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Su XT, Reyes JV, Lackey AE, Demirci H, Bachmann S, Maeoka Y, Cornelius RJ, McCormick JA, Yang CL, Jung HJ, Welling PA, Nelson JW, Ellison DH. Enriched Single-Nucleus RNA-Sequencing Reveals Unique Attributes of Distal Convoluted Tubule Cells. J Am Soc Nephrol 2024; 35:426-440. [PMID: 38238903 PMCID: PMC11000721 DOI: 10.1681/asn.0000000000000297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Accepted: 12/17/2023] [Indexed: 01/24/2024] Open
Abstract
SIGNIFICANCE STATEMENT High-resolution single-nucleus RNA-sequencing data indicate a clear separation between primary sites of calcium and magnesium handling within distal convoluted tubule (DCT). Both DCT1 and DCT2 express Slc12a3, but these subsegments serve distinctive functions, with more abundant magnesium-handling genes along DCT1 and more calcium-handling genes along DCT2. The data also provide insight into the plasticity of the distal nephron-collecting duct junction, formed from cells of separate embryonic origins. By focusing/changing gradients of gene expression, the DCT can morph into different physiological cell states on demand. BACKGROUND The distal convoluted tubule (DCT) comprises two subsegments, DCT1 and DCT2, with different functional and molecular characteristics. The functional and molecular distinction between these segments, however, has been controversial. METHODS To understand the heterogeneity within the DCT population with better clarity, we enriched for DCT nuclei by using a mouse line combining "Isolation of Nuclei Tagged in specific Cell Types" and sodium chloride cotransporter-driven inducible Cre recombinase. We sorted the fluorescently labeled DCT nuclei using Fluorescence-Activated Nucleus Sorting and performed single-nucleus transcriptomics. RESULTS Among 25,183 DCT cells, 75% were from DCT1 and 25% were from DCT2. In addition, there was a small population (<1%) enriched in proliferation-related genes, such as Top2a , Cenpp , and Mki67 . Although both DCT1 and DCT2 expressed sodium chloride cotransporter, magnesium transport genes were predominantly expressed along DCT1, whereas calcium, electrogenic sodium, and potassium transport genes were more abundant along DCT2. The transition between these two segments was gradual, with a transitional zone in which DCT1 and DCT2 cells were interspersed. The expression of the homeobox genes by DCT cells suggests that they develop along different trajectories. CONCLUSIONS Transcriptomic analysis of an enriched rare cell population using a genetically targeted approach clarifies the function and classification of distal cells. The DCT segment is short, can be separated into two subsegments that serve distinct functions, and is speculated to derive from different origins during development.
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Affiliation(s)
- Xiao-Tong Su
- Division of Hypertension and Nephrology, School of Medicine, Oregon Health & Science University, Portland, Oregon
| | - Jeremiah V. Reyes
- Division of Hypertension and Nephrology, School of Medicine, Oregon Health & Science University, Portland, Oregon
- Department of Biochemistry and Molecular Biology, College of Medicine, University of the Philippines Manila, Manila, Philippines
| | - Anne E. Lackey
- Division of Hypertension and Nephrology, School of Medicine, Oregon Health & Science University, Portland, Oregon
| | - Hasan Demirci
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Sebastian Bachmann
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Yujiro Maeoka
- Division of Hypertension and Nephrology, School of Medicine, Oregon Health & Science University, Portland, Oregon
| | - Ryan J. Cornelius
- Division of Hypertension and Nephrology, School of Medicine, Oregon Health & Science University, Portland, Oregon
| | - James A. McCormick
- Division of Hypertension and Nephrology, School of Medicine, Oregon Health & Science University, Portland, Oregon
| | - Chao-Ling Yang
- Division of Hypertension and Nephrology, School of Medicine, Oregon Health & Science University, Portland, Oregon
| | - Hyun Jun Jung
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Paul A. Welling
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jonathan W. Nelson
- Division of Hypertension and Nephrology, School of Medicine, Oregon Health & Science University, Portland, Oregon
| | - David H. Ellison
- Division of Hypertension and Nephrology, School of Medicine, Oregon Health & Science University, Portland, Oregon
- Oregon Clinical and Translational Research Institute, Oregon Health & Science University, Portland, Oregon
- Renal Section, VA Portland Healthcare System, Portland, Oregon
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Kung VL, Nelson JW. Machine Learning Illuminates the Extraglomerular Microvasculature. Kidney360 2023; 4:578-579. [PMID: 37229727 PMCID: PMC10371299 DOI: 10.34067/kid.0000000000000111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Affiliation(s)
- Vanderlene L. Kung
- Department of Pathology and Laboratory Medicine, Oregon Health and Science University, Portland, Oregon
| | - Jonathan W. Nelson
- Division of Nephrology and Hypertension, Oregon Health and Science University, Portland, Oregon
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Nelson JW, Ortiz-Melo DI, Mattocks NK, Emathinger JM, Prescott J, Xu K, Griffiths RC, Wakasaki R, Piehowski PD, Hutchens MP, Coffman TM, Gurley SB. Soluble ACE2 Is Filtered into the Urine. Kidney360 2022; 3:2086-2094. [PMID: 36591353 PMCID: PMC9802553 DOI: 10.34067/kid.0001622022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 08/01/2022] [Indexed: 02/01/2023]
Abstract
Background ACE2 is a key enzyme in the renin-angiotensin system (RAS) capable of balancing the RAS by metabolizing angiotensin II (AngII). First described in cardiac tissue, abundance of ACE2 is highest in the kidney, and it is also expressed in several extrarenal tissues. Previously, we reported an association between enhanced susceptibility to hypertension and elevated renal AngII levels in global ACE2-knockout mice. Methods To examine the effect of ACE2 expressed in the kidney, relative to extrarenal expression, on the development of hypertension, we used a kidney crosstransplantation strategy with ACE2-KO and WT mice. In this model, both native kidneys are removed and renal function is provided entirely by the transplanted kidney, such that four experimental groups with restricted ACE2 expression are generated: WT→WT (WT), KO→WT (KidneyKO), WT→KO (SystemicKO), and KO→KO (TotalKO). Additionally, we used nanoscale mass spectrometry-based proteomics to identify ACE2 fragments in early glomerular filtrate of mice. Results Although significant differences in BP were not detected, a major finding of our study is that shed or soluble ACE2 (sACE2) was present in urine of KidneyKO mice that lack renal ACE2 expression. Detection of sACE2 in the urine of KidneyKO mice during AngII-mediated hypertension suggests that sACE2 originating from extrarenal tissues can reach the kidney and be excreted in urine. To confirm glomerular filtration of ACE2, we used micropuncture and nanoscale proteomics to detect peptides derived from ACE2 in the Bowman's space. Conclusions Our findings suggest that both systemic and renal tissues may contribute to sACE2 in urine, identifying the kidney as a major site for ACE2 actions. Moreover, filtration of sACE2 into the lumen of the nephron may contribute to the pathophysiology of kidney diseases characterized by disruption of the glomerular filtration barrier.
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Affiliation(s)
- Jonathan W. Nelson
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University, Portland, Oregon
| | - David I. Ortiz-Melo
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Health Care Centers, Durham, North Carolina
| | - Natalie K. Mattocks
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Health Care Centers, Durham, North Carolina
| | - Jacqueline M. Emathinger
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University, Portland, Oregon
| | - Jessica Prescott
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Health Care Centers, Durham, North Carolina
| | - Katherine Xu
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Health Care Centers, Durham, North Carolina
| | - Robert C. Griffiths
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Health Care Centers, Durham, North Carolina
| | - Rumie Wakasaki
- Anesthesiology and Perioperative Medicine, Oregon Health and Science University, Portland, Oregon
| | - Paul D. Piehowski
- Environmental and Biological Services Division, Pacific Northwest National Laboratory, Richland, Washington
| | - Michael P. Hutchens
- Anesthesiology and Perioperative Medicine, Oregon Health and Science University, Portland, Oregon
| | - Thomas M. Coffman
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Health Care Centers, Durham, North Carolina,Program in Cardiovascular and Metabolic Disorders, Duke–NUS Medical School, Singapore
| | - Susan B. Gurley
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University, Portland, Oregon,Division of Nephrology, Department of Medicine, Duke University and Durham VA Health Care Centers, Durham, North Carolina
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Cornelius RJ, Nelson JW, Su XT, Yang CL, Ellison DH. COP9 signalosome deletion promotes renal injury and distal convoluted tubule remodeling. Am J Physiol Renal Physiol 2022; 323:F4-F19. [PMID: 35532068 PMCID: PMC9236871 DOI: 10.1152/ajprenal.00436.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Cullin-RING ligases are a family of E3 ubiquitin ligases that control cellular processes through regulated degradation. Cullin 3 targets with-no-lysine kinase 4 (WNK4), a kinase that activates the Na+-Cl- cotransporter (NCC), the main pathway for Na+ reabsorption in the distal convoluted tubule (DCT). Mutations in the cullin 3 gene lead to familial hyperkalemic hypertension by increasing WNK4 abundance. The constitutive photomorphogenesis 9 (COP9) signalosome (CSN) regulates the activity of cullin-RING ligases by removing the ubiquitin-like protein neural precursor cell expressed developmentally downregulated protein 8. Genetic deletion of the catalytically active CSN subunit, Jab1, along the nephron in mice (KS-Jab1-/-) led to increased WNK4 abundance; however, NCC abundance was substantially reduced. We hypothesized that the reduction in NCC resulted from a cortical injury that led to hypoplasia of the segment, which counteracted WNK4 activation of NCC. To test this, we studied KS-Jab1-/- mice at weekly intervals over a period of 3 wk. The results showed that NCC abundance was unchanged until 3 wk after Jab1 deletion, at which time other DCT-specific proteins were also reduced. The kidney injury markers kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin demonstrated kidney injury immediately after Jab1 deletion; however, the damage was initially limited to the medulla. The injury progressed and expanded into the cortex 3 wk after Jab1 deletion coinciding with loss of the DCT. The data indicate that nephron-specific disruption of the cullin-RING ligase system results in a complex progression of tubule injury that leads to hypoplasia of the DCT.NEW & NOTEWORTHY Cullin 3 (CUL3) targets with-no-lysine-kinase 4 (WNK4), which activates Na+-Cl- cotransporter (NCC) in the distal convoluted tubule (DCT) of the kidney. Renal-specific genetic deletion of the constitutive photomorphogenesis 9 signalosome, an upstream regulator of CUL3, resulted in a reduction of NCC due to DCT hypoplasia, which coincided with cortical kidney injury. The data indicate that nephron-specific disruption of the cullin-RING ligase system results in a complex progression of tubule injury leading to hypoplasia of the DCT.
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Affiliation(s)
- Ryan J. Cornelius
- 1Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Jonathan W. Nelson
- 1Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Xiao-Tong Su
- 1Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Chao-Ling Yang
- 1Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - David H. Ellison
- 1Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon,2Veterans Affairs Portland Health Care System, Portland, Oregon
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5
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Alkayed NJ, Cao Z, Qian ZY, Nagarajan S, Liu X, Nelson JW, Xie F, Li B, Fan W, Liu L, Grafe MR, Davis CM, Xiao X, Barnes AP, Kaul S. Control of Coronary Vascular Resistance by Eicosanoids via a Novel GPCR. Am J Physiol Cell Physiol 2022; 322:C1011-C1021. [PMID: 35385329 PMCID: PMC9255704 DOI: 10.1152/ajpcell.00454.2021] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Arachidonic acid metabolites epoxyeicosatrienoates (EETs) and hydroxyeicosatetraenoates (HETEs) are important regulators of myocardial blood flow and coronary vascular resistance (CVR), but their mechanisms of action are not fully understood. We applied a chemoproteomics strategy using a clickable photoaffinity probe to identify G protein coupled receptor 39 (GPR39) as a microvascular smooth muscle cell (mVSMC) receptor selective for two endogenous eicosanoids, 15-HETE and 14,15-EET, which act on the receptor to oppose each other's activity. The former increases mVSMC intracellular calcium via GPR39 and augments coronary microvascular resistance, and the latter inhibits these actions. Furthermore, we find that the efficacy of both ligands is potentiated by zinc acting as an allosteric modulator. Measurements of coronary perfusion pressure (CPP) in GPR39-null hearts using the Langendorff preparation indicate the receptor senses these eicosanoids to regulate microvascular tone. These results implicate GPR39 as an eicosanoid receptor and key regulator of myocardial tissue perfusion. Our findings will have a major impact on understanding the roles of eicosanoids in cardiovascular physiology and disease and provide an opportunity for the development of novel GPR39-targeting therapies for cardiovascular disease.
