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Kakoki M, Ramanathan PV, Hagaman JR, Grant R, Wilder JC, Taylor JM, Charles Jennette J, Smithies O, Maeda-Smithies N. Cyanocobalamin prevents cardiomyopathy in type 1 diabetes by modulating oxidative stress and DNMT-SOCS1/3-IGF-1 signaling. Commun Biol 2021; 4:775. [PMID: 34163008 PMCID: PMC8222371 DOI: 10.1038/s42003-021-02291-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 05/28/2021] [Indexed: 12/27/2022] Open
Abstract
Patients with long-standing diabetes have a high risk for cardiac complications that is exacerbated by increased reactive oxygen species (ROS) production. We found that feeding cyanocobalamin (B12), a scavenger of superoxide, not only prevented but reversed signs of cardiomyopathy in type 1 diabetic Elmo1H/H Ins2Akita/+ mice. ROS reductions in plasma and hearts were comparable to those in mice treated with other antioxidants, N-acetyl-L-cysteine or tempol, but B12 produced better cardioprotective effects. Diabetes markedly decreased plasma insulin-like growth factor (IGF)-1 levels, while B12, but not N-acetyl-L-cysteine nor tempol, restored them. B12 activated hepatic IGF-1 production via normalization of S-adenosylmethionine levels, DNA methyltransferase (DNMT)-1/3a/3b mRNA, and DNA methylation of promoters for suppressor of cytokine signaling (SOCS)-1/3. Reductions of cardiac IGF-1 mRNA and phosphorylated IGF-1 receptors were also restored. Thus, B12 is a promising option for preventing diabetic cardiomyopathy via ROS reduction and IGF-1 retrieval through DNMT-SOCS1/3 signaling.
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Affiliation(s)
- Masao Kakoki
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Purushotham V Ramanathan
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - John R Hagaman
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Ruriko Grant
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jennifer C Wilder
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Joan M Taylor
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - J Charles Jennette
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Oliver Smithies
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Nobuyo Maeda-Smithies
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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2
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Bai X, Mangum K, Kakoki M, Smithies O, Mack CP, Taylor JM. GRAF3 serves as a blood volume-sensitive rheostat to control smooth muscle contractility and blood pressure. Small GTPases 2020; 11:194-203. [PMID: 29099324 PMCID: PMC7549679 DOI: 10.1080/21541248.2017.1375602] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Vascular resistance is a major determinant of BP and is controlled, in large part, by RhoA-dependent smooth muscle cell (SMC) contraction within small peripheral arterioles and previous studies from our lab indicate that GRAF3 is a critical regulator of RhoA in vascular SMC. The elevated contractile responses we observed in GRAF3 deficient vessels coupled with the hypertensive phenotype provided a mechanistic link for the hypertensive locus recently identified within the GRAF3 gene. On the basis of our previous findings that the RhoA signaling axis also controls SMC contractile gene expression and that GRAF3 expression was itself controlled by this pathway, we postulated that GRAF3 serves as an important counter-regulator of SMC phenotype. Indeed, our new findings presented herein indicate that GRAF3 expression acts as a pressure-sensitive rheostat to control vessel tone by both reducing calcium sensitivity and restraining expression of the SMC-specific contractile proteins that support this function. Collectively, these studies highlight the potential therapeutic value of GRAF3 in the control of human hypertension.
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Affiliation(s)
- Xue Bai
- Department of Pathology, University of North Carolina, Chapel Hill, NC, USA
| | - Kevin Mangum
- Department of Pathology, University of North Carolina, Chapel Hill, NC, USA
| | - Masao Kakoki
- Department of Pathology, University of North Carolina, Chapel Hill, NC, USA
| | - Oliver Smithies
- Department of Pathology, University of North Carolina, Chapel Hill, NC, USA
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA
| | - Christopher P. Mack
- Department of Pathology, University of North Carolina, Chapel Hill, NC, USA
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA
| | - Joan M. Taylor
- Department of Pathology, University of North Carolina, Chapel Hill, NC, USA
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA
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3
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Kakoki M, Bahnson EM, Hagaman JR, Siletzky RM, Grant R, Kayashima Y, Li F, Lee EY, Sun MT, Taylor JM, Rice JC, Almeida MF, Bahr BA, Jennette JC, Smithies O, Maeda-Smithies N. Engulfment and cell motility protein 1 potentiates diabetic cardiomyopathy via Rac-dependent and Rac-independent ROS production. JCI Insight 2019; 4:127660. [PMID: 31217360 DOI: 10.1172/jci.insight.127660] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 05/08/2019] [Indexed: 01/31/2023] Open
Abstract
Engulfment and cell motility protein 1 (ELMO1) is part of a guanine nucleotide exchange factor for Ras-related C3 botulinum toxin substrate (Rac), and ELMO1 polymorphisms were identified to be associated with diabetic nephropathy in genome-wide association studies. We generated a set of Akita Ins2C96Y diabetic mice having 5 graded cardiac mRNA levels of ELMO1 from 30% to 200% of normal and found that severe dilated cardiomyopathy develops in ELMO1-hypermorphic mice independent of renal function at age 16 weeks, whereas ELMO1-hypomorphic mice were completely protected. As ELMO1 expression increased, reactive oxygen species indicators, dissociation of the intercalated disc, mitochondrial fragmentation/dysfunction, cleaved caspase-3 levels, and actin polymerization increased in hearts from Akita mice. Cardiomyocyte-specific overexpression in otherwise ELMO1-hypomorphic Akita mice was sufficient to promote cardiomyopathy. Cardiac Rac1 activity was positively correlated with the ELMO1 levels, and oral administration of a pan-Rac inhibitor, EHT1864, partially mitigated cardiomyopathy of the ELMO1 hypermorphs. Disrupting Nox4, a Rac-independent NADPH oxidase, also partially mitigated it. In contrast, a pan-NADPH oxidase inhibitor, VAS3947, markedly prevented cardiomyopathy. Our data demonstrate that in diabetes mellitus ELMO1 is the "rate-limiting" factor of reactive oxygen species production via both Rac-dependent and Rac-independent NADPH oxidases, which in turn trigger cellular signaling cascades toward cardiomyopathy.
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Affiliation(s)
- Masao Kakoki
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Edward M Bahnson
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.,Department of Surgery, Division of Vascular Surgery, and Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - John R Hagaman
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Robin M Siletzky
- Department of Surgery, Division of Vascular Surgery, and Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Ruriko Grant
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Yukako Kayashima
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Feng Li
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Esther Y Lee
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Michelle T Sun
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Joan M Taylor
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Jessica C Rice
- Biotechnology Research and Training Center, University of North Carolina at Pembroke, Pembroke, North Carolina, USA
| | - Michael F Almeida
- Biotechnology Research and Training Center, University of North Carolina at Pembroke, Pembroke, North Carolina, USA
| | - Ben A Bahr
- Biotechnology Research and Training Center, University of North Carolina at Pembroke, Pembroke, North Carolina, USA
| | - J Charles Jennette
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Oliver Smithies
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Nobuyo Maeda-Smithies
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Li F, Kakoki M, Smid M, Boggess K, Wilder J, Hiller S, Bounajim C, Parnell SE, Sulik KK, Smithies O, Maeda-Smithies N. Causative Effects of Genetically Determined High Maternal/Fetal Endothelin-1 on Preeclampsia-Like Conditions in Mice. Hypertension 2018; 71:894-903. [PMID: 29610266 DOI: 10.1161/hypertensionaha.117.10849] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 01/22/2018] [Accepted: 03/06/2018] [Indexed: 12/20/2022]
Abstract
Endothelin-1 (ET-1) is implicated in the pathophysiology of preeclampsia. An association between an EDN1 gene polymorphism with high ET-1 and preeclampsia was reported in humans, but their cause and effect relationships have not been defined. We examined the pregnancy effects in mice with a modified Edn1 allele that increases mRNA stability and thus ET-1 production. Heterozygous Edn1H/+ females showed no obvious abnormalities before pregnancy, but when mated with wild-type (WT) males developed a full spectrum of preeclampsia-like phenotypes, including increased systolic blood pressure, proteinuria, glomerular endotheliosis, and intrauterine fetal growth restriction. At 7.5 days post-coitus, the embryos from Edn1H/+ dams, regardless of their Edn1 genotype, lagged 12 hours in development compared with embryos from WT dams, had disoriented ectoplacental cones, and retained high E-cadherin expression. In contrast, WT females mated with Edn1H/+ males, which also carried half of the fetuses with Edn1H/+ genotype, showed a mild systolic blood pressure increase only. These WT dams had 2× higher plasma soluble fms-like tyrosine kinase-1 than WT dams mated with WT males. In human first trimester trophoblast cells, pharmacological doses of ET-1 increased the cellular sFlt1 transcripts and protein secretion via both type A and B ET-1 receptors. Our data demonstrate that high maternal ET-1 production causes preeclampsia-like phenotypes during pregnancy, affecting both initial stage of trophoblast differentiation/invasion and maternal peripheral vasculature during late gestation. High fetal ET-1 production, however, could cause increased soluble fms-like tyrosine kinase-1 in the maternal circulation and contribute to blood pressure elevation.
