m6A Methylation Levels Research Articles

High-throughput Sequencing Reveals N6-methyladenosine-modified LncRNAs as Potential Biomarkers in Mice with Liver Fibrosis.

N6-methyladenosine (m6A) is the most frequent internal modification in eukaryotic RNA. Long noncoding RNAs (lncRNAs) are a new type of noncoding regulatory molecule with multiple cellular functions. Both are closely related to the occurrence and development of liver fibrosis (LF). However, the role of m6A-methylated lncRNAs in the progression of LF remains largely unknown. In this study, HE and Masson staining were used to observe pathological changes in the liver, m6A-modified RNA immunoprecipitation sequencing (m6A-seq) was performed to systematically evaluate the m6A modification level of lncRNAs in LF mice, meRIP-qPCR and RT-qPCR were used to detect the m6A methylation level and RNA expression level of the target lncRNAs. A total of 415 m6A peaks were detected in 313 lncRNAs in liver fibrosis tissues. There were 98 significantly different m6A peaks in LF, which were located on 84 lncRNAs, of which 45.2% of the lncRNA length was between 200-400 bp. At the same time, the first three chromosomes of these methylated lncRNAs were chromosomes 7, 5 and 1. RNA sequencing identified 154 differentially expressed lncRNAs in LF. The joint analysis of m6A-seq and RNA-seq found that there were three lncRNAs with significant changes in m6A methylation and RNA expression levels: lncRNA H19, lncRNA Gm16023 and lncRNA Gm17586. Subsequently, the verification results showed that the m6A methylation levels of lncRNA H19 and lncRNA Gm17586 were significantly increased, while that of lncRNA Gm16023 was significantly decreased, and the RNA expression of three lncRNAs was significantly decreased. Through the establishment of a lncRNA-miRNA-mRNA regulatory network, the possible regulatory relationships of lncRNA H19, lncRNA Gm16023 and lncRNA Gm17586 in LF were revealed. This study revealed the unique m6A methylation pattern of lncRNAs in LF mice, suggesting that the m6A methylation modification of lncRNAs is related to the occurrence and development of LF.

Transcriptome-wide N6-methyladenosine (m6A) profiling of compatible and incompatible responses reveals a nonhost resistance–specific m6A modification involved in soybean–soybean cyst nematode interaction

Soybean cyst nematode (SCN, Heterodera glycines) is a devastating pathogen that infects soybean (Glycine max L. Merrill) and disrupts soybean production worldwide. SCN infection upregulates or downregulates the expression of multiple genes in soybean. However, the regulatory mechanisms that underlie these changes in gene expression remain largely unexplored. N6-methyladenosine (m6A) methylation, one of the most prevalent mRNA modifications, contributes to transcriptional reprogramming during plant responses to pathogen infection. Nevertheless, the role of m6A methylation in establishing compatible and incompatible soybean responses to SCN has not previously been studied. Here, we performed transcriptome-wide m6A profiling of soybean roots infected with virulent and avirulent populations of SCN. Compared with the compatible response, the incompatible response was associated with higher global m6A methylation levels, as well as more differentially modified m6A peaks (DMPs) and differentially expressed genes (DEGs). A total of 133 and 194 genes showed significant differences in both expression and m6A methylation levels in compatible and incompatible interactions; the most significantly enriched gene ontology terms associated with these genes were plant–pathogen interaction (compatible) and folate biosynthesis (incompatible). Our findings demonstrate that the m6A methylation profiles of compatible and incompatible soybean responses are distinct and provide new insights into the regulatory mechanism underlying soybean response to SCN at the post-transcriptional modification level, which will be valuable for improving the SCN resistance breeding.

N6-Methyladenosine (m6A) Methylation Is Associated with the Immune Microenvironments in Acute Intracerebral Hemorrhage (ICH).

