Biology subjects

Loubat, A.

Publications and source records attributed to Loubat, A..

7 recordsLinked to original sources

bioRxiv2026

Vitality capacity preservation through lifelong aerobic exercise: a pathway to healthy ageing

BackgroundThe distinction between healthy and pathological ageing has led to the concept of vitality capacity (VC), which can be understood as the bodys physiological reserve. An individuals VC can be estimated using 12 biomarkers spread across 3 domains: immune and stress response, energy and metabolism and neuromuscular function. Vitality capacity may be preserved by lifelong physical activity. This cross-sectional study aimed to examine the relationship between lifelong aerobic physical activity and VC. MethodsVC of 20 lifelong active and 19 inactive healthy adults aged >55 years was assessed using 12 biomarkers across the three VC domains. Domain-specific z-scores were calculated and averaged to derive a global VC score. Principal component analysis was performed and loadings extracted to estimate domains weight, and multiple correlations were conducted to identify associations among biomarkers, domains and VC scores. ResultsVC was higher in lifelong active participants (+0.2 z-score units, p = 0.006) and correlated with age (r = -0.53, p < 0.001). Neuromuscular domain contributed most to VC variability, and the immune and stress response domain was higher in the active group (+0.4 z-score units, p = 0.001) as energy/metabolism among female participants (+0.5 z-score units, p.adj = 0.006). ConclusionLifelong aerobic physical activity is associated with higher VC in older adults, particularly within the immune and stress response domain. These findings highlight the role of physical activity in preserving the physiological reserve and reinforce the relevance of lifelong aerobic physical activity as a driver of healthy ageing.

physiology↗

bioRxiv2025

Environment and physiology shape antiphage system expression

Bacteria and archaea encode on average ten antiphage systems. Quorum sensing, cellular, or transcription factors can regulate specific systems (CRISPR-Cas, CBASS). Yet, a systematic assessment of antiphage systems expression patterns is lacking. Here, we combine publicly available RNA-seq data from 14 different species with an original RNA-seq dataset of 15 Escherichia coli strains across six environmental conditions and two growth stages. Using this data, we explore the transcription patterns of 236 antiphage systems from 81 types. Defense system expression is variable along environmental, physiological, as well as spatial gradients, and can correlate with cellular physiology and mobile genetic element activity. We identify antiphage systems as cohesive but complex transcriptional units, find coordinated expression of defense islands possibly underpinned by local regulators, and demonstrate the functional relevance of differential expression in native systems. Together, these results suggest that environmental and physiological factors regulate prokaryotic immunity and may prime bacteria for infection.

microbiology↗

bioRxiv2024

Unravelling the conundrum of nucleolar NR2F1 localization: A comparative analysis of NR2F1 antibody-based approaches in vitro and in vivo.

As a transcription factor, NR2F1 regulates spatiotemporal gene expression during development and in adulthood. Aberrant NR2F1 causes a rare neurodevelopmental disorder known as Bosch-Boonstra- Schaaf Optic Atrophy Syndrome. In addition, altered NR2F1 expression is frequently observed in various cancers and is considered a prognostic marker or potential therapeutic target. In this context, NR2F1 has been shown to localize not only in the nucleus but also in the nucleoli, suggesting a novel non-canonical role in this compartment. Hence, we studied this phenomenon employing various in vitro and in vivo models in different antibody-dependent approaches. Examination of seven commonly used anti-NR2F1 antibodies in different human cancer and stem cells as well as in wild type and null mice revealed that the nucleolar localization of NR2F1 is artificial and does not play a functional role. Our subsequent comparative analysis demonstrated for the first time which anti-NR2F1 antibody best fits which approach. As our data allow for correct data interpretation, making them publicly available may have far-reaching implications for NR2F1 research in health and disease. More generally, the study also underlines the need to optimize any antibody-mediated technique.

cell biology↗

bioRxiv2023

FGF8-mediated gene regulation affects regional identity in human cerebral organoids

