scholarly journals Expression of the retinoblastoma protein RbAp48 in exocrine glands leads to Sjögren's syndrome–like autoimmune exocrinopathy

2008 ◽  
Vol 205 (12) ◽  
pp. 2915-2927 ◽  
Author(s):  
Naozumi Ishimaru ◽  
Rieko Arakaki ◽  
Satoko Yoshida ◽  
Akiko Yamada ◽  
Sumihare Noji ◽  
...  

Although several autoimmune diseases are known to develop in postmenopausal women, the mechanisms by which estrogen deficiency influences autoimmunity remain unclear. Recently, we found that retinoblastoma-associated protein 48 (RbAp48) induces tissue-specific apoptosis in the exocrine glands depending on the level of estrogen deficiency. In this study, we report that transgenic (Tg) expression of RbAp48 resulted in the development of autoimmune exocrinopathy resembling Sjögren's syndrome. CD4+ T cell–mediated autoimmune lesions were aggravated with age, in association with autoantibody productions. Surprisingly, we obtained evidence that salivary and lacrimal epithelial cells can produce interferon-γ (IFN-γ) in addition to interleukin-18, which activates IFN regulatory factor-1 and class II transactivator. Indeed, autoimmune lesions in Rag2−/− mice were induced by the adoptive transfer of lymph node T cells from RbAp48-Tg mice. These results indicate a novel immunocompetent role of epithelial cells that can produce IFN-γ, resulting in loss of local tolerance before developing gender-based autoimmunity.

2006 ◽  
Vol 26 (8) ◽  
pp. 2924-2935 ◽  
Author(s):  
Naozumi Ishimaru ◽  
Rieko Arakaki ◽  
Fumie Omotehara ◽  
Koichi Yamada ◽  
Kenji Mishima ◽  
...  

ABSTRACT Although tissue-specific apoptosis in the exocrine glands in estrogen-deficient mice may contribute to the development of autoimmune exocrinopathy, the molecular mechanism responsible for tissue-specific apoptosis remains obscure. Here we show that RbAp48 overexpression induces p53-mediated apoptosis in the exocrine glands caused by estrogen deficiency. RbAp48-inducible transfectant results in rapid apoptosis with p53 phosphorylation (Ser9) and α-fodrin cleavage. Reducing the expression of RbAp48 through small interfering RNA inhibits the apoptosis. Prominent RbAp48 expression with apoptosis was observed in the exocrine glands of C57BL/6 ovariectomized (OVX) mice but not in OVX estrogen receptor α−/−, p53−/−, and E2F-1−/− mice. Indeed, transgenic expression of the RbAp48 gene induced apoptosis in the exocrine glands but not in other organs. These findings indicate that estrogen deficiency initiates p53-mediated apoptosis in the exocrine gland cells through RbAp48 overexpression and exerts a possible gender-based risk of autoimmune exocrinopathy in postmenopausal women.


2003 ◽  
Vol 284 (5) ◽  
pp. C1133-C1139 ◽  
Author(s):  
Pertteli Salmenperä ◽  
Sammy Hämäläinen ◽  
Mika Hukkanen ◽  
Esko Kankuri

We investigated the role of IFN-γ and MAPKs on the expression and activity of the transcription factor CCAAT/enhancer-binding protein-beta (C/EBPβ) in the T84 colon epithelial cell line. IFN-γ induced the expression and activity of C/EBPβ and subsequently increased the secretion of IL-6 from these cells. Treatment with the p38 inhibitor SB-203580, the MEK1 and MEK2 inhibitor U-0126, or the translational inhibitor cycloheximide inhibited the induction of C/EBPβ and IL-6 by IFN-γ, whereas the MEK1 inhibitor PD-98059 or the tyrosine kinase inhibitor genistein had no effect. These results suggest a role for MEK2 and p38 in IFN-γ-mediated signal transduction and induction of C/EBPβ expression and activity associated with interleukin-6 (IL-6) secretion in colon epithelial cells.


Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 757
Author(s):  
Sandra Barroso-Arévalo ◽  
Jose A. Barasona ◽  
Estefanía Cadenas-Fernández ◽  
José M. Sánchez-Vizcaíno

African swine fever virus (ASFv) is one of the most challenging pathogens to affect both domestic and wild pigs. The disease has now spread to Europe and Asia, causing great damage to the pig industry. Although no commercial vaccine with which to control the disease is, as yet, available, some potential vaccine candidates have shown good results in terms of protection. However, little is known about the host immune mechanisms underlying that protection, especially in wild boar, which is the main reservoir of the disease in Europe. Here, we study the role played by two cytokines (IL-10 and IFN-γ) in wild boar orally inoculated with the attenuated vaccine candidate Lv17/WB/Rie1 and challenged with a virulent ASFv genotype II isolate. A group of naïve wild boar challenged with the latter isolate was also established as a control group. Our results showed that both cytokines play a key role in protecting the host against the challenge virus. While high levels of IL-10 in serum may trigger an immune system malfunctioning in challenged animals, the provision of stable levels of this cytokine over time may help to control the disease. This, together with high and timely induction of IFN-γ by the vaccine candidate, could help protect animals from fatal outcomes. Further studies should be conducted in order to support these preliminary results and confirm the role of these two cytokines as potential markers of the evolution of ASFV infection.


2006 ◽  
Vol 290 (5) ◽  
pp. F1234-F1240 ◽  
Author(s):  
Myrto Giannopoulou ◽  
Steven C. Iszkula ◽  
Chunsun Dai ◽  
Xiaoyue Tan ◽  
Junwei Yang ◽  
...  

Interferon-γ (IFN-γ) is a multifunctional cytokine that elicits antifibrotic activity in a variety of organs. In this study, we investigated the potential role and mechanism of IFN-γ in modulating the fibrogenic action of transforming growth factor (TGF)-β1 in tubular epithelial cells. Incubation of human proximal tubular epithelial (HKC) cells with IFN-γ inhibited TGF-β1-mediated α-smooth muscle actin (α-SMA) expression. IFN-γ also abolished TGF-β1-induced fibronectin and plasminogen activator inhibitor-1 (PAI-1) expression. To explore the mechanisms by which INF-γ inhibits TGF-β1 action, the signaling pathways that are critical for mediating the antifibrotic activity of IFN-γ were studied. Stimulation of HKC cells with IFN-γ triggered a sustained activation of Erk-1/2 and signal transducer and activator of transcription-3 (Stat3). Blockade of Erk-1/2 activation with an Mek1 inhibitor abolished the inhibitory effect of IFN-γ on α-SMA expression, whereas inhibition of Stat3 activation had no influence. Constitutive activation of Erk-1/2 by ectopic expression of activated Mek1 mimicked IFN-γ and suppressed TGF-β1-mediated α-SMA expression. Interestingly, inhibition of Stat3 activation abolished the ability of IFN-γ to attenuate TGF-β1-mediated PAI-1 and fibronectin expression in HKC cells. These findings indicate that IFN-γ is capable of antagonizing the fibrogenic actions of TGF-β1 in renal tubular epithelial cells. The antifibrotic action of IFN-γ appears to be mediated through a coordinated activation of both Erk-1/2 and Stat3 signal pathways in a mutually independent fashion.


2000 ◽  
Vol 279 (5) ◽  
pp. G1094-G1103 ◽  
Author(s):  
Derek M. McKay ◽  
Fernando Botelho ◽  
Peter J. M. Ceponis ◽  
Carl D. Richards

Signal transducers and activators of transcription (STATs) are critical intracellular signaling molecules for many cytokines. We compared the ability of T84 epithelial cells to activate STATs in response to cytokines [interferon-γ (IFN-γ), interleukin (IL)-4, IL-10, and tumor necrosis factor-α (10 ng/ml)] and conditioned medium from superantigen [ Staphylococcus aureus enterotoxin B (SEB)]-activated peripheral blood mononuclear cells (PBMC) using electrophoretic mobility shift assays (EMSA). Of the cytokines tested, only IFN-γ caused a STAT-1 response. Exposure to SEB-PBMC-conditioned medium resulted in STAT-1 or STAT-1/3 activation, and inclusion of anti-IFN-γ antibodies in the conditioned medium abolished the STAT-1 signal. Cells treated with transcription factor decoys, DNA oligonucleotides bearing the STAT-1 recognition motif, and then SEB-PBMC-conditioned medium displayed a reduced STAT-1 signal on EMSA, yet this treatment did not prevent the drop in transepithelial resistance (measured in Ussing chambers) caused by SEB-PBMC-conditioned medium. In contrast, the phosphatidylinositol 3′-kinase (PI 3-K) inhibitor LY-294002 significantly reduced the drop in transepithelial resistance caused by SEB-PBMC-conditioned medium. Thus data are presented showing STAT-1 (±STAT-3) and PI 3-K activation in epithelial cells in response to immune mediators released by superantigen immune activation. Although the involvement of STAT-1/-3 in the control of barrier function remains a possibility, PI-3K has been identified as a regulator of T84 paracellular permeability.


