Novel recombinant congenic mouse strain developing arthritis with enthesopathy

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 x (MRL/lpr x 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.

Augmentation of osteopontin expression in renal tubuli is independent of a histopathological type of glomerular lesions in mouse lupus nephritis

Augmentation of osteopontin (OPN) expression in renal tubuli is often observed in lupus nephritis. To investigate whether this might depend on histopathological type of glomerular lesions, comparative studies of the distribution and levels of OPN expression in kidneys were performed by in situ hybridization and real-time polymerase chain reaction in mouse lupus nephritis manifesting inflammatory (endocapillary proliferative) and deposit (wire loop) types of glomerular lesions. These glomerular lesions were developed in C.B-17/Inc-scid/scid mice by injection of IgG3 antibody producing hybridoma clones, 2B11.3 and 7B6.8, respectively, which are derived from an MRL/Mp-lpr/lpr (MRL/lpr) lupus mouse. Both clones significantly augmented OPN expression in renal tubuli, but a non-nephritogenic IgG3 clone, 1G3, derived from the same MRL/lpr mouse, did not. The OPN augmentation was prominent in the renal cortex and the inner stripe of the outer medulla. These results indicate that OPN augmentation in renal tubuli is not associated with a histopathological type of glomerular lesion in lupus nephritis, at least not with an inflammatory or a deposit type.

A signal adaptor SLAM-associated protein regulates spontaneous autoimmunity and Fas-dependent lymphoproliferation in MRL-Faslpr lupus mice

Autoantibody production and lymphadenopathy are common features of systemic autoimmune disease. Targeted or spontaneous mutations in the mouse germline have generated many autoimmune models with these features. Importantly, the models have provided evidence for the gene function in prevention of autoimmunity, suggesting an indispensable role for the gene in normal immune response and homeostasis. We describe here pathological and genetic characterizations of a new mutant strain of mice, the mutation of which spontaneously occurred in the Fas-deficient strain, MRL/Mp.Faslpr (MRL/lpr). MRL/lpr is known to stably exhibit systemic lupus erythematosus-like diseases. However, the mutant mice barely displayed autoimmune phenotypes, though the original defect in Fas expression was unchanged. Linkage analysis using (mutant MRL/lpr x C3H/lpr)F2 mice demonstrated a nucleotide insertion that caused loss of expression of small adaptor protein, signaling lymphocyte activation molecule (SLAM)-associated protein (SAP). SAP is known to be a downstream molecule of SLAM family receptors and to mediate the activation signal for tyrosine kinase Fyn. Recent studies have shown pleiotropic roles of SAP in T, B, and NK cell activations and NKT cell development. The present study will provide evidence for an essential role for SAP in the development of autoimmune diseases, autoantibodies, and lymphadenopathy in MRL/lpr lupus mice.

Secondary amyloidosis and eosinophilia in a patient with uterine leiomyosarcoma

We report a rare case demonstrating the relationship between secondary amyloidosis and uterine leiomyosarcoma. A 59-year-old female with high fever was referred to our hospital. Laboratory tests revealed increased white blood cells, eosinophilia and an accelerated erythrocyte sedimentation rate. Endoscopic examination of the stomach and colon revealed amyloid deposits in their mucosa. The patient showed no symptoms that suggested amyloidosis. No other organs or tissues were surveyed for amyloid deposition. Ga scintigraphy, computed tomography and magnetic resonance imaging suggested necrotic infectious leiomyoma of the uterus, which was considered to be the cause of the fever. The patient underwent total hysterectomy. The histological diagnosis of the mass revealed a low-grade uterine leiomyosarcoma with necrosis. Amyloid deposits in the gastric mucosa disappeared 1 year after the operation. In this case, amyloid deposition was detected by endoscopic biopsy before clinical manifestations. The deposition was reversible and was successfully treated. Thus, it is logical and useful to undertake endoscopic mucosa biopsy to check for amyloid deposition in patients with systemic inflammation, whose serum amyloid A protein level has been high for several months. In addition, peripheral eosinophilia was also detected in this case. Although eosinophilia associated with malignant tumor has been recognized, it is an uncommon occurrence.

