Protein promotes growth of intestinal epithelium

Researchers have identified a protein called R-spondin1 that appears to play a key role in the renewal of intestinal epithelium cells. As such, R-spondin1 could have therapeutic potential in various gastrointestinal diseases.

As reported in the August 19th issue of Science, Dr. Walter D. Funk, from Nuvelo Inc. in Sunnyvale, California, and colleagues used a transgenic murine model to identify R-spondin1. The protein was found to be a potent and specific promoter of intestinal crypt cell proliferation. Further characterization of R-spondin1 revealed that it contained a thrombospondin domain and was expressed in enteroendocrine cells and in epithelial cells from various tissues. Injection of R-spondin1 into mice produced rapid crypt cell proliferation. Moreover, the process responsible for this proliferation did not seem to be entirely dependent on a previously characterized Wnt-mediated signaling pathway. In a model of chemotherapy-induced intestinal mucositis, pretreatment with R-spondin1 dramatically reduced the diarrhea and weight loss that occurred. Moreover, there was no evidence that this agent compromised the anti-tumor efficacy of the chemotherapy given. Looking forward, “it will be very important to identify receptors for R-spondins to fully understand the biology of this important class of activating ligands,” the authors conclude. (Source: Science 2005;309:1256-1259: Reuters Health: Oncolink: August 2005.)