1
|
Atcheson RJ, Burne THJ, Dawson PA. Serum sulfate level and Slc13a1 mRNA expression remain unaltered in a mouse model of moderate vitamin D deficiency. Mol Cell Biochem 2022:10.1007/s11010-022-04634-7. [PMID: 36566486 DOI: 10.1007/s11010-022-04634-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 12/05/2022] [Indexed: 12/26/2022]
Abstract
Sulfate is essential for healthy foetal growth and neurodevelopment. The SLC13A1 sulfate transporter is primarily expressed in the kidney where it mediates sulfate reabsorption and maintains circulating sulfate levels. To meet foetal demands, maternal sulfate levels increase by twofold in pregnancy via upregulated SLC13A1 expression. Previous studies found hyposulfataemia and reduced renal Slc13a1 mRNA expression in rodent models with either severe vitamin D deficiency or perturbed vitamin D signalling. Here we investigated a mouse model of moderate vitamin D deficiency. However, serum sulfate level and renal Slc13a1 mRNA expression was not decreased by a moderate reduction in circulating vitamin D level. We confirmed that the mouse Slc13a1 5'-flanking region was upregulated by 1,25(OH)2D3 using luciferase assays in a cultured renal OK cell line. These results support the presence of a functional VDRE in the mouse Slc13a1 but suggests that moderate vitamin D deficiency does not impact on sulfate homeostasis. As sulfate biology is highly conserved between rodents and humans, we proposed that human SLC13A1 would be under similar transcriptional regulation by 1,25(OH)2D3. Using an online prediction tool we identified a putative VDRE in the SLC13A1 5'-flanking region but unlike the mouse Slc13a1 sequence, the human sequence did not confer a significant response to 1,25(OH)2D3 in vitro. Overall, this study suggests that moderate vitamin D deficiency may not alter sulfate homeostasis. This needs to be confirmed in humans, particularly during pregnancy when vitamin D and sulfate levels need to be maintained at high levels for healthy maternal and child outcomes.
Collapse
Affiliation(s)
- Ranita J Atcheson
- Mater Research Institute, The University of Queensland, Translational Research Institute, 37 Kent St, Woolloongabba, QLD, 4102, Australia
| | - Thomas H J Burne
- Queensland Brain Institute, The University of Queensland, St. Lucia, QLD, 4072, Australia.,Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD, 4076, Australia
| | - Paul A Dawson
- Mater Research Institute, The University of Queensland, Translational Research Institute, 37 Kent St, Woolloongabba, QLD, 4102, Australia.
| |
Collapse
|
2
|
Zielinska N, Podgórski M, Haładaj R, Polguj M, Olewnik Ł. Risk Factors of Intervertebral Disc Pathology-A Point of View Formerly and Today-A Review. J Clin Med 2021; 10:409. [PMID: 33494410 DOI: 10.3390/jcm10030409] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/16/2021] [Accepted: 01/20/2021] [Indexed: 12/18/2022] Open
Abstract
Intervertebral disc pathology is a common disorder that can be caused by genetic, mechanical, and behavioral factors; however, it is possible to slow its progression. Although environmental and behavioral factors were previously considered to be the sole causes of intervertebral disc pathologies such as disc herniation, recent studies have shown that genetic factors also play an important role. This review compares the perception of major risk factors from the last and present centuries. It also examines individual genetic and non-genetic factors acting as risk factors, as well as some approaches for preventing intervertebral disc pathologies, and compares available statistics regarding disc herniation.
Collapse
|
3
|
Doraisamy R, Ramaswami K, Shanmugam J, Subramanian R, Sivashankaran B. Genetic risk factors for lumbar disc disease. Clin Anat 2020; 34:51-56. [PMID: 32583875 DOI: 10.1002/ca.23641] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 06/18/2020] [Indexed: 01/08/2023]
Abstract
AIM AND BACKGROUND Lumbar disc degeneration (LDD) is thought to be multifactorial in origin. Very recently the focus has shifted to the involvement of a family of candidate genes in the pathogenesis of LDD. There is particular emphasis on the vitamin D receptor gene (VDR gene). The VDR polymorphisms FOK1, TAQ1, and APO1 have been variably associated with LDD. OBJECTIVE To evaluate the association between the FOK1/Taq1 genes and LDD. MATERIALS AND METHODS One hundred unrelated healthy (asymptomatic) individuals who presented for routine health checkup and 93 consecutive patients (43 males and 50 females) with no history of low back pain were enrolled in the study after informed consent was obtained. The MRI images of cases and controls were graded and peripheral blood samples were collected from all participants and sent for genetic analysis. RESULTS Individuals with the dominant genotype for Taq1 had a significantly higher association with LDD than those without it. There was no association between LDD and the Fok1 genotype. CONCLUSION Genetic predisposition is an important risk factor for LDD.
Collapse
Affiliation(s)
- Ravichandran Doraisamy
- Department of Anatomy, KMCH Institute of Health Sciences and Research (KMCH IHSR), Coimbatore, India
| | - Karthikeyan Ramaswami
- Department of Orthopaedics, Karpagam Faculty of Medical Sciences and Research (KFMSR), Coimbatore, India
| | - Jeevithan Shanmugam
- Department of Community Medicine, KMCH Institute of Health Sciences and Research (KMCH IHSR), Coimbatore, India
| | - Rashmi Subramanian
- Central Research Laboratory, Karpagam Faculty of Medical Sciences and Research (KFMSR), Coimbatore, India
| | | |
Collapse
|
4
|
Lee S, Temple FT, Dawson PA. Kidney microRNA profile in pregnant mice reveals molecular insights into kidney adaptation to pregnancy: A pilot study. Mol Genet Metab Rep 2019; 20:100486. [PMID: 31249785 PMCID: PMC6587019 DOI: 10.1016/j.ymgmr.2019.100486] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 06/12/2019] [Indexed: 02/06/2023] Open
Abstract
The maternal kidneys undergo numerous physiological changes during pregnancy to maintain a healthy pregnancy for mother and child. Over the past decade, interest in microRNAs (miRNAs) for regulating gene expression during pregnancy has expanded. However, the role of miRNAs in modulating kidney physiology during pregnancy has not been extensively investigated. In this study, miRNome profiling suggested differential expression of 163 miRNAs (of 887 miRNAs detected) in the kidneys from pregnant mice at 6.5 days gestation when compared to non-pregnant female mice, of which 35 and 128 miRNAs were potentially down- and up-regulated, respectively. We performed network and pathway analyses of the >1700 potential mRNA targets of the differentially expressed miRNAs using MiRNet, Gene Ontology, Reactome and KEGG analyses. The mRNA targets were over-represented in numerous cellular signalling pathways, including cellular protective responses. In addition, we explored 13 and 29 potential differentially expressed miRNAs to have putative binding sites in the Slc13a1 and Slc26a1 sulfate transporter mRNAs, respectively, and that decreased levels of mir-466k may potentially explain the increased expression of these sulfate transporters in early mouse gestation. Collectively, this study suggests altered expression levels of miRNAs during mouse gestation, which provides pilot data for future investigations into the molecular events that modulate kidney adaptsation to pregnancy.
Collapse
Affiliation(s)
- Soohyun Lee
- Mater Research Institute, University of Queensland, Brisbane, Queensland, Australia
| | - Fergal Thomas Temple
- Mater Research Institute, University of Queensland, Brisbane, Queensland, Australia
| | - Paul Anthony Dawson
- Mater Research Institute, University of Queensland, Brisbane, Queensland, Australia
| |
Collapse
|
5
|
Post A, Minović I, van den Berg E, Eggersdorfer ML, Navis GJ, Geleijnse JM, Gans ROB, van Goor H, Struck J, Franssen CFM, Kema IP, Bakker SJL. Renal sulfate reabsorption in healthy individuals and renal transplant recipients. Physiol Rep 2018; 6:e13670. [PMID: 29671959 PMCID: PMC5907819 DOI: 10.14814/phy2.13670] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 02/28/2018] [Indexed: 11/24/2022] Open
Abstract
Inorganic sulfate is essential for normal cellular function and its homeostasis is primarily regulated in the kidneys. However, little is known about renal sulfate handling in humans and particularly in populations with impaired kidney function such as renal transplant recipients (RTR). Hence, we aimed to assess sulfate reabsorption in kidney donors and RTR. Plasma and urinary sulfate were determined in 671 RTR and in 251 kidney donors. Tubular sulfate reabsorption (TSR) was defined as filtered load minus sulfate excretion and fractional sulfate reabsorption (FSR) was defined as 1-fractional excretion. Linear regression analyses were employed to explore associations of FSR with baseline parameters and to identify the determinants of FSR in RTR. Compared to kidney donors, RTR had significantly lower TSR (15.2 [11.2-19.5] vs. 20.3 [16.7-26.3] μmol/min), and lower FSR (0.56 [0.48-0.64] vs. 0.64 [0.57-0.69]) (all P < 0.001). Kidney donation reduced both TSR and FSR by circa 50% and 25% respectively (both P < 0.001). In RTR and donors, both TSR and FSR associated positively with renal function. In RTR, FSR was independently associated with urinary thiosulfate (β = -0.18; P = 0.002), growth hormone (β = 0.12; P = 0.007), the intakes of alcohol (β = -0.14; P = 0.002), methionine (β = -0.34; P < 0.001), cysteine (β = -0.41; P < 0.001), and vitamin D (β = -0.14; P = 0.009). In conclusion, TSR and FSR are lower in RTR compared to kidney donors and both associated with renal function. Additionally, FSR is determined by various dietary and metabolic factors. Future research should determine the mechanisms behind sulfate handling in humans and the prognostic value of renal sulfate reabsorption in RTR.
