bims-rimeca 2023-02-12 papers

bims-rimeca

Biomed News

on RNA methylation in cancer

Issue of 2023–02–12
25 papers selected by
Sk Ramiz Islam, Saha Institute of Nuclear Physics

The m6A demethylase FTO promotes keloid formation by up-regulating COL1A1.
METTL3 stabilization by PIN1 promotes breast tumorigenesis via enhanced m6A-dependent translation.
METTL3 depletion contributes to tumour progression and drug resistance via N6 methyladenosine-dependent mechanism in HR+HER2-breast cancer.
Methyltransferase-like 3 aggravates endoplasmic reticulum stress in preeclampsia by targeting TMBIM6 in YTHDF2-dependent manner.
N6-methyladenosine modulation classes and immune microenvironment regulation in ischemic stroke.
N6-methyladenosine Modification of Hepatitis B Virus RNA in the Coding Region of HBx.
F-Box Protein 43, Stabilized by N6-Methyladenosine Methylation, Enhances Hepatocellular Carcinoma Cell Growth and Invasion via Promoting p53 Degradation in a Ubiquitin Conjugating Enzyme E2 C-Dependent Manner.
RBM3 suppresses stemness remodeling of prostate cancer in bone microenvironment by modulating N6-methyladenosine on CTNNB1 mRNA.
m6A-ELISA, a simple method for quantifying N6-methyladenosine from mRNA populations.
O-GlcNAcylation of YTHDF2 promotes HBV-related hepatocellular carcinoma progression in an N6-methyladenosine-dependent manner.
Overexpressed ZC3H13 suppresses papillary thyroid carcinoma growth through m6A modification-mediated IQGAP1 degradation.
METTL3 inhibits autoreactive Th17 cell responses in experimental autoimmune uveitis via stabilizing ASH1L mRNA.
Metal Exposure Promotes Colorectal Tumorigenesis via the Aberrant N6-Methyladenosine Modification of ATP13A3.
Metformin attenuates multiple myeloma cell proliferation and encourages apoptosis by suppressing METTL3-mediated m6A methylation of THRAP3, RBM25, and USP4.
m6A Modification Mediates Endothelial Cell Responses to Oxidative Stress in Vascular Aging Induced by Low Fluid Shear Stress.
FTO negatively regulates the cytotoxic activity of natural killer cells.
Role of NAT10-mediated ac4C-modified HSP90AA1 RNA acetylation in ER stress-mediated metastasis and lenvatinib resistance in hepatocellular carcinoma.
m6A-related lncRNA-based immune infiltration characteristic analysis and prognostic model for colonic adenocarcinoma.
Fragile X-Related Protein FXR1 Controls Human Adenovirus Capsid mRNA Metabolism.
RNA modification writers pattern in relation to tumor microenvironment and prognosis in prostate cancer.
Current Insights into m6A RNA Methylation and Its Emerging Role in Plant Circadian Clock.
Multi-omics analysis of N6-methyladenosine reader IGF2BP3 as a promising biomarker in pan-cancer.
Heterogeneous Nuclear Protein U Degraded the m6A Methylated TRAF3 Transcript by YTHDF2 To Promote Porcine Epidemic Diarrhea Virus Replication.
Integrated analysis of RNA methylation regulators crosstalk and immune infiltration for predictive and personalized therapy of diabetic nephropathy.
NSUN2 alleviates doxorubicin-induced myocardial injury through Nrf2-mediated antioxidant stress.

Ann Transl Med. 2023 Jan 15. 11(1): 15

The m6A demethylase FTO promotes keloid formation by up-regulating COL1A1.

Shuai Ren, Yingchang Ji, Mengmeng Wang, Maodong Ye, Lvdong Huang, Xiangna Cai.

   Background: Keloid is a dermal fibrotic disease characterized by excessive proliferation of dermal fibroblasts and deposition of excessive collagen. N6-methyladenosine (m6A) plays a significant role in numerous physiological and pathological regulatory processes in the human body. Fat mass and obesity-associated protein (FTO) is one of the most essential m6A demethylases. However, whether FTO has a regulatory role in keloid development remains to be determined.
Methods: In this study, we investigated the effects of the m6A demethylase FTO on keloid formation by performing hematoxylin and eosin (H&E) staining, m6A dot blotting, transwell migration experiment, and methylated RNA immunoprecipitation quantitative polymerase chain reaction (MeRIP-qPCR) tests, as well as real-time PCR (RT-PCR) and Western blot assays.
Results: The H&E staining indicated abnormal arrangement and proliferation of fibroblasts in the keloid tissue. The m6A dot blotting and qPCR revealed lower levels of m6A modification and increased expression of the m6A demethylases FTO in keloid tissue. Furthermore, overexpression of FTO promoted fibroblast migration as well as the expression of collagen type I alpha 1 chain (COL1A1) and α-smooth muscle actin (α-SMA). Mechanistic experiments demonstrated that FTO enhances keloid formation by modulating COL1A1 m6A modification and messenger RNA (mRNA) stability. In addition, this study also revealed the role of FTO in the therapeutic effect of glucocorticoids on keloids.
Conclusions: Our study demonstrates that FTO upregulates COL1A1 expression via regulating COL1A1 m6A modification and maintaining mRNA stability, hence promoting keloid development and providing a potential new therapeutic target for the treatment of keloids.

Keywords:  Keloid; N6-methyladenosine (m6A); fat mass and obesity-associated protein (FTO)

DOI:  https://doi.org/10.21037/atm-22-6021
Oncogene. 2023 Feb 08.

METTL3 stabilization by PIN1 promotes breast tumorigenesis via enhanced m6A-dependent translation.

Poshan Yugal Bhattarai, Garam Kim, Sung-Chul Lim, Ramesh Mariappan, Takbum Ohn, Hong Seok Choi.

Methyltransferase-like 3 (METTL3) is the catalytic subunit of the N6-adenosine methyltransferase complex responsible for N6-methyladenosine (m6A) modification of mRNA in mammalian cells. Although METTL3 expression is increased in several cancers, the regulatory mechanisms are unclear. We explored the regulatory roles of peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (PIN1) in METTL3 stability and m6A modification of mRNA. PIN1 interacted with METTL3 and prevented its ubiquitin-dependent proteasomal and lysosomal degradation. It stabilized METTL3, which increased the m6A modification of transcriptional coactivator with PDZ-binding motif (TAZ) and epidermal growth factor receptor (EGFR) mRNA, resulting in their efficient translation. PIN1 knockout altered the distribution of TAZ and EGFR mRNA from polysomes into monosomes. Inhibition of MEK1/2 kinases and PIN1 destabilized METTL3, which impeded breast cancer cell proliferation and induced cell cycle arrest at the G0/G1 phases. METTL3 knockout reduced PIN1 overexpression-induced colony formation in MCF7 cells and enhanced tumor growth in 4T1 cells in an orthotopic mouse model. In clinical settings, METTL3 expression significantly increased with tumor progression and was positively correlated with PIN1 expression in breast cancer tissues. Thus, PIN1 plays a regulatory role in mRNA translation, and the PIN1/METTL3 axis may be an alternative therapeutic target in breast cancer.

