ABSTRACT
This research presents a unique small molecule characterized by its ability to effectively disrupt RNA G-quadruplexes (G4s), which are notably more stable than their DNA counterparts. We conducted a comprehensive series of in vitro experiments to thoroughly assess the disruptive capabilities of this molecule on RNA G4s. These experiments included comparisons with established G4 stabilizers and DNA G4 disruptors, providing a multifaceted evaluation of the molecule's efficacy. Our extensive in vitro analyses demonstrated that this molecule effectively alters G4 structures and interactions with the BG4 protein, a well-recognized G4-specific antibody. These findings underscore the molecule's potential to modulate G4-protein interactions, indicating promising applications for manipulating cellular functions associated with G4 dynamics in future research.
ABSTRACT
This study was conducted to examine the effects of acupuncture on gut microbiota and expression of NLRP3 inflammasome in the colon in poststroke depression (PSD) model rats. Sprague-Dawley male rats were randomized into four groups: sham surgery group, poststroke depression group, acupuncture group, and probiotics group. Acupuncture therapy at Baihui (GV20), Shenting (GV24), bilateral Zusanli (ST36) acupoints in the acupuncture group and probiotic gavage therapy in the probiotics group were performed once per day for 2â weeks. Behaviors of depression were assessed by using weight measurements, sucrose preference test, open field test, and forced swimming test. Histopathological alterations in the colon were determined by hematoxylin-eosin staining, the expression of NLRP3/ASC/caspase-1 pathway-related proteins was analyzed by western blotting. Serum levels of IL-1ß and IL-18 were derived from ELISA. The 16S rRNA gene sequencing was performed to examine and analyze the differences of gut microbiota of rats among all groups. Acupuncture was effective to increase weight and ameliorate depressive-like behaviors in PSD rats. Acupuncture increased the diversity of gut microbiota, upregulated the abundance of Bifidobacteriaceae and Lactobacillaceae, and decreased the relative abundance of Peptostreptococcaceae, Rikenellaceae, Eggerthellaceae, and Streptococcaceae at family level. Acupuncture effectively improved the pathological changes in the colon. Meanwhile, acupuncture reduced NLRP3, ASC, caspase-1 protein expressions in the colon, and serum levels of IL-18 and IL-1ß. Acupuncture may reduce depressive-like behaviors of PSD by regulating the gut microbiota and suppressing hyperactivation of NLRP3 inflammasome in the colon. Microbiota-gut-brain axis may be an effective target pathway for acupuncture treatment of PSD.
Subject(s)
Acupuncture Therapy , Colon , Depression , Disease Models, Animal , Gastrointestinal Microbiome , Inflammasomes , NLR Family, Pyrin Domain-Containing 3 Protein , Rats, Sprague-Dawley , Animals , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Male , Acupuncture Therapy/methods , Inflammasomes/metabolism , Depression/therapy , Depression/metabolism , Depression/etiology , Colon/metabolism , Rats , Stroke/complications , Stroke/therapy , Stroke/metabolism , Stroke/psychologyABSTRACT
Pregestational diabetes, either type 1 or type 2 diabetes, induces structural birth defects including neural tube defects (NTDs) and congenital heart defects (CHDs) in human fetuses. Rodent models of type 1 and type 2 diabetic embryopathy have been established and faithfully mimic human conditions. Hyperglycemia of maternal diabetes triggers oxidative stress in the developing neuroepithelium and the embryonic heart leading to the activation of pro-apoptotic kinases and excessive cell death. Oxidative stress also activates the unfolded protein response (UPR) and endoplasmic reticulum (ER) stress. Hyperglycemia alters epigenetic landscapes by suppressing histone deacetylation, perturbing microRNA (miRNA) expression, and increasing DNA methylation. At cellular levels, besides the induction of cell apoptosis, hyperglycemia suppresses cell proliferation and induces premature senescence. Stress signaling elicited by maternal diabetes hyperglycemia disrupts cellular organelle homeostasis leading to mitochondrial dysfunction, mitochondrial dynamic alteration, and autophagy impairment. Blocking oxidative stress, kinase activation and cellular sentence ameliorates diabetic embryopathy. Deleting the mir200c gene or restoring mir322 expression abolishes maternal diabetes hyperglycemia-induced senescence and cellular stress, respectively. Both the autophagy activator trehalose and the senomorphic rapamycin can alleviate diabetic embryopathy. Thus, targeting cellular stress, miRNAs, senescence or restoring autophagy or mitochondrial fusion is a promising approach to prevent poorly controlled maternal diabetes-induced structural birth defects. In this review, we summarize the causal events in diabetic embryopathy and propose preventions for this pathological condition.
