Publications

BACKGROUND: Mucosal-associated invariant T (MAIT) cells are innate-like lymphocytes enriched in mucosal tissues, but their role in allergic asthma pathogenesis remains poorly defined. In this study, we sought to elucidate the role of MAIT cells in a T cell-dominant model of allergic asthma.

METHODS: We used a murine model of house dust mite-induced asthma and a selective MAIT cell antagonist (Acetyl-6-formylpterin, A6FP) to inhibit MAIT cell activation in vivo. Airway hyperresponsiveness, lung inflammation, serum IgE, and cytokine profiles were assessed. In vitro co-culture experiments evaluated the direct impact of MAIT cells on B cell IgE production.

RESULTS: Pharmacologic inhibition of MAIT cells exacerbated airway hyperresponsiveness and elevated circulating IgE without altering airway eosinophilia or T helper type 2/type 17 cytokine production. MAIT cell antagonism failed to increase AHR in IgE-deficient mice. In vitro, activated MAIT cells directly suppressed B cell IgE production through IFNγ signaling. IL-4 was sufficient to enhance IFNγ production by MAIT cells, suggesting that allergic inflammation may induce a counter-regulatory response from MAIT cells to limit IgE-mediated pathology.

CONCLUSION: MAIT cells limit airway hyperresponsiveness by suppressing IgE production through IFNγ-dependent B cell regulation. These findings define a previously unrecognized immunoregulatory function of MAIT cells in allergic asthma and suggest that enhancing MAIT cell activity may represent a therapeutic strategy for IgE-mediated diseases.

Unlike conventional T cells that detect peptide antigens loaded to major histocompatibility complex (MHC) molecules, unconventional T cells respond to non-peptidic metabolite antigens presented by MHC class I-like proteins, such as CD1 and MHC-related protein 1 (MR1). Semi-invariant mucosal-associated invariant T (MAIT) cells, γδ T cells, and invariant natural killer T (iNKT) cells, together with other CD1- or MR1-restricted T cell subsets expressing diverse T cell receptors (TCR), elicit an innate-like response independent of diverse MHC genetics. In contrast to an overall enhanced response to bacterial-derived riboflavin precursor metabolites in infections, MAIT cells often exhibit an immunosuppressive or exhausted phenotype in glioblastoma, lung cancer, colorectal cancer, and various hematological malignancies. Whereas some tumor cells can activate MAIT cells, the structures and functions of tumor-derived MR1 ligands remain largely unknown. Novel discoveries of mammalian-derived agonists and antagonists binding to MR1 protein are our knowledge of MR1 ligand structures and functions from MAIT cell activation in healthy conditions to anti-cancer immunity. Recent findings reveal that nucleoside and nucleobase analogs, as self-metabolites to activate MR1-restricted T cells, are regulated in the tumor microenvironment. Likewise, iNKT cells exhibit a dynamic role in cancer, capable of both protumor and antitumor immunity. Similarly, γδ T cells have also demonstrated both protective and tumor-promoting roles, via recognizing stress-induced protein and metabolite ligands. This review further depicts the distinct kinetics of responses, highlighting a rapid activation of unconventional T cells in solid versus hematological cancers. Emerging therapeutic strategies, including antigen-loaded MR1 and CD1, adoptive T cell transfer, chimeric antigen receptor-T (CAR-T) cells, T cell receptor-T (TCR-T) cells, and combination treatments with immune checkpoint inhibitors, yet remain challenging, hold promise in overcoming tumor-induced immunosuppression and genetic restriction of conventional T cell therapies. By addressing critical gaps, such as novel structures and functions of cancer metabolite antigens, unconventional T cells offer unique advantages in anti-cancer immunotherapy.

The placenta is vital for fetal growth, and its methylation patterns reflect placental function, affecting the fetus and providing insights into disease origins. While cord blood methylation is convenient for assessing the fetal environment, methylation profiles vary by tissue due to variance in cell populations, function, and life stage. As tissue differences extensively contribute to the DNA methylation patterns, using surrogate samples such as cord blood may result in inconsistent findings. In this study, we aim to quantify the correlation of cytosine-phosphate-guanine dinucleotides (CpGs) between paired cord blood and placenta samples. Using the Infinium Human Methylation 450 K BeadChip, we compared methylation patterns in cord blood mononuclear cells (CBMC; n = 54), the maternally-facing side of placental tissue (MP; n = 68), and the fetal-facing side of placental tissue (FP; n = 67). Methylation patterns from the FP (6,021 CpGs) were significantly correlated with CBMC compared to the MP (2,862 CpGs). These CpGs were related to the biological (mitotic cell) process and molecular function (ribonucleoprotein complex binding). Our findings quantified CpG site correlation between cord blood and placenta, providing a valuable reference for future studies on placental health that rely on cord blood methylation in the absence of placental biospecimens.

BACKGROUND: Gestational exposure to non-persistent endocrine-disrupting chemicals (EDCs) may be associated with adverse pregnancy outcomes. While many EDCs affect the endocrine system, their effects on endocrine-related metabolic pathways remain unclear. This study aims to explore the global metabolome changes associated with EDC biomarkers at delivery.

