N-acetyltransferase 10 regulates alphavirus replication via N4-acetylcytidine (ac4C) modification of the lymphocyte antigen six family member E (LY6E) mRNA.

Epitranscriptomic RNA modifications can regulate the stability of mRNA and affect cellular and viral RNA functions. The N4-acetylcytidine (ac4C) modification in the RNA viral genome was recently found to promote viral replication; however, the mechanism by which RNA acetylation in the host mRNA regulates viral replication remains unclear. To help elucidate this mechanism, the roles of N-acetyltransferase 10 (NAT10) and ac4C during the infection and replication processes of the alphavirus, Sindbis virus (SINV), were investigated. Cellular NAT10 was upregulated, and ac4C modifications were promoted after alphavirus infection, while the loss of NAT10 or inhibition of its N-acetyltransferase activity reduced alphavirus replication. The NAT10 enhanced alphavirus replication as it helped to maintain the stability of lymphocyte antigen six family member E mRNA, which is a multifunctional interferon-stimulated gene that promotes alphavirus replication. The ac4C modification was thus found to have a non-conventional role in the virus life cycle through regulating host mRNA stability instead of viral mRNA, and its inhibition could be a potential target in the development of new alphavirus antivirals.IMPORTANCEThe role of N4-acetylcytidine (ac4C) modification in host mRNA and virus replication is not yet fully understood. In this study, the role of ac4C in the regulation of Sindbis virus (SINV), a prototype alphavirus infection, was investigated. SINV infection results in increased levels of N-acetyltransferase 10 (NAT10) and increases the ac4C modification level of cellular RNA. The NAT10 was found to positively regulate SINV infection in an N-acetyltransferase activity-dependent manner. Mechanistically, the NAT10 modifies lymphocyte antigen six family member E (LY6E) mRNA-the ac4C modification site within the 3'-untranslated region (UTR) of LY6E mRNA, which is essential for its translation and stability. The findings of this study demonstrate that NAT10 regulated mRNA stability and translation efficiency not only through the 5'-UTR or coding sequence but also via the 3'-UTR region. The ac4C modification of host mRNA stability instead of viral mRNA impacting the viral life cycle was thus identified, indicating that the inhibition of ac4C could be a potential target when developing alphavirus antivirals.

N-acetyltransferase 10 promotes the progression of oral squamous cell carcinoma through N4-acetylcytidine RNA acetylation of MMP1 mRNA.

The pathogenesis of oral squamous cell carcinoma (OSCC) remains unclear. Therefore, clarifying its pathogenesis and molecular-level development mechanism has become the focus of OSCC research. N-acetyltransferase 10 (NAT10) is a crucial enzyme involved in mRNA acetylation, regulating target gene expression and biological functions of various diseases through mediating N4-acetylcytidine (ac4C) acetylation. However, its role in OSCC progression is not well understood. In this study, we showed that NAT10 was significantly upregulated in OSCC tissues compared to normal oral tissues. Moreover, lentivirus-mediated NAT10 knockdown markedly suppressed cell proliferation, migration, and invasion in two OSCC cell lines (SCC-9 and SCC-15). Interestingly, MMP1 was found to be significantly upregulated in OSCC tissues and was a potential target of NAT10. N-acetyltransferase 10 knockdown significantly reduced both the total and ac4C acetylated levels of MMP1 mRNA and decreased its mRNA stability. Xenograft experiments further confirmed the inhibitory effect of NAT10 knockdown on the tumorigenesis and metastasis ability of OSCC cells and decreased MMP1 expression in vivo. Additionally, NAT10 knockdown impaired the proliferation, migration, and invasion abilities in OSCC cell lines in an MMP1-dependent manner. Our results suggest that NAT10 acts as an oncogene in OSCC, and targeting ac4C acetylation could be a promising therapeutic strategy for OSCC treatment.

tRNA-derived small RNA (tsr007330) regulates myocardial fibrosis after myocardial infarction through NAT10-mediated ac4C acetylation of EGR3 mRNA.

