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Geoffroy Mallaret

@gmallaret.bsky.social
75 followers 128 following 29 posts

Ph.D. Gut Brain Microbiome axis, microbiology, behavior, neurosciences, infections 💩🦠🧠🐀. Postdoctoral fellow at Pasteur Institute. orcid: orcid.org/0000-0002-3658-3418

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Geoffroy Mallaret @gmallaret.bsky.social · 29/09/2026
I am very pleased to see our latest study published on the implication of p-cresol in constipation associated with ASD. A huge thank-you to the entire team and especially Narjis Kraimi, David Fabregat Safont, Oscar J Pozo and Laetitia Davidovic. Hope you enjoy it! www.nature.com/articles/s41...
nature.com
Microbial metabolite p-cresol associates with constipation in adults with high-functioning autism spectrum disorder and induces constipation-like symptoms in mice - Scientific Reports
Scientific Reports - Microbial metabolite p-cresol associates with constipation in adults with high-functioning autism spectrum disorder and induces constipation-like symptoms in mice
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Reposted by Geoffroy Mallaret
Inserm @inserm.fr · 15/06/2026
Une équipe de l’Inserm a mis au point une méthode de culture permettant de produire, pour la première fois, des organoïdes intestinaux humains fonctionnels de grande taille, et ce deux fois plus rapidement qu’avec les méthodes existantes. Lire le communiqué : presse.inserm.fr/des-scientif...
presse.inserm.fr
Des scientifiques parviennent à créer des organoïdes intestinaux plus grands et dotés d’un système nerveux fonctionnel - Salle de presse de l'Inserm
De plus en plus de personnes souffrent de maladies gastro-intestinales. Pour mieux comprendre ces pathologies et apporter des solutions aux patients, les scientifiques travaillent sur les organoïdes, ...
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Geoffroy Mallaret @gmallaret.bsky.social · 05/02/2026
www.nature.com/collections/...
nature.com
Brain and Body Communication in Health and Disease
In this cross-journal Collection we invite submissions of basic, pre-clinical, and clinical studies focusing on the bidirectional communication between the ...
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Geoffroy Mallaret @gmallaret.bsky.social · 22/01/2026
www.nature.com/articles/s41...
nature.com
Baby-to-baby strain transmission shapes the developing gut microbiome - Nature
A metagenomic survey of babies attending the first year of nursery detected extensive baby-to-baby microbial strain transmission, pointing to social interactions in infancy as crucial drivers of infan...
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Reposted by Geoffroy Mallaret
Marnix Medema @marnixmedema.bsky.social · 13/12/2025
Now available online: the new 2.0 version of gutSMASH, with capabilities to detect 12 new types of catabolic gene clusters relevant to gut microbiome ecology, as well as predictions of their regulation through transcription factor binding site detection. www.sciencedirect.com/science/arti...
sciencedirect.com
gutSMASH 2.0: Extended Identification of Primary Metabolic Gene Clusters From the Human Gut Microbiota
Microbiota-derived metabolites serve as key messengers mediating host–microbe and microbe–microbe interactions, often through specialized primary meta…
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Reposted by Geoffroy Mallaret
mara lawniczak @marakat.bsky.social · 03/12/2025
please share this postdoc job alert! come join the budding Biodiversity Cell Atlas initiative as a postdoc or senior postdoc at @sangerinstitute.bsky.social working closely with @arnausebe.bsky.social and me to make progress on what we cover in this paper www.nature.com/articles/s41...
nature.com
The Biodiversity Cell Atlas: mapping the tree of life at cellular resolution - Nature
The Biodiversity Cell Atlas aims to create comprehensive single-cell molecular atlases across the eukaryotic tree of life, which will be phylogenetically informed, rely on high-quality genomes and use...
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Reposted by Geoffroy Mallaret
Karsten Suhre @ksuhre.bsky.social · 04/12/2025
Faecal metabolites as a readout of habitual diet capture dietary interactions with the gut microbiome. By integrating faecal metabolomics, metagenomics, and dietary data Falchi et al. show that faecal metabolites capture mediations between diet and the gut microbiome www.nature.com/articles/s41...
nature.com
Faecal metabolites as a readout of habitual diet capture dietary interactions with the gut microbiome - Nature Communications
Here, by integrating faecal metabolomics, metagenomics, and habitual dietary data of two large human cohorts, the authors show that faecal metabolites reflect diet and gut microbiome interactions, pre...
