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Verma PR, Patil P. Nephrotic Syndrome: A Review. Cureus 2024; 16:e53923. [PMID: 38465146 PMCID: PMC10924861 DOI: 10.7759/cureus.53923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 02/09/2024] [Indexed: 03/12/2024] Open
Abstract
Nephrotic syndrome (NS) is characterized by hypoalbuminemia, severe proteinuria, and peripheral edema, frequently in conjunction with hyperlipidemia. Individuals usually show symptoms of weariness and swelling, but no signs of serious liver damage or cardiac failure. With characteristic medical symptoms and evidence of hypoalbuminemia and severe proteinuria, NS can be diagnosed. The majority of NS episodes are classified as unexplained or primary; the most prevalent histopathological subgroups of primary NS in people are focal segmental glomerulosclerosis and membraneous nephropathy. Thrombosis of the veins with high cholesterol levels is a significant NS risk. Acute renal damage and infection are further possible side effects. The pathobiochemistry of NS involves alterations in genes that affect the selectivity of the kidneys and abnormalities in proteins related to podocytes. Understanding the molecular mechanisms that influence these processes is crucial to developing specific and targeted therapeutic approaches. The need for invasive renal biopsies throughout the diagnosis process may be lessened by the development of non-invasive nephrotic syndrome biomarkers, such as microRNAs. Corticosteroids are frequently used as the initial line of defense in NS treatment. However, some individuals need other treatments since a resistant type of NS also exists. The use of calcineurin inhibitors, mycophenolate mofetil, and rituximab is mentioned in the text, along with current research to identify safer and more efficient therapeutic choices. The complicated kidney condition NS has several underlying causes and symptoms. For the diagnosis of this ailment as well as the creation of focused therapies, an understanding of the pathophysiology and the identification of possible biomarkers are essential.
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Affiliation(s)
- Priyanshu R Verma
- Medicine, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Praful Patil
- Microbiology, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
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2
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Metin H, Ertan P, KeskinoÄŸlu A, Türköz Uluer E, Batir MB, KeskinoÄŸlu P, Akogullari D, Çam FS. Effect of vitamin D analogues calcitriol and paricalcitol in a rat model of puromycin aminonucleoside-induced nephrotic syndrome. PAEDIATRICA INDONESIANA 2022. [DOI: 10.14238/pi62.6.2022.382-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Background Renoprotective effects of vitamin D analogues have been shown in several experimental and clinical studies, the exact mechanism of the therapeutic effectiveness of these analogues in Nephrotic syndrome remains unclear, and these are relatively few studies on potential treatment roles for vitamin D analogues in nephrotic-range proteinuria. ?ndicate similar efficacy of the vitamin D analogues calcitriol and paricalcitol in time-limited amelioration of proteinuria in nephrotic syndrome, yet suggest the likelihood of mechanisms other than direct upregulation of nephrin and podocin in podocytes underlie the renoprotective effects of vitamin D analogues.
Objective To investigate the effect of vitamin D (Vit D) analogues calcitriol and paricalcitol on urinary protein/creatinine ratio (UPCR) and renal podocin and nephrin expression in a rat model of puromycin aminonucleoside (PAN)-induced nephrotic syndrome (NS).
Methods A total of 28 male Wistar Albino rats were separated into 4 groups (n=7 for each) including CON [control; intraperitoneal (IP) saline injection], PAN (NS + IP saline injection), PAN-C (NS + IP 0.4 µg/kg/day calcitriol injection), and PAN-P (NS + IP 240 ng/kg/day paricalcitol injection). Nephrotic syndrome was induced via intravenous (IV) administration of 10mg/100gr PAN. The UPCR as well as histopathological, immuno-histochemical, and real time PCR analyses of kidney tissue specimens were recorded and analyzed among the 4 groups.
Results Median UPCR (Day 4) was significantly lower in both the PAN-C [1.45 (range 1.20-1.80)] and PAN-P [1.40 (range 1.10-1.80)] groups than in the PAN group [2.15 (range 2.00-2.40)] (P<0.01 for each). The PAN group had significantly higher mean UPCR than the CON group [1.75 (range 1.40-2.00); P<0.05]. No significant difference in UPCR was noted between groups on Day 7. Median podocin mRNA expression was significantly higher in the PAN-P group compared to the PAN group [22.55 (range 22.42-23.02) vs. 22.06 (range 21.81-22.06), respectively; (P<0.01)].
Conclusion Seven-day calcitriol and paricalcitol supplementation in a rat model of PAN-induced nephrotic syndrome had similar efficacy, in terms of temporary amelioration of proteinuria.
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3
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Paul A, Annunziato S, Lu B, Sun T, Evrova O, Planas-Paz L, Orsini V, Terracciano LM, Charlat O, Loureiro ZY, Ji L, Zamponi R, Sigoillot F, Lei H, Lindeman A, Russ C, Reece-Hoyes JS, Nicholson TB, Tchorz JS, Cong F. Cell adhesion molecule KIRREL1 is a feedback regulator of Hippo signaling recruiting SAV1 to cell-cell contact sites. Nat Commun 2022; 13:930. [PMID: 35177623 PMCID: PMC8854406 DOI: 10.1038/s41467-022-28567-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 01/31/2022] [Indexed: 12/11/2022] Open
Abstract
The Hippo/YAP pathway controls cell proliferation through sensing physical and spatial organization of cells. How cell-cell contact is sensed by Hippo signaling is poorly understood. Here, we identified the cell adhesion molecule KIRREL1 as an upstream positive regulator of the mammalian Hippo pathway. KIRREL1 physically interacts with SAV1 and recruits SAV1 to cell-cell contact sites. Consistent with the hypothesis that KIRREL1-mediated cell adhesion suppresses YAP activity, knockout of KIRREL1 increases YAP activity in neighboring cells. Analyzing pan-cancer CRISPR proliferation screen data reveals KIRREL1 as the top plasma membrane protein showing strong correlation with known Hippo regulators, highlighting a critical role of KIRREL1 in regulating Hippo signaling and cell proliferation. During liver regeneration in mice, KIRREL1 is upregulated, and its genetic ablation enhances hepatic YAP activity, hepatocyte reprogramming and biliary epithelial cell proliferation. Our data suggest that KIRREL1 functions as a feedback regulator of the mammalian Hippo pathway through sensing cell-cell interaction and recruiting SAV1 to cell-cell contact sites.
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Affiliation(s)
- Atanu Paul
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Stefano Annunziato
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Bo Lu
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Tianliang Sun
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Olivera Evrova
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Lara Planas-Paz
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Vanessa Orsini
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Luigi M Terracciano
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele (Milan), Italy.,IRCCS Humanitas Research Hospital, Rozzano (Milan), Italy
| | - Olga Charlat
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Zinger Yang Loureiro
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Lei Ji
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Raffaella Zamponi
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Frederic Sigoillot
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Hong Lei
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Alicia Lindeman
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Carsten Russ
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - John S Reece-Hoyes
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Thomas B Nicholson
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Jan S Tchorz
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Feng Cong
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA.
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4
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A descriptive study of NPHS1 and NPHS2 mutations in children with congenital nephrotic syndrome. GENE REPORTS 2020. [DOI: 10.1016/j.genrep.2020.100722] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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5
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Structural features and oligomeric nature of human podocin domain. Biochem Biophys Rep 2020; 23:100774. [PMID: 32617419 PMCID: PMC7322680 DOI: 10.1016/j.bbrep.2020.100774] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/31/2020] [Accepted: 06/02/2020] [Indexed: 12/29/2022] Open
Abstract
Podocytes are crucial cells of the glomerular filtration unit and plays a vital role at the interface of the blood-urine barrier. Podocyte slit-diaphragm is a modified tight junction that facilitates size and charge-dependent permselectivity. Several proteins including podocin, nephrin, CD2AP, and TRPC6 form a macromolecular assembly and constitute the slit-diaphragm. Podocin is an integral membrane protein attached to the inner membrane of the podocyte via a short transmembrane region (101–125). The cytosolic N- and C-terminus help podocin to attain a hook-like structure. Podocin shares 44% homology with stomatin family proteins and similar to the stomatin proteins, podocin was shown to associate into higher-order oligomers at the site of slit-diaphragm. However, the stoichiometry of the homo-oligomers and how it partakes in the macromolecular assemblies with other slit-diaphragm proteins remains elusive. Here we investigated the oligomeric propensity of a truncated podocin construct (residues:126–350). We show that the podocin domain majorly homo-oligomerizes into a 16-mer. Circular dichroism and fluorescence spectroscopy suggest that the 16-mer oligomer has considerable secondary structure and moderate tertiary packing. Cloning, expression, and purification of truncated podocin (residues: 126–350). The truncated podocin predominantly associates into 16mer oligomers. The oligomers though possesses secondary structure lacks tight tertiary packing. The oligomeric ensemble has different dissociation temperatures.
