P19 Expression Research Articles

C-Rel Is Essential for the Development of Innate and T Cell-Induced Colitis

Inflammatory bowel disease is a chronic inflammatory response of the gastrointestinal tract mediated in part by an aberrant response to intestinal microflora. Expression of IL-23 subunits p40 and p19 within cells of the innate immune system plays a central role in the development of lower bowel inflammation in response inflammatory challenge. The NF-kappaB subunit c-Rel can regulate expression of IL-12/23 subunits suggesting that it could have a critical role in mediating the development of chronic inflammation within the lower bowel. In this study, we have analyzed the role of c-Rel within the innate immune system in the development of lower bowel inflammation, in two well-studied models of murine colitis. We have found that the absence of c-Rel significantly impaired the ability of Helicobacter hepaticus to induce colitis upon infection of RAG-2-deficient mice, and ameliorated the ability of CD4(+)CD45RB(high) T cells to induce disease upon adoptive transfer into RAG-deficient mice. The absence of c-Rel interfered with the expression of IL-12/23 subunits both in cultured primary macrophages and within the colon. Thus, c-Rel plays a critical role in regulating the innate inflammatory response to microflora within the lower bowel, likely through its ability to modulate expression of IL-12/23 family members.

Opposing roles for p16Ink4a and p19Arf in senescence and ageing caused by BubR1 insufficiency

Expression of p16(Ink4a) and p19(Arf) increases with age in both rodent and human tissues. However, whether these tumour suppressors are effectors of ageing remains unclear, mainly because knockout mice lacking p16(Ink4a) or p19(Arf) die early of tumours. Here, we show that skeletal muscle and fat, two tissues that develop early ageing-associated phenotypes in response to BubR1 insufficiency, have high levels of p16(Ink4a) and p19(Arf). Inactivation of p16(Ink4a) in BubR1-insufficient mice attenuates both cellular senescence and premature ageing in these tissues. Conversely, p19(Arf) inactivation exacerbates senescence and ageing in BubR1 mutant mice. Thus, we identify BubR1 insufficiency as a trigger for activation of the Cdkn2a locus in certain mouse tissues, and demonstrate that p16(Ink4a) is an effector and p19(Arf) an attenuator of senescence and ageing in these tissues.

The 3′UTR 1188 A/C polymorphism in the interleukin- 12p40 gene ( IL-12B) is associated with lepromatous leprosy in the west of Mexico

Leprosy is a chronic infectious disease caused by Mycobacterium leprae. IL-12 participates in the immune response against M. leprae by regulating T cell differentiation into the Th1-type response. Several single nucleotide polymorphisms have been identified in the IL-12 gene such as 3′UTR 1188 A/C polymorphism, which is associated with different diseases. However, the relationship of this polymorphism with the immune response in leprosy has not been explored. In this case–control study, we evaluated 44 patients with lepromatous leprosy (LL) and 51 healthy subjects (HS). We aimed to determine the relationship between 3′UTR 1188 A/C polymorphism of IL-12 p40, mRNA expression, and soluble IL-12 concentration in LL patients and HS. Genotype frequencies were 41% A/A, 36% A/C, and 23% C/C in LL patients, and 47% A/A, 49% A/C, and 4% C/C in HS ( p < 0.05). LL patients had a lower mRNA expression of IL-12 p40 gene, whereas HS had a higher expression level. Soluble IL-12 p40 concentration was higher in LL patients than in HS ( p < 0.05). IL-12 p70 concentration did not differ between groups, and IL-12 p40 concentration was not significantly correlated with mRNA expression in either group. These data suggest that IL-12 p40 3′UTR 1188 A/C polymorphism is associated with greater susceptibility to lepromatous leprosy in patients from western Mexico, independently of IL-12 p40 and p70 expression levels.

