The Impact of c-Fos/Activator Protein-1 Inhibition on Allogeneic Pancreatic Islet Transplantation

Unpreventable allograft rejection is one of the main problems in pancreatic islet transplantation (PIT). Therefore, it is imperative to develop a more effective immunosuppressive strategy. The blockade of transcription factors has been a central part of T cell-depleting immunosuppressive therapies, as typified by the use of calcineurin inhibitors. The inhibition of activator protein-1 (AP-1) offers a novel strategy for immunosuppression in PIT, although to date, no reports on the effects of AP-1 inhibition are available. In this study, we investigated the immunosuppressive effects of T-5224, a c-Fos/AP-1-selective inhibitor, on murine T cells activated by αCD3+αCD28 mAbs. T-5224 inhibited proliferation, CD25 up-regulation, and the production of IL-2 and interferon-γ. In addition, T-5224 blocked the nuclear translocation of c-Fos/AP-1 in activated murine T cells. In BALB/c (H-2(d) )-to-C57BL/6J (H-2(b) ) mouse PIT, the 2-week administration of T-5224 prolonged survival of 600 islet allografts in a dose-dependent manner. When combined with a 2-week low-dose tacrolimus, the T-5224 treatment markedly prolonged allograft survival to over 300 days, while the efficacy was indeterminate when transplanted islet allograft mass was reduced to 300. We conclude that the c-Fos/AP-1 inhibition by T-5224 is a potentially attractive strategy for allogeneic PIT.

Additional Surgery After Non-curative Resection of ESD for Early Gastric Cancer

AIM

The appropriate additional surgery after non-curative resection of Endoscopic Mucosal Resection (ESD) for early gastric cancer is herein discussed.

PATIENTS AND METHODS

Data on 54 patients after non-curative resection of ESD were evaluated. These patients were broadly classified according to the risk of lymph node metastasis with lesions into group A (without risk) (n=26) and group B (with risk) (n=28). Their treatment results were evaluated.

RESULTS

The incidence of residual lesion was 7.7% in group A and 14.3% in group B. Risk factors were piecemeal resection, involvement of the horizontal margin (HM1) or unclear involvement of the horizontal margin (HMX) and with ulceration. Lymph node metastasis was detected in one patient with lymphatic invasion, total diameter of 3 cm or more and submucosal invasion over 0.5 mm (SM2). The 5-year survival rate was 93% and none of the patients died of gastric cancer.

CONCLUSION

Follow-up observation was reasonable in group A. Patients who are judged as having undergone piecemeal resection, HM1 or HMX and with ulceration, should be treated by additional surgery and patients judged with SM2 or total diameter of 3 cm or more or lymphatic invasion should be treated by additional surgery with lymphadectomy in group B.

Preoperative bone mineral density in gastric cancer patients

BACKGROUND/AIMS

It has been reported that there is a high rate of bone mineral density (BMD) loss after gastrectomy for gastric cancer. To clarify the course of postoperative BMD loss, it is necessary to precisely determine the preoperative BMD of gastric cancer patients.

METHODOLOGY

From October 2005 through September 2008, preoperative BMD was measured in 91 patients (59 males and 32 females, mean age of the patients was 67.3 years) who underwent gastrectomy for gastric cancer. Then, the percentage of the subject's BMD divided by the BMD of young adult mean (YAM) (% of YAM) was obtained for each subject and the incidence of osteoporosis as well as the relationship between % of YAM and the patient's clinico-pathological factors or biochemical parameters was examined.

RESULTS

The incidence of osteoporosis was 15.4%. There is a correlation between BMD in preoperative gastric cancer patients and serum albumin levels, and BMD decreases further in the elderly and individuals with a BMI lower than 18.5.

CONCLUSIONS

From the viewpoint of osteoporosis prevention, this suggests the importance of nutritional management for elderly gastric cancer patients with associated nutritional disorder.

STUDIES OF LEPTOSPIRA HEBDOMADIS

From the results of etiological study of the disease known as akiyami which prevails in the Shida district of Shizuoka province, we conclude that: 1. Akiyami is an infectious disease caused by a leptospira. 2. The leptospira causing akiyami is very difficult to differentiate morphologically from Leptospira icterohœmorrhagiœ and Leptospira hebdomadis. 3. The strains of leptospira isolated from cases of akiyami are of two types. One type, isolated from three of the sixteen cases, is highly virulent for guinea pigs and is serologically distinct from Leptospira icterohœmorrhagiœ and Leptospira hebdomadis; we have called this the A type. The type obtained from the other cases is less virulent for guinea pigs and is serologically identical with Leptospira hebdomadis; we have called this the B type. 4. The field mouse (Microtus montebelli), which harbors Leptospira hebdomadis, has also been found to harbor the A type of akiyami.

