Systemic lupus erythematosus (SLE) is an autoimmune disease that predominantly affects women of childbearing age. Although sex hormones have been implicated in gender bias of the development of this disease, molecular mechanisms remain largely unknown. Elucidation of the role of SLE susceptibility genes, expression of which is regulated by sex hormones, is important to understand the development of the disease. Characterization of the B6.Nba2 lupus prone congenic mice and functional analysis has revealed a previously unknown role for the interferon (IFN)-activatable Ifi202 gene in SLE susceptibility. The major objectives of the proposed studies are to understand the gender-specific increased expression of Ifi202 gene in certain lupus prone strains of mice and to define the role of the encoded phosphoprotein, p202, in the development of lupus susceptibility. The protein p202 (52-kDa) is an inducible (inducible by type-I IFN and interleukin-6) transcriptional modulator with demonstrated ability to inhibit cell cycle progression and apoptosis. Based on our preliminary and other observations, we hypothesize that gender-specific and genetic factors contribute to increased expression of p202 in certain lupus-prone strains of mice. Moreover, we postulate that p202 contributes to lupus susceptibility by increasing the threshold for apoptosis in B and T cells by inhibiting the transcriptional activity of proapoptotic factors, such as E2F and p53.
Aim #1 : To determine how gender-specific and genetic factors contribute to increased expression of p202. We will compare expression of Ifi202 mRNA and protein between age-matched male and female mice (B6, NZB, and B6.Nba2 strains of mice), male and ovariectomized female mice, and estrogen or placebo treated orchiectomized male and female mice. Additionally, we will determine (i) how estrogen (E2) levels through estrogen receptor activate the transcription of the Ifi202; (ii) whether E2-mediated posttranscriptional mechanisms, such as Ifi202 mRNA and protein stabilization, contribute to up-regulation of p202; and (iii) whether nucleocytoplasmic distribution of p202 and its phosphorylation depend on the gender, levels of type-I interferons (alpha and beta), or interleukin-6.
Aim #2 : To investigate whether increased levels of p202 in splenocytes (from male and female mice) correlate with inhibition of the transcriptional activity of E2Fs (E2F1 and E2F2), down-regulation of the expression of the E2F target genes, and defects in activation-induced cell death of CD4+ T cells.
Aim #3 : To elucidate the molecular mechanisms by which increased expression of p202 in splenocytes (from male and female mice) inhibits p53-mediated transcriptional activation and repression of genes, and p53-mediated apoptosis. Significance: Our studies will identify molecular mechanisms by which gender-specific increased expression of p202 in cells of the immune system contributes to lupus susceptibility in a mouse model of lupus.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI066261-02
Application #
7068073
Study Section
Hypersensitivity, Autoimmune, and Immune-mediated Diseases Study Section (HAI)
Program Officer
Johnson, David R
Project Start
2005-06-01
Project End
2007-02-28
Budget Start
2006-03-01
Budget End
2007-02-28
Support Year
2
Fiscal Year
2006
Total Cost
$290,021
Indirect Cost
Name
Loyola University Chicago
Department
Radiation-Diagnostic/Oncology
Type
Schools of Medicine
DUNS #
791277940
City
Maywood
State
IL
Country
United States
Zip Code
60153
Panchanathan, Ravichandran; Liu, Hongzhu; Leung, Yuet-Kin et al. (2015) Bisphenol A (BPA) stimulates the interferon signaling and activates the inflammasome activity in myeloid cells. Mol Cell Endocrinol 415:45-55
Hughes, Grant C; Choubey, Divaker (2014) Modulation of autoimmune rheumatic diseases by oestrogen and progesterone. Nat Rev Rheumatol 10:740-51
Panchanathan, Ravichandran; Liu, Hongzhu; Choubey, Divaker (2013) Expression of murine Unc93b1 is up-regulated by interferon and estrogen signaling: implications for sex bias in the development of autoimmunity. Int Immunol 25:521-9
Panchanathan, Ravichandran; Choubey, Divaker (2013) Murine BAFF expression is up-regulated by estrogen and interferons: implications for sex bias in the development of autoimmunity. Mol Immunol 53:15-23
Veeranki, Sudhakar; Choubey, Divaker (2012) Interferon-inducible p200-family protein IFI16, an innate immune sensor for cytosolic and nuclear double-stranded DNA: regulation of subcellular localization. Mol Immunol 49:567-71
Choubey, Divaker (2012) Interferon-inducible Ifi200-family genes as modifiers of lupus susceptibility. Immunol Lett 147:10-7
Choubey, Divaker (2012) DNA-responsive inflammasomes and their regulators in autoimmunity. Clin Immunol 142:223-31
Panchanathan, Ravichandran; Liu, Hongzhu; Liu, Hongqi et al. (2012) Distinct regulation of murine lupus susceptibility genes by the IRF5/Blimp-1 axis. J Immunol 188:270-8
Moudgil, Kamal D; Choubey, Divaker (2011) Cytokines in autoimmunity: role in induction, regulation, and treatment. J Interferon Cytokine Res 31:695-703
Panchanathan, Ravichandran; Duan, Xin; Arumugam, Muthuvel et al. (2011) Cell type and gender-dependent differential regulation of the p202 and Aim2 proteins: implications for the regulation of innate immune responses in SLE. Mol Immunol 49:273-80

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