Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purpose of this paper is to summarize recent advances in our understanding of the physiological role of 24(R),25(OH)(2)D(3) in bone and cartilage and its mechanism of action. With the identification of a target cell, the growth plate resting zone (RC) chondrocyte, we have been able to use cell biology methodology to investigate specific functions of 24(R),25(OH)(2)D(3) and to determine how 24(R),25(OH)(2)D(3) elicits its effects. These studies indicate that there are specific membrane-associated signal transduction pathways that mediate both rapid, nongenomic and genomic responses of RC cells to 24(R),25(OH)(2)D(3). 24(R),25(OH)(2)D(3) binds RC chondrocyte membranes with high specificity, resulting in an increase in protein kinase C (PKC) activity. The effect is stereospecific; 24R,25(OH)(2)D(3), but not 24S,25-(OH)(2)D(3), causes the increase, indicating a receptor-mediated response. Phospholipase D-2 (PLD2) activity is increased, resulting in increased production of diacylglycerol (DAG), which in turn activates PKC. 24(R),25(OH)(2)D(3) does not cause translocation of PKC to the plasma membrane, but activates existing PKCalpha. There is a rapid decrease in Ca(2+) efflux, and influx is stimulated. 24(R),25(OH)(2)D(3) also reduces arachidonic acid release by decreasing phospholipase A(2) (PLA(2)) activity, thereby decreasing available substrate for prostaglandin production via the action of cyclooxygenase-1. PGE(2) that is produced acts on the EP1 and EP2 receptors expressed by RC cells to downregulate PKC via protein kinase A, but the reduction in PGE(2) decreases this negative feedback mechanism. Both pathways converge on MAP kinase, leading to new gene expression. One consequence of this is production of new matrix vesicles containing PKCalpha and PKCzeta and an increase in PKC activity. The chondrocytes also produce 24(R),25(OH)(2)D(3), and the secreted metabolite acts directly on the matrix vesicle membrane. Only PKCzeta is directly affected by 24(R),25(OH)(2)D(3) in the matrix vesicles, and activity of this isoform is inhibited. This effect may be involved in the control of matrix maturation and turnover. 24(R),25(OH)(2)D(3) causes RC cells to mature along the endochondral developmental pathway, where they become responsive to 1alpha,25(OH)(2)D(3) and lose responsiveness to 24(R),25(OH)(2)D(3), a characteristic of more mature growth zone (GC) chondrocytes. 1alpha,25(OH)(2)D(3) elicits its effects on GC through different signal transduction pathways than those used by 24(R),25(OH)(2)D(3). These studies indicate that 24(R),25(OH)(2)D(3) plays an important role in endochondral ossification by regulating less mature chondrocytes and promoting their maturation in the endochondral lineage.
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PMID:24,25-(OH)(2)D(3) regulates cartilage and bone via autocrine and endocrine mechanisms. 1117 45

Anti-inflammatory activities of ethanol extracts from nine vine plants used in traditional Chinese medicine to treat inflammatory conditions were evaluated against a panel of key enzymes relating to inflammation. The enzymes included cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), phospholipase A(2) (PLA(2)), 5-lipoxygenase (5-LO) and 12-lipoxygenase (12-LO). The vine plants studied were: the stem of Spatholobus suberectus Dunn, the stem of Trachelospermum jasminoides Lem., the root from Tripterygium wilfordii Hook. f., the stem of Sinomenium acutum Rehder and Wilson, the stem of Piper kadsura (Choisy) Ohwi, the stem of Polygonum multiflorum Thunb., the root and stem from Tinospora sagittata Gagnep., the root of Tinospora sinensis (Lour.) Merrill, and the stem of Clematis chinensis Osbeck. All of the plant extracts showed inhibitory activities against at least one of the enzymes in various percentages depending upon the concentrations. The extract from S. suberectus was found to be active against all enzymes except COX-2. Its IC(50) values were 158, 54, 31 and 35 microg/ml in COX-1, PLA(2), 5-LO and 12-LO assays, respectively. T. jasminoides showed potent inhibitory activities against both COX-1 (IC(50) 35 microg/ml) and PLA(2) (IC(50) 33 microg/ml). The most potent COX-1, COX-2 and 5-LO inhibition was observed in the extract of T. wilfordii with the IC(50) values of 27, 125 and 22 microg/ml, respectively. The findings of this study may partly explain the use of these vine plants in traditional Chinese medicine for the treatment of inflammatory conditions.
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PMID:Anti-inflammatory activity of Chinese medicinal vine plants. 1257 3

