Search Results (169)

Human methyltransferase-like protein 16 (METTL16) installs N⁶-methyladenosine on U6 small nuclear RNA (snRNA) and other RNAs. Multiple X-ray crystal structures of METTL16 have been published; however, we do not yet fully understand the structure–function relationships of specific residues. We designed 38 mutants, including seven cancer-associated mutants, and used electrophoretic mobility shift assays and single-turnover kinetic assays to better understand the functional roles of specific domains and amino acid residues in binding to U6 snRNA, formation of the METTL16•U6 snRNA•S-adenosylmethionine (SAM) complex, and the rate of methylation. While point mutations in the methyltransferase domain mildly weaken the binding of METTL16 to U6 snRNA, the C-terminal vertebrate conserved regions (VCRs), particularly the arginine-rich region (R382 to R388), mediate cooperative binding and contribute more to RNA binding. All METTL16 K-loop mutants displayed tighter SAM binding, suggesting that the K-loop blocks SAM binding. In addition, residues E133 and F227 are critical for stabilizing SAM binding. Mutations in the ₁₈₄NPPF₁₈₇ catalytic core and R282A abolished methyltransferase activity. Two METTL16 somatic cancer-associated mutants (G110C and R241Dfs*2) displayed reduced methylation activity. This mutational analysis expands our understanding of how specific domains and residues contribute to substrate-binding activity and methylation of U6 snRNA catalyzed by METTL16. Full article

Asthma is a chronic inflammatory airway disease influenced by both genetic and environmental factors. Recent insights have underscored the pivotal role of epigenetic regulation in the pathogenesis and heterogeneity of asthma. This review focuses on key epigenetically important regulators categorized as writers, erasers, and readers that govern DNA methylation, histone modifications, and RNA modifications. These proteins modulate gene expression without altering the underlying DNA sequence, thereby influencing immune responses, airway remodeling, and disease severity. We highlight the structural and functional dynamics of histone acetyltransferases (e.g., p300/CBP), histone deacetylases (e.g., SIRT family), DNA methyltransferases (DNMT1, DNMT3A), demethylases (TET1), and methyl-CpG-binding proteins (MBD2) in shaping chromatin accessibility and transcriptional activity. Additionally, the m6A RNA modification machinery including METTL3, METTL14, FTO, YTHDF1/2, IGF2BP2, and WTAP is explored for its emerging significance in regulating post-transcriptional gene expression during asthma progression. Structural characterizations of these proteins reveal conserved catalytic domains and interaction motifs, mirroring their respective families such as SIRTs, p300/CBP, DNMT1/3A, and YTHDF1/2 critical to their epigenetic functions, offering mechanistic insight into their roles in airway inflammation and immune modulation. By elucidating these pathways, this review provides a framework for the development of epigenetic biomarkers and targeted therapies. Future directions emphasize phenotype-specific epigenomic profiling and structure-guided drug design to enable precision medicine approaches in asthma management. Full article

Background: The function and mechanism of N6-methyladenosine (m6A) methylation in pressure-overload cardiac fibrosis remains limited and unclear. This study aims to analyze and predict m6A modifications present in mouse hearts because of transverse aortic constriction (TAC). Materials and Methods: Twelve male C57BL/6 mice were randomly assigned to two groups, TAC group and sham group. The RNA Dot Blot assay was employed to evaluate the overall m6A methylation levels in both TAC and sham mice. The expression level of m6A-related enzymes were investigated through RT-PCR and Western blotting. MeRIP-seq and RNA-seq analyses were conducted to identify differentially modified m6A genes and mRNA expression genes. The protein–protein interaction (PPI) network was carried out to choose potential hub genes. Additionally, the transcription factor (TF)–microRNA (miRNA) coregulatory network and the drug–hub gene interaction network were built based on these hub genes. Furthermore, molecular docking simulations were also performed to analyze the interactions between drugs and hub genes. Results: Compared with the sham group, the TAC group demonstrated elevated levels of global m6A methylation. METTL3 and METTL14 were significantly upregulated, whereas FTO and ALKBH5 were significantly downregulated following TAC. MeRIP-seq analysis identified 17,806 m6A peaks associated with 9184 genes and 16,392 m6A peaks associated with 8550 genes in the TAC and sham groups, respectively. In conjunction with RNA-seq data, 66 genes were identified as exhibiting concurrent differences in both m6A methylation levels and mRNA expression. Six hub genes, Cd33, Irf4, Nr4a2, Hspa1b, Nr4a1, and Adcy1, were identified through the construction of a PPI network. The TF-miRNA coregulatory network contains six hub genes, 31 miRNAs, and 24 TFs. The drug–hub genes interaction network included five hub genes and 36 candidate drugs. Conclusions: The m6A modification is prevalent in TAC-induced cardiac fibrosis and significantly contributes to the fibrotic process by regulating critical genes. In the future, it may emerge as one of the potential cardiac fibrosis therapeutic targets. Full article

