Emerging role of RNA acetylation modification ac4C in diseases: Current advances and future challenges

NAT10 mediated polycystic ovary syndrome through the ac4C modification of CXCL14

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder among women of reproductive age, underscoring the critical importance of investigating its regulatory mechanisms. N-Acetyltransferase 10 (NAT10) is a crucial enzyme involved in mRNA acetylation modification, mediating target genes expression through N4-acetylcytidine (ac4C) modification to regulate the biological function of various diseases. Nonetheless, the specific role of NAT10 in PCOS regulation remains undisclosed. Ac4C dot hybridization experiment was conducted to determine ac4C expression in PCOS tissues. RT-qPCR was employed to assess the expression levels of NAT10 and CXCL14 in PCOS tissues and KGN cells. Cells viability was assessed using the CCK-8 method, while cell proliferation capacity was evaluated through the colony formation assay and EDU assay. Flow cytometry analysis was utilized to measure the apoptosis rate. The ac4C modification level was determined by acrp-qPCR analysis. RIP and luciferase reporter experiments confirmed the target binding relationship. The rat experiments confirmed the specific regulatory role of NAT10 in polycystic ovary syndrome in vivo. This study highlighted reduced levels of NAT10 and ac4C in PCOS, where silencing NAT10 boosts KGN cell proliferation and suppresses apoptosis. Additionally, NAT10-mediated ac4C modification governed the chemokine CXCL14 expression. Our research unveiled that NAT10 modulated PCOS occurrence and progression by enhancing the CXCL14 mRNA stability through acetylation, presenting potential novel insights into the mechanisms of mRNA acetylation in PCOS.

NAT10 inhibits the pyroptosis of laryngeal squamous cell carcinoma through ac4C modification of ELANE mRNA

BACKGROUND

Laryngeal squamous cell carcinoma (LSCC) is the most common type of head and neck malignancy. NAT10 is a catalytic enzyme for ac4C and is involved in the progression of a variety of cancers. This study aimed to explore the effects and potential mechanisms of NAT10 in LSCC.

METHODS

Pyroptosis was assessed by measuring the release of lactic dehydrogenase, pyroptosis rate, and pyroptosis-related proteins. The RNA and protein levels were detected by quantitative real-time PCR and western blot, respectively. Potential mechanisms were validated using flow cytometry, ac4C dot blot, methylated RNA immunoprecipitation (MeRIP), RIP, and Dual-Luciferase Reporter Assay experiments.

RESULTS

The result showed that the levels of NAT10 in LSCC tissues and cells were elevated and positively correlated with tumor grading and clinical staging. Knockdown of NAT10 promoted the pyroptosis of LSCC cells. NAT10 directly interacted with ELANE, suppressed the stability of the ELANE mRNA. NAT10 inhibited pyroptosis in LSCC by downregulating the ELANE expression in vivo and in vitro.

CONCLUSION

NAT10 inhibited the pyroptosis of LSCC cells and contributed to LSCC progression by suppressing ELANE mRNA stability in ac4C modification manner, indicating that the NAT10-ac4C-ELANE axis might be a potential target for LSCC.

N4-acetylcytidine modification of LncRNA GFOD1-AS1 promotes high glucose-induced dysfunction in human dermal microvascular endothelial cells through stabilization of DNMT1 protein

Emerging evidence supports that angiogenesis is essential for the wound healing of diabetic foot ulcer (DFU), and high glucose (HG)-induced dysfunction of human dermal microvascular endothelial cells is a key factor that hinders angiogenesis. However, the underlying mechanisms by which HG leads to the dysfunction of human dermal microvascular endothelial cells has not been fully elucidated. In the present investigation, we discovered a significant upregulation of the long non-coding RNA GFOD1-AS1(GFOD1-AS1) in the ulcer margin samples of patients with DFU and the HG-induced dysfunction model of human dermal microvascular endothelial cells, attributing its dysregulation to the stabilizing effect of NAT10-mediated ac4C modification, as corroborated by an integrated approach of data mining and experimental validation. Subsequently, a series of in vitro functional analyses showed that ectopic expression of GFOD1-AS1 promoted impaired function of human dermal microvascular endothelial cells. In contrast, knockdown of GFOD1-AS1 significantly alleviated the HG-induced functional impairment in human dermal microvascular endothelial cells, as indicated by the enhanced cell proliferation, migration, and tube formation. Mechanistically, GFOD1-AS1 directly interacts with DNA methyltransferase DNMT1 to block its ubiquitin-proteasome degradation, thereby enhancing the protein stability of DNMT1.This stability elevates DNMT1 protein expression, ultimately inducing HG-induced dysfunction in human dermal microvascular endothelial cells. In summary, our results reveal that GFOD1-AS1 serves as a potential therapeutic target for DFU, and highlight the critical role of the NAT10/GFOD1-AS1/DNMT1 axis in the dysfunction of human dermal microvascular endothelial cells in DFU.

NAT10 Regulates LPS-Induced Inflammation via Stabilization of N4-Acetylated PTX3 mRNA in Human Dental Pulp Stem Cells

Severe dental pulp inflammation can lead to tissue lysis and destruction, underscoring the necessity for effective treatment of pulpitis. N-acetyltransferase 10 (NAT10)-mediated N4-acetylcytidine (ac4C) modification has recently emerged as a key regulator in inflammatory processes. However, whether NAT10 affects the inflammatory response in human dental pulp stem cells (hDPSCs) remains unelucidated. In this study, elevated NAT10 expression was observed in pulpitis tissues and LPS-stimulated hDPSCs. Knockdown of NAT10 led to reduced inflammatory gene expression and lower reactive oxygen species (ROS) production in LPS-stimulated hDPSCs, while the chemotactic migration of macrophages was also suppressed. Similar results were observed when hDPSCs were treated with Remodelin, an inhibitor of NAT10. Differentially expressed genes identified through RNA sequencing were significantly enriched in inflammatory signaling pathways after NAT10 depletion. Among the differential genes, pentraxins 3 (PTX3) was identified as the potential target gene due to the presence of the ac4C modification site and its known ability to regulate dental pulp inflammation. The mRNA and protein levels of PTX3 were reduced in NAT10-deficient cells, along with a decrease in its mRNA stability. Exogenous PTX3 supplementation partially reversed the inflammatory inhibition induced by NAT10 knockdown. Further evidence in vivo revealed that Remodelin treatment attenuated the severity of dental pulp inflammation in rats with pulpitis. In summary, these data indicated that NAT10 deficiency inhibited the stability of PTX3 mRNA and further inhibited hDPSC inflammation, while Remodelin might be a potential therapeutic agent for pulp capping.

