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Feng Z, Li Q, Meng R, Yi B, Xu Q. METTL3 regulates alternative splicing of MyD88 upon the lipopolysaccharide-induced inflammatory response in human dental pulp cells. J Cell Mol Med 2018; 22:2558-2568. [PMID: 29502358 PMCID: PMC5908103 DOI: 10.1111/jcmm.13491] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 11/13/2017] [Indexed: 12/30/2022] Open
Abstract
Dental pulp inflammation is a widespread public health problem caused by oral bacterial infections and can progress to pulp necrosis and periapical diseases. N6‐methyladenosine (m6A) is a prevalent epitranscriptomic modification in mRNA. Previous studies have demonstrated that m6A methylation plays important roles in cell differentiation, embryonic development and stress responses. However, whether m6A modification affects dental pulp inflammation remains unknown. To address this issue, we investigated the expression of m6A and N6‐adenosine methyltransferase (METTL3, METTL14) as well as demethylases (FTO, ALKBH5) and found that the levels of m6A and METTL3 were up‐regulated in human dental pulp cells (HDPCs) stimulated by lipopolysaccharide (LPS). Furthermore, we knocked down METTL3 and demonstrated that METTL3 depletion decreased the expression of inflammatory cytokines and the phosphorylation of IKKα/β, p65 and IκBα in the NF‐κB signalling pathway as well as p38, ERK and JNK in the MAPK signalling pathway in LPS‐induced HDPCs. The RNA sequencing analysis revealed that the vast number of genes affected by METTL3 depletion was associated with the inflammatory response. Previous research has shown that METTL3‐dependent N6‐adenosine methylation plays an important role in mRNA splicing. In this study, we found that METTL3 knockdown facilitated the expression of MyD88S, a splice variant of MyD88 that inhibits inflammatory cytokine production, suggesting that METTL3 might inhibit the LPS‐induced inflammatory response of HDPCs by regulating alternative splicing of MyD88. These data shed light on new findings in epitranscriptomic regulation of the inflammatory response and open new avenues for research into the molecular mechanisms of dental pulp inflammation.
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Affiliation(s)
- Zhihui Feng
- Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Qimeng Li
- Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Runsha Meng
- Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Baicheng Yi
- Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Qiong Xu
- Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
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Backlund PS, Carotti D, Cantoni GL. Effects of the S-adenosylhomocysteine hydrolase inhibitors 3-deazaadenosine and 3-deazaaristeromycin on RNA methylation and synthesis. EUROPEAN JOURNAL OF BIOCHEMISTRY 1986; 160:245-51. [PMID: 3769925 DOI: 10.1111/j.1432-1033.1986.tb09963.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The effects of 3-deazaaristeromycin and 3-deazaadenosine on RNA methylation and synthesis were examined in the mouse macrophage cell line, RAW264. S-Adenosylhomocysteine accumulated in cells incubated with 3-deazaaristeromycin while S-3-deazaadenosylhomocysteine was the major product in cells incubated with 3-deazaadenosine and homocysteine thiolactone. RNA methylation was inhibited to a similar extent by the accumulation of either S-adenosylhomocysteine or S-3-deazaadenosylhomocysteine, with S-adenosylhomocysteine being a slightly better inhibitor. In mRNA, the synthesis of N6-methyladenosine and N6-methyl-2'-O-methyladenosine were inhibited to the greatest extent, while the synthesis of 7-methylguanosine and 2'-O-methyl nucleosides were inhibited to a lesser extent. Incubation of cells with 100 microM 3-deazaaristeromycin or with 10 microM 3-deazaadenosine and 50 microM homocysteine thiolactone produced little inhibition of mRNA synthesis, even though mRNA methylation was inhibited. In contrast, mRNA synthesis was greatly inhibited by treatment of cells with 100 microM 3-deazaadenosine and the inhibition of synthesis was not correlated with an inhibition of methylation.
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Locht C, Delcour J. In vitro methylation of undermethylated yeast poly(A)-rich RNA using mRNA(guanine-7-)-methyltransferase purified from wheat germ or yeast. EUROPEAN JOURNAL OF BIOCHEMISTRY 1985; 152:247-51. [PMID: 2414101 DOI: 10.1111/j.1432-1033.1985.tb09190.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
By crossing two strains of Saccharomyces cerevisiae deficient for each of the two methionine adenosyltransferase isoenzymes (ATP: L-methionine S-adenosyltransferase EC 2.5.1.6) respectively, we have constructed a strain strictly auxotrophic for S-adenosylmethionine and used it as a source of undermethylated mRNA suitable for in vitro transmethylation studies. RNA has been phenol-extracted from yeast cells shifted down to S-adenosylmethionine-free medium for 90 min and poly(A)-rich RNA has been prepared by oligo(dT)-cellulose chromatography. Upon incubation in vitro in the presence of methyl-labeled S-adenosylmethionine and mRNA (guanine-7-)-methyltransferase purified from wheat germ or yeast, undermethylated poly(A)-rich RNA became significantly labeled as compared to non-starved cells from the same strain, or from a wild-type control. Cap structures were resolved by paper chromatography afer T2 and P1 RNase digestion, and shown to be a mixture of m7G5'ppp5'G and m7G5'ppp5'A, irrespective of the enzyme source, in agreement with earlier in vivo studies in yeast mRNA capping and methylation.
