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Kumar G, Zhou Z, Wang Z, Kwan KM, Tin C, Ma CHE. Real-time field-programmable gate array-based closed-loop deep brain stimulation platform targeting cerebellar circuitry rescues motor deficits in a mouse model of cerebellar ataxia. CNS Neurosci Ther 2024; 30:e14638. [PMID: 38488445 PMCID: PMC10941591 DOI: 10.1111/cns.14638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 01/09/2024] [Accepted: 02/01/2024] [Indexed: 03/18/2024] Open
Abstract
AIMS The open-loop nature of conventional deep brain stimulation (DBS) produces continuous and excessive stimulation to patients which contributes largely to increased prevalence of adverse side effects. Cerebellar ataxia is characterized by abnormal Purkinje cells (PCs) dendritic arborization, loss of PCs and motor coordination, and muscle weakness with no effective treatment. We aim to develop a real-time field-programmable gate array (FPGA) prototype targeting the deep cerebellar nuclei (DCN) to close the loop for ataxia using conditional double knockout mice with deletion of PC-specific LIM homeobox (Lhx)1 and Lhx5, resulting in abnormal dendritic arborization and motor deficits. METHODS We implanted multielectrode array in the DCN and muscles of ataxia mice. The beneficial effect of open-loop DCN-DBS or closed-loop DCN-DBS was compared by motor behavioral assessments, electromyography (EMG), and neural activities (neurospike and electroencephalogram) in freely moving mice. FPGA board, which performed complex real-time computation, was used for closed-loop DCN-DBS system. RESULTS Closed-loop DCN-DBS was triggered only when symptomatic muscle EMG was detected in a real-time manner, which restored motor activities, electroencephalogram activities and neurospike properties completely in ataxia mice. Closed-loop DCN-DBS was more effective than an open-loop paradigm as it reduced the frequency of DBS. CONCLUSION Our real-time FPGA-based DCN-DBS system could be a potential clinical strategy for alleviating cerebellar ataxia and other movement disorders.
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Affiliation(s)
- Gajendra Kumar
- Department of NeuroscienceCity University of Hong KongHong KongHong Kong SAR
| | - Zhanhong Zhou
- Department of Biomedical EngineeringCity University of Hong KongHong KongHong Kong SAR
| | - Zhihua Wang
- Department of Biomedical EngineeringCity University of Hong KongHong KongHong Kong SAR
| | - Kin Ming Kwan
- School of Life Sciences, Center for Cell and Developmental Biology and State Key Laboratory of AgrobiotechnologyThe Chinese University of Hong KongHong KongHong Kong SAR
| | - Chung Tin
- Department of Biomedical EngineeringCity University of Hong KongHong KongHong Kong SAR
| | - Chi Him Eddie Ma
- Department of NeuroscienceCity University of Hong KongHong KongHong Kong SAR
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2
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Zhou Z, Yip HM, Tsimring K, Sur M, Ip JPK, Tin C. Effective and efficient neural networks for spike inference from in vivo calcium imaging. Cell Rep Methods 2023; 3:100462. [PMID: 37323579 PMCID: PMC10261900 DOI: 10.1016/j.crmeth.2023.100462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 02/21/2023] [Accepted: 03/31/2023] [Indexed: 06/17/2023]
Abstract
Calcium imaging provides advantages in monitoring large populations of neuronal activities simultaneously. However, it lacks the signal quality provided by neural spike recording in traditional electrophysiology. To address this issue, we developed a supervised data-driven approach to extract spike information from calcium signals. We propose the ENS2 (effective and efficient neural networks for spike inference from calcium signals) system for spike-rate and spike-event predictions using ΔF/F0 calcium inputs based on a U-Net deep neural network. When testing on a large, ground-truth public database, it consistently outperformed state-of-the-art algorithms in both spike-rate and spike-event predictions with reduced computational load. We further demonstrated that ENS2 can be applied to analyses of orientation selectivity in primary visual cortex neurons. We conclude that it would be a versatile inference system that may benefit diverse neuroscience studies.
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Affiliation(s)
- Zhanhong Zhou
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong SAR, China
| | - Hei Matthew Yip
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Katya Tsimring
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Mriganka Sur
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Jacque Pak Kan Ip
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Chung Tin
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong SAR, China
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Xiao N, Wu G, Zhou Z, Yao J, Wu B, Sui J, Tin C. Positive feedback of efferent copy via pontine nucleus facilitates cerebellum-mediated associative learning. Cell Rep 2023; 42:112072. [PMID: 36735531 DOI: 10.1016/j.celrep.2023.112072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 12/07/2022] [Accepted: 01/19/2023] [Indexed: 02/04/2023] Open
Abstract
The cerebellum is critical for motor coordination and learning. However, the role of feedback circuitry in this brain region has not been fully explored. Here, we characterize a nucleo-ponto-cortical feedback pathway in classical delayed eyeblink conditioning (dEBC) of rats. We find that the efference copy is conveyed from the interposed cerebellar nucleus (Int) to cerebellar cortex through pontine nucleus (PN). Inhibiting or exciting the projection from the Int to the PN can decelerate or speed up acquisition of dEBC, respectively. Importantly, we identify two subpopulations of PN neurons (PN1 and PN2) that convey and integrate the feedback signals with feedforward sensory signals. We also show that the feedforward and feedback pathways via different types of PN neurons contribute to the plastic changes and cooperate synergistically to the learning of dEBC. Our results suggest that this excitatory nucleo-ponto-cortical feedback plays a significant role in modulating associative motor learning in cerebellum.
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Affiliation(s)
- Na Xiao
- Department of Biomedical Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong; Advanced Biomedical Instrumentation Centre, Shatin, N.T., Hong Kong; Department of Mechanical Engineering, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Guangyan Wu
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China; Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Zhanhong Zhou
- Department of Biomedical Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Juan Yao
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China; Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Bing Wu
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China; Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Jianfeng Sui
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China; Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China.
| | - Chung Tin
- Department of Biomedical Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong.
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Cui C, Lau CH, Chu LT, Kwong HK, Tin C, Chen TH. Multimodal detection of flap endonuclease 1 activity through CRISPR/Cas12a trans-cleavage of single-strand DNA oligonucleotides. Biosens Bioelectron 2022; 220:114859. [DOI: 10.1016/j.bios.2022.114859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 10/05/2022] [Accepted: 10/23/2022] [Indexed: 11/29/2022]
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Lau CH, Huang S, Lam RHW, Tin C. PAM-flexible dual base editor-mediated random mutagenesis and self-activation strategies to improve CRISPRa potency. Mol Ther Methods Clin Dev 2022; 26:26-37. [PMID: 35755943 PMCID: PMC9198377 DOI: 10.1016/j.omtm.2022.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 05/25/2022] [Indexed: 12/01/2022]
Abstract
VP64 is the smallest transactivation domain that can be packaged together with the sgRNA into a single adeno-associated virus (AAV) vector. However, VP64-based CRISPRa often exerts modest activation to the target gene when only one sgRNA is used. Herein, we used PAM-flexible dual base editor-mediated mutagenesis and self-activation strategies to derive VP64 variants with gain-of-function mutations. First, we generated an HEK293FT transgenic clone to stably expressing pTK-CRISPRa-GFP. The sgRNA of CRISPRa was designed to target the TK promoter, thereby allowing self-activation of CRISPRa-GFP. Base editors were then used to randomly mutagenesis VP64 in this transgenic cell. VP64 with enhanced potency would translate into increment of GFP fluorescence intensity, thereby allowing positive selection of the desired VP64 mutants. This strategy has enabled us to identify several VP64 variants that are more potent than the wild-type VP64. ΔCRISPRa derived from these VP64 variants also efficiently activated the endogenous promoter of anti-aging and longevity genes (KLOTHO, SIRT6, and NFE2L2) in human cells. Since the overall size of these ΔCRISPRa transgenes is not increased, it remains feasible for all-in-one AAV applications. The strategies described here can facilitate high-throughput screening of the desired protein variants and adapted to evolve any other effector domains.
