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author:("Xia, zhenghei")
1.  iNKT cells require TSC1 for terminal maturation and effector lineage fate decisions 
The Journal of Clinical Investigation  2014;124(4):1685-1698.
Terminal maturation of invariant NKT (iNKT) cells from stage 2 (CD44+NK1.1–) to stage 3 (CD44+NK1.1+) is accompanied by a functional acquisition of a predominant IFN-γ–producing (iNKT-1) phenotype; however, some cells develop into IL-17–producing iNKT (iNKT-17) cells. iNKT-17 cells are rare and restricted to a CD44+NK1.1– lineage. It is unclear how iNKT terminal maturation is regulated and what factors mediate the predominance of iNKT-1 compared with iNKT-17. The tumor suppressor tuberous sclerosis 1 (TSC1) is an important negative regulator of mTOR signaling, which regulates T cell differentiation, function, and trafficking. Here, we determined that mice lacking TSC1 exhibit a developmental block of iNKT differentiation at stage 2 and skew from a predominantly iNKT-1 population toward a predominantly iNKT-17 population, leading to enhanced airway hypersensitivity. Evaluation of purified iNKT cells revealed that TSC1 promotes T-bet, which regulates iNKT maturation, but downregulates ICOS expression in iNKT cells by inhibiting mTOR complex 1 (mTORC1). Furthermore, mice lacking T-bet exhibited both a terminal maturation defect of iNKT cells and a predominance of iNKT-17 cells, and increased ICOS expression was required for the predominance of iNKT-17 cells in the population of TSC1-deficient iNKT cells. Our data indicate that TSC1-dependent control of mTORC1 is crucial for terminal iNKT maturation and effector lineage decisions, resulting in the predominance of iNKT-1 cells.
PMCID: PMC3973110  PMID: 24614103
2.  Diacylglycerol Kinase Zeta Positively Controls the Development of iNKT-17 Cells 
PLoS ONE  2013;8(9):e75202.
Invariant natural killer T (iNKT) cells play important roles in bridging innate and adaptive immunity via rapidly producing a variety of cytokines. A small subset of iNKT cells produces IL-17 and is generated in the thymus during iNKT-cell ontogeny. The mechanisms that control the development of these IL-17-producing iNKT-17 cells (iNKT-17) are still not well defined. Diacylglycerol kinase ζ (DGKζ) belongs to a family of enzymes that catalyze the phosphorylation and conversion of diacylglycerol to phosphatidic acid, two important second messengers involved in signaling from numerous receptors. We report here that DGKζ plays an important role in iNKT-17 development. A deficiency of DGKζ in mice causes a significant reduction of iNKT-17 cells, which is correlated with decreased RORγt and IL-23 receptor expression. Interestingly, iNKT-17 defects caused by DGKζ deficiency can be corrected in chimeric mice reconstituted with mixed wild-type and DGKζ-deficient bone marrow cells. Taken together, our data identify DGKζ as an important regulator of iNKT-17 development through iNKT-cell extrinsic mechanisms.
PMCID: PMC3779165  PMID: 24073253
3.  All-trans retinoic acid attenuates airway inflammation by inhibiting Th2 and Th17 response in experimental allergic asthma 
BMC Immunology  2013;14:28.
Airway inflammation is mainly mediated by T helper 2 cells (Th2) that characteristically produce interleukin (IL)-4, IL-5, and IL-13. Epidemiological studies have revealed an inverse association between the dietary intake of vitamin A and the occurrence of asthma. Serum vitamin A concentrations are significantly lower in asthmatic subjects than in healthy control subjects. It has been reported that all-trans retinoic acid (ATRA), a potent derivative of vitamin A, regulates immune responses. However, its role in Th2-mediated airway inflammation remains unclear. We investigated the effects of ATRA in a mouse model of allergic airway inflammation.
We found that ATRA treatment attenuated airway inflammation and decreased mRNA levels of Th2- and Th17-related transcription factors. The data showed that airway inflammation coincided with levels of Th2- and Th17-related cytokines. We also showed that ATRA inhibited Th17 and promoted inducible regulatory T-cell differentiation, whereas it did not induce an obvious effect on Th2 differentiation in vitro. Our data suggest that ATRA may interfere with the in vivo Th2 responses via T-cell extrinsic mechanisms.