DOI: https://doi.org/10.1038/s41388-023-02617-6
Breast Cancer Res. 2023 Feb 10. 25(1): 19

METTL3 depletion contributes to tumour progression and drug resistance via N6 methyladenosine-dependent mechanism in HR+HER2-breast cancer.

Dengjie Ouyang, Tao Hong, Mengdie Fu, Yitong Li, Liyun Zeng, Qitong Chen, Hongye He, Ying Wen, Yan Cheng, Meirong Zhou, Qiongyan Zou, Wenjun Yi.

   BACKGROUND: Chemotherapy is an important strategy for the treatment of hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+HER2-) breast cancer (BC), but this subtype has a low response rate to chemotherapy. Growing evidence indicates that N6-methyladenosine (m6A) is the most common RNA modification in eukaryotic cells and that methyltransferase-like 3 (METTL3) participates in tumour progression in several cancer types. Therefore, exploring the function of METTL3 in HR+HER2- BC initiation and development is still important.
METHODS: mRNA and protein expression levels were analysed by quantitative real-time polymerase chain reaction and western blotting, respectively. Cell proliferation was detected by CCK-8 and colony formation assays. Cell cycle progression was assessed by flow cytometry. Cell migration and invasion were analysed by wound healing assays and transwell assays, respectively, and apoptosis was analysed by TUNEL assays. Finally, m6A modification was analysed by methylated RNA immunoprecipitation.
RESULTS: Chemotherapy-induced downregulation of the m6A modification is regulated by METTL3 depletion in HR+HER2- BC. METTL3 knockdown in MCF-7/T47D cells decreased the drug sensitivity of HR+HER2- BC cells by promoting tumour proliferation and migration and inhibiting apoptosis. Mechanistically, CDKN1A is a downstream target of METTL3 that activates the AKT pathway and promotes epithelial-mesenchymal transformation (EMT). Moreover, a decrease in BAX expression was observed when m6A modification was inhibited with METTL3 knockdown, and apoptosis was inhibited by the reduction of caspase-3/-9/-8.
CONCLUSION: METTL3 depletion promotes the proliferation and migration and decreases the drug sensitivity of HR+HER2- BC via regulation of the CDKN1A/EMT and m6A-BAX/caspase-9/-3/-8 signalling pathways, which suggests METTL3 played a tumour-suppressor role and it could be a potential biomarker for predicting the prognosis of patients with HR+HER2- BC.

Keywords:  Apoptosis; Drug sensitivity; EMT; HR+HER2− breast cancer; METTL3; m6A modification

DOI:  https://doi.org/10.1186/s13058-022-01598-w
Mol Med. 2023 Feb 06. 29(1): 19

Methyltransferase-like 3 aggravates endoplasmic reticulum stress in preeclampsia by targeting TMBIM6 in YTHDF2-dependent manner.

Yangyang Chen, Xiaoxia Liu, Lun Li, Xiyang He, Fanghui Zheng, Yang Zhang, Hui Gao, Zhishan Jin, Di Wu, Qianhua Wang, Hui Tao, Yin Zhao, Weifang Liu, Li Zou.

   BACKGROUND: With the increasing morbidity and mortality of preeclampsia (PE), it has posed a huge challenge to public health. Previous studies have reported endoplasmic reticulum (ER) stress could contribute to trophoblastic dysfunction which was associated with the N6-methyladenosine (m6A) modification by methyltransferase-like 3 (METTL3), resulting in PE. However, little was known about the relationship between METTL3 and ER stress in PE. Thus, in vitro and in vivo studies were performed to clarify the mechanism about how METTL3 affects the trophoblasts under ER stress in PE and to explore a therapeutic approach for PE.
METHODS: An ER stress model in HTR-8/SVneo cells and a preeclamptic rat model were used to study the mechanism and explore a therapeutic approach for PE. Western blot, immunohistochemistry, quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and methylated RNA immunoprecipitation (MeRIP)-qPCR were performed to detect the protein, RNA, and methylated transmembrane BAX inhibitor motif containing 6 (TMBIM6) expression levels. The m6A colorimetric and mRNA stability assays were used to measure the m6A levels and TMBIM6 stability, respectively. Short hairpin RNAs (shRNAs) were used to knockdown METTL3 and YTH N6-methyladenosine RNA binding protein 2 (YTHDF2). Flow cytometry and Transwell assays were performed to evaluate the apoptosis and invasion abilities of trophoblasts.
RESULTS: Upregulated METTL3 and m6A levels and downregulated TMBIM6 levels were observed in preeclamptic placentas under ER stress. The ER stress model was successfully constructed, and knockdown of METTL3 had a beneficial effect on HTR-8/SVneo cells under ER stress as it decreased the levels of methylated TMBIM6 mRNA. Moreover, overexpression of TMBIM6 was beneficial to HTR-8/SVneo cells under ER stress as it could neutralize the harmful effects of METTL3 overexpression. Similar to the knockdown of METTL3, downregulation of YTHDF2 expression resulted in the increased expression and mRNA stability of TMBIM6. Finally, improved systemic symptoms as well as protected placentas and fetuses were demonstrated in vivo.
CONCLUSIONS: METTL3/YTHDF2/TMBIM6 axis exerts a significant role in trophoblast dysfunction resulting in PE while inhibiting METTL3 may provide a novel therapeutic approach for PE.

Keywords:  Endoplasmic reticulum stress; METTL3; Preeclampsia; TMBIM6; YTHDF2; m6A methylation

DOI:  https://doi.org/10.1186/s10020-023-00604-x
Front Mol Neurosci. 2022 ;15 1013076

N6-methyladenosine modulation classes and immune microenvironment regulation in ischemic stroke.

Hongmiao Tao, Lihua Dong, Lin Li.

  N6-methyladenosine (m6A) modifications play an important role in the differentiation and regulation of immune cells. However, research on m6A in ischemic stroke (IS) is still in its infancy, and their role of the immune microenvironment remains unknown. In this study, we systematically assessed the modification classes of m6A regulators in IS based on the GEO database (GSE16561 and GSE22255). We found that in IS patients, IGF2BP2, IGF2BP1, and YTHDF2 expression was significantly upregulated, and ELAVL1, LRPPRC, METTL3, ALKBH5, CBLL1, and METTL14 expression was significantly downregulated. Seven IS-related genes (ELAVL1, IGF2BP2, LRPPRC, YTHDF2, ALKBH5, METTL14, and YTHDC1) were finally screened by logistic and least absolute shrinkage and selection operator (LASSO) regressions, and the AUC of the riskScore was 0.942, which was a good classification. For immune infiltration, there were highly significant differences in memory B cells, CD8 T cells, monocytes, activated dendritic cells, and mast cells between IS and normal samples. The IS samples were grouped into three classes by consistent clustering, and 15 m6A genes were differentially expressed in the different classes. Multiple infiltrating immune cells, immune-associated genes, and HLA-associated genes differed significantly across m6A modification classes, indicating the diversity and complexity of m6A modifications in the immune microenvironment of IS. Finally, 487 genes associated with the m6A modification class were identified, and 227 potential drugs were found. Our findings demonstrated that m6A modification plays a crucial role in the immune regulation of IS.

