1
|
Das F, Ghosh-Choudhury N, Kasinath BS, Sharma K, Choudhury GG. High glucose-induced downregulation of PTEN-Long is sufficient for proximal tubular cell injury in diabetic kidney disease. Exp Cell Res 2024; 440:114116. [PMID: 38830568 DOI: 10.1016/j.yexcr.2024.114116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 04/24/2024] [Accepted: 05/31/2024] [Indexed: 06/05/2024]
Abstract
During the progression of diabetic kidney disease, proximal tubular epithelial cells respond to high glucose to induce hypertrophy and matrix expansion leading to renal fibrosis. Recently, a non-canonical PTEN has been shown to be translated from an upstream initiation codon CUG (leucine) to produce a longer protein called PTEN-Long (PTEN-L). Interestingly, the extended sequence present in PTEN-L contains cell secretion/penetration signal. Role of this non-canonical PTEN-L in diabetic renal tubular injury is not known. We show that high glucose decreases expression of PTEN-L. As a mechanism of its function, we find that reduced PTEN-L activates Akt-2, which phosphorylates and inactivate tuberin and PRAS40, resulting in activation of mTORC1 in tubular cells. Antibacterial agent acriflavine and antiviral agent ATA regulate translation from CUG codon. Acriflavine and ATA, respectively, decreased and increased expression of PTEN-L to altering Akt-2 and mTORC1 activation in the absence of change in expression of canonical PTEN. Consequently, acriflavine and ATA modulated high glucose-induced tubular cell hypertrophy and lamininγ1 expression. Importantly, expression of PTEN-L inhibited high glucose-stimulated Akt/mTORC1 activity to abrogate these processes. Since PTEN-L contains secretion/penetration signals, addition of conditioned medium containing PTEN-L blocked Akt-2/mTORC1 activity. Notably, in renal cortex of diabetic mice, we found reduced PTEN-L concomitant with Akt-2/mTORC1 activation, leading to renal hypertrophy and lamininγ1 expression. These results present first evidence for involvement of PTEN-L in diabetic kidney disease.
Collapse
Affiliation(s)
- Falguni Das
- VA Research, TX, USA; Department of Medicine, TX, USA
| | | | | | - Kumar Sharma
- VA Research, TX, USA; Department of Medicine, TX, USA
| | - Goutam Ghosh Choudhury
- VA Research, TX, USA; Department of Medicine, TX, USA; Geriatric Research, Education and Clinical Center, South Texas Veterans Health Care System, San Antonio, TX, USA.
| |
Collapse
|
2
|
Espartero A, Vidal A, Lopez I, Raya AI, Rodriguez M, Aguilera-Tejero E, Pineda C. Rapamycin downregulates α-klotho in the kidneys of female rats with normal and reduced renal function. PLoS One 2023; 18:e0294791. [PMID: 38015969 PMCID: PMC10684065 DOI: 10.1371/journal.pone.0294791] [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: 09/06/2023] [Accepted: 11/07/2023] [Indexed: 11/30/2023] Open
Abstract
Both mTOR and α-klotho play a role in the pathophysiology of renal disease, influence mineral metabolism and participate in the aging process. The influence of mTOR inhibition by rapamycin on renal α-klotho expression is unknown. Rats with normal (controls) and reduced (Nx) renal function were treated with rapamycin, 1.3 mg/kg/day, for 22 days. The experiments were conducted with rats fed 0.6% P diet (NP) and 0.2% P diet (LP). Treatment with rapamycin promoted phosphaturia in control and Nx rats fed NP and LP. A decrease in FGF23 was identified in controls after treatment with rapamycin. In rats fed NP, rapamycin decreased mRNA α-klotho/GADPH ratio both in controls, 0.6±0.1 vs 1.1±0.1, p = 0.001, and Nx, 0.3±0.1 vs 0.7±0.1, p = 0.01. At the protein level, a significant reduction in α-klotho was evidenced after treatment with rapamycin both by Western Blot: 0.6±0.1 vs 1.0±0.1, p = 0.01, in controls, 0.7±0.1 vs 1.1±0.1, p = 0.02, in Nx; and by immunohistochemistry staining. Renal α-klotho was inversely correlated with urinary P excretion (r = -0.525, p = 0.0002). The decrease in α-klotho after treatment with rapamycin was also observed in rats fed LP. In conclusion, rapamycin increases phosphaturia and down-regulates α-klotho expression in rats with normal and decreased renal function. These effects can be observed in animals ingesting normal and low P diet.
Collapse
Affiliation(s)
- Azahara Espartero
- Department of Animal Medicine and Surgery, University of Cordoba, Campus Universitario Rabanales, Cordoba, Spain
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
| | - Angela Vidal
- Department of Animal Medicine and Surgery, University of Cordoba, Campus Universitario Rabanales, Cordoba, Spain
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
| | - Ignacio Lopez
- Department of Animal Medicine and Surgery, University of Cordoba, Campus Universitario Rabanales, Cordoba, Spain
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
| | - Ana I. Raya
- Department of Animal Medicine and Surgery, University of Cordoba, Campus Universitario Rabanales, Cordoba, Spain
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
| | - Mariano Rodriguez
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
| | - Escolastico Aguilera-Tejero
- Department of Animal Medicine and Surgery, University of Cordoba, Campus Universitario Rabanales, Cordoba, Spain
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
| | - Carmen Pineda
- Department of Animal Medicine and Surgery, University of Cordoba, Campus Universitario Rabanales, Cordoba, Spain
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
| |
Collapse
|
3
|
Huynh C, Ryu J, Lee J, Inoki A, Inoki K. Nutrient-sensing mTORC1 and AMPK pathways in chronic kidney diseases. Nat Rev Nephrol 2023; 19:102-122. [PMID: 36434160 DOI: 10.1038/s41581-022-00648-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2022] [Indexed: 11/27/2022]
Abstract
Nutrients such as glucose, amino acids and lipids are fundamental sources for the maintenance of essential cellular processes and homeostasis in all organisms. The nutrient-sensing kinases mechanistic target of rapamycin (mTOR) and AMP-activated protein kinase (AMPK) are expressed in many cell types and have key roles in the control of cell growth, proliferation, differentiation, metabolism and survival, ultimately contributing to the physiological development and functions of various organs, including the kidney. Dysregulation of these kinases leads to many human health problems, including cancer, neurodegenerative diseases, metabolic disorders and kidney diseases. In the kidney, physiological levels of mTOR and AMPK activity are required to support kidney cell growth and differentiation and to maintain kidney cell integrity and normal nephron function, including transport of electrolytes, water and glucose. mTOR forms two functional multi-protein kinase complexes, mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). Hyperactivation of mTORC1 leads to podocyte and tubular cell dysfunction and vulnerability to injury, thereby contributing to the development of chronic kidney diseases, including diabetic kidney disease, obesity-related kidney disease and polycystic kidney disease. Emerging evidence suggests that targeting mTOR and/or AMPK could be an effective therapeutic approach to controlling or preventing these diseases.
Collapse
Affiliation(s)
- Christopher Huynh
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.,Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Jaewhee Ryu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Jooho Lee
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Ayaka Inoki
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA.,Department of Internal Medicine, Division of Nephrology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Ken Inoki
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA. .,Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA. .,Department of Internal Medicine, Division of Nephrology, University of Michigan Medical School, Ann Arbor, MI, USA.
| |
Collapse
|
4
|
Abou Daher A, Alkhansa S, Azar WS, Rafeh R, Ghadieh HE, Eid AA. Translational Aspects of the Mammalian Target of Rapamycin Complexes in Diabetic Nephropathy. Antioxid Redox Signal 2022; 37:802-819. [PMID: 34544257 DOI: 10.1089/ars.2021.0217] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Significance: Despite the many efforts put into understanding diabetic nephropathy (DN), direct treatments for DN have yet to be discovered. Understanding the mechanisms behind DN is an essential step in the development of novel therapeutic regimens. The mammalian target of rapamycin (mTOR) pathway has emerged as an important candidate in the quest for drug discovery because of its role in regulating growth, proliferation, as well as protein and lipid metabolism. Recent Advances: Kidney cells have been found to rely on basal autophagy for survival and for conserving kidney integrity. Recent studies have shown that diabetes induces renal autophagy deregulation, leading to kidney injury. Hyper-activation of the mTOR pathway and oxidative stress have been suggested to play a role in diabetes-induced autophagy imbalance. Critical Issues: A detailed understanding of the role of mTOR signaling in diabetes-associated complications is of major importance in the search for a cure. In this review, we provide evidence that mTOR is heavily implicated in diabetes-induced kidney injury. We suggest possible mechanisms through which mTOR exerts its negative effects by increasing insulin resistance, upregulating oxidative stress, and inhibiting autophagy. Future Directions: Both increased oxidative stress and autophagy deregulation are deeply embedded in DN. However, the mechanisms controlling oxidative stress and autophagy are not well understood. Although Akt/mTOR signaling seems to play an important role in oxidative stress and autophagy, further investigation is required to uncover the details of this signaling pathway. Antioxid. Redox Signal. 37, 802-819.
Collapse
Affiliation(s)
- Alaa Abou Daher
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine and Medical Center, American University of Beirut, Beirut, Lebanon
| | - Sahar Alkhansa
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine and Medical Center, American University of Beirut, Beirut, Lebanon.,AUB Diabetes, Faculty of Medicine and Medical Center, American University of Beirut, Beirut, Lebanon
| | - William S Azar
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine and Medical Center, American University of Beirut, Beirut, Lebanon.,AUB Diabetes, Faculty of Medicine and Medical Center, American University of Beirut, Beirut, Lebanon.,Department of Physiology and Biophysics, Georgetown University Medical School, Washington, District of Columbia, USA
| | - Rim Rafeh
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine and Medical Center, American University of Beirut, Beirut, Lebanon.,AUB Diabetes, Faculty of Medicine and Medical Center, American University of Beirut, Beirut, Lebanon
| | - Hilda E Ghadieh
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine and Medical Center, American University of Beirut, Beirut, Lebanon.,AUB Diabetes, Faculty of Medicine and Medical Center, American University of Beirut, Beirut, Lebanon
| | - Assaad A Eid
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine and Medical Center, American University of Beirut, Beirut, Lebanon.,AUB Diabetes, Faculty of Medicine and Medical Center, American University of Beirut, Beirut, Lebanon
| |
Collapse
|
5
|
High glucose-stimulated enhancer of zeste homolog-2 (EZH2) forces suppression of deptor to cause glomerular mesangial cell pathology. Cell Signal 2021; 86:110072. [PMID: 34224844 DOI: 10.1016/j.cellsig.2021.110072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/23/2021] [Accepted: 06/29/2021] [Indexed: 11/24/2022]
Abstract
Function of mTORC1 and mTORC2 has emerged as a driver of mesangial cell pathologies in diabetic nephropathy. The mechanism of mTOR activation is poorly understood in this disease. Deptor is a constitutive subunit and a negative regulator of both mTOR complexes. Mechanistic investigation in mesangial cells revealed that high glucose decreased the expression of deptor concomitant with increased mTORC1 and mTORC2 activities, induction of hypertrophy and, expression of fibronectin and PAI-1. shRNAs against deptor mimicked these pathologic outcomes of high glucose. Conversely, overexpression of deptor significantly inhibited all effects of high glucose. To determine the mechanism of deptor suppression, we found that high glucose significantly increased the expression of EZH2, resulting in lysine-27 tri-methylation of histone H3 (H3K27Me3). Employing approaches including pharmacological inhibition, shRNA-mediated downregulation and overexpression of EZH2, we found that EZH2 regulates high glucose-induced deptor suppression along with activation of mTOR, mesangial cell hypertrophy and fibronectin/PAI-1 expression. Moreover, expression of hyperactive mTORC1 reversed shEZH2-mediated inhibition of hypertrophy and expression of fibronectin and PAI-1 by high glucose. Finally, in renal cortex of diabetic mice, we found that enhanced expression of EZH2 is associated with decreased deptor levels and increased mTOR activity and, expression of fibronectin and PAI-1. Together, our findings provide a novel mechanism for mTOR activation via EZH2 to induce mesangial cell hypertrophy and matrix expansion during early progression of diabetic nephropathy. These results suggest a strategy for leveraging the intrinsic effect of deptor to suppress mTOR activity via reducing EZH2 as a novel therapy for diabetic nephropathy.
