15
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Ischemic preconditioning attenuates ischemia/reperfusion-induced kidney injury by activating autophagy via the SGK1 signaling pathway

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Ischemic preconditioning (IPC) has a strong renoprotective effect during renal ischemia/reperfusion (I/R) injury that is thought to relate to autophagy. However, the role of autophagy during IPC-afforded renoprotection and the precise mechanisms involved are unknown. In this study, an in vitro hypoxia/reoxygenation (H/R) model was established in which oxygen and glucose deprivation (OGD) was applied to renal cells for 15 h followed by reoxygenation under normal conditions for 30 min, 2 h or 6 h; transient OGD and subsequent reoxygenation were implemented before prolonged H/R injury to achieve hypoxic preconditioning (HPC). 3-Methyladenine (3-MA) was used to inhibit autophagy. In a renal I/R injury model, rats were subjected to 40 min of renal ischemia followed by 6 h, 12 h or 24 h of reperfusion. IPC was produced by four cycles of ischemia (8 min each) followed by 5 min of reperfusion prior to sustained ischemia. We found that IPC increased LC3II and Beclin-1 levels and decreased SQSTM/p62 and cleaved caspase-3 levels in a time-dependent manner during renal I/R injury, as well as increased the number of intracellular double-membrane vesicles in injured renal cells. IPC-induced renal protection was efficiently attenuated by pretreatment with 5 mM 3-MA. Pretreatment with IPC also dynamically affected the expression of SGK1/FOXO3a/HIF-1α signaling components. Moreover, knocking down SGK1 expression significantly downregulated phosphorylated-FOXO3a (p-FOXO3a)/FOXO3 and HIF-1α, suppressed LC3II and Beclin-1 levels, increased SQSTM/p62 and cleaved caspase-3 levels, and abolished the protective effect of IPC against I/R-induced renal damage. SGK1 overexpression efficiently increased p-FOXO3a/FOXO3 and HIF-1α levels, promoted the autophagy flux and enhanced the protective effect mediated by HPC. Furthermore, FOXO3a overexpression decreased HIF-1α protein levels, inhibited HIF-1α transcriptional activity and reduced the protective effect of IPC. Our study indicates that IPC can ameliorate renal I/R injury by promoting autophagy through the SGK1 pathway.

          Related collections

          Most cited references39

          • Record: found
          • Abstract: found
          • Article: not found

          Mitochondrial autophagy is an HIF-1-dependent adaptive metabolic response to hypoxia.

          Autophagy is a process by which cytoplasmic organelles can be catabolized either to remove defective structures or as a means of providing macromolecules for energy generation under conditions of nutrient starvation. In this study we demonstrate that mitochondrial autophagy is induced by hypoxia, that this process requires the hypoxia-dependent factor-1-dependent expression of BNIP3 and the constitutive expression of Beclin-1 and Atg5, and that in cells subjected to prolonged hypoxia, mitochondrial autophagy is an adaptive metabolic response which is necessary to prevent increased levels of reactive oxygen species and cell death.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            FOXOs, cancer and regulation of apoptosis.

            Forkhead box O (FOXO) transcription factors are involved in multiple signaling pathways and play critical roles in a number of physiological and pathological processes including cancer. The importance of FOXO factors ascribes them under multiple levels of regulation including phosphorylation, acetylation/deacetylation, ubiquitination and protein-protein interactions. As FOXO factors play a pivotal role in cell fate decision, mounting evidence suggests that FOXO factors function as tumor suppressors in a variety of cancers. FOXOs are actively involved in promoting apoptosis in a mitochondria-independent and -dependent manner by inducing the expression of death receptor ligands, including Fas ligand and tumor necrosis factor-related apoptosis-inducing ligand, and Bcl-2 family members, such as Bim, bNIP3 and Bcl-X(L), respectively. An understanding of FOXO proteins and their biology will provide new opportunities for developing more effective therapeutic approaches to treat cancer.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Life with oxygen.

              The survival of all metazoan organisms is dependent on the regulation of O2 delivery and utilization to maintain a balance between the generation of energy and production of potentially toxic oxidants. Hypoxia-inducible factor 1 (HIF-1) is a transcription factor that functions as a master regulator of oxygen homeostasis and has essential roles in metazoan development, physiology, and disease pathogenesis. Remarkable progress has been made in delineating the molecular mechanisms whereby changes in cellular oxygenation are transduced to the nucleus as changes in gene transcription through the activity of HIF-1. Pharmacologic agents that activate or inhibit the hypoxia signal transduction pathway may be useful therapies for ischemic and neoplastic disorders, respectively, which are the major causes of mortality in industrialized societies.
                Bookmark

                Author and article information

                Contributors
                +86 15901907506 , drzhxl@163.com
                Journal
                Cell Death Dis
                Cell Death Dis
                Cell Death & Disease
                Nature Publishing Group UK (London )
                2041-4889
                1 March 2018
                1 March 2018
                March 2018
                : 9
                : 3
                : 338
                Affiliations
                [1 ]ISNI 0000 0001 0125 2443, GRID grid.8547.e, Department of Nephrology, Huadong Hospital, , Fudan University, ; Shanghai, China
                [2 ]Shanghai Key Laboratory of Clinical Geriatric Medicine, Shanghai, China
                Author information
                http://orcid.org/0000-0003-2461-419X
                Article
                358
                10.1038/s41419-018-0358-7
                5832808
                29497029
                2eb9f46b-5bef-4521-bceb-373da8e7ec52
                © The Author(s) 2018

                Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

                History
                : 8 August 2017
                : 22 January 2018
                : 23 January 2018
                Categories
                Article
                Custom metadata
                © The Author(s) 2018

                Cell biology
                Cell biology

                Comments

                Comment on this article