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Affiliation(s)
- Nabil J Alkayed
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, United States.,The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Zhiping Cao
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, United States.,The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Zu Yuan Qian
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, United States.,The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Shanthi Nagarajan
- The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, United States.,Medicinal Chemistry Core, Oregon Health & Science University, Portland, Oregon, United States
| | - Xuehong Liu
- The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Jonathan W Nelson
- The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Fuchun Xie
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon, United States
| | - Bingbing Li
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon, United States
| | - Wei Fan
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, United States.,The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Lijuan Liu
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, United States.,The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Marjorie R Grafe
- DDepartment of Pathology, Oregon Health & Science University, Portland, Oregon, United States
| | - Catherine M Davis
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, United States.,The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Xiangshu Xiao
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon, United States.,The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Anthony P Barnes
- The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Sanjiv Kaul
- The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, United States
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6
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Davis CM, Bah TM, Zhang WH, Nelson JW, Golgotiu K, Nie X, Alkayed FN, Young JM, Woltjer RL, Silbert LC, Grafe MR, Alkayed NJ. GPR39 localization in the aging human brain and correlation of expression and polymorphism with vascular cognitive impairment. Alzheimers Dement (N Y) 2021; 7:e12214. [PMID: 34692987 PMCID: PMC8515554 DOI: 10.1002/trc2.12214] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 06/24/2021] [Accepted: 08/11/2021] [Indexed: 12/30/2022]
Abstract
INTRODUCTION The pathogenesis of vascular cognitive impairment (VCI) is not fully understood. GPR39, an orphan G-protein coupled receptor, is implicated in neurological disorders but its role in VCI is unknown. METHODS We performed GPR39 immunohistochemical analysis in post mortem brain samples from mild cognitive impairment (MCI) and control subjects. DNA was analyzed for GPR39 single nucleotide polymorphisms (SNPs), and correlated with white matter hyperintensity (WMH) burden on pre mortem magnetic resonance imaging. RESULTS GPR39 is expressed in aged human dorsolateral prefrontal cortex, localized to microglia and peri-capillary cells resembling pericytes. GPR39-capillary colocalization, and density of GPR39-expressing microglia was increased in aged brains compared to young. SNP distribution was equivalent between groups; however, homozygous SNP carriers were present only in the MCI group, and had higher WMH volume than wild-type or heterozygous SNP carriers. DISCUSSION GPR39 may play a role in aging-related VCI, and may serve as a therapeutic target and biomarker for the risk of developing VCI.
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Affiliation(s)
- Catherine M. Davis
- Department of Anesthesiology & Perioperative MedicineOregon Health & Science UniversityPortlandOregonUSA
| | - Thierno M. Bah
- Department of Anesthesiology & Perioperative MedicineOregon Health & Science UniversityPortlandOregonUSA
| | - Wenri H. Zhang
- Department of Anesthesiology & Perioperative MedicineOregon Health & Science UniversityPortlandOregonUSA
| | - Jonathan W. Nelson
- Division of Nephrology and Hypertension, Department of MedicineOregon Health & Science UniversityPortlandOregonUSA
| | - Kirsti Golgotiu
- Department of Anesthesiology & Perioperative MedicineOregon Health & Science UniversityPortlandOregonUSA
| | - Xiao Nie
- Department of Anesthesiology & Perioperative MedicineOregon Health & Science UniversityPortlandOregonUSA
| | - Farah N. Alkayed
- Department of Anesthesiology & Perioperative MedicineOregon Health & Science UniversityPortlandOregonUSA
| | - Jennifer M. Young
- Department of Anesthesiology & Perioperative MedicineOregon Health & Science UniversityPortlandOregonUSA
- Knight Cardiovascular Institute, Oregon Health & Science UniversityPortlandOregonUSA
| | - Randy L. Woltjer
- Department of PathologyOregon Health & Science UniversityPortlandOregonUSA
| | - Lisa C. Silbert
- Layton Aging and Alzheimer's Disease Research CenterDepartment of NeurologyOregon Health & Science UniversityPortlandOregonUSA
| | - Marjorie R. Grafe
- Department of Anesthesiology & Perioperative MedicineOregon Health & Science UniversityPortlandOregonUSA
- Department of PathologyOregon Health & Science UniversityPortlandOregonUSA
| | - Nabil J. Alkayed
- Department of Anesthesiology & Perioperative MedicineOregon Health & Science UniversityPortlandOregonUSA
- Knight Cardiovascular Institute, Oregon Health & Science UniversityPortlandOregonUSA
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7
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Emechebe U, Nelson JW, Alkayed NJ, Kaul S, Adey AC, Barnes AP. Age-dependent transcriptional alterations in cardiac endothelial cells. Physiol Genomics 2021; 53:295-308. [PMID: 34097533 PMCID: PMC8321782 DOI: 10.1152/physiolgenomics.00037.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/14/2021] [Accepted: 05/14/2021] [Indexed: 02/08/2023] Open
Abstract
Aging is a significant risk factor for cardiovascular disease. Despite the fact that endothelial cells play critical roles in cardiovascular function and disease, the molecular impact of aging on this cell population in many organ systems remains unknown. In this study, we sought to determine age-associated transcriptional alterations in cardiac endothelial cells. Highly enriched populations of endothelial cells (ECs) isolated from the heart, brain, and kidney of young (3 mo) and aged (24 mo) C57/BL6 mice were profiled for RNA expression via bulk RNA sequencing. Approximately 700 cardiac endothelial transcripts significantly differ by age. Gene set enrichment analysis indicated similar patterns for cellular pathway perturbations. Receptor-ligand comparisons indicated parallel alterations in age-affected circulating factors and cardiac endothelial-expressed receptors. Gene and pathway enrichment analyses show that age-related transcriptional response of cardiac endothelial cells is distinct from that of endothelial cells derived from the brain or kidney vascular bed. Furthermore, single-cell analysis identified nine distinct EC subtypes and shows that the Apelin Receptor-enriched subtype is reduced with age in mouse heart. Finally, we identify age-dysregulated genes in specific aged cardiac endothelial subtypes.
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Affiliation(s)
- Uchenna Emechebe
- The Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon
| | - Jonathan W Nelson
- The Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon
| | - Nabil J Alkayed
- The Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon
- Department of Anesthesiology and Perioperative Medicine, Oregon Health and Science University, Portland, Oregon
| | - Sanjiv Kaul
- The Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon
| | - Andrew C Adey
- The Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon
- Knight Cancer Institute, Oregon Health and Science University, Portland, Oregon
- Cancer Early Detection Advanced Research Institute, Oregon Health and Science University, Portland, Oregon
| | - Anthony P Barnes
- The Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon
- Department of Anesthesiology and Perioperative Medicine, Oregon Health and Science University, Portland, Oregon
- Department of Cell, Developmental and Cancer Biology, Oregon Health and Science University, Portland, Oregon
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8
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Emathinger JM, Nelson JW, Gurley SB. Advances in use of mouse models to study the renin-angiotensin system. Mol Cell Endocrinol 2021; 529:111255. [PMID: 33789143 PMCID: PMC9119406 DOI: 10.1016/j.mce.2021.111255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 01/19/2021] [Accepted: 03/20/2021] [Indexed: 12/28/2022]
Abstract
The renin-angiotensin system (RAS) is a highly complex hormonal cascade that spans multiple organs and cell types to regulate solute and fluid balance along with cardiovascular function. Much of our current understanding of the functions of the RAS has emerged from a series of key studies in genetically-modified animals. Here, we review key findings from ground-breaking transgenic models, spanning decades of research into the RAS, with a focus on their use in studying blood pressure. We review the physiological importance of this regulatory system as evident through the examination of mouse models for several major RAS components: angiotensinogen, renin, ACE, ACE2, and the type 1 A angiotensin receptor. Both whole-animal and cell-specific knockout models have permitted critical RAS functions to be defined and demonstrate how redundancy and multiplicity within the RAS allow for compensatory adjustments to maintain homeostasis. Moreover, these models present exciting opportunities for continued discovery surrounding the role of the RAS in disease pathogenesis and treatment for cardiovascular disease and beyond.
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MESH Headings
- Angiotensin-Converting Enzyme 2/deficiency
- Angiotensin-Converting Enzyme 2/genetics
- Angiotensinogen/deficiency
- Angiotensinogen/genetics
- Animals
- Blood Pressure/genetics
- Cardiovascular Diseases/genetics
- Cardiovascular Diseases/metabolism
- Cardiovascular Diseases/pathology
- Disease Models, Animal
- Gene Expression Regulation
- Humans
- Kidney/cytology
- Kidney/metabolism
- Mice
- Mice, Knockout
- Receptor, Angiotensin, Type 1/deficiency
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 2/deficiency
- Receptor, Angiotensin, Type 2/genetics
- Renin/deficiency
- Renin/genetics
- Renin-Angiotensin System/genetics
- Signal Transduction
- Water-Electrolyte Balance/genetics
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Affiliation(s)
- Jacqueline M Emathinger
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, OR, USA.
| | - Jonathan W Nelson
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, OR, USA.
| | - Susan B Gurley
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, OR, USA.
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Nelson JW, McDonough AA, Xiang Z, Ralph DL, Robertson JA, Giani JF, Bernstein KE, Gurley SB. Local and downstream actions of proximal tubule angiotensin II signaling on Na + transporters in the mouse nephron. Am J Physiol Renal Physiol 2021; 321:F69-F81. [PMID: 34056928 DOI: 10.1152/ajprenal.00014.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The renal nephron consists of a series of distinct cell types that function in concert to maintain fluid and electrolyte balance and blood pressure. The renin-angiotensin system (RAS) is central to Na+ and volume balance. We aimed to determine how loss of angiotensin II signaling in the proximal tubule (PT), which reabsorbs the bulk of filtered Na+ and volume, impacts solute transport throughout the nephron. We hypothesized that PT renin-angiotensin system disruption would not only depress PT Na+ transporters but also impact downstream Na+ transporters. Using a mouse model in which the angiotensin type 1a receptor (AT1aR) is deleted specifically within the PT (AT1aR PTKO), we profiled the abundance of Na+ transporters, channels, and claudins along the nephron. Absence of PT AT1aR signaling was associated with lower abundance of PT transporters (Na+/H+ exchanger isoform 3, electrogenic Na+-bicarbonate cotransporter 1, and claudin 2) as well as lower abundance of downstream transporters (total and phosphorylated Na+-K+-2Cl- cotransporter, medullary Na+-K+-ATPase, phosphorylated NaCl cotransporter, and claudin 7) versus controls. However, transport activities of Na+-K+-2Cl- cotransporter and NaCl cotransporter (assessed with diuretics) were similar between groups in order to maintain electrolyte balance. Together, these results demonstrate the primary impact of angiotensin II regulation on Na+ reabsorption in the PT at baseline and the associated influence on downstream Na+ transporters, highlighting the ability of the nephron to integrate Na+ transport along the nephron to maintain homeostasis.NEW & NOTEWORTHY Our study defines a novel role for proximal tubule angiotensin receptors in regulating the abundance of Na+ transporters throughout the nephron, thereby contributing to the integrated control of fluid balance in vivo.
