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BACKGROUND AND AIMS: Ischemia-reperfusion (I/R) injury frequently occurs during liver surgery, representing a major reason for liver failure and graft dysfunction after operation. The metabolic shift from oxidative phosphorylation to glycolysis during ischemia increased glucose consumption and accelerated lactate production. We speculate that donor livers will initiate gluconeogenesis, the reverse process of glycolysis in theory, to convert noncarbohydrate carbon substrates (including lactate) to glucose to reduce the loss of hepatocellular energy and foster glycogen storage for use in the early postoperative period, thus improving post-transplant graft function. APPROACH AND RESULTS: By analyzing human liver specimens before and after hepatic I/R injury, we found that the rate-limiting enzyme of gluconeogenesis, PCK1, was significantly induced during liver I/R injury. Mouse models with liver I/R operation and hepatocytes treated with hypoxia/reoxygenation confirmed upregulation of PCK1 during I/R stimulation. Notably, high PCK1 level in human post-I/R liver specimens was closely correlated with better outcomes of liver transplantation. However, blocking gluconeogenesis with PCK1 inhibitor aggravated hepatic I/R injury by decreasing glucose level and deepening lactate accumulation, while overexpressing PCK1 did the opposite. Further mechanistic study showed that methyltransferase 3-mediated RNA N6-methyladinosine modification contributes to PCK1 upregulation during hepatic I/R injury, and hepatic-specific knockout of methyltransferase 3 deteriorates liver I/R injury through reducing the N6-methyladinosine deposition on PCK1 transcript and decreasing PCK1 mRNA export and expression level. CONCLUSIONS: Our study found that activation of the methyltransferase 3/N6-methyladinosine-PCK1-gluconeogenesis axis is required to protect against hepatic I/R injury, providing potential intervention approaches for alleviating hepatic I/R injury during liver surgery.
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BACKGROUND & AIMS: Integrin αv (ITGAV, CD51) is regarded as a key component in multiple stages of tumor progression. However, the clinical failure of cilengitide, a specific inhibitor targeting surface CD51, suggests the importance of yet-unknown mechanisms by which CD51 promotes tumor progression. METHODS: In this study, we used several hepatocellular carcinoma (HCC) cell lines and murine hepatoma cell lines. To investigate the role of CD51 on HCC progression, we used a 3D invasion assay and in vivo bioluminescence imaging. We used periostin-knockout transgenic mice to uncover the role of the tumor microenvironment on CD51 cleavage. Moreover, we used several clinically relevant HCC models, including patient-derived organoids and patient-derived xenografts, to evaluate the therapeutic efficacy of cilengitide in combination with the γ-secretase inhibitor LY3039478. RESULTS: We found that CD51 could undergo transmembrane cleavage by γ-secretase to produce a functional intracellular domain (CD51-ICD). The cleaved CD51-ICD facilitated HCC invasion and metastasis by promoting the transcription of oxidative phosphorylation-related genes. Furthermore, we identified cancer-associated fibroblast-derived periostin as the major driver of CD51 cleavage. Lastly, we showed that cilengitide-based therapy led to a dramatic therapeutic effect when supplemented with LY3039478 in both patient-derived organoid and xenograft models. CONCLUSIONS: In summary, we revealed previously unrecognized mechanisms by which CD51 is involved in HCC progression and uncovered the underlying cause of cilengitide treatment failure, as well as providing evidence supporting the translational prospects of combined CD51-targeted therapy in the clinic. IMPACT AND IMPLICATIONS: Integrin αv (CD51) is a widely recognized pro-tumoral molecule that plays a crucial role in various stages of tumor progression, making it a promising therapeutic target. However, despite early promising results, cilengitide, a specific antagonist of CD51, failed in a phase III clinical trial. This prompted further investigation into the underlying mechanisms of CD51's effects. This study reveals that the γ-secretase complex directly cleaves CD51 to produce an intracellular domain (CD51-ICD), which functions as a pro-tumoral transcriptional regulator and can bypass the inhibitory effects of cilengitide by entering the nucleus. Furthermore, the localization of CD51 in the nucleus is significantly associated with the prognosis of patients with HCC. These findings provide a theoretical basis for re-evaluating cilengitide in clinical settings and highlight the importance of identifying a more precise patient subpopulation for future clinical trials targeting CD51.
