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Liu PJ, Sayeeda K, Zhuang C, Krendel M. Roles of myosin 1e and the actin cytoskeleton in kidney functions and familial kidney disease. Cytoskeleton (Hoboken) 2024. [PMID: 38708443 DOI: 10.1002/cm.21861] [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: 12/28/2023] [Revised: 03/21/2024] [Accepted: 04/04/2024] [Indexed: 05/07/2024]
Abstract
Mammalian kidneys are responsible for removing metabolic waste and maintaining fluid and electrolyte homeostasis via selective filtration. One of the proteins closely linked to selective renal filtration is myosin 1e (Myo1e), an actin-dependent molecular motor found in the specialized kidney epithelial cells involved in the assembly and maintenance of the renal filter. Point mutations in the gene encoding Myo1e, MYO1E, have been linked to familial kidney disease, and Myo1e knockout in mice leads to the disruption of selective filtration. In this review, we discuss the role of the actin cytoskeleton in renal filtration, the known and hypothesized functions of Myo1e, and the possible explanations for the impact of MYO1E mutations on renal function.
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Affiliation(s)
- Pei-Ju Liu
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Kazi Sayeeda
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Cindy Zhuang
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Mira Krendel
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
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2
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Xia X, Li S, Wang Z, Ye S, Fan Y, Peng W, Chen W, Huang F, Tang R, Chen W. Glomerular Exostosin-Positivity is Associated With Disease Activity and Outcomes in Patients With Membranous Lupus Nephritis. Kidney Int Rep 2024; 9:1040-1046. [PMID: 38765564 PMCID: PMC11101748 DOI: 10.1016/j.ekir.2024.01.008] [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: 11/13/2023] [Revised: 12/11/2023] [Accepted: 01/02/2024] [Indexed: 05/22/2024] Open
Abstract
Introduction The relationship of exostosin 1 and exostosin 2 (EXT1/EXT2) expression and outcomes in membranous lupus nephritis (MLN) was controversial. Methods EXT1/EXT2 was performed by immunohistochemistry (IHC) in 283 consecutive patients with MLN. Clinicopathological characteristics and outcomes of EXT1/EXT2-positive patients were compared with EXT1/EXT2-negative patients. The primary end points were adverse renal events, including death, dialysis, and renal transplantation. Results Of the patients with MLN, 29.3% were positive for EXT1/EXT2. The prevalence of EXT1/2-positive MLN was significantly higher in pure class V MLN than those for mixed class V MLN (44.2% vs. 19.4%, P < 0.001). For EXT1/EXT2-positive patients, the median time between onset of lupus and renal biopsy, and lupus nephritis and renal biopsy is shorter (6 [interquartile range, IQR: 2-25] months vs. 12 [IQR: 3-49] months, P = 0.008 and 3 [IQR: 2-18] months vs. 6 [IQR: 2-23] months, P = 0.039) and they had significantly lower systemic lupus erythematosus Disease Activity Index (SLEDAI) scores (P = 0.015) and lower serum creatinine levels (P < 0.001), higher hemoglobin (P = 0.006) as well as lower blood pressure. The EXT1/EXT2-positive patients had significantly fewer chronicity features (glomerulosclerosis, P < 0.001; interstitial fibrosis, P = 0.006; and tubular atrophy, P = 0.002) and fewer activity indicators (endocapillary hypercellularity, P = 0.012; cellular crescents, P = 0.007; and fibrocellular crescents, P < 0.001) on renal biopsy. After a median follow-up of 65 (28-126) months, EXT1/EXT2-positive patients were less likely to experience adverse renal events (2.4% vs. 16.0%, P = 0.001). Conclusion Compared with EXT1/EXT2-negative patients, the EXT1/EXT2-positive patients presented with lower disease activity and were less likely to experience adverse renal events in relationship with the chronicity index.
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Affiliation(s)
- Xi Xia
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-Sen University, People’s Republic of China
- NHC Key Laboratory of Clinical Nephrology (Sun Yat-Sen University) and Guangdong Provincial Key Laboratory of Nephrology, People’s Republic of China
| | - Suchun Li
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-Sen University, People’s Republic of China
- NHC Key Laboratory of Clinical Nephrology (Sun Yat-Sen University) and Guangdong Provincial Key Laboratory of Nephrology, People’s Republic of China
| | - Zhipeng Wang
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-Sen University, People’s Republic of China
- NHC Key Laboratory of Clinical Nephrology (Sun Yat-Sen University) and Guangdong Provincial Key Laboratory of Nephrology, People’s Republic of China
| | - Siyang Ye
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-Sen University, People’s Republic of China
- NHC Key Laboratory of Clinical Nephrology (Sun Yat-Sen University) and Guangdong Provincial Key Laboratory of Nephrology, People’s Republic of China
| | - Yuting Fan
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-Sen University, People’s Republic of China
- NHC Key Laboratory of Clinical Nephrology (Sun Yat-Sen University) and Guangdong Provincial Key Laboratory of Nephrology, People’s Republic of China
| | - Wenxing Peng
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-Sen University, People’s Republic of China
- NHC Key Laboratory of Clinical Nephrology (Sun Yat-Sen University) and Guangdong Provincial Key Laboratory of Nephrology, People’s Republic of China
| | - Wenfang Chen
- Department of Pathology, The First Affiliated Hospital of Sun Yat-Sen University, People’s Republic of China
| | - Fengxian Huang
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-Sen University, People’s Republic of China
- NHC Key Laboratory of Clinical Nephrology (Sun Yat-Sen University) and Guangdong Provincial Key Laboratory of Nephrology, People’s Republic of China
| | - Ruihan Tang
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-Sen University, People’s Republic of China
- NHC Key Laboratory of Clinical Nephrology (Sun Yat-Sen University) and Guangdong Provincial Key Laboratory of Nephrology, People’s Republic of China
| | - Wei Chen
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-Sen University, People’s Republic of China
- NHC Key Laboratory of Clinical Nephrology (Sun Yat-Sen University) and Guangdong Provincial Key Laboratory of Nephrology, People’s Republic of China
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Balbotkina EV, Karavashkina TA, Seliverstova EV, Kutina AV. Microalbuminuria in Rats Treated with D-Nitroarginine Methyl Ether. Bull Exp Biol Med 2024; 176:437-441. [PMID: 38491255 DOI: 10.1007/s10517-024-06042-x] [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: 05/30/2023] [Indexed: 03/18/2024]
Abstract
Microalbuminuria is an early symptom and prognostic marker of the progression of renal pathology. The analysis of the role of anionic components of the renal glomeruli in the albumin retention and the development of a model of minimal changes in the glomerular filter leading to the appearance of microalbuminuria are relevant. The effect of organic cations D-arginine methyl esters (D-AME) and D-nitroarginine (D-NAME) on the excretion of albumin by the kidneys in rats was studied. D-AME had no effect on urinary albumin excretion in rats. D-NAME caused microalbuminuria, which persisted for more than a day and sharply increased after injection of vasopressin. The number of anionic sites labeled with polyethyleneimine decreased in the structures of the glomerular filter. D-NAME-induced microalbuminuria can later serve as a model for studying nephroprotective or damaging factors.
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Affiliation(s)
- E V Balbotkina
- I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - T A Karavashkina
- I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - E V Seliverstova
- I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - A V Kutina
- I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia.
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Smith DW, Azadi A, Lee CJ, Gardiner BS. Spatial composition and turnover of the main molecules in the adult glomerular basement membrane. Tissue Barriers 2023; 11:2110798. [PMID: 35959954 PMCID: PMC10364650 DOI: 10.1080/21688370.2022.2110798] [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: 03/22/2022] [Revised: 07/31/2022] [Accepted: 08/03/2022] [Indexed: 10/15/2022] Open
Abstract
The glomerular basement membrane (GBM) is an important tissue structure in kidney function. It is the membrane through which filtrate and solutes must pass to reach the nephron tubules. This review focuses on the spatial location of the main extracellular matrix components of the GBM. It also attempts to explain this organization in terms of their synthesis, transport, and loss. The picture that emerges is that the collagen IV and laminin content of GBM are in a very slow dynamic disequilibrium, leading to GBM thickening with age, and in contrast, some heparan sulfate proteoglycans are in a dynamic equilibrium with a very rapid turnover (i.e. half-life measured in ~hours) and flow direction against the flow of filtrate. The highly rapid heparan sulfate turnover may serve several roles, including an unclogging mechanism for the GBM, compressive stiffness of the GBM fiber network, and/or enabling podocycte-endothelial crosstalk against the flow of filtrate.
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Affiliation(s)
- David W. Smith
- Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Azin Azadi
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, Western Australia, Australia
| | - Chang-Joon Lee
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, Western Australia, Australia
| | - Bruce S. Gardiner
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, Western Australia, Australia
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5
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Yu H, Song YY, Li XH. Early diabetic kidney disease: Focus on the glycocalyx. World J Diabetes 2023; 14:460-480. [PMID: 37273258 PMCID: PMC10236994 DOI: 10.4239/wjd.v14.i5.460] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 03/10/2023] [Accepted: 04/12/2023] [Indexed: 05/15/2023] Open
Abstract
The incidence of diabetic kidney disease (DKD) is sharply increasing worldwide. Microalbuminuria is the primary clinical marker used to identify DKD, and its initiating step in diabetes is glomerular endothelial cell dysfunction, particularly glycocalyx impairment. The glycocalyx found on the surface of glomerular endothelial cells, is a dynamic hydrated layer structure composed of pro-teoglycans, glycoproteins, and some adsorbed soluble components. It reinforces the negative charge barrier, transduces the shear stress, and mediates the interaction of blood corpuscles and podocytes with endothelial cells. In the high-glucose environment of diabetes, excessive reactive oxygen species and proinflammatory cytokines can damage the endothelial glycocalyx (EG) both directly and indirectly, which induces the production of microalbuminuria. Further research is required to elucidate the role of the podocyte glycocalyx, which may, together with endothelial cells, form a line of defense against albumin filtration. Interestingly, recent research has confirmed that the negative charge barrier function of the glycocalyx found in the glomerular basement membrane and its repulsion effect on albumin is limited. Therefore, to improve the early diagnosis and treatment of DKD, the potential mechanisms of EG degradation must be analyzed and more responsive and controllable targets must be explored. The content of this review will provide insights for future research.