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Affiliation(s)
- Jonathan W Nelson
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Alicia A McDonough
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Zhidan Xiang
- Wake Forest University, Winston-Salem, North Carolina
| | - Donna L Ralph
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Joshua A Robertson
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Jorge F Giani
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
| | - Kenneth E Bernstein
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
| | - Susan B Gurley
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
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10
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Ferdaus MZ, Mukherjee A, Nelson JW, Blatt PJ, Miller LN, Terker AS, Staub O, Lin DH, McCormick JA. Mg 2+ restriction downregulates NCC through NEDD4-2 and prevents its activation by hypokalemia. Am J Physiol Renal Physiol 2019; 317:F825-F838. [PMID: 31364380 PMCID: PMC6843039 DOI: 10.1152/ajprenal.00216.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Hypomagnesemia is associated with reduced kidney function and life-threatening complications and sustains hypokalemia. The distal convoluted tubule (DCT) determines final urinary Mg2+ excretion and, via activity of the Na+-Cl- cotransporter (NCC), also plays a key role in K+ homeostasis by metering Na+ delivery to distal segments. Little is known about the mechanisms by which plasma Mg2+ concentration regulates NCC activity and how low-plasma Mg2+ concentration and K+ concentration interact to modulate NCC activity. To address this, we performed dietary manipulation studies in mice. Compared with normal diet, abundances of total NCC and phosphorylated NCC (pNCC) were lower after short-term (3 days) or long-term (14 days) dietary Mg2+ restriction. Altered NCC activation is unlikely to play a role, since we also observed lower total NCC abundance in mice lacking the two NCC-activating kinases, STE20/SPS-1-related proline/alanine-rich kinase and oxidative stress response kinase-1, after Mg2+ restriction. The E3 ubiquitin-protein ligase NEDD4-2 regulates NCC abundance during dietary NaCl loading or K+ restriction. Mg2+ restriction did not lower total NCC abundance in inducible nephron-specific neuronal precursor cell developmentally downregulated 4-2 (NEDD4-2) knockout mice. Total NCC and pNCC abundances were similar after short-term Mg2+ or combined Mg2+-K+ restriction but were dramatically lower compared with a low-K+ diet. Therefore, sustained NCC downregulation may serve a mechanism that enhances distal Na+ delivery during states of hypomagnesemia, maintaining hypokalemia. Similar results were obtained with long-term Mg2+-K+ restriction, but, surprisingly, NCC was not activated after long-term K+ restriction despite lower plasma K+ concentration, suggesting significant differences in distal tubule adaptation to acute or chronic K+ restriction.
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Affiliation(s)
- Mohammed Z. Ferdaus
- 1Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Anindit Mukherjee
- 1Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Jonathan W. Nelson
- 1Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Philip J. Blatt
- 1Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Lauren N. Miller
- 1Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Andrew S. Terker
- 2Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Olivier Staub
- 3Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Dao-Hong Lin
- 4Department of Pharmacology, New York Medical College, Valhalla, New York
| | - James A. McCormick
- 1Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
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11
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Abstract
PURPOSE OF REVIEW Members of the Cullin family act as scaffolds in E3 ubiquitin ligases and play a central role in mediating protein degradation. Interactions with many different substrate-binding adaptors permit Cullin-containing E3 ligases to participate in diverse cellular functions. In the kidney, one well established target of Cullin-mediated degradation is the transcription factor Nrf2, a key player in responses to oxidative stress. The goal of this review is to discuss more recent findings revealing broader roles for Cullins in the kidney. RECENT FINDINGS Cullin 3 acts as the scaffold in the E3 ligase regulating Nrf2 abundance, but was more recently shown to be mutated in the disease familial hyperkalemic hypertension. Studies seeking to elucidate the molecular mechanisms by which Cullin 3 mutations lead to dysregulation of renal sodium transport will be discussed. Disruption of Cullin 3 in mice unexpectedly causes polyuria and fibrotic injury suggesting it has additional roles in the kidney. We will also review recent transcriptomic data suggesting that other Cullins are also likely to play important roles in renal function. SUMMARY Cullins form a large and diverse family of E3 ubiquitin ligases that are likely to have many important functions in the kidney.
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Affiliation(s)
- Ryan J. Cornelius
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University, Portland, OR
| | - Mohammed Z. Ferdaus
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University, Portland, OR
| | - Jonathan W. Nelson
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University, Portland, OR
| | - James A. McCormick
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University, Portland, OR
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12
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Chen L, Clark JZ, Nelson JW, Kaissling B, Ellison DH, Knepper MA. Renal-Tubule Epithelial Cell Nomenclature for Single-Cell RNA-Sequencing Studies. J Am Soc Nephrol 2019; 30:1358-1364. [PMID: 31253652 DOI: 10.1681/asn.2019040415] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Affiliation(s)
- Lihe Chen
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Jevin Z Clark
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Jonathan W Nelson
- Division of Nephrology and Hypertension, Oregon Health & Science University, Portland, Oregon; and
| | | | - David H Ellison
- Division of Nephrology and Hypertension, Oregon Health & Science University, Portland, Oregon; and
| | - Mark A Knepper
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland;
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13
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Cornelius RJ, Nelson JW, Su X, Yang C, Ellison DH. Long‐term Disruption of the COP9 Signalosome Decreases NCC Abundance Due to Remodeling of the DCT. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.862.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | - David H. Ellison
- Oregon Health and Science UniversityPortlandOR
- VA Portland Healthcare SystemPortlandOR
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14
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Swanson EA, Nelson JW, Jeng S, Erspamer KJ, Yang CL, McWeeney S, Ellison DH. Salt-sensitive transcriptome of isolated kidney distal tubule cells. Physiol Genomics 2019; 51:125-135. [PMID: 30875275 DOI: 10.1152/physiolgenomics.00119.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In the distal kidney tubule, the steroid hormone aldosterone regulates sodium reabsorption via the epithelial sodium channel (ENaC). Most studies seeking to identify ENaC-regulating aldosterone-induced proteins have used transcriptional profiling of cultured cells. To identify salt-sensitive transcripts in an in vivo model, we used low-NaCl or high-NaCl diet to stimulate or suppress endogenous aldosterone, in combination with magnetic- and fluorescence-activated cell sorting to isolate distal tubule cells from mouse kidney for transcriptional profiling. Of the differentially expressed transcripts, 162 were more abundant in distal tubule cells isolated from mice fed low-NaCl diet, and 161 were more abundant in distal tubule cells isolated from mice fed high-NaCl diet. Enrichment analysis of Gene Ontology biological process terms identified multiple statistically overrepresented pathways among the differentially expressed transcripts that were more abundant in distal tubule cells isolated from mice fed low-NaCl diet, including ion transmembrane transport, regulation of growth, and negative regulation of apoptosis. Analysis of Gene Ontology molecular function terms identified differentially expressed transcription factors, transmembrane transporters, kinases, and G protein-coupled receptors. Finally, comparison with a recently published study of gene expression changes in distal tubule cells in response to administration of aldosterone identified 18 differentially expressed genes in common between the two experiments. When expression of these genes was measured in cortical collecting ducts microdissected from mice fed low-NaCl or high-NaCl diet, eight were differentially expressed. These genes are likely to be regulated directly by aldosterone and may provide insight into aldosterone signaling to ENaC in the distal tubule.
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Affiliation(s)
- Elizabeth A Swanson
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health & Science University , Portland, Oregon
| | - Jonathan W Nelson
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health & Science University , Portland, Oregon
| | - Sophia Jeng
- Division of Bioinformatics & Computational Biology, Department of Medical Informatics and Clinical Epidemiology, Oregon Health & Science University , Portland, Oregon
| | - Kayla J Erspamer
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health & Science University , Portland, Oregon
| | - Chao-Ling Yang
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health & Science University , Portland, Oregon
| | - Shannon McWeeney
- Division of Bioinformatics & Computational Biology, Department of Medical Informatics and Clinical Epidemiology, Oregon Health & Science University , Portland, Oregon.,Oregon Clinical & Translational Research Institute, Oregon Health & Science University , Portland, Oregon
| | - David H Ellison
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health & Science University , Portland, Oregon.,Oregon Clinical & Translational Research Institute, Oregon Health & Science University , Portland, Oregon.,Renal Section, Portland VA Medical Center , Portland, Oregon
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15
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Cornelius RJ, Si J, Cuevas CA, Nelson JW, Gratreak BDK, Pardi R, Yang CL, Ellison DH. Renal COP9 Signalosome Deficiency Alters CUL3-KLHL3-WNK Signaling Pathway. J Am Soc Nephrol 2018; 29:2627-2640. [PMID: 30301860 DOI: 10.1681/asn.2018030333] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 09/07/2018] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND The familial hyperkalemic hypertension (FHHt) cullin 3 (CUL3) mutant does not degrade WNK kinases normally, thereby leading to thiazide-sensitive Na-Cl cotransporter (NCC) activation. CUL3 mutant (CUL3Δ9) does not bind normally to the COP9 signalosome (CSN), a deneddylase involved in regulating cullin-RING ligases. CUL3Δ9 also caused increased degradation of the CUL3-WNK substrate adaptor kelch-like 3 (KLHL3). Here, we sought to determine how defective CSN action contributes to the CUL3Δ9 phenotype. METHODS The Pax8/LC1 mouse system was used to generate mice in which the catalytically active CSN subunit, Jab1, was deleted only along the nephron, after full development (KS-Jab1 -/-). RESULTS Western blot analysis demonstrated that Jab1 deletion increased the abundance of neddylated CUL3. Moreover, total CUL3 expression was reduced, suggesting decreased CUL3 stability. KLHL3 was almost completely absent in KS-Jab1 -/- mice. Conversely, the protein abundances of WNK1, WNK4, and SPAK kinases were substantially higher. Activation of WNK4, SPAK, and OSR1 was indicated by higher phosphorylated protein levels and translocation of the proteins into puncta, as observed by immunofluorescence. The ratio of phosphorylated NCC to total NCC was also higher. Surprisingly, NCC protein abundance was low, likely contributing to hypokalemia and Na+ and K+ wasting. Additionally, long-term Jab1 deletion resulted in kidney damage. CONCLUSIONS Together, the results indicate that deficient CSN binding contributes importantly to the FHHt phenotype. Although defective CUL3Δ9-faciliated WNK4 degradation likely contributes, dominant effects on KLHL3 may be a second factor that is necessary for the phenotype.
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Affiliation(s)
- Ryan J Cornelius
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Jinge Si
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Catherina A Cuevas
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Jonathan W Nelson
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Brittany D K Gratreak
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Ruggero Pardi
- School of Medicine and Scientific Institute, San Raffaele University, Milan, Italy; and
| | - Chao-Ling Yang
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - David H Ellison
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon; .,Renal Section, Veterans Affairs Portland Health Care System, Portland, Oregon
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16
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Nelson JW, Sklenar J, Barnes AP, Minnier J. The START App: a web-based RNAseq analysis and visualization resource. Bioinformatics 2018; 33:447-449. [PMID: 28171615 DOI: 10.1093/bioinformatics/btw624] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 09/09/2016] [Accepted: 09/23/2016] [Indexed: 11/14/2022] Open
Abstract
Summary Transcriptional profiling using RNA sequencing (RNAseq) has emerged as a powerful methodology to quantify global gene expression patterns in various contexts from single cells to whole tissues. The tremendous amount of data generated by this profiling technology presents a daunting challenge in terms of effectively visualizing and interpreting results. Convenient and intuitive data interfaces are critical for researchers to easily upload, analyze and visualize their RNAseq data. We designed the START (Shiny Transcriptome Analysis Resource Tool) App with these requirements in mind. This application has the power and flexibility to be resident on a local computer or serve as a web-based environment, enabling easy sharing of data between researchers and collaborators. Availability and Implementation Source Code for the START App is written entirely in R and can be freely available to download at https://github.com/jminnier/STARTapp with the code licensed under GPLv3. It can be launched on any system that has R installed. The START App is also hosted on https://kcvi.shinyapps.io/START for researchers to temporarily upload their data. Contact minnier@ohsu.edu
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Affiliation(s)
- Jonathan W Nelson
- The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA
| | - Jiri Sklenar
- The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA
| | - Anthony P Barnes
- Department of Pediatrics, Oregon Health & Science University, Portland, OR, USA
| | - Jessica Minnier
- The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA.,School of Public Health, Oregon Health & Science University, Portland, OR, USA
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17
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Davis L, Musso J, Soman D, Louey S, Nelson JW, Jonker SS. Role of adenosine signaling in coordinating cardiomyocyte function and coronary vascular growth in chronic fetal anemia. Am J Physiol Regul Integr Comp Physiol 2018; 315:R500-R508. [PMID: 29791204 DOI: 10.1152/ajpregu.00319.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fetal anemia causes rapid and profound changes in cardiac structure and function, stimulating proliferation of the cardiac myocytes, expansion of the coronary vascular tree, and impairing early contraction and relaxation. Although hypoxia-inducible factor-1α is sure to play a role, adenosine, a metabolic byproduct that increases coronary flow and growth, is implicated as a major stimulus for these adaptations. We hypothesized that genes involved in myocardial adenosine signaling would be upregulated in chronically anemic fetuses and that calcium-handling genes would be downregulated. After sterile surgical instrumentation under anesthesia, gestationally timed fetal sheep were made anemic by isovolumetric hemorrhage for 1 wk (16% vs. 35% hematocrit). At 87% of gestation, necropsy was performed to collect heart tissue for PCR and immunohistochemical analysis. Anemia increased mRNA expression levels of adenosine receptors ADORA 1, ADORA2A, and ADORA2B in the left and right ventricles (adenosine receptor ADORA3 was unchanged). In both ventricles, anemia also increased expression of ectonucleoside triphosphate diphosphohydrolase 1 and ecto-5'-nucleotidase. The genes for both equilibrative nucleoside transporters 1 and 2 were expressed more abundantly in the anemic right ventricle but were not different in the left ventricle. Neither adenosine deaminase nor adenosine kinase cardiac levels were significantly changed by chronic fetal anemia. Chronic fetal anemia did not significantly change cardiac mRNA expression levels of the voltage-dependent L-type calcium channel, ryanodine receptor 1, sodium-calcium exchanger, sarcoplasmic/endoplasmic reticulum calcium transporting ATPase 2, phospholamban, or cardiac calsequestrin. These data support local metabolic integration of vascular and myocyte function through adenosine signaling in the anemic fetal heart.
