Cellular and Molecular Life Sciences最新文献

Epitranscriptomics modifications play an important role in sex-dependent biological phenomena. N6-adenosine methylation (m6A), the most prevalent epitranscriptomics modification in eukaryotic mRNA, participates in regulating various sex-specific physiological processes. Here, we generated METTL4 knockout mice lacking methyltransferase-like 4, which mediates m6A. Behavioral analyses revealed that only female METTL4^-/- mice exhibited pain hypersensitivity, with subsequent experiments showing the involvement of METTL4-mediated m6A in this sex-differentiated biological phenotype. Further exploration demonstrated that this sex-specific pain hypersensitivity is closely associated with sex-dependent expression of uncoupling protein 2 (UCP2) in synapses. Specifically, elevated UCP2 expression in METTL4^-/- female mice enhances the efficiency of synaptic transmission by modulating mitochondrial energy metabolism at synapses. Collectively, this study identifies a distinct pathway mediated by METTL4-driven m6A modification, providing critical insights into the molecular basis of sex-specific differences in pain transmission. These findings also highlight the potential of targeting METTL4 for sex-differentiated pain management strategies in clinical settings.

The accumulation of HIFs regulated by the PHD-pVHL pathway represents the classical mechanism that transcriptionally mediates cellular adaptation to hypoxia. Extensive hypoxic stress activates cell death. Comprehensive understanding the mechanisms of hypoxia-induced cell death is essential for treatment of several diseases. Here, we revealed that β-TrCP1 degradation is essential for hypoxia-induced cell death and tissue injury. Hypoxia promotes β-TrCP1 degradation via proteasome pathway in HIFs-independent manner, and SMURF2 is identified as the corresponding E3 ligase. Additionally, acetylation of β-TrCP1 decreases after hypoxia, which is required for β-TrCP1 degradation. Tip60 establishes the acetylation of β-TrCP1 under normoxic conditions and is prolyl-hydroxylated by PHD2. Prolyl Hydroxylation stabilizes Tip60 under normoxic conditions, while hypoxia promotes the degradation of Tip60 by decreasing its prolyl hydroxylation. HDAC8 catalyses the deacetylation of β-TrCP1, which is enhanced after hypoxia. Loss of β-TrCP1 acetylation after hypoxia promotes the binding of SMURF2 to β-TrCP1 and its degradation. p53 is a substrate of β-TrCP1, and loss of β-TrCP1 upon hypoxia results in the accumulation of p53, which is responsible for hypoxia-induced cell death and tissue injury. Thus, this study illustrates a previously unappreciated posttranscriptional hypoxia-responsive mechanism constituted by PHD2-Tip60-HDAC8-SMURF2-β-TrCP1 degradation axis to promote p53 accumulation to mediate cell death and tissue injury.

Endometriosis is a hormone dependent disease that often accompanies infertility. At present, the incidence rate of endometriosis is on the rise, but its pathogenesis and the mechanism leading to fertility reduction are still unclear. Here, we report that protein arginine methyltransferase 3 (PRMT3) is crucial for endometriosis. PRMT3 damages the decidualization of stromal cells in endometriosis. Mechanistically, PRMT3 interacts with Forkhead Box O1 (FOXO1) to mediate methylation of its arginine site at position 253, and promotes its degradation while inhibiting its nuclear translocation. Interestingly, the arginine methylation of FOXO1 by PRMT3 inhibits decidualization through oxidative stress. Furthermore, in our animal experiments, we find that SGC707, a PRMT3 inhibitor, inhibits the occurrence of endometriosis, promotes deciduoma formation, and improves embryonic development. Taken together, PRMT3 may be a promising target for treating endometriosis and improving infertility related to endometriosis.

Objective: Ulcerative colitis (UC) is an inflammatory bowel disease that lacks satisfactory treatment. This study aimed to investigate the role of bone marrow mesenchymal stem cell-derived exosomal circHECTD1 (Exo-circHECTD1) in UC and its mechanism of action.

