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Culver SA, Hargett SR, Balugo JLLQ, Gildea JJ, Harris TE, Siragy HM. Nephron specific ATP6AP2 knockout increases urinary excretion of fatty acids and decreases renal cortical megalin expression. Sci Rep 2024; 14:18724. [PMID: 39134597 PMCID: PMC11319469 DOI: 10.1038/s41598-024-69749-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Accepted: 08/08/2024] [Indexed: 08/15/2024] Open
Abstract
ATP6AP2 knockout in the renal nephron impairs receptor-mediated endocytosis, increasing urinary albumin and glucose excretion and impairing weight gain. Nonesterified fatty acids (NEFA) in urine are bound to albumin and reabsorbed in the proximal tubule through receptor-mediated endocytosis by the megalin-cubilin complex. We hypothesized that ATP6AP2 knockout increases urinary NEFA excretion through a reduction in megalin. Ten-week-old male C57BL/6 mice with nephron specific inducible ATP6AP2 knockout and noninduced controls were fed either normal diet (ND 12% fat) or high fat diet (HFD 45% fat) for 6 months. ATP6AP2 knockout significantly increased urine albumin:creatinine ratio in both ND and HFD fed mice while normalized urine NEFA concentration increased 489% and 259% in ND and HFD knockout mice compared to respective controls. Knockout decreased renal cortical megalin mRNA by 47% on ND and 49% on HFD while megalin protein expression decreased by 36% and 44% respectively. At the same time, markers of mTOR activity were increased while autophagy was impaired. Our results indicate that nephron specific ATP6AP2 knockout increases urinary NEFA excretion in the setting of impaired receptor-mediated endocytosis. Further investigation should determine whether ATP6AP2 contributes to obesity related ectopic lipid deposition in the proximal tubule.
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Affiliation(s)
- Silas A Culver
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, P.O. Box 801409, Charlottesville, VA, 22908-1409, USA.
| | - Stefan R Hargett
- Department of Pharmacology, University of Virginia Health System, Charlottesville, USA
| | - Jamie L L Q Balugo
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, P.O. Box 801409, Charlottesville, VA, 22908-1409, USA
| | - John J Gildea
- Department of Pathology, University of Virginia Health System, Charlottesville, USA
| | - Thurl E Harris
- Department of Pharmacology, University of Virginia Health System, Charlottesville, USA
| | - Helmy M Siragy
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, P.O. Box 801409, Charlottesville, VA, 22908-1409, USA
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2
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Faivre A, Bugarski M, Rinaldi A, Sakhi IB, Verissimo T, Legouis D, Rutkowski JM, Correia S, Kaminska M, Dalga D, Malpetti D, Cippa PE, de Seigneux S, Hall AM. Spatiotemporal Landscape of Kidney Tubular Responses to Glomerular Proteinuria. J Am Soc Nephrol 2024; 35:854-869. [PMID: 38652545 PMCID: PMC11230716 DOI: 10.1681/asn.0000000000000357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 04/12/2024] [Indexed: 04/25/2024] Open
Abstract
Key Points
Glomerular proteinuria induces large-scale changes in gene expression along the nephron.Increased protein uptake in the proximal tubule results in axial remodeling and injury.Increased protein delivery to the distal tubule causes dedifferentiation of the epithelium.
Background
Large increases in glomerular protein filtration induce major changes in body homeostasis and are associated with a higher risk of kidney functional decline and cardiovascular disease. We investigated how elevated protein exposure modifies the landscape of tubular function along the entire nephron, to understand the cellular changes that mediate these important clinical phenomena.
Methods
We conducted single-nucleus RNA sequencing, functional intravital imaging, and antibody staining to spatially map transport processes along the mouse kidney tubule. We then delineated how these were altered in a transgenic mouse model of inducible glomerular proteinuria (POD-ATTAC) at 7 and 28 days.
Results
Glomerular proteinuria activated large-scale and pleiotropic changes in gene expression in all major nephron sections. Extension of protein uptake from early (S1) to later (S2) parts of the proximal tubule initially triggered dramatic expansion of a hybrid S1/2 population, followed by injury and failed repair, with the cumulative effect of loss of canonical S2 functions. Proteinuria also induced acute injury in S3. Meanwhile, overflow of luminal proteins to the distal tubule caused transcriptional convergence between specialized regions and generalized dedifferentiation.
Conclusions
Proteinuria modulated cell signaling in tubular epithelia and caused distinct patterns of remodeling and injury in a segment-specific manner.
Podcast
This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/JASN/2024_05_01_ASN0000000000000357.mp3
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Affiliation(s)
- Anna Faivre
- Department of Medicine and Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Milica Bugarski
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Anna Rinaldi
- Laboratories for Translational Research, Ente Ospedaliero Cantonale, Bellinzona, Switzerland
- Division of Nephrology, Department of Medicine, Ente Ospedaliero Cantonale, Lugano, Switzerland
| | - Imene B Sakhi
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Thomas Verissimo
- Department of Medicine and Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - David Legouis
- Department of Medicine and Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
- Division of Intensive Care, Department of Acute Medicine, University Hospital of Geneva, Geneva, Switzerland
| | | | - Sara Correia
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Monika Kaminska
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Delal Dalga
- Department of Medicine and Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Daniele Malpetti
- Istituto Dalle Molle di Studi sull'Intelligenza Artificiale (IDSIA), USI/SUPSI, Lugano, Switzerland
| | - Pietro E Cippa
- Laboratories for Translational Research, Ente Ospedaliero Cantonale, Bellinzona, Switzerland
- Division of Nephrology, Department of Medicine, Ente Ospedaliero Cantonale, Lugano, Switzerland
| | - Sophie de Seigneux
- Department of Medicine and Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
- Department of Medicine, Service of Nephrology, Geneva University Hospitals, Geneva, Switzerland
| | - Andrew M Hall
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
- Department of Nephrology, University Hospital Zurich, Zurich, Switzerland
- Zurich Kidney Center, Zurich, Switzerland
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3
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Wang N, Ren L, Danser AHJ. Vacuolar H +-ATPase in Diabetes, Hypertension, and Atherosclerosis. Microcirculation 2024; 31:e12855. [PMID: 38683673 DOI: 10.1111/micc.12855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 03/29/2024] [Accepted: 04/15/2024] [Indexed: 05/02/2024]
Abstract
Vacuolar H+-ATPase (V-ATPase) is a multisubunit protein complex which, along with its accessory proteins, resides in almost every eukaryotic cell. It acts as a proton pump and as such is responsible for regulating pH in lysosomes, endosomes, and the extracellular space. Moreover, V-ATPase has been implicated in receptor-mediated signaling. Although numerous studies have explored the role of V-ATPase in cancer, osteoporosis, and neurodegenerative diseases, research on its involvement in vascular disease remains limited. Vascular diseases pose significant challenges to human health. This review aimed to shed light on the role of V-ATPase in hypertension and atherosclerosis. Furthermore, given that vascular complications are major complications of diabetes, this review also discusses the pathways through which V-ATPase may contribute to such complications. Beginning with an overview of the structure and function of V-ATPase in hypertension, atherosclerosis, and diabetes, this review ends by exploring the pharmacological potential of targeting V-ATPase.
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Affiliation(s)
- Na Wang
- Division of Vascular Medicine and Pharmacology, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
- Clinical Research Center, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Liwei Ren
- Division of Vascular Medicine and Pharmacology, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
- Department of Pharmacy, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, China
| | - A H Jan Danser
- Division of Vascular Medicine and Pharmacology, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
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4
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Selheim F, Aasebø E, Reikvam H, Bruserud Ø, Hernandez-Valladares M. Monocytic Differentiation of Human Acute Myeloid Leukemia Cells: A Proteomic and Phosphoproteomic Comparison of FAB-M4/M5 Patients with and without Nucleophosmin 1 Mutations. Int J Mol Sci 2024; 25:5080. [PMID: 38791118 PMCID: PMC11121526 DOI: 10.3390/ijms25105080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 04/14/2024] [Accepted: 04/24/2024] [Indexed: 05/26/2024] Open
Abstract
Even though morphological signs of differentiation have a minimal impact on survival after intensive cytotoxic therapy for acute myeloid leukemia (AML), monocytic AML cell differentiation (i.e., classified as French/American/British (FAB) subtypes M4/M5) is associated with a different responsiveness both to Bcl-2 inhibition (decreased responsiveness) and possibly also bromodomain inhibition (increased responsiveness). FAB-M4/M5 patients are heterogeneous with regard to genetic abnormalities, even though monocytic differentiation is common for patients with Nucleophosmin 1 (NPM1) insertions/mutations; to further study the heterogeneity of FAB-M4/M5 patients we did a proteomic and phosphoproteomic comparison of FAB-M4/M5 patients with (n = 13) and without (n = 12) NPM1 mutations. The proteomic profile of NPM1-mutated FAB-M4/M5 patients was characterized by increased levels of proteins involved in the regulation of endocytosis/vesicle trafficking/organellar communication. In contrast, AML cells without NPM1 mutations were characterized by increased levels of several proteins involved in the regulation of cytoplasmic translation, including a large number of ribosomal proteins. The phosphoproteomic differences between the two groups were less extensive but reflected similar differences. To conclude, even though FAB classification/monocytic differentiation are associated with differences in responsiveness to new targeted therapies (e.g., Bcl-2 inhibition), our results shows that FAB-M4/M5 patients are heterogeneous with regard to important biological characteristics of the leukemic cells.
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Affiliation(s)
- Frode Selheim
- Proteomics Unit of University of Bergen (PROBE), University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway
| | - Elise Aasebø
- Acute Leukemia Research Group, Department of Clinical Science, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway; (E.A.); (H.R.); (Ø.B.)
| | - Håkon Reikvam
- Acute Leukemia Research Group, Department of Clinical Science, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway; (E.A.); (H.R.); (Ø.B.)
- Section for Hematology, Department of Medicine, Haukeland University Hospital, 5009 Bergen, Norway
| | - Øystein Bruserud
- Acute Leukemia Research Group, Department of Clinical Science, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway; (E.A.); (H.R.); (Ø.B.)
- Section for Hematology, Department of Medicine, Haukeland University Hospital, 5009 Bergen, Norway
| | - Maria Hernandez-Valladares
- Proteomics Unit of University of Bergen (PROBE), University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway
- Department of Physical Chemistry, University of Granada, Avenida de la Fuente Nueva S/N, 18071 Granada, Spain
- Instituto de Investigación Biosanitaria ibs.GRANADA, 18012 Granada, Spain
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McClelland C, Holland OJ, Shrestha N, Jukes CL, Brandon AE, Cuffe JSM, Perkins AV, McAinch AJ, Hryciw DH. Maternal Diet High in Linoleic Acid Alters Renal Branching Morphogenesis and mTOR/AKT Signalling Genes in Rat Fetal Kidneys. Int J Mol Sci 2024; 25:4688. [PMID: 38731907 PMCID: PMC11083378 DOI: 10.3390/ijms25094688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 04/18/2024] [Accepted: 04/22/2024] [Indexed: 05/13/2024] Open
Abstract
Linoleic acid (LA), an n-6 polyunsaturated fatty acid (PUFA), is obtained from the maternal diet during pregnancy, and is essential for normal fetal growth and development. A maternal high-LA (HLA) diet alters maternal and offspring fatty acids, maternal leptin and male/female ratio at embryonic (E) day 20 (E20). We investigated the effects of an HLA diet on embryonic offspring renal branching morphogenesis, leptin signalling, megalin signalling and angiogenesis gene expression. Female Wistar Kyoto rats were fed low-LA (LLA; 1.44% energy from LA) or high-LA (HLA; 6.21% energy from LA) diets during pregnancy and gestation/lactation. Offspring were sacrificed and mRNA from kidneys was analysed by real-time PCR. Maternal HLA decreased the targets involved in branching morphogenesis Ret and Gdnf in offspring, independent of sex. Furthermore, downstream targets of megalin, namely mTOR, Akt3 and Prkab2, were reduced in offspring from mothers consuming an HLA diet, independent of sex. There was a trend of an increase in the branching morphogenesis target Gfra1 in females (p = 0.0517). These findings suggest that an HLA diet during pregnancy may lead to altered renal function in offspring. Future research should investigate the effects an HLA diet has on offspring kidney function in adolescence and adulthood.
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Affiliation(s)
- Connie McClelland
- School of Pharmacy and Medical Science, Griffith University, Southport, QLD 4222, Australia; (C.M.); (O.J.H.); (N.S.); (A.V.P.)
| | - Olivia J. Holland
- School of Pharmacy and Medical Science, Griffith University, Southport, QLD 4222, Australia; (C.M.); (O.J.H.); (N.S.); (A.V.P.)
- Women’s Newborn and Childrens Services, Gold Coast Hospital and Health Service, Southport, QLD 4215, Australia
| | - Nirajan Shrestha
- School of Pharmacy and Medical Science, Griffith University, Southport, QLD 4222, Australia; (C.M.); (O.J.H.); (N.S.); (A.V.P.)
| | - Claire L. Jukes
- School of Environment and Science, Griffith University, Nathan, QLD 4111, Australia; (C.L.J.); (A.E.B.)
| | - Anna E. Brandon
- School of Environment and Science, Griffith University, Nathan, QLD 4111, Australia; (C.L.J.); (A.E.B.)
| | - James S. M. Cuffe
- School of Biomedical Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia;
| | - Anthony V. Perkins
- School of Pharmacy and Medical Science, Griffith University, Southport, QLD 4222, Australia; (C.M.); (O.J.H.); (N.S.); (A.V.P.)
