Acetyl-CoA-dependent ac4C acetylation promotes the osteogenic differentiation of LPS-stimulated BMSCs.

The impaired osteogenic capability of bone marrow mesenchymal stem cells (BMSCs) caused by persistent inflammation is the main pathogenesis of inflammatory bone diseases. Recent studies show that metabolism is disturbed in osteogenically differentiated BMSCs in response to Lipopolysaccharide (LPS) treatment, while the mechanism involved remains incompletely revealed. Herein, we demonstrated that BMSCs adapted their metabolism to regulate acetyl-coenzyme A (acetyl-CoA) availability and RNA acetylation level, ultimately affecting osteogenic differentiation. The mitochondrial dysfunction and impaired osteogenic potential upon inflammatory conditions accompanied by the reduced acetyl-CoA content, which in turn suppressed N4-acetylation (ac4C) level. Supplying acetyl-CoA by sodium citrate (SC) addition rescued ac4C level and promoted the osteogenic capacity of LPS-treated cells through the ATP citrate lyase (ACLY) pathway. N-acetyltransferase 10 (NAT10) inhibitor remodelin reduced ac4C level and consequently impeded osteogenic capacity. Meanwhile, the osteo-promotive effect of acetyl-CoA-dependent ac4C might be attributed to fatty acid oxidation (FAO), as evidenced by activating FAO by L-carnitine supplementation counteracted remodelin-induced inhibition of osteogenesis. Further in vivo experiments confirmed the promotive role of acetyl-CoA in the endogenous bone regeneration in rat inflammatory mandibular defects. Our study uncovered a metabolic-epigenetic axis comprising acetyl-CoA and ac4C modification in the process of inflammatory osteogenesis of BMSCs and suggested a new target for bone tissue repair in the context of inflammatory bone diseases.

The positive feedback loop of the NAT10/Mybbp1a/p53 axis promotes cardiomyocyte ferroptosis to exacerbate cardiac I/R injury.

Ferroptosis is a nonapoptotic form of regulated cell death that has been reported to play a central role in cardiac ischemia‒reperfusion (I/R) injury. N-acetyltransferase 10 (NAT10) contributes to cardiomyocyte apoptosis by functioning as an RNA ac4c acetyltransferase, but its role in cardiomyocyte ferroptosis during I/R injury has not been determined. This study aimed to elucidate the role of NAT10 in cardiac ferroptosis as well as the underlying mechanism. The mRNA and protein levels of NAT10 were increased in mouse hearts after I/R and in cardiomyocytes that were exposed to hypoxia/reoxygenation. P53 acted as an endogenous activator of NAT10 during I/R in a transcription-dependent manner. Cardiac overexpression of NAT10 caused cardiomyocyte ferroptosis to exacerbate I/R injury, while cardiomyocyte-specific knockout of NAT10 or pharmacological inhibition of NAT10 with Remodelin had the opposite effects. The inhibition of cardiomyocyte ferroptosis by Fer-1 exerted superior cardioprotective effects against the NAT10-induced exacerbation of post-I/R cardiac damage than the inhibition of apoptosis by emricasan. Mechanistically, NAT10 induced the ac4C modification of Mybbp1a, increasing its stability, which in turn activated p53 and subsequently repressed the transcription of the anti-ferroptotic gene SLC7A11. Moreover, knockdown of Mybbp1a partially abolished the detrimental effects of NAT10 overexpression on cardiomyocyte ferroptosis and cardiac I/R injury. Collectively, our study revealed that p53 and NAT10 interdependently cooperate to form a positive feedback loop that promotes cardiomyocyte ferroptosis to exacerbate cardiac I/R injury, suggesting that targeting the NAT10/Mybbp1a/p53 axis may be a novel approach for treating cardiac I/R.

Corosolic acid delivered by exosomes from Eriobotrya japonica decreased pancreatic cancer cell proliferation and invasion by inducing SAT1-mediated ferroptosis.