NAT10 PROMOTES PYROPTOSIS AND PANCREATIC INJURY OF SEVERE ACUTE PANCREATITIS THROUGH AC4C MODIFICATION OF NLRP3

ABSTRACT

Severe acute pancreatitis (SAP) is a highly morbid acute digestive disorder linked to pyroptosis. N-acetyltransferase 10 (NAT10) facilitates the production of N4-acetylcytidine (ac4C) modifications in mRNA, thereby contributing to the progression of various diseases. However, the specific role of NAT10 in SAP remains to be elucidated. This study aimed to elucidate the mechanism through which NAT10 mediates pyroptosis in SAP. Sprague-Dawley rats and AR42J rat pancreatic exocrine cells were used to establish in vivo and in vitro models of SAP. The levels of ac4C and NAT10 expression were quantified using dot blot analysis and quantitative real-time PCR. Assessment of cell viability, apoptosis, amylase content, and concentrations of lactate dehydrogenase, IL-1β, and IL-18 was conducted to evaluate the severity of SAP both in vivo and in vitro . Pyroptosis was assessed by measuring caspase-1 and gasdermin D (GSDMD)-N-terminal (GSDMD-N) expression. Further mechanistic insights were gained using methylated RNA immunoprecipitation, RNA immunoprecipitation, and dual-luciferase reporter assays. Our findings indicate that the levels of ac4C modification and NAT10 were elevated in both in vivo and in vitro SAP models. Knockdown of NAT10 inhibited cell death and reduced the levels of amylase, lactate dehydrogenase, IL-1β, and IL-18 as well as the protein expression of caspase-1 and GSDMD-N, suggesting that NAT10 knockdown suppresses pyroptosis in SAP cell models. Mechanistically, NAT10 knockdown decreased the expression and stability of NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) mRNA by inhibiting ac4C modification of NLRP3. Moreover, NAT10 knockdown alleviated pancreatic tissue pathology, mitigated SAP severity, and suppressed pyroptosis in an SAP rat model. Collectively, these results demonstrate that NAT10 exacerbates pancreatic injury in SAP by promoting pyroptosis through ac4C modification of NLRP3, thereby enhancing its expression. These findings suggest a potential novel therapeutic target for SAP.

Nat10-mediated N4-acetylcytidine modification enhances Nfatc1 translation to exacerbate osteoclastogenesis in postmenopausal osteoporosis

Increased differentiation or activity of osteoclasts is the key pathogenic factor of postmenopausal osteoporosis (PMOP). N4-acetylcytidine (ac4C) modification, catalyzed by Nat10, is a novel posttranscriptional mRNA modification related to many diseases. However, its impact on regulating osteoclast activation in PMOP remains uncertain. Here, we initially observed that Nat10-mediated ac4C positively correlates with osteoclast differentiation of monocytes and low bone mass in PMOP. The specific knockout of Nat10 in monocytes and remodelin, a Nat10 inhibitor, alleviates ovariectomized (OVX)-induced bone loss by downregulating osteoclast differentiation. Mechanistically, epitranscriptomic analyses reveal that the nuclear factor of activated T cells cytoplasmic 1 (Nfatc1) is the key downstream target of ac4C modification during osteoclast differentiation. Subsequently, translatomic results demonstrate that Nat10-mediated ac4C enhances the translation efficiency (TE) of Nfatc1, thereby inducing Nfatc1 expression and consequent osteoclast maturation. Cumulatively, these findings reveal the promotive role of Nat10 in osteoclast differentiation and PMOP from a novel field of RNA modifications and suggest that Nat10 can be a target of epigenetic therapy for preventing bone loss in PMOP.

Stigmasterol alleviates endplate chondrocyte degeneration through inducing mitophagy by enhancing PINK1 mRNA acetylation via the ESR1/NAT10 axis

Intervertebral disc degeneration (IVDD) is a core factor in spinal degeneration. To date, there is no effective treatment for IVDD. It is urgent to identify the pathogenesis of IVDD to develop effective strategies for IVDD treatment. Alleviating endplate chondrocyte degeneration is a promising strategy for IVDD treatment, while mitophagy prevents degeneration of endplate chondrocytes. Stigmasterol (STM) protects neurons from injuries by triggering mitophagy, yet the effect of STM on the mitophagy of endplate chondrocytes in IVDD has not been reported. In this study, endplate chondrocyte degeneration was induced by interleukin-1β, and the ribonucleic acid (RNA) acetylation level was identified by acetylated RNA immunoprecipitation. Herein, results indicated that STM alleviated endplate chondrocyte degeneration. Besides, STM induced PTEN-induced kinase 1 (PINK1)-mediated mitophagy in degenerated endplate chondrocytes. Moreover, N-acetyltransferase 10 (NAT10) increased PINK1 expression by improving PINK1 mRNA acetylation in endplate chondrocytes. In addition, STM regulated NAT10 expression by estrogen receptor 1 (ESR1) in degenerated endplate chondrocytes. In summary, the present study revealed that STM attenuated endplate chondrocyte degeneration through inducing mitophagy by enhancing PINK1 mRNA acetylation via the ESR1/NAT10 axis. These findings would provide novel strategies for the treatment of IVDD.

Paeonol inhibits the Glycolysis in oral squamous cell carcinoma though suppressing NAT10-mediated ac4C modification

BACKGROUND

Oral squamous cell carcinoma (OSCC) is the most common malignant tumor of the oral and maxillofacial regions. Paeonol, derived from Moutan Cortex, has diverse pharmacological effects including anti-inflammatory and anticancer activities. The N-acetyltransferase 10 (NAT10)-mediated N4-acetylcytidine (ac4C) modification is a newly discovered RNA epigenetic mechanism. This study aimed to investigate the role of paeonol in OSCC and its underlying mechanisms of action.

METHODS

Cell viability and migration were assessed using a cell counting kit-8 and transwell migration assays. Glycolysis-related indices were detected using commercial kits. The interaction between NAT10 and hexokinase 2 (HK2) was examined using RNA immunoprecipitation and dual-luciferase reporter assays. A tumor-bearing mouse model was established.

RESULTS

The results showed that paeonol treatment decreased the viability, migration, and glycolysis of OSCC cells. Moreover, paeonol treatment inhibited NAT10-mediated ac4C modifications in OSCC cells. In addition, NAT10 overexpression upregulates glycolysis and cell migration in OSCC cells. Moreover, NAT10 upregulated ac4C levels of HK2 in OSCC cells. Animal studies have revealed that paeonol treatment decreases OSCC tumor growth.

CONCLUSION

This study revealed that paeonol inhibited glycolysis and cell migration in OSCC by suppressing the NAT10-mediated ac4C modification of HK2.

