Membrane-associated estrogen receptor and caveolin-1 are present in central nervous system myelin and oligodendrocyte plasma membranes

2004 ◽  
Vol 75 (5) ◽  
pp. 603-613 ◽  
Author(s):  
Dina N. Arvanitis ◽  
Huimin Wang ◽  
Richard D. Bagshaw ◽  
John W. Callahan ◽  
Joan M. Boggs
1999 ◽  
Vol 144 (2) ◽  
pp. 373-384 ◽  
Author(s):  
Ann T.J. Beliën ◽  
Paolo A. Paganetti ◽  
Martin E. Schwab

Invasive glioma cells migrate preferentially along central nervous system (CNS) white matter fiber tracts irrespective of the fact that CNS myelin contains proteins that inhibit cell migration and neurite outgrowth. Previous work has demonstrated that to migrate on a myelin substrate and to overcome its inhibitory effect, rat C6 and human glioblastoma cells require a membrane-bound metalloproteolytic activity (C6-MP) which shares several biochemical and pharmacological characteristics with MT1-MMP. We show now that MT1-MMP is expressed on the surface of rat C6 glioblastoma cells and is coenriched with C6-MP activity. Immunodepletion of C6-MP activity is achieved with an anti–MT1-MMP antibody. These data suggest that MT1-MMP and the C6-MP are closely related or identical. When mouse 3T3 fibroblasts were transfected with MT1-MMP they acquired the ability to spread and migrate on the nonpermissive myelin substrate and to infiltrate into adult rat optic nerve explants. MT1-MMP–transfected fibroblasts and C6 glioma cells were able to digest bNI-220, one of the most potent CNS myelin inhibitory proteins. Plasma membranes of both MT1-MMP–transfected fibroblasts and C6 glioma cells inactivated inhibitory myelin extracts, and this activity was sensitive to the same protease inhibitors. Interestingly, pretreatment of CNS myelin with gelatinase A/MMP-2 could not inactivate its inhibitory property. These data imply an important role of MT1-MMP in spreading and migration of glioma cells on white matter constituents in vitro and point to a function of MT1-MMP in the invasive behavior of malignant gliomas in the CNS in vivo.


1994 ◽  
Vol 47 (11) ◽  
pp. 1989 ◽  
Author(s):  
GB Barlin ◽  
LP Davies ◽  
PW Harrison ◽  
NW Jacobsen ◽  
AC Willis

Some 6-( chloro, alkylthio, phenylthio, benzylthio or pyridinylmethylthio )-3-( unsubstituted , benzamidomethyl or methoxy )-2-styrylimidazo[1,2-b] pyridazines and 6-chloro-3-( unsubstituted and benzamidomethyl )-2-benzoylimidazo[1,2-b] pyridazines have been prepared and tested for their ability to displace [3H]diazepam from rat brain plasma membranes. The structures of 6-chloro-2-benzoyl[and 6-fluoro-2-(4′-tolyl)] imidazo [1,2-b] pyridazine have been confirmed by X-ray analyses. The reactions of 6-methylthio(and 6-phenylthio)pyridazin-3-amines with 3-bromo-1-phenylpropane-1,2-dione also have been investigated. The 6-substituted 3-unsubstituted 2-styryl(and benzoyl ) imidazo [1,2-b] pyridazines did not bind strongly to rat brain benzodiazepine receptors; nor did the 3-benzamidomethyl or 3-methoxy derivatives (cf. the 2-phenyl analogues). However, 3-benzamidomethyl-6-(pyridin-3-ylmethylthio)-2-styrylimidazo[1,2-b] pyridazine was an exception with IC50 68 nM.


1989 ◽  
Vol 42 (10) ◽  
pp. 1735 ◽  
Author(s):  
GB Barlin ◽  
LP Davies ◽  
SJ Ireland ◽  
MML Ngu

Series of 6-( alkoxy - and methylthio-phenoxy )-2-phenyl(substituted phenyl and pyridiny1)imidazo[l,2-b]pyridazines and 3-methoxy-6-( methoxybenzylthio )-2-phenyl(substituted phenyl and pyridinyl ) imidazo[l,2-b]pyridazines have been prepared and subsequently tested for their ability to inhibit GABA-stimulated 3H-diazepam binding to rat brain plasma membranes. The 6( alkoxy- and methylthio-phenoxy ) and 6-( methoxybenzylthio) compounds were much more effective in the displacement studies than the parent 6-phenoxy or 6-benzylthio compounds respectively. 3-Methoxy-6-(2′-methoxyphenoxy)-2-phenylimidazo[l,2-b]pyridazine (GBLD-167, IC50 70 nm) was 16 times more effective than its 3-methoxy-6-phenoxy analogue (GBLD-163, IC50 1120 nM ) and the 3-methoxy-6-(21-methoxybenzylthio)-2-phenyl compound (GELD-214, 1C50 9 nM ) was two and a half times more active than its 6-benzylthio-3-methoxy analogue (GBLD-137, IC50 22 nM ). The most active member of the 6-phenoxy series was the 2-(41-fluorophenyl)-3-methoxy-6- (2″-methoxyphenoxy) compound (GBLD-255, IC50 30 nM ) and, within the 6-benzylthio series, the 2-(4′-fluorophenyl, 3′-aminophenyl, and pyridin-31-yl)-3-methoxy-6-(3″-methoxybenzylthio) compounds (GBLD-233, 301 and 296) all gave IC50 5 nM. A Hansch -type analysis of the results for these two closely related series of compounds indicates that electron-donating substituents in 2-(para substituted phenyl) derivatives favour binding, but bulky substituents hinder this effect.


2008 ◽  
Vol 7 (6) ◽  
pp. 7290.2008.00027 ◽  
Author(s):  
Alessia Stell ◽  
Silvia Belcredito ◽  
Paolo Ciana ◽  
Adriana Maggi

Estrogen receptors have long been known to be expressed in several brain areas in addition to those directly involved in the control of reproductive functions. Investigations in humans and in animal models suggest a strong influence of estrogens on limbic and motor functions, yet the complexity and heterogeneity of neural tissue have limited our approaches to the full understanding of estrogen activity in the central nervous system. The aim of this study was to examine the transcriptional activity of estrogen receptors in the brain of male and female mice. Exploiting the ERE-Luc reporter mouse, we set up a novel, bioluminescence-based technique to study brain estrogen receptor transcriptional activity. Here we show, for the first time, that estrogen receptors are similarly active in male and female brains and that the estrous cycle affects estrogen receptor activity in regions of the central nervous system not known to be associated with reproductive functions. Because of its reproducibility and sensitivity, this novel bioluminescence application stands as a candidate as an innovative methodology for the study and development of drugs targeting brain estrogen receptors.


1988 ◽  
Vol 41 (8) ◽  
pp. 1149 ◽  
Author(s):  
GB Barlin ◽  
LP Davies ◽  
MML Ngu

The synthesis of a series of 6-chloro-3-methoxy(and ethoxy )-2- phenyl[and (variously substituted phenyl), thienyl, and naphthalenyl ] imidazo [1,2-b] pyridazines and a 6-fluoro analogue are reported. These compounds were tested for their ability to displace [3H]diazepam bound to washed rat brain plasma membranes. Under standard assay conditions (see Experimental) and in the presence of 100 μM γ- aminobutyric acid, 6-chloro-3-methoxy-2-(p-tolyl ) imidazo [1,2- b] pyridazine was the most active compound with an IC50 value of 148 nM (cf. diazepam, with IC50 of 4.2 nM).


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