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Affiliation(s)
- Cia-Hin Lau
- Department of Biomedical Engineering, City University of Hong Kong, Room P6416, Yeung Kin Man Academic Building, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong, SAR, China
| | - Siping Huang
- Department of Biomedical Engineering, City University of Hong Kong, Room P6416, Yeung Kin Man Academic Building, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong, SAR, China
| | - Raymond H W Lam
- Department of Biomedical Engineering, City University of Hong Kong, Room P6416, Yeung Kin Man Academic Building, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong, SAR, China
| | - Chung Tin
- Department of Biomedical Engineering, City University of Hong Kong, Room P6416, Yeung Kin Man Academic Building, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong, SAR, China
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Jiang S, Wang YS, Zheng XX, Zhao SL, Wang Y, Sun L, Chen PH, Zhou Y, Tin C, Li HL, Sui JF, Wu GY. Itch-specific neurons in the ventrolateral orbital cortex selectively modulate the itch processing. Sci Adv 2022; 8:eabn4408. [PMID: 35905177 PMCID: PMC9337765 DOI: 10.1126/sciadv.abn4408] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 06/16/2022] [Indexed: 05/31/2023]
Abstract
Itch is a cutaneous sensation that is critical in driving scratching behavior. The long-standing question of whether there are specific neurons for itch modulation inside the brain remains unanswered. Here, we report a subpopulation of itch-specific neurons in the ventrolateral orbital cortex (VLO) that is distinct from the pain-related neurons. Using a Tet-Off cellular labeling system, we showed that local inhibition or activation of these itch-specific neurons in the VLO significantly suppressed or enhanced itch-induced scratching, respectively, whereas the intervention did not significantly affect pain. Conversely, suppression or activation of pain-specific neurons in the VLO significantly affected pain but not itch. Moreover, fiber photometry and immunofluorescence verified that these itch- and pain-specific neurons are distinct in their functional activity and histological location. In addition, the downstream targets of itch- and pain-specific neurons were different. Together, the present study uncovers an important subpopulation of neurons in the VLO that specifically modulates itch processing.
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Affiliation(s)
- Shan Jiang
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Yi-Song Wang
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Xiao-Xia Zheng
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Shan-Lan Zhao
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Yi Wang
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Lin Sun
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Peng-Hui Chen
- Department of Neurobiology, Army Medical University, Chongqing 400038, China
| | - Yi Zhou
- Department of Neurobiology, Army Medical University, Chongqing 400038, China
| | - Chung Tin
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong, SAR, People’s Republic of China
| | - Hong-Li Li
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Jian-Feng Sui
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
- Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Guang-Yan Wu
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
- Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
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Kumar G, Asthana P, Yung WH, Kwan KM, Tin C, Ma CHE. Deep Brain Stimulation of the Interposed Nucleus Reverses Motor Deficits and Stimulates Production of Anti-inflammatory Cytokines in Ataxia Mice. Mol Neurobiol 2022; 59:4578-4592. [PMID: 35581519 DOI: 10.1007/s12035-022-02872-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 05/05/2022] [Indexed: 11/24/2022]
Abstract
Cerebellum is one of the major targets of autoimmunity and cerebellar damage that leads to ataxia characterized by the loss of fine motor coordination and balance, with no treatment available. Deep brain stimulation (DBS) could be a promising treatment for ataxia but has not been extensively investigated. Here, our study aims to investigate the use of interposed nucleus of deep cerebellar nuclei (IN-DCN) for ataxia. We first characterized ataxia-related motor symptom of a Purkinje cell (PC)-specific LIM homeobox (Lhx)1 and Lhx5 conditional double knockout mice by motor coordination tests, and spontaneous electromyogram (EMG) recording. To validate IN-DCN as a target for DBS, in vivo local field potential (LFP) multielectrode array recording of IN-DCN revealed abnormal LFP amplitude surges in PCs. By synchronizing the EMG and IN-DCN recordings (neurospike and LFP) with high-speed video recordings, ataxia mice showed poorly coordinated movements associated with low EMG amplitude and aberrant IN-DCN neural firing. To optimize IN-DCN-DBS for ataxia, we tested DBS parameters from low (30 Hz) to high stimulation frequency (130 or 150 Hz), and systematically varied pulse width values (60 or 80 µs) to maximize motor symptom control in ataxia mice. The optimal IN-DCN-DBS parameter reversed motor deficits in ataxia mice as detected by animal behavioral tests and EMG recording. Mechanistically, cytokine array analysis revealed that anti-inflammatory cytokines such as interleukin (IL)-13 and IL-4 were upregulated after IN-DCN-DBS, which play key roles in neural excitability. As such, we show that IN-DCN-DBS is a promising treatment for ataxia and possibly other movement disorders alike.
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Affiliation(s)
- Gajendra Kumar
- Department of Neuroscience, City University of Hong Kong, Tat Chee Avenue, Hong Kong SAR, China
| | - Pallavi Asthana
- Department of Neuroscience, City University of Hong Kong, Tat Chee Avenue, Hong Kong SAR, China
| | - Wing Ho Yung
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR, China
| | - Kin Ming Kwan
- School of Life Sciences, Center for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR, China
| | - Chung Tin
- Department of Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Hong Kong, SAR, China
| | - Chi Him Eddie Ma
- Department of Neuroscience, City University of Hong Kong, Tat Chee Avenue, Hong Kong SAR, China.
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Wang F, Liu LS, Li P, Lau CH, Leung HM, Chin YR, Tin C, Lo PK. Cellular uptake, tissue penetration, biodistribution, and biosafety of threose nucleic acids: Assessing in vitro and in vivo delivery. Mater Today Bio 2022; 15:100299. [PMID: 35637854 PMCID: PMC9142632 DOI: 10.1016/j.mtbio.2022.100299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/03/2022] [Accepted: 05/16/2022] [Indexed: 11/28/2022]
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Leung HM, Lau CH, Ho JWT, Chan MS, Chang TJH, Law LH, Wang F, Tam DY, Liu LS, Chan KWY, Tin C, Lo PK. Targeted brain tumor imaging by using discrete biopolymer-coated nanodiamonds across the blood-brain barrier. Nanoscale 2021; 13:3184-3193. [PMID: 33527933 DOI: 10.1039/d0nr06765b] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Short circulation lifetime, poor blood-brain barrier (BBB) permeability and low targeting specificity limit nanovehicles from crossing the vascular barrier and reaching the tumor site. Consequently, the precise diagnosis of malignant brain tumors remains a great challenge. This study demonstrates the imaging of photostable biopolymer-coated nanodiamonds (NDs) with tumor targeting properties inside the brain. NDs are labeled with PEGylated denatured bovine serum albumin (BSA) and tumor vasculature targeting tripeptides RGD. The modified NDs show high colloidal stability in different buffer systems. Moreover, it is found that discrete dcBSA-PEG-NDs cross the in vitro BBB model more effectively than aggregated NDs. Importantly, compared with the non-targeting NDs, RGD-dcBSA-PEG-NDs can selectively target the tumor site in U-87 MG bearing mice after systemic injection. Overall, this discrete ND system enables efficacious brain tumor visualization with minimal toxicity to other major organs, and is worthy of further investigation into the applications as a unique platform for noninvasive theragnostics and/or thermometry at different stages of human diseases in the brain.
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Affiliation(s)
- Hoi Man Leung
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China.
