RÉSUMÉ
The environmental threat posed by stibnite is an important geoenvironmental issue of current concern. To better understand stibnite oxidation pathways, aerobic abiotic batch experiments were conducted in aqueous solution with varying δ18OH2O value at initial neutral pH for different lengths of time (15-300 days). The sulfate oxygen and sulfur isotope compositions as well as concentrations of sulfur and antimony species were determined. The sulfur isotope fractionation factor (Δ34SSO4-stibnite) values decreased from 0.8 to -2.1 during the first 90 days, and increased to 2.6 at the 180 days, indicating the dominated intermediate sulfur species such as S2O32-, S0, and H2S (g) involved in Sb2S3 oxidation processes. The incorporation of O into sulfate derived from O2 (â¼100%) indicated that the dissociated O2 was only directly adsorbed on the stibnite-S sites in the initial stage (0-90 days). The proportion of O incorporation into sulfate from water (27%-52%) increased in the late stage (90-300 days), which suggested the oxidation mechanism changed to hydroxyl attack on stibnite-S sites promoted by nearby adsorbed O2 on stibnite-Sb sites. The exchange of oxygen between sulfite and water may also contributed to the increase of water derived O into SO42-. The new insight of stibnite oxidation pathway contributes to the understanding of sulfide oxidation mechanism and helps to interpret field data.
Sujet(s)
Oxydoréduction , Isotopes de l'oxygène , Sulfates , Isotopes du soufre , Isotopes du soufre/analyse , Sulfates/composition chimique , Isotopes de l'oxygène/analyse , Antimoine/composition chimique , Modèles chimiques , Aérobiose , Oxygène/composition chimique , Polluants chimiques de l'eau/analyse , Polluants chimiques de l'eau/composition chimique , OxydesRÉSUMÉ
Hydroxysteroid dehydrogenases (HSDHs) catalyze the oxidation/reduction of hydroxyl/keto groups of steroids with high regio- or stereoselectivity, playing an essential role in producing optically pure chemicals. In this work, a novel approach was developed to simultaneously improve the stability and activity of 7ß-hydroxysteroid dehydrogenase (7ß-HSDH) by combining B-factor analysis and computer-aided prediction. Several advantageous mutants were identified, and the most promising variant, S51Y/P202Y, exhibited 2.3-fold improvements in catalytic activity, 3.3-fold in half-life at 40°C, and 4.7-fold in catalytic efficiency (kcat/Km), respectively. Structural modeling analysis showed that the shortened reversible oxidation reaction catalytic distance and the strengthened residue interactions compared to the wild type were attributed to the improved stability and activity of the obtained mutants. To synthesize ursodeoxycholic acid cost-effectively by mutant S51Y/P202Y, a NAD-kinase was employed to facilitate the substitution of nicotinamide adenine dinucleotide phosphate (NADP+) with nicotinamide adenine dinucleotide (NAD+) in the whole-cell catalysis system. The substrate 7-ketolithocholic acid (100 mM) was converted completely in 0.5 h, achieving a space-time yield of 1,887.3 g L-1 d-1. This work provided a general target-oriented strategy for obtaining stable and highly active dehydrogenase for efficient biosynthesis. IMPORTANCE: Hydroxysteroid dehydrogenases have emerged as indispensable tools in the synthesis of steroids, bile acids, and other steroid derivatives for the pharmaceutical and chemical industries. In this study, a novel approach was developed to simultaneously improve the stability and activity of a hydroxysteroid dehydrogenase by combining B-factor analysis and computer-aided prediction. This semi-rational method was demonstrated to be highly effective for enzyme engineering. In addition, NAD kinase was introduced to convert NAD+ to NADP+ for effective coenzyme regeneration in the whole-cell multienzyme-catalyzed system. This strategy reduces the significant economic costs associated with externally supplemented cofactors in NADP-dependent biosynthetic pathways.
