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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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Hsu YH, Chen YC, Chen YW, Chiu TH, Kuo YT, Chen CH. Far-infrared radiation prevents decline in β-cell mass and function in diabetic mice via the mitochondria-mediated Sirtuin1 pathway. Metabolism 2020; 104:154143. [PMID: 31927009 DOI: 10.1016/j.metabol.2020.154143] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 12/30/2019] [Accepted: 01/08/2020] [Indexed: 12/11/2022]
Abstract
Insulin deficiency in type 2 diabetes mellitus (DM) involves a decline in both pancreatic β-cell mass and function. Enhancing β-cell preservation represents an important therapeutic strategy to treat type 2 DM. Far-infrared (FIR) radiation has been found to induce promyelocytic leukemia zinc finger protein (PLZF) activation to protect the vascular endothelium in diabetic mice. The influence of FIR on β-cell preservation is unknown. Our previous study reveals that the biologically effective wavelength of FIR is 8-10 μm. In the present study, we investigated the biological effects of FIR (8-10 μm) on both survival and insulin secretion function of β-cells. FIR reduced pancreatic islets loss and increased insulin secretion in nicotinamide-streptozotocin-induced DM mice, but only promoted insulin secretion in DM PLZF-/- mice. FIR-upregulated PLZF to induce an anti-apoptotic effect in a β cell line RIN-m5f. FIR also upregulated mitochondrial function and the ratio of NAD+/NADH, and then induced Sirtuin1 (Sirt1) expression. The mitochondria Complex I inhibitor rotenone blocked FIR-induced PLZF and Sirt1. The Sirt1 inhibitor EX527 and Sirt1 siRNA inhibited FIR-induced PLZF and insulin respectively. Sirt1 upregulation also increased CaV1.2 expression and calcium influx that promotes insulin secretion in β-cells. In summary, FIR-enhanced mitochondrial function prevents β-cell apoptosis and enhances insulin secretion in DM mice through the Sirt1 pathway.
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Affiliation(s)
- Yung-Ho Hsu
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taiwan; Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taiwan
| | - Yen-Cheng Chen
- Division of Nephrology, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taiwan
| | - Yu-Wei Chen
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taiwan
| | - Tzu-Hsuan Chiu
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taiwan
| | - Yung-Ting Kuo
- Department of Pediatrics, Shuang Ho Hospital, Taipei Medical University, Taiwan; Department of Pediatrics, School of Medicine, College of Medicine, Taipei Medical University, Taiwan
| | - Cheng-Hsien Chen
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taiwan; Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taiwan; Division of Nephrology, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taiwan.
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