The morphogen FGF8 establishes graded positional cues imparting regional cellular responses via modulation of early target genes. The roles of FGF signaling and its effector genes remain poorly characterized in human experimental models mimicking early fetal telencephalic development. We used hiPSC-derived cerebral organoids as an in vitro platform to challenge the effect of FGF8 signaling on neural identity and differentiation. We found that FGF8 treatment increases cellular heterogeneity leading to distinct telencephalic and mesencephalic-like domains that co-develop in multi-regional organoids. Within telencephalic domains, FGF8 affects the anteroposterior and dorsoventral identity of neural progenitors, the balance between GABAergic and glutamatergic neurons, thus impacting spontaneous neuronal network activity. Moreover, FGF8 efficiently modulates key regulators responsible for several human neurodevelopmental disorders. Overall, our results show that FGF8 signaling is directly involved in both regional patterning and cellular diversity in human cerebral organoids and in modulating genes associated with normal and pathological neural development.

developmental biology↗

bioRxiv2023

MAFB drives differentiation by permitting WT1 binding to podocyte 1 specific promoters

Podocytes are highly specialized cells, but their chromatin status and the precise molecular events leading to their differentiation remain poorly defined. Here we used ChIP-Seq analysis for H3K4me3, H3K4me1 and H3K27me3 to establish the histone methylation map in adult mouse podocytes. Our data demonstrate open chromatin across podocyte specific genes and reveals that genes expressed in the mesoderm lineage become actively repressed upon podocyte differentiation. To better understand the transcriptional control of podocyte differentiation, we studied the role of transcription factor MAFB. ChIP-Seq experiments and functional analysis in conditional knockout mice identified a set of direct MAFB targets including Nphs1, Nphs2, Vegfa and Tcf21. Loss of MafB led to the deposition of extracellular matrix, progressive foot process effacement, and kidney disease. ChIP experiments in knockout animals revealed that during development MAFB is essential for H3K4me3 methylation and the recruitment of WT1 to the promoters of the podocyte specific genes Nphs1 and Nphs2. Taken together our data reveal the crucial function of MAFB by permitting chromatin accessibility at podocyte-specific genes during development and maintaining terminal differentiation in adults.

developmental biology↗

bioRxiv2019

Chemoinformatic-guided engineering of polyketide synthases

Polyketide synthase (PKS) engineering is an attractive method to generate new molecules such as commodity, fine and specialty chemicals. A significant challenge in PKS design is engineering a partially reductive module to produce a saturated {beta}-carbon through a reductive loop exchange. In this work, we sought to establish that chemoinformatics, a field traditionally used in drug discovery, could provide a viable strategy to reductive loop exchanges. We first introduced a set of donor reductive loops of diverse genetic origin and chemical substrate structures into the first extension module of the lipomycin PKS (LipPKS1). Product titers of these engineered unimodular PKSs correlated with atom pair chemical similarity between the substrate of the donor reductive loops and recipient LipPKS1, reaching a titer of 165 mg/L of short chain fatty acids produced by Streptomyces albus J1074 harboring these engineered PKSs. Expanding this method to larger intermediates requiring bimodular communication, we introduced reductive loops of divergent chemosimilarity into LipPKS2 and determined triketide lactone production. Collectively, we observed a statistically significant correlation between atom pair chemosimilarity and production, establishing a new chemoinformatic method that may aid in the engineering of PKSs to produce desired, unnatural products.

biochemistry↗

bioRxiv2018

Morphofunctional deficits in the cerebral cortex of NeuroD2 mutant mice are associated with autism/schizophrenia-like behaviors

We identified seven families associating NEUROD2 pathogenic mutations with ASD and intellectual disability. To get insight into the pathophysiological mechanisms, we analyzed cortical development in Neurod2 KO mice. Cortical projection neurons (CPNs) over-migrated during embryogenesis, inducing abnormal thickness and laminar positioning of cortical layers. At juvenile ages, dendritic spine turnover and intrinsic excitability were increased in L5 CPNs. Differentially expressed genes in Neurod2 KO mice were enriched for voltage-gated ion channels, and the human orthologs of these genes were strongly associated with ASD. Furthermore, adult Neurod2 KO mice exhibited core ASD-like behavioral abnormalities. Finally, by generating Neurod2 conditional mutant mice we demonstrate that forebrain excitatory neuron-specific Neurod2 deletion recapitulates cellular and behavioral ASD phenotypes found in full KO mice. Our findings demonstrate crucial roles for Neurod2 in cortical development and function, whose alterations likely account for ASD and related symptoms in the newly defined NEUROD2 mutation syndrome.

neuroscience↗