1
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Wilkerson AD, Parthasarathy PB, Stabellini N, Mitchell C, Pavicic PG, Fu P, Rupani A, Husic H, Rayman PA, Swaidani S, Abraham J, Budd GT, Moore H, Al-Hilli Z, Ko JS, Baar J, Chan TA, Alban T, Diaz-Montero CM, Montero AJ. Phase II Clinical Trial of Pembrolizumab and Chemotherapy Reveals Distinct Transcriptomic Profiles by Radiologic Response in Metastatic Triple-Negative Breast Cancer. Clin Cancer Res 2024; 30:82-93. [PMID: 37882661 PMCID: PMC10767305 DOI: 10.1158/1078-0432.ccr-23-1349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 08/28/2023] [Accepted: 10/24/2023] [Indexed: 10/27/2023]
Abstract
PURPOSE A single arm, phase II trial of carboplatin, nab-paclitaxel, and pembrolizumab (CNP) in metastatic triple-negative breast cancer (mTNBC) was designed to evaluate overall response rate (ORR), progression-free survival (PFS), duration of response (DOR), safety/tolerability, overall survival (OS), and identify pathologic and transcriptomic correlates of response to therapy. PATIENTS AND METHODS Patients with ≤2 prior therapies for metastatic disease were treated with CNP regardless of tumor programmed cell death-ligand 1 status. Core tissue biopsies were obtained prior to treatment initiation. ORR was assessed using a binomial distribution. Survival was analyzed via the Kaplan-Meier method. Bulk RNA sequencing was employed for correlative studies. RESULTS Thirty patients were enrolled. The ORR was 48.0%: 2 (7%) complete responses (CR), 11 (41%) partial responses (PR), and 8 (30%) stable disease (SD). The median DOR for patients with CR or PR was 6.4 months [95% confidence interval (CI), 4-8.5 months]. For patients with CR, DOR was >24 months. Overall median PFS and OS were 5.8 (95% CI, 4.7-8.5 months) and 13.4 months (8.9-17.3 months), respectively. We identified unique transcriptomic landscapes associated with each RECIST category of radiographic treatment response. In CR and durable PR, IGHG1 expression was enriched. IGHG1high tumors were associated with improved OS (P = 0.045) and were concurrently enriched with B cells and follicular helper T cells, indicating IGHG1 as a promising marker for lymphocytic infiltration and robust response to chemo-immunotherapy. CONCLUSIONS Pretreatment tissue sampling in mTNBC treated with CNP reveals transcriptomic signatures that may predict radiographic responses to chemo-immunotherapy.
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Affiliation(s)
- Avia D. Wilkerson
- Cleveland Clinic Lerner Research Institute, Center for Immunotherapy & Precision Immuno-Oncology, Cleveland, Ohio
- Cleveland Clinic Digestive Disease & Surgery Institute, Department of General Surgery, Cleveland, Ohio
| | | | - Nickolas Stabellini
- Graduate Education Office, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Carley Mitchell
- University Hospitals Cleveland Medical Center, Department of Internal Medicine, Cleveland, Ohio
| | - Paul G. Pavicic
- Cleveland Clinic Lerner Research Institute, Center for Immunotherapy & Precision Immuno-Oncology, Cleveland, Ohio
| | - Pingfu Fu
- Case Western Reserve University, Department of Population and Quantitative Health Sciences, Cleveland, Ohio
| | - Amit Rupani
- Cleveland Clinic Lerner Research Institute, Center for Immunotherapy & Precision Immuno-Oncology, Cleveland, Ohio
| | - Hana Husic
- Cleveland Clinic Lerner Research Institute, Center for Immunotherapy & Precision Immuno-Oncology, Cleveland, Ohio
| | - Patricia A. Rayman
- Cleveland Clinic Lerner Research Institute, Center for Immunotherapy & Precision Immuno-Oncology, Cleveland, Ohio
| | - Shadi Swaidani
- Cleveland Clinic Lerner Research Institute, Center for Immunotherapy & Precision Immuno-Oncology, Cleveland, Ohio
| | - Jame Abraham
- Cleveland Clinic Department of Hematology and Medical Oncology, Taussig Cancer Center, Cleveland, Ohio
| | - G. Thomas Budd
- Cleveland Clinic Department of Hematology and Medical Oncology, Taussig Cancer Center, Cleveland, Ohio
| | - Halle Moore
- Cleveland Clinic Department of Hematology and Medical Oncology, Taussig Cancer Center, Cleveland, Ohio
| | - Zahraa Al-Hilli
- Cleveland Clinic Digestive Disease & Surgery Institute, Department of General Surgery, Cleveland, Ohio
| | - Jennifer S. Ko
- Cleveland Clinic Pathology & Laboratory Medicine, Department of Anatomic Pathology, Cleveland, Ohio
| | - Joseph Baar
- University Hospitals/Seidman Cancer Center Case Western Reserve University, Cleveland, Ohio
| | - Timothy A. Chan
- Cleveland Clinic Lerner Research Institute, Center for Immunotherapy & Precision Immuno-Oncology, Cleveland, Ohio
| | - Tyler Alban
- Cleveland Clinic Lerner Research Institute, Center for Immunotherapy & Precision Immuno-Oncology, Cleveland, Ohio
| | - C. Marcela Diaz-Montero
- Cleveland Clinic Lerner Research Institute, Center for Immunotherapy & Precision Immuno-Oncology, Cleveland, Ohio
| | - Alberto J. Montero
- University Hospitals/Seidman Cancer Center Case Western Reserve University, Cleveland, Ohio
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2
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Yuan M, Zeng C, Lu H, Yue Y, Sun T, Zhou X, Li G, Ai N, Ge W. Genetic and Epigenetic Evidence for Nonestrogenic Disruption of Otolith Development by Bisphenol A in Zebrafish. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:16190-16205. [PMID: 37752410 DOI: 10.1021/acs.est.3c04336] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/28/2023]
Abstract
Bisphenol A (BPA) is a well-known endocrine-disrupting chemical (EDC) that has estrogenic activities. In addition to disrupting reproductive development and function via estrogenic signaling pathways, BPA can also interfere with nonreproductive functions through nonestrogenic pathways; however, the mechanisms underlying such nonestrogenic activities are not well understood. In this study, we demonstrated that BPA could disrupt otolith formation during the early development of zebrafish with long-lasting ethological effects. Using multiple mutants of estrogen receptors, we provided strong genetic evidence that the BPA-induced otolith malformation was independent of estrogen signaling. Transcriptome analysis revealed that two genes related to otolith development, otopetrin 1 (otop1) and starmaker (stm), decreased their expression significantly after BPA exposure. Knockout of both otop1 and stm genes could phenocopy the BPA-induced otolith malformation, while microinjection of their mRNAs could rescue the BPA-induced abnormalities of otolith formation. Further experiments showed that BPA inhibited the expression of otop1 and stm by activating the MEK/ERK-EZH2-H3K27me3 signaling pathway. Taken together, our study provided comprehensive genetic and molecular evidence that BPA induced the otolith malformation through nonestrogenic pathway during zebrafish early development and its activities involved epigenetic control of key genes (e.g., otop1 and stm) participating in otolith formation.
