283 results on '"Mao Xiaobo"'
Search Results
252. α-Synuclein fibril-specific nanobody reduces prion-like α-synuclein spreading in mice.
- Author
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Butler YR, Liu Y, Kumbhar R, Zhao P, Gadhave K, Wang N, Li Y, Mao X, and Wang W
- Subjects
- Animals, Humans, Mice, alpha-Synuclein genetics, alpha-Synuclein metabolism, Lewy Body Disease, Parkinson Disease metabolism, Prions, Synucleinopathies
- Abstract
Pathogenic α-synuclein (α-syn) is a prion-like protein that drives the pathogenesis of Lewy Body Dementia (LBD) and Parkinson's Disease (PD). To target pathogenic α-syn preformed fibrils (PFF), here we designed extracellular disulfide bond-free synthetic nanobody libraries in yeast. Following selection, we identified a nanobody, PFFNB2, that can specifically recognize α-syn PFF over α-syn monomers. PFFNB2 cannot inhibit the aggregation of α-syn monomer, but can significantly dissociate α-syn fibrils. Furthermore, adeno-associated virus (AAV)-encoding EGFP fused to PFFNB2 (AAV-EGFP-PFFNB2) can inhibit PFF-induced α-syn serine 129 phosphorylation (pS129) in mouse primary cortical neurons, and prevent α-syn pathology spreading to the cortex in the transgenic mice expressing human wild type (WT) α-syn by intrastriatal-PFF injection. The pS129 immunoreactivity is negatively correlated with the expression of AAV-EGFP-PFFNB2. In conclusion, PFFNB2 holds a promise for mechanistic exploration and therapeutic development in α-syn-related pathogenesis., (© 2022. The Author(s).)
- Published
- 2022
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253. α-Synuclein Conformational Plasticity: Physiologic States, Pathologic Strains, and Biotechnological Applications.
- Author
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Li A, Rastegar C, and Mao X
- Subjects
- Animals, alpha-Synuclein chemistry, Multiple System Atrophy pathology, Parkinson Disease, Prions, Synucleinopathies
- Abstract
α-Synuclein (αS) is remarkable for both its extensive conformational plasticity and pathologic prion-like properties. Physiologically, αS may populate disordered monomeric, helically folded tetrameric, or membrane-bound oligomeric states. Pathologically, αS may assemble into toxic oligomers and subsequently fibrils, the prion-like transmission of which is implicated in a class of neurodegenerative disorders collectively termed α-synucleinopathies. Notably, αS does not adopt a single "amyloid fold", but rather exists as structurally distinct amyloid-like conformations referred to as "strains". The inoculation of animal models with different strains induces distinct pathologies, and emerging evidence suggests that the propagation of disease-specific strains underlies the differential pathologies observed in patients with different α-synucleinopathies. The characterization of αS strains has provided insight into the structural basis for the overlapping, yet distinct, symptoms of Parkinson's disease, multiple system atrophy, and dementia with Lewy bodies. In this review, we first explore the physiological and pathological differences between conformational states of αS. We then discuss recent studies on the influence of micro-environmental factors on αS species formation, propagation, and the resultant pathological characteristics. Lastly, we review how an understanding of αS conformational properties has been translated to emerging strain amplification technologies, which have provided further insight into the role of specific strains in distinct α-synucleinopathies, and show promise for the early diagnosis of disease.
- Published
- 2022
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254. The Research and Development Thinking on the Status of Artificial Intelligence in Traditional Chinese Medicine.
- Author
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Li N, Yu J, Mao X, Zhao Y, and Huang L
- Abstract
With the rapid development and application of artificial intelligence (AI) in medical field, the diagnostic ways of human health and the social medical structures have changed. Based on the concept of holism and the theory of syndrome differentiation and treatment, TCM realizes comprehensive informatization and intelligence with the help of AI technology in data mining, intelligent diagnosis and treatment, intelligent learning, and decision-making. Furthermore, the intelligent research of TCM technology will further promote the improvement in TCM diagnosis and treatment rules and the leaping development of TCM intelligent instruments. In this article, we performed a systematic review of scientific literature about TCM and AI. Moreover, the practical problems of TCM intellectualization, the current situation and demand of TCM, and the influence of AI in the TCM field are discussed by searching for literature using TCM scientific databases, reference lists, expert consultation, and targeted websites. Finally, we look forward to the application prospects of AI and propose a possible future direction of intelligent TCM in the current health-care system in China., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2022 Nan Li et al.)
- Published
- 2022
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255. Refined Multiscale Entropy Analysis of Wrist Pulse for Gender Difference in Traditional Chinese Medicine among Young Individuals.
- Author
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Xu H, Wang Q, Mao X, Shang Z, Zhao Y, and Huang L
- Abstract
Pulse signal analysis plays an important role in promoting the objectification of traditional Chinese medicine (TCM). Like electrocardiogram (ECG) signals, wrist pulse signals are mainly caused by cardiac activities and are valuable in analyzing cardiac diseases. A large number of studies have reported ECG signals can distinguish gender characteristics of normal healthy subjects using entropy complexity measures, consistently showing more complexity in females than males. No research up to date, however, has been found on examining gender differences with wrist pulse signals of healthy subjects on entropy complexity measures. This paper is aimed to fill in the research gap, which could, in turn, provide a deeper insight into the pulse signal and might identify potential differences between ECG signals and pulse signals. In particular, several complementary entropy measures with corresponding refined composite multiscale versions are established to perform the analysis for the filtered TCM pulse signals. Experimental results reveal that regardless of entropy measures used, there is no statistically significant gender difference in terms of entropy complexity, indicating that the pulse signal holds less gender characteristics than the ECG signal. In view of these findings, wrist pulse signals could be likely to provide different pieces of information to ECG signals. The present study is the first to quantitatively evaluate gender differences in healthy pulse signals with measures of entropy complexity and more importantly; we expect this study could make contribution to the ongoing pulse intelligent diagnosis and objective analysis, further facilitating the modernization of TCM pulse diagnosis., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this paper., (Copyright © 2022 Huaxing Xu et al.)
- Published
- 2022
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256. Edaravone activates the GDNF/RET neurotrophic signaling pathway and protects mRNA-induced motor neurons from iPS cells.
- Author
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Li Q, Feng Y, Xue Y, Zhan X, Fu Y, Gui G, Zhou W, Richard JP, Taga A, Li P, Mao X, Maragakis NJ, and Ying M
- Subjects
- Edaravone metabolism, Edaravone pharmacology, Edaravone therapeutic use, Glial Cell Line-Derived Neurotrophic Factor metabolism, Glial Cell Line-Derived Neurotrophic Factor pharmacology, Glial Cell Line-Derived Neurotrophic Factor therapeutic use, Humans, Hydrogen Peroxide metabolism, Hydrogen Peroxide pharmacology, Hydrogen Peroxide therapeutic use, Motor Neurons metabolism, Proto-Oncogene Proteins c-ret metabolism, Proto-Oncogene Proteins c-ret therapeutic use, RNA, Messenger metabolism, Signal Transduction, Amyotrophic Lateral Sclerosis drug therapy, Amyotrophic Lateral Sclerosis metabolism, Induced Pluripotent Stem Cells
- Abstract
Background: Spinal cord motor neurons (MNs) from human iPS cells (iPSCs) have wide applications in disease modeling and therapeutic development for amyotrophic lateral sclerosis (ALS) and other MN-associated neurodegenerative diseases. We need highly efficient MN differentiation strategies for generating iPSC-derived disease models that closely recapitulate the genetic and phenotypic complexity of ALS. An important application of these models is to understand molecular mechanisms of action of FDA-approved ALS drugs that only show modest clinical efficacy. Novel mechanistic insights will help us design optimal therapeutic strategies together with predictive biomarkers to achieve better efficacy., Methods: We induce efficient MN differentiation from iPSCs in 4 days using synthetic mRNAs coding two transcription factors (Ngn2 and Olig2) with phosphosite modification. These MNs after extensive characterization were applied in electrophysiological and neurotoxicity assays as well as transcriptomic analysis, to study the neuroprotective effect and molecular mechanisms of edaravone, an FDA-approved drug for ALS, for improving its clinical efficacy., Results: We generate highly pure and functional mRNA-induced MNs (miMNs) from control and ALS iPSCs, as well as embryonic stem cells. Edaravone alleviates H
2 O2 -induced neurotoxicity and electrophysiological dysfunction in miMNs, demonstrating its neuroprotective effect that was also found in the glutamate-induced miMN neurotoxicity model. Guided by the transcriptomic analysis, we show a previously unrecognized effect of edaravone to induce the GDNF receptor RET and the GDNF/RET neurotrophic signaling in vitro and in vivo, suggesting a clinically translatable strategy to activate this key neuroprotective signaling. Notably, edaravone can replace required neurotrophic factors (BDNF and GDNF) to support long-term miMN survival and maturation, further supporting the neurotrophic function of edaravone-activated signaling. Furthermore, we show that edaravone and GDNF combined treatment more effectively protects miMNs from H2 O2 -induced neurotoxicity than single treatment, suggesting a potential combination strategy for ALS treatment., Conclusions: This study provides methodology to facilitate iPSC differentiation and disease modeling. Our discoveries will facilitate the development of optimal edaravone-based therapies for ALS and potentially other neurodegenerative diseases., (© 2022. The Author(s).)- Published
- 2022
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257. Early Wound Repair Versus Later Scar Repair in Children with Treadmill Hand Friction Burns.
