PIWI-Interacting RNA HAAPIR Regulates Cardiomyocyte Death After Myocardial Infarction by Promoting NAT10-Mediated ac4 C Acetylation of Tfec mRNA

Research progress of non-coding RNA regulating the role of PANoptosis in diabetes mellitus and its complications

Diabetes is a chronic metabolic disease that is endemic worldwide and is characterized by persistent hyperglycemia accompanied by multiple severe complications, including cardiovascular disease, kidney dysfunction, neuropathy, and retinopathy. The pathogenesis of diabetes mellitus and its complications is multifactorial, involving various molecular and cellular pathways. In recent years, research has indicated that mechanisms of cell death play a significant role in the advancement of diabetes and its complications. PANoptosis is a complex phenomenon caused by three cell death pathways: programmed apoptosis, necroptosis and pyroptosis. The contribution of PANoptosis to diabetes and its complications remains incompletely understood. Non-coding RNA, an important molecule in gene expression regulation, has shown significant regulatory functions in a variety of diseases. This paper reviews the underlying mechanisms of diverse types of non-coding RNAs (including lncRNA, miRNA and circRNA) in regulating PANoptosis and their specific contributions in diabetes, aiming to explore how non-coding RNAs influence PANoptosis and their effects in diabetes.

Advances of NAT10 in diseases: insights from dual properties as protein and RNA acetyltransferase

N-acetyltransferase 10 (NAT10) is a member of the Gcn5-related N-acetyltransferase (GNAT) family and it plays a crucial role in various cellular processes, such as regulation of cell mitosis, post-DNA damage response, autophagy and apoptosis regulation, ribosome biogenesis, RNA modification, and other related pathways through its intrinsic protein acetyltransferase and RNA acetyltransferase activities. Moreover, NAT10 is closely associated with the pathogenesis of tumors, Hutchinson-Gilford progeria syndrome (HGPS), systemic lupus erythematosus, pulmonary fibrosis, depression and host-pathogen interactions. In recent years, mRNA acetylation has emerged as a prominent focus of research due to its pivotal role in regulating RNA stability and translation. NAT10 stands out as the sole identified modification enzyme responsible for RNA acetylation. There remains some ambiguity regarding the similarities and differences in NAT10's actions on protein and RNA substrates. While NAT10 involves acetylation modification in both cases, which is a crucial molecular mechanism in epigenetic regulation, there are significant disparities in the catalytic mechanisms, regulatory pathways, and biological processes involved. Therefore, this review aims to offer a comprehensive overview of NAT10 as a protein and RNA acetyltransferase, covering its basic catalytic features, biological functions, and roles in related diseases.

Compression force promotes the osteogenic differentiation of periodontal ligament stem cells by regulating NAT10-mediated ac4C modification of BMP2

BACKGROUND

Orthodontic treatment applies specific corrective forces to teeth, transmitting stress to periodontal tissue, thereby regulating the growth and development of periodontal ligament stem cells (PDLSCs). Recently, N-acetyltransferase 10 (NAT10) mediated N4-acetylcytidine (ac4C) modification is demonstrated to play a key role in the osteogenic differentiation of stem cells. Therefore, this study aimed explore the effects of Orthodontic treatment on the NAT10 mediated ac4C modification and osteogenic differentiation of PDLSCs.

METHODS

Compressive force was used to treat PDLSCs to simulate orthodontic force treatment. The ALP and ARS staining was performed to analyze the osteogenic differentiation of PDLSCs. Besides, ac4C dot blot and ac4C-RIP assays were performed to detect the global ac4C levels and BMP2 ac4C levels. The relationship between NAT10 and BMP2 was confirmed by RIP assay and immunofluorescence staining. The mRNA and protein levels of RUNX2, Oxterix and BMP2 were detected by RT-qPCR and western blot assays.

RESULTS

Compressive force treatment promoted the osteogenic differentiation of PDLSCs, and enhanced the global ac4C levels and NAT10 levels in PDLSCs. NAT10 overexpression further promoted the osteogenic differentiation of compressive force treated PDLSCs. Besides, NAT10 overexpression increased ac4C levels of BMP2 and enhanced the mRNA stability of BMP2. Remodelin treatment significantly decreased the ac4C and mRNA levels of BMP2. Furthermore, BMP2 silencing reversed the role of NAT10 in the compressive force treated PDLSCs.

CONCLUSION

This study demonstrated that compressive force promotes cell viability and osteogenic differentiation of PDLSCs by regulating BMP2 levels mediated by NAT10. NAT10 mediated ac4C levels of BMP2 is the key signaling axis of orthodontic stress in promoting cell growth and osteogenic differentiation of PDLSCs.

Inhibition of Hsp90 K284 Acetylation Aalleviates Cardiac Injury After Ischemia-Reperfusion Injury

Our objective was to determine the role of acetyl-Hsp90 and its relationship with the NF-κB p65 signaling pathway in CVDs. We investigated the effect of acetyl-Hsp90 on cardiac inflammation and apoptosis after ischemia-reperfusion injury (I/RI). The results showed that the induction of acetyl-Hsp90 occurred in the heart during I/R and in primary cardiomyocytes during oxygen-glucose deprivation/reoxygenation (OGD/R). Moreover, the nonacetylated mutant of Hsp90 (Hsp90-K284R), through the regulation of ATPase activities within its N-terminal domain (NTD), indirectly or directly increases its interaction with NF-κB p65. This led to a reduction in the activation of the NF-κB p65 pathway, thereby attenuating inflammation, apoptosis, and fibrosis, ultimately leading to an improvement in cardiac function. Furthermore, we demonstrated that recombinant human interleukin-37 (rIL-37) exerts a similar cardioprotective effect by reducing acetylation at K284 of Hsp90 after inhibiting the expression of KAT2A.

The tRNA methyltransferase Mettl1 governs ketogenesis through translational regulation and drives metabolic reprogramming in cardiomyocyte maturation

After birth, the heart undergoes a shift in energy metabolism and cytoarchitecture to enhance efficient energy production and cardiac contraction, which is essential for postnatal development and growth. However, the precise mechanisms regulating this process remain elusive. Here we show that the RNA modification enzyme Mettl1 is a critical regulator of postnatal metabolic reprogramming and cardiomyocyte maturation in mice, primarily through its influence on the translation of the rate-limiting ketogenesis enzyme Hmgcs2. Our findings reveal that ketogenesis is vital for the postnatal transition of fuel from glucose to fatty acids in cardiomyocytes, achieved by modulating tricarboxylic acid cycle-related enzymatic activity via lysine β-hydroxybutyrylation protein modification. Loss of Mettl1 results in aberrant metabolic reprogramming and cardiomyocyte immaturity, leading to heart failure, although some clinical features can be rescued by β-hydroxybutyrate supplementation. Our study provides mechanistic insights into how Mettl1 regulates metabolic reprogramming in neonatal cardiomyocytes and highlights the importance of ketogenesis in cardiomyocyte maturation.

