37 results on '"Kilinc, D."'
Search Results
2. Investigation of structural, morphological, electronic and photovoltaic properties of Co(II) complex with ligand
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Kilinc, D., Sahin, O., and Horoz, S.
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- 2018
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3. Production of forsterite from serpentine – Effects of magnesium chloride hexahydrate addition
- Author
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Emrullahoglu Abi, C.B., Gürel, S.B., Kılınç, D., and Emrullahoglu, Ö.F.
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- 2015
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4. Guillain–Barré syndrome after SARS‐CoV‐2 infection
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Kilinc, D., primary, van de Pasch, S., additional, Doets, A. Y., additional, Jacobs, B. C., additional, van Vliet, J., additional, and Garssen, M. P. J., additional
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- 2020
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5. The new genetic landscape of Alzheimer's disease: from amyloid cascade to genetically driven synaptic failure hypothesis?
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Dourlen P, Kilinc D, Malmanche N, Chapuis J, Lambert JC.
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- 2019
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6. Charge and topography patterned lithium niobate provides physical cues to fluidically isolated cortical axons
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Kilinc, D, Blasiak, A, Baghban, Mohammad Amin, Carville, N. C., Al-Adli, A., Al-Shammari, R. M., Rice, J. H., Lee, G. U., Gallo, Katia, Rodriguez, B. J., Kilinc, D, Blasiak, A, Baghban, Mohammad Amin, Carville, N. C., Al-Adli, A., Al-Shammari, R. M., Rice, J. H., Lee, G. U., Gallo, Katia, and Rodriguez, B. J.
- Abstract
In vitro devices that combine chemotactic and physical cues are needed for understanding how cells integrate different stimuli. We explored the suitability of lithium niobate (LiNbO3), a transparent ferroelectric material that can be patterned with electrical charge domains and micro/ nanotopography, as a neural substrate. On flat LiNbO3 z-surfaces with periodically alternating charge domains, cortical axons are partially aligned with domain boundaries. On submicron-deep etched trenches, neurites are aligned with the edges of the topographical features. Finally, we bonded a bicompartmental microfluidic chip to LiNbO3 surfaces patterned by etching, to create isolated axon microenvironments with predefined topographical cues. LiNbO3 is shown to be an emerging neuron culture substrate with tunable electrical and topographical properties that can be integrated with microfluidic devices, suitable for studying axon growth and guidance mechanisms under combined topographical/chemical stimuli., QC 20170406
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- 2017
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7. Charge and topography patterned lithium niobate provides physical cues to fluidically isolated cortical axons
- Author
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Kilinc, D., primary, Blasiak, A., additional, Baghban, M. A., additional, Carville, N. C., additional, Al-Adli, A., additional, Al-Shammari, R. M., additional, Rice, J. H., additional, Lee, G. U., additional, Gallo, K., additional, and Rodriguez, B. J., additional
- Published
- 2017
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8. Papillon-Léage and psaume syndrome patient with multiple dental and orofacial anomalies.
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Kilinc, D and Ozsarp, E
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- 2019
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9. A STUDY ON THE STRUCTURAL, OPTICAL AND PHOTOVOLTAIC PROPERTIES OF Fe(II) SCHIFF BASE COMPLEX WITH 5 AMINO-2,4-DICHLOROPHENOL-3,5-DITERTBUTHYSALISYLALDIMINE LIGAND.
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KILINC, D., SAHIN, O., and HOROZ, S.
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SCHIFF bases , *MONOCLINIC crystal system , *OPEN-circuit voltage , *INFRARED absorption , *OPTICAL properties , *CHARGE transfer - Abstract
In our present study, 5 amino-2,4-dichlorophenol-3,5-ditertbuthysalisylaldimine ligand was synthesized and we used this ligand to prepare its-Fe(II) complex with using the wet chemical method. The structural, optical and electronic properties of Fe(II) Schiff base complex with ligand were characterized using the x- ray diffraction (XRD), optical absorption and Fourier transform- infrared (FT-IR) measurements, respectively. The structure of Fe(II) Schiff base complex with ligand was determined as a monoclinic crystal system. Two absorption bands were observed in the UV-visible region. They are assigned to intraligand and charge transfer transitions, respectively. The FT-IR spectra of Fe(II) Schiff base complex with ligand are similar to the ligand spectra. Despite the similarity, a shift toward higher frequencies was observed in the vibration modes of azomethine groups. Furthermore, Fe(II) Schiff base complex was used as a photosensitizer on TiO2 film in a DSSC device. Thus, the effect of Fe(II) Schiff base complex on the efficiency of DSSC device was investigated and photovoltaic parameters such as power conversion efficiency (η), open circuit voltage (VOC) and short circuit current density (JSC) were determined. The obtained JSC and VOC value for samples is 3.75mA/cm² and 600 mV, respectively. The η % value was calculated as 0.80. Our result leads to obtain improved conversion efficiency of Fe(II) Schiff base complex with ligand based DSSC device. [ABSTRACT FROM AUTHOR]
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- 2019
10. INVESTIGATION OF PHOTOVOLTAIC PROPERTIES OF Al2O3 SUPPORTED Ni (II)-SCHIFF BASE COMPLEX SYNTHESIZED BY WET CHEMICAL METHOD.
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KILINC, D., SAHIN, O., and HOROZ, S.
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SCHIFF bases , *PHOTOVOLTAIC cells , *NICKEL , *X-ray diffraction , *ELECTROCHEMISTRY - Abstract
In our present study, 5-amino-2, 4-dichlorophenol-3,5-ditertbutylsalisylaldimine ligand, Ni (II)-Schiff Base complex and Al2O3 supported Ni (II)-Schiff Base complex were synthesized by wet chemical method. Current density (J)-voltage (V) measurement was performed to investigate the effect of Al2O3 support material on the photovoltaic properties of Ni (II) Schiff Base complex. The power conversion efficiencies (η%) for Ni (II)-Schiff Base and Al2O3 supported Ni (II)-Schiff Base complexes were calculated as 0,72 and 0.85, respectively. This result suggests that Al2O3 supported Ni (II)-Schiff Base complex with ligand which shows higher solar cell performance than pure Ni (II) Schiff based complex, can be used as a sensitizer in DSSC technology. Moreover, the structural, morphological and optical properties of Al2O3 supported Ni (II)-Schiff Base complex were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier Transform Infrared Spectroscopy (FT-IR) and optical absorption measurements, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2018
11. Micromagnet arrays for on-chip focusing, switching, and separation of superparamagnetic beads and single cells
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Rampini, S., primary, Kilinc, D., additional, Li, P., additional, Monteil, C., additional, Gandhi, D., additional, and Lee, G. U., additional
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- 2015
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12. In vitro study of the interaction of heregulin-functionalized magnetic–optical nanorods with MCF7 and MDA-MB-231 cells.