RÉSUMÉ
BACKGROUND: Increasing evidence has shown that environmental factors play a crucial role in the pathogenesis of periodontitis. Humans are simultaneously exposed to a variety of environmental brominated flame retardants (BFRs). However, the relationship between BFRs in periodontitis remains unclear. This study aimed to investigate the overall association between BFRs and periodontitis in a nationally representative US population and to further identify important chemicals. METHODS: Data from 3322 NHANES participants from 2009 to 2016 were used. Serum BFRs were registered, including PBDE-28, PBDE-47, PBDE-85, PBDE-99, PBDE100, PBDE-153, PBDE-154, PBDE-183, PBDE-209 and PBB-153. Survey weighted generalized logistic regression models, restricted cubic splines (RCS) were conducted to assess single BFRs exposure with periodontitis. Meanwhile, weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) were used to evaluate the overall association of BFRs mixtures with periodontitis and to identify significant chemicals. RESULTS: A total of 3322 participants were included in the study, of whom 1795 had periodontitis. After adjusting for potential confounders, multiple logistic regression analysis revealed significant positive associations between serum levels of PBDE-28, PBDE-47, PBDE-85, PBDE-99, PBDE-100, PBDE-154, PBDE-183, and PBB-153 and the risk of periodontitis (all P < 0.05). A dose-response relationship was observed for many of these BFRs, with higher quantiles associated with an increased risk of periodontitis. WQS regression identified PBDE-183 (38.60%), PBDE-153 (21.20%), PBDE-209 (14.40%), and PBDE-99 (11.90%) as the BFRs with the largest weights contributing to the overall mixture effect on periodontitis risk. BKMR analysis further supported the positive association between serum BFRs and periodontitis, with most individual BFRs showing a positive trend, except for PBDE-153. Restricted cubic spline analysis revealed a generally increasing probability of periodontitis with increasing concentrations of BFRs, albeit with some nonlinear patterns for certain compounds. CONCLUSION: In conclusion, this study provides compelling evidence of a significant association between exposure to brominated flame retardants (BFRs) and an increased risk of periodontitis in a nationally representative sample of U.S. adults. Elevated serum levels of several BFRs, including PBDE-28, PBDE-47, PBDE-85, PBDE-99, PBDE-100, PBDE-154, PBDE-183, and PBB-153, were found to be positively associated with periodontitis, exhibiting a dose-response relationship.
RÉSUMÉ
The INO80D protein, a component of the INO80 chromatin remodeling complex, plays a pivotal role in chromatin remodeling, gene expression, and DNA repair within mammalian sperm. In contrast to the condensed nuclear structure of mammalian sperm, Chinese mitten crab, Eriocheir sinensis, exhibits a distinctively decondensed sperm nucleus. The distribution and function of INO80D during the E. sinensis spermatogenesis were previously enigmatic. Our research endeavored to elucidate the distribution and function of INO80D, thereby enhancing our comprehension of sperm decondensation and the process of spermatogenesis in this species. Employing transcriptome sequencing, RT-qPCR, western blot analysis, and immunofluorescence techniques, we observed a pronounced upregulation of INO80D in the adult E. sinensis in comparison to the juvenile. The protein predominantly resides in the cellular nucleus, with high levels in spermatogonia and spermatocytes, less in stage I and III spermatids, and lowest in mature sperm. The results indicated that INO80D is initially instrumental in chromatin decondensation to facilitate gene accessibility and DNA repair during the early phases of spermatogenesis. Its role subsequently shifts to maintaining decondensed chromatin stability and genetic integrity during spermiogenesis. The sustained presence of INO80D during spermiogenesis is essential for the ultimate maturation of the decondensed sperm nucleus, imperative for preserving the unique decondensed state and the protection of genetic material in E. sinensis. Our study concludes that INO80D exerts a multifaceted influence on the spermatogenesis of E. sinensis, impacting chromatin decondensation, genetic integrity, and the regulation of early gene expression. This understanding could potentially improve crab breeding in aquaculture.