Collapse
|
6
|
Podocyte Lysosome Dysfunction in Chronic Glomerular Diseases. Int J Mol Sci 2020; 21:ijms21051559. [PMID: 32106480 PMCID: PMC7084483 DOI: 10.3390/ijms21051559] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 02/24/2020] [Accepted: 02/24/2020] [Indexed: 02/06/2023] Open
Abstract
Podocytes are visceral epithelial cells covering the outer surface of glomerular capillaries in the kidney. Blood is filtered through the slit diaphragm of podocytes to form urine. The functional and structural integrity of podocytes is essential for the normal function of the kidney. As a membrane-bound organelle, lysosomes are responsible for the degradation of molecules via hydrolytic enzymes. In addition to its degradative properties, recent studies have revealed that lysosomes may serve as a platform mediating cellular signaling in different types of cells. In the last decade, increasing evidence has revealed that the normal function of the lysosome is important for the maintenance of podocyte homeostasis. Podocytes have no ability to proliferate under most pathological conditions; therefore, lysosome-dependent autophagic flux is critical for podocyte survival. In addition, new insights into the pathogenic role of lysosome and associated signaling in podocyte injury and chronic kidney disease have recently emerged. Targeting lysosomal functions or signaling pathways are considered potential therapeutic strategies for some chronic glomerular diseases. This review briefly summarizes current evidence demonstrating the regulation of lysosomal function and signaling mechanisms as well as the canonical and noncanonical roles of podocyte lysosome dysfunction in the development of chronic glomerular diseases and associated therapeutic strategies.
Collapse
|
7
|
Sakai S, Yamamoto T, Takabatake Y, Takahashi A, Namba-Hamano T, Minami S, Fujimura R, Yonishi H, Matsuda J, Hesaka A, Matsui I, Matsusaka T, Niimura F, Yanagita M, Isaka Y. Proximal Tubule Autophagy Differs in Type 1 and 2 Diabetes. J Am Soc Nephrol 2019; 30:929-945. [PMID: 31040190 DOI: 10.1681/asn.2018100983] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 02/22/2019] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Evidence of a protective role of autophagy in kidney diseases has sparked interest in autophagy as a potential therapeutic strategy. However, understanding how the autophagic process is altered in each disorder is critically important in working toward therapeutic applications. METHODS Using cultured kidney proximal tubule epithelial cells (PTECs) and diabetic mouse models, we investigated how autophagic activity differs in type 1 versus type 2 diabetic nephropathy. We explored nutrient signals regulating starvation-induced autophagy in PTECs and used autophagy-monitoring mice and PTEC-specific autophagy-deficient knockout mice to examine differences in autophagy status and autophagy's role in PTECs in streptozotocin (STZ)-treated type 1 and db/db type 2 diabetic nephropathy. We also examined the effects of rapamycin (an inhibitor of mammalian target of rapamycin [mTOR]) on vulnerability to ischemia-reperfusion injury. RESULTS Administering insulin or amino acids, but not glucose, suppressed autophagy by activating mTOR signaling. In db/db mice, autophagy induction was suppressed even under starvation; in STZ-treated mice, autophagy was enhanced even under fed conditions but stagnated under starvation due to lysosomal stress. Using knockout mice with diabetes, we found that, in STZ-treated mice, activated autophagy counteracts mitochondrial damage and fibrosis in the kidneys, whereas in db/db mice, autophagic suppression jeopardizes kidney even in the autophagy-competent state. Rapamycin-induced pharmacologic autophagy produced opposite effects on ischemia-reperfusion injury in STZ-treated and db/db mice. CONCLUSIONS Autophagic activity in PTECs is mainly regulated by insulin. Consequently, autophagic activity differs in types 1 and 2 diabetic nephropathy, which should be considered when developing strategies to treat diabetic nephropathy by modulating autophagy.
Collapse
Affiliation(s)
- Shinsuke Sakai
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Takeshi Yamamoto
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yoshitsugu Takabatake
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan;
| | - Atsushi Takahashi
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Tomoko Namba-Hamano
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Satoshi Minami
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Ryuta Fujimura
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Hiroaki Yonishi
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Jun Matsuda
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Atsushi Hesaka
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Isao Matsui
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Taiji Matsusaka
- Institute of Medical Sciences and Department of Basic Medicine and
| | - Fumio Niimura
- Department of Pediatrics, Tokai University School of Medicine, Kanagawa, Japan
| | - Motoko Yanagita
- Department of Nephrology, Kyoto University Graduate School of Medicine, Kyoto, Japan; and.,Institute for the Advanced Study of Human Biology, Kyoto University, Kyoto, Japan
| | - Yoshitaka Isaka
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| |
Collapse
|
8
|
Paoletti E, Citterio F, Corsini A, Potena L, Rigotti P, Sandrini S, Bussalino E, Stallone G. Everolimus in kidney transplant recipients at high cardiovascular risk: a narrative review. J Nephrol 2019; 33:69-82. [DOI: 10.1007/s40620-019-00609-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 04/05/2019] [Indexed: 12/20/2022]
|
9
|
Canaud G, Brooks CR, Kishi S, Taguchi K, Nishimura K, Magassa S, Scott A, Hsiao LL, Ichimura T, Terzi F, Yang L, Bonventre JV. Cyclin G1 and TASCC regulate kidney epithelial cell G 2-M arrest and fibrotic maladaptive repair. Sci Transl Med 2019; 11:11/476/eaav4754. [PMID: 30674655 PMCID: PMC6527117 DOI: 10.1126/scitranslmed.aav4754] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 12/20/2018] [Indexed: 12/11/2022]
Abstract
Fibrosis contributes to the progression of chronic kidney disease (CKD). Severe acute kidney injury can lead to CKD through proximal tubular cell (PTC) cycle arrest in the G2-M phase, with secretion of profibrotic factors. Here, we show that epithelial cells in the G2-M phase form target of rapamycin (TOR)-autophagy spatial coupling compartments (TASCCs), which promote profibrotic secretion similar to the senescence-associated secretory phenotype. Cyclin G1 (CG1), an atypical cyclin, promoted G2-M arrest in PTCs and up-regulated TASCC formation. PTC TASCC formation was also present in humans with CKD. Prevention of TASCC formation in cultured PTCs blocked secretion of profibrotic factors. PTC-specific knockout of a key TASCC component reduced the rate of kidney fibrosis progression in mice with CKD. CG1 induction and TASCC formation also occur in liver fibrosis. Deletion of CG1 reduced G2-M phase cells and TASCC formation in vivo. This study provides mechanistic evidence supporting how profibrotic G2-M arrest is induced in kidney injury and how G2-M-arrested PTCs promote fibrosis, identifying new therapeutic targets to mitigate kidney fibrosis.
Collapse
Affiliation(s)
- Guillaume Canaud
- Renal Division, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
- INSERM U1151, Institut Necker-Enfants Malades, Université Paris Descartes, Paris 75743, France
- Service de Néphrologie et Transplantation Adultes, Hôpital Necker-Enfants Malades, Paris 75743, France
| | - Craig R Brooks
- Renal Division, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Seiji Kishi
- Renal Division, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
- Department of Nephrology, Graduate School of Biomedical Sciences, Tokushima University, Tokushima 7708503, Japan
| | - Kensei Taguchi
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Kenji Nishimura
- Department of Nephrology, Graduate School of Biomedical Sciences, Tokushima University, Tokushima 7708503, Japan
| | - Sato Magassa
- INSERM U1151, Institut Necker-Enfants Malades, Université Paris Descartes, Paris 75743, France
| | - Adam Scott
- Renal Division, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Li-Li Hsiao
- Renal Division, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Takaharu Ichimura
- Renal Division, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Fabiola Terzi
- INSERM U1151, Institut Necker-Enfants Malades, Université Paris Descartes, Paris 75743, France
| | - Li Yang
- Renal Division, Peking University First Hospital, Beijing 100871, China
| | - Joseph V Bonventre
- Renal Division, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA 02115, USA.
- Division of Health Sciences and Technology, Harvard-Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Harvard Stem Cell Institute, Cambridge, MA 02138, USA
| |
Collapse
|
10
|
A/L B Vasanth Rao VR, Tan SH, Candasamy M, Bhattamisra SK. Diabetic nephropathy: An update on pathogenesis and drug development. Diabetes Metab Syndr 2019; 13:754-762. [PMID: 30641802 DOI: 10.1016/j.dsx.2018.11.054] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 11/29/2018] [Indexed: 01/08/2023]
Abstract
Diabetic nephropathy (DN) is a major cause of end-stage renal disease and affects a large number of individuals with diabetes. However, the development of specific treatments for DN has not yet been identified. Hence, this review is concisely designed to understand the molecular pathways leading to DN in order to develop suitable therapeutic strategies. Extensive literature search have been carried in regard with the pathogenesis and pathophysiology of DN, drug targets and updates on clinical trials, the consequences associated with DN and the potential biomarkers for diagnosis and prediction of DN are discussed in this review. DN is characterised by microalbuminuria and macroalbuminuria, and morphological changes such as glomerular thickening, interstitial fibrosis, formation of nodular glomerulosclerosis and decreased endothelial cell fenestration. Besides, the involvement of renin-angiotensin-aldosterone system, inflammation and genetic factors are the key pathways in the progression of DN. In regard with drug development drugs targeted to epidermal growth factor, inflammatory cytokines, ACTH receptor and TGFβ1 receptors are in pipeline for clinical trials whereas, several drugs have also failed in phase III and phase IV of clinical trials due to lack of efficacy and severe adverse effect. The research on DN is limited with respect to its pathogenesis and drug development. Thus, a more detailed understanding of the pathogenesis of DN is very essential to progress in the drug development process.
Collapse
Affiliation(s)
- Vikram Rao A/L B Vasanth Rao
- School of Postgraduate Studies, International Medical University, No 126, Jalan Jalil Perkasa 19, Bukit Jalil, 57000, Kuala Lumpur, Malaysia.
| | - Sean Hong Tan
- School of Pharmacy, International Medical University, No 126, Jalan Jalil Perkasa 19, Bukit Jalil, 57000, Kuala Lumpur, Malaysia.
| | - Mayuren Candasamy
- Department of Life Sciences, School of Pharmacy, International Medical University, No 126, Jalan Jalil Perkasa 19, Bukit Jalil, 57000, Kuala Lumpur, Malaysia.
| | - Subrat Kumar Bhattamisra
- Department of Life Sciences, School of Pharmacy, International Medical University, No 126, Jalan Jalil Perkasa 19, Bukit Jalil, 57000, Kuala Lumpur, Malaysia.
| |
Collapse
|
11
|
Akt2 causes TGFβ-induced deptor downregulation facilitating mTOR to drive podocyte hypertrophy and matrix protein expression. PLoS One 2018; 13:e0207285. [PMID: 30444896 PMCID: PMC6239304 DOI: 10.1371/journal.pone.0207285] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 10/29/2018] [Indexed: 02/06/2023] Open
Abstract
TGFβ promotes podocyte hypertrophy and expression of matrix proteins in fibrotic kidney diseases such as diabetic nephropathy. Both mTORC1 and mTORC2 are hyperactive in response to TGFβ in various renal diseases. Deptor is a component of mTOR complexes and a constitutive inhibitor of their activities. We identified that deptor downregulation by TGFβ maintains hyperactive mTOR in podocytes. To unravel the mechanism, we found that TGFβ -initiated noncanonical signaling controls deptor inhibition. Pharmacological inhibitor of PI 3 kinase, Ly 294002 and pan Akt kinase inhibitor MK 2206 prevented the TGFβ induced downregulation of deptor, resulting in suppression of both mTORC1 and mTORC2 activities. However, specific isoform of Akt involved in this process is not known. We identified Akt2 as predominant isoform expressed in kidney cortex, glomeruli and podocytes. TGFβ time-dependently increased the activating phosphorylation of Akt2. Expression of dominant negative PI 3 kinase and its signaling inhibitor PTEN blocked Akt2 phosphorylation by TGFβ. Inhibition of Akt2 using a phospho-deficient mutant that inactivates its kinase activity, as well as siRNA against the kinase markedly diminished TGFβ -mediated deptor suppression, its association with mTOR and activation of mTORC1 and mTORC2. Importantly, inhibition of Akt2 blocked TGFβ -induced podocyte hypertrophy and expression of the matrix protein fibronectin. This inhibition was reversed by the downregulation of deptor. Interestingly, we detected increased phosphorylation of Akt2 concomitant with TGFβ expression in the kidneys of diabetic rats. Thus, our data identify previously unrecognized Akt2 kinase as a driver of TGFβ induced deptor downregulation and sustained mTORC1 and mTORC2 activation. Furthermore, we provide the first evidence that deptor downstream of Akt2 contributes to podocyte hypertrophy and matrix protein expression found in glomerulosclerosis in different renal diseases.
