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Toebbe JT, Genter MB. An Update on Sphingosine-1-Phosphate and Lysophosphatidic Acid Receptor Transcripts in Rodent Olfactory Mucosa. Int J Mol Sci 2022; 23:ijms23084343. [PMID: 35457160 PMCID: PMC9032240 DOI: 10.3390/ijms23084343] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/01/2022] [Accepted: 04/08/2022] [Indexed: 02/04/2023] Open
Abstract
Olfactory neurons connect the external environment and the brain, allowing the translocation of materials from the nasal cavity into the brain. The olfactory system is involved in SARS-CoV-2 infections; early in the pandemic declared in 2020, a loss of the sense of smell was found in many infected patients. Attention has also been focused on the role that the olfactory epithelium appears to play in the entry of the SARS-CoV-2 virus into the brain. Specifically, SARS-CoV-2 enters cells via the angiotensin-converting enzyme 2 protein (ACE2), which is found on supporting cells in the olfactory epithelium. The intranasal administration of sphingosine has been proposed to prevent the binding of SARS-CoV-2 to ACE2. Further, sphingosine-1-phosphate (S1P) receptors appear to facilitate the entry of SARS-CoV-2 into the brain. The goal of these studies was to characterize S1P receptor expression status in rodent olfactory mucosa. The expression of receptors for a related sphingolipid, lysophosphatidic acid (LPA), was also assessed. The results confirm previous reports of S1P1 and S1P3 receptor expression, as well as LPA receptor 1, in mouse olfactory mucosa; moreover, they extend the previous findings to identify additional S1P and LPA receptor transcripts in rat and mouse olfactory mucosa, as well as in cultured olfactory neurons. These findings may enhance the utility of rodent models in identifying agonists and/or antagonists of S1P and LPA receptors that may block the entry of SARS-CoV-2 and other viruses into nasal epithelial cells, and prevent transmission from the nasal cavity into the brain.
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Genter MB. Greetings to You in 2022! May We All Have an Amazing Year! Int J Toxicol 2021; 41:3-4. [PMID: 34839749 DOI: 10.1177/10915818211061891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Brown JM, Baker LS, Seroogy KB, Genter MB. Intranasal Carnosine Mitigates α-Synuclein Pathology and Motor Dysfunction in the Thy1-aSyn Mouse Model of Parkinson's Disease. ACS Chem Neurosci 2021; 12:2347-2359. [PMID: 34138535 PMCID: PMC9996643 DOI: 10.1021/acschemneuro.1c00096] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Parkinson's disease (PD) is a debilitating neurodegenerative disorder. Early symptoms include motor dysfunction and impaired olfaction. Toxic aggregation of α-synuclein (aSyn) in the olfactory bulb (OB) and substantia nigra pars compacta (SNpc) is a hallmark of PD neuropathology. Intranasal (IN) carnosine (2 mg/d for 8 weeks) was previously demonstrated to improve motor behavior and mitochondrial function in Thy1-aSyn mice, a model of PD. The present studies evaluated the efficacy of IN carnosine at a higher dose in slowing progression of motor deficits and aSyn accumulation in Thy1-aSyn mice. After baseline neurobehavioral assessments, IN carnosine was administered (0.0, 2.0, or 4.0 mg/day) to wild-type and Thy1-aSyn mice for 8 weeks. Olfactory and motor behavioral measurements were repeated prior to end point tissue collection. Brain sections were immunostained for aSyn and tyrosine hydroxylase (TH). Immunopositive cells were counted using design-based stereology in the SNpc and OB mitral cell layer (MCL). Behavioral assessments revealed a dose-dependent improvement in motor function with increasing carnosine dose. Thy1-aSyn mice treated with 2.0 or 4.0 mg/d IN carnosine exhibited fewer aSyn-positive (aSyn(+)) cell bodies in the SNpc compared to vehicle-treated mice. Moreover, the number of aSyn(+) cell bodies in carnosine-treated Thy1-aSyn mice was reduced to vehicle-treated wild-type levels in the SNpc. Carnosine treatment did not affect the number of aSyn(+) cell bodies in the OB-MCL or the number of TH(+) cells in the SNpc. In summary, intranasal carnosine treatment decreased aSyn accumulation in the SNpc, which may underlie its mitigation of motor deficits in the Thy1-aSyn mice.