Researchers have recently found that N6-methyladenosine (m6A) is a type of internal posttranscriptional modification that is essential in mammalian mRNA. However, the features of m6A RNA methylation in acute intracerebral hemorrhage (ICH) remain unknown. To explore differential methylations and to discover their functions in acute ICH patients, we recruited three acute ICH patients, three healthy controls, and an additional three patients and healthy controls for validation. The m6A methylation levels in blood samples from the two groups were determined by ultrahigh-performance liquid chromatography coupled with triple quadruple mass spectrometry (UPLC-QQQ-MS). Methylated RNA immunoprecipitation sequencing (MeRIP-seq) was employed to identify differences in m6A modification, and the differentially expressed m6A-modified genes were confirmed by MeRIP-qPCR. We found no significant differences in the total m6A levels between the two groups but observed differential methylation peaks. Compared with the control group, the coding genes showing increased methylation following acute ICH were mostly involved in processes connected with osteoclast differentiation, the neurotrophin signaling pathway, and the spliceosome, whereas genes with reduced m6A modification levels after acute ICH were found to be involved in the B-cell and T-cell receptor signaling pathways. These results reveal that differentially m6A-modified genes may influence the immune microenvironments in acute ICH.

The Role and Mechanism of Ferroptosis Mediated by METTL3-m6A Modification in Regulating Radioresistance of Esophageal Cancer

Radioresistance remains the major cause of recurrence within two years after radical radiotherapy in approximately 50% of patients with esophageal cancer (ESCC). Recently, it has been reported that enhancing ferroptosis can reverse tumor radioresistance. However, the underlying mechanisms remain elusive. The aim of this study was to elucidate the role and mechanism of ferroptosis mediated by METTL3 N6-methyladenosine (m6A) modification in regulating radioresistance of Esophageal Cancer. We hypothesize that inhibition of ferroptosis confers radioresistance in Esophageal Cancer by METTL3-induced m6A modification which increase the expression of m6A in the 3'UTR region of SOCS6 and inhibits its expression. To explore the relationship between radioresistance and ferroptosis. Firstly, ferroptosis was analyzed by 4-HNE staining in ESCC specimens; Furthermore, cell death was detected by propidium iodide (PI) or SYTOX Green staining combined with microscopy or flow cytometry in ESCC radioresistance cells and parental cells, and Iron Assay Kit,C11-BODIPY were used to examine whether ferroptosis were inhibited in radioresistance cells. Subsequently, MeRIP-seq and MeRIP-PCR were performed for discussing the relationship between ferroptosis and m6A. Finally, Mettl3 depleted cells were generated with CRISPR/Cas9-mediated knockout system. Then, m6A methylation level, sensitivity to radiation and ferroptosis of Mettl3 depleted cells by EpiQuik m6A RNA methylation quantification kit, colony formation, C11-BODIPY and Western Blot. Firstly, we found that the level of lipid peroxide 4-HNE in ESCC samples that recurred after radical radiotherapy was significantly lower than that in radiotherapy (40Gy), and the ferroptosis of radioresistance cells was inhibited. MeRIP-seq found that the level of m6A in radioresistance cells increased significantly, and then the KEGG pathway analysis of MeRIP-seq results showed that hypermethylation of m6A was closely related to ferroptosis signal pathway. and we also found that the level of m6A was significantly decreased by adding agonist (Erastin), whereas the modification level was significantly increased by adding inhibitor Fer-1. Meanwhile, we found that the level of m6A was significantly decreased in radioresistance cells silencing METTL3, while the ferroptosis was activated, which caused the radiosensitivity of ESCC. Lastly, MeRIP-PCR data showed that METTLT3 induced a significant increase in m6A level in 3' UTR region of SOCS6 mRNA and inhibited its expression, which eventually led to radioresistance of ESCC. m6A-regulated ferroptosis inhibition confers radioresistance of ESCC. METTL3 up-regulated m6A in SOCS6 3' UTR and inhibited the expression of SOCS6, which caused the inhibition of ferroptosis.

The m6A reader YTHDC1-mediated lncRNA CTBP1-AS2 m6A modification accelerates cholangiocarcinoma progression

BackgroundCholangiocarcinoma (CCA) is a serious malignancy originating from the bile ducts and the second most common primary liver cancer. Long non-coding RNA (lncRNA) is a functional lncRNA that plays an important role in human cancers. However, the role and underlying mechanisms of CTBP1-AS2 in CCA remain unknown. PurposeIn this study, we investigated the functional role and mechanism of long-stranded non-coding RNA (lncRNA) C-terminal binding protein 1 antisense RNA 2 (CTBP1-AS2) in CCA progression. ResultIn the present study, the bioinformatics analysis revealed that YTHDC1 and CTBP1-AS2 were significantly upregulated, and it was confirmed in cholangiocarcinoma tissues from CCA patients. Meanwhile, we demonstrated that knockdown of YTHDC1 or lncRNA CTBP1-AS2 inhibited CCA cell proliferation, migration and invasion, blocked the cell cycle in G2/M phase and promoted apoptosis of CCA cells. In addition, lncRNA CTBP1-AS2-mediated N6-methyladenosine (m6A) methylation levels were significantly elevated in cholangiocarcinoma tissues, whereas knockdown of YTHDC1 resulted in a significant down-regulation of m6A methylation levels by lncRNA CTBP1-AS2. ConclusionOur results suggest that YTHDC1 affects cholangiocarcinoma progression by modifying the lncRNA CTBP1-AS2 m6A, and CTBP1-AS2 may be a promising therapeutic target for CCA.