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Affiliation(s)
- Mingzhe Yuan
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Macau, Taipa 999078, Macau, China
- Centre of Reproduction, Development and Aging (CRDA), Faculty of Health Sciences, University of Macau, Taipa 999078, Macau, China
| | - Chu Zeng
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Macau, Taipa 999078, Macau, China
- Centre of Reproduction, Development and Aging (CRDA), Faculty of Health Sciences, University of Macau, Taipa 999078, Macau, China
| | - Huijie Lu
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Macau, Taipa 999078, Macau, China
- Centre of Reproduction, Development and Aging (CRDA), Faculty of Health Sciences, University of Macau, Taipa 999078, Macau, China
| | - Yiming Yue
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Macau, Taipa 999078, Macau, China
- Centre of Reproduction, Development and Aging (CRDA), Faculty of Health Sciences, University of Macau, Taipa 999078, Macau, China
| | - Ting Sun
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Macau, Taipa 999078, Macau, China
| | - Xianqing Zhou
- Department of Toxicology and Hygienic Chemistry, School of Public Health, Capital Medical University, Beijing 100069, China
| | - Gang Li
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Macau, Taipa 999078, Macau, China
| | - Nana Ai
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Macau, Taipa 999078, Macau, China
- Centre of Reproduction, Development and Aging (CRDA), Faculty of Health Sciences, University of Macau, Taipa 999078, Macau, China
| | - Wei Ge
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Macau, Taipa 999078, Macau, China
- Centre of Reproduction, Development and Aging (CRDA), Faculty of Health Sciences, University of Macau, Taipa 999078, Macau, China
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3
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Tu YH, Liu N, Xiao C, Gavrilova O, Reitman ML. Loss of Otopetrin 1 affects thermoregulation during fasting in mice. PLoS One 2023; 18:e0292610. [PMID: 37812612 PMCID: PMC10561838 DOI: 10.1371/journal.pone.0292610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 09/09/2023] [Indexed: 10/11/2023] Open
Abstract
OBJECTIVE Otopetrin 1 (OTOP1) is a proton channel that is highly expressed in brown adipose tissue. We examined the physiology of Otop1-/- mice, which lack functional OTOP1. METHODS Mice were studied by indirect calorimetry and telemetric ambulatory body temperature monitoring. Mitochondrial function was measured as oxygen consumption and extracellular acidification. RESULTS Otop1-/- mice had similar body temperatures as control mice at baseline and in response to cold and hot ambient temperatures. However, in response to fasting the Otop1-/- mice exhibited an exaggerated hypothermia and hypometabolism. Similarly, in ex vivo tests of Otop1-/- brown adipose tissue mitochondrial function, there was no change in baseline oxygen consumption, but the oxygen consumption was reduced after maximal uncoupling with FCCP and increased upon stimulation with the β3-adrenergic agonist CL316243. Mast cells also express Otop1, and Otop1-/- mice had intact, possibly greater hypothermia in response to mast cell activation by the adenosine A3 receptor agonist MRS5698. No increase in insulin resistance was observed in the Otop1-/- mice. CONCLUSIONS Loss of OTOP1 does not change basal function of brown adipose tissue but affects stimulated responses.
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Affiliation(s)
- Yu-Hsiang Tu
- Diabetes, Endocrinology and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Naili Liu
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Cuiying Xiao
- Diabetes, Endocrinology and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Oksana Gavrilova
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Marc L. Reitman
- Diabetes, Endocrinology and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States of America
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4
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Li S, Al-Sheikh U, Chen Y, Kang L. Nematode homologs of the sour taste receptor Otopetrin1 are evolutionarily conserved acid-sensitive proton channels. Front Cell Dev Biol 2023; 11:1133890. [PMID: 36776560 PMCID: PMC9909269 DOI: 10.3389/fcell.2023.1133890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 01/16/2023] [Indexed: 01/27/2023] Open
Abstract
Numerous taste receptors and related molecules have been identified in vertebrates and invertebrates. Otopetrin1 has recently been identified as mammalian sour taste receptor which is essential for acid sensation. However, whether other Otopetrin proteins are involved in PH-sensing remains unknown. In C. elegans, there are eight otopetrin homologous genes but their expression patterns and functions have not been reported so far. Through heterologous expression in HEK293T cells, we found that ceOTOP1a can be activated by acid in NMDG+ solution without conventional cations, which generated inward currents and can be blocked by zinc ions. Moreover, we found that Otopetrin channels are widely expressed in numerous tissues, especially in sensory neurons in the nematode. These results suggest that the biophysical characteristics of the Otopetrin channels in nematodes are generally conserved. However, a series of single gene mutations of otopetrins, which were constructed by CRISPR-Cas9 method, did not affect either calcium responses in ASH polymodal sensory neurons to acid stimulation or acid avoidance behaviors, suggesting that Otopetrin channels might have diverse functions among species. This study reveals that nematode Otopetrins are evolutionarily conserved acid-sensitive proton channels, and provides a framework for further revealing the function and mechanisms of Otopetrin channels in both invertebrates and vertebrates.
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Affiliation(s)
- Shitian Li
- Department of Neurobiology and Department of Neurosurgery of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China,Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou, China,NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Umar Al-Sheikh
- Department of Neurobiology and Department of Neurosurgery of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China,Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou, China,NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yili Chen
- Department of Neurobiology and Department of Neurosurgery of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China,*Correspondence: Yili Chen, ; Lijun Kang,
| | - Lijun Kang
- Department of Neurobiology and Department of Neurosurgery of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China,Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou, China,NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China,*Correspondence: Yili Chen, ; Lijun Kang,
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5
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The roles of two extracellular loops in proton sensing and permeation in human Otop1 proton channel. Commun Biol 2022; 5:1110. [PMID: 36266567 PMCID: PMC9585144 DOI: 10.1038/s42003-022-04085-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 10/07/2022] [Indexed: 11/08/2022] Open
Abstract
Otopetrin (Otop) proteins were recently found to function as proton channels, with Otop1 revealed to be the sour taste receptor in mammals. Otop proteins contain twelve transmembrane segments (S1-S12) which are divided into structurally similar N and C domains. The mechanisms by which Otop channels sense extracellular protons to initiate gating and conduct protons once the channels are activated remains largely elusive. Here we show that two extracellular loops are playing key roles in human Otop1 channel function. We find that residue H229 in the S5-S6 loop is critical for proton sensing of Otop1. Further, our data reveal that the S11-12 loop is structurally and functionally essential for the Otop1 channel and that residue D570 in this loop regulates proton permeation into the pore formed by the C domain. This study sheds light on the molecular mechanism behind the structure and function of this newly identified ion channel family. Electrophysiology experiments, mutagenesis, and structural modelling provide insights into the structure and function of the sour taste receptor Otopetrin 1.
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6
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Song P, Zhao X, Xu Y, Zhao Z, Liu Y, Gao Q. Morphological Effect of Vitamin D Deficiency on Globular Substances in Mice. Otol Neurotol 2021; 42:e1313-e1317. [PMID: 34121084 DOI: 10.1097/mao.0000000000003229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
OBJECTIVE Many authors, including us, elucidated that vitamin D deficiency was a risk factor for benign paroxysmal position vertigo. We speculated vitamin D deficiency was likely to intervene otoconia formation by globular substance (GS). METHODS Kunming mice were randomly divided into three groups: vitamin D sufficient group (12-wk standard control diet), vitamin D deficiency group (16-wk vitamin D deficiency diet), and vitamin D supplement group (16-wk vitamin D deficiency diet and followed 8-wk standard control diet). At 12, 16, and 24 weeks, blood was collected for measuring vitamin D and macula utriculi were obtained for research under scanning electron microscope (SEM). We randomly selected 10 SEM photographs of macula utriculi in each mouse, counted cilium and GS, and measured diameters of counted GS. The ratio of the number of GS to cilium in each SEM photograph was defined as density of GS. RESULTS The diameter and density of GS were larger and higher in vitamin D deficiency group than sufficient group (p < 0.05; p < 0.05). There was no significant difference in density and diameters of GS between vitamin D deficiency and supplement group. The rough and grainy surface became smoother and smoother along with vitamin D deficiency, and reappeared after vitamin D supplement for 8 weeks. CONCLUSION GS secreted as a precursor of mature otoconia is affected by vitamin D deficiency and vitamin D supplementation can mitigate the effects in mice. The density of GS, a quantitative method we designed, can quantify GS well.
