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Ray A, Stelloh C, Liu Y, Meyer A, Geurts AM, Cowley AW, Greene AS, Liang M, Rao S. Histone Modifications and Their Contributions to Hypertension. Hypertension 2024; 81:229-239. [PMID: 38031837 PMCID: PMC11229175 DOI: 10.1161/hypertensionaha.123.21755] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
Essential hypertension, a multifaceted disorder, is a worldwide health problem. A complex network of genetic, epigenetic, physiological, and environmental components regulates blood pressure (BP), and any dysregulation of this network may result in hypertension. Growing evidence suggests a role for epigenetic factors in BP regulation. Any alterations in the expression or functions of these epigenetic regulators may dysregulate various determinants of BP, thereby promoting the development of hypertension. Histone posttranslational modifications are critical epigenetic regulators that have been implicated in hypertension. Several studies have demonstrated a clear association between the increased expression of some histone-modifying enzymes, especially HDACs (histone deacetylases), and hypertension. In addition, treatment with HDAC inhibitors lowers BP in hypertensive animal models, providing an excellent opportunity to design new drugs to treat hypertension. In this review, we discuss the potential contribution of different histone modifications to the regulation of BP.
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Affiliation(s)
- Atrayee Ray
- Versiti Blood Research Institute, Milwaukee, WI (A.R., C.S., A.M., S.R.)
- Department of Physiology, Center of Systems Molecular Medicine (A.R., A.M.G., A.C.), Medical College of Wisconsin, Milwaukee
| | - Cary Stelloh
- Versiti Blood Research Institute, Milwaukee, WI (A.R., C.S., A.M., S.R.)
| | - Yong Liu
- Department of Physiology, The University of Arizona, Tucson (Y.L., M.L.)
| | - Alison Meyer
- Versiti Blood Research Institute, Milwaukee, WI (A.R., C.S., A.M., S.R.)
| | - Aron M Geurts
- Department of Physiology, Center of Systems Molecular Medicine (A.R., A.M.G., A.C.), Medical College of Wisconsin, Milwaukee
| | - Allen W Cowley
- Department of Physiology, Center of Systems Molecular Medicine (A.R., A.M.G., A.C.), Medical College of Wisconsin, Milwaukee
| | | | - Mingyu Liang
- Department of Physiology, The University of Arizona, Tucson (Y.L., M.L.)
| | - Sridhar Rao
- Versiti Blood Research Institute, Milwaukee, WI (A.R., C.S., A.M., S.R.)
- Department of Pediatrics, Section of Hematology/Oncology/Transplantation (S.R.), Medical College of Wisconsin, Milwaukee
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Tsilosani A, Gao C, Zhang W. Aldosterone-Regulated Sodium Transport and Blood Pressure. Front Physiol 2022; 13:770375. [PMID: 35197862 PMCID: PMC8859437 DOI: 10.3389/fphys.2022.770375] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 01/06/2022] [Indexed: 11/13/2022] Open
Abstract
Aldosterone is a major mineralocorticoid steroid hormone secreted by glomerulosa cells in the adrenal cortex. It regulates a variety of physiological responses including those to oxidative stress, inflammation, fluid disruption, and abnormal blood pressure through its actions on various tissues including the kidney, heart, and the central nervous system. Aldosterone synthesis is primarily regulated by angiotensin II, K+ concentration, and adrenocorticotrophic hormone. Elevated serum aldosterone levels increase blood pressure largely by increasing Na+ re-absorption in the kidney through regulating transcription and activity of the epithelial sodium channel (ENaC). This review focuses on the signaling pathways involved in aldosterone synthesis and its effects on Na+ reabsorption through ENaC.
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Affiliation(s)
- Akaki Tsilosani
- Department of Regenerative & Cancer Cell Biology, Albany Medical College, Albany, NY, United States
| | - Chao Gao
- Department of Regenerative & Cancer Cell Biology, Albany Medical College, Albany, NY, United States
| | - Wenzheng Zhang
- Department of Regenerative & Cancer Cell Biology, Albany Medical College, Albany, NY, United States
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Eadon MT, Lampe S, Baig MM, Collins KS, Melo Ferreira R, Mang H, Cheng YH, Barwinska D, El-Achkar TM, Schwantes-An TH, Winfree S, Temm CJ, Ferkowicz MJ, Dunn KW, Kelly KJ, Sutton TA, Moe SM, Moorthi RN, Phillips CL, Dagher PC. Clinical, histopathologic and molecular features of idiopathic and diabetic nodular mesangial sclerosis in humans. Nephrol Dial Transplant 2021; 37:72-84. [PMID: 33537765 DOI: 10.1093/ndt/gfaa331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Idiopathic nodular mesangial sclerosis, also called idiopathic nodular glomerulosclerosis (ING), is a rare clinical entity with an unclear pathogenesis. The hallmark of this disease is the presence of nodular mesangial sclerosis on histology without clinical evidence of diabetes mellitus or other predisposing diagnoses. To achieve insights into its pathogenesis, we queried the clinical, histopathologic and transcriptomic features of ING and nodular diabetic nephropathy (DN). METHODS All renal biopsy reports accessioned at Indiana University Health from 2001 to 2016 were reviewed to identify 48 ING cases. Clinical and histopathologic features were compared between individuals with ING and DN (n = 751). Glomeruli of ING (n = 5), DN (n = 18) and reference (REF) nephrectomy (n = 9) samples were isolated by laser microdissection and RNA was sequenced. Immunohistochemistry of proline-rich 36 (PRR36) protein was performed. RESULTS ING subjects were frequently hypertensive (95.8%) with a smoking history (66.7%). ING subjects were older, had lower proteinuria and had less hyaline arteriolosclerosis than DN subjects. Butanoate metabolism was an enriched pathway in ING samples compared with either REF or DN samples. The top differentially expressed gene, PRR36, had increased expression in glomeruli 248-fold [false discovery rate (FDR) P = 5.93 × 10-6] compared with the REF and increased 109-fold (FDR P = 1.85 × 10-6) compared with DN samples. Immunohistochemistry revealed a reduced proportion of cells with perinuclear reaction in ING samples as compared to DN. CONCLUSIONS Despite similar clinical and histopathologic characteristics in ING and DN, the uncovered transcriptomic signature suggests that ING has distinct molecular features from nodular DN. Further study is warranted to understand these relationships.
