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da Silva MI, Ott T. Effects of conceptus proteins on endometrium and blood leukocytes of dairy cattle using transcriptome and meta-analysis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.25.591148. [PMID: 38712302 PMCID: PMC11071483 DOI: 10.1101/2024.04.25.591148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
This study investigates the short and long-term effects of IFNT and PAG on the transcriptome of endometrium and blood leukocytes. Holstein heifers received intrauterine infusions of one of the following treatments: 20 mL of a 200 μg/mL bovine serum albumin solution (BSA; vehicle) from day 14 to 16 of the estrous cycle (BSA), vehicle + 10 μg/mL of IFNT from day 14 to 16 (IFNT3), vehicle + 10 μg/mL of IFNT from day 14 to 19 (IFNT6), and vehicle + 10 μg/mL of IFNT from day 14 to 16 followed by vehicle + 10 μg/mL of IFNT + 5 μg/mL of PAG from day 17 to 19 (IFNT+PAG). RNA-seq analysis was performed in endometrial biopsies and blood leukocytes collected after treatments. Acute IFNT signaling in the endometrium (IFNT3 vs BSA), induced differentially expressed genes (DEG) associated with interferon activation, immune response, inflammation, cell death, and inhibited vesicle transport and extracellular matrix remodeling. Prolonged IFNT signaling (IFNT6 vs IFNT3) altered gene expression related to cell invasion, retinoic acid signaling, and embryo implantation. In contrast, PAG induced numerous DEG in blood leukocytes but only 4 DEG in the endometrium. In blood leukocytes, PAG stimulated genes involved in development and TGFB signaling while inhibiting interferon signaling and cell migration. Overall, IFNT is a primary regulator of endometrial gene expression, while PAG predominantly affected the transcriptome of circulating immune cells during early pregnancy. Further research is essential to fully grasp the roles of identified DEG in both the endometrium and blood leukocytes.
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Affiliation(s)
- Maria Isabel da Silva
- Department of Animal Science, Center for Reproductive Biology and Health, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, USA
| | - Troy Ott
- Department of Animal Science, Center for Reproductive Biology and Health, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, USA
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Takano-Kawabe K, Matoba K, Nakamura Y, Moriyama M. Low Density Lipoprotein Receptor-related Protein 2 Expression and Function in Cultured Astrocytes and Microglia. Neurochem Res 2024; 49:199-211. [PMID: 37702891 DOI: 10.1007/s11064-023-04022-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 08/23/2023] [Accepted: 08/28/2023] [Indexed: 09/14/2023]
Abstract
Activation of glial cells, astrocytes and microglia, has been observed in neurodegenerative diseases including Alzheimer's disease (AD). Amyloid β (Aβ), which is aggregated and the aggregation is detected as characteristic pathology in AD brain, is known to be produced by neurons and to activate glial cells. Clearance of Aβ from the brain via active transport system is important to prevent the accumulation and aggregation. Low density lipoprotein receptor-related protein 2 (LRP2/megalin) is an Aβ transporter. However, expression and contribution of LRP2 in astrocytes and microglia remain to be clarified. In the present study, we examined the expression of LRP2 and its roles in cultured astrocytes prepared from rat embryonic brain cortex and mouse microglial cell line BV-2. Both cultured rat astrocytes and BV-2 cells expressed LRP2 mRNA detected by RT-PCR. When lipopolysaccharide (LPS) or all-trans retinoic acid (ATRA) were added to BV-2 cells, LRP2 mRNA expression and uptake of microbeads, Aβ and insulin were increased. On the other hand, LPS decreased LRP2 expression and uptake of Aβ and insulin in cultured astrocytes. Knockdown of LRP2 using siRNA attenuated the LPS- or ATRA-increased uptake of microbeads, Aβ and insulin in BV-2 cells. These results suggest that LRP2 was expressed in both astrocytes and microglia and might be involved in endocytosis activities. Adequate control of LRP2 expression and function in astrocytes and microglia might regulate Aβ and insulin levels in brain and would be a potential target in AD pathology.
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Affiliation(s)
- Katsura Takano-Kawabe
- Laboratory of Integrative Physiology in Veterinary Sciences, Osaka Metropolitan University, 1-58, Rinku-Ourai Kita, Izumisano, Osaka, 598-8531, Japan.
| | - Kazuyuki Matoba
- Laboratory of Integrative Physiology in Veterinary Sciences, Osaka Metropolitan University, 1-58, Rinku-Ourai Kita, Izumisano, Osaka, 598-8531, Japan
| | - Yoichi Nakamura
- Laboratory of Integrative Physiology in Veterinary Sciences, Osaka Metropolitan University, 1-58, Rinku-Ourai Kita, Izumisano, Osaka, 598-8531, Japan
| | - Mitsuaki Moriyama
- Laboratory of Integrative Physiology in Veterinary Sciences, Osaka Metropolitan University, 1-58, Rinku-Ourai Kita, Izumisano, Osaka, 598-8531, Japan
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Alberro-Brage A, Kryvenko V, Malainou C, Günther S, Morty RE, Seeger W, Herold S, Samakovlis C, Vadász I. Influenza virus decreases albumin uptake and megalin expression in alveolar epithelial cells. Front Immunol 2023; 14:1260973. [PMID: 37727782 PMCID: PMC10505651 DOI: 10.3389/fimmu.2023.1260973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 08/17/2023] [Indexed: 09/21/2023] Open
Abstract
Introduction Acute respiratory distress syndrome (ARDS) is a common complication of influenza virus (IV) infection. During ARDS, alveolar protein concentrations often reach 40-90% of plasma levels, causing severe impairment of gas exchange and promoting deleterious alveolar remodeling. Protein clearance from the alveolar space is at least in part facilitated by the multi-ligand receptor megalin through clathrin-mediated endocytosis. Methods To investigate whether IV infection impairs alveolar protein clearance, we examined albumin uptake and megalin expression in MLE-12 cells and alveolar epithelial cells (AEC) from murine precision-cut lung slices (PCLS) and in vivo, under IV infection conditions by flow cytometry and western blot. Transcriptional levels from AEC and broncho-alveolar lavage (BAL) cells were analyzed in an in-vivo mouse model by RNAseq. Results IV significantly downregulated albumin uptake, independently of activation of the TGF-β1/GSK3β axis that has been previously implicated in the regulation of megalin function. Decreased plasma membrane abundance, total protein levels, and mRNA expression of megalin were associated with this phenotype. In IV-infected mice, we identified a significant upregulation of matrix metalloproteinase (MMP)-14 in BAL fluid cells. Furthermore, the inhibition of this protease partially recovered total megalin levels and albumin uptake. Discussion Our results suggest that the previously described MMP-driven shedding mechanisms are potentially involved in downregulation of megalin cell surface abundance and clearance of excess alveolar protein. As lower alveolar edema protein concentrations are associated with better outcomes in respiratory failure, our findings highlight the therapeutic potential of a timely MMP inhibition in the treatment of IV-induced ARDS.
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Affiliation(s)
- Andrés Alberro-Brage
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany
- German Center for Lung Research (DZL), Giessen, Germany
- The Cardio-Pulmonary Institute (CPI), Giessen, Germany
- Institute for Lung Health (ILH), Giessen, Germany
| | - Vitalii Kryvenko
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany
- German Center for Lung Research (DZL), Giessen, Germany
- The Cardio-Pulmonary Institute (CPI), Giessen, Germany
- Institute for Lung Health (ILH), Giessen, Germany
| | - Christina Malainou
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany
- German Center for Lung Research (DZL), Giessen, Germany
- The Cardio-Pulmonary Institute (CPI), Giessen, Germany
- Institute for Lung Health (ILH), Giessen, Germany
| | - Stefan Günther
- Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Rory E. Morty
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany
- German Center for Lung Research (DZL), Giessen, Germany
- The Cardio-Pulmonary Institute (CPI), Giessen, Germany
- Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
- Department of Translational Pulmonology, Heidelberg University Hospital, Heidelberg, Germany
| | - Werner Seeger
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany
- German Center for Lung Research (DZL), Giessen, Germany
- The Cardio-Pulmonary Institute (CPI), Giessen, Germany
- Institute for Lung Health (ILH), Giessen, Germany
- Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Susanne Herold
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany
- German Center for Lung Research (DZL), Giessen, Germany
- The Cardio-Pulmonary Institute (CPI), Giessen, Germany
- Institute for Lung Health (ILH), Giessen, Germany
| | - Christos Samakovlis
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany
- German Center for Lung Research (DZL), Giessen, Germany
- The Cardio-Pulmonary Institute (CPI), Giessen, Germany
- Institute for Lung Health (ILH), Giessen, Germany
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - István Vadász
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany
- German Center for Lung Research (DZL), Giessen, Germany
- The Cardio-Pulmonary Institute (CPI), Giessen, Germany
- Institute for Lung Health (ILH), Giessen, Germany
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Barta P, Nachtigal P, Maixnerova J, Zemankova L, Trejtnar F. Validation of Freshly Isolated Rat Renal Cells as a Tool for Preclinical Assessment of Radiolabeled Receptor-Specific Peptide Uptake in the Kidney. Pharmaceuticals (Basel) 2023; 16:ph16050696. [PMID: 37242479 DOI: 10.3390/ph16050696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/19/2023] [Accepted: 05/02/2023] [Indexed: 05/28/2023] Open
Abstract
The synthetic analogs of regulatory peptides radiolabeled with adequate radionuclides are perspective tools in nuclear medicine. However, undesirable uptake and retention in the kidney limit their application. Specific in vitro methods are used to evaluate undesirable renal accumulation. Therefore, we investigated the usefulness of freshly isolated rat renal cells for evaluating renal cellular uptake of receptor-specific peptide analogs. Special attention was given to megalin as this transport system is an important contributor to the active renal uptake of the peptides. Freshly isolated renal cells were obtained from native rat kidneys by the collagenase method. Compounds with known accumulation in renal cells were used to verify the viability of cellular transport systems. Megalin expressions in isolated rat renal cells were compared to two other potential renal cell models by Western blotting. Specific tubular cell markers were used to confirm the presence of proximal tubular cells expressing megalin in isolated rat renal cell preparations by immunohistochemistry. Colocalization experiments on isolated rat kidney cells confirmed the presence of proximal tubular cells bearing megalin in preparations. The applicability of the method was tested by an accumulation study with several analogs of somatostatin and gastrin labeled with indium-111 or lutetium-177. Therefore, isolated rat renal cells may be an effective screening tool for in vitro analyses of renal uptake and comparative renal accumulation studies of radiolabeled peptides or other radiolabeled compounds with potential nephrotoxicity.
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Affiliation(s)
- Pavel Barta
- Department of Biophysics and Physical Chemistry, Faculty of Pharmacy in Hradec Kralové, Charles University, Akademika Heyrovskeho 1203, 50005 Hradec Kralove, Czech Republic
| | - Petr Nachtigal
- Department of Biological and Medical Sciences, Faculty of Pharmacy in Hradec Kralové, Charles University, Akademika Heyrovskeho 1203, 50005 Hradec Kralove, Czech Republic
| | - Jana Maixnerova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralové, Charles University, Akademika Heyrovskeho 1203, 50005 Hradec Kralove, Czech Republic
| | - Lenka Zemankova
- Department of Cell Biology and Genetics, Faculty of Science, Palacky University, Slechtitelu 27, 78371 Olomouc, Czech Republic
| | - Frantisek Trejtnar
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralové, Charles University, Akademika Heyrovskeho 1203, 50005 Hradec Kralove, Czech Republic
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Bagheri A, Radman G, Aria N, Rezaei F, Khajenouri M, Ghiabi S, Bagheri Y. The Effects of Quercetin on Apoptosis and Antioxidant Activity in a Renal Ischemia/Reperfusion Injury Animal Model. Drug Res (Stuttg) 2023. [PMID: 36972618 DOI: 10.1055/a-1999-7600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
Renal ischemia-reperfusion injury (IRI) is considered as one of the most prevalent causes of acute kidney injury (AKI), which can happen in various clinical situations including hypovolemic shock, injury, thrombo-embolism, and after a kidney transplant. This paper aims to evaluate the reno-protective effects of Quercetin in induced ischemia/reperfusion injury by regulating apoptosis-related proteins, inflammatory cytokines, MMP-2, MMP-9, and nuclear factor kappa-light-chain-enhancer inactivated B cells (NF-kB) in rats. The male Wistar rats (n=32) were randomly divided into Sham, untreated IR, and Quercetin-treated IR (gavage and intraperitoneal). Quercetin was given orally and intraperitoneally one hour before inducing ischemia-reperfusion injury . After reperfusion, blood samples and kidneys were collected to assess renal function and inflammatory cytokines, apoptotic signaling proteins, and antioxidants. Urea, creatinine, and MDA levels improved in Quercetin-treated groups with different administration methods. In addition, the activities of other antioxidant in Quercetin-treated rats were higher than those in the IR group. Further, Quercetin inhibited NF-kB signaling, apoptosis-associated factors and produced matrix metalloproteinase protein in the kidneys of rats. Based on the findings, the antioxidant, anti-inflammatory, and anti-apoptotic effects of the Quercetin diminished renal ischemia-reperfusion injury in the rats significantly. It is suggested that a single dosage of Quercetin have a reno-protective impact in the case of renal I/R injury.
