Megakaryocytes and hepatocytes are unique cells in mammals that undergo polyploidization through endomitosis in terminal differentiation. Many polyploidization regulators and underlying mechanisms have been reported, most of which are tightly coupled with development, organogenesis, and cell differentiation. However, the nature of endomitosis, which involves successful entry into and exit from mitosis without complete cytokinesis, has not yet been fully elucidated. We highlight that endomitosis is a new cell fate in the cell cycle, and tetraploidy is a critical stage at the bifurcation of cell fate decision. This review summarizes the recent research progress in this area and provides novel insights into how cells manipulate mitosis toward endomitosis. Endomitotic cells can evade the tetraploidy restrictions and proceed to multiple rounds of the cell cycle. This knowledge not only deepens our understanding of endomitosis as a fundamental biological process but also offers new perspectives on the physiological and pathophysiological implications of polyploidization.
Hepatocytes/physiology* ; Megakaryocytes/physiology* ; Humans ; Polyploidy ; Animals ; Cell Cycle/physiology* ; Cell Differentiation ; Mitosis/physiology*

Polyploid cells, which contain more than one set of chromosome pairs, are very common in nature. Polyploidy can provide cells with several potential benefits over their diploid counterparts, including an increase in cell size, contributing to organ growth and tissue homeostasis, and improving cellular robustness via increased tolerance to genomic stress and apoptotic signals. Here, we focus on why polyploidy in the cell occurs and which stress responses and molecular signals trigger cells to become polyploid. Moreover, we discuss its crucial roles in cell growth and tissue regeneration in the heart, liver, and other tissues.
Humans ; Liver ; Hepatocytes ; Cell Cycle ; Polyploidy ; Homeostasis

Although somatic cells can be reprogrammed to pluripotent stem cells (PSCs) with pure chemicals, authentic pluripotency of chemically induced pluripotent stem cells (CiPSCs) has never been achieved through tetraploid complementation assay. Spontaneous reprogramming of spermatogonial stem cells (SSCs) was another non-transgenic way to obtain PSCs, but this process lacks mechanistic explanation. Here, we reconstructed the trajectory of mouse SSC reprogramming and developed a five-chemical combination, boosting the reprogramming efficiency by nearly 80- to 100-folds. More importantly, chemical induced germline-derived PSCs (5C-gPSCs), but not gPSCs and chemical induced pluripotent stem cells, had authentic pluripotency, as determined by tetraploid complementation. Mechanistically, SSCs traversed through an inverted pathway of in vivo germ cell development, exhibiting the expression signatures and DNA methylation dynamics from spermatogonia to primordial germ cells and further to epiblasts. Besides, SSC-specific imprinting control regions switched from biallelic methylated states to monoallelic methylated states by imprinting demethylation and then re-methylation on one of the two alleles in 5C-gPSCs, which was apparently distinct with the imprinting reprogramming in vivo as DNA methylation simultaneously occurred on both alleles. Our work sheds light on the unique regulatory network underpinning SSC reprogramming, providing insights to understand generic mechanisms for cell-fate decision and epigenetic-related disorders in regenerative medicine.
Male ; Mice ; Animals ; Cellular Reprogramming/genetics* ; Tetraploidy ; Pluripotent Stem Cells/metabolism* ; Induced Pluripotent Stem Cells/metabolism* ; DNA Methylation ; Spermatogonia/metabolism* ; Germ Cells/metabolism*

Self-organized blastoids from extended pluripotent stem (EPS) cells possess enormous potential for investigating postimplantation embryo development and related diseases. However, the limited ability of postimplantation development of EPS-blastoids hinders its further application. In this study, single-cell transcriptomic analysis indicated that the "trophectoderm (TE)-like structure" of EPS-blastoids was primarily composed of primitive endoderm (PrE)-related cells instead of TE-related cells. We further identified PrE-like cells in EPS cell culture that contribute to the blastoid formation with TE-like structure. Inhibition of PrE cell differentiation by inhibiting MEK signaling or knockout of Gata6 in EPS cells markedly suppressed EPS-blastoid formation. Furthermore, we demonstrated that blastocyst-like structures reconstituted by combining the EPS-derived bilineage embryo-like structure (BLES) with either tetraploid embryos or tetraploid TE cells could implant normally and develop into live fetuses. In summary, our study reveals that TE improvement is critical for constructing a functional embryo using stem cells in vitro.
Pregnancy ; Female ; Animals ; Mice ; Tetraploidy ; Blastocyst ; Embryo, Mammalian ; Cell Differentiation ; Embryonic Development

