{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T05:24:41Z","timestamp":1786944281312,"version":"build-2736575974"},"reference-count":33,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T00:00:00Z","timestamp":1786924800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Immunol."],"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>Tuberculosis (TB) remains the deadliest infectious disease in humans; however, a robust immune response can either protect against or control the infection. Household contacts of TB patients can remain uninfected for decades, while a quarter of the world's population that is latently infected can remain healthy for years. Characterization of the effectors of such an immune response would help in developing novel host-directed tools to better treat and\/or prevent TB. IL-6 is a crucial cytokine that plays a central role in orchestrating a protective TB immune response; however, a delicate balance between its beneficial and detrimental effects must be maintained to effectively control the infection. Here, we aimed to characterize the cellular effectors that regulate IL-6 expression in mycobacteria-infected cells.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      We used PI3K and AKT inhibitors, as well as FOXO3-specific siRNA, to modulate FOXO3 activity in BCG-infected macrophages and assessed the effect on IL-6 expression. Reporter gene assays were performed using four IL-6 promoter constructs (-600 bp, -900 bp, -1.5 kb, and -2 kb).\n                      <jats:italic>In silico<\/jats:italic>\n                      analysis was carried out using Genomatix software and the Eukaryotic Promoter Database to identify Forkhead binding motifs, followed by mutagenesis experiments to validate their function.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      The PI3K\/AKT\/FOXO3 axis regulates IL-6 expression in human macrophages: FOXO3 activation (via PI3K or AKT inhibition) induced IL-6 expression, while FOXO3 silencing reduced IL-6 production in BCG-infected macrophages. FOXO3 positively regulated IL-6 promoter activity across all cloned fragments, with the strongest effect at -1.5 kb; extension to -2 kb modulated this FOXO3-mediated induction.\n                      <jats:italic>In silico<\/jats:italic>\n                      analysis identified three FOXO3-specific binding sites (-786, -1331, and -1631). Mutagenesis identified the motif at -1331 as the major positive regulator of IL-6 expression, while the motif at -1631 mediated the negative regulation exerted by the distal promoter fragment.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Discussion<\/jats:title>\n                    <jats:p>We report for the first time that FOXO3 exerts both positive and negative regulation of IL-6 transcription, fine-tuning its expression in mycobacteria-infected macrophages. Together with our previous report on FOXO3-mediated suppression of IL-10, these results highlight the crucial role of FOXO3 in the TB immune response and support targeting the PI3K\/Akt\/FOXO3 axis as a host-directed approach to improve TB treatment and prevention.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fimmu.2026.1888327","type":"journal-article","created":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T04:36:17Z","timestamp":1786941377000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Forkhead box O3 transcription factor fine-tunes IL-6 expression in mycobacteria-infected macrophages"],"prefix":"10.3389","volume":"17","author":[{"given":"Manel","family":"Mejri","sequence":"first","affiliation":[{"name":"Institut Pasteur de Tunis, Laboratory of Transmission, Control and Immunobiology of Infections LTCII LR16IPT02","place":["Tunis, Tunisia"]},{"name":"Universit\u00e9 Tunis El Manar","place":["Tunis, Tunisia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yoldoz","family":"Bouzguenda","sequence":"additional","affiliation":[{"name":"Institut Pasteur de Tunis, Laboratory of Transmission, Control and Immunobiology of Infections LTCII LR16IPT02","place":["Tunis, Tunisia"]},{"name":"Universit\u00e9 Tunis El Manar","place":["Tunis, Tunisia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sonia","family":"Ben Hamouda","sequence":"additional","affiliation":[{"name":"Universit\u00e9 Tunis El Manar","place":["Tunis, Tunisia"]},{"name":"Institut Pasteur de Tunis, Laboratoire d\u2019Epid\u00e9miologie Mol\u00e9culaire et Pathologie Exp\u00e9rimentale LR16IPT04","place":["Tunis, Tunisia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Khadija","family":"Essafi-Benkhadir","sequence":"additional","affiliation":[{"name":"Universit\u00e9 Tunis El Manar","place":["Tunis, Tunisia"]},{"name":"Institut Pasteur de Tunis, Laboratoire d\u2019Epid\u00e9miologie Mol\u00e9culaire et Pathologie Exp\u00e9rimentale