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1.
Cell Stem Cell ; 30(10): 1331-1350.e11, 2023 10 05.
Article in English | MEDLINE | ID: mdl-37802038

ABSTRACT

Mesial temporal lobe epilepsy (MTLE) is the most common focal epilepsy. One-third of patients have drug-refractory seizures and are left with suboptimal therapeutic options such as brain tissue-destructive surgery. Here, we report the development and characterization of a cell therapy alternative for drug-resistant MTLE, which is derived from a human embryonic stem cell line and comprises cryopreserved, post-mitotic, medial ganglionic eminence (MGE) pallial-type GABAergic interneurons. Single-dose intrahippocampal delivery of the interneurons in a mouse model of chronic MTLE resulted in consistent mesiotemporal seizure suppression, with most animals becoming seizure-free and surviving longer. The grafted interneurons dispersed locally, functionally integrated, persisted long term, and significantly reduced dentate granule cell dispersion, a pathological hallmark of MTLE. These disease-modifying effects were dose-dependent, with a broad therapeutic range. No adverse effects were observed. These findings support an ongoing phase 1/2 clinical trial (NCT05135091) for drug-resistant MTLE.


Subject(s)
Epilepsy, Temporal Lobe , Hippocampus , Mice , Animals , Humans , Hippocampus/pathology , Epilepsy, Temporal Lobe/pathology , Epilepsy, Temporal Lobe/surgery , Seizures/pathology , Seizures/surgery , Interneurons/physiology , Brain/pathology
2.
Cells ; 11(18)2022 09 07.
Article in English | MEDLINE | ID: mdl-36139362

ABSTRACT

Hypoxia, a typical feature of locally advanced solid tumors including prostate cancer, is a critical contributor to tumor progression and causes resistance to therapy. In this study, we investigated the effects of chrysin on tumor progression in hypoxic PC-3 cells. Chrysin exerted a significant inhibitory effect on 3D cell growth under normoxic and hypoxic conditions. It also decreased the hypoxia-induced vasculogenic mimicry and attenuated the expression of HIF-1α and VE-cadherin. Chrysin inhibited HIF-1α accumulation in a concentration- and time-dependent manner in hypoxic PC-3 cells, while also suppressing the expression of HIF-1α by inhibiting SPHK-1 in both CoCl2 and hypoxic PC-3 cells. At high concentrations of chrysin, there was a greater increase in apoptosis in the hypoxic cells compared to that in normoxic cells, which was accompanied by sub-G1 phase arrest. Chrysin-induced apoptosis inhibited VEGF and Bcl-2 and induced the cleavage of PARP and caspase-3. SPHK-1 knockdown induced apoptosis and inhibited epithelial-mesenchymal transition. Consistent with the in vitro data, 50 mg/kg of chrysin suppressed the tumor growth of PC-3 xenografts by 80.4% compared to that in the untreated control group. The immunohistochemistry of tumor tissues revealed decreased Ki-67, HIF-1α, and VEGF expression in the chrysin-treated group compared to an untreated control. Western blotting data for tumor tissues showed that chrysin treatment decreased SPHK-1, HIF-1α, and PARP expression while inducing caspase-3 cleavage. Overall, our findings suggest that chrysin exerts anti-tumor activity by inhibiting SPHK-1/HIF-1α signaling and thus represents a potent chemotherapeutic agent for hypoxia, which promotes cancer progression and is related to poor prognoses in prostate cancer patients.


Subject(s)
Prostatic Neoplasms , Vascular Endothelial Growth Factor A , Caspase 3/metabolism , Cell Line, Tumor , Flavonoids , Humans , Hypoxia/metabolism , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Ki-67 Antigen/metabolism , Male , PC-3 Cells , Poly(ADP-ribose) Polymerase Inhibitors/pharmacology , Prostatic Neoplasms/pathology , Proto-Oncogene Proteins c-bcl-2/metabolism , Signal Transduction , Vascular Endothelial Growth Factor A/metabolism
3.
Mol Biol Rep ; 48(3): 2173-2181, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33630206