Abundant expression of the interleukin (IL)23 subunit p19, but low levels of bioactive IL23 in the rheumatoid synovium: differential expression and Toll-like receptor-(TLR) dependent regulation of the IL23 subunits, p19 and p40, in rheumatoid arthritis

Objective:Interleukin (IL)23, composed of a p19 and a p40 subunit, is suggested to play key roles in rheumatoid arthritis (RA), dependent on the promotion and proliferation of IL17-producing T helper...

Upregulation of HTLV‐1 and HTLV‐2 expression by HIV‐1 in vitro

Co-infections with HIV-1 and the human T leukemia virus types 1 and 2 (HTLV-1, HTLV-2) occur frequently, particularly in large metropolitan areas where injection drug use is a shared mode of transmission. Recent evidence suggests that HIV-HTLV co-infections are associated with upregulated HTLV-1/2 virus expression and disease. An in vitro model of HIV-1 and HTLV-1/2 co-infection was utilized to determine if cell free HIV-1 virions or recombinant HIV-1 Tat protein (200-1,000 ng/ml) upregulated HTLV-1/2 expression and infectivity. Exposure to HIV-1 increased the number of HTLV-1 antigen expressing cells, from 6% at baseline to 12% at 24 hr, and 20% at 120 hr (P < 0.05) post-exposure. A similar, although less robust response was observed in HTLV-2 infected cells. HIV-1 co-localized almost exclusively with HTLV-1/2 positive cells. Exposure to HIV-1 Tat protein (1,000 ng/ml) increased HTLV-1 p19 expression almost twofold by 48 hr, and cells co-stimulated with 10 nM phorbol myristate acetate (PMA) showed almost a fourfold increase over baseline. It is concluded that HIV-1 augments HTLV-1/2 infectivity in vitro. The findings also suggest a role for the HIV-1 Tat protein and PMA-inducible cellular factors, in HIV-1 induced HTLV-1/2 antigen expression.

Anandamide inhibits IL-12p40 production by acting on the promoter repressor element GA-12: possible involvement of the COX-2 metabolite prostamide E2

The eCB [endoCB (cannabinoid)] system is being considered as a novel therapeutic target for immune disorders. Cytokines of the IL-12 (interleukin-12) family have essential functions in cell-mediated immunity. In the present study, we have addressed the mechanisms of action of the eCB AEA (anandamide) on the regulation of IL-12p40 in activated microglia/macrophages. We demonstrated that AEA can inhibit the expression of p35, p19 and p40 subunits, which form the biologically-active cytokines IL-12 and IL-23 in microglia stimulated with LPS (lipopolysaccharide)/IFNgamma (interferon gamma). Additionally, we have provided evidence that AEA reduces the transcriptional activity of the IL-12p40 gene in LPS- and IFNgamma-co-activated cells, and this is independent of CB or vanilloid receptor activation. Site-directed mutageneis of the different elements of the p40 promoter showed that AEA regulates IL-12p40 expression by acting on the repressor site GA-12 (GATA sequence in IL-12 promoter). Prostamide E(2) (prostaglandin E(2) ethanolamide), a product considered to be a putative metabolite of AEA by COX-2 (cyclo-oxygenase 2) oxygenation, was also able to inhibit the activity of the IL-12p40 promoter by acting at the repressor site. The effects of AEA and prostamide E(2) on p40 transcription were partially reversed by an antagonist of EP(2) (prostanoid receptor-type 2), suggesting the possibility that prostamide E(2) may contribute to the effects of AEA on IL-12p40 gene regulation. Accordingly, the inhibition of COX-2 by NS-398 partially reversed the inhibitory effects of AEA on IL-12 p40. Overall, our findings provide new mechanistic insights into the activities of AEA in immune-related disorders, which may be relevant for the clinical management of such diseases.

