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Małachowska B, Janikiewicz J, Pietrowska K, Wyka K, Madzio J, Wypyszczak K, Tkaczyk M, Chrul S, Zwiech R, Hogendorf A, Małecki MT, Borowiec M, Krętowski A, Młynarski W, Dobrzyń A, Ciborowski M, Fendler W. Elevated level of lysophosphatidic acid among patients with HNF1B mutations and its role in RCAD syndrome: a multiomic study. Metabolomics 2022; 18:15. [PMID: 35179657 PMCID: PMC8857088 DOI: 10.1007/s11306-022-01873-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 02/01/2022] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Patients with hepatocyte nuclear factor-1 beta (HNF1B) mutations present a variable phenotype with two main symptoms: maturity onset diabetes of the young (MODY) and polycystic kidney disease (PKD). OBJECTIVES Identification of serum metabolites specific for HNF1Bmut and evaluation of their role in disease pathogenesis. METHODS We recruited patients with HNF1Bmut (N = 10), HNF1Amut (N = 10), PKD: non-dialyzed and dialyzed (N = 8 and N = 13); and healthy controls (N = 12). Serum fingerprinting was performed by LC-QTOF-MS. Selected metabolite was validated by ELISA (enzyme-linked immunosorbent assay) measurements and then biologically connected with HNF1B by in silico analysis. HepG2 were stimulated with lysophosphatidic acid (LPA) and HNF1B gene was knocked down (kd) by small interfering RNA. Transcriptomic analysis with microarrays and western blot measurements were performed. RESULTS Serum levels of six metabolites including: arachidonic acid, hydroxyeicosatetraenoic acid, linoleamide and three LPA (18:1, 18:2 and 20:4), had AUC (the area under the curve) > 0.9 (HNF1Bmut vs comparative groups). The increased level of LPA was confirmed by ELISA measurements. In HepG2HNF1Bkd cells LPA stimulation lead to downregulation of many pathways associated with cell cycle, lipid metabolism, and upregulation of steroid hormone metabolism and Wnt signaling. Also, increased intracellular protein level of autotaxin was detected in the cells. GSK-3alpha/beta protein level and its phosphorylated ratio were differentially affected by LPA stimulation in HNF1Bkd and control cells. CONCLUSIONS LPA is elevated in sera of patients with HNF1Bmut. LPA contributes to the pathogenesis of HNF1B-MODY by affecting Wnt/GSK-3 signaling.
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Affiliation(s)
- Beata Małachowska
- Department of Biostatistics and Translational Medicine, Medical University of Lodz, 15 Mazowiecka Street, 92-215, Lodz, Poland
| | - Justyna Janikiewicz
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology PAS, 3 Pasteur Street, 02-093, Warsaw, Poland
| | - Karolina Pietrowska
- Clinical Research Centre, Medical University of Bialystok, 24a Sklodowska-Curie Street, 15-276, Bialystok, Poland
| | - Krystyna Wyka
- Department of Pediatrics, Oncology and Hematology, Medical University of Lodz, 36/50 Sporna Street, 91-738, Lodz, Poland
| | - Joanna Madzio
- Department of Pediatrics, Oncology and Hematology, Medical University of Lodz, 36/50 Sporna Street, 91-738, Lodz, Poland
| | - Kamila Wypyszczak
- Department of Pediatrics, Oncology and Hematology, Medical University of Lodz, 36/50 Sporna Street, 91-738, Lodz, Poland
| | - Marcin Tkaczyk
- Department of Pediatrics, Immunology and Nephrology, Polish Mother's Memorial Hospital Research Institute, 281/289 Rzgowska Street, 93-338, Lodz, Poland
- Department of Pediatrics Nephrology and Immunology, Medical University of Lodz, 281/289 Rzgowska Street, 93-338, Lodz, Poland
| | - Sławomir Chrul
- Department of Pediatrics, Immunology and Nephrology, Polish Mother's Memorial Hospital Research Institute, 281/289 Rzgowska Street, 93-338, Lodz, Poland
| | - Rafał Zwiech
- Department of Kidney Transplantation/Dialysis Department, Barlicki Memorial Teaching Hospital No. 1, Medical University of Lodz, 22 Kopcinskiego Street, 90-153, Lodz, Poland
| | - Anna Hogendorf
