Biology subjects

Barres, R.

Publications and source records attributed to Barres, R..

11 recordsLinked to original sources

bioRxiv2026

Imaging-based spatial isoform transcriptomics resolves transcript diversity at cellular and subcellular resolution

Spatial transcriptomics has transformed our understanding of tissue organization, yet current high-throughput approaches remain largely confined to a gene-centric paradigm, precluding systematic characterization of spatially resolved transcript isoform diversity. Here, we introduce imaging-based spatial isoform transcriptomics (iSiT), a framework enabling simultaneous large-scale gene expression and targeted transcript isoform profiling on the commercial Xenium platform. iSiT resolves alternative splicing events that alter internal transcript structure at cellular and subcellular resolution using a single junction-specific probe per target. To facilitate broader adoption, we developed ProbeHarbour, an open-source toolkit for the design, characterization and management of isoform-specific probes. We demonstrate iSiT in the postnatal mouse brain by combining the Prime 5K gene-level panel with isoform-specific detection of 45 synaptogenesis-associated genes. By extending spatial transcriptomics beyond gene-level measurements, iSiT provides a scalable and readily accessible framework for investigating spatial isoform regulation in development and disease.

neuroscience↗

bioRxiv2025

Exercise induces time-dependent but not sex-specific transcriptomic changes in healthy human skeletal muscle

Elucidating the time-dependent transcriptional response of skeletal muscle to exercise is essential for uncovering the molecular mechanisms that drive its health-promoting effects. However, previous studies have been limited by a small number of muscle biopsies, often collected at arbitrary time points post-exercise, and in predominantly male subjects. Using the most comprehensive skeletal muscle biopsy time course following a single session of exercise in both males and females, we identified over 16,600 differentially expressed genes (DEGs), including more than 7,000 novel exercise-responsive genes. Of these DEGs, the magnitude of differential expression in 60% of genes was influenced by cardiorespiratory fitness. Although most mitochondrial genes were differentially expressed after exercise, the majority were downregulated at 24-48 hours, suggesting that mitochondrial protein expression may be regulated by post-transcriptional regulation. Despite 1,193 genes showing sex-specific expression at baseline, exercise-induced gene expression differences were minimal between males and females, suggesting that when cardiorespiratory fitness and exercise stimulus are matched, skeletal muscle adaptations are similar between sexes. To enhance data accessibility, we created an interactive Shiny app (https://BishopLab.shinyapps.io/EXERgene/) that allows users to investigate specific genes and interrogate potential mechanisms of skeletal muscle adaptation to exercise.

physiology↗

bioRxiv2025

Dietary macronutrients modulate the proteome of brown adipose tissue in males and their female offspring

Brown adipose tissue (BAT) dissipates energy as heat, not only under cold exposure but also in the dissipation of excess ingested energy. Therefore, enhancing BAT activity is a potential avenue to combat weight gain. Dietary macronutrient composition influences BAT size and has recently been shown to influence BAT size of daughters through the patriline of C57BL/6J mice. However, the effects of macronutrient composition and any paternal effects on BAT function have yet to be characterised. Using the Geometric Framework for Nutrition, we investigated the effects of macronutrient composition on the BAT proteome in male mice and intergenerational effects in their offspring. In fathers, >50% of the proteome was affected by macronutrient composition, with distinct clusters of proteins that responded in similar ways. We identified two clusters with inverse patterns that correlated with BAT mass. Notably, UCP1 was reduced on low fat diets that promoted increased BAT mass, while there were increased levels of proteins involved in protein turnover on those same diets. The same diets also led to a reduction in proteins involved in purine biosynthesis (often UCP1 inhibitors). We did not find any effects of paternal diet on the BAT proteome in sons, but paternal protein intake negatively affected basigin expression in daughters - a protein that regulates UCP1 transcription. Our results highlight that dietary macronutrient composition in males remodels the protein expression landscape of BAT, and pre-conceptionally reprograms BAT expression profiles of female offspring.

molecular biology↗

bioRxiv2025

Muscle Cathepsin B treatment improves behavioral and neurogenic deficits in a mouse model of Alzheimer's Disease

Muscle secretes factors during exercise that enhance cognition. Myokine Cathepsin B (Ctsb) is linked to memory function, but its role in neurodegenerative disease is unclear. Here we show that AAV-vector-mediated Ctsb overexpression in skeletal muscle in an Alzheimers Disease (AD) mouse model (APP/PS1), improves motor coordination, memory function and adult hippocampal neurogenesis, while plaque pathology and neuroinflammation remain unchanged. Additionally, in AD mice, Ctsb treatment modifies hippocampal, muscle and plasma proteomic profiles to resemble that of wildtype controls. Conversely, in wildtype mice, Ctsb expression causes memory deficits and results in protein profiles across tissues that are comparable to AD control mice. In AD mice, Ctsb treatment increases the abundance of hippocampal proteins involved in mRNA metabolism and protein synthesis, including those relevant to adult hippocampal neurogenesis and memory function. Furthermore, Ctsb treatment enhances plasma metabolic and mitochondrial processes, and reduces inflammatory responses. In muscle, Ctsb expression elevates protein translation in AD mice, whereas in wildtype mice mitochondrial proteins decrease. Overall, the biological changes in the treatment groups are consistent with effects on memory function. Thus, skeletal muscle Ctsb application has potential as an AD therapeutic intervention.

neuroscience↗

bioRxiv2024

A multi-omics census reveals obesity-associated microRNA miR-let-7 as novel instigator of adipose mitochondrial dysfunction and of intergenerational metabolic decline.