The dysregulation of m6A-related genes recognized as ‘writers’, ‘readers’, and ‘erasers’ is reported to be involved in the initiation, progression, and drug resistance of acute myeloid leukemia (AML). In the present study, we investigated the expression levels of various readers, writers, and erasers in pediatric AML patients. Additionally, we categorized the patients according to the molecular subtyping of common mutations and recurrent fusions and correlated the expression of m6A-associated genes with different molecular subtypes and evaluated their prognostic and clinical implications. A total of fifty-seven patients with pediatric de novo AML were enrolled in the study. The study cohort consisted of 41 males and 16 females with a median age of 7 years (range 1 to 12 years). A high expression of m6A RNA modification complex genes was noted in AML patients. Among the writers, METTL3 and METTL14 were found to be upregulated in 19 and 17 patients, the readers YTHDF1 and YTHDF2 showed higher expression in 6 and 10 patients, while a high expression of erasers FTO and ALKBH5 was found in 28 patients and 1 patient, respectively. Further, the expression of m6A regulators showed a significant association with genetic alterations including FLT3-ITD, RBM15::MKL fusions and NPM1 mutations. Additionally, while evaluating the prognostic implications, both the readers YTHDF1 and YTHDF2 showed a significant correlation with TLC at diagnosis (p < 0.05). Further, Kaplan–Meier estimation showed a poor event-free survival in cases with the overexpression of YTHDF1 (log-rank p = 0.028). Additionally, we noted a strong correlation between YTHDF1 overexpression and treatment-related mortality (log-rank p < 0.001), and a nearly significant correlation with YTHDF2 expression in such patients (log-rank p = 0.053) at a median follow-up of 8 months. Thus, our data suggest that m6A genes, especially readers YTHDF1 and YTHDF2, are involved in the disease prognosis of AML and probably function in an integrated manner with other m6A-modifying genes to subsequently play a role in AML pathogenesis. Full article