HIF-1α-induced upregulation of m6A reader IGF2BP1 facilitates peripheral nerve injury recovery by enhancing SLC7A11 mRNA stabilization.

The recovery of peripheral nerve injury (PNI) is not ideal in clinic. Our previous study revealed that hypoxia treatment promoted PNI repair by inhibiting ferroptosis. The aim of this study was to investigate the underlying molecular mechanism of HIF-1α in hypoxia-PNI recovery. M6A dot blot was used to determine the total level of m6A modification. Besides, HIF-1α small interfering RNA (siRNA) or IGF2BP1 overexpression vector was transfected into dorsal root ganglion (DRG) neurons to alter the expression of HIF-1α and IGF2BP1. Subsequently, MeRIP-PCR analysis was applied to validate the m6A methylation level of SLC7A11. We demonstrated the hypoxia stimulated HIF-1α-dependent expression of IGF2BP1 and promoted the overall m6A methylation levels of DRG neurons. Overexpression of HIF-1α increased the expressions of neurotrophic factors including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and glial-derived neurotrophic factor (GDNF), which could be effectively reversed by siRNA knockdown of IGF2BP1. Moreover, upregulation of HIF-1α contributed to the m6A methylation level and mRNA stabilization of SLC7A11. This study revealed that the HIF-1α/IGF2BP1/SLC7A11 regulatory axis facilitated the recovery of injured DRG neurons. Our findings suggest a novel insight for the m6A methylation modification in PNI recovery.

Pan-cancer analysis and experimental validation revealed the m6A methyltransferase KIAA1429 as a potential biomarker for diagnosis, prognosis, and immunotherapy.

KIAA1429, also known as VIRMA (vir-like m6A methyltransferase associated), plays a crucial role in tumorigenesis by modulating the level of m6A methylation. Previous studies have reported the prevalent overexpression of KIAA1429 in multiple cancers, related to a poor prognosis. Nevertheless, the precise role of KIAA1429 in tumor progression and its impact on the immune response remains unclear. A differential analysis of KIAA1429 expression was performed across cancers using data from the Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases. We evaluated the role of KIAA1429 in the diagnosis, prognosis, and immunotherapy of tumor patients using bioinformatics methods. In addition, we also analyzed the associations between KIAA1429 and DNA methylation, immunotherapy. RT-qPCR was used to study the expression levels of KIAA1429 mRNA in 11 cell lines. KIAA1429 is found to be overexpressed in 28 cancer types, but its expression is relatively low in patients with acute myeloid leukemia (LAML) and ovarian serous cystadenocarcinoma (OV). Moreover, KIAA1429 demonstrates a positive correlation with advanced stages of multiple cancers. Kaplan-Meier (KM) analysis suggested that patients with elevated KIAA1429 expression had shorter survival. Furthermore, KIAA1429 shows strong associations with DNA methylation, tumor-infiltrating immune cells (TIICs), and the tumor microenvironment (TME). RT-qPCR results indicated significantly higher expression of KIAA1429 in tumor cells compared to matched-normal cells. In summary, our work illustrates that KIAA1429 expression is positively connected with poor prognosis in multiple cancers. Moreover, KIAA1429 could serve as a diagnostic factor and a predictor of immune response for specific tumor types.

Focused ultrasound combined with miR-1208-equipped exosomes inhibits malignant progression of glioma.