Administration of ATRA dramatically attenuated airway inflammation by inhibiting Th2 and Th17 differentiation and/or functions. ATRA may have potential therapeutic effects for airway inflammation in asthmatic patients.
PMCID: PMC3695807  PMID: 23800145
Asthma; All-trans retinoic acid; Th2; Th17; Regulatory T cells
4.  Synthesized OVA323-339MAP octamers mitigate OVA-induced airway inflammation by regulating Foxp3 T regulatory cells 
BMC Immunology  2012;13:34.
Antigen-specific immunotherapy (SIT) has been widely practiced in treating allergic diseases such as asthma. However, this therapy may induce a series of allergic adverse events during treatment. Peptide immunotherapy (PIT) was explored to overcome these disadvantages. We confirmed that multiple antigen peptides (MAPs) do not cause autoimmune responses, which led to the presumption that MAPs intervention could alleviate allergic airway inflammation without inducing adverse effects.
In this study, synthesized OVA323-339MAP octamers were subcutaneously injected into ovalbumin (OVA)-sensitized and -challenged Balb/c mice to observe its effect on allergic airway inflammation, Th2 immune response, and immune regulating function. It was confirmed that OVA sensitization and challenge led to significant peritracheal inflammatory, cell infiltration, and intensive Th2 response. Treatment of OVA323-339MAP octomers in the airway inflammation mice model increased CD4+CD25+Foxp3+ T regulatory (Treg) cells and their regulatory function in peripheral blood, mediastinal draining lymph nodes, and the spleen. Furthermore, OVA323-339MAP increased IL-10 levels in bronchial alveolar lavage fluid (BALF); up-regulated the expression of IL-10, membrane-bound TGF-β1, as well as Foxp3 in lung tissues; and up-regulated programmed death-1 (PD-1) and cytotoxic T lymphocyte associated antigen 4 (CTLA-4) on the surface of Treg cells. These results were further correlated with the decreased OVA specific immunoglobulin E (sIgE) level and the infiltration of inflammatory cells such as eosinophils and lymphocytes in BALF. However, OVA323-339 peptide monomers did not show any of the mentioned effects in the same animal model.
Our study indicates that OVA323-339MAP had significant therapeutic effects on mice allergic airway inflammation by regulating the balance of Th1/Th2 response through Treg cells in vivo.
PMCID: PMC3472185  PMID: 22769043
Allergic airway inflammation; Specific immunotherapy; Multiple antigen peptide
5.  OX40 Induces CCL20 Expression in the Context of Antigen Stimulation: An Expanding Role of Co-Stimulatory Molecules in Chemotaxis 
Cytokine  2010;50(3):253-259.
OX40 is an inducible co-stimulatory molecule expressed by activated T cells. It plays an important role in the activation and proliferation of T lymphocytes. Recently, some co-stimulatory molecules have been shown to direct leukocyte trafficking. Chemotaxis is essential for achieving an effective immune response. CCL20 is an important chemoattractant produced by activated T cells. In this study, using DO11.10 mice whose transgenic T cell receptor specifically recognizes ovalbumin, we demonstrate that ovalbumin induces OX40 expression in CD4+ lymphocytes. Further stimulation of OX40 by OX40 activating antibody up-regulates CCL20 production. Both NF-κB dependent and independent signaling pathways are implicated in the induction of CCL20 by OX40. Finally, we primed the DO11.10 splenocytes with or without OX40 activating antibody in the presence of ovalbumin. Intranasal administration of the cell lysates derived from the cells with OX40 stimulation results in more severe leukocyte infiltration in the lung of DO11.10 mice, which is substantially attenuated by CCL20 blocking antibody. Taken together, this study has shown that activation of OX40 induces CCL20 expression in the presence of antigen stimulation. Thus, our results broaden the role of OX40 in chemotaxis, and reveal a novel effect of co-stimulatory molecules in orchestrating both T cell up-regulation and migration.
