Journal of immunology最新文献

{"title":"ATM-dependent Phosphorylation of Nemo SQ Motifs Is Dispensable for Nemo-mediated Gene Expression Changes in Response to DNA Double-Strand Breaks.","authors":"Rebecca A Glynn, Katharina E Hayer, Craig H Bassing","doi":"10.4049/jimmunol.2300139","DOIUrl":"10.4049/jimmunol.2300139","url":null,"abstract":"<p><p>In response to DNA double-strand breaks (DSBs), the ATM kinase activates NF-κB factors to stimulate gene expression changes that promote survival and allow time for cells to repair damage. In cell lines, ATM can activate NF-κB transcription factors via two independent, convergent mechanisms. One is ATM-mediated phosphorylation of nuclear NF-κB essential modulator (Nemo) protein, which leads to monoubiquitylation and export of Nemo to the cytoplasm where it engages the IκB kinase (IKK) complex to activate NF-κB. Another is DSB-triggered migration of ATM into the cytoplasm, where it promotes monoubiquitylation of Nemo and the resulting IKK-mediated activation of NF-κB. ATM has many other functions in the DSB response beyond activation of NF-κB, and Nemo activates NF-κB downstream of diverse stimuli, including developmental or proinflammatory stimuli such as LPSs. To elucidate the in vivo role of DSB-induced, ATM-dependent changes in expression of NF-κB-responsive genes, we generated mice expressing phosphomutant Nemo protein lacking consensus SQ sites for phosphorylation by ATM or related kinases. We demonstrate that these mice are viable/healthy and fertile and exhibit overall normal B and T lymphocyte development. Moreover, treatment of their B lineage cells with LPS induces normal NF-κB-regulated gene expression changes. Furthermore, in marked contrast to results from a pre-B cell line, primary B lineage cells expressing phosphomutant Nemo treated with the genotoxic drug etoposide induce normal ATM- and Nemo-dependent changes in expression of NF-κB-regulated genes. Our data demonstrate that ATM-dependent phosphorylation of Nemo SQ motifs in vivo is dispensable for DSB-signaled changes in expression of NF-κB-regulated genes.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":" ","pages":"628-640"},"PeriodicalIF":3.6,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11348802/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141616659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Evolving Portrait of γδ TCR Recognition Determinants.","authors":"Chhon Ling Sok, Jamie Rossjohn, Benjamin S Gully","doi":"10.4049/jimmunol.2400114","DOIUrl":"10.4049/jimmunol.2400114","url":null,"abstract":"<p><p>In αβ T cells, immunosurveillance is enabled by the αβ TCR, which corecognizes peptide, lipid, or small-molecule Ags presented by MHC- and MHC class I-like Ag-presenting molecules, respectively. Although αβ TCRs vary in their Ag recognition modes, in general they corecognize the presented Ag and the Ag-presenting molecule and do so in an invariable \"end-to-end\" manner. Quite distinctly, γδ T cells, by way of their γδ TCR, can recognize ligands that extend beyond the confines of MHC- and MHC class I-like restrictions. From structural studies, it is now becoming apparent that γδ TCR recognition modes can break the corecognition paradigm and deviate markedly from the end-to-end docking mechanisms of αβ TCR counterparts. This brief review highlights the emerging portrait of how γδ TCRs can recognize diverse epitopes of their Ags in a manner reminiscent to how Abs recognize Ags.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":"213 5","pages":"543-552"},"PeriodicalIF":3.6,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11335310/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142004394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sepsis Impairs IFN-γ Production in CD8 T Cells through Changes in Local Chromatin Landscape.","authors":"J Alejandro Cisneros-Segura, Noé Rodríguez-Rodríguez, Adrián Albarrán-Godínez, H Benjamín García-González, Carlos A Rodríguez-Osorio, Sergio Iván Valdés-Ferrer, Gustavo Tapia-Urzúa, Félix Recillas-Targa, Iris K Madera-Salcedo, Florencia Rosetti, José C Crispín","doi":"10.4049/jimmunol.2300772","DOIUrl":"10.4049/jimmunol.2300772","url":null,"abstract":"<p><p>Sepsis is a complex condition of inflammatory and immune dysregulation, triggered by severe infection. In survivors, chronic inflammation and immune dysregulation linger, facilitating the emergence