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Carcinoma Hepatocelular , Integrina alfaV , Neoplasias Hepáticas Experimentales , Neoplasias Hepáticas , Animales , Humanos , Ratones , Secretasas de la Proteína Precursora del Amiloide , Carcinoma Hepatocelular/genética , Línea Celular Tumoral , Integrina alfaV/genética , Integrina alfaV/metabolismo , Neoplasias Hepáticas/genética , Microambiente TumoralRESUMEN
Activation of hepatic stellate cells (HSCs) is a central driver of liver fibrosis. Previous investigations have identified various altered epigenetic landscapes during the cellular progression of HSC activation. N6-methyladenosine (m6A) is the most abundant internal RNA modification in eukaryotic cells and is dynamically regulated under various physiological and pathophysiological conditions. However, the functional role of Mettl3-mediated m6A in liver fibrosis remains elusive. Here, we found that the HSC-specific knockout of m6A methyltransferase Mettl3 suppressed HSC activation and significantly alleviated liver fibrosis. Multi-omics analysis of HSCs showed that Mettl3 depletion reduced m6A deposition on mRNA transcripts of Lats2 (a central player of the Hippo/YAP signaling pathway) and slowed down their degradation. Elevated Lats2 increased phosphorylation of the downstream transcription factor YAP, suppressed YAP nuclear translocation, and decreased pro-fibrotic gene expression. Overexpressing YAP mutant resistant to phosphorylation by Lats2 partially rescued the activation and pro-fibrotic gene expression of Mettl3-deficient HSCs. Our study revealed that disruption of Mettl3 in HSCs mitigated liver fibrosis by controlling the Hippo/YAP signaling pathway, providing potential therapeutic strategies to alleviate liver fibrosis by targeting epitranscriptomic machinery.
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Células Estrelladas Hepáticas , Cirrosis Hepática , Metiltransferasas , Cirrosis Hepática/genética , Metiltransferasas/deficiencia , Metiltransferasas/genética , Multiómica , Proteínas Serina-Treonina Quinasas/genética , Proteínas Supresoras de Tumor , Animales , RatonesRESUMEN
Phycobiliproteins (PBPs) are natural water-soluble pigment proteins, which constitute light-collecting antennae, and function in algae photosynthesis, existing in cyanobacteria, red algae, and cryptomonads. They are special pigment-protein complexes in algae with a unique structure and function. According to their spectral properties, PBPs can be mainly divided into three types: allophycocyanin, phycocyanin, and PE. At present, there are two main sources of PBPs: one is natural PBPs extracted from algae and the other way is recombinant PBPs which are produced in engineered microorganisms. The covalent connection between PBP and streptavidin was realized by gene fusion. The bridge cascade reaction not only improved the sensitivity of PBP as a fluorescent probe but also saved the preparation time of the probe, which expands the application range of PBPs as fluorescent probes. In addition to its function as a light-collecting antenna in photosynthesis, PBPs also have the functions of biological detection, ion detection, and fluorescence imaging. Notably, increasing studies have designed novel PBP-based far-red fluorescent proteins, which enable the tracking of gene expression and cell fate.
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Colorantes Fluorescentes , Ficobiliproteínas , FotosíntesisRESUMEN
BACKGROUND: Immune checkpoints are crucial for the maintenance of subtle balance between self-tolerance and effector immune responses, but the role of soluble immune checkpoints (sICs) in Mycobacterium tuberculosis (M. tb) infection remains unknown. We assessed the levels of multiple sICs in individuals with distinct M. tb infection status, and their dynamic changes during anti-tuberculosis treatment. METHODS: We enrolled 24 patients with pulmonary tuberculosis, among which 10 patients were diagnosed with tuberculous pleurisy (TBP), 10 individuals with latent tuberculosis infection (LTBI), and 10 healthy volunteers from Wuxi Fifth People's Hospital and Huashan Hospital between February 2019 and May 2021. Plasma concentrations of thirteen sICs were measured at enrollment and during anti-tuberculosis treatment using luminex-based multiplex assay. sICs levels in tuberculous pleural effusion (TPE) and their relations to laboratory test markers of TPE were also assessed in TBP patients. RESULTS: The circulating levels of sPD-1, sPD-L1, sCTLA-4, sBTLA, sGITR, sIDO, sCD28, sCD27 and s4-1BB were upregulated in tuberculosis patients than in healthy controls. A lower sPD-L1 level was found in LTBI individuals than in tuberculosis patients. In TBP patients, the levels of sPD-1, sPD-L2, sCD28, sCD80, sCD27, sTIM-3, sLAG-3, sBTLA, s4-1BB and sIDO increased significantly in TPE than in plasma. In TPE, sBTLA and sLAG-3 correlated positively with the adenosine deaminase level. sIDO and sCD80 correlated positively with the lactate dehydrogenase level and the percentage of lymphocytes in TPE, respectively. Meanwhile, sCD27 correlated negatively with the specific gravity and protein level in TPE. In tuberculosis patients, the circulating levels of sBTLA and sPD-L1 gradually declined during anti-tuberculosis treatment. CONCLUSIONS: We characterized the changing balance of sICs in M. tb infection. And our results revealed the relations of sICs to laboratory test markers and treatment responses in tuberculosis patients, indicating that certain sICs may serve as potential biomarkers for disease surveillance and prognosis of tuberculosis.
