Chronic intestinal nematode infection induces Stat6-independent interleukin-5 production and causes eosinophilic inflammatory responses in mice

The role of Stat6 (signal transducers and activators of transcription) in the recruitment and activation of eosinophils has been studied in detail in asthma and other allergic diseases. In this study, we demonstrated that eosinophil responses occur in a Stat6-independent manner in mice infected with the intestinal nematode, Nippostrongylus brasiliensis. Stat6-deficient (Stat6(-/-)) mice cannot expel N. brasiliensis and establish chronic infections. Prominent blood and intestinal eosinophilia were induced after day 14 postinfection (p.i.) and maintained at this level in Stat6(-/-) mice, whereas in wild-type mice eosinophil responses reached a peak on day 10 p.i. and declined thereafter. The introduction of a secondary infection of N. brasiliensis into wild-type mice induced rapid and exaggerated eosinophilia, whereas secondary infection in Stat6(-/-) mice resulted in almost the same eosinophil responses as those of the primary infection, suggesting a lack of memory responses. Blood eosinophilia was also induced in Stat6(-/-) mice implanted with N. brasiliensis in the small intestine, suggesting that intestinal exposure to parasitic antigen is sufficient to induce eosinophil responses. Furthermore, this prominent eosinophil response of Stat6(-/-) mice after day 14 was closely associated with an increase of interleukin (IL)-5 production in serum and intestine. Neither IL-4 nor eotaxin were significantly induced in Stat6(-/-) mice after infection with N. brasiliensis. We also found that mRNA for IL-5, GATA-3 and eosinophil peroxidase (EPO) are induced in the intestine of Stat6(-/-) mice on day 14 p.i. Taken together, these results provide evidence for Stat6-independent IL-5 production and subsequent eosinophil responses after chronic infection with N. brasiliensis.

Th1 and Th2 cytokine production is suppressed at the level of transcriptional regulation in Kawasaki disease

To clarify the functional state of T cells in Kawasaki disease, we analysed mRNA expression levels of Th1/Th2 cytokines (IFN-gamma and IL-4) along with Th1/Th2-inducing transcription factors, T-bet and GATA-3, which play pivotal roles in the development of Th1 and Th2 cells, respectively. By real-time PCR, IFN-gamma mRNA levels in peripheral blood mononuclear cells (PBMNC) were significantly decreased in Kawasaki disease patients compared with those with measles, and tended to be lower than those in healthy controls. T-bet mRNA levels were significantly decreased in patients with Kawasaki disease compared with healthy controls. In addition, IL-4 and GATA-3 mRNA levels were significantly decreased in Kawasaki disease compared with healthy controls. Regulatory cytokine mRNA levels (TGF-beta and IL-10) were also decreased in Kawasaki disease. The mRNA levels of IFN-gamma showed a significant positive correlation with those of T-bet in Kawasaki disease. These results suggest that the suppressed function of Th1 and Th2, associated with the suppression of both T-bet and GATA-3 gene expression, may be one of the immunological characteristics of Kawasaki disease.

Long-range intrachromosomal interactions in the T helper type 2 cytokine locus

The T helper type 2 (T(H)2) locus control region is important in the regulation of the genes encoding the cytokines interleukins 4, 5 and 13. Using the chromosome conformation capture technique, we found that in T cells, natural killer cells, B cells and fibroblasts, the promoters for the genes encoding T(H)2 cytokines are located in close spatial proximity, forming an initial chromatin core configuration. In CD4(+) T cells and natural killer cells, but not B cells and fibroblasts, the T(H)2 locus control region participates in this configuration. The transcription factors GATA3 and STAT6 are essential for the establishment and/or maintenance of these interactions. Intrachromosomal interactions in the T(H)2 cytokine locus may form the basis for the coordinated transcriptional regulation of cytokine-encoding genes by the T(H)2 locus control region.

[Preventive effect of anterior chamber associated immune deviation on endotoxin-induced uveitis]

OBJECTIVE

To determine the effect of anterior chamber associated immune deviation (ACAID) on endotoxin-induced uveitis (EIU) and the possible mechanism.

