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Garfa Traoré M, Roccio F, Miceli C, Ferri G, Parisot M, Cagnard N, Lhomme M, Dupont N, Benmerah A, Saunier S, Delous M. Fluid shear stress triggers cholesterol biosynthesis and uptake in inner medullary collecting duct cells, independently of nephrocystin-1 and nephrocystin-4. Front Mol Biosci 2023; 10:1254691. [PMID: 37916190 PMCID: PMC10616263 DOI: 10.3389/fmolb.2023.1254691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 09/15/2023] [Indexed: 11/03/2023] Open
Abstract
Renal epithelial cells are subjected to fluid shear stress of urine flow. Several cellular structures act as mechanosensors-the primary cilium, microvilli and cell adhesion complexes-that directly relay signals to the cytoskeleton to regulate various processes including cell differentiation and renal cell functions. Nephronophthisis (NPH) is an autosomal recessive tubulointerstitial nephropathy leading to end-stage kidney failure before adulthood. NPHP1 and NPHP4 are the major genes which code for proteins that form a complex at the transition zone of the primary cilium, a crucial region required for the maintenance of the ciliary composition integrity. These two proteins also interact with signaling components and proteins associated with the actin cytoskeleton at cell junctions. Due to their specific subcellular localization, we wondered whether NPHP1 and NPHP4 could ensure mechanosensory functions. Using a microfluidic set up, we showed that murine inner medullary collecting ductal cells invalidated for Nphp1 or Nphp4 are more responsive to immediate shear exposure with a fast calcium influx, and upon a prolonged shear condition, an inability to properly regulate cilium length and actin cytoskeleton remodeling. Following a transcriptomic study highlighting shear stress-induced gene expression changes, we showed that prolonged shear triggers both cholesterol biosynthesis pathway and uptake, processes that do not seem to involve neither NPHP1 nor NPHP4. To conclude, our study allowed us to determine a moderate role of NPHP1 and NPHP4 in flow sensation, and to highlight a new signaling pathway induced by shear stress, the cholesterol biosynthesis and uptake pathways, which would allow cells to cope with mechanical stress by strengthening their plasma membrane through the supply of cholesterol.
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Affiliation(s)
- Meriem Garfa Traoré
- Laboratory of Hereditary Kidney Disease, INSERM UMR 1163, Imagine Institute, Université Paris Cité, Paris, France
- Cell Imaging Platform, Structure Fédérative de Recherche Necker, INSERM US24/CNRS UMS3633, Université Paris Cité, Paris, France
| | - Federica Roccio
- Institut Necker Enfants-Malades (INEM), INSERM U1151/CNRS UMR 8253, Université Paris Cité, Paris, France
| | - Caterina Miceli
- Institut Necker Enfants-Malades (INEM), INSERM U1151/CNRS UMR 8253, Université Paris Cité, Paris, France
| | - Giulia Ferri
- Laboratory of Hereditary Kidney Disease, INSERM UMR 1163, Imagine Institute, Université Paris Cité, Paris, France
| | - Mélanie Parisot
- Genomics Core Facility, Institut Imagine-Structure Fédérative de Recherche Necker, INSERM U1163 et INSERM US24/CNRS UMS3633, Université Paris Cité, Paris, France
| | - Nicolas Cagnard
- Bioinformatic Platform, Institut Imagine-Structure Fédérative de Recherche Necker, INSERM U1163 et INSERM US24/CNRS UMS3633, Université Paris Cité, Paris, France
| | - Marie Lhomme
- ICAN Omics, IHU ICAN Foundation for Innovation in Cardiometabolism and Nutrition, Pitié-Salpêtrière Hospital, Paris, France
| | - Nicolas Dupont
- Institut Necker Enfants-Malades (INEM), INSERM U1151/CNRS UMR 8253, Université Paris Cité, Paris, France
| | - Alexandre Benmerah
- Laboratory of Hereditary Kidney Disease, INSERM UMR 1163, Imagine Institute, Université Paris Cité, Paris, France
| | - Sophie Saunier
- Laboratory of Hereditary Kidney Disease, INSERM UMR 1163, Imagine Institute, Université Paris Cité, Paris, France
| | - Marion Delous
- Laboratory of Hereditary Kidney Disease, INSERM UMR 1163, Imagine Institute, Université Paris Cité, Paris, France
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Sadri S, Tomar N, Yang C, Audi SH, Cowley AW, Dash RK. Effects of ROS pathway inhibitors and NADH and FADH 2 linked substrates on mitochondrial bioenergetics and ROS emission in the heart and kidney cortex and outer medulla. Arch Biochem Biophys 2023; 744:109690. [PMID: 37429534 PMCID: PMC10528392 DOI: 10.1016/j.abb.2023.109690] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 07/06/2023] [Indexed: 07/12/2023]
Abstract
Mitochondria are major sources of reactive oxygen species (ROS), which play important roles in both physiological and pathological processes. However, the specific contributions of different ROS production and scavenging components in the mitochondria of metabolically active tissues such as heart and kidney cortex and outer medulla (OM) are not well understood. Therefore, the goal of this study was to determine contributions of different ROS production and scavenging components and provide detailed comparisons of mitochondrial respiration, bioenergetics, ROS emission between the heart and kidney cortex and OM using tissues obtained from the same Sprague-Dawley rat under identical conditions and perturbations. Specifically, data were obtained using both NADH-linked substrate pyruvate + malate and FADH2-linked substrate succinate followed by additions of inhibitors of different components of the electron transport chain (ETC) and oxidative phosphorylation (OxPhos) and other ROS production and scavenging systems. Currently, there is limited data available for the mitochondria of kidney cortex and OM, the two major energy-consuming tissues in the body only next to the heart, and scarce quantitative information on the interplay between mitochondrial ROS production and scavenging systems in the three tissues. The findings from this study demonstrate significant differences in mitochondrial respiratory and bioenergetic functions and ROS emission among the three tissues. The results quantify the rates of ROS production from different complexes of the ETC, identify the complexes responsible for variations in mitochondrial membrane depolarization and regulations of ROS production, and quantify the contributions of ROS scavenging enzymes towards overall mitochondrial ROS emission. These findings advance our fundamental knowledge of tissue-specific and substrate-dependent mitochondrial respiratory and bioenergetic functions and ROS emission. This is important given the critical role that excess ROS production, oxidative stress, and mitochondrial dysfunction in the heart and kidney cortex and OM play in the pathogenesis of cardiovascular and renal diseases, including salt-sensitive hypertension.
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Affiliation(s)
- Shima Sadri
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Namrata Tomar
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Chun Yang
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Said H Audi
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, 53226, USA; Department of Biomedical Engineering, Marquette University, Milwaukee, WI, 53223, USA
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA; Cardiovascular Research Center, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Ranjan K Dash
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, 53226, USA; Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA; Cardiovascular Research Center, Medical College of Wisconsin, Milwaukee, WI, 53226, USA; Department of Biomedical Engineering, Marquette University, Milwaukee, WI, 53223, USA.
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Shimada S, Hoffmann BR, Yang C, Kurth T, Greene AS, Liang M, Dash RK, Cowley AW. Metabolic Responses of Normal Rat Kidneys to a High Salt Intake. FUNCTION 2023; 4:zqad031. [PMID: 37575482 PMCID: PMC10413938 DOI: 10.1093/function/zqad031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 06/06/2023] [Accepted: 06/12/2023] [Indexed: 08/15/2023] Open
Abstract
In this study, novel methods were developed, which allowed continuous (24/7) measurement of arterial blood pressure and renal blood flow in freely moving rats and the intermittent collection of arterial and renal venous blood to estimate kidney metabolic fluxes of O2 and metabolites. Specifically, the study determined the effects of a high salt (HS; 4.0% NaCl) diet upon whole kidney O2 consumption and arterial and renal venous plasma metabolomic profiles of normal Sprague-Dawley rats. A separate group of rats was studied to determine changes in the cortex and outer medulla tissue metabolomic and mRNAseq profiles before and following the switch from a 0.4% to 4.0% NaCl diet. In addition, targeted mRNA expression analysis of cortical segments was performed. Significant changes in the metabolomic and transcriptomic profiles occurred with feeding of the HS diet. A progressive increase of kidney O2 consumption was found despite a reduction in expression of most of the mRNA encoding enzymes of TCA cycle. A novel finding was the increased expression of glycolysis-related genes in Cx and isolated proximal tubular segments in response to an HS diet, consistent with increased release of pyruvate and lactate from the kidney to the renal venous blood. Data suggests that aerobic glycolysis (eg, Warburg effect) may contribute to energy production under these circumstances. The study provides evidence that kidney metabolism responds to an HS diet enabling enhanced energy production while protecting from oxidative stress and injury. Metabolomic and transcriptomic analysis of kidneys of Sprague-Dawley rats fed a high salt diet.