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Affiliation(s)
- Amin Bagheri
- Department of Urology, Sina Hospital, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ghazal Radman
- Molecular Medicine Research Center, Hormozgan Health Institute, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
- Network of Immunity in Infection, Malignancy and Autoimmunity (NIIMA), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Negar Aria
- Department of Microbiology, School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Fatemeh Rezaei
- Faculty of Pharmacy in Hradec Kralove, Charles University, Prague, Czech Republic
| | - Mohammad Khajenouri
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Shamim Ghiabi
- Department of Medical Chemistry, Faculty of Pharmacy, Tehran Medical Sciences Islamic Azad University, Tehran, Iran
| | - Yasin Bagheri
- Kidney Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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Nemeth Z, Patonai A, Simon-Szabó L, Takács I. Interplay of Vitamin D and SIRT1 in Tissue-Specific Metabolism-Potential Roles in Prevention and Treatment of Non-Communicable Diseases Including Cancer. Int J Mol Sci 2023; 24:ijms24076154. [PMID: 37047134 PMCID: PMC10094444 DOI: 10.3390/ijms24076154] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/13/2023] [Accepted: 03/16/2023] [Indexed: 04/14/2023] Open
Abstract
The importance of the prevention and control of non-communicable diseases, including obesity, metabolic syndrome, type 2 diabetes, cardiovascular diseases, and cancer, is increasing as a requirement of the aging population in developed countries and the sustainability of healthcare. Similarly, the 2013-2030 action plan of the WHO for the prevention and control of non-communicable diseases seeks these achievements. Adequate lifestyle changes, alone or with the necessary treatments, could reduce the risk of mortality or the deterioration of quality of life. In our recent work, we summarized the role of two central factors, i.e., appropriate levels of vitamin D and SIRT1, which are connected to adequate lifestyles with beneficial effects on the prevention and control of non-communicable diseases. Both of these factors have received increased attention in relation to the COVID-19 pandemic as they both take part in regulation of the main metabolic processes, i.e., lipid/glucose/energy homeostasis, oxidative stress, redox balance, and cell fate, as well as in the healthy regulation of the immune system. Vitamin D and SIRT1 have direct and indirect influence of the regulation of transcription and epigenetic changes and are related to cytoplasmic signaling pathways such as PLC/DAG/IP3/PKC/MAPK, MEK/Erk, insulin/mTOR/cell growth, proliferation; leptin/PI3K-Akt-mTORC1, Akt/NFĸB/COX-2, NFĸB/TNFα, IL-6, IL-8, IL-1β, and AMPK/PGC-1α/GLUT4, among others. Through their proper regulation, they maintain normal body weight, lipid profile, insulin secretion and sensitivity, balance between the pro- and anti-inflammatory processes under normal conditions and infections, maintain endothelial health; balance cell differentiation, proliferation, and fate; and balance the circadian rhythm of the cellular metabolism. The role of these two molecules is interconnected in the molecular network, and they regulate each other in several layers of the homeostasis of energy and the cellular metabolism. Both have a central role in the maintenance of healthy and balanced immune regulation and redox reactions; therefore, they could constitute promising targets either for prevention or as complementary therapies to achieve a better quality of life, at any age, for healthy people and patients under chronic conditions.
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Affiliation(s)
- Zsuzsanna Nemeth
- Department of Internal Medicine and Oncology, Semmelweis University, Koranyi S. u 2/a, 1083 Budapest, Hungary
| | - Attila Patonai
- Department of Surgery, Transplantation and Gastroenterology, Semmelweis University, Ulloi u. 78, 1082 Budapest, Hungary
| | - Laura Simon-Szabó
- Department of Molecular Biology, Semmelweis University, Tuzolto u. 37-47, 1094 Budapest, Hungary
| | - István Takács
- Department of Internal Medicine and Oncology, Semmelweis University, Koranyi S. u 2/a, 1083 Budapest, Hungary
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Megalin and Vitamin D Metabolism—Implications in Non-Renal Tissues and Kidney Disease. Nutrients 2022; 14:nu14183690. [PMID: 36145066 PMCID: PMC9506339 DOI: 10.3390/nu14183690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/02/2022] [Accepted: 09/06/2022] [Indexed: 11/17/2022] Open
Abstract
Megalin is an endocytic receptor abundantly expressed in proximal tubular epithelial cells and other calciotropic extrarenal cells expressing vitamin D metabolizing enzymes, such as bone and parathyroid cells. The receptor functions in the uptake of the vitamin D-binding protein (DBP) complexed to 25 hydroxyvitamin D3 (25(OH)D3), facilitating the intracellular conversion of precursor 25(OH)D3 to the active 1,25 dihydroxyvitamin D3 (1,25(OH)2D3). The significance of renal megalin-mediated reabsorption of 25(OH)D3 and 1,25(OH)2D3 has been well established experimentally, and other studies have demonstrated relevant roles of extrarenal megalin in regulating vitamin D homeostasis in mammary cells, fat, muscle, bone, and mesenchymal stem cells. Parathyroid gland megalin may regulate calcium signaling, suggesting intriguing possibilities for megalin-mediated cross-talk between calcium and vitamin D regulation in the parathyroid; however, parathyroid megalin functionality has not been assessed in the context of vitamin D. Within various models of chronic kidney disease (CKD), megalin expression appears to be downregulated; however, contradictory results have been observed between human and rodent models. This review aims to provide an overview of the current knowledge of megalin function in the context of vitamin D metabolism, with an emphasis on extrarenal megalin, an area that clearly requires further investigation.
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O’Connor C, Varshosaz P, Moise AR. Mechanisms of Feedback Regulation of Vitamin A Metabolism. Nutrients 2022; 14:nu14061312. [PMID: 35334970 PMCID: PMC8950952 DOI: 10.3390/nu14061312] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 02/06/2023] Open
Abstract
Vitamin A is an essential nutrient required throughout life. Through its various metabolites, vitamin A sustains fetal development, immunity, vision, and the maintenance, regulation, and repair of adult tissues. Abnormal tissue levels of the vitamin A metabolite, retinoic acid, can result in detrimental effects which can include congenital defects, immune deficiencies, proliferative defects, and toxicity. For this reason, intricate feedback mechanisms have evolved to allow tissues to generate appropriate levels of active retinoid metabolites despite variations in the level and format, or in the absorption and conversion efficiency of dietary vitamin A precursors. Here, we review basic mechanisms that govern vitamin A signaling and metabolism, and we focus on retinoic acid-controlled feedback mechanisms that contribute to vitamin A homeostasis. Several approaches to investigate mechanistic details of the vitamin A homeostatic regulation using genomic, gene editing, and chromatin capture technologies are also discussed.
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Affiliation(s)
- Catherine O’Connor
- MD Program, Northern Ontario School of Medicine, 317-MSE Bldg., 935 Ramsey Lake Rd., Sudbury, ON P3E 2C6, Canada;
| | - Parisa Varshosaz
- Biology and Biomolecular Sciences Ph.D. Program, Northern Ontario School of Medicine, Laurentian University, Sudbury, ON P3E 2C6, Canada;
| | - Alexander R. Moise
- Medical Sciences Division, Northern Ontario School of Medicine, 317-MSE Bldg., 935 Ramsey Lake Rd., Sudbury, ON P3E 2C6, Canada
- Department of Chemistry and Biochemistry, Biology and Biomolecular Sciences Program, Laurentian University, Sudbury, ON P3E 2C6, Canada
- Correspondence: ; Tel.: +1-705-662-7253
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Dusso AS, Bauerle KT, Bernal-Mizrachi C. Non-classical Vitamin D Actions for Renal Protection. Front Med (Lausanne) 2021; 8:790513. [PMID: 34950686 PMCID: PMC8688743 DOI: 10.3389/fmed.2021.790513] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 11/15/2021] [Indexed: 11/17/2022] Open
Abstract
Chronic Kidney Disease (CKD), a disorder that affects 11% of the world's population, is characterized by an acceleration in skeletal, immune, renal, and cardiovascular aging that increases the risk of cardiovascular mortality by 10- to 20-fold, compared to that in individuals with normal renal function. For more than two decades, the progressive impairment in renal capacity to maintain normal circulating levels of the hormonal form of vitamin D (1,25-dihydroxyvitamin D or calcitriol) was considered the main contributor to the reduced survival of CKD patients. Accordingly, calcitriol administration was the treatment of choice to attenuate the progression of secondary hyperparathyroidism (SHPT) and its adverse impact on bone health and vascular calcification. The development of calcitriol analogs, designed to mitigate the resistance to calcitriol suppression of PTH associated with CKD progression, demonstrated survival benefits unrelated to the control of SHPT or skeletal health. The exhaustive search for the pathophysiology behind survival benefits associated with active vitamin D analogs has identified novel anti-inflammatory, anti-hypertensive, anti-aging actions of the vitamin D endocrine system. A major paradigm shift regarding the use of calcitriol or active vitamin D analogs to improve survival in CKD patients emerged upon demonstration of a high prevalence of vitamin D (not calcitriol) deficiency at all stages of CKD and, more significantly, that maintaining serum levels of the calcitriol precursor, 25(OH)vitamin D, above 23 ng/ml delayed CKD progression. The cause of vitamin D deficiency in CKD, however, is unclear since vitamin D bioactivation to 25(OH)D occurs mostly at the liver. Importantly, neither calcitriol nor its analogs can correct vitamin D deficiency. The goals of this chapter are to present our current understanding of the pathogenesis of vitamin D deficiency in CKD and of the causal link between defective vitamin D bioactivation to calcitriol and the onset of molecular pathways that promote CKD progression independently of the degree of SHPT. An understanding of these mechanisms will highlight the need for identification of novel sensitive biomarkers to assess the efficacy of interventions with vitamin D and/or calcitriol(analogs) to ameliorate CKD progression in a PTH-independent manner.