ABSTRACT

BACKGROUND: The pawpaw tree has several beneficial effects. However, no studies have been conducted to address the mechanisms underlying the cytotoxic effects of pawpaw extracts against cancer cells, and no study has investigated the anti-inflammatory effects. Hence, in this study, the growth-inhibitory effects of pawpaw (Asimina triloba [L.] Dunal) extracts against gastric (AGS) and cervical (HeLa) cancer cells and the inhibitory effects of pawpaw extracts against inflammatory factors (NO, TNF-α, IL-6, iNOS, and COX-2) were investigated. METHODS AND RESULTS: The viability of AGS and HeLa cells, the analysis of cell cycle, and the expression of apoptosis marker protein were determined using MTT assay, FACS, western blotting, and TUNEL assays. The inflammatory factors were determined using Griess method, ELISA assay kit, and RAW 264.7 cells. The IC50 values of twig and unripe fruit extracts for AGS cells were 82.01 and 100.61 µg/mL, respectively. For HeLa cells, pawpaw twig extracts exhibited the strongest ability to inhibit cervical cancer cell growth (IC50 = 97.73 µg/mL). Analysis of the cell cycle phase distribution and expression of the apoptosis regulatory proteins BCL-2, BAX, caspase-3, and PARP showed that pawpaw twig, root, and unripe fruit extracts induced Sub G1 cell cycle arrest and apoptosis of AGS and HeLa cells. In addition, the twig, root, and unripe fruit extracts of pawpaw effectively inhibited the inflammatory makers NO, TNF-α, IL-6, and iNOS. Particularly, the twig, root, and unripe fruit extracts at concentrations of 50 µg/mL exhibited > 50% inhibition of TNF-α. CONCLUSIONS: These findings indicate that pawpaw extracts are natural therapeutic agents that may be used for the prevention and treatment of gastric and cervical cancers, and encourage further studies on the anti-inflammatory potential of the pawpaw tree.


Subject(s)
Anti-Inflammatory Agents/pharmacology , Asimina/chemistry , Fruit/chemistry , Plant Leaves/chemistry , Plant Roots/chemistry , Animals , Apoptosis/drug effects , Apoptosis Regulatory Proteins/metabolism , Cell Cycle Checkpoints/drug effects , Cell Proliferation/drug effects , HeLa Cells , Humans , Mice , Nitric Oxide/biosynthesis , RAW 264.7 Cells
4.
Int J Mol Sci ; 20(5)2019 Mar 06.
Article in English | MEDLINE | ID: mdl-30845749

ABSTRACT

Fomes fomentarius, an edible mushroom, is known to have anti-cancer, anti-inflammatory, and anti-diabetes effects. However, the underlying anti-cancer mechanism of F. fomentarius is unknown. To determine the molecular mechanism of the anti-cancer effects of F. fomentarius, various methods were used including fluorescence-activated cell sorting, Western blotting, migration, and crystal violet assays. F. fomentarius ethanol extract (FFE) decreased cell viability in six cancer cell lines (MDA-MB-231, MCF-7, A549, H460, DU145, and PC-3). FFE decreased the migration of MDA-MB-231 cells without causing cell toxicity. Furthermore, FFE attenuated the expression of matrix metalloproteinase-9 and phosphorylation of Akt as well as increased E-cadherin in MDA-MB-231 cells. FFE arrested the S and G2/M populations by inhibiting the expression of cell cycle regulatory proteins such as cyclin-dependent kinase 2, cyclin A/E, and S-phase kinase-associated protein 2. FFE increased the sub-G1 population and expression of cleaved caspase-9, -3, and cleaved poly adenosine diphosphate (ADP-ribose) polymerase at 72 h and suppressed B-cell lymphoma 2. Interestingly, FFE and AKT inhibitors showed similar effects in MDA-MB-231 cells. Additionally, FFE contained betulin which inhibited p-AKT in MDA-MB-231 cells. Our findings demonstrate that FFE inhibits cell motility and growth and induces apoptosis by inhibiting the phsphoinositide 3- kinase /AKT pathway and caspase activation.


