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At least 19 recordsLinked to original sources

PubMed2026

Thyroid hormone deprivation creates an immunological signature in the mouse liver, involving Kupffer cell presentation as the mouse ages.

PURPOSE: Aging is associated with an increased prevalence of chronic liver diseases suggesting impaired immune and metabolic function. In addition, thyroid hormone (TH) impacts liver physiology and TH deprivation or excess negatively affect organ maintenance. However, whether age-dependent consequences of TH alterations are reflected in a liver-specific adaptation is unknown so far. The present study aimed to characterize the impact of TH deprivation or excess on the liver transcriptome during aging. METHODS: Five- and 21-month-old male C57BL/6 mice were exposed either to chronic TH deprivation or to chronic TH excess and compared to control treatment by microarray-based liver transcriptome analysis. RESULTS: Significant roles of both TH state and age became obvious: Bioinformatic analysis of the liver transcriptome data revealed an age-dependent immune signature by chronic TH deprivation, an age-dependent immune and metabolic signature independent of exogenous TH modulation, as well as an age-dependent metabolic signature by chronic TH excess. Published data of single cell transcriptomic atlas characterizing aging tissues in the mouse were compared with our data and revealed Kupffer cell presentation in the immunological signature by TH deprivation during aging. Literature data for four prominent differentially expressed genes, namely C1qb, C3ar1, Ctss, and Msr1, revealed that the complement system, extracellular matrix remodelling, as well as the proinflammatory phenotype of Kupffer cells are altered by TH deprivation during aging. CONCLUSION: In conclusion, our study illuminates the interplay between TH deprivation, aging, and liver transcriptome signatures, highlighting potential implications for immune function and tissue maintenance, particularly through the modulation of Kupffer cell presentation.

Animals↗

PubMed2026

Spatial proteomic mapping of the human and mouse retina using IBEX.

We generated a comparative spatial proteomic atlas of the human and mouse retina using a highly multiplexed immunohistochemistry technique called iterative bleaching extends multiplexity (IBEX). We refined the IBEX workflow by integrating an antibody dissociation option alongside chemical bleaching. This dual strategy enabled removal of the entire antibody complex, permitting the flexible use of antibodies from the same host species across iterative cycles. We coupled this workflow with super-resolution imaging via deconvolution and applied it to the retina of healthy humans and WT mice and the Crb1rd8 mouse model. We successfully imaged over 25 protein markers on human and mouse tissue sections, generating spatial atlases of the major retinal cell populations. Cross-species protein expression was compared to scRNA-seq datasets to identify protein and transcript disparities. Super-resolution IBEX delineated the ultrastructural features of the outer limiting membrane (OLM), identifying CD44 as a core structural component tightly colocalized with a highly organized F-actin belt within Müller glial endfeet. Using the Crb1rd8 mouse model, disruption of this complex was spatially associated with rosette formation and OLM structural failure. In summary, spatial proteomic atlases of the human and mouse retina were used to reveal insights into the arrangement of major retinal cell populations and OLM structure.

Animals↗

PubMed2024

Design and evaluation of antisense sequence length for modified mouse U7 small nuclear RNA to induce efficient pre-messenger RNA splicing modulation in vitro.

Pre-messenger RNA (pre-mRNA) splicing modulation is an attractive approach for investigating the mechanisms of genetic disorders caused by mis-splicing. Previous reports have indicated that a modified U7 small nuclear RNA (U7 snRNA) is a prospective tool for modulating splicing both in vitro and in vivo. To date, very few studies have investigated the role of antisense sequence length in modified U7 snRNA. In this study, we designed a series of antisense sequences with various lengths and evaluated their efficiency in inducing splicing modulation. To express modified U7 snRNAs, we constructed a series of plasmid DNA sequences which codes cytomegalovirus (CMV) enhancer, human U1 promoter, and modified mouse U7 snRNAs with antisense sequences of different lengths. We evaluated in vitro splicing modulation efficiency using a luciferase reporter system for simple and precise evaluation as well as reverse transcription-polymerase chain reaction to monitor splicing patterns. Our in vitro assay findings suggest that antisense sequences of modified mouse U7 snRNAs have an optimal length for efficient splicing modulation, which depends on the target exon. In addition, antisense sequences that were either too long or too short decreased splicing modulation efficiency. To confirm reproducibility, we performed an in vitro assay using two target genes, mouse Fas and mouse Dmd. Together, our data suggests that the antisense sequence length should be optimized for modified mouse U7 snRNAs to induce efficient splicing modulation.

