| First Author | Duckworth CA | Year | 2009 |
| Journal | Gastroenterology | Volume | 136 |
| Issue | 3 | Pages | 943-52 |
| PubMed ID | 19185578 | Mgi Jnum | J:146852 |
| Mgi Id | MGI:3838680 | Doi | 10.1053/j.gastro.2008.11.036 |
| Citation | Duckworth CA, et al. (2009) Suppression of apoptosis, crypt hyperplasia, and altered differentiation in the colonic epithelia of bak-null mice. Gastroenterology 136(3):943-52 |
| abstractText | BACKGROUND & AIMS: Members of the bcl-2 family of proteins are important determinants of cell fate. Bcl-2 and bcl-w have previously been identified as antiapoptotic members of this family that promote gastrointestinal epithelial cell survival. However, a proapoptotic family member that exerts important effects in the gastrointestinal tract has not yet been identified. We have therefore investigated intestinal epithelial apoptosis in bak-null mice. METHODS: Apoptosis, mitosis, differentiated cell composition, and cell number were assessed on a cell positional basis in the small intestinal and colonic epithelia of bak-null mice and their C57BL/6 wild-type counterparts. Apoptosis was induced by 1-Gy gamma-irradiation or 10mg/kg azoxymethane (AOM). Aberrant crypt foci were induced by 3 weekly injections of 10mg/kg AOM. RESULTS: The amount of spontaneous apoptosis in the colonic intercrypt table was reduced, and colonic crypt cell number and mitotic index were elevated in bak-null mice relative to C57BL/6 wild-type mice. Bak-null colonic crypts contained more goblet cells and fewer endocrine cells than those from C57BL/6 mice. Fewer colonic epithelial apoptotic cells were observed after gamma-radiation and AOM in bak-null mice, and these mice also displayed greater numbers of colonic AOM-induced aberrant crypt foci. None of these parameters differed in the small intestinal epithelium of bak-null mice compared with C57BL/6. CONCLUSIONS: Bak prevents colonic crypt hyperplasia by regulating spontaneous apoptosis at the colonic intercrypt table region and also regulates damage-induced apoptosis in the colonic crypt. Deletion of bak in vivo results in altered colonic proliferation and differentiation, and causes increased susceptibility to colonic carcinogenesis. |