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Mycobacterium tuberculosis , Derrame Pleural , Tuberculosis Pleural , Antituberculosos/uso terapéutico , Biomarcadores , Humanos , Derrame Pleural/diagnóstico , Pronóstico , Tuberculosis Pleural/diagnóstico , Tuberculosis Pleural/tratamiento farmacológicoRESUMEN
Phycobiliproteins (PBPs) are colored and water-soluble biliproteins found in cyanobacteria, rhodophytes, cryptomonads and cyanelles. They are divided into three main types: allophycocyanin, phycocyanin and phycoerythrin, according to their spectral properties. There are two methods for PBPs preparation. One is the extraction and purification of native PBPs from Cyanobacteria, Cryptophyta and Rhodophyta, and the other way is the production of recombinant PBPs by heterologous hosts. Apart from their function as light-harvesting antenna in photosynthesis, PBPs can be used as food colorants, nutraceuticals and fluorescent probes in immunofluorescence analysis. An increasing number of reports have revealed their pharmaceutical potentials such as antioxidant, anti-tumor, anti-inflammatory and antidiabetic effects. The advances in PBP biogenesis make it feasible to construct novel PBPs with various activities and produce recombinant PBPs by heterologous hosts at low cost. In this review, we present a critical overview on the productions, characterization and pharmaceutical potentials of PBPs, and discuss the key issues and future perspectives on the exploration of these valuable proteins.
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Cianobacterias , Rhodophyta , Criptófitas , Cianobacterias/metabolismo , Preparaciones Farmacéuticas/metabolismo , Ficobiliproteínas , Ficoeritrina/metabolismo , Rhodophyta/metabolismoRESUMEN
BACKGROUND & AIMS: Liver fibrosis is a wound healing response that arises from various aetiologies. The intermediate filament protein Nestin has been reported to participate in maintaining tissue homeostasis during wound healing responses. However, little is known about the role Nestin plays in liver fibrosis. This study investigated the function and precise regulatory network of Nestin during liver fibrosis. METHODS: Nestin expression was assessed via immunostaining and quantitative real-time PCR (qPCR) in fibrotic/cirrhotic samples. The induction of Nestin expression by transforming growth factor beta (TGFß)-Smad2/3 signalling was investigated through luciferase reporter assays. The functional role of Nestin in hepatic stellate cells (HSCs) was investigated by examining the pathway activity of profibrogenic TGFß-Smad2/3 signalling and degradation of TGFß receptor I (TßRI) after interfering with Nestin. The in vivo effects of knocking down Nestin were examined with an adeno-associated virus vector (serotype 6, AAV6) carrying short-hairpin RNA targeting Nestin in fibrotic mouse models. RESULTS: Nestin was mainly expressed in activated HSCs and increased with the progression of liver fibrosis. The profibrogenic pathway TGFß-Smad2/3 induced Nestin expression directly. Knocking down Nestin promoted caveolin 1-mediated TßRI degradation, resulting in TGFß-Smad2/3 pathway impairment and reduced fibrosis marker expression in HSCs. In AAV6-treated murine fibrotic models, knocking down Nestin resulted in decreased levels of inflammatory infiltration, hepatocellular damage, and a reduced degree of fibrosis. CONCLUSION: The expression of Nestin in HSCs was induced by TGFß and positively correlated with the degree of liver fibrosis. Knockdown of Nestin decreased activation of the TGFß pathway and alleviated liver fibrosis both in vitro and in vivo. Our data demonstrate a novel role of Nestin in controlling HSC activation in liver fibrosis. LAY SUMMARY: Liver fibrosis has various aetiologies but represents a common process in chronic liver diseases that is associated with high morbidity and mortality. Herein, we demonstrate that the intermediate filament protein Nestin plays an essential profibrogenic role in liver fibrosis by forming a positive feedback loop with the TGFß-Smad2/3 pathway, providing a potential therapeutic target for the treatment of liver fibrosis.