- Author
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Zhou R, Qiu L, Xiao J, Mao X, and Yuan X
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- Burn Units, Child, Child, Preschool, Cicatrix etiology, Debridement, Drainage, Female, Friction, Humans, Male, Retrospective Studies, Skin Transplantation, Surveys and Questionnaires, Wound Healing, Burns etiology, Burns therapy, Cicatrix therapy, Hand Injuries etiology, Hand Injuries therapy, Sports Equipment
- Abstract
The incidence of pediatric treadmill hand friction burns has been increasing every year. The injuries are deeper than thermal hand burns, the optimal treatment remains unclear. This was a retrospective study of children who received surgery for treadmill hand friction burns from January 1, 2015, to December 31, 2019, in a single burn center. A total of 22 children were surveyed. The patients were naturally divided into two groups: the wound repair group (13 patients), which was admitted early to the hospital after injury and received debridement and vacuum sealing drainage initially, and a full-thickness skin graft later; and the scar repair group (nine patients), in which a scar contracture developed as a result of wound healing and received scar release and skin grafting later. The Modified Michigan Hand Questionnaire score in the wound repair group was 116.31 ± 10.55, and the corresponding score in the scar repair group was 117.56 ± 8.85 (p > .05), no statistically significant difference. The Vancouver Scar Scale score in the wound repair group was 4.15 ± 1.21, and the corresponding score in the scar repair group was 7.22 ± 1.09 (p < .05). Parents were satisfied with the postoperative appearance and function of the hand. None in the two groups required secondary surgery. If the burns are deep second degree, third degree, or infected, early debridement, vacuum sealing drainage initially, and a full-thickness skin graft can obviously relieve pediatric pain, shorten the course of the disease, and restore the function of the hand as soon as possible., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Burn Association. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2022
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258. TRIP12 ubiquitination of glucocerebrosidase contributes to neurodegeneration in Parkinson's disease.
- Author
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Seo BA, Kim D, Hwang H, Kim MS, Ma SX, Kwon SH, Kweon SH, Wang H, Yoo JM, Choi S, Kwon SH, Kang SU, Kam TI, Kim K, Karuppagounder SS, Kang BG, Lee S, Park H, Kim S, Yan W, Li YS, Kuo SH, Redding-Ochoa J, Pletnikova O, Troncoso JC, Lee G, Mao X, Dawson VL, Dawson TM, and Ko HS
- Subjects
- Animals, Brain metabolism, Disease Models, Animal, Mice, Ubiquitination, alpha-Synuclein metabolism, Carrier Proteins metabolism, Glucosylceramidase genetics, Glucosylceramidase metabolism, Parkinson Disease genetics, Parkinson Disease metabolism, Ubiquitin-Protein Ligases metabolism
- Abstract
Impairment in glucocerebrosidase (GCase) is strongly associated with the development of Parkinson's disease (PD), yet the regulators responsible for its impairment remain elusive. In this paper, we identify the E3 ligase Thyroid Hormone Receptor Interacting Protein 12 (TRIP12) as a key regulator of GCase. TRIP12 interacts with and ubiquitinates GCase at lysine 293 to control its degradation via ubiquitin proteasomal degradation. Ubiquitinated GCase by TRIP12 leads to its functional impairment through premature degradation and subsequent accumulation of α-synuclein. TRIP12 overexpression causes mitochondrial dysfunction, which is ameliorated by GCase overexpression. Further, conditional TRIP12 knockout in vitro and knockdown in vivo promotes the expression of GCase, which blocks α-synuclein preformed fibrils (α-syn PFFs)-provoked dopaminergic neurodegeneration. Moreover, TRIP12 accumulates in human PD brain and α-synuclein-based mouse models. The identification of TRIP12 as a regulator of GCase provides a new perspective on the molecular mechanisms underlying dysfunctional GCase-driven neurodegeneration in PD., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021 Elsevier Inc. All rights reserved.)
- Published
- 2021
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259. Interpretation of Electrocardiogram Heartbeat by CNN and GRU.
- Author
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Yao G, Mao X, Li N, Xu H, Xu X, Jiao Y, and Ni J
- Subjects
- Algorithms, Computational Biology, Databases, Factual statistics & numerical data, Deep Learning, Heart Rate, Humans, Monitoring, Ambulatory statistics & numerical data, Signal Processing, Computer-Assisted, Wavelet Analysis, Wearable Electronic Devices statistics & numerical data, Arrhythmias, Cardiac classification, Arrhythmias, Cardiac diagnosis, Diagnosis, Computer-Assisted statistics & numerical data, Electrocardiography classification, Electrocardiography statistics & numerical data, Neural Networks, Computer
- Abstract
The diagnosis of electrocardiogram (ECG) is extremely onerous and inefficient, so it is necessary to use a computer-aided diagnosis of ECG signals. However, it is still a challenging problem to design high-accuracy ECG algorithms suitable for the medical field. In this paper, a classification method is proposed to classify ECG signals. Firstly, wavelet transform is used to denoise the original data, and data enhancement technology is used to overcome the problem of an unbalanced dataset. Secondly, an integrated convolutional neural network (CNN) and gated recurrent unit (GRU) classifier is proposed. The proposed network consists of a convolution layer, followed by 6 local feature extraction modules (LFEM), a GRU, and a Dense layer and a Softmax layer. Finally, the processed data were input into the CNN-GRU network into five categories: nonectopic beats, supraventricular ectopic beats, ventricular ectopic beats, fusion beats, and unknown beats. The MIT-BIH arrhythmia database was used to evaluate the approach, and the average sensitivity, accuracy, and F1-score of the network for 5 types of ECG were 99.33%, 99.61%, and 99.42%. The evaluation criteria of the proposed method are superior to other state-of-the-art methods, and this model can be applied to wearable devices to achieve high-precision monitoring of ECG., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2021 Guoliang Yao et al.)
- Published
- 2021
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260. Mechanistic basis for receptor-mediated pathological α-synuclein fibril cell-to-cell transmission in Parkinson's disease.
