Browsing by Author "Yu, Qigui"

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    Alcohol abstinence ameliorates the dysregulated immune profiles in patients with alcoholic hepatitis: A prospective observational study
    (Wiley, 2017) Li, Wei; Amet, Tohti; Xing, Yanyan; Yang, Dennis; Liangpunsakul, Suthat; Puri, Puneet; Kamath, Patrick; Sanyal, Arun; Shah, Vijay; Katz, Barry; Radaeva, Svetlana; Crabb, David; Chalasani, Naga; Yu, Qigui; Department of Microbiology and Immunology, IU School of Medicine
    Alcoholic hepatitis (AH) develops in only a small proportion of heavy drinkers. To better understand the mechanisms underlying this disparity, we conducted a study to define the relationship between AH development and dysregulated immune responses that might be ameliorated by alcohol abstinence. Sixty-eight AH patients, 65 heavy drinking controls without liver disease (HDC), and 20 healthy controls were enrolled and followed up to 12 months. At baseline, HDC and healthy controls had no significant differences in their plasma levels of 38 inflammatory cytokines/chemokines measured using multiplex immunoassays. However, compared to HDC, AH patients had higher baseline levels of 11 cytokines/chemokines (tumor necrosis factor alpha, interleukin 6 [IL-6], IL-8, interferon gamma–induced protein 10, IL-4, IL-9, IL-10, fibroblast growth factor 2, IL-7, IL-15, and transforming growth factor alpha) but lower levels of the anti-inflammatory macrophage-derived chemokine. AH patients also had more activated yet dysfunctional immune cells as monocytes, T cells, and B cells expressed higher levels of cluster of differentiation 38 (CD38) and CD69 but low levels of human leukocyte antigen DR, CD80, and CD86 at baseline. In addition, CD4 T cells produced less interferon-gamma in response to T-cell stimulation. Up-regulated IL-6, IL-8, CD38, and CD69 and down-regulated macrophage-derived chemokine, human leukocyte antigen DR, CD86, and CD80 correlated positively and negatively, respectively, with disease severity. Longitudinal analysis indicated that levels of IL-6, IL-8, CD38, and CD69 were reduced, whereas levels of macrophage-derived chemokine, human leukocyte antigen DR, CD80, and CD86 were increased in abstinent AH patients. All of the cellular immune abnormalities were reversed by day 360 in abstinent AH patients; however, plasma levels of tumor necrosis factor alpha, IL-8, IL-10, fibroblast growth factor 2, and IL-7 remained higher. Conclusion: AH patients were in a highly immune-dysregulated state, whereas HDC showed little evidence of immune activation; alcohol abstinence reversed most, but not all, of the immunological abnormalities.
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    Alcohol Abstinence Does Not Fully Reverse Abnormalities of Mucosal-Associated Invariant T Cells in the Blood of Patients With Alcoholic Hepatitis
    (Wolters Kluwer, 2019-06) Li, Wei; Lin, Edward L.; Liangpunsakul, Suthat; Lan, Jie; Chalasani, Sai; Rane, Sushmita; Puri, Puneet; Kamath, Patrick S.; Sanyal, Arun J.; Shah, Vijay H.; Radaeva, Svetlana; Crabb, David W.; Chalasani, Naga; Yu, Qigui; Microbiology & Immunology, IU School of Medicine
    OBJECTIVES: Alcoholic hepatitis (AH) develops in approximately 30% of chronic heavy drinkers. The immune system of patients with AH is hyperactivated, yet ineffective against infectious diseases. Mucosal-associated invariant T (MAIT) cells are innate-like lymphocytes that are highly enriched in liver, mucosa, and peripheral blood and contribute to antimicrobial immunity. We aimed to determine whether MAIT cells were dysregulated in heavy drinkers with and without AH and the effects of alcohol abstinence on MAIT cell recovery. METHODS: MR1 tetramers loaded with a potent MAIT cell ligand 5-(2-oxopropylideneamino)-6-d-ribitylaminouracil