title: Ablation of the Stimulatory G Protein α-Subunit in Renal Proximal Tubules Leads to Parathyroid Hormone-Resistance With Increased Renal Cyp24a1 mRNA Abundance and Reduced Serum 1,25-Dihydroxyvitamin D.
abstract: PTH regulates serum calcium, phosphate, and 1,25-dihydroxyvitamin D (1,25(OH)2D) levels by acting on bone and kidney. In renal proximal tubules (PTs), PTH inhibits reabsorption of phosphate and stimulates the synthesis of 1,25(OH)2D. The PTH receptor couples to multiple G proteins. We here ablated the α-subunit of the stimulatory G protein (Gsα) in mouse PTs by using Cre recombinase driven by the promoter of type-2 sodium-glucose cotransporter (Gsα(Sglt2KO) mice). Gsα(Sglt2KO) mice were normophosphatemic but displayed, relative to controls, hypocalcemia (1.19 ±0.01 vs 1.23 ±0.01 mmol/L; P < .05), reduced serum 1,25(OH)2D (59.3 ±7.0 vs 102.5 ±12.2 pmol/L; P < .05), and elevated serum PTH (834 ±133 vs 438 ±59 pg/mL; P < .05). PTH-induced elevation in urinary cAMP excretion was blunted in Gsα(Sglt2KO) mice (2- vs 4-fold over baseline in controls; P < .05). Relative to baseline in controls, PTH-induced reduction in serum phosphate tended to be blunted in Gsα(Sglt2KO) mice (-0.39 ±0.33 vs -1.34 ±0.36 mg/dL; P = .07). Gsα(Sglt2KO) mice showed elevated renal vitamin D 24-hydroxylase and bone fibroblast growth factor-23 (FGF23) mRNA abundance (∼3.4- and ∼11-fold over controls, respectively; P < .05) and tended to have elevated serum FGF23 (829 ±76 vs 632 ±60 pg/mL in controls; P = .07). Heterozygous mice having constitutive ablation of the maternal Gsα allele (E1(m-/+)) (model of pseudohypoparathyroidism type-Ia), in which Gsα levels in PT are reduced, also exhibited elevated serum FGF23 (474 ±20 vs 374 ±27 pg/mL in controls; P < .05). Our findings indicate that Gsα is required in PTs for suppressing renal vitamin D 24-hydroxylase mRNA levels and for maintaining normal serum 1,25(OH)2D.
authors.affiliation: Endocrine Unit (Z.Y., Q.H., C.A., H.J., M.B.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Department of Endodontics (C.A.), Gülhane Military Medical Academy, 06018 Ankara, Turkey; Faculty of Medicine (I.R., M.T.), Université de Nice Sophia Antipolis, 06107 Nice, France; Metabolic Diseases Branch (M.C., L.S.W.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Program in Membrane Biology (V.M.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Endocrine Unit (Z.Y., Q.H., C.A., H.J., M.B.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Department of Endodontics (C.A.), Gülhane Military Medical Academy, 06018 Ankara, Turkey; Faculty of Medicine (I.R., M.T.), Université de Nice Sophia Antipolis, 06107 Nice, France; Metabolic Diseases Branch (M.C., L.S.W.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Program in Membrane Biology (V.M.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114.
authors.forename: Qing
authors.initials: Q
authors.lastname: He
authors.affiliation: Endocrine Unit (Z.Y., Q.H., C.A., H.J., M.B.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Department of Endodontics (C.A.), Gülhane Military Medical Academy, 06018 Ankara, Turkey; Faculty of Medicine (I.R., M.T.), Université de Nice Sophia Antipolis, 06107 Nice, France; Metabolic Diseases Branch (M.C., L.S.W.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Program in Membrane Biology (V.M.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114.
