bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of autophagy in human and murine cartilage: Hypoxia‐inducible factor 2 suppresses chondrocyte autophagy
Authors: Bohensky Jolene , Terkhorn Shawn P. , Freeman Theresa A. , Adams Christopher S. , Garcia Joseph A. , Shapiro Irving M. , Srinivas Vickram
Published: April 2009

Objective

We have previously demonstrated that the transcription factor hypoxia‐inducible factor 1 (HIF‐1) promotes the onset of autophagy in chondrocytes. The overall goal of this study was to test the hypothesis that another HIF family transcription factor, HIF‐2, modulates the induction of autophagy by chondrocytes.

Methods

Expression of HIF‐1, HIF‐2, and light chain 3 (LC3) in human and murine articular cartilage was visualized by immunohistochemistry. Suppression of HIF‐2 was achieved using small interfering RNA technology. Assessments of autophagic flux and lysosomal activity, as well as ultrastructural analysis, were performed in chondrocytes in cell culture.

Results

HIF‐2 was expressed abundantly by cells in human and murine articular cartilage and in the cartilage of mineralizing vertebrae from neonatal mice. Protein levels were reduced in articular cartilage from older mice, in end‐plate cartilage from mice, and in chondrocytes from human osteoarthritic (OA) cartilage. HIF‐2 was robustly expressed in the prehypertrophic cells of mouse growth cartilage. When HIF‐2α was silenced, the generation of reactive oxygen species was found to be elevated, with a concomitant decrease in catalase and superoxide dismutase activity. Suppression of HIF‐2 was associated with decreased Akt‐1 and mammalian target of rapamycin activities, reduced Bcl‐xL expression, and a robust autophagic response, even under nutrient‐replete conditions. In these silenced chondrocytes, HIF‐1 expression was elevated. Decreased HIF‐2 expression was associated with autophagy in OA tissues and aging cartilage samples. The autophagic response of chondrocytes in HIF‐2α–knockout mouse growth plate showed an elevated autophagic response throughout the plate.

Conclusion

Based on these observations, we conclude that HIF‐2 is a potent regulator of autophagy in maturing chondrocytes. Our data suggest that this protein acts as a brake on the autophagy‐accelerator function of HIF‐1.
Indoleamine 2,3 dioxygenase–mediated tryptophan catabolism regulates accumulation of Th1/Th17 cells in the joint in collagen‐induced arthritis
Authors: Criado Gabriel , Šimelyte Egle , Inglis Julia J. , Essex David , Williams Richard O.
Published: April 2009

Objective

Indoleamine 2,3 dioxygenase (IDO) is a catabolic enzyme that initiates the kynurenine pathway of tryptophan degradation and has immunomodulatory properties. The aim of this study was to investigate the regulation of collagen‐induced arthritis by tryptophan catabolism mediated by IDO.

Methods

Arthritis was induced by immunization with type II collagen. After induction of arthritis, the expression of IDO was analyzed by quantitative reverse transcription–polymerase chain reaction. The effect of IDO deficiency on collagen‐induced arthritis was assessed in vivo by administration of 1‐methyltryptophan and clinical and histologic evaluation of IDO‐deficient mice. The requirement for IDO activation was bypassed by administration of L‐kynurenine.

Results

IDO was induced in lymph node dendritic cells after collagen immunization. Systemic inhibition of tryptophan catabolism during active arthritis increased disease severity. Conversely, bypassing the requirement for tryptophan degradation by the administration of L‐kynurenine resulted in amelioration of arthritis. Furthermore, IDO‐deficient mice showed a higher incidence of arthritis and exacerbated disease severity compared with IDO‐competent mice. Such increased disease activity in IDO‐deficient mice correlated early with increased production of the proinflammatory cytokines interferon‐γ and interleukin‐17 by lymph node T cells and later with increased infiltration of Th1 and Th17 cells in the inflamed joints.

Conclusion

Our data indicate that the induction of IDO controls the accumulation of Th1 and Th17 pathogenic T cells at the site of inflammation during collagen‐induced arthritis. Therefore, manipulation of the kynurenine pathway of tryptophan degradation provides the potential for therapeutic intervention in rheumatoid arthritis.
Gene expression profiling in neutrophils from children with polyarticular juvenile idiopathic arthritis
Authors: Jarvis James N. , Jiang Kaiyu , Frank Mark Barton , Knowlton Nicholas , Aggarwal Amita , Wallace Carol A. , McKee Ryan , Chaser Brad , Tung Catherine , Smith Laura B. , McGhee Julie L. , Chen Yanmin , Osban Jeanette , O'Neil Kathleen M. , Centola Michael
Published: April 2009

Objective

We have previously reported a defect in neutrophil activation in children with polyarticular juvenile idiopathic arthritis (JIA). The current study was undertaken to determine whether gene expression abnormalities persist in JIA in remission and to use systems biology analysis to elucidate pathologic pathways in polyarticular JIA.

Methods

We performed gene expression profiling on neutrophils from children with polyarticular JIA. Children were grouped according to disease status. We studied 14 children with active disease who were taking medication, 8 children with clinical remission of disease who were taking medication (CRM status), and 6 children with clinical remission of disease who were not taking medication (CR status). We also studied 13 healthy children whose age ranges overlapped those of the patients.

Results

Neutrophil abnormalities persisted in children with polyarticular JIA even after disease remission was achieved. Children with active disease and those with CRM status showed no differences in expression of specific genes, although they could be separated on cluster analysis. A comparison of children with CR status and healthy control children revealed networks of pro‐ and antiinflammatory genes that suggested that remission is a state of homeostasis and balance rather than a return to normal immune function. Furthermore, gene overexpression in patients with CR status supports the hypothesis that neutrophils play a role in regulating adaptive immunity in this disease.