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Affiliation(s)
- Lowell Davis
- Center for Developmental Health, Oregon Health & Science University , Portland, Oregon.,Department of Obstetrics and Gynecology, Oregon Health & Science University , Portland, Oregon
| | - James Musso
- Center for Developmental Health, Oregon Health & Science University , Portland, Oregon
| | - Divya Soman
- Center for Developmental Health, Oregon Health & Science University , Portland, Oregon.,Knight Cardiovascular Institute, Oregon Health & Science University , Portland, Oregon
| | - Samantha Louey
- Center for Developmental Health, Oregon Health & Science University , Portland, Oregon.,Knight Cardiovascular Institute, Oregon Health & Science University , Portland, Oregon
| | - Jonathan W Nelson
- Knight Cardiovascular Institute, Oregon Health & Science University , Portland, Oregon
| | - Sonnet S Jonker
- Center for Developmental Health, Oregon Health & Science University , Portland, Oregon.,Knight Cardiovascular Institute, Oregon Health & Science University , Portland, Oregon
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18
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Swanson EA, Nelson JW, Jeng S, Erspamer KJ, Yang C, McWeeney S, Ellison DH. Aldosterone‐Induced Transcripts Identified from Rapidly Isolated Collecting Duct Cells. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.850.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Elizabeth A. Swanson
- Division of Nephrology & HypertensionOregon Health & Science UniversityPortlandOR
| | - Jonathan W. Nelson
- Knight Cardiovascular InstituteOregon Health & Science UniversityPortlandOR
| | - Sophia Jeng
- Oregon Clinical & Translational Research InstituteOregon Health & Science UniversityPortlandOR
| | - Kayla J. Erspamer
- Division of Nephrology & HypertensionOregon Health & Science UniversityPortlandOR
| | - Chao‐Ling Yang
- Division of Nephrology & HypertensionOregon Health & Science UniversityPortlandOR
| | - Shannon McWeeney
- Division of Bioinformatics & Computational BiologyOregon Health & Science UniversityPortlandOR
- Oregon Clinical & Translational Research InstituteOregon Health & Science UniversityPortlandOR
| | - David H. Ellison
- Renal SectionPortland VA Medical CenterPortlandOR
- Division of Nephrology & HypertensionOregon Health & Science UniversityPortlandOR
- Oregon Clinical & Translational Research InstituteOregon Health & Science UniversityPortlandOR
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19
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Nelson JW, Ferdaus MZ, McCormick JA, Minnier J, Kaul S, Ellison DH, Barnes AP. Endothelial transcriptomics reveals activation of fibrosis-related pathways in hypertension. Physiol Genomics 2018; 50:104-116. [PMID: 29212850 DOI: 10.1152/physiolgenomics.00111.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Hypertension poses a significant challenge to vasculature homeostasis and stands as the most common cardiovascular disease in the world. Its effects are especially profound on endothelial cells that form the inner lining of the vasculature and are directly exposed to the effects of excess pressure. Here, we characterize the in vivo transcriptomic response of cardiac endothelial cells to hypertension by rapidly isolating these cells from the spontaneous hypertension mouse model BPH/2J and its normotensive BPN/3J control strain and performing and RNA sequencing on both. Comparison of transcriptional differences between these groups reveals statistically significant changes in cellular pathways consistent with cardiac fibrosis found in hypertensive animals. Importantly, many of the fibrosis-linked genes identified also differ significantly between juvenile prehypertensive and adult hypertensive BPH/2J mice, suggesting that these transcriptional differences are hypertension related. We examined the dynamic nature of these transcriptional changes by testing whether blood pressure normalization using either a calcium channel blocker (amlodipine) or a angiotensin II receptor blocker (losartan) is able to reverse these expression patterns associated with hypertension. We find that blood pressure reduction is capable of reversing some gene-expression patterns, while other transcripts are recalcitrant to therapeutic intervention. This illuminates the possibility that unmanaged hypertension may irreversibly alter some endothelial transcriptional patterns despite later intervention. This study quantifies how endothelial cells are remodeled at the molecular level in cardiovascular pathology and advances our understanding of the transcriptional events associated with endothelial response to hypertensive challenge.
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Affiliation(s)
- Jonathan W Nelson
- The Knight Cardiovascular Institute, Oregon Health & Science University , Portland, Oregon
| | - Mohammed Z Ferdaus
- Division of Nephrology and Hypertension, Oregon Health & Science University, Portland, Oregon
| | - James A McCormick
- Division of Nephrology and Hypertension, Oregon Health & Science University, Portland, Oregon
| | - Jessica Minnier
- The Knight Cardiovascular Institute, Oregon Health & Science University , Portland, Oregon
| | - Sanjiv Kaul
- The Knight Cardiovascular Institute, Oregon Health & Science University , Portland, Oregon
| | - David H Ellison
- Division of Nephrology and Hypertension, Oregon Health & Science University, Portland, Oregon.,Department of Medicine, Oregon Clinical and Translational Research Institute, Oregon Health & Science University , Portland, Oregon
| | - Anthony P Barnes
- The Knight Cardiovascular Institute, Oregon Health & Science University , Portland, Oregon
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20
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Liu X, Qian ZY, Xie F, Fan W, Nelson JW, Xiao X, Kaul S, Barnes AP, Alkayed NJ. Functional screening for G protein-coupled receptor targets of 14,15-epoxyeicosatrienoic acid. Prostaglandins Other Lipid Mediat 2016; 132:31-40. [PMID: 27649858 DOI: 10.1016/j.prostaglandins.2016.09.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 09/07/2016] [Accepted: 09/13/2016] [Indexed: 01/01/2023]
Abstract
Epoxyeicosatrienoic acids (EETs) are potent vasodilators that play important roles in cardiovascular physiology and disease, yet the molecular mechanisms underlying the biological actions of EETs are not fully understood. Multiple lines of evidence suggest that the actions of EETs are in part mediated via G protein-coupled receptor (GPCR) signaling, but the identity of such a receptor has remained elusive. We sought to identify 14,15-EET-responsive GPCRs. A set of 105 clones were expressed in Xenopus oocyte and screened for their ability to activate cAMP-dependent chloride current. Several receptors responded to micromolar concentrations of 14,15-EET, with the top five being prostaglandin receptor subtypes (PTGER2, PTGER4, PTGFR, PTGDR, PTGER3IV). Overall, our results indicate that multiple low-affinity 14,15-EET GPCRs are capable of increasing cAMP levels following 14,15-EET stimulation, highlighting the potential for cross-talk between prostanoid and other ecosanoid GPCRs. Our data also indicate that none of the 105 GPCRs screened met our criteria for a high-affinity receptor for 14,15-EET.
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Affiliation(s)
- Xuehong Liu
- The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States
| | - Zu-Yuan Qian
- The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States
| | - Fuchun Xie
- Departments of Physiology & Pharmacology, Oregon Health & Science University, Portland, OR, United States
| | - Wei Fan
- The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States
| | - Jonathan W Nelson
- The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States
| | - Xiangshu Xiao
- Departments of Physiology & Pharmacology, Oregon Health & Science University, Portland, OR, United States; The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States
| | - Sanjiv Kaul
- The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States
| | - Anthony P Barnes
- Departments of Pediatrics, Oregon Health & Science University, Portland, OR, United States; The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States.
| | - Nabil J Alkayed
- Departments of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, United States; Departments of Physiology & Pharmacology, Oregon Health & Science University, Portland, OR, United States; The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States.
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21
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Abstract
The epoxyeicosatrienoic acid (EET) neutralizing enzyme soluble epoxide hydrolase (sEH) is a neuronal enzyme, which has been localized in both the cytosol and peroxisomes. The molecular basis for its dual localization remains unclear as sEH contains a functional peroxisomal targeting sequence (PTS). Recently, a missense polymorphism was identified in human sEH (R287Q) that enhances its peroxisomal localization. This same polymorphism has also been shown to generate weaker sEH homo-dimers. Taken together, these observations suggest that dimerization may mask the sEH PTS and prevent peroxisome translocation. In the current study, we test the hypothesis that dimerization is a key regulator of sEH subcellular localization. Specifically, we altered the dimerization state of sEH by introducing substitutions in amino acids responsible for the dimer-stabilizing salt-bridge. Green Fluorescent Protein (GFP) fusions of each of mutants were co-transfected into mouse primary cultured cortical neurons together with a PTS-linked red fluorescent protein to constitutively label peroxisomes. Labeled neurons were analyzed using confocal microscopy and co-localization of sEH with peroxisomes was quantified using Pearson's correlation coefficient. We find that dimer-competent sEH constructs preferentially localize to the cytosol, whereas constructs with weakened or disrupted dimerization were preferentially targeted to peroxisomes. We conclude that the sEH dimerization status is a key regulator of its peroxisomal localization.
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Affiliation(s)
- Jonathan W. Nelson
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, 97239–3098, United States of America
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, 97239–3098, United States of America
- The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, 97239–3098, United States of America
| | - Anjali J. Das
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, 97239–3098, United States of America
| | - Anthony P. Barnes
- The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, 97239–3098, United States of America
- Pape Family Research Center, Department of Pediatrics Oregon Health & Science University, Portland, OR, 97239–3098, United States of America
| | - Nabil J. Alkayed
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, 97239–3098, United States of America
- The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, 97239–3098, United States of America
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22
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Siler DA, Martini RP, Ward JP, Nelson JW, Borkar RN, Zuloaga KL, Liu JJ, Fairbanks SL, Raskin JS, Anderson VC, Dogan A, Wang RK, Alkayed NJ, Cetas JS. Protective role of p450 epoxyeicosanoids in subarachnoid hemorrhage. Neurocrit Care 2016; 22:306-19. [PMID: 25231529 DOI: 10.1007/s12028-014-0011-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND Patients recovering from aneurysmal subarachnoid hemorrhage (SAH) are at risk for developing delayed cerebral ischemia (DCI). Experimental and human studies implicate the vasoconstrictor P450 eicosanoid 20-hydroxyeicosatetraenoic acid (20-HETE) in the pathogenesis of DCI. To date, no studies have evaluated the role of vasodilator epoxyeicosatrienoic acids (EETs) in DCI. METHODS Using mass spectrometry, we measured P450 eicosanoids in cerebrospinal fluid (CSF) from 34 SAH patients from 1 to 14 days after admission. CSF eicosanoid levels were compared in patients who experienced DCI versus those who did not. We then studied the effect of EETs in a model of SAH using mice lacking the enzyme soluble epoxide hydrolase (sEH), which catabolizes EETs into their inactive diol. To assess changes in vessel morphology and cortical perfusion in the mouse brain, we used optical microangiography, a non-invasive coherence-based imaging technique. RESULTS Along with increases in 20-HETE, we found that CSF levels of 14,15-EET were elevated in SAH patients compared to control CSF, and levels were significantly higher in patients who experienced DCI compared to those who did not. Mice lacking sEH had elevated 14,15-EET and were protected from the delayed decrease in microvascular cortical perfusion after SAH, compared to wild type mice. CONCLUSIONS Our findings suggest that P450 eicosanoids play an important role in the pathogenesis of DCI. While 20-HETE may contribute to the development of DCI, 14,15-EET may afford protection against DCI. Strategies to enhance 14,15-EET, including sEH inhibition, should be considered as part of a comprehensive approach to prevent DCI.