RNA, Small Nuclear↗

PubMed2025

How to Study Gene Expression and Gain of Function of Hoxb1 in Mouse Heart Development.

Anterior Hox genes are required for genetic identity and anterior posterior patterning of the second heart field (SHF), which contributes to the formation of the embryonic heart in vertebrates. Defective contribution of SHF cells to the arterial or venous pole of the heart is often associated with severe congenital heart defects. The mouse Cre-lox system allows the activation of expression of any gene of interest in restricted tissues. We developed a gain of function approach that relies on the use of a CAG transgene to ectopically activate Hoxb1 expression in SHF cardiac progenitor cells through specific Cre activation. Therefore, we generated a floxed transgenic mouse line, CAG-Hoxb1-eGFP, which upon recombination by Cre recombinase conditionally induces robust Hoxb1 and eGFP expression. When induced within the anterior SHF lineage, we detected heart defects in mouse embryos such as right ventricular hypoplasia. Here, we describe the strategy for generating and genetically crossing this transgenic mouse line. We also provide detailed protocols for whole-mount embryo and paraffin section in situ RNAscope hybridization and X-gal staining allowing investigation of SHF contribution during heart development.

Animals↗

PubMed2025

Genome-Wide Silencer Screening Reveals Key Silencer Modulating Reprogramming Efficiency in Mouse Induced Pluripotent Stem Cells.

The majority of the mouse genome is composed of non-coding regions, which harbor numerous regulatory sequences essential for gene regulation. While extensive research focuses on enhancers that activate gene expression, the role of silencers that repress gene expression remains less explored. In this study, the first genome-wide identification of silencers in the mouse genome is conducted. In mouse embryonic fibroblasts (MEFs) and embryonic stem cells (mESCs), 89 596 and 115 165 silencers are identified, respectively. These silencers are ubiquitously distributed across the genome and are predominantly associated with low-expression genes. Additionally, these silencers are mainly cell-specific and function by binding to repressive transcription factors (TFs). Further, these silencers are notably enriched with the histone modification H3K9me3. It is observed that the transformation between dual-function silencers and enhancers is correlated with intracellular transcription factor concentrations, accompanied by changes in epigenetic modifications. In terms of biological effects, we have identified silencers that can enhance the induction efficiency of MEFs and influence the pluripotency of mESCs. Collectively, this work offers the first comprehensive silencer landscape in the mouse genome and provides strong evidence for the role of silencers in the induction of induced pluripotent stem cells (iPSCs).

Animals↗

PubMed2025

Spatial transcriptomic analysis of mouse parathyroid gland cells expressing an activating variant of Gcm2.

Glial cells missing 2 (GCM2) is an essential transcription factor for the development of parathyroid glands. Germline GCM2 variants that repress or enhance transcriptional activity predispose a subset of patients to hypoparathyroidism or hyperparathyroidism, respectively. A recurrent germline heterozygous activating missense variant of GCM2, p.Y394S has been identified in some patients with primary hyperparathyroidism. A genetically engineered knock-in mouse model of this variant corresponding to p.Y392S in the mouse Gcm2 gene (Gcm2 +/Y392S) did not show obvious parathyroid tumors. However, in GCM2-binding site mediated luciferase reporter assays in HEK293 cells, the mouse and the human variant both exhibited enhanced transcriptional activity. Therefore, we assessed the effect of this variant on gene expression in vivo in parathyroid glands from Gcm2 +/Y392S and WT mice. Using the 10x Genomics Visium platform, spatially resolved transcriptomic analysis was performed on formalin-fixed and paraffin-embedded (FFPE) tracheal tissue sections of Gcm2 +/Y392S and WT mice to capture RNA from parathyroid glands together with other cell types in the tissue sections. Transcriptome sequence data analysis detected 8 different clusters in the tissue sections based on similarity of gene expression profiles. Cluster-1, which contained parathyroid gland cells expressing Pth and Gcm2, was further evaluated for transcripts that were differentially expressed more than 2-fold in Gcm2 +/Y392S compared to WT. Increased transcript level of Lgals3 (galectin-3) was seen in Gcm2 +/Y392S parathyroid gland cells which is among markers of parathyroid carcinoma. Galectin-3 protein was detected in available FFPE human parathyroid samples of patients with germline heterozygous activating GCM2 variants, p.Y394S (n = 4/10) or p.L379Q (n = 2/2). These results indicate a potential for growth and malignancy of parathyroid glands expressing GCM2 variants. The transcriptomic data of mouse parathyroid gland cells generated in this study can serve as a valuable resource for investigating genes and pathways in normal or abnormal parathyroid gland growth and physiology.