Subject(s)
Biological Products/pharmacology , Breast Neoplasms/metabolism , Coriolaceae/chemistry , Ethanol/pharmacology , Proto-Oncogene Proteins c-akt/metabolism , Breast Neoplasms/drug therapy , Cell Line, Tumor , Cell Movement/drug effects , Cell Proliferation/drug effects , Cell Survival/drug effects , Female , Humans , MCF-7 Cells , Matrix Metalloproteinase 9/metabolism , Phosphorylation , Signal Transduction/drug effects
5.
BMC Complement Altern Med ; 18(1): 242, 2018 Aug 30.
Article in English | MEDLINE | ID: mdl-30165848

ABSTRACT

BACKGROUND: Rhus verniciflua Stokes is an Asian tree species that is used as a food supplement and traditional medicine in Korea. However, its use is restricted by its potential to cause allergy. Thus, allergen-free R. verniciflua extracts are currently being marketed as a functional health food in Korea. In the present study, three different allergen-free R. verniciflua extracts (DRVE, FRVE, and FFRVE) were produced by detoxification of R. verniciflua, and their properties and constituents were compared. METHODS: The main components and properties (antibacterial, antioxidant, anticancer, and hepatic lipogenesis inhibitory effects) of the three allergen-free extracts were compared. Moreover, the major phenolic constituents of R. verniciflua, including gallic acid, fustin, fisetin, and quercetin, were analyzed in the three extracts. RESULTS: DRVE was superior to the two other extracts with regard to antioxidant activity, while FRVE was superior with regard to antimicrobial activity and suppression of hepatic lipogenesis. FRVE exhibited lipid-lowering effects by lowering sterol regulatory element-binding protein 1 and triglyceride levels, and promoting the activation of peroxisome proliferator-activated receptor and AMP-activated protein kinase in an in vitro model of non-alcoholic fatty liver. CONCLUSIONS: Overall, our findings demonstrate various differences among the three extracts. This suggests that functional and bioactive compounds present in R. verniciflua could be altered by the detoxification process, and this property could be considered in the development of functional health foods in the future.


Subject(s)
Plant Extracts , Rhus/chemistry , Anti-Infective Agents/analysis , Anti-Infective Agents/chemistry , Anti-Infective Agents/pharmacology , Antioxidants/analysis , Antioxidants/chemistry , Antioxidants/pharmacology , Cell Line, Tumor , Cell Survival/drug effects , Fermentation , Flavonoids/analysis , Flavonoids/chemistry , Flavonols , Humans , Lipogenesis/drug effects , Models, Biological , Non-alcoholic Fatty Liver Disease , Phenols/analysis , Phenols/chemistry , Plant Extracts/analysis , Plant Extracts/chemistry , Plant Extracts/pharmacology
6.
J Food Sci ; 83(5): 1430-1435, 2018 May.
Article in English | MEDLINE | ID: mdl-29660776

ABSTRACT

Pawpaw (Asimina triloba [L.] Dunal) is widely cultivated in Korea for its fruit, which contains bioactive compounds, such as acetogenins. In this study, we investigated the acetogenin content and antiproliferative activity of pawpaw fruit pulp against various cancer cell lines and evaluated the relationship between these two variables at different maturation stages. Unripe fruit had higher antiproliferative activity than ripe fruit, and the activity level depended on acetogenin content. In addition, the presence of specific acetogenins was related to inhibition of certain cancer cell types. The unripe fruit methanol and ethanol extracts (URFM and URFE, respectively) that were rich in acetogenins strongly inhibited the growth of HT-1080, HeLa, and AGS cells by >50% at concentrations of less than 115 µg/mL. These findings indicate that URFM and URFE have therapeutic potential for the treatment of cancer, and our study establishes a basis for further mechanistic studies of the antiproliferative activity of pawpaw fruit. However, it is necessary to further study the anticancer activity of acetogenins from pawpaw fruit using in vivo activity approaches. PRACTICAL APPLICATION: Pawpaw (Asimina triloba) contains acetogenins that can inhibit the growth of cancer cells. In our study, we demonstrate that the antiproliferative activity is higher in unripe than in ripe fruit and depends on acetogenin content. Our results indicate that the extract of unripe pawpaw fruit has value not only as a functional food, but has therapeutic potential for the treatment of cancer as a naturally derived substance that may be less toxic than conventional chemotherapy drugs.