Opening the flood gates: interferon-alpha treatment for Sjögren's syndrome

Interferon (IFN)-alpha is the main IFN produced in response to viral infection. Low levels of IFNalpha can be detected in nasal secretions after exposure to viruses in vivo. Radioimmunoassay has shown that endogenous IFNalpha is low in children, reaches a peak in young adults, and gradually declines with aging. Importantly, this endogenous IFNalpha is significantly decreased in patients with Sjögren's syndrome (SS). IFNalpha has been tested as a therapeutic agent in patients with SS. Intramuscular human leucocyte IFNalpha increases saliva production significantly in patients with SS. Improvements have been noted in lacrimal function and in dryness symptoms. Since IFNalpha infrequently induces autoimmune phenomena and high dose IFNalpha treatment sometimes has a serious adverse event profile, treatment focus has shifted to use of low dose orally-administered IFNalpha. In a single-masked controlled trial, 60 patients with SS randomly received natural human IFNalpha 150IU 3 times a day in an oral lozenge formulation or sucralfate as control for 6 months. At study end, 15 (50%) of the 30 IFNalpha-treated patients had saliva production increases at least 100% above baseline. IFNalpha treatment was well tolerated and no patients withdrew. Labial minor salivary gland biopsies indicated significant decreases in lymphocytic infiltration accompanied by a significant increase in intact salivary gland tissue after 6 months of treatment. In another 12-week double-masked, randomised, placebo-controlled trial, stimulated saliva production in patients with SS receiving IFNalpha lozenges 150IU 3 times daily was significantly increased. This dosage was also suggestive of benefit for 5 of 7 subjective measures of oral and ocular comfort. The tolerability profile of these low dose oral IFNalpha lozenges is excellent; no serious adverse events have been recorded. Adverse effects were generally mild and there were no clinically significant changes in laboratory or clinical safety measures. Low oral doses of natural human IFNalpha thus appear to improve secretory function and relieve dryness in patients with SS without causing significant adverse events. Endogenous or orally administered IFNalpha may activate oropharyngeal lymphoid and epithelial cells and induce production of potent soluble factors which could mediate immunological reactivity. It has been suggested that IFNalpha/beta potentiates clonal expansion and survival of CD8 T cells. Stimulating effects have also been demonstrated on natural killer cell activity, which has been shown to be depressed in patients with SS. It is likely that some combination of these immunological effects results in anti-inflammatory activity and ameliorates signs and symptoms of SS.

Anchorage on fibronectin via VLA-5 (alpha5beta1 integrin) protects rheumatoid synovial cells from Fas-induced apoptosis

BACKGROUND

Rheumatoid synovial cells are resistant to apoptosis induction in vivo, whereas, fibroblast-like synovial cells in rheumatoid arthritis (RA-FLS) are vulnerable to Fas-induced apoptosis in vitro.

OBJECTIVE

To clarify this discrepancy by studying the contribution of the interaction between cellular integrin and matrix fibronectin (Fn), which is significantly increased in the rheumatoid joints, to the induction of apoptosis in RA-FLS.

METHODS

Integrin and Fas mRNAs were measured by reverse transcription-polymerase chain reaction in RA-FLS. Integrins expressed in rheumatoid synovial tissues were analysed by immunohistochemistry. RA-FLS plated either on Fn or on control poly-L-lysine were incubated with agonistic anti-Fas monoclonal antibodies (mAbs). Apoptosis induction was evaluated using terminal deoxynucleotidyl transferase mediated UTP nick end labelling (TUNEL) and immunoblotting for caspase-3 and poly (ADP-ribose) polymerase in the presence or absence of anti-VLA-5 mAb.

RESULTS

VLA-5 (alpha5beta1 integrin), a major integrin expressed on RA-FLS, was required for the adhesion of RA-FLS on Fn. RA-FLS plated on Fn were more resistant to Fas-induced apoptosis than those plated on control poly-L-lysine. This protection by Fn was reversed by anti-VLA-5 mAb.

CONCLUSION

Anchorage of RA-FLS on matrix Fn via VLA-5 protects RA-FLS from Fas-induced apoptosis, and Fn abundantly present in rheumatoid synovium appears to afford RA-FLS resistance against apoptosis induction in vivo.

