Ropinirole suppresses LPS-induced periodontal inflammation by inhibiting the NAT10 in an ac4C-dependent manner.

BACKGROUND: Periodontitis is a chronic osteolytic inflammatory disease, where anti-inflammatory intervention is critical for restricting periodontal damage and regenerating alveolar bone. Ropinirole, a dopamine D2 receptor agonist, has previously shown therapeutic potential for periodontitis but the underlying mechanism is still unclear. METHODS: Human gingival fibroblasts (HGFs) treated with LPS were considered to mimic periodontitis in vitro. The dosage of Ropinirole was selected through the cell viability of HGFs evaluation. The protective effects of Ropinirole on HGFs were evaluated by detecting cell viability, cell apoptosis, and pro-inflammatory factor levels. The molecular docking between NAT10 and Ropinirole was performed. The interaction relationship between NAT10 and KLF6 was verified by ac4C Acetylated RNA Immunoprecipitation followed by qPCR (acRIP-qPCR) and dual-luciferase reporter assay. RESULTS: Ropinirole alleviates LPS-induced damage of HGFs by promoting cell viability, inhibiting cell apoptosis and the levels of IL-1ß, IL-18, and TNF-α. Overexpression of NAT10 weakens the effects of Ropinirole on protecting HGFs. Meanwhile, NAT10-mediated ac4C RNA acetylation promotes KLF6 mRNA stability. Upregulation of KLF6 reversed the effects of NAT10 inhibition on HGFs. CONCLUSIONS: Taken together, Ropinirole protected HGFs through inhibiting the NAT10 ac4C RNA acetylation to decrease the KLF6 mRNA stability from LPS injury. The discovery of this pharmacological and molecular mechanism of Ropinirole further strengthens its therapeutic potential for periodontitis.

Remodelin, a N-acetyltransferase 10 (NAT10) inhibitor, alters mitochondrial lipid metabolism in cancer cells.

Remodelin is a small molecule inhibitor of N-acetyltransferase 10 (NAT10), reported to reverse the effect of cancer conditions such as epithelial to mesenchymal transition, hypoxia, and drug resistance. We analysed RNA seq data of siNAT10 and found many metabolic pathways were altered, this made us perform unbiased metabolic analysis. Here we performed untargeted metabolomics in Remodelin treated cancer cells using high-performance liquid chromatography-tandem mass spectrometry. Statistical analysis revealed a total number of 138 of which 52 metabolites were significantly modified in Remodelin treated cells. Among the most significantly altered metabolites, we identified metabolites related with mitochondrial fatty acid elongation (MFAE) and mitochondrial beta-oxidation such as lauroyl-CoA, cholesterol, triglycerides, (S)-3-hydroxyhexadecanoyl-CoA, and NAD+ . Furthermore, assessment showed alteration in expression of Enoyl-CoA hydratase, short chain 1, mitochondrial (ECHS1), and Mitochondrial trans-2-enoyl-CoA reductase (MECR) genes, associated with MFAE pathway. We also found statistically significant decrease in total cholesterol and triglycerides in Remodelin treated cancer cells. Overall, our results showed that Remodelin alters mitochondrial fatty acid metabolism and lipid accumulation in cancer cells. Finally, we validated these results in NAT10 knockdown cancer cells and found that NAT10 reduction results in alteration in gene expression associated with mitochondrial fatty acid metabolism, clearly suggesting the possible role of NAT10 in maintaining mitochondrial fatty acid metabolism.

Down-regulation of NAA10 mediates the neuroprotection induced by sevoflurane preconditioning via regulating ERK1/2 phosphorylation.

