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Beyne, E.

Publications and source records attributed to Beyne, E..

3 recordsLinked to original sources

Daily intermittent fasting is an effective multiscale treatment in preclinical models of absence epilepsy

Absence epilepsy (AE) is characterized by brief but frequent seizures with loss of consciousness. Existing treatments have heavy side effects, are only partially effective and do not address the comorbidities, including cognitive and social deficits. A tripartite link between seizures, cognitive deficits and diet has been established. We focused on intermittent fasting (IF), a regime where daily periods of fasting alternate with periods of food intake, with no restrictions in the type or quantity of food consumed. To date, the effects of IF on infantile epilepsy have not been addressed. We evaluated the therapeutic potential of a daily, one-month protocol of IF on three established mouse models of AE: the Grm7AAA KI mouse, the Scn2a haploinsufficiency mouse and the pharmacologically-induced AY-9944 mouse model. We show a reduction of the seizure frequency in all models, as well as an improvement of the sociability deficits observed in two of the models, with no adverse effects. Focusing on the Grm7AAA KI model, we performed RNA sequencing in a one of the key brain areas of the absence seizure circuit, the thalamus. We detected a deregulation of genes involved in vascularization associated with the development of malformed blood vessels in epileptic mice. Along with its anti-seizure effects, IF was able to counteract both abnormal gene expression and vessel morphology. This study demonstrates for the first time the positive effects of IF on AE and could facilitate the implementation of the diet in clinical trials.

neuroscience↗

Spatio-temporal X-linked gene reactivation and site-specific retention of epigenetic silencing in the in vivo germline.

Random X-chromosome inactivation (XCI) is a hallmark of female mammalian somatic cells. This epigenetic mechanism, mediated by the long non-coding RNA Xist, occurs in the epiblast and is stably maintained to ensure proper dosage compensation of X-linked genes during life. However, this silencing is lost during primordial germ cell (PGC) development. Using a combination of single-cell allele-specific RNA sequencing and low-input chromatin profiling in developing in vivo PGC, we provide unprecedented detailed maps of gene reactivation. We demonstrated that PGC still carry a fully silent X chromosome on embryonic day (E) 9.5, despite the loss of Xist expression. X-linked genes are then gradually reactivated outside the Xist first-bound regions. At E12.5, a significant part of the inactive X chromosome (Xi) still resists reactivation, carrying an epigenetic memory of its silencing. Late-reactivated genes are enriched in repressive chromatin marks, including DNA methylation and H3K27me3 marks. Our results define the timing of reactivation of the silent X chromosome a key event in female PGC reprogramming with direct implications for reproduction.

developmental biology↗

Chromatin-associated MRN complex protects highly transcribing genes from genomic instability

The MRN-MDC1 complex plays a central role in the DNA damage response (DDR) and repair. Using Proteomics of Isolated Chromatin Fragments (PICh), we identified DDR factors, such as MDC1, among those that become highly associated with a genomic locus upon transcriptional activation. Purification of endogenous MDC1, in the absence of exogenous DNA damage, revealed its interaction with factors involved in gene expression and co-transcriptional RNA processing, in addition to DDR factors. ChIP-seq analysis showed that MDC1 interacting factors, MRE11 and NBS1 subunits of MRN, were co-localized throughout the genome and notably at TSSs and gene bodies of actively transcribing genes. Blockade of transcriptional elongation showed that binding of MRN was dependent on the RNAPII transcriptional complex rather than transcription per se. Depletion of MRN increased RNAPII abundance at TSSs and gene bodies of MRE11/NBS1-bound genes. Prolonged exposure of cells to either MRE11- or NBS1-depletion led to single nucleotide polymorphism formation across actively transcribing, MRE11 or NBS1 target genes. These data support a model by which association of the MRN complex with the transcriptional machinery constitutively scans active genes for transcription-induced DNA damage to preserve the integrity of the coding genome.

molecular biology↗