Subject(s)
Acetogenins/analysis , Asimina/chemistry , Cell Proliferation/drug effects , Fruit/chemistry , Antineoplastic Agents, Phytogenic/analysis , Antineoplastic Agents, Phytogenic/pharmacology , Cell Line, Tumor , HT29 Cells , HeLa Cells , Humans , MCF-7 Cells , Plant Extracts/analysis , Plant Extracts/pharmacology , Republic of Korea
7.
Int J Mol Sci ; 18(2)2017 Feb 04.
Article in English | MEDLINE | ID: mdl-28165392

ABSTRACT

Hypoxia enhances cancer development in a solid tumor. Hypoxia-inducible factor-1 α (HIF-1α) is a transcription factor that is dominantly expressed under hypoxia in solid tumor cells and is a key factor that regulates tumor. HIF-1α regulates several target genes involved in many aspects of cancer progression, including angiogenesis, metastasis, anti-apoptosis and cell proliferation as well as imparts resistance to cancer treatment. In this study, we assessed Crataegus Pinnatifida Bunge var. typical Schneider ethanol extract (CPE) for its anti-cancer effects in hypoxia-induced DU145 human prostate cancer cell line. CPE decreased the abundance of HIF-1α and sphingosine kinase-1 (SPHK-1) in hypoxia-induced prostate cancer DU145 cells. CPE decreased HIF-1α and SPHK-1 as well as SPHK-1 activity. Chlorogenic acid (CA) is one of four major compounds of CPE. Compared to CPE, CA significantly decreased the expression of HIF-1α and SPHK-1 as well as SPHK-1 activity in hypoxia-induced DU145 cells. Furthermore, CA decreased phosphorylation AKT and GSK-3ß, which are associated with HIF-1α stabilization and affected SPHK-1 in a concentration-dependent manner. We confirmed the mechanism of CA-induced inhibition of HIF-1α by SPHK-1 signaling pathway using SPHK-1 siRNA and SPHK inhibitor (SKI). CA decreased the secretion and cellular expression of VEGF, thus inhibiting hypoxia-induced angiogenesis. Treatment of DU145cells with SPHK1 siRNA and CA for 48 h decreased cancer cell growth, and the inhibitory action of SPHK siRNA and CA on cell growth was confirmed by decrease in the abundance of Proliferating cell nuclear antigen (PCNA).


Subject(s)
Chlorogenic Acid/pharmacology , Hypoxia-Inducible Factor 1, alpha Subunit/antagonists & inhibitors , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Hypoxia/metabolism , Phosphotransferases (Alcohol Group Acceptor)/metabolism , Cell Line, Tumor , Cell Proliferation/drug effects , Chlorogenic Acid/chemistry , Enzyme Activation/drug effects , Glycogen Synthase Kinase 3 beta/metabolism , Humans , Neovascularization, Pathologic/metabolism , Phosphorylation , Plant Extracts/chemistry , Plant Extracts/pharmacology , Protein Stability , Proto-Oncogene Proteins c-akt/metabolism
8.
BMC Cancer ; 16: 701, 2016 08 31.
Article in English | MEDLINE | ID: mdl-27581969

ABSTRACT

BACKGROUND: Hypoxia is a typical character of locally advanced solid tumours. The transcription factor hypoxia-inducible factor 1α (HIF-1α) is the main regulator under the hypoxic environment. HIF-1α regulates various genes to enhance tumour progression, angiogenesis, and metastasis. Sphingosine kinase 1 (SPHK-1) is a modulator of HIF-1α. METHODS: To investigate the molecular mechanisms of pristimerin in association with SPHK-1 pathways in hypoxic PC-3 cancer cells. Vascular endothelial growth factor (VEGF) production, cell cycles, and SPHK-1 activity were measured, and western blotting, an MTT assay, and an RNA interference assay were performed. RESULTS: Pristimerin inhibited HIF-1α accumulation in a concentration- and-time-dependent manner in hypoxic PC-3 cells. Pristimerin suppressed the expression of HIF-1α by inhibiting SPHK-1. Moreover, inhibiting SPHK-1 with a sphingosine kinase inhibitor enhanced the suppression of HIF-1α, phosphorylation AKT, and glycogen synthase kinase-3ß (GSK-3ß) by pristimerin under hypoxia. Furthermore, a reactive oxygen species (ROS) scavenger enhanced the inhibition of HIF-1α and SPHK-1 by pristimerin. CONCLUSION: Taken together, these findings suggest that pristimerin can exert an anti-cancer activity by inhibiting HIF-1α through the SPHK-1 pathway.


