Cellular lipid droplet (LD) turnover is essential for metabolic homeostasis in liver, and failures in LD clearance are increasingly linked to fatty liver disease. We describe a previously unrecognized mechanism of LD turnover and a human disorder caused by its disruption. A 2-year-old boy with metabolic dysfunction-associated steatotic liver disease (MASLD) was found by exome sequencing to carry an ultrarare homozygous C12ORF54 missense variant (c.134A>G; p.Q45R). We find that wild-type C12ORF54 is a conserved protein that binds LDs via a central amphipathic helix and tethers to lysosomes through an N-terminal helix interaction with the BORC subunit KXD1, enabling direct deposition of LDs into lysosomes. The p.Q45R substitution sterically destabilizes the amphipathic helix, abolishes KXD1 binding, prevents LD and lysosome targeting and blocks LD deposition. Proband cells accumulate LDs and acyl lipid species, lipotoxic stress due to excess ROS, and exhibit cell-cycle arrest and cell death. This study implicates defective direct lysosomal LD deposition as a cause of childhood-onset MASLD-like hepatic phenotype, and finds the C12ORF54-KXD1 interaction axis as a potential contributor to LD homeostasis in liver.
Circular RNAs (circRNAs) have emerged as stable post-transcriptional regulators that influence gene expression, cellular adaptation, and disease pathogenesis through mechanisms including microRNA (miRNA) interaction, RNA-binding protein modulation, and signaling-network regulation. Generated through the back-splicing process that produce covalently closed RNA loops, circRNAs exhibit remarkable stability, evolutionary conservation, and tissue-specific expression patterns, enabling them to function as miRNA sponges, protein scaffolds, transcriptional modulators, and, in some cases, translational templates. Increasing evidence indicates that dysregulated circRNA expression contributes to a broad spectrum of human diseases, highlighting their diagnostic and therapeutic potential. Among the molecular pathways influenced by circRNAs, Sirtuin 1 (SIRT1), an NAD+-dependent deacetylase and a modulator of metabolic homeostasis, stress adaptation, inflammation, autophagy, and aging, has emerged as a particularly important target. Recent studies have revealed that circRNAs regulate SIRT1 through complex post-transcriptional and signaling networks, thereby influencing cellular fate decisions in both malignant and non-malignant disorders. Importantly, the biological consequences of circRNA-mediated SIRT1 modulation appear highly context-dependent, with protective or pathogenic effects varying according to tissue type, metabolic state, and disease stage. In this review, we provide a comprehensive and integrative discussion of the circRNA-SIRT1 regulatory axes across diverse pathological conditions, from common metabolic disorders to life-threatening cancers. Beyond summarizing current evidence, we propose the circRNA-SIRT1 network as a context-dependent post-transcriptional regulatory network linking non-coding RNA (ncRNA) biology to immunometabolic and stress-response pathways. We further discuss emerging translational opportunities and circRNA-targeted therapeutics, emphasizing the potential of this regulatory axis as a promising platform for precision diagnostics and disease-specific therapeutic interventions.
Parkinson's disease (PD), the world's second most prevalent neurodegenerative disorder, is characterized by midbrain substantia nigra dopaminergic (DA) neuron loss, neuroinflammation, and α-synuclein aggregation. c-Cbl, a RING-finger E3 ubiquitin ligase highly expressed in the substantia nigra and striatum, regulates neuroinflammation via the NF-κB pathway. Prior studies showed that reduced c-Cbl expression triggers microglia-mediated neuroinflammation in LPS- and MPTP-induced PD models, but whether c-Cbl overexpression suppresses NLRP3 inflammasome activation to alleviate PD-related neuroinflammation remains unclear. We established LPS-induced chronic neuroinflammatory and Parkin-deficient PD models, confirming downregulated c-Cbl expression. In vitro, LV-c-Cbl overexpression in PC12 cells mitigated NLRP3 activation, autophagy dysfunction, and DA neuron loss. In vivo, stereotaxic AAV-c-Cbl injection in LPS model mice and Parkin+/- mice inhibits NLRP3 inflammasome activation via the NF-κB signaling pathway, autophagic impairment, DA neuron damage, and motor dysfunction. Collectively, c-Cbl is a promising therapeutic target for PD.
