Publications by authors named "Sylvie Dufour"

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver disease globally. Disruptions in iron metabolism and mitochondrial oxidative function may cooperatively contribute to its pathogenesis. Ferredoxin reductase (FDXR), a mitochondrial flavoprotein, plays a critical role in mitochondrial respiratory supercomplex formation and iron-sulfur cluster biosynthesis-both essential for efficient oxidative metabolism.

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The most emblematic metamorphoses in the animal kingdom remain those of the caterpillar into a butterfly and the tadpole into a frog. However, some other vertebrates also present, at one or more steps of their biological cycle, drastic changes in their morphology, physiology and behavior, allowing them to adapt to a new environment (habitat) and way of life, and thus considered as metamorphoses. This is the case within fish, for some representatives of teleosts (the largest group among vertebrates) and of cyclostomes (the most ancient group among vertebrates).

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Metabolic reprograming has been linked to epithelial-to-mesenchymal transition (EMT) in cancer cells, but how it influences EMT in normal cells remains largely unknown. Here we explored how metabolism impacts delamination and migration of avian trunk neural crest cells, an important progenitor cell population of the vertebrate embryo. We report that delamination exhibits a quiescent metabolic phenotype whereas migration is characterized by OXPHOS-driven metabolism coupled to distinct expression of metabolic, EMT and developmental genes.

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Understanding the reproductive resiliency of scleractinian corals is imperative as ocean acidification and rising sea surface temperatures threaten the foundation of coral reef ecosystems. However, the limited temporal scales of laboratory and transplantation-based methods fail to consider evolutionary time frames offered by natural analogues of future climate conditions, like hydrothermal vents (HV). Accordingly, we characterized the presence of scleractinians surrounding a major shallow-water HV near Kueishan Island in northeastern Taiwan, identified a candidate species, Tubastraea aurea, and investigated its sexual reproductive strategies.

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Plastic pollution persists due to polymers' resistance to depolymerization, making eco-design and enzymatic recycling essential for sustainability. However, understanding plastic depolymerization is complex, and studies often separate enzymatic from non-enzymatic degradation, despite their interconnectedness in practice. This study aims to simplify this process, unifying key factors into a single mechanism using polylactide (PLA) as a model.

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Metabolic dysfunction-associated steatohepatitis (MASH) represents a progressive form of steatotic liver disease which increases the risk for fibrosis and advanced liver disease. The accumulation of discrete species of bioactive lipids has been postulated to activate signaling pathways that promote inflammation and fibrosis. However, the key pathogenic lipid species is a matter of debate.

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The pituitary glycoprotein hormones (GPHs) control several physiological processes in vertebrates such as reproduction and metabolism. They include the luteinizing hormone (LH), the follicle-stimulating hormone (FSH), and the thyroid-stimulating hormone (TSH), which activate their cognate leucine-rich repeat G protein-coupled receptors (LGRs), LHR, FSHR, and TSHR. Each GPH consists of a common α subunit and a specific βFSH, βLH or βTSH subunit.

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Hypothalamic gonadotropin-releasing hormone (GnRH) regulates the production of gonadotropins, which control reproduction. In elasmobranchs, unlike other gnathostomes, GnRH is released into the systemic circulation to stimulate gonadotrope cells located in the ventral lobe of the pituitary. The aim of this study was to investigate the potential role of systemic GnRH in the regulation of the testis in Scyliorhinus canicula.

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Background: In certain cephalopod species, two distinct symbiotic organs host large populations of microorganisms: the light organ, regulated by the daily cycle, and the accessory nidamental gland (ANG), regulated by the female reproductive cycle. While host-microbiota interactions in the light organ of the bobtail squid are well understood, the dynamics within the ANG remain largely unexplored. This study uses the bigfin reef squid, Sepioteuthis lessoniana, as a model to investigate the microbiomes associated with specific regions of the ANG, capitalizing on its relatively large gland size compared to the bobtail squid.

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Unlabelled: Metabolic dysfunction-associated steatohepatitis (MASH) represents a progressive form of steatotic liver disease which increases the risk for fibrosis and advanced liver disease. The accumulation of discrete species of bioactive lipids has been postulated to activate signaling pathways that promote inflammation and fibrosis. However, the key pathogenic lipid species is a matter of debate.

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Previous studies highlight the potential for sodium-glucose cotransporter type 2 (SGLT2) inhibitors (SGLT2i) to exert cardioprotective effects in heart failure by increasing plasma ketones and shifting myocardial fuel utilization toward ketone oxidation. However, SGLT2i have multiple in vivo effects and the differential impact of SGLT2i treatment and ketone supplementation on cardiac metabolism remains unclear. Here, using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) methodology combined with infusions of [13C6]glucose or [13C4]βOHB, we demonstrate that acute SGLT2 inhibition with dapagliflozin shifts relative rates of myocardial mitochondrial metabolism toward ketone oxidation, decreasing pyruvate oxidation with little effect on fatty acid oxidation in awake rats.

