G Mohan Shankar

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Murine CD4 and CD8 T cells express predominantly types 1 and 4 sphingosine 1-phosphate (S1P) G protein-coupled receptors (designated S1P1 and S1P4 or previously endothelial differentiation gene-encoded 1 and 6) for S1P, which has a normal plasma concentration of 0.1-1 microM. S1P now is shown to enhance chemotaxis of CD4 T cells to CCL-21 and CCL-5 by up to(More)
The effects of endothelin-1 (ET) on several tissues are mediated by prostaglandins. In this study, we investigated the actions of ET on bone and determined whether they are mediated through prostaglandin-dependent pathways. Bone resorption, collagen, and non-collagen protein synthesis and inositol phosphate (IP) production were studied in neonatal mouse(More)
The extracellular matrix of bone is composed mainly of type I collagen. In this report we studied the role and collagen-binding properties of osteoclast integrins (alpha v, alpha 2, beta 1, and beta 3). Cell adhesion assays with rat osteoclasts and affinity chromatography/SDS-PAGE analysis with purified human osteoclast membranes demonstrated adhesion of(More)
Cell-matrix interactions have been shown to play an important role in regulating cell function and behaviour. In bone, where calcified matrix formation and resorption events are required to be in dynamic equilibrium, regulation of adhesive interactions between bone cells and their matrix is critical. The present study focuses on the osteoclast, the bone(More)
Bacterial lipopolysaccharide (LPS) is a potent stimulant of B cells and macrophages. LPS induces B cell proliferation and differentiation into antibody secreting cells. In addition, LPS also stimulates IL-6 secretion in mature B cells and in immature B cell lines such as WEHI-231. Although sufficient literature is available on LPS induced signaling events(More)
Lysophosphatidic acid (LPA), sphingosine 1-phosphate (S1P) and some other structurally related lysophospholipids are active growth factors and stimuli for diverse cellular functions. LPA and S1P promote early T cell migration to tissue sites of immune responses and regulate T cell proliferation and secretion of numerous cytokines. Edg-4 (LPA2) LPA(More)
Extensive characterization of the vitronectin receptor (VNR), a member of the integrin group of cell adhesion molecules, which is abundantly expressed in osteoclasts, has revealed a role for this receptor in osteoclast adhesion as well as bone resorption. Earlier evidence from our laboratory suggests that VNR is also capable of transducing intracellular(More)
Tumor necrosis factor (TNF) actions in target tissues are mediated by various signalling pathways. The effect of TNF to stimulate resorption in fetal rat limb bones is not inhibited by indomethacin. The current studies were designed to assess the role of cyclic AMP (cAMP) and calcium as second messengers in this prostaglandin-independent action of TNF on(More)
The binding and pharmacological characteristics of the melatonin site labeled by the radioligand 2-[125I]iodomelatonin in chicken brain membranes were determined and compared with those of the melatonin site of chicken retinal membranes. The specific binding of 2-[125I]iodomelatonin to chicken brain membranes was found to be stable, saturable, reversible(More)
G protein-coupled receptors (GPCRs) for lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) transduce signals to many functions of normal cells. Most human cancer cells upregulate S1P and LPA GPCRs, in patterns distinctive for each type of tumor. The findings that 1-alpha, 25-dihydroxy-vitamin D(3) (VD3) and all-trans retinoic acid (RA)(More)