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Affiliation(s)
- Hui Yu
- Department of Nephrology, Qilu Hospital of Shandong University, Jinan 250012, Shandong Province, China
| | - Yi-Yun Song
- Department of Nephrology, Qilu Hospital of Shandong University, Jinan 250012, Shandong Province, China
| | - Xian-Hua Li
- Department of Nephrology, Qilu Hospital of Shandong University, Jinan 250012, Shandong Province, China
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Comper WD, Vuchkova J, McCarthy KJ. New insights into proteinuria/albuminuria. Front Physiol 2022; 13:991756. [PMID: 36225307 PMCID: PMC9548894 DOI: 10.3389/fphys.2022.991756] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 08/29/2022] [Indexed: 11/13/2022] Open
Abstract
The fractional clearance of proteins as measured in healthy human subjects increases 10,000–100,000- fold when studied in nephrotic patients. This remarkable increase cannot be accounted for by extracellular biophysical mechanisms centered at the glomerular filtration barrier. Rather, it is the nephron and its combination of filtration and cellular uptake that can provide a plausible explanation of these fractional clearance changes. The nephron has two regions that critically determine the level proteinuria/albuminuria. Glomerular filtration of plasma proteins is primarily a size selective event that is basically unchanged in acquired and genetic kidney disease. The glomerular concepts of ‘charge selectivity’ and of ‘large pores’, previously used to explain proteinuria, are now recognized to be flawed and non-existent. Filtered proteins then encounter downstream two protein receptors of the Park and Maack type associated with the proximal tubular cell. The high capacity receptor is thought to retrieve the majority of filtered proteins and return them to the blood supply. Inhibition/saturation of this pathway in kidney disease may create the nephrotic condition and hypoproteinemia/hypoalbuminemia. Inhibitors of this pathway (possibly podocyte derived) are still to be identified. A relatively small proportion of the filtered protein is directed towards a high affinity, low capacity receptor that guides the protein to undergo lysosomal degradation. Proteinuria in normoproteinemic states is derived by inhibition of this pathway, such as in diabetes. The combination of glomerular sieving, and the degradation and retrieval pathways can quantitatively account for the changes in fractional clearance of proteins in the nephrotic condition. Finally, the general retrieval of filtered protein by the proximal tubular cell focuses on the teleological importance of this cell as this retrieval represents the third pillar of retrieval that this cell participates in (it also retrieves water and salt).
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Affiliation(s)
- Wayne D. Comper
- Salaqua Diagnostics Inc, New York, NY, United States
- *Correspondence: Wayne D. Comper,
| | | | - Kevin J. McCarthy
- Department of Cellular Biology and Anatomy, LSU Health Sciences Center, Shreveport, LA, United States
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7
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COUP-TFII in Kidneys, from Embryos to Sick Adults. Diagnostics (Basel) 2022; 12:diagnostics12051181. [PMID: 35626336 PMCID: PMC9139597 DOI: 10.3390/diagnostics12051181] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 05/02/2022] [Accepted: 05/06/2022] [Indexed: 11/16/2022] Open
Abstract
Chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII) is an orphan nuclear hormone receptor of unknown ligands. This molecule has two interesting features: (1) it is a developmental gene, and (2) it is a potential hormone receptor. Here, we describe the possible roles of COUP-TFII in the organogenesis of the kidneys and protection from adult renal diseases, primarily in mouse models. COUP-TFII is highly expressed in embryos, including primordial kidneys, and is essential for the formation of metanephric mesenchyme and the survival of renal precursor cells. Although the expression levels of COUP-TFII are low and its functions are unknown in healthy adults, it serves as a reno-protectant molecule against acute kidney injury. These are good examples of how developmental genes exhibit novel functions in the etiology of adult diseases. We also discuss the ongoing research on the roles of COUP-TFII in podocyte development and diabetic kidney disease. In addition, the identification of potential ligands suggests that COUP-TFII might be a novel therapeutic target for renal diseases in the future.
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8
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Khalil R, Boels MGS, van den Berg BM, Bruijn JA, Rabelink TJ, Hogendoorn PCW, Baelde HJ. Mutations in the heparan sulfate backbone elongating enzymes EXT1 and EXT2 have no major effect on endothelial glycocalyx and the glomerular filtration barrier. Mol Genet Genomics 2022; 297:397-405. [PMID: 35103870 PMCID: PMC8960589 DOI: 10.1007/s00438-022-01854-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 12/31/2021] [Indexed: 11/30/2022]
Abstract
In this study, the effect of heterozygous germline mutations in the heparan sulfate (HS) glycosaminoglycan chain co-polymerases EXT1 and EXT2 on glomerular barrier function and the endothelial glycocalyx in humans is investigated. Heparan sulfate (HS) glycosaminoglycans are deemed essential to the glomerular filtration barrier, including the glomerular endothelial glycocalyx. Animal studies have shown that loss of HS results in a thinner glycocalyx. Also, decreased glomerular HS expression is observed in various proteinuric renal diseases in humans. A case report of a patient with an EXT1 mutation indicated that this could result in a specific renal phenotype. This patient suffered from multiple osteochondromas, an autosomal dominant disease caused by mono-allelic germline mutations in the EXT1 or EXT2 gene. These studies imply that HS is indeed essential to the glomerular filtration barrier. However, loss of HS did not lead to proteinuria in various animal models. We demonstrate that multiple osteochondroma patients do not have more microalbuminuria or altered glycocalyx properties compared to age-matched controls (n = 19). A search for all Dutch patients registered with both osteochondroma and kidney biopsy (n = 39) showed that an EXT1 or EXT2 mutation does not necessarily lead to specific glomerular morphological phenotypic changes. In conclusion, this study shows that a heterozygous mutation in the HS backbone elongating enzymes EXT1 and EXT2 in humans does not result in (micro)albuminuria, a specific renal phenotype or changes to the endothelial glycocalyx, adding to the growing knowledge on the role of EXT1 and EXT2 genes in pathophysiology.
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Affiliation(s)
- Ramzi Khalil
- Department of Pathology, Leiden University Medical Center, L1Q, Room P0-107, P.O. Box 9600, 2300 RC, Leiden, The Netherlands
| | - Margien G S Boels
- The Einthoven Laboratory for Vascular and Regenerative Medicine, Department of Internal Medicine, Division of Nephrology, Leiden University Medical Center, Leiden, The Netherlands
| | - Bernard M van den Berg
- The Einthoven Laboratory for Vascular and Regenerative Medicine, Department of Internal Medicine, Division of Nephrology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jan A Bruijn
- Department of Pathology, Leiden University Medical Center, L1Q, Room P0-107, P.O. Box 9600, 2300 RC, Leiden, The Netherlands
| | - Ton J Rabelink
- The Einthoven Laboratory for Vascular and Regenerative Medicine, Department of Internal Medicine, Division of Nephrology, Leiden University Medical Center, Leiden, The Netherlands
| | - Pancras C W Hogendoorn
- Department of Pathology, Leiden University Medical Center, L1Q, Room P0-107, P.O. Box 9600, 2300 RC, Leiden, The Netherlands
| | - Hans J Baelde
- Department of Pathology, Leiden University Medical Center, L1Q, Room P0-107, P.O. Box 9600, 2300 RC, Leiden, The Netherlands.
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9
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Mashima R, Okuyama T, Ohira M. Physiology and Pathophysiology of Heparan Sulfate in Animal Models: Its Biosynthesis and Degradation. Int J Mol Sci 2022; 23:1963. [PMID: 35216081 PMCID: PMC8876164 DOI: 10.3390/ijms23041963] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/05/2022] [Accepted: 02/08/2022] [Indexed: 12/17/2022] Open
Abstract
Heparan sulfate (HS) is a type of glycosaminoglycan that plays a key role in a variety of biological functions in neurology, skeletal development, immunology, and tumor metastasis. Biosynthesis of HS is initiated by a link of xylose to Ser residue of HS proteoglycans, followed by the formation of a linker tetrasaccharide. Then, an extension reaction of HS disaccharide occurs through polymerization of many repetitive units consisting of iduronic acid and N-acetylglucosamine. Subsequently, several modification reactions take place to complete the maturation of HS. The sulfation positions of N-, 2-O-, 6-O-, and 3-O- are all mediated by specific enzymes that may have multiple isozymes. C5-epimerization is facilitated by the epimerase enzyme that converts glucuronic acid to iduronic acid. Once these enzymatic reactions have been completed, the desulfation reaction further modifies HS. Apart from HS biosynthesis, the degradation of HS is largely mediated by the lysosome, an intracellular organelle with acidic pH. Mucopolysaccharidosis is a genetic disorder characterized by an accumulation of glycosaminoglycans in the body associated with neuronal, skeletal, and visceral disorders. Genetically modified animal models have significantly contributed to the understanding of the in vivo role of these enzymes. Their role and potential link to diseases are also discussed.
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Affiliation(s)
- Ryuichi Mashima
- Department of Clinical Laboratory Medicine, National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535, Japan; (T.O.); (M.O.)
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10
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Purohit S, Piani F, Ordoñez FA, de Lucas-Collantes C, Bauer C, Cara-Fuentes G. Molecular Mechanisms of Proteinuria in Minimal Change Disease. Front Med (Lausanne) 2022; 8:761600. [PMID: 35004732 PMCID: PMC8733331 DOI: 10.3389/fmed.2021.761600] [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: 08/20/2021] [Accepted: 10/15/2021] [Indexed: 11/13/2022] Open
Abstract
Minimal change disease (MCD) is the most common type of idiopathic nephrotic syndrome in childhood and represents about 15% cases in adults. It is characterized by massive proteinuria, edema, hypoalbuminemia, and podocyte foot process effacement on electron microscopy. Clinical and experimental studies have shown an association between MCD and immune dysregulation. Given the lack of inflammatory changes or immunocomplex deposits in the kidney tissue, MCD has been traditionally thought to be mediated by an unknown circulating factor(s), probably released by T cells that directly target podocytes leading to podocyte ultrastructural changes and proteinuria. Not surprisingly, research efforts have focused on the role of T cells and podocytes in the disease process. Nevertheless, the pathogenesis of the disease remains a mystery. More recently, B cells have been postulated as an important player in the disease either by activating T cells or by releasing circulating autoantibodies against podocyte targets. There are also few reports of endothelial injury in MCD, but whether glomerular endothelial cells play a role in the disease remains unexplored. Genome-wide association studies are providing insights into the genetic susceptibility to develop the disease and found a link between MCD and certain human haplotype antigen variants. Altogether, these findings emphasize the complex interplay between the immune system, glomerular cells, and the genome, raising the possibility of distinct underlying triggers and/or mechanisms of proteinuria among patients with MCD. The heterogeneity of the disease and the lack of good animal models of MCD remain major obstacles in the understanding of MCD. In this study, we will review the most relevant candidate mediators and mechanisms of proteinuria involved in MCD and the current models of MCD-like injury.
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Affiliation(s)
- Shrey Purohit
- Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States.,Department of Pediatrics, Section of Pediatric Nephrology, Children's Hospital Colorado, Aurora, CO, United States
| | - Federica Piani
- Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States.,Department of Medicine and Surgery Sciences, Alma Mater Studiorum University of Bologna, Bologna, Italy
| | - Flor A Ordoñez
- Division of Pediatric Nephrology, Hospital Universitario Central de Asturias, Oviedo, Spain
| | | | - Colin Bauer
- Department of Pediatrics, Section of Pediatric Nephrology, Children's Hospital Colorado, Aurora, CO, United States
| | - Gabriel Cara-Fuentes
- Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States.,Department of Pediatrics, Section of Pediatric Nephrology, Children's Hospital Colorado, Aurora, CO, United States
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11
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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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12
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Jandl K, Mutgan AC, Eller K, Schaefer L, Kwapiszewska G. The basement membrane in the cross-roads between the lung and kidney. Matrix Biol 2021; 105:31-52. [PMID: 34839001 DOI: 10.1016/j.matbio.2021.11.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 11/05/2021] [Accepted: 11/18/2021] [Indexed: 12/23/2022]
Abstract
The basement membrane (BM) is a specialized layer of extracellular matrix components that plays a central role in maintaining lung and kidney functions. Although the composition of the BM is usually tissue specific, the lung and the kidney preferentially use similar BM components. Unsurprisingly, diseases with BM defects often have severe pulmonary or renal manifestations, sometimes both. Excessive remodeling of the BM, which is a hallmark of both inflammatory and fibrosing diseases in the lung and the kidney, can lead to the release of BM-derived matrikines, proteolytic fragments with distinct biological functions. These matrikines can then influence disease activity at the site of liberation. However, they are also released to the circulation, where they can directly affect the vascular endothelium or target other organs, leading to extrapulmonary or extrarenal manifestations. In this review, we will summarize the current knowledge of the composition and function of the BM and its matrikines in health and disease, both in the lung and in the kidney. By comparison, we will highlight, why the BM and its matrikines may be central in establishing a renal-pulmonary interaction axis.