N4-acetylcytidine and other RNA modifications in epitranscriptome: insight into DNA repair and cancer development

N4-acetylcytidine (ac4C) is a post-transcriptional RNA modification that plays a crucial role in the epitranscriptome, influencing gene expression and cellular function. This modification occurs at the cytosine base, where an acetyl group is installed to the nitrogen at the 4th position (N4). This co-transcription modification affects RNA stability, RNA structure, and translation efficiency. Recent studies have uncovered a potential link between RNA modifications and DNA repair mechanisms, suggesting that ac4C-modified or methylated RNAs may interact with factors involved in DNA repair pathways; thus, influencing the cellular response to DNA damage. Dysregulation of modified RNAs, including ac4C RNA, has been implicated in cancer development, where aberrant levels of these RNAs may contribute to oncogenic transformation by altering genome stability and the expression of key genes regulating cell proliferation, cell cycle progression, and apoptosis. Understanding the dynamics of modified RNAs offers promising insights into the role of epitranscriptome in DNA repair processes and cancer treatment.

NAT10 promotes gastric cancer progression by enhancing the N4-acetylcytidine modification of TNC mRNA

BACKGROUND

Gastric cancer (GC) is a very aggressive malignant tumor of the digestive system. Previous studies have shown that N-acetyltransferase 10 (NAT10) can regulate the N4-acetylcytidine (ac4C) modification of downstream mRNAs through certain pathways to promote the progression of various tumors. However, reports on the regulatory effects of NAT10 on GC are rare. This study aimed to explore the potential mechanism by which NAT10 regulated GC progression.

METHODS

Clinical samples were used to study the correlation between NAT10 expression and poor prognosis in patients with GC by univariate analysis and multivariate analysis. In vitro and in vivo assays were performed to assess the effects of NAT10 and Tenascin C (TNC) on the malignant biological behaviors of GC cells. Acetylated RNA immunoprecipitation sequencing was conducted to explore the role of NAT10 in ac4C modification in GC. mRNA stability and translation efficiency assays were performed to investigate the effect of changes in NAT10 expression on its target TNC.

RESULTS

Analysis of clinical samples revealed that NAT10 expression was abnormally elevated and positively correlated with TNC expression in GC, and increased NAT10 expression led to poor overall survival. In vitro and in vivo experiments revealed that high NAT10 expression promoted the invasive and proliferative capacity of GC cells. Rescue experiments suggested that TNC played an important role in the above process. Mechanistically, the acetylation-based RNA immunoprecipitation sequencing and acetylated RNA immunoprecipitation qPCR results indicated that NAT10 regulated the level of ac4C modification by binding to specific regions in TNC mRNA, increasing mRNA stability and translation, upregulating TNC expression, further activating the TNC/Akt/TGF-β1 positive feedback loop.

CONCLUSIONS

In summary, our results reveal that NAT10 plays a critical role in GC development by affecting TNC mRNA stability and translation efficiency, which ultimately activates the TNC/Akt/TGF-β1 positive feedback loop. This study is expected to provide a novel target and theoretical basis for improving the diagnosis and treatment of GC.

N-acetyltransferase 10 impedes EZH2/H3K27me3/GABARAP axis mediated autophagy and facilitates lung cancer tumorigenesis through enhancing SGK2 mRNA acetylation

N4-acetylcytidine (ac4C) is a critical RNA modification implicated in cancer progression. Currently, N-acetyltransferase 10 (NAT10) is recognized as the sole "writer" protein responsible for ac4C modification. However, the study of NAT10 and ac4C modification in lung cancer remains sparse. In this study, we observed a significant upregulation of NAT10 expression in lung cancer, which is strongly correlated with poor prognostic outcomes. In vitro and in vivo experiments have demonstrated that NAT10 facilitates the proliferation, migration, and invasion of non-small cell lung cancer (NSCLC) cells while inhibiting autophagy flux. Mechanistically, NAT10 may enhance mRNA stability through ac4c modification at the 3' untranslated region (UTR) of SGK2 mRNA. Furthermore, SGK2 interacts with EZH2 and phosphorylates it at threonine 367, leading to increased protein stability of EZH2 and a reduction in its ubiquitination. Additionally, NAT10 impedes autophagy flux by preventing the fusion of autophagosomes with lysosomes and suppressing GABARAP transcription, which is regulated by EZH2-mediated H3K27me3. In summary, our study elucidates the biological significance and molecular mechanisms of the NAT10/SGK2/EZH2 axis in the pathogenesis of lung cancer, potentially providing novel prognostic markers and therapeutic targets for its treatment.

NAT10 promotes ovarian cancer cell migration, invasion, and stemness via N4-acetylcytidine modification of CAPRIN1

Ovarian cancer (OC) is the most lethal gynecological tumor. N4-acetylcytidine (ac4C) modification, catalyzed by the acetyltransferase NAT10, is involved in the occurrence and development of cancers. This study aimed to investigate the role of NAT10 in OC and the underlying molecular mechanisms. The expression of NAT10 and CAPRIN1 in OC cells lines were measured using quantitative real-time polymerase chain reaction and immunoblotting. Biological behaviors of OC cells were evaluated using EdU, Transwell, sphere formation, and immunoblotting assays. The molecular mechanism of NAT10 function was analyzed using bioinformatics, ac4C- RNA immunoprecipitation, and actinomycin D treatment assay. The effect of NAT10 on OC progression in vivo was evaluated using xenograft tumor model. The results indicated that NAT10 and CAPRIN1 were highly expressed in OC cells. NAT10 knockdown suppressed OC cell proliferation, migration, invasiveness, stemness, and epithelial-mesenchymal transition in vitro, and impeded tumor growth in vivo. Additionally, CAPRIN1 expression was found to be positively related to NAT10 expression in OC. Silencing of NAT10 inhibited ac4C levels of CAPRIN1 and reduced its RNA stability. Moreover, overexpression of CAPRIN1 reversed the suppression of migration, invasion, and stemness caused by NAT10 knockdown, while knockdown of CAPRIN1 alone inhibited these malignant behaviors of OC cells. In conclusion, NAT10 promotes OC progression by promoting cellular migration, invasion, and stemness via upregulating CAPRIN1 expression. Mechanistically, NAT10 stabilizes CAPRIN1 by promoting its ac4C modification. These findings suggest that NAT10 may be a promising therapy target for OC.

Epigenetic regulation of macrophage function in kidney disease: New perspective on the interaction between epigenetics and immune modulation

The interaction between renal intrinsic cells and macrophages plays a crucial role in the onset and progression of kidney diseases. In recent years, epigenetic mechanisms such as DNA methylation, histone modification, and non-coding RNA regulation have become essential windows for understanding these processes. This review focuses on how renal intrinsic cells (including tubular epithelial cells, podocytes, and endothelial cells), renal cancer cells, and mesenchymal stem cells influence the function and polarization status of macrophages through their own epigenetic alterations, and how the epigenetic regulation of macrophages themselves responds to kidney damage, thus participating in renal inflammation, fibrosis, and repair. Moreover, therapeutic studies targeting these epigenetic interaction mechanisms have found that the application of histone deacetylase inhibitors, histone methyltransferase inhibitors, various nanomaterials, and locked nucleic acids against non-coding RNA have positive effects on the treatment of multiple kidney diseases. This review summarizes the latest research advancements in these epigenetic regulatory mechanisms and therapies, providing a theoretical foundation for further elucidating the pathogenesis of kidney diseases and the development of novel therapeutic strategies.