ABSTRACT
Dietary micronutrients are integral to the development and progression of constipation; however, the specific relationship between dietary copper intake and constipation has not been thoroughly investigated. This study aims to examine the correlation between dietary copper intake and constipation among U.S. adults, thereby offering novel insights and recommendations for the clinical management and prevention of constipation. Bowel health data from the National Health and Nutrition Examination Survey (NHANES) conducted between 2005 and 2010 were analyzed. Subjects' dietary information was collected through questionnaire records. Multivariate logistic regression analysis, subgroup analysis, and curve fitting analysis were used to assess the correlation between dietary copper intake and chronic constipation. After adjusting for all possible confounders, each unit increase in dietary copper intake (converted to natural logarithms) was associated with a 20% reduction in the prevalence of constipation (OR = 0.80; 95% CI 0.65-0.98; P = 0.037). The interaction P-values for all subgroups were greater than 0.05, indicating that the findings were stable and consistent across subgroups. The present study showed a significant negative association between dietary copper intake and chronic constipation in adults. This finding raises clinical and healthcare professionals' awareness of the impact of dietary trace elements on intestinal health and has important implications for the development of personalized meal plans and rational supplementation of trace copper in patients with constipation.
Subject(s)
Constipation , Copper , Nutrition Surveys , Humans , Constipation/epidemiology , Constipation/chemically induced , Copper/administration & dosage , Male , Female , Adult , Middle Aged , United States/epidemiology , Diet/adverse effects , Aged , Prevalence , Young AdultABSTRACT
Anthraquinone-fused enediynes are anticancer natural products featuring a DNA-intercalating anthraquinone moiety. Despite recent insights into anthraquinone-fused enediyne (AQE) biosynthesis, the enzymatic steps involved in anthraquinone biogenesis remain to be elucidated. Through a combination of in vitro and in vivo studies, we demonstrated that a two-enzyme system, composed of a flavin adenine dinucleotide (FAD)-dependent monooxygenase (DynE13) and a cofactor-free enzyme (DynA1), catalyzes the final steps of anthraquinone formation by converting δ-thiolactone anthracene to hydroxyanthraquinone. We showed that the three oxygen atoms in the hydroxyanthraquinone originate from molecular oxygen (O2), with the sulfur atom eliminated as H2S. We further identified the key catalytic residues of DynE13 and A1 by structural and site-directed mutagenesis studies. Our data support a catalytic mechanism wherein DynE13 installs two oxygen atoms with concurrent desulfurization and decarboxylation, whereas DynA1 acts as a cofactor-free monooxygenase, installing the final oxygen atom in the hydroxyanthraquinone. These findings establish the indispensable roles of DynE13 and DynA1 in AQE biosynthesis and unveil novel enzymatic strategies for anthraquinone formation.
