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Mehrabi H, Bansal P, Jutoy J, Chan YH, Roitman MF, Gao R, Jung EE. Optogenetic activation of hypothalamic AgRP neurons in transgenic zebrafish larvae increased food intake. Sci Rep 2025; 15:17976. [PMID: 40410389 PMCID: PMC12102260 DOI: 10.1038/s41598-025-03040-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2024] [Accepted: 05/19/2025] [Indexed: 05/25/2025] Open
Abstract
Agouti Related Peptide (AgRP) neurons are located in the hypothalamus, and upon stimulation, these neurons regulate hunger and hunger-mediated behaviors, especially food-seeking and compulsive eating. AgRP neurons are naturally activated by ghrelin binding onto the ghrelin receptors on the neuron surface during starvation or fasting state to evoke the aforementioned behaviors. In this study, we used channelrhodopsin (ChR2), an optogenetic actuator, to control AgRP neuronal activity. For the first time, we observed food-intake behavior in zebrafish larvae by optogenetically triggering AgRP1 neurons. We created a transgenic line, Tg(AgRP1:ChR2-Kaede), where ChR2-Kaede is expressed in AgRP1 neurons. Transgenic zebrafish Tg(AgRP1:ChR2-Kaede) larvae at 6 days post fertilization and wild-type (ABWT) larvae were used to compare the suction behavior. We found that AgRP1 neuron activation in transgenic larvae led to a significantly higher food-consumption behavior than wildtype larvae when analyzed using Particle Image Velocimetry (PIV) to calculate the food particle velocity initiated by larval suction behavior. These findings in this novel transgenic zebrafish model would be useful in studying various hunger-related behaviors, their underlying neural circuits, and substrates subjected to different chemical stimuli, including drugs of abuse.
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Affiliation(s)
- Hossein Mehrabi
- Department of Mechanical Engineering, University of Illinois Chicago, 842 W Taylor St, Chicago, IL, 60607, USA
| | - Pushkar Bansal
- Department of Pharmacology and Toxicology, The University of Utah, 30S 2000E, Salt Lake City, UT, 84112, USA
| | - John Jutoy
- Department of Mechanical Engineering, University of Illinois Chicago, 842 W Taylor St, Chicago, IL, 60607, USA
| | - Yat Ho Chan
- Department of Chemistry, University of Illinois Chicago, 845 W Taylor St, Chicago, IL, 60607, USA
| | - Mitchell F Roitman
- Department of Psychology, University of Illinois Chicago, 1007 W Harrison St, Chicago, IL, 60607, USA
| | - Ruixuan Gao
- Department of Chemistry, University of Illinois Chicago, 845 W Taylor St, Chicago, IL, 60607, USA
- Department of Biological Sciences, University of Illinois Chicago, 845 W Taylor St, Chicago, IL, 60607, USA
| | - Erica E Jung
- Department of Mechanical Engineering, University of Illinois Chicago, 842 W Taylor St, Chicago, IL, 60607, USA.
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois Chicago, 851 S Morgan St, Chicago, IL, 60607, USA.
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Shaner S, Lu H, Lenz M, Garg S, Vlachos A, Asplund M. Brain stimulation-on-a-chip: a neuromodulation platform for brain slices. LAB ON A CHIP 2023; 23:4967-4985. [PMID: 37909911 PMCID: PMC10661668 DOI: 10.1039/d3lc00492a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 10/15/2023] [Indexed: 11/03/2023]
Abstract
Electrical stimulation of ex vivo brain tissue slices has been a method used to understand mechanisms imparted by transcranial direct current stimulation (tDCS), but there are significant direct current electric field (dcEF) dosage and electrochemical by-product concerns in conventional experimental setups that may impact translational findings. Therefore, we developed an on-chip platform with fluidic, electrochemical, and magnetically-induced spatial control. Fluidically, the chamber geometrically confines precise dcEF delivery to the enclosed brain slice and allows for tissue recovery in order to monitor post-stimulation effects. Electrochemically, conducting hydrogel electrodes mitigate stimulation-induced faradaic reactions typical of commonly-used metal electrodes. Magnetically, we applied ferromagnetic substrates beneath the tissue and used an external permanent magnet to enable in situ rotational control in relation to the dcEF. By combining the microfluidic chamber with live-cell calcium imaging and electrophysiological recordings, we showcased the potential to study the acute and lasting effects of dcEFs with the potential of providing multi-session stimulation. This on-chip bioelectronic platform presents a modernized yet simple solution to electrically stimulate explanted tissue by offering more environmental control to users, which unlocks new opportunities to conduct thorough brain stimulation mechanistic investigations.
