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TM-25659 compound, a novel TAZ modulator, is developed for the control of bone loss and obesity. TAZ is known to bind to a variety of transcription factors to control cell differentiation and organ development. A selective and sensitive method was developed for the determination of TM-25659 concentrations in rat plasma. The drug was measured by liquid chromatography–tandem mass spectrometry after liquid–liquid extraction with ethyl acetate. TM-25659 and the internal standard imipramine were separated on a Hypersil GOLD C18 column with a mixture of acetonitrile–ammonium formate (10 mM) (90:10, v/v) as the mobile phase. The ions m/z 501.2 → 207.2 for TM-25659 and m/z 281.0 → 86.0 for imipramine in multiple reaction monitoring mode were used for the quantitation. The calibration range was 0.1–100 μg/ml with a correlation coefficient greater than 0.99. The lower limit of quantitation of TM-25659 in rat plasma was 0.1 μg/ml. The percent recoveries of TM-25659 and imipramine were 98.6% and 95.7% from rat plasma, respectively. The intra- and inter-batch precisions were 3.17–15.95% and the relative error was 0.38–10.82%. The developed assay was successfully applied to a pharmacokinetic study of TM-25659 administered intravenously (10 mg/kg) to rats.

It is believed that the inherent differentiation program of melanocytes during embryogenesis predisposes melanoma cells to high frequency of metastasis. Sox10, a transcription factor expressed in neural crest stem cells and a subset of progeny lineages, plays a key role in the development of melanocytes. We show that B16F10 melanoma cells transfected with siRNAs specific for Sox10 display reduced migratory activity which in turn indicated that a subset of transcriptional regulatory target genes of Sox10 is likely to be involved in migration and metastasis of melanoma cells. We carried out a microarray-based gene expression profiling using a Sox10-specific siRNA to identify relevant regulatory targets and found that multiple genes including melanocortin-1 receptor (Mc1r) partake in the regulation of migration. We provide evidences that the effect of Sox10 on migration is mediated in large part by Mitf, a transcription factor downstream to Sox10. Among the mouse melanoma cell lines examined, however, only B16F10 showed robust down-regulation of Sox10 and inhibition of cell migration indicating that further dissection of dosage effects and/or cell line-specific regulatory networks is necessary. The involvement of Mc1r in migration was studied in detail in vivo using a murine metastasis model. Specifically, B16F10 melanoma cells treated with a specific siRNA showed reduced tendency in metastasizing to and colonizing the lung after being injected in the tail vein. These data reveal a cadre of novel regulators and mediators involved in migration and metastasis of melanoma cells that represents potential targets of therapeutic intervention.

Overactive responses by interleukin 17 (IL-17)-producing helper T cells (T(H)17 cells) are tightly linked to the development of autoimmunity, yet the factors that negatively regulate the differentiation of this lineage remain unknown. Here we report that the transcription factor T-bet suppressed development of the T(H)17 cell lineage by inhibiting transcription of Rorc (which encodes the transcription factor RORγt). T-bet interacted with the transcription factor Runx1, and this interaction blocked Runx1-mediated transactivation of Rorc. T-bet Tyr304 was required for formation of the T-bet-Runx1 complex, for blockade of Runx1 activity and for inhibition of the T(H)17 differentiation program. Our data reinforce the idea of master regulators that shape immune responses by simultaneously activating one genetic program while silencing the activity of competing regulators in a common progenitor cell.

Myoblast differentiation is indispensable for skeletal muscle formation and is governed by the precisely coordinated regulation of a series of transcription factors, including MyoD and myogenin, and transcriptional coregulators. TAZ (transcriptional coactivator with PDZ-binding motif) has been characterized as a modulator of mesenchymal stem cell differentiation into osteoblasts and adipocytes through its regulation of lineage-specific master transcription factors. In this study, we investigated whether TAZ affects myoblast differentiation, which is one of the differentiated lineages of mesenchymal stem cells. Ectopic overexpression of TAZ in myoblasts increases myogenic gene expression in a MyoD-dependent manner and hastens myofiber formation, whereas TAZ knockdown delays myogenic differentiation. In addition, enforced coexpression of TAZ and MyoD in fibroblasts accelerates MyoD-induced myogenic differentiation. TAZ physically interacts with MyoD through the WW domain and activates MyoD-dependent gene transcription. TAZ additionally enhances the interaction of MyoD with the myogenin gene promoter. These results strongly suggest that TAZ functions as a novel transcriptional modulator of myogenic differentiation by promoting MyoD-mediated myogenic gene expression.

