MAFB in Macrophages Regulates Prostaglandin E2-Mediated Lipid Mediator Class Switch through ALOX15 in Ischemic Acute Kidney Injury.

Monocytes and macrophages express the transcription factor MAFB (V-maf musculoaponeurotic fibrosarcoma oncogene homolog B) and protect against ischemic acute kidney injury (AKI). However, the mechanism through which MAFB alleviates AKI in macrophages remains unclear. In this study, we induced AKI in macrophage lineage-specific Mafb-deficient mice (C57BL/6J) using the ischemia-reperfusion injury model to analyze these mechanisms. Our results showed that MAFB regulates the expression of Alox15 (arachidonate 15-lipoxygenase) in macrophages during ischemic AKI. The expression of ALOX15 was significantly decreased at the mRNA and protein levels in macrophages that infiltrated the kidneys of macrophage-specific Mafb-deficient mice at 24 h after ischemia-reperfusion injury. ALOX15 promotes the resolution of inflammation under acute conditions by producing specialized proresolving mediators by oxidizing essential fatty acids. Therefore, MAFB in macrophages promotes the resolution of inflammation in ischemic AKI by regulating the expression of Alox15. Moreover, MAFB expression in macrophages is upregulated via the COX-2/PGE2/EP4 pathway in ischemic AKI. Our in vitro assay showed that MAFB regulates the expression of Alox15 under the COX-2/PGE2/EP4 pathway in macrophages. PGE2 mediates the lipid mediator (LM) class switch from inflammatory LMs to specialized proresolving mediators. Therefore, MAFB plays a key role in the PGE2-mediated LM class switch by regulating the expression of Alox15. Our study identified a previously unknown mechanism by which MAFB in macrophages alleviates ischemic AKI and provides new insights into regulating the LM class switch in acute inflammatory conditions.

Plasma Globotriaosylsphingosine and α-Galactosidase A Activity as a Combined Screening Biomarker for Fabry Disease in a Large Japanese Cohort.

Fabry disease is an X-linked disorder of α-galactosidase A (GLA) deficiency. Our previous interim analysis (1 July 2014 to 31 December 2015) revealed plasma globotriaosylsphingosine as a promising primary screening biomarker for Fabry disease probands. Herein, we report the final results, including patients enrolled from 1 January to 31 December 2016 for evaluating the potential of plasma globotriaosylsphingosine and GLA activity as a combined screening marker. We screened 5691 patients (3439 males) referred from 237 Japanese specialty clinics based on clinical findings suggestive of Fabry disease using plasma globotriaosylsphingosine and GLA activity as primary screening markers, and GLA variant status as a secondary screening marker. Of the 14 males who tested positive in the globotriaosylsphingosine screen (≥2.0 ng/mL), 11 with low GLA activity (<4.0 nmol/h/mL) displayed GLA variants (four classic, seven late-onset) and one with normal GLA activity and no pathogenic variant displayed lamellar bodies in affected organs, indicating late-onset biopsy-proven Fabry disease. Of the 19 females who tested positive in the globotriaosylsphingosine screen, eight with low GLA activity displayed GLA variants (six classic, two late-onset) and five with normal GLA activity displayed a GLA variant (one classic) and no pathogenic variant (four late-onset biopsy-proven). The combination of plasma globotriaosylsphingosine and GLA activity can be a primary screening biomarker for classic, late-onset, and late-onset biopsy-proven Fabry disease probands.

Literature review of allograft adenovirus nephritis and a case presenting as mass lesions in a transplanted kidney without symptoms of urinary tract infection or acute kidney injury.

