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Drug-Targeted Genomes: Mutability of Ion Channels and GPCRs. Biomedicines 2022; 10:biomedicines10030594. [PMID: 35327396 PMCID: PMC8945769 DOI: 10.3390/biomedicines10030594] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 02/24/2022] [Accepted: 03/01/2022] [Indexed: 02/04/2023] Open
Abstract
Mutations of ion channels and G-protein-coupled receptors (GPCRs) are not uncommon and can lead to cardiovascular diseases. Given previously reported multiple factors associated with high mutation rates, we sorted the relative mutability of multiple human genes by (i) proximity to telomeres and/or (ii) high adenine and thymine (A+T) content. We extracted genomic information using the genome data viewer and examined the mutability of 118 ion channel and 143 GPCR genes based on their association with factors (i) and (ii). We then assessed these two factors with 31 genes encoding ion channels or GPCRs that are targeted by the United States Food and Drug Administration (FDA)-approved drugs. Out of the 118 ion channel genes studied, 80 met either factor (i) or (ii), resulting in a 68% match. In contrast, a 78% match was found for the 143 GPCR genes. We also found that the GPCR genes (n = 20) targeted by FDA-approved drugs have a relatively lower mutability than those genes encoding ion channels (n = 11), where targeted genes encoding GPCRs were shorter in length. The result of this study suggests that the use of matching rate analysis on factor-druggable genome is feasible to systematically compare the relative mutability of GPCRs and ion channels. The analysis on chromosomes by two factors identified a unique characteristic of GPCRs, which have a significant relationship between their nucleotide sizes and proximity to telomeres, unlike most genetic loci susceptible to human diseases.
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2
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Gonzalez-Fernandez E, Fan L, Wang S, Liu Y, Gao W, Thomas KN, Fan F, Roman RJ. The adducin saga: pleiotropic genomic targets for precision medicine in human hypertension-vascular, renal, and cognitive diseases. Physiol Genomics 2022; 54:58-70. [PMID: 34859687 PMCID: PMC8799388 DOI: 10.1152/physiolgenomics.00119.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/23/2021] [Accepted: 11/29/2021] [Indexed: 02/03/2023] Open
Abstract
Hypertension is a leading risk factor for stroke, heart disease, chronic kidney disease, vascular cognitive impairment, and Alzheimer's disease. Previous genetic studies have nominated hundreds of genes linked to hypertension, and renal and cognitive diseases. Some have been advanced as candidate genes by showing that they can alter blood pressure or renal and cerebral vascular function in knockout animals; however, final validation of the causal variants and underlying mechanisms has remained elusive. This review chronicles 40 years of work, from the initial identification of adducin (ADD) as an ACTIN-binding protein suggested to increase blood pressure in Milan hypertensive rats, to the discovery of a mutation in ADD1 as a candidate gene for hypertension in rats that were subsequently linked to hypertension in man. More recently, a recessive K572Q mutation in ADD3 was identified in Fawn-Hooded Hypertensive (FHH) and Milan Normotensive (MNS) rats that develop renal disease, which is absent in resistant strains. ADD3 dimerizes with ADD1 to form functional ADD protein. The mutation in ADD3 disrupts a critical ACTIN-binding site necessary for its interactions with actin and spectrin to regulate the cytoskeleton. Studies using Add3 KO and transgenic strains, as well as a genetic complementation study in FHH and MNS rats, confirmed that the K572Q mutation in ADD3 plays a causal role in altering the myogenic response and autoregulation of renal and cerebral blood flow, resulting in increased susceptibility to hypertension-induced renal disease and cerebral vascular and cognitive dysfunction.
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Affiliation(s)
- Ezekiel Gonzalez-Fernandez
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Letao Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Shaoxun Wang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Yedan Liu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Wenjun Gao
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Kirby N Thomas
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
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3
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Citterio L, Bianchi G, Scioli GA, Glorioso N, Bigazzi R, Cusi D, Staessen JA, Cavuto S, Ferrandi M, Lanzani C, Li X, Lau LF, Chiang CE, Wang TD, Wang KL, Ferrari P, Manunta P. Antihypertensive treatment guided by genetics: PEARL-HT, the randomized proof-of-concept trial comparing rostafuroxin with losartan. THE PHARMACOGENOMICS JOURNAL 2021; 21:346-358. [PMID: 33649520 PMCID: PMC8159753 DOI: 10.1038/s41397-021-00214-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 01/14/2021] [Accepted: 01/27/2021] [Indexed: 12/22/2022]
Abstract
We compared a standard antihypertensive losartan treatment with a pharmacogenomics-guided rostafuroxin treatment in never-treated Caucasian and Chinese patients with primary hypertension. Rostafuroxin is a digitoxigenin derivative that selectively disrupts the binding to the cSrc-SH2 domain of mutant α-adducin and of the ouabain-activated Na-K pump at 10-11 M. Of 902 patients screened, 172 were enrolled in Italy and 107 in Taiwan. After stratification for country and genetic background, patients were randomized to rostafuroxin or losartan, being the difference in the fall in office systolic blood pressure (OSBP) after 2-month treatment the primary endpoint. Three pharmacogenomic profiles (P) were examined, considering: P1, adding to the gene variants included in the subsequent P2, the variants detected by post-hoc analysis of a previous trial; P2, variants of genes encoding enzymes for endogenous ouabain (EO) synthesis (LSS and HSD3B1), EO transport (MDR1/ABCB1), adducin (ADD1 and ADD3); P3, variants of the LSS gene only. In Caucasians, the group differences (rostafuroxin 50 μg minus losartan 50 mg in OSBP mmHg) were significant both in P2 adjusted for genetic heterogeneity (P2a) and P3 LSS rs2254524 AA [9.8 (0.6-19.0), P = 0.038 and 13.4 (25.4-2.5), P = 0.031, respectively]. In human H295R cells transfected with LSS A and LSS C variants, the EO production was greater in the former (P = 0.038); this difference was abolished by rostafuroxin at 10-11 M. Chinese patients had a similar drop in OSBP to Caucasians with losartan but no change in OSBP with rostafuroxin. These results show that genetics may guide drug treatment for primary hypertension in Caucasians.
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Affiliation(s)
- Lorena Citterio
- Genomics of Renal Diseases and Hypertension Unit, IRCCS San Raffaele Scientific Institute, Università Vita Salute San Raffaele, Milano, Italy.,Università Vita Salute San Raffaele, Milan, Italy
| | | | - Giuseppe A Scioli
- Hypertension and Cardiovascular Prevention Center, Ospedale Ferdinando Veneziale, Isernia, Italy
| | - Nicola Glorioso
- Hypertension and Related Diseases Center, Department of Clinical and Experimental Medicine, University of Sassari, Sassari, Italy
| | | | - Daniele Cusi
- Institute of Biomedical Technologies Milano National Research Council of Italy (CNR), Segrate, Milano, Italy.,Bio4Dreams Scientific Unit, Bio4Dreams-Business Nursery for Life Sciences, Milano, Italy
| | - Jan A Staessen
- Research Unit Hypertension and Cardiovascular Epidemiology KU Leuven Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
| | - Silvio Cavuto
- Clinical Trials and Statistics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | | | - Chiara Lanzani
- Genomics of Renal Diseases and Hypertension Unit, IRCCS San Raffaele Scientific Institute, Università Vita Salute San Raffaele, Milano, Italy.,Università Vita Salute San Raffaele, Milan, Italy
| | | | - Lit-Fui Lau
- Zhaoke (Guangzhou) Ophthalmology Pharmaceutical Limited, Guangzhou, China
| | - Chern-En Chiang
- General Clinical Research Center, Taipei Veterans General Hospital and National Yang-Ming University, Taipei, Taiwan
| | - Tzung-Dau Wang
- Cardiovascular Center and Division of Cardiology, Department of Internal Medicine, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Kang-Ling Wang
- General Clinical Research Center, Taipei Veterans General Hospital and National Yang-Ming University, Taipei, Taiwan
| | | | - Paolo Manunta
- Genomics of Renal Diseases and Hypertension Unit, IRCCS San Raffaele Scientific Institute, Università Vita Salute San Raffaele, Milano, Italy.,Università Vita Salute San Raffaele, Milan, Italy
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4
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Fan F, Geurts AM, Pabbidi MR, Ge Y, Zhang C, Wang S, Liu Y, Gao W, Guo Y, Li L, He X, Lv W, Muroya Y, Hirata T, Prokop J, Booz GW, Jacob HJ, Roman RJ. A Mutation in γ-Adducin Impairs Autoregulation of Renal Blood Flow and Promotes the Development of Kidney Disease. J Am Soc Nephrol 2020; 31:687-700. [PMID: 32029431 DOI: 10.1681/asn.2019080784] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 12/14/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The genes and mechanisms involved in the association between diabetes or hypertension and CKD risk are unclear. Previous studies have implicated a role for γ-adducin (ADD3), a cytoskeletal protein encoded by Add3. METHODS We investigated renal vascular function in vitro and in vivo and the susceptibility to CKD in rats with wild-type or mutated Add3 and in genetically modified rats with overexpression or knockout of ADD3. We also studied glomeruli and primary renal vascular smooth muscle cells isolated from these rats. RESULTS This study identified a K572Q mutation in ADD3 in fawn-hooded hypertensive (FHH) rats-a mutation previously reported in Milan normotensive (MNS) rats that also develop kidney disease. Using molecular dynamic simulations, we found that this mutation destabilizes a critical ADD3-ACTIN binding site. A reduction of ADD3 expression in membrane fractions prepared from the kidney and renal vascular smooth muscle cells of FHH rats was associated with the disruption of the F-actin cytoskeleton. Compared with renal vascular smooth muscle cells from Add3 transgenic rats, those from FHH rats had elevated membrane expression of BKα and BK channel current. FHH and Add3 knockout rats exhibited impairments in the myogenic response of afferent arterioles and in renal blood flow autoregulation, which were rescued in Add3 transgenic rats. We confirmed these findings in a genetic complementation study that involved crossing FHH and MNS rats that share the ADD3 mutation. Add3 transgenic rats showed attenuation of proteinuria, glomerular injury, and kidney fibrosis with aging and mineralocorticoid-induced hypertension. CONCLUSIONS This is the first report that a mutation in ADD3 that alters ACTIN binding causes renal vascular dysfunction and promotes the susceptibility to kidney disease.
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Affiliation(s)
- Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Aron M Geurts
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Mallikarjuna R Pabbidi
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Ying Ge
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Chao Zhang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Shaoxun Wang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Yedan Liu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Wenjun Gao
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Ya Guo
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Longyang Li
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Xiaochen He
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Wenshan Lv
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Yoshikazu Muroya
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Takashi Hirata
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Jeremy Prokop
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
| | - George W Booz
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Howard J Jacob
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi;
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5
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Bigazzi R, Zagato L, Lanzani C, Fontana S, Messaggio E, Delli Carpini S, Citterio L, Simonini M, Brioni E, Magnaghi C, Colombo GI, Santini G, Nistri F, Cellai F, Lenti S, Bianchi S, Pertosa GB, Rocchetti MT, Papale M, Mezzolla V, Gesualdo L, Pina Concas M, Campese V, Manunta P. Hypertension in High School Students: Genetic and Environmental Factors. Hypertension 2020; 75:71-78. [DOI: 10.1161/hypertensionaha.119.13818] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Hypertension and obesity in the young population are major risk factors for renal and cardiovascular events, which could arise in adulthood. A candidate-gene approach was applied in a cohort observational study, in which we collected data from 2638 high school adolescent students. Participants underwent anthropometric and blood pressure (BP) measurements, as well as saliva and urine sample collection for genomic DNA extraction and renal function evaluation, respectively. We tested whether candidate genes previously implicated in salt-sensitive hypertension in adults impact BP also among adolescents. Since inflammatory mechanisms may be involved in pathophysiology of hypertension and in endothelial dysfunction and atherosclerosis through reactive oxygen species, the baseline urinary excretion of inflammatory and oxidative stress markers in a subgroup of adolescents stratified according to
ADD1
(alpha adducin) rs4961 genotypes was assessed. Regression analysis of BP values with genetic polymorphisms, highlighted an association with a missense variant of
LSS
(lanosterol synthase, rs2254524), a gene coding for an enzyme involved in endogenous ouabain synthesis. Higher diastolic and systolic BP were associated with
LSS
A allele (
P
=0.011 and
P
=0.023, respectively). BP resulted associated with 5 more SNPs. The
KL
(klotho) rs9536314 missense variant was associated with 24 hour urinary Na
+
excretion (
P
=0.0083). Urinary protein tests showed a greater excretion of IL1β (interleukin 1β) and interleukin 10 (
P
<0.0001) in carriers of the
ADD1
rs4961 T allele. In conclusion, 3 missense gene variants already implicated in adult hypertension impact BP or Na
+
excretion among adolescents, and, together with activated pro-inflammatory pathways, might predispose to early cardiovascular damage.
