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Fontaine AK, Futia GL, Rajendran PS, Littich SF, Mizoguchi N, Shivkumar K, Ardell JL, Restrepo D, Caldwell JH, Gibson EA, Weir RFF. Optical vagus nerve modulation of heart and respiration via heart-injected retrograde AAV. Sci Rep 2021; 11:3664. [PMID: 33574459 PMCID: PMC7878800 DOI: 10.1038/s41598-021-83280-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 01/18/2021] [Indexed: 12/16/2022] Open
Abstract
Vagus nerve stimulation has shown many benefits for disease therapies but current approaches involve imprecise electrical stimulation that gives rise to off-target effects, while the functionally relevant pathways remain poorly understood. One method to overcome these limitations is the use of optogenetic techniques, which facilitate targeted neural communication with light-sensitive actuators (opsins) and can be targeted to organs of interest based on the location of viral delivery. Here, we tested whether retrograde adeno-associated virus (rAAV2-retro) injected in the heart can be used to selectively express opsins in vagus nerve fibers controlling cardiac function. Furthermore, we investigated whether perturbations in cardiac function could be achieved with photostimulation at the cervical vagus nerve. Viral injection in the heart resulted in robust, primarily afferent, opsin reporter expression in the vagus nerve, nodose ganglion, and brainstem. Photostimulation using both one-photon stimulation and two-photon holography with a GRIN-lens incorporated nerve cuff, was tested on the pilot-cohort of injected mice. Changes in heart rate, surface electrocardiogram, and respiratory responses were observed in response to both one- and two-photon photostimulation. The results demonstrate feasibility of retrograde labeling for organ targeted optical neuromodulation.
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Affiliation(s)
- Arjun K Fontaine
- Departments of Bioengineering, University of Colorado - Anschutz Medical Campus, Aurora, CO, USA.
- Biomechatronics Development Laboratory, University of Colorado - Anschutz Medical Campus, Aurora, CO, USA.
| | - Gregory L Futia
- Departments of Bioengineering, University of Colorado - Anschutz Medical Campus, Aurora, CO, USA
| | - Pradeep S Rajendran
- UCLA Cardiac Arrhythmia Center, University of California Los Angeles, Los Angeles, CA, USA
- UCLA Neurocardiology Research Program of Excellence, University of California Los Angeles, Los Angeles, CA, USA
| | - Samuel F Littich
- Departments of Bioengineering, University of Colorado - Anschutz Medical Campus, Aurora, CO, USA
- Biomechatronics Development Laboratory, University of Colorado - Anschutz Medical Campus, Aurora, CO, USA
| | - Naoko Mizoguchi
- Departments of Cell and Developmental Biology, University of Colorado - Anschutz Medical Campus, Aurora, CO, USA
- Division of Pharmacology, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, Saitama, Japan
| | - Kalyanam Shivkumar
- UCLA Cardiac Arrhythmia Center, University of California Los Angeles, Los Angeles, CA, USA
- UCLA Neurocardiology Research Program of Excellence, University of California Los Angeles, Los Angeles, CA, USA
| | - Jeffrey L Ardell
- UCLA Cardiac Arrhythmia Center, University of California Los Angeles, Los Angeles, CA, USA
- UCLA Neurocardiology Research Program of Excellence, University of California Los Angeles, Los Angeles, CA, USA
| | - Diego Restrepo
- Departments of Cell and Developmental Biology, University of Colorado - Anschutz Medical Campus, Aurora, CO, USA
| | - John H Caldwell
- Departments of Cell and Developmental Biology, University of Colorado - Anschutz Medical Campus, Aurora, CO, USA
| | - Emily A Gibson
- Departments of Bioengineering, University of Colorado - Anschutz Medical Campus, Aurora, CO, USA
| | - Richard F Ff Weir
- Departments of Bioengineering, University of Colorado - Anschutz Medical Campus, Aurora, CO, USA
- Biomechatronics Development Laboratory, University of Colorado - Anschutz Medical Campus, Aurora, CO, USA
- Rocky Mountain Veterans Affairs Medical Center (VAMC), Aurora, CO, USA
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Fontaine AK, Ramirez DG, Littich SF, Piscopio RA, Kravets V, Schleicher WE, Mizoguchi N, Caldwell JH, Weir RFF, Benninger RKP. Optogenetic stimulation of cholinergic fibers for the modulation of insulin and glycemia. Sci Rep 2021; 11:3670. [PMID: 33574598 PMCID: PMC7878862 DOI: 10.1038/s41598-021-83361-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 02/01/2021] [Indexed: 01/12/2023] Open
Abstract
Previous studies have demonstrated stimulation of endocrine pancreas function by vagal nerve electrical stimulation. While this increases insulin secretion, expected concomitant reductions in circulating glucose do not occur. A complicating factor is the non-specific nature of electrical nerve stimulation. Optogenetic tools, however, provide the potential for cell-type specific neural stimulation using genetic targeting and/or spatially shaped excitation light. Here, we demonstrate light-activated stimulation of the endocrine pancreas by targeting parasympathetic (cholinergic) axons. In a mouse model expressing ChannelRhodopsin2 (ChR2) in cholinergic cells, serum insulin and glucose were measured in response to (1) ultrasound image-guided optical stimulation of axon terminals in the pancreas or (2) optical stimulation of axons of the cervical vagus nerve. Measurements were made in basal-glucose and glucose-stimulated conditions. Significant increases in plasma insulin occurred relative to controls under both pancreas and cervical vagal stimulation, while a rapid reduction in glycemic levels were observed under pancreatic stimulation. Additionally, ultrasound-based measurements of blood flow in the pancreas were increased under pancreatic stimulation. Together, these results demonstrate the utility of in-vivo optogenetics for studying the neural regulation of endocrine pancreas function and suggest its therapeutic potential for the control of insulin secretion and glucose homeostasis.
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Affiliation(s)
- Arjun K Fontaine
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Boulder, USA.
- Biomechatronics Development Laboratory, University of Colorado, Anschutz Medical Campus, Boulder, USA.
| | - David G Ramirez
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Boulder, USA
- Barbara Davis Center for Childhood Diabetes - Anschutz Medical Campus, Boulder, USA
| | - Samuel F Littich
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Boulder, USA
- Biomechatronics Development Laboratory, University of Colorado, Anschutz Medical Campus, Boulder, USA
| | - Robert A Piscopio
- Barbara Davis Center for Childhood Diabetes - Anschutz Medical Campus, Boulder, USA
| | - Vira Kravets
- Barbara Davis Center for Childhood Diabetes - Anschutz Medical Campus, Boulder, USA
| | | | - Naoko Mizoguchi
- Division of Pharmacology, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, Saitama, Japan
| | - John H Caldwell
- Department of Cell and Developmental Biology, University of Colorado, Anschutz Medical Campus, Boulder, USA
| | - Richard F Ff Weir
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Boulder, USA
- Biomechatronics Development Laboratory, University of Colorado, Anschutz Medical Campus, Boulder, USA
| | - Richard K P Benninger
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Boulder, USA.
- Barbara Davis Center for Childhood Diabetes - Anschutz Medical Campus, Boulder, USA.
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