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Cell and Tissue Research Jun 2021Detection and discrimination of odorants by the olfactory system plays a pivotal role in animal survival. Olfactory-based behaviors must be adapted to an ever-changing... (Review)
Review
Detection and discrimination of odorants by the olfactory system plays a pivotal role in animal survival. Olfactory-based behaviors must be adapted to an ever-changing environment. Part of these adaptations includes changes of odorant detection by olfactory sensory neurons localized in the olfactory epithelium. It is now well established that internal signals such as hormones, neurotransmitters, or paracrine signals directly affect the electric activity of olfactory neurons. Furthermore, recent data have shown that activity-dependent survival of olfactory neurons is important in the olfactory epithelium. Finally, as olfactory neurons are directly exposed to environmental toxicants and pathogens, the olfactory epithelium also interacts closely with the immune system leading to neuroimmune modulations. Here, we review how detection of odorants can be modulated in the vertebrate olfactory epithelium. We choose to focus on three cellular types of the olfactory epithelium (the olfactory sensory neuron, the sustentacular and microvillar cells) to present the diversity of modulation of the detection of odorant in the olfactory epithelium. We also present some of the growing literature on the importance of immune cells in the functioning of the olfactory epithelium, although their impact on odorant detection is only just beginning to be unravelled.
Topics: Animals; Humans; Olfactory Mucosa; Olfactory Receptor Neurons; Receptors, Odorant; Smell
PubMed: 33961125
DOI: 10.1007/s00441-021-03467-y -
International Journal of Molecular... Apr 2022Olfactory neurons connect the external environment and the brain, allowing the translocation of materials from the nasal cavity into the brain. The olfactory system is...
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.
Topics: Angiotensin-Converting Enzyme 2; Animals; COVID-19; Humans; Lysophospholipids; Mice; Olfactory Mucosa; Rats; Receptors, Lysophosphatidic Acid; Rodentia; SARS-CoV-2; Sphingosine; Sphingosine-1-Phosphate Receptors
PubMed: 35457160
DOI: 10.3390/ijms23084343 -
Cell and Tissue Research Jan 2021Olfactory perception is very individualized in humans and also in Drosophila. The process that individualize olfaction is adaptation that across multiple time scales and...
Olfactory perception is very individualized in humans and also in Drosophila. The process that individualize olfaction is adaptation that across multiple time scales and mechanisms shape perception and olfactory-guided behaviors. Olfactory adaptation occurs both in the central nervous system and in the periphery. Central adaptation occurs at the level of the circuits that process olfactory inputs from the periphery where it can integrate inputs from other senses, metabolic states, and stress. We will here focus on the periphery and how the fast, slow, and persistent (lifelong) adaptation mechanisms in the olfactory sensory neurons individualize the Drosophila olfactory system.
Topics: Animals; Drosophila; Odorants; Olfactory Receptor Neurons
PubMed: 33492517
DOI: 10.1007/s00441-020-03384-6 -
Communications Biology Sep 2022The olfactory nerve map describes the topographical neural connections between the olfactory epithelium in the nasal cavity and the olfactory bulb. Previous studies have...
The olfactory nerve map describes the topographical neural connections between the olfactory epithelium in the nasal cavity and the olfactory bulb. Previous studies have constructed the olfactory nerve maps of rodents using histological analyses or transgenic animal models to investigate olfactory nerve pathways. However, the human olfactory nerve map remains unknown. Here, we demonstrate that high-field magnetic resonance imaging and diffusion tensor tractography can be used to visualize olfactory sensory neurons while maintaining their three-dimensional structures. This technique allowed us to evaluate the olfactory sensory neuron projections from the nasal cavities to the olfactory bulbs and visualize the olfactory nerve maps of humans, marmosets and mice. The olfactory nerve maps revealed that the dorsal-ventral and medial-lateral axes were preserved between the olfactory epithelium and olfactory bulb in all three species. Further development of this technique might allow it to be used clinically to facilitate the diagnosis of olfactory dysfunction.
Topics: Animals; Humans; Magnetic Resonance Imaging; Mice; Olfactory Bulb; Olfactory Mucosa; Olfactory Nerve; Olfactory Pathways
PubMed: 36068329
DOI: 10.1038/s42003-022-03794-y -
Anatomical Record (Hoboken, N.J. : 2007) Mar 2022In a species of baleen whale, we identify olfactory epithelium that suggests a functional sense of smell and document the ontogeny of the surrounding olfactory anatomy....
