Growing new neurons
In the body, neurons grow in what's called an extracellular matrix (ECM), a protein-rich scaffold that provides cells with nutrients and a molecular structure in which to grow. To grow neurons in the lab, scientists try to mimic the ECM present in the body. Laminin is a common protein in the body's ECM, and studies have shown that laminin aids the growth of neurons from the peripheral nervous system (nerve cells that grow outside the brain and spinal cord).
It was largely assumed, Kim said, that because laminin was good for growing peripheral nerve cells, it would also be good for growing central nerve cells. That turns out not to be the case.
Kim was inspired to test the effects of apoE4 by a previous study that found that a mixture of apoE4 and laminin promoted CNS cell growth better than laminin alone. "The previous work hadn't tested the effects apoE4 by itself," Kim said. "So we started working on a side-by-side comparison of apoE4 and laminin."
Kim and his colleagues cultured rat hippocampal cells a model for mammalian CNS neurons in four different treatments: laminin, laminin and apoE4 mixed, apoE4 alone, and bare glass. They found that cells cultured in apoE4 alone performed substantially better than any other treatment. The apoE4 cells were more likely to adhere to the protein scaffold, which is necessary for proper growth. They also showed more robust growth of axons and dendrites, the wire-like appendages that enable neurons to send and receive nerve signals.
Laminin doesn't seem to be of much benefit at all for culturing CNS cells, according to the study. Cells cultured on laminin alone did not perform any better than cells cultured on bare glass.
That was another big surprise, Kim sa
|Contact: Kevin Stacey|