Methods: An inflammatory model was created using LPS-stimulated MODE-K cells and an UC mouse model was established using dextran sodium sulfate (DSS). Cell proliferation was assessed using CCK-8. Apoptosis and Th17/Treg cell differentiation were analyzed by flow cytometry. Inflammatory factors were detected using ELISA. FITC fluorescence intensity was measured to evaluate permeability. m⁶A modification and molecular binding were detected using immunoprecipitation methods. Luciferase reporters were used to evaluate METTL3 promoter activity. RT-qPCR was used to detect RNA expression and western blotting was used to detect METTL3, CTCF, claudin1, and tight junction proteins (ZO-1, occludin).

Results: Exo-circHECTD1 enhanced viability and permeability and reduced apoptosis and inflammation factor levels in LPS-treated MODE-K cells. Moreover, it reduced the Th17/Treg ratio, regulated gut microbiota, and promoted the recovery of mice with DSS-induced UC. Claudin1 knockdown reversed the protective effect of Exo-circHECTD1 on UC models. CircHECTD1 binds to CTCF, which binds to the METTL3 promoter and promotes METTL3 promoter activity. METTL3 upregulates the level of claudin1 m⁶A modification and inhibits claudin1 expression. CTCF or METTL3 knockdown alleviated LPS-induced MODE-K cell damage.

Conclusion: Exo-circHECTD1 inhibits METTL3 transcription by binding to CTCF to reduce claudin1 m⁶A modification and promote claudin1 expression, thereby regulating the balance of gut microbiota and Th17/Treg cells and alleviating UC.

Background: Atherosclerosis is a chronic vascular inflammatory disease caused by multiple factors. Anti-inflammatory treatment is an effective approach to treat atherosclerosis. Talin1 is a cell membrane-associated cytoskeletal protein that is widely expressed in mammals and plays essential roles in angiogenesis and endothelial cell barrier function. However, the role of Talin1 in atherosclerosis and the related mechanisms remains unclear.

Methods: ApoE-KO mice were subjected to partial carotid artery ligation to establish an atherosclerosis model, and the expression of Talin1 in atherosclerotic plaques was verified in vivo. Human umbilical vein endothelial cells (HUVECs) and aortic endothelial cells (HAECs) were treated with tumour necrosis factor α (TNF-α) (10 ng/mL) and subjected to low oscillatory shear stress (OSS) (approximately ± 4 dyn/cm2) to establish cellular inflammation models. A lentivirus was used to regulate Talin1 expression in HUVECs and HAECs.

Results: Talin1 levels were increased in the serum of subjects with coronary heart disease (CHD) compared with those without CHD. We also found that Talin1 levels were increased in the serum of ApoE-KO mice in the operation group compared with the sham operation group. In addition, Talin1 expression was increased in endothelial cells in atherosclerotic plaques. In addition, neither TNF-α nor OSS promoted inflammation in endothelial cells with Talin1 knockdown. Moreover, we found that TNF-α and OSS could activate Piezo1 to mediate Ca²⁺ influx and subsequently activate Talin1 to regulate YAP and promote inflammation.

Conclusions: The results of this study suggest that Talin1 plays a vital role in endothelial inflammation and may be a novel anti-inflammatory therapeutic target for atherosclerosis.

D-aspartate is an endogenous agonist of NMDA and mGlu5 receptors, with a distinctive spatiotemporal expression profile that peaks in the prenatal and early postnatal brain. This suggests a critical role for D-aspartate metabolism in modulating neurodevelopmental processes linked to glutamatergic neurotransmission. However, the precise mechanisms through which D-aspartate exerts its effects remain unclear. To elucidate the molecular pathways orchestrated by early D-aspartate signalling, we employed a knock-in mouse model characterized by constitutive D-aspartate depletion due to the prenatal expression of its degradative enzyme, D-aspartate oxidase. Using an advanced quantitative proteomic approach based on Tandem Mass Tag isobaric labelling and nano-liquid chromatography coupled with high-resolution tandem mass spectrometry, we investigated the proteomic variations induced by D-aspartate depletion during postnatal brain development, comparing Ddo knock-in mice with their wild-type littermates. Our findings reveal that D-aspartate modulates the neonatal expression of proteins involved in glutamatergic neurotransmission, nervous system development, and cytoskeleton organization. Moreover, proteomic analysis identified a subset of D-aspartate-regulated proteins mapping molecular pathways associated with autism spectrum disorder and schizophrenia. These findings offer new perspectives on the complex protein networks influenced by D-aspartate metabolism in the developing brain and highlight its potential impact on cerebral function in health and psychiatric disorders.