ABSTRACT
Integrated application of interface engineering and vacancy engineering is a promising and effective strategy for the design and fabrication of high-performance electrocatalysts. Herein, the heterointerface catalyst with rich sulfur vacancies, vs-Ni3S2/Fe2P, was successfully designed and constructed. The strong heterointerface coupling and rich sulfur vacancies in vs-Ni3S2/Fe2P significantly optimize the electronic structure of the catalyst and synergistically improve the inherent catalytic activity. Benefiting from the optimization of the electronic structure, vs-Ni3S2/Fe2P exhibits excellent bifunctional electrocatalytic performance in alkaline electrolytes. The overpotentials for hydrogen and oxygen evolution reactions (HER and OER) are 99 and 169 mV at a current density of 10 mA cm-2, respectively. Particularly, it achieves an ultrahigh OER performance with an overpotential of 251 mV at 300 mA cm-2. Moreover, the catalyst also displays outstanding long-term durability. Density functional theory (DFT) computations reveal that the synergy of interface coupling and sulfur vacancies is crucial to optimizing the electronic structure. This study offers a hopeful pathway for the design and construction of durable and efficient electrocatalysts.
ABSTRACT
ß-ionone, a norisoprenoid, is a natural aromatic compound derived from plants, which displays various biological activities including anticancer, antioxidant and deworming properties. Due to its large biomass and strong environmental tolerance, the nonconventional oleaginous yeast Candida tropicalis was selected to efficiently synthesize ß-ionone. We initially investigated the capacity of the cytoplasm and subcellular compartments to synthesize ß-ionone independently. Subsequently, through adaptive screening of enzymes, functional identification of subcellular localization signal peptides and subcellular compartment combination strategies, a titer of 152.4 mg/L of ß-ionone was achieved. Finally, directed evolution of rate-limiting enzyme and overexpression of key enzymes were performed to enhance ß-ionone production. The resulting titer was 400.5 mg/L in shake flasks and 730 mg/L in a bioreactor. This study demonstrates the first de novo synthesis of ß-ionone in C. tropicalis, providing a novel cellular chassis for terpenoid fragrances with considerable industrial potential.
Subject(s)
Candida tropicalis , Metabolic Engineering , Norisoprenoids , Candida tropicalis/metabolism , Candida tropicalis/genetics , Metabolic Engineering/methods , Norisoprenoids/metabolism , BioreactorsABSTRACT
The effective treatment of acute lung injury (ALI) remains a significant challenge. Patients with ALI demonstrate an abundance of proinflammatory mediators in both bronchoalveolar lavage fluid (BALF) and circulating plasma. Bardoxolone methyl (BM) is a semi-synthetic triterpenoid derived from oleanolic acid, a natural product known for its ability to inhibit proinflammatory signaling. GSDMD is a signaling protein involved in pyroptosis, a form of programmed cell death. It has been reported that its upstream proteins play a role in the pathogenesis of ALI. However, there is currently no research examining whether the effect of BM on the occurrence and development of ALI is associated with changes in GSDMD protein. In this study, we prepared nanostructured lipid carriers loaded with BM and conjugated with anti-PECAM-1 antibody (PECAM@BM NLCs). PECAM@BM NLCs were designed to specifically bind to pulmonary vascular endothelial cells that highly express the PECAM-1 receptors. We also aimed to investigate the protective effects of PECAM@BM NLCs on ALI and elucidate the underlying molecular mechanisms. The results demonstrated that PECAM@BM NLCs accumulated in the lung tissues and significantly alleviated the inflammatory injury of ALI. This was evidenced by the changes in the lung wet/dry ratio, the total protein concentration, proinflammatory cytokines in BALF, and the histopathological progress. Additionally, we elucidated that PECAM@BM NLCs had the ability to inhibit the assembly of NLRP3 inflammasome and pro-caspase-1 complex, thereby suppressing the induction of pyroptosis. This mechanism resulted in the inhibition of N-terminal GSDMD expression and effectively prevented the progression of ALI.