BACKGROUND: In this study, we investigated whether Exo regulate the proliferation and invasion of PC. METHODS: In this study, we isolated the Eriobotrya japonica Exo using Ultra-high speed centrifugal method. Mass spectrum were used for Exo active components analysis. PC (Capan-1 and Bxpc-3) cells proliferation, migration, and apoptosis were detected using CCK8, ethynyldeoxyuridine, transwell, wound healing, and flow cytometry analyses. We also constructed a lung metastatic mouse model and subcutaneous tumor model to illustrate the regulation effect of Exo or active components. Proteomics were used to reveal the regulatory mechanism responsible for the observed effects. RESULTS: We isolated Eriobotrya japonica Exo and found that Exo treatment significantly suppressed cell migration and proliferation in both in vivo and in vitro using Capan-1. Mass spectrum for Exo active components analysis found that Exo contains high amounts of corosolic acid (CRA). The further study found that CRA treatment inhibit the proliferation, migration, and increased cell death of both Capan-1 and Bxpc-3 cells in a concentration-dependent manner. In vivo experiments confirmed that CRA inhibited pulmonary metastasis by decreasing the number of metastatic foci. Cell proteomics analysis showed that CRA treatment induced spermidine/spermine N1-acetyltransferase 1 (SAT1)-dependent ferroptosis. Treatment with the ferroptosis suppressor ferrostatin-1 significantly reversed CRA-induced cell apoptosis. CONCLUSION: The data suggested that corosolic acid delivered by exosomes from Eriobotrya japonica decreased pancreatic cancer cell proliferation and invasion by inducing SAT1-mediated ferroptosis.

Activation of polyamine catabolism promotes glutamine metabolism and creates a targetable vulnerability in lung cancer.

Polyamines are a class of small polycationic alkylamines that play essential roles in both normal and cancer cell growth. Polyamine metabolism is frequently dysregulated and considered a therapeutic target in cancer. However, targeting polyamine metabolism as monotherapy often exhibits limited efficacy, and the underlying mechanisms are incompletely understood. Here we report that activation of polyamine catabolism promotes glutamine metabolism, leading to a targetable vulnerability in lung cancer. Genetic and pharmacological activation of spermidine/spermine N1-acetyltransferase 1 (SAT1), the rate-limiting enzyme of polyamine catabolism, enhances the conversion of glutamine to glutamate and subsequent glutathione (GSH) synthesis. This metabolic rewiring ameliorates oxidative stress to support lung cancer cell proliferation and survival. Simultaneous glutamine limitation and SAT1 activation result in ROS accumulation, growth inhibition, and cell death. Importantly, pharmacological inhibition of either one of glutamine transport, glutaminase, or GSH biosynthesis in combination with activation of polyamine catabolism synergistically suppresses lung cancer cell growth and xenograft tumor formation. Together, this study unveils a previously unappreciated functional interconnection between polyamine catabolism and glutamine metabolism and establishes cotargeting strategies as potential therapeutics in lung cancer.

The MUC1-HIF-1α signaling axis regulates pancreatic cancer pathogenesis through polyamine metabolism remodeling.

