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Bazzell BG, Rainey WE, Auchus RJ, Zocco D, Bruttini M, Hummel SL, Byrd JB. Human Urinary mRNA as a Biomarker of Cardiovascular Disease. CIRCULATION-GENOMIC AND PRECISION MEDICINE 2019; 11:e002213. [PMID: 30354328 PMCID: PMC6760265 DOI: 10.1161/circgen.118.002213] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Supplemental Digital Content is available in the text. Background mRNA in urine supernatant (US-mRNA) might encode information about renal and cardiorenal pathophysiology, including hypertension. H, whether the US-mRNA transcriptome reflects that of renal tissues and whether changes in renal physiology are detectable using US-mRNA is unknown. Methods We compared transcriptomes of human urinary extracellular vesicles and human renal cortex. To avoid similarities attributable to ubiquitously expressed genes, we separately analyzed ubiquitously expressed and highly kidney-enriched genes. To determine whether US-mRNA reflects changes in renal gene expression, we assayed cell-depleted urine for transcription factor activity of mineralocorticoid receptors (MR) using probe-based quantitative polymerase chain reaction. The urine was collected from prehypertensive individuals (n=18) after 4 days on low-sodium diet to stimulate MR activity and again after suppression of MR activity via sodium infusion. Results In comparing this US-mRNA and human kidney cortex, expression of 55 highly kidney-enriched genes correlated strongly (rs=0.82) while 8457 ubiquitously expressed genes correlated moderately (rs=0.63). Standard renin-angiotensin-aldosterone system phenotyping confirmed the expected response to sodium loading. Cycle threshold values for MR-regulated targets (SCNN1A, SCNN1G, TSC22D3) changed after sodium loading, and MR-regulated targets (SCNN1A, SCNN1G, SGK1, and TSC22D3) correlated significantly with serum aldosterone and inversely with urinary sodium excretion. Conclusions RNA-sequencing of urinary extracellular vesicles shows concordance with human kidney. Perturbation in human endocrine signaling (MR activation) was accompanied by changes in mRNA in urine supernatant. Our findings could be useful for individualizing pharmacological therapy in patients with disorders of mineralocorticoid signaling, such as resistant hypertension. More generally, these insights could be used to noninvasively identify putative biomarkers of disordered renal and cardiorenal physiology.
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Affiliation(s)
- Brian G Bazzell
- Departments of Internal Medicine, University of Michigan, Ann Arbor (B.G.B., R.J.A., S.L.H., J.B.B.)
| | - William E Rainey
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor (W.E.R.)
| | - Richard J Auchus
- Departments of Internal Medicine, University of Michigan, Ann Arbor (B.G.B., R.J.A., S.L.H., J.B.B.)
| | | | - Marco Bruttini
- Department of Life Sciences, Università degli Studi di Siena, Italy (M.B.)
| | - Scott L Hummel
- Departments of Internal Medicine, University of Michigan, Ann Arbor (B.G.B., R.J.A., S.L.H., J.B.B.).,Section of Cardiology, Ann Arbor Veterans Affairs Medical Center, MI (S.L.H.)
| | - James Brian Byrd
- Departments of Internal Medicine, University of Michigan, Ann Arbor (B.G.B., R.J.A., S.L.H., J.B.B.)