Abnormal ac4C modification in metabolic dysfunction associated steatotic liver cells

The pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD) remains unclear due to the complexity of its etiology. The emerging field of the epitranscriptome has shown significant promise in advancing the understanding of disease pathogenesis and developing new therapeutic approaches. Recent research has demonstrated that N4-acetylcytosine (ac4C), an RNA modification within the epitranscriptome, is implicated in progression of various diseases. However, the role of ac4C modification in MASLD remains unexplored. Herein, we performed acRIP-ac4c-seq and RNA-seq analysis in free fatty acids-induced MASLD model cells, identifying 2128 differentially acetylated ac4C sites, with 1031 hyperacetylated and 1097 hypoacetylated peaks in MASLD model cells. Functional enrichments analysis showed that ac4C differentially modified genes were significantly involved in processes related to MASLD, such as nuclear transport and MAP kinase (MAPK) signaling pathway. We also identified 341 differentially expressed genes (DEGs), including 61 lncRNAs and 280 mRNAs, between control and MASLD model cells. Bioinformatics analysis showed that DEGs were significantly enriched in long-chain fatty acid biosynthetic process. Notably, 118 genes exhibited significant changes in both ac4C modification and expression levels in MASLD model cells. Among these proteins, JUN, caveolin-1 (CAV1), fatty acid synthase (FASN), and heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) were identified as core proteins through protein-protein interaction (PPI) network analysis using cytoscape software. Collectively, our findings establish a positive correlation between ac4C modification and the pathogenesis of MASLD and suggest that ac4C modification may serve as a therapeutic target for MASLD.

Peptidylprolyl isomerase D circular RNA sensitizes breast cancer to trastuzumab through remodeling HER2 N4-acetylcytidine modification

Human epidermal growth factor receptor 2 (HER2) overexpression and activation are crucial for trastuzumab resistance in HER2-positive breast cancer; however, the potential regulatory mechanism of HER2 is still largely undetermined. In this study, a novel circular RNA derived from peptidylprolyl isomerase D (PPID) is identified as a negative regulator of trastuzumab resistance. Circ-PPID is highly stable and significantly downregulated in trastuzumab-resistant cells and tissues. Restoration of circ-PPID markedly enhances HER2-positive breast cell sensitivity to trastuzumab in vitro and in vivo. Circ-PPID directly binds to N-acetyltransferase 10 (NAT10) in the nucleus and blocks the interaction between NAT10 and HER2 mRNA, reducing N4-acetylcytidine (ac4C) modification on HER2 exon 25, leading to HER2 mRNA decay. Intriguingly, the subcellular localization of circ-PPID differs between trastuzumab-sensitive and -resistant cells. Circ-PPID in trastuzumab-resistant cells is located more in the cytoplasm, mainly due to the upregulation of Exportin 4 (XPO4), which results in the loss of spatial conditions for circ-PPID to bind to nuclear NAT10. Taken together, our data suggest that circ-PPID is a previously unappreciated ac4C-dependent HER2 epigenetic regulator, providing a promising therapeutic direction for overcoming trastuzumab resistance in clinical setting.

The role and mechanism of NAT10-mediated ac4C modification in tumor development and progression

RNA modification has emerged as a crucial area of research in epigenetics, significantly influencing tumor biology by regulating RNA metabolism. N-acetyltransferase 10 (NAT10)-mediated N4-acetylcytidine (ac4C) modification, the sole known acetylation in eukaryotic RNA, influences cancer pathogenesis and progression. NAT10 is the only writer of ac4C and catalyzes acetyl transfer on targeted RNA, and ac4C helps to improve the stability and translational efficiency of ac4C-modified RNA. NAT10 is highly expressed and associated with poor prognosis in pan-cancers. Based on its molecular mechanism and biological functions, ac4C is a central factor in tumorigenesis, tumor progression, drug resistance, and tumor immune escape. Despite the increasing focus on ac4C, the specific regulatory mechanisms of ac4C in cancer remain elusive. The present review thoroughly analyzes the current knowledge on NAT10-mediated ac4C modification in cancer, highlighting its broad regulatory influence on targeted gene expression and tumor biology. This review also summarizes the limitations and perspectives of current research on NAT10 and ac4C in cancer, to identify new therapeutic targets and advance cancer treatment strategies.

NAT10 promotes liver lipogenesis in mouse through N4-acetylcytidine modification of Srebf1 and Scap mRNA

BACKGROUND

Metabolic dysfunction associated steatotic liver disease (MASLD), closely linked to excessive lipogenesis, induces chronic liver disease. MASLD often cause other metabolic diseases, such as cardiovascular disease, diabetes and obesity. However, the mechanism of N-acetyltransferase 10 (NAT10)-mediated N4-acetylcytidine (ac4C) mRNA modification in lipogenesis of MASLD has not been fully elucidated. This study investigated the role of NAT10 in lipogenesis targeting mRNA ac4C modification.

METHODS

The expression of NAT10 in mouse liver was assessed after a 12-week high-fat diet. In addition, the expression of NAT10 also was detected after AML12 hepatocytes cells were treated with 150 µmol/L palmitic acid (PA). The ac4C mRNA modification was performed by dot blotting. Oil red O staining and the mRNA expression of Srebf1, Acaca and Fasn were used to assess lipogenesis in AML12 cells with NAT10 overexpression or knockdown. acRIP-PCR and NAT10 RIP-PCR were used to verify the Srebf1 and Scap mRNA ac4C modification by NAT10. Furthermore, the liver lipogenesis was evaluated by AAV-mediated target knockdown of NAT10 in mouse liver and treating a specific inhibitor, Remodelin.

RESULTS

This study revealed that NAT10 is significantly upregulated in liver lipogenesis after a 12-week high-fat diet. NAT10 and ac4C mRNA modification were also drastically increased in AML12 cells after treated with 150 µmol/L PA. Silencing of NAT10 notably inhibited the lipogenesis in AML12 cells and AAV-mediated target knockdown of NAT10 in mouse liver. The acRIP-PCR and NAT10-RIP-PCR revealed that NAT10 ac4C modified Srebf1 and Scap mRNA, the critical modulator of liver lipogenesis, to regulate liver lipogenesis. Besides, Remodelin strongly inhibited liver lipogenesis, including liver TG, serum ALT, AST, TG and TC level and glucose metabolism.

CONCLUSIONS

NAT10 mediates ac4C modification of Srebf1 and Scap mRNA, thereby affecting lipogenesis in the liver. This study provided a new target for the treatment of MASLD.