Subject(s)
Acute Lung Injury , Lung , Nanostructures , Oleanolic Acid , Platelet Endothelial Cell Adhesion Molecule-1 , Oleanolic Acid/pharmacology , Oleanolic Acid/analogs & derivatives , Oleanolic Acid/administration & dosage , Oleanolic Acid/chemistry , Animals , Acute Lung Injury/drug therapy , Acute Lung Injury/pathology , Nanostructures/chemistry , Platelet Endothelial Cell Adhesion Molecule-1/metabolism , Lung/drug effects , Lung/metabolism , Lung/pathology , Drug Carriers/chemistry , Male , Mice , Pneumonia/drug therapy , Pneumonia/pathology , Pneumonia/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Mice, Inbred C57BL , Lipids/chemistry , Antibodies/pharmacology , Bronchoalveolar Lavage Fluid/chemistry , Humans , Drug Delivery Systems/methods , Inflammasomes/metabolism , Inflammasomes/drug effectsABSTRACT
Perillic acid has been studied as an anticancer and antimicrobial drug. Production of perillic acid has attracted considerable attention. Meanwhile, Candida tropicalis is an unconventional diploid yeast, most significantly characterized by its ability to metabolize alkanes or fatty acids for growth and proliferation. Therefore, perillic acid's precursor (L-limonene) in C. tropicalis was firstly synthesized by expressing a Mentha spicata L-limonene synthase gene, LS_Ms in this work. Expression of a gene which encoded for a truncated version of tLS_Ms increased the production of L-limonene with a 2.78-fold increase in the titer over C. tropicalis GJR-LS-01. Compartmentalized expression of the gene tLS_Ms inhibited the production of L-limonene in C. tropicalis compared to cytoplasmic expression. Cytoplasmic overexpression of seven precursor synthesis genes significantly enhanced the production of L-limonene in C. tropicalis compared to their compartmentalized expression (mitochondria or peroxisomes), which increased by 31.7-fold in C. tropicalis GJR-tLS-01. The L-limonene titer in C. tropicalis GJR-EW-tLS-04 overexpressing the mutant gene ERG20WW in the cytoplasm was significantly increased, 11.33-fold higher than the control. The titer of L-limonene for 60 g/L glucose was increased by 1.40-fold compared to the control. Finally, a Salvia miltiorrhiza cytochrome P450 enzyme gene CYP7176 and an Arabidopsis thaliana NADPH cytochrome P450 reductase gene CPR were heterologously expressed in C. tropicalis GJR-EW-tLS-04C for the synthesis of perillic acid, which reached a titer of 106.69 mg/L in a 5-L fermenter. This is the first report of de novo synthesis of perillic acid in engineered microorganisms. The results also showed that other chemicals may be efficiently produced in C. tropicalis. KEY POINTS: ⢠Key genes cytoplasmic expression was conducive to L-limonene production in C. tropicalis. ⢠Perillic acid was first synthesized de novo in engineered microorganisms. ⢠The titer of perillic acid reached 106.69 mg/L in a 5-L fermenter.
Subject(s)
Candida tropicalis , Limonene , Metabolic Engineering , Monoterpenes , Candida tropicalis/genetics , Candida tropicalis/metabolism , Metabolic Engineering/methods , Limonene/metabolism , Monoterpenes/metabolism , Mentha spicata/genetics , Mentha spicata/metabolism , Intramolecular Lyases/genetics , Intramolecular Lyases/metabolism , Intramolecular Transferases/genetics , Intramolecular Transferases/metabolism , Terpenes/metabolism , CyclohexenesABSTRACT
Tumor recurrence is a life-threatening complication after liver transplantation (LT) for hepatocellular carcinoma (HCC). Precise recurrence risk stratification before transplantation is essential for the management of recipients. Here, we aimed to establish an inflammation-related prediction model for posttransplant HCC recurrence based on pretransplant peripheral cytokine profiling. Two hundred and ninety-three patients who underwent LT in two independent medical centers were enrolled, and their pretransplant plasma samples were sent for cytokine profiling. We identified four independent risk factors, including alpha-fetoprotein, systemic immune-inflammation index, interleukin 6, and osteocalcin in the training cohort (n = 190) by COX regression analysis. A prediction model named inflammatory fingerprint (IFP) was established based on the above factors. The IFP effectively predicted posttransplant recurrence (area under the receiver operating characteristic curve [AUROC]: 0.792, C-index: 0.736). The high IFP group recipients had significantly worse 3-year recurrence-free survival rates (37.9 vs. 86.9%, p < 0.001). Simultaneous T-cell profiling revealed that recipients with high IFP were characterized by impaired T cell function. The IFP also performed well in the validation cohort (n = 103, AUROC: 0.807, C-index: 0.681). In conclusion, the IFP efficiently predicted posttransplant HCC recurrence and helped to refine pretransplant risk stratification. Impaired T cell function might be the intrinsic mechanism for the high recurrence risk of recipients in the high IFP group.