Exosomes (Exos) can safely and effectively deliver therapeutic substances to glioma cells; however, their blood-brain barrier (BBB) crossing capacity remains limited. Focused ultrasound (FUS) can transiently, reversibly, and locally open the BBB, while the effects of FUS combined with Exos-miRNA on the treatment of glioma have not been explored to date. Exos were extracted by differential centrifugation and the efficacy of miR-1208-loaded Exos combined with FUS in the treatment of glioma was detected by CCK-8, colony formation, flow cytometry, transwell and tumour xenografts assays. The METTL3-mediated regulation of IGF2BP2 on mRNA stability of NUP214 was determined by MeRIP-qPCR, half-life and RIP assays. We used Exos secreted by mesenchymal stem cells as carriers for the tumour suppressor gene miR-1208, and following FUS irradiation, more Exos carrying miR-1208 were allowed to pass through the BBB, and the uptake of miR-1208 in Exos by glioma cells was promoted, thereby achieving high-efficiency tumour-suppressive effects. Furthermore, the molecular mechanism underlying this effect was elucidated that miR-1208 downregulated the m6A methylation level of NUP214 mRNA by negatively regulating the expression of METTL3, thereby NUP214 expression and TGF-β pathway activity were suppressed. MiR-1208-loaded Exos combined with FUS is expected to become an effective glioma treatment and deserves further clinical evaluation.

Molecular Mechanism of m6A Methylation Modification Genes METTL3 and FTO in Regulating Heat Stress in Sheep.

Heat stress is an important environmental factor affecting livestock production worldwide. Primary hepatocytes and preadipocytes derived from Hu sheep were used to establish a heat stress model. Quantitative reverse transcriptase-PCR (qRT-PCR) analysis showed that heat induction significantly increased the expression levels of heat stress protein (HSP) genes and the N6-methyladenosine (m6A) methylation modification genes: methyltransferase-like protein 3 (METTL3), methyltransferase-like protein 14 (METTL14), and fat mass and obesity associated protein (FTO). Heat stress simultaneously promoted cell apoptosis. Transcriptome sequencing identified 3980 upregulated genes and 2420 downregulated genes related to heat stress. A pathway enrichment analysis of these genes revealed significant enrichment in fatty acid biosynthesis, degradation, and the PI3K-Akt and peroxisome proliferator-activated receptor (PPAR) signaling pathways. Overexpression of METTL3 in primary hepatocytes led to significant downregulation of HSP60, HSP70, and HSP110, and significantly increased mRNA m6A methylation; FTO interference generated the opposite results. Primary adipocytes showed similar results. Transcriptome analysis of cells under METTL3 (or FTO) inference and overexpression revealed differentially expressed genes enriched in the mitogen-activated protein kinase (MAPK) signaling pathways, as well as the PI3K-Akt and Ras signaling pathways. We speculate that METTL3 may increase the level of m6A methylation to inhibit fat deposition and/or inhibit the expression of HSP genes to enhance the body's resistance to heat stress, while the FTO gene generated the opposite molecular mechanism. This study provides a scientific basis and theoretical support for sheep feeding and management practices during heat stress.

PARP1 modulates METTL3 promoter chromatin accessibility and associated LPAR5 RNA m6A methylation to control cancer cell radiosensitivity

Chromatin remodeling and N6-methyladenosine (m6A) modification are two critical layers in controlling gene expressionand DNA damage signaling in most eukaryotic bioprocesses. Here, we report that poly(ADP-ribose) polymerase 1 (PARP1) controls the chromatin accessibility of METTL3 to regulate its transcription and subsequent m6A methylation of poly(A)+ RNA in response to DNA damage induced by radiation. The transcription factors nuclear factor I-C (NFIC) and TATA binding protein (TBP) are dependent on PARP1 to access the METTL3 promoter to activate METTL3 transcription. Upon irradiation or PARP1 inhibitor treatment, PARP1 disassociated from METTL3 promoter chromatin, which resulted in attenuated accessibility of NFIC and TBP and, consequently, suppressed METTL3 expression and RNA m6A methylation. Lysophosphatidic Acid Receptor 5(LPAR5) mRNA was identified as a target of METTL3, and m6A methylation was located at A1881. The level of m6A methylation of LPAR5 significantly decreased, along with METTL3 depression, in cells after irradiation or PARP1 inhibition. Mutation of the LPAR5 A1881 locus in its 3' UTR results in loss of m6A methylation and, consequently, decreased stability of LPAR5 mRNA. METTL3-targeted small-molecule inhibitors depress murine xenograft tumor growth and exhibit a synergistic effect with radiotherapy invivo. These findings advance our comprehensive understanding of PARP-related biological roles, which may have implications for developing valuable therapeutic strategies for PARP1 inhibitors in oncology.

