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1.
Front Immunol ; 12: 670971, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34093570

RESUMO

Purpose: Chronic obstructive pulmonary disease (COPD) is a complex and persistent lung disease and lack of biomarkers. The aim of this study is to screen and verify effective biomarkers for medical practice. Methods: Differential expressed genes analysis and weighted co-expression network analysis were used to explore potential biomarker. Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and Gene set enrichment analysis (GSEA) analysis were used to explore potential mechanism. CIBERSORTx website was used to evaluate tissue-infiltrating immune cells. Enzyme-linked immunosorbent assay (ELISA) was used to assess the concentrations of the Lp-PLA2 in serum. Results: Ten genes were selected via combined DEGs and WGCNA. Furthermore, PLA2G7 was choose based on validation from independent datasets. Immune infiltrate and enrichment analysis suggest PLA2G7 may regulate immune pathway via macrophages. Next, Lp-PLA2(coded by PLA2G7 gene) level was upregulated in COPD patients, increased along with The Global Average of COPD (GOLD) stage. In additional, Lp-PLA2 level was significant correlate with FEV1/FVC, BMI, FFMI, CAT score, mMRC score and 6MWD of COPD patients. Finally, the predictive efficiency of Lp-PLA2 level (AUC:0.796) and derived nomogram model (AUC:0.884) in exercise tolerance was notably superior to that of the sit-to-stand test and traditional clinical features. Conclusion: Lp-PLA2 is a promising biomarker for COPD patients and is suitable for assessing exercise tolerance in clinical practice.

2.
Nano Lett ; 21(11): 4643-4653, 2021 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-34038136

RESUMO

DNA quantification is important for biomedical research, but the routinely used techniques rely on nucleic acid amplification which have inherent issues like cross-contamination risk and quantification bias. Here, we report a CRISPR-Cas12a-based molecular diagnostic technique for amplification-free and absolute quantification of DNA at the single-molecule level. To achieve this, we first screened out the optimal reaction parameters for high-efficient Cas12a assay, yielding over 50-fold improvement in sensitivity compared with the reported Cas12a assays. We further leveraged the microdroplet-enabled confinement effect to perform an ultralocalized droplet Cas12a assay, obtaining excellent specificity and single-molecule sensitivity. Moreover, we demonstrated its versatility and quantification capability by direct counting of diverse virus's DNAs (African swine fever virus, Epstein-Barr virus, and Hepatitis B virus) from clinical serum samples with a wide range of viral titers. Given the flexible programmability of crRNA, we envision this amplification-free technique as a versatile and quantitative platform for molecular diagnosis.

3.
ACS Nano ; 15(5): 7848-7859, 2021 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-33961413

RESUMO

Clustered, regularly interspaced short palindromic repeats (CRISPR)-based diagnoses, derived from gene-editing technology, have been exploited for less than 5 years and are now reaching the stage of precommercial use. CRISPR tools have some notable features, such as recognition at physiological temperature, excellent specificity, and high-efficiency signal amplification capabilities. These characteristics are promising for the development of next-generation diagnostic technologies. In this Perspective, we present a detailed summary of which micro/nanotechnologies play roles in the advancement of CRISPR diagnosis and how they are involved. The use of nanoprobes, nanochips, and nanodevices, microfluidic technology, lateral flow strips, etc. in CRISPR detection systems has led to new opportunities for CRISPR-based diagnosis assay development, such as achieving equipment-free detection, providing more compact detection systems, and improving sensitivity and quantitative capabilities. Although tremendous progress has been made, CRISPR diagnosis has not yet reached its full potential. We discuss upcoming opportunities and improvements and how micro/nanotechnologies will continue to play key roles.