- Author
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Zhang S, Liu YQ, Jia C, Lim YJ, Feng G, Xu E, Long H, Kimura Y, Tao Y, Zhao C, Wang C, Liu Z, Hu JJ, Ma MR, Liu Z, Jiang L, Li D, Wang R, Dawson VL, Dawson TM, Li YM, Mao X, and Liu C
- Subjects
- Animals, Cell Line, Tumor, Endocytosis, Humans, Mice, Nerve Degeneration pathology, Neurons metabolism, Phosphorylation, Phosphoserine metabolism, Protein Binding, Static Electricity, alpha-Synuclein chemistry, alpha-Synuclein toxicity, Lymphocyte Activation Gene 3 Protein, Amyloid metabolism, Amyloid beta-Protein Precursor metabolism, Antigens, CD metabolism, Parkinson Disease metabolism, Parkinson Disease pathology, alpha-Synuclein metabolism
- Abstract
The spread of pathological α-synuclein (α-syn) is a crucial event in the progression of Parkinson's disease (PD). Cell surface receptors such as lymphocyte activation gene 3 (LAG3) and amyloid precursor-like protein 1 (APLP1) can preferentially bind α-syn in the amyloid over monomeric state to initiate cell-to-cell transmission. However, the molecular mechanism underlying this selective binding is unknown. Here, we perform an array of biophysical experiments and reveal that LAG3 D1 and APLP1 E1 domains commonly use an alkaline surface to bind the acidic C terminus, especially residues 118 to 140, of α-syn. The formation of amyloid fibrils not only can disrupt the intramolecular interactions between the C terminus and the amyloid-forming core of α-syn but can also condense the C terminus on fibril surface, which remarkably increase the binding affinity of α-syn to the receptors. Based on this mechanism, we find that phosphorylation at serine 129 (pS129), a hallmark modification of pathological α-syn, can further enhance the interaction between α-syn fibrils and the receptors. This finding is further confirmed by the higher efficiency of pS129 fibrils in cellular internalization, seeding, and inducing PD-like α-syn pathology in transgenic mice. Our work illuminates the mechanistic understanding on the spread of pathological α-syn and provides structural information for therapeutic targeting on the interaction of α-syn fibrils and receptors as a potential treatment for PD., Competing Interests: The authors declare no competing interest.
- Published
- 2021
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261. Dysregulated miRNAs mark Parkinson's disease progression.
- Author
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Rosenthal LS, Yang J, and Mao X
- Subjects
- Humans, Transcriptome, Disease Progression, High-Throughput Nucleotide Sequencing, MicroRNAs genetics, Parkinson Disease genetics, RNA, Small Untranslated
- Published
- 2021
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262. Few-shot pulse wave contour classification based on multi-scale feature extraction.
- Author
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Lu P, Liu C, Mao X, Zhao Y, Wang H, Zhang H, and Guo L
- Abstract
The annotation procedure of pulse wave contour (PWC) is expensive and time-consuming, thereby hindering the formation of large-scale datasets to match the requirements of deep learning. To obtain better results under the condition of few-shot PWC, a small-parameter unit structure and a multi-scale feature-extraction model are proposed. In the small-parameter unit structure, information of adjacent cells is transmitted through state variables. Simultaneously, a forgetting gate is used to update the information and retain long-term dependence of PWC in the form of unit series. The multi-scale feature-extraction model is an integrated model containing three parts. Convolution neural networks are used to extract spatial features of single-period PWC and rhythm features of multi-period PWC. Recursive neural networks are used to retain the long-term dependence features of PWC. Finally, an inference layer is used for classification through extracted features. Classification experiments of cardiovascular diseases are performed on photoplethysmography dataset and continuous non-invasive blood pressure dataset. Results show that the classification accuracy of the multi-scale feature-extraction model on the two datasets respectively can reach 80% and 96%, respectively.
- Published
- 2021
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263. RIP3-mediated necroptosis was essential for spiral ganglion neuron damage.
- Author
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Wang X, Mao X, Liang K, Chen X, Yue B, and Yang Y
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- Animals, Cell Survival drug effects, Cell Survival physiology, Dose-Response Relationship, Drug, Enzyme Inhibitors pharmacology, Female, Male, Necroptosis drug effects, Neurons drug effects, Neurons pathology, Ouabain pharmacology, Rats, Rats, Sprague-Dawley, Receptor-Interacting Protein Serine-Threonine Kinases antagonists & inhibitors, Spiral Ganglion drug effects, Spiral Ganglion pathology, Necroptosis physiology, Neurons metabolism, Receptor-Interacting Protein Serine-Threonine Kinases biosynthesis, Spiral Ganglion metabolism
- Abstract
To identify the role of RIP3 in ouabain-induced necroptosis and offer clinical implications to prevent spiral ganglion neurons (SGNs) from death, ouabain was applied in SGNs derived from fetal rats and injected into Sprague-Dawley rats to construct injury model in vitro and in vivo, respectively. The necroptosis rate of SGNs was determined by flow cytometry and MTT assays. The protein levels and phosphorylation of RIP3 were evaluated using western blotting and immunofluorescence. SGNs injury was observed using H&E staining and immunofluorescence. The hearing function of rats was evaluated by the auditory brainstem response (ABR) and Distortion Product Otoacoustic Emissions (DPOAE) methods. Ouabain caused dose-dependent necroptosis in SGNs and significant loss of SGNs of the cochlear axis in vivo. RIP3 and pRIP3 were upregulated with SGNs injury promoted, and RIP3 overexpression promoted ouabain-induced necroptosis in SGNs in vitro, which could be suppressed by necrostatin-1. RIP3 knockdown inhibited ouabain-induced necroptosis and reduced the phosphorylation of MLKL but no RIP3-dependent effect on the level of MLKL. RIP3 inhibition in vivo protected rats from ouabain-induced hearing damage with reducing ABR threshold shifts and promoting DPOAE amplitudes, while overexpression of RIP3 enhanced ouabain-induced injury that could be partially reversed by necrostatin-1. A decrease of SGNs density and an upregulation of pRIP3 were observed with RIP3 overexpression, which was in contrast when RIP3 was silenced. Therefore, RIP3 was essential for mediating necroptosis in ouabain-induced SGNs damage. Targeting RIP3 may prevent SGNs from death in clinical practice, and finally help the treatment of sensorineural hearing loss., (Copyright © 2020 Elsevier B.V. All rights reserved.)
- Published
- 2021
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264. The Diagonal Branch to the Accompanying Vein Fistula After Rotational Atherectomy.
- Author
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Yi G, Jin D, Li Z, and Mao X
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- Aged, Arteriovenous Fistula diagnosis, Coronary Angiography, Coronary Stenosis diagnosis, Humans, Male, Vascular Calcification diagnosis, Arteriovenous Fistula etiology, Atherectomy, Coronary adverse effects, Coronary Stenosis surgery, Coronary Vessels diagnostic imaging, Vascular Calcification surgery
- Abstract
We report a case of rotational-atherectomy induced fistula between the diagonal branch and the accompanying vein. Thus far, the patient has had no relevant symptoms; thus, no intervention has been undertaken. We will closely monitor the patient to determine future treatment.
- Published
- 2019
265. Circulating myocardial microRNAs from infarcted hearts are carried in exosomes and mobilise bone marrow progenitor cells.