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Affiliation(s)
- Katharina Jandl
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria; Otto Loewi Research Center, Department of Pharmacology, Medical University of Graz, Graz, Austria
| | - Ayse Ceren Mutgan
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria; Otto Loewi Research Center, Department of Physiology, Medical University of Graz, Graz, Austria
| | - Kathrin Eller
- Clinical Division of Nephrology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Liliana Schaefer
- Institute of Pharmacology and Toxicology, Goethe University, Frankfurt, Germany
| | - Grazyna Kwapiszewska
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria; Otto Loewi Research Center, Department of Physiology, Medical University of Graz, Graz, Austria; Institute for Lung Health (ILH), Giessen, Germany..
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13
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Liu W, Huang G, Rui H, Geng J, Hu H, Huang Y, Huo G, Liu B, Xu A. Course monitoring of membranous nephropathy: Both autoantibodies and podocytes require multidimensional attention. Autoimmun Rev 2021; 21:102976. [PMID: 34757091 DOI: 10.1016/j.autrev.2021.102976] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 10/18/2021] [Accepted: 10/24/2021] [Indexed: 01/15/2023]
Abstract
A variety of podocyte antigens have been identified in human membranous nephropathy (MN), which is divided into various antigen-dominated subtypes, confirming the concept that MN is the common pattern of glomerular injury in multiple autoimmune responses. The detection of autoantibodies has been widely used, which promoted the clinical practice of MN toward personalized precision medicine. However, given the potential risks of immunosuppressive therapy, more autoantibodies and biomarkers need to be identified to predict the prognosis and therapeutic response of MN more accurately. In this review, we attempted to summarize the autoantigens/autoantibodies and autoimmune mechanisms that can predict disease states based on the current understanding of MN pathogenesis, especially the podocyte injury manifestations. In conclusion, both the autoimmune response and podocyte injury require multidimensional attention in the disease course of MN.
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Affiliation(s)
- Wenbin Liu
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, China
| | - Guangrui Huang
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, China
| | - Hongliang Rui
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, China
| | - Jie Geng
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, China
| | - Haikun Hu
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, China
| | - Yujiao Huang
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, China
| | - Guiyang Huo
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, China
| | - Baoli Liu
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, China.
| | - Anlong Xu
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, China.
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14
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Immunopathological analysis of the expression of glomerular exostosin 1 and exostosin 2 in Japanese patients with lupus nephritis. Virchows Arch 2021; 479:997-1005. [PMID: 34302213 DOI: 10.1007/s00428-021-03164-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 06/22/2021] [Accepted: 07/17/2021] [Indexed: 10/20/2022]
Abstract
Exostosin 1 and exostosin 2 (EXT1/EXT2) on glomerular basement membrane (GBM) were recently reported as novel putative antigens in secondary membranous nephropathy with autoimmune disease. However, the clinical significance of glomerular EXT1/EXT2 remains elusive in patients with lupus nephritis (LN). The immunofluorescence staining pattern of glomerular EXT1/EXT2 is also undetermined in membranous LN (MLN) or proliferative LN (PLN). We cross-sectionally analyzed patients with MLN (pure class V, n = 11) and PLN (class III, IV, and mixed class III/IV + V, n = 22) who underwent renal biopsies between 2010 and 2020 at Showa University Hospital. Glomerular EXT1/EXT2 expressions were evaluated by immunofluorescence. T-helper (Th) cell-related serum inflammatory cytokines were measured using enzyme-linked immunosorbent assay. The positivity for both EXT1/EXT2 was higher in patients with MLN than PLN (90.9% vs 63.6%, P = 0.212). MLN showed global and bright granular EXT1/EXT2 expressions along GBM, while PLN showed segmental and moderate expressions on GBM. Additionally, glomerular EXT1/EXT2 positivity was not associated with the degree of proteinuria or renal function in MLN and PLN patients, but the levels of serum anti-dsDNA antibody and circulating immune complexes were lower in patients with EXT1/EXT2-positive MLN than EXT1/EXT2-negative PLN. Moreover, serum complement levels and IL-4/IFN-γ ratios were elevated in EXT1/EXT2-positive MLN than EXT1/EXT2-negative PLN. Collectively, immunofluorescence staining for glomerular EXT1/EXT2 had characteristic patterns between MLN and PLN. Glomerular EXT1/EXT2 expressions tended to be high in Th2-dominant MLN patients without severe hypocomplementemia and elevated autoantibodies. Thus, EXT1/EXT2 might be involved in the unique developmental mechanism of MLN.
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15
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Kikkawa Y, Hashimoto T, Takizawa K, Urae S, Masuda H, Matsunuma M, Yamada Y, Hamada K, Nomizu M, Liapis H, Hisano M, Akioka Y, Miura K, Hattori M, Miner JH, Harita Y. Laminin β2 variants associated with isolated nephropathy that impact matrix regulation. JCI Insight 2021; 6:145908. [PMID: 33749661 PMCID: PMC8026196 DOI: 10.1172/jci.insight.145908] [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: 11/10/2020] [Accepted: 02/10/2021] [Indexed: 11/17/2022] Open
Abstract
Mutations in LAMB2, encoding laminin β2, cause Pierson syndrome and occasionally milder nephropathy without extrarenal abnormalities. The most deleterious missense mutations that have been identified affect primarily the N-terminus of laminin β2. On the other hand, those associated with isolated nephropathy are distributed across the entire molecule, and variants in the β2 LEa-LF-LEb domains are exclusively found in cases with isolated nephropathy. Here we report the clinical features of mild isolated nephropathy associated with 3 LAMB2 variants in the LEa-LF-LEb domains (p.R469Q, p.G699R, and p.R1078C) and their biochemical characterization. Although Pierson syndrome missense mutations often inhibit laminin β2 secretion, the 3 recombinant variants were secreted as efficiently as WT. However, the β2 variants lost pH dependency for heparin binding, resulting in aberrant binding under physiologic conditions. This suggests that the binding of laminin β2 to negatively charged molecules is involved in glomerular basement membrane (GBM) permselectivity. Moreover, the excessive binding of the β2 variants to other laminins appears to lead to their increased deposition in the GBM. Laminin β2 also serves as a potentially novel cell-adhesive ligand for integrin α4β1. Our findings define biochemical functions of laminin β2 variants influencing glomerular filtration that may underlie the pathogenesis of isolated nephropathy caused by LAMB2 abnormalities.
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Affiliation(s)
- Yamato Kikkawa
- Department of Clinical Biochemistry, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Taeko Hashimoto
- Department of Pediatrics, Yamagata University School of Medicine, Yamagata, Japan.,Department of Pediatric Nephrology, School of Medicine, Tokyo Women's Medical University, Tokyo, Japan
| | - Keiichi Takizawa
- Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Seiya Urae
- Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Haruka Masuda
- Department of Clinical Biochemistry, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Masumi Matsunuma
- Department of Clinical Biochemistry, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Yuji Yamada
- Department of Clinical Biochemistry, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Keisuke Hamada
- Department of Clinical Biochemistry, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Motoyoshi Nomizu
- Department of Clinical Biochemistry, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Helen Liapis
- Department of Pathology and Immunology and Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Masataka Hisano
- Department of Nephrology, Chiba Children's Hospital, Chiba, Japan
| | - Yuko Akioka
- Department of Pediatric Nephrology, School of Medicine, Tokyo Women's Medical University, Tokyo, Japan.,Department of Pediatrics, Faculty of Medicine, Saitama Medical University, Saitama, Japan
| | - Kenichiro Miura
- Department of Pediatric Nephrology, School of Medicine, Tokyo Women's Medical University, Tokyo, Japan
| | - Motoshi Hattori
- Department of Pediatric Nephrology, School of Medicine, Tokyo Women's Medical University, Tokyo, Japan
| | - Jeffrey H Miner
- Division of Nephrology, Department of Medicine, and Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Yutaka Harita
- Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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16
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Desideri S, Onions KL, Baker SL, Gamez M, El Hegni E Hussien H, Russell A, Satchell SC, Foster RR. Endothelial glycocalyx restoration by growth factors in diabetic nephropathy. Biorheology 2020; 56:163-179. [PMID: 31156139 DOI: 10.3233/bir-180199] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The endothelial glycocalyx (eGlx) constitutes the first barrier to protein in all blood vessels. This is particularly noteworthy in the renal glomerulus, an ultrafiltration barrier. Leakage of protein, such as albumin, across glomerular capillaries results in albumin in the urine (albuminuria). This is a hall mark of kidney disease and can reflect loss of blood vessel integrity in microvascular beds elsewhere. We discuss evidence demonstrating that targeted damage to the glomerular eGlx results in increased glomerular albumin permeability. EGlx is lost in diabetes and experimental models demonstrate loss from glomerular endothelial cells. Vascular endothelial growth factor (VEGF)A is upregulated in early diabetes, which is associated with albuminuria. Treatment with paracrine growth factors such as VEGFC, VEGF165b and angiopoietin-1 can modify VEGFA signalling, rescue albumin permeability and restore glomerular eGlx in models of diabetes. Manipulation of VEGF receptor 2 signalling, or a common eGlx biosynthesis pathway by these growth factors, may protect and restore the eGlx layer. This would help to direct future therapeutics in diabetic nephropathy.
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Key Words
- Endothelial glycocalyx, diabetes, diabetic nephropathy, VEGF, VEGFC, VEGFA, VEGF165b, angiopoietin-1, vascular permeability, glomerulus, glomerular permeability
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Affiliation(s)
- Sara Desideri
- Bristol Renal, Bristol Heart Institute, Translational Health Sciences, Bristol Medical School, University of Bristol, UK
| | - Karen L Onions
- Bristol Renal, Bristol Heart Institute, Translational Health Sciences, Bristol Medical School, University of Bristol, UK
| | - Siân L Baker
- Bristol Renal, Bristol Heart Institute, Translational Health Sciences, Bristol Medical School, University of Bristol, UK
| | - Monica Gamez
- Bristol Renal, Bristol Heart Institute, Translational Health Sciences, Bristol Medical School, University of Bristol, UK
| | - Hesham El Hegni E Hussien
- Bristol Renal, Bristol Heart Institute, Translational Health Sciences, Bristol Medical School, University of Bristol, UK
| | - Amy Russell
- Bristol Renal, Bristol Heart Institute, Translational Health Sciences, Bristol Medical School, University of Bristol, UK
| | - Simon C Satchell
- Bristol Renal, Bristol Heart Institute, Translational Health Sciences, Bristol Medical School, University of Bristol, UK
| | - Rebecca R Foster
- Bristol Renal, Bristol Heart Institute, Translational Health Sciences, Bristol Medical School, University of Bristol, UK
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17
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Ronco P. Pathophysiology of the glomerulus: KI tells the story. Kidney Int 2020; 97:5-9. [PMID: 31901357 DOI: 10.1016/j.kint.2019.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 11/15/2019] [Indexed: 02/04/2023]
Affiliation(s)
- Pierre Ronco
- Sorbonne Université, Paris, France; Institut National de la Santé et de la Recherche Médicale (Inserm), Unité Mixte de Recherche S1155, Paris, France; Hôpital de jour - Néphrologie, Assistance Publique-Hôpitaux de Paris, Hôpital Tenon, Paris, France.
