Publications by authors named "Xiaojuan Ding"

21 Publications

  • Page 1 of 1

Fluorescence spectroscopy and molecular docking analysis of the binding of Lactobacillus acidophilus GIM1.208 β-glucosidase with quercetin glycosides.

Enzyme Microb Technol 2021 May 11;146:109761. Epub 2021 Feb 11.

School of Liquor & Food Engineering, Guizhou University, National Forestry and Grassland Bureau Prickly Pear Engineering Technology Research Center, Key Laboratory of Agricultural and Animal Products Store and Processing of Guizhou Province, Guiyang, 550025, China.

Lactobacillus acidophilus is an important probiotic. The β-glucosidase produced by L. acidophilus GIM1.208 can transform quercetin glycosides of Rosa roxburghii Tratt to release quercetin and improve the functional activity of raw materials. Understanding the interaction and the characteristics of the two will lay a theoretical foundation for the site-directed transformation and functional application of the catalytic active site of enzymes. In our study, using the heterologously expressed and highly stable, purified L. acidophilus GIM1.208 BGL as the strain, the representative quercetin in β-glucosidase and Rosa roxburghii Tratt was preliminarily predicted and explored using ultraviolet-visible absorption spectroscopy. Fluorescence spectroscopy combined with molecular docking was used to determine the interaction characteristics of the glycoside substrates, rutin (Rut) and isoquercitrin (Iso). Results from molecular docking showed that Asp159, Arg56, Iso294, Phe292, and Gly25 were the main residues of β-glucosidase and Rut. Arg56 was found to be the most crucial residue of β-glucosidase and isoquercitrin; the interaction between Rut and Iso and β-glucosidase was mainly driven by hydrogen bonding. The combined free energy of β-glucosidase and Iso was found to be -182.10 kcal/mol, while that of β-glucosidase and Rut was -32.37 kcal/mol. The results of fluorescence spectroscopy showed that the fluorescence intensity of β-glucosidase decreased with an increase in Rut and Iso concentrations. This interaction made β-glucosidase quench endogenous fluorescence, which was static quenching. The binding constants of Rut and Iso with β-glucosidase were determined to be 0.50×10 and 0.31×10 L/mol, respectively, indicating that rutin had a stronger affinity when interacting with β-glucosidase. These findings were consistent with our prediction results determined using molecular docking studies.
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http://dx.doi.org/10.1016/j.enzmictec.2021.109761DOI Listing
May 2021

miR-145-5p exerts anti-tumor effects in diffuse large B-cell lymphoma by regulating S1PR1/STAT3/AKT pathway.

Leuk Lymphoma 2021 08 13;62(8):1884-1891. Epub 2021 Mar 13.

Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.

To investigate the molecular mechanism of miR-145-5p in diffuse large B-cell lymphoma (DLBCL) tissues and cells. The tissues from patients with DLBCL were collected for RT-qPCR or immunohistochemistry. Cell viability, proliferation, migration, invasion, the relationship between miR-145-5p and S1PR1, and proteins related pathway were detected using CCK-8, BrdU staining, Transwell assay, dual luciferase report assay, and western blotting, respectively. The results showed that miR-145-5p was down-regulated and positively correlated with the survival of DLBCL patients. Overexpression of miR-145-5p inhibited cell proliferation, migration, and invasion in cell model. miR-145-5p directly targeted S1PR1. miR-145-5p down-regulated S1PR1, p-AKT/AKT, and p-STAT3 expression. The reduction of miR-145-5p-induced cell movement was reversed by S1PR1 overexpression. Moreover, S1PR1-induced addition of cell growth was clearly alleviated in LY294002 or S3I-201 treated cells. S1PR1 was up-regulated in the tissues of DLBCL patients. In conclusion, miR-145-5p regulated DLBCL cell growth and movement through suppressing S1PR1/STAT3/AKT pathway.
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http://dx.doi.org/10.1080/10428194.2021.1894642DOI Listing
August 2021

Breast cancer cells promote self-migration by secreting interleukin 8 to induce NET formation.