- Author
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Cheng M, Yang J, Zhao X, Zhang E, Zeng Q, Yu Y, Yang L, Wu B, Yi G, Mao X, Huang K, Dong N, Xie M, Limdi NA, Prabhu SD, Zhang J, and Qin G
- Subjects
- Aged, Animals, Down-Regulation, Exosomes metabolism, Female, Hematopoietic Stem Cell Mobilization, Hematopoietic Stem Cells pathology, Humans, Male, Mice, Mice, Inbred C57BL, MicroRNAs metabolism, Middle Aged, Myocardial Infarction metabolism, Myocardial Infarction pathology, Receptors, CXCR4 metabolism, Hematopoietic Stem Cells metabolism, MicroRNAs blood, Myocardial Infarction blood, Myocardium metabolism
- Abstract
Myocardial microRNAs (myo-miRs) are released into the circulation after acute myocardial infarction (AMI). How they impact remote organs is however largely unknown. Here we show that circulating myo-miRs are carried in exosomes and mediate functional crosstalk between the ischemic heart and the bone marrow (BM). In mice, we find that AMI is accompanied by an increase in circulating levels of myo-miRs, with miR-1, 208, and 499 predominantly in circulating exosomes and miR-133 in the non-exosomal component. Myo-miRs are imported selectively to peripheral organs and preferentially to the BM. Exosomes mediate the transfer of myo-miRs to BM mononuclear cells (MNCs), where myo-miRs downregulate CXCR4 expression. Injection of exosomes isolated from AMI mice into wild-type mice downregulates CXCR4 expression in BM-MNCs and increases the number of circulating progenitor cells. Thus, we propose that myo-miRs carried in circulating exosomes allow a systemic response to cardiac injury that may be leveraged for cardiac repair.
- Published
- 2019
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266. Poly(ADP-ribose) drives pathologic α-synuclein neurodegeneration in Parkinson's disease.
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Kam TI, Mao X, Park H, Chou SC, Karuppagounder SS, Umanah GE, Yun SP, Brahmachari S, Panicker N, Chen R, Andrabi SA, Qi C, Poirier GG, Pletnikova O, Troncoso JC, Bekris LM, Leverenz JB, Pantelyat A, Ko HS, Rosenthal LS, Dawson TM, and Dawson VL
- Subjects
- Animals, Benzimidazoles pharmacology, Brain metabolism, Brain pathology, Cell Death, Dopaminergic Neurons metabolism, Dopaminergic Neurons pathology, Enzyme Activation, Gene Knockout Techniques, Mice, Mice, Inbred C57BL, Mice, Knockout, Nitric Oxide metabolism, Poly (ADP-Ribose) Polymerase-1 antagonists & inhibitors, Poly (ADP-Ribose) Polymerase-1 genetics, Poly(ADP-ribose) Polymerase Inhibitors pharmacology, Recombinant Proteins genetics, Recombinant Proteins metabolism, alpha-Synuclein genetics, Parkinson Disease metabolism, Parkinson Disease pathology, Poly (ADP-Ribose) Polymerase-1 metabolism, Poly Adenosine Diphosphate Ribose metabolism, alpha-Synuclein metabolism
- Abstract
The pathologic accumulation and aggregation of α-synuclein (α-syn) underlies Parkinson's disease (PD). The molecular mechanisms by which pathologic α-syn causes neurodegeneration in PD are not known. Here, we found that pathologic α-syn activates poly(adenosine 5'-diphosphate-ribose) (PAR) polymerase-1 (PARP-1), and PAR generation accelerates the formation of pathologic α-syn, resulting in cell death via parthanatos. PARP inhibitors or genetic deletion of PARP-1 prevented pathologic α-syn toxicity. In a feed-forward loop, PAR converted pathologic α-syn to a more toxic strain. PAR levels were increased in the cerebrospinal fluid and brains of patients with PD, suggesting that PARP activation plays a role in PD pathogenesis. Thus, strategies aimed at inhibiting PARP-1 activation could hold promise as a disease-modifying therapy to prevent the loss of dopamine neurons in PD., (Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)
- Published
- 2018
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267. Block of A1 astrocyte conversion by microglia is neuroprotective in models of Parkinson's disease.
- Author
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Yun SP, Kam TI, Panicker N, Kim S, Oh Y, Park JS, Kwon SH, Park YJ, Karuppagounder SS, Park H, Kim S, Oh N, Kim NA, Lee S, Brahmachari S, Mao X, Lee JH, Kumar M, An D, Kang SU, Lee Y, Lee KC, Na DH, Kim D, Lee SH, Roschke VV, Liddelow SA, Mari Z, Barres BA, Dawson VL, Lee S, Dawson TM, and Ko HS
- Subjects
- Amyloid metabolism, Animals, Disease Models, Animal, Humans, Mice, Inbred C57BL, Mice, Transgenic, alpha-Synuclein metabolism, Astrocytes pathology, Microglia pathology, Neuroprotective Agents metabolism, Parkinson Disease pathology
- Abstract
Activation of microglia by classical inflammatory mediators can convert astrocytes into a neurotoxic A1 phenotype in a variety of neurological diseases
1,2 . Development of agents that could inhibit the formation of A1 reactive astrocytes could be used to treat these diseases for which there are no disease-modifying therapies. Glucagon-like peptide-1 receptor (GLP1R) agonists have been indicated as potential neuroprotective agents for neurologic disorders such as Alzheimer's disease and Parkinson's disease3-13 . The mechanisms by which GLP1R agonists are neuroprotective are not known. Here we show that a potent, brain-penetrant long-acting GLP1R agonist, NLY01, protects against the loss of dopaminergic neurons and behavioral deficits in the α-synuclein preformed fibril (α-syn PFF) mouse model of sporadic Parkinson's disease14,15 . NLY01 also prolongs the life and reduces the behavioral deficits and neuropathological abnormalities in the human A53T α-synuclein (hA53T) transgenic mouse model of α-synucleinopathy-induced neurodegeneration16 . We found that NLY01 is a potent GLP1R agonist with favorable properties that is neuroprotective through the direct prevention of microglial-mediated conversion of astrocytes to an A1 neurotoxic phenotype. In light of its favorable properties, NLY01 should be evaluated in the treatment of Parkinson's disease and related neurologic disorders characterized by microglial activation.- Published
- 2018
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268. Robust kinase- and age-dependent dopaminergic and norepinephrine neurodegeneration in LRRK2 G2019S transgenic mice.
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Xiong Y, Neifert S, Karuppagounder SS, Liu Q, Stankowski JN, Lee BD, Ko HS, Lee Y, Grima JC, Mao X, Jiang H, Kang SU, Swing DA, Iacovitti L, Tessarollo L, Dawson TM, and Dawson VL
- Subjects
- Age Factors, Animals, Behavior, Animal, Dopaminergic Neurons metabolism, Humans, Male, Mice, Mice, Transgenic, Motor Activity, Mutation, Neurodegenerative Diseases metabolism, alpha-Synuclein metabolism, Disease Models, Animal, Dopamine metabolism, Dopaminergic Neurons pathology, Leucine-Rich Repeat Serine-Threonine Protein Kinase-2 physiology, Neurodegenerative Diseases pathology, Norepinephrine metabolism
- Abstract
Mutations in LRRK2 are known to be the most common genetic cause of sporadic and familial Parkinson's disease (PD). Multiple lines of LRRK2 transgenic or knockin mice have been developed, yet none exhibit substantial dopamine (DA)-neuron degeneration. Here we develop human tyrosine hydroxylase (TH) promoter-controlled tetracycline-sensitive LRRK2 G2019S (GS) and LRRK2 G2019S kinase-dead (GS/DA) transgenic mice and show that LRRK2 GS expression leads to an age- and kinase-dependent cell-autonomous neurodegeneration of DA and norepinephrine (NE) neurons. Accompanying the loss of DA neurons are DA-dependent behavioral deficits and α-synuclein pathology that are also LRRK2 GS kinase-dependent. Transmission EM reveals that that there is an LRRK2 GS kinase-dependent significant reduction in synaptic vesicle number and a greater abundance of clathrin-coated vesicles in DA neurons. These transgenic mice indicate that LRRK2-induced DA and NE neurodegeneration is kinase-dependent and can occur in a cell-autonomous manner. Moreover, these mice provide a substantial advance in animal model development for LRRK2-associated PD and an important platform to investigate molecular mechanisms for how DA neurons degenerate as a result of expression of mutant LRRK2., Competing Interests: The authors declare no conflict of interest.
- Published
- 2018
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269. GBA1 deficiency negatively affects physiological α-synuclein tetramers and related multimers.