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Affiliation(s)
- Roberto Bigazzi
- From the Nephrology and Dialysis Complex Operative Unit, ASL Nord Ovest Toscana, Livorno, Italy (R.B., G.S., F.N., F.C., S.B.)
| | - Laura Zagato
- Chair of Nephrology Vita-Salute University San Raffaele and Genomics of Renal Diseases and Hypertension Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy (L.Z., C.L., S.F., E.M., S.D.C., L.C., M.S., E.B., C.M., P.M.)
| | - Chiara Lanzani
- Chair of Nephrology Vita-Salute University San Raffaele and Genomics of Renal Diseases and Hypertension Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy (L.Z., C.L., S.F., E.M., S.D.C., L.C., M.S., E.B., C.M., P.M.)
| | - Simone Fontana
- Chair of Nephrology Vita-Salute University San Raffaele and Genomics of Renal Diseases and Hypertension Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy (L.Z., C.L., S.F., E.M., S.D.C., L.C., M.S., E.B., C.M., P.M.)
| | - Elisabetta Messaggio
- Chair of Nephrology Vita-Salute University San Raffaele and Genomics of Renal Diseases and Hypertension Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy (L.Z., C.L., S.F., E.M., S.D.C., L.C., M.S., E.B., C.M., P.M.)
| | - Simona Delli Carpini
- Chair of Nephrology Vita-Salute University San Raffaele and Genomics of Renal Diseases and Hypertension Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy (L.Z., C.L., S.F., E.M., S.D.C., L.C., M.S., E.B., C.M., P.M.)
| | - Lorena Citterio
- Chair of Nephrology Vita-Salute University San Raffaele and Genomics of Renal Diseases and Hypertension Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy (L.Z., C.L., S.F., E.M., S.D.C., L.C., M.S., E.B., C.M., P.M.)
| | - Marco Simonini
- Chair of Nephrology Vita-Salute University San Raffaele and Genomics of Renal Diseases and Hypertension Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy (L.Z., C.L., S.F., E.M., S.D.C., L.C., M.S., E.B., C.M., P.M.)
| | - Elena Brioni
- Chair of Nephrology Vita-Salute University San Raffaele and Genomics of Renal Diseases and Hypertension Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy (L.Z., C.L., S.F., E.M., S.D.C., L.C., M.S., E.B., C.M., P.M.)
| | - Cristiano Magnaghi
- Chair of Nephrology Vita-Salute University San Raffaele and Genomics of Renal Diseases and Hypertension Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy (L.Z., C.L., S.F., E.M., S.D.C., L.C., M.S., E.B., C.M., P.M.)
| | - Gualtiero Ivanoe Colombo
- Unit of Immunology and Functional Genomics, IRCCS Centro Cardiologico Monzino, Milan, Italy (G.I.C.)
| | - Giada Santini
- From the Nephrology and Dialysis Complex Operative Unit, ASL Nord Ovest Toscana, Livorno, Italy (R.B., G.S., F.N., F.C., S.B.)
| | - Francesca Nistri
- From the Nephrology and Dialysis Complex Operative Unit, ASL Nord Ovest Toscana, Livorno, Italy (R.B., G.S., F.N., F.C., S.B.)
| | - Filippo Cellai
- From the Nephrology and Dialysis Complex Operative Unit, ASL Nord Ovest Toscana, Livorno, Italy (R.B., G.S., F.N., F.C., S.B.)
| | - Salvatore Lenti
- Hypertension Center, Department of Internal Medicine, San Donato Hospital, USL Sud Est Toscana, Arezzo, Italy (S.L.)
| | - Stefano Bianchi
- From the Nephrology and Dialysis Complex Operative Unit, ASL Nord Ovest Toscana, Livorno, Italy (R.B., G.S., F.N., F.C., S.B.)
| | - Giovanni Battista Pertosa
- Area Livornese Sud, ASL Toscana Nord Ovest, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy (G.B.P., M.T.R., M.P., V.M., L.G.)
| | - Maria Teresa Rocchetti
- Area Livornese Sud, ASL Toscana Nord Ovest, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy (G.B.P., M.T.R., M.P., V.M., L.G.)
| | - Massimo Papale
- Area Livornese Sud, ASL Toscana Nord Ovest, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy (G.B.P., M.T.R., M.P., V.M., L.G.)
| | - Valeria Mezzolla
- Area Livornese Sud, ASL Toscana Nord Ovest, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy (G.B.P., M.T.R., M.P., V.M., L.G.)
| | - Loreto Gesualdo
- Area Livornese Sud, ASL Toscana Nord Ovest, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy (G.B.P., M.T.R., M.P., V.M., L.G.)
| | - Maria Pina Concas
- Institute for Maternal and Child Health, IRCCS Burlo Garofolo, Trieste, Italy (M.P.C.)
| | - Vito Campese
- Division of Nephrology and Hypertension, Keck School of Medicine, University of Southern California, Los Angeles, CA (V.C.)
| | - Paolo Manunta
- Chair of Nephrology Vita-Salute University San Raffaele and Genomics of Renal Diseases and Hypertension Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy (L.Z., C.L., S.F., E.M., S.D.C., L.C., M.S., E.B., C.M., P.M.)
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A Review on Adducin from Functional to Pathological Mechanisms: Future Direction in Cancer. BIOMED RESEARCH INTERNATIONAL 2018; 2018:3465929. [PMID: 29862265 PMCID: PMC5976920 DOI: 10.1155/2018/3465929] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/03/2018] [Accepted: 04/04/2018] [Indexed: 12/14/2022]
Abstract
Adducin (ADD) is a family of membrane skeleton proteins including ADD1, ADD2, and ADD3 that are encoded by distinct genes on different chromosomes. Adducin is primarily responsible for the assembly of spectrin-actin network that provides physical support to the plasma membrane and mediates signal transduction in various cellular physiological processes upon regulation by protein kinase C-dependent and calcium/calmodulin-dependent pathways. Abnormal phosphorylation, genetic variations, and alternative splicing of adducin may contribute to alterations in cellular functions involved in pathogenic processes. These alterations are associated with a wide range of diseases including cancer. This paper begins with a discussion on how adducin partakes in the structural formation of membrane skeleton, its regulation, and related functional characteristics, followed by a review on the pathogenesis of hypertension, biliary atresia, and cancer with respect to increased disease susceptibility mediated by adducin polymorphism and/or dysregulation. Given the functional diversity of adducin in different cellular compartments, we aim to provide a knowledge base whereby its pathophysiological roles can be better understood. More importantly, we aim to provide novel insights that may be of significance in turning the adducin model to clinical application.
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7
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Padmanabhan S, Joe B. Towards Precision Medicine for Hypertension: A Review of Genomic, Epigenomic, and Microbiomic Effects on Blood Pressure in Experimental Rat Models and Humans. Physiol Rev 2017; 97:1469-1528. [PMID: 28931564 PMCID: PMC6347103 DOI: 10.1152/physrev.00035.2016] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 04/28/2017] [Accepted: 04/29/2017] [Indexed: 12/11/2022] Open
Abstract
Compelling evidence for the inherited nature of essential hypertension has led to extensive research in rats and humans. Rats have served as the primary model for research on the genetics of hypertension resulting in identification of genomic regions that are causally associated with hypertension. In more recent times, genome-wide studies in humans have also begun to improve our understanding of the inheritance of polygenic forms of hypertension. Based on the chronological progression of research into the genetics of hypertension as the "structural backbone," this review catalogs and discusses the rat and human genetic elements mapped and implicated in blood pressure regulation. Furthermore, the knowledge gained from these genetic studies that provide evidence to suggest that much of the genetic influence on hypertension residing within noncoding elements of our DNA and operating through pervasive epistasis or gene-gene interactions is highlighted. Lastly, perspectives on current thinking that the more complex "triad" of the genome, epigenome, and the microbiome operating to influence the inheritance of hypertension, is documented. Overall, the collective knowledge gained from rats and humans is disappointing in the sense that major hypertension-causing genes as targets for clinical management of essential hypertension may not be a clinical reality. On the other hand, the realization that the polygenic nature of hypertension prevents any single locus from being a relevant clinical target for all humans directs future studies on the genetics of hypertension towards an individualized genomic approach.
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Affiliation(s)
- Sandosh Padmanabhan
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom; and Center for Hypertension and Personalized Medicine; Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio
| | - Bina Joe
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom; and Center for Hypertension and Personalized Medicine; Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio
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8
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Fan F, Pabbidi MR, Ge Y, Li L, Wang S, Mims PN, Roman RJ. Knockdown of Add3 impairs the myogenic response of renal afferent arterioles and middle cerebral arteries. Am J Physiol Renal Physiol 2016; 312:F971-F981. [PMID: 27927653 PMCID: PMC5495887 DOI: 10.1152/ajprenal.00529.2016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 11/29/2016] [Accepted: 12/05/2016] [Indexed: 11/22/2022] Open
Abstract
We have reported that the myogenic response of the renal afferent arteriole (Af-art) and middle cerebral artery (MCA) and autoregulation of renal and cerebral blood flow are impaired in Fawn-Hooded Hypertensive (FHH) rats. Transfer of a region of chromosome 1 containing γ-adducin (Add3) from the Brown Norway rat rescued the vascular dysfunction and the development of renal disease. To examine whether Add3 is a viable candidate gene altering renal and cerebral hemodynamics in FHH rats, we knocked down the expression of Add3 in rat Af-arts and MCAs cultured for 36-h using a 27-mer Dicer-substrate short interfering RNA (DsiRNA). Control Af-arts constricted by 10 ± 1% in response to an elevation in pressure from 60 to 120 mmHg but dilated by 4 ± 3% when treated with Add3 DsiRNA. Add3 DsiRNA had no effect on the vasoconstrictor response of the Af-art to norepinephrine (10-7 M). Add3 DsiRNA had a similar effect on the attenuation of the myogenic response in the MCA. Peak potassium currents were threefold higher in smooth muscle cells isolated from Af-arts or MCAs transfected with Add3 DsiRNA than in nontransfected cells isolated from the same vessels. This is the first study demonstrating that Add3 plays a role in the regulation of potassium channel function and vascular reactivity. It supports the hypothesis that sequence variants in Add3, which we previously identified in FHH rats, may play a causal role in the impaired myogenic response and autoregulation in the renal and cerebral circulation.
