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Gao F, Hayashi Y, Saravanaperumal SA, Gajdos GB, Syed SA, Bhagwate AV, Ye Z, Zhong J, Zhang Y, Choi EL, Kvasha SM, Kaur J, Paradise BD, Cheng L, Simone BW, Wright AM, Kellogg TA, Kendrick ML, McKenzie TJ, Sun Z, Yan H, Yu C, Bharucha AE, Linden DR, Lee JH, Ordog T. Hypoxia-Inducible Factor 1α Stabilization Restores Epigenetic Control of Nitric Oxide Synthase 1 Expression and Reverses Gastroparesis in Female Diabetic Mice. Gastroenterology 2023; 165:1458-1474. [PMID: 37597632 PMCID: PMC10840755 DOI: 10.1053/j.gastro.2023.08.009] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 07/18/2023] [Accepted: 08/09/2023] [Indexed: 08/21/2023]
Abstract
BACKGROUND & AIMS Although depletion of neuronal nitric oxide synthase (NOS1)-expressing neurons contributes to gastroparesis, stimulating nitrergic signaling is not an effective therapy. We investigated whether hypoxia-inducible factor 1α (HIF1A), which is activated by high O2 consumption in central neurons, is a Nos1 transcription factor in enteric neurons and whether stabilizing HIF1A reverses gastroparesis. METHODS Mice with streptozotocin-induced diabetes, human and mouse tissues, NOS1+ mouse neuroblastoma cells, and isolated nitrergic neurons were studied. Gastric emptying of solids and volumes were determined by breath test and single-photon emission computed tomography, respectively. Gene expression was analyzed by RNA-sequencing, microarrays, immunoblotting, and immunofluorescence. Epigenetic assays included chromatin immunoprecipitation sequencing (13 targets), chromosome conformation capture sequencing, and reporter assays. Mechanistic studies used Cre-mediated recombination, RNA interference, and clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9)-mediated epigenome editing. RESULTS HIF1A signaling from physiological intracellular hypoxia was active in mouse and human NOS1+ myenteric neurons but reduced in diabetes. Deleting Hif1a in Nos1-expressing neurons reduced NOS1 protein by 50% to 92% and delayed gastric emptying of solids in female but not male mice. Stabilizing HIF1A with roxadustat (FG-4592), which is approved for human use, restored NOS1 and reversed gastroparesis in female diabetic mice. In nitrergic neurons, HIF1A up-regulated Nos1 transcription by binding and activating proximal and distal cis-regulatory elements, including newly discovered super-enhancers, facilitating RNA polymerase loading and pause-release, and by recruiting cohesin to loop anchors to alter chromosome topology. CONCLUSIONS Pharmacologic HIF1A stabilization is a novel, translatable approach to restoring nitrergic signaling and treating diabetic gastroparesis. The newly recognized effects of HIF1A on chromosome topology may provide insights into physioxia- and ischemia-related organ function.
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Affiliation(s)
- Fei Gao
- Enteric NeuroScience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota; Department of Gastroenterology, First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
| | - Yujiro Hayashi
- Enteric NeuroScience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Siva Arumugam Saravanaperumal
- Enteric NeuroScience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Gabriella B Gajdos
- Enteric NeuroScience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Sabriya A Syed
- Enteric NeuroScience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota; Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, Minnesota
| | - Aditya V Bhagwate
- Division of Computational Biology, Department of Quantitative Health Sciences, Mayo Clinic, Rochester, Minnesota
| | - Zhenqing Ye
- Division of Computational Biology, Department of Quantitative Health Sciences, Mayo Clinic, Rochester, Minnesota
| | - Jian Zhong
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota
| | - Yuebo Zhang
- Enteric NeuroScience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Egan L Choi
- Enteric NeuroScience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Sergiy M Kvasha
- Enteric NeuroScience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Jagneet Kaur
- Enteric NeuroScience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Brooke D Paradise
- Enteric NeuroScience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota; Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, Minnesota
| | - Liang Cheng
- Enteric NeuroScience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota; Division of Computational Biology, Department of Quantitative Health Sciences, Mayo Clinic, Rochester, Minnesota
| | - Brandon W Simone
- Enteric NeuroScience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota; Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, Minnesota
| | - Alec M Wright
- Enteric NeuroScience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Todd A Kellogg
- Department of Surgery, Mayo Clinic, Rochester, Minnesota
| | | | | | - Zhifu Sun
- Division of Computational Biology, Department of Quantitative Health Sciences, Mayo Clinic, Rochester, Minnesota; Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota
| | - Huihuang Yan
- Division of Computational Biology, Department of Quantitative Health Sciences, Mayo Clinic, Rochester, Minnesota; Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota
| | - Chuanhe Yu
- Enteric NeuroScience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Adil E Bharucha
- Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - David R Linden
- Enteric NeuroScience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Jeong-Heon Lee
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota; Division of Experimental Pathology and Laboratory Medicine, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Tamas Ordog
- Enteric NeuroScience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota; Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota.
