Biology subjects

Moulin, A.

Publications and source records attributed to Moulin, A..

7 recordsLinked to original sources

bioRxiv2025

Prevalence of hemic neoplasia in cockles and co-habiting bivalve species in the western coast of France and the southern coast of Portugal.

Hemic neoplasia is a cancer affecting several bivalve species and has become transmissible in some lineages. This study assesses its prevalence in common cockles (Cerastoderma edule) along the western coast of France and the southern coast of Portugal, regions with important bivalve fisheries. Cockles and cohabiting bivalve species (Ruditapes spp. and Scrobicularia plana) were sampled across multiple locations, and hemic neoplasia was diagnosed through cytological analysis. In the Algarve, a decline in prevalence was observed between 2017 and 2024, while in Normandy, the disease was detected for the first time. No cases of hemic neoplasia were found in the cohabiting clam species, suggesting that cockle cancer transmission may be species restricted. Morphometric analyses revealed no significant differences in size or weight between affected and non-affected cockles, indicating that external traits are not reliable indicators of infection. These findings expand knowledge on the geographic distribution of hemic neoplasia and highlight the need for continued monitoring to assess potential changes in its prevalence and impact on bivalve populations.

cancer biology↗

bioRxiv2024

Global and selective effects of auditory attention on arousal: insights from pupil dilation

Theoretical models of attention propose that norepinephrine (NE) can induce both a global boost of arousal and selective amplification of high-priority stimuli, yet few tasks have tested these dual effects in humans. Here, we used pupillometry in an auditory detection task, the Competitive Attention Test (CAT), previously performed in large cohort studies, to examine how task engagement (active vs. passive) and stimulus relevance (informative vs. uninformative cues) modulate arousal. Results showed that both relevant and irrelevant sounds elicited larger pupil dilation under active conditions, indicating a global arousal effect. Crucially, only relevant sounds benefited from an additional dilation when preceded by an informative cue, demonstrating a selective arousal mechanism associated to top-down attention. These findings illustrate the NEs dual role in boosting overall alertness while selectively enhancing high-priority stimuli. Beyond theoretical implications, this work highlights that the CAT captures measurable arousal components, reinforcing its utility for clinical assessments of attention-arousal clinical disruptions.

neuroscience↗

bioRxiv2024

Glutamylation imbalance leads to photoreceptor degeneration

The stereotypic structure of microtubules, assembled from conserved /{beta}-tubulin dimers is subject to a complex diversity of Post-translational Modifications (PTMs). PTMs are predicted to fine-tune microtubule properties and interactions with other proteins, thus allowing microtubules to perform specific functions. Cilia accumulate several types of tubulin PTMs, such as polyglutamylation, polyglycylation, detyrosination and acetylation, whose functions are not yet fully understood. Recently, mutations of AGBL5, coding for the deglutamylating enzyme CCP5, have been associated to retinitis pigmentosa, suggesting that perturbation of polyglutamylation leads to the degeneration of photoreceptor cells. However, the molecular mechanisms underlying this degeneration remain unknown. Here, using super-resolution Ultrastructure Expansion Microscopy in mouse and human photoreceptor cells, we found that most tubulin PTMs are accumulated at the level of the connecting cilium, a structure linking the outer and inner segments of photoreceptor cells. Using mouse models with increased glutamylation (Ccp5-/- and Ccp1-/-), or loss of tubulin acetylation (Atat1-/-), we demonstrated that aberrant glutamylation, but not loss of acetylation, resulted in perturbed molecular architecture of the outer segment, with the loss of the bulge region and destabilization of the distal axoneme. Concurrently, we observed a substantial impairment in tubulin glycylation and intraflagellar transport. Altogether our results indicate that glutamylation plays a crucial role in the maintenance of the molecular architecture of the outer segment and point to tubulin PTM imbalance as possible culprit in retinal degeneration.

cell biology↗

bioRxiv2024

Generation of systemic rabbit chimeras via Induced Pluripotent Stem Cells Reprogrammed with KLF2, ERAS, and PRMT6