Sujet(s)
Brachyura , Assemblage et désassemblage de la chromatine , Spermatogenèse , Animaux , Spermatogenèse/génétique , Mâle , Brachyura/génétique , Spermatozoïdes/métabolisme , Noyau de la cellule/métabolisme , Noyau de la cellule/génétique , Protéines d'arthropode/génétique , Protéines d'arthropode/métabolismeRÉSUMÉ
Alzheimer's disease (AD) is an intricate neurodegenerative disorder characterized by the accumulation of misfolded proteins, including beta-amyloid (Aß) and tau, leading to cognitive decline. Despite decades of research, the precise mechanisms underlying its onset and progression remain elusive. Cathepsins are a family of lysosomal enzymes that play vital roles in cellular processes, including protein degradation and regulation of immune responses. Emerging evidence suggests that cathepsins may be involved in AD pathogenesis. Cathepsins can influence the activation of microglia and astrocytes, the resident immune cells in the brain. However, cathepsin dysfunction may lead to the accumulation of misfolded proteins, notably Aß and tau. In addition, dysregulated cathepsin activity may induce an exaggerated immune response, promoting chronic inflammation and neuronal dysfunction in patients with AD. By unraveling the classification, functions, and roles of cathepsins in AD's pathogenesis, this review sheds light on their intricate involvement in this devastating disease. Targeting cathepsin activity could be a promising and novel approach for mitigating the pathological processes that contribute to AD, providing new avenues for its treatment and prevention.
RÉSUMÉ
As nanoscale materials with the function of catalyzing substrates through enzymatic kinetics, nanozymes are regarded as potential alternatives to natural enzymes. Compared to protein-based enzymes, nanozymes exhibit attractive characteristics of low preparation cost, robust activity, flexible performance adjustment, and versatile functionalization. These advantages endow them with wide use from biochemical sensing and environmental remediation to medical theranostics. Especially in biomedical diagnosis, the feature of catalytic signal amplification provided by nanozymes makes them function as emerging labels for the detection of biomarkers and diseases, with rapid developments observed in recent years. To provide a comprehensive overview of recent progress made in this dynamic field, here an overview of biomedical diagnosis enabled by nanozymes is provided. This review first summarizes the synthesis of nanozyme materials and then discusses the main strategies applied to enhance their catalytic activity and specificity. Subsequently, representative utilization of nanozymes combined with biological elements in disease diagnosis is reviewed, including the detection of biomarkers related to metabolic, cardiovascular, nervous, and digestive diseases as well as cancers. Finally, some development trends in nanozyme-enabled biomedical diagnosis are highlighted, and corresponding challenges are also pointed out, aiming to inspire future efforts to further advance this promising field.
RÉSUMÉ
Although significant progress has been made in the development of novel targeted drugs for the treatment of acute myeloid leukemia (AML) in recent years, chemotherapy still remains the mainstay of treatment and the overall survival is poor in most patients. Here, we demonstrated the antileukemia activity of a novel small molecular compound NL101, which is formed through the modification on bendamustine with a suberanilohydroxamic acid (SAHA) radical. NL101 suppresses the proliferation of myeloid malignancy cells and primary AML cells. It induces DNA damage and caspase 3-mediated apoptosis. A genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) library screen revealed that phosphatase and tensin homologous (PTEN) gene is critical for the regulation of cell survival upon NL101 treatment. The knockout or inhibition of PTEN significantly reduced NL101-induced apoptosis in AML and myelodysplastic syndrome (MDS) cells, accompanied by the activation of protein kinase B (AKT) signaling pathway. The inhibition of mammalian target of rapamycin (mTOR) by rapamycin enhanced the sensitivity of AML cells to NL101-induced cell death. These findings uncover PTEN protein expression as a major determinant of chemosensitivity to NL101 and provide a novel strategy to treat AML with the combination of NL101 and rapamycin.
