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Ray EC, Nickerson A, Sheng S, Carrisoza-Gaytán R, Lam T, Marciszyn A, Zhang L, Jordahl A, Bi C, Winfrey A, Kou Z, Gingras S, Kirabo A, Satlin LM, Kleyman TR. Influence of Proteolytic Cleavage of ENaC's Gamma Subunit upon Na + and K + Handling. Am J Physiol Renal Physiol 2024. [PMID: 38634134 DOI: 10.1152/ajprenal.00027.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 04/09/2024] [Indexed: 04/19/2024] Open
Abstract
The ENaC γ subunit is essential for homeostasis of Na+, K+, and body fluid. Dual γ subunit cleavage before and after a short inhibitory tract allows dissociation of this tract, increasing channel open probability (PO), in vitro. Cleavage proximal to the tract occurs at a furin recognition sequence (143RKRR146, in the mouse γ subunit). Loss of furin-mediated cleavage prevents in vitro activation of the channel by proteolysis at distal sites. We hypothesized that 143RKRR146 mutation to 143QQQQ146 (γQ4) in 129/Sv mice would reduce ENaC PO, impair flow-stimulated flux of Na+ (JNa) and K+ (JK) in perfused collecting ducts, reduce colonic amiloride-sensitive short circuit current (ISC), and impair Na+, K+, and body fluid homeostasis. Immunoblot of γQ4/Q4 mouse kidney lysates confirmed loss of a band consistent in size with the furin-cleaved proteolytic fragment. However, γQ4/Q4 male mice on a low Na+ diet did not exhibit altered ENaC PO or flow-induced JNa, though flow-induced JK modestly decreased. Colonic amiloride-sensitive ISC in γQ4/Q4 mice was not altered. γQ4/Q4 males, but not females, exhibited mildly impaired fluid volume conservation when challenged with a low Na+ diet. Blood Na+ and K+ were unchanged on a regular, low Na+, or high K+ diet. These findings suggest that biochemical evidence of γ subunit cleavage should be used in isolation to evaluate ENaC activity. Further, factors independent of γ subunit cleavage modulate channel PO and the influence of ENaC on Na+, K+, and fluid volume homeostasis in 129/Sv mice, in vivo.
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Affiliation(s)
- Evan C Ray
- Internal Medicine - Renal-Electrolyte, University of Pittsburgh, Pittsburgh, PA, United States
| | - Andrew Nickerson
- Department of Medicine, University of Pittsburgh, Pittsburgh, United States
| | - Shaohu Sheng
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | | | - Tracey Lam
- Internal Medicine - Renal-Electrolyte, University of Pittsburgh, Pittsburgh, PA, United States
| | - Allison Marciszyn
- Medicine, Renal-Electrolyte Division, University of Pittsburgh, United States
| | - Lei Zhang
- Internal Medicine - Renal-Electrolyte Division, University of Pittsburgh, Pittsburgh, PA, United States
| | - Alexa Jordahl
- Internal Medicine - Renal-Electrolyte, University of Pittsburgh, Pittsburgh, Select, United States
| | - Chunming Bi
- Immunology, University of Pittsburgh, United States
| | - Aaliyah Winfrey
- Department of Medicine Renal-Electrolyte Division, University of Pittsburgh, Pittsburgh, PA, United States
| | - Zhaohui Kou
- Department of Immunology, University of Pittsburgh, United States
| | | | - Annet Kirabo
- Departments of Medicine and of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Lisa M Satlin
- Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York, United States
| | - Thomas R Kleyman
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
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Ray EC, Nickerson A, Sheng S, Carrisoza-Gaytan R, Lam T, Marciszyn A, Zhang L, Jordahl A, Bi C, Winfrey A, Kou Z, Gingras S, Kirabo A, Satlin LM, Kleyman TR. Proteolytic Cleavage of the ENaC γ Subunit - Impact Upon Na + and K + Handling. bioRxiv 2024:2024.02.12.579964. [PMID: 38405735 PMCID: PMC10888851 DOI: 10.1101/2024.02.12.579964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