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Key Words
- CD, Circular dichroism
- CD2AP, CD-2 associated protein
- GFB, Glomerular filtration barrier
- IDRs, Intrinsically disordered regions
- MALS, multi-angle light scattering
- NEPH, Nephrin-like protein
- NPHS1 & 2, Nephrotic syndrome-type I and type II
- NS, Nephrotic syndrome
- Nephrotic syndrome
- Podocin
- Podocyte
- Proteinuria
- SD, slit-diaphragm
- SEC, Size-exclusion chromatography
- SRNS, steroid-resistant NS
- Slit-diaphragm
- TRPC6, Transient receptor potential cation channel subfamily C member 6
- ZO-1, Zonula occludens-1
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El-Far AH, Lebda MA, Noreldin AE, Atta MS, Elewa YHA, Elfeky M, Mousa SA. Quercetin Attenuates Pancreatic and Renal D-Galactose-Induced Aging-Related Oxidative Alterations in Rats. Int J Mol Sci 2020; 21:E4348. [PMID: 32570962 PMCID: PMC7352460 DOI: 10.3390/ijms21124348] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/11/2020] [Accepted: 06/15/2020] [Indexed: 02/07/2023] Open
Abstract
Aging is an oxidative stress-associated process that progresses with age. Our aim is to delay or attenuate these oxidative alterations and to keep individuals healthy as they age using natural compounds supplementation. Therefore, we conducted the present study to investigate the protective potentials of quercetin against D-galactose (D-gal)-associated oxidative alterations that were induced experimentally in male Wistar rats. Forty-five rats were randomly allocated into five groups of nine rats each. The groups were a control group that was reared on a basal diet and injected subcutaneously with 120 mg D-gal dissolved in physiological saline solution (0.9% NaCl) per kg body weight daily and quercetin-treated groups that received the same basal diet and subcutaneous daily D-gal injections were supplemented orally with 25, 50, and 100 mg of quercetin per kg body weight for 42 days. Pancreatic and renal samples were subjected to histopathological, immunohistochemical, and relative mRNA expression assessments. Aging (p53, p21, IL-6, and IL-8), apoptotic (Bax, CASP-3, and caspase-3 protein), proliferative (Ki67 protein), antiapoptotic (Bcl2 and Bcl2 protein), inflammatory (NF-κB, IL-1β, and TNF-α), antioxidant (SOD1), and functional markers (GCLC and GCLM genes and insulin, glucagon, and podocin proteins) were determined to evaluate the oxidative alterations induced by D-gal and the protective role of quercetin. D-gal caused oxidative alterations of the pancreas and kidneys observed via upregulations of aging, apoptotic, and inflammatory markers and downregulated the antiapoptotic, proliferative, antioxidant, and functional markers. Quercetin potentially attenuated these aging-related oxidative alterations in a dose-dependent manner. Finally, we can conclude that quercetin supplementation is considered as a promising natural protective compound that could be used to delay the aging process and to maintain human health.
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Affiliation(s)
- Ali H. El-Far
- Department of Biochemistry, Faculty of Veterinary Medicine, Damanhour University, Damanhour 22511, Egypt
| | - Mohamed A. Lebda
- Biochemistry Department, Faculty of Veterinary Medicine, Alexandria University, Alexandria 22758, Egypt; (M.A.L.); (M.E.)
| | - Ahmed E. Noreldin
- Histology and Cytology Department, Faculty of Veterinary Medicine, Damanhour University, Damanhour 22511, Egypt;
| | - Mustafa S. Atta
- Department of Physiology, Faculty of Veterinary Medicine, Kafrelsheikh University, Kafrelsheikh 33516, Egypt;
| | - Yaser H. A. Elewa
- Histology and Cytology Department, Faculty of Veterinary Medicine, Zagazig University, Zagazig 44519, Egypt;
- Laboratory of Anatomy, Faculty of Veterinary Medicine, Basic Veterinary Sciences, Hokkaido University, Sapporo 060-0818, Japan
| | - Mohamed Elfeky
- Biochemistry Department, Faculty of Veterinary Medicine, Alexandria University, Alexandria 22758, Egypt; (M.A.L.); (M.E.)
| | - Shaker A. Mousa
- Pharmaceutical Research Institute, Albany College of Pharmacy and Health Sciences, Rensselaer, NY 12144, USA
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Andrikou C, Thiel D, Ruiz-Santiesteban JA, Hejnol A. Active mode of excretion across digestive tissues predates the origin of excretory organs. PLoS Biol 2019; 17:e3000408. [PMID: 31356592 PMCID: PMC6687202 DOI: 10.1371/journal.pbio.3000408] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 08/08/2019] [Accepted: 07/12/2019] [Indexed: 11/21/2022] Open
Abstract
Most bilaterian animals excrete toxic metabolites through specialized organs, such as nephridia and kidneys, which share morphological and functional correspondences. In contrast, excretion in non-nephrozoans is largely unknown, and therefore the reconstruction of ancestral excretory mechanisms is problematic. Here, we investigated the excretory mode of members of the Xenacoelomorpha, the sister group to Nephrozoa, and Cnidaria, the sister group to Bilateria. By combining gene expression, inhibitor experiments, and exposure to varying environmental ammonia conditions, we show that both Xenacoelomorpha and Cnidaria are able to excrete across digestive-associated tissues. However, although the cnidarian Nematostella vectensis seems to use diffusion as its main excretory mode, the two xenacoelomorphs use both active transport and diffusion mechanisms. Based on these results, we propose that digestive-associated tissues functioned as excretory sites before the evolution of specialized organs in nephrozoans. We conclude that the emergence of a compact, multiple-layered bilaterian body plan necessitated the evolution of active transport mechanisms, which were later recruited into the specialized excretory organs.
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Affiliation(s)
- Carmen Andrikou
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Daniel Thiel
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | | | - Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
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8
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Mulukala Narasimha SK, Kar PP, Vadrevu R, Pasupulati AK. Intrinsically disordered regions mediate macromolecular assembly of the Slit diaphragm proteins associated with Nephrotic syndrome. MOLECULAR SIMULATION 2019. [DOI: 10.1080/08927022.2019.1570508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
| | - Prajna Parimita Kar
- Laboratory of Molecular Interactions, National Institute of Animal Biotechnology, Hyderabad, India
| | - Ramakrishna Vadrevu
- Department of Biological Sciences, BITS-Pilani, Hyderabad Campus, Hyderabad, India
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9
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Cil O, Perwad F. Monogenic Causes of Proteinuria in Children. Front Med (Lausanne) 2018; 5:55. [PMID: 29594119 PMCID: PMC5858124 DOI: 10.3389/fmed.2018.00055] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 02/15/2018] [Indexed: 01/02/2023] Open
Abstract
Glomerular disease is a common cause for proteinuria and chronic kidney disease leading to end-stage renal disease requiring dialysis or kidney transplantation in children. Nephrotic syndrome in children is diagnosed by the presence of a triad of proteinuria, hypoalbuminemia, and edema. Minimal change disease is the most common histopathological finding in children and adolescents with nephrotic syndrome. Focal segmental sclerosis is also found in children and is the most common pathological finding in patients with monogenic causes of nephrotic syndrome. Current classification system for nephrotic syndrome is based on response to steroid therapy as a majority of patients develop steroid sensitive nephrotic syndrome regardless of histopathological diagnosis or the presence of genetic mutations. Recent studies investigating the genetics of nephrotic syndrome have shed light on the pathophysiology and mechanisms of proteinuria in nephrotic syndrome. Gene mutations have been identified in several subcellular compartments of the glomerular podocyte and play a critical role in mitochondrial function, actin cytoskeleton dynamics, cell-matrix interactions, slit diaphragm, and podocyte integrity. A subset of genetic mutations are known to cause nephrotic syndrome that is responsive to immunosuppressive therapy but clinical data are limited with respect to renal prognosis and disease progression in a majority of patients. To date, more than 50 genes have been identified as causative factors in nephrotic syndrome in children and adults. As genetic testing becomes more prevalent and affordable, we expect rapid advances in our understanding of mechanisms of proteinuria and genetic diagnosis will help direct future therapy for individual patients.
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Affiliation(s)
- Onur Cil
- Department of Pediatrics, Division of Nephrology, University of California San Francisco, San Francisco, CA, United States
| | - Farzana Perwad
- Department of Pediatrics, Division of Nephrology, University of California San Francisco, San Francisco, CA, United States
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10
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Trohatou O, Tsilibary EF, Charonis A, Iatrou C, Drossopoulou G. Vitamin D3 ameliorates podocyte injury through the nephrin signalling pathway. J Cell Mol Med 2017; 21:2599-2609. [PMID: 28664547 PMCID: PMC5618699 DOI: 10.1111/jcmm.13180] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 02/24/2017] [Indexed: 12/19/2022] Open
Abstract
Renal podocytes form the main filtration barrier possessing unique phenotype maintained by proteins including podocalyxin and nephrin, which are modulated in pathological conditions. In diabetic nephropathy (DN), podocytes become structurally and functionally compromised. Nephrin, a structural backbone protein of the slit diaphragm, acts as regulator of podocyte intracellular signalling with renoprotective role. Vitamin D3 through its receptor, VDR, provides renal protection in DN but limited data exist about its effect on podocytes. In this study, we used isolated rat glomeruli to assess podocalyxin and nephrin expression after treatment with the 1,25‐dihydroxyvitamin D3 analogue paricalcitol in the presence of normal and diabetic glucose levels. The role of 1,25‐dihydroxyvitamin D3 (calcitriol) and its analogue, paricalcitol, on podocyte morphology and survival was also investigated in the streptozotocin (STZ)‐diabetic animal model. In our ex vivo model, glomeruli exhibited high glucose‐mediated down‐regulation of podocalyxin, and nephrin, while paricalcitol reversed the high glucose‐induced decrease of nephrin and podocalyxin expression. Paricalcitol treatment enhanced VDR expression and promoted VDR and RXR co‐localization in the nucleus. Our data also indicated that hyperglycaemia impaired survival of cultured glomeruli and suggested that the implemented nephrin down‐regulation was reversed by paricalcitol treatment, initiating Akt signal transduction which may be involved in glomerular survival. Our findings were further verified in vivo, as in the STZ‐diabetic animal model, calcitriol and paricalcitol treatment resulted in significant amelioration of hyperglycaemia and restoration of nephrin signalling, suggesting that calcitriol and paricalcitol may provide molecular bases for protection against loss of the permselective renal barrier in DN.
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Affiliation(s)
- Ourania Trohatou
- Institute of Biosciences and Applications, NCSR 'Demokritos', Athens, Greece
| | | | - Aristidis Charonis
- Center for Clinical, Experimental Surgery and Translational Research, Biomedical Research Foundation Academy of Athens (BRFAA), Athens, Greece
| | - Christos Iatrou
- Center for Nephrology, G. Papadakis General Hospital of Nikea-Pireaus, Athens, Greece
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11
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Bickley LK, van Aerle R, Brown AR, Hargreaves A, Huby R, Cammack V, Jackson R, Santos EM, Tyler CR. Bioavailability and Kidney Responses to Diclofenac in the Fathead Minnow (Pimephales promelas). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:1764-1774. [PMID: 28068076 DOI: 10.1021/acs.est.6b05079] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Diclofenac is one of the most widely prescribed nonsteroidal anti-inflammatory drugs worldwide. It is frequently detected in surface waters; however, whether this pharmaceutical poses a risk to aquatic organisms is debated. Here we quantified the uptake of diclofenac by the fathead minnow (Pimephales promelas) following aqueous exposure (0.2-25.0 μg L-1) for 21 days, and evaluated the tissue and biomolecular responses in the kidney. Diclofenac accumulated in a concentration- and time-dependent manner in the plasma of exposed fish. The highest plasma concentration observed (for fish exposed to 25 μg L-1 diclofenac) was within the therapeutic range for humans. There was a strong positive correlation between exposure concentration and the number of developing nephrons observed in the posterior kidney. Diclofenac was not found to modulate the expression of genes in the kidney associated with its primary mode of action in mammals (prostaglandin-endoperoxide synthases) but modulated genes associated with kidney repair and regeneration. There were no significant adverse effects following 21 days exposure to concentrations typical of surface waters. The combination of diclofenac's uptake potential, effects on kidney nephrons and relatively small safety margin for some surface waters may warrant a longer term chronic health effects analysis for diclofenac in fish.