METHODS

ACAID animal model was induced by injection of 5 microl IRBP (10 microg/microl) into the anterior chamber (AC) of Spar-Dawley (SD) rats. Then 200 microg LPS was injected into hind footpads at different time points after AC inoculation. The animals were randomly divided into 3 groups: positive control (LPS injection only), 3 d group (LPS injection 3 days after IRBP inoculation), 7 d group (LPS injection 7 days after IRBP inoculation). Delayed type hypersensitivity (DTH) was examined to determine the development of ACAID. Then the serum level of IL-10 was evaluated by ELISA, and GATA-3 expression at the different time points after IRBP injection was assayed by reverse transcription polymerase chain reaction (RT-PCR) and Western blot on mRNA and protein level respectively. The ocular inflammation was observed clinically; at the same time, the eye was extirpated and histological examination was performed.

RESULTS

In control and 3 d groups, significant DTH reaction was induced, but the serum level of IL-10 could not be detected and GATA-3 expression was not increased. While in 7 d group, the DTH reaction could not be induced, and IL-10 and GATA-3 expression increased significantly at both the mRNA and protein levels. The clinical manifestation was significantly alleviated in the 7 d group; Histological examination displayed that the inflammatory cells were significantly reduced in iris/ciliary body, anterior and posterior chambers, vitreous body and retina of the rats in 7 d group.

CONCLUSION

The development of ACAID can reduce the ocular inflammation induced by LPS, that is related to the increase of GATA-3 and IL-10 expression.

Transgenic overexpression of GATA-3 in T lymphocytes improves autoimmune glomerulonephritis in mice with a BXSB/MpJ-Yaa genetic background

A T helper 1 (Th1)/Th2 imbalance is thought to contribute to the pathogenesis of autoimmune diseases. The differentiation of T cells into Th1 or Th2 subtypes is under the regulation of several transcription factors. Among these, transcription factor GATA-3 is thought to play an indispensable role in the development of T cells and the differentiation of Th2 cells. To examine how a Th1/Th2 imbalance affects the development of autoimmune disease, GATA-3 was overexpressed in the T lymphocytes of C57BL/6 x BXSB/MpJ-Yaa F(1) (Yaa) mice. Yaa mice developed autoimmune nephritis similarly to BXSB/MpJ-Yaa mice, which are commonly used as a model for Th1-dominant murine lupus. GATA-3 overexpression in T cells improved the 50% mortality incidence time for GATA-3-transgenic Yaa mice (41.6 wk), compared with Yaa mice (30.9 wk), and reduced proteinuria, serum creatinine levels, and the severity of glomerulonephritis in GATA-3-transgenic Yaa mice. GATA-3 overexpression in Yaa mice led to simultaneously elevated Th2 Ig (IgG1) and decreased Th1 Ig (IgG2a and IgG3) production and serum IFN-gamma levels. Although IL-4 production remained unchanged, intracellular cytokine analyses demonstrated that IL-5 was induced and IFN-gamma was suppressed in stimulated T cells from the GATA-3-transgenic Yaa mice. These results indicated that abundant GATA-3 was unable to stimulate complete differentiation of Th2 cells but did counteract the dominance of Th1 cells and alleviated the disease severity in Yaa mice. These data suggest that transcriptional regulation therapy may have potential as an effective strategy for treating autoimmune glomerulonephritis.

Immunologic immaturity, but high IL-4 productivity, of murine neonatal thymic CD4 single-positive T cells in the last stage of maturation

To determine the levels of maturation and differentiation of murine CD4 single-positive (SP) T cells, we compared the secondary responses of staphylococcal enterotoxin A (SEA)-induced neonatal thymic, adult thymic and adult splenic CD4 SP T cell blasts prepared from whole or heat-stable antigen(low) CD4 SP T cells. Proliferative responses upon re-stimulation with SEA were strong in adult splenic CD4 SP T cell blasts, but quite weak in neonatal thymic and adult thymic CD4 SP T cell blasts. SEA-induced IL-2 production was weaker in neonatal thymic blasts than in the adult splenic CD4 SP T cell blasts. In contrast, SEA-induced IL-4 production was high in neonatal thymic CD4 SP T cell blasts, and low in adult splenic and thymic CD4 SP T cell blasts. Expression of GATA-3, that directs production of IL-4 in T cells, examined at protein and mRNA levels, was higher in neonatal thymic cells than in adult thymic and splenic cells. These results suggest that neonatal and adult thymic CD4 SP T cells in the final stage of maturation are relatively immature compared with adult splenic CD4 SP T cells. The cytokine production profile of neonatal thymic CD4 SP T cells suggests that they are inclined towards a T(h)2 response.

