ALS Disease Mechanisms
We are using human and mouse pluripotent stem cells and mouse models to study ALS disease mechanisms. Comparative analyses of transcriptome databases have revealed common sets of affected genes in mouse models, cell culture and human biopsies. A major effort in this project is to identify disease phenotypes in motor neurons and astrocytes generated from patient-derived induced pluripotent stem cells.
Sandwich Culture for Studies of Motor Neuron Astrocyte Interactions
Motor neurons are produced from mouse embryonic stem cells derived from ALS mouse models, purified by Fluorescence Activated Cell Sorting, plated on glass coverslips and inverted over a monolayer of astrocytes. By using motor neurons or astrocytes from wild type and mutant mice it is possible to study both cell-autonomous and cell non-autonomous interactions between mutant and wild type motor neurons and astrocytes.
We are interested in the signaling pathways and transcription mechanisms involved in the activation of the interferon-b (IFN-b) gene in response to virus infection. In addition, we study the activation of antiviral genes by IFN.
Model of IKKe-mediated regulation of IFN signaling.
IKKe inhibits formation of GAF complex by phosphorylation of STAT1 at S708. This prevents expression of GAS regulated genes. The STAT1 pool is now biased toward ISGF3 complex formation and gene expression from the IFN-I signaling pathway. ISGF3 can accommodate S708 phosphorylated STAT1. Serine phosphorylated ISGF3 allows complex binding to an IKKe-dependent minimal ISRE. ISGF3 with only tyrosine phosphorylation can be stabilized by additional contacts to a longer ISRE motif, termed the IKKe-independent ISRE.