In a species of baleen whale, we identify olfactory epithelium that suggests a functional sense of smell and document the ontogeny of the surrounding olfactory anatomy. Whales must surface to breathe, thereby providing an opportunity to detect airborne odorants. Although many toothed whales (odontocetes) lack olfactory anatomy, baleen whales (mysticetes) have retained theirs. Here, we investigate fetal and postnatal specimens of bowhead whales (Balaena mysticetus). Computed tomography (CT) reveals the presence of nasal passages and nasal chambers with simple ethmoturbinates through ontogeny. Additionally, we describe the dorsal nasal meatuses and olfactory bulb chambers. The cribriform plate has foramina that communicate with the nasal chambers. We show this anatomy within the context of the whole prenatal and postnatal skull. We document the tunnel for the ethmoidal nerve (ethmoid foramen) and the rostrolateral recess of the nasal chamber, which appears postnatally. Bilateral symmetry was apparent in the postnatal nasal chambers. No such symmetry was found prenatally, possibly due to tissue deformation. No nasal air sacs were found in fetal development. Olfactory epithelium, identified histologically, covers at least part of the ethmoturbinates. We identify olfactory epithelium using six explicit criteria of mammalian olfactory epithelium. Immunohistochemistry revealed the presence of olfactory marker protein (OMP), which is only found in mature olfactory sensory neurons. Although it seems that these neurons are scarce in bowhead whales compared to typical terrestrial mammals, our results suggest that bowhead whales have a functional sense of smell, which they may use to find prey.
Topics: Animals; Bowhead Whale; Ethmoid Bone; Nasal Cavity; Olfactory Mucosa; Skull
PubMed: 34117725
DOI: 10.1002/ar.24682 -
Journal of Veterinary Science Nov 2022The olfactory mucosa (OM) is crucial for odorant perception in the main olfactory system. The terminal carbohydrates of glycoconjugates influence chemoreception in the...
BACKGROUND
The olfactory mucosa (OM) is crucial for odorant perception in the main olfactory system. The terminal carbohydrates of glycoconjugates influence chemoreception in the olfactory epithelium (OE).
OBJECTIVES
The histological characteristics and glycoconjugate composition of the OM of Korean native cattle (Hanwoo, ) were examined to characterize their morphology and possible functions during postnatal development.
METHODS
The OM of neonate and adult Korean native cattle was evaluated using histological, immunohistochemical, and lectin histochemical methods.
RESULTS
Histologically, the OM in both neonates and adults consists of the olfactory epithelium and the lamina propria. Additionally, using periodic acid Schiff and Alcian blue (pH 2.5), the mucus specificity of the Bowman's gland duct and acini in the lamina propria was determined. Immunohistochemistry demonstrated that mature and immature olfactory sensory neurons of OEs express the olfactory marker protein and growth associated protein-43, respectively. Lectin histochemistry indicated that numerous glycoconjugates, including as N-acetylglucosamine, mannose, galactose, N-acetylgalactosamine, complex type N-glycan, and fucose groups, were expressed at varied levels in the different cell types in the OMs of neonates and adults at varying levels. According to our observations, the cattle possessed a well-developed olfactory system, and the expression patterns of glycoconjugates in neonatal and adult OMs varied considerably.
CONCLUSIONS
This is the first study to describe the morphological assessment of the OM of Korean native cattle with a focus on lectin histochemistry. The findings suggest that glycoconjugates may play a role in olfactory chemoreception, and that their labeling properties may be closely related to OM development and maturity.
Topics: Cattle; Animals; Lectins; Galactose; Olfactory Mucosa; Republic of Korea
PubMed: 36448434
DOI: 10.4142/jvs.22184 -
Cancer Cell Jun 2024The olfactory epithelium undergoes neuronal regeneration from basal stem cells and is susceptible to olfactory neuroblastoma (ONB), a rare tumor of unclear origins....
The olfactory epithelium undergoes neuronal regeneration from basal stem cells and is susceptible to olfactory neuroblastoma (ONB), a rare tumor of unclear origins. Employing alterations in Rb1/Trp53/Myc (RPM), we establish a genetically engineered mouse model of high-grade metastatic ONB exhibiting a NEUROD1 immature neuronal phenotype. We demonstrate that globose basal cells (GBCs) are a permissive cell of origin for ONB and that ONBs exhibit cell fate heterogeneity that mimics normal GBC developmental trajectories. ASCL1 loss in RPM ONB leads to emergence of non-neuronal histopathologies, including a POU2F3 microvillar-like state. Similar to small-cell lung cancer (SCLC), mouse and human ONBs exhibit mutually exclusive NEUROD1 and POU2F3-like states, an immune-cold tumor microenvironment, intratumoral cell fate heterogeneity comprising neuronal and non-neuronal lineages, and cell fate plasticity-evidenced by barcode-based lineage tracing and single-cell transcriptomics. Collectively, our findings highlight conserved similarities between ONB and neuroendocrine tumors with significant implications for ONB classification and treatment.
