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Ren H, Zhang R, Zhang H, Bian C. Ecnomotopic olfactory receptors in metabolic regulation. Biomed Pharmacother 2024; 179:117403. [PMID: 39241572 DOI: 10.1016/j.biopha.2024.117403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2024] [Revised: 08/22/2024] [Accepted: 09/02/2024] [Indexed: 09/09/2024] Open
Abstract
Olfactory receptors are seven-transmembrane G-protein-coupled receptors on the cell surface. Over the past few decades, evidence has been mounting that olfactory receptors are not unique to the nose and that their ectopic existence plays an integral role in extranasal diseases. Coupled with the discovery of many natural or synthetic odor-compound ligands, new roles of ecnomotopic olfactory receptors regulating blood glucose, obesity, blood pressure, and other metabolism-related diseases are emerging. Many well-known scientific journals have called for attention to extranasal functions of ecnomotopic olfactory receptors. Thus, the prospect of ecnomotopic olfactory receptors in drug target research has been greatly underestimated. Here, we have provided an overview for the role of ecnomotopic olfactory receptors in metabolic diseases, focusing on their effects on various metabolic tissues, and discussed the possible molecular biological and pathophysiological mechanisms, which provide the basis for drug development and clinical application targeting the function of ecnomotopic olfactory receptors via literature machine learning and screening.
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Affiliation(s)
- Huiwen Ren
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, Liaoning 116044, China
| | - Ruijing Zhang
- Department of Nephrology, Xijing Hospital, the Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Haibo Zhang
- Departments of Infectious Disease, the Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang 712000, China
| | - Che Bian
- Department of General Medicine, the Fourth Affiliated Hospital of China Medical University, Shenyang 110032, China.
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Koloi S, Ganguly I, Singh S, Dixit S. Whole genome re-sequencing reveals high altitude adaptation signatures and admixture in Ladakhi cattle. Gene 2024; 933:148957. [PMID: 39306203 DOI: 10.1016/j.gene.2024.148957] [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: 09/14/2023] [Revised: 08/19/2024] [Accepted: 09/18/2024] [Indexed: 10/01/2024]
Abstract
Ladakhi cattle, native to the high-altitude region of Ladakh in northern India (ranging from 3,000 to 5,000 m above sea level), have evolved unique genetic adaptations to thrive in harsh environmental conditions, such as hypoxia, extreme cold, and low humidity. This study explored the genome of Ladakhi cattle to investigate genetic structure, selection signatures, and adaptive mechanisms. Whole genome sequencing reads, generated on Illumina NovaSeq 6000 platform, were aligned to the Bos taurus reference genome with BWA-MEM. SNPs were identified and filtered using GATK and bcftools, and functionally annotated with SnpEff. For population genomic analysis, PCA and admixture modeling assessed genetic structure, while Neighbor-Joining trees, LD decay, nucleotide diversity (π), and FST evaluated phylogenetic relationships and genetic variation. Selective sweeps were detected using RAiSD, and gene-set enrichment and protein-protein interaction analyses were conducted to explore functional pathways related to adaptation. The study revealed 3,759,279 unique SNPs and demonstrated that Ladakhi cattle form a distinct genetic cluster with an estimated admixture of 68 % Bos indicus and 32 % Bos taurus ancestry. Key findings include rapid linkage disequilibrium decay, low inbreeding level, and the identification of selection signatures and genes associated with hypoxia response, energy metabolism, and cold adaptation. Mean nucleotide diversity (π, 0.0037) and FST values indicated moderate genetic differentiation from other breeds. The analysis highlighted selection signatures for genes like HIF1A, ENO4, ANGPT1, EPO, NOS3, MAPK3, HMOX1, BCL2,CAMK2D, MTOR, AKT2,PIK3CB, and MAP2K1, among others, including various keratin and heat shock proteins. The interaction between genes associated with hypoxia signaling (HIF-1) and other enriched pathways such as PI3K, mTOR, NFκB, ERK, and ER stress, reveals a complex mechanism for managing hypoxic stress in Ladakhi cattle. These findings offer valuable insights for breeding programs aimed at enhancing livestock resilience in extreme environments and enhance understanding of mammalian adaptation to high-altitude conditions.
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Affiliation(s)
- Subrata Koloi
- Division of Animal Genetics, ICAR-National Bureau of Animal Genetic Resources, Karnal 132001, India; Division of Animal Genetics and Breeding, ICAR-National Dairy Research Institute, Karnal 132001, India
| | - Indrajit Ganguly
- Division of Animal Genetics, ICAR-National Bureau of Animal Genetic Resources, Karnal 132001, India.
| | - Sanjeev Singh
- Division of Animal Genetics, ICAR-National Bureau of Animal Genetic Resources, Karnal 132001, India
| | - Satpal Dixit
- Division of Animal Genetics, ICAR-National Bureau of Animal Genetic Resources, Karnal 132001, India.