GATA-3 in human T cell helper type 2 development

The delineation of the in vivo role of GATA-3 in human T cell differentiation is a critical step in the understanding of molecular mechanisms directing human immune responses. We examined T cell differentiation and T cell–mediated effector functions in individuals lacking one functional GATA-3 allele. CD4 T cells from GATA-3^+/− individuals expressed significantly reduced levels of GATA-3, associated with markedly decreased T helper cell (Th)2 frequencies in vivo and in vitro. Moreover, Th2 cell–mediated effector functions, as assessed by serum levels of Th2-dependent immunoglobulins (Igs; IgG4, IgE), were dramatically decreased, whereas the Th1-dependent IgG1 was elevated compared with GATA-3^+/+ controls. Concordant with these data, silencing of GATA-3 in GATA-3^+/+ CD4 T cells with small interfering RNA significantly reduced Th2 cell differentiation. Moreover, GATA-3 mRNA levels increased under Th2-inducing conditions and decreased under Th1-inducing conditions. Taken together, the data strongly suggest that GATA-3 is an important transcription factor in regulating human Th2 cell differentiation in vivo.

IL-4-induced GATA-3 expression is a time-restricted instruction switch for Th2 cell differentiation

An initial activation signal via the TCR in a restricted cytokine environment is critical for the onset of Th cell development. Cytokines regulate the expression of key transcriptional factors, T-bet and GATA-3, which instruct the direction of Th1 and Th2 differentiation, through changes in chromatin conformation. In this study, we investigated the kinetics of IL-4-mediated signaling in a transgenic mouse, expressing human IL-4R on a mouse IL-4alphaR-deficient background. These experiments, allowing induction with human IL-4 at defined times, demonstrated that an IL-4 signal was required at the early stage of TCR-mediated T cell activation for lineage commitment to Th2, along with structural changes in chromatin, which take place in the conserved noncoding sequence-1 and -2 within the IL-4 locus. At later times, however, IL-4 failed to promote efficient Th2 differentiation and decondensation of chromatin, even though GATA-3 was clearly induced in the nuclei by IL-4 stimulation. Moreover, IL-4-mediated Th2 instruction was independent from cell division mediated by initial TCR stimulation. The role of IL-4 signaling may have a time restriction during Th2 differentiation. In late stages of initial T cell activation, the chromatin structure of the IL-4 locus retains condensation state. These results demonstrate that IL-4-induced GATA-3 expression is time-restriction switch for Th2 differentiation.

Evolutionary origins of lymphocytes: ensembles of T cell and B cell transcriptional regulators in a cartilaginous fish

The evolutionary origins of lymphocytes can be traced by phylogenetic comparisons of key features. Homologs of rearranging TCR and Ig (B cell receptor) genes are present in jawed vertebrates, but have not been identified in other animal groups. In contrast, most of the transcription factors that are essential for the development of mammalian T and B lymphocytes belong to multigene families that are represented by members in the majority of the metazoans, providing a potential bridge to prevertebrate ancestral roles. This work investigates the structure and regulation of homologs of specific transcription factors known to regulate mammalian T and B cell development in a representative of the earliest diverging jawed vertebrates, the clearnose skate (Raja eglanteria). Skate orthologs of mammalian GATA-3, GATA-1, EBF-1, Pax-5, Pax-6, Runx2, and Runx3 have been characterized. GATA-3, Pax-5, Runx3, EBF-1, Spi-C, and most members of the Ikaros family are shown throughout ontogeny to be 1) coregulated with TCR or Ig expression, and 2) coexpressed with each other in combinations that for the most part correspond to known mouse T and B cell patterns, supporting conservation of function. These results indicate that multiple components of the gene regulatory networks that operate in mammalian T cell and B cell development were present in the common ancestor of the mammals and the cartilaginous fish. However, certain factors relevant to the B lineage differ in their tissue-specific expression patterns from their mouse counterparts, suggesting expanded or divergent B lineage characteristics or tissue specificity in these animals.