Dysregulation of polyamine metabolism has been implicated in cancer initiation and progression; however, the mechanism of polyamine dysregulation in cancer is not fully understood. In this study, we investigated the role of MUC1, a mucin protein overexpressed in pancreatic cancer, in regulating polyamine metabolism. Utilizing pancreatic cancer patient data, we noted a positive correlation between MUC1 expression and the expression of key polyamine metabolism pathway genes. Functional studies revealed that knockdown of spermidine/spermine N1-acetyltransferase 1 (SAT1), a key enzyme involved in polyamine catabolism, attenuated the oncogenic functions of MUC1, including cell survival and proliferation. We further identified a regulatory axis whereby MUC1 stabilized hypoxia-inducible factor (HIF-1α), leading to increased SAT1 expression, which in turn induced carbon flux into the tricarboxylic acid cycle. MUC1-mediated stabilization of HIF-1α enhanced the promoter occupancy of the latter on SAT1 promoter and corresponding transcriptional activation of SAT1, which could be abrogated by pharmacological inhibition of HIF-1α or CRISPR/Cas9-mediated knockout of HIF1A. MUC1 knockdown caused a significant reduction in the levels of SAT1-generated metabolites, N1-acetylspermidine and N8-acetylspermidine. Given the known role of MUC1 in therapy resistance, we also investigated whether inhibiting SAT1 would enhance the efficacy of FOLFIRINOX chemotherapy. By utilizing organoid and orthotopic pancreatic cancer mouse models, we observed that targeting SAT1 with pentamidine improved the efficacy of FOLFIRINOX, suggesting that the combination may represent a promising therapeutic strategy against pancreatic cancer. This study provides insights into the interplay between MUC1 and polyamine metabolism, offering potential avenues for the development of treatments against pancreatic cancer.

Dynamics and quantitative contribution of the aminoglycoside 6'-N-acetyltransferase type Ib to amikacin resistance.

Aminoglycosides are essential components in the available armamentarium to treat bacterial infections. The surge and rapid dissemination of resistance genes strongly reduce their efficiency, compromising public health. Among the multitude of modifying enzymes that confer resistance to aminoglycosides, the aminoglycoside 6'-N-acetyltransferase type Ib [AAC(6')-Ib] is the most prevalent and relevant in the clinical setting as it can inactivate numerous aminoglycosides, such as amikacin. Although the mechanism of action, structure, and biochemical properties of the AAC(6')-Ib protein have been extensively studied, the contribution of the intracellular milieu to its activity remains unclear. In this work, we used a fluorescent-based system to quantify the number of AAC(6')-Ib per cell in Escherichia coli, and we modulated this copy number with the CRISPR interference method. These tools were then used to correlate enzyme concentrations with amikacin resistance levels. Our results show that resistance to amikacin increases linearly with a higher concentration of AAC(6')-Ib until it reaches a plateau at a specific protein concentration. In vivo imaging of this protein shows that it diffuses freely within the cytoplasm of the cell, but it tends to form inclusion bodies at higher concentrations in rich culture media. Addition of a chelating agent completely dissolves these aggregates and partially prevents the plateau in the resistance level, suggesting that AAC(6')-Ib aggregation lowers resistance to amikacin. These results provide the first step in understanding the cellular impact of each AAC(6')-Ib molecule on aminoglycoside resistance. They also highlight the importance of studying its dynamic behavior within the cell.IMPORTANCEAntibiotic resistance is a growing threat to human health. Understanding antibiotic resistance mechanisms can serve as foundation for developing innovative treatment strategies to counter this threat. While numerous studies clarified the genetics and dissemination of resistance genes and explored biochemical and structural features of resistance enzymes, their molecular dynamics and individual contribution to resistance within the cellular context remain unknown. Here, we examined this relationship modulating expression levels of aminoglycoside 6'-N-acetyltransferase type Ib, an enzyme of clinical relevance. We show a linear correlation between copy number of the enzyme per cell and amikacin resistance levels up to a threshold where resistance plateaus. We propose that at concentrations below the threshold, the enzyme diffuses freely in the cytoplasm but aggregates at the cell poles at concentrations over the threshold. This research opens promising avenues for studying enzyme solubility's impact on resistance, creating opportunities for future approaches to counter resistance.

Featured lncRNA-based signature for discriminating prognosis and progression of hepatocellular carcinoma.