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Affiliation(s)
- Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Mallikarjuna R Pabbidi
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Ying Ge
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Longyang Li
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Shaoxun Wang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Paige N Mims
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
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Ouabain Contributes to Kidney Damage in a Rat Model of Renal Ischemia-Reperfusion Injury. Int J Mol Sci 2016; 17:ijms17101728. [PMID: 27754425 PMCID: PMC5085759 DOI: 10.3390/ijms17101728] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 10/06/2016] [Accepted: 10/10/2016] [Indexed: 01/19/2023] Open
Abstract
Warm renal ischemia performed during partial nephrectomy has been found to be associated with kidney disease. Since endogenous ouabain (EO) is a neuro-endocrine hormone involved in renal damage, we evaluated the role of EO in renal ischemia-reperfusion injury (IRI). We measured plasma and renal EO variations and markers of glomerular and tubular damage (nephrin, KIM-1, Kidney-Injury-Molecule-1, α1 Na-K ATPase) and the protective effect of the ouabain inhibitor, rostafuroxin. We studied five groups of rats: (1) normal; (2) infused for eight weeks with ouabain (30 µg/kg/day, OHR) or (3) saline; (4) ouabain; or (5) saline-infused rats orally treated with 100 µg/kg/day rostafuroxin for four weeks. In group 1, 2-3 h after IRI, EO increased in ischemic kidneys while decreased in plasma. Nephrin progressively decreased and KIM-1 mRNA increased starting from 24 h. Ouabain infusion (group 2) increased blood pressure (from 111.7 to 153.4 mmHg) and ouabain levels in plasma and kidneys. In OHR ischemic kidneys at 120 h from IRI, nephrin, and KIM-1 changes were greater than those detected in the controls infused with saline (group 3). All these changes were blunted by rostafuroxin treatment (groups 4 and 5). These findings support the role of EO in IRI and suggest that rostafuroxin pre-treatment of patients before partial nephrectomy with warm ischemia may reduce IRI, particularly in those with high EO.
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Galletti F, Strazzullo P. The blood pressure-salt sensitivity paradigm: pathophysiologically sound yet of no practical value. Nephrol Dial Transplant 2016; 31:1386-91. [PMID: 27521374 DOI: 10.1093/ndt/gfw295] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 06/21/2016] [Indexed: 01/12/2023] Open
Abstract
Sodium plays an important pathophysiological role in blood pressure (BP) values and in the development of hypertension, and epidemiological studies such as the Intersalt Study have shown that the increase in BP occurring with age is determined by salt intake. Recently, a meta-analysis of 13 prospective studies has also shown the close relationship between excess sodium intake and higher risk of stroke and total cardiovascular events. However, the BP response to changing salt intake displayed a marked variability, as first suggested by Kawasaki et al. (The effect of high-sodium and low-sodium intakes on blood pressure and other related variables in human subjects with idiopathic hypertension. Am J Med 1978; 64: 193-198) and later by Weinberger et al. (Definitions and characteristics of sodium sensitivity and blood pressure resistance. Hypertension 1986; 8: II127-II134), who recognized the heterogeneity of the BP response to salt and developed the concept of salt sensitivity. We have a large body of evidence in favour of a major role of metabolic and neuro-hormonal factors in determining BP salt sensitivity in association with the effect of genetic variation. There is evidence that salt sensitivity influences the development of organ damage, even independently-at least in part-of BP levels and the occurrence of hypertension. In addition, several observational studies indicate that salt sensitivity is clearly associated with a higher rate of cardiovascular events and mortality, independently of BP levels and hypertension. A cluster of factors with well-known atherogenic potential such as hyperinsulinaemia, dyslipidaemia and microalbuminuria-all known to be prevalent in salt-sensitive hypertension-might at least partially explain the increased cardiovascular risk observed in salt sensitive individuals. The gold standard for the evaluation of BP salt sensitivity is the BP response to a moderate reduction of salt intake for several weeks; nevertheless, these protocols often suffer of poor patient compliance to dietary instructions. To overcome this problem, short-term tests have been proposed that evaluate either large differences in salt intake for a few days or the response to intravenous administration of saline solution and short-acting diuretics. Recently, the use of ambulatory BP measurement has been proposed for the clinical assessment of BP salt sensitivity. Noteworthy, BP salt sensitivity, in whomever or however assessed, behaves as a continuous variable but salt sensitivity is used as a categorical parameter, with salt-sensitive individuals being defined as those with a difference in BP between low- and high-sodium intake >10%, and salt-resistant subjects those in whom BP does not increase or shows an increase <5% under sodium loading. The general conclusion that can and should be drawn from the above considerations is that the paradigm of salt sensitivity, despite its important pathophysiological meaning, is not helpful, so far, to the practising physician in clinical practice nor is it relevant or useful to the design and implementation of a population-based strategy of salt intake reduction; however, further studies are warranted for an accurate assessment of the salt-sensitivity phenotype in clinical practice. In the absence of a population strategy for salt intake reduction, the aim should be the generation of a 'low sodium environment' allowing for a dietary salt intake tailored on true human requirements and not on deleterious lifestyle habits.
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Affiliation(s)
- Ferruccio Galletti
- Department of Clinical Medicine and Surgery, Excellence Center of Hypertension, 'Federico II' University of Naples Medical School, Naples, Italy
| | - Pasquale Strazzullo
- Department of Clinical Medicine and Surgery, Excellence Center of Hypertension, 'Federico II' University of Naples Medical School, Naples, Italy
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11
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Abstract
During the past 20 years, the studies on genetics or pharmacogenomics of primary hypertension provided interesting results supporting the role of genetics, but no actionable finding ready to be translated into personalized medicine. Two types of approaches have been applied: a "hypothesis-driven" approach on the candidate genes, coding for proteins involved in the biochemical machinery underlying the regulation of BP, and an "unbiased hypothesis-free" approach with GWAS, based on the randomness principles of frequentist statistics. During the past 10-15 years, the application of the latter has overtaken the application of the former leading to an enlargement of the number of previously unknown candidate loci or genes but without any actionable result for the therapy of hypertension. In the present review, we summarize the results of our hypothesis-driven approach based on studies carried out in rats with genetic hypertension and in humans with essential hypertension at the pre-hypertensive and early hypertensive stages. These studies led to the identification of mutant adducin and endogenous ouabain as candidate genetic-molecular mechanisms in both species. Rostafuroxin has been developed for its ability to selectively correct Na(+) pump abnormalities sustained by the two abovementioned mechanisms and to selectively reduce BP in rats and in humans carrying the gene variants underlying the mutant adducin and endogenous ouabain (EO) effects. A clinical trial is ongoing to substantiate these findings. Future studies should apply both the candidate gene and GWAS approaches to fully exploit the potential of genetics in optimizing the personalized therapy.
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12
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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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13
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Identification of adducin-binding residues on the cytoplasmic domain of erythrocyte membrane protein, band 3. Biochem J 2016; 473:3147-58. [PMID: 27435097 DOI: 10.1042/bcj20160328] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/19/2016] [Indexed: 12/26/2022]
Abstract
Two major complexes form structural bridges that connect the erythrocyte membrane to its underlying spectrin-based cytoskeleton. Although the band 3-ankyrin bridge may account for most of the membrane-to-cytoskeleton interactions, the linkage between the cytoplasmic domain of band 3 (cdb3) and adducin has also been shown to be critical to membrane integrity. In the present paper, we demonstrate that adducin, a major component of the spectrin-actin junctional complex, binds primarily to residues 246-264 of cdb3, and mutation of two exposed glutamic acid residues within this sequence completely abrogates both α- and β-adducin binding. Because these residues are located next to the ankyrin-binding site on cdb3, it seems unlikely that band 3 can bind ankyrin and adducin concurrently, reducing the chances of an association between the ankyrin and junctional complexes that would significantly compromise erythrocyte membrane integrity. We also demonstrate that adducin binds the kidney isoform of cdb3, a spliceoform that lacks the first 65 amino acids of erythrocyte cdb3, including the central strand of a large β-pleated sheet. Because kidney cdb3 is not known to bind any of the common peripheral protein partners of erythrocyte cdb3, including ankyrin, protein 4.1, glyceraldehyde-3-phosphate dehydrogenase, aldolase, and phosphofructokinase, retention of this affinity for adducin was unexpected.
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Khan MAH, Sharma A, Rarick KR, Roman RJ, Harder DR, Imig JD. Elevated Aminopeptidase P Attenuates Cerebral Arterial Responses to Bradykinin in Fawn-Hooded Hypertensive Rats. PLoS One 2015; 10:e0145335. [PMID: 26683993 PMCID: PMC4686180 DOI: 10.1371/journal.pone.0145335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 12/02/2015] [Indexed: 01/30/2023] Open
Abstract
Cerebral arterial myogenic and autoregulatory responses are impaired in Fawn Hooded hypertensive (FHH) rats. Cerebral autoregulatory responses are restored in the congenic rat strain in which a segment of chromosome 1 from the Brown Norway (BN) rat was transferred into the FHH genetic background (FHH.1BN). The impact of this region on cerebral arterial dilator responses remains unknown. Aminopeptidase is a gene that was transferred into the FHH genetic background to generate the FHH.1BN rats and is responsible for degradation of the vasodilator bradykinin. Thus, we hypothesized that FHH rats will have increased aminopeptidase P levels with impaired cerebral arterial responses to bradykinin compared to BN and FHH.1BN rats. We demonstrated higher cerebral arterial expression of aminopeptidase P in FHH compared to BN rats. Accordingly, we demonstrated markedly impaired cerebral arterial dilation to bradykinin in FHH compared to BN rats. Interestingly, aminopeptidase P expression was lower in FHH.1BN compared to FHH rats. Decreased aminopeptidase P levels in FHH.1BN rats were associated with increased cerebral arterial bradykinin-induced dilator responses. Aminopeptidase P inhibition by apstatin improved cerebral arterial bradykinin dilator responses in FHH rats to a level similar to FHH.1BN rats. Unlike bradykinin, cerebral arterial responses to acetylcholine were similar between FHH and FHH.1BN groups. These findings indicate decreased bradykinin bioavailability contributes to impaired cerebral arterial dilation in FHH rats. Overall, these data indicate an important role of aminopeptidase P in the impaired cerebral arterial function in FHH rat.
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Affiliation(s)
- Md Abdul Hye Khan
- Department of Pharmacology & Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Amit Sharma
- Department of Pharmacology & Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Kevin R. Rarick
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Richard J. Roman
- Department of Pharmacology & Toxicology, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - David R. Harder
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - John D. Imig
- Department of Pharmacology & Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- * E-mail:
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15
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Habitual dietary intake of β-carotene, vitamin C, folate, or vitamin E may interact with single nucleotide polymorphisms on brachial-ankle pulse wave velocity in healthy adults. Eur J Nutr 2015; 55:855-866. [PMID: 25869180 DOI: 10.1007/s00394-015-0896-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 03/30/2015] [Indexed: 12/22/2022]
Abstract
PURPOSE The interaction between genetics and diet may explain the present disagreement in the protective role of vitamin intake on cardiovascular disease. We cross-sectionally assessed the interaction of habitual dietary intake of β-carotene, vitamin C, folate, and vitamin E with single nucleotide polymorphisms (SNPs) on brachial-ankle pulse wave velocity (baPWV), a measure of arterial stiffness. METHODS Dietary intakes of β-carotene, vitamin C, folate, and vitamin E were quantified by a food frequency questionnaire in 3198 healthy men and women (≥ 40 years) from the Korea Multi-Rural communities Cohort study. baPWV was measured, and 19 SNPs were genotyped. The associations and interactions between dietary vitamin intake, SNP genotype, and baPWV were assessed using general linear models. RESULTS In both men and women, dietary intake of β-carotene, vitamin C, folate, or vitamin E and baPWV were not directly associated. Vitamin C, folate, and vitamin E intake had an interaction with rs4961 (ADD1) genotype on baPWV in men. rs4961 also interacted with folate intake on baPWV in women. In women, rs10817542 (ZNF618) and rs719856 (CD2AP) had an interaction with β-carotene and folate intake and rs5443 (GNB3) had an interaction with vitamin E intake on baPWV. In general, minor allele homozygotes with low vitamin intake had higher baPWV than other subgroups. Results were similar when supplement users were excluded. CONCLUSIONS Higher intake of dietary vitamin C, folate, and vitamin E may be related to high baPWV in healthy Korean men who are minor allele homozygotes of rs4961. In healthy Korean women, dietary folate, β-carotene, and vitamin E intake may affect baPWV differently according to rs4961, rs10817542, rs719856, or rs5443 genotype. Greater dietary intake of these nutrients may protect those that are genetically vulnerable to stiffening of the arteries.