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Affiliation(s)
- Satoshi Shimada
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Brian R Hoffmann
- Mass Spectrometry and Protein Chemistry, Protein Sciences, The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Chun Yang
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Theresa Kurth
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Andrew S Greene
- Mass Spectrometry and Protein Chemistry, Protein Sciences, The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Mingyu Liang
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Ranjan K Dash
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Department of Biomedical Engineering, Medical College of Wisconsin and Marquette University, Milwaukee, WI 53226, USA
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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Chivers JM, Whiles SA, Miles CB, Biederman BE, Ellison MF, Lovingood CW, Wright MH, Hoover DB, Raafey MA, Youngberg GA, Venkatachalam MA, Zheleznova NN, Yang C, Liu P, Kriegel AJ, Cowley AW, O'Connor PM, Picken MM, Polichnowski AJ. Brown-Norway chromosome 1 mitigates the upregulation of proinflammatory pathways in mTAL cells and subsequent age-related CKD in Dahl SS/JrHsdMcwi rats. Am J Physiol Renal Physiol 2023; 324:F193-F210. [PMID: 36475869 PMCID: PMC9886360 DOI: 10.1152/ajprenal.00145.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 11/23/2022] [Accepted: 11/25/2022] [Indexed: 12/13/2022] Open
Abstract
Chronic kidney disease (CKD) has a strong genetic component; however, the underlying pathways are not well understood. Dahl salt-sensitive (SS)/Jr rats spontaneously develop CKD with age and are used to investigate the genetic determinants of CKD. However, there are currently several genetically diverse Dahl SS rats maintained at various institutions and the extent to which some exhibit age-related CKD is unclear. We assessed glomerulosclerosis (GS) and tubulointerstitial fibrosis (TIF) in 3- and 6-mo-old male and female SS/JrHsdMcwi, BN/NHsd/Mcwi [Brown-Norway (BN)], and consomic SS-Chr 1BN/Mcwi (SS.BN1) rats, in which chromosome 1 from the BN rat was introgressed into the genome of the SS/JrHsdMcwi rat. Rats were fed a 0.4% NaCl diet. GS (31 ± 3% vs. 7 ± 1%) and TIF (2.3 ± 0.2 vs. 0.5 ± 0.1) were significantly greater in 6-mo-old compared with 3-mo-old SS/JrHsdMcwi rats, and CKD was exacerbated in males. GS was minimal in 6- and 3-mo-old BN (3.9 ± 0.6% vs. 1.2 ± 0.4%) and SS.BN1 (2.4 ± 0.5% vs. 1.0 ± 0.3%) rats, and neither exhibited TIF. In SS/JrHsdMcwi and SS.BN1 rats, mean arterial blood pressure was significantly greater in 6-mo-old compared with 3-mo-old SS/JrHsdMcwi (162 ± 4 vs. 131 ± 2 mmHg) but not SS.BN1 (115 ± 2 vs. 116 ± 1 mmHg) rats. In 6-mo-old SS/JrHsdMcwi rats, blood pressure was significantly greater in females. RNA-sequencing analysis revealed that inflammatory pathways were upregulated in isolated medullary thick ascending tubules in 7-wk-old SS/JrHsdMcwi rats, before the development of tubule pathology, compared with SS.BN1 rats. In summary, SS/JrHsdMcwi rats exhibit robust age-related progression of medullary thick ascending limb abnormalities, CKD, and hypertension, and gene(s) on chromosome 1 have a major pathogenic role in such changes.NEW & NOTEWORTHY This study shows that the robust age-related progression of kidney disease in Dahl SS/JrHsdMcw rats maintained on a normal-salt diet is abolished in consomic SS.BN1 rats. Evidence that medullary thick ascending limb segments of SS/JrHsdMcw rats are structurally abnormal and enriched in proinflammatory pathways before the development of protein casts provides new insights into the pathogenesis of kidney disease in this model.
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Affiliation(s)
- Jacqueline M Chivers
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
| | - Shannon A Whiles
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
| | - Conor B Miles
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
| | - Brianna E Biederman
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
| | - Megan F Ellison
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
| | - Connor W Lovingood
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
| | - Marie H Wright
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
| | - Donald B Hoover
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
- Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, Tennessee
| | - Muhammad A Raafey
- Department of Pathology, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | - George A Youngberg
- Department of Pathology, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | | | | | - Chun Yang
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Pengyuan Liu
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Alison J Kriegel
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Paul M O'Connor
- Department of Physiology, Augusta University, Augusta, Georgia
| | - Maria M Picken
- Department of Pathology, Loyola University Medical Center, Maywood, Illinois
| | - Aaron J Polichnowski
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
- Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, Tennessee
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Escada-Rebelo S, Cristo MI, Ramalho-Santos J, Amaral S. Mitochondria-Targeted Compounds to Assess and Improve Human Sperm Function. Antioxid Redox Signal 2022; 37:451-480. [PMID: 34847742 DOI: 10.1089/ars.2021.0238] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Significance: Currently 10%-15% of couples in reproductive age face infertility issues. More importantly, male factor contributes to 50% of these cases (either alone or in combination with female causes). Among various reasons, impaired sperm function is the main cause for male infertility. Furthermore, mitochondrial dysfunction and oxidative stress due to increased reactive oxygen species (ROS) production, particularly of mitochondrial origin, are believed to be the main contributors. Recent Advances: Mitochondrial dysfunction, particularly due to increased ROS production, has often been linked to impaired sperm function/quality. For decades, different methods and approaches have been developed to assess mitochondrial features that might correlate with sperm functionality. This connection is now completely accepted, with mitochondrial functionality assessment used more commonly as a readout of sperm functionality. More recently, mitochondria-targeted compounds are on the frontline for both assessment and therapeutic approaches. Critical Issues: In this review, we summarize the current methods for assessing key mitochondrial parameters known to reflect sperm quality as well as therapeutic strategies using mitochondria-targeted antioxidants aiming to improve sperm function in various situations, particularly after sperm cryopreservation. Future Directions: Although more systematic research is needed, mitochondria-targeted compounds definitely represent a promising tool to assess as well as to protect and improve sperm function. Antioxid. Redox Signal. 37, 451-480.
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Affiliation(s)
- Sara Escada-Rebelo
- PhD Programme in Experimental Biology and Biomedicine, Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Biology of Reproduction and Stem Cell Group, Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,IIIUC - Institute for Interdisciplinary Research, Casa Costa Alemão, University of Coimbra, Coimbra, Portugal
| | - Maria Inês Cristo
- Biology of Reproduction and Stem Cell Group, Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - João Ramalho-Santos
- Biology of Reproduction and Stem Cell Group, Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Sandra Amaral
- Biology of Reproduction and Stem Cell Group, Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,IIIUC - Institute for Interdisciplinary Research, Casa Costa Alemão, University of Coimbra, Coimbra, Portugal
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Grigorova YN, Juhasz O, Long JM, Zernetkina VI, Hall ML, Wei W, Morrell CH, Petrashevskaya N, Morrow A, LaNasa KH, Bagrov AY, Rapp PR, Lakatta EG, Fedorova OV. Effect of Cardiotonic Steroid Marinobufagenin on Vascular Remodeling and Cognitive Impairment in Young Dahl-S Rats. Int J Mol Sci 2022; 23:4563. [PMID: 35562955 PMCID: PMC9101263 DOI: 10.3390/ijms23094563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 04/17/2022] [Accepted: 04/17/2022] [Indexed: 02/04/2023] Open
Abstract
The hypertensive response in Dahl salt-sensitive (DSS) rats on a high-salt (HS) diet is accompanied by central arterial stiffening (CAS), a risk factor for dementia, and heightened levels of a prohypertensive and profibrotic factor, the endogenous Na/K-ATPase inhibitor marinobufagenin (MBG). We studied the effect of the in vivo administration of MBG or HS diet on blood pressure (BP), CAS, and behavioral function in young DSS rats and normotensive Sprague-Dawley rats (SD), the genetic background for DSS rats. Eight-week-old male SD and DSS rats were given an HS diet (8% NaCl, n = 18/group) or a low-salt diet (LS; 0.1% NaCl, n = 14-18/group) for 8 weeks or MBG (50 µg/kg/day, n = 15-18/group) administered via osmotic minipumps for 4 weeks in the presence of the LS diet. The MBG-treated groups received the LS diet. The systolic BP (SBP); the aortic pulse wave velocity (aPWV), a marker of CAS; MBG levels; spatial memory, measured by a water maze task; and tissue collection for the histochemical analysis were assessed at the end of the experiment. DSS-LS rats had higher SBP, higher aPWV, and poorer spatial memory than SD-LS rats. The administration of stressors HS and MBG increased aPWV, SBP, and aortic wall collagen abundance in both strains vs. their LS controls. In SD rats, HS or MBG administration did not affect heart parameters, as assessed by ECHO vs. the SD-LS control. In DSS rats, impaired whole-heart structure and function were observed after HS diet administration in DSS-HS vs. DSS-LS rats. MBG treatment did not affect the ECHO parameters in DSS-MBG vs. DSS-LS rats. The HS diet led to an increase in endogenous plasma and urine MBG levels in both SD and DSS groups. Thus, the prohypertensive and profibrotic effect of HS diet might be partially attributed to an increase in MBG. The prohypertensive and profibrotic functions of MBG were pronounced in both DSS and SD rats, although quantitative PCR revealed that different profiles of profibrotic genes in DSS and SD rats was activated after MBG or HS administration. Spatial memory was not affected by HS diet or MBG treatment in either SD or DSS rats. Impaired cognitive function was associated with higher BP, CAS, and cardiovascular remodeling in young DSS-LS rats, as compared to young SD-LS rats. MBG and HS had similar effects on the cardiovascular system and its function in DSS and SD rats, although the rate of change in SD rats was lower than in DSS rats. The absence of a cumulative effect of increased aPWV and BP on spatial memory can be explained by the cerebrovascular and brain plasticity in young rats, which help the animals to tolerate CAS elevated by HS and MBG and to counterbalance the profibrotic effect of heightened MBG.
