Search Results (3,301)

Transposable elements (TEs), once regarded as genomic “junk,” are now recognized as powerful regulators of gene expression, genome stability, and innate immunity. In the context of neurodegeneration, particularly Amyotrophic Lateral Sclerosis (ALS), accumulating evidence implicates TEs as active contributors to disease pathogenesis. ALS is a fatal motor neuron disease with both sporadic and familial forms, linked to genetic, epigenetic, and environmental factors. While coding mutations explain a subset of cases, advances in long-read sequencing and epigenomic profiling have unveiled the profound influence of non-coding regions—especially retrotransposons such as LINE-1, Alu, and SVA—on ALS onset and progression. TEs may act through multiple mechanisms: generating somatic mutations, disrupting chromatin architecture, modulating transcriptional networks, and triggering sterile inflammation via innate immune pathways like cGAS-STING. Their activity is normally repressed by epigenetic regulators, including DNA methylation, histone modifications, and RNA interference pathways; however, these controls are compromised in ALS. Taken together, these insights underscore the translational potential of targeting transposable elements in ALS, both as a source of novel biomarkers for patient stratification and disease monitoring, and as therapeutic targets whose modulation may slow neurodegeneration and inflammation. This review synthesizes the current knowledge of TE biology in ALS; integrates findings across molecular, cellular, and systems levels; and explores the therapeutic potential of targeting TEs as modulators of neurodegeneration. Full article

This study investigated the metabolomic profiles and molecular basis of hybrid male sterility (HMS) in dzo (the male F1 hybrid offspring of taurine cattle (Bos taurus, ♂) × domestic yak (Bos grunniens, ♀)). In total, 147 co-different metabolites were identified between liver and testis tissues. Metabolomics analysis linked testis-specific abnormal citrate cycle and phenylalanine metabolism to dzo male infertility. Specifically, α-ketoglutaric acid, L-malic acid, and succinic acid were specific elevated in dzo testes, but not significantly different in liver. The testis-specific metabolite phenyllactate was reduced in dzo. Moreover, genes encoding α-ketoglutarate-dependent oxygenases were dysregulated only in dzo testes, including histone demethylations and RNA m⁶A modifications. Reactive oxygen species and m⁶A content were significantly decreased in dzo testes. Multiomics data showed that testis-specific metabolic abnormalities in dzo were linked to upregulated IDH3A and IDH3G, and downregulated testis-specific OGDHL and PDHA2. MiRNA-15b targeting to IDH3A was downregulated in dzo testes. The promoter of PDHA2 was hypermethylated and showed lower chromatin accessibility in dzo testes. Notably, testis-specific LDHC downregulation was also associated with lower phenyllactate in dzo testes, which could be an outcome of male infertility. Overall, this study provides comprehensive insights into the citrate cycle as a key pathway associated with dzo sterility, shedding light on the potential mitochondrial–nuclear incompatibility pertinent to addressing this HMS challenge. Full article

Pediatric thrombosis (PT) represents a rare condition that can manifest from neonatal life to adolescence, encompassing life-threatening complications. Its pathogenesis is attributed to immature hemostasis in conjunction with environmental and genetic factors, predominantly including those resulting in increased levels of plasminogen activator inhibitor 1 (PAI-1), the principal inhibitor of fibrinolysis, which is subject to upstream regulation by angiotensin-converting enzyme (ACE). Although the implication of microRNAs (miRNAs), epigenetic modulators of gene expression, has been demonstrated in adult thrombosis, evidence is lacking in the pediatric setting. Here, we investigated the involvement of two miRNA regulators of PAI-1 (SERPINE1 gene) in PT, in relation to clinical and genetic parameters that induce PAI-1 fluctuations. Following bioinformatic target-prediction, miRNA expression was assessed by quantitative real-time PCR in serum-samples of 19 pediatric patients with thrombosis (1–18 months post-incident), and 19 healthy controls. Patients were genotyped for the SERPINE1-4G/5G and ACE-I/D polymorphisms by PCR-based assays. Genotypic and thrombosis-related clinical data were analyzed in relation to miRNA-expression. Two miRNAs (miR-145-5p, miR-34a-5p) were identified to target SERPINE1 mRNA, with miR-34a additionally targeting the mRNA of ACE. The expression of miR-34a was significantly decreased in patients compared to controls (p = 0.029), while no difference was observed in miR-145 expression. Within patients, miR-34a expression demonstrated a peak 1–3 months post-thrombosis and was diminished upon treatment completion (p = 0.031), followed by a slight long-term increase. MiR-34a levels differed significantly by thrombosis site (p = 0.019), while a significant synergistic interaction between site and onset type (provoked/unprovoked) was detected (p = 0.016). Finally, an epistatic modification was observed in cerebral cases, since double homozygosity (4G/4G + D/D) led to a miR-34 decrease, with D/D carriership reversing the 4G/4G-induced upregulation of miR-34a (p = 0.006). Our findings suggest that in pediatric thrombosis, downregulation of miR-34a is indicative of impaired fibrinolytic capacity, attributed to deficient regulation of the inhibitory ACE/PAI-1 axis. Full article

