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Cangalaya C, Sun W, Stoyanov S, Dunay IR, Dityatev A. Integrity of neural extracellular matrix is required for microglia-mediated synaptic remodeling. Glia 2024; 72:1874-1892. [PMID: 38946065 DOI: 10.1002/glia.24588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 06/12/2024] [Accepted: 06/18/2024] [Indexed: 07/02/2024]
Abstract
Microglia continuously remodel synapses, which are embedded in the extracellular matrix (ECM). However, the mechanisms, which govern this process remain elusive. To investigate the influence of the neural ECM in synaptic remodeling by microglia, we disrupted ECM integrity by injection of chondroitinase ABC (ChABC) into the retrosplenial cortex of healthy adult mice. Using in vivo two-photon microscopy we found that ChABC treatment increased microglial branching complexity and ECM phagocytic capacity and decreased spine elimination rate under basal conditions. Moreover, ECM attenuation largely prevented synaptic remodeling following synaptic stress induced by photodamage of single synaptic elements. These changes were associated with less stable and smaller microglial contacts at the synaptic damage sites, diminished deposition of calreticulin and complement proteins C1q and C3 at synapses and impaired expression of microglial CR3 receptor. Thus, our findings provide novel insights into the function of the neural ECM in deposition of complement proteins and synaptic remodeling by microglia.
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Affiliation(s)
- Carla Cangalaya
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Weilun Sun
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
- Department of Pharmacology, School of Pharmaceutical Sciences, Jilin University, Changchun, China
| | - Stoyan Stoyanov
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Ildiko Rita Dunay
- Institute of Inflammation and Neurodegeneration, Otto von Guericke University Magdeburg, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Alexander Dityatev
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
- Medical Faculty, Otto von Guericke University, Magdeburg, Germany
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2
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Brown BL, Anil N, States G, Whittemore SR, Magnuson DSK. Long ascending propriospinal neurons are heterogenous and subject to spinal cord injury induced anatomic plasticity. Exp Neurol 2024; 373:114631. [PMID: 38070723 PMCID: PMC10922963 DOI: 10.1016/j.expneurol.2023.114631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/15/2023] [Accepted: 11/29/2023] [Indexed: 12/21/2023]
Abstract
Long ascending propriospinal neurons (LAPNs) are a subset of spinal interneurons that provide direct connectivity between distant spinal segments. Here, we focus specifically on an anatomically defined population of "inter-enlargement" LAPNs with cell bodies at L2/3 and terminals at C5/6. Previous studies showed that silencing LAPNs in awake and freely moving animals disrupted interlimb coordination of the hindlimbs, forelimbs, and heterolateral limb pairs. Surprisingly, despite a proportion of LAPNs being anatomically intact post- spinal cord injury (SCI), silencing them improved locomotor function but only influenced coordination of the hindlimb pair. Given the functional significance of LAPNs pre- and post-SCI, we characterized their anatomy and SCI-induced anatomical plasticity. This detailed anatomical characterization revealed three morphologically distinct subsets of LAPNs that differ in soma size, neurite complexity and/or neurite orientation. Following a mild thoracic contusive SCI there was a marked shift in neurite orientation in two of the LAPN subsets to a more dorsoventral orientation, and collateral densities decreased in the cervical enlargement but increased just caudal to the injury epicenter. These post-SCI anatomical changes potentially reflect maladaptive plasticity and an effort to establish new functional inputs from sensory afferents that sprout post-SCI to achieve circuitry homeostasis.
