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Xu C, Chen Y, Ramkumar N, Zou CJ, Sigmund CD, Yang T. Collecting duct renin regulates potassium homeostasis in mice. Acta Physiol (Oxf) 2023; 237:e13899. [PMID: 36264268 PMCID: PMC10754139 DOI: 10.1111/apha.13899] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 10/15/2022] [Accepted: 10/16/2022] [Indexed: 01/03/2023]
Abstract
AIM The kaliuretic action of the renin-angiotensin-aldosterone system (RAAS) is well established as highlighted by hyperkalemia side effect of RAAS inhibitors but such action is usually ascribed to systemic RAAS. The present study addresses the involvement of intrarenal RAAS in K+ homeostasis with emphasis on locally generated renin within the collecting duct (CD). METHODS Wild-type (Floxed) and CD-specific deletion of renin (CD renin KO) mice were treated for 7 days with a high K+ (HK) diet to investigate the role of CD renin in kaliuresis regulation and further define the underlying mechanism with emphasis on analysis of intrarenal aldosterone biosynthesis. RESULTS In floxed mice, renin levels were elevated in the renal medulla and urine following a 1-week HK diet, indicating activation of the intrarenal renin. CD renin KO mice had blunted HK-induced intrarenal renin response and developed impaired kaliuresis and elevated plasma K+ level (4.45 ± 0.14 vs. 3.89 ± 0.04 mM, p < 0.01). In parallel, HK-induced intrarenal aldosterone and CYP11B2 expression along with expression of renal outer medullary K+ channel (ROMK), calcium-activated potassium channel subunit alpha-1 (α-BK), α-Na+ -K+ -ATPase, and epithelial sodium channel (β-ENaC and cleaved-γ-ENaC) expression were all significantly blunted in CD renin KO mice in contrast to the unaltered responses of plasma aldosterone and adrenal CYP11B2. CONCLUSION Taken together, these results support a kaliuretic action of CD renin during HK intake.
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Affiliation(s)
- Chuanming Xu
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, UT 84132
- Veterans Affairs Medical Center, Salt Lake City, Utah, UT 84132
| | - Yanting Chen
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, UT 84132
- Veterans Affairs Medical Center, Salt Lake City, Utah, UT 84132
| | - Nirupama Ramkumar
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, UT 84132
| | - Chang-Jiang Zou
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, UT 84132
- Veterans Affairs Medical Center, Salt Lake City, Utah, UT 84132
| | - Curt D. Sigmund
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226
| | - Tianxin Yang
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, UT 84132
- Veterans Affairs Medical Center, Salt Lake City, Utah, UT 84132
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Nomura H, Kuruppu S, Rajapakse NW. Stimulation of Angiotensin Converting Enzyme 2: A Novel Treatment Strategy for Diabetic Nephropathy. Front Physiol 2022; 12:813012. [PMID: 35087423 PMCID: PMC8787214 DOI: 10.3389/fphys.2021.813012] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 12/20/2021] [Indexed: 12/11/2022] Open
Abstract
Despite current therapies for diabetic nephropathy, many patients continue to progress to end-stage renal disease requiring renal replacement therapy. While the precise mechanisms underlying diabetic nephropathy remain to be determined, it is well established that chronic activation of the renin angiotensin aldosterone system (RAAS) plays a substantial role in the pathogenesis of diabetic nephropathy. Angiotensin converting enzyme 2 (ACE2), the enzyme responsible for activating the reno-protective arm of the RAAS converts angiotensin (Ang) II into Ang 1-7 which exerts reno-protective effects. Chronic RAAS activation leads to kidney inflammation and fibrosis, and ultimately lead to end-stage kidney disease. Currently, angiotensin converting enzyme inhibitors and Ang II receptor blockers are approved for renal fibrosis and inflammation. Targeting the reno-protective arm of the RAAS should therefore, provide further treatment options for kidney fibrosis and inflammation. In this review, we examine how targeting the reno-protective arm of the RAAS can ameliorate kidney inflammation and fibrosis and rescue kidney function in diabetic nephropathy. We argue tissue ACE2 stimulation provides a unique and promising therapeutic approach for diabetic nephropathy.