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Affiliation(s)
- Yulia N. Grigorova
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD 21224, USA; (Y.N.G.); (O.J.); (V.I.Z.); (M.L.H.); (W.W.); (C.H.M.); (N.P.); (A.Y.B.); (E.G.L.)
| | - Ondrej Juhasz
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD 21224, USA; (Y.N.G.); (O.J.); (V.I.Z.); (M.L.H.); (W.W.); (C.H.M.); (N.P.); (A.Y.B.); (E.G.L.)
| | - Jeffrey M. Long
- Laboratory of Behavioral Neuroscience, Neurocognitive Aging Section, National Institute on Aging, NIH, Baltimore, MD 21224, USA; (J.M.L.); (A.M.); (K.H.L.); (P.R.R.)
| | - Valentina I. Zernetkina
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD 21224, USA; (Y.N.G.); (O.J.); (V.I.Z.); (M.L.H.); (W.W.); (C.H.M.); (N.P.); (A.Y.B.); (E.G.L.)
| | - Mikayla L. Hall
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD 21224, USA; (Y.N.G.); (O.J.); (V.I.Z.); (M.L.H.); (W.W.); (C.H.M.); (N.P.); (A.Y.B.); (E.G.L.)
| | - Wen Wei
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD 21224, USA; (Y.N.G.); (O.J.); (V.I.Z.); (M.L.H.); (W.W.); (C.H.M.); (N.P.); (A.Y.B.); (E.G.L.)
| | - Christopher H. Morrell
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD 21224, USA; (Y.N.G.); (O.J.); (V.I.Z.); (M.L.H.); (W.W.); (C.H.M.); (N.P.); (A.Y.B.); (E.G.L.)
| | - Natalia Petrashevskaya
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD 21224, USA; (Y.N.G.); (O.J.); (V.I.Z.); (M.L.H.); (W.W.); (C.H.M.); (N.P.); (A.Y.B.); (E.G.L.)
| | - Audrey Morrow
- Laboratory of Behavioral Neuroscience, Neurocognitive Aging Section, National Institute on Aging, NIH, Baltimore, MD 21224, USA; (J.M.L.); (A.M.); (K.H.L.); (P.R.R.)
| | - Katherine H. LaNasa
- Laboratory of Behavioral Neuroscience, Neurocognitive Aging Section, National Institute on Aging, NIH, Baltimore, MD 21224, USA; (J.M.L.); (A.M.); (K.H.L.); (P.R.R.)
| | - Alexei Y. Bagrov
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD 21224, USA; (Y.N.G.); (O.J.); (V.I.Z.); (M.L.H.); (W.W.); (C.H.M.); (N.P.); (A.Y.B.); (E.G.L.)
| | - Peter R. Rapp
- Laboratory of Behavioral Neuroscience, Neurocognitive Aging Section, National Institute on Aging, NIH, Baltimore, MD 21224, USA; (J.M.L.); (A.M.); (K.H.L.); (P.R.R.)
| | - Edward G. Lakatta
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD 21224, USA; (Y.N.G.); (O.J.); (V.I.Z.); (M.L.H.); (W.W.); (C.H.M.); (N.P.); (A.Y.B.); (E.G.L.)
| | - Olga V. Fedorova
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD 21224, USA; (Y.N.G.); (O.J.); (V.I.Z.); (M.L.H.); (W.W.); (C.H.M.); (N.P.); (A.Y.B.); (E.G.L.)
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Zheleznova NN, Kumar V, Kurth T, Cowley AW. Hydrogen peroxide (H 2O 2) mediated activation of mTORC2 increases intracellular Na + concentration in the renal medullary thick ascending limb of Henle. Sci Rep 2021; 11:7300. [PMID: 33790341 PMCID: PMC8012714 DOI: 10.1038/s41598-021-86678-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 03/05/2021] [Indexed: 11/22/2022] Open
Abstract
Hydrogen peroxide (H2O2) production in the renal outer medulla is an important determinant of renal medullary blood flow and blood pressure (BP) salt-sensitivity in Dahl salt-sensitive (SS) rats. The mechanisms and pathways responsible for these actions are poorly understood. Recently, we have discovered that the mTOR complex 2 (mTORC2) plays a critical role in BP salt-sensitivity of SS rats by regulating Na+ homeostasis. PP242, an inhibitor of mTORC1/2 pathways exhibits potent natriuretic actions and completely prevented salt-induced hypertension in SS rats. In the present study, we have found that chronic infusion of H2O2 into the single remaining kidney of Sprague Dawley (SD) rats (3 days) stimulated the functional marker (pAKTSer473/AKT) of mTORC2 activity measured by Western Blot analysis. No changes in mTORC1 activity in OM were observed as determined by pS6Ser235/236/S6. Using fluorescent microscopy and the Na+ sensitive dye Sodium Green, we have shown that H2O2 (100 µM added in the bath) increased intracellular sodium concentration ([Na+]i) in renal medullary thick ascending limbs (mTALs) isolated from SD rats. These responses were almost completely abolished by pretreatment of mTAL with 10 µM PP242, indicating that mTORC1/2 pathways were involved in the H2O2 induced increase of [Na+]i. mTAL cell volume remained unchanged (± 1%) by H2O2 as determined by 3D reconstruction confocal laser scanning microscopy techniques. Consistent with the microscopy data, Western Blot analysis of proteins obtained from freshly isolated mTAL treated with 100 µM H2O2 exhibited increased activity/phosphorylation of AKT (pAKTSer473/AKT) that was inhibited by PP242. This was associated with increased protein activity of the apical membrane cotransporter Na+-K+-2Cl- (NKCC2) and the Na/H exchanger (NHE-3). Na+-K+-ATPase activity was increased as reflected an increase in the ratio of pNa+-K+-ATPaseSer16 to total Na+-K+-ATPase. Overall, the results indicate that H2O2 mediated activation of mTORC2 plays a key role in transducing the observed increases of cytosolic [Na+]i despite associated increases of basolateral pump activity.
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Affiliation(s)
- Nadezhda N Zheleznova
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI, 53226, USA.
| | - Vikash Kumar
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI, 53226, USA
| | - Theresa Kurth
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI, 53226, USA
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI, 53226, USA.
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8
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Chen XJ, Zhang H, Yang F, Liu Y, Chen G. DNA Methylation Sustains "Inflamed" Memory of Peripheral Immune Cells Aggravating Kidney Inflammatory Response in Chronic Kidney Disease. Front Physiol 2021; 12:637480. [PMID: 33737884 PMCID: PMC7962671 DOI: 10.3389/fphys.2021.637480] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 02/04/2021] [Indexed: 01/19/2023] Open
Abstract
The incidence of chronic kidney disease (CKD) has rapidly increased in the past decades. A progressive loss of kidney function characterizes a part of CKD even with intensive supportive treatment. Irrespective of its etiology, CKD progression is generally accompanied with the development of chronic kidney inflammation that is pathologically featured by the low-grade but chronic activation of recruited immune cells. Cumulative evidence support that aberrant DNA methylation pattern of diverse peripheral immune cells, including T cells and monocytes, is closely associated with CKD development in many chronic disease settings. The change of DNA methylation profile can sustain for a long time and affect the future genes expression in the circulating immune cells even after they migrate from the circulation into the involved kidney. It is of clinical interest to reveal the underlying mechanism of how altered DNA methylation regulates the intensity and the time length of the inflammatory response in the recruited effector cells. We and others recently demonstrated that altered DNA methylation occurs in peripheral immune cells and profoundly contributes to CKD development in systemic chronic diseases, such as diabetes and hypertension. This review will summarize the current findings about the influence of aberrant DNA methylation on circulating immune cells and how it potentially determines the outcome of CKD.
