Biology subjects

Galvao, A.

Publications and source records attributed to Galvao, A..

6 recordsLinked to original sources

bioRxiv2025

An Nlrp5-null mutation leads to attenuated de novo methylation in oocytes, accompanied by a significant reduction in DNMT3L

Nlrp5 encodes a core component of the subcortical maternal complex (SCMC) a cytoplasmic protein structure unique to the mammalian oocyte and cleavage-stage embryo. NLRP5 mutations have been identified in patients presenting with early embryo arrest, recurrent molar pregnancies and imprinting disorders. Correct patterning of DNA methylation over imprinted domains during oogenesis is necessary for faithful imprinting of genes. It was previously shown that oocytes with mutation in the human SCMC gene KHDC3L had globally impaired methylation, indicating that integrity of the SCMC is essential for correct establishment of DNA methylation at imprinted regions. Here, we present a multi-omic analysis of an Nlrp5- null mouse model, which in GV oocytes displays a misregulation of a broad range of maternal proteins, including proteins involved in several key developmental processes. This misregulation likely underlies impaired oocyte developmental competence. Amongst impacted proteins are several epigenetic modifiers, including a substantial reduction in DNMT3L; we show that de novo DNA methylation is attenuated in Nlrp5-null oocytes. This provides evidence for mechanisms leading to downstream misregulation of imprinted genes, which in turn, may result in imprinting syndromes, multi-locus imprinting disturbances (MLID) and hydatidiform moles.

developmental biology↗

bioRxiv2024

AutoGaitA - Automated Gait Analysis in Python

Individual behaviours require the nervous system to execute specialised motor programs, each characterised by unique patterns of coordinated movements across body parts. Deep learning approaches for body-posture tracking have facilitated the analysis of such motor programs. However, translating the resulting time-stamped coordinate datasets into meaningful kinematic representations of motor programs remains a long-standing challenge. We developed the versatile quantitative framework AutoGaitA (Automated Gait Analysis), a Python toolbox that enables comparisons of motor programs at multiple levels of granularity and across tracking methods, species and behaviours. AutoGaitA allowed us to demonstrate that flies, mice, and humans, despite divergent biomechanics, converge on the age-dependent loss of propulsive strength, and that, in mice, locomotor programs adapt as an integrated function of both age and task difficulty. AutoGaitA represents a truly universal framework for robust analyses of motor programs and changes thereof in health and disease, and across species and behaviours.

animal behavior and cognition↗

bioRxiv2023

A maternal-effect Padi6 variant results in abnormal nuclear localization of DNMT1 and failure of epigenetic reprogramming and zygotic genome activation in mouse embryos

PADI6 belongs to the multi-protein sub-cortical maternal complex (SCMC) that is present specifically in mammalian oocytes and early embryos. Maternal inactivation of SCMC genes generally results in early embryo lethality. In humans, variants in a subset of SCMC genes have been found in the healthy mothers of children affected by genomic imprinting disorders and characterized by multi-locus imprinting disturbances (MLID). However, how the SCMC controls the DNA methylation required to regulate imprinting remains poorly defined. To address this issue, we generated a mouse line carrying a Padi6 missense variant that had been identified in the mother of two sisters affected by Beckwith-Wiedemann syndrome and MLID. We found that if homozygous in female mice this variant resulted in interruption of embryo development at the 2-cell stage. Single-cell DNA methylation and RNA analyses demonstrated genomic hypermethylation, down-regulation of zygotic genome activation (ZGA) genes and up-regulation of maternal decay genes in 2-cell embryos from homozygous females. In addition, immunofluorescence analysis showed abnormal localization of DNMT1 and UHRF1 in mutant oocytes and zygotes. Taken together, this study demonstrates that PADI6 controls the subcellular localization of DNMT1 that is necessary for pre-implantation epigenetic reprogramming and ZGA.

genomics↗

bioRxiv2021

Leptin Signalling in the Ovary of Diet-Induced Obese Mice Regulates Activation of Nod-Like Receptor Protein 3 Inflammasome

