Olfactory epithelium, which detects and transmits odor signals, is critical for the function of olfactory system. Olfactory epithelium is able to recover spontaneously after injury under normal circumstances, but this ability is dampened in certain diseases or senility, which causes olfactory dysfunction. The olfactory epithelium consists of basal cells, sustentacular cells and olfactory sensory neurons. In order to develop an olfactory epithelial organoid containing multiple olfactory cell types in vitro, we used three-dimensional culture model and small molecules screening. This organoid system consists of horizontal basal-like cells, globose basal-like cells, sustentacular-like cells and olfactory sensory neurons-like cells. Through statistical analysis of clone diameter, immunofluorescence staining and qPCR detection of the expression level of related marker genes. We identified a series of growth factors and small molecule compounds that affected the proliferation, composition and gene expression of the organoids. CHIR-99021, an activator of Wnt signaling pathway, increased the colony formation and proliferation rate of olfactory epithelial organoids and the expression level of marker genes of olfactory sensory neurons-like cells. In addition, each factor in the culture system increased the proportion of c-Kit-positive globose basal-like cell colonies in organoids. Moreover, EGF and vitamin C were both beneficial to the expression of horizontal basal-like cell marker genes in organoids. The established olfactory epithelial organoid system mimicked the process of olfactory epithelial stem cells differentiating into various olfactory epithelial cell types, thus providing a research model for studying olfactory epithelial tissue regeneration, the pathological mechanism of olfactory dysfunction and drug screening for olfactory dysfunction treatment.
Humans ; Olfactory Mucosa/metabolism* ; Epithelial Cells ; Organoids/metabolism* ; Olfaction Disorders/metabolism*

Objective: To investigate the effects of dopamine on olfactory function and inflammatory injury of olfactory bulb in mice with allergic rhinitis (AR). Methods: AR mouse model was established by using ovalbumin (OVA), and the mice were divided into two groups: olfactory dysfunction (OD) group and without OD group through buried food pellet test (BFPT). The OD mice were randomly divided into 2 groups, and OVA combined with dopamine (3, 6, 9 and 12 days, respectively) or OVA combined with an equal amount of PBS (the same treatment time) was administered nasally. The olfactory function of mice was evaluated by BFPT. The number of eosinophils and goblet cells in the nasal mucosa were detected by HE and PAS staining. Western blotting, immunohistochemistry or immunofluorescence were used to detect the expression of olfactory marker protein (OMP) in olfactory epithelium, the important rate-limiting enzyme tyrosine hydroxylase (TH) of dopamine, and the marker proteins glial fibrillary acidic protein (GFAP) and CD11b of glial cell in the olfactory bulb. TUNEL staining was used to detect the damage of the olfactory bulb. SPSS 26.0 software was used for statistical analysis. Results: AR mice with OD had AR pathological characteristics. Compared with AR mice without OD, the expression of OMP in olfactory epithelium of AR mice with OD was reduced (F=26.09, P<0.05), the expression of GFAP and CD11b in the olfactory bulb was increased (F value was 38.95 and 71.71, respectively, both P<0.05), and the expression of TH in the olfactory bulb was decreased (F=77.00, P<0.05). Nasal administration of dopamine could shorten the time of food globule detection in mice to a certain extent, down-regulate the expression of GFAP and CD11b in the olfactory bulb (F value was 6.55 and 46.11, respectively, both P<0.05), and reduce the number of apoptotic cells in the olfactory bulb (F=25.64, P<0.05). But dopamine had no significant effect on the number of eosinophils and goblet cells in nasal mucosa (F value was 36.26 and 19.38, respectively, both P>0.05), and had no significant effect on the expression of OMP in the olfactory epithelium (F=55.27, P>0.05). Conclusion: Dopamine can improve olfactory function in mice with AR to a certain extent, possibly because of inhibiting the activation of glial cells in olfactory bulb and reducing the apoptotic injury of olfactory bulb cells.
Animals ; Disease Models, Animal ; Dopamine ; Humans ; Mice ; Mice, Inbred BALB C ; Nasal Mucosa/metabolism* ; Olfactory Bulb/pathology* ; Ovalbumin ; Rhinitis, Allergic/metabolism*