Gliomas and particularly glioblastomas, represent the most aggressive and treatment-resistant brain tumours. Current standard treatments, including surgical resection, radiotherapy and chemotherapy, offer only limited long-term survival benefits. The highly immunosuppressive tumour microenvironment that characterizes gliomas enables immune evasion and limits the effectiveness of anti-tumour immune response, indicating the urgent need for identification of tumour antigens with clinical relevance to improve current immunotherapeutic strategies and enhance glioma immunogenicity. Immunopeptidomics, a mass spectrometry-based identification of peptides presented by HLA molecules, is a growing field of research for understanding the immunosurveillance of gliomas. By enabling the direct identification of naturally presented HLA-bound peptides from tumour tissue for T cell recognition, immunopeptidomics provide valuable insights into tumour antigen presentation and immune targeting. This review highlights the emerging role of immunopeptidomics in gliomas, covering the mechanisms of antigen processing and presentation by HLA class I and II molecules, the identification of glioma-associated antigens, the development of personalised peptide vaccines and the discovery of new targets for T cell-based immunotherapies. The potential of plasma-derived soluble HLA (sHLA) peptidomes as minimally invasive liquid-biopsy biomarkers is further discussed for disease monitoring and response to treatment. Overall, immunopeptidomics are foreseen as a powerful tool for the discovery of new tumour antigens leading to the development of more effective personalised glioma immunotherapies.
Rho GTPase-activating protein 10 (ARHGAP10) is recognized as a tumor suppressor, yet the functional impact of its alternative splicing isoforms on breast cancer metastasis remains unclear. This study aimed to elucidate the role and regulatory mechanism of ARHGAP10 exon 21 skipping in breast cancer progression. Our research results indicate that in metastatic breast cancer cells, the full-length isoform ARHGAP10-L is downregulated, whereas the truncated ARHGAP10-S is upregulated. The RNA-binding protein HNRNPA0 directly binds to intron 21 of ARHGAP10 pre-mRNA, promoting exon-21 skipping and ARHGAP10-S production. Functionally, ARHGAP10-L and ARHGAP10-S exert opposing effects on breast cancer cell malignancy: ARHGAP10-L suppresses migration, invasion, and lung metastasis, whereas ARHGAP10-S promotes these aggressive phenotypes. Moreover, ARHGAP10-S exhibits enhanced binding to CDC42 and is associated with increased AKT phosphorylation. In a nude mouse model, HNRNPA0 drove lung metastasis by upregulating ARHGAP10-S. These findings establish the HNRNPA0-ARHGAP10 splicing axis as a key regulator of breast cancer metastasis, in which ARHGAP10-S promotes progression via the AKT pathway whereas ARHGAP10-L acts as a tumor suppressor, highlighting the therapeutic potential of targeting this splicing event to combat metastasis.
In homeotherms, heat loss and the need for heat production are increased in small animals compared with large ones, and mitochondria are the primary organelles responsible for heat production in animals. Because of this, in animals of different body sizes, mitochondria may differ in their sensitivity to temperature and ability to produce heat via ATP uncoupling. Here, we used primary fibroblast cells isolated from large breed puppies and senior dogs, and small breed puppies and senior dogs to determine whether mitochondria across body sizes and ages in dogs function similarly, or whether smaller breeds tend to be more uncoupled and temperature sensitive due to their whole-animal phenotype of low body temperature and high mass specific metabolic rate. We compared metabolic rates in cells exposed to 37 and 40 °C to determine thermal sensitivities. We found that basal respiration and proton leak increased across all size and age classes in the 40 °C group, while coupling efficiency and spare respiratory capacity decreased, indicating that higher temperatures uncouple mitochondria in dogs, but body size does not affect temperature sensitivity. Additionally, to elucidate mechanistic differences in uncoupling, we treated cells with the UCP2 inhibitor genipin and found that genipin-treated cells increased proton leak in small senior dogs, but reduced proton leak in large puppies. The different responses to UCP2 inhibition correlate with metabolomic differences previously found in dogs of different size and age classes, and our data suggest that the role of UCP2 is dependent on the metabolic phenotype of a cell.