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Affiliation(s)
- Lisa K Bickley
- Biosciences, College of Life and Environmental Sciences, University of Exeter , Exeter, EX4 4QD, U.K
| | - Ronny van Aerle
- Biosciences, College of Life and Environmental Sciences, University of Exeter , Exeter, EX4 4QD, U.K
- Centre for Environment, Fisheries, and Aquaculture Science (Cefas), Barrack Road, The Nothe, Weymouth, Dorset DT4 8UB, U.K
| | - A Ross Brown
- Biosciences, College of Life and Environmental Sciences, University of Exeter , Exeter, EX4 4QD, U.K
| | - Adam Hargreaves
- AstraZeneca Drug Safety and Metabolism, Alderley Park, Macclesfield, Cheshire SK10 4TF, U.K
- PathCelerate Ltd. The BioHub at Alderley Park, Alderley Edge, Cheshire SK10 4TG, U.K
| | - Russell Huby
- Bioscript, St Peter's Institute , Macclesfield, Cheshire SK11 7HS, U.K
| | - Victoria Cammack
- AstraZeneca Global Environment, Alderley Park, Macclesfield, Cheshire SK10 4TF, U.K
| | - Richard Jackson
- AstraZeneca Drug Safety and Metabolism, Alderley Park, Macclesfield, Cheshire SK10 4TF, U.K
- Institute of Psychiatry, Psychology and Neuroscience, King's College London , De Crespigny Park, Box 63, SE5 8AF, London, U.K
| | - Eduarda M Santos
- Biosciences, College of Life and Environmental Sciences, University of Exeter , Exeter, EX4 4QD, U.K
| | - Charles R Tyler
- Biosciences, College of Life and Environmental Sciences, University of Exeter , Exeter, EX4 4QD, U.K
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12
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Computational analysis of nsSNPs of NPHS1 gene and their effect on protein structural stability. Meta Gene 2017. [DOI: 10.1016/j.mgene.2016.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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13
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Zhang J, Fu H, Xu Y, Niu Y, An X. Hyperoside reduces albuminuria in diabetic nephropathy at the early stage through ameliorating renal damage and podocyte injury. J Nat Med 2016; 70:740-8. [PMID: 27255369 DOI: 10.1007/s11418-016-1007-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 04/30/2016] [Indexed: 02/07/2023]
Abstract
Diabetic nephropathy (DN) is one of the major microvascular complications in diabetes. Podocyte injury such as slit diaphragm effacement is regarded as a determinant in the occurrence and development of albuminuria in DN. In this study, we examined the effect of hyperoside, an active flavonoid glycoside, on proteinuria and renal damage in a streptozotocin-induced DN mouse model at the early stage. The results showed that oral administration of hyperoside (30 mg/kg/day for 4 weeks could significantly decrease urinary microalbumin excretion and glomerular hyperfiltration in DN mice, but did not affect the glucose and lipid metabolism. Periodic acid-Schiff staining and transmission electron microscopy showed that glomerular mesangial matrix expansion and podocyte process effacement in DN mice were significantly improved by hyperoside. Further investigations via immunofluorescence staining, real-time reverse transcription polymerase chain reaction and Western blot analysis showed that the decreased slit diaphragm protein nephrin and podocin mRNA expression and protein levels in DN mice were restored by hyperoside treatment. Collectively, these findings demonstrated that hyperoside could decrease albuminuria at the early stage of DN by ameliorating renal damage and podocyte injury.
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Affiliation(s)
- Jisheng Zhang
- Department of Otorhinolaryngology, Affiliated Hospital of Qingdao University, 266003, Qingdao, China
- Department of Endocrinology, Jiangsu Province Hospital of Chinese Medicine, 210029, Nanjing, China
| | - Haiyan Fu
- Department of Nephrology, Nanfang Hospital, Southern Medical University, 510515, Guangzhou, China
| | - Yan Xu
- Department of Otorhinolaryngology, Affiliated Hospital of Qingdao University, 266003, Qingdao, China
| | - Yunfei Niu
- Department of Bone Molecular Biology, Changhai Hospital, The Second Military University, 200433, Shanghai, China
| | - Xiaofei An
- Department of Endocrinology, Jiangsu Province Hospital of Chinese Medicine, 210029, Nanjing, China.
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Ma Y, Fujimoto M, Watari H, Kimura M, Shimada Y. The renoprotective effect of shichimotsukokato on hypertension-induced renal dysfunction in spontaneously hypertensive rats. J Nat Med 2015; 70:152-62. [DOI: 10.1007/s11418-015-0945-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 10/04/2015] [Indexed: 10/22/2022]
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15
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Kanwar YS. Continuum of historical controversies regarding the structural-functional relationship of the glomerular ultrafiltration unit. Am J Physiol Renal Physiol 2014; 308:F420-4. [PMID: 25503736 DOI: 10.1152/ajprenal.00640.2014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Yashpal S Kanwar
- Departments of Pathology and Medicine, Northwestern University, Chicago, Illinois
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16
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Wang P, Li M, Liu Q, Chen B, Ji Z. Detection of urinary podocytes and nephrin as markers for children with glomerular diseases. Exp Biol Med (Maywood) 2014; 240:169-74. [PMID: 25245074 DOI: 10.1177/1535370214548995] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The purpose of this study was to detect the urinary podocytes and its related protein, nephrin, in the urine of the children with glomerular disease in order to analyze the relationship of the clinical testing with the significance of the glomerular disease. A total of 65 children with nephrotic syndrome were selected for this study. The podocytes and nephrin were detected in the urinary sediment by indirect immunofluorescence, enzyme-linked immunosorbent assay, and Western blotting. The urinary podocytes and nephrin positive rates were 53.8% and 50.8%, respectively, in the children with glomerular disease. The serum total protein and albumin decreased in the podocyte-positive children, while the urine total protein at 24 h, urinary albumin/creatinine ratio, blood urea nitrogen, and serum creatinine were significantly elevated as compared to those of the podocyte-negative patients. Furthermore, the results were the same in the patients with positive nephrin as compared to that of the patients with negative nephrin. The podocyte number and nephrin level were significantly higher in the lupus nephritis group as compared to those of the other groups. Likewise, the podocyte number and nephrin level dramatically increased in the focal segmental glomerulosclerosis group as compared to those of the mesangial proliferative glomerulonephritis and minimal change disease groups. In addition, the podocyte numbers and nephrin expression were significantly higher in severe proteinuria group as compared to those of the mild proteinuria group. The urinary nephrin expression was positively related to podocyte and urinary albumin/creatinine ratio. We concluded that the detection of the urinary podocytes and nephrin could be taken as markers for children with glomerular disease, reflecting the type of the disease. Therefore, this can be used as a noninvasive method to evaluate the severity of the kidney disease in children.
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Affiliation(s)
- Pei Wang
- The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510182, China
| | - Min Li
- The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510182, China
| | - Qicai Liu
- The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510182, China
| | - Bo Chen
- The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510182, China
| | - Zequan Ji
- The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510182, China
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17
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Hulkko J, Patrakka J, Lal M, Tryggvason K, Hultenby K, Wernerson A. Neph1 is reduced in primary focal segmental glomerulosclerosis, minimal change nephrotic syndrome, and corresponding experimental animal models of adriamycin-induced nephropathy and puromycin aminonucleoside nephrosis. NEPHRON EXTRA 2014; 4:146-54. [PMID: 25404935 PMCID: PMC4202611 DOI: 10.1159/000365091] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND/AIMS The transmembrane proteins Neph1 and nephrin form a complex in the slit diaphragm (SD) of podocytes. As recent studies indicate an involvement of this complex in the polymerization of the actin cytoskeleton and proteinuria, we wanted to study the subcellular localization of Neph1 in the normal human kidney and its expression in focal segmental glomerulosclerosis (FSGS), minimal change nephrotic syndrome (MCNS), and the corresponding experimental models of Adriamycin-induced nephropathy (ADR) and puromycin aminonucleoside nephrosis (PAN). All these disorders are characterized by substantial foot process effacement (FPE) and proteinuria. MATERIALS AND METHODS Kidney biopsies from patients with primary FSGS (perihilar type) and MCNS were compared to normal renal tissue. Mouse and rat kidney cortices from days 7 and 14 after Adriamycin injection and days 2 and 4 after puromycin aminonucleoside injection, respectively, were compared to control mouse and rat kidney. Polyclonal antibodies against Neph1 and nephrin were used for immunoelectron microscopy, and semiquantification was performed. RESULTS We localized Neph1 mainly to, and in close proximity to, the SD. Double staining of Neph1 and nephrin showed the proteins to be in close connection in the SD. The total amount of Neph1 in the podocytes was significantly reduced in FSGS, MCNS, ADR, and PAN. The reduction of Neph1 was also seen in areas with and without FPE. Nephrin was reduced in MCNS and PAN but unchanged in FSGS. CONCLUSION With nephrin (but not Neph1) unchanged in FSGS, there might be a disruption of the complex and an involvement of Neph1 in its pathogenesis.