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Affiliation(s)
- Adriana S. Dusso
- Division of Endocrinology, Metabolism and Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Kevin T. Bauerle
- Division of Endocrinology, Metabolism and Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
- Department of Medicine, VA Medical Center, St. Louis, MO, United States
| | - Carlos Bernal-Mizrachi
- Division of Endocrinology, Metabolism and Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
- Department of Medicine, VA Medical Center, St. Louis, MO, United States
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, United States
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Trdin A, Snoj Tratnik J, Stajnko A, Marc J, Mazej D, Sešek Briški A, Kastelec D, Prpić I, Petrović O, Špirić Z, Horvat M, Falnoga I. Trace elements and APOE polymorphisms in pregnant women and their new-borns. ENVIRONMENT INTERNATIONAL 2020; 143:105626. [PMID: 32622117 DOI: 10.1016/j.envint.2020.105626] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 02/28/2020] [Accepted: 02/29/2020] [Indexed: 06/11/2023]
Abstract
We investigated the relationship between lipid binding glycoprotein apolipoprotein E (apoE; gene APOE) polymorphisms (ε4 allele carriers versus no carriers = ε4+/ε4-) and trace elements (TEs) (e.g., (methyl)mercury, arsenic, lead, cadmium, selenium, manganese, copper, and zinc) in mothers (N = 223) and their new-borns (N = 213) exposed to potentially toxic metal(loid)s from seafood consumption. The apoE isoform encoded by the ε4 allele is believed to have beneficial effects in early life but represents a risk factor for age-associated diseases. Under certain conditions ε4 carriers are more susceptible to oxidative stress and metal(loid) toxicity. DNA from Croatian pregnant women (N = 223, third trimester) and their new-borns (N = 176), was genotyped for APOE by TaqMan® SNP assay - rs429358 and rs7412. Seafood intake data and TE levels in maternal urine, milk, hair, peripheral venous blood, mixed cord blood, and new-borns' urine were available from previous studies. We compared TEs between ε4+ and ε4- carriers using Mann-Whitney U tests and applied multiple linear regression models to analyse the TE's dependence on the presence of allele ε4 (genotypes ε3/ε4, ε4/ε4) in combination with other explanatory variables. We identified 17% (n = 37) and 20% (n = 35) ε4 allele carriers in mothers and new-borns, respectively. The Mann-Whitney U test showed that mothers with the ε4 allele had significantly higher mean levels of (methyl)mercury in peripheral venous blood, cord blood, and hair; arsenic in urine and cord blood; and selenium in peripheral venous blood and plasma. However, taking confounders into account, only the maternal plasma selenium remained statistically significant in the linear regression models (ε4 carriers vs non-carriers: 62.6 vs 54.9 ng/mL, p < 0.001). Literature suggestions of possible ε4 allele impact on Hg levels were not observed, while superior selenium status observed in healthy pregnant women carrying allele ε4 could be linked to the proposed APOE ε4 beneficial effects early in life.
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Affiliation(s)
- Ajda Trdin
- Department of Environmental Sciences, Jožef Stefan Institute, Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Janja Snoj Tratnik
- Department of Environmental Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Anja Stajnko
- Department of Environmental Sciences, Jožef Stefan Institute, Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Janja Marc
- Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
| | - Darja Mazej
- Department of Environmental Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Alenka Sešek Briški
- Institute of Clinical Chemistry and Biochemistry, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | | | - Igor Prpić
- Department of Paediatrics, University Hospital Centre Rijeka, Rijeka, Croatia; Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Oleg Petrović
- Department of Paediatrics, University Hospital Centre Rijeka, Rijeka, Croatia
| | | | - Milena Horvat
- Department of Environmental Sciences, Jožef Stefan Institute, Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Ingrid Falnoga
- Department of Environmental Sciences, Jožef Stefan Institute, Ljubljana, Slovenia.
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11
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Gomes JR, Lobo A, Nogueira R, Terceiro AF, Costelha S, Lopes IM, Magalhães A, Summavielle T, Saraiva MJ. Neuronal megalin mediates synaptic plasticity-a novel mechanism underlying intellectual disabilities in megalin gene pathologies. Brain Commun 2020; 2:fcaa135. [PMID: 33225275 PMCID: PMC7667529 DOI: 10.1093/braincomms/fcaa135] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 07/14/2020] [Accepted: 07/16/2020] [Indexed: 12/15/2022] Open
Abstract
Donnai-Barrow syndrome, a genetic disorder associated to LRP2 (low-density lipoprotein receptor 2/megalin) mutations, is characterized by unexplained neurological symptoms and intellectual deficits. Megalin is a multifunctional endocytic clearance cell-surface receptor, mostly described in epithelial cells. This receptor is also expressed in the CNS, mainly in neurons, being involved in neurite outgrowth and neuroprotective mechanisms. Yet, the mechanisms involved in the regulation of megalin in the CNS are poorly understood. Using transthyretin knockout mice, a megalin ligand, we found that transthyretin positively regulates neuronal megalin levels in different CNS areas, particularly in the hippocampus. Transthyretin is even able to rescue megalin downregulation in transthyretin knockout hippocampal neuronal cultures, in a positive feedback mechanism via megalin. Importantly, transthyretin activates a regulated intracellular proteolysis mechanism of neuronal megalin, producing an intracellular domain, which is translocated to the nucleus, unveiling megalin C-terminal as a potential transcription factor, able to regulate gene expression. We unveil that neuronal megalin reduction affects physiological neuronal activity, leading to decreased neurite number, length and branching, and increasing neuronal susceptibility to a toxic insult. Finally, we unravel a new unexpected role of megalin in synaptic plasticity, by promoting the formation and maturation of dendritic spines, and contributing for the establishment of active synapses, both in in vitro and in vivo hippocampal neurons. Moreover, these structural and synaptic roles of megalin impact on learning and memory mechanisms, since megalin heterozygous mice show hippocampal-related memory and learning deficits in several behaviour tests. Altogether, we unveil a complete novel role of megalin in the physiological neuronal activity, mainly in synaptic plasticity with impact in learning and memory. Importantly, we contribute to disclose the molecular mechanisms underlying the cognitive and intellectual disabilities related to megalin gene pathologies.
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Affiliation(s)
- João R Gomes
- Molecular Neurobiology Unit, IBMC- Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal.,I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - Andrea Lobo
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.,Addiction Biology Group, IBMC- Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal
| | - Renata Nogueira
- Molecular Neurobiology Unit, IBMC- Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal.,I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - Ana F Terceiro
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.,Addiction Biology Group, IBMC- Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal
| | - Susete Costelha
- Molecular Neurobiology Unit, IBMC- Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal.,I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - Igor M Lopes
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.,Addiction Biology Group, IBMC- Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal
| | - Ana Magalhães
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.,Addiction Biology Group, IBMC- Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal
| | - Teresa Summavielle
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.,Addiction Biology Group, IBMC- Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal
| | - Maria J Saraiva
- Molecular Neurobiology Unit, IBMC- Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal.,I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
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12
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Kikuyama T, Susa T, Tamamori-Adachi M, Iizuka M, Akimoto M, Okinaga H, Fujigaki Y, Uchida S, Shibata S, Okazaki T. 25(OH)D 3 stimulates the expression of vitamin D target genes in renal tubular cells when Cyp27b1 is abrogated. J Steroid Biochem Mol Biol 2020; 199:105593. [PMID: 31945466 DOI: 10.1016/j.jsbmb.2020.105593] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 01/10/2020] [Accepted: 01/13/2020] [Indexed: 12/28/2022]
Abstract
Recently, it was reported that 25(OH)D3 (25D3) has physiological bioactivity in certain tissues derived from Cyp27b1 knockout mice. To investigate the function of 25D3 in the kidney as an informational crossroad of various calciotropic substances, we employed the CRISPR-Cas9 system to knock out Cyp27b1 in the mouse renal distal tubular mDCT cell line. Unlike the previously reported mice in which Cyp27b1 was targeted systemically, Cyp27b1 knockout mDCT cells did not produce any measurable 1α,25(OH)2D3 (1,25D3) after 25D3 administration. As was seen with treatment of Cyp27b1 knockout mDCT cells with ≥10-8 M of 1,25D3, the administration of 10-7 M of 25D3 translocated the vitamin D3 receptor (VDR) into the nucleus and promoted the expression of the representative 1,25D3-responsive gene Cyp24a1. The exhaustive target gene profiles of 25D3 were similar to those of 1,25D3. Subsequently, we confirmed that 25D3 induced the expression of the calcium reabsorption-related gene calbindin-D9K, in a way similar to 1,25D3. We also found that 1,25D3 and 25D3 induced the expression of the megalin gene. A chromatin immunoprecipitation assay identified two vitamin D response elements in the upstream region of the megalin gene that seemed to contribute to its expression. Together, we surmise that the ability of 25D3 to stimulate VDR target genes may provide a novel perspective for its role in certain tissues.
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Affiliation(s)
- Takahiro Kikuyama
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Takao Susa
- Department of Biochemistry, Teikyo University School of Medicine, Tokyo, Japan.
| | | | - Masayoshi Iizuka
- Department of Biochemistry, Teikyo University School of Medicine, Tokyo, Japan
| | - Miho Akimoto
- Department of Biochemistry, Teikyo University School of Medicine, Tokyo, Japan
| | - Hiroko Okinaga
- Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Yoshihide Fujigaki
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Shunya Uchida
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Shigeru Shibata
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan.
| | - Tomoki Okazaki
- Department of Biochemistry, Teikyo University School of Medicine, Tokyo, Japan
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13
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Zakiyanov O, Kalousová M, Zima T, Tesař V. Matrix Metalloproteinases in Renal Diseases: A Critical Appraisal. Kidney Blood Press Res 2019; 44:298-330. [PMID: 31185475 DOI: 10.1159/000499876] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 03/10/2019] [Indexed: 11/19/2022] Open
Abstract
Matrix metalloproteinases (MMPs) are endopeptidases within the metzincin protein family that not only cleave extracellular matrix (ECM) components, but also process the non-ECM molecules, including various growth factors and their binding proteins. MMPs participate in cell to ECM interactions, and MMPs are known to be involved in cell proliferation mechanisms and most probably apoptosis. These proteinases are grouped into six classes: collagenases, gelatinases, stromelysins, matrilysins, membrane type MMPs, and other MMPs. Various mechanisms regulate the activity of MMPs, inhibition by tissue inhibitors of metalloproteinases being the most important. In the kidney, intrinsic glomerular cells and tubular epithelial cells synthesize several MMPs. The measurement of circulating MMPs can provide valuable information in patients with kidney diseases. They play an important role in many renal diseases, both acute and chronic. This review attempts to summarize the current knowledge of MMPs in the kidney and discusses recent data from patient and animal studies with reference to specific diseases. A better understanding of the MMPs' role in renal remodeling may open the way to new interventions favoring deleterious renal changes in a number of kidney diseases.
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Affiliation(s)
- Oskar Zakiyanov
- Department of Nephrology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czechia,
| | - Marta Kalousová
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czechia
| | - Tomáš Zima
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czechia
| | - Vladimír Tesař
- Department of Nephrology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czechia
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14
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Cabezas F, Farfán P, Marzolo MP. Participation of the SMAD2/3 signalling pathway in the down regulation of megalin/LRP2 by transforming growth factor beta (TGF-ß1). PLoS One 2019; 14:e0213127. [PMID: 31120873 PMCID: PMC6532859 DOI: 10.1371/journal.pone.0213127] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 05/08/2019] [Indexed: 12/19/2022] Open
Abstract
Megalin/LRP2 is a receptor that plays important roles in the physiology of several organs, such as kidney, lung, intestine, and gallbladder and also in the physiology of the nervous system. Megalin expression is reduced in diseases associated with fibrosis, including diabetic nephropathy, hepatic fibrosis and cholelithiasis, as well as in some breast and prostate cancers. One of the hallmarks of these conditions is the presence of the cytokine transforming growth factor beta (TGF-ß). Although TGF-ß has been implicated in the reduction of megalin levels, the molecular mechanism underlying this regulation is not well understood. Here, we show that treatment of two epithelial cell lines (from kidney and gallbladder) with TGF-ß1 is associated with decreased megalin mRNA and protein levels, and that these effects are reversed by inhibiting the TGF-ß1 type I receptor (TGF-ßRI). Based on in silico analyses, the two SMAD-binding elements (SBEs) in the megalin promoter are located at positions -57 and -605. Site-directed mutagenesis of the SBEs and chromatin immunoprecipitation (ChIP) experiments revealed that SMAD2/3 transcription factors interact with SBEs. Both the presence of SMAD2/3 and intact SBEs were associated with repression of the megalin promoter, in the absence as well in the presence of TGF-ß1. Also, reduced megalin expression and promoter activation triggered by high concentration of albumin are dependent on the expression of SMAD2/3. Interestingly, the histone deacetylase inhibitor Trichostatin A (TSA), which induces megalin expression, reduced the effects of TGF-ß1 on megalin mRNA levels. These data show the significance of TGF-ß and the SMAD2/3 signalling pathway in the regulation of megalin and explain the decreased megalin levels observed under conditions in which TGF-ß is upregulated, including fibrosis-associated diseases and cancer.