Antagonist of fractalkine (CX3CL1) delays the initiation and ameliorates the progression of lupus nephritis in MRL/lpr mice

OBJECTIVE

Lupus nephritis is characterized by immune complex deposition and inflammatory cell infiltration into the renal glomeruli. Local generation of chemokines and the presence of chemokine receptors on the infiltrating cells may be involved in this process. Fractalkine (Fkn)/CX3CL1 and its receptor, CX3CR1, form one such chemokine system. We therefore undertook this study to investigate whether Fkn antagonist inhibits the initiation and progression of lupus nephritis in MRL/lpr mice.

METHODS

NH(2)-terminally truncated Fkn/CX3CL1 analogs were transfected into a nonmetastatic fibroblastoid cell line, MRL/N-1, and injected subcutaneously into MRL/lpr mice.

RESULTS

Fkn analogs truncated by >/=4 amino acid residues from the N-terminus failed to induce chemotaxis and calcium influx by CX3CR1-expressing cells. Of these, the most potent antagonist (Fkn-AT) lacked the 4 N-terminal amino acid residues. Fkn expression in the glomerulus was significantly increased in 12-week-old MRL/lpr mice. Expression was localized predominantly in the glomerular endothelial cells, but was occasionally observed in the mesangial cells and, to a lesser extent, in the interstitial microvasculature. Inoculation of MRL/lpr mice with Fkn-AT before the onset or during the early stages of lupus nephritis significantly reduced glomerular hypercellularity, glomerulosclerosis, crescent formation, and vasculitis compared with control mice. This seemed to be due to a marked reduction in macrophage accumulation. In contrast, Fkn antagonist did not affect pneumonitis, sialadenitis, lymphadenopathy, or splenomegaly.

CONCLUSION

We prepared a novel potent Fkn antagonist and demonstrated its ability to delay the initiation and ameliorate the progression of lupus nephritis. This agent may therefore provide a new therapeutic approach to lupus nephritis.

Rupture of the gallbladder in a patient with acquired factor VIII inhibitors and systemic lupus erythematosus

A 54-year-old woman with a 21-year history of systemic lupus erythematosus (SLE) was admitted to the Matsuyama Red Cross Hospital due to subcutaneous and gingival hemorrhaging. She was diagnosed with acquired factor VIII inhibitors based on a prolonged activated partial-thromboplastin time (APTT) and factor VIII inhibitors. Steroid pulse and factor VIII plasma concentrate were administered to her, not long after which she was transferred to Ehime University Hospital due to gallbladder hematoma. Although her APTT and factor VIII activity were improved after treatment with human factor VIII, she died of multiple organ failure. The autopsy demonstrated a ruptured gallbladder.

Endothelial adhesion molecules in glomerular lesions: association with their severity and diversity in lupus models

BACKGROUND

To clarify whether vascular endothelial adhesion molecules in glomeruli might contribute to the severity and diversity of glomerular lesions in lupus nephritis, their expression in lupus models was analyzed.

METHODS

The expression levels of E- and P-selectin and vascular cell adhesion molecule-1 (VCAM-1) in glomeruli of different histopathologic grades of MRL/MpJ-lpr/lpr (MRL/lpr) lupus mice was studied using laser-capture microdissection of the glomeruli, followed by reverse transcription-polymerase chain reaction (RT-PCR) analysis. The glomerular lesions in SCID mice injected with the 2B11.3 and 7B6.8 clones, which are derived from an MRL/lpr mouse and induce endocapillary proliferative and wire loop type of glomerular lesions, respectively, were analyzed. To investigate the effect of a soluble form of E-selectin (sE-selectin) on the development of glomerular lesions, sE-selectin-producing L cells were prepared by transfection of the cDNA encoding sE-selectin and injected into SCID mice.

RESULTS

The glomeruli in MRL/lpr mice showed increased expression of these adhesion molecules, corresponding to the severity of the glomerular lesions. The endocapillary proliferative type lesions in SCID mice induced by the 2B11.3 clone showed significantly increased expression of the adhesion molecules, especially E-selectin and P-selectin, but the wire loop type lesion induced by the 7B6.8 clone expressed only VCAM-1. Formation of the endocapillary proliferative type lesions induced by the 2B11.3 clone was markedly prevented in association with elevation of the serum level of sE-selectin produced by the tansfected L cells.

CONCLUSION

The severity and diversity of the histopathology of lupus nephritis are partially associated with the expression of vascular endothelial adhesion molecules in glomeruli.