Long non-coding RNAs (lncRNAs) have been implicated in carcinogenesis and progression of hepatocellular carcinoma (HCC). This study aimed to identify a robust lncRNA signature for predicting the survival of HCC patients. We performed an integrated analysis of the lncRNA expression profiling in The Cancer Genome Atlas (TCGA)-liver hepatocellular carcinoma database to identify the prognosis-related lncRNA for the HCC. The HCC cohort was randomly divided into a training set (n = 250) and a testing set (n = 113). Following a two-step screening, we identified an 18-lncRNA signature risk score. The high-risk subgroups had significantly shorter survival time than the low-risk group in both the training set (P < 0.0001) and the testing set (P = 0.005). Stratification analysis revealed that the prognostic value of the lncRNA-based signature was independent of the tumor stage and pathologic stage. The area under the receiver operating characteristic curve (AUROC) of the 18-lncRNA signature risk score was 0.826 (95%CI, 0.764-0.888), 0.817 (95%CI, 0.759-0.876), and 0.799 (95%CI, 0.731-0.867) for 1-year, 3-year, and 5-year follow-up, respectively. Bioinformatics analyses indicated that the 18 lncRNA might mediate cell cycle, DNA replication processes, and canonical cancer-related pathways, in which MCM3AP-AS1 was a potential target for HCC. In conclusion, the 18-lncRNA signature was a robust predictive biomarker for the prognosis and progression of HCC.

The Arylamine N-Acetyltransferases as Therapeutic Targets in Metabolic Diseases Associated with Mitochondrial Dysfunction.

In humans, there are two arylamine N-acetyltransferase genes that encode functional enzymes (NAT1 and NAT2) as well as one pseudogene, all of which are located together on chromosome 8. Although they were first identified by their role in the acetylation of drugs and other xenobiotics, recent studies have shown strong associations for both enzymes in a variety of diseases, including cancer, cardiovascular disease, and diabetes. There is growing evidence that this association may be causal. Consistently, NAT1 and NAT2 are shown to be required for healthy mitochondria. This review discusses the current literature on the role of both NAT1 and NAT2 in mitochondrial bioenergetics. It will attempt to relate our understanding of the evolution of the two genes with biologic function and then present evidence that several major metabolic diseases are influenced by NAT1 and NAT2. Finally, it will discuss current and future approaches to inhibit or enhance NAT1 and NAT2 activity/expression using small-molecule drugs. SIGNIFICANCE STATEMENT: The arylamine N-acetyltransferases (NATs) NAT1 and NAT2 share common features in their associations with mitochondrial bioenergetics. This review discusses mitochondrial function as it relates to health and disease, and the importance of NAT in mitochondrial function and dysfunction. It also compares NAT1 and NAT2 to highlight their functional similarities and differences. Both NAT1 and NAT2 are potential drug targets for diseases where mitochondrial dysfunction is a hallmark of onset and progression.

HTATIP2 Overexpression was Associated With a Good Prognosis in Gastric Cancer.

Introduction: The purpose of this study was to compare the transcriptomes of poorly cohesive carcinoma (PCC; diffuse-type) and well-differentiated tubular adenocarcinoma (WD; intestinal-type) using gastric cancer (GC) tissues and cell lines and to evaluate the prognostic role of HIV-1 Tat Interactive Protein 2 (HTATIP2). Materials and Methods: We performed next-generation sequencing with 8 GC surgical samples (5 WD and 3 PCC) and 3 GC cell lines (1 WD: MKN74, and 2 PCC: KATOIII and SNU601). Immunohistochemistry was used to validate HTATIP2 expression. We performed functional analysis by HTATIP2 overexpression (OE). Kaplan-Meier survival plots and the PrognoScan database were used for survival analysis. Results: The genes with significantly reduced expression in PCC versus WD (in both tissues and cell lines) were HTATIP2, ESRP1, GRHL2, ARHGEF16, CKAP2L, and ZNF724. According to immunohistochemical staining, the HTATIP2-OE group had significantly higher number of patients with early GC (EGC) (T1) (P = .024), less lymph node (LN) metastasis (P = .008), and low TNMA stage (P = .017) than HTATIP2 underexpression (UE) group. Better survival rates were confirmed in the HTATIP2 OE group by Kaplan-Meir survival and PrognoScan analysis. In vitro, HTATIP2-OE in KATO III cells caused a significant decrease in cancer cell migration and invasion. Decreased Snail and Slug expression in HTATIP2 OE cells suggested that epithelial-mesenchymal transition is involved in this process. Conclusion: HTATIP2 might be a good prognostic marker and a candidate target for GC treatment.

