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Dai X, Ma Y, Lin Q, Tang H, Chen R, Zhu Y, Shen Y, Cui N, Hong Z, Li Y, Li X. Clinical features and management of atypical hemolytic uremic syndrome patient with DGKE gene variants: a case report. Front Pediatr 2023; 11:1162974. [PMID: 37456562 PMCID: PMC10340117 DOI: 10.3389/fped.2023.1162974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 06/19/2023] [Indexed: 07/18/2023] Open
Abstract
Background Atypical hemolytic uremic syndrome (aHUS) with diacylglycerol kinase epsilon (DGKE) gene variant is a rare variant of thrombotic microangiopathy (TMA). The information on the clinical features, management and long-term outcomes of DGKE-aHUS patients have not yet been fully elucidated. The aim of this study was to report a novel variant of the DGKE gene in a Chinese population with aHUS. Case presentation The present work reports a 7-month-old boy with aHUS, possibly triggered by gastrointestinal infection, without complement activation, with little response to plasma therapy and nephroprotective measures. The patient died during the 8th week of his hospital stay. The causes of death were intracranial hemorrhage and multiorgan dysfunction. Comprehensive WES of peripheral blood-derived DNA revealed two heterozygous variations in the DGKE exon region: NM_003647.2, c.610dup, p.Thr204Asnfs*4 and deletion of exons 4-6. Conclusions This case suggest that atypical HUS with DGKE gene variant has a poor prognosis with a high mortality rate, which typically manifests in the first year of life and presents as a systemic disease with early-onset HUS with rapidly worsening renal function and chronic proteinuria. There is no specific treatment for DGKE-aHUS. There have an uncertain benefit of plasma therapy for DGKE-aHUS patients. The literature demonstrated that anti-complement therapy showed benefits for DGKE-aHUS with complement activation and autoantibodies during the overt TMA presentation but did not prevent TMA relapses. Early diagnosis and treatment may prevent complications and improve prognosis.
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Affiliation(s)
- Xiaomei Dai
- Department of Nephrology and Immunology, Children’s Hospital of Soochow University, Suzhou, China
| | - Yu Ma
- Department of Respiratory Medicine, Children’s Hospital of Soochow University, Suzhou, China
| | - Qiang Lin
- Department of Nephrology and Immunology, Children’s Hospital of Soochow University, Suzhou, China
| | - Hanyun Tang
- Department of Nephrology and Immunology, Children’s Hospital of Soochow University, Suzhou, China
| | - Ruyue Chen
- Department of Nephrology and Immunology, Children’s Hospital of Soochow University, Suzhou, China
| | - Yun Zhu
- Department of Nephrology and Immunology, Children’s Hospital of Soochow University, Suzhou, China
| | - Yunyan Shen
- Department of Nephrology and Immunology, Children’s Hospital of Soochow University, Suzhou, China
| | - Ningxun Cui
- Department of Nephrology and Immunology, Children’s Hospital of Soochow University, Suzhou, China
| | - Zhongqin Hong
- Department of Nephrology and Immunology, Children’s Hospital of Soochow University, Suzhou, China
| | - Yanhong Li
- Department of Nephrology and Immunology, Children’s Hospital of Soochow University, Suzhou, China
- Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China
| | - Xiaozhong Li
- Department of Nephrology and Immunology, Children’s Hospital of Soochow University, Suzhou, China
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Chen IR, Huang CC, Tu SJ, Wang GJ, Lai PC, Lee YT, Yen JC, Chang YS, Chang JG. Dysregulation of Immune Cell Subpopulations in Atypical Hemolytic Uremic Syndrome. Int J Mol Sci 2023; 24:10007. [PMID: 37373158 DOI: 10.3390/ijms241210007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 05/30/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a rare, life-threatening thrombotic microangiopathy. Definitive biomarkers for disease diagnosis and activity remain elusive, making the exploration of molecular markers paramount. We conducted single-cell sequencing on peripheral blood mononuclear cells from 13 aHUS patients, 3 unaffected family members of aHUS patients, and 4 healthy controls. We identified 32 distinct subpopulations encompassing 5 B-cell types, 16 T- and natural killer (NK) cell types, 7 monocyte types, and 4 other cell types. Notably, we observed a significant increase in intermediate monocytes in unstable aHUS patients. Subclustering analysis revealed seven elevated expression genes, including NEAT1, MT-ATP6, MT-CYB, VIM, ACTG1, RPL13, and KLRB1, in unstable aHUS patients, and four heightened expression genes, including RPS27, RPS4X, RPL23, and GZMH genes, in stable aHUS patients. Additionally, an increase in the expression of mitochondria-related genes suggested a potential influence of cell metabolism on the clinical progression of the disease. Pseudotime trajectory analysis revealed a unique immune cell differentiation pattern, while cell-cell interaction profiling highlighted distinctive signaling pathways among patients, family members, and controls. This single-cell sequencing study is the first to confirm immune cell dysregulation in aHUS pathogenesis, offering valuable insights into molecular mechanisms and potential new diagnostic and disease activity markers.