Conclusion

Neutrophil gene profiling in polyarticular JIA suggests important roles for neutrophils in disease pathogenesis. These findings suggest the presence of complex interactions between innate and adaptive immunity, that are not easily modeled in conventional, linear, reductionist systems.
Oncostatin M–induced CCL2 transcription in osteoblastic cells is mediated by multiple levels of STAT‐1 and STAT‐3 signaling: An implication for the pathogenesis of arthritis
Authors: Kok Sang‐Heng , Hong Chi‐Yuan , Kuo Mark Yen‐Ping , Wang Chih‐Chiang , Hou Kuo‐Liang , Lin Yi‐Ting , Galson Deborah L. , Lin Sze‐Kwan
Published: April 2009

Objective

To examine the roles of STATs 1 and 3 in CCL2 production in human osteoblastic cells and their influences on arthritis development.

Methods

The expression of CCL2 in primary human osteoblasts and U2OS human osteoblastic cells was examined by Northern blotting and enzyme‐linked immunosorbent assay. The roles of STAT‐1/3 and c‐Fos were assessed using short hairpin RNAs (shRNA) to silence their functions. Serine phosphorylation of STATs was assessed by Western blotting. Promoter activities of c‐Fos and CCL2 were assessed by chloramphenicol acetyltransferase and luciferase assays, respectively. Interactions of STAT‐1, STAT‐3, and c‐Fos with DNA were evaluated by electrophoretic mobility shift assay (EMSA) and immunoprecipitation. The effect of the JAK inhibitor AG‐490 on collagen‐induced arthritis (CIA) in rats was examined using immunohistochemistry.

Results

Oncostatin M (OSM) stimulated CCL2 expression in primary human osteoblasts and U2OS cells. In U2OS cells, STAT‐1 and STAT‐3 were involved in OSM‐stimulated CCL2 expression, and both the phosphatidylinositol 3‐kinase/Akt and MEK/ERK pathways were implicated in the activation of these STATs. STAT‐1 and STAT‐3 modulated the expression of c‐Fos and directly transactivated the CCL2 promoter. Moreover, EMSA showed formation of a DNA–protein complex containing STAT‐1, STAT‐3, and interestingly, c‐Fos. Immunoprecipitation confirmed the binding between c‐Fos and STAT‐1/3. Reporter assay revealed synergistic attenuation of CCL2 promoter activity by shRNA targeting of STAT‐1, STAT‐3, and c‐Fos. AG‐490 suppressed OSM‐stimulated activation of STAT‐1/3 and synthesis of CCL2 in vitro and diminished the severity of CIA and the number of CCL2‐synthesizing osteoblasts in vivo.

Conclusion

These findings show that multiple levels of STAT‐1/3 signaling modulate OSM‐stimulated CCL2 expression in human osteoblastic cells. Clinically, this pathway may be related to the pathogenesis of arthritis.
Rituximab is effective in the treatment of refractory ophthalmic Wegener's granulomatosis
Authors: Taylor Simon R. J. , Salama Alan D. , Joshi Lavnish , Pusey Charles D. , Lightman Susan L.
Published: April 2009

Objective

To investigate the efficacy of rituximab in patients with refractory ophthalmic Wegener's granulomatosis (WG).

Methods

Data from 10 consecutive patients with refractory ophthalmic WG treated with rituximab were retrospectively reviewed. In all patients, the ophthalmic disease was driving treatment decisions, and disease activity had persisted despite standard immunosuppressive treatment. Patients had refractory scleritis (n = 3), orbital granulomas causing optic nerve compromise (n = 4), or a combination of both conditions (n = 3). All patients had been treated with at least 3 different immunosuppressive agents, and 5 patients had previously been treated with tumor necrosis factor α blockade. Rituximab was administered intravenously in 2 doses, 2 weeks apart, in combination with standard treatment. Disease activity was monitored clinically by an interdisciplinary approach, including disease activity scoring, immunodiagnostics, and magnetic resonance imaging, as well as by corresponding reductions in the required dose of conventional medication.

Results

A beneficial response to treatment with rituximab was seen in all 10 patients, including induction of clinical remission. In all patients, the peripheral blood B cell count fell to zero during treatment with rituximab. Titers of classic antineutrophil cytoplasmic antibodies fell in association with B cell counts, and this reduction was correlated with improved clinical findings.

Conclusion

In contrast to previous observations, this study showed that treatment with rituximab was associated with clinical improvement in patients with refractory ophthalmic WG.
The high prevalence of knee osteoarthritis in a rural Chinese population: The Wuchuan osteoarthritis study
Authors: Kang Xiaozheng , Fransen Marlene , Zhang Yuqing , Li Hu , Ke Yan , Lu Ming , Su Steve , Song Xiongying , Guo Yong , Chen Jie , Niu Jingbo , Felson David , Lin Jianhao
Published: April 2009

Objective

To estimate the prevalence of radiographic and symptomatic knee osteoarthritis (OA) in a remote rural region of northern China, and compare them with those reported in Beijing and with data from the Framingham (Massachusetts) cohort.

Methods

A population‐based cross‐sectional survey was conducted among 1,030 residents of Wuchuan County, Inner Mongolia, age ≥50 years. Survey participants, mostly farmers reporting heavy physical occupational activity, completed an interviewer‐based questionnaire, and bilateral weight‐bearing posteroanterior semiflexed knee radiographs were obtained.