4.
J Biol Chem ; : 100609, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33811858

RESUMO

The neurotransmitter:sodium symporter (NSS) homolog LeuT from Aquifex aeolicus has proven to be a valuable model for studying the transport mechanism of the NSS family. Crystal structures have captured LeuT in key conformations visited during the transport cycle, allowing for the construction of a nearly complete model of transport, with much of the conformational dynamics studied by computational simulations. Here, we report crystal structures of LeuT representing new intermediate conformations between the outward-facing open and occluded states. These structures, combined with binding and accessibility studies, reveal details of conformational dynamics that can follow substrate binding at the central substrate-binding site (S1) of LeuT in outward-facing states, suggesting a potential competition for direction between the outward-open and outward-occluded states at this stage during substrate transport. Our structures further support an intimate interplay between the protonation state of Glu290 and binding of Na1 that may ultimately regulate the outward-open-to-occluded transition.

5.
ACS Sens ; 6(3): 1086-1093, 2021 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-33683104

RESUMO

The outbreak of COVID-19 caused a worldwide public health crisis. Large-scale population screening is an effective means to control the spread of COVID-19. Reverse transcription-polymerase chain reaction (RT-qPCR) and serology assays are the most available techniques for SARS-CoV-2 detection; however, they suffer from either less sensitivity and accuracy or low instrument accessibility for screening. To balance the sensitivity, specificity, and test availability, here, we developed enhanced colorimetry, which is termed as a magnetic pull-down-assisted colorimetric method based on the CRISPR/Cas12a system (M-CDC), for SARS-CoV-2 detection. By this method, SARS-CoV-2 RNA from synthetic sequences and cultured viruses can be detected by the naked eye based on gold nanoparticle (AuNP) probes, with a detection limit of 50 RNA copies per reaction. With CRISPR/Cas12a-assisted detection, SARS-CoV-2 can be specifically distinguished from other closely related viruses. M-CDC was further used to analyze 41 clinical samples, whose performance was 95.12%, consistent with that of an approved Clinical RT-qPCR Diagnosis kit. The developed M-CDC method is not dependent on sophisticated instruments, which makes it potentially valuable to be applied for SARS-CoV-2 screening under poor conditions.


Assuntos
/métodos , RNA Viral/análise , /genética , Proteínas de Bactérias , Proteínas Associadas a CRISPR , Sistemas CRISPR-Cas , Linhagem Celular Tumoral , Colorimetria , DNA/química , Sondas de DNA , Endodesoxirribonucleases , Ouro/química , Humanos , Nanopartículas Metálicas/química
6.
Biomed Eng Online ; 20(1): 18, 2021 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-33563294

RESUMO

BACKGROUND: Advances in regenerative medicine technologies have been strongly proposed in the management of thyroid diseases. Mechanistically, the adoption of thyroid bioengineering requires a scaffold that shares a similar three-dimensional (3D) space structure, biomechanical properties, protein component, and cytokines to the native extracellular matrix (ECM). METHODS: 24 male New Zealand white rabbits were used in this experimental study. The rabbit thyroid glands were decellularized by immersion/agitation decellularization protocol. The 3D thyroid decellularization scaffolds were tested with histological and immunostaining analyses, scanning electron microscopy, DNA quantification, mechanical properties test, cytokine assay and cytotoxicity assays. Meanwhile, the decellularization scaffold were seeded with human thyroid follicular cells, cell proliferation and thyroid peroxidase were determined to explore the biocompatibility in vitro. RESULTS: Notably, through the imaging studies, it was distinctly evident that our protocol intervention minimized cellular materials and maintained the 3D spatial structure, biomechanical properties, ECM composition, and biologic cytokine. Consequently, the decellularization scaffold was seeded with human thyroid follicular cells, thus strongly revealing its potential in reinforcing cell adhesion, proliferation, and preserve important protein expression. CONCLUSIONS: The adoption of our protocol to generate a decellularized thyroid scaffold can potentially be utilized in transplantation to manage thyroid diseases through thyroid bioengineering.