The ENaC gamma subunit is essential for homeostasis of Na + , K + , and body fluid. Dual subunit cleavage before and after a short inhibitory tract allows dissociation of this tract, increasing channel open probability (P O ), in vitro . Cleavage proximal to the tract occurs at a furin recognition sequence ( 143 RKRR 146 in mouse). Loss of furin-mediated cleavage prevents in vitro activation of the channel by proteolysis at distal sites. We hypothesized that 143 RKRR 146 mutation to 143 QQQQ 146 ( Q4 ) in 129/Sv mice would reduce ENaC P O , impair flow-stimulated flux of Na + (J Na ) and K + (J K ) in perfused collecting ducts, reduce colonic amiloride-sensitive short circuit current (I SC ), and impair Na + , K + , and body fluid homeostasis. Immunoblot of Q4/Q4 mouse kidney lysates confirmed loss of a band consistent in size with the furin-cleaved proteolytic fragment. However, Q4/Q4 male mice on a low Na + diet did not exhibit altered ENaC P O or flow-induced J Na , though flow-induced J K modestly decreased. Colonic amiloride-sensitive I SC in Q4/Q4 mice was not altered. Q4/Q4 males, but not females, exhibited mildly impaired fluid volume conservation when challenged with a low Na + diet. Blood Na + and K + were unchanged on a regular, low Na + , or high K + diet. These findings suggest that biochemical evidence of gamma subunit cleavage should not be used in isolation to evaluate ENaC activity. Further, factors independent of gamma subunit cleavage modulate channel P O and the influence of ENaC on Na + , K + , and fluid volume homeostasis in 129/Sv mice, in vivo .
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Mutchler SM, Whelan SCM, Marciszyn A, Chen J, Kleyman TR, Shi S. Role of paraoxonase 3 in regulating ENaC-mediated Na + transport in the distal nephron. J Physiol 2024; 602:737-757. [PMID: 38345534 PMCID: PMC10940207 DOI: 10.1113/jp285034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 01/11/2024] [Indexed: 02/18/2024] Open
Abstract
Paraoxonase 3 (PON3) is expressed in the aldosterone-sensitive distal nephron, where filtered Na+ is reabsorbed mainly via the epithelial Na+ channel (ENaC) and Na+ -coupled co-transporters. We previously showed that PON3 negatively regulates ENaC through a chaperone mechanism. The present study aimed to determine the physiological role of PON3 in renal Na+ and K+ homeostasis. Pon3 knockout (KO) mice had higher amiloride-induced natriuresis and lower plasma [K+ ] at baseline. Single channel recordings in split-open tubules showed that the number of active channels per patch was significantly higher in KO mice, resulting in a higher channel activity in the absence of PON3. Although whole kidney abundance of ENaC subunits was not altered in Pon3 KOs, ENaC gamma subunit was more apically distributed within the connecting tubules and cortical collecting ducts of Pon3 KO kidneys. Additionally, small interfering RNA-mediated knockdown of PON3 in cultured mouse cortical collecting duct cells led to an increased surface abundance of ENaC gamma subunit. As a result of lower plasma [K+ ], sodium chloride co-transporter phosphorylation was enhanced in the KO kidneys, a phenotype that was corrected by a high K+ diet. Finally, PON3 expression was upregulated in mouse kidneys under dietary K+ restriction, potentially providing a mechanism to dampen ENaC activity and associated K+ secretion. Taken together, our results show that PON3 has a role in renal Na+ and K+ homeostasis through regulating ENaC functional expression in the distal nephron. KEY POINTS: Paraoxonase 3 (PON3) is expressed in the distal nephron of mouse kidneys and functions as a molecular chaperone to reduce epithelial Na+ channel (ENaC) expression and activity in heterologous expression systems. We examined the physiological role of PON3 in renal Na+ and K+ handling using a Pon3 knockout (KO) mouse model. At baseline, Pon3 KO mice had lower blood [K+ ], more functional ENaC in connecting tubules/cortical collecting ducts, higher amiloride-induced natriuresis, and enhanced sodium chloride co-transporter (NCC) phosphorylation. Upon challenge with a high K+ diet, Pon3 KO mice had normalized blood [K+ ] and -NCC phosphorylation but lower circulating aldosterone levels compared to their littermate controls. Kidney PON3 abundance was altered in mice under dietary K+ loading or K+ restriction, providing a potential mechanism for regulating ENaC functional expression and renal Na+ and K+ homeostasis in the distal nephron.