Dysregulation of TMEM16A impairs oviductal transport of embryos.

Ectopic pregnancy is an acute abdominalgia in obstetrics and gynecology, especially in fallopian tubal pregnancy. The ion channel protein transmembrane protein 16A (TMEM16A) is widely distributed in various tissues, even in the oviduct. In this study, we showed that TMEM16A was expressed in the human fallopian tube and was upregulated in patients with tubal pregnancy. By measuring isolated fallopian tube tissues, we found that TMEM16A was involved in regulating not only the contraction of muscle strips but also the beat frequency of cilia. In addition, pharmacological activation or inhibition of TMEM16A could lead to retention of embryos in oviducts. Moreover, the embryos in oviducts were delayed in development and some of them had malformations and deletions. The total number of embryos in the oviducts and uterus was significantly less than that of the control group. Furthermore, we detected changes in the level of m6A methylation, where the relevant writers and readers were reduced in tubal tissues from tubal pregnancies. In m6A mRNA methylation, writers catalyze the addition of methyl groups to cytosine residues and readers bind to the methyl groups and affect gene translation. In human fallopian tube epithelial cell line FTE187, we found that interference with methyltransferase 3 (METTL3) expression increased TMEM16A, suggesting that TMEM16A might be regulated by m6A methylation. In general, our study revealed a novel regulatory point for embryo transport and development, introducing a new role for the diagnosis and treatment of tubal pregnancy.NEW & NOTEWORTHY The ion channel protein TMEM16A is expressed in the epithelium and smooth muscle of the human fallopian tube and is upregulated in patients with tubal pregnancy. TMEM16A is involved in regulating the smooth muscle contraction and the cilia beating. Dysregulated TMEM16A may result in embryo retention in the oviduct and delayed early embryo development. Our study reveals a new regulatory point for embryo transport and development.

N6-methyladenosine hypomethylation of circGPATCH2L regulates DNA damage and apoptosis through TRIM28 in intervertebral disc degeneration.

Circular RNAs (circRNAs) are a class of noncoding RNAs that have been found to be involved in intervertebral disc degeneration (IVDD) progression, and N6-methyladenosine (m6A) broadly exists in circRNAs. Here, we identified circGPATCH2L with a low m6A methylation level to be upregulated in degenerative nucleus pulposus tissues. Mechanistically, as a protein decoy for tripartite motif containing 28 (TRIM28) within aa 402-452 region, circGPATCH2L abrogates the phosphorylation of TRIM28 and inhibits P53 degradation, which contributes to DNA damage accumulation and cellular apoptosis and leads to IVDD progression. Moreover, m6A-methylated circGPATCH2L is recognised and endoribonucleolytically cleaved by a YTHDF2-RPL10-RNase P/MRP complex to maintain the physiological state of nucleus pulposus cells. Thus, our data show the physiological significance of m6A modification in regulating circRNA abundance and provide a potentially effective therapeutic target for the treatment of IVDD.

Dynamic N6-methyladenosine RNA methylation landscapes reveal epi-transcriptomic modulation induced by ammonia nitrogen exposure in the Pacific whiteleg shrimp Litopenaeus vannamei

Despite the versatility of RNA m6A methylation in regulating various biological processes, its involvement in the physiological response to ammonia nitrogen toxicity in decapod crustaceans like shrimp remains enigmatic. Here, we provided the first characterization of dynamic RNA m6A methylation landscapes induced by toxic ammonia exposure in the Pacific whiteleg shrimp Litopenaeus vannamei. The global m6A methylation level showed significant decrease following ammonia exposure, and most of the m6A methyltransferases and m6A binding proteins were significantly repressed. Distinct from many well-studied model organisms, m6A methylated peaks in the transcriptome of L. vannamei were enriched not only near the termination codon and in the 3′ untranslated region (UTR), but also around the start codon and in the 5′ UTR. Upon ammonia exposure, 11,430 m6A peaks corresponding to 6113 genes were hypo-methylated, and 5660 m6A peaks from 3912 genes were hyper-methylated. The differentially methylated genes showing significant changes in expression were over-represented by genes associated with metabolism, cellular immune defense and apoptotic signaling pathways. Notably, the m6A-modified ammonia-responsive genes encompassed a subset of genes related to glutamine synthesis, purine conversion and urea production, implying that m6A methylation may modulate shrimp ammonia stress responses partly through these ammonia metabolic processes.