- School of Health, University of Sunshine Coast, Sippy Downs, QLD 4556, Australia
| | - Andrew J. McAinch
- Institute for Health and Sport, Victoria University, Melbourne, VIC 3011, Australia
- Australian Institute for Musculoskeletal Science (AIMSS), Victoria University, St. Albans, VIC 3021, Australia
| | - Deanne H. Hryciw
- Women’s Newborn and Childrens Services, Gold Coast Hospital and Health Service, Southport, QLD 4215, Australia
- Griffith Institute of Drug Discovery, Griffith University, Nathan, QLD 4111, Australia
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6
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Christer S, Simons M. Lysosomal cystine accumulation activates mTOR signaling in cystinosis: are mTOR inhibitors the cure? Kidney Int 2024; 105:656-658. [PMID: 38519228 DOI: 10.1016/j.kint.2023.11.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 11/01/2023] [Indexed: 03/24/2024]
Affiliation(s)
- Salómon Christer
- Nephrogenetics Unit, Institute of Human Genetics, University Hospital Heidelberg, Heidelberg, Germany
| | - Matias Simons
- Nephrogenetics Unit, Institute of Human Genetics, University Hospital Heidelberg, Heidelberg, Germany.
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7
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Chrysopoulou M, Rinschen MM. Metabolic Rewiring and Communication: An Integrative View of Kidney Proximal Tubule Function. Annu Rev Physiol 2024; 86:405-427. [PMID: 38012048 DOI: 10.1146/annurev-physiol-042222-024724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
The kidney proximal tubule is a key organ for human metabolism. The kidney responds to stress with altered metabolite transformation and perturbed metabolic pathways, an ultimate cause for kidney disease. Here, we review the proximal tubule's metabolic function through an integrative view of transport, metabolism, and function, and embed it in the context of metabolome-wide data-driven research. Function (filtration, transport, secretion, and reabsorption), metabolite transformation, and metabolite signaling determine kidney metabolic rewiring in disease. Energy metabolism and substrates for key metabolic pathways are orchestrated by metabolite sensors. Given the importance of renal function for the inner milieu, we also review metabolic communication routes with other organs. Exciting research opportunities exist to understand metabolic perturbation of kidney and proximal tubule function, for example, in hypertension-associated kidney disease. We argue that, based on the integrative view outlined here, kidney diseases without genetic cause should be approached scientifically as metabolic diseases.
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Affiliation(s)
| | - Markus M Rinschen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark;
- III. Department of Medicine and Hamburg Center for Kidney Health, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Aarhus Institute of Advanced Studies, Aarhus University, Aarhus, Denmark
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8
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Peres RAS, Peruchetti DB, Silva-Aguiar RP, Teixeira DE, Gomes CP, Takiya CM, Pinheiro AAS, Caruso-Neves C. Rapamycin treatment induces tubular proteinuria: role of megalin-mediated protein reabsorption. Front Pharmacol 2023; 14:1194816. [PMID: 37484026 PMCID: PMC10359992 DOI: 10.3389/fphar.2023.1194816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 06/27/2023] [Indexed: 07/25/2023] Open
Abstract
Introduction: Rapamycin is an immunosuppressor that acts by inhibiting the serine/threonine kinase mechanistic target of rapamycin complex 1. Therapeutic use of rapamycin is limited by its adverse effects. Proteinuria is an important marker of kidney damage and a risk factor for kidney diseases progression and has been reported in patients and animal models treated with rapamycin. However, the mechanism underlying proteinuria induced by rapamycin is still an open matter. In this work, we investigated the effects of rapamycin on parameters of renal function and structure and on protein handling by proximal tubule epithelial cells (PTECs). Methods: Healthy BALB/c mice were treated with 1.5 mg/kg rapamycin by oral gavage for 1, 3, or 7 days. At the end of each treatment, the animals were kept in metabolic cages and renal function and structural parameters were analyzed. LLC-PK1 cell line was used as a model of PTECs to test specific effect of rapamycin. Results: Rapamycin treatment did not change parameters of glomerular structure and function. Conversely, there was a transient increase in 24-h proteinuria, urinary protein to creatinine ratio (UPCr), and albuminuria in the groups treated with rapamycin. In accordance with these findings, rapamycin treatment decreased albumin-fluorescein isothiocyanate uptake in the renal cortex. This effect was associated with reduced brush border expression and impaired subcellular distribution of megalin in PTECs. The effect of rapamycin seems to be specific for albumin endocytosis machinery because it did not modify renal sodium handling or (Na++K+)ATPase activity in BALB/c mice and in the LLC-PK1 cell line. A positive Pearson correlation was found between megalin expression and albumin uptake while an inverse correlation was shown between albumin uptake and UPCr or 24-h proteinuria. Despite its effect on albumin handling in PTECs, rapamycin treatment did not induce tubular injury measured by interstitial space and collagen deposition. Conclusion: These findings suggest that proteinuria induced by rapamycin could have a tubular rather than a glomerular origin. This effect involves a specific change in protein endocytosis machinery. Our results open new perspectives on understanding the undesired effect of proteinuria generated by rapamycin.
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Affiliation(s)
- Rodrigo A. S. Peres
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Diogo B. Peruchetti
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Rodrigo P. Silva-Aguiar
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Douglas E. Teixeira
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Carlos P. Gomes
- Clementino Fraga Filho University Hospital, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- School of Medicine and Surgery, Federal University of the State of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Christina M. Takiya
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ana Acacia S. Pinheiro
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Rio de Janeiro Innovation Network in Nanosystems for Health-NanoSAÚDE/FAPERJ, Rio de Janeiro, Brazil
| | - Celso Caruso-Neves
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Rio de Janeiro Innovation Network in Nanosystems for Health-NanoSAÚDE/FAPERJ, Rio de Janeiro, Brazil
- National Institute of Science and Technology for Regenerative Medicine, Rio de Janeiro, Brazil
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9
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Francis D, Burguete AS, Ghabrial AS. Regulation of Archease by the mTOR-vATPase axis. Development 2022; 149:dev200908. [PMID: 36111596 PMCID: PMC9641670 DOI: 10.1242/dev.200908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 08/23/2022] [Indexed: 01/19/2023]
Abstract
Larval terminal cells of the Drosophila tracheal system generate extensive branched tubes, requiring a huge increase in apical membrane. We discovered that terminal cells compromised for apical membrane expansion - mTOR-vATPase axis and apical polarity mutants - were invaded by the neighboring stalk cell. The invading cell grows and branches, replacing the original single intercellular junction between stalk and terminal cell with multiple intercellular junctions. Here, we characterize disjointed, a mutation in the same phenotypic class. We find that disjointed encodes Drosophila Archease, which is required for the RNA ligase (RtcB) function that is essential for tRNA maturation and for endoplasmic reticulum stress-regulated nonconventional splicing of Xbp1 mRNA. We show that the steady-state subcellular localization of Archease is principally nuclear and dependent upon TOR-vATPase activity. In tracheal cells mutant for Rheb or vATPase loci, Archease localization shifted dramatically from nucleus to cytoplasm. Further, we found that blocking tRNA maturation by knockdown of tRNAseZ also induced compensatory branching. Taken together, these data suggest that the TOR-vATPase axis promotes apical membrane growth in part through nuclear localization of Archease, where Archease is required for tRNA maturation.
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Affiliation(s)
- Deanne Francis
- College of Public Health, Medical and Veterinary Sciences, Division of Tropical Health and Medicine, Department of Biomedicine and Molecular and Cell Biology, James Cook University, Douglas, QLD 4811, Australia
| | - Alondra S. Burguete
- Department of Biomedicine and Molecular and Cell Biology, The Motor Neuron Center, Columbia University Medical Center, VP&S 5th floor, New York, NY 10032, USA
| | - Amin S. Ghabrial
- Department of Pathology and Cell Biology, Columbia University Medical Center, 630 168th Street, Vagellos Physicians and Surgeons 14-401L, New York, NY 10032, USA
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10
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Elsakka EGE, Mokhtar MM, Hegazy M, Ismail A, Doghish AS. Megalin, a multi-ligand endocytic receptor, and its participation in renal function and diseases: A review. Life Sci 2022; 308:120923. [PMID: 36049529 DOI: 10.1016/j.lfs.2022.120923] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/13/2022] [Accepted: 08/26/2022] [Indexed: 11/16/2022]
Abstract
The endocytosis mechanism is a complicated system that is essential for cell signaling and survival. Megalin, a membrane-associated endocytic receptor, and its related proteins such as cubilin, the neonatal Fc receptor for IgG, and NaPi-IIa are important in receptors-mediated endocytosis. Physiologically, megalin uptakes plasma vitamins and proteins from primary urine, preventing their loss. It also facilitates tubular retrieval of solutes and endogenous components that may be involved in modulation and recovery from kidney injuries. Moreover, megalin is responsible for endocytosis of xenobiotics and drugs in renal tubules, increasing their half-life and/or their toxicity. Fluctuations in megalin expression and/or functionality due to changes in its regulatory mechanisms are associated with some sort of kidney injury. Also, it's an important component of several pathological conditions, including diabetic nephropathy and Dent disease. Thus, exploring the fundamental role of megalin in the kidney might help in the protection and/or treatment of multiple kidney-related diseases. Hence, this review aimed to explore the physiological roles of megalin in the kidney and their implications for kidney-related injuries.
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Affiliation(s)
- Elsayed G E Elsakka
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy (Boys), Al-Azhar University, Nasr City 11231, Cairo, Egypt.
| | - Mahmoud Mohamed Mokhtar
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy (Boys), Al-Azhar University, Nasr City 11231, Cairo, Egypt
| | - Maghawry Hegazy
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy (Boys), Al-Azhar University, Nasr City 11231, Cairo, Egypt
| | - Ahmed Ismail
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy (Boys), Al-Azhar University, Nasr City 11231, Cairo, Egypt
| | - Ahmed S Doghish
- Department of Biochemistry, Faculty of Pharmacy, Badr University in Cairo (BUC), Badr City, Cairo 11829, Egypt.
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11
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Direct control of lysosomal catabolic activity by mTORC1 through regulation of V-ATPase assembly. Nat Commun 2022; 13:4848. [PMID: 35977928 PMCID: PMC9385660 DOI: 10.1038/s41467-022-32515-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 08/03/2022] [Indexed: 12/15/2022] Open
Abstract
Mammalian cells can acquire exogenous amino acids through endocytosis and lysosomal catabolism of extracellular proteins. In amino acid-replete environments, nutritional utilization of extracellular proteins is suppressed by the amino acid sensor mechanistic target of rapamycin complex 1 (mTORC1) through an unknown process. Here, we show that mTORC1 blocks lysosomal degradation of extracellular proteins by suppressing V-ATPase-mediated acidification of lysosomes. When mTORC1 is active, peripheral V-ATPase V1 domains reside in the cytosol where they are stabilized by association with the chaperonin TRiC. Consequently, most lysosomes display low catabolic activity. When mTORC1 activity declines, V-ATPase V1 domains move to membrane-integral V-ATPase Vo domains at lysosomes to assemble active proton pumps. The resulting drop in luminal pH increases protease activity and degradation of protein contents throughout the lysosomal population. These results uncover a principle by which cells rapidly respond to changes in their nutrient environment by mobilizing the latent catabolic capacity of lysosomes. mTORC1 blocks lysosomal nutrient generation. Here, the authors show that mTORC1 inactivation triggers V-ATPase assembly, which rapidly initiates lysosomal acidification and degradation of protein contents throughout the lysosomal population.
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12
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Dow JAT, Simons M, Romero MF. Drosophila melanogaster: a simple genetic model of kidney structure, function and disease. Nat Rev Nephrol 2022; 18:417-434. [PMID: 35411063 DOI: 10.1038/s41581-022-00561-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2022] [Indexed: 12/27/2022]
Abstract
Although the genetic basis of many kidney diseases is being rapidly elucidated, their experimental study remains problematic owing to the lack of suitable models. The fruitfly Drosophila melanogaster provides a rapid, ethical and cost-effective model system of the kidney. The unique advantages of D. melanogaster include ease and low cost of maintenance, comprehensive availability of genetic mutants and powerful transgenic technologies, and less onerous regulation, as compared with mammalian systems. Renal and excretory functions in D. melanogaster reside in three main tissues - the transporting renal (Malpighian) tubules, the reabsorptive hindgut and the endocytic nephrocytes. Tubules contain multiple cell types and regions and generate a primary urine by transcellular transport rather than filtration, which is then subjected to selective reabsorption in the hindgut. By contrast, the nephrocytes are specialized for uptake of macromolecules and equipped with a filtering slit diaphragm resembling that of podocytes. Many genes with key roles in the human kidney have D. melanogaster orthologues that are enriched and functionally relevant in fly renal tissues. This similarity has allowed investigations of epithelial transport, kidney stone formation and podocyte and proximal tubule function. Furthermore, a range of unique quantitative phenotypes are available to measure function in both wild type and disease-modelling flies.