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Affiliation(s)
- Xiao-Jun Chen
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, China.,Hunan Key Laboratory of Kidney Disease and Blood Purification, Changsha, China
| | - Hong Zhang
- Department of Cardiovascular Surgery, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Fei Yang
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, China.,Hunan Key Laboratory of Kidney Disease and Blood Purification, Changsha, China
| | - Yu Liu
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, China.,Hunan Key Laboratory of Kidney Disease and Blood Purification, Changsha, China
| | - Guochun Chen
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, China.,Hunan Key Laboratory of Kidney Disease and Blood Purification, Changsha, China
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9
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Zhang C, Fang X, Zhang H, Gao W, Hsu HJ, Roman RJ, Fan F. Genetic susceptibility of hypertension-induced kidney disease. Physiol Rep 2021; 9:e14688. [PMID: 33377622 PMCID: PMC7772938 DOI: 10.14814/phy2.14688] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 11/22/2020] [Accepted: 11/27/2020] [Indexed: 02/06/2023] Open
Abstract
Hypertension is the second leading cause of end-stage renal disease (ESRD) after diabetes mellitus. The significant differences in the incidence of hypertensive ESRD between different patient populations worldwide and patients with and without family history indicate that genetic determinants play an important role in the onset and progression of this disease. Recent studies have identified genetic variants and pathways that may contribute to the alteration of renal function. Mechanisms involved include affecting renal hemodynamics (the myogenic and tubuloglomerular feedback responses); increasing the production of reactive oxygen species in the tubules; altering immune cell function; changing the number, structure, and function of podocytes that directly cause glomerular damage. Studies with hypertensive animal models using substitution mapping and gene knockout strategies have identified multiple candidate genes associated with the development of hypertension and subsequent renal injury. Genome-wide association studies have implicated genetic variants in UMOD, MYH9, APOL-1, SHROOM3, RAB38, and DAB2 have a higher risk for ESRD in hypertensive patients. These findings provide genetic evidence of potential novel targets for drug development and gene therapy to design individualized treatment of hypertension and related renal injury.
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Affiliation(s)
- Chao Zhang
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterJacksonMississippiUSA
- Department of UrologyZhongshan HospitalFudan UniversityShanghaiChina
| | - Xing Fang
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterJacksonMississippiUSA
| | - Huawei Zhang
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterJacksonMississippiUSA
| | - Wenjun Gao
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterJacksonMississippiUSA
- Department of UrologyZhongshan HospitalFudan UniversityShanghaiChina
| | - Han Jen Hsu
- Department of UrologyZhongshan HospitalFudan UniversityShanghaiChina
| | - Richard J. Roman
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterJacksonMississippiUSA
| | - Fan Fan
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterJacksonMississippiUSA
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10
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Sadri S, Tomar N, Yang C, Audi SH, Cowley AW, Dash RK. Mechanistic computational modeling of the kinetics and regulation of NADPH oxidase 2 assembly and activation facilitating superoxide production. Free Radic Res 2020; 54:695-721. [PMID: 33059489 DOI: 10.1080/10715762.2020.1836368] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Reactive oxygen species (ROS) play a crucial role in many physiological processes. However, ROS overproduction leads to oxidative stress, which plays a critical role in cell injury/death and the pathogenesis of many diseases. Members of NADPH oxidase (NOX) family, most of which are comprised of membrane and cytosolic components, are known to be the major nonmitochondrial sources of ROS in many cells. NOX2 is a widely-expressed and well-studied NOX family member, which is activated upon assembly of its membrane subunits gp91 phox and p22 phox with its cytosolic subunits p40 phox , p47 phox , p67 phox , and Rac, facilitating ROS production. NOX2 activation is also enhanced by GTP and inhibited by GDP. However, there remains a lack of a mechanistic, quantitative, and integrated understanding of the kinetics and regulation of the assembly of these subunits and their relative contributions toward NOX2 activation and ROS production. Toward this end, we have developed a mechanistic computational model, which incorporates a generalized random rapid equilibrium binding mechanism for NOX2 assembly and activation as well as regulations by GTP (activation), GDP (inhibition), and individual subunits enhancing the binding of other subunits (mutual binding enhancement). The resulting model replicates diverse published kinetic data, including subunit concentration-dependent NOX2 activation and ROS production, under different assay conditions, with appropriate estimates of the unknown model parameters. The model provides a mechanistic, quantitative, and integrated framework for investigating the critical roles of NOX2 subunits in NOX2 assembly and activation facilitating ROS production in a variety of physiological and pathophysiological conditions. However, there is also a need for better quantitative kinetic data based on current understanding of NOX2 assembly and activation in order to test and further develop this model.
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Affiliation(s)
- Shima Sadri
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WIS, USA
| | - Namrata Tomar
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WIS, USA
| | - Chun Yang
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WIS, USA
| | - Said H Audi
- Department of Biomedical Engineering, Marquette University, Milwaukee, WIS, USA
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WIS, USA
| | - Ranjan K Dash
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WIS, USA.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WIS, USA
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11
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Mehrvar S, Foomani FH, Shimada S, Yang C, Zheleznova NN, Mostaghimi S, Cowley AW, Ranji M. The early effects of uninephrectomy on rat kidney metabolic state using optical imaging. JOURNAL OF BIOPHOTONICS 2020; 13:e202000089. [PMID: 32436651 DOI: 10.1002/jbio.202000089] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 05/13/2020] [Accepted: 05/14/2020] [Indexed: 05/09/2023]
Abstract
Uninephrectomy (UNX) is known to result in structural and metabolic changes to the remaining kidney, although it is uncertain if this alters the mitochondrial redox state and how soon such changes may occur. A custom-designed fluorescence cryo-imaging technique was used to quantitatively assess the effect of UNX by measuring the levels of nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) in the remaining kidney. Kidneys were snap-frozen 3 days following UNX, and the intrinsic fluorescence of NADH and FAD were optically acquired. The 3D images were created to characterize the NADH/FAD redox ratios (RR) of the right kidneys, which underwent UNX and the remaining kidneys 3 days following UNX. Both the NADPH-oxidases (Nox2 and Nox4) and the mitochondria are the main sources of reactive oxygen species (ROS) production in tubular epithelial cells. Responses to the UNX were obtained in kidneys of normal Sprague Dawley (SD) rats, Dahl salt-sensitive (SS) rats and SS rats in which NADPH-oxidase isoform 4 (Nox4) was knocked out (SSNox4-/- ). The results found that each of the strains exhibited similar increase in kidney weights averaging 17% after 3 days of UNX. SD and SSNox4-/- rats both exhibited global reductions of the RR (P < .05) with a similar tendency observed in SS rats (P < .08), indicating increased ROS production. The unexpected reduction of the RR in the remnant kidneys of SSNox4-/- rats indicates that mechanisms independent of H2 O2 produced from Nox4 may be responsible for this global increase of ROS. We propose that the reduced RR was largely a consequence of enhanced mitochondrial bioenergetics due to increased tubular workload of the remaining kidney. The data indicate that mitochondria become the dominant source of increased ROS following UNX and could represent an important hypertrophic signaling mechanism.
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Affiliation(s)
- Shima Mehrvar
- Biophotonics Lab, Department of Electrical Engineering, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Farnaz H Foomani
- Biophotonics Lab, Department of Electrical Engineering, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Satoshi Shimada
- Department of Physiology, Medical College of Wisconsin, Wauwatosa, Wisconsin, USA
| | - Chun Yang
- Department of Physiology, Medical College of Wisconsin, Wauwatosa, Wisconsin, USA
| | | | - Soudeh Mostaghimi
- Biophotonics Lab, Department of Electrical Engineering, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Wauwatosa, Wisconsin, USA
| | - Mahsa Ranji
- Biophotonics Lab, Department of Electrical Engineering, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
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12
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Pavlov TS, Palygin O, Isaeva E, Levchenko V, Khedr S, Blass G, Ilatovskaya DV, Cowley AW, Staruschenko A. NOX4-dependent regulation of ENaC in hypertension and diabetic kidney disease. FASEB J 2020; 34:13396-13408. [PMID: 32799394 DOI: 10.1096/fj.202000966rr] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/17/2020] [Accepted: 07/20/2020] [Indexed: 12/11/2022]
Abstract
NADPH oxidase 4 (NOX4) is the most abundant NOX isoform in the kidney; however, its importance for renal function has only recently emerged. The NOX4-dependent pathway regulates many factors essential for proper sodium handling in the distal nephron. However, the functional significance of this pathway in the control of sodium reabsorption during the initiation of chronic kidney disease is not established. The goal of this study was to test Nox4-dependent ENaC regulation in two models: SS hypertension and STZ-induced type 1 diabetes. First, we showed that genetic ablation of Nox4 in Dahl salt-sensitive (SS) rat attenuated a high-salt (HS)-induced increase in epithelial Na+ channel (ENaC) activity in the cortical collecting duct. We also found that H2 O2 upregulated ENaC activity, and H2 O2 production was reduced in both the renal cortex and medulla in SSNox4-/- rats fed an HS diet. Second, in the streptozotocin model of hyperglycemia-induced renal injury ENaC activity in hyperglycemic animals was elevated in SS but not SSNox4-/- rats. NaCl cotransporter (NCC) expression was increased compared to healthy controls, while expression values between SS and SSNox4-/- groups were similar. These data emphasize a critical contribution of the NOX4-mediated pathway in maladaptive upregulation of ENaC-mediated sodium reabsorption in the distal nephron in the conditions of HS- and hyperglycemia-induced kidney injury.
