U-M scientists find new causes for neurode...(ch. Building on research from Meisler a ...),Health

Building on research from Meisler, a mouse geneticist, and Weisman, a yeast geneticist, the collaborators published a paper in Nature, July 5, 2007, showing that in mice, the FIG4 gene is required to maintain normal levels of the signaling lipid and to maintain a normal nervous system. Importantly, they found that human patients with a very minor defect in their FIG4 genes had serious neurological problems.

The signaling lipid PI(3,5)P2 (short for phosphatidylinositol 3,5-bisphosphate) is part of a communication cascade that senses changes outside the cell and promotes actions inside the cell to accommodate to the changes.

Weisman's team found that mice missing the VAC14 gene, which encodes a regulator of PI(3,5)P2 levels, suffer massive neurodegeneration that looks nearly identical to the neurodegeneration seen in the FIG4 mutant mice. In both cases the levels of PI(3,5)P2 are one half of the normal levels. The fact that both mice have half the normal levels of the lipid and also have the same neurodegenerative problems provides evidence that there is a direct link between the lipid and neuronal health.

The new findings indicate that when Vac14 is removed, the cell bodies of many of the neurons appear to be empty spaces and the brain takes on a spongiform appearance.

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