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Ma R, Tao Y, Wade ML, Mallet RT. Non-voltage-gated Ca 2+ channel signaling in glomerular cells in kidney health and disease. Am J Physiol Renal Physiol 2024; 327:F249-F264. [PMID: 38867675 PMCID: PMC11460346 DOI: 10.1152/ajprenal.00130.2024] [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: 04/29/2024] [Revised: 06/10/2024] [Accepted: 06/10/2024] [Indexed: 06/14/2024] Open
Abstract
Positioned at the head of the nephron, the renal corpuscle generates a plasma ultrafiltrate to initiate urine formation. Three major cell types within the renal corpuscle, the glomerular mesangial cells, podocytes, and glomerular capillary endothelial cells, communicate via endocrine- and paracrine-signaling mechanisms to maintain the structure and function of the glomerular capillary network and filtration barrier. Ca2+ signaling mediated by several distinct plasma membrane Ca2+ channels impacts the functions of all three cell types. The past two decades have witnessed pivotal advances in understanding of non-voltage-gated Ca2+ channel function and regulation in the renal corpuscle in health and renal disease. This review summarizes the current knowledge of the physiological and pathological impact of non-voltage-gated Ca2+ channel signaling in mesangial cells, podocytes and glomerular capillary endothelium. The main focus is on transient receptor potential and store-operated Ca2+ channels, but ionotropic N-methyl-d-aspartate receptors and purinergic receptors also are discussed. This update of Ca2+ channel functions and their cellular signaling cascades in the renal corpuscle is intended to inform the development of therapeutic strategies targeting these channels to treat kidney diseases, particularly diabetic nephropathy.
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Affiliation(s)
- Rong Ma
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Yu Tao
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Michael L Wade
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Robert T Mallet
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States
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Staruschenko A, Ma R, Palygin O, Dryer SE. Ion channels and channelopathies in glomeruli. Physiol Rev 2023; 103:787-854. [PMID: 36007181 PMCID: PMC9662803 DOI: 10.1152/physrev.00013.2022] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/15/2022] [Accepted: 08/21/2022] [Indexed: 11/22/2022] Open
Abstract
An essential step in renal function entails the formation of an ultrafiltrate that is delivered to the renal tubules for subsequent processing. This process, known as glomerular filtration, is controlled by intrinsic regulatory systems and by paracrine, neuronal, and endocrine signals that converge onto glomerular cells. In addition, the characteristics of glomerular fluid flow, such as the glomerular filtration rate and the glomerular filtration fraction, play an important role in determining blood flow to the rest of the kidney. Consequently, disease processes that initially affect glomeruli are the most likely to lead to end-stage kidney failure. The cells that comprise the glomerular filter, especially podocytes and mesangial cells, express many different types of ion channels that regulate intrinsic aspects of cell function and cellular responses to the local environment, such as changes in glomerular capillary pressure. Dysregulation of glomerular ion channels, such as changes in TRPC6, can lead to devastating glomerular diseases, and a number of channels, including TRPC6, TRPC5, and various ionotropic receptors, are promising targets for drug development. This review discusses glomerular structure and glomerular disease processes. It also describes the types of plasma membrane ion channels that have been identified in glomerular cells, the physiological and pathophysiological contexts in which they operate, and the pathways by which they are regulated and dysregulated. The contributions of these channels to glomerular disease processes, such as focal segmental glomerulosclerosis (FSGS) and diabetic nephropathy, as well as the development of drugs that target these channels are also discussed.
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Affiliation(s)
- Alexander Staruschenko
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida
- Hypertension and Kidney Research Center, University of South Florida, Tampa, Florida
- James A. Haley Veterans Hospital, Tampa, Florida
| | - Rong Ma
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Oleg Palygin
- Division of Nephrology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Stuart E Dryer
- Department of Biology and Biochemistry, University of Houston, Houston, Texas
- Department of Biomedical Sciences, Tilman J. Fertitta Family College of Medicine, University of Houston, Houston, Texas
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Huynh L, Rodriguez-Lopez S, Benisty K, Dancea A, Garros D, Hessey E, Joffe A, Joffe R, Mackie A, Palijan A, Paun A, Pizzi M, Zappitelli M, Morgan C. Follow-up after neonatal heart disease repair: watch out for chronic kidney disease and hypertension! Pediatr Nephrol 2020; 35:2137-2145. [PMID: 32500246 PMCID: PMC7515960 DOI: 10.1007/s00467-020-04621-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 05/01/2020] [Accepted: 05/19/2020] [Indexed: 01/22/2023]
Abstract
BACKGROUND With advances in care, neonates undergoing cardiac repairs are surviving more frequently. Our objectives were to 1) estimate the prevalence of chronic kidney disease (CKD) and hypertension 6 years after neonatal congenital heart surgery and 2) determine if cardiac surgery-associated acute kidney injury (CS-AKI) is associated with these outcomes. METHODS Two-center prospective, longitudinal single-visit cohort study including children with congenital heart disease surgery as neonates between January 2005 and December 2012. CKD (estimated glomerular filtration rate < 90 mL/min/1.73m2 or albumin/creatinine ≥3 mg/mmol) and hypertension (systolic or diastolic blood pressure ≥ 95th percentile for age, sex, and height) prevalence 6 years after surgery was estimated. The association of CS-AKI (Kidney Disease: Improving Global Outcomes definition) with CKD and hypertension was determined using multiple regression. RESULTS Fifty-eight children with median follow-up of 6 years were evaluated. CS-AKI occurred in 58%. CKD and hypertension prevalence were 17% and 30%, respectively; an additional 15% were classified as having elevated blood pressure. CS-AKI was not associated with CKD or hypertension. Classification as cyanotic postoperatively was the only independent predictor of CKD. Postoperative days in hospital predicted hypertension at follow-up. CONCLUSIONS The prevalence of CKD and hypertension is high in children having neonatal congenital heart surgery. This is important; early identification of CKD and hypertension can improve outcomes. These children should be systematically followed for the evolution of these negative outcomes. CS-AKI defined by current standards may not be a useful clinical tool to decide who needs follow-up and who does not.