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18
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van der Vlag J, Buijsers B. Heparanase in Kidney Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1221:647-667. [PMID: 32274730 DOI: 10.1007/978-3-030-34521-1_26] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The primary filtration of blood occurs in the glomerulus in the kidney. Destruction of any of the layers of the glomerular filtration barrier might result in proteinuric disease. The glomerular endothelial cells and especially its covering layer, the glycocalyx, play a pivotal role in development of albuminuria. One of the main sulfated glycosaminoglycans in the glomerular endothelial glycocalyx is heparan sulfate. The endoglycosidase heparanase degrades heparan sulfate, thereby affecting glomerular barrier function, immune reactivity and inflammation. Increased expression of glomerular heparanase correlates with loss of glomerular heparan sulfate in many glomerular diseases. Most importantly, heparanase knockout in mice prevented the development of albuminuria after induction of experimental diabetic nephropathy and experimental glomerulonephritis. Therefore, heparanase could serve as a pharmacological target for glomerular diseases. Several factors that regulate heparanase expression and activity have been identified and compounds aiming to inhibit heparanase activity are currently explored.
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Affiliation(s)
- Johan van der Vlag
- Department of Nephrology (480), Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA, Nijmegen, The Netherlands.
| | - Baranca Buijsers
- Department of Nephrology (480), Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA, Nijmegen, The Netherlands
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19
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Khalil R, Lalai RA, Wiweger MI, Avramut CM, Koster AJ, Spaink HP, Bruijn JA, Hogendoorn PCW, Baelde HJ. Glomerular permeability is not affected by heparan sulfate glycosaminoglycan deficiency in zebrafish embryos. Am J Physiol Renal Physiol 2019; 317:F1211-F1216. [PMID: 31461353 DOI: 10.1152/ajprenal.00126.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Proteinuria develops when specific components in the glomerular filtration barrier have impaired function. Although the precise components involved in maintaining this barrier have not been fully identified, heparan sulfate proteoglycans are believed to play an essential role in maintaining glomerular filtration. Although in situ studies have shown that a loss of heparan sulfate glycosaminoglycans increases the permeability of the glomerular filtration barrier, recent studies using experimental models have shown that podocyte-specific deletion of heparan sulfate glycosaminoglycan assembly does not lead to proteinuria. However, tubular reabsorption of leaked proteins might have masked an increase in glomerular permeability in these models. Furthermore, not only podocytes but also glomerular endothelial cells are involved in heparan sulfate synthesis in the glomerular filtration barrier. Therefore, we investigated the effect of a global heparan sulfate glycosaminoglycan deficiency on glomerular permeability. We used a zebrafish embryo model carrying a homozygous germline mutation in the ext2 gene. Glomerular permeability was assessed with a quantitative dextran tracer injection method. In this model, we accounted for tubular reabsorption. Loss of anionic sites in the glomerular basement membrane was measured using polyethyleneimine staining. Although mutant animals had significantly fewer negatively charged areas in the glomerular basement membrane, glomerular permeability was unaffected. Moreover, heparan sulfate glycosaminoglycan-deficient embryos had morphologically intact podocyte foot processes. Glomerular filtration remains fully functional despite a global reduction of heparan sulfate.
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Affiliation(s)
- Ramzi Khalil
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | - Reshma A Lalai
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Cristina M Avramut
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Abraham J Koster
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Herman P Spaink
- Institute of Biology Leiden, Leiden University, Leiden, The Netherlands
| | - Jan A Bruijn
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Hans J Baelde
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
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20
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Sethi S, Madden BJ, Debiec H, Charlesworth MC, Gross L, Ravindran A, Hummel AM, Specks U, Fervenza FC, Ronco P. Exostosin 1/Exostosin 2-Associated Membranous Nephropathy. J Am Soc Nephrol 2019; 30:1123-1136. [PMID: 31061139 DOI: 10.1681/asn.2018080852] [Citation(s) in RCA: 178] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 03/24/2019] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND In membranous nephropathy (MN), which is characterized by deposition of immune complexes along the glomerular basement membrane (GBM), phospholipase A2 receptor (PLA2R) and thrombospondin type 1 domain-containing 7A are target antigens in approximately 70% and 1%-5% of cases of primary MN, respectively. In other cases of primary MN and in secondary MN, the target antigens are unknown. METHODS We studied 224 cases of biopsy-proven PLA2R-negative MN and 102 controls (including 47 cases of PLA2R-associated MN) in pilot and discovery cohorts. We also evaluated 48 cases of PLA2R-negative presumed primary MN and lupus MN in a validation cohort. We used laser microdissection and mass spectrometry to identify new antigens, which were localized by immunohistochemistry. RESULTS Mass spectrometry detected exostosin 1 (EXT1) and exostosin 2 (EXT2) in 21 cases of PLA2R-negative MN, but not in PLA2R-associated MN and control cases. Immunohistochemistry staining revealed bright granular GBM staining for EXT1 and EXT2. Clinical and biopsy findings showed features of autoimmune disease, including lupus, in 80.7% of the 26 EXT1/EXT2-associated MN cases we identified. In the validation cohort, we confirmed that EXT1/EXT2 staining was detected in pure class 5 lupus nephritis (eight of 18 patients) and in presumed primary MN associated with signs of autoimmunity (three of 16 patients); only one of the 14 cases of mixed class 5 and 3/4 lupus nephritis was positive for EXT1/EXT2. Tests in seven patients with EXT1/EXT2-associated MN found no circulating anti-exostosin antibodies. CONCLUSIONS A subset of MN is associated with accumulation of EXT1 and EXT2 in the GBM. Autoimmune disease is common in this group of patients.
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Affiliation(s)
| | | | - Hanna Debiec
- Sorbonne Université, Université Pierre et Marie Curie Paris 06, and Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche S1155, Paris, France; and
| | | | | | | | | | - Ulrich Specks
- Divisions of Pulmonary and Critical Care Medicine and
| | | | - Pierre Ronco
- Sorbonne Université, Université Pierre et Marie Curie Paris 06, and Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche S1155, Paris, France; and.,Department of Nephrology and Dialysis, Assistance Publique-Hôpitaux de Paris, Tenon Hospital, Paris, France
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21
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Voinova M, Repin N, Sokol E, Tkachuk B, Gorelik L. Physical Processes in Polymeric Filters Used for Dialysis. Polymers (Basel) 2019; 11:E389. [PMID: 30960373 PMCID: PMC6473866 DOI: 10.3390/polym11030389] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 02/06/2019] [Accepted: 02/12/2019] [Indexed: 01/03/2023] Open
Abstract
The key physical processes in polymeric filters used for the blood purification include transport across the capillary wall and the interaction of blood cells with the polymer membrane surface. Theoretical modeling of membrane transport is an important tool which provides researchers with a quantification of the complex phenomena involved in dialysis. In the paper, we present a dense review of the most successful theoretical approaches to the description of transport across the polymeric membrane wall as well as the cell⁻polymer surface interaction, and refer to the corresponding experimental methods while studying these phenomena in dialyzing filters.
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Affiliation(s)
- Marina Voinova
- Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden.
- Department of Industrial and Biomedical Electronics, Kharkiv Polytechnical Institute, National Technical University, 61002 Kharkov, Ukraine.
| | - Nikolay Repin
- Department of Cryomorphology, Institute for Problems of Cryobiology and Cryomedicine, 61015 Kharkov, Ukraine.
| | - Evgen Sokol
- Department of Industrial and Biomedical Electronics, Kharkiv Polytechnical Institute, National Technical University, 61002 Kharkov, Ukraine.
| | - Bogdan Tkachuk
- Department of Hemodialysis, Municipal Noncommercial Enterprise of Kharkiv Regional Council "Regional Medical Clinical Center of Urology and Nephrology n.a. V.I. Shapoval", 61037 Kharkov, Ukraine.
| | - Leonid Gorelik
- Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden.
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22
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Ferreras L, Moles A, Situmorang GR, El Masri R, Wilson IL, Cooke K, Thompson E, Kusche-Gullberg M, Vivès RR, Sheerin NS, Ali S. Heparan sulfate in chronic kidney diseases: Exploring the role of 3-O-sulfation. Biochim Biophys Acta Gen Subj 2019; 1863:839-848. [PMID: 30794825 DOI: 10.1016/j.bbagen.2019.02.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 02/07/2019] [Accepted: 02/16/2019] [Indexed: 01/03/2023]
Abstract
One of the main feature of chronic kidney disease is the development of renal fibrosis. Heparan Sulfate (HS) is involved in disease development by modifying the function of growth factors and cytokines and creating chemokine gradients. In this context, we aimed to understand the function of HS sulfation in renal fibrosis. Using a mouse model of renal fibrosis, we found that total HS 2-O-sulfation was increased in damaged kidneys, whilst, tubular staining of HS 3-O-sulfation was decreased. The expression of HS modifying enzymes significantly correlated with the development of fibrosis with HS3ST1 demonstrating the strongest correlation. The pro-fibrotic factors TGFβ1 and TGFβ2/IL1β significantly downregulated HS3ST1 expression in both renal epithelial cells and renal fibroblasts. To determine the implication of HS3ST1 in growth factor binding and signalling, we generated an in vitro model of renal epithelial cells overexpressing HS3ST1 (HKC8-HS3ST1). Heparin Binding EGF like growth factor (HB-EGF) induced rapid, transient STAT3 phosphorylation in control HKC8 cells. In contrast, a prolonged response was demonstrated in HKC8-HS3ST1 cells. Finally, we showed that both HS 3-O-sulfation and HB-EGF tubular staining were decreased with the development of fibrosis. Taken together, these data suggest that HS 3-O-sulfation is modified in fibrosis and highlight HS3ST1 as an attractive biomarker of fibrosis progression with a potential role in HB-EGF signalling.
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Affiliation(s)
- Laura Ferreras
- Institute of Cellular Medicine, Faculty of Medical Sciences, Newcastle University, NE2 4HH, UK
| | - Anna Moles
- Institute of Cellular Medicine, Faculty of Medical Sciences, Newcastle University, NE2 4HH, UK
| | - Gerhard R Situmorang
- Institute of Cellular Medicine, Faculty of Medical Sciences, Newcastle University, NE2 4HH, UK
| | - Rana El Masri
- Univ. Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
| | - Imogen L Wilson
- Institute of Cellular Medicine, Faculty of Medical Sciences, Newcastle University, NE2 4HH, UK
| | - Katie Cooke
- Institute of Cellular Medicine, Faculty of Medical Sciences, Newcastle University, NE2 4HH, UK
| | - Emily Thompson
- Institute of Cellular Medicine, Faculty of Medical Sciences, Newcastle University, NE2 4HH, UK
| | - Marion Kusche-Gullberg
- University of Bergen, Department of Biomedicine, Jonas Lies vei 91, N-5009 Bergen, Norway
| | | | - Neil S Sheerin
- Institute of Cellular Medicine, Faculty of Medical Sciences, Newcastle University, NE2 4HH, UK; Newcastle upon Tyne Hospitals, NHS Foundation Trust, NIHR Newcastle Biomedical Research Centre, United Kingdom
| | - Simi Ali
- Institute of Cellular Medicine, Faculty of Medical Sciences, Newcastle University, NE2 4HH, UK.
