Abnormal glomerular basement membrane maturation impairs mesangial cell differentiation during murine postnatal nephrogenesis.

Although mesangial cell-glomerular basement membrane (GBM) connections play a key role in maintaining the glomerular capillary loop structure, information remains limited about how these connections are formed during glomerulogenesis. We have previously shown that weakened podocyte-GBM interactions owing to tensin 2 (Tns2) deficiency lead to abnormal GBM maturation during postnatal glomerulogenesis. Here, we investigated whether abnormal GBM maturation affected mesangial cell-GBM connections and mesangial cell differentiation. Histological analysis of the outer cortical glomeruli in Tns2-deficient mice revealed that GBM materials overproduced by stressed immature podocytes accumulated in the mesangium and interrupted the formation of mesangial cell-GBM connections, resulting in fewer capillary loops compared with that of normal glomeruli. In addition, expression of α-smooth muscle actin, an immature mesangial cell marker, persisted in mesangial cells of Tns2-deficient outer cortical glomeruli even after glomerulogenesis was completed, resulting in mesangial expansion. Furthermore, analysis of mouse primary mesangial cells revealed that mesangial cell differentiation depended on the type of extracellular matrix components to which the cells adhered, suggesting the participation of mesangial cell-GBM connections in mesangial cell differentiation. These findings suggest that abnormal GBM maturation affects mesangial cell differentiation by impairing mesangial cell-GBM connections.NEW & NOTEWORTHY Mesangial cell-glomerular basement membrane (GBM) connections play an important role in maintaining the structural integrity of the glomerular tuft. However, information remains scarce about how GBM maturation affects the formation of these connections during glomerular development. Here, we show that abnormal GBM maturation due to tensin 2 deficiency affects mesangial cell differentiation by impairing mesangial cell-GBM connections during postnatal glomerulogenesis.

Understanding women's choices for management of cervical intraepithelial neoplasia 2 (CIN2): Qualitative analysis of a randomised experimental study.

BACKGROUND: Active surveillance for cervical intraepithelial neoplasia 2 (CIN2) would allow time for most cases to regress naturally and in turn avoid potentially unnecessary and harmful treatment. AIM: To determine reasons for choosing active surveillance over surgery among women given a hypothetical diagnosis of CIN2. MATERIALS AND METHODS: Women residing in Australia aged 25-40 years with no prior diagnosis of cervical cancer, cervical abnormality CIN2 or above, and/or previous hysterectomy, were randomised to one of four identical hypothetical scenarios of testing human papillomavirus (HPV)-positive: high-grade cytology and a diagnosis of CIN2 that used alternate terminology to describe resolution of abnormal cells and/or inclusion of an overtreatment statement. Participants selected active surveillance or surgery after viewing the scenario and free-text reason/s for their choice were thematically analysed. RESULTS: Of the 1638 women randomised, 79% (n = 1293) opted for active surveillance. The most common reasons for choosing active surveillance included concerns about surgery and associated risks, preferring to 'wait and see', trusting the doctor's recommendations and having an emotional response toward surgery. For women who chose surgery, being risk-averse, addressing the issue straight away and perceiving surgery to be the better option for them were the most common themes identified. CONCLUSION: When presented with balanced information on the benefits and harms of different management options for CIN2 and given a choice, most women in this hypothetical situation chose active surveillance over surgery. Addressing women's concerns about active surveillance may open up the possibility that if deemed safe, it could be an acceptable alternative for women.

Tensin2 is important for podocyte-glomerular basement membrane interaction and integrity of the glomerular filtration barrier.