Collapse
Affiliation(s)
- Adrian Post
- Department of Internal MedicineUniversity Medical Center GroningenUniversity of GroningenGroningenThe Netherlands
| | - Isidor Minović
- Department of Internal MedicineUniversity Medical Center GroningenUniversity of GroningenGroningenThe Netherlands
- Top Institute Food and NutritionWageningenThe Netherlands
- Department of Laboratory MedicineUniversity Medical Center GroningenUniversity of GroningenGroningenThe Netherlands
| | - Else van den Berg
- Department of Internal MedicineUniversity Medical Center GroningenUniversity of GroningenGroningenThe Netherlands
| | | | - Gerjan J. Navis
- Department of Internal MedicineUniversity Medical Center GroningenUniversity of GroningenGroningenThe Netherlands
| | | | - Reinold O. B. Gans
- Department of Internal MedicineUniversity Medical Center GroningenUniversity of GroningenGroningenThe Netherlands
| | - Harry van Goor
- Department of PathologyUniversity Medical Center GroningenUniversity of GroningenGroningenThe Netherlands
| | | | - Casper F. M. Franssen
- Department of Internal MedicineUniversity Medical Center GroningenUniversity of GroningenGroningenThe Netherlands
| | - Ido P. Kema
- Department of Laboratory MedicineUniversity Medical Center GroningenUniversity of GroningenGroningenThe Netherlands
| | - Stephan J. L. Bakker
- Department of Internal MedicineUniversity Medical Center GroningenUniversity of GroningenGroningenThe Netherlands
- Top Institute Food and NutritionWageningenThe Netherlands
- Transplant Lines Food and Nutrition Biobank and Cohort StudyUniversity Medical Center GroningenUniversity of GroningenGroningenThe Netherlands
| |
Collapse
|
6
|
Dawson PA, Richard K, Perkins A, Zhang Z, Simmons DG. Review: Nutrient sulfate supply from mother to fetus: Placental adaptive responses during human and animal gestation. Placenta 2017; 54:45-51. [PMID: 28089504 DOI: 10.1016/j.placenta.2017.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 12/23/2016] [Accepted: 01/04/2017] [Indexed: 01/20/2023]
Abstract
Nutrient sulfate has numerous roles in mammalian physiology and is essential for healthy fetal growth and development. The fetus has limited capacity to generate sulfate and relies on sulfate supplied from the maternal circulation via placental sulfate transporters. The placenta also has a high sulfate requirement for numerous molecular and cellular functions, including sulfate conjugation (sulfonation) to estrogen and thyroid hormone which leads to their inactivation. Accordingly, the ratio of sulfonated (inactive) to unconjugated (active) hormones modulates endocrine function in fetal, placental and maternal tissues. During pregnancy, there is a marked increase in the expression of genes involved in transport and generation of sulfate in the mouse placenta, in line with increasing fetal and placental demands for sulfate. The maternal circulation also provides a vital reservoir of sulfate for the placenta and fetus, with maternal circulating sulfate levels increasing by 2-fold from mid-gestation. However, despite evidence from animal studies showing the requirement of maternal sulfate supply for placental and fetal physiology, there are no routine clinical measurements of sulfate or consideration of dietary sulfate intake in pregnant women. This is also relevant to certain xenobiotics or pharmacological drugs which when taken by the mother use significant quantities of circulating sulfate for detoxification and clearance, and thereby have the potential to decrease sulfonation capacity in the placenta and fetus. This article will review the physiological adaptations of the placenta for maintaining sulfate homeostasis in the fetus and placenta, with a focus on pathophysiological outcomes in animal models of disturbed sulfate homeostasis.
Collapse
Affiliation(s)
- P A Dawson
- Mater Research Institute, The University of Queensland, Woolloongabba, Australia; School of Biomedical Sciences, The University of Queensland, St. Lucia, Australia.
| | - K Richard
- Conjoint Endocrine Laboratory, Chemical Pathology, Pathology Queensland, Queensland Health, Herston, Australia
| | - A Perkins
- School of Medical Science, Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, Australia
| | - Z Zhang
- Mater Research Institute, The University of Queensland, Woolloongabba, Australia; School of Biomedical Sciences, The University of Queensland, St. Lucia, Australia
| | - D G Simmons
- Mater Research Institute, The University of Queensland, Woolloongabba, Australia; School of Biomedical Sciences, The University of Queensland, St. Lucia, Australia
| |
Collapse
|
7
|
Koning AM, Meijers WC, Minović I, Post A, Feelisch M, Pasch A, Leuvenink HGD, de Boer RA, Bakker SJL, van Goor H. The fate of sulfate in chronic heart failure. Am J Physiol Heart Circ Physiol 2016; 312:H415-H421. [PMID: 27923792 DOI: 10.1152/ajpheart.00645.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 10/24/2016] [Accepted: 11/26/2016] [Indexed: 11/22/2022]
Abstract
New leads to advance our understanding of heart failure (HF) pathophysiology are urgently needed. Previous studies have linked urinary sulfate excretion to a favorable cardiovascular risk profile. Sulfate is not only the end product of hydrogen sulfide metabolism but is also directly involved in various (patho)physiological processes, provoking scientific interest in its renal handling. This study investigates sulfate clearance in chronic HF (CHF) patients and healthy individuals and considers its relationship with disease outcome. Parameters related to renal sulfate handling were determined in and compared between 96 previously characterized CHF patients and sex-matched healthy individuals. Among patients, sulfate clearance was analyzed for associations with clinical and outcome parameters. In CHF patients, plasma sulfate concentrations are significantly higher, whereas 24-h urinary excretion, fractional excretion, and clearance of sulfate are significantly lower, compared with healthy individuals. Among patients, sulfate clearance is independently associated with diuretics use, creatinine clearance and 24-h urinary sodium excretion. Sulfate clearance is associated with favorable disease outcome [hazard ratio per SD increase 0.38 (95% confidence interval 0.23-0.63), P < 0.001]. Although significance was lost after adjustment for creatinine clearance, the decrease of sulfate clearance in patients is independent of this parameter, indicating that sulfate clearance is not merely a reflection of renal function. This exploratory study reveals aberrant sulfate clearance as a potential contributor to CHF pathophysiology, with reduced levels in patients and a positive association with favorable disease outcome. Further research is needed to unravel the nature of its involvement and to determine its potential as a biomarker and target for therapy.NEW & NOTEWORTHY Sulfate clearance is decreased in chronic heart failure patients compared with healthy individuals. Among patients, sulfate clearance is positively associated with favorable disease outcome, i.e., a decreased rehospitalization rate and increased patient survival. Hence, decreased sulfate clearance may be involved in the pathophysiology of heart failure.
Collapse
Affiliation(s)
- Anne M Koning
- Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.,Department of Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Wouter C Meijers
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Isidor Minović
- Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Adrian Post
- Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Martin Feelisch
- Faculty of Medicine, Clinical and Experimental Sciences, University of Southampton and University Hospital Southampton NHS Foundation Trust, and NIHR Biomedical Research Centre, Southampton, United Kingdom; and
| | - Andreas Pasch
- Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Henri G D Leuvenink
- Department of Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Rudolf A de Boer
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Stephan J L Bakker
- Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Harry van Goor
- Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands;
| |
Collapse
|
8
|
Tise CG, Perry JA, Anforth LE, Pavlovich MA, Backman JD, Ryan KA, Lewis JP, O'Connell JR, Yerges-Armstrong LM, Shuldiner AR. From Genotype to Phenotype: Nonsense Variants in SLC13A1 Are Associated with Decreased Serum Sulfate and Increased Serum Aminotransferases. G3 (Bethesda) 2016; 6:2909-18. [PMID: 27412988 DOI: 10.1534/g3.116.032979] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Using genomic applications to glean insights into human biology, we systematically searched for nonsense single nucleotide variants (SNVs) that are rare in the general population but enriched in the Old Order Amish (Amish) due to founder effect. We identified two nonlinked, nonsense SNVs (R12X and W48X) in SLC13A1 (allele frequencies 0.29% and 0.74% in the Amish; enriched 1.2-fold and 3.7-fold, compared to the outbred Caucasian population, respectively). SLC13A1 encodes the apical sodium-sulfate cotransporter (NaS1) responsible for sulfate (re)absorption in the kidneys and intestine. SLC13A1 R12X and W48X were independently associated with a 27.6% (P = 2.7 × 10−8) and 27.3% (P = 6.9 × 10−14) decrease in serum sulfate, respectively (P = 8.8 × 10-20 for carriers of either SLC13A1 nonsense SNV). We further performed the first exome- and genome-wide association study (ExWAS/GWAS) of serum sulfate and identified a missense variant (L348P) in SLC26A1, which encodes the basolateral sulfate-anion transporter (Sat1), that was associated with decreased serum sulfate (P = 4.4 × 10−12). Consistent with sulfate’s role in xenobiotic detoxification and protection against acetaminophen-induced hepatotoxicity, SLC13A1 nonsense SNV carriers had higher aminotransferase levels compared to noncarriers. Furthermore, SLC26A1 L348P was associated with lower whole-body bone mineral density (BMD) and higher serum calcium, consistent with the osteochondrodysplasia exhibited by dogs and sheep with naturally occurring, homozygous, loss-of-function mutations in Slc13a1. This study demonstrates the power and translational potential of systematic identification and characterization of rare, loss-of-function variants and warrants additional studies to better understand the importance of sulfate in human physiology, disease, and drug toxicity.