N6-methyladenosine profiling reveals that Xuefu Zhuyu decoction upregulates METTL14 and BDNF in a rat model of traumatic brain injury

Ethnopharmacological relevanceThe traditional Chinese herbal formula Xuefu Zhuyu decoction (XFZYD) is a classic formula in the category of invigorating blood circulation and resolving blood stasis. It has been proven to improve the neurological and ethological prognosis of traumatic brain injury. XFZYD promotes synaptic and axonal regeneration after traumatic brain injury, which is functionally modulated by the N6-methyladenosine (m6A) modification of RNA. However, the epigenetic effects of XFZYD on m6A modification remain unknown. Aim of the studyTo explore how XFZYD protects against traumatic brain injury induced by controlled cortical impact (CCI) injury by altering RNA m6A modification. Materials and methodsThe modified neurological severity scoring and Morris water maze were performed to evaluate the neuroprotective effects of XFZYD for 14 days and screen the dose. Then, dot blot, western blotting, and methylated RNA immunoprecipitation sequencing (MeRIP-Seq) were used to explore changes in RNA m6A modification in the perilesional cortex. The Metascape platform was used to analyze the Gene Ontology, Kyoto Encyclopedia of Genes and Genomes (KEGG), and Reactome pathway of the differential m6A-tagged genes. Furthermore, MeRIP-qPCR was conducted to quantify differences in the hub differential m6A modification gene brain-derived neurotrophic factor (Bdnf). ResultsXFZYD significantly ameliorated the neurological deficits, spatial learning, and memory impairments in rats post-CCI on day 14. XFZYD enhanced the m6A level, and the expression of METTL14 and YTHDC2 in the perilesional cortex of CCI rats. In all three groups, the 3'-untranslated regions and coding sequence were primarily enriched for m6A peaks. XFZYD reversed the increased proportion of 3'-untranslated regions, and the decreased proportion of coding sequence and 5'-untranslated regions post-CCI. Moreover, XFZYD markedly downregulated 41 elevated m6A-tagged transcripts and upregulated 119 decreased m6A-tagged transcripts following CCI. Gene ontology and KEGG pathway analysis revealed that XFZYD-regulated m6A-tagged transcripts were predominantly enriched in synapse assembly, synaptic plasticity, learning or memory, and MAPK signaling pathway. Then, the hub-regulated m6A-tagged gene BDNF was identified. Both the m6A methylation level and the protein level of BDNF were ascended by XFZYD treatment. ConclusionXFZYD improves neurological deficits, spatial learning and memory impairments in rats post-TBI probably through increasing the expression of METTL14 and BDNF in the cortex. Our study highlights a novel post-transcriptional regulation mechanism mediated by herbal medicine for traumatic brain injury treatment.

Transcriptome-wide m6A methylation in natural yellow leaf of Catalpa fargesii.

N6-methyladenosine (m6A) is the most abundant internal modification in eukaryotic messenger RNA, and involved in various biological processes in plants. However, the distribution features and functions of mRNA m6A methylation have been poorly explored in woody perennial plants. In this study, a new natural variety with yellow-green leaves, named Maiyuanjinqiu, was screened from the seedlings of Catalpa fargesii. Based on the preliminary experiment, the m6A methylation levels in the leaves of Maiyuanjinqiu were significantly higher than those in C. fargesii. Furthermore, a parallel analysis of m6A-seq and RNA-seq was carried out in different leaf color sectors. The result showed that m6A modification were mostly identified around the 3'-untranslated regions (3'-UTR), which was slightly negatively correlated with the mRNA abundance. KEGG and GO analyses showed that m6A methylation genes were associated with photosynthesis, pigments biosynthesis and metabolism, oxidation-reduction and response to stress, etc. The overall increase of m6A methylation levels in yellow-green leaves might be associated with the decreased the expression of RNA demethylase gene CfALKBH5. The silencing of CfALKBH5 caused a chlorotic phenotype and increased m6A methylation level, which further confirmed our hypothesis. Our results suggested that mRNA m6A methylation could be considered as a vital epigenomic mark and contribute to the natural variations in plants.