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10
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Abstract
The last few years have seen tremendous advances in CRISPR-mediated genome editing. Great efforts have been made to improve the efficiency, specificity, editing window, and targeting scope of CRISPR/Cas9-mediated transgene knock-in and gene correction. In this article, we comprehensively review recent progress in CRISPR-based strategies for targeted transgene knock-in and gene correction in both homology-dependent and homology-independent approaches. We cover homology-directed repair (HDR), synthesis-dependent strand annealing (SDSA), microhomology-mediated end joining (MMEJ), and homology-mediated end joining (HMEJ) pathways for a homology-dependent strategy and alternative DNA repair pathways such as non-homologous end joining (NHEJ), base excision repair (BER), and mismatch repair (MMR) for a homology-independent strategy. We also discuss base editing and prime editing that enable direct conversion of nucleotides in genomic DNA without damaging the DNA or requiring donor DNA. Notably, we illustrate the key mechanisms and design principles for each strategy, providing design guidelines for multiplex, flexible, scarless gene insertion and replacement at high efficiency and specificity. In addition, we highlight next-generation base editors that provide higher editing efficiency, fewer undesired by-products, and broader targeting scope.
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Affiliation(s)
- Cia-Hin Lau
- Department of Biomedical Engineering, Academic 1, 83 Tat Chee Avenue, City University of Hong Kong, Hong Kong
| | - Chung Tin
- Department of Biomedical Engineering, Academic 1, 83 Tat Chee Avenue, City University of Hong Kong, Hong Kong
| | - Yousin Suh
- Department of Obstetrics and Gynecology, Columbia University Irving Medical Center, 630 West 168th Street, New York, NY 10032, USA
- Department of Genetics and Development, Columbia University Irving Medical Center, 630 West 168th Street, New York, NY 10032, USA
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Abstract
Gene therapy and transgenic research have advanced quickly in recent years due to the development of CRISPR technology. The rapid development of CRISPR technology has been largely benefited by chemical engineering. Firstly, chemical or synthetic substance enables spatiotemporal and conditional control of Cas9 or dCas9 activities. It prevents the leaky expression of CRISPR components, as well as minimizes toxicity and off-target effects. Multi-input logic operations and complex genetic circuits can also be implemented via multiplexed and orthogonal regulation of target genes. Secondly, rational chemical modifications to the sgRNA enhance gene editing efficiency and specificity by improving sgRNA stability and binding affinity to on-target genomic loci, and hence reducing off-target mismatches and systemic immunogenicity. Chemically-modified Cas9 mRNA is also more active and less immunogenic than the native mRNA. Thirdly, nonviral vehicles can circumvent the challenges associated with viral packaging and production through the delivery of Cas9-sgRNA ribonucleoprotein complex or large Cas9 expression plasmids. Multi-functional nanovectors enhance genome editing in vivo by overcoming multiple physiological barriers, enabling ligand-targeted cellular uptake, and blood-brain barrier crossing. Chemical engineering can also facilitate viral-based delivery by improving vector internalization, allowing tissue-specific transgene expression, and preventing inactivation of the viral vectors in vivo. This review aims to discuss how chemical engineering has helped improve existing CRISPR applications and enable new technologies for biomedical research. The usefulness, advantages, and molecular action for each chemical engineering approach are also highlighted.
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Affiliation(s)
- Cia-Hin Lau
- Department of Biomedical Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Chung Tin
- Department of Biomedical Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong
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Tam DY, Ho JWT, Chan MS, Lau CH, Chang TJH, Leung HM, Liu LS, Wang F, Chan LLH, Tin C, Lo PK. Penetrating the Blood-Brain Barrier by Self-Assembled 3D DNA Nanocages as Drug Delivery Vehicles for Brain Cancer Therapy. ACS Appl Mater Interfaces 2020; 12:42447. [PMID: 32432847 DOI: 10.1021/acsami.0c14625] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The development of biocompatible drug delivery vehicles for cancer therapy in the brain remains a big challenge. In this study, we designed self-assembled DNA nanocages functionalized with or without blood-brain barrier (BBB)-targeting ligands, d and we investigated their penetration across the BBB. Our DNA nanocages were not cytotoxic and they were substantially taken up in brain capillary endothelial cells and Uppsala 87 malignant glioma (U-87 MG) cells. We found that ligand modification is not essential for this DNA system as the ligand-free DNA nanocages (LF-NCs) could still cross the BBB by endocytosis inin vitro and in vivo models. Our spherical DNA nanocages were more permeable across the BBB compared with tubular DNA nanotubes. Remarkably, in vivo studies revealed that DNA nanocages could carry anticancer drugs across the BBB and inhibit the tumor growth in a U-87 MG xenograft mouse model. This is the first example showing the potential of DNA nanocages as innovative delivery vehicles to the brain for cancer therapy. Unlike other delivery systems, our work suggest that a DNA nanocage-based platform provides a safe and cost-effective tool for targeted delivery to the brain and therapy for brain tumors.
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Affiliation(s)
- Dick Yan Tam
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Jonathan Weng-Thim Ho
- Department of Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Miu Shan Chan
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Cia Hin Lau
- Department of Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Tristan Juin Han Chang
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Hoi Man Leung
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Ling Sum Liu
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Fei Wang
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Leanne Lai Hang Chan
- Department of Electrical Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Chung Tin
- Department of Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Pik Kwan Lo
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
- Key Laboratory of Biochip Technology, Biotech and Health Centre, Shenzhen Research Institute of City University of Hong Kong, Shenzhen 518057, China
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Tam DY, Ho JWT, Chan MS, Lau CH, Chang TJH, Leung HM, Liu LS, Wang F, Chan LLH, Tin C, Lo PK. Penetrating the Blood-Brain Barrier by Self-Assembled 3D DNA Nanocages as Drug Delivery Vehicles for Brain Cancer Therapy. ACS Appl Mater Interfaces 2020; 12:28928-28940. [PMID: 32432847 DOI: 10.1021/acsami.0c02957] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The development of biocompatible drug delivery vehicles for cancer therapy in the brain remains a big challenge. In this study, we designed self-assembled DNA nanocages functionalized with or without blood-brain barrier (BBB)-targeting ligands, d and we investigated their penetration across the BBB. Our DNA nanocages were not cytotoxic and they were substantially taken up in brain capillary endothelial cells and Uppsala 87 malignant glioma (U-87 MG) cells. We found that ligand modification is not essential for this DNA system as the ligand-free DNA nanocages (LF-NCs) could still cross the BBB by endocytosis inin vitro and in vivo models. Our spherical DNA nanocages were more permeable across the BBB compared with tubular DNA nanotubes. Remarkably, in vivo studies revealed that DNA nanocages could carry anticancer drugs across the BBB and inhibit the tumor growth in a U-87 MG xenograft mouse model. This is the first example showing the potential of DNA nanocages as innovative delivery vehicles to the brain for cancer therapy. Unlike other delivery systems, our work suggest that a DNA nanocage-based platform provides a safe and cost-effective tool for targeted delivery to the brain and therapy for brain tumors.