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Affiliation(s)
- Haru Nomura
- School of Biomedical Sciences, University of Queensland, Brisbane, QLD, Australia
| | - Sanjaya Kuruppu
- Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Niwanthi W Rajapakse
- School of Biomedical Sciences, University of Queensland, Brisbane, QLD, Australia
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Visniauskas B, Arita DY, Rosales CB, Feroz MA, Luffman C, Accavitti MJ, Dawkins G, Hong J, Curnow AC, Thethi TK, Lefante JJ, Jaimes EA, Mauvais-Jarvis F, Fonseca VA, Prieto MC. Sex differences in soluble prorenin receptor in patients with type 2 diabetes. Biol Sex Differ 2021; 12:33. [PMID: 33933156 PMCID: PMC8088668 DOI: 10.1186/s13293-021-00374-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 04/07/2021] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND The soluble prorenin receptor (sPRR), a member of the renin-angiotensin system (RAS), is elevated in plasma of patients with preeclampsia, hypertension, chronic kidney disease (CKD), and type 2 diabetes. Our goal was to examine the relationship between sPRR and RAS activation to define whether sexual dimorphisms in sPRR might explain sex disparities in renal outcomes in patients with type 2 diabetes. METHODS Two hundred sixty-nine participants were included in the study (mean age, 48 ± 16 years; 42% men, 58% women), including 173 controls and 96 subjects with type 2 diabetes. In plasma and urine, we measured sPRR, plasma renin activity (PRA), and prorenin. In the urine, we also measured angiotensinogen along with other biomarkers of renal dysfunction. RESULTS Plasma sPRR and PRA were significantly higher in women with type 2 diabetes compared to men. In these women, plasma sPRR was positively correlated with PRA, age, and body mass index (BMI). In contrast, in men the sPRR in urine but not in plasma positively correlated with eGFR in urine, but negatively correlated with urine renin activity, plasma glucose, age, and BMI. CONCLUSIONS In patients with type 2 diabetes, sPRR contributes to RAS stimulation in a sex-dependent fashion. In diabetic women, increased plasma sPRR parallels the activation of systemic RAS; while in diabetic men, decreased sPRR in urine matches intrarenal RAS stimulation. sPRR might be a potential indicator of intrarenal RAS activation and renal dysfunction in men and women with type 2 diabetes.
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Affiliation(s)
- Bruna Visniauskas
- Department of Physiology, Tulane University School of Medicine, 1430 Tulane Avenue, SL39, New Orleans, LA 70112 USA
| | - Danielle Y. Arita
- Department of Physiology, Tulane University School of Medicine, 1430 Tulane Avenue, SL39, New Orleans, LA 70112 USA
| | - Carla B. Rosales
- Department of Physiology, Tulane University School of Medicine, 1430 Tulane Avenue, SL39, New Orleans, LA 70112 USA
| | - Mohammed A. Feroz
- Department of Physiology, Tulane University School of Medicine, 1430 Tulane Avenue, SL39, New Orleans, LA 70112 USA
| | - Christina Luffman
- Department of Physiology, Tulane University School of Medicine, 1430 Tulane Avenue, SL39, New Orleans, LA 70112 USA
| | - Michael J. Accavitti
- Department of Physiology, Tulane University School of Medicine, 1430 Tulane Avenue, SL39, New Orleans, LA 70112 USA
| | - Gabrielle Dawkins
- Department of Physiology, Tulane University School of Medicine, 1430 Tulane Avenue, SL39, New Orleans, LA 70112 USA
| | - Jennifer Hong
- Department of Physiology, Tulane University School of Medicine, 1430 Tulane Avenue, SL39, New Orleans, LA 70112 USA
| | - Andrew C. Curnow
- Department of Physiology, Tulane University School of Medicine, 1430 Tulane Avenue, SL39, New Orleans, LA 70112 USA
| | - Tina K. Thethi
- Department of Medicine, Endocrinology Division, Tulane University School of Medicine, New Orleans, LA USA
- AdventHealth, Translational Research Institute, Orlando, FL USA
| | - John J. Lefante
- Department of Biostatistics and Data Science, School of Public Health and Tropical Medicine, New Orleans, LA USA
| | - Edgar A. Jaimes
- Renal Service, Memorial Sloan Kettering Cancer Center, New York, NY USA
| | - Franck Mauvais-Jarvis
- Department of Medicine, Endocrinology Division, Tulane University School of Medicine, New Orleans, LA USA
- Southeast Louisiana Veterans Healthcare System, New Orleans, LA USA
- Tulane Center of Excellence in Sex-Based Biology and Medicine, New Orleans, LA USA
| | - Vivian A. Fonseca
- Department of Medicine, Endocrinology Division, Tulane University School of Medicine, New Orleans, LA USA
- Southeast Louisiana Veterans Healthcare System, New Orleans, LA USA
| | - Minolfa C. Prieto