authors.forename: Cumhur
authors.initials: C
authors.lastname: Aydin
authors.affiliation: Endocrine Unit (Z.Y., Q.H., C.A., H.J., M.B.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Department of Endodontics (C.A.), Gülhane Military Medical Academy, 06018 Ankara, Turkey; Faculty of Medicine (I.R., M.T.), Université de Nice Sophia Antipolis, 06107 Nice, France; Metabolic Diseases Branch (M.C., L.S.W.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Program in Membrane Biology (V.M.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Rubera
authors.affiliation: Endocrine Unit (Z.Y., Q.H., C.A., H.J., M.B.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Department of Endodontics (C.A.), Gülhane Military Medical Academy, 06018 Ankara, Turkey; Faculty of Medicine (I.R., M.T.), Université de Nice Sophia Antipolis, 06107 Nice, France; Metabolic Diseases Branch (M.C., L.S.W.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Program in Membrane Biology (V.M.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114.
authors.forename: Michel
authors.initials: M
authors.lastname: Tauc
authors.affiliation: Endocrine Unit (Z.Y., Q.H., C.A., H.J., M.B.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Department of Endodontics (C.A.), Gülhane Military Medical Academy, 06018 Ankara, Turkey; Faculty of Medicine (I.R., M.T.), Université de Nice Sophia Antipolis, 06107 Nice, France; Metabolic Diseases Branch (M.C., L.S.W.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Program in Membrane Biology (V.M.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114.
authors.forename: Min
authors.initials: M
authors.lastname: Chen
authors.affiliation: Endocrine Unit (Z.Y., Q.H., C.A., H.J., M.B.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Department of Endodontics (C.A.), Gülhane Military Medical Academy, 06018 Ankara, Turkey; Faculty of Medicine (I.R., M.T.), Université de Nice Sophia Antipolis, 06107 Nice, France; Metabolic Diseases Branch (M.C., L.S.W.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Program in Membrane Biology (V.M.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114.
authors.forename: Lee S
authors.initials: LS
authors.lastname: Weinstein
authors.affiliation: Endocrine Unit (Z.Y., Q.H., C.A., H.J., M.B.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Department of Endodontics (C.A.), Gülhane Military Medical Academy, 06018 Ankara, Turkey; Faculty of Medicine (I.R., M.T.), Université de Nice Sophia Antipolis, 06107 Nice, France; Metabolic Diseases Branch (M.C., L.S.W.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Program in Membrane Biology (V.M.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Marshansky
authors.affiliation: Endocrine Unit (Z.Y., Q.H., C.A., H.J., M.B.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Department of Endodontics (C.A.), Gülhane Military Medical Academy, 06018 Ankara, Turkey; Faculty of Medicine (I.R., M.T.), Université de Nice Sophia Antipolis, 06107 Nice, France; Metabolic Diseases Branch (M.C., L.S.W.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Program in Membrane Biology (V.M.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114.
authors.forename: Harald
authors.initials: H
authors.lastname: Jüppner
authors.affiliation: Endocrine Unit (Z.Y., Q.H., C.A., H.J., M.B.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Department of Endodontics (C.A.), Gülhane Military Medical Academy, 06018 Ankara, Turkey; Faculty of Medicine (I.R., M.T.), Université de Nice Sophia Antipolis, 06107 Nice, France; Metabolic Diseases Branch (M.C., L.S.W.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Program in Membrane Biology (V.M.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114.
authors.forename: Murat
authors.initials: M
authors.lastname: Bastepe
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D015536:Down-Regulation / Q000235:genetics; D004351:Drug Resistance / Q000235:genetics*; D005260:Female; D000089703:Fibroblast Growth Factor-23; D044385:GTP-Binding Protein alpha Subunits / Q000235:genetics*; D007687:Kidney Tubules, Proximal / Q000378:metabolism* / Q000473:pathology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D010281:Parathyroid Hormone / Q000378:metabolism / Q000494:pharmacology*; D011556:Pseudopseudohypoparathyroidism / Q000235:genetics* / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D015854:Up-Regulation / Q000235:genetics; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D065668:Vitamin D3 24-Hydroxylase / Q000235:genetics* / Q000378:metabolism
chemical_list: C000717428:Fgf23 protein, mouse; D044385:GTP-Binding Protein alpha Subunits; D010281:Parathyroid Hormone; D012333:RNA, Messenger; D014807:Vitamin D; C097949:1,25-dihydroxyvitamin D; D000089703:Fibroblast Growth Factor-23; C585550:Cyp24a1 protein, mouse; D065668:Vitamin D3 24-Hydroxylase