Circulating miRNAs in hand osteoarthritis.

OBJECTIVE: Hand osteoarthritis (OA) is a frequent musculoskeletal disorder with an increasing prevalence during ageing. This study aimed to evaluate circulating microRNAs (miRNAs) in the plasma of patients with hand OA compared with age- and sex-matched healthy control subjects. METHODS: In total, 238 participants (96 with erosive and 73 with non-erosive hand OA patients and 69 healthy control subjects) were included in this study. All patients underwent clinical examinations, including self-reported measures (AUSCAN and Algofunctional index). Radiographs of both hands were scored with the Kallman scale. The profile of miRNAs in plasma was screened using TaqMan™ Low-Density Array, and candidate miRNAs were validated on two quantitative real-time PCR (qRT-PCR) systems (QuantStudio and SmartChip). RESULTS: Of all the 754 miRNAs, 40 miRNAs were different between hand OA patients and healthy control subjects in the screening cohort. Following the two-phase validation process, three miRNAs (miR-23a-3p, miR-146a-5p, and miR-652-3p) were increased in patients with hand OA compared with healthy control subjects and were associated with the AUSCAN sum score and AUSCAN pain. Furthermore, an inverse correlation of miR-222-3p with the Kallman radiographic score was found. The expression of miRNAs did not differ between erosive and non-erosive hand OA. CONCLUSION: The profile of circulating miRNAs could unveil candidate biomarkers associated with hand OA symptoms. Longitudinal studies are required to determine the role of miRNAs in hand OA.

Amylolytic enzymes: molecular aspects of their properties.

The present review describes the structural features of alpha-amylase, beta-amylase and glucoamylase that are the best known amylolytic enzymes. Although they show similar function, i.e. catalysis of hydrolysis of alpha-glucosidic bonds in starch and related saccharides, they are quite different. alpha-Amylase is the alpha --> alpha retaining glycosidase (it uses the retaining mechanism), and beta-amylase together with glucoamylase are the alpha --> beta inverting glycosidases (they use the inverting mechanism). While beta-amylase and glucoamylase form their own families 14 and 15, respectively, in the sequence-based classification of glycoside hydrolases, alpha-amylase belongs to a large clan of three families 13, 70 and 77 consisting of almost 30 different specificities. Structurally both alpha-amylase and beta-amylase rank among the parallel (beta/alpha)8-barrel enzymes, glucoamylase adopts the helical (alpha/alpha)6-barrel fold. The catalytic (beta/alpha)8-barrels of alpha-amylase and beta-amylase differ from each other. The only common sequence-structural feature is the presence of the starch-binding domain responsible for the binding and ability to digest raw starch. It is, however, present in about 10% of amylases and behaves as an independent evolutionary module. A brief discussion on structure-function and structure-stability relationships of alpha-amylases and related enzymes is also provided.