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Hohos NM, Smith AK, Kilaru V, Park HJ, Hausman DB, Bailey LB, Lewis RD, Phillips BG, Meagher RB. CD4 + and CD8 + T-Cell-Specific DNA Cytosine Methylation Differences Associated With Obesity. Obesity (Silver Spring) 2018; 26:1312-1321. [PMID: 29956501 PMCID: PMC6107382 DOI: 10.1002/oby.22225] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 05/13/2018] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Lifestyle factors associated with obesity may alter epigenome-regulated gene expression. Most studies examining epigenetic changes in obesity have analyzed DNA 5´-methylcytosine (5mC) in whole blood, representing a weighted average of several distantly related and regulated leukocyte classes. To examine leukocyte-specific differences associated with obesity, a pilot study examining 5mC in three distinct leukocyte types isolated from peripheral blood of women with normal weight and obesity was conducted. METHODS CD4+ T cells, CD8+ T cells, and CD16+ neutrophils were reiteratively isolated from blood, and 5mC levels were measured across >450,000 CG sites. RESULTS Nineteen CG sites were differentially methylated between women with obesity and with normal weight in CD4+ cells, 16 CG sites in CD8+ cells, and 0 CG sites in CD16+ neutrophils (q < 0.05). There were no common differentially methylated sites between the T-cell types. The amount of visceral adipose tissue was strongly associated with the methylation level of 79 CG sites in CD4+ cells, including 4 CG sites in CLSTN1's promoter, which, this study shows, may regulate its expression. CONCLUSIONS The methylomes of various leukocytes respond differently to obesity and levels of visceral adipose tissue. Highly significant differentially methylated sites in CD4+ and CD8+ cells in women with obesity that have apparent biological relevance to obesity were identified.
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Affiliation(s)
- Natalie M Hohos
- Department of Foods and Nutrition, University of Georgia, Athens, GA, USA
- Corresponding Author: 120 Green Street, University of Georgia, Athens, GA 30602-7223
| | - Alicia K Smith
- Physciatry and Behavioral Sciences, University of Emory School of Medicine, Atlanta, GA, USA
| | - Varun Kilaru
- Physciatry and Behavioral Sciences, University of Emory School of Medicine, Atlanta, GA, USA
| | - Hea Jin Park
- Department of Foods and Nutrition, University of Georgia, Athens, GA, USA
| | - Dorothy B Hausman
- Department of Foods and Nutrition, University of Georgia, Athens, GA, USA
| | - Lynn B Bailey
- Department of Foods and Nutrition, University of Georgia, Athens, GA, USA
| | - Richard D Lewis
- Department of Foods and Nutrition, University of Georgia, Athens, GA, USA
| | - Bradley G Phillips
- Clinical and Administrative Pharmacy, University of Georgia, Athens, GA, USA
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Hou R, Alemozaffar M, Yang B, Sands JM, Kong X, Chen G. Identification of a Novel UT-B Urea Transporter in Human Urothelial Cancer. Front Physiol 2017; 8:245. [PMID: 28503151 PMCID: PMC5409228 DOI: 10.3389/fphys.2017.00245] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 04/07/2017] [Indexed: 02/01/2023] Open
Abstract
The urea transporter UT-B is widely expressed and has been studied in erythrocyte, kidney, brain and intestines. Interestingly, UT-B gene has been found more abundant in bladder than any other tissue. Recently, gene analyses demonstrate that SLC14A1 (UT-B) gene mutations are associated with bladder cancer, suggesting that urea transporter UT-B may play an important role in bladder carcinogenesis. In this study, we examined UT-B expression in bladder cancer with human primary bladder cancer tissues and cancer derived cell lines. Human UT-B has two isoforms. We found that normal bladder expresses long form of UT-B2 but was lost in 8 of 24 (33%) or significantly downregulated in 16 of 24 (67%) of primary bladder cancer patients. In contrast, the short form of UT-B1 lacking exon 3 was detected in 20 bladder cancer samples. Surprisingly, a 24-nt in-frame deletion in exon 4 in UT-B1 (UT-B1Δ24) was identified in 11 of 20 (55%) bladder tumors. This deletion caused a functional defect of UT-B1. Immunohistochemistry revealed that UT-B protein levels were significantly decreased in bladder cancers. Western blot analysis showed a weak UT-B band of 40 kDa in some tumors, consistent with UT-B1 gene expression detected by RT-PCR. Interestingly, bladder cancer associate UT-B1Δ24 was barely sialylated, reflecting impaired glycosylation of UT-B1 in bladder tumors. In conclusion, SLC14A1 gene and UT-B protein expression are significantly changed in bladder cancers. The aberrant UT-B expression may promote bladder cancer development or facilitate carcinogenesis induced by other carcinogens.
