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Redox Biology Aug 2024Elevated lactate levels are a significant biomarker of sepsis and are positively associated with sepsis-related mortality. Sepsis-associated lung injury (ALI) is a...
Elevated lactate levels are a significant biomarker of sepsis and are positively associated with sepsis-related mortality. Sepsis-associated lung injury (ALI) is a leading cause of poor prognosis in clinical patients. However, the underlying mechanisms of lactate's involvement in sepsis-associated ALI remain unclear. In this study, we demonstrate that lactate regulates N6-methyladenosine (m6A) modification levels by facilitating p300-mediated H3K18la binding to the METTL3 promoter site. The METTL3-mediated m6A modification is enriched in ACSL4, and its mRNA stability is regulated through a YTHDC1-dependent pathway. Furthermore, short-term lactate stimulation upregulates ACSL4, which promotes mitochondria-associated ferroptosis. Inhibition of METTL3 through knockdown or targeted inhibition effectively suppresses septic hyper-lactate-induced ferroptosis in alveolar epithelial cells and mitigates lung injury in septic mice. Our findings suggest that lactate induces ferroptosis via the GPR81/H3K18la/METTL3/ACSL4 axis in alveolar epithelial cells during sepsis-associated ALI. These results reveal a histone lactylation-driven mechanism inducing ferroptosis through METTL3-mediated m6A modification. Targeting METTL3 represents a promising therapeutic strategy for patients with sepsis-associated ALI.
Topics: Ferroptosis; Methyltransferases; Animals; Sepsis; Mice; Humans; Coenzyme A Ligases; Adenosine; Lung Injury; Acute Lung Injury; Male; Disease Models, Animal; Lactic Acid
PubMed: 38852200
DOI: 10.1016/j.redox.2024.103194 -
Biology Direct Jun 2024The molecular mechanisms of osteosarcoma (OS) are complex. In this study, we focused on the functions of melanoma cell adhesion molecule (MCAM), methyltransferase 3...
BACKGROUND
The molecular mechanisms of osteosarcoma (OS) are complex. In this study, we focused on the functions of melanoma cell adhesion molecule (MCAM), methyltransferase 3 (METTL3) and insulin like growth factor 2 mRNA binding protein 1 (IGF2BP1) in OS development.
METHODS
qRT-PCR assay and western blot assay were performed to determine mRNA and protein expression of MCAM, METTL3, IGF2BP1 and YY1. MTT assay and colony formation assay were conducted to assess cell proliferation. Cell apoptosis, invasion and migration were evaluated by flow cytometry analysis, transwell assay and wound-healing assay, respectively. Methylated RNA Immunoprecipitation (MeRIP), dual-luciferase reporter, Co-IP, RIP and ChIP assays were performed to analyze the relationships of MCAM, METTL3, IGF2BP1 and YY1. The functions of METTL3 and MCAM in tumor growth were explored through in vivo experiments.
RESULTS
MCAM was upregulated in OS, and MCAM overexpression promoted OS cell growth, invasion and migration and inhibited apoptosis. METTL3 and IGF2BP1 were demonstrated to mediate the m6A methylation of MCAM. Functionally, METTL3 or IGF2BP1 silencing inhibited OS cell progression, while MCAM overexpression ameliorated the effects. Transcription factor YY1 promoted the transcription level of METTL3 and regulated METTL3 expression in OS cells. Additionally, METTL3 deficiency suppressed tumor growth in vivo, while MCAM overexpression abated the effect.
CONCLUSION
YY1/METTL3/IGF2BP1/MCAM axis aggravated OS development, which might provide novel therapy targets for OS.
