Bio

Honors & Awards


  • Spark Award, Stanford University (2014-2015)
  • Hugh McDevitt Prize, Stanford University (2014)
  • APDA Fellowship, American Parkinson's Disease Foundation (2014-2015)
  • Dean Fellowship, Stanford University (2014-2015)
  • AHA Fellowship, American Heart Association (2012-2013)
  • AHA Research Award, American Heart Association (2012)
  • Stanford Graduate Fellowship, Stanford University (2009-2012)

Professional Education


  • Doctor of Philosophy, Stanford University, IMMUN-PHD (2014)
  • Bachelor of Science, Stanford University, BIOL-BSH (2006)

Stanford Advisors


Research & Scholarship

Current Research and Scholarly Interests


Neuroscience
Immunology
Innate Immunity
Metabolism

Lab Affiliations


Publications

Journal Articles


  • Circadian Gene Bmal1 Regulates Diurnal Oscillations of Ly6C(hi) Inflammatory Monocytes SCIENCE Nguyen, K. D., Fentress, S. J., Qiu, Y., Yun, K., Cox, J. S., Chawla, A. 2013; 341 (6153): 1483-1488

    Abstract

    Circadian clocks have evolved to regulate physiologic and behavioral rhythms in anticipation of changes in the environment. Although the molecular clock is present in innate immune cells, its role in monocyte homeostasis remains unknown. Here, we report that Ly6C(hi) inflammatory monocytes exhibit diurnal variation, which controls their trafficking to sites of inflammation. This cyclic pattern of trafficking confers protection against Listeria monocytogenes and is regulated by the repressive activity of the circadian gene Bmal1. Accordingly, myeloid cell-specific deletion of Bmal1 induces expression of monocyte-attracting chemokines and disrupts rhythmic cycling of Ly6C(hi) monocytes, predisposing mice to development of pathologies associated with acute and chronic inflammation. These findings have unveiled a critical role for BMAL1 in controlling the diurnal rhythms in Ly6C(hi) monocyte numbers.

    View details for DOI 10.1126/science.1240636

    View details for Web of Science ID 000324894600042

    View details for PubMedID 23970558

  • Alternatively activated macrophages produce catecholamines to sustain adaptive thermogenesis NATURE Nguyen, K. D., Qiu, Y., Cui, X., Goh, Y. P., Mwangi, J., David, T., Mukundan, L., Brombacher, F., Locksley, R. M., Chawla, A. 2011; 480 (7375): 104-U272

    Abstract

    All homeotherms use thermogenesis to maintain their core body temperature, ensuring that cellular functions and physiological processes can continue in cold environments. In the prevailing model of thermogenesis, when the hypothalamus senses cold temperatures it triggers sympathetic discharge, resulting in the release of noradrenaline in brown adipose tissue and white adipose tissue. Acting via the ?(3)-adrenergic receptors, noradrenaline induces lipolysis in white adipocytes, whereas it stimulates the expression of thermogenic genes, such as PPAR-? coactivator 1a (Ppargc1a), uncoupling protein 1 (Ucp1) and acyl-CoA synthetase long-chain family member 1 (Acsl1), in brown adipocytes. However, the precise nature of all the cell types involved in this efferent loop is not well established. Here we report in mice an unexpected requirement for the interleukin-4 (IL-4)-stimulated program of alternative macrophage activation in adaptive thermogenesis. Exposure to cold temperature rapidly promoted alternative activation of adipose tissue macrophages, which secrete catecholamines to induce thermogenic gene expression in brown adipose tissue and lipolysis in white adipose tissue. Absence of alternatively activated macrophages impaired metabolic adaptations to cold, whereas administration of IL-4 increased thermogenic gene expression, fatty acid mobilization and energy expenditure, all in a macrophage-dependent manner. Thus, we have discovered a role for alternatively activated macrophages in the orchestration of an important mammalian stress response, the response to cold.

    View details for DOI 10.1038/nature10653

    View details for Web of Science ID 000298031900043

    View details for PubMedID 22101429

  • Macrophage-mediated inflammation in metabolic disease NATURE REVIEWS IMMUNOLOGY Chawla, A., Nguyen, K. D., Goh, Y. P. 2011; 11 (11): 738-749

    Abstract

    Metabolism and immunity are two fundamental systems of metazoans. The presence of immune cells, such as macrophages, in metabolic tissues suggests dynamic, ongoing crosstalk between these two regulatory systems. Here, we discuss how changes in the recruitment and activation of macrophages contribute to metabolic homeostasis. In particular, we focus our discussion on the pathogenic and protective functions of classically and alternatively activated macrophages, respectively, in experimental models of obesity and metabolic disease.