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Affiliation(s)
- Brandon L Brown
- Interdisciplinary Program in Translational Neuroscience, University of Louisville, Louisville, KY, United States; Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States; Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY, United States
| | - Neha Anil
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States; Department of Bioengineering, J.B. Speed School of Engineering, University of Louisville, Louisville, KY, United States
| | - Gregory States
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States; Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY, United States
| | - Scott R Whittemore
- Interdisciplinary Program in Translational Neuroscience, University of Louisville, Louisville, KY, United States; Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States; Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY, United States; Department of Neurological Surgery, School of Medicine, University of Louisville, Louisville, KY, United States
| | - David S K Magnuson
- Interdisciplinary Program in Translational Neuroscience, University of Louisville, Louisville, KY, United States; Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States; Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY, United States; Department of Bioengineering, J.B. Speed School of Engineering, University of Louisville, Louisville, KY, United States; Department of Neurological Surgery, School of Medicine, University of Louisville, Louisville, KY, United States.
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3
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Wang IF, Wang Y, Yang YH, Huang GJ, Tsai KJ, Shen CKJ. Activation of a hippocampal CREB-pCREB-miRNA-MEF2 axis modulates individual variation of spatial learning and memory capability. Cell Rep 2021; 36:109477. [PMID: 34348143 DOI: 10.1016/j.celrep.2021.109477] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/07/2021] [Accepted: 07/13/2021] [Indexed: 11/30/2022] Open
Abstract
Phenotypic variation is a fundamental prerequisite for cell and organism evolution by natural selection. Whereas the role of stochastic gene expression in phenotypic diversity of genetically identical cells is well studied, not much is known regarding the relationship between stochastic gene expression and individual behavioral variation in animals. We demonstrate that a specific miRNA (miR-466f-3p) is upregulated in the hippocampus of a portion of individual inbred mice upon a Morris water maze task. Significantly, miR-466f-3p positively regulates the neuron morphology, function and spatial learning, and memory capability of mice. Mechanistically, miR-466f-3p represses translation of MEF2A, a negative regulator of learning/memory. Finally, we show that varied upregulation of hippocampal miR-466f-3p results from randomized phosphorylation of hippocampal cyclic AMP (cAMP)-response element binding (CREB) in individuals. This finding of modulation of spatial learning and memory via a randomized hippocampal signaling axis upon neuronal stimulation represents a demonstration of how variation in tissue gene expression lead to varied animal behavior.
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Affiliation(s)
- I-Fang Wang
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei 11031, Taiwan; Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Yihan Wang
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Yi-Hua Yang
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei 11031, Taiwan; Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 70403, Taiwan; Research Center of Clinical Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70403, Taiwan
| | - Guo-Jen Huang
- Department and Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan; Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou 33302, Taiwan
| | - Kuen-Jer Tsai
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 70403, Taiwan; Research Center of Clinical Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70403, Taiwan.
| | - Che-Kun James Shen
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei 11031, Taiwan; Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan.
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Kim JH, Chung KH, Hwang YR, Park HR, Kim HJ, Kim HG, Kim HR. Exposure to RF-EMF Alters Postsynaptic Structure and Hinders Neurite Outgrowth in Developing Hippocampal Neurons of Early Postnatal Mice. Int J Mol Sci 2021; 22:ijms22105340. [PMID: 34069478 PMCID: PMC8159076 DOI: 10.3390/ijms22105340] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/13/2021] [Accepted: 05/13/2021] [Indexed: 12/23/2022] Open
Abstract
Exposure to radiofrequency electromagnetic fields (RF-EMFs) has increased rapidly in children, but information on the effects of RF-EMF exposure to the central nervous system in children is limited. In this study, pups and dams were exposed to whole-body RF-EMF at 4.0 W/kg specific absorption rate (SAR) for 5 h per day for 4 weeks (from postnatal day (P) 1 to P28). The effects of RF-EMF exposure on neurons were evaluated by using both pups' hippocampus and primary cultured hippocampal neurons. The total number of dendritic spines showed statistically significant decreases in the dentate gyrus (DG) but was not altered in the cornu ammonis (CA1) in hippocampal neurons. In particular, the number of mushroom-type dendritic spines showed statistically significant decreases in the CA1 and DG. The expression of glutamate receptors was decreased in mushroom-type dendritic spines in the CA1 and DG of hippocampal neurons following RF-EMF exposure. The expression of brain-derived neurotrophic factor (BDNF) in the CA1 and DG was significantly lower statistically in RF-EMF-exposed mice. The number of post-synaptic density protein 95 (PSD95) puncta gradually increased over time but was significantly decreased statistically at days in vitro (DIV) 5, 7, and 9 following RF-EMF exposure. Decreased BDNF expression was restricted to the soma and was not observed in neurites of hippocampal neurons following RF-EMF exposure. The length of neurite outgrowth and number of branches showed statistically significant decreases, but no changes in the soma size of hippocampal neurons were observed. Further, the memory index showed statistically significant decreases in RF-EMF-exposed mice, suggesting that decreased synaptic density following RF-EMF exposure at early developmental stages may affect memory function. Collectively, these data suggest that hindered neuronal outgrowth following RF-EMF exposure may decrease overall synaptic density during early neurite development of hippocampal neurons.
