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Wang J, Xin lv, Aniwan A, Liu H, Lin Y, Shao X, Zhou S, Yu P. O-GlcNAcylation regulates HIF-1α and induces mesothelial-mesenchymal transition and fibrosis of human peritoneal mesothelial cells. Heliyon 2023; 9:e22916. [PMID: 38144265 PMCID: PMC10746441 DOI: 10.1016/j.heliyon.2023.e22916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 11/22/2023] [Accepted: 11/22/2023] [Indexed: 12/26/2023] Open
Abstract
O-GlcNAcylation is a post-translational modification of proteins that regulates various biological processes. However, its involvement in peritoneal dialysis fibrosis remains unclear. This study aimed to investigate the impact of O-GlcNAcylation on human peritoneal mesothelial cells (HPMCs) cultured in control and high-glucose medium. To manipulate cellular conditions, we employed knockdown techniques targeting HIF-1α and OGT, along with the administration of pharmacological agents (PUGNAc, OSMI-1, MG-132, FG-4592, and HIF-1α inhibitor). Our findings revealed that elevated glucose levels increased global O-GlcNAcylation and the abundance of HIF-1α, α-SMA, fibronectin, and COL1A2. Conversely, the expression of E-Cadherin was decreased. Significantly, a positive correlation was observed between O-GlcNAcylation, HIF-1α, mesothelial-to-mesenchymal transition (MMT), and fibrosis in HPMCs. Notably, O-GlcNAcylation was found to regulate HIF-1α, thereby promoting MMT and fibrosis under high glucose conditions. Furthermore, we discovered that high glucose levels induced O-GlcNAcylation of HIF-1α, preventing its ubiquitination and proteasomal degradation. In summary, our study demonstrates the critical role of O-GlcNAcylation-mediated regulation of HIF-1α in MMT and fibrosis during peritoneal dialysis.
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Affiliation(s)
- Jian Wang
- Department of Nephrology, First Affiliated Hospital of Gannan Medical University, Ganzhou, 341000, China
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, China
| | - Xin lv
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, China
- Department of Nephrology, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, Taiyuan, 030032, China
| | - Ashanjiang Aniwan
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, China
| | - Hongyan Liu
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, China
| | - Yao Lin
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, China
| | - Xian Shao
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, China
| | - Saijun Zhou
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, China
| | - Pei Yu
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, China
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MUW researcher of the month. Wien Klin Wochenschr 2022; 134:892-893. [PMID: 36512129 DOI: 10.1007/s00508-022-02143-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Proteome-Wide Differential Effects of Peritoneal Dialysis Fluid Properties in an In Vitro Human Endothelial Cell Model. Int J Mol Sci 2022; 23:ijms23148010. [PMID: 35887356 PMCID: PMC9317527 DOI: 10.3390/ijms23148010] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/13/2022] [Accepted: 07/15/2022] [Indexed: 01/27/2023] Open
Abstract
To replace kidney function, peritoneal dialysis (PD) utilizes hyperosmotic PD fluids with specific physico-chemical properties. Their composition induces progressive damage of the peritoneum, leading to vasculopathies, decline of membrane function, and PD technique failure. Clinically used PD fluids differ in their composition but still remain bioincompatible. We mapped the molecular pathomechanisms in human endothelial cells induced by the different characteristics of widely used PD fluids by proteomics. Of 7894 identified proteins, 3871 were regulated at least by 1 and 49 by all tested PD fluids. The latter subset was enriched for cell junction-associated proteins. The different PD fluids individually perturbed proteins commonly related to cell stress, survival, and immune function pathways. Modeling two major bioincompatibility factors of PD fluids, acidosis, and glucose degradation products (GDPs) revealed distinct effects on endothelial cell function and regulation of cellular stress responses. Proteins and pathways most strongly affected were members of the oxidative stress response. Addition of the antioxidant and cytoprotective additive, alanyl-glutamine (AlaGln), to PD fluids led to upregulation of thioredoxin reductase-1, an antioxidant protein, potentially explaining the cytoprotective effect of AlaGln. In conclusion, we mapped out the molecular response of endothelial cells to PD fluids, and provided new evidence for their specific pathomechanisms, crucial for improvement of PD therapies.
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Nikolaou MA, Drosos Y, Havaki S, Arvanitis D, Sotiriou S, Vassiou K, Zibis A, Arvanitis LD. The O-Linked N-Acetylglucosamine Containing Epitope H (O-GlcNAcH) is Upregulated in the Trophoblastic and Downregulated in the Fibroblastic Cells in Missed Miscarriage Human Chorionic Villi With Simple Hydropic Degeneration. Int J Gynecol Pathol 2021; 40:324-332. [PMID: 32897971 DOI: 10.1097/pgp.0000000000000693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Epitope H contains an O-linked N-acetylglucosamine (O-GlcNAcH) residue in a specific conformation and/or environment recognized by the mouse monoclonal antibody H. O-GlcNAcH is present in several types of cells and in several polypeptides, including cytokeratin 8 and vimentin, on the latter in cells under stress. In the present work, we examined the expression of the O-GlcNAcH in 60 cases of endometrial curettings from missed miscarriage cases containing normal and simple hydropic degenerated chorionic villi in each case, using monoclonal antibody H and indirect immunoperoxidase and Western blot immunoblot. In all cases examined the expression of the O-GlcNAcH was cytoplasmic as follows: (1) syncytiotrophoblastic cells showed very low expression in chorionic villi (CV) with nonhydropic degeneration (NHD) and high expression in hydropic degenerated (HD) CV; (2) cytotrophoblastic cells showed low expression in CV with NHD and high expression in HD CV; (3) fibroblastic cells showed high expression in CV with NHD and very low expression in HD CV; (4) histiocytes showed very low expression in both types of CV; (5) endothelial cells showed high expression in both types of CV. An immunoblot of CV from one case of a legal abortion from a normal first-trimester pregnancy showed 5 polypeptides with 118.5, 106.3, 85, 53, and 36.7 kD bearing the epitope H and the 53 kD corresponded to cytokeratin 8. The expression of the O-GlcNAcH is upregulated in the trophoblastic cells and downregulated in the fibroblastic cells in the HD CV in comparison to the NHD CV.
