Publications by authors named "Mengnan Guo"

8 Publications

  • Page 1 of 1

Roles of Motor Cortex Neuron Classes in Reach-Related Modulation for Hemiparkinsonian Rats.

Front Neurosci 2021 27;15:645849. Epub 2021 Apr 27.

Key Laboratory of Animal Resistance Biology of Shandong Province, College of Life Science, Shandong Normal University, Jinan, China.

Disruption of the function of the primary motor cortex (M1) is thought to play a critical role in motor dysfunction in Parkinson's disease (PD). Detailed information regarding the specific aspects of M1 circuits that become abnormal is lacking. We recorded single units and local field potentials (LFPs) of M1 neurons in unilateral 6-hydroxydopamine (6-OHDA) lesion rats and control rats to assess the impact of dopamine (DA) cell loss during rest and a forelimb reaching task. Our results indicated that M1 neurons can be classified into two groups (putative pyramidal neurons and putative interneurons) and that 6-OHDA could modify the activity of different M1 subpopulations to a large extent. Reduced activation of putative pyramidal neurons during inattentive rest and reaching was observed. In addition, 6-OHDA intoxication was associated with an increase in certain LFP frequencies, especially those in the beta range (broadly defined here as any frequency between 12 and 35 Hz), which become pathologically exaggerated throughout cortico-basal ganglia circuits after dopamine depletion. Furthermore, assessment of different spike-LFP coupling parameters revealed that the putative pyramidal neurons were particularly prone to being phase-locked to ongoing cortical oscillations at 12-35 Hz during reaching. Conversely, putative interneurons were neither hypoactive nor synchronized to ongoing cortical oscillations. These data collectively demonstrate a neuron type-selective alteration in the M1 in hemiparkinsonian rats. These alterations hamper the ability of the M1 to contribute to motor conduction and are likely some of the main contributors to motor impairments in PD.
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http://dx.doi.org/10.3389/fnins.2021.645849DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8111217PMC
April 2021

The protective role of protocatechuic acid against chemically induced liver fibrosis and .

Pharmazie 2021 May;76(5):232-238

Department of Pharmacology, Liaoning University of Traditional Chinese Medicine, Liaoning University, Shenyang, China; Research Center for Computer Simulating and Information Processing of Bio-macromolecules of Liaoning Province, Liaoning University, Shenyang, China; ; Email:

Liver fibrosis is the result of long-term liver injury and has a high incidence worldwide. Protocatechuic acid (PCA) is ubiquitous in vegetables, nuts, brown rice and herbal medicines, which is reported to possess anti-asthmatic, anti-cancer, and anti-oxidation properties. Our research aimed to investigate the effect of PCA on liver fibrosis. , TNF-α-induced hepatic stellate cell (HSC) model was used to assess the anti-fibrosis effects of PCA. , mice were treated with thioacetamide (TAA) to develop liver fibrosis. Body weight, organ index, histological changes, and proteins alteration of factors associated with TGF-β signaling pathway were used to assess the anti-fibrosis effects of PCA. Our results showed that PCA not only inhibited cell viability in TNF-α activated HSC-T6 cells , but also efficiently mitigated TAA-induced liver damage and fibrosis . Further experiments indicated that PCA played a protective role in liver fibrosis through regulation of the TGF-β signaling pathway downregulating the protein expression of p-Smad2, p-ERK, c-Jun. In summary, our findings provide a pharmacological justification for the clinical application of PCA in preventing or treating liver fibrosis.
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http://dx.doi.org/10.1691/ph.2021.0909DOI Listing
May 2021

Effects of intrastriatal injection of the dopamine receptor agonist SKF38393 and quinpirole on locomotor behavior in hemiparkinsonism rats.

Behav Brain Res 2021 May 1;411:113339. Epub 2021 May 1.