Adenovirus (AdV) infection is a common complication in bone marrow/hematopoietic stem cell transplant and solid organ transplant recipients. AdV infection usually presents as hemorrhagic cystitis, but sometimes it can progress to acute kidney injury showing AdV nephritis (AdVN). We present the case of a 52-year-old Japanese female who had received a living kidney transplantation (KT) from her husband. At 21 months post-KT, the patient presented with a fever, but no renal dysfunction and no abnormal urine findings. A contrast-enhanced computed tomography (CT) scan revealed a few mass lesions with hypoperfusion in the transplanted kidney. An enhanced CT-guided biopsy targeting one of these lesions revealed a necrotizing tubulointerstitial nephritis suggesting AdVN. The polymerase chain reaction tests for ADV were negative in a urine sample but positive in the sera and the frozen kidney biopsy samples. AdVN can manifest as an unusual pattern of acute lobar nephritis/acute focal bacterial nephritis-like localization without symptoms of acute kidney injury or urinary tract infection. Enhanced CT can provide clues for clinical diagnosis.

Ratio of serum creatinine to cystatin C is related to leg strength in predialysis CKD patients.

BACKGROUND AND OBJECTIVES: Chronic kidney disease (CKD) patients have lower levels of physical function. Especially, leg strength is important for daily living and preventing falls. However, physical function screenings are difficult to perform at clinical sites. To find clinically useful method to evaluate physical function in predialysis CKD patients, we tried to evaluate the relationship between the ratio of serum creatinine to serum cystatin C (Cre/CysC), and knee extensor muscle strength/body weight (KEMS) which reflects their leg strength. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: We recruited 147 outpatients with CKD (87 men; mean age, 61.6 ± 9.8 years; mean eGFRcreat, 40.7 ± 12.9 mL/min/1.73m2) in this cross-sectional study. KEMS was assessed using a wire strain gauge dynamometer. Skeletal muscle mass and body fat mass were assessed by bioelectrical impedance analysis. RESULTS: The mean value of Cre/CysC was 1.01 ± 0.18. The mean value of KEMS was 1.60 ± 0.47 Nm/kg. In multivariate linear regression analysis, skeletal muscle mass (p < 0.01), body fat mass (p < 0.01), hemoglobin (p = 0.01), and Cre/CysC (p < 0.01) was independently related to KEMS. The correlation between Cre/CysC and KEMS is stronger in high quantile of Cre/CysC. CONCLUSIONS: In predialysis CKD patients, KEMS showed lower as CKD stage advanced. Cre/CysC is significantly related to KEMS independently. Cre/CysC may be an alternative marker for leg strength in CKD patients and even more valuable to utilize in cases with high Cre/CysC.

Transcription factor MafB in podocytes protects against the development of focal segmental glomerulosclerosis.

Focal segmental glomerulosclerosis (FSGS) is a common cause of steroid-resistant nephrotic syndrome. Spontaneous remission of FSGS is rare and steroid-resistant FSGS frequently progresses to renal failure. Many inheritable forms of FSGS have been described, caused by mutations in proteins that are important for podocyte function. Here, we show that a basic leucine zipper transcription factor, MafB, protects against FSGS. MAFB expression was found to be decreased in the podocytes of patients with FSGS. Moreover, conditional podocyte-specific MafB-knockout mice developed FSGS with massive proteinuria accompanied by depletion of the slit diaphragm-related proteins (Nphs1 and Magi2), and the podocyte-specific transcription factor Tcf21. These findings indicate that MafB plays a crucial role in the pathogenesis of FSGS. Consistent with this, adriamycin-induced FSGS and attendant proteinuria were ameliorated by MafB overexpression in the podocytes of MafB podocyte-specific transgenic mice. Thus, MafB could be a new therapeutic target for FSGS.

Phenotypic analysis of mice carrying human-type MAFB p.Leu239Pro mutation.

The transcription factor, MafB, plays important role in the differentiation and functional maintenance of various cells and tissues, such as the inner ear, kidney podocyte, parathyroid gland, pancreatic islet, and macrophages. The rare heterozygous substitution (p.Leu239Pro) of the DNA binding domain in MAFB is the cause of Focal Segmental Glomerulosclerosis associated with Duane Retraction Syndrome, which is characterized by impaired horizontal eye movement due to cranial nerve maldevelopment in humans. In this research, we generated mice carrying MafB p.Leu239Pro (Mafbmt/mt) and retrieved their tissues for analysis. As a result, we found that the phenotype of Mafbmt/mt mouse was similar to that of the conventional Mafb deficient mouse. This finding suggests that the Leucine residue at 239 in the DNA binding domain plays a key role in MafB function and could contribute to the diagnosis or development of treatment for patients carrying the MafB p.Leu239Pro missense variant.