    View details for DOI 10.1038/nri3071

    View details for Web of Science ID 000296584700012

    View details for PubMedID 21984069

  • Adaptive Immunity and Antigen-Specific Activation in Obesity-Associated Insulin Resistance Mediators of Inflammation Ch'ng, M. H., Alonso, M. N., Barnes, S. E., Nguyen, K. D., Engleman, E. G. 2015
  • Generation of functional cortical neurons and astrocytes from human pluripotent stem cells in 3D cultures NATURE METHODS Pasca, A. M., Sloan, S. A., Clarke, L. E., Tian, Y., Makinson, C. D., Huber, N., Kim, C., Park, J., O'Rourke, N., Nguyen, K. D., Smith, S. J., Huguenard, J. R., Geschwind, D. H., Barres, B. A., Pasca, S. P. 2015
  • Serum amyloid A induces mitogenic signals in regulatory T cells via monocyte activation MOLECULAR IMMUNOLOGY Nguyen, K. D., Macaubas, C., Phi Truong, P., Wang, N., Hou, T., Yoon, T., Mellins, E. D. 2014; 59 (2): 172-179

    Abstract

    Serum amyloid A (SAA) has recently been identified by our group as a mitogen for regulatory T cells (Treg). However, the molecular mechanism by which SAA induces Treg proliferation is unknown. Here we provide evidence that IL-1β and IL-6 are directly involved in the SAA-mediated proliferation of Treg. By engaging its several cognate receptors, SAA induces IL-1β and IL-6 secretion by monocytes and drives them toward an HLA-DR(hi) HVEM(lo) phenotype resembling immature dendritic cells, which have been implicated in tolerance generation. This monocyte-derived cytokine milieu is required for Treg expansion, as inhibition of IL-1β and IL-6 abrogate the ability of SAA to induce Treg proliferation. Furthermore, both IL-1β and IL-6 are required for ERK1/2 and AKT signaling in proliferating Treg. Collectively, these results point to a novel mechanism, by which SAA initiates a monocyte-dependent process that drives mitogenic signals in Treg.

    View details for DOI 10.1016/j.molimm.2014.02.011

    View details for Web of Science ID 000334988800007

  • Eosinophils and type 2 cytokine signaling in macrophages orchestrate development of functional beige fat. Cell Qiu, Y., Nguyen, K. D., Odegaard, J. I., Cui, X., Tian, X., Locksley, R. M., Palmiter, R. D., Chawla, A. 2014; 157 (6): 1292-308

    Abstract

    Beige fat, which expresses the thermogenic protein UCP1, provides a defense against cold and obesity. Although a cold environment is the physiologic stimulus for inducing beige fat in mice and humans, the events that lead from the sensing of cold to the development of beige fat remain poorly understood. Here, we identify the efferent beige fat thermogenic circuit, consisting of eosinophils, type 2 cytokines interleukin (IL)-4/13, and alternatively activated macrophages. Genetic loss of eosinophils or IL-4/13 signaling impairs cold-induced biogenesis of beige fat. Mechanistically, macrophages recruited to cold-stressed subcutaneous white adipose tissue (scWAT) undergo alternative activation to induce tyrosine hydroxylase expression and catecholamine production, factors required for browning of scWAT. Conversely, administration of IL-4 to thermoneutral mice increases beige fat mass and thermogenic capacity to ameliorate pre-established obesity. Together, our findings have uncovered the efferent circuit controlling biogenesis of beige fat and provide support for its targeting to treat obesity.

    View details for DOI 10.1016/j.cell.2014.03.066

    View details for PubMedID 24906148

  • Signaling by IL-6 promotes alternative activation of macrophages to limit endotoxemia and obesity-associated resistance to insulin. Nature immunology Mauer, J., Chaurasia, B., Goldau, J., Vogt, M. C., Ruud, J., Nguyen, K. D., Theurich, S., Hausen, A. C., Schmitz, J., Brönneke, H. S., Estevez, E., Allen, T. L., Mesaros, A., Partridge, L., Febbraio, M. A., Chawla, A., Wunderlich, F. T., Brüning, J. C. 2014; 15 (5): 423-30

    Abstract

    Obesity and resistance to insulin are closely associated with the development of low-grade inflammation. Interleukin 6 (IL-6) is linked to obesity-associated inflammation; however, its role in this context remains controversial. Here we found that mice with an inactivated gene encoding the IL-6Rα chain of the receptor for IL-6 in myeloid cells (Il6ra(Δmyel) mice) developed exaggerated deterioration of glucose homeostasis during diet-induced obesity, due to enhanced resistance to insulin. Tissues targeted by insulin showed increased inflammation and a shift in macrophage polarization. IL-6 induced expression of the receptor for IL-4 and augmented the response to IL-4 in macrophages in a cell-autonomous manner. Il6ra(Δmyel) mice were resistant to IL-4-mediated alternative polarization of macrophages and exhibited enhanced susceptibility to lipopolysaccharide (LPS)-induced endotoxemia. Our results identify signaling via IL-6 as an important determinant of the alternative activation of macrophages and assign an unexpected homeostatic role to IL-6 in limiting inflammation.