- Department of Pediatrics, Diabetology, Endocrinology, and Nephrology, Medical University of Lodz, 36/50 Sporna Street, 91-738, Lodz, Poland
| | - Maciej T Małecki
- Department of Metabolic Diseases, Medical College, Jagiellonian University, 2 Jakubowskiego Street, 30-688, Cracov, Poland
| | - Maciej Borowiec
- Department of Clinical Genetics, Medical University of Lodz, 251 Pomorska Street, 92-213, Lodz, Poland
| | - Adam Krętowski
- Clinical Research Centre, Medical University of Bialystok, 24a Sklodowska-Curie Street, 15-276, Bialystok, Poland
- Department of Endocrinology, Diabetology, and Internal Medicine, Medical University of Bialystok, 24a Sklodowska-Curie Street, 15-276, Bialystok, Poland
| | - Wojciech Młynarski
- Department of Pediatrics, Oncology and Hematology, Medical University of Lodz, 36/50 Sporna Street, 91-738, Lodz, Poland
| | - Agnieszka Dobrzyń
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology PAS, 3 Pasteur Street, 02-093, Warsaw, Poland
| | - Michał Ciborowski
- Clinical Research Centre, Medical University of Bialystok, 24a Sklodowska-Curie Street, 15-276, Bialystok, Poland
| | - Wojciech Fendler
- Department of Biostatistics and Translational Medicine, Medical University of Lodz, 15 Mazowiecka Street, 92-215, Lodz, Poland.
- Department of Radiation Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA, 02215, USA.
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Mehta YR, Lewis SA, Leo KT, Chen L, Park E, Raghuram V, Chou CL, Yang CR, Kikuchi H, Khundmiri S, Poll BG, Knepper MA. "ADPKD-omics": determinants of cyclic AMP levels in renal epithelial cells. Kidney Int 2022; 101:47-62. [PMID: 34757121 PMCID: PMC10671900 DOI: 10.1016/j.kint.2021.10.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 09/30/2021] [Accepted: 10/12/2021] [Indexed: 12/30/2022]
Abstract
The regulation of cyclic adenosine monophosphate (cAMP) levels in kidney epithelial cells is important in at least 2 groups of disorders, namely water balance disorders and autosomal dominant polycystic kidney disease. Focusing on the latter, we review genes that code for proteins that are determinants of cAMP levels in cells. We identify which of these determinants are expressed in the 14 kidney tubule segments using recently published RNA-sequencing and protein mass spectrometry data ("autosomal dominant polycystic kidney disease-omics"). This includes G protein-coupled receptors, adenylyl cyclases, cyclic nucleotide phosphodiesterases, cAMP transporters, cAMP-binding proteins, regulator of G protein-signaling proteins, G protein-coupled receptor kinases, arrestins, calcium transporters, and calcium-binding proteins. In addition, compartmentalized cAMP signaling in the primary cilium is discussed, and a specialized database of the proteome of the primary cilium of cultured "IMCD3" cells is provided as an online resource (https://esbl.nhlbi.nih.gov/Databases/CiliumProteome/). Overall, this article provides a general resource in the form of a curated list of proteins likely to play roles in determination of cAMP levels in kidney epithelial cells and, therefore, likely to be determinants of progression of autosomal dominant polycystic kidney disease.
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Affiliation(s)
- Yash R Mehta
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Spencer A Lewis
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Kirby T Leo
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Lihe Chen
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Euijung Park
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Viswanathan Raghuram
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Chung-Lin Chou
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Chin-Rang Yang
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Hiroaki Kikuchi
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Syed Khundmiri
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Brian G Poll
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Mark A Knepper
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA.