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Cirrosis Hepática , Nestina/metabolismo , Receptor Tipo I de Factor de Crecimiento Transformador beta/metabolismo , Proteína Smad2/metabolismo , Proteína smad3/metabolismo , Factor de Crecimiento Transformador beta/metabolismo , Animales , Caveolina 1/metabolismo , Descubrimiento de Drogas , Perfilación de la Expresión Génica/métodos , Células Estrelladas Hepáticas/metabolismo , Células Estrelladas Hepáticas/patología , Humanos , Cirrosis Hepática/metabolismo , Cirrosis Hepática/patología , Ratones , Proteolisis/efectos de los fármacos , Transducción de Señal/efectos de los fármacosRESUMEN
The solution of the dynamic equations of the six-axis accelerometer is a prerequisite for sensor calibration, structural optimization, and practical application. However, the forward dynamic equations (FDEs) and inverse dynamic equations (IDEs) of this type of system have not been completely solved due to the strongly nonlinear coupling relationship between the inputs and outputs. This article presents a comprehensive study of the FDEs and IDEs of the six-axis accelerometer based on a parallel mechanism. Firstly, two sets of dynamic equations of the sensor are constructed based on the Newton-Euler method in the configuration space. Secondly, based on the analytical solution of the sensor branch chain length, the coordination equation between the output signals of the branch chain is constructed. The FDEs of the sensor are established by combining the coordination equations and two sets of dynamic equations. Furthermore, by introducing generalized momentum and Hamiltonian function and using Legendre transformation, the vibration differential equations (VDEs) of the sensor are derived. The VDEs and Newton-Euler equations constitute the IDEs of the system. Finally, the explicit recursive algorithm for solving the quaternion in the equation is given in the phase space. Then the IDEs are solved by substituting the quaternion into the dynamic equations in the configuration space. The predicted numerical results of the established FDEs and IDEs are verified by comparing with virtual and actual experimental data. The actual experiment shows that the relative errors of the FDEs and the IDEs constructed in this article are 2.21% and 7.65%, respectively. This research provides a new strategy for further improving the practicability of the six-axis accelerometer.
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Mesenchymal stem cells (MSCs) have been reported to exert therapeutic effects on immunoregulation, tissue repair, and regeneration from the bench to the bedside. Increasing evidence demonstrates that extracellular vesicles (EVs) derived from MSCs could contribute to these effects and are considered as a potential replacement for stem cell-based therapies. However, the efficacy and underlying mechanisms of EV-based treatment in hepatic ischemia-reperfusion injury (IRI) remain unclear. Here, we demonstrated that human umbilical cord MSC-EVs (huc-MSC-EVs) could protect against IRI-induced hepatic apoptosis by reducing the infiltration of neutrophils and alleviating oxidative stress in hepatic tissue in vivo. Meanwhile, huc-MSC-EVs reduced the respiratory burst of neutrophils and prevented hepatocytes from oxidative stress-induced cell death in vitro. Interestingly, we found that the mitochondria-located antioxidant enzyme, manganese superoxide dismutase (MnSOD), was encapsulated in huc-MSC-EVs and reduced oxidative stress in the hepatic IRI model. Knockdown of MnSOD in huc-MSCs decreased the level of MnSOD in huc-MSC-EVs and attenuated the antiapoptotic and antioxidant capacities of huc-MSC-EVs, which could be partially rescued by MnSOD mimetic manganese (III) 5,10,15,20-tetrakis (4-benzoic acid) porphyrin (MnTBAP). In summary, these findings provide new clues to reveal the therapeutic effects of huc-MSC-EVs on hepatic IRI and evaluate their preclinical application.-Yao, J., Zheng, J., Cai, J., Zeng, K., Zhou, C., Zhang, J., Li, S., Li, H., Chen, L., He, L., Chen, H., Fu, H., Zhang, Q., Chen, G., Yang, Y., Zhang, Y. Extracellular vesicles derived from human umbilical cord mesenchymal stem cells alleviate rat hepatic ischemia-reperfusion injury by suppressing oxidative stress and neutrophil inflammatory response.
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Vesículas Extracelulares/metabolismo , Inflamación/metabolismo , Hígado/irrigación sanguínea , Células Madre Mesenquimatosas/citología , Neutrófilos/metabolismo , Estrés Oxidativo , Daño por Reperfusión/prevención & control , Cordón Umbilical/citología , Animales , Células Cultivadas , Modelos Animales de Enfermedad , Humanos , Hígado/metabolismo , Masculino , Ratas , Ratas Sprague-Dawley , Estallido RespiratorioRESUMEN
BACKGROUND: Phycobiliproteins (PBPs) are light-harvesting protein found in cyanobacteria, red algae and the cryptomonads. They have been widely used as fluorescent labels in cytometry and immunofluorescence analysis. A number of PBPs has been produced in metabolically engineered Escherichia coli. However, the recombinant PBPs are incompletely chromophorylated, and the underlying mechanisms are not clear. RESULTS AND DISCUSSION: In this work, a pathway for SLA-PEB [a fusion protein of streptavidin and allophycocyanin that covalently binds phycoerythrobilin (PEB)] biosynthesis in E. coli was constructed using a single-expression plasmid strategy. Compared with a previous E. coli strain transformed with dual plasmids, the E. coli strain transformed with a single plasmid showed increased plasmid stability and produced SLA-PEB with a higher chromophorylation ratio. To achieve full chromophorylation of SLA-PEB, directed evolution was employed to improve the catalytic performance of lyase CpcS. In addition, the catalytic abilities of heme oxygenases from different cyanobacteria were investigated based on biliverdin IXα and PEB accumulation. Upregulation of the heme biosynthetic pathway genes was also carried out to increase heme availability and PEB biosynthesis in E. coli. Fed-batch fermentation was conducted for the strain V5ALD, which produced recombinant SLA-PEB with a chromophorylation ratio of 96.7%. CONCLUSION: In addition to reporting the highest chromophorylation ratio of recombinant PBPs to date, this work demonstrated strategies for improving the chromophorylation of recombinant protein, especially biliprotein with heme, or its derivatives as a prosthetic group.