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2
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Oliveira JL, Thompson CH, Saravanaperumal SA, Koganti T, Jenkinson G, Hein MS, Kohorst MA, Hasadsri L, Nguyen PL, Matern D, Kipp BR, Klee EW, Wieben ED, Hoyer JD, Rangan A. εγ-Thalassemia, a New Hemoglobinopathy Category. Clin Chem 2023:7136664. [PMID: 37086467 DOI: 10.1093/clinchem/hvad038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 03/07/2023] [Indexed: 04/24/2023]
Abstract
BACKGROUND Large β-globin gene cluster deletions (hereditary persistence of fetal hemoglobin [Hb] or β-, δβ-, γδβ-, and ϵγδβ-thalassemia), are associated with widely disparate phenotypes, including variable degrees of microcytic anemia and Hb F levels. When present, increased Hb A2 is used as a surrogate marker for β-thalassemia. Notably, ϵγδβ-thalassemias lack the essential regulatory locus control region (LCR) and cause severe transient perinatal anemia but normal newborn screen (NBS) results and Hb A2 levels. Herein, we report a novel deletion of the ϵ, Aγ, Gγ, and ψβ loci with intact LCR, δ-, and β-regions in 2 women and newborn twins. METHODS Capillary electrophoresis (CE), high-performance liquid chromatography (HPLC), DNA sequencing, multiplex ligation-dependent probe amplification (MLPA), gap-polymerase chain reaction (gap-PCR), and long-read sequencing (LRS) were performed. RESULTS NBS showed an Hb A > Hb F pattern for both twins. At 20 months, Hb A2 was increased similarly to that in the mother and an unrelated woman. Unexplained microcytosis was absent and the twins lacked severe neonatal anemia. MLPA, LRS, and gap-PCR confirmed a 32 599 base pair deletion of ϵ (HBE1) through ψβ (HBBP1) loci. CONCLUSIONS This deletion represents a hemoglobinopathy category with a distinct phenotype that has not been previously described, an ϵγ-thalassemia. Both the NBS Hb A > F pattern and the subsequent increased Hb A2 without microcytosis are unusual. A similar deletion should be considered when this pattern is encountered and appropriate test methods selected for detection. Knowledge of the clinical impact of this new category will improve genetic counselling, with distinction from the severe transient anemia associated with ϵγδβ-thalassemia.
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Affiliation(s)
- Jennifer L Oliveira
- Division of Hematopathology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | | | | | - Tejaswi Koganti
- Department of Clinical Genomics, Quantitative Health Sciences - Computational Biology, Mayo Clinic, Rochester, MN, United States
| | - Garrett Jenkinson
- Department of Clinical Genomics, Quantitative Health Sciences - Computational Biology, Mayo Clinic, Rochester, MN, United States
| | - Molly S Hein
- Division of Hematopathology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Mira A Kohorst
- Department of Pediatric Hematology-Oncology, Mayo Clinic, Rochester, MN, United States
| | - Linda Hasadsri
- Division of Laboratory Genetics and Genomics, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Phuong L Nguyen
- Division of Hematopathology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Dietrich Matern
- Division of Laboratory Genetics and Genomics, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Benjamin R Kipp
- Division of Laboratory Genetics and Genomics, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Eric W Klee
- Department of Clinical Genomics, Quantitative Health Sciences - Computational Biology, Mayo Clinic, Rochester, MN, United States
| | - Eric D Wieben
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, United States
- Department of Clinical Genomics, Quantitative Health Sciences - Computational Biology, Mayo Clinic, Rochester, MN, United States
| | - James D Hoyer
- Division of Hematopathology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Aruna Rangan
- Division of Hematopathology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
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Saravanaperumal SA, Pallotti S, Pediconi D, Renieri C, La Terza A. Exon-1 skipping and intron-1 retaining by alternative splicing of the c-KIT gene encodes a novel splice variant in the skin of Merino sheep (Ovis aries). Mol Biol Rep 2021; 48:4987-4994. [PMID: 34148208 DOI: 10.1007/s11033-021-06486-8] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 06/08/2021] [Indexed: 12/01/2022]
Abstract