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Martinez M, Renuse S, Kreimer S, O'Meally R, Natov P, Madugundu AK, Nirujogi RS, Tahir R, Cole R, Pandey A, Zachara NE. Quantitative Proteomics Reveals that the OGT Interactome Is Remodeled in Response to Oxidative Stress. Mol Cell Proteomics 2021; 20:100069. [PMID: 33716169 PMCID: PMC8079276 DOI: 10.1016/j.mcpro.2021.100069] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 01/26/2021] [Accepted: 03/04/2021] [Indexed: 12/17/2022] Open
Abstract
The dynamic modification of specific serine and threonine residues of intracellular proteins by O-linked N-acetyl-β-D-glucosamine (O-GlcNAc) mitigates injury and promotes cytoprotection in a variety of stress models. The O-GlcNAc transferase (OGT) and the O-GlcNAcase are the sole enzymes that add and remove O-GlcNAc, respectively, from thousands of substrates. It remains unclear how just two enzymes can be specifically controlled to affect glycosylation of target proteins and signaling pathways both basally and in response to stress. Several lines of evidence suggest that protein interactors regulate these responses by affecting OGT and O-GlcNAcase activity, localization, and substrate specificity. To provide insight into the mechanisms by which OGT function is controlled, we have used quantitative proteomics to define OGT's basal and stress-induced interactomes. OGT and its interaction partners were immunoprecipitated from OGT WT, null, and hydrogen peroxide-treated cell lysates that had been isotopically labeled with light, medium, and heavy lysine and arginine (stable isotopic labeling of amino acids in cell culture). In total, more than 130 proteins were found to interact with OGT, many of which change their association upon hydrogen peroxide stress. These proteins include the major OGT cleavage and glycosylation substrate, host cell factor 1, which demonstrated a time-dependent dissociation after stress. To validate less well-characterized interactors, such as glyceraldehyde 3-phosphate dehydrogenase and histone deacetylase 1, we turned to parallel reaction monitoring, which recapitulated our discovery-based stable isotopic labeling of amino acids in cell culture approach. Although the majority of proteins identified are novel OGT interactors, 64% of them are previously characterized glycosylation targets that contain varied domain architecture and function. Together these data demonstrate that OGT interacts with unique and specific interactors in a stress-responsive manner.
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Affiliation(s)
- Marissa Martinez
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States; Currently at Foghorn Therapeutics, Cambridge, Massachusetts, United States
| | - Santosh Renuse
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States; McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States; Currently at the Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, United States; Currently at the Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Simion Kreimer
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States; The Mass Spectrometry and Proteomics Facility, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; Currently at the Advanced Clinical Biosystems Institute, Smidt Heart institute, Cedars Sinai Medical Center, Los Angeles, California, USA
| | - Robert O'Meally
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States; The Mass Spectrometry and Proteomics Facility, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Peter Natov
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States; Currently at the Department of Internal Medicine, Yale New Haven Hospital, Yale School of Medicine, New Haven, Connecticut, USA
| | - Anil K Madugundu
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States; McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States; Currently at the Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, United States
| | - Raja Sekhar Nirujogi
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States; McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States; Currently at the Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Raiha Tahir
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States; Biochemistry, Cellular and Molecular Biology Graduate Program, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States; Currently at Ginkgo Bioworks, Massachusetts, United States
| | - Robert Cole
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States; The Mass Spectrometry and Proteomics Facility, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Akhilesh Pandey
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States; McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States; Currently at the Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, United States; Currently at the Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, United States; Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Natasha E Zachara
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States; Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States.
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Herzog R, Bartosova M, Tarantino S, Wagner A, Unterwurzacher M, Sacnun JM, Lichtenauer AM, Kuster L, Schaefer B, Alper SL, Aufricht C, Schmitt CP, Kratochwill K. Peritoneal Dialysis Fluid Supplementation with Alanyl-Glutamine Attenuates Conventional Dialysis Fluid-Mediated Endothelial Cell Injury by Restoring Perturbed Cytoprotective Responses. Biomolecules 2020; 10:biom10121678. [PMID: 33334074 PMCID: PMC7765520 DOI: 10.3390/biom10121678] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/09/2020] [Accepted: 12/12/2020] [Indexed: 12/18/2022] Open
Abstract
Long-term clinical outcome of peritoneal dialysis (PD) depends on adequate removal of small solutes and water. The peritoneal endothelium represents the key barrier and peritoneal transport dysfunction is associated with vascular changes. Alanyl-glutamine (AlaGln) has been shown to counteract PD-induced deteriorations but the effect on vascular changes has not yet been elucidated. Using multiplexed proteomic and bioinformatic analyses we investigated the molecular mechanisms of vascular pathology in-vitro (primary human umbilical vein endothelial cells, HUVEC) and ex-vivo (arterioles of patients undergoing PD) following exposure to PD-fluid. An overlap of 1813 proteins (40%) of over 3100 proteins was identified in both sample types. PD-fluid treatment significantly altered 378 in endothelial cells and 192 in arterioles. The HUVEC proteome resembles the arteriolar proteome with expected sample specific differences of mainly immune system processes only present in arterioles and extracellular region proteins primarily found in HUVEC. AlaGln-addition to PD-fluid revealed 359 differentially abundant proteins and restored the molecular process landscape altered by PD fluid. This study provides evidence on validity and inherent limitations of studying endothelial pathomechanisms in-vitro compared to vascular ex-vivo findings. AlaGln could reduce PD-associated vasculopathy by reducing endothelial cellular damage, restoring perturbed abundances of pathologically important proteins and enriching protective processes.
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Affiliation(s)
- Rebecca Herzog
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, 1090 Vienna, Austria; (R.H.); (S.T.); (J.M.S.); (A.M.L.); (L.K.); (C.A.)
- Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Medical University of Vienna, 1090 Vienna, Austria; (A.W.); (M.U.)
| | - Maria Bartosova
- Center for Pediatric and Adolescent Medicine, University of Heidelberg, 69120 Heidelberg, Germany; (M.B.); (B.S.); (C.P.S.)
| | - Silvia Tarantino
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, 1090 Vienna, Austria; (R.H.); (S.T.); (J.M.S.); (A.M.L.); (L.K.); (C.A.)
- Zytoprotec GmbH, 1090 Vienna, Austria
| | - Anja Wagner
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, 1090 Vienna, Austria; (R.H.); (S.T.); (J.M.S.); (A.M.L.); (L.K.); (C.A.)
- Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Medical University of Vienna, 1090 Vienna, Austria; (A.W.); (M.U.)
| | - Markus Unterwurzacher
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, 1090 Vienna, Austria; (R.H.); (S.T.); (J.M.S.); (A.M.L.); (L.K.); (C.A.)
- Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Medical University of Vienna, 1090 Vienna, Austria; (A.W.); (M.U.)
| | - Juan Manuel Sacnun
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, 1090 Vienna, Austria; (R.H.); (S.T.); (J.M.S.); (A.M.L.); (L.K.); (C.A.)