Cigarette smoking remains a dominant, preventable driver of cancer morbidity and mortality, and clinical outcomes in smokers remain disproportionately poor even with targeted and immune therapies. Beyond mutagenesis, cigarette smoke (CS) remodels cell state by promoting stem-like programs and enriching cancer stem cells (CSCs), a subpopulation with self-renewal capacity and therapy resistance that drives tumor heterogeneity, metastasis, and treatment failure. CS activates stemness-linked pathways, including Wnt/β-catenin, Notch, Hedgehog/GLI, NF-κB, PI3K/AKT/mTOR, and TGF-β, and remodels the tumor microenvironment to further support CSC properties. While CS effects on lung tissue are well documented, its role in CSC induction at distant organs remains less understood. In this narrative, mechanistically organized review, we examine in vitro, in vivo, and clinical evidence linking CS exposure to CSC induction in primary lung cancer and secondary cancers at distant sites. We propose a unifying framework in which CS acts as a stemness-conditioning exposure that couples oncogenic signaling, epigenetic rewiring, and microenvironmental remodeling to stabilize therapy-evasive CSC states, converging on shared endpoints across tissues via tissue-specific intermediate signaling, and highlight therapeutic vulnerabilities arising from this framework.
Dysregulation of the ubiquitin-proteasome system contributes to hepatocellular carcinoma (HCC), but how deubiquitination is linked to transcriptional regulation and alternative splicing remains unclear. In this study, proteomic analysis identified E2F4 as a PSMD14-interacting protein. Co-immunoprecipitation and ubiquitination assays showed that PSMD14 removed K48-linked polyubiquitin chains from E2F4, thereby reducing its degradation and increasing its protein stability. Stabilized E2F4 directly bound to the PHF5A promoter and promoted PHF5A transcription. As a component of the spliceosome, PHF5A regulated alternative splicing in HCC cells, including exon 3 skipping of NASP and exon 3 inclusion of POLA1. Silencing PSMD14, E2F4, or PHF5A inhibited HCC cell proliferation, whereas re-expression of the corresponding downstream factors partially restored cell growth, supporting a functional PSMD14-E2F4-PHF5A regulatory axis. Treatment with the proteasome-associated inhibitor O-phenanthroline (OPA) reduced E2F4 and PHF5A expression, altered NASP and POLA1 splicing, and suppressed xenograft tumor growth. Moreover, overexpression of E2F4 or PHF5A partially reversed OPA-induced splicing changes and growth inhibition in vitro. These findings identify a PSMD14-E2F4-PHF5A pathway that connects protein deubiquitination with transcriptional regulation and alternative splicing, and suggest that this pathway may represent a potential therapeutic vulnerability in HCC.
Gastroesophageal reflux disease (GERD) is a digestive disease characterized by endoplasmic reticulum stress (ERS) imbalance and oxidative stress-induced cellular injury. However, the key ERS-related regulators involved in GERD progression remain unclear. Here, we identified PCK2 as a novel GERD-associated ERS regulator and explored its role and underlying mechanisms in GERD development. Bioinformatics analysis of the GEO dataset GSE148381 identified four overlapping ERS-related candidate genes in GERD tissues. Among these candidates, PCK2 was selected based on its consistent upregulation in ABS-treated HET-1 A cells, as confirmed by RT-qPCR and western blotting, with a 1.2-fold increase in mRNA expression and a 2.67-fold increase in protein abundance compared with control cells. Functional studies demonstrated that PCK2 silencing attenuated ERS activation by reducing ATF6, PERK, p-PERK, CHOP, and XBP1 expression. PCK2 knockdown markedly alleviated oxidative stress, reducing ROS and MDA levels by approximately 91% and 34%, respectively, decreasing apoptosis by approximately 36%, and improving cell viability, whereas PCK2 overexpression exerted opposite effects. In vivo, PCK2 knockdown alleviated esophageal injury and suppressed ERS responses. Mechanistically, Gene Set Enrichment Analysis revealed enrichment of PCK2-associated genes in the MAPK pathway, and further experiments showed that PCK2 promoted p38 MAPK activation through enhanced p38 phosphorylation. Pharmacological inhibition of p38 signaling with SB203580 abolished PCK2-induced ERS, oxidative stress, and apoptosis in HET-1 A cells. Collectively, our findings indicate that PCK2 acts as a potential therapeutic target in GERD by promoting p38 MAPK activation, thereby exacerbating ERS, oxidative stress, and apoptosis.