Death receptor 3 (DR3) gene duplication in a chromosome region 1p36.3: gene duplication is more prevalent in rheumatoid arthritis

The death receptor 3 (DR3) gene is a member of the apoptosis-inducing Fas gene family. In the current study, fluorescence in situ hybridization (FISH) and Fiber-FISH revealed the existence of a second DR3 gene approximately 200 kb upstream of the original DR3 gene. The existence of the duplicated DR3 gene was confirmed by sequencing the corresponding human artificial chromosome clones as well as with quantitative PCR that measured the ratio of the DR3 gene mutation (Rm), intrinsic to rheumatoid arthritis (RA) patients, by simultaneous amplification of the normal and mutated DR3 sequences. The DR3 gene duplication measured by FISH was found to be more frequent in patients with RA as compared to healthy individuals. We therefore surmise that the human DR3 gene can be duplicated and that this gene duplication is more prevalent in patients with RA.

Alternatively spliced EDA-containing fibronectin in synovial fluid as a predictor of rheumatoid joint destruction

OBJECTIVES

Fibronectin containing the EDA region (EDA(+)Fn), a molecule important for rheumatoid joint destruction, was measured in relation to the progression of joint destruction in rheumatoid arthritis (RA).

METHODS

Total Fn and EDA(+)Fn were measured by ELISA, and the concentrations of Fn in plasma and synovial fluid were compared prospectively for 2 yr with the progression of joint destruction in 41 knee joints of 37 patients with RA. The extent of joint destruction was assessed by the Larsen score and joint space narrowing in X-ray films taken before and 2 yr after measurement of EDA(+)Fn.

RESULTS

The concentration of synovial fluid EDA(+)Fn showed a positive correlation with the progression of joint destruction in RA (r=0.78). While total Fn in synovial fluid also showed a correlation with joint destruction (r=0.54), total Fn and EDA(+)Fn in plasma showed no correlation with joint destruction. The concentration of synovial fluid EDA(+)Fn was significantly higher in patients who underwent joint replacement after the measurement of EDA(+)Fn than in those who did not receive surgery (P<0.029).

CONCLUSION

Synovial fluid EDA(+)Fn can be a predictor of subsequent joint destruction in RA.

Intra-articular injection of hyaluronate (SI-6601D) improves joint pain and synovial fluid prostaglandin E2 levels in rheumatoid arthritis: a multicenter clinical trial

OBJECTIVE

The relationship between clinicalfeatures and biochemical parameters of synovialfluid after serial intra-articular injections of sodium hyaluronate (SI-6601D) was investigated.

METHODS

SI-6601D (sodium hyaluronate with an average molecular weight of 8.4 x 10(5); 25mg/2.5ml/syringe) was injected intra-articularly into the knees of 25 patients with rheumatoid arthritis (RA) every week for 5 consecutive weeks. Clinical and biochemical parameters were monitored before and after injection. Clinicalfindings included pain, as a summation of 3 categories (pain at rest, pain in motion and pain in passive motion, each assessed on a 4-step rating scale), and inflammation, also as a summation of 3 categories (swelling, patellar ballotement and local warmth, each assessed on a 4-step rating scale). Pain on walking of patient was qualitatively assessed by visual analogue scale (VAS). The aspirated volume of synovialfluid (SFV) was recorded and levels of prostaglandin (PG) E2, transforming growth factor beta-1, tumor necrosis factor alpha, interleukin I receptor antagonist, chondroitin 4-sulfate (C4S) and chondroitin 6-sulfate were measured.

RESULTS

Significant improvement in pain symptoms (p < 0.0001), inflammation (p < 0.0001), VAS pain (p < 0.001) and SFV (p < 0.05) were observed after the 5 injections. Levels of PGE2 (p < 0.05) and C4S (p < 0.05) in the synovialfluid were significantly decreased.

DISCUSSION

SI-6601D improved local clinical symptoms in RA patients by suppressing PGE2 and, therefore, may be a useful treatment for local inflammation in RA.

Prostacyclin inhibits the production of MMP-9 induced by phorbol ester through protein kinase A activation, but does not affect the production of MMP-2 in Human cultured mesangial cells

BACKGROUND/AIMS

The imbalance between degradation and synthesis of the glomerular extracellular matrix (ECM) causes glomerular sclerosis in various types of glomerulonephritis. We investigated the effect of prostacyclin, which is an inflammatory mediator, on the production of matrix metalloproteinase (MMP)-9 and MMP-2 in human cultured mesangial cells. The synthesis of Jun proteins and Ets-1 proteins, which are related with MMP-9 gene, was also studied.