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3
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Shi K, Jiao Y, Yang L, Yuan G, Jia J. New insights into the roles of olfactory receptors in cardiovascular disease. Mol Cell Biochem 2024; 479:1615-1626. [PMID: 38761351 DOI: 10.1007/s11010-024-05024-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 04/26/2024] [Indexed: 05/20/2024]
Abstract
Olfactory receptors (ORs) are G protein coupled receptors (GPCRs) with seven transmembrane domains that bind to specific exogenous chemical ligands and transduce intracellular signals. They constitute the largest gene family in the human genome. They are expressed in the epithelial cells of the olfactory organs and in the non-olfactory tissues such as the liver, kidney, heart, lung, pancreas, intestines, muscle, testis, placenta, cerebral cortex, and skin. They play important roles in the normal physiological and pathophysiological mechanisms. Recent evidence has highlighted a close association between ORs and several metabolic diseases. Cardiovascular diseases (CVDs) are the leading cause of morbidity and mortality globally. Furthermore, ORs play an essential role in the development and functional regulation of the cardiovascular system and are implicated in the pathophysiological mechanisms of CVDs, including atherosclerosis (AS), heart failure (HF), aneurysms, and hypertension (HTN). This review describes the specific mechanistic roles of ORs in the CVDs, and highlights the future clinical application prospects of ORs in the diagnosis, treatment, and prevention of the CVDs.
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Affiliation(s)
- Kangru Shi
- Department of Endocrinology and Metabolissm, The Affiliated Hospital of Jiangsu University, Institute of Endocrine and Metabolic Diseases, Jiangsu University, Zhenjiang, Jiangsu, China
| | - Yang Jiao
- Department of Endocrinology and Metabolissm, The Affiliated Hospital of Jiangsu University, Institute of Endocrine and Metabolic Diseases, Jiangsu University, Zhenjiang, Jiangsu, China
| | - Ling Yang
- Department of Endocrinology and Metabolissm, The Affiliated Hospital of Jiangsu University, Institute of Endocrine and Metabolic Diseases, Jiangsu University, Zhenjiang, Jiangsu, China
| | - Guoyue Yuan
- Department of Endocrinology and Metabolissm, The Affiliated Hospital of Jiangsu University, Institute of Endocrine and Metabolic Diseases, Jiangsu University, Zhenjiang, Jiangsu, China.
| | - Jue Jia
- Department of Endocrinology and Metabolissm, The Affiliated Hospital of Jiangsu University, Institute of Endocrine and Metabolic Diseases, Jiangsu University, Zhenjiang, Jiangsu, China.
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Kang T, Zhu L, Xue Y, Yang Q, Lei Q, Wang Q. Overexpression of olfactory receptor 78 ameliorates brain injury in cerebral ischaemia-reperfusion rats by activating Prkaca-mediated cAMP/PKA-MAPK pathway. J Cell Mol Med 2024; 28:e18366. [PMID: 38856956 PMCID: PMC11163950 DOI: 10.1111/jcmm.18366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 04/01/2024] [Accepted: 04/16/2024] [Indexed: 06/11/2024] Open
Abstract
Ischemic stroke is one of the main causes of disability and death. However, recanalization of occluded cerebral arteries is effective only within a very narrow time window. Therefore, it is particularly important to find neuroprotective biological targets for cerebral artery recanalization. Here, gene expression profiles of datasets GSE160500 and GSE97537 were downloaded from the GEO database, which were related to ischemic stroke in rats. Olfactory receptor 78 (Olfr78) was screened, and which highly associated with Calcium signalling pathway and MAPK pathway. Interacting protein of Olfr78, Prkaca, was predicted by STRING, and their interaction was validated by Co-IP analysis. Then, a rat model of middle cerebral artery occlusion/reperfusion (MCAO/R) and a neuronal cell model stimulated by oxygen-glucose deprivation/reoxygenation (OGD/R) were constructed, and the results showed that expression of Olfr78 and Prkaca was downregulated in MCAO rats and OGD/R-stimulated neurons. Overexpression of Olfr78 or Prkaca inhibited the secretion of inflammatory factors, Ca2+ overload, and OGD/R-induced neuronal apoptosis. Moreover, Overexpression of Prkaca increased protein levels of cAMP, PKA and phosphorylated p38 in OGD/R-stimulated neurons, while SB203580, a p38 inhibitor, treatment inhibited activation of the cAMP/PKA-MAPK pathway and counteracted the effect of Olfr78 overexpression on improvement of neuronal functions. Meanwhile, overexpression of Olfr78 or Prkaca markedly inhibited neuronal apoptosis and improved brain injury in MCAO/R rats. In conclusion, overexpression of Olfr78 inhibited Ca2+ overload and reduced neuronal apoptosis in MCAO/R rats by promoting Prkaca-mediated activation of the cAMP/PKA-MAPK pathway, thereby improving brain injury in cerebral ischaemia-reperfusion.