METHODS: This study included 75 pregnant individuals who delivered at the University of Cincinnati Hospital from 2014 to 2017. We measured maternal urinary biomarkers of paraben/phenol (12), phthalate (13), and phthalate replacements (4) from the samples collected during the delivery visit. Global serum metabolome profiles were analyzed from maternal blood (n = 72) and newborn (n = 63) cord blood samples collected at delivery. Fifteen of the 29 urinary biomarkers were excluded due to low detection frequency or potential exposures during hospital stay. We assessed metabolome-wide associations between 14 maternal urinary biomarkers and maternal/newborn metabolome profiles. Additionally, performed enrichment analysis to identify potential alterations in metabolic pathways.

RESULTS: We observed metabolome-wide associations between maternal urinary concentrations of phthalate metabolites (mono-isobutyl phthalate), phthalate replacements (mono-2-ethyl-5-carboxypentyl terephthalate, mono-2-ethyl-5-hydroxyhexyl terephthalate) and phenols (bisphenol-A, bisphenol-S) and maternal serum metabolome, using q-value < 0.2 as a threshold. Additionally, associations of phthalate metabolites (mono-n-butyl phthalate, monobenzyl phthalate) and phenols (2,5-dichlorophenol, BPA) with the newborn metabolome were noted. Enrichment analyses revealed associations (p-gamma < 0.05) with amino acid, carbohydrate, lipid, glycan, vitamin, and other cofactor metabolism pathways.

CONCLUSION: Maternal paraben, phenol, phthalate, and phthalate replacement biomarker concentrations at delivery were associated with maternal and newborn serum global metabolome.

Method: This study included 75 pregnant individuals who planned to give birth at the University of Cincinnati Hospital between 2014 and 2017. Maternal urine samples during the delivery visit were collected and analyzed for 37 biomarkers of phenols (12), phthalates (13), phthalate replacements (4), and PAHs (8). Cord blood and placenta tissue (maternal and fetal sides) were also collected to measure the DNA methylation intensities using the Infinium HumanMethylation450K BeadChip. We used linear regression, adjusting for potential confounders, to assess CpG-specific methylation changes in CBMC (n = 54) and placenta [fetal (n = 67) and maternal (n = 68) sides] associated with gestational chemical exposures (29 of 37 biomarkers measured in this study). To account for multiple testing, we used a false discovery rate q-values < 0.05 and presented results by limiting results with a genomic inflation factor of 1±0.5. Additionally, gene set enrichment analysis was conducted using the Kyoto Encyclopedia of Genes and Genomics pathways.

Results: Among the 29 chemical biomarkers assessed for differential methylation, maternal concentrations of PAH metabolites (1-hydroxynaphthalene, 2-hydroxyfluorene, 4-hydroxyphenanthrene, 1-hydroxypyrene), monocarboxyisononyl phthalate, mono-3-carboxypropyl phthalate, and bisphenol A were associated with altered methylation in placenta (maternal or fetal side). Among exposure biomarkers associated with epigenetic changes, 1-hydroxynaphthalene, and mono-3-carboxypropyl phthalate were consistently associated with differential CpG methylation in the placenta. Gene enrichment analysis indicated that maternal 1-hydroxynaphthalene was associated with lipid metabolism and cellular processes of the placenta. Additionally, mono-3-carboxypropyl phthalate was associated with organismal systems and genetic information processing of the placenta.

Conclusion: Among the 29 chemical biomarkers assessed during delivery, 1-hydroxynaphthalene and mono-3-carboxypropyl phthalate were associated with DNA methylation in the placenta.

Mucosal-associated invariant T (MAIT) cells are protective against tuberculous and non-tuberculous mycobacterial infections with poorly understood mechanisms. Despite an innate-like nature, MAIT cell responses remain heterogeneous in bacterial infections. To comprehensively characterize MAIT activation programs responding to different bacteria, we stimulated MAIT cells with E. coli to compare with Bacillus Calmette-Guérin (BCG), which remains the only licensed vaccine and a feasible tool for investigating anti-mycobacterial immunity in humans. Upon sequencing mRNA from the activated and inactivated CD8+ MAIT cells, results demonstrated the altered MAIT cell gene profiles by each bacterium with upregulated expression of activation markers, transcription factors, cytokines, and cytolytic mediators crucial in anti-mycobacterial responses. Compared with E. coli, BCG altered more MAIT cell genes to enhance cell survival and cytolysis. Flow cytometry analyses similarly displayed a more upregulated protein expression of B-cell lymphoma 2 and T-box transcription factor Eomesodermin in BCG compared to E.coli stimulations. Thus, the transcriptomic program and protein expression of MAIT cells together displayed enhanced pro-survival and cytotoxic programs in response to BCG stimulation, supporting BCG induces cell-mediated effector responses of MAIT cells to fight mycobacterial infections.

