MRL/lpr Mice (mrl/lpr + mouse)

Distribution by Scientific Domains

Selected Abstracts

Defective DNA methylation and CD70 overexpression in CD4+ T cells in MRL/lpr lupus-prone mice


Abstract We have determined that abnormal DNA methylation in T cells coincides with the development of autoimmunity, using a mouse model that exhibits an age-dependent lupus-like disease (MRL/lpr mice). Splenic CD4+ T cells were isolated from these mice at 5 and 16,wk of age (before and after autoimmunity is established) and the expression of DNA methyltransferase,1 (Dnmt1) and the methylation-sensitive gene Tnfsf7 (CD70) was measured. Bisulfite DNA sequencing was used to monitor the methylation status of the Tnfsf7 gene. We found that Dnmt1 steady-state mRNA levels were significantly lower in 16-wk-old MRL/lpr mice, which had established autoimmunity, compared to the 5-wk-old MRL/lpr mice. Furthermore, the expression of CD70 was higher in MRL/lpr mice at 16,wk. CD70 was overexpressed in MRL/lpr mice compared to age- and sex-matched MRL+/+ controls. Bisulfite DNA sequencing of the Tnfsf7 gene in MRL/lpr mice revealed that at 16,wk, CG pairs were hypomethylated compared to 5-wk-old mice, and that Tnfsf7 from MRL/lpr mice was hypomethylated at 16,wk relative to age-matched MRL+/+ controls. Our data indicate that decreased expression of Dnmt1 and the corresponding T cell DNA hypomethylation correlate with the development of age-dependent autoimmunity in MRL/lpr mice. [source]

Implication of allelic polymorphism of osteopontin in the development of lupus nephritis in MRL/lpr mice

Tatsuhiko Miyazaki
Abstract Potentially, autoimmune diseases develop from a combination of multiple genes with allelic polymorphisms. An MRL/Mp-Faslpr/lpr (MRL/lpr) strain of mice develops autoimmune diseases, including lupus nephritis, but another lpr strain, C3H/HeJ-Faslpr/lpr (C3H/lpr) does not. This indicates that MRL polymorphic genes are involved in the development of the diseases. By quantitative trait loci (QTL) analysis using 527 of the (MRL/lpr × C3H/lpr)F2 mice, we identified a novel locus for susceptibility to lupus nephritis at map position D5Mit115 on chromosome 5, the same alias of the osteopontin (Opn) gene (LOD score =4.0), susceptible in the MRL allele. In functional analyses of the MRL and C3H Opn alleles using synthetic osteopontin (OPN) made with a new method "cell-free system" with wheat germ ribosomes, the MRL-OPN induced higher expression and production of immunoglobulins as well as cytokines including TNF-,, IL-1, and IFN-, in splenocytes and/or macrophages than that of the C3H allele. These findings suggest that allelic polymorphism of OPN causes the functional differences in antibody production and macrophage activation between MRL and C3H strains, possibly involved in the development of lupus nephritis. [source]

Role of 2B4-mediated signals in the pathogenesis of a murine hepatitis model independent of Fas and V,14 NKT cells

IMMUNOLOGY, Issue 1pt2 2009
Hiroshi Furukawa
Summary Concanavalin A (Con A)-induced hepatitis is a T-cell-mediated murine experimental model of autoimmune hepatitis. Mice lacking V,14 NKT cells were found to be less sensitive to this hepatitis and the MRL/Mp- Faslpr/lpr (MRL/lpr; i.e. Fas deficient) mice were also less sensitive. We report herein that MRL/Mp- Faslpr/lpr - Saprpl/, (MRL/lpr/rpl) mice lack V,14 NKT cells and are deficient in the Fas antigen but sensitive to Con A-induced hepatitis. The signaling lymphocytic activation molecule (SLAM)-associated protein (SAP) is an adaptor molecule containing a Src homology 2 (SH2) domain. We previously reported new mutant mice found among MRL/lpr mice and revealed that SAP deficiency led to the regression of autoimmune phenotypes in mutant MRL/lpr/rpl mice. It was also revealed that CD4+ and CD8+ T cells were effector cells and that blockade of 2B4, one of the SLAM family receptors, inhibited the induction of hepatitis in MRL/lpr/rpl mice. These data suggest that signals mediated by molecules other than SAP from 2B4 in T cells played important roles in the induction of hepatitis in MRL/lpr/rpl mice. [source]