Little is known about the molecular underpinnings of pluripotent stem cells (PSCs) ability to colonize the epiblast of preimplantation embryos and generate chimeras. In our study, using rabbit PSCs as a model system, we conducted unbiased screening of a cDNA library that encodes a panel of 36 pluripotency factors. From this screening, we identified KLF2, ERAS and PRMT6, whose overexpression confers the ability for self-renewal in a KOSR/FGF2-free culture medium supplemented with LIF, activin A, PKC and WNT inhibitors. The reprogrammed cells acquired transcriptomic and epigenetic features of naive pluripotency, including the reactivation of the 2nd X-chromosome. Leveraging these PSC lines, we determined the transcriptomic signature of embryonic colonization-competence, demonstrating transcriptional repression of genes involved in MAPK, WNT, HIPPO, and EPH signaling pathways, alongside the activation of genes involved in amino-acid metabolism, NF-kB signaling, and p53 pathway. Remarkably, a subset of reprogrammed cells, expressing CD75 at a high level, gained the ability to produce chimeric fetuses with a high contribution from PSCs in all lineages.

cell biology↗

bioRxiv2023

Role of the prefrontal cortex in musical and verbal short-term memory: A functional near-infrared spectroscopy study

Auditory short-term memory (STM) is a key process in auditory cognition, with evidence for partly distinct networks subtending musical and verbal STM. The delayed matching-to-sample task (DMST) paradigm has been found suitable for comparing musical and verbal STM and for manipulating memory load. In this study, musical and verbal DMSTs were investigated with measures of activity in frontal areas with functional near-infrared spectroscopy (fNIRS): Experiment 1 compared musical and verbal DMSTs with a low-level perception task (that does not entail encoding, retention, or retrieval of information), to identify frontal regions involved in memory processes. Experiment 2 manipulated memory load for musical and verbal materials to uncover frontal brain regions showing parametric changes in activity with load and their potential differences between musical and verbal materials. A FIR model was used to deconvolute fNIRS signals across successive trials without making assumptions with respect to the shape of the hemodynamic response in a DMST. Results revealed the involvement of the dorso-lateral prefrontal cortex (dlPFC) and inferior frontal gyri (IFG), but not of the superior frontal gyri (SFG) in both experiments, in keeping with previously reported neuroimaging data (including fMRI). Experiment 2 demonstrated a parametric variation of activity with memory load in bilateral IFGs during the maintenance period, with opposite directions for musical and verbal materials. Activity in the IFGs increased with memory load for verbal sound sequences, in keeping with previous results with n-back tasks. The decreased activity with memory load observed with musical sequences is discussed in relation to previous research on auditory STM rehearsal strategies. This study highlights fNIRS as a promising tool for investigating musical and verbal STM not only for typical populations, but also for populations with developmental language disorders associated with functional alterations in auditory STM.

neuroscience↗

bioRxiv2021

Transcriptomic, epigenetic and metabolic characterization of the pluripotency continuum in rabbit preimplantation embryos

Despite the growing interest in the rabbit model for developmental and stem cell biology, the characterization of embryos at the molecular level is still poorly documented. We conducted a transcriptome analysis of rabbit pre-implantation embryos from E2.7 (morula stage) to E6.6 (early primitive streak stage) using bulk and single-cell RNA-sequencing. In parallel, we studied oxidative phosphorylation and glycolysis and analysed active and repressive epigenetic modifications during blastocyst formation and expansion. We generated a transcriptomic, epigenetic, and metabolic map of the pluripotency continuum in rabbit preimplantation embryos and identified novel markers of naive pluripotency that might be instrumental for deriving naive pluripotent stem cell lines. Although the rabbit is evolutionarily closer to mice than to primates, we found that the transcriptome of rabbit epiblast cells shares common features with that of humans and non-human primates. Summary StatementRabbit preimplantation embryos share characteristics with human and monkey embryos with respect to timing of early lineage segregation and expression of marker genes for naive and primed pluripotency.

developmental biology↗

bioRxiv2020

Primate naive pluripotent stem cells stall in the G1 phase of the cell cycle and differentiate prematurely during embryo colonization

After reprogramming to naive pluripotency, human pluripotent stem cells (PSCs) still exhibit very low ability to make interspecies chimeras. Whether this is because they are inherently devoid of the attributes of chimeric competency or because naive PSCs cannot colonize embryos from distant species remains to be elucidated. Here, we have used different types of mouse, human and rhesus monkey naive PSCs and analyzed their ability to colonize rabbit and cynomolgus monkey embryos. Mouse embryonic stem cells (ESCs) remained mitotically active and efficiently colonized host embryos. In contrast, primate naive PSCs colonized host embryos with much lower efficiency. Unlike mouse ESCs, they slowed DNA replication after dissociation and, after injection into host embryos, they stalled in the G1 phase and differentiated prematurely, regardless of host species. We conclude that human and non-human primate naive PSCs do not efficiently make chimeras because they are inherently unfit to remain mitotically active during colonization.

cell biology↗