TTP protects against acute liver failure by regulating CCL2 and CCL5 through m6A RNA methylation
Pingping Xiao, Mingxuan Li, Mengsi Zhou, Xuejun Zhao, Cheng Wang, Jinglin Qiu, Qian Fang, Hong Jiang, Huifen Dong, Rui Zhou
Pingping Xiao, Mingxuan Li, Mengsi Zhou, Xuejun Zhao, Cheng Wang, Jinglin Qiu, Qian Fang, Hong Jiang, Huifen Dong, Rui Zhou
View: Text | PDF
Research Article Hepatology Inflammation

TTP protects against acute liver failure by regulating CCL2 and CCL5 through m6A RNA methylation

Abstract

Tristetraprolin (TTP), an important immunosuppressive protein regulating mRNA decay through recognition of the AU-rich elements (AREs) within the 3′-UTRs of mRNAs, participates in the pathogenesis of liver diseases. However, whether TTP regulates mRNA stability through other mechanisms remains poorly understood. Here, we report that TTP was upregulated in acute liver failure (ALF), resulting in decreased mRNA stabilities of CCL2 and CCL5 through promotion of N6-methyladenosine (m6A) mRNA methylation. Overexpression of TTP could markedly ameliorate hepatic injury in vivo. TTP regulated the mRNA stabilization of CCL2 and CCL5. Interestingly, increased m6A methylation in CCL2 and CCL5 mRNAs promoted TTP-mediated RNA destabilization. Moreover, induction of TTP upregulated expression levels of WT1 associated protein, methyltransferase like 14, and YT521-B homology N6-methyladenosine RNA binding protein 2, which encode enzymes regulating m6A methylation, resulting in a global increase of m6A methylation and amelioration of liver injury due to enhanced degradation of CCL2 and CCL5. These findings suggest a potentially novel mechanism by which TTP modulates mRNA stabilities of CCL2 and CCL5 through m6A RNA methylation, which is involved in the pathogenesis of ALF.

Authors

Pingping Xiao, Mingxuan Li, Mengsi Zhou, Xuejun Zhao, Cheng Wang, Jinglin Qiu, Qian Fang, Hong Jiang, Huifen Dong, Rui Zhou

×

Figure 3

TTP mediates m6A RNA methylation level by regulating WTAP, METTL14, and YTHDF2.

Options: View larger image (or click on image) Download as PowerPoint
TTP mediates m6A RNA methylation level by regulating WTAP, METTL14, and ...
(A) Heatmap shows m6A-associated gene expression in TTP-knockdown cells. (B) Western blot for WTAP, METTL14, and YTHDF2 protein in TTP-knockdown cells. Graph shows protein levels ± SEM. (C) Dot blot was used to measure total m6A levels in TTP-knockdown or -overexpression cells. (D and E) Expression of WTAP, METTL14, and YTHDF2 protein was detected in injured liver after TTP-overexpression vector injection for 24 hours with immunohistochemistry (scale bar = 100 μm) and Western blot. Graph shows protein levels ± SEM (n = 6). (F and G) Expression of WTAP, METTL14, and YTHDF2 protein was detected in TTP deficiency mice liver induced by CCl4 (scale bar = 100 μm) and Western blot. Graph shows protein levels ± SEM (n = 5). (H) The level of m6A modification was measured in injured liver after TTP-overexpression vector injection. Methylene blue (MB) staining acted as the loading control for the dot blot. (I) The level of m6A modification was measured in TTP-knockdown mice induced by CCl4. Data represent mean ± SEM from 3 independent experiments. Statistics by 1-way ANOVA with Dunnett’s multiple comparisons test (B), 2-tailed Student’s t test (C, D, and F–I), and 2-way ANOVA with Tukey’s multiple comparisons test (E and H). *P < 0.05 versus Ctrl.