Gene 2020 Sep 13;754:144902. Epub 2020 Jun 13.

Department of Pathology, Anhui Medical University, Hefei 230032, PR China. Electronic address:

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http://dx.doi.org/10.1016/j.gene.2020.144902DOI Listing
September 2020

NHI-Triggered [4 + 2] Annulation of α,β-Unsaturated Ketoxime Acetates with -Acetyl Enamides for the Synthesis of Pyridines.

J Org Chem 2020 06 9;85(12):8157-8165. Epub 2020 Jun 9.

College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China.

The NHI-triggered formal [4 + 2] annulation of α,β-unsaturated ketoxime acetates with -acetyl enamides has been developed. The current protocol employs electron-rich enamides as C2 synthons and enables the efficient and straightforward construction of polysubstituted pyridines in moderate to good yields based on metal-free systems. The reaction tolerates a wide range of functional groups and represents an alternate route toward the synthesis of pyridine derivatives.
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http://dx.doi.org/10.1021/acs.joc.0c01081DOI Listing
June 2020

CD41-deficient exosomes from non-traumatic femoral head necrosis tissues impair osteogenic differentiation and migration of mesenchymal stem cells.

Cell Death Dis 2020 04 27;11(4):293. Epub 2020 Apr 27.

Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.

Non-traumatic osteonecrosis of the femoral head (ONFH) is clinically a devastating and progressive disease without an effective treatment. Mesenchymal stem cells (MSCs) transplantation has been used to treat ONFH in early stage, but the failure rate of this therapy is high due to the reduced osteogenic differentiation and migration of the transplanted MSCs related with pathological bone tissues. However, the mechanism responsible for this decrease is still unclear. Therefore, we assume that the implanted MSCs might be influenced by signals delivered from pathological bone tissue, where the exosomes might play a critical role in this delivery. This study showed that exosomes from ONFH bone tissues (ONFH-exos) were able to induce GC-induced ONFH-like damage, in vivo and impair osteogenic differentiation and migration of MSCs, in vitro. Then, we analyzed the differentially expressed proteins (DEPs) in ONFH-exos using proteomic technology and identified 842 differentially expressed proteins (DEPs). On the basis of gene ontology (GO) enrichment analysis of DEPs, fold-changes and previous report, cell adhesion-related CD41 (integrin α2b) was selected for further investigation. Our study showed that the CD41 (integrin α2b) was distinctly decreased in ONFH-exos, compared to NOR-exos, and downregulation of CD41 could impair osteogenic differentiation and migration of the MSCs, where CD41-integrin β3-FAK-Akt-Runx2 pathway was involved. Finally, our study further suggested that CD41-affluent NOR-exos could restore the glucocorticoid-induced decline of osteogenic differentiation and migration in MSCs, and prevent GC-induced ONFH-like damage in rat models. Taken together, our study results revealed that in the progress of ONFH, exosomes from the pathological bone brought about the failure of MSCs repairing the necrotic bone for lack of some critical proteins, like integrin CD41, and prompted the progression of experimentally induced ONFH-like status in the rat. CD41 could be considered as the target of early diagnosis and therapy in ONFH.
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http://dx.doi.org/10.1038/s41419-020-2496-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7184624PMC
April 2020

Production and characterization of monoclonal antibodies against ROP18 with strain-specific reactivity.

Parasitology 2020 08 12;147(9):940-948. Epub 2020 Feb 12.

Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Provincial Laboratory of Zoonoses of High Institutions, School of Basic Medical Sciences, Anhui Medical University, Hefei, China.