ABSTRACT
Neurotoxins pose significant challenges in defense and healthcare due to their disruptive effects on nervous tissues. Their extreme potency and enormous structural diversity have hindered the development of effective antidotes. Motivated by the properties of cell membrane-derived nanodiscs, such as their ultrasmall size, disc shape, and inherent cell membrane functions, here, we develop neuronal membrane-derived nanodiscs (denoted "Neuron-NDs") as a countermeasure nanomedicine for broad-spectrum neurotoxin detoxification. We fabricate Neuron-NDs using the plasma membrane of human SH-SY5Y neurons and demonstrate their effectiveness in detoxifying tetrodotoxin (TTX) and botulinum toxin (BoNT), two model toxins with distinct mechanisms of action. Cell-based assays confirm the ability of Neuron-NDs to inhibit TTX-induced ion channel blockage and BoNT-mediated inhibition of synaptic vesicle recycling. In mouse models of TTX and BoNT intoxication, treatment with Neuron-NDs effectively improves survival rates in both therapeutic and preventative settings. Importantly, high-dose administration of Neuron-NDs shows no observable acute toxicity in mice, indicating its safety profile. Overall, our study highlights the facile fabrication of Neuron-NDs and their broad-spectrum detoxification capabilities, offering promising solutions for neurotoxin-related challenges in biodefense and therapeutic applications.
ABSTRACT
BACKGROUND: Chitinase-3 like-protein-1 (CHI3L1) is a member of the mammalian chitinase-like proteins and elevated serum CHI3L1 level has been proved to be associated with poor prognosis in hepatocellular carcinoma (HCC). This study aimed to investigate the relationship between serum CHI3L1 levels and body composition parameters in patients with HCC after liver transplantation (LT). METHODS: This retrospective study enrolled 200 patients after LT for HCC. Blood samples were collected and serum concentrations of CHI3L1 were measured by enzyme-linked immunosorbent assay. Computer tomography (CT) were used to estimate skeletal muscle and adipose tissue mass. Spearman's rank correlation test was performed to assess associations between serum CHI3L1 levels and these body composition parameters. A Cox proportional-hazards regression model was performed to identify independent prognostic factors. Overall survival (OS) and recurrence-free survival (RFS) curves were constructed using the Kaplan-Meier method and compared by the log-rank test. RESULTS: Total 71 patients (35.5%) were diagnosed with myosteatosis according to skeletal muscle radiation attenuation (SMRA). The 5-year OS rates were 66.9% in non-myosteatosis group, significantly higher than 49.5% in myosteatosis group (p = 0.025), while the RFS of myosteatosis group (5-year RFS: 52.6%) or non-myosteatosis group (5-year RFS: 42.0%) shown no significant difference (p = 0.068). The serum CHI3L1 level were significantly negative correlated with SMRA (r = -0.3, p < 0.001). Interestingly, in patients with myosteatosis, Kaplan-Meier analysis revealed that elevated serum CHI3L1 levels were associated with worse OS (p < 0.001) and RFS (p = 0.047). However, in patients without myosteatosis, Kaplan-Meier analysis found elevated serum CHI3L1 levels were not associated with OS (p = 0.070) or RFS (p = 0.104). CONCLUSIONS: Elevated CHI3L1 was negatively correlated with SMRA, and predicted poorer prognosis in Chinese population after LT for HCC, especially in those patients with concomitant myosteatosis. Monitoring serum CHI3L1 can predict prognosis and effectively guide individual nutrition intervention.