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Affiliation(s)
- Felipe Cabezas
- Laboratorio de Tráfico Intracelular y Señalización, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pamela Farfán
- Laboratorio de Tráfico Intracelular y Señalización, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - María-Paz Marzolo
- Laboratorio de Tráfico Intracelular y Señalización, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- * E-mail:
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15
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Significance of urinary C-megalin excretion in vitamin D metabolism in pre-dialysis CKD patients. Sci Rep 2019; 9:2207. [PMID: 30778159 PMCID: PMC6379559 DOI: 10.1038/s41598-019-38613-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 12/27/2018] [Indexed: 11/08/2022] Open
Abstract
Serum 1,25(OH)2D and 24,25(OH)2D are decreased in CKD. Megalin in proximal tubular epithelial cells reabsorbs glomerular-filtered 25(OH)D-DBP complex to convert 25(OH)D to 1,25(OH)2D and 24,25(OH)2D. Urinary C-megalin excretion is increased via exocytosis from injured nephrons overloaded with megalin-mediated protein metabolism. This study investigated the significance of urinary C-megalin excretion in vitamin D metabolism in 153 pre-dialysis CKD patients. Urinary C-megalin was positively associated with urinary protein, β2MG and α1MG, and exhibited negative correlations with serum 25(OH)D, 1,25(OH)2D and 24,25(OH)2D. Multiple regression analysis showed that urinary C-megalin had a significantly negative association with 25(OH)D. Serum 1,25(OH)2D and 24,25(OH)2D, as well as 1,25(OH)2D/25(OH)D and 24,25(OH)2D/25(OH)D ratios, showed positive correlations with eGFR. Additionally, wholePTH was positively associated with 1,25(OH)2D/25(OH)D and 1,25(OH)2D/24,25(OH)2D, while FGF23 was positively associated with 24,25(OH)2D/25(OH)D and negatively with 1,25(OH)2D/24,25(OH)2D. Urinary C-megalin emerged as an independent factor positively associated with 1,25(OH)2D/25(OH)D and 1,25(OH)2D/24,25(OH)2D. Although 1,25(OH)2D and 24,25(OH)2D are decreased in CKD patient serum, our findings suggest that PTH and FGF23 retain their effects to regulate vitamin D metabolism even in the kidneys of these patients, while production of 1,25(OH)2D and 24,25(OH)2D from 25(OH)D is restricted due to either impairment of megalin-mediated reabsorption of the 25(OH)D-DBP complex or reduced renal mass.
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16
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Chapron BD, Chapron A, Phillips B, Okoli MC, Shen DD, Kelly EJ, Himmelfarb J, Thummel KE. Reevaluating the role of megalin in renal vitamin D homeostasis using a human cell-derived microphysiological system. ALTEX-ALTERNATIVES TO ANIMAL EXPERIMENTATION 2018; 35:504-515. [PMID: 29999169 PMCID: PMC6896899 DOI: 10.14573/altex.1803161] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 06/29/2018] [Indexed: 01/08/2023]
Abstract
The role of megalin in the regulation of renal vitamin D homeostasis has previously been evaluated in megalin-knockout mice and rat proximal tubule epithelial cells. We revisited these hypotheses that were previously tested solely in rodent models, this time using a 3-dimensional proximal tubule microphysiological system incorporating primary human proximal tubule epithelial cells. Using this human cell-derived model, we confirmed that 25OHD3 is transported into the human proximal tubule epithelium via megalin-mediated endocytosis while bound to vitamin D binding protein. Building upon these findings, we then evaluated the role of megalin in modulating the cellular uptake and biological activity of 1α,25(OH)2D3. Inhibition of megalin function decreased the 1α,25(OH)2D3-mediated induction of both cytochrome P450 24A1 protein levels and 24-hydroxylation activity following perfusion with vitamin D binding protein and 1α,25(OH)2D3. The potential for reciprocal effects from 1α,25(OH)2D3 on megalin expression were also tested. Contrary to previously published observations from rat proximal tubule epithelial cells, 1α,25(OH)2D3 did not induce megalin gene expression, thus highlighting the potential for meaningful interspecies differences in the homeostatic regulation of megalin in rodents and humans. These findings challenge a recently promoted hypothesis, predicated on the rodent cell data, that attempts to connect 1α,25(OH)2D3-mediated regulation of renal megalin expression and the pathology of chronic kidney disease in humans. In addition to providing specific insights related to the importance of renal megalin in vitamin D homeostasis, these results constitute a proof-of-concept that human-derived microphysiological systems are a suitable replacement for animal models for quantitative pharmacology and physiology research.
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Affiliation(s)
- Brian D Chapron
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Alenka Chapron
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Brian Phillips
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Miracle C Okoli
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Danny D Shen
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Edward J Kelly
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | | | - Kenneth E Thummel
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
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17
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Vitamin D Metabolism-Related Gene Haplotypes and Their Association with Metabolic Disturbances Among African-American Urban Adults. Sci Rep 2018; 8:8035. [PMID: 29795187 PMCID: PMC5966433 DOI: 10.1038/s41598-018-26230-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 04/13/2018] [Indexed: 01/23/2023] Open
Abstract
Epidemiological studies have confirmed associations of the vitamin D receptor (VDR) and vitamin D-related gene polymorphisms with adiposity and other metabolic disturbances. Those associations may be sex-specific. We evaluated the cross-sectional and longitudinal relationships between metabolic disturbances and haplotypes constructed from single nucleotide polymorphisms of VDR (BsmI:G/A: rs1544410; ApaI:A/C: rs7975232; and TaqI:G/A: rs731236) and MEGALIN (rs3755166:G/A; rs2075252:C/T and rs2228171:C/T) genes, in a sample of African-American adults. From 1,024 African Americans participating in the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS, 2004–2013, Baltimore, MD), our analyses included 539 participants with complete genetic, baseline covariate and metabolic outcome data (at baseline and follow-up). Mean ± SD period of follow-up was 4.64 ± 0.93 y. Multivariable-adjusted Cox proportional hazards and logistic regression models were conducted. Among key findings, in men, incident hypertension was inversely related to MEGALIN1 (GCC), [HR = 0.45, 95% CI: 0.23–0.90, p = 0.024]. Overall, there was a direct, linear dose-response association between VDR2 (AAG: BAt) and MetS at baseline [OR = 1.60, 95% CI: 1.11–2.31, p = 0.012], while among men, VDR3 (GAA: bAT) was inversely related to baseline MetS [OR = 0.40, 95% CI: 0.19–0.81, p = 0.011]. In conclusion, VDR and MEGALIN gene variations can affect prevalent MetS and the incidence rate of hypertension, respectively, among African-American urban adults.
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18
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Aragonès G, Ardid-Ruiz A, Ibars M, Suárez M, Bladé C. Modulation of leptin resistance by food compounds. Mol Nutr Food Res 2016; 60:1789-803. [DOI: 10.1002/mnfr.201500964] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/22/2016] [Accepted: 01/25/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Gerard Aragonès
- Department of Biochemistry and Biotechnology; Nutrigenomics Research Group; Universitat Rovira i Virgili; Tarragona Spain
| | - Andrea Ardid-Ruiz
- Department of Biochemistry and Biotechnology; Nutrigenomics Research Group; Universitat Rovira i Virgili; Tarragona Spain
| | - Maria Ibars
- Department of Biochemistry and Biotechnology; Nutrigenomics Research Group; Universitat Rovira i Virgili; Tarragona Spain
| | - Manuel Suárez
- Department of Biochemistry and Biotechnology; Nutrigenomics Research Group; Universitat Rovira i Virgili; Tarragona Spain
| | - Cinta Bladé
- Department of Biochemistry and Biotechnology; Nutrigenomics Research Group; Universitat Rovira i Virgili; Tarragona Spain
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19
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Ko EJ, Kim BH, Jeong HY, Soe SU, Yang DH, Lee SY. Serum 25-hydroxyvitamin D as a predictor of hospitalization-free survival in predialysis and dialysis patients with chronic kidney disease: a single-center prospective observational analysis. Kidney Res Clin Pract 2016; 35:22-8. [PMID: 27069854 PMCID: PMC4811977 DOI: 10.1016/j.krcp.2015.12.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 12/11/2015] [Accepted: 12/18/2015] [Indexed: 12/16/2022] Open
Abstract
Background Vitamin D has pleiotropic effects important for the proper functioning of multiple organ systems. We investigated whether serum 25-hydroxyvitamin D [25(OH)D] levels influenced hospitalization-free survival in patients with chronic kidney disease (CKD). Methods In this prospective study, serum levels of 25(OH)D were measured in 210 patients with CKD in the winter of 2009. Data regarding hospitalizations were collected over the subsequent 3 years. Results Vitamin D deficiency, as defined by a serum 25(OH)D level below 15 ng/mL, was observed in 76.7% of the patients. The mean 25(OH)D serum level was 13.6 ± 7.8 ng/mL in predialysis patients (n = 62) and 11.3 ± 6.7 ng/mL in dialysis patients (n = 148). During the follow-up, 107 patients (28 predialysis and 79 dialysis) were hospitalized because of infectious (33.6%) or cardiovascular diseases (23.4%). Predialysis and dialysis groups were divided into 2 subgroups based on the median 25(OH)D serum level. Kaplan–Meier analysis revealed that the risk of hospitalization was significantly lower in both predialysis and dialysis patients with above-median serum 25(OH)D levels (log-rank test; P = 0.043 and 0.002, respectively). Multivariate Cox proportional hazards models also demonstrated that the risk of hospitalization was significantly lower for patients with higher serum 25(OH)D levels in both the predialysis (hazard ratio, 0.963; 95% confidence interval, 0.93–0.99) and dialysis groups (hazard ratio, 0.955; 95% confidence interval, 0.91–0.99). Conclusion A lower serum 25(OH)D level predicted poorer hospitalization-free survival in both predialysis and dialysis CKD patients.
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Affiliation(s)
- Eun-Jung Ko
- Department of Internal Medicine, CHA Bundang Medical Center, CHA University, Seongnam, Korea
| | - Bo Hye Kim
- Department of Internal Medicine, CHA Bundang Medical Center, CHA University, Seongnam, Korea
| | - Hye Yun Jeong
- Department of Internal Medicine, CHA Bundang Medical Center, CHA University, Seongnam, Korea
| | - Sung Un Soe
- Department of Internal Medicine, CHA Bundang Medical Center, CHA University, Seongnam, Korea
| | - Dong Ho Yang
- Department of Internal Medicine, CHA Bundang Medical Center, CHA University, Seongnam, Korea
| | - So-Young Lee
- Department of Internal Medicine, CHA Bundang Medical Center, CHA University, Seongnam, Korea
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20
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Lu X, Elizondo RA, Nielsen R, Christensen EI, Yang J, Hammock BD, Watsky MA. Vitamin D in Tear Fluid. Invest Ophthalmol Vis Sci 2015; 56:5880-7. [PMID: 26348637 DOI: 10.1167/iovs.15-17177] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine the source(s) of vitamin D in tear fluid and examine the expression of the endocytic proteins and putative vitamin D transporters megalin and cubilin in lacrimal and Harderian glands. METHODS Wild-type, heterozygous, and vitamin D receptor (VDR) knockout C57BL/6 mice were used, with a subset of knockout mice fed a replenishment diet for some studies. Mouse lacrimal and Harderian glands from each group were used to measure megalin and cubilin by RT-PCR, Western blot, and immunohistochemistry. New Zealand white rabbits were used to collect lacrimal and accessory gland fluid for vitamin D mass spectroscopy measurements. RESULTS Ten-week-old knockout mice were significantly (P < 0.05) smaller than wild-type mice. Real-time PCR and Western blot showed decreased expression of megalin and cubilin in select VDR knockout mouse groups. Immunohistochemistry showed apical duct cell megalin staining and weaker megalin staining in VDR knockout mice compared with controls. Vitamin D2 was more prevalent in rabbit lacrimal and accessory gland fluid than vitamin D3, and greater amounts of Vitamin D2 were found in in tear fluid obtained directly from lacrimal and accessory glands as compared with plasma concentrations. CONCLUSIONS This is the first study to demonstrate the presence of megalin and cubilin in lacrimal and accessory glands responsible for producing tear fluid. The results strengthen the hypothesis that megalin and cubilin are likely involved in the secretory pathway of vitamin D into tear fluid by the duct cells.