2020 ◽  
Vol 34 ◽  
pp. 205873842092944
Author(s):  
Chieh-Shan Wu ◽  
Shih-Chao Lin ◽  
Shiming Li ◽  
Yu-Chih Chiang ◽  
Nicole Bracci ◽  
...  

Atopic dermatitis (AD) is a chronic inflammatory disease of the skin that substantially affects a patient’s quality of life. While steroids are the most common therapy used to temporally alleviate the symptoms of AD, effective and nontoxic alternatives are urgently needed. In this study, we utilized a natural, plant-derived phenolic compound, phloretin, to treat allergic contact dermatitis (ACD) on the dorsal skin of mice. In addition, the effectiveness of phloretin was evaluated using a mouse model of ACD triggered by 2,4-dinitrochlorobenzene (DNCB). In our experimental setting, phloretin was orally administered to BALB/c mice for 21 consecutive days, and then, the lesions were examined histologically. Our data revealed that phloretin reduced the process of epidermal thickening and decreased the infiltration of mast cells into the lesion regions, subsequently reducing the levels of histamine and the pro-inflammatory cytokines interleukin (IL)-6, IL-4, thymic stromal lymphopoietin (TSLP), interferon-γ (IFN-γ) and IL-17A in the serum. These changes were associated with lower serum levels after phloretin treatment. In addition, we observed that the mitogen-activated protein kinase (MAPK) and NF-κB pathways in the dermal tissues of the phloretin-treated rodents were suppressed compared to those in the AD-like skin regions. Furthermore, phloretin appeared to limit the overproliferation of splenocytes in response to DNCB stimulation, reducing the number of IFN-γ-, IL-4-, and IL-17A-producing CD4+ T cells in the spleen back to their normal ranges. Taken together, we discovered a new therapeutic role of phloretin using a mouse model of DNCB-induced ACD, as shown by the alleviated AD-like symptoms and the reversed immunopathological effects. Therefore, we believe that phloretin has the potential to be utilized as an alternative therapeutic agent for treating AD.


2014 ◽  
Vol 95 (3) ◽  
pp. 659-670 ◽  
Author(s):  
Albert Zimmermann ◽  
Sebastian Hauka ◽  
Marco Maywald ◽  
Vu Thuy Khanh Le ◽  
Silvia K. Schmidt ◽  
...  

Despite a rigorous blockade of interferon-γ (IFN-γ) signalling in infected fibroblasts as a mechanism of immune evasion by human cytomegalovirus (HCMV), IFN-γ induced indoleamine-2,3-dioxygenase (IDO) has been proposed to represent the major antiviral restriction factor limiting HCMV replication in epithelial cells. Here we show that HCMV efficiently blocks transcription of IFN-γ-induced IDO mRNA both in infected fibroblasts and epithelial cells even in the presence of a preexisting IFN-induced antiviral state. This interference results in severe suppression of IDO bioactivity in HCMV-infected cells and restoration of vigorous HCMV replication. Depletion of IDO expression nonetheless substantially alleviated the antiviral impact of IFN-γ treatment in both cell types. These findings highlight the effectiveness of this IFN-γ induced effector gene in restricting HCMV productivity, but also the impact of viral counter-measures.


2021 ◽  
Vol 12 ◽  
Author(s):  
Qi Jiang ◽  
Guocan Yang ◽  
Fan Xiao ◽  
Jue Xie ◽  
Shengjun Wang ◽  
...  