    View details for DOI 10.1038/ni.2865

    View details for PubMedID 24681566

  • Eosinophils secrete IL-4 to facilitate liver regeneration PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Goh, Y. P., Henderson, N. C., Heredia, J. E., Eagle, A. R., Odegaard, J. I., Lehwald, N., Nguyen, K. D., Sheppard, D., Mukundan, L., Locksley, R. M., Chawla, A. 2013; 110 (24): 9914-9919

    Abstract

    The liver is a central organ for the synthesis and storage of nutrients, production of serum proteins and hormones, and breakdown of toxins and metabolites. Because the liver is susceptible to toxin- or pathogen-mediated injury, it maintains a remarkable capacity to regenerate by compensatory growth. Specifically, in response to injury, quiescent hepatocytes enter the cell cycle and undergo DNA replication to promote liver regrowth. Despite the elucidation of a number of regenerative factors, the mechanisms by which liver injury triggers hepatocyte proliferation are incompletely understood. We demonstrate here that eosinophils stimulate liver regeneration after partial hepatectomy and toxin-mediated injury. Liver injury results in rapid recruitment of eosinophils, which secrete IL-4 to promote the proliferation of quiescent hepatocytes. Surprisingly, signaling via the IL-4Rα in macrophages, which have been implicated in tissue repair, is dispensable for hepatocyte proliferation and liver regrowth after injury. Instead, IL-4 exerts its proliferative actions via IL-4Rα in hepatocytes. Our findings thus provide a unique mechanism by which eosinophil-derived IL-4 stimulates hepatocyte proliferation in regenerating liver.

    View details for DOI 10.1073/pnas.1304046110

    View details for Web of Science ID 000320930100072

  • Alternative activation in systemic juvenile idiopathic arthritis monocytes CLINICAL IMMUNOLOGY Macaubas, C., Nguyen, K. D., Peck, A., Buckingham, J., Deshpande, C., Wong, E., Alexander, H. C., Chang, S., Begovich, A., Sun, Y., Park, J. L., Pan, K., Lin, R., Lih, C., Augustine, E. M., Phillips, C., Hadjinicolaou, A. V., Lee, T., Mellins, E. D. 2012; 142 (3): 362-372

    Abstract

    Systemic juvenile idiopathic arthritis (SJIA) is a chronic autoinflammatory condition. The association with macrophage activation syndrome, and the therapeutic efficacy of inhibiting monocyte-derived cytokines, has implicated these cells in SJIA pathogenesis. To characterize the activation state (classical/M1 vs. alternative/M2) of SJIA monocytes, we immunophenotyped monocytes using several approaches. Monocyte transcripts were analyzed by microarray and quantitative PCR. Surface proteins were measured at the single cell level using flow cytometry. Cytokine production was evaluated by intracellular staining and ELISA. CD14(++)CD16(-) and CD14(+)CD16(+) monocyte subsets are activated in SJIA. A mixed M1/M2 activation phenotype is apparent at the single cell level, especially during flare. Consistent with an M2 phenotype, SJIA monocytes produce IL-1? after LPS exposure, but do not secrete it. Despite the inflammatory nature of active SJIA, circulating monocytes demonstrate significant anti-inflammatory features. The persistence of some of these phenotypes during clinically inactive disease argues that this state reflects compensated inflammation.

    View details for DOI 10.1016/j.clim.2011.12.008

    View details for Web of Science ID 000301036700016

    View details for PubMedID 22281427

  • Serum amyloid A overrides T-reg anergy via monocyte-dependent and T-reg-intrinsic, SOCS3-associated pathways BLOOD Nguyen, K. D., Macaubas, C., Nadeau, K. C., Phi Truong, T., Yoon, T., Lee, T., Park, J. L., Mellins, E. D. 2011; 117 (14): 3793-3798

    Abstract

    The acute phase protein serum amyloid A (SAA) has been well characterized as an indicator of inflammation. Nevertheless, its functions in pro versus anti-inflammatory processes remain obscure. Here we provide unexpected evidences that SAA induces the proliferation of the tolerogenic subset of regulatory T cells (T(reg)). Intriguingly, SAA reverses T(reg) anergy via its interaction with monocytes to activate distinct mitogenic pathways in T(reg) but not effector T cells. This selective responsiveness of T(reg) correlates with their diminished expression of SOCS3 and is antagonized by T(reg)-specific induction of this regulator of cytokine signaling. Collectively, these evidences suggest a novel anti-inflammatory role of SAA in the induction of a micro-environment that supports T(reg) expansion at sites of infection or tissue injury, likely to curb (auto)-inflammatory responses.