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Affiliation(s)
- Xiaowen Lu
- Department of Cell Biology and Anatomy Georgia Regents University, Augusta, Georgia, United States
| | - Rodolfo A Elizondo
- Department of Cell Biology and Anatomy Georgia Regents University, Augusta, Georgia, United States
| | - Rikke Nielsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Jun Yang
- Department of Entomology and Nematology & UCD Comprehensive Cancer Center, University of California-Davis, Davis, California, United States
| | - Bruce D Hammock
- Department of Entomology and Nematology & UCD Comprehensive Cancer Center, University of California-Davis, Davis, California, United States
| | - Mitchell A Watsky
- Department of Cell Biology and Anatomy Georgia Regents University, Augusta, Georgia, United States
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21
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Lee YJ, Oh IH, Baek HJ, Lee CH, Lee SS. Effects of sun exposure and dietary vitamin D intake on serum 25-hydroxyvitamin D status in hemodialysis patients. Nutr Res Pract 2015; 9:158-64. [PMID: 25861422 PMCID: PMC4388947 DOI: 10.4162/nrp.2015.9.2.158] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 12/03/2014] [Accepted: 12/14/2014] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND/OBJECTIVES Vitamin D deficiency is common in hemodialysis patients. The aim of this study was to identify whether or not sun exposure and dietary vitamin D intake have effects on serum 25-hydroxyvitamin D (25(OH)D) status in hemodialysis (HD) patients. The objective was to identify the main determinants of serum vitamin D status in the study subjects. SUBJECTS/METHODS A cross-sectional study of 47 HD patients (19 males and 28 females) was performed. We assessed serum 25(OH)D and 1,25(OH)2D levels between August and September 2012 and analyzed the prevalence of vitamin D deficiency in HD patients. To evaluate the determinants of serum 25(OH)D levels, we surveyed dietary vitamin D intake, degree of sun exposure, and outdoor activities. To compare biological variables, serum 25(OH)D was stratified as below 15 ng/ml or above 15 ng/ml. RESULTS Mean 25(OH)D and 1,25(OH)2D levels were 13.5 ± 5.8 ng/ml and 20.6 ± 11.8 pg/ml, respectively. The proportions of serum 25(OH)D deficiency (< 15 ng/ml), insufficiency (15-< 30 ng/ml), and sufficiency (≥ 30 ng/ml) in subjects were 72.4%, 23.4%, and 4.3%, respectively. Prevalence of vitamin D deficiency in female patients was 78.6%, whereas that in males was 63.2% (P = 0.046). Vitamin D intake and sun exposure time were not significantly different between the two stratified serum 25(OH)D levels. Dietary intake of vitamin D did not contribute to increased serum 25(OH)D levels in HD patients. The main effective factors affecting serum 25(OH)D status were found to be the sun exposure and active outdoor exercise. CONCLUSIONS Hypovitaminosis D is common in HD patients and is higher in females than in males. Sun exposure is the most important determinant of serum 25(OH)D status in HD patients.
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Affiliation(s)
- Yeon Joo Lee
- Department of Food and Nutrition, Hanyang University, 222, Wangsimni-ro, Seongdong-gu, Seoul 133-791, Korea
| | - Il Hwan Oh
- Department of Nephrology, Hanyang University Seoul Hospital, Seoul 133-792, Korea
| | - Hee Jun Baek
- Department of Nutrition, Hanyang University Seoul Hospital, Seoul 133-792, Korea
| | - Chang Hwa Lee
- Department of Nephrology, Hanyang University Seoul Hospital, Seoul 133-792, Korea
| | - Sang Sun Lee
- Department of Food and Nutrition, Hanyang University, 222, Wangsimni-ro, Seongdong-gu, Seoul 133-791, Korea
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Vázquez-Carretero MD, Palomo M, García-Miranda P, Sánchez-Aguayo I, Peral MJ, Calonge ML, Ilundain AA. Dab2, megalin, cubilin and amnionless receptor complex might mediate intestinal endocytosis in the suckling rat. J Cell Biochem 2014; 115:510-22. [PMID: 24122887 DOI: 10.1002/jcb.24685] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 09/26/2013] [Indexed: 01/12/2023]
Abstract
We previously proposed that Dab2 participates in the endocytosis of milk macromolecules in rat small intestine. Here we investigate the receptors that may mediate this endocytosis by studying the effects of age and diet on megalin, VLDLR, and ApoER2 expression, and that of age on the expression of cubilin and amnionless. Of megalin, VLDLR and ApoER2, only the megalin expression pattern resembles that of Dab2 previously reported. Thus the mRNA and protein levels of megalin and Dab2 are high in the intestine of the suckling rat, down-regulated by age and up-regulated by milk diet, mainly in the ileum. Neither age nor diet affect ApoER2 mRNA levels. The effect of age on VLDLR mRNA levels depends on the epithelial cell tested but they are down-regulated by milk diet. In the suckling rat, the intestinal expressions of both cubilin and amnionless are similar to that of megalin and megalin, cubilin, amnionless and Dab2 co-localize at the microvilli and in the apical endocytic apparatus. Co-localization of Dab2 with ApoER2 and VLDLR at the microvilli and in the apical endocytic apparatus is also observed. This is the first report showing intestinal co-localization of: megalin/cubilin/amnionless/Dab2, VLDLR/Dab2 and ApoER2/Dab2. We conclude that the megalin/cubilin/amnionless/Dab2 complex/es participate in intestinal processes, mainly during the lactation period and that Dab2 may act as an adaptor in intestinal processes mediated by ApoER2 and VLDLR.
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Arcidiacono MV, Yang J, Fernandez E, Dusso A. The induction of C/EBPβ contributes to vitamin D inhibition of ADAM17 expression and parathyroid hyperplasia in kidney disease. Nephrol Dial Transplant 2014; 30:423-33. [PMID: 25294851 DOI: 10.1093/ndt/gfu311] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND In secondary hyperparathyroidism (SHPT), enhanced parathyroid levels of transforming growth factor-α (TGFα) increase EGF receptor (EGFR) activation causing parathyroid hyperplasia, high parathyroid hormone (PTH) and also reductions in vitamin D receptor (VDR) that limit vitamin D suppression of SHPT. Since anti-EGFR therapy is not an option in human SHPT, we evaluated ADAM17 as a therapeutic target to suppress parathyroid hyperplasia because ADAM17 is required to release mature TGFα, the most potent EGFR-activating ligand. METHODS Computer analysis of the ADAM17 promoter identified TGFα and C/EBPβ as potential regulators of the ADAM17 gene. Their regulation of ADAM17 expression, TGFα/EGFR-driven growth and parathyroid gland (PTG) enlargement were assessed in promoter-reporter assays in A431 cells and corroborated in rat and human SHPT, using erlotinib as anti-EGFR therapy to suppress TGFα signals, active vitamin D to induce C/EBPβ or the combination. RESULTS While TGFα induced ADAM17-promoter activity by 2.2-fold exacerbating TGFα/EGFR-driven growth, ectopic C/EBPβ expression completely prevented this vicious synergy. Accordingly, in advanced human SHPT, parathyroid ADAM17 levels correlated directly with TGFα and inversely with C/EBPβ. Furthermore, combined erlotinib + calcitriol treatment suppressed TGFα/EGFR-cell growth and PTG enlargement more potently than erlotinib in part through calcitriol induction of C/EBPβ to inhibit ADAM17-promoter activity, mRNA and protein. Importantly, in rat SHPT, the correction of vitamin D deficiency effectively reversed the resistance to paricalcitol induction of C/EBPβ to suppress ADAM17 expression and PTG enlargement, reducing PTH by 50%. CONCLUSION In SHPT, correction of vitamin D and calcitriol deficiency induces parathyroid C/EBPβ to efficaciously attenuate the severe ADAM17/TGFα synergy, which drives PTG enlargement and high PTH.
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Affiliation(s)
- Maria Vittoria Arcidiacono
- Renal Division, Washington University School of Medicine, St. Louis, MO, USA Division of Experimental Nephrology, IRB Lleida, Lleida, Spain
| | - Jing Yang
- Renal Division, Washington University School of Medicine, St. Louis, MO, USA
| | - Elvira Fernandez
- Division of Experimental Nephrology, IRB Lleida, Lleida, Spain Renal Division, Hospital Universitari Arnau de Vilanova, Universidad de Lleida, Lleida, Spain
| | - Adriana Dusso
- Renal Division, Washington University School of Medicine, St. Louis, MO, USA Division of Experimental Nephrology, IRB Lleida, Lleida, Spain
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Abstract
Chronic kidney disease (CKD) has been recognized as a significant global health problem because of the increased risk of total and cardiovascular morbidity and mortality. Vitamin D deficiency or insufficiency is common in patients with CKD, and serum levels of vitamin D appear to have an inverse correlation with kidney function. Growing evidence has indicated that vitamin D deficiency may contribute to deteriorating renal function, as well as increased morbidity and mortality in patients with CKD. Recent studies have suggested that treatment with active vitamin D or its analogues can ameliorate renal injury by reducing fibrosis, apoptosis, and inflammation in animal models; this treatment also decreases proteinuria and mortality in patients with CKD. These renoprotective effects of vitamin D treatment are far beyond its classical role in the maintenance of bone and mineral metabolism, in addition to its pleiotropic effects on extra-mineral metabolism. In this review, we discuss the altered metabolism of vitamin D in kidney disease, and the potential renoprotective mechanisms of vitamin D in experimental and clinical studies. In addition, issues regarding the effects of vitamin D treatment on clinical outcomes are discussed.
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Affiliation(s)
- Chang Seong Kim
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea
| | - Soo Wan Kim
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea
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25
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Vitamin D receptor and megalin gene polymorphisms are associated with central adiposity status and changes among US adults. J Nutr Sci 2013; 2:e33. [PMID: 25191583 PMCID: PMC4153078 DOI: 10.1017/jns.2013.19] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 04/01/2013] [Accepted: 05/03/2013] [Indexed: 01/13/2023] Open
Abstract
We examined longitudinal associations of vitamin D receptor (VDR) and megalin (LRP2; LDL receptor-related protein-2) gene polymorphisms with central adiposity. We used data from the Baltimore Longitudinal Study of Aging (BLSA), an ongoing prospective open cohort study. Study participants consisted of non-Hispanic white adults residing in Baltimore city, with one or more visits at age ≥50 years, and complete data (n 609-617). Repeated assessments on waist circumference (WC) and waist:hip ratio (WHR) were available. Multiple linear mixed models were used to estimate mid-follow-up age central adiposity level and annual rate of change with cut-points set at the sex-specific 80th percentile. The four binary outcomes were: 'elevated central adiposity' (ECA-WC and ECA-WHR) and 'significant increase in central adiposity' (SICA-WC and SICA-WHR). SNP for VDR (four SNP: (1) rs11568820 (CdX-2:T/C); (2) rs1544410 (BsmI:G/A); (3) rs7975232 (ApaI:A/C); (4) rs731236 (TaqI:G/A)) and Megalin (three SNP: (1) rs3755166:G/A; (2) rs2075252:C/T; (3) rs4668123:C/T) genes were selected. SNP latent classes (SNPLC) and SNP haplotypes (SNPHAP) were created. Multiple logistic regression analyses indicated that, in men, higher ECA-WHR odds were associated with SNPLC Megalin2:rs3755166[-]/rs2075252[TT]/rs4668123[T-] (v. Megalin1:rs3755166[-]/rs2075252[CC]/rs4668123[-]) (OR 2·87; 95 % CI 1·15, 7·12; P = 0·023) and that SNPLC Megalin3:rs3755166[-]/rs2075252[CT]/rs4668123[-] (v. Megalin1) was linked to lower SICA-WC odds (OR 0·48; 95 % CI 0·26, 0·88; P = 0·019) (P > 0·05 for sex × SNPLC). In women, VDR3 SNPHAP (GAA:bAT) was related to lower odds of ECA-WC (OR 0·37; 95 % CI 0·16, 0·87; P = 0·023) (P < 0·05 for sex × SNPHAP), VDR1 SNPHAP (GCA:baT) was associated with greater odds and VDR3 SNPHAP (GAA:bAT) with lower odds of SICA-WC (P > 0·05 for sex × SNPHAP). Vitamin D-related gene polymorphisms were associated with central adiposity status and change. Future mechanistic studies are needed to confirm those polymorphisms' biological significance to central adiposity.