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Affiliation(s)
- Tengis S Pavlov
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Division of Hypertension and Vascular Research, Henry Ford Health System, Detroit, MI, USA
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Elena Isaeva
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - Sherif Khedr
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Physiology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Gregory Blass
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Alexander Staruschenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Clement J. Zablocki VA Medical Center, Milwaukee, WI, USA
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13
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Szpirer C. Rat models of human diseases and related phenotypes: a systematic inventory of the causative genes. J Biomed Sci 2020; 27:84. [PMID: 32741357 PMCID: PMC7395987 DOI: 10.1186/s12929-020-00673-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 07/09/2020] [Indexed: 12/13/2022] Open
Abstract
The laboratory rat has been used for a long time as the model of choice in several biomedical disciplines. Numerous inbred strains have been isolated, displaying a wide range of phenotypes and providing many models of human traits and diseases. Rat genome mapping and genomics was considerably developed in the last decades. The availability of these resources has stimulated numerous studies aimed at discovering causal disease genes by positional identification. Numerous rat genes have now been identified that underlie monogenic or complex diseases and remarkably, these results have been translated to the human in a significant proportion of cases, leading to the identification of novel human disease susceptibility genes, helping in studying the mechanisms underlying the pathological abnormalities and also suggesting new therapeutic approaches. In addition, reverse genetic tools have been developed. Several genome-editing methods were introduced to generate targeted mutations in genes the function of which could be clarified in this manner [generally these are knockout mutations]. Furthermore, even when the human gene causing a disease had been identified without resorting to a rat model, mutated rat strains (in particular KO strains) were created to analyze the gene function and the disease pathogenesis. Today, over 350 rat genes have been identified as underlying diseases or playing a key role in critical biological processes that are altered in diseases, thereby providing a rich resource of disease models. This article is an update of the progress made in this research and provides the reader with an inventory of these disease genes, a significant number of which have similar effects in rat and humans.
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Affiliation(s)
- Claude Szpirer
- Université Libre de Bruxelles, B-6041, Gosselies, Belgium.
- , Waterloo, Belgium.
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14
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Kumar V, Kurth T, Zheleznova NN, Yang C, Cowley AW. NOX4/H 2O 2/mTORC1 Pathway in Salt-Induced Hypertension and Kidney Injury. Hypertension 2020; 76:133-143. [PMID: 32475313 PMCID: PMC10629473 DOI: 10.1161/hypertensionaha.120.15058] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 04/27/2020] [Indexed: 11/16/2022]
Abstract
We have reported that a high-salt (4.0% NaCl) dietary intake activates mTORC1 and inhibition of this pathway with rapamycin blunts the chronic phase of salt-induced hypertension and renal injury in Dahl salt-sensitive (SS) rats. In SS rats, high-salt intake is known to increase the renal production of H2O2 by NOX4, the most abundant NOX isoform in the kidney, and the global knockout of NOX4 blunts salt-sensitivity in these rats. Here, we explored the hypothesis that elevations of H2O2 by NOX4 in high-salt fed SS rat stimulate mTORC1 for the full development of salt-induced hypertension and renal injury. Our in vitro studies found that H2O2 activates mTORC1 independent of PI3K/AKT and AMPK pathways. To determine the in vivo relevance of NOX4/H2O2/mTORC1 in the salt-induced hypertension, SS-Nox4 knockout (SSNox4-/-) rats were daily administrated with vehicle/rapamycin fed a high-salt diet for 21 days. Rapamycin treatment of SSNox4-/- rats had shown no augmented effect on the salt-induced hypertension nor upon indices of renal injury. Significant reductions of renal T lymphocyte and macrophage together with inhibition of cell proliferation were observed in rapamycin treated rats suggesting a role of mTORC1 independent of NOX4 in the proliferation of immune cell. Given the direct activation of mTORC1 by H2O2 and absence of any further protection from salt-induced hypertension in rapamycin-treated SSNox4-/- rats, we conclude that NOX4-H2O2 is a major upstream activator of mTORC1 that contributes importantly to salt-induced hypertension and renal injury in the SS rat model.
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Affiliation(s)
- Vikash Kumar
- From the Department of Physiology, Medical College of Wisconsin, Milwaukee
| | - Theresa Kurth
- From the Department of Physiology, Medical College of Wisconsin, Milwaukee
| | | | - Chun Yang
- From the Department of Physiology, Medical College of Wisconsin, Milwaukee
| | - Allen W Cowley
- From the Department of Physiology, Medical College of Wisconsin, Milwaukee
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15
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Liu Y, Shen W, Chen Q, Cao Q, Di W, Lan R, Chen Z, Bai J, Han Z, Xu W. Inhibition of RAGE by FPS-ZM1 alleviates renal injury in spontaneously hypertensive rats. Eur J Pharmacol 2020; 882:173228. [PMID: 32502492 DOI: 10.1016/j.ejphar.2020.173228] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/14/2020] [Accepted: 05/28/2020] [Indexed: 12/28/2022]
Abstract
The current study was designed to examine the protection of RAGE-specific inhibitor FPS-ZM1 against renal injury in spontaneously hypertensive rats (SHR) and investigate the underlying mechanism. The adult male SHR were treated with FPS-ZM1 via oral gavages for 12 weeks, and age-matched male Wistar-Kyoto rats (WKY) were used as control. Treatment of SHR with FPS-ZM1 slightly reduced blood pressure, and significantly improved baroreflex sensitivity in SHR. Treatment of SHR with FPS-ZM1 improved renal function, evidenced by increased glomerular filtration rate and renal blood flow, and reduced plasma creatinine, blood urea nitrogen and urine albumin excretion rate. Histology results revealed that treatment of SHR with FPS-ZM1 alleviated renal injury and reduced tubulointerstitial fibrosis. Treatment of SHR with FPS-ZM1 suppressed activation of NF-κB and reduced expression of pro-inflammatory cytokines including Tnf, Il6, and Il1b. Treatment of SHR with FPS-ZM1 abated oxidative stress and downregulated mRNA levels of components of NADPH oxidase (Nox) including Cyba, Nox1, Nox2, Nox4 and Ncf1 in kidneys. In addition, treatment of SHR with FPS-ZM1 reduced renal AngII levels, downregulated mRNA expression of Ace and upregulated expression of Agtr2. In conclusion, treatment with FPS-ZM1 alleviated hypertension-related renal dysfunction, possibly by suppressing NF-κB-mediated inflammation, abating Nox-mediated oxidative stress, and improving local renal renin-angiotensin system (RAS).
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Affiliation(s)
- Yu Liu
- Department of Cardiology, Nanjing University Medical School Affiliated Nanjing, Drum Tower Hospital, Nanjing, China
| | - Wenzhi Shen
- Department of Cardiology, Nanjing University Medical School Affiliated Nanjing, Drum Tower Hospital, Nanjing, China
| | - Qi Chen
- Department of Cardiology, Biomedical Research Center, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Qingxin Cao
- Huadong Medical Institute of Biotechniques, Nanjing, China
| | - Wencheng Di
- Department of Cardiology, Nanjing University Medical School Affiliated Nanjing, Drum Tower Hospital, Nanjing, China
| | - Rongfang Lan
- Department of Cardiology, Nanjing University Medical School Affiliated Nanjing, Drum Tower Hospital, Nanjing, China
| | - Zheng Chen
- Department of Cardiology, Nanjing University Medical School Affiliated Nanjing, Drum Tower Hospital, Nanjing, China
| | - Jian Bai
- Department of Cardiology, Nanjing University Medical School Affiliated Nanjing, Drum Tower Hospital, Nanjing, China
| | - Zhonglin Han
- Department of Cardiology, Nanjing University Medical School Affiliated Nanjing, Drum Tower Hospital, Nanjing, China
| | - Wei Xu
- Department of Cardiology, Nanjing University Medical School Affiliated Nanjing, Drum Tower Hospital, Nanjing, China.
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16
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Verschuren EHJ, Castenmiller C, Peters DJM, Arjona FJ, Bindels RJM, Hoenderop JGJ. Sensing of tubular flow and renal electrolyte transport. Nat Rev Nephrol 2020; 16:337-351. [DOI: 10.1038/s41581-020-0259-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/06/2020] [Indexed: 02/06/2023]
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17
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Domondon M, Polina I, Nikiforova AB, Sultanova RF, Kruger C, Vasileva VY, Fomin MV, Beeson GC, Nieminen AL, Smythe N, Maldonado EN, Stadler K, Ilatovskaya DV. Renal Glomerular Mitochondria Function in Salt-Sensitive Hypertension. Front Physiol 2020; 10:1588. [PMID: 32116733 PMCID: PMC7010849 DOI: 10.3389/fphys.2019.01588] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 12/19/2019] [Indexed: 12/16/2022] Open
Abstract
Salt-sensitive (SS) hypertension is accompanied with an early onset of proteinuria, which results from the loss of glomerular podocytes. Here, we hypothesized that glomerular damage in the SS hypertension occurs in part due to mitochondria dysfunction, and we used a unique model of freshly isolated glomeruli to test this hypothesis. In order to mimic SS hypertension, we used Dahl SS rats, an established animal model. Animals were fed a 0.4% NaCl (normal salt, NS) diet or challenged with a high salt (HS) 4% NaCl diet for 21 days to induce an increase in blood pressure (BP). Similar to previous studies, we found that HS diet caused renal hypertrophy, increased BP, glomerulosclerosis, and renal lesions such as fibrosis and protein casts. We did not observe changes in mitochondrial biogenesis in the renal cortex or isolated glomeruli fractions. However, Seahorse assay performed on freshly isolated glomeruli revealed that basal mitochondrial respiration, maximal respiration, and spare respiratory capacity were lower in the HS compared to the NS group. Using confocal imaging and staining for mitochondrial H2O2 using mitoPY1, we detected an intensified response to an acute H2O2 application in the podocytes of the glomeruli isolated from the HS diet fed group. TEM analysis showed that glomerular mitochondria from the HS diet fed group have structural abnormalities (swelling, enlargement, less defined cristae). Therefore, we report that glomerular mitochondria in SS hypertension are functionally and structurally defective, and this impairment could eventually lead to loss of podocytes and proteinuria. Thus, the glomerular–mitochondria axis can be targeted in novel treatment strategies for hypertensive glomerulosclerosis.