c-KIT, a type III receptor protein tyrosine kinase, plays an essential role in melanocyte development, migration, and survival. Mutations within the c-KIT gene are previously shown to cause the white coat color phenotypes in pigs, mice, goats, and humans. However, up so far, the splicing isoform(s), genomic architecture of c-KIT have not been characterized well in merino sheep. Reverse transcriptase (RT)-PCR analysis with molecular prediction identified two basic splice variants: Transcript Variant-1, 2 for 12 bp insertion coding sequences (CDS) corresponding to the four amino acids 'GNSK', respectively. Using 5' RACE, here we report for the first time a novel c-KIT 'Transcript Variant-3' from the skin of merino sheep by comparative genome analyses at exon(1)-intron(1)-exon(2) boundaries. In contrast, a single product of 795 bp was characterized by 3' RACE. We also demonstrated that the c-KIT gene expression at the transcript level is not mediated via an intron-9 splicing event. Overall, beyond what was observed in other mammals, our data provide novel insights into the molecular structure of the c-KIT gene in sheep.
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Affiliation(s)
- Siva Arumugam Saravanaperumal
- Department of Physiology and Biomedical Engineering, Mayo Clinic, 200 First Street SW Guggenheim 10-21C, Rochester, MN, 55905, USA.
| | - Stefano Pallotti
- School of Pharmacy, University of Camerino, Via Gentile III da Varano, 62032, Camerino, Italy.
| | - Dario Pediconi
- School of Pharmacy, University of Camerino, Via Gentile III da Varano, 62032, Camerino, Italy
| | - Carlo Renieri
- School of Pharmacy, University of Camerino, Via Gentile III da Varano, 62032, Camerino, Italy
| | - Antonietta La Terza
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III da Varano, 62032, Camerino, Italy.
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4
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Hayashi Y, Asuzu DT, Bardsley MR, Gajdos GB, Kvasha SM, Linden DR, Nagy RA, Saravanaperumal SA, Syed SA, Toyomasu Y, Yan H, Chini EN, Gibbons SJ, Kellogg TA, Khazaie K, Kuro-o M, Machado Espindola Netto J, Singh MP, Tidball JG, Wehling-Henricks M, Farrugia G, Ordog T. Wnt-induced, TRP53-mediated Cell Cycle Arrest of Precursors Underlies Interstitial Cell of Cajal Depletion During Aging. Cell Mol Gastroenterol Hepatol 2020; 11:117-145. [PMID: 32771388 PMCID: PMC7672319 DOI: 10.1016/j.jcmgh.2020.07.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 07/29/2020] [Accepted: 07/30/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND & AIMS Gastric dysfunction in the elderly may cause reduced food intake, frailty, and increased mortality. The pacemaker and neuromodulator cells interstitial cells of Cajal (ICC) decline with age in humans, and their loss contributes to gastric dysfunction in progeric klotho mice hypomorphic for the anti-aging Klotho protein. The mechanisms of ICC depletion remain unclear. Klotho attenuates Wnt (wingless-type MMTV integration site) signaling. Here, we examined whether unopposed Wnt signaling could underlie aging-associated ICC loss by up-regulating transformation related protein TRP53 in ICC stem cells (ICC-SC). METHODS Mice aged 1-107 weeks, klotho mice, APCΔ468 mice with overactive Wnt signaling, mouse ICC-SC, and human gastric smooth muscles were studied by RNA sequencing, reverse transcription-polymerase chain reaction, immunoblots, immunofluorescence, histochemistry, flow cytometry, and methyltetrazolium, ethynyl/bromodeoxyuridine incorporation, and ex-vivo gastric compliance assays. Cells were manipulated pharmacologically and by gene overexpression and RNA interference. RESULTS The klotho and aged mice showed similar ICC loss and impaired gastric compliance. ICC-SC decline preceded ICC depletion. Canonical Wnt signaling and TRP53 increased in gastric muscles of klotho and aged mice and middle-aged humans. Overstimulated canonical Wnt signaling increased DNA damage response and TRP53 and reduced ICC-SC self-renewal and gastric ICC. TRP53 induction persistently inhibited G1/S and G2/M cell cycle phase transitions without activating apoptosis, autophagy, cellular quiescence, or canonical markers/mediators of senescence. G1/S block reflected increased cyclin-dependent kinase inhibitor 1B and reduced cyclin D1 from reduced extracellular signal-regulated kinase activity. CONCLUSIONS Increased Wnt signaling causes age-related ICC loss by up-regulating TRP53, which induces persistent ICC-SC cell cycle arrest without up-regulating canonical senescence markers.
