Ken Ei Sada

Increased activity and expression of histone deacetylase 1 in relation to tumor necrosis factor-alpha in synovial tissue of rheumatoid arthritis

IntroductionThe purpose of this study was to investigate the profile of histone deacetylase (HDAC) expression in the synovial tissue of rheumatoid arthritis (RA) compared with that of normal control and osteoarthritis (OA), and to examine whether there is a link between HDAC activity and synovial inflammation.MethodsHDAC activity and histone acetyltransferase (HAT) activity were determined in nuclear extracts of total synovial tissue surgically obtained from normal, OA and RA joints. The level of cytoplasmic tumor necrosis factor a (TNFα) fraction was measured by ELISA. Total RNA of synovial tissue was used for RT-PCR of HDAC1-8. In synovial fibroblasts from RA (RASFs), the effects of TNFα on nuclear HDAC activity and class I HDACs (1, 2, 3, 8) mRNA expressions were examined by quantitative real-time PCR. The protein expression and distribution of class I HDACs were examined by Western blotting.ResultsNuclear HDAC activity was significantly higher in RA than in OA and normal controls and correlated with the amount of cytoplasmic TNFα. The mRNA expression of HDAC1 in RA synovial tissue was higher than in OA and normal controls, and showed positive correlation with TNFα mRNA expression. The protein level of nuclear HDAC1 was higher in RA synovial tissue compared with OA synovial tissue. Stimulation with TNFα significantly increased the nuclear HDAC activity and HDAC1 mRNA expression at 24 hours and HDAC1 protein expression at 48 hours in RASFs.ConclusionsOur results showed nuclear HDAC activity and expression of HDAC1 were significantly higher in RA than in OA synovial tissues, and they were upregulated by TNFα stimulation in RASFs. These data might provide important clues for the development of specific small molecule HDAC inhibitors.

Simvastatin inhibits osteoclast differentiation induced by bone morphogenetic protein-2 and RANKL through regulating MAPK, AKT and Src signaling

The mevalonate pathway plays a crucial role in bone metabolism. Here we examined roles of simvastatin in osteoclast function and differentiation induced by RANKL and BMP-2 using mouse macrophage-like MLC-6 cells and human osteoclast precursor cells. MLC-6 cells expressed BMP type-I and -II receptors and Smads as well as osteoclast markers including TRAP, RANK, cathepsin-K, M-CSF receptor, MMP-9 and calcitonin receptor. Treatment with RANKL and BMP-2 acted synergistically to stimulate RANK, TRAP and cathepsin-K expression in MLC-6 cells. Simvastatin suppressed osteoclastic activity shown by increases in RANK, TRAP and cathepsin-K expression induced by RANKL and BMP-2. In contrast simvastatin alone had no effects on the osteoclastic markers in MLC-6 cells. Simvastatin activated ERK, SAPK/JNK and AKT pathways and inactivated Ras in MLC-6 cells. Simvastatin had no effect on BMP-induced Smad1/5/8 phosphorylation regardless of RANKL stimulation. Since chemical inhibition of ERK, SAPK/JNK and AKT increased TRAP and cathepsin-K expression induced by BMP-2 and RANKL, these pathways are functionally involved in inhibition of osteoclastic activity. In addition, Src phosphorylation induced by RANKL, which is involved in osteoclast differentiation, was suppressed by simvastatin. We further confirmed an inhibitory mechanism of simvastatin on osteoclast differentiation using human osteoclast precursor cells which express BMP receptor and Smad signaling machinery. Simvastatin also activated ERK pathways and inactivated Src phosphorylation in human osteoclasts differentiated by M-CSF and RANKL treatments. The inhibition of TRAP and RANK expression by simvastatin was reversed by ERK inhibition, whereas Src inhibitor enhanced simvastatin-induced suppression of osteoclast markers. Collectively, our data show that simvastatin inhibits osteoclastic differentiation through inhibiting Src as well as enhancing MAPK/AKT pathways.