The IQ motif and SEC7 domain-containing protein 2 (IQSEC2) is a guanine nucleotide exchange factor (GEF) for ARF family small GTPases and is encoded by the IQSEC2 gene located on chromosome Xp11.22. More than 120 pathogenic variants in IQSEC2 have been identified in patients with neurodevelopmental disorders. In this study, we aimed to clarify the role of IQSEC2 during neonatal mouse dentate gyrus development using in vivo electroporation. Electroporation of a GFP expression vector together with a short hairpin RNA (shRNA) targeting IQSEC2 caused dentate granule neurons to stop at the boundary between the granule cell layer and the hilus (GCL/hilus). IQSEC2-deficient dentate granule cells exhibited increased distal dendritic complexity compared with control cells. IQSEC2 knockdown also reduced spine head diameter without affecting spine density. In contrast, exogenous IQSEC2 expression increased proximal dendritic complexity in neonatal dentate granule cells. We examined the ARF selectivity of IQSEC2 GEF activity and found that IQSEC2 activates ARF1, ARF3, and ARF6. Functional analyses revealed that ARF1 knockdown also confined dentate granule cells to the GCL/hilus region, which was consistent with the observation following IQSEC2 knockdown. In contrast, knockdown of ARF3 or ARF6 had no significant effect. Together, these results suggest that the IQSEC2 and ARF1 play a critical role in regulating neuronal positioning and dendritic development in the neonatal dentate gyrus.
Integral membrane proteins (IMPs) are challenging, yet highly relevant targets for structural biology. Selection of the appropriate membrane mimic environment necessitates extensive optimization using a combination of biochemical and biophysical techniques. We report here on the expanding role of mass photometry (MP) as an in-solution technique to enable single-particle analysis of IMPs. To showcase MP versatility, we present here a selection of examples of MP applications for IMP analysis, using nicotinic acetylcholine receptor (nAChR) extracted from Torpedo marmorata as case study, together with additional literature examples. We further illustrate how MP supports the screening of purification conditions, and the quality control of samples prior to cryo-electron microscopy grid preparation or native mass spectrometry. The benefits of MP for IMP characterization are illustrated through its ability to quantify single-molecule populations, study membrane biomolecular assemblies, and characterize membrane-associated phenomena from very low amounts of starting material. MP therefore stands out as a unique biophysical tool that combines rapid analysis with broad adaptability to most solubilizing environments, enabling simultaneous relative quantification of all detected species in a highly user-friendly manner.
OBJECTIVE:This study aims to investigate the role and molecular mechanism of USP22 in diabetic retinopathy (DR), focusing on its regulation by histone lactylation and a positive feedback loop with HIF-1α. METHODS:A DR mouse model was established via intraperitoneal injection of STZ, and in vitro DR models were induced using high glucose (HG) treatment in ARPE-19 and mRPE. Cell damage was assessed through CCK-8, EdU staining, and other experiments, while retinal damage was evaluated via H&E staining and TUNEL staining. RESULTS:In DR models both in vivo and in vitro, USP22 expression was significantly elevated. Knockdown of USP22 alleviated retinal damage in DR mice and reduced injury in ARPE-19 and mRPE cells exposed to HG, an effect associated with suppressed glycolysis. HIF-1α was also upregulated in DR. Co-IP assays confirmed that USP22 stabilizes HIF-1α through deubiquitination. Overexpression of HIF-1α partially reversed the inhibitory effects of USP22 knockdown on glycolysis and cellular damage under HG conditions. Furthermore, ChIP analysis revealed that lactate, a glycolytic product, promotes USP22 transcription and expression via H3K18la modification, forming a glycolysis/H3K18la/USP22/HIF-1α positive feedback loop. HIF-1α overexpression reversed the glycolysis inhibitor 2-DG-induced suppression of USP22 H3K18la modification and expression in HG-exposed cells, while attenuating the protective effect of 2-DG against cellular injury. Consistently, in vivo, knockdown of USP22/HIF-1α or 2-DG treatment downregulated USP22, Pan Kla, and H3K18la in DR retinas, while ameliorating retinal structural damage and apoptosis. CONCLUSION:Our study reveals that a "glycolysis/H3K18la/USP22/HIF-1α" positive feedback loop exists in DR, promoting disease progression.