Results

Whereas the overall prevalence of radiographic knee OA was similar to that demonstrated in the Beijing OA study, men in Wuchuan had approximately double the prevalence of severe radiographic knee OA (prevalence ratio [PR] 2.5, 95% confidence interval [95% CI] 1.6–3.8) and symptomatic knee OA (PR 1.9, 95% CI 1.3–2.9). Women in Wuchuan also had a higher prevalence of both severe radiographic (PR 1.4, 95% CI 1.0–2.0) and symptomatic knee OA (PR 1.6, 95% CI 1.2–2.1) compared with their Beijing counterparts. The prevalence of bilateral OA and lateral compartment disease were 2–3 times higher in both Chinese cohorts compared with estimates from the Framingham OA study.

Conclusion

The prevalence of symptomatic knee OA in rural areas of China is much higher than reported from urban regions of China or in the Framingham cohort. The higher representation of bilateral and lateral compartment disease in China suggests a unique phenotype to OA. These findings will be useful for guiding the distribution of future health care resources and preventive strategies.

This article was published online on April 29, 2009. The incorrect figure was published for Figure 1. This notice is included in the online and print versions to indicate that both have been corrected.
Association of a specific ERAP1/ARTS1 haplotype with disease susceptibility in ankylosing spondylitis
Authors: Maksymowych W. P. , Inman R. D. , Gladman D. D. , Reeve J. P. , Pope A. , Rahman P.
Published: April 2009

Objective

Alterations in antigen processing have been proposed to play a significant role in the pathogenesis of ankylosing spondylitis (AS). A non–major histocompatibility complex gene encoding an endoplasmic reticulum aminopeptidase, ERAP1, has been implicated recently. This study assessed 13 coding single‐nucleotide polymorphisms (SNPs) from 5 genes involved in antigen processing (ERAP1, TAP1, TAP2, LMP2, and LMP7) in 3 Canadian cohorts of patients with AS, to address the possibility of gene interactions in disease susceptibility.

Methods

The study involved 992 AS cases and 1,437 controls from 3 centers (472 cases and 451 controls from Alberta, 138 cases and 392 controls from Newfoundland, and 382 cases and 594 controls from Toronto). Most of the patients with AS and healthy, unrelated controls were Caucasians of northern European descent. Single‐marker and haplotype associations were determined using an allelic likelihood ratio test in UNPHASED, version 3.0.12, and the WHAP program, respectively. P values for significance of haplotype associations were calculated using a permutation test.

Results

A specific ERAP1 haplotype, rs27044/10050860/30187‐CCT, was strongly associated with increased risk of AS in all 3 case–control cohorts (pooled odds ratio [OR] 1.81, 95% confidence interval [95% CI] 1.46–2.24; P = 7 × 10−8), while a second specific ERAP1 haplotype, rs30187/26618/26653‐CTG, reduced the disease risk (pooled OR 0.77, 95% CI 0.67–0.88; P = 9 × 10−5). Significant associations were also noted for 3 ERAP1 SNP variants (rs10050860, rs30187, and rs26653), although no significant haplotype interaction between ERAP1 and TAP/LMP loci was evident.

Conclusion

These data indicate that an AS disease locus may reside on a specific ERAP1 haplotype, and its effect is not multiplicative with contributions from TAP and LMP genes.
Premature atherosclerosis in pediatric systemic lupus erythematosus: Risk factors for increased carotid intima‐media thickness in the atherosclerosis prevention in pediatric lupus erythematosus cohort
Authors: Schanberg Laura E. , Sandborg Christy , Barnhart Huiman X. , Ardoin Stacy P. , Yow Eric , Evans Gregory W. , Mieszkalski Kelly L. , Ilowite Norman T. , Eberhard Anne , Levy Deborah M. , Kimura Yukiko , von Scheven Emily , Silverman Earl , Bowyer Suzanne L. , Punaro Lynn , Singer Nora G. , Sherry David D. , McCurdy Deborah , Klein‐Gitelman Marissa , Wallace Carol , Silver Richard , Wagner‐Weiner Linda , Higgins Gloria C. , Brunner Hermine I. , Jung Lawrence , Soep Jennifer B. , Reed Ann ,   Atherosclerosis Prevention in Pediatric Lupus Erythematosus Investigators
Published: April 2009

Objective

To evaluate risk factors for subclinical atherosclerosis in a population of patients with pediatric systemic lupus erythematosus (SLE).

Methods

In a prospective multicenter study, a cohort of 221 patients underwent baseline measurements of carotid intima‐media thickness (CIMT) as part of the Atherosclerosis Prevention in Pediatric Lupus Erythematosus (APPLE) trial. SLE disease measures, medications, and traditional risk factors for atherosclerosis were assessed. A standardized protocol was used to assess the thickness of the bilateral common carotid arteries and the mean maximal IMT of 12 segments. Univariable analysis identified potential associations with CIMT, which were examined in multivariable linear regression modeling.

Results

Based on the mean‐mean common or the mean‐max CIMT as the dependent variable, univariable analysis showed significant associations of the following variables with increased CIMT: increasing age, longer SLE duration, minority status, higher body mass index (BMI), male sex, increased creatinine clearance, higher lipoprotein(a) level, proteinuria, azathioprine treatment, and prednisone dose. In multivariable modeling, both azathioprine use (P = 0.005 for the mean‐mean model and P = 0.102 for the mean‐max model) and male sex (P < 0.001) were associated with increases in the mean‐max CIMT. A moderate dosage of prednisone (0.15–0.4 mg/kg/day) was associated with decreases in the mean‐max CIMT (P = 0.024), while high‐dose and low‐dose prednisone were associated with increases in the mean‐mean common CIMT (P = 0.021) and the mean‐max CIMT (P = 0.064), respectively. BMI (P < 0.001) and creatinine clearance (P = 0.031) remained associated with increased mean‐mean common CIMT, while increasing age (P < 0.001) and increasing lipoprotein(a) level (P = 0.005) were associated with increased mean‐max CIMT.