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Affiliation(s)
- Dick Yan Tam
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Jonathan Weng-Thim Ho
- Department of Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Miu Shan Chan
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Cia Hin Lau
- Department of Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Tristan Juin Han Chang
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Hoi Man Leung
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Ling Sum Liu
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Fei Wang
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Leanne Lai Hang Chan
- Department of Electrical Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Chung Tin
- Department of Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Pik Kwan Lo
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
- Key Laboratory of Biochip Technology, Biotech and Health Centre, Shenzhen Research Institute of City University of Hong Kong, Shenzhen 518057, China
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14
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Wang F, Liu LS, Lau CH, Han Chang TJ, Tam DY, Leung HM, Tin C, Lo PK. Synthetic α-l-Threose Nucleic Acids Targeting BcL-2 Show Gene Silencing and in Vivo Antitumor Activity for Cancer Therapy. ACS Appl Mater Interfaces 2019; 11:38510-38518. [PMID: 31556592 DOI: 10.1021/acsami.9b14324] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We design and synthesize a sequence-defined α-l-threose nucleic acid (TNA) polymer, which is complementary to certain nucleotide sites of target anti-apoptotic proteins, BcL-2 involving in development and progression of tumors. Compared to scramble TNA, anti-BcL-2 TNA significantly suppresses target mRNA and protein expression in cancerous cells and shows antitumor activity in carcinoma xenografts, resulting in suppression of tumor cell growth and induction of tumor cell death. Together with good biocompatibility, very low toxicity, excellent specificity features, and strong binding affinity toward the complementary target RNAs, TNAs become new useful biomaterials and effective alternatives to traditional antisense oligonucleotides including locked nucleic acids, morpholino oligomers, and peptide nucleic acids in antisense therapy. Compared to conventional cancer therapy such as radiotherapy, surgery, and chemotherapy, we anticipate that this TNA-based polymeric system will work effectively in antisense cancer therapy and shortly start to play an important role in practical application.
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Affiliation(s)
| | | | | | | | | | | | | | - Pik Kwan Lo
- Key Laboratory of Biochip Technology, Biotech and Health Care , Shenzhen Research Institute of City University of Hong Kong , Shenzhen 518057 , China
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15
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Xu T, Xiao N, Zhai X, Kwan Chan P, Tin C. Real-time cerebellar neuroprosthetic system based on a spiking neural network model of motor learning. J Neural Eng 2019; 15:016021. [PMID: 29115280 DOI: 10.1088/1741-2552/aa98e9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Damage to the brain, as a result of various medical conditions, impacts the everyday life of patients and there is still no complete cure to neurological disorders. Neuroprostheses that can functionally replace the damaged neural circuit have recently emerged as a possible solution to these problems. Here we describe the development of a real-time cerebellar neuroprosthetic system to substitute neural function in cerebellar circuitry for learning delay eyeblink conditioning (DEC). APPROACH The system was empowered by a biologically realistic spiking neural network (SNN) model of the cerebellar neural circuit, which considers the neuronal population and anatomical connectivity of the network. The model simulated synaptic plasticity critical for learning DEC. This SNN model was carefully implemented on a field programmable gate array (FPGA) platform for real-time simulation. This hardware system was interfaced in in vivo experiments with anesthetized rats and it used neural spikes recorded online from the animal to learn and trigger conditioned eyeblink in the animal during training. MAIN RESULTS This rat-FPGA hybrid system was able to process neuronal spikes in real-time with an embedded cerebellum model of ~10 000 neurons and reproduce learning of DEC with different inter-stimulus intervals. Our results validated that the system performance is physiologically relevant at both the neural (firing pattern) and behavioral (eyeblink pattern) levels. SIGNIFICANCE This integrated system provides the sufficient computation power for mimicking the cerebellar circuit in real-time. The system interacts with the biological system naturally at the spike level and can be generalized for including other neural components (neuron types and plasticity) and neural functions for potential neuroprosthetic applications.
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Affiliation(s)
- Tao Xu
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong, SAR, People's Republic of China
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16
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Lau CH, Ho JWT, Lo PK, Tin C. Targeted Transgene Activation in the Brain Tissue by Systemic Delivery of Engineered AAV1 Expressing CRISPRa. Mol Ther Nucleic Acids 2019; 16:637-649. [PMID: 31108320 PMCID: PMC6526230 DOI: 10.1016/j.omtn.2019.04.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 04/14/2019] [Accepted: 04/14/2019] [Indexed: 01/10/2023]
Abstract
Targeted transcriptional modulation in the central nervous system (CNS) can be achieved by adeno-associated virus (AAV) delivery of CRISPR activation (CRISPRa) and interference (CRISPRi) transgenes. To enable AAV packaging, we constructed minimal CRISPRa and CRISPRi transgenes by fusing catalytically inactive Staphylococcus aureus Cas9 (dSaCas9) to the transcriptional activator (VP64 and VP160) and repressor (KRAB and SID4X) domains along with truncated regulatory elements. We then evaluated the performance of these constructs in two reporter assays (bioluminescent and fluorescent), five endogenous genes (Camk2a, Mycn, Nrf2, Keap1, and PDGFRA), and two cell lines (neuro-2a [N2a] and U87) by targeting the promoter and/or enhancer regions. To enable systemic delivery of AAVs to the CNS, we have also generated an AAV1-PHP.B by inserting a 7-mer PHP.B peptide on AAV1 capsid. We showed that AAV1-PHP.B can efficiently cross the blood-brain barrier (BBB) and be taken up by the brain tissue upon lateral tail vein injection in mice. Importantly, a single-dose intravenous administration of AAV1-PHP.B expressing CRISPRa was shown to achieve targeted transgene activation in the mouse brain. This proof-of-concept study will contribute to the development of a non-invasive, specific and potent AAV-CRISPR system for correcting transcriptional misregulation in broad brain areas and multiple neuroanatomical structures.
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Affiliation(s)
- Cia-Hin Lau
- Department of Biomedical Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Jonathan Weng-Thim Ho
- Department of Biomedical Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Pik Kwan Lo
- Department of Chemistry, City University of Hong Kong, Kowloon Tong, Hong Kong; CityU Shenzhen Research Institute, Shenzhen, China
| | - Chung Tin
- Department of Biomedical Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong; CityU Shenzhen Research Institute, Shenzhen, China.
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17
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Zhou Z, Zhai X, Tin C. A Cerebellar Spiking Neural Model for Phase Reversal of Vestibulo-ocular Reflex. Annu Int Conf IEEE Eng Med Biol Soc 2018; 2018:6121-6124. [PMID: 30441731 DOI: 10.1109/embc.2018.8513671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cerebellum possesses very rich motor control and learning capability which is critical for animals. In this study, we proposed a spiking neural network model of cerebellum for gain and phase adaptation in vestibulo-ocular reflex (VOR). VOR is a critical adaptive reflexive eye movement for maintaining a stable visual field. In this model (with neuron number at the order of 104), synaptic plasticity at parallel fiber-Purkinje cell synapses was considered. In particular, we have shown that the inhibitory inputs from molecular layer interneurons on Purkinje cells play a critical role in phase adaptation of VOR. The inhibitory input from interneurons indirectly affects the strength of long-term potentiation (LTP) and long-term depression (LTD), resulting in more drastic phase shift upon learning and hence allowing phase reversal of VOR. The strength of inhibitory input also affects the maximum phase shift that can be achieved. Our result is consistent with experiments in mutant mice with blocked inhibitory inputs.
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18
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Cui X, Liu Y, Hu D, Qian W, Tin C, Sun D, Chen W, Lam RHW. A fluorescent microbead-based microfluidic immunoassay chip for immune cell cytokine secretion quantification. Lab Chip 2018; 18:522-531. [PMID: 29326990 DOI: 10.1039/c7lc01183k] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Quantitative and dynamic analyses of immune cell secretory cytokines are essential for precise determination and characterization of the "immune phenotype" of patients for clinical diagnosis and treatment of immune-related diseases. Although multiple methods including the enzyme-linked immunosorbent assay (ELISA) have been applied for cytokine detection, such measurements remain very challenging in real-time, high-throughput, and high-sensitivity immune cell analysis. In this paper, we report a highly integrated microfluidic device that allows for on-chip isolation, culture, and stimulation, as well as sensitive and dynamic cytokine profiling of immune cells. Such a microfluidic sensing chip is integrated with cytometric fluorescent microbeads for real-time and multiplexed monitoring of immune cell cytokine secretion dynamics, consuming a relatively small extracted sample volume (160 nl) without interrupting the immune cell culture. Furthermore, it is integrated with a Taylor dispersion-based mixing unit in each detection chamber that shortens the immunoassay period down to less than 30 minutes. We demonstrate the profiling of multiple pro-inflammatory cytokine secretions (e.g. interleukin-6, interleukin-8, and tumor necrosis factors) of human peripheral blood mononuclear cells (PBMCs) with a sensitivity of 20 pg ml-1 and a sample volume of 160 nl per detection. Further applications of this automated, rapid, and high-throughput microfluidic immunophenotyping platform can help unleash the mechanisms of systemic immune responses, and enable efficient assessments of the pathologic immune status for clinical diagnosis and immune therapy.