GCM2, gene↗

PubMed2025

Inhaled xenon modulates microglia and ameliorates disease in mouse models of amyloidosis and tauopathy.

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder. Antiamyloid antibody treatments modestly slow disease progression in mild dementia due to AD. Emerging evidence shows that homeostatic dysregulation of the brain immune system, especially that orchestrated by microglia, plays an important role in disease onset and progression. Thus, a major question is how to modulate the phenotype and function of microglia to treat AD. Xenon (Xe) gas is a noble gas used in human patients as an anesthetic and a neuroprotectant used for treating brain injuries. Xe penetrates the blood-brain barrier, which could make it an effective therapeutic. To assess the effect of Xe on microglia and AD pathology, we designed a custom Xe inhalation chamber and treated several mouse models of AD with Xe gas. Xe treatment induced mouse microglia to adopt an intermediate activation state that we have termed pre-neurodegenerative microglia (pre-MGnD). This microglial phenotypic transition was observed in mouse models of acute neurodegeneration and amyloidosis (APP/PS1 and 5xFAD mice) and tauopathy (P301S mice). This microglial state enhanced amyloid plaque compaction and reduced dystrophic neurites in the APP/PS1 and 5xFAD mouse models. Moreover, Xe inhalation reduced brain atrophy and neuroinflammation and improved nest-building behavior in P301S mice. Mechanistically, Xe inhalation induced homeostatic brain microglia toward a pre-MGnD state through IFN-γ signaling that maintained the microglial phagocytic response in APP/PS1 and 5xFAD mice while suppressing the microglial proinflammatory phenotype in P301S mice. These results support the translation of Xe inhalation as an approach for treating AD.

Animals↗

PubMed2025

DHX15 inhibits mouse APOBEC3 deamination.

APOBEC3 family proteins are critical host factors that counteract and prevent the replication of retroviruses and other viruses through cytidine deamination. Human APOBEC3 proteins inactivate HIV-1 through the introduction of lethal mutations to viral genomes. In contrast, mouse APOBEC3 does not induce DNA hypermutation of murine retroviruses, although it retains functional cytidine deaminase activity. Why mouse APOBEC3 does not effectively deaminate murine retroviruses is still unknown. In this study, we found that the dead box helicase DHX15 interacts with mouse APOBEC3 and inhibits its deamination activity. DHX15 was packaged into murine leukemia virus (MLV) virions independent of its binding with APOBEC3. Moreover, DHX15 knockdown inhibited MLV replication and resulted in more G-to-A mutations in proviral DNA. Finally, DHX15 knockdown induced DNA damage in murine cells, suggesting that it plays a role in preserving genome integrity in cells expressing mouse APOBEC3 protein.

Animals↗

PubMed2025

AstroGreen transgenic mouse illuminates the trafficking of astrocyte-derived extracellular vesicles.