Conclusion

Traditional as well as nontraditional risk factors were associated with increased CIMT in this cohort of patients in the APPLE trial. Azathioprine treatment was associated with increased CIMT. The relationship between CIMT and prednisone dose may not be linear.
The α7 nicotinic acetylcholine receptor on fibroblast‐like synoviocytes and in synovial tissue from rheumatoid arthritis patients: A possible role for a key neurotransmitter in synovial inflammation
Authors: Maanen Marjolein A. Van , Stoof Susanne P. , Zanden Esmerij P. Van Der , Jonge Wouter J. De , Janssen Richard A. , Fischer David F. , Vandeghinste Nick , Brys Reginald , Vervoordeldonk Margriet J. , Tak Paul P.
Published: April 2009

Objective

Recent studies have suggested an important role for neurotransmitters as modulators of inflammation. Therefore, we undertook this study to investigate the expression of the α7 subunit of the nicotinic acetylcholine receptor (α7nAChR) and its function in rheumatoid arthritis (RA).

Methods

The potential role of the α7nAChR in modulating proinflammatory cytokine expression in fibroblast‐like synoviocytes (FLS) was identified by screening an adenoviral short hairpin RNA (Ad.shRNA) library. An α7‐specific antibody was used for immunohistochemistry, and fluorescein isothiocyanate–labeled α‐bungarotoxin, which binds specifically to the α7nAChR, was used for immunofluorescence. Gene expression in FLS was determined by quantitative polymerase chain reaction with primers specific for the α7nAChR. In addition, we analyzed messenger RNA (mRNA) expression of dupα7, a variant α7 transcript. Next, we studied the functional role of the α7nAChR in RA FLS by examining the effects of α7‐specific agonists on the production of interleukin‐6 (IL‐6) and IL‐8 by activated FLS.

Results

A screen using an Ad.shRNA library against 807 transcripts revealed that a specific α7nAChR shRNA potently modulated IL‐8 and matrix metalloproteinase expression in FLS. The α7nAChR was expressed in the inflamed synovium from RA patients, predominantly in the intimal lining layer. We found α7nAChR expression at both the mRNA and protein level in cultured RA FLS. FLS also constitutively expressed dupα7 mRNA. Specific α7nAChR agonists reduced tumor necrosis factor α–induced IL‐6 and IL‐8 production by FLS.

Conclusion

The α7nAChR and its dupα7 variant are expressed in RA synovium, where they may play a critical role in regulating inflammation. Targeting the α7nAChR could provide a novel antiinflammatory approach to the treatment of RA.
Induction of the expression of profibrotic cytokines and growth factors in normal human peripheral blood monocytes by gadolinium contrast agents
Authors: Wermuth Peter J. , del Galdo Francesco , Jiménez Sergio A.
Published: April 2009

Objective

Nephrogenic systemic fibrosis (NSF) is a severe fibrosing disorder occurring in patients with renal insufficiency. The majority of patients with this disorder have documented exposure to magnetic resonance imaging contrast agents containing Gd. The purpose of this study was to examine the effects of gadolinium diethylenetriaminepentaacetic acid bismethylamide (Gd[DTPA‐BMA]; Omniscan) as compared with Gd‐DTPA and GdCl3 on the expression and production of cytokines and growth factors by normal human peripheral blood monocytes in vitro and to examine whether conditioned media from Gd‐exposed peripheral blood monocytes could induce a profibrotic phenotype in dermal fibroblasts.

Methods

Normal human peripheral blood monocytes isolated by Ficoll‐Hypaque gradient centrifugation and plastic adherence were incubated with various concentrations of Gd[DTPA‐BMA], Gd‐DTPA, or GdCl3. Gene expression of interleukins 4, 6, and 13, interferon‐γ, tumor necrosis factor α, transforming growth factor β, connective tissue growth factor, and vascular endothelial growth factor were assessed by real‐time polymerase chain reaction (PCR) analysis. Production and secretion of cytokines and growth factors by Gd compound–exposed monocytes was quantified by enzyme‐linked immunosorbent assay proteome multiplex arrays. The effects of conditioned media from the Gd compound–exposed monocytes on the phenotype of normal human dermal fibroblasts were examined by real‐time PCR and Western blotting.

Results

The 3 Gd‐containing compounds stimulated the expression and production of numerous cytokines and growth factors by normal human peripheral blood monocytes. Conditioned media from these cells induced a profibrotic phenotype in normal human dermal fibroblasts.

Conclusion

The 3 Gd‐containing compounds studied induce potent cellular responses in normal human peripheral blood monocytes, which may participate in the development of tissue fibrosis in NSF.
Methylation status of CpG islands in the promoter regions of signature genes during chondrogenesis of human synovium–derived mesenchymal stem cells
Authors: Ezura Yoichi , Sekiya Ichiro , Koga Hideyuki , Muneta Takeshi , Noda Masaki
Published: April 2009

Objective

Human synovium–derived mesenchymal stem cells (MSCs) can efficiently differentiate into mature chondrocytes. It has been suggested that DNA methylation is one mechanism that regulates human chondrogenesis; however, the methylation status of genes related to chondrogenic differentiation is not known. The purpose of this study was to investigate the CpG methylation status in human synovium–derived MSCs during experimental chondrogenesis, with a view toward potential therapeutic use in osteoarthritis.

Methods

Human synovium–derived MSCs were subjected to chondrogenic pellet culture for 3 weeks. The methylation status of 12 regions in the promoters of 10 candidate genes (SOX9, RUNX2, CHM1, FGFR3, CHAD, MATN4, SOX4, GREM1, GPR39, and SDF1) was analyzed by bisulfite sequencing before and after differentiation. The expression levels of these genes were analyzed by real‐time reverse transcription–polymerase chain reaction. Methylation status was also examined in human articular cartilage.