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Affiliation(s)
- Josephine M Brown
- Department of Environmental and Public Health Sciences, College of Medicine, University of Cincinnati, 160 Panzeca Way, Cincinnati, Ohio 45267-0056, United States
| | - Lauren S Baker
- Department of Environmental and Public Health Sciences, College of Medicine, University of Cincinnati, 160 Panzeca Way, Cincinnati, Ohio 45267-0056, United States
| | - Kim B Seroogy
- Department of Neurology and Rehabilitation Medicine, College of Medicine, University of Cincinnati, Cincinnati, Ohio 45267-0536, United States
| | - Mary Beth Genter
- Department of Environmental and Public Health Sciences, College of Medicine, University of Cincinnati, 160 Panzeca Way, Cincinnati, Ohio 45267-0056, United States
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Affiliation(s)
- Mary Beth Genter
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH, USA.,International Journal of Toxicology
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Affiliation(s)
- Mary Beth Genter
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH, USA.,Editor-in-Chief, International Journal of Toxicology
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Bermúdez ML, Seroogy KB, Genter MB. Evaluation of Carnosine Intervention in the Thy1-aSyn Mouse Model of Parkinson's Disease. Neuroscience 2019; 411:270-278. [PMID: 31125602 DOI: 10.1016/j.neuroscience.2019.05.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 05/03/2019] [Accepted: 05/13/2019] [Indexed: 11/20/2022]
Abstract
Parkinson disease (PD) is a leading neurodegenerative disease, with multifaceted interacting mechanisms. The Thy1-aSyn mouse model of PD exhibits many features of PD patients, including sensorimotor and olfactory dysfunction and protein aggregation. Here, we tested the hypothesis that the dipeptide carnosine, which has anti-aggregating and metal-chelating properties, would provide beneficial effects on the motor and olfactory deficits observed in Thy1-aSyn mice. After 2 months of daily treatment with either intranasal (2 mg/day) or oral (10 mM in drinking water) carnosine, Thy1-aSyn mice and wild-type BDF1 mice were assessed for sensorimotor (challenging beam traversal test and spontaneous activity) and olfactory (buried pellet test) function. In addition, the olfactory epithelium was evaluated immunohistochemically for expression of alpha-synuclein (aSyn) and the carnosine transporter Pept2. Olfactory function was unaffected by carnosine treatment via either administration route. In contrast, intranasal carnosine prevented the normal decline in gait function seen in the challenging beam test in the Thy1-aSyn mice. Moreover, carnosine-treated Thy1-aSyn mice exhibited decreased aSyn immunostaining in the olfactory epithelium compared to vehicle-treated Thy1-aSyn mice, and the carnosine transporter Pept2 was immunolocalized to the apical surface of the olfactory epithelium. These findings demonstrate that intranasal carnosine shows promise in slowing the progression of motor deficits and aSyn deposition in PD.
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Affiliation(s)
- Mei-Ling Bermúdez
- Department of Environmental Health, University of Cincinnati, ML 670056, Cincinnati, OH 45267-0056, USA
| | - Kim B Seroogy
- Department of Neurology, University of Cincinnati, Medical Sciences Building, ML 0536, Cincinnati, OH 45267-0536, USA
| | - Mary Beth Genter
- Department of Environmental Health, University of Cincinnati, ML 670056, Cincinnati, OH 45267-0056, USA.