- Department of Physiology, Tulane University School of Medicine, 1430 Tulane Avenue, SL39, New Orleans, LA 70112 USA
- Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, LA USA
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Sun Y, Goes Martini A, Janssen MJ, Garrelds IM, Masereeuw R, Lu X, Danser AHJ. Megalin: A Novel Endocytic Receptor for Prorenin and Renin. Hypertension 2020; 75:1242-1250. [PMID: 32200675 DOI: 10.1161/hypertensionaha.120.14845] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Megalin is an endocytic receptor contributing to protein reabsorption. Impaired expression or trafficking of megalin increases urinary renin and allowed the detection of prorenin, which normally is absent in urine. Here, we investigated (pro)renin uptake by megalin, using both conditionally immortalized proximal tubule epithelial cells and Brown Norway Rat yolk sac cells (BN16). To distinguish binding and internalization, cells were incubated with recombinant human (pro)renin at 4°C and 37°C, respectively. (Pro)renin levels were assessed by immunoradiometric assay. At 4°C, BN16 cells bound 3× more prorenin than renin, suggestive for a higher affinity of prorenin. Similarly, at 37°C, prorenin accumulated at 3- to 4-fold higher levels than renin in BN16 cells. Consequently, depletion of medium prorenin (but not renin) content occurred after 24 hours. No such differences were observed in conditionally immortalized proximal tubule epithelial cells, and M6P (mannose-6-phosphate) greatly reduced conditionally immortalized proximal tubule epithelial cells (pro)renin uptake, suggesting that these cells accumulate (pro)renin largely via M6P receptors. M6P did not affect (pro)renin uptake in BN16 cells. Yet, inhibiting megalin expression with siRNA greatly reduced (pro)renin binding and internalization by BN16 cells. Furthermore, treating BN16 cells with albumin, an endogenous ligand of megalin, also decreased binding and internalization of (pro)renin, while deleting the (pro)renin receptor affected the latter only. Exposing prorenin's prosegment with the renin inhibitor aliskiren dramatically increased prorenin binding, while after prosegment cleavage with trypsin prorenin binding was identical to that of renin. In conclusion, megalin might function as an endocytic receptor for (pro)renin and displays a preference for prorenin. Megalin-mediated endocytosis requires the (pro)renin receptor.
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Affiliation(s)
- Yuan Sun
- From the Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands (Y.S., A.G.M., I.M.G., A.H.J.D.).,Department of Physiology, Shenzhen University Health Science Center, Shenzhen University, China (Y.S., X.L.).,Translational Medicine Collaborative Innovation Center, The Second Clinical Medical College (Shenzhen People's Hospital) of Jinan University, Shenzhen, China (Y.S.)
| | - Alexandre Goes Martini
- From the Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands (Y.S., A.G.M., I.M.G., A.H.J.D.)
| | - Manoe J Janssen
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, the Netherlands (M.J.J., R.M.)
| | - Ingrid M Garrelds
- From the Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands (Y.S., A.G.M., I.M.G., A.H.J.D.)
| | - Rosalinde Masereeuw
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, the Netherlands (M.J.J., R.M.)
| | - Xifeng Lu
- Department of Physiology, Shenzhen University Health Science Center, Shenzhen University, China (Y.S., X.L.)
| | - A H Jan Danser
- From the Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands (Y.S., A.G.M., I.M.G., A.H.J.D.)
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Abstract
PURPOSE OF REVIEW Megalin is well known for its role in the reabsorption of proteins from the ultrafiltrate. Recent studies suggest that megalin also reabsorbs renin and angiotensinogen. Indeed, without megalin urinary renin and angiotensinogen levels massively increase, and even prorenin becomes detectable in urine. RECENT FINDINGS Intriguingly, megalin might also contribute to renal angiotensin production, as evidenced from studies in megalin knockout mice. This review discusses these topics critically, concluding that urinary renin-angiotensin system components reflect diminished reabsorption rather than release from renal tissue sites and that alterations in renal renin levels or megalin-dependent signaling need to be ruled out before concluding that angiotensin production at renal tissue sites is truly megalin dependent. Future studies should evaluate megalin-mediated renin/angiotensinogen transcytosis (allowing interstitial angiotensin generation), and determine whether megalin prefers prorenin over renin, thus explaining why urine normally contains no prorenin.