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Abstract
S-Tubercidinylhomocysteine (STH) is a structural analog of S-adenosylhomocysteine and a potent inhibitor of S-adenosylmethionine-dependent methyltransferase reactions. We investigated the effects of STH on HeLa cell mRNA metabolism. Dual labeling studies reveal that STH dramatically inhibits the methylation of HeLa mRNA in a dose-dependent manner. Analysis of the modified nucleosides and 5'-terminal cap structures in radiolabeled mRNA by high-pressure liquid chromatography indicated that internal N6-methylation of adenosine was reduced by 65% at 50 microM STH and by 83% at 500 microM STH. The N6-methylation of adenosine contained in cap structures was similarly reduced at both concentrations of STH. Substantial amounts of cap structures lacking 2'-O-methylated nucleosides (m7GpppN, cap zero) were detected at the higher level of STH. To test the possibility that methylation affects mRNA stability, cytoplasmic mRNA half-life was measured in a pulse-chase experiment. The half-life of undermethylated mRNA, produced as a consequence of STH treatment, was unchanged compared with the control. To determine whether mRNA methylation is coupled to nuclear processing or transport, the time of cytoplasmic appearance of polyadenylated RNA in STH-treated HeLa cells was compared with untreated cells. STH caused a significant lag in the time of appearance of the polyadenylated RNA, suggesting that mRNA methylation may be required for efficient processing or transport.
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Camper SA, Albers RJ, Coward JK, Rottman FM. Effect of undermethylation on mRNA cytoplasmic appearance and half-life. Mol Cell Biol 1984; 4:538-43. [PMID: 6201720 PMCID: PMC368733 DOI: 10.1128/mcb.4.3.538-543.1984] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
S-Tubercidinylhomocysteine (STH) is a structural analog of S-adenosylhomocysteine and a potent inhibitor of S-adenosylmethionine-dependent methyltransferase reactions. We investigated the effects of STH on HeLa cell mRNA metabolism. Dual labeling studies reveal that STH dramatically inhibits the methylation of HeLa mRNA in a dose-dependent manner. Analysis of the modified nucleosides and 5'-terminal cap structures in radiolabeled mRNA by high-pressure liquid chromatography indicated that internal N6-methylation of adenosine was reduced by 65% at 50 microM STH and by 83% at 500 microM STH. The N6-methylation of adenosine contained in cap structures was similarly reduced at both concentrations of STH. Substantial amounts of cap structures lacking 2'-O-methylated nucleosides (m7GpppN, cap zero) were detected at the higher level of STH. To test the possibility that methylation affects mRNA stability, cytoplasmic mRNA half-life was measured in a pulse-chase experiment. The half-life of undermethylated mRNA, produced as a consequence of STH treatment, was unchanged compared with the control. To determine whether mRNA methylation is coupled to nuclear processing or transport, the time of cytoplasmic appearance of polyadenylated RNA in STH-treated HeLa cells was compared with untreated cells. STH caused a significant lag in the time of appearance of the polyadenylated RNA, suggesting that mRNA methylation may be required for efficient processing or transport.
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Langberg S, Moss B. Post-transcriptional modifications of mRNA. Purification and characterization of cap I and cap II RNA (nucleoside-2'-)-methyltransferases from HeLa cells. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)68740-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Gillies S, Stollar V. Biochemical characterization of vesicular stomatitis virus-infected Aedes albopictus cells deprived of methionine. Virology 1981; 112:318-27. [PMID: 6264688 DOI: 10.1016/0042-6822(81)90637-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Albers RJ, Coffin B, Rottman FM. Analysis of mRNA 5'-terminal cap structures and internal N6-methyladenosine by reversed-phase high-performance liquid chromatography. Anal Biochem 1981; 113:118-23. [PMID: 6115593 DOI: 10.1016/0003-2697(81)90053-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Harper JF, Clancy MJ, Magee PT. Properties of polyadenylate-associated ribonucleic acid from Saccharomyces cerevisiae ascospores. J Bacteriol 1980; 143:958-65. [PMID: 7009568 PMCID: PMC294400 DOI: 10.1128/jb.143.2.958-965.1980] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Bulk ribonucleic acid (RNA) was isolated from mechanically disrupted ascospores of Saccharomyces cerevisiae. After two passes over an oligo (dT10) cellulose column, the portion which bound, called poly(A)(+), was characterized. It is heterodisperse in size with a mean molecular weight of approximately 4 X 10(5), but contains some species as large as 7 X 10(5). The base composition is similar to vegetative poly(A)(+) RNA. The polyadenylate segment is also heterogenous in size, ranging from 90 to 20 bases in length, with a peak at approximately 60 nucleotides in length. Pulse-labeling of asci with [3H-methyl]methionine yields two "caps," 7-methyl guanosine-5'-triphosphoryl-5'-adenosine (or guanosine) identical to that found in vegetative poly(A)(+) RNA. The poly(A)(+) RNA in spores is found in polyribosomes which are, on the average, smaller than vegetative ones. Long-term labeling studies indicate that the fraction of poly(A)(+) RNA in spores is similar to that in vegetative cells.