Topics: Osteosarcoma; Methyltransferases; Humans; RNA-Binding Proteins; Adenosine; Cell Line, Tumor; Animals; Mice; Cell Proliferation; Bone Neoplasms; Disease Progression; Mice, Nude; Apoptosis; Cell Movement; Gene Expression Regulation, Neoplastic
PubMed: 38849910
DOI: 10.1186/s13062-024-00486-x -
Nature Communications Jun 2024N-methyladenosine (mA) plays critical roles in regulating mRNA metabolism. However, comprehensive mA methylomes in different plant tissues with single-base precision...
N-methyladenosine (mA) plays critical roles in regulating mRNA metabolism. However, comprehensive mA methylomes in different plant tissues with single-base precision have yet to be reported. Here, we present transcriptome-wide mA maps at single-base resolution in different tissues of rice and Arabidopsis using mA-SAC-seq. Our analysis uncovers a total of 205,691 mA sites distributed across 22,574 genes in rice, and 188,282 mA sites across 19,984 genes in Arabidopsis. The evolutionarily conserved mA sites in rice and Arabidopsis ortholog gene pairs are involved in controlling tissue development, photosynthesis and stress response. We observe an overall mRNA stabilization effect by 3' UTR mA sites in certain plant tissues. Like in mammals, a positive correlation between the mA level and the length of internal exons is also observed in plant mRNA, except for the last exon. Our data suggest an active mA deposition process occurring near the stop codon in plant mRNA. In addition, the MTA-installed plant mRNA mA sites correlate with both translation promotion and translation suppression, depicting a more complicated regulatory picture. Our results therefore provide in-depth resources for relating single-base resolution mA sites with functions in plants and uncover a suppression-activation model controlling mA biogenesis across species.
Topics: Oryza; Arabidopsis; Adenosine; Gene Expression Regulation, Plant; RNA, Messenger; Transcriptome; RNA, Plant; 3' Untranslated Regions; Gene Expression Profiling; RNA Stability; Exons; Codon, Terminator
PubMed: 38849358
DOI: 10.1038/s41467-024-48941-7 -
Virus Research Aug 2024The conversion of Adenosine (A) to Inosine (I), by Adenosine Deaminases Acting on RNA or ADARs, is an essential post-transcriptional modification that contributes to...
The conversion of Adenosine (A) to Inosine (I), by Adenosine Deaminases Acting on RNA or ADARs, is an essential post-transcriptional modification that contributes to proteome diversity and regulation in metazoans including humans. In addition to its transcriptome-regulating role, ADARs also play a major part in immune response to viral infection, where an interferon response activates interferon-stimulated genes, such as ADARp150, in turn dynamically regulating host-virus interactions. A previous report has shown that infection from reoviruses, despite strong activation of ADARp150, does not influence the editing of some of the major known editing targets, while likely editing others, suggesting a potentially nuanced editing pattern that may depend on different factors. However, the results were based on a handful of selected editing sites and did not cover the entire transcriptome. Thus, to determine whether and how reovirus infection specifically affects host ADAR editing patterns, we analyzed a publicly available deep-sequenced RNA-seq dataset, from murine fibroblasts infected with wild-type and mutant reovirus strains that allowed us to examine changes in editing patterns on a transcriptome-wide scale. To the best of our knowledge, this is the first transcriptome-wide report on host editing changes after reovirus infection. Our results demonstrate that reovirus infection induces unique nuanced editing changes in the host, including introducing sites uniquely edited in infected samples. Genes with edited sites are overrepresented in pathways related to immune regulation, cellular signaling, metabolism, and growth. Moreover, a shift in editing targets has also been observed, where the same genes are edited in infection and control conditions but at different sites, or where the editing rate is increased for some and decreased for other differential targets, supporting the hypothesis of dynamic and condition-specific editing by ADARs.
Topics: Animals; Mice; Fibroblasts; Transcriptome; RNA Editing; Inosine; Adenosine Deaminase; Adenosine; Reoviridae Infections; Host-Pathogen Interactions; RNA-Binding Proteins; Reoviridae
PubMed: 38848818
DOI: 10.1016/j.virusres.2024.199413 -
BMC Ophthalmology Jun 2024The purpose of this study was to investigate the photoprotection effect of peroxiredoxin 1 (PRDX1) protein in ultraviolet B (UVB) irradiation-induced damage of retinal...