Transcriptional control networks of cell differentiation: insights from helper T lymphocytes

Coordinated programs of gene expression during cell differentiation can be controlled by master transcription factors. The differentiation of helper T (Th) lymphocytes during the immune response has been shown to occur along alternative pathways designated as Th1 and Th2. Induction of the Th1 and Th2 pathways is associated with the conversely regulated expression of the master factors T-bet and GATA-3, respectively. Both autoactivation and inhibition of GATA-3 play a crucial role in this process. We develop mathematical models of the underlying regulatory networks to provide a framework for the analysis of experimental data. Modeling concepts for gene expression dynamics are introduced, and paradigms for the behavior of gene-regulatory networks are reviewed. A mechanistic model for the regulation of GATA-3 in Th cells is developed that accounts for autoactivation and regulation by external differentiation signals. This system works as a bistable switch that enables the triggering of a differentiation program by transient inductive signals. GATA-3 inhibitors (such as FOG-1 and ROG) modulate GATA-3 expression by yet unidentified mechanisms. Three potential modes of inhibition, sequestration by a binding protein, repression of basal transcription, and repression of autoactivation, are predicted to have distinct, and strongly concentration-dependent, regulatory effects on GATA-3 dynamics. Based on these results, we develop a model for the cross-regulation of the alternative Th1 and Th2 differentiation programs which are governed by the dynamics of T-bet and GATA-3, respectively. The steady states of this model correlate with naïve, Th1-polarized, and Th2-polarized phenotypes. Our analysis makes predictions on the stability of the Th1 and Th2 programs and raises questions on the relation between transcription factor regulation and epigenetic determination in cell differentiation.

Essential role of Gata transcription factors in sympathetic neuron development

Sympathetic neurons are specified during their development from neural crest precursors by a network of crossregulatory transcription factors, which includes Mash1, Phox2b, Hand2 and Phox2a. Here, we have studied the function of Gata2 and Gata3 zinc-finger transcription factors in autonomic neuron development. In the chick, Gata2 but not Gata3 is expressed in developing sympathetic precursor cells. Gata2 expression starts after Mash1, Phox2b, Hand2 and Phox2a expression, but before the onset of the noradrenergic marker genes Th and Dbh, and is maintained throughout development. Gata2 expression is affected in the chick embryo by Bmp gain- and loss-of-function experiments, and by overexpression of Phox2b, Phox2a, Hand2 and Mash1. Together with the lack of Gata2/3 expression in Phox2b knockout mice, these results characterize Gata2 as member of the Bmp-induced cluster of transcription factors. Loss-of-function experiments resulted in a strong reduction in the size of the sympathetic chain and in decreased Th expression. Ectopic expression of Gata2 in chick neural crest precursors elicited the generation of neurons with a non-autonomic, Th-negative phenotype. This implies a function for Gata factors in autonomic neuron differentiation, which, however, depends on co-regulators present in the sympathetic lineage. The present data establish Gata2 and Gata3 in the chick and mouse, respectively, as essential members of the transcription factor network controlling sympathetic neuron development.

Endothelin-A receptor-dependent and -independent signaling pathways in establishing mandibular identity