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Affiliation(s)
- Louis Huynh
- Faculty of Health Sciences, School of Medicine, Queen's University, Kingston, ON, Canada
| | - Sara Rodriguez-Lopez
- Department of Pediatrics, Division of Nephrology, University of Alberta, Stollery Children's Hospital, Room 4-555, 11405-87 Avenue, Edmonton, AB, T6G 1C9, Canada
| | - Kelly Benisty
- Faculty of Medicine, McGill University, Montreal, QC, Canada
| | - Adrian Dancea
- Department of Pediatrics, Division of Cardiology, Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada
| | - Daniel Garros
- Department of Pediatrics, Division of Pediatric Critical Care, University of Alberta, Edmonton, AB, Canada
| | - Erin Hessey
- Faculty of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Ari Joffe
- Department of Pediatrics, Division of Pediatric Critical Care, University of Alberta, Edmonton, AB, Canada
| | - Rachel Joffe
- Faculty of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Andrew Mackie
- Department of Pediatrics, Division of Cardiology, University of Alberta, Edmonton, AB, Canada
| | - Ana Palijan
- McGill University Health Centre Research Institute, McGill University Health Centre, Montreal, QC, Canada
| | - Alex Paun
- McGill University Health Centre Research Institute, McGill University Health Centre, Montreal, QC, Canada
| | - Michael Pizzi
- McGill University Health Centre Research Institute, McGill University Health Centre, Montreal, QC, Canada
| | - Michael Zappitelli
- Department of Pediatrics, Division of Nephrology, Peter Gilgan Centre for Research and Learning, Toronto Hospital for Sick Children, 686 Bay Street, Room 6th floor 9708, Toronto, ON, M5G 0A4, Canada.
| | - Catherine Morgan
- Department of Pediatrics, Division of Nephrology, University of Alberta, Stollery Children's Hospital, Room 4-555, 11405-87 Avenue, Edmonton, AB, T6G 1C9, Canada.
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Keeley TP, Siow RCM, Jacob R, Mann GE. Reduced SERCA activity underlies dysregulation of Ca 2+ homeostasis under atmospheric O 2 levels. FASEB J 2017; 32:2531-2538. [PMID: 29273673 PMCID: PMC5901376 DOI: 10.1096/fj.201700685rrr] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Unregulated increases in cellular Ca2+ homeostasis are a hallmark of pathophysiological conditions and a key trigger of cell death. Endothelial cells cultured under physiologic O2 conditions (5% O2) exhibit a reduced cytosolic Ca2+ response to stimulation. The mechanism for reduced plateau [Ca2+]i upon stimulation was due to increased sarco/endoplasmic reticulum Ca2+ ATPase (SERCA)-mediated reuptake rather than changes in Ca2+ influx capacity. Agonist-stimulated phosphorylation of the SERCA regulatory protein phospholamban was increased in cells cultured under 5% O2. Elevation of cytosolic and mitochondrial [Ca2+] and cell death after prolonged ionomycin treatment, as a model of Ca2+ overload, were lower when cells were cultured long-term under 5% compared with 18% O2. This protection was abolished by cotreatment with the SERCA inhibitor cyclopiazonic acid. Taken together, these results demonstrate that culturing cells under hyperoxic conditions reduces their ability to efficiently regulate [Ca2+]i, resulting in greater sensitivity to cytotoxic stimuli.-Keeley, T. P., Siow, R. C. M., Jacob, R., Mann, G. E. Reduced SERCA activity underlies dysregulation of Ca2+ homeostasis under atmospheric O2 levels.