BACKGROUND
The purpose of this study was to investigate the photoprotection effect of peroxiredoxin 1 (PRDX1) protein in ultraviolet B (UVB) irradiation-induced damage of retinal pigment epithelium (RPE) and its possible molecular mechanism.
METHODS
ARPE-19 cell viability and apoptosis were assessed by MTT assay and flow cytometry, respectively. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect the PRDX1 expression. The corresponding kits were employed to measure the levels or activities of lactate dehydrogenase (LDH), 8-hydroxy-2-deoxyguanosine (8-OHdG), reactive oxygen species (ROS), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD). Western blotting was applied to examine PRDX1 expression and mitogen-activated protein kinase (MAPK) signaling pathway-related proteins.
RESULTS
After exposure to 20 mJ/cm intensity of UVB irradiation for 24 h, ARPE-19 cells viability was decreased, the leakage degree of LDH and 8-OHdG were increased, and cell apoptosis was elevated. The expression of PRDX1 was significantly down-regulated in UVB-induced ARPE-19 cells. The low expression of PRDX1 was involved in high irradiation intensity. Overexpression of PRDX1 increased cell activity, decreased cell apoptosis, and LDH as well as 8-OHdG leakage in UVB-induced ARPE-19 cells. In addition to alleviating UVB-induced cell damage, PRDX1 overexpression also inhibited UVB-induced oxidative stress (down-regulation of ROS and MDA levels, up-regulation of GSH-Px and SOD activities) and the activation of MAPK signaling pathway in ARPE-19 cells.
CONCLUSION
PRDX1 exerts a photoprotection effect on RPE by attenuating UVB-induced cell damage and inhibiting oxidative stress, which can be attributed to the inhibition of MAPK signaling pathway activation.
Topics: Humans; Oxidative Stress; Retinal Pigment Epithelium; Peroxiredoxins; Ultraviolet Rays; Cell Survival; Apoptosis; Reactive Oxygen Species; MAP Kinase Signaling System; Cell Line; Blotting, Western; Cells, Cultured; 8-Hydroxy-2'-Deoxyguanosine; Signal Transduction
PubMed: 38844903
DOI: 10.1186/s12886-024-03489-4 -
Nature Communications Jun 2024Neuronal differentiation requires building a complex intracellular architecture, and therefore the coordinated regulation of defined sets of genes. RNA-binding proteins...
Neuronal differentiation requires building a complex intracellular architecture, and therefore the coordinated regulation of defined sets of genes. RNA-binding proteins (RBPs) play a key role in this regulation. However, while their action on individual mRNAs has been explored in depth, the mechanisms used to coordinate gene expression programs shaping neuronal morphology are poorly understood. To address this, we studied how the paradigmatic RBP IMP1 (IGF2BP1), an essential developmental factor, selects and regulates its RNA targets during the human neuronal differentiation. We perform a combination of system-wide and molecular analyses, revealing that IMP1 developmentally transitions to and directly regulates the expression of mRNAs encoding essential regulators of the microtubule network, a key component of neuronal morphology. Furthermore, we show that m6A methylation drives the selection of specific IMP1 mRNA targets and their protein expression during the developmental transition from neural precursors to neurons, providing a molecular principle for the onset of target selectivity.