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Affiliation(s)
- Julian A T Dow
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
| | - Matias Simons
- INSERM UMR1163, Laboratory of Epithelial Biology and Disease, Imagine Institute, Université de Paris, Hôpital Necker-Enfants Malades, Paris, France
- Institute of Human Genetics, University Hospital Heidelberg, Heidelberg, Germany
| | - Michael F Romero
- Department of Physiology and Biomedical Engineering, Division of Nephrology and Hypertension, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
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13
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Molitoris BA, Sandoval RM, Yadav SPS, Wagner MC. Albumin Uptake and Processing by the Proximal Tubule: Physiologic, Pathologic and Therapeutic Implications. Physiol Rev 2022; 102:1625-1667. [PMID: 35378997 PMCID: PMC9255719 DOI: 10.1152/physrev.00014.2021] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
For nearly 50 years the proximal tubule (PT) has been known to reabsorb, process, and either catabolize or transcytose albumin from the glomerular filtrate. Innovative techniques and approaches have provided insights into these processes. Several genetic diseases, nonselective PT cell defects, chronic kidney disease (CKD), and acute PT injury lead to significant albuminuria, reaching nephrotic range. Albumin is also known to stimulate PT injury cascades. Thus, the mechanisms of albumin reabsorption, catabolism, and transcytosis are being reexamined with the use of techniques that allow for novel molecular and cellular discoveries. Megalin, a scavenger receptor, cubilin, amnionless, and Dab2 form a nonselective multireceptor complex that mediates albumin binding and uptake and directs proteins for lysosomal degradation after endocytosis. Albumin transcytosis is mediated by a pH-dependent binding affinity to the neonatal Fc receptor (FcRn) in the endosomal compartments. This reclamation pathway rescues albumin from urinary losses and cellular catabolism, extending its serum half-life. Albumin that has been altered by oxidation, glycation, or carbamylation or because of other bound ligands that do not bind to FcRn traffics to the lysosome. This molecular sorting mechanism reclaims physiological albumin and eliminates potentially toxic albumin. The clinical importance of PT albumin metabolism has also increased as albumin is now being used to bind therapeutic agents to extend their half-life and minimize filtration and kidney injury. The purpose of this review is to update and integrate evolving information regarding the reabsorption and processing of albumin by proximal tubule cells including discussion of genetic disorders and therapeutic considerations.
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Affiliation(s)
- Bruce A. Molitoris
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States
- Dept.of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Ruben M. Sandoval
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Shiv Pratap S. Yadav
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Mark C. Wagner
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States
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14
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Kozyraki R, Verroust P, Cases O. Cubilin, the intrinsic factor-vitamin B12 receptor. VITAMINS AND HORMONES 2022; 119:65-119. [PMID: 35337634 DOI: 10.1016/bs.vh.2022.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Cubilin (CUBN), the intrinsic factor-vitamin B12 receptor is a large endocytic protein involved in various physiological functions: vitamin B12 uptake in the gut; reabsorption of albumin and maturation of vitamin D in the kidney; nutrient delivery during embryonic development. Cubilin is an atypical receptor, peripherally associated to the plasma membrane. The transmembrane proteins amnionless (AMN) and Lrp2/Megalin are the currently known molecular partners contributing to plasma membrane transport and internalization of Cubilin. The role of Cubilin/Amn complex in the handling of vitamin B12 in health and disease has extensively been studied and so is the role of the Cubilin-Lrp2 tandem in renal pathophysiology. Accumulating evidence strongly supports a role of Cubilin in some developmental defects including impaired closure of the neural tube. Are these defects primarily caused by the dysfunction of a specific Cubilin ligand or are they secondary to impaired vitamin B12 or protein uptake? We will present the established Cubilin functions, discuss the developmental data and provide an overview of the emerging implications of Cubilin in the field of cardiovascular disease and cancer pathogenesis.
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Affiliation(s)
- Renata Kozyraki
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, Paris, France.
| | - Pierre Verroust
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, Paris, France
| | - Olivier Cases
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, Paris, France
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15
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Atienza-Manuel A, Castillo-Mancho V, De Renzis S, Culi J, Ruiz-Gómez M. Endocytosis mediated by an atypical CUBAM complex modulates slit diaphragm dynamics in nephrocytes. Development 2021; 148:272711. [PMID: 34738617 PMCID: PMC8710305 DOI: 10.1242/dev.199894] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 10/22/2021] [Indexed: 01/14/2023]
Abstract
The vertebrate endocytic receptor CUBAM, consisting of three cubilin monomers complexed with a single amnionless molecule, plays a major role in protein reabsorption in the renal proximal tubule. Here, we show that Drosophila CUBAM is a tripartite complex composed of Amnionless and two cubilin paralogues, Cubilin and Cubilin2, and that it is required for nephrocyte slit diaphragm (SD) dynamics. Loss of CUBAM-mediated endocytosis induces dramatic morphological changes in nephrocytes and promotes enlarged ingressions of the external membrane and SD mislocalisation. These phenotypes result in part from an imbalance between endocytosis, which is strongly impaired in CUBAM mutants, and exocytosis in these highly active cells. Of note, rescuing receptor-mediated endocytosis by Megalin/LRP2 or Rab5 expression only partially restores SD positioning in CUBAM mutants, suggesting a specific requirement of CUBAM in SD degradation and/or recycling. This finding and the reported expression of CUBAM in podocytes suggest a possible unexpected conserved role for this endocytic receptor in vertebrate SD remodelling. Summary: A genetic study revealing that endocytosis mediated by an atypical CUBAM endocytic receptor, composed of Amnionless and two Cubilin paralogues, regulates slit diaphragm remodelling in Drosophila nephrocytes.
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Affiliation(s)
- Alexandra Atienza-Manuel
- Centro de Biología Molecular Severo Ochoa, CSIC and UAM, Nicolás Cabrera 1, Cantoblanco 28049, Madrid, Spain
| | - Vicente Castillo-Mancho
- Centro de Biología Molecular Severo Ochoa, CSIC and UAM, Nicolás Cabrera 1, Cantoblanco 28049, Madrid, Spain
| | - Stefano De Renzis
- European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Joaquim Culi
- Centro de Biología Molecular Severo Ochoa, CSIC and UAM, Nicolás Cabrera 1, Cantoblanco 28049, Madrid, Spain
| | - Mar Ruiz-Gómez
- Centro de Biología Molecular Severo Ochoa, CSIC and UAM, Nicolás Cabrera 1, Cantoblanco 28049, Madrid, Spain
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16
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Grahammer F, Huber TB, Artunc F. Role of mTOR Signaling for Tubular Function and Disease. Physiology (Bethesda) 2021; 36:350-358. [PMID: 34514872 DOI: 10.1152/physiol.00021.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR) forms two distinct intracellular multiprotein complexes that control a multitude of intracellular processes linked to metabolism, proliferation, actin cytoskeleton, and survival. Recent studies have identified the importance of these complexes for transport regulation of ions and nutrients along the entire nephron. First reports could link altered activity of these complexes to certain disease entities, i.e. diabetic nephropathy, acute kidney injury or hyperkalemia.
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Affiliation(s)
- Florian Grahammer
- Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tobias B Huber
- Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ferruh Artunc
- Department of Internal Medicine, Division of Endocrinology, Diabetology, and Nephrology, University Hospital Tübingen, Tübingen, Germany.,Institute of Diabetes Research and Metabolic Diseases, Helmholtz Center Munich, University Tübingen, Tübingen, Germany.,German Center for Diabetes Research, University Tübingen, Tübingen, Germany
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17
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Hoffmann N, Peters J. Functions of the (pro)renin receptor (Atp6ap2) at molecular and system levels: pathological implications in hypertension, renal and brain development, inflammation, and fibrosis. Pharmacol Res 2021; 173:105922. [PMID: 34607004 DOI: 10.1016/j.phrs.2021.105922] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 09/16/2021] [Accepted: 09/29/2021] [Indexed: 12/13/2022]
Abstract
The (pro)renin receptor [(P)RR, Atp6ap2] was initially discovered as a membrane-bound binding partner of prorenin and renin. A soluble (P)RR has additional paracrine effects and is involved in metabolic syndrome and kidney damage. Meanwhile it is clear that most of the effects of the (P)RR are independent of prorenin. In the kidney, (P)RR plays an important role in renal dysfunction by activating proinflammatory and profibrotic molecules. In the brain, (P)RR is expressed in cardiovascular regulatory nuclei and is linked to hypertension. (P)RR is known to be an essential component of the v-ATPase as a key accessory protein and plays an important role in kidney, brain and heart via regulating the pH of the extracellular space and intracellular compartments. V-ATPase and (P)RR together act on WNT and mTOR signalling pathways, which are responsible for cellular homeostasis and autophagy. (P)RR through its role in v-ATPase assembly and function is also important for fast recycling endocytosis by megalin. In the kidney, megalin together with v-ATPase and (P)RR is crucial for endocytic uptake of components of the RAS and their intracellular processing. In the brain, (P)RR, v-ATPases and megalin are important regulators both during development and in the adult. All three proteins are associated with diseases such as XLMR, XMRE, X-linked parkinsonism and epilepsy, cognitive disorders with Parkinsonism, spasticity, intellectual disability, and Alzheimer's Disease which are characterized by impaired neuronal function and/or neuronal loss. The present review focusses on the relevant effects of Atp6ap2 without assigning them necessarily to the RAS. Mechanistically, many effects can be well explained by the role of Atp6ap2 for v-ATPase assembly and function. Furthermore, application of a soluble (P)RR analogue as new therapeutic option is discussed.
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Affiliation(s)
- Nadin Hoffmann
- Institute of Physiology, University Medicine Greifswald, Friedrich-Ludwig-Jahn-Str. 15A, 17475, Greifswald, Germany
| | - Jörg Peters
- Institute of Physiology, University Medicine Greifswald, Friedrich-Ludwig-Jahn-Str. 15A, 17475, Greifswald, Germany.
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18
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Sun-Wada GH, Tabata H, Wada Y. Vacuolar-type proton ATPase is required for maintenance of apicobasal polarity of embryonic visceral endoderm. Sci Rep 2021; 11:19355. [PMID: 34588579 PMCID: PMC8481250 DOI: 10.1038/s41598-021-98952-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 09/17/2021] [Indexed: 12/29/2022] Open
Abstract
The endocytic compartments keep their interior acidic through the inward flow of protons and anions from the cytosol. Acidification is mediated by a proton pump known as vacuolar-type ATPase (V-ATPase) and transporters conferring anion conductance to the organellar membrane. In this study, we analysed the phenotype of mouse embryos lacking the V-ATPase c-subunit. The mutant embryos differentiated embryonic epithelial tissues, primitive endoderm, epiblast, and extraembryonic ectoderm; however, the organisation of these epithelia was severely affected. The apical-basal polarity in the visceral endoderm layer was not properly established in the mutant embryos, resulting in abnormal epithelial morphology. Thus, the function of V-ATPase is imperative for the establishment and/or maintenance of epithelial cell polarity, which is required for early embryogenesis.
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Affiliation(s)
- Ge-Hong Sun-Wada
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts, Kohdo, Kyotanabe, Kyoto, 610-0395, Japan
| | - Hiroyuki Tabata
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts, Kohdo, Kyotanabe, Kyoto, 610-0395, Japan.,Division of Biochemistry, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, 7-2-1 Kami-ohno, Himeji, Hyogo, 670-8524, Japan
| | - Yoh Wada
- Division of Biological Sciences, Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka, 567-0047, Japan.
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19
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Colombero C, Remy D, Antoine‐Bally S, Macé A, Monteiro P, ElKhatib N, Fournier M, Dahmani A, Montaudon E, Montagnac G, Marangoni E, Chavrier P. mTOR Repression in Response to Amino Acid Starvation Promotes ECM Degradation Through MT1-MMP Endocytosis Arrest. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2101614. [PMID: 34250755 PMCID: PMC8425857 DOI: 10.1002/advs.202101614] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 06/07/2021] [Indexed: 05/02/2023]
Abstract
Under conditions of starvation, normal and tumor epithelial cells can rewire their metabolism toward the consumption of extracellular proteins, including extracellular matrix-derived components as nutrient sources. The mechanism of pericellular matrix degradation by starved cells has been largely overlooked. Here it is shown that matrix degradation by breast and pancreatic tumor cells and patient-derived xenograft explants increases by one order of magnitude upon amino acid and growth factor deprivation. In addition, it is found that collagenolysis requires the invadopodia components, TKS5, and the transmembrane metalloproteinase, MT1-MMP, which are key to the tumor invasion program. Increased collagenolysis is controlled by mTOR repression upon nutrient depletion or pharmacological inhibition by rapamycin. The results reveal that starvation hampers clathrin-mediated endocytosis, resulting in MT1-MMP accumulation in arrested clathrin-coated pits. The study uncovers a new mechanism whereby mTOR repression in starved cells leads to the repurposing of abundant plasma membrane clathrin-coated pits into robust ECM-degradative assemblies.