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Affiliation(s)
- Xin Cui
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong.
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19
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Zhai X, Jelfs B, Chan RHM, Tin C. Self-Recalibrating Surface EMG Pattern Recognition for Neuroprosthesis Control Based on Convolutional Neural Network. Front Neurosci 2017; 11:379. [PMID: 28744189 PMCID: PMC5504564 DOI: 10.3389/fnins.2017.00379] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 06/19/2017] [Indexed: 11/21/2022] Open
Abstract
Hand movement classification based on surface electromyography (sEMG) pattern recognition is a promising approach for upper limb neuroprosthetic control. However, maintaining day-to-day performance is challenged by the non-stationary nature of sEMG in real-life operation. In this study, we propose a self-recalibrating classifier that can be automatically updated to maintain a stable performance over time without the need for user retraining. Our classifier is based on convolutional neural network (CNN) using short latency dimension-reduced sEMG spectrograms as inputs. The pretrained classifier is recalibrated routinely using a corrected version of the prediction results from recent testing sessions. Our proposed system was evaluated with the NinaPro database comprising of hand movement data of 40 intact and 11 amputee subjects. Our system was able to achieve ~10.18% (intact, 50 movement types) and ~2.99% (amputee, 10 movement types) increase in classification accuracy averaged over five testing sessions with respect to the unrecalibrated classifier. When compared with a support vector machine (SVM) classifier, our CNN-based system consistently showed higher absolute performance and larger improvement as well as more efficient training. These results suggest that the proposed system can be a useful tool to facilitate long-term adoption of prosthetics for amputees in real-life applications.
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Affiliation(s)
- Xiaolong Zhai
- Department of Mechanical and Biomedical Engineering, City University of Hong KongHong Kong, Hong Kong
| | - Beth Jelfs
- Department of Electronic Engineering, City University of Hong KongHong Kong, Hong Kong.,Centre for Biosystems, Neuroscience, and Nanotechnology, City University of Hong KongHong Kong, Hong Kong
| | - Rosa H M Chan
- Department of Electronic Engineering, City University of Hong KongHong Kong, Hong Kong.,Centre for Biosystems, Neuroscience, and Nanotechnology, City University of Hong KongHong Kong, Hong Kong
| | - Chung Tin
- Department of Mechanical and Biomedical Engineering, City University of Hong KongHong Kong, Hong Kong.,Centre for Biosystems, Neuroscience, and Nanotechnology, City University of Hong KongHong Kong, Hong Kong.,Centre for Robotics and Automation, City University of Hong KongHong Kong, Hong Kong
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20
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Luo J, Coapes G, Mak T, Yamazaki T, Tin C, Degenaar P. Real-Time Simulation of Passage-of-Time Encoding in Cerebellum Using a Scalable FPGA-Based System. IEEE Trans Biomed Circuits Syst 2016; 10:742-753. [PMID: 26452290 DOI: 10.1109/tbcas.2015.2460232] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The cerebellum plays a critical role for sensorimotor control and learning. However, dysmetria or delays in movements' onsets consequent to damages in cerebellum cannot be cured completely at the moment. Neuroprosthesis is an emerging technology that can potentially substitute such motor control module in the brain. A pre-requisite for this to become practical is the capability to simulate the cerebellum model in real-time, with low timing distortion for proper interfacing with the biological system. In this paper, we present a frame-based network-on-chip (NoC) hardware architecture for implementing a bio-realistic cerebellum model with ∼ 100 000 neurons, which has been used for studying timing control or passage-of-time (POT) encoding mediated by the cerebellum. The simulation results verify that our implementation reproduces the POT representation by the cerebellum properly. Furthermore, our field-programmable gate array (FPGA)-based system demonstrates excellent computational speed that it can complete 1sec real world activities within 25.6 ms. It is also highly scalable such that it can maintain approximately the same computational speed even if the neuron number increases by one order of magnitude. Our design is shown to outperform three alternative approaches previously used for implementing spiking neural network model. Finally, we show a hardware electronic setup and illustrate how the silicon cerebellum can be adapted as a potential neuroprosthetic platform for future biological or clinical application.
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21
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Au NPB, Kumar G, Asthana P, Tin C, Mak YL, Chan LL, Lam PKS, Ma CHE. Ciguatoxin reduces regenerative capacity of axotomized peripheral neurons and delays functional recovery in pre-exposed mice after peripheral nerve injury. Sci Rep 2016; 6:26809. [PMID: 27229176 PMCID: PMC4882531 DOI: 10.1038/srep26809] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 05/10/2016] [Indexed: 01/03/2023] Open
Abstract
Ciguatera fish poisoning (CFP) results from consumption of tropical reef fish containing ciguatoxins (CTXs). Pacific (P)-CTX-1 is among the most potent known CTXs and the predominant source of CFP in the endemic region responsible for the majority of neurological symptoms in patients. Chronic and persistent neurological symptoms occur in some CFP patients, which often result in incomplete functional recovery for years. However, the direct effects of exposure to CTXs remain largely unknown. In present study, we exposed mice to CTX purified from ciguatera fish sourced from the Pacific region. P-CTX-1 was detected in peripheral nerves within hours and persisted for two months after exposure. P-CTX-1 inhibited axonal regrowth from axotomized peripheral neurons in culture. P-CTX-1 exposure reduced motor function in mice within the first two weeks of exposure before returning to baseline levels. These pre-exposed animals exhibited delayed sensory and motor functional recovery, and irreversible motor deficits after peripheral nerve injury in which formation of functional synapses was impaired. These findings are consistent with reduced muscle function, as assessed by electromyography recordings. Our study provides strong evidence that the persistence of P-CTX-1 in peripheral nerves reduces the intrinsic growth capacity of peripheral neurons, resulting in delayed functional recovery after injury.
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Affiliation(s)
- Ngan Pan Bennett Au
- Department of Biomedical Sciences, City University of Hong Kong, Tat Chee Avenue, Hong Kong
| | - Gajendra Kumar
- Department of Biomedical Sciences, City University of Hong Kong, Tat Chee Avenue, Hong Kong
| | - Pallavi Asthana
- Department of Biomedical Sciences, City University of Hong Kong, Tat Chee Avenue, Hong Kong
| | - Chung Tin
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Hong Kong.,Centre for Biosystems, Neuroscience, and Nanotechnology, City University of Hong Kong, Tat Chee Avenue, Hong Kong
| | - Yim Ling Mak
- State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Hong Kong.,Shenzhen Key Laboratory for the Sustainable Use of Marine Biodiversity, Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
| | - Leo Lai Chan
- Department of Biomedical Sciences, City University of Hong Kong, Tat Chee Avenue, Hong Kong.,State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Hong Kong.,Shenzhen Key Laboratory for the Sustainable Use of Marine Biodiversity, Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
| | - Paul Kwan Sing Lam
- State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Hong Kong.,Shenzhen Key Laboratory for the Sustainable Use of Marine Biodiversity, Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen, China.,Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong
| | - Chi Him Eddie Ma
- Department of Biomedical Sciences, City University of Hong Kong, Tat Chee Avenue, Hong Kong.,Centre for Biosystems, Neuroscience, and Nanotechnology, City University of Hong Kong, Tat Chee Avenue, Hong Kong.,State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Hong Kong
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22
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Chan MS, Tam DY, Dai Z, Liu LS, Ho JWT, Chan ML, Xu D, Wong MS, Tin C, Lo PK. Mitochondrial Delivery of Therapeutic Agents by Amphiphilic DNA Nanocarriers. Small 2016; 12:770-81. [PMID: 26690974 DOI: 10.1002/smll.201503051] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 11/01/2015] [Indexed: 05/23/2023]
Abstract
The first example of mitochondrial delivery of the anticancer drug doxorubicin (Dox) is presented by lipid-functionalized DNA nanocages (LNCs). Dox localized in mitochondria induces significant cytotoxicity and cellular apoptosis in MCF-7 compared with Dox localized in lysosomes. These results suggest that LNC has the potential to be an outstanding tool in the treatment of specific organelle-related diseases such as cancers.