The rhoptry kinase 18 of Toxoplasma gondii (TgROP18) has been identified as a key virulence factor that allows the parasite to escape from host immune defences and promotes its proliferation in host cells. Although much research is focused on the interaction between host cells and TgROP18, the development of monoclonal antibodies (mAbs) against TgROP18 has not been reported till date. To produce mAbs targeting TgROP18, two hybridomas secreting mAbs against TgROP18, designated as A1 and T2, were generated using cell fusion technology. The subtypes of the A1 and T2 mAbs were identified as IgG3 λ and IgM κ, and peptide scanning revealed that the core sequences of the antigenic epitopes were 180LRAQRRRSELVFE192 and 351NYFLLMMRAEADM363, respectively. The T2 mAb specifically reacted with both T. gondii type I and Chinese I, but not with T. gondii type II, Plasmodium falciparum or Schistosoma japonicum. Finally, the sequences of heavy chain and light chain complementarity-determining regions of T2 were amplified, cloned and characterized, making the modification of the mAb feasible in the future. The development of mAbs against TgROP18 would aid the investigation of the molecular mechanisms underlying the modulation of host cellular functions by TgROP18, and in the development of strategies to diagnose and treat Toxoplasmosis.
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http://dx.doi.org/10.1017/S0031182020000177DOI Listing
August 2020

Copper-Catalyzed N-O Cleavage of α,β-Unsaturated Ketoxime Acetates toward Structurally Diverse Pyridines.

J Org Chem 2020 02 21;85(4):2532-2542. Epub 2020 Jan 21.

College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering , Nanjing Tech University , Nanjing 211816 , China.

The copper-catalyzed [4 + 2] annulation of α,β-unsaturated ketoxime acetates with 1,3-dicarbonyl compounds for the synthesis of three classes of structurally diverse pyridines has been developed. This method employs 1,3-dicarbonyl compounds as C2 synthons and enables the synthesis of multifunctionalized pyridines with diverse electron-withdrawing groups in moderate to good yields. The mechanistic investigation suggests that the reactions proceed through an ionic pathway.
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http://dx.doi.org/10.1021/acs.joc.9b03238DOI Listing
February 2020

Target-driven rolling walker based electrochemical biosensor for ultrasensitive detection of circulating tumor DNA using [email protected] tags.

Biosens Bioelectron 2020 Jan 2;148:111826. Epub 2019 Nov 2.

Department of Laboratory Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China. Electronic address:

In this study, a multiple-legged and highly integrated DNA rolling walker based electrochemical biosensor was developed for ultrasensitive ctDNA analysis through rolling circle amplification (RCA) with [email protected] ([email protected]) as electrochemical indicator. Upon target-driven RCA, the multiple-legged walker could move along with the predesigned track by strand displacement reactions, resulting in numbers of legs binding irreversibly to iStep probes. The binding of massive legs to iStep probes could effectively impede [email protected] tags binding on the surface of sensor and then reached a "signal off" state. Benefiting from the highly amplified efficiency of rolling walker machine and [email protected] tags, the established biosensor performed high sensitivity for target detection with a low limit of detection down to 0.29 fM. Moreover, the target ctDNA could hybridize with the ring and capture probe simultaneously, greatly enhancing the specificity of the developed biosensing method. Thus, this biosensing method is a promising tool for detection of ctDNA in the field of clinical diagnostic and tumor progression assessment.
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http://dx.doi.org/10.1016/j.bios.2019.111826DOI Listing
January 2020

CircACC1 Regulates Assembly and Activation of AMPK Complex under Metabolic Stress.

Cell Metab 2019 07 30;30(1):157-173.e7. Epub 2019 May 30.

The Chinese Academy of Sciences (CAS), Key Laboratory of Innate Immunity & Chronic Disease, CAS Center for Excellence in Cell & Molecular Biology, School of Life Sciences, University of Science & Technology of China, Hefei 230026, China; Translational Research Institute, Henan Provincial People's Hospital, Academy of Medical Science, Zhengzhou University, Zhengzhou 450003, China; Key Laboratory of Stem Cell Differentiation & Modification, School of Clinical Medicine, Henan University, Zhengzhou 450003, China. Electronic address:

We report that circACC1, a circular RNA derived from human ACC1, plays a critical role in cellular responses to metabolic stress. CircACC1 is preferentially produced over ACC1 in response to serum deprivation by the transcription factor c-Jun. It functions to stabilize and promote the enzymatic activity of the AMPK holoenzyme by forming a ternary complex with the regulatory β and γ subunits. The cellular levels of circACC1 modulate both fatty acid β-oxidation and glycolysis, resulting in profound changes in cellular lipid storage. In a tumor xenograft model, silencing or enforced expression of circACC1 resulted in growth inhibition and enhancement, respectively. Moreover, increased AMPK activation in colorectal cancer tissues was frequently associated with elevated circACC1 expression. We conclude that circACC1 serves as an economic means to elicit AMPK activation and moreover propose that cancer cells exploit circACC1 during metabolic reprogramming.
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http://dx.doi.org/10.1016/j.cmet.2019.05.009DOI Listing
July 2019

ARPC2 promotes breast cancer proliferation and metastasis.

Oncol Rep 2019 Jun 12;41(6):3189-3200. Epub 2019 Apr 12.

Department of Pathology, Anhui Medical University, Hefei, Anhui 230032, P.R. China.

Actin-related protein 2/3 complex (ARPC2) is an actin‑binding component involved in the regulation of actin polymerization. It mediates the formation of branched actin networks and contacts the mother actin filament. Migration and invasion are key processes which enable tumor cells to infiltrate blood vessels or lymphatic vessels, and the actin pathway plays a very important role. Given that ARPC2 is critical to this progression, the present study focused on ARPC2 activity in breast cancer (BrCa) cell invasion and migration. Limited data are available on the expression and role of ARPC2 proteins in breast carcinomas. We screened the Oncomine database for messenger RNAs (mRNAs) that are upregulated in BrCa and found that ARPC2 was one of the most consistently involved mRNAs in BrCa. The analysis of immunohistochemical data revealed that ARPC2 expression was higher in breast cancerous tissues than in adjacent non‑cancerous tissues. In addition, ARPC2 was highly associated with the tumor stage, nodal metastasis, and overall survival of patients with BrCa. We performed siRNA‑ARPC2 transfection to investigate the effect of ARPC2 on the proliferation, migration, invasion and arrest of BrCa cells. It was revealed that ectopic ARPC2 expression significantly upregulated N‑cadherin, vimentin, ZEB1, MMP‑9 and MMP‑3 expression and also activated the TGF‑β pathway to contribute to epithelial‑mesenchymal transition (EMT). These results collectively indicated that ARPC2 promoted the tumorigenesis of breast carcinoma and the initiation of EMT. Therefore, ARPC2 was revealed to be a potential therapeutic target in patients with BrCa.
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http://dx.doi.org/10.3892/or.2019.7113DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6488984PMC
June 2019

NFATC2 is a novel therapeutic target for colorectal cancer stem cells.

Onco Targets Ther 2018 15;11:6911-6924. Epub 2018 Oct 15.

Key Laboratory of Laboratory Medical Diagnostics (Ministry of Education of China), Department of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, People's Republic of China,

Background: Colorectal cancer stem cells (CRC-SCs) contribute to the initiation and progression of colorectal cancer (CRC). However, the underlying mechanisms for the propagation of CRC-SCs have remained elusive.

Purpose: The objective of this study was to study the role of NFATC2 in maintenance of the stemness in CRC-SCs.

Method: The expression levels of mRNA and protein were determined by qRT-PCR and western-blot, respectively. CRC-SCs were isolated by spheroid formation assay and flowcytometry. The sphere-forming and self-renewal abilities of CRC-SCs were determined by spheroid formation assay. The tumorigenicity of CRC-SCs was determined by cell-derived xenograft model. Gene manipulation was performed by lentivirus-mediated delivery system.

Results: We first found that NFATC2 is upregulated in primary CRC-SCs. Overexpression of NFATC2 promotes self-renewal and the expression of stem cell markers of CRC-SCs. Conversely, knockdown of NFATC2 attenuates stem cell-like properties of CRC-SCs. Mechanistic analysis indicated that NFATC2 upregulates the expression of AJUBA, downregulates the phosphorylation level of YAP, and therefore activates the transcriptional activities of YAP and promotes the stemness of CRC-SCs.