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Affiliation(s)
| | - David Remy
- Institut CuriePSL Research UniversityCNRS UMR 144Paris75005France
| | | | - Anne‐Sophie Macé
- Institut CuriePSL Research UniversityCNRS UMR 144Paris75005France
- Cell and Tissue Imaging Facility (PICT‐IBiSA)Institut CuriePSL Research UniversityParis75005France
| | - Pedro Monteiro
- Institut CuriePSL Research UniversityCNRS UMR 144Paris75005France
| | - Nadia ElKhatib
- Gustave Roussy InstituteUniversité Paris‐SaclayINSERM U1279Villejuif94805France
| | - Margot Fournier
- Institut CuriePSL Research UniversityCNRS UMR 144Paris75005France
| | - Ahmed Dahmani
- Translational Research DepartmentInstitut CuriePSL Research UniversityParis75005France
| | - Elodie Montaudon
- Translational Research DepartmentInstitut CuriePSL Research UniversityParis75005France
| | - Guillaume Montagnac
- Gustave Roussy InstituteUniversité Paris‐SaclayINSERM U1279Villejuif94805France
| | - Elisabetta Marangoni
- Translational Research DepartmentInstitut CuriePSL Research UniversityParis75005France
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20
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Figueiredo M, Daryadel A, Sihn G, Müller DN, Popova E, Rouselle A, Nguyen G, Bader M, Wagner CA. The (pro)renin receptor (ATP6ap2) facilitates receptor-mediated endocytosis and lysosomal function in the renal proximal tubule. Pflugers Arch 2021; 473:1229-1246. [PMID: 34228176 PMCID: PMC8302575 DOI: 10.1007/s00424-021-02598-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 05/26/2021] [Accepted: 06/16/2021] [Indexed: 12/16/2022]
Abstract
The ATP6ap2 (Pro)renin receptor protein associates with H+-ATPases which regulate organellar, cellular, and systemic acid-base homeostasis. In the kidney, ATP6ap2 colocalizes with H+-ATPases in various cell types including the cells of the proximal tubule. There, H+-ATPases are involved in receptor-mediated endocytosis of low molecular weight proteins via the megalin/cubilin receptors. To study ATP6ap2 function in the proximal tubule, we used an inducible shRNA Atp6ap2 knockdown rat model (Kd) and an inducible kidney-specific Atp6ap2 knockout mouse model. Both animal lines showed higher proteinuria with elevated albumin, vitamin D binding protein, and procathepsin B in urine. Endocytosis of an injected fluid-phase marker (FITC- dextran, 10 kDa) was normal whereas processing of recombinant transferrin, a marker for receptor-mediated endocytosis, to lysosomes was delayed. While megalin and cubilin expression was unchanged, abundance of several subunits of the H+-ATPase involved in receptor-mediated endocytosis was reduced. Lysosomal integrity and H+-ATPase function are associated with mTOR signaling. In ATP6ap2, KO mice mTOR and phospho-mTOR appeared normal but increased abundance of the LC3-B subunit of the autophagosome was observed suggesting a more generalized impairment of lysosomal function in the absence of ATP6ap2. Hence, our data suggests a role for ATP6ap2 for proximal tubule function in the kidney with a defect in receptor-mediated endocytosis in mice and rats.
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Affiliation(s)
- Marta Figueiredo
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Arezoo Daryadel
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Gabin Sihn
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Dominik N Müller
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Str. 10, 13125, Berlin, Germany
- Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Elena Popova
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Anthony Rouselle
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | | | - Michael Bader
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Str. 10, 13125, Berlin, Germany.
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany.
- Charite University Medicine Berlin, Berlin, Germany.
- Institute for Biology, University of Lübeck, Lübeck, Germany.
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland.
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21
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Sun Y, Tan L, Neuman RI, Broekhuizen M, Schoenmakers S, Lu X, Danser AHJ. Megalin, Proton Pump Inhibitors and the Renin-Angiotensin System in Healthy and Pre-Eclamptic Placentas. Int J Mol Sci 2021; 22:ijms22147407. [PMID: 34299027 PMCID: PMC8306182 DOI: 10.3390/ijms22147407] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/06/2021] [Accepted: 07/08/2021] [Indexed: 12/22/2022] Open
Abstract
Soluble Fms-like tyrosine kinase-1 (sFlt-1) is increased in pre-eclampsia. The proton pump inhibitor (PPI) lowers sFlt-1, while angiotensin increases it. To investigate whether PPIs lower sFlt-1 by suppressing placental renin–angiotensin system (RAS) activity, we studied gene expression and protein abundance of RAS components, including megalin, a novel endocytic receptor for prorenin and renin, in placental tissue obtained from healthy pregnant women and women with early-onset pre-eclampsia. Renin, ACE, ACE2, and the angiotensin receptors were expressed at identical levels in healthy and pre-eclamptic placentas, while both the (pro)renin receptor and megalin were increased in the latter. Placental prorenin levels were upregulated in pre-eclamptic pregnancies. Angiotensinogen protein, but not mRNA, was detectable in placental tissue, implying that it originates from maternal blood. Ex vivo placental perfusion revealed a complete washout of angiotensinogen, while prorenin release remained constant. The PPI esomeprazole dose-dependently reduced megalin/(pro)renin receptor-mediated renin uptake in Brown Norway yolk sac epithelial cells and decreased sFlt-1 secretion from placental villous explants. Megalin inhibition blocked angiotensinogen uptake in epithelial cells. In conclusion, our data suggest that placental RAS activity depends on angiotensinogen taken up from the maternal systemic circulation. PPIs might interfere with placental (pro)renin-AGT uptake/transport, thereby reducing angiotensin formation as well as angiotensin-induced sFlt-1 synthesis.
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Affiliation(s)
- Yuan Sun
- Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC, 3015 CN Rotterdam, The Netherlands; (Y.S.); (L.T.); (R.I.N.); (M.B.)
- Department of Pharmacology, College of Pharmacy, Shenzhen Technology University, Shenzhen 518118, China
- Health Science Center, Department of Physiology, Shenzhen University, Shenzhen 518061, China;
| | - Lunbo Tan
- Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC, 3015 CN Rotterdam, The Netherlands; (Y.S.); (L.T.); (R.I.N.); (M.B.)
- Health Science Center, Department of Physiology, Shenzhen University, Shenzhen 518061, China;
| | - Rugina I. Neuman
- Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC, 3015 CN Rotterdam, The Netherlands; (Y.S.); (L.T.); (R.I.N.); (M.B.)
| | - Michelle Broekhuizen
- Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC, 3015 CN Rotterdam, The Netherlands; (Y.S.); (L.T.); (R.I.N.); (M.B.)
- Division of Neonatology, Department of Pediatrics, Erasmus MC, 3015 CN Rotterdam, The Netherlands
| | - Sam Schoenmakers
- Department of Obstetrics and Gynaecology, Erasmus MC, 3015 CN Rotterdam, The Netherlands;
| | - Xifeng Lu
- Health Science Center, Department of Physiology, Shenzhen University, Shenzhen 518061, China;
| | - A. H. Jan Danser
- Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC, 3015 CN Rotterdam, The Netherlands; (Y.S.); (L.T.); (R.I.N.); (M.B.)
- Correspondence: ; Tel.: +31-10-7043540
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22
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Heiden S, Siwek R, Lotz ML, Borkowsky S, Schröter R, Nedvetsky P, Rohlmann A, Missler M, Krahn MP. Apical-basal polarity regulators are essential for slit diaphragm assembly and endocytosis in Drosophila nephrocytes. Cell Mol Life Sci 2021; 78:3657-3672. [PMID: 33651172 PMCID: PMC8038974 DOI: 10.1007/s00018-021-03769-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 01/11/2021] [Accepted: 01/16/2021] [Indexed: 12/02/2022]
Abstract
Apical-basal polarity is a key feature of most epithelial cells and it is regulated by highly conserved protein complexes. In mammalian podocytes, which emerge from columnar epithelial cells, this polarity is preserved and the tight junctions are converted to the slit diaphragms, establishing the filtration barrier. In Drosophila, nephrocytes show several structural and functional similarities with mammalian podocytes and proximal tubular cells. However, in contrast to podocytes, little is known about the role of apical-basal polarity regulators in these cells. In this study, we used expansion microscopy and found the apical polarity determinants of the PAR/aPKC and Crb-complexes to be predominantly targeted to the cell cortex in proximity to the nephrocyte diaphragm, whereas basolateral regulators also accumulate intracellularly. Knockdown of PAR-complex proteins results in severe endocytosis and nephrocyte diaphragm defects, which is due to impaired aPKC recruitment to the plasma membrane. Similar, downregulation of most basolateral polarity regulators disrupts Nephrin localization but had surprisingly divergent effects on endocytosis. Our findings suggest that morphology and slit diaphragm assembly/maintenance of nephrocytes is regulated by classical apical-basal polarity regulators, which have distinct functions in endocytosis.
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Affiliation(s)
- Stefanie Heiden
- Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer Campus 1-A14, 48149, Münster, Germany
| | - Rebecca Siwek
- Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer Campus 1-A14, 48149, Münster, Germany
| | - Marie-Luise Lotz
- Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer Campus 1-A14, 48149, Münster, Germany
| | - Sarah Borkowsky
- Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer Campus 1-A14, 48149, Münster, Germany
| | - Rita Schröter
- Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer Campus 1-A14, 48149, Münster, Germany
| | - Pavel Nedvetsky
- Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer Campus 1-A14, 48149, Münster, Germany
| | - Astrid Rohlmann
- Institute of Anatomy and Molecular Neurobiology, University of Münster, Vesaliusweg 2-4, 48149, Münster, Germany
| | - Markus Missler
- Institute of Anatomy and Molecular Neurobiology, University of Münster, Vesaliusweg 2-4, 48149, Münster, Germany
| | - Michael P Krahn
- Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer Campus 1-A14, 48149, Münster, Germany.
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Hinden L, Kogot-Levin A, Tam J, Leibowitz G. Pathogenesis of diabesity-induced kidney disease: role of kidney nutrient sensing. FEBS J 2021; 289:901-921. [PMID: 33630415 DOI: 10.1111/febs.15790] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/09/2021] [Accepted: 02/24/2021] [Indexed: 12/11/2022]
Abstract
Diabetes kidney disease (DKD) is a major healthcare problem associated with increased risk for developing end-stage kidney disease and high mortality. It is widely accepted that DKD is primarily a glomerular disease. Recent findings however suggest that kidney proximal tubule cells (KPTCs) may play a central role in the pathophysiology of DKD. In diabetes and obesity, KPTCs are exposed to nutrient overload, including glucose, free-fatty acids and amino acids, which dysregulate nutrient and energy sensing by mechanistic target of rapamycin complex 1 and AMP-activated protein kinase, with subsequent induction of tubular injury, inflammation, and fibrosis. Pharmacological treatments that modulate nutrient sensing and signaling in KPTCs, including cannabinoid-1 receptor antagonists and sodium glucose transporter 2 inhibitors, exert robust kidney protective effects. Shedding light on how nutrients are sensed and metabolized in KPTCs and in other kidney domains, and on their effects on signal transduction pathways that mediate kidney injury, is important for understanding the pathophysiology of DKD and for the development of novel therapeutic approaches in DKD and probably also in other forms of kidney disease.
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Affiliation(s)
- Liad Hinden
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Israel
| | - Aviram Kogot-Levin
- Diabetes Unit and Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Joseph Tam
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Israel
| | - Gil Leibowitz
- Diabetes Unit and Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
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Nakamura M, Satoh N, Tsukada H, Mizuno T, Fujii W, Suzuki A, Horita S, Nangaku M, Suzuki M. Stimulatory effect of insulin on H+-ATPase in the proximal tubule via the Akt/mTORC2 pathway. Physiol Int 2020; 107:376-389. [PMID: 32990653 DOI: 10.1556/2060.2020.00030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Accepted: 06/12/2020] [Indexed: 11/19/2022]
Abstract
Purpose Acid-base transport in renal proximal tubules (PTs) is mainly sodium-dependent and conducted in coordination by the apical Na+/H+ exchanger (NHE3), vacuolar H+-adenosine triphosphatase (V-ATPase), and the basolateral Na+/HCO3- cotransporter. V-ATPase on PTs is well-known to play an important role in proton excretion. Recently we reported a stimulatory effect of insulin on these transporters. However, it is unclear whether insulin is involved in acid-base balance in PTs. Thus, we assessed the role of insulin in acid-base balance in PTs. Methods V-ATPase activity was evaluated using freshly isolated PTs obtained from mice, and specific inhibitors were then used to assess the signaling pathways involved in the observed effects. Results V-ATPase activity in PTs was markedly enhanced by insulin, and its activation was completely inhibited by bafilomycin (a V-ATPase-specific inhibitor), Akt inhibitor VIII, and PP242 (an mTORC1/2 inhibitor), but not by rapamycin (an mTORC1 inhibitor). V-ATPase activity was stimulated by 1 nm insulin by approximately 20% above baseline, which was completely suppressed by Akt1/2 inhibitor VIII. PP242 completely suppressed the insulin-mediated V-ATPase stimulation in mouse PTs, whereas rapamycin failed to influence the effect of insulin. Insulin-induced Akt phosphorylation in the mouse renal cortex was completely suppressed by Akt1/2 inhibitor VIII and PP242, but not by rapamycin. Conclusion Our results indicate that stimulation of V-ATPase activity by insulin in PTs is mediated via the Akt2/mTORC2 pathway. These results reveal the mechanism underlying the complex signaling in PT acid-base balance, providing treatment targets for renal disease.