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Affiliation(s)
- Miu Shan Chan
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
- Key Laboratory of Biochip Technology, Biotech and Health Centre, Shenzhen Research Institute of City University of Hong Kong, Shenzhen, 518057, China
| | - Dick Yan Tam
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
- Key Laboratory of Biochip Technology, Biotech and Health Centre, Shenzhen Research Institute of City University of Hong Kong, Shenzhen, 518057, China
| | - Ziwen Dai
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
- Key Laboratory of Biochip Technology, Biotech and Health Centre, Shenzhen Research Institute of City University of Hong Kong, Shenzhen, 518057, China
| | - Ling Sum Liu
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
- Key Laboratory of Biochip Technology, Biotech and Health Centre, Shenzhen Research Institute of City University of Hong Kong, Shenzhen, 518057, China
| | - Jonathan Weng-Thim Ho
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Man Lee Chan
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Di Xu
- Department of Chemistry and Institute of Molecular Functional Materials, Hong Kong Baptist University, Kowloon Tong, Hong Kong, SAR, China
| | - Man Shing Wong
- Department of Chemistry and Institute of Molecular Functional Materials, Hong Kong Baptist University, Kowloon Tong, Hong Kong, SAR, China
| | - Chung Tin
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Pik Kwan Lo
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
- Key Laboratory of Biochip Technology, Biotech and Health Centre, Shenzhen Research Institute of City University of Hong Kong, Shenzhen, 518057, China
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23
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Tam DY, Dai Z, Chan MS, Liu LS, Cheung MC, Bolze F, Tin C, Lo PK. A Reversible DNA Logic Gate Platform Operated by One- and Two-Photon Excitations. Angew Chem Int Ed Engl 2015; 55:164-8. [DOI: 10.1002/anie.201507249] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 10/15/2015] [Indexed: 12/21/2022]
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24
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Tam DY, Dai Z, Chan MS, Liu LS, Cheung MC, Bolze F, Tin C, Lo PK. A Reversible DNA Logic Gate Platform Operated by One- and Two-Photon Excitations. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201507249] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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25
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Poon CS, Tin C, Song G. Submissive hypercapnia: Why COPD patients are more prone to CO2 retention than heart failure patients. Respir Physiol Neurobiol 2015; 216:86-93. [PMID: 25891787 DOI: 10.1016/j.resp.2015.03.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 02/16/2015] [Accepted: 03/02/2015] [Indexed: 01/08/2023]
Abstract
Patients with late-stage chronic obstructive pulmonary disease (COPD) are prone to CO2 retention, a condition which has been often attributed to increased ventilation-perfusion mismatch particularly during oxygen therapy. However, patients with mild-to-moderate COPD or chronic heart failure (CHF) also suffer similar ventilatory inefficiency but they remain near-normocapnic at rest and during exercise with an augmented respiratory effort to compensate for the wasted dead space ventilation. In severe COPD, the augmented exercise ventilation progressively reverses as the disease advances, resulting in hypercapnia at peak exercise as ventilatory limitation due to increasing expiratory flow limitation and dynamic lung hyperinflation sets in. Submissive hypercapnia is an emerging paradigm for understanding optimal ventilatory control and cost/benefit decision-making under prohibitive respiratory chemical-mechanical constraints, where the need to maintain normocapnia gives way to the mounting need to conserve the work of breathing. In severe/very severe COPD, submissive hypercapnia epitomizes the respiratory controller's 'can't breathe, so won't breathe' say-uncle policy when faced with insurmountable ventilatory limitation. Even in health, submissive hypercapnia ensues during CO2 breathing/rebreathing when the inhaled CO2 renders normocapnia difficult to restore even with maximal respiratory effort, hence the respiratory controller's 'ain't fresh, so won't breathe' modus operandi. This 'wisdom of the body' with a principled decision to tolerate hypercapnia when faced with prohibitive ventilatory or gas exchange limitations rather than striving for untenable normocapnia at all costs is analogous to the notion of permissive hypercapnia in critical care, a clinical strategy to minimize the risks of ventilator-induced lung injury in patients receiving mechanical ventilation.
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Affiliation(s)
- Chi-Sang Poon
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Bldg E25-250, 77 Massachusetts Avenue, Cambridge, MA 02139, United States.
| | - Chung Tin
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Bldg E25-250, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Department of Mechanical and Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, China
| | - Gang Song
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Bldg E25-250, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
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26
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Luo J, Coapes G, Mak T, Yamazaki T, Tin C, Degenaar P. A scalable FPGA-based cerebellum for passage-of-time representation. Annu Int Conf IEEE Eng Med Biol Soc 2015; 2014:3102-5. [PMID: 25570647 DOI: 10.1109/embc.2014.6944279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The cerebellum plays a critical role for sensorimotor control and learning. However dysmertria or delays in movements' onsets consequent to damages in cerebellum cannot be cured completely at the moment. To foster a potential cure based on neuroprosthetic technology, we present a frame-based Network-on-Chip (NoC) hardware architecture for implementing a bio-realistic cerebellum model with 100,000 neurons, which has been used for studying timing control or passage-of-time (POT) encoding mediated by the cerebellum. The results demonstrate that our implementation can reproduce the POT functionality properly. The computational speed can achieve to 25.6 ms for simulating 1 sec real world activities. Furthermore, we show a hardware electronic setup and illustrate how the silicon cerebellum can be adapted as a potential neuroprosthetic platform for future biological or clinical applications.
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27
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Jelfs B, Zhou S, Wong BKY, Tin C, Chan RHM. Recruitment of small synergistic movement makes a good pianist. Annu Int Conf IEEE Eng Med Biol Soc 2015; 2015:242-245. [PMID: 26736245 DOI: 10.1109/embc.2015.7318345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Time-varying synergies from kinematic data can be used to discern fundamental patterns of movement. We show through simultaneous extraction of synergies from both novice and experienced pianists that movement common to both groups can be identified. The extracted synergies successfully allow for the majority of the variability of the data to be accounted for by a limited number of components. Furthermore, classification of the weightings representing the recruitment of each of the synergies accurately distinguishes between the piano playing of the two groups of subjects. However, the major differences between the two groups lie not in the synergies representing the majority of the variance of the data but in the recruitment of smaller synergies.