GCN5L1-mediated acetylation prevents Rictor degradation in cardiac cells after hypoxic stress.

Cardiomyocyte apoptosis and cardiac fibrosis are the leading causes of mortality in patients with ischemic heart disease. As such, these processes represent potential therapeutic targets to treat heart failure resulting from ischemic insult. We previously demonstrated that the mitochondrial acetyltransferase protein GCN5L1 regulates cardiomyocyte cytoprotective signaling in ischemia-reperfusion injury in vivo and hypoxia-reoxygenation injury in vitro. The current study investigated the mechanism underlying GCN5L1-mediated regulation of the Akt/mTORC2 cardioprotective signaling pathway. Rictor protein levels in cardiac tissues from human ischemic heart disease patients were significantly decreased relative to non-ischemic controls. Rictor protein levels were similarly decreased in cardiac AC16 cells following hypoxic stress, while mRNA levels remained unchanged. The reduction in Rictor protein levels after hypoxia was enhanced by the knockdown of GCN5L1, and was blocked by GCN5L1 overexpression. These findings correlated with changes in Rictor lysine acetylation, which were mediated by GCN5L1 acetyltransferase activity. Rictor degradation was regulated by proteasomal activity, which was antagonized by increased Rictor acetylation. Finally, we found that GCN5L1 knockdown restricted cytoprotective Akt signaling, in conjunction with decreased mTOR abundance and activity. In summary, these studies suggest that GCN5L1 promotes cardioprotective Akt/mTORC2 signaling by maintaining Rictor protein levels through enhanced lysine acetylation.

Influence of N-acetyltransferase 2 polymorphisms and clinical variables on liver function profile of tuberculosis patients.

BACKGROUND: Single nucleotide polymorphisms (SNPs) in the N-acetyltransferase 2 (NAT2) gene as well as several other clinical factors can contribute to the elevation of liver function test values in tuberculosis (TB) patients receiving antitubercular therapy (ATT). RESEARCH DESIGN AND METHODS: A prospective study involving dynamic monitoring of the liver function tests among 130 TB patients from baseline to 98 days post ATT initiation was undertaken to assess the influence of pharmacogenomic and clinical variables on the elevation of liver function test values. Genomic DNA was extracted from serum samples for the assessment of NAT2 SNPs. Further, within this study population, we conducted a case control study to identify the odds of developing ATT-induced drug-induced liver injury (DILI) based on NAT2 SNPs, genotype and phenotype, and clinical variables. RESULTS: NAT2 slow acetylators had higher mean [90%CI] liver function test values for 8-28 days post ATT and higher odds of developing DILI (OR: 2.73, 90%CI: 1.05-7.09) than intermediate acetylators/rapid acetylators. CONCLUSION: The current study findings provide evidence for closer monitoring among TB patients with specific NAT2 SNPs, genotype and phenotype, and clinical variables, particularly between the period of more than a week to one-month post ATT initiation for better treatment outcomes.

Long noncoding RNA MCM3AP-AS1 attenuates sepsis-induced cardiomyopathy by improving inflammation, oxidative stress, and mitochondrial function through mediating the miR-501-3p/CADM1/STAT3 axis.