Sujet(s)
Apoptose , Clustered regularly interspaced short palindromic repeats , Leucémie aigüe myéloïde , Phosphohydrolase PTEN , Humains , Phosphohydrolase PTEN/métabolisme , Phosphohydrolase PTEN/génétique , Leucémie aigüe myéloïde/traitement médicamenteux , Leucémie aigüe myéloïde/génétique , Apoptose/effets des médicaments et des substances chimiques , Lignée cellulaire tumorale , Prolifération cellulaire/effets des médicaments et des substances chimiques , Transduction du signal , Sérine-thréonine kinases TOR/métabolisme , Protéines proto-oncogènes c-akt/métabolisme , Antinéoplasiques/pharmacologie , Antinéoplasiques/usage thérapeutique , Survie cellulaire/effets des médicaments et des substances chimiques , Résistance aux médicaments antinéoplasiques , Systèmes CRISPR-CasRÉSUMÉ
Monkeypox virus (MPXV) is a DNA virus belonging to the Orthopoxvirus genus within the Poxviridae family which can cause a zoonotic infection. The unexpected non-endemic outbreak of mpox in 2022 is considered as a new global threat. It is imperative to take proactive measures, including enhancing our understanding of MPXV's biology and pathogenesis, and developing novel antiviral strategies. The host immune responses play critical roles in defensing against MPXV infection while the virus has also evolved multiple strategies for immune escape. This review summarizes the biological features, antiviral immunity, immune evasion mechanisms, pathogenicity, and prevention strategies for MPXV.
RÉSUMÉ
A novel and facile surface molecularly imprinted polymer coated on magnetic chitosan (Fe3O4@CS@MIP) was fabricated for the selective recognition and enrichment of naringin (NRG). The Fe3O4@CS@MIP was prepared based on covalent-noncovalent synergistic imprinting strategies, utilizing 4-vinyl phenyl boric acid as covalent functional monomer, deep eutectic solvent (choline chloride/methacrylic acid [ChCl/MAA]) as non-covalent functional monomer and Fe3O4@CS nanoparticles as the magnetic support. The obtained Fe3O4@CS@MIP exhibited a uniform morphology, excellent crystallinity, outstanding magnetic properties, and high surface area. Owing to the double recognition abilities, the resultant polymer showed exceptional binding performance and rapid mass transfer in phosphate buffer (pH 7.0). The maximum binding amount of Fe3O4@CS@MIP was found to be 15.08 mg g-1, and the equilibrium adsorption could be achieved within 180 min. Moreover, they also exhibited stronger selectivity for NRG and satisfactory reusability, with only 11.0% loss after five adsorption-desorption cycles. Additionally, the Fe3O4@CS@MIP, serving as an adsorbent, presented practical application potential in the separation and enrichment of NRG from pummelo peel, with extraction efficiency in the range of 79.53% to 84.63%. This work provided a new strategy for improving the performance of MIP and contributed an attractive option for the extraction of NRG in complex samples.
RÉSUMÉ
Schistosomiasis is a tropical disease that poses a significant risk to hundreds of millions of people, yet often goes unnoticed. While praziquantel, a widely used anti-schistosome drug, has a low cost and a high cure rate, it has several drawbacks. These include ineffectiveness against schistosome larvae, reduced efficacy in young children, and emerging drug resistance. Discovering new and active anti-schistosome small molecules is therefore critical, but this process presents the challenge of low accuracy in computer-aided methods. To address this issue, we proposed GNN-DDAS, a novel deep learning framework based on graph neural networks (GNN), designed for drug discovery to identify active anti-schistosome (DDAS) small molecules. Initially, a multi-layer perceptron was used to derive sequence features from various representations of small molecule SMILES. Next, GNN was employed to extract structural features from molecular graphs. Finally, the extracted sequence and structural features were then concatenated and fed into a fully connected network to predict active anti-schistosome small molecules. Experimental results showed that GNN-DDAS exhibited superior performance compared to the benchmark methods on both benchmark and real-world application datasets. Additionally, the use of GNNExplainer model allowed us to analyze the key substructure features of small molecules, providing insight into the effectiveness of GNN-DDAS. Overall, GNN-DDAS provided a promising solution for discovering new and active anti-schistosome small molecules.
RÉSUMÉ
Here we report an enzymatic approach to synthesize N-formylneuraminic acid (Neu5Fo) containing sialosides, through a five-enzyme cascade. This method stands as an alternative to traditional chemical syntheses, aiming for precision and efficiency in generating sialosides with a tailored N-formyl group generated directly from formic acid. The newly synthesized Neu5Fo was characterized using various NMR techniques revealing a conformational equilibrium at the amide bond of the formyl group in slow exchange on the NMR time scale with a trans : cis ratio of â¼2 : 1. This work not only suggests potential for exploring the biological roles of sialosides but also points to the possibility of developing novel therapeutic agents.