Mice lacking core 1-derived O-glycan in podocytes develop transient proteinuria, resulting in focal segmental glomerulosclerosis.

The glomerular filtration barrier is composed of podocytes, glomerular basement membrane, and endothelial cells. Disruption of these structures causes several glomerular injuries, such as focal segmental glomerulosclerosis (FSGS). The surface of podocyte apical membranes is coated by negatively charged sialic acids on core 1-derived mucin-type O-glycans. Here, we aimed to investigate the physiological role of core 1-derived O-glycans in the podocytes using adult mice lacking podocyte-specific core 1-derived O-glycans (iPod-Cos). iPod-Cos mice exhibited early and transient proteinuria with foot process effacements and developed typical FSGS-like disease symptoms. To identify the key molecules responsible for the FSGS-like phenotype, we focused on podocalyxin and podoplanin, which possess mucin-type O-glycans. Expression and localization of podocalyxin did not change in iPod-Cos glomeruli. Besides, western blot analysis revealed significantly lower levels of intact podocalyxin in isolated glomeruli of iPod-Cos mice, and high levels of processed forms in iPod-Cos glomeruli, as compared to that in control glomeruli. Conversely, podoplanin mRNA, and protein levels were lower in iPod-Cos mice than in control mice. These results demonstrated that core 1-derived O-glycan on podocytes is required for normal glomerular filtration and may contribute to the stable expression of podocalyxin and podoplanin.

Transcription factor MafB may play an important role in secondary hyperparathyroidism.

The transcription factor MafB is essential for development of the parathyroid glands, the expression of which persists after morphogenesis and in adult parathyroid glands. However, the function of MafB in adult parathyroid tissue is unclear. To investigate this, we induced chronic kidney disease (CKD) in wild-type and MafB heterozygote (MafB+/-) mice by feeding them an adenine-supplemented diet, leading to secondary hyperparathyroidism. The elevated serum creatinine and blood urea nitrogen levels in heterozygous and wild-type mice fed the adenine-supplemented diet were similar. Interestingly, secondary hyperparathyroidism, characterized by serum parathyroid hormone elevation and enlargement of parathyroid glands, was suppressed in MafB+/- mice fed the adenine-supplemented diet compared to similarly fed wild-type littermates. Quantitative RT-PCR and immunohistochemical analyses showed that the increased expression of parathyroid hormone and cyclin D2 in mice with CKD was suppressed in the parathyroid glands of heterozygous CKD mice. A reporter assay indicated that MafB directly regulated parathyroid hormone and cyclin D2 expression. To exclude an effect of a developmental anomaly in MafB+/- mice, we analyzed MafB tamoxifen-induced global knockout mice. Hypocalcemia-stimulated parathyroid hormone secretion was significantly impaired in MafB knockout mice. RNA-sequencing analysis indicated PTH, Gata3 and Gcm2 depletion in the parathyroid glands of MafB knockout mice. Thus, MafB appears to play an important role in secondary hyperparathyroidism by regulation of parathyroid hormone and cyclin D2 expression. Hence, MafB may represent a new therapeutic target in secondary hyperparathyroidism.

A mutation in transcription factor MAFB causes Focal Segmental Glomerulosclerosis with Duane Retraction Syndrome.