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Affiliation(s)
- Michael T Eadon
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Sam Lampe
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Mirza M Baig
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Kimberly S Collins
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Ricardo Melo Ferreira
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Henry Mang
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Ying-Hua Cheng
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Daria Barwinska
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Tarek M El-Achkar
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Tae-Hwi Schwantes-An
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Seth Winfree
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.,Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Constance J Temm
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Michael J Ferkowicz
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Kenneth W Dunn
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Katherine J Kelly
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Timothy A Sutton
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Sharon M Moe
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Ranjani N Moorthi
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Carrie L Phillips
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Pierre C Dagher
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
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Basu S, Nandy A, Biswas D. Keeping RNA polymerase II on the run: Functions of MLL fusion partners in transcriptional regulation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194563. [PMID: 32348849 DOI: 10.1016/j.bbagrm.2020.194563] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/13/2020] [Accepted: 04/13/2020] [Indexed: 12/21/2022]
Abstract
Since the identification of key MLL fusion partners as transcription elongation factors regulating expression of HOX cluster genes during hematopoiesis, extensive work from the last decade has resulted in significant progress in our overall mechanistic understanding of role of MLL fusion partner proteins in transcriptional regulation of diverse set of genes beyond just the HOX cluster. In this review, we are going to detail overall understanding of role of MLL fusion partner proteins in transcriptional regulation and thus provide mechanistic insights into possible MLL fusion protein-mediated transcriptional misregulation leading to aberrant hematopoiesis and leukemogenesis.
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Affiliation(s)
- Subham Basu
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 32, India
| | - Arijit Nandy
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Debabrata Biswas
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 32, India.
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Zhang L, Chen L, Gao C, Chen E, Lightle AR, Foulke L, Zhao B, Higgins PJ, Zhang W. Loss of Histone H3 K79 Methyltransferase Dot1l Facilitates Kidney Fibrosis by Upregulating Endothelin 1 through Histone Deacetylase 2. J Am Soc Nephrol 2019; 31:337-349. [PMID: 31843983 DOI: 10.1681/asn.2019070739] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 11/01/2019] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The progression rate of CKD varies substantially among patients. The genetic and epigenetic contributions that modify how individual patients respond to kidney injury are largely unknown. Emerging evidence has suggested that histone H3 K79 methyltransferase Dot1l has an antifibrotic effect by repressing Edn1, which encodes endothelin 1 in the connecting tubule/collecting duct. METHODS To determine if deletion of the Dot1l gene is a genetic and epigenetic risk factor through regulating Edn1, we studied four groups of mice: wild-type mice, connecting tubule/collecting duct-specific Dot1l conditional knockout mice (Dot1lAC ), Dot1l and Edn1 double-knockout mice (DEAC ), and Edn1 connecting tubule/collecting duct-specific conditional knockout mice (Edn1AC ), under three experimental conditions (streptozotocin-induced diabetes, during normal aging, and after unilateral ureteral obstruction). We used several approaches (colocalization, glutathione S-transferase pulldown, coimmunoprecipitation, yeast two-hybrid, gel shift, and chromatin immunoprecipitation assays) to identify and confirm interaction of Dot1a (the major Dot1l splicing variant in the mouse kidney) with histone deacetylase 2 (HDAC2), as well as the function of the Dot1a-HDAC2 complex in regulating Edn1 transcription. RESULTS In each case, Dot1lAC mice developed more pronounced kidney fibrosis and kidney malfunction compared with wild-type mice. These Dot1lAC phenotypes were ameliorated in the double-knockout DEAC mice. The interaction between Dot1a and HDAC2 prevents the Dot1a-HDAC2 complex from association with DNA, providing a counterbalancing mechanism governing Edn1 transcription by modulating H3 K79 dimethylation and H3 acetylation at the Edn1 promoter. CONCLUSIONS Our study confirms Dot1l to be a genetic and epigenetic modifier of kidney fibrosis, reveals a new mechanism regulating Edn1 transcription by Dot1a and HDAC2, and reinforces endothelin 1 as a therapeutic target of kidney fibrosis.
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Affiliation(s)
- Long Zhang
- Departments of Regenerative and Cancer Cell Biology and
| | - Lihe Chen
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, Bethesda, Maryland; and
| | - Chao Gao
- Departments of Regenerative and Cancer Cell Biology and
| | - Enuo Chen
- Departments of Regenerative and Cancer Cell Biology and
| | - Andrea R Lightle
- Pathology and Laboratory Medicine, Albany Medical College, Albany, New York
| | - Llewellyn Foulke
- Pathology and Laboratory Medicine, Albany Medical College, Albany, New York
| | - Bihong Zhao
- Department of Pathology and Laboratory Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
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Affiliation(s)
- Mingyu Liang
- From the Center of Systems Molecular Medicine, Department of Physiology, Medical College of Wisconsin, Milwaukee
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Chen L, Gao C, Zhang L, Zhang Y, Chen E, Zhang W. Highly tamoxifen-inducible principal cell-specific Cre mice with complete fidelity in cell specificity and no leakiness. Am J Physiol Renal Physiol 2018; 314:F572-F583. [PMID: 29357435 PMCID: PMC5966762 DOI: 10.1152/ajprenal.00436.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 12/11/2017] [Accepted: 12/13/2017] [Indexed: 11/22/2022] Open
Abstract
An ideal inducible system should be cell specific and have absolutely no background recombination without induction (i.e., no leakiness), a high recombination rate after induction, and complete fidelity in cell specificity (i.e., restricted recombination exclusively in cells where the driver gene is expressed). However, such an ideal mouse model remains unavailable for collecting duct research. Here, we report a mouse model that meets these criteria. In this model, a cassette expressing ERT2CreERT2 ( ECE) is inserted at the ATG of the endogenous Aqp2 locus to disrupt Aqp2 function and to express ECE under the control of the Aqp2 promoter. The resulting allele is named Aqp2ECE. There was no indication of a significant impact of disruption of a copy of Aqp2 on renal function and blood pressure control in adult Aqp2ECE/+ heterozygotes. Without tamoxifen, Aqp2ECE did not activate a Cre-dependent red fluorescence protein (RFP) reporter in adult kidneys. A single injection of tamoxifen (2 mg) to adult mice enabled Aqp2ECE to induce robust RFP expression in the whole kidney 24 h postinjection, with the highest recombination efficiency of 95% in the inner medulla. All RFP-labeled cells expressed principal cell markers (Aqp2 and Aqp3), but not intercalated cell markers (V-ATPase B1B2, and carbonic anhydrase II). Hence, Aqp2ECE confers principal cell-specific tamoxifen-inducible recombination with absolutely no leakiness, high inducibility, and complete fidelity in cell specificity, which should be an important tool for temporospatial control of target genes in the principal cells and for Aqp2+ lineage tracing in adult mice.