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3
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Walia V, Cuenca A, Vetter M, Insinna C, Perera S, Lu Q, Ritt DA, Semler E, Specht S, Stauffer J, Morrison DK, Lorentzen E, Westlake CJ. Akt Regulates a Rab11-Effector Switch Required for Ciliogenesis. Dev Cell 2019; 50:229-246.e7. [PMID: 31204173 DOI: 10.1016/j.devcel.2019.05.022] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 02/08/2019] [Accepted: 05/09/2019] [Indexed: 11/29/2022]
Abstract
Serum starvation stimulates cilia growth in cultured cells, yet serum factors associated with ciliogenesis are unknown. Previously, we showed that starvation induces rapid Rab11-dependent vesicular trafficking of Rabin8, a Rab8 guanine-nucleotide exchange factor (GEF), to the mother centriole, leading to Rab8 activation and cilium growth. Here, we demonstrate that through the LPA receptor 1 (LPAR1), serum lysophosphatidic acid (LPA) inhibits Rab11a-Rabin8 interaction and ciliogenesis. LPA/LPAR1 regulates ciliogenesis initiation via downstream PI3K/Akt activation, independent of effects on cell cycle. Akt stabilizes Rab11a binding to its effector, WDR44, and a WDR44-pAkt-phosphomimetic mutant blocks ciliogenesis. WDR44 depletion promotes Rabin8 preciliary trafficking and ciliogenesis-initiating events at the mother centriole. Our work suggests disruption of Akt signaling causes a switch from Rab11-WDR44 to the ciliogenic Rab11-FIP3-Rabin8 complex. Finally, we demonstrate that Akt regulates downstream ciliogenesis processes associated with Rab8-dependent cilia growth. Together, this study uncovers a mechanism whereby serum mitogen signaling regulates Rabin8 preciliary trafficking and ciliogenesis initiation.
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Affiliation(s)
- Vijay Walia
- Center for Cancer Research, NCI Frederick, Laboratory of Cellular and Developmental Signaling, Frederick, MD 21702, USA
| | - Adrian Cuenca
- Center for Cancer Research, NCI Frederick, Laboratory of Cellular and Developmental Signaling, Frederick, MD 21702, USA
| | - Melanie Vetter
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, 8000 Aarhus C, Denmark
| | - Christine Insinna
- Center for Cancer Research, NCI Frederick, Laboratory of Cellular and Developmental Signaling, Frederick, MD 21702, USA
| | - Sumeth Perera
- Center for Cancer Research, NCI Frederick, Laboratory of Cellular and Developmental Signaling, Frederick, MD 21702, USA
| | - Quanlong Lu
- Center for Cancer Research, NCI Frederick, Laboratory of Cellular and Developmental Signaling, Frederick, MD 21702, USA
| | - Daniel A Ritt
- Center for Cancer Research, NCI Frederick, Laboratory of Cellular and Developmental Signaling, Frederick, MD 21702, USA
| | - Elizabeth Semler
- Center for Cancer Research, NCI Frederick, Laboratory of Cellular and Developmental Signaling, Frederick, MD 21702, USA
| | - Suzanne Specht
- Center for Cancer Research, NCI Frederick, Laboratory of Cellular and Developmental Signaling, Frederick, MD 21702, USA
| | - Jimmy Stauffer
- Center for Cancer Research, NCI Frederick, Laboratory of Cellular and Developmental Signaling, Frederick, MD 21702, USA
| | - Deborah K Morrison
- Center for Cancer Research, NCI Frederick, Laboratory of Cellular and Developmental Signaling, Frederick, MD 21702, USA
| | - Esben Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, 8000 Aarhus C, Denmark
| | - Christopher J Westlake
- Center for Cancer Research, NCI Frederick, Laboratory of Cellular and Developmental Signaling, Frederick, MD 21702, USA.
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Abstract
Lysophosphatidic acid (LPA) is a bioactive phospholipid that can exert diverse biological effects in various diseased states of the kidney by activating at least six cognate G protein-coupled receptors and its complex network of heterotrimeric G proteins. In many models of acute and chronic kidney injury, pathological elevations in LPA promotes abnormal changes in renal tubular epithelial cell architecture by activating apoptotic signaling, recruits immune cells to the site of injury, and stimulates profibrotic signaling by increasing gene transcription. In renal cancers, LPA can promote vascular cell proliferation and tumor cell invasion. In this review, a summary will be provided to describe the involvement of LPA, its synthetic enzymes, and its associated receptors in normal and diseased kidneys. Further elucidation of the LPA system may open new doors in developing a lipid-receptor therapeutic platform for kidney diseases.