The lower jaw skeleton is derived from cephalic neural crest (CNC) cells that reside in the mandibular region of the first pharyngeal arch. Endothelin-A receptor (Ednra) signaling in crest cells is crucial for their development, as Ednra(-/-) mice are born with severe craniofacial defects resulting in neonatal lethality. In this study, we undertook a more detailed analysis of mandibular arch development in Ednra(-/-) embryos to better understand the cellular and molecular basis for these defects. We show that most lower jaw structures in Ednra(-/-) embryos undergo a homeotic transformation into maxillary-like structures similar to those observed in Dlx5/Dlx6(-/-) embryos, though lower incisors are still present in both mutant embryos. These structural changes are preceded by aberrant expansion of proximal first arch gene expression into the distal arch, in addition to the previously described loss of a Dlx6/Hand2 expression network. However, a small distal Hand2 expression domain remains. Although this distal expression is not dependent on either Ednra or Dlx5/Dlx6 function, it may require one or more GATA factors. Using fate analysis, we show that these distal Hand2-positive cells probably contribute to lower incisor formation. Together, our results suggest that the establishment of a 'mandibular identity' during lower jaw development requires both Ednra-dependent and -independent signaling pathways.

Retinal selectivity of gene expression in rat retinal versus brain capillary endothelial cell lines by differential display analysis

PURPOSE

The retina is a neural tissue especially differentiated for vision and, thus, the inner blood-retinal barrier (inner BRB) specific molecules may play an essential role in maintaining neural functions in the retina. The purpose of the present study was to identify selectively expressed genes at the inner blood-retinal barrier compared with the blood-brain barrier (BBB).

METHODS

A comparison of expressed genes between conditionally immortalized rat retinal (TR-iBRB) cell lines and brain capillary endothelial (TR-BBB) cell lines was performed using mRNA differential display analysis and quantitative real time PCR analysis. The rat M-cadherin gene was cloned by performing 5' RACE, and its protein expression was detected by immunoblot analysis.

RESULTS

Eight clones were identified as highly expressed genes in TR-iBRB cells including GATA-binding protein-3 (GATA-3), cytosolic branched chain amino transferase (BCATc), and M-cadherin (cadherin-15). The rat M-cadherin gene was cloned from TR-iBRB cells, for the first time, and has >86% amino acid sequence identity to the previously cloned mammalian M-cadherins. Rat M-cadherin expression in TR-iBRB cells was much greater than that in TR-BBB cells as far as mRNA and protein levels were concerned.

CONCLUSIONS

M-cadherin, GATA-3, and BCATc are highly expressed in TR-iBRB cells compared with TR-BBB cells and may indeed be involved in unique functions at the inner BRB.

Evidence of GATA-3-dependent Th2 commitment during the in vivo immune response

The transcription factor GATA-3 has been shown to play an important role for the in vitro induction of T(h)2 cells. To clarify how the in vivo immune response is governed under GATA-3 function, we generated double-transgenic mice by crossing GATA-3 transgenic mice with ovalbumin (OVA)-specific TCR transgenic mice. After immunization with OVA, the double-transgenic mice showed increased expression of GATA-3 in antigen-reactive fresh CD4(+) T cells, and higher production of IL-5 and IL-13 in cultured spleen cells in the presence of cognate antigen without any polarizing conditions for T(h)2 cells. Moreover, the immunized double-transgenic mice showed a higher increase of in vivo secretion of IL-5 and IL-13 in bronchoalveolar lavage fluid after OVA aerosol challenging. The serum levels of OVA-specific IgG1, IgE and IgA antibodies were much higher in the immunized double-transgenic mice than TCR transgenic mice. These findings provide direct evidence that antigen-stimulated CD4(+) T cells in the immunized mice have already been committed into T(h)2 cells producing IL-5 and IL-13 selectively through enhanced GATA-3 expression in vivo, thereby inducing higher production of antigen-specific antibody for three isotypes other than IgM.

The role of Pax2 in mouse inner ear development

The paired box transcription factor, Pax2, is important for cochlear development in the mouse inner ear. Two mutant alleles of Pax2, a knockout and a frameshift mutation (Pax21Neu), show either agenesis or severe malformation of the cochlea, respectively. In humans, mutations in the PAX2 gene cause renal coloboma syndrome that is characterized by kidney abnormalities, optic nerve colobomas and mild sensorineural deafness. To better understand the role of Pax2 in inner ear development, we examined the inner ear phenotype in the Pax2 knockout mice using paint-fill and gene expression analyses. We show that Pax2-/- ears often lack a distinct saccule, and the endolymphatic duct and common crus are invariably fused. However, a rudimentary cochlea is always present in all Pax2 knockout inner ears. Cochlear outgrowth in the mutants is arrested at an early stage due to apoptosis of cells that normally express Pax2 in the cochlear anlage. Lack of Pax2 affects tissue specification within the cochlear duct, particularly regions between the sensory tissue and the stria vascularis. Because the cochlear phenotypes observed in Pax2 mutants are more severe than those observed in mice lacking Otx1 and Otx2, we postulate that Pax2 plays a key role in regulating the differential growth within the cochlear duct and thus, its proper outgrowth and coiling.

