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Efficient induction of astrocyte-like cells from human embryonic fibroblasts by defined factors

Quist, Ella LU (2016) KBK820 20161
Pure and Applied Biochemistry
Abstract
Direct cell reprogramming converts fully differentiated cells into other cell types by forced expression of defined sets of cell-type specific transcription factors (TFs). This enables studies of biological processes and disease mechanisms in neural cells that today are hampered by limited accessibility of human tissue. Astrocytes are crucial for brain function and their dysfunction is associated with a wide range of CNS disorders and pathologies. Here, we present an efficient protocol to directly convert human embryonic fibroblasts to astrocyte-like cells. The TFs SOX9, NFIA and NFIB induced expression of the astrocytic markers S100B and/or GFAP. NFIB was essential for expression of GFAP and might drive subtype-specification, activation... (More)
Direct cell reprogramming converts fully differentiated cells into other cell types by forced expression of defined sets of cell-type specific transcription factors (TFs). This enables studies of biological processes and disease mechanisms in neural cells that today are hampered by limited accessibility of human tissue. Astrocytes are crucial for brain function and their dysfunction is associated with a wide range of CNS disorders and pathologies. Here, we present an efficient protocol to directly convert human embryonic fibroblasts to astrocyte-like cells. The TFs SOX9, NFIA and NFIB induced expression of the astrocytic markers S100B and/or GFAP. NFIB was essential for expression of GFAP and might drive subtype-specification, activation or level of maturity. The signaling molecules CNTF, LIF, BMP-4 and dbcAMP promoted astroglial morphology in converted cells. Following functional confirmation, the protocol presented here has the potential to provide a tool for accurate disease modeling and personalized medicine. (Less)
Popular Abstract
From skin cell to star cell: a new tool for modeling neurological diseases

The cause and progression of many diseases affecting our brains are today poorly understood. A major limitation hampering studies of the underlying disease mechanisms, is that tissue and cells from our brains cannot readily be accessed from living humans. Recent work have shown that it is possible to activate certain genes in skin cells and thus convert them into different kind of cells naturally existing in the brain. This technique provides scientists with a new tool to generate sufficient amounts of brain cells in order to elucidate how disease develops. Identification of what cause the disruption of normal function in the brain enables discovery of new... (More)
From skin cell to star cell: a new tool for modeling neurological diseases

The cause and progression of many diseases affecting our brains are today poorly understood. A major limitation hampering studies of the underlying disease mechanisms, is that tissue and cells from our brains cannot readily be accessed from living humans. Recent work have shown that it is possible to activate certain genes in skin cells and thus convert them into different kind of cells naturally existing in the brain. This technique provides scientists with a new tool to generate sufficient amounts of brain cells in order to elucidate how disease develops. Identification of what cause the disruption of normal function in the brain enables discovery of new potential drugs to treat and even possibly cure patients suffering from neurological diseases. In addition, by isolating skin cells from a patient, converting them into the cell type of interest, the specific response of each individual patient cells to different drugs can rapidly be screened in this model. This would reduce the worrisome time for the patient before an effective medical treatment is found. However, at the moment, this cell conversion technique is not efficient enough for all types of cells in the human brain. One example is the star-shaped astrocyte, the most abundant cell type in the brain and spinal cord.

Astrocytes play crucial roles for normal function of our brain. Without this cell type the delicate balance that allow us to think, control our movements and have memories would be disturbed. They support the nerve cells to properly transmit information, participate in forming the barrier that protect the brain from toxins and provide nutrients essential for the neural tissue. Due to the critical roles these star cells plays, it is not very surprisingly that disruption of their functions have indeed been connected to many diseases and disorders affecting the nervous system, such as amyotrophic lateral sclerosis (ALS), schizophrenia and epilepsy. However, today there is poor knowledge of what causes the alteration of normal astrocyte function and the resulting mechanisms that give rise to disease.

With the rising new technique, direct cell reprogramming, we were able to convert human skin cells to cells highly resembling astrocytes in the lab. This was accomplished by utilizing the main workhorses in our cells, the proteins, to change which genes were being active in the otherwise identical genome of the cells. The skin cells were forced to activate the three particular proteins SOX9, NFIA and NFIB. This set of proteins was able to change the governing gene program from that of a skin cell to that of an astrocyte at a remarkably higher efficiency than has ever been done before.

That the astrocytic gene program was turned on, was confirmed by analyzing the presence of proteins normally building up astrocytes but not skin cells. By observing the cells in the microscope it could be seen that the skin cells, over a time course of three weeks, changed their shape to become more similar to astrocytes. This was especially obvious when some additional molecules, that are involved in forming astrocytes during our development, were added.

The next step is now to test if the obtained astrocyte-like cells can carry out the functions performed by astrocytes in the brain. If so, scientists would be provided with a model system to study how the astrocytes' functions have changed, and the reason for this, in different neurological diseases that can only be detected in astrocytes. In addition to potentially identify new drugs and enable personalized medicine these stars could ultimately be used to replace malfunctioning astrocytes in the brain and thus potentially help to cure the patient. (Less)
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author
Quist, Ella LU
supervisor
organization
course
KBK820 20161
year
type
H2 - Master's Degree (Two Years)
subject
keywords
disease modeling, Direct cell reprogramming, astrocytes, neuroscience, applied biochemistry, tillämpad biokemi
language
English
id
8876883
date added to LUP
2016-06-17 11:48:57
date last changed
2016-06-17 11:48:57
@misc{8876883,
  abstract     = {Direct cell reprogramming converts fully differentiated cells into other cell types by forced expression of defined sets of cell-type specific transcription factors (TFs). This enables studies of biological processes and disease mechanisms in neural cells that today are hampered by limited accessibility of human tissue. Astrocytes are crucial for brain function and their dysfunction is associated with a wide range of CNS disorders and pathologies. Here, we present an efficient protocol to directly convert human embryonic fibroblasts to astrocyte-like cells. The TFs SOX9, NFIA and NFIB induced expression of the astrocytic markers S100B and/or GFAP. NFIB was essential for expression of GFAP and might drive subtype-specification, activation or level of maturity. The signaling molecules CNTF, LIF, BMP-4 and dbcAMP promoted astroglial morphology in converted cells. Following functional confirmation, the protocol presented here has the potential to provide a tool for accurate disease modeling and personalized medicine.},
  author       = {Quist, Ella},
  keyword      = {disease modeling,Direct cell reprogramming,astrocytes,neuroscience,applied biochemistry,tillämpad biokemi},
  language     = {eng},
  note         = {Student Paper},
  title        = {Efficient induction of astrocyte-like cells from human embryonic fibroblasts by defined factors},
  year         = {2016},
}