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Affiliation(s)
- Penglong Song
- Department of Otolaryngology/Head and Neck Surgery, The First Affiliated Hospital, Harbin Medical University
| | - Xianshu Zhao
- Health Center of Screening and Prevention of Diseases, The First Affiliated Hospital, Harbin Medical University, Harbin, China
| | - Yanjun Xu
- Department of Otolaryngology/Head and Neck Surgery, The First Affiliated Hospital, Harbin Medical University
| | - Zhigang Zhao
- Department of Otolaryngology/Head and Neck Surgery, The First Affiliated Hospital, Harbin Medical University
| | - Yang Liu
- Department of Otolaryngology/Head and Neck Surgery, The First Affiliated Hospital, Harbin Medical University
| | - Qian Gao
- Department of Otolaryngology/Head and Neck Surgery, The First Affiliated Hospital, Harbin Medical University
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7
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Mackowetzky K, Yoon KH, Mackowetzky EJ, Waskiewicz AJ. Development and evolution of the vestibular apparatuses of the inner ear. J Anat 2021; 239:801-828. [PMID: 34047378 PMCID: PMC8450482 DOI: 10.1111/joa.13459] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/07/2021] [Accepted: 05/06/2021] [Indexed: 12/16/2022] Open
Abstract
The vertebrate inner ear is a labyrinthine sensory organ responsible for perceiving sound and body motion. While a great deal of research has been invested in understanding the auditory system, a growing body of work has begun to delineate the complex developmental program behind the apparatuses of the inner ear involved with vestibular function. These animal studies have helped identify genes involved in inner ear development and model syndromes known to include vestibular dysfunction, paving the way for generating treatments for people suffering from these disorders. This review will provide an overview of known inner ear anatomy and function and summarize the exciting discoveries behind inner ear development and the evolution of its vestibular apparatuses.
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Affiliation(s)
- Kacey Mackowetzky
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
| | - Kevin H. Yoon
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
| | | | - Andrew J. Waskiewicz
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
- Women & Children’s Health Research InstituteUniversity of AlbertaEdmontonAlbertaCanada
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8
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Zhang J, Lee H, Macpherson LJ. Mechanisms for the Sour Taste. Handb Exp Pharmacol 2021; 275:229-245. [PMID: 34117536 DOI: 10.1007/164_2021_476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Sour, the taste of acids, provides important sensory information to prevent the ingestion of unripe, spoiled, or fermented foods. In mammals, acids elicit disgust and pain by simultaneously activating taste and somatosensory neurons innervating the oral cavity. Early researchers detected electrical activity in taste nerves upon presenting acids to the tongue, establishing this as the bona fide sour taste. Recent studies have made significant contributions to our understanding of the mechanisms underlying acid sensing in the taste receptor cells at the periphery and the neural circuitry that convey this information to the brain. In this chapter, we discuss the characterization of sour taste receptor cells, the twists and turns eventually leading to the identification of Otopetrin1 (OTOP1) as the sour taste receptor, the pathway of sour taste signaling from the tongue to the brainstem, and other roles sour taste receptor cells play in the taste bud.
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Affiliation(s)
- Jin Zhang
- Mortimer B. Zukerman Mind Brain and Behavior Institute, Columbia University, New York, NY, USA.
| | - Hojoon Lee
- Department of Neurobiology, Northwestern University, Evanston, IL, USA.
| | - Lindsey J Macpherson
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA.
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9
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Zimmer AM, Goss GG, Glover CN. Reductionist approaches to the study of ionoregulation in fishes. Comp Biochem Physiol B Biochem Mol Biol 2021; 255:110597. [PMID: 33781928 DOI: 10.1016/j.cbpb.2021.110597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/15/2021] [Accepted: 03/22/2021] [Indexed: 10/21/2022]
Abstract
The mechanisms underlying ionoregulation in fishes have been studied for nearly a century, and reductionist methods have been applied at all levels of biological organization in this field of research. The complex nature of ionoregulatory systems in fishes makes them ideally suited to reductionist methods and our collective understanding has been dramatically shaped by their use. This review provides an overview of the broad suite of techniques used to elucidate ionoregulatory mechanisms in fishes, from the whole-animal level down to the gene, discussing some of the advantages and disadvantages of these methods. We provide a roadmap for understanding and appreciating the work that has formed the current models of organismal, endocrine, cellular, molecular, and genetic regulation of ion balance in fishes and highlight the contribution that reductionist techniques have made to some of the fundamental leaps forward in the field throughout its history.
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Affiliation(s)
- Alex M Zimmer
- Department of Biological Sciences, CW 405, Biological Sciences Bldg., University of Alberta, Edmonton, AB T6G 2E9, Canada.
| | - Greg G Goss
- Department of Biological Sciences, CW 405, Biological Sciences Bldg., University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Chris N Glover
- Department of Biological Sciences, CW 405, Biological Sciences Bldg., University of Alberta, Edmonton, AB T6G 2E9, Canada; Faculty of Science and Technology and Athabasca River Basin Research Institute, Athabasca University, Athabasca, AB T9S 3A3, Canada
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10
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Abstract
Sour taste, which is evoked by low pH, is one of the original four fundamental taste qualities, recognized as a distinct taste sensation for centuries, and universally aversive across diverse species. It is generally assumed to have evolved for detection of acids in unripe fruit and spoiled food. But despite decades of study, only recently have the receptor, the neurotransmitter, and the circuits for sour taste been identified. In this review, we describe studies leading up to the identification of the sour receptor as OTOP1, an ion channel that is selectively permeable to protons. We also describe advances in our understanding of how information is transmitted from the taste receptor cells to gustatory neurons, leading to behavioral aversion to acids.
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Affiliation(s)
- Emily R Liman
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, 3641 Watt Way, Los Angeles, CA 90089, USA
| | - Sue C Kinnamon
- Department of Otolaryngology and Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, 12700 E 19(th) Avenue, Aurora, CO 80045, USA
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11
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Khor JM, Ettensohn CA. Transcription Factors of the Alx Family: Evolutionarily Conserved Regulators of Deuterostome Skeletogenesis. Front Genet 2020; 11:569314. [PMID: 33329706 PMCID: PMC7719703 DOI: 10.3389/fgene.2020.569314] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 10/19/2020] [Indexed: 12/13/2022] Open
Abstract
Members of the alx gene family encode transcription factors that contain a highly conserved Paired-class, DNA-binding homeodomain, and a C-terminal OAR/Aristaless domain. Phylogenetic and comparative genomic studies have revealed complex patterns of alx gene duplications during deuterostome evolution. Remarkably, alx genes have been implicated in skeletogenesis in both echinoderms and vertebrates. In this review, we provide an overview of current knowledge concerning alx genes in deuterostomes. We highlight their evolutionarily conserved role in skeletogenesis and draw parallels and distinctions between the skeletogenic gene regulatory circuitries of diverse groups within the superphylum.
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Affiliation(s)
- Jian Ming Khor
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States
| | - Charles A Ettensohn
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States
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12
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Wang Y, Zhang C, Wang N, Li Z, Heller R, Liu R, Zhao Y, Han J, Pan X, Zheng Z, Dai X, Chen C, Dou M, Peng S, Chen X, Liu J, Li M, Wang K, Liu C, Lin Z, Chen L, Hao F, Zhu W, Song C, Zhao C, Zheng C, Wang J, Hu S, Li C, Yang H, Jiang L, Li G, Liu M, Sonstegard TS, Zhang G, Jiang Y, Wang W, Qiu Q. Genetic basis of ruminant headgear and rapid antler regeneration. Science 2020; 364:364/6446/eaav6335. [PMID: 31221830 DOI: 10.1126/science.aav6335] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 05/16/2019] [Indexed: 12/11/2022]
Abstract
Ruminants are the only extant mammalian group possessing bony (osseous) headgear. We obtained 221 transcriptomes from bovids and cervids and sequenced three genomes representing the only two pecoran lineages that convergently lack headgear. Comparative analyses reveal that bovid horns and cervid antlers share similar gene expression profiles and a common cellular basis developed from neural crest stem cells. The rapid regenerative properties of antler tissue involve exploitation of oncogenetic pathways, and at the same time some tumor suppressor genes are under strong selection in deer. These results provide insights into the evolutionary origin of ruminant headgear as well as mammalian organ regeneration and oncogenesis.