- Zytoprotec GmbH, 1090 Vienna, Austria
| | - Anton M. Lichtenauer
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, 1090 Vienna, Austria; (R.H.); (S.T.); (J.M.S.); (A.M.L.); (L.K.); (C.A.)
| | - Lilian Kuster
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, 1090 Vienna, Austria; (R.H.); (S.T.); (J.M.S.); (A.M.L.); (L.K.); (C.A.)
| | - Betti Schaefer
- Center for Pediatric and Adolescent Medicine, University of Heidelberg, 69120 Heidelberg, Germany; (M.B.); (B.S.); (C.P.S.)
| | - Seth L. Alper
- Division of Nephrology and Center for Vascular Biology Research, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA;
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Christoph Aufricht
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, 1090 Vienna, Austria; (R.H.); (S.T.); (J.M.S.); (A.M.L.); (L.K.); (C.A.)
| | - Claus Peter Schmitt
- Center for Pediatric and Adolescent Medicine, University of Heidelberg, 69120 Heidelberg, Germany; (M.B.); (B.S.); (C.P.S.)
| | - Klaus Kratochwill
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, 1090 Vienna, Austria; (R.H.); (S.T.); (J.M.S.); (A.M.L.); (L.K.); (C.A.)
- Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Medical University of Vienna, 1090 Vienna, Austria; (A.W.); (M.U.)
- Correspondence: ; Tel.: +43-140400-80
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Herzog R, Wagner A, Wrettos G, Stampf K, Bromberger S, Sperl E, Kratochwill K. Improved Alignment and Quantification of Protein Signals in Two-Dimensional Western Blotting. J Proteome Res 2020; 19:2379-2390. [PMID: 32402202 DOI: 10.1021/acs.jproteome.0c00061] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Western blotting is widely used for protein identification and quantification in research applications, but different protein species, resulting from alternative splicing and post-translational modifications, can often only be detected individually by two-dimensional gel electrophoresis and immunodetection by Western blotting (2D-WB). The additional separation by isoelectric focusing enables the detection of different protein species with the same specific antibody. Reliable assignment of signals from antibody-based detection to the total protein spot pattern of the original gel image is a challenge in 2D-WB, often resulting in ambiguous results. We therefore propose a reliable strategy for assignment of antibody signals from 2D-WB to the total protein spot pattern, using an imaging workflow in combination with a straightforward and easily reproducible image alignment strategy. The strategy employs vector-based alignment of protein spots and image contours in a stepwise manner. Our workflow is compatible with various protein visualization techniques, including prelabeling of proteins and poststaining of gels and membranes, as well as with chemiluminescent and fluorescent detection of bound antibody. Here, we provide a detailed description of potential applications and benefits of our workflow. We use experimental test settings with gold-standard stressors in combination with multiple staining and detection methods, as well as spike-in recombinant proteins. Our results demonstrate reliable attribution of signals to very similar heat shock proteins, phosphorylation patterns, and global analysis of proteins modified with O-linked N-acetylglucosamine (O-GlcNAc).
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Affiliation(s)
- Rebecca Herzog
- Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, 1090 Vienna, Austria.,Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University, 1090 Vienna, Austria
| | - Anja Wagner
- Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, 1090 Vienna, Austria.,Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University, 1090 Vienna, Austria
| | | | - Kathrin Stampf
- Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, 1090 Vienna, Austria
| | - Sophie Bromberger
- Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, 1090 Vienna, Austria
| | - Eva Sperl
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University, 1090 Vienna, Austria
| | - Klaus Kratochwill
- Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, 1090 Vienna, Austria.,Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University, 1090 Vienna, Austria
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8
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Liang H, Xu L, Gao A, Shao Y, Yang S, Jiang Z, Ma W, Zhu S, Lin T, Zhang X. Upregulated protein O-GlcNAcylation promoted functional and structural recovery of the contused spinal cord injury in rats by Thiamet-G treatment. Neurol Res 2019; 41:780-790. [PMID: 31092134 DOI: 10.1080/01616412.2019.1611202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Objectives-Elevated protein O-GlcNAcylation could benefit cell survival and promote organ functional recovery. Thiamet-G (O-GlcNAcase inhibitor) could upregulate protein O-GlcNAcylation level to improve dyskinesia in models of neurodegenerative diseases without any obvious detrimental side-effects. Therefore, we conducted this study to investigate the effects of protein O-GlcNAcylation upregulation by Thiamet-G on the spinal cord injury (SCI) in rats. Methods-We randomly assigned 74 rats to three groups: sham-operated group (Sham) with no lesion (n = 22), injured control group (SCI+SS) with saline solution (n = 26), and Thiamet-G treated group (SCI+Thiamet-G) (n = 26). We assessed Locomotor behavior using the Basso, Beattice, and Bresnahan (BBB) scale and evaluated histopathological alterations by morphometry and histochemistry. We also assessed potential inflammatory effects by microglia/macrophages immunohistochemistry, and potential apoptosis effects by caspase-3 western blot. Results-Thiamet-G treatment improved hindlimb motor functional recovery by inducing elevated protein O-GlcNAcylation, and mitigated the severity, reduced the lesion size and promoted the structural recovery of the injured spinal cord. Thiamet-G treatment also inhibited microglia/macrophages infiltration at the injury sites and the caspase-3 mediated apoptosis pathway. Discussion-We conclude that Thiamet-G induced elevated protein O-GlcNAcylation to ameliorate acute SCI, which could provide a potential novel therapeutic approach for SCI treatment.