Objective: To explore the effect of dormant polyploid giant cancer cells (PGCC) on nasopharyngeal carcinoma (NPC) recurrence and to clarify the role of inhibition of autophagy in inhibiting NPC-PGCC formation and preventing NPC recurrence. Methods: NPC cells-derived PGCC (NPC-PGCC) were induced by paclitaxel (PTX), and the morphology, polyploid characteristics and cell activity of PGCC were identified by light microscopy, immunofluorescence and Live/Dead cell double staining assays. RNA-seq was used to analyze the differentially expressed genes between NPC-PGCC and diploid nasopharyngeal carcinoma cells CNE2. Functional enrichment and pathway annotation analysis of differentially expressed genes were performed using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG). The level of autophagy in NPC-PGCC cells was assessed by Western Blot and transmission electron microscopy analysis. The role of autophagy in the formation of NPC-PGCC and the effect of NPC-PGCC on the recurrence of nasopharyngeal carcinoma were studied using a highly clinically relevant mouse nasopharyngeal carcinoma recurrence model. Statistical analysis was performed using GraphPad Prism 6 and P-values<0.05 were considered statistically significant. Results: NPC-PGCC induced by paclitaxel had the characteristics of burst-like division after dormancy. GO enrichment and KEGG pathway analyses identified the significant biological processes and pathways mainly concentrated in autophagy and related pathways involving the differentially expressed genes between NPC-PGCC and diploid nasopharyngeal carcinoma cells CNE2. The autophagy level was significantly enhanced in NPC-PGCC cells. In a highly clinically relevant mouse nasopharyngeal carcinoma recurrence model, the number of PGCC in the primary tumor of the nude mice treated with cisplatin were higher than those of the other groups. In nude mice pretreated with autophagy inhibitor and then co-treatment with autophagy inhibitor and cisplatin, the number of PGCC in primary tumors was less and the recurrence rate was significantly lower than in other groups. Conclusions: The mechanism of dormant polyploid giant cancer cells formation is related to autophagy. Inhibition of autophagy can inhibit the formation of PGCC and thus prevent the recurrence of nasopharyngeal carcinoma.
Animals ; Autophagy ; Carcinoma/genetics* ; Cell Line, Tumor ; Cell Proliferation/genetics* ; Cisplatin/pharmacology* ; Gene Expression Regulation, Neoplastic ; Mice ; Mice, Nude ; Nasopharyngeal Carcinoma/genetics* ; Nasopharyngeal Neoplasms/pathology* ; Paclitaxel/pharmacology* ; Polyploidy

OBJECTIVE: To explore the genetic and clinical characteristics of near-tetraploidy/tetraploidy karyotype (NT/T) in patients with myelodysplastic syndrome (MDS). METHODS: Cytogenetic findings of 1576 inpatients with primary MDS were retrospective analyzed, among which 9 were diagnosed with NT/T. Clinical data including gender, age, morphology, genetic feature and prognosis were analyzed. RESULTS: The prevalence of MDS patients with NT/T (NT/T-MDS) among all cases was 0.57%. Karyotyping analysis suggested that eight MDS patients had sole NT/T, while the remainder one had a complex karyotype. In addition to the typical morphology of MDS, NT/T-MDS had unique morphology including huge blast, double-nuclear cell and irregular nuclear membrane. One NT/T-MDS patient gave up therapy, and the remaining eight underwent the first course of treatment, albeit with poor prognosis. Only one patient had complete remission, one had partial remission, three had no remission; and three had converted to acute myeloid leukemia. CONCLUSION NT/T-MDS is rare and has unique morphology. Generally, NT/T-MDS patients have poor prognosis. However, NT/T cannot be simply classified as high-risk group, but with consideration whether they have affected particular chromosomal structures as well as other clinical data.
Humans ; Karyotype ; Leukemia, Myeloid, Acute/complications* ; Myelodysplastic Syndromes/pathology* ; Prognosis ; Retrospective Studies ; Tetraploidy

Lycophytes and seed plants constitute the typical vascular plants. Lycophytes have been thought to have no paleo-polyploidization although the event is known to be critical for the fast expansion of seed plants. Here, genomic analyses including the homologous gene dot plot analysis detected multiple paleo-polyploidization events, with one occurring approximately 13-15 million years ago (MYA) and another about 125-142 MYA, during the evolution of the genome of Selaginella moellendorffii, a model lycophyte. In addition, comparative analysis of reconstructed ancestral genomes of lycophytes and angiosperms suggested that lycophytes were affected by more paleo-polyploidization events than seed plants. Results from the present genomic analyses indicate that paleo-polyploidization has contributed to the successful establishment of both lineages-lycophytes and seed plants-of vascular plants.
Evolution, Molecular ; Genome, Plant ; Genomics ; Phylogeny ; Polyploidy ; Selaginellaceae/genetics*