Topics: Humans; RNA-Binding Proteins; Microtubules; Neurons; Cell Differentiation; RNA, Messenger; Methylation; Neurogenesis; Adenosine; Gene Expression Regulation, Developmental
PubMed: 38844464
DOI: 10.1038/s41467-024-49139-7 -
PLoS Pathogens Jun 2024Although lack of ADAR (adenosine deaminase acting on RNA) orthologs, genome-wide A-to-I editing occurs specifically during sexual reproduction in a number of filamentous... (Review)
Review
Although lack of ADAR (adenosine deaminase acting on RNA) orthologs, genome-wide A-to-I editing occurs specifically during sexual reproduction in a number of filamentous ascomycetes, including Fusarium graminearum and Neurospora crassa. Unlike ADAR-mediated editing in animals, fungal A-to-I editing has a strong preference for hairpin loops and U at -1 position, which leads to frequent editing of UAG and UAA stop codons. Majority of RNA editing events in fungi are in the coding region and cause amino acid changes. Some of these editing events have been experimentally characterized for providing heterozygote and adaptive advantages in F. graminearum. Recent studies showed that FgTad2 and FgTad3, 2 ADAT (adenosine deaminase acting on tRNA) enzymes that normally catalyze the editing of A34 in the anticodon of tRNA during vegetative growth mediate A-to-I mRNA editing during sexual reproduction. Stage specificity of RNA editing is conferred by stage-specific expression of short transcript isoforms of FgTAD2 and FgTAD3 as well as cofactors such as AME1 and FIP5 that facilitate the editing of mRNA in perithecia. Taken together, fungal A-to-I RNA editing during sexual reproduction is catalyzed by ADATs and it has the same sequence and structural preferences with editing of A34 in tRNA.
Topics: RNA Editing; Adenosine Deaminase; Fungal Proteins; Ascomycota; RNA, Fungal; Adenosine; Inosine; Fusarium; Neurospora crassa
PubMed: 38843141
DOI: 10.1371/journal.ppat.1012238 -
Biological & Pharmaceutical Bulletin 2024Motile cilia in the ependymal cells that line the brain ventricles play pivotal roles in cerebrospinal fluid (CSF) flow in well-defined directions. However, the...
Motile cilia in the ependymal cells that line the brain ventricles play pivotal roles in cerebrospinal fluid (CSF) flow in well-defined directions. However, the substances and pathways which regulate their beating have not been well studied. Here, we used primary cultured cells derived from neonatal mouse brain that possess motile cilia and found that adenosine (ADO) stimulates ciliary beating by increasing the ciliary beat frequency (CBF) in a concentration-dependent manner, with the ED value being 5 µM. Ciliary beating stimulated by ADO was inhibited by A receptor (AR) antagonist MRS1754 without any inhibition by antagonists of other ADO receptor subtypes. The expression of AR on the cilia was also confirmed by immunofluorescence. The values of CBF were also increased by forskolin, which is an activator of adenylate cyclase, whereas they were not further increased by the addition of ADO. Furthermore, ciliary beating was not stimulated by ADO in the presence of a protein kinase A (PKA) inhibitors. These results altogether suggest that ADO stimulates ciliary beating through AR on the cilia, and activation of PKA.
Topics: Animals; Cilia; Receptor, Adenosine A2B; Cyclic AMP-Dependent Protein Kinases; Adenosine; Brain; Mice; Animals, Newborn; Cells, Cultured; Signal Transduction; Adenosine A2 Receptor Antagonists; Colforsin; Ependyma
PubMed: 38839362
DOI: 10.1248/bpb.b23-00913 -
Turkish Journal of Ophthalmology Jun 2024To examine changes in tear oxidative stress levels and tear film functions in patients with blepharoptosis and dermatochalasis following conjunctiva-Müller muscle...
OBJECTIVES
To examine changes in tear oxidative stress levels and tear film functions in patients with blepharoptosis and dermatochalasis following conjunctiva-Müller muscle resection (CMMR) and blepharoplasty surgeries.
MATERIALS AND METHODS
This prospective study included 32 healthy controls and 62 patients with blepharoptosis or dermatochalasis. CMMR surgery was performed in 20 eyes and upper blepharoplasty was performed in 42 eyes. Tear oxidative stress markers (8-hydroxy-2’-deoxyguanosine [8-OHdG] and 4-hydroxy-2-nonenal [4-HNE]) were quantified by enzyme-linked immunosorbent assay and tear film functions were evaluated preoperatively and at 1 and 6 months postoperatively. The same assessments were performed in the control group at the same time points.
