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Hakimi S, Dutta P, Layton AT. Coupling of renal sodium and calcium transport: a modeling analysis of transporter inhibition and sex differences. Am J Physiol Renal Physiol 2023; 325:F536-F551. [PMID: 37615047 DOI: 10.1152/ajprenal.00145.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 08/17/2023] [Accepted: 08/17/2023] [Indexed: 08/25/2023] Open
Abstract
Ca2+ transport along the nephron occurs via specific transcellular and paracellular pathways and is coupled to the transport of other electrolytes. Notably, Na+ transport establishes an electrochemical gradient to drive Ca2+ reabsorption. Hence, alterations in renal Na+ handling, under pathophysiological conditions or pharmacological manipulations, can have major effects on Ca2+ transport. An important class of pharmacological agent is diuretics, which are commonly prescribed for the management of blood pressure and fluid balance. The pharmacological targets of diuretics generally directly facilitate Na+ transport but also indirectly affect renal Ca2+ handling. To better understand the underlying mechanisms, we developed a computational model of electrolyte transport along the superficial nephron in the kidney of a male and female rat. Sex differences in renal Ca2+ handling are represented. Model simulations predicted in the female rat nephron lower Ca2+ reabsorption in the proximal tubule and thick ascending limb, but higher reabsorption in the late distal convoluted tubule and connecting tubule, compared with the male nephron. The male rat kidney model yielded a higher urinary Ca2+ excretion than the female model, consistent with animal experiments. Model results indicated that along the proximal tubule and thick ascending limb, Ca2+ and Na+ transport occurred in parallel, but those processes were dissociated in the distal convoluted tubule. Additionally, we conducted simulations of inhibition of channels and transporters that play a major role in Na+ and Ca2+ transport. Simulation results revealed alterations in transepithelial Ca2+ transport, with differential effects among nephron segments and between the sexes.NEW & NOTEWORTHY The kidney plays an important role in the maintenance of whole body Ca2+ balance by regulating Ca2+ reabsorption and excretion. This computational modeling study provides insights into how Ca2+ transport along the nephron is coupled to Na+. Model results indicated that along the proximal tubule and thick ascending limb, Ca2+ and Na+ transport occur in parallel, but those processes were dissociated in the distal convoluted tubule. Simulations also revealed sex-specific responses to different pharmacological manipulations.
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Affiliation(s)
- Shervin Hakimi
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
| | - Pritha Dutta
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
| | - Anita T Layton
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
- Department of Biology, Cheriton School of Computer Science, and School of Pharmacology, University of Waterloo, Waterloo, Ontario, Canada
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2
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Ehret E, Stroh S, Auberson M, Ino F, Jäger Y, Maillard M, Szabo R, Bugge TH, Frateschi S, Hummler E. Kidney-Specific Membrane-Bound Serine Proteases CAP1/Prss8 and CAP3/St14 Affect ENaC Subunit Abundances but Not Its Activity. Cells 2023; 12:2342. [PMID: 37830556 PMCID: PMC10572026 DOI: 10.3390/cells12192342] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/06/2023] [Accepted: 09/12/2023] [Indexed: 10/14/2023] Open
Abstract
The serine proteases CAP1/Prss8 and CAP3/St14 are identified as ENaC channel-activating proteases in vitro, highly suggesting that they are required for proteolytic activation of ENaC in vivo. The present study tested whether CAP3/St14 is relevant for renal proteolytic ENaC activation and affects ENaC-mediated Na+ absorption following Na+ deprivation conditions. CAP3/St14 knockout mice exhibit a significant decrease in CAP1/Prss8 protein expression with altered ENaC subunit and decreased pNCC protein abundances but overall maintain sodium balance. RNAscope-based analyses reveal co-expression of CAP3/St14 and CAP1/Prss8 with alpha ENaC in distal tubules of the cortex from wild-type mice. Double CAP1/Prss8; CAP3/St14-deficiency maintained Na+ and K+ balance on a Na+-deprived diet, restored ENaC subunit protein abundances but showed reduced NCC activity under Na+ deprivation. Overall, our data clearly show that CAP3/St14 is not required for direct proteolytic activation of ENaC but for its protein abundance. Our study reveals a complex regulation of ENaC by these serine proteases on the expression level rather than on its proteolytic activation.
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Affiliation(s)
- Elodie Ehret
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, 1011 Lausanne, Switzerland; (E.E.)
- National Center of Competence in Research “Kidney.CH”, 1011 Lausanne, Switzerland
| | - Sévan Stroh
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, 1011 Lausanne, Switzerland; (E.E.)
| | - Muriel Auberson
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, 1011 Lausanne, Switzerland; (E.E.)
| | - Frédérique Ino
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, 1011 Lausanne, Switzerland; (E.E.)
- Department of Medicine, University of Geneva, 1211 Geneva, Switzerland
| | - Yannick Jäger
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, 1011 Lausanne, Switzerland; (E.E.)
- Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Marc Maillard
- Service of Nephrology, Department of Medicine, Lausanne University Hospital (CHUV), 1005 Lausanne, Switzerland
| | - Roman Szabo
- National Institutes of Health/NIDCR, Bethesda, MD 20892, USA
| | - Thomas H. Bugge
- National Institutes of Health/NIDCR, Bethesda, MD 20892, USA
| | - Simona Frateschi
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, 1011 Lausanne, Switzerland; (E.E.)
| | - Edith Hummler
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, 1011 Lausanne, Switzerland; (E.E.)
- National Center of Competence in Research “Kidney.CH”, 1011 Lausanne, Switzerland
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3
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Matsubara A, Miyashita T, Nakashima K, Mori N, Song SY, Hoshikawa H. Low-salt diet increases mRNA expression of aldosterone-regulated transporters in the intermediate portion of the endolymphatic sac. Pflugers Arch 2022; 474:505-515. [PMID: 35112133 DOI: 10.1007/s00424-021-02661-9] [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: 07/09/2021] [Revised: 12/08/2021] [Accepted: 12/23/2021] [Indexed: 11/29/2022]
Abstract
The endolymphatic sac is a small sac-shaped organ at the end of the membranous labyrinth of the inner ear. The endolymphatic sac absorbs the endolymph, in which the ion balance is crucial for inner ear homeostasis. Of the three sections of the endolymphatic sac, the intermediate portion is the center of endolymph absorption, particularly sodium transport, and is thought to be regulated by aldosterone. Disorders of the endolymphatic sac may cause an excess of endolymph (endolymphatic hydrops), a histological observation in Meniere's disease. A low-salt diet is an effective treatment for Meniere's disease, and is based on the assumption that the absorption of endolymph in the endolymphatic sac abates endolymphatic hydrops through a physiological increase in aldosterone level. However, the molecular basis of endolymph absorption in each portion of the endolymphatic sac is largely unknown because of difficulties in gene expression analysis, resulting from its small size and intricate structure. The present study combined reverse transcription-quantitative polymerase chain reaction and laser capture microdissection techniques to analyze the difference of gene expression of the aldosterone-controlled epithelial Na+ channel, thiazide-sensitive Na+-Cl- cotransporter, and Na+, K+-ATPase genes in the three individual portions of the endolymphatic sac in a rat model. A low-salt diet increased the expression of aldosterone-controlled ion transporters, particularly in the intermediate portion of the endolymphatic sac. Our findings will contribute to the understanding of the physiological function of the endolymphatic sac and the pathophysiology of Meniere's disease.
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Affiliation(s)
- Ai Matsubara
- Department of Otolaryngology, Faculty of Medicine, Kagawa University, Ikenobe 1750-1, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan.
| | - Takenori Miyashita
- Department of Otolaryngology, Faculty of Medicine, Kagawa University, Ikenobe 1750-1, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan
| | - Kentaro Nakashima
- Institute of Neuroscience, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki, Kagawa, Japan
| | - Nozomu Mori
- Department of Otolaryngology, Faculty of Medicine, Kagawa University, Ikenobe 1750-1, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan
| | - Si-Young Song
- Institute of Neuroscience, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki, Kagawa, Japan
| | - Hiroshi Hoshikawa
- Department of Otolaryngology, Faculty of Medicine, Kagawa University, Ikenobe 1750-1, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan
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4
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Mo S, Cui Y, Sun K, Wang H, Peng X, Ou L, Lei X, Huang M, Mei W, Xin L, He H, Peng B, Tian Y, Wang P, Li X, Zhang R, Zhu X. High sodium chloride affects BMP-7 and 1α-hydroxylase levels through NCC and CLC-5 in NRK-52E cells. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 225:112762. [PMID: 34530263 DOI: 10.1016/j.ecoenv.2021.112762] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 09/01/2021] [Accepted: 09/05/2021] [Indexed: 06/13/2023]
Abstract
A diet high in sodium chloride (NaCl) can affect renal function damage and increase urinary calcium excretion, leading to bone loss. in renal tubules, Na-Cl co-transporter (NCC) and chloride channel 5 (CLC-5) are involved in regulating urinary calcium excretion. In addition, some cytokines, such as Bone morphogenetic protein 7 (BMP-7) and 1α-hydroxylase, are synthesized by renal tubules, which target on bone and play important roles on bone metabolism. However, the specific mechanisms between NaCl and these ion channels or cytokines still need investigations from many aspects. This study, in culture normal rat renal tubular epithelial NRK-52E cells, showed that high concentrations of NaCl significantly inhibited the cell viability and increased the cell apoptosis. High concentration of NaCl reduce bone mineral density (BMD), as demonstrated by the significantly increased mRNA and protein levels of NCC and osteopontin (OPN), but decreased the levels of CLC-5, BMP-7, and 1α-hydroxylase. In addition, we found that ovariectomized (OVX) rats on a high-salt diet for 12 weeks had altered levels of these indices in the renal cortices. Moreover, the BMD in fourth and fifth lumbar vertebra (LV4 and 5) and femurs were significantly decreased and bone microstructure was destroyed of these rats. We also demonstrated that high concentration of NaCl enhanced the inhibition of these cytokines which is beneficial to increase BMD, induced by modulating ion channels NCC and CLC-5. In conclusion, our results indicate that high concentration of NaCl reduce BMD by regulating ion channels NCC and CLC-5.
