1
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Wei W, Zhao Y, Chai Y, Shou S, Jin H. A novel role of DOT1L in kidney diseases. Mol Biol Rep 2023; 50:5415-5423. [PMID: 37085741 DOI: 10.1007/s11033-023-08415-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 03/29/2023] [Indexed: 04/23/2023]
Abstract
BACKGROUND We systematically summarized the structure and biological function of DOT1L in detail, and further discussed the role of DOT1L in kidney diseases through different mechanisms. METHODS AND RESULTS We first described the role of DOT1L in various kidney diseases including AKI, CKD, DN and kidney tumor diseases. CONCLUSIONS A better understanding of DOT1L as a histone methylase based on characteristics of regulating telomere silencing, transcriptional extension, DNA damage repair and cell cycle could lead to the development of new therapeutic targets for various kidney diseases, thereby improving the prognosis of kidney disease patients.
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Affiliation(s)
- Wei Wei
- Department of Emergency Medicine, Tianjin Medical University General Hospital, Tianjin, 300052, People's Republic of China
| | - Yibo Zhao
- Department of Emergency Medicine, Tianjin Medical University General Hospital, Tianjin, 300052, People's Republic of China
| | - Yanfen Chai
- Department of Emergency Medicine, Tianjin Medical University General Hospital, Tianjin, 300052, People's Republic of China
| | - Songtao Shou
- Department of Emergency Medicine, Tianjin Medical University General Hospital, Tianjin, 300052, People's Republic of China.
| | - Heng Jin
- Department of Emergency Medicine, Tianjin Medical University General Hospital, Tianjin, 300052, People's Republic of China.
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2
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Zhong S, Zhang B, Qin L, Wang Q, Luo X. Aldosterone inhibits Dot1l expression in guinea pig cochlea. Eur J Med Res 2023; 28:26. [PMID: 36639782 PMCID: PMC9838020 DOI: 10.1186/s40001-023-00994-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 01/04/2023] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Aldosterone relieves transcriptional repression of epithelial sodium channel (ENaC) by inhibiting Dot1a and Af9 expression and their interaction with ENaC promoter in various tissues. Expressions of ENaC and Af9 in inner ear have been identified. However, it is not known how Dot1l is regulated by aldosterone in inner ear. METHODS Twenty-eight adult guinea pigs were randomly divided into the control group and treatment group. Aldosterone 1 mg/kg/d was injected intraperitoneally in the treatment group and saline in the control group for 7 days. Animals were killed 1 month later following auditory brainstem response examination. Histomorphology of cochlea was detected with hematoxylin-eosin staining, and Dot1l expression was examined with immunohistochemistry and Western blot. RESULTS There was no significant difference in ABR thresholds before and after injection of aldosterone or saline in either group. Endolymphatic hydrops was found in 75% of animals in the treatment group. Dot1l was found in both groups in the stria vascularis, Reissner's membrane, spiral limbus, organ of Corti and spiral ligament. Dot1l expression in the treatment group was decreased by aldosterone. CONCLUSIONS Dot1l in guinea pig cochlea is inhibited by aldosterone with induction of endolymphatic hydrops. Dot1l may be closely related to endolymph regulation by aldosterone and to pathogenesis of Meniere's disease.