Tensin2 (Tns2), an integrin-linked protein, is enriched in podocytes within the glomerulus. Previous studies have revealed that Tns2-deficient mice exhibit defects of the glomerular basement membrane (GBM) soon after birth in a strain-dependent manner. However, the mechanisms for the onset of defects caused by Tns2 deficiency remains unidentified. Here, we aimed to determine the role of Tns2 using newborn Tns2-deficient mice and murine primary podocytes. Ultrastructural analysis revealed that developing glomeruli during postnatal nephrogenesis exhibited abnormal GBM processing due to ectopic laminin-α2 accumulation followed by GBM thickening. In addition, analysis of primary podocytes revealed that Tns2 deficiency led to impaired podocyte-GBM interaction and massive expression of laminin-α2 in podocytes. Our study suggests that weakened podocyte-GBM interaction due to Tns2 deficiency causes increased mechanical stress on podocytes by continuous daily filtration after birth, resulting in stressed podocytes ectopically producing laminin-α2, which interrupts GBM processing. We conclude that Tns2 plays important roles in the podocyte-GBM interaction and maintenance of the glomerular filtration barrier.

Essential Role of CARD14 in Murine Experimental Psoriasis.

Caspase recruitment domain family member 14 (CARD14) was recently identified as a psoriasis-susceptibility gene, but its immunological role in the pathogenesis of psoriasis in vivo remains unclear. In this study, we examined the role of CARD14 in murine experimental models of psoriasis induced by either imiquimod (IMQ) cream or recombinant IL-23 injection. In all models tested, the psoriasiform skin inflammation was abrogated in Card14-/- mice. Comparison of the early gene signature of the skin between IMQ-cream-treated Card14-/- mice and Tlr7-/-Tlr9-/- mice revealed not only their similarity, but also distinct gene sets targeted by IL-23. Cell type-specific analysis of these mice identified skin Langerinhigh Langerhans cells as a potent producer of IL-23, which was dependent on both TLR7 and TLR9 but independent of CARD14, suggesting that CARD14 is acting downstream of IL-23, not TLR7 or TLR9. Instead, a bone marrow chimera study suggested that CARD14 in radio-sensitive hematopoietic cells was required for IMQ-induced psoriasiform skin inflammation, controlling the number of Vγ4+ T cells producing IL-17 or IL-22 infiltrating through the dermis to the inflamed epidermis. These data indicate that CARD14 is essential and a potential therapeutic target for psoriasis.

C1r/C1s deficiency is insufficient to induce murine systemic lupus erythematosus.

C1s deficiency is strongly associated with the development of human systemic lupus erythematosus (SLE); however, the mechanisms by which C1s deficiency contributes to the development of SLE have not yet been elucidated in detail. Using ICR-derived-glomerulonephritis (ICGN) mouse strain that develops SLE and very weakly expresses C1s in the liver, we investigated the protective roles of C1s against SLE. A genetic sequence analysis revealed complete deletion of the C1s1 gene, a mouse homolog of the human C1s gene, with partial deletion of the C1ra and C1rb genes in the ICGN strain. This deletion led to the absence of C1r/C1s and a low level of C1q in the circulation. In order to investigate whether the C1r/C1s deficiency induces SLE, we produced a congenic mouse strain by introducing the deletion region of ICGN into the C57BL/6 strain. Congenic mice exhibited no C1r/C1s and a low level of C1q in the circulation, but did not have any autoimmune defects. These results suggest that C1r/C1s deficiency is not sufficient to drive murine SLE and also that other predisposing genes exist in ICGN mice.

Clinicopathological characteristics and rituximab addition to cytotoxic therapies in patients with rheumatoid arthritis and methotrexate-associated large B lymphoproliferative disorders.

AIMS: To analyse the clinicopathological characteristics and prognosis of 40 rheumatoid arthritis (RA) patients with methotrexate (MTX)-associated large B cell lymphoproliferative disorders (MTX-BLPD). METHODS AND RESULTS: Soluble interleukin 2 receptor titres (median 1500 U/ml) in 40 patients with MTX-BLPD were lower than those of 24 RA patients with non-MTX- associated (non-MTX) BLPD (5731 U/ml) and 15 with control diffuse large B cell lymphoma (DLBCL, 5918 U/ml) (P < 0.01). Using in-situ hybridization, Epstein-Barr virus (EBV) was detected in tumour cells of 25 of 40 RA patients with MTX-BLPD (63%). Immunohistologically, BCL2 expression was detected in 35% of patients with MTX-BLPD, which was lower than 93% of control DLBCL patients (P < 0.01). Eleven patients with EBV(+) MTX-BLPD (44%) showed remission after MTX withdrawal. In RA patients with clinical stage III/IV BLPD, 15 with rituximab (R)+ cytotoxic therapies pursued better prognosis than 10 with R- cytotoxic therapies (P < 0.05). Among the 15 patients, seven with MTX-BLPD showed better overall survival than nine control DLBCL patients (P < 0.01). CONCLUSIONS: In RA patients with MTX-BLPD, immunosuppression by MTX, EBV infection and low BCL2 expression in tumour cells may play roles in tumorigenesis and tumour regression. R+ cytotoxic therapies as well as MTX withdrawal were highly effective in these patients.