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Abstract
This review addresses the adverse influences of neurotoxic exposures on the ability to smell and taste. These chemical senses largely determine the flavor of foods and beverages, impact food intake, and ultimately nutrition, and provide a warning for spoiled or poisonous food, leaking natural gas, smoke, airborne pollutants, and other hazards. Hence, toxicants that damage these senses have a significant impact on everyday function. As noted in detail, a large number of toxicants encountered in urban and industrial air pollution, including smoke, solvents, metals, and particulate matter can alter the ability to smell. Their influence on taste, i.e., sweet, sour, bitter, salty, and savory (umami) sensations, is not well documented. Given the rather direct exposure of olfactory receptors to the outside environment, olfaction is particularly vulnerable to damage from toxicants. Some toxicants, such as nanoparticles, have the potential to damage not only the olfactory receptor cells, but also the central nervous system structures by their entrance into the brain through the olfactory mucosa.
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Affiliation(s)
- Mary Beth Genter
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH, United States
| | - Richard L Doty
- Smell and Taste Center and Department of Otorhinolaryngology: Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.
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Bermúdez ML, Skelton MR, Genter MB. Intranasal carnosine attenuates transcriptomic alterations and improves mitochondrial function in the Thy1-aSyn mouse model of Parkinson's disease. Mol Genet Metab 2018; 125:305-313. [PMID: 30146452 DOI: 10.1016/j.ymgme.2018.08.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 08/07/2018] [Indexed: 12/17/2022]
Abstract
Mitochondrial dysfunction plays a central role in the pathogenesis of neurodegenerative diseases such as Parkinson's disease (PD). This study was designed to determine whether the dipeptide carnosine, which has been shown to protect against oxidative stress and mitochondrial dysfunction, would provide a beneficial effect on mitochondrial function in the Thy1-aSyn mouse model of PD. Thy1-aSyn mice, which overexpress wild-type human alpha-synuclein (aSyn), exhibit progressive non-motor and motor deficits as early as 2 months of age. Two-month old Thy1-aSyn mice and wild-type littermates were randomly assigned to treatment groups with intranasal (IN) and drinking water carnosine, with controls receiving 10 μl of sterile waster intranasally or carnosine-free drinking water, respectively. After two months of treatment, mice were euthanized, and the midbrain was dissected for the evaluation of the gene expression and mitochondrial function. Transcriptional deficiencies associated with the aSyn overexpression in Thy1-aSyn mice were related to ribosomal and mitochondrial function. These deficiencies were attenuated by IN carnosine administration, which increased the expression of mitochondrial genes and enhanced mitochondrial function. These results suggest a potential neuroprotective role for IN-carnosine in PD patients.
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Affiliation(s)
- Mei-Ling Bermúdez
- Department of Environmental Health, University of Cincinnati, ML 670056, Cincinnati, OH 45267-0056, United States of America.
| | - Matthew R Skelton
- Department of Pediatrics, UC COM, Division of Neurology, Cincinnati Children's Research Foundation, 3333 Burnet Avenue, MLC 7044, Cincinnati, OH 45229-3039, United States of America
| | - Mary Beth Genter
- Department of Environmental Health, University of Cincinnati, ML 670056, Cincinnati, OH 45267-0056, United States of America.
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Genter MB, Zoetis T. Editor’s Note. Int J Toxicol 2017; 36:183-184. [DOI: 10.1177/1091581817711953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Mary Beth Genter
- Editor-in-Chief, International Journal of Toxicology
- University of Cincinnati, Cincinnati, OH, USA
| | - Tracey Zoetis
- President, American College of Toxicology
- Director, SciLucent, LLC, Herndon, VA, USA
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Genter MB. Editor’s Note. Int J Toxicol 2017; 36:103. [DOI: 10.1177/1091581817703356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Hsieh H, Horwath MC, Genter MB. Zinc gluconate toxicity in wild-type vs. MT1/2-deficient mice. Neurotoxicology 2016; 58:130-136. [PMID: 27979773 DOI: 10.1016/j.neuro.2016.12.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 12/08/2016] [Accepted: 12/09/2016] [Indexed: 10/20/2022]
Abstract
Previous studies have suggested that oral zinc supplementation can help reduce the duration of the common cold; however, the use of intranasal (IN) zinc is strongly associated with anosmia, or the loss of the sense of smell, in humans. Prior studies from this lab showed that upregulation of metallothioneins (MT) is a rapid and robust response to zinc gluconate (ZG). Therefore, we assessed the role of MT in the recovery of nasal epithelial damage resulting from IN zinc administration. The main studies in this investigation used a high dose of ZG (170mM) to ensure ablation of the olfactory mucosa, so that the progression of histological and functional recovery could be assessed. In vivo studies using wild-type, MT1/2 knockout mice (MT KO), and heterozygotes administered ZG by IN instillation showed profound loss of the olfactory mucosa in the nasal cavity. Recovery was monitored, and a lower percentage of the MT KO mice were able to smell 28 d after treatment; however, no significant difference was observed in the rate of cell proliferation in the basal layer of the olfactory epithelium between MT KO and wild-type mice. A lower concentration of ZG (33mM), equivalent to that found in homeopathic IN ZG preparations, also caused olfactory epithelial toxicity in mice. These studies suggest that the use of zinc in drug formulations intended for IN administration in humans must be carefully evaluated for their potential to cause olfactory functional deficits.