Novel recombinant congenic mouse strain developing arthritis with enthesopathy

Shiro Mori
Based on the hypothesis that the complex pathological and immunological manifestations of rheumatoid arthritis (RA) and the related diseases are under the control of multiple gene loci with allelic polymorphism, a recombinant congenic mouse strain was prepared between an MRL/Mp- lpr/lpr (MRL/lpr) strain, which develops arthritis resembling RA, and a non-arthritic strain C3H/HeJ- lpr/lpr (C3H/lpr). In MRL/lpr × (MRL/lpr × C3H/lpr) F1 mice, the mice developing severe arthritis were selected based on joint swelling to further continue intercrosses, and then an McH- lpr/lpr -RA1 (McH/lpr-RA1) strain was established and its histopathological phenotypes of joints and autoimmune traits were analyzed. Arthritis in McH/lpr-RA1 mice developed at a higher incidence by 20 weeks of age, compared with that in the MRL/lpr mice, who had severe synovitis (ankle, 60.3%; knee, 65.1%), and also fibrous and fibrocartilaginous lesions of articular ligamenta resembling enthesopathy (ankle, 79.4%; knee, 38.1%), resulting in ankylosis. The lymphoproliferative disorder was less, and serum levels of IgG and IgG autoantibodies including anti-dsDNA and rheumatoid factor were lower than those of both MRL/lpr and C3H/lpr strains. McH/lpr-RA1 mice may provide a new insight into the study of RA regarding the common genomic spectrum of seronegative RA and enthesopathy. [source]

Spontaneous occurrence of chronic non-suppurative destructive cholangitis and antimitochondrial autoantibodies in MRL/lpr mice: Possible animal model for primary biliary cirrhosis

Koichi Tsuneyama
MRL/MP mice bearing the lymphoproliferative gene lpr (known as MRL/MP- lpr/lpr or MRL/Ipr mice) are known to spontaneously develop severe autoimmune diseases such as glomerulonephritis, arteritis and arthritis at an early stage of their life. They have also been reported to develop severe sialadenitis, suggesting that this mouse could be a model for Sjögren's syndrome. Primary biliary cirrhosis, an autoimmune disease characterized by chronic non-suppurative destructive cholangitis and the occurrence of antimitochondrial antibodies, is frequently associated with Sjögren's syndrome. In this study, we examined whether cholangitis and/or antimitochondrial antibodies occur in this mouse model, using more than 100 young and old MRL/Ipr mice. We frequently found portal inflammation associated with cholangitis of small intrahepatic bile ducts, especially in older mice. There was also infiltration of inflammatory cells (monocytes) as well as CD4-positive T cells. Epithelioid granuloma and bile-duct loss were also occasionally found. These histological features resemble primary biliary cirrhosis. In addition, antimitochondrial antibodies were shown by immunocytochemistry to be present in the sera of MRL/Ipr mice. There is currently no established animal model for primary biliary cirrhosis. Therefore, further studies on MRL/Ipr mice, with respect to pathogenesis of primary biliary cirrhosis, are warranted. [source]

Targeted tumor necrosis factor receptor I preligand assembly domain improves skin lesions in MRL/lpr mice

Guo-Min Deng
Objective Skin disease is the second most common manifestation in patients with systemic lupus erythematosus (SLE). Tumor necrosis factor receptor (TNFR) preligand assembly domain (PLAD) has been found to block the effect of TNF,, and TNFRI PLAD (p60 PLAD) inhibits inflammatory arthritis. This study was undertaken to investigate whether TNFR PLAD limits inflammatory skin injury in a mouse model of SLE. Methods Female MRL/lpr mice received p60 PLAD (100 ,g/mouse intraperitoneally), p80 PLAD (100 ,g/mouse intraperitoneally), or phosphate buffered saline (100 ,l/mouse intraperitoneally) 3 times a week for 26 weeks, starting at age 6 weeks. Results Immunohistochemistry studies demonstrated that TNFRI but not TNFRII was dominantly expressed in skin lesions in MRL/lpr mice. We found that TNFRI PLAD (p60 PLAD) but not TNFRII PLAD (p80 PLAD) protein significantly inhibited skin injury in the MRL/lpr mouse model of lupus. NF-,B, monocyte chemotactic protein 1, and inducible nitric oxide synthase expression in skin lesions were significantly inhibited by p60 PLAD. Lupus serum,induced monocyte differentiation into dendritic cells was reduced by p60 PLAD, but p60 PLAD did not reduce IgG deposition in the skin or improve the progression of kidney damage in MRL/lpr mice. Conclusion Our results indicate that TNFRI is involved in the expression of skin injury in MRL/lpr mice with lupus and that p60 PLAD or similar biologics may be of clinical value if applied locally. [source]

Time course and nature of brain atrophy in the MRL mouse model of central nervous system lupus

John G. Sled
Objective Similar to patients with systemic lupus erythematosus, autoimmune MRL/lpr mice spontaneously develop behavioral deficits and pathologic changes in the brain. Given that the disease-associated brain atrophy in this model is not well understood, the present study was undertaken to determine the time course of morphometric changes in major brain structures of autoimmune MRL/lpr mice. Methods Computerized planimetry and high-resolution magnetic resonance imaging (MRI) were used to compare the areas and volumes of brain structures in cohorts of mice that differ in severity of lupus-like disease. Results A thinner cerebral cortex and smaller cerebellum were observed in the MRL/lpr substrain, even before severe autoimmunity developed. With progression of the disease, the brain area of coronal sections became smaller and the growth of the hippocampus was retarded, which likely contributed to the increase in the ventricle area:brain area ratio. MRI revealed reduced volume across different brain regions, with the structures in the vicinity of the ventricular system particularly affected. The superior colliculus, periaqueductal gray matter, pons, and midbrain were among the regions most affected, whereas the volumes of the parietal-temporal lobe, parts of the cerebellum, and lateral ventricles in autoimmune MRL/lpr mice were comparable with values in congenic controls. Conclusion These results suggest that morphologic alterations in the brains of MRL/lpr mice are a consequence of several factors, including spontaneous development of lupus-like disease. A periventricular pattern of parenchymal damage is consistent with the cerebrospinal fluid neurotoxicity, limbic system pathologic features, and deficits in emotional reactivity previously documented in this model. [source]

Th17 and natural Treg cell population dynamics in systemic lupus erythematosus

Ji Yang
Objective To investigate the relative abundance and activities of Th17 cells and natural Treg cells in systemic lupus erythematosus (SLE). Methods Blood samples were collected from 50 adult patients with SLE. Samples were processed to detect Th17 cells and natural Treg cells by flow cytometry, and related gene expression was assessed by real-time reverse transcription,polymerase chain reaction. Skin biopsy specimens were collected for histologic assessment. The function of Th17 cells in relation to human umbilical vein endothelial cells (HUVECs) was studied in vitro. Th17 cells were also examined in lupus-prone MRL/Mp- lpr/lpr (MRL/lpr) mice. Results We demonstrated the presence of Th17 cells among the peripheral blood mononuclear cells (PBMCs) and in the involved organs of patients with active SLE. Both the percentage of circulating Th17 cells and the ability to produce interleukin-17A (IL-17A) were increased in samples derived from patients with active SLE. The number of Th17 cells increased during SLE flare, especially in patients with vasculitis, and decreased following certain treatments. We observed that IL-17A from patients with SLE could induce adhesion molecule messenger RNA expression in HUVECs and adhesion of T cells to HUVECs. An increase in the percentage of Th17 cells was correlated with natural Treg cell depletion during disease flare. Finally, expansion of the Th17 cell population was detected in MRL/lpr mice. Conclusion SLE flare might be linked to the expansion of the Th17 cell population and the depletion of natural Treg cell subpopulations. Expansion of the Th17 cell population might be related to a distinct cytokine environment in active SLE. Th17 cells and microenvironmental IL-17A are involved in vascular inflammation in SLE. Antagonism of Th17 cells by IL-17A,blocking antibodies should be explored as a treatment of SLE. [source]

IK cytokine ameliorates the progression of lupus nephritis in MRL/lpr mice

Masatake Muraoka
Objective IK cytokine has been isolated as a factor that inhibits interferon-, (IFN,),induced expression of class II major histocompatibility complex (MHC) antigens. Aberrant expression of class II MHC antigens has reportedly been recognized in the target organs of autoimmune diseases and been associated with disease activity. In this study, we investigated whether IK cytokine can ameliorate the progression of lupus nephritis in MRL/lpr mice. Methods A truncated IK analog was prepared and transfected into a nonmetastatic fibroblastoid cell line, and then injected subcutaneously into MRL/lpr mice at ages 8 weeks (before the onset of lupus nephritis) and 12 weeks (at the early stage of the disease). Results An IK cytokine, when it was translated from methionine at position 316, acted as a secretory protein. This truncated IK cytokine (tIK) reduced IFN,-induced class II MHC expression in various cells through decreased expression of class II MHC transcription activator. Treatment of MRL/lpr mice with tIK significantly reduced renal damage as compared with control mice. A significant decrease in macrophage and T cell infiltration was found in the kidneys of tIK-treated mice, resulting in decreased production of IFN, and interleukin-2. Mice treated with tIK also showed significant reduction of anti-DNA antibodies and circulating immune complexes. A specific reduction of class II MHC expression was observed on B cells and monocytes as well as in the kidney. Conclusion We prepared a potent IK analog and demonstrated its ability to ameliorate the progression of lupus nephritis. This agent may therefore provide a new therapeutic approach for lupus nephritis. [source]

Nephritogenic Anti-DNA antibodies regulate gene expression in MRL/lpr mouse glomerular mesangial cells

Xiaoping Qing
Objective Lupus-associated IgG anti,double-stranded DNA antibodies are thought to be pathogenic in the kidney due to cross-reaction with glomerular antigens, leading subsequently to immune complex formation in situ and complement activation. We undertook this study to determine if pathogenic anti-DNA antibodies may also contribute to renal damage by directly influencing mesangial gene expression. Methods Complementary DNA microarray gene profiling was performed in primary mesangial cells (derived from lupus-prone MRL/lpr mice) treated with pathogenic, noncomplexed anti-DNA antibodies. Significant gene up-regulation induced by anti-DNA antibodies as determined by microarray analysis was further investigated by real-time polymerase chain reaction and methods to detect the relevant proteins. Induction of proinflammatory genes by pathogenic antibodies was confirmed by comparing gene expression in glomeruli of old versus young MRL/lpr mice, and by antibody injection in vivo. Results Pathogenic, but not nonpathogenic, antibodies significantly induced a number of transcripts, including CXCL1/KC, LCN2, iNOS, CX3CL1/fractalkine, SERPINA3G, and I,B, ("marker genes"). Blocking of Fc, receptors or using Fc, chain,knockout mesangial cells had no effect on the gene regulation effect of the pathogenic antibody R4A, indicating a non,Fc-dependent mechanism. The glomerular expression of these marker genes increased over time with the development of glomerular antibody deposition and active nephritis in MRL/lpr mice. Moreover, injection of R4A into SCID mice in vivo significantly up-regulated glomerular marker gene expression. Conclusion These findings indicate that the renal pathogenicity of anti-DNA antibodies may be attributed in part to their ability to directly modulate gene expression in kidney mesangial cells through both Fc-dependent and non,Fc-dependent mechanisms. [source]

Antagonist of monocyte chemoattractant protein 1 ameliorates the initiation and progression of lupus nephritis and renal vasculitis in MRL/lpr mice

Hitoshi Hasegawa
Objective To examine whether chemokine antagonists inhibit the initiation and progression of lupus nephritis in MRL/lpr mice. Methods NH2 -terminal,truncated monocyte chemoattractant protein 1 (MCP-1)/CCL2 or thymus and activation,regulated chemokine (TARC)/CCL17 analogs were inserted into the pCXN2 expression vector and transfected into a nonmetastatic fibroblastoid cell line, MRL/N-1, established from an MRL/gld mouse. Results MCP-1 antagonist, or TARC antagonist,transfected MRL/N-1 cells were injected subcutaneously into MRL/lpr mice ages 7 weeks (before the onset of lupus nephritis) and 12 weeks (at the early stage of the disease). After 8 weeks, mice bearing the MCP-1 antagonist showed markedly diminished infiltration of macrophages and T cells, glomerular hypercellularity, glomerulosclerosis, crescent formation, and vasculitis compared with control mice. This seemed to be due to decreased production of interferon-, and interleukin-2 in the kidney. In contrast, there was no significant difference in renal damage between mice bearing TARC antagonist and control mice. Conclusion We established a new system using MRL/N-1 cells that allows long-term observation of the effects of chemokine antagonists on lupus nephritis in MRL/lpr mice. We also showed that the MCP-1 antagonist ameliorated the initiation and progression of lupus nephritis and of renal vasculitis, which might provide a new approach to the treatment of the disease. [source]

Role of cytokines of the tumour necrosis factor family in the immune response to disseminated Candida albicans infection

M. G. Netea
Background Tumour necrosis factor (TNF) ,, lymphotoxin (LT) ,, CD40L and FasL are members of the TNF family that play a crucial role in modulation of the immune response. Their role in the defence against infection with Candida albicans was investigated in mice deficient in either TNF-, and LT-, (TNF,/, LT,/, mice), CD40L (CD40L,/, mice) or Fas (MRL/lpr mice). Methods Mortality rates were compared in mice infected intravenously with 106 colony-forming units of C. albicans per mouse. Results After infection with C. albicans the TNF,/, LT,/, mice had a significantly increased mortality rate compared with control mice (100 versus 40 per cent; P < 0·01). This was due to a 10,1000-fold increased outgrowth of the yeasts in the kidneys and liver of TNF,/, LT,/, mice (P < 0·01). Defective recruitment and phagocytosis, but not Candida killing, were responsible for these effects. CD40L,/, mice were also more susceptible to systemic candidiasis than the wild-type controls (mortality rate 80 versus 50 per cent; P < 0·05), and the growth of Candida in the kidneys was one order of magnitude higher in the deficient than in control mice (P < 0·05). Neutrophil function in the CD40L,/, mice was normal, whereas decreased Candida killing by macrophages through nitric oxide-dependent mechanisms was responsible for the effect of CD40/CD40L interactions. In contrast, Fas-defective MRL/lpr mice were significantly more resistant to disseminated candidiasis (mortality rate 50 versus 100 per cent; P < 0·01); this was mediated by the facilitation of neutrophil migration to the site of infection. Conclusion Cytokines of the TNF family play a crucial role in the modulation of host defence against fatal C. albicans infection. Their effects are exerted selectively at the level of neutrophil or macrophage function. © 2000 British Journal of Surgery Society Ltd [source]

Chemical induction of HO-1 suppresses lupus nephritis by reducing local iNOS expression and synthesis of anti-dsDNA antibody

SUMMARY There is accumulating evidence that haem oxygenase (HO)-1 plays a protective role in various disorders. The beneficial efficacy of HO-1 induction therapy has been shown in renal diseases such as glomerulonephritis, interstitial nephritis and drug induced nephrotoxicity. However, involvement of HO-1 in the development of autoimmune renal diseases remains uncertain. To assess the clinical efficacy of HO-1 induction therapy for lupus glomerulonephritis, MRL/lpr mice were intraperitoneally injected with 100 µmol/kg hemin, a potent HO-1 inducer, or PBS as controls, once a week from 6 weeks of age to 21,24 weeks-old. We found that treatment with hemin led to a significant reduction of proteinuria and remarkable amelioration of glomerular lesions accompanied by decreased immune depositions. In addition, the circulating IgG anti-double-stranded DNA antibody level was significantly decreased in hemin treated mice when compared with controls. A single intraperitoneal injection with hemin resulted in reduction of inducible nitric oxide synthase expression in the kidney and spleen, and serum interferon- , level. Our results suggest that HO-1 induction therapy ameliorates lupus nephritis by suppressing nitric oxide (NO) dependent inflammatory responses and attenuating production of pathogenic autoantibodies. [source]