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Affiliation(s)
- Shixun Zhong
- grid.452206.70000 0004 1758 417XDepartment of Otolaryngology, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Yuzhong District, Chongqing, 400016 China
| | - Biyun Zhang
- grid.452206.70000 0004 1758 417XDepartment of Otolaryngology, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Yuzhong District, Chongqing, 400016 China
| | - Li Qin
- grid.490255.f0000 0004 7594 4364 Department of Otolaryngology, Mianyang Central Hospital, Mianyang, China
| | - Qianying Wang
- grid.452206.70000 0004 1758 417XDepartment of Otolaryngology, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Yuzhong District, Chongqing, 400016 China
| | - Xiaoli Luo
- Department of Otolaryngology, Chongqing Traditional Chinese Medicine Hospital, Chongqing, China
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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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4
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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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Chen L, Higgins PJ, Zhang W. Development and Diseases of the Collecting Duct System. Results Probl Cell Differ 2017; 60:165-203. [PMID: 28409346 DOI: 10.1007/978-3-319-51436-9_7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The collecting duct of the mammalian kidney is important for the regulation of extracellular volume, osmolarity, and pH. There are two major structurally and functionally distinct cell types: principal cells and intercalated cells. The former regulates Na+ and water homeostasis, while the latter participates in acid-base homeostasis. In vivo lineage tracing using Cre recombinase or its derivatives such as CreGFP and CreERT2 is a powerful new technique to identify stem/progenitor cells in their native environment and to decipher the origins of the tissue that they give rise to. Recent studies using this technique in mice have revealed multiple renal progenitor cell populations that differentiate into various nephron segments and collecting duct. In particular, emerging evidence suggests that like principal cells, most of intercalated cells originate from the progenitor cells expressing water channel Aquaporin 2. Mutations or malfunctions of the channels, pumps, and transporters expressed in the collecting duct system cause various human diseases. For example, gain-of-function mutations in ENaC cause Liddle's syndrome, while loss-of-function mutations in ENaC lead to Pseudohypoaldosteronism type 1. Mutations in either AE1 or V-ATPase B1 result in distal renal tubular acidosis. Patients with disrupted AQP2 or AVPR2 develop nephrogenic diabetes insipidus. A better understanding of the function and development of the collecting duct system may facilitate the discovery of new therapeutic strategies for treating kidney disease.
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Affiliation(s)
- Lihe Chen
- Epithelial Systems Biology Laboratory, Systems Biology Center, NHLBI, Bethesda, MD, 20892-1603, USA
| | - Paul J Higgins
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, MC-165, 47 New Scotland Avenue, Albany, NY, 12208, USA
| | - Wenzheng Zhang
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, MC-165, 47 New Scotland Avenue, Albany, NY, 12208, USA.
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Wanner N, Bechtel-Walz W. Epigenetics of kidney disease. Cell Tissue Res 2017; 369:75-92. [PMID: 28286899 DOI: 10.1007/s00441-017-2588-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Accepted: 02/15/2017] [Indexed: 02/06/2023]
Abstract
DNA methylation and histone modifications determine renal programming and the development and progression of renal disease. The identification of the way in which the renal cell epigenome is altered by environmental modifiers driving the onset and progression of renal diseases has extended our understanding of the pathophysiology of kidney disease progression. In this review, we focus on current knowledge concerning the implications of epigenetic modifications during renal disease from early development to chronic kidney disease progression including renal fibrosis, diabetic nephropathy and the translational potential of identifying new biomarkers and treatments for the prevention and therapy of chronic kidney disease and end-stage kidney disease.
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Affiliation(s)
- Nicola Wanner
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Freiburg, Germany. .,Center for Systems Biology (ZBSA), Albert-Ludwigs-University, Freiburg, Germany. .,Renal Division, University Hospital Freiburg, Breisacher Strasse 66, 79106, Freiburg, Germany.
| | - Wibke Bechtel-Walz
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Freiburg, Germany. .,Renal Division, University Hospital Freiburg, Breisacher Strasse 66, 79106, Freiburg, Germany.