Focal segmental glomerulosclerosis (FSGS) is a leading cause of end-stage renal disease in children and adults. Genetic factors significantly contribute to early-onset FSGS, but the etiologies of most adult cases remain unknown. Genetic studies of monogenic syndromic FSGS exhibiting extra-renal manifestations have uncovered an unexpected biological role for genes in the development of both podocytes and other cellular lineages. To help define these roles, we studied two unrelated families with FSGS associated with Duane Retraction Syndrome, characterized by impaired horizontal eye movement due to cranial nerve malformation. All four affected individuals developed FSGS and Duane Retraction Syndrome in their first to second decade of life, manifested as restricted abduction together with globe retraction and narrowed palpebral fissure on attempted adduction. Hypoplasia of the abducens nerves and hearing impairment occurred in severely affected individuals. Genetic analyses revealed that affected individuals harbor a rare heterozygous substitution (p.Leu239Pro) in MAFB, a leucine zipper transcription factor. Luciferase assays with cultured monocytes indicated that the substitution significantly reduced transactivation of the F4/80 promoter, the known MAFB recognition element. Additionally, immunohistochemistry indicated reduced MAFB expression in the podocytes of patients. Structural modeling suggested that the p.Leu239Pro substitution in the DNA-binding domain possibly interferes with the stability of the adjacent zinc finger. Lastly, podocytes in neonatal mice with p.Leu239Pro displayed impaired differentiation. Thus, MAFB mutations impair development and/or maintenance of podocytes, abducens neurons and the inner ear. The interactions between MAFB and regulatory elements in these developing organs are likely highly specific based on spatiotemporal requirements.

Anaemia is an essential complication of ANCA-associated renal vasculitis: a single center cohort study.

BACKGROUND: Anaemia is a common complication of patients with antineutrophil cytoplasmic antibody (ANCA)-associated renal vasculitis. Nevertheless, the cause and degree of such cases of anaemia have not been elucidated in detail. We aimed to investigate the prevalence, cause, pathogenesis of anaemia and the impact of anaemia on prognosis in patients with ANCA-associated renal vasculitis. METHODS: We identified 45 patients with ANCA-associated renal vasculitis that were clinically and/or histologically diagnosed and treated from 2003 to 2014 at University of Tsukuba Hospital. The relationships between anaemia and various clinicopathological findings were evaluated. RESULTS: At the time of diagnosis of ANCA-associated renal vasculitis, all patients showed anaemia, with a mean haemoglobin level of 7.5 ± 1.3 g/dL. Renal anaemia was diagnosed in 92% of patients, anaemia of chronic disease (ACD) in 56%, and anaemia due to hemorrhage in 20%. Next, the patients were divided into two groups according to anaemia severity: minimum haemoglobin (min Hb) < 7.5 (n = 24) and min Hb ≥ 7.5 (n = 21). A comparison of baseline characteristics showed that serum albumin, maximum serum creatinine, minimum estimated glomerular filtration rate (eGFR), serum cystatin C, and the area of tubulointerstitial damage were significantly different between the haemoglobin groups (p < 0.05). No significant intergroup differences were observed in iron-related or inflammation-related data. With regard to the relationship between anaemia severity and prognosis, patients in the min Hb < 7.5 group tended to have a lower eGFR. Anaemia severity was associated with markedly lower survival (Log-rank test, p = 0.03). CONCLUSIONS: In this cohort of patients with ANCA-associated renal vasculitis, all subjects exhibited anaemia. In regard to the cause and pathogenesis, the most prevalent form of anaemia was renal anaemia, not ACD, and a potential reason for the high prevalence of anaemia in our cohort may have been the interaction between renal anaemia and ACD. Moreover, anaemia severity was significantly associated with the degree of renal dysfunction and life prognosis.

O-linked glycosylation determines the nephritogenic potential of IgA rheumatoid factor.

Deficient glycosylation of O-linked glycans in the IgA1 hinge region is associated with IgA nephropathy in humans, but the pathogenic contribution of the underlying structural aberrations remains incompletely understood. We previously showed that mice implanted with cells secreting the class-switch variant 6-19 IgA anti-IgG2a rheumatoid factor, but not 46-42 IgA anti-IgG2a rheumatoid factor, develop glomerular lesions resembling IgA nephropathy. Because the levels of O-linked glycosylation in the hinge region and the structures of N-linked glycans in the CH1 domain differ in 6-19 IgA and 46-42 IgA, we determined the respective contributions of O- and N-linked glycans to the nephritogenic potential of the 6-19 IgA rheumatoid factor in mice. Wild-type 6-19 IgA secreted by implanted cells induced significant formation of glomerular lesions, whereas poorly O-glycosylated 6-19 IgA glycovariants or a 6-19 IgA hinge mutant lacking O-linked glycans did not. However, we observed no apparent heterogeneity in the structure of N-linked glycans attached to three different sites of the Fc regions of nephritogenic and non-nephritogenic 6-19 IgAs. Collectively, our data suggest a critical role of O-linked glycans attached to the hinge region in the development of IgA nephropathy-like GN induced by 6-19 IgA rheumatoid factor in mice.