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Key Words
- Adults
- BLSA, Baltimore Longitudinal Study of Aging
- Central adiposity
- ECA, elevated central adiposity
- LCA, latent class analysis
- LD, linkage disequilibrium
- Megalin
- SICA, significant increase in central adiposity
- SNP
- SNPHAP, SNP halotype
- SNPLC, SNP latent class
- VDR, vitamin D receptor
- Vitamin D receptor
- WC, waist circumference
- WHR, waist:hip ratio
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Oh SJ, Kim TH, Lim JM, Jeong JW. Progesterone induces expression of Lrp2 in the murine uterus. Biochem Biophys Res Commun 2013; 441:175-9. [PMID: 24140060 DOI: 10.1016/j.bbrc.2013.10.037] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 10/08/2013] [Indexed: 10/26/2022]
Abstract
Progesterone (P4) and progesterone receptor (PR) have important functions in uterine environment. In previous studies, using high density DNA microarray analysis, we identified low density lipoprotein receptor-related protein 2 (Lrp2) is one of the genes upregulated by P4 and PR. In present studies, we examined the expression of Lrp2 through real-time PCR, in situ hybridization and immunohistochemistry by P4-PR response. Lrp2 mRNA transcript was significantly increased after P4 treatment in the luminal and glandular epithelium of the wild-type mice. However, Lrp2 expression was not observed in the progesterone receptor knock out (PRKO) mice treated with P4. The expression of Lrp2 expression is not regulated by estrogen. During early pregnancy, the expression of Lrp2 was detected at 2.5 dpc and then significantly increased at 3.5 dpc in luminal and glandular epithelium. These results suggest that Lrp2 is a novel target gene by P4 and PR.
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Affiliation(s)
- Seo Jin Oh
- Department of Obstetrics and Gynecology & Reproductive Biology, Michigan State University, College of Human Medicine, Grand Rapids, MI 49503, United States; Major in Biomodulation, Seoul National University, Seoul, Republic of Korea
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27
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Haffner D, Querfeld U. Knochenstoffwechsel bei chronischer Niereninsuffizienz im Kindesalter. Monatsschr Kinderheilkd 2013. [DOI: 10.1007/s00112-013-2949-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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28
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Akour AA, Kennedy MJ, Gerk P. Receptor-Mediated Endocytosis across Human Placenta: Emphasis on Megalin. Mol Pharm 2013; 10:1269-78. [DOI: 10.1021/mp300609c] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Amal A. Akour
- Departments
of Pharmacotherapy and Outcomes Science and Pharmaceutics, School
of Pharmacy, Virginia Commonwealth University, Richmond, Virginia
| | - Mary Jayne Kennedy
- Departments
of Pharmacotherapy and Outcomes Science and Pharmaceutics, School
of Pharmacy, Virginia Commonwealth University, Richmond, Virginia
| | - Phillip Gerk
- Departments
of Pharmacotherapy and Outcomes Science and Pharmaceutics, School
of Pharmacy, Virginia Commonwealth University, Richmond, Virginia
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Day RT, Cavaglieri RC, Feliers D. Apelin retards the progression of diabetic nephropathy. Am J Physiol Renal Physiol 2013; 304:F788-800. [PMID: 23303408 PMCID: PMC3602700 DOI: 10.1152/ajprenal.00306.2012] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 01/04/2013] [Indexed: 12/14/2022] Open
Abstract
Apelin and its receptor APJ have pleiotropic effects in mice and humans and play a protective role in cardiovascular diseases at least partially by inhibiting oxidative stress. Our objective was to study the effect of apelin on the progression of kidney disease in mice with established type 1 diabetes. Ove26 mice with type 1 diabetes received daily subcutaneous injections of apelin for 2 or 14 wk. APJ localizes in the glomeruli and blood vessels of kidneys. Renal APJ expression was reduced in diabetic mice but increased after treatment with apelin. Apelin treatment did not affect glycemia, body weight, or blood pressure in diabetic mice. Whole kidney and glomerular hypertrophy, as well as renal inflammation, including monocyte chemoattractant protein 1 and vascular cell adhesion molecule 1 expression, NF-κB activation, and monocyte infiltration, was inhibited after short and long treatment with apelin. Apelin administration significantly reduced albuminuria at 6 mo. Short treatment with apelin was sufficient to reverse the downregulation of the antioxidant enzyme catalase. Expression of angiotensin II and angiotensin type 1 receptor (AT1) in kidneys from diabetic mice treated was not affected by apelin. These findings show for the first time that apelin exerts a protective effect on the diabetic kidney. Short administration is sufficient to reduce kidney and glomerular hypertrophy as well as renal inflammation, but prolonged treatment is required to improve albuminuria. This effect was independent of the activation of the renin angiotensin system but correlated with upregulation of the antioxidant catalase. Apelin may represent a novel tool to treat diabetic nephropathy.
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Affiliation(s)
- Robert T Day
- Department of Medicine/Renal Diseases, University of Texas Health Science Center, San Antonio, TX 78229, USA
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30
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Alvarez J, Wasse H, Tangpricha V. Vitamin D supplementation in pre-dialysis chronic kidney disease: A systematic review. DERMATO-ENDOCRINOLOGY 2012; 4:118-27. [PMID: 22928067 PMCID: PMC3427190 DOI: 10.4161/derm.20014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Vitamin D deficiency is associated with a variety of skeletal, cardiometabolic, and immunologic co-morbidities that are present in chronic kidney disease (CKD). We performed a systematic review to investigate the effects of vitamin D supplementation, in the form of ergocalciferol or cholecalciferol, on various health outcomes in early CKD. Seventeen clinical trials were identified, only two of which were randomized, placebo controlled trials. The majority of studies supplementing with > 2,000 IU/day of cholecalciferol achieved optimal vitamin D status, whereas studies supplementing with ergocalciferol were less consistent. Studies varied widely in their effects on lowering serum parathyroid hormone concentrations. Few studies investigated effects of vitamin D treatment on other clinical health indicators in early CKD. Rigorous studies are necessary to investigate optimal vitamin D dosing strategies in early CKD for the maintenance of adequate vitamin D status, management of secondary hyperparathyroidism and improvement of non-skeletal related clinical outcomes.
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31
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Antico A, Tozzoli R, Giavarina D, Tonutti E, Bizzaro N. Hypovitaminosis D as predisposing factor for atrophic type A gastritis: a case-control study and review of the literature on the interaction of Vitamin D with the immune system. Clin Rev Allergy Immunol 2012; 42:355-64. [PMID: 21286859 DOI: 10.1007/s12016-011-8255-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
1,25-Dihydroxyvitamin D displays immunoregulatory and anti-inflammatory properties, and the cells involved in innate and adaptive immune response express the vitamin D receptor and can both produce and respond to this hormone. This article aims at describing the complex immune regulatory role of vitamin D and depicting whether a correlation exists between atrophic type A gastritis and hypovitaminosis. We studied 62 autoimmune gastritis (AIG) patients and compared them to 54 lymphocytic gastritis patients, 21 Helicobacter pylori gastritis patients and 212 healthy subjects. We also statistically analyzed vitamin D concentration in 36,384 outpatients referred to our clinical laboratories. 25-Hydroxyvitamin D levels, the measurable metabolite used to determine vitamin D status in plasma, were measured by a chemiluminescent method. Average level of 25-OHD in AIG subjects was 9.8 ± 5.6 ng/mL (95% confidence interval (CI) 8.4-11.2), 11.1 ± 8.4 (CI 7.5-14.7) in H. pylori gastritis patients, 22.2 ± 13.5 (CI 18.6-25.8) in nonspecific lymphocytic gastritis patients, 21.3 ± 12.2 (CI 19.7-22.9) in healthy subjects, and 21.8 ± 13.1 (CI 21.7-21.9) in the 36,384 outpatients. Vitamin D levels in AIG patients were significantly lower than in patients with nonspecific gastritis or in the general population, supporting the hypothesis that hypovitaminosis D might be a risk factor for the development of autoimmune diseases. The low vitamin D concentration in H. pylori gastritis patients might act as predisposing factor for a more severe Th1-type aggression to the stomach epithelium.
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Affiliation(s)
- Antonio Antico
- Department of Clinical Pathology, Cittadella General Hospital, Cittadella, Italy
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Plieschnig JA, Gensberger ET, Bajari TM, Schneider WJ, Hermann M. Renal LRP2 expression in man and chicken is estrogen-responsive. Gene 2012; 508:49-59. [PMID: 22868208 PMCID: PMC3443750 DOI: 10.1016/j.gene.2012.07.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 06/25/2012] [Accepted: 07/15/2012] [Indexed: 01/03/2023]
Abstract
In mammals, low-density lipoprotein receptor-related protein-2 (LRP2) is an endocytic receptor that binds multiple ligands and is essential for a wide range of physiological processes. To gain new insights into the biology of this complex protein, we have initiated the molecular characterization of the LRP2 homolog from an oviparous species, the chicken (Gallus gallus). The galline LRP2 cDNA encodes a membrane protein of 4658 residues. Overall, the galline and human proteins are 73% identical, indicating that the avian gene has been well conserved over 300 million years. Unexpectedly, LRP2 transcript and protein levels in the kidney of females and estrogen-treated roosters were significantly higher than those in untreated males. The estrogen-responsiveness of avian LRP2 may be related to the dramatic differences in lipoprotein metabolism between mature roosters and laying hens. Newly identified potential estrogen-responsive elements (ERE) in the human and galline LRP2 gene, and additional Sp1 sites present in the promoter of the chicken gene, are compatible with both direct estrogen induction via the classical ligand-induced ERE pathway and the indirect transcription factor crosstalk pathway engaging the Sp1 sites. In agreement with this assumption, estrogen induction of LRP2 was observed not only in primary cultured chicken kidney cells, but also human kidney cell lines. These findings point to novel regulatory features of the LRP2 gene resulting in sex-specific receptor expression.