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Affiliation(s)
- Lihe Chen
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute , Bethesda, Maryland
| | - Chao Gao
- Department of Regenerative and Cancer Cell Biology, Albany Medical College , Albany, New York
| | - Long Zhang
- Department of Regenerative and Cancer Cell Biology, Albany Medical College , Albany, New York
| | - Ye Zhang
- Department of Regenerative and Cancer Cell Biology, Albany Medical College , Albany, New York
| | - Enuo Chen
- Department of Regenerative and Cancer Cell Biology, Albany Medical College , Albany, New York
| | - Wenzheng Zhang
- Department of Regenerative and Cancer Cell Biology, Albany Medical College , Albany, New York
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Tomati V, Pesce E, Caci E, Sondo E, Scudieri P, Marini M, Amato F, Castaldo G, Ravazzolo R, Galietta LJV, Pedemonte N. High-throughput screening identifies FAU protein as a regulator of mutant cystic fibrosis transmembrane conductance regulator channel. J Biol Chem 2018; 293:1203-1217. [PMID: 29158263 PMCID: PMC5787799 DOI: 10.1074/jbc.m117.816595] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 10/19/2017] [Indexed: 01/01/2023] Open
Abstract
In cystic fibrosis, deletion of phenylalanine 508 (F508del) in the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel causes misfolding and premature degradation. One possible approach to reducing the detrimental health effects of cystic fibrosis could be the identification of proteins whose suppression rescues F508del-CFTR function in bronchial epithelial cells. However, searches for these potential targets have not yet been conducted, particularly in a relevant airway background using a functional readout. To identify proteins associated with F508del-CFTR processing, we used a high-throughput functional assay to screen an siRNA library targeting 6,650 different cellular proteins. We identified 37 proteins whose silencing significantly rescued F508del-CFTR activity, as indicated by enhanced anion transport through the plasma membrane. These proteins included FAU, UBE2I, UBA52, MLLT6, UBA2, CHD4, PLXNA1, and TRIM24, among others. We focused our attention on FAU, a poorly characterized protein with unknown function. FAU knockdown increased the plasma membrane targeting and function of F508del-CFTR, but not of wild-type CFTR. Investigation into the mechanism of action revealed a preferential physical interaction of FAU with mutant CFTR, leading to its degradation. FAU and other proteins identified in our screening may offer a therapeutically relevant panel of drug targets to correct basic defects in F508del-CFTR processing.
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Affiliation(s)
- Valeria Tomati
- From the Unità Operativa Complessa (U.O.C.) Genetica Medica, Istituto Giannina Gaslini, 16147 Genova, Italy
| | - Emanuela Pesce
- From the Unità Operativa Complessa (U.O.C.) Genetica Medica, Istituto Giannina Gaslini, 16147 Genova, Italy
| | - Emanuela Caci
- From the Unità Operativa Complessa (U.O.C.) Genetica Medica, Istituto Giannina Gaslini, 16147 Genova, Italy
| | - Elvira Sondo
- From the Unità Operativa Complessa (U.O.C.) Genetica Medica, Istituto Giannina Gaslini, 16147 Genova, Italy
| | - Paolo Scudieri
- the Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | - Monica Marini
- From the Unità Operativa Complessa (U.O.C.) Genetica Medica, Istituto Giannina Gaslini, 16147 Genova, Italy
| | - Felice Amato
- the Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, 80138 Naples, Italy
- CEINGE-Advanced Biotechnology Scarl, 80145 Naples, Italy, and
| | - Giuseppe Castaldo
- the Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, 80138 Naples, Italy
- CEINGE-Advanced Biotechnology Scarl, 80145 Naples, Italy, and
| | - Roberto Ravazzolo
- From the Unità Operativa Complessa (U.O.C.) Genetica Medica, Istituto Giannina Gaslini, 16147 Genova, Italy
- the Dipartimento di Neuroscienze, Riabilitazione, Oftalmologia, Genetica e Scienze Materno-Infantili (DINOGMI), University of Genova, 16132 Genova, Italy
| | - Luis J V Galietta
- the Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | - Nicoletta Pedemonte
- From the Unità Operativa Complessa (U.O.C.) Genetica Medica, Istituto Giannina Gaslini, 16147 Genova, Italy,
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Srikan P, Callen B, Phillips K, Tavakoli A, Brockett R, Hanucharurnkul S, Beebe L. Testing a Model of Sodium Reduction in Hypertensive Older Thai Adults. J Nutr Gerontol Geriatr 2017; 36:48-62. [PMID: 28107108 DOI: 10.1080/21551197.2016.1274278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Hypertensive older adults will benefit if there is a clear understanding of the factors related to sodium reduction. That would raise awareness of the causes, consequently reducing many health risks, lowering health care costs, and diminishing economic and social burden from high blood pressure. This study explored predictors of urinary sodium excretion. A cross-sectional, correlational study was conducted in 312 hypertensive older Thai adults. Questionnaires related to knowledge, self-care agency, self-care behavior of sodium reduction, and 24-hour urinary sodium analyses were used, followed by the application of structural equation modeling and the Analysis of Moment Structures program. Self-care agency, knowledge, self-care behavior, rural/urban location, and education accounted for 61% of urinary sodium excretion. Self-care agency, knowledge, and self-care behavior were the main predictors in the urinary sodium excretion model. This study suggests establishing supportive educative sodium reduction-related programs that improve knowledge and enhance self-care agency, as well as a comparison of the changes of sodium reduction self-care behavior and urinary sodium excretion over time after the intervention.