1Obesity leads to ovarian dysfunction and the establishment of local leptin resistance. The aim of our study was to characterise levels of Nod-Like Receptor Protein 3 (NLRP3) inflammasome activation during obesity progression in the mouse ovaries and liver and test the putative role of leptin on its regulation. C57BL/6J mice were treated with equine chorionic gonadotropin (eCG) or human chorionic gonadotropin (hCG) for oestrous cycle synchronisation and ovaries collection. In diet-induced obesity (DIO) model, mice were fed chow diet (CD) or high fat diet (HFD) for 4 or 16 weeks (wk), whereas in hyperleptinemic model (LEPT), mice were injected with leptin for 16 days (16L) or saline (16C) and in the genetic obese leptin-deficient ob/ob (+/? and -/-) animals were fed CD for 4wk. Either ovaries and liver were collected, as well as cumulus cells (CCs) after superovulation from DIO and LEPT. In DIO protocol, protein expression of NLRP3 inflammasome components was increased in 4wk HFD, but decreased in 16wk HFD. Moreover LEPT and ob/ob models revealed NLRP3 and IL-1{beta} upregulation in 16L and downregulation in ob/ob. Transcriptome analysis of CC showed common genes between LEPT and 4wk HFD modulating NLRP3 inflammasome. Moreover analysis in the liver showed upregulation of NLRP3 protein only after 16wk HFD, but also the downregulation of NLRP3 protein in ob/ob-/-. We showed the link between leptin signalling and NLRP3 inflammasome activation in the ovary throughout obesity progression in mice, elucidating the molecular mechanisms underpinning ovarian failure in maternal obesity.

physiology↗

bioRxiv2020

Epigenetic change induced by in utero dietary challenge provokes phenotypic variability across multiple generations of mice

Transmission of epigenetic information between generations occurs in nematodes, flies and plants, mediated by specialised small RNA pathways, histone H3K9me3, H3K27me3, H4K16ac and DNA methylation1-3. In higher vertebrates, epidemiological and experimental evidence supports similar trans-generational effects4,5 although the mechanisms that underpin these are incompletely understood6-9. We generated a luciferase reporter knock-in mouse for the imprinted Dlk1 locus, to visualise and track epigenetic fidelity across generations. We showed that exposure to high-fat diet (HFD) in pregnancy provokes sustained re-expression of the normally silent maternal Dlk1 allele in offspring, coincident with increased DNA methylation at the Dlk1 sDMR. Interestingly, maternal Dlk1 mis-expression was also evident in the next generation (F2), exclusively in animals derived from F1-exposed females. Oocytes from these females showed altered microRNA and gene expression, without any major changes in underlying DNA methylation, and correctly imprinted Dlk1 expression resumed in subsequent generations (F3 onwards). Our results reveal how canonical and non-canonical imprinting mechanisms enable the foetal epigenome to adapt to in utero challenge to modulate the properties of two successive generations of offspring.

developmental biology↗

bioRxiv2019

Leptin resistance establishment in the ovary of diet-induced obese mice and its relationship with cumulus cells transcriptome

Background/AimsObesity is associated with infertility, decreased ovarian performance and lipotoxicity. However, little is known about the aetiology of these reproductive impairments. Here, we hypothesise that the majority of changes in ovarian physiology in diet-induced obesity (DIO) are a consequence of transcriptional changes downstream of altered leptin signalling. Therefore, we investigated the extent to which leptin signalling is altered in the ovary upon obesity with particular emphasis on effects on cumulus cells (CCs), the intimate functional companions of the oocyte. Furthermore, we used the pharmacological hyperleptinemic (LEPT) mouse model to compare transcriptional profiles to DIO. MethodsMice were subjected to DIO for 4 and 16 weeks (wk) and leptin treatment for 16 days, to study effects in the ovary in components of leptin signalling at the transcript and protein levels, using Western blot, Real-time PCR and immunostaining. Furthermore, we used low-cell RNA sequencing to characterise changes in the transcriptome of CCs in these models. ResultsIn the DIO model, obesity led to establishment of ovarian leptin resistance after 16 wk high fat diet (HFD), as evidenced by increases in the feedback regulator suppressor of cytokine signalling 3 (SOCS3) and decreases in the positive effectors phosphorylation of tyrosine 985 of leptin receptor (ObRb-pTyr985) and Janus kinase 2 (pJAK2). Transcriptome analysis of the CCs revealed a complex response to DIO, with large numbers and distinct sets of genes deregulated at early and late stages of obesity; in addition, there was a striking correlation between body weight and global transcriptome profile of CCs. Further analysis indicated that the transcriptome profile in 4 wk HFD CCs resembled that of LEPT CCs, in the upregulation of cellular trafficking and impairment in cytoskeleton organisation. Conversely, after 16 wk HFD CCs showed expression changes indicative of augmented inflammatory responses, cell morphogenesis, and decreased metabolism and transport, mainly as a consequence of the physiological changes of obesity. ConclusionObesity leads to ovarian leptin resistance and major time-dependent changes in gene expression in CCs, which in early obesity may be caused by increased leptin signalling in the ovary, whereas in late obesity are likely to be a consequence of metabolic changes taking place in the obese mother.

physiology↗