7.
Proc Natl Acad Sci U S A ; 118(8)2021 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-33593918

RESUMO

Low complexity (LC) head domains 92 and 108 residues in length are, respectively, required for assembly of neurofilament light (NFL) and desmin intermediate filaments (IFs). As studied in isolation, these IF head domains interconvert between states of conformational disorder and labile, ß-strand-enriched polymers. Solid-state NMR (ss-NMR) spectroscopic studies of NFL and desmin head domain polymers reveal spectral patterns consistent with structural order. A combination of intein chemistry and segmental isotope labeling allowed preparation of fully assembled NFL and desmin IFs that could also be studied by ss-NMR. Assembled IFs revealed spectra overlapping with those observed for ß-strand-enriched polymers formed from the isolated NFL and desmin head domains. Phosphorylation and disease-causing mutations reciprocally alter NFL and desmin head domain self-association yet commonly impede IF assembly. These observations show how facultative structural assembly of LC domains via labile, ß-strand-enriched self-interactions may broadly influence cell morphology.

8.
Biotechnol Bioeng ; 118(5): 2053-2066, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33615437

RESUMO

Polymerase chain reaction (PCR), a central technology for molecular diagnostics, is highly sensitive but susceptible to the risk of false positives caused by aerosol contamination, especially when an end-point detection mode is applied. Here, we proposed a solution by designing a clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 eraser strategy for eliminating potential contamination amplification. The CRISPR/Cas9 engineered eraser is firstly adopted into artpcr reverse-transcription PCR (RT-PCR) system to achieve contamination-free RNA detection. Subsequently, we extended this CRISPR/Cas9 eraser to the PCR system. We engineered conventional PCR primers to enable the amplified products to contain an implanted NGG (protospacer adjacent motif, PAM) site, which is used as a code for specific CRISPR/Cas9 recognition. Pre-incubation of Cas9/sgRNA with PCR mix leads to a selective cleavage of contamination amplicons, thus only the template DNA is amplified. The developed CRISPR/Cas9 eraser, adopted by both RT-PCR and PCR systems, showed high-fidelity detection of SARS-CoV-2 and African swine fever virus with a convenient strip test.


Assuntos
Sistemas CRISPR-Cas , Reação em Cadeia da Polimerase/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Vírus da Febre Suína Africana/isolamento & purificação , Animais , Humanos , RNA Guia , RNA Viral/isolamento & purificação , Suínos
9.
ACS Nano ; 15(1): 1167-1178, 2021 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-33498106

RESUMO

Existing methods for RNA diagnostics, such as reverse transcription PCR (RT-PCR), mainly rely on nucleic acid amplification (NAA) and RT processes, which are known to introduce substantial issues, including amplification bias, cross-contamination, and sample loss. To address these problems, we introduce a confinement effect-inspired Cas13a assay for single-molecule RNA diagnostics, eliminating the need for NAA and RT. This assay involves confining the RNA-triggered Cas13a catalysis system in cell-like-sized reactors to enhance local concentrations of target and reporter simultaneously, via droplet microfluidics. It achieves >10 000-fold enhancement in sensitivity when compared to the bulk Cas13a assay and enables absolute digital single-molecule RNA quantitation. We experimentally demonstrate its broad applicability for precisely counting microRNAs, 16S rRNAs, and SARS-CoV-2 RNA from synthetic sequences to clinical samples with excellent accuracy. Notably, this direct RNA diagnostic technology enables detecting a wide range of RNA molecules at the single-molecule level. Moreover, its simplicity, universality, and excellent quantification capability might render it to be a dominant rival to RT-qPCR.


Assuntos
Sistemas CRISPR-Cas , Microfluídica , RNA/análise , Linhagem Celular Tumoral , Enterococcus faecalis , Escherichia coli , Humanos , Klebsiella pneumoniae , Células MCF-7 , MicroRNAs/análise , Pseudomonas aeruginosa , RNA Ribossômico 16S/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Staphylococcus aureus
10.
Biomed Res Int ; 2021: 6685723, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33506029