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Affiliation(s)
- Yu Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Chenzhou Zhang
- Center for Ecological and Environmental Sciences, Northwestern Polytechnical University, Xi'an 710072, China
| | - Nini Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Zhipeng Li
- Department of Special Animal Nutrition and Feed Science, Institute of Special Animal and Plant Sciences, Chinese Academy of Agricultural Sciences, Changchun 130112, China
| | - Rasmus Heller
- Section for Computational and RNA Biology, Department of Biology, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Rong Liu
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences and Yunnan Province, Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, Yunnan 650223, China.,Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
| | - Yue Zhao
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Jiangang Han
- Institute of Animal Science (IAS), Chinese Academy of Agricultural Sciences (CAAS), Beijing 100193, China
| | - Xiangyu Pan
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Zhuqing Zheng
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Xueqin Dai
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences and Yunnan Province, Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, Yunnan 650223, China.,Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
| | - Ceshi Chen
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences and Yunnan Province, Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, Yunnan 650223, China.,Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
| | - Mingle Dou
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Shujun Peng
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Xianqing Chen
- Center for Ecological and Environmental Sciences, Northwestern Polytechnical University, Xi'an 710072, China
| | - Jing Liu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Ming Li
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Kun Wang
- Center for Ecological and Environmental Sciences, Northwestern Polytechnical University, Xi'an 710072, China
| | - Chang Liu
- Center for Ecological and Environmental Sciences, Northwestern Polytechnical University, Xi'an 710072, China
| | - Zeshan Lin
- Center for Ecological and Environmental Sciences, Northwestern Polytechnical University, Xi'an 710072, China
| | - Lei Chen
- Center for Ecological and Environmental Sciences, Northwestern Polytechnical University, Xi'an 710072, China
| | - Fei Hao
- Center of Special Environmental Biomechanics and Biomedical Engineering, School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, China
| | - Wenbo Zhu
- Center for Ecological and Environmental Sciences, Northwestern Polytechnical University, Xi'an 710072, China
| | - Chengchuang Song
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Chen Zhao
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Chengli Zheng
- Sichuan Institute of Musk Deer Breeding, Sichuan 610000, China
| | - Jianming Wang
- Sichuan Institute of Musk Deer Breeding, Sichuan 610000, China
| | - Shengwei Hu
- College of Life Sciences, Shihezi University, Shihezi, Xinjiang 832003, China
| | - Cunyuan Li
- College of Life Sciences, Shihezi University, Shihezi, Xinjiang 832003, China
| | - Hui Yang
- Center of Special Environmental Biomechanics and Biomedical Engineering, School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, China
| | - Lin Jiang
- Institute of Animal Science (IAS), Chinese Academy of Agricultural Sciences (CAAS), Beijing 100193, China
| | - Guangyu Li
- Department of Special Animal Nutrition and Feed Science, Institute of Special Animal and Plant Sciences, Chinese Academy of Agricultural Sciences, Changchun 130112, China
| | - Mingjun Liu
- The Key Laboratory of Animal Biotechnology of Xinjiang, Xinjiang Academy of Animal Science, Xinjiang, Urumqi 830026, China
| | | | - Guojie Zhang
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China.,China National GeneBank, BGI-Shenzhen, Shenzhen 518083, China.,State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China.,Section for Ecology and Evolution, Department of Biology, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Yu Jiang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
| | - Wen Wang
- Center for Ecological and Environmental Sciences, Northwestern Polytechnical University, Xi'an 710072, China. .,Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China.,State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Qiang Qiu
- Center for Ecological and Environmental Sciences, Northwestern Polytechnical University, Xi'an 710072, China.
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13
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Zhang J, Jin H, Zhang W, Ding C, O'Keeffe S, Ye M, Zuker CS. Sour Sensing from the Tongue to the Brain. Cell 2019; 179:392-402.e15. [PMID: 31543264 DOI: 10.1016/j.cell.2019.08.031] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 08/04/2019] [Accepted: 08/15/2019] [Indexed: 12/19/2022]
Abstract
The ability to sense sour provides an important sensory signal to prevent the ingestion of unripe, spoiled, or fermented foods. Taste and somatosensory receptors in the oral cavity trigger aversive behaviors in response to acid stimuli. Here, we show that the ion channel Otopetrin-1, a proton-selective channel normally involved in the sensation of gravity in the vestibular system, is essential for sour sensing in the taste system. We demonstrate that knockout of Otop1 eliminates acid responses from sour-sensing taste receptor cells (TRCs). In addition, we show that mice engineered to express otopetrin-1 in sweet TRCs have sweet cells that also respond to sour stimuli. Next, we genetically identified the taste ganglion neurons mediating each of the five basic taste qualities and demonstrate that sour taste uses its own dedicated labeled line from TRCs in the tongue to finely tuned taste neurons in the brain to trigger aversive behaviors.
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Affiliation(s)
- Jin Zhang
- Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Neuroscience, Columbia University, New York, NY 10032, USA; Mortimer B. Zukerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Hao Jin
- Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Neuroscience, Columbia University, New York, NY 10032, USA; Mortimer B. Zukerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Wenyi Zhang
- Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Neuroscience, Columbia University, New York, NY 10032, USA; Mortimer B. Zukerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Cheng Ding
- Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Neuroscience, Columbia University, New York, NY 10032, USA; Mortimer B. Zukerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Sean O'Keeffe
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Mingyu Ye
- Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Neuroscience, Columbia University, New York, NY 10032, USA; Mortimer B. Zukerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Charles S Zuker
- Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Neuroscience, Columbia University, New York, NY 10032, USA; Mortimer B. Zukerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA.
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14
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Chen Q, Zeng W, She J, Bai XC, Jiang Y. Structural and functional characterization of an otopetrin family proton channel. eLife 2019; 8:46710. [PMID: 30973323 PMCID: PMC6483595 DOI: 10.7554/elife.46710] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Accepted: 04/11/2019] [Indexed: 12/14/2022] Open
Abstract
The otopetrin (OTOP) proteins were recently characterized as proton channels. Here we present the cryo-EM structure of OTOP3 from Xenopus tropicalis (XtOTOP3) along with functional characterization of the channel. XtOTOP3 forms a homodimer with each subunit containing 12 transmembrane helices that can be divided into two structurally homologous halves; each half assembles as an α-helical barrel that could potentially serve as a proton conduction pore. Both pores open from the extracellular half before becoming occluded at a central constriction point consisting of three highly conserved residues - Gln232/585-Asp262/Asn623-Tyr322/666 (the constriction triads). Mutagenesis shows that the constriction triad from the second pore is less amenable to perturbation than that of the first pore, suggesting an unequal contribution between the two pores to proton transport. We also identified several key residues at the interface between the two pores that are functionally important, particularly Asp509, which confers intracellular pH-dependent desensitization to OTOP channels.
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Affiliation(s)
- Qingfeng Chen
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, United States.,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, United States.,Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - Weizhong Zeng
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, United States.,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, United States.,Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - Ji She
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, United States.,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Xiao-Chen Bai
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, United States.,Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Youxing Jiang
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, United States.,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, United States.,Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
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15
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Zewe JP, Wills RC, Sangappa S, Goulden BD, Hammond GR. SAC1 degrades its lipid substrate PtdIns4 P in the endoplasmic reticulum to maintain a steep chemical gradient with donor membranes. eLife 2018; 7:35588. [PMID: 29461204 PMCID: PMC5829913 DOI: 10.7554/elife.35588] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 02/13/2018] [Indexed: 12/22/2022] Open
Abstract
Gradients of PtdIns4P between organelle membranes and the endoplasmic reticulum (ER) are thought to drive counter-transport of other lipids via non-vesicular traffic. This novel pathway requires the SAC1 phosphatase to degrade PtdIns4P in a 'cis' configuration at the ER to maintain the gradient. However, SAC1 has also been proposed to act in 'trans' at membrane contact sites, which could oppose lipid traffic. It is therefore crucial to determine which mode SAC1 uses in living cells. We report that acute inhibition of SAC1 causes accumulation of PtdIns4P in the ER, that SAC1 does not enrich at membrane contact sites, and that SAC1 has little activity in 'trans', unless a linker is added between its ER-anchored and catalytic domains. The data reveal an obligate 'cis' activity of SAC1, supporting its role in non-vesicular lipid traffic and implicating lipid traffic more broadly in inositol lipid homeostasis and function.