Results

Bisulfite sequencing analysis indicated that 10 of the 11 CpG‐rich regions analyzed were hypomethylated in human progenitor cells before and after 3 weeks of pellet culture, regardless of the expression levels of the genes. The methylation status was consistently low in SOX9, RUNX2, CHM1, CHAD, and FGFR3 following an increase in expression upon differentiation and was low in GREM1 and GPR39 following a decrease in expression upon chondrogenesis. One exceptional instance of a differentially methylated CpG‐rich region was in a 1‐kb upstream sequence of SDF1, the expression of which decreased upon differentiation. Paradoxically, the hypermethylation status of this region was reduced after 3 weeks of pellet culture.

Conclusion

The DNA methylation levels of CpG‐rich promoters of genes related to chondrocyte phenotypes are largely kept low during chondrogenesis in human synovium–derived MSCs.
MicroRNA‐124a is a key regulator of proliferation and monocyte chemoattractant protein 1 secretion in fibroblast‐like synoviocytes from patients with rheumatoid arthritis
Authors: Nakamachi Yuji , Kawano Seiji , Takenokuchi Mariko , Nishimura Kunihiro , Sakai Yoshitada , Chin Takaaki , Saura Ryuichi , Kurosaka Masahiro , Kumagai Shunichi
Published: April 2009

Objective

To elucidate the role of microRNA (miRNA) in the pathogenesis of rheumatoid arthritis (RA), we analyzed synoviocytes from RA patients for their miRNA expression.

Methods

Synoviocytes derived from surgical specimens obtained from RA patients were compared with those obtained from osteoarthritis (OA) patients for their expression of a panel of 156 miRNA with quantitative stem‐loop reverse transcription–polymerase chain reaction. The miRNA whose expression decreased or increased in RA synoviocytes as compared with OA synoviocytes were identified, and their target genes were predicted by computer analysis. We used an in vitro system of enhancing the expression of specific miRNA by transfection of precursors into synoviocytes, and then we performed proliferation, cell cycle, and apoptosis assays, as well as enzyme‐linked immunosorbent assays for cytokine production. The effects of transfection on predicted target protein and messenger RNA (mRNA) were then examined by Western blot analysis and luciferase reporter assay.

Results

We found that miR‐124a levels significantly decreased in RA synoviocytes as compared with OA synoviocytes. Transfection of precursor miR‐124a into RA synoviocytes significantly suppressed their proliferation and arrested the cell cycle at the G1 phase. We identified a putative consensus site for miR‐124a binding in the 3′‐untranslated region of cyclin‐dependent kinase 2 (CDK‐2) and monocyte chemoattractant protein 1 (MCP‐1) mRNA. Induction of miR‐124a in RA synoviocytes significantly suppressed the production of the CDK‐2 and MCP‐1 proteins. Luciferase reporter assay demonstrated that miR‐124a specifically suppressed the reporter activity driven by the 3′‐untranslated regions of CDK‐2 and MCP‐1 mRNA.

Conclusion

The results of this study suggest that miR‐124a is a key miRNA in the posttranscriptional regulatory mechanisms of RA synoviocytes.
Generalized Wegener's granulomatosis in an immunocompetent adult after cytomegalovirus mononucleosis and bacterial urinary tract infection
Authors: Varani Stefania , Mastroianni Antonio , Frascaroli Giada , Tammik Charlotte , Rahbar Afsar , Christensson Marta , Rossini Giada , Landini Maria Paola , Söderberg‐Nauclér Cecilia
Published: April 2009

Human cytomegalovirus (HCMV) is frequently detected in autoimmune diseases, but its role in such disorders is poorly understood. Herein we describe the case of a young woman who developed generalized Wegener's granulomatosis (WG) after HCMV mononucleosis and urinary tract infection. During mononucleosis, the patient had extraordinarily high plasma levels of proinflammatory cytokines such as interleukin‐5 and lymphotoxin α, autoantibodies, and a higher blood level of viral DNA than were found in other immunocompetent patients infected with HCMV or healthy controls. Active HCMV replication was detected after the onset of vasculitis, and HCMV genomes or antigens were found in blood, urine, and inflammatory lesions on the kidney. Thus, HCMV may have triggered or exacerbated inflammation and autoimmunity in this case of WG.
Down‐regulation of myeloid cell leukemia 1 by epigallocatechin‐3‐gallate sensitizes rheumatoid arthritis synovial fibroblasts to tumor necrosis factor α–induced apoptosis
Authors: Ahmed Salahuddin , Silverman Matthew D. , Marotte Hubert , Kwan Kevin , Matuszczak Natalie , Koch Alisa E.
Published: April 2009

Objective

Overexpression of the antiapoptotic protein myeloid cell leukemia 1 (Mcl‐1) in rheumatoid arthritis (RA) synovial fibroblasts is a major cause of their resistance to tumor necrosis factor α (TNFα)–induced apoptosis. This study was undertaken to evaluate the efficacy of epigallocatechin‐3‐gallate (EGCG) in down‐regulating Mcl‐1 expression and its mechanism of RA synovial fibroblast sensitization to TNFα‐induced apoptosis.

Methods

EGCG effects on cultured RA synovial fibroblast cell morphology, proliferation, and viability over 72 hours were determined by microscopy and a fluorescent cell enumeration assay. Caspase 3 activity was determined by a colorimetric assay. Western blotting was used to evaluate the apoptosis mediators poly(ADP‐ribose) polymerase (PARP), Mcl‐1, Bcl‐2, Akt, and nuclear translocation of NF‐κB.

