Search Results (304)

Enhancer of zeste homologs inhibitory protein (EZHIP) is a eutherian-specific protein, with poorly defined developmental functions and physiological expression restricted to germ cells. Its aberrant re-expression characterizes posterior fossa ependymoma subtype A and a subset of diffuse midline gliomas with wild-type histone H3—aggressive pediatric brain tumors marked by global loss of the repressive H3 lysine 27 trimethylation (H3K27me3). Functionally analogous to the H3 lysine 27 to methionine (H3K27M) oncohistone, EZHIP inhibits Polycomb repressive complex 2 (PRC2), altering genome-wide H3K27me3 distribution and fate commitment. Unlike H3K27M, EZHIP is epigenetically silenced under physiological conditions yet inducible, suggesting context-dependent oncogenic roles. Its intrinsically disordered structure enables multifunctional interactions and biological versatility. Beyond brain tumors, EZHIP has emerged as an oncogenic driver in osteosarcoma, underscoring broader relevance across cancers. This review integrates current insights into EZHIP—from gene discovery and the mechanism of PRC2 inhibition to its emerging roles in metabolism, DNA repair, 3D chromatin regulation, and development. We outline EZHIP’s clinico-pathological significance in pediatric and adult malignancies, with an emphasis on EZHIP-driven hindbrain tumors. Finally, we discuss therapeutic opportunities, from the direct targeting of intrinsically disordered proteins to the indirect modulation of EZHIP-associated epigenetic and metabolic landscapes, highlighting implications for tumor evolution and precision oncology. Full article

Background: Functional constipation (FC) represents a highly prevalent gastrointestinal disorder, affecting approximately 8.5% of the population in China. It is frequently associated with anxiety and depression, significantly impairing patients’ quality of life. Conventional microecological therapeutic approaches predominantly rely on empirical probiotic–prebiotic combinations. However, these pairings are seldom selected based on strain-specific metabolic characteristics, ultimately leading to suboptimal therapeutic synergy. Methods: The generation time (GT) of four constipation-relief strains was measured across eight oligosaccharides to identify optimal substrates for synbiotic formulation. The GT-optimized synbiotic was verified in a loperamide-induced mouse model vs. single probiotics/prebiotics. The related mechanisms of were assessed through 16S rDNA sequencing, targeted metabolomics, and qPCR. Results: The GT-optimized synbiotic significantly outperformed all single components. Specifically, the synbiotic significantly decreased the time to first black stool and increased fecal water content. Mechanistically, it restored colonic neurotransmitter balance, suppressed aquaporin expression, enriched butyrate-producing bacteria, and repaired barrier integrity. Overall, these effects work together, increasing the moisture content of the feces and accelerating intestinal peristalsis, ultimately alleviating constipation. Conclusions: We propose a GT-guided precision-pairing strategy that identifies optimal prebiotics based on strain-specific generation times, demonstrating synergistic enhancement of short-chain fatty acid (SCFA) production, enteric neurotransmitter signaling, and aquaporin-mediated water transport. This GT guided synbiotic approach shows promise in preclinical models and warrants validation in human trials. Full article

Malformations of cortical development (MCD) are a group of neurodevelopmental disorders caused by abnormalities in cerebral cortex development, leading to conditions such as intellectual disability and refractory epilepsy. The prenatal phenotypes of MCD are complex and non-specific, complicating accurate diagnosis and prognosis assessment. Genetic testing, particularly chromosomal microarray analysis (CMA) and whole-exome sequencing (WES), has become an important tool for prenatal diagnosis. This review synthesizes current research on prenatal MCD, focusing on the integration of imaging and genetic diagnostic strategies based on the biological foundation of cortical development and the classification system of MCD. Prenatal MCD phenotypes show significant developmental stage clustering, with proliferation-phase abnormalities (62.9%) being the most common and microcephaly as the core phenotype. Genetic studies have revealed a high degree of genetic heterogeneity in MCD, with etiologies encompassing chromosomal abnormalities and a wide range of single-gene mutations. These mutations are clustered by phenotype: microcephaly is associated with neuronal proliferation/DNA repair genes; macrocephaly is driven by genes in the PI3K-AKT-mTOR and RAS-MAPK signaling pathways; and gyral and sulcal abnormalities are closely linked to microtubule-associated genes and migration pathways. De novo mutations account for the majority of pathogenic genetic alterations identified in MCD (50.6%); up to 75.1% of pathogenic mutations cannot be detected by routine prenatal screening. Based on this, the review emphasizes that for fetuses with suspected MCD, NGS, with WES at its core, plays an increasingly important role in achieving early and accurate prenatal diagnosis. Future research should prioritize the advancement of integrated diagnostic methods and large-scale cohort studies to further elucidate genotype–phenotype associations. Full article