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Affiliation(s)
- James P Zewe
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Rachel C Wills
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Sahana Sangappa
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Brady D Goulden
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Gerald Rv Hammond
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
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16
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A transcriptomic survey of Migdolus fryanus (sugarcane rhizome borer) larvae. PLoS One 2017; 12:e0173059. [PMID: 28248990 PMCID: PMC5332103 DOI: 10.1371/journal.pone.0173059] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 02/14/2017] [Indexed: 11/19/2022] Open
Abstract
Sugarcane, a major crop grown in the tropical and subtropical areas of the world, is produced mainly for sucrose, which is used as a sweetener or for the production of bioethanol. Among the numerous pests that significantly affect the yield of sugarcane, the sugarcane rhizome borer (Migdolus fryanus, a cerambycidae beetle) is known to cause severe damage to the crops in Brazil. The absence of molecular information about this insect reinforces the need for studies and an effective method to control this pest. In this study, RNA-Seq technology was employed to study different parts of M. fryanus larvae. The generated data will help in further investigations about the taxonomy, development, and adaptation of this insect. RNA was extracted from six different parts (head, fat body, integument, hindgut, midgut, and foregut) using Trizol methodology. Using Illumina paired-end sequencing technology and the Trinity platform, trimming and de novo assembly was performed, resulting in 44,567 contigs longer than 200 nt for a reunion of data from all transcriptomes, with a mean length of 1,095.27 nt. Transcripts were annotated using BLAST against different protein databanks (Uniprot/Swissprot, PFAM, KEEG, SignalP 4.1, Gene Ontology, and CAZY) and were compared for similarity using a Venn diagram. Differential expression patterns were studied for select genes through qPCR and FPKM comprising important protein families (digestive peptidases, glucosyl hydrolases, serine protease inhibitors and otopetrin), which allowed a better understanding of the insect’s digestion, immunity and gravity sensorial mechanisms.
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17
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Xu Y, Zhang Y, Lundberg YW. Spatiotemporal differences in otoconial gene expression. Genesis 2016; 54:613-625. [PMID: 27792272 DOI: 10.1002/dvg.22990] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 10/02/2016] [Accepted: 10/26/2016] [Indexed: 11/06/2022]
Abstract
Otoconia are minute biocrystals composed of glycoproteins, proteoglycans, and CaCO3 , and are indispensable for sensory processing in the utricle and saccule. Otoconia abnormalities and degeneration can cause or facilitate crystal dislocation to the ampulla, leading to vertigo and imbalance in humans. In order to better understand the molecular mechanism controlling otoconia formation and maintenance, we have examined the spatial and temporal expression differences of otoconial genes in the mouse inner ear at developmental, mature and aging stages using whole transcriptome sequencing (RNA-Seq) and quantitative RT-PCR. We show that the expression levels of most otoconial genes are much higher in the utricle and saccule compared with other inner ear tissues before postnatal stages in C57Bl/6J mice, and the expression of a few of these genes is restricted to the embryonic utricle and saccule. After the early postnatal stages, expression of all otoconial genes in the utricle and saccule is drastically reduced, while a few genes gain expression dominance in the aging ampulla, indicating a potential for ectopic debris formation in the latter tissue at old ages. The data suggest that the expression of otoconial genes is tightly regulated spatially and temporally during developmental stages and can become unregulated at aging stages. Birth Defects Research (Part A) 106:613-625, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Yinfang Xu
- Vestibular Genetics Laboratory, Center for Sensory Neuroscience, Boys Town National Research Hospital, Omaha, Nebraska, 68131, USA.,Cell Electrophysiology Laboratory, Shanghai Research Center of Acupuncture and Meridians, Shanghai, 201203, China
| | - Yan Zhang
- Vestibular Genetics Laboratory, Center for Sensory Neuroscience, Boys Town National Research Hospital, Omaha, Nebraska, 68131, USA
| | - Yunxia Wang Lundberg
- Vestibular Genetics Laboratory, Center for Sensory Neuroscience, Boys Town National Research Hospital, Omaha, Nebraska, 68131, USA
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18
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Stawicki TM, Owens KN, Linbo T, Reinhart KE, Rubel EW, Raible DW. The zebrafish merovingian mutant reveals a role for pH regulation in hair cell toxicity and function. Dis Model Mech 2015; 7:847-56. [PMID: 24973752 PMCID: PMC4073274 DOI: 10.1242/dmm.016576] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Control of the extracellular environment of inner ear hair cells by ionic transporters is crucial for hair cell function. In addition to inner ear hair cells, aquatic vertebrates have hair cells on the surface of their body in the lateral line system. The ionic environment of these cells also appears to be regulated, although the mechanisms of this regulation are less understood than those of the mammalian inner ear. We identified the merovingian mutant through genetic screening in zebrafish for genes involved in drug-induced hair cell death. Mutants show complete resistance to neomycin-induced hair cell death and partial resistance to cisplatin-induced hair cell death. This resistance is probably due to impaired drug uptake as a result of reduced mechanotransduction ability, suggesting that the mutants have defects in hair cell function independent of drug treatment. Through genetic mapping we found that merovingian mutants contain a mutation in the transcription factor gcm2. This gene is important for the production of ionocytes, which are cells crucial for whole body pH regulation in fish. We found that merovingian mutants showed an acidified extracellular environment in the vicinity of both inner ear and lateral line hair cells. We believe that this acidified extracellular environment is responsible for the defects seen in hair cells of merovingian mutants, and that these mutants would serve as a valuable model for further study of the role of pH in hair cell function.
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Affiliation(s)
- Tamara M Stawicki
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA. Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA 98195, USA
| | - Kelly N Owens
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA. Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA 98195, USA. Department of Otolaryngology, Head and Neck Surgery, University of Washington, Seattle, WA 98195, USA
| | - Tor Linbo
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Katherine E Reinhart
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Edwin W Rubel
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA 98195, USA. Department of Otolaryngology, Head and Neck Surgery, University of Washington, Seattle, WA 98195, USA
| | - David W Raible
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA. Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA 98195, USA.
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19
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Brennan RS, Galvez F, Whitehead A. Reciprocal osmotic challenges reveal mechanisms of divergence in phenotypic plasticity in the killifish Fundulus heteroclitus. J Exp Biol 2015; 218:1212-22. [DOI: 10.1242/jeb.110445] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 02/16/2015] [Indexed: 12/12/2022]
Abstract
The killifish Fundulus heteroclitus is an estuarine species with broad physiological plasticity enabling acclimation to diverse stressors. Previous work suggests freshwater populations expanded their physiology to accommodate low salinity environments, however, it is unknown if this compromises their tolerance to high salinity. We employed a comparative approach to investigate the mechanisms of a derived freshwater phenotype and the fate of an ancestral euryhaline phenotype after invasion of a freshwater environment. We compared physiological and transcriptomic responses to high and low salinity stress in fresh and brackish water populations and found an enhanced plasticity to low salinity in the freshwater population coupled with a reduced ability to acclimate to high salinity. Transcriptomic data identified genes with a conserved common response, a conserved salinity dependent response, and responses associated with population divergence. Conserved common acclimation responses revealed stress responses and alterations in cell-cycle regulation as important mechanisms in the general osmotic response. Salinity-specific responses included the regulation of genes involved in ion transport, intracellular calcium, energetic processes, and cellular remodeling. Genes diverged between populations were primarily those showing salinity-specific expression and included those regulating polyamine homeostasis and cell cycle. Additionally, when populations were matched with their native salinity, expression patterns were consistent with the concept of “transcriptomic resilience,” suggesting local adaptation. These findings provide insight into the fate of a plastic phenotype after a shift in environmental salinity and help to reveal mechanisms allowing for euryhalinity.