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Affiliation(s)
- Shu Mo
- The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong 510630, PR China; College of Traditional Chinese Medicine, Jinan University, Guangzhou, Guangdong 510630, PR China; Shenzhen Hospital of Traditional Chinese Medicine, Shenzhen, Guangdong, 518000, PR China
| | - Yan Cui
- College of Traditional Chinese Medicine, Jinan University, Guangzhou, Guangdong 510630, PR China
| | - Kehuan Sun
- College of Traditional Chinese Medicine, Jinan University, Guangzhou, Guangdong 510630, PR China
| | - Haixia Wang
- College of Traditional Chinese Medicine, Jinan University, Guangzhou, Guangdong 510630, PR China
| | - Xunqian Peng
- College of Traditional Chinese Medicine, Jinan University, Guangzhou, Guangdong 510630, PR China
| | - Ling Ou
- College of Pharmacy, Jinan University, Guangzhou, Guangdong 510630, PR China
| | - Xiaojun Lei
- College of Clinical Medicine, Jinan University, Guangzhou, Guangdong 510630, PR China
| | - Mengtian Huang
- College of Clinical Medicine, Jinan University, Guangzhou, Guangdong 510630, PR China
| | - Wenhui Mei
- College of Traditional Chinese Medicine, Jinan University, Guangzhou, Guangdong 510630, PR China
| | - Ling Xin
- College of Traditional Chinese Medicine, Jinan University, Guangzhou, Guangdong 510630, PR China
| | - Haibing He
- College of Pharmacy, Jinan University, Guangzhou, Guangdong 510630, PR China
| | - Bojia Peng
- College of Pharmacy, Jinan University, Guangzhou, Guangdong 510630, PR China
| | - Ya Tian
- College of Pharmacy, Jinan University, Guangzhou, Guangdong 510630, PR China
| | - Panpan Wang
- The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong 510630, PR China; Cancer research Institution, Jinan University, Guangzhou, Guangdong, 510630, PR China; Guangdong Provincial Key Laboratory of Traditional Chinese Medicine Informatization, Guangzhou, Guangdong, 510630, PR China
| | - Xiaoyun Li
- College of Traditional Chinese Medicine, Jinan University, Guangzhou, Guangdong 510630, PR China; Guangdong Provincial Key Laboratory of Traditional Chinese Medicine Informatization, Guangzhou, Guangdong, 510630, PR China
| | - Ronghua Zhang
- College of Traditional Chinese Medicine, Jinan University, Guangzhou, Guangdong 510630, PR China; College of Pharmacy, Jinan University, Guangzhou, Guangdong 510630, PR China; Cancer research Institution, Jinan University, Guangzhou, Guangdong, 510630, PR China; Guangdong Provincial Key Laboratory of Traditional Chinese Medicine Informatization, Guangzhou, Guangdong, 510630, PR China
| | - Xiaofeng Zhu
- The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong 510630, PR China; Guangdong Provincial Key Laboratory of Traditional Chinese Medicine Informatization, Guangzhou, Guangdong, 510630, PR China.
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5
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Liu LP, Gholam MF, Elshikha AS, Kawakibi T, Elmoujahid N, Moussa HH, Song S, Alli AA. Transgenic Mice Overexpressing Human Alpha-1 Antitrypsin Exhibit Low Blood Pressure and Altered Epithelial Transport Mechanisms in the Inactive and Active Cycles. Front Physiol 2021; 12:710313. [PMID: 34630137 PMCID: PMC8493122 DOI: 10.3389/fphys.2021.710313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 08/20/2021] [Indexed: 11/13/2022] Open
Abstract
Human alpha-1 antitrypsin (hAAT) is a versatile protease inhibitor, but little is known about its targets in the aldosterone-sensitive distal nephron and its role in electrolyte balance and blood pressure control. We analyzed urinary electrolytes, osmolality, and blood pressure from hAAT transgenic (hAAT-Tg) mice and C57B/6 wild-type control mice maintained on either a normal salt or high salt diet. Urinary sodium, potassium, and chloride concentrations as well as urinary osmolality were lower in hAAT-Tg mice maintained on a high salt diet during both the active and inactive cycles. hAAT-Tg mice showed a lower systolic blood pressure compared to C57B6 mice when maintained on a normal salt diet but this was not observed when they were maintained on a high salt diet. Cathepsin B protein activity was less in hAAT-Tg mice compared to wild-type controls. Protein expression of the alpha subunit of the sodium epithelial channel (ENaC) alpha was also reduced in the hAAT-Tg mice. Natriuretic peptide receptor C (NPRC) protein expression in membrane fractions of the kidney cortex was reduced while circulating levels of atrial natriuretic peptide (ANP) were greater in hAAT-Tg mice compared to wild-type controls. This study characterizes the electrolyte and blood pressure phenotype of hAAT-Tg mice during the inactive and active cycles and investigates the mechanism by which ENaC activation is inhibited in part by a mechanism involving decreased cathepsin B activity and increased ANP levels in the systemic circulation.
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Affiliation(s)
- Lauren P Liu
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, FL, United States
| | - Mohammed F Gholam
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, FL, United States
| | - Ahmed Samir Elshikha
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL, United States
| | - Tamim Kawakibi
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, FL, United States
| | - Nasseem Elmoujahid
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, FL, United States
| | - Hassan H Moussa
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, FL, United States
| | - Sihong Song
- Department of Pharmaceutics, University of Florida College of Medicine, Gainesville, FL, United States
| | - Abdel A Alli
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, FL, United States.,Division of Nephrology, Hypertension, and Renal Transplantation, Department of Medicine, University of Florida College of Medicine, Gainesville, FL, United States
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6
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Soares AG, Contreras J, Archer CR, Mironova E, Berdeaux R, Stockand JD, Abd El-Aziz TM. Stimulation of the Epithelial Na + Channel in Renal Principal Cells by Gs-Coupled Designer Receptors Exclusively Activated by Designer Drugs. Front Physiol 2021; 12:725782. [PMID: 34512393 PMCID: PMC8425396 DOI: 10.3389/fphys.2021.725782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 07/28/2021] [Indexed: 11/29/2022] Open
Abstract
The activity of the Epithelial Na+ Channel (ENaC) in renal principal cells (PC) fine-tunes sodium excretion and consequently, affects blood pressure. The Gs-adenylyl cyclase-cAMP signal transduction pathway is believed to play a central role in the normal control of ENaC activity in PCs. The current study quantifies the importance of this signaling pathway to the regulation of ENaC activity in vivo using a knock-in mouse that has conditional expression of Gs-DREADD (designer receptors exclusively activated by designer drugs; GsD) in renal PCs. The GsD mouse also contains a cAMP response element-luciferase reporter transgene for non-invasive bioluminescence monitoring of cAMP signaling. Clozapine N-oxide (CNO) was used to selectively and temporally stimulate GsD. Treatment with CNO significantly increased luciferase bioluminescence in the kidneys of PC-specific GsD but not control mice. CNO also significantly increased the activity of ENaC in principal cells in PC-specific GsD mice compared to untreated knock-in mice and CNO treated littermate controls. The cell permeable cAMP analog, 8-(4-chlorophenylthio)adenosine 3′,5′-cyclic monophosphate, significantly increased the activity and expression in the plasma membrane of recombinant ENaC expressed in CHO and COS-7 cells, respectively. Treatment of PC-specific GsD mice with CNO rapidly and significantly decreased urinary Na+ excretion compared to untreated PC-specific GsD mice and treated littermate controls. This decrease in Na+ excretion in response to CNO in PC-specific GsD mice was similar in magnitude and timing as that induced by the selective vasopressin receptor 2 agonist, desmopressin, in wild type mice. These findings demonstrate for the first time that targeted activation of Gs signaling exclusively in PCs is sufficient to increase ENaC activity and decrease dependent urinary Na+ excretion in live animals.
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Affiliation(s)
- Antonio G Soares
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Jorge Contreras
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Crystal R Archer
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Elena Mironova
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Rebecca Berdeaux
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - James D Stockand
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Tarek Mohamed Abd El-Aziz
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States.,Zoology Department, Faculty of Science, Minia University, Minya, Egypt
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7
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Abd El-Aziz TM, Soares AG, Mironova E, Boiko N, Kaur A, Archer CR, Stockand JD, Berman JM. Mechanisms and consequences of casein kinase II and ankyrin-3 regulation of the epithelial Na + channel. Sci Rep 2021; 11:14600. [PMID: 34272444 PMCID: PMC8285517 DOI: 10.1038/s41598-021-94118-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 07/01/2021] [Indexed: 01/21/2023] Open
Abstract
Activity of the Epithelial Na+ Channel (ENaC) in the distal nephron fine-tunes renal sodium excretion. Appropriate sodium excretion is a key factor in the regulation of blood pressure. Consequently, abnormalities in ENaC function can cause hypertension. Casein Kinase II (CKII) phosphorylates ENaC. The CKII phosphorylation site in ENaC resides within a canonical "anchor" ankyrin binding motif. CKII-dependent phosphorylation of ENaC is necessary and sufficient to increase channel activity and is thought to influence channel trafficking in a manner that increases activity. We test here the hypothesis that phosphorylation of ENaC by CKII within an anchor motif is necessary for ankyrin-3 (Ank-3) regulation of the channel, which is required for normal channel locale and function, and the proper regulation of renal sodium excretion. This was addressed using a fluorescence imaging strategy combining total internal reflection fluorescence (TIRF) microscopy with fluorescence recovery after photobleaching (FRAP) to quantify ENaC expression in the plasma membrane in living cells; and electrophysiology to quantify ENaC activity in split-open collecting ducts from principal cell-specific Ank-3 knockout mice. Sodium excretion studies also were performed in parallel in this knockout mouse. In addition, we substituted a key serine residue in the consensus CKII site in β-ENaC with alanine to abrogate phosphorylation and disrupt the anchor motif. Findings show that disrupting CKII signaling decreases ENaC activity by decreasing expression in the plasma membrane. In the principal cell-specific Ank-3 KO mouse, ENaC activity and sodium excretion were significantly decreased and increased, respectively. These results are consistent with CKII phosphorylation of ENaC functioning as a "switch" that favors Ank-3 binding to increase channel activity.