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Breter HJ, Malek LT, Hellmann GM, Rhoads RE. Determination of 7-methylguanosine-containing 5'-termini of messenger ribonucleic acid by NaB[3H]4 labeling and high-performance liquid anion-exchange chromatography. Anal Biochem 1979; 98:102-11. [PMID: 120686 DOI: 10.1016/0003-2697(79)90712-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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12
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Determination of 5-hydroxytryptamine metabolites in isolated perfused rabbit lung by high-performance liquid chromatography. Anal Biochem 1979. [DOI: 10.1016/s0003-2697(79)80128-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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13
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Bader JP, Brown NR, Chiang PK, Cantoni GL. 3-Deazaadenosine, an inhibitor of adenosylhomocysteine hydrolase, inhibits reproduction of Rous sarcoma virus and transformation of chick embryo cells. Virology 1978; 89:494-505. [PMID: 213879 DOI: 10.1016/0042-6822(78)90191-5] [Citation(s) in RCA: 75] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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14
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Bachellerie JP, Amalric F, Caboche M. Biosynthesis and utilization of extensively undermethylated poly(A)+ RNA in CHO cells during a cycloleucine treatment. Nucleic Acids Res 1978; 5:2927-43. [PMID: 693324 PMCID: PMC342216 DOI: 10.1093/nar/5.8.2927] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The role of RNA methylations in the control of mRNA maturation and incorporation into polysomes has been investigated through a study of the effects in vivo of cycloleucine, a specific inhibitor of S-adenosyl-methionine mediated methylation. During the cycloleucine treatment, the rate of biosynthesis of hnRNA and its subsequent polyadenylation were only slightly reduced as compared with untreated cells. However a significant lag-time in the cytoplasmic appearance of poly(A)+ undermethylated molecules was observed, in parallel with a transient shift in the average size of hnRNA towards higher molecular weight. Nevertheless, the total amount of pulse-labelled poly(A)+ mRNA transferred to cytoplasm after a long chase time (3 h.) was approximately the same for both cycloleucine-treated and control cells. Extensively undermethylated poly(A)+ cytoplasmic RNAs, possessing a 5' terminal cap were incorporated into polysomes in proportions very similar to control messenger molecules. These results suggest that a normal level of methylation is not stringently required for the production of the functional mRNA molecules although it appears to be of importance for the kinetics of the maturational process.
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Kroath H, Gross HJ, Jungwirth C, Bodo G. RNA methylation in vaccinia virus-infected chick embryo fibroblasts treated with homologous interferon. Nucleic Acids Res 1978; 5:2441-54. [PMID: 673858 PMCID: PMC342175 DOI: 10.1093/nar/5.7.2441] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Interferon-pretreatment of vaccinia-infected chick embryo fibroblasts resulted in a greater than 50% decrease in ribose methylation of the penultimate "cap" nucleotide in virus-specific mRNA. However, in contrast to results obtained with cell-free systems, in intact infected cells there was (a) no detectable reduction in methylation of the 5'-ultimate m7G of viral mRNA; (b) a virus specificity of the interferon-induced change in mRNA "CAP"-methylation seems unlikely and (c) analysis of the ribosomal and transfer RNA fractions isolated from interferon-treated and control cells revealed identical patterns of methylated nucleotides. Thus, the interferon-induced change in methylation is specific for mRNA "CAPS".
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Chiang PK, Cantoni GL, Bader JP, Shannon WM, Thomas HJ, Montgomery JA. Adenosylhomocysteine hydrolase inhibitors: synthesis of 5'-deoxy-5'-(isobutylthio)-3-deazaadenosine and its effect on Rous sarcoma virus and Gross murine leukemia virus. Biochem Biophys Res Commun 1978; 82:417-23. [PMID: 208563 DOI: 10.1016/0006-291x(78)90892-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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17
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Hoffman J. Biosynthesis of S-N6-methyladenosylhomocysteine, an inhibitor of RNA methyltransferases. J Biol Chem 1978. [DOI: 10.1016/s0021-9258(17)40780-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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