NAT10-mediated RNA ac4C acetylation contributes to the myocardial infarction-induced cardiac fibrosis

Cardiac fibrosis is featured cardiac fibroblast activation and extracellular matrix accumulation. Ac4C acetylation is an important epigenetic regulation of RNAs that has been recently discovered, and it is solely carried out by NAT10, the exclusive enzyme used for the modification. However, the potential regulatory mechanisms of ac4C acetylation in myocardial fibrosis following myocardial infarction remain poorly understood. In our study, we activated fibroblasts in vitro using TGF-β1 (20 ng/mL), followed by establishing a myocardial infarction mouse model to evaluate the impact of NAT10 on collagen synthesis and cardiac fibroblast proliferation. We utilized a NAT10 inhibitor, Remodelin, to attenuate the acetylation capacity of NAT10. In the cardiac fibrosis tissues of chronic myocardial infarction mice and cultured cardiac fibroblasts (CFs) in response to TGF-β1 treatment, there was an elevation in the levels of NAT10 expression. This increase facilitated proliferation, the accumulation of collagens, as well as fibroblast-to-myofibroblast transition. Through the administration of Remodelin, we effectively reduced cardiac fibrosis in myocardial infarction mice by inhibiting NAT10's ability to acetylate mRNA. Inhibition of NAT10 resulted in changes in collagen-related gene expression and ac4C acetylation levels. Mechanistically, we found that NAT10 upregulates the acetylation modification of BCL-XL mRNA and enhances the stability of BCL-XL mRNA, thereby upregulating its protein expression, inhibiting the activation of Caspase3 and blocking the apoptosis of CFs. Therefore, the crucial involvement of NAT10-mediated ac4C acetylation is significant in the cardiac fibrosis progression, affording promising molecular targets for the treatment of fibrosis and relevant cardiac diseases.

NAT10 promotes vascular remodelling via mRNA ac4C acetylation

BACKGROUND AND AIMS

Vascular smooth muscle cell (VSMC) phenotype switching is a pathological hallmark in various cardiovascular diseases. N4-acetylcytidine (ac4C) catalyzed by N-acetyltransferase 10 (NAT10) is well conserved in the enzymatic modification of ribonucleic acid (RNA). NAT10-mediated ac4C acetylation is involved in various physiological and pathological processes, including cardiac remodelling. However, the biological functions and underlying regulatory mechanisms of mRNA ac4C modifications in vascular diseases remain elusive.

METHODS

By combining in-vitro and in-vivo vascular injury models, NAT10 was identified as a crucial protein involved in the promotion of post-injury neointima formation, as well as VSMC phenotype switching. The potential mechanisms of NAT10 in the vascular neointima formation were clarified by RNA sequence (RNA-seq), acetylated mRNA immunoprecipitation sequence (acRIP-seq), and RNA binding protein immunoprecipitation sequence (RIP-seq).

RESULTS

NAT10 and ac4C modifications were upregulated in injured human and rodent arteries. Deletion of NAT10 in VSMCs effectively reduced post-injury neointima formation and VSMC phenotype switching. Further RNA-seq, RIP-seq, and acRIP-seq revealed that NAT10, by its ac4C modification, directly interacts with genes, including integrin-β1 (ITGB1) and collagen type I alpha 2 chain (Col1a2) mRNAs. Taking ITGB1 as one example, it showed that NAT10-mediated ac4C consequently increased ITGB1 mRNA stability and its downstream focal adhesion kinase (FAK) signaling, directly influencing the proliferation of VSMCs and vascular remodelling. The regulation of NAT10 on the VSMC phenotype is of translational significance because the administration of Remodelin, a NAT10 inhibitor, effectively prevents neointima formation by suppressing VSMC proliferation and downregulating ITGB1 expression and deactivating its FAK signaling.

CONCLUSIONS

This study reveals that NAT10 promotes vascular remodelling via mRNA ac4C acetylation, which may be a promising therapeutic target against vascular remodelling.

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.

Epigenetic regulation of diverse regulated cell death modalities in cardiovascular disease: Insights into necroptosis, pyroptosis, ferroptosis, and cuproptosis

Cell death constitutes a critical component of the pathophysiology of cardiovascular diseases. A growing array of non-apoptotic forms of regulated cell death (RCD)-such as necroptosis, ferroptosis, pyroptosis, and cuproptosis-has been identified and is intimately linked to various cardiovascular conditions. These forms of RCD are governed by genetically programmed mechanisms within the cell, with epigenetic modifications being a common and crucial regulatory method. Such modifications include DNA methylation, RNA methylation, histone methylation, histone acetylation, and non-coding RNAs. This review recaps the roles of DNA methylation, RNA methylation, histone modifications, and non-coding RNAs in cardiovascular diseases, as well as the mechanisms by which epigenetic modifications regulate key proteins involved in cell death. Furthermore, we systematically catalog the existing epigenetic pharmacological agents targeting novel forms of RCD and their mechanisms of action in cardiovascular diseases. This article aims to underscore the pivotal role of epigenetic modifications in precisely regulating specific pathways of novel RCD in cardiovascular diseases, thus offering potential new therapeutic avenues that may prove more effective and safer than traditional treatments.

Epigenetic regulation of sex dimorphism in cardiovascular health

Cardiovascular diseases (CVDs) remain the leading cause of morbidity and mortality, affecting people of all races, ages, and sexes. Substantial sex dimorphism exists in the prevalence, manifestation, and outcomes of CVDs. Understanding the role of sex hormones as well as sex-hormone-independent epigenetic mechanisms could play a crucial role in developing effective and sex-specific cardiovascular therapeutics. Existing research highlights significant disparities in sex hormones, epigenetic regulators, and gene expression related to cardiac health, emphasizing the need for a nuanced understanding of these variations between men and women. Despite these differences, current treatment approaches for CVDs often lack sex-specific considerations. A pivotal shift toward personalized medicine, informed by comprehensive insights into sex-specific DNA methylation, histone modifications, and non-coding RNA dynamics, holds the potential to revolutionize CVD management. By understanding sex-specific epigenetic complexities, independent of sex hormone influence, future cardiovascular research can be tailored to achieve effective diagnostic and therapeutic interventions for both men and women. This review summarizes the current knowledge and gaps in epigenetic mechanisms and sex dimorphism implicated in CVDs.

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.