    View details for DOI 10.1182/blood-2010-11-318832

    View details for Web of Science ID 000289265500014

    View details for PubMedID 21325601

  • Plasma profiles in active systemic juvenile idiopathic arthritis: Biomarkers and biological implications PROTEOMICS Ling, X. B., Park, J. L., Carroll, T., Nguyen, K. D., Lau, K., Macaubas, C., Chen, E., Lee, T., Sandborg, C., Milojevic, D., Kanegaye, J. T., Gao, S., Burns, J., Schilling, J., Mellins, E. D. 2010; 10 (24): 4415-4430

    Abstract

    Systemic juvenile idiopathic arthritis (SJIA) is a chronic arthritis of children characterized by a combination of arthritis and systemic inflammation. There is usually non-specific laboratory evidence of inflammation at diagnosis but no diagnostic test. Normalized volumes from 89/889 2-D protein spots representing 26 proteins revealed a plasma pattern that distinguishes SJIA flare from quiescence. Highly discriminating spots derived from 15 proteins constitute a robust SJIA flare signature and show specificity for SJIA flare in comparison to active polyarticular juvenile idiopathic arthritis or acute febrile illness. We used 7 available ELISA assays, including one to the complex of S100A8/S100A9, to measure levels of 8 of the15 proteins. Validating our DIGE results, this ELISA panel correctly classified independent SJIA flare samples, and distinguished them from acute febrile illness. Notably, data using the panel suggest its ability to improve on erythrocyte sedimentation rate or C-reactive protein or S100A8/S100A9, either alone or in combination in SJIA F/Q discriminations. Our results also support the panel's potential clinical utility as a predictor of incipient flare (within 9?wk) in SJIA subjects with clinically inactive disease. Pathway analyses of the 15 proteins in the SJIA flare versus quiescence signature corroborate growing evidence for a key role for IL-1 at disease flare.

    View details for DOI 10.1002/pmic.201000298

    View details for Web of Science ID 000285882200008

    View details for PubMedID 21136595

  • Individual Variation in the Germline Ig Gene Repertoire Inferred from Variable Region Gene Rearrangements JOURNAL OF IMMUNOLOGY Boyd, S. D., Gaeta, B. A., Jackson, K. J., Fire, A. Z., Marshall, E. L., Merker, J. D., Maniar, J. M., Zhang, L. N., Sahaf, B., Jones, C. D., Simen, B. B., Hanczaruk, B., Nguyen, K. D., Nadeau, K. C., Egholm, M., Miklos, D. B., Zehnder, J. L., Collins, A. M. 2010; 184 (12): 6986-6992

    Abstract

    Individual variation in the Ig germline gene repertoire leads to individual differences in the combinatorial diversity of the Ab repertoire, but the study of such variation has been problematic. The application of high-throughput DNA sequencing to the study of rearranged Ig genes now makes this possible. The sequencing of thousands of VDJ rearrangements from an individual, either from genomic DNA or expressed mRNA, should allow their germline IGHV, IGHD, and IGHJ repertoires to be inferred. In addition, where previously mere glimpses of diversity could be gained from sequencing studies, new large data sets should allow the rearrangement frequency of different genes and alleles to be seen with clarity. We analyzed the DNA of 108,210 human IgH chain rearrangements from 12 individuals and determined their individual IGH genotypes. The number of reportedly functional IGHV genes and allelic variants ranged from 45 to 60, principally because of variable levels of gene heterozygosity, and included 14 previously unreported IGHV polymorphisms. New polymorphisms of the IGHD3-16 and IGHJ6 genes were also seen. At heterozygous loci, remarkably different rearrangement frequencies were seen for the various IGHV alleles, and these frequencies were consistent between individuals. The specific alleles that make up an individual's Ig genotype may therefore be critical in shaping the combinatorial repertoire. The extent of genotypic variation between individuals is highlighted by an individual with aplastic anemia who appears to lack six contiguous IGHD genes on both chromosomes. These deletions significantly alter the potential expressed IGH repertoire, and possibly immune function, in this individual.

