[760] Expression Profiling of Collagenous Colitis in Colonic Epithelium by Laser Capture Microdissection and PCR Array

BJ Winn, KT Sciandra, P Meitner, R Tavares, MB Resnick. Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI

Background: Collagenous colitis (CC) is a disorder characterized by band-like subepithelial collagen deposition. Although the histopathological features of CC are well characterized the pathophysiology of this disorder remains uncertain. Relatively few studies have examined the expression of genes and proteins that play a role in extracellular matrix formation and degradation. Our aim was to determine whether expression profiling could identify factors that may contribute to the pathophysiology of CC.
Design: Paraffin blocks from cases of CC and aged matched controls with a history of diarrhea but histologically normal colonic epithelium (NC) were retrieved from the institution's pathology archive. Laser capture microdissection was utilized to separate surface epithelium from the surrounding stroma. RNA was extracted and reverse transcribed using Paradise FFPE reagents from Molecular Devices. The resulting cDNA was used to probe a 'Human Extracellular Matrix and Adhesion molecules' RT² Profiler PCR Array (SuperArray Bioscience Corp, Frederick, MD) for the genetic expression profile of key genes involved in the deposition of subepithelial collagen. Array results were confirmed in additional cases of each type by QPCR.
Results: Two Profiler PCR arrays were run for each subgroup (2CC, 2NC). Ten genes were up-regulated and 15 genes were down-regulated two fold or more in the epithelium from laser-captured collagenous colitis as compared with normal colonic epithelium. Representative genes were confirmed by QPCR in 10 further cases of CC and matched controls (see Tables 1 & 2).

Table 1. Down-regulated genes:

Genes	ADAMTS1	LAMA2	ADAMTS13	SPP1	THBS1	MMP13	VCAN
Fold change	-2.09	-2.15	-2.27	-2.58	-2.7	-2.99	-3.49

Table 2. Up-regulated genes:

Genes	ITGAL	COL12A1	MMP9	MMP3	SELP	MMP12	MMP10
Fold Change	2.03	2.56	3.94	4.86	5.03	6.25	6.68

Conclusions: All of the up-regulated and down-regulated genes in the array are factors known to be involved in inflammation, fibrosis, or extracellular matrix formation/degradation. Expression profiling by laser capture microdissection of archival pathology specimens is a novel technique by which to identify genes involved in the pathophysiology of microscopic colitis.
Category: Gastrointestinal

Wednesday, March 24, 2010 9:30 AM

Poster Session V # 58, Wednesday Morning