Collapse
|
12
|
Therapeutic Use of mTOR Inhibitors in Renal Diseases: Advances, Drawbacks, and Challenges. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:3693625. [PMID: 30510618 PMCID: PMC6231362 DOI: 10.1155/2018/3693625] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 09/07/2018] [Accepted: 09/25/2018] [Indexed: 02/06/2023]
Abstract
The mammalian (or mechanistic) target of rapamycin (mTOR) pathway has a key role in the regulation of a variety of biological processes pivotal for cellular life, aging, and death. Impaired activity of mTOR complexes (mTORC1/mTORC2), particularly mTORC1 overactivation, has been implicated in a plethora of age-related disorders, including human renal diseases. Since the discovery of rapamycin (or sirolimus), more than four decades ago, advances in our understanding of how mTOR participates in renal physiological and pathological mechanisms have grown exponentially, due to both preclinical studies in animal models with genetic modification of some mTOR components as well as due to evidence coming from the clinical experience. The main clinical indication of rapamycin is as immunosuppressive therapy for the prevention of allograft rejection, namely, in renal transplantation. However, considering the central participation of mTOR in the pathogenesis of other renal disorders, the use of rapamycin and its analogs meanwhile developed (rapalogues) everolimus and temsirolimus has been viewed as a promising pharmacological strategy. This article critically reviews the use of mTOR inhibitors in renal diseases. Firstly, we briefly overview the mTOR components and signaling as well as the pharmacological armamentarium targeting the mTOR pathway currently available or in the research and development stages. Thereafter, we revisit the mTOR pathway in renal physiology to conclude with the advances, drawbacks, and challenges regarding the use of mTOR inhibitors, in a translational perspective, in four classes of renal diseases: kidney transplantation, polycystic kidney diseases, renal carcinomas, and diabetic nephropathy.
Collapse
|
13
|
|
14
|
Maity S, Bera A, Ghosh-Choudhury N, Das F, Kasinath BS, Choudhury GG. microRNA-181a downregulates deptor for TGFβ-induced glomerular mesangial cell hypertrophy and matrix protein expression. Exp Cell Res 2018; 364:5-15. [PMID: 29397070 DOI: 10.1016/j.yexcr.2018.01.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 01/16/2018] [Indexed: 02/06/2023]
Abstract
TGFβ contributes to mesangial cell hypertrophy and matrix protein increase in various kidney diseases including diabetic nephropathy. Deptor is an mTOR-interacting protein and suppresses mTORC1 and mTORC2 activities. We have recently shown that TGFβ-induced inhibition of deptor increases the mTOR activity. The mechanism by which TGFβ regulates deptor expression is not known. Here we identify deptor as a target of the microRNA-181a. We show that in mesangial cells, TGFβ increases the expression of miR-181a to downregulate deptor. Decrease in deptor augments mTORC2 activity, resulting in phosphorylation/activation of Akt kinase. Akt promotes inactivating phosphorylation of PRAS40 and tuberin, leading to stimulation of mTORC1. miR-181a-mimic increased mTORC1 and C2 activities, while anti-miR-181a inhibited them. mTORC1 controls protein synthesis via phosphorylation of translation initiation and elongation suppressors 4EBP-1 and eEF2 kinase. TGFβ-stimulated miR-181a increased the phosphorylation of 4EBP-1 and eEF2 kinase, resulting in their inactivation. miR-181a-dependent inactivation of eEF2 kinase caused dephosphorylation of eEF2. Consequently, miR-181a-mimic increased protein synthesis and hypertrophy of mesangial cells similar to TGFβ. Anti-miR-181a blocked these events in a deptor-dependent manner. Finally, TGFβ-miR-181a-driven deptor downregulation increased the expression of fibronectin. Our results identify a novel mechanism involving miR-181a-driven deptor downregulation, which contributes to mesangial cell pathologies in renal complications.
Collapse
Affiliation(s)
- Soumya Maity
- Department of Medicine, UT Health San Antonio, TX, United States
| | - Amit Bera
- Department of Medicine, UT Health San Antonio, TX, United States
| | - Nandini Ghosh-Choudhury
- VA Biomedical Laboratory Research, South Texas Veterans Health Care System, San Antonio, TX, United States; Department of Pathology, UT Health San Antonio, TX, United States
| | - Falguni Das
- Department of Medicine, UT Health San Antonio, TX, United States; VA Biomedical Laboratory Research, South Texas Veterans Health Care System, San Antonio, TX, United States
| | - Balakuntalam S Kasinath
- Department of Medicine, UT Health San Antonio, TX, United States; VA Biomedical Laboratory Research, South Texas Veterans Health Care System, San Antonio, TX, United States
| | - Goutam Ghosh Choudhury
- Department of Medicine, UT Health San Antonio, TX, United States; VA Biomedical Laboratory Research, South Texas Veterans Health Care System, San Antonio, TX, United States; Geriatric Research, Education and Clinical Research Center, South Texas Veterans Health Care System, San Antonio, TX, United States.
| |
Collapse
|
15
|
Shingarev R, Jaimes EA. Renal cell carcinoma: new insights and challenges for a clinician scientist. Am J Physiol Renal Physiol 2017; 313:F145-F154. [PMID: 28381462 PMCID: PMC5582896 DOI: 10.1152/ajprenal.00480.2016] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 03/22/2017] [Accepted: 03/31/2017] [Indexed: 02/06/2023] Open
Abstract
There is a growing recognition of the complex interplay between renal cell cancer (RCC), kidney function, mechanical reduction of nephron mass, and systemic agents targeting the cancer. Earlier detection of RCC and rising life expectancy of cancer survivors places a greater emphasis on preservation of renal function after cancer resection and during systemic therapy. Unique adverse effects associated with RCC drugs not only help reveal cancer pathophysiology but also expand our knowledge of normal cell signaling and metabolism. In this review, we outline our current understanding of RCC biology and treatment, their bidirectional relationship with kidney function, and unmet research needs in this field.
Collapse
Affiliation(s)
- Roman Shingarev
- Renal Service, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Edgar A Jaimes
- Renal Service, Memorial Sloan-Kettering Cancer Center, New York, New York
| |
Collapse
|
16
|
Jacob S, Nair AB. A review on therapeutic drug monitoring of the mTOR class of immunosuppressants: everolimus and sirolimus. DRUGS & THERAPY PERSPECTIVES 2017. [DOI: 10.1007/s40267-017-0403-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
17
|
Zschiedrich S, Bork T, Liang W, Wanner N, Eulenbruch K, Munder S, Hartleben B, Kretz O, Gerber S, Simons M, Viau A, Burtin M, Wei C, Reiser J, Herbach N, Rastaldi MP, Cohen CD, Tharaux PL, Terzi F, Walz G, Gödel M, Huber TB. Targeting mTOR Signaling Can Prevent the Progression of FSGS. J Am Soc Nephrol 2017; 28:2144-2157. [PMID: 28270414 DOI: 10.1681/asn.2016050519] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 01/16/2017] [Indexed: 01/04/2023] Open
Abstract
Mammalian target of rapamycin (mTOR) signaling is involved in a variety of kidney diseases. Clinical trials administering mTOR inhibitors to patients with FSGS, a prototypic podocyte disease, led to conflicting results, ranging from remission to deterioration of kidney function. Here, we combined complex genetic titration of mTOR complex 1 (mTORC1) levels in murine glomerular disease models, pharmacologic studies, and human studies to precisely delineate the role of mTOR in FSGS. mTORC1 target genes were significantly induced in microdissected glomeruli from both patients with FSGS and a murine FSGS model. Furthermore, a mouse model with constitutive mTORC1 activation closely recapitulated human FSGS. Notably, the complete knockout of mTORC1 by induced deletion of both Raptor alleles accelerated the progression of murine FSGS models. However, lowering mTORC1 signaling by deleting just one Raptor allele ameliorated the progression of glomerulosclerosis. Similarly, low-dose treatment with the mTORC1 inhibitor rapamycin efficiently diminished disease progression. Mechanistically, complete pharmacologic inhibition of mTOR in immortalized podocytes shifted the cellular energy metabolism toward reduced rates of oxidative phosphorylation and anaerobic glycolysis, which correlated with increased production of reactive oxygen species. Together, these data suggest that podocyte injury and loss is commonly followed by adaptive mTOR activation. Prolonged mTOR activation, however, results in a metabolic podocyte reprogramming leading to increased cellular stress and dedifferentiation, thus offering a treatment rationale for incomplete mTOR inhibition.
Collapse
Affiliation(s)
- Stefan Zschiedrich
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany
| | - Tillmann Bork
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany
| | - Wei Liang
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany.,Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Nicola Wanner
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany
| | - Kristina Eulenbruch
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany
| | - Stefan Munder
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany
| | - Björn Hartleben
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany
| | - Oliver Kretz
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, and
| | - Simon Gerber
- Imagine Institute, Institut national de la santé et de la recherche médicale (INSERM) U1163, Paris Descartes University-Sorbonne Paris Cité, Paris, France
| | - Matias Simons
- Imagine Institute, Institut national de la santé et de la recherche médicale (INSERM) U1163, Paris Descartes University-Sorbonne Paris Cité, Paris, France
| | - Amandine Viau
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany
| | - Martine Burtin
- Institut national de la santé et de la recherche médicale (INSERM) U1151, Université Paris Descartes, Institut Necker Enfants Malades, Hopital Necker, Paris, France
| | - Changli Wei
- Department of Medicine, Rush University Medical Center, Chicago, IL
| | - Jochen Reiser
- Department of Medicine, Rush University Medical Center, Chicago, IL
| | - Nadja Herbach
- Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, Munich, Germany
| | - Maria-Pia Rastaldi
- Renal Research Laboratory, Fondazione Istituto di ricovero e cura a carattere scientifico (IRCCS) Ospedale Maggiore Policlinico and Fondazione D'Amico, Milan, Italy
| | - Clemens D Cohen
- Division of Nephrology, Hypertension and Clinical Immunology, Städtisches Klinikum München, Munich, Germany
| | - Pierre-Louis Tharaux
- Paris Cardiovascular Research Centre (PARCC), Institut National de la Santé et de la Recherche Médicale, Paris, France; and
| | - Fabiola Terzi
- Institut national de la santé et de la recherche médicale (INSERM) U1151, Université Paris Descartes, Institut Necker Enfants Malades, Hopital Necker, Paris, France
| | - Gerd Walz
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany
| | - Markus Gödel
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany
| | - Tobias B Huber
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany; .,BIOSS Centre for Biological Signalling Studies, and.,Center for Systems Biology (ZBSA), Albert-Ludwigs-University Freiburg, Freiburg, Germany.,Department of Medicine III, Faculty of Medicine University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| |
Collapse
|
18
|
Eid S, Boutary S, Braych K, Sabra R, Massaad C, Hamdy A, Rashid A, Moodad S, Block K, Gorin Y, Abboud HE, Eid AA. mTORC2 Signaling Regulates Nox4-Induced Podocyte Depletion in Diabetes. Antioxid Redox Signal 2016; 25:703-719. [PMID: 27393154 PMCID: PMC5079418 DOI: 10.1089/ars.2015.6562] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
AIM Podocyte apoptosis is a critical mechanism for excessive loss of urinary albumin that eventuates in kidney fibrosis. Oxidative stress plays a critical role in hyperglycemia-induced glomerular injury. We explored the hypothesis that mammalian target of rapamycin complex 2 (mTORC2) mediates podocyte injury in diabetes. RESULTS High glucose (HG)-induced podocyte injury reflected by alterations in the slit diaphragm protein podocin and podocyte depletion/apoptosis. This was paralleled by activation of the Rictor/mTORC2/Akt pathway. HG also increased the levels of Nox4 and NADPH oxidase activity. Inhibition of mTORC2 using small interfering RNA (siRNA)-targeting Rictor in vitro decreased HG-induced Nox1 and Nox4, NADPH oxidase activity, restored podocin levels, and reduced podocyte depletion/apoptosis. Inhibition of mTORC2 had no effect on mammalian target of rapamycin complex 1 (mTORC1) activation, described by our group to be increased in diabetes, suggesting that the mTORC2 activation by HG could mediate podocyte injury independently of mTORC1. In isolated glomeruli of OVE26 mice, there was a similar activation of the Rictor/mTORC2/Akt signaling pathway with increase in Nox4 and NADPH oxidase activity. Inhibition of mTORC2 using antisense oligonucleotides targeting Rictor restored podocin levels, reduced podocyte depletion/apoptosis, and attenuated glomerular injury and albuminuria. INNOVATION Our data provide evidence for a novel function of mTORC2 in NADPH oxidase-derived reactive oxygen species generation and podocyte apoptosis that contributes to urinary albumin excretion in type 1 diabetes. CONCLUSION mTORC2 and/or NADPH oxidase inhibition may represent a therapeutic modality for diabetic kidney disease. Antioxid. Redox Signal. 25, 703-719.