RESUMO

Purpose: To investigate whether the radiomics analysis of MR imaging in the hepatobiliary phase (HBP) can be used to predict microvascular invasion (MVI) in patients with hepatocellular carcinoma (HCC). Method: A total of 130 patients with HCC, including 80 MVI-positive patients and 50 MVI-negative patients, who underwent MR imaging with Gd-EOB-DTPA were enrolled. Least absolute shrinkage and selection operator (LASSO) regression was applied to select radiomics parameters derived from MR images obtained in the HBP 5 min, 10 min, and 15 min images. The selected features at each phase were adopted into support vector machine (SVM) classifiers to establish models. Multiple comparisons of the AUCs at each phase were performed by the Delong test. The decision curve analysis (DCA) was used to analyze the classification of MVI-positive and MVI-negative patients. Results: The most predictive features between MVI-positive and MVI-negative patients included 9, 8, and 14 radiomics parameters on HBP 5 min, 10 min, and 15 min images, respectively. A model incorporating the selected features produced an AUC of 0.685, 0.718, and 0.795 on HBP 5 min, 10 min, and 15 min images, respectively. The predictive model for HBP 5 min, 10 min and 15 min showed no significant difference by the Delong test. DCA indicated that the predictive model for HBP 15 min outperformed the models for HBP 5 min and 10 min. Conclusions: Radiomics parameters in the HBP can be used to predict MVI, with the HBP 15 min model having the best differential diagnosis ability.


Assuntos
Carcinoma Hepatocelular , Gadolínio DTPA/uso terapêutico , Neoplasias Hepáticas , Imagem por Ressonância Magnética/métodos , Neovascularização Patológica , Idoso , Carcinoma Hepatocelular/diagnóstico por imagem , Carcinoma Hepatocelular/patologia , Diagnóstico Diferencial , Feminino , Humanos , Fígado/diagnóstico por imagem , Fígado/patologia , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/patologia , Masculino , Microvasos/diagnóstico por imagem , Microvasos/patologia , Pessoa de Meia-Idade , Neovascularização Patológica/diagnóstico por imagem , Neovascularização Patológica/patologia , Interpretação de Imagem Radiográfica Assistida por Computador , Estudos Retrospectivos
11.
Acta Crystallogr D Struct Biol ; 77(Pt 1): 108-116, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33404530

RESUMO

Apical sodium-dependent bile acid transporter (ASBT) mediates the uptake of bile acids from the ileum lumen into enterocytes and presents a potential target for the treatment of several metabolic diseases, including type 2 diabetes. It has been proposed that the underlying mechanism for transport by ASBT is an elevator-style alternating-access model, which was deduced mainly by comparing high-resolution structures of two bacterial ASBT homologs (ASBTNM from Neisseria meningitides and ASBTYf from Yersinia frederiksenii) in different conformations. However, one important issue is that the only outward-facing structure (PDB entry 4n7x) was obtained with an Na+-binding site mutant of ASBTYf, which severely cripples its transport function, and therefore the physiological relevance of the conformation in PDB entry 4n7x requires further careful evaluation. Here, another crystal structure is reported of ASBTYf that was captured in a state closely resembling the conformation in PDB entry 4n7x using an engineered disulfide bridge. The introduced cysteine mutations avoided any proposed Na+- or substrate-binding residues, and the resulting mutant retained both structural and functional integrity and behaved similarly to wild-type ASBTYf. These data support the hypothesis that the PDB entry 4n7x-like structure represents a functional outward-facing conformation of ASBTYf in its transport cycle.

12.
Acta Crystallogr D Struct Biol ; 77(Pt 1): 117-125, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33404531

RESUMO

Apical sodium-dependent bile acid transporter (ASBT) retrieves bile acids from the small intestine and plays a pivotal role in enterohepatic circulation. Currently, high-resolution structures are available for two bacterial ASBT homologs (ASBTNM from Neisseria meningitides and ASBTYf from Yersinia frederiksenii), from which an elevator-style alternating-access mechanism has been proposed for substrate transport. A key concept in this model is that the substrate binds to the central cavity of the transporter so that the elevator-like motion can expose the bound substrate alternatingly to either side of the membrane during a transport cycle. However, no structure of an ASBT has been solved with a substrate bound in its central cavity, so how a substrate binds to ASBT remains to be defined. In this study, molecular docking, structure determination and functional analysis were combined to define and validate the details of substrate binding in ASBTYf. The findings provide coherent evidence to provide a clearer picture of how the substrate binds in the central cavity of ASBTYf that fits the alternating-access model.