Results

In RA synovial fibroblasts, EGCG (5–50 μM) inhibited constitutive and TNFα‐induced Mcl‐1 protein expression in a concentration‐ and time‐dependent manner (P < 0.05). Importantly, EGCG specifically abrogated Mcl‐1 expression in RA synovial fibroblasts and affected Mcl‐1 expression to a lesser extent in osteoarthritis and normal synovial fibroblasts or endothelial cells. Inhibition of Mcl‐1 by EGCG triggered caspase 3 activity in RA synovial fibroblasts, which was mediated via down‐regulation of the TNFα‐induced Akt and NF‐κB pathways. Caspase 3 activation by EGCG also suppressed RA synovial fibroblast growth, and this effect was mimicked by Akt and NF‐κB inhibitors. Interestingly, Mcl‐1 degradation by EGCG sensitized RA synovial fibroblasts to TNFα‐induced PARP cleavage and apoptotic cell death.

Conclusion

Our findings indicate that EGCG itself induces apoptosis and further sensitizes RA synovial fibroblasts to TNFα‐induced apoptosis by specifically blocking Mcl‐1 expression and, hence, may be of promising adjunct therapeutic value in regulating the invasive growth of synovial fibroblasts in RA.
Altered mineralization of human osteoarthritic osteoblasts is attributable to abnormal type I collagen production
Authors: Couchourel Denis , Aubry Isabelle , Delalandre Aline , Lavigne Martin , Martel‐Pelletier Johanne , Pelletier Jean‐Pierre , Lajeunesse Daniel
Published: April 2009

Objective

Bone tissue in osteoarthritis (OA) is composed of abundant undermineralized osteoid matrix. The aim of this study was to investigate the mechanisms responsible for this abnormal matrix, using in vitro OA subchondral osteoblasts.

Methods

Primary normal and OA osteoblasts were prepared from tibial plateaus. Phenotype was determined by alkaline phosphatase activity, and osteocalcin, osteopontin, prostaglandin E2 (PGE2), and transforming growth factor β1 (TGFβ1) were assessed by enzyme‐linked immunosorbent assay. Expression of COL1A1 and COL1A2 was determined by real‐time polymerase chain reaction. The production of type I collagen was determined by the release of its C‐terminal propeptide and Western blot analysis. In vitro mineralization was evaluated by alizarin red staining. Inhibition of TGFβ1 expression was performed using a small interfering RNA technique.

Results

Mineralization of OA osteoblasts was reduced compared with mineralization of normal osteoblasts, even in the presence of bone morphogenetic protein 2 (BMP‐2). Alkaline phosphatase and osteocalcin levels were elevated in OA osteoblasts compared with normal osteoblasts, whereas osteopontin levels were similar. The COL1A1‐to‐COL1A2 messenger RNA ratio was 3‐fold higher in OA osteoblasts compared with normal osteoblasts, and the production of collagen by OA osteoblasts was increased. Because TGFβ1 inhibits BMP‐2–dependent mineralization, and because TGFβ1 levels are ∼4‐fold higher in OA osteoblasts than in normal osteoblasts, inhibiting TGFβ1 levels in OA osteoblasts corrected the abnormal COL1A1‐to‐COL1A2 ratio and increased alizarin red staining.

Conclusion

Elevated TGFβ1 levels in OA osteoblasts are responsible, in part, for the abnormal ratio of COL1A1 to COL1A2 and for the abnormal production of mature type I collagen. This abnormal COL1A1‐to‐COL1A2 ratio generates a matrix that blunts mineralization in OA osteoblasts.
The sense of smell in systemic lupus erythematosus
Authors: Shoenfeld Netta , Agmon‐Levin Nancy , Flitman‐Katzevman Iveta , Paran Daphna , Katz Bat‐Sheva Porat , Kivity Shaye , Langevitz Pnina , Zandman‐Goddard Gisele , Shoenfeld Yehuda
Published: April 2009

Objective

To assess the olfactory functions in systemic lupus erythematosus (SLE) patients compared with age‐ and sex‐matched healthy controls, and to examine the association between the sense of smell and disease activity and central nervous system (CNS) involvement.

Methods

Olfactory functions in 50 SLE patients and 50 age‐ and sex‐matched controls were evaluated using the Sniffin' Sticks test, the 3 stages of which are threshold, discrimination, and identification (TDI) of different odors. TDI scores were analyzed according to SLE disease activity and CNS involvement.

Results

In both the SLE and control groups, smell deficit correlated with male sex and older age. A decrease in the sense of smell was observed in SLE patients (46%) and controls (25%) (P ≤ 0.02), while loss of smell (anosmia) was documented only in SLE patients (10%). Total TDI scores and individual stages of smell correlated with SLE Disease Activity Index (P < 0.001) and CNS manifestations (P < 0.03).

Conclusion

Our findings suggest that there is a decrease in the sense of smell in SLE patients compared with healthy subjects and that the decrease in the sense of smell among SLE patients correlates with disease activity and CNS involvement.
Improvement of lipid profile is accompanied by atheroprotective alterations in high‐density lipoprotein composition upon tumor necrosis factor blockade: A prospective cohort study in ankylosing spondylitis
Authors: van Eijk I. C. , de Vries M. K. , Levels J. H. M. , Peters M. J. L. , Huizer E. E. , Dijkmans B. A. C. , van der Horst‐Bruinsma I. E. , Hazenberg B. P. C. , van de Stadt R. J. , Wolbink G. J. , Nurmohamed M. T.
Published: April 2009

Objective

Cardiovascular mortality is increased in ankylosing spondylitis (AS), and inflammation plays an important role. Inflammation deteriorates the lipid profile and alters high‐density lipoprotein cholesterol (HDL‐c) composition, reflected by increased concentrations of serum amyloid A (SAA) within the particle. Anti–tumor necrosis factor (anti‐TNF) treatment may improve these parameters. We therefore undertook the present study to investigate the effects of etanercept on lipid profile and HDL composition in AS.