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Abstract
OBJECTIVES The goal of this study was to investigate genes associated with essential hypertension from a system perspective, making use of bioinformatic tools to gain insights that are not evident when focusing at a detail-based resolution. METHODS Using various databases (pathways, Genome Wide Association Studies, knockouts etc.), we compiled a set of about 200 genes that play a major role in hypertension and identified the interactions between them. This enabled us to create a protein-protein interaction network graph, from which we identified key elements, based on graph centrality analysis. Enriched gene regulatory elements (transcription factors and microRNAs) were extracted by motif finding techniques and knowledge-based tools. RESULTS We found that the network is composed of modules associated with functions such as water retention, endothelial vasoconstriction, sympathetic activity and others. We identified the transcription factor SP1 and the two microRNAs miR27 (a and b) and miR548c-3p that seem to play a major role in regulating the network as they exert their control over several modules and are not restricted to specific functions. We also noticed that genes involved in metabolic diseases (e.g. insulin) are central to the network. CONCLUSION We view the blood-pressure regulation mechanism as a system-of-systems, composed of several contributing subsystems and pathways rather than a single module. The system is regulated by distributed elements. Understanding this mode of action can lead to a more precise treatment and drug target discovery. Our analysis suggests that insulin plays a primary role in hypertension, highlighting the tight link between essential hypertension and diseases associated with the metabolic syndrome.
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Rossier BC, Baker ME, Studer RA. Epithelial sodium transport and its control by aldosterone: the story of our internal environment revisited. Physiol Rev 2015; 95:297-340. [PMID: 25540145 DOI: 10.1152/physrev.00011.2014] [Citation(s) in RCA: 155] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Transcription and translation require a high concentration of potassium across the entire tree of life. The conservation of a high intracellular potassium was an absolute requirement for the evolution of life on Earth. This was achieved by the interplay of P- and V-ATPases that can set up electrochemical gradients across the cell membrane, an energetically costly process requiring the synthesis of ATP by F-ATPases. In animals, the control of an extracellular compartment was achieved by the emergence of multicellular organisms able to produce tight epithelial barriers creating a stable extracellular milieu. Finally, the adaptation to a terrestrian environment was achieved by the evolution of distinct regulatory pathways allowing salt and water conservation. In this review we emphasize the critical and dual role of Na(+)-K(+)-ATPase in the control of the ionic composition of the extracellular fluid and the renin-angiotensin-aldosterone system (RAAS) in salt and water conservation in vertebrates. The action of aldosterone on transepithelial sodium transport by activation of the epithelial sodium channel (ENaC) at the apical membrane and that of Na(+)-K(+)-ATPase at the basolateral membrane may have evolved in lungfish before the emergence of tetrapods. Finally, we discuss the implication of RAAS in the origin of the present pandemia of hypertension and its associated cardiovascular diseases.
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Affiliation(s)
- Bernard C Rossier
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; Division of Nephrology-Hypertension, University of California San Diego, La Jolla, California; and Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Michael E Baker
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; Division of Nephrology-Hypertension, University of California San Diego, La Jolla, California; and Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Romain A Studer
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; Division of Nephrology-Hypertension, University of California San Diego, La Jolla, California; and Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
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Greenlee MM, Mitzelfelt JD, Duke BJ, Al-Khalili O, Bao HF, Eaton DC. Prolactin stimulates sodium and chloride ion channels in A6 renal epithelial cells. Am J Physiol Renal Physiol 2015; 308:F697-705. [PMID: 25587116 DOI: 10.1152/ajprenal.00270.2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 01/07/2015] [Indexed: 11/22/2022] Open
Abstract
Many hormonal pathways contribute to the regulation of renal epithelial sodium channel (ENaC) function, a key process for maintaining blood volume and controlling blood pressure. In the present study, we examined whether the peptide hormone prolactin (PRL) regulates ENaC function in renal epithelial cells (A6). Basolateral application of several different concentrations of PRL dramatically stimulated the transepithelial current in A6 cells, increasing both amiloride-sensitive (ENaC) and amiloride-insensitive currents. Using cell-attached patch clamp, we determined that PRL increased both the number (N) and open probability (Po) of ENaC present in the apical membrane. Inhibition of PKA with H-89 abolished the effect of PRL on amiloride-sensitive and insensitive transepithelial currents and eliminated the increase in ENaC NPo with PRL exposure. PRL also increased cAMP in A6 cells, consistent with signaling through the cAMP-dependent PKA pathway. We also identified that PRL induced activity of a 2-pS anion channel with outward rectification, electrophysiological properties consistent with ClC4 or ClC5. RT-PCR only detected ClC4, but not ClC5 transcripts. Here, we show for the first time that PRL activates sodium and chloride transport in renal epithelial cells via ENaC and ClC4.