Neurodegeneration is increasingly recognized not as a linear trajectory of protein accumulation, but as a multidimensional collapse of biological organization—spanning intracellular signaling, transcriptional identity, proteostatic integrity, organelle communication, and network-level computation. This review intends to synthesize emerging frameworks that reposition neurodegenerative diseases (ND) as progressive breakdowns of interpretive cellular logic, rather than mere terminal consequences of protein aggregation or synaptic attrition. The discussion aims to provide a detailed mapping of how critical signaling pathways—including PI3K–AKT–mTOR, MAPK, Wnt/β-catenin, and integrated stress response cascades—undergo spatial and temporal disintegration. Special attention is directed toward the roles of RNA-binding proteins (e.g., TDP-43, FUS, ELAVL2), m6A epitranscriptomic modifiers (METTL3, YTHDF1, IGF2BP1), and non-canonical post-translational modifications (SUMOylation, crotonylation) in disrupting translation fidelity, proteostasis, and subcellular targeting. At the organelle level, the review seeks to highlight how the failure of ribosome-associated quality control (RQC), autophagosome–lysosome fusion machinery (STX17, SNAP29), and mitochondrial import/export systems (TIM/TOM complexes) generates cumulative stress and impairs neuronal triage. These dysfunctions are compounded by mitochondrial protease overload (LONP1, CLPP), UPR maladaptation, and phase-transitioned stress granules that sequester nucleocytoplasmic transport proteins and ribosomal subunits, especially in ALS and FTD contexts. Synaptic disassembly is treated not only as a downstream event, but as an early tipping point, driven by impaired PSD scaffolding, aberrant endosomal recycling (Rab5, Rab11), complement-mediated pruning (C1q/C3–CR3 axis), and excitatory–inhibitory imbalance linked to parvalbumin interneuron decay. Using insights from single-cell and spatial transcriptomics, the review illustrates how regional vulnerability to proteostatic and metabolic stress converges with signaling noise to produce entropic attractor collapse within core networks such as the DMN, SN, and FPCN. By framing neurodegeneration as an active loss of cellular and network “meaning-making”—a collapse of coordinated signal interpretation, triage prioritization, and adaptive response—the review aims to support a more integrative conceptual model. In this context, therapeutic direction may shift from damage containment toward restoring high-dimensional neuronal agency, via strategies that include the following elements: reprogrammable proteome-targeting agents (e.g., PROTACs), engineered autophagy adaptors, CRISPR-based BDNF enhancers, mitochondrial gatekeeping stabilizers, and glial-exosome neuroengineering. This synthesis intends to offer a translational scaffold for viewing neurodegeneration as not only a disorder of accumulation but as a systems-level failure of cellular reasoning—a perspective that may inform future efforts in resilience-based intervention and precision neurorestoration. Full article

Apelin-13, a neuropeptide, has been recognized for its neuroprotective properties. Our previous study found apelin-13 improves cognitive function in Alzheimer’s disease (AD) rats by inhibiting neuroinflammation through upregulation of BDNF/TrkB signaling pathway. However, the precise mechanism by which apelin-13 modulates BDNF remains unclear. Thus, this study aimed to unravel the specific regulatory mechanism by which apelin-13 regulates BDNF. Bilaterally intracerebroventricular injection with Aβ25–35 was used to establish an in vivo model of AD. For the generation of METTL3 KO rats, the Crispr/Cas9 method was applied. PC12 cells were treated with Aβ25–35 to establish an in vitro model of AD. The cognitive function of the rats was evaluated with the Morris water maze and the novel object recognition test. Hippocampal damage and neuron loss were detected through H&E and immunofluorescent staining. METTL3, BDNF, TrkB, and p-TrkB were examined by Western blotting. Inflammation-related cytokines, IBA1, GFAP, IL-1β, and TNF-α were detected by Western blotting, immunofluorescent staining, ELISA, and qRT-PCR. m6A modification level was evaluated through MeRIP. A flow cytometer was applied to evaluate cell apoptosis. Cell proliferation was examined using MTT. m6A methylation inhibitor DAA reverses the improvement effect of apelin-13 on cognitive function, hippocampal nerve damage, neuron loss, and neuroinflammation in Aβ25–35-treated rats. Further results showed that apelin-13 upregulated METTL3, BDNF-AS m6A methylation, inhibited BDNF-AS expression, and subsequently upregulated BDNF/TrkB signaling pathway and reduced neuroinflammation in in vivo and in vitro AD models in a dose-dependent manner. Knockdown of METTL3 abolished apelin-13’s improvement effect in AD rats. Apelin-13-mediated upregulation of METTL3 enhances neuroinflammation inhibition and BDNF/TrkB signaling pathway via m6A-dependent downregulation of lncRNA BDNF-AS, thus ameliorating AD. Our study offers novel insights into the pathogenesis of AD and identifies potential drug targets for its treatment. Full article

