To identify susceptibility loci for ankylosing spondylitis, we performed a two-stage genome-wide association study in Han Chinese. In the discovery stage, we analyzed 1,356,350 autosomal SNPs in 1,837 individuals with ankylosing spondylitis and 4,231 controls; in the validation stage, we analyzed 30 suggestive SNPs in an additional 2,100 affected individuals and 3,496 controls. We identified two new susceptibility loci between EDIL3 and HAPLN1 at 5q14.3 (rs4552569; P = 8.77 × 10(-10)) and within ANO6 at 12q12 (rs17095830; P = 1.63 × 10(-8)). We also confirmed previously reported associations in Europeans within the major histocompatibility complex (MHC) region (top SNP, rs13202464; P < 5 × 10(-324)) and at 2p15 (rs10865331; P = 1.98 × 10(-8)). We show that rs13202464 within the MHC region mainly represents the risk effect of HLA-B*27 variants (including HLA-B*2704, HLA-B*2705 and HLA-B*2715) in Chinese. The two newly discovered loci implicate genes related to bone formation and cartilage development, suggesting their potential involvement in the etiology of ankylosing spondylitis.

MicroRNAs (miRNAs) play a key role in the regulation of almost all the physiological and pathological processes, including bone metabolism. Recent studies have suggested that miR-27 might play a key role in osteoblast differentiation and bone formation. Increasing evidence indicates that the canonical Wnt signaling pathway contributes to different stages of bone formation. In this study, we identify miR-27a can promote osteoblast differentiation by repressing a new target, secreted frizzled-related proteins 1 (sFRP1) expression at the transcriptional level. Here, 21 candidate targets of miR-27a involved in canonical Wnt/β-catenin signaling were predicted, and a significant decrease in sFRP1 luciferase activity was observed both in 293T and MG63 cells co-transfected with the matched luciferase reporter constructs and miR-27a mimic. Furthermore, the presence of exogenous miR-27a significantly decreased sFRP1 mRNA and protein expression in hFOB1.19 cells during both proliferation and osteogenic differentiation. The over-expression of miR-27a or knockdown sFRP1 significantly increased the percentage of apoptotic hFOBs, the percentage of cells in the G2-M phase of the cell cycle and the expression of key osteoblastic markers, including ALP, SPP1, RUNX2 and ALP activity. Over-expression of miR-27a or knockdown of endogenous sFRP1 led to an accumulation of β-catenin in hFOBs. In the present study, we demonstrate that miR-27a induced gene silencing effect is a vital mechanism contributing to bone metabolism in hFOB cells in vitro, which is partly affected by the post-transcriptional regulation of sFRP1, during osteoblast proliferation, apoptosis and differentiation.

Objective Gout is the most common inflammatory arthritis and the worldwide incidence is increasing. By revealing the metabolic alterations in serum and urine of gout patients, the first aim of our study was to discover novel molecular biomarkers allowing for early diagnosis. We also aimed to investigate the underlying pathogenic pathways. Methods Serum and urine samples from gout patients (n = 30) and age-matched healthy controls (n = 30) were analysed by ultra-performance liquid chromatography–mass spectrometry (UPLC-MS) to screen the differential metabolites and construct a diagnostic model. Next, the model was verified and optimized in the second validation cohort (n = 100). The pathways were illustrated to understand the underlying pathogenesis of gout. Results In general, serum metabolomics demonstrated a clearer distinction than urine metabolomics. In the discovery cohort, 40 differential serum metabolites were identified that could distinguish gout patients from healthy controls. Among them, eight serum metabolites were verified in the validation cohort. Through regression analysis, the final model consisted of three serum metabolites—pyroglutamic acid, 2-methylbutyryl carnitine and Phe-Phe—that presented optimal diagnostic power. The three proposed metabolites produced an area under the curve of 0.956 (95% CI 0.911, 1.000). Additionally, the proposed metabolic pathways were primarily involved in purine metabolism, branched-chain amino acids (BCAAs) metabolism, the tricarboxylic acid cycle, synthesis and degradation of ketone bodies, bile secretion and arachidonic acid metabolism. Conclusion The metabolomics signatures could serve as an efficient tool for early diagnosis and provide novel insights into the pathogenesis of gout.

Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) is a standard instrument regularly used to assess disease activity of patients with ankylosing spondylitis (AS). However, the well-being of a patient is also affected by impairment of function as well as psychological status and other factors. The objective of this study was to evaluate if psychological status, stressful life events, and sleep quality contribute significantly to BASDAI. Six hundred eighty-three AS patients satisfying the Modified New York Criteria for AS were recruited from the rheumatology clinics of seven hospitals in China. Patients with other concomitant disorders were excluded. Participants were requested to complete a set of clinical examinations and the following questionnaires: Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), Zung Self-Rating Anxiety Scale (SAS), Zung Self-Rating Depression Scale (SDS), Pittsburgh Sleep Quality Index Questionnaire (PSQI), Health Assessment Questionnaire for Spondyloarthropathies (HAQ-S), and Social Readjustment Rating Scale (SRRS). Spearman correlation analysis showed that BASDAI was highly associated with degree and duration of morning stiffness, overall pain, nocturnal back pain, overall back pain, anxiety, and BASFI (all P < 0.001), but were not associated with education, HAQ-S, and sleep medication in PSQI (P > 0.05). Multiple stepwise regression analysis indicated that overall pain was the maximal statistical contribution in predicting disease activity (standardized coefficient, 0.335). In hierarchic multiple regression analysis, psychological variables added an only additional 2.7% to the overall R(2) beyond that accounted for by demographic and medical variables, resulting in a final R(2) of 53.5%. Although BASDAI is a very good measurement of pain and stiffness and to a certain extent effect of functional impairment in AS, it barely takes into account psychological status, stress life events, and sleep quality These factors should be evaluated by other modalities.

Our study found that adalimumab was highly effective in reducing inflammation in active AS patients, but it was accompanied by the formation of FDL in the lumbar spine and decrease in serum DKK-1 levels.