PMCID: PMC2867600  PMID: 20400327
CCL20; CD4+ T cells; Co-stimulatory molecule; OX40; T cell co-stimulation
6.  CXCR4 But Not CXCR7 Is Mainly Implicated in Ocular Leukocyte Trafficking During Ovalbumin-Induced Acute Uveitis 
Experimental eye research  2009;89(4):522-531.
Uveitis is an inflammatory ocular disease characterized by the infiltration of T lymphocytes and other leukocytes into the eye. The recruitment of these inflammatory cells from systemic vasculature to ocular tissue is a well-coordinated multistep process including rolling, firm adhesion and transmigration. CXCL12 (SDF-1α) is an endothelial cell-derived cytokine interacting with CXCR4 and CXCR7, two chemokine receptors mainly expressed in T cells, neutrophils and monocytes. Recent studies have shown that CXCR4, CXCR7 and their ligand, CXCL12, are important for the regulation of leukocyte mobilization and trafficking. However, it is unclear whether these two chemokine receptors are implicated in the pathogenesis of uveitis. In this study, we used DO11.10 mice, whose CD4+ T cells are genetically engineered to react with ovalbumin (OVA), to investigate the role of CXCR4 and CXCR7 in an animal model of uveitis. Intravital microscopy revealed that intravitreal OVA challenge of DO11.10 mice caused the infiltration of both T cells and neutrophils. The invasion of these inflammatory cells coincided with the detection of transcriptional upregulation of CXCR4 and CXCR7 in the eye. In addition, both real time-PCR and immunohistochemistry revealed an enhanced expression of endothelial CXCL12. Furthermore, intraperitoneal injection of AMD3100 (a specific CXCR4 antagonist) significantly attenuated OVA-induced uveitis and CXCL12-mediated transwell migration. In contrast, intraperitoneal administration of CXCR7 neutralizing antibody did not significantly alter ocular infiltration of inflammatory cells caused by OVA challenge. Our data suggest that CXCR4 but not CXCR7 plays a critical role in antigen-induced ocular inflammation by facilitating leukocyte infiltration. This study not only enhances our knowledge of the immunopathological mechanism of uveitis but also provides a novel rationale to target CXCR4 as an anti-inflammatory strategy to treat uveitis.
PMCID: PMC2745349  PMID: 19524567
CXCL12; CXCR4; CXCR7; neutrophils; monocytes; ocular inflammation; T cells; uveitis
7.  Targeted suppression of heme oxygenase-1 by small interference RNAs inhibits the production of bilirubin in neonatal rat with hyperbilirubinemia 
BMC Molecular Biology  2009;10:77.
Excessive accumulation of bilirubin contributes to neonatal hyperbilirubinemia in rats. Heme oxygenase (HO) is one of the rate-limiting enzymes in catabolizing heme to bilirubin. In the present study, we investigated whether suppression of rat HO-1 (rHO-1) expression by small interference RNAs (siRNAs) reduces bilirubin levels in hyperbilirubinemic rats.
Four pairs of siRNA targeting rHO-1 mRNA were introduced into BRL cells and compared for their inhibitory effect on the expression of rHO-1 gene and production of rHO-1 protein. The siRNA exhibiting the most potent effect on HO-1 expression and activity was then administered intraperitoneally to 7 to 9-day-old rats with hyperbilirubinemia. The siRNA distributed mostly in the liver and spleen of neonatal rat. Serum bilirubin levels and hepatic HO-1 expression were further evaluated. Systemic treatment of siRNA targeting rHO-1 reduced hepatic HO-1 expression and decreased the serum bilirubin levels in a time- and dose-dependent manner, and siRNA decreased the indirect bilirubin levels more effectively than Sn-protoporphyrin (SnPP), an HO-1 inhibitor.
siRNA targeting rHO-l attenuates hepatic HO-1 expression and serum bilirubin levels. Thus this study provides a novel therapeutic rationale for the prevention and treatment of neonatal hyperbilirubinemia.
PMCID: PMC2726144  PMID: 19646271

Results 1-7 (7)