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Affiliation(s)
- Thomas P Keeley
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine and Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Richard C M Siow
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine and Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Ron Jacob
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine and Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Giovanni E Mann
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine and Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
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Morgan C, Al-Aklabi M, Garcia Guerra G. Chronic kidney disease in congenital heart disease patients: a narrative review of evidence. Can J Kidney Health Dis 2015; 2:27. [PMID: 26266042 PMCID: PMC4531493 DOI: 10.1186/s40697-015-0063-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 07/09/2015] [Indexed: 11/10/2022] Open
Abstract
Purpose of review Patients with congenital heart disease have a number of risk factors for the development of chronic kidney disease (CKD). It is well known that CKD has a large negative impact on health outcomes. It is important therefore to consider that patients with congenital heart disease represent a population in whom long-term primary and secondary prevention strategies to reduce CKD occurrence and progression could be instituted and significantly change outcomes. There are currently no clear guidelines for clinicians in terms of renal assessment in the long-term follow up of patients with congenital heart disease. Consolidation of knowledge is critical for generating such guidelines, and hence is the purpose of this view. This review will summarize current knowledge related to CKD in patients with congenital heart disease, to highlight important work that has been done to date and set the stage for further investigation, development of prevention strategies, and re-evaluation of appropriate renal follow-up in patients with congenital heart disease. Sources of information The literature search was conducted using PubMed and Google Scholar. Findings Current epidemiological evidence suggests that CKD occurs in patients with congenital heart disease at a higher frequency than the general population and is detectable early in follow-up (i.e. during childhood). Best evidence suggests that approximately 30 to 50 % of adult patients with congenital heart disease have significantly impaired renal function. The risk of CKD is higher with cyanotic congenital heart disease but it is also present with non-cyanotic congenital heart disease. Although significant knowledge gaps exist, the sum of the data suggests that patients with congenital heart disease should be followed from an early age for the development of CKD. Implications There is an opportunity to mitigate CKD progression and negative renal outcomes by instituting interventions such as stringent blood pressure control and reduction of proteinuria. There is a need to invest time, thought and money to fill existing knowledge gaps to improve health outcomes in this population. This review should serve as an impetus for generation of follow-up guidelines of kidney health evaluation in patients with congenital heart disease.
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Affiliation(s)
- Catherine Morgan
- Division of Nephrology, Department of Pediatrics, 4-557 Edmonton Clinic Health Academy, 11405 - 87 Avenue, Edmonton, AB T6G 1C9 Canada
| | - Mohammed Al-Aklabi
- Division of Cardiac Surgery, Department of Medicine, 4A7.C Mazankowski Heart Institute, 8440 - 112 Street, Edmonton, AB T6G 2B7 Canada
| | - Gonzalo Garcia Guerra
- Division of Pediatric Critical Care, Department of Pediatrics, 4-548 Edmonton Clinic Health Academy, 11405 - 87 Avenue, Edmonton, AB T6G 1C9 Canada
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Gorospe M, Tominaga K, Wu X, Fähling M, Ivan M. Post-Transcriptional Control of the Hypoxic Response by RNA-Binding Proteins and MicroRNAs. Front Mol Neurosci 2011; 4:7. [PMID: 21747757 PMCID: PMC3130151 DOI: 10.3389/fnmol.2011.00007] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 06/17/2011] [Indexed: 01/08/2023] Open
Abstract
Mammalian gene expression patterns change profoundly in response to low oxygen levels. These changes in gene expression programs are strongly influenced by post-transcriptional mechanisms mediated by mRNA-binding factors: RNA-binding proteins (RBPs) and microRNAs (miRNAs). Here, we review the RBPs and miRNAs that modulate mRNA turnover and translation in response to hypoxic challenge. RBPs such as HuR (human antigen R), PTB (polypyrimidine tract-binding protein), heterogeneous nuclear ribonucleoproteins (hnRNPs), tristetraprolin, nucleolin, iron-response element-binding proteins (IRPs), and cytoplasmic polyadenylation-element-binding proteins (CPEBs), selectively bind to numerous hypoxia-regulated transcripts and play a major role in establishing hypoxic gene expression patterns. MiRNAs including miR-210, miR-373, and miR-21 associate with hypoxia-regulated transcripts and further modulate the levels of the encoded proteins to implement the hypoxic gene expression profile. We discuss the potent regulation of hypoxic gene expression by RBPs and miRNAs and their integrated actions in the cellular hypoxic response.