METHODS

The production of MMP-9 and MMP-2 was investigated by gelatin zymography. Western blotting was undertaken to analyze the protein synthesis of Jun and Ets-1.

RESULTS

Prostacyclin inhibited the production of MMP-9 induced by phorbol ester. The inhibitory effect by prostacyclin was reversed in part by the pretreatment with an inhibitor of protein kinase A, such as H-89. Forskolin also inhibited the production of MMP-9. The production of MMP-2 was constitutionally seen and was not influenced by prostacyclin and forskolin. The synthesis of Jun protein augmented by phorbol ester was suppressed by prostacyclin. Ets-1 protein was constitutionally synthesized and was not affected by phorbol ester and prostacyclin.

CONCLUSION

Prostacyclin plays an important role in inflammatory glomerular disorders by regulating the metabolism of ECM. The production of MMP-9 and MMP-2 may be under the different control pathways.

An approach to identify new genes in autoimmune diseases: lessons from rheumatoid arthritis

We have searched the human genome for genes that predispose to rheumatoid arthritis using fluorescence-based microsatellite marker analysis and affected sib-pair linkage studies. A panel of 41 Japanese families, each with at least two affected siblings, was typed for genome-wide 358 polymorphic microsatellite marker loci. Three principal chromosome regions of linkage, D1S253/214, D8S556 and DX1232, have been assigned, which we call RA1, RA2 and RA3 for rheumatoid arthritis disease loci. We are now assigning the death receptor 3 as a candidate gene for RA1, and the truncated form of Dbl proto-oncogene, which does not contain the 23rd and 24th exons, as disease gene for RA3. Microsatellite marker analyses seem to be promising and new genes are now being identified by reference to sequence tag sites.

Dual metabolic pathway of 25-hydroxyvitamin D3 catalyzed by human CYP24

Human 25-hydroxyvitamin D3 (25(OH)D3) 24-hydroxylase (CYP24) cDNA was expressed in Escherichia coli, and its enzymatic and spectral properties were revealed. The reconstituted system containing the membrane fraction prepared from recombinant E. coli cells, adrenodoxin and adrenodoxin reductase was examined for the metabolism of 25(OH)D3, 1alpha,25(OH)2D3 and their related compounds. Human CYP24 demonstrated a remarkable metabolism consisting of both C-23 and C-24 hydroxylation pathways towards both 25(OH)D3 and 1alpha,25(OH)2D3, whereas rat CYP24 showed almost no C-23 hydroxylation pathway [Sakaki, T. Sawada, N. Nonaka, Y. Ohyama, Y. & Inouye, K. (1999) Eur. J. Biochem. 262, 43-48]. HPLC analysis and mass spectrometric analysis revealed that human CYP24 catalyzed all the steps of the C-23 hydroxylation pathway from 25(OH)D3 via 23S, 25(OH)2D3, 23S,25,26(OH)3D3 and 25(OH)D3-26,23-lactol to 25(OH)D3-26, 23-lactone in addition to the C-24 hydroxylation pathway from 25(OH)D3 via 24R,25(OH)2D3, 24-oxo-25(OH)D3, 24-oxo-23S,25(OH)2D3 to 24,25,26,27-tetranor-23(OH)D3. On 1alpha,25(OH)2D3 metabolism, similar results were observed. These results strongly suggest that the single enzyme human CYP24 is greatly responsible for the metabolism of both 25(OH)D3 and 1alpha,25(OH)2D3. We also succeeded in the coexpression of CYP24, adrenodoxin and NADPH-adrenodoxin reductase in E. coli. Addition of 25(OH)D3 to the recombinant E. coli cell culture yielded most of the metabolites in both the C-23 and C-24 hydroxylation pathways. Thus, the E. coli expression system for human CYP24 appears quite useful in predicting the metabolism of vitamin D analogs used as drugs.

Spontaneous and cytokine regulated c-fos gene expression in rheumatoid synovial cells: resistance to cytokine stimulation when the c-fos gene is overexpressed

OBJECTIVE

To study the effect of cytokines on the transactivation of the c-fos gene in relation to the contribution of overexpression of c-fos/AP-1 in rheumatoid joint destruction.

METHODS

The promoter region (-447 to +109) of the human c-fos gene was integrated upstream of the chloramphenicol acetyltransferase (CAT) reporter gene, and the effect of cytokines on the expression of the c-fos gene was studied in the rheumatoid synovial cells of early (3-4) or late (14-18) passages, in the presence or absence of cytokines, by the transient transfection assay.

