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Guthrie OW. Noise Stress Abrogates Structure-Specific Endonucleases within the Mammalian Inner Ear. Int J Mol Sci 2024; 25:1749. [PMID: 38339024 PMCID: PMC10855171 DOI: 10.3390/ijms25031749] [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: 11/30/2023] [Revised: 01/19/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024] Open
Abstract
Nucleotide excision repair (NER) is a multistep biochemical process that maintains the integrity of the genome. Unlike other mechanisms that maintain genomic integrity, NER is distinguished by two irreversible nucleolytic events that are executed by the xeroderma pigmentosum group G (XPG) and xeroderma pigmentosum group F (XPF) structure-specific endonucleases. Beyond nucleolysis, XPG and XPF regulate the overall efficiency of NER through various protein-protein interactions. The current experiments evaluated whether an environmental stressor could negatively affect the expression of Xpg (Ercc5: excision repair cross-complementing 5) or Xpf (Ercc4: excision repair cross-complementing 4) in the mammalian cochlea. Ubiquitous background noise was used as an environmental stressor. Gene expression levels for Xpg and Xpf were quantified from the cochlear neurosensory epithelium after noise exposure. Further, nonlinear cochlear signal processing was investigated as a functional consequence of changes in endonuclease expression levels. Exposure to stressful background noise abrogated the expression of both Xpg and Xpf, and these effects were associated with pathological nonlinear signal processing from receptor cells within the mammalian inner ear. Given that exposure to environmental sounds (noise, music, etc.) is ubiquitous in daily life, sound-induced limitations to structure-specific endonucleases might represent an overlooked genomic threat.
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Affiliation(s)
- O'neil W Guthrie
- Cell & Molecular Pathology Laboratory, Department of Communication Sciences and Disorders, Northern Arizona University, Flagstaff, AZ 86011, USA
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Guthrie OW, Yang L. Oral intake of carboxy alkyl ester improves attention: A randomized double-blind cross-over placebo-controlled study. Hum Psychopharmacol 2023; 38:e2885. [PMID: 37915240 DOI: 10.1002/hup.2885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 10/24/2023] [Accepted: 10/25/2023] [Indexed: 11/03/2023]
Abstract
OBJECTIVE To test the null hypothesis that oral intake of the dietary supplement carboxy alkyl ester (CAE) would have no effect on attention as revealed by mean rapid visual information processing (RVIP) scores. METHODS In a randomized double-blind cross-over placebo-controlled trial, healthy participants (age 19-66 years) of both sexes were randomly assigned to consume 700 mg of CAE or 700 mg of placebo. They received baseline attention testing via the RVIP task. Then they consumed CAE or placebo followed by RVIP testing. Participants were then given a washout period where they did not consume CAE or placebo. Afterward, individuals who initially consumed CAE were given the placebo and those who initially consumed the placebo were given CAE. Finally, all participants were tested again via RVIP. RESULTS A priori statistical computation revealed that 30-day oral intake of CAE improved mean RVIP test scores (t = 2.4, p < .05) relative to that at baseline, which resulted in a rejection of the null hypothesis. CONCLUSIONS Daily oral intake of the CAE dietary supplement may boost attention and further research is now needed to confirm this observation.
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Affiliation(s)
- O'neil W Guthrie
- Cell & Molecular Pathology Laboratory, Communication Sciences and Disorders, Northern Arizona University, Flagstaff, Arizona, USA
| | - Li Yang
- Cell & Molecular Pathology Laboratory, Communication Sciences and Disorders, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
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Guthrie OW, Spankovich C. Emerging and established therapies for chemotherapy-induced ototoxicity. J Cancer Surviv 2023; 17:17-26. [PMID: 36637631 DOI: 10.1007/s11764-022-01317-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 12/07/2022] [Indexed: 01/14/2023]
Abstract
PURPOSE Ototoxicity is considered a dose-limiting side effect of some chemotherapies. Hearing loss, in particular, can have significant implications for the quality of life for cancer survivors. Here, we review therapeutic approaches to mitigating ototoxicity related to chemotherapy. METHODS Literature review. CONCLUSIONS Numerous otoprotection strategies are undergoing active investigation. However, numerous challenges exist to confer adequate protection while retaining the anti-cancer efficacy of the chemotherapy. IMPLICATIONS FOR CANCER SURVIVORS Ototoxicity can have significant implications for cancer survivors, notably those receiving cisplatin. Clinical translation of multiple otoprotection approaches will aid in limiting these consequences.