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Affiliation(s)
- Jenny Hulkko
- Department of Clinical Science, Intervention and Technology, Stockholm, Sweden
| | - Jaakko Patrakka
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Mark Lal
- Department of Medical Biochemistry and Biophysics, Stockholm, Sweden
| | - Karl Tryggvason
- Department of Medical Biochemistry and Biophysics, Stockholm, Sweden
| | - Kjell Hultenby
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Annika Wernerson
- Department of Clinical Science, Intervention and Technology, Stockholm, Sweden
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18
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Resveratrol increases nephrin and podocin expression and alleviates renal damage in rats fed a high-fat diet. Nutrients 2014; 6:2619-31. [PMID: 25025298 PMCID: PMC4113760 DOI: 10.3390/nu6072619] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 06/09/2014] [Accepted: 06/27/2014] [Indexed: 11/17/2022] Open
Abstract
Resveratrol is well known for its anti-inflammation and anti-oxidant properties, and has been shown to be effective in alleviating the development of obesity. The purpose of this investigation was to analyze the effect of resveratrol on renal damage in obese rats induced by a high-fat diet (HFD) and its possible mechanisms. Male Sprague-Dawley rats were divided into three groups: control, HFD, and HFD plus resveratrol (treated with 100 mg/kg/day resveratrol). Body weight, serum and urine metabolic parameters, and kidney histology were measured. Meanwhile, the activities of nuclear factor-κB (NF-κB) and superoxide dismutase (SOD), the content of malondialdehyde (MDA), and the protein levels of tumor necrosis factor (TNF-α), monocyte chemotactic protein-1 (MCP-1), nephrin and podocin in kidney were detected. Our work showed that resveratrol alleviated dyslipidemia and renal damage induced by HFD, decreased MDA level and increased SOD activity. Furthermore, the elevated NF-κB activity, increased TNF-α and MCP-1 levels, and reduced expressions of nephrin and podocin induced by HFD were significantly reversed by resveratrol. These results suggest resveratrol could ameliorate renal injury in rats fed a HFD, and the mechanisms are associated with suppressing oxidative stress and NF-κB signaling pathway that in turn up-regulate nephrin and podocin protein expression.
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19
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Behbahan AG, Poorshiri B, Mortazavi F, Khaniani MS, Derakhshan SM. NPHS1 gene mutations in children with Nephrotic Syndrome in northwest Iran. Pak J Biol Sci 2014; 16:882-6. [PMID: 24498843 DOI: 10.3923/pjbs.2013.882.886] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Idiopathic Nephrotic Syndrome (NS) is the prevalent glomerular disease in childhood. It is treated with steroid and according to its response is defined as steroid sensitive NS (SSNS) and steroid resistance NS (SRNS). Mutation in NPHS 1 gene is reported in children with SRNS and few cases of SSNS. The aim of current study is to evaluate NPHS1 gene mutations in idiopathic NS (SSNS and SSRS) in Northwest Iran. In this cross-sectional analytic study 20 children from Azeri population in Iran with idiopathic NS including 10 cases with SRNS (5 male and 5 female) and 10 cases with SSNS (7 male and 3 female) were evaluated for NPHS1 gene mutations. DNA was extracted from peripheral blood and NPHSI gene analysis was performed by PCR and direct sequencing method with the use of standard primers. Mutations in NPHS1 gene occurred in 6 cases of SSNS including 3 heterozygous and 3 homozygous mutations and in 8 cases of SRNS including 5 homozygous, one compound heterozygous and 2 heterozygous mutations. Overall 6 different mutations were detected in NPHS1 gene: one deletion, one insertion, 3 missense and one nonsense mutations. Mutations in exon 4 and 27 were only seen in SRNS patients. Mutations in NPHS1 gene could occur in both SRNS and SSNS patients; however, considering higher incidence of heterozygous mutations in SSNS, the existence of milder phenotype in these cases would be the reason for steroid response.
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Affiliation(s)
- A G Behbahan
- Department of Pediatrics, Pediatrics Health Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - B Poorshiri
- Department of Pediatrics, Pediatrics Health Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - F Mortazavi
- Department of Pediatrics, Pediatrics Health Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - M S Khaniani
- Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - S M Derakhshan
- Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
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20
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Sun H, Schlondorff J, Higgs HN, Pollak MR. Inverted formin 2 regulates actin dynamics by antagonizing Rho/diaphanous-related formin signaling. J Am Soc Nephrol 2013; 24:917-29. [PMID: 23620398 DOI: 10.1681/asn.2012080834] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Mutations in inverted formin 2 INF2 are a common cause of familial FSGS. INF2 interacts with diaphanous-related formins (mDia) and antagonizes mDia-mediated actin polymerization in response to active Rho signaling, suggesting that dysregulation of these pathways may mediate the development of INF2-related FSGS. However, the precise mechanisms by which INF2 regulates actin-dependent podocyte behavior remain largely unknown. Here, we investigated the possible role of INF2 in both lamellipodia-associated actin dynamics and actin-dependent slit diaphragm (SD) protein trafficking by manipulating the expression of INF2 and the activity of Rho/mDia signaling in cultured podocytes. Activation of mDia in the absence of INF2 led to defective formation of lamellipodia and abnormal SD trafficking. Effects of mutations disrupting the INF2-mDia interaction suggested the specificity of the mDia-antagonizing effect of INF2 in maintaining the lamellipodium. Furthermore, we found that SD trafficking requires INF2 interaction with lipid raft components. In summary, INF2 regulates lamellipodial actin dynamics and the trafficking of slit diaphragm proteins by opposing Rho/mDia-mediated actin polymerization. Thus, in podocytes, INF2 appears to be an important modulator of actin-dependent behaviors that are under the control of Rho/mDia signaling.
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Affiliation(s)
- Hua Sun
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA
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21
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Che R, Zhang A. Mechanisms of Glucocorticoid Resistance in Idiopathic Nephrotic Syndrome. ACTA ACUST UNITED AC 2013; 37:360-78. [DOI: 10.1159/000350163] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2013] [Indexed: 11/19/2022]
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22
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Wu D, Wen W, Qi CL, Zhao RX, Lü JH, Zhong CY, Chen YY. Ameliorative effect of berberine on renal damage in rats with diabetes induced by high-fat diet and streptozotocin. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2012; 19:712-718. [PMID: 22483555 DOI: 10.1016/j.phymed.2012.03.003] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 02/03/2012] [Accepted: 03/04/2012] [Indexed: 05/31/2023]
Abstract
Berberine (BBR) is one of the main constituents in Rhizoma coptidis and it has widely been used for the treatment of diabetic nephropathy. The aims of the study were to investigate the effects and mechanism of action of berberine on renal damage in diabetic rats. Diabetes and hyperglycaemia were induced in rats by a high-fat diet and intraperitoneal injection of 40 mg/kg streptozotocin (STZ). Rats were randomly divided into 5 groups, such as i) control rats, ii) untreated diabetic rats iii) 250 mg/kg metformin-treated, iv and v) 100 and 200 mg/kg berberine-treated diabetic rats and treated separately for 8 weeks. The fasting blood glucose, insulin, total cholesterol, triglyceride, glycosylated hemoglobin were measured in rats. Kidneys were isolated at the end of the treatment for histology, Western blot analysis and estimation of malonaldehyde (MDA), superoxide dismutase (SOD) and renal advanced glycation endproducts (AGEs). The results revealed that berberine significantly decreased fasting blood glucose, insulin levels, total cholesterol, triglyceride levels, urinary protein excretion, serum creatinine (Scr) and blood urea nitrogen (BUN) in diabetic rats. The histological examinations revealed amelioration of diabetes-induced glomerular pathological changes following treatment with berberine. In addition, the protein expressions of nephrin and podocin were significantly increased. It seems likely that in rats berberine exerts an ameliorative effect on renal damage in diabetes induced by high-fat diet and streptozotocin. The possible mechanisms for the renoprotective effects of berberine may be related to inhibition of glycosylation and improvement of antioxidation that in turn upregulate the expressions of renal nephrin and podocin.
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Affiliation(s)
- Duo Wu
- Department of Pharmacology, Pharmacy College, Jinan University, Guangzhou 510632, PR China.
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23
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Liu H, Xu H, Shen C, Wu C. Effect of the Best Compatibility of Components in Corni Fructus on WT1 Expression in Glomerular Podocytes of Type 2 Diabetic Rats with Early Nephropathy. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2012; 40:537-49. [DOI: 10.1142/s0192415x12500413] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Our previous studies have shown that the best compatibility of components in Corni Fructus (PC) had a protective effect on vascular endothelial cells. In this study, the effect of PC on WT1 expression in glomerular podocytes and the mechanism of PC on early nephropathy in type 2 diabetic rats have been investigated. Type 2 diabetic rats were generated by high-fat diet combined with intraperitoneal injection of 30 mg/kg streptozotocin (STZ), then fed aminoguanidine (100 mg/kg), glimepiride (0.4 mg/kg), low-dose (60 mg/kg) or high-dose (120 mg/kg) of PC once a day for 12 weeks. Fasting blood glucose (FBG) was examined regularly. Insulin (INS) was measured by a radioimmunoassay. Microalbuminuria (mALB) was measured by an ELISA assay. Urinary creatinine (UCr), blood urea nitrogen (BUN) and N-acetyl-β-D-glucosaminidase (NAG) were measured by colorimetric assays. Renal morphological changes were observed by optical microscopy. The expression index of Wilms tumor 1 (WT1EI) in glomeruli was examined by immunohistochemistry. The results showed that PC led to a decrease in FBG (p < 0.01), NAG (p < 0.05) and mALB (p < 0.05) and an increase in INS (p < 0.01) and WT1EI (p < 0.05) compared to the diabetic group. PC could improve renal damage and greatly reduce the renal morphology score (p < 0.05). These results suggested that PC had the protective effect on early nephropathy in type 2 diabetic rats, which was closely related to the regulation of podocytes.