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Affiliation(s)
- Tao Kang
- Department of NeurologyShaanxi Provincial People's HospitalXi'anChina
| | - Lijuan Zhu
- Department of AnesthesiaShaanxi Provincial People's HospitalXi'anChina
| | - Yanli Xue
- Department of NeurologyShaanxi Provincial People's HospitalXi'anChina
| | - Qian Yang
- Department of NeurologyShaanxi Provincial People's HospitalXi'anChina
| | - Qi Lei
- Department of NeurologyShaanxi Provincial People's HospitalXi'anChina
| | - Qianqian Wang
- Department of Traditional Chinese MedicineThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'anChina
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Beito MR, Ashraf S, Odogwu D, Harmancey R. Role of Ectopic Olfactory Receptors in the Regulation of the Cardiovascular-Kidney-Metabolic Axis. Life (Basel) 2024; 14:548. [PMID: 38792570 PMCID: PMC11122380 DOI: 10.3390/life14050548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 04/19/2024] [Accepted: 04/22/2024] [Indexed: 05/26/2024] Open
Abstract
Olfactory receptors (ORs) represent one of the largest yet least investigated families of G protein-coupled receptors in mammals. While initially believed to be functionally restricted to the detection and integration of odors at the olfactory epithelium, accumulating evidence points to a critical role for ectopically expressed ORs in the regulation of cellular homeostasis in extranasal tissues. This review aims to summarize the current state of knowledge on the expression and physiological functions of ectopic ORs in the cardiovascular system, kidneys, and primary metabolic organs and emphasizes how altered ectopic OR signaling in those tissues may impact cardiovascular-kidney-metabolic health.
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Affiliation(s)
| | | | | | - Romain Harmancey
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA; (M.R.B.); (S.A.); (D.O.)
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Wu C, Xu M, Dong J, Cui W, Yuan S. The structure and function of olfactory receptors. Trends Pharmacol Sci 2024; 45:268-280. [PMID: 38296675 DOI: 10.1016/j.tips.2024.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 02/02/2024]
Abstract
Olfactory receptors (ORs) form the most important chemosensory receptor family responsible for our sense of smell in the nasal olfactory epithelium. This receptor family belongs to the class A G protein-coupled receptors (GPCRs). Recent research has indicated that ORs are involved in many nonolfactory physiological processes in extranasal tissue, such as the brain, pancreas, and testes, and implies the possible role of their dysregulation in various diseases. The recently released structures of OR51E2 and consensus OR52 have also unveiled the uniqueness of ORs from other class A GPCR members. In this review, we discuss these recent developments and computational modeling efforts toward understanding the structural properties of unresolved ORs, which could guide potential future OR-targeted drug discovery.
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Affiliation(s)
- Chenyang Wu
- The AlphaMol-SIAT Joint Laboratory, Shenzhen 518055, China; The Research Center for Computer-aided Drug Discovery, The Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Marc Xu
- The AlphaMol-SIAT Joint Laboratory, Shenzhen 518055, China; The Research Center for Computer-aided Drug Discovery, The Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Junlin Dong
- The AlphaMol-SIAT Joint Laboratory, Shenzhen 518055, China; The Research Center for Computer-aided Drug Discovery, The Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenqiang Cui
- The AlphaMol-SIAT Joint Laboratory, Shenzhen 518055, China
| | - Shuguang Yuan
- The AlphaMol-SIAT Joint Laboratory, Shenzhen 518055, China; AlphaMol Science Ltd, Shenzhen 518055, China.