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16
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Gallardo G, Barowski J, Ravits J, Siddique T, Lingrel JB, Robertson J, Steen H, Bonni A. An α2-Na/K ATPase/α-adducin complex in astrocytes triggers non-cell autonomous neurodegeneration. Nat Neurosci 2014; 17:1710-9. [PMID: 25344630 DOI: 10.1038/nn.3853] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 09/29/2014] [Indexed: 12/15/2022]
Abstract
Perturbations of astrocytes trigger neurodegeneration in several diseases, but the glial cell-intrinsic mechanisms that induce neurodegeneration remain poorly understood. We found that a protein complex of α2-Na/K ATPase and α-adducin was enriched in astrocytes expressing mutant superoxide dismutase 1 (SOD1), which causes familial amyotrophic lateral sclerosis (ALS). Knockdown of α2-Na/K ATPase or α-adducin in mutant SOD1 astrocytes protected motor neurons from degeneration, including in mutant SOD1 mice in vivo. Heterozygous disruption of the α2-Na/K ATPase gene suppressed degeneration in vivo and increased the lifespan of mutant SOD1 mice. The pharmacological agent digoxin, which inhibits Na/K ATPase activity, protected motor neurons from mutant SOD1 astrocyte-induced degeneration. Notably, α2-Na/K ATPase and α-adducin were upregulated in spinal cord of sporadic and familial ALS patients. Collectively, our findings define chronic activation of the α2-Na/K ATPase/α-adducin complex as a critical glial cell-intrinsic mechanism of non-cell autonomous neurodegeneration, with implications for potential therapies for neurodegenerative diseases.
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Affiliation(s)
- Gilbert Gallardo
- 1] Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA. [2] Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jessica Barowski
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - John Ravits
- Department of Neurosciences, University of California, San Diego, La Jolla, California, USA
| | - Teepu Siddique
- 1] Department of Neurology, Northwestern Feinberg School of Medicine, Chicago, Illinois, USA. [2] Department of Molecular and Cellular Biology, Northwestern Feinberg School of Medicine, Chicago, Illinois, USA
| | - Jerry B Lingrel
- Department of Molecular Genetics, Biochemistry and Microbiology, College of Medicine, University of Cincinnati, Cincinnati, Ohio, USA
| | - Janice Robertson
- Tanz Centre for Research in Neurodegenerative Diseases and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Hanno Steen
- Department of Pathology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Azad Bonni
- 1] Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA. [2] Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri, USA
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17
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Li G, Flodby P, Luo J, Kage H, Sipos A, Gao D, Ji Y, Beard LL, Marconett CN, DeMaio L, Kim YH, Kim KJ, Laird-Offringa IA, Minoo P, Liebler JM, Zhou B, Crandall ED, Borok Z. Knockout mice reveal key roles for claudin 18 in alveolar barrier properties and fluid homeostasis. Am J Respir Cell Mol Biol 2014; 51:210-22. [PMID: 24588076 DOI: 10.1165/rcmb.2013-0353oc] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Claudin proteins are major constituents of epithelial and endothelial tight junctions (TJs) that regulate paracellular permeability to ions and solutes. Claudin 18, a member of the large claudin family, is highly expressed in lung alveolar epithelium. To elucidate the role of claudin 18 in alveolar epithelial barrier function, we generated claudin 18 knockout (C18 KO) mice. C18 KO mice exhibited increased solute permeability and alveolar fluid clearance (AFC) compared with wild-type control mice. Increased AFC in C18 KO mice was associated with increased β-adrenergic receptor signaling together with activation of cystic fibrosis transmembrane conductance regulator, higher epithelial sodium channel, and Na-K-ATPase (Na pump) activity and increased Na-K-ATPase β1 subunit expression. Consistent with in vivo findings, C18 KO alveolar epithelial cell (AEC) monolayers exhibited lower transepithelial electrical resistance and increased solute and ion permeability with unchanged ion selectivity. Claudin 3 and claudin 4 expression was markedly increased in C18 KO mice, whereas claudin 5 expression was unchanged and occludin significantly decreased. Microarray analysis revealed changes in cytoskeleton-associated gene expression in C18 KO mice, consistent with observed F-actin cytoskeletal rearrangement in AEC monolayers. These findings demonstrate a crucial nonredundant role for claudin 18 in the regulation of alveolar epithelial TJ composition and permeability properties. Increased AFC in C18 KO mice identifies a role for claudin 18 in alveolar fluid homeostasis beyond its direct contributions to barrier properties that may, at least in part, compensate for increased permeability.
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Affiliation(s)
- Guanglei Li
- 1 Will Rogers Institute Pulmonary Research Center, Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine
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18
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Popov S, Takemori H, Tokudome T, Mao Y, Otani K, Mochizuki N, Pires N, Pinho MJ, Franco-Cereceda A, Torielli L, Ferrandi M, Hamsten A, Soares-da-Silva P, Eriksson P, Bertorello AM, Brion L. Lack of salt-inducible kinase 2 (SIK2) prevents the development of cardiac hypertrophy in response to chronic high-salt intake. PLoS One 2014; 9:e95771. [PMID: 24752134 PMCID: PMC3994160 DOI: 10.1371/journal.pone.0095771] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 03/28/2014] [Indexed: 01/01/2023] Open
Abstract
Cardiac left ventricle hypertrophy (LVH) constitutes a major risk factor for heart failure. Although LVH is most commonly caused by chronic elevation in arterial blood pressure, reduction of blood pressure to normal levels does not always result in regression of LVH, suggesting that additional factors contribute to the development of this pathology. We tested whether genetic preconditions associated with the imbalance in sodium homeostasis could trigger the development of LVH without concomitant increases in blood pressure. The results showed that the presence of a hypertensive variant of α-adducin gene in Milan rats (before they become hypertensive) resulted in elevated expression of genes associated with LVH, and of salt-inducible kinase 2 (SIK2) in the left ventricle (LV). Moreover, the mRNA expression levels of SIK2, α-adducin, and several markers of cardiac hypertrophy were positively correlated in tissue biopsies obtained from human hearts. In addition, we found in cardiac myocytes that α-adducin regulates the expression of SIK2, which in turn mediates the effects of adducin on hypertrophy markers gene activation. Furthermore, evidence that SIK2 is critical for the development of LVH in response to chronic high salt diet (HS) was obtained in mice with ablation of the sik2 gene. Increases in the expression of genes associated with LVH, as well as increases in LV wall thickness upon HS, occurred only in sik2+/+ but not in sik2−/− mice. Thus LVH triggered by HS or the presence of a genetic variant of α-adducin requires SIK2 and is independent of elevated blood pressure. Inhibitors of SIK2 may constitute part of a novel therapeutic regimen aimed at prevention/regression of LVH.
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Affiliation(s)
- Sergej Popov
- Membrane Signaling Networks, Department of Medicine, Karolinska Institutet, CMM, Karolinska University Hospital-Solna, Stockholm, Sweden
| | - Hiroshi Takemori
- Laboratory of Cell Signaling and Metabolism, National Institute for Biomedical Innovation, Osaka, Japan
| | - Takeshi Tokudome
- Department of Biochemistry, National Cerebral and Cardiovascular Research Institute, Osaka, Japan
| | - Yuanjie Mao
- Department of Biochemistry, National Cerebral and Cardiovascular Research Institute, Osaka, Japan
| | - Kentaro Otani
- Regenerative Medicine and Tissue Engineering, National Cerebral and Cardiovascular Research Institute, Osaka, Japan
| | - Naoki Mochizuki
- Cell Biology, National Cerebral and Cardiovascular Research Institute, Osaka, Japan
| | - Nuno Pires
- BIAL - Portela & C, S.A., S. Mamede do Coronado, Portugal
| | - Maria João Pinho
- MedInUP - Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
| | - Anders Franco-Cereceda
- Cardiothoracic Surgery Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Lucia Torielli
- Prassis Sigma-Tau Research Institute, Settimo Milanese, Milan, Italy
| | - Mara Ferrandi
- Prassis Sigma-Tau Research Institute, Settimo Milanese, Milan, Italy
| | - Anders Hamsten
- Cardiovascular Genetics and Genomics, Department of Medicine, Karolinska Institutet, CMM, Karolinska University Hospital-Solna, Stockholm, Sweden
| | - Patricio Soares-da-Silva
- BIAL - Portela & C, S.A., S. Mamede do Coronado, Portugal
- MedInUP - Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
| | - Per Eriksson
- Cardiovascular Genetics and Genomics, Department of Medicine, Karolinska Institutet, CMM, Karolinska University Hospital-Solna, Stockholm, Sweden
| | - Alejandro M. Bertorello
- Membrane Signaling Networks, Department of Medicine, Karolinska Institutet, CMM, Karolinska University Hospital-Solna, Stockholm, Sweden
| | - Laura Brion
- Membrane Signaling Networks, Department of Medicine, Karolinska Institutet, CMM, Karolinska University Hospital-Solna, Stockholm, Sweden
- * E-mail:
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20
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Lecuona E, Sun H, Chen J, Trejo HE, Baker MA, Sznajder JI. Protein kinase A-Iα regulates Na,K-ATPase endocytosis in alveolar epithelial cells exposed to high CO(2) concentrations. Am J Respir Cell Mol Biol 2013; 48:626-34. [PMID: 23349050 DOI: 10.1165/rcmb.2012-0373oc] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Elevated concentrations of CO2 (hypercapnia) lead to alveolar epithelial dysfunction by promoting Na,K-ATPase endocytosis. In the present report, we investigated whether the CO2/HCO3(-) activated soluble adenylyl cyclase (sAC) regulates this process. We found that hypercapnia increased the production of cyclic adenosine monophosphate (cAMP) and stimulated protein kinase A (PKA) activity via sAC, which was necessary for Na,K-ATPase endocytosis. During hypercapnia, cAMP was mainly produced in specific microdomains in the proximity of the plasma membrane, leading to PKA Type Iα activation. In alveolar epithelial cells exposed to high CO2 concentrations, PKA Type Iα regulated the time-dependent phosphorylation of the actin cytoskeleton component α-adducin at serine 726. Cells expressing small hairpin RNA for PKAc, dominant-negative PKA Type Iα, small interfering RNA for α-adducin, and α-adducin with serine 726 mutated to alanine prevented Na,K-ATPase endocytosis. In conclusion, we provide evidence for a new mechanism by which hypercapnia via sAC, cAMP, PKA Type Iα, and α-adducin regulates Na,K-ATPase endocytosis in alveolar epithelial cells.
