Features of Remyelination after Transplantation of Olfactory Ensheathing Cells with Neurotrophic Factors into Spinal Cord Cysts.

This paper shows for the first time that co-transplantation of human olfactory ensheathing cells with neurotrophin-3 into spinal cord cysts is more effective for activation of remyelination than transplantation of cells with brain-derived neurotrophic factor and a combination of these two factors. The studied neurotrophic factors do not affect proliferation and migration of ensheathing cells in vitro. It can be concluded that the maximum improvement of motor function in rats receiving ensheathing cells with neurotrophin-3 is largely determined by activation of remyelination.

A conserved molecular logic for neurogenesis to gliogenesis switch in the cerebral cortex.

During development, neural stem cells in the cerebral cortex, also known as radial glial cells (RGCs), generate excitatory neurons, followed by production of cortical macroglia and inhibitory neurons that migrate to the olfactory bulb (OB). Understanding the mechanisms for this lineage switch is fundamental for unraveling how proper numbers of diverse neuronal and glial cell types are controlled. We and others recently showed that Sonic Hedgehog (Shh) signaling promotes the cortical RGC lineage switch to generate cortical oligodendrocytes and OB interneurons. During this process, cortical RGCs generate intermediate progenitor cells that express critical gliogenesis genes Ascl1, Egfr, and Olig2. The increased Ascl1 expression and appearance of Egfr+ and Olig2+ cortical progenitors are concurrent with the switch from excitatory neurogenesis to gliogenesis and OB interneuron neurogenesis in the cortex. While Shh signaling promotes Olig2 expression in the developing spinal cord, the exact mechanism for this transcriptional regulation is not known. Furthermore, the transcriptional regulation of Olig2 and Egfr has not been explored. Here, we show that in cortical progenitor cells, multiple regulatory programs, including Pax6 and Gli3, prevent precocious expression of Olig2, a gene essential for production of cortical oligodendrocytes and astrocytes. We identify multiple enhancers that control Olig2 expression in cortical progenitors and show that the mechanisms for regulating Olig2 expression are conserved between the mouse and human. Our study reveals evolutionarily conserved regulatory logic controlling the lineage switch of cortical neural stem cells.

Estrogens regulate early embryonic development of the olfactory sensory system via estrogen-responsive glia.

Estrogens are well-known to regulate development of sexual dimorphism of the brain; however, their role in embryonic brain development prior to sex-differentiation is unclear. Using estrogen biosensor zebrafish models, we found that estrogen activity in the embryonic brain occurs from early neurogenesis specifically in a type of glia in the olfactory bulb (OB), which we name estrogen-responsive olfactory bulb (EROB) cells. In response to estrogen, EROB cells overlay the outermost layer of the OB and interact tightly with olfactory sensory neurons at the olfactory glomeruli. Inhibiting estrogen activity using an estrogen receptor antagonist, ICI182,780 (ICI), and/or EROB cell ablation impedes olfactory glomerular development, including the topological organisation of olfactory glomeruli and inhibitory synaptogenesis in the OB. Furthermore, activation of estrogen signalling inhibits both intrinsic and olfaction-dependent neuronal activity in the OB, whereas ICI or EROB cell ablation results in the opposite effect on neuronal excitability. Altering the estrogen signalling disrupts olfaction-mediated behaviour in later larval stage. We propose that estrogens act on glia to regulate development of OB circuits, thereby modulating the local excitability in the OB and olfaction-mediated behaviour.

Function of Oncogene Mycn in Adult Neurogenesis and Oligodendrogenesis.