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Affiliation(s)
- Reid S. Brennan
- Department of Environmental Toxicology, University of California-Davis, California, 95616, USA
| | - Fernando Galvez
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Andrew Whitehead
- Department of Environmental Toxicology, University of California-Davis, California, 95616, USA
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20
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Lundberg YW, Xu Y, Thiessen KD, Kramer KL. Mechanisms of otoconia and otolith development. Dev Dyn 2014; 244:239-53. [PMID: 25255879 DOI: 10.1002/dvdy.24195] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 08/25/2014] [Accepted: 08/26/2014] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Otoconia are bio-crystals that couple mechanic forces to the sensory hair cells in the utricle and saccule, a process essential for us to sense linear acceleration and gravity for the purpose of maintaining bodily balance. In fish, structurally similar bio-crystals called otoliths mediate both balance and hearing. Otoconia abnormalities are common and can cause vertigo and imbalance in humans. However, the molecular etiology of these illnesses is unknown, as investigators have only begun to identify genes important for otoconia formation in recent years. RESULTS To date, in-depth studies of selected mouse otoconial proteins have been performed, and about 75 zebrafish genes have been identified to be important for otolith development. CONCLUSIONS This review will summarize recent findings as well as compare otoconia and otolith development. It will provide an updated brief review of otoconial proteins along with an overview of the cells and cellular processes involved. While continued efforts are needed to thoroughly understand the molecular mechanisms underlying otoconia and otolith development, it is clear that the process involves a series of temporally and spatially specific events that are tightly coordinated by numerous proteins. Such knowledge will serve as the foundation to uncover the molecular causes of human otoconia-related disorders.
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Affiliation(s)
- Yunxia Wang Lundberg
- Vestibular Genetics Laboratory, Boys Town National Research Hospital, Omaha, Nebraska
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21
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Lundberg YW, Xu Y, Thiessen KD, Kramer KL. Mechanisms of otoconia and otolith development. Dev Dyn 2014. [PMID: 25255879 DOI: 10.1002/dvdy.24195(2014)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Otoconia are bio-crystals that couple mechanic forces to the sensory hair cells in the utricle and saccule, a process essential for us to sense linear acceleration and gravity for the purpose of maintaining bodily balance. In fish, structurally similar bio-crystals called otoliths mediate both balance and hearing. Otoconia abnormalities are common and can cause vertigo and imbalance in humans. However, the molecular etiology of these illnesses is unknown, as investigators have only begun to identify genes important for otoconia formation in recent years. RESULTS To date, in-depth studies of selected mouse otoconial proteins have been performed, and about 75 zebrafish genes have been identified to be important for otolith development. CONCLUSIONS This review will summarize recent findings as well as compare otoconia and otolith development. It will provide an updated brief review of otoconial proteins along with an overview of the cells and cellular processes involved. While continued efforts are needed to thoroughly understand the molecular mechanisms underlying otoconia and otolith development, it is clear that the process involves a series of temporally and spatially specific events that are tightly coordinated by numerous proteins. Such knowledge will serve as the foundation to uncover the molecular causes of human otoconia-related disorders.
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Affiliation(s)
- Yunxia Wang Lundberg
- Vestibular Genetics Laboratory, Boys Town National Research Hospital, Omaha, Nebraska
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22
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Wang GX, Cho KW, Uhm M, Hu CR, Li S, Cozacov Z, Xu AE, Cheng JX, Saltiel AR, Lumeng CN, Lin JD. Otopetrin 1 protects mice from obesity-associated metabolic dysfunction through attenuating adipose tissue inflammation. Diabetes 2014; 63:1340-52. [PMID: 24379350 PMCID: PMC3964504 DOI: 10.2337/db13-1139] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Chronic low-grade inflammation is emerging as a pathogenic link between obesity and metabolic disease. Persistent immune activation in white adipose tissue (WAT) impairs insulin sensitivity and systemic metabolism, in part, through the actions of proinflammatory cytokines. Whether obesity engages an adaptive mechanism to counteract chronic inflammation in adipose tissues has not been elucidated. Here we identified otopetrin 1 (Otop1) as a component of a counterinflammatory pathway that is induced in WAT during obesity. Otop1 expression is markedly increased in obese mouse WAT and is stimulated by tumor necrosis factor-α in cultured adipocytes. Otop1 mutant mice respond to high-fat diet with pronounced insulin resistance and hepatic steatosis, accompanied by augmented adipose tissue inflammation. Otop1 attenuates interferon-γ (IFN-γ) signaling in adipocytes through selective downregulation of the transcription factor STAT1. Using a tagged vector, we found that Otop1 physically interacts with endogenous STAT1. Thus, Otop1 defines a unique target of cytokine signaling that attenuates obesity-induced adipose tissue inflammation and plays an adaptive role in maintaining metabolic homeostasis in obesity.
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Affiliation(s)
- Guo-Xiao Wang
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | - Kae Won Cho
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI
| | - Maeran Uhm
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
| | - Chun-Rui Hu
- Weldon School of Biomedical Engineering, Department of Chemistry, Purdue University, West Lafayette, IN
| | - Siming Li
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | - Zoharit Cozacov
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | - Acer E. Xu
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | - Ji-Xin Cheng
- Weldon School of Biomedical Engineering, Department of Chemistry, Purdue University, West Lafayette, IN
| | - Alan R. Saltiel
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
| | - Carey N. Lumeng
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI
| | - Jiandie D. Lin
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
- Corresponding author: Jiandie D. Lin,
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23
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Whitehead A, Zhang S, Roach JL, Galvez F. Common functional targets of adaptive micro- and macro-evolutionary divergence in killifish. Mol Ecol 2014; 22:3780-96. [PMID: 23841861 DOI: 10.1111/mec.12316] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Revised: 03/07/2013] [Accepted: 03/09/2013] [Indexed: 01/08/2023]
Abstract
Environmental salinity presents a key barrier to dispersal for most aquatic organisms, and adaptation to alternate osmotic environments likely enables species diversification. Little is known of the functional basis for derived tolerance to environmental salinity. We integrate comparative physiology and functional genomics to explore the mechanistic underpinnings of evolved variation in osmotic plasticity within and among two species of killifish; Fundulus majalis harbours the ancestral mainly salt-tolerant phenotype, whereas Fundulus heteroclitus harbours a derived physiology that retains extreme salt tolerance but with expanded osmotic plasticity towards the freshwater end of the osmotic continuum. Common-garden comparative hypo-osmotic challenge experiments show that F. heteroclitus is capable of remodelling gill epithelia more quickly and at more extreme osmotic challenge than F. majalis. We detect an unusual pattern of baseline transcriptome divergence, where neutral evolutionary processes appear to govern expression divergence within species, but patterns of divergence for these genes between species do not follow neutral expectations. During acclimation, genome expression profiling identifies mechanisms of acclimation-associated response that are conserved within the genus including regulation of paracellular permeability. In contrast, several responses vary among species including those putatively associated with cell volume regulation, and these same mechanisms are targets for adaptive physiological divergence along osmotic gradients within F. heteroclitus. As such, the genomic and physiological mechanisms that are associated with adaptive fine-tuning within species also contribute to macro-evolutionary divergence as species diversify across osmotic niches.
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Affiliation(s)
- Andrew Whitehead
- Department of Environmental Toxicology, University of California Davis, 4138 Meyer Hall, One Shields Avenue, Davis, CA 95616, USA.
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Whitehead A, Roach JL, Zhang S, Galvez F. Salinity- and population-dependent genome regulatory response during osmotic acclimation in the killifish (Fundulus heteroclitus) gill. ACTA ACUST UNITED AC 2012; 215:1293-305. [PMID: 22442367 DOI: 10.1242/jeb.062075] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The killifish Fundulus heteroclitus is abundant in osmotically dynamic estuaries and it can quickly adjust to extremes in environmental salinity. We performed a comparative osmotic challenge experiment to track the transcriptomic and physiological responses to two salinities throughout a time course of acclimation, and to explore the genome regulatory mechanisms that enable extreme osmotic acclimation. One southern and one northern coastal population, known to differ in their tolerance to hypo-osmotic exposure, were used as our comparative model. Both populations could maintain osmotic homeostasis when transferred from 32 to 0.4 p.p.t., but diverged in their compensatory abilities when challenged down to 0.1 p.p.t., in parallel with divergent transformation of gill morphology. Genes involved in cell volume regulation, nucleosome maintenance, ion transport, energetics, mitochondrion function, transcriptional regulation and apoptosis showed population- and salinity-dependent patterns of expression during acclimation. Network analysis confirmed the role of cytokine and kinase signaling pathways in coordinating the genome regulatory response to osmotic challenge, and also posited the importance of signaling coordinated through the transcription factor HNF-4α. These genome responses support hypotheses of which regulatory mechanisms are particularly relevant for enabling extreme physiological flexibility.
