Effects of Hippo pathway on differentiation, proliferation, migration of bone marrow mesenchymal stem cells in vitro

Abstract

To explore the effects of Hippo pathway on differentiation, proliferation, and migration of bone marrow mesenchymal stem cells (BMSCs) in vitro. BMSCs of C57BL/6 mice were identified using fluorescence-activated cellsorting analysis and the capabilities of osteogenic, chondrogenic and adipogenic differentiation were evaluated. The differentiation of BMSCs to type II alveolar epithelial cells (AEC II) was induced by indirect co-culture with mouse lung epithelial cells (MLE-12) and small airway epithelial cell growth medium (SAGM). The Hippo pathway was regulated by 2-deoxy-D-glucose (2-DG) and 9E1, the effects of 2-DG and 9E1 on the expression of BMSCs surface proteins (SPB, SPC and SPD) mRNA and pro-SPC protein were detected by real time quantitative polymerase chain reaction (qRT-PCR) and Western Blot. The effect of Hippo pathway on differentiation of BMSCs to AEC II cells was evaluated. The effect of Hippo pathway on the proliferation of BMSCs was evaluated by methyl thiazolyl tetrazolium (MTT) assay (intervention of 0.1, 0.5, 1.0, 5.0 mmol/L 2-DG). The scratch test and Transwell chamber test were used to analyze the effect of Hippo pathway on migration ability of BMSCs to conditioned medium of acute respiratory distress syndrome (ARDS) lung tissue. 2-DG could activate Hippo pathway in a dose-dependent manner and promote the differentiation to AEC II and proliferation of BMSCs, the maximum effects were observed after 5 mmol/L of 2-DG treatment [SPB mRNA (2-ΔΔCT): 2.42±0.28 vs. 1.89±0.11, SPC mRNA (2-ΔΔCT): 8.06±0.68 vs. 6.59±0.79, SPD mRNA (2-ΔΔCT): 6.45±0.37 vs. 5.27±0.28, pro-SPC/β-actin: 5.80±1.86 vs. 4.93±1.18, proliferation rate: (145.46±18.18)% vs. (98.91±4.36)%, all P < 0.05], but 9E1 could reverse those effects through inhibition of Hippo pathway [SPB mRNA (2-ΔΔCT): 1.32±0.17 vs. 1.89±0.11, SPC mRNA (2-ΔΔCT): 3.91±0.34 vs. 6.59±0.79, SPD mRNA (2-ΔΔCT): 3.38±0.25 vs. 5.27±0.28, pro-SPC/β-actin: 2.48±0.17 vs. 4.93±1.18, proliferation rate: (80.00±7.27)% vs. (98.91±4.36)%, all P < 0.05]. The ability of horizontal migration [wound healing: (27.17±3.53)% vs. (52.45±6.52)%, P < 0.05] and homing BMSCs to conditioned medium of ARDS lung tissue [cell count (fold, relative to control): 2.77±0.21 vs. 1.90±0.19, P < 0.05] were increased after activation of Hippo pathway by 2-DG treatment, but those effects were reversed after inhibition of Hippo pathway by 9E1 treatment [wound healing: (79.89±8.42)% vs. (52.45±6.52)%, cell count (fold, relative to control): 1.69±0.13 vs. 1.90±0.19, both P < 0.05]. Activation of Hippo pathway could enhance differentiation of BMSCs to AEC II, promote proliferation and ability of horizontal migration and homing BMSCs to conditioned medium of ARDS lung tissue in vitro.