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Affiliation(s)
- O'neil W Guthrie
- Cell & Molecular Pathology Laboratory, Communication Sciences and Disorders, Northern Arizona University, Flagstaff, AZ, USA
| | - Christopher Spankovich
- Department of Otolaryngology Head and Neck Surgery, University of Mississippi Medical Center, Jackson, MS, USA.
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Guthrie OW, Bhatt IS. Nondeterministic nature of sensorineural outcomes following noise trauma. Biol Open 2021; 10:272549. [PMID: 34668520 PMCID: PMC8543023 DOI: 10.1242/bio.058696] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 09/08/2021] [Indexed: 11/20/2022] Open
Abstract
Over 1.1 billion individuals are at risk for noise induced hearing loss yet there is no accepted therapy. A long history of research has demonstrated that excessive noise exposure will kill outer hair cells (OHCs). Such observations have fueled the notion that dead OHCs underlie hearing loss. Therefore, previous and current therapeutic approaches are based on preventing the loss of OHCs. However, the relationship between OHC loss and hearing loss is at best a modest correlation. This suggests that in addition to the death of OHCs, other mechanisms may regulate the type and degree of hearing loss. In the current study, we tested the hypothesis that permanent noise-induced-hearing loss is consequent to additional mechanisms beyond the noise dose and the death of OHCs. Hooded male rats were randomly divided into noise and control groups. Morphological and physiological assessments were conducted on both groups. The combined results suggest that beyond OHC loss, the surviving cochlear elements shape sensorineural outcomes, which can be nondeterministic. These findings provide the basis for individualized ototherapeutics that manipulate surviving cellular elements in order to bias cochlear function towards normal hearing even in the presence of dead OHCs. Summary: The current findings provide the basis for individualized ototherapeutics that manipulate surviving cellular elements in order to bias cochlear function towards normal hearing even in the presence of dead cells.
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Affiliation(s)
- O'neil W Guthrie
- Department of Communication Sciences & Disorders, Northern Arizona University, Flagstaff, AZ 86011, USA.,Cell & Molecular Pathology Laboratory, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Ishan S Bhatt
- Audiogenomics Research Laboratory, Department of Communication Sciences and Disorders, The University of Iowa, Iowa City, IA 52242, USA
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Guthrie OW. Functional consequences of inducible genetic elements from the p53 SOS response in a mammalian organ system. Exp Cell Res 2017; 359:50-61. [DOI: 10.1016/j.yexcr.2017.08.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 08/02/2017] [Accepted: 08/05/2017] [Indexed: 10/19/2022]
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Guthrie OW. Noise Stress Induces an Epidermal Growth Factor Receptor/Xeroderma Pigmentosum-A Response in the Auditory Nerve. J Histochem Cytochem 2017; 65:173-184. [PMID: 28056182 DOI: 10.1369/0022155416683661] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
In response to toxic stressors, cancer cells defend themselves by mobilizing one or more epidermal growth factor receptor (EGFR) cascades that employ xeroderma pigmentosum-A (XPA) to repair damaged genes. Recent experiments discovered that neurons within the auditory nerve exhibit basal levels of EGFR+XPA co-expression. This finding implied that auditory neurons in particular or neurons in general have the capacity to mobilize an EGFR+XPA defense. Therefore, the current study tested the hypothesis that noise stress would alter the expression pattern of EGFR/XPA within the auditory nerve. Design-based stereology was used to quantify the proportion of neurons that expressed EGFR, XPA, and EGFR+XPA with and without noise stress. The results revealed an intricate neuronal response that is suggestive of alterations to both co-expression and individual expression of EGFR and XPA. In both the apical and middle cochlear coils, the noise stress depleted EGFR+XPA expression. Furthermore, there was a reduction in the proportion of neurons that expressed XPA-alone in the middle coils. However, the noise stress caused a significant increase in the proportion of neurons that expressed EGFR-alone in the middle coils. The basal cochlear coils failed to mobilize a significant response to the noise stress. These results suggest that EGFR and XPA might be part of the molecular defense repertoire of the auditory nerve.