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Affiliation(s)
- M Nakamura
- 1Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - N Satoh
- 1Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - H Tsukada
- 1Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - T Mizuno
- 1Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - W Fujii
- 1Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - A Suzuki
- 1Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan.,2Department of Nephrology, Japan Community Health care Organization (JCHO), Tokyo Yamate Medical Center, Tokyo, Japan
| | - S Horita
- 1Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - M Nangaku
- 1Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - M Suzuki
- 3Health Service Center, Tokyo Gakugei University, Tokyo, Japan
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Mo D, Chen Y, Jiang N, Shen J, Zhang J. Investigation of Isoform Specific Functions of the V-ATPase a Subunit During Drosophila Wing Development. Front Genet 2020; 11:723. [PMID: 32754202 PMCID: PMC7365883 DOI: 10.3389/fgene.2020.00723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 06/15/2020] [Indexed: 12/12/2022] Open
Abstract
The vacuolar ATPases (V-ATPases) are ATP-dependent proton pumps that play vital roles in eukaryotic cells. Insect V-ATPases are required in nearly all epithelial tissues to regulate a multiplicity of processes including receptor-mediated endocytosis, protein degradation, fluid secretion, and neurotransmission. Composed of fourteen different subunits, several V-ATPase subunits exist in distinct isoforms to perform cell type specific functions. The 100 kD a subunit (Vha100) of V-ATPases are encoded by a family of five genes in Drosophila, but their assignments are not fully understood. Here we report an experimental survey of the Vha100 gene family during Drosophila wing development. A combination of CRISPR-Cas9 mutagenesis, somatic clonal analysis and in vivo RNAi assays is used to characterize the requirement of Vha100 isoforms, and mutants of Vha100-2, Vha100-3, Vha100-4, and Vha100-5 genes were generated. We show that Vha100-3 and Vha100-5 are dispensable for fly development, while Vha100-1 is not critically required in the wing. As for the other two isoforms, we find that Vha100-2 regulates wing cuticle maturation, while Vha100-4 is the single isoform involved in developmental patterning. More specifically, Vha100-4 is required for proper activation of the Wingless signaling pathway during fly wing development. Interestingly, we also find a specific genetic interaction between Vha100-1 and Vha100-4 during wing development. Our results revealed the distinct roles of Vha100 isoforms during insect wing development, providing a rationale for understanding the diverse roles of V-ATPases.
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Affiliation(s)
- Dongqing Mo
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Yao Chen
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Na Jiang
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Jie Shen
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Junzheng Zhang
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
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Zellmer J, Yen HY, Kaiser L, Mille E, Gildehaus FJ, Böning G, Steiger K, Hacker M, Bartenstein P, Todica A, Haug AR, Ilhan H. Toxicity of a combined therapy using the mTOR-inhibitor everolimus and PRRT with [ 177Lu]Lu-DOTA-TATE in Lewis rats. EJNMMI Res 2020; 10:41. [PMID: 32335736 PMCID: PMC7183514 DOI: 10.1186/s13550-020-00628-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 04/07/2020] [Indexed: 02/08/2023] Open
Abstract
PURPOSE Peptide receptor radionuclide therapy (PRRT) with [177Lu]Lu-DOTA0,TYR3-octreotate ([177Lu]Lu-DOTA-TATE) and the mechanistic target of rapamycin (mTOR) inhibitor everolimus are both approved for the treatment of neuroendocrine tumours (NET). However, tumour progression is still frequent, and treatment strategies need further improvement. One possible approach could be to combine different therapy options. In this study, we investigated the toxicity of a combined treatment with everolimus and [177Lu]Lu-DOTA-TATE in female Lewis rats. METHODS Animals received 200 MBq of [177Lu]Lu-DOTA-TATE once and/or 5 mg/kg body weight everolimus or placebo weekly for 16 weeks and were divided into four groups (group 1, placebo; group 2, everolimus; group 3, placebo + [177Lu]Lu-DOTA-TATE; group 4, everolimus + [177Lu]Lu-DOTA-TATE). Blood levels of creatinine and blood urea nitrogen (BUN) were assessed weekly to monitor nephrotoxicity, and a full blood count was performed at the time of euthanasia to monitor myelotoxicity. Additionally, renal function was analysed by sequential [99mTc]Tc-mercaptoacetyltriglycine ([99mTc]Tc-MAG3) scintigraphies. Histopathological examination was performed in all the kidneys using a standardized renal damage score (RDS). RESULTS Rats receiving everolimus showed a significantly lower increase in creatinine levels than those receiving placebo. Everolimus therapy reduced white blood count significantly, which was not observed for [177Lu]Lu-DOTA-TATE. Functional renal scintigraphies using [99mTc]Tc-MAG3 showed a compromised initial tracer uptake after PRRT and slower but still preserved excretion after everolimus. Histology showed no significant RDS differences between groups. CONCLUSION Renal scintigraphy is a highly sensitive tool for the detection of renal function impairment after a combination of everolimus and PRRT. Additional treatment with everolimus does not increase renal and haematological toxicity of PRRT with [177Lu]Lu-DOTA-TATE.
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Affiliation(s)
- Johannes Zellmer
- Department of Nuclear Medicine, University Hospital, Ludwig-Maxilimians-University Munich, Munich, Germany
| | - Hsi-Yu Yen
- Department of Pathology, Technical University of Munich, Munich, Germany
- German Cancer Consortium (DKTK), German Cancer Research Centre (DKFZ), Heidelberg, Germany
- Comparative Experimental Pathology, Technical University of Munich, Munich, Germany
| | - Lena Kaiser
- Department of Nuclear Medicine, University Hospital, Ludwig-Maxilimians-University Munich, Munich, Germany
| | - Erik Mille
- Department of Nuclear Medicine, University Hospital, Ludwig-Maxilimians-University Munich, Munich, Germany
| | - Franz Josef Gildehaus
- Department of Nuclear Medicine, University Hospital, Ludwig-Maxilimians-University Munich, Munich, Germany
| | - Guido Böning
- Department of Nuclear Medicine, University Hospital, Ludwig-Maxilimians-University Munich, Munich, Germany
| | - Katja Steiger
- Department of Pathology, Technical University of Munich, Munich, Germany
- Comparative Experimental Pathology, Technical University of Munich, Munich, Germany
| | - Marcus Hacker
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria
| | - Peter Bartenstein
- Department of Nuclear Medicine, University Hospital, Ludwig-Maxilimians-University Munich, Munich, Germany
| | - Andrei Todica
- Department of Nuclear Medicine, University Hospital, Ludwig-Maxilimians-University Munich, Munich, Germany
| | - Alexander R Haug
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria
| | - Harun Ilhan
- Department of Nuclear Medicine, University Hospital, Ludwig-Maxilimians-University Munich, Munich, Germany.
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Sun Y, Goes Martini A, Janssen MJ, Garrelds IM, Masereeuw R, Lu X, Danser AHJ. Megalin: A Novel Endocytic Receptor for Prorenin and Renin. Hypertension 2020; 75:1242-1250. [PMID: 32200675 DOI: 10.1161/hypertensionaha.120.14845] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Megalin is an endocytic receptor contributing to protein reabsorption. Impaired expression or trafficking of megalin increases urinary renin and allowed the detection of prorenin, which normally is absent in urine. Here, we investigated (pro)renin uptake by megalin, using both conditionally immortalized proximal tubule epithelial cells and Brown Norway Rat yolk sac cells (BN16). To distinguish binding and internalization, cells were incubated with recombinant human (pro)renin at 4°C and 37°C, respectively. (Pro)renin levels were assessed by immunoradiometric assay. At 4°C, BN16 cells bound 3× more prorenin than renin, suggestive for a higher affinity of prorenin. Similarly, at 37°C, prorenin accumulated at 3- to 4-fold higher levels than renin in BN16 cells. Consequently, depletion of medium prorenin (but not renin) content occurred after 24 hours. No such differences were observed in conditionally immortalized proximal tubule epithelial cells, and M6P (mannose-6-phosphate) greatly reduced conditionally immortalized proximal tubule epithelial cells (pro)renin uptake, suggesting that these cells accumulate (pro)renin largely via M6P receptors. M6P did not affect (pro)renin uptake in BN16 cells. Yet, inhibiting megalin expression with siRNA greatly reduced (pro)renin binding and internalization by BN16 cells. Furthermore, treating BN16 cells with albumin, an endogenous ligand of megalin, also decreased binding and internalization of (pro)renin, while deleting the (pro)renin receptor affected the latter only. Exposing prorenin's prosegment with the renin inhibitor aliskiren dramatically increased prorenin binding, while after prosegment cleavage with trypsin prorenin binding was identical to that of renin. In conclusion, megalin might function as an endocytic receptor for (pro)renin and displays a preference for prorenin. Megalin-mediated endocytosis requires the (pro)renin receptor.
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Affiliation(s)
- Yuan Sun
- From the Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands (Y.S., A.G.M., I.M.G., A.H.J.D.).,Department of Physiology, Shenzhen University Health Science Center, Shenzhen University, China (Y.S., X.L.).,Translational Medicine Collaborative Innovation Center, The Second Clinical Medical College (Shenzhen People's Hospital) of Jinan University, Shenzhen, China (Y.S.)
| | - Alexandre Goes Martini
- From the Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands (Y.S., A.G.M., I.M.G., A.H.J.D.)
| | - Manoe J Janssen
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, the Netherlands (M.J.J., R.M.)
| | - Ingrid M Garrelds
- From the Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands (Y.S., A.G.M., I.M.G., A.H.J.D.)
| | - Rosalinde Masereeuw
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, the Netherlands (M.J.J., R.M.)
| | - Xifeng Lu
- Department of Physiology, Shenzhen University Health Science Center, Shenzhen University, China (Y.S., X.L.)
| | - A H Jan Danser
- From the Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands (Y.S., A.G.M., I.M.G., A.H.J.D.)
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Abstract
PURPOSE OF REVIEW Megalin is well known for its role in the reabsorption of proteins from the ultrafiltrate. Recent studies suggest that megalin also reabsorbs renin and angiotensinogen. Indeed, without megalin urinary renin and angiotensinogen levels massively increase, and even prorenin becomes detectable in urine. RECENT FINDINGS Intriguingly, megalin might also contribute to renal angiotensin production, as evidenced from studies in megalin knockout mice. This review discusses these topics critically, concluding that urinary renin-angiotensin system components reflect diminished reabsorption rather than release from renal tissue sites and that alterations in renal renin levels or megalin-dependent signaling need to be ruled out before concluding that angiotensin production at renal tissue sites is truly megalin dependent. Future studies should evaluate megalin-mediated renin/angiotensinogen transcytosis (allowing interstitial angiotensin generation), and determine whether megalin prefers prorenin over renin, thus explaining why urine normally contains no prorenin.
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Affiliation(s)
- Yuan Sun
- Department of Internal Medicine, Division of Pharmacology and Vascular Medicine, Erasmus MC, room EE1418b, Wytemaweg 80, 3015 CN, Rotterdam, The Netherlands
- Department of Physiology, Shenzhen University Health Science Center, Shenzhen University, Shenzhen, China
- Translational Medicine Collaborative Innovation Center, The Second Clinical Medical College (Shenzhen People's Hospital) of Jinan University, Shenzhen, China
| | - Xifeng Lu
- Department of Physiology, Shenzhen University Health Science Center, Shenzhen University, Shenzhen, China
| | - A H Jan Danser
- Department of Internal Medicine, Division of Pharmacology and Vascular Medicine, Erasmus MC, room EE1418b, Wytemaweg 80, 3015 CN, Rotterdam, The Netherlands.
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Coordination of host and symbiont gene expression reveals a metabolic tug-of-war between aphids and Buchnera. Proc Natl Acad Sci U S A 2020; 117:2113-2121. [PMID: 31964845 DOI: 10.1073/pnas.1916748117] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Symbioses between animals and microbes are often described as mutualistic, but are subject to tradeoffs that may manifest as shifts in host and symbiont metabolism, cellular processes, or symbiont density. In pea aphids, the bacterial symbiont Buchnera is confined to specialized aphid cells called bacteriocytes, where it produces essential amino acids needed by hosts. This relationship is dynamic; Buchnera titer varies within individual aphids and among different clonal aphid lineages, and is affected by environmental and host genetic factors. We examined how host genotypic variation relates to host and symbiont function among seven aphid clones differing in Buchnera titer. We found that bacteriocyte gene expression varies among individual aphids and among aphid clones, and that Buchnera gene expression changes in response. By comparing hosts with low and high Buchnera titer, we found that aphids and Buchnera oppositely regulate genes underlying amino acid biosynthesis and cell growth. In high-titer hosts, both bacteriocytes and symbionts show elevated expression of genes underlying energy metabolism. Several eukaryotic cell signaling pathways are differentially expressed in bacteriocytes of low- versus high-titer hosts: Cell-growth pathways are up-regulated in low-titer genotypes, while membrane trafficking, lysosomal processes, and mechanistic target of rapamycin (mTOR) and cytokine pathways are up-regulated in high-titer genotypes. Specific Buchnera functions are up-regulated within different bacteriocyte environments, with genes underlying flagellar body secretion and flagellar assembly overexpressed in low- and high-titer hosts, respectively. Overall, our results reveal allowances and demands made by both host and symbiont engaged in a metabolic "tug-of-war."