Pharmacological chaperones of heterogeneous nuclear ribonucleoproteins (hnRNPs) show promise as potential neuroprotective drug candidates. They are expected to prevent the accumulation of neurotoxic hnRNP biocondensates and aggregates, which are hallmarks of severe degenerative diseases. Here, we present the first rational design of oligonucleotide chaperones of hnRNP A1. This design was inspired by previous studies on the specificity of the RNA recognition motif (RRM) and the RGG motif of hnRNP A1 for endogenous nucleic acids. To obtain robust and specific chaperones, we combined an RRM-binding sequence with an RGG-binding G-quadruplex oligonucleotide that inhibits hnRNP A1 aggregation and introduced various modifications into the sugar-phosphate backbone of the oligonucleotide. Modifications that locked the RRM-binding sequence in a conformational state characteristic of RNA improved chaperone affinity and activity. The former was assessed using microscale thermophoresis assays, while the latter was evaluated using fluorimetry and microscopy. The leading chaperone bound to hnRNP A1 at micromolar concentrations and inhibited the assembly of its condensates and amyloid-like aggregates (fibrils) by over 90%. Full article

RNA modifications comprise a core epigenetic dimension of gene regulation; among these, N6-methyladenosine (m6A) and 5-methylcytosine (m5C) have been most intensively investigated. While the functions of m6A in stem cell biology have been well characterized, the contributions of m5C remain comparatively less well defined. This review focuses on m5C modifications catalyzed by the NSUN family of RNA methyltransferases and their roles in regulating stem cell identity, pluripotency, and differentiation. Evidence from embryonic and mesenchymal stem cells, as well as animal models, demonstrates that NSUN-mediated m5C is deposited on diverse RNA substrates, including rRNA, tRNA, mRNA, mitochondrial RNA, and enhancer RNAs, thereby influencing processes such as self-renewal, cell cycle progression, RNA stability, metabolic activation, and lineage specification. Disruption of m5C regulation often leads to developmental defects, underscoring its essential role during embryogenesis. Collectively, these findings establish m5C as a versatile and dynamic regulator in stem cell biology and underscore the need for future studies to delineate the roles of the NSUN family in stem cells and define the RNA targets of m5C. In addition, its broader implications for development, regenerative medicine, and disease, including cancer, as well as its potential interplay with other RNA modifications such as m6A and pseudouridine, remain important areas for further investigation. Full article

N6-methyladenosine (m⁶A) is the most abundant and dynamic RNA modification in eukaryotic messenger and non-coding RNAs, playing a pivotal role in the post-transcriptional regulation of gene expression. The coordinated actions of m⁶A writers, erasers, and readers influence transcript stability, immune activation, and pathogen suppression. Growing evidence indicates that m⁶A fine-tunes the expression of defense-related genes, modulates RNA processing events, and is frequently hijacked by pathogens and pests to promote virulence. Notably, the dual role of m⁶A in enhancing plant defense and facilitating pathogen adaptation highlights its significance in the host–pathogen arms race. This review emphasizes recent advances in our understanding of m⁶A-mediated epitranscriptomic regulation in plants, with a focus on its role in responses to biotic stresses, including fungi, bacteria, virus infections, insects, and nematode attacks. This regulatory layer offers novel opportunities for crop protection through targeted manipulation of the epitranscriptomic mechanism. Full article