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Affiliation(s)
- Hongsheng Liang
- Department of Neurosurgery, First Affiliated Hospital, Harbin Medical University , Harbin , China
| | - Lin Xu
- Department of Neurosurgery, First Affiliated Hospital, Harbin Medical University , Harbin , China.,Department of Neurology, First Affiliated Hospital, Harbin Medical University , Harbin , China
| | - Aili Gao
- Department of Neurosurgery, Zibo No.1 Hospital , Zi bo city , Shandong Province , China
| | - Yongxiang Shao
- School of Life Science, The Northeast Agricultural University , Harbin , China
| | - Shanshan Yang
- Department of Neurosurgery, The Second People's Hospital of Yibin , Sichuan , China
| | - Zhenfeng Jiang
- Department of Neurosurgery, First Affiliated Hospital, Harbin Medical University , Harbin , China
| | - Wei Ma
- Department of Neurosurgery, First Affiliated Hospital, Harbin Medical University , Harbin , China
| | - Shiyi Zhu
- Department of Neurosurgery, First Affiliated Hospital, Harbin Medical University , Harbin , China
| | - Tie Lin
- Department of Neurosurgery, First Affiliated Hospital, Harbin Medical University , Harbin , China
| | - Xiangtong Zhang
- Department of Neurosurgery, First Affiliated Hospital, Harbin Medical University , Harbin , China
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9
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Boehm M, Herzog R, Klinglmüller F, Lichtenauer AM, Wagner A, Unterwurzacher M, Beelen RHJ, Alper SL, Aufricht C, Kratochwill K. The Peritoneal Surface Proteome in a Model of Chronic Peritoneal Dialysis Reveals Mechanisms of Membrane Damage and Preservation. Front Physiol 2019; 10:472. [PMID: 31156443 PMCID: PMC6530346 DOI: 10.3389/fphys.2019.00472] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 04/04/2019] [Indexed: 12/31/2022] Open
Abstract
Peritoneal dialysis (PD) fluids are cytotoxic to the peritoneum. Recent studies have shown that alanyl-glutamine (AlaGln) modulates the cellular stress response, improves mesothelial cell survival, reduces submesothelial thickening in experimental models of PD, and in clinical studies improves PD effluent cell stress and immune responses. However, the mechanisms of AlaGln-mediated membrane protection are not yet fully understood. Here, we explore those mechanisms through application of a novel proteomics approach in a clinically relevant in vivo model in rats. Experimental PD was performed for 5 weeks using conventional single-chamber bag (SCB) or neutral dual-chamber bag (DCB), PD fluid (PDF), with or without AlaGln supplementation, via a surgically implanted catheter. Rats subjected to a single dwell without catheter implantation served as controls. The peritoneal surface proteome was directly harvested by detergent extraction and subjected to proteomic analysis by two-dimensional difference gel electrophoresis (2D-DiGE) with protein identification by mass spectrometry. An integrated bioinformatic approach was applied to identify proteins significantly affected by the treatments despite biological variation and interfering high abundance proteins. From 505 of 744 common spots on 59 gels, 222 unique proteins were identified. Using UniProt database information, proteins were assigned either as high abundance plasma proteins, or as cellular proteins. Statistical analysis employed an adapted workflow from RNA-sequencing, the trimmed mean of M-values (TMM) for normalization, and a mixed model for computational identification of significantly differentially abundant proteins. The most prominently enriched pathways after 5 weeks chronic treatment with SCB or DCB, PDFs belonged to clusters reflecting tissue damage and cell differentiation by cytoskeletal reorganization, immune responses, altered metabolism, and oxidative stress and redox homeostasis. Although the AlaGln effect was not as prominent, associated enriched pathways showed mostly regression to control or patterns opposite that of the PDF effect. Our study describes the novel peritoneal surface proteome through combined proteomic and bioinformatic analyses, and assesses changes elicited by chronic experimental PD. The biological processes so identified promise to link molecular mechanisms of membrane damage and protection in the in vivo rat model to pathomechanisms and cytoprotective effects observed in vitro and in clinical PD.
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Affiliation(s)
- Michael Boehm
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Rebecca Herzog
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.,Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Florian Klinglmüller
- Center for Medical Statistics, Informatics, and Intelligent Systems-CeMSIIS, Medical University of Vienna, Vienna, Austria
| | - Anton M Lichtenauer
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Anja Wagner
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.,Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Markus Unterwurzacher
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.,Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Robert H J Beelen
- Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, Netherlands
| | - Seth L Alper
- Division of Nephrology, Beth Israel Deaconess Medical Center, Boston, MA, United States.,Department of Medicine, Harvard Medical School, Boston, MA, United States
| | - Christoph Aufricht
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Klaus Kratochwill
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.,Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
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10
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Wiesenhofer FM, Herzog R, Boehm M, Wagner A, Unterwurzacher M, Kasper DC, Alper SL, Vychytil A, Aufricht C, Kratochwill K. Targeted Metabolomic Profiling of Peritoneal Dialysis Effluents Shows Anti-oxidative Capacity of Alanyl-Glutamine. Front Physiol 2019; 9:1961. [PMID: 30719009 PMCID: PMC6348277 DOI: 10.3389/fphys.2018.01961] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 12/28/2018] [Indexed: 01/25/2023] Open
Abstract
Readily available peritoneal dialysis (PD) effluents from PD patients in the course of renal replacement therapy are a potentially rich source for molecular markers for predicting clinical outcome, monitoring the therapy, and therapeutic interventions. The complex clinical phenotype of PD patients might be reflected in the PD effluent metabolome. Metabolomic analysis of PD effluent might allow quantitative detection and assessment of candidate PD biomarkers for prognostication and therapeutic monitoring. We therefore subjected peritoneal equilibration test effluents from 20 stable PD patients, obtained in a randomized controlled trial (RCT) to evaluate cytoprotective effects of standard PD solution (3.86% glucose) supplemented with 8 mM alanyl-glutamine (AlaGln) to targeted metabolomics analysis. One hundred eighty eight pre-defined metabolites, including free amino acids, acylcarnitines, and glycerophospholipids, as well as custom metabolic indicators calculated from these metabolites were surveyed in a high-throughput assay requiring only 10 μl of PD effluent. Metabolite profiles of effluents from the cross-over trial were analyzed with respect to AlaGln status and clinical parameters such as duration of PD therapy and history of previous episodes of peritonitis. This targeted approach detected and quantified 184 small molecules in PD effluent, a larger number of detected metabolites than in all previous metabolomic studies in PD effluent combined. Metabolites were clustered within substance classes regarding concentrations after a 4-h dwell. PD effluent metabolic profiles were differentiated according to PD patient sub-populations, revealing novel changes in small molecule abundance during PD therapy. AlaGln supplementation of PD fluid altered levels of specific metabolites, including increases in alanine and glutamine but not glutamate, and reduced levels of small molecule indicators of oxidative stress, such as methionine sulfoxide. Our study represents the first application of targeted metabolomics to PD effluents. The observed metabolomic changes in PD effluent associated with AlaGln-supplementation during therapy suggested an anti-oxidant effect, and were consistent with the restoration of important stress and immune processes previously noted in the RCT. High-throughput detection of PD effluent metabolomic signatures and their alterations by therapeutic interventions offers new opportunities for metabolome-clinical correlation in PD and for prescription of personalized PD therapy.