Methods

In 92 AS patients, lipid levels and their association with the inflammation markers C‐reactive protein (CRP), erythrocyte sedimentation rate, and SAA were evaluated serially during 3 months of etanercept treatment. HDL composition and its relationship to inflammation markers was determined in a subgroup of patients, using surface‐enhanced laser desorption/ionization time‐of‐flight analysis.

Results

With anti‐TNF treatment, levels of all parameters of inflammation decreased significantly, whereas total cholesterol, HDL‐c, and apolipoprotein A‐I (Apo A‐I) levels increased significantly. This resulted in a better total cholesterol:HDL‐c ratio (from 3.9 to 3.7) (although the difference was not statistically significant), and an improved Apo B:Apo A‐I ratio, which decreased by 7.5% over time (P = 0.008). In general, increases in levels of all lipid parameters were associated with reductions in inflammatory activity. In addition, SAA was present at high levels within HDL particles from AS patients with increased CRP levels and disappeared during treatment, in parallel with declining plasma levels of SAA.

Conclusion

Our results show for the first time that during anti‐TNF therapy for AS, along with favorable changes in the lipid profile, HDL composition is actually altered whereby SAA disappears from the HDL particle, increasing its atheroprotective ability. These findings demonstrate the importance of understanding the role of functional characteristics of HDL‐c in cardiovascular diseases related to chronic inflammatory conditions.
Evaluation of the diagnostic utility of spinal magnetic resonance imaging in axial spondylarthritis
Authors: Bennett A. N. , Rehman A. , Hensor E. M. A. , Marzo‐Ortega H. , Emery P. , McGonagle D.
Published: April 2009

Objective

Magnetic resonance imaging (MRI) is increasingly used for the diagnosis of axial spondylarthritis (SpA), but it is unknown whether characteristic lesions are actually specific for SpA. This study was undertaken to compare MRI patterns of disease in active SpA, degenerative arthritis (DA), and malignancy.

Methods

Fat‐suppressed MRI of the axial skeleton was performed on 174 patients with back pain and 11 control subjects. Lesions detected by MRI, including Romanus lesions (RLs) and end‐plate, diffuse vertebral body, posterior element, and spinous process bone marrow edema (BME) lesions, were scored in a blinded manner. An imaging diagnosis was given based on MRI findings alone, and this was compared with the gold‐standard treating physician's diagnosis.

Results

The physician diagnosis was SpA in 64 subjects, DA in 45 subjects, malignancy in 45 subjects, other diagnoses in 20 subjects, and normal in 11 subjects. There was 72% agreement between the imaging diagnosis and physician diagnosis. End‐plate edema, degenerative discs, and RLs were frequently observed in patients with any of the 3 major diagnoses. Single RLs were of low diagnostic utility for SpA, but ≥3 RLs (likelihood ratio [LR] 12.4) and severe RLs (LR infinite) in younger subjects were highly diagnostic of SpA. Posterior element BME lesions of mild or moderate grade were also highly diagnostic of SpA (LR 14.5). The most common diagnostic confusion was between SpA and DA, since both had RLs present and the presence/absence of degenerative discs did not change the diagnostic assessment.

Conclusion

This study confirms the high diagnostic utility of MRI in axial SpA, with severe or multiple RLs evident on MRI being characteristic in younger patients and mild/moderate posterior element lesions being specific for SpA. However, MRI lesions previously considered to be characteristic of SpA could also be found frequently in patients with DA and patients with malignancy, and therefore such lesions should be interpreted with caution, particularly in older patients.
Confirmation of STAT4, IL2/IL21, and CTLA4 polymorphisms in rheumatoid arthritis
Authors: Daha Nina A. , Kurreeman Fina A. S. , Marques Rute B. , Stoeken‐Rijsbergen Gerrie , Verduijn Willem , Huizinga Tom W. J. , Toes René E. M.
Published: April 2009

Objective

Recent advances have led to novel identification of genetic polymorphisms that are associated with susceptibility to rheumatoid arthritis (RA). Currently, 5 loci (HLA, PTPN22, TRAF1/C5, TNFAIP3, and STAT4) have been consistently reported, whereas others have been observed less systematically. The aim of the present study was to independently replicate 3 recently described RA susceptibility loci, STAT4, IL2/IL21, and CTLA4, in a large Dutch case–control cohort, and to perform a meta‐analysis of all published studies to date and investigate the relevance of the findings in clinically well‐defined subgroups of RA patients with or without autoantibodies.

Methods

The STAT4, IL2/IL21, and CTLA4 gene polymorphisms (rs7574865, rs6822844, and rs3087243, respectively) were genotyped in 877 RA patients and 866 healthy individuals. A meta‐analysis of all published studies of disease association with these polymorphisms was performed using the Mantel‐Haenszel fixed‐effects method.

Results

An association of STAT4, IL2/IL21, and CTLA4 with RA was detected in Dutch patients (odds ratio [OR] 1.19 [P = 0.031], OR 0.84 [P = 0.051], and OR 0.87 [P = 0.041], respectively). Results from the meta‐analysis confirmed an association of all 3 polymorphisms with RA in Caucasians (OR 1.24 [P = 1.66 × 10−11], OR 0.78 [P = 5.6 × 10−5], and OR 0.91 [P = 1.8 × 10−3], respectively). The meta‐analysis also revealed that STAT4 predisposed to disease development equally in patients with autoantibodies and those without autoantibodies, and that CTLA4 enhanced the development of anti–citrullinated protein antibody (ACPA)–positive RA as compared with ACPA‐negative RA.

