Determining the Role of Monocytes in Dextran Sulfate Sodium (DSS)-Induced Colitis

Kassidy M. Spears*, Kelly Monaghan and Edwin Wan, Department of Microbiology, Immunology, and Cell Biology, West

Field (Broad Category): Medical Sciences (Biological & Biochemical Sciences) 

Student’s Major: Biology 

Inflammatory bowel disease (IBD), comprised of Crohn’s disease and ulcerative colitis, is a common disease characterized by chronic inflammation of the gastrointestinal tract. In this study, dextran sulfate sodium (DSS)- induced colitis model in mice is used to study IBD. DSS is toxic to epithelial cells therefore causing erosion and tissue death. Over the past few months we have established a DSS-induced model in the lab. To do this, a 1% DSS drinking water solution was administered to mice for either 4 or 7 days and mice were scored daily on a 5-point scale. Colons were then harvested on either day 4 or 7 and were stained with hematoxylin and eosin (H&E). Pathological score was determined using a six-point scale and based on the extent of tissue damage and immune cell infiltration. In addition, studies have shown that CCR2+ pro-inflammatory monocytes are located in the lamina propria, a thin layer of loose tissue in the colon wall. Moving forward, our research goal is to determine the role of monocytes in DSS-induced colitis, with the hypothesis that monocyte activation exacerbates DSS-induced colitis. This hypothesis can be addressed using genetically manipulated CCR2-red fluorescent protein tagged mice, which lack CCR2. This means that the monocytes in these mice cannot migrate, therefore these mice can be used to study the function of monocytes in DSS-induced colitis by tracking the red fluorescent protein tag. This study is clinically relevant because monocytes may be a potential therapeutic target for treating IBD. 

Funding: School of Medicine Research and Education Office