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Lesniak, A., Kilinc, D., Rashdan, Suad A., von Kriegsheim, A., Ashall, B., Zerulla, D., Kolch, W., and Lee, G. U.
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Multifunctional nanoparticles that actively target specific cells are promising tools for cancer diagnosis and therapy. In this article we review the synthesis and surface chemistry of Fe–Au nanorods and their characterization using microscopy. The diameter of the rods used in this study was selected to be 150–200 nm so that they did not enter the cells. The 80 nm-long Au tips of the nanorods were functionalized with heregulin (HRG), and the micron-long Fe portion was coated with a poly(ethylene glycol) monolayer to minimize non-specific interactions. Nanorods functionalized with HRG were found to preferentially bind to MCF7 cells that express high levels of the receptor tyrosine-protein kinase ErbB2/3. Magnetic tweezers measurements were used to characterize the kinetic properties of the bond between the HRG on the rods and ErbB2/3 on the surface of the cells. The strong magnetization of Fe–Au nanorods makes them excellent candidates for in-vitro and in-vivo imaging, and magnetic therapeutic applications targeting cancer cells in circulation. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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13. Papillon-Léage and psaume syndrome patient with multiple dental and orofacial anomalies
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Delal Dara Kılınç, Ecem Özsarp, Kilinc, D. D., Ozsarp, E. Istanbul Medipol Univ, Fac Dent, Dept Orthodont, Istanbul, Turkey, and Kilinc, Delal Dara -- 0000-0001-9009-6218
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Dental anomalies ,medicine.medical_specialty ,Syndrome type ,Adolescent ,Tooth Movement Techniques ,business.industry ,Tooth, Impacted ,Oral-Facial-Digital Syndrome Type I ,General Medicine ,Malocclusion, Angle Class I ,Orofaciodigital Syndromes ,Oral cavity ,Syndrome patient ,Dermatology ,Cleft Palate ,stomatognathic diseases ,Visceral organ ,Maxilla ,Medicine ,Humans ,Abnormalities, Multiple ,Female ,Papillon-Leage-Psaume syndrome ,business ,Papillon-Leage Psaume Syndrome - Abstract
WOS: 000471973600021 PubMed ID: 31187776 Papillon-Leage-Psaume Syndrome, also known as oral-facial-digital syndrome (OFDS) type I, describes a group of neurodevelopmental disorders that are characterized by anomalies of the oral cavity, facial features, and the digits. Central nervous system (CNS) anomalies and visceral organ abnormalities such as kidney, pancreas, and ovarian cysts can also be seen in these patients. Among 13 potential types, female-inherited OFDS type I is the most common and it has been reported to be lethal in males. After the identification of the genetic relation of OFDS in 2001, it is now known that, except X-linked OFDS Type I and VIII, generally all types of OFDSs are autosomal recessive. The dentist's knowledge about the syndrome can reduce the development of physical and dental anomalies by facilitating early diagnosis. This article presents a patient with Papillon-Leage-Psaume Syndrome (Oral-Facial-Digital Syndrome Type I).
- Published
- 2019
14. Nifuroxazide rescues the deleterious effects due to CHCHD10-associated MICOS defects in disease models.
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Ropert B, Bannwarth S, Genin EC, Vaillant-Beuchot L, Lacas-Gervais S, Hounoum BM, Bernardin A, Dinh N, Mauri-Crouzet A, D'Elia MA, Augé G, Lespinasse F, Di Giorgio A, Meira W, Bonnefoy N, Monassier L, Schiff M, Sago L, Kilinc D, Brau F, Redeker V, Bohl D, Tribouillard-Tanvier D, Procaccio V, Azoulay S, Ricci JE, Delahodde A, and Paquis-Flucklinger V
- Abstract
The identification of a point mutation (p.Ser59Leu) in the CHCHD10 gene was the first genetic evidence that mitochondrial dysfunction can trigger motor neuron disease. Since then, we have shown that this mutation leads to the disorganization of the MItochondrial contact site and Cristae Organizing System (MICOS) complex that maintains the mitochondrial cristae structure. Here, we generated yeast mutant strains mimicking MICOS instability and used them to test the ability of more than 1600 compounds from 2 repurposed libraries to rescue the growth defect of those cells. Among the hits identified, we selected nifuroxazide, a broad-spectrum antibacterial molecule. We show that nifuroxazide rescues mitochondrial network fragmentation and cristae abnormalities in CHCHD10S59L/+ patient fibroblasts. This molecule also decreases caspase-dependent death of human CHCHD10S59L/+ iPSC-derived motor neurons. Its benefits involve KIF5B-mediated mitochondrial transport enhancement, evidenced by increased axonal movement and syntaphilin degradation in patient-derived motor neurons. Our findings strengthen the MICOS-mitochondrial transport connection. Nifuroxazide and analogues emerge as potential therapeutics for MICOS-related disorders like motor neuron disease. Its impact on syntaphilin hints at broader neurological disorder applicability for nifuroxazide., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)
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- 2024
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15. The Alzheimer's disease risk gene BIN1 regulates activity-dependent gene expression in human-induced glutamatergic neurons.
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Saha O, Melo de Farias AR, Pelletier A, Siedlecki-Wullich D, Landeira BS, Gadaut J, Carrier A, Vreulx AC, Guyot K, Shen Y, Bonnefond A, Amouyel P, Tcw J, Kilinc D, Queiroz CM, Delahaye F, Lambert JC, and Costa MR
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- Humans, Glutamic Acid metabolism, Calcium metabolism, Calcium Channels, L-Type metabolism, Calcium Channels, L-Type genetics, Brain metabolism, Gene Expression genetics, Nuclear Proteins genetics, Nuclear Proteins metabolism, Alzheimer Disease metabolism, Alzheimer Disease genetics, Induced Pluripotent Stem Cells metabolism, Neurons metabolism, Adaptor Proteins, Signal Transducing genetics, Adaptor Proteins, Signal Transducing metabolism, Tumor Suppressor Proteins genetics, Tumor Suppressor Proteins metabolism
- Abstract
Bridging Integrator 1 (BIN1) is the second most important Alzheimer's disease (AD) risk gene, but its physiological roles in neurons and its contribution to brain pathology remain largely elusive. In this work, we show that BIN1 plays a critical role in the regulation of calcium homeostasis, electrical activity, and gene expression of glutamatergic neurons. Using single-cell RNA-sequencing on cerebral organoids generated from isogenic BIN1 wild type (WT), heterozygous (HET) and homozygous knockout (KO) human-induced pluripotent stem cells (hiPSCs), we show that BIN1 is mainly expressed by oligodendrocytes and glutamatergic neurons, like in the human brain. Both BIN1 HET and KO cerebral organoids show specific transcriptional alterations, mainly associated with ion transport and synapses in glutamatergic neurons. We then demonstrate that BIN1 cell-autonomously regulates gene expression in glutamatergic neurons by using a novel protocol to generate pure culture of hiPSC-derived induced neurons (hiNs). Using this system, we also show that BIN1 plays a key role in the regulation of neuronal calcium transients and electrical activity via its interaction with the L-type voltage-gated calcium channel Cav
1.2 . BIN1 KO hiNs show reduced activity-dependent internalization and higher Cav1.2 expression compared to WT hiNs. Pharmacological blocking of this channel with clinically relevant doses of nifedipine, a calcium channel blocker, partly rescues electrical and gene expression alterations in BIN1 KO glutamatergic neurons. Further, we show that transcriptional alterations in BIN1 KO hiNs that affect biological processes related to calcium homeostasis are also present in glutamatergic neurons of the human brain at late stages of AD pathology. Together, these findings suggest that BIN1-dependent alterations in neuronal properties could contribute to AD pathophysiology and that treatment with low doses of clinically approved calcium blockers should be considered as an option to slow disease-onset and progression., (© 2024. The Author(s).)- Published
- 2024
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16. Neuronal A2A receptor exacerbates synapse loss and memory deficits in APP/PS1 mice.