Oxidative stress and inflammation are highly important for sepsis-mediated myocardial damage. The long noncoding RNA (lncRNA) MCM3AP-AS1 is involved in inflammatory diseases, but its function in acute myocardial injury during sepsis has not been fully elucidated. LPS and cecal ligation and puncture (CLP) were used to construct in vitro and in vivo sepsis-induced myocardial damage models, respectively. qRT-PCR was used to evaluate alterations in MCM3AP-AS1 and miR-501-3p alterations. After the MCM3AP-AS1 and miR-501-3p knockdown or overexpression models were established, the viability, apoptosis, inflammation, oxidative stress, and mitochondrial function of the myocardial cells were examined. Dual luciferase activity assay, RNA immunoprecipitation, and fluorescence in situ hybridization (FISH) confirmed the correlation among MCM3AP-AS1, miR-501-3p, and CADM1. Previous studies revealed that MCM3AP-AS1 was downregulated in sepsis patients, myocardial cells treated with LPS, and in the CLP mouse sepsis model, whereas miR-501-3p expression was increased. MCM3AP-AS1 overexpression hampered myocardial damage mediated by LPS and abated inflammation, oxidative stress, and mitochondrial dysfunction in myocardial cells and THP-1 cells. In contrast, MCM3AP-AS1 knockdown or miR-501-3p overexpression promoted all the effects of LPS. In vivo, MCM3AP-AS1 overexpression increased the survival rate of CLP mice; ameliorated myocardial injury; decreased the levels of TNF-α, IL-1ß, IL-6, iNOS, COX2, ICAM1, VCAM1, PGE2, and MDA; and increased the levels of SOD, GSH-PX, Nrf2, and HO-1. Mechanistic studies demonstrated that MCM3AP-AS1 acted as a competitive endogenous RNA to repress miR-501-3p, enhance CADM1 expression, and dampen STAT3/nuclear factor-kappaB (NF-κB) activation. MCM3AP-AS1 suppresses myocardial injury elicited by sepsis by mediating the miR-501-3p/CADM1/STAT3/NF-κB axis.

Deciphering the structure, function, and mechanism of lysine acetyltransferase cGNAT2 in cyanobacteria.

Lysine acetylation is a conserved regulatory posttranslational protein modification that is performed by lysine acetyltransferases (KATs). By catalyzing the transfer of acetyl groups to substrate proteins, KATs play critical regulatory roles in all domains of life; however, no KATs have yet been identified in cyanobacteria. Here, we tested all predicted KATs in the cyanobacterium Synechococcus sp. PCC 7002 (Syn7002) and demonstrated that A1596, which we named cyanobacterial Gcn5-related N-acetyltransferase (cGNAT2), can catalyze lysine acetylation in vivo and in vitro. Eight amino acid residues were identified as the key residues in the putative active site of cGNAT2, as indicated by structural simulation and site-directed mutagenesis. The loss of cGNAT2 altered both growth and photosynthetic electron transport in Syn7002. In addition, quantitative analysis of the lysine acetylome identified 548 endogenous substrates of cGNAT2 in Syn7002. We further demonstrated that cGNAT2 can acetylate NAD(P)H dehydrogenase J (NdhJ) in vivo and in vitro, with the inability to acetylate K89 residues, thus decreasing NdhJ activity and affecting both growth and electron transport in Syn7002. In summary, this study identified a KAT in cyanobacteria and revealed that cGNAT2 regulates growth and photosynthesis in Syn7002 through an acetylation-mediated mechanism.

Mechanistic plasticity in ApmA enables aminoglycoside promiscuity for resistance.

The efficacy of aminoglycoside antibiotics is waning due to the acquisition of diverse resistance mechanisms by bacteria. Among the most prevalent are aminoglycoside acetyltransferases (AACs) that inactivate the antibiotics through acetyl coenzyme A-mediated modification. Most AACs are members of the GCN5 superfamily of acyltransferases which lack conserved active site residues that participate in catalysis. ApmA is the first reported AAC belonging to the left-handed ß-helix superfamily. These enzymes are characterized by an essential active site histidine that acts as an active site base. Here we show that ApmA confers broad-spectrum aminoglycoside resistance with a molecular mechanism that diverges from other detoxifying left-handed ß-helix superfamily enzymes and canonical GCN5 AACs. We find that the active site histidine plays different functions depending on the acetyl-accepting aminoglycoside substrate. This flexibility in the mechanism of a single enzyme underscores the plasticity of antibiotic resistance elements to co-opt protein catalysts in the evolution of drug detoxification.