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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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9
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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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10
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Recent developments in epigenetics of acute and chronic kidney diseases. Kidney Int 2015; 88:250-61. [PMID: 25993323 PMCID: PMC4522401 DOI: 10.1038/ki.2015.148] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/22/2015] [Accepted: 03/30/2015] [Indexed: 12/25/2022]
Abstract
The growing epidemic of obesity and diabetes, the aging population as well as prevalence of drug abuse has led to significant increases in the rates of the closely associated acute and chronic kidney diseases, including diabetic nephropathy. Furthermore, evidence shows that parental behavior and diet can affect the phenotype of subsequent generations via epigenetic transmission mechanisms. These data suggest a strong influence of the environment on disease susceptibility and that, apart from genetic susceptibility, epigenetic mechanisms need to be evaluated to gain critical new information about kidney diseases. Epigenetics is the study of processes that control gene expression and phenotype without alterations in the underlying DNA sequence. Epigenetic modifications, including cytosine DNA methylation and covalent post translational modifications of histones in chromatin are part of the epigenome, the interface between the stable genome and the variable environment. This dynamic epigenetic layer responds to external environmental cues to influence the expression of genes associated with disease states. The field of epigenetics has seen remarkable growth in the past few years with significant advances in basic biology, contributions to human disease, as well as epigenomics technologies. Further understanding of how the renal cell epigenome is altered by metabolic and other stimuli can yield novel new insights into the pathogenesis of kidney diseases. In this review, we have discussed the current knowledge on the role of epigenetic mechanisms (primarily DNA me and histone modifications) in acute and chronic kidney diseases, and their translational potential to identify much needed new therapies.
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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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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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13
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Physical and functional interaction of Rnf2 with Af9 regulates basal and aldosterone-stimulated transcription of the α-ENaC gene in a renal collecting duct cell line. Biosci Rep 2013; 33:BSR20130086. [PMID: 24070375 PMCID: PMC3979232 DOI: 10.1042/bsr20130086] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The physical and functional interaction of Rnf2 (RING finger protein 2), a central component of the PRC (Polycomb repressive complex) 1 and Af9 (ALL1-fused gene from chromosome 9 protein), an aldosterone-sensitive transcription factor, in regulating basal and aldosterone-stimulated transcription of the α-ENaC (epithelial Na+ channel α-subunit) gene was explored in mIMCD3 CD (collecting duct) cells. Since Rnf2 lacks DNA-specific binding activity, other factors must mediate its site-specific chromatin recruitment. Rnf2 and Af9 co-localized in the nucleus and co-immunoprecipitated. A GST (glutathione transferase)-Af9 carboxy-terminal fusion protein directly interacted with in vitro translated Rnf2 in GST pull-down assays. Rnf2 knock down enhanced basal and aldosterone-stimulated α-ENaC mRNA levels and α-ENaC promoter activity. ChIP/QPCR (chromatin immunoprecipitation/quantitative PCR) assays demonstrated enrichment of Rnf2, H2AK119 (mono-ubiquitinated histone H2A lysine 119), and H3K27me3 (histone H3 lysine 27 trimethylated), a PRC2 chromatin mark, at multiple α-ENaC promoter subregions corresponding to regions of known Af9 enrichment, under basal conditions. Sequential ChIP confirmed Rnf2-Af9 co-occupancy of the α-ENaC promoter. Aldosterone provoked early and sustained depletion of Rnf2, ubiquitinated H2AK119, and trimethylated H3K27 associated with the subregions of the α-ENaC promoter. Thus, Af9 mediates site-selective physical and functional recruitment of Rnf2 to the α-ENaC promoter to constrain basal α-ENaC transcription in collecting duct cells, and aldosterone reverses this process.