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Affiliation(s)
| | - Bonnie Callen
- b College of Nursing , University of Tennessee , Knoxville , Tennessee , USA
| | - Kenneth Phillips
- b College of Nursing , University of Tennessee , Knoxville , Tennessee , USA
| | - Abbas Tavakoli
- c College of Nursing , University of South Carolina , Columbia , North Carolina , USA
| | - Ralph Brockett
- d College of Education , University of Tennessee , Knoxville , Tennessee , USA
| | | | - Lora Beebe
- b College of Nursing , University of Tennessee , Knoxville , Tennessee , USA
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Elijovich F, Weinberger MH, Anderson CAM, Appel LJ, Bursztyn M, Cook NR, Dart RA, Newton-Cheh CH, Sacks FM, Laffer CL. Salt Sensitivity of Blood Pressure: A Scientific Statement From the American Heart Association. Hypertension 2016; 68:e7-e46. [PMID: 27443572 DOI: 10.1161/hyp.0000000000000047] [Citation(s) in RCA: 326] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Xiao Z, Chen L, Zhou Q, Zhang W. Dot1l deficiency leads to increased intercalated cells and upregulation of V-ATPase B1 in mice. Exp Cell Res 2015; 344:167-75. [PMID: 26404731 DOI: 10.1016/j.yexcr.2015.09.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 09/16/2015] [Accepted: 09/19/2015] [Indexed: 01/19/2023]
Abstract
The collecting duct in the mammalian kidney consists of principal cells (PCs) and intercalated cells (ICs), which regulate electrolyte/fluid and acid/base balance, respectively. The epigenetic regulators of PC and IC differentiation remain obscure. We previously used Aqp2 and V-ATPase B1B2 to label PCs and ICs, respectively. We found that mice with histone H3 K79 methyltransferase Dot1l disrupted in Aqp2-expressing cells (Dot1l(AC)) vs. Dot1l(f/f) possessed ~20% more ICs coupled with a similar decrease in PCs. Here, we performed multiple double immunofluorescence staining using various PC and IC markers and confirmed that this finding. Both α-IC and β-IC populations were significantly expanded in Dot1l(AC) vs. Dot1l(f/f). These changes are associated with significantly upregulated V-ATPase B1 and B2, but not Aqp2, AE1, and Pendrin. Chromatin immunoprecipitation assay unveiled a significant reduction of Dot1l and H3K79 di-methylation bound at the Atp6v1b1 5' flanking region. Overexpression of Dot1a significantly downregulated a stably-transfected luciferase reporter driven by the Atp6v1b1 promoter in IMCD3 cells. This downregulation was impaired, but not completely abolished when a methyltransferase-dead mutant was overexpressed. Taken together, our data suggest that Dot1l is a new epigenetic regulator of PC and IC differentiation and Atp6v1b1 is a new transcriptional target of Dot1l.
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Affiliation(s)
- Zhou Xiao
- Department of Internal Medicine, Xiangya Hospital, Central South University, Changsha, Hunan 410008, PR China; Department of Internal Medicine, University of Texas Medical School at Houston, Houston, TX 77030, USA
| | - Lihe Chen
- Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Qiaoling Zhou
- Department of Internal Medicine, Xiangya Hospital, Central South University, Changsha, Hunan 410008, PR China
| | - Wenzheng Zhang
- Department of Internal Medicine, University of Texas Medical School at Houston, Houston, TX 77030, USA; Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
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Zhang W. Epigenetics of epithelial Na + channel-dependent sodium uptake and blood pressure regulation. World J Nephrol 2015; 4:363-366. [PMID: 26167459 PMCID: PMC4491926 DOI: 10.5527/wjn.v4.i3.363] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 12/08/2014] [Accepted: 05/18/2015] [Indexed: 02/06/2023] Open
Abstract
The epithelial Na+ channel (ENaC) consists of α, β, γ subunits. Its expression and function are regulated by aldosterone at multiple levels including transcription. ENaC plays a key role in Na+ homeostasis and blood pressure. Mutations in ENaC subunit genes result in hypertension or hypotension, depending on the nature of the mutations. Transcription of αENaC is considered as the rate-limiting step in the formation of functional ENaC. As an aldosterone target gene, αENaC is activated upon aldosterone- mineralocorticoid receptor binding to the cis-elements in the αENaC promoter, which is packed into chromatin. However, how aldosterone alters chromatin structure to induce changes in transcription is poorly understood. Studies by others and us suggest that Dot1a-Af9 complex represses αENaC by directly binding and regulating targeted histone H3 K79 hypermethylation at the specific subregions of αENaC promoter. Aldosterone decreases Dot1a-Af9 formation by impairing expression of Dot1a and Af9 and by inducing Sgk1, which, in turn, phosphorylates Af9 at S435 to weaken Dot1a-Af9 interaction. MR attenuates Dot1a-Af9 effect by competing with Dot1a for binding Af9. Af17 relieves repression by interfering with Dot1a-Af9 interaction and promoting Dot1a nuclear export. Af17-/- mice exhibit defects in ENaC expression, renal Na+ retention, and blood pressure control. This review gives a brief summary of these novel findings.