Expanding the phenotypic and genotypic spectrum of patients with HGSNAT-related retinopathy.

BACKGROUND: Variants in HGSNAT have historically been associated with syndromic mucopolysaccharidosis type IIIC (MPSIIIC) but more recent studies demonstrate cases of HGSNAT-related non-syndromic retinitis pigmentosa. We describe and expand the genotypic and phenotypic spectrum of this disease. MATERIALS AND METHODS: This is a retrospective, observational, case series of 11 patients with pericentral retinitis pigmentosa due to variants in HGSNAT gene without a syndromic diagnosis of MPSIIIC. We reviewed ophthalmologic data extracted from medical records, genetic testing, color fundus photos, fundus autofluorescence (FAF), and optical coherence tomography (OCT). RESULTS: Of the 11 patients, the mean age was 52 years (range: 26-78). The mean age of ophthalmologic symptoms onset was 45 years (range: 15-72). The visual acuity varied from 20/20 to 20/80 (mean 20/30 median 20/20). We described five novel variants in HGSNAT: c.715del (p.Arg239Alafs *37), c.118 G>A (p.Asp40Asn), c.1218_1220delinsTAT, c.1297A>G (p.Asn433Asp), and c.1726 G>T (p.Gly576*). CONCLUSIONS: HGSNAT has high phenotypic heterogeneity. Data from our cohort showed that all patients who had at least one variant of c.1843 G>A (p.Ala615Thr) presented with the onset of ocular symptoms after the fourth decade of life. The two patients with onset of ocular symptoms before the fourth decade did not carry this variant. This may suggest that c.1843 G>A variant is associated with a later onset of retinopathy.

Targeting Aminoglycoside Acetyltransferase Activity of Mycobacterium tuberculosis (H37Rv) Derived Eis (Enhanced Intracellular Survival) Protein with Quercetin.

Eis (Enhanced intracellular survival) protein is an aminoglycoside acetyltransferase enzyme classified under the family - GNAT (GCN5-related family of N-acetyltransferases) secreted by Mycobacterium tuberculosis (Mtb). The enzymatic activity of Eis results in the acetylation of kanamycin, thereby impairing the drug's action. In this study, we expressed and purified recombinant Eis (rEis) to determine the enzymatic activity of Eis and its potential inhibitor. Glide-enhanced precision docking was used to perform molecular docking with chosen ligands. Quercetin was found to interact Eis with a maximum binding affinity of -8.379 kcal/mol as compared to other ligands. Quercetin shows a specific interaction between the positively charged amino acid arginine in Eis and the aromatic ring of quercetin through π-cation interaction. Further, the effect of rEis was studied on the antibiotic activity of kanamycin A in the presence and absence of quercetin. It was observed that the activity of rEis aminoglycoside acetyltransferase decreased with increasing quercetin concentration. The results from the disk diffusion assay confirmed that increasing the concentration of quercetin inhibits the rEis protein activity. In conclusion, quercetin may act as a potential Eis inhibitor.

Acetylation of homogalacturonan and rhamnogalacturonan-I is catalyzed by a suite of trichome birefringence-like proteins.