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Affiliation(s)
- O'neil W Guthrie
- Cell & Molecular Pathology Laboratory, Department of Communication Sciences and Disorders, Northern Arizona University, Flagstaff, Arizona (OWG).,Research Service-151, Loma Linda Veterans Affairs Medical Center, Loma Linda, California (OWG).,Department of Otolaryngology and Head & Neck Surgery, School of Medicine, Loma Linda University Medical Center, Loma Linda, California (OWG)
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Guthrie OW. Noise Induced DNA Damage Within the Auditory Nerve. Anat Rec (Hoboken) 2016; 300:520-526. [DOI: 10.1002/ar.23494] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/21/2016] [Accepted: 07/09/2016] [Indexed: 11/06/2022]
Affiliation(s)
- O'neil W. Guthrie
- Cell and Molecular Pathology Laboratory, Department of Communication Sciences and Disorders; Northern Arizona University; Flagstaff Arizona
- Research Service-151 Loma Linda Veterans Affairs Medical Center; Loma Linda California
- Department of Otolaryngology and Head & Neck Surgery, School of Medicine; Loma Linda University Medical Center; Loma Linda California
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Guthrie OW. Localization and distribution of neurons that co-express xeroderma pigmentosum-A and epidermal growth factor receptor within Rosenthal's canal. Acta Histochem 2015; 117:688-95. [PMID: 26493720 DOI: 10.1016/j.acthis.2015.10.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 10/06/2015] [Accepted: 10/10/2015] [Indexed: 12/12/2022]
Abstract
Xeroderma pigmentosum-A (XPA) is a C4-type zinc-finger scaffolding protein that regulates the removal of bulky-helix distorting DNA damage products from the genome. Phosphorylation of serine residues within the XPA protein is associated with improved protection of genomic DNA and cell death resistance. Therefore, kinase signaling is one important mechanism for regulating the protective function of XPA. Previous experiments have shown that spiral ganglion neurons (SGNs) may mobilize XPA as a general stress response to chemical and physical ototoxicants. Therapeutic optimization of XPA via kinase signaling could serve as a means to improve DNA repair capacity within neurons following injury. The kinase signaling activity of the epidermal growth factor receptor (EGFR) has been shown in tumor cell lines to increase the repair of DNA damage products that are primarily repaired by XPA. Such observations suggest that EGFR may regulate the protective function of XPA. However, it is not known whether SGNs in particular or neurons in general could co-express XPA and EGFR. In the current study gene and protein expression of XPA and EGFR were determined from cochlear homogenates. Immunofluorescence assays were then employed to localize neurons expressing both EGFR and XPA within the ganglion. This work was then confirmed with double-immunohistochemistry. Rosenthal's canal served as the reference space in these experiments and design-based stereology was employed in first-order stereology quantification of immunoreactive neurons. The results confirmed that a population of SGNs that constitutively express XPA may also express the EGFR. These results provide the basis for future experiments designed to therapeutically manipulate the EGFR in order to regulate XPA activity and restore gene function in neurons following DNA damage.