    View details for DOI 10.4049/jimmunol.1000445

    View details for Web of Science ID 000278516700047

    View details for PubMedID 20495067

  • Distribution of circulating cells in systemic juvenile idiopathic arthritis across disease activity states CLINICAL IMMUNOLOGY Macaubas, C., Nguyen, K., Deshpande, C., Phillips, C., Peck, A., Lee, T., Park, J. L., Sandborg, C., Mellins, E. D. 2010; 134 (2): 206-216

    Abstract

    Juvenile idiopathic arthritis (JIA) encompasses a group of chronic childhood arthritides of unknown etiology. One subtype, systemic JIA (SJIA), is characterized by a combination of arthritis and systemic inflammation. Its systemic nature suggests that clues to SJIA pathogenesis may be found in examination of peripheral blood cells. To determine the immunophenotypic profiles of circulating mononuclear cells in SJIA patients with different degrees of disease activity, we studied PBMC from 31 SJIA patients, 20 polyarticular JIA patients (similar to adult rheumatoid arthritis), and 31 age-matched controls. During SJIA disease flare, blood monocyte numbers were increased, whereas levels of myeloid dendritic cells (DC) and gammadelta T cells were reduced. At both flare and quiescence, increased levels of CD14 and CD16 were found on SJIA monocytes. Levels of CD16-DC were elevated at SJIA quiescence compared both to healthy controls and to SJIA subjects with active disease. Overall, our findings suggest dysregulation of innate immunity in SJIA and raise the possibility that quiescence represents a state of compensated inflammation.

    View details for DOI 10.1016/j.clim.2009.09.010

    View details for Web of Science ID 000273701800013

    View details for PubMedID 19879195

  • TSLP directly impairs pulmonary Treg function: association with aberrant tolerogenic immunity in asthmatic airway. Allergy, asthma, and clinical immunology : official journal of the Canadian Society of Allergy and Clinical Immunology Nguyen, K. D., Vanichsarn, C., Nadeau, K. C. 2010; 6 (1): 4-?

    Abstract

    Even though thymic stromal lymphopoietin (TSLP) has been implicated in the development of allergic inflammation, its influence on immune tolerance mediated by regulatory T cells (Treg) have not been explored. We aimed to dissect the influence of TSLP on immunosuppressive activities of Treg and its potential consequences in human allergic asthma.In vitro culture system was utilized to study the effects of TSLP on human Treg. The functional competency of pulmonary Treg from a cohort of 15 allergic asthmatic, 15 healthy control, and 15 non-allergic asthmatic subjects was also evaluated by suppression assays and flow cytometric analysis.Activated pulmonary Treg expressed TSLP-R and responded to TSLP-mediated activation of STAT5. TSLP directly and selectively impaired IL-10 production of Treg and inhibited their suppressive activity. In human allergic asthma, pulmonary Treg exhibited a significant decrease in suppressive activity and IL-10 production compared to healthy control and non-allergic asthmatic counterparts. These functional alterations were associated with elevated TSLP expression in bronchoalveolar lavage fluid (BAL) of allergic asthmatic subjects. Furthermore, allergic asthmatic BAL could suppress IL-10 production by healthy control pulmonary Treg in a TSLP-dependent manner.These results provide the first evidences for a direct role of TSLP in the regulation of suppressive activities of Treg. TSLP mediated inhibition of Treg function might present a novel pathologic mechanism to dampen tolerogenic immune responses in inflamed asthmatic airway.

    View details for DOI 10.1186/1710-1492-6-4

    View details for PubMedID 20230634

  • Measurement and Clinical Monitoring of Human Lymphocyte Clonality by Massively Parallel V-D-J Pyrosequencing SCIENCE TRANSLATIONAL MEDICINE Boyd, S. D., Marshall, E. L., Merker, J. D., Maniar, J. M., Zhang, L. N., Sahaf, B., Jones, C. D., Simen, B. B., Hanczaruk, B., Nguyen, K. D., Nadeau, K. C., Egholm, M., Miklos, D. B., Zehnder, J. L., Fire, A. Z. 2009; 1 (12)

    Abstract

    The complex repertoire of immune receptors generated by B and T cells enables recognition of diverse threats to the host organism. In this work, we show that massively parallel DNA sequencing of rearranged immune receptor loci can provide direct detection and tracking of immune diversity and expanded clonal lymphocyte populations in physiological and pathological contexts. DNA was isolated from blood and tissue samples, a series of redundant primers was used to amplify diverse DNA rearrangements, and the resulting mixtures of barcoded amplicons were sequenced using long-read ultra deep sequencing. Individual DNA molecules were then characterized on the basis of DNA segments that had been joined to make a functional (or nonfunctional) immune effector. Current experimental designs can accommodate up to 150 samples in a single sequence run, with the depth of sequencing sufficient to identify stable and dynamic aspects of the immune repertoire in both normal and diseased circumstances. These data provide a high-resolution picture of immune spectra in normal individuals and in patients with hematological malignancies, illuminating, in the latter case, both the initial behavior of clonal tumor populations and the later suppression or re-emergence of such populations after treatment.

