A cDNA clone of prostaglandin F synthase (PGFS) was isolated from human lung by using cDNA of bovine lungtype PGFS as a probe and its protein expressed in Escherichia coli was purified to apparent homogeneity. The human PGFS catalyzed the reduction of prostaglandin (PG) D 2 , PGH 2 and phenanthrenequinone (PQ), and the oxidation of 9K K,11L L-PGF 2 to PGD 2 . The k cat /K m values for PGD 2 and 9K K,11L L-PGF 2 were 21 000 and 1800 min 31 mM 31 , respectively, indicating that the catalytic efficiency for PGD 2 and 9K K,11L L-PGF 2 was the highest among the various substrates, except for PQ. The PGFS activity in the cytosol of human lung was completely absorbed with antihuman PGFS antiserum. Moreover, mRNA of PGFS was expressed in peripheral blood lymphocytes and the expression in lymphocytes was markedly suppressed by the T cell mitogen concanavalin A. These results support the notion that human PGFS plays an important role in the pathogenesis of allergic diseases such as asthma.z 1999 Federation of European Biochemical Societies.

Although the secreted phospholipase A 2 (sPLA 2 ) family has been generally thought to participate in pathologic events such as inflammation and atherosclerosis, relatively high and constitutive expression of group X sPLA 2 (sPLA 2 -X) in restricted sites such as reproductive organs, the gastrointestinal tract, and peripheral neurons raises a question as to the roles played by this enzyme in the physiology of reproduction, digestion, and the nervous system. Herein we used mice with gene disruption or transgenic overexpression of sPLA 2 -X to clarify the homeostatic functions of this enzyme at these locations. Our results suggest that sPLA 2 -X regulates 1) the fertility of spermatozoa, not oocytes, beyond the step of flagellar motility, 2) gastrointestinal phospholipid digestion, perturbation of which is eventually linked to delayed onset of a lean phenotype with reduced adiposity, decreased plasma leptin, and improved muscle insulin tolerance, and 3) neuritogenesis of dorsal root ganglia and the duration of peripheral pain nociception. Thus, besides its inflammatory action proposed previously, sPLA 2 -X participates in physiologic processes including male fertility, gastrointestinal phospholipid digestion linked to adiposity, and neuronal outgrowth and sensing.

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The enzyme steroid 5alpha-reductase catalyzes the production of dihydroprogesterone and dihydrotestosterone, which were recently recognized as neurosteroids in the brain with variably potential neuroactivity. The present study reports for the first time detailed localization of 5alpha-reductase type 1 in the rat main olfactory bulb. The occurrence of 5alpha-reductase in the olfactory bulb was detected by reverse transcription-polymerase chain reaction and Western blotting analyses. In addition, the enzyme activity was also detected by thin layer chromatography. Immunocytochemistry showed that 5alpha-reductase immunoreactive cells of variable intensity were present in all layers of the olfactory bulb. Multiple immunolabeling revealed that 5alpha-reductase was mainly localized in glial cells, namely, in S-100beta- and glial fibrillary acidic protein-immunoreactive astrocytes, 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNPase)-immunoreactive oligodendrocytes, and in S-100beta- and neuropeptide-Y-immunoreactive olfactory ensheathing cells, whereas the bulbar neurons exhibited little immunoreactivity. Quantitative analysis revealed that the number of 5alpha-reductase-immunoreactive cells was greatest in the olfactory nerve layer. The most intense 5alpha-reductase-immunoreactivity was found in the olfactory ensheathing cells, and next in the CNPase-immunoreactive cells. The 5alpha-reductase in the olfactory bulb was expressed constantly throughout different ages and sexes and in neutered and hypophysectomized rats. Thus, 5alpha-reductase may contribute via 5alpha-reduced metabolites to the formation and maintenance of olfactory inputs and outputs, which were closely associated with the olfactory ensheathing cells and the oligodendrocytes, respectively.

Prostaglandin E2 (PGE2), which is a potent pro-inflammatory lipid mediator, is biosynthesized from arachidonic acid by cyclooxygenase-2 (COX-2) and microsomal PGE synthase-1 (mPGES-1). Non-steroidal anti-inflammatory drugs (NSAIDs) are used clinically as COX inhibitors, but they have gastrointestinal and cardiovascular side-effects. Thus, the terminal enzyme mPGES-1 holds promise as the next therapeutic target. In this study, we found that the ellagitannins granatin A and granatin B isolated from pomegranate leaves, and geraniin, which is their structural analog, selectively suppressed mPGES-1 expression without affecting COX-2 in non-small cell lung carcinoma A549 cells. The ellagitannins also down-regulated tumor necrosis factor α, inducible nitric oxide synthase, and anti-apoptotic factor B-cell chronic lymphocytic leukemia/lymphoma 2, and induced A549 cells to undergo apoptosis. These findings indicate that the ellagitannins have anti-inflammatory and anti-carcinogenic effects, due to their specific suppression of mPGES-1. Abbreviations: Bcl-2: B-cell chronic lymphocytic leukemia/lymphoma 2; COX: cyclooxygenase; CRE: cAMP response element; DHHDP: dehydrohexahydroxydiphenoyl; Et2O: diethyl ether; EtOAc: ethyl acetate; GAPDH: glyceraldehyde 3-phosphate dehydrogenase; iNOS: inducible nitric oxide synthase; mPGES-1: microsomal prostaglandin E synthase-1; n-BuOH: water-saturated n-butanol; NSAIDs: non-steroidal anti-inflammatory drugs; NF-κB: nuclear factor-κB; PG: prostaglandin; TNF: tumor necrosis factor; TUNEL: terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling

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Prostaglandin (PG) F synthase forms PGF(2alpha) and 9alpha, 11beta-PGF2 from PGH2 and PGD2, respectively. PGH2 is synthesized from arachidonic acid by cyclooxygenase (COX) and then metabolized to various PGs and thromboxane by specific enzymes. PGD2 is synthesized from PGH2 by PGD synthase. To identify PGF2-producing cells in the rat liver, the occurrence and localization of PGF synthase and COX were studied with immunochemical and immunohistochemical techniques using anti-liver-type PGF synthase and anti-COX antibodies. In Western blot analyses, positive bands of liver-type PGF synthase and constitutive COX-1 were observed at positions approximately 37 kDa and 70-72 kDa, respectively. However, inducible COX-2 was not detected. In the immunohistochemical study, PGF synthase was present in the cytoplasm of the sinusoidal endothelial cells. COX-1 was present on the membranes of the nucleus and endoplasmic reticulum of the endothelial cells and Kupffer cells. Double immunostaining for PGF synthase and COX-1 showed that both enzymes were present in the same endothelial cells. These results suggest that the main site of PGF2 synthesis in the liver is the sinusoidal endothelial cell.