University of California, Los Angeles
Grant: $30,427 - National Institutes of Health - May. 21, 2009
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Award Description: Characterization of Small Molecule Splicing Modulators of MAPT and FGFR1. We have developed a high-throughput screening method that identifies small molecule modulators of alternative splicing events. The aims are to identify and characterize small molecule modulators of the splicing of MAPT and FGFR1 gene transcripts. Aberrant alternative splicing of these gene transcripts contributes to a disease process that characteristically occurs in the aging population. MAPT-containing neurofibrillary tangles are characteristic pathologic findings in a large number of neurological diseases that contain dementia as a key component. These include frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17), Alzheimer's disease (AD), and dementia puglistica. In each of these cases, accumulation of pathologic MAPT-microtubule tangles correlates with increasing dementia. Indeed, a subset of senile dementia is characterized pathologically only by presence of neurofibrillary tangles. MAPT function is regulated by the inclusion of exon 10 in its mRNA. Increased exon 10 inclusion can promote neurofibrillary tangle formation. FTDP-17 causing mutations in and around exon 10 promote its inclusion. Importantly, exon 10 inclusion also increases in other MAPT-related dementias, such as AD, in the absence of MAPT mutations. This implies that MAPT splicing regulation has changed in aging-related dementia, and perhaps has the potential to be therapeutically targeted. A similar switch in FGFR1 splicing has been shown to play a role in the progression of glioblastoma tumors. Glioblastoma is primarily a disease of the aging population, increasing in incidence more than 10 fold after the age of 50. The alternative a-exon is aberrantly excluded in many glioblastoma cells, and yields an isoform of the receptor which is more responsive to growth factor signaling. Specific treatment of the MAPT and FGFR1 aberrant splicing events by small molecules represents a novel mechanism to reverse a pathologic splicing regulation change that can occur during the aging process. The methods described in this proposal will set forth a standard process for target identification and mechanism characterization for such small molecules.
Project Description: Previous work in our lab identified small molecules that regulate splicing of non-mutated MAPT-exon 10 including digoxin, a cardiotonic steroid. We used bioinformatics methods to analyze the specificity of cardiotonic steroids for MAPT-exon 10, and to provide insight into the mechanism by which they regulate alternative splicing. These studies implicated a specific splicing factor, Tra2-beta, in regulation of digoxin-responsive exons. We found that cardiotonic steroid treatment depletes Tra2-beta in a dose dependent manner. Further analysis revealed that SRp20, another splicing factor, is similarly depleted, and that protein levels of other splicing factors are largely unaffected. Current work focuses on determining the extent to which depletion of Tra2-beta and SRp20 accounts for cardiotonic steroid induced alternative splicing changes. These analyses of the cardiotonic steroids will yield insight into the regulatory pathways that govern exon 10 splicing, and perhaps identify components of these pathways with potential as drug targets. We believe that this work will enhance our understanding of what biological processes promote MAPT-related dementia in the aged population. In the second aim we plan to screen for small molecule regulators of FGFR1 splicing. Though most work to date has focused on the first aim of this grant, we have created a stable HEK293 cell line that expresses a dual-fluorescence FGFR1 splicing reporter. This line reliably replicates known FGFR1 splicing regulation, and is suitable for high throughput small molecule screens. We will perform a pilot drug screen which will later be expanded to identify families of small molecules that regulate FGFR1 alternative splicing. We will then apply the methods that are developed in Aim 1 to identify the targets and characterize the mechanism of alternative splicing regulation by potentially therapeutic small molecules.
Jobs Summary: UCLA is a world-class educational institution in the midst of an unprecedented financial crisis that threatens our mission to provide education, research and public service benefiting millions of people. ARRA funding to the University has enabled the creation and retention of jobs to support vital scientific research and training activities that would otherwise be severely constrained or eliminated through budget cuts. The type(s) of jobs created and retained by this ARRA-fund award includes: Scientific/Technical Professionals and Staff positions, such as Researchers, Post-Docs, Graduate Student Researchers, Project Managers and Statisticians. (Total jobs reported: 1)
Project Status: Less Than 50% Completed
This award's data was last updated on May. 21, 2009. Help expand these official descriptions using the wiki below.
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