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Affiliation(s)
- Florian M Wiesenhofer
- Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.,Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Rebecca Herzog
- Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.,Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Michael Boehm
- Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Anja Wagner
- Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.,Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Markus Unterwurzacher
- Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.,Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | | | - Seth L Alper
- Division of Nephrology and Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, MA, United States.,Department of Medicine, Harvard Medical School, Boston, MA, United States
| | - Andreas Vychytil
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Christoph Aufricht
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Klaus Kratochwill
- Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.,Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
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11
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Vychytil A, Herzog R, Probst P, Ribitsch W, Lhotta K, Machold-Fabrizii V, Wiesholzer M, Kaufmann M, Salmhofer H, Windpessl M, Rosenkranz AR, Oberbauer R, König F, Kratochwill K, Aufricht C. A randomized controlled trial of alanyl-glutamine supplementation in peritoneal dialysis fluid to assess impact on biomarkers of peritoneal health. Kidney Int 2018; 94:1227-1237. [PMID: 30360960 DOI: 10.1016/j.kint.2018.08.031] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 07/25/2018] [Accepted: 08/09/2018] [Indexed: 01/26/2023]
Abstract
In early clinical testing, acute addition of alanyl-glutamine (AlaGln) to glucose-based peritoneal dialysis (PD) fluids restored peritoneal cellular stress responses and leukocyte function. This study was designed to test the effect of extended treatment with AlaGln-supplemented PD fluid on biomarkers of peritoneal health. In a double-blinded, randomized crossover design, stable PD patients were treated with AlaGln (8 mM) or placebo added to PD fluid for eight weeks. As primary outcome measures, dialysate cancer-antigen 125 (CA-125) appearance rate and ex vivo stimulated interleukin-6 (IL-6) release were assessed in peritoneal equilibration tests. In 8 Austrian centers, 54 patients were screened, 50 randomized, and 41 included in the full analysis set. AlaGln supplementation significantly increased CA-125 appearance rate and ex vivo stimulated IL-6 release. AlaGln supplementation also reduced peritoneal protein loss, increased ex vivo stimulated tumor necrosis factor (TNF)-α release, and reduced systemic IL-8 levels. No adverse safety signals were observed. All 4 peritonitis episodes occurred during standard PD fluid treatment. A novel AlaGln-supplemented PD fluid improves biomarkers of peritoneal membrane integrity, immune competence, and systemic inflammation compared to unsupplemented PD fluid with neutral pH and low-glucose degradation. A phase 3 trial is needed to determine the impact of AlaGln supplementation on hard clinical outcomes.
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Affiliation(s)
- Andreas Vychytil
- Department of Medicine III, Division of Nephrology and Dialysis, Medical University of Vienna, Vienna, Austria.
| | - Rebecca Herzog
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Nephrology and Gastroenterology, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Medical University of Vienna, Vienna, Austria
| | - Paul Probst
- Department of Medicine III, Division of Nephrology and Dialysis, Medical University of Vienna, Vienna, Austria
| | - Werner Ribitsch
- Department of Internal Medicine, Clinical Division of Nephrology, Medical University of Graz, Graz, Austria
| | - Karl Lhotta
- Department of Internal Medicine 3 (Nephrology and Dialysis), Feldkirch Academic Teaching Hospital, Feldkirch, Austria
| | | | - Martin Wiesholzer
- Department of Internal Medicine I, University Hospital St. Poelten, Karl Landsteiner University of Health Sciences, St. Poelten, Austria
| | - Michaela Kaufmann
- Department of Medicine III, Nephrology, Transplantation, Rheumatology, Geriatrics, Ordensklinikum Linz, Krankenhaus der Elisabethinen Linz, Linz, Austria
| | - Hermann Salmhofer
- Department of Medicine I, Paracelsus Medical University, Salzburg, Austria
| | - Martin Windpessl
- Department of Internal Medicine IV, Klinikum Wels-Grieskirchen, Wels, Austria
| | - Alexander R Rosenkranz
- Department of Internal Medicine, Clinical Division of Nephrology, Medical University of Graz, Graz, Austria
| | - Rainer Oberbauer
- Department of Medicine III, Division of Nephrology and Dialysis, Medical University of Vienna, Vienna, Austria
| | - Franz König
- Center for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - Klaus Kratochwill
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Nephrology and Gastroenterology, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Medical University of Vienna, Vienna, Austria
| | - Christoph Aufricht
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Nephrology and Gastroenterology, Medical University of Vienna, Vienna, Austria
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12
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Recent advances in the applications of metabolomics in eye research. Anal Chim Acta 2018; 1037:28-40. [PMID: 30292303 DOI: 10.1016/j.aca.2018.01.060] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 01/26/2018] [Accepted: 01/29/2018] [Indexed: 11/21/2022]
Abstract
Metabolomics, the identification and quantitation of metabolites in a system, have been applied to identify new biomarkers or elucidate disease mechanism. In this review, we discussed the application of metabolomics in several ocular diseases and recent developments in metabolomics regarding tear fluids analysis, data acquisition and processing.
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13
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Abstract
Peritoneal dialysis (PD) is a successfully used method for renal replacement therapy. However, long-term PD may be associated with peritoneal fibrosis and ultrafiltration failure. The key factors linked to their appearance are repeated episodes of inflammation associated with peritonitis and long-term exposure to bioincompatible PD fluids. Different strategies have been proposed to preserve the peritoneal membrane. This article reviews the functional and structural alterations related to PD and strategies whereby we may prevent them to preserve the peritoneal membrane. The use of new, more biocompatible, PD solutions is promising, although further morphologic studies in patients using these solutions are needed. Blockade of the renin-angiotensin-aldosterone system appears to be efficacious and strongly should be considered. Other agents have been proven in experimental studies, but most of them have not yet been tested appropriately in human beings.
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Affiliation(s)
- M Auxiliadora Bajo
- Home Dialysis Unit, Nephrology Department, La Paz University Hospital, Madrid, Spain.
| | - Gloria Del Peso
- University Autónoma of Madrid, Hospital La Paz Institute for Health Research, Spanish Renal Research Network, Reina Sofia Institute for Nephrology Research, Madrid, Spain
| | - Isaac Teitelbaum
- Home Dialysis Program, University of Colorado Hospital, University of Colorado School of Medicine, Aurora, CO
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14
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Herzog R, Boehm M, Unterwurzacher M, Wagner A, Parapatics K, Májek P, Mueller AC, Lichtenauer A, Bennett KL, Alper SL, Vychytil A, Aufricht C, Kratochwill K. Effects of Alanyl-Glutamine Treatment on the Peritoneal Dialysis Effluent Proteome Reveal Pathomechanism-Associated Molecular Signatures. Mol Cell Proteomics 2017; 17:516-532. [PMID: 29208752 PMCID: PMC5836375 DOI: 10.1074/mcp.ra117.000186] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 11/16/2017] [Indexed: 12/21/2022] Open
Abstract
Peritoneal dialysis (PD) is a modality of renal replacement therapy in which the high volumes of available PD effluent (PDE) represents a rich source of biomarkers for monitoring disease and therapy. Although this information could help guide the management of PD patients, little is known about the potential of PDE to define pathomechanism-associated molecular signatures in PD. We therefore subjected PDE to a high-performance multiplex proteomic analysis after depletion of highly-abundant plasma proteins and enrichment of low-abundance proteins. A combination of label-free and isobaric labeling strategies was applied to PDE samples from PD patients (n = 20) treated in an open-label, randomized, two-period, cross-over clinical trial with standard PD fluid or with a novel PD fluid supplemented with alanyl-glutamine (AlaGln). With this workflow we identified 2506 unique proteins in the PDE proteome, greatly increasing coverage beyond the 171 previously-reported proteins. The proteins identified range from high abundance plasma proteins to low abundance cellular proteins, and are linked to larger numbers of biological processes and pathways, some of which are novel for PDE. Interestingly, proteins linked to membrane remodeling and fibrosis are overrepresented in PDE compared with plasma, whereas the proteins underrepresented in PDE suggest decreases in host defense, immune-competence and response to stress. Treatment with AlaGln-supplemented PD fluid is associated with reduced activity of membrane injury-associated mechanisms and with restoration of biological processes involved in stress responses and host defense. Our study represents the first application of the PDE proteome in a randomized controlled prospective clinical trial of PD. This novel proteomic workflow allowed detection of low abundance biomarkers to define pathomechanism-associated molecular signatures in PD and their alterations by a novel therapeutic intervention.
