Quiescent Human Mesenchymal Stem Cells Are More Resistant to Heat Stress than Cycling Cells

Hindawi Stem Cells International Volume 2018, Article ID 3753547, 15 pages https://doi.org/10.1155/2018/3753547 Research Article Quiescent Human Mesenchymal Stem Cells Are More Resistant to Heat Stress than Cycling Cells L. L. Alekseenko ,1 M. A. Shilina ,1 O. G. Lyublinskaya ,1 J. S. Kornienko ,2 O. V. Anatskaya ,1 A. E. Vinogradov ,1 T. M. Grinchuk ,1 I. I. Fridlyanskaya ,1 and N. N. Nikolsky1 1 2 Institute of Cytology, Russian Academy of Sciences, Saint Petersburg, Russia Peter the Great St. Petersburg Polytechnic University, Saint Petersburg, Russia Correspondence should be addressed to L. L. Alekseenko; , M. A. Shilina; , and O. G. Lyublinskaya; Received 23 May 2018; Revised 20 August 2018; Accepted 26 September 2018; Published 24 December 2018 Guest Editor: Hyun Nam Copyright © 2018 L. L. Alekseenko et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Quiescence is the prevailing state of many cell types under homeostatic conditions. Yet, surprisingly, little is known about how quiescent cells respond to environmental challenges. The aim of the present study is to compare stress responses of cycling and quiescent mesenchymal stem cells (MSC). Human endometrial mesenchymal cells (eMSС) were employed as adult stem cells. eMSC quiescence was modeled by serum starvation. Sublethal heat shock (HS) was used as a stress factor. Both quiescent and cycling cells were heated at 45°C for 30 min and then returned to standard culture conditions for their recovery. HS response was monitored by DNA damage response, stress-induced premature senescence (SIPS), cell proliferation activity, and oxidative metabolism. It has been found that quiescent cells repair DNA more rapidly, resume proliferation, and undergo SIPS less than proliferating cells. HS-enforced ROS production in heated cycling cells was accompanied with increased expression of genes regulating redox-active proteins. Quiescent cells exposed to HS did not intensify the ROS production, and genes involved in antioxidant defense were mostly silent. Altogether, the results have shown that quiescent cells are more resistant to heat stress than cycling cells. Next-generation sequencing (NGS) demonstrates that HS-survived cells retain differentiation capacity and do not exhibit signs of spontaneous transformation. 1. Introduction Human MSC as promising cell therapy candidates are under intensive investigation. Their differentiation abilities, immunomodulatory effects, and homing properties offer potential for augmenting regenerative capacity of many tissues. Mesenchymal stem cells are fibroblast-like adherent cells, which can be isolated from various tissues, such as bone marrow, umbilical cord, adipose tissue, peripheral blood, spleen, and skin [1]. Currently, MSC derived from endometrium (eMSC) attract growing attention. Comparing with other MSC types, eMSC show a higher vasculogenic, anti-inflammatory, and immunomodulation potential [2, 3]. These valuable features are associated with a special role of eMSC in endometrial regrowth every month. Cultured eMSC are applied in clinical trials and encouraging results have been reported [4, 5]. A major impediment to the development of MSC-based therapies, however, is poor cell survival at the site of injury. Generally, the harsh environment of injured tissue is associated with oxidative stress, chronic inflammation, fibrosis, extracellular matrix degradation, and immune rejection [6]. This is why the stress response of cultivated human stem cells is under intensive study [7–11]. Cells exposed to stress may respond differently: undergo differentiation, senescence (SIPS), apoptosis, or necrosis. The choice depends on the cell type and stress strength. Mild stress may improve differentiation of stem cells [12, 13]. The outcome for unbearable stress is necrosis. Sublethal doses of various stressors mostly produce senescence (SIPS) and sometimes later apoptosis. Heat stress (heat shock, hyperthermia) is one of the wellstudied types of stress. It can affect a variety of cell types. 2 Hyperthermia can accompany therapeutic procedures, such as stem cell-based therapy and cancer treatment. Hyperthermia changes the blood circulation and oxygen supply reduces the ATP level and increases anaerobic metabolites and activity of DNA repair proteins. It has various effects on the immune system, such as increased peripheral blood mononuclear cell proliferation, increased cytotoxic activity of CD8+ T cells and augmented secretion of IFN-γ by these cells. It also causes the secretion of inflammatory cytokines, such as TNF-α and IL-1, alters the migration of Langerhans cells, and provokes lymphocyte homing into secondary lymphoid tissues. Heat-shocked MSC can inhibit tumor growth and enhance tumor cell death [14]. Hyperthermia was applied in vivo to stimulate osteogenesis [15, 16]. It was demonstrated that mild heat stress promoted myoblast differentiation [17] and osteogenesis of bone marrow MSC [18, 19]. Severe HS common for orthopedic procedures induced apoptosis and necrosis in cultured osteoblasts [20, 21]. Proliferation of dental follicle stem cells was stimulated by increased temperature [22, 23]. Enlarged temperature enhanced the proliferation of UCV-MSC cocultured with mononuclear cells of the peripheral blood as well as expression of IL-10, TGF-β1, and FOXP3 mRNAs. It had no effect on IL-17A and IFN-γ secretion and reduced CXCL12 [24]. In our experiments, sublethal temperature has induced preliminary senescence [25] which is a mechanism of maintenance of MSC genetic stability by excluding damaged cells from the proliferation pool. In a living body, stem cells may long reside in the dormant state entering the cell cycle in response to local signals of damage and other regeneration needs. Quiescence is the prevailing state of many cell types under homeostatic conditions. Proliferating cells in culture can be induced into quiescence by mitogen withdrawal under serum deprivation [26]. Serum deprivation (SD) for 48 hours shifted MSC into a quiescent state in which cells remained metabolically healthy but nonproliferative with reduced levels of RNA and protein synthesis. Upon reintroduction to standard culture conditions, SD-MSC restored proliferation and properties of parental cells. Quiescence preconditioning-afforded MSC increased viability under low oxygen or total glucose depletion [27]. Yet, surprisingly, little is known about how quiescent cells respond to environmental challenges. In this connection, the aim of the present study is to compare heat stress (HS) responses of cycling and quiescent eMSC. Moreover, we examined HS-survived and HS-expanded cells for their differentiation potency and tumorigenic risk using nextgeneration sequencing (NGS). 2. Methods 2.1. Cells. We used MSC isolated from desquamated endometrium of menstrual (...truncated)