were used in multiparameter flow cytometry to analyze peripheral blood MAIT cells in 59 healthy controls (HC), 56 patients with AH, and 45 heavy drinkers without overt liver disease (HDC) at baseline and 6- and 12-month follow-ups. Multiplex immunoassays were used to quantify plasma levels of cytokines related to MAIT cell activation. Kinetic Turbidimetric Limulus Amebocyte Lysate Assay and ELISA were performed to measure circulating levels of 2 surrogate markers for bacterial translocation (lipopolysaccharide and CD14), respectively. RESULTS: At baseline, patients with AH had a significantly lower frequency of MAIT cells than HDC and HC. HDC also had less MAIT cells than HC (median 0.16% in AH, 0.56% in HDC, and 1.25% in HC). Further, the residual MAIT cells in patients with AH expressed higher levels of activation markers (CD69, CD38, and human leukocyte antigen [HLA]-DR), the effector molecule granzyme B, and the immune exhaustion molecule PD-1. Plasma levels of lipopolysaccharide and CD14 and several cytokines related to MAIT cell activation were elevated in patients with AH (interferon [IFN]-α, interleukin [IL]-7, IL-15, IL-17, IL-18, IL-23, IFN-γ, and tumor necrosis factor α). Decreased MAIT cell frequency and upregulated CD38, CD69, and HLA-DR correlated negatively and positively, respectively, with aspartate aminotransferase level. MAIT cell frequency negatively correlated with IL-18. HLA-DR and CD38 levels correlated with several cytokines. At follow-ups, abstinent patients with AH had increased MAIT cell frequency and decreased MAIT cell activation. However, MAIT cell frequency was not fully normalized in patients with AH (median 0.31%). DISCUSSION: We showed that HDC had a reduction of blood MAIT cells despite showing little evidence of immune activation, whereas patients with AH had a severe depletion of blood MAIT cells and the residual cells were highly activated. Alcohol abstinence partially reversed those abnormalities.
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    AMP kinase promotes Bcl6 expression in both mouse and human T cells
    (Elsevier, 2017-01) Xie, Markus M.; Amet, Tohti; Liu, Hong; Yu, Qigui; Dent, Alexander L.; Department of Microbiology and Immunology, School of Medicine
    The transcription factor Bcl6 is a master regulator of follicular helper T (TFH) cells, and understanding the signaling pathway that induces Bcl6 and TFH cell differentiation is therefore critical. IL-2 produced during T cell activation inhibits Bcl6 expression but how TFH cells evade IL-2 inhibition is not completely understood. Here we show that Bcl6 is highly up-regulated in activated CD4 T cells following glucose deprivation (GD), and this pathway is insensitive to inhibition by IL-2. Similar to GD, the glucose analog 2-deoxyglucose (2DG) inhibits glycolysis, and 2DG induced Bcl6 expression in activated CD4 T cells. The metabolic sensor AMP kinase (AMPK) is activated when glycolysis is decreased, and the induction of Bcl6 by GD was inhibited by the AMPK antagonist compound C. Additionally, activation of AMPK by the drug AICAR caused Bcl6 up-regulation in activated CD4 T cells. When mice were immunized with KLH using AICAR as an adjuvant, there was a strong TFH–dependent enhancement of KLH-specific antibody (Ab) responses, and higher Bcl6 expression in TFH cells in vivo. Activation of AMPK strongly induced BCL6 and the up-regulation of TFH cell marker expression by human CD4 T cells. Our data reveal a major new pathway for TFH cell differentiation, conserved by both mouse and human T cells. Mature TFH cells are reported to have a lower metabolic state compared to TH1 cells. Our data indicates that decreased metabolism may be deterministic for TFH cell differentiation, and not simply a result of TFH cell differentiation.
