Parental imprinting is an epigenetic process leading to monoallelic expression of certain genes depending on their parental origin. Imprinting diseases are characterized by growth and metabolic issues starting from birth to adulthood. They are mainly due to methylation defects in imprinting control region that drive the abnormal expression of imprinted genes. We currently lack relevant animal or cellular models to unravel the pathophysiology of growth failure in these diseases. We aimed to characterize the methylation of imprinting regions in dental pulp stem cells and during their differentiation in osteogenic cells (involved in growth regulation) to assess the interest of this cells in modeling imprinting diseases. We collected dental pulp stem cells from five controls and four patients (three with Silver-Russell syndrome and one with Beckwith-Wiedemann syndrome). Methylation analysis of imprinting control regions involved in these syndromes showed a normal profile in controls and the imprinting defect in patients. These results were maintained in dental pulp stem cells cultured under osteogenic conditions. Furthermore, we confirmed the same pattern in six other loci involved in imprinting diseases in humans. We also confirmed monoallelic expression of H19 (an imprinted gene) in controls and its biallelic expression in one patient. Extensive imprinting control regions methylation analysis shows the strong potential of dental pulp stem cells in modeling imprinting diseases, in which imprinting regions are preserved in culture and during osteogenic differentiation. This will allow to perform in vitro functional and therapeutic tests in cells derived from dental pulp stem cells and generate other cell-types.
Adult ; Animals ; DNA Methylation ; Dental Pulp ; Genomic Imprinting ; Humans ; Osteogenesis/genetics* ; Stem Cells

The overall prevalence of uniparental disomy (UPD) across all chromosomes was estimated to be around one birth in 2000. To date, more than 4170 UPD cases have been registered. UPD for chromosomes 6, 7, 11, 14, 15, and 20 can result in clinically recognizable imprinting disorders due to abnormal levels of imprinted gene expression. For other chromosomes, the clinical consequences associated with UPD are not apparent, unless when a recessive genetic disorder is unmasked by UPD or regions of homozygosity (ROH). A clinical practice guideline will assist in strengthening the precise analysis and interpretation of the clinical significance of ROH/UPD. This guideline summarizes the conception, mechanism and clinical consequences of ROH/UPD, as well as the principles for data analysis, with an aim to standardize the clinical application and data interpretation.
Gene Expression ; Genomic Imprinting ; Homozygote ; Humans ; Uniparental Disomy/genetics*

Uniparental disomy (UPD) refers to a chromosome defect that an individual's homologous chromosome or segments are inherited from one parent. UPD can cause either aberrant patterns of genomic imprinting or homozygosity of mutations, leading to various diseases, including cancer. The mechanisms of UPD formation are diverse but largely due to the incorrect chromosome separation during cell division. UPD does not alter the number of gene copies, thus is difficult to be detected by conventional cytogenetic techniques effectively. Assisted by the new techniques such as single nucleotide polymorphism arrays, more and more UPD-related cases have been reported recently. UPD events are non-randomly distributed across cancer types, which play important role in the occurrence, development and metastasis of cancer. Here we review the research progress on the formation mechanisms, detection methods, the involved chromosomal regions and genes, and clinical significance of UPD; and also discuss the directions for future studies in this field.
Genomic Imprinting ; Humans ; Neoplasms ; genetics ; Research ; trends ; Uniparental Disomy

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

BACKGROUND AND OBJECTIVES: Genomic imprinting modulates growth and development in mammals and is associated with genetic disorders. Although uniparental embryonic stem cells have been used to study genomic imprinting, there is an ethical issue associated with the destruction of human embryos. In this study, to investigate the genomic imprinting status in human neurodevelopment, we used human uniparental induced pluripotent stem cells (iPSCs) that possessed only maternal alleles and differentiated into neural cell lineages. METHODS: Human somatic iPSCs (hSiPSCs) and human parthenogenetic iPSCs (hPgiPSCs) were differentiated into neural stem cells (NSCs) and named hSi-NSCs and hPgi-NSCs respectively. DNA methylation and gene expression of imprinted genes related neurodevelopment was analyzed during reprogramming and neural lineage differentiation. RESULTS: The DNA methylation and expression of imprinted genes were altered or maintained after differentiation into NSCs. The imprinting status in NSCs were maintained after terminal differentiation into neurons and astrocytes. In contrast, gene expression was differentially presented in a cell type-specific manner. CONCLUSIONS: This study suggests that genomic imprinting should be determined in each neural cell type because the genomic imprinting status can differ in a cell type-specific manner. In addition, the in vitro model established in this study would be useful for verifying the epigenetic alteration of imprinted genes which can be differentially changed during neurodevelopment in human and for screening novel imprinted genes related to neurodevelopment. Moreover, the confirmed genomic imprinting status could be used to find out an abnormal genomic imprinting status of imprinted genes related with neurogenetic disorders according to uniparental genotypes.
Alleles ; Astrocytes ; Cell Lineage ; DNA Methylation ; Embryonic Stem Cells ; Embryonic Structures ; Epigenomics ; Ethics ; Gene Expression ; Genomic Imprinting ; Genotype ; Growth and Development ; Humans ; In Vitro Techniques ; Induced Pluripotent Stem Cells ; Mammals ; Mass Screening ; Neural Stem Cells ; Neurons