We here describe that obesity and weight loss in male mice cause reversible abnormalities in glucose and lipid metabolism, serum metabolomes and lipidomes as well as expression of microRNAs, mRNAs and proteins controlling mitochondrial function in epididymal white adipose tissue. When mating obese male mice with lean females, we observed reductions in expression and translation of genes encoding mitochondrial respiratory components in (F1) offspring that closely resemble those observed in the paternal (F0) generation. When mapping miRNA regulation across somatic organs (i.e., liver, adipose) and sperm and F0/1 generations, we found that obesity and weight loss reversibly affected miRNA levels, and that let-7 isoforms were induced in obese F0 and F1 adipose tissue and sperm of obese F0 mice, eliciting qualitatively similar responses in two adjacent tissues. Overexpressing let-7 in adipocytes silenced DICER1, a miRNA processing enzyme crucial for adipose adaptation to obesity as evidenced by deficiencies in mitochondrial function following DICER1 loss in primary adipocytes. Also, microinjection of synthetic let-7 mimetics at physiological levels found in obese sperm into zygotes from lean mice elicited glucose intolerance and impediments in adipose mitochondrial gene expression in mice sired from let-7 microinjected zygotes, phenocopying hereditary aspects of paternal obesity. When performing single-cell RNA-Seq of miRNA-injected embryos, let-7 impaired mitochondrial gene expression, suggesting altered oxidative metabolism following zygotic let-7 delivery. When studying miRNA alterations in human semen, lifestyle-induced weight loss downregulated hsa-let-7, suggesting similar roles for human let-7 in gametic epigenomes and embryogenesis.

physiology↗

bioRxiv2024

High fat low carbohydrate diet is linked to protection against CNS autoimmunity

Multiple sclerosis (MS) is a common central nervous system (CNS) autoimmune disease, and diets and nutrients are emerging as critical contributing factors. However, a comprehensive understanding of their impacts and the underlying mechanisms involved is lacking. Harnessing state-of-the-art nutritional geometry analytical methods, we first revealed that globally, increased carbohydrate supply was associated with increased MS disease burden, while fat supply had an opposite effect. Furthermore, in a preclinical MS mouse model, experimental autoimmune encephalomyelitis (EAE), we found that an isocaloric diet high in carbohydrate aggravated EAE, while a diet enriched in fat was fully protective. This was reflected by reduced neuroinflammation and skewing towards anti-inflammatory phenotypes, which involved transcriptomic, epigenetic and immunometabolic changes. We showcased that manipulating diets is a potentially efficient and cost-effective approach to prevent and/or ameliorate EAE. This exhibits translational potentials for intervention/prevention of MS and possibly other autoimmune diseases.

immunology↗

bioRxiv2023

Exposure to childhood maltreatment is associated with changes in sperm small non-coding RNA and DNA methylation profiles

BackgroundChildhood maltreatment exposure (CME) increases the risk of adverse long-term health consequences for the exposed individual. Animal studies suggest that CME may also influence the health and behaviour in the next generation offspring through CME-driven epigenetic changes in the paternal germ line. The contribution of paternal early life stress on the health of the next generation in humans is not fully elucidated. MethodsIn this study, we measured paternal CME using the Trauma and Distress Scale (TADS) questionnaire and mapped sperm-borne sncRNAs expression by small RNA sequencing (small RNA-seq) and DNA methylation (DNAme) in spermatozoa by reduced-representation bisulfite sequencing (RRBS-seq) in males from the FinnBrain Birth Cohort Study. The study design was a (nested) case-control study, high-TADS (TADS [≥] 39, n = 25 for DNAme and n = 14 for small RNA-seq) and low-TADS (TADS [≤] 10, n = 30 for DNAme and n = 16 for small RNA-seq)). Groups were compared to identify specific epigenetic signatures associated with TADS levels in the spermatozoa of participants. ResultsCompared to the control group, high CME was associated with altered sperm sncRNA expression and DNAme profiles. Particularly, we identified several tRNA-derived small RNAs (tsRNAs) and miRNAs with markedly changed levels in males with high CME. DNA methylation analysis identified several genomic regions with differentially methylated CpGs between groups. Notably, we identified two epigenetic marks related to brain development with distinct profiles between CME and controls, the miRNA hsa-mir-34c-5p and differential methylation of the region in proximity of FSCN1. ConclusionsThis study provides further evidence that early life stress influences the paternal germ line epigenome and supports a possible contribution in the development of the central nervous system of the next generation.