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Affiliation(s)
- Sebastian Shaner
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg im Breisgau, Germany
- BrainLinks-BrainTools Center, University of Freiburg, Georges-Köhler-Allee 201, 79110 Freiburg im Breisgau, Germany
| | - Han Lu
- BrainLinks-BrainTools Center, University of Freiburg, Georges-Köhler-Allee 201, 79110 Freiburg im Breisgau, Germany
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Albertstraße 17, 79104 Freiburg im Breisgau, Germany.
| | - Maximilian Lenz
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Albertstraße 17, 79104 Freiburg im Breisgau, Germany.
- Hannover Medical School, Institute of Neuroanatomy and Cell Biology, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
| | - Shreyash Garg
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Albertstraße 17, 79104 Freiburg im Breisgau, Germany.
- MSc Neuroscience Program, Faculty of Biology, University of Freiburg, Schänzlestraße 1, 79104 Freiburg im Breisgau, Germany
| | - Andreas Vlachos
- BrainLinks-BrainTools Center, University of Freiburg, Georges-Köhler-Allee 201, 79110 Freiburg im Breisgau, Germany
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Albertstraße 17, 79104 Freiburg im Breisgau, Germany.
- Center for Basics in Neuromodulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, 79104 Freiburg im Breisgau, Germany
| | - Maria Asplund
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg im Breisgau, Germany
- BrainLinks-BrainTools Center, University of Freiburg, Georges-Köhler-Allee 201, 79110 Freiburg im Breisgau, Germany
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Chalmersplatsen 4, 41258 Gothenburg, Sweden.
- Division of Nursing and Medical Technology, Luleå University of Technology, 79187 Luleå, Sweden
- Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Albertstraße 19, 79104 Freiburg im Breisgau, Germany
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Noor SM, Wong CED, Wong PF, Norazit A. Generation of glial cell-derived neurotrophic factor (gdnf) morphants in zebrafish larvae by cerebroventricular microinjection of vivo morpholino. Methods Cell Biol 2022; 181:17-32. [PMID: 38302238 DOI: 10.1016/bs.mcb.2022.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Dopaminergic neurons in the brain are an important source of dopamine, which is a crucial neurotransmitter for wellbeing, memory, reward, and motor control. Deficiency of dopamine due to advanced age and accumulative dopaminergic neuron defects can lead to movement disorders such as Parkinson's disease. Glial cell-derived neurotrophic factor (GDNF) is one of many factors involved in dopaminergic neuron development and/or survival. However, other endogenous GDNF functions in the brain await further investigation. Zebrafish is a well-established genetic model for neurodevelopment and neurodegeneration studies. Importantly, zebrafish shares approximately 70% functional orthologs with human genes including GDNF. To gain a better understanding on the precise functional role of gdnf in dopaminergic neurons, our laboratory devised a targeted knockdown of gdnf in the zebrafish larval brain using vivo morpholino. Here, detailed protocols on the generation of gdnf morphants using vivo morpholino are outlined. This method can be applied for targeting of genes in the brain to determine specific spatiotemporal gene function in situ.
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Affiliation(s)
- Suzita Mohd Noor
- Department of Biomedical Science, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Chee Ern David Wong
- Department of Biomedical Science, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
| | - Pooi-Fong Wong
- Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Anwar Norazit
- Department of Biomedical Science, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
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Kim K. Single-Shot Light-Field Microscopy: An Emerging Tool for 3D Biomedical Imaging. BIOCHIP JOURNAL 2022. [DOI: 10.1007/s13206-022-00077-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Abstract3D microscopy is a useful tool to visualize the detailed structures and mechanisms of biomedical specimens. In particular, biophysical phenomena such as neural activity require fast 3D volumetric imaging because fluorescence signals degrade quickly. A light-field microscope (LFM) has recently attracted attention as a high-speed volumetric imaging technique by recording 3D information in a single-snapshot. This review highlighted recent progress in LFM techniques for 3D biomedical applications. In detail, various image reconstruction algorithms according to LFM configurations are explained, and several biomedical applications such as neuron activity localization, live-cell imaging, locomotion analysis, and single-molecule visualization are introduced. We also discuss deep learning-based LFMs to enhance image resolution and reduce reconstruction artifacts.
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SUZUKI M, IWAKI Y, TERAO K, KUNIKATA R, SUDA A, Y. INOUE K, INO K, MATSUE T, YASUKAWA T. Simultaneous Monitoring of Oxygen Consumption and Movement of Zebrafish Embryos Based on an LSI-based Electrochemical Multiple-biosensor. BUNSEKI KAGAKU 2021. [DOI: 10.2116/bunsekikagaku.70.535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
| | - Yuka IWAKI
- Graduate School of Science, University of Hyogo
| | | | | | | | - Kumi Y. INOUE
- Faculty of Engineering, Graduate Faculty of Interdisciplinary Research, University of Yamanashi
| | - Kosuke INO
- Graduate School of Environmental Studies, Tohoku University
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