37
views
0
recommends
+1 Recommend
1 collections
    0
    shares

      Call for Papers: Green Renal Replacement Therapy: Caring for the Environment

      Submit here before July 31, 2024

      About Blood Purification: 3.0 Impact Factor I 5.6 CiteScore I 0.83 Scimago Journal & Country Rank (SJR)

      • Record: found
      • Abstract: found
      • Article: found

      Glycyrrhizic acid ameliorates HMGB1-mediated cell death and inflammation after renal ischemia reperfusion injury.

      Read this article at

      ScienceOpenPublisherPubMed
          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

          Renal ischemia reperfusion injury (IRI) leads to acute kidney injury (AKI) and the death of tubular epithelial cells (TEC). The release of high-mobility group box-1 (HMGB1) and other damage-associated molecular pattern moieties from dying cells may promote organ dysfunction and inflammation by effects on TEC. Glycyrrhizic acid (GZA) is a functional inhibitor of HMGB1, but its ability to attenuate the HMGB1-mediated injury of TEC has not been tested.

          Related collections

          Most cited references29

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

          HMGB1 signals through toll-like receptor (TLR) 4 and TLR2.

          In response to bacterial endotoxin (e.g., LPS) or endogenous proinflammatory cytokines (e.g., TNF and IL-1beta), innate immune cells release HMGB1, a late cytokine mediator of lethal endotoxemia and sepsis. The delayed kinetics of HMGB1 release makes it an attractive therapeutic target with a wider window of opportunity for the treatment of lethal systemic inflammation. However, the receptor(s) responsible for HMGB1-mediated production of proinflammatory cytokines has not been well characterized. Here we demonstrate that in human whole blood, neutralizing antibodies against Toll-like receptor 4 (TLR4, but not TLR2 or receptor for advanced glycation end product) dose-dependently attenuate HMGB1-induced IL-8 release. Similarly, in primary human macrophages, HMGB1-induced TNF release is dose-dependently inhibited by anti-TLR4 antibodies. In primary macrophages from knockout mice, HMGB1 activates significantly less TNF release in cells obtained from MyD88 and TLR4 knockout mice as compared with cells from TLR2 knockout and wild-type controls. However, in human embryonic kidney 293 cells transfected with TLR2 or TLR4, HMGB1 effectively induces IL-8 release only from TLR2 overexpressing cells. Consistently, anti-TLR2 antibodies dose-dependently attenuate HMGB1-induced IL-8 release in human embryonic kidney/TLR2-expressing cells and markedly reduce HMGB1 cell surface binding on murine macrophage-like RAW 264.7 cells. Taken together, our data suggest that there is a differential usage of TLR2 and TLR4 in HMGB1 signaling in primary cells and in established cell lines, adding complexity to studies of HMGB1 signaling which was not previously expected.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            The nuclear protein HMGB1 is secreted by monocytes via a non-classical, vesicle-mediated secretory pathway.

            HMGB1, a non-histone nuclear factor, acts extracellularly as a mediator of delayed endotoxin lethality, which raises the question of how a nuclear protein can reach the extracellular space. We show that activation of monocytes results in the redistribution of HMGB1 from the nucleus to cytoplasmic organelles, which display ultrastructural features of endolysosomes. HMGB1 secretion is induced by stimuli triggering lysosome exocytosis. The early mediator of inflammation interleukin (IL)-1beta is also secreted by monocytes through a non-classical pathway involving exocytosis of secretory lysosomes. However, in keeping with their respective role of early and late inflammatory factors, IL-1beta and HMGB1 respond at different times to different stimuli: IL-1beta secretion is induced earlier by ATP, autocrinally released by monocytes soon after activation; HMGB1 secretion is triggered by lysophosphatidylcholine, generated later in the inflammation site. Thus, in monocytes, non-classical secretion can occur through vescicle compartments that are at least partially distinct.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              TLR4 activation mediates kidney ischemia/reperfusion injury.

              Ischemia/reperfusion injury (IRI) may activate innate immunity through the engagement of TLRs by endogenous ligands. TLR4 expressed within the kidney is a potential mediator of innate activation and inflammation. Using a mouse model of kidney IRI, we demonstrated a significant increase in TLR4 expression by tubular epithelial cells (TECs) and infiltrating leukocytes within the kidney following ischemia. TLR4 signaling through the MyD88-dependent pathway was required for the full development of kidney IRI, as both TLR4(-/-) and MyD88(-/-) mice were protected against kidney dysfunction, tubular damage, neutrophil and macrophage accumulation, and expression of proinflammatory cytokines and chemokines. In vitro, WT kidney TECs produced proinflammatory cytokines and chemokines and underwent apoptosis after ischemia. These effects were attenuated in TLR4(-/-) and MyD88(-/-) TECs. In addition, we demonstrated upregulation of the endogenous ligands high-mobility group box 1 (HMGB1), hyaluronan, and biglycan, providing circumstantial evidence that one or more of these ligands may be the source of TLR4 activation. To determine the relative contribution of TLR4 expression by parenchymal cells or leukocytes to kidney damage during IRI, we generated chimeric mice. TLR4(-/-) mice engrafted with WT hematopoietic cells had significantly lower serum creatinine and less tubular damage than WT mice reconstituted with TLR4(-/-) BM, suggesting that TLR4 signaling in intrinsic kidney cells plays the dominant role in mediating kidney damage.
                Bookmark

                Author and article information

                Journal
                Am. J. Nephrol.
                American journal of nephrology
                1421-9670
                0250-8095
                2014
                : 40
                : 1
                Affiliations
                [1 ] Matthew Mailing Centre for Translational Transplant Studies, London Health Sciences Centre, London, Ont., Canada.
                Article
                000364908
                10.1159/000364908
                25059568
                2959fe45-b59f-4555-8e5d-a7f7dcf1f7af
                © 2014 S. Karger AG, Basel.
                History

                Comments

                Comment on this article