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Development (Cambridge, England) Jun 2024Bone morphogenic protein (BMP) signaling plays an essential and highly conserved role in embryo axial patterning in animal species. However, in mammalian embryos, which...
Bone morphogenic protein (BMP) signaling plays an essential and highly conserved role in embryo axial patterning in animal species. However, in mammalian embryos, which develop inside the mother, early development includes a preimplantation stage, which does not occur in externally developing embryos. During preimplantation, the epiblast is segregated from extra-embryonic lineages that enable implantation and development in utero. Yet, the requirement for BMP signaling is imprecisely defined in mouse early embryos. Here, we show that, in contrast to previous reports, BMP signaling (SMAD1/5/9 phosphorylation) is not detectable until implantation when it is detected in the primitive endoderm - an extra-embryonic lineage. Moreover, preimplantation development appears to be normal following deletion of maternal and zygotic Smad4, an essential effector of canonical BMP signaling. In fact, mice lacking maternal Smad4 are viable. Finally, we uncover a new requirement for zygotic Smad4 in epiblast scaling and cavitation immediately after implantation, via a mechanism involving FGFR/ERK attenuation. Altogether, our results demonstrate no role for BMP4/SMAD4 in the first lineage decisions during mouse development. Rather, multi-pathway signaling among embryonic and extra-embryonic cell types drives epiblast morphogenesis postimplantation.
Topics: Animals; Smad4 Protein; Germ Layers; Embryo Implantation; Mice; Morphogenesis; Female; Signal Transduction; Bone Morphogenetic Protein 4; Gene Expression Regulation, Developmental; Embryonic Development; Mice, Knockout; Embryo, Mammalian; Endoderm; Blastocyst
PubMed: 38752427
DOI: 10.1242/dev.202377 -
BioRxiv : the Preprint Server For... Apr 2024Complexes that control mRNA stability and translation promote timely cell-state transitions during differentiation by ensuring appropriate expression patterns of key...
Complexes that control mRNA stability and translation promote timely cell-state transitions during differentiation by ensuring appropriate expression patterns of key developmental regulators. The RNA-binding protein Brain tumor (Brat) promotes degradation of target transcripts during the maternal-to-zygotic transition in syncytial embryos and in uncommitted intermediate neural progenitors (immature INPs). We identified Ubiquitin-specific protease 5 (Usp5) as a Brat interactor essential for the degradation of Brat target mRNAs in both cell types. Usp5 promotes Brat-dedadenylase pre-complex assembly in mitotic neural stem cells (neuroblasts) by bridging Brat and the scaffolding components of deadenylase complexes lacking their catalytic subunits. The adaptor protein Miranda binds the RNA-binding domain of Brat, limiting its ability to bind target mRNAs in mitotic neuroblasts. Cortical displacement of Miranda activates Brat-mediated mRNA decay in immature INPs. We propose that the assembly of an enzymatically inactive and RNA-binding-deficient pre-complex poises mRNA degradation machineries for rapid activation driving timely developmental transitions.
PubMed: 38746105
DOI: 10.1101/2024.04.29.591706 -
Cell Death Discovery May 2024Phosphorylated H2AX, known as γH2AX, forms in response to genotoxic insults in somatic cells. Despite the high abundance of H2AX in zygotes, the level of...