Astrocytes interact with neighboring cells by releasing extracellular vesicles (EVs). Tools to study astrocyte EV-mediated communication with other brain cells in vivo are essential. In this study, we crossed the Exomap1 transgenic mouse expressing Cre-activated human-specific CD81 (HsCD81) fused to the fluorescent protein mNeonGreen (HsCD81mNG), to a transgenic mouse expressing Cre under the astrocyte-expressing GFAP promoter resulting in Exomap1::Gfap-Cre mice, referred to here as AstroGreen. We characterized HsCD81mNG-expressing astrocytes and shedded EVs loaded with HsCD81mNG and Cre, both in vitro and in mouse brains. Using this model, we show that HsCD81mNG can be used to track EV content, production, and functional Cre transfer in vitro and in the brain, allowing evaluation of the interaction of astrocytes with neighboring cells mediated by EVs. We anticipate that this model will improve our understanding of astrocytes transferring EVs within their surroundings during normal physiological processes and in the context of neuropathological conditions.

Animals↗

PubMed2026

Alternative transcription of the mouse Gh gene identifies an immune-associated transcript with species-specific structural divergence.

Growth hormone (GH) in mice is primarily expressed in the anterior pituitary, although Gh expression has been reported in extrapituitary tissues, including immune organs. However, the structure of immune-associated Gh transcripts remains poorly characterized. To determine whether splenic Gh transcripts differ from pituitary Gh mRNA, 5'- and 3'-rapid amplification of cDNA ends (RACE) analyses were performed. While 3' RACE showed a shared polyadenylation site, 5' RACE identified a novel exon located approximately 2 kb upstream of the conventional exon 1, generating a transcript (spl-Gh mRNA) with a distinct first exon but shared downstream exons with pituitary Gh mRNA (pit-Gh mRNA). RT-PCR analysis revealed that spl-Gh mRNA is predominantly expressed in immune tissues such as spleen and bone marrow, and its distribution did not correlate with Pit-1 mRNA expression. Quantitative RT-PCR further demonstrated that spl-Gh mRNA was expressed at levels comparable to those of pit-Gh mRNA in the mouse spleen, indicating that spl-Gh is one of the major Gh transcript forms in this tissue. Sequence analysis indicated that spl-Gh mRNA is predicted to retain coding potential for a GH protein. Comparative genomic analyses further demonstrated that genomic features associated with the spl-Gh transcriptional unit are conserved only in a subset of closely related Mus species. In contrast, although a spl-Gh-related transcript was detected in rat spleen, no properly spliced mouse-like transcript was identified under the present experimental conditions. The detected transcript exhibited intron retention and an in-frame stop codon, suggesting that it is unlikely to produce a functional GH protein. These findings identify a distinct immune-associated Gh transcript generated through alternative transcription of the mouse Gh gene and suggest that immune-associated Gh transcriptional mechanisms have undergone species-specific divergence among rodents. Together, these findings reveal previously unrecognized complexity in Gh gene regulation and highlight species-specific differences in immune-associated Gh transcripts.

Animals↗

PubMed2026

Generation of a novel Slc7a9G105R mutant mouse identifies new biomarkers for cystinuria.

INTRODUCTION: Cystinuria is a rare inherited disease characterized by increased urinary cystine levels resulting in the formation of cystine stones in the urinary tract. Mutations in the genes encoding the cystine transporter complex, SLC3A1 and SLC7A9, are the primary drivers of the disease. Current mouse models used to study cystinuria rely on gene deficiency or spontaneous mutations in mice that do not accurately reflect the pathogenic mutations found in humans. METHODS: We generated a novel Slc7a9G105R knock-in mouse model in which glycine at position 105 is replaced by arginine, recapitulating the most common pathogenic mutation in human SLC7A9. Disease onset and progression were assessed using micro-CT imaging, fecal metagenomics, and urine and serum metabolomics and proteomics. RESULTS: Both male and female Slc7a9G105R mice developed a cystinuria phenotype by nine weeks of age, characterized by substantial cystine stone formation and increased urinary cystine, lysine, arginine, and ornithine. Slc7a9G105R mice displayed distinct serum and urinary metabolite profiles, mapped to dibasic amino acid pathways, and serum protein profiles, mapped to disease progression. Fecal metagenomics revealed that Slc7a9G105R mice had a heterogeneous microbiota with altered functional pathways, including increased L-cysteine biosynthesis. Antibiotic-induced depletion of the microbiota did not affect cystine stone burden but reduced urinary tract inflammation. Prophylactic or therapeutic dietary supplementation with alpha-lipoic acid reduced stone burden and inflammation, but it also caused urothelial damage. Untargeted metabolomics analysis following alpha-lipoic acid supplementation identified metabolites that can increase cystine solubility, reduce inflammation, and damage epithelial cells. Correlation analysis revealed novel serum metabolite biomarkers of stone burden, including 2-hydroxybutyric acid and 2-amino-2-thiazoline-4-carboxylic acid, which were also detected in human serum. CONCLUSIONS: Collectively, the Slc7a9G105R mutant mouse model offers a precise, rapid-onset, and translational platform for investigating cystinuria pathogenesis and evaluating potential therapeutic strategies.