Collapse
|
9
|
Seneff S, Swanson N, Li C. Aluminum and Glyphosate Can Synergistically Induce Pineal Gland Pathology: Connection to Gut Dysbiosis and Neurological Disease. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/as.2015.61005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
10
|
|
11
|
|
12
|
Abstract
The SLC13 gene family is comprised of five sequence related proteins that are found in animals, plants, yeast and bacteria. Proteins encoded by the SLC13 genes are divided into the following two groups of transporters with distinct anion specificities: the Na(+)-sulfate (NaS) cotransporters and the Na(+)-carboxylate (NaC) cotransporters. Members of this gene family (in ascending order) are: SLC13A1 (NaS1), SLC13A2 (NaC1), SLC13A3 (NaC3), SLC13A4 (NaS2) and SLC13A5 (NaC2). SLC13 proteins encode plasma membrane polypeptides with 8-13 putative transmembrane domains, and are expressed in a variety of tissues. They are all Na(+)-coupled symporters with strong cation preference for Na(+), and insensitive to the stilbene 4, 4'-diisothiocyanatostilbene-2, 2'-disulphonic acid (DIDS). Their Na(+):anion coupling ratio is 3:1, indicative of electrogenic properties. They have a substrate preference for divalent anions, which include tetra-oxyanions for the NaS cotransporters or Krebs cycle intermediates (including mono-, di- and tricarboxylates) for the NaC cotransporters. This review will describe the molecular and cellular mechanisms underlying the biochemical, physiological and structural properties of the SLC13 gene family.
Collapse
Affiliation(s)
- Daniel Markovich
- Molecular Physiology Group, School of Biomedical Sciences, University of Queensland, Brisbane St Lucia, QLD, Australia.
| |
Collapse
|
13
|
Bergeron M, Clémençon B, Hediger M, Markovich D. SLC13 family of Na+-coupled di- and tri-carboxylate/sulfate transporters. Mol Aspects Med 2013; 34:299-312. [DOI: 10.1016/j.mam.2012.12.001] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 11/16/2012] [Indexed: 12/22/2022]
|
14
|
Frick KK, Asplin JR, Favus MJ, Culbertson C, Krieger NS, Bushinsky DA. Increased biological response to 1,25(OH)(2)D(3) in genetic hypercalciuric stone-forming rats. Am J Physiol Renal Physiol 2013; 304:F718-26. [PMID: 23344574 DOI: 10.1152/ajprenal.00645.2012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Genetic hypercalciuric stone-forming (GHS) rats, bred to maximize urine (U) calcium (Ca) excretion, have increased intestinal Ca absorption and bone Ca resorption and reduced renal Ca reabsorption, leading to increased UCa compared with the Sprague-Dawley (SD) rats. GHS rats have increased vitamin D receptors (VDR) at each of these sites, with normal levels of 1,25(OH)(2)D(3) (1,25D), indicating that their VDR is undersaturated with 1,25D. We tested the hypothesis that 1,25D would induce a greater increase in UCa in GHS rats by feeding both strains ample Ca and injecting 1,25D (25 ng · 100 g body wt(-1) · day(-1)) or vehicle for 16 days. With 1,25D, UCa in SD increased from 1.7 ± 0.3 mg/day to 24.4 ± 1.2 (Δ = 22.4 ± 1.5) and increased more in GHS from 10.5 ± 0.7 to 41.9 ± 0.7 (Δ = 29.8 ± 1.8; P = 0.003). To determine the mechanism of the greater increase in UCa in GHS rats, we measured kidney RNA expression of components of renal Ca transport. Expression of transient receptor potential vanilloid (TRPV)5 and calbindin D(28K) were increased similarly in SD + 1,25D and GHS + 1,25D. The Na(+)/Ca(2+) exchanger (NCX1) was increased in GHS + 1,25D. Klotho was decreased in SD + 1,25D and GHS + 1,25D. TRPV6 was increased in SD + 1,25D and increased further in GHS + 1,25D. Claudin 14, 16, and 19, Na/K/2Cl transporter (NKCC2), and secretory K channel (ROMK) did not differ between SD + 1,25D and GHS + 1,25D. Increased UCa with 1,25D in GHS exceeded that of SD, indicating that the increased VDR in GHS induces a greater biological response. This increase in UCa, which must come from the intestine and/or bone, must exceed any effect of 1,25D on TRPV6 or NCX1-mediated renal Ca reabsorption.
Collapse
Affiliation(s)
- Kevin K Frick
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
| | | | | | | | | | | |
Collapse
|
15
|
Zhao X, Onteru SK, Piripi S, Thompson KG, Blair HT, Garrick DJ, Rothschild MF. In a shake of a lamb's tail: using genomics to unravel a cause of chondrodysplasia in Texel sheep. Anim Genet 2012; 43 Suppl 1:9-18. [DOI: 10.1111/j.1365-2052.2011.02304.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- X. Zhao
- Department of Animal Science and Center for Integrated Animal Genomics; Iowa State University; Ames; IA; 50011; USA
| | - S. K. Onteru
- Department of Animal Science and Center for Integrated Animal Genomics; Iowa State University; Ames; IA; 50011; USA
| | | | - K. G. Thompson
- Institute of Veterinary, Animal & Biomedical Sciences; Massey University; Palmerston North; 4474; New Zealand
| | - H. T. Blair
- Institute of Veterinary, Animal & Biomedical Sciences; Massey University; Palmerston North; 4474; New Zealand
| | | | - M. F. Rothschild
- Department of Animal Science and Center for Integrated Animal Genomics; Iowa State University; Ames; IA; 50011; USA
| |
Collapse
|
16
|
Abstract
Anion transporters NaS1 (SLC13A1) and Sat1 (SLC26A1) mediate sulfate (re)absorption across renal proximal tubule and small intestinal epithelia, thereby regulating blood sulfate levels. Disruption of murine NaS1 and Sat1 genes leads to hyposulfatemia and hypersulfaturia. Sat1-null mice also exhibit hyperoxalemia, hyperoxaluria, and calcium oxalate urolithiasis. This review will highlight the current pathophysiological features of NaS1- and Sat1-null mice resulting from alterations in circulating sulfate and oxalate anion levels.
Collapse
Affiliation(s)
- Daniel Markovich
- Molecular Physiology Group, School of Biomedical Sciences, University of Queensland, St. Lucia, Australia.
| |
Collapse
|
17
|
Seneff S, Davidson R, Mascitelli L. Might cholesterol sulfate deficiency contribute to the development of autistic spectrum disorder? Med Hypotheses 2011; 78:213-7. [PMID: 22098722 DOI: 10.1016/j.mehy.2011.10.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 08/20/2011] [Accepted: 10/23/2011] [Indexed: 12/12/2022]
Abstract
Autism is a condition characterized by impaired cognitive and social skills, often associated with compromised immune function. There has been considerable concern recently that the incidence of autism is alarmingly on the rise, especially in Western nations, and environmental factors are increasingly suspected to play a role. In this paper, we propose a novel hypothesis for a principle cause of autism, namely insufficient supply of cholesterol sulfate to the fetus during gestation and the infant postnatally. We hypothesize that main contributory factors are insufficient sun exposure and insufficient dietary sulfur, for both the mother and the affected child. A novel contribution is the theory that endothelial nitric oxide synthase produces not only nitric oxide but also sulfate, and that sulfate production is stimulated by sunlight. We further hypothesize that the sulfur shortage manifests as an impaired immune response, including an increased susceptibility to eczema and asthma. Proposed corrective measures involve increased dietary sulfur intake for both the mother and the child, and increased sun exposure.
Collapse
Affiliation(s)
- Stephanie Seneff
- Department of Electrical Engineering and Computer Science, MIT, Cambridge, MA, USA.
| | | | | |
Collapse
|
18
|
Alpantaki K, Katonis P, Hadjipavlou AG, Spandidos DA, Sourvinos G. Herpes virus infection can cause intervertebral disc degeneration. ACTA ACUST UNITED AC 2011; 93:1253-8. [DOI: 10.1302/0301-620x.93b9.27002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
It has been proposed that intervertebral disc degeneration might be caused by low-grade infection. The purpose of the present study was to assess the incidence of herpes viruses in intervertebral disc specimens from patients with lumbar disc herniation. A polymerase chain reaction based assay was applied to screen for the DNA of eight different herpes viruses in 16 patients and two controls. DNA of at least one herpes virus was detected in 13 specimens (81.25%). Herpes Simplex Virus type-1 (HSV-1) was the most frequently detected virus (56.25%), followed by Cytomegalovirus (CMV) (37.5%). In two patients, co-infection by both HSV-1 and CMV was detected. All samples, including the control specimens, were negative for Herpes Simplex Virus type-2, Varicella Zoster Virus, Epstein Barr Virus, Human Herpes Viruses 6, 7 and 8. The absence of an acute infection was confirmed both at the serological and mRNA level. To our knowledge this is the first unequivocal evidence of the presence of herpes virus DNA in intervertebral disc specimens of patients with lumbar disc herniation suggesting the potential role of herpes viruses as a contributing factor to the pathogenesis of degenerative disc disease.