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Reposted by Geoffroy Mallaret
Aleksandra Deczkowska @adeczkowska.bsky.social · 03/12/2025
Excited to share our new preprint: “Local B cell maturation and mast cell regulation of choroid plexus function in early life” www.biorxiv.org/content/10.1... , initiated in the lab by Laetitia Travier and led by the one and only @fakesamir.bsky.social
biorxiv.org
Local B cell maturation and mast cell regulation of choroid plexus function in early life.
Postnatal development is a critical period for the maturation of the nervous and immune systems. The choroid plexus (CP) within the brain ventricles guides brain development through the production of ...
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Reposted by Geoffroy Mallaret
Nature Reviews Microbiology @natrevmicro.nature.com · 21/11/2025
ICYMI: New online! The gut microbiome shapes social behaviour across animal species
nature.com
The gut microbiome shapes social behaviour across animal species
Nature Reviews Microbiology, Published online: 14 November 2025; doi:10.1038/s41579-025-01262-yThe gut microbiome can influence brain activity and complex behaviours. In this Review, Griffiths et al. discuss microbiome-associated effects on social behaviour in laboratory model organisms, free-living animals and humans, and consider potential mechanistic pathways.
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David Fabregat @davidfabregat.bsky.social · 25/11/2025
📜It has been a pleasure to collaborate in this highly interesting study published in @commsbio.nature.com! 🎉Congrats @gmallaret.bsky.social and colleagues! 🔜And more to come from the collaboration bewteen Laetitia Davidovic's research group and Applied Metabolomics at @researchmar.bsky.social.
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Geoffroy Mallaret @gmallaret.bsky.social · 22/11/2025
Thrilled to share our recent research with Laetitia Davidovic, investigating how p-cresol contributes to social deficits by modulating host catecholamine-biosynthesizing enzymes. A huge thank-you to the entire team for their exceptional work. Hope you enjoy it! www.nature.com/articles/s42...
nature.com
The autism-linked gut microbial metabolite p-cresol inhibits host catecholamine biosynthesizing enzymes to elicit social deficits - Communications Biology
The microbial metabolite p-cresol and p-cresol sulfate accumulate in brainstem and inhibit TH and DBH, key enzymes in catecholamine synthesis. This disruption alters brain function and behavior, ...
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Geoffroy Mallaret @gmallaret.bsky.social · 22/11/2025
👸💀👸 www.cell.com/current-biol...
cell.com
Socially parasitic ant queens chemically induce queen-matricide in host workers
Taku Shimada and colleagues show that socially parasitic queens of two ant species spray their respective host queens with chemical signals that trigger host workers to kill the resident queen.
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Geoffroy Mallaret @gmallaret.bsky.social · 18/11/2025
Triste d'apprendre la disparition de Philippe Taquet. L'empreinte des dinosaures restera pour moi un de mes livres de paléontologie favoris. 😢
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Geoffroy Mallaret @gmallaret.bsky.social · 23/10/2025
www.biorxiv.org/content/10.1...
biorxiv.org
Induction of menstruation in mice reveals the regulation of menstrual shedding
During menstruation, an inner layer of the endometrium is selectively shed, while an outer, progenitor-containing layer is preserved to support repeated regeneration. Progress in understanding this co...
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Geoffroy Mallaret @gmallaret.bsky.social · 19/06/2025
Unlocking the power of human milk and infant feeding: Understanding how nutrition and early microbiota interaction shapes health programming 👶🍼🤱🦠🔬 www.cell.com/cell-host-mi...
cell.com
Unlocking the power of human milk and infant feeding: Understanding how nutrition and early microbiota interaction shapes health programming
Infant feeding plays a crucial role in microbial colonization, immune maturation, and development. Human milk is a bioactive system comprising biologics that shape the infant gut microbiome and suppor...
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Geoffroy Mallaret @gmallaret.bsky.social · 17/06/2025
Adaptive radiation and social evolution of the ants 🐜🐜🐜 www.cell.com/cell/fulltex...
cell.com
Adaptive radiation and social evolution of the ants
Comparative analyses of 163 ant genomes reveal extensive genome rearrangements, context-specific gene family expansion patterns, and selection on conserved pathways that together underpin the evolutio...