IL-23 P19 Expression Induced by IL-17 and IL-1β in Rheumatoid Arthritis Synovial Mononuclear Cells

Interleukin-23 (IL-23) is a novel pro-inflammatory cytokine which has been implicated to play a pathogenic role in rheumatoid arthritis (RA). This study was undertaken to investigate the IL-23 inductive activity of the proinflammatory cytokine IL-17, IL-1β and tumor necrosis factor (TNF-α) in RA synovial fluid mononuclear cells (SFMC). Expression of IL-23p19, IL-17, IL-1β and TNF-α in joint was examined by immunohistochemistry (IHC) of patients with RA and osteoarthritis (OA). The effects of IL-17 and IL-1β on expression of IL-23p19 in human SFMC from RA patients were determined by reverse transcriptase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). IL-23p19 was expressed in the RA fibroblast like synoviocyte (FLS), but not from OA FLS. Similar to the protein expression, IL-23p19 mRNA could be detected by RT-PCR in RA SFMC. IL-17 and IL-1β could induce RA SFMC to produce the IL-23p19. The effects of IL-17 were much stronger than IL-1β or TNF-α. These responses were observed in a doseresponsive manner. In addition, IL-17 or IL-1β neutralizing antibody down-regulated the expression of IL-23p19 induced by LPS in RA-SFMC. Our results demonstrate that IL-23p19 is overexpressed in RA synovium and IL-17 and IL-1β appears to upregulate the expression of IL-23p19 in RA-SFMC.

Tombus 바이러스의 RNAi Suppressor p19 유전자에 의한 Chlamydomonas reinhardtii의 형질전환

클라미도모나스 (Chlamydomonas reinhardtii)에서 Tombus 바이러스의 p19 유전자가 RNAi suppressor로서 기능하는 지는 조사하기 위하여 형질전환을 수행하였다. Southern분석을 통하여 p19 유전자가 1 copy에서 여러 copy로 도입된 형질전환체를 선발하였다. MAA7 유전자의 3'UTR 부위의 inverted repeat (IR) DNA가 형질전환되어 제작된 #33 strain을 p19유전자로 다시 형질전환 한 결과, MAA7 mRNA의 발현 양이 변하여 일정하지 않고 교란되었으며, 5-FI가 첨가된 배지에서 증식이 저해되었다. 증식이 저해된 것은 p19 유전자에 의한 silencing의 suppression이 일어난 것으로 간주할 수 있다. 그러나 MAA7 mRNA의 발현양이 전반적으로 증가하지 않고 발현양의 교란이 일어났으므로 p19 유전자에 의한 silencing의 suppression으로 보기 어렵다. 따라서 본 연구에 사용된 p19 유전자가 클라미도모나스에서는 codon usage가 상이하여 단백질 발현양이 충분치 않아서 silencing의 suppression을 완전하게 하지 못하거나 고등식물에서 일어나는 방식과는 다른 방식으로 suppression한다고 할 수 있다. Chlamydomonas reinhardtii was transformed with the coding sequence of the Tombus virus gene p19 to determine whether the gene functions as an RNAi suppressor in C. reinhardtii. Transformants were confirmed to have 1 to several copies of p19 gene in their chromosomes. When an RNAi strain of C. reinhardtii generated by transforming the inverted repeat (IR) sequence homologous to the 3'UTR region of the MAA7 gene was re-transformed with the gene p19, MAA7 transcript levels of transformants fluctuated and proliferation of trans-formants on the medium containing 5-FI was suppressed. Overall results suggest that p19-mediated silencing suppression works at a low level in C. reinhardtii because of difference in codon usage resulting in weak P19 expression unless p19-mediated silencing suppression in C. reinhardtii works in a different manner from higher plants.