Fufang Zhenzhu Tiaozhi (FTZ) capsule ameliorates diabetes-accelerated atherosclerosis via suppressing YTHDF2-mediated m6A modification of SIRT3 mRNA

Ethnopharmacological relevanceFufang Zhenzhu TiaoZhi (FTZ), a Chinese medicinal decoction, has continuously been used to treat metabolic syndrome. Atherosclerosis is the main pathological basis of cardiovascular disease. The N6 methyladenosine (m6A) modification is a highly dynamic and reversible process involving a variety of important biological processes. Aim of the studyHere, we investigated the therapeutic effects and mechanism of FTZ in diabetes-accelerated atherosclerosis. Materials and methodsDoppler ultrasonography was used to examine the carotid intima-media thickness and plaque area in diabetic atherosclerosis patients. HFD mice were injected with streptozotocin to induce diabetes. HE and Oil red O staining were used to assess the effect of FTZ on lipid deposition. HUVECs were induced with HG/ox-LDL as a model of diabetic atherosclerosis. Furthermore, application of m6A methylation level kit, qRT-PCR, Western blot, tunel staining, reactive oxygen species staining and mPTP staining were performed to analyze the detailed mechanism. ResultsClinical trials of FTZ have shown obvious effect of lowering blood glucose and blood lipids. These effects were reversed after FTZ intervention. Compared with the control, lipid deposition decreased significantly after FTZ administration. FTZ reduced endothelial cell apoptosis. At the same time, we found that FTZ reversed the increase of methylation reader YTHDF2 caused by ox-LDL treatment. Subsequently, we discovered that YTHDF2 degraded SIRT3 mRNA, leading to endothelial cell apoptosis and oxidative stress. ConclusionFTZ attenuated diabetes-accelerated atherosclerosis by decreasing blood glucose and serum lipids levels, and increased endothelial cell antioxidant capacity, inhibited endothelial cell apoptosis via inhibiting YTHDF2-mediated m6A modification of SIRT3 mRNA, which reduced mRNA degradation.

Mechanistic exploration on neurodevelopmental toxicity induced by upregulation of alkbh5 targeted by triclosan exposure to larval zebrafish

Because triclosan (TCS) has been confirmed to cause severe neurotoxicity, it is urgent to disclose the underlying toxicity mechanisms at varying levels. TCS exposure resulted in a series of malformations in larval zebrafish, including reduced neurons, blood-vessel ablation and abnormal neurobehavior. Apoptosis staining and the upregulated expression of proapoptotic genes demonstrated that TCS induced neuronal apoptosis and neurotransmitter disorders. By integrating RT-qPCR analysis with the effects of pathway inhibitors and agonists, we found that TCS triggered abnormal regulation of neuron development-related functional genes, and suppressed the BDNF/TrkB signaling pathway. TCS inhibited total m6A-RNA modification level by activating the demethylase ALKBH5, and induced neurodevelopmental toxicity based on the knockdown experiments of alkbh5 and molecular docking. The main novelties of this study lies in: (1) based on specific staining and transgenic lines, the differential neurotoxicity effects of TCS were unravelled at individual, physiological, biochemical and molecular levels in vivo; (2) from a epigenetics viewpoint, the decreasing m6A methylation level was confirmed to be mediated by alkbh5 upregulation; and (3) both homology modeling and molecular docking evidenced the targeting action of TCS on ALKBH5 enzyme. These findings open a novel avene for TCS’s risk assessment and early intervention of the contaminant-sourcing diseases.

In vitro study of piwi interaction RNA-31106 promoting breast carcinogenesis by regulating METTL3-mediated m6A RNA methylation.

Breast cancer is the most common gynecological malignancy and the leading cause of cancer-related deaths in women. P-element induced wimpy testis (PIWI)-interacting RNAs (piRNAs) are novel non-coding RNAs whose abnormal expressions have been closely associated with multiple cancers. This study explored the roles and possible mechanisms of piRNA-31106 in breast cancer. The expression of piRNA-31106 in breast cancer tissues and cells was detected by reverse transcription polymerase chain reaction (RT-PCR). The pcDNA vector containing piRNA-31106 (pcDNA-piRNA-31106) and a short hairpin (sh)RNA containing piRNA-31106 (shRNA-piRNA-31106) were used to interfere with piRNA-31106 expression in breast cancer cells. The effects on cell proliferation, apoptosis/cell cycle, invasion, and metastasis were detected via Cell Counting Kit-8 (CCK-8), flow cytometry, transwell assays, and scratch tests, respectively. The protein expressions of murine double minute 2 (MDM2), cyclin-dependent kinase 4 (CDK4), and cyclinD1 were detected by Western blot analysis. The N6-methyladenosine (m6A) RNA methylation level and the binding relationship between piRNA-31106 and METTL3 were analyzed. The role of METTL3 in the regulation of breast cancer by piRNA-31106 was further analyzed by using small interfering (si)RNA targeting METTL3. PiRNA-31106 was highly expressed in breast cancer tissues and cell lines MDA-MB-231 and MCF-7. Overexpression of piRNA-31106 promoted the viability, invasion, and migration of breast cancer, inhibited apoptosis, and promoted the expressions of MDM2, CDK4, and cyclinD1. Inhibition of piRNA-31106 showed the opposite effect. In addition, piRNA-31106 promoted the m6A methylation levels and facilitated methyltransferase-like 3 (METTL3) expression in MDA-MB-231 and MCF-7 cells. RNA immunoprecipitation (RIP) assays confirmed the binding relationship between piRNA-31106 and METTL3. Further experiments demonstrated that si-METTL3 could inhibit the regulatory effects of piRNA-31106 on breast cancer. PiRNA-31106 was significantly highly expressed in breast cancer and could promote breast cancer progression by regulating METTL3-mediated m6A RNA methylation.

Short-chain fatty acid-butyric acid ameliorates granulosa cells inflammation through regulating METTL3-mediated N6-methyladenosine modification of FOSL2 in polycystic ovarian syndrome

Polycystic ovary syndrome (PCOS) is an endocrine and metabolic disorder characterized by chronic low-grade inflammation. Previous studies have demonstrated that the gut microbiome can affect the host tissue cells’ mRNA N6-methyladenosine (m6A) modifications. This study aimed to understand the role of intestinal flora in ovarian cells inflammation by regulating mRNA m6A modification particularly the inflammatory state in PCOS. The gut microbiome composition of PCOS and Control groups was analyzed by 16S rRNA sequencing, and the short chain fatty acids were detected in patients’ serum by mass spectrometry methods. The level of butyric acid was found to be decreased in the serum of the obese PCOS group (FAT) compared to other groups, and this was correlated with increased Streptococcaceae and decreased Rikenellaceae based on the Spearman’s rank test. Additionally, we identified FOSL2 as a potential METTL3 target using RNA-seq and MeRIP-seq methodologies. Cellular experiments demonstrated that the addition of butyric acid led to a decrease in FOSL2 m6A methylation levels and mRNA expression by suppressing the expression of METTL3, an m6A methyltransferase. Additionally, NLRP3 protein expression and the expression of inflammatory cytokines (IL-6 and TNF-α) were downregulated in KGN cells. Butyric acid supplementation in obese PCOS mice improved ovarian function and decreased the expression of local inflammatory factors in the ovary. Taken together, the correlation between the gut microbiome and PCOS may unveil crucial mechanisms for the role of specific gut microbiota in the pathogenesis of PCOS. Furthermore, butyric acid may present new prospects for future PCOS treatments.

M6A-dependent mevalonate kinase in juvenile hormone synthesis pathway regulates the diapause process of bivoltine silkworm (Bombyx mori).

Research has shown that epigenetic modification are involved the regulation of diapause in bivoltine silkworms (Bombyx mori), but it remains unclear how epigenetic modification in response to environmental signals precisely to regulate the diapause processing of bivoltine B. mori. In this study, the diapause terminated eggs of bivoltine B. mori, Qiufeng (QF) were divided into two groups: a QFHT group incubated at 25°C with a natural day/night cycle to produce diapause eggs, and a QFLT group incubated at 16.5°C in darkness to produce non-diapause eggs. On the 3rd day of the pupal stage, the total RNAs of the eggs were extracted and their N6-adenosine methylation (m6A) abundances were analyzed to explore the effects of m6A methylation on diapause in the silkworm. The results showed that 1984 m6A peaks are shared, 1563 in QFLT and 659 in QFHT. The m6A methylation level of the QFLT group was higher than that of the QFHT one in various signaling pathways. The m6A methylation rate of mevalonate kinase (MK) in the insect hormone synthesis pathway was significantly different between the two groups. The knockdown of MK by RNA interference in the pupae of QFLT resulted in females laying diapause eggs rather than non-diapause eggs after mating. m6A methylation involves in the diapause regulation of bivoltine B. mori by changing the expression levels of MK. This result provides a clearer image of the environmental signals on the regulation of diapause in bivoltine silkworms.