G12 family have been known to modulate a variety of cellular events such as cell migration, B cell activation and maturation, cytokine production, and cell differentiation. In particular, Galpha12 modulates IgG production, thus induces IgG antibody-mediated immune responses. However, it is largely unknown whether Galpha12 is required for T cell-mediated immune functions. In this study, we investigated the effects of Galpha12 in the activation and differentiation of CD4+ T cells. While PMA plus ionomycin induced equal levels of IL-2 production in WT and Galpha12-deficient lymphocytes, TCR-triggered IL-2 production was significantly attenuated in Galpha12 KO lymphocytes. In particular, CD4+ T cells and effector Th cells lacking of Galpha12 revealed diminished IL-2 production, but not IFNgamma production, upon TCR stimulation. In addition, supplement of IL-2 preferentially induced Galpha12-deficient CD4+ T cells into Th2 and Th17 cells; however, the expression of specific transcription factors was unchanged in Galpha12 KO Th cells. While IL-2 expression was still diminished by the re-stimulation with anti-CD3, PMA plus ionomycin restored IL-2 production in Galpha12-deficient Th1 and Th2 cells. These results suggest that Galpha12 may be a critical signaling molecule in TCR-induced IL-2 production and also relay a signal to suppress Th2 and Th17 cell differentiation.

T-box-containing protein expressed in T cells (T-bet) is a master transcription factor for the development of interferon (IFN) gamma-producing T helper 1 (Th1) cells and also functions in other immune cells including natural killer (NK), cytotoxic T lymphocytes and dendritic cells. T-bet-deficient mice increased susceptibility to viral infection and tumor development due to the defective functions of immune cells. T-bet is known to play a key role in NK-mediated antimetastatic response; however, it remains to be characterized whether T-bet is essential for in vivo tumor suppression mediated by T cells. Here, we have investigated in vivo tumor suppression effect of T-bet-restored T cells using T cell-specific and inducible T-bet transgenic mice generated in a T-bet-deficient background. T-bet-null mice increased susceptibility to tumor development, whereas induction of T cell-specific T-bet expression upon melanoma cell injection substantially suppressed tumor development by inducing IFNgamma production in T cells and tumor cell apoptosis. Late induction of T-bet expression in tumor-bearing mice produced comparable amounts of IFNgamma with control and significantly decreased tumor volume. In addition, increased melanoma lung metastasis in T-bet-deficient mice was strikingly inhibited by T-bet restoration in T cells. Intravenous injection of activated Th1 cells, not T-bet-null Th1 cells, attenuated metastatic melanoma progression, in addition, restoration of T-bet in T-bet-null Th1 cells certainly retrieved antimetastatic activity. These results suggest that T-bet expression in T cells is crucial for the control of tumor development and antimetastatic activity.

Background Translationally Controlled Tumor Protein (TCTP) found in nasal lavage fluids of allergic patients was named IgE-dependent histamine-releasing factor (HRF). Human recombinant HRF (HrHRF) has been recently reported to be much less effective than HRF produced from activated mononuclear cells (HRFmn). Methods and Findings We found that only NH2-terminal truncated, but not C-terminal truncated, TCTP shows cytokine releasing activity compared to full-length TCTP. Interestingly, only NH2-terminal truncated TCTP, unlike full-length TCTP, forms dimers through intermolecular disulfide bonds. We tested the activity of dimerized full-length TCTP generated by fusing it to rabbit Fc region. The untruncated-full length protein (Fc-HrTCTP) was more active than HrTCTP in BEAS-2B cells, suggesting that dimerization of TCTP, rather than truncation, is essential for the activation of TCTP in allergic responses. We used confocal microscopy to evaluate the affinity of TCTPs to its putative receptor. We detected stronger fluorescence in the plasma membrane of BEAS-2B cells incubated with Del-N11TCTP than those incubated with rat recombinant TCTP (RrTCTP). Allergenic activity of Del-N11TCTP prompted us to see whether the NH2-terminal truncated TCTP can induce allergic airway inflammation in vivo. While RrTCTP had no influence on airway inflammation, Del-N11TCTP increased goblet cell hyperplasia in both lung and rhinal cavity. The dimerized protein was found in sera from allergic patients, and bronchoalveolar lavage fluids from airway inflamed mice. Conclusions Dimerization of TCTP seems to be essential for its cytokine-like activity. Our study has potential to enhance the understanding of pathogenesis of allergic disease and provide a target for allergic drug development.