The potential of RNA methylation in the treatment of cardiovascular diseases

RNA methylation has emerged as a dynamic regulatory mechanism that impacts gene expression and protein synthesis. Among the known RNA methylation modifications, N6-methyladenosine (m6A), 5-methylcytosine (m5C), 3-methylcytosine (m3C), and N7-methylguanosine (m7G) have been studied extensively. In particular, m6A is the most abundant RNA modification and has attracted significant attention due to its potential effect on multiple biological processes. Recent studies have demonstrated that RNA methylation plays an important role in the development and progression of cardiovascular disease (CVD). To identify key pathogenic genes of CVD and potential therapeutic targets, we reviewed several common RNA methylation and summarized the research progress of RNA methylation in diverse CVDs, intending to inspire effective treatment strategies.

piR-27222 mediates PM2.5-induced lung cancer by resisting cell PANoptosis through the WTAP/m6A axis

PM2.5 pollution has been associated with the incidence of lung cancer, but the underlying mechanism is still unclear. PIWI-interacting RNAs (piRNAs), initially identified in germline cells, have emerged as a novel class of small non-coding RNAs (26 - 32 nucleotides) with diverse functions in various diseases, including cancer. However, the role and mechanism of piRNAs in the development of PM2.5-induced lung cancer remain to be clarified. In the presented study, we used a PM2.5-induced malignant transformation cell model to analyze the change of piRNA profiles. Among the disturbed piRNAs, piR-27222 was identified as an oncogene that inhibited cell death in a m6A-dependent manner. Mechanistically, we found that piR-27222 could deubiquitinate and stabilize eIF4B by directly binding to eIF4B and reducing its interaction with PARK2. The enhanced expression of eIF4B, in turn, promoted the expression of WTAP, leading to increased m6A modification in the Casp8 transcript. Consequently, the stability of Casp8 transcripts was reduced, rendering lung cancer cells resistant to PANoptosis. Collectively, our findings reveal that PM2.5 exposure up-regulated piR-27222 expression, which could affect EIF4B/WTAP/m6A axis, thereby inhibiting PANoptosis of cells and promoting lung cancer. Our study provides new insights into understanding the epigenetic mechanisms underlining PM2.5-induced lung cancer.

Recent advances of PIWI-interacting RNA in cardiovascular diseases

BACKGROUND

The relationship between noncoding RNAs (ncRNAs) and human diseases has been a hot topic of research, but the study of ncRNAs in cardiovascular diseases (CVDs) is still in its infancy. PIWI-interacting RNA (piRNA), a small ncRNA that binds to the PIWI protein to maintain genome stability by silencing transposons, was widely studied in germ lines and stem cells. In recent years, piRNA has been shown to be involved in key events of multiple CVDs through various epigenetic modifications, revealing the potential value of piRNA as a new biomarker or therapeutic target.

CONCLUSION

This review explores origin, degradation, function, mechanism and important role of piRNA in CVDs, and the promising therapeutic targets of piRNA were summarized. This review provide a new strategy for the treatment of CVDs and lay a theoretical foundation for future research.

KEY POINTS

piRNA can be used as a potential therapeutic target and biomaker in CVDs. piRNA influences apoptosis, inflammation and angiogenesis by regulating epigenetic modificaions. Critical knowledge gaps remain in the unifying piRNA nomenclature and PIWI-independent function.

Oral Piwi-Interacting RNA Delivery Mediated by Green Tea-Derived Exosome-Like Nanovesicles for the Treatment of Aortic Dissection

Aortic dissection (AD) is a severe cardiovascular disease necessitating active therapeutic strategies for early intervention and prevention. Nucleic acid drugs, known for their potent molecule-targeting therapeutic properties, offer potential for genetic suppression of AD. Piwi-interacting RNAs, a class of small RNAs, hold promise for managing cardiovascular diseases. Limited research on these RNAs and AD exists. This study demonstrates that an antagomir targeting heart-apoptosis-associated piRNA (HAAPIR) effectively regulates vascular remodeling, mitigating AD occurrence and progression through the myocyte enhancer factor 2D (Mef2D) and matrix metallopeptidase 9 (MMP9) pathways. Green tea-derived plant exosome-like nanovesicles (PELNs) are used for oral administration of antagomir. The antagomir-HAAPIR-nanovesicle complex, after purification and optimization, exhibits a high packing rate, while the antagomir is resistant to enzyme digestion. Administered to mice, the complex targets the aortic lesion, reducing AD incidence and improving survival. Moreover, MMP9 and Mef2D expression decrease significantly, inhibiting the phenotypic conversion of human aortic smooth muscle cells. PELNs encapsulate the antagomir-HAAPIR complex, maintaining stability, mediating transport into the bloodstream, and delivering Piwi-interacting RNAs to AD sites. Thus, HAAPIR is a potential target for persistent clinical AD prevention and treatment, and nanovesicle-encapsulated nucleic acids offer a promising cardiovascular disease treatment, providing insights for other therapeutic targets.

piRNA associates with immune diseases

PIWI-interacting RNA (piRNA) is the most abundant small non-coding RNA in animal cells, typically 26-31 nucleotides in length and it binds with PIWI proteins, a subfamily of Argonaute proteins. Initially discovered in germ cells, piRNA is well known for its role in silencing transposons and maintaining genome integrity. However, piRNA is also present in somatic cells as well as in extracellular vesicles and exosomes. While piRNA has been extensively studied in various diseases, particular cancer, its function in immune diseases remains unclear. In this review, we summarize current research on piRNA in immune diseases. We first introduce the basic characteristics, biogenesis and functions of piRNA. Then, we review the association of piRNA with different types of immune diseases, including autoimmune diseases, immunodeficiency diseases, infectious diseases, and other immune-related diseases. piRNA is considered a promising biomarker for diseases, highlighting the need for further research into its potential mechanisms in disease pathogenesis.

Potential molecular mechanisms and clinical implications of piRNAs in preeclampsia: a review

Preeclampsia is a multisystem progressive condition and is one of the most serious complications of pregnancy. Owing to its unclear pathogenesis, there are no precise and effective therapeutic targets for preeclampsia, and the only available treatment strategy is to terminate the pregnancy and eliminate the clinical symptoms. In recent years, non-coding RNAs have become a hotspot in preeclampsia research and have shown promise as effective biomarkers for the early diagnosis of preeclampsia over conventional biochemical markers. PIWI-interacting RNAs, novel small non-coding RNA that interact with PIWI proteins, are involved in the pathogenesis of various diseases at the transcriptional or post-transcriptional level. However, the mechanisms underlying the role of PIWI-interacting RNAs in the pathogenesis of preeclampsia remain unclear. In this review, we discuss the findings of existing studies on PIWI-interacting RNA biogenesis, functions, and their possible roles in preeclampsia, providing novel insights into the potential application of PIWI-interacting RNAs in the early diagnosis and clinical treatment of preeclampsia.

Exploring the impact of N4-acetylcytidine modification in RNA on non-neoplastic disease: unveiling its role in pathogenesis and therapeutic opportunities

RNA modifications include not only methylation modifications, such as m6A, but also acetylation modifications, which constitute a complex interaction involving "writers," "readers," and "erasers" that play crucial roles in growth, genetics, and disease. N4-acetylcytidine (ac4C) is an ancient and highly conserved RNA modification that plays a profound role in the pathogenesis of a wide range of diseases. This review provides insights into the functional impact of ac4C modifications in disease and introduces new perspectives for disease treatment. These studies provide important insights into the biological functions of post-transcriptional RNA modifications and their potential roles in disease mechanisms, offering new perspectives and strategies for disease treatment.