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Affiliation(s)
- Ju Hwan Kim
- Department of Pharmacology, College of Medicine, Dankook University, Cheonan 31116, Korea; (J.H.K.); (H.R.P.); (H.-G.K.)
| | - Kyung Hwun Chung
- Hyangseol Medical Research Center, Soonchunhyang University Bucheon Hospital, Bucheon 14584, Korea;
| | - Yeong Ran Hwang
- Department of Physiology, College of Medicine, Dankook University, Cheonan 31116, Korea; (Y.R.H.); (H.J.K.)
| | - Hye Ran Park
- Department of Pharmacology, College of Medicine, Dankook University, Cheonan 31116, Korea; (J.H.K.); (H.R.P.); (H.-G.K.)
| | - Hee Jung Kim
- Department of Physiology, College of Medicine, Dankook University, Cheonan 31116, Korea; (Y.R.H.); (H.J.K.)
| | - Hyung-Gun Kim
- Department of Pharmacology, College of Medicine, Dankook University, Cheonan 31116, Korea; (J.H.K.); (H.R.P.); (H.-G.K.)
| | - Hak Rim Kim
- Department of Pharmacology, College of Medicine, Dankook University, Cheonan 31116, Korea; (J.H.K.); (H.R.P.); (H.-G.K.)
- Correspondence: ; Tel.: +82-41-550-3935
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Cangalaya C, Stoyanov S, Fischer KD, Dityatev A. Light-induced engagement of microglia to focally remodel synapses in the adult brain. eLife 2020; 9:e58435. [PMID: 32808923 PMCID: PMC7470825 DOI: 10.7554/elife.58435] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/18/2020] [Indexed: 12/18/2022] Open
Abstract
Microglia continuously monitor synapses, but active synaptic remodeling by microglia in mature healthy brains is rarely directly observed. We performed targeted photoablation of single synapses in mature transgenic mice expressing fluorescent labels in neurons and microglia. The photodamage focally increased the duration of microglia-neuron contacts, and dramatically exacerbated both the turnover of dendritic spines and presynaptic boutons as well as the generation of new filopodia originating from spine heads or boutons. The results of microglia depletion confirmed that elevated spine turnover and the generation of presynaptic filopodia are microglia-dependent processes.