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Escherichia coli/genética , Escherichia coli/metabolismo , Ficobiliproteínas/biosíntesis , Ficobiliproteínas/genética , Plásmidos/genética , Proteínas Recombinantes de Fusión/genética , Cianobacterias/metabolismo , Ingeniería Metabólica , Ficobilinas/genética , Ficocianina/genética , Ficoeritrina/genética , Estreptavidina/genéticaRESUMEN
BACKGROUND: Monocytes are the predominant innate immune cells at the early stage of Mycobacterium tuberculosis (M. tb) infection as the host defense against intracellular pathogens. Understanding the profile of different monocyte subpopulations and the dynamics of monocyte-related biomarkers may be useful for the diagnosis and prognosis of tuberculosis. METHODS: We enrolled 129 individuals comprising patients with pulmonary tuberculosis (PTB) (n = 39), tuberculous pleurisy (TBP) (n = 28), malignant pleural effusion (MPE) (n = 21), latent tuberculosis infection (LTBI) (n = 20), and healthy controls (HC) (n = 21). Surface expression of CD14, CD16, and CD163 on monocytes was detected using flow cytometry. In addition, soluble CD163 (sCD163) was determined by enzyme linked immunosorbent assay. RESULTS: Higher frequency of CD14+CD16+ (15.7% vs 7.8%, P < 0.0001) and CD14-CD16+ (5.3% vs 2.5%, P = 0.0011) monocytes and a decreased percentage of CD14+CD16- (51.0% vs 70.4%, P = 0.0110) cells was observed in PTB patients than in HCs. Moreover, PTB patients displayed a higher frequency of CD163+ cells in CD16+ monocytes than those in the HC group (40.4% vs 11.3%, P < 0.0001). The level of sCD163 was elevated in TBP patients and was higher in pleural effusion than in plasma (2116.0 ng/ml vs 1236.0 ng/ml, P < 0.0001). sCD163 levels in pleural effusion and plasma could be used to distinguish TBP from MPE patients (cut-off values: 1950.0 and 934.7 ng/ml, respectively; AUCs: 0.8418 and 0.8136, respectively). Importantly, plasma sCD163 levels in TBP patients decreased significantly after anti-TB treatment. CONCLUSIONS: Higher expression of membrane and soluble CD163 in active tuberculosis patients might provide insights regarding the pathogenesis of tuberculosis, and sCD163 may be a novel biomarker to distinguish TBP from MPE and to predict disease severity.
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Antígenos CD/análisis , Antígenos de Diferenciación Mielomonocítica/análisis , Monocitos/metabolismo , Receptores de Superficie Celular/análisis , Tuberculosis/diagnóstico , Adulto , Anciano , Antígenos CD/sangre , Antígenos CD/metabolismo , Antígenos de Diferenciación Mielomonocítica/sangre , Antígenos de Diferenciación Mielomonocítica/metabolismo , Área Bajo la Curva , Estudios de Casos y Controles , Femenino , Humanos , Inmunidad Innata , Receptores de Lipopolisacáridos/metabolismo , Masculino , Persona de Mediana Edad , Monocitos/citología , Monocitos/inmunología , Pronóstico , Curva ROC , Receptores de Superficie Celular/sangre , Receptores de Superficie Celular/metabolismo , Receptores de IgG/metabolismo , Índice de Severidad de la Enfermedad , Tuberculosis/inmunología , Tuberculosis/patología , Tuberculosis Pleural/inmunología , Tuberculosis Pleural/patología , Tuberculosis Pulmonar/inmunología , Tuberculosis Pulmonar/patologíaRESUMEN
Normal intestinal flora is widely involved in many functions of the host: nutritional metabolism; maintenance of intestinal microecological balance; regulation of intestinal endocrine function and nerve signal transduction; promotion of intestinal immune system development and maturation; inhibition of pathogenic bacteria growth and colonization, reduction of its invasion to intestinal mucosa, and so on. In recent years, more and more studies have shown that intestinal flora is closely related to the occurrence, development, and treatment of various tumors. It is indicated that recombinant phycoerythrin (RPE) has significant anti-tumor and immunomodulatory effects. However, little is known about the mechanism of the effect of oral (or intragastric) administration of RPE on gut microbiota in tumor-bearing animals. In this study, using high-throughput 16S rDNA sequencing, we examined the response of gut microbiota in H22-bearing mice to dietary RPE supplementation. The results showed that the abundance of beneficial bacteria in the mice intestinal flora decreased and that of the detrimental flora increased after inoculation with tumor cells (H22); following treatment with dietary RPE, the abundance of beneficial bacteria in the intestinal flora significantly increased and that of detrimental bacteria decreased. In this study, for the first time, it was demonstrated that dietary RPE could modulate the gut microbiota of the H22 bearing mice by increasing the abundance of beneficial bacteria and decreasing that of detrimental bacteria among intestinal bacteria, providing evidence for the mechanism by which bioactive proteins affect intestinal nutrition and disease resistance in animals.