Upon antigenic stimulation, naïve CD4+T cells differentiate into different subsets and secrete various cytokines to exert biological effects. Th22 cells, a newly identified CD4+T cell subset,are distinct from the Th1, Th2 and Th17 subsets. Th22 cells secrete certain cytokines such as IL-22, IL-13 and TNF-α, but not others, such as IL-17, IL-4, or interferon-γ (IFN-γ), and they express chemokine receptors CCR4, CCR6 and CCR10. Th22 cells were initially found to play a role in skin inflammatory diseases, but recent studies have demonstrated their involvement in the development of various autoimmune diseases. Here, we review research advances in the origin, characteristics and effector mechanisms of Th22 cells, with an emphasis on the role of Th22 cells and their main effector cytokine IL-22 in the pathogenesis of autoimmune diseases. The findings presented here may facilitate the development of new therapeutic strategies for targeting these diseases.


2007 ◽  
Vol 409 (1) ◽  
pp. 179-185 ◽  
Author(s):  
Sari Vanhatupa ◽  
Daniela Ungureanu ◽  
Maija Paakkunainen ◽  
Olli Silvennoinen

STAT1 (signal transducer and activator of transcription 1) is a critical mediator of IFN-γ (interferon-γ)-induced gene responses, and its function is regulated through phosphorylation of Tyr701 and Ser727. MAPK (mitogen-activated protein kinase) pathways mediate phosphorylation of Ser727 in response to microbial infections, stress stimuli and growth factors. Recently, STAT1 was found to become modified by PIAS (protein inhibitor of activated STAT)-mediated SUMO-1 (small ubiquitin-related modifier-1) conjugation at Lys703, but the regulation of this modification is largely unknown. Here, we have investigated the role of MAPK-induced Ser727 phosphorylation in regulation of STAT1 SUMOylation. Activation of the p38MAPK pathway by upstream activating kinase, MKK6 (MAPK kinase-6) or osmotic stress enhanced the SUMOylation of STAT1, which was counteracted by the p38MAPK inhibitor SB202190 or by dominant-negative p38MAPK. Activation of the ERK1/2 (extracellular-signal-regulated kinase 1/2) pathway by Raf-1 also enhanced Ser727 phosphorylation and SUMOylation of STAT1, and this induction was counteracted by PD98059 inhibitor. Mutation of Ser727 to alanine abolished the p38MAPK-induced SUMOylation. Furthermore, S727D and S727E mutations, which mimic the phosphorylation of Ser727, enhanced the basal SUMOylation of STAT1 and interaction between PIAS1 and STAT1. Taken together, these results identify Ser727 phosphorylation as a regulator of STAT1 SUMOylation and highlight the central role of Ser727 in co-ordination of STAT1 functions in cellular responses.


Blood ◽  
2002 ◽  
Vol 100 (8) ◽  
pp. 2899-2907 ◽  
Author(s):  
Duncan Howie ◽  
Susumo Okamoto ◽  
Svend Rietdijk ◽  
Kareem Clarke ◽  
Ninghai Wang ◽  
...  

CD150 (signaling lymphocyte activation molecule [SLAM]) is a self-ligand cell surface glycoprotein expressed on T cells, B cells, macrophages, and dendritic cells. To further explore the role of CD150 signaling in costimulation and TH1 priming we have generated a panel of rat antimouse CD150 monoclonal antibodies. CD150 cell surface expression is up-regulated with rapid kinetics in activated T cells and lipopolysaccharide/interferon γ (IFN-γ)–activated macrophages. Anti-CD150 triggering induces strong costimulation of T cells triggered through CD3. DNA synthesis of murine T cells induced by anti-CD150 is not dependent on SLAM-associated protein (SAP, SH2D1A), because anti-CD150 induces similar levels of DNA synthesis in SAP−/− T cells. Antibodies to CD150 also enhance IFN-γ production both in wild-type and SAP−/− T cells during primary stimulation. The level of IFN-γ production is higher in SAP−/− T cells than in wild-type T cells. Anti-CD150 antibodies also synergize with interleukin 12 (IL-12) treatment in up-regulation of IL-12 receptor β2 mRNA during TH1 priming, and inhibit primary TH2 polarization in an IFN-γ–dependent fashion. Cross-linking CD150 on CD4 T cells induces rapid serine phosphorylation of Akt/PKB. We speculate that this is an important pathway contributing to CD150-mediated T-cell proliferation.


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