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Affiliation(s)
- Yujiro Hayashi
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota,Yujiro Hayashi, PhD, Mayo Clinic, Guggenheim 10, 200 First Street SW, Rochester, Minnesota 55906. fax: (507) 255-6318.
| | - David T. Asuzu
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Michael R. Bardsley
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Gabriella B. Gajdos
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Sergiy M. Kvasha
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - David R. Linden
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Rea A. Nagy
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Siva Arumugam Saravanaperumal
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Sabriya A. Syed
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Yoshitaka Toyomasu
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Huihuang Yan
- Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota
| | - Eduardo N. Chini
- Signal Transduction and Molecular Nutrition Laboratory, Kogod Aging Center and Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota
| | - Simon J. Gibbons
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | | | | | - Makoto Kuro-o
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas,Division of Anti-aging Medicine, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Jair Machado Espindola Netto
- Signal Transduction and Molecular Nutrition Laboratory, Kogod Aging Center and Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota
| | | | - James G. Tidball
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California
| | | | - Gianrico Farrugia
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Tamas Ordog
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota,Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota,Correspondence Address correspondence to: Tamas Ordog, MD, Mayo Clinic, Guggenheim 10, 200 First Street SW, Rochester, Minnesota 55906. fax: (507) 255-6318.
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5
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Saravanaperumal SA, Gibbons SJ, Malysz J, Sha L, Linden DR, Szurszewski JH, Farrugia G. Extracellular Cl - regulates electrical slow waves and setting of smooth muscle membrane potential by interstitial cells of Cajal in mouse jejunum. Exp Physiol 2017; 103:40-57. [PMID: 28971566 DOI: 10.1113/ep086367] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [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: 03/17/2017] [Accepted: 09/27/2017] [Indexed: 12/12/2022]
Abstract
NEW FINDINGS What is the central question of this study? The aim was to investigate the roles of extracellular chloride in electrical slow waves and resting membrane potential of mouse jejunal smooth muscle by replacing chloride with the impermeant anions gluconate and isethionate. What is the main finding and its importance? The main finding was that in smooth muscle cells, the resting Cl- conductance is low, whereas transmembrane Cl- movement in interstitial cells of Cajal (ICCs) is a major contributor to the shape of electrical slow waves. Furthermore, the data confirm that ICCs set the smooth muscle membrane potential and that altering Cl- homeostasis in ICCs can alter the smooth muscle membrane potential. Intracellular Cl- homeostasis is regulated by anion-permeable channels and transporters and contributes to excitability of many cell types, including smooth muscle and interstitial cells of Cajal (ICCs). Our aims were to investigate the effects on electrical activity in mouse jejunal muscle strips of replacing extracellular Cl- (Cl-o ) with the impermeant anions gluconate and isethionate. On reducing Cl-o , effects were observed on electrical slow waves, with small effects on smooth muscle membrane voltage (Em ). Restoration of Cl- hyperpolarized smooth muscle Em proportional to the change in Cl-o concentration. Replacement of 90% of Cl-o with gluconate reversibly abolished slow waves in five of nine preparations. Slow waves were maintained in isethionate. Gluconate and isethionate substitution had similar concentration-dependent effects on peak amplitude, frequency, width at half peak amplitude, rise time and decay time of residual slow waves. Gluconate reduced free ionized Ca2+ in Krebs solutions to 0.13 mm. In Krebs solutions containing normal Cl- and 0.13 mm free Ca2+ , slow wave frequency was lower, width at half peak amplitude was smaller, and decay time was faster. The transient hyperpolarization following restoration of Cl-o was not observed in W/Wv mice, which lack pacemaker ICCs in the small intestine. We conclude that in smooth muscle cells, the resting Cl- conductance is low, whereas transmembrane Cl- movement in ICCs plays a major role in generation or propagation of slow waves. Furthermore, these data support a role for ICCs in setting smooth muscle Em and that altering Cl- homeostasis in ICCs can alter smooth muscle Em .