Trisomy 12 compromises the mesendodermal differentiation propensity of human pluripotent stem cells.

Trisomy 12 is one of the most frequent chromosomal abnormalities in cultured human pluripotent stem cells (hPSCs). Although potential oncogenic properties and augmented cell cycle caused by trisomy 12 have been reported, the consequences of trisomy 12 in terms of cell differentiation, which is the basis for regenerative medicine, drug development, and developmental biology studies, have not yet been investigated. Here, we report that trisomy 12 compromises the mesendodermal differentiation of hPSCs. We identified sublines of hPSCs carrying trisomy 12 after their prolonged culture. Transcriptome analysis revealed that these hPSC sublines carried abnormal gene expression patterns in specific signaling pathways in addition to cancer-related cell cycle pathways. These hPSC sublines showed a lower propensity for mesendodermal differentiation in embryoid bodies cultured in a serum-free medium. BMP4-induced exit from the self-renewal state was impaired in the trisomy 12 hPSC sublines, with less upregulation of key transcription factor gene expression. As a consequence, the differentiation efficiency of hematopoietic and hepatic lineages was also impaired in the trisomy 12 hPSC sublines. We reveal that trisomy 12 disrupts the genome-wide expression patterns that are required for proper mesendodermal differentiation.

Tenc1-deficient mice develop glomerular disease in a strain-specific manner.

BACKGROUND/AIMS: Tenc1 (also known as tensin2) is an integrin-associated focal adhesion molecule that is broadly expressed in mouse tissues including the liver, muscle, heart and kidney. A mouse strain carrying mutated Tenc1, the ICR-derived glomerulonephritis (ICGN) strain, develops severe nephrotic syndrome. METHODS: To elucidate the function of Tenc1 in the kidney, Tenc1(ICGN) was introduced into 2 genetic backgrounds, i.e. DBA/2J (D2) and C57BL/6J (B6), strains that are respectively susceptible and resistant to chronic kidney disease. RESULTS: Biochemical and histological analysis revealed that homozygous Tenc1(ICGN) mice develop nephrotic syndrome on the D2 background (D2GN) but not on the B6 background (B6GN). Initially, abnormal assembly and maturation of glomerular basement membrane (GBM) were observed, and subsequently effacement of podocyte foot processes was noted in the kidneys of D2GN but not B6GN mice. These defects are likely to be involved in the integrin signaling pathway. CONCLUSION: This study suggests that Tenc1 contributes to the maintenance of GBM structures and that the genetic background influences the severity of nephrotic syndrome.

Gene expression analysis detected a low expression level of C1s gene in ICR-derived glomerulonephritis (ICGN) mice.

BACKGROUND: ICR-derived glomerulonephritis (ICGN) strain is a novel inbred strain of mice with a hereditary nephrotic syndrome. Deletion mutation of tensin 2 (Tns2), a focal adhesion molecule, has been suggested to be responsible for nephrotic syndrome in ICGN mice; however, the existence of other associative factors has been suggested. METHODS AND RESULTS: To identify additional associative factors and to better understand the onset mechanism of nephrotic syndrome in ICGN mice, we conducted a comprehensive gene expression analysis using DNA microarray. Immune-related pathways were markedly altered in ICGN mice kidney as compared with ICR mice. Furthermore, the gene expression level of complement component 1, s subcomponent (C1s), whose human homologue has been reported to associate with lupus nephritis, was markedly low in ICGN mouse kidney. Real-time quantitative reverse transcription-polymerase chain reaction confirmed a low expression level of C1s in ICGN mouse liver where the C1s protein is mainly synthesized. A high serum level of anti-dsDNA antibody and deposits of immune complexes were also detected in ICGN mice by enzyme-linked immunosorbent assay and immunohistochemical analyses, respectively. CONCLUSION: Our results suggest that the immune system, especially the complement system, is associated with nephrotic syndrome in ICGN mice. We identified a low expression level of C1s gene as an additional associative factor for nephrotic syndrome in ICGN mice. Further studies are needed to elucidate the role of the complement system in the onset of nephrotic syndrome in ICGN mice.