Like the body of Hominin, mind is the result of natural selection. Therefore, an evolutionary approach in the biological aspects is essential for an intrinsic understanding of mental disorders. However, the evolutionary medical approach to mental disordershas not been well researched because evolutionary psychiatry is not widely accepted, and the conceptual paradigm has not been unified. Nevertheless, some evolutionary hypotheses about some mental disorders have been proposed, including the following: 1) thesimple disease argument that mental disorder is a mere disease, 2) the genomic lag hypothesis that current genes are incompatible with evolutionary environmental changes, 3) the developmental mismatch hypothesis that brain development cannot reflect entire-information of surrounding environment, 4) the trade-off hypothesis that costs are offset by other adaptive benefits, 5) the by-product hypothesis that mental disorders are inevitable outcome of evolutionary design, 6) the cliff-edge model that the encephalizationin the Hominin caused mental disorders, 7) the inclusive fitness hypothesis that costs of individual are compensated by benefits of kinship, 8) the antagonistic polymorphism hypothesis that differential costs and benefits according to sex or age cause ofpolymorphic psychological traits 9) the heterozygote advantage hypothesis that the heterozygous genotypes have higher relative fitness, so they can persist even though homozygous genotypes cause mental disorders, and 10) a genomic imprinting hypothesis that conflicts between maternal genes and paternal genes cause mental disorders. I will summarize and compare the evolutionary hypotheses of mental disorders and present the lim itations of each hypothesis.
Brain ; Cost-Benefit Analysis ; Genomic Imprinting ; Genotype ; Heterozygote ; Hominidae ; Humans ; Mental Disorders ; Selection, Genetic

OBJECTIVETo explore the genetic cause for two children with omphalocele.

METHODSThe patients were examined, and the medical history of their families was collected. Methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) was performed to detect potential mutation in the patients.

RESULTSLoss of methylation of imprinting center 2 (IC2) at the 11p15.5 region of the maternal chromosome was detected in both children.

CONCLUSIONThe two patients were diagnosed with Beckwith-Wiedemann syndrome by MS-MLPA. The loss of methylation of IC2 probably underlies the disease in both patients.

Beckwith-Wiedemann Syndrome ; genetics ; Chromosomes, Human, Pair 11 ; DNA Methylation ; Female ; Genomic Imprinting ; Humans ; Infant ; Infant, Newborn ; Male ; Multiplex Polymerase Chain Reaction

Objective: To investigate the influence of high fat diet-induced obesity (HFDIO) on the differentially methylated region (DMR) of the imprinted gene and global genome methylation of sperm DNA. METHODS: We performed bisulfite sequencing on the DMR of the imprinted gene and global genome methylation of sperm DNA in the mouse model of HFDIO. RESULTS: No statistically significant differences were found between the HFDIO model and normal control mice in MEG3-IG (93.73 vs 97.26%, P = 0.252), H19 (98.00 vs 97.83%, P = 0.920), IGF2 (97.34 vs 96.25%, P =0.166), IGF2R (1.43 vs 1.11%, P = 0.695), PEG3 (0.19 vs 0.38%, P = 0.537), MEST (0.23 vs 0.68%, P = 0.315), NNAT (0.31 vs 0.00%, P = 0.134), or SNRPN (1.88 vs 3.13%, P = 0.628). A total of 8 942 DMRs were detected across the sperm genome (P <0.05). Gene functional enrichment analysis indicated that the enriched terms with the largest numbers of genes were the metabolic process (n = 1 482), RNA synthesis (n = 779), and transcription (n = 767). CONCLUSIONS The methylation level underwent no significant change in the DMRs of the imprinted genes from the mice with HFDIO, but the CG methylation of the genes involved in the metabolic process, RNA synthesis and transcription were significantly altered.
Animals ; DNA Methylation ; Diet, High-Fat ; Genome ; Genomic Imprinting ; Insulin-Like Growth Factor II ; Male ; Mice ; Obesity ; genetics ; metabolism ; RNA ; biosynthesis ; Spermatozoa ; metabolism

The connection between male infertility and abnormal methylation of imprinted genes has attracted much attention. Some imprinted genes, e.g., H19, MEG3, MEST and SNRPN, are known to be related with male infertility. Abnormal imprinted information may influence sperm concentration, motility and morphology, but the mechanism is still unclear. Sperm genomic imprinting reconstruction and erase respectively occur at the time of spermatogenesis and before embryo transfer. Many studies have shown that the probability of imprinting disorder syndrome of offspring born through assisted reproductive technology (ART) was significantly higher, leading to the worry about the safety of ART and speculation that the operation and in vitro environment may affect sperm imprinted information, which in turn may lead to imprinting diseases in the offspring. However, above connection still lacks convincing evidence. This paper has conducted a literature review of recent literature and explored the impact of abnormal methylation of imprinted genes on male fertility and the offspring.
Genomic Imprinting ; Humans ; Infertility, Male ; genetics ; Male ; Proteins ; genetics ; RNA, Long Noncoding ; genetics ; Reproductive Techniques, Assisted

A subset of mammalian genes differ functionally between two alleles due to genomic imprinting, and seven such genes (Peg3, Usp29, APeg3, Zfp264, Zim1, Zim2, Zim3) are localized within the 500-kb genomic interval of the human and mouse genomes, constituting the Peg3 imprinted domain. This Peg3 domain shares several features with the other imprinted domains, including an evolutionarily conserved domain structure, along with transcriptional co-regulation through shared cis regulatory elements, as well as functional roles in controlling fetal growth rates and maternal-caring behaviors. The Peg3 domain also displays some unique features, including YY1-mediated regulation of transcription and imprinting; conversion and adaptation of several protein-coding members as ncRNA genes during evolution; and its close connection to human cancers through the potential tumor suppressor functions of Peg3 and Usp29. In this review, we summarize and discuss these features of the Peg3 domain.
Alleles ; Animals ; Fetal Development ; Genes, Tumor Suppressor ; Genome ; Genomic Imprinting ; Humans ; Mice ; YY1 Transcription Factor