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Affiliation(s)
- Emilia Lecuona
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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21
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Mondini A, Sassone F, Civello DA, Garavaglia ML, Bazzini C, Rodighiero S, Vezzoli V, Conti F, Torielli L, Capasso G, Paulmichl M, Meyer G. Hypertension-linked mutation of α-adducin increases CFTR surface expression and activity in HEK and cultured rat distal convoluted tubule cells. PLoS One 2012; 7:e52014. [PMID: 23284854 PMCID: PMC3528715 DOI: 10.1371/journal.pone.0052014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 11/08/2012] [Indexed: 11/18/2022] Open
Abstract
The CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) activity and localization are influenced by the cytoskeleton, in particular by actin and its polymerization state. In this study we investigated whether the expression of the hypertensive mutations of α-adducin (G460W-S586C in humans, F316Y in rats), an actin capping protein, led to a functional modification of CFTR activity and surface expression. The experiments were performed on HEK293 T cells cotransfected with CFTR and the human wild type (WT) or G460W mutated α-adducin. In whole-cell patch-clamp experiments, both the CFTR chloride current and the slope of current activation after forskolin addition were significantly higher in HEK cells overexpressing the G460W adducin. A higher plasma membrane density of active CFTR channels was confirmed by cell-attached patch-clamp experiments, both in HEK cells and in cultured primary DCT cells, isolated from MHS (Milan Hypertensive Strain, a Wistar rat (Rattus norvegicus) hypertensive model carrying the F316Y adducin mutation), compared to MNS (Milan Normotensive Strain) rats. Western blot experiments demonstrated an increase of the plasma membrane CFTR protein expression, with a modification of the channel glycosylation state, in the presence of the mutated adducin. A higher retention of CFTR protein in the plasma membrane was confirmed both by FRAP (Fluorescence Recovery After Photobleaching) and photoactivation experiments. The present data indicate that in HEK cells and in isolated DCT cells the presence of the G460W-S586C hypertensive variant of adducin increases CFTR channel activity, possibly by altering its membrane turnover and inducing a retention of the channel in the plasmamembrane. Since CFTR is known to modulate the activity of many others transport systems, the increased surface expression of the channel could have consequences on the whole network of transport in kidney cells.
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Affiliation(s)
- Anna Mondini
- Department of Life Sciences, Università degli Studi di Milano, Milano, Italy
| | - Francesca Sassone
- Department of Life Sciences, Università degli Studi di Milano, Milano, Italy
| | | | | | - Claudia Bazzini
- Department of Life Sciences, Università degli Studi di Milano, Milano, Italy
| | | | - Valeria Vezzoli
- Department of Life Sciences, Università degli Studi di Milano, Milano, Italy
| | - Fabio Conti
- Prassis Research Institute, Sigma Tau, Settimo M.se, Italy
| | - Lucia Torielli
- Prassis Research Institute, Sigma Tau, Settimo M.se, Italy
| | | | - Markus Paulmichl
- Institut of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
| | - Giuliano Meyer
- Department of Life Sciences, Università degli Studi di Milano, Milano, Italy
- * E-mail:
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Pabbidi MR, Juncos J, Juncos L, Renic M, Tullos HJ, Lazar J, Jacob HJ, Harder DR, Roman RJ. Identification of a region of rat chromosome 1 that impairs the myogenic response and autoregulation of cerebral blood flow in fawn-hooded hypertensive rats. Am J Physiol Heart Circ Physiol 2012; 304:H311-7. [PMID: 23144316 DOI: 10.1152/ajpheart.00622.2012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study examined the effects of transfer of a 2.4-Mbp region of rat chromosome 1 (RNO1) from Brown Norway (BN) into fawn-hooded hypertensive (FHH) rats on autoregulation (AR) of cerebral blood flow (CBF) and the myogenic response of middle cerebral arteries (MCAs). AR of CBF was poor in FHH and FHH.1(BN) AR(-) congenic strains that excluded the critical 2.4-Mbp region. In contrast, AR was restored in FHH.1(BN) AR(+) congenic strains that included this region. The diameter of MCAs of FHH rats increased from 140 ± 14 to 157 ± 18 μm when transmural pressure was increased from 40 to 140 mmHg, but it decreased from 137 ± 5 to 94 ± 7 μm in FHH.1(BN) AR(+) congenic strains. Transient occlusion of MCAs reduced CBF by 80% in all strains. However, the hyperemic response following ischemia was significantly greater in FHH and AR(-) rats than that seen in AR(+) congenic strains (AR(-), 173 ± 11% vs. AR(+), 124 ± 5%). Infarct size and edema formation were also significantly greater in an AR(-) strain (38.6 ± 2.6 and 12.1 ± 2%) than in AR(+) congenic strains (27.6 ± 1.8 and 6.5 ± 0.9%). These results indicate that there is a gene in the 2.4-Mbp region of RNO1 that alters the development of myogenic tone in cerebral arteries. Transfer of this region from BN to FHH rats restores AR of CBF and vascular reactivity and reduces cerebral injury after transient occlusion and reperfusion of the MCA.
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Carmosino M, Procino G, Svelto M. Na+-K+-2Cl- cotransporter type 2 trafficking and activity: the role of interacting proteins. Biol Cell 2012; 104:201-12. [PMID: 22211456 DOI: 10.1111/boc.201100049] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 12/28/2011] [Indexed: 11/30/2022]
Abstract
The central role of Na+-K+-2Cl- cotransporter type 2 (NKCC2) in vectorial transepithelial salt reabsorption in thick ascending limb cells from Henle's loop in the kidney is evidenced by the effects of loop diuretics, the pharmacological inhibitors of NKCC2, that are amongst the most powerful antihypertensive drugs available to date. Moreover, genetic mutations of the NKCC2 encoding gene resulting in impaired apical targeting and function of NKCC2 transporter give rise to a pathological phenotype known as type I Bartter syndrome, characterised by a severe volume depletion, hypokalaemia and metabolic alkalosis with high prenatal mortality. On the contrary, excessive NKCC2 activity has been linked with inherited hypertension in humans and in rodent models. Interestingly, in animal models of hypertension, NKCC2 upregulation is achieved by post-translational mechanisms underlining the need to analyse the molecular mechanisms involved in the regulation of NKCC2 trafficking and activity to gain insights in the pathogenesis of hypertension.
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Affiliation(s)
- Monica Carmosino
- Department of Biosciences, Biotechnologies and Pharmacological Sciences, University of Bari, Bari, Italy.
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New Insights into the Regulation of Na+,K+-ATPase by Ouabain. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 294:99-132. [DOI: 10.1016/b978-0-12-394305-7.00002-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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25
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Linde CI, Karashima E, Raina H, Zulian A, Wier WG, Hamlyn JM, Ferrari P, Blaustein MP, Golovina VA. Increased arterial smooth muscle Ca2+ signaling, vasoconstriction, and myogenic reactivity in Milan hypertensive rats. Am J Physiol Heart Circ Physiol 2011; 302:H611-20. [PMID: 22140038 DOI: 10.1152/ajpheart.00950.2011] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Milan hypertensive strain (MHS) rats are a genetic model of hypertension with adducin gene polymorphisms linked to enhanced renal tubular Na(+) reabsorption. Recently we demonstrated that Ca(2+) signaling is augmented in freshly isolated mesenteric artery myocytes from MHS rats. This is associated with greatly enhanced expression of Na(+)/Ca(2+) exchanger-1 (NCX1), C-type transient receptor potential (TRPC6) protein, and sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2) compared with arteries from Milan normotensive strain (MNS) rats. Here, we test the hypothesis that the enhanced Ca(2+) signaling in MHS arterial smooth muscle is directly reflected in augmented vasoconstriction [myogenic and phenylephrine (PE)-evoked responses] in isolated mesenteric small arteries. Systolic blood pressure was higher in MHS (145 ± 1 mmHg) than in MNS (112 ± 1 mmHg; P < 0.001; n = 16 each) rats. Pressurized mesenteric resistance arteries from MHS rats had significantly augmented myogenic tone and reactivity and enhanced constriction to low-dose (1-100 nM) PE. Isolated MHS arterial myocytes exhibited approximately twofold increased peak Ca(2+) signals in response to 5 μM PE or ATP in the absence and presence of extracellular Ca(2+). These augmented responses are consistent with increased vasoconstrictor-evoked sarcoplasmic reticulum (SR) Ca(2+) release and increased Ca(2+) entry, respectively. The increased SR Ca(2+) release correlates with a doubling of inositol 1,4,5-trisphosphate receptor type 1 and tripling of SERCA2 expression. Pressurized MHS arteries also exhibited a ∼70% increase in 100 nM ouabain-induced vasoconstriction compared with MNS arteries. These functional alterations reveal that, in a genetic model of hypertension linked to renal dysfunction, multiple mechanisms within the arterial myocytes contribute to enhanced Ca(2+) signaling and myogenic and vasoconstrictor-induced arterial constriction. MHS rats have elevated plasma levels of endogenous ouabain, which may initiate the protein upregulation and enhanced Ca(2+) signaling. These molecular and functional changes provide a mechanism for the increased peripheral vascular resistance (whole body autoregulation) that underlies the sustained hypertension.
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Affiliation(s)
- Cristina I Linde
- Dept. of Physiology, Univ. of Maryland School of Medicine, 685 W. Baltimore St. HSF1, Rm. 565, Baltimore, MD 21201, USA
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Silva E, Soares-da-Silva P. Long-term regulation of Na+,K+-ATPase in opossum kidney cells by ouabain. J Cell Physiol 2011; 226:2391-7. [PMID: 21660962 DOI: 10.1002/jcp.22575] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Na(+),K(+)-ATPase, a basolateral transporter responsible for tubular reabsorption of Na(+) and for providing the driving force for vectorial transport of various solutes and ions, can also act as a signal transducer in response to the interaction with steroid hormones. At nanomolar concentrations ouabain binding to Na(+),K(+)-ATPase activates a signaling cascade that ultimately regulates several membrane transporters including Na(+),K(+)-ATPase. The present study evaluated the long-term effect of ouabain on Na(+),K(+)-ATPase activity (Na(+) transepithelial flux) and expression in opossum kidney (OK) cells with low (40) and high (80) number of passages in culture, which are known to overexpress Na(+),K(+)-ATPase (Silva et al., 2006, J Membr Biol 212, 163-175). Activation of a signal cascade was evaluated by quantification of ERK1/2 phosphorylation by Western blot. Na(+),K(+)-ATPase activity was determined by electrophysiological techniques and expression by Western blot. Incubation of cells with ouabain induced activation of ERK1/2. Long-term incubation with ouabain induced an increase in Na(+) transepithelial flux and Na(+),K(+)-ATPase expression only in OK cells with 80 passages in culture. This increase was prevented by incubation with inhibitors of MEK1/2 and PI-3K. In conclusion, ouabain-activated signaling cascade mediated by both MEK1/2 and PI-3K is responsible for long-term regulation of Na(+) transepithelial flux in epithelial renal cells. OK cell line with high number of passages is suggested to constitute a particular useful model for the understanding of ouabain-mediated regulation of Na(+) transport.
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Affiliation(s)
- E Silva
- Institute of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, Porto, Portugal
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Bełtowski J. Leptin and the Regulation of Renal Sodium Handling and Renal Na-Transporting ATPases: Role in the Pathogenesis of Arterial Hypertension. Curr Cardiol Rev 2011; 6:31-40. [PMID: 21286276 PMCID: PMC2845792 DOI: 10.2174/157340310790231644] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 08/03/2009] [Accepted: 08/03/2009] [Indexed: 12/13/2022] Open
Abstract
Leptin, an adipose tissue hormone which regulates food intake, is also involved in the pathogenesis of arterial hypertension. Plasma leptin concentration is increased in obese individuals. Chronic leptin administration or transgenic overexpression increases blood pressure in experimental animals, and some studies indicate that plasma leptin is elevated in hypertensive subjects independently of body weight. Leptin has a dose- and time-dependent effect on urinary sodium excretion. High doses of leptin increase Na(+) excretion in the short run; partially by decreasing renal Na(+),K(+)-ATPase (sodium pump) activity. This effect is mediated by phosphatidylinositol 3-kinase (PI3K) and is impaired in animals with dietary-induced obesity. In contrast to acute, chronic elevation of plasma leptin to the level observed in patients with the metabolic syndrome impairs renal Na(+) excretion, which is associated with the increase in renal Na(+),K(+)-ATPase activity. This effect results from oxidative stress-induced deficiency of nitric oxide and/or transactivation of epidermal growth factor receptor and subsequent stimulation of extracellular signal-regulated kinases. Ameliorating "renal leptin resistance" or reducing leptin level and/or leptin signaling in states of chronic hyperleptinemia may be a novel strategy for the treatment of arterial hypertension associated with the metabolic syndrome.