Phosphorylated H2AX, known as γH2AX, forms in response to genotoxic insults in somatic cells. Despite the high abundance of H2AX in zygotes, the level of irradiation-induced γH2AX is low at this stage. Another H2A variant, TH2A, is present at a high level in zygotes and can also be phosphorylated at its carboxyl end. We constructed H2AX- or TH2A-deleted mice using CRISPR Cas9 and investigated the role of these H2A variants in the DNA damage response (DDR) of zygotes exposed to γ-ray irradiation at the G2 phase. Our results showed that compared to irradiated wild-type zygotes, irradiation significantly reduced the developmental rates to the blastocyst stage in H2AX-deleted zygotes but not in TH2A-deleted ones. Furthermore, live cell imaging revealed that the G2 checkpoint was activated in H2AX-deleted zygotes, but the duration of arrest was significantly shorter than in wild-type and TH2A-deleted zygotes. The number of micronuclei was significantly higher in H2AX-deleted embryos after the first cleavage, possibly due to the shortened cell cycle arrest of damaged embryos and, consequently, the insufficient time for DNA repair. Notably, FRAP analysis suggested the involvement of H2AX in chromatin relaxation. Moreover, phosphorylated CHK2 foci were found in irradiated wild-type zygotes but not in H2AX-deleted ones, suggesting a critical role of these foci in maintaining cell cycle arrest for DNA repair. In conclusion, H2AX, but not TH2A, is involved in the DDR of zygotes, likely by creating a relaxed chromatin structure with enhanced accessibility for DNA repair proteins and by facilitating the formation of pCHK2 foci to prevent premature cleavage.
PubMed: 38744857
DOI: 10.1038/s41420-024-01999-0 -
The Journal of Reproduction and... May 2024Intracytoplasmic sperm injection (ICSI) is clinically used to treat obstructive/nonobstructive azoospermia. This study compared the efficacy of ICSI with cauda...
Intracytoplasmic sperm injection (ICSI) is clinically used to treat obstructive/nonobstructive azoospermia. This study compared the efficacy of ICSI with cauda epididymal and testicular sperm in Wistar (WI) and Brown-Norway (BN) rats. The transfer of ICSI oocytes with cryopreserved epididymal and testicular WI sperm resulted in offspring production of 26.2% and 3.7%-4.7%, respectively (P < 0.05). Treatments for artificial oocyte activation (AOA) and acrosome removal improved pronuclear formation in BN-ICSI oocytes; however, only AOA treatment was effective in producing offspring (3.7%-6.5%). In the case of ICSI with testicular sperm (TESE-ICSI), one offspring (0.6%) was derived from the BN-TESE-ICSI oocytes. The application of AOA or a hypo-osmotic sperm suspension did not improve the production of TESE-ICSI offspring. Thus, outbred WI rat offspring can be produced by using ICSI and less efficiently by using TESE-ICSI. Challenges in producing offspring by using ICSI/TESE-ICSI in inbred BN strains require further investigation.
PubMed: 38735740
DOI: 10.1262/jrd.2024-030 -
Stem Cell Reports Jun 2024Removal of somatic histone H3 lysine 9 trimethylation (H3K9me3) from the embryonic genome can improve the efficiency of mammalian cloning using somatic cell nuclear...
Removal of somatic histone H3 lysine 9 trimethylation (H3K9me3) from the embryonic genome can improve the efficiency of mammalian cloning using somatic cell nuclear transfer (SCNT). However, this strategy involves the injection of histone demethylase mRNA into embryos, which is limiting because of its invasive and labor-consuming nature. Here, we report that treatment with an inhibitor of G9a (G9ai), the major histone methyltransferase that introduces H3K9me1/2 in mammals, greatly improved the development of mouse SCNT embryos. Intriguingly, G9ai caused an immediate reduction of H3K9me1/2, a secondary loss of H3K9me3 in SCNT embryos, and increased the birth rate of cloned pups about 5-fold (up to 3.9%). G9ai combined with the histone deacetylase inhibitor trichostatin A further improved this rate to 14.5%. Mechanistically, G9ai and TSA synergistically enhanced H3K9me3 demethylation and boosted zygotic genome activation. Thus, we established an easy, highly effective SCNT protocol that would enhance future cloning research and applications.
Topics: Animals; Histones; Nuclear Transfer Techniques; Mice; Histone-Lysine N-Methyltransferase; Methylation; Cloning, Organism; Embryo, Mammalian; Embryonic Development; Hydroxamic Acids; Female; Histone Deacetylase Inhibitors
PubMed: 38729154
DOI: 10.1016/j.stemcr.2024.04.003 -
Marine Environmental Research Jun 2024Marine macroalgal forests are facing unprecedented challenges worldwide due to the accelerating impacts of climate change. These ecosystems play a crucial role in...