Miller–Dieker Syndrome (MDS) is a rare neurodevelopmental disorder caused by a heterozygous deletion of approximately 26 genes within the MDS locus of human chromosome 17. MDS, which affects 1 in 100,000 babies, can lead to a range of phenotypes, including lissencephaly, severe neurological defects, distinctive facial abnormalities, cognitive impairments, seizures, growth retardation, and congenital heart and liver abnormalities. One hallmark feature of MDS is an unusually smooth brain surface due to abnormal neuronal migration during early brain development. Several genes located within the MDS locus have been implicated in the pathogenesis of MDS, including PAFAH1B1, YWHAE, CRK, and METTL16. These genes play a role in the molecular and cellular pathways that are vital for neuronal migration, the proper development of the cerebral cortex, and protein translation in MDS. Improved model systems, such as MDS patient-derived organoids and multi-omics analyses indicate that WNT/β-catenin signaling, calcium signaling, S-adenosyl methionine (SAM) homeostasis, mammalian target of rapamycin (mTOR) signaling, Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling, and others are dysfunctional in MDS. This review of MDS integrates details at the clinical level alongside newly emerging details at the molecular and cellular levels, which may inform the development of novel therapeutic strategies for MDS. Full article

Kalanchoe pinnata is used in traditional medicine to treat cancer, as it contains flavonoids and phenols known to regulate key cellular processes associated with cancer. Breast cancer, the most common cancer among women globally, presents ongoing challenges in treatment. The discovery of m⁶A methylation and its regulation by methylosome proteins offers novel therapeutic avenues for cancer management. This study aimed to investigate the cytotoxic and epitranscriptomic effects of an aqueous extract from K. pinnata on MCF-7 (luminal A) and HCC1937 (triple-negative) breast cancer cells. Cell lines were treated with the aqueous K. pinnata extract, characterized by HPLC, for 72 h, followed by an assessment of cytotoxicity and migration. The expression of methylosome components METTL3 and FTO was measured using RT-PCR. m⁶A global methylation was assessed via colorimetry, and molecular docking studies were conducted. The results indicated that only HCC1937 cells exhibited altered migration capacity. This change was correlated in silico with the inhibition of METTL3 by luteolin and quercetin, constituents of the aqueous extract. METTL3, a methyltransferase, was overexpressed by scratch stimuli but was downregulated following K. pinnata treatment in both MCF-7 and HCC1937 cells. The FTO demethylase was overexpressed in both cell lines. In silico analysis suggested an interaction between FTO and compounds such as gallic acid and myricetin. Additionally, m⁶A global methylation decreased in MCF-7 cells but increased in HCC1937 cells, potentially affecting cell migration. Our findings indicate that K. pinnata influences both METTL3 and FTO, altering m⁶A methylation in a cell-type-dependent manner, with HCC1937 cells being particularly sensitive. Further research is required to elucidate the complete molecular mechanism of K. pinnata’s aqueous extract in breast cancer treatment. Full article

Nipah virus (NiV), a highly lethal zoonotic paramyxovirus, displays strain-specific pathogenicity, yet the molecular basis for this divergence remains elusive. Here, we identify N6-methyladenosine (m6A) modification as a pivotal regulator of NiV replication. Higher m6A methylation levels on viral genomic RNA and mRNAs are associated with the increased virulence observed in the NiV-Malaysia (NiV-M) strain compared to NiV-Bangladesh (NiV-B). Underlying this phenomenon, NiV infection orchestrates a reprogramming of the host m6A machinery by downregulating the methyltransferase METTL3 and the demethylase ALKBH5, while concurrently upregulating m6A reader proteins YTHDF1-3. Both METTL3 and ALKBH5 bind directly to NiV RNA, with METTL3 installing m6A to promote viral replication and ALKBH5 removing them to inhibit it. Strikingly, pharmacological inhibition of m6A modification markedly attenuates NiV replication in vitro and in vivo, underscoring the therapeutic potential of targeting the m6A pathway. Our study establishes m6A as a key determinant of NiV pathogenicity and provides a paradigm for host-directed antiviral strategies against high-risk RNA viruses. Full article