RESULTS

Expression of c-fos gene was enhanced by tumour necrosis factor alpha (TNF alpha) and interleukin 6 (IL6) in the synovial cells of early passage, whereas it was not enhanced in the synovial cells of late passage. The c-fos gene expression was also enhanced by 13-O-tetradecanoyl phorbol-13-acetate (TPA) in early passage but was somewhat suppressed in the late passage. It was found that the c-fos gene and c-Fos protein were both increased in the synovial cells of late passage. Similarly, c-fos gene expression was also not increased by TPA or cytokine stimulation in the stable c-fos transformants (fos-pH8) or H-ras transformed NIH3T3 cells (NIH H-ras cells) that constitutively expressed c-fos genes.

CONCLUSIONS

Although TNF alpha and IL6 augmented c-fos gene expression of rheumatoid synovial cells, transactivation of c-fos gene became resistant against cytokine stimulation under prolonged expression of c-fos gene, which may impart a tumour-like characteristic to rheumatoid synovial cells.

Platelet-activating factor acetylhydrolase gene mutation in Japanese children with Escherichia coli O157-associated hemolytic uremic syndrome

Platelet-activating factor (PAF) may be involved in the pathogenesis of Escherichia coli O157-associated hemolytic uremic syndrome (HUS). PAF is degraded to inactive products by PAF acetylhydrolase. In this study, we investigated whether a PAF acetylhydrolase gene mutation (G-->T transversion at position 994) is involved in HUS in Japanese children. A point mutation in the PAF acetylhydrolase gene (G994T) was identified using polymerase chain reaction in 50 Japanese children with E coli O157-associated HUS and 100 healthy Japanese. We then determined the relationship between the PAF acetylhydrolase G994T gene mutation and clinical features of HUS. There was no difference in genotype and allele frequencies between patients with HUS and healthy controls. The mean duration of oligoanuria was significantly longer in patients with the GT genotype than in those with the GG genotype (P = 0.012). Although 11 of 15 patients (73%) heterozygous for the mutant allele (GT) required dialysis, only 13 of the 35 wild-type homozygotes (GG; 37%) required dialysis (P = 0. 030). Mean plasma PAF acetylhydrolase activity was significantly less in patients with the GT genotype than in those with the GG genotype (P < 0.0001). In conclusion, we have shown an association between the G994T PAF acetylhydrolase gene mutation and the severity of renal damage in E coli O157-associated HUS. Our study suggests that analysis of the PAF acetylhydrolase gene mutation in Japanese children with E coli O157-associated HUS may allow the prediction of the severity of HUS.

Participation of macrophages in glomerular sclerosis through the expression and activation of matrix metalloproteinases

In order to investigate the role of macrophages in glomeruli in the progression of glomerular sclerosis, methyl-cellulose (MC) was administered intraperitoneally to Wistar rats, in addition to intravenous injection of anti-thy1-1 antibody. In this group of rats (Thy-1 + MC group), many macrophages infiltrated in the lytic mesangium accompanied by rupture of capillary loops at an early stage and stayed with abundant deposition of mesangial matrices until day 35, whereas the proliferative lesions following mesangiolysis almost vanished in the rats treated with anti-thy1-1 antibody alone (Thy-1 group). In immunostaining, matrix metalloproteinase (MMP)-9 was expressed along regenerating capillaries of the Thy-1 group and in extracapillary lesions of the Thy-1 + MC group after day 7. In gelatin zymography, the gelatinolytic band for MMP-9 was expressed much more strongly in the Thy-1 + MC group than in the Thy-1 group at day 3, but it was expressed a little more strongly in the Thy-1 group than in the Thy-1 + MC group at day 7. The bands for an active form of MMP-2 were more strongly expressed in the Thy-1 + MC group than in the Thy-1 group throughout the experimental period. These results suggest that persistent accumulation of macrophages in mesangium induces glomerular sclerosis through expression and activation of MMP.

Increased c-Fos/activator protein-1 confers resistance against anergy induction on antigen-specific T cell

We have studied the contribution of c-Fos/activator protein-1 (AP-1) to antigen-specific T cell response with reference to T cell anergy by increasing c-Fos/AP-1 in vivo and in vitro. First, after injection of a high dose of staphylococcus enterotoxin B (SEB), clonal deletion of SEB-reactive V(beta)8(+) CD4 T cells occurred both in control B6 and H2-c-fos transgenic (fos) mice, whereas proliferation of T cells against SEB was profoundly depressed in B6 but not in fos mice. Second, the keyhole limpet hemocyanin-specific CD4 T(h)1 cell clone produced decreasing amounts of IL-2 in response to increasing amounts of concanavalin A (Con A) in vitro, whereas the decrease was less significant in the T(h)1 clones stably transfected with c-fos gene. Electrophoretic mobility shift assay with nuclear protein from the transformants showed that overexpression of the c-fos gene compensated the amounts of AP-1 in the nuclei of Con A-treated T(h)1 clones. Thus, increased c-Fos/AP-1 confers resistance against anergy induction on antigen-specific T cells.

