Polycystic ovary syndrome (PCOS) is characterized by an oligo-anovulation, hyperandrogenism and polycystic ovarian morphology combined with major metabolic disturbances. However, despite the high ...prevalence and the human and economic consequences of this syndrome, its etiology remains unknown. In this study, we show that female Goto-Kakizaki (GK) rats, a type 2 diabetes mellitus model, encapsulate naturally all the reproductive and metabolic hallmarks of lean women with PCOS at puberty and in adulthood. The analysis of their gestation and of their fetuses demonstrates that this PCOS-like phenotype is developmentally programmed. GK rats also develop features of ovarian hyperstimulation syndrome. Lastly, a comparison between GK rats and a cohort of women with PCOS reveals a similar reproductive signature. Thus, this spontaneous rodent model of PCOS represents an original tool for the identification of the mechanisms involved in its pathogenesis and for the development of novel strategies for its treatment.
Huntington's disease is an autosomal dominant neurodegenerative disease caused by abnormal polyglutamine expansion in huntingtin (Exp-HTT) leading to degeneration of striatal neurons. Altered brain ...cholesterol homeostasis has been implicated in Huntington's disease, with increased accumulation of cholesterol in striatal neurons yet reduced levels of cholesterol metabolic precursors. To elucidate these two seemingly opposing dysregulations, we investigated the expression of cholesterol 24-hydroxylase (CYP46A1), the neuronal-specific and rate-limiting enzyme for cholesterol conversion to 24S-hydroxycholesterol (24S-OHC). CYP46A1 protein levels were decreased in the putamen, but not cerebral cortex samples, of post-mortem Huntington's disease patients when compared to controls. Cyp46A1 mRNA and CYP46A1 protein levels were also decreased in the striatum of the R6/2 Huntington's disease mouse model and in SThdhQ111 cell lines. In vivo, in a wild-type context, knocking down CYP46A1 expression in the striatum, via an adeno-associated virus-mediated delivery of selective shCYP46A1, reproduced the Huntington's disease phenotype, with spontaneous striatal neuron degeneration and motor deficits, as assessed by rotarod. In vitro, CYP46A1 restoration protected SThdhQ111 and Exp-HTT-expressing striatal neurons in culture from cell death. In the R6/2 Huntington's disease mouse model, adeno-associated virus-mediated delivery of CYP46A1 into the striatum decreased neuronal atrophy, decreased the number, intensity level and size of Exp-HTT aggregates and improved motor deficits, as assessed by rotarod and clasping behavioural tests. Adeno-associated virus-CYP46A1 infection in R6/2 mice also restored levels of cholesterol and lanosterol and increased levels of desmosterol. In vitro, lanosterol and desmosterol were found to protect striatal neurons expressing Exp-HTT from death. We conclude that restoring CYP46A1 activity in the striatum promises a new therapeutic approach in Huntington's disease.
Spinocerebellar ataxias (SCAs) are devastating neurodegenerative disorders for which no curative or preventive therapies are available. Deregulation of brain cholesterol metabolism and impaired brain ...cholesterol turnover have been associated with several neurodegenerative diseases. SCA3 or Machado–Joseph disease (MJD) is the most prevalent ataxia worldwide. We show that cholesterol 24-hydroxylase (CYP46A1), the key enzyme allowing efflux of brain cholesterol and activating brain cholesterol turnover, is decreased in cerebellar extracts from SCA3 patients and SCA3 mice. We investigated whether reinstating CYP46A1 expression would improve the disease phenotype of SCA3 mouse models. We show that administration of adeno-associated viral vectors encoding CYP46A1 to a lentiviral-based SCA3 mouse model reduces mutant ataxin-3 accumulation, which is a hallmark of SCA3, and preserves neuronal markers. In a transgenic SCA3 model with a severe motor phenotype we confirm that cerebellar delivery of AAVrh10-CYP46A1 is strongly neuroprotective in adult mice with established pathology. CYP46A1 significantly decreases ataxin-3 protein aggregation, alleviates motor impairments and improves SCA3-associated neuropathology. In particular, improvement in Purkinje cell number and reduction of cerebellar atrophy are observed in AAVrh10-CYP46A1-treated mice. Conversely, we show that knocking-down CYP46A1 in normal mouse brain impairs cholesterol metabolism, induces motor deficits and produces strong neurodegeneration with impairment of the endosomal–lysosomal pathway, a phenotype closely resembling that of SCA3. Remarkably, we demonstrate for the first time both in vitro, in a SCA3 cellular model, and in vivo, in mouse brain, that CYP46A1 activates autophagy, which is impaired in SCA3, leading to decreased mutant ataxin-3 deposition. More broadly, we show that the beneficial effect of CYP46A1 is also observed with mutant ataxin-2 aggregates. Altogether, our results confirm a pivotal role for CYP46A1 and brain cholesterol metabolism in neuronal function, pointing to a key contribution of the neuronal cholesterol pathway in mechanisms mediating clearance of aggregate-prone proteins. This study identifies CYP46A1 as a relevant therapeutic target not only for SCA3 but also for other SCAs.