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is one of the side effects of bisphosphonate (BP) administration. Despite some preventive measures having been suggested, a definitive and effective treatment strategy for BRONJ remains to be established. Recent evidence has indicated that BPs dramatically impair the function of orofacial bone marrow stromal cells (BMSCs), which may contribute to the development of osteonecrosis. Thus, we hypothesized that recovery-impaired function of BMSCs at lesion sites could be beneficial in treating BRONJ. N6-methyladenosine (m6A) modification is the most common epigenetic modification and has been demonstrated to play a vital role in the modulation of BMSCs’ function. We detected the role of m6A modification in regulating the function of orofacial BMSCs under BP stimulation, and found that BPs led to a reduction in the global m6A methylation level, SAM level, and METTL3 expression in BMSCs during the osteogenic differentiation period. Meanwhile, betaine, a methyl group donor, effectively reversed the BP-decreased global m6A methylation level and SAM level in BMSCs, as well as rescuing the differentiation ability of impaired BMSCs. In the last part, we built a BRONJ rat model and supplemented rats with betaine via drinking water. The results showed that betaine successfully attenuated bone lesions and promoted wound healing in BP-injected rats, thereby providing new insight into future clinical treatment for BRONJ. Full article

Frataxin is a component of the iron–sulfur (Fe-S) cluster assembly complex in mitochondria, and deficiency is associated with Friedreich ataxia (FA). The yeast homolog Yfh1 resembles and cross-complements with its human equivalent, and frataxin bypass scenarios are of particular interest because they may point to strategies for treating FA. Here, we describe frataxin/Yfh1 bypass by overexpression of Rsm22, an assembly factor for the mitochondrial ribosome. Rsm22 overexpression in Yfh1-depleted yeast cells restored critical processes in mitochondria, including Fe-S cluster assembly, lipoic acid synthesis, iron homeostasis, and heme synthesis, to a significant extent. Formation of cytoplasmic Fe-S proteins was also restored, suggesting recovery of the mitochondrial ability to generate the (Fe-S)_int intermediate that is exported from mitochondria and is utilized for cytoplasmic Fe-S cluster assembly. Importantly, an essential component of the mitochondrial iron–sulfur cluster machinery, namely ferredoxin, was virtually absent in mitochondria lacking Yfh1, but it was recovered with Rsm22 overexpression. Interestingly, ferredoxin overexpression could offset some of the effects of Yfh1 depletion. Ferredoxin has recently been shown to bind to the cysteine desulfurase protein Nfs1 at the same site as Yfh1, in a conserved arginine patch on Nfs1, such that ferredoxin binding at this site may confer frataxin-bypass activity. Full article

Facioscapulohumeral muscular dystrophy (FSHD) is caused by the aberrant expression of the double homeobox 4 (DUX4) gene. In this study, an analysis of human FSHD muscle biopsies revealed differential expressions of six m6A regulators, including writers, readers and eraser proteins. In immortalized human FSHD myoblasts, we found higher levels of mRNA and protein expression of a major m6A regulator, methyltransferase-like protein 3 (METTL3), in comparison with myoblasts from unaffected siblings (UASbs). Quantification of the overall RNA m6A levels in the FSHD myoblasts revealed significant elevation compared with their UASb, which was reversed to UASb levels following treatment with an antisense oligonucleotide targeting the DUX4 mRNA. Using Oxford Nanopore direct-RNA sequencing, we mapped m6A across the transcriptome and identified genes harboring differential methylated m6A sites, including several involved in iron homeostasis. Western blot protein quantification showed that FSHD myoblasts had higher levels of ferritin-heavy chain-207 isoform and mitoferrin-1. In addition, our data showed elevation in mitochondrial ferrous iron in FSHD myoblasts. Our findings suggest that m6A RNA modifications play a pivotal role in FSHD pathophysiology and may serve as biomarker for this disease. Full article