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Affiliation(s)
- Myriam Gorospe
- Laboratory of Molecular Biology and Immunology, National Institute on Aging-Intramural Research Program, National Institutes of HealthBaltimore, MD, USA
| | - Kumiko Tominaga
- Laboratory of Molecular Biology and Immunology, National Institute on Aging-Intramural Research Program, National Institutes of HealthBaltimore, MD, USA
| | - Xue Wu
- Department of Medicine, Indiana University School of MedicineIndianapolis, IN, USA
| | - Michael Fähling
- Institut für Vegetative Physiologie, Campus Charité Mitte, Charité – Universitätsmedizin BerlinBerlin, Germany
| | - Mircea Ivan
- Department of Medicine, Indiana University School of MedicineIndianapolis, IN, USA
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Abstract
In cells responding to low oxygen levels, gene expression patterns are strongly influenced by post-transcriptional processes. RNA-binding proteins (RBPs) are pivotal regulators of gene expression in response to numerous stresses, including hypoxia. Here, we review the RBPs that modulate mRNA turnover and translation in response to hypoxic challenge. The RBPs HuR (human antigen R) and PTB (polypyrimidine tract-binding protein) associate with mRNAs encoding hypoxia-response proteins such as HIF-1α and VEGF mRNAs, enhance their expression after hypoxia and play a major role in establishing hypoxic gene expression patterns. Additional RBPs such as iron-response element-binding proteins (IRPs), cytoplasmic polyadenylation-element-binding proteins (CPEBs) and several heterogeneous nuclear ribonucleoproteins (hnRNPs) also bind to hypoxia-regulated transcripts and modulate the levels of the encoded proteins. We discuss the efficient regulation of hypoxic gene expression by RBPs and the mounting interest in targeting hypoxia-regulatory RBPs in diseases with aberrant hypoxic responses.
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Affiliation(s)
- Kiyoshi Masuda
- Laboratory of Cellular and Molecular Biology, National Institute on Aging-Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
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Mizuno S, Bogaard HJ, Voelkel NF, Umeda Y, Kadowaki M, Ameshima S, Miyamori I, Ishizaki T. Hypoxia regulates human lung fibroblast proliferation via p53-dependent and -independent pathways. Respir Res 2009; 10:17. [PMID: 19267931 PMCID: PMC2663549 DOI: 10.1186/1465-9921-10-17] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Accepted: 03/06/2009] [Indexed: 11/16/2022] Open
Abstract
Background Hypoxia induces the proliferation of lung fibroblasts in vivo and in vitro. However, the subcellular interactions between hypoxia and expression of tumor suppressor p53 and cyclin-dependent kinase inhibitors p21 and p27 remain unclear. Methods Normal human lung fibroblasts (NHLF) were cultured in a hypoxic chamber or exposed to desferroxamine (DFX). DNA synthesis was measured using bromodeoxyuridine incorporation, and expression of p53, p21 and p27 was measured using real-time RT-PCR and Western blot analysis. Results DNA synthesis was increased by moderate hypoxia (2% oxygen) but was decreased by severe hypoxia (0.1% oxygen) and DFX. Moderate hypoxia decreased p21 synthesis without affecting p53 synthesis, whereas severe hypoxia and DFX increased synthesis of both p21 and p53. p27 protein expression was decreased by severe hypoxia and DFX. Gene silencing of p21 and p27 promoted DNA synthesis at ambient oxygen concentrations. p21 and p53 gene silencing lessened the decrease in DNA synthesis due to severe hypoxia or DFX exposure. p21 gene silencing prevented increased DNA synthesis in moderate hypoxia. p27 protein expression was significantly increased by p53 gene silencing, and was decreased by wild-type p53 gene transfection. Conclusion These results indicate that in NHLF, severe hypoxia leads to cell cycle arrest via the p53-p21 pathway, but that moderate hypoxia enhances cell proliferation via the p21 pathway in a p53-independent manner. In addition, our results suggest that p27 may be involved in compensating for p53 in cultured NHLF proliferation.
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Affiliation(s)
- Shiro Mizuno
- Third Department of Internal Medicine, University of Fukui, Yoshida-gun, Fukui, Japan.