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Carcinoma Hepatocelular/tratamiento farmacológico , Microbioma Gastrointestinal/efectos de los fármacos , Ficoeritrina/farmacología , Animales , Bacterias , Mucosa Intestinal , Intestinos/microbiología , RatonesRESUMEN
A stable fluorescent holo-ß-allophycocyanin (holo-ApcB) was produced by metabolically engineered Escherichia coli. The E. coli cells harbored two plasmids for expression of five genes that were involved in the holo-ApcB production. Response surface methodology was employed to investigate the individual and interactive effects of four variables, i.e., initial pH of culture medium, IPTG concentration, post-induction temperature, and induction start time, on holo-ApcB production by E. coli. The experimental results showed that the IPTG concentration, postinduction temperature, and induction start time had significant individual effects on holo-ApcB production. A significant interactive effect was also found between the initial pH of culture and induction start time. The maximum holo-ApcB production of 45.3 mg/L was predicted under the following optimized culture conditions: a postinduction temperature of 28.4°C, initial pH of culture of 7.3, IPTG concentration of 1.1 mM, and postinduction time of 66 min. Holo-ApcB production under the optimized culture conditions increased 5.8-fold, compared with that under the nonoptimized conditions. Response surface methodology proved to be a valuable tool for optimization of holo-ApcB production by metabolically engineered E. coli.
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Escherichia coli/metabolismo , Ingeniería Metabólica , Ficocianina/aislamiento & purificación , Medios de Cultivo , Escherichia coli/genética , Fermentación , Ficocianina/genética , Ficocianina/metabolismo , Plásmidos/genética , Plásmidos/metabolismo , TemperaturaRESUMEN
Glutamate is a major excitatory neurotransmitter present in the central nervous system. The glutamate/cystine antiporter system x c- connects the antioxidant defense with neurotransmission and behaviour. Overactivation of ionotropic glutamate receptors induces neuronal death, a pathway called excitotoxicity. Glutamate-induced oxidative stress is a major contributor to neurodegenerative diseases including cerebral ischemia, Alzheimer's and Huntington's disease. Curcuma has a wide spectrum of biological activities regarding neuroprotection and neurocognition. By reducing the oxidative damage, curcumin attenuates a spinal cord ischemia-reperfusion injury, seizures and hippocampal neuronal loss. The rat pheochromocytoma (PC12) cell line exhibits many characteristics useful for the study of the neuroprotection and neurocognition. This investigation was carried out to determine whether the neuroprotective effects of curcumin can be observed via the glutamate-PC12 cell model. Results indicate that glutamate (20 mM) upregulated glutathione peroxidase 1, glutathione disulphide, Ca2+ influx, nitric oxide production, cytochrome c release, Bax/Bcl-2 ratio, caspase-3 activity, lactate dehydrogenase release, reactive oxygen species, H 2 O 2 , and malondialdehyde; and downregulated glutathione, glutathione reductase, superoxide dismutase and catalase, resulting in enhanced cell apoptosis. Curcumin alleviates all these adverse effects. Conclusively, curcumin can effectively protect PC12 cells against the glutamate-induced oxidative toxicity. Its mode of action involves two pathways: the glutathione-dependent nitric oxide-reactive oxygen species pathway and the mitochondria-dependent nitric oxide-reactive oxygen species pathway.