Conclusion: Our findings demonstrate NFATC2 as an oncogene that can promote the stemness of CRC-SCs. This work suggests a novel therapeutic strategy against CRC caused by aberrant expression of NFATC2.
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http://dx.doi.org/10.2147/OTT.S169129DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6199214PMC
October 2018

BfvR, an AraC-Family Regulator, Controls Biofilm Formation and pH6 Antigen Production in Opposite Ways in Biovar Microtus.

Front Cell Infect Microbiol 2018 2;8:347. Epub 2018 Oct 2.

State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.

Biofilm formation is critical for blocking flea foregut and hence for transmission of by flea biting. In this study, we identified the regulatory role of the AraC-family transcriptional regulator BfvR (YPO1737 in strain CO92) in biofilm formation and virulence of biovar Microtus. Crystal violet staining, biofilm assay, colony morphology assay, intracellular c-di-GMP concentration determination, and BALB/c mice challenge were employed to reveal that BfvR enhanced biofilm formation while repressed its virulence in mice. Further molecular biological assays demonstrated that BfvR directly stimulated the expression of , and , which, in turn, affected the production of exopolysaccharide, LPS, and c-di-GMP, respectively. In addition, BfvR directly and indirectly repressed and transcription, respectively. We concluded that the modulation of biofilm- and virulence-related genes by BfvR led to increased biofilm formation and reduced virulence of biovar Microtus.
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http://dx.doi.org/10.3389/fcimb.2018.00347DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6176095PMC
September 2019

Engineering high-performance hairpin stacking circuits for logic gate operation and highly sensitive biosensing assay of microRNA.

Analyst 2017 Dec;142(24):4834-4842

The Affiliated Hospital of Binzhou Medical University, Shandong 256603, China.

Recently, hairpin stacking circuits (HSC) based on toehold-mediated strand displacement have been engineered to detect nucleic acids and proteins. However, the three metastable hairpins in a HSC system can potentially react non-specifically in the absence of a catalyst, limiting its practical application. Here, we developed a unique hairpin design guideline to eliminate circuit leakage of HSC, and the high-performance HSC was successfully implemented on logic gate building and biosensing. We began by analyzing the sources of circuit leakage and optimizing the toehold lengths of hairpins in the HSC system based on the surface plasmon resonance (SPR) technique. Next, a novel strategy of substituting two nucleotides in a specific domain, termed 'loop-domain substitution', was introduced to eliminate leakages. We also systematically altered the positions and numbers of the introduced substitutions to probe their potential contribution to circuit leakage suppression. Through these efforts, the circuit leakage of HSC was significantly reduced. Finally, by designing different DNA input strands, the logic gates could be activated to achieve the output signal. Using miRNA as a model analyte, this strategy could detect miRNA down to pM levels with minimized circuit leakage. We believe these work indicate significant progress in the DNA circuitry.
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http://dx.doi.org/10.1039/c7an01624gDOI Listing
December 2017

A simple surface plasmon resonance biosensor for detection of PML/RARα based on heterogeneous fusion gene-triggered nonlinear hybridization chain reaction.

Sci Rep 2017 10 25;7(1):14037. Epub 2017 Oct 25.

Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China.

In this work, a simple and enzyme-free surface plasmon resonance (SPR) biosensing strategy has been developed for highly sensitive detection of two major PML/RARα (promyelocytic leukemia, retinoic acid receptor alpha) subtypes based on the heterogeneous fusion gene-triggered nonlinear hybridization chain reaction (HCR). On the gold chip surface, the cascade self-assembly process is triggered after the introduction of PML/RARα. The different fragments of PML/RARα can specifically hybridize with capture probes (Cp) immobilized on the chip and the hybridization DNA (H). Then, the nonlinear HCR is initiated by the complex of Cp-PML/RARα-H with the introduction of two hybridization DNA chains (H and H). As a result, a dendritic nanostructure is achieved on the surface of chip, leading to a significant SPR amplification signal owing to its high molecular weight. The developed method shows good specificity and high sensitivity with detection limit of 0.72 pM for "L" subtype and 0.65 pM for "S" subtype. Moreover, this method has been successfully applied for efficient identification of clinical positive and negative PCR samples of the PML/RARα subtype. Thus, this developed biosensing strategy presents a potential platform for analysis of fusion gene and early diagnosis of clinical disease.
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http://dx.doi.org/10.1038/s41598-017-14361-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5656617PMC
October 2017

An enzyme-free surface plasmon resonance biosensing strategy for detection of DNA and small molecule based on nonlinear hybridization chain reaction.

Biosens Bioelectron 2017 Jan 24;87:345-351. Epub 2016 Aug 24.

Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China. Electronic address:

A label-free and enzyme-free surface plasmon resonance (SPR) biosensing strategy has been developed for highly sensitive and specific detection of target DNA by employing the nonlinear hybridization chain reaction (HCR) amplification. Nonlinear HCR is a hairpin-free system in which double-stranded DNA monomers could dendritically assemble into highly branched nanostructure upon introducing a trigger sequence. The target DNA partly hybridizes with capture probe on the gold sensing chip and the unpaired fragment of target DNA works as a trigger to initiate the nonlinear HCR, forming a chain-branching growth of DNA dendrimer by self-assembly. Real-time amplified SPR response is observed upon the introduction of nonlinear HCR system. The method is capable of detecting target DNA at the concentration down to 0.85 pM in 60min with a dynamic range from 1 pM to 1000 pM, and could discriminate target DNA from mismatched sequences. This biosensing strategy exhibits good reproducibility and precision, and has been successfully applied for detection of target DNA in complex sample matrices. In addition, the nonlinear HCR based SPR biosensing methodology is extended to the detection of adenosine triphosphate (ATP) by aptamer recognition. Thus, the versatile method might become a potential alternative tool for biomolecule detection in medical research and early clinical diagnosis.
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http://dx.doi.org/10.1016/j.bios.2016.08.077DOI Listing
January 2017

Toxoplasma gondii inhibits differentiation of C17.2 neural stem cells through Wnt/β-catenin signaling pathway.

Biochem Biophys Res Commun 2016 Apr 21;473(1):187-193. Epub 2016 Mar 21.

Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei 230032, PR China. Electronic address:

Toxoplasma gondii is a major cause of congenital brain disease. T. gondii infection in the developing fetus frequently results in major neural developmental damage; however, the effects of the parasite infection on the neural stem cells, the key players in fetal brain development, still remain elusive. This study is aiming to explore the role of T. gondii infection on differentiation of neural stem cells (NSCs) and elucidate the underlying molecular mechanisms that regulate the inhibited differentiation of NSCs induced by the infection. Using a differentiation medium, i.e. , DMEM: F12 (1:1 mixture) supplemented with 2% N2, C17.2 neural stem cells (NSCs) were able to differentiate to neurons and astrocytes, respectively evidenced by immunofluorescence staining of differentiation markers including βIII-tubulin and glial fibrillary acidic protein (GFAP). After 5-day culture in the differentiation medium, the excreted-secreted antigens of T. gondii (Tg-ESAs) significantly down-regulated the protein levels of βIII-tubulin and GFAP in C17.2 NSCs in a dose-dependent manner. The protein level of β-catenin in the nucleus of C17.2 cells treated with both wnt3a (a key activator for Wnt/β-catenin signaling pathway) and Tg-ESAs was significantly lower than that in the cells treated with only wnt3a, but significantly higher than that in the cells treated with only Tg-ESAs. In conclusion, the ESAs of T. gondii RH blocked the differentiation of C17.2 NCSs and downregulated the expression of β-catenin, an essential component of Wnt/β-catenin signaling pathway. The findings suggest a new mechanism underlying the neuropathogenesis induced by T. gondii infection, i.e. inhibition of the differentiation of NSCs via blockade of Wnt/β-catenin signaling pathway, such as downregulation of β-catenin expression by the parasite ESAs.
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http://dx.doi.org/10.1016/j.bbrc.2016.03.076DOI Listing
April 2016

A novel surface plasmon resonance biosensor for enzyme-free and highly sensitive detection of microRNA based on multi component nucleic acid enzyme (MNAzyme)-mediated catalyzed hairpin assembly.