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Affiliation(s)
- Tarek Mohamed Abd El-Aziz
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center At San Antonio, San Antonio, TX, 78229-3900, USA
- Zoology Department, Faculty of Science, Minia University, El-Minia, 61519, Egypt
| | - Antonio G Soares
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center At San Antonio, San Antonio, TX, 78229-3900, USA
| | - Elena Mironova
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center At San Antonio, San Antonio, TX, 78229-3900, USA
| | - Nina Boiko
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center At San Antonio, San Antonio, TX, 78229-3900, USA
| | - Amanpreet Kaur
- Department of Biochemistry, University of Washington, Seattle, Washington, 98195, USA
| | - Crystal R Archer
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center At San Antonio, San Antonio, TX, 78229-3900, USA
| | - James D Stockand
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center At San Antonio, San Antonio, TX, 78229-3900, USA.
| | - Jonathan M Berman
- Department of Basic Science, New York Institute of Technology College of Osteopathic Medicine at Arkansas State University, Jonesboro, AR, 72401, USA
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8
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Li Z, Song T, Yong J, Kuang R. Imputation of spatially-resolved transcriptomes by graph-regularized tensor completion. PLoS Comput Biol 2021; 17:e1008218. [PMID: 33826608 PMCID: PMC8055040 DOI: 10.1371/journal.pcbi.1008218] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 04/19/2021] [Accepted: 03/19/2021] [Indexed: 12/02/2022] Open
Abstract
High-throughput spatial-transcriptomics RNA sequencing (sptRNA-seq) based on in-situ capturing technologies has recently been developed to spatially resolve transcriptome-wide mRNA expressions mapped to the captured locations in a tissue sample. Due to the low RNA capture efficiency by in-situ capturing and the complication of tissue section preparation, sptRNA-seq data often only provides an incomplete profiling of the gene expressions over the spatial regions of the tissue. In this paper, we introduce a graph-regularized tensor completion model for imputing the missing mRNA expressions in sptRNA-seq data, namely FIST, Fast Imputation of Spatially-resolved transcriptomes by graph-regularized Tensor completion. We first model sptRNA-seq data as a 3-way sparse tensor in genes (p-mode) and the (x, y) spatial coordinates (x-mode and y-mode) of the observed gene expressions, and then consider the imputation of the unobserved entries or fibers as a tensor completion problem in Canonical Polyadic Decomposition (CPD) form. To improve the imputation of highly sparse sptRNA-seq data, we also introduce a protein-protein interaction network to add prior knowledge of gene functions, and a spatial graph to capture the the spatial relations among the capture spots. The tensor completion model is then regularized by a Cartesian product graph of protein-protein interaction network and the spatial graph to capture the high-order relations in the tensor. In the experiments, FIST was tested on ten 10x Genomics Visium spatial transcriptomic datasets of different tissue sections with cross-validation among the known entries in the imputation. FIST significantly outperformed the state-of-the-art methods for single-cell RNAseq data imputation. We also demonstrate that both the spatial graph and PPI network play an important role in improving the imputation. In a case study, we further analyzed the gene clusters obtained from the imputed gene expressions to show that the imputations by FIST indeed capture the spatial characteristics in the gene expressions and reveal functions that are highly relevant to three different kinds of tissues in mouse kidney. Biological tissues are composed of different types of structurally organized cell units playing distinct functional roles. The exciting new spatial gene expression profiling methods have enabled the analysis of spatially resolved transcriptomes to understand the spatial and functional characteristics of these cells in the context of eco-environment of tissue. Due to the technical limitations, spatial transcriptomics data suffers from only sparsely measured mRNAs by in-situ capture and possibly missing spots in tissue regions that entirely failed fixing and permeabilizing RNAs. Our method, FIST (Fast Imputation of Spatially-resolved transcriptomes by graph-regularized Tensor completion), focuses on the spatial and high-sparsity nature of spatial transcriptomics data by modeling the data as a 3-way gene-by-(x, y)-location tensor and a product graph of a spatial graph and a protein-protein interaction network. Our comprehensive evaluation of FIST on ten 10x Genomics Visium spatial genomics datasets and comparison with the methods for single-cell RNA sequencing data imputation demonstrate that FIST is a better method more suitable for spatial gene expression imputation. Overall, we found FIST a useful new method for analyzing spatially resolved gene expressions based on novel modeling of spatial and functional information.
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Affiliation(s)
- Zhuliu Li
- Department of Computer Science and Engineering, University of Minnesota Twin Cities, Minneapolis, Minnesota, United States of America
| | - Tianci Song
- Department of Computer Science and Engineering, University of Minnesota Twin Cities, Minneapolis, Minnesota, United States of America
| | - Jeongsik Yong
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Twin Cities, Minneapolis, Minnesota, United States of America
| | - Rui Kuang
- Department of Computer Science and Engineering, University of Minnesota Twin Cities, Minneapolis, Minnesota, United States of America
- * E-mail:
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Olde Hanhof CJA, Yousef Yengej FA, Rookmaaker MB, Verhaar MC, van der Wijst J, Hoenderop JG. Modeling Distal Convoluted Tubule (Patho)Physiology: An Overview of Past Developments and an Outlook Toward the Future. Tissue Eng Part C Methods 2021; 27:200-212. [PMID: 33544049 DOI: 10.1089/ten.tec.2020.0345] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The kidneys are essential for maintaining electrolyte homeostasis. Blood electrolyte composition is controlled by active reabsorption and secretion processes in dedicated segments of the kidney tubule. Specifically, the distal convoluted tubule (DCT) and connecting tubule are important for regulating the final excretion of sodium, magnesium, and calcium. Studies unravelling the specific function of these segments have greatly improved our understanding of DCT (patho)physiology. Over the years, experimental models used to study the DCT have changed and the field has advanced from early dissection studies with rats and rabbits to the use of various transgenic mouse models. Developments in dissection techniques and cell culture methods have resulted in immortalized mouse DCT cell lines and made it possible to specifically obtain DCT fragments for ex vivo studies. However, we still do not fully understand the complex (patho)physiology of this segment and there is need for advanced human DCT models. Recently, kidney organoids and tubuloids have emerged as new complex cell models that provide excellent opportunities for physiological studies, disease modeling, drug discovery, and even personalized medicine in the future. This review presents an overview of cell models used to study the DCT and provides an outlook on kidney organoids and tubuloids as model for DCT (patho)physiology. Impact statement This study provides a detailed overview of past and future developments on cell models used to study kidney (patho)physiology and specifically the distal convoluted tubule (DCT) segment. Hereby, we highlight the need for an advanced human cell model of this segment and summarize recent advances in the field of kidney organoids and tubuloids with a focus on DCT properties. The findings reported in this review are significant for future developments toward an advanced human model of the DCT that will help to increase our understanding of DCT (patho)physiology.
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Affiliation(s)
- Charlotte J A Olde Hanhof
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Fjodor A Yousef Yengej
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences, Utrecht, The Netherlands.,Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Maarten B Rookmaaker
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marianne C Verhaar
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost G Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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10
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Franken GAC, Adella A, Bindels RJM, de Baaij JHF. Mechanisms coupling sodium and magnesium reabsorption in the distal convoluted tubule of the kidney. Acta Physiol (Oxf) 2021; 231:e13528. [PMID: 32603001 PMCID: PMC7816272 DOI: 10.1111/apha.13528] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 05/29/2020] [Accepted: 06/22/2020] [Indexed: 02/06/2023]
Abstract
Hypomagnesaemia is a common feature of renal Na+ wasting disorders such as Gitelman and EAST/SeSAME syndrome. These genetic defects specifically affect Na+ reabsorption in the distal convoluted tubule, where Mg2+ reabsorption is tightly regulated. Apical uptake via TRPM6 Mg2+ channels and basolateral Mg2+ extrusion via a putative Na+ -Mg2+ exchanger determines Mg2+ reabsorption in the distal convoluted tubule. However, the mechanisms that explain the high incidence of hypomagnesaemia in patients with Na+ wasting disorders of the distal convoluted tubule are largely unknown. In this review, we describe three potential mechanisms by which Mg2+ reabsorption in the distal convoluted tubule is linked to Na+ reabsorption. First, decreased activity of the thiazide-sensitive Na+ /Cl- cotransporter (NCC) results in shortening of the segment, reducing the Mg2+ reabsorption capacity. Second, the activity of TRPM6 and NCC are determined by common regulatory pathways. Secondary effects of NCC dysregulation such as hormonal imbalance, therefore, might disturb TRPM6 expression. Third, the basolateral membrane potential, maintained by the K+ permeability and Na+ -K+ -ATPase activity, provides the driving force for Na+ and Mg2+ extrusion. Depolarisation of the basolateral membrane potential in Na+ wasting disorders of the distal convoluted tubule may therefore lead to reduced activity of the putative Na+ -Mg2+ exchanger SLC41A1. Elucidating the interconnections between Mg2+ and Na+ transport in the distal convoluted tubule is hampered by the currently available models. Our analysis indicates that the coupling of Na+ and Mg2+ reabsorption may be multifactorial and that advanced experimental models are required to study the molecular mechanisms.
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Affiliation(s)
- Gijs A. C. Franken
- Department of PhysiologyRadboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenthe Netherlands
| | - Anastasia Adella
- Department of PhysiologyRadboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenthe Netherlands
| | - René J. M. Bindels
- Department of PhysiologyRadboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenthe Netherlands
| | - Jeroen H. F. de Baaij
- Department of PhysiologyRadboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenthe Netherlands
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11
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Rotem-Grunbaum B, Landau D. Genetic renal disease classification by hormonal axes. Pediatr Nephrol 2020; 35:2211-2219. [PMID: 31828468 DOI: 10.1007/s00467-019-04437-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 11/23/2019] [Accepted: 11/26/2019] [Indexed: 12/31/2022]
Abstract
The kidneys, which regulate many homeostatic pathways, are also a major endocrinological target organ. Many genetic renal diseases can be classified according to the affected protein along such endocrinological pathways. In this review, we examine the hypothesis that a more severe phenotype is expected as the affected protein is located more distally along such pathways. Thus, the location of a defect along its endocrinological pathway should be taken into consideration, in addition to the mutation type, when assessing genetic renal disease severity.