    View details for DOI 10.1126/scitranslmed.3000540

    View details for Web of Science ID 000277263200001

    View details for PubMedID 20161664

  • Oligoarticular and polyarticular JIA: epidemiology and pathogenesis NATURE REVIEWS RHEUMATOLOGY Macaubas, C., Nguyen, K., Milojevic, D., Park, J. L., Mellins, E. D. 2009; 5 (11): 616-626

    Abstract

    Juvenile idiopathic arthritis (JIA) refers to a group of chronic childhood arthropathies of unknown etiology, currently classified into subtypes primarily on the basis of clinical features. Research has focused on the hypothesis that these subtypes arise through distinct etiologic pathways. In this Review, we discuss four subtypes of JIA: persistent oligoarticular, extended oligoarticular, rheumatoid-factor-positive polyarticular and rheumatoid-factor-negative polyarticular. These subtypes differ in prevalence between ethnic groups and are associated with different HLA alleles. Non-HLA genetic risk factors have also been identified, some of which reveal further molecular differences between these subtypes, while others suggest mechanistic overlap. Investigations of immunophenotypes also provide insights into subtype differences: adaptive immunity seems to have a prominent role in both polyarticular and oligoarticular JIA, and the more-limited arthritis observed in persistent oligoarticular JIA as compared with extended oligoarticular JIA may reflect more-potent immunoregulatory T-cell activity in the former. Tumor necrosis factor seems to be a key mediator of both polyarticular and oligoarticular JIA, especially in the extended oligoarticular subtype, although elevated levels of other cytokines are also observed. Limited data on monocytes, dendritic cells, B cells, natural killer T cells and neutrophils suggest that the contributions of these cells differ across subtypes of JIA. Within each subtype, however, common pathways seem to drive joint damage.

    View details for DOI 10.1038/nrrheum.2009.209

    View details for Web of Science ID 000271246900007

    View details for PubMedID 19806151

  • Impaired IL-10-dependent Induction of Tolerogenic Dendritic Cells by CD4(+)CD25(hi)CD127(lo/-) Natural Regulatory T Cells in Human Allergic Asthma AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE Nguyen, K. D., Vanichsarn, C., Nadeau, K. C. 2009; 180 (9): 823-833

    Abstract

    Tolerogenic dendritic cells and natural regulatory T cells have been implicated in the process of infectious tolerance in human allergic asthma. However, the significance of the influence of natural regulatory T cells on tolerogenic dendritic cells in the disease has not been investigated.We aimed to characterize the mechanism of induction of the tolerogenic phenotype in circulating blood dendritic cells by allergic asthmatic natural regulatory T cells.The study was performed in a cohort of 21 subjects with allergic asthma, 21 healthy control subjects, and 21 subjects with nonallergic asthma. We cultured blood dendritic cells with natural regulatory T cells to study the induction of tolerogenic dendritic cells. Flow cytometry and proliferation assays were employed to analyze phenotype and function of dendritic cells as well as IL-10 production from natural regulatory T cells.Dendritic cells cultured with natural regulatory T cells up-regulated IL-10, down-regulated costimulatory molecules, and stimulated the proliferation of CD4(+)CD25(-) effector T cells less potently. Allergic asthmatic natural regulatory T cells were significantly less efficient in inducing this tolerogenic phenotype of dendritic cells compared with healthy control and nonallergic asthmatic counterparts. Furthermore, this defective function of natural regulatory T cells was associated with their decreased IL-10 expression, disease severity, and could be reversed by oral corticosteroid therapy.These results provided the first evidences of impaired induction of tolerogenic dendritic cells mediated by natural regulatory T cells in human allergic asthma.

    View details for DOI 10.1164/rccm.200905-0761OC

    View details for Web of Science ID 000271215500006

    View details for PubMedID 19679691

  • PPAR-delta senses and orchestrates clearance of apoptotic cells to promote tolerance NATURE MEDICINE Mukundan, L., Odegaard, J. I., Morel, C. R., Heredia, J. E., Mwangi, J. W., Ricardo-Gonzalez, R. R., Goh, Y. P., Eagle, A. R., Dunn, S. E., Awakuni, J. U., Nguyen, K. D., Steinman, L., Michie, S. A., Chawla, A. 2009; 15 (11): 1266-U59

    Abstract

    Macrophages rapidly engulf apoptotic cells to limit the release of noxious cellular contents and to restrict autoimmune responses against self antigens. Although factors participating in recognition and engulfment of apoptotic cells have been identified, the transcriptional basis for the sensing and the silent disposal of apoptotic cells is unknown. Here we show that peroxisome proliferator-activated receptor-delta (PPAR-delta) is induced when macrophages engulf apoptotic cells and functions as a transcriptional sensor of dying cells. Genetic deletion of PPAR-delta decreases expression of opsonins such as complement component-1qb (C1qb), resulting in impairment of apoptotic cell clearance and reduction in anti-inflammatory cytokine production. This increases autoantibody production and predisposes global and macrophage-specific Ppard(-/-) mice to autoimmune kidney disease, a phenotype resembling the human disease systemic lupus erythematosus. Thus, PPAR-delta has a pivotal role in orchestrating the timely disposal of apoptotic cells by macrophages, ensuring that tolerance to self is maintained.

