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Kostovska I, Trajkovska KT, Topuzovska S, Cekovska S, Labudovic D, Kostovski O, Spasovski G. Nephrinuria and podocytopathies. Adv Clin Chem 2022; 108:1-36. [PMID: 35659057 DOI: 10.1016/bs.acc.2021.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The discovery of nephrin in 1998 has launched a new era in glomerular diseases research, emphasizing its crucial role in the structure and function of the glomerular filtration barrier. In the past 20 years, substantial advances have been made in understanding podocyte structure and function as well as the discovery of several podocyte-related proteins including nephrin. The glomerular filtration barrier is comprised of podocytes, the glomerular basement membrane and endothelial cells. Podocytes, with their specialized slit diaphragm, form the essential backbone of the glomerular filtration barrier. Nephrin is a crucial structural and functional feature of the slit diaphragm that prevents plasma protein, blood cell and macromolecule leakage into the urine. Podocyte damage results in nephrin release. Podocytopathies are kidney diseases in which podocyte damage drives proteinuria, i.e., nephrotic syndrome. Many kidney diseases involve podocytopathy including congenital nephrotic syndrome of Finnish type, diffuse mesangial sclerosis, minimal change disease, focal segmental glomerulosclerosis, collapsing glomerulonephropathy, diabetic nephropathy, lupus nephropathy, hypertensive nephropathy and preeclampsia. Recently, urinary nephrin measurement has become important in the early detection of podocytopathies. In this chapter, we elaborate the main structural and functional features of nephrin as a podocyte-specific protein, pathomechanisms of podocytopathies which result in nephrinuria, highlight the most commonly used methods for detecting urinary nephrin and investigate the diagnostic, prognostic and potential therapeutic relevance of urinary nephrin in primary and secondary proteinuric kidney diseases.
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Affiliation(s)
- Irena Kostovska
- Department of Medical and Experimental Biochemistry, Faculty of Medicine, Ss. Cyril and Methodius University, Skopje, North Macedonia.
| | - Katerina Tosheska Trajkovska
- Department of Medical and Experimental Biochemistry, Faculty of Medicine, Ss. Cyril and Methodius University, Skopje, North Macedonia
| | - Sonja Topuzovska
- Department of Medical and Experimental Biochemistry, Faculty of Medicine, Ss. Cyril and Methodius University, Skopje, North Macedonia
| | - Svetlana Cekovska
- Department of Medical and Experimental Biochemistry, Faculty of Medicine, Ss. Cyril and Methodius University, Skopje, North Macedonia
| | - Danica Labudovic
- Department of Medical and Experimental Biochemistry, Faculty of Medicine, Ss. Cyril and Methodius University, Skopje, North Macedonia
| | - Ognen Kostovski
- University Clinic of Abdominal Surgery, Faculty of Medicine, Ss. Cyril and Methodius University, Skopje, North Macedonia
| | - Goce Spasovski
- University Clinic of Nephrology, Faculty of Medicine, Ss. Cyril and Methodius University, Skopje, North Macedonia
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Mulukala SKN, Kambhampati V, Qadri AH, Pasupulati AK. Evolutionary conservation of intrinsically unstructured regions in slit-diaphragm proteins. PLoS One 2021; 16:e0254917. [PMID: 34288970 PMCID: PMC8294545 DOI: 10.1371/journal.pone.0254917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 07/06/2021] [Indexed: 01/19/2023] Open
Abstract
Vertebrate kidneys contribute to homeostasis by regulating electrolyte, acid-base balance, removing toxic metabolites from blood, and preventing protein loss into the urine. Glomerular podocytes constitute the blood-urine barrier, and podocyte slit-diaphragm (SD), a modified tight junction, contributes to the glomerular permselectivity. Nephrin, KIRREL1, podocin, CD2AP, and TRPC6 are crucial members of the SD that interact with each other and contribute to the SD's structural and functional integrity. This study analyzed the distribution of these five essential SD proteins across the organisms for which the genome sequence is available. We found a diverse distribution of nephrin and KIRREL1 ranging from nematodes to higher vertebrates, whereas podocin, CD2AP, and TRPC6 are restricted to the vertebrates. Among invertebrates, nephrin and its orthologs consist of more immunoglobulin-3 domains, whereas in the vertebrates, CD80-like C2-set domains are predominant. In the case of KIRREL1 and its orthologs, more Ig domains were observed in invertebrates than vertebrates. Src Homology-3 (SH3) domain of CD2AP and SPFH domain of podocin are highly conserved among vertebrates. TRPC6 and its orthologs had conserved ankyrin repeats, TRP, and ion transport domains, except Chondrichthyes and Echinodermata, which do not possess the ankyrin repeats. Intrinsically unstructured regions (IURs) are conserved across the SD orthologs, suggesting IURs importance in the protein complexes that constitute the slit-diaphragm. For the first time, a study reports the evolutionary insights of vertebrate SD proteins and their invertebrate orthologs.