Cutting Edge: A Key Pathogenic Role of IL-27 in T Cell- Mediated Hepatitis

The signals driving T cell activation in T cell-mediated fulminant hepatitis are not fully understood. In this study, we identify the cytokine IL-27p28/EBI3 as a major pathogenic factor in the ConA model of T cell-mediated hepatitis. We found an up-regulation of hepatic EBI3 and p28 expression and augmented levels of IL-27 in wild-type mice after ConA administration, suggesting a potential pathogenic role of this cytokine in ConA hepatitis. Consistently, IL-27 EBI3-deficient mice were almost completely protected from ConA-induced liver damage. Such protection was associated with reduced levels of IFN-gamma and its signaling proteins pSTAT-1 and T-bet. Finally, in vivo blockade of IL-27 function using a soluble IL-27 receptor fusion protein led to reduced pSTAT1 levels and suppression of liver injury. Taken together, these data demonstrate a key pathogenic role of IL-27 in T cell-mediated liver injury. Furthermore, in vivo blockade of IL-27 emerges as a novel potential therapy for T cell-mediated hepatitis.

EARLY VERSUS LATE ONSET OF MULTIPLE ORGAN FAILURE IS ASSOCIATED WITH DIFFERING PATTERNS OF PLASMA CYTOKINE BIOMARKER EXPRESSION AND OUTCOME AFTER SEVERE TRAUMA

Although multiple organ failure (MOF) remains the leading cause of death after trauma, the pathogenic cellular and molecular mechanisms underlying MOF are poorly understood. In addition to proinflammatory and anti-inflammatory mediator cascades, the temporal onset of MOF has generated recent interest because the organ systems involved into MOF seem to deteriorate in a time-dependent fashion after trauma. We therefore investigated the temporal course of MOF in traumatized human patients and evaluated and compared the distribution patterns of cytokine expression, including interleukin (IL) 6, IL-8, IL-10, and the soluble tumor necrosis factor-[alpha] receptors sTNF-R p55 and sTNF-R p75 in early-onset versus late-onset MOF. In addition, we analyzed the predictive value of cytokine biomarkers of MOF and lethal outcome. In a prospective observational cohort study conducted at three trauma centers, all patients (n = 352) admitted to two level 1 trauma centers in Germany were enrolled in the study based on the following inclusion criteria: severe traumatic brain injury (TBI) with a Glasgow Coma Scale (GCS) score of 8 or lower and/or distinct changes in cranial computed tomography and/or multiple injuries (MT) to the body (at least two regions had Abbreviated Injury Scale score of 3 or higher). The incidence of MOF was evaluated using the modified Goris-MOF score. The temporal onset of MOF was divided into early-onset MOF (EMOF, developing on days 0-3), late-onset MOF (LMOF, developing on days 4-10), combined early-onset and late-onset MOF (CMOF), and patients never showing signs of MOF during the observation period. In addition, the levels of the serum cytokine markers IL-6, IL-8, IL-10, sTNF-R p55, and sTNF-R p75 were analyzed at specific posttraumatic time points using established enzyme-linked immunosorbent assay techniques. A total of 352 patients (274 men and 78 women; TBI, 101; TBI + MT, 125; MT, 126) were enrolled into the study. Patients assigned to the EMOF group showed specific disruption of pulmonary and cardiocirculatory function, whereas LMOF was significantly associated with hepatic failure. The patients without signs of MOF and the EMOF patients had the same risk of lethal outcome (8.2% vs. 7.5%); LMOF and CMOF were found to be associated with a 3- to 4-fold increase in mortality (38.5% vs. 30.6%, respectively). Analysis of cytokine serum biomarkers revealed that patients with LMOF showed a biphasic elevation of IL-6 and significantly higher sTNF-R concentrations than did all other subgroups (P < 0.001). In addition, the initial values (days 0-1) of sTNF-R p55 and sTNF-R p75 expression levels had a good predictive capacity for the development of LMOF (p55, 0.75; p75, 0.72); values greater than 0.65 were accepted to have a predictive capacity. These results demonstrate that mortality differs significantly between the development of EMOF and LMOF after traumatic injury. Our results also suggest that serum cytokine measurements may be important early biochemical markers for predicting the development of delayed MOF.