of infections. CD8 dysfunction contributes to immunosuppression in sepsis survivors. We devised an animal model that enabled us to identify and analyze CD8-intrinsic defects induced by sepsis. We adoptively transferred CD45.1 CD8 OT-I T cells into CD45.2 congenic mice and subjected them to cecal ligature and puncture, to induce abdominal sepsis. One month later, we isolated the transferred CD8 cells. Surface marker expression confirmed they had not been activated through the TCR. CD8 OT-I T cells isolated from septic (or sham-operated) mice were transferred to second recipients, which were challenged with OVA-expressing Listeria monocytogenes. We compared effector capacities between OT-I cells exposed to sepsis and control cells. Naive mice that received OT-I cells exposed to sepsis had higher bacterial burden and a shorter survival when challenged with OVA-expressing L. monocytogenes. OT-I cells isolated from septic mice produced less IFN-γ but had conserved activation, expansion potential, and cytotoxic function. We observed lower transcript levels of IFN-γ and of the long noncoding RNA Ifng-as1, a local regulator of the epigenetic landscape, in cells exposed to sepsis. Accordingly, local abundance of a histone modification characteristic of active promoter regions was reduced in sepsis-exposed CD8 T cells. Our results identify a mechanism through which inflammation in the context of sepsis affects CD8 T cell function intrinsically.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":" ","pages":"619-627"},"PeriodicalIF":3.6,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141734286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aryl Hydrocarbon Receptor Activation in Pulmonary Alveolar Epithelial Cells Limits Inflammation and Preserves Lung Epithelial Cell Integrity.","authors":"Elizabeth Zimmerman, Anne Sturrock, Christopher A Reilly, Katherine L Burrell-Gerbers, Kristi Warren, Mustafa Mir-Kasimov, Mingyang A Zhang, Megan S Pierce, My N Helms, Robert Paine","doi":"10.4049/jimmunol.2300325","DOIUrl":"10.4049/jimmunol.2300325","url":null,"abstract":"<p><p>The aryl hydrocarbon receptor (AHR) is a receptor/transcription factor widely expressed in the lung. The physiological roles of AHR expressed in the alveolar epithelium remain unclear. In this study, we tested the hypothesis that alveolar epithelial AHR activity plays an important role in modulating inflammatory responses and maintaining alveolar integrity during lung injury and repair. AHR is expressed in alveolar epithelial cells (AECs) and is active. AHR activation with the endogenous AHR ligand, FICZ (5,11-dihydroindolo[3,2-b] carbazole-6-carboxaldehyde), significantly suppressed inflammatory cytokine expression in response to inflammatory stimuli in primary murine AECs and in the MLE-15 epithelial cell line. In an LPS model of acute lung injury in mice, coadministration of FICZ with LPS suppressed protein leak, reduced neutrophil accumulation in BAL fluid, and suppressed inflammatory cytokine expression in lung tissue and BAL fluid. Relevant to healing following inflammatory injury, AHR activation suppressed TGF-β-induced expression of genes associated with epithelial-mesenchymal transition. Knockdown of AHR in primary AECs with shRNA or in CRISPR-Cas-9-induced MLE-15 cells resulted in upregulation of α-smooth muscle actin (αSma), Col1a1, and Fn1 and reduced expression of epithelial genes Col4a1 and Sdc1. MLE-15 clones lacking AHR demonstrated accelerated wound closure in a scratch model. AHR activation with FICZ enhanced barrier function (transepithelial electrical resistance) in primary murine AECs and limited decline of transepithelial electrical resistance following inflammatory injury. AHR activation in AECs preserves alveolar integrity by modulating inflammatory cytokine expression while enhancing barrier function and limiting stress-induced expression of mesenchymal genes.