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23
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Aoki S, Saito-Hakoda A, Yoshikawa T, Shimizu K, Kisu K, Suzuki S, Takagi K, Mizumoto S, Yamada S, van Kuppevelt TH, Yokoyama A, Matsusaka T, Sato H, Ito S, Sugawara A. The reduction of heparan sulphate in the glomerular basement membrane does not augment urinary albumin excretion. Nephrol Dial Transplant 2018; 33:26-33. [PMID: 28992095 DOI: 10.1093/ndt/gfx218] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Accepted: 04/23/2017] [Indexed: 01/12/2023] Open
Abstract
Background Heparan sulphate proteoglycan (HSPG) is present in the glomerular basement membrane (GBM) and is thought to play a major role in the glomerular charge barrier. Reductions and structural alterations of HSPG are observed in different types of kidney diseases accompanied by proteinuria. However, their causal relations remain unknown. Methods We generated podocyte-specific exostosin-like 3 gene (Extl3) knockout mice (Extl3KO) using a Cre-loxP recombination approach. A reduction of HSPG was expected in the GBM of these mice, because EXTL3 is involved in its synthesis. Mice were separated into three groups, according to the loads on the glomeruli: a high-protein diet group, a high-protein and high-sodium diet group and a hyperglycaemic group induced by streptozotocin treatment in addition to maintenance on a high-protein and high-sodium diet. The urinary albumin:creatinine ratio was measured at 7, 11, 15 and 19 weeks of age. Renal histology was also investigated. Results Podocyte-specific expression of Cre recombinase was detected by immunohistochemistry. Moreover, immunofluorescent staining demonstrated a significant reduction of HSPG in the GBM. Electron microscopy showed irregularities in the GBM and effacement of the foot processes in Extl3KO. The values of the urinary albumin:creatinine ratio were within the range of microalbuminuria in all groups and did not significantly differ between the control mice and Extl3KO. Conclusions The reduction of HSPG in the GBM did not augment urinary albumin excretion. HSPG's anionic charge appears to contribute little to the glomerular charge barrier.
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Affiliation(s)
- Satoshi Aoki
- Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Akiko Saito-Hakoda
- Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Takeo Yoshikawa
- Department of Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Kyoko Shimizu
- Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Kiyomi Kisu
- Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Susumu Suzuki
- Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Kiyoshi Takagi
- Department of Pathology and Histotechnology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Shuji Mizumoto
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijyo University, Nagoya, Aichi, Japan
| | - Shuhei Yamada
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijyo University, Nagoya, Aichi, Japan
| | - Toin H van Kuppevelt
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Atsushi Yokoyama
- Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Taiji Matsusaka
- Department of Molecular Life Sciences, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Hiroshi Sato
- Department of Clinical Pharmacology and Therapeutics, Tohoku University Graduate School of Pharmaceutical Sciences, Sendai, Miyagi, Japan
| | - Sadayoshi Ito
- Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Akira Sugawara
- Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
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Megalin/cubilin has a minor role in the proximal tubular cell uptake of filtered albumin. Kidney Int 2018; 93:1014. [PMID: 29571435 DOI: 10.1016/j.kint.2017.12.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 12/21/2017] [Indexed: 11/22/2022]
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Mundy C, Yang E, Takano H, Billings PC, Pacifici M. Heparan sulfate antagonism alters bone morphogenetic protein signaling and receptor dynamics, suggesting a mechanism in hereditary multiple exostoses. J Biol Chem 2018; 293:7703-7716. [PMID: 29622677 DOI: 10.1074/jbc.ra117.000264] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 03/23/2018] [Indexed: 11/06/2022] Open
Abstract
Hereditary multiple exostoses (HME) is a pediatric disorder caused by heparan sulfate (HS) deficiency and is characterized by growth plate-associated osteochondromas. Previously, we found that osteochondroma formation in mouse models is preceded by ectopic bone morphogenetic protein (BMP) signaling in the perichondrium, but the mechanistic relationships between BMP signaling and HS deficiency remain unclear. Therefore, we used an HS antagonist (surfen) to investigate the effects of this HS interference on BMP signaling, ligand availability, cell-surface BMP receptor (BMPR) dynamics, and BMPR interactions in Ad-293 and C3H/10T1/2 cells. As observed previously, the HS interference rapidly increased phosphorylated SMAD family member 1/5/8 levels. FACS analysis and immunoblots revealed that the cells possessed appreciable levels of endogenous cell-surface BMP2/4 that were unaffected by the HS antagonist, suggesting that BMP2/4 proteins remained surface-bound but became engaged in BMPR interactions and SMAD signaling. Indeed, surface mobility of SNAP-tagged BMPRII, measured by fluorescence recovery after photobleaching (FRAP), was modulated during the drug treatment. This suggested that the receptors had transitioned to lipid rafts acting as signaling centers, confirmed for BMPRII via ultracentrifugation to separate membrane subdomains. In situ proximity ligation assays disclosed that the HS interference rapidly stimulates BMPRI-BMPRII interactions, measured by oligonucleotide-driven amplification signals. Our in vitro studies reveal that cell-associated HS controls BMP ligand availability and BMPR dynamics, interactions, and signaling, and largely restrains these processes. We propose that HS deficiency in HME may lead to extensive local BMP signaling and altered BMPR dynamics, triggering excessive cellular responses and osteochondroma formation.
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Affiliation(s)
- Christina Mundy
- From the Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, and
| | - Evan Yang
- From the Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, and
| | - Hajime Takano
- the Department of Pediatrics, Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Paul C Billings
- From the Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, and
| | - Maurizio Pacifici
- From the Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, and
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Phan AQ, Pacifici M, Esko JD. Advances in the pathogenesis and possible treatments for multiple hereditary exostoses from the 2016 international MHE conference. Connect Tissue Res 2018; 59:85-98. [PMID: 29099240 PMCID: PMC7604901 DOI: 10.1080/03008207.2017.1394295] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Multiple hereditary exostoses (MHE) is an autosomal dominant disorder that affects about 1 in 50,000 children worldwide. MHE, also known as hereditary multiple exostoses (HME) or multiple osteochondromas (MO), is characterized by cartilage-capped outgrowths called osteochondromas that develop adjacent to the growth plates of skeletal elements in young patients. These benign tumors can affect growth plate function, leading to skeletal growth retardation, or deformations, and can encroach on nerves, tendons, muscles, and other surrounding tissues and cause motion impairment, chronic pain, and early onset osteoarthritis. In about 2-5% of patients, the osteochondromas can become malignant and life threatening. Current treatments consist of surgical removal of the most symptomatic tumors and correction of the major skeletal defects, but physical difficulties and chronic pain usually continue and patients may undergo multiple surgeries throughout life. Thus, there is an urgent need to find new treatments to prevent or reverse osteochondroma formation. The 2016 International MHE Research Conference was convened to provide a forum for the presentation of the most up-to-date and advanced clinical and basic science data and insights in MHE and related fields; to stimulate the forging of new perspectives, collaborations, and venues of research; and to publicize key scientific findings within the biomedical research community and share insights and relevant information with MHE patients and their families. This report provides a description, review, and assessment of all the exciting and promising studies presented at the Conference and delineates a general roadmap for future MHE research targets and goals.
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Affiliation(s)
- Anne Q. Phan
- Department of Cellular and Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, La Jolla, CA, USA
| | - Maurizio Pacifici
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Jeffrey D. Esko
- Department of Cellular and Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, La Jolla, CA, USA
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Pacifici M. The pathogenic roles of heparan sulfate deficiency in hereditary multiple exostoses. Matrix Biol 2017; 71-72:28-39. [PMID: 29277722 DOI: 10.1016/j.matbio.2017.12.011] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/19/2017] [Accepted: 12/19/2017] [Indexed: 12/20/2022]
Abstract
Heparan sulfate (HS) is an essential component of cell surface and matrix proteoglycans (HS-PGs) that include syndecans and perlecan. Because of their unique structural features, the HS chains are able to specifically interact with signaling proteins -including bone morphogenetic proteins (BMPs)- via their HS-binding domain, regulating protein availability, distribution and action on target cells. Hereditary Multiple Exostoses (HME) is a rare pediatric disorder linked to germline heterozygous loss-of-function mutations in EXT1 or EXT2 that encode Golgi-resident glycosyltransferases responsible for HS synthesis, resulting in a systemic HS deficiency. HME is characterized by cartilaginous/bony tumors -called osteochondromas or exostoses- that form within perichondrium in long bones, ribs and other elements. This review examines most recent studies in HME, framing them in the context of classic studies. New findings show that the spectrum of EXT mutations is larger than previously realized and the clinical complications of HME extend beyond the skeleton. Osteochondroma development requires a somatic "second hit" that would complement the germline EXT mutation to further decrease HS production and/levels at perichondrial sites of osteochondroma induction. Cellular studies have shown that the steep decreases in local HS levels: derange the normal homeostatic signaling pathways keeping perichondrium mesenchymal; cause excessive BMP signaling; and provoke ectopic chondrogenesis and osteochondroma formation. Data from HME mouse models have revealed that systemic treatment with a BMP signaling antagonist markedly reduces osteochondroma formation. In sum, recent studies have provided major new insights into the molecular and cellular pathogenesis of HME and the roles played by HS deficiency. These new insights have led to the first ever proof-of-principle demonstration that osteochondroma formation is a druggable process, paving the way toward the creation of a clinically-relevant treatment.
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Affiliation(s)
- Maurizio Pacifici
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States.
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Pathogenesis of proteinuria in idiopathic minimal change disease: molecular mechanisms. Pediatr Nephrol 2016; 31:2179-2189. [PMID: 27384691 DOI: 10.1007/s00467-016-3379-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 03/07/2016] [Accepted: 03/14/2016] [Indexed: 12/13/2022]
Abstract
Minimal change disease (MCD) is the most common type of nephrotic syndrome in children and adolescents. The pathogenesis of proteinuria in this condition is currently being reassessed. Following the Shalhoub hypothesis, most efforts have been placed on identifying the putative circulating factor, but recent advancement in podocyte biology has focused attention on the molecular changes at the glomerular capillary wall, which could explain the mechanism of proteinuria in MCD. This report critically reviews current knowledge on the different postulated mechanisms at the glomerular capillary wall level for increased permeability to plasma proteins in MCD. The report helps describe the rationale behind novel therapies and suggests future targeted therapies for MCD.