Prevalence of non-ulcer dyspepsia in the Japanese population

BACKGROUND

Non-ulcer dyspepsia (NUD) is one of the most frequently encountered disorders in general practice in Western countries. The prevalence of this disorder in the Japanese, however, has not been fully investigated. This study is designed to clarify the characteristics and prevalence of dyspepsia in the Japanese.

METHODS

The subjects were 1139 people who visited our institutes for their annual medical check up for gastric cancers. After routine medical examination, all subjects were asked standardized questions in order to check for the presence of any symptoms suggesting dyspepsia.

RESULTS

The results of the study showed that dysmotility-like dyspepsia, characterized by the presence of nausea, fullness and early satiety, is the most frequently observed dyspepsia in Japanese and that this type of dyspepsia decreases with age. Ulcer-like dyspepsia, which is the major type of dyspepsia in Western countries, is the least frequently experienced dyspepsia in the Japanese.

CONCLUSIONS

This study clarified that NUD is also one of the most prevalent disorders in the Japanese, although its characteristics may be somewhat different from those in Western countries.

Natural killer (NK) T cells are significantly decreased in the peripheral blood of patients with rheumatoid arthritis (RA)

The number of NK T cells was measured in relation to the Th1/Th2 imbalance observed in RA. Peripheral blood samples of patients with RA (n = 60) and healthy controls (n = 36) were stained with anti-NK receptor 1A (anti-NKR-P1A), anti-CD56, and anti-CD3 MoAbs, and examined by three-colour flow cytometry. NK T (NKR-P1A+CD3+) cells in the peripheral blood were decreased in RA compared with the controls: 25 +/- 20/microl versus 143 +/- 53/microl (P < 0.0001). CD56+CD3+ cells were also decreased in RA: 60 +/- 46/microl versus 116 +/- 54/microl (P < 0.0001). The decrease was significant when adjusted to the number of total lymphocytes (P < 0.0001) or NK (CD56+CD3-) cells (P < 0.0001), and showed no correlation with age, sex, disease duration, disease activity, functional class, x-ray stage, drug treatment, joint score, grip strength, C-reactive protein, rheumatoid factor or erythrocyte sedimentation rate of the patients. The results show that the levels of NK T cells are depressed in the peripheral blood of patients with RA, suggesting that the measurement of NK T cells in peripheral blood may have clinical importance for a Th1-type autoimmune disease like RA.

Role of platelet-activating factor acetylhydrolase gene mutation in Japanese childhood IgA nephropathy

Platelet-activating factor (PAF) is a potent mediator of inflammatory injury in renal diseases. PAF is degraded to inactive products by PAF acetylhydrolase. Recently, a point mutation (G to T transversion) of the PAF acetylhydrolase gene was observed at position 994, and this mutation was found to contribute to the variability in plasma PAF levels, with undetectable plasma PAF acetylhydrolase activity occurring in homozygous patients (TT genotype) and reduced levels of activity in heterozygous patients (GT genotype). Therefore, we investigated the effect of the PAF acetylhydrolase gene mutation on the pathogenesis and progression of immunoglobulin A (IgA) nephropathy. Genomic DNA was obtained from 89 children with IgA nephropathy and 100 controls. We identified the PAF acetylhydrolase gene mutation (G994T) by polymerase chain reaction. There was no significant difference in genotypic frequency between patients and controls. However, urinary protein excretion at the time of biopsy was significantly greater in patients with the GT/TT genotypes than in those with the GG genotype. The percentage of glomeruli with mesangial cell proliferation was significantly greater in patients with the GT/TT genotypes than in those with the GG genotype. These results indicate the PAF acetylhydrolase gene mutation may influence the degree of proteinuria and the extent of mesangial proliferation in the early stage of childhood IgA nephropathy.

Platelet-activating factor acetylhydrolase gene mutation in Japanese nephrotic children

BACKGROUND

Platelet-activating factor (PAF) may be involved in the pathogenesis of steroid-responsive nephrotic syndrome (SRNS). PAF is degraded to inactive products by PAF acetylhydrolase. We have investigated whether PAF acetylhydrolase gene mutation is involved in SRNS in Japanese children.