Marine macroalgal forests are facing unprecedented challenges worldwide due to the accelerating impacts of climate change. These ecosystems play a crucial role in supporting biodiversity, coastal ecosystem functions and services, and are indeed object of several conservation and restoration measures. The Mediterranean Sea is warming faster than the oceans and thermal anomalies are occurring with increasing intensity, frequency and duration. Along the Mediterranean coasts, Cystoseira sensu lato species are the main representatives of macroalgal forests and their decline has been widely documented. Some relevant achievements in the implementation of ecological restoration have been obtained, but rising temperatures and the occurrence of thermal anomalies increasingly threaten the success of these restoration attempts. In the summer of 2022, ex-situ restoration actions of Ericaria amentacea were carried out by collecting fertile material from three donor sites of the Italian coasts along a latitudinal gradient, during the period of sexual maturity (June/July). Noteworthy during the summer of 2022, anomalous thermal conditions were recorded at the donor sites, with sea surface temperatures exceeding the climatological mean up to 4.3 °C and heatwaves lasting up to 78 days. Our results suggest that these thermal anomalies may have affected the culture of the embryos in both the pre- and post-zygotic phases, resulting in significantly low culture efficiency at the three donor sites. The reproductive structures showed some abnormalities, fertilization of eggs was lower and embryo growth was slower, resulting in lower percent cover of seedlings on the tiles and lower survival rate. The observations underscore the vulnerability of Mediterranean algal forests to global change and highlight additional challenges for their restoration due to the increasing frequency and severity of thermal anomalies, emphasizing the need for adaptive strategies and a comprehensive understanding of the species in a changing climate. Marine forest restoration requires long lasting projects, to allow for long-term monitoring and better understanding the biology of the species and for mitigating stochastic events that can cause the temporary failure of efforts.
Topics: Climate Change; Mediterranean Sea; Temperature; Ecosystem; Forests; Conservation of Natural Resources; Seaweed; Ericaceae; Environmental Restoration and Remediation; Italy
PubMed: 38728798
DOI: 10.1016/j.marenvres.2024.106537 -
Frontiers in Allergy 2024Progesterone is an endogenous hormone, produced by the adrenal cortex, the gonads and in women, its source is the corpus luteum. Progesterone is produced in the late... (Review)
Review
Progesterone is an endogenous hormone, produced by the adrenal cortex, the gonads and in women, its source is the corpus luteum. Progesterone is produced in the late phase of the menstrual cycle, when implantation of the zygote does not occur, the corpus luteum involutes and the release of progesterone is suppressed, thus initiating menstruation. Progestogen Hypersensitivity were initially identified as hormone allergy and were related to endogenous reactions to hormones and alteration of ovarian function. Skin manifestations such as dermatitis or urticaria were initially reported and described as progesterone autoimmune dermatitis, although the immune-mediated mechanism was not clear. Currently there is no standardization for or tests for Progestogen Hypersensitivity diagnosis. In this review, we will address the different diagnostic methods of this disease.
PubMed: 38720769
DOI: 10.3389/falgy.2024.1384140 -
Nature Neuroscience Jun 2024Cortical malformations such as focal cortical dysplasia type II (FCDII) are associated with pediatric drug-resistant epilepsy that necessitates neurosurgery. FCDII...
Cortical malformations such as focal cortical dysplasia type II (FCDII) are associated with pediatric drug-resistant epilepsy that necessitates neurosurgery. FCDII results from somatic mosaicism due to post-zygotic mutations in genes of the PI3K-AKT-mTOR pathway, which produce a subset of dysmorphic cells clustered within healthy brain tissue. Here we show a correlation between epileptiform activity in acute cortical slices obtained from human surgical FCDII brain tissues and the density of dysmorphic neurons. We uncovered multiple signatures of cellular senescence in these pathological cells, including p53/p16 expression, SASP expression and senescence-associated β-galactosidase activity. We also show that administration of senolytic drugs (dasatinib/quercetin) decreases the load of senescent cells and reduces seizure frequency in an Mtor FCDII preclinical mouse model, providing proof of concept that senotherapy may be a useful approach to control seizures. These findings pave the way for therapeutic strategies selectively targeting mutated senescent cells in FCDII brain tissue.