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Lee YK, Kim EJ, Lee JE, Noh JW, Kim YG. Hypoxia induces connective tissue growth factor mRNA expression. J Korean Med Sci 2009; 24 Suppl:S176-82. [PMID: 19194549 PMCID: PMC2633197 DOI: 10.3346/jkms.2009.24.s1.s176] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Accepted: 11/19/2008] [Indexed: 11/20/2022] Open
Abstract
Connective tissue growth factor (CTGF) is known to be a profibrotic growth factor, which mediate the fibrotic effect of transforming growth factor-beta (TGF-beta) and to stimulate cell proliferation and matrix production. CTGF has been shown to be hypoxia-inducible in several cell types. Here we investigated the effect of hypoxia on CTGF gene expression in cultured mouse renal tubular cells (MTC). Quiescent cultures of MTC were exposed to hypoxia (1% O(2)) or normoxia in serum-free medium. The effects on hypoxia-induced CTGF expression were evaluated by Northern blot and real-time PCR. The roles of mitogen-activated protein kinase (MAPK) and TGF-beta were also determined using specific biochemical inhibitors. Exposure of quiescent tubular cells to hypoxia for 24 hr in a conditioned medium resulted in a significant increase TGF-beta. Hypoxia caused a significant increase in CTGF mRNA expression in MTC. Either JNK or ERK inhibitor did not block the hypoxia-induced stimulation of CTGF, whereas an inhibitor of p38 MAPK reduced the hypoxia-induced changes of CTGF. Although hypoxia stimulated TGF-beta production, neutralizing anti-TGF-beta1 antibody did not abolish the hypoxia-induced CTGF mRNA expression. The data suggest that hypoxia up-regulates CTGF gene expression, and that p38 MAPK plays a role in hypoxic-stimulation of CTGF. We also demonstrated that hypoxia induces CTGF mRNA expression via a TGF-beta1-independent mechanism.
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Affiliation(s)
- Young Ki Lee
- Department of Internal Medicine, Hallym University, Seoul, Korea
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Câmpean V, Karpe B, Haas C, Atalla A, Peters H, Rupprecht H, Liebner S, Acker T, Plate K, Amann K. Angiopoietin 1 and 2 gene and protein expression is differentially regulated in acute anti-Thy1.1 glomerulonephritis. Am J Physiol Renal Physiol 2008; 294:F1174-84. [DOI: 10.1152/ajprenal.00320.2007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Capillary neoformation is important in repair of glomerular injury of various origins. VEGF was shown to be crucial for glomerular capillary repair in glomerulonephritis (GN). We reasoned that other angiogenic factors are likewise involved in glomerular capillary remodeling and found angiopoietin 1 and -2 (ANG1 and ANG2) mRNA to be upregulated in cDNA microarrays of microdissected glomeruli of anti-Thy1.1 GN of the rat. We then studied glomerular in situ gene and protein expression of ANG1 and ANG2 and their receptor Tie-2 in the course of anti-Thy1.1 GN, which was induced by injection of OX-7 antibody. Animals were perfusion fixed at days 6 and 12 after GN induction and compared with nonnephritic controls receiving PBS. Capillary damage and repair were quantitatively analyzed using stereological techniques. Gene and protein expression of ANG1 and ANG2 and their receptor Tie-2 was analyzed using real-time quantitative PCR from microdissected glomeruli, nonradioactive in situ hybridization, double immunofluorescence, and Western blot analysis. Glomerular capillarization assessed as length density was significantly lower at day 6 of anti-Thy1.1 GN than in controls; it was back to normal values at day 12. ANG1 and ANG2 gene expression was markedly upregulated at day 6 of the disease compared with controls. Protein expression of ANG1 and ANG2 was confined to podocytes and that of Tie-2 to endothelial cells. At day 12 of anti-Thy1.1 GN when capillary restoration was nearly completed, ANG1 and ANG2 gene expression returned to basal levels, whereas Tie-2 expression was still high. With the use of a combined molecular and in situ approach, the spatial and temporal gene and protein expression of the angiopoietins and their receptor was analyzed in anti-Thy1.1 GN. The results indicate that glomerular expression of ANG1 and ANG2 and Tie-2 is differentially regulated and may contribute to healing and endothelial cell stabilization in experimental GN.
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Kadowaki M, Mizuno S, Demura Y, Ameshima S, Miyamori I, Ishizaki T. Effect of hypoxia and Beraprost sodium on human pulmonary arterial smooth muscle cell proliferation: the role of p27kip1. Respir Res 2007; 8:77. [PMID: 17974037 PMCID: PMC2164950 DOI: 10.1186/1465-9921-8-77] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2007] [Accepted: 11/01/2007] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Hypoxia induces the proliferation of pulmonary arterial smooth muscle cell (PASMC) in vivo and in vitro, and prostacyclin analogues are thought to inhibit the growth of PASMC. Previous studies suggest that p27kip1, a kind of cyclin-dependent kinase inhibitor, play an important role in the smooth muscle cell proliferation. However, the mechanism of hypoxia and the subcellular interactions between p27kip1 and prostacyclin analogues in human pulmonary arterial smooth muscle cell (HPASMC) are not fully understood. METHODS We investigated the role of p27kip1 in the ability of Beraprost sodium (BPS; a stable prostacyclin analogue) to inhibit the proliferation of HPASMC during hypoxia. To clarify the biological effects of hypoxic air exposure and BPS on HPASMC, the cells were cultured in a hypoxic chamber under various oxygen concentrations (0.1-21%). Thereafter, DNA synthesis