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PubMed2026

Proteomic signatures of adipocyte recruitment in breast cancer.

The tumor microenvironment (TME) is increasingly recognized as a dynamic regulator of breast cancer progression, with adipocytes functioning as active contributors rather than passive bystanders. Here, we investigated the proteomic and morphologic reprogramming of breast cancer-associated adipocytes (BrCAAs) in response to triple-negative breast cancer (TNBC). Using conditioned medium from HCC1143 cells, we established an in vitro BrCAA model and performed mass spectrometry-based proteomics. Comparative profiling revealed 256 differentially expressed proteins, enriched for pathways including fatty acid degradation, carbon metabolism, and glycogen turnover, consistent with a metabolic shift from energy storage to energy supply. Gene ontology and protein-protein interaction analyses further identified cytoskeletal remodeling, adhesion dynamics, and secretory pathway activation, supporting BrCAA-driven microenvironmental remodeling. In the MMTV-PyMT mouse model, morphometric analysis demonstrated progressive size reduction and increased contour irregularity of adipocytes adjacent to tumors, correlating with proteomic evidence of metabolic stress. Importantly, BrCAAs localized at tumor interfaces were associated with increased microvessel density and CD105+ endothelial activation compared to desmoplastic zones. Proteomic enrichment highlighted pro-angiogenic remodeling, with validation of basigin (BSG), integrin αV (ITGAV), and 2,4-dienoyl-CoA reductase 1 (DECR1). Collectively, our findings establish BrCAAs as metabolically and structurally reprogrammed stromal components that promote tumor metabolism and localized angiogenesis, representing potential therapeutic targets in aggressive breast cancer.

Female↗
PubMed2026

Efferocytosis regulatory factors in atherosclerosis: A preclinical systematic review.

BACKGROUND: Impaired efferocytosis is a key driver of plaque instability during atherosclerosis progression. Efficient clearance of apoptotic cells through efferocytosis relies on the coordinated action of multiple regulatory factors. METHODS: PubMed, Web of Science, ScienceDirect, OVID MEDLINE, and Scopus were searched for studies published up to February 7, 2026. Eligible preclinical studies were systematically reviewed to identify endogenous factors that regulate efferocytosis in atherosclerosis. Clinical evidence was also incorporated to enable a preliminary translational assessment of these regulatory factors. RESULTS: Thirty-five endogenous regulatory factors were identified from 36 included studies, and their functional roles across distinct stages of efferocytosis were characterized. Notably, metabolic regulators such as PKM2, PFKFB3, GLS1, and Drp1 were involved in distinct efferocytosis stages. This suggests that metabolic reprogramming may provide the metabolic support require for efficient efferocytosis and inflammation resolution. Ten factors were supported by preliminary clinical evidence consistent with preclinical data. PKM2 was the only candidate biomarker with prospective observational data. However, its independent predictive value still requires validation in multicenter prospective studies. CONCLUSIONS: This review provides a systematic synthesis of 35 endogenous efferocytosis regulators and elucidates their regulatory network in atherosclerosis based on a functional stage framework. Metabolic reprogramming is identified as a central hub linking efferocytosis efficiency to inflammation resolution. This review offers a new theoretical basis for efferocytosis-targeted intervention strategies.

Animals↗
PubMed2026

Maternal transfer of nonylphenol drives oxidative, immune, and epigenetic dysregulation in zebrafish offspring.