•Amino acid analysis in plasma is of utmost importance in human medicine•Actual methods of amino acid analysis are very time consuming or not specific or not robust•HPLC-MS/MS using a mixed-mode ...stationary phase avoids pre column derivatization of amino acids•HPLC-MS/MS using a mixed-mode stationary phase avoids ion pairing reagent adding to amino acids
Here we describe a new HPLC–MS/MS method using a mixed mode stationary phase and a binary gradient of elution for the rapid separation and quantification of AAs in human plasma without derivatization or ion pairing reagent addition. The sample preparation procedure consists in a single dilution step after protein precipitation with sulfosalicylic acid. The proposed method allows for the unambiguous identification and analysis of 52 AAs and related compounds including the separation of isomers and isobars in an 18 min chromatographic run including the conditioning and the equilibration times. AAs were detected by selective reaction monitoring. Internal calibration was used for the quantification of 37 AAs, including 25 using the corresponding isotopically labeled internal standards. External calibration (no internal standard) was used for five additional analytes. Qualitative detection was achieved for the remaining compounds.
Validation studies evaluated accuracy, linearity, within- and between-run precision, lower limits of detection and quantification for 37 amino acids present in commonly used quality control samples. For within-run precision CVs averaged 3.8 % (n = 30) for all compounds. For between-run precision, CVs averaged 8.6 % for all compounds (n = 20). Correlation with the common standard ion-exchange chromatography with post-column derivatization method was also performed for 32 plasma samples. While the proposed method is at least 50 times more sensitive, the data showed good correlation with slopes equal or higher than 0.9 and correlation coefficients mostly higher than 0.90. The method was successfully applied for analysis of plasma samples for detection of inherited disorders of amino acid metabolism.
•A LC-MS/MS quantitative method was developed for tryptophan and 20 tryptophan-related metabolites.•References values were determined in healthy human serum and stool samples.•A proof of concept ...study with IBD patients was performed to validate the method.•Significant variations of tryptophan metabolites between control and IBD patients.
Tryptophan, an essential amino acid, and its metabolites are involved in many physiological processes including neuronal functions, immune system, and gut homeostasis. Alterations to tryptophan metabolism are associated with various pathologies such as neurologic, psychiatric disorders, inflammatory bowel diseases (IBD), metabolic disorders, and cancer. It is consequently critical to develop a reliable, quantitative method for the analysis of tryptophan and its downstream metabolites from the kynurenine, serotonin, and indoles pathways. An LC-MS/MS method was designed for the analysis of tryptophan and 20 of its metabolites, without derivatization and performed in a single run. This method was validated for both serum and stool. The comparisons between serum and plasma, collected with several differing anticoagulants, showed significant differences only for serotonin. References values were established in sera and stools from healthy donors. For stool samples, as a proof of concept, the developed method was applied to a healthy control group and an IBD patient group. Results showed significant differences in the concentrations of tryptophan, xanthurenic acid, kynurenic acid, indole-3-lactic acid, and picolinic acid. This method allowed an extensive analysis of the three tryptophan metabolic pathways in two compartments. Beyond the application to IBD patients, the clinical use of this method is wide-ranging and may be applied to other pathological conditions involving tryptophan metabolism, such as neurological, psychiatric, or auto-inflammatory pathologies.