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a ligand-activated transcription factor that plays a pivotal role in the modulation of gene expression involved in adipocyte differentiation and insulin sensitivity. It has been previously established that thiazolidinedione (TZD) PPARgamma ligands such as rosiglitazone have potent anti-diabetic and adipogenic activities. A novel non-TZD ligand for PPARgamma, KR62980 has recently been characterized to increase insulin sensitivity and to be weakly adipogenic in 3T3-L1 cells or anti-adipogenic in rosiglitazone-induced adipocyte differentiation. In this study, we have confirmed that KR62980 substantially suppresses rosiglitazone-induced adipocyte differentiation and attenuates adipogenic gene expression via an induced reduction in PPARgamma activity. KR62980 increased the nuclear localization of TAZ, a PPARgamma suppressor, and also enhanced the interaction between PPARgamma and TAZ, thus resulting in the TAZ-mediated suppression of PPARgamma activity. Furthermore, KR62980 failed to suppress PPARgamma-mediated adipogenic gene expression and adipocyte differentiation in TAZ knockdown 3T3-L1 cells, thus indicating a TAZ-dependent suppressive activity of KR62980 on PPARgamma-mediated function. These findings strongly suggest that the novel PPARgamma ligand, KR62980, may prove to be beneficial to anti-adipogenic function through the suppression of PPARgamma-mediated adipocyte differentiation by activating TAZ.

Interleukin-13 (IL-13) has been proposed as a therapeutic target for bronchial asthma as it plays crucial roles in the pathogenesis of the disease. We developed an in vitro test system measuring transcriptional downregulatory activities on IL-13 as a primary screening method to select drug candidates from natural products. The promoter region of IL-13 (-2,048 to +1) was cloned into the upstream of a luciferase gene in the plasmid pGL4.14 containing the hygromycin resistance gene as a selection marker, generating pGL4.14-IL-13. The EL-4 thymoma and RBL-2H3 mast cells transiently expressing this plasmid highly produced the luciferase activities by responding to PI (PMA and ionomycin) stimulation up to 8-fold and 13-fold compared with the control, respectively, whereas cyclosporin A, a wellknown antiasthmatic agent, significantly downregulated the activities. The BF1 clone of RBL-2H3 cells constitutively expressing pGL4.14-IL-13 was established by selecting surviving cells under a constant lethal dose of hygromycin treatment. The feasibility of this system was evaluated by measuring the downregulatory activities of 354 natural products on the IL-13 promoter using the BF1 clone. An extract from Morus bombycis (named TBRC 156) significantly inhibited PI-induced luciferase activities and IL-13 mRNA expression, but not the protein expression. Fisetin (named TBRC 353) inhibited not only PI-induced luciferase activities and mRNA expression, but also the IL-13 protein secretion, whereas myricetin (named TBRC 354) could not suppress the IL-13 expression at all. Our data indicated that this in vitro test system is able to discriminate the effects on IL-13 expression, and furthermore, that it might be suitable as a simple and time-saving primary screening system to select antiasthmatic agents by measuring transcriptional activities of the IL-13 promoter.

Background Extracellular translationally controlled tumor protein (TCTP) is known to play a role in human allergic responses. TCTP has been identified outside of macrophages, in activated mononuclear cells, and in biological fluids from allergic patients. Even TCTP devoid of signal sequences, is secreted to extracellular environment by an yet undefined mechanism. This study is aimed at understanding the mechanism of TCTP release and its regulation. A secondary goal is to see if inhibitors of TCTP release can serve as potential anti-allergic asthmatic drugs. Methodology/Principal Findings Using Western blotting assay in HEK293 and U937 cells, we found that TCTP secretion is reduced by omeprazole and pantoprazole, both of which are proton pump inhibitors. We then transfected HEK293 cells with proton pump expression vectors to search for the effects of exogeneously overexpressed H+/K+-ATPase on the TCTP secretion. Based on these in vitro data we checked the in vivo effects of pantoprazole in a murine model of ovalbumin-induced allergy. Omeprazole and pantoprazole reduced TCTP secretion from HEK293 and U937 cells in a concentration-dependent fashion and the secretion of TCTP from HEK293 cells increased when they over-expressed H+/K+-ATPase. In a murine model of ovalbumin-induced allergy, pretreatment with pantoprazole reduced infiltration of inflammatory cells, increased goblet cells, and increased TCTP secretion induced by OVA challenge. Conclusion Since Omeprazole and pantoprazole decrease the secretion of TCTP which is associated with the development of allergic reaction, they may have the potential to serve as anti-allergic (asthmatic) drugs.

Naturally occurring phenolic compounds, such as chavicol analogues, have been shown to have potent antioxidant and anti-inflammatory activities. We have previously isolated two chavicol acetate analogues, acetoxychavicol acetate (ACA) and hydroxychavicol acetate (HCA) from the rhizomes of Alpinia galanga. Although the function of ACA has been studied in many systems, the function of HCA has yet to be systemically examined. In this study, we have comparably examined the functions of ACA and HCA on the cytokine production in Th cells. ACA exhibited potent antioxidant activity and increased cell apoptosis; therefore, cytokine production by Th cells was diminished. Although HCA had neither antioxidant activity nor pro-apoptotic function, it was shown to increase IL-2 production and attenuate IFNgamma expression in Th cells. In addition, we demonstrated that HCA suppressed T-bet expression, which is responsible for IL-2 suppression and IFNgamma induction in Th cells and inhibited T-bet-mediated Th1 cell differentiation. Therefore, we suggest that HCA may be beneficial as therapeutics for treating inflammatory immune disorders caused by extravagant activation of Th1-mediated immune responses.

Antitumor responses depend on type 1 immunity, which is severely impaired in mice deficient for the T-box expressed in T cells (T-bet) transcription factor. Both T-bet-deficient (T-bet−/−) NK and CTL show defective function, which can be overcome by strong stimuli due to the expression of eomesodermin, another member of the T-box family. The effective response from T-bet−/− mice to viral infection and tumor initiation corroborates with these findings. However, T-bet−/− animals fail to control cancer metastasis and are, therefore, highly susceptible to tumor spread. The mechanism of T-bet-dependent resistance to metastatic disease is not known. In this study, we show that T-bet plays a role in inhibiting cancer metastasis by regulating the longevity and function of NK cells. Our data demonstrate that the absence of a proper innate immune response driven by NK cells in T-bet−/− mice precludes the initiation of a potent adaptive response to tumors. Adoptive transfer of wild-type activated NK cells protects T-bet−/− animals after melanoma challenge showing that reconstitution of the NK compartment in these mice is sufficient to mediate a significant reduction in tumor burden. Transfer of T-bet−/− A-NK cells fails to do so, due to their reduced in vivo survival, inefficient lysis of cancer cells, and poor IFN-γ production. Taken together, these results show for the first time an irreplaceable role for T-bet in the NK-mediated cross-talk between innate and adaptive immune responses to metastatic disease.

Natural compounds possessing naphthopyran moiety have been attracted by their anti-bacterial, anti-fungal, and anti-viral activities, as well as anti-tumor activities. Although chemical structures were critical for the potential biological activities, the detailed functional mechanisms remained unclear. Here, we have studied the effects of naphthopyran derivatives (eleutherin, isoeleutherin, and eleutherinol) on T helper cell-mediated immune responses to understand the mechanisms of their anti-microbial and anti-tumor activities. The study revealed that isoeleutherin, which has 1,4-naphthoquinone ring with alpha-methyl group, selectively and specifically stimulated IFNgamma production through the activation of T-bet gene transcription, thus enhancing Th1-mediated immune responses. However, a natural naphthopyran-4-one, eleutherinol dramatically inhibited both IFNgamma and IL-2 productions during Th cell activation by suppressing the gene transcriptions of cytokines. Therefore, we suggest that the chemical modification and chirality of naphthopyran moiety in isoeleutherin and eleutherinol may be critical for the selective modulation of T helper cell-mediated immune responses.