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Abstract
Aldosterone is a major regulator of Na(+) absorption and acts primarily by controlling the epithelial Na(+) channel (ENaC) function at multiple levels including transcription. ENaC consists of α, β, and γ subunits. In the classical model, aldosterone enhances transcription primarily by activating mineralocorticoid receptor (MR). However, how aldosterone induces chromatin alternation and thus leads to gene activation or repression remains largely unknown. Emerging evidence suggests that Dot1a-Af9 complex plays an important role in repression of αENaC by directly binding and modulating targeted histone H3 K79 hypermethylation at the specific subregions of αENaC promoter. Aldosterone impairs Dot1a-Af9 formation by decreasing expression of Dot1a and Af9 and by inducing Sgk1, which, in turn, phosphorylates Af9 at S435 to weaken Dot1a-Af9 interaction. MR counterbalances Dot1a-Af9 action by competing with Dot1a for binding Af9. Af17 derepresses αENaC by competitively interacting with Dot1a and facilitating Dot1a nuclear export. Consistently, MR(-/-) mice have impaired ENaC expression at day 5 after birth, which may contribute to progressive development of pseudohypoaldosteronism type 1 in a later stage. Af17(-/-) mice have decreased ENaC expression, renal Na(+) retention, and blood pressure. In contrast, Dot1l(AC) mice have increased αENaC expression, despite a 20% reduction of the principal cells. This chapter reviews these findings linking aldosterone action to ENaC transcription through chromatin modification. Future direction toward the understanding the role of Dot1a-Af9 complex beyond ENaC regulation, in particular, in renal fibrosis is also briefly discussed.
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Affiliation(s)
- Lihe Chen
- Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas, USA; Division of Renal Diseases and Hypertension, Department of Internal Medicine, University of Texas Medical School at Houston, Houston, Texas, USA
| | - Xi Zhang
- Division of Renal Diseases and Hypertension, Department of Internal Medicine, University of Texas Medical School at Houston, Houston, Texas, USA
| | - Wenzheng Zhang
- Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas, USA; Division of Renal Diseases and Hypertension, Department of Internal Medicine, University of Texas Medical School at Houston, Houston, Texas, USA.
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14
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Abstract
The apical membrane epithelial Na(+) channel subunit (ENaC) in series with the basolateral Na(+)/K(+)-adenosine triphosphatase mediates collecting duct Na(+) reabsorption. Aldosterone induces αENaC gene transcription, which appears to be rate limiting for ENaC activity in this segment. Although this response has long been assumed to be solely the result of liganded nuclear hormone receptors trans-activating αENaC, epigenetic controls of basal and aldosterone-induced transcription of αENaC in the collecting duct recently were described. These epigenetic pathways involve dynamic nuclear repressor complexes targeted to specific subregions of the αENaC promoter and consisting of the histone methyltransferase disrupter of telomeric silencing (Dot)1a together with the transcriptional factor Af9 or the nicotinamide adenine dinucleotide (NAD)-dependent protein deacetylase Sirt1, key co-regulatory proteins, including serum- and glucocorticoid-induced kinase-1 and the putative transcription factor Af17, and targeted chromatin modifications. The complexes, through the action of Dot1a, maintain chromatin associated with the αENaC promoter in a stable hypermethylated state, constraining αENaC transcription under basal conditions. Aldosterone and serum- and glucocorticoid-induced kinase-1, itself, activate αENaC transcription in large part by disrupting or diminishing the Dot1a-Af9 and Dot1a-Sirt1 complexes and their effects on chromatin. Mouse models indicate potential roles of the Dot1a pathways in renal salt excretion and hypertension.
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Affiliation(s)
- Bruce C Kone
- Division of Renal Diseases and Hypertension, Department of Internal Medicine, The University of Texas Medical School, Houston, TX.
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15
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Berrout J, Mamenko M, Zaika OL, Chen L, Zang W, Pochynyuk O, O'Neil RG. Emerging role of the calcium-activated, small conductance, SK3 K+ channel in distal tubule function: regulation by TRPV4. PLoS One 2014; 9:e95149. [PMID: 24762817 PMCID: PMC3999037 DOI: 10.1371/journal.pone.0095149] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 03/24/2014] [Indexed: 12/24/2022] Open
Abstract
The Ca2+-activated, maxi-K (BK) K+ channel, with low Ca2+-binding affinity, is expressed in the distal tubule of the nephron and contributes to flow-dependent K+ secretion. In the present study we demonstrate that the Ca2+-activated, SK3 (KCa2.3) K+ channel, with high Ca2+-binding affinity, is also expressed in the mouse kidney (RT-PCR, immunoblots). Immunohistochemical evaluations using tubule specific markers demonstrate significant expression of SK3 in the distal tubule and the entire collecting duct system, including the connecting tubule (CNT) and cortical collecting duct (CCD). In CNT and CCD, main sites for K+ secretion, the highest levels of expression were along the apical (luminal) cell membranes, including for both principal cells (PCs) and intercalated cells (ICs), posturing the channel for Ca2+-dependent K+ secretion. Fluorescent assessment of cell membrane potential in native, split-opened CCD, demonstrated that selective activation of the Ca2+-permeable TRPV4 channel, thereby inducing Ca2+ influx and elevating intracellular Ca2+ levels, activated both the SK3 channel and the BK channel leading to hyperpolarization of the cell membrane. The hyperpolarization response was decreased to a similar extent by either inhibition of SK3 channel with the selective SK antagonist, apamin, or by inhibition of the BK channel with the selective antagonist, iberiotoxin (IbTX). Addition of both inhibitors produced a further depolarization, indicating cooperative effects of the two channels on Vm. It is concluded that SK3 is functionally expressed in the distal nephron and collecting ducts where induction of TRPV4-mediated Ca2+ influx, leading to elevated intracellular Ca2+ levels, activates this high Ca2+-affinity K+ channel. Further, with sites of expression localized to the apical cell membrane, especially in the CNT and CCD, SK3 is poised to be a key pathway for Ca2+-dependent regulation of membrane potential and K+ secretion.
