Home About us Contact
|
Home About us Contact | ||
|
|
||
Matrix Metabolism (matrix + metabolism)
Selected AbstractsSynthesis, Solution Structure and Biological Activity of Val-Val-Pro-Gln,a Bioactive Elastin PeptideEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 8 2005Caterina Spezzacatena Abstract Val-Val-Pro-Gln (valyl-valyl-prolyl-glutamine) is a small but highly conserved sequence present in all elastins. We describe its synthesis by mixed anhydride solution chemistry as an alternative to solid-phase peptide synthesis (SPPS). The molecular structure of the tetrapeptide in solution was investigated by classical spectroscopy, such as circular dichroism (CD), nuclear magnetic resonance (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). The biological activity of Val-Val-Pro-Gln was evaluated by a bromodeoxyuridine (BrdU) incorporation assay with normal human dermal fibroblasts. This small peptide may play a critical role in control of matrix metabolism through its release from the elastin polypeptide chain during periods of tissue breakdown and remodelling. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Functional analysis of CBP/p300 in embryonic orofacial mesenchymal cellsJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 5 2006D.R. Warner Abstract CREB binding protein (CBP) and the close structural homolog, p300, are nuclear coactivators of multiple signaling pathways that play important roles in embryonic development and cellular homeostasis. TGF, regulates the proliferation rate of many cell types and has been demonstrated to inhibit the growth rate of mouse embryonic maxillary mesenchymal (MEMM) cells. The role of CBP and p300 in TGF,-mediated control of proliferation of MEMM cells was thus investigated using an in vitro gene knockdown approach. TGF, reporter assays demonstrated that p300 mRNA knockdown via targeted siRNAs led to a reduction in the response to TGF,, whereas knockdown of CBP by the same approach had an insignificant effect. In MEMM cell proliferation assays, siRNA-mediated knockdown of CBP and/or p300 had little impact upon TGF,-mediated growth inhibition; however, the basal rate of proliferation was increased. Inhibition of p300 activity via overexpression of a dominant-negative mutant (p300,C/H3) led to significant inhibition of TGF,-mediated activation of p3TP-lux. As with the siRNA knockdown approach, p300,C/H3 also increased the basal rate of cell proliferation of MEMM cells. CBP/p300 siRNA knockdown had a significant but incomplete inhibition of TGF,-induction of matrix metalloproteinase-9 (gelatinase B) expression. These data demonstrate that p300 is involved in Smad-mediated transcription of p3TP-lux, however, its role (and that of CBP) in biological processes such as the control of cell proliferation and extracellular matrix metabolism is more complex and may be mediated via mechanisms beyond coactivator recruitment. J. Cell. Biochem. 99: 1374,1379, 2006. © 2006 Wiley-Liss, Inc. [source] Transcriptional and proteolytic regulation of the insulin-like growth factor-I system of equine articular chondrocytes by recombinant equine interleukin-1,JOURNAL OF CELLULAR PHYSIOLOGY, Issue 2 2006Ryan M. Porter Interleukin-1 (IL-1) and insulin-like growth factor-I (IGF-I), which have opposing effects on matrix metabolism within articular cartilage, are thought to play prominent roles in the pathogenesis of osteoarthritis. To better understand the link between these anabolic (IGF-I) and catabolic (IL-1) stimuli, we examined exogenous IL-1 regulation of the IGF-I signaling system of articular chondrocytes (ACs). Equine ACs from non-arthritic stifle joints were expanded in monolayer culture, encapsulated for 10 days in alginate beads, and stimulated as high-density monolayers with recombinant equine IL-1, (0, 1, 10 ng/ml) for 48 h. IL-1, enhanced expression of IGF-IR levels, as determined by both [125I]-IGF-I binding studies and Western blotting, while reducing the concentration of endogenous IGF-I detected in conditioned media by radioimmunoassay. Western ligand blotting revealed that chondrocytes primarily secreted IGF binding proteins (IGFBPs) with molecular weights of 28,30 and 32,34 kDa, which were identified as IGFBPs 5 and 2, respectively, and that IL-1, treatment diminished IGFBP-2, the prominent homolog in conditioned media. Northern blot analysis suggested IL-1, regulation of IGF-I and, to some extent, IGF-IR was mediated by transcription; however, the cytokine did not affect IGFBP-2 expression. To test for evidence of proteolysis by matrix metalloproteinases (MMPs), additional cultures were co-incubated with inhibitors for MMPs 2/9, 3, and 8. IGFBP-2 suppression was partially reversed by gelatinase (MMP-2/9) inhibition. In summary, these findings further delineate the role of IL-1 as a key regulator of the IGF-I system within articular cartilage, demonstrating that regulation occurs through both direct (transcriptional) and indirect (proteolytic) mechanisms. J. Cell. Physiol. 