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":" ","pages":"600-611"},"PeriodicalIF":3.6,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11335325/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141734285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Salmonid Double-stranded RNA-Dependent Protein Kinase Activates Apoptosis and Inhibits Protein Synthesis.","authors":"Lise Chaumont, Mathilde Peruzzi, François Huetz, Claudine Raffy, Jérôme Le Hir, Jules Minke, Pierre Boudinot, Bertrand Collet","doi":"10.4049/jimmunol.2400076","DOIUrl":"10.4049/jimmunol.2400076","url":null,"abstract":"<p><p>dsRNA-dependent protein kinase R (PKR) is a key factor of innate immunity. It is involved in translation inhibition, apoptosis, and enhancement of the proinflammatory and IFN responses. However, how these antiviral functions are conserved during evolution remains largely unknown. Overexpression and knockout studies in a Chinook salmon (Oncorhynchus tshawytscha) cell line were conducted to assess the role of salmonid PKR in the antiviral response. Three distinct mRNA isoforms from a unique pkr gene, named pkr-fl (full length), pkr-ml (medium length) and pkr-sl (short length), were cloned and a pkr-/- clonal fish cell line was developed using CRISPR/Cas9 genome editing. PKR-FL includes an N-terminal dsRNA-binding domain and a C-terminal kinase domain, whereas PKR-ML and PKR-SL display a truncated or absent kinase domain, respectively. PKR-FL is induced during IFNA2 stimulation but not during viral hemorrhagic septicemia virus (VHSV) infection. Overexpression experiments showed that only PKR-FL possesses antiviral functions, including activation of apoptosis and inhibition of de novo protein synthesis. Knockout experiments confirmed that PKR is involved in apoptosis activation during the late stage of VHSV infection. Endogenous PKR also plays a critical role in translation inhibition upon poly(I:C) transfection after IFNA2 treatment. It is, however, not involved in translational arrest during VHSV infection. Extra- and intracellular titrations showed that endogenous PKR does not directly inhibit viral replication but apparently favors virion release into the supernatant, likely by triggering late apoptosis. Altogether, our data confirm that salmonid PKR has conserved molecular functions that VHSV appears to bypass with subversion strategies.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":" ","pages":"700-717"},"PeriodicalIF":3.6,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141759147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crystal Structures of DNA-bound Fish IRF10 and IRF11 Reveal the Determinants of IFN Regulation.","authors":"Zhao-Xi Wang, Bin Liu, Haizhou Xie, Xin Liu, Xiangliang Li, Fuqiang Shi, Songying Ouyang, Yong-An Zhang","doi":"10.4049/jimmunol.2300414","DOIUrl":"10.4049/jimmunol.2300414","url":null,"abstract":"<p><p>IFN regulatory factors (IRFs) are transcription factors that mediate homeostatic mechanisms of host defense against pathogens. In addition to IRF1-9, which are conserved across vertebrates, teleost fishes have two other IRFs, IRF10 and IRF11. In zebrafish (Danio rerio), IRF10 represses the expression of IFNφ1 and IFNφ3, whereas IRF11 exerts the opposite effect. In this study, we found IRF10 could significantly inhibit the expression of IFNφ1 and IFNφ3 induced by IFN11 to synergistically regulate type I IFN expression. To clarify the synergistically regulatory mechanism of IRF10 and IRF11 in type I IFN expression, we determined and analyzed the crystal structures of the DNA-binding domains (DBDs) of zebrafish IRF10 and IRF11 bound to DNA, as well as IRF11 DBD in apo form. The interactions of IRF10-DBD and IRF11-DBD with DNA backbone were elaborated in detail. Further analysis showed that IRF10 and IRF11 have the same binding patterns and comparable affinities with the IFN-sensitive response elements of IFNφ1 and IFNφ3 promoters. Therefore, IRF10 could function as a controlling factor for IRF11 by competitive binding of the IFN-sensitive response elements to coregulate the host IFN response. Accordingly, similar to IRF1 and IRF2 in mammals, IRF10 and IRF11 act as another pair of negative and positive regulators to balance the antiviral responses in fish.