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Orphan nuclear receptor Nurr1 plays important roles in the progression of various diseases, including Parkinson's disease, neuroinflammation, Alzheimer's disease, and multiple sclerosis. It can recognize DNA as a monomer or heterodimer with retinoid X receptor α (RXRα). But the molecular mechanism of its transcriptional activity regulation is still largely unknown. Here we obtained a crystal structure of monomer Nurr1 (DNA- and ligand-binding domains, DBD and LBD) bound to NGFI-B response element. The structure exhibited two different forms with distinct DBD orientations, unveiling the conformational flexibility of nuclear receptor monomer. We then generated an integrative model of Nurr1-RXRα heterodimer. In the context of heterodimer, the structural flexibility of Nurr1 would contribute to its transcriptional activity modulation. We demonstrated that the DNA sequence may specifically modulate the transcriptional activity of Nurr1 in the absence of RXRα agonist, but the modulation can be superseded when the agonist binds to RXRα. Together, we propose a set of signaling pathways for the constitutive transcriptional activation of Nurr1 and provide molecular mechanisms for therapeutic discovery targeting Nurr1 and Nurr1-RXRα heterodimer.
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Elementos de Resposta , Receptor X Retinoide alfa , Ativação Transcricional , Receptor X Retinoide alfa/genética , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Domínios ProteicosRESUMO
Developing a straightforward and effective hydrophobic modification for metal-organic frameworks (MOFs) under mild conditions is meaningful for MOF applications. Here, a post-synthetic modification approach assisted with metal hydroxyl groups at room temperature is reported to induce hydrophobicity in the hydrophilic UiO-66. The bonding between Zr-OH in UiO-66 and n-tetradecylphosphonic acid (TDPA) is the vital force for the modifier TDPA. Superhydrophobic and superoleophilic composites were constructed for efficient oil-water separation by coating TDPA-modified UiO-66 (P-UiO-66) on commercial melamine sponges (MS) and filter papers (FP) with water contact angles of 153.2° and 155.6°, respectively. The P-UiO-66/MS composite could quickly and selectively absorb oily liquids up to 43â times its weight from water. The P-UiO-66/MS achieved continuous oil collection with high separation efficiencies (≥99.4 %). In addition, P-UiO-66/FP and P-UiO-66/MS showed high separation efficiencies for water-in-oil emulsions (≥98.5 %) and oil-in-water emulsions, respectively, with high resistance to low/high temperatures and acid/base conditions. The metal hydroxyl group-assisted post-synthetic modification strategy offers a facile and broad way to prepare hydrophobic MOFs for promising applications in environmental fields.
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Superhydrophobic metal-organic framework (MOF)-based sponges have received increasing attention in terms of treating oil-water mixtures. However, highly fluorinated substances, commonly used as modifiers to improve the hydrophobicity of MOFs, have aroused much environmental concern. Developing a green hydrophobic modification is crucial in order to prepare superhydrophobic MOF-sponge composites. Herein, we report the preparation of a porous composite sponge via a polydopamine (PDA)-assisted growth of zeolitic imidazolate frameworks (ZIF-90) and eco-friendly hydrophobic short-chain fluorinated substances (trifluoroethylamine) on a melamine formaldehyde (MF) sponge. The composite sponge (F-ZIF-90@PDA-MF) exhibited superhydrophobicity (water contact angle, 153°) and superoleophilicity (oil contact angle, 0°), which is likely due to the combination of the low surface energy brought on by the grafted CF3 groups, as well as the rough surface structures that were derived from the in situ growth of ZIF-90 nanoparticles. F-ZIF-90@PDA-MF showed an excellent adsorption capacity of 39.4-130.4 g g-1 for the different organic compounds. The adsorbed organic compounds were easily recovered by physical squeezing. Continuous and selective separation for the different oil-water mixtures was realized by employing the composite sponge as an absorbent or a filter. The separation efficiency and flux reached above 99.5% and went up to 7.1 ×105 L m-2 h-1, respectively. The results illustrate that the superhydrophobic and superoleophilic F-ZIF-90@PDA-MF sponge has potential in the field of water-oil separation, especially for the purposes of large-scale oil recovery in a water environment.
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This study aimed to elucidate the key mechanisms and effects of the functional component of green tea, epigallocatechin gallate (EGCG) on a diabetic mouse model. The detected relationship between compounds and genes recorded in the STITCH database highlighted an interaction network between the direct target genes of EGCG and the known diabetes-related genes, which was made apparent through the analysis of gene-gene interactions and signaling pathways, revealing that a key AGE-RAGE signaling pathway in diabetes was enriched in the network. By means of systematic supplementary analyses on diabetic mice, provided evidence suggested that EGCG could significantly enhance the morphology of pancreatic tissues in diabetic mice and downregulate the blood glucose level in a clear dose effect manner, and increased insulin receptor (IR), insulin receptor substrate (IRS1 and IRS2) expression in the liver. Through the detection of protein expression, EGCG was observed to possess the ability to downregulate the accumulation of AGE-RAGE in pancreatic tissues as well as in the transcription factor nuclear factor-κB (NF-κB), which represents a potentially significant method by which EGCG influences diabetes. The results of this study provided evidence indicating that EGCG can effectively improve the morphology of pancreatic tissues, but notably reduce blood glucose levels in diabetic mice, which may be related to its inhibition of AGE-RAGE signaling pathway and activation of transcription factor NF-κB pathway.
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BACKGROUND: Upper tract urinary carcinoma (UTUC) is a relatively uncommon but aggressive disease. The Ki-67 antigen is a classic marker of cellular proliferation, but there is still controversy regarding the significance and importance of Ki-67 in tumor progression. METHODS: In this study, we first detected Ki-67 expression in UTUC patients by immunohistochemistry (IHC). Subsequently, we quantitatively combined the results with those from the published literature in a meta-analysis after searching several databases. RESULTS: IHC results demonstrated that patients with muscle-invasive tumors (T2-T4) had higher Ki-67 expression than those with non-muscle-invasive tumors (Tis-T1), suggesting that high Ki-67 expression may be associated with the aggressive form of UTUC. Kaplan-Meier curves showed that patients with high Ki-67 expression had significantly poorer cancer-specific survival (CSS) and disease-free survival (DFS). Furthermore, multivariate analysis suggested that Ki-67 expression was an independent prognostic factor for CSS (hazard ratio, HR=3.196) and DFS (HR=3.517) in UTUC patients. Then, a meta-analysis of the published literature investigating Ki-67 expression and its effects on UTUC prognosis was conducted. After searching the PubMed, Medline, Embase, Cochrane Library and Scopus databases, 12 articles met the eligibility criteria for this analysis. The eligible studies included a total of 1740 patients with a mean number of 82 patients per study (range, 38-475). The combined results showed that increased Ki-67 levels were associated with poor survival and disease progression, with a pooled HR estimate of 2.081 and 2.791, respectively. In subgroup analysis, the pooled HR was statistically significant for cancer-specific survival (HR=2.276), metastasis-free survival (HR=3.008) and disease-free survival (HR=6.336). CONCLUSIONS: In conclusion, high Ki-67 expression was associated with poor survival in patients with UTUC, as well as a high risk of disease progression, although these findings need to be interpreted with caution. Large-scale, adequately designed, prospective trials are needed to further confirm the value of Ki-67 in prognosis of UTUC patients.
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Biomarcadores Tumorais/metabolismo , Antígeno Ki-67/metabolismo , Neoplasias Urológicas/metabolismo , Idoso , Progressão da Doença , Intervalo Livre de Doença , Feminino , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Masculino , Análise Multivariada , Prognóstico , Estudos Retrospectivos , Neoplasias Urológicas/patologia , Neoplasias Urológicas/cirurgiaRESUMO
We report a prototypical device of CH3NH3PbCl3 film ultraviolet photodetectors that were fabricated with a coplanar metal-semiconductor-metal Au interdigital electrode configuration. Pure phase CH3NH3PbCl3 films with a good crystallinity were formed by a hybrid sequential deposition process featured with inter-diffusion of PbCl2 and CH3NH3Cl upon annealing. The CH3NH3PbCl3 film photodetector exhibits a high responsivity of 7.56 A /W at 360 nm, a ultraviolet/visible rejection ratio (R360 nm/R500 nm) was about two orders of magnitude and fast response speed with a rising time of 170 µs and a decay time of 220 µs. All the above results demonstrate CH3NH3PbCl3 film photodetector as a competitive candidate in the application of visible blind UV detectors.
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The interface chemistry and evolution of the evaporated perovskite films on ITO, pedot/ITO, Si and glass substrates are studied. As evidenced by X-ray diffraction and X-ray photoemission spectroscopy (XPS) results, the PbI2 phase is found to be inevitably formed at the very initial growth stage, even under the conditions of a MAI-rich environment. The extremely low binding energy of adsorbed MAI particles on all the above substrates, as compared to that of PbI2 particles, is responsible for the presence of the PbI2 phase at the interface. The formation of both hole and electron barriers at the interface of PbI2/MAPbI3, as evidenced by XPS measurements, could block carrier transport into the electrode and thus deteriorate solar cell performance. This result reveals the origin of the poor performance of perovskite solar cells (PSCs) by the vacuum evaporation method, and may help to improve the performance of PSCs made using the vacuum evaporation method.
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This study examined the influence of various pretreatment methods, frying durations, and temperatures, as well as the type of frying oil, on the formation and structure of starch-lipid complexes in fried potato chips. Potato starch was processed into dough, sliced, and subjected to deep frying following various pretreatments. Structural analysis showed that steaming as a pretreatment facilitated the generation of V-type starch-lipid complexes, whereas resistant starch type III (RS3) materialized in the desiccated samples instead of the anticipated complexes. The rate of starch-lipid complex formation initially surged but subsequently declined as treatment time increased. A reduction in treatment temperature from 190 °C to 170 °C was conducive to complex formation. Moreover, the maximum relative crystallinity (19.74 %) and ΔH value (7.76 J/g) were recorded for potato starch slices pretreated by steaming and frying in palm oil. Rapeseed oil, which is rich in unsaturated fatty acids (89.98 %), inhibits complex formation. The study concludes that pretreatment methods exert a substantial effect on the formation of starch-lipid complexes and that extended frying duration and elevated temperature may reduce this formation. Oils with longer-chain fatty acids and a lower degree of unsaturation were favorable for complex formation.
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Culinária , Temperatura Alta , Solanum tuberosum , Amido , Solanum tuberosum/química , Amido/química , Lipídeos/químicaRESUMO
Curcumin and exercise have been reported to show good anti-tumour effects. However, relevant research on the combined effects of physical exercise and curcumin supplementation on cancer and the underlying mechanisms is still lacking. The current study aimed to construct an anti-breast tumour mouse model using the combined effects of curcumin treatment and swimming exercise. Transcriptomic and metabolomic techniques were used to screen for differentially expressed genes and metabolites, evaluate the anticancer effects, and analyse the molecular regulatory mechanisms related to metabolism. Observation of the mouse phenotypes, including tumour appearance, in-vivo tumour imaging, and HE staining results of pathological sections, suggested a more obvious inhibitory effect of the combination of curcumin administration and exercise intervention on breast cancer than that of a single treatment. The combination treatment group had a total of 445 differentially expressed (154 upregulated and 291 downregulated) genes. Functional enrichment analysis showed the calcium signalling pathway, Wnt signalling pathway, PI3K Akt signalling pathway, and IL-17 signalling pathway to significantly participate in the anti-breast cancer process of curcumin-exercise combination treatment. Results of the intergroup differential metabolite analysis showed that the combined effect of curcumin and exercise involves two unique pathways, namely the amino sugar and nucleotide sugar metabolism, which includes chitosan, d-glucosamine 6-phosphate, l-fucose, and N-acetyl beta-mannosamine, and the amino acid biosynthesis, which includes dl-isoleucine, dl-tyrosine, and homocysteine. Collectively, the top-ranked genes and metabolites with the highest degree of associations were further revealed by O2PLS analysis. Overall, the study helped reveal the mechanism of action of curcumin-exercise combination treatment on breast cancer at multi-omics level.