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Gomez-Murcia V, Launay A, Carvalho K, Burgard A, Meriaux C, Caillierez R, Eddarkaoui S, Kilinc D, Siedlecki-Wullich D, Besegher M, Bégard S, Thiroux B, Jung M, Nebie O, Wisztorski M, Déglon N, Montmasson C, Bemelmans AP, Hamdane M, Lebouvier T, Vieau D, Fournier I, Buee L, Lévi S, Lopes LV, Boutillier AL, Faivre E, and Blum D
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- Animals, Mice, Hippocampus metabolism, Hippocampus pathology, Presenilin-1 genetics, Disease Models, Animal, Plaque, Amyloid pathology, Plaque, Amyloid metabolism, Male, Mice, Inbred C57BL, Memory Disorders metabolism, Memory Disorders genetics, Memory Disorders pathology, Receptor, Adenosine A2A metabolism, Receptor, Adenosine A2A genetics, Synapses metabolism, Synapses pathology, Amyloid beta-Protein Precursor genetics, Amyloid beta-Protein Precursor metabolism, Mice, Transgenic, Neurons metabolism, Neurons pathology, Alzheimer Disease metabolism, Alzheimer Disease pathology, Alzheimer Disease genetics
- Abstract
Early pathological upregulation of adenosine A2A receptors (A2ARs), one of the caffeine targets, by neurons is thought to be involved in the development of synaptic and memory deficits in Alzheimer's disease (AD) but mechanisms remain ill-defined. To tackle this question, we promoted a neuronal upregulation of A2AR in the hippocampus of APP/PS1 mice developing AD-like amyloidogenesis. Our findings revealed that the early upregulation of A2AR in the presence of an ongoing amyloid pathology exacerbates memory impairments of APP/PS1 mice. These behavioural changes were not linked to major change in the development of amyloid pathology but rather associated with increased phosphorylated tau at neuritic plaques. Moreover, proteomic and transcriptomic analyses coupled with quantitative immunofluorescence studies indicated that neuronal upregulation of the receptor promoted both neuronal and non-neuronal autonomous alterations, i.e. enhanced neuroinflammatory response but also loss of excitatory synapses and impaired neuronal mitochondrial function, presumably accounting for the detrimental effect on memory. Overall, our results provide compelling evidence that neuronal A2AR dysfunction, as seen in the brain of patients, contributes to amyloid-related pathogenesis and underscores the potential of A2AR as a relevant therapeutic target for mitigating cognitive impairments in this neurodegenerative disorder., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain.)
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- 2024
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17. Integration of Microfluidic Devices with Microelectrode Arrays to Functionally Assay Amyloid-β-Induced Synaptotoxicity.
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Lefebvre C, Vreulx AC, Dumortier C, Bégard S, Gelle C, Siedlecki-Wullich D, Colin M, Kilinc D, and Halliez S
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- Mice, Animals, Humans, Microelectrodes, Amyloid beta-Peptides genetics, Amyloid beta-Peptides chemistry, Amyloid beta-Peptides metabolism, Lab-On-A-Chip Devices, Neurodegenerative Diseases, Alzheimer Disease genetics, Alzheimer Disease metabolism, Alzheimer Disease pathology
- Abstract
Alzheimer's disease (AD) is a neurodegenerative disease and the most frequent cause of dementia. It is characterized by the accumulation in the brain of two pathological protein aggregates: amyloid-β peptides (Aβ) and abnormally phosphorylated tau. The progressive cognitive decline observed in patients strongly correlates with the synaptic loss. Many lines of evidence suggest that soluble forms of Aβ accumulate into the brain where they cause synapse degeneration. Stopping their spreading and/or targeting the pathophysiological mechanisms leading to synaptic loss would logically be beneficial for the patients. However, we are still far from understanding these processes. Our objective was therefore to develop a versatile model to assay and study Aβ-induced synaptotoxicity. We integrated a microfluidic device that physically isolates synapses from presynaptic and postsynaptic neurons with a microelectrode array. We seeded mouse primary cortical cells in the presynaptic and postsynaptic chambers. After functional synapses have formed in the synaptic chamber, we exposed them to concentrated conditioned media from cell lines overexpressing the wild-type or mutated amyloid precursor protein and thus secreting different levels of Aβ. We recorded the neuronal activity before and after exposition to Aβ and quantified Aβ's effects on the connectivity between presynaptic and postsynaptic neurons. We observed that the application of Aβ on the synapses for 48 h strongly decreased the interchamber connectivity without significantly affecting the neuronal activity in the presynaptic or postsynaptic chambers. Thus, through this model, we are able to functionally assay the impact of Aβ peptides (or other molecules) on synaptic connectivity and to use the latter as a proxy to study Aβ-induced synaptotoxicity. Moreover, since the presynaptic, postsynaptic, and synaptic chambers can be individually targeted, our assay provides a powerful tool to evaluate the involvement of candidate genes in synaptic vulnerability and/or test therapeutic strategies for AD.
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- 2024
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18. High-Content Screening of Synaptic Density Modulators in Primary Neuronal Cultures.
