1
|
Rojas-Canales DM, Li JY, Makuei L, Gleadle JM. Compensatory renal hypertrophy following nephrectomy: When and how? Nephrology (Carlton) 2019; 24:1225-1232. [PMID: 30809888 DOI: 10.1111/nep.13578] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2019] [Indexed: 12/16/2022]
Abstract
Following surgical removal of one kidney, the other enlarges and increases its function. The mechanism for the sensing of this change and the growth is incompletely understood but begins within days and compensatory renal hypertrophy (CRH) is the dominant contributor to the growth. In many individuals undergoing nephrectomy for cancer or kidney donation this produces a substantial and helpful increase in renal function. Two main mechanisms have been proposed, one in which increased activity by the remaining kidney leads to hypertrophy, the second in which there is release of a kidney specific factor in response to a unilateral nephrectomy that initiates CRH. Whilst multiple growth factors and pathways such as the mTORC pathway have been implicated in experimental studies, their roles and the precise mechanism of CRH are not defined. Unrestrained hypoxia inducible factor activation in renal cancer promotes growth and may play an important role in driving CRH.
Collapse
Affiliation(s)
- Darling M Rojas-Canales
- College of Medicine and Public Health and Medicine, Flinders University, Adelaide, South Australia, Australia.,Department of Renal Medicine, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Jordan Y Li
- College of Medicine and Public Health and Medicine, Flinders University, Adelaide, South Australia, Australia.,Department of Renal Medicine, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Leek Makuei
- College of Medicine and Public Health and Medicine, Flinders University, Adelaide, South Australia, Australia
| | - Jonathan M Gleadle
- College of Medicine and Public Health and Medicine, Flinders University, Adelaide, South Australia, Australia.,Department of Renal Medicine, Flinders Medical Centre, Adelaide, South Australia, Australia
| |
Collapse
|
2
|
Brown AL, Fluitt MB, Ecelbarger CM. Mechanistic target of rapamycin: integrating growth factor and nutrient signaling in the collecting duct. Am J Physiol Renal Physiol 2018; 315:F413-F416. [PMID: 29846113 DOI: 10.1152/ajprenal.00170.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The renal collecting duct and other postmacula densa sites are the primary tubular regions for fine-tuning of electrolyte homeostasis in the body. A role for the mechanistic target of rapamycin (mTOR), a serine-threonine kinase, has recently been appreciated in this regulation. mTOR exists in two distinct multiprotein functional complexes, i.e., mTORC1 and mTORC2. Upregulation of mTORC1, by growth factors and amino acids, is associated with cell cycle regulation and hypertrophic changes. In contrast, mTORC2 has been demonstrated to have a role in regulating Na+ and K+ reabsorptive processes, including those downstream of insulin and serum- and glucocorticoid-regulated kinase (SGK). In addition, mTORC2 can upregulate mTORC1. A number of elegant in vitro and in vivo studies using cell systems and genetically modified mice have revealed mechanisms underlying activation of the epithelial Na+ channel (ENaC) and the renal outer medullary K+ channel (ROMK) by mTORC2. Overall, mTOR in its systematic integration of phosphorylative signaling facilitates the delicate balance of whole body electrolyte homeostasis in the face of changes in metabolic status. Thus, inappropriate regulation of renal mTOR has the potential to result in electrolyte disturbances, such as acidosis/alkalosis, hyponatremia, and hypertension. The goal of this minireview is to highlight the physiological role of mTOR in its complexes in regulating electrolyte homeostasis in the aldosterone-sensitive distal nephron.
