Faculty Profiles

 

Current Research: 

Dr. Samuelson’s research program is focused on the development and function of the gastrointestinal system, with particular focus on mechanisms regulating epithelial cell identity. In the stomach and intestine, stem cells continually form and replenish the epithelium throughout the lifespan of the organism. Although the mechanisms regulating epithelial cell fate choice have not been fully elucidated, multiple signaling pathways, including Notch, Wnt and Hedgehog have been shown to influence proliferation and epithelial cell specification. In addition, growth factors and cytokines modulate epithelial cell maturation and function. Our laboratory takes advantage of a number of genetically engineered mouse models to investigate these pathways and their function in gastrointestinal physiology. Training experiences in the laboratory are enhanced through active participation in the “UM Gut Group”, which includes a number of well-funded molecular gastrointestinal research laboratories.

 

Current projects in the Samuelson laboratory are focused on understanding the molecular mechanisms regulating gastric parietal cell formation and function, and the pathophysiological consequences of inflammation in the stomach that are associated with the development of gastric cancer. In addition, we are testing the importance of Notch-regulated basic-helix-loop-helix transcription factors, including Math-1 and Neurogenin-3, for cell fate determination in the intestine. These studies also probe the critical cross-talk between epithelium and mesenchyme that regulates cell differentiation and function.

 

Representative Publications:

Lopez-Diaz, L., K.L. Hinkle, R.N. Jain, Y. Zavros, C.S. Brunkan, T. Keeley, K.A. Eaton, J.L. Merchant, C.S. Chew, and L.C. Samuelson.  Parietal Cell Hyperstimulation and Autoimmune Gastritis in Cholera Toxin Transgenic Mice.  Amer. J. Physiol-Gastrointest. Liver Physiol. 290:G970-979 (2006).

 

Jain, R.N, and L.C. Samuelson.  Differentiation of the gastric mucosa.  II. Role of Gastrin in Gastric Epithelial Cell Proliferation and Maturation. Amer. J. Physiol. Theme Article 291:G762-G765 (2006).

 

Jain, R.N. and L.C. Samuelson.  Transcriptional Profiling of Gastrin-Regulated Genes in Mouse Stomach.  Physiol. Genomics 29:1-12 (2007).

 

Lopez-Diaz, L., R. Jain, T.M. Keeley, K.L. VanDussen, C.S, Brunkan, D.L. Gumucio, and L.C. Samuelson.  Intestinal Neurogenin 3 Directs Differentiation of a Bipotential Secretory Progenitor to Endocrine Cell Rather than Goblet Cell Fate. Dev. Biol.  309:298-305 (2007).

 

Qiao, X.T., J.W Ziel, W. McKimpson, B.B. Madison, A. Todisco, J.L. Merchant, L.C. Samuelson, and D.L. Gumucio.  Prospective Identification of a Multilineage Progenitor in Murine Stomach Epithelium. Gastroenterology 133:1989-98 (2007).

 

Jain, R.N., A.A. Al-Menhali, T.M. Keeley, J. Ren, M. El-Zatari, X. Chen, J.M. Merchant, T.S. Ross, C.S. Chew, L.C. Samuelson. Hip1r is expressed in gastric parietal cells and is required for tubulovesicle formation and cell survival in mice.  J. Clin.  Invest. 118:2459-70 (2008).

 

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