Post-Translational Modifications of RNA-Modifying Proteins in Cellular Dynamics and Disease Progression

RNA-modifying proteins, classified as "writers," "erasers," and "readers," dynamically modulate RNA by adding, removing, or interpreting chemical groups, thereby influencing RNA stability, functionality, and interactions. To date, over 170 distinct RNA chemical modifications and more than 100 RNA-modifying enzymes have been identified, with ongoing research expanding these numbers. Although significant progress has been made in understanding RNA modification, the regulatory mechanisms that govern RNA-modifying proteins themselves remain insufficiently explored. Post-translational modifications (PTMs) such as phosphorylation, ubiquitination, and acetylation are crucial in modulating the function and behavior of these proteins. However, the full extent of PTM influence on RNA-modifying proteins and their role in disease development remains to be fully elucidated. This review addresses these gaps by offering a comprehensive analysis of the roles PTMs play in regulating RNA-modifying proteins. Mechanistic insights are provided into how these modifications alter biological processes, contribute to cellular function, and drive disease progression. In addition, the current research landscape is examined, highlighting the therapeutic potential of targeting PTMs on RNA-modifying proteins for precision medicine. By advancing understanding of these regulatory networks, this review seeks to facilitate the development of more effective therapeutic strategies and inspire future research in the critical area of PTMs in RNA-modifying proteins.

DPNN-ac4C: a dual-path neural network with self-attention mechanism for identification of N4-acetylcytidine (ac4C) in mRNA

MOTIVATION

The modification of N4-acetylcytidine (ac4C) in RNA is a conserved epigenetic mark that plays a crucial role in post-transcriptional regulation, mRNA stability, and translation efficiency. Traditional methods for detecting ac4C modifications are laborious and costly, necessitating the development of efficient computational approaches for accurate identification of ac4C sites in mRNA.

RESULTS

We present DPNN-ac4C, a dual-path neural network with a self-attention mechanism for the identification of ac4C sites in mRNA. Our model integrates embedding modules, bidirectional GRU networks, convolutional neural networks, and self-attention to capture both local and global features of RNA sequences. Extensive evaluations demonstrate that DPNN-ac4C outperforms existing models, achieving an AUROC of 91.03%, accuracy of 82.78%, MCC of 65.78%, and specificity of 84.78% on an independent test set. Moreover, DPNN-ac4C exhibits robustness under the Fast Gradient Method attack, maintaining a high level of accuracy in practical applications.

AVAILABILITY AND IMPLEMENTATION

The model code and dataset are publicly available on GitHub (https://github.com/shock1ng/DPNN-ac4C).

Loss of NAT10 Reduces the Translation of Kmt5a mRNA Through ac4C Modification in Cardiomyocytes and Induces Heart Failure

BACKGROUND

In the past decade, the biological functions of various RNA modifications in mammals have been uncovered. N4-acetylcytidine (ac4C), a highly conserved RNA modification, has been implicated in human diseases. Despite this, the involvement of RNA ac4C modification in cardiac physiology and pathology remains incompletely understood. NAT10 (N-acetyltransferase 10) stands as the sole acetyltransferase known to catalyze RNA ac4C modification. This study aims to explore the role of NAT10 and ac4C modification in cardiac physiology and pathology.

METHODS AND RESULTS

Cardiac-specific knockout of NAT10, leading to reduced RNA ac4C modification, during both neonatal and adult stages resulted in severe heart failure. NAT10 deficiency induced cardiomyocyte apoptosis, a crucial step in heart failure pathogenesis, supported by in vitro data. Activation of the p53 signaling pathway was closely associated with enhanced apoptosis in NAT10-deficient cardiomyocytes. As ac4C modification on mRNA influences translational efficiency, we employed ribosome footprints coupled with RNA sequencing to explore genome-wide translational efficiency changes caused by NAT10 deficiency. We identified and validated that the translational efficiency of Kmt5a was suppressed in NAT10 knockout hearts due to reduced ac4C modification on its mRNA. This finding was consistent with the observation that Kmt5a protein levels were reduced in heart failure despite unchanged mRNA expression. Knockdown of Kmt5a in cardiomyocytes recapitulated the phenotype of NAT10 deficiency, including increased cardiomyocyte apoptosis and activated p53 signaling. Finally, overexpression of Kmt5a rescued cardiomyocyte apoptosis and p53 activation induced by NAT10 inhibition.

CONCLUSIONS

Our study highlights the significance of NAT10 in cardiomyocyte physiology, demonstrating that NAT10 loss is sufficient to induce cardiomyocyte apoptosis and heart failure. NAT10 regulates the translational efficiency of Kmt5a, a key mediator, through mRNA ac4C modification during heart failure.

RNA ac4C modification in cancer: Unraveling multifaceted roles and promising therapeutic horizons

RNA modifications play a crucial role in cancer development, profoundly influencing various stages of the RNA lifecycle. These stages encompass nuclear processing, nuclear export, splicing, and translation in the cytoplasm. Among RNA modifications, RNA ac4C modification, also known as N4-acetylcytidine, stands out for its unique role in acetylation processes. Specific proteins regulate RNA ac4C modification, maintaining the dynamic and reversible nature of these changes. This review explores the molecular mechanisms and biological functions of RNA ac4C modification. It examines the intricate ways in which RNA ac4C modification influences the pathogenesis and progression of cancer. Additionally, the review provides an integrated overview of the current methodologies for detecting RNA ac4C modification. Exploring the potential applications of manipulating this modification suggests avenues for novel therapeutic strategies, potentially leading to more effective cancer treatments in the future.

The roles and mechanisms of coding and noncoding RNA variations in cancer

Functional variations in coding and noncoding RNAs are crucial in tumorigenesis, with cancer-specific alterations often resulting from chemical modifications and posttranscriptional processes mediated by enzymes. These RNA variations have been linked to tumor cell proliferation, growth, metastasis, and drug resistance and are valuable for identifying diagnostic or prognostic cancer biomarkers. The diversity of posttranscriptional RNA modifications, such as splicing, polyadenylation, methylation, and editing, is particularly significant due to their prevalence and impact on cancer progression. Additionally, other modifications, including RNA acetylation, circularization, miRNA isomerization, and pseudouridination, are recognized as key contributors to cancer development. Understanding the mechanisms underlying these RNA modifications in cancer can enhance our knowledge of cancer biology and facilitate the development of innovative therapeutic strategies. Targeting these RNA modifications and their regulatory enzymes may pave the way for novel RNA-based therapies, enabling tailored interventions for specific cancer subtypes. This review provides a comprehensive overview of the roles and mechanisms of various coding and noncoding RNA modifications in cancer progression and highlights recent advancements in RNA-based therapeutic applications.