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":" ","pages":"743-752"},"PeriodicalIF":3.6,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141759146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Endometriotic Tissue-derived Exosomes Downregulate NKG2D-mediated Cytotoxicity and Promote Apoptosis: Mechanisms for Survival of Ectopic Endometrial Tissue in Endometriosis.","authors":"Emma Björk, Pernilla Israelsson, Ivan Nagaev, Olga Nagaeva, Eva Lundin, Ulrika Ottander, Lucia Mincheva-Nilsson","doi":"10.4049/jimmunol.2300781","DOIUrl":"10.4049/jimmunol.2300781","url":null,"abstract":"<p><p>Endometriosis, affecting 10% of women, is defined as implantation, survival, and growth of endometrium-like/endometriotic tissue outside the uterine cavity, causing inflammation, infertility, pain, and susceptibility to ovarian cancer. Despite extensive studies, its etiology and pathogenesis are poorly understood and largely unknown. The prevailing view is that the immune system of endometriosis patients fails to clear ectopically disseminated endometrium from retrograde menstruation. Exosomes are small extracellular vesicles that exhibit immunomodulatory properties. We studied the role of endometriotic tissue-secreted exosomes in the pathophysiology of endometriosis. Two exosome-mediated mechanisms known to impair the immune response were investigated: 1) downregulation of NKG2D-mediated cytotoxicity and 2) FasL- and TRAIL-induced apoptosis of activated immune cells. We showed that secreted endometriotic exosomes isolated from supernatants of short-term explant cultures carry the NKG2D ligands MICA/B and ULBP1-3 and the proapoptotic molecules FasL and TRAIL on their surface, i.e., signature molecules of exosome-mediated immune suppression. Acting as decoys, these exosomes downregulate the NKG2D receptor, impair NKG2D-mediated cytotoxicity, and induce apoptosis of activated PBMCs and Jurkat cells through the FasL- and TRAIL pathway. The secreted endometriotic exosomes create an immunosuppressive gradient at the ectopic site, forming a \"protective shield\" around the endometriotic lesions. This gradient guards the endometriotic lesions against clearance by a cytotoxic attack and creates immunologic privilege by induction of apoptosis in activated immune cells. Taken together, our results provide a plausible, exosome-based mechanistic explanation for the immune dysfunction and the compromised immune surveillance in endometriosis and contribute novel insights into the pathogenesis of this enigmatic disease.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":" ","pages":"567-576"},"PeriodicalIF":3.6,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11335327/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141563511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ICOS-expressing Regulatory T Cells Influence the Composition of Antitumor CTL Populations.","authors":"Nikoletta Diamantopoulos, Joanna Li, Antoine Bouchard, Loick Joumier, Saba Mohammaei, Vincent Panneton, Jinsam Chang, Mohan Malleshaiah, Woong-Kyung Suh","doi":"10.4049/jimmunol.2300154","DOIUrl":"10.4049/jimmunol.2300154","url":null,"abstract":"<p><p>The role of ICOS in antitumor T cell responses and overall tumor progression has been controversial. In this study, we compared tumor progression in mice lacking ICOS selectively in regulatory T (Treg) cells or in all T cells. Using an experimental melanoma lung metastasis model, we found that Treg cell-specific ICOS knockout reduces the overall tumor burden compared with Cre control mice, with increased CD4+-to-Treg cell and CD8+-to-Treg cell ratios in the tumor. In contrast, there was no difference in the tumor burden in mice lacking ICOS in all of the T cell compartments. This suggests a dual role of ICOS costimulation in promoting protumor and antitumor T cell responses. Consistent with reduced tumor burden, we found that Treg cell-specific deletion of ICOS leads to an increase of CD8+ CTLs that express high levels of granzyme B and perforin. Moreover, single-cell transcriptome analysis revealed an increase of Ly108+Eomeshi CD8+ T cells at the cost of the Ly108+T-bethi subset in Treg cell-specific knockout mice. These results suggest that ICOS-expressing Treg cells suppress the CTL maturation process at the level of Eomes upregulation, a critical step known to drive perforin expression and cytotoxicity. Collectively, our data imply that cancer immunotherapies using ICOS agonist Abs may work better in Treg cell-low tumors or when they are combined with regimens that deplete tumor-infiltrating Treg cells.