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Affiliation(s)
- Yuan Sun
- Department of Internal Medicine, Division of Pharmacology and Vascular Medicine, Erasmus MC, room EE1418b, Wytemaweg 80, 3015 CN, Rotterdam, The Netherlands
- Department of Physiology, Shenzhen University Health Science Center, Shenzhen University, Shenzhen, China
- Translational Medicine Collaborative Innovation Center, The Second Clinical Medical College (Shenzhen People's Hospital) of Jinan University, Shenzhen, China
| | - Xifeng Lu
- Department of Physiology, Shenzhen University Health Science Center, Shenzhen University, Shenzhen, China
| | - A H Jan Danser
- Department of Internal Medicine, Division of Pharmacology and Vascular Medicine, Erasmus MC, room EE1418b, Wytemaweg 80, 3015 CN, Rotterdam, The Netherlands.
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Abstract
The (pro)renin receptor ((P)RR) was first identified as a single-transmembrane receptor in human kidneys and initially attracted attention owing to its potential role as a regulator of the tissue renin-angiotensin system (RAS). Subsequent studies found that the (P)RR is widely distributed in organs throughout the body, including the kidneys, heart, brain, eyes, placenta and the immune system, and has multifaceted functions in vivo. The (P)RR has roles in various physiological processes, such as the cell cycle, autophagy, acid-base balance, energy metabolism, embryonic development, T cell homeostasis, water balance, blood pressure regulation, cardiac remodelling and maintenance of podocyte structure. These roles of the (P)RR are mediated by its effects on important biological systems and pathways including the tissue RAS, vacuolar H+-ATPase, Wnt, partitioning defective homologue (Par) and tyrosine phosphorylation. In addition, the (P)RR has been reported to contribute to the pathogenesis of diseases such as fibrosis, hypertension, pre-eclampsia, diabetic microangiopathy, acute kidney injury, cardiovascular disease, cancer and obesity. Current evidence suggests that the (P)RR has key roles in the normal development and maintenance of vital organs and that dysfunction of the (P)RR is associated with diseases that are characterized by a disruption of the homeostasis of physiological functions.
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Lee JH, Jang SJ, Rhie S. Antinatriuretic phenomena seen in children with acute pyelonephritis may be related to the activation of intrarenal RAAS. Medicine (Baltimore) 2018; 97:e12152. [PMID: 30200111 PMCID: PMC6133464 DOI: 10.1097/md.0000000000012152] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We investigated whether antinatriuretic phenomena [decreases in urinary sodium (uNa) and fractional excretion of sodium (FENa)] seen in children with acute pyelonephritis (APN) are associated with the renin-angiotensin-aldosterone system (RAAS).We examined 114 children experiencing their first episode of febrile urinary tract infection (fUTI) consecutively admitted to our hospital from July 2012 to June 2014. Blood tests [C-reactive protein, white blood cell count, erythrocyte sedimentation rate, and aldosterone (Aldo)] and urine tests [uNa, urine potassium (uK) and FENa] were performed upon admission. All enrolled children underwent a 99m-dimercaptosuccinic acid renal scanning (DMSA) at admission. Areas with cortical defects (AreaCD) and uptake counts (UptakeCD) on their DMSA scans were calculated. Data were compared between children with positive DMSA results (APN), lower urinary tract infection (L-UTI), and controls; and between children with high and low Aldo levels.uNa, uNa/K, and FENa negatively correlated with AreaCD%, UptakeCD, and Aldo; were significantly lower in APN patients than in LUTIs and controls regardless of Aldo level; were lower in the high Aldo group than in the low Aldo group. However, there is no difference in AreaCD% and UptakeCD between APN children with the high and low Aldo level.Decreases in uNa, uNa/K, and FENa in children with APN may result from an antinatriuretic effect of RAAS and be related to the activation of the intrarenal RAAS.