Diabetes-accelerated memory dysfunction via cerebrovascular inflammation and Abeta deposition in an Alzheimer mouse model with diabetes.

Recent epidemiological studies suggest that diabetes mellitus is a strong risk factor for Alzheimer disease. However, the underlying mechanisms remain largely unknown. In this study, to investigate the pathophysiological interaction between these diseases, we generated animal models that reflect the pathologic conditions of both diseases. We crossed Alzheimer transgenic mice (APP23) with two types of diabetic mice (ob/ob and NSY mice), and analyzed their metabolic and brain pathology. The onset of diabetes exacerbated Alzheimer-like cognitive dysfunction without an increase in brain amyloid-beta burden in double-mutant (APP(+)-ob/ob) mice. Notably, APP(+)-ob/ob mice showed cerebrovascular inflammation and severe amyloid angiopathy. Conversely, the cross-bred mice showed an accelerated diabetic phenotype compared with ob/ob mice, suggesting that Alzheimer amyloid pathology could aggravate diabetes. Similarly, APP(+)-NSY fusion mice showed more severe glucose intolerance compared with diabetic NSY mice. Furthermore, high-fat diet feeding induced severe memory deficits in APP(+)-NSY mice without an increase in brain amyloid-beta load. Here, we created Alzheimer mouse models with early onset of cognitive dysfunction. Cerebrovascular changes and alteration in brain insulin signaling might play a pivotal role in this relationship. These findings could provide insights into this intensely debated association.

Oral glucose loading modulates plasma ß-amyloid level in alzheimer's disease patients: potential diagnostic method for Alzheimer's disease.

BACKGROUND: Although plasma ß-amyloid (Aß) has been suggested to be a noninvasive diagnostic biomarker for Alzheimer's disease (AD), its significance and validity have been inconclusive. Thus, it is quite important to establish a novel diagnostic method related to plasma Aß. METHODS: As our previous animal studies demonstrated a relation of glucose with plasma Aß, we examined the effect of glucose loading on plasma Aß levels in AD patients. After fasting, an oral glucose load was administered to AD patients and non-AD dementia patients, and subsequently, blood glucose, plasma insulin, and plasma Aß levels were measured. RESULTS: The plasma levels of baseline blood glucose, plasma insulin, and plasma Aß were not different between the two groups. However, immediately after glucose loading, a significant increase in plasma Aß40 and Aß42 levels was observed in AD patients, whereas a mild decrease in plasma Aß40 and Aß42 levels was detected in non-AD dementia patients. CONCLUSION: The present study clearly demonstrated a different response in plasma Aß40 and Aß42 levels after glucose loading between AD and non-AD dementia patients, which is consistent with our previous animal studies. These findings suggest a novel diagnostic tool for AD using the elevation of plasma Aß level after glucose loading, although further studies are necessary.

Activating transcription factor 3 constitutes a negative feedback mechanism that attenuates saturated Fatty acid/toll-like receptor 4 signaling and macrophage activation in obese adipose tissue.