N6-methyladenosine (m⁶A) modifications are among the most prevalent epigenetic marks in eukaryotic RNAs, regulating both coding and non-coding RNAs and playing a pivotal role in RNA metabolism. Given their widespread influence, m⁶A modifications are deeply implicated in the pathogenesis of various cancers, including highly aggressive malignancies such as lung cancer, melanoma, and liver cancer. Dysregulation of m⁶A dynamics—marked by an imbalance in methylation and demethylation—can drive tumor progression, enhance metastatic potential, increase aggressiveness, and promote drug resistance, while also exerting context-dependent tumor-suppressive effects. Given this dual role, precise modulation of m⁶A levels and the activity of its regulatory enzymes (writers, erasers, and readers) represent a promising therapeutic avenue. In this review, we highlight recent advances in targeting m⁶A machinery, including small-molecule inhibitors, antisense oligonucleotides, and CRISPR/Cas-based editing tools, capable of both writing and erasing m⁶A marks and altering m⁶A methylation sites per se. By evaluating these strategies, we aim to identify the most effective approaches for restoring physiological m⁶A homeostasis or for strategically manipulating the m⁶A machinery for therapeutic benefit. Full article

Glioblastoma (GBM) is the most aggressive and lethal primary brain tumor, characterized by rapid proliferation, extensive vascularization, and resistance to conventional therapies. A feature of the GBM microenvironment is hypoxia, which activates a wide range of adaptive responses orchestrated mainly by the hypoxia-inducible factor (HIF). The Von Hippel–Lindau protein (pVHL) is a central regulator of HIF stability, inducing proteasomal degradation under physiological conditions. However, in GBM, the pVHL is frequently mutated or functionally inactivated by several mechanisms, including microRNA regulation, post-translational modifications, or degradation by specific E3 ubiquitin ligases. This loss of function results in persistent HIF activation, thereby enhancing the oncogenic and pro-angiogenic environment that contributes to the progression and aggressiveness of GBM. This review focuses on the multifaceted roles of the pVHL-HIF axis and proposes it as a key driver of GBM malignancy. Full article

Alterations in both oral and gut microbiomes have been associated with Alzheimer’s disease and related dementia (ADRD). While extensive research has focused on the role of gut dysbiosis in ADRD, the contribution of the oral microbiome remains relatively understudied. This study aims to evaluate distinct patterns and potential synergistic effects of oral and gut microbiomes in a cohort of predominantly Hispanic individuals with cognitive impairment (CI) and without cognitive impairment (NC). We conducted 16S rRNA gene sequencing on stool and saliva samples from 32 participants (17 CI, 15 NC; 62.5% female, mean age = 70.4 ± 6.2 years) recruited in San Antonio, Texas, USA. Differential abundance analysis evaluated taxa with significant differences between both groups. While diversity metrics showed no significant differences between CI and NC groups, differential abundance analysis revealed an increased presence of oral genera such as Dialister, Fretibacterium, and Mycoplasma in CI participants. Conversely, CI individuals exhibited a decreased abundance of gut genera, including Shuttleworthia, Holdemania, and Subdoligranulum, which are known for their anti-inflammatory properties. No evidence was found for synergistic contributions between oral and gut microbiomes in the context of CI. Our findings suggest that like the gut microbiome, the oral microbiome of CI participants undergoes significant modifications. Notably, the identified oral microbes have been previously associated with periodontal diseases and gingivitis. These results underscore the necessity for further investigations with larger sample sizes to validate our findings and elucidate the complex interplay between oral and gut microbiomes in ADRD pathogenesis. Full article