Congenital Cataracts, Facial Dysmorphism, and Neuropathy (CCFDN) syndrome is a rare autosomal recessive disorder predominantly found among Vlax Roma populations, caused by a deep intronic founder variant in the CTDP1 gene. This review synthesizes recent advances in understanding the molecular mechanisms of CTDP1 dysfunction, highlighting its central role in transcriptional regulation, RNA splicing, DNA repair, and genome integrity. The unique splicing defect caused by the founder disease-causing variant in the Roma population results in a multisystem phenotype with early-onset neuropathy, congenital cataracts, and characteristic facial dysmorphism. Beyond its genetic homogeneity, CCFDN displays variable clinical severity and presents diagnostic challenges due to overlapping syndromic features. We discuss the emerging therapeutic landscape, focusing on antisense oligonucleotides, small molecule modulators, gene replacement, and genome or transcriptome editing strategies, while emphasizing the challenges in targeted delivery and efficacy. Ongoing insights into CTDP1’s broader biological functions and population genetics inform new directions for diagnosis, genetic counselling, and the development of effective therapies for this severe yet underrecognized disorder. Full article

GC-rich sequences affect DNA replication, recombination and repair, as well as RNA transcription in vivo. Such sequences may also impede site-directed mutagenesis in vitro. P3a site-directed mutagenesis is a highly efficient method, but it has not been tested with plasmids possessing GC-rich sequences. Here we report that it is very efficient with a BRPF3 expression vector but unsuccessful with that for KAT2B. Because two GC-rich regions located within the synthetic CAG promoter and the KAT2B coding region may form guanine (G)-quadruplexes and hinder plasmid denaturation during PCR, we developed P3b site-specific mutagenesis, achieving an average efficiency of 97.5% in engineering ten KAT2B mutants. Importantly, deletion mutagenesis revealed that either of the two GC-rich regions is sufficient for rendering the plasmid incompatible with P3a mutagenesis. Consistent with this, only P3b mutagenesis worked efficiently with several widely used sgRNA/Cas9 expression vectors, which contain the CAG promoter, and with an expression vector for CDK13, which possesses an intrinsically disordered domain encoded by a GC-rich DNA fragment. Thus, this study highlights serious challenges posed by GC-rich sequences to site-directed mutagenesis and provides an effective remedy to address such challenges. The findings support that G-quadruplex formation is one mechanism whereby such sequences impede regular PCR-based mutagenesis methods. Full article

The poly(ADP-ribose) polymerase (PARP) family constitutes a major group of proteins and enzymes essential for the maintenance of cellular homeostasis under physiological conditions and plays a pivotal role in the onset and progression of multiple pathological states. Members of the PARP family are classified into distinct subgroups based on their subcellular localization, structural organization, and ADP-ribosyltransferase activity. To date, the majority of studies have focused on DNA-dependent PARPs, owing to their well-established involvement in DNA repair mechanisms, cell cycle regulation, and diverse human pathologies. Nevertheless, over the past decade, a smaller subset of PARPs—limited in both abundance and enzymatic activity—has emerged as a critical regulator of numerous cellular processes, including embryonic development and disease progression. Within this subset, mono(ADP-ribosyl) transferases (MARTs) have gained growing attention as potential therapeutic targets in cancer, cardiovascular disorders, and neurodegenerative diseases. The ADP-ribose (ADPr) cycle, which comprises both branched poly(ADP-ribose) (PAR) polymers and mono-ADP-ribose moieties present either in free form or covalently bound to cellular substrates, is tightly regulated to ensure cellular homeostasis. This regulation relies on a finely tuned balance between ADP-ribosylation, DePARylation, and the subsequent recycling of mono-ADP-ribose. In this review, we provide a comprehensive overview of the biological roles of mono-ADP-ribosylation (MARylation) and DePARylation, with particular emphasis on their contribution to cancer-related processes. In addition, we discuss emerging evidence supporting their translational relevance and therapeutic potential. In conclusion, MARylation and DePARylation represent two increasingly recognized regulatory pathways whose expanding clinical significance highlights the need for deeper mechanistic understanding and further exploration in both basic and translational research. Full article