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Coulon A, Siedlecki-Wullich D, Najdek C, Gelle C, Ayral AM, Demiautte F, Lambert E, Vandeputte A, Brodin P, Mendes T, Lambert JC, Kilinc D, Dumont J, and Chapuis J
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- Animals, Rats, Automation, Data Analysis, Neurons, RNA, Small Interfering, Bone Plates, Culture
- Abstract
The synapse, which represents the structural and functional basis of neuronal communication, is one of the first elements affected in several neurodegenerative diseases. To better understand the potential role of gene expression in synapse loss, we developed an original high-content screening (HCS) model capable of quantitatively assessing the impact of gene silencing on synaptic density. Our approach is based on a model of primary neuronal cultures (PNCs) from the neonatal rat hippocampus, whose mature synapses are visualized by the relative localization of the presynaptic protein Synaptophysin with the postsynaptic protein Homer1. The heterogeneity of PNCs and the small sizes of the synaptic structures pose technical challenges associated with the level of automation necessary for HCS studies. We overcame these technical challenges, automated the processes of image analysis and data analysis, and carried out tests under real-world conditions to demonstrate the robustness of the model developed. In this article, we describe the screening of a custom library of 198 shRNAs in PNCs in the 384-well plate format. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Culture of primary hippocampal rat neurons in 384-well plates Basic Protocol 2: Lentiviral shRNA transduction of primary neuronal culture in 384-well plates Basic Protocol 3: Immunostaining of the neuronal network and synaptic markers in 384-well plates Basic Protocol 4: Image acquisition using a high-throughput reader Basic Protocol 5: Image segmentation and analysis Basic Protocol 6: Synaptic density analysis., (© 2023 The Authors. Current Protocols published by Wiley Periodicals LLC.)
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- 2023
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19. PROTOCOL: Are tools that assess risk of violent radicalization fit for purpose? A systematic review.
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Hassan G, Brouillette-Alarie S, Ousman S, Madriaza P, Varela W, Danis E, Kilinc D, Pickup D, and Borokhovski E
- Abstract
This is the protocol for a Campbell systematic review. The main objective of this project is to gather, critically appraise, and synthesize evidence about the appropriateness and utility of tools used to assess the risk of violent radicalization., (© 2022 The Authors. Campbell Systematic Reviews published by John Wiley & Sons Ltd on behalf of The Campbell Collaboration.)
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- 2022
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20. Correction to: Alzheimer's genetic risk factor FERMT2 (Kindlin-2) controls axonal growth and synaptic plasticity in an APP-dependent manner.
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Eysert F, Coulon A, Boscher E, Vreulx AC, Flaig A, Mendes T, Hughes S, Grenier-Boley B, Hanoulle X, Demiautte F, Bauer C, Marttinen M, Takalo M, Amouyel P, Desai S, Pike I, Hiltunen M, Chécler F, Farinelli M, Delay C, Malmanche N, Hébert SS, Dumont J, Kilinc D, Lambert JC, and Chapuis J
- Published
- 2021
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21. Alzheimer's genetic risk factor FERMT2 (Kindlin-2) controls axonal growth and synaptic plasticity in an APP-dependent manner.
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Eysert F, Coulon A, Boscher E, Vreulx AC, Flaig A, Mendes T, Hughes S, Grenier-Boley B, Hanoulle X, Demiautte F, Bauer C, Marttinen M, Takalo M, Amouyel P, Desai S, Pike I, Hiltunen M, Chécler F, Farinelli M, Delay C, Malmanche N, Hébert SS, Dumont J, Kilinc D, Lambert JC, and Chapuis J
- Subjects
- Amyloid beta-Protein Precursor genetics, Humans, Membrane Proteins, Neoplasm Proteins, Neuronal Plasticity genetics, Neurons, Risk Factors, Alzheimer Disease genetics
- Abstract
Although APP metabolism is being intensively investigated, a large fraction of its modulators is yet to be characterized. In this context, we combined two genome-wide high-content screenings to assess the functional impact of miRNAs and genes on APP metabolism and the signaling pathways involved. This approach highlighted the involvement of FERMT2 (or Kindlin-2), a genetic risk factor of Alzheimer's disease (AD), as a potential key modulator of axon guidance, a neuronal process that depends on the regulation of APP metabolism. We found that FERMT2 directly interacts with APP to modulate its metabolism, and that FERMT2 underexpression impacts axonal growth, synaptic connectivity, and long-term potentiation in an APP-dependent manner. Last, the rs7143400-T allele, which is associated with an increased AD risk and localized within the 3'UTR of FERMT2, induced a downregulation of FERMT2 expression through binding of miR-4504 among others. This miRNA is mainly expressed in neurons and significantly overexpressed in AD brains compared to controls. Altogether, our data provide strong evidence for a detrimental effect of FERMT2 underexpression in neurons and insight into how this may influence AD pathogenesis., (© 2020. The Author(s).)
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- 2021
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22. Adherence to the European Society of Cardiology/European Society of Anaesthesiology recommendations on preoperative cardiac testing and association with positive results and cardiac events: a cohort study.
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Lurati Buse GAL, Puelacher C, Gualandro DM, Kilinc D, Glarner N, Hidvegi R, Bolliger D, Arslani K, Lampart A, Steiner LA, Kindler C, Wolff T, Mujagic E, Guerke L, and Mueller C
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- Algorithms, Clinical Decision-Making, Decision Support Techniques, Heart Diseases etiology, Heart Diseases mortality, Heart Diseases prevention & control, Humans, Predictive Value of Tests, Risk Assessment, Risk Factors, Surgical Procedures, Operative mortality, Treatment Outcome, Anesthesiology standards, Diagnostic Techniques, Cardiovascular standards, Guideline Adherence standards, Heart Diseases diagnosis, Practice Guidelines as Topic standards, Preoperative Care standards, Surgical Procedures, Operative adverse effects
- Abstract
Background: European Society of Cardiology/European Society of Anaesthesiology (ESC/ESA) guidelines inform cardiac workup before noncardiac surgery based on an algorithm. Our primary hypotheses were that there would be associations between (i) the groups stratified according to the algorithms and major adverse cardiac events (MACE), and (ii) over- and underuse of cardiac testing and MACE., Methods: This is a secondary analysis of a multicentre prospective cohort. Major adverse cardiac events were a composite of cardiac death, myocardial infarction, acute heart failure, and life-threatening arrhythmia at 30 days. For each cardiac test, pathological findings were defined a priori. We used multivariable logistic regression to measure associations., Results: We registered 359 MACE at 30 days amongst 6976 patients; classification in a higher-risk group using the ESC/ESA algorithm was associated with 30-day MACE; however, discrimination of the ESC/ESA algorithms for 30-day MACE was modest; area under the curve 0.64 (95% confidence interval: 0.61-0.67). After adjustment for sex, age, and ASA physical status, discrimination was 0.72 (0.70-0.75). Overuse or underuse of cardiac tests were not consistently associated with MACE. There was no independent association between test recommendation class and pathological findings (P=0.14 for stress imaging; P=0.35 for transthoracic echocardiography; P=0.52 for coronary angiography)., Conclusions: Discrimination for MACE using the ESC/ESA guidelines algorithms was limited. Overuse or underuse of cardiac tests was not consistently associated with cardiovascular events. The recommendation class of preoperative cardiac tests did not influence their yield., Clinical Trial Registration: NCT02573532., (Copyright © 2021 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2021
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23. Pyk2 overexpression in postsynaptic neurons blocks amyloid β 1-42 -induced synaptotoxicity in microfluidic co-cultures.