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Geoffroy Mallaret @gmallaret.bsky.social · 23/05/2025
royalsocietypublishing.org/doi/10.1098/...
royalsocietypublishing.org
Gut microbiota diversity affects fish behaviour and is influenced by host genetics and early rearing conditions | Open Biology
The gut microbiota influences human and animal cognition and behaviour through its effects on the endocrine and immune systems. The microbiome–behaviour relationship may be especially relevant for fish, due to their diverse evolutionary history and ...
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Geoffroy Mallaret @gmallaret.bsky.social · 22/05/2025
www.nature.com/articles/s41...
nature.com
The origin of vertebrate teeth and evolution of sensory exoskeletons - Nature
Re-examination of the presumed Cambrian fossil fish Anatolepis reveals previous misidentification of aglaspidid sensory structures as dentine, a vertebrate sensory tissue, showing it to be a...
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Geoffroy Mallaret @gmallaret.bsky.social · 19/05/2025
www.cell.com/current-biol...
cell.com
Dominance rank inference in mice via chemosensation
Borak et al. reveal that male mice can infer the dominance status of unfamiliar opponents using scalable chemosensory cues. Sensory ablation experiments demonstrate that both olfactory and vomeronasal...
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Geoffroy Mallaret @gmallaret.bsky.social · 16/04/2025
I am pleased to share our new study about the perinatal involvement of the microbial metabolite p-cresol in neurodevelopmental disorders. Enjoy :) www.nature.com/articles/s41...
nature.com
Perinatal exposure to the autism-linked metabolite p-Cresol has limited impact on early development in mice but lasting effects on adult social behavior - Scientific Reports
Scientific Reports - Perinatal exposure to the autism-linked metabolite p-Cresol has limited impact on early development in mice but lasting effects on adult social behavior
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Geoffroy Mallaret @gmallaret.bsky.social · 05/03/2025
www.nature.com/articles/s41...
nature.com
Sensory input, sex and function shape hypothalamic cell type development - Nature
Paired transcriptomic and chromatin accessibility profiling are used to examine the developmental trajectories of neuronal populations in the hypothalamic preoptic region, including cell types with ke...
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Reposted by Geoffroy Mallaret
Catherine Dulac @dulaclab.bsky.social · 05/03/2025
After last week publication from the lab on circuits of social isolation/satiety, today we publish a different line of research by @harriskaplan.bsky.social et al., on the development trajectories of hypothalamic POA cell types driving survival and social behavior. www.nature.com/articles/s41...
nature.com
Sensory input, sex and function shape hypothalamic cell type development - Nature
Paired transcriptomic and chromatin accessibility profiling are used to examine the developmental trajectories of neuronal populations in the hypothalamic preoptic region, including cell types with ke...
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Geoffroy Mallaret @gmallaret.bsky.social · 26/02/2025
www.nature.com/articles/s41...
nature.com
A hypothalamic circuit underlying the dynamic control of social homeostasis - Nature
New data on brain-wide circuits centred around two interconnected hypothalamic neuron populations provide significant mechanistic insights into the emergence of social need during social isolation and...
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Geoffroy Mallaret @gmallaret.bsky.social · 26/02/2025
www.cell.com/neuron/abstr...
cell.com
Dietary availability acutely influences puberty onset via a hypothalamic neural circuit
Goto et al. measure the pulsatile activity of the reproductive center in the hypothalamic arcuate nucleus during puberty in female mice. They discover that food availability rapidly and bidirectionall...
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Reposted by Geoffroy Mallaret
Richard Lenski @relenski.bsky.social · 24/02/2025
Happy 37th birthday to the LTEE! the-ltee.org/history/
the-ltee.org
History – The Long-Term Evolution Experiment
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Geoffroy Mallaret @gmallaret.bsky.social · 15/02/2025
Evidence for Endogenous Collagen in Edmontosaurus Fossil Bone 🦕🦖🧪🔬 pubs.acs.org/doi/10.1021/...
pubs.acs.org
Evidence for Endogenous Collagen in Edmontosaurus Fossil Bone
Reports of proteins in fossilized bones have been a subject of controversy in the scientific literature because it is assumed that fossilization results in the destruction of all organic components. In this paper, a novel combination of analytical techniques is used to address this question for an exceptionally well-preserved Edmontosaurus sacrum excavated from the Upper Cretaceous strata of the South Dakota Hell Creek Formation. Cross-polarized light microscopy (XPol) shows birefringence consistent with collagen presence. Tandem LC-MS unambiguously identified, and for the first time quantified, hydroxyproline, a unique collagen-indicator amino acid, in acid-digested samples from the Edmontosaurus. LC-MS/MS bottom-up proteomics shows identical collagen peptide sequences previously identified and reported for another hadrosaur and a T. rex sample.
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Laure Bindels @laurebindels.bsky.social · 13/01/2025
🎉New article from our team demonstating that a #microbiota derived #bileacid improves hepatic #cholesterol levels in mice with cancer #cachexia! Congratulations to Morgane Thibaut & Martin Roumain! Thanks to our collaborators, the FNRS and the @welbio.bsky.social www.tandfonline.com/doi/full/10....
tandfonline.com
The microbiota-derived bile acid taurodeoxycholic acid improves hepatic cholesterol levels in mice with cancer cachexia
Alterations in bile acid profile and pathways contribute to hepatic inflammation in cancer cachexia, a syndrome worsening the prognosis of cancer patients. As the gut microbiota impinges on host me...
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Geoffroy Mallaret @gmallaret.bsky.social · 09/01/2025
Self-experience of a negative event alters responses to others in similar states through prefrontal cortex CRF mechanisms www.nature.com/articles/s41...
nature.com
Self-experience of a negative event alters responses to others in similar states through prefrontal cortex CRF mechanisms - Nature Neuroscience
Maltese et al. show in mice that experiencing an adverse event affects future interaction with others experiencing the same stressor. These self-experience socioemotional reactions are orchestrated by...
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Reposted by Geoffroy Mallaret
François Leulier @francoisleulier.bsky.social · 03/01/2025
PGN is such a phenomenal intra- and inter-kingdom signalling molecule! #MicroSky #MicrobiomeSky
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Geoffroy Mallaret @gmallaret.bsky.social · 02/01/2025
Roseburia intestinalis-derived butyrate alleviates neuropathic pain www.cell.com/cell-host-mi...
cell.com
Roseburia intestinalis-derived butyrate alleviates neuropathic pain
Jiang et al. identified distinct gut microbiota profiles in healthy individuals and patients with shingles or postherpetic neuralgia (PHN). They developed a metagenomics-based model to assess PHN risk and showed that Roseburia intestinalis produces butyrate to alleviate pain by activating vagal nerves, suppressing pain-related brain regions in animal models.
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Geoffroy Mallaret @gmallaret.bsky.social · 30/12/2024
Gut-derived IL-13 contributes to growth via promoting hepatic IGF-1 production microbiomejournal.biomedcentral.com/articles/10....
microbiomejournal.biomedcentral.com
Gut-derived IL-13 contributes to growth via promoting hepatic IGF-1 production - Microbiome
Background The gut microbiota has a profound effect on immunity and metabolic status of the host, which has increasingly attracted research communities. However, the intrinsic mechanism underlying the...
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Geoffroy Mallaret @gmallaret.bsky.social · 30/12/2024
Metformin decelerates aging clock in male monkeys www.sciencedirect.com/science/arti...
sciencedirect.com
Metformin decelerates aging clock in male monkeys
In a rigorous 40-month study, we evaluated the geroprotective effects of metformin on adult male cynomolgus monkeys, addressing a gap in primate aging…
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Geoffroy Mallaret @gmallaret.bsky.social · 27/12/2024
www.cell.com/cell-metabol... glucagon-like peptide 1 receptor activation inhibits Toll-like receptor agonist-induced inflammation
cell.com
Central glucagon-like peptide 1 receptor activation inhibits Toll-like receptor agonist-induced inflammation
GLP-1R agonists may reduce cardiometabolic complications in part through reduction of inflammation. Here we show, using pharmacology and genetics, that the anti-inflammatory actions of GLP-1RAs to reduce TLR-mediated inflammation require CNS GLP-1R signaling.
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Geoffroy Mallaret @gmallaret.bsky.social · 23/12/2024
www.cell.com/cell-metabol...
cell.com
Acute and circadian feedforward regulation of agouti-related peptide hunger neurons
Douglass et al. employ long-term, continuous fiber photometry to uncover new modes of agouti-related peptide (AgRP) neuron regulation in ad libitum, fasted, and circadian conditions. AgRP neuron activity exhibits a circadian rhythm, which controls daily feeding patterns through a neural circuit from the suprachiasmatic nucleus via the dorsomedial hypothalamus.
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Reposted by Geoffroy Mallaret
Filipe De Vadder @filipedevadder.bsky.social · 03/12/2024
My first paper as a PI is out today. Hopefully more to come soon! Congratulations @ameliejoly.bsky.social and colleagues!
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Geoffroy Mallaret @gmallaret.bsky.social · 07/12/2024
Elevated IL-22 as a result of stress-induced gut leakage suppresses septal neuron activation to ameliorate anxiety-like behavior www.cell.com/immunity/ful...
cell.com
Elevated IL-22 as a result of stress-induced gut leakage suppresses septal neuron activation to ameliorate anxiety-like behavior
Immune activation is often thought to exacerbate stress-related mental disorders. Here, Xia, Lu, Lan, et al. reveal elevated IL-22 derived from the gut during the early phase of repeated stress. IL-22 suppresses neuron activation in the brain and mitigates stress-induced anxiety, suggesting an immune defense mechanism against psychological insults.
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Reposted by Geoffroy Mallaret
François Leulier @francoisleulier.bsky.social · 06/12/2024
Drosophila and Lactiplantibacillus plantarum in the spotlight (again), what a wonderful model (disclaimer I am biased ;-) ). Congrats Will and team! www.science.org/doi/10.1126/...
science.org
A conserved bacterial genetic basis for commensal-host specificity
Animals selectively acquire specific symbiotic gut bacteria from their environments that aid host fitness. To colonize, a symbiont must locate its niche and sustain growth within the gut. Adhesins are...
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Reposted by Geoffroy Mallaret
Amélie Joly @ameliejoly.bsky.social · 03/12/2024
🚨🥳The first part of my PhD is out in Nutrition & Metabolism! We show that moderate protein restriction combined with high fat triggers metabolic dysfunction without obesity in juvenile mice. If you want to know more about it, check out the paper👇 link-springer-com.insb.bib.cnrs.fr/epdf/10.1186...
link-springer-com.insb.bib.cnrs.fr
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Geoffroy Mallaret @gmallaret.bsky.social · 23/11/2024
Really interesting Hierarchical eco-evo dynamics mediated by the gut microbiome www.cell.com/trends/ecolo...
cell.com
Hierarchical eco-evo dynamics mediated by the gut microbiome
The concept of eco-evolutionary (eco-evo) dynamics, stating that ecological and evolutionary processes occur at similar time scales and influence each other, has contributed to our understanding of re...
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Geoffroy Mallaret @gmallaret.bsky.social · 23/11/2024
🤩 www.science.org/doi/10.1126/...
science.org
The disciplinary matrix of holobiont biology
Uniting life’s seen and unseen realms guides a conceptual advance in research
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Geoffroy Mallaret @gmallaret.bsky.social · 20/11/2024
Exposure to sugar rationing in the first 1000 days of life protected against chronic disease www.science.org/doi/10.1126/...
science.org
Exposure to sugar rationing in the first 1000 days of life protected against chronic disease
We examined the impact of sugar exposure within 1000 days since conception on diabetes and hypertension, leveraging quasi-experimental variation from the end of the United Kingdom’s sugar rationing in...
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Reposted by Geoffroy Mallaret
John F. Cryan @jfcryan.bsky.social · 05/11/2024
Gut microbiota regulates stress responsivity via the circadian system - our latest paper just out - well done Gabriel Tofani & all www.cell.com/cell-metabol...
cell.com
Gut microbiota regulates stress responsivity via the circadian system
Gut microbes are known to modulate stress responsivity and behavior. Tofani et al. demonstrate that such modulations occur via the circadian system. The oscillations in gut microbiota composition regu...
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