Nonylphenol (NP), a widespread surfactant and endocrine-disrupting pollutant, poses significant ecological and public health risks globally; however, its transgenerational effects remain poorly understood. Using zebrafish (Danio rerio), we compared chronic maternal NP exposure (50 and 100 µg/L, 28 days) with acute embryonic exposure (0.22 µmol/L) during 0-3 days post-fertilization (dpf) to delineate mechanistic differences in toxicity. Maternal NP exposure produced severe developmental defects in offspring, including edema, axial curvature, impaired swim bladder inflation, reduced growth, cardiac dysfunction, and decreased viability. These phenotypes were accompanied by systemic molecular disruptions including oxidative stress, altered estrogen receptor (ER) expression, dysregulated mitogen-activated protein kinase (MAPK) signaling, and suppressed innate immune response characterized by attenuated neutrophil/macrophage density, reduced CD68 and complement protein C3 expression, diminished nitrite load, and downregulation of pro-inflammatory mediators at both transcript and protein levels. Maternal exposure further induced apoptosis and persistent epigenetic reprogramming (alterations in DNA methylation and histone-modifying enzymes), hallmarks of transgenerational toxicity. In contrast, direct embryonic NP exposure elicited morphological abnormalities without significant lethality, accompanied by induction of pro-inflammatory cytokines, nitric oxide (NO) synthesis, and MAPK activation, reflecting an augmented inflammatory response. These mechanistic contrasts reveal that maternal NP exposure is a potent driver of systemic, heritable molecular reprogramming, whereas embryonic exposure triggers acute inflammatory pathways. Together, our findings underscore the global relevance of NP as a transgenerational toxicant, advocating for its urgent inclusion in ecotoxicological risk assessments and regulatory frameworks.

Animals↗
PubMed2026

Matrix Mechanics Governs Mechano-Metabolic Adaptation across Cancer Grades in Bladder Spheroids.

Extracellular matrix (ECM) mechanics is pivotal regulators of tumor progression, yet how viscoelasticity and matrix architecture converge to shape metabolic and invasive adaptation remains insufficiently defined. We postulate that mechanical stimuli from the ECM induce coordinated changes in adhesive and metabolic pathways, and that the nature of this independent mechano-metabolic pathway is conserved across benign, low-invasive, and high-invasive bladder cancer phenotypes. Therefore, we engineered collagen-hyaluronan hydrogels with tunable stiffness to recapitulate soft and rigid tumor microenvironments and profiled bladder cancer spheroids representing benign, low-invasive, and highly invasive states. Integrating hydraulic force spectroscopy, rheology, and molecular phenotyping, we show that matrix stiffening differentially reprograms spheroid architecture, motility, and adhesion- and metabolism-related gene expression. Spheroid behavior emerged from the interplay between intrinsic mechanical properties, matrix rheology, and molecular adaptation. HCV29 spheroids formed rigid, compact structures, relying on cell-matrix adhesion rather than metabolic or proteolytic remodeling. HT1376 spheroids activated glycolysis (HK2) and MMP-2-dependent ECM remodeling in soft matrices, but remained largely nonmigratory, indicating decoupling of invasive priming from motility. T24 spheroids were soft, deformable, and highly migratory in compliant matrices, integrating metabolic reprogramming, adhesion remodeling (E-/N-cadherin, SDC4), and radial collagen fiber alignment to drive invasion. Notably, canonical FAK/AKT/mTOR signaling was absent across all spheroids, while pS6 ribosomal protein and ILK indicated noncanonical, SDC4/integrin-ILK-dependent mechanotransduction supporting cytoskeletal dynamics, metabolism, and ECM remodeling. Collagen organization further differed across spheroid types, with dense, radially aligned fibers in HT1376, intermediate architecture in HCV29, and loose, disorganized networks in T24, closely matching their distinct migratory behaviors and cell-ECM interactions. These findings reveal stage-specific mechanometabolic strategies in bladder cancer, demonstrating how ECM mechanics and architecture jointly guide invasion, metabolic adaptation, and local immune modulation, including the regulation of immune cell infiltration and tumor immune evasion.