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Affiliation(s)
- Frank Park
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Duane D Miller
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee
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Ayasolla KR, Rai P, Rahimipour S, Hussain M, Malhotra A, Singhal PC. Tubular cell phenotype in HIV-associated nephropathy: role of phospholipid lysophosphatidic acid. Exp Mol Pathol 2015; 99:109-15. [PMID: 26079546 DOI: 10.1016/j.yexmp.2015.06.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 06/12/2015] [Indexed: 11/19/2022]
Abstract
Collapsing glomerulopathy and microcysts are characteristic histological features of HIV-associated nephropathy (HIVAN). We have previously reported the role of epithelial mesenchymal transition (EMT) in the development of glomerular and tubular cell phenotypes in HIVAN. Since persistent tubular cell activation of NFκB has been reported in HIVAN, we now hypothesize that HIV may be contributing to tubular cell phenotype via lysophosphatidic acid (LPA) mediated downstream signaling. Interestingly, LPA and its receptors have also been implicated in the tubular interstitial cell fibrosis (TIF) and cyst formation in autosomal dominant polycystic kidney disease (PKD). Primary human proximal tubular cells (HRPTCs) were transduced with either empty vector (EV/HRPTCs), HIV (HIV/HRPTCs) or treated with LPA (LPA/HRPTC). Immunoelectrophoresis of HIV/HRPTCs and LPA/HRPTCs displayed enhanced expression of pro-fibrotic markers: a) fibronectin (2.25 fold), b) connective tissue growth factor (CTGF; 4.8 fold), c) α-smooth muscle actin (α-SMA; 12 fold), and d) collagen I (5.7 fold). HIV enhanced tubular cell phosphorylation of ILK-1, FAK, PI3K, Akt, ERKs and P38 MAPK. HIV increased tubular cell transcriptional binding activity of NF-κB; whereas, a LPA biosynthesis inhibitor (AACOCF3), a DAG kinase inhibitor, a LPA receptor blocker (Ki16425), a NF-κB inhibitor (PDTC) and NFκB-siRNA not only displayed downregulation of a NFκB activity but also showed attenuated expression of profibrotic/EMT genes in HIV milieu. These findings suggest that LPA could be contributing to HIV-induced tubular cell phenotype via NFκB activation in HIVAN.
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Affiliation(s)
- Kamesh R Ayasolla
- Department of Medicine, Hofstra North-Shore LIJ Medical School, Feinstein Institute for Medical Research, NY, United States
| | - Partab Rai
- Department of Medicine, Hofstra North-Shore LIJ Medical School, Feinstein Institute for Medical Research, NY, United States
| | - Shai Rahimipour
- Department of Chemistry, Bar-Ilan University, Ramat Gan, Israel
| | | | - Ashwani Malhotra
- Department of Medicine, Hofstra North-Shore LIJ Medical School, Feinstein Institute for Medical Research, NY, United States
| | - Pravin C Singhal
- Department of Medicine, Hofstra North-Shore LIJ Medical School, Feinstein Institute for Medical Research, NY, United States.
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6
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Okazoe H, Zhang X, Liu D, Shibuya S, Ueda N, Sugimoto M, Kakehi Y. Expression and role of GPR87 in urothelial carcinoma of the bladder. Int J Mol Sci 2013; 14:12367-79. [PMID: 23752273 PMCID: PMC3709790 DOI: 10.3390/ijms140612367] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 06/01/2013] [Accepted: 06/03/2013] [Indexed: 11/16/2022] Open
Abstract
The orphan GPR87 has recently been matched with its ligand LPA, which is a lipid mediator with multiple physiological functions, including cancer cell proliferation. This study aimed to clarify the role of GPR87 in urothelial carcinoma of the bladder. GPR87 expression was assessed in seven human bladder cancer cell lines. A replication-deficient recombinant adenoviral vector expressing shRNA targeting GPR87 (Ad-shGPR87), was constructed. Gene silencing was carried out using Ad-shGPR87. Immunohistochemical analysis was performed for transurethral resection of bladder tumor samples from 71 patients with non-muscle-invasive bladder cancer. We observed GPR87 expression in five of the seven cell lines, and silencing GPR87 gene expression significantly reduced cell viability. GPR87 expression was positive in 38 (54%) of 71 tumors. Ki-67 index was associated with positive GPR87 staining status (p < 0.0001). Patients with GPR87-positive tumors had shorter intravesical recurrence-free survival than those with GPR87-negative tumors (p = 0.010). Multivariate analysis revealed that GPR87 staining status was an independent prognostic parameter for intravesical recurrence (p = 0.041). Progression from non-muscle-invasive to muscle-invasive tumor was more frequently observed in patients with GPR87-positive tumors, although this trend did not reach statistical significance (p = 0.056). These results warrant further prospective studies to clarify the role of GPR87 expression in intravesical recurrence and progression in bladder cancer.
