Effect of Frataxin Knockout on Mouse Cardiomyocytes Using DsRed.T3 as a Quantifying Marker

  • Eric Galante
  • P Melanie Pride
  • Frances Chen, MD
  • R Mark Payne, MD

Abstract

Background: Discosoma Red (DsRed) is a strong fluorescent marker that has many practical uses for scientific studies. We engineered a transgenic mouse expressing DsRed.T3 only in cardiomyocyte nuclei, and then crossed this with a conditional knockout mouse with loss of Frataxin (FXN) in heart. It is known that dysfunction of the Frataxin (FXN) gene can cause Friedrich’s Ataxia (FRDA), a disease associated with ataxia, weakness and dilated cardiomyopathy in humans. The current study aimed to: 1) Determine if DsRed overexpression in cardiomyocyte nuclei would negatively affect cardiac tissue, and 2) Use the DsRed.T3 mouse to determine whether FXN knockout (KO) would cause a loss of cardiomyocytes.

Methods: The study was done by examining three different strains of mice: wild-type, DsRed.T.3 overexpressing Tg mice, and FXN KO mice with loss of FXN in cardiomyocytes. Mice were analyzed using genotyping, frozen immunofluorescent stains, α-actinin and Hoechst, TPLSM, confocal microscopy, western blotting, H&E, echocardiography, and heart:body weight ratios.
Results: DsRed.T3 is localized to the nucleus of cardiomyocytes. At 6.5 months of age, there were significant effects on cardiac function. It was also shown that there was a loss of cardiomyocyte nuclei in the FXN KO group.

Conclusion: This study shows how researchers can study the heart, and more specifically, Friedreich’s Ataxia, while also shedding light on how FXN loss may ultimately affect the heart in FRDA patients.

Published
2019-07-26
Section
Indiana Medical Student Program for Research and Scholarship Oral Presentations