Meat quality traits, particularly WHC and tenderness, are pivotal for consumer satisfaction and economic value in the sheep industry. However, their genetic regulatory mechanisms remain unclear. We used RNA-Seq and WGCNA to identify genes regulating WHC and tenderness. Sixty longissimus thoracis samples were classified into high/low WHC (HWHC vs. LWHC) and high/low tenderness (HTN vs. LTN) groups. Comparative transcriptomics identified 270 differentially expressed genes (DEGs) linked to WHC, enriched in pathways like the regulation of the ATP metabolic process and the inhibition of canonical Wnt signaling. Key DEGs (e.g., SORBS1, FOXO1, PDE4B, CDH1) correlated significantly with WHC-associated traits. For tenderness, 165 DEGs were identified, including LEP, FABP4, PLIN1, and GLP1R, enriched in PPAR signaling, fat cell differentiation, and cAMP signaling pathways. WGCNA revealed modules associated with WHC and tenderness, with hub genes (ATP2C1, GSKIP, PATL1, PPARA, CYLD) involved in ATP metabolism, lipid biosynthesis, and myofibril assembly. Tissue-specific gene integration prioritized muscle-enriched candidates (METTL21C and ACTC1) with strong trait correlations. Our findings unveil interconnected gene networks governing WHC and tenderness, highlighting some candidate genes as potential biomarkers for precision breeding. This study provides novel insights into the molecular determinants of meat quality, offering actionable targets to enhance mutton production sustainability and consumer appeal. Full article

N6-methyladenosine (m⁶A) is one of the most prevalent methylated modifications of mRNA in eukaryotes. This reversible alteration can directly or indirectly influence biological functions, including RNA degradation, translation, and splicing. This study investigates the impact of chronic morphine administration and varying withdrawal durations (1 day, 1 week, 4 weeks, and 12 weeks) on the m⁶A modification levels in brain regions critical to addiction development and persistence. Our findings indicate that in the prefrontal cortex, the m⁶A levels and METTL3 expression decrease, accompanied by an increase in FTO and ALKBH5 expression, followed by fluctuating, but statistically insignificant changes in methylation-regulating enzymes over prolonged withdrawal. In the striatum, reductions in m⁶A levels and METTL3 expression are observed at 4 weeks of withdrawal, preceded by non-significant fluctuations in enzyme expression and the m⁶A modification levels. In contrast, no changes in the m⁶A modification levels or the expression of related enzymes are detected in the hippocampus and the cerebellum. Our data suggest that m⁶A modification and its regulatory enzymes undergo region-specific and time-dependent changes in response to chronic morphine exposure and subsequent withdrawal. Full article

m⁶A methylation modification is an important genetic modification involved in biological processes such as sexual maturation, antibacterial, and antiviral in aquatic animals. However, few studies have been conducted in aquatic animals on the relationship between m⁶A methylation modification and autophagy-inflammation induced by lipid metabolism disorders. In the present study, a high-fat (HF) group and HF-MLP group (1 g mulberry leaf polysaccharides (MLPs)/1 kg HF diet) were set up. The mid-hind intestines of Megalobrama amblycephala juveniles from the two groups were collected for MeRIP-seq and RNA-seq after an 8-week feeding trial. The m⁶A peaks in the HF and HF-MLP groups were mainly enriched in the 3′ Untranslated Region (3′UTR), Stop codon, and coding sequence (CDS) region. Compared with the HF group, the m⁶A peaks in the HF-MLP group were shifted toward the 5′UTR region. ‘RRACH’ was the common m⁶A methylation motif in the HF and HF-MLP groups. Methyltransferase mettl14 and wtap expression in the intestines of the HF-MLP group were significantly higher compared with the HF group (p < 0.05). A total of 21 differentially expressed genes(DEGs) with different peaks were screened by the combined MeRIP-seq and RNA-seq analysis. Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis enriched BCL2 interacting protein 3 (bnip3) to autophagy–animal and mitophagy–animal signaling pathways, etc., and nucleotide-binding domain leucine-rich repeat protein 1 (nlrp1) was enriched to the Nucleotide-binding oligomerization domain (NOD)-like receptor signaling pathway. Combined MeRIP-seq and RNA-seq analysis indicated that the expression pattern of bnip3 was hyper-up and that of nlrp1 was hyper-down. Gene Set Enrichment Analysis (GSEA) analysis confirmed that the intestinal genes of HF-MLP group positively regulate lysosomal and autophagy–animal signaling pathways. In the present study, we demonstrated that m⁶A methylation modification plays a role in regulating autophagy-inflammatory responses induced by HF diets by MLPs, and further explored the molecular mechanisms by which MLPs work from the epigenetic perspective. Full article