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Affiliation(s)
- Rebecca Herzog
- From the ‡Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.,§Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Michael Boehm
- From the ‡Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Markus Unterwurzacher
- From the ‡Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.,§Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Anja Wagner
- From the ‡Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.,§Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Katja Parapatics
- ¶CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Peter Májek
- ¶CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - André C Mueller
- ¶CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Anton Lichtenauer
- From the ‡Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Keiryn L Bennett
- ¶CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Seth L Alper
- ‖Division of Nephrology, Beth Israel Deaconess Medical Center, Boston, Massachusetts.,**Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Andreas Vychytil
- ‡‡Department of Medicine III, Division of Nephrology and Dialysis, Medical University of Vienna, Vienna, Austria
| | - Christoph Aufricht
- From the ‡Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Klaus Kratochwill
- From the ‡Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria; .,§Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
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15
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Biomarker research to improve clinical outcomes of peritoneal dialysis: consensus of the European Training and Research in Peritoneal Dialysis (EuTRiPD) network. Kidney Int 2017; 92:824-835. [PMID: 28797473 DOI: 10.1016/j.kint.2017.02.037] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 02/16/2017] [Accepted: 02/27/2017] [Indexed: 12/15/2022]
Abstract
Peritoneal dialysis (PD) therapy substantially requires biomarkers as tools to identify patients who are at the highest risk for PD-related complications and to guide personalized interventions that may improve clinical outcome in the individual patient. In this consensus article, members of the European Training and Research in Peritoneal Dialysis Network (EuTRiPD) review the current status of biomarker research in PD and suggest a selection of biomarkers that can be relevant to the care of PD patients and that are directly accessible in PD effluents. Currently used biomarkers such as interleukin-6, interleukin-8, ex vivo-stimulated interleukin-6 release, cancer antigen-125, and advanced oxidation protein products that were collected through a Delphi procedure were first triaged for inclusion as surrogate endpoints in a clinical trial. Next, novel biomarkers were selected as promising candidates for proof-of-concept studies and were differentiated into inflammation signatures (including interleukin-17, M1/M2 macrophages, and regulatory T cell/T helper 17), mesothelial-to-mesenchymal transition signatures (including microRNA-21 and microRNA-31), and signatures for senescence and inadequate cellular stress responses. Finally, the need for defining pathogen-specific immune fingerprints and phenotype-associated molecular signatures utilizing effluents from the clinical cohorts of PD patients and "omics" technologies and bioinformatics-biostatistics in future joint-research efforts was expressed. Biomarker research in PD offers the potential to develop valuable tools for improving patient management. However, for all biomarkers discussed in this consensus article, the association of biological rationales with relevant clinical outcomes remains to be rigorously validated in adequately powered, prospective, independent clinical studies.
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16
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Stress-induced O-GlcNAcylation: an adaptive process of injured cells. Biochem Soc Trans 2017; 45:237-249. [PMID: 28202678 DOI: 10.1042/bst20160153] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 11/30/2016] [Accepted: 12/14/2016] [Indexed: 02/07/2023]
Abstract
In the 30 years, since the discovery of nucleocytoplasmic glycosylation, O-GlcNAc has been implicated in regulating cellular processes as diverse as protein folding, localization, degradation, activity, post-translational modifications, and interactions. The cell co-ordinates these molecular events, on thousands of cellular proteins, in concert with environmental and physiological cues to fine-tune epigenetics, transcription, translation, signal transduction, cell cycle, and metabolism. The cellular stress response is no exception: diverse forms of injury result in dynamic changes to the O-GlcNAc subproteome that promote survival. In this review, we discuss the biosynthesis of O-GlcNAc, the mechanisms by which O-GlcNAc promotes cytoprotection, and the clinical significance of these data.
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17
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Kratochwill K, Boehm M, Herzog R, Gruber K, Lichtenauer AM, Kuster L, Csaicsich D, Gleiss A, Alper SL, Aufricht C, Vychytil A. Addition of Alanyl-Glutamine to Dialysis Fluid Restores Peritoneal Cellular Stress Responses - A First-In-Man Trial. PLoS One 2016; 11:e0165045. [PMID: 27768727 PMCID: PMC5074513 DOI: 10.1371/journal.pone.0165045] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 10/01/2016] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Peritonitis and ultrafiltration failure remain serious complications of chronic peritoneal dialysis (PD). Dysfunctional cellular stress responses aggravate peritoneal injury associated with PD fluid exposure, potentially due to peritoneal glutamine depletion. In this randomized cross-over phase I/II trial we investigated cytoprotective effects of alanyl-glutamine (AlaGln) addition to glucose-based PDF. METHODS In a prospective randomized cross-over design, 20 stable PD outpatients underwent paired peritoneal equilibration tests 4 weeks apart, using conventional acidic, single chamber 3.86% glucose PD fluid, with and without 8 mM supplemental AlaGln. Heat-shock protein 72 expression was assessed in peritoneal effluent cells as surrogate parameter of cellular stress responses, complemented by metabolomics and functional immunocompetence assays. RESULTS AlaGln restored peritoneal glutamine levels and increased the primary outcome heat-shock protein expression (effect 1.51-fold, CI 1.07-2.14; p = 0.022), without changes in peritoneal ultrafiltration, small solute transport, or biomarkers reflecting cell mass and inflammation. Further effects were glutamine-like metabolomic changes and increased ex-vivo LPS-stimulated cytokine release from healthy donor peripheral blood monocytes. In patients with a history of peritonitis (5 of 20), AlaGln supplementation decreased dialysate interleukin-8 levels. Supplemented PD fluid also attenuated inflammation and enhanced stimulated cytokine release in a mouse model of PD-associated peritonitis. CONCLUSION We conclude that AlaGln-supplemented, glucose-based PD fluid can restore peritoneal cellular stress responses with attenuation of sterile inflammation, and may improve peritoneal host-defense in the setting of PD.