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Kilinc D, Vreulx AC, Mendes T, Flaig A, Marques-Coelho D, Verschoore M, Demiautte F, Amouyel P, Eysert F, Dourlen P, Chapuis J, Costa MR, Malmanche N, Checler F, and Lambert JC
- Abstract
Recent meta-analyses of genome-wide association studies identified a number of genetic risk factors of Alzheimer's disease; however, little is known about the mechanisms by which they contribute to the pathological process. As synapse loss is observed at the earliest stage of Alzheimer's disease, deciphering the impact of Alzheimer's risk genes on synapse formation and maintenance is of great interest. In this article, we report a microfluidic co-culture device that physically isolates synapses from pre- and postsynaptic neurons and chronically exposes them to toxic amyloid β peptides secreted by model cell lines overexpressing wild-type or mutated (V717I) amyloid precursor protein. Co-culture with cells overexpressing mutated amyloid precursor protein exposed the synapses of primary hippocampal neurons to amyloid β
1-42 molecules at nanomolar concentrations and induced a significant decrease in synaptic connectivity, as evidenced by distance-based assignment of postsynaptic puncta to presynaptic puncta. Treating the cells with antibodies that target different forms of amyloid β suggested that low molecular weight oligomers are the likely culprit. As proof of concept, we demonstrate that overexpression of protein tyrosine kinase 2 beta-an Alzheimer's disease genetic risk factor involved in synaptic plasticity and shown to decrease in Alzheimer's disease brains at gene expression and protein levels-selectively in postsynaptic neurons is protective against amyloid β1-42 -induced synaptotoxicity. In summary, our lab-on-a-chip device provides a physiologically relevant model of Alzheimer's disease-related synaptotoxicity, optimal for assessing the impact of risk genes in pre- and postsynaptic compartments., (© The Author(s) (2020). Published by Oxford University Press on behalf of the Guarantors of Brain.)- Published
- 2020
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24. Using operative features to identify surgical complexity: a case in breast surgery practice.
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Kilinc D, Shahraki N, Gel ES, Degnim AC, Hoskin T, Sir MY, and Pasupathy KS
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- Databases, Factual, Humans, Retrospective Studies, Workload, Breast Neoplasms, Surgeons
- Abstract
Increasing workload is one of the main problems that surgical practices face. This increase is not only due to the increasing demand volume but also due to increasing case complexity. This raises the question on how to measure and predict the complexity to address this issue. Predicting surgical duration is critical to parametrize surgical complexity, improve surgeon satisfaction by avoiding unexpected overtime, and improve operation room utilization. Our objective is to utilize the historical data on surgical operations to obtain complexity groups and use this groups to improve practice.Our study first leverages expert opinion on the surgical complexity to identify surgical groups. Then, we use a tree-based method on a large retrospective dataset to identify similar complexity groups by utilizing the surgical features and using surgical duration as a response variable. After obtaining the surgical groups by using two methods, we statistically compare expert-based grouping with the data-based grouping. This comparison shows that a tree-based method can provide complexity groups similar to the ones generated by an expert by using features that are available at the time of surgical listing. These results suggest that one can take advantage of available data to provide surgical duration predictions that are data-driven, evidence-based, and practically relevant.
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- 2020
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25. High-Content Screening for Protein-Protein Interaction Modulators Using Proximity Ligation Assay in Primary Neurons.
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Mendes T, Herledan A, Leroux F, Deprez B, Lambert JC, and Kilinc D
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- Algorithms, Animals, Problem Solving, Rats, Image Processing, Computer-Assisted methods, Neurons pathology, Protein Interaction Mapping methods
- Abstract
The proximity ligation assay (PLA) allows the detection and subcellular localization of protein-protein interactions with high specificity. We recently developed a high-content screening model based on primary hippocampal neurons cultured in 384-well plates and screened a library of ∼1100 compounds using a PLA between tau and bridging integrator 1, a genetic risk factor for Alzheimer's disease. We developed image-segmentation and spot-detection algorithms to delineate PLA signals in the axonal network, but not in cell bodies, from confocal images acquired via a high-throughput microscope. To compare data generated from different plates and through different experiments, we developed a computational routine to optimize the image analysis parameters for each plate and devised a range of quality-control measures to ultimately identify compounds that consistently increase or decrease our read-out. We provide the following protocols. © 2019 by John Wiley & Sons, Inc. Basic Protocol 1: Routine culture of rat postnatal hippocampal neurons in 384-well plates Basic Protocol 2: Compound incubation using the high-content screening platform Support Protocol 1: Preparation of intermediate plates for compound screening Support Protocol 2: Preparation of intermediate plates for hit validation (dose-response curves) Basic Protocol 3: Proximity ligation assay in 384-well plates Basic Protocol 4: Image acquisition and analysis Support Protocol 3: Optimization of analysis parameters Basic Protocol 5: Identification of hits Basic Protocol 6: Validation of hits based on dose-response curves., (© 2019 John Wiley & Sons, Inc.)
- Published
- 2020
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26. BIN1 recovers tauopathy-induced long-term memory deficits in mice and interacts with Tau through Thr 348 phosphorylation.
- Author
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Sartori M, Mendes T, Desai S, Lasorsa A, Herledan A, Malmanche N, Mäkinen P, Marttinen M, Malki I, Chapuis J, Flaig A, Vreulx AC, Ciancia M, Amouyel P, Leroux F, Déprez B, Cantrelle FX, Maréchal D, Pradier L, Hiltunen M, Landrieu I, Kilinc D, Herault Y, Laporte J, and Lambert JC
- Subjects
- Adaptor Proteins, Signal Transducing genetics, Alzheimer Disease genetics, Alzheimer Disease metabolism, Alzheimer Disease pathology, Animals, Brain metabolism, Brain pathology, Memory Disorders genetics, Memory Disorders pathology, Mice, Mice, Transgenic, Nerve Tissue Proteins genetics, Neurons metabolism, Neurons pathology, Phosphorylation, Spatial Memory physiology, Tauopathies genetics, Tauopathies pathology, Tumor Suppressor Proteins genetics, Adaptor Proteins, Signal Transducing metabolism, Memory Disorders metabolism, Memory, Long-Term physiology, Nerve Tissue Proteins metabolism, Tauopathies metabolism, Tumor Suppressor Proteins metabolism, tau Proteins metabolism
- Abstract
The bridging integrator 1 gene (BIN1) is a major genetic risk factor for Alzheimer's disease (AD). In this report, we investigated how BIN1-dependent pathophysiological processes might be associated with Tau. We first generated a cohort of control and transgenic mice either overexpressing human MAPT (TgMAPT) or both human MAPT and BIN1 (TgMAPT;TgBIN1), which we followed-up from 3 to 15 months. In TgMAPT;TgBIN1 mice short-term memory deficits appeared earlier than in TgMAPT mice; however-unlike TgMAPT mice-TgMAPT;TgBIN1 mice did not exhibit any long-term or spatial memory deficits for at least 15 months. After killing the cohort at 18 months, immunohistochemistry revealed that BIN1 overexpression prevents both Tau mislocalization and somatic inclusion in the hippocampus, where an increase in BIN1-Tau interaction was also observed. We then sought mechanisms controlling the BIN1-Tau interaction. We developed a high-content screening approach to characterize modulators of the BIN1-Tau interaction in an agnostic way (1,126 compounds targeting multiple pathways), and we identified-among others-an inhibitor of calcineurin, a Ser/Thr phosphatase. We determined that calcineurin dephosphorylates BIN1 on a cyclin-dependent kinase phosphorylation site at T348, promoting the open conformation of the neuronal BIN1 isoform. Phosphorylation of this site increases the availability of the BIN1 SH3 domain for Tau interaction, as demonstrated by nuclear magnetic resonance experiments and in primary neurons. Finally, we observed that although the levels of the neuronal BIN1 isoform were unchanged in AD brains, phospho-BIN1(T348):BIN1 ratio was increased, suggesting a compensatory mechanism. In conclusion, our data support the idea that BIN1 modulates the AD risk through an intricate regulation of its interaction with Tau. Alteration in BIN1 expression or activity may disrupt this regulatory balance with Tau and have direct effects on learning and memory.
