Large tumor suppressor gene 2-mediated Hippo signaling pathway regulates the biological behavior of mesenchymal stem cells in vitro

Abstract

To investigate the regulatory effect of Hippo signaling pathway mediated by large tumor suppressor gene 2 (LATS2) on biological behavior of mice bone marrow mesenchymal stem cells (BMSCs) in vitro. BMSCs of C57BL/6 mice were cultured in vitro and passed to the 6th to 7th generations for experiment. BMSCs with activated and inactivated LATS2 were constructed with lentiviral vectors transfections. The BMSCs were allocated to blank control group (MSC group), empty vector control group (MSC-eGFP group), LATS2-overexpressing group (MSC-LATS2 group), empty vector without LATS2 shRNA control group (MSC-shcontrol group) and LATS2-underexpressing group (MSC-shLATS2 group). The transduction efficiencies mediated by the lentiviral vectors were evaluated by flow cytometry. The mRNA and protein expressions of LATS2, phosphorylation of Yes associated protein (p-YAP) and 14-3-3 were quantified by reverse transcription-polymerase chain reaction (RT-PCR) and Western Blot respectively. Osteogenic and adipogenic differentiation of BMSCs were evaluated through alizarin red and oil red O staining. Proliferation of BMSCs was evaluated using the CCK-8 assay. The effect of Hippo pathway on horizontal and vertical migration ability of BMSCs was measured by the scratch test and Transwell chamber test. The transduction efficiencies mediated by the lentiviral vectors were 93.1%-97.1%. Compared with MSC-eGFP group, the expressions of LATS2, p-YAP and 14-3-3 in MSC-LATS2 group were significantly elevated [LATS2 mRNA (2-ΔΔCT): 2.55±0.13 vs. 1.08±0.05, LATS2/GAPDH: 2.63±0.11 vs. 1.06±0.08, p-YAP/total YAP: 1.67±0.11 vs. 1.00±0.04, 14-3-3/β-actin: 2.22±0.20 vs. 0.98±0.06, all P < 0.05], however, compared with MSC-shcontrol group, the expressions in MSC-shLATS2 group were significantly reduced [LATS2 mRNA (2-ΔΔCT): 0.10±0.01 vs. 1.01±0.05, LATS2/GAPDH: 0.09±0.01 vs. 1.05±0.06, p-YAP/total YAP: 0.10±0.02 vs. 1.10±0.09, 14-3-3/β-actin: 0.05±0.01 vs. 0.90±0.08, all P < 0.05]. It suggested that high and low expression of LATS2 could activate or inhibit Hippo pathway. The osteogenic and adipogenic differentiation and proliferation rate of BMSCs in MSC-LATS2 group were significantly lower than those in MSC-eGFP group, however, those in MSC-shLATS2 group were significantly higher than MSC-shontrol group (all P < 0.05). It suggested that high and low expression of LATS2 could inhibit or promote osteogenesis, adipogenesis and cell proliferation of BMSCs. Scratch test and Transwell chamber test showed that the degree of scratch healing in MSC-LATS2 group was significantly lower than that in MSC-eGFP group [(22.11±3.02)% vs. (45.99±6.58)%], while the number of cells migrating to the subventricular layer of Transwell was significantly reduced (cells/MP: 20.82±3.05 vs. 111.33±13.28, both P < 0.05); the degree of scratch healing in MSC-shLATS2 group was significantly higher than that in MSC-shcontrol group [(70.32±7.17)% vs. (39.28±2.98)%], the number of cells migrating to the subventricular layer of Transwell was increased significantly (cells/MP: 206.19±30.58 vs. 120.10±25.10, both P < 0.05). It suggested that high and low expression of LATS2 could inhibit or promote the horizontal and vertical migration of BMSCs. LATS2-mediated alteration of Hippo pathway could modulate differentiation, proliferation, and migration of mesenchymal stem cells in vitro.