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Affiliation(s)
- Bar Rotem-Grunbaum
- Department of Pediatrics B, Schneider Children's Medical Center of Israel, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Daniel Landau
- Department of Pediatrics B, Schneider Children's Medical Center of Israel, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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12
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Yang J, Xiong X, Xiao Y, Wei L, Li L, Yang M, Han Y, Zhao H, Li C, Jiang N, Xiong S, Zeng L, Zhou Z, Liu S, Wang N, Fan Y, Sun L. The single nucleotide polymorphism rs11643718 in SLC12A3 is associated with the development of diabetic kidney disease in Chinese people with type 2 diabetes. Diabet Med 2020; 37:1879-1889. [PMID: 32634861 PMCID: PMC7589246 DOI: 10.1111/dme.14364] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 06/13/2020] [Accepted: 07/01/2020] [Indexed: 01/05/2023]
Abstract
AIMS To examine the association between 24 literature-based single nucleotide polymorphisms and diabetic kidney disease in Chinese people with type 2 diabetes. METHODS AND RESULTS Twenty-four candidate diabetic kidney disease-susceptible single nucleotide polymorphisms were genotyped in 208 participants with type 2 diabetes and diabetic kidney disease and 200 participants with type 2 diabetes without diabetic kidney disease (case and control groups, respectively), together with 206 healthy participants using MassARRAY. Rs11643718 in the SLC12A3 gene was associated with diabetic kidney disease in the recessive model after adjusting for confounding factors, such as age and gender (adjusted odds ratio 2.056, 95% CI 1.120-3.776; P = 0.020). Meta-analyses further confirmed the association (P = 0.002). In addition, participants with the GG genotype had worse renal function and more albuminuria than those with the AA+AG genotype (P < 0.05). Renal section immunohistochemistry was conducted in participants with type 2 diabetes, diabetic kidney disease and AA+AG or GG genotypes and in participants with glomerular minor lesions. Together with data from the Nephroseq database, it was shown that the abundance of SLC12A3 was reduced in patients with the GG genotype, while elevated expression of SLC12A3 was associated with better renal function. In addition, rs10951509 and rs1345365 in ELMO1, which were determined to be in high linkage disequilibrium by SHEsis software, were also associated with diabetic kidney disease (adjusted P = 0.010 and 0.015, respectively). CONCLUSIONS The G allele and GG genotype of SLC12A3 rs11643718 are associated with the development of diabetic kidney disease in a Chinese population with type 2 diabetes.
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Affiliation(s)
- J.‐F. Yang
- Department of NephrologyHunan Key Laboratory of Kidney Disease and Blood PurificationSecond Xiangya Hospital at Central South UniversityChangshaChina
| | - X.‐F. Xiong
- Department of NephrologyHunan Key Laboratory of Kidney Disease and Blood PurificationSecond Xiangya Hospital at Central South UniversityChangshaChina
| | - Y. Xiao
- Department of NephrologyHunan Key Laboratory of Kidney Disease and Blood PurificationSecond Xiangya Hospital at Central South UniversityChangshaChina
| | - L. Wei
- Department of NephrologyHunan Key Laboratory of Kidney Disease and Blood PurificationSecond Xiangya Hospital at Central South UniversityChangshaChina
| | - L. Li
- Department of NephrologyHunan Key Laboratory of Kidney Disease and Blood PurificationSecond Xiangya Hospital at Central South UniversityChangshaChina
| | - M. Yang
- Department of NephrologyHunan Key Laboratory of Kidney Disease and Blood PurificationSecond Xiangya Hospital at Central South UniversityChangshaChina
| | - Y.‐C. Han
- Department of NephrologyHunan Key Laboratory of Kidney Disease and Blood PurificationSecond Xiangya Hospital at Central South UniversityChangshaChina
| | - H. Zhao
- Department of NephrologyHunan Key Laboratory of Kidney Disease and Blood PurificationSecond Xiangya Hospital at Central South UniversityChangshaChina
| | - C.‐R. Li
- Department of NephrologyHunan Key Laboratory of Kidney Disease and Blood PurificationSecond Xiangya Hospital at Central South UniversityChangshaChina
| | - N. Jiang
- Department of NephrologyHunan Key Laboratory of Kidney Disease and Blood PurificationSecond Xiangya Hospital at Central South UniversityChangshaChina
| | - S. Xiong
- Department of NephrologyHunan Key Laboratory of Kidney Disease and Blood PurificationSecond Xiangya Hospital at Central South UniversityChangshaChina
| | - L.‐F. Zeng
- Department of NephrologyHunan Key Laboratory of Kidney Disease and Blood PurificationSecond Xiangya Hospital at Central South UniversityChangshaChina
| | - Z.‐G. Zhou
- National Clinical Research Centre for Metabolic Diseases Diabetes CentreDepartment of EndocrinologySecond Xiangya Hospital at Central South UniversityChangshaChina
| | - S.‐P. Liu
- National Clinical Research Centre for Metabolic Diseases Diabetes CentreDepartment of EndocrinologySecond Xiangya Hospital at Central South UniversityChangshaChina
| | - N.‐S. Wang
- Department of NephrologyShanghai Jiao Tong University Affiliated Sixth People's HospitalShanghaiChina
| | - Y. Fan
- Department of NephrologyShanghai Jiao Tong University Affiliated Sixth People's HospitalShanghaiChina
| | - L. Sun
- Department of NephrologyHunan Key Laboratory of Kidney Disease and Blood PurificationSecond Xiangya Hospital at Central South UniversityChangshaChina
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13
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Hu R, McDonough AA, Layton AT. Sex differences in solute transport along the nephrons: effects of Na + transport inhibition. Am J Physiol Renal Physiol 2020; 319:F487-F505. [PMID: 32744084 DOI: 10.1152/ajprenal.00240.2020] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Each day, ~1.7 kg of NaCl and 180 liters of water are reabsorbed by nephron segments in humans, with urinary excretion fine tuned to meet homeostatic requirements. These tasks are coordinated by a spectrum of renal Na+ transporters and channels. The goal of the present study was to investigate the extent to which inhibitors of transepithelial Na+ transport (TNa) along the nephron alter urinary solute excretion and how those effects may vary between male and female subjects. To accomplish that goal, we developed sex-specific multinephron models that represent detailed transcellular and paracellular transport processes along the nephrons of male and female rat kidneys. We simulated inhibition of Na+/H+ exchanger 3 (NHE3), bumetanide-sensitive Na+-K+-2Cl- cotransporter (NKCC2), Na+-Cl- cotransporter (NCC), and amiloride-sensitive epithelial Na+ channel (ENaC). NHE3 inhibition simulations predicted a substantially reduced proximal tubule TNa, and NKCC2 inhibition substantially reduced thick ascending limb TNa. Both gave rise to diuresis, natriuresis, and kaliuresis, with those effects stronger in female rats. While NCC inhibition was predicted to have only minor impact on renal TNa, it nonetheless had a notable effect of enhancing excretion of Na+, K+, and Cl-, particularly in female rats. Inhibition of ENaC was predicted to have opposite effects on the excretion of Na+ (increased) and K+ (decreased) and to have only a minor impact on whole kidney TNa. Unlike inhibition of other transporters, ENaC inhibition induced stronger natriuresis and diuresis in male rats than female rats. Overall, model predictions agreed well with measured changes in Na+ and K+ excretion in response to diuretics and Na+ transporter mutations.
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Affiliation(s)
- Rui Hu
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
| | - Alicia A McDonough
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Anita T Layton
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada.,Department of Biology, Cheriton School of Computer Science, and School of Pharmacology, University of Waterloo, Waterloo, Ontario, Canada
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14
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Xu H, Hashem A, Witasp A, Mencke R, Goldsmith D, Barany P, Bruchfeld A, Wernerson A, Carrero JJ, Olauson H. Fibroblast growth factor 23 is associated with fractional excretion of sodium in patients with chronic kidney disease. Nephrol Dial Transplant 2020; 34:2051-2057. [PMID: 30312430 DOI: 10.1093/ndt/gfy315] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 05/01/2018] [Accepted: 08/14/2018] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Recent studies suggest that the phosphaturic hormone fibroblast growth factor 23 (FGF23) is involved in regulation of renal sodium excretion and blood pressure. There is evidence of both direct effects via regulation of the sodium-chloride symporter (NCC) in the distal tubule, and indirect effects through interactions with the renin-angiotensin-aldosterone system. However, clinical data on the association between FGF23 and renal sodium regulation is lacking. Herein, we investigated the associations of FGF23 with renal sodium handling and blood pressure in non-dialysis CKD patients. METHODS This was a cross-sectional study encompassing 180 CKD patients Stage 1-5, undergoing renal biopsy. Plasma intact FGF23, 24-h urinary sodium excretion, fractional excretion of sodium (FENa) and blood pressure were measured at baseline. The association between FGF23 and renal sodium handling was explored by multivariate regression analysis. RESULTS The median age was 52.8 years, 60.6% were men and the median estimated glomerular filtration rate (eGFR) was 50.6 mL/min/1.73 m2. In univariate analysis, FGF23 was positively associated with FENa (Spearman's rho = 0.47; P < 0.001) and systolic blood pressure (rho = 0.17, P < 0.05), but not with plasma sodium, 24-h urinary sodium excretion or mean arterial blood pressure. The association between FGF23 and FENa remained significant after adjustment for potential confounders (multivariable adjusted β coefficient 0.60, P < 0.001). This association was stronger among the 107 individuals with eGFR <60 mL/min/1.73 m2 (β = 0.47, P = 0.04) and in the 73 individuals on any diuretics (β = 0.88, P < 0.001). Adjustment for measured GFR instead of eGFR did not alter the relationship. CONCLUSIONS FGF23 is independently associated with increased FENa in non-dialysis CKD patients. These data do not support the notion that FGF23 causes clinically significant sodium retention. Further studies are warranted to explore the mechanism underlying this association.
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Affiliation(s)
- Hong Xu
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Ali Hashem
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Anna Witasp
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Rik Mencke
- Division of Pathology, Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - David Goldsmith
- Department of Nephrology, Renal, Dialysis and Transplantation Unit, Guy's and St Thomas' Hospital, London, UK
| | - Peter Barany
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Annette Bruchfeld
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Annika Wernerson
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Juan-Jesus Carrero
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Hannes Olauson
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
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van der Wijst J, Belge H, Bindels RJM, Devuyst O. Learning Physiology From Inherited Kidney Disorders. Physiol Rev 2019; 99:1575-1653. [PMID: 31215303 DOI: 10.1152/physrev.00008.2018] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The identification of genes causing inherited kidney diseases yielded crucial insights in the molecular basis of disease and improved our understanding of physiological processes that operate in the kidney. Monogenic kidney disorders are caused by mutations in genes coding for a large variety of proteins including receptors, channels and transporters, enzymes, transcription factors, and structural components, operating in specialized cell types that perform highly regulated homeostatic functions. Common variants in some of these genes are also associated with complex traits, as evidenced by genome-wide association studies in the general population. In this review, we discuss how the molecular genetics of inherited disorders affecting different tubular segments of the nephron improved our understanding of various transport processes and of their involvement in homeostasis, while providing novel therapeutic targets. These include inherited disorders causing a dysfunction of the proximal tubule (renal Fanconi syndrome), with emphasis on epithelial differentiation and receptor-mediated endocytosis, or affecting the reabsorption of glucose, the handling of uric acid, and the reabsorption of sodium, calcium, and magnesium along the kidney tubule.
