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Firlar E, Ouy M, Covnot L, Xing Y, Lee D, Chan A, He Y, Song B, Afelik S, Wang Y, Shahbazian-Yassar R, Oberholzer J, Shokuhfar T. In situ graphene liquid cell-transmission electron microscopy study of insulin secretion in pancreatic islet cells. Int J Nanomedicine 2019; 14:371-382. [PMID: 30662261 PMCID: PMC6327893 DOI: 10.2147/ijn.s169506] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Islet cell transplantation is one of the key treatments for type 1 diabetes. Understanding the mechanisms of insulin fusion and exocytosis are of utmost importance for the improvement of the current islet cell transplantation and treatment of diabetes. These phenomena have not been fully evaluated due either to the lack of proper dynamic imaging, or the lack of proper cell preservation during imaging at nanoscales. METHODS By maintaining the native environment of pancreatic β-cells between two graphene monolayer sheets, we were able to monitor the subcellular events using in situ graphene liquid cell (GLC)-transmission electron microscopy (TEM) with both high temporal and high spatial resolution. RESULTS For the first time, the nucleation and growth of insulin particles until the later stages of fusion were imaged at nanometer scales. The release of insulin from plasma membrane involves the degradation of plasma membrane and drastic reductions in the shorter axis of the insulin particles. Sequential exocytosis results indicated the nucleation, growth and attachment of the new insulin particles to the already anchored ones, which is thermodynamically favorable due to the reduction in total surface, further reducing the Gibbs free energy. The retraction of the already anchored insulin toward the cell is also monitored for the first time live at nanoscale resolution. CONCLUSION Investigation of insulin granule dynamics in β-cells can be investigated via GLC-TEM. Our findings with this technology open new realms for the development of novel drugs on pathological pancreatic β-cells, because this approach facilitates observing the effects of the stimuli on the live cells and insulin granules.
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Affiliation(s)
- Emre Firlar
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA,
- University of Illinois at Chicago, Department of Mechanical and Industrial Engineering, Chicago, IL, USA,
| | - Meagan Ouy
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA,
| | - Leigha Covnot
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA,
| | - Yuan Xing
- University of Virginia, Department of Surgery, Charlottesville, VA, USA
| | - Daniel Lee
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA,
- University of Illinois at Chicago, Department of Surgery, Chicago, IL, USA
| | - Alessandro Chan
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA,
- University of Illinois at Chicago, Department of Surgery, Chicago, IL, USA
| | - Yi He
- University of Virginia, Department of Surgery, Charlottesville, VA, USA
| | - Boao Song
- University of Illinois at Chicago, Department of Mechanical and Industrial Engineering, Chicago, IL, USA,
| | - Solomon Afelik
- University of Illinois at Chicago, Department of Surgery, Chicago, IL, USA
| | - Yong Wang
- University of Virginia, Department of Surgery, Charlottesville, VA, USA
| | - Reza Shahbazian-Yassar
- University of Illinois at Chicago, Department of Mechanical and Industrial Engineering, Chicago, IL, USA,
| | - Jose Oberholzer
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA,
- University of Virginia, Department of Surgery, Charlottesville, VA, USA
| | - Tolou Shokuhfar
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA,
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Wang X, Wang K, Zhang W, Qiang M, Luo Y. A bilaminated decellularized scaffold for islet transplantation: Structure, properties and functions in diabetic mice. Biomaterials 2017; 138:80-90. [DOI: 10.1016/j.biomaterials.2017.05.033] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 05/18/2017] [Accepted: 05/19/2017] [Indexed: 12/12/2022]
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