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Guthrie OW, Wong BA, McInturf SM, Reboulet JE, Ortiz PA, Mattie DR. Inhalation of Hydrocarbon Jet Fuel Suppress Central Auditory Nervous System Function. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2015; 78:1154-1169. [PMID: 26408153 DOI: 10.1080/15287394.2015.1070389] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
More than 800 million L/d of hydrocarbon fuels is used to power cars, boats, and jet airplanes. The weekly consumption of these fuels necessarily puts the public at risk for repeated inhalation exposure. Recent studies showed that exposure to hydrocarbon jet fuel produces lethality in presynaptic sensory cells, leading to hearing loss, especially in the presence of noise. However, the effects of hydrocarbon jet fuel on the central auditory nervous system (CANS) have not received much attention. It is important to investigate the effects of hydrocarbons on the CANS in order to complete current knowledge regarding the ototoxic profile of such exposures. The objective of the current study was to determine whether inhalation exposure to hydrocarbon jet fuel might affect the functions of the CANS. Male Fischer 344 rats were randomly divided into four groups (control, noise, fuel, and fuel + noise). The structural and functional integrity of presynaptic sensory cells was determined in each group. Neurotransmission in both peripheral and central auditory pathways was simultaneously evaluated in order to identify and differentiate between peripheral and central dysfunctions. There were no detectable effects on pre- and postsynaptic peripheral functions. However, the responsiveness of the brain was significantly depressed and neural transmission time was markedly delayed. The development of CANS dysfunctions in the general public and the military due to cumulative exposure to hydrocarbon fuels may represent a significant but currently unrecognized public health issue.
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Affiliation(s)
- O'neil W Guthrie
- a Cell & Molecular Pathology Laboratory, Department of Communication Sciences and Disorders , Northern Arizona University , Flagstaff , Arizona , USA
- b Research Service, Loma Linda Veterans Affairs Medical Center , Loma Linda , California , USA
- c Department of Otolaryngology and Head & Neck Surgery , School of Medicine, Loma Linda University Medical Center , Loma Linda , California , USA
| | - Brian A Wong
- d Naval Medical Research Unit-Dayton , Wright-Patterson Air Force Base , Ohio , USA
| | - Shawn M McInturf
- d Naval Medical Research Unit-Dayton , Wright-Patterson Air Force Base , Ohio , USA
| | - James E Reboulet
- d Naval Medical Research Unit-Dayton , Wright-Patterson Air Force Base , Ohio , USA
| | - Pedro A Ortiz
- d Naval Medical Research Unit-Dayton , Wright-Patterson Air Force Base , Ohio , USA
| | - David R Mattie
- e Molecular Bioeffects Branch, Bioeffects Division, Human Effectiveness Directorate , Air Force Research Laboratory, Wright Patterson Air Force Base , Ohio , USA
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Poljšak B, Fink R. The protective role of antioxidants in the defence against ROS/RNS-mediated environmental pollution. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2014; 2014:671539. [PMID: 25140198 PMCID: PMC4129148 DOI: 10.1155/2014/671539] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 06/03/2014] [Accepted: 06/17/2014] [Indexed: 02/07/2023]
Abstract
Overproduction of reactive oxygen and nitrogen species can result from exposure to environmental pollutants, such as ionising and nonionising radiation, ultraviolet radiation, elevated concentrations of ozone, nitrogen oxides, sulphur dioxide, cigarette smoke, asbestos, particulate matter, pesticides, dioxins and furans, polycyclic aromatic hydrocarbons, and many other compounds present in the environment. It appears that increased oxidative/nitrosative stress is often neglected mechanism by which environmental pollutants affect human health. Oxidation of and oxidative damage to cellular components and biomolecules have been suggested to be involved in the aetiology of several chronic diseases, including cancer, cardiovascular disease, cataracts, age-related macular degeneration, and aging. Several studies have demonstrated that the human body can alleviate oxidative stress using exogenous antioxidants. However, not all dietary antioxidant supplements display protective effects, for example, β-carotene for lung cancer prevention in smokers or tocopherols for photooxidative stress. In this review, we explore the increases in oxidative stress caused by exposure to environmental pollutants and the protective effects of antioxidants.
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Affiliation(s)
- Borut Poljšak
- Faculty of Health Sciences, University of Ljubljana, Zdravstvena pot 5, SI-1000 Ljubljana, Slovenia
| | - Rok Fink
- Faculty of Health Sciences, University of Ljubljana, Zdravstvena pot 5, SI-1000 Ljubljana, Slovenia
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