Estrogen and glucocorticoid regulate osteoblast differentiation through the interaction of bone morphogenetic protein-2 and tumor necrosis factor-α in C2C12 cells

Imbalanced functions between osteoclasts and osteoblasts are involved in inflammatory bone damage. The clinical effectiveness of blocking TNF-alpha in treatment of active rheumatoid arthritis established the significance of TNF-alpha in the pathogenesis. In the present study, we investigated the cellular mechanism by which estrogen and glucocorticoid interact in osteoblastic differentiation regulated by BMP and TNF-alpha using mouse myoblastic C2C12 cells. The expression of estrogen receptors, (ER)alpha and ERbeta, and glucocorticoid receptor (GCR) was significantly increased by BMP-2 treatment regardless of the presence of estradiol and dexamethasone. Estradiol, but not dexamethasone, enhanced BMP-induced Runx2 and osteocalcin expression in C2C12 cells. In addition, TNF-alpha suppressed BMP-2-induced Runx2 and osteocalcin expression, and estradiol and dexamethasone reversed the TNF-alpha effects on BMP-2-induced Runx2 expression. Dexamethasone also abolished osteocalcin expression induced by BMP-2. Interestingly, BMP-2-induced Smad1/5/8 phosphorylation and Id-1 promoter activity were enhanced by estradiol pretreatment. On the other hand, dexamethasone suppressed BMP-2-induced Smad1/5/8 activation. TNF-alpha-induced SAPK/JNK activity was suppressed by estradiol, while NFkappaB phosphorylation was inhibited by dexamethasone. Of note, the inhibitory effects of TNF- on BMP-2-induced Runx2 and osteocalcin expression were reversed by SAPK/JNK inhibition regardless of the presence of estradiol. The estradiol effects that enhance BMP-2-induced Runx2 and osteocalcin mRNA expression were restored by antagonizing ER, and moreover, membrane-impermeable estradiol-BSA failed to enhance the BMP-2-induced osteoblastic differentiation. Thus, estrogen and glucocorticoid are functionally involved in the process of osteoblast differentiation regulated by BMPs and TNF-alpha. BMP-2 increases the sensitivities of ERs and GCR, whereas estrogen and glucocorticoid differentially regulate BMP-Smad and TNF-alpha signaling.

Estrogen facilitates osteoblast differentiation by upregulating bone morphogenetic protein-4 signaling.

Imbalanced functions of osteoclasts and osteoblasts are involved in various types of bone damage including postmenopausal osteoporosis. In the present study, we investigated the cellular mechanism by which estrogen interacts in the process of osteoblastic differentiation regulated by BMP-4 using mouse MC3T3-E1 cells that express estrogen receptors (ER) and BMP-4. Estradiol enhanced BMP-4-induced Runx2, osterix, ALP and osteocalcin expression in MC3T3-E1 cells. BMP-4-induced mineralization shown by Alizarin red staining was also facilitated by estrogen treatment. It was revealed that estrogen upregulated BMP-4-induced Smad1/5/8 phosphorylation, BRE-Luc activity and Id-1 mRNA expression. The expression of BMPRII was increased by estrogen in MC3T3-E1 cells, and inhibition of BMPRII or ALK-2/3 signaling impaired the effect of estrogen on BMP-4 signaling. Of note, the enhanced expression of osterix, ALP and osteocalcin mRNAs induced by BMP-4 and estrogen was reversed in the presence of an ER antagonist. Given that membrane-impermeable estrogen also upregulated BMP-4-induced expression of osteoblastic markers and Id-1 mRNA, non-genomic ER activity is involved in the mechanism by which estrogen enhances BMP-4-induced osteoblast differentiation in MC3T3-E1 cells. On the other hand, the expression of ERα and endogenous BMP-4 was suppressed by BMP-4 treatment regardless of the presence of estrogen, implying the presence of a negative feedback loop for osteoblast differentiation. Thus, estrogen is functionally involved in the process of osteoblast differentiation regulated by BMP-4 through upregulating BMP sensitivity of MC3T3-E1 cells.

A nationwide survey on the epidemiology and clinical features of eosinophilic granulomatosis with polyangiitis (Churg-Strauss) in Japan