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Affiliation(s)
- Jonathan Berrout
- Department of Integrative Biology, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
| | - Mykola Mamenko
- Department of Integrative Biology, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
| | - Oleg L. Zaika
- Department of Integrative Biology, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
| | - Lihe Chen
- Department of Internal Medicine-Division of Renal Diseases and Hypertension, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
| | - Wenzheng Zang
- Department of Internal Medicine-Division of Renal Diseases and Hypertension, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
| | - Oleh Pochynyuk
- Department of Integrative Biology, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
| | - Roger G. O'Neil
- Department of Integrative Biology, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
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16
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Zhang X, Zhou Q, Chen L, Berger S, Wu H, Xiao Z, Pearce D, Zhou X, Zhang W. Mineralocorticoid receptor antagonizes Dot1a-Af9 complex to increase αENaC transcription. Am J Physiol Renal Physiol 2013; 305:F1436-44. [PMID: 24026182 DOI: 10.1152/ajprenal.00202.2013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Aldosterone is a major regulator of Na(+) absorption and acts by activating the mineralocorticoid receptor (MR) to stimulate the epithelial Na(+) channel (ENaC). MR(-/-) mice exhibited pseudohypoaldosteronism type 1 (hyponatremia, hyperkalemia, salt wasting, and high levels of aldosterone) and died around postnatal day 10. However, if and how MR regulates ENaC transcription remain incompletely understood. Our earlier work demonstrated that aldosterone activates αENaC transcription by reducing expression of Dot1a and Af9 and by impairing Dot1a-Af9 interaction. Most recently, we reported identification of a major Af9 binding site in the αENaC promoter and upregulation of αENaC mRNA expression in mouse kidneys lacking Dot1a. Despite these findings, the putative antagonism between the MR/aldosterone and Dot1a-Af9 complexes has never been addressed. The molecular defects leading to PHA-1 in MR(-/-) mice remain elusive. Here, we report that MR competes with Dot1a to bind Af9. MR/aldosterone and Dot1a-Af9 complexes mutually counterbalance ENaC mRNA expression in inner medullary collecting duct 3 (IMCD3) cells. Real-time RT-quantitative PCR revealed that 5-day-old MR(-/-) vs. MR(+/+) mice had significantly lower αENaC mRNA levels. This change was associated with an increased Af9 binding and H3 K79 hypermethylation in the αENaC promoter. Therefore, this study identified MR as a novel binding partner and regulator of Af9 and a novel mechanism coupling MR-mediated activation with relief of Dot1a-Af9-mediated repression via MR-Af9 interaction. Impaired ENaC expression due to failure to inhibit Dot1a-Af9 may play an important role in the early stages of PHA-1 (before postnatal day 8) in MR(-/-) mice.
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Affiliation(s)
- Xi Zhang
- Dept. of Internal Medicine, Univ. of Texas Medical School at Houston, 6431 Fannin, MSB 5.135, Houston, TX 77030.
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17
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Staruschenko A. Aldosterone-dependent trans-activation and epigenetic derepression of ENaC: where is the balance? Am J Physiol Renal Physiol 2013; 305:F968-9. [PMID: 23842778 DOI: 10.1152/ajprenal.00386.2013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Alexander Staruschenko
- Dept. of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226.
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18
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Zhang W, Yu Z, Wu H, Chen L, Kong Q, Kone BC. An Af9 cis-element directly targets Dot1a to mediate transcriptional repression of the αENaC gene. Am J Physiol Renal Physiol 2013; 304:F367-75. [PMID: 23152297 PMCID: PMC3566494 DOI: 10.1152/ajprenal.00537.2011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 11/11/2012] [Indexed: 01/17/2023] Open
Abstract
The epithelial Na(+) channel subunit-α (αENaC) of the distal nephron is essential for salt balance. We previously demonstrated that the histone methyltransferase Dot1a and its protein partner Af9 basally repress αENaC transcription in mouse inner medullary collecting duct type 3 (mIMCD3) cells and link aldosterone-elicited chromatin modifications to αENaC transcriptional activation. Af9 DNA-binding activity has never been demonstrated, and whether and where Af9 binds to the αENaC promoter to target Dot1a are unknown. The present study sought to identify functional Af9 cis-element(s) in the -57/+439 "R3" subregion of αENaC, the principal site for Dot1a-Af9 interaction, in mIMCD3 cells. We also exploited connecting tubule/collecting duct-specific Dot1l-deficient mice (Dot1l(AC)) to determine the impact of Dot1l inactivation on renal αENaC expression in vivo. mIMCD3 cell lines expressing αENaC promoter-reporter constructs harboring deletion of +74/+107 demonstrated greatly reduced association of Af9 and Dot1a by ChIP/qPCR. Aldosterone treatment resulted in further decrements in Af9 and Dot1a association with the αENaC promoter. Gel shift and antibody competition assays using wild-type and mutant oligomers revealed Af9-containing +78/+92 αENaC DNA-protein complexes in nuclear extracts of mIMCD3 cells. Mutation of the +78/+92 element resulted in higher basal αENaC promoter activity and impaired Dot1a-mediated inhibition in trans-repression assays. In agreement, mice with connecting tubule/collecting duct-specific knockout of Dot1l exhibited greater αENaC mRNA levels in kidney compared with control. Thus, we conclude that +78/+92 of αENaC represents the primary Af9 binding site involved in recruiting Dot1a to repress basal and aldosterone-sensitive αENaC transcription and that Dot1l inactivation promotes αENaC mRNA expression by eliminating Dot1a-mediated repression.