Internalization of antibodies by endothelial cells via fibronectin implicating a novel mechanism in lupus nephritis

BACKGROUND

One of the crucial events in lupus nephritis is the glomerular deposition of immunoglobulins (Igs), of which pathogenic properties have been proposed mostly to be either type IIor type III allergic reactions. Some of IgG3-producing hybridoma clones established from an MRL/MpTn-gld/gld (MRL/gld) lupus mouse generate wire loop-like lesions in glomeruli resembling lupus nephritis when injected into SCID mice. These clones are useful for analyzing the mechanisms of glomerular deposition of antibodies in lupus nephritis at the monoclonal level.

METHODS

Glomerular lesions of SCID mice injected with the hybridoma clones, 17H8a or 1G3 as control were analyzed by light and electron microscopy. Interaction of the antibodies with human glomerular endothelial cells (HGECs) and human umbilical vein endothelial cells (HUVECs) in vitro was studied by fluorescence microscopy, electron microscopy, and flow cytometry.

RESULTS

Both antibodies did not show any antigen specificity for mouse glomeruli. The glomerular lesions generated by 17H8a, but not by 1G3, contained electron-dense deposits not only in subendothelial regions but also in the cytoplasm of endothelial cells, suggesting internalization of the 17H8a antibodies by endothelial cells. In cell culture studies, internalization of only 17H8a antibodies by HGECs and HUVECs was observed, but the antibodies did not have antigen specificity for both types of endothelial cells. The internalization by HUVECs was mediated by actin polymerization, and it was inhibited by RGDS (Arg-Gly-Asp-Ser) tetrapeptide, antihuman fibronectin and antihuman integrin beta1 monoclonal antibodies.

CONCLUSION

The interaction between particular antibodies and endothelial cell surface integrins via fibronectin may be involved in their subsequent internalization by endothelial cells leading to antibody deposition in glomeruli. This may be one of the mechanisms of glomerular injury in lupus nephritis.

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

OBJECTIVE

To examine whether chemokine antagonists inhibit the initiation and progression of lupus nephritis in MRL/lpr mice.

METHODS

NH(2)-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-gamma 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.

Bone marrow cell transfer of autoimmune diseases in a MRL strain of mice with a deficit in functional Fas ligand: dissociation of arteritis from glomerulonephritis

MRL/MpTn-gld/gld (MRL/gld) mice, which are deficient in a functional Fas ligand (FasL), spontaneously develop autoimmune diseases involving both lethal glomerulonephritis and systemic arteritis, while MRL/Mp-+/+ (MRL/+) and C3H/HeJ-gld/gld (C3H/gld) do not. To determine the cells responsible for the development of glomerulonephritis and arteritis, we transferred bone marrow cells from MRL/gld mice to undiseased MHC-compatible gld/gld or +/+ mice. In bone marrow irradiation chimeras, MRL/gld bone marrow cells were transferred to lethally irradiated MRL/+ or C3H/HeJ-+/+ (C3H/+) mice, and both recipients developed glomerulonephritis associated with hypergammaglobulinemia without causing graft-versus-host (GVH)-like diseases. However, a striking difference between them was that MRL/+ recipients developed arteritis, but C3H/+ recipients did not. In bone marrow mixed chimeras formed by transferring MRL/gld bone marrow cells to unirradiated mice, the MRL/gld bone marrow cells induced glomerulonephritis in C3H/gld mice, but not in C3H/+ and MRL/+ mice. These results indicate that bone marrow cells from MRL/gld mice can cause glomerulonephritis in mice, even in those with a C3H background, possibly if they survive longer by escaping from Fas-mediated apoptosis, while the development of arteritis requires the MRL genetic background in the recipients. This is the first report of the transfer of arteritis in lupus mice to undiseased recipients.

Genetic basis of tissue specificity of vasculitis in MRL/lpr mice

OBJECTIVE

To clarify the mode of inheritance of the tissue distribution of vasculitis in MRL/Mp-lpr/lpr (MRL/lpr) lupus-prone mice and to identify the susceptibility loci.

METHODS

Vasculitis in individual MRL/lpr, C3H/HeJ-lpr/lpr (C3H/lpr), (MRL/lpr x C3H/lpr)F(1), and (MRL/lpr x C3H/lpr)F(2) intercross mice was analyzed by histopathologic grading of main branches of the aorta and of medium-sized arteries in the lower limbs. Genomic DNA samples from F(2) intercross mice were examined by simple sequence-length polymorphism analysis, and the polymorphic microsatellite markers highly associated with vasculitis in each tissue were determined as vasculitis susceptibility loci.