Collapse
Affiliation(s)
- K. Alpantaki
- University of Crete, Department of Orthopaedics and Trauma, Faculty of Medicine, Heraklion, Crete 71003, Greece
| | - P. Katonis
- University of Crete, Department of Orthopaedics and Trauma, Faculty of Medicine, Heraklion, Crete 71003, Greece
| | - A. G. Hadjipavlou
- University of Crete, Department of Orthopaedics and Trauma, Faculty of Medicine, Heraklion, Crete 71003, Greece
| | - D. A. Spandidos
- University of Crete, Department of Orthopaedics and Trauma, Faculty of Medicine, Heraklion, Crete 71003, Greece
| | - G. Sourvinos
- University of Crete, Department of Orthopaedics and Trauma, Faculty of Medicine, Heraklion, Crete 71003, Greece
| |
Collapse
|
19
|
Abstract
This review will briefly summarize current knowledge on the renal anion transporters sodium-sulfate cotransporter-1 (NaS1; Slc13a1) and sulfate-anion transporter-1 (Sat1; Slc26a1). NaS1 and Sat1 mediate renal proximal tubular sulfate reabsorption and thereby regulate blood sulfate levels. Sat1 also mediates renal oxalate transport and controls blood oxalate levels. Targeted disruption of murine NaS1 and Sat1 leads to hyposulfatemia and hypersulfaturia. Sat1 null mice also exhibit hyperoxalemia, hyperoxaluria, and calcium oxalate urolithiasis. NaS1 and Sat1 null mice also have other phenotypes that result due to changes in blood sulfate and oxalate levels. Experimental data indicate that NaS1 is essential for maintaining sulfate homeostasis, whereas Sat1 controls both sulfate and oxalate homeostasis in vivo.
Collapse
Affiliation(s)
- Daniel Markovich
- Molecular Physiology Group, School of Biomedical Sciences, Univ. of Queensland, St. Lucia, Australia.
| |
Collapse
|
20
|
Markovich D. Physiological roles of mammalian sulfate transporters NaS1 and Sat1. Arch Immunol Ther Exp (Warsz) 2011; 59:113-6. [PMID: 21298488 DOI: 10.1007/s00005-011-0114-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 10/08/2010] [Indexed: 11/29/2022]
Abstract
This review summarizes the physiological roles of the renal sulfate transporters NaS1 (Slc13a1) and Sat1 (Slc26a1). NaS1 and Sat1 encode renal anion transporters that mediate proximal tubular sulfate reabsorption and thereby regulate blood sulfate levels. Targeted disruption of murine NaS1 and Sat1 leads to hyposulfatemia and hypersulfaturia. Sat1 null mice also exhibit hyperoxalemia, hyperoxaluria and calcium oxalate urolithiasis. Dysregulation of NaS1 and Sat1 leads to hypersulfaturia, hyposulfatemia and liver damage. Loss of Sat1 leads additionally to hyperoxaluria with hyperoxalemia, nephrocalcinosis and calcium oxalate urolithiasis. These data indicate that the renal anion transporters NaS1 and Sat1 are essential for sulfate and oxalate homeostasis, respectively.
Collapse
Affiliation(s)
- Daniel Markovich
- School of Biomedical Sciences, University of Queensland, St. Lucia, QLD 4072, Australia.
| |
Collapse
|
21
|
Abstract
The pathophysiology of intervertebral disc degeneration has been extensively studied. Various factors have been suggested as influencing its aetiology, including mechanical factors, such as compressive loading, shear stress and vibration, as well as ageing, genetic, systemic and toxic factors, which can lead to degeneration of the disc through biochemical reactions. How are these factors linked? What is their individual importance? There is no clear evidence indicating whether ageing in the presence of repetitive injury or repetitive injury in the absence of ageing plays a greater role in the degenerative process. Mechanical factors can trigger biochemical reactions which, in turn, may promote the normal biological changes of ageing, which can also be accelerated by genetic factors. Degradation of the molecular structure of the disc during ageing renders it more susceptible to superimposed mechanical injuries. This review supports the theory that degeneration of the disc has a complex multifactorial aetiology. Which factors initiate the events in the degenerative cascade is a question that remains unanswered, but most evidence points to an age-related process influenced primarily by mechanical and genetic factors.
Collapse
Affiliation(s)
- A G Hadjipavlou
- Division of Spine Surgery, University of Texas Medical Branch at Galveston, Texas, USA.
| | | | | | | |
Collapse
|
22
|
Abstract
A 72-h time-course study was conducted to elucidate the physiological mechanism underlying cysteine (Cys) toxicity in chicks beginning at 8-d posthatch. Biochemical markers quantified in plasma and liver samples collected from chicks receiving 30 g/kg excess dietary Cys were compared with baseline measurements from chicks receiving an unsupplemented corn-soybean meal diet over a 72-h feeding period. Concomitant with chick mortality were indices of acute metabolic acidosis, including a rapid increase (P < 0.001) in anion gap that resulted from a reduction (P < 0.001) in plasma HCO(3)(-) of approximately 40% and a 2.8-fold increase (P < 0.001) in plasma sulfate in chicks receiving excess Cys. Additionally, provision of 30 g/kg excess Cys resulted in a 1.5-fold increase (P < 0.05) in hepatic oxidized glutathione compared with the 0-h control time-point. Excess dietary Cys did not affect plasma free Met, but plasma free Cys increased (P < 0.05) from 89 to 107 mumol/L at 12 h and remained elevated through 36 h. Strikingly, ingestion of 30 g/kg excess Cys caused more than a doubling (P < 0.001) of plasma free cystine, the oxidized form of Cys, beginning 12 h after initiating the study, and it remained elevated throughout the 72-h feeding period. Taken together, these data suggest that ingestion of 30 g/kg excess l-Cys causes both acute metabolic acidosis and oxidative stress in young chicks when fed a nutritionally adequate, corn-soybean meal diet.
Collapse
Affiliation(s)
- Ryan N Dilger
- Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
| | | |
Collapse
|
23
|
|
24
|
Abstract
Sulfate is essential for normal cellular function. The kidney plays a major role in sulfate homeostasis. Sulfate is freely filtered and then undergoes net reabsorption in the proximal tubule. The apical membrane Na(+)/sulfate cotransporter NaS1 (SLC13A1) has a major role in mediating proximal tubule sulfate reabsorption, as demonstrated by the findings of hyposulfatemia and hypersulfaturia in Nas1-null mice. The anion exchanger SAT1 (SLC26A1), the founding member of the SLC26 sulfate transporter family, mediates sulfate exit across the basolateral membrane to complete the process of transtubular sulfate reabsorption. Another member of this family, CFEX (SLC26A6), is present at the apical membrane of proximal tubular cells. It also can transport sulfate by anion exchange, which probably mediates backflux of sulfate into the lumen. Knockout mouse studies have demonstrated a major role of CFEX as an apical membrane Cl(-)/oxalate exchanger that contributes to NaCl reabsorption in the proximal tubule. Several additional SLC26 family members mediate sulfate transport and show some level of renal expression (e.g., SLC26A2, SLC26A7, SLC26A11). Their roles in mediating renal tubular sulfate transport are presently unknown. This paper reviews current data available on the function and regulation of three sulfate transporters (NaS1, SAT1, and CFEX) and their physiological roles in the kidney.
Collapse
Affiliation(s)
- Daniel Markovich
- Department of Physiology and Pharmacology, School of Biomedical Sciences, University of Queensland, Brisbane, QLD 4072 Australia.
| | | |
Collapse
|
25
|
Chan D, Song Y, Sham P, Cheung KMC. Genetics of disc degeneration. Eur Spine J 2006; 15 Suppl 3:S317-25. [PMID: 16819621 PMCID: PMC2335375 DOI: 10.1007/s00586-006-0171-3] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 05/19/2006] [Revised: 06/02/2006] [Accepted: 06/07/2006] [Indexed: 01/16/2023]
Abstract
Low back pain from degenerative disc disease (DDD) is one of the most common disorders seen in general and orthopaedic practices. DDD has been attributed to the accumulation of environmental factors, primarily mechanical insults and injuries, imposed on the "normal" aging changes. However, recent studies have shown an association between genetic influences and disc degeneration, with risk of developing DDD quoted to be increased up to six times that of the general population. It is likely that DDD is a complex, multifactorial disease determined by the interplay between gene(s) and the environment. This review focuses on the evidence for genetic disposition, the genes or biological processes that are implicated, and the need to consolidate resources and clarify phenotype definition to take advantage of the new technologies in genetic analysis to enhance our understanding of this condition.
Collapse
Affiliation(s)
- Danny Chan
- Department of Biochemistry, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Youqiang Song
- Department of Biochemistry, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
- Department of Orthopaedics and Traumatology, Queen Mary Hospital, The University of Hong Kong Medical Centre, Pokfulam, Hong Kong SAR, China
- Genome Research Centre, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Pak Sham
- Genome Research Centre, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
- Institute of Psychiatry, London University, London, UK
| | - Kenneth M. C. Cheung
- Department of Orthopaedics and Traumatology, Queen Mary Hospital, The University of Hong Kong Medical Centre, Pokfulam, Hong Kong SAR, China
| |
Collapse
|
26
|
Nakada T, Zandi-Nejad K, Kurita Y, Kudo H, Broumand V, Kwon CY, Mercado A, Mount DB, Hirose S. Roles of Slc13a1 and Slc26a1 sulfate transporters of eel kidney in sulfate homeostasis and osmoregulation in freshwater. Am J Physiol Regul Integr Comp Physiol 2005; 289:R575-R585. [PMID: 15802556 DOI: 10.1152/ajpregu.00725.2004] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sulfate is required for proper cell growth and development of all organisms. We have shown that the renal sulfate transport system has dual roles in euryhaline eel, namely, maintenance of sulfate homeostasis and osmoregulation of body fluids. To clarify the physiological roles of sulfate transporters in teleost fish, we cloned orthologs of the mammalian renal sulfate transporters Slc13a1 (NaSi-1) and Slc26a1 (Sat-1) from eel (Anguilla japonica) and assessed their functional characteristics, tissue localization, and regulated expression. Full-length cDNAs coding for ajSlc13a1 and ajSlc26a1 were isolated from a freshwater eel kidney cDNA library. Functional expression in Xenopus oocytes revealed the expected sulfate transport characteristics; furthermore, both transporters were inhibited by mercuric chloride. Northern blot analysis, in situ hybridization, and immunohistochemistry demonstrated robust apical and basolateral expression of ajSlc13a1 and ajSlc26a1, respectively, within the proximal tubule of freshwater eel kidney. Expression was dramatically reduced after the transfer of eels from freshwater to seawater; the circulating sulfate concentration in eels was in turn markedly elevated in freshwater compared with seawater conditions (19 mM vs. 1 mM). The reabsorption of sulfate via the apical ajSlc13a1 and basolateral ajSlc26a1 transporters may thus contribute to freshwater osmoregulation in euryhaline eels, via the regulation of circulating sulfate concentration.
Collapse
Affiliation(s)
- Tsutomu Nakada
- Dept. of Biological Sciences, Tokyo Institute of Technology, 4259-B-19 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Bolt MJG, Liu W, Qiao G, Kong J, Zheng W, Krausz T, Cs-Szabo G, Sitrin MD, Li YC. Critical role of vitamin D in sulfate homeostasis: regulation of the sodium-sulfate cotransporter by 1,25-dihydroxyvitamin D3. Am J Physiol Endocrinol Metab 2004; 287:E744-9. [PMID: 15165995 DOI: 10.1152/ajpendo.00151.2004] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
As the fourth most abundant anion in the body, sulfate plays an essential role in numerous physiological processes. One key protein involved in transcellular transport of sulfate is the sodium-sulfate cotransporter NaSi-1, and previous studies suggest that vitamin D modulates sulfate homeostasis by regulating NaSi-1 expression. In the present study, we found that, in mice lacking the vitamin D receptor (VDR), NaSi-1 expression in the kidney was reduced by 72% but intestinal NaSi-1 levels remained unchanged. In connection with these findings, urinary sulfate excretion was increased by 42% whereas serum sulfate concentration was reduced by 50% in VDR knockout mice. Moreover, levels of hepatic glutathione and skeletal sulfated proteoglycans were also reduced by 18 and 45%, respectively, in the mutant mice. Similar results were observed in VDR knockout mice after their blood ionized calcium levels and rachitic bone phenotype were normalized by dietary means, indicating that vitamin D regulation of NaSi-1 expression and sulfate metabolism is independent of its role in calcium metabolism. Treatment of wild-type mice with 1,25-dihydroxyvitamin D3 or vitamin D analog markedly stimulated renal NaSi-1 mRNA expression. These data provide strong in vivo evidence that vitamin D plays a critical role in sulfate homeostasis. However, the observation that serum sulfate and skeletal proteoglycan levels in normocalcemic VDR knockout mice remained low in the absence of rickets and osteomalacia suggests that the contribution of sulfate deficiency to development of rickets and osteomalacia is minimal.
Collapse
Affiliation(s)
- Merry J G Bolt
- Department of Medicine, University of Chicago, IL 60637, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Lee A, Markovich D. Characterization of the human renal Na(+)-sulphate cotransporter gene ( NAS1) promoter. Pflugers Arch 2004; 448:490-9. [PMID: 15197597 DOI: 10.1007/s00424-004-1251-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2004] [Accepted: 02/16/2004] [Indexed: 10/26/2022]
Abstract
Sulphate (SO(4)(2-)) plays an essential role during growth, development, and cellular metabolism. Recently, we have isolated the human renal Na(+)-SO(4)(2-) cotransporter (hNaSi-1) that is implicated in the regulation of serum SO(4)(2-) levels. To gain an insight into hNaSi-1 regulation, our aims were to clone and characterize functionally the hNaSi-1 gene ( NAS1) promoter. We PCR-amplified 3742 bp of the NAS1 5'-flanking region, which is 64% AT-rich and contains numerous putative cis-acting elements. The NAS1 transcription start site was mapped to 25 bp upstream from the translation start site. NAS1 promoter truncations fused to luciferase gene constructs transfected into renal LLC-PK1, MDCK and OK cells allowed us to establish that the first 169 bp of the NAS1 promoter are sufficient for basal transcription. Furthermore, the NAS1 promoter conferred responsiveness to the polycyclic aromatic hydrocarbon 3-methylcholanthrene (3-MC), but not to thyroid hormone (T(3)) or vitamin D [1,25-(OH)(2)D(3)]. Site-directed mutagenesis of the NAS1 promoter identified a functional xenobiotic response element at -2,052, which conferred 3-MC responsiveness. The human NAS1 gene promoter is not responsive to Vitamin D or T(3), unlike the mouse Nas1 promoter with which it shares approximately 40% sequence similarity, but is transactivated by 3-MC, suggesting that the control of renal SO(4)(2-) reabsorption via the regulation of NAS1 transcription may be important for maintaining the sulphation potential for kidney polycyclic aromatic hydrocarbon metabolism.
Collapse
Affiliation(s)
- Aven Lee
- Physiology and Pharmacology, School of Biomedical Sciences, University of Queensland, QLD 4072, Brisbane, Australia
| | | |
Collapse
|
29
|
Abstract
The SLC13 gene family consist of five sequence-related members that have been identified in a variety of animals, plants, yeast and bacteria. Proteins encoded by these genes are divided into two functionally unrelated groups: the Na(+)-sulphate (NaS) cotransporters and the Na(+)-carboxylate (NaC) cotransporters. Members of this family include the renal Na(+)-dependent inorganic sulphate transporter-1 (NaSi-1, SLC13A1), the Na(+)-dependent dicarboxylate transporters NaDC-1/SDCT1 (SLC13A2), NaDC-3/SDCT2 (SLC13A3), the sulphate transporter-1 (SUT-1, SLC13A4) and the Na(+)-coupled citrate transporter (NaCT, SLC13A5). The general characteristics of the SLC13 proteins are that they encode multi-spanning proteins with 8-13 transmembrane domains, have a wide tissue distribution with most being expressed in the epithelial cells of the kidney and the gastrointestinal tract. They are Na(+)-coupled symporters, DIDS-insensitive, with strong cation preference for Na(+), with a Na(+):anion coupling ratio of around 3:1 and have a substrate preference for divalent anions, which include tetraoxyanions (for the NaS cotransporters) or Krebs cycle intermediates, including mono-, di-, and tri-carboxylates (for the NaC cotransporters). The purpose of this review is to provide an update on the most recent advances and to summarize the biochemical, physiological and structural aspects of the vertebrate SLC13 gene family.
Collapse
Affiliation(s)
- Daniel Markovich
- Department of Physiology and Pharmacology, School of Biomedical Sciences, University of Queensland, QLD 4072, St. Lucia, Australia.
| | | |
Collapse
|
30
|
Good DW, George T, Watts BA. Aldosterone potentiates 1,25-dihydroxyvitamin D3 action in renal thick ascending limb via a nongenomic, ERK-dependent pathway. Am J Physiol Cell Physiol 2003; 285:C1122-30. [PMID: 12839832 DOI: 10.1152/ajpcell.00125.2003] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Recently, we demonstrated that aldosterone inhibits HCO3- absorption in the rat medullary thick ascending limb (MTAL) via a nongenomic pathway blocked by inhibitors of extracellular signal-regulated kinase (ERK) activation. Here we examined the effects on the MTAL of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], which regulates cell functions through nongenomic mechanisms in nonrenal systems. Addition of 1 nM 1,25(OH)2D3 to the bath decreased HCO3- absorption by 24%, from 15.0 +/- 0.3 to 11.4 +/- 0.5 pmol. min-1. mm-1 (P < 0.001). This inhibition was maximal within 60 min and was eliminated by pretreatment with actinomycin D, cycloheximide, or inhibitors of protein kinase C. In MTAL bathed with 1 nM aldosterone [added 15-20 min before 1,25(OH)2D3], the absolute (5.6 +/- 0.3 vs. 3.6 +/- 0.3 pmol. min-1. mm-1) and fractional (49 +/- 2 vs. 24 +/- 2%) decreases in HCO3- absorption induced by 1,25(OH)2D3 were significantly greater than those in the absence of aldosterone (P < 0.05). The effect of aldosterone to potentiate inhibition by 1,25(OH)2D3 was not affected by spironolactone but was eliminated by the MAPK kinase/ERK inhibitor U-0126. U-0126 did not affect inhibition of HCO3- absorption by 1,25(OH)2D3 alone. Aldosterone induced rapid activation of ERK via a transcription-independent pathway. We conclude that 1) 1,25(OH)2D3 inhibits HCO3- absorption in the MTAL via a genomic pathway involving protein kinase C, which may contribute to 1,25(OH)2D3-induced regulation of urinary net acid and/or Ca2+ excretion and 2) aldosterone potentiates inhibition by 1,25(OH)2D3 through an ERK-dependent, nongenomic pathway. These results identify a novel regulatory interaction whereby aldosterone acts via nongenomic mechanisms to enhance the genomic response to 1,25(OH)2D3. Aldosterone may influence a broad range of biological processes, including epithelial transport, by modifying the response of target tissues to 1,25(OH)2D3 stimulation.