Subject(s)
Antineoplastic Agents/pharmacology , Hypoxia-Inducible Factor 1, alpha Subunit/drug effects , Phosphotransferases (Alcohol Group Acceptor)/drug effects , Prostatic Neoplasms/metabolism , Triterpenes/pharmacology , Blotting, Western , Cell Hypoxia/drug effects , Cell Line, Tumor , Gene Expression Regulation, Neoplastic/drug effects , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Male , Pentacyclic Triterpenes , Phosphotransferases (Alcohol Group Acceptor)/metabolism , Signal Transduction/drug effects
9.
Int J Mol Sci ; 17(7)2016 Jul 07.
Article in English | MEDLINE | ID: mdl-27399684

ABSTRACT

Lambertianic acid (LA) is known to have anti-allergic and antibacterial effects. However, the anticancer activities and mechanism of action of LA have not been investigated. Therefore, the anticancer effects and mechanism of LA are investigated in this study. LA decreased not only AR protein levels, but also cellular and secretory levels of PSA. Furthermore, LA inhibited nuclear translocation of the AR induced by mibolerone. LA suppressed cell proliferation by inducing G1 arrest, downregulating CDK4/6 and cyclin D1 and activating p53 and its downstream molecules, p21 and p27. LA induced apoptosis and the expression of related proteins, including cleaved caspase-9 and -3, c-PARP and BAX, and inhibited BCl-2. The role of AR in LA-induced apoptosis was assessed by using siRNA. Collectively, these findings suggest that LA exerts the anticancer effect by inhibiting AR and is a valuable therapeutic agent in prostate cancer treatment.


Subject(s)
Antineoplastic Agents/toxicity , Carboxylic Acids/toxicity , Cell Proliferation/drug effects , Naphthalenes/toxicity , Receptors, Androgen/metabolism , Apoptosis/drug effects , Caspase 3/metabolism , Caspase 9/metabolism , Cell Cycle Proteins/metabolism , Cell Line, Tumor , Cyclin D1/metabolism , Cyclin-Dependent Kinase 4/metabolism , Cyclin-Dependent Kinase 6/metabolism , Down-Regulation/drug effects , G1 Phase Cell Cycle Checkpoints/drug effects , Humans , Nandrolone/analogs & derivatives , Nandrolone/pharmacology , Prostate-Specific Antigen/metabolism , Proto-Oncogene Proteins c-bcl-2/metabolism , RNA Interference , RNA, Small Interfering/metabolism , Receptors, Androgen/chemistry , Receptors, Androgen/genetics , Tumor Suppressor Protein p53/metabolism , bcl-2-Associated X Protein/metabolism
10.
Nat Med ; 20(8): 954-960, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24997607

ABSTRACT

Functional screening for compounds that promote remyelination represents a major hurdle in the development of rational therapeutics for multiple sclerosis. Screening for remyelination is problematic, as myelination requires the presence of axons. Standard methods do not resolve cell-autonomous effects and are not suited for high-throughput formats. Here we describe a binary indicant for myelination using micropillar arrays (BIMA). Engineered with conical dimensions, micropillars permit resolution of the extent and length of membrane wrapping from a single two-dimensional image. Confocal imaging acquired from the base to the tip of the pillars allows for detection of concentric wrapping observed as 'rings' of myelin. The platform is formatted in 96-well plates, amenable to semiautomated random acquisition and automated detection and quantification. Upon screening 1,000 bioactive molecules, we identified a cluster of antimuscarinic compounds that enhance oligodendrocyte differentiation and remyelination. Our findings demonstrate a new high-throughput screening platform for potential regenerative therapeutics in multiple sclerosis.


Subject(s)
High-Throughput Screening Assays/methods , Multiple Sclerosis/drug therapy , Muscarinic Antagonists/isolation & purification , Nerve Fibers, Myelinated/drug effects , Animals , Cell Differentiation/drug effects , Cells, Cultured , Clemastine/pharmacology , Drug Evaluation, Preclinical/methods , Female , Histamine H1 Antagonists/pharmacology , Mice , Mice, Inbred C57BL , Mice, Transgenic , Muscarinic Antagonists/pharmacology , Nanostructures , Oligodendroglia/cytology , Oligodendroglia/drug effects , Oligodendroglia/physiology , Rats , Rats, Sprague-Dawley , Regeneration/drug effects
11.
Nat Protoc ; 8(4): 771-82, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23589937

ABSTRACT

Current methods for studying oligodendrocyte myelination using primary neurons are limited by the time, cost and reproducibility of myelination in vitro. Nanofibers with diameters of >0.4 µm fabricated from electrospinning of liquid polystyrene are suitable scaffolds for concentric membrane wrapping by oligodendrocytes. With the advent of aligned electrospinning technology, nanofibers can be rapidly fabricated, standardized, and configured into various densities and patterns as desired. Notably, the minimally permissive culture environment of fibers provides investigators with an opportunity to explore the autonomous oligodendrocyte cellular processes underlying differentiation and myelination. The simplicity of the system is conducive to monitoring oligodendrocyte proliferation, migration, differentiation and membrane wrapping in the absence of neuronal signals. Here we describe protocols for the fabrication and preparation of nanofibers aligned on glass coverslips for the study of membrane wrapping by rodent oligodendrocytes. The entire protocol can be completed within 2 weeks.