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Affiliation(s)
- Klaus Kratochwill
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
- Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
- Zytoprotec GmbH, Vienna, Austria
| | - Michael Boehm
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Rebecca Herzog
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
- Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
- Zytoprotec GmbH, Vienna, Austria
| | - Katharina Gruber
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Anton Michael Lichtenauer
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
- Zytoprotec GmbH, Vienna, Austria
| | - Lilian Kuster
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
- Zytoprotec GmbH, Vienna, Austria
| | - Dagmar Csaicsich
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Andreas Gleiss
- Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - Seth L. Alper
- Division of Nephrology and Center for Vascular Biology Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Christoph Aufricht
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Andreas Vychytil
- Division of Nephrology and Dialysis, Medical University of Vienna, Vienna, Austria
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18
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Activation of salt-inducible kinase 2 promotes the viability of peritoneal mesothelial cells exposed to stress of peritoneal dialysis. Cell Death Dis 2016; 7:e2298. [PMID: 27441650 PMCID: PMC4973365 DOI: 10.1038/cddis.2016.79] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 02/26/2016] [Accepted: 03/01/2016] [Indexed: 12/19/2022]
Abstract
Maintaining mesothelial cell viability is critical to long-term successful peritoneal dialysis (PD) treatment. To clarify the viability mechanism of peritoneal mesothelial cells under PD solutions exposure, we examined the mechanisms of cellular response to this stress conditions. Here we report that the proteasome activity is inhibited when treated with PD solutions. Proteasome inhibition-mediated activation of salt-inducible kinase 2 (SIK2), an endoplasmic reticulum-resident protein, is important for mesothelial cell viability. SIK2 is mobilized to promote autophagy and protect the cells from apoptosis under PD solution or MG132 treatment. Immunofluorescence staining showed that SIK2 is colocalized with LC3B in the autophagosomes of mesothelial cells treated with PD solution or derived from patients undergoing PD treatment. SIK2 activation is likely via a two-step mechanism, upstream kinases relieving the autoinhibitory conformation of SIK2 molecule followed by autophosphorylation of Thr175 and activation of kinase activity. These results suggest that activation of SIK2 is required for the cell viability when proteasome activity is inhibited by PD solutions. Maintaining or boosting the activity of SIK2 may promote peritoneal mesothelial cell viability and evolve as a potential therapeutic target for maintaining or restoring peritoneal membrane integrity in PD therapy.
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19
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Senescence-Associated Changes in Proteome and O-GlcNAcylation Pattern in Human Peritoneal Mesothelial Cells. BIOMED RESEARCH INTERNATIONAL 2015; 2015:382652. [PMID: 26640786 PMCID: PMC4657062 DOI: 10.1155/2015/382652] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 10/24/2015] [Accepted: 10/25/2015] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Senescence of peritoneal mesothelial cells represents a biological program defined by arrested cell growth and altered cell secretory phenotype with potential impact in peritoneal dialysis. This study aims to characterize cellular senescence at the level of global protein expression profiles and modification of proteins with O-linked N-acetylglucosamine (O-GlcNAcylation). METHODS A comparative proteomics analysis between young and senescent human peritoneal mesothelial cells (HPMC) was performed using two-dimensional gel electrophoresis. O-GlcNAc status was assessed by Western blot under normal conditions and after modulation with 6-diazo-5-oxo-L-norleucine (DON) to decrease O-GlcNAcylation or O-(2-acetamido-2-deoxy-D-glucopyranosylidene) amino N-phenyl carbamate (PUGNAc) to increase O-GlcNAcylation. RESULTS Comparison of protein pattern of senescent and young HPMC revealed 29 differentially abundant protein spots, 11 of which were identified to be actin (cytoplasmic 1 and 2), cytokeratin-7, cofilin-2, transgelin-2, Hsp60, Hsc70, proteasome β-subunits (type-2 and type-3), nucleoside diphosphate kinase A, and cytosolic 5'(3')-deoxyribonucleotidase. Although the global level of O-GlcNAcylation was comparable, senescent cells were not sensitive to modulation by PUGNAc. DISCUSSION This study identified changes of the proteome and altered dynamics of O-GlcNAc regulation in senescent mesothelial cells. Whereas changes in cytoskeleton-associated proteins likely reflect altered cell morphology, changes in chaperoning and housekeeping proteins may have functional impact on cellular stress response in peritoneal dialysis.
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20
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Cross-omics comparison of stress responses in mesothelial cells exposed to heat- versus filter-sterilized peritoneal dialysis fluids. BIOMED RESEARCH INTERNATIONAL 2015; 2015:628158. [PMID: 26495307 PMCID: PMC4606138 DOI: 10.1155/2015/628158] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 08/31/2015] [Indexed: 02/06/2023]
Abstract
Recent research suggests that cytoprotective responses, such as expression of heat-shock proteins, might be inadequately induced in mesothelial cells by heat-sterilized peritoneal dialysis (PD) fluids. This study compares transcriptome data and multiple protein expression profiles for providing new insight into regulatory mechanisms. Two-dimensional difference gel electrophoresis (2D-DIGE) based proteomics and topic defined gene expression microarray-based transcriptomics techniques were used to evaluate stress responses in human omental peritoneal mesothelial cells in response to heat- or filter-sterilized PD fluids. Data from selected heat-shock proteins were validated by 2D western-blot analysis. Comparison of proteomics and transcriptomics data discriminated differentially regulated protein abundance into groups depending on correlating or noncorrelating transcripts. Inadequate abundance of several heat-shock proteins following exposure to heat-sterilized PD fluids is not reflected on the mRNA level indicating interference beyond transcriptional regulation. For the first time, this study describes evidence for posttranscriptional inadequacy of heat-shock protein expression by heat-sterilized PD fluids as a novel cytotoxic property. Cross-omics technologies introduce a novel way of understanding PDF bioincompatibility and searching for new interventions to reestablish adequate cytoprotective responses.