    View details for DOI 10.1038/nm.2048

    View details for Web of Science ID 000271543700014

    View details for PubMedID 19838202

  • Selective deregulation in chemokine signaling pathways of CD4(+)CD25(hi)CD127(lo/-) regulatory T cells in human allergic asthma JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY Nguyen, K. D., Vanichsarn, C., Fohner, A., Nadeau, K. C. 2009; 123 (4): 933-939

    Abstract

    CD4+CD25(hi)CD127(lo)/(-) regulatory T cells have been suggested to be critical regulators of inflammatory processes in allergic asthma. Recent studies reported a selective decrease in the frequency of regulatory T cells in the bronchoalveolar lavage fluid of allergic asthmatic (AA) subjects, prompting the possibility of defective recruitment of these cells to the airway in response to chemokines produced during asthmatic inflammation.This study aimed to characterize the chemotactic profile of circulating regulatory T cells in AA subjects in response to chemokines abundantly produced in airway inflammation, such as CCL1, CCL17, and CCL22.The study was performed in a cohort of 26 AA, 16 healthy control, and 16 non-AA subjects. We used chemotaxis assays to evaluate cell migration, flow cytometry to examine chemokine receptor expression, and phospho-ELISA to study consequent signaling pathways in regulatory T cells.Regulatory T cells, but not CD4+CD25(-)T cells, from AA subjects showed decreased chemotactic responses, specifically to CCL1, in comparison with their healthy control and non-AA counterparts. Decreased CCL1-mediated chemotaxis in AA regulatory T cells was associated with decreased phosphorylation of protein kinase B (AKT), a protein involved in chemokine intracellular signaling. Furthermore, the decreased chemotactic response to CCL1 in AA regulatory T cells significantly correlated with asthma severity and decreased pulmonary function in AA subjects.These results provide the first evidence of dysfunction in the chemokine signaling pathway in AA regulatory T cells.

    View details for DOI 10.1016/j.jaci.2008.11.037

    View details for Web of Science ID 000265058600023

    View details for PubMedID 19152963

  • XCL1 enhances regulatory activities of CD4(+)CD25(high)CD127(low/-) T cells in human allergic asthma JOURNAL OF IMMUNOLOGY Nguyen, K. D., Fohner, A., Booker, J. D., Dong, C., Krensky, A. M., Nadeau, K. C. 2008; 181 (8): 5386-5395

    Abstract

    Chemokine-mediated recruitment of regulatory cell subsets to the airway during inflammation and enhancement of their activities are potential strategies for therapeutic development in allergic asthma (AA). In this study, we aim to explore the role of XCL1, a chemokine associated with immune suppression and allergy, on CD4(+)CD25(high)CD127(low/-) regulatory T cell (Treg) function in AA. Flow cytometry and PCR analysis showed a reduction in XCL1 and XCR1 expression in AA Treg compared with healthy control and nonallergic asthmatic counterparts. This reduction in XCL1 expression was associated with the suboptimal regulatory function of Treg in AA. Interestingly, incubation with recombinant human XCL1 significantly increased Treg-mediated suppression and cytotoxicity by up-regulating expression of XCL1 and chief effector molecules of Treg function. Altogether, these results suggest an association between dysregulated XCL1 expression and reduced Treg activities in AA, as well as a potential role of XCL1 in reversing defective Treg function in the disease.

    View details for Web of Science ID 000260025300030

    View details for PubMedID 18832695

  • Increased cytotoxicity of CD4(+) invariant NKT cells against CD4(+)CD25(hi)CD127(lo/-) regulatory T cells in allergic asthma EUROPEAN JOURNAL OF IMMUNOLOGY Nguyen, K. D., Vanichsarn, C., Nadeau, K. C. 2008; 38 (7): 2034-2045

    Abstract

    CD4+CD25(hi)CD127(lo/-) regulatory T cells (Treg) have been implicated in the resolution of asthma-associated inflammation while the opposite role of CD4+ invariant NKT (iNKT) cells has been the subject of recent investigations. Studies here focused on mechanisms of interaction between CD4+ iNKT cells and Treg to further explore their roles in allergic asthma (AA). Flow cytometry analysis revealed a significant increase in the expression of the natural cytotoxicity receptors NKp30 and NKp46 by CD4+ iNKT cells in AA subjects compared to healthy controls (HC) and non-allergic asthmatics (NA). Subsequent intracellular staining showed that CD4+ iNKT cells also expressed higher levels of granzyme B and perforin in AA than HC. In in vitro killing assays, AA CD4+ iNKT cells selectively killed autologous Treg, but not CD4+CD25- T cells, more potently than HC and NA counterparts. This increased cytotoxicity positively correlated with asthma severity and granzyme B/perforin expression of CD4+ iNKT cells. Furthermore, it could be abrogated by either inhibition of the granzyme B-/perforin-dependent cell death pathway or oral corticosteroid administration. Altogether, these findings suggest that increased cytotoxicity of CD4+ iNKT cells against Treg might contribute to dysfunctional cellular interactions in AA.