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Kim S, Yun SP, Lee S, Umanah GE, Bandaru VVR, Yin X, Rhee P, Karuppagounder SS, Kwon SH, Lee H, Mao X, Kim D, Pandey A, Lee G, Dawson VL, Dawson TM, and Ko HS
- Subjects
- 1-Deoxynojirimycin analogs & derivatives, Cell Line, Tumor, Glucosylceramidase genetics, Humans, Protein Multimerization, Dopaminergic Neurons metabolism, Glucosylceramidase deficiency, Glycosphingolipids metabolism, Parkinson Disease metabolism, alpha-Synuclein metabolism
- Abstract
Accumulating evidence suggests that α-synuclein (α-syn) occurs physiologically as a helically folded tetramer that resists aggregation. However, the mechanisms underlying the regulation of formation of α-syn tetramers are still mostly unknown. Cellular membrane lipids are thought to play an important role in the regulation of α-syn tetramer formation. Since glucocerebrosidase 1 (GBA1) deficiency contributes to the aggregation of α-syn and leads to changes in neuronal glycosphingolipids (GSLs) including gangliosides, we hypothesized that GBA1 deficiency may affect the formation of α-syn tetramers. Here, we show that accumulation of GSLs due to GBA1 deficiency decreases α-syn tetramers and related multimers and increases α-syn monomers in CRISPR-GBA1 knockout (KO) SH-SY5Y cells. Moreover, α-syn tetramers and related multimers are decreased in N370S GBA1 Parkinson's disease (PD) induced pluripotent stem cell (iPSC)-derived human dopaminergic (hDA) neurons and murine neurons carrying the heterozygous L444P GBA1 mutation. Treatment with miglustat to reduce GSL accumulation and overexpression of GBA1 to augment GBA1 activity reverse the destabilization of α-syn tetramers and protect against α-syn preformed fibril-induced toxicity in hDA neurons. Taken together, these studies provide mechanistic insights into how GBA1 regulates the transition from monomeric α-syn to α-syn tetramers and multimers and suggest unique therapeutic opportunities for PD and dementia with Lewy bodies., Competing Interests: The authors declare no conflict of interest.
- Published
- 2018
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270. Thorase variants are associated with defects in glutamatergic neurotransmission that can be rescued by Perampanel.
- Author
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Umanah GKE, Pignatelli M, Yin X, Chen R, Crawford J, Neifert S, Scarffe L, Behensky AA, Guiberson N, Chang M, Ma E, Kim JW, Castro CC, Mao X, Chen L, Andrabi SA, Pletnikov MV, Pulver AE, Avramopoulos D, Bonci A, Valle D, Dawson TM, and Dawson VL
- Subjects
- ATPases Associated with Diverse Cellular Activities metabolism, Adenosine Triphosphatases metabolism, Animals, Behavior, Animal, Cells, Cultured, Cerebral Cortex pathology, Endocytosis drug effects, Excitatory Postsynaptic Potentials drug effects, Heterozygote, Humans, Memory drug effects, Mice, Neurons drug effects, Neurons metabolism, Nitriles, Protein Multimerization, Social Behavior, ATPases Associated with Diverse Cellular Activities genetics, Genetic Variation, Glutamates metabolism, Pyridones pharmacology, Synaptic Transmission drug effects
- Abstract
The AAA+ adenosine triphosphatase (ATPase) Thorase plays a critical role in controlling synaptic plasticity by regulating the expression of surface α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs). Bidirectional sequencing of exons of ATAD1 , the gene encoding Thorase, in a cohort of patients with schizophrenia and healthy controls revealed rare Thorase variants. These variants caused defects in glutamatergic signaling by impairing AMPAR internalization and recycling in mouse primary cortical neurons. This contributed to increased surface expression of the AMPAR subunit GluA2 and enhanced synaptic transmission. Heterozygous Thorase-deficient mice engineered to express these Thorase variants showed altered synaptic transmission and several behavioral deficits compared to heterozygous Thorase-deficient mice expressing wild-type Thorase. These behavioral impairments were rescued by the competitive AMPAR antagonist Perampanel, a U.S. Food and Drug Administration-approved drug. These findings suggest that Perampanel may be useful for treating disorders involving compromised AMPAR-mediated glutamatergic neurotransmission., (Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)
- Published
- 2017
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271. High-Content Genome-Wide RNAi Screen Reveals CCR3 as a Key Mediator of Neuronal Cell Death.
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Zhang J, Wang H, Sherbini O, Ling-Lin Pai E, Kang SU, Kwon JS, Yang J, He W, Wang H, Eacker SM, Chi Z, Mao X, Xu J, Jiang H, Andrabi SA, Dawson TM, and Dawson VL
- Subjects
- Animals, Brain metabolism, Brain pathology, Cell Death drug effects, Cell Hypoxia physiology, Cells, Cultured, Computational Biology, Disease Models, Animal, Glucose deficiency, Infarction, Middle Cerebral Artery, Male, Methylnitronitrosoguanidine toxicity, Mice, Knockout, Motor Activity physiology, Neural Stem Cells drug effects, Neural Stem Cells metabolism, Neurons drug effects, Neurons pathology, RNA Interference, Receptors, CCR3 antagonists & inhibitors, Receptors, CCR3 genetics, Stroke metabolism, Stroke pathology, Cell Death physiology, Neurons metabolism, Receptors, CCR3 metabolism
- Abstract
Neuronal loss caused by ischemic injury, trauma, or disease can lead to devastating consequences for the individual. With the goal of limiting neuronal loss, a number of cell death pathways have been studied, but there may be additional contributors to neuronal death that are yet unknown. To identify previously unknown cell death mediators, we performed a high-content genome-wide screening of short, interfering RNA (siRNA) with an siRNA library in murine neural stem cells after exposure to N -methyl- N -nitroso- N '-nitroguanidine (MNNG), which leads to DNA damage and cell death. Eighty genes were identified as key mediators for cell death. Among them, 14 are known cell death mediators and 66 have not previously been linked to cell death pathways. Using an integrated approach with functional and bioinformatics analysis, we provide possible molecular networks, interconnected pathways, and/or protein complexes that may participate in cell death. Of the 66 genes, we selected CCR3 for further evaluation and found that CCR3 is a mediator of neuronal injury. CCR3 inhibition or deletion protects murine cortical cultures from oxygen-glucose deprivation-induced cell death, and CCR3 deletion in mice provides protection from ischemia in vivo. Taken together, our findings suggest that CCR3 is a previously unknown mediator of cell death. Future identification of the neural cell death network in which CCR3 participates will enhance our understanding of the molecular mechanisms of neural cell death., Competing Interests: Authors report no conflict of interest.
- Published
- 2016
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272. Pathological α-synuclein transmission initiated by binding lymphocyte-activation gene 3.
- Author
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Mao X, Ou MT, Karuppagounder SS, Kam TI, Yin X, Xiong Y, Ge P, Umanah GE, Brahmachari S, Shin JH, Kang HC, Zhang J, Xu J, Chen R, Park H, Andrabi SA, Kang SU, Gonçalves RA, Liang Y, Zhang S, Qi C, Lam S, Keiler JA, Tyson J, Kim D, Panicker N, Yun SP, Workman CJ, Vignali DA, Dawson VL, Ko HS, and Dawson TM
- Subjects
- Animals, Dopaminergic Neurons metabolism, Endocytosis, Humans, Mice, Mice, Transgenic, Protein Binding, Protein Transport, alpha-Synuclein genetics, Lymphocyte Activation Gene 3 Protein, Antigens, CD metabolism, Parkinson Disease metabolism, alpha-Synuclein metabolism
- Abstract
Emerging evidence indicates that the pathogenesis of Parkinson's disease (PD) may be due to cell-to-cell transmission of misfolded preformed fibrils (PFF) of α-synuclein (α-syn). The mechanism by which α-syn PFF spreads from neuron to neuron is not known. Here, we show that LAG3 (lymphocyte-activation gene 3) binds α-syn PFF with high affinity (dissociation constant = 77 nanomolar), whereas the α-syn monomer exhibited minimal binding. α-Syn-biotin PFF binding to LAG3 initiated α-syn PFF endocytosis, transmission, and toxicity. Lack of LAG3 substantially delayed α-syn PFF-induced loss of dopamine neurons, as well as biochemical and behavioral deficits in vivo. The identification of LAG3 as a receptor that binds α-syn PFF provides a target for developing therapeutics designed to slow the progression of PD and related α-synucleinopathies., (Copyright © 2016, American Association for the Advancement of Science.)
