IntroductionIncreased expression of aggrecanase-1 (ADAMTS-4) has emerged as an important factor in osteoarthritis (OA) and other joint diseases. This study aimed to determine whether the expression of ADAMTS-4 in human chondrocytes is regulated by miRNA.MethodsMiRNA targets were identified using bioinformatics. Chondrocytes were isolated from knee cartilage and treated with interleukin-1 beta (IL-1β). Gene expression was quantified using TaqMan assays and protein production was determined by immunoblotting. Luciferase reporter assay was used to verify interaction between miRNA and target messenger RNA (mRNA).ResultsIn silico analysis predicted putative target sequence of miR-125b on ADAMTS-4. MiR-125b was expressed in both normal and OA chondrocytes, with significantly lower expression in OA chondrocytes than in normal chondrocytes. Furthermore, IL-1β-induced upregulation of ADAMTS-4 was suppressed by overexpression of miR-125b in human OA chondrocytes. In the luciferase reporter assay, mutation of the putative miR-125b binding site in the ADAMTS-4 3'UTR abrogated the suppressive effect of miR125.ConclusionsOur results indicate that miR-125b plays an important role in regulating the expression of ADAMTS-4 in human chondrocytes and this identifies miR-125b as a novel therapeutic target in OA.

A porcine bacterial artificial chromosome (BAC) library consisting of 103,488 clones has been constructed. The average insert size in the BAC vector was calculated to be 133 kb based on the examination of 189 randomly selected clones, indicating that the library contained 4.4 genome equivalents. The library can be screened by two-step PCR. The first screening step is performed on 22 superpools, each containing 4704 clones (49 x 96 well plates). In the second screening step, 49 plates comprising a superpool are arrayed in a 7 x 7 matrix and 4D-PCR is performed. Screening of the library superpools by PCR for 125 marker sequences selected from different regions of swine genome revealed 123 sequences, indicating that the library is not biased. Subsequent screenings (4D-PCR) were successfully applied for identification of clones containing each marker sequence. This porcine BAC library and the PCR screening system are useful for isolation of genomic DNA fragments containing desired sequences.

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The development of informative polymorphic markers is essential for QTL mapping. We developed 50 microsatellite markers from BAC clones containing genes that were predicted to map swine chromosome 4 (SSC4) according to comparative analysis between human and swine chromosomes, and constructed a linkage map that consisted of 37 markers including 24 markers closely linked to genes in BAC clones. Microsatellite markers were developed by direct-sequencing of BAC clones and our results demonstrated that this method was effective for developing microsatellite markers in specific regions on chromosomes. Effective development of microsatellite markers closely linked to genes can further accelerate the comparative studies of chromosomes between different species.

Reverse or bidirectional Zoo-FISH suggests that synteny between porcine chromosome 12 (SSC12) and human chromosome 17 (HSA17) is completely conserved. The construction of a high-resolution radiation hybrid (RH) map for SSC12 provides a unique opportunity to determine whether chromosomal synteny is reflected at the molecular level by comparative gene mapping of SSC12 and HSA17. We report an initial, high-resolution RH map of SSC12 on the 12,000-rad IMNpRH2 panel using CarthaGene software. This map contains a total of 320 markers, including 20 microsatellites and 300 ESTs/genes, covering approximately 4836.9 cR12,000. The markers were ordered in 16 linkage groups at LOD 6.0 using framework markers previously mapped on the IMpRH7000-rad SSC12 and porcine genetic maps. Ten linkage groups ordered more than 10 markers, with the largest containing 101 STSs. The resolution of the current RH map is approximately 15.3 kb/cR on SSC12, a significant improvement over the second-generation EST SSC12 RH7000-rad map of 103 ESTs and 15 framework markers covering approximately 2287.2 cR7000. Compared to HSA17, six distinct segments were identified, revealing macro-rearrangements within the apparently complete synteny between SSC12 and HSA17. Further analysis of the order of 245 genes (ESTs) on HSA17 and SSC12 also revealed several micro-rearrangements within a synteny segment. A high-resolution SSC12 RH12,000-rad map will be useful in fine-mapping QTL and as a scaffold for sequencing this chromosome.