Effect of treatment of rheumatoid arthritis with infliximab on IFN gamma, IL4, T-bet, and GATA-3 expression: link with improvement of systemic inflammation and disease activity

OBJECTIVE

To study interferon gamma (IFN gamma) production and the expression of T-bet and GATA-3, the transcription factors associated with Th1 and Th2, in peripheral blood mononuclear cells (PBMC) from patients with rheumatoid arthritis before and during infliximab treatment, so as to distinguish between a disease specific and a disease activity dependent defect.

METHODS

Rheumatoid PBMC were obtained at weeks 0 and 6 of infliximab treatment and cultured for seven days with or without interleukin (IL)12 or the combination of IL12 and IL18. IFN gamma concentrations in supernatants were determined by ELISA. mRNA expression of IFN gamma, IL4, T-bet, and GATA-3 was determined by real time RT-PCR in whole blood at weeks 0 and 22.

RESULTS

A reduction in spontaneous IFN gamma production and in the response to Th1 inducing cytokines occurred in rheumatoid PBMC. Reduction of systemic inflammation with infliximab treatment increased IFN gamma production in response to IL12 or IL12+IL18. The IFN gamma/IL4 expression ratio of rheumatoid blood before treatment was lower than in healthy controls but was increased by infliximab treatment. T-bet expression or T-bet/GATA-3 ratio of rheumatoid blood was less than in controls. The T-bet/GATA-3 ratio was not influenced by infliximab treatment.

CONCLUSIONS

Regulation of T-bet and GATA-3 or IFN gamma and IL4 expression appeared different. The IFN gamma/IL4 ratio might express the blood Th1/Th2 balance better than the T-bet/GATA-3 ratio. Reduced IFN gamma production by rheumatoid PBMC and levels of IFN gamma and IL4 mRNA expression in blood were linked to disease improvement, indicating an association between this systemic Th1 feature and disease activity.

Cellular FLIP long form-transgenic mice manifest a Th2 cytokine bias and enhanced allergic airway inflammation

Cellular FLIP long form (c-FLIP(L)) is a caspase-defective homologue of caspase-8 that blocks apoptosis by death receptors. The expression of c-FLIP(L) in T cells can also augment extracellular signal-regulated kinase phosphorylation after TCR ligation via the association of c-FLIP(L) with Raf-1. This contributes to the hyperproliferative capacity of T cells from c-FLIP(L)-transgenic mice. In this study we show that activated CD4(+) T cells from c-FLIP(L)-transgenic mice produce increased amounts of Th2 cytokines and decreased amounts of Th1 cytokines. This correlates with increased serum concentrations of the Th2-dependent IgG1 and IgE. The Th2 bias of c-FLIP(L)-transgenic CD4(+) T cells parallels impaired NF-kappa B activity and increased levels of GATA-3, which contribute, respectively, to decreased IFN-gamma and increased Th2 cytokines. The Th2 bias of c-FLIP(L)-transgenic mice extends to an enhanced sensitivity to OVA-induced asthma. Taken together, these results show that c-FLIP(L) can influence cytokine gene expression to promote Th2-driven allergic reaction, in addition to its traditional role of blocking caspase activation induced by death receptors.

