Hydroxylase Expression (hydroxylase + expression)

Distribution by Scientific Domains

Selected Abstracts

The Absence of Phosphorylated Tyrosine Hydroxylase Expression in the Purkinje Cells of the Ataxic Mutant Pogo Mouse

N. S. Lee
Summary The pogo mouse is a new ataxic autosomal recessive mutant that arose in Korean wild mice (KJR/Mskist). Its ataxic phenotype includes difficulty in maintaining a normal posture and the inability to walk in a straight line. Several studies have reported that tyrosine hydroxylase (TH) is persistently ectopically expressed in particular subsets of Purkinje cells in a parasagittal banding pattern in several ataxic mutant mice, e.g. tottering alleles and pogo mice. In this present study, we examined the expression of an enzymatically active form of TH and phosphorylated TH at Ser40 (phospho-TH) by using immunohistochemistry and double immunofluorescence in the cerebellum of pogo mice. TH immunostaining appeared in some Purkinje cells in pogo, but in only a few of Purkinje cells of their heterozygous littermate controls. In all groups of mice, no phospho-TH immunoreactive Purkinje cells were observed in the cerebellum, although subsets of TH immunoreactive Purkinje cells were found in adjacent sections. This study suggests that TH expression in the Purkinje cells of pogo abnormally increases without activation of this enzyme by phosphorylation. This may mean that TH in the Purkinje cells of these mutants does not catalyse the conversion of tyrosine to l -DOPA, and is not related to catecholamine synthesis. [source]

Early and transient ontogenetic expression of the cocaine- and amphetamine-regulated transcript peptide in the rat mesencephalon: Correlation with tyrosine hydroxylase expression

F. Brischoux
Abstract The ontogeny of cocaine- and amphetamine-regulated transcript (CART) expression has been analyzed by immunohistochemistry in the mesencephalon of the rat central nervous system, and compared to the pattern of tyrosine hydroxylase- (TH-) expression. CART-producing neurons were first detected on the embryonic day 11 (E11) in the ventral mesencephalic vesicle. These neurons are among the first cells of the mantle layer to differentiate. From E13, a complementary pattern of distribution was observed, dividing the mantle layer into an external TH zone and an internal CART zone. Many TH-positive neurons were found to migrate from the neuroepithelium through the area containing the CART-immunoreactive neurons to settle more laterally. These TH cells exhibited prominent leading and trailing dendrites in the immediate vicinity of CART perikarya. On E16, the number of CART neurons appeared to diminish, and they were confined near the ventricle and around the fasciculus retroflexus. On E18 and E20, only the Edinger-Westphal nucleus exhibited a strong CART staining as described in the adult brain. Thus, the very early detection of CART during prenatal ontogeny led us to speculate that this peptide might have a role in the development of specific regions of the rat brain. In particular, our observations suggest that CART-expressing neurons might help the migration of the dopaminergic neurons of the substantia nigra. 2002 Wiley Periodicals, Inc. J Neurobiol 52: 221,229, 2002 [source]

The G protein,coupled receptor G2A: Involvement in hepatic lipid metabolism and gallstone formation in mice,

HEPATOLOGY, Issue 4 2008
Laura E. Johnson
The G2A receptor is a member of the ovarian cancer G protein,coupled receptor 1 family of stress-inducible G protein,coupled receptors. In this study, we examined the hepatobiliary effects of loss of function of G2A in mice fed either a chow or lithogenic diet. G2A-deficient (G2A,/,) mice fed chow had a 25% reduction in biliary phosphatidylcholine content, reduced hepatic gene expression of the phosphatidylcholine transporter adenosine triphosphate,binding cassette B4, and an 8-fold increase in expression of the nuclear receptor liver X receptor (LXR). Despite the increased expression of LXR, transcription of several LXR target genes was reduced. G2A,/, mice fed a lithogenic diet had rapid gallstone formation, an increased cholesterol saturation index, a 2.5-fold increase in farnesoid X receptor expression, a 5-fold increase in LXR expression, and a 90% reduction in cholesterol 7,-hydroxylase expression in comparison with wild-type mice. There were no changes in gallbladder volume. Conclusion: These data demonstrate that the G2A receptor is important for hepatobiliary bile salt, cholesterol, and phospholipid homeostasis and for the pathogenesis of cholesterol gallstone formation. (HEPATOLOGY 2008;48:1138,1148.) [source]

HIF prolyl hydroxylase inhibition increases cell viability and potentiates dopamine release in dopaminergic cells

Jens Leander Johansen
J. Neurochem. (2010) 115, 209,219. Abstract Hypoxia-inducible factor (HIF) controls the expression of genes that adapts the cellular condition to accommodate oxidative stress. The potential beneficial effect of HIF up-regulation in ischemia has recently gained interest substantiated by the known HIF-regulation of erythropoietin and other hypoxia accommodating genes. So far the perspectives for HIF up-regulation has been focused on anemia and ischemia related diseases but little information is available about the relevance of HIF biology for neurodegenerative disease like Parkinson's disease. We therefore sought out to characterize the effect of HIF-up-regulation on survival and dopamine homeostasis in dopaminergic cells. We used a low molecular weight HIF prolyl hydroxylase (HPH) inhibitor and lentiviral based shRNA knockdown of HPH subtypes as molecular tools to increase HIF protein level and downstream HIF-regulated genes. We show that HIF induction results in protection against oxidative stress in cellular models based on PC12 cells and LUHMES cells. In addition, HPH inhibition elevates tyrosine hydroxylase expression and activity, which causes increased dopamine synthesis and release in both PC12 cells and a primary rat ventral mesencephalic cell culture. All together these findings suggest that prolyl hydroxylases may represent novel targets for therapeutic intervention in disorders characterized by dopamine homeostasis dysregulation like Parkinson's disease. [source]

5,-dihydrotestosterone inhibits 1,,25-dihydroxyvitamin D3 -induced expression of CYP24 in human prostate cancer cells

THE PROSTATE, Issue 3 2005
Yan-Ru Lou
Abstract BACKGROUND A cross-talk between 1,,25-dihydroxyvitamin D3 [1,,25-(OH)2D3] and 5,-dihydrotestosterone (DHT) in the growth inhibition has been demonstrated, but the mechanism is unknown. METHODS The expression of 25-hydroxyvitamin D3 24-hydroxylase (24-hydroxylase) was measured using a real-time quantitative RT-PCR assay and the catabolism of 1,,25-(OH)2D3 was measured using a radioreceptor assay. RESULTS Real-time RT-PCR showed that DHT at 1,100 nM significantly inhibited 1,,25-(OH)2D3 -induced expression of 24-hydroxylase in LNCaP cells. Furthermore, the catabolism of 1,,25-(OH)2D3 was decreased by 10 nM DHT. An androgen receptor (AR) antagonist, Casodex antagonized the DHT effect, whereas an AR agonist (due to the mutant AR in LNCaP cells) hydroxyflutamide did not. CONCLUSIONS We demonstrated, for the first time, that DHT reduces the ability of 1,,25-(OH)2D3 to induce 24-hydroxylase expression. Our results not only support the earlier finding of a cross-talk between androgen and vitamin D in human prostate cancer cells but also provide a possible mechanism how androgen and vitamin D signaling pathways may interact. 2004 Wiley-Liss, Inc. [source]