Collapse
Affiliation(s)
- David W Good
- Department of Medicine, 4.200 John Sealy Annex, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555-0562, USA.
| | | | | |
Collapse
|
31
|
Lee A, Beck L, Markovich D. The mouse sulfate anion transporter gene Sat1 (Slc26a1): cloning, tissue distribution, gene structure, functional characterization, and transcriptional regulation thyroid hormone. DNA Cell Biol 2003; 22:19-31. [PMID: 12590734 DOI: 10.1089/104454903321112460] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Sulfate (SO(4)(2-)) is required for bone/cartilage formation and cellular metabolism. sat-1 is a SO(4)(2-) anion transporter expressed on basolateral membranes of renal proximal tubules, and is suggested to play an important role in maintaining SO(4)(2-) homeostasis. As a first step towards studying its tissue-specific expression, hormonal regulation, and in preparation for the generation of knockout mice, we have cloned and characterized the mouse sat-1 cDNA (msat-1), gene (sat1; Slc26a1) and promoter region. msat-1 encodes a 704 amino acid protein (75.4 kDa) with 12 putative transmembrane domains that induce SO(4)(2-) (also oxalate and chloride) transport in Xenopus oocytes. msat-1 mRNA was expressed in kidney, liver, cecum, calvaria, brain, heart, and skeletal muscle. Two distinct transcripts were expressed in kidney and liver due to alternative utilization of the first intron, corresponding to an internal portion of the 5'-untranslated region. The Sat1 gene (~6 kb) consists of 4 exons. Its promoter is ~52% G + C rich and contains a number of well-characterized cis-acting elements, including sequences resembling hormone responsive elements T(3)REs and VDREs. We demonstrate that Sat1 promoter driven basal transcription in OK cells was stimulated by tri-iodothyronine. Site-directed mutagenesis identified an imperfect T(3)RE at -454-bp in the Sat1 promoter to be responsible for this activity. This study represents the first characterization of the structure and regulation of the Sat1 gene encoding a SO(4)(2-)/chloride/oxalate anion transporter.
Collapse
Affiliation(s)
- Aven Lee
- Department of Physiology and Pharmacology, School of Biomedical Sciences, University of Queensland, Brisbane, Queensland, Australia
| | | | | |
Collapse
|
32
|
Abstract
The mechanisms and control of transepithelial inorganic sulfate (Si) transport by primary cultures of chick renal proximal tubule monolayers in Ussing chambers were determined. The competitive anion, S2 O 3 2- (5 mM), reduced both unidirectional reabsorptive and secretory fluxes and net Si reabsorption with no effect on electrophysiological properties. The carbonic anhydrase (CA) inhibitor ethoxzolamide decreased net Si reabsorption approximately 45%. CAII protein and activity were detected in isolated chick proximal tubules by immunoblots and biochemical assay, respectively. Cortisol reduced net Si reabsorption up to approximately 50% in a concentration-dependent manner. Thyroid hormone increased net Si reabsorption threefold in 24 h, and parathyroid hormone (PTH) acutely stimulated net Si reabsorption approximately 45%. These data indicate that CA participates in avian proximal tubule active transepithelial Si reabsorption, which cortisol directly inhibits and T3 and PTH directly stimulate.
Collapse
Affiliation(s)
- Paul L Dudas
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269, USA
| | | |
Collapse
|
33
|
Abstract
All cells require inorganic sulfate for normal function. Sulfate is among the most important macronutrients in cells and is the fourth most abundant anion in human plasma (300 microM). Sulfate is the major sulfur source in many organisms, and because it is a hydrophilic anion that cannot passively cross the lipid bilayer of cell membranes, all cells require a mechanism for sulfate influx and efflux to ensure an optimal supply of sulfate in the body. The class of proteins involved in moving sulfate into or out of cells is called sulfate transporters. To date, numerous sulfate transporters have been identified in tissues and cells from many origins. These include the renal sulfate transporters NaSi-1 and sat-1, the ubiquitously expressed diastrophic dysplasia sulfate transporter DTDST, the intestinal sulfate transporter DRA that is linked to congenital chloride diarrhea, and the erythrocyte anion exchanger AE1. These transporters have only been isolated in the last 10-15 years, and their physiological roles and contributions to body sulfate homeostasis are just now beginning to be determined. This review focuses on the structural and functional properties of mammalian sulfate transporters and highlights some of regulatory mechanisms that control their expression in vivo, under normal physiological and pathophysiological states.
Collapse
Affiliation(s)
- D Markovich
- Department of Physiology and Pharmacology, University of Queensland, Brisbane, Queensland, Australia.
| |
Collapse
|
34
|
Abstract
BACKGROUND Recent studies have shown that renal expression of 25-hydroxyvitamin D3-1alpha-hydroxylase (1alpha-OHase) is not restricted to proximal tubules. To investigate the significance of this expression, we characterized the regulation of 1alpha-OHase expression and activity in a human cortical collecting duct cell line (HCD). METHODS Expression of 1alpha-OHase mRNA and protein was assessed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analyses. Enzyme activity was quantified using 25-hydroxyvitamin D3 as the substrate; conversion to 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] and 24,25-dihydroxyvitamin D3 was then determined by thin-layer chromatography. RESULTS HCD cells expressed mRNA and protein for 1alpha-OHase. However, basal 1,25(OH)2D3 production was lower than that observed in proximal tubule HKC-8 cells. In both cell lines, synthesis of 1,25(OH)2D3 was increased by forskolin, parathyroid hormone, and low calcium medium. Conversely, treatment with 1,25(OH)2D3 itself decreased 1alpha-OHase activity. This effect was more pronounced in HCD cells, which also demonstrated significantly higher levels of 24-hydroxylase activity. The most striking induction of 1alpha-OHase activity was observed in the HCD cells following incubation with lipopolysaccharide, which was coincident with the expression of mRNA for both CD14 and Toll-like receptor 4. CONCLUSIONS These results highlight the capacity for synthesis of 1,25(OH)2D3 in cells from more distal areas of the nephron. However, more sensitive feedback regulation and immune induction of 1alpha-OHase in the HCD cells suggest a more localized role for 1,25(OH)2D3 production in the distal nephron.
Collapse
Affiliation(s)
- R Bland
- Division of Medical Sciences, The University of Birmingham, Queen Elizabeth Hospital, Birmingham, England, United Kingdom
| | | | | | | | | | | |
Collapse
|
35
|
Abstract
The renal proximal tubular reabsorption of sulfate plays an important role in the maintenance of sulfate homeostasis. Two different renal sulfate transport systems have been identified and characterized at the molecular level in the past few years: NaSi-1 and Sat-1. NaSi-1 belongs to a Na(+)-coupled transporter family comprising the Na(+)-dicarboxylate transporters and the recently characterized SUT1 sulfate transporter. NaSi-1 is a Na(+)-sulfate cotransporter located exclusively in the brush border membrane of renal proximal tubular and ileal cells. Recently, NaSi-1 was shown to be regulated at the protein and mRNA level by a number of factors, such as vitamin D, dietary sulfate, glucocorticoids and thyroid hormones, which are known to modulate sulfate reabsorption in vivo. The second member of renal sulfate transporters, denoted Sat-1, belongs to a family of Na+-independent sulfate transporter family comprising the DTDST, DRA and PDS genes. Sat-1 is a sulfate/bicarbonate-oxalate exchanger located at the basolateral membrane of proximal tubular epithelial cells and canalicular surface of hepatic cells. Contrary to NaSi-1, no physiological factor has been found to date to regulate Sat-1 gene expression. Both NaSi-1 and Sat-1 transporter activities are implicated in pathophysiological states such as heavy metal intoxication and chronic renal failure. This review focuses on recent developments in the molecular characterization of NaSi-1 and Sat-1 and the mechanisms involved in their regulation.
Collapse
Affiliation(s)
- L Beck
- INSERM U 426 and Institut Fédératif de Recherche Cellules Epithéliales, Faculté de Médecine Xavier Bichat, Paris, France
| | | |
Collapse
|
36
|
Fernandes I, Laouari D, Tutt P, Hampson G, Friedlander G, Silve C. Sulfate homeostasis, NaSi-1 cotransporter, and SAT-1 exchanger expression in chronic renal failure in rats. Kidney Int 2001; 59:210-21. [PMID: 11135073 DOI: 10.1046/j.1523-1755.2001.00481.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND It is known that hypersulfatemia, like hyperphosphatemia, occurs in chronic renal failure (CRF). The aim of this study was to assess the effects of CRF on sulfate homeostasis and on sodium sulfate cotransport (NaSi-1) and sulfate/oxalate-bicarbonate exchanger (Sat-1) expression in the kidney. In addition, sulfate homeostasis was compared with phosphate homeostasis. METHODS Experimental studies were performed in adult male rats at three and six weeks after 80% subtotal nephrectomy (Nx) or sham-operation (S) (N = 9 per group). Transporter protein and mRNA expressions were measured by Western blot and RNase protection assay (RPA), respectively. Results were quantitated by densitometric scanning (Western) and electronic autoradiography (RPA), and were expressed in densitometric units (DUs; Western) and cpm (RPA). RESULTS Creatinine clearance was lower in Nx-3 compared with S-3 rats (0.23 vs. 0.51 mL/min/100 g body weight, P < 0.001) and was further impaired in Nx-6 rats (0.15 vs. 0.48, P < 0.001). Sulfatemia was significantly higher in Nx-3 rats (1.08 vs. 0.84 mmol/L, P < 0.05) and further increased in Nx-6 rats (1.42 vs. 0.90 mmol/L, P < 0.01). Fractional sulfate excretion (FESO4) was increased by twofold in Nx-3 and Nx-6 rats compared with corresponding S rats. Phosphatemia did not differ between Nx-3 rats and controls, but was increased in Nx-6 rats (P < 0.01). Total amounts of both NaSi-1 and Sat-1 proteins were significantly decreased in both Nx-3 and Nx-6 rats when compared with controls. However, NaSi-1 protein and mRNA densities did not significantly change in Nx-3 rats, but were significantly increased in Nx-6 rats when compared with controls (4.8 vs. 3.7 DU/microg protein, P < 0.05, and 7.1 vs. 2.8 cpm/microg RNA, P < 0.01, respectively, for protein and mRNA). In contrast to NaSi-1, Sat-1 protein density was significantly decreased both in Nx-3 (2.9 vs. 3.6 DU/microg protein, P < 0.05) and Nx-6 rats (2.4 vs. 3.4 DU/microg protein, P < 0.05), and Sat-1 mRNA density significantly decreased in Nx-6 rats (10.7 vs. 14.7 cpm/microg RNA, P < 0.05). Na-PO4 cotransporter (NaPi-2) protein total abundance and density were decreased at three and six weeks in Nx rats. CONCLUSIONS These results demonstrate that both NaSi-1 and Sat-1 total protein abundances are decreased in CRF, which may contribute to the increase in fractional sulfate excretion. Strikingly, NaSi-1 density was not decreased in CRF three weeks after Nx, and furthermore, increased six weeks after Nx, in contrast to NaPi-2 density, which was decreased at both times. The significance of this difference remains to be determined, but may explain why hypersulfatemia occurs earlier than hyperphosphatemia in CRF.