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Affiliation(s)
| | | | - Allison Marciszyn
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jingxin Chen
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Thomas R. Kleyman
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Shujie Shi
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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Porter A, Vorndran HE, Marciszyn A, Mutchler SM, Subramanya AR, Kleyman TR, Hendershot LM, Brodsky JL, Buck TM. Excess dietary sodium partially restores salt and water homeostasis caused by loss of the endoplasmic reticulum molecular chaperone, GRP170, in the mouse nephron. bioRxiv 2024:2024.01.13.575426. [PMID: 38260467 PMCID: PMC10802592 DOI: 10.1101/2024.01.13.575426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The maintenance of fluid and electrolyte homeostasis by the kidney requires proper folding and trafficking of ion channels and transporters in kidney epithelia. Each of these processes requires a specific subset of a diverse class of proteins termed molecular chaperones. One such chaperone is GRP170, which is an Hsp70-like, endoplasmic reticulum (ER)-localized chaperone that plays roles in protein quality control and protein folding in the ER. We previously determined that loss of GRP170 in the mouse nephron leads to hypovolemia, electrolyte imbalance, and rapid weight loss. In addition, GRP170-deficient mice develop an AKI-like phenotype, typified by tubular injury, elevation of clinical kidney injury markers, and induction of the unfolded protein response (UPR). By using an inducible GRP170 knockout cellular model, we confirmed that GRP170 depletion induces the UPR, triggers an apoptotic response, and disrupts protein homeostasis. Based on these data, we hypothesized that UPR induction underlies hyponatremia and volume depletion in rodents, but that these and other phenotypes might be rectified by supplementation with high salt. To test this hypothesis, control and GRP170 tubule-specific knockout mice were provided with a diet containing 8% sodium chloride. We discovered that sodium supplementation improved electrolyte imbalance and reduced clinical kidney injury markers, but was unable to restore weight or tubule integrity. These results are consistent with UPR induction contributing to the kidney injury phenotype in the nephron-specific GR170 knockout model, and that the role of GRP170 in kidney epithelia is essential to both maintain electrolyte balance and cellular protein homeostasis.
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Affiliation(s)
- Aidan Porter
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA
- Division of Pediatric Nephrology, University of Pittsburgh, Pittsburgh, PA
| | - Hannah E. Vorndran
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA
| | - Allison Marciszyn
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, PA
| | - Stephanie M. Mutchler
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, PA
| | - Arohan R. Subramanya
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, PA
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA
| | - Thomas R. Kleyman
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, PA
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA
| | - Linda M. Hendershot
- Department of Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, TN 30105
| | - Jeffrey L. Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA
| | - Teresa M. Buck
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA
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Al-Bataineh MM, Kinlough CL, Marciszyn A, Lam T, Ye L, Kidd K, Maggiore JC, Poland PA, Kmoch S, Bleyer A, Bain DJ, Montalbetti N, Kleyman TR, Hughey RP, Ray EC. Influence of glycoprotein MUC1 on trafficking of the Ca 2+-selective ion channels, TRPV5 and TRPV6, and on in vivo calcium homeostasis. J Biol Chem 2023; 299:102925. [PMID: 36682497 PMCID: PMC9996365 DOI: 10.1016/j.jbc.2023.102925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 01/09/2023] [Accepted: 01/12/2023] [Indexed: 01/22/2023] Open
Abstract
Polymorphism of the gene encoding mucin 1 (MUC1) is associated with skeletal and dental phenotypes in human genomic studies. Animals lacking MUC1 exhibit mild reduction in bone density. These phenotypes could be a consequence of modulation of bodily Ca homeostasis by MUC1, as suggested by the previous observation that MUC1 enhances cell surface expression of the Ca2+-selective channel, TRPV5, in cultured unpolarized cells. Using biotinylation of cell surface proteins, we asked whether MUC1 influences endocytosis of TRPV5 and another Ca2+-selective TRP channel, TRPV6, in cultured polarized epithelial cells. Our results indicate that MUC1 reduces endocytosis of both channels, enhancing cell surface expression. Further, we found that mice lacking MUC1 lose apical localization of TRPV5 