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Affiliation(s)
- Carla Cangalaya
- ESF International Graduate School on Analysis, Imaging and Modelling of Neuronal and Inflammatory ProcessesMagdeburgGermany
- Institut für Biochemie und Zellbiologie, Otto-von-Guericke-University, Medical FacultyMagdeburgGermany
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE)MagdeburgGermany
| | - Stoyan Stoyanov
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE)MagdeburgGermany
| | - Klaus-Dieter Fischer
- Institut für Biochemie und Zellbiologie, Otto-von-Guericke-University, Medical FacultyMagdeburgGermany
| | - Alexander Dityatev
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE)MagdeburgGermany
- Medical Faculty, Otto-von-Guericke UniversityMagdeburgGermany
- Center for Behavioral Brain Sciences (CBBS)MagdeburgGermany
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Bannatyne BA, Hao ZZ, Dyer GMC, Watanabe M, Maxwell DJ, Berkowitz A. Neurotransmitters and Motoneuron Contacts of Multifunctional and Behaviorally Specialized Turtle Spinal Cord Interneurons. J Neurosci 2020; 40:2680-2694. [PMID: 32066584 PMCID: PMC7096148 DOI: 10.1523/jneurosci.2200-19.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 01/31/2020] [Accepted: 02/06/2020] [Indexed: 12/11/2022] Open
Abstract
The spinal cord can appropriately generate diverse movements, even without brain input and movement-related sensory feedback, using a combination of multifunctional and behaviorally specialized interneurons. The adult turtle spinal cord can generate motor patterns underlying forward swimming, three forms of scratching, and limb withdrawal (flexion reflex). We previously described turtle spinal interneurons activated during both scratching and swimming (multifunctional interneurons), interneurons activated during scratching but not swimming (scratch-specialized interneurons), and interneurons activated during flexion reflex but not scratching or swimming (flexion reflex-selective interneurons). How multifunctional and behaviorally specialized turtle spinal interneurons affect downstream neurons was unknown. Here, we recorded intracellularly from spinal interneurons activated during these motor patterns in turtles of both sexes in vivo and filled each with dyes. We labeled motoneurons using choline acetyltransferase antibodies or earlier intraperitoneal FluoroGold injection and used immunocytochemistry of interneuron axon terminals to identify their neurotransmitter(s) and putative synaptic contacts with motoneurons. We found that multifunctional interneurons are heterogeneous with respect to neurotransmitter, with some glutamatergic and others GABAergic or glycinergic, and can directly contact motoneurons. Also, scratch-specialized interneurons are heterogeneous with respect to neurotransmitter and some directly contact motoneurons. Thus, scratch-specialized interneurons might directly excite motoneurons that are more strongly activated during scratching than forward swimming, such as hip-flexor motoneurons. Finally, and surprisingly, we found that some motoneurons are behaviorally specialized, for scratching or flexion reflex. Thus, either some limb muscles are only used for a subset of limb behaviors or some limb motoneurons are only recruited during certain limb behaviors.SIGNIFICANCE STATEMENT Both multifunctional and behaviorally specialized spinal cord interneurons have been described in turtles, but their outputs are unknown. We studied responses of multifunctional interneurons (activated during swimming and scratching) and scratch-specialized interneurons, filled each with dyes, and used immunocytochemistry to determine their neurotransmitters and contacts with motoneurons. We found that both multifunctional and scratch-specialized interneurons are heterogeneous with respect to neurotransmitter, with some excitatory and others inhibitory. We found that some multifunctional and some scratch-specialized interneurons directly contact motoneurons. Scratch-specialized interneurons may excite motoneurons that are more strongly activated during scratching than swimming, such as hip-flexor motoneurons, or inhibit their antagonists, hip-extensor motoneurons. Surprisingly, we also found that some motoneurons are behaviorally specialized, for scratching or for flexion reflex.
