Impact of the Microtubule Cytoskeleton on Insulin Transport in Beta Cells: A 3D Computational Study

Overview

Journal bioRxiv

Date 2025 Feb 24

PMID 39990414

Authors

Thoa Thieu

William R Holmes

Affiliations

Soon will be listed here.

Abstract

Glucose-stimulated insulin secretion (GSIS) in pancreatic cells is vital to metabolic homeostasis. Recent evidence has highlighted the critical role of the cells' microtubule (MT) cytoskeleton in regulating transport and availability of insulin containing vesicles. How these vesicles move within the cell and how that mobility is influenced by the MT network is however not well understood. The MT network in these cells is dense and randomly oriented. Further insulin vesicles are relatively large compared to the spaces in this dense meshwork. Here we develop a 3D computational model that simulates vesicle motions in the dense MT network of the cell. The structure of this MT network, along with the dynamics of vesicle motions, are calibrated to microscopy data from cells to ensure physiological relevance. Our results reveal a number of key observations. 1) The MT network in cells likely impairs motion of larger vesicles (200 - 300 in diameter). 2) This is in part a consequence of their "caging" by the MT network. 3) This results in a substantial reduction in the likelihood of vesicles transiting from the cells interior to the plasma membrane, a pre-cursor to GSIS. 4) Dynamic remodeling of the MT network reduces the strength of these effects. 5) That same remodeling however introduces anomalous (sub-diffusion) motion characteristics. Taken together, these results indicate that the dense MT network of the cell substantially inhibits mobility and availability (for GSIS) of insulin. It further sheds light on how the complex filament network in cells leads to statistically anomalous motions. Finally, this modeling further provides a test-bed for determining how potential manipulations of the structure and dynamics of this network would tune GSIS.

References

Stokes A, Preston S . Deaths Attributable to Diabetes in the United States: Comparison of Data Sources and Estimation Approaches. PLoS One. 2017; 12(1):e0170219. PMC: 5266275. DOI: 10.1371/journal.pone.0170219. View

Rorsman P, Ashcroft F . Pancreatic β-Cell Electrical Activity and Insulin Secretion: Of Mice and Men. Physiol Rev. 2017; 98(1):117-214. PMC: 5866358. DOI: 10.1152/physrev.00008.2017. View

Donelan M, Morfini G, Julyan R, Sommers S, Hays L, Kajio H . Ca2+-dependent dephosphorylation of kinesin heavy chain on beta-granules in pancreatic beta-cells. Implications for regulated beta-granule transport and insulin exocytosis. J Biol Chem. 2002; 277(27):24232-42. DOI: 10.1074/jbc.M203345200. View

Arif S, Moulin V . Extracellular vesicles on the move: Traversing the complex matrix of tissues. Eur J Cell Biol. 2023; 102(4):151372. DOI: 10.1016/j.ejcb.2023.151372. View

Trimble W, Grinstein S . Barriers to the free diffusion of proteins and lipids in the plasma membrane. J Cell Biol. 2015; 208(3):259-71. PMC: 4315255. DOI: 10.1083/jcb.201410071. View

Dix J, Verkman A . Crowding effects on diffusion in solutions and cells. Annu Rev Biophys. 2008; 37:247-63. DOI: 10.1146/annurev.biophys.37.032807.125824. View

Hepburn I, Lallouette J, Chen W, Gallimore A, Nagasawa-Soeda S, De Schutter E . Vesicle and reaction-diffusion hybrid modeling with STEPS. Commun Biol. 2024; 7(1):573. PMC: 11096338. DOI: 10.1038/s42003-024-06276-5. View

Zhu X, Hu R, Brissova M, Stein R, Powers A, Gu G . Microtubules Negatively Regulate Insulin Secretion in Pancreatic β Cells. Dev Cell. 2015; 34(6):656-68. PMC: 4594944. DOI: 10.1016/j.devcel.2015.08.020. View

Pratley R, Weyer C . The role of impaired early insulin secretion in the pathogenesis of Type II diabetes mellitus. Diabetologia. 2001; 44(8):929-45. DOI: 10.1007/s001250100580. View

10.

Tabei S, Burov S, Kim H, Kuznetsov A, Huynh T, Jureller J . Intracellular transport of insulin granules is a subordinated random walk. Proc Natl Acad Sci U S A. 2013; 110(13):4911-6. PMC: 3612641. DOI: 10.1073/pnas.1221962110. View

11.

Petersen M, Shulman G . Mechanisms of Insulin Action and Insulin Resistance. Physiol Rev. 2018; 98(4):2133-2223. PMC: 6170977. DOI: 10.1152/physrev.00063.2017. View

12.

Heaslip A, Nelson S, Lombardo A, Previs S, Armstrong J, Warshaw D . Cytoskeletal dependence of insulin granule movement dynamics in INS-1 beta-cells in response to glucose. PLoS One. 2014; 9(10):e109082. PMC: 4195697. DOI: 10.1371/journal.pone.0109082. View

13.

Arous C, Halban P . The skeleton in the closet: actin cytoskeletal remodeling in β-cell function. Am J Physiol Endocrinol Metab. 2015; 309(7):E611-20. DOI: 10.1152/ajpendo.00268.2015. View

14.

Sittewelle M, Royle S . Passive diffusion accounts for the majority of intracellular nanovesicle transport. Life Sci Alliance. 2023; 7(1). PMC: 10587482. DOI: 10.26508/lsa.202302406. View

15.

Somers G, Van Obberghen E, Devis G, Ravazzola M, Malaisse-Lagae F, Malaisse W . Dynamics of insulin release and microtubular-microfilamentous system. III. Effect of colchicine upon glucose-induced insulin secretion. Eur J Clin Invest. 1974; 4(5):299-305. DOI: 10.1111/j.1365-2362.1974.tb00407.x. View

16.

Ho K, Yang X, Osipovich A, Cabrera O, Hayashi M, Magnuson M . Glucose Regulates Microtubule Disassembly and the Dose of Insulin Secretion via Tau Phosphorylation. Diabetes. 2020; 69(9):1936-1947. PMC: 7458041. DOI: 10.2337/db19-1186. View

17.

Roux A, Gilbert S, Loranger A, Marceau N . Impact of keratin intermediate filaments on insulin-mediated glucose metabolism regulation in the liver and disease association. FASEB J. 2015; 30(2):491-502. DOI: 10.1096/fj.15-277905. View

18.

You J, Wang Z, Xu S, Zhang W, Fang Q, Liu H . Advanced Glycation End Products Impair Glucose-Stimulated Insulin Secretion of a Pancreatic β-Cell Line INS-1-3 by Disturbance of Microtubule Cytoskeleton via p38/MAPK Activation. J Diabetes Res. 2016; 2016:9073037. PMC: 5011238. DOI: 10.1155/2016/9073037. View

19.

DeFronzo R, Ferrannini E, Groop L, Henry R, Herman W, Holst J . Type 2 diabetes mellitus. Nat Rev Dis Primers. 2016; 1:15019. DOI: 10.1038/nrdp.2015.19. View

20.

Rorsman P, Renstrom E . Insulin granule dynamics in pancreatic beta cells. Diabetologia. 2003; 46(8):1029-45. DOI: 10.1007/s00125-003-1153-1. View