The Localization of Pancreatic Islets Utilizing a Green Fluorescent Protein Proinsulin Mouse Model – UROP Summer Symposium 2021

The Localization of Pancreatic Islets Utilizing a Green Fluorescent Protein Proinsulin Mouse Model

Gladys Kamdem

Gladys Kamdem

Pronouns: She/Her/Hers

UROP Fellowship: CCSFP, Lansing Community College
Research Mentor(s): Peter Arvan MD, PhD & Dennis Larkin
Research Mentor Institution/Department: Michigan Medicine, Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes

Presentation Date: Wednesday, August 4th
Session: Session 3 (5pm-6:20pm EDT)
Breakout Room: Room 3
Presenter: 7

Event Link

Abstract

Diabetes affects about 463 million people worldwide. It can cause various complications that affect several organs in the body. Diabetes is a disease that can be caused by insufficient insulin production. Insulin is synthesized in pancreatic beta cells located in clusters called islets. The laboratory of Dr. Peter Arvan at the University of Michigan is interested in the role of protein misfolding, and quality control systems including unfolded protein response (UPR), and endoplasmic reticulum associated-protein degradation (ERAD) in the development of diabetes. The physiological and genetic similarities between mice and humans allow the use of transgenic mouse models for laboratory studies. Green fluorescent protein (GFP) is used as a visible tag for localization and relative quantification of insulin content thereby allowing us to locate and measure the intensity of the signal in pancreatic islets. A transgenic GFP/hWTProinsulin mouse line was created by insertion of GFP into the C-peptide region of human proinsulin forming a transgene that was introduced into fertilized mouse oocytes via microinjection. Currently, the GFP/hWTProinsulin mouse model is being utilized for two main applications. In study #1, the GFP transgenic mouse was crossed with an insulin KO mouse line to generate mice with serial deletion of the two endogenous mouse insulin alleles. The insulin-containing islets can be tracked by microscopy using GFP fluorescence. To view the signal intensity of the GFP-proinsulin expression, the pancreas was imaged on a fluorescence microscope. Compensatory upregulation of the transgenic human proinsulin due to serial deletion of endogenous mouse insulin was insufficient to maintain euglycemia in this mouse line. The transgenic mice only survived for about 48-72 hours. In study #2 the GFPproinsulin and non-obese diabetic (NOD) model was crossed to produce the GFPproinsulin-NOD mouse model. This mouse line studies the progression of type 1 diabetes at each stage of its development by analysis through blood glucose measurements and islet GFP imaging throughout the development of diabetes.

 

Authors: Gladys Kamdem, Dennis Larkin, Taylor W Cook, Peter Arvan
Research Method: Laboratory Research

lsa logoum logo