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Article Synopsis
  • - The hypothalamic-pituitary-gonadal (HPG) axis regulates reproduction in gnathostomes, involving gonadotropins like FSH and LH that interact with their specific receptors in gonads; however, research on these in chondrichthyes (sharks and rays) is limited.
  • - This study identified gonadotropin and receptor sequences in chondrichthyan genomes, analyzed their structures compared to humans, and built 3D interaction models, emphasizing the role of the receptor hinge for ligand recognition.
  • - Expression analysis showed that FSHR and LHR are active throughout spermatogenesis in various testicular cells, with high levels of FSHR transcripts in testis and
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Article Synopsis
  • * There was no significant difference in mitochondrial oxidation rates between the MASL/MASLD groups and controls, indicating that fatty liver conditions do not impair this process.
  • * An increase in plasma glucagon levels enhanced mitochondrial oxidation rates by 50%-75% in both groups and boosted glucose production by about 50% specifically in the MASL group, partially through increased mitochondrial activity.
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Eels are gonochoristic species whose gonadal differentiation initiates at the yellow eel stage and is influenced by environmental factors. We revealed some sex-related genes were sex dimorphically expressed in gonads during gonadal sex differentiation of Japanese eel (Anguilla japonica); however, the expression of sex-related genes in the brain-pituitary during gonadal sex differentiation in eels is still unclear. This study aimed to investigate the sex-related gene expressions in the brain-pituitary and tried to clarify their roles in the brain and gonads during gonadal sex differentiation.

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The first hematopoietic stem and progenitor cells (HSPCs) emerge in the Aorta-Gonad-Mesonephros (AGM) region of the mid-gestation mouse embryo. However, the precise nature of their supportive mesenchymal microenvironment remains largely unexplored. Here, we profiled transcriptomes of laser micro-dissected aortic tissues at three developmental stages and individual AGM cells.

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Article Synopsis
  • - The study focuses on how the brain-pituitary-testis axis influences male development and hinders female traits in black porgy fish, exploring the unclear feedback between gonadal hormones and brain signals.
  • - Experiments included short-term sex steroid treatments and surgical gonadectomy, revealing that male fish showed the highest levels of gths transcripts, while hormone treatments increased pituitary lhb transcripts.
  • - Findings suggest that exogenous sex steroids impact gths transcription related to gonadal development, and gonadectomy doesn’t significantly change brain signaling gene expression, indicating a communication link between the testis and brain for male fate management.
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Context: In clinical trials, burosumab ameliorates symptoms of pain, fatigue, and stiffness and improves performance on certain muscle function studies in patients with X-linked hypophosphatemia (XLH).

Objective: This work aimed to determine if burosumab increases adenosine triphosphate (ATP) synthesis in skeletal muscle of treatment-naive adults with XLH, and if so, whether that correlates with improved muscle function.

Methods: Ten untreated, symptomatic adults with XLH had ATP synthesis rates measured in the right calf using the 31P magnetic resonance spectroscopy saturation transfer technique.

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The PNPLA3 I148M variant is the major genetic risk factor for all stages of fatty liver disease, but the underlying pathophysiology remains unclear. We studied the effect of this variant on hepatic metabolism in homozygous carriers and non-carriers under multiple physiological conditions with state-of-the-art stable isotope techniques. After an overnight fast, carriers had higher plasma β-hydroxybutyrate concentrations and lower hepatic de novo lipogenesis (DNL) compared to non-carriers.

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Bioenergetic metabolism is a key regulator of cellular function and signaling, but how it can instruct the behavior of cells and their fate during embryonic development remains largely unknown. Here, we investigated the role of glucose metabolism in the development of avian trunk neural crest cells (NCCs), a migratory stem cell population of the vertebrate embryo. We uncovered that trunk NCCs display glucose oxidation as a prominent metabolic phenotype, in contrast to what is seen for cranial NCCs, which instead rely on aerobic glycolysis.

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The hydrothermal crab, Xenograpsus testudinatus (xtcrab) inhabits shallow-water, hydrogen sulfide (HS)-rich hydrothermal vent regions. Until now, the adaptative strategy of xtcrab to this toxic environment was unknown. Herein, we investigated the sulfide tolerance and detoxification mechanisms of xtcrabs collected in their high-sulfide hydrothermal vent habitat.

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In vertebrates, the tachykinin system includes tachykinin genes, which encode one or two peptides each, and tachykinin receptors. The complexity of this system is reinforced by the massive conservation of gene duplicates after the whole-genome duplication events that occurred in vertebrates and furthermore in teleosts. Added to this, the expression of the tachykinin system is more widespread than first thought, being found beyond the brain and gut.

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The transient receptor potential vanilloid (TRPV) ion channel family is involved in multiple sensory and physiological functions including thermosensing and temperature-dependent neuroendocrine regulation. The objective of the present study was to investigate the number, origin and evolution of TRPV genes in metazoans, with special focus on the impact of the vertebrate whole-genome duplications (WGD). Gene searches followed by phylogenetic and synteny analyses revealed multiple previously undescribed TRPV genes.

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Corticotropin-releasing hormone (CRH) was discovered for its role as a brain neurohormone controlling the corticotropic axis in vertebrates. An additional gene, , paralog of (), and likely resulting from the second round (2R) of vertebrate whole genome duplication (WGD), was identified in a holocephalan chondrichthyan, in basal mammals, various sauropsids and a non-teleost actinopterygian holostean. It was suggested that has been recurrently lost in some vertebrate groups including teleosts.

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BackgroundNonalcoholic fatty liver affects 25% to 30% of the US and European populations; is associated with insulin resistance (IR), type 2 diabetes, and increased cardiovascular risk; and is defined by hepatic triglyceride (HTG) content greater than 5.56%. However, it is unknown whether HTG content less than 5.

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Cadherins control intercellular adhesion in most metazoans. In vertebrates, intercellular adhesion differs considerably between cadherins of type-I and type-II, predominantly due to their different extracellular regions. Yet, intercellular adhesion critically depends on actomyosin contractility, in which the role of the cadherin extracellular region is unclear.

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