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Rahmani S, Defferrari MS, Wakarchuk WW, Antonescu CN. Energetic adaptations: Metabolic control of endocytic membrane traffic. Traffic 2019; 20:912-931. [DOI: 10.1111/tra.12705] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 09/11/2019] [Accepted: 10/13/2019] [Indexed: 12/18/2022]
Affiliation(s)
- Sadia Rahmani
- Department of Chemistry and BiologyRyerson University Toronto Ontario Canada
| | | | - Warren W. Wakarchuk
- Department of Chemistry and BiologyRyerson University Toronto Ontario Canada
- Department of Biological SciencesUniversity of Alberta Edmonton Alberta Canada
| | - Costin N. Antonescu
- Department of Chemistry and BiologyRyerson University Toronto Ontario Canada
- Keenan Research Centre for Biomedical Science of St. Michael's Hospital Toronto Ontario Canada
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31
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Marelja Z, Simons M. Filling the Gap: Drosophila Nephrocytes as Model System in Kidney Research. J Am Soc Nephrol 2019; 30:719-720. [PMID: 30910933 DOI: 10.1681/asn.2019020181] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Affiliation(s)
- Zvonimir Marelja
- INSERM UMR1163, Laboratory of Epithelial Biology and Disease, Imagine Institute, Paris Descartes University, Sorbonne Paris Cité, Hôpital Necker-Enfants Malades, Paris, France
| | - Matias Simons
- INSERM UMR1163, Laboratory of Epithelial Biology and Disease, Imagine Institute, Paris Descartes University, Sorbonne Paris Cité, Hôpital Necker-Enfants Malades, Paris, France
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Kozyraki R, Cases O. Cubilin, the Intrinsic Factor-Vitamin B12 Receptor in Development and Disease. Curr Med Chem 2018; 27:3123-3150. [PMID: 30295181 DOI: 10.2174/0929867325666181008143945] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 08/11/2018] [Accepted: 08/21/2018] [Indexed: 12/29/2022]
Abstract
Gp280/Intrinsic factor-vitamin B12 receptor/Cubilin (CUBN) is a large endocytic receptor serving multiple functions in vitamin B12 homeostasis, renal reabsorption of protein or toxic substances including albumin, vitamin D-binding protein or cadmium. Cubilin is a peripheral membrane protein consisting of 8 Epidermal Growth Factor (EGF)-like repeats and 27 CUB (defined as Complement C1r/C1s, Uegf, BMP1) domains. This structurally unique protein interacts with at least two molecular partners, Amnionless (AMN) and Lrp2/Megalin. AMN is involved in appropriate plasma membrane transport of Cubilin whereas Lrp2 is essential for efficient internalization of Cubilin and its ligands. Observations gleaned from animal models with Cubn deficiency or human diseases demonstrate the importance of this protein. In this review addressed to basic research and medical scientists, we summarize currently available data on Cubilin and its implication in renal and intestinal biology. We also discuss the role of Cubilin as a modulator of Fgf8 signaling during embryonic development and propose that the Cubilin-Fgf8 interaction may be relevant in human pathology, including in cancer progression, heart or neural tube defects. We finally provide experimental elements suggesting that some aspects of Cubilin physiology might be relevant in drug design.
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Affiliation(s)
- Renata Kozyraki
- INSERM UMRS 1138, Centre de Recherche des Cordeliers, Paris-Diderot University, Paris, France
| | - Olivier Cases
- INSERM UMRS 1138, Centre de Recherche des Cordeliers, Paris-Diderot University, Paris, France
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Tamirisa S, Papagiannouli F, Rempel E, Ermakova O, Trost N, Zhou J, Mundorf J, Brunel S, Ruhland N, Boutros M, Lohmann JU, Lohmann I. Decoding the Regulatory Logic of the Drosophila Male Stem Cell System. Cell Rep 2018; 24:3072-3086. [DOI: 10.1016/j.celrep.2018.08.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 04/13/2018] [Accepted: 08/06/2018] [Indexed: 10/28/2022] Open
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Wissel S, Harzer H, Bonnay F, Burkard TR, Neumüller RA, Knoblich JA. Time-resolved transcriptomics in neural stem cells identifies a v-ATPase/Notch regulatory loop. J Cell Biol 2018; 217:3285-3300. [PMID: 29959232 PMCID: PMC6123005 DOI: 10.1083/jcb.201711167] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 04/25/2018] [Accepted: 06/11/2018] [Indexed: 12/14/2022] Open
Abstract
Drosophila melanogaster neural stem cells (neuroblasts) divide asymmetrically by differentially segregating protein determinants into their daughter cells. Wissel et al. use time-resolved transcriptional profiling to identify a v-ATPase/Notch regulatory loop that acts in multiple stem cell lineages both during nervous system development and in the adult gut. Drosophila melanogaster neural stem cells (neuroblasts [NBs]) divide asymmetrically by differentially segregating protein determinants into their daughter cells. Although the machinery for asymmetric protein segregation is well understood, the events that reprogram one of the two daughter cells toward terminal differentiation are less clear. In this study, we use time-resolved transcriptional profiling to identify the earliest transcriptional differences between the daughter cells on their way toward distinct fates. By screening for coregulated protein complexes, we identify vacuolar-type H+–ATPase (v-ATPase) among the first and most significantly down-regulated complexes in differentiating daughter cells. We show that v-ATPase is essential for NB growth and persistent activity of the Notch signaling pathway. Our data suggest that v-ATPase and Notch form a regulatory loop that acts in multiple stem cell lineages both during nervous system development and in the adult gut. We provide a unique resource for investigating neural stem cell biology and demonstrate that cell fate changes can be induced by transcriptional regulation of basic, cell-essential pathways.
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Affiliation(s)
- Sebastian Wissel
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
| | - Heike Harzer
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
| | - François Bonnay
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
| | - Thomas R Burkard
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
| | - Ralph A Neumüller
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
| | - Juergen A Knoblich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
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35
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Bryniarski MA, Yee BM, Jaffri I, Chaves LD, Yu JA, Guan X, Ghavam N, Yacoub R, Morris ME. Increased megalin expression in early type 2 diabetes: role of insulin-signaling pathways. Am J Physiol Renal Physiol 2018; 315:F1191-F1207. [PMID: 29949391 DOI: 10.1152/ajprenal.00210.2018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The megalin/cubilin complex is responsible for the majority of serum protein reclamation in the proximal tubules. The current study examined if decreases in their renal expression, along with the albumin recycling protein neonatal Fc receptor (FcRn) could account for proteinuria/albuminuria in the Zucker diabetic fatty rat model of type 2 diabetes. Immunoblots of renal cortex samples obtained at worsening disease stages demonstrated no loss in megalin, cubilin, or FcRn, even when proteinuria was measured. Additionally, early diabetic rats exhibited significantly increased renal megalin expression when compared with controls (adjusted P < 0.01). Based on these results, the ability of insulin to increase megalin was examined in a clonal subpopulation of the opossum kidney proximal tubule cell line. Insulin treatments (24 h, 100 nM) under high glucose conditions significantly increased megalin protein ( P < 0.0001), mRNA ( P < 0.0001), and albumin endocytosis. The effect on megalin expression was prevented with inhibitors against key effectors of insulin intracellular signaling, phosphatidylinositide 3-kinase and Akt. Studies using rapamycin to inhibit the mechanistic target of rapamycin complex 1 (mTORC1) resulted in a loss of insulin-induced megalin expression. However, subsequent evaluation demonstrated these effects were independent of initial mTORC1 suppression. The presented results provide insight into the expression of megalin, cubilin, and FcRn in type 2 diabetes, which may be impacted by elevated insulin and glucose. Furthermore, proximal tubule endocytic activity in early diabetics may be enhanced, a process that could have a significant role in proteinuria-induced renal damage.
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Affiliation(s)
- Mark A Bryniarski
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo , New York
| | - Benjamin M Yee
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo , New York
| | - Irum Jaffri
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo , New York
| | - Lee D Chaves
- Department of Internal Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo , New York
| | - Jin Ah Yu
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo , New York
| | - Xiaowen Guan
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo , New York
| | - Nazanin Ghavam
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo , New York
| | - Rabi Yacoub
- Department of Internal Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo , New York
| | - Marilyn E Morris
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo , New York
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36
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Affiliation(s)
- Matias Simons
- Laboratory of Epithelial Biology and Disease, Imagine Institute, Paris, France; and Imagine Institute, Université Paris-Descartes-Sorbonne Paris Cité, Paris, France
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37
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Zhu M, Zhang S, Tian X, Wu C. Mask mitigates MAPT- and FUS-induced degeneration by enhancing autophagy through lysosomal acidification. Autophagy 2017; 13:1924-1938. [PMID: 28806139 PMCID: PMC5788473 DOI: 10.1080/15548627.2017.1362524] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Accumulation of intracellular misfolded or damaged proteins is associated with both normal aging and late-onset degenerative diseases. Two cellular clearance mechanisms, the ubiquitin-proteasome system (UPS) and the macroautophagy/autophagy-lysosomal pathway, work in concert to degrade harmful protein aggregates and maintain protein homeostasis. Here we show that Mask, an Ankyrin-repeat and KH-domain containing protein, plays a key role in promoting autophagy flux and mitigating degeneration caused by protein aggregation or impaired UPS function. In Drosophila eye models of human tauopathy or amyotrophic lateral sclerosis diseases, loss of Mask function enhanced, while gain of Mask function mitigated, eye degenerations induced by eye-specific expression of human pathogenic MAPT/TAU or FUS proteins. The fly larval muscle, a more accessible tissue, was then used to study the underlying molecular mechanisms in vivo. We found that Mask modulates the global abundance of K48- and K63-ubiquitinated proteins by regulating autophagy-lysosome-mediated degradation, but not UPS function. Indeed, upregulation of Mask compensated the partial loss of UPS function. We further demonstrate that Mask promotes autophagic flux by enhancing lysosomal function, and that Mask is necessary and sufficient for promoting the expression levels of the proton-pumping vacuolar (V)-type ATPases in a TFEB-independent manner. Moreover, the beneficial effects conferred by Mask expression on the UPS dysfunction and neurodegenerative models depend on intact autophagy-lysosomal pathway. Our findings highlight the importance of lysosome acidification in cellular surveillance mechanisms and establish a model for exploring strategies to mitigate neurodegeneration by boosting lysosomal function.
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Affiliation(s)
- Mingwei Zhu
- a Neuroscience Center of Excellence, Department of Cell Biology and Anatomy , Louisiana State University Health Sciences Center , New Orleans , LA , USA
| | - Sheng Zhang
- b The Brown Foundation Institute of Molecular Medicine and Department of Neurobiology and Anatomy , McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth) , Houston , TX , USA
| | - Xiaolin Tian
- a Neuroscience Center of Excellence, Department of Cell Biology and Anatomy , Louisiana State University Health Sciences Center , New Orleans , LA , USA
| | - Chunlai Wu
- a Neuroscience Center of Excellence, Department of Cell Biology and Anatomy , Louisiana State University Health Sciences Center , New Orleans , LA , USA
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38
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Abstract
The vacuolar ATPases (V-ATPases) are a family of proton pumps that couple ATP hydrolysis to proton transport into intracellular compartments and across the plasma membrane. They function in a wide array of normal cellular processes, including membrane traffic, protein processing and degradation, and the coupled transport of small molecules, as well as such physiological processes as urinary acidification and bone resorption. The V-ATPases have also been implicated in a number of disease processes, including viral infection, renal disease, and bone resorption defects. This review is focused on the growing evidence for the important role of V-ATPases in cancer. This includes functions in cellular signaling (particularly Wnt, Notch, and mTOR signaling), cancer cell survival in the highly acidic environment of tumors, aiding the development of drug resistance, as well as crucial roles in tumor cell invasion, migration, and metastasis. Of greatest excitement is evidence that at least some tumors express isoforms of V-ATPase subunits whose disruption is not lethal, leading to the possibility of developing anti-cancer therapeutics that selectively target V-ATPases that function in cancer cells.