PURPOSE: We evaluated the severity of olfactory disturbance (OD) in the murine model of allergic rhinitis (AR) and local allergic rhinitis (LAR) in mice. We also investigated the therapeutic effect of an intranasal steroid on OD. METHODS: Forty BALB/c mice were divided into 5 groups (n = 8 for each). The control group was sensitized intraperitoneally (i.p.) and challenged intranasally (i.n.) with saline. Mice in the AR group got i.p. and i.n. ovalbumin (OVA) administration for AR induction. The LAR group was challenged i.n. with 1% OVA for inducing local nasal allergic inflammation, without inducing the systemic allergy. The OD group got an i.p. methimazole administration (75 mg/kg) to induce total destruction of olfactory mucosa. Mice in the intranasal budesonide group received i.n. budesonide (12.8 μg per time, 30 minutes after the i.n. OVA challenge) while using OVA to cause systemic allergies. We conducted a buried-food pellet test to functionally assess the degree of OD in each group by measuring the time taken until finding hidden food. We evaluated the damage to olfactory epithelium using histopathologic evaluation and compared the degree of olfactory marker protein (OMP) expression in olfactory epithelium using immunofluorescent staining. RESULTS: Mice of the AR (81.3 ± 19.8 seconds) and LAR groups (66.2 ± 12.7 seconds) spent significantly more time to detect the pellets than the control group (35.6 ± 12.2 seconds, P < 0.01). After treatment, the intranasal budesonide group exhibited significantly better results (35.8 ± 11.9 seconds) compared with the AR and LAR groups (P < 0.01). The AR and LAR groups showed considerable olfactory epithelial damage and suppression of OMP expression compared with the control group. In the intranasal budesonide group, the olfactory lesions and OMP expression had improved substantially. CONCLUSIONS: OD may be caused by olfactory epithelial damage and suppression of OMP expression in nasal allergic inflammation and could be reversed using an intranasal steroid.
Animals ; Budesonide ; Hypersensitivity ; Inflammation ; Methimazole ; Mice ; Olfaction Disorders ; Olfactory Marker Protein ; Olfactory Mucosa ; Ovalbumin ; Ovum ; Quality of Life ; Rhinitis, Allergic ; Steroids

The olfactory epithelium is capable of structural and functional recovery after injury through neurogenesis. Neurogenesis occurs via stem cells in the olfactory epithelium. Horizontal basal cells and globose basal cells in the basal layer of the epithelium have the characteristics of stem cells and progenitor cells of olfactory neurons. In order for the horizontal basal cells and globose basal cells to differentiate into olfactory neurons, distinct transcriptional factors are required at each stage. These transcription factors inhibit or synergize with each other or cells at each differentiation stage, regulating olfactory neurogenesis. Recently, the regulation of neurogenesis and development through epigenetic controls that change gene expression without changing the gene sequence have been studied. Studies of olfactory epithelium have helped to elucidate complex neurological systems including spinal cord and brain. In particular, features of neurogenesis will lead to medical advances in the treatment of central nervous diseases, which until this time have been considered impossible.
Brain ; Epigenomics ; Epithelium ; Gene Expression ; Neurogenesis ; Neurons ; Olfactory Mucosa ; Spinal Cord ; Stem Cells ; Transcription Factors