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Herman-Edelstein M, Chagnac A, Nevo Z, Skutelsky E, Evron Y, Hirsch Y, Ben-Dor L, Schwartz I, Schwartz D, Weinstein T. Angiotensin converting-enzyme inhibition restores glomerular glycosaminoglycans in rat puromycin nephrosis. ACTA ACUST UNITED AC 2016; 68:543-552. [DOI: 10.1016/j.etp.2016.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 08/03/2016] [Accepted: 08/22/2016] [Indexed: 11/25/2022]
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Cathepsin L is crucial for the development of early experimental diabetic nephropathy. Kidney Int 2016; 90:1012-1022. [DOI: 10.1016/j.kint.2016.06.035] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 06/22/2016] [Accepted: 06/30/2016] [Indexed: 11/20/2022]
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Borza DB. Glomerular basement membrane heparan sulfate in health and disease: A regulator of local complement activation. Matrix Biol 2016; 57-58:299-310. [PMID: 27609404 DOI: 10.1016/j.matbio.2016.09.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 08/30/2016] [Accepted: 09/01/2016] [Indexed: 12/26/2022]
Abstract
The glomerular basement membrane (GBM) is an essential component of the glomerular filtration barrier. Heparan sulfate proteoglycans such as agrin are major components of the GBM, along with α345(IV) collagen, laminin-521 and nidogen. A loss of GBM heparan sulfate chains is associated with proteinuria in several glomerular diseases and may contribute to the underlying pathology. As the major determinants of the anionic charge of the GBM, heparan sulfate chains have been thought to impart charge selectivity to the glomerular filtration, a view challenged by the negligible albuminuria in mice that lack heparan sulfate in the GBM. Recent studies provide increasing evidence that heparan sulfate chains modulate local complement activation by recruiting complement regulatory protein factor H, the major inhibitor of the alternative pathway in plasma. Factor H selectively inactivates C3b bound to surfaces bearing host-specific polyanions such as heparan sulfate, thus limiting complement activation on self surfaces such as the GBM, which are not protected by cell-bound complement regulators. We discuss mechanisms whereby the acquired loss of GBM heparan sulfate can impair the local regulation of the alternative pathway, exacerbating complement activation and glomerular injury in immune-mediated kidney diseases such as membranous nephropathy and lupus nephritis.
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Affiliation(s)
- Dorin-Bogdan Borza
- Department of Microbiology and Immunology, Meharry Medical College, 1005 Dr. D. B. Todd, Jr., Blvd., Nashville, TN 37208, USA.
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Marshall CB. Rethinking glomerular basement membrane thickening in diabetic nephropathy: adaptive or pathogenic? Am J Physiol Renal Physiol 2016; 311:F831-F843. [PMID: 27582102 DOI: 10.1152/ajprenal.00313.2016] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 08/21/2016] [Indexed: 12/12/2022] Open
Abstract
Diabetic nephropathy (DN) is the leading cause of chronic kidney disease in the United States and is a major cause of cardiovascular disease and death. DN develops insidiously over a span of years before clinical manifestations, including microalbuminuria and declining glomerular filtration rate (GFR), are evident. During the clinically silent period, structural lesions develop, including glomerular basement membrane (GBM) thickening, mesangial expansion, and glomerulosclerosis. Once microalbuminuria is clinically apparent, structural lesions are often considerably advanced, and GFR decline may then proceed rapidly toward end-stage kidney disease. Given the current lack of sensitive biomarkers for detecting early DN, a shift in focus toward examining the cellular and molecular basis for the earliest structural change in DN, i.e., GBM thickening, may be warranted. Observed within one to two years following the onset of diabetes, GBM thickening precedes clinically evident albuminuria. In the mature glomerulus, the podocyte is likely key in modifying the GBM, synthesizing and assembling matrix components, both in physiological and pathological states. Podocytes also secrete matrix metalloproteinases, crucial mediators in extracellular matrix turnover. Studies have shown that the critical podocyte-GBM interface is disrupted in the diabetic milieu. Just as healthy podocytes are essential for maintaining the normal GBM structure and function, injured podocytes likely have a fundamental role in upsetting the balance between the GBM's synthetic and degradative pathways. This article will explore the biological significance of GBM thickening in DN by reviewing what is known about the GBM's formation, its maintenance during health, and its disruption in DN.
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Affiliation(s)
- Caroline B Marshall
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and Department of Veterans Affairs Medical Center, Birmingham, Alabama
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Abstract
Genetic studies of hereditary forms of nephrotic syndrome have identified several proteins that are involved in regulating the permselective properties of the glomerular filtration system. Further extensive research has elucidated the complex molecular basis of the glomerular filtration barrier and clearly established the pivotal role of podocytes in the pathophysiology of glomerular diseases. Podocyte architecture is centred on focal adhesions and slit diaphragms - multiprotein signalling hubs that regulate cell morphology and function. A highly interconnected actin cytoskeleton enables podocytes to adapt in order to accommodate environmental changes and maintain an intact glomerular filtration barrier. Actin-based endocytosis has now emerged as a regulator of podocyte integrity, providing an impetus for understanding the precise mechanisms that underlie the steady-state control of focal adhesion and slit diaphragm components. This Review outlines the role of actin dynamics and endocytosis in podocyte biology, and discusses how molecular heterogeneity in glomerular disorders could be exploited to deliver more rational therapeutic interventions, paving the way for targeted medicine in nephrology.
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Kasinath BS. The podocyte and the proteoglycan. Am J Physiol Renal Physiol 2016; 311:F310-1. [PMID: 27226109 DOI: 10.1152/ajprenal.00295.2016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 05/18/2016] [Indexed: 11/22/2022] Open
Affiliation(s)
- Balakuntalam S Kasinath
- University of Texas Health Science Center, South Texas Veterans Health Care System, San Antonio, Texas
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Sugar T, Wassenhove-McCarthy DJ, Orr AW, Green J, van Kuppevelt TH, McCarthy KJ. N-sulfation of heparan sulfate is critical for syndecan-4-mediated podocyte cell-matrix interactions. Am J Physiol Renal Physiol 2016; 310:F1123-35. [PMID: 26936875 PMCID: PMC5002056 DOI: 10.1152/ajprenal.00603.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 02/26/2016] [Indexed: 12/23/2022] Open
Abstract
Previous research has shown that podocytes unable to assemble heparan sulfate on cell surface proteoglycan core proteins have compromised cell-matrix interactions. This report further explores the role of N-sulfation of intact heparan chains in podocyte-matrix interactions. For the purposes of this study, a murine model in which the enzyme N-deacetylase/N-sulfotransferase 1 (NDST1) was specifically deleted in podocytes and immortalized podocyte cell lines lacking NDST1 were developed and used to explore the effects of such a mutation on podocyte behavior in vitro. NDST1 is a bifunctional enzyme, ultimately responsible for N-sulfation of heparan glycosaminoglycans produced by cells. Immunostaining of glomeruli from mice whose podocytes were null for Ndst1 (Ndst1(-/-)) showed a disrupted pattern of localization for the cell surface proteoglycan, syndecan-4, and for α-actinin-4 compared with controls. The pattern of immunostaining for synaptopodin and nephrin did not show as significant alterations. In vitro studies showed that Ndst1(-/-) podocytes attached, spread, and migrated less efficiently than Ndst1(+/+) podocytes. Immunostaining in vitro for several markers for molecules involved in cell-matrix interactions showed that Ndst1(-/-) cells had decreased clustering of syndecan-4 and decreased recruitment of protein kinase-Cα, α-actinin-4, vinculin, and phospho-focal adhesion kinase to focal adhesions. Total intracellular phospho-focal adhesion kinase was decreased in Ndst1(-/-) compared with Ndst1(+/+) cells. A significant decrease in the abundance of activated integrin α5β1 on the cell surface of Ndst1(-/-) cells compared with Ndst1(+/+) cells was observed. These results serve to highlight the critical role of heparan sulfate N-sulfation in facilitating normal podocyte-matrix interactions.
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Affiliation(s)
- Terrel Sugar
- Department of Cell Biology and Anatomy, LSU Health Sciences Center, Shreveport, Louisiana
| | | | - A Wayne Orr
- Department of Pathology, LSU Health Sciences Center, Shreveport, Louisiana; and
| | - Jonette Green
- Department of Pathology, LSU Health Sciences Center, Shreveport, Louisiana; and
| | - Toin H van Kuppevelt
- Department of Biochemistry, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Kevin J McCarthy
- Department of Cell Biology and Anatomy, LSU Health Sciences Center, Shreveport, Louisiana; Department of Pathology, LSU Health Sciences Center, Shreveport, Louisiana; and
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36
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Garsen M, Benner M, Dijkman HB, van Kuppevelt TH, Li JP, Rabelink TJ, Vlodavsky I, Berden JHM, Rops ALWMM, Elkin M, van der Vlag J. Heparanase Is Essential for the Development of Acute Experimental Glomerulonephritis. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 186:805-15. [PMID: 26873445 DOI: 10.1016/j.ajpath.2015.12.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 11/26/2015] [Accepted: 12/08/2015] [Indexed: 01/20/2023]
Abstract
Heparanase, a heparan sulfate (HS)--specific endoglucuronidase, mediates the onset of proteinuria and renal damage during experimental diabetic nephropathy. Glomerular heparanase expression is increased in most proteinuric diseases. Herein, we evaluated the role of heparanase in two models of experimental glomerulonephritis, being anti-glomerular basement membrane and lipopolysaccharide-induced glomerulonephritis, in wild-type and heparanase-deficient mice. Induction of experimental glomerulonephritis led to an increased heparanase expression in wild-type mice, which was associated with a decreased glomerular expression of a highly sulfated HS domain, and albuminuria. Albuminuria was reduced in the heparanase-deficient mice in both models of experimental glomerulonephritis, which was accompanied by a better renal function and less renal damage. Notably, glomerular HS expression was preserved in the heparanase-deficient mice. Glomerular leukocyte and macrophage influx was reduced in the heparanase-deficient mice, which was accompanied by a reduced expression of both types 1 and 2 helper T-cell cytokines. In vitro, tumor necrosis factor-α and lipopolysaccharide directly induced heparanase expression and increased transendothelial albumin passage. Our study shows that heparanase contributes to proteinuria and renal damage in experimental glomerulonephritis by decreasing glomerular HS expression, enhancing renal leukocyte and macrophage influx, and affecting the local cytokine milieu.
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Affiliation(s)
- Marjolein Garsen
- Department of Nephrology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Marilen Benner
- Department of Nephrology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Henry B Dijkman
- Department of Pathology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Toin H van Kuppevelt
- Department of Biochemistry, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Jin-Ping Li
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Ton J Rabelink
- Department of Nephrology, Leiden University Medical Center, Leiden, the Netherlands
| | - Israel Vlodavsky
- Cancer and Vascular Biology Research Center, Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Jo H M Berden
- Department of Nephrology, Radboud University Medical Center, Nijmegen, the Netherlands
| | | | - Michael Elkin
- Sharett Institute, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Johan van der Vlag
- Department of Nephrology, Radboud University Medical Center, Nijmegen, the Netherlands.
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Abstract
The function of the kidney, filtering blood and concentrating metabolic waste into urine, takes place in an intricate and functionally elegant structure called the renal glomerulus. Normal glomerular function retains circulating cells and valuable macromolecular components of plasma in blood, resulting in urine with just trace amounts of proteins. Endothelial cells of glomerular capillaries, the podocytes wrapped around them, and the fused extracellular matrix these cells form altogether comprise the glomerular filtration barrier, a dynamic and highly selective filter that sieves on the basis of molecular size and electrical charge. Current understanding of the structural organization and the cellular and molecular basis of renal filtration draws from studies of human glomerular diseases and animal models of glomerular dysfunction.
