Mouse bone marrow stromal cells differentiate into functional smooth muscle cells

Abstract

Background: We and others have reported from morphological examination that smooth muscle-like cells may be differentiated from bone marrow stromal cells (BMSCs). However, few studies have addressed whether the differentiated smooth muscle-like cells (BMSC-SMCs) also possess the functional properties of SMCs. We conducted physiological study to characterize BMSC-SMCs. Methods and Results: We assessed voltage-gated Ca²⁺ currents using whole-cell patch clamp methods. Whereas only 10% of BMSC-derived SM progenitor cells showed T-type Ca²⁺ channel current, 40% of BMSC-SMCs showed T-type Ca²⁺ channel current and other 60% showed L-type Ca²⁺ channel current. We also measured agonist-evoked [Ca²⁺]_i transients using Fura-2 imaging. Ca²⁺ transients was observed in BMSC-SMCs in response to SMC-specific agonists such as bradykinin (10⁻⁶ M) and angiotensin II (10⁻⁷ M). Finally, we assessed agonist-evoked contraction using video camera. In response to SMC-specific agonists, BMSC-SMCs showed contraction-like movement, i.e., change in shape and sequential movement. Conclusions: BMSC-SMCs exhibit functional and physiological properties of SMCs. Since BMSCs have the potential to differentiate into functional SMCs, they can be reliable and expandable SMC sources for the construction of tissue-engineered vascular grafts. [J Physiol Sci. 2008;58 Suppl:S112]