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Affiliation(s)
- Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Hendrica Belge
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Olivier Devuyst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
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16
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Freundlich M, Cuervo C, Abitbol CL. Fibroblast growth factor 23 and tubular sodium handling in young patients with incipient chronic kidney disease. Clin Kidney J 2019; 13:389-396. [PMID: 32699619 PMCID: PMC7367134 DOI: 10.1093/ckj/sfz081] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 05/28/2019] [Indexed: 12/15/2022] Open
Abstract
AbstractBackgroundExperimental studies have shown fibroblast growth factor 23 (FGF23)-mediated upregulation of the distal tubule sodium/chloride (Na+Cl−) co-transporter leading to increased Na reabsorption, volume expansion and hypertension. However, data on the associations of FGF23 with renal Na regulation and blood pressure (BP) are lacking in young CKD patients.MethodsFGF23 and other determinants of mineral metabolism, plasma renin activity (PRA), fractional excretion of Na (FENa) and BP, were analyzed at a single center in 60 patients aged 5–22 years with CKD Stages 1 (n = 33) and Stages 2–3 (n = 27) defined by cystatin C- and creatinine-based estimating equations (estimated glomerular filtration rate, eGFR). Associations between FGF23 and renal Na handling were explored by regression analysis.ResultsMedian FGF23 levels were higher in CKD Stages 2–3 versus CKD 1 (119 versus 79 RU/mL; P < 0.05), with hyperparathyroidism [parathyroid hormone (PTH) >69 pg/mL] in only few subjects with CKD Stages 2–3. Median FENa was comparable in both subgroups, but with proportionally more values above the reference mean (0.55%) in CKD Stages 2–3 and 3-fold higher (1.6%) in CKD Stage 3. PRA was higher in CKD Stages 2–3 (P < 0.05). Meanwhile in CKD Stage 1, FGF23 did not associate with FENa, and in CKD Stages 2–3 FGF23 associated positively with FENa (r = 0.4; P < 0.05) and PTH (r = 0.45; P < 0.05), and FENa associated with FE of phosphate (r = 0.6; P < 0.005). Neither FGF23 nor FENa was associated with systolic or diastolic BP in either subgroup. The negative association of eGFR by cystatin with FENa remained the strongest predictor of FENa by multivariable linear regression in CKD Stages 2–3.ConclusionsThe elevated FGF23, FENa and PRA and the positive association of FGF23 with FENa do not suggest FGF23-mediated increased tubular Na reabsorption and volume expansion as causing hypertension in young patients with incipient CKD.
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Affiliation(s)
- Michael Freundlich
- Division of Pediatric Nephrology, Jackson Memorial-Holtz Children’s Hospital, University of Miami, Miami, FL, USA
| | - Carlos Cuervo
- Division of Pediatric Nephrology, Jackson Memorial-Holtz Children’s Hospital, University of Miami, Miami, FL, USA
| | - Carolyn L Abitbol
- Division of Pediatric Nephrology, Jackson Memorial-Holtz Children’s Hospital, University of Miami, Miami, FL, USA
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17
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The role of distal tubule and collecting duct sodium reabsorption in sunitinib-induced hypertension. J Hypertens 2019; 36:892-903. [PMID: 29283974 DOI: 10.1097/hjh.0000000000001650] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Antiangiogenic receptor tyrosine kinase inhibitors (RTKI) induce arterial hypertension which may limit their use. Renal fractional sodium excretion (FENa) is reduced in early RTKI-induced hypertension, whereas fractional lithium excretion is unaltered. Therefore, we tested the hypothesis that activated distal tubule and collecting duct sodium reabsorption contributes to RTKI-induced hypertension. METHODS Amiloride-sensitive and hydrochlorothiazide (HCTZ)-sensitive fractional sodium reabsorption (FRNa) and renal epithelial sodium channel (ENaC) as well as sodium chloride cotransporter (NCC) abundances were determined in sunitinib-treated and control rats. The antihypertensive effects of amiloride and HCTZ were investigated by radiotelemery. RESULTS After 4 days of treatment, mean arterial pressure was 20 mmHg higher, FENa was lower (0.32 ± 0.08% vs. 0.65 ± 0.14%; P < 0.05), and renal medullary-ENaC protein abundance was higher in sunitinib-treated rats than in controls. Amiloride-sensitive FRNa was 2.37 ± 0.52% in sunitinib-treated rats vs. 2.66 ± 0.44% in controls (n.s.). HCTZ increased FENa by a similar magnitude without affecting amiloride-sensitive FRNa in both groups. After 14 days of treatment, renal medullary β-ENaC protein abundance was higher in rats that received sunitinib than in controls, whereas α-ENaC, γ-ENaC, and NCC abundances were similar in both groups. Amiloride and HCTZ reduced the sunitinib-induced mean arterial pressure rise by 8 ± 3 mmHg (P < 0.05) and 12 ± 2 mmHg (P < 0.05), respectively, without additive effects when combined. CONCLUSION ENaC-dependent and thiazide-sensitive sodium-retaining mechanisms are not overactive in sunitinib-induced hypertension but ENaC blockers and in particular thiazides may be suitable for its treatment.
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Layton AT, Vallon V. Renal tubular solute transport and oxygen consumption: insights from computational models. Curr Opin Nephrol Hypertens 2019; 27:384-389. [PMID: 30016311 DOI: 10.1097/mnh.0000000000000435] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
PURPOSE OF REVIEW To maintain electrolyte homeostasis, the kidneys reabsorb more than 99% of the filtered Na under physiological conditions, resulting in less than 1% of the filtered Na excreted in urine. In contrast, due to distal tubular secretion, urinary K output may exceed filtered load. This review focuses on a relatively new methodology for investigating renal epithelial transport, computational modelling and highlights recent insights regarding renal Na and K transport and O2 consumption under pathophysiological conditions, with a focus on nephrectomy. RECENT FINDINGS Recent modelling studies investigated the extent to which the adaptive response to nephrectomy, which includes elevation in single-nephron glomerular filtration rate and tubular transport capacity, may achieve balance but increases O2 consumption per nephron. Simulation results pointed to potential mechanisms in a hemi-nephrectomized rat that may attenuate the natriuresis response under K load, or that may augment the natriuretic, diuretic and kaliuretic effects of sodium glucose cotransporter 2 inhibition. SUMMARY Computational models provide a systemic approach for investigating system perturbations, such as those induced by drug administration or genetic alterations. Thus, computational models can be a great asset in data interpretation concerning (but not limited to) renal tubular transport and metabolism.
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Affiliation(s)
- Anita T Layton
- Department of Mathematics.,Department of Biomedical Engineering.,Department of Medicine, Duke University, Durham, North Carolina.,Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
| | - Volker Vallon
- Department of Medicine.,Department of Pharmacology, University of California, San Diego, La Jolla.,San Diego Veterans Affairs Healthcare System, San Diego, California, USA
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19
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Mironova E, Suliman F, Stockand JD. Renal Na + excretion consequent to pharmacogenetic activation of G q-DREADD in principal cells. Am J Physiol Renal Physiol 2019; 316:F758-F767. [PMID: 30724104 PMCID: PMC6483033 DOI: 10.1152/ajprenal.00612.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 01/31/2019] [Accepted: 01/31/2019] [Indexed: 02/07/2023] Open
Abstract
Stimulation of metabotropic Gq-coupled purinergic P2Y2 receptors decreases activity of the epithelial Na+ channel (ENaC) in renal principal cells of the distal nephron. The physiological consequences of P2Y2 receptor signaling disruption in the P2Y2 receptor knockout mouse are decreased Na+ excretion and increased arterial blood pressure. However, because of the global nature of this knockout model, the quantitative contribution of ENaC and distal nephron compared with that of upstream renal vascular and tubular elements to changes in urinary excretion and arterial blood pressure is obscure. Moreover, it is uncertain whether stimulation of P2Y2 receptor inhibition of ENaC is sufficient to drive renal (urinary) Na+ excretion (UNaV). Here, using a pharmacogenetic approach and selective agonism of the P2Y2 receptor, we test the sufficiency of targeted stimulation of Gq signaling in principal cells of the distal nephron and P2Y2 receptors to increase UNaV. Selective stimulation of the P2Y2 receptor with the ligand MRS2768 decreased ENaC activity in freshly isolated tubules (as assessed by patch-clamp electrophysiology) and increased UNaV (as assessed in metabolic cages). Similarly, selective agonism of hM3Dq-designer receptors exclusively activated by designer drugs (DREADD) restrictively expressed in principal cells of the distal nephron with clozapine- N-oxide decreased ENaC activity and, consequently, increased UNaV. Clozapine- N-oxide, when applied to control littermates, failed to affect ENaC and UNaV. This study represents the first use of pharmacogenetic (DREADD) technology in the renal tubule and demonstrated that selective activation of the P2Y2 receptor and Gq signaling in principal cells is sufficient to promote renal salt excretion.
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Affiliation(s)
- Elena Mironova
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio , San Antonio, Texas
| | - Faroug Suliman
- Division of Nephrology, Department of Internal Medicine, University of Michigan , Ann Arbor, Michigan
| | - James D Stockand
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio , San Antonio, Texas
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20
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Williams CR, Mistry M, Cheriyan AM, Williams JM, Naraine MK, Ellis CL, Mallick R, Mistry AC, Gooch JL, Ko B, Cai H, Hoover RS. Zinc deficiency induces hypertension by promoting renal Na + reabsorption. Am J Physiol Renal Physiol 2019; 316:F646-F653. [PMID: 30649891 DOI: 10.1152/ajprenal.00487.2018] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Zn2+ deficiency (ZnD) is a common comorbidity of many chronic diseases. In these settings, ZnD exacerbates hypertension. Whether ZnD alone is sufficient to alter blood pressure (BP) is unknown. To explore the role of Zn2+ in BP regulation, adult mice were fed a Zn2+-adequate (ZnA) or a Zn2+-deficient (ZnD) diet. A subset of ZnD mice were either returned to the ZnA diet or treated with hydrochlorothiazide (HCTZ), a Na+-Cl- cotransporter (NCC) inhibitor. To reduce intracellular Zn2+ in vitro, mouse distal convoluted tubule cells were cultured in N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN, a Zn2+ chelator)- or vehicle (DMSO)-containing medium. To replete intracellular Zn2+, TPEN-exposed cells were then cultured in Zn2+-supplemented medium. ZnD promoted a biphasic BP response, characterized by episodes of high BP. BP increases were accompanied by reduced renal Na+ excretion and NCC upregulation. These effects were reversed in Zn2+-replete mice. Likewise, HCTZ stimulated natriuresis and reversed BP increases. In vitro, Zn2+ depletion increased NCC expression. Furthermore, TPEN promoted NCC surface localization and Na+ uptake activity. Zn2+ repletion reversed TPEN effects on NCC. These data indicate that 1) Zn2+ contributes to BP regulation via modulation of renal Na+ transport, 2) renal NCC mediates ZnD-induced hypertension, and 3) NCC is a Zn2+-regulated transporter that is upregulated with ZnD. This study links dysregulated renal Na+ handling to ZnD-induced hypertension. Furthermore, NCC is identified as a novel mechanism by which Zn2+ regulates BP. Understanding the mechanisms of ZnD-induced BP dysregulation may have an important therapeutic impact on hypertension.