RÉSUMÉ
Two new species Laccariapseudoalba and L.subroseoalbescens are described and illustrated, based on morphological characteristics and molecular phylogenetic analysis. Two new records, Laccariaumbilicata and L.yunnanensis from Thailand, are also reported. Laccariasubroseoalbescens is characterized by small basidiomata, stipe equal with an enlarged base, and nearly subclavate, pale pink to light orange. Laccariapseudoalba is characterized by pale orange to orange white pileus, has umbo when young on the pileus, and fistulose stipe of the pale to pastel red color. Phylogenetic analysis based on sequence data from rDNA internal transcribed spacer ITS1-5.8S-ITS2 rDNA (ITS), nuc 28S rDNA (28S), RNA polymerase II subunit 2 (rpb2), and translation elongation factor 1-α (tef1-α) are provided as further evidence. Molecular analysis confirms the phylogenetic positions of the two new species and two new records. The differences in characteristics of these two new species and closely related species are discussed herein.
RÉSUMÉ
Substrate access tunnel engineering is a useful strategy for enzyme modification. In this study, we improved the catalytic performance of Fe-type Nitrile hydratase (Fe-type NHase) from Pseudomonas fluorescens ZJUT001 (PfNHase) by mutating residue Q86 at the entrance of the substrate access tunnel. The catalytic activity of the mutant PfNHase-αQ86W towards benzonitrile, 2-cyanopyridine, 3-cyanopyridine, and 4-hydroxybenzonitrile was enhanced by 9.35-, 3.30-, 6.55-, and 2.71-fold, respectively, compared to that of the wild-type PfNHase (PfNHase-WT). In addition, the mutant PfNHase-αQ86W showed a catalytic efficiency (kcat/Km) towards benzonitrile 17.32-fold higher than the PfNHase-WT. Interestingly, the substrate preference of PfNHase-αQ86W shifted from aliphatic nitriles to aromatic nitrile substrates. Our analysis delved into the structural changes that led to this altered substrate preference, highlighting an expanded entrance tunnel region, theenlarged substrate-binding pocket, and the increased hydrophobic interactions between the substrate and enzyme. Molecular dynamic simulations and dynamic cross-correlation Matrix (DCCM) further supported these findings, providing a comprehensive explanation for the enhanced catalytic activity towards aromatic nitrile substrates.
RÉSUMÉ
OBJECTIVE: Oral and esophageal cancers are both upper gastrointestinal cancers that share a number of risk factors. However, most previous risk prediction models only focused on one of these two types of cancer. There is no single model that could predict both cancers simultaneously. Our objective was to develop a model specifically tailored for oral and esophageal cancers. METHODS: From 1996 to 2007, a total of 431,460 subjects aged 20 and older without a history of cancer at baseline were included and were monitored for an average duration of 7.3â¯years in Taiwan, China. A total of 704 cases of oral and esophageal cancers were detected. We utilized both univariate and multivariate COX regression for screening predictors and constructing the model. We evaluated the goodness of fit of the model based on discriminatory accuracy, Harrell's C-index, and calibration. RESULTS: Finally, we developed a Cox regression model using the twelve most significant variables: age, gender, alcohol consumption, betel chewing, smoking status, history of oral ulceration, educational level, marital status, oropharynx status, family history of nasopharyngeal carcinoma, volume ratio of blood cell, and gamma-glutamyl transferase. The AUC (area under the curve) for the complete model was 0.82. Additionally, the C-index was 0.807 (with a 95â¯% confidence interval ranging from 0.789 to 0.824) and internal calibration results demonstrated that the model performed well. CONCLUSIONS: This study identified the twelve most significant common risk factors for oral and esophageal cancers and developed a single prediction model that performs well for both types of cancer.
RÉSUMÉ
We investigated a fatal case of primary amoebic meningoencephalitis from an indoor surfing center in Taiwan. The case was detected through encephalitis syndromic surveillance. Of 56 environmental specimens, 1 was positive for Naegleria fowleri ameba. This report emphasizes the risk for N. fowleri infection from inadequately disinfected recreational waters, even indoors.
