Systemic lupus erythematosus (SLE) occurs nine times more often in females than males. The purpose of this study was to determine the impact of estrogen receptor (ER) null genotypes on disease in lupus prone NZM2410 (NZM) and MRL/lpr mice, as a method to define the role of estrogen receptor signaling in lupus. ER alpha deficient NZM females, but not males, had significantly prolonged survival, reduced proteinuria, renal pathology scores and serum urea nitrogen levels compared to wildtype mice, despite higher serum anti-dsDNA levels. ER alpha deficient MRL/lpr female, but not male, mice also had significantly less proteinuria and renal pathology scores with no effect on autoantibody levels. Deficiency of ER beta had no effect on disease in either strain or sex. Taken together, these data demonstrate a key role for ER alpha, but not ER beta, in the development of lupus like disease, but not autoimmunity, in female NZM and MRL/lpr mice.

IntroductionFanconi anemia (FA) is an autosomal recessive cancer susceptibility disorder characterized by diverse clinical features such as skeletal or skin abnormalities, progressive bone marrow failure, and increased risk of malignancies. 1-5 FA has been reported in diverse ethnic groups, with an estimated heterozygous carrier frequency of 1 in 300, 6 although this estimate may run higher in certain ethnic groups. 7 Early and accurate diagnosis of Fanconi anemia is important, because it profoundly affects patient monitoring and treatment decisions and permits early genetic counseling of family members. Given the striking sensitivity of patients with FA to DNA-damaging agents, [8][9][10][11] timely diagnosis is critical prior to the use of chemotherapy or radiation therapy of these patients in the bone marrow transplant setting. Diagnosis based on clinical manifestations alone can be difficult because 30% to 40% of patients lack developmental malformations or a positive family history. 12,13 Patients previously not known to carry the diagnosis of FA may present with myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) as the initial manifestation of their disease. Patients with acute leukemia have been diagnosed with FA after developing toxicity from their bone marrow transplant conditioning regimen. 14 The currently used diagnostic test for FA relies on the increased chromosomal breakage and radial formation of FA cells in response to diepoxybutane (DEB) compared with cells from healthy control subjects, 15,16 or from patients with other chromosomal instability disorders 17 or genetic syndromes. The DEB test has excellent sensitivity, specificity, and reproducibility, 16 and it is effective in prenatal diagnosis of FA. 18,19 The DEB test is labor intensive and time consuming, however, and does not easily lend itself to broad screening studies. Furthermore, in some cases of Fanconi mosaicism, false-negative results have been reported with DEB screening of patient lymphocytes.Studies of FA proteins have yielded insights into the molecular pathogenesis of FA. Fanconi anemia is a genetically heterogeneous disorder comprised of at least 8 complementation groups. 20,21 The genes corresponding to each of these groups (A, 22 B, 23 C, 24 D1, 23 D2, 21 E, 25 F, 26 and G 27 ) have been cloned. The similar clinical presentation of patients of different subtypes suggests that these genes function in a common pathway. Indeed, interactions between FANCA, FANCC, FANCE, FANCF, and FANCG have been described. [28][29][30][31][32] Activation of the FA protein complex by DNA damage or cell cycle progression results in monoubiquitination of the downstream FANCD2 protein. 33 Monoubiquitination is a newly recognized class of posttranslational protein modification. 34 Following monoubiquitination, FANCD2 localizes to nuclear foci where it colocalizes with other DNA-repair proteins such as BRCA1 (Figure 1). 33 A point mutation of FANCD2 at lysine 561, the site of monoubiquitination, abrogates its ability to correct the mitomy...