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Affiliation(s)
- Clintoria R Williams
- Division of Nephrology, Department of Medicine, and Department of Physiology, Emory University , Atlanta, Georgia.,Research Service, Atlanta Veterans Affairs Medical Center , Atlanta, Georgia.,Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, and College of Science and Mathematics, Wright State University , Dayton, Ohio
| | - Monisha Mistry
- Division of Nephrology, Department of Medicine, and Department of Physiology, Emory University , Atlanta, Georgia
| | - Aswathy M Cheriyan
- Division of Nephrology, Department of Medicine, and Department of Physiology, Emory University , Atlanta, Georgia
| | - Jasmine M Williams
- Division of Nephrology, Department of Medicine, and Department of Physiology, Emory University , Atlanta, Georgia
| | - Meagan K Naraine
- Division of Nephrology, Department of Medicine, and Department of Physiology, Emory University , Atlanta, Georgia
| | - Carla L Ellis
- Division of Nephrology, Department of Medicine, and Department of Physiology, Emory University , Atlanta, Georgia
| | - Rickta Mallick
- Division of Nephrology, Department of Medicine, and Department of Physiology, Emory University , Atlanta, Georgia.,Research Service, Atlanta Veterans Affairs Medical Center , Atlanta, Georgia
| | - Abinash C Mistry
- Division of Nephrology, Department of Medicine, and Department of Physiology, Emory University , Atlanta, Georgia.,Research Service, Atlanta Veterans Affairs Medical Center , Atlanta, Georgia
| | - Jennifer L Gooch
- Division of Nephrology, Department of Medicine, and Department of Physiology, Emory University , Atlanta, Georgia.,Research Service, Atlanta Veterans Affairs Medical Center , Atlanta, Georgia
| | - Benjamin Ko
- Department of Medicine, University of Chicago , Chicago, Illinois
| | - Hui Cai
- Division of Nephrology, Department of Medicine, and Department of Physiology, Emory University , Atlanta, Georgia.,Research Service, Atlanta Veterans Affairs Medical Center , Atlanta, Georgia
| | - Robert S Hoover
- Division of Nephrology, Department of Medicine, and Department of Physiology, Emory University , Atlanta, Georgia.,Research Service, Atlanta Veterans Affairs Medical Center , Atlanta, Georgia
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21
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Capdevila JH, Falck JR. The arachidonic acid monooxygenase: from biochemical curiosity to physiological/pathophysiological significance. J Lipid Res 2018; 59:2047-2062. [PMID: 30154230 PMCID: PMC6210905 DOI: 10.1194/jlr.r087882] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/10/2018] [Indexed: 12/19/2022] Open
Abstract
The initial studies of the metabolism of arachidonic acid (AA) by the cytochrome P450 (P450) hemeproteins sought to: a) elucidate the roles for these enzymes in the metabolism of endogenous pools of the FA, b) identify the P450 isoforms involved in AA epoxidation and ω/ω-1 hydroxylation, and c) explore the biological activities of their metabolites. These early investigations provided a foundation for subsequent efforts to establish the physiological relevance of the AA monooxygenase and its contributions to the pathophysiology of, for example, cancer, diabetes, hypertension, inflammation, nociception, and vascular disease. This retrospective analyzes the history of some of these efforts, with emphasis on genetic studies that identified roles for the murine Cyp4a and Cyp2c genes in renal and vascular physiology and the pathophysiology of hypertension and cancer. Wide-ranging investigations by laboratories worldwide, including the authors, have established a better appreciation of the enzymology, genetics, and physiologic roles for what is now known as the third branch of the AA cascade. Combined with the development of analytical and pharmacological tools, including robust synthetic agonists and antagonists of the major metabolites, we stand at the threshold of novel therapeutic approaches for the treatment of renal injury, pain, hypertension, and heart disease.
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Affiliation(s)
- Jorge H Capdevila
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232
| | - John R Falck
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390
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22
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van Megen WH, Grimm PR, Welling PA, van der Wijst J. Renal sodium and magnesium reabsorption are not coupled in a mouse model of Gordon syndrome. Physiol Rep 2018; 6:e13728. [PMID: 30030908 PMCID: PMC6054696 DOI: 10.14814/phy2.13728] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 05/07/2018] [Accepted: 05/10/2018] [Indexed: 12/28/2022] Open
Abstract
Active reabsorption of magnesium (Mg2+ ) in the distal convoluted tubule (DCT) of the kidney is crucial for maintaining Mg2+ homeostasis. Impaired activity of the Na+ -Cl- -cotransporter (NCC) has been associated with hypermagnesiuria and hypomagnesemia, while increased activity of NCC, as observed in patients with Gordon syndrome, is not associated with alterations in Mg2+ balance. To further elucidate the possible interrelationship between NCC activity and renal Mg2+ handling, plasma Mg2+ levels and urinary excretion of sodium (Na+ ) and Mg2+ were measured in a mouse model of Gordon syndrome. In this model, DCT1-specific expression of a constitutively active mutant form of the NCC-phosphorylating kinase, SPAK (CA-SPAK), increases NCC activity and hydrochlorothiazide (HCTZ)-sensitive Na+ reabsorption. These mice were normomagnesemic and HCTZ administration comparably reduced plasma Mg2+ levels in CA-SPAK mice and control littermates. As inferred by the initial response to HCTZ, CA-SPAK mice exhibited greater NCC-dependent Na+ reabsorption together with decreased Mg2+ reabsorption, compared to controls. Following prolonged HCTZ administration (4 days), CA-SPAK mice exhibited higher urinary Mg2+ excretion, while urinary Na+ excretion decreased to levels observed in control animals. Surprisingly, CA-SPAK mice had unaltered renal expression of Trpm6, encoding the Mg2+ -permeable channel TRPM6, or other magnesiotropic genes. In conclusion, CA-SPAK mice exhibit normomagnesemia, despite increased NCC activity and Na+ reabsorption. Thus, Mg2+ reabsorption is not coupled to increased thiazide-sensitive Na+ reabsorption, suggesting a similar process explains normomagnesemia in Gordon syndrome. Further research is required to unravel the molecular underpinnings of this phenomenon and the more pronounced Mg2+ excretion after prolonged HCTZ administration.
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Affiliation(s)
- Wouter H. van Megen
- Department of PhysiologyMaryland Kidney Discovery CenterUniversity of Maryland Medical SchoolBaltimoreMaryland
- Department of PhysiologyRadboud Institute for Molecular Life SciencesRadboud university medical centerNijmegenThe Netherlands
| | - Paul R. Grimm
- Department of PhysiologyMaryland Kidney Discovery CenterUniversity of Maryland Medical SchoolBaltimoreMaryland
| | - Paul A. Welling
- Department of PhysiologyMaryland Kidney Discovery CenterUniversity of Maryland Medical SchoolBaltimoreMaryland
| | - Jenny van der Wijst
- Department of PhysiologyRadboud Institute for Molecular Life SciencesRadboud university medical centerNijmegenThe Netherlands
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23
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Koumangoye R, Omer S, Delpire E. Mistargeting of a truncated Na-K-2Cl cotransporter in epithelial cells. Am J Physiol Cell Physiol 2018; 315:C258-C276. [PMID: 29719172 DOI: 10.1152/ajpcell.00130.2018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We recently reported the case of a young patient with multisystem failure carrying a de novo mutation in SLC12A2, the gene encoding the Na-K-2Cl cotransporter-1 (NKCC1). Heterologous expression studies in nonepithelial cells failed to demonstrate dominant-negative effects. In this study, we examined expression of the mutant cotransporter in epithelial cells. Using Madin-Darby canine kidney (MDCK) cells grown on glass coverslips, permeabilized support, and Matrigel, we show that the fluorescently tagged mutant cotransporter is expressed in cytoplasm and at the apical membrane and affects epithelium integrity. Expression of the mutant transporter at the apical membrane also results in the mislocalization of some of the wild-type transporter to the apical membrane. This mistargeting is specific to NKCC1 as the Na+-K+-ATPase remains localized on the basolateral membrane. To assess transporter localization in vivo, we created a mouse model using CRISPR/cas9 that reproduces the 11 bp deletion in exon 22 of Slc12a2. Although the mice do not display an overt phenotype, we show that the colon and salivary gland expresses wild-type NKCC1 abundantly at the apical pole, confirming the data obtained in cultured epithelial cells. Enough cotransporter must remain, however, on the basolateral membrane to participate in saliva secretion, as no significant decrease in saliva production was observed in the mutant mice.