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Affiliation(s)
- Feng Li
- From the Department of Pathology and Laboratory Medicine (F.L., M.K., J.W., S.H., O.S., N.M.-S.), Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology (K.B.), School of Medicine (C.B.), and Department of Cell Biology and Physiology (S.E.P., K.K.S.), University of North Carolina; and Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Utah, Salt Lake City (M.S.).
| | - Masao Kakoki
- From the Department of Pathology and Laboratory Medicine (F.L., M.K., J.W., S.H., O.S., N.M.-S.), Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology (K.B.), School of Medicine (C.B.), and Department of Cell Biology and Physiology (S.E.P., K.K.S.), University of North Carolina; and Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Utah, Salt Lake City (M.S.)
| | - Marcela Smid
- From the Department of Pathology and Laboratory Medicine (F.L., M.K., J.W., S.H., O.S., N.M.-S.), Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology (K.B.), School of Medicine (C.B.), and Department of Cell Biology and Physiology (S.E.P., K.K.S.), University of North Carolina; and Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Utah, Salt Lake City (M.S.)
| | - Kim Boggess
- From the Department of Pathology and Laboratory Medicine (F.L., M.K., J.W., S.H., O.S., N.M.-S.), Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology (K.B.), School of Medicine (C.B.), and Department of Cell Biology and Physiology (S.E.P., K.K.S.), University of North Carolina; and Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Utah, Salt Lake City (M.S.)
| | - Jennifer Wilder
- From the Department of Pathology and Laboratory Medicine (F.L., M.K., J.W., S.H., O.S., N.M.-S.), Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology (K.B.), School of Medicine (C.B.), and Department of Cell Biology and Physiology (S.E.P., K.K.S.), University of North Carolina; and Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Utah, Salt Lake City (M.S.)
| | - Sylvia Hiller
- From the Department of Pathology and Laboratory Medicine (F.L., M.K., J.W., S.H., O.S., N.M.-S.), Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology (K.B.), School of Medicine (C.B.), and Department of Cell Biology and Physiology (S.E.P., K.K.S.), University of North Carolina; and Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Utah, Salt Lake City (M.S.)
| | - Carol Bounajim
- From the Department of Pathology and Laboratory Medicine (F.L., M.K., J.W., S.H., O.S., N.M.-S.), Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology (K.B.), School of Medicine (C.B.), and Department of Cell Biology and Physiology (S.E.P., K.K.S.), University of North Carolina; and Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Utah, Salt Lake City (M.S.)
| | - Scott E Parnell
- From the Department of Pathology and Laboratory Medicine (F.L., M.K., J.W., S.H., O.S., N.M.-S.), Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology (K.B.), School of Medicine (C.B.), and Department of Cell Biology and Physiology (S.E.P., K.K.S.), University of North Carolina; and Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Utah, Salt Lake City (M.S.)
| | - Kathleen K Sulik
- From the Department of Pathology and Laboratory Medicine (F.L., M.K., J.W., S.H., O.S., N.M.-S.), Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology (K.B.), School of Medicine (C.B.), and Department of Cell Biology and Physiology (S.E.P., K.K.S.), University of North Carolina; and Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Utah, Salt Lake City (M.S.)
| | - Oliver Smithies
- From the Department of Pathology and Laboratory Medicine (F.L., M.K., J.W., S.H., O.S., N.M.-S.), Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology (K.B.), School of Medicine (C.B.), and Department of Cell Biology and Physiology (S.E.P., K.K.S.), University of North Carolina; and Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Utah, Salt Lake City (M.S.)
| | - Nobuyo Maeda-Smithies
- From the Department of Pathology and Laboratory Medicine (F.L., M.K., J.W., S.H., O.S., N.M.-S.), Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology (K.B.), School of Medicine (C.B.), and Department of Cell Biology and Physiology (S.E.P., K.K.S.), University of North Carolina; and Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Utah, Salt Lake City (M.S.)
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Williams PA, Harder JM, Foxworth NE, Cochran KE, Philip VM, Porciatti V, Smithies O, John SWM. Vitamin B 3 modulates mitochondrial vulnerability and prevents glaucoma in aged mice. Science 2017; 355:756-760. [PMID: 28209901 DOI: 10.1126/science.aal0092] [Citation(s) in RCA: 362] [Impact Index Per Article: 51.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 12/23/2016] [Indexed: 12/25/2022]
Abstract
Glaucomas are neurodegenerative diseases that cause vision loss, especially in the elderly. The mechanisms initiating glaucoma and driving neuronal vulnerability during normal aging are unknown. Studying glaucoma-prone mice, we show that mitochondrial abnormalities are an early driver of neuronal dysfunction, occurring before detectable degeneration. Retinal levels of nicotinamide adenine dinucleotide (NAD+, a key molecule in energy and redox metabolism) decrease with age and render aging neurons vulnerable to disease-related insults. Oral administration of the NAD+ precursor nicotinamide (vitamin B3), and/or gene therapy (driving expression of Nmnat1, a key NAD+-producing enzyme), was protective both prophylactically and as an intervention. At the highest dose tested, 93% of eyes did not develop glaucoma. This supports therapeutic use of vitamin B3 in glaucoma and potentially other age-related neurodegenerations.
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Affiliation(s)
| | | | | | | | | | - Vittorio Porciatti
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Oliver Smithies
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Simon W M John
- The Jackson Laboratory, Bar Harbor, ME 04609, USA. .,Department of Ophthalmology, Tufts University of Medicine, Boston, MA 02111, USA.,The Howard Hughes Medical Institute, Bar Harbor, ME 04609, USA
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Willett JD, Lawrence MG, Wilder JC, Smithies O. A tetraethylene glycol coat gives gold nanoparticles long in vivo half-lives with minimal increase in size. Int J Nanomedicine 2017; 12:2581-2592. [PMID: 28408825 PMCID: PMC5383068 DOI: 10.2147/ijn.s121486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
In this study, we describe the experiments determining whether coating gold nanoparticles with tetraethylene glycol (TEG) provides pharmacologically relevant advantages, such as increased serum half-life and resistance to protein adsorption. Monodisperse TEG-coated, NaBH4-reduced gold nanoparticles with a hydrodynamic size comparable to albumin were synthesized by reducing gold chloride with NaBH4 under alkaline conditions in the presence of TEG-SH. The particles were characterized by gel electrophoresis, column chromatography, and transmission electron microscopy. The nanoparticles were subsequently injected intravenously into mice, and their half-lives and final destinations were determined via photometric analysis, light microscopy (LM), and transmission electron microscopy. The TEG particles had a long half-life (~400 minutes) that was not influenced by splenectomy. After 500 minutes of injection, TEG particles were found in kidney proximal tubule cell vesicles and in spleen red and white pulp. The particles induced apoptosis in the spleen red pulp but not in white pulp or the kidney. Some of the TEG particles appeared to have undergone ligand exchange reactions that increased their charge. The TEG particles were shown to be resistant to nonspecific protein adsorption, as judged by gel electrophoresis and column chromatography. These results demonstrate that naturally monodisperse, small-sized gold nanoparticles coated with TEG have long in vivo plasma half-lives, are minimally toxic, and are resistant to protein adsorption. This suggests that a TEG coating should be considered as an alternative to a polyethylene glycol coating, which is polydisperse and of much larger size.
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Affiliation(s)
- Julian Ds Willett
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Marlon G Lawrence
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jennifer C Wilder
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Oliver Smithies
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Lawrence M, Testen A, Koklic T, Smithies O. A Simple Method for the Size Controlled Synthesis of Stable Oligomeric Clusters of Gold Nanoparticles under Ambient Conditions. J Vis Exp 2016:e53388. [PMID: 26890032 PMCID: PMC4781725 DOI: 10.3791/53388] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Reducing dilute aqueous HAuCl4 with sodium thiocyanate (NaSCN) under alkaline conditions produces 2 to 3 nm diameter nanoparticles. Stable grape-like oligomeric clusters of these yellow nanoparticles of narrow size distribution are synthesized under ambient conditions via two methods. The delay-time method controls the number of subunits in the oligoclusters by varying the time between the addition of HAuCl₄ to alkaline solution and the subsequent addition of reducing agent, NaSCN. The yellow oligoclusters produced range in size from ~3 to ~25 nm. This size range can be further extended by an add-on method utilizing hydroxylated gold chloride (Na(+)[Au(OH₄-x)Clx](-)) to auto-catalytically increase the number of subunits in the as-synthesized oligocluster nanoparticles, providing a total range of 3 nm to 70 nm. The crude oligocluster preparations display narrow size distributions and do not require further fractionation for most purposes. The oligoclusters formed can be concentrated >300 fold without aggregation and the crude reaction mixtures remain stable for weeks without further processing. Because these oligomeric clusters can be concentrated before derivatization they allow expensive derivatizing agents to be used economically. In addition, we present two models by which predictions of particle size can be made with great accuracy.
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Affiliation(s)
- Marlon Lawrence
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill;
| | - Anze Testen
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill
| | - Tilen Koklic
- Condensed Matter Physics Department, Laboratory of Biophysics, Jozef Stefan Institute;
| | - Oliver Smithies
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill;
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Chang AS, Hathaway CK, Smithies O, Kakoki M. Transforming growth factor-β1 and diabetic nephropathy. Am J Physiol Renal Physiol 2015; 310:F689-F696. [PMID: 26719364 DOI: 10.1152/ajprenal.00502.2015] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 12/24/2015] [Indexed: 12/19/2022] Open
Abstract
Transforming growth factor-β1 (TGF-β1) is established to be involved in the pathogenesis of diabetic nephropathy. The diabetic milieu enhances oxidative stress and induces the expression of TGF-β1. TGF-β1 promotes cell hypertrophy and extracellular matrix accumulation in the mesangium, which decreases glomerular filtration rate and leads to chronic renal failure. Recently, TGF-β1 has been demonstrated to regulate urinary albumin excretion by both increasing glomerular permeability and decreasing reabsorption in the proximal tubules. TGF-β1 also increases urinary excretion of water, electrolytes and glucose by suppressing tubular reabsorption in both normal and diabetic conditions. Although TGF-β1 exerts hypertrophic and fibrogenic effects in diabetic nephropathy, whether suppression of the function of TGF-β1 can be an option to prevent or treat the complication is still controversial. This is partly because adrenal production of mineralocorticoids could be augmented by the suppression of TGF-β1. However, differentiating the molecular mechanisms for glomerulosclerosis from those for the suppression of the effects of mineralocorticoids by TGF-β1 may assist in developing novel therapeutic strategies for diabetic nephropathy. In this review, we discuss recent findings on the role of TGF-β1 in diabetic nephropathy.
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Affiliation(s)
- Albert S Chang
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Catherine K Hathaway
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Oliver Smithies
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Masao Kakoki
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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Abstract
Professor Oliver Smithies is the Weatherspoon Eminent Distinguished Professor of Pathology and Laboratory Medicine at the University of North Carolina, Chapel Hill. Along with Mario Capecchi and Martin Evans, Oliver was awarded the Nobel Prize in Medicine in Physiology or Medicine in 2007 for his contributions to the development of gene targeting using homologous recombination in embryonic stem cells. This technique has had an immense impact on biomedical research over the past two decades. Professor Smithies has had a long and distinguished career as a researcher and mentor. Here, he provides an entertaining and enlightening discussion of his life in science.