Subject(s)
Cell Culture Techniques , Myelin Sheath/metabolism , Nanofibers/chemistry , Animals , Cell Differentiation , Cell Movement , Cell Proliferation , Cells, Cultured , Mice , Models, Biological , Myelin Sheath/physiology , Nanofibers/ultrastructure , Oligodendroglia/cytology , Oligodendroglia/ultrastructure , Rats , Reproducibility of Results , Surface Properties , Tissue Scaffolds
12.
PLoS One ; 7(11): e48967, 2012.
Article in English | MEDLINE | ID: mdl-23145041

ABSTRACT

From a genetic screen for Drosophila melanogaster mutants with altered ethanol tolerance, we identified intolerant (intol), a novel allele of discs large 1 (dlg1). Dlg1 encodes Discs Large 1, a MAGUK (Membrane Associated Guanylate Kinase) family member that is the highly conserved homolog of mammalian PSD-95 and SAP97. The intol mutation disrupted specifically the expression of DlgS97, a SAP97 homolog, and one of two major protein isoforms encoded by dlg1 via alternative splicing. Expression of the major isoform, DlgA, a PSD-95 homolog, appeared unaffected. Ethanol tolerance in the intol mutant could be partially restored by transgenic expression of DlgS97, but not DlgA, in specific neurons of the fly's brain. Based on co-immunoprecipitation, DlgS97 forms a complex with N-methyl-D-aspartate (NMDA) receptors, a known target of ethanol. Consistent with these observations, flies expressing reduced levels of the essential NMDA receptor subunit dNR1 also showed reduced ethanol tolerance, as did mutants in the gene calcium/calmodulin-dependent protein kinase (caki), encoding the fly homolog of mammalian CASK, a known binding partner of DlgS97. Lastly, mice in which SAP97, the mammalian homolog of DlgS97, was conditionally deleted in adults failed to develop rapid tolerance to ethanol's sedative/hypnotic effects. We propose that DlgS97/SAP97 plays an important and conserved role in the development of tolerance to ethanol via NMDA receptor-mediated synaptic plasticity.


Subject(s)
Ethanol/toxicity , Guanylate Kinases/genetics , Membrane Proteins/genetics , Neurons/metabolism , Alleles , Alternative Splicing , Animals , Discs Large Homolog 1 Protein , Drosophila Proteins/genetics , Drosophila Proteins/metabolism , Drosophila melanogaster , Female , Guanylate Kinases/metabolism , Male , Membrane Proteins/metabolism , Mice , Mice, Inbred C57BL , Mutation/genetics , Protein Isoforms , Receptors, N-Methyl-D-Aspartate/genetics , Receptors, N-Methyl-D-Aspartate/metabolism , Repressor Proteins/genetics , Repressor Proteins/metabolism , Tumor Suppressor Proteins/genetics , Tumor Suppressor Proteins/metabolism
13.
Nat Methods ; 9(9): 917-22, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22796663

ABSTRACT

Current methods for studying central nervous system myelination necessitate permissive axonal substrates conducive to myelin wrapping by oligodendrocytes. We have developed a neuron-free culture system in which electron-spun nanofibers of varying sizes substitute for axons as a substrate for oligodendrocyte myelination, thereby allowing manipulation of the biophysical elements of axonal-oligodendroglial interactions. To investigate axonal regulation of myelination, this system effectively uncouples the role of molecular (inductive) cues from that of biophysical properties of the axon. We use this method to uncover the causation and sufficiency of fiber diameter in the initiation of concentric wrapping by rat oligodendrocytes. We also show that oligodendrocyte precursor cells display sensitivity to the biophysical properties of fiber diameter and initiate membrane ensheathment before differentiation. The use of nanofiber scaffolds will enable screening for potential therapeutic agents that promote oligodendrocyte differentiation and myelination and will also provide valuable insight into the processes involved in remyelination.