Biosens Bioelectron 2016 Jun 18;80:98-104. Epub 2016 Jan 18.

Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China. Electronic address:

MicroRNAs (miRNAs) are potentially useful biomarkers for early diagnosis of human diseases. Here, a simple surface plasmon resonance (SPR) biosensor has been developed for highly sensitive detection of miRNA by designing a new enzyme-free and isothermal amplification strategy, named multi component nucleic acid enzyme-mediated mismatched catalyzed hairpin assembly (MNAzyme-CHA). The partial MNAzymes co-recognized the target to form a stable active MNAzyme, which continued to digest multiple hairpin H0 substrates, concomitantly generating a lot of fragments. The H0 fragments could initiate the mismatched CHA cycles, resulting in the generation of massive hairpin H1-H2 complexes. As a result, the H1-H2 complexes and streptavidin were attached to the sensor surface, leading to a significantly amplified SPR signal readout. The established biosensor showed high sensitivity and selectivity with a wide dynamic range from 1 pM to 100 nM. It was also successfully applied to the determination of target miRNA spiked into human total RNA samples. Thus, this developed biosensing strategy presents a simple and stable platform toward sensitive and convenient miRNA detection, and has great potential in assays of many other nucleic acids analytes for biomedical research and early clinical diagnosis.
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http://dx.doi.org/10.1016/j.bios.2016.01.048DOI Listing
June 2016

Surface plasmon resonance biosensor for highly sensitive detection of microRNA based on DNA super-sandwich assemblies and streptavidin signal amplification.

Anal Chim Acta 2015 May 2;874:59-65. Epub 2015 Apr 2.

Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China. Electronic address:

MicroRNAs (miRNAs) play an important regulatory role in cells and dysregulation of miRNA has been associated with a variety of diseases, making them a promising biomarker. In this work, a novel biosensing strategy has been developed for label-free detection of miRNA using surface plasmon resonance (SPR) coupled with DNA super-sandwich assemblies and biotin-strepavidin based amplification. The target miRNA is selectively captured by surface-bound DNA probes. After hybridization, streptavidin is employed for signal amplification via binding with biotin on the long DNA super-sandwich assemblies, resulting in a large increase of the SPR signal. The method shows very high sensitivity, capable of detecting miRNA at the concentration down to 9 pM with a wide dynamic range of 6 orders of magnitude (from 1 × 10(-11) M to 1 × 10(-6) M) in 30 min, and excellent specificity with discriminating a single base mismatched miRNA sequence. This biosensor exhibits good reproducibility and precision, and has been successfully applied to the detection of miRNA in total RNA samples extracted from human breast adenocarcinoma MCF-7 cells. It, therefore, offers a highly effective alternative approach for miRNA detection in biomedical research and clinical diagnosis.
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http://dx.doi.org/10.1016/j.aca.2015.03.021DOI Listing
May 2015

Toxoplasma gondii prevalent in China induce weaker apoptosis of neural stem cells C17.2 via endoplasmic reticulum stress (ERS) signaling pathways.

Parasit Vectors 2015 Feb 4;8:73. Epub 2015 Feb 4.

Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, 230032, PR China.

Background: Toxoplasma gondii, an obligate intracellular pathogen, has a strong affinity for the nervous system. TgCtwh3, a representative Chinese 1 Toxoplasma strain prevalent in China, has the polymorphic features of the effectors ROP16I/III with type I and GRA15II with type II Toxoplasma strains. The interaction of this atypical strain with host cells remains extremely elusive.

Methods: Using a transwell system, neural stem cells C17.2 were co-cultured with the tachyzoites of TgCtwh3 or standard type I RH strain. The apoptosis levels of C17.2 cells and the expression levels of related proteins in the endoplasmic reticulum stress (ERS)-mediated pathway were detected by flow cytometry and Western blotting.