Targeting N4-acetylcytidine suppresses hepatocellular carcinoma progression by repressing eEF2-mediated HMGB2 mRNA translation

BACKGROUND

N4-acetylcytidine (ac4C) represents a novel messenger RNA (mRNA) modification, and its associated acetyltransferase N-acetyltransferase 10 (NAT10) plays a crucial role in the initiation and progression of tumors by regulating mRNA functionality. However, its role in hepatocellular carcinoma (HCC) development and prognosis is largely unknown. This study aimed to elucidate the role of NAT10-mediated ac4C in HCC progression and provide a promising therapeutic approach.

METHODS

The ac4C levels were evaluated by dot blot and ultra-performance liquid chromatography-tandem mass spectrometry with harvested HCC tissues. The expression of NAT10 was investigated using quantitative real-time polymerase chain reaction, western blotting, and immunohistochemical staining across 91 cohorts of HCC patients. To explore the underlying mechanisms of NAT10-ac4C in HCC, we employed a comprehensive approach integrating acetylated RNA immunoprecipitation and sequencing, RNA sequencing and ribosome profiling analyses, along with RNA immunoprecipitation, RNA pull-down, mass spectrometry, and site-specific mutation analyses. The drug affinity responsive targets stability, cellular thermal shift assay, and surface plasmon resonance assays were performed to assess the specific binding of NAT10 and Panobinostat. Furthermore, the efficacy of targeting NAT10-ac4C for HCC treatment was elucidated through in vitro experiments using HCC cells and in vivo HCC mouse models.

RESULTS

Our investigation revealed a significant increase in both the ac4C RNA level and NAT10 expression in HCC. Notably, elevated NAT10 expression was associated with poor outcomes in HCC patients. Functionally, silencing NAT10 suppressed HCC proliferation and metastasis in vitro and in vivo. Mechanistically, NAT10 stimulates the ac4C modification within the coding sequence (CDS) of high mobility group protein B2 (HMGB2), which subsequently enhances HMGB2 translation by facilitating eukaryotic elongation factor 2 (eEF2) binding to the ac4C sites on HMGB2 mRNA's CDS. Additionally, high-throughput compound library screening revealed Panobinostat as a potent inhibitor of NAT10-mediated ac4C modification. This inhibition significantly attenuated HCC growth and metastasis in both in vitro experiments using HCC cells and in vivo HCC mouse models.

CONCLUSIONS

Our study identified a novel oncogenic epi-transcriptome axis involving NAT10-ac4C/eEF2-HMGB2, which plays a pivotal role in regulating HCC growth and metastasis. The drug Panobinostat validates the therapeutic potential of targeting this axis for HCC treatment.

NAT10 promotes synovial aggression by increasing the stability and translation of N4-acetylated PTX3 mRNA in rheumatoid arthritis

OBJECTIVE

Recent studies indicate that N-acetyltransferase 10 (NAT10)-mediated ac4C modification plays unique roles in tumour metastasis and immune infiltration. This study aimed to uncover the role of NAT10-mediated ac4C in fibroblast-like synoviocytes (FLSs) functions and synovial immune cell infiltration in rheumatoid arthritis (RA).

METHODS

FLSs were obtained from active established patients with RA. Protein expression was determined by western blotting or immunohistochemistry or multiplexed immunohistochemistry. Cell migration was measured using a Boyden chamber. ac4C-RIP-seq combined with RNA-seq was performed to identify potential targets of NAT10. RNA immunoprecipitation was used to validate the interaction between protein and mRNA. NAT10 haploinsufficiency, inhibitor remodelin or intra-articular Adv-NAT10 was used to suppress arthritis in mice with delayed-type hypersensitivity arthritis (DYHA) and collagen II-induced arthritis (CIA) and rats with CIA.

RESULTS

We found elevated levels of NAT10 and ac4C in FLSs and synovium from patients with RA. NAT10 knockdown or specific inhibitor treatment reduced the migration and invasion of RA FLSs. Increased NAT10 level in the synovium was positively correlated with synovial infiltration of multiple types of immune cells. NAT10 inhibition in vivo attenuated the severity of arthritis in mice with CIA and DTHA, and rats with CIA. Mechanistically, we explored that NAT10 regulated RA FLS functions by promoting stability and translation efficiency of N4-acetylated PTX3 mRNA. PTX3 also regulated RA FLS aggression and is associated with synovial immune cell infiltration.

CONCLUSION

Our findings uncover the important roles of NAT10-mediated ac4C modification in promoting rheumatoid synovial aggression and inflammation, indicating that NAT10 may be a potential target for the treatment of RA, even other dysregulated FLSs-associated disorders.

Mijiao formula regulates NAT10-mediated Runx2 mRNA ac4C modification to promote bone marrow mesenchymal stem cell osteogenic differentiation and improve osteoporosis in ovariectomized rats

ETHNOPHARMACOLOGICAL RELEVANCE

The Mijiao (MJ) formula, a traditional herbal remedy, incorporates antlers as its primary constituent. It can effectively treat osteoporosis (OP), anti-aging, enhance immune activity, and change depression-like behavior. In this study, we investigated that MJ formula is a comprehensive treatment strategy, and may provide a potential approach for the clinical treatment of postmenopausal osteoporosis.

AIM OF THE STUDY

The purpose of this study was to determine whether MJ formula promoted osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and improved osteoporosis in ovariectomized rats by regulating the NAT10-mediated Runx2 mRNA ac4C modification.

MATERIALS AND METHODS

Female Sprague-Dawley (SD) rats were used to investigate the potential therapeutic effect of MJ formula on OP by creating an ovariectomized (OVX) rat model. The expression of osteogenic differentiation related proteins in BMSCs was detected in vivo, indicating their role in promoting bone formation. In addition, the potential mechanism of its bone protective effect was explored via in vitro experiments.

RESULTS

Our study showed that MJ formula significantly mitigated bone mass loss in the OVX rat model, highlighting its potential as an OP therapeutic agent. We found that the possible mechanism of action was the ability of this formulation to stabilize Runx2 mRNA through NAT10-mediated ac4C acetylation, which promoted osteogenic differentiation of BMSCs and contributed to the enhancement of bone formation.

CONCLUSIONS

MJ formula can treat estrogen deficiency OP by stabilizing Runx2 mRNA, promoting osteogenic differentiation and protecting bone mass. Conceivably, MJ formulation could be a safe and promising strategy for the treatment of osteoporosis.