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Affiliation(s)
- Oliver Smithies
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina 27599
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Matsuki K, Hathaway CK, Lawrence MG, Smithies O, Kakoki M. The role of transforming growth factor β1 in the regulation of blood pressure. Curr Hypertens Rev 2015; 10:223-38. [PMID: 25801626 DOI: 10.2174/157340211004150319123313] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 02/19/2015] [Accepted: 02/23/2015] [Indexed: 01/21/2023]
Abstract
Although human association studies suggest a link between polymorphisms in the gene encoding transforming growth factor (TGF) β1 and differing blood pressure levels, a causative mechanism for this correlation remains elusive. Recently we have generated a series of mice with graded expression of TGFβ1, ranging from approximately 10% to 300% compared to normal. We have found that blood pressure and plasma volume are negatively regulated by TGFβ1. Of note, the 10% hypomorph exhibits primary aldosteronism and markedly impaired urinary excretion of water and electrolytes. We here review previous literature highlighting the importance of TGFβ signaling as a natriuretic system, which we postulate is a causative mechanism explaining how polymorphisms in TGFβ1 could influence blood pressure levels.
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Affiliation(s)
| | | | | | | | - Masao Kakoki
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, CB #7525, 701 Brinkhous-Bullitt Building, Chapel Hill, NC 27599-7525, USA.
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Smithies O, Lawrence M, Testen A, Horne L, Wilder J, Altenburg M, Bleasdale B, Maeda N, Koklic T. Stable oligomeric clusters of gold nanoparticles: preparation, size distribution, derivatization, and physical and biological properties. Langmuir 2014; 30:13394-13404. [PMID: 25317930 PMCID: PMC4230385 DOI: 10.1021/la5032637] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 09/27/2014] [Indexed: 06/04/2023]
Abstract
Reducing dilute aqueous HAuCl4 with NaSCN under alkaline conditions produces 2-3 nm diameter yellow nanoparticles without the addition of extraneous capping agents. We here describe two very simple methods for producing highly stable oligomeric grape-like clusters (oligoclusters) of these small nanoparticles. The oligoclusters have well-controlled diameters ranging from ∼5 to ∼30 nm, depending mainly on the number of subunits in the cluster. Our first ["delay-time"] method controls the size of the oligoclusters by varying from seconds to hours the delay time between making the HAuCl4 alkaline and adding the reducing agent, NaSCN. Our second ["add-on"] method controls size by using yellow nanoparticles as seeds onto which varying amounts of gold derived from "hydroxylated gold", Na(+)[Au(OH4-x)Clx](-), are added-on catalytically in the presence of NaSCN. Possible reaction mechanisms and a simple kinetic model fitting the data are discussed. The crude oligocluster preparations have narrow size distributions, and for most purposes do not require fractionation. The oligoclusters do not aggregate after ∼300-fold centrifugal-filter concentration, and at this high concentration are easily derivatized with a variety of thiol-containing reagents. This allows rare or expensive derivatizing reagents to be used economically. Unlike conventional glutathione-capped nanoparticles of comparable gold content, large oligoclusters derivatized with glutathione do not aggregate at high concentrations in phosphate-buffered saline (PBS) or in the circulation when injected into mice. Mice receiving them intravenously show no visible signs of distress. Their sizes can be made small enough to allow their excretion in the urine or large enough to prevent them from crossing capillary basement membranes. They are directly visible in electron micrographs without enhancement, and can model the biological fate of protein-like macromolecules with controlled sizes and charges. The ease of derivatizing the oligoclusters makes them potentially useful for presenting pharmacological agents to different tissues while controlling escape of the reagents from the circulation.
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Affiliation(s)
- Oliver Smithies
- Department of Pathology and Laboratory
Medicine, and Department of Chemistry, University of
North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Marlon Lawrence
- Department of Pathology and Laboratory
Medicine, and Department of Chemistry, University of
North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Anze Testen
- Condensed
Matter Physics Department, Laboratory of Biophysics, “Jožef Stefan” Institute, Ljubljana 1001, Slovenia
| | - Lloyd
P. Horne
- Department of Pathology and Laboratory
Medicine, and Department of Chemistry, University of
North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Jennifer Wilder
- Department of Pathology and Laboratory
Medicine, and Department of Chemistry, University of
North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Michael Altenburg
- Department of Pathology and Laboratory
Medicine, and Department of Chemistry, University of
North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Ben Bleasdale
- Department of Pathology and Laboratory
Medicine, and Department of Chemistry, University of
North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Nobuyo Maeda
- Department of Pathology and Laboratory
Medicine, and Department of Chemistry, University of
North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Tilen Koklic
- Condensed
Matter Physics Department, Laboratory of Biophysics, “Jožef Stefan” Institute, Ljubljana 1001, Slovenia
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14
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Affiliation(s)
- S Colby Allred
- University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - William J Schreiner
- University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Oliver Smithies
- University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
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15
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Wang CH, Smithies O, Takahashi N. Inhibition of angiotensin II increases hypothalamic thyroid hormone and stimulates orexigenic NPY/AgRP neurons (LB437). FASEB J 2014. [DOI: 10.1096/fasebj.28.1_supplement.lb437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- CHih‐Hong Wang
- Biological Science and Technology National Chiao Tung University Hsin‐ChuTaiwan
| | - Oliver Smithies
- Pathology and Laboratory Medicine University of North Carolina at CHAPEL HILLChapel HillNCUnited States
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16
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Bai X, Lenhart KC, Bird KE, Suen AA, Rojas M, Kakoki M, Li F, Smithies O, Mack CP, Taylor JM. The smooth muscle-selective RhoGAP GRAF3 is a critical regulator of vascular tone and hypertension. Nat Commun 2013; 4:2910. [PMID: 24335996 PMCID: PMC4237314 DOI: 10.1038/ncomms3910] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Accepted: 11/11/2013] [Indexed: 12/13/2022] Open
Abstract
Although hypertension is a worldwide health issue, an incomplete understanding of its aetiology has hindered our ability to treat this complex disease. Here we identify arhgap42 (also known as GRAF3) as a Rho-specific GAP expressed specifically in smooth muscle cells (SMCs) in mice and humans. We show that GRAF3-deficient mice exhibit significant hypertension and increased pressor responses to angiotensin II and endothelin-1; these effects are prevented by treatment with the Rho-kinase inhibitor, Y27632. RhoA activity and myosin light chain phosphorylation are elevated in GRAF3-depleted SMCs in vitro and in vivo, and isolated vessel segments from GRAF3-deficient mice show increased contractility. Taken together, our data indicate that GRAF3-mediated inhibition of RhoA activity in vascular SMCs is necessary for maintaining normal blood pressure homoeostasis. Moreover, these findings provide a potential mechanism for a hypertensive locus recently identified within arhgap42 and provide a foundation for the future development of innovative hypertension therapies.
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Affiliation(s)
- Xue Bai
- Department of Pathology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Kaitlin C. Lenhart
- Department of Pathology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Kim E. Bird
- Department of Pathology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Alisa A. Suen
- Department of Pathology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Mauricio Rojas
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Masao Kakoki
- Department of Pathology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Feng Li
- Department of Pathology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Oliver Smithies
- Department of Pathology, University of North Carolina, Chapel Hill, NC 27599, USA
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Christopher P. Mack
- Department of Pathology, University of North Carolina, Chapel Hill, NC 27599, USA
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Joan M. Taylor
- Department of Pathology, University of North Carolina, Chapel Hill, NC 27599, USA
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC 27599, USA
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17
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Vashistha H, Singhal PC, Malhotra A, Husain M, Mathieson P, Saleem MA, Kuriakose C, Seshan S, Wilk A, Delvalle L, Peruzzi F, Giorgio M, Pelicci PG, Smithies O, Kim HS, Kakoki M, Reiss K, Meggs LG. Null mutations at the p66 and bradykinin 2 receptor loci induce divergent phenotypes in the diabetic kidney. Am J Physiol Renal Physiol 2012; 303:F1629-40. [PMID: 23019230 DOI: 10.1152/ajprenal.00246.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Candidate genes have been identified that confer increased risk for diabetic glomerulosclerosis (DG). Mice heterozygous for the Akita (Ins2(+/C96Y)) diabetogenic mutation with a second mutation introduced at the bradykinin 2 receptor (B2R(-/-)) locus express a disease phenotype that approximates human DG. Src homology 2 domain transforming protein 1 (p66) controls mitochondrial metabolism and cellular responses to oxidative stress, aging, and apoptosis. We generated p66-null Akita mice to test whether inactivating mutations at the p66 locus will rescue kidneys of Akita mice from disease-causing mutations at the Ins2 and B2R loci. Here we show null mutations at the p66 and B2R loci interact with the Akita (Ins2(+/C96Y)) mutation, independently and in combination, inducing divergent phenotypes in the kidney. The B2R(-/-) mutation induces detrimental phenotypes, as judged by increased systemic and renal levels of oxidative stress, histology, and urine albumin excretion, whereas the p66-null mutation confers a powerful protection phenotype. To elucidate the mechanism(s) of the protection phenotype, we turned to our in vitro system. Experiments with cultured podocytes revealed previously unrecognized cross talk between p66 and the redox-sensitive transcription factor p53 that controls hyperglycemia-induced ROS metabolism, transcription of p53 target genes (angiotensinogen, angiotensin II type-1 receptor, and bax), angiotensin II generation, and apoptosis. RNA-interference targeting p66 inhibits all of the above. Finally, protein levels of p53 target genes were upregulated in kidneys of Akita mice but unchanged in p66-null Akita mice. Taken together, p66 is a potential molecular target for therapeutic intervention in DG.