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Affiliation(s)
| | - Simon J Gibbons
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - John Malysz
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - Lei Sha
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - David R Linden
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - Joseph H Szurszewski
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - Gianrico Farrugia
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
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6
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Hayashi Y, Toyomasu Y, Saravanaperumal SA, Bardsley MR, Smestad JA, Lorincz A, Eisenman ST, Cipriani G, Nelson Holte MH, Al Khazal FJ, Syed SA, Gajdos GB, Choi KM, Stoltz GJ, Miller KE, Kendrick ML, Rubin BP, Gibbons SJ, Bharucha AE, Linden DR, Maher LJ, Farrugia G, Ordog T. Hyperglycemia Increases Interstitial Cells of Cajal via MAPK1 and MAPK3 Signaling to ETV1 and KIT, Leading to Rapid Gastric Emptying. Gastroenterology 2017; 153:521-535.e20. [PMID: 28438610 PMCID: PMC5526732 DOI: 10.1053/j.gastro.2017.04.020] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [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: 07/04/2016] [Revised: 04/14/2017] [Accepted: 04/17/2017] [Indexed: 12/27/2022]
Abstract
BACKGROUND & AIMS Depletion of interstitial cells of Cajal (ICCs) is common in diabetic gastroparesis. However, in approximately 20% of patients with diabetes, gastric emptying (GE) is accelerated. GE also occurs faster in obese individuals, and is associated with increased blood levels of glucose in patients with type 2 diabetes. To understand the fate of ICCs in hyperinsulinemic, hyperglycemic states characterized by rapid GE, we studied mice with mutation of the leptin receptor (Leprdb/db), which in our colony had accelerated GE. We also investigated hyperglycemia-induced signaling in the ICC lineage and ICC dependence on glucose oxidative metabolism in mice with disruption of the succinate dehydrogenase complex, subunit C gene (Sdhc). METHODS Mice were given breath tests to analyze GE of solids. ICCs were studied by flow cytometry, intracellular electrophysiology, isometric contractility measurement, reverse-transcription polymerase chain reaction, immunoblot, immunohistochemistry, enzyme-linked immunosorbent assays, and metabolite assays; cells and tissues were manipulated pharmacologically and by RNA interference. Viable cell counts, proliferation, and apoptosis were determined by methyltetrazolium, Ki-67, proliferating cell nuclear antigen, bromodeoxyuridine, and caspase-Glo 3/7 assays. Sdhc was disrupted in 2 different strains of mice via cre recombinase. RESULTS In obese, hyperglycemic, hyperinsulinemic female Leprdb/db mice, GE was accelerated and gastric ICC and phasic cholinergic responses were increased. Female KitK641E/+ mice, which have genetically induced hyperplasia of ICCs, also had accelerated GE. In isolated cells of the ICC lineage and gastric organotypic cultures, hyperglycemia stimulated proliferation by mitogen-activated protein kinase 1 (MAPK1)- and MAPK3-dependent stabilization of ets variant 1-a master transcription factor for ICCs-and consequent up-regulation of v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT) receptor tyrosine kinase. Opposite changes occurred in mice with disruption of Sdhc. CONCLUSIONS Hyperglycemia increases ICCs via oxidative metabolism-dependent, MAPK1- and MAPK3-mediated stabilization of ets variant 1 and increased expression of KIT, causing rapid GE. Increases in ICCs might contribute to the acceleration in GE observed in some patients with diabetes.
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Affiliation(s)
- Yujiro Hayashi
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
| | - Yoshitaka Toyomasu
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
| | - Siva Arumugam Saravanaperumal
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
| | - Michael R. Bardsley
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
| | - John A. Smestad
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
| | - Andrea Lorincz
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
| | | | | | | | - Fatimah J. Al Khazal
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
| | - Sabriya A. Syed
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota,Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
| | - Gabriella B. Gajdos
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
| | - Kyoung Moo Choi
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota
| | - Gary J. Stoltz
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Katie E. Miller
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | | | - Brian P. Rubin
- Departments of Anatomic Pathology and Cancer Biology, Robert J. Tomsich Pathology and Laboratory Medicine Institute, Lerner Research Institute and Taussig Cancer Center, Cleveland Clinic, Cleveland, Ohio
| | - Simon J. Gibbons
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Adil E. Bharucha
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
| | - David R. Linden
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Louis James Maher
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
| | | | - Tamas Ordog
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota.