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":" ","pages":"753-762"},"PeriodicalIF":3.6,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141590459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stabilization of β-Catenin Directs HEB to Limit Thymic Selection.","authors":"Georgios Tousinas, Akinola Olumide Emmanuel, Melissa Tracy, Stephen Arnovitz, David Friedman, Thomais Papamarcaki, Fotini Gounari","doi":"10.4049/jimmunol.2400160","DOIUrl":"10.4049/jimmunol.2400160","url":null,"abstract":"<p><p>Activation of β-catenin in CD4+CD8+ double-positive (DP) thymocytes halts development before the thymic selection stage and predisposes to transformation. Leukemogenesis, but not the developmental block, depends on TCF-1, β-catenin's DNA-binding partner. In this study, we show that β-catenin activation directs the DNA-binding protein HEB to block DP thymocyte development. Conditional loss of HEB in DP thymocytes with stabilized β-catenin restores the frequencies of postselection TCRβhi/CCR7+ and TCRβhi/CD69+ DPs and their cell-cycle profile. This recovery is associated with significant reversal of β-catenin-induced expression changes, particularly those related to the CD69+ DP cell signature and to cell-cycle pathways. Stabilizing β-catenin in DP thymocytes directs HEB binding to ≈11,000 novel DNA sites throughout the genome. Novel HEB sites mark most CD69+ DP cell signature genes that change expression upon activation of β-catenin and then revert after loss of HEB. Moreover, many of the novel HEB sites occupy promoter regions of genes enriched in mitotic cell cycle pathways. HEB binding to those regions correlates with downregulation of the associated genes, and HEB inactivation restores expression to physiologic levels. These findings highlight a molecular interplay between HEB and β-catenin that can impair thymic development.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":" ","pages":"641-650"},"PeriodicalIF":3.6,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11333165/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141492317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction: Top Reads.","authors":"","doi":"10.4049/jimmunol.2400459","DOIUrl":"https://doi.org/10.4049/jimmunol.2400459","url":null,"abstract":"<p><p>Top Reads. 2024. J. Immunol. 213:245. A third summary for the article titled \"Obesity inhibits alveolar macrophage responses to Pseudomonas aeruginosa pneumonia via upregulation of PGE2 in male, but not female mice\" by Gabrielle P. Entrup, Aayush Unadkat, Helen I. Warheit-Niemi, Brooke Thomas, Stephen J. Gurczynski, Yuxiao Cui, Andrew M. Smith, Katherine A. Gallagher, Bethany B. Moore, and Kanakadurga Singer was inadvertently excluded from the Top Reads' summary in the August 1, 2024 issue and appears below. Obesity Inhibits Alveolar Macrophage Responses to Pneumonia Obesity is associated with increased morbidity and mortality during bacterial pneumonia. Cyclooxygenase-2 (COX-2) and PGE2 have been shown to be upregulated in patients who are obese. In this study, we investigated the role of obesity and PGE2 in bacterial pneumonia and how inhibition of PGE2 improves antibacterial functions of macrophages. C57BL/6J male and female mice were fed either a normal diet (ND) or high-fat diet (HFD) for 16 wk. After this time, animals were infected with Pseudomonas aeruginosa in the lung. In uninfected animals, alveolar macrophages were extracted for either RNA analysis or to be cultured ex vivo for functional analysis. HFD resulted in changes in immune cell numbers in both noninfected and infected animals. HFD animals had increased bacterial burden compared with ND animals; however, male HFD animals had higher bacterial burden compared with HFD females. Alveolar macrophages from HFD males had decreased ability to phagocytize and kill bacteria and were shown to have increased cyclooxygenase-2 and PGE2. Treating male, but not female, alveolar macrophages with PGE2 leads to increases in cAMP and decreased bacterial phagocytosis. Treatment with lumiracoxib-conjugated nanocarriers targeting alveolar macrophages improves bacterial phagocytosis and clearance in both ND and HFD male animals. Our study highlights that obesity leads to worse morbidity during bacterial pneumonia in male mice because of elevated PGE2. In addition, we uncover a sex difference in both obesity and infection, because females produce high basal PGE2 but because of a failure to signal via cAMP do not display impaired phagocytosis. This has been corrected in the online version of the article, which now differs from the print version as originally published.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":" ","pages":""},"PeriodicalIF":3.6,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142043948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}