Xeroderma Pigmentosum group C (XP-C) is an autosomal recessive disorder caused by mutations in the XPC gene, leading to defective nucleotide excision repair. This defect leads to genomic instability and a profound cancer predisposition. To model this disease, we generated induced pluripotent stem cells (iPSCs) from an XP-C patient carrying a novel homozygous nonsense mutation in the XPC gene (c.1830C>A). The resulting iPSCs demonstrated typical pluripotent characteristics, including expression of key markers and trilineage differentiation capability. However, genomic assessment revealed progressive karyotypic instability during extended culture. While initial whole-genome sequencing detected no major chromosomal abnormalities, subsequent G-banding analysis identified acquired trisomy 12 in two lines (CL12 and CL27) and a derivative X chromosome in a third line (CL30). These abnormalities were absent in early-passage analyses, indicating that they were acquired and selected for during extended culture. The acquisition of a derivative X chromosome in CL30, alongside recurrent trisomy 12, represents a unique cytogenetic signature likely attributable to the underlying XPC defect. We hypothesize that the loss of GG-NER creates a permissive genomic environment, accelerating the accumulation of DNA damage and chromosomal missegregation under replicative stress. This temporal divergence in genomic integrity highlights how culture pressures drive chromosomal evolution in XP-C iPSCs independently of initial reprogramming. Our findings emphasize that XP-C iPSCs require continuous genomic surveillance and provide a model for investigating how DNA repair deficiencies interact with in vitro culture stress. Full article

The human sirtuins (SIRT1–SIRT7) are NAD⁺-dependent protein deacylases that orchestrate key cellular events such as metabolism, stress response, DNA repair, and aging. Accumulating evidence highlights their central role in women’s health. This review integrates recent insights into the roles of sirtuins across the female lifespan and their involvement in reproductive, metabolic, oncologic, and age-related disorders. Sirtuins regulate reproductive function, pregnancy outcomes, and hormone-dependent cancers. Their decline with aging contributes to menopausal and metabolic complications. Pharmacological interventions that enhance sirtuin activity, such as NAD⁺ precursors and SIRT1 activators, show promise in mitigating these conditions. Collectively, understanding the isoform- and tissue-specific roles of sirtuins provides a foundation for developing therapeutics to improve the lifespan and healthspan of women. Full article

Atherosclerosis, a major contributor to vascular damage and plaque formation, is brought on by cellular senescence and chronic inflammation. A crucial matter that emerges is the classification of the disease in order to understand the pathogenic mechanisms before treatment. Given that oxidative stress, DNA damage, and inflammation contribute to cellular senescence, an increase in pro-inflammatory factors is detected in the atherosclerotic plaque, which exacerbates its instability while impeding vascular repair. This study emphasizes the importance of pathways such as Nrf2, ICAM-1, and p38 MAPK/p16^INK4A in the development of atherosclerosis. It also underscores the potential of senescence-targeting interventions to complement the conventional treatments for atherosclerosis. The study promotes using senolytic approaches that may serve as effective adjuncts to conventional pharmacological treatments for atherosclerosis. Particularly, quercetin, a flavonoid, demonstrates a potential action as senolytic agent by mitigating macrophage senescence, improving lipid profiles, and reducing plaque size of up to 56% in experimental models. This review article advocates for integrating senolytic approaches, including nutraceuticals like quercetin and combination therapies, to improve cardiovascular health and age-related vascular disorders. Full article