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28
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Poon CS, Tin C. Mechanism of augmented exercise hyperpnea in chronic heart failure and dead space loading. Respir Physiol Neurobiol 2012; 186:114-30. [PMID: 23274121 DOI: 10.1016/j.resp.2012.12.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 12/14/2012] [Indexed: 12/16/2022]
Abstract
Patients with chronic heart failure (CHF) suffer increased alveolar VD/VT (dead-space-to-tidal-volume ratio), yet they demonstrate augmented pulmonary ventilation such that arterial [Formula: see text] ( [Formula: see text] ) remains remarkably normal from rest to moderate exercise. This paradoxical effect suggests that the control law governing exercise hyperpnea is not merely determined by metabolic CO2 production ( [Formula: see text] ) per se but is responsive to an apparent (real-feel) metabolic CO2 load ( [Formula: see text] ) that also incorporates the adverse effect of physiological VD/VT on pulmonary CO2 elimination. By contrast, healthy individuals subjected to dead space loading also experience augmented ventilation at rest and during exercise as with increased alveolar VD/VT in CHF, but the resultant response is hypercapnic instead of eucapnic, as with CO2 breathing. The ventilatory effects of dead space loading are therefore similar to those of increased alveolar VD/VT and CO2 breathing combined. These observations are consistent with the hypothesis that the increased series VD/VT in dead space loading adds to [Formula: see text] as with increased alveolar VD/VT in CHF, but this is through rebreathing of CO2 in dead space gas thus creating a virtual (illusory) airway CO2 load within each inspiration, as opposed to a true airway CO2 load during CO2 breathing that clogs the mechanism for CO2 elimination through pulmonary ventilation. Thus, the chemosensing mechanism at the respiratory controller may be responsive to putative drive signals mediated by within-breath [Formula: see text] oscillations independent of breath-to-breath fluctuations of the mean [Formula: see text] level. Skeletal muscle afferents feedback, while important for early-phase exercise cardioventilatory dynamics, appears inconsequential for late-phase exercise hyperpnea.
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Affiliation(s)
- Chi-Sang Poon
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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Tin C, Song G, Poon CS. Hypercapnia attenuates inspiratory amplitude and expiratory time responsiveness to hypoxia in vagotomized and vagal-intact rats. Respir Physiol Neurobiol 2012; 181:79-87. [PMID: 22326640 DOI: 10.1016/j.resp.2012.01.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 01/19/2012] [Accepted: 01/24/2012] [Indexed: 10/14/2022]
Abstract
A negative influence of central chemosensitivity on peripheral chemoreflex response has been demonstrated recently in a decerebrate-vagotomized rat preparation in situ with separate carotid body and brainstem perfusions. Here, we report similar negative influences of hypercapnia on the hypoxic respiratory response in anesthetized, spontaneously breathing rats before and after vagotomy and anesthetized, artificially ventilated rats after vagotomy. Baseline breathing patterns and responsiveness to hypercapnia and hypoxia varied widely between the three respiratory modes. Despite this, the responses in inspiratory amplitude and expiratory duration (and hence respiratory frequency and neural ventilation) to hypoxia varied inversely with the background CO2 level in all three groups. Results demonstrate a hypoadditive hypercapnic-hypoxic interaction in vivo that resembles the hypoadditive central-peripheral chemoreceptor interaction in situ for these respiratory variables in the rat, regardless of differences in vagal feedback, body temperature and ventilation method. These observations stand in contrast to previous reports of hyperadditive peripheral-central chemoreceptor interaction.
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Affiliation(s)
- Chung Tin
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Song G, Tin C, Giacometti E, Poon CS. Habituation without NMDA Receptor-Dependent Desensitization of Hering-Breuer Apnea Reflex in a Mecp2 Mutant Mouse Model of Rett Syndrome. Front Integr Neurosci 2011; 5:6. [PMID: 21629824 PMCID: PMC3096835 DOI: 10.3389/fnint.2011.00006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Accepted: 04/12/2011] [Indexed: 01/20/2023] Open
Abstract
Non-associative learning is a basic neuroadaptive behavior exhibited in almost all animal species and sensory modalities but its functions and mechanisms in the mammalian brain are poorly understood. Previous studies have identified two distinct forms of non-associative learning in the classic Hering-Breuer inflation reflex (HBIR) induced apnea in rats: NMDA receptor (NMDAR)-independent habituation in a primary vagal pathway and NMDAR-dependent desensitization in a secondary pontine pathway. Here, we show that abnormal non-associative learning of the HBIR may underlie the endophenotypic tachypnea in an animal model of Rett syndrome (RTT), an autism-spectrum disorder caused by mutations in the X-linked gene encoding methyl-CpG-binding protein 2 (MECP2). Mecp2(+/-) symptomatic mice on a mixed-strain background demonstrated significantly increased resting respiratory frequency with shortened expiration and normal inspiratory duration compared with asymptomatic mutants and wild-type controls, a phenotype that is characteristic of girls with RTT. Low-intensity electrical stimulation of the vagus nerve elicited fictive HBIR with time-dependent habituation in both Mecp2(+/-) and wild-type mice. However, time-dependent desensitization of the HBIR was evidenced only in wild-type controls and asymptomatic mutant mice but was absent or suppressed in Mecp2(+/-) symptomatic mice or in wild-type mice after blockade of NMDAR with dizocilpine. Remarkably, ∼50% of the Mecp2(+/-) mice developed these X-linked phenotypes despite somatic mosaicism. Such RTT-like respiratory endophenotypes in mixed-strain Mecp2(+/-) mice differed from those previously reported in Mecp2(-/y) mice on pure C57BL/6J background. These findings provide the first evidence indicating that impaired NMDAR-dependent desensitization of the HBIR may contribute to the endophenotypic tachypnea in RTT.
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Affiliation(s)
- Gang Song
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology Cambridge, MA, USA
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Poon CS, Song G, Tin C. Bilateral Lesions of Pontine Kölliker-Fuse Nuclei Provoke Apnea instead of Apneusis in Anesthetized Adult Rats. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 669:185-8. [DOI: 10.1007/978-1-4419-5692-7_37] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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Abstract
The classic Hering-Breuer inflation reflex (HBIR) is a widely held tenet for understanding the lung volume-related vagal control of respiratory rhythm. Recent evidence, however, has revealed that the fictive HBIR elicited by electrical vagal stimulation in rats is not static but may be attenuated centrally by two forms of non-associative learning (habituation and desensitization) that continually mitigate the reflex effects with exponential adaptations like a differentiator or high-pass filter. Desensitization is analogous to habituation but exhibits an explicit short-term memory (STM) in the form of a rebound response with exponential decay during recovery from stimulation. To investigate whether such learning and memory effects are lung volume related and use-dependent (practice makes perfect), we compared the time-dependent changes in inspiratory and expiratory durations (t(I) and t(E)) during and after 1 or 8 min unilateral lung inflation or high-frequency, low-intensity vagal stimulation in anaesthetized, uni- or bi-vagotomized rats. Unilateral lung inflation and vagal stimulation both elicited abrupt shortening of t(I) and lengthening of t(E) (HBIR effects) and gradual habituation and desensitization throughout the 1 or 8 min test period, followed by rebound responses in t(I) and t(E) with exponential recovery (STM effects) in the post-test period. In both cases, the STM time constants for t(I) and t(E) were significantly longer with the 8 min test than with the 1 min test (17-45 versus 4-11 s, P < 0.01). We conclude that the HBIR and its central habituation and desensitization are mediated peripherally by lung volume-related vagal afferents, and that the STM of desensitization is use-dependent. The translational implications of these findings are discussed.