RESULTS

A susceptibility locus with significant linkage to vasculitis of main branches of the aorta was mapped on chromosome 4 at D4Mit213 (map position 13.3cM) selectively in males, while vasculitis of medium-sized arteries in the lower limbs was mapped to different chromosomes: at D8Mit31 on chromosome 8 (map position 33.0) selectively in females and at D5Mit36 on chromosome 5 (map position 65.0). All of these were different from the previously defined loci governing susceptibility to vasculitis involving the kidneys.

CONCLUSION

Systemic vasculitis in MRL/lpr mice is genetically controlled with cumulative effects of multiple gene loci, each of which has tissue specificity.

Severe hypercholesterolemia, impaired fat tolerance, and advanced atherosclerosis in mice lacking both low density lipoprotein receptor-related protein 5 and apolipoprotein E

LDL receptor-related protein 5 (LRP5) plays multiple roles, including embryonic development and bone accrual development. Recently, we demonstrated that LRP5 is also required for normal cholesterol metabolism and glucose-induced insulin secretion. To further define the role of LRP5 in the lipoprotein metabolism, we compared plasma lipoproteins in mice lacking LRP5, apolipoprotein E (apoE), or both (apoE;LRP5 double knockout). On a normal chow diet, the apoE;LRP5 double knockout mice (older than 4 months of age) had approximately 60% higher plasma cholesterol levels compared with the age-matched apoE knockout mice. In contrast, LRP5 deficiency alone had no significant effects on the plasma cholesterol levels. High performance liquid chromatography analysis of plasma lipoproteins revealed that cholesterol levels in the very low density lipoprotein and low density lipoprotein fractions were markedly increased in the apoE;LRP5 double knockout mice. There were no apparent differences in the pattern of apoproteins between the apoE knockout mice and the apoE;LRP5 double knockout mice. The plasma clearance of intragastrically loaded triglyceride was markedly impaired by LRP5 deficiency. The atherosclerotic lesions of the apoE;LRP5 double knockout mice aged 6 months were approximately 3-fold greater than those in the age-matched apoE-knockout mice. Furthermore, histological examination revealed highly advanced atherosclerosis, with remarkable accumulation of foam cells and destruction of the internal elastic lamina in the apoE;LRP5 double knockout mice. These data suggest that LRP5 mediates both apoE-dependent and apoE-independent catabolism of plasma lipoproteins.

Antagonist of secondary lymphoid-tissue chemokine (CCR ligand 21) prevents the development of chronic graft-versus-host disease in mice

The use of receptor antagonists for chemokines is an alternative approach to blocking chemokine actions and has the potential to provide novel therapeutics. We determined the receptor antagonist properties of murine N-terminally truncated secondary lymphoid tissue chemokine (SLC)/6Ckine/CCR ligand 21 analogs and evaluated the preventive effects of SLC antagonists on chronic graft-vs-host disease (GVHD) in a murine model by blocking the homing of donor CCR7-expressing T cells into the recipient's lymphoid organs. SLC analogs truncated >4 aa residues from the N terminus showed a loss of chemotaxis and Ca2+ influx of CCR7-expressing cells and also inhibited SLC-stimulated chemotaxis and SLC-induced Ca2+ influx completely. To determine whether SLC antagonist inhibits the development of chronic GVHD, chronic GVHD was induced by injecting DBA/2 spleen cells into (C57BL/6 x DBA/2) F1 mice. Total numbers of spleen cells and host B cells, serum levels of IgE, and of total IgG and IgG1 of anti-DNA Abs in SLC antagonist-treated GVHD mice were significantly lower than those in control PBS-treated GVHD mice. This was due to a reduction in the levels of activated donor CD4+ T cells and a decrease in IL-4 production, resulting in a reduction in the numbers of activated host B cells. Therefore, our results suggest that SLC antagonist has beneficial effects for the prevention of chronic GVHD.