Background/Objectives: Mosaic variegated aneuploidy (MVA) is a rare chromosomal instability disorder. Biallelic variants in SMC5, a core component of the DNA repair machinery, cause Atelis Syndrome, characterized by severe growth failure and multi-system abnormalities. This study aimed to identify the genetic cause in a patient with MVA and a distinct, milder phenotype. Methods: We conducted comprehensive clinical and cytogenetic assessments, chromosomal karyotyping, and trio-based exome sequencing on a proband with hypospadias and chromosomal instability. Identified variants were validated by Sanger sequencing and assessed for pathogenicity using ACMG/AMP guidelines. Results: Cytogenetic analysis revealed near-tetraploidy (9.7%) and MVA (46.9%). Exome sequencing identified novel compound heterozygous SMC5 variants, a nonsense c.2221G>T (p.Glu741Ter) and a missense c.3065A>G (p.Asn1022Ser), both predicted to disrupt SMC5/6 complex function. The proband presented with hypospadias and mild developmental delay but lacked the severe neurological, cardiac, or hematological manifestations typical of Atelis Syndrome. Karyotype analysis showed a distinct pattern of chromosomal abnormalities, including a high frequency of marker chromosomes. Conclusions: This report expands the genotypic and phenotypic spectrum of SMC5-related disorders, confirming its association with MVA/near-tetraploidy and describing a novel attenuated clinical presentation. The findings highlight distinct cytogenetic patterns potentially differentiating DNA repair-defective MVA from other subtypes. Full article

DNA is continuously exposed to endogenous and exogenous factors that induce oxidative modifications leading to mutations and genomic instability. Oxidative DNA damage plays a dual role, contributing to physiological signaling at low levels while promoting mutagenesis, carcinogenesis and degenerative diseases when unpaired. Among various lesions, an oxidized base, such as 8-oxo-2′-deoxyguanosine (8-oxodG), is one of the major biomarkers of oxidative stress and genomic damage. Cells have evolved sophisticated repair processes, including base excision repair (BER), nucleotide excision repair (NER), and mismatch repair (MMR), to maintain genomic integrity. Dysregulation or polymorphism of these repair genes has been linked with cancer, neurologic, and cardiovascular disorders. This review discusses an overview of what is presently known concerning oxidative DNA damage and repair mechanisms, particularly emphasizing their molecular players, signaling routes, and human disease implications. It further refers to the latest advances in CRISPR-based technologies and multi-omics approaches that are redefining our understanding of DNA damage response (DDR) networks and creating new frontiers for therapeutic interventions. Full article

Microcephaly with early-onset, intractable seizures, and developmental delay (MCSZ) is a rare inherited neurological disorder caused by biallelic loss-of-function variants in the polynucleotide kinase/phosphatase (PNKP) gene, which encodes an enzyme critical for DNA repair. Here, we describe the clinical history of two novel patients presenting with microcephaly, epilepsy, growth deficiency, language impairment, and severe intellectual disability. Brain MRI in both cases revealed complex cerebral malformations, including lissencephaly, ventriculomegaly, dysmorphic hippocampi, and cerebellar atrophy. Next-generation sequencing (NGS) analyses identified compound heterozygous PNKP variants in both patients. In case #1, we detected the missense variant p.Gln50Glu (c.148C>G) in exon 2 (rs756746191) and a novel nonsense variant, p.Gln248Ter (c.742C>T), leading to a premature stop codon in exon 7. In case #2, we identified the frameshift variant p.Thr424GlyfsTer49, caused by a 17-nucleotide duplication (c.1253_1269dupGGGTCGCCATCGACAAC) in exon 14 (rs587784365), along with a 15-nucleotide deletion (c.1386+49_1387-33delCCTCCTCCCCTGACCCC) in intron 15 (rs752902474). Over long-term follow-up (20 and 36 years for case #1 and case #2, respectively), seizures persisted in the first patient, while full control was achieved in the second case with combined therapy of valproate and clobazam. Along with a review of the literature, these two novel cases confirm the broad phenotypic spectrum of PNKP-associated disorders and underscore the importance of including PNKP in the genetic screening of patients presenting with developmental and epileptic encephalopathy (DEE) and microcephaly. Full article