LR16IPT04","place":["Tunis, Tunisia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Makram","family":"Essafi","sequence":"additional","affiliation":[{"name":"Institut Pasteur de Tunis, Laboratory of Transmission, Control and Immunobiology of Infections LTCII LR16IPT02","place":["Tunis, Tunisia"]},{"name":"Universit\u00e9 Tunis El Manar","place":["Tunis, Tunisia"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,8,17]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","article-title":"Global tuberculosis report 2025","year":"2025","DOI":"10.15212\/zoonoses-2026-0002"},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.1016\/j.crmicr.2024.100295","article-title":"Current research in microbial sciences impacts of MDR\/XDR-TB on the global tuberculosis epidemic: Challenges and opportunities","volume":"7","author":"Chin","year":"2024","journal-title":"Curr Res Microb Sci"},{"key":"B3","doi-asserted-by":"publisher","first-page":"1","DOI":"10.21203\/rs.3.rs-8714621\/v1","article-title":"Genetic modification of the BCG vaccine to overcome its limited efficacy in adults: A specialized review","author":"Francis","year":"2026"},{"key":"B4","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1177\/23259582261449285","article-title":"Global, regional, and national burden of HIV and drug-susceptible tuberculosis co-infection among adolescents and young adults","volume":"25","author":"Wu","year":"2026"},{"key":"B5","doi-asserted-by":"publisher","DOI":"10.2147\/jir.s517034","article-title":"Host immune response to Mycobacterium tuberculosis infection: Implications for vaccine development","volume":"18","author":"Liu","year":"2025"},{"key":"B6","doi-asserted-by":"publisher","DOI":"10.1038\/s41590-026-02544-0","article-title":"Airway immune signatures of protection and disease progression in recent human tuberculosis household contacts","volume":"27","author":"Branchett","year":"2026"},{"key":"B7","doi-asserted-by":"publisher","DOI":"10.1016\/j.smim.2014.09.011","article-title":"Pro- and anti-inflammatory cytokines in TB: A two-edged sword in","volume":"26","author":"Etna","year":"2014","journal-title":"Semin Immunol"},{"key":"B8","doi-asserted-by":"publisher","first-page":"597","DOI":"10.21775\/cimb.041.597","article-title":"Stealth strategies of Mycobacterium tuberculosis for immune evasion","volume":"41","author":"Naeem","year":"2021"},{"key":"B9","doi-asserted-by":"publisher","DOI":"10.15537\/1658-3175.8781","article-title":"Contribution of interleukin-6 (IL-6) to body defense and healing in pulmonary tuberculosis","volume":"47","author":"Adi","year":"2026","journal-title":"Saudi Med J."},{"key":"B10","doi-asserted-by":"publisher","DOI":"10.1016\/j.meegid.2021.105166","article-title":"Cytokine storm in tuberculosis and IL-6 involvement","volume":"97","author":"Boni","year":"2022","journal-title":"Infection Genet Evol"},{"key":"B11","doi-asserted-by":"publisher","first-page":"1","DOI":"10.3389\/fimmu.2025.1494283","article-title":"Management of tuberculosis risk, screening and preventive therapy in patients with chronic autoimmune arthritis undergoing biotechnological and targeted immunosuppressive agents","volume":"16","author":"Picchianti-Diamanti","year":"2025"},{"key":"B12","doi-asserted-by":"publisher","DOI":"10.3390\/cells9122695","article-title":"The role of gp130 cytokines in tuberculosis","volume":"9","author":"Ritter","year":"2020"},{"key":"B13","doi-asserted-by":"publisher","first-page":"1","DOI":"10.3389\/fimmu.2022.750068","article-title":"Pleiotropic effect of IL-6 produced by B-lymphocytes during early phases of adaptive immune responses against TB infection","volume":"13","author":"Linge","year":"2022"},{"key":"B14","doi-asserted-by":"publisher","DOI":"10.3389\/ftubr.2024.1438406","article-title":"The role of the immune response in developing tuberculosis infection: from latent infection to active tuberculosis","volume":"2","author":"Kudryavtsev","year":"2019"},{"key":"B15","doi-asserted-by":"publisher","first-page":"1","DOI":"10.3389\/fimmu.2023.1255533","article-title":"Interleukin 6: at the interface of human health and disease","volume":"6","author":"Grebenciucova","year":"2023"},{"key":"B16","doi-asserted-by":"publisher","DOI":"10.1038\/mi.2011.7","article-title":"The role of IL-10 in immune regulation during M. tuberculosis infection","volume":"4","author":"Redford","year":"2011"},{"key":"B17","doi-asserted-by":"publisher","DOI":"10.1016\/j.tube.2017.11.008","article-title":"Mycobacterium tuberculosis infection induces IL-10 gene expression by disturbing histone deacetylase 6 and histonedeacetylase 11 equilibrium in macrophages","volume":"108","author":"Wang","year":"2018","journal-title":"Tuberculosis"},{"key":"B18","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2567.2010.03402.x","article-title":"Interleukin- 