and TRPV6 in the renal tubular and duodenal epithelium. Females, but not males, lacking MUC1 exhibit reduced blood Ca2+. However, mice lacking MUC1 exhibited no differences in basal urinary Ca excretion or Ca retention in response to PTH receptor signaling, suggesting compensation by transport mechanisms independent of TRPV5 and TRPV6. Finally, humans with autosomal dominant tubulointerstitial kidney disease due to frame-shift mutation of MUC1 (ADTKD-MUC1) exhibit reduced plasma Ca concentrations compared to control individuals with mutations in the gene encoding uromodulin (ADTKD-UMOD), consistent with MUC1 haploinsufficiency causing reduced bodily Ca2+. In summary, our results provide further insight into the role of MUC1 in Ca2+-selective TRP channel endocytosis and the overall effects on Ca concentrations.
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Affiliation(s)
- Mohammad M Al-Bataineh
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Carol L Kinlough
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Allison Marciszyn
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Tracey Lam
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Lorena Ye
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Kendrah Kidd
- Section on Nephrology, Department of Medicine, Wake Forest University, Winston-Salem, North Carolina, USA; Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Joseph C Maggiore
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Paul A Poland
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Stanislav Kmoch
- Section on Nephrology, Department of Medicine, Wake Forest University, Winston-Salem, North Carolina, USA; Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Anthony Bleyer
- Section on Nephrology, Department of Medicine, Wake Forest University, Winston-Salem, North Carolina, USA; Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Daniel J Bain
- Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Nicolas Montalbetti
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Thomas R Kleyman
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Rebecca P Hughey
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
| | - Evan C Ray
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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6
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Ray EC, Pitzer A, Lam T, Jordahl A, Patel R, Ao M, Marciszyn A, Winfrey A, Barak Y, Sheng S, Kirabo A, Kleyman TR. Salt sensitivity of volume and blood pressure in a mouse with globally reduced ENaC γ-subunit expression. Am J Physiol Renal Physiol 2021; 321:F705-F714. [PMID: 34632813 PMCID: PMC8714976 DOI: 10.1152/ajprenal.00559.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 09/14/2021] [Accepted: 10/04/2021] [Indexed: 12/15/2022] Open
Abstract
The epithelial Na+ channel (ENaC) promotes the absorption of Na+ in the aldosterone-sensitive distal nephron, colon, and respiratory epithelia. Deletion of genes encoding subunits of ENaC results in early postnatal mortality. Here, we present the initial characterization of a mouse with dramatically suppressed expression of the ENaC γ-subunit. We used this hypomorphic (γmt) allele to explore the importance of this subunit in homeostasis of electrolytes and body fluid volume. At baseline, γ-subunit expression in γmt/mt mice was markedly suppressed in the kidney and lung, whereas electrolytes resembled those of littermate controls. Aldosterone levels in γmt/mt mice exceeded those seen in littermate controls. Quantitative magnetic resonance measurement of body composition revealed similar baseline body water, lean tissue mass, and fat tissue mass in γmt/mt mice and controls. γmt/mt mice exhibited a more rapid decline in body water and lean tissue mass in response to a low-Na+ diet than the controls. Replacement of drinking water with 2% saline selectively and transiently increased body water and lean tissue mass in γmt/mt mice relative to the controls. Lower blood pressures were variably observed in γmt/mt mice on a high-salt diet compared with the controls. γmt/mt also exhibited reduced diurnal blood pressure variation, a "nondipping" phenotype, on a high-Na+ diet. Although ENaC in the renal tubules and colon works to prevent extracellular fluid volume depletion, our observations suggest that ENaC in other tissues may participate in regulating extracellular fluid volume and blood pressure.NEW & NOTEWORTHY A mouse with globally suppressed expression of the epithelial Na+ channel γ-subunit showed enhanced sensitivity to dietary salt, including a transient increase in total body fluid, reduced blood pressure, and reduced diurnal blood pressure variation when given a dietary NaCl challenge. These results point to a role for the epithelial Na+ channel in regulating body fluid and blood pressure beyond classical transepithelial Na+ transport mechanisms.