Pancreatic cancer (PC) is a highly lethal malignancy characterized by aggressive progression and limited treatment options. Current standard-of-care treatments only confer marginal survival benefits, highlighting an urgent unmet clinical need to identify novel actionable targets and mechanism-driven therapeutic regimens. Focal adhesion kinase (FAK, encoded by PTK2) is frequently dysregulated across a broad spectrum of cancers and tightly associated with malignant tumor phenotypes, yet its precise clinical relevance and druggable potential in PC remain incompletely elucidated. This study systematically evaluated the diagnostic and prognostic value of PTK2/FAK in PC, and dissected the anti-tumor efficacy and underlying molecular mechanism of the selective FAK inhibitor Defactinib. We confirmed that PTK2 was significantly overexpressed in PC tissues, serving as a high-accuracy diagnostic biomarker with an AUC of 0.959 and an independent risk factor for unfavorable prognosis. PTK2-high tumors exhibited marked enrichment of the PI3K/AKT oncogenic signaling pathway, and MYC was validated to directly transcriptionally upregulate PTK2, where patients with concurrent MYC-high and PTK2-high tumors showed the worst clinical outcomes. Using in vitro functional assays and two distinct genetically engineered mouse models, we demonstrated that Defactinib potently suppressed tumor proliferation and induced caspase-3-dependent apoptosis via blockade of the PI3K/AKT cascade. Notably, Defactinib also triggered ULK1-mediated compensatory protective autophagy, and co-administration with the autophagy inhibitor chloroquine effectively abrogated this process to substantially amplify the anti-tumor effect. Our findings validate PTK2 as a clinically meaningful prognostic biomarker and promising therapeutic target, providing robust new preclinical evidence to support the clinical translation of PTK2-targeted combination therapies for PC.
The chemokine CCL20/MIP3α plays an important role in the migration of dendritic cells and several lymphocytes. This 70-residue protein is also implicated in various diseases, such as rheumatoid arthritis, psoriasis, sepsis and numerous forms of cancer. In addition, as the most basic human chemokine, CCL20 also displays direct antimicrobial and antibiofilm activities. The binding and oligomerization of chemokines to cell surface glycosaminoglycans (GAG) can play an important role during receptor activation; therefore we have studied the interactions of CCL20 with fondaparinux. This anticoagulant drug is a uniform sulfated linear pentasaccharide that structurally closely resembles the heterogenous low molecular weight heparins that have often been used to study GAG-protein binding in solution. Using multidimensional multinuclear NMR spectroscopy, we could map out the distinct GAG/fondaparinux binding sites on the monomeric (pH 5.5) and dimeric (pH 7.5) forms of the CCL20 protein surface. In the second part of this study, we showed that CCL20-(51-70), the recombinant 20-residue carboxyterminal helical peptide of CCL20, interacted weakly with fondaparinux. We also surveyed several host-defence properties of this peptide. In comparison to several other well-characterized peptides, CCL20-(51-70) displayed potent antibiofilm and antimicrobial activities against a pathogenic Gram-positive Staphylococcus aureus MRSA strain. It also displayed somewhat lower activities against the Gram-negative Pseudomonas aeruginosa PAO1 strain. These results highlight the potential of CCL20-(51-70) as a potent host-defence peptide, that could play a role in eradicating bacterial biofilms, particularly for Gram-positive pathogenic bacteria.