Collapse
Affiliation(s)
- I Fernandes
- INSERM U 426 and Institut Fédératif de Recherche "Cellules Epithéliales," Faculté de Médecine Xavier Bichat, Paris, France
| | | | | | | | | | | |
Collapse
|
37
|
Lee A, Beck L, Markovich D. The human renal sodium sulfate cotransporter (SLC13A1; hNaSi-1) cDNA and gene: organization, chromosomal localization, and functional characterization. Genomics 2000; 70:354-63. [PMID: 11161786 DOI: 10.1006/geno.2000.6404] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sulfate plays an essential role during growth, development, bone/cartilage formation, and cellular metabolism. In this study, we have determined the structure of the human Na+-sulfate cotransporter (hNaSi-1) cDNA (Human Genome Nomenclature Committee-approved symbol SLC13A1) and gene (NAS1). hNaSi-1 encodes a protein of 595 amino acids with 13 putative transmembrane domains. hNaSi-1 mRNA expression was exclusive to the human kidney. Expression of hNaSi-1 protein in Xenopus oocytes demonstrated a high-affinity Na+-sulfate cotransporter that was inhibited by selenate, thiosulfate, molybdate, tungstate, citrate, and succinate. Antisense inhibition experiments suggest hNaSi-1 to represent the major Na+-sulfate cotransporter in the human kidney. NAS1 was localized on human chromosome 7, mapped to 7q31-q32, near the sulfate transporter genes, DRA and SUT-1. The NAS1 gene contains 15 exons, spanning over 83 kb in length. Knowledge of the structure, function, and chromosomal localization of hNaSi-1 will permit the screening of NAS1 mutations in humans with disorders in renal sulfate reabsorption and homeostasis.
Collapse
Affiliation(s)
- A Lee
- Department of Physiology and Pharmacology, University of Queensland, Brisbane, Queensland, 4072, Australia
| | | | | |
Collapse
|
38
|
Abstract
Serum sulfate concentrations are elevated in infants, young children, and pregnant women due, at least in part, to increased renal sulfate reabsorption. Little is known about the effects of hormones, particularly those involved in growth, development, and pregnancy, on renal sulfate reabsorption. The objective of this investigation was to examine the effects of growth hormone (GH), insulin-like growth factor 1 (IGF-1), progesterone (PG), and 17beta-estradiol (EST) on renal sodium/sulfate co-transport. 35S-sulfate uptake was determined in Madin-Darby canine kidney (MDCK)/NaSi-1 cells (MDCK cells that have been stably transfected with rat sodium/sulfate co-transporter (NaSi-1) cDNA) and in opossum kidney (OK) cells. NaSi-1 mRNA was determined by RT-PCR and protein levels by ELISA. GH (0.1 nM) significantly increased the sodium/sulfate co-transport in MDCK/NaSi-1 cells up to 35%. IGF-1 induced a concentration-related stimulation of the sodium/sulfate co-transport with a maximal response observed at 1000 nM (59% increase). Sodium-dependent sulfate uptake was significantly increased when cells were preincubated with 10 nM PG, 10 nM EST, or 10 nM PG/10 nM EST up to 41%, 46%, or 39%, respectively. OK cells exhibited endogenous sodium-dependent sulfate transport; significantly increased sodium/sulfate co-transport was also observed in OK cells that were preincubated with GH, IGF-1, and PG/EST, although not with EST alone. The NaSi-1 mRNA and NaSi-1 protein levels were significantly increased in MDCK/NaSi-1 cells treated with 0.1 nM GH, 100 nM IGF-1, 10 nM PG, and/or 10 nM EST compared with control. These results suggest that the increased renal sulfate reabsorption that occurs in neonates, young and pregnant humans, and animals could be mediated by the increased steady-state levels of NaSi-1 mRNA produced by the higher plasma concentrations of GH, IGF-1, or PG/EST.
Collapse
Affiliation(s)
- H J Lee
- Department of Pharmaceutics, School of Pharmacy, State University of New York at Buffalo, Amherst, New York 14260, USA
| | | | | | | | | |
Collapse
|
39
|
Abstract
Although inorganic sulfate is an essential and ubiquitous anion in human biology, it is infrequently assayed in clinical chemistry today. Serum sulfate is difficult to measure accurately without resorting to physicochemical methods, such as ion chromatography, although many other techniques have been described. It is strongly influenced by a variety of physiological factors, including age, diet, pregnancy, and drug ingestion. Urinary excretion is the principal mechanism of disposal for the excess sulfate produced by sulfur amino acid oxidation, and the kidney is the primary site of regulation. In renal failure, sulfoesters accumulate and hypersulfatemia contributes directly to the unmeasured anion gap characteristic of the condition. In contrast, sulfate in urine is readily assayed by a number of means, particularly nephelometry after precipitation as a barium salt. Sulfate is most commonly assayed today as part of the clinical workup for nephrolithiasis, because sulfate is a major contributor to the ionic strength of urine and alters the equilibrium constants governing saturation and precipitation of calcium salts. Total sulfate deficiency has hitherto not been described, although genetic defects in sulfate transporters have been associated recently with congenital osteochondrodystrophies that may be lethal. New insights into sulfate transport and its hormonal regulation may lead to new clinical applications of sulfate analysis in the future.
Collapse
Affiliation(s)
- D E Cole
- Department of Laboratory Medicine and Pathobiology, University of Toronto, ON.
| | | |
Collapse
|
40
|
Abstract
Inorganic sulfate is an important physiological anion that is a required cofactor for sulfate conjugation reactions of both endogenous and exogenous compounds. It is necessary for the detoxification of xenobiotics and endogenous compounds (catecholamines, steroids, bile acids), for the synthesis of structural components of membranes and tissues (sulfated glycosaminoglycans), and for the biologic activity of endogenous compounds (heparin and cholecystokinin). Inorganic sulfate homeostasis is largely maintained by reabsorption in the renal proximal tubule. Sodium-dependent sulfate cotransport in the brush border membrane is of primary importance in the regulation of plasma inorganic sulfate concentrations. Altered renal reabsorption of sulfate has been observed under different physiological (age, pregnancy, low dietary intake), pathological (hypothyroidism, trace metal excess), and pharmacological conditions (treatment with nonsteroidal antiinflammatory agents). The recent identification of the sulfate transporter genes has allowed the investigation of the molecular mechanisms of altered sulfate transport. Although the regulation of sulfate homeostasis is not fully understood, recent investigations have explored the cellular mechanisms of some of these alterations. In this review, the physiological importance of inorganic sulfate, the availability of this anion, and the regulation of sulfate homeostasis are discussed.
Collapse
Affiliation(s)
- M E Morris
- Department of Pharmaceutics, State University of New York at Buffalo, Amherst 14260, USA
| | | |
Collapse
|
41
|
Affiliation(s)
- D Markovich
- Department of Physiology and Pharmacology, The University of Queensland, Brisbane, Australia.
| |
Collapse
|
42
|
Affiliation(s)
- I Forster
- Physiological Institute, University of Zurich, Switzerland
| | | | | |
Collapse
|
43
|
Beck L, Markovich D. The mouse Na(+)-sulfate cotransporter gene Nas1. Cloning, tissue distribution, gene structure, chromosomal assignment, and transcriptional regulation by vitamin D. J Biol Chem 2000; 275:11880-90. [PMID: 10766815 DOI: 10.1074/jbc.275.16.11880] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
NaSi-1 is a Na(+)-sulfate cotransporter expressed on the apical membrane of the renal proximal tubule and plays an important role in sulfate reabsorption. To understand the molecular mechanisms that mediate the regulation of NaSi-1, we have isolated and characterized the mouse NaSi-1 cDNA (mNaSi-1), gene (Nas1), and promoter region and determined Nas1 chromosomal localization. The mNaSi-1 cDNA encodes a protein of 594 amino acids with 13 putative transmembrane segments, inducing high affinity Na(+)-dependent transport of sulfate in Xenopus oocytes. Three different mNaSi-1 transcripts derived from alternative polyadenylation and splicing were identified in kidney and intestine. The Nas1 gene is a single copy gene comprising 15 exons spread over 75 kilobase pairs that maps to mouse chromosome 6. Transcription initiation occurs from a single site, 29 base pairs downstream to a TATA box-like sequence. The promoter is AT-rich (61%), contains a number of well characterized cis-acting elements, and can drive basal transcriptional activity in opossum kidney cells but not in COS-1 or NIH3T3 cells. We demonstrated that 1,25-dihydroxyvitamin D(3) stimulated the transcriptional activity of the Nas1 promoter in transiently transfected opossum kidney cells. This study represents the first characterization of the genomic organization of a Na(+)-sulfate cotransporter gene. It also provides the basis for a detailed analysis of Nas1 gene regulation and the tools required for assessing Nas1 role in sulfate homeostasis using targeted gene manipulation in mice.