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Affiliation(s)
- Himanshu Vashistha
- Institute for Translational Research, Nephrology Research Laboratory, Ochsner Health Foundation, Dept. of Nephrology, New Orleans, LA 70121, USA
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18
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Li F, Hagaman JR, Kim HS, Maeda N, Jennette JC, Faber JE, Karumanchi SA, Smithies O, Takahashi N. eNOS deficiency acts through endothelin to aggravate sFlt-1-induced pre-eclampsia-like phenotype. J Am Soc Nephrol 2012; 23:652-60. [PMID: 22282588 DOI: 10.1681/asn.2011040369] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Excess soluble fms-like tyrosine kinase 1 (sFlt-1) of vascular endothelial growth factor receptor 1 secreted from the placenta causes pre-eclampsia-like features by antagonizing vascular endothelial growth factor signaling, which can lead to reduced endothelial nitric oxide synthase (eNOS) activity; the effect of this concomitant decrease in eNOS activity is unknown. We tested whether the decrease in nitric oxide occurring in female mice lacking eNOS aggravates the pre-eclampsia-like phenotype induced by increased sFlt-1. Untreated eNOS-deficient female mice had higher BP than wild-type mice. Adenovirus-mediated overexpression of sFlt-1 increased systolic BP by approximately 27 mmHg and led to severe loss of fenestration of glomerular capillary endothelial cells in both eNOS-deficient and wild-type mice. However, only the eNOS-deficient sFlt-1 mice exhibited severe foot process effacement. Compared with wild-type sFlt-1 mice, eNOS-deficient sFlt-1 mice also showed markedly higher urinary albumin excretion (467±74 versus 174±23 μg/d), lower creatinine clearance (126±29 versus 452±63 μl/min), and more severe endotheliosis. Expression of preproendothelin-1 (ET-1) and its ET(A) receptor in the kidney was higher in eNOS-deficient sFlt-1 mice than in wild-type sFlt-1 mice. Furthermore, the selective ET(A) receptor antagonist ambrisentan attenuated the increases in BP and urinary albumin excretion and ameliorated endotheliosis in both wild-type and eNOS-deficient sFlt-1 mice. Ambrisentan improved creatinine clearance and podocyte effacement in eNOS-deficient sFlt-1 mice. In conclusion, reduced maternal eNOS/nitric oxide exacerbates the sFlt1-related pre-eclampsia-like phenotype through activation of the endothelin system.
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Affiliation(s)
- Feng Li
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
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19
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Abstract
Arne Tiselius' moving boundary electrophoresis method was still in general use in 1951 when this personal history begins, although zonal electrophoresis with a variety of supporting media (e.g., filter paper or starch grains) was beginning to replace it. This chapter is an account of 10 years of experiments carried out by the author during which molecular sieving gel electrophoresis was developed and common genetic variants of two proteins, haptoglobin and transferrin, were discovered in normal individuals. Most of the figures are images of pages from the author's laboratory notebooks, which are still available, so that some of the excitement of the time and the humorous moments are perhaps apparent. Alkaline gels, acidic gels with and without denaturants, vertical gels, two-dimensional gels, and gels with differences in starch concentration are presented. The subtle details that can be discerned in these various gels played an indispensable role in determining the nature of the change in the haptoglobin gene (Hp) that leads to the polymeric series characteristic of Hp ( 2 ) /Hp ( 2 ) homozygotes. Where possible, the names of scientific friends who made this saga of gel electrophoresis so memorable and enjoyable are gratefully included.
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Affiliation(s)
- Oliver Smithies
- University of North Carolina School of Medicine, Chapel Hill, NC, USA.
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20
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Pandya K, Kohro T, Mimura I, Kobayashi M, Wada Y, Kodama T, Smithies O. Distribution of histone3 lysine 4 trimethylation at T3-responsive loci in the heart during reversible changes in gene expression. Gene Expr 2012; 15:183-98. [PMID: 22783727 PMCID: PMC3607203 DOI: 10.3727/105221612x13372578119698] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Expression in the adult heart of a number of cardiac genes, including the two genes comprising the cardiac myosin heavy chain locus (Myh), is controlled by thyroid hormone (T3) levels, but there is minimal information concerning the epigenetic status of the genes when their expressions change. We fed mice normal chow or a propyl thio uracil (PTU, an inhibitor of T3 production) diet for 6 weeks, or the PTU diet for 6 weeks followed by normal chow for a further 2 weeks. Heart ventricles from these groups were then used for ChIP-seq analyses with an antibody to H3K4me3, a well-documented epigenetic marker of gene activation. The resulting data show that, at the Myh7 locus, H3K4me3 modifications are induced primarily at 5' transcribed region in parallel with increased expression of beta myosin heavy chain (MHC). At the Myh6 locus, decreases in H3K4me3 modifications occurred at the promoter and 5' transcribed region. Extensive H3K4me3 modifications also occurred at the intergenic region between the two Myh genes, which extended into the 3' transcribed region of Myh7. The PTU-induced changes in H3K4me3 levels are, for the most part, reversible but are not invariably complete. We found full restoration of Myh6 gene expression upon PTU withdrawal; however, the H3K4me3 pattern was only partially restored at Myh6, suggesting that full reexpression of Myh6 does not require that the H3K4me3 modifications return fully to the untreated conditions. Together, our data show that the H3K4me3 modification is an epigenetic marker closely associated with changes in Myh gene expression.
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Affiliation(s)
- Kumar Pandya
- *Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Takahide Kohro
- †Department of Molecular Biology and Medicine, The Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Imari Mimura
- †Department of Molecular Biology and Medicine, The Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Mika Kobayashi
- †Department of Molecular Biology and Medicine, The Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Youichiro Wada
- †Department of Molecular Biology and Medicine, The Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Tatsuhiko Kodama
- †Department of Molecular Biology and Medicine, The Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Oliver Smithies
- *Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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21
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Abstract
Formation of a fully functional four-chambered heart involves an intricate and complex series of events that includes precise spatial-temporal regulation of cell specification, proliferation, and migration. The formation of the ventricular septum during mid-gestation ensures the unidirectional flow of blood, and is necessary for postnatal viability. Notably, a majority of all congenital malformations of the cardiovascular system in humans involve septal abnormalities which afflict 1 out of 100 newborn children in the United States. Thus, a clear understanding of the precise mechanisms involved in this morphogenetic event will undoubtedly reveal important therapeutic targets. The final step in valvuloseptal morphogenesis occurs, in part, by directed movement of flanking myocytes into the cushion mesenchyme. In order to identify the molecular mechanisms that regulate this critical myocyte function, we have developed two in vitro methodologies; a transwell assay to assess population changes in motility and a single-cell tracking assay to identify signals that drive the coordinated movement of these cells. These methods have proven effective to identify focal adhesion kinase (FAK) as an intracellular component that is critical for myocyte chemotaxis.
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Affiliation(s)
- Britni Zajac
- Department of Pathology and McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA
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22
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Affiliation(s)
- Kumar Pandya
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7525, USA
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Pandya K, Porter K, Rockman HA, Smithies O. Decreased beta-adrenergic responsiveness following hypertrophy occurs only in cardiomyocytes that also re-express beta-myosin heavy chain. Eur J Heart Fail 2010; 11:648-52. [PMID: 19553396 DOI: 10.1093/eurjhf/hfp073] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
AIMS Cardiac hypertrophy is associated with a reduction in the contractile response to beta-adrenergic stimulation, and with re-expression of foetal genes such as beta-myosin heavy chain (MHC). However, whether these two markers of pathology develop concordantly in the same individual cells or independently in different cells is not known. METHODS AND RESULTS To answer this question, we examined the beta-adrenergic response of individual beta-MHC expressing and non-expressing myocytes from hypertrophic hearts, using a previously generated mouse model (YFP/beta-MHC) in which a yellow fluorescent protein (YFP) is fused to the native beta-MHC protein allowing easy identification of beta-MHC expressing cells. Yellow fluorescent protein/beta-MHC mice were submitted to 4 weeks of transverse aortic constriction (TAC), and the contractile parameters of isolated individual myocytes in response to the beta-adrenergic agonist isoproterenol were assessed. Our results demonstrate that the decrease in isoproterenol-induced cell shortening that develops in TAC hearts occurs only in those hypertrophic myocytes that re-express beta-MHC. Hypertrophic myocytes that do not express beta-MHC have contractility indices indistinguishable from non-TAC controls. CONCLUSION These data show that the reduction of beta-adrenergic response occurs only in subsets, rather than in all myocytes, and is coincident with re-expression of beta-MHC.
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Affiliation(s)
- Kumar Pandya
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599-7525, USA
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25
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Wende AR, Soto J, Olsen CD, Pires KMP, Schell JC, Larrieu-Lahargue F, Litwin SE, Kakoki M, Takahashi N, Smithies O, Abel ED. Loss of bradykinin signaling does not accelerate the development of cardiac dysfunction in type 1 diabetic akita mice. Endocrinology 2010; 151:3536-42. [PMID: 20501666 PMCID: PMC2940524 DOI: 10.1210/en.2010-0256] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Bradykinin signaling has been proposed to play either protective or deleterious roles in the development of cardiac dysfunction in response to various pathological stimuli. To further define the role of bradykinin signaling in the diabetic heart, we examined cardiac function in mice with genetic ablation of both bradykinin B1 and B2 receptors (B1RB2R(-/-)) in the context of the Akita model of insulin-deficient type 1 diabetes (Ins2(Akita/+)). In 5-month-old diabetic and nondiabetic, wild-type and B1RB2R(-/-) mice, in vivo cardiac contractile function was determined by left-ventricular (LV) catheterization and echocardiography. Reactive oxygen species levels were measured by 2'-7'-dichlorofluorescein diacetate fluorescence. Mitochondrial function and ATP synthesis were determined in saponin-permeabilized cardiac fibers. LV systolic pressure and the peak rate of LV pressure rise and decline were decreased with diabetes but did not deteriorate further with loss of bradykinin signaling. Wall thinning and reduced ejection fractions in Akita mouse hearts were partially attenuated by B1RB2R deficiency, although other parameters of LV function were unaffected. Loss of bradykinin signaling did not increase fibrosis in Ins2(Akita/+) diabetic mouse hearts. Mitochondrial dysfunction was not exacerbated by B1RB2R deficiency, nor was there any additional increase in tissue levels of reactive oxygen species. Thus, loss of bradykinin B2 receptor signaling does not abrogate the previously reported beneficial effect of inhibition of B1 receptor signaling. In conclusion, complete loss of bradykinin expression does not worsen cardiac function or increase myocardial fibrosis in diabetes.
