Structural refinement of seco-steroidal skeleton and the biological activity through nuclear receptors.
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1alpha,25-Dihydroxyvitamin D(3) (1) regulates a variety of biological actions through vitamin D receptor (VDR), including calcium and phosphorus homeostasis, bone remodeling, cellular proliferation and differentiation and many other functions. To enhance its potency and to study the structure/function relationship, we synthesized a series of analogs of 1 with a modification at the C-2alpha position. Introducing 2alpha-methyl, 2alpha-(3-hydroxypropyl), or 2alpha-(3-hydroxypropoxy) group increased its binding affinity for the VDR 2- to 4-fold compared to 1. The crystal structures of the VDR bound to these analogs provide a molecular explanation for the interaction between the 2alpha-substituents and water molecules exist in the VDR-ligand binding domain. Based on the accumulated knowledge in VDR agonists, we synthesized 2-substituted analogs of 'double side chain' (gemini), 19-norvitamin D(3) (MART-10), TEI-9647 (VDR antagonist), 1-alkylated vitamin D(3), 14-epi-previtamin D(3) etc. Gemini analogs showed potent HL-60 cell differentiation activity (13-38 times compared to 1), and MART-10 exhibited remarkable antiproliferative activity on PZ-HPV-7 cells even at 10(-10) M. (24S)-2alpha-(3-Hydroxypropoxy)-24-propyl-TEI-9647 showed potent VDR antagonism, and its IC(50) value was 7.4 pM against 10 nM of 1. 1alpha-Methyl-2alpha-(3-hydroxypropyl)-25-hydroxyvitamin D(3) improved the binding affinity for the mutant VDR(Arg274Leu), which causes hereditary vitamin D resistant rickets. 1alpha,25-Dihydroxy-2alpha-methyl-14-epi-previtamin D(3) showed moderate osteocalcin transcriptional activity on HOS cells. We theorize that modification at A-ring alone and in combination with functionalization of the other parts of the vitamin D molecule would provide important new information on the mechanism of vitamin D actions that could lead to the development of new therapeutic regimes for the treatment of various diseases. (+info)
A proteomic analysis of IVF follicular fluid in women
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Genetic polymorphisms of the vitamin D binding protein and plasma concentrations of 25-hydroxyvitamin D in premenopausal women.
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Population studies of intact vitamin D binding protein by affinity capture ESI-TOF-MS.
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Blood plasma proteins with molecular weights greater than approximately 30 kDa are refractory to comprehensive, high-throughput qualitative characterization of microheterogeneity across human populations. Analytical techniques for obtaining high mass resolution for targeted, intact protein characterization and, separately, high sample throughput exist, but efficient means of coupling these assay characteristics remain rather limited. This article discusses the impetus for analyzing intact proteins in a targeted manner across populations and describes the methodology required to couple mass spectrometric immunoassay with electrospray ionization mass spectrometry for the purpose of qualitatively characterizing a prototypical large plasma protein, vitamin D binding protein, across populations. (+info)
Effects of receptor-mediated endocytosis and tubular protein composition on volume retention in experimental glomerulonephritis.
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Vitamin D3 binding protein (group-specific component) is a precursor for the macrophage-activating signal factor from lysophosphatidylcholine-treated lymphocytes.
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A brief (30 min) treatment of mouse peritoneal cells (mixture of nonadherent lymphocytes and adherent macrophages) with 1-20 micrograms of lysophosphatidylcholine (lyso-PC) per ml in serum-supplemented RPMI medium 1640, followed by a 3-hr cultivation of the adherent cells alone, results in a greatly enhanced Fc receptor-mediated phagocytic activity of macrophages. This rapid process of macrophage activation was found to require a serum factor, the vitamin D3 binding protein (the human protein is known as group-specific component; Gc). Efficient activation of macrophages was achieved by using medium containing purified human Gc protein. Analysis of intercellular signal transmission among nonadherent (B and T) cells revealed that lyso-PC-treated B cells modify Gc protein to yield a proactivating factor, which can be converted by T cells to the macrophage-activating factor. This rapid generation process of the macrophage-activating factor was also demonstrated by stepwise incubation of Gc protein with lyso-PC-treated B-cell ghosts and untreated T-cell ghosts, suggesting that Gc protein is modified by preexisting membranous enzymes to yield the macrophage-activating factor. Incubation of Gc protein with a mixture of beta-galactosidase and sialidase efficiently generated the macrophage-activating factor. Stepwise incubation of Gc protein with B- or T-cell ghosts and sialidase or beta-galactosidase revealed that Gc protein is modified by beta-galactosidase of B cells and sialidase of T cells to yield the macrophage-activating factor. Administration to mice of a minute amount (4-10 pg per mouse) of in vitro, enzymatically generated macrophage-activating factor resulted in a greatly enhanced (3- to 7-fold) ingestion activity of macrophages. (+info)
Genetic polymorphisms in vitamin D receptor, vitamin D-binding protein, Toll-like receptor 2, nitric oxide synthase 2, and interferon-gamma genes and its association with susceptibility to tuberculosis.
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