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Affiliation(s)
- Heidi Hsieh
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267-0056, United States
| | - Michael C Horwath
- Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267-0557, United States; Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, United States
| | - Mary Beth Genter
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267-0056, United States.
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Genter MB. Editor's Note. Int J Toxicol 2016; 35:375. [PMID: 27383452 DOI: 10.1177/1091581816657551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Hsieh H, Vignesh KS, Deepe GS, Choubey D, Shertzer HG, Genter MB. Mechanistic studies of the toxicity of zinc gluconate in the olfactory neuronal cell line Odora. Toxicol In Vitro 2016; 35:24-30. [PMID: 27179668 DOI: 10.1016/j.tiv.2016.05.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 05/06/2016] [Accepted: 05/09/2016] [Indexed: 11/15/2022]
Abstract
Zinc is both an essential and potentially toxic metal. It is widely believed that oral zinc supplementation can reduce the effects of the common cold; however, there is strong clinical evidence that intranasal (IN) zinc gluconate (ZG) gel treatment for this purpose causes anosmia, or the loss of the sense of smell, in humans. Using the rat olfactory neuron cell line, Odora, we investigated the molecular mechanism by which zinc exposure exerts its toxic effects on olfactory neurons. Following treatment of Odora cells with 100 and 200μM ZG for 0-24h, RNA-seq and in silico analyses revealed up-regulation of pathways associated with zinc metal response, oxidative stress, and ATP production. We observed that Odora cells recovered from zinc-induced oxidative stress, but ATP depletion persisted with longer exposure to ZG. ZG exposure increased levels of NLRP3 and IL-1β protein levels in a time-dependent manner, suggesting that zinc exposure may cause an inflammasome-mediated cell death, pyroptosis, in olfactory neurons.
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Affiliation(s)
- Heidi Hsieh
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267-0056, United States
| | | | - George S Deepe
- Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267-0557, United States; Veterans Affairs Medical Center, Cincinnati, OH 45220, United States
| | - Divaker Choubey
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267-0056, United States
| | - Howard G Shertzer
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267-0056, United States
| | - Mary Beth Genter
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267-0056, United States.
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Abstract
With the increasing use of and interest in nanoparticles in medicine and technology, the tissue and cell-specific localization of the particles are important considerations when the nanomaterials find their way into biological systems. This brief communication shows the utility of autometallography in determining the location of metal deposition at the light microscopic level. Although primarily focusing on studies of the toxicity and deposition of silver nanoparticles, use of autometallography to localize zinc and other metals at the tissue and subcellular localization is also recognized.