The CD1 system binds lipid antigens for display to T cells. Here, we solved lipidomes for the four human CD1 antigen-presenting molecules, providing a map of self-lipid display. Answering a basic question, the detection of >2,000 CD1-lipid complexes demonstrates broad presentation of self-sphingolipids and phospholipids. Whereas peptide antigens are chemically processed, many lipids are presented in an unaltered form. However, each type of CD1 protein differentially edits the self-lipidome to show distinct capture motifs based on lipid length and chemical composition, suggesting general antigen display mechanisms. For CD1a and CD1d, lipid size matches the CD1 cleft volume. CD1c cleft size is more variable, and CD1b is the outlier, where ligands and clefts show an extreme size mismatch that is explained by uniformly seating two small lipids in one cleft. Furthermore, the list of compounds that comprise the integrated CD1 lipidome supports the ongoing discovery of lipid blockers and antigens for T cells.

INTRODUCTION: Prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) has been associated with adverse human health outcomes. To explore the plausible associations between maternal PAH exposure and maternal/newborn metabolomic outcomes, we conducted a cross-sectional study among 75 pregnant people from Cincinnati, Ohio.

METHOD: We quantified 8 monohydroxylated PAH metabolites in maternal urine samples collected at delivery. We then used an untargeted high-resolution mass spectrometry approach to examine alterations in the maternal (n = 72) and newborn (n = 63) serum metabolome associated with PAH metabolites. Associations between individual maternal urinary PAH metabolites and maternal/newborn metabolome were assessed using linear regression adjusted for maternal and newborn factors while accounting for multiple testing with the Benjamini-Hochberg method. We then conducted functional analysis to identify potential biological pathways.

RESULTS: Our results from the metabolome-wide associations (MWAS) indicated that an average of 1% newborn metabolome features and 2% maternal metabolome features were associated with maternal urinary PAH metabolites. Individual PAH metabolite concentrations in maternal urine were associated with maternal/newborn metabolome related to metabolism of vitamins, amino acids, fatty acids, lipids, carbohydrates, nucleotides, energy, xenobiotics, glycan, and organic compounds.

CONCLUSION: In this cross-sectional study, we identified associations between urinary PAH concentrations during late pregnancy and metabolic features associated with several metabolic pathways among pregnant women and newborns. Further studies are needed to explore the mediating role of the metabolome in the relationship between PAHs and adverse pregnancy outcomes.

BACKGROUND: Severe neutrophilic asthma is often characterized by persistent airway inflammation and irreversible airway remodeling, which are overstimulated by the high-mobility group box protein 1 (HMGB1). Although wogonin, an O-methylated flavone, has been widely used to treat inflammatory and allergic diseases, its therapeutic effects and potential mechanisms on severe neutrophilic asthma remain elusive.

OBJECTIVE: To evaluate whether wogonin alleviates airway neutrophilia through inducing neutrophil apoptosis and attenuates airway smooth muscle cells (ASMCs) proliferation and migration.

METHODS: The effect of wogonin on reducing neutrophilic airway inflammation, including neutrophil infiltration and inflammatory mediators, was examined in a mouse model of severe neutrophilic asthma sensitized with ovalbumin and lipopolysaccharide. Also, the effect of wogonin on inducing human neutrophil apoptosis was manifested using cellular morphology, flow cytometry, and caspase inhibition assays. Furthermore, the effect of wogonin on inhibiting HMGB1-mediated ASMCs proliferation and migration was determined.

RESULTS: Wogonin reduced the frequency of neutrophils and inhibited the production of multiple inflammatory mediators, including ovalbumin-specific IgE, tumor necrosis factor-α, interleukin-6, and HMGB1, in bronchoalveolar lavage fluid and lung tissues of the neutrophilic asthmatic mouse model. These data strongly support a significantly suppressed neutrophilic airway inflammation, functionally consistent to the relieved airway hyperresponsiveness by wogonin in vivo. Wogonin induced human neutrophil apoptosis in a dose-dependent manner by activating caspase-8 and caspase-3 in vitro. Wogonin pretreatment abolished HMGB1-induced ASMCs proliferation and migration, which can be explained by the inhibition of phosphorylation in the mitogen-activated protein kinase (MAPK) /Akt singling pathways.

CONCLUSION: Our findings demonstrate that wogonin augments caspase-dependent apoptosis in neutrophils to alleviate neutrophilic inflammatory responses and regulates intracellular signaling to inhibit HMGB1-mediated ASMCs activation, providing a promising therapeutic agent for severe neutrophilic asthma.

Respiratory viruses are major human pathogens that cause approximately 200 million pneumonia cases annually and induce various comorbidities with chronic obstructive pulmonary disease (COPD), resulting in significant health concerns and economic burdens. Clinical manifestations in respiratory viral infections and inflammations vary from asymptomatic, mild, to severe, depending on host immune cell responses to pathogens and interactions with airway epithelia. We critically review the activation, effector, and regulation of T cells in respiratory virus infections and chronic inflammations associated with COPD. Crosstalk among T cells, innate immune cells, and airway epithelial cells is discussed as essential parts of pathogenesis and protection in viral infections and COPD. We emphasize the specificity of peptide antigens and the functional heterogeneity of conventional CD4+ and CD8+ T cells to shed some light on potential cellular and molecular candidates for the future development of therapeutics and intervention against respiratory viral infections and inflammations.