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Affiliation(s)
- Homare Okazoe
- Department of Urology, Kagawa University Faculty of Medicine, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793, Japan; E-Mails: (H.O.); (X.Z.); (N.U.); (M.S.)
| | - Xia Zhang
- Department of Urology, Kagawa University Faculty of Medicine, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793, Japan; E-Mails: (H.O.); (X.Z.); (N.U.); (M.S.)
| | - Dage Liu
- Department of General Thoracic Surgery, Kagawa University Faculty of Medicine, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793, Japan; E-Mail:
| | - Shinsuke Shibuya
- Department of Diagnostic Pathology, Kagawa University Faculty of Medicine, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793, Japan; E-Mail:
| | - Nobufumi Ueda
- Department of Urology, Kagawa University Faculty of Medicine, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793, Japan; E-Mails: (H.O.); (X.Z.); (N.U.); (M.S.)
| | - Mikio Sugimoto
- Department of Urology, Kagawa University Faculty of Medicine, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793, Japan; E-Mails: (H.O.); (X.Z.); (N.U.); (M.S.)
| | - Yoshiyuki Kakehi
- Department of Urology, Kagawa University Faculty of Medicine, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793, Japan; E-Mails: (H.O.); (X.Z.); (N.U.); (M.S.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +81-87-891-2202; Fax: +81-87-891-2203
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Kmit A, van Kruchten R, Ousingsawat J, Mattheij NJA, Senden-Gijsbers B, Heemskerk JWM, Schreiber R, Bevers EM, Kunzelmann K. Calcium-activated and apoptotic phospholipid scrambling induced by Ano6 can occur independently of Ano6 ion currents. Cell Death Dis 2013; 4:e611. [PMID: 23618909 PMCID: PMC3668637 DOI: 10.1038/cddis.2013.135] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 02/16/2013] [Accepted: 03/11/2013] [Indexed: 11/17/2022]
Abstract
Immune cells and platelets maintain plasma membrane phospholipid asymmetry. Upon activation, this asymmetry is disrupted by phospholipid scrambling (PS), which is a major step during activation of immune cells, hemostasis and apoptosis. Anoctamin 6 (Ano6; TMEM16F) causes chloride (Cl(-)) and cation currents and is required for Ca(2+)-dependent PS. It is defective in blood cells from patients with Scott syndrome, a rare bleeding disorder. We examined if Cl(-) currents and PS are related, whether both processes are Ca(2+) dependent, and whether Ca(2+)-independent scrambling during intrinsic and extrinsic apoptosis is controlled by Ano6. Ca(2+) increase by ionomycin activated Ano6 Cl(-) currents and PS in normal lymphocytes, but not in B-lymphocytes from two different patients with Scott syndrome. Fas ligand (FasL) did not increase intracellular Ca(2+), but activated Cl(-) currents in normal but not in Scott lymphocytes. Whole-cell currents were inhibited by Cl(-) channel blockers and by siRNA knockdown of Ano6. In contrast, intrinsic mitochondrial apoptosis by ABT-737 did not induce Cl(-) currents in lymphocytes. PS was not inhibited by blockers of Ano6 or removal of Cl(-) ions. Remarkably, Ca(2+)-independent scrambling due to extrinsic (FasL) or intrinsic (ABT-737) apoptosis was unchanged in Scott cells. We conclude that: (i) Ano6 Cl(-) currents are activated by increase in cytosolic Ca(2+), or Ca(2+) independent by stimulation of Fas receptors; (ii) Ca(2+)-dependent PS induced by Ano6 does not require Cl(-) currents; (iii) Ca(2+)-independent PS does not require Ano6; (iv) Ano6 is necessary for Ca(2+)-dependent PS, but not by increasing intracellular Ca(2+).
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Affiliation(s)
- A Kmit
- Institut für Physiologie, Universität Regensburg, Regensburg, Germany
| | - R van Kruchten
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - J Ousingsawat
- Institut für Physiologie, Universität Regensburg, Regensburg, Germany
| | - N J A Mattheij
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - B Senden-Gijsbers
- Department of Internal Medicine, Division of Haematology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - J W M Heemskerk
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - R Schreiber
- Institut für Physiologie, Universität Regensburg, Regensburg, Germany
| | - E M Bevers
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - K Kunzelmann
- Institut für Physiologie, Universität Regensburg, Regensburg, Germany
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