Subject(s)
Biomarkers, Tumor , Carcinoma, Hepatocellular , Chitinase-3-Like Protein 1 , Liver Neoplasms , Humans , Chitinase-3-Like Protein 1/blood , Liver Neoplasms/blood , Liver Neoplasms/mortality , Liver Neoplasms/pathology , Male , Carcinoma, Hepatocellular/blood , Carcinoma, Hepatocellular/mortality , Carcinoma, Hepatocellular/pathology , Female , Middle Aged , Prognosis , Retrospective Studies , Biomarkers, Tumor/blood , Body Composition , Muscle, Skeletal/pathology , Muscle, Skeletal/metabolism , Muscle, Skeletal/diagnostic imaging , Liver Transplantation , Adult , Aged , Adipose Tissue/pathology , Adipose Tissue/metabolism , Kaplan-Meier Estimate , Tomography, X-Ray ComputedABSTRACT
Chemotherapy, particularly with oxaliplatin, is a key treatment for advanced gastric cancer (GC), and exosomes derived from human bone marrow mesenchymal stem cells (hBM-MSCs) play a vital role in the tumor microenvironment. The study aims to elucidate the previously unexplored role of exosomes derived from hBM-MSCs in GC tumorigenesis, especially under the influence of chemotherapy. We conducted an experimental study, utilizing miRNA sequencing and biological experiments, to analyze the tumorigenicity of exosomal miR-424-3p secreted by hBM-MSCs and its target gene RHOXF2 in GC cell lines. The results were confirmed through experimentation using a xenograft mouse model. This study demonstrated the role of hBM-MSCs in the GC microenvironment, focusing on their epithelial-mesenchymal transition (EMT) facilitation through exosomes, which led to enhanced tumorigenicity in GC cells. Intriguingly, this pro-tumor effect was abrogated when hBM-MSCs were treated with oxaliplatin. Exosomal miRNA sequencing revealed that oxaliplatin can upregulate the levels of miR-424-3p in exosomes secreted by hBM-MSCs, thereby inhibiting the EMT process in GC cells. Furthermore, miR-424-3p was identified to target and downregulate RHOXF2 expression, impeding the malignant behavior of GC cells both in vitro and in the mouse model. These findings uncover a potential hidden mechanism of oxaliplatin's anti-tumor action and propose the delivery of miR-424-3p via exosomes as a promising avenue for anti-tumor therapy.
Subject(s)
Epithelial-Mesenchymal Transition , Exosomes , Mesenchymal Stem Cells , MicroRNAs , Oxaliplatin , Stomach Neoplasms , MicroRNAs/genetics , MicroRNAs/metabolism , Humans , Oxaliplatin/pharmacology , Mesenchymal Stem Cells/metabolism , Exosomes/metabolism , Exosomes/genetics , Animals , Stomach Neoplasms/pathology , Stomach Neoplasms/genetics , Stomach Neoplasms/metabolism , Stomach Neoplasms/drug therapy , Mice , Cell Line, Tumor , Epithelial-Mesenchymal Transition/drug effects , Epithelial-Mesenchymal Transition/genetics , Up-Regulation , Gene Expression Regulation, Neoplastic/drug effects , Xenograft Model Antitumor Assays , Antineoplastic Agents/pharmacology , Tumor Microenvironment , Mice, Nude , Disease ProgressionABSTRACT
Transcriptional heterogeneity of tumor-associated macrophages (TAMs) has been investigated in individual cancers, but the extent to which these states transcend tumor types and represent a general feature of cancer remains unclear. We performed pan-cancer single-cell RNA sequencing analysis across nine cancer types and identified distinct monocyte/TAM composition patterns. Using spatial analysis from clinical study tissues, we assessed TAM functions in shaping the tumor microenvironment (TME) and influencing immunotherapy. Two specific TAM clusters (pro-inflammatory and pro-tumor) and four TME subtypes showed distinct immunological features, genomic profiles, immunotherapy responses, and cancer prognosis. Pro-inflammatory TAMs resided in immune-enriched niches with exhausted CD8+ T cells, while pro-tumor TAMs were restricted to niches associated with a T-cell-excluded phenotype and hypoxia. We developed a machine learning model to predict immune checkpoint blockade response by integrating TAMs and clinical data. Our study comprehensively characterizes the common features of TAMs and highlights their interaction with the TME.