Keywords:  GEO; class; immune; ischemic stroke; m6A

DOI:  https://doi.org/10.3389/fnmol.2022.1013076
Int J Mol Sci. 2023 Jan 23. pii: 2265. [Epub ahead of print]24(3):

N6-methyladenosine Modification of Hepatitis B Virus RNA in the Coding Region of HBx.

Takayuki Murata, Satoko Iwahori, Yusuke Okuno, Hironori Nishitsuji, Yusuke Yanagi, Koichi Watashi, Takaji Wakita, Hiroshi Kimura, Kunitada Shimotohno.

  N6-methyladenosine (m6A) is a post-transcriptional modification of RNA involved in transcript transport, degradation, translation, and splicing. We found that HBV RNA is modified by m6A predominantly in the coding region of HBx. The mutagenesis of methylation sites reduced the HBV mRNA and HBs protein levels. The suppression of m6A by an inhibitor or knockdown in primary hepatocytes decreased the viral RNA and HBs protein levels in the medium. These results suggest that the m6A modification of HBV RNA is needed for the efficient replication of HBV in hepatocytes.

Keywords:  HBV; RNA; m6A modification; primary hepatocyte

DOI:  https://doi.org/10.3390/ijms24032265
Cancers (Basel). 2023 Feb 02. pii: 957. [Epub ahead of print]15(3):

F-Box Protein 43, Stabilized by N6-Methyladenosine Methylation, Enhances Hepatocellular Carcinoma Cell Growth and Invasion via Promoting p53 Degradation in a Ubiquitin Conjugating Enzyme E2 C-Dependent Manner.

Huijun Zhou, Chong Zeng, Jie Liu, Haijun Luo, Wei Huang.

  The roles of F-box protein 43 (FBXO43) in carcinogenesis have been rarely revealed. The present study investigates the expression, function, and underlying mechanism of FBXO43 in hepatocellular carcinoma (HCC). Firstly, the expression and clinical significance of FBXO43 in HCC were investigated bioinformatically and experimentally using online omics data and local tissue samples. The role of N6-methyladenosine modification (m6A) of mRNA in regulating FBXO43 expression and the effects of m6A/FBXO43 axis alteration on cell proliferation and invasion were investigated further. Moreover, the underlying mechanism of the oncogenic FBXO43 was also explored. The results demonstrated that FBXO43 was significantly upregulated in HCC and was positively correlated with advanced progression and poor prognosis in patients. METTL3 and IGF2BP2 expressions were positively correlated with FBXO43 expression and served as the writer and reader of FBXO43 m6A, respectively, which stabilized and upregulated FBXO43 mRNA in HCC. FBXO43 silencing significantly reduced cell proliferation and invasion, and ectopic expression of FBXO43 could significantly restore the inhibitory effects caused by METTL3 and IGF2BP2 depletion in HCC cells. Mechanistically, FBXO43 depletion reduced the expression of UBE2C, a p53 ubiquitin-conjugating enzyme, suppressed proteasomal degradation of p53, and thus inhibited cell proliferation and invasion in HCC. In summary, the present study revealed that METTL3/IGF2BP2 mediated m6A contributed to the upregulation of FBXO43 that promoted the malignant progression of HCC by stimulating p53 degradation in a UBE2C-dependent manner, highlighting the promising application of FBXO43 as a target in HCC treatment.

Keywords:  FBXO43; HCC; UBE2C; m6A modification; p53

DOI:  https://doi.org/10.3390/cancers15030957
Cell Death Dis. 2023 Feb 07. 14(2): 91

RBM3 suppresses stemness remodeling of prostate cancer in bone microenvironment by modulating N6-methyladenosine on CTNNB1 mRNA.

Shouyi Zhang, Chengcheng Lv, Yichen Niu, Changqi Li, Xiuming Li, Yu Shang, Yunchao Zhang, Yue Zhang, Yong Zhang, Yu Zeng.

Bone metastasis is the most happened metastatic event in prostate cancer (PCa) and needs a large effort in treatment. When PCa metastasizes to the bone, the new microenvironment can induce the epigenome reprogramming and stemness remodeling of cancer cells, thereby increasing the adaptability of cancer cells to the bone microenvironment, and this even leads to the occurrence of secondary tumor metastasis. Our group has previously found that RNA binding motif 3 (RBM3) affects the stem cell-like properties of PCa by interfering with alternative splicing of CD44. However, whether RBM3, as a stress-response protein, can resist microenvironmental remodeling of PCa particularly in bone metastasis remains unknown. By co-culturing PCa cells with osteoblasts to mimic PCa bone metastases, we found that RBM3 upregulates the N6-methyladenosine (m6A) methylation on the mRNA of catenin beta 1 (CTNNB1) in a manner dependent on methyltransferase 3 (METTL3), an N6-adenosine-methyltransferase complex catalytic subunit. Consequently, this modification results in a decreased stability of CTNNB1 mRNA and a followed inactivation of Wnt signaling, which ultimately inhibits the stemness remodeling of PCa cells by osteoblasts. Thus, the present study may extend our understanding of the inhibitory role of RBM3 on particularly bone metastasis of PCa.

DOI: https://doi.org/10.1038/s41419-023-05627-0
RNA. 2023 Feb 09. pii: rna.079554.122. [Epub ahead of print]

m6A-ELISA, a simple method for quantifying N6-methyladenosine from mRNA populations.

Imke Ensinck, Theodora Sideri, Miha Modic, Charlotte Capitanchik, Claudia Vivori, Patrick Toolan-Kerr, Folkert van Werven.

  N6-methyladenosine (m6A) is a widely studied and abundant RNA modification. The m6A mark regulates the fate of RNAs in various ways, which in turn, drives changes in cell physiology, development, and disease pathology. Over the last decade, numerous methods have been developed to map and quantify m6A sites genome-wide through deep sequencing. Alternatively, m6A levels can be quantified from a population of RNAs using techniques such as liquid chromatography-mass spectrometry or thin layer chromatography. However, many methods for quantifying m6A levels involve extensive protocols and specialized data analysis, and often only a few samples can be handled in a single experiment. Here, we developed a simple method for determining relative m6A levels in mRNA populations from various sources based on enzyme-linked immunosorbent-based assay (m6A-ELISA). We have optimized various steps of m6A-ELISA such as sample preparation and the background signal resulting from the primary antibody. We validated the method using mRNA populations from budding yeast and mouse embryonic stem cells. The full protocol takes less than a day, requiring only 25 ng of mRNA. The m6A-ELISA protocol is quick, cost-effective, and scalable, making it a valuable tool for determining relative m6A levels in samples from various sources that could be adapted to detect other mRNA modifications.

