A GRAVES' DISEASE FINGERPRINT REVEALED BY RNA-SEQ OF ~15,000 GENES

Presentation Number: OR28-2
Date of Presentation: June 16th, 2013

Xiaoming Yin*1, Ravi Sachidannandam2, Rauf Latif1 and Terry F Davies1
1Mount Sinai School of Medicine and the James J Peters VA Medical Center, New York, NY, 2Mount Sinai School of Medicine, New York, NY

Abstract

The immune response in autoimmune thyroid disease has been shown to occur primarily within the thyroid gland where the most abundant antigens can be found.  A variety of capture molecules are known to be expressed by thyroid epithelial cells and serve to attract and help retain an intra-thyroidal immune infiltrate which likely exacerbates and prolongs the immune disease.  In order to explore the entire repertoire of expressed genes in human thyroid tissue we have used whole transcriptome shotgun sequencing (referred to as RNA-seq). This approach uses high-throughput sequencing to analyze all the cDNAs prepared from a sample's RNA content.  We have applied this approach to thyroid tissue from 9 patients with hyperthyroid Graves’ disease subjected to total thyroidectomy and compared the data with 12 samples of normal thyroid tissue obtained from patients having a thyroid nodule removed. The expression for each gene was calculated from the sequencing data by taking the median of the coverage across the length of the gene and normalizing the expression levels using quantile normalization and Spearman Rank Correlation for genes with appreciable coverage (at the 25th percentile level) and eliminating the lowly expressed genes.  We also used these distances to cluster the data and determine outliers allowing us to exclude 1 Graves’ disease sample and 2 normal samples. Using this approach we identified 1,967 genes expressed in thyroid tissue out of the 14,890 genes analyzed. Furthermore, 330 genes showed a major increase (>25%) in Graves’ disease and 255 genes showed a major decrease (<75%) in Graves’ disease when compared with normal thyroid tissue. Of particular interest in the repertoire analysis was the clear evidence for over-expression of the antigen presentation pathway with many HLA and associated genes expressed, a clear oxidative stress response revealed and evidence for the primary importance of the chemokine CCL2 involved in the attraction of intra-thyroidal dendritic cells.  This advanced next generation sequencing approach offers unique insights into the immunopathology of autoimmune thyroid disease. (Supported by NIH-DK052464)

 

Nothing to Disclose: XY, RS, RL, TFD