Collapse
Affiliation(s)
- Stéphanie Eid
- 1 Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine and Medical Center, American University of Beirut , Beirut, Lebanon .,2 UMR-S 1124 INSERM, Paris Descartes University, Sorbonne Paris Cite University , Centre Interdisciplinaire Chimie Biology, Paris, France
| | - Suzan Boutary
- 1 Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine and Medical Center, American University of Beirut , Beirut, Lebanon
| | - Kawthar Braych
- 1 Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine and Medical Center, American University of Beirut , Beirut, Lebanon
| | - Ramzi Sabra
- 3 Department of Pharmacology and Toxicology, Faculty of Medicine and Medical Center, American University of Beirut , Beirut, Lebanon
| | - Charbel Massaad
- 2 UMR-S 1124 INSERM, Paris Descartes University, Sorbonne Paris Cite University , Centre Interdisciplinaire Chimie Biology, Paris, France
| | - Ahmed Hamdy
- 4 Department of Nephrology, Hamad Medical Corporation , Doha, Qatar
| | - Awad Rashid
- 4 Department of Nephrology, Hamad Medical Corporation , Doha, Qatar
| | - Sarah Moodad
- 1 Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine and Medical Center, American University of Beirut , Beirut, Lebanon
| | - Karen Block
- 5 Department of Medicine, South Texas Veterans Healthcare System and the University of Texas Health Science Center , San Antonio, Texas
| | - Yves Gorin
- 5 Department of Medicine, South Texas Veterans Healthcare System and the University of Texas Health Science Center , San Antonio, Texas
| | - Hanna E Abboud
- 5 Department of Medicine, South Texas Veterans Healthcare System and the University of Texas Health Science Center , San Antonio, Texas
| | - Assaad A Eid
- 1 Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine and Medical Center, American University of Beirut , Beirut, Lebanon
| |
Collapse
|
19
|
Ruggenenti P, Gentile G, Perico N, Perna A, Barcella L, Trillini M, Cortinovis M, Ferrer Siles CP, Reyes Loaeza JA, Aparicio MC, Fasolini G, Gaspari F, Martinetti D, Carrara F, Rubis N, Prandini S, Caroli A, Sharma K, Antiga L, Remuzzi A, Remuzzi G. Effect of Sirolimus on Disease Progression in Patients with Autosomal Dominant Polycystic Kidney Disease and CKD Stages 3b-4. Clin J Am Soc Nephrol 2016; 11:785-794. [PMID: 26912555 PMCID: PMC4858487 DOI: 10.2215/cjn.09900915] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 01/26/2016] [Indexed: 01/13/2023]
Abstract
BACKGROUND AND OBJECTIVES The effect of mammalian target of rapamycin (mTOR) inhibitors has never been tested in patients with autosomal dominant polycystic kidney disease (ADPKD) and severe renal insufficiency. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS In this academic, prospective, randomized, open label, blinded end point, parallel group trial (ClinicalTrials.gov no. NCT01223755), 41 adults with ADPKD, CKD stage 3b or 4, and proteinuria ≤0.5 g/24 h were randomized between September of 2010 and March of 2012 to sirolimus (3 mg/d; serum target levels of 5-10 ng/ml) added on to conventional therapy (n=21) or conventional treatment alone (n=20). Primary outcome was GFR (iohexol plasma clearance) change at 1 and 3 years versus baseline. RESULTS At the 1-year preplanned interim analysis, GFR fell from 26.7±5.8 to 21.3±6.3 ml/min per 1.73 m(2) (P<0.001) and from 29.6±5.6 to 24.9±6.2 ml/min per 1.73 m(2) (P<0.001) in the sirolimus and conventional treatment groups, respectively. Albuminuria (73.8±81.8 versus 154.9±152.9 μg/min; P=0.02) and proteinuria (0.3±0.2 versus 06±0.4 g/24 h; P<0.01) increased with sirolimus. Seven patients on sirolimus versus one control had de novo proteinuria (P=0.04), ten versus three patients doubled proteinuria (P=0.02), 18 versus 11 patients had peripheral edema (P=0.04), and 14 versus six patients had upper respiratory tract infections (P=0.03). Three patients on sirolimus had angioedema, 14 patients had aphthous stomatitis, and seven patients had acne (P<0.01 for both versus controls). Two patients progressed to ESRD, and two patients withdrew because of worsening of proteinuria. These events were not observed in controls. Thus, the independent data and safety monitoring board recommend early trial termination for safety reasons. At 1 year, total kidney volume (assessed by contrast-enhanced computed tomography imaging) increased by 9.0% from 2857.7±1447.3 to 3094.6±1519.5 ml on sirolimus and 4.3% from 3123.4±1695.3 to 3222.6±1651.4 ml on conventional therapy (P=0.12). On follow-up, 37% and 7% of serum sirolimus levels fell below or exceeded the therapeutic range, respectively. CONCLUSIONS Finding that sirolimus was unsafe and ineffective in patients with ADPKD and renal insufficiency suggests that mTOR inhibitor therapy may be contraindicated in this context.
Collapse
Affiliation(s)
- Piero Ruggenenti
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
- Units of Nephrology and Dialysis
| | - Giorgio Gentile
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
- Units of Nephrology and Dialysis
| | - Norberto Perico
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
| | - Annalisa Perna
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
| | | | - Matias Trillini
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
| | - Monica Cortinovis
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
| | - Claudia Patricia Ferrer Siles
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
| | - Jorge Arturo Reyes Loaeza
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
| | - Maria Carolina Aparicio
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
| | - Giorgio Fasolini
- Radiology, Azienda Ospedaliera Papa Giovanni XXIII, Bergamo, Italy; and
| | - Flavio Gaspari
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
| | - Davide Martinetti
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
| | - Fabiola Carrara
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
| | - Nadia Rubis
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
| | - Silvia Prandini
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
| | - Anna Caroli
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
| | - Kanishka Sharma
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
| | - Luca Antiga
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
| | - Andrea Remuzzi
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
| | - Giuseppe Remuzzi
- Clinical Research Center for Rare Diseases “Aldo e Cele Daccò,” IRCCS—Istituto di Ricerche Farmacologiche “Mario Negri,” Bergamo, Italy
- Units of Nephrology and Dialysis
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| |
Collapse
|
20
|
EXP CLIN TRANSPLANTExp Clin Transplant 2015; 13. [DOI: 10.6002/ect.2015.0193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
21
|
Axelsson J, Rippe A, Rippe B. mTOR inhibition with temsirolimus causes acute increases in glomerular permeability, but inhibits the dynamic permeability actions of puromycin aminonucleoside. Am J Physiol Renal Physiol 2015; 308:F1056-64. [PMID: 25740597 DOI: 10.1152/ajprenal.00632.2014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 02/25/2015] [Indexed: 01/21/2023] Open
Abstract
Inhibitors of the mammalian target of rapamycin (mTORi) can produce de novo proteinuria in kidney transplant patients. On the other hand, mTORi has been shown to suppress disease progression in several animal models of kidney disease. In the present study, we investigated whether glomerular permeability can be acutely altered by the mTORi temsirolimus and whether mTORi can affect acute puromycin aminonucleoside (PAN) or angiotensin II (ANG II)-induced glomerular hyperpermeability. In anesthetized Wistar rats, the left ureter was cannulated for urine collection, while simultaneously blood access was achieved. Temsirolimus was administered as a single intravenous dose 30 min before the start of the experiments in animals infused with PAN or ANG II or in nonexposed animals. Polydispersed FITC-Ficoll-70/400 (molecular radius 10-80 Å) and (51)Cr-EDTA infusion was given during the whole experiment. Measurements of Ficoll in plasma and urine were performed sequentially before the temsirolimus injection (baseline) and at 5, 15, 30, 60, and 120 min after the start of the experiments. Urine and plasma samples were analyzed by high-performance size-exclusion chromatography (HPSEC) to assess glomerular sieving coefficients (θ) for Ficoll10-80Å. Temsirolimus per se increased baseline glomerular permeability to Ficoll50-80Å 45 min after its administration, a reactive oxygen species (ROS)-dependent phenomenon. PAN caused a rapid and reversible increase in glomerular permeability, peaking at 5 min, and again at 60-120 min, which could be blocked by the ROS scavenger tempol. mTORi abrogated the second permeability peak induced by PAN. However, it had no effect on the immediate ANG II- or PAN-induced increases in glomerular permeability.
Collapse
Affiliation(s)
| | - Anna Rippe
- Department of Nephrology, Lund University, Lund, Sweden
| | - Bengt Rippe
- Department of Nephrology, Lund University, Lund, Sweden
| |
Collapse
|
22
|
Grahammer F, Wanner N, Huber TB. mTOR controls kidney epithelia in health and disease. Nephrol Dial Transplant 2014; 29 Suppl 1:i9-i18. [PMID: 24493874 DOI: 10.1093/ndt/gft491] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Renal epithelial function is the cornerstone of key excretory processes performed by our kidneys. Most of these tasks need to be tightly controlled to keep our internal environment in balance. Recently, the mTOR signalling network emerged as a key pathway controlling renal epithelial cells from the glomerular tuft along the entire nephron. Both mTOR complexes, mTORC1 and mTORC2, regulate such diverse processes as glomerular filtration and the fine tuning of tubular electrolyte balance. Most importantly, dysregulation of mTOR signalling contributes to prevalent kidney diseases like diabetic nephropathy and cystic kidney disease. The following review shall summarize our current knowledge of the renal epithelial mTOR signalling system under physiological and pathophysiological conditions.