Olfactory receptors (ORs) in mammals are generally considered to function as chemosensors in the olfactory organs of animals. They are membrane proteins that traverse the cytoplasmic membrane seven times and work generally by coupling to heterotrimeric G protein. The OR is a G protein–coupled receptor that binds the guanine nucleotide-binding G(αolf) subunit and the Gβγ dimer to recognize a wide spectrum of organic compounds in accordance with its cognate ligand. Mammalian ORs were originally identified from the olfactory epithelium of rat. However, it has been recently reported that the expression of ORs is not limited to the olfactory organ. In recent decades, they have been found to be expressed in diverse organs or tissues and even tumors in mammals. In this review, the expression and expected function of olfactory receptors that exist throughout an organism's system are discussed.
Animals ; Cell Membrane ; Ectopic Gene Expression ; GTP-Binding Proteins ; Guanine ; Mammals* ; Membrane Proteins ; Olfactory Mucosa ; Rats

To explore whether hypoxic condition could promote the olfactory mucosa mesenchymal stem cells (OM-MSCs) to differentiate into neurons with the olfactory ensheathing cells (OECs) supernatant and the potential mechanisms.
 Methods: The OM-MSCs and OECs were isolated and cultured, and they were identified by flow cytometry and immunofluorescence. The OM-MSCs were divided into three groups: a 3%O2+ HIF-1α inhibitors (lificiguat: YC-1) + OECs supernatant group (Group A) , a 3%O2 + OECs supernatant group (Group B) and a 21%O2 + OECs supernatant group (Control group). The neurons, which were differentiated from OM-MSCs, were assessed by immunofluorescence test. The mRNA and protein expression of hypoxia-inducible factor-1α (HIF-1α), βIII-tubulin and glial fibrillary acidic portein (GFAP) were detected by quantitative polymerase chain reaction (Q-PCR) and Western blot. The potassium channels were analyzed by patch clamp.
 Results: The neurons differentiated from OM-MSCs expressed the most amount of βIII-tubulin, and the result of Q-PCR showed that HIF-1α expression in the Group B was significantly higher than that in the other groups (all P<0.05). Western blot result showed that the βIII-tubulin protein expression was significantly higher and GFAP protein expression was obviously decreased in the Group B (both P<0.05). The patch clamp test confirmed that the potassium channels in the neurons were activated.
 Conclusion: Hypoxic condition can significantly increase the neuronal differentiation of OM-MSCs by the OECs supernatant and decrease the production of neuroglia cells, which is associated with the activation of HIF-1 signal pathway.
Blotting, Western ; Cell Differentiation ; physiology ; Cells, Cultured ; Culture Media, Conditioned ; chemistry ; pharmacology ; Flow Cytometry ; Glial Fibrillary Acidic Protein ; metabolism ; Hypoxia ; physiopathology ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism ; Indazoles ; pharmacology ; Mesenchymal Stem Cells ; physiology ; Neurogenesis ; physiology ; Neuroglia ; metabolism ; physiology ; Neurons ; physiology ; Olfactory Mucosa ; Potassium Channels ; Signal Transduction ; Tubulin ; metabolism

Olfactory dysfunction is one of the most debilitating problem in chronic rhinosinusitis (CRS) patients, and exact mechanism underlying sinusitis induced olfactory dysfunction was not fully understood. In vivo manipulation for olfactory epithelium and fresh specimen for histopathological analysis are essential for research, but it is nearly impossible to do in human due to inaccessibility of olfactory epithelium and risk for complication. For this reason, several animal models using toxic materials, such as 3-methylindole or bromomethane, have been suggested for mimicking olfactory epithelial damage in CRS, but none of them could truly imitate the event which happens in real patient. Inducible olfactory inflammation (IOI) mouse is a transgenic mouse model selectively producing tumor necrosis factor-alpha (TNF-alpha) in sustentacular cell of olfactory epithelium. The production of TNF-alpha can be actively initiated by giving food containing doxycycline to IOI mouse, and inflammation is stopped in the absence of doxycycline. Both toxicity model and transgenic model have their own advantages and disadvantages, therefore appropriate model should be selected for optimal results.
Animals ; Animals, Genetically Modified ; Doxycycline ; Humans ; Inflammation ; Mice* ; Mice, Transgenic ; Models, Animal ; Olfactory Mucosa ; Sinusitis* ; Skatole ; Smell ; Tumor Necrosis Factor-alpha