Human MYCN is an oncogene amplified in neuroblastoma and many other tumors. Both human MYCN and mouse Mycn genes are important in embryonic brain development, but their functions in adult healthy nerve system are completely unknown. Here, with Mycn-eGFP mice and quantitative RT-PCR, we found that Mycn was expressed in specific brain regions of young adult mice, including subventricular zone (SVZ), subgranular zone (SGZ), olfactory bulb (OB), subcallosal zone (SCZ), and corpus callosum (CC). With immunohistochemistry (IHC), we found that many Mycn-expressing cells expressed neuroblast marker doublecortin (DCX) and proliferation marker Ki67. With Dcx-creER and Mki67-creER mouse lines, we fate mapped Dcx-expressing neuroblasts and Mki67-expressing proliferation cells, along with deleting Mycn from these cells in adult mice. We found that knocking out Mycn from adult neuroblasts or proliferating cells significantly reduced cells in proliferation in SVZ, SGZ, OB, SCZ, and CC. We also demonstrated that the Mycn-deficient neuroblasts in SGZ matured quicker than wild-type neuroblasts, and that Mycn-deficient proliferating cells were more likely to survive in SVZ, SGZ, OB, SCZ, and CC compared to wild type. Thus, our results demonstrate that, in addition to causing tumors in the nervous system, oncogene Mycn has a crucial function in neurogenesis and oligodendrogenesis in adult healthy brain.

Comparison of the effects of two therapeutic strategies based on olfactory ensheathing cell transplantation and repetitive magnetic stimulation after spinal cord injury in female mice.

Spinal cord injury (SCI) is a debilitating condition, which leads to a permanent loss of functions below the injury site. The events which take place after SCI are characterized by cellular death, release of inhibitory factors, and inflammation. Many therapies have been studied to cure SCI, among them magnetic stimulation aims to reduce the secondary damages in particular by decreasing apoptosis, while, cellular transplantation promotes neuroregeneration by enhancing axonal regrowth. In the present study, we compared individually primary olfactory ensheathing cell (OEC) transplantation and repetitive trans-spinal magnetic stimulation (rTSMS) and then, we combined these two therapeutic approaches on tissue repair and functional recovery after SCI. To do so, SCIs were performed at Th10 level on female C57BL/6 mice, which were randomized into four groups: SCI, SCI + primary bOECs, SCI + STM, SCI + primary bulbar olfactory ensheathing cells (bOECs) + stimulation (STM). On these animals bioluminescence, immunohistological, and behavioral experiments were performed after SCI. Our results show that rTSMS has beneficial effect on the modulation of spinal scar by reducing fibrosis, demyelination, and microglial cell activation and by increasing the astroglial component of the scar, while, primary bOEC transplantation decreases microglial reactivity. At the opposite, locotronic experiments show that both treatments induce functional recovery. We did not observed any additional effect by combining the two therapeutic approaches. Taken together, the present study indicates that primary bOEC transplantation and rTSMS treatment act through different mechanisms after SCI to induce functional recovery. In our experimental paradigm, the combination of the two therapies does not induce any additional benefit.

Lipid Rafts from Olfactory Ensheathing Cells: Molecular Composition and Possible Roles.

Olfactory ensheathing cells (OECs) are specialized glial cells of the olfactory system, believed to play a role in the continuous production of olfactory neurons and ensheathment of their axons. Although OECs are used in therapeutic applications, little is known about the cellular mechanisms underlying their migratory behavior. Recently, we showed that OEC migration is sensitive to ganglioside blockage through A2B5 and Jones antibody in OEC culture. Gangliosides are common components of lipid rafts, where they participate in several cellular mechanisms, including cell migration. Here, we characterized OEC lipid rafts, analyzing the presence of specific proteins and gangliosides that are commonly expressed in motile neural cells, such as young neurons, oligodendrocyte progenitors, and glioma cells. Our results showed that lipid rafts isolated from OECs were enriched in cholesterol, sphingolipids, phosphatidylcholine, caveolin-1, flotillin-1, gangliosides GM1 and 9-O-acetyl GD3, A2B5-recognized gangliosides, CNPase, α-actinin, and ß1-integrin. Analysis of the actin cytoskeleton of OECs revealed stress fibers, membrane spikes, ruffled membranes and lamellipodia during cell migration, as well as the distribution of α-actinin in membrane projections. This is the first description of α-actinin and flotillin-1 in lipid rafts isolated from OECs and suggests that, together with ß1-integrin and gangliosides, membrane lipid rafts play a role during OEC migration. This study provides new information on the molecular composition of OEC membrane microdomains that can impact on our understanding of the role of OEC lipid rafts under physiological and pathological conditions of the nervous system, including inflammation, hypoxia, aging, neurodegenerative diseases, head trauma, brain tumor, and infection.