Humans↗
PubMed2026

Multimodal Analysis Reveals Aberrant Expression of SUMO2 and Its Significant Association With Key Mechanisms of Metabolic Pathways in Hepatocellular Carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide. However, the role of small ubiquitin-like modifier 2 (SUMO2), a core member of the small ubiquitin-like modifier (SUMO) family, regarding its expression patterns and metabolism-related functions in HCC remains inadequately understood. METHODS: A multidimensional analytical framework was applied, integrating immunohistochemistry (153 HCC vs. 21 non-HCC samples), proteomics (159 paired samples), bulk transcriptomics (3240 HCC vs. 2267 non-HCC samples), single-cell RNA sequencing (RNA-seq) (10 HCC vs. 8 non-HCC samples), spatial transcriptomics, and external CRISPR/Cas9 functional genomics data. Systematic analyses included standardized mean difference (SMD), pathway enrichment, pseudotime trajectory inference, in silico knockout, cell-cell communication, metabolic flux scoring, immune infiltration, clinical correlation, drug sensitivity prediction, and molecular docking. RESULTS: At the protein level, immunohistochemistry (nuclear positivity) and external proteomic data collectively demonstrated consistent SUMO2 overexpression in HCC. Consistent upregulation was also observed at the mRNA level across large-scale cohorts. Single-cell RNA-seq and spatial transcriptomics localized SUMO2 enrichment to malignant hepatocytes and tumor-dominant regions. CRISPR-mediated SUMO2 knockout suppressed proliferation in multiple HCC cell lines. Mechanistically, high SUMO2 expression was significantly associated with metabolic reprogramming involving glycolysis/gluconeogenesis, pyruvate metabolism, and the tricarboxylic acid cycle. SUMO2-high malignant hepatocyte subpopulations exhibited enhanced activity of the macrophage migration inhibitory factor signaling axis and enhanced iron-sensor interactions. Further, the immune infiltration analysis revealed a negative correlation between SUMO2 expression and M1 macrophages and a positive correlation between follicular helper T cells and regulatory T cells. Clinically, elevated SUMO2 levels were found to be associated with adverse prognostic features. Furthermore, high SUMO2 expression was associated with increased sensitivity to dasatinib, and molecular docking simulations predicted potential binding between SUMO2 and dasatinib, with a Vina score of -8.5 kcal/mol. CONCLUSIONS: SUMO2 is aberrantly expressed at the protein, mRNA, single-cell, and spatial transcriptomic levels in HCC and is significantly associated with metabolic reprogramming and altered migration inhibitory factor (MIF)-mediated intercellular communication, suggesting its potential as a novel biomarker for diagnosis and treatment.

Humans↗
PubMed2026

Induced Pluripotent Stem Cells in Non-Model Species: Applications and Challenges.

Induced pluripotent stem cells have revolutionized biomedical research-yet the vast majority of life on Earth remains beyond their reach. Non-model species lack the annotated genomes, validated reagents, and species-specific culture infrastructure that make iPSC technology routine in humans and mice, and this infrastructure deficit, compounded by genuine biological differences in pluripotency network architecture across taxa, is what has kept the field narrow. The deep conservation of the core pluripotency network across vertebrates suggests that reprogramming may, in principle, be achievable across a far broader range of species than currently demonstrated-though the extent to which this holds across more divergent taxa remains to be established. This review consolidates current progress and future potential of iPSC technology across five domains: technical reprogramming challenges and advances; conservation applications including genetic rescue, in vitro gametogenesis, and de-extinction; medical applications within a one medicine framework; agricultural applications spanning disease resistance, climate resilience, and cultured meat; and species-specific iPSC-derived systems in ecotoxicology. Throughout, we distinguish what has been demonstrated from what remains aspirational and identify the priorities that will determine whether the iPSC revolution can be extended-rigorously and at scale-beyond model organism research.

Induced Pluripotent Stem Cells↗
PubMed2026

Enzyme-Metabolite Network Analysis of Endometrial Cancer-Derived Extracellular Vesicles Through Integrated Proteomics and Metabolomics.