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Affiliation(s)
- David L Miller
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH, USA
| | - Il Je Yu
- Institute of Nanoproduct Safety Research, Hoseo University, Asan, Korea
| | - Mary Beth Genter
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH, USA
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Davenport LL, Hsieh H, Eppert BL, Carreira VS, Krishan M, Ingle T, Howard PC, Williams MT, Vorhees CV, Genter MB. Systemic and behavioral effects of intranasal administration of silver nanoparticles. Neurotoxicol Teratol 2015; 51:68-76. [PMID: 26340819 PMCID: PMC4692053 DOI: 10.1016/j.ntt.2015.08.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 07/17/2015] [Accepted: 08/25/2015] [Indexed: 12/13/2022]
Abstract
Use of silver nanoparticles (AgNPs) for their antimicrobial properties is widespread. Much of the previous work on the toxicity of AgNPs has been conducted in vitro or following oral or intravenous administration in vivo. Intranasal (IN) instillation of AgNPs mimics inhalation exposure and allows further exploration of the toxicity of these particles via respiratory tract exposure. The present study involved 1) single-dose exposures to assess tissue distribution and toxicity and 2) repeated exposures to assess behavioral effects of IN AgNP exposure (nominally uncoated 25 nm AgNP). AgNP deposition was localized in the liver, gut-associated lymphoid tissue, and brain. Decrease cellularity in spleen follicles was observed in treated mice, along with changes in cell number and populations in the spleen. The splenic GSH:GSSG ratio was also reduced following AgNP exposure. Expression of the oxidative stress-responsive gene Hmox1 was elevated in the hippocampus, but not cortex of treated mice, as was the level of HMOX1 protein. Mice receiving 7 days of IN exposure to 50 mg/kg AgNPs exhibited similar learning- and memory-related behaviors to control mice, except that treated mice spent significantly less time in the target quadrant of the Morris Water Maze during the acquisition phase probe trial. These findings indicate systemic distribution and toxicity following IN administration of AgNPs.
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Affiliation(s)
- Laurie L Davenport
- Department of Environmental Health, University of Cincinnati, 160 Panzeca Way, Cincinnati, OH 45267 USA
| | - Heidi Hsieh
- Department of Environmental Health, University of Cincinnati, 160 Panzeca Way, Cincinnati, OH 45267 USA
| | - Bryan L Eppert
- Department of Environmental Health, University of Cincinnati, 160 Panzeca Way, Cincinnati, OH 45267 USA
| | - Vinicius S Carreira
- Department of Environmental Health, University of Cincinnati, 160 Panzeca Way, Cincinnati, OH 45267 USA
| | - Mansi Krishan
- Department of Environmental Health, University of Cincinnati, 160 Panzeca Way, Cincinnati, OH 45267 USA
| | - Taylor Ingle
- NCTR/ORA Nanotechnology Core Facility, 3900 NCTR Rd., Jefferson, AR 72079, USA
| | - Paul C Howard
- NCTR/ORA Nanotechnology Core Facility, 3900 NCTR Rd., Jefferson, AR 72079, USA
| | - Michael T Williams
- Division of Child Neurology (MLC 7044), Cincinnati Children's Research Foundation, 3333 Burnet Ave., Cincinnati, OH 45229 USA
| | - Charles V Vorhees
- Division of Child Neurology (MLC 7044), Cincinnati Children's Research Foundation, 3333 Burnet Ave., Cincinnati, OH 45229 USA
| | - Mary Beth Genter
- Department of Environmental Health, University of Cincinnati, 160 Panzeca Way, Cincinnati, OH 45267 USA.