Sterol Regulatory Element-Binding Protein 2 (SREBP-2) is a core transcription factor that regulates de novo cholesterol synthesis. Targeting the SREBP pathway is regarded as a potential strategy for treating metabolic diseases such as Type 2 Diabetes Mellitus (T2DM). At present, natural specific and effective modulators of this pathway are still very scarce. We identified a novel nonapeptide ST2b from the vine of the medicinal sweet potato Ipomoea batatas L. cv. Simon 1, and its amino acid sequence is GSFKMEGKR. In vitro experiments have shown that ST2b can significantly promote glucose uptake in insulin-resistant HepG2 cells and improve disorders of glycolipid metabolism. In a mouse model of T2DM induced by streptozotocin and a high-fat, high-sugar diet, intragastric ST2b reduced fasting blood glucose and serum insulin levels, improved glucose tolerance and insulin sensitivity, normalized lipid metabolism, and protected metabolic organs. ST2b binds to INSIG-1, stabilizing it by inhibiting degradation, enhancing INSIG-1 interaction with SCAP, blocking SREBP-2 activation, reducing cholesterol synthesis gene transcription. ST2b from sweet potatoes shows promise as a T2DM treatment by inhibiting the SREBP-2 pathway, suggesting its potential as a therapeutic agent or functional food for T2DM.
Coactivator-associated arginine methyltransferase 1 (CARM1/PRMT4) is a signal-responsive epigenetic regulator that couples oncogenic and stress signals to chromatin, transcription, RNA processing, metabolism, and genome maintenance. Its effects arise from both asymmetric arginine methylation of histone and non-histone substrates and methyltransferase-independent scaffolding activities. This review critically synthesizes the structural basis, substrate networks, methylarginine readers, and cancer-contextual functions of CARM1. We propose that its apparently opposing oncogenic and tumor-suppressive activities are determined by lineage-specific substrates, regulatory post-translational modifications, cofactor and chromatin availability, and stage- or microenvironment-dependent stress signals. We further evaluate CARM1-directed therapy using an evidence-graded framework. Catalytic inhibitors such as TP-064 and EZM2302 differ in binding mode and substrate coverage, whereas emerging degraders can remove scaffolding functions but remain constrained by delivery, E3-ligase heterogeneity, pharmacokinetics, and therapeutic-window uncertainties. Biomarker-guided synthetic-lethal and immunotherapy combinations may therefore offer the most tractable route to clinical translation. This framework positions CARM1 as a context-conditioned signal-to-chromatin translator rather than a uniformly druggable oncogene.
Regulation of Na+,K+-ATPase activity plays a critical role in maintaining ionic homeostasis and Ca2+-dependent contractility in smooth muscle, yet the contribution of selective sodium pump modulators to myometrial function remains insufficiently understood. In this study, we investigated the effects of calix[4]arene C-1220 (25,27-dipropoxycalix[4]arene-bis-N-tolylsulfonylaminomethylphosphonic acid) and its structural analogue C-99 on ATP-hydrolyzing activities, intracellular Ca2+ dynamics, mitochondrial function, and contractile behavior of uterine smooth muscle. Enzymatic assays showed that C-1220 is a highly potent and selective inhibitor of Na+,K+-ATPase (IC₅₀ = 48 ± 2 nM) without influencing other ATPases in the plasma membrane. Confocal imaging demonstrated that C-1220 elevates cytosolic Ca2+ in myocytes, whereas flow cytometry and Ca2+-accumulation assays indicated that mitochondrial membrane polarization and matrix Ca2+ levels remain unaffected. Tensometric measurements revealed that both C-1220 and C-99 enhance spontaneous contractions and force-, velocity-, and impulse-related mechanokinetic parameters; however, normalization of velocity parameters suggests that these changes do not reflect direct modulation of Ca2+-transporting systems. Comparative analysis supports the conclusion that inhibition of Na+,K+-ATPase and consequent disturbance of Na+/Ca2+ exchange underlie the contractile activation induced by both compounds. These findings provide new insights into membrane mechanisms governing electro- and pharmacomechanical coupling in uterine smooth muscle and highlight C-1220 as a useful molecular tool for probing Na+,K+-ATPase-dependent Ca2+ regulation.
