Hypoxia preconditioning promotes mesenchymal stem cells survival and vascularization through the activation of MALAT1/miR-195/VEGFA axis
Lingyun Wang sun yat sen memorial hospital of sun yat sen university Zhengfei Yang sun yat sen memorial hospital of sun yat sen university Guanghui Zheng sun yat sen memorial hospital of sun yat sen university Tianzhu Guo sun yat sen memorial hospital of sun yat sen university Menglei Yu sun yat sen memorial hospital of sun yat sen university Abstract Background: Previous studies have demonstrated that hypoxia preconditioning (HP) can promote mesenchymal stem cells (MSCs) survival and
... vival and vascularization. Long noncoding RNA metastasisassociated lung adenocarcinoma transcript 1 (MALAT1) is a newly discovered regulator of MSCs viability and differentiation. Evidences have indicated that MALAT1 can be strongly induced by hypoxia. This study aimed to investigate the role of MALAT1 in HP mediated MSCs survival and vascularization as well as the relevant underlying mechanism in vitro. Methods: MSCs were obtained from C57BL/6 mice and cultured in vitro. Cells at the third passage were divided into the following groups: normoxia (N), hypoxia preconditioning (HP), HP + MALAT1, HP + MALAT1 NC, HP+si-MALAT1 and HP +si-MALAT1 NC. The normoxia group was cultured in 20% O2 for 24 h. All the other groups were exposed to hypoxia (1% O2) for 24 hours. MALAT1 and relevant scramble RNA were transfected in the HP+MALAT1 and HP+MALAT1 NC groups respectively. HP+si-MALAT1 and HP +si-MALAT1 NC groups were transfected with MALAT1 siRNA and relevant siRNA scramble respectively. MSCs proliferation, apoptosis and vascular densities were evaluated. Bioinformatics and dual luciferase reporter assay were performed. Relevant biomarkers were examined in different experimental groups. Results: MSCs survival and vascularization were significantly enhanced in the HP group. Transfection of MALAT1 further strengthened the viability and angiogenic potential of MSCs in the condition of HP, whereas its knockdown attenuated cells survival and vascularization. MALAT1 and vascular endothelial growth factor A (VEGFA) were obviously increased after hypoxia exposure, while miR-195 was decreased. miR-195 targeted and downregulated VEGFA. miR-195 was a target of MALAT1. Overexpression of MALAT1 led to a decreased level of miR-195, accompanied with an augmented expression of VEGFA. However, both miR-195 and VEGFA exhibited contrary alterations after MALAT1 blockage. Conclusion: HP enhanced MSCs survival and vascularization potential in vitro, and the activation of MALAT1/miR-195/VEGFA axis might be involved in this procedure. This study reveals a new molecular mechanism of HP mediated MSCs survival and vascularization. It will be conducive for the 3 development of novel strategies to improve the therapeutic efficiency of MSCs based on HP.