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    Antiretroviral Therapy Normalizes Autoantibody Profile of HIV Patients by Decreasing CD33⁺CD11b⁺HLA-DR⁺ Cells: A Cross-Sectional Study
    (Ovid Technologies (Wolters Kluwer) - Lippincott Williams & Wilkins, 2016-04) Meng, Zhefeng; Du, Ling; Hu, Ningjie; Byrd, Daniel; Amet, Tohti; Desai, Mona; Shepherd, Nicole; Lan, Jie; Han, Renzhi; Yu, Qigui; Department of Microbiology & Immunology, IU School of Medicine
    Autoimmune manifestations are common in human immunodeficiency virus (HIV) patients. However, the autoantibody spectrum associated with HIV infection and the impact of antiretroviral therapy (ART) remains to be determined. The plasma autoantibody spectrum for HIV patients was characterized by protein microarrays containing 83 autoantigens and confirmed by enzyme-linked immunosorbent assay (ELISA). Regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) were analyzed by flow cytometry and their effects on autoantibodies production were determined by B cell ELISpot. Higher levels of autoantibody and higher prevalence of elevated autoantibodies were observed in ART-naive HIV patients compared to healthy subjects and HIV patients on ART. The highest frequency of CD33(+)CD11b(+)HLA-DR(+) cells was observed in ART-naive HIV patients and was associated with the quantity of elevated autoantibodies. In addition, CD33(+)CD11b(+)HLA-DR(+) cells other than Tregs or MDSCs boost the B cell response in a dose-dependent manner by in vitro assay. In summary, HIV infection leads to elevation of autoantibodies while ART suppresses the autoimmune manifestation by decreasing CD33(+)CD11b(+)HLA-DR(+) cells in vivo.The roles of CD33(+)CD11b(+)HLA-DR(+) cells on disease progression in HIV patients needs further assessment.
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    BCL6 represses antiviral resistance in follicular T helper cells
    (Wiley, 2017-08) Amet, Tohti; Son, Young Min; Jiang, Li; Cheon, In Su; Huang, Su; Gupta, Samir K.; Dent, Alexander L.; Montaner, Luis J.; Yu, Qigui; Sun, Jie; Microbiology and Immunology, School of Medicine
    Follicular Th (Tfh) cells are a distinct subset of Th cells that help B cells produce class-switched antibodies. Studies have demonstrated that Tfh cells are highly prone to HIV infection and replication. However, the molecular mechanisms underlying this phenomenon are largely unclear. Here, we show that murine and human Tfh cells have diminished constitutive expression of IFN-stimulated genes (ISGs) inclusive of antiviral resistance factor MX dynamin-like GTPase 2 (MX2) and IFN-induced transmembrane 3 (IFITM3) compared with non-Tfh cells. A lower antiviral resistance in Tfh was consistent with a higher susceptibility to retroviral infections. Mechanistically, we found that BCL6, a master regulator of Tfh cell development, binds to ISG loci and inhibits the expression of MX2 and IFITM3 in Tfh cells. We demonstrate further that inhibition of the BCL6 BR-C, ttk, and bab (BTB) domain function increases the expression of ISGs and suppresses HIV infection and replication in Tfh cells. Our data reveal a regulatory role of BCL6 in inhibiting antiviral resistance factors in Tfh cells, thereby promoting the susceptibility Tfh cells to viral infections. Our results indicate that the modulation of BCL6 function in Tfh cells could be a potential strategy to enhance Tfh cell resistance to retroviral infections and potentially decrease cellular reservoirs of HIV infection.