Interleukin (IL)-4-independent maintenance of histone modification of the IL-4 gene loci in memory Th2 cells

Interleukin (IL)-4-induced STAT6 activation and the subsequent up-regulation of GATA3 are crucial for the induction of chromatin remodeling of the Th2 cytokine gene loci as Th2 cells undergo development. This study probes the role of these molecules in the maintenance of memory Th2 cells. IL-4 was not required to maintain the capability for Th2 cytokine production in in vivo generated antigen-specific memory Th2 cells. Histone H3-K9/14 hyperacetylation and intergenic transcripts associated with the IL-4 gene locus were preserved in the absence of IL-4, but those associated with the IL-13 gene were partially IL-4-dependent. Histone H3-K4 methylation of the IL-13 and IL-4 gene loci was fully preserved in memory Th2 cells and accompanied by memory cell-specific accumulation of Pol II complex to highly restricted sites. Thus, memory Th2 cells maintain a unique Th2-specific remodeled chromatin in the IL-4 and IL-13 gene loci by active molecular events that are IL-4-independent.

Human Dendritic Cells Respond toHelicobacter pylori, Promoting NK Cell and Th1-Effector Responses In Vitro

Helicobacter pylori infection leads to chronic gastric inflammation. The current study determined the response of human APCs, NK cells, and T cells toward the bacteria in vitro. Human monocyte-derived dendritic cells (DC) were incubated with bacteria for 48 h. Intact H. pylori at a multitude of infection 5 stimulated the expression of MHC class II (4- to 7-fold), CD80, and CD86 B7 molecules (10- to 12-fold) and the CD83 costimulatory molecule (>30-fold) as well as IL-12 secretion (>50-fold) in DCs, and thereby, strongly induced their maturation and activation. CD56(+)/CD4(-) NK cells, as well as CD4(+)/CD45RA(+) naive T cells, were isolated and incubated with DCs pulsed with intact bacteria or different cellular fractions. Coculture of H. pylori-pulsed DCs with NK cells strongly potentiated the secretion of TNF-alpha and IFN-gamma. Coculture of naive T cells with H. pylori-pulsed DCs significantly enhanced TNF-alpha, IFN-gamma, and IL-2 secretion as well as T-bet mRNA levels, while GATA-3 mRNA was lowered. However, the effect appeared attenuated compared with coculture with Escherichia coli. A greater stimulation was seen with naive T cells and DCs pulsed with H. pylori membrane preparations. Intact H. pylori potently induced the maturation and activation of human monocyte-derived DC and thereby promote NK and Th1 effector responses. The strong activation of NK cells may be important for the innate immune response. Th1-polarized T cells were induced especially by incubation with membrane preparations of H. pylori, suggesting that membrane proteins may account for the specific adaptive immune response.

Instruction of distinct CD4 T helper cell fates by different notch ligands on antigen-presenting cells

Antigen-presenting cells (APC) tailor immune responses to microbial encounters by stimulating differentiation of CD4 T cells into the Th1 and Th2 lineages. We demonstrate that APC use the Notch pathway to instruct T cell differentiation. Strikingly, of the two Notch ligand families, Delta induces Th1, while Jagged induces the alternate Th2 fate. Expression of these different Notch ligands on APC is induced by Th1- or Th2-promoting stimuli. Th2 differentiation has been considered a default process as APC-derived instructive signals are unknown. We demonstrate that Jagged constitutes an instructive signal for Th2 differentiation, which is independent of IL4/STAT6. Th2 differentiation induced by APC is abrogated in T cells lacking the Notch effector RBPJkappa. Notch directs Th2 differentiation by inducing GATA3 and by directly regulating il4 gene transcription through RBPJkappa sites in a 3' enhancer.

Chromosome 10p deletion in a patient with hypoparathyroidism, severe mental retardation, autism and basal ganglia calcifications

Chromosome 10p terminal deletions have been associated with a DiGeorge like phenotype. Haploinsufficiency of the region 10p14-pter, results in hypoparathyroidism, sensorineural deafness, renal anomaly, that is the triad that features the HDR syndrome. Van Esch (2000) identified in a HDR patient, within a 200 kb critical region, the GATA3 gene, a transcription factor involved in the embryonic development of the parathyroids, auditory system and kidneys. We describe a new male patient, 33-year-old, with 10p partial deletion affected by hypocalcemia, basal ganglia calcifications and a severe autistic syndrome associated with mental retardation. Neurologically he presented severe impairment of language, hypotonia, clumsiness and a postural dystonic attitude. A peripheral involvement of auditory pathways was documented by auditory evoked potentials alterations. CT scan documented basal ganglia calcifications. Hyperintensity of the lentiform nuclei was evident at the MRI examination. Renal ultrasound scan was normal. Haploinsufficiency for GATA3 gene was documented with FISH analysis using cosmid clone 1.2. Phenotypic spectrum observed in del (10p) is more severe than the classical DGS spectrum. GATA3 has been found to regulate the development of serotoninergic neurons. A serotoninergic dysfunction may be linked with autism in this patient.

