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Publications (6)25.96 Total impact

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    ABSTRACT: Design, synthesis and structure-activity relationship of a series of biphenylsulfonamido-3-methylbutanoic acid based aggrecanase-1 inhibitors are described. In addition to robust aggrecanase-1 inhibition, these compounds also exhibit potent MMP-13 activity. In cell-based cartilage explants assay compound 48 produced 87% inhibition of proteoglycan degradation at 10 μg/mL. Good pharmacokinetic properties were demonstrated by 46 with a half-life of 6h and bioavailability of 23%.
    Bioorganic & medicinal chemistry letters 11/2011; 21(22):6800-3. · 2.65 Impact Factor
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    ABSTRACT: The prevention of aggrecan (a key component of cartilage) cleavage via the inhibition of aggrecanase-1 may provide a unique opportunity to stop the progression of cartilage degradation in osteoarthritis. The evaluation of a series of biphenylsulfonamides resulted in the identification of the ((4-keto)-phenoxy)methyl biphenyl-4-sulfonamides analogs (19-21 and 24) with improved Agg-1 inhibition and MMP-2, MMP-13 activity.
    Bioorganic & medicinal chemistry letters 04/2009; 19(9):2487-91. · 2.65 Impact Factor
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    ABSTRACT: In the treatment of osteoarthritis (OA), some of the therapeutic approaches require delivery of drug(s) to the diseased cartilage. Presence of adequate drug levels in the cartilage is one of the important criteria in selection and ranking of lead compounds. The purpose of this study was to investigate the correlation in cartilage compound levels between in vitro experiments and in vivo animal studies. Bovine cartilage samples were incubated with test compounds of various concentrations in a culture medium, in the absence or presence of 25 mg/ml of serum albumin which served as an artificial synovial fluid (SF). The test compounds were also dosed to rabbits, the animal model used for efficacy studies, over a six-week treatment period. Test article concentrations in plasma, SF, and cartilage were determined by LC/MS/MS analysis. A correlation in cartilage drug concentration was observed between in vitro and in vivo studies. Plasma protein binding and the test article's affinity to cartilage were the major determining factors for drug delivery to cartilage in vivo.
    Pharmaceutical Research 08/2008; 25(7):1641-6. · 4.74 Impact Factor
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    ABSTRACT: Articular cartilage chondrocytes help in the maintenance of tissue homeostasis and function of the articular joint. Study of primary chondrocytes in culture provides information closely related to in vivo functions of these cells. Limitations in the primary culture of chondrocytes have lead to the development of cells lines that serve as good surrogate models for the study of chondrocyte biology. In this study, we report the establishment and characterization of chondrocyte cell lines, MM-Sv/HP and MM-Sv/HP-2 from mouse articular cartilage. Cells were isolated from mouse femoral head articular cartilage, immortalized and maintained in culture through numerous passages. The morphology of the cells was from fibroblastic to polygonal in nature. Gene expression studies using quantitative PCR (Q-PCR) were performed on cells in monolayer culture and cells embedded in a three-dimensional alginate matrix. Stimulation of cells in monolayer culture with anabolic factor, BMP-2, resulted in increased gene expression of the extracellular matrix molecules, aggrecan and type II collagen and their regulator transcription factor, Sox9. Treatment by pro-inflammatory IL-1 resulted in increased gene expression of catabolic effectors including Aggrecanases (ADAMTS4, ADAMTS5), MMP-13 and nitric oxide synthase (Nos2). Cells in alginate treated with BMP-2 resulted in increased synthesis of proteoglycan which was released into the conditioned media on IL-1 stimulation. Western analysis of conditioned media showed the presence of Aggrecanase-cleaved aggrecan fragments. In summary, MM-Sv/HP and MM-Sv/HP-2 show preservation of important characteristics of articular chondrocytes as examined under multiple culture conditions and would provide a useful reagent in the study of chondrocyte biology.
    Journal of Cellular Physiology 05/2008; 215(1):68-76. · 4.22 Impact Factor
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    ABSTRACT: Protein kinase Czeta (PKCzeta), an atypical PKC, has been found to be transcriptionally up-regulated in human osteoarthritic (OA) articular cartilage. This study was undertaken to examine the role of PKCzeta in interleukin-1beta (IL-1beta)-induced NF-kappaB signaling in human OA chondrocytes, and ultimately to better understand its function in the regulation of downstream mediators of cartilage matrix degradation. Pharmacologic inhibitors or genetic knockdown techniques were used to investigate the role of PKCzeta. Western blot analysis was used to evaluate phosphorylation of PKCzeta and NF-kappaB. Quantitative polymerase chain reaction (PCR) and activity assays were used to evaluate ADAMTS-4 expression and aggrecanase activity, respectively. Quantitative PCR, biochemical identification, and Western blot analysis were used to evaluate type 2 nitric oxide synthase (NOS2) and NO production. Phosphorylation of PKCzeta and NF-kappaB was induced by IL-1beta treatment in a time-dependent manner, and was specifically inhibited by inhibitors of atypical PKCs. Inhibition of PKCzeta suppressed IL-1beta-induced up-regulation of ADAMTS-4 messenger RNA (mRNA) and aggrecanase activity. Inhibitors of atypical PKCs also inhibited IL-1beta-induced NO production and NOS2 mRNA expression, demonstrating a novel link between PKCzeta and NO production. Furthermore, small interfering RNA- or short hairpin RNA-mediated knockdown of PKCzeta mRNA resulted in significant repression of both ADAMTS-4 and NOS2 mRNA expression. Our results show that PKCzeta is involved in the regulation of IL-1beta-induced NF-kappaB signaling in human OA chondrocytes, which in turn regulates downstream expression of ADAMTS-4 and NOS2. Therefore, inhibition of PKCzeta could potentially regulate the production of matrix-degrading enzymes as well as NO production and have a profound effect on disease progression in OA.
    Arthritis & Rheumatology 01/2008; 56(12):4074-83. · 7.48 Impact Factor
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    ABSTRACT: Chondrocytes are unique to cartilage and the study of these cells in vitro is important for advancing our understanding of the role of these cells in normal homeostasis and disease including osteoarthritis (OA). As there are limitations to the culture of primary chondrocytes, cell lines have been developed to overcome some of these obstacles. In this study, we developed a procedure to immortalize and characterize chondrocyte cell lines from mouse xiphisternum. The cells displayed a polygonal to fibroblastic morphology in monolayer culture. Gene expression studies using quantitative PCR showed that the cell lines responded to bone morphogenetic protein 2 (BMP-2) by increased expression of matrix molecules, aggrecan, and type II collagen together with transcriptional factor, Sox9. Stimulation by IL-1 results in the increased expression of catabolic effectors including MMP-13, nitric oxide synthase, ADAMTS4, and ADAMTS5. Cells cultured in alginate responded to BMP-2 by increased synthesis of proteoglycan (PG), a major matrix molecule of cartilage. IL-1 treatment of cells in alginate results in increased release of PG into the conditioned media. Further analysis of the media showed the presence of Aggrecanase-cleaved aggrecan fragments, a signature of matrix degradation. These results show that the xiphisternum chondrocyte cell lines preserve their chondrocyte phenotype cultured in either monolayer or 3-dimensional alginate bead culture systems. In summary, this study describes the establishment of chondrocyte cell lines from the mouse xiphisternum that may be useful as a surrogate model system to understand chondrocyte biology and to shed light on the underlying mechanism of pathogenesis in OA.
    Journal of Cellular Physiology 12/2006; 209(2):551-9. · 4.22 Impact Factor