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    Blood Biomarkers of Intestinal Epithelium Damage Regenerating Islet-derived Protein 3α and Trefoil Factor 3 Are Persistently Elevated in Patients with Alcoholic Hepatitis
    (Wiley, 2021) Yang, Jing; Syed, Fahim; Xia, Ying; Sanyal, Arun; Shah, Vijay; Chalasani, Naga; Zheng, Xiaoqun; Yu, Qigui; Lou, Yongliang; Li, Wei; Microbiology and Immunology, School of Medicine
    Background: Heavy alcohol consumption disrupts gut epithelial integrity, leading to increased permeability of the gastrointestinal tract and subsequent translocation of microbes. Regenerating islet-derived protein 3α (REG3α) and Trefoil factor 3 (TFF3) are mainly secreted to the gut lumen by Paneth and Goblet cells, respectively, and are functionally linked to gut barrier integrity. Circulating levels of REG3α and TFF3 have been identified as biomarkers for gut damage in several human diseases. We examined whether plasma levels of REG3α and TFF3 were dysregulated and correlated with conventional markers of microbial translocation (MT) and pro-inflammatory mediators in heavy drinkers with and without alcoholic hepatitis (AH). Methods: Cross-sectional and longitudinal studies were performed to monitor plasma levels of REG3α and TFF3 in 79 AH patients, 66 heavy drinkers without liver disease (HDC), and 46 healthy controls (HC) at enrollment and at 6- and 12-month follow-ups. Spearman correlation was used to measure the relationships of REG3α and TFF3 levels with MT, disease severity, inflammation, and effects of abstinence from alcohol. Results: At enrollment, AH patients had significantly higher levels of REG3α and TFF3 than HDC and HC. The elevated REG3α levels were positively correlated with the 30-day fatality rate. Plasma levels of REG3α and TFF3 in AH patients differentially correlated with conventional MT markers (sCD14, sCD163, and LBP) and several highly up-regulated inflammatory cytokines/chemokines/growth factors. At follow-ups, although REG3α and TFF3 levels were decreased in AH patients with alcohol abstinence, they did not fully return to baseline levels. Conclusions: Circulating levels of REG3α and TFF3 were highly elevated in AH patients and differentially correlated with AH disease severity, MT, and inflammation, thereby serving as potential biomarkers of MT and gut epithelial damage in AH patients.
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    Cell-to-cell transmission of HIV-1 from provirus-activated cells to resting naïve and memory human primary CD4 T cells is highly efficient and requires CD4 and F-actin but not chemokine receptors
    (Wiley, 2022) Lan, Jie; Li, Wei; Yu, Richard; Syed, Fahim; Yu, Qigui; Microbiology and Immunology, School of Medicine
    Latently infected cells harboring replication-competent proviruses represent a major barrier to HIV-1 cure. One major effort to purge these cells has focused on developing the "shock and kill" approach for forcing provirus reactivation to induce cell killing by viral cytopathic effects, host immune responses, or both. We conducted kinetic and mechanistic studies of HIV-1 protein expression, virion production, and cell-to-cell virus transmission during provirus reactivation. Provirus-activated ACH-2 cells stimulated with romidepsin (RMD) or PMA produced Nef early, and then Env and Gag in parallel with the appearance of virions. Env on the surface of provirus-activated cells and cellular F-actin were critical in the formation of virological synapses to mediate cell-to-cell transmission of HIV-1 from provirus-activated cells to uninfected cells. This HIV-1 cell-to-cell transmission was substantially more efficient than transmission seen via cell-free virus spread and required F-actin remodeling and CD4, but not chemokine receptors. Resting human primary CD4+ T cells including naïve and memory subpopulations and, especially the memory CD4+ T cells, were highly susceptible to HIV-1 infection via cell-to-cell transmission. Cell-to-cell transmission of HIV-1 from provirus-activated cells was profoundly decreased by protease inhibitors (PIs) and neutralizing antibodies (nAbs) that recognize the CD4-binding site (CD4bs) such as VRC01, but not by reverse transcriptase (RT) inhibitor Emtricitabine (FTC). Therefore, our results suggest that PIs with potent blocking abilities should be used in clinical application of the "shock and kill" approach, most likely in combination with CD4bs nAbs, to prevent new HIV-1 infections.