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BACKGROUND: At present, the treatment of polycythemia vera (PV) and essential thrombocythemia (ET) is still largely supportive and symptomatic. Homoharringtonine (HHT), a valid drug for treating chronic myelogenous leukemia, has shown some effect on leukemic stem cells. The aim of this study was to observe the effect of HHT on patients with high-risk PV and ET. METHODS: Patients with high-risk PV (n = 17) or ET (n = 18) who had failed or were intolerant to hydroxycarbamide or interferon-α therapy received HHT at a dose of 1.5 mg/m(2) daily by continuous infusion for 7 days every month. Hematological responses were evaluated at the 6th month after HHT therapy. RESULTS: After six courses of HHT therapy, the hematological response rates were 64.7 % (11/17) in PV and 72.2% (13/18) in ET. In PV, the single sign remission rates of constitutional symptoms, symptomatic splenomegaly, pruritus and bone pain were 70.0% (7/10), 77.8% (7/9), 50% (1/2) and 100% (3/3), respectively. The remission rates of constitutional symptoms and symptomatic splenomegaly in ET were 66.7% (6/9) and 71.4% (5/7), respectively. The rates of grade 1 granulocytopenia and thrombocytopenia were 1.8 and 0.9%, respectively. No grade 2 or over events, or pancytopenia were observed. CONCLUSIONS: Low-dose HHT alone has considerable short-term efficacy for high-risk PV/ET and may used as a second-line drug for PV/ET treatment in patients who have failed or were intolerant to hydroxycarbamide or interferon-α therapy.
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Harringtoninas/administração & dosagem , Policitemia Vera/tratamento farmacológico , Trombocitemia Essencial/tratamento farmacológico , Adulto , Idoso , Cephalotaxus/química , Relação Dose-Resposta a Droga , Feminino , Harringtoninas/efeitos adversos , Harringtoninas/química , Mepesuccinato de Omacetaxina , Humanos , Hidroxiureia/administração & dosagem , Hidroxiureia/toxicidade , Interferon-alfa/administração & dosagem , Interferon-alfa/toxicidade , Masculino , Pessoa de Meia-Idade , Policitemia Vera/patologia , Trombocitemia Essencial/patologiaRESUMO
Solitary fibrous tumor (SFT) of the central nervous system is a rare spindle cell tumor of mesenchymal origin. The present study reports the case of a 44-year-old male patient with SFT. Magnetic resonance imaging demonstrated that the majority of the intracranial tumors exhibited uneven low signals on T1-weighted imaging (T1WI) and low mixed signals on T2WI, and there was an enhancement on enhanced scanning. Furthermore, the distal part of the left occipital lobe exhibited hypersignals on T1WI and T2WI, and this was significantly enhanced following enhanced scanning. The lower part of the scalp exhibited low signals on T1WI and high signals on T2WI, and there was no notable enhancement following enhanced scanning. Magnetic resonance spectroscopy demonstrated an elevated choline/creatine peak in the solid part of the tumor. Under the microscope, the tumor exhibited characteristic 'staghorn-shaped' blood vessels. As SFT is difficult to differentially diagnose via imaging, immunohistochemical analysis of CD34, vimentin and signal transducer and activator of transcription 6 was performed for the definitive diagnosis of SFT. Of note, surgical resection was the preferred treatment for SFT; however, due to the rarity of the tumor, subsequent adjuvant therapy and prognosis require further investigation.