[An autopsy case of massive hemoptysis in systemic sarcoidosis with pulmonary granulomatous arteritis]

A 49-year-old female was admitted to our hospital because of worsening of congestive heart failure on November 2000 in a state after insertion of permanent pacemaker for complete atrioventricular block in 1986, followed by a clinical history of chronic heart failure due to dilated cardiomyopathy. After admission, her general condition had been improved, but, she had massive hemoptysis suddenly and died on February 2001. At autopsy, noncaseating granulomas were observed scattering in lungs, liver and spleen, not associated with any infectious lesions, therefore indicating systemic sarcoidosis. In lungs, granulomatous arteritis in small- and medium-sized muscular arteries associated with disputation of the media and elastic laminae were observed, suggesting the direct cause of hemoptysis. This is the extremely rare case of pulmonary arteritis with systemic sarcoidosis resulting the death from massive hemoptysis.

[Analysis of human cytomegalovirus infection of an autopsy case of dermatomyositis with rapidly progressive interstitial pneumonia: the possible correlation between the viral genome and its related protein on the pathogenesis]

We describe a case of a 61-year-old woman with amyopathic dermatomyositis (ADM), who developed rapidly progressive interstitial pneumonia and died of respiratory failure. An autopsy revealed interstitial pneumonia with diffuse alveolar damage, associated with infiltration of T cells, mostly positive for CD 8. The alveolar lining epithelial cells manifested the remarkable expression of immediate early/early antigen of human cytomegalovirus (HCMV). Moreover, the extract of the lung was transmittable of HCMV infection to cultured human embryo-fibroblasts in vitro. On the other hand, in the semi-quantitative analysis of HCMV genome, using laser-assisted microdissection, followed by PCR method, the genomic DNA in the alveolar lining epithelial cells was little detected in this case, although it was remarkable in the case of immunodeficiency with cytomegalovirus pneumonia. This case may be important to know the role of the immune response of host to HCMV infection on the development of rapidly progressive interstitial pneumonia.

Suppression of experimental lupus nephritis by aberrant expression of the soluble E-selectin gene

Circulating leukocytes, particularly neutrophils and monocytes, are important effector cells in the induction of many forms of glomerulonephritis. Adhesion molecules, especially selectins, are also thought to be critical for the development of this disease. We examined the possible suppressive effect of soluble E-selectin on the development of experimental lupus nephritis induced by the injection of a hybridoma clone (2B11.3) derived from an MRL/MpJ-lpr/lpr lupus mouse. This clone produces IgG3 antibodies that induce severe proliferative glomerulonephritis resembling lupus nephritis when injected into normal mice. Transgenic mice with a soluble E-selectin gene were injected intraperitoneally with the hybridoma cells and histopathologically examined on day 15. As a result, the development of glomerulonephritis was significantly suppressed. This suppression was characterized by fewer inflammatory cell infiltrates, compared with non-transgenic litter mates, despite the fact that there were no remarkable differences in immunoglobulin deposits or expression of E-selectin between the two groups. These findings suggest that by controlling inflammatory cell infiltration, soluble E-selectin plays a preventative role in the development of a particular type of lupus nephritis.

Experimental lupus nephritis in severe combined immunodeficient (SCID) mice: remodelling of the glomerular lesions by bystander IgM antibodies

MRL/Mp-lpr/lpr (MRL/lpr) mice develop glomerular lesions with regular variations in their histopathological manifestations, similar to those in lupus nephritis. These lesions are mainly either cell-proliferative or wire loop-like and are associated with glomerular deposits of immunoglobulins, most frequently IgG and IgM. We previously established a nephritogenic IgG3-producing hybridoma clone, B1, from an MRL/lpr mouse, which induces only a 'wire loop-like' type of glomerular lesion when injected into SCID mice. Injection of SCID mice with an anti-trinitrophenyl IgM antibody-producing hybridoma clone, Sp6, following injection of the B1 clone, however, resulted in the development of a 'cell-proliferative' type of glomerular lesion, associated with an accumulation of both antibodies in glomeruli. This accumulation occurred even though Sp6 IgM antibodies did not react with B1 IgG3 antibodies and vice versa. A mutant clone of Sp6, T/13microE/3.1, which produces antibodies deficient in C1q binding, produced a similar effect as that of the Sp6 clone, i.e. 'cell-proliferative' lesions. Again the B1 antibodies did not react with T/13microE/3. 1-IgM antibodies and vice versa. We therefore conclude that bystander IgM antibodies contribute to the remodelling of glomerular lesions in situ, following glomerular injury by the nephritogenic antibodies.