was measured as bromodeoxyuridine (BrdU) incorporation, the cell cycle was analyzed by flow cytometry with propidium iodide staining. The p27kip1 mRNA and protein expression and it's stability was measured by real-time RT-PCR and Western blotting. Further, we assessed the role of p27kip1 in HPASMC proliferation using p27kip1 gene knockdown using small interfering RNA (siRNA) transfection. RESULTS Although severe hypoxia (0.1% oxygen) suppressed the proliferation of serum-stimulated HPASMC, moderate hypoxia (2% oxygen) enhanced proliferation in accordance with enhanced p27kip1 protein degradation, whereas BPS suppressed HPASMC proliferation under both hypoxic and normoxic conditions by suppressing p27kip1 degradation with intracellular cAMP-elevation. The 8-bromo-cyclic adenosine monophosphate (8-Br-cAMP), a cAMP analogue, had similar action as BPS in the regulation of p27kip1. Moderate hypoxia did not affect the stability of p27kip1 protein expression, but PDGF, known as major hypoxia-induced growth factors, significantly decreased p27kip1 protein stability. We also demonstrated that BPS and 8-Br-cAMP suppressed HPASMC proliferation under both hypoxic and normoxic conditions by blocking p27kip1 mRNA degradation. Furthermore, p27kip1 gene silencing partially attenuated the effects of BPS and partially restored hypoxia-induced proliferation. CONCLUSION Our study suggests that moderate hypoxia induces HPASMC proliferation, which is partially dependent of p27kip1 down-regulation probably via the induction of growth factors such as PDGF, and BPS inhibits both the cell proliferation and p27kip1 mRNA degradation through cAMP pathway.
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Affiliation(s)
- Maiko Kadowaki
- Third Department of Internal Medicine, University of Fukui, 23-3 Eiheiji-cho, Matsuoka, Yoshida-gun, Fukui, Japan.
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Cogo A, Napolitano G, Michoud MC, Barbon DR, Ward M, Martin JG. Effects of hypoxia on rat airway smooth muscle cell proliferation. J Appl Physiol (1985) 2003; 94:1403-9. [PMID: 12626471 DOI: 10.1152/japplphysiol.00363.2002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Although it is well known that hypoxemia induces pulmonary vasoconstriction and vascular remodeling, due to the proliferation of both vascular smooth muscle cells and fibroblasts, the effects of hypoxemia on airway smooth muscle cells are not well characterized. The present study was designed to assess the in vitro effects of hypoxia (1 or 3% O(2)) on rat airway smooth muscle cell growth and response to mitogens (PDGF and 5-HT). Cell growth was assessed by cell counting and cell cycle analysis. Compared with normoxia (21% O(2)), there was a 42.2% increase in the rate of proliferation of cells exposed to 3% O(2) (72 h, P = 0.006), as well as an enhanced response to PDGF (13.9% increase; P = 0.023) and to 5-HT (17.2% increase; P = 0.039). Exposure to 1% O(2) (72 h) decreased cell proliferation by 21.0% (P = 0.017) and reduced the increase in cell proliferation induced by PGDF and 5-HT by 16.2 and 15.7%, respectively (P = 0.019 and P = 0.011). A significant inhibition in hypoxia-induced cell proliferation was observed after the administration of bisindolylmaleimide GF-109203X (a specific PKC inhibitor) or downregulation of PKC with PMA. Pretreatment with GF-109203X decreased proliferation by 21.5% (P = 0.004) and PMA by 31.5% (P = 0.005). These results show that hypoxia induces airway smooth muscle cell proliferation, which is at least partially dependent on PKC activation. They suggest that hypoxia could contribute to airway remodeling in patients suffering from chronic, severe respiratory diseases.
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Affiliation(s)
- A Cogo
- Meakins-Christie Laboratories and Montreal Chest Institute Research Center, McGill University, Montréal, Québec, Canada H2X 2P2
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Sodhi CP, Kanwar YS, Sahai A. Hypoxia and high glucose upregulate AT1 receptor expression and potentiate ANG II-induced proliferation in VSM cells. Am J Physiol Heart Circ Physiol 2003; 284:H846-52. [PMID: 12433659 DOI: 10.1152/ajpheart.00625.2002] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined the effect of hypoxia and high glucose (HG) on ANG II type 1 (AT(1)) receptor expression and proliferation in cultured vascular smooth muscle (VSM) cells. Exposure of quiescent cells to hypoxia in a serum-free DME-Ham's F-12 medium for 6-24 h induced a progressive increase in AT(1) mRNA expression. Exposure of cells to 24 h of hypoxia also resulted in a significant increase in ANG II receptor binding as assessed with (125)I-labeled ANG II. Treatment with ANG II (1 microM) for 24 h under normoxic conditions caused an approximately 1.5-fold increase in both DNA synthesis and cell number, which was enhanced to approximately 3.0-fold under hypoxic conditions. An AT(1) receptor antagonist (losartan, 10 microM) blocked the ANG II-induced increase in DNA synthesis under both normoxic and hypoxic conditions. Incubations in HG medium (25 mM) for 12-24 h under normoxic conditions induced an approximately 2.5-fold increase in AT(1) mRNA levels, which was markedly enhanced by hypoxia to approximately 5.5-fold at 12 h and approximately 8.5-fold at 24 h. ANG II under HG-normoxic conditions caused a complete downregulation of AT(1) expression, which was prevented by hypoxia. These results demonstrate an upregulation of AT(1) receptor expression by hypoxia and HG in cultured VSM cells and suggest a mechanism for enhanced ANG II-induced VSM cell proliferation and the development of atherosclerosis in diabetes.