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Affiliation(s)
- Sandeep K N Mulukala
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Vaishnavi Kambhampati
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Abrar H Qadri
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Anil K Pasupulati
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
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Abstract
The glycome describes the complete repertoire of glycoconjugates composed of carbohydrate chains, or glycans, that are covalently linked to lipid or protein molecules. Glycoconjugates are formed through a process called glycosylation and can differ in their glycan sequences, the connections between them and their length. Glycoconjugate synthesis is a dynamic process that depends on the local milieu of enzymes, sugar precursors and organelle structures as well as the cell types involved and cellular signals. Studies of rare genetic disorders that affect glycosylation first highlighted the biological importance of the glycome, and technological advances have improved our understanding of its heterogeneity and complexity. Researchers can now routinely assess how the secreted and cell-surface glycomes reflect overall cellular status in health and disease. In fact, changes in glycosylation can modulate inflammatory responses, enable viral immune escape, promote cancer cell metastasis or regulate apoptosis; the composition of the glycome also affects kidney function in health and disease. New insights into the structure and function of the glycome can now be applied to therapy development and could improve our ability to fine-tune immunological responses and inflammation, optimize the performance of therapeutic antibodies and boost immune responses to cancer. These examples illustrate the potential of the emerging field of 'glycomedicine'.
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Affiliation(s)
- Colin Reily
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Tyler J Stewart
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Matthew B Renfrow
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Jan Novak
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA.
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Yun BH, Lee SM, Cho HY, Kim JY, Son GH, Kim YH, Park YW, Lim BJ, Kwon JY. Expression of nephrin in the human placenta and fetal membranes. Mol Med Rep 2015; 12:5116-20. [PMID: 26151763 DOI: 10.3892/mmr.2015.4044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 11/20/2014] [Indexed: 11/05/2022] Open
Abstract
Nephrin is the signature molecule in the podocyte of the glomerulus that forms the renal slit diaphragm, the main functional unit of the glomerulus. The present study focused on the expression of nephrin in the human placenta, which may also have a role in filtration and the maintenance of homeostasis in the kidneys. A total of nine placentas from normal healthy pregnant females at full term were investigated. Reverse transcription-quantitative polymerase chain reaction, western blotting and immunofluorescence were performed. The expression of nephrin mRNA was relatively increased in the chorion compared with that in the villi and the amnion. The nephrin gene was detected in the villous cytotrophoblast cells and the endothelium of the intravillous vessels. It was also present in the chorionic and amniotic membranous lining, with its distribution being particularly dense in the amniocytes. The identification of nephrin in the human placenta, particularly at the maternal‑fetal interface, provides a novel insight into the molecular basis of the selective permeability of the placental barrier, which requires further elucidation.