OBJECTIVE: In the present study, the regulation mechanism of NAA10 (N-Alpha-Acetyltransferase 10) in sevoflurane preconditioning induced neuroprotective effect was explored. METHODS: Firstly, si-NAA10 or negative control (NC) were constructed for cell transfection and injected into intracerebroventricular of rats. Oxygen-glucose deprivation/reperfusion (OGD/R) model in vitro and middle cerebral artery occlusion (MCAO) model in vivo were established to simulate cerebral I/R injury. QRT-PCR analysis and western blotting assay were performed to assess the expression of NAA10. TTC staining, neurological evaluation and cell counting kit-8 (CCK-8) were performed to evaluate the effect of NAA10 on sevoflurane induced neuroprotection. TUNEL assay and flow cytometry were used to detect the apoptosis in vivo and in vitro. RESULTS: It showed that sevoflurane preconditioning increased the expression of NAA10 in MCAO rats. TTC staining, TUNEL assay and neurological evaluation results suggested that si-NAA10 attenuated the neuroprotective effect of sevoflurane preconditioning against MCAO. CCK-8 assay, flow cytometry, qRT-PCR and western blot results showed that NAA10 mediated sevoflurane preconditioning-induced neuroprotection in vitro. Furthermore, western blot results showed that down-regulation of NAA10 could reverse the attenuation of ERK1/2 phosphorylation induced by sevoflurane preconditioning in vivo or in vitro. CONCLUSION: Down-regulation of NAA10 regulated ERK1/2 phosphorylation mediating sevoflurane preconditioning induced neuroprotective effects. The results revealed the regulatory mechanism of NAA10 in the neuroprotective effect of sevoflurane preconditioning.

Structural insights of human N-acetyltransferase 10 and identification of its potential novel inhibitors.

N-acetyltransferase 10 (NAT10), is an acetyltransferase that regulates RNA stability and translation processes. Association of NAT10 with several diseases including cancer, makes it a promising therapeutic target. Remodelin is the only known NAT10 inhibitor, but the structural information related to its binding with NAT10 is still obscure. Here, we predicted the human NAT10 structure using homology modeling that was not available previously and used human NAT10 to identify the novel binding site(s) of Remodelin. The alignment of the modeled human NAT10 showed 24% identity and 37% positivity with crystal structure of tRNA (Met) cytidine acetyltransferase. Molecular docking showed binding of Remodelin with NAT10 in acetyl-CoA binding pocket. Additionally, we screened a library of FDA-approved drugs for the identification of novel inhibitors of NAT10 activity. Binding score showed that four drugs namely, Fosaprepitant (- 11.709), Leucal (- 10.46), Fludarabine (- 10.347) and Dantrolene (- 9.875) bind to NAT10 and have better binding capability when compared with Acetyl-CoA (- 5.691) and Remodelin (- 5.3). Acetyl-CoA, Remodelin, and others exhibit hits for hydrophobic, hydrophilic and hydrogen interactions. Interestingly, Remodelin and others interact with the amino acid residues ILE629, GLY639, GLY641, LEU719, and PHE722 in the Acetyl-CoA binding pocket of NAT10 similar to Acetyl-CoA. Our findings revealed that Fosaprepitant, Leucal, Fludarabine, and Dantrolene are promising molecules that can be tested and developed as potential inhibitors of NAT10 acetyltransferase activity.

Remodelin, an inhibitor of NAT10, could suppress hypoxia-induced or constitutional expression of HIFs in cells.

Hypoxia-inducible factors (HIFs) are key mediators expressed under hypoxic condition and involved in many kinds of disease such as cancer and abnormal angiogenesis. Thus, development of their inhibitor has been extensively explored. Here, we describe a finding that Remodelin, a specific inhibitor of NAT10, could also inhibit the expression of HIFs. The presence of Remodelin could suppress the elevated level of HIF-1α protein and its nuclear translocation induced by either treatment of cobalt chloride (CoCl2) or hypoxia in dose or time-dependent way. More importantly, Remodelin could also inhibit the constitutional expression of HIF-1α and HIF-2α in VHL mutant 786-0 cells. With using of cells with depletion of NAT10 by shRNA or Crispr-Cas9 edited, we further demonstrated that inhibition of HIFs by Remodelin should need NAT10 activity. In biological analysis, the treatment of cultured HUVECs with Remodelin could inhibit in vitro cell migration and invasion and tube-formation. Our investigation implied that Remodelin could be a new potential inhibitor of HIFs for using in angiogenesis targeting therapy in either cancers or inflammatory diseases.