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MESH Headings
- Animals
- Bradykinin/metabolism
- Bradykinin/physiology
- Diabetes Mellitus, Experimental/complications
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/physiopathology
- Diabetes Mellitus, Type 1/complications
- Diabetes Mellitus, Type 1/genetics
- Diabetes Mellitus, Type 1/metabolism
- Diabetes Mellitus, Type 1/physiopathology
- Female
- Heart/physiopathology
- Heart Diseases/etiology
- Heart Diseases/genetics
- Heart Diseases/physiopathology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Mitochondria, Heart/pathology
- Mitochondria, Heart/physiology
- Myocardium/pathology
- Oxidative Stress/genetics
- Receptor, Bradykinin B1/deficiency
- Receptor, Bradykinin B1/genetics
- Receptor, Bradykinin B2/deficiency
- Receptor, Bradykinin B2/genetics
- Signal Transduction/genetics
- Time Factors
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Affiliation(s)
- Adam R Wende
- Program in Molecular Medicine and Division of Endocrinology, Metabolism, and Diabetes, University of Utah, School of Medicine, Salt Lake City, Utah 84112, USA
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26
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Messadi E, Vincent MP, Griol-Charhbili V, Mandet C, Colucci J, Krege JH, Bruneval P, Bouby N, Smithies O, Alhenc-Gelas F, Richer C. Genetically determined angiotensin converting enzyme level and myocardial tolerance to ischemia. FASEB J 2010. [PMID: 20667972 DOI: 10.1096/fj.10.165902] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Angiotensin I-converting enzyme (ACE; kininase II) levels in humans are genetically determined. ACE levels have been linked to risk of myocardial infarction, but the association has been inconsistent, and the causality underlying it remains undocumented. We tested the hypothesis that genetic variation in ACE levels influences myocardial tolerance to ischemia. We studied ischemia-reperfusion injury in mice bearing 1 (ACE1c), 2 (ACE2c, wild type), or 3 (ACE3c) functional copies of the ACE gene and displaying an ACE level range similar to humans. Infarct size in ACE1c was 29% lower than in ACE2c (P<0.05). Pretreatment with a kinin B2 receptor antagonist suppressed this reduction. In ACE3c, infarct size was the same as in ACE2c. But ischemic preconditioning, which reduced infarct size in ACE2c (-63%, P<0.001) and ACE1c (-52%, P<0.05), was not efficient in ACE3c (-2%, NS, P<0.01 vs. ACE2c). In ACE3c, ischemic preconditioning did not decrease myocardial inflammation or cardiomyocyte apoptosis. Pretreatment with a renin inhibitor had no cardioprotective effect in ACE2c, but in ACE3c partially restored (38%) the cardioprotection of ischemic preconditioning. Thus, a modest genetic increase in ACE impairs myocardial tolerance to ischemia. ACE level plays a critical role in cardiac ischemia, through both kinin and angiotensin mediated mechanisms.
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Affiliation(s)
- Erij Messadi
- INSERM U872, Centre de Recherche des Cordeliers, Paris, France
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27
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Messadi E, Vincent MP, Griol-Charhbili V, Mandet C, Colucci J, Krege JH, Bruneval P, Bouby N, Smithies O, Alhenc-Gelas F, Richer C. Genetically determined angiotensin converting enzyme level and myocardial tolerance to ischemia. FASEB J 2010; 24:4691-700. [PMID: 20667972 DOI: 10.1096/fj.10-165902] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Angiotensin I-converting enzyme (ACE; kininase II) levels in humans are genetically determined. ACE levels have been linked to risk of myocardial infarction, but the association has been inconsistent, and the causality underlying it remains undocumented. We tested the hypothesis that genetic variation in ACE levels influences myocardial tolerance to ischemia. We studied ischemia-reperfusion injury in mice bearing 1 (ACE1c), 2 (ACE2c, wild type), or 3 (ACE3c) functional copies of the ACE gene and displaying an ACE level range similar to humans. Infarct size in ACE1c was 29% lower than in ACE2c (P<0.05). Pretreatment with a kinin B2 receptor antagonist suppressed this reduction. In ACE3c, infarct size was the same as in ACE2c. But ischemic preconditioning, which reduced infarct size in ACE2c (-63%, P<0.001) and ACE1c (-52%, P<0.05), was not efficient in ACE3c (-2%, NS, P<0.01 vs. ACE2c). In ACE3c, ischemic preconditioning did not decrease myocardial inflammation or cardiomyocyte apoptosis. Pretreatment with a renin inhibitor had no cardioprotective effect in ACE2c, but in ACE3c partially restored (38%) the cardioprotection of ischemic preconditioning. Thus, a modest genetic increase in ACE impairs myocardial tolerance to ischemia. ACE level plays a critical role in cardiac ischemia, through both kinin and angiotensin mediated mechanisms.
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Affiliation(s)
- Erij Messadi
- INSERM U872, Centre de Recherche des Cordeliers, Paris, France
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28
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Koller BH, Marrack P, Kappler JW, Smithies O. Normal development of mice deficient in beta 2M, MHC class I proteins, and CD8+ T cells. 1990. J Immunol 2010; 184:4592-4595. [PMID: 20410496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
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Abstract
The two genes of the cardiac myosin heavy chain (MHC) locus-alpha-MHC (aMHC) and beta-MHC (bMHC)--are reciprocally regulated in the mouse ventricle during development and in adult conditions such as hypothyroidism and pathological cardiac hypertrophy. Their expressions are under the control of thyroid hormone T3 levels. To gain insights into the epigenetic mechanisms that underlie this inducible and reversible switching of the aMHC and bMHC isoforms, we have investigated the histone modification patterns that occur over the two cardiac MHC promoters during T3-mediated reversible switching of gene expression. Mice fed a diet of propylthiouracil (PTU, an inhibitor of T3 synthesis) for 2 weeks dramatically reduce aMHC mRNA expression and increase bMHC mRNA levels to high levels, while a subsequent withdrawal of PTU diet for 2 weeks completely reverses the T3-mediated changes in MHC expression. Using hearts from mice treated in this way, we carried out chromatin immunoprecipitation-qPCR assays with antibodies against acetylated histone H3 (H3ac) and trimethylated histone (H3K4me3)-two well-documented markers of activation. Our results show that the reexpression of bMHC is associated at the bMHC promoter with increased H3ac but not H3K4me3. In contrast, the silencing of aMHC is associated at its promoter with decreased H3K4me3, but not decreased H3ac. The epigenetic changes at the two MHC promoters are completely reversed when the gene expression returns to initial levels. These data indicate that during reciprocal and inducible gene expression H3ac parallels bMHC isoform expression while H3K4me3 parallels expression of the tightly linked aMHC isoform.
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Affiliation(s)
- Kumar Pandya
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7525, USA
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Brosius FC, Alpers CE, Bottinger EP, Breyer MD, Coffman TM, Gurley SB, Harris RC, Kakoki M, Kretzler M, Leiter EH, Levi M, McIndoe RA, Sharma K, Smithies O, Susztak K, Takahashi N, Takahashi T. Mouse models of diabetic nephropathy. J Am Soc Nephrol 2009; 20:2503-12. [PMID: 19729434 DOI: 10.1681/asn.2009070721] [Citation(s) in RCA: 426] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Diabetic nephropathy is a major cause of ESRD worldwide. Despite its prevalence, a lack of reliable animal models that mimic human disease has delayed the identification of specific factors that cause or predict diabetic nephropathy. The Animal Models of Diabetic Complications Consortium (AMDCC) was created in 2001 by the National Institutes of Health to develop and characterize models of diabetic nephropathy and other complications. This interim report and our online supplement detail the progress made toward that goal, specifically in the development and testing of murine models. Updates are provided on validation criteria for early and advanced diabetic nephropathy, phenotyping methods, the effect of background strain on nephropathy, current best models of diabetic nephropathy, negative models, and views of future directions. AMDCC investigators and other investigators in the field have yet to validate a complete murine model of human diabetic kidney disease. Nonetheless, the critical analysis of existing murine models substantially enhances our understanding of this disease process.
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Affiliation(s)
- Frank C Brosius
- University of Michigan,1150 W. Medical Center Drive, Ann Arbor, MI 48109-0680, USA.
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Abstract
In view of the well-known phenomenon of trophoblast immune privilege, trophoblast stem cells (TSCs) might be expected to be immune privileged, which could be of interest for cell or gene therapies. Yet in the ectopic sites tested so far, TSC transplants fail to show noticeable immune privilege and seem to lack physiological support. However, we show here that after portal venous injection, green fluorescent protein (GFP)-labeled TSCs survive for several months in the livers of allogeneic female but not male mice. Gonadectomy experiments revealed that this survival does not require the presence of ovarian hormones but does require the absence of testicular factors. By contrast, GFP-labeled allogeneic embryonic stem cells (ESCs) are reliably rejected; however, these same ESCs survive when mixed with unlabeled TSCs. The protective effect does not require immunological compatibility between ESCs and TSCs. Tumors were not observed in animals with either successfully engrafted TSCs or coinjected ESCs. We conclude that in a suitable hormonal context and location, ectopic TSCs can exhibit and confer immune privilege. These findings suggest applications in cell and gene therapy as well as a new model for studying trophoblast immunology and physiology.
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Affiliation(s)
- Jessica Epple-Farmer
- Department of Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
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Abstract
Since kallikrein was discovered as a vasodilatory substance in human urine, the kallikrein-kinin system (KKS) has been considered to play a physiological role in controlling blood pressure. Gene targeting experiments in mice in which the KKS has been inactivated to varying degrees have, however, questioned this role, because basal blood pressures are not altered. Rather, these experiments have shown that the KKS has a different and important role in preventing changes associated with normal senescence in mice, and in reducing the nephropathy and accelerated senescence-associated phenotypes induced in mice by diabetes. Other experiments have shown that the KKS suppresses mitochondrial respiration, partly by nitric oxide and prostaglandins, and that this suppression may be a key to understanding how the KKS influences senescence-related diseases. Here we review the logical progression and experimental data leading to these conclusions, and discuss their relevance to human conditions.
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Affiliation(s)
- Masao Kakoki
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599-7525, USA.
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Affiliation(s)
- Oliver Smithies
- Department of Pathology and Laboratory Medicine, University of North Carolina, 701 Brinkhous-Bullitt, Chapel Hill, NC 27599-7525, USA.