A Proximal κB Site in the IL-23 p19 Promoter Is Responsible for RelA- and c-Rel-Dependent Transcription

IL-23 is a heterodimeric cytokine composed of a unique p19 subunit and a common p40 subunit is shared with IL-12. IL-23 promotes the inflammatory response by inducing the expansion of CD4(+) cells producing IL-17. The regulation of p19 gene expression has been less studied than that of p40 subunit expression, which in macrophages is well known to be dependent on NF-kappaB. To clarify the role of NF-kappaB in expression of the p19 gene, we analyzed mRNA levels in NF-kappaB-deficient macrophages. As reported to occur in dendritic cells, p19 expression was dramatically reduced in c-rel-deficient macrophages. Moreover, we found that p19 expression was halved in rela-deficient macrophages, but it was enhanced in p52-deficient macrophages. The p19 promoter contains three putative kappaB sites, located at nt -642 to -632 (kappaB-642), nt -513 to -503 (kappaB-513), and nt -105 to -96 (kappaB-105), between the transcription start site and -937 bp upstream in the p19 promoter region. Although EMSA analysis indicated that both kappaB-105 and kappaB-642, but not kappaB-513, bound to NF-kappaB in vitro, luciferase-based reporter assays showed that the most proximal kappaB site, kappaB-105, was uniquely indispensable to the induction of p19 transcription. Chromatin immunoprecipitation demonstrated in vivo association of RelA, c-Rel, and p50 with kappaB-105 of the p19 promoter. These results provide the evidence that the association of RelA and c-Rel with the proximal kappaB site in the p19 promoter is required to induce of p19 expression.

Inducible IL-23p19 expression in human microglia via p38 MAPK and NF-κB signal pathways

Activated microglia can release a variety of proinflammatory cytokines that play a crucial role in the pathogenesis of multiple sclerosis (MS). IL-23, a novel proinflammatory cytokine, is required for the induction of experimental autoimmune encephalomyelitis. Previously we demonstrated that IL-23 is expressed in MS lesions and that microglia are one cellular source of IL-23 in MS patients. In the present study we investigated the inducible expression and regulation of p19, a key subunit of IL-23, in human microglia. We demonstrated the inducible expression of IL-23p19 by lipopolysaccharide-stimulated microglial cells. Using signaling pathway-specific inhibitors, we showed that blocking p38 MAP kinase or NF-κB signaling pathway significantly reduced p19 expression in microglia. The regulatory role of p38 MAP kinase in p19 expression was further confirmed by decreased expression in microglia transduced with dominant-negative p38. We concluded that the p38 MAP kinase and NF-κB signaling pathways play an important role in regulation of IL-23p19 expression on human microglia, and are thus potential therapeutic targets in the treatment of MS.

FOXO transcription factor-dependent p15INK4b and p19INK4d expression

FOXO (Forkhead box O) transcription factors are involved in cell-cycle arrest or apoptosis induction by transcripting cell-cycle inhibitor p27(KIP1) or apoptosis-related genes, respectively. Akt/protein kinase B promotes cell proliferation and suppresses apoptosis, in part, by phosphorylating FOXOs. Phosphorylated FOXOs could not exhibit transcriptional activity because of their nuclear export. Here we show that p15(INK4b) and p19(INK4d) transcription is associated with FOXO-mediated G1 cell-cycle arrest. Inhibition of Akt signaling by PI3K inhibitors, a PDK1 inhibitor, or dominant-negative Akt transfection increased expression of p15(INK4b) and p19(INK4d) but not p16(INK4a) and p18(INK4c). Ectopic expression of wild type or active FOXO but not inactive form also increased p15(INK4b) and p19(INK4d) levels. FOXOs bound to promoter regions and induced transcription of these genes. No increase in the G1-arrested cell population, mediated by PI3K inhibitor LY294002, was observed in INK4b-/- or INK4d-/- murine embryonic fibroblasts. In summary, FOXOs are involved in G1 arrest caused by Akt inactivation via p15(INK4b) and p19(INK4d) transcription.