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Affiliation(s)
- Laura Stransky
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, and Program in Cellular and Molecular Physiology, Program in Biochemistry, and Program in Cell, Molecular and Developmental Biology, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, Massachusetts
| | - Kristina Cotter
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, and Program in Cellular and Molecular Physiology, Program in Biochemistry, and Program in Cell, Molecular and Developmental Biology, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, Massachusetts
| | - Michael Forgac
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, and Program in Cellular and Molecular Physiology, Program in Biochemistry, and Program in Cell, Molecular and Developmental Biology, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, Massachusetts
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39
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Helmstädter M, Simons M. Using Drosophila nephrocytes in genetic kidney disease. Cell Tissue Res 2017; 369:119-126. [PMID: 28401308 DOI: 10.1007/s00441-017-2606-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 03/05/2017] [Indexed: 01/01/2023]
Abstract
Renal diseases are a growing health burden, and innovative models to study their pathomechanisms are greatly needed. Here, we highlight how the fruit fly Drosophila melanogaster can be used to model kidney diseases. We focus on the nephrocyte that has recently been shown to exhibit podocyte and proximal tubular cell features. These cells can be manipulated with precise genetic tools to dissect filtration and reabsorption mechanisms. Thus, they represent a novel and easy-to-use alternative in experimental nephrology.
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Affiliation(s)
- Martin Helmstädter
- Renal Division, University Hospital Freiburg, Hugstetter Strasse 55, 79106, Freiburg, Germany
| | - Matias Simons
- Imagine Institute, Paris Descartes University-Sorbonne Paris Cité, 75015, Paris, France. .,Institut Imagine, 24 Boulevard du Montparnasse, Paris, France.
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40
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Mitchell CL, Latuszek CE, Vogel KR, Greenlund IM, Hobmeier RE, Ingram OK, Dufek SR, Pecore JL, Nip FR, Johnson ZJ, Ji X, Wei H, Gailing O, Werner T. α-amanitin resistance in Drosophila melanogaster: A genome-wide association approach. PLoS One 2017; 12:e0173162. [PMID: 28241077 PMCID: PMC5328632 DOI: 10.1371/journal.pone.0173162] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 02/15/2017] [Indexed: 11/17/2022] Open
Abstract
We investigated the mechanisms of mushroom toxin resistance in the Drosophila Genetic Reference Panel (DGRP) fly lines, using genome-wide association studies (GWAS). While Drosophila melanogaster avoids mushrooms in nature, some lines are surprisingly resistant to α-amanitin—a toxin found solely in mushrooms. This resistance may represent a pre-adaptation, which might enable this species to invade the mushroom niche in the future. Although our previous microarray study had strongly suggested that pesticide-metabolizing detoxification genes confer α-amanitin resistance in a Taiwanese D. melanogaster line Ama-KTT, none of the traditional detoxification genes were among the top candidate genes resulting from the GWAS in the current study. Instead, we identified Megalin, Tequila, and widerborst as candidate genes underlying the α-amanitin resistance phenotype in the North American DGRP lines, all three of which are connected to the Target of Rapamycin (TOR) pathway. Both widerborst and Tequila are upstream regulators of TOR, and TOR is a key regulator of autophagy and Megalin-mediated endocytosis. We suggest that endocytosis and autophagy of α-amanitin, followed by lysosomal degradation of the toxin, is one of the mechanisms that confer α-amanitin resistance in the DGRP lines.
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Affiliation(s)
- Chelsea L Mitchell
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Catrina E Latuszek
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Kara R Vogel
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, 1300 University Ave., Madison, WI, United States of America
| | - Ian M Greenlund
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Rebecca E Hobmeier
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Olivia K Ingram
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Shannon R Dufek
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Jared L Pecore
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Felicia R Nip
- College of Human Medicine, Michigan State University, Clinical Center, East Lansing, MI, United States of America
| | - Zachary J Johnson
- U.S. Forest Service, Salt Lake Ranger District 6944 S, 3000 E, Salt Lake City, UT, United States of America
| | - Xiaohui Ji
- School of Forest Resources and Environmental Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Hairong Wei
- School of Forest Resources and Environmental Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Oliver Gailing
- School of Forest Resources and Environmental Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Thomas Werner
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
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41
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Helmstädter M, Huber TB, Hermle T. Using the Drosophila Nephrocyte to Model Podocyte Function and Disease. Front Pediatr 2017; 5:262. [PMID: 29270398 PMCID: PMC5725439 DOI: 10.3389/fped.2017.00262] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 11/24/2017] [Indexed: 12/19/2022] Open
Abstract
Glomerular disorders are a major cause of end-stage renal disease and effective therapies are often lacking. Nephrocytes are considered to be part of the Drosophila excretory system and form slit diaphragms across cellular membrane invaginations. Nehphrocytes have been shown to share functional, morphological, and molecular features with podocytes, which form the glomerular filter in vertebrates. Here, we report the progress and the evolving tool-set of this model system. Combining a functional, accessible slit diaphragm with the power of the genetic tool-kit in Drosophila, the nephrocyte has the potential to greatly advance our understanding of the glomerular filtration barrier in health and disease.
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Affiliation(s)
- Martin Helmstädter
- Renal Division, University Medical Center Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Tobias B Huber
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tobias Hermle
- Renal Division, University Medical Center Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
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42
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Cherqui S, Courtoy PJ. The renal Fanconi syndrome in cystinosis: pathogenic insights and therapeutic perspectives. Nat Rev Nephrol 2016; 13:115-131. [PMID: 27990015 DOI: 10.1038/nrneph.2016.182] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Cystinosis is an autosomal recessive metabolic disease that belongs to the family of lysosomal storage disorders. It is caused by a defect in the lysosomal cystine transporter, cystinosin, which results in an accumulation of cystine in all organs. Despite the ubiquitous expression of cystinosin, a renal Fanconi syndrome is often the first manifestation of cystinosis, usually presenting within the first year of life and characterized by the early and severe dysfunction of proximal tubule cells, highlighting the unique vulnerability of this cell type. The current therapy for cystinosis, cysteamine, facilitates lysosomal cystine clearance and greatly delays progression to kidney failure but is unable to correct the Fanconi syndrome. This Review summarizes decades of studies that have fostered a better understanding of the pathogenesis of the renal Fanconi syndrome associated with cystinosis. These studies have unraveled some of the early molecular changes that occur before the onset of tubular atrophy and identified a role for cystinosin beyond cystine transport, in endolysosomal trafficking and proteolysis, lysosomal clearance, autophagy and the regulation of energy balance. These studies have also led to the identification of new potential therapeutic targets and here, we outline the potential role of stem cell therapy for cystinosis and provide insights into the mechanism of haematopoietic stem cell-mediated kidney protection.
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Affiliation(s)
- Stephanie Cherqui
- Department of Pediatrics, Division of Genetics, University of California San Diego, 9500 Gilman Drive, MC 0734, La Jolla, California 92093-0734, USA
| | - Pierre J Courtoy
- Cell biology, de Duve Institute and Université catholique de Louvain, UCL-Brussels, 75 Avenue Hippocrate, B-1200 Brussels, Belgium
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43
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Hermle T, Braun DA, Helmstädter M, Huber TB, Hildebrandt F. Modeling Monogenic Human Nephrotic Syndrome in the Drosophila Garland Cell Nephrocyte. J Am Soc Nephrol 2016; 28:1521-1533. [PMID: 27932481 DOI: 10.1681/asn.2016050517] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 11/05/2016] [Indexed: 11/03/2022] Open
Abstract
Steroid-resistant nephrotic syndrome is characterized by podocyte dysfunction. Drosophila garland cell nephrocytes are podocyte-like cells and thus provide a potential in vivo model in which to study the pathogenesis of nephrotic syndrome. However, relevant pathomechanisms of nephrotic syndrome have not been studied in nephrocytes. Here, we discovered that two Drosophila slit diaphragm proteins, orthologs of the human genes encoding nephrin and nephrin-like protein 1, colocalize within a fingerprint-like staining pattern that correlates with ultrastructural morphology. Using RNAi and conditional CRISPR/Cas9 in nephrocytes, we found this pattern depends on the expression of both orthologs. Tracer endocytosis by nephrocytes required Cubilin and reflected size selectivity analogous to that of glomerular function. Using RNAi and tracer endocytosis as a functional read-out, we screened Drosophila orthologs of human monogenic causes of nephrotic syndrome and observed conservation of the central pathogenetic alterations. We focused on the coenzyme Q10 (CoQ10) biosynthesis gene Coq2, the silencing of which disrupted slit diaphragm morphology. Restoration of CoQ10 synthesis by vanillic acid partially rescued the phenotypic and functional alterations induced by Coq2-RNAi. Notably, Coq2 colocalized with mitochondria, and Coq2 silencing increased the formation of reactive oxygen species (ROS). Silencing of ND75, a subunit of the mitochondrial respiratory chain that controls ROS formation independently of CoQ10, phenocopied the effect of Coq2-RNAi. Moreover, the ROS scavenger glutathione partially rescued the effects of Coq2-RNAi. In conclusion, Drosophila garland cell nephrocytes provide a model with which to study the pathogenesis of nephrotic syndrome, and ROS formation may be a pathomechanism of COQ2-nephropathy.
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Affiliation(s)
- Tobias Hermle
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts;
| | - Daniela A Braun
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Martin Helmstädter
- Renal Division, University Medical Center Freiburg, Freiburg, Germany, Faculty of Medicine, University of Freiburg, Freiburg, Germany; and
| | - Tobias B Huber
- Renal Division, University Medical Center Freiburg, Freiburg, Germany, Faculty of Medicine, University of Freiburg, Freiburg, Germany; and.,BIOSS Center for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Friedhelm Hildebrandt
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts;
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44
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Roles of mTOR complexes in the kidney: implications for renal disease and transplantation. Nat Rev Nephrol 2016; 12:587-609. [PMID: 27477490 DOI: 10.1038/nrneph.2016.108] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The mTOR pathway has a central role in the regulation of cell metabolism, growth and proliferation. Studies involving selective gene targeting of mTOR complexes (mTORC1 and mTORC2) in renal cell populations and/or pharmacologic mTOR inhibition have revealed important roles of mTOR in podocyte homeostasis and tubular transport. Important advances have also been made in understanding the role of mTOR in renal injury, polycystic kidney disease and glomerular diseases, including diabetic nephropathy. Novel insights into the roles of mTORC1 and mTORC2 in the regulation of immune cell homeostasis and function are helping to improve understanding of the complex effects of mTOR targeting on immune responses, including those that impact both de novo renal disease and renal allograft outcomes. Extensive experience in clinical renal transplantation has resulted in successful conversion of patients from calcineurin inhibitors to mTOR inhibitors at various times post-transplantation, with excellent long-term graft function. Widespread use of this practice has, however, been limited owing to mTOR-inhibitor- related toxicities. Unique attributes of mTOR inhibitors include reduced rates of squamous cell carcinoma and cytomegalovirus infection compared to other regimens. As understanding of the mechanisms by which mTORC1 and mTORC2 drive the pathogenesis of renal disease progresses, clinical studies of mTOR pathway targeting will enable testing of evolving hypotheses.
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45
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Grahammer F, Ramakrishnan SK, Rinschen MM, Larionov AA, Syed M, Khatib H, Roerden M, Sass JO, Helmstaedter M, Osenberg D, Kühne L, Kretz O, Wanner N, Jouret F, Benzing T, Artunc F, Huber TB, Theilig F. mTOR Regulates Endocytosis and Nutrient Transport in Proximal Tubular Cells. J Am Soc Nephrol 2016; 28:230-241. [PMID: 27297946 DOI: 10.1681/asn.2015111224] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 05/14/2016] [Indexed: 01/03/2023] Open
Abstract
Renal proximal tubular cells constantly recycle nutrients to ensure minimal loss of vital substrates into the urine. Although most of the transport mechanisms have been discovered at the molecular level, little is known about the factors regulating these processes. Here, we show that mTORC1 and mTORC2 specifically and synergistically regulate PTC endocytosis and transport processes. Using a conditional mouse genetic approach to disable nonredundant subunits of mTORC1, mTORC2, or both, we showed that mice lacking mTORC1 or mTORC1/mTORC2 but not mTORC2 alone develop a Fanconi-like syndrome of glucosuria, phosphaturia, aminoaciduria, low molecular weight proteinuria, and albuminuria. Interestingly, proteomics and phosphoproteomics of freshly isolated kidney cortex identified either reduced expression or loss of phosphorylation at critical residues of different classes of specific transport proteins. Functionally, this resulted in reduced nutrient transport and a profound perturbation of the endocytic machinery, despite preserved absolute expression of the main scavenger receptors, MEGALIN and CUBILIN. Our findings highlight a novel mTOR-dependent regulatory network for nutrient transport in renal proximal tubular cells.