[An autopsy case of aortitis resulting in a tear of the aortic valve due to a rupture of the aneurysm of Valsalva's sinus]

A 43-year-old man was admitted to a hospital because of acute dyspnea and nocturnal orthopnea. Echocardiogram and chest CT showed the dilation of thoracic aorta from the root to ascending portion. On the third hospital day, he died suddenly. At autopsy, the cause of death was indicated to be a tear of an aortic valve due to a rupture of the aneurysm of Valsalva's sinus, followed by acute aortic regurgitation and acute cardiac insufficiency. Histopathological findings of thoracic aorta revealed mesoaortitis, characterized by patchy destruction of the media with a moth-eaten appearance of the medial elastic laminae and a microgranuloma formation, a perivascular mononuclear cell infiltration of the vasa vasorum, and a fibrous thickening of the intima and adventitia. However, there were no abnormalities in main branches of aorta and abdominal aorta, and no systemic vasculitis. This case is a rare one in the clinical course, and may be important to be differentiated from other cases with aortitis, especially Takayasu arteritis and syphilitic aortitis.

Genetic dissection of the complex pathological manifestations of collagen disease in MRL/lpr mice

An MRL strain of mice bearing a Fas-deletion mutant gene, lpr, MRL/MpJ-lpr/lpr (MRL/lpr) develops collagen disease involving vasculitis, glomerulonephritis, arthritis and sialoadenitis, each of which has been studied as a model for polyarteritis, lupus nephritis, rheumatoid arthritis and Sjögren's syndrome, respectively. Development of such lesions seems dependent on host genetic background since the congenic C3H/HeJ-lpr/lpr (C3H/lpr) mice rarely develop them. To identify the gene loci affecting each lesion, a genetic dissection of these complex pathological manifestations was carried out. First, histopathological features in MRL/lpr, C3H/lpr, (MRL/lpr x C3H/lpr) F1 intercross, and MRL/lpr x (MRL/lpr x C3H/lpr) F1 backcross mice were analyzed. Genomic DNA of the backcross mice were subjected to association studies by Chi-squared analysis for determining which polymorphic microsatellite locus occurs at higher frequency among affected compared to unaffected individuals for each lesion. As a result, gene loci recessively associated with each lesion were mapped on different chromosomal positions. We concluded that each of these lesions in MRL/lpr mice is under the control of a different set of genes, suggesting that the complex pathological manifestations of collagen disease result from polygenic inheritance.

Expression and characterization of a very low density lipoprotein receptor variant lacking the O-linked sugar region generated by alternative splicing

The very low density lipoprotein receptor (VLDLR) gene contains an exon encoding a region of clustered serine and threonine residues immediately outside the membrane-spanning sequence, and this region has been proposed to be the site of clustered O-linked carbohydrate chains. Two forms of VLDLR transcripts, with and without the O-linked sugar region, are generated through alternative splicing. Reverse transcription polymerase chain reaction with RNAs from various rabbit tissues revealed that the VLDLR transcript with the O-linked sugar region (type-1 VLDLR) is the major transcript in heart and muscle, while the VLDLR transcript without the O-linked sugar region (type-2 VLDLR) predominates in non-muscle tissues, including cerebrum, cerebellum, kidney, spleen, adrenal gland, testis, ovary, and uterus. Hamster fibroblasts expressing type-2 VLDLR bound with relatively low affinity to beta-migrating very low density lipoprotein compared with type-1 VLDLR-transfected cells. In contrast, the internalization, dissociation, and degradation of the ligand were not significantly impaired in either type of VLDLR-transfected cell. The receptor proteins in type-2 VLDLR-transfected cells underwent rapid degradation and accumulated in the culture medium, while those in type-1 VLDLR-transfected cells were stable and resistant to proteolytic cleavage. Analysis of the O-linked sugars of both types of transfected cells suggested that the O-linked sugar region is the major site for O-glycosylation.

Rheumatic diseases in an MRL strain of mice with a deficit in the functional Fas ligand

OBJECTIVE

To characterize Fas antigen expression on the cell surface, and to determine the effect of this expression in rheumatic diseases using a newly established gld-congenic MRL strain of mice (MRL/gld), which is defective in its functional Fas ligand (Fas-L).

METHODS

Flow cytometric analyses of lymphoid cells and macrophages were performed using anti-Fas and other cell surface markers. Histopathologic manifestations were examined using immunochemistry and light and electron microscopy. Serum levels of IgG and anti-DNA antibodies were measured by single radial immunodiffusion and enzyme-linked immunosorbent assay, respectively.

