Heat shock protein 90 protects rat mesenchymal stem cells against hypoxia and serum deprivation-induced apoptosis via the PI3K/Akt and ERK1/2 pathways

Abstract

Mesenchymal stem cell (MSC) transplantation has shown a therapeutic potential to repair the ischemic and infracted myocardium, but the effects are limited by the apoptosis and loss of donor cells in host cardiac microenvironment. The aim of this study is to explore the cytoprotection of heat shock protein 90 (Hsp90) against hypoxia and serum deprivation-induced apoptosis and the possible mechanisms in rat MSCs. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis was assessed by Hoechst 33258 nuclear staining and flow cytometric analysis with annexin V/PI staining. The gene expression of Toll-like receptor-4 (TLR-4) and V-erb-b2 erythroblastic leukemia viral oncogene homolog 2 (ErbB2) was detected by real-time polymerase chain reaction (PCR). The protein levels of cleaved caspase-3, Bcl-2, Bcl-xL, Bax, total-ERK, phospho-ERK, total-Akt, phospho-Akt, and Hsp90 were detected by Western blot. The production of nitric oxide was measured by spectrophotometric assay. Hsp90 improves MSC viability and protects MSCs against apoptosis induced by serum deprivation and hypoxia. The protective role of Hsp90 not only elevates Bcl-2/Bax and Bcl-xL/Bax expression and attenuates cleaved caspase-3 expression via down-regulating membrane TLR-4 and ErbB2 receptors and then activating their downstream PI3K/Akt and ERK1/2 pathways, but also enhances the paracrine effect of MSCs. These findings demonstrated a novel and effective treatment strategy against MSC apoptosis in cell transplantation.

Heat Shock Protein 90 Stimulates Rat Mesenchymal Stem Cell Migration via PI3K/Akt and ERK1/2 Pathways

“…Tsutsumi et al [18] reported using a specific Hsp90 inhibitor, DMAG-Noxide, to significantly attenuate tumor cell migration and integrin/extracellular matrix-dependent cytoskeletal reorganization. Our previous study showed that Hsp90 protects rat MSCs against hypoxia and serum deprivation-induced apoptosis via the PI3K/Akt and ERK1/2 pathways [19]. However, whether Hsp90 plays an important role in regulating MSCs migration is still unclear.…”

Protective mechanisms of hypaconitine and glycyrrhetinic acid compatibility in oxygen and glucose deprivation injury

“…Meanwhile, studies have demonstrated that an increased expression of pro-apoptotic Bax family proteins and a decreased expression of anti-apoptotic Bcl-2 family proteins were connected with the process of cell apoptosis (He et al, 2010;Yu et al, 2010). In the whole pathway system, Bax and Bcl-2 are the relevant downstream indexes of PI3K/Akt signaling pathway (Gao et al, 2010) and their regulation can induce the activity of caspase-9, so we evaluated the protein expression of Akt, p-Akt, caspase-9, Bax, and Bcl-2 to elucidate the possible mechanism pathway. Our data showed that HA+GA inhibited the cell apoptosis through suppressing Bax and caspase-9 expression and increasing Bcl-2 synthesis.…”

Interplay between histone acetylation/deacetylation and poly(ADP-ribosyl)ation in the development of ischemic tolerance in vitro

“…According to this hypothesis, HDAC inhibitors, that are able to prevent the reduction of acetylation in models of cerebral ischemia, up-regulate protein levels of Bcl-2, Hsp70, pCREB, BDNF, GFAP, pAKT and reduce the ischemia-induced increase in expression of p53, NOS, COX-2, TNF-a and IL-b; (Faraco et al, 2006;Kim et al, 2007Kim et al, , 2009. In this study, we show that the mild increase in acetylation induced by NMDA preconditioning is associated with a downstream increase in ERK 1/2 phosphorylation, a crucial prosurvival signaling pathway in models of ischemic tolerance (Shamloo et al, 1999;Choi et al, 2006;Gao et al, 2010;Gerace et al, 2012). Similarly, Sinn and colleagues (Sinn et al, 2007) have reported that increased acetylation by the HDAC inhibitor valproate activates the translation of pERK in a model of intracerebral hemorrhage.…”