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Affiliation(s)
- Florian Grahammer
- Department of Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Suresh K Ramakrishnan
- Institute of Anatomy, Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Markus M Rinschen
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Alexey A Larionov
- Institute of Anatomy, Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Maryam Syed
- Institute of Anatomy, Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Hazim Khatib
- Department of Medical IV, Sektion Nieren- und Hochdruckkrankheiten, University of Tübingen, Tübingen, Germany
| | - Malte Roerden
- Department of Medical IV, Sektion Nieren- und Hochdruckkrankheiten, University of Tübingen, Tübingen, Germany
| | - Jörn Oliver Sass
- Bioanalytics and Biochemistry, Department of Natural Sciences, Bonn Rhein Sieg University of Applied Sciences, Rheinbach, Germany.,Division of Clinical Chemistry and Biochemistry and Children's Research Centre, University Children's Hospital Zürich, Zurich, Switzerland
| | - Martin Helmstaedter
- Department of Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Dorothea Osenberg
- Department of Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Lucas Kühne
- Department of Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Oliver Kretz
- Department of Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Nicola Wanner
- Department of Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Francois Jouret
- Groupe Interdisciplinaire de Génoprotéomique Appliquée, Cardiovascular Sciences, University of Liège, Liege, Belgium; and
| | - Thomas Benzing
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Ferruh Artunc
- Department of Medical IV, Sektion Nieren- und Hochdruckkrankheiten, University of Tübingen, Tübingen, Germany
| | - Tobias B Huber
- Department of Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany; .,BIOSS, Centre for Biological Signalling Studies and.,FRIAS, Freiburg Institute for Advanced Studies and ZBSA, Center for Biological System Analysis, Albert Ludwigs University of Freiburg, Freiburg, Germany
| | - Franziska Theilig
- Institute of Anatomy, Department of Medicine, University of Fribourg, Fribourg, Switzerland;
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46
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Cotter K, Stransky L, McGuire C, Forgac M. Recent Insights into the Structure, Regulation, and Function of the V-ATPases. Trends Biochem Sci 2016; 40:611-622. [PMID: 26410601 DOI: 10.1016/j.tibs.2015.08.005] [Citation(s) in RCA: 211] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 08/06/2015] [Accepted: 08/07/2015] [Indexed: 10/23/2022]
Abstract
The vacuolar (H(+))-ATPases (V-ATPases) are ATP-dependent proton pumps that acidify intracellular compartments and are also present at the plasma membrane. They function in such processes as membrane traffic, protein degradation, virus and toxin entry, bone resorption, pH homeostasis, and tumor cell invasion. V-ATPases are large multisubunit complexes, composed of an ATP-hydrolytic domain (V1) and a proton translocation domain (V0), and operate by a rotary mechanism. This review focuses on recent insights into their structure and mechanism, the mechanisms that regulate V-ATPase activity (particularly regulated assembly and trafficking), and the role of V-ATPases in processes such as cell signaling and cancer. These developments have highlighted the potential of V-ATPases as a therapeutic target in a variety of human diseases.
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Affiliation(s)
- Kristina Cotter
- Program in Cellular and Molecular Physiology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
| | - Laura Stransky
- Program in Cellular and Molecular Physiology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
| | - Christina McGuire
- Program in Biochemistry, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
| | - Michael Forgac
- Program in Cellular and Molecular Physiology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA; Program in Biochemistry, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA; Department of Developmental, Molecular, and Chemical Biology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA.
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47
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Satoh N, Yamada H, Yamazaki O, Suzuki M, Nakamura M, Suzuki A, Ashida A, Yamamoto D, Kaku Y, Sekine T, Seki G, Horita S. A pure chloride channel mutant of CLC-5 causes Dent's disease via insufficient V-ATPase activation. Pflugers Arch 2016; 468:1183-1196. [PMID: 27044412 DOI: 10.1007/s00424-016-1808-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Revised: 02/02/2016] [Accepted: 03/08/2016] [Indexed: 01/22/2023]
Abstract
Dent's disease is characterized by defective endocytosis in renal proximal tubules (PTs) and caused by mutations in the 2Cl(-)/H(+) exchanger, CLC-5. However, the pathological role of endosomal acidification in endocytosis has recently come into question. To clarify the mechanism of pathogenesis for Dent's disease, we examined the effects of a novel gating glutamate mutation, E211Q, on CLC-5 functions and endosomal acidification. In Xenopus oocytes, wild-type (WT) CLC-5 showed outward-rectifying currents that were inhibited by extracellular acidosis, but E211Q and an artificial pure Cl(-) channel mutant, E211A, showed linear currents that were insensitive to extracellular acidosis. Moreover, depolarizing pulse trains induced a robust reduction in the surface pH of oocytes expressing WT CLC-5 but not E211Q or E211A, indicating that the E211Q mutant functions as a pure Cl(-) channel similar to E211A. In HEK293 cells, E211A and E211Q stimulated endosomal acidification and hypotonicity-inducible vacuolar-type H(+)-ATPase (V-ATPase) activation at the plasma membrane. However, the stimulatory effects of these mutants were reduced compared with WT CLC-5. Furthermore, gene silencing experiments confirmed the functional coupling between V-ATPase and CLC-5 at the plasma membrane of isolated mouse PTs. These results reveal for the first time that the conversion of CLC-5 from a 2Cl(-)/H(+) exchanger into a Cl(-) channel induces Dent's disease in humans. In addition, defective endosomal acidification as a result of insufficient V-ATPase activation may still be important in the pathogenesis of Dent's disease.
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Affiliation(s)
- Nobuhiko Satoh
- Department of Internal Medicine, Faculty of Medicine, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Hideomi Yamada
- Department of Internal Medicine, Faculty of Medicine, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Osamu Yamazaki
- Apheresis and Dialysis Center, General Medicine, School of Medicine, Keio University, Tokyo, Japan
| | - Masashi Suzuki
- Department of Internal Medicine, Faculty of Medicine, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Motonobu Nakamura
- Department of Internal Medicine, Faculty of Medicine, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Atsushi Suzuki
- Department of Internal Medicine, Faculty of Medicine, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Akira Ashida
- Department of Pediatrics, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Daisuke Yamamoto
- Biomedical Computation Center, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Yoshitsugu Kaku
- Department of Nephrology, Fukuoka Children's Hospital, Fukuoka, Japan
| | - Takashi Sekine
- Department of Pediatrics, Ohashi Medical Center, Toho University, Meguro-ku, Tokyo, Japan
| | | | - Shoko Horita
- Department of Internal Medicine, Faculty of Medicine, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
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48
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Trepiccione F, Gerber SD, Grahammer F, López-Cayuqueo KI, Baudrie V, Păunescu TG, Capen DE, Picard N, Alexander RT, Huber TB, Chambrey R, Brown D, Houillier P, Eladari D, Simons M. Renal Atp6ap2/(Pro)renin Receptor Is Required for Normal Vacuolar H+-ATPase Function but Not for the Renin-Angiotensin System. J Am Soc Nephrol 2016; 27:3320-3330. [PMID: 27044666 DOI: 10.1681/asn.2015080915] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 02/24/2016] [Indexed: 01/22/2023] Open
Abstract
ATPase H+-transporting lysosomal accessory protein 2 (Atp6ap2), also known as the (pro)renin receptor, is a type 1 transmembrane protein and an accessory subunit of the vacuolar H+-ATPase (V-ATPase) that may also function within the renin-angiotensin system. However, the contribution of Atp6ap2 to renin-angiotensin-dependent functions remains unconfirmed. Using mice with an inducible conditional deletion of Atp6ap2 in mouse renal epithelial cells, we found that decreased V-ATPase expression and activity in the intercalated cells of the collecting duct impaired acid-base regulation by the kidney. In addition, these mice suffered from marked polyuria resistant to desmopressin administration. Immunoblotting revealed downregulation of the medullary Na+-K+-2Cl- cotransporter NKCC2 in these mice compared with wild-type mice, an effect accompanied by a hypotonic medullary interstitium and impaired countercurrent multiplication. This phenotype correlated with strong autophagic defects in epithelial cells of medullary tubules. Notably, cells with high accumulation of the autophagosomal substrate p62 displayed the strongest reduction of NKCC2 expression. Finally, nephron-specific Atp6ap2 depletion did not affect angiotensin II production, angiotensin II-dependent BP regulation, or sodium handling in the kidney. Taken together, our results show that nephron-specific deletion of Atp6ap2 does not affect the renin-angiotensin system but causes a combination of renal concentration defects and distal renal tubular acidosis as a result of impaired V-ATPase activity.
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Affiliation(s)
- Francesco Trepiccione
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche_S970, Paris Centre de Recherche Cardiovasculaire, Hôpital Européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France.,Department of Cardio-Thoracic and Respiratory Science, Second University of Naples, Caserta, Italy
| | - Simon D Gerber
- Imagine Institute, Paris Descartes University-Sorbonne Paris Cité, Paris, France
| | - Florian Grahammer
- Renal Division, University Medical Center Freiburg, Freiburg, Germany
| | - Karen I López-Cayuqueo
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche_S970, Paris Centre de Recherche Cardiovasculaire, Hôpital Européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France.,Centro de Estudios Científicos, Valdivia, Chile
| | - Véronique Baudrie
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche_S970, Paris Centre de Recherche Cardiovasculaire, Hôpital Européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Teodor G Păunescu
- Program in Membrane Biology/Nephrology Division, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts
| | - Diane E Capen
- Program in Membrane Biology/Nephrology Division, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts
| | - Nicolas Picard
- Centre National de la Recherche Scientifique Equipe de Recherche Labelisée 8228, Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche_S1138, Centre de Recherche des Cordeliers, Université Pierre et Marie Curie, Paris, France
| | - R Todd Alexander
- Department of Pediatrics, University of Alberta, Edmonton, Canada; and
| | - Tobias B Huber
- Renal Division, University Medical Center Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Regine Chambrey
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche_S970, Paris Centre de Recherche Cardiovasculaire, Hôpital Européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Dennis Brown
- Program in Membrane Biology/Nephrology Division, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts
| | - Pascal Houillier
- Program in Membrane Biology/Nephrology Division, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts
| | - Dominique Eladari
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche_S970, Paris Centre de Recherche Cardiovasculaire, Hôpital Européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France;
| | - Matias Simons
- Imagine Institute, Paris Descartes University-Sorbonne Paris Cité, Paris, France;
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Role of the mammalian target of rapamycin pathway in lentiviral vector transduction of hematopoietic stem cells. Curr Opin Hematol 2016; 22:302-8. [PMID: 26049750 DOI: 10.1097/moh.0000000000000150] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
PURPOSE OF REVIEW A major goal in repopulating hematopoietic stem cell (HSC) gene therapies is achieving high-efficacy gene transfer, while maintaining robust HSC engraftment and differentiation in vivo. Recent studies have documented that rapamycin treatment of HSC during lentiviral vector transduction enhances gene transfer to human and mouse HSCs and maintains engraftment capacity. In this review, we place into context the role of mammalian target of rapamycin (mTOR) pathways in HSC quiescence and function, endocytic regulation, and lentiviral gene delivery. RECENT FINDINGS Lentiviral vector transduction of human and mouse HSCs is considerably enhanced by rapamycin treatment. Furthermore, rapamycin preserves long-term engraftment of human and mouse HSCs. Investigations of cellular mechanisms that contribute to increased transduction in HSCs uncover a role for mTOR inhibition-dependent activation of endocytosis. SUMMARY Rapamycin enhances lentiviral vector transduction of HSCs through regulation of endocytic activity via mTOR inhibition. An important attribute of rapamycin treatment during transduction is the preservation of HSC function, allowing reconstitution of long-term hematopoiesis in vivo in murine models.
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50
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Tognon E, Kobia F, Busi I, Fumagalli A, De Masi F, Vaccari T. Control of lysosomal biogenesis and Notch-dependent tissue patterning by components of the TFEB-V-ATPase axis in Drosophila melanogaster. Autophagy 2016; 12:499-514. [PMID: 26727288 PMCID: PMC4836007 DOI: 10.1080/15548627.2015.1134080] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
In vertebrates, TFEB (transcription factor EB) and MITF (microphthalmia-associated transcription factor) family of basic Helix-Loop-Helix (bHLH) transcription factors regulates both lysosomal function and organ development. However, it is not clear whether these 2 processes are interconnected. Here, we show that Mitf, the single TFEB and MITF ortholog in Drosophila, controls expression of vacuolar-type H(+)-ATPase pump (V-ATPase) subunits. Remarkably, we also find that expression of Vha16-1 and Vha13, encoding 2 key components of V-ATPase, is patterned in the wing imaginal disc. In particular, Vha16-1 expression follows differentiation of proneural regions of the disc. These regions, which will form sensory organs in the adult, appear to possess a distinctive endolysosomal compartment and Notch (N) localization. Modulation of Mitf activity in the disc in vivo alters endolysosomal function and disrupts proneural patterning. Similar to our findings in Drosophila, in human breast epithelial cells we observe that impairment of the Vha16-1 human ortholog ATP6V0C changes the size and function of the endolysosomal compartment and that depletion of TFEB reduces ligand-independent N signaling activity. Our data suggest that lysosomal-associated functions regulated by the TFEB-V-ATPase axis might play a conserved role in shaping cell fate.
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Affiliation(s)
- Emiliana Tognon
- a IFOM - FIRC Institute of Molecular Oncology , Milan , Italy
| | - Francis Kobia
- a IFOM - FIRC Institute of Molecular Oncology , Milan , Italy
| | - Ilaria Busi
- a IFOM - FIRC Institute of Molecular Oncology , Milan , Italy
| | | | - Federico De Masi
- b Center for Biological Sequence Analysis, Institute for Systems Biology, Technical University of Denmark , Lyngby , Denmark
| | - Thomas Vaccari
- a IFOM - FIRC Institute of Molecular Oncology , Milan , Italy
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