Fiona Salway

In adult onset myositis, the presence of interstitial lung disease and myositis specific/associated antibodies are governed by HLA class II haplotype, rather than by myositis subtype.

The aim of this study was to investigate HLA class II associations in polymyositis (PM) and dermatomyositis (DM), and to determine how these associations influence clinical and serological differences. DNA samples were obtained from 225 UK Caucasian idiopathic inflammatory myopathy patients (PM = 117, DM = 108) and compared with 537 randomly selected UK Caucasian controls. All cases had also been assessed for the presence of related malignancy and interstitial lung disease (ILD), and a number of myositis-specific/myositis-associated antibodies (MSAs/MAAs). Subjects were genotyped for HLA-DRB1, DQA1 and DQB1. HLA-DRB1*03, DQA1*05 and DQB1*02 were associated with an increased risk for both PM and DM. The HLA-DRB1*03-DQA1*05-DQB1*02 haplotype demonstrated strong association with ILD, irrespective of myositis subtype or presence of anti-aminoacyl-transfer RNA synthetase antibodies. The HLA-DRB1*07-DQA1*02-DQB1*02 haplotype was associated with risk for anti-Mi-2 antibodies, and discriminated PM from DM (odds ratio 0.3, 95% confidence interval 0.1–0.6), even in anti-Mi-2 negative patients. Other MSA/MAAs showed specific associations with other HLA class II haplotypes, irrespective of myositis subtype. There were no genotype, haplotype or serological associations with malignancy. The HLA-DRB1*03-DQA1*05-DQB1*02 haplotype associations appear to not only govern disease susceptibility in Caucasian PM/DM patients, but also phenotypic features common to PM/DM. Though strongly associated with anti-Mi-2 antibodies, the HLA-DRB1*07-DQA1*02-DQB1*02 haplotype shows differential associations with PM/DM disease susceptibility. In conclusion, these findings support the notion that myositis patients with differing myositis serology have different immunogenetic profiles, and that these profiles may define specific myositis subtypes.

Identification of new reference genes for the normalisation of canine osteoarthritic joint tissue transcripts from microarray data.

BackgroundReal-time reverse transcriptase quantitative polymerase chain reaction (real-time RT-qPCR) is the most accurate measure of gene expression in biological systems. The comparison of different samples requires the transformation of data through a process called normalisation. Reference or housekeeping genes are candidate genes which are selected on the basis of constitutive expression across samples, and allow the quantification of changes in gene expression. At present, no reference gene has been identified for any organism which is universally optimal for use across different tissue types or disease situations. We used microarray data to identify new reference genes generated from total RNA isolated from normal and osteoarthritic canine articular tissues (bone, ligament, cartilage, synovium and fat). RT-qPCR assays were designed and applied to each different articular tissue. Reference gene expression stability and ranking was compared using three different mathematical algorithms.ResultsTwelve new potential reference genes were identified from microarray data. One gene (mitochondrial ribosomal protein S7 [MRPS7]) was stably expressed in all five of the articular tissues evaluated. One gene HIRA interacting protein 5 isoform 2 [HIRP5]) was stably expressed in four of the tissues evaluated. A commonly used reference gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was not stably expressed in any of the tissues evaluated. Most consistent agreement between rank ordering of reference genes was observed between Bestkeeper© and geNorm, although each method tended to agree on the identity of the most stably expressed genes and the least stably expressed genes for each tissue. New reference genes identified using microarray data normalised in a conventional manner were more stable than those identified by microarray data normalised by using a real-time RT-qPCR methodology.ConclusionMicroarray data normalised by a conventional manner can be filtered using a simple stepwise procedure to identify new reference genes, some of which will demonstrate good measures of stability. Mitochondrial ribosomal protein S7 is a new reference gene worthy of investigation in other canine tissues and diseases. Different methods of reference gene stability assessment will generally agree on the most and least stably expressed genes, when co-regulation is not present.

