| 1. |
- Adlanmerini, M., et al.
(author)
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Mutation of Arginine 264 on ER alpha (Estrogen Receptor Alpha) Selectively Abrogates the Rapid Signaling of Estradiol in the Endothelium Without Altering Fertility
- 2020
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In: Arteriosclerosis, Thrombosis, and Vascular Biology. - : Ovid Technologies (Wolters Kluwer Health). - 1079-5642 .- 1524-4636. ; 40:9, s. 2143-2158
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Journal article (peer-reviewed)abstract
- Objective: ER alpha (estrogen receptor alpha) exerts nuclear genomic actions and also rapid membrane-initiated steroid signaling. The mutation of the cysteine 451 into alanine in vivo has recently revealed the key role of this ER alpha palmitoylation site on some vasculoprotective actions of 17 beta-estradiol (E2) and fertility. Here, we studied the in vivo role of the arginine 260 of ER alpha which has also been described to be involved in its E2-induced rapid signaling with PI-3K (phosphoinositide 3-kinase) as well as G protein in cultured cell lines. Approach and Results: We generated a mouse model harboring a point mutation of the murine counterpart of this arginine into alanine (R264A-ER alpha). In contrast to theC451A-ER alpha, theR264A-ER alpha females are fertile with standard hormonal serum levels and normal control of hypothalamus-pituitary ovarian axis. Although R264A-ER alpha protein abundance was normal, the well-described membrane ER alpha-dependent actions of estradiol, such as the rapid dilation of mesenteric arteries and the acceleration of endothelial repair of carotid, were abrogated inR264A-ER alpha mice. In striking contrast, E2-regulated gene expression was highly preserved in the uterus and the aorta, revealing intact nuclear/genomic actions in response to E2. Consistently, 2 recognized nuclear ER alpha-dependent actions of E2, namely atheroma prevention and flow-mediated arterial remodeling were totally preserved. Conclusions: These data underline the exquisite role of arginine 264 of ER alpha for endothelial membrane-initiated steroid signaling effects of E2 but not for nuclear/genomic actions. This provides the first model of fertile mouse with no overt endocrine abnormalities with specific loss-of-function of rapid ER alpha signaling in vascular functions.
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| 2. |
- Fontaine, C., et al.
(author)
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The tissue-specific effects of different 17 beta-estradiol doses reveal the key sensitizing role of AF1 domain in ER alpha activity
- 2020
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In: Molecular and Cellular Endocrinology. - : Elsevier BV. - 0303-7207. ; 505
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Journal article (peer-reviewed)abstract
- 17 beta-Estradiol (E2) action can be mediated by the full-length estrogen receptor alpha (ER alpha 66), and also by the AF1 domain-deficient ER alpha (ER alpha 46) isoform, but their respective sensitivity to E2 is essentially unknown. We first performed a dose response study using subcutaneous home-made pellets mimicking either metestrus, proestrus or a pharmacological doses of E2, which resulted in plasma concentrations around 3, 30 and 600 pM, respectively. Analysis of the uterus, vagina and bone after chronic exposure to E2 demonstrated dose-dependent effects, with a maximal response reached at the proestrus-dose in wild type mice expressing mainly ER alpha 66. In contrast, in transgenic mice harbouring only an ER alpha deleted in AF1, these effects of E2 were either strongly shifted rightward (10-100-fold) and/or attenuated, depending on the tissue studied. Finally, experiments in different cell lines transfected with ER alpha 66 or ER alpha 46 also delineated varying profiles of ER alpha AF1 sensitivity to E2. Altogether, this work emphasizes the importance of dose in the tissue-specific actions of E2 and demonstrates the key sensitizing role of AF1 in ER alpha activity.
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| 3. |
- Smati, S., et al.