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Beyder A, Gibbons SJ, Mazzone A, Strege PR, Saravanaperumal SA, Sha L, Higgins S, Eisenman ST, Bernard CE, Geurts A, Kline CF, Mohler PJ, Farrugia G. Expression and function of the Scn5a-encoded voltage-gated sodium channel NaV 1.5 in the rat jejunum. Neurogastroenterol Motil 2016; 28:64-73. [PMID: 26459913 PMCID: PMC4688076 DOI: 10.1111/nmo.12697] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [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: 07/21/2015] [Accepted: 09/05/2015] [Indexed: 12/20/2022]
Abstract
BACKGROUND The SCN5A-encoded voltage-gated sodium channel NaV 1.5 is expressed in human jejunum and colon. Mutations in NaV 1.5 are associated with gastrointestinal motility disorders. The rat gastrointestinal tract expresses voltage-gated sodium channels, but their molecular identity and role in rat gastrointestinal electrophysiology are unknown. METHODS The presence and distribution of Scn5a-encoded NaV 1.5 was examined by PCR, Western blotting and immunohistochemistry in rat jejunum. Freshly dissociated smooth muscle cells were examined by whole cell electrophysiology. Zinc finger nuclease was used to target Scn5a in rats. Lentiviral-mediated transduction with shRNA was used to target Scn5a in rat jejunum smooth muscle organotypic cultures. Organotypic cultures were examined by sharp electrode electrophysiology and RT-PCR. KEY RESULTS We found NaV 1.5 in rat jejunum and colon smooth muscle by Western blot. Immunohistochemistry using two other antibodies of different portions of NaV 1.5 revealed the presence of the ion channel in rat jejunum. Whole cell voltage-clamp in dissociated smooth muscle cells from rat jejunum showed fast activating and inactivating voltage-dependent inward current that was eliminated by Na(+) replacement by NMDG(+) . Constitutive rat Scn5a knockout resulted in death in utero. NaV 1.5 shRNA delivered by lentivirus into rat jejunum smooth muscle organotypic culture resulted in 57% loss of Scn5a mRNA and several significant changes in slow waves, namely 40% decrease in peak amplitude, 30% decrease in half-width, and 7 mV hyperpolarization of the membrane potential at peak amplitude. CONCLUSIONS & INFERENCES Scn5a-encoded NaV 1.5 is expressed in rat gastrointestinal smooth muscle and it contributes to smooth muscle electrophysiology.
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Affiliation(s)
- A Beyder
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - S J Gibbons
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - A Mazzone
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - P R Strege
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - S A Saravanaperumal
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - L Sha
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - S Higgins
- College of Medicine, University of Nebraska Medical Center, Omaha, NE, USA
| | - S T Eisenman
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - C E Bernard
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - A Geurts
- Human and Molecular Genetics Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | - C F Kline
- The Dorothy M. Davis Heart and Lung Research Institute and Departments of Physiology & Cell Biology and Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - P J Mohler
- The Dorothy M. Davis Heart and Lung Research Institute and Departments of Physiology & Cell Biology and Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - G Farrugia
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
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Saravanaperumal SA, Pediconi D, Renieri C, La Terza A. Alternative splicing of the sheep MITF gene: novel transcripts detectable in skin. Gene 2014; 552:165-75. [PMID: 25239663 DOI: 10.1016/j.gene.2014.09.031] [Citation(s) in RCA: 10] [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] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Revised: 09/12/2014] [Accepted: 09/15/2014] [Indexed: 01/05/2023]
Abstract
Microphthalmia-associated transcription factor (MITF) is a basic helix-loop-helix leucine zipper (bHLH-LZ) transcription factor, which regulates the differentiation and development of melanocytes and pigment cell-specific transcription of the melanogenesis enzyme genes. Though multiple splice variants of MITF have been reported in humans, mice and other vertebrate species, in merino sheep (Ovis aries), MITF gene splicing has not yet been investigated until now. To investigate the sheep MITF isoforms, the full length mRNA/cDNAs from the skin of merino sheep were cloned, sequenced and characterized. Reverse transcriptase (RT)-PCR analysis and molecular prediction revealed two basic splice variants with (+) and without (-) an 18 bp insertion viz. CGTGTATTTTCCCCACAG, in the coding region (CDS) for the amino acids 'ACIFPT'. It was further confirmed by the complete nucleotide sequencing of splice junction covering intron-6 (2463 bp), wherein an 18bp intronic sequence is retained into the CDS of MITF (+) isoform. Further, full-length cDNA libraries were enriched by the method of 5' and 3' rapid amplification of cDNA ends (RACE-PCR). A total of seven sheep MITF splice variants, with distinct N-terminus sequences such as MITF-A, B, E, H, and M, the counterparts of human and mouse MITF, were identified by 5' RACE. The other two 5' RACE products were found to be novel splice variants of MITF and represented as 'MITF truncated form (Trn)-1, 2'. These alternative splice (AS) variants were illustrated using comparative genome analysis. By means of 3' RACE three different MITF 3' UTRs (625, 1083, 3167bp) were identified and characterized. We also demonstrated that the MITF gene expression determined at transcript level is mediated via an intron-6 splicing event. Here we summarize for the first time, the expression of seven MITF splice variants with three distinct 3' UTRs in the skin of merino sheep. Our data refine the structure of the MITF gene in sheep beyond what was previously known in humans, mice, dogs and other mammals.