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Affiliation(s)
- Hong Liu
- College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China
- Library, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China
| | - Huiqing Xu
- College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China
| | - Cunsi Shen
- College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China
| | - Chen Wu
- College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China
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O'Brien LL, Grimaldi M, Kostun Z, Wingert RA, Selleck R, Davidson AJ. Wt1a, Foxc1a, and the Notch mediator Rbpj physically interact and regulate the formation of podocytes in zebrafish. Dev Biol 2011; 358:318-30. [PMID: 21871448 DOI: 10.1016/j.ydbio.2011.08.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2010] [Revised: 08/05/2011] [Accepted: 08/08/2011] [Indexed: 01/02/2023]
Abstract
Podocytes help form the glomerular blood filtration barrier in the kidney and their injury or loss leads to renal disease. The Wilms' tumor suppressor-1 (Wt1) and the FoxC1/2 transcription factors, as well as Notch signaling, have been implicated as important regulators of podocyte fate. It is not known whether these factors work in parallel or sequentially on different gene targets, or as higher-order transcriptional complexes on common genes. Here, we use the zebrafish to demonstrate that embryos treated with morpholinos against wt1a, foxc1a, or the Notch transcriptional mediator rbpj develop fewer podocytes, as determined by wt1b, hey1 and nephrin expression, while embryos deficient in any two of these factors completely lack podocytes. From GST-pull-downs and co-immunoprecipitation experiments we show that Wt1a, Foxc1a, and Rbpj can physically interact with each other, whereas only Rbpj binds to the Notch intracellular domain (NICD). In transactivation assays, combinations of Wt1, FoxC1/2, and NICD synergistically induce the Hey1 promoter, and have additive or repressive effects on the Podocalyxin promoter, depending on dosage. Taken together, these data suggest that Wt1, FoxC1/2, and Notch signaling converge on common target genes where they physically interact to regulate a podocyte-specific gene program. These findings further our understanding of the transcriptional circuitry responsible for podocyte formation and differentiation during kidney development.
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Affiliation(s)
- Lori L O'Brien
- Center for Regenerative Medicine and Department of Medicine, Massachusetts General Hospital, Harvard Medical School and Harvard Stem Cell Institute, Boston, MA 02114, USA
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25
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Motor protein Myo1c is a podocyte protein that facilitates the transport of slit diaphragm protein Neph1 to the podocyte membrane. Mol Cell Biol 2011; 31:2134-50. [PMID: 21402783 DOI: 10.1128/mcb.05051-11] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The podocyte proteins Neph1 and nephrin organize a signaling complex at the podocyte cell membrane that forms the structural framework for a functional glomerular filtration barrier. Mechanisms regulating the movement of these proteins to and from the membrane are currently unknown. This study identifies a novel interaction between Neph1 and the motor protein Myo1c, where Myo1c plays an active role in targeting Neph1 to the podocyte cell membrane. Using in vivo and in vitro experiments, we provide data supporting a direct interaction between Neph1 and Myo1c which is dynamic and actin dependent. Unlike wild-type Myo1c, the membrane localization of Neph1 was significantly reduced in podocytes expressing dominant negative Myo1c. In addition, Neph1 failed to localize at the podocyte cell membrane and cell junctions in Myo1c-depleted podocytes. We further demonstrate that similarly to Neph1, Myo1c also binds nephrin and reduces its localization at the podocyte cell membrane. A functional analysis of Myo1c knockdown cells showed defects in cell migration, as determined by a wound assay. In addition, the ability to form tight junctions was impaired in Myo1c knockdown cells, as determined by transepithelial electric resistance (TER) and bovine serum albumin (BSA) permeability assays. These results identify a novel Myo1c-dependent molecular mechanism that mediates the dynamic organization of Neph1 and nephrin at the slit diaphragm and is critical for podocyte function.
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26
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Etiopathology of chronic tubular, glomerular and renovascular nephropathies: clinical implications. J Transl Med 2011; 9:13. [PMID: 21251296 PMCID: PMC3034700 DOI: 10.1186/1479-5876-9-13] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Accepted: 01/20/2011] [Indexed: 02/06/2023] Open
Abstract
Chronic kidney disease (CKD) comprises a group of pathologies in which the renal excretory function is chronically compromised. Most, but not all, forms of CKD are progressive and irreversible, pathological syndromes that start silently (i.e. no functional alterations are evident), continue through renal dysfunction and ends up in renal failure. At this point, kidney transplant or dialysis (renal replacement therapy, RRT) becomes necessary to prevent death derived from the inability of the kidneys to cleanse the blood and achieve hydroelectrolytic balance. Worldwide, nearly 1.5 million people need RRT, and the incidence of CKD has increased significantly over the last decades. Diabetes and hypertension are among the leading causes of end stage renal disease, although autoimmunity, renal atherosclerosis, certain infections, drugs and toxins, obstruction of the urinary tract, genetic alterations, and other insults may initiate the disease by damaging the glomerular, tubular, vascular or interstitial compartments of the kidneys. In all cases, CKD eventually compromises all these structures and gives rise to a similar phenotype regardless of etiology. This review describes with an integrative approach the pathophysiological process of tubulointerstitial, glomerular and renovascular diseases, and makes emphasis on the key cellular and molecular events involved. It further analyses the key mechanisms leading to a merging phenotype and pathophysiological scenario as etiologically distinct diseases progress. Finally clinical implications and future experimental and therapeutic perspectives are discussed.
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Cai Y, Chen J, Jiang J, Cao W, He L. Zhen-wu-tang, a blended traditional Chinese herbal medicine, ameliorates proteinuria and renal damage of streptozotocin-induced diabetic nephropathy in rats. JOURNAL OF ETHNOPHARMACOLOGY 2010; 131:88-94. [PMID: 20547220 DOI: 10.1016/j.jep.2010.06.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Revised: 05/20/2010] [Accepted: 06/04/2010] [Indexed: 05/29/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Zhen-wu-tang (ZWT) is a blended traditional Chinese medicine specifically used for various kidney diseases. AIM OF THE STUDY The present study is to evaluate the effects of ZWT on diabetic nephropathy and investigate the potential anti-diabetic mechanisms. MATERIALS AND METHODS Streptozotocin (STZ)-induced diabetic rats were orally administrated ZWT (80,320 mg/kg b.w.) once a day, for a period of 12 weeks. Body weight, urinary volume, urine protein and blood biochemical parameters were measured every 3 weeks. At the end of the observation period, kidneys were isolated for histology, angiotensin II content determination, real time PCR and Western blot analyses. RESULTS ZWT (320 mg/kg b.w.) prevented body weight loss, reduced polyurea, urinary protein excretion, serum creatinine and blood urea nitrogen, although it did not alter the hyperglycemia. It ameliorated glomerular hypertrophy and expansion of the mesangial area, swell and effacement of foot process. It also suppressed the increased expression of angiotensin II, nephrin and podocin. CONCLUSIONS Data from this study suggest that ZWT possess a protective effect on renal damage of STZ-induced diabetic nephropathy in rats, by suppressing hyperactivity of renal renin-angiotensin system that turns in to modulate renal nephrin and podocin expressions, thereby protecting podocyte from injury.
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Affiliation(s)
- Yu Cai
- College of Pharmacy, Jinan University, China
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28
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Proteomic analysis of the slit diaphragm complex: CLIC5 is a protein critical for podocyte morphology and function. Kidney Int 2010; 78:868-82. [PMID: 20664558 DOI: 10.1038/ki.2010.212] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Podocytes are morphologically complex cells, the junctions of which form critical elements of the final filtration barrier. Disruption of their foot processes and slit diaphragms occur early in the development of many glomerular diseases. Here, we biochemically purified fractions enriched with slit diaphragm proteins and performed a proteomic analysis to identify new components of this important structure. Several known slit diaphragm proteins were found, such as podocin and nephrin, confirming the validity of the purification scheme. However, proteins on the apical membrane such as podocalyxin were neither enriched nor identified in our analysis. The chloride intracellular channel protein 5 (CLIC5), predominantly expressed in podocytes, was enriched in these fractions and localized in the foot process apical and basal membranes. CLIC5 colocalized and associated with the ezrin/radixin/moesin complex and with podocalyxin in podocytes in vivo. It is important to note that CLIC5(-/-) mice were found to have significantly decreased foot process length, widespread foot process abnormalities, and developed proteinuria. The ezrin/radixin/moesin complex and podocalyxin were significantly decreased in podocytes from CLIC5(-/-) mice. Thus, our study identifies CLIC5 as a new component that is enriched in and necessary for foot process integrity and podocyte function in vivo.
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Koukoulaki M, Goumenos DS. The accumulated experience with the use of mycophenolate mofetil in primary glomerulonephritis. Expert Opin Investig Drugs 2010; 19:673-87. [PMID: 20374037 DOI: 10.1517/13543781003765461] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
IMPORTANCE OF THE FIELD The use of mycophenolate mofetil (MMF) has been extended from renal transplantation to the treatment of glomerulonephritis. MMF has been used in patients with steroid- and ciclosporin A (CsA)-dependent or -resistant idiopathic nephrotic syndrome and in patients with deteriorating renal function or adverse reactions to other drugs. MMF has been also used in patients with membranous and IgA nephropathy after failure of other regimens as well as initial treatment. AREAS COVERED IN THIS REVIEW The rationale of MMF treatment in primary glomerulonephritis is based in its antifibrotic and antiproteinuric effects. The mechanism of action is described; the results of cohort and randomized trials in minimal change disease, focal segmental glomerulosclerosis, idiopathic membranous nephropathy and IgA nephropathy are presented along with the adverse reactions profile and the expert opinion. WHAT THE READER WILL GAIN This is an up-to-date review providing insight on this novel agent that is increasingly used in the therapeutics of primary glomerulonephritis. TAKE HOME MESSAGE Although the results are conflicting, MMF seems to be effective at least in some patients, who do not respond to corticosteroids, ciclosporin or cytotoxic drugs. However, the experience with MMF in primary glomerulonephritis is limited and further research is required in order to establish MMF in the treatment of patients with glomerular disease.
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Affiliation(s)
- Maria Koukoulaki
- University Hospital of Patras, Department of Internal Medicine-Nephrology, Rio-Patra, Greece
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30
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Wegner B, Al-Momany A, Kulak SC, Kozlowski K, Obeidat M, Jahroudi N, Paes J, Berryman M, Ballermann BJ. CLIC5A, a component of the ezrin-podocalyxin complex in glomeruli, is a determinant of podocyte integrity. Am J Physiol Renal Physiol 2010; 298:F1492-503. [PMID: 20335315 DOI: 10.1152/ajprenal.00030.2010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The chloride intracellular channel 5A (CLIC5A) protein, one of two isoforms produced by the CLIC5 gene, was isolated originally as part of a cytoskeletal protein complex containing ezrin from placental microvilli. Whether CLIC5A functions as a bona fide ion channel is controversial. We reported previously that a CLIC5 transcript is enriched approximately 800-fold in human renal glomeruli relative to most other tissues. Therefore, this study sought to explore CLIC5 expression and function in glomeruli. RT-PCR and Western blots show that CLIC5A is the predominant CLIC5 isoform expressed in glomeruli. Confocal immunofluorescence and immunogold electron microscopy reveal high levels of CLIC5A protein in glomerular endothelial cells and podocytes. In podocytes, CLIC5A localizes to the apical plasma membrane of foot processes, similar to the known distribution of podocalyxin and ezrin. Ezrin and podocalyxin colocalize with CLIC5A in glomeruli, and podocalyxin coimmunoprecipitates with CLIC5A from glomerular lysates. In glomeruli of jitterbug (jbg/jbg) mice, which lack the CLIC5A protein, ezrin and phospho-ERM levels in podocytes are markedly lower than in wild-type mice. Transmission electron microscopy reveals patchy broadening and effacement of podocyte foot processes as well as vacuolization of glomerular endothelial cells. These ultrastructural changes are associated with microalbuminuria at baseline and increased susceptibility to adriamycin-induced glomerular injury compared with wild-type mice. Together, the data suggest that CLIC5A is required for the development and/or maintenance of the proper glomerular endothelial cell and podocyte architecture. We postulate that the interaction between podocalyxin and subjacent filamentous actin, which requires ezrin, is compromised in podocytes of CLIC5A-deficient mice, leading to dysfunction under unfavorable genetic or environmental conditions.
