EXPOSURE TO FORSKOLIN IMPROVES TRANS-DIFFERENTIATION OF BONE MARROW STROMAL CELLS INTO INSULIN PRODUCING CELLS; GENERATING CELLS WITH BETTER RESPONSES TO PHYSIOLOGICAL AND PHARMACOLOGICAL AGENTS

摘要

Several attempts have been made to differentiate stem cells into insulin-producing cells (IPCs) for the treatment of diabetes. Ideally, the differentiation procedures should be simple, repeatable, and must generate cells responsive to physiological and pharmacological stimuli. In this study, we first tested repeatability of a differentiation method for generating IPCs and then tried to improve the method through pharmacological approach to increase capability of IPCs for glucose- and drug-induced insulin secretion. Rat bone marrow stromal cells were trans-differentiated into IPCs by manipulation of the level of glucose, serum and dimethyl sulfoxide (GSD) in culture medium. The effects of addition of nicotinamide (GSD-NA method) and forskolin (GSD-FK method) to differentiation medium on responses of generated IPCs to physiological and pharmacological stimuli were examined. Results demonstrated that the generated IPCs expressed insulin gene and could reduce blood glucose of diabetic mice following intraperitoneal transplantation. When stimulated with glucose as a physiological cue, the IPCs of GSD and GSD-FK methods expressed and secreted insulin in a regulated manner. The expression of insulin gene was also increased in IPCs of GSD-FK method following treatment with glyburide, 3-isobutyl- 1-methylxanthine and forskolin. In conclusion, the GSD method is a simple and repeatable procedure for generating IPCs and modification of the method by increasing cell cAMP using forskolin enhances responsiveness of them to physiological and pharmacological agents.