I don’t know if you’re familiar with the cinematic gem Deep Blue Sea, but as far as ridiculous neuroscience sci-fi horror movies go, it is awesome. Let me summarize the plot for you. A group of researchers is working in an underwater lab trying to cure Alzheimer’s. Their proposal involves genetically engineering three Mako sharks to enlarge the size of their brains. Somehow, the researchers plan to harvest these huge brains and then use the tissue to cure Alzheimer’s… Lets just say, they didn’t cure Alzheimer’s and spoiler! Samuel L. Jackson gets eaten in one of cinema’s greatest death scences.
It turns out that not all neuroscientists are familiar with Deep Blue Sea and the consequences of tinkering around with their lab animal’s brains. A new study recently published in Cell Stem Cell, discovered that when human glial progenitor cells are grafted into mouse’s brains the mice become “smarter”. A glial progenitor cell is a type of stem cell that is capable of maturing into an astrocyte, which is a cell that supports neurons, and is the most abundant type of cell in the brain. These human astrocytes distributed evenly throughout the brain of the recipient mouse and even generated their typical structures which previously had only been observed in humans and apes.
Astrocytes don’t normally participate in the electrical activity of the brain but they do send signals via fluctuations of calcium. These human astrocytes respond to changes in calcium level much faster than mouse astrocytes. These quick responses to calcium enhance how the mouse neurons signal electrically. After observing these physical changes in the chimeric human-mouse brains, the next question is, do these changes change how well the mouse brain functions?
The mice participated in several classic learning and memory tests, auditory fear conditioning, contextual fear conditioning, Barnes mazes, and Object-location memory tasks. On every test, the mice with human glial cells outperformed control mice. So it appears that adding these glial cells has made these animals “smarter”.
If I were those researchers, I would be a little worried about my lab mice turning on me. At least they can’t run 35 mph or have enormous jaws….yet.