10 -induced gene expression and suppressive function are selectively modulated by the PI 3 K-Akt-GSK 3 pathway","volume":"132","author":"Antoniv","year":"2011"},{"key":"B19","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1371\/journal.pone.0093810","article-title":"Involvement of the Akt\/NF-kB pathways in the HTNV-mediated increase of IL-6, CCL5, ICAM-1, and VCAM-1 in HUVECs","volume":"9","author":"Yu","year":"2014"},{"key":"B20","doi-asserted-by":"publisher","DOI":"10.1016\/j.yexcr.2019.04.019","article-title":"CSTP1 inhibits IL-6 expression through targeting Akt\/FoxO3a signaling pathway in bladder cancer cells","volume":"380","author":"Zhuo","year":"2019","journal-title":"Exp Cell Res"},{"key":"B21","doi-asserted-by":"publisher","DOI":"10.3389\/fimmu.2019.02922","article-title":"FOXO3 transcription factor regulates IL-10 expression in mycobacteria-infected macrophages, tuning their polarization and the subsequent adaptive immune response","volume":"10","author":"Bouzeyen","year":"2019","journal-title":"Front Immunol"},{"key":"B22","doi-asserted-by":"publisher","DOI":"10.3389\/fimmu.2021.645962","article-title":"Co-administration of anticancer candidate MK-2206 enhances the efficacy of BCG vaccine against Mycobacterium tuberculosis in mice and Guinea pigs","volume":"12","author":"Bouzeyen","year":"2021","journal-title":"Front Immunol"},{"key":"B23","doi-asserted-by":"publisher","DOI":"10.1111\/cmi.12298","article-title":"Forkhead box O3 (FOXO3) transcription factor mediates apoptosis in BCG-infected macrophages","volume":"16","author":"Haoues","year":"2014","journal-title":"Cell Microbiol"},{"key":"B24","doi-asserted-by":"publisher","DOI":"10.1091\/mbc.E07-06-0570","article-title":"Tristetraprolin inhibits Ras-dependent tumor vascularization by inducing vascular endothelial growth factor mRNA degradation","volume":"18","author":"Essafi-Benkhadir","year":"2007","journal-title":"Mol Biol Cell."},{"key":"B25","doi-asserted-by":"publisher","DOI":"10.1016\/j.imbio.2014.03.016","article-title":"Regulation of the interleukin-6 gene expression during monocytic differentiation of HL-60 cells by chromatin remodeling and methylation","volume":"219","author":"Poplutz","year":"2014","journal-title":"Immunobiology"},{"key":"B26","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1038\/ncomms12748","article-title":"Salmonella typhimurium","volume":"7","author":"Joseph","year":"2016","journal-title":"Nat Commun"},{"key":"B27","doi-asserted-by":"publisher","DOI":"10.1128\/MCB.01657-08","article-title":"Hyperactivated NF-kB and AP-1 transcription factors promote highly accessible chromatin and constitutive transcription across the interleukin-6 gene promoter in metastatic breast cancer cells","volume":"29","author":"Ndlovu","year":"2009"},{"key":"B28","doi-asserted-by":"publisher","DOI":"10.1016\/j.immuni.2004.06.016","article-title":"Regulation of NF-kB, Th activation, and autoinflammation by the forkhead transcription factor Foxo3a","volume":"21","author":"Lin","year":"2004"},{"key":"B29","doi-asserted-by":"publisher","DOI":"10.1038\/nrm3507","article-title":"FOXOs: signalling integrators for","author":"Eijkelenboom","year":"2013","journal-title":"Nat Rev Mol Cell Biol"},{"key":"B30","doi-asserted-by":"publisher","DOI":"10.3892\/mmr.2016.5867","article-title":"Post-translational modifications of FOXO family proteins (review)","author":"Wang","year":"2016"},{"key":"B31","doi-asserted-by":"publisher","DOI":"10.1016\/j.celrep.2013.11.031","article-title":"Article FOXO3 selectively amplifies enhancer activity to establish target gene regulation","volume":"5","author":"Eijkelenboom","year":"2013","journal-title":"Cell Rep"},{"key":"B32","doi-asserted-by":"publisher","DOI":"10.1038\/ni.1729","article-title":"Transcription factor Foxo3 controls the magnitude of T cell immune responses by modulating the function of dendritic cells","volume":"10","author":"Dejean","year":"2009"},{"key":"B33","doi-asserted-by":"publisher","DOI":"10.3389\/fimmu.2022.987018","article-title":"Immune regulation and emerging roles of noncoding RNAs in Mycobacterium tuberculosis infection","volume":"13","author":"Liang","year":"2022"}],"container-title":["Frontiers in Immunology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fimmu.2026.1888327\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T04:36:18Z","timestamp":1786941378000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fimmu.2026.1888327\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,17]]},"references-count":33,"alternative-id":["10.3389\/fimmu.2026.1888327"],"URL":"https:\/\/doi.org\/10.3389\/fimmu.2026.1888327","relation":{},"ISSN":["1664-3224"],"issn-type":[{"value":"1664-3224","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,17]]},"article-number":"1888327"}}