Key Laboratory of Animal Resistance Biology of Shandong Province, College of Life Science, Shandong Normal University, Jinan, People's Republic of China. Electronic address:

Dopamine (DA) in the striatum is essential to influence motor behavior and may lead to movement impairment in Parkinson's disease (PD). The present study examined the different functions of the DA D1 receptor (D1R) and DA D2 receptor (D2R) by intrastriatal injection of the D1R agonist SKF38393 and the D2R agonist quinpirole in 6-hydroxydopamine (6-OHDA)-lesioned and control rats. All rats separately underwent dose-response behavior testing for SKF38393 (0, 0.5, 1.0, and 1.5 μg/site) or quinpirole (0, 1.0, 2.0, and 3.0 μg/site) to determine the effects of the optimal modulating threshold dose. Two behavior assessment indices, the time of latency to fall and the number of steps on a rotating treadmill, were used as reliable readouts of motor stimulation variables for quantifying the motor effects of the drugs. The findings indicate that at threshold doses, SKF38393 (1.0 μg/site) and quinpirole (1.0 μg/site) produce a dose-dependent increase in locomotor activity compared to vehicle injection. The ameliorated behavioral responses to either SKF38393 or quinpirole in lesioned rats were greater than those in unlesioned control rats. Moreover, the dose-dependent increase in locomotor capacity for quinpirole was greater than that for SKF38393 in lesioned rats. These results can clarify several key issues related to DA receptors directly and may provide a basis for exploring the potential of future selective dopamine therapies for PD in humans.
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http://dx.doi.org/10.1016/j.bbr.2021.113339DOI Listing
May 2021

[Construction, expression and identification of chimeric foot-and-mouth disease virus-like particles].

Sheng Wu Gong Cheng Xue Bao 2020 Jul;36(7):1305-1313

State Key Laboratory of Veterinary Etiological Biology, OIE/National Foot-and-Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, Gansu, China.

To improve the specific recognition and presentation of virus-like particle (VLPs), and to develop immune-targeted VLPs vaccine, the gene fragment encoding OVA₂₅₇₋₂₆₄ peptide was inserted into the VP3 gene of foot-and-mouth disease virus (FMDV) between the 171th and 172th amino acids (aa) or 173th and 174th aa by reverse PCR. The recombinant proteins were expressed by using Escherichia coli and assembled into chimeric VLP (VLP(OVA)) in vitro after purification. The VLP(OVA) was measured by dynamic light scattering and transmission electron microscopy. The recombinant protein and the assembled VLPs were evaluated by Western blotting, enzyme-linked immunosorbent assay and laser scanning confocal microscopy to confirm the insertion of OVA₂₅₇₋₂₆₄ peptide into VP3 and its location. The results show that insertion of OVA₂₅₇₋₂₆₄ into the 173th and 174th aa of FMDV VP3 did not affect the assembly of VLPs. The VLP(OVA) in size was larger than VLPs, and the OVA₂₅₇₋₂₆₄ peptide was located on the surface of VLP(OVA).
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http://dx.doi.org/10.13345/j.cjb.190520DOI Listing
July 2020

Double surfactants-assisted electromembrane extraction of cyromazine and melamine in surface water, soil and cucumber samples followed by capillary electrophoresis with contactless conductivity detection.

J Sci Food Agric 2020 Jan 6;100(1):301-307. Epub 2019 Nov 6.

School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China.

Background: Cyromazine (CYR) and its main degradation product melamine (MEL) are attracting wide attention due to their potential hazards to the environment and humans. In this work, double surfactants-assisted electromembrane extraction (DS-EME) by Tween 20 and alkylated phosphate was firstly used for purification and extraction of CYR and MEL, and the extract was directly analyzed by capillary electrophoresis with capacitively coupled contactless conductivity detection.

Results: Under the optimum conditions, two targets could be well separated from the main interferences, including common biogenic amines and inorganic cations within 14 min. This developed method was successfully applied to the analyses of surface water, soil and cucumber samples, and the average recoveries were in the range 93.3-112%. DS-EME provided a synergistic purification and enrichment effect for CYR and MEL by adding Tween 20 and alkylated phosphate into donor phase and supporting liquid membrane, respectively. Satisfactory limits of detection [0.2-1.5 ng mL , signal-to-noise ratio (S/N) = 3] could be obtained in the tested sample matrices, and the corresponding enrichment factors were up to 115∼123 times.

Conclusion: This developed method provides an alternative for the simultaneous analysis of CYR and MEL in complex real-world samples. © 2019 Society of Chemical Industry.
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http://dx.doi.org/10.1002/jsfa.10039DOI Listing
January 2020

Electrophoretic analysis of polyamines in exhaled breath condensate based on gold-nanoparticles microextraction coupled with field-amplified sample stacking.

Talanta 2019 Jun 5;198:480-486. Epub 2019 Feb 5.