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Affiliation(s)
- Jerzy Bełtowski
- Dept. of Pathophysiology, Medical University, Lublin, Poland
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Altered expression of renal aquaporins and α-adducin polymorphisms may contribute to the establishment of salt-sensitive hypertension. Am J Hypertens 2011; 24:822-8. [PMID: 21451595 DOI: 10.1038/ajh.2011.47] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Sodium-sensitive hypertension is caused by renal tubular dysfunction, leading to increased retention of sodium and water. Previous findings have suggested that single-nucleotide polymorphisms of the cytoskeletal protein, α-adducin, are associated with increased membrane expression of the Na/K pump and abnormal renal sodium transport in Milan hypertensive strain (MHS) rats and in humans. However, the possible contribution of renal aquaporins (AQPs) to water retention remains undefined in MHS rats. METHODS Kidneys from MHS rats were analyzed and compared with those from age-matched Milan normotensive strain (MNS) animals by quantitative-PCR, immunoblotting, and immunoperoxidase. Endocytosis assay was performed on renal cells stably expressing AQP4 and co-transfected either with wild-type normotensive (NT) or with mutated hypertensive (HT) α-adducin. RESULTS Semiquantitative immunoblotting revealed that AQP1 abundance was significantly decreased only in HT MHS whereas AQP2 was reduced in both young pre-HT and adult-HT animals. On the other hand, AQP4 was dramatically upregulated in MHS regardless of the age. These results were confirmed by immunoperoxidase microscopy. Endocytosis assays clearly showed that the expression of mutated adducin strongly reduced the rate of constitutive AQP4 endocytosis, thereby increasing its abundance at the plasma membrane. CONCLUSIONS We provide here the first evidence that AQP1, AQP2, and AQP4 are dysregulated in the kidneys of MHS animals. In particular, we provide evidence that α-adducin mutations may be responsible for AQP4 upregulation. The downregulation of AQP1 and AQP2 and the upregulation of AQP4 may be relevant for the onset and maintenance of salt-sensitive hypertension.
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Ferrandi M, Molinari I, Torielli L, Padoani G, Salardi S, Rastaldi MP, Ferrari P, Bianchi G. Adducin- and ouabain-related gene variants predict the antihypertensive activity of rostafuroxin, part 1: experimental studies. Sci Transl Med 2011; 2:59ra86. [PMID: 21106940 DOI: 10.1126/scitranslmed.3001815] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Essential hypertension is a complex, multifactorial disease associated with a high cardiovascular risk and whose genetic-molecular basis is heterogeneous and largely unknown. Although multiple antihypertensive therapies are available, the large individual variability in drug response results in only a modest reduction of the cardiovascular risk and unsatisfactory control of blood pressure in the hypertensive population as a whole. Two mechanisms, among others, are associated with essential hypertension and related organ damage: mutant α-adducin variants and high concentrations of endogenous ouabain. An antihypertensive agent, rostafuroxin, selectively inhibits these mechanisms in rodents. We investigated the molecular and functional effects of mutant α-adducin, ouabain, and rostafuroxin in hypertensive rats, human cells, and cell-free systems and demonstrated that both mutant α-adducin variants and the ouabain-Na,K-ATPase (Na(+)- and K(+)-dependent adenosine triphosphatase) complex can interact with the Src-SH2 (Src homology 2) domain, increasing Src activity and the Src-dependent Na,K-ATPase phosphorylation and activity. Wild-type α-adducin or Na,K-ATPase in the absence of ouabain showed no interaction with the Src-SH2 domain. Rostafuroxin disrupted the interactions between the Src-SH2 domain and mutant α-adducin or the ouabain-Na,K-ATPase complex and blunted Src activation and Na,K-ATPase phosphorylation, resulting in blood pressure normalization in the hypertensive rats. We have also shown the translatability of these data to humans in a pharmacogenomic clinical trial, as described in the companion paper.
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Affiliation(s)
- Mara Ferrandi
- Prassis sigma-tau Research Institute, Settimo Milanese, Milan 20019, Italy
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NKCC2 is activated in Milan hypertensive rats contributing to the maintenance of salt-sensitive hypertension. Pflugers Arch 2011; 462:281-91. [DOI: 10.1007/s00424-011-0967-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 04/01/2011] [Accepted: 04/03/2011] [Indexed: 01/11/2023]
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Abstract
The assessment of salt sensitivity of blood pressure is difficult because of the lack of universal consensus on definition. Regardless of the variability in the definition of salt sensitivity, increased salt intake, independent of the actual level of blood pressure, is also a risk factor for cardiovascular morbidity and mortality and kidney disease. A modest reduction in salt intake results in an immediate decrease in blood pressure, with long-term beneficial consequences. However, some have suggested that dietary sodium restriction may not be beneficial to everyone. Thus, there is a need to distinguish salt-sensitive from salt-resistant individuals, but it has been difficult to do so with phenotypic studies. Therefore, there is a need to determine the genes that are involved in salt sensitivity. This review focuses on genes associated with salt sensitivity, with emphasis on the variants associated with salt sensitivity in humans that are not due to monogenic causes. Special emphasis is given to gene variants associated with salt sensitivity whose protein products interfere with cell function and increase blood pressure in transgenic mice.
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Affiliation(s)
- Hironobu Sanada
- Division of Health Science Research, Fukushima Welfare Federation of Agricultural Cooperatives, Fukushima, Japan.
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Citterio L, Lanzani C, Manunta P, Bianchi G. Genetics of primary hypertension: The clinical impact of adducin polymorphisms. Biochim Biophys Acta Mol Basis Dis 2010; 1802:1285-98. [DOI: 10.1016/j.bbadis.2010.03.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 03/26/2010] [Accepted: 03/30/2010] [Indexed: 01/11/2023]
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Zulian A, Baryshnikov SG, Linde CI, Hamlyn JM, Ferrari P, Golovina VA. Upregulation of Na+/Ca2+ exchanger and TRPC6 contributes to abnormal Ca2+ homeostasis in arterial smooth muscle cells from Milan hypertensive rats. Am J Physiol Heart Circ Physiol 2010; 299:H624-33. [PMID: 20622104 DOI: 10.1152/ajpheart.00356.2010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Milan hypertensive strain (MHS) of rats is a model for hypertension in humans. Inherited defects in renal function have been well studied in MHS rats, but the mechanisms that underlie the elevated vascular resistance are unclear. Altered Ca(2+) signaling plays a key role in the vascular dysfunction associated with arterial hypertension. Here we compared Ca(2+) signaling in mesenteric artery smooth muscle cells from MHS rats and its normotensive counterpart (MNS). Systolic blood pressure was higher in MHS than in MNS rats (144 +/- 2 vs. 113 +/- 1 mmHg, P < 0.05). Resting cytosolic free Ca(2+) concentration (measured with fura-2) and ATP-induced Ca(2+) transients were augmented in freshly dissociated arterial myocytes from MHS rats. Ba(2+) entry activated by the diacylglycerol analog 1-oleoyl-2-acetyl-sn-glycerol (a measure of receptor-operated channel activity) was much greater in MHS than MNS arterial myocytes. This correlated with a threefold upregulation of transient receptor potential canonical 6 (TRPC6) protein. TRPC3, the other component of receptor-operated channels, was marginally, but not significantly, upregulated. The expression of TRPC1/5, components of store-operated channels, was not altered in MHS mesenteric artery smooth muscle. Immunoblots also revealed that the Na(+)/Ca(2+) exchanger-1 (NCX1) was greatly upregulated in MHS mesenteric artery (by approximately 13-fold), whereas the expression of plasma membrane Ca(2+)-ATPase was not altered. Ca(2+) entry via the reverse mode of NCX1 evoked by the removal of extracellular Na(+) induced a rapid increase in cytosolic free Ca(2+) concentration that was significantly larger in MHS arterial myocytes. The expression of alpha(1)/alpha(2) Na(+) pumps in MHS mesenteric arteries was not changed. Immunocytochemical observations showed that NCX1 and TRPC6 are clustered in plasma membrane microdomains adjacent to the underlying sarcoplasmic reticulum. In summary, MHS arteries exhibit upregulated TRPC6 and NCX1 and augmented Ca(2+) signaling. We suggest that the increased Ca(2+) signaling contributes to the enhanced vasoconstriction and elevated blood pressure in MHS rats.
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Affiliation(s)
- Alessandra Zulian
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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Giachini FR, Tostes RC. Does Na+ really play a role in Ca2+ homeostasis in hypertension? Am J Physiol Heart Circ Physiol 2010; 299:H602-4. [PMID: 20543080 DOI: 10.1152/ajpheart.00542.2010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Bianchi MG, Gatti R, Torielli L, Padoani G, Gazzola GC, Bussolati O. The glutamate transporter excitatory amino acid carrier 1 associates with the actin-binding protein alpha-adducin. Neuroscience 2010; 169:584-95. [PMID: 20493242 DOI: 10.1016/j.neuroscience.2010.05.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Revised: 04/26/2010] [Accepted: 05/14/2010] [Indexed: 11/28/2022]
Abstract
Excitatory amino acid carrier 1 (EAAC1) belongs to the family of the Na(+)-dependent glutamate carriers. Although the association between defective EAAC1 function and neurologic disease has been repeatedly studied, EAAC1 regulation is not yet fully understood. We have reported that in C6 glioma cells both the activity and membrane targeting of EAAC1 require the integrity of actin cytoskeleton. Here we show that, in the same model, EAAC1 partially co-localizes with actin filaments at the level of cell processes. Moreover, perinuclear spots in which EAAC1 co-localizes with the actin binding protein alpha-adducin are observed in some cells and, consistently, faint co-immunoprecipitation bands between EAAC1 and alpha-adducin are detected. Co-localization and partial co-immunoprecipitation of EAAC1 and adducin are still detectable after cell treatment with phorbol esters, a condition that leads to a protein kinase C (PKC)-dependent increase of EAAC1 expression on the membrane and to the phosphorylation of adducin. A co-immunoprecipitation band was also detected in protein extracts of rat hippocampus. The amount of adducin co-immunoprecipitated with EAAC1 increases after the treatment of C6 cells with retinoic acid, a differentiating agent that induces EAAC1 overexpression in this cell model. Moreover, in clones of C6 cells transfected with a hemagglutinin (HA)-tagged adducin, the bands of EAAC1 immunoprecipitated by an anti-HA antiserum were proportional to EAAC1 expression. These results suggest the existence of a pool of EAAC1 transporters associated with the actin binding protein alpha-adducin in a PKC-insensitive manner.