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Affiliation(s)
- Dominic A Siler
- Department of Anesthesiology & Perioperative Medicine, Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA
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Nelson JW, Barnes AP, Kaul S, Ellison DH. Abstract P615: Hypertension-Dependent Reprogramming of the Endothelial Transcriptome. Hypertension 2015. [DOI: 10.1161/hyp.66.suppl_1.p615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Hypertension has drastic consequences for the cardiovascular system and especially for endothelial cell health. Clinically this is observed through the repeated finding that hypertension is associated with endothelial dysfunction. Despite this strong evidence that hypertension leads to impairment of endothelial function, the molecular events that give rise to endothelial dysfunction are poorly characterized. To better understand how hypertension affects the health and function of endothelial cells at the molecular level, we utilized a mouse model of spontaneous hypertension (BPH/2J) with the overarching hypothesis that hypertension causes the transcriptional reprogramming of endothelial cells leading to endothelial dysfunction. First, we non-invasively quantified endothelial function from hypertensive and normotensive (BPN/3J) mice by measuring flow-mediated vasodilation with high-frequency ultrasound. We found that hypertensive mice failed to dilate their femoral artery while normotensive control mice dilated their femoral artery 17 ± 8% (Mean ± SEM). Next, we acutely isolated cardiac endothelial cells by magnetic-assisted cell sorting for endothelial marker CD31. Through this technique, we enriched our sample for endothelial cells (as defined by expression of two endothelial-specific cell-surface markers CD31 and CD102) to 92 ± 1% compared to 9 ± 1% in pre-magnetically sorted cells. Finally, we isolated RNA and transcriptionally profiled the endothelial cells from normotensive and hypertensive mice (n=3 mice per group) with an average depth of 30 million reads per sample with RNAseq. We found that over 4000 genes were differentially expressed between groups (FDR cutoff of .01). Using Ingenuity Pathways Analysis (Qiagen), we identified multiple pathways that were dysregulated in endothelial cells exposed to hypertension including those related to immune function, cell morphology and cell-to-cell communication. This work represents one of the first studies to utilize cell-specific RNAseq to quantify how endothelial cells are transcriptionally reprogrammed in a pathological state. It is our hope that this work will lead to targeted therapeutics to improve endothelial function in patients with hypertension.
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Affiliation(s)
| | | | - Sanjiv Kaul
- Oregon Health and Science Univ, Portland, OR
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24
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Maruyama CLM, Leigh NJ, Nelson JW, McCall AD, Mellas RE, Lei P, Andreadis ST, Baker OJ. Stem Cell-Soluble Signals Enhance Multilumen Formation in SMG Cell Clusters. J Dent Res 2015; 94:1610-7. [PMID: 26285810 DOI: 10.1177/0022034515600157] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Saliva plays a major role in maintaining oral health. Patients with salivary hypofunction exhibit difficulty in chewing and swallowing foods, tooth decay, periodontal disease, and microbial infections. At this time, treatments for hyposalivation are limited to medications (e.g., muscarinic receptor agonists: pilocarpine and cevimeline) that induce saliva secretion from residual acinar cells as well as artificial salivary substitutes. Therefore, advancement of restorative treatments is necessary to improve the quality of life in these patients. Our previous studies indicated that salivary cells are able to form polarized 3-dimensional structures when grown on growth factor-reduced Matrigel. This basement membrane is rich in laminin-III (L1), which plays a critical role in salivary gland formation. Mitotically inactive feeder layers have been used previously to support the growth of many different cell types, as they provide factors necessary for cell growth and organization. The goal of this study was to improve salivary gland cell differentiation in primary cultures by using a combination of L1 and a feeder layer of human hair follicle-derived mesenchymal stem cells (hHF-MSCs). Our results indicated that the direct contact of mouse submandibular (mSMG) cell clusters and hHF-MSCs was not required for mSMG cells to form acinar and ductal structures. However, the hHF-MSC conditioned medium enhanced cell organization and multilumen formation, indicating that soluble signals secreted by hHF-MSCs play a role in promoting these features.
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Affiliation(s)
- C L M Maruyama
- School of Dentistry, University of Utah, Salt Lake City, UT, USA
| | - N J Leigh
- School of Dentistry, University of Utah, Salt Lake City, UT, USA
| | - J W Nelson
- School of Dentistry, University of Utah, Salt Lake City, UT, USA
| | - A D McCall
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - R E Mellas
- School of Dentistry, University of Utah, Salt Lake City, UT, USA
| | - P Lei
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - S T Andreadis
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA Department of Biomedical Engineering, School of Engineering and Applied Sciences, University at Buffalo, The State University of New York, Buffalo, NY, USA Center of Bioinformatics and Life Sciences, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - O J Baker
- School of Dentistry, University of Utah, Salt Lake City, UT, USA
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25
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Siler DA, Berlow YA, Kukino A, Davis CM, Nelson JW, Grafe MR, Ono H, Cetas JS, Pike M, Alkayed NJ. Soluble Epoxide Hydrolase in Hydrocephalus, Cerebral Edema, and Vascular Inflammation After Subarachnoid Hemorrhage. Stroke 2015; 46:1916-22. [PMID: 25991416 DOI: 10.1161/strokeaha.114.008560] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 04/23/2015] [Indexed: 12/27/2022]
Abstract
BACKGROUND AND PURPOSE Acute communicating hydrocephalus and cerebral edema are common and serious complications of subarachnoid hemorrhage (SAH), whose causes are poorly understood. Using a mouse model of SAH, we determined whether soluble epoxide hydrolase (sEH) gene deletion protects against SAH-induced hydrocephalus and edema by increasing levels of vasoprotective eicosanoids and suppressing vascular inflammation. METHODS SAH was induced via endovascular puncture in wild-type and sEH knockout mice. Hydrocephalus and tissue edema were assessed by T2-weighted magnetic resonance imaging. Endothelial activation was assessed in vivo using T2*-weighted magnetic resonance imaging after intravenous administration of iron oxide particles linked to anti-vascular cell adhesion molecule-1 antibody 24 hours after SAH. Behavioral outcome was assessed at 96 hours after SAH with the open field and accelerated rotarod tests. RESULTS SAH induced an acute sustained communicating hydrocephalus within 6 hours of endovascular puncture in both wild-type and sEH knockout mice. This was followed by tissue edema, which peaked at 24 hours after SAH and was limited to white matter fiber tracts. sEH knockout mice had reduced edema, less vascular cell adhesion molecule-1 uptake, and improved outcome compared with wild-type mice. CONCLUSIONS Genetic deletion of sEH reduces vascular inflammation and edema and improves outcome after SAH. sEH inhibition may serve as a novel therapy for SAH.
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Affiliation(s)
- Dominic A Siler
- From the Department of Anesthesiology and Perioperative Medicine, The Knight Cardiovascular Institute (D.A.S., C.M.D., J.W.N., M.R.G., N.J.A.), Department of Neurological Surgery (D.A.S., J.S.C.), Advanced Imaging Research Center (Y.A.B., A.K., M.P.), Oregon Health and Science University, Portland; Department of Neurosurgery, Nishijima Hospital, Numazu City, Sizuoka, Japan (H.O.); and Portland VA Medical Center, OR (J.S.C.)
| | - Yosef A Berlow
- From the Department of Anesthesiology and Perioperative Medicine, The Knight Cardiovascular Institute (D.A.S., C.M.D., J.W.N., M.R.G., N.J.A.), Department of Neurological Surgery (D.A.S., J.S.C.), Advanced Imaging Research Center (Y.A.B., A.K., M.P.), Oregon Health and Science University, Portland; Department of Neurosurgery, Nishijima Hospital, Numazu City, Sizuoka, Japan (H.O.); and Portland VA Medical Center, OR (J.S.C.)
| | - Ayaka Kukino
- From the Department of Anesthesiology and Perioperative Medicine, The Knight Cardiovascular Institute (D.A.S., C.M.D., J.W.N., M.R.G., N.J.A.), Department of Neurological Surgery (D.A.S., J.S.C.), Advanced Imaging Research Center (Y.A.B., A.K., M.P.), Oregon Health and Science University, Portland; Department of Neurosurgery, Nishijima Hospital, Numazu City, Sizuoka, Japan (H.O.); and Portland VA Medical Center, OR (J.S.C.)
| | - Catherine M Davis
- From the Department of Anesthesiology and Perioperative Medicine, The Knight Cardiovascular Institute (D.A.S., C.M.D., J.W.N., M.R.G., N.J.A.), Department of Neurological Surgery (D.A.S., J.S.C.), Advanced Imaging Research Center (Y.A.B., A.K., M.P.), Oregon Health and Science University, Portland; Department of Neurosurgery, Nishijima Hospital, Numazu City, Sizuoka, Japan (H.O.); and Portland VA Medical Center, OR (J.S.C.)
| | - Jonathan W Nelson
- From the Department of Anesthesiology and Perioperative Medicine, The Knight Cardiovascular Institute (D.A.S., C.M.D., J.W.N., M.R.G., N.J.A.), Department of Neurological Surgery (D.A.S., J.S.C.), Advanced Imaging Research Center (Y.A.B., A.K., M.P.), Oregon Health and Science University, Portland; Department of Neurosurgery, Nishijima Hospital, Numazu City, Sizuoka, Japan (H.O.); and Portland VA Medical Center, OR (J.S.C.)
| | - Marjorie R Grafe
- From the Department of Anesthesiology and Perioperative Medicine, The Knight Cardiovascular Institute (D.A.S., C.M.D., J.W.N., M.R.G., N.J.A.), Department of Neurological Surgery (D.A.S., J.S.C.), Advanced Imaging Research Center (Y.A.B., A.K., M.P.), Oregon Health and Science University, Portland; Department of Neurosurgery, Nishijima Hospital, Numazu City, Sizuoka, Japan (H.O.); and Portland VA Medical Center, OR (J.S.C.)
| | - Hirohisa Ono
- From the Department of Anesthesiology and Perioperative Medicine, The Knight Cardiovascular Institute (D.A.S., C.M.D., J.W.N., M.R.G., N.J.A.), Department of Neurological Surgery (D.A.S., J.S.C.), Advanced Imaging Research Center (Y.A.B., A.K., M.P.), Oregon Health and Science University, Portland; Department of Neurosurgery, Nishijima Hospital, Numazu City, Sizuoka, Japan (H.O.); and Portland VA Medical Center, OR (J.S.C.)
| | - Justin S Cetas
- From the Department of Anesthesiology and Perioperative Medicine, The Knight Cardiovascular Institute (D.A.S., C.M.D., J.W.N., M.R.G., N.J.A.), Department of Neurological Surgery (D.A.S., J.S.C.), Advanced Imaging Research Center (Y.A.B., A.K., M.P.), Oregon Health and Science University, Portland; Department of Neurosurgery, Nishijima Hospital, Numazu City, Sizuoka, Japan (H.O.); and Portland VA Medical Center, OR (J.S.C.)
| | - Martin Pike
- From the Department of Anesthesiology and Perioperative Medicine, The Knight Cardiovascular Institute (D.A.S., C.M.D., J.W.N., M.R.G., N.J.A.), Department of Neurological Surgery (D.A.S., J.S.C.), Advanced Imaging Research Center (Y.A.B., A.K., M.P.), Oregon Health and Science University, Portland; Department of Neurosurgery, Nishijima Hospital, Numazu City, Sizuoka, Japan (H.O.); and Portland VA Medical Center, OR (J.S.C.)
| | - Nabil J Alkayed
- From the Department of Anesthesiology and Perioperative Medicine, The Knight Cardiovascular Institute (D.A.S., C.M.D., J.W.N., M.R.G., N.J.A.), Department of Neurological Surgery (D.A.S., J.S.C.), Advanced Imaging Research Center (Y.A.B., A.K., M.P.), Oregon Health and Science University, Portland; Department of Neurosurgery, Nishijima Hospital, Numazu City, Sizuoka, Japan (H.O.); and Portland VA Medical Center, OR (J.S.C.).
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Abstract
AIMS Peroxisomes are highly adaptable and dynamic organelles, adjusting their size, number, and enzyme composition to changing environmental and metabolic demands. We determined whether peroxisomes respond to ischemia, and whether peroxisomal biogenesis is an adaptive response to cerebral ischemia. RESULTS Focal cerebral ischemia induced peroxisomal biogenesis in peri-infarct neurons, which was associated with a corresponding increase in peroxisomal antioxidant enzyme catalase. Peroxisomal biogenesis was also observed in primary cultured cortical neurons subjected to ischemic insult induced by oxygen-glucose deprivation (OGD). A catalase inhibitor increased OGD-induced neuronal death. Moreover, preventing peroxisomal proliferation by knocking down dynamin-related protein 1 (Drp1) exacerbated neuronal death induced by OGD, whereas enhancing peroxisomal biogenesis pharmacologically using a peroxisome proliferator-activated receptor-alpha agonist protected against neuronal death induced by OGD. INNOVATION This is the first documentation of ischemia-induced peroxisomal biogenesis in mammalian brain using a combined in vivo and in vitro approach, electron microscopy, high-resolution laser-scanning confocal microscopy, and super-resolution structured illumination microscopy. CONCLUSION Our findings suggest that neurons respond to ischemic injury by increasing peroxisome biogenesis, which serves a protective function, likely mediated by enhanced antioxidant capacity of neurons.
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Affiliation(s)
- Jennifer M Young
- 1 Department of Anesthesiology & Perioperative Medicine, The Knight Cardiovascular Institute, Oregon Health & Science University , Portland, Oregon
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Nelson JW, Young JM, Borkar RN, Woltjer RL, Quinn JF, Silbert LC, Grafe MR, Alkayed NJ. Role of soluble epoxide hydrolase in age-related vascular cognitive decline. Prostaglandins Other Lipid Mediat 2014; 113-115:30-7. [PMID: 25277097 DOI: 10.1016/j.prostaglandins.2014.09.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Revised: 08/21/2014] [Accepted: 09/19/2014] [Indexed: 01/20/2023]
Abstract
P450 eicosanoids are important regulators of the cerebral microcirculation, but their role in cerebral small vessel disease is unclear. We tested the hypothesis that vascular cognitive impairment (VCI) is linked to reduced cerebral microvascular eicosanoid signaling. We analyzed human brain tissue from individuals formerly enrolled in the Oregon Brain Aging Study, who had a history of cognitive impairment histopathological evidence of microvascular disease. VCI subjects had significantly higher lesion burden both on premortem MRI and postmortem histopathology compared to age- and sex-matched controls. Mass spectrometry-based eicosanoid analysis revealed that 14,15-dihydroxyeicosatrienoic acid (DHET) was elevated in cortical brain tissue from VCI subjects. Immunoreactivity of soluble epoxide hydrolase (sEH), the enzyme responsible for 14,15-DHET formation, was localized to cerebral microvascular endothelium, and was enhanced in microvessels of affected tissue. Finally, we evaluated the genotype frequency of two functional single nucleotide polymorphisms of sEH gene EPHX2 in VCI and control groups. Our findings support a role for sEH and a potential benefit from sEH inhibitors in age-related VCI.
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Affiliation(s)
- Jonathan W Nelson
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR 97239-3098, USA; The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR 97239-3098, USA
| | - Jennifer M Young
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR 97239-3098, USA
| | - Rohan N Borkar
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR 97239-3098, USA
| | - Randy L Woltjer
- Department of Pathology, Oregon Health & Science University, Portland, OR 97239-3098, USA
| | - Joseph F Quinn
- Layton Aging and Alzheimer's Disease Center, Department of Neurology, Oregon Health & Science University, Portland, OR 97239-3098, USA
| | - Lisa C Silbert
- Layton Aging and Alzheimer's Disease Center, Department of Neurology, Oregon Health & Science University, Portland, OR 97239-3098, USA
| | - Marjorie R Grafe
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR 97239-3098, USA; Department of Pathology, Oregon Health & Science University, Portland, OR 97239-3098, USA
| | - Nabil J Alkayed
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR 97239-3098, USA; Layton Aging and Alzheimer's Disease Center, Department of Neurology, Oregon Health & Science University, Portland, OR 97239-3098, USA; The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR 97239-3098, USA.
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28
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Martini RP, Ward J, Siler DA, Eastman JM, Nelson JW, Borkar RN, Alkayed NJ, Dogan A, Cetas JS. Genetic variation in soluble epoxide hydrolase: association with outcome after aneurysmal subarachnoid hemorrhage. J Neurosurg 2014; 121:1359-66. [PMID: 25216066 DOI: 10.3171/2014.7.jns131990] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
OBJECT Patients with aneurysmal subarachnoid hemorrhage (SAH) are at high risk for delayed cerebral ischemia (DCI) and stroke. Epoxyeicosatrienoic acids (EETs) play an important role in cerebral blood flow regulation and neuroprotection after brain injury. Polymorphisms in the gene for the enzyme soluble epoxide hydrolase (sEH), which inactivates EETs, are associated with ischemic stroke risk and neuronal survival after ischemia. This prospective observational study of patients with SAH compares vital and neurologic outcomes based on functional polymorphisms of sEH. METHODS Allelic discrimination based on quantitative real-time polymerase chain reaction was used to differentiate wild-type sEH from K55R heterozygotes (predictive of increased sEH activity and reduced EETs) and R287Q heterozygotes (predictive of decreased sEH activity and increased EETs). The primary outcome was new stroke after SAH. Secondary outcomes were death, Glasgow Outcome Scale score, and neurological deterioration attributable to DCI. RESULTS Multivariable logistic regression models adjusted for age at admission and Glasgow Coma Scale scores revealed an increase in the odds of new stroke (OR 5.48 [95% CI 1.51-19.91]) and death (OR 7.52 [95% CI 1.27-44.46]) in the K55R group, but no change in the odds of new stroke (OR 0.56 [95% CI 0.16-1.96]) or death (OR 3.09 [95% CI 0.51-18.52]) in patients with R287Q genotype, compared with wild-type sEH. The R287Q genotype was associated with reduced odds of having a Glasgow Outcome Scale score of ≤ 3 (OR 0.23 [95% CI 0.06-0.82]). There were no significant differences in the odds of neurological deterioration due to DCI. CONCLUSIONS Genetic polymorphisms of sEH are associated with neurological and vital outcomes after aneurysmal SAH.
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Affiliation(s)
- Ross P Martini
- Departments of Anesthesiology & Perioperative Medicine and
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29
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Abstract
Resolvins are potent anti-inflammatory mediators derived from ω-3 fatty acids. Results from our previous studies indicated that resolvin D1 (RvD1) blocks pro-inflammatory responses in salivary glands. Furthermore, RvD1 enhances salivary epithelial integrity, demonstrating its potential use for the restoration of salivary gland function in Sjögren's syndrome (SS). We investigated whether the RvD1 biosynthetic machinery (e.g., cytosolic phospholipase A2, calcium-independent phospholipase A2, 12/15 and 5-lipoxygenase) is expressed in mouse submandibular glands (mSMG), using qPCR and Western blot analyses. Additionally, we determined the localization of RvD1 biosynthetic machinery in mSMG and human minor salivary glands (hMSG), with and without SS, using confocal microscopy. Finally, we measured RvD1 levels in cell supernatants from mSMG cell cultures and freshly isolated mSMG cells, with and without SS, using ELISA. Our results indicate that: (1) RvD1 machinery is expressed in mouse and human salivary glands; (2) polar distribution of RvD1 biosynthetic machinery is lost in hMSG with SS; (3) RvD1 levels in mSMG cell culture supernatants increased with time; and (4) RvD1 levels in mSMG cell supernatants, with and without SS, were similar. These studies demonstrate that the RvD1 biosynthesis machinery is expressed and functional in salivary glands with and without SS.
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MESH Headings
- Animals
- Arachidonate 12-Lipoxygenase/analysis
- Arachidonate 12-Lipoxygenase/metabolism
- Arachidonate 15-Lipoxygenase/analysis
- Arachidonate 15-Lipoxygenase/metabolism
- Arachidonate 5-Lipoxygenase/analysis
- Arachidonate 5-Lipoxygenase/metabolism
- Cell Culture Techniques
- Cell Membrane/enzymology
- Cells, Cultured
- Cytosol/enzymology
- Docosahexaenoic Acids/analysis
- Docosahexaenoic Acids/biosynthesis
- Epithelium/metabolism
- Female
- Humans
- Mice
- Mice, Inbred C57BL
- Mice, Inbred NOD
- Mice, Inbred Strains
- Phospholipases A2, Calcium-Independent/analysis
- Phospholipases A2, Calcium-Independent/metabolism
- Phospholipases A2, Cytosolic/analysis
- Phospholipases A2, Cytosolic/metabolism
- Salivary Glands, Minor/metabolism
- Salivary Glands, Minor/pathology
- Sjogren's Syndrome/metabolism
- Sjogren's Syndrome/pathology
- Submandibular Gland/cytology
- Submandibular Gland/metabolism
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Affiliation(s)
- N J Leigh
- Department of Oral Biology, University at Buffalo, The State University of New York, Buffalo, NY 14214-3092, USA
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30
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Jones CM, Baker-Groberg SM, Cianchetti FA, Glynn JJ, Healy LD, Lam WY, Nelson JW, Parrish DC, Phillips KG, Scott-Drechsel DE, Tagge IJ, Zelaya JE, Hinds MT, McCarty OJT. Measurement science in the circulatory system. Cell Mol Bioeng 2013; 7:1-14. [PMID: 24563678 DOI: 10.1007/s12195-013-0317-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The dynamics of the cellular and molecular constituents of the circulatory system are regulated by the biophysical properties of the heart, vasculature and blood cells and proteins. In this review, we discuss measurement techniques that have been developed to characterize the physical and mechanical parameters of the circulatory system across length scales ranging from the tissue scale (centimeter) to the molecular scale (nanometer) and time scales of years to milliseconds. We compare the utility of measurement techniques as a function of spatial resolution and penetration depth from both a diagnostic and research perspective. Together, this review provides an overview of the utility of measurement science techniques to study the spatial systems of the circulatory system in health and disease.
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Affiliation(s)
- Casey M Jones
- Department of Biomedical Engineering, Oregon Health & Science University, Portland OR ; Department of Chemistry, Lewis & Clark College, Portland OR
| | | | - Flor A Cianchetti
- Department of Biomedical Engineering, Oregon Health & Science University, Portland OR
| | - Jeremy J Glynn
- Department of Biomedical Engineering, Oregon Health & Science University, Portland OR
| | - Laura D Healy
- Department of Cell & Developmental Biology, Oregon Health & Science University, Portland OR
| | - Wai Yan Lam
- Department of Biomedical Engineering, Oregon Health & Science University, Portland OR
| | - Jonathan W Nelson
- Division of Cardiology, Knight Cardiovascular Institute, Oregon Health & Science University, Portland OR
| | - Diana C Parrish
- Department of Physiology & Pharmacology, Oregon Health & Science University, Portland OR
| | - Kevin G Phillips
- Department of Biomedical Engineering, Oregon Health & Science University, Portland OR
| | | | - Ian J Tagge
- Department of Biomedical Engineering, Oregon Health & Science University, Portland OR ; Advanced Imaging Research Center, Oregon Health & Science University, Portland OR
| | - Jaime E Zelaya
- Department of Biomedical Engineering, Oregon Health & Science University, Portland OR
| | - Monica T Hinds
- Department of Biomedical Engineering, Oregon Health & Science University, Portland OR
| | - Owen J T McCarty
- Department of Biomedical Engineering, Oregon Health & Science University, Portland OR ; Department of Cell & Developmental Biology, Oregon Health & Science University, Portland OR ; Division of Hematology & Medical Oncology, Oregon Health & Science University, Portland OR
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31
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Nelson JW, Subrahmanyan RM, Summers SA, Xiao X, Alkayed NJ. Soluble epoxide hydrolase dimerization is required for hydrolase activity. J Biol Chem 2013; 288:7697-7703. [PMID: 23362272 DOI: 10.1074/jbc.m112.429258] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Soluble epoxide hydrolase (sEH) plays a key role in the metabolic conversion of the protective eicosanoid 14,15-epoxyeicosatrienoic acid to 14,15-dihydroxyeicosatrienoic acid. Accordingly, inhibition of sEH hydrolase activity has been shown to be beneficial in multiple models of cardiovascular diseases, thus identifying sEH as a valuable therapeutic target. Recently, a common human polymorphism (R287Q) was identified that reduces sEH hydrolase activity and is localized to the dimerization interface of the protein, suggesting a relationship between sEH dimerization and activity. To directly test the hypothesis that dimerization is essential for the proper function of sEH, we generated mutations within the sEH protein that would either disrupt or stabilize dimerization. We quantified the dimerization state of each mutant using a split firefly luciferase protein fragment-assisted complementation system. The hydrolase activity of each mutant was determined using a fluorescence-based substrate conversion assay. We found that mutations that disrupted dimerization also eliminated hydrolase enzymatic activity. In contrast, a mutation that stabilized dimerization restored hydrolase activity. Finally, we investigated the kinetics of sEH dimerization and found that the human R287Q polymorphism was metastable and capable of swapping dimer partners faster than the WT enzyme. These results indicate that dimerization is required for sEH hydrolase activity. Disrupting sEH dimerization may therefore serve as a novel therapeutic strategy for reducing sEH hydrolase activity.