Molecular phenotypic descriptors of Dupuytren's disease defined using informatics analysis of the transcriptome.

PURPOSE Dupuytrens disease (DD) is a fibroproliferative disorder of unknown etiopathogenesis, which may cause progressive, permanent contracture of digits. Previous studies provide compelling evidence that genetic alterations play an important role. Macroscopically affected areas demonstrate phenotypic differences between the two structurally distinct fibrotic elements in DD (ie, the nodule and the cord). In this study, we set out to (1) compare gene expression profiles between DD and transverse carpal fascia of control subjects (external control); (2) profile DD cords and nodules from the palm against the unaffected transverse palmar fascia (internal control); and (3) identify biologically important candidate genes from the transcriptome profiles. METHODS RNA samples from DD nodules (n = 4), cords (n = 4), and internal control (n = 4) as well as external control (n = 4) from unaffected individuals were subjected to differential gene expression profile analysis. Changes of more than 2-fold in DD groups and controls were recorded. Quantitative reverse transcriptase-polymerase chain reactions were performed to validate 16 implicated genes, which included developmental control genes, matrix metalloproteinases, and apoptotic genes. RESULTS Several genes associated with DD formation were common across all 6 pairwise analyses. Genes markedly upregulated shared common expression levels across all pairwise analysis studies. Pairs involving the DD nodule arrays were notably distinguishable from all other permutations. The majority of genes dysregulated in the DD cords demonstrated an increase in fold change when compared with the DD nodule tissues. Key collagens, collagenases, metalloproteinases, and inhibitors were identified. Genes involved in cytoskeleton development and lipid metabolism were markedly dysregulated. Confirmations of these alterations were obtained in quantitative reverse transcriptase-polymerase chain reaction. CONCLUSIONS These data demonstrate a gradation in expression of certain genes in DD tissue phenotypes compared with control fascia. Transcriptome profiling is predictive not only of disease but also of disease phenotype. These results indicate a number of important candidate genes associated with DD formation, which may provide clues for molecular mechanisms involved in DD pathogenesis.

Expression stability of commonly used reference genes in canine articular connective tissues.

BackgroundThe quantification of gene expression in tissue samples requires the use of reference genes to normalise transcript numbers between different samples. Reference gene stability may vary between different tissues, and between the same tissue in different disease states. We evaluated the stability of 9 reference genes commonly used in human gene expression studies. Real-time reverse transcription PCR and a mathematical algorithm were used to establish which reference genes were most stably expressed in normal and diseased canine articular tissues and two canine cell lines stimulated with lipolysaccaride (LPS).ResultsThe optimal reference genes for comparing gene expression data between normal and diseased infrapatella fat pad were RPL13A and YWHAZ (M = 0.56). The ideal reference genes for comparing normal and osteoarthritic (OA) cartilage were RPL13A and SDHA (M = 0.57). The best reference genes for comparing normal and ruptured canine cranial cruciate ligament were B2M and TBP (M = 0.59). The best reference genes for normalising gene expression data from normal and LPS stimulated cell lines were SDHA and YWHAZ (K6) or SDHA and HMBS (DH82), which had expression stability (M) values of 0.05 (K6) and 0.07 (DH82) respectively. The number of reference genes required to reduce pairwise variation (V) to <0.20 was 4 for cell lines, 5 for cartilage, 7 for cranial cruciate ligament and 8 for fat tissue. Reference gene stability was not related to the level of gene expression.ConclusionThe reference genes demonstrating the most stable expression within each different canine articular tissue were identified, but no single reference gene was identified as having stable expression in all different tissue types. This study underlines the necessity to select reference genes on the basis of tissue and disease specific expression profile evaluation and highlights the requirement for the identification of new reference genes with greater expression stability for use in canine articular tissue gene expression studies.