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Affiliation(s)
- M G Bianchi
- Unit of General and Clinical Pathology, Department of Experimental Medicine, University of Parma, Parma, Italy
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Jaitovich A, Bertorello AM. Intracellular sodium sensing: SIK1 network, hormone action and high blood pressure. Biochim Biophys Acta Mol Basis Dis 2010; 1802:1140-9. [PMID: 20347966 DOI: 10.1016/j.bbadis.2010.03.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 03/12/2010] [Accepted: 03/20/2010] [Indexed: 01/11/2023]
Abstract
Sodium is the main determinant of body fluid distribution. Sodium accumulation causes water retention and, often, high blood pressure. At the cellular level, the concentration and active transport of sodium is handled by the enzyme Na(+),K(+)-ATPase, whose appearance enabled evolving primitive cells to cope with osmotic stress and contributed to the complexity of mammalian organisms. Na(+),K(+)-ATPase is a platform at the hub of many cellular signaling pathways related to sensing intracellular sodium and dealing with its detrimental excess. One of these pathways relies on an intracellular sodium-sensor network with the salt-inducible kinase 1 (SIK1) at its core. When intracellular sodium levels rise, and after the activation of calcium-related signals, this network activates the Na(+),K(+)-ATPase and expel the excess of sodium from the cytosol. The SIK1 network also mediates sodium-independent signals that modulate the activity of the Na(+),K(+)-ATPase, like dopamine and angiotensin, which are relevant per se in the development of high blood pressure. Animal models of high blood pressure, with identified mutations in components of multiple pathways, also have alterations in the SIK1 network. The introduction of some of these mutants into normal cells causes changes in SIK1 activity as well. Some cellular processes related to the metabolic syndrome, such as insulin effects on the kidney and other tissues, also appear to involve the SIK1. Therefore, it is likely that this protein, by modulating active sodium transport and numerous hormonal responses, represents a "crossroad" in the development and adaptation to high blood pressure and associated diseases.
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Affiliation(s)
- Ariel Jaitovich
- Department of Medicine, Karolinska Institutet, Karolinska University Hospital-Solna, 171 76 Stockholm, Sweden.
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Fedorova OV, Shapiro JI, Bagrov AY. Endogenous cardiotonic steroids and salt-sensitive hypertension. Biochim Biophys Acta Mol Basis Dis 2010; 1802:1230-6. [PMID: 20347967 DOI: 10.1016/j.bbadis.2010.03.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Revised: 03/18/2010] [Accepted: 03/20/2010] [Indexed: 12/12/2022]
Abstract
Endogenous cardiotonic steroids (CTS), also called digitalis like factors, have been postulated to play important roles in pathogenesis of hypertension for nearly half of a century. For the past 50 years biomedical scientists have been in quest of an unidentified factor or hormone that both increases blood pressure and renal sodium excretion; this "natriuretic hormone" was, in fact, postulated to interact with the Na/K-ATPase. Recent discoveries have led to the identification of steroid molecules which are present in humans, rodents and amphibians, and which, in a complex manner, interact with each other and with the other systems that regulate renal salt handling and contribute to the salt-sensitivity of blood pressure. Recent findings include the specific identification of endogenous cardenolide (endogenous ouabain) and bufadienolide (marinobufagenin) CTS in humans along with the delineation of mechanisms by which CTS can signal through the Na/K-ATPase. Although CTS were first considered important in the regulation of renal sodium transport and arterial pressure, more recent work implicates these hormones in the central regulation of blood pressure and regulation of cell growth, and development of cardiovascular and renal fibrosis in particular.
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Affiliation(s)
- Olga V Fedorova
- National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
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Taub M, Springate JE, Cutuli F. Targeting of renal proximal tubule Na,K-ATPase by salt-inducible kinase. Biochem Biophys Res Commun 2010; 393:339-44. [PMID: 20152810 DOI: 10.1016/j.bbrc.2010.02.037] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Accepted: 02/06/2010] [Indexed: 11/20/2022]
Abstract
The renal proximal tubule (RPT) is a central locale for Na+ reabsorption, and blood pressure regulation. Na+ reabsorption in the RPT depends upon the Na,K-ATPase, which is controlled by a complex regulatory network, including Salt-Inducible Protein Kinase (SIK). SIKs are recently discovered members of the AMP-activated Protein Kinase (AMPK) family, which regulate salt homeostasis and metabolism in a number of tissues. In the RPT, SIK interacts with the Na,K-ATPase in the basolateral membrane (BM), regulating both the activity and level of Na,K-ATPase in the BM. Thus, Na,K-ATPase activity can be rapidly adjusted in response to changes in Na+ balance. Long-term changes in Na+ intake affect the state of SIK phosphorylation, and as a consequence the phosphorylation of TORCs, Transducers of Regulated CREB (cAMP Regulatory Element Binding Protein). Once phosphorylated, TORCs enter the nucleus, and activate transcription of the ATP1B1 gene encoding for the Na,K-ATPase beta subunit.
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Affiliation(s)
- Mary Taub
- Department of Biochemistry, University at Buffalo, 140 Farber Hall, 3435 Main Street, Buffalo, NY 14214, USA.
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Farina A, Morano D, Arcelli D, De Sanctis P, Sekizawa A, Purwosunu Y, Zucchini C, Simonazzi G, Okai T, Rizzo N. Gene expression in chorionic villous samples at 11 weeks of gestation in women who develop preeclampsia later in pregnancy: implications for screening. Prenat Diagn 2010; 29:1038-44. [PMID: 19731222 DOI: 10.1002/pd.2344] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVES To determine the gene expression profile in chorionic villous samples (CVS) of women destined to develop preeclampsia. METHOD cDNA microarray technology was employed. Ten singleton fetuses of women who subsequently developed preeclampsia where compared with a pool of 50 controls. The mRNA expression of some of the genes previously found to be up- or down-regulated were validated by RT-PCR in peripheral blood from 23 pregnant women at term affected with preeclampsia and 23 controls. RESULTS Altered expression was found among several genes including those involved in invasion of human trophoblasts (Titin), in inflammatory stress (Lactotransferrin), endothelial aberration (Claudin 6), angiogenesis (Vasohibin 1), blood pressure control (Adducin 1). Also the peripheral blood from preeclampsia patients showed significant differences for all the genes studied. CONCLUSION CVS show an aberrant gene profile prior to preeclampsia onset that may be predictive of the disease.
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Affiliation(s)
- Antonio Farina
- Department of Histology, Embryology and Applied Biology, Division of Prenatal Medicine, Via Belmeloro 8, 40126 Bologna, Italy.
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Blocking the salt-inducible kinase 1 network prevents the increases in cell sodium transport caused by a hypertension-linked mutation in human alpha-adducin. J Hypertens 2010; 27:2452-7. [PMID: 19657284 DOI: 10.1097/hjh.0b013e328330cf15] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
OBJECTIVES Because a newly described salt-inducible kinase 1 (SIK1) network is responsible for increases in active cell sodium transport in response to elevated intracellular sodium, we hypothesized that this network could mediate the effects of the mutant (hypertensive) form of alpha-adducin on Na,K-ATPase activity. METHODS Studies were performed in normotensive and hypertensive Milan rats and in a cell line of proximal tubule origin expressing transiently variants of alpha-adducin (human G460W/S586C; rat F316Y) that are associated with elevated blood pressure and result in increased Na,K-ATPase activity. Na,K-ATPase activity was determined as ouabain-sensitive rubidium transport. RESULTS SIK1 activity (T182 phosphorylation) was significantly elevated in renal proximal tubule cells from Milan hypertensive rats (carrying a alpha-adducin mutation) when compared with normotensive controls. Similarly, SIK1 activity (T182 phosphorylation) was elevated in a normal renal proximal tubule cell line when transfected with the alpha-adducin variant carrying the human hypertensive mutation. Blocking the SIK1 network using negative mutants as well as different stages of its activation pathway prevented the effects induced by the hypertensive alpha-adducin. CONCLUSION The SIK1 network may constitute an alternative target by which agents can modulate active sodium transport in renal epithelia and avoid the increases in systemic blood pressure that are associated with genetic mutations in the human alpha-adducin molecule.
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Ferrari P. Rostafuroxin: an ouabain-inhibitor counteracting specific forms of hypertension. Biochim Biophys Acta Mol Basis Dis 2010; 1802:1254-8. [PMID: 20083196 DOI: 10.1016/j.bbadis.2010.01.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 01/08/2010] [Accepted: 01/09/2010] [Indexed: 12/17/2022]
Abstract
An innovative approach to the therapy of essential hypertension (EH) and the related complications has been pursued by our group with the aim of defining specific genetic-molecular mechanisms underlying the disease in sub-sets of patients. This approach is anticipated to have a major effect on the clinical practice, diagnostics and development of new drugs able to selectively target such mechanisms. The final achievement is the definition of biomarkers for identifying patients who more likely should benefit for a given therapy both in terms of efficacy and reduction of the adverse reactions. Among many, two mechanisms have been defined and addressed:Both alterations lead to hypertension, organ hypertrophy, negative vascular remodeling and increased cardiovascular risk by affecting the renal Na(+) handling, through the up-regulation of the Na(+)-K(+) pump and the activation of the Src-dependent signal transduction pathway. A novel antihypertensive agent, rostafuroxin (PST2238), has been selected and developed for its ability to correct the renal Na(+)-K(+) pump abnormalities sustained by the mutant adducin and EO-dependent mechanisms. It is endowed with high potency and efficacy in reducing blood pressure (BP) and preventing organ hypertrophy in animal models representative of both adducin and EO mechanisms. At molecular level, in the kidney, rostafuroxin normalizes the enhanced activity of the Na(+)-K(+) pump induced by mutant adducin and antagonizes the EO triggering of the Src-EGFr-dependent signaling pathway leading to renal Na(+)-K(+) pump and ERK phosphorylation and activation. In the vasculature, it normalizes the increased myogenic tone caused by ouabain. A very high safety ratio and the absence of interaction with other mechanisms involved in BP regulation, together with evidence of high tolerability and efficacy in hypertensive patients indicate rostafuroxin as the first example of a new class of antihypertensive agents designed to antagonize adducin and EO-hypertensive mechanisms. A recently concluded Phase II clinical trial (OASIS) has provided the proof of concept that such a compound is effective in the subset of patients where these two mechanisms are at work.
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Affiliation(s)
- Patrizia Ferrari
- Prassis Research Institute sigma-tau, Settimo M.se, Milan, Italy.
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Seidlerová J. Adducin and its relation to cardiovascular system. Artery Res 2010. [DOI: 10.1016/j.artres.2010.10.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Jaitovich A, Bertorello AM. Salt, Na+,K+-ATPase and hypertension. Life Sci 2009; 86:73-8. [PMID: 19909757 DOI: 10.1016/j.lfs.2009.10.019] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 10/27/2009] [Accepted: 10/30/2009] [Indexed: 12/20/2022]
Abstract
Chronic hypertension is characterized by a persistent increase in vascular tone. Sodium-rich diets promote hypertension; however, the underlying molecular mechanisms are not fully understood. Variations in the sodium content of the diet, through hormonal mediators such as dopamine and angiotensin II, modulate renal tubule Na(+),K(+)-ATPase activity. Stimulation of Na(+),K(+)-ATPase activity increases sodium transport across the renal proximal tubule epithelia, promoting Na(+) retention, whereas inhibited Na(+),K(+)-ATPase activity decreases sodium transport, and thereby natriuresis. Diets rich in sodium also enhance the release of adrenal endogenous ouabain-like compounds (OLC), which inhibit Na(+),K(+)-ATPase activity, resulting in increased intracellular Na(+) and Ca(2+) concentrations in vascular smooth muscle cells, thus increasing the vascular tone, with a corresponding increase in blood pressure. The mechanisms by which these homeostatic processes are integrated in response to salt intake are complex and not completely elucidated. However, recent scientific findings provide new insights that may offer additional avenues to further explore molecular mechanisms related to normal physiology and pathophysiology of various forms of hypertension (i.e. salt-induced). Consequently, new strategies for the development of improved therapeutics and medical management of hypertension are anticipated.
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Affiliation(s)
- Ariel Jaitovich
- Membrane Signaling Networks, Atherosclerosis Research Unit, Department of Medicine, Karolinska Institutet, Karolinska University Hospital-Solna, 171 76 Stockholm, Sweden.
