title: Astrocytes synthesize and secrete prostaglandin D synthetase in vitro.
abstract: Prostaglandin D synthetase [PGD-S, prostaglandin-H2 D-isomerase, (5Z, 13E)-(15S)-9alpha, 11 alpha-epidioxy-15-hyrdroxyprosta-5,13-dienoate D-isomerase, EC 5,3,99,2], an enzyme that catalyzes the formation of prostaglandin D2, was originally isolated from homogenates of rat brain and spleen and is known to be a membrane-bound enzyme. Subsequent immunohistochemical studies have shown that PGD-S is associated with neurons in the brain of immature rats, whereas in adult rats it is associated with oligodendrocytes. Several recent studies have shown that the beta-trace protein isolated from human cerebrospinal fluid (CSF), the second most abundant protein in human CSF after albumin, is equivalent to PGD-S. In this paper, we report the preparation of a monospecific polyclonal antibody against purified PGD-S isolated from human CSF and the establishment of a specific radioimmunoassay for this protein. Using this radioimmunoassay in conjunction with immunoblot analysis, PGD-S was detected in various biological fluids including serum, aqueous humor, and rete testis fluid. In addition, an antibody prepared against human PGD-S partially cross-reacted with the PGD-S in the rat and ram. Using a monospecific polyclonal antibody prepared against purified rat PGD-S isolated from rat CSF in conjunction with [35S]methionine incorporation and immunoprecipitation techniques, it was shown for the first time that PGD-S is actively synthesized and secreted by astrocytes cultured in vitro, suggesting the astrocyte is the cellular origin of PGD-S in the CSF. The identification of the astrocyte as the cellular origin of this unique enzyme will allow the use of an in vitro system to study its regulation.
authors.affiliation: The Population Council, Center for Biomedical Research, NY 10021, USA.
authors.forename: S
authors.initials: S
authors.lastname: Giacomelli
authors.forename: M G
authors.initials: MG
authors.lastname: Leone
authors.forename: J
authors.initials: J
authors.lastname: Grima
authors.forename: B
authors.initials: B
authors.lastname: Silvestrini
authors.forename: C Y
authors.initials: CY
authors.lastname: Cheng
mesh_terms: D000375:Aging; D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies; D001082:Aqueous Humor / Q000378:metabolism; D001253:Astrocytes / Q000201:enzymology*; D001609:Beta-Globulins / Q000032:analysis / Q000096:biosynthesis* / Q000134:cerebrospinal fluid; D001667:Binding, Competitive; D001921:Brain / Q000201:enzymology* / Q000254:growth & development / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D019746:Intramolecular Oxidoreductases; D007535:Isomerases / Q000032:analysis / Q000096:biosynthesis* / Q000378:metabolism; D054834:Lipocalins; D008297:Male; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010455:Peptides / Q000138:chemical synthesis / Q000276:immunology; D014176:Protein Biosynthesis; D011817:Rabbits; D011863:Radioimmunoassay; D051381:Rats; D012156:Reticulocytes; D012559:Schizophrenia / Q000134:cerebrospinal fluid; D013737:Testis / Q000378:metabolism
chemical_list: D000906:Antibodies; D001609:Beta-Globulins; D054834:Lipocalins; D010455:Peptides; D007535:Isomerases; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase