Biology subjects

Dumas, E.

Publications and source records attributed to Dumas, E..

4 recordsLinked to original sources

bioRxiv2026

Recurrent neuronal loops between medial prefrontal cortex and ventral tegmental area display sex-specific spatial reorganization in response to stress

The medial prefrontal cortex (mPFC) and ventral tegmental area (VTA) form a highly interconnected circuit involved in emotional regulation, stress reactivity, and cognitive processing. While prior research has established the anatomical and functional interactions between these regions, the precise organization and molecular identity of VTA neurons involved in unidirectional and bidirectional mPFC connectivity remains poorly defined, particularly under stress. We combined dual anterograde and retrograde viral tracing in male and female mice to label VTA neurons according to their connectivity with the mPFC. This approach identified three distinct subpopulations including mPFC-projecting, mPFC-receiving, and bidirectionally-connected neurons which accounted for nearly half of the labelled VTA population. Each group displayed molecular heterogeneity, with most cells expressing dopaminergic (TH) and glutamatergic (VGLUT2) transcripts rather than single dopaminergic or GABAergic (GAD1) markers. Acute and chronic stress exposure revealed sex- and circuit-specific patterns of c-Fos activation. In males, acute and chronic stress generated opposing rostrocaudally organized activation profiles, whereas females showed a more uniform increase in activity. Spatial clustering analyses further revealed that stress induces distinct hotspot organization within the VTA, with chronic stress promoting cohesive hotspot organization and consistent local enrichment of bidirectionally connected neurons despite a limited global activation. Together, these findings uncover a molecularly diverse mPFC-VTA circuitry with bidirectional connectivity that undergoes sex-dependent spatial and functional rearrangement under stress, providing new insights on circuit-level mechanisms of stress-related disorders.

neuroscience↗

bioRxiv2023

GDF15 mediates inflammation-associated bone loss through a brain-bone axis

Metabolic mediators play an important role in regulating chronic inflammation in the body. Here we report an unexpected role for GDF15 (Growth Differentiation Factor 15), a central mediator of food intake, in inflammation-associated bone loss. GDF15 serum levels were found to be elevated in arthritis patients and inversely correlated with bone density. Despite being associated with inflammation, we found that GDF15 itself does not cause, nor contribute to, clinical or histopathological arthritis. Rather, under inflammatory conditions, GDF15 mediates trabecular bone loss through its receptor GFRAL, which is exclusively expressed in the hindbrain. GDF15-GFRAL binding results in {beta}-adrenergic activation of MALPs (Marrow Adipocytic Lineage Precursors) in the bone marrow, which stimulate osteoclasts and trigger bone loss. These data suggest a metabolic mediator-controlled brain-bone axis in inflammation, through which bone loss is induced in a contextual rather than general manner. These findings may lead to more specific therapeutic interventions to protect bone.

immunology↗

bioRxiv2023

Sterile triggers drive joint inflammation in TNF and IL-1beta dependent mouse arthritis models

Arthritis is the most common extra-intestinal complication in inflammatory bowel disease (IBD). Conversely, arthritis patients are at risk for developing IBD and often display subclinical gut inflammation. These observations suggest a shared disease etiology, commonly termed the gut-joint-axis. The clinical association between gut and joint inflammation is further supported by the success of common therapeutic strategies and microbiota dysbiosis in both conditions. Most data however support a correlative relationship between gut & joint inflammation, while causative evidence is lacking. Using two independent transgenic mouse arthritis models, either TNF or IL1{beta} dependent, we demonstrate that arthritis develops independently of the microbiota and intestinal inflammation, since both lines develop full-blown articular inflammation under germ-free conditions. In contrast, TNF-driven gut inflammation is fully rescued in germ-free conditions indicating that the microbiota is driving TNF-induced gut inflammation. Together, our study demonstrates that, although common inflammatory pathways may drive both gut and joint inflammation, the molecular triggers initiating such pathways are distinct in these tissues.

immunology↗

bioRxiv2018

Independent domestication events in the blue-cheese fungus Penicillium roqueforti

Domestication provides an excellent framework for studying adaptive divergence. Using population genomics and phenotypic assays, we reconstructed the domestication history of the blue cheese mold Penicillium roqueforti. We showed that this fungus was domesticated twice independently. The population used in Roquefort originated from an old domestication event associated with weak bottlenecks and exhibited traits beneficial for pre-industrial cheese production (slower growth in cheese and greater spore production on bread, the traditional multiplication medium). The other cheese population originated more recently from the selection of a single clonal lineage, was associated to all types of blue cheese worldwide but Roquefort, and displayed phenotypes more suited for industrial cheese production (high lipolytic activity, efficient cheese cavity colonization ability and salt tolerance). We detected genomic regions affected by recent positive selection and putative horizontal gene transfers. This study sheds light on the processes of rapid adaptation and raises questions about genetic resource conservation.

evolutionary biology↗