Keywords:  ELISA; m6A; mESC; yeast

DOI:  https://doi.org/10.1261/rna.079554.122
Signal Transduct Target Ther. 2023 Feb 10. 8(1): 63

O-GlcNAcylation of YTHDF2 promotes HBV-related hepatocellular carcinoma progression in an N6-methyladenosine-dependent manner.

Yang Yang, Yu Yan, Jiaxin Yin, Ni Tang, Kai Wang, Luyi Huang, Jie Hu, Zhongqi Feng, Qingzhu Gao, Ailong Huang.

Hepatitis B virus (HBV) infection is a major risk factor for hepatocellular carcinoma (HCC), but its pathogenic mechanism remains to be explored. The RNA N6-methyladenosine (m6A) reader, YTH (YT521-B homology) domain 2 (YTHDF2), plays a critical role in the HCC progression. However, the function and regulatory mechanisms of YTHDF2 in HBV-related HCC remain largely elusive. Here, we discovered that YTHDF2 O-GlcNAcylation was markedly increased upon HBV infection. O-GlcNAc transferase (OGT)-mediated O-GlcNAcylation of YTHDF2 on serine 263 enhanced its protein stability and oncogenic activity by inhibiting its ubiquitination. Mechanistically, YTHDF2 stabilized minichromosome maintenance protein 2 (MCM2) and MCM5 transcripts in an m6A-dependent manner, thus promoting cell cycle progression and HBV-related HCC tumorigenesis. Moreover, targeting YTHDF2 O-GlcNAcylation by the OGT inhibitor OSMI-1 significantly suppressed HCC progression. Taken together, our findings reveal a new regulatory mechanism for YTHDF2 and highlight an essential role of YTHDF2 O-GlcNAcylation in RNA m6A methylation and HCC progression. Further description of the molecular pathway has the potential to yield therapeutic targets for suppression of HCC progression due to HBV infection.

DOI: https://doi.org/10.1038/s41392-023-01316-8
J Formos Med Assoc. 2023 Feb 02. pii: S0929-6646(22)00477-6. [Epub ahead of print]

Overexpressed ZC3H13 suppresses papillary thyroid carcinoma growth through m6A modification-mediated IQGAP1 degradation.

Rong Xie, Wanzhi Chen, Yunxia Lv, Debin Xu, Da Huang, Tao Zhou, Shuyong Zhang, Chengfeng Xiong, Jichun Yu.

   PURPOSE: The purpose of this study was to clarify the effect of ZC3H13 on the growth of papillary thyroid carcinoma (PTC).
METHODS: Firstly, we used qRT-PCR and Western blot to compare the difference in the expression of ZC3H13 between normal thyroid epithelial cells and PTC cell lines. Then, ZC3H13 overexpression/knockout thyroid cancer cells were constructed by lentivirus transfection, and the effects of overexpression of ZC3H13 on the proliferation, migration and invasion of PTC cells were detected by CCK8 and transwell experiments. Lastly, MeRIP-qPCR, RIP and o Actinomycin D were used to verify that ZC3H13 regulated the expression of downstream target gene IQGAP1 through m6A modification.
RESULTS: ZC3H13 expression was decreased in PTC cell lines BCPAP, KTC-1, k1, HTH83, and TPC-1. Proliferation, invasion, and migration of PTC cells were inhibited by overexpressed ZC3H13 but increased by knockdown of ZC3H13. IQGAP1 expression was suppressed by ZC3H13 overexpression but enhanced by ZC3H13 knockdown. In ZC3H13-overexpressed PTC cells, the m6A level of IQGAP1 mRNA was increased, and the IQGAP1 mRNA expression was decreased with the increasing time of Actinomycin D treatment. YTHDF2 enriched more IQGAP1 mRNA than IgG and knockdown of YTHDF2 reversed the effect of ZC3H13 overexpression on IQGAP1 mRNA stability. The xenograft tumor experiment in nude mice confirmed that the overexpression of ZC3H13 inhibited tumor growth, while overexpression of IQGAP1 could reverse the inhibitory effect of ZC3H13 overexpression on tumor growth.
CONCLUSION: ZC3H13 mediates IQGAP1 mRNA degradation by promoting m6A modification of IQGAP1 mRNA, this provides a prospective therapeutic target for PTC.

Keywords:  IQGAP1; Papillary thyroid carcinoma; ZC3H13; m6A modification

DOI:  https://doi.org/10.1016/j.jfma.2022.12.019
FASEB J. 2023 Mar;37(3): e22803

METTL3 inhibits autoreactive Th17 cell responses in experimental autoimmune uveitis via stabilizing ASH1L mRNA.

Lu Zhao, Yuling Liu, Binyun Ma, Xun Liu, Ruihua Wei, Hong Nian.

  Methyltransferase like 3 (METTL3), a primary N6-methyladenosine (m6A) methyltransferase, has been implicated in various biological and pathological processes including immune responses. However, the functions and mechanisms of METTL3 in pathogenic T helper (Th)17 cells are poorly understood. Here we found significantly decreased METTL3 expression along with reduced m6A levels in eyeballs and T cells of experimental autoimmune uveitis (EAU). Overexpression of METTL3 ameliorated the development of EAU and suppressed pathogenic Th17 cell responses in vivo and in vitro. Mechanistically, METTL3 promoted the expression of absent, small, or homeotic-like 1 (ASH1L) via enhancing its stability in a YT521-B homology domain containing 2 (YTHDC2)-dependent manner, which further decreased the expression of IL-17 and IL-23 receptor (IL-23R), resulting in reduced pathogenic Th17 responses. Together, our data reveal a pivotal role of METTL3 in regulating pathogenic Th17 responses, which may contribute to human uveitis therapy.

Keywords:  ASH1L; METTL3; YTHDC2; m6A; pathogenic Th17 cells

DOI:  https://doi.org/10.1096/fj.202201548R
Environ Sci Technol. 2023 Feb 06.

Metal Exposure Promotes Colorectal Tumorigenesis via the Aberrant N6-Methyladenosine Modification of ATP13A3.

Shuwei Li, Shenya Xu, Yehua Chen, Jieyu Zhou, Shuai Ben, Mengfan Guo, Haiyan Chu, Dongying Gu, Zhengdong Zhang, Meilin Wang.

  Element contamination, including that from heavy metals, is associated with gastrointestinal tumorigenesis, but the effects and mechanisms of crucial element exposure associated with colorectal cancer remain unclear. We profiled 56 elements by ICP-MS and used logistic regression, LASSO, BKMR, and GAM to identify colorectal cancer-relevant elements. A series of biochemical experiments were performed to demonstrate the cytotoxicity and the mechanisms of malignant transformation after metal exposure. Using an elementomics approach, we first found that the metal thallium (Tl) was positively correlated with many toxic metals and was associated with a significantly increased risk of colorectal cancer. Acute exposure to Tl induced cytotoxicity and cell death by accelerating the generation of reactive oxygen species and DNA damage. Chronic exposure to Tl led to the inhibition of cell death and thereby induced the malignant transformation of normal colon cells and xenograft tumor formation in nude mice. Furthermore, we describe the first identification of a significant metal quantitative trait locus for the novel colorectal cancer susceptibility locus rs1511625 near ATP13A3. Mechanistically, Tl increased the level of aberrant N6-methyladenosine (m6A) modification of ATP13A3 via the METLL3/METTL14/ALKBH5-ATP13A3 axis to promote colorectal tumorigenesis. This study provides a basis for the development of public health strategies for reducing metal exposure among populations at high risk for colorectal cancer.