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Gildea JJ, Israel JA, Johnson AK, Zhang J, Jose PA, Felder RA. Caveolin-1 and dopamine-mediated internalization of NaKATPase in human renal proximal tubule cells. Hypertension 2009; 54:1070-6. [PMID: 19752292 DOI: 10.1161/hypertensionaha.109.134338] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In moderate sodium-replete states, dopamine 1-like receptors (D1R/D5R) are responsible for regulating >50% of renal sodium excretion. This is partly mediated by internalization and inactivation of NaKATPase, when associated with adapter protein 2. We used dopaminergic stimulation via fenoldopam (D1-like receptor agonist) to study the interaction among D1-like receptors, caveolin-1 (CAV1), and the G protein-coupled receptor kinase type 4 in cultured human renal proximal tubule cells (RPTCs). We compared 2 groups of RPTCs, 1 of cell lines that were isolated from normal subjects (nRPTCs) and a second group of cell lines that have D1-like receptors that are uncoupled (uncoupled RPTCs) from adenylyl cyclase second messengers. In nRPTCs, fenoldopam increased the plasma membrane expression of D1R (10.0-fold) and CAV1 (1.3-fold) and markedly decreased G protein-coupled receptor kinase type 4 by 94+/-8%; no effects were seen in uncoupled RPTCs. Fenoldopam also increased the association of adapter protein 2 and NaKATPase by 53+/-9% in nRPTCs but not in uncoupled RPTCs. When CAV1 expression was reduced by 86.0+/-8.5% using small interfering RNA, restimulation of the D1-like receptors with fenoldopam in nRPTCs resulted in only a 7+/-9% increase in association between adapter protein 2 and NaKATPase. Basal CAV1 expression and association with G protein-coupled receptor kinase type 4 was decreased in uncoupled RPTCs (58+/-5% decrease in association) relative to nRPTCs. We conclude that the scaffolding protein CAV1 is necessary for the association of D1-like receptors with G protein-coupled receptor kinase type 4 and the adapter protein 2-associated reduction in plasma membrane NaKATPase.
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Affiliation(s)
- John J Gildea
- Department of Pathology, University of Virginia Health System, Charlottesville, VA 22908, USA
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Wang X, Armando I, Upadhyay K, Pascua A, Jose PA. The regulation of proximal tubular salt transport in hypertension: an update. Curr Opin Nephrol Hypertens 2009; 18:412-420. [PMID: 19654544 PMCID: PMC3722593 DOI: 10.1097/mnh.0b013e32832f5775] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE OF REVIEW Renal proximal tubular sodium reabsorption is regulated by sodium transporters, including the sodium glucose transporter, sodium amino acid transporter, sodium hydrogen exchanger isoform 3 and sodium phosphate cotransporter type 2 located at the luminal/apical membrane, and sodium bicarbonate cotransporter and Na+/K+ATPase located at the basolateral membrane. This review summarizes recent studies on sodium transporters that play a major role in the increase in blood pressure in essential/polygenic hypertension. RECENT FINDINGS Sodium transporters and Na+/K+ATPase are segregated in membrane lipid and nonlipid raft microdomains that regulate their activities and trafficking via cytoskeletal proteins. The increase in renal proximal tubule ion transport in polygenic hypertension is primarily due to increased activity of NHE3 and Cl/HCO3 exchanger at the luminal/apical membrane and a primary or secondary increase in Na+/K+ATPase activity. SUMMARY The increase in renal proximal tubule ion transport in hypertension is due to increased actions by prohypertensive factors that are unopposed by antihypertensive factors.
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Affiliation(s)
- Xiaoyan Wang
- Center for Molecular Physiology Research, Children's Research Institute, Children's National Medical Center, Washington, District of Columbia, USA
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Chen Z, Leibiger I, Katz AI, Bertorello AM. Pals-associated tight junction protein functionally links dopamine and angiotensin II to the regulation of sodium transport in renal epithelial cells. Br J Pharmacol 2009; 158:486-93. [PMID: 19563532 DOI: 10.1111/j.1476-5381.2009.00299.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND AND PURPOSE Dopamine inhibits renal cell Na(+),K(+)-ATPase activity and cell sodium transport by promoting the internalization of active molecules from the plasma membrane, whereas angiotensin II (ATII) stimulates its activity by recruiting new molecules to the plasma membrane. They achieve such effects by activating multiple and distinct signalling molecules in a hierarchical manner. The purpose of this study was to investigate whether dopamine and ATII utilize scaffold organizer proteins as components of their signalling networks, in order to avoid deleterious cross talk. EXPERIMENTAL APPROACH Attention was focused on a multiple PDZ domain protein, Pals-associated tight junction protein (PATJ). Ectopic expression of PATJ in renal epithelial cells in culture was used to study its interaction with components of the dopamine signalling cascade. Similarly, expression of PATJ deletion mutants was employed to analyse its functional relevance during dopamine-, ATII- and insulin-dependent regulation of Na(+),K(+)-ATPase. KEY RESULTS Dopamine receptors and components of its signalling cascade mediating inhibition of Na(+),K(+)-ATPase interact with PATJ. Inhibition of Na(+),K(+)-ATPase by dopamine was prevented by expression of mutants of PATJ lacking PDZ domains 2, 4 or 5; whereas the stimulatory effect of ATII and insulin on Na(+),K(+)-ATPase was blocked by expression of PATJ lacking PDZ domains 1, 4 or 5. CONCLUSIONS AND IMPLICATIONS A multiple PDZ domain protein may add functionality to G protein-coupled and tyrosine kinase receptors signalling during regulation of Na(+),K(+)-ATPase. Signalling molecules and effectors can be integrated into a functional network by the scaffold organizer protein PATJ via its multiple PDZ domains.
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Affiliation(s)
- Z Chen
- Department of Medicine, Karolinska Institutet, Karolinska University Hospital-Solna, Stockholm, Sweden
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Bagrov AY, Shapiro JI, Fedorova OV. Endogenous cardiotonic steroids: physiology, pharmacology, and novel therapeutic targets. Pharmacol Rev 2009; 61:9-38. [PMID: 19325075 PMCID: PMC2763610 DOI: 10.1124/pr.108.000711] [Citation(s) in RCA: 384] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Endogenous cardiotonic steroids (CTS), also called digitalis-like factors, have been postulated to play important roles in health and disease for nearly half a century. Recent discoveries, which include the specific identification of endogenous cardenolide (endogenous ouabain) and bufadienolide (marinobufagenin) CTS in humans along with the delineation of an alternative mechanism by which CTS can signal through the Na(+)/K(+)-ATPase, have increased the interest in this field substantially. Although CTS were first considered important in the regulation of renal sodium transport and arterial pressure, more recent work implicates these hormones in the regulation of cell growth, differentiation, apoptosis, and fibrosis, the modulation of immunity and of carbohydrate metabolism, and the control of various central nervous functions and even behavior. This review focuses on the physiological interactions between CTS and other regulatory systems that may be important in the pathophysiology of essential hypertension, preeclampsia, end-stage renal disease, congestive heart failure, and diabetes mellitus. Based on our increasing understanding of the regulation of CTS as well as the molecular mechanisms of these hormone increases, we also discuss potential therapeutic strategies.
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Affiliation(s)
- Alexei Y Bagrov
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, 5600 Nathan Shock Dr., Baltimore, MD 21224, USA.
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Seidlerova J, Staessen JA, Bochud M, Nawrot T, Casamassima N, Citterio L, Kuznetsova T, Jin Y, Manunta P, Richart T, Struijker-Boudier HA, Fagard R, Filipovsky J, Bianchi G. Arterial properties in relation to genetic variations in the adducin subunits in a white population. Am J Hypertens 2009; 22:21-6. [PMID: 18787518 DOI: 10.1038/ajh.2008.261] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Adducin is a membrane skeleton protein, which consists of either alpha- and beta- or alpha- and gamma-subunits. We investigated whether arterial characteristics might be related to the genes encoding ADD1 (Gly460Trp-rs4961), ADD2 (C1797T-rs4984), and ADD3 (IVS11+386A>G-rs3731566). METHODS We randomly recruited 1,126 Flemish subjects (mean age, 43.8 years; 50.3% women). Using a wall-tracking ultrasound system, we measured the properties of the carotid, femoral, and brachial arteries. We studied multivariate-adjusted phenotype-genotype associations, using a population- and family-based approach. RESULTS In single-gene analyses, brachial diameter was 0.15 mm (P = 0.0022) larger, and brachial distensibility and cross-sectional compliance were 1.55 x 10(-3)/kPa (P = 0.013) and 0.017 mm(2)/kPa (P = 0.0029) lower in ADD3 AA than ADD3 GG homozygotes with an additive effect of the G allele. In multiple-gene analyses, the association of brachial diameter and distensibility with the ADD3 G allele occurred only in ADD1 GlyGly homozygotes. Otherwise, the associations between the arterial phenotypes in the three vascular beds and the ADD1 or ADD2 polymorphisms were not significant. In family-based analyses, the multivariate-adjusted heritability was 0.52, 0.38, and 0.30 for brachial diameter, distensibility, and cross-sectional compliance, respectively (P < 0.001). There was no evidence for population stratification (0.07 < or = P < or = 0.96). Transmission of the mutated ADD3 G allele was associated with smaller brachial diameter in 342 informative offspring (-0.12 +/- 0.04 mm; P = 0.0085) and in 209 offspring, who were ADD1 GlyGly homozygotes (-0.14 +/- 0.06 mm; P = 0.018). CONCLUSIONS In ADD1 GlyGly homozygotes, the properties of the brachial artery are related to the ADD3 (A386G) polymorphism, but the underlying mechanism needs further clarification.
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Seidlerová J, Staessen JA, Nawrot T, Brand E, Brand-Herrmann SM, Casamassima N, Citterio L, Hasenkamp S, Kuznetsova T, Li Y, Manunta P, Richart T, Struijker-Boudier HA, Fagard R, Filipovskỳ J. Arterial properties in relation to genetic variation in α-adducin and the renin–angiotensin system in a White population. J Hum Hypertens 2008; 23:55-64. [DOI: 10.1038/jhh.2008.113] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Cinelli AR, Efendiev R, Pedemonte CH. Trafficking of Na-K-ATPase and dopamine receptor molecules induced by changes in intracellular sodium concentration of renal epithelial cells. Am J Physiol Renal Physiol 2008; 295:F1117-25. [PMID: 18701625 DOI: 10.1152/ajprenal.90317.2008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Most of the transepithelial transport of sodium in proximal tubules occurs through the coordinated action of the apical sodium/proton exchanger and the basolateral Na-K-ATPase. Hormones that regulate proximal tubule sodium excretion regulate the activities of these proteins. We have previously demonstrated that the level of intracellular sodium concentration modulates the regulation of Na-K-ATPase activity by angiotensin II and dopamine. An increase of a few millimolars in intracellular sodium concentration leads to increased Na-K-ATPase activity without a statistically significant increase in the number of plasma membrane Na-K-ATPase molecules, as determined by cell surface protein biotinylation. Using total internal reflection fluorescence, we detected an increased number of Na-K-ATPase molecules in cytosolic compartments adjacent to the plasma membrane, suggesting that the increased intracellular sodium concentration induces a movement of Na-K-ATPase molecules toward the plasma membrane. While intracellular compartments containing Na-K-ATPase molecules are very close to the plasma membrane, compartments containing type 1 dopamine receptors (D1Rs) are distributed in different parts of the cell cytosol. Fluorescence determinations indicate that an increased intracellular sodium concentration induces the increased colocalization of dopamine receptors with Na-K-ATPase molecules in the region of the plasma membrane. We propose that under in vivo conditions, in response to a sodium load in the lumen of proximal tubules, an increased level of intracellular sodium in epithelial cells is an early event that triggers the cellular response that leads to dopamine inhibition of proximal tubule sodium reabsorption.
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Affiliation(s)
- Angel R Cinelli
- Department of Anatomy and Cell Biology, State University of New York at Brooklyn, Brooklyn, NY, USA
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