IFN-α regulates Toll-like receptor-mediated IL-27 gene expression in human macrophages

IL-27 is a novel member of the IL-12 cytokine family. IL-27 has pro- and anti-inflammatory properties, and it controls the responses of adaptive immunity. It promotes the differentiation of naïve Th cells and suppresses the effector functions of Th17 cells. Biologically active IL-27 is a heterodimer composed of EBV-induced gene 3 (EBI3) and p28 proteins. We report that TLR-dependent expression of IL-27 in human macrophages is mediated by IFN-alpha. Stimulation of macrophages with agonists for TLR3 {polyinosinic:polycytidylic acid [poly(I:C)]}, TLR4 (LPS), or TLR7/8 (R848) results in concurrent expression of EBI3 and p28. The p28 expression is inhibited with neutralizing anti-IFN-alpha antibodies. Unlike poly(I:C), LPS, and R848, TLR2 agonist (S)-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-N-palmitoyl-(R)-Cys-(S)-Ser(S)-Lys4-OH trihydrochloride does not stimulate macrophages to produce IFN-alpha, and therefore, it is not able to turn on the expression of p28. There is an IFN-stimulated response element (ISRE) in the p28 gene promoter. IFN-alpha enhances the expression of IFN regulatory factor 1 (IRF-1) in macrophages and induces binding of IRF-1 to the p28 ISRE site. The data provide a mechanistic basis for the IFN-alpha-mediated activation of IL-27. The data emphasize a role of IFN-alpha in immune responses, which rely on the recognition of pathogens by TLRs.

Peroxisome proliferator‐activated receptor‐α agonist fenofibrate regulates IL‐12 family cytokine expression in the CNS: relevance to multiple sclerosis

The interleukin-12 (IL-12) family of cytokines which includes IL-12, IL-23, and IL-27 play critical roles in T cell differentiation and are important modulators of multiple sclerosis and experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Previously, we demonstrated that peroxisome proliferator-activated receptor (PPAR) -alpha agonists suppress the development of EAE. The present studies demonstrated that the PPAR-alpha agonist fenofibrate inhibited the secretion of IL-12p40, IL-12p70 (p35/p40), IL-23 (p19/p40), and IL-27p28 by lipopolysaccharide-stimulated microglia. The cytokines interferon-gamma and tumor necrosis factor-alpha also stimulated IL-12 p40 and IL-27 p28 expression by microglia, which was suppressed by fenofibrate. Furthermore, fenofibrate inhibited microglial expression of CD14 which plays a critical role in TLR signaling, suggesting a mechanism by which this PPAR-alpha agonist regulates the production of these pro-inflammatory molecules. In addition, fenofibrate suppressed the secretion of IL-12p40, IL-23, and IL-27p28 by lipopolysaccharide-stimulated astrocytes. Importantly, fenofibrate suppression of EAE was associated with decreased expression of IL-12 family cytokine mRNAs as well as mRNAs encoding TLR4, CD14, and MyD88 known to play critical roles in MyD88-dependent TLR signaling. These novel observations suggest that PPAR-alpha agonists including fenofibrate may modulate the development of EAE, at least in part, by suppressing the production of IL-12 family cytokines and MyD88-dependent signaling.