Keywords:  colorectal tumorigenesis; elementomics; m6A modification; metal exposure; thallium

DOI:  https://doi.org/10.1021/acs.est.2c07389
Cell Cycle. 2023 Feb 10. 1-19

Metformin attenuates multiple myeloma cell proliferation and encourages apoptosis by suppressing METTL3-mediated m6A methylation of THRAP3, RBM25, and USP4.

Cong-Jie Chen, Jie-Yun Huang, Jian-Qing Huang, Jia-Yi Deng, Xiao-Hui Shangguan, Ai-Zhen Chen, Long-Tian Chen, Wei-Hao Wu.

  Based on the results of epidemiological and preclinical studies, metformin can improve the prognosis of patients with malignant tumors. Studies have confirmed that metformin inhibits multiple myeloma (MM) cell proliferation and promotes apoptosis. Nevertheless, the specific mechanism remains to be elucidated. MM cells were intervened with different doses of metformin to detect cell proliferation and apoptosis. Western blotting and RT-qPCR were employed to assess the expression of METTL3, METTL14, WTAP, FTO, and ALKBH5 after metformin intervention. The microarray dataset GSE29023 was retrieved from the Gene Expression Omnibus (GEO) database and calculated using the R language (limma package) to authenticate differentially expressed genes (DEGs). The database for annotation, visualization, and integrated discovery (David) was applied for GO annotation analysis of DEGs. Subsequently, the string database and Cytoscape software were applied to construct protein-protein interaction (PPI) and DEM hub gene networks. Bioinformatics analysis and MeRIP were applied to predict and test METTL3-mediated m6A levels on mRNA of THRAP3, RBM25, and USP4 in METTL3 knocked-down cells. Then rescue experiments were performed to explore effects of METTL3 and THRAP3, RBM25, or USP4 on cell proliferation and apoptosis. The effect on MM cell xenograft tumor growth was observed by injection of metformin or/and overexpression of METTL3 in in vivo experiments. Metformin decreased cell proliferation and encouraged cell apoptosis in a dose-dependent manner. Global m6A modification was elevated in MM cells compared to normal cells, which was counteracted by metformin treatment. Furthermore, THRAP3, RBM25, and USP4 were identified as possible candidate genes for metformin treatment by GSE29023 data mining. METTL3 interference impaired m6A modification on mRNA of THRAP3, RBM25, and USP4 as well as expression levels. The mRNA stability and expression of THRAP3, RBM25, and USP4 was decreased after metformin treatment, which was reversed by METTL3 overexpression. THRAP3, RBM25 or USP4 knockdown reversed the assistance of METTL3 overexpression on the malignant behavior of MM cells. Finally, upregulation of METTL3 was shown to exert facilitative effects on xenograft tumor growth by blocking metformin injection. The present study demonstrates that metformin can repress the expression of THRAP3, RBM25, and USP4 by inhibiting METTL3-mediated m6A modification, which in turn hamper cell proliferation and promotes cell apoptosis.Abbreviations: multiple myeloma (MM), Gene Expression Omnibus (GEO), differentially expressed genes (DEGs), database for annotation, visualization and integrated discovery (David), protein-protein interaction (PPI), epithelial‑mesenchymal transition (EMT), methyltransferase like 3 (METTL3), methyltransferase like 14 (METTL14), wilms tumor 1-associated protein (WTAP), methyltransferase like 16 (METTL16), acute myeloid leukemia (AML), non-small lung cancer (NSCLC), glioma stem cells (GSCs), normal bone marrow-derived plasma cells (nPCs), false discovery rate (FDR), biological process (BP), optical density (OD), horseradish peroxidase (HRP), M6A RNA immunoprecipitation assay (MeRIP).

Keywords:  GEO database; METTL3; Multiple myeloma; m6A; metformin

DOI:  https://doi.org/10.1080/15384101.2023.2170521
Oxid Med Cell Longev. 2023 ;2023 8134027

m6A Modification Mediates Endothelial Cell Responses to Oxidative Stress in Vascular Aging Induced by Low Fluid Shear Stress.

Zhijue Xu, Peng Qiu, Yihong Jiang, Jiateng Hu, Zhaoyu Wu, Jiahao Lei, Hongji Pu, Qun Huang, Xin Wang, Bo Li, Kaichuang Ye, Xinwu Lu, Guang Liu.

N6-methyladenosine (m6A) is one of the most prevalent, abundant, and internal transcriptional modification and plays essential roles in diverse cellular and physiological processes. Low fluid shear stress (FSS) is a key pathological factor for many cardiovascular diseases, which directly forces on the endothelial cells of vessel walls. So far, the alterations and functions of m6A modifications in vascular endothelial cells at the low FSS are still unknown. Herein, we performed the transcriptome-wide m6A modification profiling of HUVECs at different FSS. We found that the m6A modifications were altered earlier and more sensitive than mRNA expressions in response to FSS. The low FSS increased the m6A modifications at CDS region but decreased the m6A modifications at 3' UTR region and regulated both the mRNA expressions and m6A modifications of the m6A regulators, such as the RBM15 and EIF3A. Functional annotations enriched by the hypermethylated and hypomethylated genes at low FSS revealed that the m6A modifications were clustered in the aging-related signaling pathways of mTOR, PI3K-AKT, insulin, and ERRB and in the oxidative stress-related transcriptional factors, such as HIF1A, NFAT5, and NFE2L2. Our study provided a pilot view of m6A modifications in vascular endothelial cells at low FSS and revealed that the m6A modifications driven by low FSS mediated the cellular responses to oxidative stress and cell aging, which suggested that the m6A modifications could be the potential targets for inhibiting vascular aging at pathological low FSS.

DOI: https://doi.org/10.1155/2023/8134027
EMBO Rep. 2023 Feb 06. e55681

FTO negatively regulates the cytotoxic activity of natural killer cells.

Seok-Min Kim, Se-Chan Oh, Sun-Young Lee, Ling-Zu Kong, Jong-Hee Lee, Tae-Don Kim.