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Affiliation(s)
- I-Ru Chen
- Graduate Institute of Clinical Medical Science, College of Medicine, China Medical University, Taichung 40402, Taiwan
- Division of Nephrology and the Kidney Institute, Department of Internal Medicine, China Medical University and Hospitals, Taichung 404332, Taiwan
| | - Chiu-Ching Huang
- Graduate Institute of Clinical Medical Science, College of Medicine, China Medical University, Taichung 40402, Taiwan
- Division of Nephrology and the Kidney Institute, Department of Internal Medicine, China Medical University and Hospitals, Taichung 404332, Taiwan
| | - Siang-Jyun Tu
- Center for Precision Medicine, China Medical University Hospital, Taichung 404332, Taiwan
| | - Guei-Jane Wang
- Graduate Institute of Clinical Medical Science, College of Medicine, China Medical University, Taichung 40402, Taiwan
- Department of Medical Research, China Medical University Hospital, Taichung 404332, Taiwan
| | - Ping-Chin Lai
- Division of Nephrology and the Kidney Institute, Department of Internal Medicine, China Medical University and Hospitals, Taichung 404332, Taiwan
| | - Ya-Ting Lee
- Center for Precision Medicine, China Medical University Hospital, Taichung 404332, Taiwan
- Department of Medical Research, China Medical University Hospital, Taichung 404332, Taiwan
- Epigenome Research Center, China Medical University Hospital, Taichung 404332, Taiwan
| | - Ju-Chen Yen
- Center for Precision Medicine, China Medical University Hospital, Taichung 404332, Taiwan
- Department of Medical Research, China Medical University Hospital, Taichung 404332, Taiwan
- Epigenome Research Center, China Medical University Hospital, Taichung 404332, Taiwan
| | - Ya-Sian Chang
- Center for Precision Medicine, China Medical University Hospital, Taichung 404332, Taiwan
- Department of Medical Research, China Medical University Hospital, Taichung 404332, Taiwan
- Epigenome Research Center, China Medical University Hospital, Taichung 404332, Taiwan
| | - Jan-Gowth Chang
- Graduate Institute of Clinical Medical Science, College of Medicine, China Medical University, Taichung 40402, Taiwan
- Center for Precision Medicine, China Medical University Hospital, Taichung 404332, Taiwan
- Department of Medical Research, China Medical University Hospital, Taichung 404332, Taiwan
- Epigenome Research Center, China Medical University Hospital, Taichung 404332, Taiwan
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Michael M, Bagga A, Sartain SE, Smith RJH. Haemolytic uraemic syndrome. Lancet 2022; 400:1722-1740. [PMID: 36272423 DOI: 10.1016/s0140-6736(22)01202-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 06/16/2022] [Accepted: 06/16/2022] [Indexed: 11/05/2022]
Abstract
Haemolytic uraemic syndrome (HUS) is a heterogeneous group of diseases that result in a common pathology, thrombotic microangiopathy, which is classically characterised by the triad of non-immune microangiopathic haemolytic anaemia, thrombocytopenia, and acute kidney injury. In this Seminar, different causes of HUS are discussed, the most common being Shiga toxin-producing Escherichia coli HUS. Identifying the underlying thrombotic microangiopathy trigger can be challenging but is imperative if patients are to receive personalised disease-specific treatment. The quintessential example is complement-mediated HUS, which once carried an extremely high mortality but is now treated with anti-complement therapies with excellent long-term outcomes. Unfortunately, the high cost of anti-complement therapies all but precludes their use in low-income countries. For many other forms of HUS, targeted therapies are yet to be identified.
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Affiliation(s)
- Mini Michael
- Division of Pediatric Nephrology, Baylor College of Medicine, Texas Children's Hospital, Houston, TX, USA.
| | - Arvind Bagga
- Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Sarah E Sartain
- Pediatrics-Hematology/Oncology, Baylor College of Medicine, Houston, TX, USA
| | - Richard J H Smith
- Department of Otolaryngology, Pediatrics and Molecular Physiology & Biophysics, The University of Iowa, Iowa City, IA, USA
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Traczyk G, Świątkowska A, Hromada-Judycka A, Janikiewicz J, Kwiatkowska K. An intact zinc finger motif of the C1B domain is critical for stability and activity of diacylglycerol kinase-ε. Int J Biochem Cell Biol 2022; 152:106295. [PMID: 36113832 DOI: 10.1016/j.biocel.2022.106295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 08/08/2022] [Accepted: 09/08/2022] [Indexed: 10/31/2022]
Abstract
Diacylglycerol kinase-ε (DGKε) phosphorylates DAG to phosphatidic acid with unique specificity toward 18:0/20:4 DAG (SAG). SAG is a typical backbone of phosphatidylinositol and its derivatives, therefore DGKε activity is crucial for the turnover of these signaling lipids. Malfunction of DGKε contributes to several pathophysiological conditions, including atypical hemolytic uremic syndrome (aHUS) linked with DGKE mutations. In the present study we analyzed the role of a zinc finger motif of the C1B domain of DGKε, as some aHUS-linked mutations affect this ill-defined part of the kinase. For this, we introduce a novel fluorescent assay for determination of DGKε activity which relies on the use of NBD-SAG in mixed micelles as a substrate, followed by TLC separation of NBD-phosphatidic acid formed. The assay reliably determines the activity of purified human GST-DGKε, also endogenous DGKε or overexpressed mouse DGKε-Myc in cell lysates, homogenates, and kinase immunoprecipitates. Using the above assay we found that four amino acids, Cys135, Cys138, His161 and Cys164, forming the zinc finger motif in the C1B domain are required for the DGKε-Myc activity and stability. Substitution of any of these amino acids with Ala or Trp in DGKε-Myc abolished its activity and led to its proteasomal degradation, possibly assisted by Hsp70/90/40 chaperones. Inhibition of the 26S proteasome prevented the degradation but the mutated proteins were inactive. The present data on the deleterious effect of the zinc finger motif disruption contribute to the understanding of the DGKε-linked aHUS, as the Cys164Trp substitution in mouse DGKε corresponds to the Cys167Trp one in human DGKε found in some aHUS patients.