Quercetin is a popular flavonoid compound that is biosynthesized by plants; it is suggested to modulate a variety of inflammatory responses of macrophages and T lymphocytes. Oral administration of quercetin in arthritic rats dramatically diminishes clinical signs of arthritis. Moreover, quercetin ameliorates experimental autoimmune encephalomyelitis, which is associated with Th1-mediated immune responses. Like quercetin inhibits macrophage-induced cytokine production, it also blocks IL-12-dependent JAK-STAT signaling in Th cells. Despite the anti-inflammatory effects of quercetin acting through Th cells, the regulatory mechanisms remain unclear. Here, we studied the function of quercetin in Th cells and found that quercetin suppressed both IFNgamma and IL-2 production upon T cell receptor stimulation. Furthermore, we uncovered the regulatory mechanisms of quercetin involved in the inhibition of cytokine production during Th cell activation. The fact that quercetin-derived IFNgamma suppression was blocked in T-bet-deficient Th cells demonstrated quercetin act through the modulation of T-bet expression. Whereas IL-2 inhibition by quercetin was independent of T-bet expression, quercetin diminished IL-2R alpha expression, which is critical for positive regulatory loop of IL-2 autoactivation. Taken together, quercetin is suggested to repress both IFNgamma and IL-2 cytokine production by independent mechanisms; T-bet-dependent IFNgamma suppression and IL-2R alpha-dependent IL-2 inhibition.

T-bet is a critical transcription factor that regulates differentiation of Th1 cells from CD4(+) precursor cells. Since T-bet directly binds to the promoter of the IFN-γ gene and activates its transcription, T-bet deficiency impairs IFN-γ production in Th1 cells. Interestingly, T-bet-deficient Th cells also display substantially augmented the production of IL-2, a T cell growth factor. Exogenous expression of T-bet in T-bet deficient Th cells rescued the IFN-γ production and suppressed IL-2 expression. IFN-γ and IL-2 reciprocally regulate Th cell proliferation following TCR stimulation. Therefore, we examined the effect of T-bet on Th cell proliferation and found that T-bet deficiency significantly enhanced Th cell proliferation under non-skewing, Th1-skewing, and Th2-skewing conditions. By using IFN-γ-null mice to eliminate the anti-proliferative effect of IFN-γ, T-bet deficiency still enhanced Th cell proliferation under both Th1- and Th2-skewing conditions. Since the anti-proliferative activity of T-bet may be influenced by IL-2 suppression in Th cells, we examined whether T-bet modulates IL-2-independent cell proliferation in a non-T cell population. We demonstrated that T-bet expression induced by ecdysone treatment in human embryonic kidney (HEK) cells increased IFN-γ promoter activity in a dose dependent manner, and sustained T-bet expression considerably decreased cell proliferation in HEK cells. Although the molecular mechanisms underlying anti-proliferative activity of T-bet remain to be elucidated, T-bet may directly suppress cell proliferation in an IFN-γ- or an IL-2-independent manner.

The osteopontin (Opn) glycoprotein has been implicated in diverse physiological processes, including vascularization, bone formation, and inflammatory responses. Studies of its role in immune responses has suggested that Opn can set the early stage of type-1 immune (cell-mediated) responses through differential regulation of IL-12 and IL-10 cytokine gene expression in macrophages. Although Opn has been suggested to play a role in the development of type-1 immunity, little is known about control of Opn gene expression. Here, we report that Opn gene expression in activated T cells, but not macrophages, is regulated by T-bet, a transcription factor that controls CD4 + T helper (Th1) cell lineage commitment. We also find that T-bet-dependent expression of Opn in T cells is essential for efficient skewing of CD4 + T and CD8 + T cells toward the Th1 and type 1 CD8 + T cells (Tc1) pathway, respectively. Taken together, these findings begin to delineate the genetic basis of Opn expression in T cells and further clarify the role of Opn in Th and Tc1 development.

Mesenchymal stem cells (MSCs) are a pluripotent cell type that can differentiate into several distinct lineages. Two key transcription factors, Runx2 and peroxisome proliferator–activated receptor γ (PPARγ), drive MSCs to differentiate into either osteoblasts or adipocytes, respectively. How these two transcription factors are regulated in order to specify these alternate cell fates remains a pivotal question. Here we report that a 14-3-3–binding protein, TAZ (transcriptional coactivator with PDZ-binding motif), coactivates Runx2-dependent gene transcription while repressing PPARγ-dependent gene transcription. By modulating TAZ expression in model cell lines, mouse embryonic fibroblasts, and primary MSCs in culture and in zebrafish in vivo, we observed alterations in osteogenic versus adipogenic potential. These results indicate that TAZ functions as a molecular rheostat that modulates MSC differentiation.