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Peroxisome proliferation-activated receptor (PPAR)␥ agonists inhibit inducible nitric-oxide synthase (iNOS), tumor necrosis factor-␣, and interleukin-6. Because of these effects, synthetic PPAR␥ agonists, including thiazolidinediones, are being studied for their impact on inflammatory disease. The anti-inflammatory concentrations of synthetic PPAR␥ agonists range from 10 to 50 M, whereas their binding affinity for PPAR␥ is in the nanomolar range. The specificity of synthetic PPAR␥ agonists for PPAR␥ at the concentrations necessary for anti-inflammatory effects is thus in question. We report that PPAR␥ is not necessary for the inhibition of iNOS by synthetic PPAR␥ agonists. RAW 264.7 macrophages possess little PPAR␥, yet lipopolysaccharide (LPS)/interferon (IFN)␥-induced iNOS was inhibited by synthetic PPAR␥ agonists at 20 M. Endogenous PPAR␥ was inhibited by the transfection of a dominant-negative PPAR␥ construct into murine mesangial cells. In the transfected cells, synthetic PPAR␥ agonists inhibited iNOS production at 10 M, similar to nontransfected cells. Using cells from PPAR␥ Cre/lox conditional knockout mice, baseline and LPS/ IFN␥-induced nitric oxide levels were higher in macrophages lacking PPAR␥ versus controls. However, synthetic PPAR␥ agonists inhibited iNOS at 10 M in the PPAR␥-deficient cells, similar to macrophages from wild-type mice. These results indicate that PPAR␥ is not necessary for inhibition of iNOS expression by synthetic PPAR␥ agonists at concentrations over 10 M. Intrinsic PPAR␥ function, in the absence of synthetic agonists, however, may play a role in inflammatory modulation.Synthetic agonists of peroxisome proliferation-activated receptor (PPAR)␥, known as thiazolidinediones (TZDs), are currently being used for treatment of type II diabetes. Their clinical efficacy in diabetes coupled with the early reports of their effect on inflammatory mediator reduction in macrophage cell lines has lead to the study of PPAR␥ as an endogenous modulator of inflammation. The intrinsic ligand for PPAR␥ remains unclear. A prostaglandin J 2 metabolite was proposed to be an endogenous PPAR␥ agonist. This metabolite was shown effective at reducing markers of inflammation, such as inducible nitric-oxide synthase (iNOS), at concentrations less than 10 M (Jiang et al., 1998;Ricote et al., 1998;Petrova et al., 1999). However, it was later shown that in addition to binding to PPAR␥, 15-deoxy-⌬ 12,14 -prostaglandin J 2 (15dPGJ 2 ) also stabilized NF-B and prevented its activation of the iNOS promoter (Straus et al., 2000). A reactive metabolite, 15dPGJ 2 is capable of donating an electron to the NF-B. Recently, the lack of physiologic relevance of 15dPGJ 2 as an endogenous PPAR␥ agonist was demonstrated, and toxicity of the compound limits its clinical utility (Bell-Parikh et al., 2003). Thus, it is clear from a number of studies that PPAR␥ is not necessary for the anti-inflammatory properties of 15dPGJ 2 . This same PPAR␥-independent reactivity has not been reported for the synthetic PPAR␥ agonists s...

Fli1 is a member of the Ets family of transcription factors and is preferentially expressed in hematopoietic cell lineages. Its expression level is linked to the pathogenesis of lupus. In this study, we identified mechanisms involved in the transcriptional regulation of the mouse and human Fli1 promoters. We show that the Fli1 promoter is upregulated by Ets factors Ets1, Ets2, Fli1 and Elf1 either alone or in combination with GATA factors, but is inhibited by Tel. In vitro binding studies show that Elf1, Tel and Fli1 in T cells bind the three Ets-binding sites in the murine Fli1 proximal promoter. We identified transcription factorbinding sites in the human Fli1 promoter region that function in T cells in a similar manner to those in the mouse promoter. Furthermore, we show similar binding of Ets factors to the endogenous mouse and human Fli1 promoters in T cells and knocking down Ets1 results in an upregulation of Fli1 expression. Together, these results suggest that the human and mouse genes are regulated similarly and that Ets1 may be important in preventing the overexpression of Fli1 in T cells. This report lays the groundwork for identifying targets for manipulating Fli1 expression as a possible therapeutic approach.