Shanghai Putuo District People's Hospital, Shanghai 200060, China. Electronic address:

In this work, citrate-capped gold-nanoparticles (citrate-AuNPs) have been firstly used for selective extraction of trace polyamines, putrescine (Put) and cadaverine (Cad), followed by field-amplified sample stacking (FASS) coupled with capillary electrophoresis and capacitively coupled contactless conductivity detection (FASS-CE-CD). Put and Cad were extracted by electrostatic attractions between the amine group of the polyamines and the citrate ligands adsorbed on the surfaces of AuNPs. AuNPs microextraction (AuNPs-ME) effectively shortened preparation time (50 min) by introducing ultrasound, and the required sample extraction volume was only 1 mL. Furthermore, a synergistic enrichment strategy based on off-line AuNPs-ME and on-line FASS significantly improved the detection sensitivity, making the enrichment factors up to 1726-1887 times. Under the optimum conditions, Put and Cad could be well separated from the potential coexisting substances and then directly determined by CE-CD without derivatization. Due to its low sample consumption, high sensitivity (LODs: 0.070-0.17 ng mL), and acceptable recoveries (90-105%), this AuNPs-ME/FASS-CE-CD method provides a rapid, economical and eco-friendly approach for direct determination of polyamines in human exhaled breath condensate, and has potential application prospects in preliminary noninvasive diagnosis of oral and respiratory inflammation.
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http://dx.doi.org/10.1016/j.talanta.2019.02.020DOI Listing
June 2019

State-Dependent Spike and Local Field Synchronization between the Thalamic Parafascicular Nucleus and the Dorsal Striatum in a Rat Model of Parkinson's Disease.

Neuroscience 2019 04 19;404:27-38. Epub 2019 Feb 19.

Key laboratory of Animal Resistance Biology of Shandong Province, College of Life Science, Shandong Normal University, Jinan 250014, People's Republic of China. Electronic address:

Recent studies on the impact of Parkinson's disease (PD) on the thalamostriatal pathway have mainly focused on the structural and functional changes in the thalamus projection to the striatum. Alterations in the electrophysiological activity of the thalamostriatal circuit in PD have not been intensively studied. To further investigate this circuit, parafascicular nucleus (PF) single-unit spikes and dorsal striatum local field potential (LFP) activities were simultaneously recorded in control and 6-hydroxydopamine (6-OHDA)-lesioned rats during inattentive rest or treadmill walking states. We classified the PF neurons into two predominant subtypes (PF I and PF II). During rest state, after dopamine loss, increased PF I spike and striatal LFP coherence was observed in the beta-frequency (12-35 Hz), with changed PF I neuronal firing pattern and unchanged firing rates of the two neuron subtypes. However, in a treadmill walking state, PF II neurons displayed markedly increased coherence to striatal beta oscillations in the dopamine-depleted rats, as well as an altered PF II neuronal firing pattern and significantly decreased firing rates of the two neuron subtypes. The results indicate that in PD animals, state transition from rest to moving, such as treadmill walking, is associated with different PF neuron types and increased spike-LFP synchronization, which may provide new paradigms for understanding and treating PD.
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http://dx.doi.org/10.1016/j.neuroscience.2019.01.055DOI Listing
April 2019

Up-regulation of miR-24-1-5p is involved in the chemoprevention of colorectal cancer by black raspberry anthocyanins.

Br J Nutr 2019 09 17;122(5):518-526. Epub 2018 Dec 17.

College of Life Science, Liaoning University, Shenyang 110036, People's Republic of China.

As important epigenetic regulators, microRNA regulate protein expression by triggering the degradation of target mRNA and/or by inhibiting their translation. Dysregulation of microRNA expression has been reported in several cancers, including colorectal cancer. In this study, microRNA-array differential analysis revealed strongly enhanced expression of miR-24-1-5p in the colon tissue of azoxymethane/dextran sulphate sodium-induced mice that were fed with black raspberry anthocyanins for 9 weeks. Overexpression of miR-24-1-5p in human colorectal cancer cells significantly repressed β-catenin expression, and simultaneously decreased cell proliferation, migration and survival. Furthermore, miR-24-1-5p could target β-catenin and trigger a negative regulatory loop for β-catenin and its downstream target genes. β-Catenin signalling is vital to the formation and progression of human colorectal cancer. The current findings therefore identified miR-24-1-5p as a potent regulator of β-catenin, and this may provide a novel chemopreventive and therapeutic strategy for β-catenin signalling-driven colorectal cancer.
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http://dx.doi.org/10.1017/S0007114518003136DOI Listing
September 2019