SLC7A9↗

PubMed2024

Retinal Proteome Profiling of Inherited Retinal Degeneration Across Three Different Mouse Models Suggests Common Drug Targets in Retinitis Pigmentosa.

Inherited retinal degenerations (IRDs) are a leading cause of blindness among the population of young people in the developed world. Approximately half of IRDs initially manifest as gradual loss of night vision and visual fields, characteristic of retinitis pigmentosa (RP). Due to challenges in genetic testing, and the large heterogeneity of mutations underlying RP, targeted gene therapies are an impractical largescale solution in the foreseeable future. For this reason, identifying key pathophysiological pathways in IRDs that could be targets for mutation-agnostic and disease-modifying therapies (DMTs) is warranted. In this study, we investigated the retinal proteome of three distinct IRD mouse models, in comparison to sex- and age-matched wild-type mice. Specifically, we used the Pde6βRd10 (rd10) and RhoP23H/WT (P23H) mouse models of autosomal recessive and autosomal dominant RP, respectively, as well as the Rpe65-/- mouse model of Leber's congenital amaurosis type 2 (LCA2). The mice were housed at two distinct institutions and analyzed using LC-MS in three separate facilities/instruments following data-dependent and data-independent acquisition modes. This cross-institutional and multi-methodological approach signifies the reliability and reproducibility of the results. The large-scale profiling of the retinal proteome, coupled with in vivo electroretinography recordings, provided us with a reliable basis for comparing the disease phenotypes and severity. Despite evident inflammation, cellular stress, and downscaled phototransduction observed consistently across all three models, the underlying pathologies of RP and LCA2 displayed many differences, sharing only four general KEGG pathways. The opposite is true for the two RP models in which we identify remarkable convergence in proteomic phenotype even though the mechanism of primary rod death in rd10 and P23H mice is different. Our data highlights the cAMP and cGMP second-messenger signaling pathways as potential targets for therapeutic intervention. The proteomic data is curated and made publicly available, facilitating the discovery of universal therapeutic targets for RP.

Animals↗

PubMed2026

Targeted insertion of an optimized donor DNA is effective in a humanized mouse model of dominant retinitis pigmentosa.

Retinitis pigmentosa (RP) affects 1 in 3,000 individuals worldwide, with 30%-40% of cases inherited as autosomal dominant (AD). Mutations in RHO (RP4) are the most common cause of ADRP. Because most RHO mutations exert gain-of-function or dominant-negative effects, conventional gene supplementation is insufficient, requiring mutant allele inactivation. Allele-specific editing is impractical, as each mutation requires a unique therapeutic strategy. We present a mutation-agnostic, RHO-specific approach using adeno-associated viral vector-mediated homology-independent targeted integration (AAV-HITI). Optimized donor DNA design enables targeted integration and efficient transgene expression from the endogenous RHO locus. In a humanized RP4 mouse model harboring the RHO P23H mutant allele alongside an endogenous wild-type mouse Rho allele, AAV-HITI significantly improves retinal structure, function, and visual acuity up to 1 year post-treatment. Comprehensive molecular analyses characterize on-target editing in mouse retina and off-target editing in a human cell line. These findings establish an effective, human-centric AAV-HITI platform for RP4 and support its evaluation in this and other dominant genetic conditions.

AAV↗

PubMed2026

Proinsulin regulators identified with CRISPR screen and in vivo mouse QTL mapping.