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Affiliation(s)
- Jonathan W Nelson
- Departments of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon 97239-3098; Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon 97239-3098
| | - Rishi M Subrahmanyan
- Departments of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon 97239-3098
| | - Sol A Summers
- Departments of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon 97239-3098
| | - Xiangshu Xiao
- Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon 97239-3098
| | - Nabil J Alkayed
- Departments of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon 97239-3098.
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Gupta NC, Davis CM, Nelson JW, Young JM, Alkayed NJ. Soluble epoxide hydrolase: sex differences and role in endothelial cell survival. Arterioscler Thromb Vasc Biol 2012; 32:1936-42. [PMID: 22723436 DOI: 10.1161/atvbaha.112.251520] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Sex differences in cerebral ischemic injury are, in part, attributable to the differences in cerebrovascular perfusion. We determined whether the brain microvascular endothelial cells (ECs) isolated from the female brain are more resistant to ischemic injury compared with male ECs, and whether the difference is attributable to lower expression of soluble epoxide hydrolase and higher levels of vasoprotective epoxyeicosatrienoic acids (EETs). We also determined whether protection by EETs is linked to the inhibition of rho-kinase (ROCK). METHODS AND RESULTS EC ischemic damage was measured after oxygen-glucose deprivation (OGD) using propidium iodide (PI) and cleaved caspase-3 labeling. Expression of soluble epoxide hydrolase was determined by quantitative polymerase chain reaction and immunocytochemistry, EETs levels by liquid chromatography-tandem mass spectrometry, and ROCK activity by ELISA. EC damage was higher in males compared with females, which correlated with higher soluble epoxide hydrolase mRNA, stronger immunoreactivity, and lower EETs compared with female ECs. Inhibition of soluble epoxide hydrolase abolished the sex difference in EC damage. ROCK activity was higher in male versus female ECs after OGD, and sex differences in EC damage and ROCK activity were abolished by 14,15-EET and ROCK inhibition. CONCLUSIONS Sex differences in ischemic brain injury are, in part, attributable to differences in EET-mediated inhibition of EC ROCK activation after ischemia.
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Affiliation(s)
- Nandita C Gupta
- Division of Cardiovascular Medicine, Oregon Health & Science University, 3181 S.W. Sam Jackson Pk. Rd, Portland, OR 97239-3098, USA
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Fairbanks SL, Young JM, Nelson JW, Davis CM, Koerner IP, Alkayed NJ. Mechanism of the sex difference in neuronal ischemic cell death. Neuroscience 2012; 219:183-91. [PMID: 22641086 DOI: 10.1016/j.neuroscience.2012.05.048] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 05/15/2012] [Accepted: 05/17/2012] [Indexed: 12/20/2022]
Abstract
BACKGROUND Stroke risk and outcome are different in men and women. We hypothesized that this is partly due to an inherent difference in susceptibility to ischemia between neurons from male vs. female brains. We tested whether neurons from male rodents are more susceptible to in-vitro ischemia than cells from females, and if this is related to increased expression of soluble epoxide hydrolase (sEH). sEH contributes to neuronal cell death by inactivating neuroprotective epoxyeicosatrienoic acids (EETs). METHODS Rodent cortical neurons were cultured, and exposed to oxygen-glucose deprivation (OGD); then cell death was measured. EETs levels were determined by LC-MS/MS. Expression of sEH-encoding ephx2 was determined by qRT-PCR. Western blotting, immunocytochemistry, and hydrolase activity assay assessed protein expression and activity. RESULTS Cell death after OGD was higher in neurons from males vs. females, which correlated with higher ephx2 mRNA and stronger sEH immunoreactivity. However, EETs levels were similar in both sexes and pharmacological inhibition of the hydrolase domain of sEH did not abolish the sex difference in cell death. Genetic knockout of sEH in mice abolished the sex difference observed in neurons isolated from these mice after OGD. CONCLUSIONS Cultured cortical neurons from females are more resistant to ischemia than neurons from males. Neurons from females have less sEH activity compared to neurons from males at baseline, although sEH levels were not measured after OGD. While pharmacological inhibition of the hydrolase domain of sEH does not affect cell death, knockout of the gene encoding sEH eradicates the sex difference seen in wild-type neurons, suggesting a role for further study of the lesser-known phosphatase domain of sEH and its role in sexual dimorphism in neuronal sensitivity to ischemia.
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Affiliation(s)
- S L Fairbanks
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239-3098, USA
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Nelson JW, Alkayed NJ. Soluble Epoxide Hydrolase as a Stroke Target. Transl Stroke Res 2012. [DOI: 10.1007/978-1-4419-9530-8_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Abstract
Although changes in diet and physical activity are undoubtedly key causal factors related to the increase in obesity, there is growing interest in the possibility that endocrine disrupting chemicals (EDCs) may affect obesity-related pathways by altering cell signalling involved in weight and lipid homeostasis. Proposed mechanisms that could underlie associations between EDCs and obesity include effects on thyroid and steroid hormones, and activation of peroxisome proliferator-activated receptors, which play a major role in adipocyte differentiation and energy storage. Most evidence supporting the hypothesis that EDCs affect obesity comes from laboratory studies. We summarize the limited epidemiological literature on the topic, including prospective studies of human prenatal exposure to EDCs. We also present findings from a cross-sectional study of levels of six phthalate metabolites and body mass index (BMI) and waist circumference (WC), using data from the U.S. National Health and Nutrition Examination Survey. We found positive associations between BMI and WC among adult males for most phthalate metabolites. For example, in males aged 20-59, the adjusted mean BMI across quartiles of mono-benzyl phthalate was 26.7, 27.2, 28.4, 29.0 (p-trend = 0.0002). In females, BMI and WC increased with quartiles of mono-ethyl phthalate in 12-19 year olds (adjusted mean BMI = 22.9, 23.8, 24.1, 24.7, p-trend = 0.03), and a similar but less strong pattern was seen in 20-59 year olds. By contrast, higher levels of mono-2-ethylhexyl phthalate were associated with lower BMI in adolescent girls and females aged 20-59. This exploratory analysis found several associations between phthalate metabolites and obesity, including notable differences by gender. However, the cross-sectional data are a limitation. Additional prospective studies of the association between exposures to EDCs, especially during development, and obesity are warranted. As this field of research advances, there are challenging methodological questions that must be considered by both epidemiologists and toxicologists.
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Affiliation(s)
- E E Hatch
- Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA.
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Oommen KJ, Gilson GE, Nelson JW, Couch JR. A study to determine the accuracy of a computerized algorithm for interpretation of EEGs. J Okla State Med Assoc 2001; 94:400-2. [PMID: 11577629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
The main use of computerized EEG has been in sleep studies. A comprehensive system of interpreting routine EEGs by computers has not yet been developed and is technically difficult. We have tried to incorporate computers in the analysis and interpretation of EEGs by using information obtained from visual analysis of EEG in the present work. The purpose of this study was to determine the accuracy of such an algorithm. An electroencephalographer visually analyzed routine EEGs and the data was entered into an EEG Worksheet. The electroencephalographer then interpreted the data and a report was dictated and transcribed. Data from the EEG Worksheet was entered into a computer for interpretation, clinical correlation, and report preparation. Results indicate that the algorithm used with the EEG Worksheet can correctly interpret and clinically correlate visually-analyzed EEG data entered into a computer and reduce time for EEG report generation.
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Affiliation(s)
- K J Oommen
- University of Oklahoma College of Medicine, USA
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Nelson JW. A call to arms: the cytokine selection service. Sci STKE 2001; 2001:pe2. [PMID: 11752664 DOI: 10.1126/stke.2001.91.pe2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The process by which naïve T helper (T(H)) cells differentiate into the T(H)1 and T(H)2 subtypes has been well studied. However, there remain some unresolved issues pertaining to the requirements for the initial step of T(H) cell differentiation. Much debate exists about whether the roles of cytokines include the forcing of the initial steps of differentiation on naïve T(H) cells, termed "instruction," or whether cytokines act in a supportive role, termed "selection," whereby newly differentiating T(H) cells are given the proper signals for survival and proliferation. A recent paper by Mullen et al., which helps delineate the role of cytokines in T(H)1 cell development, is addressed by Nelson; it appears that cytokines act in the selection stage of T(H) cell maturation.
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Affiliation(s)
- J W Nelson
- American Association for the Advancement of Science, Science's Signal Transduction Knowledge Environment, Washington, DC 20005 USA.
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Affiliation(s)
- J W Nelson
- Abbot Northwestern Hospital, New Brighton, Minnesota, USA
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Lehmberg E, Traina JA, Chakel JA, Chang RJ, Parkman M, McCaman MT, Murakami PK, Lahidji V, Nelson JW, Hancock WS, Nestaas E, Pungor E. Reversed-phase high-performance liquid chromatographic assay for the adenovirus type 5 proteome. J Chromatogr B Biomed Sci Appl 1999; 732:411-23. [PMID: 10517364 DOI: 10.1016/s0378-4347(99)00316-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
An RP-HPLC assay was developed for a recombinant adenovirus type 5. During chromatography, intact adenovirus dissociated into its structural components (DNA and proteins) and the viral proteome was separated yielding a characteristic fingerprint. The individual components were identified by matrix-assisted laser desorption ionization time-of-flight mass spectroscopy, N-terminal sequencing and amino acid composition. The assay was utilized to measure adenovirus particle concentration through quantification of structural proteins. Each structural protein provided independent measurement of virus concentration allowing verification of accuracy. The assay sensitivity is at or below 2 x 10(8) particles. Contrary to the benchmark spectrophotometric assay, the RP-HPLC assay was shown to be insensitive to contaminants common for partially purified adenovirus preparations.
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Affiliation(s)
- E Lehmberg
- Berlex Laboratories, Inc., Richmond, CA 94804-0099, USA.
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Abstract
Janus kinases (JAK) play a crucial role in the initial steps of cytokine signaling. Each of the four members (JAK1, JAK2, JAK3, TYK2) of this non-receptor tyrosine kinase family is indispensable for the effects of distinct cytokines. Moreover, recent reports have added to our knowledge on their highly specific functions: JAK3 knockout mice and JAK3 deficient patients cannot signal through the interleukin-2,4,7,9, or 15 receptors and suffer from severe combined immunodeficiency (SCID). JAK1 and JAK2 knockout mice do not survive, their cells again showing distinct patterns of cytokine signaling deficits. At the other end of the spectrum, JAK fusion proteins have been shown to play a role in leukemias. In addition, a new class of JAK-specific inhibitors was described by several groups, the CIS/SOCS/Jab family. This review on the rapidly growing field focuses on JAK function and regulation, and on their emerging role in development and human disease.