Nutrition plays a critical role in the regulation of cow fertility. There is emerging evidence that dietary long chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) may act as specific regulators of some reproductive processes. In vitro studies suggest that the n-3 PUFAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) may play pivotal roles by suppressing the synthesis of uterine prostaglandin F(2alpha) (PGF(2alpha)) which is centrally involved in the control of the bovine oestrous cycle and in early embryo survival. The objective of the current study was to determine the effect of dietary inclusion of n-3 PUFA on uterine endometrial mRNA expression of key genes regulating PGF(2alpha) biosynthesis. Beef heifers were fed either a low (CON; n=10) or high (HIGH PUFA; n=10) n-3 PUFA diet for 45 days and endometrial tissues were harvested following slaughter. Following analysis, tissues within each dietary group were ranked on the basis of their PUFA concentrations and the highest (n=7) and lowest (n=7) within each of HIGH PUFA and CON, respectively, were used in gene expression studies. Endometrial n-3 PUFA concentrations were more than two-fold higher (P<0.05) and EPA concentrations alone more than seven-fold higher (P<0.01) in the HIGH PUFA than the CON group. Endometrial concentrations of arachidonic acid, were lower (P<0.001) in the tissues from HIGH PUFA than those from the CON group. Total RNA was isolated from all endometrial tissues and real-time reverse transcription (RT) PCR conducted to compare the relative expression of 11 genes with known involvement in uterine biosynthesis of 2-series prostaglandins. Expression of mRNA for prostaglandin E synthase (PGES) and peroxisome proliferator-activated receptors, PPAR alpha and delta was increased (P<0.05) while mRNA expression of phospholipase A(2) (PLA(2)) was decreased (P=0.06) in the HIGH PUFA endometrial tissues. Expression of genes coding for the oxytocin receptor (OTR), phospholipase C (PLC), cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), PGE(2) 9-ketoreductase (9-KPR), prostaglandin F synthase (PGFS), and the nuclear transcription factor, PPAR gamma was not different (P>0.05) between HIGH PUFA and CON tissues. Overall the results indicate that key genes regulating uterine PGF(2alpha) biosynthesis can be regulated by dietary inclusion of LC n-3 PUFA which may influence uterine function and embryo survival.
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PMID:Dietary n-3 polyunsaturated fatty acids alter the expression of genes involved in prostaglandin biosynthesis in the bovine uterus. 1858 26

The effect of lovastatin, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, on prostacyclin production was studied in cultured human umbilical vein endothelial cells. The results indicated that lovastatin induced a significant dose- and time-dependent decrease of arachidonic acid release from the cells, an inhibition of phospholipase A(2) (PLA(2)) activity, a reduction of [(3)H]choline in lysophosphatidylcholine (lysoPC), and a diminishment of (45)Ca(2+) influx into the cells. The decreased arachidonic acid release was not reversed by addition of either intermediate products during cholesterol synthesis, such as mevalonate, geranylgeraniol, farnesol, or cholesterol and lipoprotein although a reduced concentration of cholesterol in the cells, caused by lovastatin, was reversed by added cholesterol. Lovastatin, furthermore, diminished prostacyclin production and inhibited activity of cyclooxygenase-1. 27-Hydroxycholesterol (27OHC), an oxidized cholesterol, had the same effect on HMG-CoA reductase as lovastatin, but 27OHC increased arachidonic acid release and (45)Ca(2+) influx. Our results indicated that lovastatin inhibited significantly activities of PLA(2) and cyclooxygenase-1, resulting in a marked reduction in arachidonic acid release, lysoPC content and prostacyclin production in the cultured vascular endothelial cells.
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PMID:High-dose lovastatin decreased basal prostacyclin production in cultured endothelial cells. 1913 46

Phosphocitrate (PC) inhibited meniscal calcification and the development of calcium crystal-associated osteoarthritis (OA) in Hartley guinea pigs. However, the mechanisms remain elusive. This study sought to examine the biological activities of PC in the absence of calcium crystals and test the hypothesis that PC is potentially a meniscal protective agent. We found that PC downregulated the expression of many genes classified in cell proliferation, ossification, prostaglandin metabolic process, and wound healing, including bloom syndrome RecQ helicase-like, cell division cycle 7 homolog, cell division cycle 25 homolog C, ankylosis progressive homolog, prostaglandin-endoperoxide synthases-1/cyclooxygenase-1, and plasminogen activator urokinase receptor. In contrast, PC stimulated the expression of many genes classified in fibroblast growth factor receptor signaling pathway, collagen fibril organization, and extracellular structure organization, including fibroblast growth factor 7, collagen type I, alpha 1, and collagen type XI, alpha 1. Consistent with its effect on the expression of genes classified in cell proliferation, collagen fibril organization, and ossification, PC inhibited the proliferation of OA meniscal cells and meniscal cell-mediated calcification while stimulating the production of collagens. These findings indicate that PC is potentially a meniscal-protective agent and a disease-modifying drug for arthritis associated with severe meniscal degeneration.
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PMID:Biological activities of phosphocitrate: a potential meniscal protective agent. 2393 39