- Published
- 2016
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273. Digoxin reduces atherosclerosis in apolipoprotein E-deficient mice.
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Shi H, Mao X, Zhong Y, Liu Y, Zhao X, Yu K, Zhu R, Wei Y, Zhu J, Sun H, Mao Y, and Zeng Q
- Subjects
- Animals, Apolipoproteins E metabolism, Atherosclerosis immunology, Atherosclerosis metabolism, Digoxin blood, Digoxin metabolism, Dose-Response Relationship, Drug, Inflammation drug therapy, Inflammation immunology, Interleukin-17 immunology, Mice, Mice, Inbred C57BL, Mice, Knockout, Nuclear Receptor Subfamily 1, Group F, Member 3 antagonists & inhibitors, Apolipoproteins E deficiency, Atherosclerosis drug therapy, Digoxin pharmacology
- Abstract
Background and Purpose: Numerous in vitro studies have suggested that digoxin suppresses inflammation and alters lipid metabolism. However, the effect of dioxin on atherosclerosis is poorly understood. The present study was conducted to determine whether digoxin affects the development of atherosclerosis in a murine model of atherosclerotic disease., Experimental Approach: Apolipoprotein E-deficient mice maintained on a Western-type diet were administered PBS (control), low-dose digoxin (1 mg · kg(-1) · day(-1)) or high-dose digoxin (2 mg · kg(-1) · day(-1)) via i.p. injection for 12 weeks., Key Results: Digoxin dose-dependently reduced atherosclerotic lesion formation and plasma lipid levels (reductions of 41% in total cholesterol, 54% in triglycerides and 20% in low-density lipoprotein cholesterol in the high-dose digoxin-treated group). Moreover, treatment with digoxin markedly attenuated IL-17A expression and IL-17A-related inflammatory responses and increased the abundance of regulatory T cells (Tregs)., Conclusions and Implications: Our data demonstrate that digoxin acts as a specific antagonist of retinoid-related orphan receptor-γ to decrease atherosclerosis by suppressing lipid levels and IL-17A-related inflammatory responses., (© 2016 The British Pharmacological Society.)
- Published
- 2016
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274. Disruption of the TSLP-TSLPR-LAP signaling between epithelial and dendritic cells through hyperlipidemia contributes to regulatory T-Cell defects in atherosclerotic mice.
- Author
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Yu K, Dong Q, Mao X, Meng K, Zhao X, Ji Q, Wu B, Zhong Y, Zhu Z, Liu Y, Zhang W, Tony H, Shi H, and Zeng Q
- Subjects
- Animals, Apolipoproteins E deficiency, Apolipoproteins E genetics, Atherosclerosis genetics, Atherosclerosis immunology, Atherosclerosis pathology, Cell Differentiation, Cells, Cultured, Coculture Techniques, Cytokines administration & dosage, Dendritic Cells metabolism, Disease Models, Animal, Epithelial Cells immunology, Forkhead Transcription Factors metabolism, Hyperlipidemias genetics, Hyperlipidemias immunology, Hyperlipidemias pathology, Immune Tolerance, Lipoproteins, LDL metabolism, Mice, Inbred C57BL, Mice, Knockout, Peptides isolation & purification, Receptors, Cytokine agonists, Spleen immunology, Spleen metabolism, T-Lymphocytes, Regulatory immunology, Thymus Gland immunology, Thymus Gland metabolism, Thymic Stromal Lymphopoietin, Atherosclerosis metabolism, Cell Communication drug effects, Cytokines metabolism, Dendritic Cells immunology, Epithelial Cells metabolism, Hyperlipidemias metabolism, Immunoglobulins metabolism, Peptides metabolism, Receptors, Cytokine metabolism, Signal Transduction drug effects, T-Lymphocytes, Regulatory metabolism
- Abstract
Regulatory T-Cells (Tregs) play a protective role against the development of atherosclerosis. Moreover, thymic stromal lymphopoietin (TSLP)/thymic stromal lymphopoietin receptor (TSLPR) signaling in myeloid dendritic cells (DCs) promote Treg differentiation. Here, we examined the potential role of TSLP/TSLPR on Treg homeostasis in atherosclerosis. The frequencies of both latency-associated peptide (LAP)(+) and Foxp3(+) Tregs were reduced in the thymus and spleen of ApoE(-/-) mice compared with C57BL/6 mice, and this effect was associated with decreased thymic output. The tolerogenic function of DCs obtained from ApoE(-/-) mice was compromised compared with those from C57BL/6 mice. The expression of TSLP and TSLPR was also inhibited in ApoE(-/-) mice. In addition, we found that ox-LDL attenuated TSLP expression in cultured thymic epithelial cells (TECs) through the activation of retinoid X receptor alpha (RXRA) and IL-1β and decreased LAP and PD-L1 expression in oxLDL-activated DCs while both were up-regulated in TSLP-activated DCs. We also observed that the TSLP-DCs mediated differentiation of Tregs was abrogated through LAP neutralization. Furthermore, TSLP injection rescued Treg defects in ApoE(-/-) mice. These findings suggest that Treg defects in ApoE(-/-) mice might partially be attributed to the disruption of TSLP-TSLPR-LAP signaling in epithelial cells (ECs) and DCs., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2015
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275. IL-17A contributes to brain ischemia reperfusion injury through calpain-TRPC6 pathway in mice.
- Author
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Zhang J, Mao X, Zhou T, Cheng X, and Lin Y
- Subjects
- Animals, Brain drug effects, Brain pathology, Brain Ischemia pathology, Calpain antagonists & inhibitors, Cysteine Proteinase Inhibitors pharmacology, Dipeptides pharmacology, Disease Models, Animal, Infarction, Middle Cerebral Artery, Interleukin-17 genetics, Male, Mice, Inbred C57BL, Mice, Knockout, Proteolysis, Recombinant Proteins metabolism, Reperfusion Injury pathology, TRPC6 Cation Channel, Time Factors, Brain physiopathology, Brain Ischemia physiopathology, Calpain metabolism, Interleukin-17 metabolism, Reperfusion Injury physiopathology, TRPC Cation Channels metabolism
- Abstract
Interleukin (IL)-17A plays an important role in the cerebral ischemia/reperfusion (I/R) injury. However, the mechanisms are still largely unknown. Calpain-transient receptor potential canonical (subtype) 6 (TRPC6) signaling pathway has been recently found to be implicated in brain I/R injury. However, their relationships with IL-17A remain unknown. This study aims to test whether this important signaling has correlation with IL-17A and how they led to the neuronal damage in I/R injury. In the present study, mice were subjected to middle cerebral artery occlusion (60 min) followed by reperfusion for different times. Infarct volumes and neurological deficits were examined. Real-time PCR (RT-PCR) and Western blotting were conducted to detect IL-17A expression in the penumbral brain tissue. Activation of calpain and expression of TRPC6 were also studied. We found that cerebral I/R significantly increased the levels of IL-17A at 1, 3 and 6 days after reperfusion in the penumbral area. IL-17A knockout or anti-IL-17A monoclonal antibody (mAb) significantly reduced whereas recombinant mouse-IL-17A (rIL-17A) increased the activation of calpain at 3 days after reperfusion. The calpain specific inhibitor calpeptin significantly increased TRPC6 expression. Brain injury and neurological deficits were largely abrogated by IL-17A knockout, anti-IL-17A mAb or calpeptin. Recombinant IL-17A treatment markedly increased I/R injury. In conclusion, IL-17A may promote brain I/R injury through the increase of calpain-mediated TRPC6 proteolysis. These results further outline a novel neuroprotective strategy with increased effectiveness for the inhibition of excess brain IL-17A in cerebral I/R injury., (Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2014
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276. Impairment of Circulating CD4⁺CD25⁺GARP⁺ regulatory T cells in patients with acute coronary syndrome.