209: 542,550, 2006. © 2006 Wiley-Liss, Inc. [source] Effect of vertebroplasty filler materials on viability and gene expression of human nucleus pulposus cellsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2008Áron Lazáry Abstract Consequences of intradiscal cement leakage,often occurring after vertebral cement augmentation for the treatment of vertebral compression fractures,are still unknown. In this study, we have investigated the influences of vertebroplasty filler materials (polymethylmethacrylate-, calcium phosphate- and calcium sulfate-based bone cement) on isolated nucleus pulposus cells. Cell viability of cultured human nucleus pulposus cells were measured after treatment with vertebroplasty filler materials. Gene expression profile of selected genes was determined with quantitative real-time PCR. The widely used polymethylmethacrylate and calcium phosphate cement significantly decreased cell number in a dose- and time-dependent manner while calcium sulfate cement affected cell viability less. Expression of genes involved in matrix metabolism of nucleus pulposus,aggrecan, collagens, small proteoglycans,as well as important transcription factors have also significantly changed due to treatment (e.g., 2.5-fold decrease in aggrecan expression was determined in cultures due to polymethylmethacrylate treatment). Our results suggest that vertebroplasty filler materials,depending on the type of applied material,can accelerate the degeneration of nucleus pulposus cells resulting in a less flexible disc in case of intradiscal cement leakage. This process may increase the risk of a subsequent new vertebral fracture, the main complication of vertebral augmentation. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:601,607, 2008 [source] Repeated intraarticular injections of triamcinolone acetonide alter cartilage matrix metabolism measured by biomarkers in synovial fluidJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2005Christophe Céleste Abstract Although intraarticular (IA) corticosteroids are frequently used to treat joint disease, the effects of their repeated use on articular cartilage remains controversial. The aim of our study was to determine the effects of a clinically recommended dose of IA triamcinolone acetonide (TA), on synovial fluid (SF) biomarkers of cartilage metabolism. Ten adult horses, free of osteoarthritis (OA) in their radiocarpal joints, were studied. One radiocarpal joint of each horse was randomly chosen for treatment and the contralateral anatomically paired joint acted as the control. Aseptic arthrocentesis was performed weekly on both joints for 13 weeks. The initial results from the first 3 weeks of the experimental period established baseline untreated control marker levels for each joint, each being its own control. On weeks 3, 5, and 7, a sterile suspension of 12mg of TA was injected into the treated joint and an equivalent volume of sterile saline solution (0.9%) was injected into the control joint. SF was immunoassayed for biomarkers of aggrecan turnover (CS 846 & KS), types I and II collagen cleavage (C1,2C) and type II collagen synthesis (CPII). In treated joints, there was a significant increase in CS 846, KS, C1,2C and CPII epitope concentrations following IA TA injections when compared to baseline levels. There was also a significant increase in C1,2C and CPII epitope concentrations in the contralateral control joints following IA TA injections in the treated joint. Significant differences were observed between treated and control joints for all markers except CPII. These findings indicate that TA alters articular cartilage and collagen metabolism in treated and, interestingly, also in control joints, suggesting a systemic effect of the drug. Though intuitively the observed findings would favor the hypothesis that long-term IA TA treatment changes joint metabolism and this may have detrimental effects; further studies would be necessary to confirm this. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] Comparative analysis of gene expression profiles between primary knee osteoarthritis and an osteoarthritis endemic to Northwestern China, Kashin-Beck diseaseARTHRITIS & RHEUMATISM, Issue 3 2010Chen Duan Objective To investigate the differences in gene expression profiles of adult articular cartilage from patients with Kashin-Beck disease (KBD) versus those with primary knee osteoarthritis (OA). Methods The messenger RNA expression profiles of articular cartilage from patients with KBD, diagnosed according to the clinical criteria for KBD in China, were compared with those of cartilage from patients with OA, diagnosed according to the Western Ontario and McMaster Universities OA Index. Total RNA was isolated separately from 4 pairs of the KBD and OA cartilage samples, and the expression profiles were evaluated by Agilent 4×44k Whole Human Genome density oligonucleotide microarray analysis. The microarray data for selected transcripts were confirmed by quantitative real-time reverse transcription,polymerase chain reaction (RT-PCR) amplification. Results For 1.2 × 104 transcripts, corresponding to 58.4% of the expressed transcripts, 2-fold changes in differential expression were revealed. Expression levels higher in KBD than in OA samples were observed in a mean ± SD 6,439 ± 1,041 (14.6 ± 2.4%) of the transcripts, and expression levels were lower in KBD than in OA samples in 6,147 ± 1,222 (14.2 ± 2.8%) of the transcripts. After application of the selection criteria, 1.85% of the differentially expressed genes (P < 0.001 between groups) were detected. These included 233 genes, of which 195 (0.4%) were expressed at higher levels and 38 (0.08%) were expressed at lower levels in KBD than in OA cartilage. Comparisons of the quantitative RT-PCR data supported the validity of our microarray data. Conclusion Differences between KBD and OA cartilage exhibited a similar pattern among all 4 of the pairs examined, indicating the presence of disease mechanisms, mainly chondrocyte matrix metabolism, cartilage degeneration, and apoptosis induction pathways, which contribute to cartilage destruction in KBD. [source] | ||||||||||