Clusterin/Akt up-regulation is critical for GATA-4 mediated cytoprotection of mesenchymal stem cells against ischemia injury

Bin Yu, Yueting Yang, Huan Liu, Min Gong, Ronald W. Millard, Yi Gang Wang, Muhammad Ashraf, Meifeng Xu

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3 Scopus citations

Abstract

Background: Clusterin (Clu) is a stress-responding protein with multiple biological functions. Our preliminary microarray studies show that clusterin was prominently upregulated in mesenchymal stem cells (MSCs) overexpressing GATA-4 (MSCGATA-4). We hypothesized that the upregulation of clusterin is involved in overexpression of GATA-4 mediated cytoprotection. Methods: MSCs harvested from bone marrow of rats were transduced with GATA-4. The expression of clusterin in MSCs was further confirmed by real-time PCR and western blotting. Simulation of ischemia was achieved by exposure of MSCs to a hypoxic environment. Lactate dehydrogenase (LDH) released from MSCs was served as a biomarkerof cell injury and MTs uptake was used to estimate cell viability. Mitochondrial function was evaluated by measuring mitochondrial membrane potential (Δm) and caspase 3/7 activity. Results: (1) Clusterin expression was up-regulated in MSCGATA-4 compared to control MSCs transfected with empty-vector (MSCNull). MSCGATA-4 were tolerant to 72 h hypoxia exposure as shown by reduced LDH release and higher MTs uptake. This protection was abrogated by transfecting Clu-siRNA into MSCGATA-4. (2) Exogenous clusterin significantly decreased LDH release and increased MSC survival in hypoxic environment. Moreover, AMμm was maintained and caspase 3/7 activity was reduced by clusterin in a concentration-dependent manner. (3) p-Akt expression in MSCs was upregulated following pre-treatment with clusterin, with no change in total Akt. Moreover, cytoprotection mediated by clusterin was partially abrogated by Akt inhibitor LY294002. Conclusions: Clusterin/Akt signaling pathway is involved in GATA-4 mediated cytoprotection against hypoxia stress. It is suggested that clusterin may be therapeutically exploited in MSC based therapy for cardiovascular diseases.

Original languageEnglish (US)
Article numbere0151542
JournalPloS one
Volume11
Issue number3
DOIs
StatePublished - Mar 2016
Externally publishedYes

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ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • General

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