We aimed to develop and evaluate a machine learning model that can stratify infertile/fertile couples on the basis of their bioclinical signature helping the management of couples with unexplained ...infertility. Fertile and infertile couples were recruited in the ALIFERT cross-sectional case-control multicentric study between September 2009 and December 2013 (NCT01093378). The study group consisted of 97 infertile couples presenting a primary idiopathic infertility (> 12 months) from 4 French infertility centers compared with 100 fertile couples (with a spontaneously conceived child (< 2 years of age) and with time to pregnancy < 12 months) recruited from the healthy population of the areas around the infertility centers. The study group is comprised of 2 independent sets: a development set (n = 136 from 3 centers) serving to train the model and a test set (n = 61 from 1 center) used to provide an unbiased validation of the model. Our results have shown that: (i) a couple-modeling approach was more discriminant than models in which men's and women's parameters are considered separately; (ii) the most discriminating variables were anthropometric, or related to the metabolic and oxidative status; (iii) a refined model capable to stratify fertile vs. infertile couples with accuracy 73.8% was proposed after the variables selection (from 80 to 13). These influential factors (anthropometric, antioxidative, and metabolic signatures) are all modifiable by the couple lifestyle. The model proposed takes place in the management of couples with idiopathic infertility, for whom the decision-making tools are scarce. Prospective interventional studies are now needed to validate the model clinical use.Trial registration: NCT01093378 ALIFERT https://clinicaltrials.gov/ct2/show/NCT01093378?term=ALIFERT&rank=1 . Registered: March 25, 2010.
Aims/hypothesis
Exosomes released from cells can transfer both functional proteins and RNAs between cells. In this study we tested the hypothesis that muscle cells might transmit specific signals ...during lipid-induced insulin resistance through the exosomal route.
Methods
Exosomes were collected from quadriceps muscles of C57Bl/6 mice fed for 16 weeks with either a standard chow diet (SD) or an SD enriched with 20% palm oil (HP) and from C2C12 cells exposed to 0.5 mmol/l palmitate (EXO-Post Palm), oleate (EXO-Post Oleate) or BSA (EXO-Post BSA).
Results
HP-fed mice were obese and insulin resistant and had altered insulin-induced Akt phosphorylation in skeletal muscle (SkM). They also had reduced expression of
Myod1
and
Myog
and increased levels of
Ccnd1
mRNA, indicating that palm oil had a deep impact on SkM homeostasis in addition to insulin resistance. HP-fed mouse SkM secreted more exosomes than SD-fed mouse SkM. This was reproduced in-vitro using C2C12 cells pre-treated with palmitate, the most abundant saturated fatty acid of palm oil. Exosomes from HP-fed mice, EXO-Post Palm and EXO-Post Oleate induced myoblast proliferation and modified the expressions of genes involved in the cell cycle and muscle differentiation but did not alter insulin-induced Akt phosphorylation. Lipidomic analyses showed that exosomes from palmitate-treated cells were enriched in palmitate, indicating that exosomes likely transfer the deleterious effect of palm oil between muscle cells by transferring lipids. Muscle exosomes were incorporated into various tissues in vivo, including the pancreas and liver, suggesting that SkM could transfer specific signals through the exosomal route to key metabolic tissues.
Conclusions/interpretation
Exosomes act as ‘paracrine-like’ signals and modify muscle homeostasis during high-fat diets.