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MESH Headings
- Angiotensin II/pharmacology
- Animals
- Blotting, Northern
- Cell Division/drug effects
- Cell Division/physiology
- Cell Hypoxia/physiology
- Cells, Cultured
- Glucose/pharmacology
- Hyperglycemia/metabolism
- Male
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptor, Angiotensin, Type 1
- Receptors, Angiotensin/genetics
- Receptors, Angiotensin/metabolism
- Up-Regulation/drug effects
- Up-Regulation/physiology
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Affiliation(s)
- Chhinder P Sodhi
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
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Parameswaran N, Hall CS, Bock BC, Sparks HV, Gallo KA, Spielman WS. Mixed lineage kinase 3 inhibits phorbol myristoyl acetate-induced DNA synthesis but not osteopontin expression in rat mesangial cells. Mol Cell Biochem 2002; 241:37-43. [PMID: 12482023 DOI: 10.1023/a:1020835106255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mixed lineage kinase 3 (MLK 3) (also called SPRK or PTK-1) is a recently described member of the family of the mixed lineage kinase subfamily of Ser/Thr protein kinases that interacts with mitogen-activated protein kinase pathways. In order to test the biological relevance and potential interaction of MLK 3 with protein kinase C-mediated signaling pathways, human MLK 3 was stably expressed in rat glomerular mesangial cells using a retroviral vector (LXSN) and the effects of phorbol myristoyl acetate (PMA) on DNA synthesis and osteopontin mRNA expression were examined. In control (vector-transfected) mesangial cells PMA increased [3H]-thymidine incorporation in a concentration-dependent manner. In mesangial cells stably expressing MLK 3, the PMA-induced increase in [3H]-thymidine incorporation was significantly reduced (> 50%). However, the PMA-induced increase in osteopontin mRNA was not affected by MLK 3 expression. To determine the mechanisms of these effects, activation of ERK2, JNK1 and p38 in response to PMA was examined in both vector and MLK 3 transfected cells. ERK2 activation was increased several fold by PMA in control cells but was attenuated significantly in MLK 3 expressing cells, suggesting that MLK 3 expression in mesangial cells can negatively regulate the ERK pathway. PMA had no significant effect on JNK and P38 activation, in either vector- or MLK 3-expressing cells. PD98059, a MEK inhibitor blocked PMA-induced DNA synthesis without affecting osteopontin expression. These results suggest that while protein kinase C activation increases cellular proliferation and osteopontin mRNA expression, over-expression of MLK 3 affects only the PKC-induced DNA synthesis, probably through inhibition of ERK. These results also indicate a novel mechanism of growth regulation by a member of the mixed-lineage kinase family that might have significant therapeutic implications in proliferative glomerulonephritis.
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Zacour ME, Teoh H, Halayko AJ, Ward ME. Mechanisms of aortic smooth muscle hyporeactivity after prolonged hypoxia in rats. J Appl Physiol (1985) 2002; 92:2625-32. [PMID: 12015382 DOI: 10.1152/japplphysiol.00818.2001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of this study was to determine whether the effects of hypoxia on aortic contractility reflect a decrease in smooth muscle activation [phosphorylation of the 20-kDa myosin regulatory light chain (LC(20))], the capacity for myofibrillar ATP hydrolysis (mATPase activity), or both. Our results indicate that, in endothelium-denuded aortic rings from rats exposed to hypoxia for 48 h (inspired O(2) concentration = 10%), contractions to phenylephrine and potassium chloride (KCl) are impaired compared with rings from normoxic rats. The proportion of phosphorylated to total LC(20) during aortic contraction induced by 10(-5) M phenylephrine was reduced after hypoxia (51.4 +/- 5.4% in normoxic control rats vs. 32.5 +/- 4.7% in hypoxic rats, P < 0.01). Aortic mATPase activity was also decreased (maximum ATPase rate = 29.6 +/- 3.4 and 20.7 +/- 3.7 nmol. min(-1). mg protein(-1) in control and hypoxic rats, respectively, P < 0.05). Neither proliferation nor dedifferentiation of aortic smooth muscle was evident in this model; immunostaining for smooth muscle expression of the proliferating cell nuclear antigen was negative and smooth muscle-specific isoforms of myosin heavy chains, h-caldesmon, and calponin were increased, not decreased, after hypoxic exposure. Decreased aortic reactivity after hypoxia is associated with both impairment of smooth muscle activation and diminished capacity of the actomyosin complex, once activated, to hydrolyze ATP. These changes cannot be attributed to smooth muscle dedifferentiation or to reduced contractile protein expression.