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    The circulating microbiome signature and inferred functional metagenomics in alcoholic hepatitis
    (Wiley, 2017) Puri, Puneet; Liangpunsakul, Suthat; Christensen, Jeffrey E.; Shah, Vijay H.; Kamath, Patrick S.; Gores, Gregory J.; Walker, Susan; Comerford, Megan; Katz, Barry; Borst, Andrew; Yu, Qigui; Kumar, Divya P.; Mirshahi, Faridoddin; Radaeva, Svetlana; Chalasani, Naga P.; Crabb, David W.; Sanyal, Arun J.; Medicine, School of Medicine
    Intestinal dysbiosis is implicated in alcoholic hepatitis (AH). However, changes in the circulating microbiome, its association with the presence and severity of AH and its functional relevance in AH is unknown. Qualitative and quantitative assessment of changes in the circulating microbiome were performed by sequencing bacterial DNA in subjects with moderate (n=18) or severe AH (n=19). These data were compared to heavy drinking controls (HDC) without obvious liver disease (n=19) and non-alcohol consuming controls (NAC, n=20). The data were related to endotoxin levels and markers of monocyte activation. Linear Discriminant Analysis (LDA) Effect Size (LEfSe) analysis, inferred metagenomics and predictive functional analysis using PICRUSt were performed. There was a significant increase in 16S copies/ng DNA both in MAH (p<0.01) and SAH (p<0.001) subjects. Compared to NAC, the relative abundance of phylum Bacteroidetes was significantly decreased in HDC, MAH, and SAH (p<0.001). In contrast, all alcohol consuming groups had enrichment with Fusobacteria; this was greatest for HDC and decreased progressively in MAH and SAH. Subjects with SAH had significantly higher endotoxemia (p=0.01). Compared to alcohol consuming groups, predictive functional metagenomics indicated an enrichment of bacteria with genes related to methanogenesis and denitrification. Also, both HDC and SAH showed activation of type III secretion system which has been linked to gram negative bacterial virulence. Metagenomics in SAH vs NAC predicted increased isoprenoid synthesis via mevalonate and anthranilate degradation, known modulators of gram positive bacterial growth and biofilm production respectively. In conclusion, heavy alcohol consumption appears to be the primary driver of changes in the circulating microbiome associated with a shift in its inferred metabolic functions.
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    Disrupted balance between pro-inflammatory lipid mediators and anti-inflammatory specialized pro-resolving mediators is linked to hyperinflammation in patients with alcoholic hepatitis
    (Frontiers Media, 2024-11-21) Li, Wei; Xia, Ying; Yang, Jing; Sanyal, Arun J.; Shah, Vijay H.; Chalasani, Naga P.; Yu, Qigui; Microbiology and Immunology, School of Medicine
    Background: Alcoholic hepatitis (AH) is characterized by intense systemic and liver inflammation, posing significant risks of health complications and mortality. While inflammation is a crucial defense mechanism against injury and infection, its timely resolution is essential to prevent tissue damage and restore tissue homeostasis. The resolution of inflammation is primarily governed by specialized pro-resolving mediators (SPMs), lipid metabolites derived from w-6 and w-3 poly-unsaturated fatty acids (PUFAs). Currently, the balance between pro-inflammatory lipid mediators (PLMs) and SPMs in the w-6 and w-3 PUFA metabolic pathways and the impact of alcohol abstinence on profiles of PLMs and SPMs in AH patients are not well studied. Methods: In this study, we used LC-MS/MS and ELISA to quantify levels of lipid mediators (LMs) and their precursors in the plasma samples from 58 AH patients, 29 heavy drinkers without overt liver diseases (HDCs), and 35 healthy controls (HCs). Subsequently, we assessed correlations of altered LMs with clinical parameters and inflammatory mediators. Furthermore, we conducted a longitudinal study to analyze the effects of alcohol abstinence on LMs over 6- and 12-month follow-ups. Results: AH patients exhibited significantly higher plasma levels of w-6 PLMs (PGD2 and LTB4) and SPM RvE1 compared to HDCs or HCs. Conversely, the SPM LXA4 was significantly downregulated in AH patients. Some of these altered LMs were found to correlate with AH disease severity and various inflammatory cytokines. Particularly, the LTB4/LXA4 ratio was substantially elevated in AH patients relative to HDCs and HCs. This altered ratio displayed a positive correlation with the MELD score. Importantly, the majority of dysregulated LMs, particularly PLMs, were normalized following alcohol abstinence.