OBJECTIVE: To observe the biological characteristics of the human olfactory mucosa mesenchymal stem cells (hOM-MSCs). METHODS: The hOM-MSCs were isolated, cultured and identified in vitro. Scanning electron microscope and transmission electron microscope were used to observe the ultrastructure of hOMMSCs. Th e cells were induced towards adipocyte, osteocyte, neural stem cells, neural-like-cells in vitro. RESULTS: The hOM-MSCs were mainly in spindle shape, arranged with radial colony. The hOMMSCs expressed CD73 and CD90 but no CD34 and CD45. Th e short and thick microvilli processes were seen at the surface of hOM-MSCs by scanning electron microscope, and 2 different cellular morphology of hOM-MSCs were seen under transmission electron microscope. Moreover, the hOMMSCs could be differentiated into adipocyte, osteocyte, neural stem cells and neural cells. CONCLUSION The hOM-MSCs possess general biological characteristics of MSCs and display multiple differentiation functions. They can be served as ideal seed cells in tissue-engineering for injury repair.
Cell Differentiation ; Cells, Cultured ; Humans ; Mesenchymal Stem Cells ; cytology ; ultrastructure ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Olfactory Mucosa ; cytology

OBJECTIVE: To investigate the bionomics of the olfactory ensheathing cells (OECs) of human olfactory mucosa. METHOD: To separate and cultivate the OECs of human and rat olfactory mucosa. To observe the cell growth, cell grouping and cell migration in vitro of the two types of OECs. RESULT: Successfully separated and cultivated the OECs of human and rat olfactory mucosa. OECs of the human and rat olfactory mucosa had the similar cell growth, cell grouping and cell migration ability in vitro. CONCLUSION OECs of the human and rat olfactory mucosa have the similar bionomics in vitro, as a result, OECs of the human olfactory mucosa could be a reliable source of cell transplant for nerve injury.
Animals ; Cell Culture Techniques ; Cell Movement ; Cells, Cultured ; Humans ; Olfactory Mucosa ; cytology ; Rats

Over the last decades, piles of data have been accumulated to understand the olfactory sensation in every aspect, ranging from the intracellular signaling to cognitive perception. This review focuses on the ion conduction through multiple ion channels expressed in olfactory sensory neurons (OSNs) to describe how odorant binding to olfactory receptors is transduced into an electrical signal. Olfactory signal transduction and the generation of the depolarizing receptor current occur in the cilia, where the unique extraciliary environment of the nasal mucosa assists in the neuronal activation. Upon contacting with odorants, OSNs dissociate G protein-coupled receptors, initiating a signal transduction pathway that leads to firing of action potential. This signaling pathway has a unique, two step organization: a cAMP-gated Ca2+ (CNG) channel and a Ca2+-activated Cl- channel (CACC), both of which contribute to signal amplification. This transduction mechanism requires an outward-directed driving force of Cl- established by active accumulation of Cl- within the lumen of the sensory cilia. To permit Cl- accumulation, OSNs avoid the expression of the 'Chloride Sensor: WNK3', that functions as the main Cl- exclusion co-transporter in neurons of the central nervous system (CNS). Cl- accumulation provides OSNs with the driving force for the depolarization, increasing the excitatory response magnitude. This is an interesting adaptation because of the fact that the olfactory cilia reside in the mucus, outside the body, where the concentrations of ions are not as well regulated as they are in normal interstitial compartments.
Action Potentials ; Central Nervous System ; Cilia ; Fires ; Ion Channels ; Ions ; Mucus ; Nasal Mucosa ; Neurons ; Odors ; Olfactory Receptor Neurons ; Sensation ; Sensory Receptor Cells* ; Signal Transduction ; Smell