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Affiliation(s)
- M Aringer
- Lymphocyte Biology Section, Arthritis and Rheumatism Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892-1820, USA
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Pungor E, Files JG, Gabe JD, Do LT, Foley WP, Gray JL, Nelson JW, Nestaas E, Taylor JL, Grossberg SE. A novel bioassay for the determination of neutralizing antibodies to IFN-beta1b. J Interferon Cytokine Res 1998; 18:1025-30. [PMID: 9877445 DOI: 10.1089/jir.1998.18.1025] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We have adapted the new MxA gene-induction bioassay to measure neutralizing antibodies to interferon-beta1b (IFN-beta1b, the active ingredient in Betaseron) in sera from patients treated with Betaseron. This antibody assay has been validated to quantify neutralizing titers of 1:20 and above, with a precision of +/- 0.20 in log10. We have used this MxA gene-induction antibody assay to reinvestigate serum samples from multiple sclerosis (MS) patients treated with Betaseron. The titers measured were closely comparable to those obtained in antiviral assays. Data obtained by both methods show that neutralizing antibodies may appear and subsequently disappear over time in the sera of some patients treated with Betaseron. Sera from some patients contain binding antibodies to IFN-beta1b. It was shown that binding antibody titers do not correlate quantitatively or qualitatively with neutralizing antibody titers, and indeed, a number of patients develop high levels of binding antibodies but never form measurable levels of neutralizing antibodies.
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Affiliation(s)
- E Pungor
- Berlex Laboratories, Inc., Richmond, CA 94804-0099, USA.
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Nelson JW, Zhu J, Smith CC, Kulka M, Aurelian L. ATP and SH3 binding sites in the protein kinase of the large subunit of herpes simplex virus type 2 of ribonucleotide reductase (ICP10). J Biol Chem 1996; 271:17021-7. [PMID: 8663276 DOI: 10.1074/jbc.271.29.17021] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The large subunit of herpes simplex virus type 2 ribonucleotide reductase (ICP10) is a multifunctional protein. It consists of a ribonucleotide reductase and a serine/threonine protein kinase (PK) domain, which has three proline-rich motifs consistent with SH3-binding sites at positions 140, 149, and 396. We used site-directed mutagenesis to identify amino acids required for kinase activity and interaction with signaling proteins. Mutation of Lys176 or Lys259 reduced PK activity (5-8-fold) and binding of the 14C-labeled ATP analog rho-fluorosulfonylbenzoyl 5'-adenosine (FSBA) but did not abrogate them. Enzymatic activity and FSBA binding were abrogated by mutation of both Lys residues, suggesting that either one can bind ATP. Mutation of Glu209 (PK catalytic motif III) virtually abrogated kinase activity in the presence of Mg2+ or Mn2+ ions, suggesting that Glu209 functions in ion-dependent PK activity. ICP10 bound the adaptor protein Grb2 in vitro. Mutation of the ICP10 proline-rich motifs at positions 396 and 149 reduced Grb2 binding 20- and 2-fold, respectively. Binding was abrogated by mutation of both motifs. Grb2 binding to wild type ICP10 was competed by a peptide for the Grb2 C-terminal SH3 motif, indicating that it involves the Grb2 C-terminal SH3.
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Affiliation(s)
- J W Nelson
- Department of Pharmacology and Experimental Therapeutics, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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Peng T, Hunter JR, Nelson JW. The novel protein kinase of the RR1 subunit of herpes simplex virus has autophosphorylation and transphosphorylation activity that differs in its ATP requirements for HSV-1 and HSV-2. Virology 1996; 216:184-96. [PMID: 8614985 DOI: 10.1006/viro.1996.0045] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The large subunit of herpes simplex virus (HSV) ribonucleotide reductase (RR1) designated ICP6 and ICP10 for HSV-1 and HSV-2, respectively, has a novel protein kinase (PK) enzymatic activity. ICP10 is localized on the cell surface, a localization that depends on an intact transmembrane (TM) segment. We used immunocomplex PK assays to examine the PK activity of ICP10 in stably transfected eukaryotic cells. Activity was distinct from that of casein kinase II (CKII) in that it did not require monovalent ions and was not inhibited by zinc sulfate. PK activity was eliminated by deletion of the conserved PK catalytic motifs or of the TM segment and it was significantly impaired by mutation of the invariant Lys (Lys176). Loss of PK activity by Lys176 mutation resulted in the failure to bind ATP. A truncated ICP10 PK expressed in bacteria (pp29 1a1) retained auto- and transphosphorylating activity (for calmodulin) after purification to apparent homogeneity. PK activity was also absent in cells infected with a recombinant virus (ICP10 delta PK) deleted in the ICP10 PK catalytic motifs. In cells infected with HSV-1 or HSV-2, RR1 had auto- and transphosphorylating activity for the small subunit of HSV ribonucleotide reductase (RR2) and immunoglobulin G (IgG). Comparing the PK activity of ICP6 and ICP10 we found that ICP6 requires five-fold higher concentrations of [gamma-32P]ATP than ICP10 and both enzymes are Mn2+ dependent, which is also different from CKII that is primarily Mg2+-dependent. Similar results were obtained for various HSV strains and in different cell lines. The data are consistent with the conclusion that the RR1 PK activity is intrinsic.
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Affiliation(s)
- T Peng
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore 21201, USA
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Dyer JM, Nelson JW, Murai N. Extensive modifications for methionine enhancement in the beta-barrels do not alter the structural stability of the bean seed storage protein phaseolin. J Protein Chem 1995; 14:665-78. [PMID: 8747427 DOI: 10.1007/bf01886905] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Common beans are widely utilized as a food source, yet are low in the essential amino acid methionine. As an initial step to overcome this defect the methionine content of the primary bean seed storage protein phaseolin was increased by replacing 20 evolutionarily variant hydrophobic residues with methionine and inserting short, methionine-rich sequences into turn and loop regions of the protein structure. Methionine enhancement ranged from 5 to 30 residues. An Escherichia coli expression system was developed to characterize the structural stability of the mutant proteins. Proteins of expected sizes were obtained for all constructs except for negative controls, which were rapidly degraded in E. coli. Thermal denaturation of the purified proteins demonstrated that both wild-type and mutant phaseolin proteins denatured reversibly at approximately 61 degrees C. In addition, urea denaturation experiments of the wild-type and a mutant protein (with 30 additional methionines) confirmed that the structural stability of the proteins was very similar. Remarkably, these results indicate that the phaseolin protein tolerates extensive modifications, including 20 substitutions and two loop inserts for methionine enhancement in the beta-barrel and loop structures, with extremely small effects on protein stability.
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Affiliation(s)
- J M Dyer
- Department of Biochemistry, Louisiana State University, Baton Rouge 70803, USA
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Butler SL, Doherty CJ, Hughes JE, Nelson JW, Govan JR. Burkholderia cepacia and cystic fibrosis: do natural environments present a potential hazard? J Clin Microbiol 1995; 33:1001-4. [PMID: 7540623 PMCID: PMC228085 DOI: 10.1128/jcm.33.4.1001-1004.1995] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
An environmental survey of 55 sites yielded only 12 Burkholderia cepacia isolates, none of which displayed the phenotypic properties of a multiresistant epidemic strain associated with pulmonary colonization in patients with cystic fibrosis. Although the environment probably poses a low risk for patients with cystic fibrosis as a source of B. cepacia, the pathogenic potential of individual environmental strains remains unclear. We advise caution in the development of B. cepacia as a biocontrol agent.
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Affiliation(s)
- S L Butler
- Department of Medical Microbiology, University of Edinburgh Medical School, Scotland
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Abstract
Crystallographic studies indicate that the loop between alpha-helix 8 and beta-strand H (the 8H loop) which borders the effector site of Bacillus stearothermophilus phosphofructokinase (BsPFK) is involved in the allosteric mechanism of the enzyme [Schirmer, T., and Evans, P.R. (1990) Nature 343, 140-145]. The residue at one end of this loop, glycine 212, has been proposed to be a pivot about which the loop hinges. Using site-directed mutagenesis, glycine 212 was replaced with valine (G212V). Steady-state kinetic analysis and ligand binding studies on the altered and native PFKs showed that the G212V substitution resulted in discernible changes at the effector site. The mutated PFK required a 3-fold higher concentration of the allosteric inhibitor phosphoenolpyruvate than did the native enzyme to cause the same level of inhibition. The altered PFK had a 2-fold higher dissociation constant for the allosteric activator GDP than the wild-type enzyme. More importantly, whereas the native PFK was fully activated by 1 mM GDP from its PEP-inhibited T-state, the altered enzyme was only marginally activated. On the other hand, the G212V mutation resulted in no changes at the catalytic site of BsPFK. The catalytic rate constant kcat remained unchanged. The altered PFK had the same Km values for ATP and fructose-6-phosphate (Fru-6-P) as did the wild-type enzyme. Furthermore, starting from the same PEP-inhibited T-state, both enzymes gave identical sigmoidal responses to increasing Fru-6-P concentration, indicating that Fru-6-P can activate both to the R-state.
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Affiliation(s)
- X Zhu
- Department of Biochemistry, Louisiana State University, Baton Rouge 70803
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Abstract
The structures formed by peptide models of the N-terminal domain of the nucleolar protein nucleolin were studied by CD and nmr. The sequences of the peptides are based on the putative nucleic acid binding sequence motif TPAKK. The peptides TP1 and TP2 have the sequence acetyl-G(ATPAKKAA)nG-amide, with n = 1 and 2, respectively. CD measurements indicate structural changes in both peptides when the lysine side chains are uncharged by increasing the pH or acetylation of the side-chain amines. When trifluoroethanol (TFE) is added, more extensive structural changes are observed, resembling helical structure based on nmr nuclear Overhauser effect (NOE) and C alpha proton chemical shift changes, and CD spectra. The structure formed in 0.5M NaClO4 as observed by nmr is similar to that when the lysine side chains are acetylated, due presumably to interactions of perchlorate ion with side-chain charges on lysines. The helical structure observed in TPAKK motifs may be stabilized via N-capping interactions involving threonine. The structures observed in TFE suggest that the Thr-Pro sequence initiates short helical segments in TPAKK motifs, and these helical structures might interact with nucleic acids, presumably via interactions between lysines and threonines of nucleolin.
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Affiliation(s)
- X Xu
- Department of Biochemistry, Louisiana State University, Baton Rouge 70803-1806
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Simpson IN, Finlay J, Winstanley DJ, Dewhurst N, Nelson JW, Butler SL, Govan JR. Multi-resistance isolates possessing characteristics of both Burkholderia (Pseudomonas) cepacia and Burkholderia gladioli from patients with cystic fibrosis. J Antimicrob Chemother 1994; 34:353-61. [PMID: 7530242 DOI: 10.1093/jac/34.3.353] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Multi-resistant strains from three UK centres, previously identified as Burkholderia (formerly Pseudomonas) cepacia, and associated with morbidity, mortality and transmission among patients with cystic fibrosis have been further characterised. Biochemical tests and fatty acid analyses indicate these strains to possess some characteristics atypical of B. cepacia but bearing close resemblance to Burkholderia gladioli, an organism previously regarded solely as a plant pathogen and a hindrance to the identification of B. cepacia. In contrast to the majority of reference strains, all multi-resistant clinical isolates possessed rough lipopolysaccharide which may be a major factor responsible for their increased antibiotic resistance and virulence. In view of the potential clinical and social problems in CF patients posed by these multi-resistant strains, it would seem prudent to consider the isolation of either B. cepacia or B. gladioli as of equal significance.
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Nelson JW, Creighton TE. Reactivity and ionization of the active site cysteine residues of DsbA, a protein required for disulfide bond formation in vivo. Biochemistry 1994; 33:5974-83. [PMID: 8180227 DOI: 10.1021/bi00185a039] [Citation(s) in RCA: 203] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
DsbA is a periplasmic protein of Escherichia coli that appears to be the immediate donor of disulfide bonds to proteins that are secreted. Its active site contains one accessible and one buried cysteine residue, Cys30 and Cys33, respectively, which can form a very unstable disulfide bond between them that is 10(3)-fold more reactive toward thiol groups than normal. The two cysteine residues have normal properties when in a short peptide. In DsbA, the Cys30 thiol group is shown to be reactive toward alkylating reagents down to pH 4 and to be fully ionized, on the basis of the UV absorbance of the thiolate anion at 240 nm. Its reactivity is altered by another, unknown group on the reduced protein titrating with a pKa of about 6.7. The other cysteine residue is buried and unreactive and has a high pKa value. The ionization properties of the DsbA thiol groups can explain, at least partly, the high reactivity of its disulfide bonds and thiol groups at both neutral and acidic pH values.
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Affiliation(s)
- J W Nelson
- European Molecular Biology Laboratory, Heidelberg, Germany
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