Collapse
Affiliation(s)
- L Beck
- Department of Physiology and Pharmacology, the University of Queensland, Brisbane, Queensland 4072, Australia
| | | |
Collapse
|
44
|
Bland R, Zehnder D, Hewison M. Expression of 25-hydroxyvitamin D3-1alpha-hydroxylase along the nephron: new insights into renal vitamin D metabolism. Curr Opin Nephrol Hypertens 2000; 9:17-22. [PMID: 10654820 DOI: 10.1097/00041552-200001000-00004] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Renal synthesis of the active form of vitamin D, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], is a pivotal step in calcium and phosphate homeostasis. Production of 1,25(OH)2D3 is catalyzed by the mitchondrial cytochrome P450, 25-hydroxyvitamin D3-1alpha-hydroxylase (1alpha-HYD). As a consequence of the tight regulation of vitamin D metabolism during normal physiology, studies of the expression and regulation of 1alpha-HYD have proved remarkably difficult. However, the recent cloning of the gene for 1alpha-HYD has enabled a more comprehensive analysis of the tissue distribution of 1alpha-HYD, as well as the mechanisms involved in controlling 1,25(OH)2D3 production. In particular, an understanding of site-specific expression and regulation of 1alpha-HYD along the nephron might help to elucidate a more versatile role for 1,25(OH)2D3 in renal physiology.
Collapse
Affiliation(s)
- R Bland
- Division of Medical Sciences, The University of Birmingham, UK
| | | | | |
Collapse
|
45
|
Prinz H, Lavie A, Scheidig AJ, Spangenberg O, Konrad M. Binding of nucleotides to guanylate kinase, p21(ras), and nucleoside-diphosphate kinase studied by nano-electrospray mass spectrometry. J Biol Chem 1999; 274:35337-42. [PMID: 10585400 DOI: 10.1074/jbc.274.50.35337] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The binding of nucleotides to three different nucleotide-binding proteins and to a control protein was studied by means of nano-electrospray mass spectrometry applied to aqueous nondenaturing solutions. The method leads to unambiguous identification of enzyme complexes with substrates and products but does not allow the determination of dissociation constants or even stoichiometries relevant to the binding in solution. For guanylate kinase (EC 2.7.4. 8), the transfer of HPO(3) between nucleotides was observed whenever a ternary complex with adenylate or guanylate nucleotides was formed. Guanosine 5'-tetraphosphate was generated after prolonged incubation with GDP or GTP. Mg(2+) binding was considerably enhanced in functional high affinity complexes, such as observed between guanylate kinase and its bisubstrate inhibitor P(1)-(5'-guanosyl)-P(5)-(5'-adenosyl) pentaphosphate or with the tight nucleotide-binding protein p21(ras) and GDP. Nucleoside-diphosphate kinase (EC 2.7.4.6) itself was phosphorylated in accordance to its known ping-pong mechanism. All nucleotide-binding proteins were shown to bind sulfate (SO(4)(2-)) with presumably high affinity and slow exchange rate. The binding of phosphate (PO(4)(3-)) could be inferred indirectly from competition with SO(4)(2-).
Collapse
Affiliation(s)
- H Prinz
- Max-Planck-Institut für Molekulare Physiologie, Otto-Hahn-Str. 11, D-44227 Dortmund, Germany.
| | | | | | | | | |
Collapse
|
46
|
Puttaparthi K, Markovich D, Halaihel N, Wilson P, Zajicek HK, Wang H, Biber J, Murer H, Rogers T, Levi M. Metabolic acidosis regulates rat renal Na-Si cotransport activity. Am J Physiol 1999; 276:C1398-404. [PMID: 10362603 DOI: 10.1152/ajpcell.1999.276.6.c1398] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recently, we cloned a cDNA (NaSi-1) localized to rat renal proximal tubules and encoding the brush-border membrane (BBM) Na gradient-dependent inorganic sulfate (Si) transport protein (Na-Si cotransporter). The purpose of the present study was to determine the effect of metabolic acidosis (MA) on Na-Si cotransport activity and NaSi-1 protein and mRNA expression. In rats with MA for 24 h (but not 6 or 12 h), there was a significant increase in the fractional excretion of Si, which was associated with a 2.4-fold decrease in BBM Na-Si cotransport activity. The decrease in Na-Si cotransport correlated with a 2.8-fold decrease in BBM NaSi-1 protein abundance and a 2.2-fold decrease in cortical NaSi-1 mRNA abundance. The inhibitory effect of MA on BBM Na-Si cotransport was also sustained in rats with chronic (10 days) MA. In addition, in Xenopus laevis oocytes injected with mRNA from kidney cortex, there was a significant reduction in the induced Na-Si cotransport in rats with MA compared with control rats, suggesting that MA causes a decrease in the abundance of functional mRNA encoding the NaSi-1 cotransporter. These findings indicate that MA reduces Si reabsorption by causing decreases in BBM Na-Si cotransport activity and that decreases in the expression of NaSi-1 protein and mRNA abundance, at least in part, play an important role in the inhibition of Na-Si cotransport activity during MA.
Collapse
Affiliation(s)
- K Puttaparthi
- Department of Internal Medicine, University of Texas Southwestern Medical Center and Department of Veterans Affairs Medical Center, Dallas, Texas 75216, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Abstract
The active, hormonal form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) has numerous pleiotropic actions including the regulation of calcium homeostasis, control of bone cell differentiation and modification of immune responses. Synthesis of 1,25(OH)2D3 from the major circulating metabolite, 25-hydroxyvitamin D3 (25(OH)D3), is catalysed by the mitochondrial cytochrome P450 enzyme 25-hydroxyvitamin D-1alpha-hydroxylase (1alpha-HYD). Although 1alpha-HYD activity has been demonstrated at several ectopic sites, circulating levels of 1,25(OH)2D3 appear to reflect the expression of this enzyme in the kidney. The tight regulation of 1alpha-HYD in both renal and ectopic tissues has made studies of the expression and regulation of this enzyme remarkably difficult. However, the recent cloning of mouse, rat and human cDNAs for 1alpha-HYD has stimulated renewed interest in the molecular endocrinology of 1,25(OH)2D3 production. Analysis of the 1alpha-HYD sequence has revealed homology with the liver enzyme vitamin D-25-hydroxylase, and the ubiquitously expressed vitamin D-24-hydroxylase. Furthermore, mutations causing the inherited disorder vitamin D-dependent rickets type 1, also known as pseudo-vitamin D deficiency rickets have been described for the 1alpha-HYD gene and these have been mapped to chromosome 12q14 by linkage analysis. The availability of sequence information for the 1alpha-HYD gene has also facilitated the development of new molecular tools which will help to clarify key functions of the enzyme. Specific issues such as tissue distribution and regulatory pathways are discussed in this review, with particular emphasis on the role of 1alpha-HYD in renal calcium/phosphate homeostasis.
Collapse
Affiliation(s)
- D Zehnder
- Institute of Clinical Research, The Queen Elizabeth Hospital, The University of Birmingham, UK
| | | |
Collapse
|
48
|
Abstract
This review deals with the separation mechanisms applied to the separation of inorganic anions by capillary electrophoresis (CE) techniques. It covers various CE techniques that are suitable for the separation and/or determination of inorganic anions in various matrices, including capillary zone electrophoresis, micellar electrokinetic chromatography, electrochromatography and capillary isotachophoresis. Detection and sample preparation techniques used in CE separations are also reviewed. An extensive part of this review deals with applications of CE techniques in various fields (environmental, food and plant materials, biological and biomedical, technical materials and industrial processes). Attention is paid to speciations of anions of arsenic, selenium, chromium, phosphorus, sulfur and halogen elements by CE.
Collapse
Affiliation(s)
- D Kaniansky
- Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University, Bratislava, Slovak Republic
| | | | | | | |
Collapse
|
49
|
Abstract
Decreased serum sulfate concentrations are observed in hypothyroid patients. However, the mechanism involved in thyroid hormone-induced alterations of renal sulfate homeostasis is unknown. The objectives of this investigation were to determine the effect of 6-propyl-2-thiouracil (PTU)-induced hypothyroidism in rats on 1) the in vivo serum concentrations, renal clearance, and renal reabsorption of sulfate, 2) the in vitro renal transport in brush-border membrane (BBM) and basolateral membrane (BLM) vesicles, and 3) the cellular mechanism of the hypothyroid-induced alteration in sulfate renal transport. Serum sulfate concentrations, renal fractional reabsorption of sulfate, and creatinine clearance were decreased significantly in the hypothyroid group. The Vmax values for sodium-sulfate cotransport in BBM were significantly decreased in the kidney cortex from the hypothyroid animals (0.90 +/- 0.31 vs. 0.49 +/- 0.08 nmol. mg-1. 10 s-1, n = 5-6, P < 0.05) without changes in Km. There were no significant differences in Vmax and Km for sulfate/anion exchange transport in BLM. Sodium-dependent sulfate transporter (NaSi-1) mRNA and protein levels were significantly lower in the kidney cortex from hypothyroid rats. Hypothyroidism did not alter the membrane motional order (fluidity) in BBM and BLM, which indicates that the changes in the membrane fluidity do not represent the mechanism for the altered renal transport. These results demonstrate that PTU-induced hypothyroidism decreases sodium-sulfate cotransport by downregulation of the NaSi-1 gene.
Collapse
Affiliation(s)
- K Sagawa
- Department of Pharmaceutics, State University of New York at Buffalo, Amherst, New York 14260, USA
| | | | | |
Collapse
|