Abstract Objective. We conducted a cross-sectional nationwide survey to determine eosinophilic granulomatosis with polyangiitis (Churg-Strauss) (EGPA) prevalence and clinical features in Japan. Methods. Data for EGPA patients in 2008 were collected from 1,564 hospitals. In total, 965 patients were reported from 365 departments. In a second survey, clinical data for 473 patients were obtained. Results. We estimated that 1,866 (95% CI: 1,640–2,092) patients have EGPA in Japan (prevalence, 17.8/1,000,000). Of the 473 patients in the second survey, 315 fulfilled American College of Rheumatology (ACR) criteria or Lanhams criteria for EGPA. The mean age (± SD) of the 315 at onset was 55 ± 14 years, male to female ratio 1:2. 93% of patients had neurological manifestations, which were the organ system most frequently involved. Among 277 patients tested for myeloperoxidase (MPO)-/p anti-neutrophil cytoplasmic antibody (ANCA), 139 (50%) were positive, while only 6 of 238 were positive for proteinase3 (PR3)-/cANCA. MPO-ANCA-positive patients had renal involvement, mucous membrane or ophthalmological symptoms, and ENT symptoms more frequently, whereas cutaneous lesions and cardiovascular involvement were less common. Conclusion. The prevalence of EGPA and the frequency of MPO-/p-ANCA-positivity in Japanese EGPA patients were mostly similar to those of Western countries. However, female predominance and a high frequency of neurological manifestations characterized Japanese patients.

Current Concept and Epidemiology of Systemic Vasculitides

Although a new classification algorithm for systemic vasculitides was proposed by Watts et al. and the Chapel Hill Consensus Conference (CHCC) was updated in 2012, there are currently no validated diagnostic criteria for systemic vasculitides. The Diagnostic and Classification Criteria for Vasculitis study (DCVAS) is a global study to develop and improve the diagnostic criteria for systemic vasculitides. The epidemiology of systemic vasculitides differs widely among countries. For example, in the case of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, patients with microscopic polyangiitis (MPA) and with positivity for MPO-ANCA are predominant in Asian countries, whereas patients with granulomatosis with polyangiitis (GPA) and with positivity for PR3-ANCA are predominant in northern Europe and the United States. Interstitial lung disease (ILD) occurs more frequently in Asian patients compared with patients in Europe. The incidence and the prevalence of large-vessel vasculitis also differ significantly. Giant cell arteritis (GCA) occurs frequently in northern Europe, unlike Takayasu arteritis (TAK). The ethnic and regional differences in the incidence, prevalence and clinical characteristics of patients with vasculitis should be recognized when we diagnose and treat patients with vasculitis using criteria, and should also be considered when interpreting the results from clinical studies.

Risk Factors Associated with Relapse in Japanese Patients with Microscopic Polyangiitis

Objective. We retrospectively studied the risk factors associated with relapse during remission maintenance therapy for myeloperoxidase-antineutrophil cytoplasmic autoantibody (MPO-ANCA)-positive microscopic polyangiitis (MPA). Methods. Sixty-two patients diagnosed with MPA according to the European Medicines Agency classification algorithm during a 2-year period from January 1, 2005, to December 31, 2006, and who achieved remission after the first remission-induction therapy, were examined (registration no. UMIN000001785). Results. The patient group comprised 25 men and 37 women aged 70.0 ± 8.9 years. The mean observation period was 30.2 ± 15.9 months. The rate of relapse was 24.2% (15/62), and mean interval between remission and relapse was 16.9 ± 13.5 months. During maintenance therapy following remission, the risk of relapse increased when the reduction rate of prednisolone increased above 0.8 mg/month (OR 12.6, 95% CI 2.2–97.9). Proteinuria at the start of maintenance therapy (regression coefficient 1.991 ± 0.758, p < 0.05) and the change in red blood cell counts in urine during the period from the start of maintenance therapy to the final observation (regression coefficient 0.126 ± 0.040, p < 0.01) were identified as risk factors influencing the vasculitis damage index. Conclusion. In Japan, relapse of MPO-ANCA-positive MPA may be associated with the reduction rate of oral prednisolone administration during maintenance therapy.

Peroxisome proliferator-activated receptor activity is involved in the osteoblastic differentiation regulated by bone morphogenetic proteins and tumor necrosis factor-α.