Obese adipose tissue is markedly infiltrated by macrophages, suggesting that they may participate in the inflammatory pathways that are activated in obese adipose tissue. Evidence has suggested that saturated fatty acids released via adipocyte lipolysis serve as a naturally occurring ligand that stimulates Toll-like receptor (TLR)4 signaling, thereby inducing the inflammatory responses in macrophages in obese adipose tissue. Through a combination of cDNA microarray analyses of saturated fatty acid-stimulated macrophages in vitro and obese adipose tissue in vivo, here we identified activating transcription factor (ATF)3, a member of the ATF/cAMP response element-binding protein family of basic leucine zipper-type transcription factors, as a target gene of saturated fatty acids/TLR4 signaling in macrophages in obese adipose tissue. Importantly, ATF3, when induced by saturated fatty acids, can transcriptionally repress tumor necrosis factor-alpha production in macrophages in vitro. Chromatin immunoprecipitation assay revealed that ATF3 is recruited to the region containing the activator protein-1 site of the endogenous tumor necrosis factor-alpha promoter. Furthermore, transgenic overexpression of ATF3 specifically in macrophages results in the marked attenuation of proinflammatory M1 macrophage activation in the adipose tissue from genetically obese KKA(y) mice fed high-fat diet. This study provides evidence that ATF3, which is induced in obese adipose tissue, acts as a transcriptional repressor of saturated fatty acids/TLR4 signaling, thereby revealing the negative feedback mechanism that attenuates obesity-induced macrophage activation. Our data also suggest that activation of ATF3 in macrophages offers a novel therapeutic strategy to prevent or treat obesity-induced adipose tissue inflammation.

Adult onset cardiac dilatation in a transgenic mouse line with Galß1,3GalNAc α2,3-sialyltransferase II (ST3Gal-II) transgenes: a new model for dilated cardiomyopathy.

Sugar chain abnormalities in glycolipids and glycoproteins are associated with various diseases. Here, we report an adult onset cardiac dilatation in a transgenic mouse line with Galß1,3GalNAc α2,3-sialyltransferase II (ST3Gal-II) transgenes. The transgenic hearts at the end-stage, at around 7 months old, were enlarged, with enlarged cavities and thin, low-tensile walls, typical of dilated cardiomyopathy. Although no apparent change was found in heart gangliosides, glycosylation of heart proteins was altered. Interestingly, sugar moieties not directly related to the ST3Gal-II catalytic reaction were also changed. Significant increases in calreticulin and calnexin were observed in hearts of the transgenic mice. These results suggest that expression of ST3Gal-II transgenes induces abnormal protein glycosylation, which disorganizes the endoplasmic/sarcoplasmic reticulum quality control system and elevates the calreticulin/calnexin level, resulting in suppression of cardiac function. The transgenic mice showed 100% incidence of adult onset cardiac dilatation, suggesting great potential as a new model for dilated cardiomyopathy.

Urinary protein analysis in mice lacking major urinary proteins.

Mouse urine contains major urinary proteins (MUPs) that are not found in human urine. Therefore, even healthy mice exhibit proteinuria, unlike healthy humans, making it challenging to use mice as models for human diseases. It was also unknown whether dipsticks for urinalysis could measure protein concentrations precisely in urine containing MUPs. To resolve these problems, we produced MUP-knockout (Mup-KO) mice by removing the Mup gene cluster using Cas9 proteins and two guide RNAs and characterized the urinary proteins in these mice. We measured the urinary protein concentrations in Mup-KO and wild-type mice using a protein quantitation kit and dipsticks. We also examined the urinary protein composition using SDS-PAGE and two-dimensional electrophoresis (2DE). The urinary protein concentration was significantly lower (P<0.001) in Mup-KO mice (17.9 ± 1.8 mg/dl, mean ± SD, n=3) than in wild-type mice (73.7 ± 8.2 mg/dl, n=3). This difference was not reflected in the dipstick values, perhaps due to the low sensitivity to MUPs. This suggests that dipsticks have limited ability to measure changes in MUPs with precision. SDS-PAGE and 2DE confirmed that Mup-KO mice, like humans, had no MUPs in their urine, whereas wild-type mice had abundant MUPs in their urine. The absence of the masking effect of MUPs in 2DE would enable clear comparisons of urinary proteins, especially low-molecular-weight proteins. Thus, Mup-KO mice may provide a useful model for human urinalysis.