Collapse
Affiliation(s)
- Florian Grahammer
- Renal Division, Department of Medicine, University of Freiburg, Freiburg, Germany
| | | | | |
Collapse
|
23
|
Das F, Bera A, Ghosh-Choudhury N, Abboud HE, Kasinath BS, Choudhury GG. TGFβ-induced deptor suppression recruits mTORC1 and not mTORC2 to enhance collagen I (α2) gene expression. PLoS One 2014; 9:e109608. [PMID: 25333702 PMCID: PMC4198127 DOI: 10.1371/journal.pone.0109608] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 09/02/2014] [Indexed: 02/06/2023] Open
Abstract
Enhanced TGFβ activity contributes to the accumulation of matrix proteins including collagen I (α2) by proximal tubular epithelial cells in progressive kidney disease. Although TGFβ rapidly activates its canonical Smad signaling pathway, it also recruits noncanonical pathway involving mTOR kinase to regulate renal matrix expansion. The mechanism by which chronic TGFβ treatment maintains increased mTOR activity to induce the matrix protein collagen I (α2) expression is not known. Deptor is an mTOR interacting protein that suppresses mTOR activity in both mTORC1 and mTORC2. In proximal tubular epithelial cells, TGFβ reduced deptor levels in a time-dependent manner with concomitant increase in both mTORC1 and mTORC2 activities. Expression of deptor abrogated activity of mTORC1 and mTORC2, resulting in inhibition of collagen I (α2) mRNA and protein expression via transcriptional mechanism. In contrast, neutralization of endogenous deptor by shRNAs increased activity of both mTOR complexes and expression of collagen I (α2) similar to TGFβ treatment. Importantly, downregulation of deptor by TGFβ increased the expression of Hif1α by increasing translation of its mRNA. TGFβ-induced deptor downregulation promotes Hif1α binding to its cognate hypoxia responsive element in the collagen I (α2) gene to control its protein expression via direct transcriptional mechanism. Interestingly, knockdown of raptor to specifically block mTORC1 activity significantly inhibited expression of collagen I (α2) and Hif1α while inhibition of rictor to prevent selectively mTORC2 activation did not have any effect. Critically, our data provide evidence for the requirement of TGFβ-activated mTORC1 only by deptor downregulation, which dominates upon the bystander mTORC2 activity for enhanced expression of collagen I (α2). Our results also suggest the presence of a safeguard mechanism involving deptor-mediated suppression of mTORC1 activity against developing TGFβ-induced renal fibrosis.
Collapse
Affiliation(s)
- Falguni Das
- Departments of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Amit Bera
- Departments of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Nandini Ghosh-Choudhury
- Department of Pathology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- VA Research, South Texas Veterans Health Care System, San Antonio, Texas, United States of America
| | - Hanna E. Abboud
- Departments of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- VA Research, South Texas Veterans Health Care System, San Antonio, Texas, United States of America
| | - Balakuntalam S. Kasinath
- Departments of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- VA Research, South Texas Veterans Health Care System, San Antonio, Texas, United States of America
| | - Goutam Ghosh Choudhury
- Departments of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Geriatric Research, Education and Clinical Center, South Texas Veterans Health Care System, San Antonio, Texas, United States of America
- VA Research, South Texas Veterans Health Care System, San Antonio, Texas, United States of America
- * E-mail:
| |
Collapse
|
24
|
Zeng C, Fan Y, Wu J, Shi S, Chen Z, Zhong Y, Zhang C, Zen K, Liu Z. Podocyte autophagic activity plays a protective role in renal injury and delays the progression of podocytopathies. J Pathol 2014; 234:203-13. [PMID: 24870816 DOI: 10.1002/path.4382] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 05/10/2014] [Accepted: 05/20/2014] [Indexed: 12/22/2022]
Affiliation(s)
- Caihong Zeng
- National Clinical Research Center of Kidney Diseases; Jinling Hospital, Nanjing University School of Medicine; Nanjing Jiangsu 210002 China
| | - Yun Fan
- National Clinical Research Center of Kidney Diseases; Jinling Hospital, Nanjing University School of Medicine; Nanjing Jiangsu 210002 China
| | - Junnan Wu
- National Clinical Research Center of Kidney Diseases; Jinling Hospital, Nanjing University School of Medicine; Nanjing Jiangsu 210002 China
| | - Shaolin Shi
- National Clinical Research Center of Kidney Diseases; Jinling Hospital, Nanjing University School of Medicine; Nanjing Jiangsu 210002 China
| | - Zhaohong Chen
- National Clinical Research Center of Kidney Diseases; Jinling Hospital, Nanjing University School of Medicine; Nanjing Jiangsu 210002 China
| | - Yongzhong Zhong
- National Clinical Research Center of Kidney Diseases; Jinling Hospital, Nanjing University School of Medicine; Nanjing Jiangsu 210002 China
| | - Changming Zhang
- National Clinical Research Center of Kidney Diseases; Jinling Hospital, Nanjing University School of Medicine; Nanjing Jiangsu 210002 China
| | - Ke Zen
- JERC-MBB, State Key Laboratory of Pharmaceutical Biotechnology; Nanjing University School of Life Sciences; Nanjing Jiangsu 210093 China
| | - Zhihong Liu
- National Clinical Research Center of Kidney Diseases; Jinling Hospital, Nanjing University School of Medicine; Nanjing Jiangsu 210002 China
| |
Collapse
|
25
|
Xiao T, Guan X, Nie L, Wang S, Sun L, He T, Huang Y, Zhang J, Yang K, Wang J, Zhao J. Rapamycin promotes podocyte autophagy and ameliorates renal injury in diabetic mice. Mol Cell Biochem 2014; 394:145-54. [DOI: 10.1007/s11010-014-2090-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 05/05/2014] [Indexed: 12/22/2022]
|
26
|
Ohkawa S, Yanagida M, Uchikawa T, Yoshida T, Ikegaya N, Kumagai H. Attenuation of the activated mammalian target of rapamycin pathway might be associated with renal function reserve by a low-protein diet in the rat remnant kidney model. Nutr Res 2013; 33:761-71. [DOI: 10.1016/j.nutres.2013.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 06/10/2013] [Accepted: 06/21/2013] [Indexed: 10/26/2022]
|
27
|
Rapamycin ameliorates proteinuria and restores nephrin and podocin expression in experimental membranous nephropathy. Clin Dev Immunol 2013; 2013:941893. [PMID: 24069045 PMCID: PMC3773418 DOI: 10.1155/2013/941893] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 07/28/2013] [Accepted: 08/01/2013] [Indexed: 12/18/2022]
Abstract
Objective. Recent studies have shown a beneficial effect of rapamycin in passive and active Heymann Nephritis (HN). However, the mechanisms underlying this beneficial effect have not been elucidated. Methods. Passive Heymann Nephritis (PHN) was induced by a single intravenous infusion of anti-Fx1 in 12 Sprague-Dawley male rats. One week later, six of these rats were commenced on daily treatment with subcutaneous rapamycin 0.5 mgr/kg (PHN-Rapa). The remaining six rats were used as the proteinuric control group (PHN) while six more rats without PHN were given the rapamycin solvent and served as the healthy control group (HC). All rats were sacrificed at the end of the 7th week. Results. Rapamycin significantly reduced proteinuria during the autologous phase of PHN. Histological lesions were markedly improved by rapamycin. Immunofluorescence revealed attenuated deposits of autologous alloantibodies in treated rats. Untreated rats showed decreased glomerular content of both nephrin and podocin whereas rapamycin restored their expression. Conclusions. Rapamycin monotherapy significantly improves proteinuria and histological lesions in experimental membranous nephropathy. This beneficial effect may be mediated by inhibition of the alloimmune response during the autologous phase of PHN and by restoration of the normal expression of the podocyte proteins nephrin and podocin.
Collapse
|
28
|
Satriano J, Sharma K. Autophagy and metabolic changes in obesity-related chronic kidney disease. Nephrol Dial Transplant 2013; 28 Suppl 4:iv29-36. [PMID: 23901047 DOI: 10.1093/ndt/gft229] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Obesity is a long-term source of cellular stress that predisposes to chronic kidney disease (CKD). Autophagy is a homeostatic mechanism for cellular quality control through the disposal and recycling of cellular components. During times of cellular stress, autophagy affords mechanisms to manage stress by selectively ridding the cell of the accumulation of potentially toxic proteins, lipids and organelles. The adaptive processes employed may vary between cell types and selectively adjust to the insult by inducing components of the basic autophagy machinery utilized by the cells while not under duress. In this review, we will discuss the autophagic responses of organs to cellular stressors, such as high-fat diet, obesity and diabetes, and how these mechanisms may prevent or promote the progression of disease. The identification of early cellular mechanisms in the advent of obesity- and diabetes-related renal complications could afford avenues for future therapeutic interventions.
Collapse
Affiliation(s)
- Joseph Satriano
- Division of Nephrology-Hypertension and O'Brien Kidney Center, Center for Renal Translational Medicine, Stein Institute for Research on Aging, University of California San Diego and the Veterans Administration San Diego Healthcare System, La Jolla, CA, USA
| | | |
Collapse
|
29
|
Abstract
Ninety-one years ago insulin was discovered, which was one of the most important medical discoveries in the past century, transforming the lives of millions of diabetic patients. Initially insulin was considered only important for rapid control of blood glucose by its action on a restricted number of tissues; however, it has now become clear that this hormone controls an array of cellular processes in many different tissues. The present review will focus on the role of insulin in the kidney in health and disease.
Collapse
|
30
|
Monteverde ML, Ibañez J, Balbarrey Z, Chaparro A, Diaz M, Turconi A. Conversion to sirolimus in pediatric renal transplant patients: a single-center experience. Pediatr Transplant 2012; 16:582-8. [PMID: 22533794 DOI: 10.1111/j.1399-3046.2012.01697.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We studied efficacy and safety of conversion from CNI- to SRL-based immunosuppression in 92 kidney TX recipients, mainly due to CAN (69%). Median time of conversion was 31 months (r: 0.3-165); median time of follow-up: 36 months (r: 2-102). In the whole group mean eGFR increased from 53 ± 22 to 67 ± 26mL/min/1.73 m(2) at three months (p = 0.02) and did not change subsequently. Patients with grade I CAN had higher eGFR than those with grade II CAN. Patient and graft survival was 96% and 70% 10 yr after conversion. Patients with grade I CAN had better graft survival than those with grade II CAN: 89% vs. 65% at six yr (p = 0.02) post conversion. There were two episodes of BPAR. Baseline proteinuria >20 mg/kg/day (HR: 10) and baseline eGFR <50 mL/min/1.73 m(2) (HR: 8) were independent predictors of graft loss. Sixty-seven of 92 subjects had ≥1 AEs: diarrhea (n = 52), urinary tract infections (n = 35), and lower respiratory tract infections (n = 12) were the most frequent. Patients with >2 AEs had SRL blood levels >9 ng/mL at month 3 (p = 0.01). In conclusion, patients converted from CNI to SRL had good graft survival and tolerable but frequent AEs. Independent predictors of graft loss were baseline proteinuria and eGFR.
Collapse
|
31
|
Understanding the mechanisms of proteinuria: therapeutic implications. Int J Nephrol 2012; 2012:546039. [PMID: 22844592 PMCID: PMC3398673 DOI: 10.1155/2012/546039] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 04/30/2012] [Indexed: 12/18/2022] Open
Abstract
A large body of evidence indicates that proteinuria is a strong predictor of morbidity, a cause of inflammation, oxidative stress and progression of chronic kidney disease, and development of cardiovascular disease. The processes that lead to proteinuria are complex and involve factors such as glomerular hemodynamic, tubular absorption, and diffusion gradients. Alterations in various different molecular pathways and interactions may lead to the identical clinical end points of proteinuria and chronic kidney disease. Glomerular diseases include a wide range of immune and nonimmune insults that may target and thus damage some components of the glomerular filtration barrier. In many of these conditions, the renal visceral epithelial cell (podocyte) responds to injury along defined pathways, which may explain the resultant clinical and histological changes. The recent discovery of the molecular components of the slit diaphragm, specialized structure of podocyte-podocyte interaction, has been a major breakthrough in understanding the crucial role of the epithelial layer of the glomerular barrier and the pathogenesis of proteinuria. This paper provides an overview and update on the structure and function of the glomerular filtration barrier and the pathogenesis of proteinuria, highlighting the role of the podocyte in this setting. In addition, current antiproteinuric therapeutic approaches are briefly commented.