RNA-mediated epigenetic regulation in exercised heart: Mechanisms and opportunities for intervention

Physical exercise has been widely acknowledged as a beneficial lifestyle alteration and a potent non-pharmacological treatment for heart disease. Extensive investigations have revealed the beneficial effects of exercise on the heart and the underlying mechanisms involved. Exercise is considered one of the key factors that can lead to epigenetic alterations. The increasing number of identified molecules in the exercised heart has led to many studies in recent years that have explored the cellular function of ncRNAs and RNA modifications in the heart. Investigating the regulatory role of RNA-mediated epigenetic regulation in exercised hearts will contribute to the development of therapeutic strategies for the management of heart diseases. This review aims to summarize the positive impact of exercise on cardiac health. We will first provide an overview of the mechanisms through which exercise offers protection to the heart. Subsequently, we will delve into the current understanding of ncRNAs, specifically miRNAs, lncRNAs, and circRNAs, as well as RNA modification, focusing on RNA m6A and RNA A-to-I editing, and how they contribute to exercise-induced benefits for the heart. Lastly, we will explore the emerging therapeutic strategies that utilize exercise-mediated RNA epigenetic regulation in the treatment of heart diseases, while also addressing the challenges faced in this field.

NAT10-mediated ac4C modification promotes ectoderm differentiation of human embryonic stem cells via acetylating NR2F1 mRNA

Cell fate determination in mammalian development is complex and precisely controlled and accumulating evidence indicates that epigenetic mechanisms are crucially involved. N4-acetylcytidine (ac4C) is a recently identified modification of messenger RNA (mRNA); however, its functions are still elusive in mammalian. Here, we show that N-acetyltransferase 10 (NAT10)-mediated ac4C modification promotes ectoderm differentiation of human embryonic stem cells (hESCs) by acetylating nuclear receptor subfamily 2 group F member 1 (NR2F1) mRNA to enhance translation efficiency (TE). Acetylated RNA immunoprecipitation sequencing (acRIP-seq) revealed that levels of ac4C modification were higher in ectodermal neuroepithelial progenitor (NEP) cells than in hESCs or mesoendoderm cells. In addition, integrated analysis of acRIP-seq and ribosome profiling sequencing revealed that NAT10 catalysed ac4C modification to improve TE in NEP cells. RIP-qRT-PCR analysis identified an interaction between NAT10 and NR2F1 mRNA in NEP cells and NR2F1 accelerated the nucleus-to-cytoplasm translocation of yes-associated protein 1, which contributed to ectodermal differentiation of hESCs. Collectively, these findings point out the novel regulatory role of ac4C modification in the early ectodermal differentiation of hESCs and will provide a new strategy for the treatment of neuroectodermal defects diseases.

Nanopore Identification of N-Acetylation by Hydroxylamine Deacetylation (NINAHD)

N-Acetyl modification, a chemical modification commonly found on biomacromolecules, plays a crucial role in the regulation of cell activities and is related to a variety of diseases. However, due to the instability of N-acetyl modification, accurate and rapid identification of N-acetyl modification with a low measurement cost is still technically challenging. Here, based on hydroxylamine deacetylation and nanopore single molecule chemistry, a universal sensing strategy for N-acetyl modification has been developed. Acetohydroxamic acid (AHA), which is produced by the hydroxylamine deacetylation reaction and serves as a reporter for N-acetylation identification, is specifically sensed by a phenylboronic acid (PBA)-modified Mycobacterium smegmatis porin A (MspA). With this strategy, N-acetyl modifications on RNA, DNA, proteins, and glycans were identified, demonstrating its generality. Specifically, histones can be treated with hydroxylamine deacetylation, from which the generated AHA can represent the amount of N-acetyl modification detected by a nanopore sensor. The unique event features of AHA also demonstrate the robustness of sensing against other interfering analytes in the environment.

Polystyrene nanoplastics induce vascular stenosis via regulation of the PIWI-interacting RNA expression profile

Nanoplastics (NPs) have become common worldwide and attracted increasing attention due to their serious toxic effects. Owing to their higher surface area and volume ratios and ability to easily enter tissues, NPs impose more serious toxic effects than microplastics. However, the effect of NP exposure on vascular stenosis remains unclear. To measure the effects of polystyrene NP (PS-NP) exposure on vascular toxicity, we conducted analyses of blood biochemical parameters, pathological histology, high-throughput sequencing, and bioinformatics. Red fluorescent PS-NPs (100 nm) were effectively uptake by mouse vascular arterial tissue. The uptake of PS-NPs resulted in vascular toxicity, including alterations in lipid metabolism and thickening of the arterial wall. Based on PIWI-interacting RNA (piRNA) sequencing, 1547 and 132 differentially expressed piRNAs (DEpiRNAs) were detected in the PS-NP treatment group after 180 and 30 days, including 787 and 86 upregulated and 760 and 46 downregulated compared with the control group, respectively. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses indicated that the target genes of DEpiRNAs were mostly involved in cell growth and cell motility-related signaling, such as the MAPK signaling pathway. This is the first study to highlight the alteration in piRNA levels in mouse vascular arterial tissue after PS-NP exposure. This study adds to the knowledge regarding the regulatory mechanism of pathological changes induced by PS-NP exposure.

N-Acetyltransferase 10 represses Uqcr11 and Uqcrb independently of ac4C modification to promote heart regeneration

Translational control is crucial for protein production in various biological contexts. Here, we use Ribo-seq and RNA-seq to show that genes related to oxidative phosphorylation are translationally downregulated during heart regeneration. We find that Nat10 regulates the expression of Uqcr11 and Uqcrb mRNAs in mouse and human cardiomyocytes. In mice, overexpression of Nat10 in cardiomyocytes promotes cardiac regeneration and improves cardiac function after injury. Conversely, treating neonatal mice with Remodelin-a Nat10 pharmacological inhibitor-or genetically removing Nat10 from their cardiomyocytes both inhibit heart regeneration. Mechanistically, Nat10 suppresses the expression of Uqcr11 and Uqcrb independently of its ac4C enzyme activity. This suppression weakens mitochondrial respiration and enhances the glycolytic capacity of the cardiomyocytes, leading to metabolic reprogramming. We also observe that the expression of Nat10 is downregulated in the cardiomyocytes of P7 male pig hearts compared to P1 controls. The levels of Nat10 are also lower in female human failing hearts than non-failing hearts. We further identify the specific binding regions of Nat10, and validate the pro-proliferative effects of Nat10 in cardiomyocytes derived from human embryonic stem cells. Our findings indicate that Nat10 is an epigenetic regulator during heart regeneration and could potentially become a clinical target.

Unlocking the dark matter: noncoding RNAs and RNA modifications in cardiac aging

Cardiac aging is a multifaceted process that encompasses structural and functional alterations culminating in heart failure. As the elderly population continues to expand, there is a growing urgent need for interventions to combat age-related cardiac functional decline. Noncoding RNAs have emerged as critical regulators of cellular and biochemical processes underlying cardiac disease. This review summarizes our current understanding of how noncoding RNAs function in the heart during aging, with particular emphasis on mechanisms of RNA modification that control their activity. Targeting noncoding RNAs as potential novel therapeutics in cardiac aging is also discussed.