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Affiliation(s)
- Siva Arumugam Saravanaperumal
- Animal and Molecular Ecology Lab, School of Biosciences and Veterinary Medicine, University of Camerino, via Gentile III da Varano, Camerino, Macerata 62032, Italy.
| | - Dario Pediconi
- Animal and Molecular Ecology Lab, School of Biosciences and Veterinary Medicine, University of Camerino, via Gentile III da Varano, Camerino, Macerata 62032, Italy.
| | - Carlo Renieri
- Animal and Molecular Ecology Lab, School of Biosciences and Veterinary Medicine, University of Camerino, via Gentile III da Varano, Camerino, Macerata 62032, Italy.
| | - Antonietta La Terza
- Animal and Molecular Ecology Lab, School of Biosciences and Veterinary Medicine, University of Camerino, via Gentile III da Varano, Camerino, Macerata 62032, Italy.
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Singh RD, Gibbons SJ, Saravanaperumal SA, Du P, Hennig GW, Eisenman ST, Mazzone A, Hayashi Y, Cao C, Stoltz GJ, Ordog T, Rock JR, Harfe BD, Szurszewski JH, Farrugia G. Ano1, a Ca2+-activated Cl- channel, coordinates contractility in mouse intestine by Ca2+ transient coordination between interstitial cells of Cajal. J Physiol 2014; 592:4051-68. [PMID: 25063822 DOI: 10.1113/jphysiol.2014.277152] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Interstitial cells of Cajal (ICC) are pacemaker cells that generate electrical activity to drive contractility in the gastrointestinal tract via ion channels. Ano1 (Tmem16a), a Ca(2+)-activated Cl(-) channel, is an ion channel expressed in ICC. Genetic deletion of Ano1 in mice resulted in loss of slow waves in smooth muscle of small intestine. In this study, we show that Ano1 is required to maintain coordinated Ca(2+) transients between myenteric ICC (ICC-MY) of small intestine. First, we found spontaneous Ca(2+) transients in ICC-MY in both Ano1 WT and knockout (KO) mice. However, Ca(2+) transients within the ICC-MY network in Ano1 KO mice were uncoordinated, while ICC-MY Ca(2+) transients in Ano1 WT mice were rhythmic and coordinated. To confirm the role of Ano1 in the loss of Ca(2+) transient coordination, we used pharmacological inhibitors of Ano1 activity and shRNA-mediated knock down of Ano1 expression in organotypic cultures of Ano1 WT small intestine. Coordinated Ca(2+) transients became uncoordinated using both these approaches, supporting the conclusion that Ano1 is required to maintain coordination/rhythmicity of Ca(2+) transients. We next determined the effect on smooth muscle contractility using spatiotemporal maps of contractile activity in Ano1 KO and WT tissues. Significantly decreased contractility that appeared to be non-rhythmic and uncoordinated was observed in Ano1 KO jejunum. In conclusion, Ano1 has a previously unidentified role in the regulation of coordinated gastrointestinal smooth muscle function through coordination of Ca(2+) transients in ICC-MY.