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Affiliation(s)
- Julia A Plieschnig
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Dr. Bohr-Gasse 9/2, A-1030 Vienna, Austria
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Beydoun MA, Ding EL, Beydoun HA, Tanaka T, Ferrucci L, Zonderman AB. Vitamin D receptor and megalin gene polymorphisms and their associations with longitudinal cognitive change in US adults. Am J Clin Nutr 2012; 95:163-78. [PMID: 22170372 PMCID: PMC3238459 DOI: 10.3945/ajcn.111.017137] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Vitamin D receptor (VDR) and the megalin gene polymorphism's link with longitudinal cognitive change remains unclear. OBJECTIVE The associations of single nucleotide polymorphisms (SNPs) for VDR [rs11568820 (CdX-2:T/C), rs1544410 (BsmI:G/A), rs7975232 (ApaI:A/C), rs731236 (TaqI:G/A)], and Megalin (rs3755166:G/A; rs2075252:C/T; rs4668123:C/T) genes with longitudinal cognitive performance changes were examined. DESIGN Data from 702 non-Hispanic white participants in the Baltimore Longitudinal Study of Aging were used. Longitudinal annual rates of cognitive change (LARCCs) between age 50 y and the individual mean follow-up age were predicted with linear mixed models by using all cognitive score time points (prediction I) or time points before dementia onset (prediction II). Latent class, haplotype, and ordinary least squares (OLS) regression analyses were conducted. RESULTS Among key findings, in OLS models with SNP latent classes as predictors for LARCCs, Megalin(2) [rs3755166(-)/rs2075252(TT)/rs4668123(T-)] compared with Megalin(1) [rs3755166(-)/rs2075252(CC)/rs4668123(-)] was associated with greater decline among men for verbal memory (prediction II). Significant sex differences were also found for SNP haplotype (SNPHAP). In women, VDR(1) [BsmI(G-)/ApaI(C-)/TaqI(A-); baT] was linked to a greater decline in category fluency (prediction I: β = -0.031, P = 0.012). The Megalin(1) SNPHAP (GCC) was related to greater decline among women for verbal memory, immediate recall [California Verbal Learning Test (CVLT), List A; prediction II: β = -0.043, P = 0.006) but to slower decline among men for delayed recall (CVLT-DR: β > 0, P < 0.0125; both predictions). In women, the Megalin(2) SNPHAP (ACC) was associated with slower decline in category fluency (prediction II: β = +0.026, P = 0.005). Another finding was that Megalin SNP rs3755166:G/A was associated with greater decline in global cognition in both sexes combined and in verbal memory in men. CONCLUSION Sex-specific VDR and Megalin gene variations can modify age-related cognitive decline among US adults.
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Affiliation(s)
- May A Beydoun
- National Institute on Aging, Intramural Research Program, NIH, Baltimore, MD, USA.
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Kidney disease and vitamin D levels: 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and VDR activation. Kidney Int Suppl (2011) 2011; 1:136-141. [PMID: 25018912 PMCID: PMC4089671 DOI: 10.1038/kisup.2011.30] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
A normal vitamin D status is essential for human health. Vitamin D deficiency is a recognized risk factor for all-cause mortality in normal individuals and in chronic kidney disease (CKD) patients. The link between vitamin D deficiency and death is a defective activation of the vitamin D receptor (VDR) by 1,25-dihydroxyvitamin D (calcitriol, the vitamin D hormone) to induce/repress genes that maintain mineral homeostasis and skeletal integrity, and prevent secondary hyperparathyroidism, hypertension, immune disorders, and renal and cardiovascular (CV) damage. The kidney is the main site for the conversion of 25-hydroxyvitamin D (25D) to circulating calcitriol, and therefore essential for the health benefits of endocrine VDR activation. The kidney is also essential for the uptake of 25D from the glomerular ultrafiltrate for its recycling to the circulation to maintain serum 25D levels, extrarenal calcitriol synthesis, and the prosurvival benefits of autocrine/paracrine VDR activation. Indeed, both calcitriol and vitamin D deficiency increase progressively in the course of CKD, and associate directly with accelerated disease progression and death. Therefore, the safe correction of calcitriol and vitamin D deficiency/insufficiency is becoming a high priority among nephrologists. This review updates the pathophysiology behind 25D and calcitriol deficiency and impaired VDR activation in CKD, the adequacy of current recommendations for vitamin D supplementation, and potential markers of the efficacy of therapy to prevent or slow the development of renal and CV lesions unrelated to parathyroid hormone suppression, a knowledge required for the design of trials to obtain evidence-based recommendations for vitamin D and calcitriol replacement at all stages of CKD.
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Abstract
In chronic kidney disease (CKD), abnormalities in vitamin D metabolism contribute to the development of mineral and skeletal disorders, elevations in parathyroid hormone (PTH), hypertension, systemic inflammation, renal and cardiovascular damage. CKD induces a progressive loss of the capacity of the kidney not only to convert 25-hydroxyvitamin D [25(OH)D] to circulating calcitriol, the vitamin D hormone, but also to maintain serum 25(OH)D levels for non-renal calcitriol synthesis. The resulting calcitriol and 25(OH)D deficiency associates directly with accelerated disease progression and death. This chapter presents our understanding of the pathophysiology behind 25(OH)D and calcitriol deficiency in CKD, of the adequacy of current recommendations for vitamin D supplementation and PTH suppression, and of potential markers of renal and cardiovascular lesions unrelated to PTH suppression, a knowledge required for the design of trials to obtain evidence-based recommendations for vitamin D and calcitriol replacement that improve outcomes at all stages of CKD.
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Affiliation(s)
- Adriana Dusso
- Division of Experimental Nephrology, IRBLleida (Lleida Institute for Biomedical Research), Avda Rovira Roure 80, Lleida, Spain.
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Abstract
The active metabolite of vitamin D apart from a crucial role in maintaining mineral homeostasis and skeletal functions, has antiproliferative, apoptosis and differentiation inducing as well as immunomodulatory effects in cancer. It is well known that with increasing sunshine exposure the incidence of breast, prostate and colorectal cancer is decreasing. A number of in vitro and in vivo experiments documented the effects of vitamin D in the inhibition of the tumorigenesis. In studying the role of vitamin D in cancer, it is imperative to examine the potential pathways that control local tissue levels of vitamin D. The enzyme 24-hydroxylase converts the active vitamin D to inactive metabolite. Extra-renal production of this enzyme is observed and has been increasingly recognized as present in cancer cells. This enzyme is rate limiting for the amount of local vitamin D in cancer tissues and elevated expression is associated with an adverse prognosis. 24-hydroxylase may be a predictive marker of vitamin D efficacy in patients with cancer as an adjunctive therapy. There are many vitamin D analogs with no pronounced hypercalcemizing effects. Some analogs are in phase 1 and 2 clinical test, and they might have a role in the therapy of several types of cancer. At present our main task is to make an effort to decrease the vitamin D deficiency in Hungary. Speer G. The D-day. The role of vitamin D in the prevention and the additional therapy of cancers.
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Affiliation(s)
- Gábor Speer
- Semmelweis Egyetem I. sz. Belgyógyászati Klinika 1125 Budapest Szilágyi Erzsébet fasor 38.
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Megalin/LRP2 expression is induced by peroxisome proliferator-activated receptor -alpha and -gamma: implications for PPARs' roles in renal function. PLoS One 2011; 6:e16794. [PMID: 21311715 PMCID: PMC3032793 DOI: 10.1371/journal.pone.0016794] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Accepted: 01/12/2011] [Indexed: 12/13/2022] Open
Abstract
Background Megalin is a large endocytic receptor with relevant functions during development and adult life. It is expressed at the apical surface of several epithelial cell types, including proximal tubule cells (PTCs) in the kidney, where it internalizes apolipoproteins, vitamins and hormones with their corresponding carrier proteins and signaling molecules. Despite the important physiological roles of megalin little is known about the regulation of its expression. By analyzing the human megalin promoter, we found three response elements for the peroxisomal proliferator-activated receptor (PPAR). The objective of this study was to test whether megalin expression is regulated by the PPARs. Methodology/Principal Findings Treatment of epithelial cell lines with PPARα or PPARγ ligands increased megalin mRNA and protein expression. The stimulation of megalin mRNA expression was blocked by the addition of specific PPARα or PPARγ antagonists. Furthermore, PPAR bound to three PPAR response elements located in the megalin promoter, as shown by EMSA, and PPARα and its agonist activated a luciferase construct containing a portion of the megalin promoter and the first response element. Accordingly, the activation of PPARα and PPARγ enhanced megalin expression in mouse kidney. As previously observed, high concentrations of bovine serum albumin (BSA) decreased megalin in PTCs in vitro; however, PTCs pretreated with PPARα and PPARγ agonists avoided this BSA-mediated reduction of megalin expression. Finally, we found that megalin expression was significantly inhibited in the PTCs of rats that were injected with BSA to induce tubulointerstitial damage and proteinuria. Treatment of these rats with PPARγ agonists counteracted the reduction in megalin expression and the proteinuria induced by BSA. Conclusions PPARα/γ and their agonists positively control megalin expression. This regulation could have an important impact on several megalin-mediated physiological processes and on pathophysiologies such as chronic kidney disease associated with diabetes and hypertension, in which megalin expression is impaired.
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Defective renal maintenance of the vitamin D endocrine system impairs vitamin D renoprotection: a downward spiral in kidney disease. Kidney Int 2011; 79:715-29. [PMID: 21270766 DOI: 10.1038/ki.2010.543] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In kidney disease, the progressive loss of renal capacity to produce calcitriol, the vitamin D hormone, is a key contributor to elevations in parathyroid hormone (PTH) and mineral and skeletal disorders predisposing to renal and cardiovascular damage, ectopic calcifications, and high mortality rates. Thus, the safe correction of calcitriol deficiency to suppress PTH has been the treatment of choice for decades. However, recent epidemiological and experimental data suggest that calcitriol replacement may improve outcomes through renal and cardioprotective actions unrelated to PTH suppression. Furthermore, a striking incidence of vitamin D deficiency occurs in kidney disease and associates more strongly than calcitriol deficiency with a higher risk for kidney disease progression and death. Despite the translational relevance of these findings, no prospective trials are currently available in support of the efficacy of vitamin D supplementation and/or calcitriol replacement to safely halt/moderate renal disease progression. This review updates the pathophysiology behind the vicious cycle by which kidney injury impairs the maintenance of normal vitamin D and calcitriol levels, which in turn impedes vitamin D/calcitriol renoprotective actions, a requirement for the design of prospective trials to improve current recommendations for vitamin D interventions at all stages of kidney disease.
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Rojas-Rivera J, De La Piedra C, Ramos A, Ortiz A, Egido J. The expanding spectrum of biological actions of vitamin D. Nephrol Dial Transplant 2010; 25:2850-65. [PMID: 20525641 DOI: 10.1093/ndt/gfq313] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- Jorge Rojas-Rivera
- IIS-Fundación Jimenez Diaz, Division of Nephrology and Hypertension, Laboratory of Experimental Nephrology and Vascular Pathology, Madrid, Spain.
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41
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Chlon TM, Taffany DA, Welsh J, Rowling MJ. Retinoids modulate expression of the endocytic partners megalin, cubilin, and disabled-2 and uptake of vitamin D-binding protein in human mammary cells. J Nutr 2008; 138:1323-8. [PMID: 18567755 PMCID: PMC2443692 DOI: 10.1093/jn/138.7.1323] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The major circulating form of vitamin D, 25-hydroxycholecalciferol (25D3), circulates bound to vitamin D-binding protein (DBP). Prior to activation to 1,25-dihydroxycholecalciferol in the kidney, the 25D3-DBP complex is internalized via receptor-mediated endocytosis, which is absolutely dependent on the membrane receptors megalin and cubilin and the adaptor protein disabled-2 (Dab2). We recently reported that mammary epithelial cells (T-47D) expressing megalin, cubilin, and Dab2 rapidly internalize DBP via endocytosis, whereas cells that do not express all 3 proteins (MCF-7) do not. The objectives of this study were to characterize megalin, cubilin, and Dab2 expression and transport of DBP in human mammary epithelial cells. Using immunoblotting and real-time PCR, we found that megalin, cubilin, and Dab2 were expressed and dose dependently induced by all-trans-retinoic acid (RA) in T-47D human breast cancer cells and that RA-treated T-47D cells exhibited enhanced DBP internalization. These are the first studies to our knowledge to demonstrate that mammary epithelial cells express megalin, cubilin, and Dab2, which are enhanced during differentiation and may explain, at least in part, our finding that receptor-mediated endocytosis of DBP is upregulated in differentiated mammary epithelial cells.