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Affiliation(s)
- Rainelli Koumangoye
- Department of Anesthesiology, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Salma Omer
- Department of Anesthesiology, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine , Nashville, Tennessee
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24
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Altered Prostasin (CAP1/Prss8) Expression Favors Inflammation and Tissue Remodeling in DSS-induced Colitis. Inflamm Bowel Dis 2016; 22:2824-2839. [PMID: 27755216 DOI: 10.1097/mib.0000000000000940] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND Inflammatory bowel diseases (IBD) including ulcerative colitis and Crohn's disease are diseases with impaired epithelial barrier function. We aimed to investigate whether mutated prostasin and thus, reduced colonic epithelial sodium channel activity predisposes to develop an experimentally dextran sodium sulfate (DSS)-induced colitis. METHODS Wildtype, heterozygous (fr/+), and homozygous (fr/fr) prostasin-mutant rats were treated 7 days with DSS followed by 7 days of recovery and analyzed with respect to histology, clinicopathological parameters, inflammatory marker mRNA transcript expression, and sodium transporter protein expression. RESULTS In this study, a more detailed analysis on rat fr/fr colons revealed reduced numbers of crypt and goblet cells, and local angiodysplasia, as compared with heterozygous (fr/+) and wildtype littermates. Following 2% DSS treatment for 7 days followed by 7 days recovery, fr/fr animals lost body weight, and reached maximal diarrhea score and highest disease activity after only 3 days, and strongly increased cytokine levels. The histology score significantly increased in all groups, but fr/fr colons further displayed pronounced histological alterations with near absence of goblet cells, rearrangement of the lamina propria, and presence of neutrophils, eosinophils, and macrophages. Additionally, fr/fr colons showed ulcerations and edemas that were absent in fr/+ and wildtype littermates. Following recovery, fr/fr rats reached, although significantly delayed, near-normal diarrhea score and disease activity, but exhibited severe architectural remodeling, despite unchanged sodium transporter protein expression. CONCLUSIONS In summary, our results demonstrate a protective role of colonic prostasin expression against experimental colitis, and thus represent a susceptibility gene in the development of inflammatory bowel disease.
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25
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Shepard BD, Cheval L, Peterlin Z, Firestein S, Koepsell H, Doucet A, Pluznick JL. A Renal Olfactory Receptor Aids in Kidney Glucose Handling. Sci Rep 2016; 6:35215. [PMID: 27739476 PMCID: PMC5064317 DOI: 10.1038/srep35215] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 09/22/2016] [Indexed: 12/27/2022] Open
Abstract
Olfactory receptors (ORs) are G protein-coupled receptors which serve important sensory functions beyond their role as odorant detectors in the olfactory epithelium. Here we describe a novel role for one of these ORs, Olfr1393, as a regulator of renal glucose handling. Olfr1393 is specifically expressed in the kidney proximal tubule, which is the site of renal glucose reabsorption. Olfr1393 knockout mice exhibit urinary glucose wasting and improved glucose tolerance, despite euglycemia and normal insulin levels. Consistent with this phenotype, Olfr1393 knockout mice have a significant decrease in luminal expression of Sglt1, a key renal glucose transporter, uncovering a novel regulatory pathway involving Olfr1393 and Sglt1. In addition, by utilizing a large scale screen of over 1400 chemicals we reveal the ligand profile of Olfr1393 for the first time, offering new insight into potential pathways of physiological regulation for this novel signaling pathway.
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Affiliation(s)
- Blythe D. Shepard
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Lydie Cheval
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, CNRS, ERL 8228, Centre de Recherche des Cordeliers, Paris, France
| | - Zita Peterlin
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Stuart Firestein
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Hermann Koepsell
- Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University Wurzburg, Julius-von-Sachs-Platz 2, 97082 Wurzburg, Germany
| | - Alain Doucet
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, CNRS, ERL 8228, Centre de Recherche des Cordeliers, Paris, France
| | - Jennifer L. Pluznick
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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26
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Layton AT, Laghmani K, Vallon V, Edwards A. Solute transport and oxygen consumption along the nephrons: effects of Na+ transport inhibitors. Am J Physiol Renal Physiol 2016; 311:F1217-F1229. [PMID: 27707706 DOI: 10.1152/ajprenal.00294.2016] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 09/28/2016] [Indexed: 01/11/2023] Open
Abstract
Sodium and its associated anions are the major determinant of extracellular fluid volume, and the reabsorption of Na+ by the kidney plays a crucial role in long-term blood pressure control. The goal of this study was to investigate the extent to which inhibitors of transepithelial Na+ transport (TNa) along the nephron alter urinary solute excretion and TNa efficiency and how those effects may vary along different nephron segments. To accomplish that goal, we used the multinephron model developed in the companion study (28). That model represents detailed transcellular and paracellular transport processes along the nephrons of a rat kidney. We simulated the inhibition of the Na+/H+ exchanger (NHE3), the bumetanide-sensitive Na+-K+-2Cl- transporter (NKCC2), the Na+-Cl- cotransporter (NCC), and the amiloride-sensitive Na+ channel (ENaC). Under baseline conditions, NHE3, NKCC2, NCC, and ENaC reabsorb 36, 22, 4, and 7%, respectively, of filtered Na+ The model predicted that inhibition of NHE3 substantially reduced proximal tubule TNa and oxygen consumption (QO2 ). Whole-kidney TNa efficiency, as reflected by the number of moles of Na+ reabsorbed per moles of O2 consumed (denoted by the ratio TNa/QO2 ), decreased by ∼20% with 80% inhibition of NHE3. NKCC2 inhibition simulations predicted a substantial reduction in thick ascending limb TNa and QO2 ; however, the effect on whole-kidney TNa/QO2 was minor. Tubular K+ transport was also substantially impaired, resulting in elevated urinary K+ excretion. The most notable effect of NCC inhibition was to increase the excretion of Na+, K+, and Cl-; its impact on whole-kidney TNa and its efficiency was minor. Inhibition of ENaC was predicted to have opposite effects on the excretion of Na+ (increased) and K+ (decreased) and to have only a minor impact on whole-kidney TNa and TNa/QO2 Overall, model predictions agree well with measured changes in Na+ and K+ excretion in response to diuretics and Na+ transporter mutations.
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Affiliation(s)
- Anita T Layton
- Department of Mathematics, Duke University, Durham, North Carolina;
| | - Kamel Laghmani
- Sorbonne Universités, UPMC Univ Paris 06, Université Paris Descartes, Sorbonne Paris Cité, INSERM UMRS 1138, CNRS ERL 8228, Centre de Recherche des Cordeliers, Paris, France; and
| | - Volker Vallon
- Departments of Medicine and Pharmacology, University of California San Diego, La Jolla, California, and San Diego Veterans Affairs Healthcare System, San Diego, California
| | - Aurélie Edwards
- Sorbonne Universités, UPMC Univ Paris 06, Université Paris Descartes, Sorbonne Paris Cité, INSERM UMRS 1138, CNRS ERL 8228, Centre de Recherche des Cordeliers, Paris, France; and
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27
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Boscardin E, Alijevic O, Hummler E, Frateschi S, Kellenberger S. The function and regulation of acid-sensing ion channels (ASICs) and the epithelial Na(+) channel (ENaC): IUPHAR Review 19. Br J Pharmacol 2016; 173:2671-701. [PMID: 27278329 DOI: 10.1111/bph.13533] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 05/19/2016] [Accepted: 06/02/2016] [Indexed: 12/30/2022] Open
Abstract
Acid-sensing ion channels (ASICs) and the epithelial Na(+) channel (ENaC) are both members of the ENaC/degenerin family of amiloride-sensitive Na(+) channels. ASICs act as proton sensors in the nervous system where they contribute, besides other roles, to fear behaviour, learning and pain sensation. ENaC mediates Na(+) reabsorption across epithelia of the distal kidney and colon and of the airways. ENaC is a clinically used drug target in the context of hypertension and cystic fibrosis, while ASIC is an interesting potential target. Following a brief introduction, here we will review selected aspects of ASIC and ENaC function. We discuss the origin and nature of pH changes in the brain and the involvement of ASICs in synaptic signalling. We expose how in the peripheral nervous system, ASICs cover together with other ion channels a wide pH range as proton sensors. We introduce the mechanisms of aldosterone-dependent ENaC regulation and the evidence for an aldosterone-independent control of ENaC activity, such as regulation by dietary K(+) . We then provide an overview of the regulation of ENaC by proteases, a topic of increasing interest over the past few years. In spite of the profound differences in the physiological and pathological roles of ASICs and ENaC, these channels share many basic functional and structural properties. It is likely that further research will identify physiological contexts in which ASICs and ENaC have similar or overlapping roles.
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Affiliation(s)
- Emilie Boscardin
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Omar Alijevic
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Edith Hummler
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
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28
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Bazúa-Valenti S, Castañeda-Bueno M, Gamba G. Physiological role of SLC12 family members in the kidney. Am J Physiol Renal Physiol 2016; 311:F131-44. [DOI: 10.1152/ajprenal.00071.2016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 04/12/2016] [Indexed: 12/30/2022] Open
Abstract
The solute carrier family 12, as numbered according to Human Genome Organisation (HUGO) nomenclature, encodes the electroneutral cation-coupled chloride cotransporters that are expressed in many cells and tissues; they play key roles in important physiological events, such as cell volume regulation, modulation of the intracellular chloride concentration, and transepithelial ion transport. Most of these family members are expressed in specific regions of the nephron. The Na-K-2Cl cotransporter NKCC2, which is located in the thick ascending limb, and the Na-Cl cotransporter, which is located in the distal convoluted tubule, play important roles in salt reabsorption and serve as the receptors for loop and thiazide diuretics, respectively (Thiazide diuretics are among the most commonly prescribed drugs in the world.). The activity of these transporters correlates with blood pressure levels; thus, their regulation has been a subject of intense research for more than a decade. The K-Cl cotransporters KCC1, KCC3, and KCC4 are expressed in several nephron segments, and their role in renal physiology is less understood but nevertheless important. Evidence suggests that they are involved in modulating proximal tubule glucose reabsorption, thick ascending limb salt reabsorption and collecting duct proton secretion. In this work, we present an overview of the physiological roles of these transporters in the kidney, with particular emphasis on the knowledge gained in the past few years.