Human peripheral blood stem cells (PBSC) that have been most frequently used for repair or regeneration in ischemic cardiovascular disease (CVD) showed limitations in their efficacy. We previously reported that angiopoietin-1 (Ang1) is the cell-priming agent to enhance the vasculogenic potential of PBSC. The limitation was the difficulty to produce Ang1 protein with high efficiency. In this study, we engineered Ang1 structure and made FVA3-Ang1 by adding VASP and COMP sequence for stable tetramer formation as well as FLAG sequence for purification in large scale production and a signal peptide derived from influenza A virus (IAV) for better protein expression. FVA3-Ang1 showed stronger effect on endothelial cells than naïve Ang1 or COMP-Ang1 in terms of gene expression of Ang1, Ang2, VEGFA, FGF2, and KDR, as well as phosphorylation of Tie2, ERK, and Akt. Then we primed PBSC with FVA3-Ang1 and examined the transcriptome analysis. Priming for 1 h did not change whole gene expression profiles of PBSC, whereas priming for 24 h did change the pattern from myeloid toward endotheloid lineage. In mouse models of hind-limb ischemia and myocardial infarction, FVA3-Ang1-primed PBSCs showed superior engraftment and tissue regeneration compared to non-primed cells. A clinical trial is underway to assess efficacy and safety of FVA3-Ang1-primed PBSCs when infused via the culprit coronary artery following emergent stent implantation.

Background: Ulcerative colitis (UC) is a chronic inflammatory bowel disorder with increasing incidence globally. However, the understanding of UC pathogenesis remains limited.

Methods: DSS-induced UC mouse model and lipopolysaccharide (LPS)-treated colonic epithelial cell (CEC) model were established. The pathological changes in colons were evaluated by hematoxylin and eosin. Colon injury was graded by pathological scoring, evaluation of colon length and disease activity index. qRT-PCR, Western blot, immunofluorescent staining, and ELISA assay were used to detect the expression and secretion of key molecules. CCK-8 was employed to monitor cell viability. The m⁶A modification of phosphoglycerate dehydrogenase (PHGDH) was assessed by MeRIP assay, and the SUMOylation of PHGDH, as well as the association between PHGDH and ubiquitin conjugating enzyme 9 (UBC9), were detected by co-immunoprecipitation.

Results: PHGDH knockdown alleviated DSS-induced colitis in mice. Inhibiting PHGDH promoted autophagy and inhibited inflammation in DSS-induced colitis and LPS-treated CECs. Methyltransferase-like 3 (METTL3) mediated m⁶A modification of PHGDH in LPS-treated CECs. PHGDH overexpression reversed METTL3 knockdown-facilitated autophagy in the in vitro UC model. Additionally, UBC9-mediated SUMOylation regulated PHGDH protein stability in vitro. Enhanced SUMOylation of PHGDH rescued LPS-impaired cell viability via promoting autophagy. METTL3 inhibited autophagy in LPS-treated CECs by regulating UBC9/PHGDH axis. METTL3 knockdown and UBC9 overexpression synergistically alleviated DSS-induced colon injury. Furthermore, curcumin promoted autophagy via modulating METTL3/UBC9/PHGDH axis, thereby alleviating colonic damage in ulcerative colitis.

Conclusion: m⁶A modification and SUMOylation of PHGDH regulated UC through Beclin-1-dependent autophagy.

Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive lipid storage disease characterized by the accumulation of cholestanol. CTX patients often suffer from cognitive impairment. We found that serum cholestanol levels are higher in Alzheimer's disease (AD) patients than in control subjects. Thus, we tested whether cholestanol regulates the pathogenesis of AD. Cholestanol promotes tau fragmentation and hyperphosphorylation by activating asparagine endopeptidase (AEP). AEP knockdown alleviates cholestanol-induced tau fragmentation and phosphorylation. Feeding cholestanol to tau P301S mice aggravates tau pathology and behavioral defects, while knockout of AEP ameliorates cholestanol-induced tau pathology and behavioral defects in tau P301S mice. These results highlight the role of AEP-mediated tau cleavage in cholestanol-induced tau pathology and cognitive decline. The data also identify the potential therapeutic target of AEP in AD, particularly in AD patients with elevated serum cholestanol levels.