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Inflammatory bowel disease (IBD) is one of the most common intestinal disorders, with increasing global incidence and prevalence. Numerous therapeutic drugs are available but require intravenous administration and are associated with high toxicity and insufficient patient compliance. Here, an oral liposome that entraps the activatable corticosteroid anti-inflammatory budesonide was developed for efficacious and safe IBD therapy. The prodrug was produced via the ligation of budesonide with linoleic acid linked by a hydrolytic ester bond, which was further constrained into lipid constituents to form colloidal stable nanoliposomes (termed budsomes). Chemical modification with linoleic acid augmented the compatibility and miscibility of the resulting prodrug in lipid bilayers to provide protection from the harsh environment of the gastrointestinal tract, while liposomal nanoformulation enables preferential accumulation to inflamed vasculature. Hence, when delivered orally, budsomes exhibited high stability with low drug release in the stomach in the presence of ultra-acidic pH but released active budesonide after accumulation in inflamed intestinal tissues. Notably, oral administration of budsomes demonstrated favorable anti-colitis effect with only â¼7% mouse body weight loss, whereas at least â¼16% weight loss was observed in other treatment groups. Overall, budsomes exhibited higher therapeutic efficiency than free budesonide treatment and potently induced remission of acute colitis without any adverse side effects. These data suggest a new and reliable approach for improving the efficacy of budesonide. Our in vivo preclinical data demonstrate the safety and increased efficacy of the budsome platform for IBD treatment, further supporting clinical evaluation of this orally efficacious budesonide therapeutic.
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Colite , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Doenças Inflamatórias Intestinais , Pró-Fármacos , Animais , Camundongos , Budesonida/farmacologia , Lipossomos , Ácido Linoleico , Colite/induzido quimicamente , Colite/tratamento farmacológico , Doenças Inflamatórias Intestinais/tratamento farmacológicoAssuntos
Mesilato de Imatinib/administração & dosagem , Mesilato de Imatinib/efeitos adversos , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Relação Dose-Resposta a Droga , Feminino , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/diagnóstico por imagem , MasculinoRESUMO
Moyamoya syndrome (MMS) refers to the moyamoya vascular disease associated with various systemic diseases and conditions, including sickle cell anemia, Fanconi anemia and iron deficiency anemia. However, the association between MMS and other hemoglobinopathies is less frequently observed. MMS, like moyamoya disease, is a cerebrovascular condition that is characterized by chronic progressive stenosis or occlusion at the ends of the bilateral internal carotid arteries, anterior cerebral arteries and the beginning of the middle cerebral arteries, and is secondary to the formation of an abnormal vascular network at the base of the skull. Patients with MMS are prone to thrombosis, aneurysm and bleeding. The present study reports the case of a 43-year-old man with α-thalassemia who presented with moyamoya vessels with a ruptured aneurysm bleeding into the ventricle. α-thalassemia is considered as an extremely rare but potential cause of MMS. Since MMS is a progressive disease, early diagnosis and treatment is vital to prevent the disease from worsening.
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The present study aimed to decrease the brittleness of flaxseed oleogels based on candelilla wax (CLW) in combination with flaxseed gum (FG). Effects of flaxseed gum concentrations (0-0.4%) on the characteristics of flaxseed oleogels including oil binding capacity, textural, thermal, and rheological properties, and crystal polymorphisms were investigated. Higher concentrations (≥0.2%) of FG significantly decreased the textural parameters (e.g., hardness, fracturability) of oleogels (p < 0.05), suggesting that FG could decrease brittleness. Rheological results indicated that all flaxseed oleogels exhibited solid-like characteristics because the elastic modulus was larger than the viscous modulus. The elastic modulus of flaxseed oleogels presented a maximum value at 0.1% gum concentration. Any increase in gum concentration beyond this concentration decreased the elastic modulus. Increasing FG concentration up to 0.4% decreased the enthalpy of flaxseed oleogels during the melting process. The ß'-polymorphic form is an orthorhombic perpendicular (Oâ¥) subcell structure. Similar ß' crystal forms were observed among flaxseed oleogels, indicating that FG did not affect them negatively. The study showed that the physical properties of flaxseed oleogels based on CLW could be significantly changed by FG addition. These results provided a deeper comprehension of the novel system, which should be considered a new way to obtain healthy fats with better plasticity for food applications.
