Induced pluripotent stem (iPS) cells are cells that possess the characteristics
ID: 80634 • Letter: I
Question
Induced pluripotent stem (iPS) cells are cells that possess the characteristics of an embryonic stem cell, yet are derived from differentiated cells. One potential benefit of iPS cells is that they may aid in our understanding of diseases, such as Alzheimer's disease. The hallmarks of Alzheimer's disease are the formation of amyloid plaques in brain tissue (from excess amyloid-B secretion in neurons) and the formation of neurofibrillary tangles in neurons. A complete mechanism of disease progression is still unknown, as live neurons are difficult to remove from patients and culture in vitro and many Alzheimer's studies occur post mortem To determine whether iPS cells are a viable means to study Alzheimer's disease, Israel e al. (srael, M.A., Yuan, S.H., Bardy, C., Reyna, S.M., et al. (2012). Probing sporadic and familial Alzheimer's disease using induced pluripotent stem cells." Nature. 7384: 216-20) generated neurons from fibroblasts derived from Alzheimer's patients. There were two groups of patients, those with familial Alzheimer's, in which there is a genetic component, and those from patients with the much more common sporadic form. a. The researchers generated iPS cells from fibroblasts harvested from Alzheimer's patients through the addition of 4 genes. List the 4 genes and state the general function of the protein products of these genes. c. It is known that amyloid-B secretion (derived from cleavage of APP within the cell) is increased in fibroblasts from patients with familial but not sporadic Alzheimer's. Due to the difficulty in studying neurons in vitro, it is unknown whether this holds true in neurons as well. i. Design an experiment to determine whether amyloid-B secretion is increased in the iPS-derived neurons.Explanation / Answer
a)
d)