Altered proinsulin levels in β-cells and bloodstream are hallmarks of diabetes and other diseases, but our knowledge about the proinsulin regulators remains limited. Here we perform a genome-wide CRISPR screen to identify 84 proinsulin regulators that alter intracellular proinsulin/insulin ratio in a mouse β-cell line. The proinsulin regulators are distinct from the insulin regulators from a previous orthogonal CRISPR screen. Functional annotation of the proinsulin regulators highlights Golgi as the primary organelle for proinsulin storage and regulation. Trafficking towards the Golgi increases the intra-cellular proinsulin/insulin ratio, while trafficking away from the Golgi, including exocytosis and Golgi-to-ER retrograde transport, decreases the intracellular proinsulin levels. We also map mouse quantitative trait loci (QTLs) associated with plasma proinsulin levels and use the CRISPR screen results to pinpoint the causal genes within the QTL loci. Interestingly, protein disulfide isomerase Pdia6 is the strongest hit from both CRISPR screen and the in vivo QTL mapping. Knocking down Pdia6 significantly reduce proinsulin accumulation in Golgi and secretory granules. Intriguingly, Pdia6-depletion in both human and mouse β-cells does not affect the folding status of proinsulin but causes significantly impaired proinsulin production through a UPR-independent mechanism. Taken together, our genetic profiles provide mechanistic insights into the regulation of proinsulin/insulin homeostasis.

Animals↗

PubMed2024

A novel mouse model recapitulates the effects of rs2254524 variant in the lanosterol synthase gene on salt sensitivity and organ damage.

OBJECTIVE: The blood pressure (BP) response to salt intake (salt sensitivity) shows great variability among individuals and is more frequent in hypertensive patients. Elevated levels of the steroid hormone Endogenous Ouabain (EO) are associated with hypertension (HT) and salt sensitivity. The lanosterol synthase gene ( LSS ) plays a key role in the biosynthesis of steroids and its rs2254524 variant (Val642Leu) is linked to salt sensitivity in humans. This study aims to investigate the pathophysiological significance of the Lss missense variation in a new knock-in mouse model of salt-sensitive HT onset. METHODS: We generated a mouse model carrying the murine homolog (Val643Leu) of the human LSS variant. C57BL/6N LssV643L/V643L mice were fed different NaCl diets (low-salt, LSD; normal-salt, NSD; high-salt, HSD) and were characterized at functional, histological, and molecular levels. RESULTS: At baseline, mutant mice showed an enlarged kidney compared to the wild-type (WT) counterpart, but the Lss V643L variant did not affect EO biosynthesis nor systolic BP at 3 and 12 months. In HSD, we observed an increased systolic BP only in 12-month-old LssV643L/V643L mice, compared to NSD. Moreover, only the HSD LssV643L/V643L mice showed cardiac hypertrophy and a higher incidence of cardiac fibrosis compared to WT at 12 months. Finally, the Lss mRNA level was differentially regulated by HSD in the adrenal gland, liver, and heart of LssV643L/V643L mice compared to WT. CONCLUSIONS: The novel Lss mouse model resembles the salt-sensitive HT phenotype observed in hypertensive patients and provides a good model of salt-sensitive HT and HT-mediated organ damage.

Animals↗

PubMed2026

A dual-reporter mouse for therapeutic discovery in Angelman syndrome.

Angelman syndrome is a neurodevelopmental disorder caused by loss of the maternal UBE3A allele, the sole source of UBE3A in mature neurons owing to epigenetic silencing of the paternal allele. Although emerging therapies are being developed to restore UBE3A expression by activating the dormant paternal UBE3A allele, existing mouse models for such preclinical studies have limited throughput and utility, creating bottlenecks for both in vitro therapeutic screening and in vivo characterization. To address this, we developed the Ube3a-INSG dual-reporter knockin mouse, in which an IRES-Nanoluciferase-T2A-Sun1-sfGFP (INSG) cassette was inserted downstream of the endogenous Ube3a stop codon. The INSG model preserves UBE3A protein levels and function while enabling 2 complementary allele-specific readouts: Sun1-sfGFP and Nanoluciferase. We show that Sun1-sfGFP, a nuclear envelope-localized reporter, enables single-cell fluorescence analysis, whole-brain light-sheet imaging, and nuclear quantification by flow cytometry. Further, Nanoluciferase supports high-throughput luminescence assays for sensitive pharmacological profiling in cultured neurons and noninvasive in vivo bioluminescence imaging for pharmacodynamic assessment. By combining scalable screening, cellular analysis, and real-time in vivo monitoring in a single model, the Ube3a-INSG dual-reporter mouse provides a powerful platform to accelerate therapeutic development centered on UBE3A.