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Affiliation(s)
- Binytha Wegner
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
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Abstract
An egg changes dramatically at fertilization. These changes include its developmental potential, its physiology, its gene expression profile, and its cell surface. This review highlights the changes in the cell surface of the egg that occur in response to sperm. These changes include modifications to the extracellular matrix, to the plasma membrane, and to the secretory vesicles whose contents direct many of these events. In some species, these changes occur within minutes of fertilization, and are sufficiently dramatic so that they can be seen by the light microscope. Many of these morphological changes were documented in remarkable detail early in the 1900 s by Ernest Everett Just. A recent conference in honor of his contributions stimulated this overview. We highlight the major cell surface changes that occur in echinoderms, one of Just's preferred research organisms.
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Affiliation(s)
- Gary M Wessel
- Department of Molecular and Cellular Biology, Brown University, Providence, Rhode Island 02912, USA.
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Rochlin K, Yu S, Roy S, Baylies MK. Myoblast fusion: when it takes more to make one. Dev Biol 2009; 341:66-83. [PMID: 19932206 DOI: 10.1016/j.ydbio.2009.10.024] [Citation(s) in RCA: 177] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2009] [Revised: 10/14/2009] [Accepted: 10/14/2009] [Indexed: 01/09/2023]
Abstract
Cell-cell fusion is a crucial and highly regulated event in the genesis of both form and function of many tissues. One particular type of cell fusion, myoblast fusion, is a key cellular process that shapes the formation and repair of muscle. Despite its importance for human health, the mechanisms underlying this process are still not well understood. The purpose of this review is to highlight the recent literature pertaining to myoblast fusion and to focus on a comparison of these studies across several model systems, particularly the fly, zebrafish and mouse. Advances in technical analysis and imaging have allowed identification of new fusion genes and propelled further characterization of previously identified genes in each of these systems. Among the cellular steps identified as critical for myoblast fusion are migration, recognition, adhesion, membrane alignment and membrane pore formation and resolution. Importantly, striking new evidence indicates that orthologous genes govern several of these steps across these species. Taken together, comparisons across three model systems are illuminating a once elusive process, providing exciting new insights and a useful framework of genes and mechanisms.
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Affiliation(s)
- Kate Rochlin
- Program in Developmental Biology, Sloan-Kettering Institute, New York, NY 10065, USA
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Nephrin mutations cause childhood- and adult-onset focal segmental glomerulosclerosis. Kidney Int 2009; 76:1268-76. [PMID: 19812541 DOI: 10.1038/ki.2009.381] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Mutations in the NPHS1 gene cause congenital nephrotic syndrome of the Finnish type presenting before the first 3 months of life. Recently, NPHS1 mutations have also been identified in childhood-onset steroid-resistant nephrotic syndrome and milder courses of disease, but their role in adults with focal segmental glomerulosclerosis remains unknown. Here we developed an in silico scoring matrix to evaluate the pathogenicity of amino-acid substitutions using the biophysical and biochemical difference between wild-type and mutant amino acid, the evolutionary conservation of the amino-acid residue in orthologs, and defined domains, with the addition of contextual information. Mutation analysis was performed in 97 patients from 89 unrelated families, of which 52 presented with steroid-resistant nephrotic syndrome after 18 years of age. Compound heterozygous or homozygous NPHS1 mutations were identified in five familial and seven sporadic cases, including one patient 27 years old at onset of the disease. Substitutions were classified as 'severe' or 'mild' using this in silico approach. Our results suggest an earlier onset of the disease in patients with two 'severe' mutations compared to patients with at least one 'mild' mutation. The finding of mutations in a patient with adult-onset focal segmental glomerulosclerosis indicates that NPHS1 analysis could be considered in patients with later onset of the disease.
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Lennon R, Welsh G, Singh A, Satchell S, Coward R, Tavaré J, Mathieson P, Saleem M. Rosiglitazone enhances glucose uptake in glomerular podocytes using the glucose transporter GLUT1. Diabetologia 2009; 52:1944-52. [PMID: 19533082 PMCID: PMC7614273 DOI: 10.1007/s00125-009-1423-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Accepted: 05/14/2009] [Indexed: 11/26/2022]
Abstract
AIMS/HYPOTHESIS Peroxisome proliferator-activated receptor (PPAR) gamma agonists are used increasingly in the treatment of type 2 diabetes. In the context of renal disease, PPARgamma agonists reduce microalbuminuria in diabetic nephropathy; however, the mechanisms underlying this effect are unknown. Glomerular podocytes are newly characterised insulin-sensitive cells and there is good evidence that they are targeted in diabetic nephropathy. In this study we investigated the functional and molecular effects of the PPARgamma agonist rosiglitazone on human podocytes. METHODS Conditionally immortalised human podocytes were cultured with rosiglitazone and functional effects were measured with glucose-uptake assays. The effect of rosiglitazone on glucose uptake was also measured in 3T3-L1 adipocytes, nephrin-deficient podocytes, human glomerular endothelial cells, proximal tubular cells and podocytes treated with the NEFA palmitate. The role of the glucose transporter GLUT1 was investigated with immunofluorescence and small interfering RNA knockdown and the plasma membrane expression of GLUT1 was determined with bis-mannose photolabelling. RESULTS Rosiglitazone significantly increased glucose uptake in wild-type podocytes and this was associated with translocation of GLUT1 to the plasma membrane. This effect was blocked with GLUT1 small interfering RNA. Nephrin-deficient podocytes, glomerular endothelial cells and proximal tubular cells did not increase glucose uptake in response to either insulin or rosiglitazone. Furthermore, rosiglitazone significantly increased basal and insulin-stimulated glucose uptake when podocytes were treated with the NEFA palmitate. CONCLUSIONS/INTERPRETATION In conclusion, rosiglitazone has a direct and protective effect on glucose uptake in wild-type human podocytes. This represents a novel mechanism by which PPARgamma agonists may improve podocyte function in diabetic nephropathy.
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Affiliation(s)
- R. Lennon
- Academic and Children’s Renal Unit, Paul O’Gorman Lifeline Centre, University of Bristol, Southmead Hospital, Bristol BS10 5NB, UK
| | - G.I. Welsh
- Academic and Children’s Renal Unit, Paul O’Gorman Lifeline Centre, University of Bristol, Southmead Hospital, Bristol BS10 5NB, UK
| | - A. Singh
- Academic and Children’s Renal Unit, Paul O’Gorman Lifeline Centre, University of Bristol, Southmead Hospital, Bristol BS10 5NB, UK
| | - S.C. Satchell
- Academic and Children’s Renal Unit, Paul O’Gorman Lifeline Centre, University of Bristol, Southmead Hospital, Bristol BS10 5NB, UK
| | - R.J. Coward
- Academic and Children’s Renal Unit, Paul O’Gorman Lifeline Centre, University of Bristol, Southmead Hospital, Bristol BS10 5NB, UK
| | - J.M. Tavaré
- Department of Biochemistry, University of Bristol, Bristol, UK
| | - P.W. Mathieson
- Academic and Children’s Renal Unit, Paul O’Gorman Lifeline Centre, University of Bristol, Southmead Hospital, Bristol BS10 5NB, UK
| | - M.A. Saleem
- Academic and Children’s Renal Unit, Paul O’Gorman Lifeline Centre, University of Bristol, Southmead Hospital, Bristol BS10 5NB, UK
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Megremis S, Mitsioni A, Mitsioni AG, Fylaktou I, Kitsiou-Tzelli S, Stefanidis CJ, Kanavakis E, Traeger-Synodinos J. Nucleotide variations in the NPHS2 gene in Greek children with steroid-resistant nephrotic syndrome. Genet Test Mol Biomarkers 2009; 13:249-56. [PMID: 19371226 DOI: 10.1089/gtmb.2008.0083] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Mutations in the NPHS2 gene, encoding podocin, are a major cause of autosomal-recessive steroid-resistant nephrotic syndrome (SRNS) in childhood, accounting for up to 30% of sporadic and 20-40% of familial cases. Among 22 Greek children with a clinical diagnosis of SRNS, mutation analysis was performed in all eight NPHS2 gene exons, using denaturing gradient gel electrophoresis and DNA sequencing. The frequency of all nucleotide variations found in patients was also evaluated in 100 unrelated samples (18-30 years) with no known history of nephrotic disease. Three pathogenic genotypes (R138Q/R138Q, R229Q/A295T, and R168H/R168H) accounted for 3/14 (21%) of sporadic patients; the A295T mutation in exon 8 (c.883G>A) is novel and predicted in silico to be pathogenic. Among the familial cases, a single patient was heterozygous for R229Q. Several known polymorphisms were found, including the in cis variants IVS3-46C>T plus IVS3-21C>T, IVS7+7A>G A and exonic variants S96S (c.288C>T), A318A (c.954T>C), and L346L (c.1038A>G), with allele frequencies comparable to those in other populations. A novel substitution (IVS3-17C>T) was found in two related patients, but in no controls. In conclusion, podocin mutations do not appear to be a major cause of SRNS in Greek children, although the study cohort was small. However, NPHS2 gene analysis could still be considered in Greek SRNS patients to support appropriate management. The present study also contributes potentially useful observations for the clinical management of SRNS patients.