Topics: Animals; TOR Serine-Threonine Kinases; Mice; Humans; Seizures; Senotherapeutics; Cellular Senescence; Dasatinib; Epilepsy; Male; Malformations of Cortical Development; Neurons; Female
PubMed: 38710875
DOI: 10.1038/s41593-024-01634-2 -
Open Biology May 2024The nucleolus is the most prominent liquid droplet-like membrane-less organelle in mammalian cells. Unlike the nucleolus in terminally differentiated somatic cells,...
The nucleolus is the most prominent liquid droplet-like membrane-less organelle in mammalian cells. Unlike the nucleolus in terminally differentiated somatic cells, those in totipotent cells, such as murine zygotes or two-cell embryos, have a unique nucleolar structure known as nucleolus precursor bodies (NPBs). Previously, it was widely accepted that NPBs in zygotes are simply passive repositories of materials that will be gradually used to construct a fully functional nucleolus after zygotic genome activation (ZGA). However, recent research studies have challenged this simplistic view and demonstrated that functions of the NPBs go beyond ribosome biogenesis. In this review, we provide a snapshot of the functions of NPBs in zygotes and early two-cell embryos in mice. We propose that these membrane-less organelles function as a regulatory hub for chromatin organization. On the one hand, NPBs provide the structural platform for centric and pericentric chromatin remodelling. On the other hand, the dynamic changes in nucleolar structure control the release of the pioneer factors (i.e. double homeobox (Dux)). It appears that during transition from totipotency to pluripotency, decline of totipotency and initiation of fully functional nucleolus formation are not independent events but are interconnected. Consequently, it is reasonable to hypothesize that dissecting more unknown functions of NPBs may shed more light on the enigmas of early embryonic development and may ultimately provide novel approaches to improve reprogramming efficiency.
Topics: Animals; Humans; Mice; Cell Nucleolus; Chromatin; Chromatin Assembly and Disassembly; Embryonic Development; Gene Expression Regulation, Developmental; Zygote
PubMed: 38689555
DOI: 10.1098/rsob.230358 -
Molecular Biology and Evolution May 2024Maternal genes have a pivotal role in regulating metazoan early development. As such their functions have been extensively studied since the dawn of developmental... (Comparative Study)
Comparative Study
Maternal genes have a pivotal role in regulating metazoan early development. As such their functions have been extensively studied since the dawn of developmental biology. The temporal and spatial dynamics of their transcripts have been thoroughly described in model organisms and their functions have been undergoing heavy investigations. Yet, less is known about the evolutionary changes shaping their presence within diverse oocytes. Due to their unique maternal inheritance pattern, a high degree is predicted to be present when it comes to their expression. Insofar only limited and conflicting results have emerged around it. Here, we set out to elucidate which evolutionary changes could be detected in the maternal gene expression patterns using phylogenetic comparative methods on RNAseq data from 43 species. Using normalized gene expression values and fold change information throughout early development we set out to find the best-fitting evolutionary model. Through modeling, we find evidence supporting both the high degree of divergence and constraint on gene expression values, together with their temporal dynamics. Furthermore, we find that maternal gene expression alone can be used to explain the reproductive modes of different species. Together, these results suggest a highly dynamic evolutionary landscape of maternal gene expression. We also propose a possible functional dichotomy of maternal genes which is influenced by the reproductive strategy undertaken by examined species.
Topics: Animals; Reproduction; Biological Evolution; Female; Phylogeny; Maternal Inheritance; Evolution, Molecular
PubMed: 38679468
DOI: 10.1093/molbev/msae081