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Affiliation(s)
| | - Su Jin Jang
- Department of Nuclear Medicine, CHA Bundang Medical Center, CHA University, Seongnam, South Korea
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Tojo A, Hatakeyama S, Nangaku M, Ishimitsu T. H +-ATPase blockade reduced renal gluconeogenesis and plasma glucose in a diabetic rat model. Med Mol Morphol 2018; 51:89-95. [PMID: 29318388 PMCID: PMC5960008 DOI: 10.1007/s00795-017-0175-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/15/2017] [Indexed: 01/05/2023]
Abstract
Vacuolar H+-adenosine triphosphatase (ATPase) plays important roles in urinary acid excretion, vesicular acidification to activate enzymes, and the membrane recycling of transporters in the kidney. As acidosis stimulates renal gluconeogenesis, we investigated the effect of blockade of H+-ATPase on renal gluconeogenesis in diabetic rats. Diabetes mellitus was induced by a single injection of streptozotocin, and a group of DM rats was treated with bafilomycin B1 intraperitoneally for 8 days. In diabetic rats, the renal expression and activity of H+-ATPase were increased with elevated urinary ammonium excretion. The blockade of H+-ATPase by bafilomycin B1 reduced the renal H+-ATPase activity and urinary ammonium excretion in diabetic rats. Treatment with bafilomycin suppressed the enhancement of the renal gluconeogenesis enzymes phosphoenol pyruvate carboxykinase and glucose-6-phosphatase in diabetic rats and reduced the renal cytoplasmic glucose levels, whereas hepatic gluconeogenesis did not change significantly. After a 24-h starvation period, bafilomycin decreased the plasma glucose level to a normal level in diabetic rats. The suppression of renal gluconeogenesis by an H+-ATPase inhibitor may therefore be a new therapeutic target for the treatment of diabetes mellitus.
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Affiliation(s)
- Akihiro Tojo
- Department of Cardiology and Nephrology, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Tochigi, 321-0293, Japan.
- Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan.
| | - Saaya Hatakeyama
- Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - Toshihiko Ishimitsu
- Department of Cardiology and Nephrology, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Tochigi, 321-0293, Japan
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9
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Labazi H, Teng B, Mustafa SJ. Functional changes in vascular reactivity to adenosine receptor activation in type I diabetic mice. Eur J Pharmacol 2017; 820:191-197. [PMID: 29269016 DOI: 10.1016/j.ejphar.2017.12.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/12/2017] [Accepted: 12/15/2017] [Indexed: 12/15/2022]
Abstract
Activation of adenosine receptors has been implicated in several biological functions, including cardiovascular and renal function. Diabetes causes morphological and functional changes in the vasculature, resulting in abnormal responses to various stimuli. Recent studies have suggested that adenosine receptor expression and signaling are altered in disease states such as hypertension, diabetes. Using a streptozotocin (STZ) mouse model of type I diabetes (T1D), we investigated the functional changes in aorta and resistance mesenteric arteries to adenosine receptor agonist activation in T1D. Organ baths and DMT wire myographs were used for muscle tension measurements in isolated vascular rings, and western blotting was used for protein analysis. Concentration response curves to selective adenosine receptor agonists, including CCPA (A1 receptor agonist), Cl-IBMECA (A3 receptor agonist), CGS-21680 (A2A receptor agonist), and BAY 60-6583 (A2B receptor agonist), were performed. We found that diabetes did not affect adenosine receptor agonist-mediated relaxation or contraction in mesenteric arteries. However, aortas from diabetic mice exhibited a significant decrease (P < 0.05) in A1 receptor-mediated vasoconstriction. In addition, the aortas from STZ-treated mice exhibited an increase in phenylephrine-mediated contraction (EC50 7.40 ± 0.08 in STZ vs 6.89 ± 0.14 in vehicle; P < 0.05), while relaxation to A2A receptor agonists (CGS-21680) tended to decrease in aortas from the STZ-treated group (not statistically significant). Our data suggest that changes in adenosine receptor(s) vascular reactivity in T1D is tissue specific, and the decrease in A1 receptor-mediated aortic contraction could be a compensatory mechanism to counterbalance the increased adrenergic vascular contractility observed in aortas from diabetic mice.
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Affiliation(s)
- Hicham Labazi
- Department of Physiology, Pharmacology and Neuroanatomy, West Virginia University, Morgantown, WV, USA.
| | - Bunyen Teng
- Department of Physiology, Pharmacology and Neuroanatomy, West Virginia University, Morgantown, WV, USA.
| | - S Jamal Mustafa
- Department of Physiology, Pharmacology and Neuroanatomy, West Virginia University, Morgantown, WV, USA; WV Center for Tranlational Science Institute, Morgantown, WV, USA.