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Affiliation(s)
- B Anne Bannatyne
- Spinal Cord Group, Institute of Neuroscience and Psychology, University of Glasgow, United Kingdom G12 8QQ
| | - Zhao-Zhe Hao
- Department of Biology and Cellular and Behavioral Neurobiology Graduate Program, University of Oklahoma, Norman, Oklahoma 73019, and
| | - Georgia M C Dyer
- Spinal Cord Group, Institute of Neuroscience and Psychology, University of Glasgow, United Kingdom G12 8QQ
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University Faculty of Medicine, Sapporo 060-8638, Japan
| | - David J Maxwell
- Spinal Cord Group, Institute of Neuroscience and Psychology, University of Glasgow, United Kingdom G12 8QQ
| | - Ari Berkowitz
- Department of Biology and Cellular and Behavioral Neurobiology Graduate Program, University of Oklahoma, Norman, Oklahoma 73019, and
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Stein PSG. Central pattern generators in the turtle spinal cord: selection among the forms of motor behaviors. J Neurophysiol 2018; 119:422-440. [PMID: 29070633 PMCID: PMC5867383 DOI: 10.1152/jn.00602.2017] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 10/16/2017] [Accepted: 10/17/2017] [Indexed: 12/29/2022] Open
Abstract
Neuronal networks in the turtle spinal cord have considerable computational complexity even in the absence of connections with supraspinal structures. These networks contain central pattern generators (CPGs) for each of several behaviors, including three forms of scratch, two forms of swim, and one form of flexion reflex. Each behavior is activated by a specific set of cutaneous or electrical stimuli. The process of selection among behaviors within the spinal cord has multisecond memories of specific motor patterns. Some spinal cord interneurons are partially shared among several CPGs, whereas other interneurons are active during only one type of behavior. Partial sharing is a proposed mechanism that contributes to the ability of the spinal cord to generate motor pattern blends with characteristics of multiple behaviors. Variations of motor patterns, termed deletions, assist in characterization of the organization of the pattern-generating components of CPGs. Single-neuron recordings during both normal and deletion motor patterns provide support for a CPG organizational structure with unit burst generators (UBGs) whose members serve a direction of a specific degree of freedom of the hindlimb, e.g., the hip-flexor UBG, the hip-extensor UBG, the knee-flexor UBG, the knee-extensor UBG, etc. The classic half-center hypothesis that includes all the hindlimb flexors in a single flexor half-center and all the hindlimb extensors in a single extensor half-center lacks the organizational complexity to account for the motor patterns produced by turtle spinal CPGs. Thus the turtle spinal cord is a valuable model system for studies of mechanisms responsible for selection and generation of motor behaviors. NEW & NOTEWORTHY The concept of the central pattern generator (CPG) is a major tenet in motor neuroethology that has influenced the design and interpretations of experiments for over a half century. This review concentrates on the turtle spinal cord and describes studies from the 1970s to the present responsible for key developments in understanding the CPG mechanisms responsible for the selection and production of coordinated motor patterns during turtle hindlimb motor behaviors.
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Affiliation(s)
- Paul S G Stein
- Department of Biology, Washington University , St. Louis, Missouri
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Protective Effects of Wogonin against Alzheimer's Disease by Inhibition of Amyloidogenic Pathway. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2017; 2017:3545169. [PMID: 28680449 PMCID: PMC5478820 DOI: 10.1155/2017/3545169] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/15/2017] [Accepted: 04/12/2017] [Indexed: 11/17/2022]
Abstract
One of the pathogenic systems of Alzheimer's disease (AD) is the formation of β-amyloid plaques in the brains of patients, and amyloidogenic activity becomes one of the therapeutic targets. Here, we report wogonin, one of the major active constituting components in Scutellaria baicalensis, which has the neuroprotective effects on amyloid-β peptides- (Aβ-) induced toxicity. Oral wogonin treatment improved the performance of triple transgenic AD mice (h-APPswe, h-Tau P301L, and h-PS1 M146V) on the Morris water maze, Y-maze, and novel object recognition. Furthermore, wogonin activated the neurite outgrowth of AD cells by increasing neurite length and complexity of Tet-On Aβ42-GFP SH-SY5Y neuroblastoma cells (AD cells) and attenuated amyloidogenic pathway by decreasing the levels of β-secretase, APP β-C-terminal fragment, Aβ-aggregation, and phosphorylated Tau. Wogonin also increased mitochondrial membrane potential (∆ψm) and protected against apoptosis by reducing the expression of Bax and cleaved PARP. Collectively, these results conclude that wogonin may be a promising multifunctional drug candidate for AD.
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