Overexpression of Mafb in podocytes protects against diabetic nephropathy.

We previously showed that the transcription factor Mafb is essential for podocyte differentiation and foot process formation. Podocytes are susceptible to injury in diabetes, and this injury leads to progression of diabetic nephropathy. In this study, we generated transgenic mice that overexpress Mafb in podocytes using the nephrin promoter/enhancer. To examine a potential pathogenetic role for Mafb in diabetic nephropathy, Mafb transgenic mice were treated with either streptozotocin or saline solution. Diabetic nephropathy was assessed by renal histology and biochemical analyses of urine and serum. Podocyte-specific overexpression of Mafb had no effect on body weight or blood glucose levels in either diabetic or control mice. Notably, albuminuria and changes in BUN levels and renal histology observed in diabetic wild-type animals were ameliorated in diabetic Mafb transgenic mice. Moreover, hyperglycemia-induced downregulation of Nephrin was mitigated in diabetic Mafb transgenic mice, and reporter assay results suggested that Mafb regulates Nephrin directly. Mafb transgenic glomeruli also overexpressed glutathione peroxidase, an antioxidative stress enzyme, and levels of the oxidative stress marker 8-hydroxydeoxyguanosine decreased in the urine of diabetic Mafb transgenic mice. Finally, Notch2 expression increased in diabetic glomeruli, and this effect was enhanced in diabetic Mafb transgenic glomeruli. These data indicate Mafb has a protective role in diabetic nephropathy through regulation of slit diaphragm proteins, antioxidative enzymes, and Notch pathways in podocytes and suggest that Mafb could be a therapeutic target.

Health-related quality of life and prognosis in patients with chronic kidney disease: a 3-year follow-up study.

BACKGROUND: Chronic kidney disease (CKD) is a major global problem and is also associated with a decreased health-related quality of life (HRQOL). The aim of this study was to evaluate measured HRQOL based on the new CKD classification including proteinuria stage, and the effect of measured HRQOL on CKD progression and clinical outcomes over a 3-year period. METHODS: EuroQol (EQ-5D), a generic preference-based questionnaire, was administered to 537 CKD outpatients at the University of Tsukuba Hospital between November and December 2008. We evaluated disease progression in CKD patients including the incidence of end-stage kidney disease (ESKD), cardiovascular disease (CVD) and all-cause mortality over a 3-year follow-up period. RESULTS: The proportions progressing to the higher stages were 32.6, 20.0, 36.6, 39.5, and 45.8 % from glomerular filtration rate (GFR) stages (G) 1-4, respectively. The proportion progressing to ESKD (G5D) was 0.7 % from G2, 3.9 % from G3b, 20.8 % from G4 and 63.4 % from G5. The incidence of CVD and/or death was 1.2, 4.6, 4.9, 5.3, 8.3 and 21.1 % from G1-G5, respectively. The quality-adjustment weights at G4-5 were significantly lower than at G1-2 and the weights at proteinuria stage (A) 3 were significantly lower than at A1-2. The quality-adjustment weights of patients with events such as 50 % estimated GFR decline, dialysis, CVD, and/or death were significantly lower than those without events. CONCLUSION: We showed CKD progression and clinical outcomes over a 3-year period. Quality-adjustment weights in CKD patients were associated with not only disease progression such as initiation of dialysis treatment and incidence of CVD events and all-cause death, but also the level of proteinuria at baseline.

