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Science Fixes ALL THE THINGS
Mar. 9th, 2012 02:12 pmSeminar yesterday was a researcher talking about his work on TRP channels (pronounced "trip"). These allow calcium (II) ions through membranes in response to certain signals. In neural cells, this sets of the depolarization wave that is how you think, so obviously is is very important.
The scientist was using fruit flies as a model, because messing with fruit fly genes is not ferociously unethical and gives a better idea of how these things work. They turn out to be involved in sensing, sending the signals to the brain that say, "there is green light" or "this thing is hot." It turns out that they are a two-part system. The first part responds to toxic things, tells the flies to avoid them, and does not ever change. The second part responds to non-toxic things, and can be changed. We think this is why poisonous things always taste bad but things like stinky cheese and natto can be delicacies.
The other thing is diseases that happen when TRP channels do not work. A lot of them are embryonic lethal - the animal dies very early in development. But some of them cause problems that Mom can take care of, so the baby is fine until they are born. This is the case with mucolipidosis type IV, a horrible disease which prevents lysosomes from working properly. They usually digest broken cell-bits, but when they cannot, the broken bits keep producing poison, eventually bursting the lysosome and killing the cell. Worse, the dead cell spreads the poison to all the cells next door, which also die and spread their poisons, and so on. So when people are born with this, their clock is ticking so quickly that they cannot even learn to speak, because they don't have enough of that type of brain cell left to learn when they get to that age.
So! As with many human proteins, there is a mouse analog which does the same thing and is related evolutionarily. We creepy sciency people found this analog and turned it off, thus successfully giving the mice mucolipidosis type IV. Then we began prodding at the mice to see what we can learn.
What we learned was thusly: you can only fully reverse the disease by turning the gene back on. But you can mostly reverse it by giving the mouse a few hundred phagocytes, which are cells that wander around looking for cells displaying "I am about to die!" signals and then eating them and degrading them. In the disease mice, of course, their phagocytes stop at the degrading them step like every other cell in their bodies, so it is no good using their cells. Phagocytes, though, are a type of white blood cell - meaning that giving the mice a simple white blood cell transfusion from a compatible mouse is able to significantly rescue them.
In people, this would be impractical, of course. The patient would need to have a constant supply of said cells, since mature white blood cells only live about nine hours. We have endless supplies of donor mice and we can quickly breed more, so it is not a problem for them; but finding a compatible human donor willing to be constantly having their blood sucked . . . However, you can give the sick mice a supply of donor bone marrow, which will produce enough healthy phagocytes to keep them healthy, at least for nine months. (After the nine months, the thing we did to kill all of the disease mouse's own bone marrow so it would accept the new marrow tends to kill the mice. Bummer.)
In humans, of course, the science of killing people's bone marrow and replacing it is well known and cures cancer. Now, apparently, it will also cure another deadly thing for which there is, otherwise, no effective cure.
Science!
The scientist was using fruit flies as a model, because messing with fruit fly genes is not ferociously unethical and gives a better idea of how these things work. They turn out to be involved in sensing, sending the signals to the brain that say, "there is green light" or "this thing is hot." It turns out that they are a two-part system. The first part responds to toxic things, tells the flies to avoid them, and does not ever change. The second part responds to non-toxic things, and can be changed. We think this is why poisonous things always taste bad but things like stinky cheese and natto can be delicacies.
The other thing is diseases that happen when TRP channels do not work. A lot of them are embryonic lethal - the animal dies very early in development. But some of them cause problems that Mom can take care of, so the baby is fine until they are born. This is the case with mucolipidosis type IV, a horrible disease which prevents lysosomes from working properly. They usually digest broken cell-bits, but when they cannot, the broken bits keep producing poison, eventually bursting the lysosome and killing the cell. Worse, the dead cell spreads the poison to all the cells next door, which also die and spread their poisons, and so on. So when people are born with this, their clock is ticking so quickly that they cannot even learn to speak, because they don't have enough of that type of brain cell left to learn when they get to that age.
So! As with many human proteins, there is a mouse analog which does the same thing and is related evolutionarily. We creepy sciency people found this analog and turned it off, thus successfully giving the mice mucolipidosis type IV. Then we began prodding at the mice to see what we can learn.
What we learned was thusly: you can only fully reverse the disease by turning the gene back on. But you can mostly reverse it by giving the mouse a few hundred phagocytes, which are cells that wander around looking for cells displaying "I am about to die!" signals and then eating them and degrading them. In the disease mice, of course, their phagocytes stop at the degrading them step like every other cell in their bodies, so it is no good using their cells. Phagocytes, though, are a type of white blood cell - meaning that giving the mice a simple white blood cell transfusion from a compatible mouse is able to significantly rescue them.
In people, this would be impractical, of course. The patient would need to have a constant supply of said cells, since mature white blood cells only live about nine hours. We have endless supplies of donor mice and we can quickly breed more, so it is not a problem for them; but finding a compatible human donor willing to be constantly having their blood sucked . . . However, you can give the sick mice a supply of donor bone marrow, which will produce enough healthy phagocytes to keep them healthy, at least for nine months. (After the nine months, the thing we did to kill all of the disease mouse's own bone marrow so it would accept the new marrow tends to kill the mice. Bummer.)
In humans, of course, the science of killing people's bone marrow and replacing it is well known and cures cancer. Now, apparently, it will also cure another deadly thing for which there is, otherwise, no effective cure.
Science!