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Affiliation(s)
- Gabriela Traczyk
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology PAS, 3 Pasteur St., 02-093 Warsaw, Poland.
| | - Anna Świątkowska
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology PAS, 3 Pasteur St., 02-093 Warsaw, Poland.
| | - Aneta Hromada-Judycka
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology PAS, 3 Pasteur St., 02-093 Warsaw, Poland.
| | - Justyna Janikiewicz
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology PAS, 3 Pasteur St., 02-093 Warsaw, Poland.
| | - Katarzyna Kwiatkowska
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology PAS, 3 Pasteur St., 02-093 Warsaw, Poland.
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Thompson GL, Kavanagh D. Diagnosis and treatment of thrombotic microangiopathy. Int J Lab Hematol 2022; 44 Suppl 1:101-113. [PMID: 36074708 PMCID: PMC9544907 DOI: 10.1111/ijlh.13954] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 07/28/2022] [Indexed: 12/01/2022]
Abstract
Thrombotic microangiopathy (TMA) is characterized by thrombocytopenia, microangiopathic haemolytic anaemia and end organ damage. TMAs have varying underlying pathophysiology and can therefore present with an array of clinical presentations. Renal involvement is common as the kidney is particularly susceptible to the endothelial damage and microvascular occlusion. TMAs require rapid assessment, diagnosis, and commencement of appropriate treatment due to the high morbidity and mortality associated with them. Ground-breaking research into the pathogenesis of TMAs over the past 20 years has driven the successful development of targeted therapeutics revolutionizing patient outcomes. This review outlines the clinical presentations, pathogenesis, diagnostic tests and treatments for TMAs.
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Affiliation(s)
- Gemma L Thompson
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK.,National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK
| | - David Kavanagh
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK.,National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK
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Ballermann BJ, Nyström J, Haraldsson B. The Glomerular Endothelium Restricts Albumin Filtration. Front Med (Lausanne) 2021; 8:766689. [PMID: 34912827 PMCID: PMC8667033 DOI: 10.3389/fmed.2021.766689] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 11/05/2021] [Indexed: 12/29/2022] Open
Abstract
Inflammatory activation and/or dysfunction of the glomerular endothelium triggers proteinuria in many systemic and localized vascular disorders. Among them are the thrombotic microangiopathies, many forms of glomerulonephritis, and acute inflammatory episodes like sepsis and COVID-19 illness. Another example is the chronic endothelial dysfunction that develops in cardiovascular disease and in metabolic disorders like diabetes. While the glomerular endothelium is a porous sieve that filters prodigious amounts of water and small solutes, it also bars the bulk of albumin and large plasma proteins from passing into the glomerular filtrate. This endothelial barrier function is ascribed predominantly to the endothelial glycocalyx with its endothelial surface layer, that together form a relatively thick, mucinous coat composed of glycosaminoglycans, proteoglycans, glycolipids, sialomucins and other glycoproteins, as well as secreted and circulating proteins. The glycocalyx/endothelial surface layer not only covers the glomerular endothelium; it extends into the endothelial fenestrae. Some glycocalyx components span or are attached to the apical endothelial cell plasma membrane and form the formal glycocalyx. Other components, including small proteoglycans and circulating proteins like albumin and orosomucoid, form the endothelial surface layer and are bound to the glycocalyx due to weak intermolecular interactions. Indeed, bound plasma albumin is a major constituent of the endothelial surface layer and contributes to its barrier function. A role for glomerular endothelial cells in the barrier of the glomerular capillary wall to protein filtration has been demonstrated by many elegant studies. However, it can only be fully understood in the context of other components, including the glomerular basement membrane, the podocytes and reabsorption of proteins by tubule epithelial cells. Discovery of the precise mechanisms that lead to glycocalyx/endothelial surface layer disruption within glomerular capillaries will hopefully lead to pharmacological interventions that specifically target this important structure.
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Affiliation(s)
| | - Jenny Nyström
- Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Börje Haraldsson
- Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
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