Collapse
|
32
|
|
33
|
Yan K, Ito N, Nakajo A, Kurayama R, Fukuhara D, Nishibori Y, Kudo A, Akimoto Y, Takenaka H. The struggle for energy in podocytes leads to nephrotic syndrome. Cell Cycle 2012; 11:1504-11. [PMID: 22433955 DOI: 10.4161/cc.19825] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Podocytes are terminally differentiated post-mitotic cells similar to neurons, and their damage leads to nephrotic syndrome, which is characterized by massive proteinuria associated with generalized edema. A recent functional genetic approach has identified the pathological relevance of several mutated proteins in glomerular podocytes to the mechanism of proteinuria in hereditary nephrotic syndrome. In contrast, the pathophysiology of acquired primary nephrotic syndrome, including minimal change disease, is still largely unknown. We recently demonstrated the possible linkage of an energy-consuming process in glomerular podocytes to the mechanism of proteinuria. Puromycin aminonucleoside nephrosis, a rat model of minimal change disease, revealed the activation of the unfolded protein response (UPR) in glomerular podocytes to be a cause of proteinuria. The pretreatment of puromycin aminonucleoside rat podocytes and cultured podocytes with the mammalian target of rapamycin (mTOR) inhibitor everolimus further revealed that mTOR complex 1 consumed energy, which was followed by UPR activation. In this paper, we will review nutritional transporters to summarize the energy uptake process in podocytes and review the involvement of the UPR in the pathogenesis of glomerular diseases. We will also present additional data that reveal how mTOR complex 1 acts upstream of the UPR. Finally, we will discuss the potential significance of targeting the energy metabolism of podocytes to develop new therapeutic interventions for acquired nephrotic syndrome.
Collapse
Affiliation(s)
- Kunimasa Yan
- Department of Pediatrics, Kyorin University School of Medicine, Mitaka, Tokyo, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Kurdián M, Herrero-Fresneda I, Lloberas N, Gimenez-Bonafe P, Coria V, Grande MT, Boggia J, Malacrida L, Torras J, Arévalo MA, González-Martínez F, López-Novoa JM, Grinyó J, Noboa O. Delayed mTOR inhibition with low dose of everolimus reduces TGFβ expression, attenuates proteinuria and renal damage in the renal mass reduction model. PLoS One 2012; 7:e32516. [PMID: 22427849 PMCID: PMC3299670 DOI: 10.1371/journal.pone.0032516] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 02/01/2012] [Indexed: 12/12/2022] Open
Abstract
Background The immunosuppressive mammalian target of rapamycin (mTOR) inhibitors are widely used in solid organ transplantation, but their effect on kidney disease progression is controversial. mTOR has emerged as one of the main pathways regulating cell growth, proliferation, differentiation, migration, and survival. The aim of this study was to analyze the effects of delayed inhibition of mTOR pathway with low dose of everolimus on progression of renal disease and TGFβ expression in the 5/6 nephrectomy model in Wistar rats. Methods This study evaluated the effects of everolimus (0.3 mg/k/day) introduced 15 days after surgical procedure on renal function, proteinuria, renal histology and mechanisms of fibrosis and proliferation. Results Everolimus treated group (EveG) showed significantly less proteinuria and albuminuria, less glomerular and tubulointerstitial damage and fibrosis, fibroblast activation cell proliferation, when compared with control group (CG), even though the EveG remained with high blood pressure. Treatment with everolimus also diminished glomerular hypertrophy. Everolimus effectively inhibited the increase of mTOR developed in 5/6 nephrectomy animals, without changes in AKT mRNA or protein abundance, but with an increase in the pAKT/AKT ratio. Associated with this inhibition, everolimus blunted the increased expression of TGFβ observed in the remnant kidney model. Conclusion Delayed mTOR inhibition with low dose of everolimus significantly prevented progressive renal damage and protected the remnant kidney. mTOR and TGFβ mRNA reduction can partially explain this anti fibrotic effect. mTOR can be a new target to attenuate the progression of chronic kidney disease even in those nephropathies of non-immunologic origin.
Collapse
Affiliation(s)
- Melania Kurdián
- Centro de Nefrología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
- Departamento de Fisiopatología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Inmaculada Herrero-Fresneda
- Laboratorio de Nefrología Experimental, Departamento de Medicina, Hospital Universitari de Bellvitge, Barcelona, Spain
| | - Nuria Lloberas
- Laboratorio de Nefrología Experimental, Departamento de Medicina, Hospital Universitari de Bellvitge, Barcelona, Spain
| | - Pepita Gimenez-Bonafe
- Departamento de Ciencias Fisiológicas II, Facultad de Medicina, Campus de Bellvitge, Universitat de Barcelona, Spain
| | - Virginia Coria
- Centro de Nefrología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - María T. Grande
- Departamento de Anatomía e Histología Humanas, Facultad de Medicina, Universidad de Salamanca, Salamanca, Spain
| | - José Boggia
- Centro de Nefrología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
- Departamento de Fisiopatología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Leonel Malacrida
- Departamento de Fisiopatología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Joan Torras
- Laboratorio de Nefrología Experimental, Departamento de Medicina, Hospital Universitari de Bellvitge, Barcelona, Spain
| | - Miguel A. Arévalo
- Departamento de Anatomía e Histología Humanas, Facultad de Medicina, Universidad de Salamanca, Salamanca, Spain
| | - Francisco González-Martínez
- Centro de Nefrología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - José M. López-Novoa
- Departamento de Fisiología y Farmacología, Instituto Reina Sofía de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain
| | - Josep Grinyó
- Laboratorio de Nefrología Experimental, Departamento de Medicina, Hospital Universitari de Bellvitge, Barcelona, Spain
| | - Oscar Noboa
- Centro de Nefrología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
- Departamento de Fisiopatología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
- * E-mail:
| |
Collapse
|
35
|
Affiliation(s)
- Shinji Kume
- Department of Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan
| | | | - Daisuke Koya
- Division of Diabetes and Endocrinology, Kanazawa Medical University, Kahoku-Gun, Ishikawa, Japan
- Corresponding author: Daisuke Koya,
| |
Collapse
|
36
|
|
37
|
mTORC1 activation triggers the unfolded protein response in podocytes and leads to nephrotic syndrome. J Transl Med 2011; 91:1584-95. [PMID: 21876538 DOI: 10.1038/labinvest.2011.135] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Although podocyte damage is known to be responsible for the development of minimal-change disease (MCD), the underlying mechanism remains to be elucidated. Previously, using a rat MCD model, we showed that endoplasmic reticulum (ER) stress in the podocytes was associated with the heavy proteinuric state and another group reported that a mammalian target of rapamycin complex 1 (mTORC1) inhibitor protected against proteinuria. In this study, which utilized a rat MCD model, a combination of immunohistochemistry, dual immunofluorescence and confocal microscopy, western blot analysis, and quantitative real-time RT-PCR revealed co-activation of the unfolded protein response (UPR), which was induced by ER stress, and mTORC1 in glomerular podocytes before the onset of proteinuria and downregulation of nephrin at the post-translational level at the onset of proteinuria. Podocyte culture experiments revealed that mTORC1 activation preceded the UPR that was associated with a marked decrease in the energy charge. The mTORC1 inhibitor everolimus completely inhibited proteinuria through a reduction in both mTORC1 and UPR activity and preserved nephrin expression in the glomerular podocytes. In conclusion, mTORC1 activation may perturb the regulatory system of energy metabolism primarily by promoting energy consumption and inducing the UPR, which underlie proteinuria in MCD.
Collapse
|
38
|
Vassiliadis J, Bracken C, Matthews D, O'Brien S, Schiavi S, Wawersik S. Calcium mediates glomerular filtration through calcineurin and mTORC2/Akt signaling. J Am Soc Nephrol 2011; 22:1453-61. [PMID: 21784900 DOI: 10.1681/asn.2010080878] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Alterations to the structure of the glomerular filtration barrier lead to effacement of podocyte foot processes, leakage of albumin, and the development of proteinuria. To better understand the signaling pathways involved in the response of the glomerular filtration barrier to injury, we studied freshly isolated rat glomeruli, which allows for the monitoring and pharmacologic manipulation of early signaling events. Administration of protamine sulfate rapidly damaged the isolated glomeruli, resulting in foot process effacement and albumin leakage. Inhibition of calcium channels and chelation of extracellular calcium reduced protamine sulfate-induced damage, suggesting that calcium signaling plays a critical role in the initial stages of glomerular injury. Calcineurin inhibitors (FK506 and cyclosporine A) and the cathepsin L inhibitor E64 all inhibited protamine sulfate-mediated barrier changes, which suggests that calcium signaling acts, in part, through calcineurin- and cathepsin L-dependent cleavage of synaptopodin, a regulator of actin dynamics. The mTOR inhibitor rapamycin also protected glomeruli, demonstrating that calcium signaling has additional calcineurin-independent components. Furthermore, activation of Akt through mTOR had a direct role on glomerular barrier integrity, and activation of calcium channels mediated this process, likely independent of phosphoinositide 3-kinase. Taken together, these results demonstrate the importance of calcium and related signaling pathways in the structure and function of the glomerular filtration barrier.
Collapse
Affiliation(s)
- John Vassiliadis
- Endocrine and Renal Science, Genzyme Corporation, Framingham, MA 01701, USA.
| | | | | | | | | | | |
Collapse
|
39
|
Sirolimus and proteinuria in renal transplant patients: evidence for a dose-dependent effect on slit diaphragm-associated proteins. Transplantation 2011; 91:997-1004. [PMID: 21364499 DOI: 10.1097/tp.0b013e318211d342] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The mechanisms underlying the development of proteinuria in renal-transplant recipients converted from calcineurin inhibitors to sirolimus are still unknown. METHODS This is a single-center cohort study. One hundred ten kidney transplant recipients converted from calcineurin inhibitors to sirolimus in the period from September 2000 to December 2005 were included in the study. All patients underwent a graft biopsy before conversion (T0) and a second protocol biopsy 2 years thereafter (T2), according to our standard clinical protocol. On the basis of the changes observed in proteinuria between T0 and T2 (median 70%), the patients were divided into two groups: group I (<70%) and group II (>70%). The authors blinded the sirolimus blood trough levels. We investigated in vivo the effects of sirolimus on nephrin, podocin, CD2ap, and actin protein expression. Slit diaphragm (SD)-associated protein expressions were evaluated in T0 and T2 biopsies. The same analysis was performed in cultured human podocytes treated with different doses of sirolimus (5, 10, 20, and 50 ng/mL). RESULTS The SD protein expression in group II T2 biopsies was significantly reduced compared with the T0 biopsies and with T2 group I biopsies. In addition, sirolimus blood trough levels directly and significantly correlated with the SD protein expression at T2 graft biopsies. Group II patients presented significantly higher sirolimus blood levels than group I. In vitro study confirmed that sirolimus effect on podocytes was dose dependent. CONCLUSIONS Our data suggest that sirolimus-induced proteinuria may be a dose-dependent effect of the drug on key podocyte structures.
Collapse
|
40
|
Gödel M, Hartleben B, Herbach N, Liu S, Zschiedrich S, Lu S, Debreczeni-Mór A, Lindenmeyer MT, Rastaldi MP, Hartleben G, Wiech T, Fornoni A, Nelson RG, Kretzler M, Wanke R, Pavenstädt H, Kerjaschki D, Cohen CD, Hall MN, Rüegg MA, Inoki K, Walz G, Huber TB. Role of mTOR in podocyte function and diabetic nephropathy in humans and mice. J Clin Invest 2011; 121:2197-209. [PMID: 21606591 PMCID: PMC3104746 DOI: 10.1172/jci44774] [Citation(s) in RCA: 434] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 03/08/2011] [Indexed: 02/06/2023] Open
Abstract
Chronic glomerular diseases, associated with renal failure and cardiovascular morbidity, represent a major health issue. However, they remain poorly understood. Here we have reported that tightly controlled mTOR activity was crucial to maintaining glomerular podocyte function, while dysregulation of mTOR facilitated glomerular diseases. Genetic deletion of mTOR complex 1 (mTORC1) in mouse podocytes induced proteinuria and progressive glomerulosclerosis. Furthermore, simultaneous deletion of both mTORC1 and mTORC2 from mouse podocytes aggravated the glomerular lesions, revealing the importance of both mTOR complexes for podocyte homeostasis. In contrast, increased mTOR activity accompanied human diabetic nephropathy, characterized by early glomerular hypertrophy and hyperfiltration. Curtailing mTORC1 signaling in mice by genetically reducing mTORC1 copy number in podocytes prevented glomerulosclerosis and significantly ameliorated the progression of glomerular disease in diabetic nephropathy. These results demonstrate the requirement for tightly balanced mTOR activity in podocyte homeostasis and suggest that mTOR inhibition can protect podocytes and prevent progressive diabetic nephropathy.