Endometrial cancer (EC) is the most common gynecological malignancy in high-income countries. Extracellular vesicles (EVs) are key mediators of intercellular communication and metabolic reprogramming, but their molecular cargo in EC remains poorly characterized. EVs were isolated from four EC cell lines representing Type I and Type II subtypes (AN3CA, ISHIKAWA, HEC1A, and KLE). Untargeted metabolomics was performed by HILIC-LC-MS/MS, proteomics by data-independent acquisition (DIA) mass spectrometry, and multi-omics integration using MetaboAnalyst and OmicsNet. Metabolomic profiling identified 1463 annotated features and revealed significant differences among EC cell lines (PERMANOVA, p = 0.002). Twenty-eight differentially abundant metabolites, including lactic acid, succinic acid, and uric acid, were identified. Proteomic analysis quantified 8513 proteins with subtype-specific expression patterns. Integrated analysis revealed seven significantly enriched pathways, including glycolysis/gluconeogenesis, central carbon metabolism in cancer, and the pentose phosphate pathway. Increased LDHA abundance in metastatic AN3CA-derived EVs was confirmed by Western blot (p = 0.047). EC-derived EVs display subtype- and metastatic-status-specific metabolo-proteomic signatures, with glycolysis, TCA cycle remodeling, and central carbon metabolism as convergent pathway signatures of molecular reprogramming. These findings establish a multi-omics framework for characterizing EV cargo in EC and identify candidate enzyme-metabolite nodes for future biomarker validation in patient-derived specimens.

Female↗
PubMed1997

Regulation of gene expression in the preimplantation mouse embryo: temporal and spatial patterns of expression of the transcription factor Sp1.

Activation of the embryonic genome during preimplantation mouse development entails a dramatic reprogramming of the pattern of gene expression. The complement of transcription factors that are present in the early embryo and that must intrinsically be involved in this reprogramming is essentially uncharacterized. We and others have demonstrated that transcription factor Sp1 is present in the mouse oocyte and early cleavage stage preimplantation embryo. Due to Sp1's prominent role in regulating the expression of a vast array of genes that are involved in cell proliferation and differentiation, as well as in general housekeeping functions, we characterized the temporal and spatial patterns of Sp1 expression during preimplantation development. The relative abundance of Sp1 transcripts, as well as transcripts for the TATA box-binding protein TBP, decreases during oocyte maturation and reaches a minimum level in the two-cell stage, after which time the abundance of these transcripts increases progressively to the blastocyst stage. Immunoblotting experiments detect Sp1 species of Mr = 95,000 and 105,000 at all stages of preimplantation development. The amount of Sp1 increases about 8-fold during preimplantation development, and an alpha-amanitin-insensitive increase is observed between G1 and G2 of the one-cell embryo; this increase may reflect the mobilization of a maternal Sp1 transcript. Immunocytochemical experiments also reveal a similar increase in the amount of Sp1 during preimplantation; the nuclear concentration of Sp1 is greater in the trophectoderm cells than in the inner cell mass cells. Finally, gel-shift experiments document an increase during preimplantation development of a DNA-binding activity that is likely due to Sp1. These increases in the abundance of the Sp1 protein and an Sp1-like DNA-binding activity parallel increases in the rate of transcription that occur during preimplantation development.

Animals↗
PubMed1999

Nucleolar ultrastructure in bovine nuclear transfer embryos.