Results: The apoptosis level of C17.2 cells co-cultured with TgCtwh3 had a significant increase compared to the negative control group; however, the apoptosis level in the TgCtwh3 group was significantly lower than that in the RH co-culture group. Western blotting analyses reveal that, after the C17.2 cells were co-cultured with TgCtwh3 and RH tachyzoites, the expression levels of caspase-12, CHOP and p-JNK in the cells increased significantly when compared to the control groups. After the pretreatment of Z-ATAD-FMK, an inhibitor of caspase-12, the apoptosis level of the C17.2 cells co-cultured with TgCtwh3 or RH tachyzoites had an apparent decline, and correspondingly, the expression levels of those related proteins were notably decreased.

Conclusions: Our findings suggest that TgCtwh3 may induce the apoptosis of the C17.2 cells by up-regulation of caspase-12, CHOP, and p-JNK, which are associated with ERS signaling pathways. This work contributes to better understanding the possible mechanism of brain pathology induced by T. gondii Chinese 1 isolates prevalent in China, and also reveals the potential value of ERS inhibitors to treat such related diseases in the future.
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http://dx.doi.org/10.1186/s13071-015-0670-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4322664PMC
February 2015

A simple electrochemical biosensor for highly sensitive and specific detection of microRNA based on mismatched catalytic hairpin assembly.

Biosens Bioelectron 2015 Jun 12;68:343-349. Epub 2015 Jan 12.

Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China. Electronic address:

MicroRNAs (miRNAs) play vital regulatory roles in cancer development and a variety of diseases, which make them become promising biomarkers. Here, a simple electrochemical biosensor was developed for highly sensitive and specific detection of target miRNA using mismatched catalytic hairpin assembly (CHA). The target miRNA triggered the toehold strand displacement assembly of two hairpin substrates, which led to the cyclic reuse of the target miRNA and the CHA products. Compared with the traditional CHA, mismatched CHA could decrease the nonspecific CHA products, which reduced the background signal significantly. Under the optimal experimental conditions and using differential pulse voltammetry, the established biosensor could detect target miRNA down to 0.6 pM (S/N=3) with a linear range from 1 pM to 25 nM, and discriminate target miRNA from mismatched miRNA with a high selectivity. It was also applied to the determination of miRNA spiked into human total RNA samples. Thus, this biosensing strategy might become a potential alternative tool for detection of miRNA in biomedical research and early clinical diagnosis.
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http://dx.doi.org/10.1016/j.bios.2015.01.026DOI Listing
June 2015

Toxoplasma gondii induce apoptosis of neural stem cells via endoplasmic reticulum stress pathway.

Parasitology 2014 Jun 10;141(7):988-95. Epub 2014 Mar 10.

Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei 230032, PR China.

Toxoplasma gondii is a major cause of congenital brain disease; however, the underlying mechanism of neuropathogenesis in brain toxoplasmosis remains elusive. To explore the role of T. gondii in the development of neural stem cells (NSCs), NSCs were isolated from GD14 embryos of ICR mice and were co-cultured with tachyzoites of T. gondii RH strain. We found that apoptosis levels of the NSCs co-cultured with 1×106 RH tachyzoites for 24 and 48 h significantly increased in a dose-dependent manner, as compared with the control. Western blotting analysis displayed that the protein level of C/EBP homologous protein (CHOP) was up-regulated, and caspase-12 and c-Jun N-terminal kinase (JNK) were activated in the NSCs co-cultured with the parasites. Pretreatment with endoplasmic reticulum stress (ERS) inhibitor (TUDCA) and caspase-12 inhibitor (Z-ATAD-FMK) inhibited the expression or activation of the key molecules involved in the ERS-mediated apoptotic pathway, and subsequently decreased the apoptosis levels of the NSCs induced by the T. gondii. The findings here highlight that T. gondii induced apoptosis of the NSCs through the ERS signal pathway via activation of CHOP, caspase-12 and JNK, which may constitute a potential molecular mechanism responsible for the cognitive disturbance in neurological disorders of T. gondii.
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http://dx.doi.org/10.1017/S0031182014000183DOI Listing
June 2014
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