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Affiliation(s)
- Evan C Ray
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Ashley Pitzer
- Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Tracey Lam
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Alexa Jordahl
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Ritam Patel
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Mingfang Ao
- Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Allison Marciszyn
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Aaliyah Winfrey
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Yaacov Barak
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh, Magee-Womens Research Institute, Pittsburgh, Pennsylvania
| | - Shaohu Sheng
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Annet Kirabo
- Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Thomas R Kleyman
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
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Boyd‐Shiwarski C, Weaver C, Nkashama L, Connolly K, Shiwarski D, Mutchler S, Marciszyn A, Subramanya A. The Effects of Dietary Potassium on Mouse Blood Pressure and Ion Transport. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.751.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Claire Weaver
- Renal Electrolyte DivisionUniversity of PittsburghPittsburghPA
| | - Lubika Nkashama
- Renal Electrolyte DivisionUniversity of PittsburghPittsburghPA
| | - Kelly Connolly
- Renal Electrolyte DivisionUniversity of PittsburghPittsburghPA
| | - Dan Shiwarski
- Biomedical EngineeringCarnegie Mellon UniversityPittsburghPA
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8
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Nkashama LJ, Roy A, Carrisoza‐Gaytan R, Ray EC, Marciszyn A, Kleyman TR, Satlin LM, Subramanya AR. The Nedd8 Co‐E3 DCNL4 is regulated by dietary potassium in renal intercalated cells and promotes WNK kinase degradation via the KLHL3/CUL3 complex. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.747.8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Ankita Roy
- MedicineUniversity of PittsburghPittsburghPA
| | | | - Evan C. Ray
- MedicineUniversity of PittsburghPittsburghPA
| | | | | | - Lisa M. Satlin
- PediatricsIcahn School of Medicine at Mount SinaiNew YorkNY
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Boyd-Shiwarski CR, Shiwarski DJ, Roy A, Namboodiri HN, Nkashama LJ, Xie J, McClain KL, Marciszyn A, Kleyman TR, Tan RJ, Stolz DB, Puthenveedu MA, Huang CL, Subramanya AR. Potassium-regulated distal tubule WNK bodies are kidney-specific WNK1 dependent. Mol Biol Cell 2017; 29:499-509. [PMID: 29237822 PMCID: PMC6014176 DOI: 10.1091/mbc.e17-08-0529] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 11/27/2017] [Accepted: 12/06/2017] [Indexed: 01/18/2023] Open
Abstract
WNK bodies are large punctate membraneless cytosolic signaling foci that sequester WNK serine–threonine kinases and form in renal distal tubular epithelial cells during shifts in total body potassium balance. The assembly of these structures requires KS-WNK1, a truncated isoform of the WNK1 gene that is exclusively expressed in the distal tubule. With-no-lysine (WNK) kinases coordinate volume and potassium homeostasis by regulating renal tubular electrolyte transport. In the distal convoluted tubule (DCT), potassium imbalance causes WNK signaling complexes to concentrate into large discrete foci, which we call “WNK bodies.” Although these structures have been reported previously, the mechanisms that drive their assembly remain obscure. Here, we show that kidney-specific WNK1 (KS-WNK1), a truncated kinase-defective WNK1 isoform that is highly expressed in the DCT, is critical for WNK body formation. While morphologically distinct WNK bodies were evident in the distal tubules of mice subjected to dietary potassium loading and restriction, KS-WNK1 knockout mice were deficient in these structures under identical conditions. Combining in vivo observations in kidney with reconstitution studies in cell culture, we found that WNK bodies are dynamic membraneless foci that are distinct from conventional organelles, colocalize with the ribosomal protein L22, and cluster the WNK signaling pathway. The formation of WNK bodies requires an evolutionarily conserved cysteine-rich hydrophobic motif harbored within a unique N-terminal exon of KS-WNK1. We propose that WNK bodies are not pathological aggregates, but rather are KS-WNK1–dependent microdomains of the DCT cytosol that modulate WNK signaling during physiological shifts in potassium balance.