Revealing the pharmacological effects of Remodelin against osteosarcoma based on network pharmacology, acRIP-seq and experimental validation

Osteosarcoma (OS) is the most common primary malignant tumor of bone. Remodelin, an inhibitor of the N (4)-Acetylcytidine (ac4C) acetylation modifying enzyme N-acetyltransferase 10 (NAT10), has been shown to have therapeutic effects on cancer in several studies, and our previous studies have confirmed the inhibitory effect of Remodelin on OS cells, however, the mechanism of action has not yet been elucidated. We used network pharmacological analysis to quantify the therapeutic targets of Remodelin against OS. acRIP-seq and RNA-seq were performed to investigate the inhibitory activity of Remodelin on acetylation and its effect on the transcriptome after intervening in OS cells U2OS with Remodelin in vitro. Key target genes were deduced based on their pharmacological properties, combined with network pharmacology results and sequencing results. Finally, the deduced target genes were validated with vitro experiments. Network pharmacological analysis showed that 2291 OS-related target genes and 369 Remodelin-related target genes were obtained, and 116 overlapping genes were identified as Remodelin targets for OS treatment. Sequencing results showed that a total of 13,736 statistically significant ac4C modification peaks were detected by acRIP-seq, including 6938 hypoacetylation modifications and 6798 hyperacetylation modifications. A total of 2350 statistically significant mRNAs were detected by RNA-seq, of which 830 were up-regulated and 1520 were down-regulated. Association analyses identified a total of 382 genes that were Hypoacetylated-down, consistent with inhibition of mRNA acetylation and expression by Remodelin. Five genes, CASP3, ESR2, FGFR2, IGF1 and MAPK1, were identified as key therapeutic targets of Remodelin against OS. Finally, in vitro experiments, CCK-8 and qRT-PCR demonstrated that Remodelin indeed inhibited the proliferation of OS cells and reduced the expression of three genes: ESR2, IGF1, and MAPK1. In conclusion, ESR2, IGF1 and MAPK1 were identified as key therapeutic targets of Remodelin against OS. This reveals the target of Remodelin's pharmacological action on OS and provides new ideas for the treatment of OS.

N4-acetylcytidine modifies primary microRNAs for processing in cancer cells

N4 acetylcytidine (ac4C) modification mainly occurs on tRNA, rRNA, and mRNA, playing an important role in the expression of genetic information. However, it is still unclear whether microRNAs have undergone ac4C modification and their potential physiological and pathological functions. In this study, we identified that NAT10/THUMPD1 acetylates primary microRNAs (pri-miRNAs) with ac4C modification. Knockdown of NAT10 suppresses and augments the expression levels of mature miRNAs and pri-miRNAs, respectively. Molecular mechanism studies found that pri-miRNA ac4C promotes the processing of pri-miRNA into precursor miRNA (pre-miRNA) by enhancing the interaction of pri-miRNA and DGCR8, thereby increasing the biogenesis of mature miRNA. Knockdown of NAT10 attenuates the oncogenic characters of lung cancer cells by regulating miRNA production in cancers. Moreover, NAT10 is highly expressed in various clinical cancers and negatively correlated with poor prognosis. Thus, our results reveal that NAT10 plays a crucial role in cancer initiation and progression by modulating pri-miRNA ac4C to affect miRNA production, which would provide an attractive therapeutic strategy for cancers.

Emerging roles of RNA ac4C modification and NAT10 in mammalian development and human diseases

RNA ac4C modification is a novel and rare chemical modification observed in mRNA. Traditional biochemical studies had primarily associated ac4C modification with tRNA and rRNA until in 2018, Arango D et al. first reported the presence of ac4C modification on mRNA and demonstrated its critical role in mRNA stability and translation regulation. Furthermore, they established that the ac4C modification on mRNA is mediated by the classical N-acetyltransferase NAT10. Subsequent studies have underscored the essential implications of NAT10 and mRNA ac4C modification across both physiological and pathological regulatory processes. In this review, we aimed to explore the discovery history of RNA ac4C modification, its detection methods, and its regulatory mechanisms in disease and physiological development. We offer a forward-looking examination and discourse concerning the employment of RNA ac4C modification as a prospective therapeutic strategy across diverse diseases. Furthermore, we comprehensively summarize the functions and mechanisms of NAT10 in gene expression regulation and pathogenesis independent of RNA ac4C modification.

NAT10 Is Involved in Cardiac Remodeling Through ac4C-Mediated Transcriptomic Regulation

BACKGROUND

Heart failure, characterized by cardiac remodeling, is associated with abnormal epigenetic processes and aberrant gene expression. Here, we aimed to elucidate the effects and mechanisms of NAT10 (N-acetyltransferase 10)-mediated N4-acetylcytidine (ac4C) acetylation during cardiac remodeling.

METHODS

NAT10 and ac4C expression were detected in both human and mouse subjects with cardiac remodeling through multiple assays. Subsequently, acetylated RNA immunoprecipitation and sequencing, thiol-linked alkylation for the metabolic sequencing of RNA (SLAM-seq), and ribosome sequencing (Ribo-seq) were employed to elucidate the role of ac4C-modified posttranscriptional regulation in cardiac remodeling. Additionally, functional experiments involving the overexpression or knockdown of NAT10 were conducted in mice models challenged with Ang II (angiotensin II) and transverse aortic constriction.

RESULTS

NAT10 expression and RNA ac4C levels were increased in in vitro and in vivo cardiac remodeling models, as well as in patients with cardiac hypertrophy. Silencing and inhibiting NAT10 attenuated Ang II-induced cardiomyocyte hypertrophy and cardiofibroblast activation. Next-generation sequencing revealed ac4C changes in both mice and humans with cardiac hypertrophy were associated with changes in global mRNA abundance, stability, and translation efficiency. Mechanistically, NAT10 could enhance the stability and translation efficiency of CD47 and ROCK2 transcripts by upregulating their mRNA ac4C modification, thereby resulting in an increase in their protein expression during cardiac remodeling. Furthermore, the administration of Remodelin, a NAT10 inhibitor, has been shown to prevent cardiac functional impairments in mice subjected to transverse aortic constriction by suppressing cardiac fibrosis, hypertrophy, and inflammatory responses, while also regulating the expression levels of CD47 and ROCK2 (Rho associated coiled-coil containing protein kinase 2).

CONCLUSIONS

Therefore, our data suggest that modulating epitranscriptomic processes, such as ac4C acetylation through NAT10, may be a promising therapeutic target against cardiac remodeling.

HNEAP Regulates Necroptosis of Cardiomyocytes by Suppressing the m5 C Methylation of Atf7 mRNA

PIWI-interacting RNAs (piRNAs) are highly expressed in various cardiovascular diseases. However, their role in cardiomyocyte death caused by ischemia/reperfusion (I/R) injury, especially necroptosis, remains elusive. In this study, a heart necroptosis-associated piRNA (HNEAP) is found that regulates cardiomyocyte necroptosis by targeting DNA methyltransferase 1 (DNMT1)-mediated 5-methylcytosine (m5 C) methylation of the activating transcription factor 7 (Atf7) mRNA transcript. HNEAP expression level is significantly elevated in hypoxia/reoxygenation (H/R)-exposed cardiomyocytes and I/R-injured mouse hearts. Loss of HNEAP inhibited cardiomyocyte necroptosis and ameliorated cardiac function in mice. Mechanistically, HNEAP directly interacts with DNMT1 and attenuates m5 C methylation of the Atf7 mRNA transcript, which increases Atf7 expression level. ATF7 can further downregulate the transcription of Chmp2a, an inhibitor of necroptosis, resulting in the reduction of Chmp2a level and the progression of cardiomyocyte necroptosis. The findings reveal that piRNA-mediated m5 C methylation is involved in the regulation of cardiomyocyte necroptosis. Thus, the HNEAP-DNMT1-ATF7-CHMP2A axis may be a potential target for attenuating cardiac injury caused by necroptosis in ischemic heart disease.