Overexpression of RORγt under control of the CD2 promoter induces polyclonal plasmacytosis and autoantibody production in transgenic mice.

Retinoic acid related orphan receptor gamma-t (RORγt) is known to be a master regulator of Th17-cell development. In this study, we generated RORγt-overexpressing transgenic (RORγt Tg) mice in which transgene expression was driven by the CD2 promoter, and found that these mice developed polyclonal plasmacytosis and autoantibody production. RORγt Tg mice were generated on a C57BL/6 background, and also were intercrossed with BALB/c mice. BALB/c F1 (BALB/F1) RORγt Tg mice developed massive polyclonal plasma-cytosis, and had shorter life spans. Splenomegaly and infiltration of plasma cells into the lung were observed. Hyperglobulinemia, anti-double-stranded DNA antibodies, anti-erythrocyte antibodies, and anti-platelet antibodies were detected in BALB/F1 RORγt Tg mice. In the present study, polyclonal plasmacytosis in BALB/F1 RORγt Tg mice appeared to be due to the induction of excessive IL-6 production by IL-17. We detected increased numbers of CD11b(+) cells that produced IL-6. We also generatedIL-6-deficient RORγt Tg BALB/F1 background mice, which displayed high levels of serum IL-17, but did not develop severe hyperglobulinemia. Excessive IL-6 production by several cell types, including macrophages, in BALB/F1 RORγt Tg mice, might effect the development of plasma-cytosis. These results suggest that RORγt plays important roles in the development of plasmacytosis and autoantibody production.

Podocyte-specific Transcription Factors: Could MafB Become a Therapeutic Target for Kidney Disease?

The increasing number of patients with chronic kidney disease (CKD) is being recognized as an emerging global health problem. Recently, it has become clear that injury and loss of glomerular visceral epithelial cells, known as podocytes, is a common early event in many forms of CKD. Podocytes are highly specialized epithelial cells that cover the outer layer of the glomerular basement membrane. They serve as the final barrier to urinary protein loss through the formation and maintenance of specialized foot-processes and an interposed slit-diaphragm. We previously reported that the transcription factor MafB regulates the podocyte slit diaphragm protein production and transcription factor Tcf21. We showed that the forced expression of MafB was able to prevent CKD. In this review, we discuss recent advances and offer an updated overview of the functions of podocyte-specific transcription factors in kidney biology, aiming to present new perspectives on the progression of CKD and respective therapeutic strategies.

Transcription factor c-Maf deletion improves streptozotocin-induced diabetic nephropathy by directly regulating Sglt2 and Glut2.

The transcription factor c-Maf has been widely studied and has been reported to play a critical role in embryonic kidney development; however, the postnatal functions of c-Maf in adult kidneys remain unknown as c-Maf-null C57BL/6J mice exhibit embryonic lethality. In this study, we investigated the role of c-Maf in adult mouse kidneys by comparing the phenotypes of tamoxifen-inducible (TAM-inducible) c-Maf-knockout mice (c-Maffl/fl; CAG-Cre-ERTM mice named "c-MafΔTAM") with those of c-Maffl/fl control mice, 10 days after TAM injection [TAM(10d)]. In addition, we examined the effects of c-Maf deletion on diabetic conditions by injecting the mice with streptozotocin, 4 weeks before TAM injection. c-MafΔTAM mice displayed primary glycosuria caused by sodium-glucose cotransporter 2 (Sglt2) and glucose transporter 2 (Glut2) downregulation in the kidneys without diabetes, as well as morphological changes and life-threatening injuries in the kidneys on TAM(10d). Under diabetic conditions, c-Maf deletion promoted recovery from hyperglycemia and suppressed albuminuria and diabetic nephropathy by causing similar effects as did Sglt2 knockout and SGLT2 inhibitors. In addition to demonstrating the potentially unique gene regulation of c-Maf, these findings highlight the renoprotective effects of c-Maf deficiency under diabetic conditions and suggest that c-Maf could be a novel therapeutic target gene for treating diabetic nephropathy.

Focal segmental glomerulosclerosis as a complication of hepatitis B virus infection.