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Affiliation(s)
- Mark Domondon
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, United States
| | - Iuliia Polina
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, United States
| | - Anna B Nikiforova
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, United States.,Institute of Theoretical and Experimental Biophysics, Pushchino, Russia
| | - Regina F Sultanova
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, United States.,Saint-Petersburg State Chemical Pharmaceutical University, Saint Petersburg, Russia
| | - Claudia Kruger
- Oxidative Stress and Disease Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, United States
| | - Valeriia Y Vasileva
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, United States.,Institute of Cytology Russian Academy of Science, Saint Petersburg, Russia
| | - Mikhail V Fomin
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, United States
| | - Gyda C Beeson
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, SC, United States
| | - Anna-Liisa Nieminen
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, SC, United States
| | - Nancy Smythe
- Department of Pathology, Medical University of South Carolina, Charleston, SC, United States
| | - Eduardo N Maldonado
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, SC, United States
| | - Krisztian Stadler
- Oxidative Stress and Disease Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, United States
| | - Daria V Ilatovskaya
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, United States
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18
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Saez F, Hong NJ, Cabral PD, Garvin JL. Stretch-Induced Increases in Intracellular Ca Stimulate Thick Ascending Limb O 2- Production and Are Enhanced in Dahl Salt-Sensitive Rats. Hypertension 2019; 75:431-438. [PMID: 31865796 DOI: 10.1161/hypertensionaha.119.13765] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mechanical stretch raises intracellular Ca (Cai) in many cell types. Luminal flow-derived stretch stimulates O2- production by thick ascending limbs (THALs). Renal O2- is greater in Dahl salt-sensitive (SS) than salt-resistant (SR) rats. We hypothesized that mechanical stretch stimulates Ca influx via TRPV4 (transient receptor potential vanilloid type 4) which in turn raises Cai in THALs; these increases in Cai are necessary for stretch to augment O2- production; and stretch-stimulated, and therefore flow-induced, O2- production is enhanced in SS compared with SR THALs due to elevated Ca influx and increased Cai. Cai and O2- were measured in SS and SR THALs from rats on normal salt using Fura2-acetoxymethyl ester and dihydroethidium, respectively. Stretch raised Cai in SS by 270.4±48.9 nmol/L and by 123.6±27.0 nmol/L in SR THALs (P<0.02). Removing extracellular Ca eliminated the increases and differences in Cai between strains. Knocking down TRPV4 in SS THALs reduced stretch-induced Cai to SR levels (SS: 92.0±15.9 nmol/L; SR: 123.6±27.0 nmol/L). RN1734, a TRPV4 inhibitor, blunted stretch-elevated Cai by ≈75% and ≈66% in SS (P<0.03) and SR (P<0.04), respectively. Stretch augmented O2- production by 58.6±10.2 arbitrary fluorescent units/min in SS and by 24.4±2.6 arbitrary fluorescent units/min in SR THALs (P<0.05). Removal of extracellular Ca blunted stretch-induced increases in O2- and eliminated differences between strains. RN1734 reduced stretch-induced O2- by ≈70% in SS (P<0.005) and ≈60% in SR (P<0.01). Conclusions are as follows: (1) stretch activates TRPV4, which raises Cai in THALs; (2) the increase in Cai stimulates O2- production; and (3) stretch-induced O2- production is enhanced in SS THALs due to greater increases in Cai.
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Affiliation(s)
- Fara Saez
- From the Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH
| | - Nancy J Hong
- From the Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH
| | - Pablo D Cabral
- From the Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH
| | - Jeffrey L Garvin
- From the Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH
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19
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Dasinger JH, Alsheikh AJ, Abais-Battad JM, Pan X, Fehrenbach DJ, Lund H, Roberts ML, Cowley AW, Kidambi S, Kotchen TA, Liu P, Liang M, Mattson DL. Epigenetic Modifications in T Cells: The Role of DNA Methylation in Salt-Sensitive Hypertension. Hypertension 2019; 75:372-382. [PMID: 31838911 DOI: 10.1161/hypertensionaha.119.13716] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The SS (Dahl salt sensitive) rat is an established model of hypertension and renal damage that is accompanied with immune system activation in response to a high-salt diet. Investigations into the effects of sodium-independent and dependent components of the diet were shown to affect the disease phenotype with SS/MCW (JrHsdMcwi) rats maintained on a purified diet (AIN-76A) presenting with a more severe phenotype relative to grain-fed SS/CRL (JrHsdMcwiCrl) rats. Since contributions of the immune system, environment, and diet are documented to alter this phenotype, this present study examined the epigenetic profile of T cells isolated from the periphery and the kidney from these colonies. T cells isolated from kidneys of the 2 colonies revealed that transcriptomic and functional differences may contribute to the susceptibility of hypertension and renal damage. In response to high-salt challenge, the methylome of T cells isolated from the kidney of SS/MCW exhibit a significant increase in differentially methylated regions with a preference for hypermethylation compared with the SS/CRL kidney T cells. Circulating T cells exhibited similar methylation profiles between colonies. Utilizing transcriptomic data from T cells isolated from the same animals upon which the DNA methylation analysis was performed, a predominant negative correlation was observed between gene expression and DNA methylation in all groups. Lastly, inhibition of DNA methyltransferases blunted salt-induced hypertension and renal damage in the SS/MCW rats providing a functional role for methylation. This study demonstrated the influence of epigenetic modifications to immune cell function, highlighting the need for further investigations.
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Affiliation(s)
- John Henry Dasinger
- From the Departments of Physiology (J.H.D., A.J.A., J.M.A.-B., X.P., D.J.F., H.L., M.L.R., A.W.C., P.L., M.L., D.L.M.), Medical College of Wisconsin Milwaukee, Wisconsin, USA
| | - Ammar J Alsheikh
- From the Departments of Physiology (J.H.D., A.J.A., J.M.A.-B., X.P., D.J.F., H.L., M.L.R., A.W.C., P.L., M.L., D.L.M.), Medical College of Wisconsin Milwaukee, Wisconsin, USA
| | - Justine M Abais-Battad
- From the Departments of Physiology (J.H.D., A.J.A., J.M.A.-B., X.P., D.J.F., H.L., M.L.R., A.W.C., P.L., M.L., D.L.M.), Medical College of Wisconsin Milwaukee, Wisconsin, USA
| | - Xiaoqing Pan
- From the Departments of Physiology (J.H.D., A.J.A., J.M.A.-B., X.P., D.J.F., H.L., M.L.R., A.W.C., P.L., M.L., D.L.M.), Medical College of Wisconsin Milwaukee, Wisconsin, USA
| | - Daniel J Fehrenbach
- From the Departments of Physiology (J.H.D., A.J.A., J.M.A.-B., X.P., D.J.F., H.L., M.L.R., A.W.C., P.L., M.L., D.L.M.), Medical College of Wisconsin Milwaukee, Wisconsin, USA
| | - Hayley Lund
- From the Departments of Physiology (J.H.D., A.J.A., J.M.A.-B., X.P., D.J.F., H.L., M.L.R., A.W.C., P.L., M.L., D.L.M.), Medical College of Wisconsin Milwaukee, Wisconsin, USA
| | - Michelle L Roberts
- From the Departments of Physiology (J.H.D., A.J.A., J.M.A.-B., X.P., D.J.F., H.L., M.L.R., A.W.C., P.L., M.L., D.L.M.), Medical College of Wisconsin Milwaukee, Wisconsin, USA
| | - Allen W Cowley
- From the Departments of Physiology (J.H.D., A.J.A., J.M.A.-B., X.P., D.J.F., H.L., M.L.R., A.W.C., P.L., M.L., D.L.M.), Medical College of Wisconsin Milwaukee, Wisconsin, USA
| | - Srividya Kidambi
- Medicine (S.K., T.A.K.), Medical College of Wisconsin Milwaukee, Wisconsin, USA
| | - Theodore A Kotchen
- Medicine (S.K., T.A.K.), Medical College of Wisconsin Milwaukee, Wisconsin, USA
| | - Pengyuan Liu
- From the Departments of Physiology (J.H.D., A.J.A., J.M.A.-B., X.P., D.J.F., H.L., M.L.R., A.W.C., P.L., M.L., D.L.M.), Medical College of Wisconsin Milwaukee, Wisconsin, USA
| | - Mingyu Liang
- From the Departments of Physiology (J.H.D., A.J.A., J.M.A.-B., X.P., D.J.F., H.L., M.L.R., A.W.C., P.L., M.L., D.L.M.), Medical College of Wisconsin Milwaukee, Wisconsin, USA
| | - David L Mattson
- From the Departments of Physiology (J.H.D., A.J.A., J.M.A.-B., X.P., D.J.F., H.L., M.L.R., A.W.C., P.L., M.L., D.L.M.), Medical College of Wisconsin Milwaukee, Wisconsin, USA
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20
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Gonzalez-Vicente A, Hong N, Garvin JL. Effects of reactive oxygen species on renal tubular transport. Am J Physiol Renal Physiol 2019; 317:F444-F455. [PMID: 31215804 DOI: 10.1152/ajprenal.00604.2018] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Reactive oxygen species (ROS) play a critical role in regulating nephron transport both via transcellular and paracellular pathways under physiological and pathological circumstances. Here, we review the progress made in the past ~10 yr in understanding how ROS regulate solute and water transport in individual nephron segments. Our knowledge in this field is still rudimentary, with basic information lacking. This is most obvious when looking at the reported disparate effects of superoxide ([Formula: see text]) and H2O2 on proximal nephron transport, where there are no easy explanations as to how to reconcile the data. Similarly, we know almost nothing about the regulation of transport in thin descending and ascending limbs, information that is likely critical to understanding the urine concentrating mechanism. In the thick ascending limb, there is general agreement that ROS enhance transcellular reabsorption of NaCl, but we know very little about their effects on the paracellular pathway and therefore Ca2+ and Mg2+ transport. In the distal convoluted tubule, precious little is known. In the collecting duct, there is general agreement that ROS stimulate the epithelial Na+ channel.