Expression and diagnostic value of PIWI-interacting RNA by serum in acute myocardial infarction

OBJECTIVE

To detect the expression level of PIWI-interacting RNA in the serum of patients with acute myocardial infarction, and to explore the role of PIWI-interacting RNA in acute myocardial infarction.

METHODS

RNA was extracted from the serum of acute myocardial infarction patients and healthy subjects, and high-throughput sequencing of PIWI-interacting RNAs was performed to screen differentially expressed PIWI-interacting RNAs. Quantitative polymerase chain reaction was used to detect the expression of four differentially expressed PIWI-interacting RNAs in 52 patients with acute myocardial infarction and 30 healthy people. Receiver operating characteristic (ROC) curve was further used to analyze the correlation between differentially expressed PIWI-interacting RNAs and the occurrence of acute myocardial infarction. Kyoto Encyclopedia of Genes and Genomes analysis was used to analyze the role of PIWI-interacting RNA in the occurrence of acute myocardial infarction.

RESULTS

RNA sequencing and bioinformatics analysis revealed that most piRNAs were upregulated in AMI patients, with 195 upregulated and 13 downregulated. Among them, piR-hsa-9010, piR-hsa-28646, and piR-hsa-23619 were significantly up-regulated in the serum of patients with acute myocardial infarction, but their expression in the acute heart failure group and coronary heart disease group was not significantly different from that in the healthy group. ROC curve analysis showed that piR-hsa-9010, piR-hsa-28646, and piR-hsa-23619 had high diagnostic values in acute myocardial infarction. In vitro, there was no significant difference in the expression of piR-hsa-9010 among THP-1, HUVEC, and AC16, while the expression of piR-hsa-28646 and piR-hsa-23619 in HUVEC was significantly higher than that in THP-1 and AC16. Pathway analysis showed that piR-hsa-23619 was mainly involved in TNF signaling pathway, and piR-hsa-28646 was mainly involved in Wnt signaling pathway.

CONCLUSION

piR-hsa-9010, piR-hsa-28646, and piR-hsa-23619 were significantly up-regulated in the serum of patients with acute myocardial infarction. It can be used as a new biomarker for the diagnosis of acute myocardial infarction, which may be a therapeutic target for acute myocardial infarction.

Novel roles of PIWI proteins and PIWI-interacting RNAs in human health and diseases

Non-coding RNA has aroused great research interest recently, they play a wide range of biological functions, such as regulating cell cycle, cell proliferation, and intracellular substance metabolism. Piwi-interacting RNAs (piRNAs) are emerging small non-coding RNAs that are 24-31 nucleotides in length. Previous studies on piRNAs were mainly limited to evaluating the binding to the PIWI protein family to play the biological role. However, recent studies have shed more lights on piRNA functions; aberrant piRNAs play unique roles in many human diseases, including diverse lethal cancers. Therefore, understanding the mechanism of piRNAs expression and the specific functional roles of piRNAs in human diseases is crucial for developing its clinical applications. Presently, research on piRNAs mainly focuses on their cancer-specific functions but lacks investigation of their expressions and epigenetic modifications. This review discusses piRNA's biogenesis and functional roles and the recent progress of functions of piRNA/PIWI protein complexes in human diseases. Video Abstract.

RNA modification in cardiovascular disease: implications for therapeutic interventions

Cardiovascular disease (CVD) is the leading cause of death in the world, with a high incidence and a youth-oriented tendency. RNA modification is ubiquitous and indispensable in cell, maintaining cell homeostasis and function by dynamically regulating gene expression. Accumulating evidence has revealed the role of aberrant gene expression in CVD caused by dysregulated RNA modification. In this review, we focus on nine common RNA modifications: N6-methyladenosine (m6A), N1-methyladenosine (m1A), 5-methylcytosine (m5C), N7-methylguanosine (m7G), N4-acetylcytosine (ac4C), pseudouridine (Ψ), uridylation, adenosine-to-inosine (A-to-I) RNA editing, and modifications of U34 on tRNA wobble. We summarize the key regulators of RNA modification and their effects on gene expression, such as RNA splicing, maturation, transport, stability, and translation. Then, based on the classification of CVD, the mechanisms by which the disease occurs and progresses through RNA modifications are discussed. Potential therapeutic strategies, such as gene therapy, are reviewed based on these mechanisms. Herein, some of the CVD (such as stroke and peripheral vascular disease) are not included due to the limited availability of literature. Finally, the prospective applications and challenges of RNA modification in CVD are discussed for the purpose of facilitating clinical translation. Moreover, we look forward to more studies exploring the mechanisms and roles of RNA modification in CVD in the future, as there are substantial uncultivated areas to be explored.

Antibody-Free Fluorine-Assisted Metabolic Sequencing of RNA N4-Acetylcytidine

N4-Acetylcytidine (ac4C) has been found to affect a variety of cellular and biological processes. For a mechanistic understanding of the roles of ac4C in biology and disease, we present an antibody-free, fluorine-assisted metabolic sequencing method to detect RNA ac4C, called "FAM-seq". We successfully applied FAM-seq to profile ac4C landscapes in human 293T, HeLa, and MDA cell lines in parallel with the reported acRIP-seq method. By comparison with the classic ac4C antibody sequencing method, we found that FAM-seq is a convenient and reliable method for transcriptome-wide mapping of ac4C. Because this method holds promise for detecting nascent RNA ac4C modifications, we further investigated the role of ac4C in regulating chemotherapy drug resistance in chronic myeloid leukemia. The results indicated that drug development or combination therapy could be enhanced by appreciating the key role of ac4C modification in cancer therapy.