- Author
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Meng K, Zhang W, Zhong Y, Mao X, Lin Y, Huang Y, Lang M, Peng Y, Zhu Z, Liu Y, Zhao X, Yu K, Wu B, Ji Q, and Zeng Q
- Subjects
- Acute Coronary Syndrome blood, Acute Coronary Syndrome pathology, Aged, Female, Forkhead Transcription Factors blood, Forkhead Transcription Factors immunology, Gene Expression Regulation immunology, Humans, Interleukin-2 Receptor alpha Subunit blood, Interleukin-2 Receptor alpha Subunit immunology, Male, Membrane Proteins blood, Middle Aged, T-Lymphocytes, Regulatory metabolism, T-Lymphocytes, Regulatory pathology, Acute Coronary Syndrome immunology, Membrane Proteins immunology, T-Lymphocytes, Regulatory immunology
- Abstract
Background: Atherosclerosis (AS) is an inflammatory and immune disease. Regulatory T cells (Tregs) suppress the activation of T cells and have been shown to play a protective role during the pathogenesis of AS. However, specific markers for Tregs are lacking. Recently, glycoprotein A repetitions predominant (GARP) was discovered as a specific marker of activated Tregs, and we therefore utilized GARP as a specific surface marker for Tregs in the current study., Methods: To assess whether GARP(+) Tregs are downregulated in patients with acute coronary syndrome (ACS), we examined CD4(+)CD25(+)GARP(+) T cell frequencies as well as their associated cytokines and suppressive function. Additionally, we compared GARP expression to that of FOXP3, which may be more sensitive as a marker of activated Tregs in patients with ACS., Results: Patients with ACS demonstrated a significant decrease in circulating CD4(+)CD25(+)GARP(+) Tregs. Moreover, the suppressive function of Tregs and levels of related cytokines were also impaired in ACS patients compared to those with stable angina (SA) or normal coronary artery (NCA). Additionally, after TCR stimulation, peripheral blood mononuclear cells (PBMCs) from patients with ACS exhibited a decrease in CD4(+)CD25(+)GARP(+) Tregs., Conclusions: These fnding indicate that circulating CD4(+)CD25(+)GARP(+) Tregs are impaired in patients withACS. Thus, targeting GARP may promote the protective function of Tregs in ACS., (© 2014 S. Karger AG, Basel.)
- Published
- 2014
- Full Text
- View/download PDF
277. Thymic stromal lymphopoietin attenuates the development of atherosclerosis in ApoE-/- mice.
- Author
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Yu K, Zhu P, Dong Q, Zhong Y, Zhu Z, Lin Y, Huang Y, Meng K, Ji Q, Yi G, Zhang W, Wu B, Mao Y, Cheng P, Zhao X, Mao X, and Zeng Q
- Subjects
- Animals, Apolipoproteins E deficiency, Apolipoproteins E genetics, Atherosclerosis prevention & control, Cells, Cultured, Cytokines therapeutic use, Mice, Mice, Inbred C57BL, T-Lymphocytes, Regulatory physiology, Th2 Cells physiology, Transforming Growth Factor beta physiology, Thymic Stromal Lymphopoietin, Atherosclerosis etiology, Cytokines physiology
- Abstract
Background: Thymic stromal lymphopoietin (TSLP) is a cytokine with multiple effects on the body. For one thing, TSLP induces Th2 immunoreaction and facilitates allergic reaction; for another, it promotes the differentiation of naturally occurring CD4+CD25+Foxp3+ regulatory T cells (nTregs) and maintains immune tolerance. However, the exact role of TSLP in atherosclerosis remains unknown., Methods and Results: In vitro, we examined the phenotype of TSLP-conditioned bone marrow dendritic cells (TSLP-DCs) of apolipoprotein E-deficient (ApoE-/-) mice and their capacity to induce the differentiation of Tregs. Our results indicated that TSLP-DCs obtained the characteristics of tolerogenic dendritic cells and increased a generation of CD4+ latency-associated peptide (LAP)+ Tregs and nTregs when cocultured with naive T cells. In addition, the functional relevance of TSLP and TSLP-DCs in the development of atherosclerosis was also determined. Interestingly, we found that TSLP was almost absent in cardiovascular tissue of ApoE-/- mice, and TSLP administration increased the levels of antioxidized low-density lipoprotein IgM and IgG1, but decreased the levels of IgG2a in plasma. Furthermore, mice treated with TSLP and TSLP-DCs developed significantly fewer (32.6% and 28.2%, respectively) atherosclerotic plaques in the aortic root compared with controls, along with increased numbers of CD4+LAP+ Tregs and nTregs in the spleen and decreased inflammation in the aorta, which could be abrogated by anti-TGF-β antibody., Conclusions: Our results revealed a protective role for TSLP in atherosclerosis that is possibly mediated by reestablishing a tolerogenic immune response, which may represent a novel possibility for treatment or prevention of atherosclerosis.
- Published
- 2013
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278. The effect of graphene oxide on conformation change, aggregation and cytotoxicity of HIV-1 regulatory protein (Vpr).
- Author
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Zhang M, Mao X, Wang C, Zeng W, Zhang C, Li Z, Fang Y, Yang Y, Liang W, and Wang C
- Subjects
- Dimerization, Oxides chemistry, Oxides toxicity, Protein Conformation, Cell Survival drug effects, Graphite chemistry, Graphite toxicity, Nanocapsules chemistry, Nanocapsules toxicity, vpr Gene Products, Human Immunodeficiency Virus toxicity
- Abstract
The fragment of viral protein R (Vpr), Vpr13-33, plays an important role in regulating nuclear importing of HIV through ion channel formation with a leucine-zipper-like α-helical conformation. Herein we report an approach to reduce cytotoxicity of Vpr13-33 by graphene oxide induced conformation change and aggregation. Preferential adsorption of Vpr13-33 on graphene oxide accompanied by conformation change from α-helix to β-sheet structures has been observed by using atomic force microscopy (AFM) and circular dichroism (CD). The submolecular structures of the Vpr13-33 peptide assembly on graphite surface have been identified by using scanning tunneling microscopy (STM), which confirms the β-sheet structures of Vpr13-33 on graphene oxide surface. The reduced cytotoxicity of Vpr13-33 to neuroblastoma cells and T cells are detected by MTT assay, which could be associated with the conformation change and stimulated aggregation of Vpr13-33 upon addition of graphene oxide through hydrophobic interaction. Furthermore, fluorescent leakage assay by using large unilamellar vesicles (LUVs) indicated that the GO reduced Vpr13-33-induced cytotoxicity could be associated with the inhibited "pore forming" function of Vpr13-33 by conformation change and aggregation., (Copyright © 2012 Elsevier Ltd. All rights reserved.)
- Published
- 2013
- Full Text
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279. [Bionic model for coordinated head-eye motion control].