ALK1 signalling analysis identifies angiogenesis related genes and reveals disparity between TGF-β and constitutively active receptor induced gene expression

BackgroundTGF-β1 is an important angiogenic factor involved in the different aspects of angiogenesis and vessel maintenance. TGF-β signalling is mediated by the TβRII/ALK5 receptor complex activating the Smad2/Smad3 pathway. In endothelial cells TGF-β utilizes a second type I receptor, ALK1, activating the Smad1/Smad5 pathway. Consequently, a perturbance of ALK1, ALK5 or TβRII activity leads to vascular defects. Mutations in ALK1 cause the vascular disorder hereditary hemorrhagic telangiectasia (HHT).MethodsThe identification of ALK1 and not ALK5 regulated genes in endothelial cells, might help to better understand the development of HHT. Therefore, the human microvascular endothelial cell line HMEC-1 was infected with a recombinant constitutively active ALK1 adenovirus, and gene expression was studied by using gene arrays and quantitative real-time PCR analysis.ResultsAfter 24 hours, 34 genes were identified to be up-regulated by ALK1 signalling. Analysing ALK1 regulated gene expression after 4 hours revealed 13 genes to be up- and 2 to be down-regulated. Several of these genes, including IL-8, ET-1, ID1, HPTPη and TEAD4 are reported to be involved in angiogenesis. Evaluation of ALK1 regulated gene expression in different human endothelial cell types was not in complete agreement. Further on, disparity between constitutively active ALK1 and TGF-β1 induced gene expression in HMEC-1 cells and primary HUVECs was observed.ConclusionGene array analysis identified 49 genes to be regulated by ALK1 signalling and at least 14 genes are reported to be involved in angiogenesis. There was substantial agreement between the gene array and quantitative real-time PCR data. The angiogenesis related genes might be potential HHT modifier genes. In addition, the results suggest endothelial cell type specific ALK1 and TGF-β signalling.

Interferon-gamma and interleukin-4 gene polymorphisms in Caucasian idiopathic inflammatory myopathy patients in UK

Objective: To determine whether interferon-gamma (IFN-γ) and interleukin-4 (IL-4) genes confer susceptibility for the idiopathic inflammatory myopathies (IIMs). Methods: A large cross-sectional study of UK caucasian adults with polymyositis (PM, n = 101), dermatomyositis (DM, n = 94) and myositis overlapping with a connective tissue disease (myositis/CTD-overlap, n = 70) was completed. 177 ethnically matched controls were available for comparison. Single-nucleotide polymorphisms (SNPs) within intronic regions coding for IL-4, IFN-γ and a microsatellite marker within intron 1 of the IFN-γ gene were typed. Results: Strong linkage disequilibrium was present between SNPs in each gene. In the IFN-γ gene, a weak allelic association was observed in PM versus controls at rs1861493 (odds ratio (OR) 1.6, 95% confidence interval (CI) 1.03 to 2.4). The microsatellite IFN-γ CA(14) allele was associated with risk for IIMs overall (OR 3.3, 95% CI 1.4 to 7.8), the strongest association being observed within the anti-U1-ribonucleoprotein (RNP) group (OR 6.0, 95% CI 1.5 to 23.1), and persisting after adjustment for known myositis human leucocyte antigen (HLA) class II associations. Conclusions: Genetic markers in the IFN-γ gene demonstrate significant allelic associations with the IIMs in a UK Caucasian population. The SNPs tested in this study within the region coding for IL-4 fail to show significant associations with susceptibility to IIM disease.

Potential risk factors associated with the use of cidofovir to treat benign human papillomavirus-related disease.