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Genter MB, Brock WJ, Mattes WB. Scientific conduct... and misconduct. Toxicol Sci 2015; 144:3-4. [PMID: 25901331 DOI: 10.1093/toxsci/kfu284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Genter MB. Book Review: Dictionary of Toxicology. Int J Toxicol 2015. [DOI: 10.1177/1091581815577351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Mary Beth Genter
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH, USA
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Genter MB. Book Review: Toxicologic Pathology: Nonclinical Safety Assessment. Int J Toxicol 2014. [DOI: 10.1177/1091581814557599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Mary Beth Genter
- PhD, DABT, Department of Environmental Health, University of Cincinnati, Cincinnati, OH, USA
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Abstract
Zinc (Zn) has long been touted as a panacea for common cold. Recently, there has been some controversy over whether an intranasal (IN) zinc gluconate gel, purported to fight colds, causes anosmia, or loss of the sense of smell, in humans. Previous evidence has shown that IN zinc sulfate (ZnSO4) solutions can cause anosmia in humans as well as significant damage to the olfactory epithelium in rodents. Using an in vitro olfactory neuron model (the rat Odora cell line), we tested the hypothesis that Zn toxicity was caused by inhibition of the hydrogen voltage-gated channel 1(HVCN1), leading to acidosis and apoptotic cell death. Following studies to characterize the toxicity of zinc gluconate and ZnSO4, Odora cells were grown on coverslips and loaded with 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester to measure intracellular pH in the presence and absence of Zn salts. While we found that HVCN1 is not functional in Odora cells, we found that olfactory neurons in vitro maintain their intracellular pH through a sodium/proton exchanger, specifically the sodium proton antiporter 1. ZnSO4, at nontoxic levels, had no impact on intracellular pH after acute exposure or after 24 h of incubation with the cells. In conclusion, Zn toxicity is not mediated through an acidification of intracellular pH in olfactory neurons in vitro.
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Affiliation(s)
- H Hsieh
- Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - H Amlal
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - M B Genter
- Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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Krishan M, Gudelsky GA, Desai PB, Genter MB. Manipulation of olfactory tight junctions using papaverine to enhance intranasal delivery of gemcitabine to the brain. Drug Deliv 2014; 21:8-16. [PMID: 24116937 PMCID: PMC4750388 DOI: 10.3109/10717544.2013.840017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
CONTEXT Delivery of drugs from the nasal cavity to the brain is becoming more widely accepted, due to the non-invasive nature of this route and the ability to circumvent the blood brain barrier (BBB). OBJECTIVE Because of similarities in the proteins comprising the olfactory epithelial tight junction (TJ) proteins and those of the BBB, we sought to determine whether papaverine (PV), which is known to reversibly enhance BBB permeability, could increase the delivery of intranasally administered gemcitabine to the central nervous system in rats. Experimental methods: Included intranasal administration of gemcitabine, fluorescein isothiocyanate-dextran beads and PV, histopathology, immunostaining, RT-PCR, western blot analysis, immunofluorescence localization, spectrofluorometric analysis, in vivo brain microdialysis, HPLC analysis and in vitro gemcitabine recovery. RESULTS AND DISCUSSION PV transiently decreased the levels and altered immunolocalization of the TJ protein phosphorylated-occludin in the olfactory epithelium, while causing an approximately four-fold increase in gemcitabine concentration reaching the brain. The enhanced delivery was not accompanied by nasal epithelial damage or toxicity to distant organs. CONCLUSIONS The ability to transiently and safely increase drug delivery from the nose to the brain represents a non-invasive way to improve treatment of patients with brain disorders.