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Affiliation(s)
- Megan M Greenlee
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | | | - Billie Jeanne Duke
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | - Otor Al-Khalili
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | - Hui-Fang Bao
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | - Douglas C Eaton
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
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Natekar A, Olds RL, Lau MW, Min K, Imoto K, Slavin TP. Elevated blood pressure: Our family's fault? The genetics of essential hypertension. World J Cardiol 2014; 6:327-37. [PMID: 24944762 PMCID: PMC4062117 DOI: 10.4330/wjc.v6.i5.327] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 02/10/2014] [Accepted: 04/16/2014] [Indexed: 02/06/2023] Open
Abstract
AIM To provide an updated review on current genetic aspects possibly affecting essential hypertension (EH), and to further elucidate their role in EH. METHODS We searched for genetic and epigenetic factors in major studies associated with EH between Jan 2008-Oct 2013 using PubMed. We limited our search to reviews that discussed mostly human studies, and were accessible through the university online resource. We found 11 genome wide association studies (GWAS), as well as five methylation and three miRNA studies that fit our search criteria. A distinction was not made between genes with protective effects or negative effects, as this article is only meant to be a summary of genes associated with any aspect of EH. RESULTS We found 130 genes from the studies that met our inclusion/exclusion criteria. Of note, genes with multiple study references include: STK39, CYP17A1, MTHFR-NPPA, MTHFR-NPPB, ATP2B1, CSK, ZNF652, UMOD, CACNB2, PLEKHA7, SH2B3, TBX3-TBX5, ULK4, CSK-ULK3, CYP1A2, NT5C2, CYP171A, PLCD3, SH2B3, ATXN2, CACNB2, PLEKHA7, SH2B3, TBX3-TBX5, ULK4, and HFE. The following genes overlapped between the genetic studies and epigenetic studies: WNK4 and BDKRB2. Several of the identified genes were found to have functions associated with EH. Many epigenetic factors were also correlated with EH. Of the epigenetic factors, there were no articles discussing siRNA and its effects on EH that met the search criteria, thus the topic was not included in this review. Among the miRNA targets found to be associated with EH, many of the genes involved were also identified in the GWAS studies. CONCLUSION Genetic hypertension risk algorithms could be developed in the future but may be of limited benefit due to the multi-factorial nature of EH. With emerging technologies, like next-generation sequencing, more direct causal relationships between genetic and epigenetic factors affecting EH will likely be discovered creating a tremendous potential for personalized medicine using pharmacogenomics.
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Affiliation(s)
- Aniket Natekar
- Aniket Natekar, Randi L Olds, Meghann W Lau, Kathleen Min, Karra Imoto, Thomas P Slavin, The John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, United States
| | - Randi L Olds
- Aniket Natekar, Randi L Olds, Meghann W Lau, Kathleen Min, Karra Imoto, Thomas P Slavin, The John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, United States
| | - Meghann W Lau
- Aniket Natekar, Randi L Olds, Meghann W Lau, Kathleen Min, Karra Imoto, Thomas P Slavin, The John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, United States
| | - Kathleen Min
- Aniket Natekar, Randi L Olds, Meghann W Lau, Kathleen Min, Karra Imoto, Thomas P Slavin, The John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, United States
| | - Karra Imoto
- Aniket Natekar, Randi L Olds, Meghann W Lau, Kathleen Min, Karra Imoto, Thomas P Slavin, The John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, United States
| | - Thomas P Slavin
- Aniket Natekar, Randi L Olds, Meghann W Lau, Kathleen Min, Karra Imoto, Thomas P Slavin, The John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, United States
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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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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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