RESULTS

MRL/gld mice developed systemic lymphadenopathy with an accumulation of Thy1.2+, B220+ and CD4-, CD8- T cells, which both express the Fas antigen. Splenic B cells positive for surface IgM and/or surface IgD, and resident peritoneal macrophages exhibited up-regulated expression of the Fas antigen, at much higher levels than those observed in MRL/MpJ-+/+ (MRL/+) mice. Forms of rheumatic disease were observed in these mice, although not in C3H/HeJ-gld/gld mice. These forms included diffuse glomerulonephritis, granulomatous arteritis, and arthritis, and were associated with the infiltration of mononuclear cells expressing the Fas antigen. Serum levels of IgG and anti-DNA antibodies were significantly increased in MRL/gld mice compared with MRL/+ mice.

CONCLUSION

Rheumatic disease was generated by the gld gene in mice with an MRL background, as it is by the lpr gene, which is a Fas deletion mutant, associated with autoimmune traits. Rheumatic disease in this MRL strain was initiated by an incapacity for Fas/Fas-L-induced apoptosis, resulting in the development of autoimmunity and allowing for a persistent immune response in the affected lesions.

Arteritis in a novel congenic strain of mice derived from MRL/Lpr lupus mice: genetic dissociation from glomerulonephritis and limited autoantibody production

An MRL/Mp strain of mice bearing the Fas deletion mutant gene, lpr (MRL/lpr), spontaneously develop systemic vasculitis and glomerulone phritis in the same individual, and both have been thought to be associated with an increase in circulating immune complexes and autoantibodies. However, the genetic basis of these diseases is poorly understood. A novel recombinant congenic mouse strain, McH5-lpr/lpr, which was established by rearrangement of the genetic background of MRL/lpr mice by hybridization with C3H/HeJ-lpr/lpr mice, developed severe granulomatous polyarteritis, as did the MRL/lpr strain, but not glomerulonephritis. Serum levels of anti-DNA and anti-myeloperoxidase antibodies in these mice were significantly reduced, as compared with MRL/lpr mice, although rheumatoid factors were not. These results indicate that each of these two diseases, arteritis and glomerulonephritis, is under the control of different background gene(s), suggesting a different pathological basis of these diseases, and that anti-DNA and anti-myeloperoxidase autoantibodies appear to have a limited pathogenic role in granulomatous arteritis in the mouse strain described.

Role of macrophages in the development of arteritis in MRL strains of mice with a deficit in Fas-mediated apoptosis

The lpr and gld genes have been shown to encode the Fas antigen deletion mutant and the Fas ligand (FasL) mutant, respectively. An MRL strain of mice bearing the gld gene was observed to spontaneously develop granulomatous arteritis, similar to that in mice bearing the lpr gene, indicating that arteritis in this strain is due to an inefficient Fas-FasL interaction resulting in an incapacity for Fas-mediated apoptosis. The arterial lesions in both strains were characterized by a remarkable perivascular accumulation of activated macrophages bearing Mac-2 antigen, following the infiltration of CD4+ cells, and this resulted in the destruction of the arterial wall. Almost all of these infiltrating cells were Fas-positive, as determined in MRL/gld mice. Macrophage colony-stimulating factor (M-CSF), which is present at increased levels in MRL/lpr mice, but not in MRL/Mp- +/+ (MRL/+) mice, induced the expression of Mac-2 antigen and Fas antigen on spleen adherent cells of MRL/+ mice. Moreover, continuous infusion of M-CSF into the peritoneal cavity of subcutis of MRL/+ mice induced the release of oxygen radicals of peritoneal macrophages or granuloma formation associated with the massive accumulation of Mac-2+ cells, respectively. These findings suggest that macrophages in these mice, which may be activated by M-CSF and may avoid Fas-mediated apoptosis, play a critical role as effector cells in the destruction of arterial wall.