ABSTRACT
INTRODUCTION: To examine alterations in visual acuity in patients with diabetic macular edema (DME), classified according to the TCED-HFV optical coherence tomography (OCT) system, following anti-vascular epithelial growth factor (VEGF) therapy. METHODS: The medical records of patients with DME receiving anti-VEGF therapy were retrospectively reviewed. Patients were divided into four groups according to the TCED-HFV OCT classification. Patient demographic and clinical characteristics, and best-corrected visual acuity (BCVA) before and after treatment, were compared among the groups. RESULTS: The BCVA before treatment was 0.49±0.18, 0.81±0.41, 0.83±0.41, and 0.82±0.49 in the early DME, advanced DME, severe DME, and atrophic maculopathy groups, respectively. The BCVA in the early DME group was therefore significantly lower than that in the other three groups (p = 0.042). After treatment, the BCVA improved to 0.15±0.17, 0.52±0.31, 0.62±0.32, and 0.69±0.47 in the early DME, advanced DME, severe DME, and atrophic maculopathy groups, respectively (P<0.005). There were some differences among patients in the four groups in terms of the duration of diabetes, percentage of hemoglobin A1c, and duration of hypertension. CONCLUSION: The TCED-HFV OCT classification of patients with DME is exact and functional, and can allow the severity of DME, and its response to anti-VEGF therapy, to be estimated.
ABSTRACT
Super-resolution fluorescence microscopy has emerged as a powerful tool for studying endoplasmic reticulum (ER) dynamics in living cells. However, the lack of high-brightness, high-photostability, and stable labeling probes makes long-term super-resolution imaging of the ER still challenging. Herein, we reported a surface-functionalized Halo-tag gold nanofluorescent probe (GNP-Atto565-fR8-CA) that exhibits excellent brightness, photostability, and biocompatibility. GNP-Atto565-fR8-CA can simultaneously load multiple Atto565 dye molecules, significantly improving its brightness. Modifying the cell-penetrating peptide fR8 enables GNP-Atto565-fR8-CA to be efficiently delivered into the cytoplasm, overcoming the challenge of their easy entrapment in vesicles. Fluorescent labeling of ER proteins via Halo tags enables high specificity and stable labeling of GNP-Atto565-fR8-CA to the ER. The SIM super-resolution imaging results showed that GNP-Atto565-fR8-CA can track and observe the long-term dynamic process of the ER, and can also be used for long-term super-resolution imaging of the dynamic interactions between the ER and other organelles. This work offers a practical tool to study live-cell ER ultrastructure and dynamics.