Plant cell wall polysaccharides, including xylan, mannan, xyloglucan, and pectins, are often acetylated and members of the domain of unknown function 231 (DUF231)/trichome birefringence-like (TBL) family have been shown to be O-acetyltransferases mediating the acetylation of xylan, mannan, and xyloglucan. However, little is known about the O-acetyltransferases responsible for pectin acetylation. In this report, we biochemically characterized a suite of Arabidopsis DUF231/TBL proteins for their roles in pectin acetylation. We generated 24 TBL recombinant proteins in mammalian cells and demonstrated that 10 of them were able to transfer acetyl groups from acetyl-CoA onto the pectins homogalacturonan (HG) or rhamnogalacturonan-I (RG-I), and thus were named pectin O-acetyltransferase 1 to 10 (POAT1 to 10). It was found that POAT2,4,9,10 specifically acetylated HG and POAT5,6 acetylated RG-I, whereas POAT1,3,7,8 could act on both HG and RG-I. The acetylation of HG and RG-I by POATs was further corroborated by hydrolysis with pectin acetylesterases and by nuclear magnetic resonance spectroscopy. In addition, mutations of the conserved GDS and DXXH motifs in POAT3 and POAT8 were shown to lead to a loss of their ability to acetylate HG and RG-I. Furthermore, simultaneous RNA interference downregulation of POAT1,3,6,7,8 resulted in reduced cell expansion, impaired plant growth, and decreased pectin acetylation. Together, our findings indicate that these POATs are pectin O-acetyltransferases involved in acetylation of the pectin polysaccharides HG and RG-I.

The Effect of Silencing Fatty Acid Elongase 4 and 6 Genes on the Proliferation and Migration of Colorectal Cancer Cells.

Colorectal cancer (CRC) cells show some alterations in lipid metabolism, including an increased fatty acid elongation. This study was focused on investigating the effect of a small interfering RNA (siRNA)-mediated decrease in fatty acid elongation on CRC cells' survival and migration. In our study, the elongase 4 (ELOVL4) and elongase 6 (ELOVL6) genes were observed to be highly overexpressed in both the CRC tissue obtained from patients and the CRC cells cultured in vitro (HT-29 and WiDr cell lines). The use of the siRNAs for ELOVL4 and ELOVL6 reduced cancer cell proliferation and migration rates. These findings indicate that the altered elongation process decreased the survival of CRC cells, and in the future, fatty acid elongases can be potentially good targets in novel CRC therapy.

[Research progress on Mycobacterium tuberculosis acetyltransferase].

The protein acetylation of Mycobacterium tuberculosis(MTB) plays an important role in virulence, drug resistance, regulation of metabolism and host anti-tuberculosis immune response. The proteins acetylation of MTB and host protein could be induced by the MTB acetyltransferase, which is related to the occurrence, development and prognosis of tuberculosis (TB). A clear understanding of the function of MTB acetyltransferase and identification of its targeted regulatory protein acetylation modification is critical to elucidate the pathogenic mechanism and drug resistance mechanism of TB, and then this could then provide new targets for the development of anti-tuberculosis drugs. This article systematically reviewed the research progress on MTB acetyltransferase related functions, which will provide a theoretical basis for further research on its mediated protein acetylation modification, further development of new anti-tuberculosis drugs and elucidation of drug resistance mechanism.

ESCO2 promotes hypopharyngeal carcinoma progression in a STAT1-dependent manner.

BACKGROUND: The establishment of sister chromatid cohesion N-acetyltransferase 2 (ESCO2) is involved in the development of multiple malignancies. However, its role in hypopharyngeal carcinoma (HPC) progression remains uncharacterized. METHODS: This study employed bioinformatics to determine the ESCO2 expression in head and neck squamous cell carcinoma (HNSC) and normal tissues. In vitro cell proliferation, migration, apoptosis, and/or cell cycle distribution assays were used to determine the function of ESCO2 and its relationship with STAT1. Xenograft models were established in nude mice to determine ESCO2 in HPC growth in vivo. Co-immunoprecipitation/mass spectrometry (Co-IP/MS) was conducted to identify the potential ESCO2 binding partners. RESULTS: We found that ESCO2 expression was elevated in HNSC tissues, and ESCO2 depletion suppressed tumor cell migration in vitro and inhibited tumor growth in vitro and in vivo. Co-IP/MS and immunoblotting assays revealed the interaction between ESCO2 and STAT1 in HPC cells. STAT1-overexpression compromised ESCO2-mediated suppressive effects on HPC cell proliferation, viability, and migration. CONCLUSIONS: These findings suggest that ESCO2 is crucial in promoting HPC malignant progression through the STAT1 pathway and provides novel therapeutic targets for HPC treatment.