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Affiliation(s)
- Spyridon Megremis
- Medical Genetics, Aghia Sofia Children's Hospital, Athens University, Athens, Greece
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36
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Lennon R, Pons D, Sabin MA, Wei C, Shield JP, Coward RJ, Tavaré JM, Mathieson PW, Saleem MA, Welsh GI. Saturated fatty acids induce insulin resistance in human podocytes: implications for diabetic nephropathy. Nephrol Dial Transplant 2009; 24:3288-96. [PMID: 19556298 PMCID: PMC7614380 DOI: 10.1093/ndt/gfp302] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Cellular insulin resistance is the hallmark of type 2 diabetes and predominantly affects adipose and muscle cells. The saturated free fatty acid palmitate is elevated in insulin-resistant states and may directly contribute to cellular insulin resistance. A spectrum of renal disease is associated with increased markers of insulin resistance, although direct causal mechanisms are not known. In the kidney, glomerular podocytes are novel insulin-sensitive cells that have the ability to rapidly transport glucose. In this study, we tested the hypothesis that palmitate would induce insulin resistance in podocytes. METHODS Conditionally immortalized human podocytes were cultured for up to 24 h with 375-750 muM palmitate. Functional effects on glucose uptake and ceramide production were measured. Gene expression was investigated using a focused gene array, and protein signalling and trafficking were studied with Western blotting and immunofluorescence. RESULTS We found that palmitate blocked insulin-stimulated glucose uptake in human podocytes. This was associated with increased ceramide production, and use of the ceramide inhibitors myriocin and fumonisin B1 partially recovered the insulin sensitivity. At the level of transcription, palmitate downregulated genes associated with several pathways involved in insulin signalling. At the protein level, phosphorylation of the insulin receptor, IRS1 and PKB was reduced and there was impaired translocation of GLUT4 to the cell surface. CONCLUSION This is the first study to demonstrate a direct effect of saturated fatty acids on podocyte function. These findings may represent a novel link between systemic insulin resistance and the development of nephropathy.
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Affiliation(s)
- Rachel Lennon
- Academic and Children's, Renal Unit, Paul O'Gorman Lifeline Centre, University of Bristol, Southmead Hospital, Bristol BS10, UK
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37
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Nyström J, Fierlbeck W, Granqvist A, Kulak SC, Ballermann BJ. A human glomerular SAGE transcriptome database. BMC Nephrol 2009; 10:13. [PMID: 19500374 PMCID: PMC2709617 DOI: 10.1186/1471-2369-10-13] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Accepted: 06/05/2009] [Indexed: 11/10/2022] Open
Abstract
Background To facilitate in the identification of gene products important in regulating renal glomerular structure and function, we have produced an annotated transcriptome database for normal human glomeruli using the SAGE approach. Description The database contains 22,907 unique SAGE tag sequences, with a total tag count of 48,905. For each SAGE tag, the ratio of its frequency in glomeruli relative to that in 115 non-glomerular tissues or cells, a measure of transcript enrichment in glomeruli, was calculated. A total of 133 SAGE tags representing well-characterized transcripts were enriched 10-fold or more in glomeruli compared to other tissues. Comparison of data from this study with a previous human glomerular Sau3A-anchored SAGE library reveals that 47 of the highly enriched transcripts are common to both libraries. Among these are the SAGE tags representing many podocyte-predominant transcripts like WT-1, podocin and synaptopodin. Enrichment of podocyte transcript tags SAGE library indicates that other SAGE tags observed at much higher frequencies in this glomerular compared to non-glomerular SAGE libraries are likely to be glomerulus-predominant. A higher level of mRNA expression for 19 transcripts represented by glomerulus-enriched SAGE tags was verified by RT-PCR comparing glomeruli to lung, liver and spleen. Conclusion The database can be retrieved from, or interrogated online at http://cgap.nci.nih.gov/SAGE. The annotated database is also provided as an additional file with gene identification for 9,022, and matches to the human genome or transcript homologs in other species for 1,433 tags. It should be a useful tool for in silico mining of glomerular gene expression.
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Affiliation(s)
- Jenny Nyström
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.
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38
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Muhonen P, Holthofer H. Epigenetic and microRNA-mediated regulation in diabetes. Nephrol Dial Transplant 2009; 24:1088-96. [PMID: 19145005 PMCID: PMC2658734 DOI: 10.1093/ndt/gfn728] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Pirkko Muhonen
- Centre for BioAnalytical Sciences, Dublin City University, Glasnevin, Dublin 9, Ireland
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39
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Abstract
Congenital nephrotic syndrome (CNS) is a rare kidney disorder characterized by heavy proteinuria, hypoproteinemia, and edema starting soon after birth. The majority of cases are caused by genetic defects in the components of the glomerular filtration barrier, especially nephrin and podocin. CNS may also be a part of a more generalized syndrome or caused by a perinatal infection. Immunosuppressive medication is not helpful in the genetic forms of CNS, and kidney transplantation is the only curative therapy. Before the operation, management of these infants largely depends on the magnitude of proteinuria. In severe cases, daily albumin infusions are required to prevent life-threatening edema. The therapy also includes hypercaloric diet, thyroxin and mineral substitution, prevention of thrombotic episodes, and prompt management of infectious complications. The outcome of CNS patients without major extrarenal manifestations is comparable with other patient groups after kidney transplantation.
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40
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Boini KM, Amann K, Kempe D, Alessi DR, Lang F. Proteinuria in mice expressing PKB/SGK-resistant GSK3. Am J Physiol Renal Physiol 2008; 296:F153-9. [PMID: 18987114 DOI: 10.1152/ajprenal.90398.2008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
SGK1 is critically important for mineralocorticoid/salt-induced glomerular injury. SGK1 inactivates GSK3, which downregulates Snail, a DNA-binding molecule repressing the transcription of nephrin, a protein critically important for the integrity of the glomerular slit membrane. PKB/SGK-dependent GSK regulation is disrupted in mice carrying a mutation, in which the serine in the SGK/PKB-phosphorylation consensus sequence is replaced by alanine. The present study explored whether PKB/SGK-dependent GSK3 regulation influences glomerular proteinuria. Gene-targeted knockin mice with mutated and thus PKB/SGK-resistant GSK3alpha,beta (gsk3(KI)) were compared with their wild-type littermates (gsk3(WT)). gsk3(KI) and gsk3(WT) mice were implanted with DOCA release pellets and offered 1% saline as drinking water for 21 days. Under standard diet, tap water intake and absence of DOCA, urinary flow rate, glomerular filtration rate, and urinary albumin excretion were significantly larger and blood pressure was significantly higher in gsk3(KI) than in gsk3(WT) mice. Within 18 days, DOCA/salt treatment significantly increased fluid intake and urinary flow rate, urinary protein and albumin excretion, and blood pressure in both genotypes but the respective values were significantly higher in gsk3(KI) than in gsk3(WT) mice. Plasma albumin concentration was significantly lower in gsk3(KI) than in gsk3(WT) mice. Proteinuria was abrogated by lowering of blood pressure with alpha(1)-blocker prazosin (1 microg/g body wt) in 8-mo-old mice. According to immunofluorescence, nephrin at 3 and 8 mo and podocin expression at 3 mo were significantly lower in gsk3(KI) than in gsk3(WT) mice. After 18 days, DOCA/salt treatment renal glomerular sclerosis and tubulointerstitial damage were significantly more pronounced in gsk3(KI) than in gsk3(WT) mice. The observations reveal that disruption of PKB/SGK-dependent regulation of GSK3 leads to glomerular injury with proteinuria, which may at least partially be secondary to enhanced blood pressure.
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Affiliation(s)
- Krishna M Boini
- Dept. of Physiology, Univ. of Tübingen, Gmelinstr. 5, D-72076, Tübingen, Germany
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Wagner MC, Rhodes G, Wang E, Pruthi V, Arif E, Saleem MA, Wean SE, Garg P, Verma R, Holzman LB, Gattone V, Molitoris BA, Nihalani D. Ischemic injury to kidney induces glomerular podocyte effacement and dissociation of slit diaphragm proteins Neph1 and ZO-1. J Biol Chem 2008; 283:35579-89. [PMID: 18922801 DOI: 10.1074/jbc.m805507200] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Glomerular injury is often characterized by the effacement of podocytes, loss of slit diaphragms, and proteinuria. Renal ischemia or the loss of blood flow to the kidneys has been widely associated with tubular and endothelial injury but rarely has been shown to induce podocyte damage and disruption of the slit diaphragm. In this study, we have used an in vivo rat ischemic model to demonstrate that renal ischemia induces podocyte effacement with loss of slit diaphragm and proteinuria. Biochemical analysis of the ischemic glomerulus shows that ischemia induces rapid loss of interaction between slit diaphragm junctional proteins Neph1 and ZO-1. To further understand the effect of ischemia on molecular interactions between slit diaphragm proteins, a cell culture model was employed to study the binding between Neph1 and ZO-1. Under physiologic conditions, Neph1 co-localized with ZO-1 at cell-cell contacts in cultured human podocytes. Induction of injury by ATP depletion resulted in rapid loss of Neph1 and ZO-1 binding and redistribution of Neph1 and ZO-1 proteins from cell membrane to the cytoplasm. Recovery resulted in increased Neph1 tyrosine phosphorylation, restoring Neph1 and ZO-1 binding and their localization at the cell membrane. We further demonstrate that tyrosine phosphorylation of Neph1 mediated by Fyn results in significantly increased Neph1 and ZO-1 binding, suggesting a critical role for Neph1 tyrosine phosphorylation in reorganizing the Neph1-ZO-1 complex. This study documents that renal ischemia induces dynamic changes in the molecular interactions between slit diaphragm proteins, leading to podocyte damage and proteinuria.