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Affiliation(s)
- Mary E Zacour
- Meakins-Christie Laboratories, McGill University, Montreal H3A 2T5, Canada R3T 2N2
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Sodhi CP, Phadke SA, Batlle D, Sahai A. Hypoxia stimulates osteopontin expression and proliferation of cultured vascular smooth muscle cells: potentiation by high glucose. Diabetes 2001; 50:1482-90. [PMID: 11375351 DOI: 10.2337/diabetes.50.6.1482] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We examined the effect of hypoxia on proliferation and osteopontin (OPN) expression in cultured rat aortic vascular smooth muscle (VSM) cells. In addition, we determined whether hypoxia-induced increases in OPN and cell proliferation are altered under hyperglycemic conditions. Quiescent cultures of VSM cells were exposed to hypoxia (3% O(2)) or normoxia (18% O(2)) in a serum-free medium, and cell proliferation as well as the expression of OPN was assessed. Cells exposed to hypoxia for 24 h exhibited a significant increase in [(3)H]thymidine incorporation followed by a significant increase in cell number at 48 h in comparison with respective normoxic controls. Exposure to hypoxia produced significant increases in OPN protein and mRNA expression at 2 h followed by a gradual decline at 6 and 12 h, with subsequent significant increases at 24 h. Neutralizing antibodies to either OPN or its receptor beta3 integrin but not neutralizing antibodies to beta5 integrin prevented the hypoxia-induced increase in [(3)H]thymidine incorporation. Inhibitors of protein kinase C (PKC) and p38 mitogen-activated protein (MAP) kinase also reduced the hypoxia-induced stimulation of proliferation and OPN synthesis. Exposure to high-glucose (HG) (25 mmol/l) medium under normoxic conditions also resulted in significant increases in OPN protein and mRNA levels as well as the proliferation of VSM cells. Under hypoxic conditions, HG further stimulated OPN synthesis and cell proliferation in an additive fashion. In conclusion, hypoxia-induced proliferation of cultured VSM cells is mediated by the stimulation of OPN synthesis involving PKC and p38 MAP kinase. In addition, hypoxia also enhances the effect of HG conditions on both OPN and proliferation of cultured VSM cells, which may have important implications in the development of diabetic atherosclerosis associated with arterial wall hypoxia.
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Affiliation(s)
- C P Sodhi
- Division of Nephrology and Hypertension, Northwestern University Medical School, 303 E. Chicago Ave., Chicago, IL 60611, USA
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Sodhi CP, Phadke SA, Batlle D, Sahai A. Hypoxia and high glucose cause exaggerated mesangial cell growth and collagen synthesis: role of osteopontin. Am J Physiol Renal Physiol 2001; 280:F667-74. [PMID: 11249858 DOI: 10.1152/ajprenal.2001.280.4.f667] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The effect of hypoxia on the proliferation and collagen synthesis of cultured rat mesangial cells was examined under normal-glucose (NG, 5 mM) and high-glucose (HG, 25 mM)-media conditions. In addition, a role for osteopontin (OPN) in mediating these processes was assessed. Quiescent cultures were exposed to hypoxia (3% O(2)) and normoxia (18% O(2)) in a serum-free medium with NG or HG, and cell proliferation, collagen synthesis, and OPN expression were assessed. Cells exposed to hypoxia in NG medium resulted in significant increases in [(3)H]thymidine incorporation, cell number, and [(3)H]proline incorporation, respectively. HG incubations also produced significant stimulation of these parameters under normoxic conditions, which were markedly enhanced in cells exposed to hypoxia in HG medium. In addition, hypoxia and HG stimulated the mRNA levels of type IV collagen, and the combination of hypoxia and HG resulted in additive increases in type IV collagen expression. Hypoxia and HG also stimulated OPN mRNA and protein levels in an additive fashion. A neutralizing antibody to OPN or its beta(3)-integrin receptor significantly blocked the effect of hypoxia and HG on proliferation and collagen synthesis. In conclusion, these results demonstrate for the first time that hypoxia in HG medium produces exaggerated mesangial cell growth and type IV collagen synthesis. In addition, OPN appears to play a role in mediating the accelerated mesangial cell growth and collagen synthesis found in a hyperglycemic and hypoxic environment.
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Affiliation(s)
- C P Sodhi
- Division of Nephrology and Hypertension, Northwestern University Medical School, Chicago, Illinois 60611, USA
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