- Published
- 2019
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27. Rapid Growth Cone Uptake and Dynein-Mediated Axonal Retrograde Transport of Negatively Charged Nanoparticles in Neurons Is Dependent on Size and Cell Type.
- Author
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Lesniak A, Kilinc D, Blasiak A, Galea G, Simpson JC, and Lee GU
- Subjects
- Animals, Cell Line, Dyneins metabolism, Lysosomes metabolism, Mice, Microfluidics, Neurons metabolism, Polystyrenes chemistry, Axonal Transport physiology, Axons metabolism, Nanoparticles chemistry
- Abstract
Nanoparticles (NPs) are now used in numerous technologies and serve as carriers for several new classes of therapeutics. Studies of the distribution of NPs in vivo demonstrate that they can be transported through biological barriers and are concentrated in specific tissues. Here, transport behavior, and final destination of polystyrene NPs are reported in primary mouse cortical neurons and SH-SY5Y cells, cultured in two-compartmental microfluidic devices. In both cell types, negative polystyrene NPs (PS(-)) smaller than 100 nm are taken up by the axons, undergo axonal retrograde transport, and accumulate in the somata. Examination of NP transport reveals different transport mechanisms depending on the cell type, particle charge, and particle internalization by the lysosomes. In cortical neurons, PS(-) inside lysosomes and 40 nm positive polystyrene NPs undergo slow axonal transport, whereas PS(-) outside lysosomes undergo fast axonal transport. Inhibition of dynein in cortical neurons decreases the transport velocity and cause a dose-dependent reduction in the number of accumulated PS(-), suggesting that the fast axonal transport is dynein mediated. These results show that the axonal retrograde transport of NPs depends on the endosomal pathway taken and establishes a means for screening nanoparticle-based therapeutics for diseases that involve neurons., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2019
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28. The Emerging Role of Mechanics in Synapse Formation and Plasticity.
- Author
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Kilinc D
- Abstract
The regulation of synaptic strength forms the basis of learning and memory, and is a key factor in understanding neuropathological processes that lead to cognitive decline and dementia. While the mechanical aspects of neuronal development, particularly during axon growth and guidance, have been extensively studied, relatively little is known about the mechanical aspects of synapse formation and plasticity. It is established that a filamentous actin network with complex spatiotemporal behavior controls the dendritic spine shape and size, which is thought to be crucial for activity-dependent synapse plasticity. Accordingly, a number of actin binding proteins have been identified as regulators of synapse plasticity. On the other hand, a number of cell adhesion molecules (CAMs) are found in synapses, some of which form transsynaptic bonds to align the presynaptic active zone (PAZ) with the postsynaptic density (PSD). Considering that these CAMs are key components of cellular mechanotransduction, two critical questions emerge: (i) are synapses mechanically regulated? and (ii) does disrupting the transsynaptic force balance lead to (or exacerbate) synaptic failure? In this mini review article, I will highlight the mechanical aspects of synaptic structures-focusing mainly on cytoskeletal dynamics and CAMs-and discuss potential mechanoregulation of synapses and its relevance to neurodegenerative diseases.
- Published
- 2018
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29. Spike timing precision of neuronal circuits.
- Author
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Kilinc D and Demir A
- Subjects
- Animals, Feedback, Physiological physiology, Humans, Neural Inhibition physiology, Stochastic Processes, Time Factors, Action Potentials physiology, Models, Neurological, Nerve Net physiology, Synapses physiology, Time Perception physiology
- Abstract
Spike timing is believed to be a key factor in sensory information encoding and computations performed by the neurons and neuronal circuits. However, the considerable noise and variability, arising from the inherently stochastic mechanisms that exist in the neurons and the synapses, degrade spike timing precision. Computational modeling can help decipher the mechanisms utilized by the neuronal circuits in order to regulate timing precision. In this paper, we utilize semi-analytical techniques, which were adapted from previously developed methods for electronic circuits, for the stochastic characterization of neuronal circuits. These techniques, which are orders of magnitude faster than traditional Monte Carlo type simulations, can be used to directly compute the spike timing jitter variance, power spectral densities, correlation functions, and other stochastic characterizations of neuronal circuit operation. We consider three distinct neuronal circuit motifs: Feedback inhibition, synaptic integration, and synaptic coupling. First, we show that both the spike timing precision and the energy efficiency of a spiking neuron are improved with feedback inhibition. We unveil the underlying mechanism through which this is achieved. Then, we demonstrate that a neuron can improve on the timing precision of its synaptic inputs, coming from multiple sources, via synaptic integration: The phase of the output spikes of the integrator neuron has the same variance as that of the sample average of the phases of its inputs. Finally, we reveal that weak synaptic coupling among neurons, in a fully connected network, enables them to behave like a single neuron with a larger membrane area, resulting in an improvement in the timing precision through cooperation.
- Published
- 2018
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- View/download PDF
30. Noise in Neuronal and Electronic Circuits: A General Modeling Framework and Non-Monte Carlo Simulation Techniques.
- Author
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Kilinc D and Demir A
- Subjects
- Algorithms, Humans, Markov Chains, Monte Carlo Method, Stochastic Processes, Computer Simulation, Models, Neurological, Neurons physiology, Synapses
- Abstract
The brain is extremely energy efficient and remarkably robust in what it does despite the considerable variability and noise caused by the stochastic mechanisms in neurons and synapses. Computational modeling is a powerful tool that can help us gain insight into this important aspect of brain mechanism. A deep understanding and computational design tools can help develop robust neuromorphic electronic circuits and hybrid neuroelectronic systems. In this paper, we present a general modeling framework for biological neuronal circuits that systematically captures the nonstationary stochastic behavior of ion channels and synaptic processes. In this framework, fine-grained, discrete-state, continuous-time Markov chain models of both ion channels and synaptic processes are treated in a unified manner. Our modeling framework features a mechanism for the automatic generation of the corresponding coarse-grained, continuous-state, continuous-time stochastic differential equation models for neuronal variability and noise. Furthermore, we repurpose non-Monte Carlo noise analysis techniques, which were previously developed for analog electronic circuits, for the stochastic characterization of neuronal circuits both in time and frequency domain. We verify that the fast non-Monte Carlo analysis methods produce results with the same accuracy as computationally expensive Monte Carlo simulations. We have implemented the proposed techniques in a prototype simulator, where both biological neuronal and analog electronic circuits can be simulated together in a coupled manner.