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Affiliation(s)
- Mark C Wagner
- Department of Medicine, Division of Nephrology, Indiana University, Indianapolis, Indiana 46202, USA
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42
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Lennon R, Singh A, Welsh GI, Coward RJ, Satchell S, Ni L, Mathieson PW, Bakker WW, Saleem MA. Hemopexin induces nephrin-dependent reorganization of the actin cytoskeleton in podocytes. J Am Soc Nephrol 2008; 19:2140-9. [PMID: 18753258 DOI: 10.1681/asn.2007080940] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Hemopexin is an abundant plasma protein that effectively scavenges heme. When infused into rats, hemopexin induces reversible proteinuria, and activated hemopexin is increased in children with minimal change nephrotic syndrome. These observations suggest a role for hemopexin in glomerular disease; in this study, the effects of active hemopexin on human podocytes and glomerular endothelial cells, the two cell types that compose the glomerular filtration barrier, were investigated. Within 30 min of treatment with hemopexin, actin reorganized from stress fibers to cytoplasmic aggregates and membrane ruffles in wild-type podocytes. This did not occur in nephrin-deficient podocytes unless they were transfected with nephrin-expressing plasmids. Furthermore, hemopexin did not affect actin organization in cells that do not express nephrin, specifically human glomerular endothelial cells, fibroblasts, and HEK293 cells. The effects of hemopexin on wild-type podocytes reversed within 4 h and were inhibited by preincubation with human plasma. Treatment with hemopexin activated protein kinase B in both wild-type and nephrin-deficient podocytes but activated RhoA only in wild-type cells. In addition, hemopexin led to a selective increase in the passage of albumin across monolayers of glomerular endothelial cells and to a reduction in glycocalyx. In summary, active hemopexin causes nephrin-dependent remodeling of podocytes and affects permeability of the glomerular filtration barrier by degrading the glycocalyx.
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Affiliation(s)
- Rachel Lennon
- Academic and Children's Renal Unit, University of Bristol, Southmead Hospital, Bristol, United Kingdom BS10 5NB
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Otaki Y, Miyauchi N, Higa M, Takada A, Kuroda T, Gejyo F, Shimizu F, Kawachi H. Dissociation of NEPH1 from nephrin is involved in development of a rat model of focal segmental glomerulosclerosis. Am J Physiol Renal Physiol 2008; 295:F1376-87. [PMID: 18715943 DOI: 10.1152/ajprenal.00075.2008] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Focal segmental glomerulosclerosis (FSGS) is a disease showing severe proteinuria, and the disease progresses to end-stage kidney failure in many cases. However, the pathogenic mechanism of FSGS is not well understood. The slit diaphragm (SD), which bridges the neighboring foot processes of glomerular epithelial cells, is understood to function as a barrier of the glomerular capillary wall. To investigate the role of SD dysfunction in the development of FSGS, we analyzed the expression of SD-associated molecules in rat adriamycin-induced nephropathy, a mimic of FSGS. The staining of the SD molecules nephrin, podocin, and NEPH1 had already shifted to a discontinuous dotlike pattern at the initiation phase of the disease, when neither proteinuria nor any morphological alterations were detected yet. The alteration of NEPH1 expression was the most evident among the molecules examined, and NEPH1 was dissociated from nephrin at the initiation phase. On day 28, when severe proteinuria was detected and sclerotic changes were already observed, alteration of the expressions of nephrin, podocin, and NEPH1 worsened, but no alteration in the expression of other SD-associated molecules or other podocyte molecules was detected. It is postulated that the dissociation of NEPH1 from nephrin initiates proteinuria and that the SD alteration restricted in these molecules plays a critical role in the development of sclerotic changes in FSGS.
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Affiliation(s)
- Yasuhiro Otaki
- Department of Cell Biology, Institute of Nephrology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Niigata, 951-8510, Japan
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Heeringa SF, Vlangos CN, Chernin G, Hinkes B, Gbadegesin R, Liu J, Hoskins BE, Ozaltin F, Hildebrandt F. Thirteen novel NPHS1 mutations in a large cohort of children with congenital nephrotic syndrome. Nephrol Dial Transplant 2008; 23:3527-33. [PMID: 18503012 DOI: 10.1093/ndt/gfn271] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Congenital nephrotic syndrome (CNS) is de- fined as nephrotic syndrome that manifests at birth or within the first 3 months of life. Most patients develop end-stage renal disease (ESRD) within 2 to 3 years of life. CNS of the Finnish-type (CNF) features a rather specific renal histology and is caused by recessive mutations in the NPHS1 gene encoding nephrin, a major structural protein of the glomerular slit-diaphragm. So far, more than 80 different mutations of NPHS1 causing CNF have been published. METHODS Here, we performed mutation analysis of NPHS1 by exon sequencing in a worldwide cohort of 32 children with CNS from 29 different families. RESULTS Sixteen of the 29 families (55%) were found to have two disease-causing alleles in NPHS1. Two additional patients had a single heterozygous mutation in NPHS1. Thirteen of a total of 20 different mutations detected were novel (65%). These were five missense mutations, one nonsense mutation, three deletions, one insertion and three splice-site mutations. CONCLUSION Our data expand the spectrum of known NPHS1 mutations by >15% in a worldwide cohort. Surprisingly, two patients with disease-causing mutations showed a relatively mild phenotype, as one patient had a partial remission with steroid treatment and one patient had normal renal function 1 year after the onset of disease. The increased number of known mutations will facilitate future studies into genotype/phenotype correlations.
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Affiliation(s)
- Saskia F Heeringa
- Department of Pediatrics, University of Michigan, Ann Arbor, MI 48109-5646, USA
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Kim EY, Choi KJ, Dryer SE. Nephrin binds to the COOH terminus of a large-conductance Ca2+-activated K+ channel isoform and regulates its expression on the cell surface. Am J Physiol Renal Physiol 2008; 295:F235-46. [PMID: 18480178 DOI: 10.1152/ajprenal.00140.2008] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We carried out a yeast two-hybrid screen to identify proteins that interact with large-conductance Ca2+-activated K+ (BKCa) channels encoded by the Slo1 gene. Nephrin, an essential adhesion and scaffolding molecule expressed in podocytes, emerged in this screen. The Slo1-nephrin interaction was confirmed by coimmunoprecipitation from the brain and kidney, from HEK-293T cells expressing both proteins, and by glutathione S-transferase pull-down assays. We detected nephrin binding to the Slo1 VEDEC splice variant, which is typically retained in intracellular stores, and to the beta4-subunit. However, we did not detect significant binding of nephrin to the Slo1 QEERL or Slo1 EMVYR splice variants. Coexpression of nephrin with Slo1 VEDEC increased expression of functional BKCa channels on the surface of HEK-293T cells but did not affect steady-state surface expression of the other COOH-terminal Slo1 variants. Nephrin did not affect the kinetics or voltage dependence of channel activation in HEK-293T cells expressing Slo1. Stimulation of Slo1 VEDEC surface expression in HEK-293T cells was also observed by coexpressing a small construct encoding only the distal COOH-terminal domains of nephrin that interact with Slo1. Reduction of endogenous nephrin expression by application of small interfering RNA to differentiated cells of an immortalized podocyte cell line markedly reduced the steady-state surface expression of Slo1 as assessed by electrophysiology and cell-surface biotinylation assays. Nephrin therefore plays a role in organizing the surface expression of ion channel proteins in podocytes and may play a role in outside-in signaling to allow podocytes to adapt to mechanical or neurohumoral stimuli originating in neighboring cells.
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Affiliation(s)
- Eun Young Kim
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204-5001, USA
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46
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Amelioration of anti-cancer agent adriamycin-induced nephrotic syndrome in rats by Wulingsan (Gorei-San), a blended traditional Chinese herbal medicine. Food Chem Toxicol 2008; 46:1452-60. [DOI: 10.1016/j.fct.2007.12.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Revised: 11/28/2007] [Accepted: 12/03/2007] [Indexed: 12/16/2022]
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47
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Johnson RI, Seppa MJ, Cagan RL. The Drosophila CD2AP/CIN85 orthologue Cindr regulates junctions and cytoskeleton dynamics during tissue patterning. ACTA ACUST UNITED AC 2008; 180:1191-204. [PMID: 18362180 PMCID: PMC2290846 DOI: 10.1083/jcb.200706108] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Developing tissues require cells to undergo intricate processes to shift into appropriate niches. This requires a functional connection between adhesion-mediating events at the cell surface and a cytoskeletal reorganization to permit directed movement. A small number of proteins are proposed to link these processes. Here, we identify one candidate, Cindr, the sole Drosophila melanogaster member of the CD2AP/CIN85 family (this family has been previously implicated in a variety of processes). Using D. melanogaster retina, we demonstrate that Cindr links cell surface junctions (E-cadherin) and adhesion (Roughest) with multiple components of the actin cytoskeleton. Reducing cindr activity leads to defects in local cell movement and, consequently, tissue patterning and cell death. Cindr activity is required for normal localization of Drosophila E-cadherin and Roughest, and we show additional physical and functional links to multiple components of the actin cytoskeleton, including the actin-capping proteins capping protein alpha and capping protein beta. Together, these data demonstrate that Cindr is involved in dynamic cell rearrangement in an emerging epithelium.
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Affiliation(s)
- Ruth I Johnson
- Department of Developmental and Regenerative Biology, Mount Sinai Medical School, New York, NY 10029, USA
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48
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Jefferson JA, Shankland SJ, Pichler RH. Proteinuria in diabetic kidney disease: a mechanistic viewpoint. Kidney Int 2008; 74:22-36. [PMID: 18418356 DOI: 10.1038/ki.2008.128] [Citation(s) in RCA: 285] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Proteinuria is the hallmark of diabetic kidney disease (DKD) and is an independent risk factor for both renal disease progression, and cardiovascular disease. Although the characteristic pathological changes in DKD include thickening of the glomerular basement membrane and mesangial expansion, these changes per se do not readily explain how patients develop proteinuria. Recent advances in podocyte and glomerular endothelial cell biology have shifted our focus to also include these cells of the glomerular filtration barrier in the development of proteinuria in DKD. This review describes the pathophysiological mechanisms at a cellular level which explain why patients with DKD develop proteinuria.
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Affiliation(s)
- J A Jefferson
- Division of Nephrology, Department of Medicine, University of Washington School of Medicine, Seattle, Washington 98195, USA.
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49
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50
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Kanwar YS, Danesh FR, Chugh SS. Contribution of proteoglycans towards the integrated functions of renal glomerular capillaries: a historical perspective. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 171:9-13. [PMID: 17591948 PMCID: PMC1941605 DOI: 10.2353/ajpath.2007.070356] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Yashpal S Kanwar
- Northwestern University Medical School, Department of Pathology, Chicago, IL 60611, USA.
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