Nuclear transfer experiments in mammals have attempted to reprogram a donor nucleus to a state equivalent to the zygotic one. Reprogramming of the donor nucleus is, among other features, indicated by a synthesis of ribosomal RNA (rRNA). The initiation of rRNA synthesis is simultaneously reflected in nuclear morphology as a transformation of the nucleolus precursor body into a functional rRNA synthesising nucleolus with a characteristic ultrastructure. We examined nucleolar ultrastructure in bovine in vitro produced (control) embryos and in nuclear transfer embryos reconstructed from a MII phase (nonactivated) or S phase (activated) cytoplasts. Control embryos were fixed at the two-, four-, early eight- and late eight-cell stages; nuclear transfer embryos were fixed at 1 and 3 hr post fusion and at the two-, four-, and eight-cell stages. Control embryos possessed a nucleolar precursor body throughout all three cell cycles. In the eight-cell stage embryo, a primary vacuole appeared as an electron lucid area originating in the centre of the nucleolar precursor body. In nuclear transfer embryos reconstructed from nonactivated cytoplasts, the nuclear envelope was fragmented or completely broken down at 1 hr after fusion and, by 3 hr after fusion, it was restored again. At this time, the reticulated fibrillo-granular nucleolus had an almost round shape. The nucleolar precursor body seen in the two-cell stage nuclear transfer embryos consisted of intermingled filamentous components and secondary vacuoles. A nucleolar precursor body typical for the two-cell stage control embryos was never observed. None of the reconstructed embryos of this group reached the eight-cell stage. Nuclear transfer embryos reconstructed from activated cytoplasts, in contrast, exhibited a complete nuclear envelope at all time intervals after fusion. In the two-cell stage nuclear transfer embryo, the originally reticulated nucleolus of the donor blastomere had changed into a typical nucleolar precursor body consisting of a homogeneous fibrillar structure. A primary vacuole appeared in the four-cell stage nuclear transfer embryos, which was one cell cycle earlier than in control embryos. Only nuclear transfer embryos reconstructed from activated cytoplasts underwent complete remodelling of the nucleolus. The reorganisation of the donor nucleolar architecture into a functionally active nucleolus was observed as early as in the four-cell stage nuclear transfer embryo. These ultrastructural observations were correlated with our autoradiographic data on the initiation of RNA synthesis in nuclear transfer embryos.

Animals↗
PubMed2001

DNA methylation and mammalian epigenetics.

Epigenetic modifications of DNA such as methylation are important for genome function during development and in adults. DNA methylation has central importance for genomic imprinting and other aspects of epigenetic control of gene expression, and during development methylation patterns are largely maintained in somatic lineages. The mammalian genome undergoes major reprogramming of methylation patterns in the germ cells and in the early embryo. Some of the factors that are involved both in maintenance and in reprogramming, such as methyltransferases, are being identified. Epigenetic changes are likely to be important in animal cloning, and influence the occurrence of epimutations and of epigenetic inheritance. Environmental factors can alter epigenetic modifications and may thus have long lasting effects on phenotype. Epigenetic engineering is likely to play an important role in medicine in the future.

Animals↗
PubMed1999

Planning and executing an action in Parkinson's disease.

We evaluated the possible impairment in planning and executing an action in patients with Parkinson's disease (PD). The action considered in the present study was formed by two successive motor acts: reaching-grasping an object (first target) and placing it on a second target of the same shape and size. We examined the effects of extrinsic properties of the second target (that is, distance) on the various kinematic phases of reaching-grasping movements. Distance, position, and size of both stimuli were randomly varied across the experimental session. Movements were executed with and without visual control of both targets and arm. The performance of six patients with PD was compared with an age-matched control group. The kinematics of the initial phase of reaching was influenced by position and size of the first target and by distance of the second target in both patients and control subjects. In particular, peak acceleration was higher for farther position of the second target. However, in the subsequent phase patients, differently from control subjects, removed the effects of the second target distance by modifying their reaching kinematics. This was obtained by varying the duration of the acceleration phase. In summary, the patients reprogrammed the reaching component by taking into account only the properties of the first target. The decreasing influence of second-target distance on reaching kinematics of patients was more evident during movements executed under visual control. Moreover, their movements executed without visual control were slowed down from the beginning. The second target affected the grasping kinematics only of the control subjects. Globally, these results indicate that PD patients are able to compute the general program of an action that takes into account extrinsic properties of the final target. However, the finding that PD patients reprogrammed the movement during its execution suggests a decay of the program during its time course, that is, basal ganglia can be involved in storing the plan of an action and in controlling its correct execution.

Adult↗
PubMed2004

Prolegomena to future experimental efforts on genetic code engineering by expanding its amino acid repertoire.

Protein synthesis and its relation to the genetic code was for a long time a central issue in biology. Rapid experimental progress throughout the past decade, crowned with the recently elucidated ribosomal structures, provided an almost complete description of this process. In addition important experiments provided solid evidence that the natural protein translation machinery can be reprogrammed to encode genetically a vast number of non-coded (i.e. noncanonical) amino acids. Indeed, in the set of 20 canonical amino acids as prescribed by the universal genetic code, many desirable functionalities, such as halogeno, keto, cyano, azido, nitroso, nitro, and silyl groups, as well as C=C or C[triple bond]C bonds, are absent. The ability to encode genetically such chemical diversity will enable us to reprogram living cells, such as bacteria, to express tailor-made proteins exhibiting functional diversity. Accordingly, genetic code engineering has developed into an exciting emerging research field at the interface of biology, chemistry, and physics.

Amino Acids↗
PubMed1989

Transfer of dorsoventral information from mesoderm to ectoderm at the onset of limb development.

Control of dorsoventral patterns in the chick at the prelimb stages resides in the limb mesoderm. Recombination experiments at stage 14, with dorsoventrally reversed ectoderm, result in wings with mesodermal dorsoventral polarity. Similar recombinations at stage 16 show that the ectoderm has acquired dorsoventral information and can impose this polarity on the patterns of mesodermal differentiation in the distal regions of the wing. The dorsoventral information in the ectoderm comes from the mesoderm, which transfers this information to the overlying ectoderm between stages 14 and 16. The initial dorsoventral overlying ectoderm between stages 14 and 16. The initial dorsoventral information in the ectoderm is not stable and can be reprogrammed by stage 14 mesoderm. Subsequently, there is a gradual stabilization of the ectodermal information. At the same time the mesoderm loses its capacity to reprogram dorsoventral information in the ectoderm.

Animals↗
PubMed2005

Birth of mice produced by germ cell nuclear transfer.

That mammals can be cloned by nuclear transfer indicates that it is possible to reprogram the somatic cell genome to support full development. However, the developmental plasticity of germ cells is difficult to assess because genomic imprinting, which is essential for normal fetal development, is being reset at this stage. The anomalous influence of imprinting is corroborated by the poor development of mouse clones produced from primordial germ cells (PGCs) during imprinting erasure at embryonic day 11.5 or later. However, this can also be interpreted to mean that, unlike somatic cells, the genome of differentiated germ cells cannot be fully reprogrammed. We used younger PGCs (day 10.5) and eventually obtained four full-term fetuses. DNA methylation analyses showed that only embryos exhibiting normal imprinting developed to term. Thus, germ cell differentiation is not an insurmountable barrier to cloning, and imprinting status is more important than the origin of the nucleus donor cell per se as a determinant of developmental plasticity following nuclear transfer.

Animals↗
PubMed1990

Nuclear transplantation in the pig embryo: nuclear swelling.

The transfer of nuclei from cleavage stage embryos to enucleated activated meiotic metaphase II oocytes results in a reprogramming of the transferred nucleus such that it behaves as a zygotic nucleus. One estimator of nuclear reprogramming is nuclear swelling after nuclear transfer. The diameter of nuclei after nuclear transfer was not found to be dependent upon the amount of cytoplasm transferred with the donor cell or the amount of cytoplasm in the recipient cell. Nuclei from 4-, 8-, and 16-cell stage embryos swelled to a similar diameter after nuclear transfer (26.9, 27.3, and 27.2 microns, respectively) and this was significantly different from the diameter of contemporary donor embryos (18.3, 14.3, and 13.0 microns, respectively). This is a swelling of 47, 91, and 109%, respectively. Since the degree of nuclear swelling does not appear to be related to cytoplasmic volume it is concluded that the components mediating nuclear swelling are not in a limiting supply.

Animals↗
PubMed2004

Dual-regulated myoD- and msx1-based interventions in C2C12-derived cells enable precise myogenic/osteogenic/adipogenic lineage control.