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Affiliation(s)
- Rizaldy P Scott
- Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Susan E Quaggin
- Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
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Assady S, Alter J, Axelman E, Zohar Y, Sabo E, Litvak M, Kaplan M, Ilan N, Vlodavsky I, Abassi Z. Nephroprotective effect of heparanase in experimental nephrotic syndrome. PLoS One 2015; 10:e0119610. [PMID: 25786136 PMCID: PMC4364762 DOI: 10.1371/journal.pone.0119610] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Accepted: 02/01/2015] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Heparanase, an endoglycosidase that cleaves heparan sulfate (HS), is involved in various biologic processes. Recently, an association between heparanase and glomerular injury was suggested. The present study examines the involvement of heparanase in the pathogenesis of Adriamycin-induced nephrotic syndrome (ADR-NS) in a mouse model. METHODS BALB/c wild-type (wt) mice and heparanase overexpressing transgenic mice (hpa-TG) were tail-vein injected with either Adriamycin (ADR, 10 mg/kg) or vehicle. Albuminuria was investigated at days 0, 7, and 14 thereafter. Mice were sacrificed at day 15, and kidneys were harvested for various analyses: structure and ultrastructure alterations, podocyte proteins expression, and heparanase enzymatic activity. RESULTS ADR-injected wt mice developed severe albuminuria, while ADR-hpa-TG mice showed only a mild elevation in urinary albumin excretion. In parallel, light microscopy of stained cross sections of kidneys from ADR-injected wt mice, but not hpa-TG mice, showed mild to severe glomerular and tubular damage. Western blot and immunofluorescence analyses revealed significant reduction in nephrin and podocin protein expression in ADR-wt mice, but not in ADR-hpa-TG mice. These results were substantiated by electron-microscopy findings showing massive foot process effacement in injected ADR-wt mice, in contrast to largely preserved integrity of podocyte architecture in ADR-hpa-TG mice. CONCLUSIONS Our results suggest that heparanase may play a nephroprotective role in ADR-NS, most likely independently of HS degradation. Moreover, hpa-TG mice comprise an invaluable in vivo platform to investigate the interplay between heparanase and glomerular injury.
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Affiliation(s)
- Suheir Assady
- Department of Nephrology, Rambam Health Care Campus, Haifa, Israel
| | - Joel Alter
- Department of Nephrology, Rambam Health Care Campus, Haifa, Israel
| | - Elena Axelman
- Department of Nephrology, Rambam Health Care Campus, Haifa, Israel
| | - Yaniv Zohar
- Department of Pathology, Rambam Health Care Campus, Haifa, Israel
| | - Edmond Sabo
- Department of Pathology, Rambam Health Care Campus, Haifa, Israel
| | - Michael Litvak
- Department of Nephrology, Rambam Health Care Campus, Haifa, Israel
| | - Marielle Kaplan
- Clinical Laboratories Division, Rambam Health Care Campus, Haifa, Israel
| | - Neta Ilan
- Cancer and Vascular Biology Research Centre, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Israel Vlodavsky
- Cancer and Vascular Biology Research Centre, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Zaid Abassi
- Research Unit, Rambam Health Care Campus, Haifa, Israel; Department of Physiology, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
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The protective role of fucosylated chondroitin sulfate, a distinct glycosaminoglycan, in a murine model of streptozotocin-induced diabetic nephropathy. PLoS One 2014; 9:e106929. [PMID: 25192337 PMCID: PMC4156394 DOI: 10.1371/journal.pone.0106929] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 08/03/2014] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Heparanase-1 activation, albuminuria, and a decrease in glomerular heparan sulfate (HS) have been described in diabetic nephropathy (DN). Glycosaminoglycan (GAG)-based drugs have been shown to have renoprotective effects in this setting, although recent trials have questioned their clinical effectiveness. Here, we describe the effects of fucosylated chondroitin sulfate (FCS), a novel GAG extracted from a marine echinoderm, in experimentally induced DN compared to a widely used GAG, enoxaparin (ENX). METHODS Diabetes mellitus (DM) was induced by streptozotocin in male Wistar rats divided into three groups: DM (without treatment), FCS (8 mg/kg), and ENX (4 mg/kg), administered subcutaneously. After 12 weeks, we measured blood glucose, blood pressure, albuminuria, and renal function. The kidneys were evaluated for mesangial expansion and collagen content. Immunohistochemical quantifications of macrophages, TGF-β, nestin and immunofluorescence analysis of heparanase-1 and glomerular basement membrane (GBM) HS content was also performed. Gene expression of proteoglycan core proteins and enzymes involved in GAG assembly/degradation were analyzed by TaqMan real-time PCR. RESULTS Treatment with GAGs prevented albuminuria and did not affect the glucose level or other functional aspects. The DM group exhibited increased mesangial matrix deposition and tubulointerstitial expansion, and prevention was observed in both GAG groups. TGF-β expression and macrophage infiltration were prevented by the GAG treatments, and podocyte damage was halted. The diabetic milieu resulted in the down-regulation of agrin, perlecan and collagen XVIII mRNAs, along with the expression of enzymes involved in GAG biosynthesis. Treatment with FCS and ENX positively modulated such changes. Heparanase-1 expression was significantly reduced after GAG treatment without affecting the GBM HS content, which was uniformly reduced in all of the diabetic animals. CONCLUSIONS Our results demonstrate that the administration of FCS prevented several pathological features of ND in rats. This finding should stimulate further research on GAG treatment for this complication of diabetes.
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Mizumoto S, Yamada S, Sugahara K. Human genetic disorders and knockout mice deficient in glycosaminoglycan. BIOMED RESEARCH INTERNATIONAL 2014; 2014:495764. [PMID: 25126564 PMCID: PMC4122003 DOI: 10.1155/2014/495764] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 06/08/2014] [Indexed: 12/20/2022]
Abstract
Glycosaminoglycans (GAGs) are constructed through the stepwise addition of respective monosaccharides by various glycosyltransferases and maturated by epimerases and sulfotransferases. The structural diversity of GAG polysaccharides, including their sulfation patterns and sequential arrangements, is essential for a wide range of biological activities such as cell signaling, cell proliferation, tissue morphogenesis, and interactions with various growth factors. Studies using knockout mice of enzymes responsible for the biosynthesis of the GAG side chains of proteoglycans have revealed their physiological functions. Furthermore, mutations in the human genes encoding glycosyltransferases, sulfotransferases, and related enzymes responsible for the biosynthesis of GAGs cause a number of genetic disorders including chondrodysplasia, spondyloepiphyseal dysplasia, and Ehlers-Danlos syndromes. This review focused on the increasing number of glycobiological studies on knockout mice and genetic diseases caused by disturbances in the biosynthetic enzymes for GAGs.
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Affiliation(s)
- Shuji Mizumoto
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan
| | - Shuhei Yamada
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan
| | - Kazuyuki Sugahara
- Laboratory of Proteoglycan Signaling and Therapeutics, Frontier Research Center for Post-Genomic Science and Technology, Graduate School of Life Science, Hokkaido University, West-11, North-21, Kita-ku, Sapporo, Hokkaido 001-0021, Japan
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41
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Capobianco G, De Muro P, Lepedda AJ, Dessole M, Ambrosini G, Cherchi PL, Formato M. Impact of first trimester fasting glycemic levels on expression of proteoglycans in pregnancy. J Obstet Gynaecol Res 2014; 40:1625-31. [DOI: 10.1111/jog.12411] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 01/21/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Giampiero Capobianco
- Gynaecologic and Obstetric Clinic; Department of Surgical, Microsurgical and Medical Sciences
| | - Pierina De Muro
- Department of Biomedical Sciences; University of Sassari; Sassari
| | | | - Margherita Dessole
- Gynaecologic and Obstetric Clinic; Department of Surgical, Microsurgical and Medical Sciences
| | - Guido Ambrosini
- Gynaecologic and Obstetric Clinic; University of Padua; Padua Italy
| | - Pier Luigi Cherchi
- Gynaecologic and Obstetric Clinic; Department of Surgical, Microsurgical and Medical Sciences
| | - Marilena Formato
- Department of Biomedical Sciences; University of Sassari; Sassari
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Modulation of heparan sulfate in the glomerular endothelial glycocalyx decreases leukocyte influx during experimental glomerulonephritis. Kidney Int 2014; 86:932-42. [PMID: 24759151 DOI: 10.1038/ki.2014.115] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 02/25/2014] [Accepted: 03/06/2014] [Indexed: 11/08/2022]
Abstract
The glomerular endothelial glycocalyx is postulated to be an important modulator of permeability and inflammation. The glycocalyx consists of complex polysaccharides, the main functional constituent of which, heparan sulfate (HS), is synthesized and modified by multiple enzymes. The N-deacetylase-N-sulfotransferase (Ndst) enzymes initiate and dictate the modification process. Here we evaluated the effects of modulation of HS in the endothelial glycocalyx on albuminuria and glomerular leukocyte influx using mice deficient in endothelial and leukocyte Ndst1 (TEKCre+/Ndst1flox/flox). In these mice, glomerular expression of a specific HS domain was significantly decreased, whereas the expression of other HS domains was normal. In the endothelial glycocalyx, this specific HS structure was not associated with albuminuria or with changes in renal function. However, glomerular leukocyte influx was significantly reduced during antiglomerular basement membrane nephritis, which was associated with less glomerular injury and better renal function. In vitro decreased adhesion of wild-type and Ndst1-deficient granulocytes to Ndst1-silenced glomerular endothelial cells was found, accompanied by a decreased binding of chemokines and L-selectin. Thus, modulation of HS in the glomerular endothelial glycocalyx significantly reduced the inflammatory response in antiglomerular basement membrane nephritis.
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43
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Interclass small leucine-rich repeat proteoglycan interactions regulate collagen fibrillogenesis and corneal stromal assembly. Matrix Biol 2014; 35:103-11. [PMID: 24447998 DOI: 10.1016/j.matbio.2014.01.004] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 01/08/2014] [Accepted: 01/08/2014] [Indexed: 01/22/2023]
Abstract
The corneal stroma is enriched in small leucine-rich proteoglycans (SLRPs), including both class I (decorin and biglycan) and class II (lumican, keratocan and fibromodulin). Transparency is dependent on the assembly and maintenance of a hierarchical stromal organization and SLRPs are critical regulatory molecules. We hypothesize that cooperative interclass SLRP interactions are involved in the regulation of stromal matrix assembly. We test this hypothesis using a compound Bgn(-/0)/Lum(-/-) mouse model and single Lum(-/-) or Bgn(-/0) mouse models and wild type controls. SLRP expression was investigated using immuno-localization and immuno-blots. Structural relationships were defined using ultrastructural and morphometric approaches while transparency was analyzed using in vivo confocal microscopy. The compound Bgn(-/0)/Lum(-/-) corneas demonstrated gross opacity that was not seen in the Bgn(-/0) or wild type corneas and greater than that in the Lum(-/-) mice. The Bgn(-/0)/Lum(-/-) corneas exhibited significantly increased opacity throughout the stroma compared to posterior opacity in the Lum(-/-) and no opacity in Bgn(-/0) or wild type corneas. In the Bgn(-/0)/Lum(-/-) corneas there were abnormal lamellar and fibril structures consistent with the functional deficit in transparency. Lamellar structure was disrupted across the stroma with disorganized fibrils, and altered fibril packing. In addition, fibrils had larger and more heterogeneous diameters with an abnormal structure consistent with abnormal fibril growth. This was not observed in the Bgn(-/0) or wild type corneas and was restricted to the posterior stroma in Lum(-/-) mice. The data demonstrate synergistic interclass regulatory interactions between lumican and biglycan. These interactions are involved in regulating both lamellar structure as well as collagen fibrillogenesis and therefore, corneal transparency.