13.
Cell Immunol ; 360: 104256, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33360167

RESUMO

The immune/inflammatory responses regulated by B cells are the critical determinants of atherosclerosis. B-cell receptor (BCR) plays pivotal roles in regulating B cell function. However, the composition and molecular characteristics of the BCR repertoire in atherosclerotic patients have not been fully elucidated. Herein we analyzed BCR repertoire in circulation and plaques of atherosclerotic patients by sequencing the BCR heavy chain complement determining region 3 (BCRH CDR3). Our data showed that in plaques, BCR repertoire was dramatically skewed and their combinations and diversity were significantly decreased, while the frequency of public and dominant B-cell clones was markedly increased. Additionally, BCRH CDR3 in plaques had higher positive selection pressure than that in the peripheral blood of normal subjects and atherosclerotic patients. Moreover, the BCRH CDR3 of some B cell clones specifically expanded in plaques were similar to that of antibodies which recognized certain pathogens including Influenza A virus, implying the possibility of the association between pathogens and atherosclerosis. The present study contributed to understand the roles of B cells in atherosclerosis. The design of specific antibodies based on the B cell clones specifically expanded in plaques might yield useful tools to reveal the pathogenesis of atherosclerosis, assess or alleviate the progression of atherosclerosis.

14.
Carbohydr Polym ; 251: 117117, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33142652

RESUMO

The development of biopolymer films is crucial for the replacement of conventional plastics. Tremendous effort is made to improve their performances by introducing biopolymers through the film manufacturing process. Herein, a sandwich-architectured film was proposed to efficiently improve the adhesion between the PS and PLA layers by using octenyl succinic anhydride-modified pea starch (OMPS) layer as the interlayer, leading to a highly mechanically enhanced interpenetrating network. Accordingly, the properties of the films were enhanced due to the synergism effect of sandwich architecture. In particular, the WVP value of the sandwich-architectured films (0.25 ∼ 0.89×10-10g·m-1·s-1·Pa-1) decreased more than 7-fold compared with the OMPS20 film, and the OP value of the sandwich-architectured films (0.256 ∼ 1.229×10-12cm3·m·m-2·s-1·Pa-1) decreased more than 10-fold in comparison to the PLA film. Benefitting from the characteristics investigated above, the films exhibited a favorable effect on strawberry storage. Overall, the fabricated eco-friendly sandwich-architectured films have shown great potential for biodegradable packaging applications.


Assuntos
Conservação de Alimentos/métodos , Fragaria/química , Ervilhas/química , Poliésteres/química , Amido/química , Embalagem de Alimentos/métodos , Frutas/química , Amido/análogos & derivados , Resistência à Tração
15.
Biosens Bioelectron ; 172: 112749, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33160233

RESUMO

Telomeric repeat amplification protocol (TRAP) has been the most widely used method for assessing the telomerase activity from cells and tissues. However, cell lysates, body fluid samples, or tumor tissue samples often contain high concentrations of protein or other complex matrices, which are usually inhibiting the TRAP response, thus leading to false-negative results. Internal control (IC) involved TRAP enables reliable telomerase activity assay but requires time consuming and laborious electrophoretic separation to visualize telomeric repeat DNA and internal control products from TRAP reaction, severely limiting its application in clinical diagnosis. Herein, a colorimetric code system based on programmable CRISPR-Cas12a technology and gold nano-particles (AuNPs) probe has been developed to analyse telomeric repeat DNA and internal control in TRAP products, enabling the rapid detection of telomerase activity and identification of false-negatives with naked-eye. We transform the detection results into three typical colorimetric codes-positive (P), negative (N) and false-negative (FN), making the judgement of detection results more convenient and user-friendly. The platform has also been applied in accurate detection of clinical liver cancer specimens for telomerase activity with a detection sensitivity of 93.75% and a specificity of 93.75% based on Youden index analysis. As a proof of concept, we further demonstrated the feasibility of Cas9-mediated triple-line lateral flow assay (TL-LFA), which enabled the detection of telomeric repeat DNA and internal control on a single triple-line test strip, achieving convenient and accurate telomerase activity assay.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Telomerase , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Colorimetria , Ouro , Sensibilidade e Especificidade , Telomerase/genética , Telomerase/metabolismo
16.
Artigo em Inglês | MEDLINE | ID: mdl-33295064