TBX21 encodes for the transcription factor T-bet (T-box expressed in T cells), which influences naïve T lymphocyte development and has been implicated in asthma pathogenesis. Specifically, the T-bet knockout mouse spontaneously develops airway hyperresponsiveness and other changes consistent with asthma. Because airway responsiveness is moderated by the use of inhaled corticosteroids in asthma, it is conceivable that genetic variation in TBX21 may alter asthma phenotypes in a treatment-specific fashion. Here we demonstrate that the nonsynonymous variation in TBX21 coding for replacement of histidine 33 with glutamine is associated with significant improvement in the PC 20 (a measure of airway responsiveness) of asthmatic children in a large clinical trial spanning 4 years. We note that this increase occurs only in the children randomized to inhaled corticosteroids and that it dramatically enhances the overall improvement in PC 20 associated with inhaled corticosteroid usage. The average PC 20 at trial end for subjects on inhaled corticosteroids possessing a variant allele was in the normal range for nonasthmatics. In cellular models, we show that the TBX21 variant increases T helper 1 and decreases T helper 2 cytokine expression comparably with wild type. TBX21 may thus be an important determinant pharmacogenetic response to the therapy of asthma with inhaled corticosteroids.

T-bet, a T-box transcription factor, is expressed in CD4+ T lymphocytes committed to Th1 T-cell development and in a subset of T-cell non-Hodgkin lymphomas. Recent evidence indicates that T-bet also is expressed in B lymphocytes and might participate in immunoglobulin class switching. We examined T-bet expression in 116 cases of B-cell lymphoproliferative disorders by immunostaining and found that T-bet was expressed consistently in precursor B-cell lymphoblastic leukemia/lymphoblastic lymphoma (14/14 cases) in contrast with precursor T-cell lymphoblastic leukemia/lymphoblastic lymphoma, which is consistently T-bet- (13 cases), as previously reported. T-bet is expressed in memory B cell-derived neoplasms (chronic lymphocytic leukemia, marginal zone lymphoma, hairy cell leukemia; 35/42 cases) but not in cases of mantle cell, follicular, and large cell lymphoma (43 cases). Expression of T-bet in precursor B-cell lymphoblastic leukemia/lymphoblastic lymphoma was confirmed by Western blot analysis. The expression of T-bet in a significant subset of B-cell lymphoproliferative disorders but not in the vast majority of reactive B cells suggests it might have a role in the oncogenesis of T-bet+ B-cell neoplasms. In addition, T-bet should serve as a useful new marker for the diagnosis and subtyping of B-cell lymphoproliferative disorders.

c-maf is a T helper (Th)2 cell-specific transcription factor, which promotes the differentiation of Th2 cells mainly by an IL-4-dependent mechanism. It remains unclear whether c-maf possesses any IL-4-independent function in regulating the production of Th2 cytokines. Here, we provide evidence demonstrating that c-maf, independent of IL-4, is essential for normal induction of CD25 in developing Th2 cells. The levels of CD25 are significantly higher in developing Th2 cells than in developing Th1 cells duringin vitrodifferentiation. In addition, timely blockade of IL-2 receptor signaling selectively inhibits the production of Th2 cytokines, but not IFN-γ or IL-2. Taken together, our results uncover an IL-4-independent and CD25-mediated function of c-maf in promoting the production of Th2 cytokines.

Fliz1 (fetal liver zinc finger protein 1) is a novel zinc finger protein preferentially expressed in fetal liver hematopoietic progenitors and in several adult organs, including the thymus. To investigate the in vivo function of Fliz1 in regulating the development of T cell lineage, we generated and studied transgenic mice overexpressing human Fliz1 in a T-cell specific and inducible manner. We found that overexpression of human Fliz1 in adult animals resulted in a substantial decrease in total number of thymocytes due to enhanced apoptosis, whereas maturation of thymocytes remained undisturbed. The Fliz1-induced apoptosis is dependent on the N-terminus of Fliz1, which contains an acidic and a serine-rich domains, and might be due to augmented expression of bad, a pro-apoptotic gene. Taken together, our data suggest that Fliz1 plays a role in regulating thymocyte homeostasis.

We examined cAMP response element (CRE)-binding proteins involved in lactate dehydrogenase A (LDHA)-gene transcription in rat liver after partial hepatectomy. Gel retardation and Southwestern blot assays showed that the CRE-binding activity of the 11-16 kDa novel proteins increased in accordance with increases in LDH A-mRNA in regenerating liver tissues, whereas that of the 43 kDa CREB did not. Using CRE-oligonucleotide affinity chromatography and reverse-phase HPLC, we purified four CRE-binding proteins of 11.2, 15.2, 15.8, and 16.3 kDa. N-terminal amino acid sequences of 15.2 and 16.3 kDa proteins revealed a high sequence homology to but were not identical with those of rat histone H2A.1 and H2B, respectively. CRE-bindings of these two proteins were highly specific, while those of histones H2A.1 and H2B were nonspecific as shown by competition-Southwestern blot and DNase I footprinting assays. Taking these data together, we suggest that the novel 11-16 kDa CRE-binding proteins are responsible for the cell growth-dependent inducibility of LDH A-gene transcription during liver regeneration.