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Affiliation(s)
- Agustin Gonzalez-Vicente
- Department of Inflammation and Immunity, Cleveland Clinic, Lerner Research Institute, Cleveland, Ohio
| | - Nancy Hong
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University Cleveland, Ohio
| | - Jeffrey L Garvin
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University Cleveland, Ohio
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21
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Patel B, Zheleznova NN, Ray SC, Sun J, Cowley AW, O'Connor PM. Voltage gated proton channels modulate mitochondrial reactive oxygen species production by complex I in renal medullary thick ascending limb. Redox Biol 2019; 27:101191. [PMID: 31060879 PMCID: PMC6859587 DOI: 10.1016/j.redox.2019.101191] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 04/02/2019] [Accepted: 04/05/2019] [Indexed: 11/24/2022] Open
Abstract
Hv1 is a voltage-gated proton channel highly expressed in immune cells where, it acts to maintain NAD(P)H oxidase activity during the respiratory burst. We have recently reported that Hv1 is expressed in cells of the medullary thick ascending limb (mTAL) of the kidney and is critical to augment reactive oxygen species (ROS) production by this segment. While Hv1 is associated with NOX2 mediated ROS production in immune cells, the source of the Hv1 dependent ROS in mTAL remains unknown. In the current study, the rate of ROS formation was quantified in freshly isolated mTAL using dihydroethidium and ethidium fluorescence. Hv1 dependent ROS production was stimulated by increasing bath osmolality and ammonium chloride (NH4Cl) loading. Loss of either p67phox or NOX4 did not abolish the formation of ROS in mTAL. Hv1 was localized to mitochondria within mTAL, and the mitochondrial superoxide scavenger mitoTEMPOL reduced ROS formation. Rotenone significantly increased ROS formation and decreased mitochondrial membrane potential in mTAL from wild-type rats, while treatment with this inhibitor decreased ROS formation and increased mitochondrial membrane potential in mTAL from Hv1−/− mutant rats. These data indicate that NADPH oxidase is not the primary source of Hv1 dependent ROS production in mTAL. Rather Hv1 localizes to the mitochondria in mTAL and modulates the formation of ROS by complex I. These data provide a potential explanation for the effects of Hv1 on ROS production in cells independent of its contribution to maintenance of cell membrane potential and intracellular pH.
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Affiliation(s)
- Bansari Patel
- Department of Physiology, Medical College of Georgia, Augusta, Georgia, USA
| | | | - Sarah C Ray
- Department of Physiology, Medical College of Georgia, Augusta, Georgia, USA
| | - Jingping Sun
- Department of Physiology, Medical College of Georgia, Augusta, Georgia, USA
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Paul M O'Connor
- Department of Physiology, Medical College of Georgia, Augusta, Georgia, USA.
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22
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Gonzalez-Vicente A, Saez F, Monzon CM, Asirwatham J, Garvin JL. Thick Ascending Limb Sodium Transport in the Pathogenesis of Hypertension. Physiol Rev 2019; 99:235-309. [PMID: 30354966 DOI: 10.1152/physrev.00055.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The thick ascending limb plays a key role in maintaining water and electrolyte balance. The importance of this segment in regulating blood pressure is evidenced by the effect of loop diuretics or local genetic defects on this parameter. Hormones and factors produced by thick ascending limbs have both autocrine and paracrine effects, which can extend prohypertensive signaling to other structures of the nephron. In this review, we discuss the role of the thick ascending limb in the development of hypertension, not as a sole participant, but one that works within the rich biological context of the renal medulla. We first provide an overview of the basic physiology of the segment and the anatomical considerations necessary to understand its relationship with other renal structures. We explore the physiopathological changes in thick ascending limbs occurring in both genetic and induced animal models of hypertension. We then discuss the racial differences and genetic defects that affect blood pressure in humans through changes in thick ascending limb transport rates. Throughout the text, we scrutinize methodologies and discuss the limitations of research techniques that, when overlooked, can lead investigators to make erroneous conclusions. Thus, in addition to advancing an understanding of the basic mechanisms of physiology, the ultimate goal of this work is to understand our research tools, to make better use of them, and to contextualize research data. Future advances in renal hypertension research will require not only collection of new experimental data, but also integration of our current knowledge.
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Affiliation(s)
| | - Fara Saez
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Casandra M Monzon
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Jessica Asirwatham
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Jeffrey L Garvin
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
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23
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Butcher JT, Mintz JD, Larion S, Qiu S, Ruan L, Fulton DJ, Stepp DW. Increased Muscle Mass Protects Against Hypertension and Renal Injury in Obesity. J Am Heart Assoc 2018; 7:e009358. [PMID: 30369309 PMCID: PMC6201396 DOI: 10.1161/jaha.118.009358] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Accepted: 06/20/2018] [Indexed: 01/06/2023]
Abstract
Background Obesity compromises cardiometabolic function and is associated with hypertension and chronic kidney disease. Exercise ameliorates these conditions, even without weight loss. Although the mechanisms of exercise's benefits remain unclear, augmented lean body mass is a suspected mechanism. Myostatin is a potent negative regulator of skeletal muscle mass that is upregulated in obesity and downregulated with exercise. The current study tested the hypothesis that deletion of myostatin would increase muscle mass and reduce blood pressure and kidney injury in obesity. Methods and Results Myostatin knockout mice were crossed to db/db mice, and metabolic and cardiovascular functions were examined. Deletion of myostatin increased skeletal muscle mass by ≈50% to 60% without concomitant weight loss or reduction in fat mass. Increased blood pressure in obesity was prevented by the deletion of myostatin, but did not confer additional benefit against salt loading. Kidney injury was evident because of increased albuminuria, which was abolished in obese mice lacking myostatin. Glycosuria, total urine volume, and whole kidney NOX-4 levels were increased in obesity and prevented by myostatin deletion, arguing that increased muscle mass provides a multipronged defense against renal dysfunction in obese mice. Conclusions These experimental observations suggest that loss of muscle mass is a novel risk factor in obesity-derived cardiovascular dysfunction. Interventions that increase muscle mass, either through exercise or pharmacologically, may help limit cardiovascular disease in obese individuals.