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Affiliation(s)
- Wenzheng Zhang
- Division of Renal Diseases and Hypertension, The University of Texas Medical School at Houston, Houston, TX 77030, USA
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19
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Wu H, Chen L, Zhou Q, Zhang X, Berger S, Bi J, Lewis DE, Xia Y, Zhang W. Aqp2-expressing cells give rise to renal intercalated cells. J Am Soc Nephrol 2013; 24:243-52. [PMID: 23308014 DOI: 10.1681/asn.2012080866] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The mammalian collecting duct comprises principal and intercalated cells, which maintain sodium/water and acid/base balance, respectively, but the epigenetic contributors to the differentiation of these cell types remain unknown. Here, we investigated whether the histone H3 K79 methyltransferase Dot1l, which is highly expressed in principal cells, participates in this process. Taking advantage of the distribution of aquaporin 2 (Aqp2), which localizes to principal cells of the collecting duct, we developed mice lacking Dot1l in Aqp2-expressing cells (Dot1l(AC)) and found that these mice had approximately 20% fewer principal cells and 13%-16% more intercalated cells than control mice. This deletion of Dot1l in principal cells abolished histone H3 K79 methylation in these cells, but unexpectedly, most intercalated cells also had undetectable di-methyl K79, suggesting that Aqp2(+) cells give rise to intercalated cells. These Aqp2(+) cell-derived intercalated cells were present in both developing and mature kidneys. Furthermore, compared with control mice, Dot1l(AC) mice had 40% higher urine volume and 18% lower urine osmolarity with relatively normal electrolyte and acid-base homeostasis. In conclusion, these data suggest that Dot1l deletion facilitates the differentiation of some α- and β-intercalated cells from Aqp2-expressing progenitor cells or mature principal cells.
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Affiliation(s)
- Hongyu Wu
- Department of Internal Medicine, The University of Texas Health Science Center at Houston, Houston, Texas, USA
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20
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Wu H, Chen L, Zhang X, Zhou Q, Li JM, Berger S, Borok Z, Zhou B, Xiao Z, Yin H, Liu M, Wang Y, Jin J, Blackburn MR, Xia Y, Zhang W. Aqp5 is a new transcriptional target of Dot1a and a regulator of Aqp2. PLoS One 2013; 8:e53342. [PMID: 23326416 PMCID: PMC3542343 DOI: 10.1371/journal.pone.0053342] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 11/27/2012] [Indexed: 12/02/2022] Open
Abstract
Dot1l encodes histone H3 K79 methyltransferase Dot1a. Mice with Dot1l deficiency in renal Aqp2-expressing cells (Dot1l(AC)) develop polyuria by unknown mechanisms. Here, we report that Aqp5 links Dot1l deletion to polyuria through Aqp2. cDNA array analysis revealed and real-time RT-qPCR validated Aqp5 as the most upregulated gene in Dot1l(AC) vs. control mice. Aqp5 protein is barely detectable in controls, but robustly expressed in the Dot1l(AC) kidneys, where it colocalizes with Aqp2. The upregulation of Aqp5 is coupled with reduced association of Dot1a and H3 dimethyl K79 with specific subregions in Aqp5 5' flanking region in Dot1l(AC) vs. control mice. In vitro studies in IMCD3, MLE-15 and 293Tcells using multiple approaches including real-time RT-qPCR, luciferase reporter assay, cell surface biotinylation assay, colocalization, and co-immunoprecipitation uncovered that Dot1a represses Aqp5. Human AQP5 interacts with AQP2 and impairs its cell surface localization. The AQP5/AQP2 complex partially resides in the ER/Golgi. Consistently, AQP5 is expressed in none of 15 normal controls, but in all of 17 kidney biopsies from patients with diabetic nephropathy. In the patients with diabetic nephropathy, AQP5 colocalizes with AQP2 in the perinuclear region and AQP5 expression is associated with impaired cellular H3 dimethyl K79. Taken together, these data for the first time identify Aqp5 as a Dot1a potential transcriptional target, and an Aqp2 binding partner and regulator, and suggest that the upregulated Aqp5 may contribute to polyuria, possibly by impairing Aqp2 membrane localization, in Dot1l(AC) mice and in patients with diabetic nephropathy.
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Affiliation(s)
- Hongyu Wu
- Department of Internal Medicine, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Lihe Chen
- Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Xi Zhang
- Department of Internal Medicine, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Qiaoling Zhou
- Department of Internal Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ju-Mei Li
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Stefan Berger
- German Cancer Research Center, Division Molecular Biology of the Cell I, Heidelberg, Germany
| | - Zea Borok
- Will Rogers Institute Pulmonary Research Center, Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Beiyun Zhou
- Will Rogers Institute Pulmonary Research Center, Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Zhou Xiao
- Department of Internal Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Hongling Yin
- Department of Internal Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Mingyao Liu
- Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- Institute of Biosciences and Technology and Department of Molecular and Cellular Medicine, Texas A&M University System Health Science Center, Houston, Texas, United States of America
| | - Ying Wang
- Institute of Biosciences and Technology and Department of Molecular and Cellular Medicine, Texas A&M University System Health Science Center, Houston, Texas, United States of America
| | - Jianping Jin
- Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Michael R. Blackburn
- Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Yang Xia
- Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Wenzheng Zhang
- Department of Internal Medicine, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
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21
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Spironolactone rescues Dot1a-Af9-mediated repression of endothelin-1 and improves kidney injury in streptozotocin-induced diabetic rats. PLoS One 2012; 7:e47360. [PMID: 23077601 PMCID: PMC3471839 DOI: 10.1371/journal.pone.0047360] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 09/11/2012] [Indexed: 01/01/2023] Open
Abstract
The molecular mechanism linking aldosterone and endothelin-1 in the development of diabetic nephropathy has not been completely elucidated. Here, we provide evidence showing that streptozotocin-induced diabetic rats have significantly increased aldosterone and endothelin-1 in the kidney tissue and markedly decreased expression of Dot1a and Af9. Blocking aldosterone with spironolactone significantly reduced proteinuria, glomerulosclerosis, tubulointerstitial injury and endothelin-1 expression, and significantly increased Dot1a and Af9 expression. Increasing Dot1a and Af9 expression by spironolactone or by stable transfection led to impaired endothelin-1 expression in NRK-52 cells. In contrast, downregulation of Dot1a and Af9 by aldosterone in NRK-52E cells caused upregulation of endothelin-1. Genetic inactivation of Dot1l, which encodes Dot1a, in Aqp2-expressing principal cells of mouse kidney impaired association of Dot1a and H3 dimethyl K79 with the specific subregions of endothelin-1 promoter, and upregulates endothelin-1 mRNA and protein expression. Our data suggest that Dot1a and Af9 repress endothelin-1 in vitro and in vivo. Excessive aldosterone induces kidney injury, in part possibly by downregulating Dot1a and Af9, and thus relieving Dot1a-Af9-mediated repression to increase endothelin-1 transcription. Spironolactone ameliorates kidney injury in Streptozotocin-induced diabetic rats, possibly by restoring Dot1a-Af9-mediated repression to reduce endothelin-1 expression. Therefore, Dot1a and Af9 as aldosterone-downregulated targets are negative regulators of endothelin-1 transcription in vitro and in vivo, and may be considered as new potential therapeutic targets of kidney injury in diabetes.