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Peng YJ, Nanduri J, Wang N, Kumar GK, Bindokas V, Paul BD, Chen X, Fox AP, Vignane T, Filipovic MR, Prabhakar NR. Hypoxia sensing requires H 2S-dependent persulfidation of olfactory receptor 78. SCIENCE ADVANCES 2023; 9:eadf3026. [PMID: 37406126 PMCID: PMC10321732 DOI: 10.1126/sciadv.adf3026] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 05/31/2023] [Indexed: 07/07/2023]
Abstract
Oxygen (O2) sensing by the carotid body is critical for maintaining cardiorespiratory homeostasis during hypoxia. Hydrogen sulfide (H2S) signaling is implicated in carotid body activation by low O2. Here, we show that persulfidation of olfactory receptor 78 (Olfr78) by H2S is an integral component of carotid body activation by hypoxia. Hypoxia and H2S increased persulfidation in carotid body glomus cells and persulfidated cysteine240 in Olfr78 protein in heterologous system. Olfr78 mutants manifest impaired carotid body sensory nerve, glomus cell, and breathing responses to H2S and hypoxia. Glomus cells are positive for GOlf, adenylate cyclase 3 (Adcy3) and cyclic nucleotide-gated channel alpha 2 (Cnga2), key molecules of odorant receptor signaling. Adcy3 or Cnga2 mutants exhibited impaired carotid body and glomus cell responses to H2S and breathing responses to hypoxia. These results suggest that H2S through redox modification of Olfr78 participates in carotid body activation by hypoxia to regulate breathing.
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Affiliation(s)
- Ying-Jie Peng
- Institute for Integrative Physiology, Biological Sciences Division, University of Chicago, Chicago, IL, USA
| | - Jayasri Nanduri
- Institute for Integrative Physiology, Biological Sciences Division, University of Chicago, Chicago, IL, USA
| | - Ning Wang
- Institute for Integrative Physiology, Biological Sciences Division, University of Chicago, Chicago, IL, USA
| | - Ganesh K. Kumar
- Institute for Integrative Physiology, Biological Sciences Division, University of Chicago, Chicago, IL, USA
| | - Vytautas Bindokas
- Department of Physiology and Pharmacological Sciences, Biological Sciences Division, University of Chicago, Chicago, IL, USA
| | - Bindu D. Paul
- Department of Pharmacology, The Johns Hopkins University, Baltimore, MD, USA
| | - Xuanmao Chen
- Department of Molecular, Cellular and Biomedical Sciences, College of Life Sciences and Agriculture, University of New Hampshire, Durham, NH USA
| | - Aaron P. Fox
- Department of Physiology and Pharmacological Sciences, Biological Sciences Division, University of Chicago, Chicago, IL, USA
| | - Thibaut Vignane
- Leibniz-Institut für Analytische Wissenschaften–ISAS, Bunsen-Kirchhoff-Straße, 1144139 Dortmund, Germany
| | - Milos R. Filipovic
- Leibniz-Institut für Analytische Wissenschaften–ISAS, Bunsen-Kirchhoff-Straße, 1144139 Dortmund, Germany
| | - Nanduri R. Prabhakar
- Institute for Integrative Physiology, Biological Sciences Division, University of Chicago, Chicago, IL, USA
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Bojic SC, Ladjevic NG, Stevanovic PD, Soldatovic IA. Could Olfactory Dysfunction Help Us Diagnose Acute Mountain Sickness? Wilderness Environ Med 2023; 34:120-121. [PMID: 36610918 DOI: 10.1016/j.wem.2022.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 10/26/2022] [Accepted: 11/07/2022] [Indexed: 01/07/2023]
Affiliation(s)
- Suzana C Bojic
- Faculty of Medicine, University of Belgrade, and Department of Anesthesiology and Intensive Care, CHC "Dr. Dragisa Misović - Dedinje", Belgrade, Serbia
| | - Nebojsa G Ladjevic
- Faculty of Medicine, University of Belgrade, and Department of Anesthesiology and Intensive Care, University Clinical Center of Serbia, Belgrade, Serbia
| | - Predrag D Stevanovic
- Faculty of Medicine, University of Belgrade, and Department of Anesthesiology and Intensive Care, CHC "Dr. Dragisa Misović - Dedinje", Belgrade, Serbia
| | - Ivan A Soldatovic
- Faculty of Medicine, University of Belgrade, and Institute of Medical Statistics and Informatics, Belgrade, Serbia
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Gray OA, Yoo J, Sobreira DR, Jousma J, Witonsky D, Sakabe NJ, Peng YJ, Prabhakar NR, Fang Y, Nobréga MA, Di Rienzo A. A pleiotropic hypoxia-sensitive EPAS1 enhancer is disrupted by adaptive alleles in Tibetans. SCIENCE ADVANCES 2022; 8:eade1942. [PMID: 36417539 PMCID: PMC9683707 DOI: 10.1126/sciadv.ade1942] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 10/25/2022] [Indexed: 06/16/2023]
Abstract
In Tibetans, noncoding alleles in EPAS1-whose protein product hypoxia-inducible factor 2α (HIF-2α) drives the response to hypoxia-carry strong signatures of positive selection; however, their functional mechanism has not been systematically examined. Here, we report that high-altitude alleles disrupt the activity of four EPAS1 enhancers in one or more cell types. We further characterize one enhancer (ENH5) whose activity is both allele specific and hypoxia dependent. Deletion of ENH5 results in down-regulation of EPAS1 and HIF-2α targets in acute hypoxia and in a blunting of the transcriptional response to sustained hypoxia. Deletion of ENH5 in mice results in dysregulation of gene expression across multiple tissues. We propose that pleiotropic adaptive effects of the Tibetan alleles in EPAS1 underlie the strong selective signal at this gene.