Subject(s)
Cell Culture Techniques/methods , Myelin Sheath/physiology , Nanofibers/chemistry , Nanotechnology/methods , Oligodendroglia/cytology , Animals , Cell Proliferation , Female , Male , Microscopy, Electron, Scanning , Polylysine/chemistry , Rats , Rats, Sprague-Dawley
14.
Proc Natl Acad Sci U S A ; 104(11): 4653-7, 2007 Mar 13.
Article in English | MEDLINE | ID: mdl-17360579

ABSTRACT

Habituation is a universal form of nonassociative learning that results in the devaluation of sensory inputs that have little information content. Although habituation is found throughout nature and has been studied in many organisms, the underlying molecular mechanisms remain poorly understood. We performed a forward genetic screen in Drosophila to search for mutations that modified habituation of an olfactory-mediated locomotor startle response, and we isolated a mutation in the glycogen synthase kinase-3 (GSK-3) homolog Shaggy. Decreases in Shaggy levels blunted habituation, whereas increases promoted habituation. Additionally, habituation acutely regulated Shaggy by an inhibitory phosphorylation mechanism, suggesting that a signal transduction pathway that regulates Shaggy is engaged during habituation. Although shaggy mutations also affected circadian rhythm period, this requirement was genetically separable from its role in habituation. Thus, shaggy functions in different neuronal circuits to regulate behavioral plasticity to an olfactory startle and circadian rhythmicity.


Subject(s)
Drosophila Proteins/physiology , Glycogen Synthase Kinase 3/physiology , Habituation, Psychophysiologic , Alleles , Animals , Behavior, Animal , Circadian Rhythm , Drosophila , Female , Glycogen Synthase Kinase 3/metabolism , Glycogen Synthase Kinase 3 beta , Male , Models, Genetic , Mutation , Phosphorylation , Signal Transduction , Smell
15.
J Biol Chem ; 277(48): 46730-5, 2002 Nov 29.
Article in English | MEDLINE | ID: mdl-12351654

ABSTRACT

Multiprotein complexes mediate static and dynamic functions to establish and maintain cell polarity in both epithelial cells and neurons. Membrane-associated guanylate kinase (MAGUK) proteins are thought to be scaffolding molecules in these processes and bind multiple proteins via their obligate postsynaptic density (PSD)-95/Disc Large/Zona Occludens-1, Src homology 3, and guanylate kinase-like domains. Subsets of MAGUK proteins have additional protein-protein interaction domains. An additional domain we identified in SAP97 called the MAGUK recruitment (MRE) domain binds the LIN-2,7 amino-terminal (L27N) domain of mLIN-2/CASK, a MAGUK known to bind mLIN-7. Here we show that SAP97 binds two other mLIN-7 binding MAGUK proteins. One of these MAGUK proteins, DLG3, coimmunoprecipitates with SAP97 in lysates from rat brain and transfected Madin-Darby canine kidney cells. This interaction requires the MRE domain of SAP97 and surprisingly, both the L27N and L27 carboxyl-terminal (L27C) domains of DLG3. We also demonstrate that SAP97 can interact with the MAGUK protein, DLG2, but not the highly related protein, PALS2. The ability of SAP97 to interact with multiple MAGUK proteins is likely to be important for the targeting of specific protein complexes in polarized cells.


Subject(s)
Nerve Tissue Proteins/metabolism , Adaptor Proteins, Signal Transducing , Animals , Cell Line , Discs Large Homolog 1 Protein , Dogs , Guanylate Kinases , Membrane Proteins , Mutagenesis, Site-Directed , Nerve Tissue Proteins/chemistry , Nerve Tissue Proteins/genetics , Nucleoside-Phosphate Kinase/metabolism , Protein Binding , Tumor Suppressor Proteins
16.
J Cell Biol ; 157(1): 161-72, 2002 Apr 01.
Article in English | MEDLINE | ID: mdl-11927608