Collapse
Affiliation(s)
- Aaron L Brown
- Department of Medicine, Georgetown University , Washington, District of Columbia
| | - Maurice B Fluitt
- Department of Medicine, Georgetown University , Washington, District of Columbia
| | - Carolyn M Ecelbarger
- Department of Medicine, Georgetown University , Washington, District of Columbia
| |
Collapse
|
3
|
Clotet S, Soler MJ, Riera M, Pascual J, Fang F, Zhou J, Batruch I, Vasiliou SK, Dimitromanolakis A, Barrios C, Diamandis EP, Scholey JW, Konvalinka A. Stable Isotope Labeling with Amino Acids (SILAC)-Based Proteomics of Primary Human Kidney Cells Reveals a Novel Link between Male Sex Hormones and Impaired Energy Metabolism in Diabetic Kidney Disease. Mol Cell Proteomics 2017; 16:368-385. [PMID: 28062795 DOI: 10.1074/mcp.m116.061903] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 01/04/2017] [Indexed: 01/15/2023] Open
Abstract
Male sex predisposes to many kidney diseases. Considering that androgens exert deleterious effects in a variety of cell types within the kidney, we hypothesized that dihydrotestosterone (DHT) would alter the biology of the renal tubular cell by inducing changes in the proteome. We employed stable isotope labeling with amino acids (SILAC) in an indirect spike-in fashion to accurately quantify the proteome in DHT- and 17β-estradiol (EST)-treated human proximal tubular epithelial cells (PTEC). Of the 5043 quantified proteins, 76 were differentially regulated. Biological processes related to energy metabolism were significantly enriched among DHT-regulated proteins. SILAC ratios of 3 candidates representing glycolysis, N-acetylglucosamine metabolism and fatty acid β-oxidation, namely glucose-6-phosphate isomerase (GPI), glucosamine-6-phosphate-N-acetyltransferase 1 (GNPNAT1), and mitochondrial trifunctional protein subunit alpha (HADHA), were verified in vitro. In vivo, renal GPI and HADHA protein expression was significantly increased in males. Furthermore, male sex was associated with significantly higher GPI, GNPNAT1, and HADHA kidney protein expression in two different murine models of diabetes. Enrichment analysis revealed a link between our DHT-regulated proteins and oxidative stress within the diabetic kidney. This finding was validated in vivo, as we observed increased oxidative stress levels in control and diabetic male kidneys, compared with females. This in depth quantitative proteomics study of human primary PTEC response to sex hormone administration suggests that male sex hormone stimulation results in perturbed energy metabolism in kidney cells, and that this perturbation results in increased oxidative stress in the renal cortex. The proteome-level changes associated with androgens may play a crucial role in the development of structural and functional changes in the diseased kidney. With our findings, we propose a possible link between diabetic and non-diabetic kidney disease progression and male sex hormone levels. Data are available via ProteomeXchange (https://www.ebi.ac.uk/pride/archive/) with identifier PXD003811.
Collapse
Affiliation(s)
- Sergi Clotet
- From the ‡Department of Nephrology, Hospital del Mar-Institut Hospital del Mar d'Investigacions Mèdiques, Barcelona, Spain, 08003; .,§Institute of Medical Sciences, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,**Division of Nephrology, University Health Network, Toronto, Ontario M5G 2N2, Canada
| | - Maria Jose Soler
- From the ‡Department of Nephrology, Hospital del Mar-Institut Hospital del Mar d'Investigacions Mèdiques, Barcelona, Spain, 08003
| | - Marta Riera
- From the ‡Department of Nephrology, Hospital del Mar-Institut Hospital del Mar d'Investigacions Mèdiques, Barcelona, Spain, 08003
| | - Julio Pascual
- From the ‡Department of Nephrology, Hospital del Mar-Institut Hospital del Mar d'Investigacions Mèdiques, Barcelona, Spain, 08003
| | - Fei Fang
- §Institute of Medical Sciences, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Joyce Zhou
- §Institute of Medical Sciences, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Ihor Batruch
- ¶Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario M5G 1W7, Canada