RESULTS
Preoperative tear 8-OHdG and 4-HNE levels were lower in healthy controls (52.8±13.5 ng/mL and 27.8±6.4 ng/mL, respectively) compared to patients with dermatochalasis (86.1±37.2 ng/mL and 29.8±11.1 ng/mL, respectively) and blepharoptosis (90.4±39.3 ng/mL and 43.1±4.2 ng/mL, respectively) (p<0.001). 8-OHdG levels were increased at 1 month after CMMR, while both markers were decreased 1 month postoperatively in the blepharoplasty group (p=0.034). Schirmer 1 and OSDI scores did not change throughout the visits in both patient groups, but a temporary decrease in tear break-up time (TBUT) was observed after CMMR (p=0.017).
CONCLUSION
Dermatochalasis and blepharoptosis were associated with higher tear oxidative stress levels. CMMR surgery caused a temporary decrease in TBUT scores and an increase in oxidative stress in the first postoperative month.
Topics: Humans; Oxidative Stress; Blepharoptosis; Female; Male; Prospective Studies; Tears; Blepharoplasty; Middle Aged; Conjunctiva; Oculomotor Muscles; 8-Hydroxy-2'-Deoxyguanosine; Adult; Biomarkers; Enzyme-Linked Immunosorbent Assay; Aged; Aldehydes
PubMed: 38836622
DOI: 10.4274/tjo.galenos.2024.02697 -
Cell Death & Disease Jun 2024Glioma is the most common and aggressive type of primary malignant brain tumor. The N6-methyladenosine (m6A) modification widely exists in eukaryotic cells and plays an...
Glioma is the most common and aggressive type of primary malignant brain tumor. The N6-methyladenosine (m6A) modification widely exists in eukaryotic cells and plays an important role in the occurrence and development of human tumors. However, the function and mechanism of heterogeneous nuclear ribonucleoprotein C (HNRNPC), an RNA-binding protein and m6A reader in gliomas remains to be comprehensively and extensively explored. Herein, we found that HNRNPC mRNA and protein overexpression were associated with a poor prognosis for patients with gliomas, based on the data from TCGA, the CGGA, and the TMAs. Biologically, HNRNPC knockdown markedly repressed malignant phenotypes of glioma in vitro and in vivo, whereas ectopic HNRNPC expression had the opposite effect. Integrative RNA sequencing and MeRIP sequencing analyses identified interleukin-1 receptor-associated kinase 1 (IRAK1) as a downstream target of HNRNPC. The glioma public datasets and tissue microarrays (TMAs) data indicated that IRAK1 overexpression was associated with poor prognosis, and IRAK1 knockdown significantly repressed malignant biological behavior in vitro. Mechanistically, HNRNPC maintains the mRNA stability of IRAK1 in an m6A-dependent manner, resulting in activation of the mitogen-activated protein kinase (MAPK) signaling pathway, which was necessary for the malignant behavior of glioma. Our findings demonstrate the HNRNPC-IRAK1-MAPK axis as a crucial carcinogenic factor for glioma and the novel underlying mechanism of IRAK1 upregulation, which provides a rationale for therapeutically targeting epitranscriptomic modulators in glioma.
Topics: Humans; Glioma; Interleukin-1 Receptor-Associated Kinases; RNA, Messenger; Disease Progression; Heterogeneous-Nuclear Ribonucleoprotein Group C; Cell Line, Tumor; MAP Kinase Signaling System; Mice; RNA Stability; Mice, Nude; Animals; Gene Expression Regulation, Neoplastic; Brain Neoplasms; Female; Male; Adenosine; Prognosis
PubMed: 38830885
DOI: 10.1038/s41419-024-06736-0