Specific expression of genes is fundamental for defining the identity and the functional state of cells. Sequence-specific transcription factors interpret the information contained in DNA sequence motifs and recruit cofactors to modify chromatin and control RNA polymerases. This multi-step process typically involves several transcription factors and cofactors with different enzymatic activities. Post-translational modifications (PTMs) of histones are one key mechanism to control chromatin structure and polymerase activity and thus gene transcription. The methylation of histone H3 at lysine 4 (H3K4) is a modification of accessible chromatin, including enhancers and promoters, and also sites of recombination and some forms of DNA damage. H3K4 methylation is catalyzed by six lysine methyltransferase complexes, referred to as KMT2 or COMPASS-like complexes. These are important in processes related to transcription and contribute to recombination in T and B cells. PRDM9 and ASH1L are H3K4 methyltransferases involved in meiotic recombination and DNA repair, respectively. In transcription, H3K4 mono- and tri-methylation are located at enhancers and promoters, respectively. These modifications, either alone or in combination with other histone PTMs, provide binding sites for transcriptional cofactors. Through these sites, H3K4 methylation affects chromatin accessibility and histone PTMs, typically resulting in a favorable environment for transcription. H3K4 tri-methylation also recruits and regulates RNA polymerase II (RNAPII) complexes, which interact with KMT2 complexes, generating positive feedforward loops to promote transcription. Thus, H3K4 methylation has broad activities that are key to different chromatin-associated processes. Full article

A reassessment of the risk-benefit balance of the two lipid nanoparticle (LNP)-based vaccines, Pfizer’s Comirnaty and Moderna’s Spikevax, is currently underway. While the FDA has approved updated products, their administration is recommended only for individuals aged 65 years or older and for those aged 6 months or older who have at least one underlying medical condition associated with an increased risk of severe COVID-19. Among other factors, this change in guidelines reflect an expanded spectrum and increased incidence of adverse events (AEs) and complications relative to other vaccines. Although severe AEs are relatively rare (occurring in <0.5%) in vaccinated individuals, the sheer scale of global vaccination has resulted in millions of vaccine injuries, rendering post-vaccination syndrome (PVS) both clinically significant and scientifically intriguing. Nevertheless, the cellular and molecular mechanisms of these AEs are poorly understood. To better understand the phenomenon and to identify research needs, this review aims to highlight some theoretically plausible connections between the manifestations of PVS and some unique structural properties of mRNA-LNPs. The latter include (i) ribosomal synthesis of the antigenic spike protein (SP) without natural control over mRNA translation, diversifying antigen processing and presentation; (ii) stabilization of the mRNA by multiple chemical modification, abnormally increasing translation efficiency and frameshift mutation risk; (iii) encoding for SP, a protein with multiple toxic effects; (iv) promotion of innate immune activation and mRNA transfection in off-target tissues by the LNP, leading to systemic inflammation with autoimmune phenomena; (v) short post-reconstitution stability of vaccine nanoparticles contributing to whole-body distribution and mRNA transfection; (vi) immune reactivity and immunogenicity of PEG on the LNP surface increasing the risk of complement activation with LNP disintegration and anaphylaxis; (vii) GC enrichment and double proline modifications stabilize SP mRNA and prefusion SP, respectively; and (viii) contaminations with plasmid DNA and other organic and inorganic elements entailing toxicity with cancer risk. The collateral immune anomalies considered are innate immune activation, T-cell- and antibody-mediated cytotoxicities, dissemination of pseudo virus-like hybrid exosomes, somatic hypermutation, insertion mutagenesis, frameshift mutation, and reverse transcription. Lessons from mRNA-LNP vaccine-associated AEs may guide strategies for the prediction, prevention, and treatment of AEs, while informing the design of safer next-generation mRNA vaccines and therapeutics. Full article

Background: Regular endurance training induces physiological changes in cardiac structure and function. The precise epigenetic mechanisms by which cardiovascular adaptations are mediated are still unclear. This review seeks to clarify the role of epigenetic regulation in exercise-induced cardiovascular adaptation. Methods: This systematic review was conducted in accordance with the PRISMA guidelines up to 30 April 2025, using the databases PubMed, VHL, and LILACS Plus. Studies were included if they focused on microRNA expression and DNA methylation in individuals with cardiovascular disease who underwent endurance training. Results: Six articles, including 384 participants with heart failure, coronary artery disease, and hypertension, were included in the final analysis. Changes in DNA methylation and microRNA expression of specific genes involved in cardiovascular structural and functional adaptation were observed. Significant improvements were found in body composition, VO_2peak, systolic and diastolic blood pressure, and left ventricular function and structure. Conclusions: Endurance training has a positive impact on epigenetic mechanisms related to cardiovascular structural and functional adaptation. A clear causal link between epigenetic modifications and clinical outcomes remains to be established. Full article