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As a subgroup of sorting nexins (SNXs) that contain regulator of G protein signaling homology (RH) domain, SNX-RH proteins, including SNX13, SNX14 and SNX25, were proposed to play bifunctional roles in protein sorting and GPCR signaling regulation. However, mechanistic details of SNX-RH proteins functioning via RH domain remain to be illustrated. Here, we delineate crystal structures of the RH domains of SNX13 and SNX25, revealing a homodimer of SNX13 RH domain mediated by unique extended α4 and α5 helices, and a thiol modulated homodimer of SNX25-RH triggered by a unique cysteine on α6 helix. Further studies showed that RH domains of SNX-RH do not possess binding capacity toward Gα subunits, owing to the lack of critical residues for interaction. Thus, this study identifies a group of novel non-canonical RH domains that can act as a dimerization module in sorting nexins, which provides structural basis for mechanism studies on SNX-RH protein functions.
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Proteínas de Ligação ao GTP , Nexinas de Classificação , Proteínas de Ligação ao GTP/metabolismo , Transporte Proteico , Transdução de Sinais , Nexinas de Classificação/química , Humanos , Multimerização Proteica , Domínios Proteicos , Compostos de Sulfidrila/químicaRESUMO
BACKGROUND: Colorectal cancer (CRC) is the third-ranked malignant tumor in the world that contributes to the death of a major population of the world. Celastrol, a bioactive natural product isolated from the medicinal plant Tripterygium wilfordii Hook F, has been proved to be an effective anti-tumor inhibitor for multiple tumors. OBJECTIVE: To reveal the therapeutic effect and underlying mechanisms of celastrol on CRC cells. METHODS: CCK-8 and clonogenic assay were used to analyze the cell proliferation in CRC cells. Flow cytometry analysis was conducted to assess the cell cycle and cell apoptosis. Wound-healing and cell invasion assay were used to evaluate the migrating and invasion capability of CRC cells. The potential antitumor mechanism of celastrol was investigated by qPCR, western blot, and confocal immunofluorescence analyses. RESULTS: Celastrol effectively inhibited CRC cell proliferation by activating caspase-dependent cell apoptosis and facilitating G1 cell cycle arrest in a dose-dependent manner, as well as cell migration and invasion by downregulating the MMP2 and MMP9. Mechanistic protein expression revealed that celastrol suppressed the expression of COX-2 by inhibiting the phosphorylation of NF-κB p65 and subsequently leading to cytoplasmic retention of p65 protein, thereby inhibiting its nuclear translocation and transcription activities. CONCLUSION: These findings indicate that celastrol is an effective inhibitor for CRC, regulating the NF-κB/COX-2 pathway, leading to the inhibition of cell proliferation characterized by cell cycle arrest and caspase-dependent apoptosis, providing a potential alternative therapeutic agent for CRC patients.
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Neoplasias Colorretais , Triterpenos , Apoptose , Linhagem Celular Tumoral , Proliferação de Células , Neoplasias Colorretais/tratamento farmacológico , Ciclo-Oxigenase 2/metabolismo , Pontos de Checagem da Fase G1 do Ciclo Celular , Humanos , NF-kappa B/metabolismo , Triterpenos Pentacíclicos/farmacologia , Transdução de Sinais , Triterpenos/farmacologia , Triterpenos/uso terapêuticoRESUMO
The identification of a novel class of shark-derived single domain antibodies, named vnarbodies that show picomolar affinities binding to the receptor binding domain (RBD) of Wuhan and Alpha, Beta, Kappa, Delta, Delta-plus, and Lambda variants, is reported. Vnarbody 20G6 and 17F6 have broad neutralizing activities against all these SARS-CoV-2 viruses as well as other sarbecoviruses, including Pangolin coronavirus and Bat coronavirus. Intranasal administration of 20G6 effectively protects mice from the challenges of SARS-CoV-2 Wuhan and Beta variants. 20G6 and 17F6 contain a unique "WXGY" motif in the complementary determining region 3 that binds to a hidden epitope on RBD, which is highly conserved in sarbecoviruses through a novel ß-sheet interaction. It is found that the S375F mutation on Omicron RBD disrupts the structure of ß-strand, thus impair the binding with 20G6. The study demonstrates that shark-derived vnarbodies offer a prophylactic and therapeutic option against most SARS-CoV-2 variants and provide insights into antibody evasion by the Omicron variant.