| | - Stella K Vasiliou
- ¶Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario M5G 1W7, Canada.,‖Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario M5S 1A8, Canada
| | - Apostolos Dimitromanolakis
- ¶Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario M5G 1W7, Canada
| | - Clara Barrios
- From the ‡Department of Nephrology, Hospital del Mar-Institut Hospital del Mar d'Investigacions Mèdiques, Barcelona, Spain, 08003
| | - Eleftherios P Diamandis
- ¶Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario M5G 1W7, Canada
| | - James W Scholey
- §Institute of Medical Sciences, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,**Division of Nephrology, University Health Network, Toronto, Ontario M5G 2N2, Canada
| | - Ana Konvalinka
- §Institute of Medical Sciences, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,**Division of Nephrology, University Health Network, Toronto, Ontario M5G 2N2, Canada
| |
Collapse
|
4
|
Barron L, Sun RC, Aladegbami B, Erwin CR, Warner BW, Guo J. Intestinal Epithelial-Specific mTORC1 Activation Enhances Intestinal Adaptation After Small Bowel Resection. Cell Mol Gastroenterol Hepatol 2016; 3:231-244. [PMID: 28275690 PMCID: PMC5331783 DOI: 10.1016/j.jcmgh.2016.10.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 10/18/2016] [Indexed: 01/21/2023]
Abstract
BACKGROUND & AIMS Intestinal adaptation is a compensatory response to the massive loss of small intestine after surgical resection. We investigated the role of intestinal epithelial cell-specific mammalian target of rapamycin complex 1 (i-mTORC1) in intestinal adaptation after massive small bowel resection (SBR). METHODS We performed 50% proximal SBR on mice to study adaptation. To manipulate i-mTORC1 activity, Villin-CreER transgenic mice were crossed with tuberous sclerosis complex (TSC)1flox/flox or Raptorflox/flox mice to inducibly activate or inactivate i-mTORC1 activity with tamoxifen. Western blot was used to confirm the activity of mTORC1. Crypt depth and villus height were measured to score adaptation. Immunohistochemistry was used to investigate differentiation and rates of crypt proliferation. RESULTS After SBR, mice treated with systemic rapamycin showed diminished structural adaptation, blunted crypt cell proliferation, and significant body weight loss. Activating i-mTORC1 via TSC1 deletion induced larger hyperproliferative crypts and disorganized Paneth cells without a significant change in villus height. After SBR, ablating TSC1 in intestinal epithelium induced a robust villus growth with much stronger crypt cell proliferation, but similar body weight recovery. Acute inactivation of i-mTORC1 through deletion of Raptor did not change crypt cell proliferation or mucosa structure, but significantly reduced lysozyme/matrix metalloproteinase-7-positive Paneth cell and goblet cell numbers, with increased enteroendocrine cells. Surprisingly, ablation of intestinal epithelial cell-specific Raptor after SBR did not affect adaptation or crypt proliferation, but dramatically reduced body weight recovery after surgery. CONCLUSIONS Systemic, but not intestinal-specific, mTORC1 is important for normal adaptation responses to SBR. Although not required, forced enterocyte mTORC1 signaling after resection causes an enhanced adaptive response.
Collapse
Key Words
- Differentiation
- EGF, epidermal growth factor
- IHC, immunohistochemistry
- MMP, matrix metalloproteinase
- PCR, polymerase chain reaction
- Raptor
- S6K, S6 kinase
- SBR, small bowel resection
- TAM, tamoxifen
- TSC, tuberous sclerosis complex
- TSC1
- WT, wild type
- i-TSC-/-, intestinal epithelial cell–specific tuberous sclerosis complex 1 null mice
- mTOR, mammalian target of rapamycin
- mTORC, mammalian target of rapamycin complex
- p-HH3, phosphorylated histone H3
Collapse
Affiliation(s)
| | | | | | | | | | - Jun Guo
- Correspondence Address correspondence to: Jun Guo, PhD, BJC Institute of Health Room 7118, 425 South Euclid Avenue, St. Louis, Missouri 63110. fax: (314) 747–0610.BJC Institute of Health Room 7118425 South Euclid AvenueSt. LouisMissouri 63110
| |
Collapse
|