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Chen L, Li J, Guo T, Ghosh S, Koh SK, Tian D, Zhang L, Jia D, Beuerman RW, Aebersold R, Chan ECY, Zhou L. Global Metabonomic and Proteomic Analysis of Human Conjunctival Epithelial Cells (IOBA-NHC) in Response to Hyperosmotic Stress. J Proteome Res 2015; 14:3982-95. [PMID: 26260330 DOI: 10.1021/acs.jproteome.5b00443] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
"Dry eye" is a multifactorial inflammatory disease affecting the ocular surface. Tear hyperosmolarity in dry eye contributes to inflammation and cell damage. Recent research efforts on dry eye have been directed toward biomarker discovery for diagnosis, response to treatment, and disease mechanisms. This study employed a spontaneously immortalized normal human conjunctival cell line, IOBA-NHC, as a model to investigate hyperosmotic stress-induced changes of metabolites and proteins. Global and targeted metabonomic analyses as well as proteomic analysis were performed on IOBA-NHC cells incubated in serum-free media at 280 (control), 380, and 480 mOsm for 24 h. Twenty-one metabolites and seventy-six iTRAQ-identified proteins showed significant changes under at least one hyperosmotic stress treatment as compared with controls. SWATH-based proteomic analysis further confirmed the involvement of inflammatory pathways such as prostaglandin 2 synthesis in IOBA-NHC cells under hyperosmotic stress. This study is the first to identify glycerophosphocholine synthesis and O-linked β-N-acetylglucosamine glycosylation as key activated pathways in ocular surface cells under hyperosmotic stress. These findings extend the current knowledge in metabolite markers of dry eye and provide potential therapeutic targets for its treatment.
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Affiliation(s)
- Liyan Chen
- Singapore Eye Research Institute , The Academia, 20 College Road, Discovery Tower Level 6, Singapore 169856, Singapore.,Department of Pharmacy, Faculty of Science, National University of Singapore , 18 Science Drive 4, Singapore 117543, Singapore
| | - Jing Li
- Singapore Eye Research Institute , The Academia, 20 College Road, Discovery Tower Level 6, Singapore 169856, Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore , 1E Kent Ridge Road, NUHS Tower Block Level 7, Singapore 119228, Singapore.,Department of Ophthalmology, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine , 1665 Kongjiang Road, Shanghai 200092, China
| | - Tiannan Guo
- Institute of Molecular Systems Biology, Department of Biology, ETH Zurich , Auguste-Piccard-Hof 1, 8093 Zürich, Switzerland
| | - Sujoy Ghosh
- Cardiovascular and Metabolic Disorders Program & Centre for Computational Biology, Duke-NUS Graduate Medical School , 8 College Road, Singapore 169857, Singapore
| | - Siew Kwan Koh
- Singapore Eye Research Institute , The Academia, 20 College Road, Discovery Tower Level 6, Singapore 169856, Singapore
| | - Dechao Tian
- Singapore Eye Research Institute , The Academia, 20 College Road, Discovery Tower Level 6, Singapore 169856, Singapore.,Department of Statistics and Applied Probability, Faculty of Science, National University of Singapore , 6 Science Drive 2, Singapore 117546, Singapore
| | - Liang Zhang
- Singapore Eye Research Institute , The Academia, 20 College Road, Discovery Tower Level 6, Singapore 169856, Singapore.,Department of Statistics and Applied Probability, Faculty of Science, National University of Singapore , 6 Science Drive 2, Singapore 117546, Singapore
| | - Deyong Jia
- Singapore Eye Research Institute , The Academia, 20 College Road, Discovery Tower Level 6, Singapore 169856, Singapore
| | - Roger W Beuerman
- Singapore Eye Research Institute , The Academia, 20 College Road, Discovery Tower Level 6, Singapore 169856, Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore , 1E Kent Ridge Road, NUHS Tower Block Level 7, Singapore 119228, Singapore.,Neuroscience and Behavioral Disorders Program, Duke-NUS Graduate Medical School , 8 College Road, Singapore 169857, Singapore
| | - Ruedi Aebersold
- Institute of Molecular Systems Biology, Department of Biology, ETH Zurich , Auguste-Piccard-Hof 1, 8093 Zürich, Switzerland.,Faculty of Science, University of Zurich , Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Eric Chun Yong Chan
- Department of Pharmacy, Faculty of Science, National University of Singapore , 18 Science Drive 4, Singapore 117543, Singapore
| | - Lei Zhou
- Singapore Eye Research Institute , The Academia, 20 College Road, Discovery Tower Level 6, Singapore 169856, Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore , 1E Kent Ridge Road, NUHS Tower Block Level 7, Singapore 119228, Singapore.,Neuroscience and Behavioral Disorders Program, Duke-NUS Graduate Medical School , 8 College Road, Singapore 169857, Singapore
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22
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Ditsawanon P, Aramwit P. Preserving the peritoneal membrane in long-term peritoneal dialysis patients. J Clin Pharm Ther 2015; 40:508-516. [PMID: 26280248 DOI: 10.1111/jcpt.12318] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 07/20/2015] [Indexed: 12/24/2022]
Abstract
WHAT IS KNOWN AND OBJECTIVE Peritoneal dialysis (PD) has been widely used by patients with end-stage renal disease. However, chronic exposure of the peritoneal membrane to bioincompatible PD solutions, and peritonitis and uraemia during long-term dialysis result in peritoneal membrane injury and thereby contribute to membrane changes, ultrafiltration (UF) failure, inadequate dialysis and technical failure. Therefore, preserving the peritoneal membrane is important to maintain the efficacy of PD. This article reviews the current literature on therapeutic agents for preserving the peritoneal membrane. METHODS A literature search of PubMed was conducted using the search terms peritoneal fibrosis, peritoneal sclerosis, membrane, integrity, preserve, therapy and peritoneal dialysis, but not including peritonitis. Published clinical trials, in vitro studies, experimental trials in animal models, meta-analyses and review articles were identified and reviewed for relevance. RESULTS AND DISCUSSION We focus on understanding how factors cause peritoneal membrane changes, the characteristics and mechanisms of peritoneal membrane changes in patients undergoing PD and the types of therapeutic agents for peritoneal membrane preservation. There have been many investigations into the preservation of the peritoneal membrane, including PD solution improvement, the inhibition of cytokine and growth factor expression using renin-angiotensin-aldosterone system (RAAS) blockade, glycosaminoglycans (GAGs), L-carnitine and taurine additives. In addition, there are potential future therapeutic agents that are still in experimental investigations. WHAT IS NEW AND CONCLUSION The efficacy of many of the therapeutic agents is uncertain because there are insufficient good-quality clinical studies. Overall membrane preservation and patient survival remain unproven in using more biocompatible PD solutions. With RAAS blockade, results are still inconclusive, as many of the clinical studies were retrospective. With GAGs, L-carnitine and taurine additives, there is no sufficiently long follow-up clinical study with a large sample size to support its efficacy. Therefore, better quality clinical studies within this area should be performed.
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Affiliation(s)
- P Ditsawanon
- Bioactive Resources for Innovative Clinical Applications Research Unit, Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand
| | - P Aramwit
- Bioactive Resources for Innovative Clinical Applications Research Unit, Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand
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