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COVID-19 , Tubarões , Anticorpos de Domínio Único , Animais , Camundongos , Testes de Neutralização , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus/genéticaRESUMO
Mice deficient in acyl-CoA:diacylglycerol acyltransferase 1 (DGAT1), a key enzyme in triacylglycerol (TG) biosynthesis, are resistant to high-fat (HF) diet-induced hepatic steatosis and obesity. DGAT1-deficient (Dgat1-/-) mice have no defect in quantitative absorption of dietary fat; however, they have abnormally high levels of TG stored in the cytoplasm of enterocytes, and they have a reduced postprandial triglyceridemic response. We generated mice expressing DGAT1 only in the intestine (Dgat1IntONLY) to determine whether this phenotype contributes to resistance to HF diet-induced hepatic steatosis and obesity in Dgat1-/- mice. Despite lacking DGAT1 in liver and adipose tissue, we found that Dgat1IntONLY mice are not resistant to HF diet-induced hepatic steatosis or obesity. The results presented demonstrate that intestinal DGAT1 stimulates dietary fat secretion out of enterocytes and that altering this cellular function alters the fate of dietary fat in specific tissues.
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Diacilglicerol O-Aciltransferase/metabolismo , Gorduras na Dieta/metabolismo , Fígado Gorduroso/metabolismo , Intestinos/enzimologia , Obesidade/metabolismo , Animais , Detergentes/farmacologia , Diacilglicerol O-Aciltransferase/genética , Dieta , Enterócitos/efeitos dos fármacos , Enterócitos/metabolismo , Feminino , Intestinos/citologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Polietilenoglicóis/farmacologia , Transgenes , Triglicerídeos/sangueRESUMO
Recently, we found that enterocytes dynamically store triglycerides (TGs) in cytoplasmic lipid droplets (CLDs) during dietary fat absorption. A dynamic pool of TG in the form of CLDs which expands and depletes relative to time post dietary fat challenge is present in the absorptive cells of the small intestine, enterocytes. To identify cellular factors which may play a role in the regulation of this dynamic process we investigated the expression and localization of a lipid droplet associated protein family, PAT proteins, in enterocytes of mice chronically and acutely challenged by dietary fat. We found that adipophilin and Tip47 are the only PAT genes present in mouse intestinal mucosa and both genes are present at higher levels after high-fat challenges. We found TIP47 protein present in the intestine from chow and high-fat challenged mice; however, adipophilin protein was only present after high-fat challenges. In addition, TIP47 protein level was higher after an acute than a chronic high-fat challenge whereas adipophilin protein level was higher after a chronic than an acute high-fat challenge. We co-imaged TG in CLDs using CARS microscopy and TIP47 or adipophilin using immunocytochemistry in isolated enterocytes from mice challenged chronically and acutely by high levels of dietary fat. TIP47, but not adipophilin, coats CLDs in enterocytes after an acute high-fat challenge suggesting that TIP47 plays a role in the synthesis of CLDs from newly synthesized TG at the beginning of the process of dietary fat absorption in enterocytes. Adipophilin, on the other hand, coats CLDs only in enterocytes of chronic high-fat fed mice suggesting that adipophilin may play a role in the stabilization of TG stored in CLDs in longer term. These results suggest distinct roles for TIP47 and adipophilin in dietary fat absorption.