- Published
- 2017
- Full Text
- View/download PDF
31. Neuronal Cell Bodies Remotely Regulate Axonal Growth Response to Localized Netrin-1 Treatment via Second Messenger and DCC Dynamics.
- Author
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Blasiak A, Kilinc D, and Lee GU
- Abstract
Netrin-1 modulates axonal growth direction and speed. Its best characterized receptor, Deleted in Colorectal Cancer (DCC), is localized to growth cones, but also observed in the cell bodies. We hypothesized that cell bodies sense Netrin-1 and contribute to axon growth rate modulation, mediated by the second messenger system. We cultured mouse cortical neurons in microfluidic devices to isolate distal axon and cell body microenvironments. Compared to isolated axonal treatment, global Netrin-1 treatment decreased the axon elongation rate and affected the dynamics of total and membranous DCC, calcium, and cyclic nucleotides. Signals induced by locally applied Netrin-1 propagated in both anterograde and retrograde directions, demonstrated by the long-range increase in DCC and by the increased frequency of calcium transients in cell bodies, evoked by axonal Netrin-1. Blocking the calcium efflux from endoplasmic reticulum suppressed the membranous DCC response. Our findings support the notion that neurons sense Netrin-1 along their entire lengths in making axonal growth decisions.
- Published
- 2017
- Full Text
- View/download PDF
32. Bio-Nano-Magnetic Materials for Localized Mechanochemical Stimulation of Cell Growth and Death.
- Author
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Kilinc D, Dennis CL, and Lee GU
- Subjects
- Hyperthermia, Induced, Magnetic Fields, Magnetite Nanoparticles, Mechanotransduction, Cellular, Magnetics
- Abstract
Magnetic nanoparticles are promising new tools for therapeutic applications, such as magnetic nanoparticle hyperthermia therapy and targeted drug delivery. Recent in vitro studies have demonstrated that a force application with magnetic tweezers can also affect cell fate, suggesting a therapeutic potential for magnetically modulated mechanical stimulation. The magnetic properties of nanoparticles that induce physical responses and the subtle responses that result from mechanically induced membrane damage and/or intracellular signaling are evaluated. Magnetic particles with various physical, geometric, and magnetic properties and specific functionalization can now be used to apply mechanical force to specific regions of cells, which permit the modulation of cellular behavior through the use of spatially and time controlled magnetic fields. On one hand, mechanochemical stimulation has been used to direct the outgrowth on neuronal growth cones, indicating a therapeutic potential for neural repair. On the other hand, it has been used to kill cancer cells that preferentially express specific receptors. Advances made in the synthesis and characterization of magnetic nanomaterials and a better understanding of cellular mechanotransduction mechanisms may support the translation of mechanochemical stimulation into the clinic as an emerging therapeutic approach., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2016
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33. A microfluidic dual gradient generator for conducting cell-based drug combination assays.
- Author
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Kilinc D, Schwab J, Rampini S, Ikpekha OW, Thampi A, Blasiak A, Li P, Schwamborn R, Kolch W, Matallanas D, and Lee GU
- Subjects
- Cell Line, Tumor, Cell Movement drug effects, Cell Movement physiology, Drug Combinations, Equipment Design, Equipment Failure Analysis, Humans, Neoplasms, Experimental pathology, Neoplasms, Experimental physiopathology, Signal Transduction drug effects, Signal Transduction physiology, Treatment Outcome, Antineoplastic Combined Chemotherapy Protocols administration & dosage, Biological Assay instrumentation, Drug Evaluation, Preclinical instrumentation, Flow Injection Analysis instrumentation, Lab-On-A-Chip Devices, Neoplasms, Experimental drug therapy
- Abstract
We present a microfluidic chip that generates linear concentration gradients of multiple solutes that are orthogonally-aligned to each other. The kinetics of gradient formation was characterized using a fluorescent tracer matching the molecular weight of small inhibitory drugs. Live-cell signalling and motility experiments were conducted to demonstrate the potential uses and advantages of the device. A431 epidermoid carcinoma cells, where EGF induces apoptosis in a concentration-dependent manner, were simultaneously exposed to gradients of MEK inhibitor and EGF receptor (EGFR) inhibitor. By monitoring live caspase activation in the entire chip, we were able to quickly assess the combinatorial interaction between MEK and EGFR pathways, which otherwise would require costly and time consuming titration experiments. We also characterized the motility and morphology of MDA-MB-231 breast cancer cells exposed to orthogonal gradients of EGF and EGFR inhibitor. The microfluidic chip not only permitted the quantitative analysis of a population of cells exposed to drug combinations, but also enabled the morphological characterization of individual cells. In summary, our microfluidic device, capable of establishing concentration gradients of multiple compounds over a group of cells, facilitates and accelerates in vitro cell biology experiments, such as those required for cell-based drug combination assays.
- Published
- 2016
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34. Neuron Subpopulations with Different Elongation Rates and DCC Dynamics Exhibit Distinct Responses to Isolated Netrin-1 Treatment.
- Author
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Blasiak A, Lee GU, and Kilinc D
- Subjects
- Animals, Axons physiology, Calcium metabolism, Cell Enlargement, Cell Membrane physiology, Cells, Cultured, Cerebral Cortex cytology, Cerebral Cortex physiology, Cytosol metabolism, DCC Receptor, Endoplasmic Reticulum metabolism, Immunohistochemistry, Mice, Microfluidic Analytical Techniques, Nerve Growth Factors administration & dosage, Netrin-1, Neurons cytology, Pseudopodia physiology, Ryanodine Receptor Calcium Release Channel metabolism, Tumor Suppressor Proteins administration & dosage, Nerve Growth Factors metabolism, Neurons physiology, Receptors, Cell Surface metabolism, Tumor Suppressor Proteins metabolism
- Abstract
Correct wiring of the nervous system requires guidance cues, diffusible or substrate-bound proteins that steer elongating axons to their target tissues. Netrin-1, the best characterized member of the Netrins family of guidance molecules, is known to induce axon turning and modulate axon elongation rate; however, the factors regulating the axonal response to Netrin-1 are not fully understood. Using microfluidics, we treated fluidically isolated axons of mouse primary cortical neurons with Netrin-1 and characterized axon elongation rates, as well as the membrane localization of deleted in colorectal cancer (DCC), a well-established receptor of Netrin-1. The capacity to stimulate and observe a large number of individual axons allowed us to conduct distribution analyses, through which we identified two distinct neuron subpopulations based on different elongation behavior and different DCC membrane dynamics. Netrin-1 reduced the elongation rates in both subpopulations, where the effect was more pronounced in the slow growing subpopulation. Both the source of Ca(2+) influx and the basal cytosolic Ca(2+) levels regulated the effect of Netrin-1, for example, Ca(2+) efflux from the endoplasmic reticulum due to the activation of Ryanodine channels blocked Netrin-1-induced axon slowdown. Netrin-1 treatment resulted in a rapid membrane insertion of DCC, followed by a gradual internalization. DCC membrane dynamics were different in the central regions of the growth cones compared to filopodia and axon shafts, highlighting the temporal and spatial heterogeneity in the signaling events downstream of Netrin-1. Cumulatively, these results demonstrate the power of microfluidic compartmentalization and distribution analysis in describing the complex axonal Netrin-1 response.