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Novel reno-protective mechanism of Aspirin involves H2AK119 monoubiquitination and Set7 in preventing type 1 diabetic nephropathy. Pharmacol Rep 2017; 70:497-502. [PMID: 29656179 DOI: 10.1016/j.pharep.2017.11.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 11/21/2017] [Accepted: 11/27/2017] [Indexed: 12/16/2022]
Abstract
BACKGROUND Even after several novel therapeutic approaches, the number of people with diabetic nephropathy (DN) still continues to increase globally, this suggest to find novel therapeutic strategies to prevent it completely. Recent reports, are indicating the ubiquitin proteasome system alterations in DN. Recently, we also showed that, histone H2AK119 mono-ubiquitination (H2AK119-Ub) found to regulate Set7, a key epigenetic enzyme in the development of renal fibrosis under type 1 diabetic condition. Hence, we aimed to study the role of a known 20s proteasome inhibitor Aspirin, on histone ubiquitination in the progression of DN. METHODS Male Wistar rats were rendered diabetic using a single dose of Streptozotocin (55mgkg-1, ip). After 4 weeks, diabetic animals were grouped into respective groups and the drug, aspirin, low dose (25mgkg-1day-1), high dose (50mgkg-1day-1) was administered through po route. At the end of the study, kidneys from all the groups were collected and processed separately for glomerular isolation, protein isolation, and for histopathological studies. RESULTS Aspirin administration, reduced the protein expression of Mysm1, increased the protein expression of H2AK119-Ub and thereby reduced the Set7 protein expression in glomeruli isolated from diabetic animals and prevented renal fibrosis. CONCLUSIONS In conclusion, our results are clearly indicating that, aspirin prevents renal fibrosis in diabetic animals through decreasing the expression of Mysm1, increasing the expression of H2AK119-Ub and thereby decreasing the protein expression of Set7, which is a novel mechanism. Moreover, this mechanism may lay down a novel strategy to prevent DN completely in future.
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Yamazaki M, Fukusumi Y, Kayaba M, Kitazawa Y, Takamura S, Narita I, Kawachi H. Possible role for glomerular-derived angiotensinogen in nephrotic syndrome. J Renin Angiotensin Aldosterone Syst 2016; 17:17/4/1470320316681223. [PMID: 27932705 PMCID: PMC5843942 DOI: 10.1177/1470320316681223] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 10/28/2016] [Indexed: 01/13/2023] Open
Abstract
Background and objective: Renin–angiotensin system (RAS) inhibitors reduce glomerular injury and proteinuria, indicating that angiotensin II (Ang II) is involved in glomerular diseases. Although the local RAS is reported to play an essential role in maintaining local tissue functions, the role of the local RAS in regulating glomerular function is not well evaluated. In this study, we analyzed the glomerular expression of RAS components in nephrotic models and the effect of Ang II receptor blockers (ARB) on the expression of angiotensinogen (AGT). Methods: The levels of glomerular expression of RAS components were analyzed in two nephrotic models: anti-nephrin antibody-induced nephropathy and PAN nephropathy, a mimic of human minimal change nephrotic syndrome. The effect of the ARB irbesartan on the expression of AGT in the nephrotic model was analyzed. Results: Glomerular expression of AGT and the receptors for Ang II was clearly increased in the nephrotic models, while the expression levels of renin, ACE and ACE2 were decreased. ARB treatment suppressed the increase of glomerular expression of AGT in the nephrotic model. Conclusion: It is conceivable that the promoted local RAS action participated in the glomerular dysfunction, and that ARB treatment ameliorated slit diaphragm injury by inhibiting the positive feedback loop of the activated local Ang II action.