METHODS

We identified a point mutation in the PAF acetylhydrolase gene (G994T) using the polymerase chain reaction in 101 Japanese children with SRNS and 100 healthy Japanese.

RESULTS

There was no difference in the genotype and allele frequencies between patients with SRNS and normal controls. The mean number of relapses during the first year after onset was significantly higher in the 26 patients who were heterozygous for the mutant allele (GT) than in 75 wild-type homozygotes (GG) (2.61 +/- 1.98 vs. 1.33 +/- 1.35; P = 0.0019).

CONCLUSIONS

We conclude that analysis of the PAF acetylhydrolase gene mutation at position 994 in Japanese children with SRNS allows the identification of patients who are more likely to have a disease relapse.

Identification of the gene loci that predispose to rheumatoid arthritis

We have searched the human genome for genes that predispose to rheumatoid arthritis (RA) using fluorescence-based microsatellite marker analysis and affected sib-pair linkage study. A panel of 41 Japanese families, each with at least two affected siblings, was typed for genome-wide 358 polymorphic microsatellite marker loci. Markers were amplified by the PCR using fluorescence-tagged primers and sized based on the difference of CA repeats on DNA. Linkage analysis was made using maximum lod score (MLS). The MLS for D1S214 and D8S556 was 3.27 and 3.33, while the MLS for the HLA-DRB1 region was <3.0. According to detailed analysis by single-point analysis using MAPMAKER/SIBS, the MLS for D1S253 and D1S214 was 3.77 and 3.58. The MLS by multipoint analysis was 6.13 for D1S253. The MLS for D8S556 by single-point analysis was 4.20. The MLS for DXS1232 was 2.35 by single-point analysis, whereas the MLS for the region 2 cM right to DXS1232 and the region between DXS1227 and DXS1200 was 3.03 and 2.93 by multi-point analysis. Three principal chromosome regions of linkage, D1S253/214, D8S556 and DXS1232, have been identified which we call RA1, RA2 and RA3 for RA disease loci.

Single-blinded controlled trial of low-dose oral IFN-alpha for the treatment of xerostomia in patients with Sjögren's syndrome

A single-blinded controlled trial was conducted to test the efficacy of low-dose oral human interferon-alpha (IFN-alpha) to improve salivary function in patients with Sjögren's syndrome. Fifty-six outpatients with primary and 4 patients with secondary Sjögren's syndrome were assigned randomly into treatment groups of either IFN-alpha or sucralfate (control). The IFN-alpha (150 IU) or sucralfate (250 mg) was given orally three times a day for 6 months. Saliva was quantitated monthly by the Saxon test. After 6 months of treatment, 15 of 30 (50%) IFN-alpha-treated patients had saliva production increases at least 100% above baseline, whereas only 1 of 30 (3.3%) sucralfate patients had a comparable increase (p < 0.001). The increase in saliva production, by treatment group, was significantly greater (p < 0.01) in the IFN-alpha treated group at every month after treatment. Serial labial salivary gland biopsies of 9 IFN-alpha responder patients showed that lymphocytic infiltration was significantly decreased (p < 0.02) and the proportion of intact salivary gland tissue was significantly increased (p = 0.004) after the IFN-alpha treatment. In this study, IFN-alpha therapy significantly improved Sjögren's syndrome salivary gland dysfunction.

Studies on the contribution of c-fos/AP-1 to arthritic joint destruction

Features characteristic to rheumatoid joint destruction, including synovial overgrowth and bone resorption, are experimentally produced by augmenting c-fos gene expression. We tested here if arthritic joint destruction was inhibited upon inactivation of the c-fos/AP-1 signal by administering short double-stranded AP-1 DNA oligonucleotides into mice with collagen-induced arthritis to compete for the binding of AP-1 in vivo at the promoter binding site. Arthritic joint destruction was inhibited in a sequence-specific and dose-dependent manner by oligonucleotides containing the AP-1 sequence. The oligonucleotides inhibited gene expression at the transcriptional level. Nucleotide sequences besides AP-1 also appeared to be important structurally for binding of AP-1 onto DNA and for the stability of oligonucleotides against nucleases. Immunohistochemical chase experiment administering biotinylated oligonucleotides into arthritic mice showed that AP-1 oligonucleotides reached the inflamed joint. Thus, activation of c-fos/AP-1 appears essentially important in arthritic joint destruction.