Abnormal activation of the Wnt/β-catenin signaling is implicated in the osteoarthritis (OA) pathology. We searched for a pre-approved drug that suppresses abnormally activated Wnt/β-catenin signaling and has a potency to reduce joint pathology in OA. We introduced the TOPFlash reporter plasmid into HCS-2/8 human chondrosarcoma cells to estimate the Wnt/β-catenin activity in the presence of 10 μM each compound in a panel of pre-approved drugs. We found that fluoxetine, an antidepressant in the class of selective serotonin reuptake inhibitors (SSRI), down-regulated Wnt/β-catenin signaling in human chondrosarcoma cells. Fluoxetine inhibited both Wnt3A- and LiCl-induced loss of proteoglycans in chondrogenically differentiated ATDC5 cells. Fluoxetine increased expression of Sox9 (the chondrogenic master regulator), and decreased expressions of Axin2 (a marker for Wnt/β-catenin signaling) and Mmp13 (matrix metalloproteinase 13). Fluoxetine suppressed a LiCl-induced increase of total β-catenin and a LiCl-induced decrease of phosphorylated β-catenin in a dose-dependent manner. An in vitro protein-binding assay showed that fluoxetine enhanced binding of β-catenin with Axin1, which is a scaffold protein forming the degradation complex for β-catenin. Fluoxetine suppressed LiCl-induced β-catenin accumulation in human OA chondrocytes. Intraarticular injection of fluoxetine in a rat OA model ameliorated OA progression and suppressed β-catenin accumulation.

PurposePatients who undergo total knee arthroplasty (TKA) or total hip arthroplasty (THA) often develop postoperative pain. Exercise approaches are recommended postoperatively; however, the impact of excessive variation in physical activity is unclear. The purpose of the present preliminary study was to investigate the impact of excessive variation in physical activity using the accelerometer in the early period after TKA or THA.Patients and methodsSeventy-two patients were enrolled in the study. Forty patients underwent initial TKA, and 32 initial THA. Physical activity was measured for 8 days from postoperative day 3 to 10. Patients with substantial correlation between physical activity and postoperative day were classified as the “good-pacing” group. Patients with no correlation between them were classified as the “poor-pacing” group. They were also evaluated using a pain visual analog scale (VAS), pain catastrophizing scale, and hospital anxiety and depression scale.ResultsThe average age was 68 years, and 59 patients (82%) were women. The average maximum number of steps per day was 2,181. There were 45 patients with good pacing and 27 with poor pacing. The poor-pacing group showed significantly lower maximum number of steps per day, higher postoperative average VAS score, higher postoperative worst VAS score, and longer duration of postoperative hospital stay than the good-pacing group.ConclusionPatients with excessive variation in physical activity showed severe postoperative pain and prolonged postoperative hospital stay. The postoperative variation in physical activity could be an outcome for improvement in patients after lower-limb arthroplasty.

SUMMARYA complete genomic region of 131Á2 kb including the swine T-cell receptor a/d constant region (TRAC/TRDC) and joining segments (TRAJ/TRDJ) was sequenced. The structure of this region was strikingly conserved in comparison to that of human or mouse. All of the 61 TRAJ segments detected in the human genomic sequence were detected in the swine sequence and the sequence of the protein binding site of T early alpha, the sequence of the a enhancer element and the conserved sequence block between TRAJ3 and TRAJ4 are highly conserved. Insertion of the repetitive sequences that interspersed after the differentiation of the species in mammals such as short interspersed nucleotide elements is markedly suppressed in comparison to other genomic regions, while the composition of the mammalian-wide interspersed sequences is relatively conserved in human and swine. This observation indicates the existence of a highly selective pressure to conserve this genomic region around TRAJ throughout the evolution of mammals.