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Affiliation(s)
- Raman Deep Singh
- Department of Physiology and Biomedical Engineering Enteric NeuroScience Program, Mayo Clinic, Rochester, MN, USA
| | - Simon J Gibbons
- Department of Physiology and Biomedical Engineering Enteric NeuroScience Program, Mayo Clinic, Rochester, MN, USA
| | | | - Peng Du
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Grant W Hennig
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, USA
| | - Seth T Eisenman
- Department of Physiology and Biomedical Engineering Enteric NeuroScience Program, Mayo Clinic, Rochester, MN, USA
| | - Amelia Mazzone
- Department of Physiology and Biomedical Engineering Enteric NeuroScience Program, Mayo Clinic, Rochester, MN, USA
| | - Yujiro Hayashi
- Department of Physiology and Biomedical Engineering Enteric NeuroScience Program, Mayo Clinic, Rochester, MN, USA
| | - Chike Cao
- Department of Physiology and Biomedical Engineering Enteric NeuroScience Program, Mayo Clinic, Rochester, MN, USA
| | - Gary J Stoltz
- Department of Physiology and Biomedical Engineering Enteric NeuroScience Program, Mayo Clinic, Rochester, MN, USA
| | - Tamas Ordog
- Department of Physiology and Biomedical Engineering Enteric NeuroScience Program, Mayo Clinic, Rochester, MN, USA
| | - Jason R Rock
- Department of Anatomy, UCSF School of Medicine, San Francisco, CA, USA
| | - Brian D Harfe
- Department of Molecular Genetics and Microbiology Genetics Institute, University of Florida, College of Medicine, Gainesville, FL, USA
| | - Joseph H Szurszewski
- Department of Physiology and Biomedical Engineering Enteric NeuroScience Program, Mayo Clinic, Rochester, MN, USA
| | - Gianrico Farrugia
- Department of Physiology and Biomedical Engineering Enteric NeuroScience Program, Mayo Clinic, Rochester, MN, USA
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Saravanaperumal SA, Pediconi D, Renieri C, La Terza A. Skipping of exons by premature termination of transcription and alternative splicing within intron-5 of the sheep SCF gene: a novel splice variant. PLoS One 2012; 7:e38657. [PMID: 22719917 PMCID: PMC3376141 DOI: 10.1371/journal.pone.0038657] [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] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Accepted: 05/08/2012] [Indexed: 11/23/2022] Open
Abstract
Stem cell factor (SCF) is a growth factor, essential for haemopoiesis, mast cell development and melanogenesis. In the hematopoietic microenvironment (HM), SCF is produced either as a membrane-bound (-) or soluble (+) forms. Skin expression of SCF stimulates melanocyte migration, proliferation, differentiation, and survival. We report for the first time, a novel mRNA splice variant of SCF from the skin of white merino sheep via cloning and sequencing. Reverse transcriptase (RT)-PCR and molecular prediction revealed two different cDNA products of SCF. Full-length cDNA libraries were enriched by the method of rapid amplification of cDNA ends (RACE-PCR). Nucleotide sequencing and molecular prediction revealed that the primary 1519 base pair (bp) cDNA encodes a precursor protein of 274 amino acids (aa), commonly known as 'soluble' isoform. In contrast, the shorter (835 and/or 725 bp) cDNA was found to be a 'novel' mRNA splice variant. It contains an open reading frame (ORF) corresponding to a truncated protein of 181 aa (vs 245 aa) with an unique C-terminus lacking the primary proteolytic segment (28 aa) right after the D(175)G site which is necessary to produce 'soluble' form of SCF. This alternative splice (AS) variant was explained by the complete nucleotide sequencing of splice junction covering exon 5-intron (5)-exon 6 (948 bp) with a premature termination codon (PTC) whereby exons 6 to 9/10 are skipped (Cassette Exon, CE 6-9/10). We also demonstrated that the Northern blot analysis at transcript level is mediated via an intron-5 splicing event. Our data refine the structure of SCF gene; clarify the presence (+) and/or absence (-) of primary proteolytic-cleavage site specific SCF splice variants. This work provides a basis for understanding the functional role and regulation of SCF in hair follicle melanogenesis in sheep beyond what was known in mice, humans and other mammals.
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Affiliation(s)
| | - Dario Pediconi
- School of Environmental Sciences, University of Camerino, via Gentile III da Varano, Camerino (MC), Italy
| | - Carlo Renieri
- School of Environmental Sciences, University of Camerino, via Gentile III da Varano, Camerino (MC), Italy
| | - Antonietta La Terza
- School of Environmental Sciences, University of Camerino, via Gentile III da Varano, Camerino (MC), Italy
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