Human T-lymphotropic virus type-1 p30 alters cell cycle G2 regulation of T lymphocytes to enhance cell survival

BackgroundHuman T-lymphotropic virus type-1 (HTLV-1) causes adult T-cell leukemia/lymphoma and is linked to a number of lymphocyte-mediated disorders. HTLV-1 contains both regulatory and accessory genes in four pX open reading frames. pX ORF-II encodes two proteins, p13 and p30, whose roles are still being defined in the virus life cycle and in HTLV-1 virus-host cell interactions. Proviral clones of HTLV-1 with pX ORF-II mutations diminish the ability of the virus to maintain viral loads in vivo. p30 expressed exogenously differentially modulates CREB and Tax-responsive element-mediated transcription through its interaction with CREB-binding protein/p300 and while acting as a repressor of many genes including Tax, in part by blocking tax/rex RNA nuclear export, selectively enhances key gene pathways involved in T-cell signaling/activation.ResultsHerein, we analyzed the role of p30 in cell cycle regulation. Jurkat T-cells transduced with a p30 expressing lentivirus vector accumulated in the G2-M phase of cell cycle. We then analyzed key proteins involved in G2-M checkpoint activation. p30 expression in Jurkat T-cells resulted in an increase in phosphorylation at serine 216 of nuclear cell division cycle 25C (Cdc25C), had enhanced checkpoint kinase 1 (Chk1) serine 345 phosphorylation, reduced expression of polo-like kinase 1 (PLK1), diminished phosphorylation of PLK1 at tyrosine 210 and reduced phosphorylation of Cdc25C at serine 198. Finally, primary human lymphocyte derived cell lines immortalized by a HTLV-1 proviral clone defective in p30 expression were more susceptible to camptothecin induced apoptosis. Collectively these data are consistent with a cell survival role of p30 against genotoxic insults to HTLV-1 infected lymphocytes.ConclusionCollectively, our data are the first to indicate that HTLV-1 p30 expression results in activation of the G2-M cell cycle checkpoint, events that would promote early viral spread and T-cell survival.

T‐box factors: targeting to chromatin and interaction with the histone H3 N‐terminal tail

T-box transcription factors play a crucial role in development where they are implicated in patterning and cell fate decisions. Tbx2 and Tbx3 have also been implicated in several cancers including melanoma, and can act as antisenescence factors through their ability to repress p19(ARF) and p21(CIP1) expression. Although several target genes for T-box factors have been identified, it is unknown whether this family of proteins can bind chromatin, a property that would facilitate the epigenetic reprogramming that occurs in both development and cancer progression. Here, we show that Tbx2 has the potential to recognize mitotic chromatin in a DNA-dependent fashion, can interact specifically with the histone H3 N-terminal tail, a property shared with Tbx4, Tbx5 and Tbx6, and can also recognize nucleosomal DNA, with binding to nucleosomes being antagonized by the presence of the histone tails. Strikingly, in vivo Tbx2 co-localization with pericentric heterochromatin appears to be regulated and ectopic expression of Tbx2 leads to severe mitotic defects. Taken together our results suggest that Tbx2, and most likely other members of the T-box family, are able to target chromatin and may indicate a role for the T-box factors in epigenetic reprogramming events.

Dysregulated expression of interleukin-23 and interleukin-12 subunits in systemic lupus erythematosus patients

The aim of this study was to investigate the regulation of interleukin (IL)-12 and IL-23 expression in the autoimmune disease, systemic lupus erythematosus (SLE). mRNA from healthy subjects and SLE patients were prepared from peripheral blood mononuclear cells (PBMC) and quantitative real-time polymerase chain reaction was performed to quantify IL-23 specific subunit P19, IL-12 specific subunit P35, and their common subunit P40. IL-12 specific subunit P35 mRNA expression in untreated and treated SLE patients was significantly lower than healthy controls (P = 0.015 and 0.000, respectively). Compared with untreated SLE patients, treatment of SLE patients with corticosteroids or corticosteroids plus another immunosuppressor significantly suppressed P40 and P19 expression (P = 0.002 and 0.015, respectively). The mRNA levels of p19, p40, and p35 in active SLE patients (SLEDAT > 10) were significantly higher compared with those in the inactive SLE patients (SLEDAI <or= 10) (P = 0.000, 0.000, and 0.017, respectively). These results suggest that deficiency of IL-12 and possibly upregulation of IL-23 may contribute to SLE pathogenesis and both cytokines may be therapeutic targets in SLE.