Activated SIRT1 contributes to DPT-induced glioma cell parthanatos by upregulation of NOX2 and NAT10

Parthanatos is a type of programmed cell death dependent on hyper-activation of poly (ADP-ribose) polymerase 1 (PARP-1). SIRT1 is a highly conserved nuclear deacetylase and often acts as an inhibitor of parthanatos by deacetylation of PARP1. Our previous study showed that deoxypodophyllotoxin (DPT), a natural compound isolated from the traditional herb Anthriscus sylvestris, triggered glioma cell death via parthanatos. In this study, we investigated the role of SIRT1 in DPT-induced human glioma cell parthanatos. We showed that DPT (450 nmol/L) activated both PARP1 and SIRT1, and induced parthanatos in U87 and U251 glioma cells. Activation of SIRT1 with SRT2183 (10 μmol/L) enhanced, while inhibition of SIRT1 with EX527 (200 μmol/L) or knockdown of SIRT1 attenuated DPT-induced PARP1 activation and glioma cell death. We demonstrated that DPT (450 nmol/L) significantly decreased intracellular NAD+ levels in U87 and U251 cells. Further decrease of NAD+ levels with FK866 (100 μmol/L) aggravated, but supplement of NAD+ (0.5, 2 mmol/L) attenuated DPT-induced PARP1 activation. We found that NAD+ depletion enhanced PARP1 activation via two ways: one was aggravating ROS-dependent DNA DSBs by upregulation of NADPH oxidase 2 (NOX2); the other was reinforcing PARP1 acetylation via increase of N-acetyltransferase 10 (NAT10) expression. We found that SIRT1 activity was improved when being phosphorylated by JNK at Ser27, the activated SIRT1 in reverse aggravated JNK activation via upregulating ROS-related ASK1 signaling, thus forming a positive feedback between JNK and SIRT1. Taken together, SIRT1 activated by JNK contributed to DPT-induced human glioma cell parthanatos via initiation of NAD+ depletion-dependent upregulation of NOX2 and NAT10.

N4-acetylcytidine of Nop2 mRNA is required for the transition of morula-to-blastocyst

N-acetyltransferase 10 (NAT10)-mediated N4-acetylcytidine (ac4C) modification is crucial for mRNA stability and translation efficiency, yet the underlying function in mammalian preimplantation embryos remains unclear. Here, we characterized the ac4C modification landscape in mouse early embryos and found that the majority of embryos deficient in ac4C writer-NAT10 failed to develop into normal blastocysts. Through single-cell sequencing, RNA-seq, acetylated RNA immunoprecipitation combined with PCR (acRIP-PCR), and embryonic phenotype monitoring, Nop2 was screened as a target gene of Nat10. Mechanistically, Nat10 knockdown decreases the ac4C modification on Nop2 mRNA and reduces RNA and protein abundance by affecting the mRNA stability of Nop2. Then, depletion of NOP2 may inhibit the translation of transcription factor TEAD4, resulting in defective expression of the downstream lineage-specific gene Cdx2, and ultimately preventing blastomeres from undergoing the trophectoderm (TE) fate. However, exogenous Nop2 mRNA partially reverses this abnormal development. In conclusion, our findings demonstrate that defective ac4C modification of Nop2 mRNA hinders the morula-to-blastocyst transition by influencing the first cell fate decision in mice.

RNA modification: mechanisms and therapeutic targets

RNA modifications are dynamic and reversible chemical modifications on substrate RNA that are regulated by specific modifying enzymes. They play important roles in the regulation of many biological processes in various diseases, such as the development of cancer and other diseases. With the help of advanced sequencing technologies, the role of RNA modifications has caught increasing attention in human diseases in scientific research. In this review, we briefly summarized the basic mechanisms of several common RNA modifications, including m6A, m5C, m1A, m7G, Ψ, A-to-I editing and ac4C. Importantly, we discussed their potential functions in human diseases, including cancer, neurological disorders, cardiovascular diseases, metabolic diseases, genetic and developmental diseases, as well as immune disorders. Through the "writing-erasing-reading" mechanisms, RNA modifications regulate the stability, translation, and localization of pivotal disease-related mRNAs to manipulate disease development. Moreover, we also highlighted in this review all currently available RNA-modifier-targeting small molecular inhibitors or activators, most of which are designed against m6A-related enzymes, such as METTL3, FTO and ALKBH5. This review provides clues for potential clinical therapy as well as future study directions in the RNA modification field. More in-depth studies on RNA modifications, their roles in human diseases and further development of their inhibitors or activators are needed for a thorough understanding of epitranscriptomics as well as diagnosis, treatment, and prognosis of human diseases.

N4-Acetylcytidine Drives Glycolysis Addiction in Gastric Cancer via NAT10/SEPT9/HIF-1α Positive Feedback Loop

Anti-angiogenic therapy has long been considered a promising strategy for solid cancers. Intrinsic resistance to hypoxia is a major cause for the failure of anti-angiogenic therapy, but the underlying mechanism remains unclear. Here, it is revealed that N4-acetylcytidine (ac4C), a newly identified mRNA modification, enhances hypoxia tolerance in gastric cancer (GC) cells by promoting glycolysis addiction. Specifically, acetyltransferase NAT10 transcription is regulated by HIF-1α, a key transcription factor of the cellular response to hypoxia. Further, acRIP-sequencing, Ribosome profiling sequencing, RNA-sequencing, and functional studies confirm that NAT10 in turn activates the HIF-1 pathway and subsequent glucose metabolism reprogramming by mediating SEPT9 mRNA ac4C modification. The formation of the NAT10/SEPT9/HIF-1α positive feedback loop leads to excessive activation of the HIF-1 pathway and induces glycolysis addiction. Combined anti-angiogenesis and ac4C inhibition attenuate hypoxia tolerance and inhibit tumor progression in vivo. This study highlights the critical roles of ac4C in the regulation of glycolysis addiction and proposes a promising strategy to overcome resistance to anti-angiogenic therapy by combining apatinib with ac4C inhibition.

PiRNA in Cardiovascular Disease: Focus on Cardiac Remodeling and Cardiac Protection

Cardiovascular diseases (CVDs) are common causes of death, which take about 18.6 million lives worldwide every year. Currently, exploring strategies that delay ventricular remodeling, reduce cardiomyocyte death, and promote cardiomyocyte regeneration has been the hotspot and difficulty of the ischemic heart disease (IHD) research field. Previous studies indicate that piwi-interacting RNA (piRNA) plays a vital role in the occurrence and development of cardiac remodeling and may offer novel therapeutic strategies for cardiac repair. The best-known biological function of piRNA is to silence transposons in cells. In the cardiovascular system, piRNA is known to participate in cardiac progenitor cell proliferation, AKT pathway regulation, and cardiac remodeling and decompensation. In this review, we systematically discuss the research progress on piRNA in CVDs, especially the mechanism of cardiac remodeling and the potential functions in cardiac protection, which provides new insights for the progress and treatment of cardiovascular diseases. Piwi-interacting RNA (piRNA) is one of the noncoding RNAs, with the best -known biological function to silence transposons in cells. Now piRNA is found to participate in cardiac progenitor cell proliferation, AKT pathway regulation, cardiac remodeling and decompensation, which implies the potential of piRNA in the diagnosis and treatment of cardiovascular diseases. Over expression of piRNA could promote cardiac apoptosis and cardiac hypertrophy, thus targeted therapy which inhibits expression of associated piRNA may reduce cardiac remodeling and reduce inflammation caused by necrotic cardiomyocytes. PiRNA is also speculated to participate in the proliferation of cardiac progenitor cells, implying the potential to induce cardiac regeneration th erapy, which provides new insights for treatment of cardiovascular diseases. At present, the treatment strategy of cardiac remodeling emphasizes the control of risk factors, prevention of disease progression and individualized treatment. With further studies in mechanism of piRNA, potential therapies above may come true and more therapies in cardiovascular diseases may be found.