RESUMO

Accurate and large-scale screening of infected individuals has proven to be an effective means to control the spread of COVID-19. Currently, many assays have been developed to meet the huge testing requirements and the availability of diverse detection settings. However, few methods emphasize the capability to simultaneously detect two genes in a single test, which is a key measure to improve detection accuracy, as adopted by the gold standard RT-qPCR method. Herein, we developed a CRISPR/Cas9-mediated triple-line lateral flow assay (TL-LFA) combined with multiplex reverse transcription-recombinase polymerase amplification (RT-RPA) for rapid and simultaneous dual-gene detection of SARS-CoV-2 in a single strip test. This assay is characterized by the detection of envelope (E) and open reading frame 1ab (ORF1ab) genes from cell-cultured SARS-CoV-2 and SARS-CoV-2 viral RNA standards, showing a sensitivity of 100 RNA copies per reaction (25 µL). Furthermore, dual-gene analysis of 64 nasopharyngeal swab clinical samples showed 100% negative predictive agreement (NPA) and 97.14% positive predictive agreement (PPA). Expectantly, this developed platform will provide a more accurate and convenient pathway for diagnosis of COVID-19 or other infectious diseases in low-resource regions.

17.
J BUON ; 25(5): 2287-2292, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33277847

RESUMO

PURPOSE: To investigate the changes in tumor markers (TMs), coagulation function and vascular endothelial growth factor (VEGF) in patients with ovarian cancer (OC) and benign ovarian disease (BOD). METHODS: A total of 68 OC patients admitted to and treated in our hospital were selected (OC group), and another 68 BOD patients in the same time period were enrolled (BOD group). The variations in TMs, coagulation function and VEGF in OC and BOD patients were explored by analyzing the TMs, coagulation function and expression levels of serum VEGF and D-dimer in OC group and BOD group as well as the differences in TMs and coagulation function in patients in different stages. RESULTS: The values of TMs such as cancer antigen 125 (CA125), carbohydrate antigen 19.9 (CA19.9) and human epididymis protein 4 (HE4) in OC group were remarkably higher than those in BOD group, with significant differences (p<0.05). The values of those TMs were relatively low in the patients in stage I-II but relatively high in the patients in stage III-IV, and the patients in stage I-II had evidently lower values of those TMs than those in stage III-IV (p<0.05). The coagulation function was similar in both groups (p>0.05), while OC group exhibited a notably higher serum fibrinogen (FIB) level than BOD group (p<0.05). The levels of coagulation function indexes [prothrombin time (PT), thrombin time (TT) and activated partial thromboplastin time (APTT)] in the patients in stage I-II were comparable to those in stage III-IV, showing no differences (p>0.05), but the serum FIB level was markedly higher in the patients in stage III-IV than that in in stage I-II (p<0.05). The expression level of serum VEGF was increased distinctly in OC group compared with that in BOD group [(378.15±94.45) pg/mL vs. (164.02±67.38) pg/mL, p<0.05]. Moreover, OC group manifested obviously elevated expression level of serum D-dimer in comparison with BOD group [(4.58±1.48) µg/mL vs. (0.67±0.12) µg/mL, p<0.05]. CONCLUSIONS: TMs, coagulation function indexes and serum VEGF and D-dimer are highly expressed in OC patients, and the combined detection of TMs, coagulation function and serum VEGF can serve as an important method of diagnosing OC.

18.
Artigo em Inglês | MEDLINE | ID: mdl-33229555

RESUMO

The neural mechanisms underlying the impacts of noise on nonauditory function, particularly learning and memory, remain largely unknown. Here, we demonstrate that rats exposed postnatally (between postnatal days 9 and 56) to structured noise delivered at a sound pressure level of ∼65 dB displayed significantly degraded hippocampus-related learning and memory abilities. Noise exposure also suppressed the induction of hippocampal long-term potentiation (LTP). In parallel, the total or phosphorylated levels of certain LTP-related key signaling molecules in the synapses of the hippocampus were down-regulated. However, no significant changes in stress-related processes were found for the noise-exposed rats. These results in a rodent model indicate that even moderate-level noise with little effect on stress status can substantially impair hippocampus-related learning and memory by altering the plasticity of synaptic transmission. They support the importance of more thoroughly defining the unappreciated hazards of moderately loud noise in modern human environments.