Dysregulated expression of interleukin-23 and interleukin-12 subunits in systemic lupus erythematosus patients

The aim of this study was to investigate the regulation of interleukin (IL)-12 and IL-23 expression in the autoimmune disease, systemic lupus erythematosus (SLE). mRNA from healthy subjects and SLE patients were prepared from peripheral blood mononuclear cells (PBMC) and quantitative real-time polymerase chain reaction was performed to quantify IL-23 specific subunit P19, IL-12 specific subunit P35, and their common subunit P40. IL-12 specific subunit P35 mRNA expression in untreated and treated SLE patients was significantly lower than healthy controls (P = 0.015 and 0.000, respectively). Compared with untreated SLE patients, treatment of SLE patients with corticosteroids or corticosteroids plus another immunosuppressor significantly suppressed P40 and P19 expression (P = 0.002 and 0.015, respectively). The mRNA levels of p19, p40, and p35 in active SLE patients (SLEDAT > 10) were significantly higher compared with those in the inactive SLE patients (SLEDAI ≤ 10) (P = 0.000, 0.000, and 0.017, respectively). These results suggest that deficiency of IL-12 and possibly upregulation of IL-23 may contribute to SLE pathogenesis and both cytokines may be therapeutic targets in SLE.

Interleukin (IL)-23 p19 expression induced by IL-1 in human fibroblast-like synoviocytes with rheumatoid arthritis via active nuclear factor- B and AP-1 dependent pathway

To explore the source of the p19 subunit of interleukin-23 (IL-23) in joints with rheumatoid arthritis (RA), the effects of IL-1beta and tumour necrosis factor (TNF)-alpha on IL-23 gene expression in RA fibroblast-like synoviocytes and the effect of IL-23 on proinflammatory cytokines. Expression of IL-23 p19 in joints was examined by immunohistochemical analysis of patients with RA and osteoarthritis (OA). The effects of IL-1beta and TNF-alpha on the expression, of IL-23 p19 and IL-12 p35 subunits in human fibroblast-like synoviocytes from RA patients (HFLS-RA) were determined by reverse transcriptase polymerase chain reaction (RT-PCR), quantitative PCR and western blotting assay. Blockade of nuclear factor kappaB (NF-kappaB) or AP-1 activation was used to verify the involvement of intracellular signal pathways of the induction of p19. IL-23-induced IL-8 and IL-6 productions were determined in HFLS-RA by RT-PCR and enzyme-linked immunosorbent assay. IL-23 p19 was expressed in the synovium from RA, but not from OA patients. Similar to the protein expression, IL-23 p19 mRNA could be detected by RT-PCR in four of five RA synovial fluid mononuclear cells (SFMC). IL-1beta and TNF-alpha could induce RA fibroblast-like synoviocytes to produce the IL-23 p19 subunit. The effects of IL-1beta were much stronger than TNF-alpha. These responses were observed in both a dose-responsive and time-dependent manner. IL-1beta produced weakly enhanced gene expression of the p35 subunits of IL-12. IL-1beta also promotes the p35 expression, a subunit of IL-12, but weakly. In addition, the NF-kappaB and the AP-1 inhibitors down-regulated the expression of IL-23 p19 mRNA induced by IL-1beta. IL-23 receptor (IL-23R) was of constitutive expression in HFLS-RA. Moreover, IL-23 up-regulated the IL-8 and IL-6 mRNA and protein levels in a dose-dependent manner in HFLS-RA. Our results demonstrate that IL-23, produced by mononuclear cells in synovial fluid with RA and HFLS-RA, promotes inflammatory responses in RA by inducing IL-8 and IL-6 production from HFLS. IL-1beta regulates IL-23 p19 expression via NF-kappaB and AP-1 pathways. This report also demonstrates that IL-23 could promote inflammatory responses in HFLS-RA by stimulating IL-8 and IL-6 production.