According to a study published in the February 18 journal Science, some neurons in adult mouse's brain created the characteristics and physiological of the characteristics and physiological of nearby astrocytes. McGill University researchers and colleagues identified that it is molecular signal called sonic hedgehog (Shh) secreted by the neurons that contributes to these changes.
Ed Ruthazer (not involved in the study), neurologist at Montreal Neurological Institute of McGill University, said, "What extremely excited us of this paper is that the fate of a cell may be decided by its interaction with neighbors after it has established its morphology and location in brain. This conversion is not trivial, for it seems to fundamentally recombine the cell's transcriptome."
Astrocytes are non-neuronal cells in the central nervous system. They support and regulate the function of neurons. In 2013, researchers at Duke University demonstrated that astrocytes are essential to stop bleeding after a stroke or brain injury and promote repair. Neuroscientists at Stanford University School of Medicine confirmed that the astrocytes may actively remove synaptic nerve cell circuits by selectively trimming. In 2014, researchers at the University of California, San Francisco reported, malfunctioning astrocytes may contribute to amyotrophic lateral sclerosis (ALS) and this kind of neurodegenerative diseases, and even autism and schizophrenia and other developmental disorders. Swedish scientists have confirmed that in the damage parts of the brain, astrocytes can form immature nerve cells, and then they develop into mature nerve cells.
There are various astrocytes in mammalian brain performing a variety of specialized functions. Keith Murai, the new study's lead author from McGill University, said that this diversity is largely thought to be formed in embryonic development and early development after birth. "But after that, it is believed that some characteristics of these cells are cured in their later life."
However, MuraiI and his colleagues took a different view. "Some neural circuits around astrocytes are so specialized. It is difficult to imagine that all the decisions of these cells' characteristic in this time of development. After all, the neural circuits themselves fully form until much later."
In order to investigate whether it is possible that the astrocytes continue to shape, Murai research team searched for possible control of the gene product in the continuing development of adult neurons and astrocytes. To simplify the problem, the researchers put the focus on the cerebellar cortex. There are only two types of astrocytes in this region: Bergmann glial cells which surrounds the Purkinje cells (PCs) nerve impulses receiving area; velate astrocytes (VAs), which surrounds the granulosa cells (GCs). Their results revealed a number of candidate factors, and there is a signal path emerges: Shh signal.
Murai explained, Shh is known to play an important role in many developmental form factors in the development of embryos occurs, including the impact of brain cells specialized. "People used to think that after the completion of the development of this signaling pathway in the brain will be closed and removed, but the new study confirmed even in the adult brain in this signaling pathway remains very potent."
The researchers found that the PC is the cerebellum neurons generated protein Shh; Shh receptor abundantly expressed in BG instead VA cells.
In addition, BGs need Shh signal from PCs to maintain their identity. When the researchers used transgenic technology closed in the adult mouse brain PCs generated or Shh Shh signaling in BGs, BG and Vas cells using similar transcriptional profiling. On the other hand, if the enhanced Vas Shh signaling, these cells will become more like BGs.
"We almost can Shh signal level one type of astrocyte exchange said another. It’s not just involving a small number of factors, in response to this signaling pathway genes turn on or off the hundreds." Murai said.
The research team also found evidence that, Shh controls can also affect other areas of the brain astrocytes, changing these cells electrophysiology.
Cell biologist at Duke University Cagla Eroglu (not involved in the study) said: "The most important point is that the fate of astrocytes molecule is not fixed." Shape of these cells does not seem to have plasticity. Despite the impact of Shh signaling and electrical behavior of the expression profile of astrocytes, cell morphology remained unchanged.
Cagla said, the finding that astrocytes have greater plasticity than previously thought is "exciting and interesting, but still needs to determine its precise function of this phenomenon according to the animal's behavior or learning ability."
Go through this link to know more: http://www.cusabio.com/ELISA-Kit/Rabbit-Vascular-endothelial-growth-factor-receptor-1FLT1-ELISA-kit-1035338.html
没有评论:
发表评论