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Affiliation(s)
- Mansi Krishan
- Department of Environmental Health, Center for Environmental Genetics, University of Cincinnati, Cincinnati, OH, USA
| | - Gary A. Gudelsky
- College of Pharmacy, University of Cincinnati, Cincinnati, OH, USA
| | - Pankaj B. Desai
- College of Pharmacy, University of Cincinnati, Cincinnati, OH, USA
| | - Mary Beth Genter
- Department of Environmental Health, Center for Environmental Genetics, University of Cincinnati, Cincinnati, OH, USA
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Krishan M, Gudelsky G, Desai P, Genter MB. Enhanced intranasal delivery of gemcitabine to the central nervous system. Toxicol Lett 2013. [DOI: 10.1016/j.toxlet.2013.05.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Shertzer HG, Krishan M, Genter MB. Dietary whey protein stimulates mitochondrial activity and decreases oxidative stress in mouse female brain. Neurosci Lett 2013; 548:159-64. [PMID: 23748211 DOI: 10.1016/j.neulet.2013.05.061] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 05/03/2013] [Accepted: 05/29/2013] [Indexed: 11/17/2022]
Abstract
In humans and experimental animals, protein-enriched diets are beneficial for weight management, muscle development, managing early stage insulin resistance and overall health. Previous studies have shown that in mice consuming a high fat diet, whey protein isolate (WPI) reduced hepatosteatosis and insulin resistance due in part to an increase in basal metabolic rate. In the current study, we examined the ability of WPI to increase energy metabolism in mouse brain. Female C57BL/6J mice were fed a normal AIN-93M diet for 12 weeks, with (WPI group) or without (Control group) 100g WPI/L drinking water. In WPI mice compared to controls, the oxidative stress biomarkers malondialdehyde and 4-hydroxyalkenals were 40% lower in brain homogenates, and the production of hydrogen peroxide and superoxide were 25-35% less in brain mitochondria. Brain mitochondria from WPI mice remained coupled, and exhibited higher rates of respiration with proportionately greater levels of cytochromes a+a3 and c+c1. These results suggested that WPI treatment increased the number or improved the function of brain mitochondria. qRT-PCR revealed that the gene encoding a master regulator of mitochondrial activity and biogenesis, Pgc-1alpha (peroxisome proliferator-activated receptor-gamma coactivator-1alpha) was elevated 2.2-fold, as were the PGC-1alpha downstream genes, Tfam (mitochondrial transcription factor A), Gabpa/Nrf-2a (GA-binding protein alpha/nuclear respiratory factor-2a), and Cox-6a1 (cytochrome oxidase-6a1). Each of these genes had twice the levels of transcript in brain tissue from WPI mice, relative to controls. There was no change in the expression of the housekeeping gene B2mg (beta-2 microglobulin). We conclude that dietary whey protein decreases oxidative stress and increases mitochondrial activity in mouse brain. Dietary supplementation with WPI may be a useful clinical intervention to treat conditions associated with oxidative stress or diminished mitochondrial activity in the brain.
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Affiliation(s)
- Howard G Shertzer
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati Medical Center, P.O. Box 670056, Cincinnati, OH 45267, USA.
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Dong H, Shertzer HG, Genter MB, Gonzalez FJ, Vasiliou V, Jefcoate C, Nebert DW. Mitochondrial targeting of mouse NQO1 and CYP1B1 proteins. Biochem Biophys Res Commun 2013; 435:727-32. [PMID: 23692925 DOI: 10.1016/j.bbrc.2013.05.051] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 05/12/2013] [Indexed: 10/26/2022]
Abstract
Four dioxin-inducible enzymes--NAD(P)H: quinone oxidoreductase-1 (NQO1) and three cytochromes P450 (CYP1A1, CYP1A2 & CYP1B1)--are implicated in both detoxication and metabolic activation of various endobiotics and xenobiotics. NQO1 is generally regarded as a cytosolic enzyme; whereas CYP1 proteins are located primarily in endoplasmic reticulum (ER), CYP1A1 and CYP1A2 proteins are also targeted to mitochondria. This lab has generated Cyp1a1(mc/mc) and Cyp1a1(mtt/mtt) knock-in mouse lines in which CYP1A1 protein is targeted exclusively to ER (microsomes) and mitochondria, respectively. Comparing dioxin-treated Cyp1(+/+) wild-type, Cyp1a1(mc/mc), Cyp1a1(mtt/mtt), and Cyp1a1(-/-), Cyp1b1(-/-) and Nqo1(-/-) knockout mice, in the present study we show that [a] NQO1 protein locates to cytosol, ER and mitochondria, [b] CYP1B1 protein (similar to CYP1A1 and CYP1A2 proteins) traffics to mitochondria as well as ER, and [c] NQO1 and CYP1B1 targeting to mitochondrial or ER membranes is independent of CYP1A1 presence in that membrane.
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Affiliation(s)
- Hongbin Dong
- Department of Environmental Health and Center for Environmental Genetics, University Cincinnati Medical Center, Cincinnati, OH 45267-0056, USA
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Genter MB. Editor’s Note. Int J Toxicol 2013; 32:99. [DOI: 10.1177/1091581813483101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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