Analysis of the transgene insertion pattern in a transgenic mouse strain using long-read sequencing.

Transgene insertion patterns are critical for the analysis of transgenic animals because the influence of transgenes may change depending on the insertion pattern (such as copy numbers and orientations of concatenations) and the insertion position in the genome. We previously reported a genomic walking strategy to locate transgenes in the genomes of transgenic mice (Exp. Anim. 53: 103-111, 2004) and to analyze transgene insertion patterns (Exp. Anim. 55: 65-69, 2006). With such strategies, however, we could not determine the copy number of transgenes or global genome modification induced by transgene insertion due to read-length limitation. In this study, we used a long-read sequencer (MinION, Oxford Nanopore Technologies) to overcome this limitation. We obtained 922,210 reads using MinION with genomic DNA from a transgenic mouse strain (4C30, Proc. Jpn. Acad. Ser. B. Phys. Biol. Sci. 87: 550-562, 2011). Among the reads, we found one 21,457-bp read containing the transgene using a local BLAST search. Nucleotide dot plot analysis revealed that the transgene was inserted in the genome as a tandem concatemer with an almost entire construct (15-3,508 of 3,508 bp) and a partial fragment (4-660, 657 bp). Ensembl's BLAST search against the C57BL/6N genome revealed a 9,388-bp deletion at the insertion position in the intron of the Sgcd gene, confirming that mutations such as a large genomic deletion could occur at the time of transgene insertion. Thus, long-read sequencers are useful tools for the analysis of transgene insertion patterns.

Elevation of plasma beta-amyloid level by glucose loading in Alzheimer mouse models.

With the emergence of a promising approach to treat Alzheimer disease (AD) targeting the beta-amyloid (Abeta) pathway, it is necessary to establish new diagnostic biomarkers that enable the antemortem diagnosis of AD. Although plasma Abeta has been suggested as a non-invasive biomarker, its significance has been inconclusive. Thus, it is important to improve the diagnostic potential of plasma Abeta. One of the potential approaches is to modify plasma Abeta level using various modulators. In this study, we evaluated the influence of glucometabolic status on plasma Abeta level in two lines of AD transgenic mouse. The present study demonstrated that plasma Abeta level rapidly increased after glucose loading. More importantly, the magnitude of the increase in plasma Abeta was significantly larger in AD transgenic mice than in wild-type littermates. These findings might provide a novel diagnostic tool for AD using the elevation of plasma Abeta level after glucose loading.

Type 2 diabetes mellitus in a non-obese mouse model induced by Meg1/Grb10 overexpression.

We assessed the possibility of C57BL/6-Tg (Meg1/Grb10)isn(Meg1 Tg) mice as a non-obese type 2 diabetes (2DM) animal model. Meg1 Tg mice were born normal, but their weight did not increase as much as normal after weaning and showed about 85% of normal size at 20 weeks of age. Body mass index of Meg1 Tg mice was also smaller than that of control mice. The glucose tolerance test and insulin tolerance test showed that Meg1 Tg mice had reduced ability to normalize the blood glucose level. Blood urea nitrogen (BUN) in Meg1 Tg mice (19.6 +/- 1.2 mg/dl) was significantly lower than in controls (22.0 +/- 0.8 mg/dl), while plasma triglyceride, insulin, adiponectin, and resistin levels were significantly higher (202.0 +/- 23.4 mg/dl vs 146.3 +/- 23.4 mg/dl, 152.4 +/- 16.3 pg/ml vs 88.1 +/- 16.9 pg/ml, 74.4 +/- 10.9 microg/ml vs 48.3 +/- 7.0 microg/ml, and 4.0 +/- 0.2 ng/ml vs 3.6 +/- 0.2 ng/ml, respectively). Body, visceral fat weight and liver weights were significantly lower (19.6 +/- 0.4 g vs 24.3 +/- 0.3 g, 376.7 +/- 29.6 mg to 507.5 +/- 23.0 mg, and 906.0 +/- 41.8 mg to 1,001.0 +/- 15.1 mg, respectively). Thus, hyperinsulinemia observed in Meg1 Tg mice indicates that their insulin signaling pathway is somehow inhibited. With high fat diet, the diabetes onset rate of Meg1 Tg mice increased up to 60%. These results suggest that Meg1 Tg mice resemble human 2DM.

