immune molecules in the brain
Posted: Tue Mar 31, 2009 7:23 am
I think maybe it is from an unexpected basic research finding like this that we will make significant progress in understanding MS.
Workhorse immune molecules lead secret lives in the brain
March 30, 2009 - Molecules assumed to be in the exclusive employ of the immune system have been caught moonlighting in the brain - with a job description apparently quite distinct from their role in immunity.
Carla Shatz, PhD, professor of neurobiology and of biology, and her colleagues at the Stanford University School of Medicine have shown that members of a large family of proteins critical to immune function (collectively known as HLA molecules in humans and MHC molecules in mice) also play a role in the brain. "We think that this family of molecules has an important role in learning and memory," Shatz said. Surprisingly, the absence of one or another of them in the brain can trigger improved motor learning, although perhaps at the expense of other learning ability.
The study will be published online on March 30 in the journal Proceedings of the National Academy of Sciences.
The proteins in question sit like jewel cases on the outer surfaces of most cells in the body, displaying fragments of the cell's innards, called peptides, to best advantage for window-shopping by roving inspectors called T-cells. When a T-cell "sees" a peptide with an aberrant chemical sequence - a sign of possible infection or cancer - it can attack the aberrant cell directly or alert the immune system, which responds with a vengeance.
It was long thought that MHC molecules are found on the surfaces of brain cells only when the brain suffers injury or infection. But that picture was altered several years ago when a group led by Shatz compared gene expression in normally reared mice and another group that had been deprived of visual stimuli. In particular, they looked at a region of the brain that processes visual input. "Completely unexpectedly, we found that one of the genes needing input from the eye in order to be expressed encodes an MHC molecule," said Shatz.
and later in the article...
The Stanford researchers have found other MHC molecules expressed in other types of neurons in other parts of the brain. "These molecules keep showing themselves to be important in limiting how much circuits can change by strengthening or weakening connections between nerve cells. We think they're going to figure as important players in many neurological disorders," Shatz said, noting a tantalizing if still controversial link between immune function and developmental brain disorders such as autism and schizophrenia.
"Traditionally, there's been a kind of provincialism about molecules," she said. "You know, 'Some molecules are used only by the immune system, other ones only by neurons.' But I think the assumption that the immune system would have sole ownership over these molecules is pretty naive.
"We could have ignored this finding. We could have said, 'Well, MHC isn't supposed to be there, so it must be an artifact.' And we would have missed one of the most exciting aspects of doing research, which is the unexpected."
for the whole thing:
http://www.physorg.com/news157653719.html
Workhorse immune molecules lead secret lives in the brain
March 30, 2009 - Molecules assumed to be in the exclusive employ of the immune system have been caught moonlighting in the brain - with a job description apparently quite distinct from their role in immunity.
Carla Shatz, PhD, professor of neurobiology and of biology, and her colleagues at the Stanford University School of Medicine have shown that members of a large family of proteins critical to immune function (collectively known as HLA molecules in humans and MHC molecules in mice) also play a role in the brain. "We think that this family of molecules has an important role in learning and memory," Shatz said. Surprisingly, the absence of one or another of them in the brain can trigger improved motor learning, although perhaps at the expense of other learning ability.
The study will be published online on March 30 in the journal Proceedings of the National Academy of Sciences.
The proteins in question sit like jewel cases on the outer surfaces of most cells in the body, displaying fragments of the cell's innards, called peptides, to best advantage for window-shopping by roving inspectors called T-cells. When a T-cell "sees" a peptide with an aberrant chemical sequence - a sign of possible infection or cancer - it can attack the aberrant cell directly or alert the immune system, which responds with a vengeance.
It was long thought that MHC molecules are found on the surfaces of brain cells only when the brain suffers injury or infection. But that picture was altered several years ago when a group led by Shatz compared gene expression in normally reared mice and another group that had been deprived of visual stimuli. In particular, they looked at a region of the brain that processes visual input. "Completely unexpectedly, we found that one of the genes needing input from the eye in order to be expressed encodes an MHC molecule," said Shatz.
and later in the article...
The Stanford researchers have found other MHC molecules expressed in other types of neurons in other parts of the brain. "These molecules keep showing themselves to be important in limiting how much circuits can change by strengthening or weakening connections between nerve cells. We think they're going to figure as important players in many neurological disorders," Shatz said, noting a tantalizing if still controversial link between immune function and developmental brain disorders such as autism and schizophrenia.
"Traditionally, there's been a kind of provincialism about molecules," she said. "You know, 'Some molecules are used only by the immune system, other ones only by neurons.' But I think the assumption that the immune system would have sole ownership over these molecules is pretty naive.
"We could have ignored this finding. We could have said, 'Well, MHC isn't supposed to be there, so it must be an artifact.' And we would have missed one of the most exciting aspects of doing research, which is the unexpected."
for the whole thing:
http://www.physorg.com/news157653719.html