Effect of Nicotine on the Proliferation and Differentiation of Mouse Induced Pluripotent Stem Cells

The molecular mechanisms that regulate the proliferation and differentiation of induced pluripotent stem (iPS) cells are of great interest. However, whether stimulation with nicotine enhances the proliferation and differentiation of iPS cells has not been investigated. In the present study, western blot analysis revealed that the alpha(4)-nAchR and alpha(7)-nAchR are expressed in mouse iPS cells. Mouse iPS cells were treated with nicotine for 24 h under feeder-free conditions. Mouse iPS cells were guided to differentiate into mesodermal progenitor cells on type IV collagen (Col IV)-coated dishes in differentiation medium. Mouse iPS cells were guided to differentiate into neural progenitor cells by embryoid body (EB) formation on ultra-low-attachment dishes. After 4 days of growth, all-trans retinoic acid (ATRA; 1 mu M) or nicotine (300 nM) was added to the EB cultures and maintained for additional 4 days and plated onto fibronectin-coated plates. A BrdU incorporation assay showed that treatment with 300 nM nicotine significantly increased the DNA synthesis of mouse iPS cells or mouse iPS cell-derived mesodermal progenitor cells. This effect was significantly inhibited by pretreatment with an alpha(4)-nAchR antagonist, an alpha(7)-nAchR antagonist, or a CaMK Pi inhibitor. The differentiation potential of mouse iPS cells into mesodermal progenitor cells or neural progenitor cells was not affected by the nicotine treatment. The present study indicates that stimulation of the alpha(4)-nAchR and alpha(7)-nAchR may lead to a significant increase in the proliferation of mouse iPS cells or mouse iPS cell-derived mesodermal progenitor cells through the CaMK Pi signaling pathway.