BACKGROUND Cidofovir is currently being used off-licence to treat different viral infections, such as benign low-risk human papillomavirus (HPV)-related recurrent respiratory papillomatosis (RRP). There are concerns over the safety of this practice as rat studies demonstrated a high malignant transformation rate. As yet, there are no clinical reports of cidofovir-induced malignant changes in humans. METHODS Telomerase immortalised human keratinocytes (hTert) stably expressing E6 proteins from either low-risk HPV6b or high-risk HPV16 and vector control cells were treated with either low-dose (5 microg/ml) or higher dose (30 microg/ml) cidofovir for 2 days and the effects evaluated by clonogenic survival assays. Based on these results, gene expression microarray analysis was performed on cidofovir-treated low-risk E6 and vector cells before, during and after drug treatment, and the results verified by real-time PCR. RESULTS Both low-risk and high-risk E6-expressing cells show significantly improved long-term survival compared with vector control cells when exposed to 5 microg/ml cidofovir for 2 days, (hTert T6E6 P=0.0007, hTert T16E6 P=0.00023 and hTert vector control P=0.62). Microarray and real-time PCR analyses of low-dose cidofovir-treated low-risk E6-expressing cells revealed changes in gene expression that are known to be associated with malignant progression, which were not observed in drug-treated vector control cells. CONCLUSIONS This is the first report that cidofovir can both increase cell survival and induce alterations in gene expression that are known to be associated with malignant transformation in cells transduced only with the E6 gene from low-risk HPV. It is our belief that these data provide cause for concern over the off-license use of this drug to treat RRP.

Clinical, serological and HLA profiles in non-Caucasian UK idiopathic inflammatory myopathy.

Clinical, serological and HLA profiles in non-Caucasian UK idiopathic inflammatory myopathy SIR, Since 2000, the UK Adult Onset Myositis Immunogenetic Collaboration (AOMIC) has recruited idiopathic inflammatory myopathy (IIM) cases across the UK. In this brief report, we summarize the clinical, serological and HLA Class II status of non-Caucasian IIM cases, to ascertain whether differences are observed among UK IIM ethnic populations. DNA was available from 28 UK non-Caucasian IIM cases. Adult IIM patients, aged 518 years of age at disease onset, with probable or definite myositis [1] were recruited through AOMIC [2]. Data were also available from 303 UK Caucasian IIM cases previously described [2, 3]. The collaborating AOMIC physicians confirmed interstitial lung disease (ILD) and cancer-associated myositis (CAM) [4] by relevant investigations. Radio-immunoprecipitation was used for determination of myositis-specific antibodies (anti-previously described [2, 4]. This study was approved by the local research ethics committee and informed consent was obtained according to the Declaration of Helsinki. A Wilcoxon–Mann– Whitney test was used to compare the age of onset between Caucasians and non-Caucasians. Associations were calculated from 2 Â 2 contingency tables using the chi-squared test. Of the 28 non-Caucasian IIM cases, 14 were Asian, 12 African/ Afro-Caribbean and 2 of mixed-race origin (Table 1). Sixty-four percent of the non-Caucasian IIM cases were females, compared with 71% female Caucasian cases (P ¼ 0.46). The median age of onset of the non-Caucasian cohort was significantly lower than that of the Caucasian cohort [non-Caucasians, 37 years (inter-After stratification by gender, this observation was only significantly lower in non-Caucasian females [non-Caucasians females, 33 years (27, 41) vs Caucasian females, 49 years (38, 60), P ¼ 0.0001]. No significant difference for age of onset was noted between African/Afro-Caribbean or Asian cases. CAM was not detected in the non-Caucasian cohort, but was present in 6% of the Caucasian IIM cohort, and in 15% of the DM cases [4]. With respect to ILD, there were eight (29%) non-Caucasian IIM cases and six of seven (86%) anti-synthetase antibody-positive cases. Although a higher frequency of ILD was observed in African/Afro-Caribbean (35%) compared with Asian (18%) cases, due to the small sample size this was not statistically significant (P ¼ 0.24). This difference was not attributable to differences in anti-synthetase antibody frequency. In comparison, the overall frequency of ILD in the Caucasian cohort was 20%, and 44% in anti-synthetase positive cases. Within the non-Caucasian cohort, only PM cases possessed anti-Jo-1 …