U.S. Department of Health and Human Services
 

 Contact Info

 
Tel: 301-594-3550
Email: seiy@mail.nih.gov
 

 Select Experience

 
  • Ph.D.Kurume University School of Medicine, Japan1988
  • M.D.Kurume University School of Medicine, Japan1983
 

 Related Links

 

Yoshitasu Sei, M.D., Ph.D.

Staff Scientist, Gastroenterology SectionDigestive Disease Branch
Specialties
  • Cancer Biology
  • Cell Biology/Cell Signaling
  • Molecular Biology/Biochemistry
  • Stem Cells/Induced Pluripotent Stem Cells
Research Summary/In Plain Language

Research Summary

Research Goal

Our goal is to understand cellular and molecular biological mechanisms of differentiation and tumorigenesis of enteroendocrine cells.​

Current Research

Our research focuses on investigating cellular and molecular biological mechanisms of differentiation and tumorigenesis of enteroendocrine cells.  We mainly use transgenic mouse models and the ex-vivo organoid system for the investigations.  We have recently identified a novel subset of enteroendocrine cells that express stem cell markers Lgr5, CD133, and DCAMKL1 at the crypt base in the intestine.  Unlike the majority of enteroendocrine cells that differentiate and migrate up to the villi, this subset expresses both stem and mature endocrine markers.  By tracing GFP+ cells in the organoid system, we found that this subset appears around the +4 position in the crypt and migrates down to the crypt base where intestinal stem cells reside between the Paneth cells.  The aims of our investigations are to find 1) what specific physiological function and property this subset of enteroendocrine cells possess compared with the cells that differentiate with upward migration, and 2) if these stem marker-expressing enteroendocrine cells, which reside where Wnt signaling is constantly active, are susceptible to the tumorigenesis.

Applying our Research

The research on endocrine cells in the intestine has been subjected to potential new drug discoveries and therapeutics for diseases widely affecting public health including obesity, diabetes, and digestive diseases such as irritable bowel syndrome and neuroendocrine tumors.

Need for Further Study

Further studies are needed to understand how cell molecular signaling and chromosome remodeling cooperate to regulate cell fate and differentiation.