molecular biology↗

bioRxiv2021

Single-cell bisulfite sequencing of spermatozoa from lean and obese humans reveals potential for the transmission of epimutations

Epigenetic marks in gametes modulate developmental programming after fertilization. Spermatozoa from obese men exhibit distinct epigenetic signatures compared to lean men, however, whether epigenetic differences are concentrated in a sub-population of spermatozoa or spread across the ejaculate population is unknown. Here, by using whole-genome single-cell bisulfite sequencing on 87 motile spermatozoa from 8 individuals (4 lean and 4 obese), we found that spermatozoa within single ejaculates are highly heterogeneous and contain subsets of spermatozoa with marked imprinting defects. Comparing lean and obese subjects, we discovered methylation differences across two large CpG dense regions located near PPM1D and LINC01237. These findings confirm that sperm DNA methylation is altered in human obesity and indicate that single ejaculates contain subpopulations of spermatozoa carrying distinct DNA methylation patterns. Distinct epigenetic patterns of spermatozoa within an ejaculate may result in different intergenerational effects and therefore influence strategies aiming to prevent epigenetic-related disorders in the offspring.

genomics↗

bioRxiv2021

Disrupted circadian core-clock oscillations in Type 2 Diabetes are linked to altered rhythmic mitochondrial metabolism

Circadian rhythms are generated by an auto-regulatory feedback loop composed of transcriptional activators and repressors. Disruption of circadian rhythms contributes to Type 2 diabetes (T2D) pathogenesis. We elucidated whether altered circadian rhythmicity of clock genes is associated with metabolic dysfunction in T2D. Transcriptional cycling of core clock genes ARNTL, CLOCK, CRY1 and NR1D1 was altered in skeletal muscle from individuals with T2D and this was coupled with reduced number and amplitude of cycling genes and disturbed circadian oxygen consumption. Mitochondrial associated genes were enriched for differential circadian amplitudes in T2D, and positively correlated with insulin sensitivity. ChIP- sequencing identified CLOCK and BMAL1 binding to circadian mitochondrial genes associated with insulin sensitivity, implicating regulation by the core clock. Mitochondria disruption altered core-clock gene expression and free-radical production, phenomena that were restored by resveratrol treatment. We identify bi-directional communication between mitochondrial function and rhythmic gene expression, processes which are disturbed in diabetes.

physiology↗

bioRxiv2021

Circadian Transcriptomic and Epigenomic Remodeling in Response to Lipid Overload and Human Obesity

Obesity and elevated circulating lipids may impair metabolism by disrupting the molecular circadian clock. We tested the hypothesis that lipid-overload may interact with the circadian clock and alter the rhythmicity of gene expression through epigenomic mechanisms in skeletal muscle. Palmitate reprogrammed the circadian transcriptome in myotubes without altering the rhythmic mRNA expression of core clock genes. Genes with enhanced cycling in response to palmitate were associated with post-translational modification of histones. Cycling of histone 3 lysine 27 acetylation (H3K27ac), a marker of active gene enhancers, was modified by palmitate treatment. Chromatin immunoprecipitation and sequencing confirmed that palmitate exposure altered the cycling of DNA regions associated with H3K27ac. Overlap of mRNA and DNA regions associated with H3K27ac and pharmacological inhibition of histone acetyl transferases revealed novel cycling genes associated with lipid exposure of primary human myotubes. Palmitate exposure disrupts transcriptomic rhythmicity and modifies enhancers through changes in histone H3K27 acetylation in a circadian manner. Thus, histone acetylation is responsive to lipid-overload and redirects the circadian chromatin landscape leading to reprogramming of circadian genes in skeletal muscle.

physiology↗

bioRxiv2020

GREM1 is epigenetically reprogrammed in muscle cells after exercise training and controls myogenesis and metabolism

Exercise training improves skeletal muscle function, notably through tissue regeneration by muscle stem cells. Here, we hypothesized that exercise training reprograms the epigenome of muscle cell, which could account for better muscle function. Genome-wide DNA methylation of myotube cultures established from middle-aged obese men before and after endurance exercise training identified a differentially methylated region (DMR) located downstream of Gremlin 1 (GREM1), which was associated with increased GREM1 expression. GREM1 expression was lower in muscle satellite cells from obese, compared to lean mice, and exercise training restored GREM1 levels to those of control animals. We show that GREM1 regulates muscle differentiation through the negative control of satellite cell self-renewal, and that GREM1 controls muscle lineage commitment and lipid oxidation through the AMPK pathway. Our study identifies novel functions of GREM1 and reveals an epigenetic mechanism by which exercise training reprograms muscle stem cells to improve skeletal muscle function.

cell biology↗