STM-ac4C: a hybrid model for identification of N4-acetylcytidine (ac4C) in human mRNA based on selective kernel convolution, temporal convolutional network, and multi-head self-attention

N4-acetylcysteine (ac4C) is a chemical modification in mRNAs that alters the structure and function of mRNA by adding an acetyl group to the N4 position of cytosine. Researchers have shown that ac4C is closely associated with the occurrence and development of various cancers. Therefore, accurate prediction of ac4C modification sites on human mRNA is crucial for revealing its role in diseases and developing new diagnostic and therapeutic strategies. However, existing deep learning models still have limitations in prediction accuracy and generalization ability, which restrict their effectiveness in handling complex biological sequence data. This paper introduces a deep learning-based model, STM-ac4C, for predicting ac4C modification sites on human mRNA. The model combines the advantages of selective kernel convolution, temporal convolutional networks, and multi-head self-attention mechanisms to effectively extract and integrate multi-level features of RNA sequences, thereby achieving high-precision prediction of ac4C sites. On the independent test dataset, STM-ac4C showed improvements of 1.81%, 3.5%, and 0.37% in accuracy, Matthews correlation coefficient, and area under the curve, respectively, compared to the existing state-of-the-art technologies. Moreover, its performance on additional balanced and imbalanced datasets also confirmed the model's robustness and generalization ability. Various experimental results indicate that STM-ac4C outperforms existing methods in predictive performance. In summary, STM-ac4C excels in predicting ac4C modification sites on human mRNA, providing a powerful new tool for a deeper understanding of the biological significance of mRNA modifications and cancer treatment. Additionally, the model reveals key sequence features that influence the prediction of ac4C sites through sequence region impact analysis, offering new perspectives for future research. The source code and experimental data are available at https://github.com/ymy12341/STM-ac4C.

ac4C: a fragile modification with stabilizing functions in RNA metabolism

In recent years, concerted efforts to map and understand epitranscriptomic modifications in mRNA have unveiled new complexities in the regulation of gene expression. These studies cumulatively point to diverse functions in mRNA metabolism, spanning pre-mRNA processing, mRNA degradation, and translation. However, this emerging landscape is not without its intricacies and sources of discrepancies. Disparities in detection methodologies, divergent interpretations of functional outcomes, and the complex nature of biological systems across different cell types pose significant challenges. With a focus of N4-acetylcytidine (ac4C), this review endeavors to unravel conflicting narratives by examining the technological, biological, and methodological factors that have contributed to discrepancies and thwarted research progress. Our goal is to mitigate detection inconsistencies and establish a unified model to elucidate the contribution of ac4C to mRNA metabolism and cellular equilibrium.

TransAC4C-a novel interpretable architecture for multi-species identification of N4-acetylcytidine sites in RNA with single-base resolution

N4-acetylcytidine (ac4C) is a modification found in ribonucleic acid (RNA) related to diseases. Expensive and labor-intensive methods hindered the exploration of ac4C mechanisms and the development of specific anti-ac4C drugs. Therefore, an advanced prediction model for ac4C in RNA is urgently needed. Despite the construction of various prediction models, several limitations exist: (1) insufficient resolution at base level for ac4C sites; (2) lack of information on species other than Homo sapiens; (3) lack of information on RNA other than mRNA; and (4) lack of interpretation for each prediction. In light of these limitations, we have reconstructed the previous benchmark dataset and introduced a new dataset including balanced RNA sequences from multiple species and RNA types, while also providing base-level resolution for ac4C sites. Additionally, we have proposed a novel transformer-based architecture and pipeline for predicting ac4C sites, allowing for highly accurate predictions, visually interpretable results and no restrictions on the length of input RNA sequences. Statistically, our work has improved the accuracy of predicting specific ac4C sites in multiple species from less than 40% to around 85%, achieving a high AUC > 0.9. These results significantly surpass the performance of all existing models.

Oligodeoxynucleotide Synthesis Under Non-Nucleophilic Deprotection Conditions

This protocol describes a method for the incorporation of sensitive functional groups into oligodeoxynucleotides (ODNs). The nucleophile-sensitive epigenetic N4-acetyldeoxycytosine (4acC) DNA modification is used as an example, but other sensitive groups can also be incorporated, e.g., alkyl halide, α-haloamide, alkyl ester, aryl ester, thioester, and chloropurine groups, all of which are unstable under the basic and nucleophilic deprotection and cleavage conditions used in standard ODN synthesis methods. The method uses a 1,3-dithian-2-yl-methoxycarbonyl (Dmoc) group that carries a methyl group at the carbon of the methoxy moiety (meDmoc) for the protection of exo-amines of nucleobases. The growing ODN is anchored to a solid support via a Dmoc linker. With these protecting and linking strategies, ODN deprotection and cleavage are achieved without using any strong bases and nucleophiles. Instead, they can be carried out under nearly neutral non-nucleophilic oxidative conditions. To increase the length of ODNs that can be synthesized using the meDmoc method, the protocol also describes the synthesis of a PEGylated Dmoc (pDmoc) phosphoramidite. With some of the nucleotides being incorporated with pDmoc-CE phosphoramidite, the growing ODN on the solid support carries PEG moieties and becomes more soluble, thus enabling longer ODN synthesis. The ODN synthesis method described in this protocol is expected to make many sensitive ODNs that are difficult to synthesize accessible to researchers in multiple areas, such as epigenetics, nanopore sequencing, nucleic acid-protein interactions, antisense drug development, DNA alkylation carcinogenesis, and DNA nanotechnology. © 2024 Wiley Periodicals LLC. Basic Protocol: Sensitive ODN synthesis Support Protocol 1: Synthesis of meDmoc-CE phosphoramidites Support Protocol 2: Synthesis of a pDmoc-CE phosphoramidite.

Deficiency of Acetyltransferase nat10 in Zebrafish Causes Developmental Defects in the Visual Function

Purpose

N4-acetylcytidine (ac4C) is a post-transcriptional RNA modification catalyzed by N-acetyltransferase 10 (NAT10), a critical factor known to influence mRNA stability. However, the role of ac4C in visual development remains unexplored.

Methods

Analysis of public datasets and immunohistochemical staining were conducted to assess the expression pattern of nat10 in zebrafish. We used CRISPR/Cas9 and RNAi technologies to knockout (KO) and knockdown (KD) nat10, the zebrafish ortholog of human NAT10, and evaluated its effects on early development. To assess the impact of nat10 knockdown on visual function, we performed comprehensive histological evaluations and behavioral analyses. Transcriptome profiling and real-time (RT)-PCR were utilized to detect alterations in gene expression resulting from the nat10 knockdown. Dot-blot and RNA immunoprecipitation (RIP)-PCR analyses were conducted to verify changes in ac4C levels in both total RNA and opsin mRNA specifically. Additionally, we used the actinomycin D assay to examine the stability of opsin mRNA following the nat10 KD.

Results

Our study found that the zebrafish NAT10 protein shares similar structural properties with its human counterpart. We observed that the nat10 gene was prominently expressed in the visual system during early zebrafish development. A deficiency of nat10 in zebrafish embryos resulted in increased mortality and developmental abnormalities. Behavioral and histological assessments indicated significant vision impairment in nat10 KD zebrafish. Transcriptomic analysis and RT-PCR identified substantial downregulation of retinal transcripts related to phototransduction, light response, photoreceptors, and visual perception in the nat10 KD group. Dot-blot and RIP-PCR analyses confirmed a pronounced reduction in ac4C levels in both total RNA and specifically in opsin messenger RNA (mRNA). Additionally, by evaluating mRNA decay in zebrafish treated with actinomycin D, we observed a significant decrease in the stability of opsin mRNA in the nat10 KD group.