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Affiliation(s)
- Timothy M. Chlon
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556
| | - David A. Taffany
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556
| | - JoEllen Welsh
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556
| | - Matthew J. Rowling
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011,* To whom correspondence should be addressed. E-mail;
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Abstract
A constant extracellular Ca2+ concentration is required for numerous physiological functions at tissue and cellular levels. This suggests that minor changes in Ca2+ will be corrected by appropriate homeostatic systems. The system regulating Ca2+ homeostasis involves several organs and hormones. The former are mainly the kidneys, skeleton, intestine and the parathyroid glands. The latter comprise, amongst others, the parathyroid hormone, vitamin D and calcitonin. Progress has recently been made in the identification and characterisation of Ca2+ transport proteins CaT1 and ECaC and this has provided new insights into the molecular mechanisms of Ca2+ transport in cells. The G-protein coupled calcium-sensing receptor, responsible for the exquisite ability of the parathyroid gland to respond to small changes in serum Ca2+ concentration was discovered about a decade ago. Research has focussed on the molecular mechanisms determining the serum levels of 1,25(OH)2D3, and on the transcriptional activity of the vitamin D receptor. The aim of recent work has been to elucidate the mechanisms and the intracellular signalling pathways by which parathyroid hormone, vitamin D and calcitonin affect Ca2+ homeostasis. This article summarises recent advances in the understanding and the molecular basis of physiological Ca2+ homeostasis.
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Affiliation(s)
- Indra Ramasamy
- Department of Chemical Pathology, Newham University Hospital, London, UK.
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43
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Moncayo R. Cubilin and megalin in radiation-induced renal injury with labelled somatostatin analogues: are we just dealing with the kidney? Eur J Nucl Med Mol Imaging 2006; 32:1131-5. [PMID: 16133381 DOI: 10.1007/s00259-005-1885-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Andress DL. Vitamin D in chronic kidney disease: A systemic role for selective vitamin D receptor activation. Kidney Int 2006; 69:33-43. [PMID: 16374421 DOI: 10.1038/sj.ki.5000045] [Citation(s) in RCA: 224] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Hyperparathyroidism occurs in most patients during the progression of chronic kidney disease (CKD) and one of its initiating events, reduced serum levels of 1,25-dihydroxyvitamin D, results from a decrease in renal 1alpha hydroxylase activity, which converts 25-hydroxyvitamin D to its activated form. The combination of persistently high parathyroid hormone (PTH) and low 1,25-dihydroxyvitamin D is associated with bone loss, cardiovascular disease, immune suppression and increased mortality in patients with end-stage kidney failure. Recent studies in dialysis patients suggest that paricalcitol, a selective activator of the vitamin D receptor (VDR), is associated with a more favorable efficacy to side effect profile than calcitriol, with less morbidity and better survival. One hypothesis derived from such studies suggests that systemic activation of VDRs may have direct effects on the cardiovascular system to decrease mortality in CKD. Although current guidelines for regulating serum calcium, phosphate and PTH recommend specific interventions at the various stages of CKD to prevent or postpone irreversible parathyroid disease and decrease cardiovascular morbidity and mortality, emerging data suggest that vitamin D therapy may prolong survival in this patient population by mechanisms that are independent of calcium, phosphate and PTH. It is suggested that a re-evaluation of current treatment recommendations is needed and that future research should focus on mechanisms that distinguish potential tissue specific benefits of selective VDR activators in patients with CKD.
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Affiliation(s)
- D L Andress
- Department of Medicine, VA Puget Sound Health Care System, Division of Nephrology, University of Washington, Seattle, Washington, USA.
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45
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Abstract
The vitamin D endocrine system plays an essential role in calcium homeostasis and bone metabolism, but research during the past two decades has revealed a diverse range of biological actions that include induction of cell differentiation, inhibition of cell growth, immunomodulation, and control of other hormonal systems. Vitamin D itself is a prohormone that is metabolically converted to the active metabolite, 1,25-dihydroxyvitamin D [1,25(OH)(2)D]. This vitamin D hormone activates its cellular receptor (vitamin D receptor or VDR), which alters the transcription rates of target genes responsible for the biological responses. This review focuses on several recent developments that extend our understanding of the complexities of vitamin D metabolism and actions: the final step in the activation of vitamin D, conversion of 25-hydroxyvitamin D to 1,25(OH)(2)D in renal proximal tubules, is now known to involve facilitated uptake and intracellular delivery of the precursor to 1alpha-hydroxylase. Emerging evidence using mice lacking the VDR and/or 1alpha-hydroxylase indicates both 1,25(OH)(2)D(3)-dependent and -independent actions of the VDR as well as VDR-dependent and -independent actions of 1,25(OH)(2)D(3). Thus the vitamin D system may involve more than a single receptor and ligand. The presence of 1alpha-hydroxylase in many target cells indicates autocrine/paracrine functions for 1,25(OH)(2)D(3) in the control of cell proliferation and differentiation. This local production of 1,25(OH)(2)D(3) is dependent on circulating precursor levels, providing a potential explanation for the association of vitamin D deficiency with various cancers and autoimmune diseases.
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Affiliation(s)
- Adriana S Dusso
- Renal Division, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
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46
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Erranz B, Miquel JF, Argraves WS, Barth JL, Pimentel F, Marzolo MP. Megalin and cubilin expression in gallbladder epithelium and regulation by bile acids. J Lipid Res 2004; 45:2185-98. [PMID: 15375181 DOI: 10.1194/jlr.m400235-jlr200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Cholesterol crystal formation in the gallbladder is a key step in gallstone pathogenesis. Gallbladder epithelial cells might prevent luminal gallstone formation through a poorly understood cholesterol absorption process. Genetic studies in mice have highlighted potential gallstone susceptibility alleles, Lith genes, which include the gene for megalin. Megalin, in conjunction with the large peripheral membrane protein cubilin, mediates the endocytosis of numerous ligands, including HDL/apolipoprotein A-I (apoA-I). Although the bile contains apoA-I and several cholesterol-binding megalin ligands, the expression of megalin and cubilin in the gallbladder has not been investigated. Here, we show that both proteins are expressed by human and mouse gallbladder epithelia. In vitro studies using a megalin-expressing cell line showed that lithocholic acid strongly inhibits and cholic and chenodeoxycholic acids increase megalin expression. The effects of bile acids (BAs) were also demonstrated in vivo, analyzing gallbladder levels of megalin and cubilin from mice fed with different BAs. The BA effects could be mediated by the farnesoid X receptor, expressed in the gallbladder. Megalin protein was also strongly increased after feeding a lithogenic diet. These results indicate a physiological role for megalin and cubilin in the gallbladder and provide support for a role for megalin in gallstone pathogenesis.
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Affiliation(s)
- Benjamín Erranz
- Center for Cell Regulation and Pathology "Joaquin V. Luco", Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, and Instituto Milenio de Biología Fundamental y Aplicada, Santiago, Chile
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Toribio RE, Kohn CW, Sams RA, Capen CC, Rosol TJ. Hysteresis and calcium set-point for the calcium parathyroid hormone relationship in healthy horses. Gen Comp Endocrinol 2003; 130:279-88. [PMID: 12606270 DOI: 10.1016/s0016-6480(02)00621-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Abnormalities in calcium (Ca(2+)) homeostasis are reported in horses with several pathological conditions; however, there is little information on Ca(2+) regulation in horses. The objectives of the present study were to determine the Ca(2+) set-point in healthy horses, to determine whether the Ca(2+)/parathyroid hormone (PTH) response curves were characterized by hysteresis, and to determine if the order of experimentally induced hypocalcemia or hypercalcemia had an effect on PTH secretion. The Ca(2+) set-point and hysteresis were determined in 12 healthy horses by infusing Na(2)EDTA and calcium gluconate. The Ca(2+) set-point was 1.37 +/- 0.05 mmol/L, which is higher than values reported for humans and dogs (1.0-1.2 mmol/L). Hysteresis was present during hypocalcemia and hypercalcemia. Horses in which hypocalcemia was followed by hypercalcemia secreted more PTH (7440 +/- 740 pmol min/L) than horses in which hypercalcemia was followed by hypocalcemia (5990 +/- 570 pmol min/L). This study has demonstrated that the Ca(2+) set-point in the horse is higher than in other domestic animals and man. We have shown that the Ca(2+)/PTH relationship in horses is sigmoidal and displays hysteresis during both hypocalcemia and hypercalcemia, and that extracellular Ca(2+) concentrations may affect the response of the parathyroid gland to hypocalcemia.
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Affiliation(s)
- Ramiro E Toribio
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA.
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48
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Christensen EI, Birn H. Megalin and cubilin: multifunctional endocytic receptors. Nat Rev Mol Cell Biol 2002; 3:256-66. [PMID: 11994745 DOI: 10.1038/nrm778] [Citation(s) in RCA: 578] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The ability to take up substances from the surrounding environment not only provides cells with vital nutrients, but also enables the selective transport of substances from one compartment to another. Megalin and cubilin are two structurally different endocytic receptors that interact to serve such functions. Evidence has accumulated in recent years to indicate that these receptors have important functions in both normal physiology and pathology.
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Affiliation(s)
- Erik Ilsø Christensen
- Department of Cell Biology, University of Aarhus, University Park, Building 234, DK-8000 Aarhus C, ;
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Moestrup SK, Verroust PJ. Megalin- and cubilin-mediated endocytosis of protein-bound vitamins, lipids, and hormones in polarized epithelia. Annu Rev Nutr 2001; 21:407-28. [PMID: 11375443 DOI: 10.1146/annurev.nutr.21.1.407] [Citation(s) in RCA: 141] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Polarized epithelia have several functional and morphological similarities, including a high capacity for uptake of various substances present in the fluids facing the apical epithelial surfaces. Studies during the past decade have shown that receptor-mediated endocytosis, rather than nonspecific pinocytosis, accounts for the apical epithelial uptake of many carrier-bound nutrients and hormones. The two interacting receptors of distinct evolutionary origin, megalin and cubilin, are main receptors in this process. Both receptors are apically expressed in polarized epithelia, in which they function as biological affinity matrices for overlapping repertoires of ligands. The ability to bind multiple ligands is accounted for by a high number of replicated low-density lipoprotein receptor type-A repeats in megalin and CUB (complement C1r/C1s, Uegf, and bone morphogenic protein-1) domains in cubilin. Here we summarize and discuss the structural, genetic, and functional aspects of megalin and cubilin, with emphasis on their function as receptors for uptake of protein-associated vitamins, lipids, and hormones.
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Affiliation(s)
- S K Moestrup
- Department of Medical Biochemistry, University of Aarhus, 8000 Arhus C, Denmark.
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Zhao J, Oleinikov AV, Oleinikova I, Makker SP. Functional characterization of rat gp600/megalin promoter: combination of proximal Sp1 site and JCV repeat is important in rat gp600/megalin promoter activation. Gene 2001; 265:123-31. [PMID: 11255015 DOI: 10.1016/s0378-1119(01)00351-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Gp600/megalin is an endocytic receptor belonging to the low-density lipoprotein receptor family. Up or down regulation of this protein were observed in certain disease states. To understand the mechanisms that control gp600/megalin gene expression, we cloned and functionally characterized a 738-bp fragment of the 5'-flanking region of rat gp600/megalin gene. A transcription start site was mapped to 33 bp downstream of TAGAAA sequence (TATA-like box). Multiple transcription factor binding sites were identified. Serial 5' deletions and transient transfection assays showed that the deletion fragment containing the Sp1 site proximal to the TATA-like box and a JCV repeat retained 80% of the promoter activity. Individual mutations of the proximal Sp1 site and JCV repeat reduced the promoter activity by 60 and 34% respectively. Double mutations of the proximal Sp1 site and JCV repeat produced a dramatic 80% reduction in the promoter activity. However, deletions and mutations or double mutations of other transcription factor binding sites in the promoter region had a minor effect on the promoter activity. These results indicate that the combination of proximal Sp1 site and the JCV repeat are necessary for activation of gp600/megalin expression. Moreover, Sp1 and Sp3 proteins interacted with the proximal and the distal Sp1 sites in the nuclear extracts of gp600/megalin expressing cell lines. TCF site seems to be involved in negative regulation of this promoter but no nuclear protein(s) were found to bind to this site. In addition, Ap2 site responsible for 28% promoter activity is able to bind two dominant unknown nuclear proteins. This functional characterization of the regulation of gp600/megalin gene is likely to advance the knowledge of the regulation of this gene in health and disease.
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Affiliation(s)
- J Zhao
- Department of Pediatrics, Division of Nephrology, School of Medicine, University of California, CA 95616, Davis, USA
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