Human hepatitis B virus (HBV) is well known as a cause of membranous nephropathy (MN). While the association of HBV infection with MN is strong, data regarding its association with other glomerular diseases are conflicting. Here, we report a case of focal segmental glomerulosclerosis (FSGS) with HBV infection. In this case, we have found HBV-DNA in urinary podocytes by real-time PCR methods. After the administration of anti-viral therapy, FSGS improved, paralleling the decreased level of HBV-DNA in podocytes. The refractory FSGS induced by HBV could be effectively treated with appropriate anti-viral agents.

Selective up-regulation of intact, but not defective env RNAs of endogenous modified polytropic retrovirus by the Sgp3 locus of lupus-prone mice.

Endogenous retroviruses are implicated in the pathogenesis of systemic lupus erythematosus (SLE). Because four different classes of endogenous retroviruses, i.e., ecotropic, xenotropic, polytropic, or modified polytropic (mPT), are expressed in mice, we investigated the possibility that a particular class of endogenous retroviruses is associated with the development of murine SLE. We observed >15-fold increased expression of mPT env (envelope) RNA in livers of all four lupus-prone mice, as compared with those of nine nonautoimmune strains of mice. This was not the case for the three other classes of retroviruses. Furthermore, we found that in addition to intact mPT transcripts, many strains of mice expressed two defective mPT env transcripts which carry a deletion in the env sequence of the 3' portion of the gp70 surface protein and the 5' portion of the p15E transmembrane protein, respectively. Remarkably, in contrast to nonautoimmune strains of mice, all four lupus-prone mice expressed abundant levels of intact mPT env transcripts, but only low or nondetectable levels of the mutant env transcripts. The Sgp3 (serum gp70 production 3) locus derived from lupus-prone mice was responsible for the selective up-regulation of the intact mPT env RNA. Finally, we observed that single-stranded RNA-specific TLR7 played a critical role in the production of anti-gp70 autoantibodies. These data suggest that lupus-prone mice may possess a unique genetic mechanism responsible for the expression of mPT retroviruses, which could act as a triggering factor through activating TLR7 for the development of autoimmune responses in mice predisposed to SLE.

A case of multicentric Castleman's disease with membranoproliferative glomerulonephritis type 3-like lesion.

Renal involvement is a significant complication of multicentric Castleman's disease (MCD) and various glomerular involvements have been reported. A 45-year-old Japanese man presented with persistent proteinuria, with lymphadenopathy and hypergammaglobulinemia. He had been diagnosed 4 years previously with MCD. As his renal impairment had progressed to renal failure, he underwent a renal biopsy. Histology revealed diffuse and global membranous lesions with large and heterogeneous epimembranous deposits. In addition, mesangial cell proliferation and focal extracapillary lesions were found. Under immunofluorescence, granular staining for anti-IgG, IgG1, IgG2 and IgA was strongly positive in the capillary loop, and weakly positive in the mesangium. As such, there was a diversity of histological features. Our perspective with regard to pathogenesis is that the formation of the immune-complex contributed to the membranoproliferative glomerulonephritis type 3-like lesion. This histological multiform with MCD is valuable for increasing our understanding of the mechanism for onset of immune-complex glomerular deposition and cellular proliferation of glomerulonephritis.

Anti-glomerular Basement Membrane Glomerulonephritis During the First Trimester of Pregnancy.

A 28-year-old woman was admitted during the eighth week of her pregnancy because her clinical course was consistent with rapid progressive glomerulonephritis (RPGN). Anti-glomerular basement membrane antibody (anti-GBM Ab) and myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA) were positive, and the anti-GBM Ab titer being extremely high. She was treated with hemodialysis, plasma exchange and prednisolone. She survived the illness; however, neither the fetus nor her kidney function could be rescued. She had human leukocyte antigen (HLA)-DRB1*1502:01, which differs from the DRB1*1501 associated with anti-GBM GN. When patients have particular symptoms, we should check the urine and serum creatinine to exclude RPGN, even in cases of pregnancy.