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Affiliation(s)
- Ruida Hou
- Department of Urology, China-Japan Union Hospital, Jilin UniversityChangchun, China.,Department of Physiology, Emory University School of MedicineAtlanta, GA, USA
| | | | - Baoxue Yang
- Department of Pharmacology, School of Basic Medical Sciences, Peking UniversityBeijing, China
| | - Jeff M Sands
- Department of Physiology, Emory University School of MedicineAtlanta, GA, USA.,Renal Division Department of Medicine, Emory University School of MedicineAtlanta, GA, USA
| | - Xiangbo Kong
- Department of Urology, China-Japan Union Hospital, Jilin UniversityChangchun, China
| | - Guangping Chen
- Department of Physiology, Emory University School of MedicineAtlanta, GA, USA.,Renal Division Department of Medicine, Emory University School of MedicineAtlanta, GA, USA
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Qian X, Li X, Ilori TO, Klein JD, Hughey RP, Li CJ, Alli AA, Guo Z, Yu P, Song X, Chen G. RNA-seq analysis of glycosylation related gene expression in STZ-induced diabetic rat kidney inner medulla. Front Physiol 2015; 6:274. [PMID: 26483702 PMCID: PMC4590316 DOI: 10.3389/fphys.2015.00274] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 09/17/2015] [Indexed: 12/30/2022] Open
Abstract
The UT-A1 urea transporter is crucial to the kidney's ability to generate concentrated urine. Native UT-A1 from kidney inner medulla (IM) is a heavily glycosylated protein with two glycosylation forms of 97 and 117 kDa. In diabetes, UT-A1 protein abundance, particularly the 117 kD isoform, is significantly increased corresponding to an increased urea permeability in perfused IM collecting ducts, which plays an important role in preventing the osmotic diuresis caused by glucosuria. However, how the glycan carbohydrate structure change and the glycan related enzymes regulate kidney urea transport activity, particularly under diabetic condition, is largely unknown. In this study, using sugar-specific binding lectins, we found that the carbohydrate structure of UT-A1 is changed with increased amounts of sialic acid, fucose, and increased glycan branching under diabetic conditions. These changes were accompanied by altered UT-A1 association with the galectin proteins, β-galactoside glycan binding proteins. To explore the molecular basis of the alterations of glycan structures, the highly sensitive next generation sequencing (NGS) technology, Illumina RNA-seq, was employed to analyze genes involved in the process of UT-A1 glycosylation using streptozotocin (STZ)—induced diabetic rat kidney. Differential gene expression analysis combining with quantitative PCR revealed that expression of a number of important glycosylation related genes were changed under diabetic conditions. These genes include the glycosyltransferase genes Mgat4a, the sialylation enzymes St3gal1 and St3gal4 and glycan binding protein galectin-3, -5, -8, and -9. In contrast, although highly expressed in kidney IM, the glycosyltransferase genes Mgat1, Mgat2, and fucosyltransferase Fut8, did not show any changes. Conclusions: In diabetes, not only is UT-A1 protein abundance increased but the protein's glycan structure is also significantly changed. UT-A1 protein becomes highly sialylated, fucosylated and branched. Consistently, a number of crucial glycosylation related genes are changed under diabetic conditions. The alteration of these genes may contribute to changes in the UT-A1 glycan structure and therefore modulate kidney urea transport activity and alleviate osmotic diuresis caused by glucosuria in diabetes.