Pediatric obesity is rising globally, and emerging evidence suggests that sleep timing may influence metabolic health through epigenetic mechanisms. This study investigated epigenome-wide DNA methylation patterns associated with bedtime in children and explored their biological relevance. Children aged 6–10 years were classified as early (≤8:30 PM) or late (>8:30 PM) bedtime groups. Saliva-derived DNA was analyzed using the Illumina Infinium MethylationEPIC BeadChip Array, and the Sparse Wrapper Algorithm (SWAG) was applied to identify differentially methylated loci. A total of 1006 CpG sites, representing 571 unique genes, were significantly associated with bedtime (p < 0.001). Significant methylation differences were observed between early and late bedtime groups, with ABCG2, ABHD4, MOBKL1A, AK3, SDE2, PRAMEF4, CREM, CDH4, BRAT1, and SDK1 showing the most consistent variation. Functional enrichment analyses (Gene Ontology, KEGG, and DisGeNET) conducted on the SWAG-identified gene set revealed enrichment in biological processes including peptidyl-lysin demethylation, regulation of sodium ion transport, DNA repair, and lipo-protein particle assembly. Key KEGG pathways included circadian entrainment, neurotransmission (GABAergic, dopaminergic, and glutamatergic), growth hormone synthesis, and insulin secretion. DisGeNET analysis identified associations with neurodevelopmental disorders and cognitive impairment. Cross-comparison with established sleep and obesity gene sets identified ten overlapping genes(CDH4, NR3C2, ACTG1, COG5, CAT, HDAC4, FTO, DOK7, OCLN, and ATXN1). These findings suggest that variations in bedtime during childhood may epigenetically modify genes regulating circadian rhythm, metabolism, neuronal connectivity, and stress response, potentially predisposing to later-life developmental, and metabolic challenges. Full article

Inherited retinal diseases (IRDs) are a clinically and genetically heterogeneous spectrum of disorders that lead to progressive and irreversible vision loss. Gene therapy is the most promising emerging treatment for IRDs. While gene augmentation strategies have demonstrated clinical benefit and results within the first approved ocular gene therapy, their application is restricted by adeno-associated virus (AAV) packaging capacity and limited efficacy for dominant mutations. Recent breakthroughs in precision genome editing, particularly base editing (BE) and prime editing (PE), have provided alternatives capable of directly correcting pathogenic variants. BE enables targeted single-nucleotide conversions, whereas PE further allows for precise insertions and deletions, both circumventing the double-strand DNA cleavage or repair processes typically induced by conventional CRISPR–Cas editing systems, thereby offering advantages in post-mitotic retinal cells. Preclinical investigations across murine and non-human primate models have demonstrated the feasibility, molecular accuracy, and preliminary safety profiles of these platforms in targeting IRD-associated mutations. However, critical challenges remain before clinical application can be realized, including limited editing efficiency in photoreceptors, interspecies variability in therapeutic response, potential risks of off-target effects, and barriers in large-scale vector manufacturing. Moreover, the delivery of genome editors to the outer retina remains suboptimal, prompting intensive efforts in capsid engineering and the development of non-viral delivery systems. This review synthesizes the current progress in BE and PE optimization, highlights innovations in delivery platforms that encompass viral and emerging non-viral systems and summarizes the major barriers to clinical translation. We further discuss AI-driven strategies for the rational design of BE/PE systems, thereby outlining their future potential and perspectives in the treatment of IRDs. Full article

Mitochondria are vital for cellular energy production, as these organelles generate most of the cellular energy required for various metabolic processes. Mitochondria contain their own circular DNA, which is present in multiple copies and is exclusively maternally inherited. Cellular energy in the form of adenosine 5′-triphosphate is produced via oxidative phosphorylation and involves the coordinated expression of genes encoded by both the nuclear and mitochondrial genomes. Mitochondrial DNA itself is replicated by a dedicated set of nuclear-encoded proteins composed of the DNA polymerase gamma, the Twinkle helicase, the mitochondrial single-stranded DNA binding protein, as well as several accessory factors. Mutations in these genes, as well as in the genes involved in nucleotide metabolism, are associated with a spectrum of mitochondrial disorders that can affect individuals from infancy to old age. Additionally, mitochondrial disease can arise as a result of point mutations, deletions, or depletion in the mitochondrial DNA or in genes involved in mitochondrial transcription, replication, maintenance, and repair. Although a cure for mitochondrial diseases is currently elusive, several treatment options have been explored. In this review, we explore the molecular insights of the core mitochondrial replisome proteins that have aided our understanding of mitochondrial diseases and influenced current therapies. Full article