Adherence of synovial cells on EDA-containing fibronectin

OBJECTIVE

To investigate the role of EDA-containing fibronectin (EDA+ FN), a splice variant of FN detectable in association with cellular transformation, in the adherence of synovial cells (SC) on rheumatoid cartilage surface.

METHODS

The number of SC adherent on cartilage slices or on culture plates containing either EDA+ FN or plasma FN (pFN) was enumerated under a phase-contrast microscope. The portion of the FN molecule responsible for adherence of SC onto EDA+ FN was investigated by inhibition studies using antibodies or peptide fragments.

RESULTS

SC adhered more strongly on the surfaces containing EDA+ FN than on those containing pFN (P < 0.01). When monoclonal antibodies against the EDA or the carboxyl-terminal heparin-binding (Hep2) domains were used, adhesion of SC onto EDA+ FN was reduced to a level comparable with that onto pFN. FN fragments containing Hep2 or heparan sulfate inhibited the adhesion of SC onto EDA+ FN. Treatment of SC with heparitinase, but not heparinase, reduced the adhesion of SC onto EDA+ FN.

CONCLUSION

EDA+ FN enhances adherence of SC on the matrix via the Hep2 region of EDA+ FN.

Competition between c-fos and 1,25(OH)2 vitamin D3 in the transcriptional control of type I collagen synthesis in MC3T3-E1 osteoblastic cells

Interaction between c-fos and 1,25(OH)2 vitamin D3 (VD) on the type I collagen synthesis was studied. VD inhibited collagen synthesis and type I collagen mRNA expression in MC3T3-E1 osteoblastic cells. In contrast, VD reversed the inhibition of collagen synthesis and mRNA expression of the c-fos transfectants that overexpressed c-fos gene to a comparable level as those of the control transfectants. The gel shift assay showed the vitamin D receptor (VDR) complex binding to vitamin D responsive element (VDRE) was inhibited under constitutively expressed c-fos gene, suggesting that c-fos gene product, c-Fos, may inhibit the binding of VDR complex to VDRE by making a c-Fos-VDR complex. The result suggests the existence of a fine tuning between c-fos and VD in the bone metabolism which may be relevant to the pathogenesis of rheumatoid bone lesion.

EDA-containing fibronectin is synthesized from rheumatoid synovial fibroblast-like cells

OBJECTIVE

To identify the cells that synthesize EDA-containing fibronectin (FN) and examine the role of EDA+FN in the pathogenesis of rheumatoid joint lesions.

METHODS

Localization of EDA+FN and c-Fos protein in rheumatoid joints was studied immunohistochemically by utilizing antibodies for EDA+FN and c-Fos. Expression of EDA+FN was studied by immunoelectron microscopy and in situ hybridization. The amount of EDA+FN was measured by enzyme-linked immunosorbent assay.

RESULTS

EDA+FN was specifically localized in the synovial lining layer of synovium with active rheumatoid arthritis (RA) (n = 17), but not in that with osteoarthritis (n = 4) or with inactive fibrous RA (n = 2). EDA+FN messenger RNA was localized in the synovial lining layer. EDA+FN was immunoelectron microscopically localized in the synovial lining fibroblast-like (type B) cells. EDA+FN was also detected at the cartilage-pannus junction and on the surface of RA cartilage. Double staining showed that EDA+FN colocalized with c-Fos protein in the rheumatoid synovial lining layer. Quantification of EDA+FN showed that it was highly concentrated in rheumatoid synovial fluids.

CONCLUSION

EDA+FN is synthesized by the synovial lining fibroblast-like (type B) cells in situ in rheumatoid synovium, and appears to be expressed in association with activated or transformed states of synovium.

Persistent expression of proto-oncogene c-fos stimulates osteoclast differentiation

We analyzed c-fos mRNA expression by northern blotting analysis in chicken osteoclast precursors which spontaneously differentiate to multinucleated osteoclasts in 5-6 days. Osteoclast precursors as well as mature multinucleated osteoclasts showed constitutive expression of c-fos mRNA which is not found in osteoblasts. The c-fos expression was enhanced transiently by serum, dibutyryl cAMP (10(-4) M) and phorbol 12-myristate 13-acetate (TPA) (5 x 10(-7) M). To clarify the role of c-fos in osteoclast differentiation, c-fos DNA was transfected into osteoclast precursors. Greater than 2 fold increases in tartrate resistant acid phosphatase (TRAP) and bone resorptive activity were observed in the transfected cells compared to controls 3 days after transfection, suggesting that prolonged expression of c-fos caused enhanced osteoclast differentiation.