Sujet(s)
Protozooses du système nerveux central , Naegleria fowleri , Humains , Naegleria fowleri/isolement et purification , Naegleria fowleri/génétique , Taïwan/épidémiologie , Protozooses du système nerveux central/parasitologie , Protozooses du système nerveux central/diagnostic , Protozooses du système nerveux central/épidémiologie , Issue fatale , Mâle , Méningoencéphalite/parasitologie , Méningoencéphalite/diagnostic , Amibiase/diagnostic , Amibiase/parasitologie , AdulteRÉSUMÉ
BACKGROUND/AIMS: A large number of differentially expressed molecules exist in hepatocellular carcinoma (HCC), and the mechanism by which they upregulate or downregulate expression is still unclear. The purpose of this study is to explore the possible mechanism of differential expression of apoptotic chromatin condensation inducer 1 (Acin1) in HCC. MATERIALS AND METHODS: A mouse HCC model was constructed, and the expression of Acin1 in HCC was analyzed by whole transcriptome sequencing, bioinformatics analysis, and reverse transcription-quantitative polymerase chain reaction, and differentially expressed Acin1-related genes were screened to construct a protein-protein interaction and competing endogenous RNA (ceRNA) network. The microRNA (miRNAs) targeting Acin1 were further predicted using online databases and finally compared with sequencing data. RESULTS: The expression of Acin1 was significantly up-regulated in HCC compared to the paracancerous and healthy control groups (P<.001). The top 10 upregulated genes closely related to Acin1 (Slc3a2, Wiz, Srrm2, Akt1, Hnrnpu, Sap18b, Pabpn1, Ddx39b, Eif4a3, and Rnps1) were mainly involved in pathways such as messenger RNA (mRNA) surveillance, RNA transport, spliceosome, Janus kinase/ signal transducers and activators of transcription signaling, apoptosis, and ubiquitin-mediated proteolysis. The ceRNA network identified several molecules (2 long noncoding RNAs, 50 miRNAs, and 49 mRNAs) interacting with Acin1, among which miR-674-5p was highly expressed in all sample tissues, and higher than that of other differentially expressed miRNAs, and significantly downregulated in HCC. Multiple online databases such as miRWalk also predicted that miR-674-5p targets Acin1. This shows that miR-674-5p may be an important molecule for targeting Acin1. CONCLUSION: Acin1 is overexpressed in HCC, and the overexpressed Acin1 is most likely regulated by miR-674-5p and other ceRNA molecules.
Sujet(s)
Carcinome hépatocellulaire , Biologie informatique , Régulation de l'expression des gènes tumoraux , Tumeurs du foie , microARN , Régulation positive , Carcinome hépatocellulaire/génétique , Carcinome hépatocellulaire/métabolisme , Carcinome hépatocellulaire/anatomopathologie , Biologie informatique/méthodes , Tumeurs du foie/génétique , Tumeurs du foie/métabolisme , Tumeurs du foie/anatomopathologie , Animaux , Souris , microARN/génétique , microARN/métabolisme , Humains , Modèles animaux de maladie humaine , Protéines nucléaires/génétique , Protéines nucléaires/métabolisme , Analyse de profil d'expression de gènes/méthodes , Mâle , Apoptose/génétiqueRÉSUMÉ
BACKGROUND: Accurately identifying drug-target affinity (DTA) plays a pivotal role in drug screening, design, and repurposing in pharmaceutical industry. It not only reduces the time, labor, and economic costs associated with biological experiments but also expedites drug development process. However, achieving the desired level of computational accuracy for DTA identification methods remains a significant challenge. RESULTS: We proposed a novel multi-view-based graph deep model known as MvGraphDTA for DTA prediction. MvGraphDTA employed a graph convolutional network (GCN) to extract the structural features from original graphs of drugs and targets, respectively. It went a step further by constructing line graphs with edges as vertices based on original graphs of drugs and targets. GCN was also used to extract the relationship features within their line graphs. To enhance the complementarity between the extracted features from original graphs and line graphs, MvGraphDTA fused the extracted multi-view features of drugs and targets, respectively. Finally, these fused features were concatenated and passed through a fully connected (FC) network to predict DTA. CONCLUSIONS: During the experiments, we performed data augmentation on all the training sets used. Experimental results showed that MvGraphDTA outperformed the competitive state-of-the-art methods on benchmark datasets for DTA prediction. Additionally, we evaluated the universality and generalization performance of MvGraphDTA on additional datasets. Experimental outcomes revealed that MvGraphDTA exhibited good universality and generalization capability, making it a reliable tool for drug-target interaction prediction.
