2011 – Electrical activity in a stem cell model of Friedreich Ataxia
This study, undertaken together with Dr Mirella Dottori, examines the function of neurons in Friedreich’s Ataxia (FA), an inherited degenerative disorder affecting the nervous system and heart. This condition results from a disruption in production of a cellular protein known as Frataxin. To help develop effective treatments for FA and better understand the disease mechanisms, we generated ‘embryonic-like stem cells’ from FA patient’s tissue. These cells, known as induced-pluripotent stem (iPS) cells, have similar properties to embryonic stem cells, and can be used to derive any mature cell type.
In this project funded by the Brain Foundation, we are investigating the electrical activity of FA patient-derived iPS neurons as well as ‘corrected’ FA iPS neurons genetically modified with increased Frataxin protein levels. To identify these genetically modified FA iPS cell lines before recording their electrical activity, we induced them to express green fluorescent protein (GFP). With this grant we were able to purchase equipment for visualizing GFP-expressing neurons in culture (Figure 1). In addition to having the corrected FA iPS cell line, we also compared the electrical activity of the FA iPS-derived neurons to neurons derived from human stem cells and control iPS cells, which carry ‘normal’ levels of Frataxin. Data to date suggests that there is little functional difference between these groups, and is consistent with our other tests showing no significant difference in mitochondrial function and cell death between these neurons derived (this data is currently being submitted for publication). Taken together, this grant has enabled us to fundamentally characterize the functional properties of FA iPS neurons and also to establish the technology to record from genetically modified GFP-expressing cells. Both of these outcomes provide the essential groundwork in establishing a neuronal human cellular model of FA in which there is an urgent need.
A. Typical view of the cultured neurons in the dish. The recording microelectrode can target a selected neuron (asterisk), as identified by the fluorescent label (B).