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Lennon R, Randles MJ, Humphries MJ. The importance of podocyte adhesion for a healthy glomerulus. Front Endocrinol (Lausanne) 2014; 5:160. [PMID: 25352829 PMCID: PMC4196579 DOI: 10.3389/fendo.2014.00160] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 09/21/2014] [Indexed: 12/23/2022] Open
Abstract
Podocytes are specialized epithelial cells that cover the outer surfaces of glomerular capillaries. Unique cell junctions, known as slit diaphragms, which feature nephrin and Neph family proteins in addition to components of adherens, tight, and gap junctions, connect adjacent podocyte foot processes. Single gene disorders affecting the slit diaphragm result in nephrotic syndrome in humans, characterized by massive loss of protein across the capillary wall. In addition to specialized cell junctions, interconnecting podocytes also adhere to the glomerular basement membrane (GBM) of the capillary wall. The GBM is a dense network of secreted, extracellular matrix (ECM) components and contains tissue-restricted isoforms of collagen IV and laminin in addition to other structural proteins and ECM regulators such as proteases and growth factors. The specialized niche of the GBM provides a scaffold for endothelial cells and podocytes to support their unique functions and human genetic mutations in GBM components lead to renal failure, thus highlighting the importance of cell-matrix interactions in the glomerulus. Cells adhere to ECM via adhesion receptors, including integrins, syndecans, and dystroglycan and in particular the integrin heterodimer α3β1 is required to maintain barrier integrity. Therefore, the sophisticated function of glomerular filtration relies on podocyte adhesion both at cell junctions and at the interface with the ECM. In health, the podocyte coordinates signals from cell junctions and cell-matrix interactions, in response to environmental cues in order to regulate filtration and as our understanding of mechanisms that control cell adhesion in the glomerulus develops, then insight into the effects of disease will improve. The ultimate goal will be to develop targeted therapies to prevent or repair defects in the filtration barrier and to restore glomerular function.
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Affiliation(s)
- Rachel Lennon
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, The University of Manchester, Manchester, UK
- Institute of Human Development, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, UK
- Department of Paediatric Nephrology, Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
- *Correspondence: Rachel Lennon, Wellcome Trust Centre for Cell-Matrix Research, The University of Manchester, Michael Smith Building, Manchester M13 9PT, UK e-mail:
| | - Michael J. Randles
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, The University of Manchester, Manchester, UK
- Institute of Human Development, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, UK
| | - Martin J. Humphries
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, The University of Manchester, Manchester, UK
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Garsen M, Rops AL, Rabelink TJ, Berden JH, van der Vlag J. The role of heparanase and the endothelial glycocalyx in the development of proteinuria. Nephrol Dial Transplant 2013; 29:49-55. [DOI: 10.1093/ndt/gft410] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Yoneda H, Ueta K, Nagasaki M, Arakawa K. Involvement of heparan sulfate in the renoprotective effects of imidapril, an angiotensin-converting enzyme inhibitor, in diabetic db/db mice. J Recept Signal Transduct Res 2013; 34:21-5. [PMID: 24094140 DOI: 10.3109/10799893.2013.845788] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We investigated the renoprotective effects of imidapril hydrochloride ((-)-(4 S)-3-[(2 S)-2-[[(1 S)-1-ethoxycarbonyl-3-phenylpropyl] amino] propionyl]-1-methyl-2-oxoimidazolidine-4-carboxylic acid hydrochloride, imidapril), an angiotensin-converting enzyme inhibitor, in a diabetic animal model. We used BKS.Cg-+Lepr(db)/+Lepr(db) (db/db) mice, a genetic animal model of obese type 2 diabetes. Diabetic db/db mice suffered from glomerular hyperfiltration, albuminuria and hypoalbuminemia. Oral administration of 5 mg/kg/day of imidapril for 3 weeks suppressed renal hyperfiltration, reduced albuminuria and normalized hypoalbuminemia. Imidapril did not influence body weights, blood pressure or blood glucose concentrations in db/db mice. Urinary excretion of heparan sulfate (HS) in non-treated 11-week-old db/db mice was significantly lower than that in age-matched non-diabetic db/+m mice. HS is a component of HS proteoglycans, which are present in glomerular basement membranes and glycocalyx of cell surfaces. Reduced urinary HS excretion indicated glomerular HS loss in db/db mice. Imidapril increased urinary excretion of HS to concentrations observed in db/+m mice, indicating that imidapril prevented the loss of renal HS. These results suggest that imidapril ameliorates renal hyperfiltration and loss of renal contents of HS. Improvement of filtration function and maintenance of HS, which is an important structural component of glomeruli, may contribute to renoprotective effects of imidapril.
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Affiliation(s)
- Hikaru Yoneda
- Pharmacology Research Laboratories II, Mitsubishi Tanabe Pharma Corporation , Kawagishi, Toda-shi, Saitama , Japan
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47
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Sugar T, Wassenhove-McCarthy DJ, Esko JD, van Kuppevelt TH, Holzman L, McCarthy KJ. Podocyte-specific deletion of NDST1, a key enzyme in the sulfation of heparan sulfate glycosaminoglycans, leads to abnormalities in podocyte organization in vivo. Kidney Int 2013; 85:307-18. [PMID: 23924956 PMCID: PMC4624314 DOI: 10.1038/ki.2013.281] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 05/03/2013] [Accepted: 05/23/2013] [Indexed: 01/18/2023]
Abstract
Heparan sulfate proteoglycans have been shown to modulate podocyte adhesion to- and pedicel organization on- the glomerular basement membrane. Recent studies showed that foot process effacement developed in a mutant mouse model whose podocytes were unable to assemble heparan sulfate glycosaminoglycan chains. This study, a further refinement, explored the role of heparan N-sulfation on podocyte behavior. A novel mutant mouse (Ndst1-/-) was developed, having podocyte-specific deletion of NDST1, the enzyme responsible for N-sulfation of heparan sulfate chains. Podocytes having this mutation had foot process effacement and abnormal adhesion to Bowman's capsule. Although glomerular hypertrophy did develop in the kidneys of mutant animals, mesangial expansion was not seen. The lack of heparan N-sulfation did not affect the expression of agrin or perlecan proteoglycan core proteins. Loss of N-sulfation did not result in significant proteinuria, but the increase in the albumin/creatinine ratio was coincident with the development of the enlarged lysosomes in the proximal tubules. Thus, although the renal phenotype of the Ndst1-/- mouse is mild, the data show that heparan chain N-sulfation plays a key role in podocyte organization.
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Affiliation(s)
- Terrel Sugar
- Department of Cell Biology and Anatomy, LSU Health Sciences Center, Shreveport, Louisiana, USA
| | | | - Jeffrey D Esko
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, San Diego, California, USA
| | - Toin H van Kuppevelt
- Department of Biochemistry, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Lawrence Holzman
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kevin J McCarthy
- 1] Department of Cell Biology and Anatomy, LSU Health Sciences Center, Shreveport, Louisiana, USA [2] Department of Pathology, LSU Health Sciences Center, Shreveport, Louisiana, USA
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Reine TM, Grøndahl F, Jenssen TG, Hadler-Olsen E, Prydz K, Kolset SO. Reduced sulfation of chondroitin sulfate but not heparan sulfate in kidneys of diabetic db/db mice. J Histochem Cytochem 2013; 61:606-16. [PMID: 23757342 DOI: 10.1369/0022155413494392] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Heparan sulfate proteoglycans are hypothesized to contribute to the filtration barrier in kidney glomeruli and the glycocalyx of endothelial cells. To investigate potential changes in proteoglycans in diabetic kidney, we isolated glycosaminoglycans from kidney cortex from healthy db/+ and diabetic db/db mice. Disaccharide analysis of chondroitin sulfate revealed a significant decrease in the 4-O-sulfated disaccharides (D0a4) from 65% to 40%, whereas 6-O-sulfated disaccharides (D0a6) were reduced from 11% to 6%, with a corresponding increase in unsulfated disaccharides. In contrast, no structural differences were observed in heparan sulfate. Furthermore, no difference was found in the molar amount of glycosaminoglycans, or in the ratio of hyaluronan/heparan sulfate/chondroitin sulfate. Immunohistochemical staining for the heparan sulfate proteoglycan perlecan was similar in both types of material but reduced staining of 4-O-sulfated chondroitin and dermatan was observed in kidney sections from diabetic mice. In support of this, using qRT-PCR, a 53.5% decrease in the expression level of Chst-11 (chondroitin 4-O sulfotransferase) was demonstrated in diabetic kidney. These results suggest that changes in the sulfation of chondroitin need to be addressed in future studies on proteoglycans and kidney function in diabetes.
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Affiliation(s)
- Trine M Reine
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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Sachs N, Sonnenberg A. Cell-matrix adhesion of podocytes in physiology and disease. Nat Rev Nephrol 2013; 9:200-10. [PMID: 23338211 DOI: 10.1038/nrneph.2012.291] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Cell-matrix adhesion is crucial for maintaining the mechanical integrity of epithelial tissues. Podocytes--a key component of the glomerular filtration barrier--are exposed to permanent transcapillary filtration pressure and must therefore adhere tightly to the underlying glomerular basement membrane (GBM). The major cell-matrix adhesion receptor in podocytes is the integrin α3β1, which connects laminin 521 in the GBM through various adaptor proteins to the intracellular actin cytoskeleton. Other cell-matrix adhesion receptors expressed by podocytes include the integrins α2β1 and αvβ3, α-dystroglycan, syndecan-4 and type XVII collagen. Mutations in genes encoding any of the components critical for podocyte adhesion cause glomerular disease. This Review highlights recent advances in our understanding of the cell biology and genetics of podocyte adhesion with special emphasis on glomerular disease.
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Affiliation(s)
- Norman Sachs
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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50
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Abstract
The glomerular filtration barrier is a highly specialized blood filtration interface that displays a high conductance to small and midsized solutes in plasma but retains relative impermeability to macromolecules. Its integrity is maintained by physicochemical and signalling interplay among its three core constituents-the glomerular endothelial cell, the basement membrane and visceral epithelial cell (podocyte). Understanding the pathomechanisms of inherited and acquired human diseases as well as experimental injury models of this barrier have helped to unravel this interdependence. Key among the consequences of interference with the integrity of the glomerular filtration barrier is the appearance of significant amounts of proteins in the urine. Proteinuria correlates with kidney disease progression and cardiovascular mortality. With specific reference to proteinuria in human and animal disease phenotypes, the following review explores the roles of the endothelial cell, glomerular basement membrane, and the podocyte and attempts to highlight examples of essential crosstalk within this barrier.
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