Sujet(s)
Apprentissage profond , Découverte de médicament/méthodes , Biologie informatique/méthodes , Préparations pharmaceutiques/composition chimique , Préparations pharmaceutiques/métabolismeRÉSUMÉ
Background: The human epidermal growth factor receptor 2 gene (HER2) has been identified as a potential therapeutic target in lung adenocarcinoma (LUAD). Non-invasive positron emission tomography (PET) imaging provides a reliable strategy for in vivo determination of HER2 expression through whole-body detection of abnormalities. The PET tracer 68Ga-NOTA-MAL-Cys-MZHER2:342 has shown promising results for HER2-positive breast and gastric cancers. This study aims to evaluate the performance of 68Ga-NOTA-MAL-Cys-MZHER2:342 in vitro and in vivo models and in clinical patients with HER2-positive LUAD. Methods: NOTA-MAL-Cys-MZHER2:342 was synthesized and labeled with 68Ga. Cell uptake, cell binding ability, and stability studies of 68Ga-NOTA-MAL-Cys-MZHER2:342 were assessed both in the Calu-3 lung cancer (LC) cell line and normal mice. In vivo assessment in tumor-bearing mice was conducted using microPET imaging and biodistribution experiments. Additionally, preliminary PET/CT imaging analysis was performed on HER2-positive LC patients. Results: 68Ga-NOTA-MAL-Cys-MZHER2:342 was prepared with a radiochemical purity (RCP) exceeding 95%. The tracer demonstrated high cell uptake in HER2-overexpressing Calu-3 cells, with an IC50 of 158.9, an adequate 1.73 nM. Good stability was exhibited both in vitro and in vivo. MicroPET imaging of Calu-3-bearing mice revealed high tumor uptake and notable tumor-to-background ratios. Positive outcomes were also observed in two HER2-positive LUAD patients. Conclusion: 68Ga-NOTA-MAL-Cys-MZHER2:342 demonstrated satisfactory stability, sensitivity, and specificity. These findings suggest that 68Ga-NOTA-MAL-Cys-MZHER2:342 PET/CT imaging provides a novel tool for non-invasive visual assessment of HER2 expression in LUAD patients.
RÉSUMÉ
Background: Methyltransferase-like 3 (METTL3), a component of the N6-methyladenosine (m6A) methyltransferase family, exhibits significant expression in HEI-OC1 cells and cochlear explants. Aminoglycoside antibiotics, known for their ototoxic potential, frequently induce irreversible auditory damage in hair cells, predominantly through oxidative stress mechanisms. However, the specific role of METTL3 in kanamycin-induced hair cell loss remains unclear. Objective: This study aims to elucidate the mechanisms by which METTL3 contributes to kanamycin-induced ototoxicity. Methods and Results: In vivo experiments demonstrated a notable reduction in METTL3 expression within cochlear explants following kanamycin administration, concomitant with the formation of stress granules (SGs). Similarly, a 24-hour kanamycin treatment led to decreased METTL3 expression and induced SG formation both in HEI-OC1 cells and neonatal cochlear explants, corroborating the in vivo observations. Lentivirus-mediated transfection was employed to overexpress and knockdown METTL3 in HEI-OC1 cells. Knockdown of METTL3 resulted in increased reactive oxygen species (ROS) levels and apoptosis induced by kanamycin, while concurrently reducing SG formation. Conversely, overexpression of METTL3 attenuated ROS generation, decreased apoptosis rates, and promoted SG formation induced by kanamycin. Therefore, METTL3-mediated SG formation presents a promising target for mitigating kanamycin-induced ROS generation and the rate of apoptosis. Conclusion: This finding indicates that METTL3-mediated SG formation holds potential in mitigating kanamycin-induced impairments in cochlear hair cells by reducing ROS formation and apoptosis rates.