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Affiliation(s)
- Cary R Boyd-Shiwarski
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Daniel J Shiwarski
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Ankita Roy
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Hima N Namboodiri
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Lubika J Nkashama
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Jian Xie
- Department of Internal Medicine, Division of Nephrology, University of Iowa Carver College of Medicine, Iowa City, IA 52242
| | - Kara L McClain
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Allison Marciszyn
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Thomas R Kleyman
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261.,Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Roderick J Tan
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Donna B Stolz
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | | | - Chou-Long Huang
- Department of Internal Medicine, Division of Nephrology, University of Iowa Carver College of Medicine, Iowa City, IA 52242
| | - Arohan R Subramanya
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261 .,Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261.,VA Pittsburgh Healthcare System, Pittsburgh, PA 15240
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10
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Emlet DR, Pastor-Soler N, Marciszyn A, Wen X, Gomez H, Humphries WH, Morrisroe S, Volpe JK, Kellum JA. Insulin-like growth factor binding protein 7 and tissue inhibitor of metalloproteinases-2: differential expression and secretion in human kidney tubule cells. Am J Physiol Renal Physiol 2016; 312:F284-F296. [PMID: 28003188 DOI: 10.1152/ajprenal.00271.2016] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 11/11/2016] [Accepted: 11/28/2016] [Indexed: 01/04/2023] Open
Abstract
We have characterized the expression and secretion of the acute kidney injury (AKI) biomarkers insulin-like growth factor binding protein 7 (IGFBP7) and tissue inhibitor of metalloproteinases-2 (TIMP-2) in human kidney epithelial cells in primary cell culture and tissue. We established cell culture model systems of primary kidney cells of proximal and distal tubule origin and observed that both proteins are indeed expressed and secreted in both tubule cell types in vitro. However, TIMP-2 is both expressed and secreted preferentially by cells of distal tubule origin, while IGFBP7 is equally expressed across tubule cell types yet preferentially secreted by cells of proximal tubule origin. In human kidney tissue, strong staining of IGFBP7 was seen in the luminal brush-border region of a subset of proximal tubule cells, and TIMP-2 stained intracellularly in distal tubules. Additionally, while some tubular colocalization of both biomarkers was identified with the injury markers kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin, both biomarkers could also be seen alone, suggesting the possibility for differential mechanistic and/or temporal profiles of regulation of these early AKI biomarkers from known markers of injury. Last, an in vitro model of ischemia-reperfusion demonstrated enhancement of secretion of both markers early after reperfusion. This work provides a rationale for further investigation of these markers for their potential role in the pathogenesis of acute kidney injury.