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The quasi-liquid layer (QLL), a microstructure located between ice and an adhering substrate, is critical in generating capillary pressure, which in turn influences ice adhesion behavior. This study employed molecular dynamics (MD) methods to obtain QLL thickness and utilized these measurements to estimate the adhesive strength between ice and asphalt. The research involved constructing an ice-QLL-asphalt MD model, encompassing four asphalt types and five temperature ranges from 250 K to 270 K. The QLL thickness was determined for various asphalts and temperatures using the tetrahedral order parameter gradient. Additionally, capillary pressure was calculated based on the QLL thickness and other geometric parameters obtained from the MD analysis. These findings were then compared with ice adhesion strength data acquired from pull-off tests. The results indicate that QLL thickness varies with different asphalt types and increases with temperature. At a constant temperature, the QLL thickness decreases in the order of the basal plane, primary prism plane, and secondary prism plane. Furthermore, the adhesion strength of the QLL diminishes as the temperature rises, attributed to the disruption of hydrogen bonds at lower temperatures. The greater the polarity of the asphalt's interface molecules, the stronger the adhesion strength and binding free energy. The MD simulations of the asphalt-ice interface offer insights into the atomic-scale adhesive properties of this interface, contributing to the enhancement in QLL property prediction and calibration at larger scales.
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High-viscosity modified asphalt binder (HVMA) is used widely as a polymer-modified binder in porous asphalt pavement because it can improve the cohesiveness of the asphalt mixture. However, because of the high voidage in the mixture, HVMA is vulnerable to aging induced by temperature, oxygen, water, sunlight, and other climatic conditions, which degrades the performance of pavement. The properties of asphalt binder are affected adversely by the effects of hygrothermal environments in megathermal and rainy areas. Therefore, it is essential to study the aging characteristics of HVMA under the influence of hygrothermal environments to promote its application as a high-viscosity modifier. A hygrothermal cycle aging test (HCAT) was designed to simulate the aging of HVMA when rainwater was kept inside of the pavement after rainfall in megathermal areas. One kind of base bitumen and three kinds of HVMA (referred to as SBS, A, and B, respectively) were selected in this study. Short-term aging tests, hygrothermal cycling aging tests, and long-term aging tests were performed on the base bitumen and three kinds of modified asphalt binder. Fourier-transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA), and dynamic shear rheological (DSR) tests were used to evaluate the properties of the binders on the micro and macro scales. By comparing the index variations of the four binders before and after aging, the effects of the hygrothermal environment on the properties of HVMA were studied. It was found that the effects of the hygrothermal environment expedited the decomposition of the polymer and the formation of carbonyl groups compared with the TFOT and PAV test, which TGA confirmed further. Moreover, the thermal stability of the samples was improved after HCAT. In addition, the master curves of the complex modulus showed that hygrothermal cycles made the high-temperature rutting resistance of asphalt binder increase significantly. All of the results above verified that the effect of hygrothermal cycling could accelerate the aging of HVMA and shorten its service life.
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Liver fibrosis is the integral process of chronic liver diseases caused by multiple etiologies and characterized by excessive deposition of extracellular matrix (ECM). During liver fibrosis, hepatic stellate cells (HSCs) transform into a highly proliferative, activated state, producing various cytokines, chemokines, and ECM. However, the precise mechanisms that license HSCs into the highly proliferative state remain unclear. Cyclin-dependent kinase 1 (CDK1) is a requisite event for the transition of the G1/S and G2/M phases in eukaryotic cells. In this study, it is demonstrated that CDK1 and its activating partners, Cyclin A2 and Cyclin B1, are upregulated in both liver fibrosis/cirrhosis patient specimens and the murine hepatic fibrosis models, especially in activated HSCs. In vitro, CDK1 is upregulated in spontaneously activated HSCs, and inhibiting CDK1 with specific small-molecule inhibitors (CGP74514A, RO-3306, or Purvalanol A) orshort hairpin RNAs (shRNAs) resulted in HSC apoptosis and cell cycle arrest by regulating Survivin expression. Above all, it is illustrated that increased CDK1 expression licenses the HSCs into a highly proliferative state and can serve as a potential therapeutic target in liver fibrosis.
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Proteína Quinasa CDC2 , Células Estrelladas Hepáticas , Animales , Humanos , Ratones , Apoptosis/genética , Proteína Quinasa CDC2/genética , Proteína Quinasa CDC2/metabolismo , Puntos de Control del Ciclo Celular/genética , Proliferación Celular , Fibrosis , Células Estrelladas Hepáticas/metabolismo , Células Estrelladas Hepáticas/patología , Cirrosis Hepática/genética , Cirrosis Hepática/tratamiento farmacológico , Cirrosis Hepática/metabolismoRESUMEN
The geometric structure of the BAs/WTe2heterojunction was scrutinized by employingab initiocalculations grounded on density functional theory. Multiple configurations are constructed to determine the equilibrium state of the heterojunction with optimal stability. The results show that the H1-type heterojunction with interlayer distance of 3.92 Å exhibits exceptional stability and showcases a conventional Type-II band alignment, accompanied by a direct band gap measuring 0.33 eV. By applying external electric field and introducing strain, one can efficaciously modulate both the band gap and the quantity of charge transfer in the heterojunction, accompanied by the transition of band alignment from Type-II to Type-I, which makes it expected to achieve broader applications in light-emitting diodes, laser detectors and other fields. Ultimately, the heterojunction undergoes a transformation from a semiconducting to a metallic state. Furthermore, the outstanding optical characteristics inherent to each of the two monolayers are preserved, the BAs/WTe2heterojunction also serves to enhance the absorption coefficient and spectral range of the material, particularly within the ultraviolet spectrum. It merits emphasis that the optical properties of the BAs/WTe2heterojunction are capable of modification through the imposition of external electric fields and mechanical strains, which will expand its applicability and potential for future progression within the domains of nanodevices and optoelectronic apparatus.