Parthenogenetic embryonic stem cells (pESCs) derived from bi-maternal genomes do not have competency of tetraploid complementation, due to lacking of paternal imprinting genes. To make pESCs possess fully development potentials and similar pluripotency to zygote-derived ESCs, we knocked out one allelic gene of the two essential maternal imprinting genes (H19 and IG) in their differentially methylated regions (DMR) via CRISPR/Cas9 system and obtained double knock out (DKO) pESCs. Maternal pESCs had similar morphology, expression levels of pluripotent makers and in vitro neural differentiation potentials to zygotes-derived ESCs. Besides that, DKO pESCs could contribute to full-term fetuses through tetraploid complementation, proving that they held fully development potentials. Derivation of DKO pESCs provided a type of major histocompatibility complex (MHC) matched pluripotent stem cells, which would benefit research in regenerative medicine.
Animals ; Embryonic Stem Cells ; Gene Knockout Techniques ; Genomic Imprinting ; Mice ; Parthenogenesis ; Pluripotent Stem Cells ; Regenerative Medicine ; Tetraploidy

PURPOSE: Platycodon grandiflorum (a domestic diploid variety, DV-PG) has been used as a food and component of various traditional oriental medicines. Although DV-PG is known to have an anti-allergic effect, little is known about the beneficial health effects of the tetraploid ‘Etteum’ variety in the Platycodon grandiflorum (TV-PG), which is a recently developed variety. In this study, we investigated the effect of TV-PG on the rat basophilic leukemia mast cell (RBL-2H3)-mediated allergic response. METHODS: To examine the effects of TV-PG on the allergic response, RBL-2H3 cells were sensitized with dinitropheny (DNP)-immunoglobin E, treated with various concentrations of TV-PG, and challenged with DNP-human serum albumin. We estimated cell granulation by measuring the release of β-hexosaminidase and production of inflammatory mediators by ELISA. RESULTS: TV-PG had no effect on the proliferation or cytotoxicity of RBL-2H3 cells within the concentration range of 0 to 200 µg/mL. TV-PG inhibited degranulation of RBL-2H3 cells by antigen stimulation in a dose-dependent manner. TV-PG also suppressed the production of inflammatory cytokines and mediators such as interleukin-4, tumor necrosis factor-α, prostagladin E2, and leukotriene B4 in RBL-2H3 cells by antigen stimulation. CONCLUSION: These results indicate that TV-PG exhibits anti-allergic activity via inhibition of degranulation as well as suppression of inflammatory mediators and cytokine release. These findings suggest that TV-PG may have potential as a preventive and therapeutic agent for the treatment of various allergic diseases.
Animals ; Basophils ; Cytokines ; Diploidy ; Enzyme-Linked Immunosorbent Assay ; Functional Food ; Hypersensitivity ; Inflammation Mediators ; Interleukin-4 ; Leukemia ; Leukotriene B4 ; Mast Cells ; Medicine, East Asian Traditional ; Necrosis ; Platycodon* ; Rats ; Serum Albumin ; Tetraploidy*

OBJECTIVETo diagnose chromosomal abnormalities in amniotic fluid cells by combining karyotyping and single nucleotide polymorphism array (SNP-array) analysis, and to explore the application of SNP-array in routine clinical practice.

METHODSConventional G banding was used to karyotype a fetal amniotic fluid sample and the corresponding peripheral blood samples from the parents, followed by SNP-array analysis of the fetal genomic DNA from the amniotic fluid.

RESULTSThe karyotype of the amniocytes was 47, XX, +mar. The marker chromosome was further identified as psu idic (22) (q11.2) by SNP-array analysis, revealing tetraploidy of a 1.7 Mb fragment in 22q11.1-q11.2 interval that involves the critical region for Cat eye syndrome.

CONCLUSIONA rare chromosomal abnormality was identified by combining conventional G banding and SNP-array. The high resolution SNP-array could provide more detailed information for determining the origin of chromosomal abnormalities.

Adult ; Amniotic Fluid ; cytology ; Aneuploidy ; Chromosome Disorders ; genetics ; Chromosomes, Human, Pair 22 ; genetics ; Eye Abnormalities ; genetics ; Female ; Humans ; Isochromosomes ; Karyotyping ; Polymorphism, Single Nucleotide ; Pregnancy ; Tetraploidy