Despite advances in current therapeutic strategies, osteosarcoma remains a highly aggressive malignancy with limited treatment options. Rutaecarpine (Rut), an indolopyridoquinazolinone alkaloid with selective cyclooxygenase-2 inhibitory activity, has been reported to possess diverse pharmacological properties; however, its anti-osteosarcoma mechanisms remain poorly defined. Here, we examined the anti-tumor activity of Rut and the signaling pathways underlying its biological effects. Rut reduced MG63 cell viability in a concentration-dependent manner and promoted apoptotic cell death, as demonstrated by TUNEL staining and changes in apoptosis-related proteins. Rut also impaired cell-cycle progression and induced reactive oxygen species-mediated mitochondrial dysfunction, accompanied by modulation of the NRF2/HO-1 pathway and autophagic responses. Proteome profiling identified PRAS40 as a major signaling component associated with the cellular response to Rut. Consistent with this finding, Rut suppressed PRAS40 phosphorylation, leading to activation of GSK3β-associated signaling and subsequent inhibition of cell migration, invasion, extracellular matrix degradation, and anchorage-independent colony formation through reduced expression of MMP-2, MMP-9, and MMP-13. The biological relevance of these findings was further supported using a newly established ex vivo calvaria-osteosarcoma metastasis model, in which Rut attenuated tumor-associated bone destruction while preserving newly formed bone, collagen matrix organization, and the viability of osteoblasts and osteocytes along the periosteal surface. Overall, the present findings suggest that Rut suppresses osteosarcoma progression by modulating the PRAS40-associated signaling network and supports its potential as a therapeutic agent for osteosarcoma-associated bone destruction.
N6-methyladenosine (m6A) is a prevalent epitranscriptional modification in RNA that is crucial for RNA metabolism and biogenesis. Accumulating evidence reveals a complex interplay between m6A and protein post-translational modifications (PTMs)-covalent additions of chemical groups or structural alterations to nascent proteins during or after biosynthesis. This crosstalk involves in disease development and drug response by altering protein properties and functions. However, comprehensive discussion about the roles and mechanisms of m6A and PTMs crosstalk is limited. Here, we present an up-to-date review of this emerging and complex interplay in disease and therapeutic response. We first summarize the crosstalk between m6A and PTMs such as ubiquitination, lactylation, acetylation, phosphorylation, and methylation, organizing our discussion around the three major regulatory factors m6A writers, erasers, and readers. Next, we explore the mechanism of m6A-PTMs crosstalk involved in the pathogenesis and development of diseases, including various cancers, metabolic disorders, and inflammatory diseases. Moreover, we discuss the role of m6A-PTMs crosstalk in drug response, focusing on chemotherapy drugs. In summary, this review provides a framework for understanding the regulatory networks of m6A-PTMs crosstalk in disease pathogenesis, development, and therapeutic response, highlighting potential treatment strategies based on this interplay and suggesting future research directions.
The metamorphosis of flatfishes involves a significant transformation from a pelagic larval stage to a benthic juvenile stage. This process is driven by thyroid hormone signaling and involves extensive morphological and functional remodeling. While the regulation of gene expression is central to this process, the epigenetic mechanisms coordinating these transitions remain poorly understood. Although DNA methylation has been implicated in vertebrate metamorphosis, its role in coordinating the epigenetic regulation of flatfish brain metamorphosis remains largely unexplored. In this study, we examine the epigenetic and transcriptional dynamics of the brain, a critical regulator of metamorphosis, by analyzing chromatin accessibility, DNA methylation and transcriptomic profiles across three developmental stages (pre-metamorphosis, metamorphic climax and post-metamorphosis) in turbot (Scophthalmus maximus). We identify widespread DNA methylation remodeling during metamorphosis, characterized by dynamic changes in DNA methylation. Differentially methylated regions (DMRs) exhibit a bimodal distribution at the pre-metamorphic stage, shift toward intermediate methylation levels at the metamorphic climax, and return to a bimodal pattern following metamorphosis. Notably, DMRs are predominantly associated with open chromatin regions and are significantly enriched at CpG islands. Furthermore, DNA methylation levels near transcription start sites are inversely related to gene expression, suggesting a regulatory role in transcriptional control. Collectively, our findings reveal dynamic epigenetic remodeling in the brain during flatfish metamorphosis, provide insights into how DNA methylation contributes to the coordination of developmental transitions, and extend current knowledge of vertebrate developmental epigenetics by providing the first integrative analysis of DNA methylation, chromatin accessibility, and transcriptional regulation during flatfish brain metamorphosis.