- Published
- 2015
- Full Text
- View/download PDF
35. Microtechnologies for studying the role of mechanics in axon growth and guidance.
- Author
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Kilinc D, Blasiak A, and Lee GU
- Abstract
The guidance of axons to their proper targets is not only a crucial event in neurodevelopment, but also a potential therapeutic target for neural repair. Axon guidance is mediated by various chemo- and haptotactic cues, as well as the mechanical interactions between the cytoskeleton and the extracellular matrix (ECM). Axonal growth cones, dynamic ends of growing axons, convert external stimuli to biochemical signals, which, in turn, are translated into behavior, e.g., turning or retraction, via cytoskeleton-matrix linkages. Despite the inherent mechanical nature of the problem, the role of mechanics in axon guidance is poorly understood. Recent years has witnessed the application of a range of microtechnologies in neurobiology, from microfluidic circuits to single molecule force spectroscopy. In this mini-review, we describe microtechnologies geared towards dissecting the mechanical aspects of axon guidance, divided into three categories: controlling the growth cone microenvironment, stimulating growth cones with externally applied forces, and measuring forces exerted by the growth cones. A particular emphasis is given to those studies that combine multiple techniques, as dictated by the complexity of the problem.
- Published
- 2015
- Full Text
- View/download PDF
36. Mechanochemical stimulation of MCF7 cells with rod-shaped Fe-Au Janus particles induces cell death through paradoxical hyperactivation of ERK.
- Author
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Kilinc D, Lesniak A, Rashdan SA, Gandhi D, Blasiak A, Fannin PC, von Kriegsheim A, Kolch W, and Lee GU
- Subjects
- Cell Death drug effects, Enzyme Activation drug effects, Female, Gold pharmacology, Humans, Hyperthermia, Induced methods, Indoles pharmacology, Iron pharmacology, MCF-7 Cells metabolism, Magnetic Fields, Microfluidic Analytical Techniques, Molecular Targeted Therapy methods, Nanotechnology methods, Neuregulin-1 chemistry, Phosphorylation, Physical Stimulation, Proto-Oncogene Proteins B-raf antagonists & inhibitors, Receptor, ErbB-2 metabolism, Sulfonamides pharmacology, Vemurafenib, Extracellular Signal-Regulated MAP Kinases metabolism, Gold chemistry, Iron chemistry, MCF-7 Cells drug effects, Nanotubes chemistry, Neuregulin-1 pharmacology
- Abstract
Multifunctional nanoparticles that actively target-specific tissues are studied for cancer diagnosis and treatment. Magnetically and optically active particles are of particular interest because they enable multiple imaging modalities and physically modulated therapies, such as magnetic hyperthermia. Fe-Au nanorods are synthesized that have a long iron segment, coated with polyethylene glycol, and a short gold tip functionalized with heregulin (HRG), a known ligand of ErbB family of receptors. HRG-nanorods preferentially target MCF7 cells relative to MDA-MB-231 cells, as demonstrated in a novel microfluidics device. Targeting rates of these classical breast cancer cells correlate with their differential expression of ErbB2/3 receptors. HRG-nanorod binding stimulates the extracellular signal-regulated kinase 1/2 (ERK) phosphorylation in MCF7 cells. The increase in ERK phosphorylation is linked to "active zones," dynamic regions in the cell periphery, which exhibit higher rates of particle binding than the rest of the cell. Periodically stretching cells using magnetic tweezers further activates ERK, which leads to cell death in cells co-treated with B-Raf inhibitors, through ERK hyperactivation. Although to a lesser extent, cell death is also achieved through magnetic hyperthermia. These results demonstrate nanoscale targeting and localized mechanochemical treatment of specific cancer cell lines based on their receptor expression using multifunctional nanoparticles., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2015
- Full Text
- View/download PDF
37. Low piconewton towing of CNS axons against diffusing and surface-bound repellents requires the inhibition of motor protein-associated pathways.
- Author
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Kilinc D, Blasiak A, O'Mahony JJ, and Lee GU
- Subjects
- Amides pharmacology, Animals, Axons drug effects, Cells, Cultured, Chondroitin Sulfates chemistry, Chondroitin Sulfates metabolism, Diffusion, Mice, Microfluidic Analytical Techniques, Models, Biological, Molecular Motor Proteins antagonists & inhibitors, Neurons cytology, Pyridines pharmacology, Semaphorin-3A metabolism, rhoA GTP-Binding Protein antagonists & inhibitors, rhoA GTP-Binding Protein metabolism, Axons physiology, Central Nervous System metabolism, Molecular Motor Proteins metabolism
- Abstract
Growth cones, dynamic structures at axon tips, integrate chemical and physical stimuli and translate them into coordinated axon behaviour, e.g., elongation or turning. External force application to growth cones directs and enhances axon elongation in vitro; however, direct mechanical stimulation is rarely combined with chemotactic stimulation. We describe a microfluidic device that exposes isolated cortical axons to gradients of diffusing and substrate-bound molecules, and permits the simultaneous application of piconewton (pN) forces to multiple individual growth cones via magnetic tweezers. Axons treated with Y-27632, a RhoA kinase inhibitor, were successfully towed against Semaphorin 3A gradients, which repel untreated axons, with less than 12 pN acting on a small number of neural cell adhesion molecules. Treatment with Y-27632 or monastrol, a kinesin-5 inhibitor, promoted axon towing on substrates coated with chondroitin sulfate proteoglycans, potent axon repellents. Thus, modulating key molecular pathways that regulate contractile stress generation in axons counteracts the effects of repellent molecules and promotes tension-induced growth. The demonstration of parallel towing of axons towards inhibitory environments with minute forces suggests that mechanochemical stimulation may be a promising therapeutic approach for the repair of the damaged central nervous system, where regenerating axons face repellent factors over-expressed in the glial scar.
- Published
- 2014
- Full Text
- View/download PDF
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