Starvation in horses presents critical welfare, economic, and management challenges with underlying molecular mechanisms of metabolic modification and recovery left poorly defined. Prolonged caloric deprivation induces significant systemic shifts in carbohydrate, protein, and lipid metabolism, reflected in coordinated changes in tissue-specific gene expression. This review synthesizes current knowledge on equine metabolic responses to starvation, emphasizing pathways found through RNA sequencing (RNA-seq) and real-time quantitative polymerase chain reaction (RT-qPCR) studies. Molecular investigations using RNA-seq and RT-qPCR have provided insight into transcriptional reprogramming during starvation and subsequent refeeding. Shifts in gene expression reflect the metabolic transition from carbohydrate dependence to lipid use, suppression of anabolic signaling, and activation of proteolytic pathways. However, interpretation of these data requires caution, as factors such as post-mortem interval, tissue handling, and euthanasia methods particularly the use of sodium barbiturates can influence transcript stability and abundance, potentially confounding results. The literature shows that starvation-induced molecular changes are not uniform across tissues, with skeletal muscle, liver, and adipose tissue showing distinct transcriptional signatures and variable recovery patterns during refeeding. Cross-species comparisons with hibernation, caloric restriction, and cachexia models provide context for understanding these changes, though equine-specific studies remain limited. Identified gaps include the scarcity of longitudinal data, inconsistent tissue sampling protocols, and lack of standardized reference genes for transcriptomic analyses in horses. Addressing these limitations will improve the accuracy of molecular evaluations and enhance our ability to predict recovery trajectories. A more comprehensive understanding of systemic and tissue-specific responses to starvation will inform evidence-based rehabilitation strategies, reduce the risk of refeeding syndrome, and improve survival and welfare outcomes for affected horses. Full article

The submandibular glands (SMGs), along with the parotid and sublingual glands, generate the majority of saliva and play critical roles in maintaining oral and systemic health. Despite their physiological importance, long-term therapeutic options for salivary gland dysfunction remain limited, highlighting the need for a deeper molecular understanding of SMG biology, particularly in humans. To address this knowledge gap, we have performed transcriptomic- and epigenomic-based analyses and molecular characterization of the human SMG. Our integrated analysis of multiorgan RNA-sequencing datasets has identified an SMG-enriched gene expression signature comprising 289 protein-coding and 75 long non-coding RNA (lncRNA) genes that include both known regulators of salivary gland function and several novel candidates ripe for future exploration. To complement these transcriptomic studies, we have generated chromatin immunoprecipitation sequencing (ChIP-seq) datasets of key histone modifications on human SMGs. Our epigenomic analyses have allowed us to identify genome-wide enhancers and super-enhancers that are likely to drive genes and regulatory pathways that are important in human SMG biology. Finally, comparative analysis with mouse and human SMG and other tissue datasets reveals evolutionary conserved gene and regulatory networks, underscoring fundamental mechanisms of salivary gland biology. Collectively, this study offers a valuable knowledge-based resource that can facilitate targeted research on salivary gland dysfunction in human patients. Full article

RNA-based therapeutics offer transformative potential for treating devastating diseases. However, current RNA delivery technologies face significant hurdles, including inefficient tissue targeting, insufficient selectivity, and severe side effects, leading to the termination of many clinical trials. This review critically assesses the landscape of RNA-derived medicines, examining world-renowned mRNA vaccines (Spikevax, BNT162b2/Comirnaty) and RNA-based therapeutics like Miravirsen (anti-miR-122). It details the composition and clinical trial results of numerous modified short RNA drugs (e.g., siRNAs, miRNA mimetics/inhibitors) targeting various conditions. Prospects for RNA-based medicines are analysed for diseases with substantial societal impact, such as cancer, autoimmune disorders, and infectious diseases, with a focus on evolving delivery methods, including lipid nanoparticles, viral vectors, and exosomes. RNA-mediated macrophage reprogramming emerges as a promising strategy, potentially enhancing both delivery and clinical efficacy. This review highlights that while approved RNA therapies primarily target rare diseases due to delivery limitations, novel approaches in RNA modification, targeted delivery systems, and enhanced understanding of molecular mechanisms are crucial for expanding their application to prevalent diseases and unlocking their full therapeutic potential. Full article