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Background: Long noncoding RNAs (lncRNAs) have major roles in lung adenocarcinoma (LUAD). lncRNA RP11-89K21.1 was reported to be abnormally expressed in LUAD, yet its biological functions in LUAD progression remain unclear. Materials and Methods: Forty LUAD tissues and pair-matched adjacent normal tissues were enrolled in this study. Quantitative real-time polymerase chain reaction was performed to detect the expression of lncRNA, miRNA, and mRNA in LUAD samples and cell lines. Loss-of-function assays were used to evaluate the effects of RP11-89K21.1 on LUAD cell proliferation and gefitinib resistance. Bioinformatics analysis, luciferase reporter assay, and Western blot were employed to explore the regulatory relationships among RP11-89K21.1, miR-146a/b-5p, and RHPN2. Results: RP11-89K21.1 was identified as being highly expressed in LUAD tissues and cell lines. Moreover, upregulated RP11-89K21.1 was strongly associated with unfavorable overall survival of patients with LUAD. Knockdown of RP11-89K21.1 significantly suppressed proliferation and sensitized cell to gefitinib. Mechanistically, RP11-89K21.1 could directly bind miR-146a-5p and miR-146b-5p and decrease their expression to upregulate RHPN2, and subsequently activated RhoA/ROCK pathway. More importantly, overexpression of RHPN2 reversed regulatory effects of RP11-89K21.1 knockdown on cell proliferation and gefitinib resistance. Conclusions: These observations provide new insights into the role of RP11-89K21.1 in regulating LUAD tumorigenesis, suggesting that RP11-89K21.1 is a potential therapeutic target for LUAD treatment.
Asunto(s)
Adenocarcinoma , Neoplasias Pulmonares , MicroARNs , ARN Largo no Codificante , Humanos , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , Gefitinib/farmacología , MicroARNs/genética , MicroARNs/metabolismo , Línea Celular Tumoral , Proliferación Celular/genética , Adenocarcinoma/genética , Regulación Neoplásica de la Expresión Génica , Pulmón/patología , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Movimiento Celular/genética , Proteínas Adaptadoras Transductoras de Señales/genéticaRESUMEN
OBJECTIVE: This study investigated the perioperative safety and advantages of performing a minimally invasive valve surgery (MIVS) and conducting a preliminary examination of the combined simultaneous surgery (CSS). METHODS: A total of 29 patients (16 men and 13 women; mean age, 58.41 ± 13.08 years) who underwent MIVS at our center from July 2021 to March 2022 were selected. Among them, 16 patients underwent aortic valve surgery (AVS), 13 patients underwent mitral valve surgery (MVS), and four patients additionally underwent CSS. RESULTS: The MIVS time ranged from 165 to 420 min, with a mean of 230.54 ± 54.61 min; the cardiopulmonary bypass (CPB) time ranged from 54 to 164 min, with a mean of 120.24 ± 25.98 min; the aortic cross-clamp (ACC) time ranged from 36 to 118 min, with a mean of 78.66 ± 21.01 min and an automatic heart resuscitating rate was 89.66%; the mean tracheal intubation time was 6.30 ± 3.87 h, and the median total postoperative drainage was 317.5 (35, 1470) ml. No difference was observed between preoperative and postoperative left ventricular ejection fraction (LVEF) (61.90% ± 6.28% vs. 60.21% ± 5.52%, P = 0.281). The difference in postoperative drainage (419.20 ml ± 377.20 ml vs. 588.75 ml ± 673.63 ml, P = .461), tracheal intubation time (6.66 h ± 4.27 h vs. 4.63 h ± 1.11 h, P = .359), intensive care unit (ICU) stay (3.96 ± 8.62 days vs. 2.00 ± 0.816 days, P = .658), and postoperative hospital stay (9.96 ± 8.45 days vs. 8.25 ± 1.26 days, P = .694) between MIVS and CSS was not significant. CONCLUSION: MIVS in our center may be safe and effective. Additionally, CSS may be a feasible option that could be performed after a thorough preoperative evaluation and multidisciplinary discussion.