Lee, C.-G., H.-K. Kwon, A. Sahoo, W. Hwang, J.-S. So, J.-S. Hwang, C.-S. Chae, G.-C. Kim, J.-E. Kim, H.-S. So, E. S. Hwang, R. Grenningloh, I-C. Ho, and S.-H. Im. 2012. Interaction of Ets-1 with HDAC1 represses IL-10 expression in Th1 cells. J. Immunol . 188: [2244–2253][1]. An additional funding

Background NADPH oxidase (NOX) modulates cell proliferation, differentiation and immune response through generation of reactive oxygen species. Particularly, NOX2 is recently reported to be important for regulating Treg cell differentiation of CD4+ T cells. Methods We employed ovalbumin-induced airway inflammation in wild-type and NOX2-deficient mice and analyzed tissue histopathology and cytokine profiles. Results We investigated whether NOX2-deficiency affects T cell-mediated airway inflammation. Ovalbumin injection which activates T cell-mediated allergic response increased airway inflammation in wild-type mice, as evidenced by increased immune cell infiltration, allergic cytokine expression, and goblet cell hyperplasia in the lung. Interestingly, NOX2 knockout (KO) mice were more susceptible to allergen-induced lung inflammation compared to wild-type mice. Immune cells including neutrophils, lymphocytes, macrophages, and eosinophils were drastically infiltrated into the lung of NOX2 KO mice and mucus secretion was substantially increased in deficiency of NOX2. Furthermore, inflammatory allergic cytokines and eotaxin were significantly elevated in NOX2 KO mice, in accordance with enhanced generation of inflammatory cytokines interleukin-17 and interferon-γ by CD4+ T cells. Conclusion These results indicate that NOX2 deficiency favorably produces inflammatory cytokines by T cells and thus increases the susceptibility to severe airway inflammation.

Background A T H 1-specific transcription factor, T-box–containing protein expressed in T cells (T-bet), controls the production of both T H 1 and T H 2 cytokines in T H cell differentiation by means of distinct mechanisms. T-bet–deficient mice overproduce T H 2 cytokines and have spontaneous airway inflammation. Objectives We tested whether T-bet overexpression could protect against the development or progression of asthma. Methods We generated a T cell–specific and inducible line of T-bet–transgenic mice on a T-bet–deficient genetic background and used it to study the function of T-bet in an ovalbumin (OVA)–induced asthma model. Results Induction of T-bet in a T cell–specific manner in an OVA model of asthma concomitant with OVA injection prevented airway hyperresponsiveness, eosinophilic and lymphocytic inflammation, and IL-5 and IL-13 production in bronchoalveolar lavage fluid and also reduced serum IgE and T H 2 cytokine production by peripheral T cells. Even when T-bet expression was induced during later stages of asthma progression, T-bet overexpression still attenuated airway hyperresponsiveness and goblet cell hyperplasia, as well as T H 2 cytokine production. Conclusions Our results suggest that T-bet expression in T cells can prevent the initiation of airway inflammation and progression of chronic inflammation and might be extrapolated to human asthma.

Both acute myeloid leukemia 1 and c-Fos are regulatory factors of hematopoietic cell differentiation. We identified that the c-fos promoter contains an acute myeloid leukemia 1 binding site at nucleotide positions −6–+14. c-fos promoter activity was induced by transient overexpression of acute myeloid leukemia 1 in Jurkat T-cells, but not by that of the short form of acute myeloid leukemia 1-MTG8, a chimeric acute myeloid leukemia 1 protein. In 32Dcl3 myeloid cells, stable overexpression of acute myeloid leukemia 1-MTG8 blocked the c-fos gene transcription and cell differentiation, but that of acute myeloid leukemia did not. These data suggest that acute myeloid leukemia 1 and acute myeloid leukemia 1-MTG8 reciprocally regulate the myeloid cell differentiation, possibly by the way of regulating c-fos gene transcription.