The Cytidine N-Acetyltransferase NAT10 Participates in Peripheral Nerve Injury-Induced Neuropathic Pain by Stabilizing SYT9 Expression in Primary Sensory Neurons

RNA N4-acetylcytidine (ac4C) modification is increasingly recognized as an important layer of gene regulation; however, the involvement of ac4C in pain regulation has not been studied. Here, we report that N-acetyltransferase 10 protein (NAT10; the only known ac4C "writer") contributes to the induction and development of neuropathic pain in an ac4C-dependent manner. Peripheral nerve injury increases the levels of NAT10 expression and overall ac4C in injured dorsal root ganglia (DRGs). This upregulation is triggered by the activation of upstream transcription factor 1 (USF1), a transcription factor that binds to the Nat10 promoter. Knock-down or genetic deletion of NAT10 in the DRG abolishes the gain of ac4C sites in Syt9 mRNA and the augmentation of SYT9 protein, resulting in a marked antinociceptive effect in nerve-injured male mice. Conversely, mimicking NAT10 upregulation in the absence of injury evokes the elevation of Syt9 ac4C and SYT9 protein and induces the genesis of neuropathic-pain-like behaviors. These findings demonstrate that USF1-governed NAT10 regulates neuropathic pain by targeting Syt9 ac4C in peripheral nociceptive sensory neurons. Our findings establish NAT10 as a critical endogenous initiator of nociceptive behavior and a promising new target for treating neuropathic pain.SIGNIFICANCE STATEMENT The cytidine N4-acetylcytidine (ac4C), a new epigenetic RNA modification, is crucial for the translation and stability of mRNA, but its role for chronic pain remains unclear. Here, we demonstrate that N-acetyltransferase 10 (NAT10) acts as ac4C N-acetyltransferase and plays an important role in the development and maintenance of neuropathic pain. NAT10 was upregulated via the activation of the transcription factor upstream transcription factor 1 (USF1) in the injured dorsal root ganglion (DRG) after peripheral nerve injury. Since pharmacological or genetic deleting NAT10 in the DRG attenuated the nerve injury-induced nociceptive hypersensitivities partially through suppressing Syt9 mRNA ac4C and stabilizing SYT9 protein level, NAT10 may serve as an effective and novel therapeutic target for neuropathic pain.

Koumine induces apoptosis in Cyprinus carpio liver cells by regulating JAK-STAT and p53 signaling pathways

Koumine is an alkaloid with significant anti-anxiety, anticancer cell proliferation, and analgesic activities, and our previous studies have shown that koumine can be used as an immunostimulant in aquaculture, but the molecular mechanism of its effect remains unclear. We fed a basal diet with 0, 0.2, 2, and 20 mg/kg koumine to C. carpio for 10 weeks, and comprehensive studies of the histological and biochemical parameters and transcriptomes of the four groups were performed. Histological results indicated that the number of apoptotic cells in the liver increased with increasing koumine concentration. Compared with those of the control group, the malondialdehyde, superoxide dismutase, catalase, acid phosphatase, alkaline phosphatase, and lactate dehydrogenase levels of the treatment group increased to varying degrees. In total, 100.11 GB of clean data, 4774 DEGs, and 138 differentially expressed genes were obtained from the transcriptome data. Differentially expressed genes were classified into 187 signalling pathways, and the circadian rhythm signalling pathway, the JAK-STAT signalling pathway, the p53 signalling pathway and the PPAR signalling pathway were the top enriched pathways. The qRT-PCR results confirmed that the key genes ifnar1, socs3l, epoa, ghra, cMyc, mcl-1, shisa4, and gtse1 involved in balancing cell proliferation and apoptosis were enriched in these pathways. We discovered that the JAK-STAT and p53 pathways are important targets of koumine. Such information contributes to a better understanding of the potential mechanism by which koumine regulates hepatic immunity as well as to lays the theoretical foundation for its application.

Acetyltransferase NAT10 regulates the Wnt/β-catenin signaling pathway to promote colorectal cancer progression via ac4C acetylation of KIF23 mRNA

BACKGROUND

N4-acetylcytidine (ac4C) as a significant RNA modification has been reported to maintain the stability of mRNA and to regulate the translation process. However, the roles of both ac4C and its 'writer' protein N-acetyltransferase 10 (NAT10) played in the disease especially colorectal cancer (CRC) are unclear. At this point, we discover the underlying mechanism of NAT10 modulating the progression of CRC via mRNA ac4C modification.

METHODS

The clinical significance of NAT10 was explored based on the TCGA and GEO data sets and the 80 CRC patients cohort of our hospital. qRT-PCR, dot blot, WB, and IHC were performed to detect the level of NAT10 and ac4C modification in CRC tissues and matched adjacent tissues. CCK-8, colony formation, transwell assay, mouse xenograft, and other in vivo and in vitro experiments were conducted to probe the biological functions of NAT10. The potential mechanisms of NAT10 in CRC were clarified by RNA-seq, RIP-seq, acRIP-seq, luciferase reporter assays, etc. RESULTS: The levels of NAT10 and ac4C modification were significantly upregulated. Also, the high expression of NAT10 had important clinical values like poor prognosis, lymph node metastasis, distant metastasis, etc. Furthermore, the in vitro experiments showed that NAT10 could inhibit apoptosis and enhance the proliferation, migration, and invasion of CRC cells and also arrest them in the G2/M phase. The in vivo experiments discovered that NAT10 could promote tumor growth and liver/lung metastasis. In terms of mechanism, NAT10 could mediate the stability of KIF23 mRNA by binding to its mRNA 3'UTR region and up-regulating its mRNA ac4c modification. And then the protein level of KIF23 was elevated to activate the Wnt/β-catenin pathway and more β-catenin was transported into the nucleus which led to the CRC progression. Besides, the inhibitor of NAT10, remodelin, was applied in vitro and vivo which showed an inhibitory effect on the CRC cells.

CONCLUSIONS

NAT10 promotes the CRC progression through the NAT10/KIF23/GSK-3β/β-catenin axis and its expression is mediated by GSK-3β which forms a feedback loop. Our findings provide a potential prognosis or therapeutic target for CRC and remodelin deserves more attention.

Emerging roles of ferroptosis in cardiovascular diseases

The mechanism of cardiovascular diseases (CVDs) is complex and threatens human health. Cardiomyocyte death is an important participant in the pathophysiological basis of CVDs. Ferroptosis is a new type of iron-dependent programmed cell death caused by excessive accumulation of iron-dependent lipid peroxides and reactive oxygen species (ROS) and abnormal iron metabolism. Ferroptosis differs from other known cell death pathways, such as apoptosis, necrosis, necroptosis, autophagy and pyroptosis. Several compounds have been shown to induce or inhibit ferroptosis by regulating related key factors or signalling pathways. Recent studies have confirmed that ferroptosis is associated with the development of diverse CVDs and may be a potential therapeutic drug target for CVDs. In this review, we summarize the characteristics and related mechanisms of ferroptosis and focus on its role in CVDs, with the goal of inspiring novel treatment strategies.