Conclusion

Our results replicate and firmly establish the association of STAT4 and CTLA4 with RA and provide highly suggestive evidence for IL2/IL21 loci as a risk factor for RA. Given the strong statistical power of our meta‐analysis to confirm a true‐positive association, these findings provide considerable support for the involvement of CTLA4 in distinct subsets of RA patients.
Hip flexion range of motion and physical function in hip osteoarthritis: Mediating effects of hip extensor strength and pain
Authors: Pua Yong‐Hao , Wrigley Tim V. , Cowan Sallie M. , Bennell Kim L.
Published: April 2009

Objective

Hip flexion range of motion (ROM), hip extensor strength (torque production), and hip pain are important correlates of physical function in individuals with hip osteoarthritis (OA). However, the relationships among these variables remain unclear. The purpose of this study was to examine whether hip extensor strength and hip pain mediate the association between hip flexion ROM and physical function.

Methods

Participants were 100 adults (mean age 62 years) with radiographically confirmed hip OA. Passive hip flexion ROM was measured using a digital inclinometer, and isometric hip extensor strength was measured using a force transducer. Self‐report measures of physical function and pain were assessed by the Short Form 36 (SF‐36) questionnaire, and physical performance was assessed by the gait speed, step test, and stair climb test.

Results

Multiple mediation analyses, adjusted for demographic and anthropometric measures, revealed that the association between hip flexion ROM and SF‐36 physical function scores was fully mediated by SF‐36 bodily pain scores and hip extensor strength. Hip extensor strength mediated the hip flexion effects on gait speed and step test performance, while the SF‐36 bodily pain scores mediated the hip flexion stair performance association.

Conclusion

In individuals with symptomatic hip OA, hip pain and hip extensor strength mediated the influence of hip flexion ROM on physical function. These results suggest that interventions to improve the range of hip motion may be clinically indicated.
Patient‐reported outcomes following biologic therapy in a sample of adults with rheumatoid arthritis recruited from community‐based rheumatologists
Authors: Katz Patricia , Yelin Edward , Patel Vaishali , Huang Xing‐Yue , Chiou Chiun‐Fang
Published: April 2009

Objective

To examine self‐reported symptoms and functioning in a community‐based sample of persons with rheumatoid arthritis who did and did not initiate treatment with biologic agents.

Methods

Data were from annual telephone interviews (1998–2003) with an observational cohort identified through community rheumatologists. Self‐reported function and symptoms of subjects who initiated biologic therapy (etanercept or infliximab) and reported consistent use at 2 annual interviews (continuous use; n = 64) were compared at 1 year prior to initiation of therapy (baseline), and years 1 and 2 of therapy to those with no biologic therapy (n = 183) and those who initiated biologic therapy but discontinued use (n = 42).

Results

At baseline, subjects taking biologic agents reported significantly worse function and symptoms on all measures except fatigue and pain severity. After 2 years, significant differences in the Health Assessment Questionnaire scores remained, but there were no other significant differences between the nonuser group and the continuous use group. The discontinued use group exhibited significantly greater pain severity and more painful joints than nonusers. Improvements in the number of painful (33.4% versus 16.2%; P = 0.004), and swollen (38.4% versus 18.7%; P = 0.003) joints, and morning stiffness (27.3% versus 10.4%; P = 0.001) were more frequent in the continuous use group than in the nonuser group.

Conclusion

Results suggest that biologic treatment was initiated based on severe disease. Over ∼17 months of treatment, differences in some but not all symptoms between the continuous use group and the nonuser group narrowed to statistical nonsignificance.
Some new results involving general standby systems
Authors: Li Xiaohu , Zhang Zhengcheng , Wu Yudan
Published: April 2009

This article presents a stochastic comparison on the total lifetime of the general standby system and a discussion of the optimal allocation of a general standby component in a series system with two independent components. Several examples are also presented to justify the main results, which provide nice generalizations of some existing conclusions in the literature. Copyright © 2009 John Wiley & Sons, Ltd.
Maximum likelihood estimators of clock offset and skew under exponential delays
Authors: Li Jun , Jeske Daniel R.
Published: April 2009

Accurate clock synchronization is essential for many data network applications. Various algorithms for synchronizing clocks rely on estimators of the offset and skew parameters that describe the relation between times measured by two different clocks. Maximum likelihood estimation (MLE) of these parameters has previously been considered under the assumption of exponentially distributed network delays with known means. We derive the MLEs under the more common case of exponentially distributed network delays with unknown means and compare their mean‐squared error properties to a recently proposed alternative estimator. We investigate the robustness of the derived MLE to the assumption of non‐exponential network delays, and demonstrate the effectiveness of a bootstrap bias‐correction technique. Copyright © 2009 John Wiley & Sons, Ltd.
Exposure to inhomogeneous static magnetic field ceases mechanical allodynia in neuropathic pain in mice
Authors: Antal Miklós , László János
Published: April 2009

Magnetic therapy as a self‐care intervention has led to the conduct of numerous human trials and animal experiments. Results concerning the analgesic efficacy of magnetic exposure, however, are inconsistent. By using a magnetic device generating an inhomogeneous static magnetic field (iSMF), here we studied how the whole‐body exposure to iSMF may influence the mechanical withdrawal threshold (MWT) of the hind paw in different stages of neuropathic pain evoked by partial ligation of the sciatic nerve in mice. It was found that iSMF exposure did not prevent the decrease of MWT in the first postoperative week. A 2‐week long iSMF treatment that was started just after the nerve ligation elevated MWT values to a modest extent. However, the effectiveness of a daily exposure to iSMF was much more prominent when it was applied between postoperative days 15 and 28. In this case, MWT was already noticeably increased after the first treatment and it practically reached the control values by the end of the 2‐week long exposure period. The results suggest that exposure to iSMF cannot prevent the development of mechanical allodynia, but can inhibit processes that maintain the increased sensitivity to mechanical stimuli in neuropathic pain. Bioelectromagnetics 30:438–445, 2009. © 2009 Wiley‐Liss, Inc.