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Affiliation(s)
- David R Emlet
- Center for Critical Care Nephrology, Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Nuria Pastor-Soler
- Renal Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; and
| | - Allison Marciszyn
- Renal Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; and
| | - Xiaoyan Wen
- Center for Critical Care Nephrology, Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Hernando Gomez
- Center for Critical Care Nephrology, Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | | | - Seth Morrisroe
- Center for Critical Care Nephrology, Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Jacob K Volpe
- Center for Critical Care Nephrology, Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - John A Kellum
- Center for Critical Care Nephrology, Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; .,Renal Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; and
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11
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Al‐bataineh M, Li H, Marciszyn A, Bhalla V, Hallows K, Pastor‐Soler N. AMPK Regulates the Vacuolar H
+
‐ATPase via 14‐3‐3 Proteins. FASEB J 2015. [DOI: 10.1096/fasebj.29.1_supplement.969.23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Hui Li
- Renal‐Electrolyte Division U. of PittsburghPittsburghPAUnited States
| | - Allison Marciszyn
- Renal‐Electrolyte Division U. of PittsburghPittsburghPAUnited States
| | - Vivek Bhalla
- Division of NephrologyStanford UniversityPalo AltoCAUnited States
| | - Kenneth Hallows
- Renal‐Electrolyte Division U. of PittsburghPittsburghPAUnited States
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12
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Affiliation(s)
- Mohammad Al‐bataineh
- Medicine, Renal‐Electrolyte Division U. of PIttsburgh School of MedicinePIttsburghPAUnited States
| | - Fan Gong
- Medicine, Renal‐Electrolyte Division U. of PIttsburgh School of MedicinePIttsburghPAUnited States
| | - Hui Li
- Medicine, Renal‐Electrolyte Division U. of PIttsburgh School of MedicinePIttsburghPAUnited States
| | - Allison Marciszyn
- Medicine, Renal‐Electrolyte Division U. of PIttsburgh School of MedicinePIttsburghPAUnited States
| | - Vivek Bhalla
- Medicine, Division of Nephrology Stanford University School of MedicineStanfordCAUnited States
| | - Kenneth Hallows
- Medicine, Renal‐Electrolyte Division U. of PIttsburgh School of MedicinePIttsburghPAUnited States
| | - Núria Pastor‐Soler
- Medicine, Renal‐Electrolyte Division U. of PIttsburgh School of MedicinePIttsburghPAUnited States
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13
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Weixel KM, Marciszyn A, Alzamora R, Li H, Fischer O, Edinger RS, Hallows KR, Johnson JP. Resveratrol inhibits the epithelial sodium channel via phopshoinositides and AMP-activated protein kinase in kidney collecting duct cells. PLoS One 2013; 8:e78019. [PMID: 24205069 PMCID: PMC3812018 DOI: 10.1371/journal.pone.0078019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 09/16/2013] [Indexed: 11/25/2022] Open
Abstract
Resveratrol, a naturally occurring phytoalexin, has reported cardioprotective, anti-inflammatory, chemopreventative and antidiabetic properties. Several studies indicate the multiple effects of resveratrol on cellular function are due to its inhibition of class 1A phosphoinositide 3-kinase (PI3K) mediated signaling pathways, but it also activates AMP-activated protein kinase (AMPK). As sodium transport in the kidney via the Epithelial Sodium Channel (ENaC) is highly sensitive to changes in phosphoinositide signaling in the membrane and AMPK, we employed resveratrol to probe the relative effects of phosphatidylinositol species in the plasma membrane and AMPK activity and their impact on ENaC activity in mouse cortical collecting duct (mpkCCDc14) cells. Here we demonstrate that resveratrol acutely reduces amiloride-sensitive current in mpkCCDc14 cells. The time course and dose dependency of this inhibition paralleled depletion of the PI(3,4,5)P3 reporter (AKT-PH) in live-cell microscopy, indicating the early inhibition is likely mediated by resveratrol's known effects on PI3K activity. Additionally, resveratrol induces a late inhibitory effect (4–24 hours) that appears to be mediated via AMPK activation. Resveratrol treatment induces significant AMPK activation compared with vehicle controls after 4 h, which persists through 16 h. Knockdown of AMPK or treatment with the AMPK inhibitor Compound C reduced the late phase of current reduction but had no effect on the early inhibitory activity of resveratrol. Collectively, these data demonstrate that resveratrol inhibits ENaC activity by a dual effect: an early reduction in activity seen within 5 minutes related to depletion of membrane PIP3, and a sustained late (4–24 h) effect secondary to activation of AMPK.
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Affiliation(s)
- Kelly M. Weixel
- Biology Department, Washington and Jefferson University, Washington, Pennsylvania, United States of America
- * E-mail:
| | - Allison Marciszyn
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Rodrigo Alzamora
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Hui Li
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Oliver Fischer
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Robert S. Edinger
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Kenneth R. Hallows
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - John P. Johnson
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
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