Subject(s)
Endoplasmic Reticulum , Gold , Metal Nanoparticles , Endoplasmic Reticulum/metabolism , Gold/chemistry , Humans , HeLa Cells , Metal Nanoparticles/chemistry , Microscopy, Fluorescence , Fluorescent Dyes/chemistry , Surface PropertiesABSTRACT
Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality in premature infants with no specific treatments available. We aimed to identify the molecular mechanisms underlying NEC and investigate the therapeutic effects of Bacteroides fragilis on NEC. Clinical samples of infant feces, bile acid-targeted metabolomics, pathological staining, bioinformatics analysis, NEC rat model, and co-immunoprecipitation were used to explore the pathogenesis of NEC. Taxonomic characterization of the bile salt hydrolase (bsh) gene, enzyme activity assays, 16S rRNA sequencing, and organoids were used to explore the therapeutic effects of B. fragilis on NEC-related intestinal damage. Clinical samples, NEC rat models, and in vitro experiments revealed that total bile acid increased in the blood but decreased in feces. Moreover, the levels of FXR and other bile acid metabolism-related genes were abnormal, resulting in disordered bile acid metabolism in NEC. Taurochenodeoxycholic acid accelerated NEC pathogenesis and taurodeoxycholate alleviated NEC. B. fragilis displayed bsh genes and enzyme activity and alleviated intestinal damage by restoring gut microbiota dysbiosis and bile acid metabolism abnormalities by inhibiting the FXR-NLRP3 signaling pathway. Our results provide valuable insights into the therapeutic role of B. fragilis in NEC. Administering B. fragilis may substantially alleviate intestinal damage in NEC.
Subject(s)
Amidohydrolases , Bacteroides fragilis , Bile Acids and Salts , Enterocolitis, Necrotizing , Gastrointestinal Microbiome , NLR Family, Pyrin Domain-Containing 3 Protein , Receptors, Cytoplasmic and Nuclear , Signal Transduction , Enterocolitis, Necrotizing/metabolism , Enterocolitis, Necrotizing/microbiology , Enterocolitis, Necrotizing/drug therapy , Animals , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/genetics , Bacteroides fragilis/metabolism , Bacteroides fragilis/genetics , Signal Transduction/drug effects , Bile Acids and Salts/metabolism , Rats , Receptors, Cytoplasmic and Nuclear/metabolism , Receptors, Cytoplasmic and Nuclear/genetics , Gastrointestinal Microbiome/drug effects , Amidohydrolases/metabolism , Amidohydrolases/genetics , Humans , Rats, Sprague-Dawley , Infant, Newborn , Disease Models, Animal , Male , Female , Probiotics/administration & dosage , Probiotics/pharmacology , Infant, Premature , Dysbiosis/microbiologyABSTRACT
In this study, the cellobiose 2-epimerase gene csce from Caldicellulosiruptor saccharolyticus was expressed in Escherichia coli using TB medium containing yeast extract Oxoid and tryptone Oxoid. Interesting, it was found that when the concentration of isopropyl-beta-d-thiogalactopyranoside (IPTG) and lactose was 0 (no addition), the activity of cellobiose 2-epimerase reached 5.88 U/mL. It was 3.70-fold higher than the activity observed when 1.0 mM IPTG was added. When using M9 medium without yeast extract Oxoid and tryptone Oxoid, cellobiose 2-epimerase gene could not be expressed without IPTG and lactose. However, cellobiose 2-epimerase gene could be expressed when yeast extract Oxoid or tryptone Oxoid was added, indicating that these supplements contained inducers for gene expression. In the absence of IPTG and lactose, the addition of soy peptone Angel-1 or yeast extract Angel-1 to M9 medium significantly upregulated the expression of cellobiose 2-epimerase gene in E. coli BL21 pET28a-csce, and these inductions led to higher expression levels compared to tryptone Oxoid or yeast extract Oxoid. The relative transcription level of csce was consistent with its expression level in E. coli BL21 pET28a-csce. In the medium TB without IPTG and lactose and containing yeast extract Angel-1 and soy peptone Angel-1, the activity of cellobiose 2-epimerase reached 6.88 U/mL, representing a 2.2-fold increase compared to previously reported maximum activity in E. coli. The significance of this study lies in its implications for efficient heterologous expression of recombinant enzyme proteins in E. coli without the need for IPTG and lactose addition.