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Picard N, Loffing‐Cueni D, Mihailova M, Makhanova N, Smithies O, Wagner C, Loffing J. Aldosterone‐dependent and ‐independent effects on renal potassium excretion. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.934.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | - Natalia Makhanova
- Department of Pathology and Laboratory MedicineUniversity of North Carolina at Chapel HillChapel HillNC
| | - Oliver Smithies
- Department of Pathology and Laboratory MedicineUniversity of North Carolina at Chapel HillChapel HillNC
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Brosnihan KB, Hodgin JB, Smithies O, Maeda N, Gallagher P. Tissue-specific regulation of ACE/ACE2 and AT1/AT2 receptor gene expression by oestrogen in apolipoprotein E/oestrogen receptor-alpha knock-out mice. Exp Physiol 2008; 93:658-64. [PMID: 18192335 DOI: 10.1113/expphysiol.2007.041806] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Angiotensin-converting enzyme (ACE) and ACE2 and the AT1 and AT2 receptors are pivotal points of regulation in the renin-angiotensin system. ACE and ACE2 are key enzymes in the formation and degradation of angiotensin II (Ang II) and angiotensin-(1-7)(Ang-(1-7)). Ang II acts at either the AT1 or the AT2 receptor to mediate opposing actions of vasoconstriction or vasodilatation respectively. While it is known that oestrogen acts to downregulate ACE and the AT(1) receptor, its regulation of ACE2 and the AT2 receptor and the involvement of a specific oestrogen receptor subtype are unknown. To investigate the role of oestrogen receptor-alpha (ERalpha) in the regulation by oestrogen of ACE/ACE2 and AT1/AT2 mRNAs in lung and kidney, ovariectomized female mice lacking apolipoprotein E (ee) with the ERalpha (AAee) or without the ERalpha (alphaalphaee) were treated with 17beta-oestradiol (6 microg day(-1)) or placebo for 3 months. ACE, ACE2, AT1 receptor and AT2 receptor mRNAs were measured using reverse transcriptase, real-time polymerase chain reaction. In the kidney, 17beta-oestradiol showed 1.7-fold downregulation of ACE mRNA in AAee mice, with 2.1-fold upregulation of ACE mRNA in alphaalphaee mice. 17beta-Oestradiol showed 1.5- and 1.8-fold downregulation of ACE2 and AT1 receptor mRNA in AAee mice; this regulation was lost in alphaalphaee mice. 17beta-Oestradiol showed marked (81-fold) upregulation of the AT(2) receptor mRNA in AAee mice. In the lung, 17beta-oestradiol treatment had no effect on AT1 receptor mRNA in AAee mice, but resulted in a 1.5-fold decreased regulation of AT1 mRNA in alphaalphaee mice. There was no significant interaction of oestrogen with ERalpha in the lung for ACE, ACE2 and AT2 receptor genes. These studies reveal tissue-specific regulation by 17beta-oestradiol of ACE/ACE2 and AT1/AT2 receptor genes, with the ERalpha receptor being primarily responsible for the regulation of kidney ACE2, AT1 receptor and AT2 receptor genes.
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Affiliation(s)
- K Bridget Brosnihan
- The Hypertension and Vascular Disease Center, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1032, USA.
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Abstract
To study the effects of modestly increased expression of aldosterone synthase (AS), we generated mice (AS(hi/hi)) by replacing the 3' untranslated region of AS mRNA with that from a stable mRNA. AS(hi/hi) mice on a normal-salt diet had 1.5 times the wild-type AS mRNA in adrenals, although their blood pressure and plasma aldosterone did not differ from wild-type mice. Changes in dietary salt did not affect the blood pressure of wild-type mice, but AS(hi/hi) mice had approximately 10-mm Hg higher blood pressure on a high-salt diet than on a low-salt diet and than wild-type mice on either diet. The AS(hi/hi) mice on a high-salt diet also had higher plasma aldosterone, lower plasma potassium, and greater renal expression of the alpha subunit of epithelial sodium channel compared with wild-type mice. The AS(hi/hi) mice on a high-salt diet also had more water intake and urine volume and less urine osmolality than wild-type mice. On a low-salt diet, AS(hi/hi) mice maintained normal blood pressure with less activation of the renin-angiotensin-aldosterone system than wild-type mice. The AS(hi/hi) mice also had less water intake and urine volume and higher urine osmolality than wild-type mice. On a medium high-salt diet, AS(hi/hi) mice were more susceptible than wild-type mice to infusion of angiotensin II, having a higher blood pressure, greater cardiac hypertrophy, and increased oxidative stress. Thus, a modest increase in AS expression makes blood pressure more sensitive to salt, suggesting that genetically increased AS expression in humans may contribute to hypertension and cardiovascular complications in societies with high-salt diets.
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Affiliation(s)
- Natalia Makhanova
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, 701 Brinkhous-Bullitt Building, Chapel Hill, NC 27599-7525, USA
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Dackor R, Fritz-Six K, Smithies O, Caron K. Receptor Activity-modifying Proteins 2 and 3 Have Distinct Physiological Functions from Embryogenesis to Old Age. J Biol Chem 2007; 282:18094-18099. [PMID: 17470425 DOI: 10.1074/jbc.m703544200] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
RAMPs (receptor activity modifying proteins) impart remarkable effects on G protein-coupled receptor (GPCR) signaling. First identified through an interaction with the calcitonin receptor-like receptor (CLR), these single transmembrane proteins are now known to modulate the in vitro ligand binding affinity, trafficking, and second messenger pathways of numerous GPCRs. Consequently, the receptor-RAMP interface represents an attractive pharmacological target for the treatment of disease. Although the three known mammalian RAMPs differ in their sequences and tissue expression, results from in vitro biochemical and pharmacological studies suggest that they have overlapping effects on the GPCRs with which they interact. Therefore, to determine whether RAMP2 and RAMP3 have distinct functions in vivo, we generated mice with targeted deletions of either the RAMP2 or RAMP3 gene. Strikingly, we found that, although RAMP2 is required for survival, mice that lack RAMP3 appear normal until old age, at which point they have decreased weight. In addition, mice with reduced expression of RAMP2 (but not RAMP3) display remarkable subfertility. Thus, each gene has functions in vivo that cannot be accomplished by the other. Because RAMP2, RAMP3, and CLR transduce the signaling of the two potent vasodilators adrenomedullin and calcitonin gene-related peptide, we tested the effects of our genetic modifications on blood pressure, and no effects were detected. Nevertheless, our studies reveal that RAMP2 and RAMP3 have distinct physiological functions throughout embryogenesis, adulthood, and old age, and the mice we have generated provide novel genetic tools to further explore the utility of the receptor-RAMP interface as a pharmacological target.
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Affiliation(s)
- Ryan Dackor
- Department of Cell and Molecular Physiology, University of North Carolina, Chapel Hill, North Carolina 27599; Genetics Department, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Kim Fritz-Six
- Department of Cell and Molecular Physiology, University of North Carolina, Chapel Hill, North Carolina 27599; Genetics Department, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Oliver Smithies
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Kathleen Caron
- Department of Cell and Molecular Physiology, University of North Carolina, Chapel Hill, North Carolina 27599; Genetics Department, University of North Carolina, Chapel Hill, North Carolina 27599.
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Hakim ZS, DiMichele LA, Doherty JT, Homeister JW, Beggs HE, Reichardt LF, Schwartz RJ, Brackhan J, Smithies O, Mack CP, Taylor JM. Conditional deletion of focal adhesion kinase leads to defects in ventricular septation and outflow tract alignment. Mol Cell Biol 2007; 27:5352-64. [PMID: 17526730 PMCID: PMC1952084 DOI: 10.1128/mcb.00068-07] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To examine a role for focal adhesion kinase (FAK) in cardiac morphogenesis, we generated a line of mice with a conditional deletion of FAK in nkx2-5-expressing cells (herein termed FAKnk mice). FAKnk mice died shortly after birth, likely resulting from a profound subaortic ventricular septal defect and associated malalignment of the outflow tract. Additional less penetrant phenotypes included persistent truncus arteriosus and thickened valve leaflets. Thus, conditional inactivation of FAK in nkx2-5-expressing cells leads to the most common congenital heart defect that is also a subset of abnormalities associated with tetralogy of Fallot and the DiGeorge syndrome. No significant differences in proliferation or apoptosis between control and FAKnk hearts were observed. However, decreased myocardialization was observed for the conal ridges of the proximal outflow tract in FAKnk hearts. Interestingly, chemotaxis was significantly attenuated in isolated FAK-null cardiomyocytes in comparison to genetic controls, and these effects were concomitant with reduced tyrosine phosphorylation of Crk-associated substrate (CAS). Thus, it is possible that ventricular septation and appropriate outflow tract alignment is dependent, at least in part, upon FAK-dependent CAS activation and subsequent induction of polarized myocyte movement into the conal ridges. Future studies will be necessary to determine the precise contributions of the additional nkx2-5-derived lineages to the phenotypes observed.
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Affiliation(s)
- Zeenat S Hakim
- Department of Pathology and Carolina Cardiovascular Biology Center, 501 Brinkhous-Bullitt Bldg. CB 7525, University of North Carolina, Chapel Hill, NC 27599, USA
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Kakoki M, McGarrah RW, Kim HS, Smithies O. Bradykinin B1 and B2 receptors both have protective roles in renal ischemia/reperfusion injury. Proc Natl Acad Sci U S A 2007; 104:7576-81. [PMID: 17452647 PMCID: PMC1855073 DOI: 10.1073/pnas.0701617104] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
To explore the role of the kallikrein-kinin system in relation to ischemia/reperfusion injury in the kidney, we generated mice lacking both the bradykinin B1 and B2 receptor genes (B1RB2R-null, Bdkrb1-/-/Bdkrb2-/-) by deleting the genomic region encoding the two receptors. In 4-month-old mice, blood pressures were not significantly different among B1RB2R-null, B2R-null (Bdkrb2-/-), and WT mice. After 30 min of bilateral renal artery occlusion and 24 h of reperfusion, mortality rates, renal histological and functional changes, 8-hydroxy-2'-deoxyguanosine levels in total DNA, mtDNA deletions, and the number of TUNEL-positive cells in the kidneys increased progressively in the following order (from lowest to highest): WT, B2R-null, and B1RB2R-null mice. Increases in mRNA levels of TGF-beta1, connective tissue growth factor, and endothelin-1 after ischemia/reperfusion injury were also exaggerated in the same order (from lowest to highest): WT, B2R-null, and B1RB2R-null. Thus, both the B1 and B2 bradykinin receptors play an important role in reducing DNA damage, apoptosis, morphological and functional kidney changes, and mortality during renal ischemia/reperfusion injury.