Collapse
Affiliation(s)
- Markus Gödel
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Björn Hartleben
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Nadja Herbach
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Shuya Liu
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Stefan Zschiedrich
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Shun Lu
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Andrea Debreczeni-Mór
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Maja T. Lindenmeyer
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Maria-Pia Rastaldi
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Götz Hartleben
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Thorsten Wiech
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Alessia Fornoni
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Robert G. Nelson
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Matthias Kretzler
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Rüdiger Wanke
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Hermann Pavenstädt
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Dontscho Kerjaschki
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Clemens D. Cohen
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Michael N. Hall
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Markus A. Rüegg
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Ken Inoki
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Gerd Walz
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Tobias B. Huber
- Renal Division, University Hospital Freiburg, Freiburg, Germany.
Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, München, Germany.
Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany.
Division of Nephrology and Institute of Physiology, University Hospital and University of Zürich, Zürich, Switzerland.
Renal Research Laboratory, Fondazione IRCCS Ospedale Maggiore Policlinico and Fondazione D’Amico, Milan, Italy.
Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.
Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
Diabetes Research Institute, L. Miller School of Medicine, University of Miami, Miami, Florida, USA.
National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona, USA.
Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA.
Department of Medicine D, University Hospital Münster, Münster, Germany.
Department of Pathology, Medical University of Vienna, Wien, Austria.
Biozentrum, University of Basel, Basel, Switzerland.
Life Sciences Institute, Department of Molecular and Integrative Physiology, and Division of Nephology, Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, Freiburg, Germany
| |
Collapse
|
41
|
Inoki K, Mori H, Wang J, Suzuki T, Hong S, Yoshida S, Blattner SM, Ikenoue T, Rüegg MA, Hall MN, Kwiatkowski DJ, Rastaldi MP, Huber TB, Kretzler M, Holzman LB, Wiggins RC, Guan KL. mTORC1 activation in podocytes is a critical step in the development of diabetic nephropathy in mice. J Clin Invest 2011; 121:2181-96. [PMID: 21606597 PMCID: PMC3104745 DOI: 10.1172/jci44771] [Citation(s) in RCA: 429] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2010] [Accepted: 03/08/2011] [Indexed: 02/06/2023] Open
Abstract
Diabetic nephropathy (DN) is among the most lethal complications that occur in type 1 and type 2 diabetics. Podocyte dysfunction is postulated to be a critical event associated with proteinuria and glomerulosclerosis in glomerular diseases including DN. However, molecular mechanisms of podocyte dysfunction in the development of DN are not well understood. Here we have shown that activity of mTOR complex 1 (mTORC1), a kinase that senses nutrient availability, was enhanced in the podocytes of diabetic animals. Further, podocyte-specific mTORC1 activation induced by ablation of an upstream negative regulator (PcKOTsc1) recapitulated many DN features, including podocyte loss, glomerular basement membrane thickening, mesangial expansion, and proteinuria in nondiabetic young and adult mice. Abnormal mTORC1 activation caused mislocalization of slit diaphragm proteins and induced an epithelial-mesenchymal transition-like phenotypic switch with enhanced ER stress in podocytes. Conversely, reduction of ER stress with a chemical chaperone significantly protected against both the podocyte phenotypic switch and podocyte loss in PcKOTsc1 mice. Finally, genetic reduction of podocyte-specific mTORC1 in diabetic animals suppressed the development of DN. These results indicate that mTORC1 activation in podocytes is a critical event in inducing DN and suggest that reduction of podocyte mTORC1 activity is a potential therapeutic strategy to prevent DN.
Collapse
Affiliation(s)
- Ken Inoki
- Life Sciences Institute,
Department of Molecular and Integrative Physiology, and
Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Biozentrum, University of Basel, Basel, Switzerland.
Translational Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Renal Research Laboratory, Fondazione IRCCS Policlinico and Fondazione D’Amico, Milan, Italy.
Renal Division, University Hospital Freiburg, Freiburg, Germany.
Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University, Freiburg, Germany.
Renal Electrolyte and Hypertension Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pharmacology, Moores Cancer Center, UCSD, San Diego, California, USA
| | - Hiroyuki Mori
- Life Sciences Institute,
Department of Molecular and Integrative Physiology, and
Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Biozentrum, University of Basel, Basel, Switzerland.
Translational Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Renal Research Laboratory, Fondazione IRCCS Policlinico and Fondazione D’Amico, Milan, Italy.
Renal Division, University Hospital Freiburg, Freiburg, Germany.
Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University, Freiburg, Germany.
Renal Electrolyte and Hypertension Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pharmacology, Moores Cancer Center, UCSD, San Diego, California, USA
| | - Junying Wang
- Life Sciences Institute,
Department of Molecular and Integrative Physiology, and
Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Biozentrum, University of Basel, Basel, Switzerland.
Translational Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Renal Research Laboratory, Fondazione IRCCS Policlinico and Fondazione D’Amico, Milan, Italy.
Renal Division, University Hospital Freiburg, Freiburg, Germany.
Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University, Freiburg, Germany.
Renal Electrolyte and Hypertension Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pharmacology, Moores Cancer Center, UCSD, San Diego, California, USA
| | - Tsukasa Suzuki
- Life Sciences Institute,
Department of Molecular and Integrative Physiology, and
Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Biozentrum, University of Basel, Basel, Switzerland.
Translational Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Renal Research Laboratory, Fondazione IRCCS Policlinico and Fondazione D’Amico, Milan, Italy.
Renal Division, University Hospital Freiburg, Freiburg, Germany.
Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University, Freiburg, Germany.
Renal Electrolyte and Hypertension Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pharmacology, Moores Cancer Center, UCSD, San Diego, California, USA
| | - SungKi Hong
- Life Sciences Institute,
Department of Molecular and Integrative Physiology, and
Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Biozentrum, University of Basel, Basel, Switzerland.
Translational Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Renal Research Laboratory, Fondazione IRCCS Policlinico and Fondazione D’Amico, Milan, Italy.
Renal Division, University Hospital Freiburg, Freiburg, Germany.
Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University, Freiburg, Germany.
Renal Electrolyte and Hypertension Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pharmacology, Moores Cancer Center, UCSD, San Diego, California, USA
| | - Sei Yoshida
- Life Sciences Institute,
Department of Molecular and Integrative Physiology, and
Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Biozentrum, University of Basel, Basel, Switzerland.
Translational Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Renal Research Laboratory, Fondazione IRCCS Policlinico and Fondazione D’Amico, Milan, Italy.
Renal Division, University Hospital Freiburg, Freiburg, Germany.
Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University, Freiburg, Germany.
Renal Electrolyte and Hypertension Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pharmacology, Moores Cancer Center, UCSD, San Diego, California, USA
| | - Simone M. Blattner
- Life Sciences Institute,
Department of Molecular and Integrative Physiology, and
Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Biozentrum, University of Basel, Basel, Switzerland.
Translational Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Renal Research Laboratory, Fondazione IRCCS Policlinico and Fondazione D’Amico, Milan, Italy.
Renal Division, University Hospital Freiburg, Freiburg, Germany.
Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University, Freiburg, Germany.
Renal Electrolyte and Hypertension Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pharmacology, Moores Cancer Center, UCSD, San Diego, California, USA
| | - Tsuneo Ikenoue
- Life Sciences Institute,
Department of Molecular and Integrative Physiology, and
Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Biozentrum, University of Basel, Basel, Switzerland.
Translational Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Renal Research Laboratory, Fondazione IRCCS Policlinico and Fondazione D’Amico, Milan, Italy.
Renal Division, University Hospital Freiburg, Freiburg, Germany.
Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University, Freiburg, Germany.
Renal Electrolyte and Hypertension Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pharmacology, Moores Cancer Center, UCSD, San Diego, California, USA
| | - Markus A. Rüegg
- Life Sciences Institute,
Department of Molecular and Integrative Physiology, and
Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Biozentrum, University of Basel, Basel, Switzerland.
Translational Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Renal Research Laboratory, Fondazione IRCCS Policlinico and Fondazione D’Amico, Milan, Italy.
Renal Division, University Hospital Freiburg, Freiburg, Germany.
Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University, Freiburg, Germany.
Renal Electrolyte and Hypertension Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pharmacology, Moores Cancer Center, UCSD, San Diego, California, USA
| | - Michael N. Hall
- Life Sciences Institute,
Department of Molecular and Integrative Physiology, and
Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Biozentrum, University of Basel, Basel, Switzerland.
Translational Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Renal Research Laboratory, Fondazione IRCCS Policlinico and Fondazione D’Amico, Milan, Italy.
Renal Division, University Hospital Freiburg, Freiburg, Germany.
Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University, Freiburg, Germany.
Renal Electrolyte and Hypertension Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pharmacology, Moores Cancer Center, UCSD, San Diego, California, USA
| | - David J. Kwiatkowski
- Life Sciences Institute,
Department of Molecular and Integrative Physiology, and
Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Biozentrum, University of Basel, Basel, Switzerland.
Translational Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Renal Research Laboratory, Fondazione IRCCS Policlinico and Fondazione D’Amico, Milan, Italy.
Renal Division, University Hospital Freiburg, Freiburg, Germany.
Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University, Freiburg, Germany.
Renal Electrolyte and Hypertension Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pharmacology, Moores Cancer Center, UCSD, San Diego, California, USA
| | - Maria P. Rastaldi
- Life Sciences Institute,
Department of Molecular and Integrative Physiology, and
Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Biozentrum, University of Basel, Basel, Switzerland.
Translational Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Renal Research Laboratory, Fondazione IRCCS Policlinico and Fondazione D’Amico, Milan, Italy.
Renal Division, University Hospital Freiburg, Freiburg, Germany.
Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University, Freiburg, Germany.
Renal Electrolyte and Hypertension Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pharmacology, Moores Cancer Center, UCSD, San Diego, California, USA
| | - Tobias B. Huber
- Life Sciences Institute,
Department of Molecular and Integrative Physiology, and
Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Biozentrum, University of Basel, Basel, Switzerland.
Translational Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Renal Research Laboratory, Fondazione IRCCS Policlinico and Fondazione D’Amico, Milan, Italy.
Renal Division, University Hospital Freiburg, Freiburg, Germany.
Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University, Freiburg, Germany.
Renal Electrolyte and Hypertension Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pharmacology, Moores Cancer Center, UCSD, San Diego, California, USA
| | - Matthias Kretzler
- Life Sciences Institute,
Department of Molecular and Integrative Physiology, and
Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Biozentrum, University of Basel, Basel, Switzerland.
Translational Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Renal Research Laboratory, Fondazione IRCCS Policlinico and Fondazione D’Amico, Milan, Italy.
Renal Division, University Hospital Freiburg, Freiburg, Germany.
Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University, Freiburg, Germany.
Renal Electrolyte and Hypertension Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pharmacology, Moores Cancer Center, UCSD, San Diego, California, USA
| | - Lawrence B. Holzman
- Life Sciences Institute,
Department of Molecular and Integrative Physiology, and
Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Biozentrum, University of Basel, Basel, Switzerland.
Translational Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Renal Research Laboratory, Fondazione IRCCS Policlinico and Fondazione D’Amico, Milan, Italy.
Renal Division, University Hospital Freiburg, Freiburg, Germany.
Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University, Freiburg, Germany.