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Affiliation(s)
- Olivia A. Gray
- Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA
| | - Jennifer Yoo
- Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA
- Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, The University of Chicago, Chicago, IL 60637, USA
- Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Débora R. Sobreira
- Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA
| | - Jordan Jousma
- Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA
| | - David Witonsky
- Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA
| | - Noboru J. Sakabe
- Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA
| | - Ying-Jie Peng
- Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, The University of Chicago, Chicago, IL 60637, USA
| | - Nanduri R. Prabhakar
- Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, The University of Chicago, Chicago, IL 60637, USA
| | - Yun Fang
- Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Marcelo A. Nobréga
- Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA
| | - Anna Di Rienzo
- Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA
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Nakashima A, Nakashima N, Nakashima K, Takano M. Olfactory receptor 78 is expressed in hypothalamic vasopressin/oxytocin neurons, parenchymal microglia and choroidal macrophages in mice. Mol Brain 2022; 15:29. [PMID: 35379313 PMCID: PMC8981654 DOI: 10.1186/s13041-022-00917-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 03/25/2022] [Indexed: 11/10/2022] Open
Abstract
Olfactory receptors have been detected in extraolfactory organs. Olfactory receptor 78 (Olfr78), proposed to respond to small organic acids, is widely expressed in the kidney, arterioles, colon, and prostate. However, its expression patterns in the brain remain largely unknown. Using immunohistochemistry, we revealed that Olfr78 was densely expressed in the hypothalamus and choroid plexus and sparsely expressed throughout the parenchyma. By costaining with cellular markers, we further found that Olfr78 was expressed in the somata and axons of vasopressin/oxytocin neurons in the hypothalamic paraventricular/supraoptic nuclei. Olfr78 was also strongly expressed in macrophages in the choroid plexus and moderately expressed in microglia near the parenchymal vasculature. Considering that these brain regions should communicate with cerebral blood flow, Olfr78 could contribute to sensing the humoral conditions surrounding the cerebrovascular system.
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Adaptive cardiorespiratory changes to chronic continuous and intermittent hypoxia. HANDBOOK OF CLINICAL NEUROLOGY 2022; 188:103-123. [PMID: 35965023 PMCID: PMC9906984 DOI: 10.1016/b978-0-323-91534-2.00009-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
This chapter reviews cardiorespiratory adaptations to chronic hypoxia (CH) experienced at high altitude and cardiorespiratory pathologies elicited by chronic intermittent hypoxia (CIH) occurring with obstructive sleep apnea (OSA). Short-term CH increases breathing (ventilatory acclimatization to hypoxia) and blood pressure (BP) through carotid body (CB) chemo reflex. Hyperplasia of glomus cells, alterations in ion channels, and recruitment of additional excitatory molecules are implicated in the heightened CB chemo reflex by CH. Transcriptional activation of hypoxia-inducible factors (HIF-1 and 2) is a major molecular mechanism underlying respiratory adaptations to short-term CH. High-altitude natives experiencing long-term CH exhibit blunted hypoxic ventilatory response (HVR) and reduced BP due to desensitization of CB response to hypoxia and impaired processing of CB sensory information at the central nervous system. Ventilatory changes evoked by long-term CH are not readily reversed after return to sea level. OSA patients and rodents subjected to CIH exhibit heightened CB chemo reflex, increased hypoxic ventilatory response, and hypertension. Increased generation of reactive oxygen species (ROS) is a major cellular mechanism underlying CIH-induced enhanced CB chemo reflex and the ensuing cardiorespiratory pathologies. ROS generation by CIH is mediated by nontranscriptional, disrupted HIF-1 and HIF-2-dependent transcriptions as well as epigenetic mechanisms.
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