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Affiliation(s)
- Masao Kakoki
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599-7525
- *To whom correspondence should be addressed. E-mail: or
| | - Robert W. McGarrah
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599-7525
| | - Hyung-Suk Kim
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599-7525
| | - Oliver Smithies
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599-7525
- *To whom correspondence should be addressed. E-mail: or
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Yamaguchi N, Takahashi N, Xu L, Smithies O, Meissner G. Early cardiac hypertrophy in mice with impaired calmodulin regulation of cardiac muscle Ca release channel. J Clin Invest 2007; 117:1344-53. [PMID: 17431507 PMCID: PMC1847534 DOI: 10.1172/jci29515] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Accepted: 02/13/2007] [Indexed: 11/17/2022] Open
Abstract
Studies with isolated membrane fractions have shown that calmodulin (CaM) inhibits the activity of cardiac muscle cell Ca(2+) release channel ryanodine receptor 2 (RyR2). To determine the physiological importance of CaM regulation of RyR2, we generated a mouse with 3 amino acid substitutions (RyR2-W3587A/L3591D/F3603A) in exon 75 of the Ryr2 gene, which encodes the CaM-binding site of RyR2. Homozygous mutant mice showed an increased ratio of heart weight to body weight, greatly reduced fractional shortening of the left ventricle, and lethality at 9-16 days of age. Biochemical analysis of hearts of 7- and 10-day-old homozygous mutant mice indicated an impaired CaM inhibition of RyR2 at micromolar Ca(2+) concentrations, reduction in RyR2 protein levels and sarcoplasmic reticulum Ca(2+) sequestration, and upregulation of genes and/or proteins associated with class II histone deacetylase/myocyte enhancer factor-2 and calcineurin signaling pathways. Sustained Ca(2+) transients, often displaying repeated periods of incomplete Ca(2+) removal, were observed in homozygous cardiomyocytes. Taken together, the data indicate that impaired CaM inhibition of RyR2, associated with defective sarcoplasmic reticulum Ca(2+) release and altered gene expression, leads to cardiac hypertrophy and early death.
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Affiliation(s)
- Naohiro Yamaguchi
- Department of Biochemistry and Biophysics and
Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Nobuyuki Takahashi
- Department of Biochemistry and Biophysics and
Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Le Xu
- Department of Biochemistry and Biophysics and
Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Oliver Smithies
- Department of Biochemistry and Biophysics and
Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Gerhard Meissner
- Department of Biochemistry and Biophysics and
Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Caron K, Hagaman J, Nishikimi T, Kim HS, Smithies O. Adrenomedullin gene expression differences in mice do not affect blood pressure but modulate hypertension-induced pathology in males. Proc Natl Acad Sci U S A 2007; 104:3420-5. [PMID: 17360661 PMCID: PMC1802008 DOI: 10.1073/pnas.0611365104] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Adrenomedullin (AM) is a potent vasodilator peptide in plasma at picomolar levels. Polymorphisms in the human AM gene have been associated with genetic predisposition to diabetic nephropathy and proteinuria with essential hypertension, and numerous studies have demonstrated that endogenous AM plays a role in protecting the heart and kidneys from fibrosis resulting from cardiovascular disease. Elevated plasma levels of AM are associated with pregnancy and sepsis and with cardiovascular stress and hypertension. However, there are no reports of the effects of genetic differences in the expression of the endogenous AM gene and of gender on blood pressure in these circumstances or on the pathological changes accompanying hypertension. To address these questions, we have generated mice having genetically controlled levels of AM mRNA ranging from approximately 50% to approximately 140% of wild-type levels. These modest changes in AM gene expression have no effect on basal blood pressure. Although pregnancy and sepsis increase plasma AM levels, genetically reducing AM production does not affect the transient hypotension that occurs during normal pregnancy or that is induced by treatment with lipopolysaccharide. Nor does the reduction of AM affect chronic hypertension caused by a renin transgene. However, 50% normal expression of AM enhances cardiac hypertrophy and renal damage in male, but not female, mice with a renin transgene. These observations suggest that the effect of gender on the role of AM in counteracting cardiovascular damage in humans merits careful evaluation.
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Affiliation(s)
- Kathleen Caron
- Department of Cell and Molecular Physiology and Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA.
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Ellmers LJ, Scott NJA, Piuhola J, Maeda N, Smithies O, Frampton CM, Richards AM, Cameron VA. Npr1-regulated gene pathways contributing to cardiac hypertrophy and fibrosis. J Mol Endocrinol 2007; 38:245-57. [PMID: 17293444 DOI: 10.1677/jme.1.02138] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The natriuretic peptides, atrial (ANP) and brain natriuretic peptide (BNP) are known to suppress cardiac hypertrophy and fibrosis. Both ANP and BNP exert their bioactivities through the Npr1 receptor, and Npr1 knockout mice (Npr1-/-) exhibit marked cardiac hypertrophy and fibrosis. In this study, we investigated which genes within the hypertrophic and fibrotic pathways are influenced by the lack of Npr1 signalling. cDNA microarray and quantitative real-time PCR (RT-PCR) analyses were performed on cardiac ventricles from Npr1-/-mice. Gene expression at early and late stages during development of hypertrophy was investigated in male and female Npr1-/-mice at 8 weeks and 6 months of age. Heart weight to body weight ratios (HW:BW) were maximally increased in 8-week males (P<0 x 01), whilst HW:BW in females continued to increase progressively up to 6 months (P<0 x 01). This was despite blood pressure being similarly elevated at both the ages in male and female knockout when compared with wild-type (WT) mice (P<0 x 001). Microarray analysis identified altered gene expression at the earliest steps in the hypertrophy-signalling cascade in Npr1-/- mice, particularly calcium-calmodulin signalling and ion channels, with subsequent changes in the expression of intracellular messengers including protein kinases and transcription factors. Real-time PCR analysis confirmed significant differences in gene expression of ANP, BNP, calmodulin 1, histone deacetylase 7a (HDAC7a), protein kinase C (PKC)iota, (GATA) 4, collagen 1, phospholamban and transforming growth factor-beta1 in Npr1-/- mice when compared with WT (P<0 x 05). The present study implicates the calmodulin-CaMK-Hdac-Mef2 and PKC-MAPK-GATA4 pathways in Npr1 mediation of cardiac hypertrophy.
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Affiliation(s)
- Leigh J Ellmers
- Christchurch Cardioendocrine Research Group, Department of Medicine, Christchurch School of Medicine and Health Sciences, PO Box 4345, Christchurch, New Zealand.
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Crowley S, Gurley S, Herrera M, Ruiz P, Griffiths R, Kumar A, Kim HS, Smithies O, Le T, Coffman T. Role of Renal Angiotensin II Type 1 Receptors in the Genesis of Hypertension: Guyton Revisited. J Am Soc Nephrol 2007. [DOI: 10.1681/asn.2006121393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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Makhanova N, Sequeira-Lopez MLS, Gomez RA, Kim HS, Smithies O. Disturbed Homeostasis in Sodium-Restricted Mice Heterozygous and Homozygous for Aldosterone Synthase Gene Disruption. Hypertension 2006; 48:1151-9. [PMID: 17075030 DOI: 10.1161/01.hyp.0000249902.09036.e7] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have determined that differences in expression of aldosterone synthase (AS) affect responses to a low-salt diet. In AS-null mice (AS(-/-)), but not in wild-type, low salt significantly decreased plasma sodium and increased potassium. The increased urine volume (1.5xwild-type) and decreased urine osmolality (0.7xwild-type), present in AS(-/-) mice on normal salt, became more severe (2.3xwild-type and 0.5xwild-type) on low salt, but neither changed in wild-type. In both genotypes, plasma vasopressin was similar on normal and low salt, and desmopressin injection significantly increased urine osmolality. Renal mRNA levels for aquaporin 1 and 3 were unchanged by genotype or diet and epithelial sodium channel and Na(+)-K(+)-2Cl(-)-cotransporter by genotype. In AS(-/-) mice, aquaporin 2 mRNA increased on normal salt, whereas Na(+)Cl(-)-cotransporter and cortex K(+) channel mRNAs decreased on both diets. The low blood pressure of AS(-/-) mice was decreased further by low salt, despite additional increases in renin, intrarenal arterial wall thickness, and macula densa cyclogenase-2 mRNA. In AS(+/-) mice on normal salt, adrenal AS mRNA was slightly decreased (0.7xwild-type), but blood pressure was normal. On low salt, their blood pressure was less than wild-type (101+/-2 mm Hg versus 106+/-2 mm Hg), even though renin mRNA increased to 2xwild-type. We conclude that aldosterone is critical for urine concentration and maintenance of blood pressure and even a mild reduction of AS expression makes blood pressure sensitive to low salt, suggesting that genetic differences of AS levels in humans may influence how blood pressure responds to dietary salt.
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Affiliation(s)
- Natalia Makhanova
- Department of Pathology and Laboratory Medicine, University of Virginia, Charlottesville, USA
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Crowley SD, Gurley SB, Herrera MJ, Ruiz P, Griffiths R, Kumar AP, Kim HS, Smithies O, Le TH, Coffman TM. Angiotensin II causes hypertension and cardiac hypertrophy through its receptors in the kidney. Proc Natl Acad Sci U S A 2006; 103:17985-90. [PMID: 17090678 PMCID: PMC1693859 DOI: 10.1073/pnas.0605545103] [Citation(s) in RCA: 516] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Essential hypertension is a common disease, yet its pathogenesis is not well understood. Altered control of sodium excretion in the kidney may be a key causative feature, but this has been difficult to test experimentally, and recent studies have challenged this hypothesis. Based on the critical role of the renin-angiotensin system (RAS) and the type I (AT1) angiotensin receptor in essential hypertension, we developed an experimental model to separate AT1 receptor pools in the kidney from those in all other tissues. Although actions of the RAS in a variety of target organs have the potential to promote high blood pressure and end-organ damage, we show here that angiotensin II causes hypertension primarily through effects on AT1 receptors in the kidney. We find that renal AT1 receptors are absolutely required for the development of angiotensin II-dependent hypertension and cardiac hypertrophy. When AT1 receptors are eliminated from the kidney, the residual repertoire of systemic, extrarenal AT1 receptors is not sufficient to induce hypertension or cardiac hypertrophy. Our findings demonstrate the critical role of the kidney in the pathogenesis of hypertension and its cardiovascular complications. Further, they suggest that the major mechanism of action of RAS inhibitors in hypertension is attenuation of angiotensin II effects in the kidney.