19.
Am J Transl Res ; 12(10): 6395-6408, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33194038

RESUMO

Massive neuron loss is the key reason for poor prognoses in patients with traumatic brain injury (TBI), and astrocytes function as nutrition-providing neurons. Therefore, researchers must determine the potential role of astrocytes in neural regeneration after TBI. Our previous studies established that upregulating CD24 in the hippocampus might improve cognitive functions after TBI. However, whether CD24 in hippocampal astrocytes is involved in neural regeneration after TBI remains unknown. Therefore, we detected the CD24 expression in the ipsilateral hippocampus via western blot and quantitative real-time PCR. We further investigated the CD24 expression patterns in hippocampal astrocytes via immunofluorescence staining. We then injected adeno-associated virus-Gfa2-siRNA-CD24 (AAV-CD24) into the astrocytes to downregulate CD24 and analyzed the related cellular signals. Golgi-Cox staining and the growth associated protein-43 (GAP43) level were used to observe neuronal morphology and neural regeneration around the astrocytes in the ipsilateral hippocampus, and the Morris water maze test was used to assess neural functional recovery. The CD24 protein and mRNA levels in the cornu ammonis and dentate gyrus regions of the ipsilateral hippocampus were elevated after TBI, and high CD24 expression was widespread in the hippocampal astrocytes after TBI. Specific inhibition of CD24 in the hippocampal astrocytes interfered with the activation of Src homology region 2 containing protein tyrosine phosphatase 2 (SHP2) and extracellular signal regulated kinase (ERK), shortened the neuronal dendritic spines, decreased the GAP43 level and impaired the cognitive functions of the TBI-model mice. These results revealed that elevated hippocampal CD24 in astrocytes participated in neural regeneration in mice after TBI, possibly by activating the SHP2/ERK pathway.

20.
J Physiol Biochem ; 2020 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-33201408

RESUMO

Dexamethasone augments mitochondrial protein abundance. The translocase of the outer membrane (Tom) of mitochondria plays a major role in importing largely cytosolically synthesized proteins into mitochondria. We hypothesize that dexamethasone upregulates the Tom transport system, leading to increase of mitochondrial protein localization. Tom20 and Tom70 are the two major subunits. Dexamethasone increased Tom20 and Tom70 mRNA levels by 53 ± 11% and 25 ± 9% and mitochondrial protein abundance by 27 ± 7% and 25 ± 4% (p < 0.05 for all), respectively, in HEK293 cells. In parallel, dexamethasone elevated the SGK1 mRNA by 79 ± 17% and activity by 190 ± 42%, and mitochondrial protein level by 41 ± 2% (all p < 0.05) without significantly affecting the cytosol counterpart. The discovery of the effect of dexamethasone on SGK1 protein restricted in the mitochondria attracted us to examine the effect of the hormone on MnSOD, an enzyme with known mitochondrial localization and function. Similarly, dexamethasone significantly increased MnSOD transcripts by 67 ± 15% and protein level only in the mitochondria dose-dependently. Inhibition of SGK1 by GSK650394 and RNAi significantly attenuated the effects of the hormone on Tom20, Tom70, and MnSOD, indicating that SGK1 relays the effects of dexamethasone. Catalase inhibited the effects of dexamethasone on SGK1 and the subsequent effects of SGK1 on Tom20, Tom70, and MnSOD. Finally, knock-down of Tom20 and Tom70 by their siRNAs reduced dexamethasone-induced increases in the mitochondrial localization of SGK1 and MnSOD proteins. In conclusion, dexamethasone upregulates Tom20, Tom70, and MnSOD, and these effects are dependent on reactive oxygen species and SGK1. Dexamethasone-induced increases of SGK1 and MnSOD mitochondrial localization requires Tom20 and Tom70.

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