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14
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Yu Z, Kong Q, Kone BC. Aldosterone reprograms promoter methylation to regulate αENaC transcription in the collecting duct. Am J Physiol Renal Physiol 2013; 305:F1006-13. [PMID: 23926181 PMCID: PMC3798741 DOI: 10.1152/ajprenal.00407.2013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 07/30/2013] [Indexed: 02/06/2023] Open
Abstract
Aldosterone increases tubular Na(+) absorption largely by increasing α-epithelial Na(+) channel (αENaC) transcription in collecting duct principal cells. How aldosterone reprograms basal αENaC transcription to high-level activity in the collecting duct is incompletely understood. Promoter methylation, a covalent but reversible epigenetic process, has been implicated in the control of gene expression in health and disease. We investigated the role of promoter methylation/demethylation in the epigenetic control of basal and aldosterone-stimulated αENaC transcription in mIMCD3 collecting duct cells. Bisulfite treatment and sequencing analysis after treatment of the cells with the DNA methyltransferase (DNMT) inhibitor 5-aza-2'-deoxycytidine (5-Aza-CdR) identified clusters of methylated cytosines in a CpG island near the transcription start site of the αENaC promoter. 5-Aza-CdR treatment or small interfering RNA-mediated knockdown of DNMT3b or methyl-CpG-binding domain protein (MBD)-4 derepressed basal αENaC transcription, indicating that promoter methylation suppresses basal αENaC transcription. Aldosterone triggered a time-dependent decrease in 5mC and DNMT3b and a concurrent enrichment in 5-hydroxymethylcytosine (5hmC) and ten-eleven translocation (Tet)2 at the αENaC promoter, consistent with active demethylation. 5-Aza-CdR mimicked aldosterone by enhancing Sp1 binding to the αENaC promoter. We conclude that DNMT3b- and MBD4-dependent methylation of the αENaC promoter limits basal αENaC transcription, in part by limiting Sp1 binding and trans-activation. Aldosterone stimulates the dispersal of DNMT3b and recruitment of Tet2 to demethylate the αENaC promoter to induce αENaC transcription. These results disclose a novel epigenetic mechanism for the control of basal and aldosterone-induced αENaC transcription that adds to previously described epigenetic controls exerted by histone modifications.
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Affiliation(s)
- Zhiyuan Yu
- Div. of Renal Diseases and Hypertension, The Univ. of Texas Medical School at Houston, 6431 Fannin, MSB 5.124, Houston, TX 77030.
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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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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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Yu Z, Kong Q, Kone BC. Sp1 trans-activates and is required for maximal aldosterone induction of the αENaC gene in collecting duct cells. Am J Physiol Renal Physiol 2013; 305:F653-62. [PMID: 23804453 DOI: 10.1152/ajprenal.00177.2013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The epithelial Na+ channel (ENaC) in the distal nephron constitutes the rate-limiting step for renal sodium reabsorption. Aldosterone increases tubular sodium absorption in large part by increasing αENaC transcription in collecting duct principal cells. We previously reported that Af9 binds to +78/+92 of αENaC and recruits Dot1a to repress basal and aldosterone-sensitive αENaC transcription in mouse inner medullary collecting duct (mIMCD)3 cells. Despite this epigenetic repression, basal αENaC transcription is still evident and physiologically necessary, indicating basal operation of positive regulators. In the present study, we identified Sp1 as one such regulator. Gel shift and antibody competition assays using a +208/+240 probe revealed DNA-Sp1-containing complexes in mIMCD3 cells. Mutation of the +222/+229 element abrogated Sp1 binding in vitro and in promoter-reporter constructs stably expressed in mIMCD3 cells. Compared with the wild-type promoter, an αENaC promoter-luciferase construct with +222/+229 mutations exhibited much lower activity and impaired trans-activation in Sp1 overexpression experiments. Conversely, Sp1 knockdown inhibited endogenous αENaC mRNA and the activity of the wild-type αENaC promoter but not the mutated construct. Aldosterone triggered Sp1 recruitment to the αENaC promoter, which was required for maximal induction of αENaC promoter activity and was blocked by spironolactone. Sequential chromatin immunoprecipitation assays and functional tests of +78/+92 and +222/+229 αENaC promoter mutants indicated that while Sp1, Dot1a, and Af9 co-occupy the αENaC promoter, the Sp1 effects are functionally independent from Dot1a and Af9. In summary, Sp1 binding to a cis-element at +222/+229 represents the first identified constitutive driver of αENaC transcription, and it contributes to maximal aldosterone trans-activation of αENaC.
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Affiliation(s)
- Zhiyuan Yu
- Div. of Renal Diseases and Hypertension, The Univ. of Texas Medical School at Houston, 6431 Fannin, MSB 5.124, Houston, TX 77030, USA
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