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Affiliation(s)
- Andrew Whitehead
- University of California, Davis, Environmental Toxicology Department, Davis, CA 95616, USA.
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Genomic mechanisms of evolved physiological plasticity in killifish distributed along an environmental salinity gradient. Proc Natl Acad Sci U S A 2011; 108:6193-8. [PMID: 21444822 DOI: 10.1073/pnas.1017542108] [Citation(s) in RCA: 162] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Adaptive variation tends to emerge clinally along environmental gradients or discretely among habitats with limited connectivity. However, in Atlantic killifish (Fundulus heteroclitus), a population genetic discontinuity appears in the absence of obvious barriers to gene flow along parallel salinity clines and coincides with a physiologically stressful salinity. We show that populations resident on either side of this discontinuity differ in their abilities to compensate for osmotic shock and illustrate the physiological and functional genomic basis of population variation in hypoosmotic tolerance. A population native to a freshwater habitat, upstream of the genetic discontinuity, exhibits tolerance to extreme hypoosmotic challenge, whereas populations native to brackish or marine habitats downstream of the discontinuity lose osmotic homeostasis more severely and take longer to recover. Comparative transcriptomics reveals a core transcriptional response associated with acute and acclimatory responses to hypoosmotic shock and posits unique mechanisms that enable extreme osmotic tolerance. Of the genes that vary in expression among populations, those that are putatively involved in physiological acclimation are more likely to exhibit nonneutral patterns of divergence between freshwater and brackish populations. It is not the well-known effectors of osmotic acclimation, but rather the lesser-known immediate-early responses, that appear important in contributing to population differences.
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Xu Y, Zhang H, Yang H, Zhao X, Lovas S, Lundberg YYW. Expression, functional, and structural analysis of proteins critical for otoconia development. Dev Dyn 2011; 239:2659-73. [PMID: 20803598 DOI: 10.1002/dvdy.22405] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Otoconia, developed during late gestation and perinatal stages, couple mechanic force to the sensory hair cells in the vestibule for motion detection and bodily balance. In the present work, we have investigated whether compensatory deposition of another protein(s) may have taken place to partially alleviate the detrimental effects of Oc90 deletion by analyzing a comprehensive list of plausible candidates, and have found a drastic increase in the deposition of Sparc-like 1 (aka Sc1 or hevin) in Oc90 null versus wt otoconia. We show that such up-regulation is specific to Sc1, and that stable transfection of Oc90 and Sc1 full-length expression constructs in NIH/3T3 cells indeed promotes matrix calcification. Analysis and modeling of Oc90 and Sc1 protein structures show common features that may be critical requirements for the otoconial matrix backbone protein. Such information will serve as the foundation for future regenerative purposes.
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Affiliation(s)
- Yinfang Xu
- Vestibular Neurogenetics Laboratory, Boys Town National Research Hospital, Omaha, Nebraska 68131, USA
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Hurle B, Marques-Bonet T, Antonacci F, Hughes I, Ryan JF, Eichler EE, Ornitz DM, Green ED. Lineage-specific evolution of the vertebrate Otopetrin gene family revealed by comparative genomic analyses. BMC Evol Biol 2011; 11:23. [PMID: 21261979 PMCID: PMC3038909 DOI: 10.1186/1471-2148-11-23] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 01/24/2011] [Indexed: 11/19/2022] Open
Abstract
Background Mutations in the Otopetrin 1 gene (Otop1) in mice and fish produce an unusual bilateral vestibular pathology that involves the absence of otoconia without hearing impairment. The encoded protein, Otop1, is the only functionally characterized member of the Otopetrin Domain Protein (ODP) family; the extended sequence and structural preservation of ODP proteins in metazoans suggest a conserved functional role. Here, we use the tools of sequence- and cytogenetic-based comparative genomics to study the Otop1 and the Otop2-Otop3 genes and to establish their genomic context in 25 vertebrates. We extend our evolutionary study to include the gene mutated in Usher syndrome (USH) subtype 1G (Ush1g), both because of the head-to-tail clustering of Ush1g with Otop2 and because Otop1 and Ush1g mutations result in inner ear phenotypes. Results We established that OTOP1 is the boundary gene of an inversion polymorphism on human chromosome 4p16 that originated in the common human-chimpanzee lineage more than 6 million years ago. Other lineage-specific evolutionary events included a three-fold expansion of the Otop genes in Xenopus tropicalis and of Ush1g in teleostei fish. The tight physical linkage between Otop2 and Ush1g is conserved in all vertebrates. To further understand the functional organization of the Ushg1-Otop2 locus, we deduced a putative map of binding sites for CCCTC-binding factor (CTCF), a mammalian insulator transcription factor, from genome-wide chromatin immunoprecipitation-sequencing (ChIP-seq) data in mouse and human embryonic stem (ES) cells combined with detection of CTCF-binding motifs. Conclusions The results presented here clarify the evolutionary history of the vertebrate Otop and Ush1g families, and establish a framework for studying the possible interaction(s) of Ush1g and Otop in developmental pathways.
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Affiliation(s)
- Belen Hurle
- Genome Technology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Kim E, Hyrc KL, Speck J, Salles FT, Lundberg YW, Goldberg MP, Kachar B, Warchol ME, Ornitz DM. Missense mutations in Otopetrin 1 affect subcellular localization and inhibition of purinergic signaling in vestibular supporting cells. Mol Cell Neurosci 2011; 46:655-61. [PMID: 21236346 DOI: 10.1016/j.mcn.2011.01.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 11/23/2010] [Accepted: 01/04/2011] [Indexed: 10/18/2022] Open
Abstract
Otopetrin 1 (Otop1) encodes a protein that is essential for the development of otoconia. Otoconia are the extracellular calcium carbonate containing crystals that are important for vestibular mechanosensory transduction of linear motion and gravity. There are two mutant alleles of Otop1 in mice, titled (tlt) and mergulhador (mlh), which result in non-syndromic otoconia agenesis and a consequent balance defect. Biochemically, Otop1 has been shown to modulate purinergic control of intracellular calcium in vestibular supporting cells, which could be one of the mechanisms by which Otop1 participates in the mineralization of otoconia. To understand how tlt and mlh mutations affect the biochemical function of Otop1, we examined the purinergic response of COS7 cells expressing mutant Otop1 proteins, and dissociated sensory epithelial cells from tlt and mlh mice. We also examined the subcellular localization of Otop1 in whole sensory epithelia from tlt and mlh mice. Here we show that tlt and mlh mutations uncouple Otop1 from inhibition of P2Y receptor function. Although the in vitro biochemical function of the Otop1 mutant proteins is normal, in vivo they behave as null alleles. We show that in supporting cells the apical membrane localization of the mutant Otop1 proteins is lost. These data suggest that the tlt and mlh mutations primarily affect the localization of Otop1, which interferes with its ability to interact with other proteins that are important for its cellular and biochemical function.
