Mesenchymal stem cells (MSCs) are a promising cell source for tissue-engineered connective tissue repair strategies. Additionally, increasing evidence confirms the role of the mechanical environment in maintaining tissue homeostasis, with calcium signaling implicated as a mediator in mechanotransduction pathways. Spontaneous intracellular calcium signaling was observed in a subset of MSCs embedded within 4% alginate hydrogel constructs, measured by a Ca2+ indicator fluo-4 in conjunction with confocal laser-scanning microscopy. By the use of pair-wise analysis, it was shown that distinct populations of MSCs up-regulated and down-regulated the frequency of calcium transients with the application of a 20% static uniaxial compressive strain of 20 min duration, delivered after a 20 min unstrained period. Calcium transients in control specimens were monitored throughout two unstrained 20 min periods. These values were statistically significant (p<0.05) by χ2 test of independence. This dual-response indicator highlights the heterogeneous nature of MSC populations, which may have important implications for their successful use in cell therapies.
CarterD.R., BlenmanP.R., BeaupreG.S.Correlations between mechanical stress history and tissue differentiation in initial fracture healing. J Orthop Res1988; 6: 736–48.
LeeD.A., BaderD.L.Compressive strains at physiological frequencies influence the metabolism of chondrocytes seeded in agarose. J Orthop Res1997; 15: 181–8.
4.
LiY.J., BatraN.N., YouL.. Oscillatory fluid flow affects human marrow stromal cell proliferation and differentiation. J Orthop Res2004; 22: 1283–9.
5.
SimmonsC.A., MatlisS., ThortonA.J., ChenS., WangY., MooneyD.J.Cyclic strain enhances matrix mineralization by adult human mesenchymal stem cells via the extracellular signal-regulated kinase (ERK1/2) signalling pathway. J Biomech2003; 36: 1087–96.
6.
CampbellJ.J., LeeD.A., BaderD.L.Dynamic compressive strain influences chondrogenic gene expression in human mesenchymal stem cells. Biorheology2006; 43: 455–70.
7.
HuangC.Y., HagarK.L., FrostL.E., SunY., CheungH.S.Effects of cyclic compressive loading on chondrogenesis of rabbit bone-marrow derived mesenchymal stem cells. Stem Cells2004; 22: 313–23.
8.
BootmanM.D., LippP., BerridgeM.J.The organisation and functions of local Ca(2+) signals. J Cell Sci2001; 114: 2213–22.
9.
KnightM.M., RobertsS.R., LeeD.A., BaderD.L.Live cell imaging using confocal microscopy induces intracellular calcium transients and cell death. Am J Physiol Cell Physiol2003; 284: C1083–9.
10.
RobertsS.R., KnightM.M., LeeD.A., BaderD.L.Mechanical compression influences intracellular Ca2+ signaling in chondrocytes seeded in agarose constructs. J Appl Physiol2001; 90: 1385–91.
11.
KawanoS., OtsuK., KurumaA.. ATP autocrine/paracrine signaling induces calcium oscillations and NFAT activation in human mesenchymal stem cells. Cell Calcium2006; 39: 313–24.
12.
KawanoS., OtsuK., ShojiS., YamagataK., HiraokaM.Ca(2+) oscillations regulated by Na(+)-Ca(2+) exchanger and plasma membrane Ca(2+) pump induce fluctuations of membrane currents and potentials in human mesenchymal stem cells. Cell Calcium2003; 34: 145–56.
13.
GomezP., VereeckeJ., HimpensB.Intra- and intercellular Ca(2+)-transient propagation in normal and high glucose solutions in ROS cells during mechanical stimulation. Cell Calcium2001; 29: 137–48.
14.
RiddleR.C., TaylorA.F., GenetosD.C., DonahueH.J.MAP kinase and calcium signaling mediate fluid flow-induced human mesenchymal stem cell proliferation. Am J Physiol Cell Physiol2006; 290: C776–84.
15.