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Poon CS, Tin C, Yu Y. Homeostasis of exercise hyperpnea and optimal sensorimotor integration: the internal model paradigm. Respir Physiol Neurobiol 2007; 159:1-13; discussion 14-20. [PMID: 17416554 PMCID: PMC2225386 DOI: 10.1016/j.resp.2007.02.020] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Revised: 02/28/2007] [Accepted: 02/28/2007] [Indexed: 11/16/2022]
Abstract
Homeostasis is a basic tenet of biomedicine and an open problem for many physiological control systems. Among them, none has been more extensively studied and intensely debated than the dilemma of exercise hyperpnea - a paradoxical homeostatic increase of respiratory ventilation that is geared to metabolic demands instead of the normal chemoreflex mechanism. Classical control theory has led to a plethora of "feedback/feedforward control" or "set point" hypotheses for homeostatic regulation, yet so far none of them has proved satisfactory in explaining exercise hyperpnea and its interactions with other respiratory inputs. Instead, the available evidence points to a far more sophisticated respiratory controller capable of integrating multiple afferent and efferent signals in adapting the ventilatory pattern toward optimality relative to conflicting homeostatic, energetic and other objectives. This optimality principle parsimoniously mimics exercise hyperpnea, chemoreflex and a host of characteristic respiratory responses to abnormal gas exchange or mechanical loading/unloading in health and in cardiopulmonary diseases - all without resorting to a feedforward "exercise stimulus". Rather, an emergent controller signal encoding the projected metabolic level is predicted by the principle as an exercise-induced 'mental percept' or 'internal model', presumably engendered by associative learning (operant conditioning or classical conditioning) which achieves optimality through continuous identification of, and adaptation to, the causal relationship between respiratory motor output and resultant chemical-mechanical afferent feedbacks. This internal model self-tuning adaptive control paradigm opens a new challenge and exciting opportunity for experimental and theoretical elucidations of the mechanisms of respiratory control - and of homeostatic regulation and sensorimotor integration in general.
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Affiliation(s)
- Chi-Sang Poon
- Harvard-MIT Division of Health Sciences and Technology, Bldg. 56-046, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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Wang G, Song G, Tin C, Poon CS. Nonassociative learning in expiratory inhibition of inspiratory motor output: an experimental and modeling study. Conf Proc IEEE Eng Med Biol Soc 2007; 2005:5843-6. [PMID: 17281588 DOI: 10.1109/iembs.2005.1615818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The present study is to characterize the habituation and re-sensitization in the inspiratory inhibition produced by the Bötzinger Complex (BOt.C) and the modulation effects of raphe pallidus (RP) and locus coeruleus (LC). Experiments were done on urethane anaesthetized, vagotomized, paralyzed and artificially ventilated rabbits. Electrical stimulation of the BOt.C (25 ..A, 80 Hz, 15 sec) caused inspiratory inhibition that became gradually adapted with the continuation of the stimulation. At the offset of this stimulation, the phrenic discharge showed temporary rebound increase in amplitude. The adaptation-rebound response pattern resembled a neural differentiator. Pre-stimulation of the RP or LC (50 ..A, 80 Hz, 10 sec) facilitated the adaptation of BOt.C's inspiratory inhibition and the post-stimulus rebound. The results indicate the existence of nonassociative learning (habituation and re-sensitization) in the inspiratory inhibition circuit and the modulation of this nonassociative learning by RP and LC.
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Affiliation(s)
- G Wang
- Institute of Physiology, School of Medicine, Shandong University, P. R. China wanggm@ sdu.edu.cn
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Abstract
Internal models and adaptive controls are empirical and mathematical paradigms that have evolved separately to describe learning control processes in brain systems and engineering systems, respectively. This paper presents a comprehensive appraisal of the correlation between these paradigms with a view to forging a unified theoretical framework that may benefit both disciplines. It is suggested that the classic equilibrium-point theory of impedance control of arm movement is analogous to continuous gain-scheduling or high-gain adaptive control within or across movement trials, respectively, and that the recently proposed inverse internal model is akin to adaptive sliding control originally for robotic manipulator applications. Modular internal models' architecture for multiple motor tasks is a form of multi-model adaptive control. Stochastic methods, such as generalized predictive control, reinforcement learning, Bayesian learning and Hebbian feedback covariance learning, are reviewed and their possible relevance to motor control is discussed. Possible applicability of a Luenberger observer and an extended Kalman filter to state estimation problems-such as sensorimotor prediction or the resolution of vestibular sensory ambiguity-is also discussed. The important role played by vestibular system identification in postural control suggests an indirect adaptive control scheme whereby system states or parameters are explicitly estimated prior to the implementation of control. This interdisciplinary framework should facilitate the experimental elucidation of the mechanisms of internal models in sensorimotor systems and the reverse engineering of such neural mechanisms into novel brain-inspired adaptive control paradigms in future.
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Affiliation(s)
- Chung Tin
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Chi-Sang Poon
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Abstract
We have recently shown that CD8+ T cells mediate clearance of rotavirus infection in mice. B-cell-deficient J(H)D knockout (-/-) mice depleted of CD8+ T cells become chronically infected with murine rotavirus, and beta2 microglobulin -/- and other mice depleted of CD8+ T cells have a 1- to 4-day delay in clearance of primary rotavirus infection. A role for CD8+ T cells in protection from reinfection with rotavirus was suggested by these studies, because J(H)D -/- mice rechallenged 6 to 8 weeks after primary infection shed smaller quantities of viral antigen and for fewer days than naive mice. Here we show that 8, 11, 13, and 18 days after primary infection the J(H)D -/- mice are almost completely resistant to reinfection and that they are still partially protected from reinfection 6 weeks, 5 months, and 8 months after primary infection. Protection against reinfection was dependent on CD8+ T cells, since J(H)D -/- mice depleted of CD8+ T cells by administration of an anti-CD8 monoclonal antibody became chronically infected with rotavirus upon rechallenge 13 days, 18 days, 6 weeks, and 5 months after primary infection. Thus, CD8+ T cells can actively mediate almost complete short-term and partial long-term protection from reinfection.
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Affiliation(s)
- M A Franco
- Veterans Administration Palo Alto Health Care System and Department of Medicine, Stanford University School of Medicine, California 94305, USA.
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Franco MA, Tin C, Rott LS, VanCott JL, McGhee JR, Greenberg HB. Evidence for CD8+ T-cell immunity to murine rotavirus in the absence of perforin, fas, and gamma interferon. J Virol 1997; 71:479-86. [PMID: 8985374 PMCID: PMC191075 DOI: 10.1128/jvi.71.1.479-486.1997] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We recently showed that class I-restricted CD8+ T cells mediate clearance of primary rotavirus infection in mice: JHD knockout (JHD -/-) (B-cell-deficient) mice depleted of CD8+ T cells become chronically infected with murine rotavirus, and beta2 microglobulin knockout (beta2m -/-) mice have delayed but complete clearance of primary rotavirus infection. In the present work we have analyzed the mechanism used by CD8+ T cells to clear rotavirus infection. We first determined that perforin knockout (perforin -/-) mice and lpr (fas-deficient) mice clear rotavirus infection with the same kinetics as control mice. When perforin -/- or perforin +/+ mice were depleted of CD8+ T cells by administration of an anti-CD8 monoclonal antibody, they showed a delay of 1 to 2 days in the clearance of rotavirus infection compared to the clearance time for untreated control mice, indicating that CD8+ T cells in both groups of mice participate in the resolution of primary rotavirus infection. In addition, passively transferred CD8+ T cells from rotavirus-infected perforin +/+ and perforin -/- mice were able to mediate viral clearance in Rag 2 knockout (Rag 2 -/-) mice chronically infected with rotavirus with similar kinetics, suggesting that CD8+ T cells from perforin -/- mice are as efficient as CD8+ T cells from perforin +/+ mice in clearing a rotavirus infection. Gamma interferon (IFN-gamma) was also shown to be unnecessary for the antirotavirus effect of CD8+ T cells: IFN-gamma knockout (IFN-gamma -/-) mice and JHD -/-, perforin -/-, and perforin +/+ mice depleted of IFN-gamma by administration of an anti-IFN-gamma monoclonal antibody cleared rotavirus infection with the same kinetics as those for control mice. Hence, CD8+ T cells have an antirotaviral effect that is not mediated by perforin and appears to be independent of fas and the release of IFN-gamma.
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Affiliation(s)
- M A Franco
- Department of Medicine, Stanford University School of Medicine, California 94305, USA.
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