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Affiliation(s)
- Silvana Bazúa-Valenti
- Molecular Physiology Unit, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, Mexico City, Mexico
| | - María Castañeda-Bueno
- Molecular Physiology Unit, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, Mexico City, Mexico
| | - Gerardo Gamba
- Molecular Physiology Unit, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, Mexico City, Mexico
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29
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Norlander AE, Saleh MA, Kamat NV, Ko B, Gnecco J, Zhu L, Dale BL, Iwakura Y, Hoover RS, McDonough AA, Madhur MS. Interleukin-17A Regulates Renal Sodium Transporters and Renal Injury in Angiotensin II-Induced Hypertension. Hypertension 2016; 68:167-74. [PMID: 27141060 DOI: 10.1161/hypertensionaha.116.07493] [Citation(s) in RCA: 145] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 04/01/2016] [Indexed: 01/11/2023]
Abstract
Angiotensin II-induced hypertension is associated with an increase in T-cell production of interleukin-17A (IL-17A). Recently, we reported that IL-17A(-/-) mice exhibit blunted hypertension, preserved natriuresis in response to a saline challenge, and decreased renal sodium hydrogen exchanger 3 expression after 2 weeks of angiotensin II infusion compared with wild-type mice. In the current study, we performed renal transporter profiling in mice deficient in IL-17A or the related isoform, IL-17F, after 4 weeks of Ang II infusion, the time when the blood pressure reduction in IL-17A(-/-) mice is most prominent. Deficiency of IL-17A abolished the activation of distal tubule transporters, specifically the sodium-chloride cotransporter and the epithelial sodium channel and protected mice from glomerular and tubular injury. In human proximal tubule (HK-2) cells, IL-17A increased sodium hydrogen exchanger 3 expression through a serum and glucocorticoid-regulated kinase 1-dependent pathway. In mouse distal convoluted tubule cells, IL-17A increased sodium-chloride cotransporter activity in a serum and glucocorticoid-regulated kinase 1/Nedd4-2-dependent pathway. In both cell types, acute treatment with IL-17A induced phosphorylation of serum and glucocorticoid-regulated kinase 1 at serine 78, and treatment with a serum and glucocorticoid-regulated kinase 1 inhibitor blocked the effects of IL-17A on sodium hydrogen exchanger 3 and sodium-chloride cotransporter. Interestingly, both HK-2 and mouse distal convoluted tubule 15 cells produce endogenous IL-17A. IL17F had little or no effect on blood pressure or renal sodium transporter abundance. These studies provide a mechanistic link by which IL-17A modulates renal sodium transport and suggest that IL-17A inhibition may improve renal function in hypertension and other autoimmune disorders.
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Affiliation(s)
- Allison E Norlander
- From the Departments of Molecular Physiology and Biophysics (A.E.N., B.L.D., M.S.M.) and Microbiology, Immunology, and Pathology (J.G.), Vanderbilt University, Nashville, TN; Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN (M.A.S., L.Z., M.S.M.); Faculty of Pharmacy, Department of Pharmacology and Toxicology, Mansoura University, Mansoura, Egypt (M.A.S.); Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles (N.V.K., A.A.M.D.); Department of Medicine, Chicago University School of Medicine, IL (B.K.); Research Institute for Biomedical Sciences, Tokyo University of Science, Tokyo, Japan (Y.I.); and Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA (R.S.H.)
| | - Mohamed A Saleh
- From the Departments of Molecular Physiology and Biophysics (A.E.N., B.L.D., M.S.M.) and Microbiology, Immunology, and Pathology (J.G.), Vanderbilt University, Nashville, TN; Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN (M.A.S., L.Z., M.S.M.); Faculty of Pharmacy, Department of Pharmacology and Toxicology, Mansoura University, Mansoura, Egypt (M.A.S.); Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles (N.V.K., A.A.M.D.); Department of Medicine, Chicago University School of Medicine, IL (B.K.); Research Institute for Biomedical Sciences, Tokyo University of Science, Tokyo, Japan (Y.I.); and Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA (R.S.H.)
| | - Nikhil V Kamat
- From the Departments of Molecular Physiology and Biophysics (A.E.N., B.L.D., M.S.M.) and Microbiology, Immunology, and Pathology (J.G.), Vanderbilt University, Nashville, TN; Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN (M.A.S., L.Z., M.S.M.); Faculty of Pharmacy, Department of Pharmacology and Toxicology, Mansoura University, Mansoura, Egypt (M.A.S.); Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles (N.V.K., A.A.M.D.); Department of Medicine, Chicago University School of Medicine, IL (B.K.); Research Institute for Biomedical Sciences, Tokyo University of Science, Tokyo, Japan (Y.I.); and Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA (R.S.H.)
| | - Benjamin Ko
- From the Departments of Molecular Physiology and Biophysics (A.E.N., B.L.D., M.S.M.) and Microbiology, Immunology, and Pathology (J.G.), Vanderbilt University, Nashville, TN; Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN (M.A.S., L.Z., M.S.M.); Faculty of Pharmacy, Department of Pharmacology and Toxicology, Mansoura University, Mansoura, Egypt (M.A.S.); Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles (N.V.K., A.A.M.D.); Department of Medicine, Chicago University School of Medicine, IL (B.K.); Research Institute for Biomedical Sciences, Tokyo University of Science, Tokyo, Japan (Y.I.); and Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA (R.S.H.)
| | - Juan Gnecco
- From the Departments of Molecular Physiology and Biophysics (A.E.N., B.L.D., M.S.M.) and Microbiology, Immunology, and Pathology (J.G.), Vanderbilt University, Nashville, TN; Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN (M.A.S., L.Z., M.S.M.); Faculty of Pharmacy, Department of Pharmacology and Toxicology, Mansoura University, Mansoura, Egypt (M.A.S.); Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles (N.V.K., A.A.M.D.); Department of Medicine, Chicago University School of Medicine, IL (B.K.); Research Institute for Biomedical Sciences, Tokyo University of Science, Tokyo, Japan (Y.I.); and Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA (R.S.H.)
| | - Linjue Zhu
- From the Departments of Molecular Physiology and Biophysics (A.E.N., B.L.D., M.S.M.) and Microbiology, Immunology, and Pathology (J.G.), Vanderbilt University, Nashville, TN; Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN (M.A.S., L.Z., M.S.M.); Faculty of Pharmacy, Department of Pharmacology and Toxicology, Mansoura University, Mansoura, Egypt (M.A.S.); Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles (N.V.K., A.A.M.D.); Department of Medicine, Chicago University School of Medicine, IL (B.K.); Research Institute for Biomedical Sciences, Tokyo University of Science, Tokyo, Japan (Y.I.); and Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA (R.S.H.)
| | - Bethany L Dale
- From the Departments of Molecular Physiology and Biophysics (A.E.N., B.L.D., M.S.M.) and Microbiology, Immunology, and Pathology (J.G.), Vanderbilt University, Nashville, TN; Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN (M.A.S., L.Z., M.S.M.); Faculty of Pharmacy, Department of Pharmacology and Toxicology, Mansoura University, Mansoura, Egypt (M.A.S.); Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles (N.V.K., A.A.M.D.); Department of Medicine, Chicago University School of Medicine, IL (B.K.); Research Institute for Biomedical Sciences, Tokyo University of Science, Tokyo, Japan (Y.I.); and Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA (R.S.H.)
| | - Yoichiro Iwakura
- From the Departments of Molecular Physiology and Biophysics (A.E.N., B.L.D., M.S.M.) and Microbiology, Immunology, and Pathology (J.G.), Vanderbilt University, Nashville, TN; Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN (M.A.S., L.Z., M.S.M.); Faculty of Pharmacy, Department of Pharmacology and Toxicology, Mansoura University, Mansoura, Egypt (M.A.S.); Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles (N.V.K., A.A.M.D.); Department of Medicine, Chicago University School of Medicine, IL (B.K.); Research Institute for Biomedical Sciences, Tokyo University of Science, Tokyo, Japan (Y.I.); and Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA (R.S.H.)
| | - Robert S Hoover
- From the Departments of Molecular Physiology and Biophysics (A.E.N., B.L.D., M.S.M.) and Microbiology, Immunology, and Pathology (J.G.), Vanderbilt University, Nashville, TN; Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN (M.A.S., L.Z., M.S.M.); Faculty of Pharmacy, Department of Pharmacology and Toxicology, Mansoura University, Mansoura, Egypt (M.A.S.); Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles (N.V.K., A.A.M.D.); Department of Medicine, Chicago University School of Medicine, IL (B.K.); Research Institute for Biomedical Sciences, Tokyo University of Science, Tokyo, Japan (Y.I.); and Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA (R.S.H.)
| | - Alicia A McDonough
- From the Departments of Molecular Physiology and Biophysics (A.E.N., B.L.D., M.S.M.) and Microbiology, Immunology, and Pathology (J.G.), Vanderbilt University, Nashville, TN; Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN (M.A.S., L.Z., M.S.M.); Faculty of Pharmacy, Department of Pharmacology and Toxicology, Mansoura University, Mansoura, Egypt (M.A.S.); Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles (N.V.K., A.A.M.D.); Department of Medicine, Chicago University School of Medicine, IL (B.K.); Research Institute for Biomedical Sciences, Tokyo University of Science, Tokyo, Japan (Y.I.); and Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA (R.S.H.)
| | - Meena S Madhur
- From the Departments of Molecular Physiology and Biophysics (A.E.N., B.L.D., M.S.M.) and Microbiology, Immunology, and Pathology (J.G.), Vanderbilt University, Nashville, TN; Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN (M.A.S., L.Z., M.S.M.); Faculty of Pharmacy, Department of Pharmacology and Toxicology, Mansoura University, Mansoura, Egypt (M.A.S.); Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles (N.V.K., A.A.M.D.); Department of Medicine, Chicago University School of Medicine, IL (B.K.); Research Institute for Biomedical Sciences, Tokyo University of Science, Tokyo, Japan (Y.I.); and Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA (R.S.H.)
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Using genetic mouse models to gain insight into glaucoma: Past results and future possibilities. Exp Eye Res 2015; 141:42-56. [PMID: 26116903 DOI: 10.1016/j.exer.2015.06.019] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 06/16/2015] [Accepted: 06/23/2015] [Indexed: 12/18/2022]
Abstract
While all forms of glaucoma are characterized by a specific pattern of retinal ganglion cell death, they are clinically divided into several distinct subclasses, including normal tension glaucoma, primary open angle glaucoma, congenital glaucoma, and secondary glaucoma. For each type of glaucoma there are likely numerous molecular pathways that control susceptibility to the disease. Given this complexity, a single animal model will never precisely model all aspects of all the different types of human glaucoma. Therefore, multiple animal models have been utilized to study glaucoma but more are needed. Because of the powerful genetic tools available to use in the laboratory mouse, it has proven to be a highly useful mammalian system for studying the pathophysiology of human disease. The similarity between human and mouse eyes coupled with the ability to use a combination of advanced cell biological and genetic tools in mice have led to a large increase in the number of studies using mice to model specific glaucoma phenotypes. Over the last decade, numerous new mouse models and genetic tools have emerged, providing important insight into the cell biology and genetics of glaucoma. In this review, we describe available mouse genetic models that can be used to study glaucoma-relevant disease/pathobiology. Furthermore, we discuss how these models have been used to gain insights into ocular hypertension (a major risk factor for glaucoma) and glaucomatous retinal ganglion cell death. Finally, the potential for developing new mouse models and using advanced genetic tools and resources for studying glaucoma are discussed.
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