ABSTRACT

Membrane-associated guanylate kinase (Maguk) proteins are scaffold proteins that contain PSD-95-Discs Large-zona occludens-1 (PDZ), Src homology 3, and guanylate kinase domains. A subset of Maguk proteins, such as mLin-2 and protein associated with Lin-7 (Pals)1, also contain two L27 domains: an L27C domain that binds mLin-7 and an L27N domain of unknown function. Here, we demonstrate that the L27N domain targets Pals1 to tight junctions by binding to a PDZ domain protein, Pals1-associated tight junction (PATJ) protein, via a unique Maguk recruitment domain. PATJ is a homologue of Drosophila Discs Lost, a protein that is crucial for epithelial polarity and that exists in a complex with the apical polarity determinant, Crumbs. PATJ and a human Crumbs homologue, CRB1, colocalize with Pals1 to tight junctions, and CRB1 interacts with PATJ albeit indirectly via binding the Pals1 PDZ domain. In agreement, we find that a Drosophila homologue of Pals1 participates in identical interactions with Drosophila Crumbs and Discs Lost. This Drosophila Pals1 homologue has been demonstrated recently to represent Stardust, a crucial polarity gene in Drosophila. Thus, our data identifies a new multiprotein complex that appears to be evolutionarily conserved and likely plays an important role in protein targeting and cell polarity.


Subject(s)
Carrier Proteins/metabolism , Eye Proteins/metabolism , Membrane Proteins/metabolism , Membrane Transport Proteins , Nerve Tissue Proteins , Nucleoside-Phosphate Kinase/metabolism , Tight Junctions/metabolism , Adaptor Proteins, Signal Transducing , Amino Acid Sequence , Animals , Carrier Proteins/chemistry , Carrier Proteins/genetics , Cells, Cultured , Conserved Sequence , Drosophila , Drosophila Proteins/genetics , Drosophila Proteins/metabolism , Eye Proteins/genetics , Guanylate Kinases , Humans , Insect Proteins/genetics , Kidney/cytology , Membrane Proteins/chemistry , Membrane Proteins/genetics , Molecular Sequence Data , Mutagenesis/physiology , Nucleoside-Phosphate Kinase/genetics , Protein Structure, Tertiary , Tight Junction Proteins , Vesicular Transport Proteins
17.
Mol Cell Biol ; 22(6): 1778-91, 2002 Mar.
Article in English | MEDLINE | ID: mdl-11865057

ABSTRACT

Mammalian Lin-2 (mLin-2)/CASK is a membrane-associated guanylate kinase (MAGUK) and contains multidomain modules that mediate protein-protein interactions important for the establishment and maintenance of neuronal and epithelial cell polarization. The importance of mLin-2/CASK in mammalian development is demonstrated by the fact that mutations in mLin-2/CASK or SAP97, another MAGUK protein, lead to cleft palate in mice. We recently identified a new protein-protein interaction domain, called the L27 domain, which is present twice in mLin-2/CASK. In this report, we further define the binding of the L27C domain of mLin-2/CASK to the L27 domain of mLin-7 and identify the binding partner for L27N of mLin-2/CASK. Biochemical analysis reveals that this L27N domain binds to the N terminus of SAP97, a region that was previously reported to be essential for the lateral membrane recruitment of SAP97 in epithelia. Our colocalization studies, using dominant-negative mLin-2/CASK, show that the association with mLin-2/CASK is crucial for lateral localization of SAP97 in MDCK cells. We also report the identification of a novel isoform of Discs Large, a Drosophila melanogaster orthologue of SAP97, which contains a region highly related to the SAP97 N terminus and which binds Camguk, a Drosophila orthologue of mLin-2/CASK. Our data identify evolutionarily conserved protein-protein interaction domains that link mLin-2/CASK to SAP97 and account for their common phenotype when mutated in mice.


Subject(s)
Calcium-Calmodulin-Dependent Protein Kinases , Epithelial Cells/metabolism , Nerve Tissue Proteins/metabolism , Nucleoside-Phosphate Kinase/metabolism , Adaptor Proteins, Signal Transducing , Animals , Cell Line , Cell Membrane/metabolism , Conserved Sequence , Discs Large Homolog 1 Protein , Dogs , Drosophila melanogaster , Epithelial Cells/cytology , Guanylate Kinases , Humans , Kidney/cytology , Kidney/metabolism , Macromolecular Substances , Membrane Proteins/metabolism , Molecular Sequence Data , Neurons/cytology , Neurons/metabolism , Precipitin Tests , Protein Binding/physiology , Protein Structure, Tertiary/physiology , Protein Transport/physiology , Sequence Homology, Amino Acid , Vesicular Transport Proteins
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