Small non-coding ribonucleic acids (sncRNAs) play an important role in cell regulation and are closely related to the pathogenesis of heart diseases. However, the role and molecular mechanism of transfer RNA-derived small RNAs (tsRNAs) in myocardial fibrosis after myocardial infarction (MI) remain unknown. In this study, we identified and validated sncRNAs (mainly miRNA and tsRNA) associated with myocardial fibrosis after MI through PANDORA sequencing of rat myocardial tissue. As a key enzyme of N4-acetylcytidine (ac4C) acetylation modification, N-acetyltransferase 10 (NAT10) plays an important role in regulating messenger RNA (mRNA) stability and translation efficiency. We found that NAT10 is highly expressed in infarcted myocardial tissue, and the results of acetylated RNA immunoprecipitation sequencing (acRIP-seq) analysis suggest that early growth response 3 (EGR3) may be an important molecule in the pathogenesis of NAT10-mediated myocardial fibrosis. Both in vivo and in vitro experiments have shown that inhibition of NAT10 can reduce the expression of EGR3 and alleviate myocardial fibrosis after MI. tsRNA can participate in gene regulation by inhibiting target genes. The expression of tsr007330 was decreased in myocardial infarction tissue. We found that overexpression of tsr007330 in rat myocardial tissue could antagonize NAT10, improve myocardial function in MI and alleviate myocardial fibrosis. In conclusion, tsRNAs (rno-tsr007330) may regulate the occurrence of myocardial fibrosis by regulating NAT10-mediated EGR3 mRNA acetylation. This study provides new insights into the improvement of myocardial fibrosis after MI by targeting tsRNA therapy.

N-acetyltransferase 10 promotes colon cancer progression by inhibiting ferroptosis through N4-acetylation and stabilization of ferroptosis suppressor protein 1 (FSP1) mRNA.

BACKGROUND: N-acetyltransferase 10 (NAT10) is the only enzyme known to mediate the N4-acetylcytidine (ac4C) modification of mRNA and is crucial for mRNA stability and translation efficiency. However, its role in cancer development and prognosis has not yet been explored. This study aimed to examine the possible role of NAT10 in colon cancer. METHODS: The expression levels of NAT10 were evaluated by immunohistochemical analyses with a colon cancer tissue microarray, and its prognostic value in patients was further analyzed. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were performed to analyze NAT10 expression in harvested colon cancer tissues and cell lines. Stable NAT10-knockdown and NAT10-overexpressing colon cancer cell lines were constructed using lentivirus. The biological functions of NAT10 in colon cancer cell lines were analyzed in vitro by Cell Counting Kit-8 (CCK-8), wound healing, Transwell, cell cycle, and ferroptosis assays. Xenograft models were used to analyze the effect of NAT10 on the tumorigenesis and metastasis of colon cancer cells in vivo. Dot blotting, acetylated RNA immunoprecipitation-qPCR, and RNA stability analyses were performed to explore the mechanism by which NAT10 functions in colon cancer progression. RESULTS: NAT10 was upregulated in colon cancer tissues and various colon cancer cell lines. This increased NAT10 expression was associated with shorter patient survival. Knockdown of NAT10 in two colon cancer cell lines (HT-29 and LoVo) impaired the proliferation, migration, invasion, tumor formation and metastasis of these cells, whereas overexpression of NAT10 promoted these abilities. Further analysis revealed that NAT10 exerted a strong effect on the mRNA stability and expression of ferroptosis suppressor protein 1 (FSP1) in HT-29 and LoVo cells. In these cells, FSP1 mRNA was found to be modified by ac4C acetylation, and this epigenetic modification was associated with the inhibition of ferroptosis. CONCLUSIONS: Our study revealed that NAT10 plays a critical role in colon cancer development by affecting FSP1 mRNA stability and ferroptosis, suggesting that NAT10 could be a novel prognostic and therapeutic target in colon cancer.