Recent studies have suggested possible adverse effects of thiazolidinediones on bone metabolism. However, the detailed mechanism by which the activity of PPAR affects bone formation has not been elucidated. Impaired osteoblastic function due to cytokines is critical for the progression of inflammatory bone diseases. In the present study, we investigated the cellular mechanism by which PPAR actions interact with osteoblast differentiation regulated by BMP and TNF-α using mouse myoblastic C2C12 cells. BMP-2 and -4 potently induced the expression of various bone differentiation markers including Runx2, osteocalcin, type-1 collagen and alkaline phosphatase (ALP) in C2C12 cells. When administered in combination with a PPARα agonist (fenofibric acid) but not with a PPARγ agonist (pioglitazone), BMP-4 enhanced osteoblast differentiation through the activity of PPARα. The osteoblastic changes induced by BMP-4 were readily suppressed by treatment with TNF-α. Interestingly, the activities of PPARα and PPARγ agonists reversed the suppression by TNF-α of osteoblast differentiation induced by BMP-4. Furthermore, TNF-α-induced phosphorylation of MAPKs, NFκB, IκB and Stat pathways was inhibited in the presence of PPARα and PPARγ agonists with reducing TNF-α receptor expression. In view of the finding that inhibition of SAPK/JNK, Stat and NFκB pathways reversed the TNF-α suppression of osteoblast differentiation, we conclude that these cascades are functionally involved in the actions of PPARs that antagonize TNF-α-induced suppression of osteoblast differentiation. It was further discovered that the PPARα agonist enhanced BMP-4-induced Smad1/5/8 signaling through downregulation of inhibitory Smad6/7 expression, whereas the PPARγ agonist impaired this activity by suppressing BMPRII expression. On the other hand, BMPs increased the expression levels of PPARα and PPARγ in the process of osteoblast differentiation. Thus, PPARα actions promote BMP-induced osteoblast differentiation, while both activities of PPARα and PPARγ suppress TNF-α actions. Collectively, our present data establishes that PPAR activities are functionally involved in modulating the interaction between the BMP system and TNF-α receptor signaling that is crucial for bone metabolism.

Good response of membranous lupus nephritis to tacrolimus.

A 22-year-old woman hospitalized for polyarthralgia was diagnosed with systemic lupus erythematosus (SLE). She was treated with prednisolone, and her clinical manifestations improved. However, she was re-admitted for renal biopsy because of persistent hypocomplementemia and development of proteinuria. The biopsy revealed segmental spike formation of basement membrane and subepithelial immune complex deposition, and membranous lupus nephritis (class V) was diagnosed. When tacrolimus was added to prednisolone, the serum complement titer quickly improved and proteinuria disappeared after about 11 months. Nevertheless, when tacrolimus was replaced examination showed cyclosporine due to gastrointestinal symptoms, she complained about arthralgia. Examination showed drop in the serum complement titer and recurrence of proteinuria. Renal biopsy at the time of recurrence showed increased subepithelial immune complex deposition in the capillary loops as compared to the first biopsy, a high degree of thickening of the basement membrane, and segmental circumferential interposition in some of the glomeruli. Membranous lupus nephritis (classes V + III) was diagnosed. By changing to tacrolimus and higher doses of steroids, the serum complement titer improved and proteinuria disappeared. This case indicates that tacrolimus can be an effective therapeutic agent for membranous lupus nephritis.

Risk factors for the development of glucocorticoid-induced diabetes mellitus

AIMS To evaluate the incidence of glucocorticoid-induced diabetes mellitus (GC-DM) by repeated measurements of the postprandial glucose and detect predictors for the development of GC-DM. METHODS Inpatients with rheumatic or renal disease who received glucocorticoid therapy were enrolled in this study. We compared the clinical and laboratory parameters of the GC-DM group with the non-GC-DM group and performed a multivariate analysis to identify risk factors. RESULTS During a four-week period, 84 of the 128 patients (65.6%) developed GC-DM. All patients were diagnosed based on the detection of postprandial hyperglycemia. The GC-DM group had an older age (65.2 vs. 50.4 years, p<0.0001), higher levels of fasting plasma glucose (93.3 vs. 89.0mg/dl, p=0.027) and HbA1c (5.78 vs. 5.50%, 39.7 vs. 36.6 mmol/mol, p=0.001) and lower eGFR values (54.0 vs. 77.1 ml/min/1.73 m(2), p=0.0003) than the non-GC-DM group. According to the multivariate analysis, an older age (more than or equal to 65 years), higher HbA1c level (more than or equal to 6.0%) and lower eGFR (<40 ml/min/1.73m(2)) were identified as independent risk factors for GC-DM (OR 2.95, 95% CI 1.15-7.92, OR: 3.05, 95% CI 1.11-9.21, OR: 3.42, 95% CI: 1.22-10.8, respectively). The risk ratio for the development of GC-DM in the patients with at least one of these three risk factors was 2.28. The dose of glucocorticoids was not statistically related to the development of GC-DM. CONCLUSIONS Patients with an older age, higher HbA1c level and lower eGFR require close monitoring for the development of GC-DM, regardless of the dose of glucocorticoids being administered.