Our technology is based on the groundbreaking discovery of Dr. Domenico Accili that inhibition of FOXO1 in specific gut cells leads to their conversion into glucose-regulated insulin-producing cells.
This work was first published in Nature Genetics in 2012, and later extended in a 2014 Nature Communications publication. We have demonstrated the feasibility of chemically modifying FOXO function using small molecules that selectively modulate FOXO activity to achieve therapeutic effects.
Targeted deletion of FOXO1 in enteroendocrine cells produces beta-like cells that are glucose-responsive. Unlike embryonic stem cell-derived beta cells, the converted gut cells show glucose dose-dependent release of insulin that bodes well for their therapeutic potential. That is to say, they release insulin in proportion to the amount of glucose to which they are exposed, just like pancreatic beta cells. Moreover, these gut insulin+ cells can reverse hyperglycemia in a mouse model with chemically induced diabetes, taking over the function of the endocrine pancreas.
In human gut tissue, FOXO1 is mostly expressed near the bottom of the crypt, where cells arising from gut stem cells localize. FOXO1 expression co-localizes with serotonin (5HT) expression. 5HT cells in the gut are the largest source of serotonin outside the central nervous system. Their physiologic function is unclear. Evidence suggests that 5HT cells become insulin-producing cells upon inhibition of FOXO1. However, the reduction in 5HT-expressing cells upon FOXO inhibiton is modest, allaying concerns of adverse effects secondary to reduced gut-derived 5HT. FOXO1 inhibition using either a dominant-negative mutant adenovirus or lentivirus-encoded shRNA generated insulin-positive cells in human iPS cell-derived gut organoids. These cells express all of the markers of mature beta cells, are mono-hormonal, release c-peptide in response to secretagogues, and survive in-vivo following transplantation.
While targeting intestinal cells for conversion to insulin producing cells may at first seem surprising, hormone producing (enteroendocrine) cells in the gut are developmentally related to pancreatic endocrine cells. In normal development, endocrine cells in the pancreas and gut arise from Ngn3+ progenitor cells. In addition, a common path drives development of both serotonin positive cells in gut (the target of FOXO1 inhibition) and beta cells. FOXO1 inhibition is required for normal beta cell development in human, as well as for mouse pancreas. Thus, the notion that FOXO1 inhibiton is conducive to formation of beta-like cells is consistent with developmental findings. Enteroendocrine cells possess the machinery required to manufacture, package, and release hormone; thus, they are “primed” to be converted into another endocrine cell type. 5HT+ cells occur frequently in the gut and are continuously replenished by normal cellular turnover mechanisms from progenitor cells. Moreover, enteroendocrine cells are by nature “plastic,” i.e., they are not committed to a specific lineage and to the production of a single hormone to the same extent as endocrine cells in other organs. Thus, our approach aims to leverage the unique property of this cell population to create a novel niche for insulin production by targeted cell conversion.
Fanny Langlet, Rebecca A. Haeusler, Daniel Lindén, Elke Ericson, Tyrrell Norris, Anders Johansson, Joshua R. Cook, Kumiko Aizawa, Ling Wang, Christoph Buettner, Domenico Accili
Cell · Volume 171, Issue 4, p824–835, 2 November 2017FOXO1 inhibition yields functional insulin-producing cells in human gut organoid cultures
Ryotaro Bouchi, Kylie S. Foo, Haiqing Hua, Kyoichiro Tsuchiya, Yoshiaki Ohmura, P. Rodrigo Sandoval, Lloyd E. Ratner, Dieter Egli, Rudolph L. Leibel & Domenico Accili
Nature Communications · 5, Article number: 4242 · 30 June 2014Generation of functional insulin-producing cells in the gut by Foxo1 ablation
Chutima Talchai, Shouhong Xuan, Tadahiro Kitamura, Ronald A DePinho & Domenico Accili
Nature Genetics · 44, pages 406–412 · 11 March 2012