Incorrect strain information for mouse cell lines: sequential influence of misidentification on sublines.

Misidentification or cross-contamination of cell lines can cause serious issues. Human cell lines have been authenticated by short tandem repeat profiling; however, mouse cell lines have not been adequately assessed. In this study, mouse cell lines registered with the JCRB cell bank were examined by simple sequence length polymorphism (SSLP) analysis to identify their strains. Based on comparisons with 7 major inbred strains, our results revealed their strains in 80 of 90 cell lines. However, 12 of the 80 cell lines (15%) were found to differ from registered information. Of them, 4 cell lines originated from the same mouse, which had been generated through mating between two different inbred strains. The genotype of the mouse sample had not been examined after the backcross, leading to strain misidentification in those cell lines. Although 8 other cell lines had been established as sublines of a BALB/c cell line, their SSLP profiles are similar to a Swiss cell line. This affects differences in genotypes between inbred and outbred strains. Because the use of inbred samples and interbreeding between strains are not involved in human materials, our results suggest that the cause and influence of misidentification in mouse cell lines are different from those in human.

Epstein-Barr virus infection and gene promoter hypermethylation in rheumatoid arthritis patients with methotrexate-associated B cell lymphoproliferative disorders.

We analyzed CpG-island hypermethylation status in 12 genes of paraffin-embedded tissues from 38 rheumatoid arthritis (RA) patients with methotrexate (MTX)-associated large B cell lymphoproliferative disorder (BLPD), 11 RA patients with non-MTX-associated BLPD (non-MTX-BLPD), 22 controls with diffuse large B cell lymphoma (DLBCL), and 10 controls with Epstein-Barr virus (EBV)+ DLBCL. Among them, tumor cells from EBV+ MTX-BLPD patients and control EBV+ DLBCL patients had significantly lower median incidence of CpG island methylator phenotype (CIMP) than those from non-MTX-BLPD and control DLBCL groups (2.3 and 1.7 vs. 4.3 and 4.4; P < 0.01 for each). In the MTX-BLPD group, EBV+ patients showed lower median CIMP than EBV- patients (2.3 vs. 3.2); they also had significantly lower hypermethylation incidence in four apoptosis-related genes, especially death-associated protein kinase (14 vs. 55 %), higher incidence of massive tumor necrosis (86 vs. 27 %), and lower BCL2 protein expression (19 vs. 86 %) than did the control DLBCL group (P < 0.01 for all). In all clinical stages, EBV+ MTX-BLPD patients had better prognoses than the EBV- MTX-BLPD (P = 0.011), non-MTX-BLPD (P = 0.002), and control DLBCL groups (P = 0.015). MTX-BLPD patients without hypermethylated RAS-associated domain family-1A (RASSF1A) or O 6 -methyl guanine-DNA methyltransferase (MGMT) had significantly better prognosis than those with hypermethylation of those genes (P = 0.033). We conclude that in RA patients with MTX-BLPD, EBV infection is associated with a lower incidence of CIMP, apoptosis-related gene hypermethylation, and BCL2 expression, which can induce tumor regression by MTX withdrawal and lead to better prognoses.

Transgene insertion pattern analysis using genomic walking in a transgenic mouse line.

A transgene mapping technique (Noguchi et al., Exp. Anim. 53:103-111, 2004) is described that can be used to analyze transgene integration patterns in transgenic mice. The technique was used to reveal that a transgenic mouse line (GM1-sy#116) harbored inverted and direct tandem repeats of both intact and partial pCAGGS-based transgenes in the G2 region of chromosome 1. This complicated concatenation of transgenes may have been caused by simple end-joining of DNA constructs fragmented by exposure to UV transillumination during gel-purification, and by nuclease digestion inside zygote pronuclei. The results suggest that care should be taken to avoid unwanted fragmentation during the preparation of vector constructs.