- Author
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Mao X and Chen T
- Subjects
- Bionics, Fixation, Ocular physiology, Humans, Orientation, Photic Stimulation, Saccades physiology, Eye Movements physiology, Head Movements physiology, Ocular Physiological Phenomena, Reflex, Vestibulo-Ocular physiology
- Abstract
The relationships between eye movements and head movements of the primate during gaze shifts are analyzed in detail in the present paper. Applying the mechanisms of neurophysiology to engineering domain, we have improved the robot eye-head coordination. A bionic control strategy of coordinated head-eye motion was proposed. The processes of gaze shifts are composed of an initial fast phase followed by a slow phase. In the fast phase saccade eye movements and slow head movements were combined, which cooperate to bring gaze from an initial resting position toward the new target rapidly, while in the slow phase the gaze stability and target fixation were ensured by the action of the vestibulo-ocular reflex (VOR) where the eyes and head rotate by equal amplitudes in opposite directions. A bionic gaze control model was given. The simulation results confirmed the effectiveness of the model by comparing with the results of neurophysiology experiments.
- Published
- 2011
280. Structural characteristics of the beta-sheet-like human and rat islet amyloid polypeptides as determined by scanning tunneling microscopy.
- Author
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Mao X, Ma X, Liu L, Niu L, Yang Y, and Wang C
- Subjects
- Animals, Graphite chemistry, Humans, Islet Amyloid Polypeptide, Microscopy, Atomic Force, Microscopy, Scanning Tunneling, Protein Structure, Secondary, Rats, Amyloid chemistry
- Abstract
We demonstrate in this work that scanning tunneling microscopy (STM) provides a useful approach to obtaining structural information about human islet amyloid polypeptide (hIAPP) and rat islet amyloid polypeptide (rIAPP) assembly on highly oriented pyrolytic graphite (HOPG) with sub-molecular resolution. The observed hIAPP and rIAPP lamellae consisted of parallel stripes. The STM images of hIAPPs show multiple molecular folding structures, with an average of 11 amino acid residues for the core regions. In addition, the STM images also reveal the assembly characteristics of rIAPP lamellae and may indicate a secondary structural conformation from random coil to beta-sheet-like on the graphite surface.
- Published
- 2009
- Full Text
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281. Amyloid beta (1-42) folding multiplicity and single-molecule binding behavior studied with STM.
- Author
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Ma X, Liu L, Mao X, Niu L, Deng K, Wu W, Li Y, Yang Y, and Wang C
- Subjects
- Amyloid beta-Peptides metabolism, Benzothiazoles, Coloring Agents chemistry, Coloring Agents metabolism, Congo Red chemistry, Congo Red metabolism, Fluorescent Dyes chemistry, Fluorescent Dyes metabolism, Molecular Structure, Peptide Fragments metabolism, Protein Binding, Protein Folding, Thiazoles chemistry, Thiazoles metabolism, Amyloid beta-Peptides chemistry, Amyloid beta-Peptides ultrastructure, Microscopy, Scanning Tunneling, Peptide Fragments chemistry, Peptide Fragments ultrastructure, Protein Conformation
- Abstract
The fine folding and assembling characteristics of amyloid beta (Abeta) peptides are important to pharmaceutical studies of drug molecules and to the pathological analysis of neurodegenerative disorders such as Alzheimer's disease at the molecular level. Here we present observations of the multiple folding characteristics of amyloid peptide Abeta(42) lamellae using scanning tunneling microscopy. Molecularly resolved core regions of Abeta(42) hairpins and unfolded peptide assembly structures are identified. The parallel assembling characteristics of Abeta(42) hairpins can be confirmed in the study. In addition, single-molecule binding characteristics of Congo red and thioflavin T have been shown to bind at the groove regions of peptide assemblies. This study demonstrates a complementary venue for studying molecular heterogeneity of peptide assemblies, as well as the binding characteristics of molecular modulators.
- Published
- 2009
- Full Text
- View/download PDF
282. Effects of leptin on expression of acyl-coenzymea: cholesterol acyltransferases-1 in cultured human monocyte-macrophages.
- Author
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Bai Z, Cheng B, Yu Q, Li C, He P, and Mao X
- Subjects
- Atherosclerosis enzymology, Cell Differentiation, Cells, Cultured, Humans, Macrophages cytology, Monocytes cytology, Sterol O-Acyltransferase genetics, Tetradecanoylphorbol Acetate, Leptin pharmacology, Macrophages enzymology, Monocytes enzymology, Sterol O-Acyltransferase biosynthesis
- Abstract
To investigate the effects of leptin on expression of acyl-coenzymeA: cholesterol acyl-transferases-1 (ACAT-1) in monocyte-macrophage differentiation, human monocytic cells (THP-1) were cultured in RPMI 1640 and made to differentiate into macrophages under the incubation with phorbol myristate acetate (PMA) for 48 h. The cells were divided into 4 groups according to different intervention factors as follows: MCs cultured in RPM11640 medium with 10% FBS for 48 h served as MC group (control group), MCs cultured in medium with serum-free RPM11640 containing 5% BSA, 100 nmol/L PMA for 48 h as MP group, MCs cultured in RPMI1640 medium with 10% FBS, 10 micromol/ml leptin for 48 h as leptin-MC group, and MCs cultured in medium with serum-free RPMI1640 containing 5% BSA. 100 nmol/L PMA, and 10 micromol/ml leptin for 48 h as leptin-MP group. Immunocytochemistry, reverse transcription polymerase chain reaction (RT-PCR) and Western blot were performed, respectively, to observe the effects of leptin on expression of ACAT-1 in the monocyte-macrophage differentiation. Our results showed that expression of ACAT-1 protein and mRNA in MP-group is two times that in MC-group (P<0.05), and the expression of ACAT-1 protein and mRNA increased by up to 4 folds in leptin-MP group-as compared with that of MC group (P<0.01). Thus, our results support the idea that expression of ACAT-1 increases more in cultured human macrophages than in monocytes, and leptin can significantly promote ACAT-1 expression. It was concluded that high expression of ACAT-1 may accelerate the development of human atherogenesis, and leptin might participate in atherogenesis by increasing expression of ACAT-1.
- Published
- 2004
- Full Text
- View/download PDF
283. Angiogenic potency of bone marrow stromal cells improved by ex vivo hypoxia prestimulation.
- Author
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Mao X, Zeng Q, Wang X, Cao L, and Bai Z
- Subjects
- Animals, Bone Marrow Cells metabolism, Cell Hypoxia, Cells, Cultured, Coronary Circulation, Myocardial Infarction metabolism, Myocardial Infarction physiopathology, Neovascularization, Physiologic, Random Allocation, Rats, Rats, Wistar, Stromal Cells cytology, Vascular Endothelial Growth Factors genetics, Bone Marrow Cells cytology, Bone Marrow Transplantation, Myocardial Infarction surgery, Vascular Endothelial Growth Factors biosynthesis
- Abstract
To study the angiogenic potency of hypoxia-prestimulated bone marrow stromal cells (BMSCs) when transplanted into acute myocardial infarction models of rats. BMSCs were cultured under hypoxia condition for 24 h. Their expression of VEGF was investigated. The rat acute myocardial infarction models were made by coronary artery ligation and divided into 3 groups at random. In normoxia group, twice-passaged BMSCs were labeled with Bromodeoxyuridine (BrdU) and then implanted into the infarction regions and ischemic border of the recipients in 4 weeks. The rats in hypoxia group were implanted with hypoxia-prestimulated BMSCs. In control group, the model rats received only DMEM medium injection. Six-weeks after AMI, the infarction regions were examined to identify the angiogenesis and the expression of the VEGF. Our results showed that viable cells labeled with BrdU could be identified in the host hearts. The infarction regions in normoxia and hypoxia groups had a greater capillary density and increased VEGF expression than the regions in control group. The capillary density and VEGF expression in hypoxia group were higher than in normoxia group. It is concluded that the enhanced expression of VEGF in BMSCs could be induced by ex vivo hypoxia stimulation. BMSCs implantation promoted the angiogenesis in myocardial infarction tissue via supplying exogenic VEGF. Angiogenic potency of bone marrow stromal cells was improved by ex vivo hypoxia prestimulation though the enhanced VEGF expression.
- Published
- 2004
- Full Text
- View/download PDF
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