Utilizing Nottingham Prognostic Index in microarray gene expression profiling of breast carcinomas

We report a novel approach to gene expression profiling using the Nottingham Prognostic Index (NPI) to stratify 26 patients with invasive breast carcinoma. As an aggregate index of parameters reflecting metastatic potential, growth rate, and genetic instability the NPI has distinct advantages over other clinicopathologic features used to segregate breast cancer patients. As a continuous variable it offers a responsive and sensitive means of modeling a continuum of clinical aggressiveness. Using RNA extracted from 26 tumors and cDNA microarrays with 23 343 unique genetic elements, 84 genes and expressed sequence tags were identified whose expression patterns correlated with NPI. Differential expression by immunohistochemistry (IHC) was also observed for two of three genes evaluated by this method. Correlation was determined by the Spearman rank correlation method with null distribution analysis. Among the 84 genetic elements were seven previously implicated in neoplastic progression (including the two demonstrating differential expression by IHC), 11 without specific cancer association but localized to chromosomal sites whose loss or gain has been identified in cytogenetic studies of breast carcinoma, and 73 not previously associated with breast carcinoma. Collectively, the expression patterns of these 84 elements have potential to distinguish high and low NPI patient samples. These data add support to the assertion that prognostic groups of breast carcinoma are reflected in distinguishable expression profiles of a limited set of genes.

GATA-3 suppresses IFN-γ promoter activity independently of binding tocis-regulatory elements

The regulatory mechanism by which GATA-3 suppresses IFN-gamma gene expression was investigated. A reduction of GATA-3 using RNA interference technology enhanced, whereas overexpression of GATA-3 suppressed IFN-gamma mRNA expression. IL-4 expression was reciprocally affected by GATA-3. GATA-3-mediated down-regulation of IFN-gamma was achieved through the inhibition of its promoter/enhancer activity. Two GATA elements located in the cis-regulatory elements did not contribute to the suppression of IFN-gamma promoter activity, even though they behaved as binding sites for GATA-3. The effect of GATA-3 on IFN-gamma promoter was lost upon removal of the region encompassing -257 to -172. Among several transcription factors putatively interacting with this region, Stat4, which enhanced IFN-gamma promoter activity, was down-regulated by GATA-3 at gene transcription level. Although GATA-3 has the capacity to interact with the cis-regulatory elements, it suppresses IFN-gamma gene transcription via down-regulation of Stat4.

Hearing loss following Gata3 haploinsufficiency is caused by cochlear disorder

Patients with HDR syndrome suffer from hypoparathyroidism, deafness, and renal dysplasia due to a heterozygous deletion of the transcription factor GATA3. Since GATA3 is prominently expressed in both the inner ear and different parts of the auditory nervous system, it is not clear whether the deafness in HDR patients is caused by peripheral and/or central deficits. Therefore, we have created and examined heterozygous Gata3 knockout mice. Auditory brainstem response (ABR) thresholds of alert heterozygous Gata3 mice, analyzed from 1 to 19 months of age, showed a hearing loss of 30 dB compared to wild-type littermates. Neither physiological nor morphological abnormalities were found in the brainstem, cerebral cortex, the outer or the middle ear. In contrast, cochleae of heterozygous Gata3 mice showed significant progressive morphological degeneration starting with the outer hair cells (OHCs) at the apex and ultimately affecting all hair cells and supporting cells in the entire cochlea. Together, these findings indicate that hearing loss following Gata3 haploinsufficiency is peripheral in origin and that this defect is detectable from early postnatal development and maintains through adulthood.