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Affiliation(s)
- Joshua T. Butcher
- Vascular Biology CenterMedical College of Georgia at Augusta UniversityAugustaGA
| | - James D. Mintz
- Vascular Biology CenterMedical College of Georgia at Augusta UniversityAugustaGA
| | - Sebastian Larion
- Vascular Biology CenterMedical College of Georgia at Augusta UniversityAugustaGA
| | - Shuiqing Qiu
- Vascular Biology CenterMedical College of Georgia at Augusta UniversityAugustaGA
| | - Ling Ruan
- Vascular Biology CenterMedical College of Georgia at Augusta UniversityAugustaGA
| | - David J. Fulton
- Vascular Biology CenterMedical College of Georgia at Augusta UniversityAugustaGA
- Department of PharmacologyMedical College of Georgia at Augusta UniversityAugustaGA
| | - David W. Stepp
- Vascular Biology CenterMedical College of Georgia at Augusta UniversityAugustaGA
- Department of PhysiologyMedical College of Georgia at Augusta UniversityAugustaGA
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24
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Saez F, Hong NJ, Garvin JL. NADPH oxidase 4-derived superoxide mediates flow-stimulated NKCC2 activity in thick ascending limbs. Am J Physiol Renal Physiol 2018; 314:F934-F941. [PMID: 29672130 DOI: 10.1152/ajprenal.00631.2017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Luminal flow augments Na+ reabsorption in the thick ascending limb more than can be explained by increased ion delivery. This segment reabsorbs 30% of the filtered load of Na+, playing a key role in its homeostasis. Whether flow elevations enhance Na+-K+-2Cl- cotransporter (NKCC2) activity and the second messenger involved are unknown. We hypothesized that raising luminal flow augments NKCC2 activity by enhancing superoxide ([Formula: see text]) production by NADPH oxidase 4 (NOX4). NKCC2 activity was measured in thick ascending limbs perfused at either 5 or 20 nl/min with and without inhibitors of [Formula: see text] production. Raising luminal flow from 5 to 20 nl/min enhanced NKCC2 activity from 4.8 ± 0.9 to 6.3 ± 1.2 arbitrary fluorescent units (AFU)/s. Maintaining flow at 5 nl/min did not alter NKCC2 activity. The superoxide dismutase mimetic manganese (III) tetrakis (4-benzoic acid) porphyrin chloride blunted NKCC2 activity from 3.5 ± 0.4 to 2.5 ± 0.2 AFU/s when flow was 20 nl/min but not 5 nl/min. When flow was 20 nl/min, NKCC2 activity showed no change with time. The selective NOX1/4 inhibitor GKT-137831 blunted NKCC2 activity when thick ascending limbs were perfused at 20 nl/min from 7.2 ± 1.1 to 4.5 ± 0.8 AFU/s but not at 5 nl/min. The inhibitor also prevented luminal flow from elevating [Formula: see text] production. Allopurinol, a xanthine oxidase inhibitor, had no effect on NKCC2 activity when flow was 20 nl/min. Tetanus toxin prevents flow-induced stimulation of NKCC2 activity. We conclude that elevations in luminal flow enhance NaCl reabsorption in thick ascending limbs by stimulating NKCC2 via NOX4 activation and increased [Formula: see text]. NKCC2 activation is primarily the result of insertion of new transporters in the membrane.
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Affiliation(s)
- Fara Saez
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Nancy J Hong
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Jeffrey L Garvin
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
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25
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Pahlitzsch T, Liu ZZ, Al-Masri A, Braun D, Dietze S, Persson PB, Schunck WH, Blum M, Kupsch E, Ludwig M, Patzak A. Hypoxia-reoxygenation enhances murine afferent arteriolar vasoconstriction by angiotensin II. Am J Physiol Renal Physiol 2017; 314:F430-F438. [PMID: 29070570 DOI: 10.1152/ajprenal.00252.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We tested the hypothesis that hypoxia-reoxygenation (H/R) augments vasoreactivity to angiotensin II (ANG II). In particular, we compared an in situ live kidney slice model with isolated afferent arterioles (C57Bl6 mice) to assess the impact of tubules on microvessel response. Hematoxylin and eosin staining was used to estimate slice viability. Arterioles in the slices were located by differential interference contrast microscopy, and responses to vasoactive substances were assessed. Cytosolic calcium transients and NADPH oxidase (NOX) mRNA expression were studied in isolated afferent arterioles. SOD activity was measured in live slices. Both experimental models were subjected to control and H/R treatment (60 min). Slices were further analyzed after 30-, 60-, and 90-min hypoxia followed by 10- or 20-min reoxygenation (H/R). H/R resulted in enhanced necrotic tissue damage compared with control conditions. To characterize the slice model, we applied ANG II (10-7 M), norepinephrine (NE; 10-5 M), endothelin-1 (ET-1; 10-7 M), and ATP (10-4 M), reducing the initial diameter to 44.5 ± 2.8, 50.0 ± 2.2, 45.3 ± 2.6, and 74.1 ± 1.8%, respectively. H/R significantly increased the ANG II response compared with control in live slices and in isolated afferent arterioles, although calcium transients remained similar. TEMPOL incubation prevented the H/R effect on ANG II responses. H/R significantly increased NOX2 mRNA expression in isolated arterioles. SOD activity was significantly decreased after H/R. Enhanced arteriolar responses after H/R occurred independently from the surrounding tissue, indicating no influence of tubules on vascular function in this model. The mechanism of increased ANG II response after H/R might be increased oxidative stress and increased calcium sensitivity of the contractile apparatus.
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Affiliation(s)
- Tamara Pahlitzsch
- Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Berlin , Germany
| | - Zhi Zhao Liu
- Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Berlin , Germany
| | - Amira Al-Masri
- Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Berlin , Germany
| | - Diana Braun
- Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Berlin , Germany
| | - Stefanie Dietze
- Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Berlin , Germany
| | - Pontus B Persson
- Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Berlin , Germany
| | | | - Maximilian Blum
- Max-Delbrück Center for Molecular Medicine , Berlin , Germany
| | - Eckehardt Kupsch
- PHZ Institut für Pathologie, Hannover Zentrum, Hannover , Germany
| | - Marion Ludwig
- Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Berlin , Germany
| | - Andreas Patzak
- Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Berlin , Germany
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26
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The Cardiovascular Effect of Systemic Homocysteine Is Associated with Oxidative Stress in the Rostral Ventrolateral Medulla. Neural Plast 2017; 2017:3256325. [PMID: 29098089 PMCID: PMC5643037 DOI: 10.1155/2017/3256325] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 08/15/2017] [Indexed: 12/31/2022] Open
Abstract
It has been demonstrated that homocysteine (HCY) is a significant risk factor of hypertension, which is characterized by overactivity of sympathetic tone. Excessive oxidative stress in the rostral ventrolateral medulla (RVLM), a key region for control of sympathetic outflow, contributes to sympathetic hyperactivity in hypertension. Therefore, the goal of the present study is to determine the effect of systemic HCY on production of reactive oxygen species (ROS) in the RVLM. In the rat model of the diet-induced hyperhomocysteinemia (L-methionine, 1 g/kg/day, 8 weeks), we found that the HCY resulted in a significant increase (≈3.7-fold, P < 0.05) in ROS production in the RVLM, which was paralleled with enhanced sympathetic tone and blood pressure (BP). Compared to the vehicle group, levels of BP and basal renal sympathetic nerve activity in the HCY group were significantly (P < 0.05, n = 5) increased by an average of 27 mmHg and 31%, respectively. Furthermore, the rats treated with L-methionine (1 g/kg/day, 8 weeks) showed an upregulation of NADPHase (NOX4) protein expression and a downregulation of superoxide dismutase protein expression in the RVLM. The current data suggest that central oxidative stress induced by systemic HCY plays an important role in hypertension-associated sympathetic overactivity.
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27
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Blajszczak C, Bonini MG. Mitochondria targeting by environmental stressors: Implications for redox cellular signaling. Toxicology 2017; 391:84-89. [PMID: 28750850 DOI: 10.1016/j.tox.2017.07.013] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 06/22/2017] [Accepted: 07/21/2017] [Indexed: 01/07/2023]
Abstract
Mitochondria are cellular powerhouses as well as metabolic and signaling hubs regulating diverse cellular functions, from basic physiology to phenotypic fate determination. It is widely accepted that reactive oxygen species (ROS) generated in mitochondria participate in the regulation of cellular signaling, and that some mitochondria chronically operate at a high ROS baseline. However, it is not completely understood how mitochondria adapt to persistently high ROS states and to environmental stressors that disturb the redox balance. Here we will review some of the current concepts regarding how mitochondria resist oxidative damage, how they are replaced when excessive oxidative damage compromises function, and the effect of environmental toxicants (i.e. heavy metals) on the regulation of mitochondrial ROS (mtROS) production and subsequent impact.
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Affiliation(s)
- Chuck Blajszczak
- Departments of Medicine and Pathology, University of Illinois College of Medicine at Chicago, IL, USA
| | - Marcelo G Bonini
- Departments of Medicine and Pathology, University of Illinois College of Medicine at Chicago, IL, USA.
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28
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Pavlov TS, Staruschenko A. Involvement of ENaC in the development of salt-sensitive hypertension. Am J Physiol Renal Physiol 2016; 313:F135-F140. [PMID: 28003189 DOI: 10.1152/ajprenal.00427.2016] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 12/20/2016] [Accepted: 12/20/2016] [Indexed: 02/07/2023] Open
Abstract
Salt-sensitive hypertension is associated with renal and vascular dysfunctions, which lead to impaired fluid excretion, increased cardiac output, and total peripheral resistance. It is commonly accepted that increased renal sodium handling and plasma volume expansion are necessary factors for the development of salt-induced hypertension. The epithelial sodium channel (ENaC) is a trimeric ion channel expressed in the distal nephron that plays a critical role in the regulation of sodium reabsorption in both normal and pathological conditions. In this mini-review, we summarize recent studies investigating the role of ENaC in the development of salt-sensitive hypertension. On the basis of experimental data obtained from the Dahl salt-sensitive rats, we and others have demonstrated that abnormal ENaC activation in response to a dietary NaCl load contributes to the development of high blood pressure in this model. The role of different humoral factors, such as the components of the renin-angiotensin-aldosterone system, members of the epidermal growth factors family, arginine vasopressin, and oxidative stress mediating the effects of dietary salt on ENaC are discussed in this review to highlight future research directions and to determine potential molecular targets for drug development.
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Affiliation(s)
- Tengis S Pavlov
- Division of Hypertension and Vascular Research, Henry Ford Hospital, Detroit, Michigan; and
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