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Affiliation(s)
- Euysoo Kim
- Department of Developmental Biology, Washington University School of Medicine, Saint Louis, MO 63110, USA
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Whitehead A, Galvez F, Zhang S, Williams LM, Oleksiak MF. Functional genomics of physiological plasticity and local adaptation in killifish. J Hered 2010; 102:499-511. [PMID: 20581107 DOI: 10.1093/jhered/esq077] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Evolutionary solutions to the physiological challenges of life in highly variable habitats can span the continuum from evolution of a cosmopolitan plastic phenotype to the evolution of locally adapted phenotypes. Killifish (Fundulus sp.) have evolved both highly plastic and locally adapted phenotypes within different selective contexts, providing a comparative system in which to explore the genomic underpinnings of physiological plasticity and adaptive variation. Importantly, extensive variation exists among populations and species for tolerance to a variety of stressors, and we exploit this variation in comparative studies to yield insights into the genomic basis of evolved phenotypic variation. Notably, species of Fundulus occupy the continuum of osmotic habitats from freshwater to marine and populations within Fundulus heteroclitus span far greater variation in pollution tolerance than across all species of fish. Here, we explore how transcriptome regulation underpins extreme physiological plasticity on osmotic shock and how genomic and transcriptomic variation is associated with locally evolved pollution tolerance. We show that F. heteroclitus quickly acclimate to extreme osmotic shock by mounting a dramatic rapid transcriptomic response including an early crisis control phase followed by a tissue remodeling phase involving many regulatory pathways. We also show that convergent evolution of locally adapted pollution tolerance involves complex patterns of gene expression and genome sequence variation, which is confounded with body-weight dependence for some genes. Similarly, exploiting the natural phenotypic variation associated with other established and emerging model organisms is likely to greatly accelerate the pace of discovery of the genomic basis of phenotypic variation.
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Affiliation(s)
- Andrew Whitehead
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
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Kim E, Hyrc KL, Speck J, Lundberg YW, Salles FT, Kachar B, Goldberg MP, Warchol ME, Ornitz DM. Regulation of cellular calcium in vestibular supporting cells by otopetrin 1. J Neurophysiol 2010; 104:3439-50. [PMID: 20554841 DOI: 10.1152/jn.00525.2010] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Otopetrin 1 (OTOP1) is a multitransmembrane domain protein, which is essential for mineralization of otoconia, the calcium carbonate biominerals required for vestibular function, and the normal sensation of gravity. The mechanism driving mineralization of otoconia is poorly understood, but it has been proposed that supporting cells and a mechanism to maintain high concentrations of calcium are critical. Using Otop1 knockout mice and a utricular epithelial organ culture system, we show that OTOP1 is expressed at the apex of supporting cells and functions to increase cytosolic calcium in response to purinergic agonists, such as adenosine 5'-triphosphate (ATP). This is achieved by blocking mobilization of calcium from intracellular stores in an extracellular calcium-dependent manner and by mediating influx of extracellular calcium. These data support a model in which OTOP1 acts as a sensor of the extracellular calcium concentration near supporting cells and responds to ATP in the endolymph to increase intracellular calcium levels during otoconia mineralization.
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Affiliation(s)
- Euysoo Kim
- Washington University School of Medicine, Department of Developmental Biology, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
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Lu W, Zhou D, Freeman JJ, Thalmann I, Ornitz DM, Thalmann R. In vitro effects of recombinant otoconin 90 upon calcite crystal growth. Significance of tertiary structure. Hear Res 2010; 268:172-83. [PMID: 20595020 DOI: 10.1016/j.heares.2010.05.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Revised: 05/25/2010] [Accepted: 05/25/2010] [Indexed: 01/27/2023]
Abstract
Otoconia are biomineral particles of microscopic size essential for perception of gravity and maintenance of balance. Millions of older Americans are affected in their mobility, quality of life and in their health by progressive demineralization of otoconia. Currently, no effective means to prevent or counteract this process are available. Because of prohibitive anatomical and biological constraints, otoconial research is lagging far behind other systems such as bone and teeth. We have overcome these obstacles by generating otoconial matrix proteins by recombinant techniques. In the present study, we evaluated the effects of recombinant Otoconin 90 (OC90), the principal soluble matrix protein upon calcite crystal growth patterns in vitro. Our findings highlight multiple effects, including facilitation of nucleation, and inhibition of crystal growth in a concentration-dependent manner. Moreover, OC90 induces morphologic changes characteristic of native otoconia. OC90 is considerably less acidic than the prototypical invertebrate CaCO(3) -associated protein, but is nevertheless an effective modulator of calcite crystal growth. Based on homology modeling of the sPLA2-like domains of OC90, we propose that the lower density of acidic residues of the primary sequence is compensated by formation of major anionic surface clusters upon folding into tertiary conformation.
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Affiliation(s)
- Wenfu Lu
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St Louis, MO 63110, USA.
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Zhao X, Jones SM, Yamoah EN, Lundberg YW. Otoconin-90 deletion leads to imbalance but normal hearing: a comparison with other otoconia mutants. Neuroscience 2008; 153:289-99. [PMID: 18355969 DOI: 10.1016/j.neuroscience.2008.01.055] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Revised: 12/20/2007] [Accepted: 01/25/2008] [Indexed: 10/22/2022]
Abstract
Our sense of gravitation and linear acceleration is mediated by stimulation of vestibular hair cells through displacement of otoconia in the utricle and saccule (the gravity receptor organ). We recently showed that otoconin-90 (Oc90) deletion led to formation of giant otoconia. In the present study, we determined the extent to which the giant otoconia affected balance and gravity receptor sensory input and compared the findings with other otoconia mutants. We employed a wide spectrum of balance behavioral tests, including reaching and air-righting reflexes, gait, swimming, beam-crossing, rotorod latencies, and a direct measure of gravity receptor input, vestibular evoked potentials (VsEPs). All tests on homozygous adult mutants consistently ranked the order of imbalance as (from worst to best) Nox3(het)<otopetrin 1(tlt)<Oc90 null<Oc90 wild type and C57Bl/6 mice using systematic statistical comparisons of the frequency of occurrence or the severity of abnormal functions. This order coincides with the degree of otoconia deficiencies and is consistent with VsEP measures. Notably, all mice (except Nox3(het)) showed remarkable learned adaptation to peripheral vestibular deficits by staying on the rotating rod significantly longer in each successive trial, and the rate and extent of such learned improvements ranked the same order as their initial balance ability. Despite the vestibular morbidity, Oc90 null mice had normal hearing, as measured by auditory brainstem responses (ABRs) and distortion products of otoacoustic emissions (DPOAEs). The study demonstrates that the remnant otoconia mass in Oc90 nulls does stimulate the gravity receptor organs, which was likely responsible for the improved balance performance relative to strains with absent otoconia. Furthermore, the combination of direct electrophysiological measures and a series of behavioral tests can be used to interpret the imbalance severity arising from altered inputs from the gravity receptor end organ.
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Affiliation(s)
- X Zhao
- Genetics Department, Boys Town National Research Hospital, 555 North 30th Street, Omaha, NE 68131, USA
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Hughes I, Binkley J, Hurle B, Green ED, Sidow A, Ornitz DM. Identification of the Otopetrin Domain, a conserved domain in vertebrate otopetrins and invertebrate otopetrin-like family members. BMC Evol Biol 2008; 8:41. [PMID: 18254951 PMCID: PMC2268672 DOI: 10.1186/1471-2148-8-41] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Accepted: 02/06/2008] [Indexed: 11/30/2022] Open
Abstract
Background Otopetrin 1 (Otop1) encodes a multi-transmembrane domain protein with no homology to known transporters, channels, exchangers, or receptors. Otop1 is necessary for the formation of otoconia and otoliths, calcium carbonate biominerals within the inner ear of mammals and teleost fish that are required for the detection of linear acceleration and gravity. Vertebrate Otop1 and its paralogues Otop2 and Otop3 define a new gene family with homology to the invertebrate Domain of Unknown Function 270 genes (DUF270; pfam03189). Results Multi-species comparison of the predicted primary sequences and predicted secondary structures of 62 vertebrate otopetrin, and arthropod and nematode DUF270 proteins, has established that the genes encoding these proteins constitute a single family that we renamed the Otopetrin Domain Protein (ODP) gene family. Signature features of ODP proteins are three "Otopetrin Domains" that are highly conserved between vertebrates, arthropods and nematodes, and a highly constrained predicted loop structure. Conclusion Our studies suggest a refined topologic model for ODP insertion into the lipid bilayer of 12 transmembrane domains, and highlight conserved amino-acid residues that will aid in the biochemical examination of ODP family function. The high degree of sequence and structural similarity of the ODP proteins may suggest a conserved role in the intracellular trafficking of calcium and the formation of biominerals.
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Affiliation(s)
- Inna Hughes
- Department of Developmental Biology, Washington University School of Medicine, St, Louis, MO 63110, USA.
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