  N6 -Methyladenosine (m6 A) is the most abundant epitranscriptomic mark and plays a fundamental role in almost every aspect of mRNA metabolism. Although m6 A writers and readers have been widely studied, the roles of m6 A erasers are not well-understood. Here, we investigate the role of FTO, one of the m6 A erasers, in natural killer (NK) cell immunity. We observe that FTO-deficient NK cells are hyperactivated. Fto knockout (Fto-/- ) mouse NK cells prevent melanoma metastasis in vivo, and FTO-deficient human NK cells enhance the antitumor response against leukemia in vitro. We find that FTO negatively regulates IL-2/15-driven JAK/STAT signaling by increasing the mRNA stability of suppressor of cytokine signaling protein (SOCS) family genes. Our results suggest that FTO is an essential modulator of NK cell immunity, providing a new immunotherapeutic strategy for allogeneic NK cell therapies.

Keywords:  FTO; N6-methyladenosine; NK cell; epitranscriptome; m6A regulator

DOI:  https://doi.org/10.15252/embr.202255681
Cell Death Discov. 2023 Feb 10. 9(1): 56

Role of NAT10-mediated ac4C-modified HSP90AA1 RNA acetylation in ER stress-mediated metastasis and lenvatinib resistance in hepatocellular carcinoma.

Zhipeng Pan, Yawei Bao, Mengyao Hu, Yue Zhu, Chaisheng Tan, Lulu Fan, Hanqing Yu, Anqi Wang, Jie Cui, Guoping Sun.

Emerging evidence showed that epigenetic regulation plays important role in the pathogenesis of HCC. N4-acetocytidine (ac4C) was an acetylation chemical modification of mRNA, and NAT10 is reported to regulate ac4C modification and enhance endoplasmic reticulum stress (ERS) in tumor metastasis. Here, we report a novel mechanism by which NAT10-mediated mRNA ac4C-modified HSP90AA1 regulates metastasis and tumor resistance in ERS of HCC. Immunohistochemical, bioinformatics analyses, and in vitro and in vivo experiments, e.g., acRIP-Seq, RNA-Seq, and double luciferase reporter experiment, were employed to investigate the effect of NAT10 on metastasis and drug resistance in HCC. The increased expression of NAT10 was associated with HCC risk and poor prognosis. Cell and animal experiments showed that NAT10 enhanced the metastasis ability and apoptosis resistance of HCC cells in ERS and ERS state. NAT10 could upregulate the modification level of HSP90AA1 mRNA ac4C, maintain the stability of HSP90AA1, and upregulate the expression of HSP90AA1, which further promotes the metastasis of ERS hepatoma cells and the resistance to apoptosis of Lenvatinib. This study proposes a novel mechanism by which NAT10-mediated mRNA ac4C modification regulates tumor metastasis. In addition, we demonstrated the regulatory effect of NAT10-HSP90AA1 on metastasis and drug resistance of ERS in HCC cells.

DOI: https://doi.org/10.1038/s41420-023-01355-8
Hereditas. 2023 Feb 09. 160(1): 6

m6A-related lncRNA-based immune infiltration characteristic analysis and prognostic model for colonic adenocarcinoma.

Hao-Lun Wang, Zhuo-Miao Ye, Zi-Yun He, Lu Huang, Zhi-Hui Liu.

   BACKGROUND: Colonic adenocarcinoma (COAD) is a common gastrointestinal tract tumor, and its occurrence and progression are typically associated with genomic instability, tumor-suppressor gene and oncogene mutations, and tumor mutational load. N6-methyladenosine (m6A) modification of RNAs and long non-coding RNA (lncRNA) expression are important in tumorigenesis and progression. However, the regulatory roles of m6A-associated lncRNAs in the tumor microenvironment, stratification of prognosis, and immunotherapy are unclear.
METHODS: We screened 43 prognostic lncRNAs linked to m6A and performed consistent molecular typing of COAD using consensus clustering. The single-sample Gene Set Enrichment Analysis and ESTIMATE algorithms were used to assess the immune characteristics of different subgroups. Covariation between methylation-related prognostic lncRNAs was eliminated by least absolute shrinkage and selection operator Cox regression. A nomogram was created and evaluated by combining the methylation-related prognostic lncRNA model with other clinical factors. The relationship between the prognostic model grouping and microsatellite instability, immunophenotype score, and tumor mutation burden was validated using R scripts. Finally, we used a linkage map to filter sensitive medicines to suppress the expression of high-risk genes. Three m6A-associated lncRNA modes were identified in 446 COAD specimens with different clinical endpoints and biological statuses. Risk scores were constructed based on the m6A-associated lncRNA signature genes. Patients with lower risk scores showed superior immunotherapy responses and clinical benefits compared to those with higher risk scores. Lower risk scores were also correlated with higher immunophenotype scores, tumor mutation burden, and mutation rates in significantly mutated genes (e.g., FAT4 and MUC16). Piperidolate, quinostatin, and mecamylamin were screened for their abilities to suppress the expression of high-risk genes in the model.
CONCLUSIONS: Quantitative assessment of m6A-associated lncRNAs in single tumors can enhance the understanding of tumor microenvironment profiles. The prognostic model constructed using m6A-associated lncRNAs may facilitate prognosis and immunotherapy stratification of patients with COAD; finally, three drugs with potential therapeutic value were screened based on the model.

Keywords:  Colonic adenocarcinoma; Immune infiltration; Prognostic model; m6A-related long non-coding RNA

DOI:  https://doi.org/10.1186/s41065-023-00267-y
J Virol. 2023 Feb 07. e0153922

Fragile X-Related Protein FXR1 Controls Human Adenovirus Capsid mRNA Metabolism.

Zamaneh Hajikhezri, Yanina Kaira, Erik Schubert, Mahmoud Darweesh, Catharina Svensson, Göran Akusjärvi, Tanel Punga.

  Human adenoviruses (HAdVs) are widespread pathogens causing a variety of diseases. A well-controlled expression of virus capsid mRNAs originating from the major late transcription unit (MLTU) is essential for forming the infectious virus progeny. However, regulation of the MLTU mRNA metabolism has mainly remained enigmatic. In this study, we show that the cellular RNA-binding protein FXR1 controls the stability of the HAdV-5 MLTU mRNAs, as depletion of FXR1 resulted in increased steady-state levels of MLTU mRNAs. Surprisingly, the lack of FXR1 reduced viral capsid protein accumulation and formation of the infectious virus progeny, indicating an opposing function of FXR1 in HAdV-5 infection. Further, the long FXR1 isoform interfered with MLTU mRNA translation, suggesting FXR1 isoform-specific functions in virus-infected cells. We also show that the FXR1 protein interacts with N6-methyladenosine (m6A)-modified MLTU mRNAs, thereby acting as a novel m6A reader protein in HAdV-5 infected cells. Collectively, our study identifies FXR1 as a regulator of MLTU mRNA metabolism in the lytic HAdV-5 life cycle. IMPORTANCE Human adenoviruses (HAdVs) are common pathogens causing various self-limiting diseases, such as the common cold and conjunctivitis. Even though adenoviruses have been studied for more than 6 decades, there are still gaps in understanding how the virus interferes with the host cell to achieve efficient growth. In this study, we identified the cellular RNA-binding protein FXR1 as a factor manipulating the HAdV life cycle. We show that the FXR1 protein specifically interferes with mRNAs encoding essential viral capsid proteins. Since the lack of the FXR1 protein reduces virus growth, we propose that FXR1 can be considered a novel cellular proviral factor needed for efficient HAdV growth. Collectively, our study provides new detailed insights about the HAdV-host interactions, which might be helpful when developing countermeasures against pathogenic adenovirus infections and for improving adenovirus-based therapies.