Renal Electrolyte and Hypertension Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pharmacology, Moores Cancer Center, UCSD, San Diego, California, USA
| | - Roger C. Wiggins
- Life Sciences Institute,
Department of Molecular and Integrative Physiology, and
Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Biozentrum, University of Basel, Basel, Switzerland.
Translational Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Renal Research Laboratory, Fondazione IRCCS Policlinico and Fondazione D’Amico, Milan, Italy.
Renal Division, University Hospital Freiburg, Freiburg, Germany.
Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University, Freiburg, Germany.
Renal Electrolyte and Hypertension Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pharmacology, Moores Cancer Center, UCSD, San Diego, California, USA
| | - Kun-Liang Guan
- Life Sciences Institute,
Department of Molecular and Integrative Physiology, and
Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Biozentrum, University of Basel, Basel, Switzerland.
Translational Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Renal Research Laboratory, Fondazione IRCCS Policlinico and Fondazione D’Amico, Milan, Italy.
Renal Division, University Hospital Freiburg, Freiburg, Germany.
Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University, Freiburg, Germany.
Renal Electrolyte and Hypertension Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pharmacology, Moores Cancer Center, UCSD, San Diego, California, USA
| |
Collapse
|
42
|
Cruzado JM, Poveda R, Ibernón M, Díaz M, Fulladosa X, Carrera M, Torras J, Bestard O, Navarro I, Ballarín J, Romero R, Grinyó JM. Low-dose sirolimus combined with angiotensin-converting enzyme inhibitor and statin stabilizes renal function and reduces glomerular proliferation in poor prognosis IgA nephropathy. Nephrol Dial Transplant 2011; 26:3596-602. [PMID: 21393611 DOI: 10.1093/ndt/gfr072] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND There is a lack of new therapeutic strategies for IgA nephropathy. Low-dose sirolimus inhibits mesangial cell proliferation and renal fibrosis in animal models. METHODS We performed a pilot, randomized controlled trial to evaluate the efficacy and safety of low-dose sirolimus in patients with a high-risk IgA nephropathy. Twenty-three patients with a glomerular filtration rate (GFR) within 30-60 mL/min and/or proteinuria >1 g/day were randomly assigned to low-dose sirolimus plus enalapril and atorvastatin (SRL group, n = 14) or enalapril plus atorvastatin (CONTROL group, n = 9). Primary composite end point was variation of haematuria, proteinuria and blood pressure. Secondary end points were isotopic GFR, renal histology evaluated by Oxford classification and safety parameters evaluated at 6 and 12 months. RESULTS Primary end point improved significantly in the SRL group at 12 months. Regarding isotopic GFR, patients included in the CONTROL group lost 8 mL/min/1.73 m(2), whereas those in the SRL arm improved 5 mL/min/1.73 m(2) (P = 0.03). Proteinuria decreased similarly in both study groups. At 1 year, SRL treatment was associated with a significant reduction of mesangial and endocapillary proliferation, whereas glomerular sclerosis, tubular atrophy and interstitial fibrosis were similar. Sirolimus was well tolerated; all patients remained on therapy at 12 months. CONCLUSION The addition of low-dose sirolimus to enalapril and statin is safe, stabilizes renal function and reduces glomerular proliferative lesions in patients with poor prognosis IgA nephropathy.
Collapse
Affiliation(s)
- Josep M Cruzado
- Department of Nephrology, Hospital Universitari de Bellvitge, University of Barcelona, IDIBELL, L’Hospitalet de Llobregat, Barcelona, Spain.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
mTOR and rapamycin in the kidney: signaling and therapeutic implications beyond immunosuppression. Kidney Int 2011; 79:502-11. [DOI: 10.1038/ki.2010.457] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
44
|
Zhao Y, Tao Z, Xu Z, Tao Z, Chen B, Wang L, Li C, Chen L, Jia Q, Jia E, Zhu T, Yang Z. Toxic effects of a high dose of non-ionic iodinated contrast media on renal glomerular and aortic endothelial cells in aged rats in vivo. Toxicol Lett 2011; 202:253-60. [PMID: 21354280 DOI: 10.1016/j.toxlet.2011.02.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2010] [Revised: 02/16/2011] [Accepted: 02/17/2011] [Indexed: 10/18/2022]
Abstract
Iodinated contrast media (CM) can induce apoptosis and necrosis of renal tubular cells. The injuries of endothelial cells induced by CM on the systemic condition have not been fully understood. To assess the toxic effects of non-ionic CM on the glomerular and aortic endothelial cells, iopromide and iodixanol, two kinds of representative non-ionic CM, were used for the in vivo study. Sixty aged rats were respectively received the agents or normal sodium intravascularly. No obvious apoptosis and morphological change was detected in the glomerular and aortic endothelial cells apart from renal tubules after CM administration. However, expressions of the nitric oxide synthase (eNOS) in glomerular endothelium were decreased at 12h after CM injection. Furthermore, plasma creatinine and endothelin-1 were increased and plasma nitric oxide (NO) was decreased significantly after CM administration. However, we failed to observe the significant increase of plasma von Willebrand Factor. These results suggest that non-ionic iodinated CM do not induce apoptosis and necrosis of glomerular and aortic endothelial cells in vivo. Decreased eNOS expression and increased plasma endothelin-1 may be involved in non-ionic iodinated CM-induced endothelial dysfunction and kidney injury.
Collapse
Affiliation(s)
- Yingming Zhao
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Guangzhou Road 300, Nanjing 210029, China
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Cravedi P, Ruggenenti P, Remuzzi G. Sirolimus for calcineurin inhibitors in organ transplantation: contra. Kidney Int 2010; 78:1068-74. [DOI: 10.1038/ki.2010.268] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
|
46
|
Liu G, Han F, Yang Y, Xie Y, Jiang H, Mao Y, Wang H, Wang M, Chen R, Yang J, Chen J. Evaluation of sphingolipid metabolism in renal cortex of rats with streptozotocin-induced diabetes and the effects of rapamycin. Nephrol Dial Transplant 2010; 26:1493-502. [PMID: 20961887 DOI: 10.1093/ndt/gfq633] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Abnormal lipid metabolism contributes to the pathogenesis of diabetes, but it is uncertain whether it plays a role in the development of diabetic nephropathy (DN). While rapamycin was shown to prevent DN development in streptozotocin (STZ)-induced diabetic rats in our previous studies, it is unknown if it intervenes with lipid metabolism. METHODS We divided the rats into four groups: normal control rats, rapamycin-treated normal rats, diabetic rats and rapamycin-treated DN rats. The apoptosis was evaluated by immunohistochemistry. The crude lipid and sphingolipid were extracted from rat renal cortex and analysed by matrix-assisted laser desorption ionization-time of flight mass spectrometry. The expression of the three key enzymes in sphingolipid metabolism including serine palmitoyltransferase, acid sphingomyelinase and sphingomyelin synthase was measured by western blot and immunohistochemistry in rat renal cortex. RESULTS The level of apoptosis was increased in diabetic rats, and rapamycin treatment reduced apoptosis. STZ treatment significantly increased formation of many sphingolipids species through elevated de novo synthesis. These changes were inhibited by treatment with rapamycin. CONCLUSIONS Accumulation of sphingolipids contributes to STZ-induced diabetes, and the therapeutic effect of rapamycin on diabetic nephropathy is partly through suppression of sphingolipid abnormality.
Collapse
Affiliation(s)
- GuangYi Liu
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Schönenberger E, Ehrich JH, Haller H, Schiffer M. The podocyte as a direct target of immunosuppressive agents. Nephrol Dial Transplant 2010; 26:18-24. [PMID: 20937691 DOI: 10.1093/ndt/gfq617] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Podocytes play a key role in maintaining the blood-urine barrier for high-molecular-weight proteins. They are considered to be terminally differentiated, and podocyte loss cannot be compensated by regenerative proliferation. Various diseases leading to podocyte damage and loss result in proteinuria and cause nephrotic syndrome. Therefore, direct therapeutical strategies to protect podocytes in disease situations are a logical concept to prevent disease or to delay disease progression. Acquired podocytopathies like idiopathic focal segmental glomerulosclerosis and minimal change disease are historically considered as immunological diseases. Therefore, immunosuppressive agents such as steroids and calcineurin inhibitors are the commonly used treatment strategies. However, the causative disease mechanisms behind these treatment strategies remain elusive. Recent evidence shows that immunosuppressive agents, in addition to the effect on the immune system, directly influence the unique structure and function of podocytes. In this context, the actin cytoskeleton of the podocyte and cytokines such as vascular endothelial growth factor play a pivotal role. In this review, we summarize the direct effects on podocytes obtained in vivo and in vitro after treatment with calcineurin inhibitors, mTOR inhibitors and glucocorticoids. These direct effects could play a key role in the treatment concepts of podocytopathies with an important impact on the long-term renal function in patients with pharmacological immunosuppression.
Collapse
|
48
|
Biancone L, Bussolati B, Mazzucco G, Barreca A, Gallo E, Rossetti M, Messina M, Nuschak B, Fop F, Medica D, Cantaluppi V, Camussi G, Segoloni GP. Loss of nephrin expression in glomeruli of kidney-transplanted patients under m-TOR inhibitor therapy. Am J Transplant 2010; 10:2270-8. [PMID: 20840477 DOI: 10.1111/j.1600-6143.2010.03259.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The development of proteinuria has been observed in kidney-transplanted patients on m-TOR inhibitor (m-TORi) treatment. Recent studies suggest that m-TORi(s) may alter the behavior and integrity of glomerular podocytes. We analyzed renal biopsies from kidney-transplanted patients and evaluated the expression of nephrin, a critical component of the glomerular slit-diaphragm. In a group of patients on 'de novo' m-TORi-treatment, the expression of nephrin within glomeruli was significantly reduced in all cases compared to pretransplant donor biopsies. Biopsies from control transplant patients not treated with m-TORi(s) failed to present a loss of nephrin. In a group of patients subsequently converted to m-TORi-treatment, a protocol biopsy performed before introduction of m-TORi was also available. The expression of nephrin in the pre-m-TORi biopsies was similar to that observed in the pretransplant donor biopsies but was significantly reduced after introduction of m-TORi(s). Proteinuria increased after the m-TORi inititiation in this group. However, in some cases proteinuria remained normal despite reduction of nephrin. In vitro, sirolimus downregulated nephrin expression by human podocytes. Our results suggest that m-TORi(s) may affect nephrin expression in kidney-transplanted patients, consistently with the observation in vitro on cultured podocytes.
Collapse
Affiliation(s)
- L Biancone
- Division of Nephrology Dialysis and Transplantation, Department of Internal Medicine, San Giovanni Battista Hospital and University of Torino, Italy.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
The potential benefits of rapamycin on renal function, tolerance, fibrosis, and malignancy following transplantation. Kidney Int 2010; 78:1075-9. [PMID: 20861822 DOI: 10.1038/ki.2010.324] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Use of the mammalian target of rapamycin (mTOR) inhibitor rapamycin in organ transplantation has evolved through different phases over the past two decades. After its discovery in the mid 1970s, antifungal and cytotoxic effects were the first of its properties to be explored, but the most significant advancement was found in its use as an immunosuppressive agent to reduce transplant rejection. This was viewed as an important step forward for immunosuppression, as early studies suggested that rapamycin was less nephrotoxic than calcineurin inhibitors (CNIs). Later, detrimental effects of rapamycin on kidney function were found in some patients. Nonetheless, a fascination with the mTOR pathway and its central role in multiple cellular processes has ensued. Among the potential positive clinically relevant effects is rapamycin's capacity to interfere with fibrotic processes that often accompany transplant rejection, and to influence the preferential development of immunological tolerance. A feature of increasing importance is that the mTOR pathway is central for vital aspects of tumor development, including angiogenesis and cell growth; rapamycin, therefore, has anticancer activities, which may prove critical in the fight against high cancer rates in transplant recipients. The final chapters defining the value of rapamycin have not been written yet, and indeed remain a work in progress. Only further research will reveal the full potential of rapamycin in organ transplantation.
Collapse
|