Conclusions

The ac4C-mediated mRNA modification plays an essential role in maintaining visual development and retinal function. The loss of NAT10-mediated ac4C modification results in significant disruptions to these processes, underlining the importance of this RNA modification in ocular development.

NAT10 promotes renal ischemia-reperfusion injury via activating NCOA4-mediated ferroptosis

Ischemia-reperfusion injury (IRI) is a significant contributor to acute kidney injury (AKI) and is associated with substantial morbidity and mortality rates. In this study, we aimed to investigate the role of NAT10 and its ac4C RNA modification in IRI-induced renal injury. Our findings revealed that both the expression level of NAT10 and the RNA ac4C level in the kidneys were elevated in the IRI group compared to the sham group. Functionally, we observed that inhibition of NAT10 activity with Remodelin or the specific knockout of NAT10 in the kidney led to a significant attenuation of IRI-induced renal injury. Furthermore, in vitro experiments demonstrated that NAT10 inhibition and specific knockout of NAT10 in the kidney markedly suppressed global ac4C RNA modification, providing protection against hypoxia/reoxygenation-induced tubular epithelial cell injury and ferroptosis. Mechanistically, our study uncovered that NAT10 promoted ac4C RNA modification of NCOA4 mRNA, thereby enhancing its stability and contributing to IRI-induced ferroptosis in tubular epithelial cells (TECs). These findings underscore the potential of NAT10 and ac4C RNA modification as promising therapeutic targets for the treatment of AKI. Overall, our study sheds light on the critical involvement of NAT10 and ac4C RNA modification in the pathogenesis of IRI-induced renal injury, offering valuable insights for the development of novel AKI treatment strategies.

The mechanistic role of NAT10 in cancer: Unraveling the enigmatic web of oncogenic signaling

N-acetyltransferase 10 (NAT10), a versatile enzyme, has gained considerable attention as a significant player in the complex realm of cancer biology. Its enigmatic role in tumorigenesis extends across a wide array of cellular processes, impacting cell growth, differentiation, survival, and genomic stability. Within the intricate network of oncogenic signaling, NAT10 emerges as a crucial agent in multiple cancer types, such as breast, lung, colorectal, and leukemia. This compelling research addresses the intricate complexity of the mechanistic role of NAT10 in cancer development. By elucidating its active participation in essential physiological processes, we investigate the regulatory role of NAT10 in cell cycle checkpoints, coordination of chromatin remodeling, and detailed modulation of the delicate balance between apoptosis and cell survival. Perturbations in NAT10 expression and function have been linked to oncogenesis, metastasis, and drug resistance in a variety of cancer types. Furthermore, the bewildering interactions between NAT10 and key oncogenic factors, such as p53 and c-Myc, are deciphered, providing profound insights into the molecular underpinnings of cancer pathogenesis. Equally intriguing, the paradoxical role of NAT10 as a potential tumor suppressor or oncogene is influenced by context-dependent factors and the cellular microenvironment. This study explores the fascinating interplay of genetic changes, epigenetic changes, and post-translational modifications that shape the dual character of NAT10, revealing the delicate balance between cancer initiation and suppression. Taken together, this overview delves deeply into the enigmatic role of NAT10 in cancer, elucidating its multifaceted roles and its complex interplay with oncogenic networks.

The regulation of antiviral innate immunity through non-m6A RNA modifications

The post-transcriptional RNA modifications impact the dynamic regulation of gene expression in diverse biological and physiological processes. Host RNA modifications play an indispensable role in regulating innate immune responses against virus infection in mammals. Meanwhile, the viral RNAs can be deposited with RNA modifications to interfere with the host immune responses. The N6-methyladenosine (m6A) has boosted the recent emergence of RNA epigenetics, due to its high abundance and a transcriptome-wide widespread distribution in mammalian cells, proven to impact antiviral innate immunity. However, the other types of RNA modifications are also involved in regulating antiviral responses, and the functional roles of these non-m6A RNA modifications have not been comprehensively summarized. In this Review, we conclude the regulatory roles of 2'-O-methylation (Nm), 5-methylcytidine (m5C), adenosine-inosine editing (A-to-I editing), pseudouridine (Ψ), N1-methyladenosine (m1A), N7-methylguanosine (m7G), N6,2'-O-dimethyladenosine (m6Am), and N4-acetylcytidine (ac4C) in antiviral innate immunity. We provide a systematic introduction to the biogenesis and functions of these non-m6A RNA modifications in viral RNA, host RNA, and during virus-host interactions, emphasizing the biological functions of RNA modification regulators in antiviral responses. Furthermore, we discussed the recent research progress in the development of antiviral drugs through non-m6A RNA modifications. Collectively, this Review conveys knowledge and inspiration to researchers in multiple disciplines, highlighting the challenges and future directions in RNA epitranscriptome, immunology, and virology.

NAT10 regulates the repair of UVB-induced DNA damage and tumorigenicity

Chemical modifications in messenger RNA (mRNA) regulate gene expression and play critical roles in stress responses and diseases. Recently we have shown that N6-methyladenosine (m6A), the most abundant mRNA modification, promotes the repair of UVB-induced DNA damage by regulating global genome nucleotide excision repair (GG-NER). However, the roles of other mRNA modifications in the UVB-induced damage response remain understudied. N4-acetylcytidine (ac4C) is deposited in mRNA by the RNA-binding acetyltransferase NAT10. This NAT10-mediated ac4C in mRNA has been reported to increase both mRNA stability and translation. However, the role of ac4C and NAT10 in the UVB-induced DNA damage response remains poorly understood. Here we show that NAT10 plays a critical role in the repair of UVB-induced DNA damage lesions through regulating the expression of the key GG-NER gene DDB2. We found that knockdown of NAT10 enhanced the repair of UVB-induced DNA damage lesions by promoting the mRNA stability of DDB2. Our findings are in contrast to the previously reported role of NAT10-mediated ac4C deposition in promoting mRNA stability and may represent a novel mechanism for ac4C in the UVB damage response. Furthermore, NAT10 knockdown in skin cancer cells decreased skin cancer cell proliferation in vitro and tumorigenicity in vivo. Chronic UVB irradiation increases NAT10 protein levels in mouse skin. Taken together, our findings demonstrate a novel role for NAT10 in the repair of UVB-induced DNA damage products by decreasing the mRNA stability of DDB2 and suggest that NAT10 is a potential novel target for preventing and treating skin cancer.