reymond L, Gibelin A, Abrami L, Decout A, et al. Targeting STING with covalent small-molecule inhibitors. Nature. 2018; 559: 269-273.
12. Hezaveh K, Shinde RS, Klötgen A, Halaby MJ, Lamorte S, Ciudad MT, et al. Tryptophan-derived microbial metabolites activate the aryl hydrocarbon receptor in tumor-associated macrophages to suppress anti-tumor immunity. Immunity. 2022; 55: 324-340.e8.
13. Yamada M, Ichinose M. The cholinergic anti-inflammatory pathway: an innovative treatment strategy for respiratory diseases and their comorbidities. Curr Opin Pharmacol. 2018; 40: 18-25.
14. Bateman ED, Rennard S, Barnes PJ, Dicpinigaitis PV, Gosens R, Gross NJ, et al. Alternative mechanisms for tiotropium. Pulm Pharmacol Ther. 2009; 22: 533-542.
15. Kerstjens HA, Moroni-Zentgraf P, Tashkin DP, Dahl R, Paggiaro P, Vandewalker M, et al. Tiotropium improves lung function, exacerbation rate, and asthma control, independent of baseline characteristics including age, degree of airway obstruction, and allergic status. Respir Med. 2016; 117: 198-206.
16. Kistemaker LEM, Elzinga CRS, Tautermann CS, Pieper MP, Seeliger D, Alikhil S, et al. Second M3 muscarinic receptor binding site contributes to bronchoprotection by tiotropium. Br J Pharmacol. 2019;176: 2864-2876.
17. Tashkin DP, Bateman ED, Jones P, Zubek VB, Metzdorf N, Liu D, et al. Consistent improvement in health-related quality of life with tiotropium in patients with chronic obstructive pulmonary disease: Novel and conventional responder analyses. Respir Med. 2016; 120: 91-100.
18. Wollin L, Pieper MP. Tiotropium bromide exerts anti-inflammatory activity in a cigarette smoke mouse model of COPD. Pulm Pharmacol Ther. 2010; 23: 345-354.
19. Wiegman CH, Li F, Ryffel B, Togbe D, Chung KF. Oxidative Stress in Ozone-Induced Chronic Lung Inflammation and Emphysema: A Facet of Chronic Obstructive Pulmonary Disease. Front Immunol. 2020; 11: 1957.
20. Corrêa RO, Castro PR, Moser R, Ferreira CM, Quesniaux VFJ, Vinolo MAR, et al. Butyrate: Connecting the gut-lung axis to the management of pulmonary disorders. Front Nutr. 2022; 9: 1011732.
21. Lewis G, Wang B, Shafiei Jahani P, Hurrell BP, Banie H, Aleman Muench GR, et al. Dietary Fiber-Induced Microbial Short Chain Fatty Acids Suppress ILC2-Dependent Airway Inflammation. Front Immunol. 2019; 10: 2051.
22. Fellows R, Varga-Weisz P. Chromatin dynamics and histone modifications in intestinal microbiota-host crosstalk. Mol Metab. 2020; 38: 100925.
23. Liu Y, Ma YH, Yang JW, Man JW, Wang HB, Li Y, et al. Rethinking neutrophil extracellular traps. Int Immunopharmacol. 2023; 124: 110834.
24. Yadav R, Momin A, Godugu C. DNase based therapeutic approaches for the treatment of NETosis related inflammatory diseases. Int Immunopharmacol. 2023; 124: 110846.
25. Gerckens M, Schorpp K, Pelizza F, Wögrath M, Reichau K, Ma H, et al. Phenotypic drug screening in a human fibrosis model identified a novel class of antifibrotic therapeutics. Sci Adv. 2021; 7: eabb3673.
26. Sikkema L, Ramírez-Suástegui C, Strobl DC, Gillett TE, Zappia L, Madissoon E, et al. An integrated cell atlas of the lung in health and disease. Nat Med. 2023; 29: 1563-1577.
27. Günes Günsel G, Conlon TM, Jeridi A, Kim R, Ertüz Z, Lang NJ, et al. The arginine methyltransferase PRMT7 promotes extravasation of monocytes resulting in tissue injury in COPD. Nat Commun. 2022; 13: 1303.
28. Russo RC, Quesniaux VFJ, Ryffel B. Homeostatic chemokines as putative therapeutic targets in idiopathic pulmonary fibrosis. Trends Immunol. 2023; 44: 1014-1030.