Topics: Animals; Mice; Small Cell Lung Carcinoma; Humans; Esthesioneuroblastoma, Olfactory; Cell Lineage; Lung Neoplasms; Basic Helix-Loop-Helix Transcription Factors; Tumor Microenvironment; Nose Neoplasms; Olfactory Mucosa; Disease Models, Animal; Tumor Suppressor Protein p53
PubMed: 38788720
DOI: 10.1016/j.ccell.2024.05.003 -
Scientific Reports Aug 2021The nasal mucosa (NM) contains olfactory mucosa which contributes to the detection of odorant molecules and the transmission of olfactory information to the brain. To... (Clinical Trial)
Clinical Trial
The nasal mucosa (NM) contains olfactory mucosa which contributes to the detection of odorant molecules and the transmission of olfactory information to the brain. To date, the lipid composition of the human NM has not been adequately characterized. Using gas chromatography, liquid chromatography coupled to mass spectrometry and thin layer chromatography, we analyzed the fatty acids and the phospholipid and ceramide molecular species in adult human nasal and blood biopsies. Saturated and polyunsaturated fatty acids (PUFAs) accounted for 45% and 29% of the nasal total fatty acids, respectively. Fatty acids of the n-6 family were predominant in the PUFA subgroup. Linoleic acid and arachidonic acid (AA) were incorporated in the main nasal phospholipid classes. Correlation analysis revealed that the nasal AA level might be positively associated with olfactory deficiency. In addition, a strong positive association between the AA levels in the NM and in plasma cholesteryl esters suggested that this blood fraction might be used as an indicator of the nasal AA level. The most abundant species of ceramides and their glycosylated derivatives detected in NM contained palmitic acid and long-chain fatty acids. Overall, this study provides new insight into lipid species that potentially contribute to the maintenance of NM homeostasis and demonstrates that circulating biomarkers might be used to predict nasal fatty acid content.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Fatty Acids; Female; Gas Chromatography-Mass Spectrometry; Humans; Lipidomics; Male; Middle Aged; Olfaction Disorders; Olfactory Mucosa
PubMed: 34408170
DOI: 10.1038/s41598-021-93817-1 -
ENeuro 2020Optical imaging of intracellular Ca influx as a correlate of neuronal excitation represents a standard technique for visualizing spatiotemporal activity of neuronal...
Optical imaging of intracellular Ca influx as a correlate of neuronal excitation represents a standard technique for visualizing spatiotemporal activity of neuronal networks. However, the information-processing properties of single neurons and neuronal circuits likewise involve inhibition of neuronal membrane potential. Here, we report spatially resolved optical imaging of odor-evoked inhibitory patterns in the olfactory circuitry of using a genetically encoded fluorescent Cl sensor. In combination with the excitatory component reflected by intracellular Ca dynamics, we present a comprehensive functional map of both odor-evoked neuronal activation and inhibition at different levels of olfactory processing. We demonstrate that odor-evoked inhibition carried by Cl influx is present both in sensory neurons and second-order projection neurons (PNs), and is characterized by stereotypic, odor-specific patterns. Cl-mediated inhibition features distinct dynamics in different neuronal populations. Our data support a dual role of inhibitory neurons in the olfactory system: global gain control across the neuronal circuitry and glomerulus-specific inhibition to enhance neuronal information processing.
Topics: Animals; Drosophila; Drosophila Proteins; Female; Membrane Potentials; Odorants; Olfactory Pathways; Olfactory Receptor Neurons; Receptors, Odorant; Smell
PubMed: 31888962
DOI: 10.1523/ENEURO.0213-19.2019 -
European Archives of... Jun 2023To report biomarkers present in the olfactory mucosa in chronic rhinosinusitis with nasal polyps (CRSwNP) in comparison with nasal polyps and to nasal mucosal tissues...
PURPOSE
To report biomarkers present in the olfactory mucosa in chronic rhinosinusitis with nasal polyps (CRSwNP) in comparison with nasal polyps and to nasal mucosal tissues from control patients. To evaluate the kinetics of smell over 6 months in patients who underwent Reboot surgery.
METHODS
Cohort study from May 2021 to May 2022. We collected samples of olfactory mucosa and nasal polyps from 16 CRSwNP patients and inferior turbinate samples from 20 control subjects. The study was not randomized for surgical and/or medical treatment. Samples were analyzed by Luminex and Unicap 100 to measure biomarkers of inflammation (IL1-β, IL4, IL5, IL6, IL17, CCL3, CCL4, G-CSF, SE-IgE, total IgE and ECP). 12 of the CRSwNP patients underwent Extended Sniffin'tests at timepoints 1-4 days pre-surgery, and 1, 3 and 6 months after Reboot surgery.
RESULTS
Type-2 markers were significantly elevated in OM and polyp tissue in CRSwNP (n = 16) vs. controls (n = 20), P < 0.05. TDI scores improved already 1 month (P < 0.05) after surgery and remained stable for 6 months. Type-2 inflammation in nasal polyps was associated with decreased sense of smell and taste before surgery, but improved after surgery (P = 0.048). Type-3 inflammation was present in the olfactory mucosa and was associated with a better sense of smell before surgery, but a smaller improvement of smell afterward.
CONCLUSIONS
Type-2 inflammation is present in the olfactory mucosa in CRSwNP patients and is associated with smell loss. Reboot surgery, aiming to completely remove inflamed sinus mucosa, significantly improves the smell in this group of patients.
Topics: Humans; Smell; Nasal Polyps; Prospective Studies; Olfaction Disorders; Cohort Studies; Rhinitis; Sinusitis; Inflammation; Chronic Disease; Immunoglobulin E
PubMed: 36571613
DOI: 10.1007/s00405-022-07813-w