Vascular lesions in mice with a deficit in Fas-mediated apoptosis and their transfer

The lpr and gld genes are thought to result in an incapacity for Fas-mediated apoptosis of T and B cells and the development of subsequent autoimmune disease. A newly established gld-congenic strain of mice, MRL/MpTn-gld/gld (MRL/gld), was found to develop vascular lesions involving arteritis and glomerulonephritis (GN), which were similar to those observed in the MRL/Mp-lpr/lpr (MRL/lpr) strain. However, comparative studies with a C3H/HeJ strain bearing lpr or gld revealed that these lesions developed only in mice with an MRL background. We were successful in transferring GN to normal MHC-compatible gld/gld and irradiated +/+ mice by bone marrow cells of MRL/gld mice, but were unsuccessful using those of C3H/gld mice. Transfer of arteritis, however, was only successful in mice with an MRL background. Nephritogenic monoclonal antibodies obtained from an MRL/lpr and an MRL/gld mouse were shown to be bone marrow-derived and rich in clonal diversity, and at least two of these were capable of causing glomerular injury by different mechanisms. Development of GN and systemic arteritis in MRL/lpr and MRL/gld mice will be dependent not only on their incapacity for Fas-mediated apoptosis but also on bone marrow cells and peripheral cells with intrinsic defects.

[An autopsy case of segmental mediolytic arteritis (SMA) accompanied with microscopic polyarteritis nodosa]

Segmental Mediolytic Arteritis (SMA) is a very rare arterial lesion which is limited in adults to the involvement of the intra-abdominal muscular arteries. The pathology is characterized by segmental disruption of the arterial media which leads segmental mediolysis, with subsequent dissecting aneurysm or rupture. A 73-year-old man was admitted to a hospital because of high fever, general fatigue and weight loss. These symptoms were resistant to antibiotic therapy, and soon after, renal insufficiency developed. Three months after the onset of symptoms, he died suddenly of hemorrhagic shock. Autopsy revealed rupture of the splenic artery and systemic necrotizing arteritis in the small-sized arteries of liver, pancreas and kidneys, as well as in the connective tissues around the adrenal glands. Histopathology of the splenic artery was consistent with SMA, and that of the systemic vascular lesions, with microscopic polyarteritis nodosa. Focal glomerular lesions characteristic of crescentic and/or granulomatous glomerulonephritis were present. A developmental mechanism for SMA is discussed with respect to this case together with a review of previous reports of this disease.

[Animal models for intractable vasculitis: significance of genetic background]

Almost all of intractable vasculitis have been thought to develop mainly in immunological mechanisms, based on the data from several animal models previously established. Serum sickness models, microbe-induced models and others have contributed to supporting this idea. These models have furthermore indicated that vasculitis could be generated by exogenous factors in normal individuals, and that vasculitis might be explained in monism. However, recent studies in murine lupus suggest that intractable vasculitis requires endogenous factors involving retroviruses and/or genetic background under the control of polygene system. In this review, although not comprehensive, significance of background genes in vasculitis will be focused.

Observation of perturbations in a lumped-element model of the vocal folds with application to some pathological cases

In this paper a mass-spring model is developed that is a hybrid of the two-mass and the longitudinal string models, proposed by Ishizaka and Flanagan [Bell Sys. Tech. J. 51, 1233-1268 (1972)] and Titze [Phonetica 28, 129-170 (1973)], respectively. The model is used to simulate the vibratory motion of both the normal and asymmetric vocal folds. Mouth-output pressure, lateral tissue displacement, phase plots, and energy diagrams are presented to demonstrate the interaction between vocal fold tissue and the aerodynamic flow between the folds. The results of the study suggest that this interaction is necessary for sustained large amplitude oscillation because the flow supplies the energy lost by the tissue damping. Tissue mass and stiffness were varied locally or uniformly. Decreased stress in the longitudinal string tension produced subharmonic and chaotic vibrations in the displacement, velocity and acceleration phase diagrams. Similar vibratory characteristics also appeared in pathological speech data analyzed using time domain jitter and shimmer measures and a harmonics-to-noise ratio metric. The subharmonics create an effect that has been perceptually described as diplophonia.

Identification of metallic spheroids by classification of their electromagnetic induction responses

An investigation into the feasibility of applying pattern recognition concepts to the classification of metallic objects by their electromagnetic induction responses was performed. The effect on the response of a limited set of steel spheroids due to various factors such as object shape, size, and orientation was examined and a pattern recognition scheme based on these results was proposed. Implementation of the scheme involved the development of a novel extension to the nearest mean vector type of classifier in which the concept of the class mean as a point in feature space was generalized to be a curve. The resultant pattern recognition scheme was tested on a representative test set which included 815 responses, corresponding to 104 variations in object and orientation. A success rate of greater than 96 percent was achieved. It is noted that the classifier extension developed provides a viable approach to classification of responses that very continuously with respect to a single parameter.