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Affiliation(s)
- Mihoko Yamazaki
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Japan.,Department of Nephrology and Rheumatology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Japan
| | - Yoshiyasu Fukusumi
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Japan
| | - Mutsumi Kayaba
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Japan
| | - Yukina Kitazawa
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Japan
| | - Sayuri Takamura
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Japan
| | - Ichiei Narita
- Department of Nephrology and Rheumatology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Japan
| | - Hiroshi Kawachi
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Japan
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Wilson BA, Cruz-Diaz N, Su Y, Rose JC, Gwathmey TM, Chappell MC. Angiotensinogen import in isolated proximal tubules: evidence for mitochondrial trafficking and uptake. Am J Physiol Renal Physiol 2016; 312:F879-F886. [PMID: 27903492 PMCID: PMC5451555 DOI: 10.1152/ajprenal.00246.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 11/11/2016] [Accepted: 11/23/2016] [Indexed: 12/15/2022] Open
Abstract
The renal proximal tubules are a key functional component of the kidney and express the angiotensin precursor angiotensinogen; however, it is unclear the extent that tubular angiotensinogen reflects local synthesis or internalization. Therefore, the current study established the extent to which angiotensinogen is internalized by proximal tubules and the intracellular distribution. Proximal tubules were isolated from the kidney cortex of male sheep by enzymatic digestion and a discontinuous Percoll gradient. Tubules were incubated with radiolabeled 125I-angiotensinogen for 2 h at 37°C in serum/phenol-free DMEM/F12 media. Approximately 10% of exogenous 125I-angiotensinogen was internalized by sheep tubules. Subcellular fractionation revealed that 21 ± 4% of the internalized 125I-angiotensinogen associated with the mitochondrial fraction with additional labeling evident in the nucleus (60 ± 7%), endoplasmic reticulum (4 ± 0.5%), and cytosol (15 ± 4%; n = 4). Subsequent studies determined whether mitochondria directly internalized 125I-angiotensinogen using isolated mitochondria from renal cortex and human HK-2 proximal tubule cells. Sheep cortical and HK-2 mitochondria internalized 125I-angiotensinogen at a comparable rate of (33 ± 9 vs. 21 ± 10 pmol·min-1·mg protein-1; n = 3). Lastly, unlabeled angiotensinogen (100 nM) competed for 125I-angiotensinogen uptake to a greater extent than human albumin in HK-2 mitochondria (60 ± 2 vs. 16 ± 13%; P < 0.05, n = 3). Collectively, our data demonstrate angiotensinogen import and subsequent trafficking to the mitochondria in proximal tubules. We conclude that this pathway may constitute a source of the angiotensinogen precursor for the mitochondrial expression of angiotensin peptides.
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Affiliation(s)
- Bryan A Wilson
- Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, North Carolina; and
| | - Nildris Cruz-Diaz
- Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, North Carolina; and
| | - Yixin Su
- Department of Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - James C Rose
- Department of Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - TanYa M Gwathmey
- Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, North Carolina; and
| | - Mark C Chappell
- Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, North Carolina; and
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Therapeutic evaluation of rutin in two-kidney one-clip model of renovascular hypertension in rat. Life Sci 2016; 150:89-94. [PMID: 26920631 DOI: 10.1016/j.lfs.2016.02.080] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 02/19/2016] [Accepted: 02/22/2016] [Indexed: 12/31/2022]
Abstract
AIM The current investigation, designed to investigate the role of rutin in two-kidney one-clip (2K1C) induced renovascular dysfunction associated with hypertension in rat. MAIN METHODS The renovascular hypertension was developed by the application of vascular clip on left renal artery in rats; the right kidney was kept as such throughout the experimental protocol. The rutin (200 and 300 mg/kg; p.o.) and aliskiren (50mg/kg; p.o.) were administered for 9 consecutive days. The battery of pathophysiological tests i.e., systolic pressure, diastolic pressure and heart rate were performed to assess the anti-hypertensive effect of rutin. In addition, changes of kidney weight/body weight (KW/BW) ratio along with plasma renin content and renal tissue biomarkers i.e., thiobarbituric acid reactive substance (TBAR) and reduced glutathione (GSH) levels were estimated. KEY FINDINGS The administration of rutin significantly (P<0.05) attenuated the 2K1C of left kidney induced elevated systolic and diastolic pressure in a dose dependent manner. In addition, it also reduces the ratio of KW/BW along with a decrease in plasma renin content, tissue TBARS and increase the GSH levels. There were no significant changes observed in heart rate. Similar results were observed in aliskiren treated group. SIGNIFICANCE The anti-hypertensive effect of rutin may be a useful herbal medicine for the management of hypertension due to its potential free radical scavenging, inhibition of lipid peroxidation and plasma renin inhibitory action.
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