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Affiliation(s)
- Xiaoqian Qian
- Department of Physiology, Emory University School of Medicine Atlanta, GA, USA ; Department of Cardiology, The Fourth Affiliated Hospital of Harbin Medical University Harbin, China
| | - Xuechen Li
- Department of Physiology, Emory University School of Medicine Atlanta, GA, USA
| | - Titilayo O Ilori
- Renal Division, Department of Medicine, Emory University School of Medicine Atlanta, GA, USA
| | - Janet D Klein
- Department of Physiology, Emory University School of Medicine Atlanta, GA, USA ; Renal Division, Department of Medicine, Emory University School of Medicine Atlanta, GA, USA
| | - Rebecca P Hughey
- Renal-Electrolyte Division and Department of Cell Biology and Physiology, Department of Medicine, University of Pittsburgh School of Medicine Pittsburgh, PA, USA
| | - Cong-Jun Li
- Bovine Functional Genomics Laboratory, United States Department of Agriculture - Agricultural Research Service Beltsville, MD, USA
| | - Abdel A Alli
- Department of Physiology, Emory University School of Medicine Atlanta, GA, USA
| | - Zhengyu Guo
- Department of Electrical and Computer Engineering, TEES-AgriLife Center for Bioinformatics and Genomic Systems Engineering, Texas A&M University College Station, TX, USA
| | - Peng Yu
- Department of Electrical and Computer Engineering, TEES-AgriLife Center for Bioinformatics and Genomic Systems Engineering, Texas A&M University College Station, TX, USA
| | - Xiang Song
- Department of Cardiology, The Fourth Affiliated Hospital of Harbin Medical University Harbin, China
| | - Guangping Chen
- Department of Physiology, Emory University School of Medicine Atlanta, GA, USA ; Renal Division, Department of Medicine, Emory University School of Medicine Atlanta, GA, USA
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Abstract
Some unicellular organisms can take up urea from the surrounding fluids by an uphill pumping mechanism. Several active (energy-dependent) urea transporters (AUTs) have been cloned in these organisms. Functional studies show that active urea transport also occurs in elasmobranchs, amphibians, and mammals. In the two former groups, active urea transport may serve to conserve urea in body fluids in order to balance external high ambient osmolarity or prevent desiccation. In mammals, active urea transport may be associated with the need to either store and/or reuse nitrogen in the case of low nitrogen supply, or to excrete nitrogen efficiently in the case of excess nitrogen intake. There are probably two different families of AUTs, one with a high capacity able to establish only a relatively modest transepithelial concentration difference (renal tubule of some frogs, pars recta of the mammalian kidney, early inner medullary collecting duct in some mammals eating protein-poor diets) and others with a low capacity but able to maintain a high transepithelial concentration difference that has been created by another mechanism or in another organ (elasmobranch gills, ventral skin of some toads, and maybe mammalian urinary bladder). Functional characterization of these transporters shows that some are coupled to sodium (symports or antiports) while others are sodium-independent. In humans, only one genetic anomaly, with a mild phenotype (familial azotemia), is suspected to concern one of these transporters. In spite of abundant functional evidence for such transporters in higher organisms, none have been molecularly identified yet.
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Affiliation(s)
- Lise Bankir
- INSERM UMRS 1138, Centre de Recherche Des Cordeliers, Paris, France,
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Abstract
Urea transport proteins were initially proposed to exist in the kidney in the late 1980s when studies of urea permeability revealed values in excess of those predicted by simple lipid-phase diffusion and paracellular transport. Less than a decade later, the first urea transporter was cloned. Currently, the SLC14A family of urea transporters contains two major subgroups: SLC14A1, the UT-B urea transporter originally isolated from erythrocytes; and SLC14A2, the UT-A group with six distinct isoforms described to date. In the kidney, UT-A1 and UT-A3 are found in the inner medullary collecting duct; UT-A2 is located in the thin descending limb, and UT-B is located primarily in the descending vasa recta; all are glycoproteins. These transporters are crucial to the kidney's ability to concentrate urine. UT-A1 and UT-A3 are acutely regulated by vasopressin. UT-A1 has also been shown to be regulated by hypertonicity, angiotensin II, and oxytocin. Acute regulation of these transporters is through phosphorylation. Both UT-A1 and UT-A3 rapidly accumulate in the plasma membrane in response to stimulation by vasopressin or hypertonicity. Long-term regulation involves altering protein abundance in response to changes in hydration status, low protein diets, adrenal steroids, sustained diuresis, or antidiuresis. Urea transporters have been studied using animal models of disease including diabetes mellitus, lithium intoxication, hypertension, and nephrotoxic drug responses. Exciting new animal models are being developed to study these transporters and search for active urea transporters. Here we introduce urea and describe the current knowledge of the urea transporter proteins, their regulation, and their role in the kidney.
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Affiliation(s)
- Janet D Klein
- Renal Division, Department of Medicine, Emory University, Atlanta, Georgia, USA
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