BACKGROUND: Advanced gene therapy, tissue engineering and biopharmaceutical manufacturing require sophisticated and well-balanced multiregulated multigene interventions to reprogram desired mammalian cell phenotypes. METHODS: We have combined the streptogramin (PIP)- and tetracycline (TET)-responsive gene regulation systems for independent expression control of the differentiation determinants myoD and msx1 in C2C12-derived cells. RESULTS: Different dual-regulated expression scenarios which induce either both, only one or none of the lineage control genes triggered differential differentiation and precise control of myogenic, osteogenic or adipogenic cell phenotypes. CONCLUSIONS: Our findings substantiate the use of multiregulated multigene interventions in reprogramming cellular differentiation pathways in a desired manner.

Adipocytes↗
PubMed2002

Differential cytoplast requirement for embryonic and somatic cell nuclear transfer in cattle.

Effective activation of a recipient oocyte and its compatibility with the nuclear donor are critical to the successful nuclear reprogramming during nuclear transfer. We designed a series of experiments using various activation methods to determine the optimum activation efficiency of bovine oocytes. We then performed nuclear transfer (NT) of embryonic and somatic cells into cytoplasts presumably at G1/S phase (with prior activation) or at metaphase II (MII, without prior activation). Oocytes at 24 hr of maturation in vitro were activated with various combinations of calcium ionophore A23187 (A187) (5 microM, 5 min), electric pulse (EP), ethanol (7%, 7 min), cycloheximide (CHX) (10 micro g/ml, 6 hr), and then cultured in cytochalasin D (CD) for a total of 18 hr. Through a series of experiments (Exp. 1-4), an improved activation protocol (A187/EP/CHX/CD) was identified and used for comparison of NT efficiency of embryonic versus somatic donor cells (Exp. 5). When embryonic cells from morula and blastocysts (BL) were used as nuclear donors, a significantly higher rate of blastocyst development from cloned embryos was obtained with G1/S phase cytoplasts than with MII-phase cytoplasts (36 vs. 11%, P < 0.05). In contrast, when skin fibroblasts were used as donor cells, the use of an MII cytoplast (vs. G1/S phase) was imperative for blastocyst development (30 vs. 6%, P < 0.05). Differential staining showed that parthenogenetic, embryonic, and somatic cloned BL contained 26, 29, and 33% presumptive inner cell mass (ICM) cells, respectively, which is similar to that of frozen-thawed in vivo embryos at a comparable developmental stage (23%). These data indicate that embryonic and somatic nuclei require different recipient cytoplast environment for remodeling/ reprogramming, and this is likely due to the different cell cycle stage and profiles of molecular differentiation of the transferred donor nuclei.

Animals↗
PubMed2003

Precise recapitulation of methylation change in early cloned embryos.

Change of DNA methylation during preimplantation development is very dynamic, which brings this term to the most attractive experimental target for measuring the capability of cloned embryo to reprogram its somatic genome. However, one weak point is that the preimplantation stage carries little information on genomic sequences showing a site-specific re-methylation after global demethylation; these sequences, if any, may serve as an advanced subject to test how exactly the reprogramming/programming process is recapitulated in early cloned embryos. Here, we report a unique DNA methylation change occurring at bovine neuropeptide galanin gene sequence. The galanin gene sequence in early bovine embryos derived by in vitro fertilization (IVF) maintained a undermethylated status till the morula stage. By the blastocyst, certain CpG sites became methylated specifically, which may be an epigenetic sign for the galanin gene to start a differentiation programme. The same sequence was moderately methylated in somatic donor cell and, after transplanted into an enucleated oocyte by nuclear transfer (NT), came rapidly demethylated to a completion, and then, at the blastocyst stage, re-methylated at exactly the same CpG sites, as observed so in normal blastocysts. The precise recapitulation of normal methylation reprogramming and programming at the galanin gene sequence in bovine cloned embryos gives a cue for the potential of cloned embryo to superintend the epigenetic states of foreign genome, even after global demethylation.

Animals↗