Widely used for their anti-inflammatory and immunosuppressive properties, glucocorticoids are nonetheless responsible for the development of diabetes and lipodystrophy. Despite an increasing number ...of studies focused on the adipocyte glucocorticoid receptor (GR), its precise role in the molecular mechanisms of these complications has not been elucidated. In keeping with this goal, we generated a conditional adipocyte-specific murine model of GR invalidation (AdipoGR knockout KO mice). Interestingly, when administered a corticosterone treatment to mimic hypercorticism conditions, AdipoGR-KO mice exhibited an improved glucose tolerance and insulin sensitivity. This was related to the adipose-specific activation of the insulin-signaling pathway, which contributed to fat mass expansion, as well as a shift toward an anti-inflammatory macrophage polarization in adipose tissue of AdipoGR-KO animals. Moreover, these mice were protected against ectopic lipid accumulation in the liver and displayed an improved lipid profile, contributing to their overall healthier phenotype. Altogether, our results indicate that adipocyte GR is a key factor of adipose tissue expansion and glucose and lipid metabolism control, which should be taken into account in the further design of adipocyte GR-selective modulators.
Annexin A2 (AnxA2) is a calcium- and phospholipid-binding protein that plays roles in cellular processes involving membrane and cytoskeleton dynamics and is able to associate to several partner ...proteins. However, the principal molecular partners of AnxA2 are negatively charged phospholipids such as phosphatidylserine and phosphatidyl-inositol-(4,5)-phosphate. Herein we have studied different aspects of membrane lipid rearrangements induced by AnxA2 membrane binding. X-ray diffraction data revealed that AnxA2 has the property to stabilize lamellar structures and to block the formation of highly curved lipid phases (inverted hexagonal phase, HII). By using pyrene-labelled cholesterol and the environmental probe di-4-ANEPPDHQ, we observed that in model membranes, AnxA2 is able to modify both, cholesterol distribution and lipid compaction. In epithelial cells, we observed that AnxA2 localizes to membranes of different lipid order. The protein binding to membranes resulted in both, increases and/or decreases in membrane order depending on the cellular membrane regions. Overall, AnxA2 showed the capacity to modulate plasma membrane properties by inducing lipid redistribution that may lead to an increase in order or disorder of the membranes.
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•AnnexinA2 reduces phospholipid curved structures and stabilizes lamellar organization.•AnnexinA2 binding to membranes induces cholesterol redistribution.•AnxA2 and di-4-ANEPPDHQ co-labelling reveals protein-membrane domain preferences.•AnnexinA2 is able to increase and/or decrease plasma membrane order.
Composite lipid emulsions containing soybean oil (30%), medium-chain triglycerides (30%), olive oil (25%), and fish oil (15%) (SMOF) are now widely used.
We aimed to evaluate the tolerance, the ...efficiency, and the erythrocyte fatty acid (FA) profile for children on long-term home parenteral nutrition (HPN) receiving a composite fish oil–based emulsion (FOLE).
At baseline, children (n = 46) with severe intestinal failure highly dependent on parenteral nutrition (PN) for ≥1 y were included in the study when they had received the composite FOLE for >6 mo. Out of this baseline group, only 25 children remained highly PN-dependent (SMOF1, n = 25) and could be assessed a second time, 2.4 y later (SMOF2, n = 25). An independent control group (“weaned off PN” group; n = 24) included children who had been weaned off PN for >2 y (median: 4 y). RBC-FA composition was established by GC-MS. Growth parameters, plasma citrulline, conjugated bilirubin, FA profiles, and the Holman ratio (20:3ω-9/20:4ω-6) were compared between groups.
No difference for growth parameters, citrulline, and bilirubin was observed between the SMOF groups after 2.4 y (0.2 <P < 0.8). The weaned-off group did not differ from the SMOF groups for growth parameters (0.2 <P < 0.4) but citrulline was higher (P < 0.0001) and conjugated bilirubin lower (P < 0.01). The composite FOLE induced higher proportions of EPA (20:5n–3) (8.4% ± 2.9%) and DHA (22:6n–3) (11.7% ± 2.2%) than what was observed in weaned-off children (0.8% ± 0.4% and 6.6% ± 2.3%, respectively) but lower proportions of arachidonic acid (20:4n–6). However, the Holman ratio did not vary between groups (P = 0.9), whereas the PUFA concentrations varied widely.
Long-term use of the composite FOLE was well tolerated in HPN-dependent children. The RBC-FA profile alterations were consistent with the ω-3 PUFA–enriched composition of this emulsion without evidence of essential FA deficiency.
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