(author)
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Integrative study of diet-induced mouse models of NAFLD identifies PPARα as a sexually dimorphic drug target
- 2022
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In: Gut. - : BMJ Publishing Group. - 0017-5749 .- 1468-3288. ; 71:4, s. 807-821
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Journal article (peer-reviewed)abstract
- We evaluated the influence of sex on the pathophysiology of non-alcoholic fatty liver disease (NAFLD). We investigated diet-induced phenotypic responses to define sex-specific regulation between healthy liver and NAFLD to identify influential pathways in different preclinical murine models and their relevance in humans. Different models of diet-induced NAFLD (high-fat diet, choline-deficient high-fat diet, Western diet or Western diet supplemented with fructose and glucose in drinking water) were compared with a control diet in male and female mice. We performed metabolic phenotyping, including plasma biochemistry and liver histology, untargeted large-scale approaches (liver metabolome, lipidome and transcriptome), gene expression profiling and network analysis to identify sex-specific pathways in the mouse liver. The different diets induced sex-specific responses that illustrated an increased susceptibility to NAFLD in male mice. The most severe lipid accumulation and inflammation/fibrosis occurred in males receiving the high-fat diet and Western diet, respectively. Sex-biased hepatic gene signatures were identified for these different dietary challenges. The peroxisome proliferator-activated receptor α (PPARα) co-expression network was identified as sexually dimorphic, and in vivo experiments in mice demonstrated that hepatocyte PPARα determines a sex-specific response to fasting and treatment with pemafibrate, a selective PPARα agonist. Liver molecular signatures in humans also provided evidence of sexually dimorphic gene expression profiles and the sex-specific co-expression network for PPARα. These findings underscore the sex specificity of NAFLD pathophysiology in preclinical studies and identify PPARα as a pivotal, sexually dimorphic, pharmacological target. NCT02390232.
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| 4. |
- Vinel, A., et al.
(author)
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Role of ERalpha in the Effect of Estradiol on Cancellous and Cortical Femoral Bone in Growing Female Mice
- 2016
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In: Endocrinology. - : The Endocrine Society. - 0013-7227 .- 1945-7170. ; 157:6, s. 2533-2544
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Journal article (peer-reviewed)abstract
- Estrogen receptor-alpha (ER alpha) acts primarily in the nucleus as a transcription factor involving two activation functions, AF1 and AF2, but it can also induce membrane-initiated steroid signaling (MISS) through the modulation of various kinase activities and/or secondary messenger levels. Previous work has demonstrated that nuclear ER alpha is required for the protective effect of the estrogen 17 beta-estradiol (E2), whereas the selective activation of ER alpha MISS is sufficient to confer protection in cortical but not cancellous bone. The aim of this study was to define whether ER alpha MISS is necessary for the beneficial actions of chronic E2 exposure on bone. We used a mouse model in which ER alpha membrane localization had been abrogated due to a point mutation of the palmitoylation site of ER alpha (ER alpha-C451A). Alterations of the sex hormones in ER alpha-C451A precluded the interpretation of bone parameters that were thus analyzed on ovariectomized and supplemented or not with E2 (8 mu g/kg/d) to circumvent this bias. We found the beneficial action of E2 on femoral bone mineral density as well as in both cortical and cancellous bone was decreased in ER alpha-C451A mice compared with their wild-type littermates. Histological and biochemical approaches concurred with the results from bone marrow chimeras to demonstrate that ER alpha MISS signaling affects the osteoblast but not the osteoclast lineage in response to E2. Thus, in contrast to the uterine and endothelial effects of E2 that are specifically mediated by nuclear ER alpha and ER alpha MISS effects, respectively, bone protection is dependent on both, underlining the exquisite tissue-specific actions and interactions of membrane and nuclear ER alpha.
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| 5. |
- Frandsen, K. E. H., et al.
(author)
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The molecular basis of polysaccharide cleavage by lytic polysaccharide monooxygenases
- 2016
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In: Nature Chemical Biology. - : Springer Science and Business Media LLC. - 1552-4450 .- 1552-4469. ; 12:4, s. 298-
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Journal article (peer-reviewed)abstract
- Lytic polysaccharide monooxygenases (LPMOs) are copper-containing enzymes that oxidatively break down recalcitrant polysaccharides such as cellulose and chitin. Since their discovery, LPMOs have become integral factors in the industrial utilization of biomass, especially in the sustainable generation of cellulosic bioethanol. We report here a structural determination of an LPMO-oligosaccharide complex, yielding detailed insights into the mechanism of action of these enzymes. Using a combination of structure and electron paramagnetic resonance spectroscopy, we reveal the means by which LPMOs interact with saccharide substrates. We further uncover electronic and structural features of the enzyme active site, showing how LPMOs orchestrate the reaction of oxygen with polysaccharide chains.
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| 6. |
- Montandon, A. J., et al.
(author)
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A new strategy for carrier and prenatal diagnosis and molecular studies in haemophilia B
- 1991
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In: Biotechnology of Plasma Proteins : Haemostasis, Thrombosis and Iron Proteins International Symposium, Florence, April 1990 - Haemostasis, Thrombosis and Iron Proteins International Symposium, Florence, April 1990. - : S. Karger AG. - 9783805552509 - 9783318035285 ; 58, s. 88-93
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Conference paper (peer-reviewed)
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