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1.
Mol Cell ; 81(16): 3339-3355.e8, 2021 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-34352206

RESUMO

Cancer cells selectively promote translation of specific oncogenic transcripts to facilitate cancer survival and progression, but the underlying mechanisms are poorly understood. Here, we find that N7-methylguanosine (m7G) tRNA modification and its methyltransferase complex components, METTL1 and WDR4, are significantly upregulated in intrahepatic cholangiocarcinoma (ICC) and associated with poor prognosis. We further reveal the critical role of METTL1/WDR4 in promoting ICC cell survival and progression using loss- and gain-of-function assays in vitro and in vivo. Mechanistically, m7G tRNA modification selectively regulates the translation of oncogenic transcripts, including cell-cycle and epidermal growth factor receptor (EGFR) pathway genes, in m7G-tRNA-decoded codon-frequency-dependent mechanisms. Moreover, using overexpression and knockout mouse models, we demonstrate the crucial oncogenic function of Mettl1-mediated m7G tRNA modification in promoting ICC tumorigenesis and progression in vivo. Our study uncovers the important physiological function and mechanism of METTL1-mediated m7G tRNA modification in the regulation of oncogenic mRNA translation and cancer progression.


Assuntos
Colangiocarcinoma/genética , Proteínas de Ligação ao GTP/genética , Metiltransferases/genética , Biossíntese de Proteínas , Animais , Carcinogênese/genética , Colangiocarcinoma/patologia , Progressão da Doença , Receptores ErbB/genética , Guanosina/análogos & derivados , Guanosina/genética , Humanos , Camundongos , Processamento Pós-Transcricional do RNA/genética , RNA Mensageiro/genética , RNA de Transferência/genética
2.
Int Immunopharmacol ; 96: 107611, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33882443

RESUMO

OBJECTIVE: Exosomes are known to transfer microRNAs (miRNAs) to affect the progression of human diseases. We aim to explore the role of M1 macrophages-derived exosomes (M1 exosomes) conveying miR-21-5p in ventricular remodeling in mice with myocardial infarction (MI) by regulating tissue inhibitors of metalloproteinase 3 (TIMP3). METHODS: Macrophages were isolated and co-cultured with miR-21-5p antagomir to extract the exosomes. The modeled mice were injected with relative exosomes to investigate their roles in the cardiac function, pathology of myocardial tissue, myocardial fibrosis, cardiomyocyte apoptosis and ventricular remodeling in MI mice. The expression of miR-21-5p and TIMP3 was detected and their targeting relationship was analyzed. RESULTS: MiR-21-5p was upregulated while TIMP3 was downregulated in MI mouse myocardial tissues. M1 exosomes impaired cardiac function, aggravated pathology of myocardial tissue, myocardial fibrosis and ventricular remodeling, and promoted cardiomyocyte apoptosis in MI mice. M1 exosomes containing miR-21-5p antagomir alleviated the above alterations, while the role of exosomes containing miR-21-5p antagomir was reversed by silencing TIMP3. TIMP3 was targeted by miR-21-5p. CONCLUSION: Downregulation of miR-21-5p from macrophages-derived exosomes suppresses ventricular remodeling after MI via inhibiting TIMP3.

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