XiaoG., GopalakrishnanR., JiangD., ReithE., BensonM.D., FranceschiR.T.Bone morphogenetic proteins, extracellular matrix, and mitogen-activated protein kinase signaling pathways are required for osteoblast-specific gene expression and differentiation in MC3T3-E1 cells. J Bone Miner Res2002; 17: 101–10.
16.
JaiswalR.K., JaiswalN., BruderS.P., MbalavieleG., MarshakD.R., PittengerM.F.Adult human mesenchymal stem cell differentiation to the osteogenic or adipogenic lineage is regulated by mitogen-activated protein kinase. J Biol Chem2000; 275: 9645–52.
17.
KnightM.M., RossJ.M., SherwinA.F., LeeD.A., BaderD.L., PooleC.A.Chondrocyte deformation within mechanically and enzymatically expressed chondrons compressed in agarose. Biochim Biophys Acta2001; 1526: 141–6.
18.
KnightM.M., van de Breevaart BravenboerJ., LeeD.A., van OschG.J., WeimansH., BaderD.L.Cell and nucleus deformation in compressed chondrocyte-alginate constructs: temporal changes and calculation of cell modulus. Biochim Biophys Acta2002; 1570: 1–8.
SolurshM.Cell-cell interactions and chondrogenesis. In HallB.K., ed. Cartilage: development, differentiation and growth.New York: Academic Press, 1983; 121–42.
21.
KawanoS., ShojiS., IchinoseS., YamagataK., TagamiM., HiraokaM.Characterization of Ca(2+) signaling pathways in human mesenchymal stem cells. Cell Calcium2002; 32: 165–74.
22.
ForemanM.A., SmithJ., PublicoverS.J.Characterisation of serum-induced intracellular Ca2+ oscillations in primary bone marrow stromal cells. J Cell Physiol2006; 206: 664–71.
23.
CongetP.A., MingellJ.J.Phenotypical and functional properties of human bone marrow mesenchymal progenitor cells. J Cell Physiol1999; 181: 67–73.
24.
MuragliaA., CanceddaR., QuartoR.Clonal mesenchymal progenitors from human bone marrow differentiate in vitro according to a hierarchical model. J Cell Sci2000; 113: 1161–6.
25.
KamiokaH., SugawaraY., MurshidS.A., IshiharaY., HonjoT., Takano-YamamotoT.Fluid shear stress induces less calcium response in a single primary osteocyte than in a single osteoblast: implication of different focal adhesion formation. J Bone Miner Res2006; 21: 1012–21.
26.
TomaC., PittengerM.F., CahillK.S., ByrneB.J., KesslerP.D.Human mesenchymal stem cells differentiate to a cardiomyocyte phenotype in the adult murine heart. Circulation2002; 105: 93–8.
FickertS., FiedlerJ., BrennerR.E.Identification, quantification and isolation of mesenchymal progenitor cells from osteoarthritic synovium by fluorescence automated cell sorting. Osteoarthritis Cartilage2003; 11: 790–800.
29.
LagarkovaM.A., LyakishevaA.V., FilonenkoE.S.. Characteristics of human bone marrow mesenchymal stem cells isolated by immunomagnetic selection. Bull Exp Biol Med2006; 141: 112–6.
30.
Pingguan-MurphyB., El-AzzehM., BaderD.L., KnightM.M.Cyclic compression of chondrocytes modulates a purinergic calcium signalling pathway in a strain rate-and frequency-dependent manner. J Cell Physiol2006; 209: 389–97.
31.
GuilakF., ZellR.A., EricksonG.R.. Mechanically induced calcium waves in articular chondrocytes are inhibited by gadolinium and amiloride. J Orthop Res1999; 17: 421–9.
32.
YouJ., ReillyG.C., ZhenX.. Osteopontin gene regulation by oscillatory fluid flow via intracellular calcium mobilization and activation of mitogen-activated protein kinase in MC3T3-E1 osteoblasts. J Biol Chem2001; 276: 13365–71.
33.
SalasznykR.M., KleesR.F., WestcottA.M., VandenbergS., BennettK., PlopperG.E.Focusing of gene expression as the basis of stem cell differentiation. Stem Cells Dev2005; 14: 608–20.