Animals↗

PubMed2026

Loss of maternal PADI6 disrupts DNA methylation and genomic imprinting maintenance in late preimplantation mouse embryos.

BACKGROUND: The maternal-effect protein PADI6, which is part of the subcortical maternal complex, is involved in proper spindle assembly, organelle distribution, ribosome storage, and cytoplasmic lattice organization in mouse oocytes. In humans, variants of PADI6 are associated with female infertility and multilocus imprinting disturbance in offspring. Recently, it was demonstrated that PADI6 plays a role in the storage and cytoplasmic localization of epigenetic factors, including UHRF1 and DNMT1. Moreover, maternal PADI6 depletion leads to defective epigenetic reprogramming and zygotic genome activation but not to an imprinting defect in two-cell mouse embryos. These findings raise the possibility that imprinting disturbances arise later in development. RESULTS: By employing combined single-blastocyst RNA-seq/BS-seq and immunostaining validation in the embryos derived from Padi6P620A-mutant oocytes, we investigated the role of Padi6 in late preimplantation development. We demonstrated that embryos that overcame the two-cell stage block had a dramatic reduction in UHRF1 and DNMT1 protein levels, a decrease in H3K9me3, and whole-genome hypomethylation, including most imprinted loci and repetitive elements, at the blastocyst stage. Furthermore, these maternal mutant embryos showed deregulation of inner cell mass markers and defective blastocyst implantation, but no effect on trophoblast differentiation. CONCLUSION: Our results demonstrate that maternal PADI6 is a key regulator of the stability of epigenetic factors required to maintain repressive marks in late preimplantation mouse embryos. Its deficiency results in genomic imprinting defects that closely resemble those found in human patients and provide a mechanistic explanation for MLID caused by maternal PADI6 variants. Furthermore, the impairment of blastocyst implantation capacity, likely due to dysregulation of inner cell mass differentiation, provides new mechanistic insights into the control of female fertility and embryo development exerted by PADI6.

DNA Methylation↗

PubMed2026

TRIM28 regulates the G2/M transition via histone modification and DNA damage repair during mouse oocyte meiosis.

TRIM28, a member of the tripartite motif (TRIM) family, functions as a transcriptional coregulator involved in maintaining genome stability during mitosis. In this study, we explored the role of TRIM28 in mouse oocyte meiotic maturation, where transcriptional activity is barely detectable. We found that TRIM28 was constitutively expressed during the early stages of oocyte meiotic maturation, with predominant nuclear localization in germinal vesicle (GV)-stage oocytes. TRIM28 depletion caused defective germinal vesicle breakdown (GVBD), but oocytes that successfully underwent GVBD displayed unimpaired first polar body (PB1) extrusion. TRIM28 depletion impaired CDK1 activity and reduced cyclin B1 levels, leading to a delay in the G2/M transition. This delay might be caused by altered levels of HDAC2-mediated H4K12ac and H3K4me2-modulated H3K9me2 in nonsurrounded nucleolus (NSN)-type GV oocytes, which decreased transcription activity. Additionally, TRIM28-depleted oocytes exhibited elevated γ-H2A.X expression, accompanied by aberrant expression of CHK1 and CHK2, as well as dysregulated expression of RAD51, which collectively contributed to GVBD failure in mouse oocytes. In conclusion, our findings indicate that TRIM28 participates in the regulation of the G2/M transition during mouse oocyte meiotic maturation, acting through the modulation of histone modifications and DNA damage repair.

Animals↗