Unleashing stem cells power to fix brain damage

(Stem Cells News image)

A QUT scientist is hoping to unlock the potential of stem cells as a way of repairing neural damage to the brain.

Rachel Okolicsanyi, from the Genomics Research Centre at QUT’s Institute of Health and Biomedical Innovation, said unlike other cells in the body which were able to divide and replicate, once most types of brain cells died, the damage was deemed irreversible.

Ms Okolicsanyi is manipulating adult stem cells from bone marrow to produce a population of cells that can be used to treat brain damage.

“My research is a step in proving that stem cells taken from the bone marrow can be manipulated into neural cells, or precursor cells that have the potential to replace, repair or treat brain damage,” she said.

Ms Okolicsanyi’s research has been published in Developmental Biology journal, and outlines the potential stem cells have for brain damage repair.

“What I am looking at is whether or not stem cells from the bone marrow have the potential to differentiate or mature into neural cells,” she said (…)

“What we are hoping is that by manipulating this particular family of proteins we can encourage the stem cells to show a higher percentage of neural markers indicating that they could mature into neural cells rather than what they would normally do, which is form into bone, cartilage and fat,” she said (…)

Ms Okolicsanyi said by doing this, it would be possible to see the different reactions stem cells had to particular chemicals and find out whether these chemicals could increase or decrease the neural markers in the cells.

“The proteins that we are interested in are almost like a tree,” she said.

“They have a core protein that is attached to the cell surface and they have these heparin sulfate chains that branch off.

“So when the chemicals we add influence the stem cell in different ways, it will help us understand the interactions between proteins and the resulting changes in the cell.

“In the short-term it is proof that simple manipulations can influence the stem cell and in the long-term it is about the possibility of increasing the neural potential of these stem cells.”

Ms Okolicsanyi said the big picture plan was to be able to introduce stem cells into the brain that would be able to be manipulated to repair damaged brain cells.

“The idea, for example, is that in stroke patients where the patient loses movement, speech or control of one side of their face because the brain’s electrical current is impaired, that these stem cells will be able to be introduced and help the electrical current reconnect by bypassing the damaged cells.”

read more:qut.edu.au/news/news?news-id=73438

Researchers identify first piece of new brain-repair circuit

Duke researchers have found a new type of neuron in the adult brain that is capable of telling stem cells to make more new neurons. Though the experiments are in their early stages, the finding opens the tantalizing possibility that the brain may be able to repair itself from within (…)

In a study with mice, his team found a previously unknown population of neurons within the subventricular zone (SVZ) neurogenic niche of the adult brain, adjacent to the striatum. These neurons expressed the choline acetyltransferase (ChAT) enzyme, which is required to make the neurotransmitter acetylcholine. With optogenetic tools that allowed the team to tune the firing frequency of these ChAT+ neurons up and down with laser light, they were able to see clear changes in neural stem cell proliferation in the brain (…)

The mature ChAT+ neuron population is just one part of an undescribed neural circuit that apparently talks to stem cells and tells them to increase new neuron production, Kuo said. Researchers don’t know all the parts of the circuit yet, nor the code it’s using, but by controlling ChAT+ neurons’ signals Kuo and his Duke colleagues have established that these neurons are necessary and sufficient to control the production of new neurons from the SVZ niche.

“We have been working to determine how neurogenesis is sustained in the adult brain. It is very unexpected and exciting to uncover this hidden gateway, a neural circuit that can directly instruct the stem cells to make more immature neurons,” said Kuo, who is also the George W. Brumley, Jr. M.D. assistant professor of developmental biology and a member of the Duke Institute for Brain Sciences. “It has been this fascinating treasure hunt that appeared to dead-end on multiple occasions!”

Kuo said this project was initiated more than five years ago when lead author Patricia Paez-Gonzalez, a postdoctoral fellow, came across neuronal processes contacting neural stem cells while studying how the SVZ niche was assembled (…)

“The brain gives up prime real estate around the lateral ventricles for the SVZ niche housing these stem cells,” Kuo said. “Is it some kind of factory taking orders?” Postdoctoral fellow Brent Asrican made a key observation that orders from the novel ChAT+ neurons were heard clearly by SVZ stem cells.

Studies of stroke injury in rodents have noted SVZ cells apparently migrating into the neighboring striatum. And just last month in the journal Cell, a Swedish team observed newly made control neurons called interneurons in the human striatum for the first time. They reported that interestingly in Huntington’s disease patients, this area seems to lack the newborn interneurons.

“This is a very important and relevant cell population that is controlling those stem cells,” said Sally Temple, director of the Neural Stem Cell Institute of Rensselaer, NY, who was not involved in this research. “It’s really interesting to see how innervations are coming into play now in the subventricular zone.”

Kuo’s team found this system by following cholinergic signaling, but other groups are arriving in the same niche by following dopaminergic and serotonergic signals, Temple said. “It’s a really hot area because it’s a beautiful stem cell niche to study. It’s this gorgeous niche where you can observe cell-to-cell interactions.”

These emerging threads have Kuo hopeful researchers will eventually be able to find the way to “engage certain circuits of the brain to lead to a hardware upgrade. Wouldn’t it be nice if you could upgrade the brain hardware to keep up with the new software?” He said perhaps there will be a way to combine behavioral therapy and stem cell treatments after a brain injury to rebuild some of the damage.

The questions ahead are both upstream from the new ChAT+ neurons and downstream, Kuo says. Upstream, what brain signals tell ChAT+ neurons to start asking the stem cells for more young neurons? Downstream, what’s the logic governing the response of the stem cells to different frequencies of ChAT+ electrical activity? (…)

read more:medicalnewstoday.com/releases/277676.php

 

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