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Affiliation(s)
- Bo Hyon Yun
- Division of Maternal‑Fetal Medicine, Department of Obstetrics and Gynecology, Institute of Women's Life Medical Science, Yonsei University College of Medicine, Seoul 120‑752, Republic of Korea
| | - Seung Mi Lee
- Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul 110‑799, Republic of Korea
| | - Hee Young Cho
- Division of Maternal‑Fetal Medicine, Department of Obstetrics and Gynecology, Institute of Women's Life Medical Science, Yonsei University College of Medicine, Seoul 120‑752, Republic of Korea
| | - Ji Young Kim
- Department of Dermatology, Yonsei University College of Medicine, Seoul 120‑752, Republic of Korea
| | - Ga Hyun Son
- Department of Obstetrics and Gynecology, Kangnam Sacred Heart Hospital, Hallym University Medical Center, Seoul 150‑719, Republic of Korea
| | - Young Han Kim
- Division of Maternal‑Fetal Medicine, Department of Obstetrics and Gynecology, Institute of Women's Life Medical Science, Yonsei University College of Medicine, Seoul 120‑752, Republic of Korea
| | - Yong Won Park
- Division of Maternal‑Fetal Medicine, Department of Obstetrics and Gynecology, Institute of Women's Life Medical Science, Yonsei University College of Medicine, Seoul 120‑752, Republic of Korea
| | - Beom Jin Lim
- Department of Pathology, Gangnam Severance Hospital, Yonsei University Health System, Seoul 135‑720, Republic of Korea
| | - Ja Young Kwon
- Division of Maternal‑Fetal Medicine, Department of Obstetrics and Gynecology, Institute of Women's Life Medical Science, Yonsei University College of Medicine, Seoul 120‑752, Republic of Korea
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Liu Y, Liang W, Yang Y, Pan Y, Yang Q, Chen X, Singhal PC, Ding G. IQGAP1 regulates actin cytoskeleton organization in podocytes through interaction with nephrin. Cell Signal 2015; 27:867-77. [PMID: 25652011 DOI: 10.1016/j.cellsig.2015.01.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 01/27/2015] [Indexed: 10/24/2022]
Abstract
Increasing data has shown that the cytoskeletal reorganization of podocytes is involved in the onset of proteinuria and the progression of glomerular disease. Nephrin behaves as a signal sensor of the slit diaphragm to transmit cytoskeletal signals to maintain the unique structure of podocytes. However, the nephrin signaling cascade deserves further study. IQGAP1 is a scaffolding protein with the ability to regulate cytoskeletal organization. It is hypothesized that IQGAP1 contributes to actin reorganization in podocytes through interaction with nephrin. IQGAP1 expression and IQGAP1-nephrin colocalization in glomeruli were progressively decreased and then gradually recovered in line with the development of foot process fusion and proteinuria in puromycin aminonucleoside-injected rats. In cultured human podocytes, puromycin aminonucleoside-induced disruption of F-actin and disorders of migration and spreading were aggravated by IQGAP1 siRNA, and these effects were partially restored by a wild-type IQGAP1 plasmid. Furthermore, the cytoskeletal disorganization stimulated by cytochalasin D in COS7 cells was recovered by cotransfection with wild-type IQGAP1 and nephrin plasmids but was not recovered either by single transfection of the wild-type IQGAP1 plasmid or by cotransfection of mutant IQGAP1 [△1443(S→A)] and wild-type nephrin plasmids. Co-immunoprecipitation analysis using lysates of COS7 cells overexpressing nephrin and each derivative-domain molecule of IQGAP1 demonstrated that the poly-proline binding domain and RasGAP domain in the carboxyl terminus of IQGAP1 are the target modules that interact with nephrin. Collectively, these findings showed that activated IQGAP1, as an intracellular partner of nephrin, is involved in actin cytoskeleton organization and functional regulation of podocytes.
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Affiliation(s)
- Yipeng Liu
- Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, China; Department of Nephrology, Qianfoshan Hospital, Shandong University, Jinan, China
| | - Wei Liang
- Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yingjie Yang
- Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yangbin Pan
- Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Qian Yang
- Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Xinghua Chen
- Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Pravin C Singhal
- Renal Molecular Research Laboratory, Feinstein Institute for Medical Research, Hofstra North Shore LIJ Medical School, Great Neck, NY, USA
| | - Guohua Ding
- Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, China.
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