    View details for DOI 10.1002/eji.200738082

    View details for Web of Science ID 000257826300027

    View details for PubMedID 18581330

  • Regulatory T cells and their role in rheumatic diseases: a potential target for novel therapeutic development. Pediatric rheumatology online journal Milojevic, D., Nguyen, K. D., Wara, D., Mellins, E. D. 2008; 6: 20-?

    Abstract

    Regulatory T cells have an important role in limiting immune reactions and are essential regulators of self-tolerance. Among them, CD4+CD25high regulatory T cells are the best-described subset. In this article, we summarize current knowledge on the phenotype, function, and development of CD4+CD25high regulatory T cells. We also review the literature on the role of these T cells in rheumatic diseases and discuss the potential for their use in immunotherapy.

    View details for DOI 10.1186/1546-0096-6-20

    View details for PubMedID 19046457

  • Altered phosphorylated signal transducer and activator of transcription profile of CD4(+)CD161(+) T cells in asthma: Modulation by allergic status and oral corticosteroids JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY Gernez, Y., Tirouvanziam, R., Nguyen, K. D., Herzenberg, L. A., Krensky, A. M., Nadeau, K. C. 2007; 120 (6): 1441-1448

    Abstract

    Asthma is a complex immunologic disorder linked to altered cytokine signaling.We tested whether asthmatic patients showed any change in cytokine-dependent signal transducer and activator of transcription (STAT) levels, focusing on the central/effector-memory CD4(+)CD161(+) subset, which represents 15% to 25% of circulating T cells.We quantified intracellular levels of active phosphorylated STAT (phospho-STAT) 1, 3, 5, and 6 by means of flow cytometry, without any activation or expansion.Baseline phospho-STAT1 and phospho-STAT6 levels were increased in CD4(+)CD161(+) T cells from asthmatic patients compared with those from healthy control subjects (by 10- and 8-fold, respectively). This asthma-associated alteration was both subset specific because no change was seen in CD4(+)CD161(-)CD25(+) (regulatory T cells) and CD4(+)CD161(-)CD25(-) subsets and isoform specific because phospho-STAT5 and phospho-STAT3 levels were unchanged. Among asthmatic patients, phospho-STAT1 and phospho-STAT6 levels correlated negatively with each other, suggesting antagonistic regulation. Oral corticosteroid (OCS) treatment significantly decreased phospho-STAT6 and IL-4 levels but not phospho-STAT1 levels. Disease parameters showing significant correlations with phospho-STAT1, phospho-STAT6, or both included age at onset, plasma IgE levels, and levels of the T(H)2 cytokines IL-4 and IL-10 and the T(H)1 cytokine IL-2. Overall, combined phospho-STAT1 and phospho-STAT6 measurements showed excellent predictive value for identifying (1) asthmatic patients versus healthy control subjects, (2) allergic versus nonallergic asthmatic patients, and (3) asthmatic patients taking versus those not taking OCSs.Baseline changes in phospho-STAT1 and phospho-STAT6 levels in blood CD4(+)CD161(+) T cells identify asthmatic patients and mirror their allergic status and response to OCSs.These results confirm the pathologic importance of activated STAT1 and STAT6 in asthma and suggest their potential use as clinical biomarkers.

    View details for DOI 10.1016/j.jaci.2007.08.012

    View details for Web of Science ID 000251653800029

    View details for PubMedID 17919711

Conference Proceedings


  • Lymphotactin improves treg function in asthmatics via the STAT5 pathway Fohner, A., Nguyen, K., Krensky, A. M., Nadeau, K. C. ACADEMIC PRESS INC ELSEVIER SCIENCE. 2007: S77-S77
  • Distinct molecular and cellular aspects of systemic juvenile idiopathic arthritis (SJIA) and polyarticular (PolyJIA) Macaubas, C., Nguyen, K., Pan, K., Lee, T., Deshpande, C., Sandborg, C., Cohen, S., Mellins, E. ACADEMIC PRESS INC ELSEVIER SCIENCE. 2007: S94-S95

Stanford Medicine Resources: