Bortezomib treatment induces a higher mortality rate in lupus model mice with a higher disease activity.

BACKGROUND: Bortezomib (Bz) is a proteasome inhibitor that directly targets antibody-producing plasma cells. We recently reported the first randomized control trial that evaluated the effects of Bz in patients with systemic lupus erythematosus (SLE). In that study, we demonstrated that Bz treatment is associated with many adverse reactions in patients with refractory disease. In the present study, we examine the therapeutic and toxic effects of Bz on MRL/MpJ-lpr/lpr (MRL/lpr) mice with severe disease activity. METHODS: Female MRL/lpr mice at 10 and 14 weeks of age were treated with phosphate buffered saline (PBS) (n = 19), Bz (750 µg/kg twice weekly) (n = 27), or cyclophosphamide (Cyc) (1 mg/body, once in 2 weeks) (n = 20). Cellular subsets, serum immunoglobulin, anti-double-stranded DNA (anti-dsDNA) antibody titer, and a pathological index of glomerulonephritis were then analyzed at 22 weeks of age. Survival curves of the 10-week-old and 14-week-old Bz-treated groups were compared. Blood counts, creatinine, liver enzymes, and serum cytokine levels were measured 1 week after Bz treatment. Gene expression profiling of spleens from Bz and Cyc treatment mice were compared with those from control mice. RESULTS: The anti-dsDNA antibody levels were significantly higher in 14-week-old than in 10-week-old mice, indicating a higher disease activity at 14 weeks. A significant decrease in the number of splenic cells and glomerulonephritis index was observed in Bz-treated and Cyc-treated mice. Bz, but not Cyc, significantly decreased serum immunoglobulin and anti-dsDNA antibody titer levels. Survival curve analysis revealed a significantly higher mortality rate in 14-week-old than in 10-week-old Bz-treated and control groups. Following two injections of Bz, serum IL-6 and TNF-α levels were significantly more elevated in 14-week-old than in 10-week-old mice. Potentially immunogenic molecules, such as heat shock proteins, were characteristically upregulated in spleens of Bz-treated but not Cyc-treated mice. CONCLUSIONS: In spite of its therapeutic effect, Bz treatment had more toxic effects associated with increased proinflammatory cytokine levels in mice with a higher disease activity. Understanding the mechanism of the toxicity and developing preventive strategies against it is important for the safe clinical application of Bz in human SLE.

Strain differences in the proteome of dioxin-sensitive and dioxin-resistant mice treated with 2,3,7,8-tetrabromodibenzo-p-dioxin.

Dioxins cause various toxic effects through the aryl hydrocarbon receptor (AHR) in vertebrates, with dramatic species and strain differences in susceptibility. Although inbred mouse strains C3H/HeJ-lpr/lpr (C3H/lpr) and MRL/MpJ-lpr/lpr (MRL/lpr) are known as dioxin-sensitive and dioxin-resistant mice, respectively, the molecular mechanism underlying this difference remains unclear. The difference in the hepatic proteome of the two mouse strains treated with vehicle or 2,3,7,8-tetrabromodibenzo-p-dioxin (TBDD) was investigated by a proteomic approach of two-dimensional electrophoresis (2-DE) coupled with matrix-assisted laser desorption/ionization time-of-flight/time-of-flight tandem mass spectrometry (MALDI-TOF/TOF). To confirm the strain-difference in response to TBDD treatment, cytochrome P450 (CYP) 1A1 and 1A2 protein levels were measured in both strains. A dose of 10 µg/kg body weight of TBDD induced hepatic CYP1A1 and CYP1A2 expression in both strains, but the expression levels of both CYP1A proteins were higher in C3H/lpr mice than in MRL/lpr mice, supporting that C3H/lpr mice are more sensitive to dioxins than MRL/lpr mice. Proteins that were more induced or suppressed by TBDD treatment in C3H/lpr mice were successfully identified by 2-DE and MALDI-TOF/TOF, including proteins responsible for AHR activation through production of endogenous ligands such as aspartate aminotransferase, indolethylamine N-methyltransferase, and aldehyde dehydrogenases, as well as proteins reducing oxidative stress, such as superoxide dismutase and peroxiredoxins. Taken together, our results provide insights into the molecular mechanism underlying the high dioxin susceptibility of the C3H/lpr strain, in which AHR activation by TBDD is more prompted by the production of endogenous ligands, but the adaptation to oxidative stress is also acquired.

Autoantibody Profiles in Collagen Disease Patients with Interstitial Lung Disease (ILD): Antibodies to Major Histocompatibility Complex Class I-Related Chain A (MICA) as Markers of ILD.

Interstitial lung disease (ILD) is frequently associated with collagen disease. It is then designated as collagen vascular disease-associated ILD (CVD-ILD), and influences patients' prognosis. The prognosis of acute-onset diffuse ILD (AoDILD) occurring in patients with collagen disease is quite poor. Here, we report our investigation of auto-antibody (Ab) profiles to determine whether they may be useful in diagnosing CVD-ILD or AoDILD in collagen disease. Auto-Ab profiles were analyzed using the Lambda Array Beads Multi-Analyte System, granulocyte immunofluorescence test, Proto-Array Human Protein Microarray, AlphaScreen assay, and glutathione S-transferase capture enzyme-linked immunosorbent assay in 34 patients with rheumatoid arthritis (RA) with or without CVD-ILD and in 15 patients with collagen disease with AoDILD. The average anti-major histocompatibility complex class I-related chain A (MICA) Ab levels were higher in RA patients with CVD-ILD than in those without (P = 0.0013). The ratio of the average anti-MICA Ab level to the average anti-human leukocyte antigen class I Ab level (ie, MICA/Class I) was significantly higher in RA patients with CVD-ILD compared with those without (P = 4.47 × 10(-5)). To the best of our knowledge, this is the first report of auto-Ab profiles in CVD-ILD. The MICA/Class I ratio could be a better marker for diagnosing CVD-ILD than KL-6 (Krebs von den lungen-6).

A case of catastrophic antiphospholipid syndrome, which presented an acute interstitial pneumonia-like image on chest CT scan.

We report the case of catastrophic antiphospholipid syndrome (CAPS) complicated with mixed connective tissue disease (MCTD). A female patient was diagnosed with acute interstitial pneumonia (AIP) with MCTD by chest CT scan. Corticosteroid therapy was refractory for lung involvement, and she died due to acute respiratory failure. The autopsy revealed that AIP was compatible with lung involvement of CAPS. We therefore suggest that chest CT might reveal AIP-like findings in CAPS patients whose condition is complicated with pulmonary manifestations.

Novel role of hnRNP-A2/B1 in modulating aryl hydrocarbon receptor ligand sensitivity.

The aryl hydrocarbon receptor (AHR) is responsible for susceptibility to its ligand-dependent responses. However, the effect of non-AHR factors is less clear. To explore the non-AHR factors, we used two mouse strains with different AHR genetic variants, namely C3H/lpr and MRL/lpr strains with Ala and Val as the 375th amino acid residue, respectively. To assess the contribution of AHR alone, COS-7 cells transiently expressing AHR from each strain were treated with 6-formylindolo[3,2-b]carbazole (FICZ) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and xenobiotic-responsive element (XRE)-driven reporter gene activities were measured. FICZ-EC50 values for the C3H/lpr and MRL/lpr AHR-mediated transactivation were 0.023 and 0.046 nM, respectively, indicating a similar susceptibility in both AHR genotypes. In contrast, C3H/lpr AHR was fourfold more sensitive to TCDD than MRL/lpr AHR. By a pull-down assay using a XRE-containing PCR product as bait and the hepatic nuclear extracts of both FICZ-treated mouse strains, we identified two interacting proteins as heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP-A2) and its splicing variant (hnRNP-A2b). Immunoprecipitation assays demonstrated the AHR interaction with hnRNP-A2/B1. When hnRNP-A2 was co-expressed with the MRL/lpr or C3H/lpr AHR in COS-7, FICZ treatment decreased EC50 to about threefold in both AHR genotypes, compared with EC50 in AHR alone. Similarly, hnRNP-A2b co-expression also lowered the FICZ-EC50 values. In TCDD-treated COS-7, responses depended on the AHR genotype; while no change in TCDD-EC50 was observed for C3H/lpr AHR when hnRNP-A2 was co-expressed, the value was reduced to nearly tenfold for MRL/lpr AHR. Co-transfection with hnRNP-A2b attenuated the AHR sensitivity to TCDD. In conclusion, the hnRNP-A2/B1 interacting with AHR may be a modulator of the AHR ligand sensitivity.

Microvasculature of carotid atheromatous plaques: hemorrhagic plaques have dense microvessels with fenestrations to the arterial lumen.

BACKGROUND: Microvessels in atheromatous plaques are well known to play a role in plaque vulnerability associated with intraplaque hemorrhage, but their architecture remains unclear. The morphometry of the microvasculature and hemorrhage of human carotid atheromatous plaques (CAPs) were evaluated, and 3-dimensional (3D) reconstruction of the microvessels was performed. METHODS: CAPs were obtained by endarterectomy in 42 patients. The specimens were analyzed using light microscopy. Plaque hemorrhage was defined as an area-containing red blood cells (>1 mm2). To determine the histopathologic features of plaque hemorrhage, the plaque area was divided into 4 regions: cap, shoulder, lipid/necrotic core, and media. Then, the density of microvessels and macrophages in each region was quantified. Two representative lesions with either hemorrhagic or nonhemorrhagic plaque were cut into 90 serial sections. The sections were double stained with anti-CD34 and anti-α smooth muscle actin antibodies, scanned using a digital microscope, and reconstructed using TRI-SRF2 software. RESULTS: The hemorrhagic plaques showed a higher density of microvessels than nonhemorrhagic plaques in the shoulder, cap, and lipid/necrotic core (P=.03, .009, and .001, respectively), and there was positive correlations between its density and macrophages in each regions (P<.001, .001, and .019, respectively). 3D imaging also revealed dense microvessels with a network structure in the cap and shoulder regions of hemorrhagic plaques, and some of the vessels were fenestrated to the arterial lumen. CONCLUSIONS: The microvasculature of plaques with intraplaque hemorrhage was dense, some of which fenestrated to the arterial lumen. The pathologic 3D imaging revealed precise architecture of microvasculature of plaques.

Association between E-selectin expression and histopathological modification of glomerular lesions by non-nephritogenic IgM antibodies in experimental lupus nephritis.

OBJECTIVE: To examine the role played by E-selectin in bystander IgM-mediated modification of glomerular lesions in experimental lupus nephritis. METHODS: Experimental lupus SCID mice were induced by an intraperitoneal injection of clone 7B6.8, which was derived from a MRL/lpr mouse and shown to induce wire-loop type glomerular lesions. Mice were subsequently administered clone Sp6, a non-nephritogenic IgM antibody- producing hybridoma. E-selectin expression was then evaluated in glomeruli showing histopathological conversion of lesions from wire-loop-like to a cell-proliferative form. We also investigated the effects of a circulating soluble form of E-selectin (sE-selectin) on the modification of glomerular lesions in this lupus model. RESULTS: In experimental lupus mice, glomerular E-selectin expression significantly increased during the conversion from wire-loop-like glomerular lesions to a cell-proliferative type mediated by a non-nephritogenic bystander IgM antibody in presence of a nephritogenic antibody. Intraglomerular infiltration of CD68 + macrophages correlated significantly with the glomerular level of E-selectin expression. In addition, overexpression of circulating sE-selectin significantly suppressed conversion to cell-proliferative glomerular lesions and glomerular macrophage infiltration in these lupus model mice. CONCLUSIONS: The histopathological modification of lupus nephritis by non-nephritogenic bystander IgM antibodies is associated in part with glomerular E-selectin expression.

A novel autoantibody against ephrin type B receptor 2 in acute necrotizing encephalopathy.

Acute necrotizing encephalopathy (ANE) is characterized by symmetrical brain necrosis, suggested to be due to breakdown of the blood-brain barrier (BBB). We experienced a rare case of ANE complicated with systemic lupus erythematosus (SLE), and found that the patient's serum (V10-5) had binding activity to human umbilical vein endothelial cells (HUVECs). By SARF (Serological identification system for Autoantigens using a Retroviral vector and Flow cytometry) method using V10-5 IgG, a clone bound to V10-5 IgG was isolated. This cell clone was integrated with cDNA identical to EphB2, which plays critical roles in neuronal cells and endothelial cells. HUVECs and human brain microvascular endothelial cells expressed EphB2 and the V10-5 IgG bound specifically to EphB2-transfected cells. Anti-EphB2 antibody was not detected in other SLE patients without ANE. In this report, we identified EphB2 as a novel autoantigen, and anti-EphB2 antibody may define a novel group of brain disorders. Anti-EphB2 antibody can interfere not only with endothelial cells including those of the BBB (acting as an anti-endothelial cell antibody), but also neuronal cells (acting as an anti-neuronal antibody) if the BBB has been breached. Future studies should determine the clinical prevalence and specificity of anti-EphB2 antibody, and the molecular mechanisms by which anti-EphB2 antibody mediates neuronal and vascular pathological lesions.

Polyarteritis nodosa clinically mimicking nonocclusive mesenteric ischemia.

Here, we present the case of a 74-year-old Japanese man with segmental intestinal necrosis, which developed after treatment with pulsed methylprednisolone for mononeuritis multiplex. The patient was weakly positive for myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibody (ANCA). Computed tomography and surgical findings were compatible with nonocclusive mesenteric ischemia (NOMI). He underwent small intestinal resection by emergency surgery and an intestinal fistula was made. Pathologically, necrotizing vasculitis with fibrinoid necrosis was present in medium to small-sized arteries, which was equivalent to Arkin's classification II-IV. Most of the arteries had fibrous intimal thickening, which was considered to obstruct the arteries and thus cause segmental intestinal necrosis. A diagnosis of polyarteritis nodosa (PAN) was made, and intravenous cyclophosphamide pulse therapy was added to the therapeutic regimen. This patient was successfully treated with these multidisciplinary therapies and his stoma was finally closed. This is a very rare and indicative case of PAN weakly positive for MPO-ANCA and clinically mimicking NOMI, which occurred even after treatment with pulsed methylprednisolone.

Genomics of vasculitis: lessons from mouse models.

A genome analysis of mouse models may shed some light on the complex clinicopathological manifestations of systemic vasculitis. In the study of susceptibility loci to vasculitis in MRL mouse models, we found that systemic vasculitis developed through the cumulative effect of multiple gene loci, each of which by itself did not have a significant effect in inducing the related phenotype, thus indicating a polygenic system. The mice developed vasculitis in an additive manner with a hierarchical effect. Some of the susceptibility loci seemed to be common to those in other collagen diseases. Moreover, the loci controlling tissue specificity of vasculitis were present. One of the positional candidate genes for vasculitis showed an allelic polymorphism in the coding region, thus possibly causing a qualitative difference in its function. As a result, a particular combination of polygenes with such an allelic polymorphism may thus play a critical role in leading the cascade reaction to develop vasculitis, and also a regular variation of systemic vasculitis. This is designated as the polygene network in systemic vasculitis. (J Jpn Coll Angiol, 2009, 49: 11-16).

A bacterial artificial chromosome transgene with polymorphic Cd72 inhibits the development of glomerulonephritis and vasculitis in MRL-Faslpr lupus mice.

Systemic lupus erythematosus is considered to be under the control of polygenic inheritance, developing according to the cumulative effects of susceptibility genes with polymorphic alleles; however, the mechanisms underlying the roles of polygenes based on functional and pathological genomics remain uncharacterized. In this study, we substantiate that a CD72 polymorphism in the membrane-distal extracellular domain impacts on both the development of glomerulonephritis and vasculitis in a lupus model strain of mice, MRL/MpJ-Fas(lpr), and the reactivity of BCR signal stimulation. We generated mice carrying a bacterial artificial chromosome transgene originating from C57BL/6 (B6) mice that contains the Cd72(b) locus (Cd72(B6) transgenic [tg]) or the modified Cd72(b) locus with an MRL-derived Cd72(c) allele at the polymorphic region corresponding to the membrane-distal extracellular domain (Cd72(B6/MRL) tg). Cd72(B6) tg mice, but not Cd72(B6/MRL) tg mice, showed a significant reduction in mortality following a marked improvement of disease associated with decreased serum levels of IgG3 and anti-dsDNA Abs. The number of splenic CD4(-)CD8(-) T cells in Cd72(B6) tg mice was decreased significantly in association with a reduced response to B cell receptor signaling. These results indicate that the Cd72 polymorphism affects susceptibility to lupus phenotypes and that novel functional rescue by a bacterial artificial chromosome transgenesis is an efficient approach with wide applications for conducting a genomic analysis of polygene diseases.

Toxicokinetics of dioxins and other organochlorine compounds in Japanese people: association with hepatic CYP1A2 expression levels.

Concentrations of persistent organochlorine compounds (OCs) including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) in the liver and adipose tissue of Japanese cadavers were measured, and their toxicokinetics were examined in association with hepatic cytochrome P450 (CYP) 1A protein expression levels. Total 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) were 66±74 and 65±57 pg/g lipid weight (mean±S.D.) in the liver and adipose tissue, respectively. Total PCBs (sum of 62 congeners targeted), p,p'-dichlorodiphenyl-dichloroethylene (p,p'-DDE) and ß-hexachlorocyclohexane (ß-HCH) were detected at concentrations over 1 µg/g lipid in both tissues of some specimens. For most of the dioxin-like congeners, total PCBs, p,p'-DDE, oxychlordane, α- and ß-HCH, hexachlorobenzene (HCB), and tris(4-chlorophenyl)methane (TCPMe), age-dependent increases in concentrations were found in the adipose tissue of males. No such age-dependent trend was observed in the liver, suggesting that there are different mechanisms underlying the hepatic concentrations of OCs. Immunoblot analyses indicated detectable expression of hepatic CYP1A2 protein, whereas no CYP1A1 protein was detected. The CYP1A2 expression levels were positively correlated with concentrations (on wet weight basis) of 2,3,4,7,8-P5CDF, the dominant TEQ-contributed congeners in the liver, indicating the induction of this CYP. Hepatic CYP1A2 protein levels were strongly correlated with the liver to adipose concentration (L/A) ratios of PCDD/F congeners with more than 5 chlorine atoms. Together with higher concentrations of the congeners in the liver than in the adipose tissue, the observation on L/A ratios of highly chlorinated PCDD/Fs suggests that induced hepatic CYP1A2 protein is involved in their sequestration in this human population, as observed in model animals (rodents). Nonetheless, the magnitude of hepatic sequestration (L/A ratio) of PCDD/Fs in this human population was lower than in other mammals and birds, reported previously. This study emphasizes the fact that toxicokinetics of some OCs can be affected at least partly by CYP1A2 protein levels in humans. For the extrapolation of their toxicokinetics from model animals to humans, knowledge on the induction and sequestration potencies of CYP1A is necessary.

Enhanced expression of the soluble form of E-selectin attenuates progression of lupus nephritis and vasculitis in MRL/lpr mice.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that causes inflammatory tissue damage, including lupus nephritis and vasculitis. Local generation of adhesion molecules and expression of their ligands on inflammatory cells appears to contribute to the progression of SLE. We found significantly increased E-selectin expression in the glomeruli and renal interstitial microvasculature of MRL/MpJ-lpr/lpr (MRL/lpr) lupus model mice. This was accompanied with infiltration of inflammatory cells, especially macrophages and CD8(+) T cells. Similarly, in 21 patients with proliferative lupus nephritis, there was a significant correlation between renal E-selectin levels and macrophage and CD8(+) T cell infiltration in the affected kidneys. By contrast, in transgenic MRL/lpr mice exhibiting elevated levels of circulating soluble E-selectin (sE-selectin) protein, which competitively inhibits E- and P-selectin-mediated extravasation of inflammatory cells, the progression of lupus nephritis and vasculitis was significantly suppressed and survival was significantly prolonged. This improvement was accompanied by significant reductions in renal infiltration by macrophages and CD8(+) T cells. These results suggest that E-selectin plays a crucial role in lupus nephritis and vasculitis by mediating renal infiltration of inflammatory cells, and that because it inhibits this process, sE-selectin could potentially serve as an effective treatment for lupus nephritis and vasculitis.

BAZF, a novel component of cullin3-based E3 ligase complex, mediates VEGFR and Notch cross-signaling in angiogenesis.

Angiogenic homeostasis is maintained by a balance between vascular endothelial growth factor (VEGF) and Notch signaling in endothelial cells (ECs). We screened for molecules that might mediate the coupling of VEGF signal transduction with down-regulation of Notch signaling, and identified B-cell chronic lymphocytic leukemia/lymphoma6-associated zinc finger protein (BAZF). BAZF was induced by VEGF-A in ECs to bind to the Notch signaling factor C-promoter binding factor 1 (CBF1), and to promote the degradation of CBF1 through polyubiquitination in a CBF1-cullin3 (CUL3) E3 ligase complex. BAZF disruption in vivo decreased endothelial tip cell number and filopodia protrusion, and markedly abrogated vascular plexus formation in the mouse retina, overlapping the retinal phenotype seen in response to Notch activation. Further, impaired angiogenesis and capillary remodeling were observed in skin-wounded BAZF(-/-) mice. We therefore propose that BAZF supports angiogenic sprouting via BAZF-CUL3-based polyubiquitination-dependent degradation of CBF1 to down-regulate Notch signaling.

Plasma thrombin-cleaved osteopontin elevation after carotid artery stenting in symptomatic ischemic stroke patients.

Atherothrombosis is the primary pathophysiology that underlies ischemic cerebral infarction. Osteopontin (OPN) is produced in atherosclerotic lesions and is cleaved by activated thrombin. We hypothesized that the rupture or damage of an unstable atherosclerotic plaque increases plasma levels of thrombin-cleaved OPN (trOPN). This study included 90 patients who received carotid angioplasty with stenting (CAS), 23 patients with essential hypertension (EHT) and 10 patients who were treated with carotid endarterectomy (CEA). The CAS patient group included 36 patients that had pre- and post-operative blood tests, diffusion-weighted imaging (DWI) using cerebral MRIs and estimated thrombus debris within the protection device. Immunohistochemistry of CEA specimens revealed that trOPN was detected around intra-plaque vessels. The highest tertile of plasma trOPN levels in CAS patients was higher than trOPN levels in EHT patients. Post-operative trOPN levels were significantly higher in symptomatic compared with asymptomatic patients (P=0.003). New ipsilateral DWI-positive patients revealed higher post-operative trOPN levels (P=0.003) and a higher grade of thrombi (P<0.001) than DWI-negative patients. TrOPN may be a novel biomarker that reflects the atherothrombotic status in ischemic stroke.

Indispensable roles of OX40L-derived signal and epistatic genetic effect in immune-mediated pathogenesis of spontaneous pulmonary hypertension.

BACKGROUND: Pulmonary hypertension (PH) refers to a spectrum of diseases with elevated pulmonary artery pressure. Pulmonary arterial hypertension (PAH) is a disease category that clinically presents with severe PH and that is histopathologically characterized by the occlusion of pulmonary arterioles, medial muscular hypertrophy, and/or intimal fibrosis. PAH occurs with a secondary as well as a primary onset. Secondary PAH is known to be complicated with immunological disorders. The aim of the present study is to histopathologically and genetically characterize a new animal model of PAH and clarify the role of OX40 ligand in the pathogenesis of PAH. RESULTS: Spontaneous onset of PAH was stably identified in mice with immune abnormality because of overexpression of the tumor necrosis factor (TNF) family molecule OX40 ligand (OX40L). Histopathological and physical examinations revealed the onset of PAH-like disorders in the C57BL/6 (B6) strain of OX40L transgenic mice (B6.TgL). Comparative analysis performed using different strains of transgenic mice showed that this onset depends on the presence of OX40L in the B6 genetic background. Genetic analyses demonstrated a susceptibility locus of a B6 allele to this onset on chromosome 5. Immunological analyses revealed that the excessive OX40 signals in TgL mice attenuates expansion of regulatory T cells the B6 genetic background, suggesting an impact of the B6 genetic background on the differentiation of regulatory T cells. CONCLUSION: Present findings suggest a role for the OX40L-derived immune response and epistatic genetic effect in immune-mediated pathogenesis of PAH.

A polygene network model for the complex pathological phenotypes of collagen disease.

Almost 70 years after the description of 'collagen disease' by P. Klemperer et al., it is still controversial whether the diversity and similarity of pathological manifestations among the collagen diseases depends on ambiguity in diagnosis or is an intrinsic quality of the collagen diseases themselves. A genome wide analysis of the MRL mouse models of collagen disease may shed some light on the complex pathological manifestations. Study of the susceptibility loci to each type ofcollagen disease (such as glomerulonephritis, vasculitis, arthritis, sialoadenitis and dacryoadenitis) in the mice, revealed that these lesions developed because of a cumulative effect of multiple gene loci, none of which can induce the related phenotype alone. This may indicate that collagen disease develops in 'a polygenic system', as proposed by K. Mather in 1949. Each lesion in the mice developed because of an additive effect of the polygenes, which is also, in part, hierarchical. Some of the polygenes seemed to be common to those in other collagen diseases as well. Some of the positional candidate genes involved an allelic polymorphism in the coding or promoter regions, thus possibly causing a qualitative or quantitative difference in their function, respectively. As a result, a particular combination of the polygenes with such an allelic polymorphism may thus play a critical role in leading the cascade reaction to developing collagen disease, and also the regular variation in the pathological manifestations. We herein describe this as a polygene network of collagen disease.

Role of the MICA polymorphism in systemic lupus erythematosus.

OBJECTIVE: To study the genetic contribution of major histocompatibility complex class I polypeptide-related sequence A (MICA), important in natural killer (NK) cell function, in patients with systemic lupus erythematosus (SLE). METHODS: Japanese patients with SLE (n=716), those with rheumatoid arthritis (RA) (n=327), and healthy control subjects (n=351) were genotyped for the Val129 Met polymorphism (rs1051792) and transmembrane (TM) alanine-encoding GCT repeats, termed A4, A5, A5.1, A6, and A9, in the MICA gene. Recombinant human MICA-GST fusion proteins were tested on the NK cell line NK92MI for the expression of NK group 2, member D (NKG2-D), NK cell-mediated cytotoxicity, and interferon-γ (IFNγ) production. RESULTS: The MICA 129Met allele, TMA9 allele, and 129Met/Met genotype were positively associated with SLE (corrected P [Pcorr]=0.01 and odds ratio [OR] 1.3, Pcorr=0.003 and OR 1.6, and Pcorr=0.02 and OR 1.8, respectively), while the MICA 129Val allele was negatively associated with SLE (Pcorr=0.01, OR 0.8). The MICA 129Met;A9 haplotype was also associated with SLE (Pcorr=0.0006, OR 1.8), and there was an additive genetic effect between the MICA 129Met;A9 haplotype and HLA-DRB1*15:01. When NK92MI cells were incubated in vitro with recombinant human disease-associated 129Met;A9 (the combination of polymorphisms at 129Met and TMA9), expression of NKG2-D on NK92MI cells and cytotoxicity of the NK cells were inhibited, but production of IFNγ from NK92MI cells was enhanced. CONCLUSION: The MICA polymorphism is genetically associated with SLE, and MICA appears to contribute to the pathogenesis of SLE by modulating NK cell function.

Kyoto rhino rats derived by ENU mutagenesis undergo congenital hair loss and exhibit focal glomerulosclerosis.

N-ethyl-N-nitrosourea (ENU) mutagenesis is an important tool for studying gene function and establishing human disease models. Here, we report the characterization of a novel hairless mutant rat strain that carries a recessive mutation called Kyoto rhino (krh), which was created by ENU-mutagenesis. We produced a F344-krh strain through inbreeding without backcrossing to F344 rats. The krh/krh rats lost their coat hair by eight weeks of age. They also developed wrinkled skin, cystic hair canals and long curved nails by four months of age. Markedly dilated hair follicles that contained keratin debris were observed during histological analysis of the skin. The krh locus was mapped near the hairless (Hr) gene on chromosome 15. Sequence analysis revealed a nonsense mutation (c. 1238 C>A, p. S413X) in the Hr gene. The truncated HR protein was deduced to lack a zinc-finger domain and repression domains. In aged Hr(krh)/Hr(krh) rats, focal glomerulosclerosis (FGS) was observed in which collapsed glomeruli contained protein exudates in Bowman's capsule. Mesangial matrices that had proliferated in segments and foot processes that were fused in podocytes were also observed. The Hr(krh)/Hr(krh) rats also suffered from significant proteinuria. Given its breeding history, the F344-Hr(krh) strain may harbor ENU-induced mutation(s) that underlie FGS in addition to having the Hr(krh) mutation. The F344-Hr(krh) rat is a useful model of skin disease and may provide a new model system for the examination of the pathogenesis of FGS.

Synovial hemangioma of the knee joint in a 3-year-old girl.

Synovial hemangioma has been reported to be relatively rare, and usually occurs in childhood and adolescence. However, there are a few reports of the disease in infants. In this report, we diagnosed synovial hemangioma in a 3-year-old girl who had swelling and pain in her left knee. Gadolinium-enhanced magnetic resonance imaging revealed abnormal intensity in an intra-articular lesion. We performed arthroscopy, and arrived at a final diagnosis based on a scopic biopsy. Synovial hemangioma should be considered as a possible diagnosis in infants with swelling and pain in the knee.