Keywords:  FXR1; adenovirus; m6A-modification; mRNA decay; mRNA translation

DOI:  https://doi.org/10.1128/jvi.01539-22
Front Genet. 2022 ;13 1065424

RNA modification writers pattern in relation to tumor microenvironment and prognosis in prostate cancer.

Xu Cheng, Xuanzi Yi.

  Background: RNA modifications are important in the study of epigenetic regulatory mechanisms in immune responses and tumorigenesis. When RNA writers are mutated or disrupted in expression, the genes associated with the pathways they modify are also disrupted and can activate or repress related pathways, affecting tumorigenesis and progression. However, the potential role of RNA writers in prostate cancer is unclear. Methods: Based on data from three datasets, we describe 26 RNA writers that mediate gene expression and genetic mutation in prostate cancer and assess their expression patterns in 948 prostate cancer samples. Using principal component analysis algorithms, the RM Score was developed to quantify the RNA modification patterns of specific tumors. Results: Two different categories were determined by unsupervised clustering methods, and survival analysis showed significant differences in OS prognosis between these two categories. Differentially expressed genes between the different categories were detected and the RNA writers-mediated scoring model RM_Score were constructed based on this. Also, the RM_Score was analyzed in relation to clinical characteristics, immune infiltration level, drug response, and efficacy of chemotherapy and immunotherapy. Those results confirm that multilayer alterations in epitope-modified RNA writers are associated with patient prognosis and with immune cell infiltration characteristics. Finally, we examined differentially expressed mRNA, lncRNA and miRNA between high and low RM_Score groups, based on which a ceRNA regulatory network was constructed. Conclusion: This work is a comprehensive analysis of modified writers in prostate cancer and identified them to have a role in chemotherapy and immunotherapy.

Keywords:  RM_score; RNA modification writers; immunotherapy; prognosis; prostate cancer

DOI:  https://doi.org/10.3389/fgene.2022.1065424
Plants (Basel). 2023 Jan 31. pii: 624. [Epub ahead of print]12(3):

Current Insights into m6A RNA Methylation and Its Emerging Role in Plant Circadian Clock.

Nguyen Nguyen Chuong, Phan Phuong Thao Doan, Lanshuo Wang, Jin Hee Kim, Jeongsik Kim.

  N6-adenosine methylation (m6A) is a prevalent form of RNA modification found in the expressed transcripts of many eukaryotic organisms. Moreover, m6A methylation is a dynamic and reversible process that requires the functioning of various proteins and their complexes that are evolutionarily conserved between species and include methylases, demethylases, and m6A-binding proteins. Over the past decade, the m6A methylation process in plants has been extensively studied and the understanding thereof has drastically increased, although the regulatory function of some components relies on information derived from animal systems. Notably, m6A has been found to be involved in a variety of factors in RNA processing, such as RNA stability, alternative polyadenylation, and miRNA regulation. The circadian clock in plants is a molecular timekeeping system that regulates the daily and rhythmic activity of many cellular and physiological processes in response to environmental changes such as the day-night cycle. The circadian clock regulates the rhythmic expression of genes through post-transcriptional regulation of mRNA. Recently, m6A methylation has emerged as an additional layer of post-transcriptional regulation that is necessary for the proper functioning of the plant circadian clock. In this review, we have compiled and summarized recent insights into the molecular mechanisms behind m6A modification and its various roles in the regulation of RNA. We discuss the potential role of m6A modification in regulating the plant circadian clock and outline potential future directions for the study of mRNA methylation in plants. A deeper understanding of the mechanism of m6A RNA regulation and its role in plant circadian clocks will contribute to a greater understanding of the plant circadian clock.

Keywords:  FIONA1; MTA; MTB; circadian clock; epitranscriptome; m6A eraser; m6A methylation; m6A reader; m6A writer

DOI:  https://doi.org/10.3390/plants12030624
Front Immunol. 2023 ;14 1071675

Multi-omics analysis of N6-methyladenosine reader IGF2BP3 as a promising biomarker in pan-cancer.

Pin Chen, Jing Xu, Zihan Cui, Silin Wu, Tao Xie, Xiaobiao Zhang.

   Background: Insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) has been reported to exhibit an oncogenic effect as an RNA-binding protein (RBP) by promoting tumor cell proliferation, migration and invasion in several tumor types. However, a pan-cancer analysis of IGF2BP3 is not currently available, and the exact roles of IGF2BP3 in prognosis and immunology in cancer patients remain enigmatic. The main aim of this study was to provide visualization of the systemic prognostic landscape of IGF2BP3 in pan-cancer and to uncover the potential relationship between IGF2BP3 expression in the tumor microenvironment and immune infiltration profile.
Methods: Raw data on IGF2BP3 expression were obtained from GTEx, CCLE, TCGA, and HPA data portals. We have investigated the expression patterns, diagnostic and prognostic significance, mutation landscapes, functional analysis, and functional states of IGF2BP3 utilizing multiple databases, including HPA, TISIDB, cBioPortal, GeneMANIA, GESA, and CancerSEA. Moreover, the relationship of IGF2BP3 expression with immune infiltrates, TMB, MSI and immune-related genes was evaluated in pan-cancer. IGF2BP3 with drug sensitivity analysis was performed from the CellMiner database. Furthermore, the expression of IGF2BP3 in different grades of glioma was detected by immunohistochemical staining and western blot.
Results: We found that IGF2BP3 was ubiquitously highly expressed in pan-cancer and significantly correlated with diagnosis, prognosis, TMB, MSI, and drug sensitivity in various types of cancer. Besides, IGF2BP3 was involved in many cancer pathways and varied in different immune and molecular subtypes of cancers. Additionally, IGF2BP3 is critically associated with genetic markers of immunomodulators in various cancers. Finally, we validated that IGF2BP3 protein expression was significantly higher in glioma than in normal tissue, especially in GBM.
Conclusions: IGF2BP3 may be a potential molecular biomarker for diagnosis and prognosis in pan-cancer, especially for glioma. It could become a novel therapeutic target for various cancers.

Keywords:  genetic alteration; immune infiltration; insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3); pan-cancer analysis; prognosis; the Cancer Genome Atlas (TCGA)

DOI:  https://doi.org/10.3389/fimmu.2023.1071675
J Virol. 2023 Feb 08. e0175122

Heterogeneous Nuclear Protein U Degraded the m6A Methylated TRAF3 Transcript by YTHDF2 To Promote Porcine Epidemic Diarrhea Virus Replication.

Hongchao Zhou, Yuchao Yan, Jie Gao, Mingrui Ma, Yi Liu, Xiaojie Shi, Qi Zhang, Xingang Xu.