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22
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Duarte JD, Zineh I, Burkley B, Gong Y, Langaee TY, Turner ST, Chapman AB, Boerwinkle E, Gums JG, Cooper-DeHoff RM, Beitelshees AL, Bailey KR, Fillingim RB, Kone BC, Johnson JA. Effects of genetic variation in H3K79 methylation regulatory genes on clinical blood pressure and blood pressure response to hydrochlorothiazide. J Transl Med 2012; 10:56. [PMID: 22440088 PMCID: PMC3320544 DOI: 10.1186/1479-5876-10-56] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Accepted: 03/22/2012] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Nearly one-third of the United States adult population suffers from hypertension. Hydrochlorothiazide (HCTZ), one of the most commonly used medications to treat hypertension, has variable efficacy. The renal epithelial sodium channel (ENaC) provides a mechanism for fine-tuning sodium excretion, and is a major regulator of blood pressure homeostasis. DOT1L, MLLT3, SIRT1, and SGK1 encode genes in a pathway that controls methylation of the histone H3 globular domain at lysine 79 (H3K79), thereby modulating expression of the ENaCα subunit. This study aimed to determine the role of variation in these regulatory genes on blood pressure response to HCTZ, and secondarily, untreated blood pressure. METHODS We investigated associations between genetic variations in this candidate pathway and HCTZ blood pressure response in two separate hypertensive cohorts (clinicaltrials.gov NCT00246519 and NCT00005520). In a secondary, exploratory analysis, we measured associations between these same genetic variations and untreated blood pressure. Associations were measured by linear regression, with only associations with P ≤ 0.01 in one cohort and replication by P ≤ 0.05 in the other cohort considered significant. RESULTS In one cohort, a polymorphism in DOT1L (rs2269879) was strongly associated with greater systolic (P = 0.0002) and diastolic (P = 0.0016) blood pressure response to hydrochlorothiazide in Caucasians. However, this association was not replicated in the other cohort. When untreated blood pressure levels were analyzed, we found directionally similar associations between a polymorphism in MLLT3 (rs12350051) and greater untreated systolic (P < 0.01 in both cohorts) and diastolic (P < 0.05 in both cohorts) blood pressure levels in both cohorts. However, when further replication was attempted in a third hypertensive cohort and in smaller, normotensive samples, significant associations were not observed. CONCLUSIONS Our data suggest polymorphisms in DOT1L, MLLT3, SIRT1, and SGK1 are not likely associated with blood pressure response to HCTZ. However, a possibility exists that rs2269879 in DOT1L could be associated with HCTZ response in Caucasians. Additionally, exploratory analyses suggest rs12350051 in MLLT3 may be associated with untreated blood pressure in African-Americans. Replication efforts are needed to verify roles for these polymorphisms in human blood pressure regulation.
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Affiliation(s)
- Julio D Duarte
- Center for Pharmacogenomics and Department of Pharmacotherapy and Translational Research, University of Florida, Gainesville, FL 32610, USA
- Department of Pharmacy Practice, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Issam Zineh
- Center for Pharmacogenomics and Department of Pharmacotherapy and Translational Research, University of Florida, Gainesville, FL 32610, USA
- Office of Clinical Pharmacology, Office of Translational Sciences - CDER, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Ben Burkley
- Center for Pharmacogenomics and Department of Pharmacotherapy and Translational Research, University of Florida, Gainesville, FL 32610, USA
| | - Yan Gong
- Center for Pharmacogenomics and Department of Pharmacotherapy and Translational Research, University of Florida, Gainesville, FL 32610, USA
| | - Taimour Y Langaee
- Center for Pharmacogenomics and Department of Pharmacotherapy and Translational Research, University of Florida, Gainesville, FL 32610, USA
| | - Stephen T Turner
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
| | - Arlene B Chapman
- Renal Division, Department of Medicine, Emory University, Atlanta, GA 30322, USA
| | - Eric Boerwinkle
- Human Genetics Center and Institute of Molecular Medicine, University of Texas Health Science Center, Houston, TX 77030, USA
| | - John G Gums
- Center for Pharmacogenomics and Department of Pharmacotherapy and Translational Research, University of Florida, Gainesville, FL 32610, USA
| | - Rhonda M Cooper-DeHoff
- Center for Pharmacogenomics and Department of Pharmacotherapy and Translational Research, University of Florida, Gainesville, FL 32610, USA
| | - Amber L Beitelshees
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland, Baltimore, MD 21201, USA
| | - Kent R Bailey
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN 55905, USA
| | - Roger B Fillingim
- Department of Community Dentistry and Behavioral Science, University of Florida, Gainesville, FL 32610, USA
| | - Bruce C Kone
- Division of Nephrology, Hypertension & Renal Transplantation, University of Florida, Gainesville, FL 32610, USA
- Division of Renal Diseases and Hypertension, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Julie A Johnson
- Center for Pharmacogenomics and Department of Pharmacotherapy and Translational Research, University of Florida, Gainesville, FL 32610, USA
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