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Affiliation(s)
- Steven D. Crowley
- *Department of Medicine, Duke University Medical Center and Durham Veterans Affairs Medical Center, Durham, NC 27710
| | - Susan B. Gurley
- *Department of Medicine, Duke University Medical Center and Durham Veterans Affairs Medical Center, Durham, NC 27710
| | - Maria J. Herrera
- *Department of Medicine, Duke University Medical Center and Durham Veterans Affairs Medical Center, Durham, NC 27710
| | - Phillip Ruiz
- Department of Pathology, University of Miami, Miami, FL 33136; and
| | - Robert Griffiths
- *Department of Medicine, Duke University Medical Center and Durham Veterans Affairs Medical Center, Durham, NC 27710
| | - Anil P. Kumar
- *Department of Medicine, Duke University Medical Center and Durham Veterans Affairs Medical Center, Durham, NC 27710
| | - Hyung-Suk Kim
- Department of Pathology, University of North Carolina, Chapel Hill, NC 27599
| | - Oliver Smithies
- Department of Pathology, University of North Carolina, Chapel Hill, NC 27599
| | - Thu H. Le
- *Department of Medicine, Duke University Medical Center and Durham Veterans Affairs Medical Center, Durham, NC 27710
| | - Thomas M. Coffman
- *Department of Medicine, Duke University Medical Center and Durham Veterans Affairs Medical Center, Durham, NC 27710
- To whom correspondence should be addressed at:
Duke University Medical Center, Box 3014, Durham, NC 27710. E-mail:
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Pandya K, Kim HS, Smithies O. Fibrosis, not cell size, delineates beta-myosin heavy chain reexpression during cardiac hypertrophy and normal aging in vivo. Proc Natl Acad Sci U S A 2006; 103:16864-9. [PMID: 17068123 PMCID: PMC1624863 DOI: 10.1073/pnas.0607700103] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Reexpression of the fetally expressed beta-myosin heavy chain (beta-MHC) gene is a well documented marker of pathological cardiac hypertrophy and normal aging in many experimental models. To gain insights into factors affecting this reexpression of beta-MHC within the complex anatomical structure of the heart, we investigated the spatial pattern of its expression at the level of single cells during aging and hypertrophy. We generated mice that express yellow fluorescent protein fused to the N terminus of the beta-MHC and examined its expression pattern during normal aging and in mice with hypertrophy induced by constitutive expression of a renin transgene. The localization of fibrosis within the hearts also was determined by using a fluorescent lectin. The results show that reexpression of beta-MHC occurs in discrete subsets of myocytes within the subendocardium rather than uniformly throughout the heart, that beta-MHC induction is not an obligatory consequence of cellular hypertrophy, and that beta-MHC-expressing cells in the normal aging heart and the hypertrophic heart are distributed predominantly in clusters within and surrounding foci of fibrosis. We conclude that beta-MHC gene expression in the normal aging adult and hypertrophic mouse heart is a marker of fibrosis rather than of cellular hypertrophy.
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Affiliation(s)
- Kumar Pandya
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599
| | - Hyung-Suk Kim
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599
| | - Oliver Smithies
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599
- *To whom correspondence should be addressed at:
Department of Pathology and Laboratory Medicine, University of North Carolina, 701 Brinkhous Bullit Building, Chapel Hill, NC 27599-7525. E-mail:
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Li M, Yee D, Magnuson TR, Smithies O, Caron KM. Reduced maternal expression of adrenomedullin disrupts fertility, placentation, and fetal growth in mice. J Clin Invest 2006; 116:2653-62. [PMID: 16981008 PMCID: PMC1564429 DOI: 10.1172/jci28462] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Accepted: 07/26/2006] [Indexed: 01/16/2023] Open
Abstract
Adrenomedullin (AM) is a multifunctional peptide vasodilator that is essential for life. Plasma AM expression dramatically increases during pregnancy, and alterations in its levels are associated with complications of pregnancy including fetal growth restriction (FGR) and preeclampsia. Using AM+/- female mice with genetically reduced AM expression, we demonstrate that fetal growth and placental development are seriously compromised by this modest decrease in expression. AM+/- female mice had reduced fertility characterized by FGR. The incidence of FGR was also influenced by the genotype of the embryo, since AM-/- embryos were more often affected than either AM+/- or AM+/+ embryos. We demonstrate that fetal trophoblast cells and the maternal uterine wall have coordinated and localized increases in AM gene expression at the time of implantation. Placentas from growth-restricted embryos showed defects in trophoblast cell invasion, similar to defects that underlie human preeclampsia and placenta accreta. Our data provide a genetic in vivo model to implicate both maternal and, to a lesser extent, embryonic levels of AM in the processes of implantation, placentation, and subsequent fetal growth. This study provides the first genetic evidence to our knowledge to suggest that a modest reduction in human AM expression during pregnancy may have an unfavorable impact on reproduction.
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Affiliation(s)
- Manyu Li
- Department of Cell and Molecular Physiology,
Department of Genetics, and
Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Della Yee
- Department of Cell and Molecular Physiology,
Department of Genetics, and
Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Terry R. Magnuson
- Department of Cell and Molecular Physiology,
Department of Genetics, and
Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Oliver Smithies
- Department of Cell and Molecular Physiology,
Department of Genetics, and
Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Kathleen M. Caron
- Department of Cell and Molecular Physiology,
Department of Genetics, and
Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Yasuda O, Fukuo K, Sun X, Nishitani M, Yotsui T, Higuchi M, Suzuki T, Rakugi H, Smithies O, Maeda N, Ogihara T. Apop-1, a novel protein inducing cyclophilin D-dependent but Bax/Bak-related channel-independent apoptosis. J Biol Chem 2006; 281:23899-907. [PMID: 16782708 DOI: 10.1074/jbc.m512610200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the intrinsic pathway of apoptosis, mitochondria play a crucial role by releasing cytochrome c from the intermembrane space into the cytoplasm. Cytochrome c release through Bax/Bak-dependent channels in mitochondria has been well documented. In contrast, cyclophilin D (CypD), an important component of permeability transition pore-dependent protein release, remains largely undefined, and no apoptogenic proteins that act specifically in a CypD-dependent manner have been reported to date. Here, we describe a novel and evolutionarily conserved protein, apoptogenic protein (Apop). Mouse Apop-1 expression induces apoptotic death by releasing cytochrome c from mitochondria into the cytosolic space followed by activation of caspase-9 and -3. Apop-1-induced apoptosis is not blocked by Bcl-2 or Bcl-xL, inhibitors of Bax/Bak-dependent channels, whereas it is completely blocked by cyclosporin A, an inhibitor of permeability transition pore. Cells lacking CypD were resistant to Apop-induced apoptosis. Moreover, inhibition of Apop expression prevented the cell death induced by apoptosis-inducing substances. Our findings, thus, indicate that the expression of Apop-1 induces apoptosis though CypD-dependent pathway and that Apop-1 plays roles in cell death under physiological conditions.
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Affiliation(s)
- Osamu Yasuda
- Department of Geriatric Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
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Abstract
To examine the mechanisms whereby amino acids modulate nitric oxide (NO) production and blood flow in the renal vasculature, chemiluminescence techniques were used to quantify NO in the renal venous effluent of the isolated, perfused rat kidney as different amino acids were added to the perfusate. The addition of 10−4or 10−3M cationic amino acids (l-ornithine, l-lysine, or l-homoarginine) or neutral amino acids (l-glutamine, l-leucine, or l-serine) to the perfusate decreased NO and increased renal vascular resistance. Perfusion with anionic amino acids (l-glutamate or l-aspartate) had no effect on either parameter. The effects of the cationic and neutral amino acids were reversed with 10−3M l-arginine and prevented by deendothelialization or NO synthase inhibition. The effects of the neutral amino acids but not the cationic amino acids were dependent on extracellular sodium. Cationic and neutral amino acids also decreased calcimycin-induced NO, as assessed by DAF-FM-T fluorescence, in cultured EA.hy926 endothelial cells. Inhibition of system y+or y+L by siRNA for the cationic amino acid transporter 1 or the CD98/4F2 heavy chain diminished the NO-depleting effects of these amino acids. Finally, transport studies in cultured cells demonstrated that cationic or neutral amino acids in the extracellular space stimulate efflux of l-arginine out of the cell. Thus the present experiments demonstrate that cationic and neutral amino acids can modulate NO production in endothelial cells by altering cellular l-arginine transport through y+and y+L transport mechanisms.
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Affiliation(s)
- Masao Kakoki
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, USA
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50
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Perrino C, Prasad SVN, Mao L, Noma T, Yan Z, Kim HS, Smithies O, Rockman HA. Intermittent pressure overload triggers hypertrophy-independent cardiac dysfunction and vascular rarefaction. J Clin Invest 2006; 116:1547-60. [PMID: 16741575 PMCID: PMC1464895 DOI: 10.1172/jci25397] [Citation(s) in RCA: 188] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2005] [Accepted: 03/21/2006] [Indexed: 02/06/2023] Open
Abstract
For over a century, there has been intense debate as to the reason why some cardiac stresses are pathological and others are physiological. One long-standing theory is that physiological overloads such as exercise are intermittent, while pathological overloads such as hypertension are chronic. In this study, we hypothesized that the nature of the stress on the heart, rather than its duration, is the key determinant of the maladaptive phenotype. To test this, we applied intermittent pressure overload on the hearts of mice and tested the roles of duration and nature of the stress on the development of cardiac failure. Despite a mild hypertrophic response, preserved systolic function, and a favorable fetal gene expression profile, hearts exposed to intermittent pressure overload displayed pathological features. Importantly, intermittent pressure overload caused diastolic dysfunction, altered beta-adrenergic receptor (betaAR) function, and vascular rarefaction before the development of cardiac hypertrophy, which were largely normalized by preventing the recruitment of PI3K by betaAR kinase 1 to ligand-activated receptors. Thus stress-induced activation of pathogenic signaling pathways, not the duration of stress or the hypertrophic growth per se, is the molecular trigger of cardiac dysfunction.
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Affiliation(s)
- Cinzia Perrino
- Duke University Medical Center, Durham, North Carolina, USA.
University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA
| | - Sathyamangla V. Naga Prasad
- Duke University Medical Center, Durham, North Carolina, USA.
University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA
| | - Lan Mao
- Duke University Medical Center, Durham, North Carolina, USA.
University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA
| | - Takahisa Noma
- Duke University Medical Center, Durham, North Carolina, USA.
University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA
| | - Zhen Yan
- Duke University Medical Center, Durham, North Carolina, USA.
University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA
| | - Hyung-Suk Kim
- Duke University Medical Center, Durham, North Carolina, USA.
University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA
| | - Oliver Smithies
- Duke University Medical Center, Durham, North Carolina, USA.
University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA
| | - Howard A. Rockman
- Duke University Medical Center, Durham, North Carolina, USA.
University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA
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