  Porcine epidemic diarrhea virus (PEDV) belongs to the genus Alphacoronavirus of the Coronaviridae family and can cause fatal watery diarrhea in piglets, causing significant economic losses. Heterogeneous nuclear protein U (HNRNPU) is a novel RNA sensor involved in sensing viral RNA in the nucleus and mediating antiviral immunity. However, it remains elusive whether and how cytoplasmic PEDV can be sensed by the RNA sensor HNRNPU. In this study we determined that HNRNPU was the binding partner of Nsp13 by immunoprecipitation-liquid chromatography-tandem mass spectrometry (IP/LC-MS/MS) analysis. The interaction between Nsp13 and HNRNPU was demonstrated by using coimmunoprecipitation and confocal immunofluorescence. Next, we identified that HNRNPU expression is significantly increased during PEDV infection, whereas the transcription factor hepatocyte nuclear factor 1α (HNF1A) could negatively regulate HNRNPU expression. HNRNPU was retained in the cytoplasm by interaction with PEDV Nsp13. We found that HNRNPU overexpression effectively facilitated PEDV replication, while knockdown of HNRNPU impaired viral replication, suggesting a promoting function of HNRNPU to PEDV infection. Additionally, HNRNPU was found to promote PEDV replication by affecting TRAF3 degradation at the transcriptional level to inhibit PEDV-induced beta interferon (IFN-β) production. Mechanistically, HNRNPU downregulates TRAF3 mRNA levels via the METTL3-METTL14/YTHDF2 axis and regulates immune responses through YTHDF2-dependent mRNA decay. Together, our findings reveal that HNRNPU serves as a negative regulator of innate immunity by degrading TRAF3 mRNA in a YTHDF2-dependent manner and consequently facilitating PEDV propagation. Our findings provide new insights into the immune escape of PEDV. IMPORTANCE PEDV, a highly infectious enteric coronavirus, has spread rapidly worldwide and caused severe economic losses. During virus infection, the host regulates innate immunity to inhibit virus infection. However, PEDV has evolved a variety of different strategies to suppress host IFN-mediated antiviral responses. Here, we identified that HNRNPU interacted with viral protein Nsp13. HNRNPU protein expression was upregulated, and the transcription factor HNF1A could negatively regulate HNRNPU expression during PEDV infection. HNRNPU also downregulated TRAF3 mRNA through the METTL3-METTL14/YTHDF2 axis to inhibit the production of IFN-β and downstream antiviral genes in PEDV-infected cells, thereby promoting viral replication. Our findings reveal a new mechanism with which PEDV suppresses the host antiviral response.

Keywords:  HNRNPU; IFN-β; PEDV; TRAF3; YTHDF2; m6A

DOI:  https://doi.org/10.1128/jvi.01751-22
Hum Genomics. 2023 Feb 10. 17(1): 6

Integrated analysis of RNA methylation regulators crosstalk and immune infiltration for predictive and personalized therapy of diabetic nephropathy.

Jia Li, Dongwei Liu, Jingjing Ren, Guangpu Li, Zihao Zhao, Huanhuan Zhao, Qianqian Yan, Jiayu Duan, Zhangsuo Liu.

   BACKGROUND: RNA methylation is a widely known post-transcriptional regulation which exists in many cancer and immune system diseases. However, the potential role and crosstalk of five types RNA methylation regulators in diabetic nephropathy (DN) and immune microenvironment remain unclear.
METHODS: The mRNA expression of 37 RNA modification regulators and RNA modification regulators related genes were identified in 112 samples from 5 Gene Expression Omnibus datasets. Nonnegative Matrix Factorization clustering method was performed to determine RNA modification patterns. The ssGSEA algorithms and the expression of human leukocyte antigen were employed to assess the immune microenvironment characteristics. Risk model based on differentially expression genes responsible for the modification regulators was constructed to evaluate its predictive capability in DN patients. Furthermore, the results were validated by using immunofluorescence co-localizations and protein experiments in vitro.
RESULTS: We found 24 RNA methylation regulators were significant differently expressed in glomeruli in DN group compared with control group. Four methylation-related genes and six RNA regulators were introduced into riskScore model using univariate Logistic regression and integrated LASSO regression, which could precisely distinguish the DN and healthy individuals. Group with high-risk score was associated with high immune infiltration. Three distinct RNA modification patterns were identified, which has significant differences in immune microenvironment, biological pathway and eGFR. Validation analyses showed the METTL3, ADAR1, DNMT1 were upregulated whereas YTHDC1 was downregulated in DN podocyte cell lines comparing with cells cultured by the normal glucose.
CONCLUSION: Our study reveals that RNA methylation regulators and immune infiltration regulation play critical roles in the pathogenesis of DN. The bioinformatic analyses combine with verification in vitro could provide robust evidence for identification of predictive RNA methylation regulators in DN.

Keywords:  Diabetic nephropathy; Epigenetics; Immune profiles; Immunotherapy; RNA methylation

DOI:  https://doi.org/10.1186/s40246-023-00457-9
Cell Death Discov. 2023 Feb 04. 9(1): 43

NSUN2 alleviates doxorubicin-induced myocardial injury through Nrf2-mediated antioxidant stress.

Yi Wang, Yuxin Zan, Yingying Huang, Xiaoyun Peng, Shinan Ma, Ji Ren, Xiao Li, Lin Wei, Xiaoli Wang, Yahong Yuan, Junming Tang, Zhongqun Zhan, Zhixiao Wang, Yan Ding.

Doxorubicin (DOX) is a commonly used antitumor drug, but its application has been limited because of its strong cardiac damage. This study aims to explore the role of NSUN2 in DOX-induced heart injury. C57BL/6J mice were intraperitoneally injected with 20 mg/Kg DOX to induce heart injury. After 3 days, the cardiac function, cardiac histopathology, myocardial apoptosis, and the expression level of NSUN2 were detected. In vitro, H9C2 cells were transfected with NSUN2 siRNA or overexpressed lentivirus and then treated with 500 ng/ml DOX. After 24 h, the changes in reactive oxygen species (ROS), apoptosis, and NSUN2 expression were detected. After DOX treatment, both in vitro and in vivo experiments showed that the cardiac function decreased, the number of apoptotic cells increased, and the expression level of NSUN2 increased. Interfering the expression of NSUN2 by siRNA promoted DOX-induced heart injury, while overexpression of NSUN2 could inhibit DOX-induced heart injury. Further study showed that NSUN2 promoted antioxidative stress by upregulating the Nrf2 protein level. In addition, NSUN2 overexpression could increase the half-life of Nrf2 mRNA. m5C RNA methylation immunoprecipitation (MeRIP) also showed that the level of Nrf2 m5C mRNA was significantly increased in NSUN2 overexpressed group when compared to the GFP group. NSUN2 enhances the expression of Nrf2 by promoting Nrf2 mRNA m5C modification and enhances its antioxidative stress effect to alleviate DOX-induced myocardial injury.

DOI: https://doi.org/10.1038/s41420-022-01294-w