Frontline Science: Conversion of neutrophils into atypical Ly6G+ SiglecF+ immune cells with neurosupportive potential in olfactory neuroepithelium.

Neutrophils are generally considered as short-lived, homogenous, and terminally differentiated phagocytes that play crucial roles in conquering infection, although they occasionally cause severe collateral tissue damage or chronic inflammation. Recent reports have indicated that neutrophils also play a protective role in inflammation resolution and tissue repair. However, how terminally differentiated neutrophils have diverse functions remains unclear. Here, we show that neutrophils undergo conversion into Ly6G+ SiglecF+ double-positive cells expressing neurosupportive genes in the olfactory neuroepithelium (OE) under an inflammatory state. Through comprehensive flow cytometric analysis of murine nose, we identified Ly6G+ SiglecF+ double-positive cells that reside only in the OE under steady-state conditions. Double-positive cells were neutrophil-derived cells and increased by more than 10-fold during inflammation or tissue injury. We found that neutrophils infiltrate into the nose to express proinflammatory genes in the acute phase of inflammatory state, and they gradually change their surface markers and gene expression, expressing some neurogenesis-related genes in addition to inflammation related genes in the later phase. As the OE is known to have exceptionally high regeneration capacity as a nervous system, these findings suggest that neutrophils have the potential to contribute neurogenesis after conversion in peripheral nervous tissues, providing a challenge on a classic view of neutrophils as terminally differentiated leukocytes.

Severe Zinc Deficiency Causes the Loss and Apoptosis of Olfactory Ensheathing Cells (OECs) and Olfactory Deficit.

Dietary zinc deficiency may lead to olfactory deficits, whose mechanism remains largely elusive. Olfactory ensheathing cells (OECs), a type of glial cells that support the function and neurogenesis in the olfactory bulb (OB), may play a pivotal role in the maintenance of the olfactory system. In the present study, we established a rat model of dietary zinc deficiency and found that severe zinc deficiency, but not marginal zinc deficiency, caused significantly reduced food intake, growth retardation, and apparent olfactory deficit in growing rats. We showed that severe zinc deficiency resulted in the loss of OECs in the olfactory nerve layer (ONL) of the olfactory bulb. In addition, we revealed that the number of TUNEL-positive cells increased markedly in the region, suggesting an involvement of apoptotic cell death in zinc deficiency-induced loss of OECs. Moreover, we found that treatment with zinc chelator N,N,N'N',-tetrakis (2-pyridylmethyl)ethylenediamine (TPEN) triggered the apoptosis of in vitro-cultured primary OECs. The apoptosis of OECs was correlated with significantly elevated expression of p53. Importantly, TUNEL and CCK-8 assays both demonstrated that treatment with p53 antagonist pifithrin-α (PFT-α) markedly attenuated TPEN-induced OEC apoptosis. These findings implicated that p53-triggered apoptosis of OECs might play an integral role in zinc deficiency-induced olfactory malfunction.

Rabbit vomeronasal organ-derivered cells have mesenchymal profile and neuronal commitment / Las células derivadas del órgano vomeronasal del conejo tienen perfil mesenquimatoso y compromiso neuronal

SUMMARY: The vomeronasal organ (VNO) is an accessory organ involved on the olfactory pathway, that detects pheromones and emits signals in order to modulate social and reproductive behavior. The VNO stem cells replace neurons throughout life. The aim of this study was to isolate and characterize cells derived from the vomeronasal organ from New Zealand rabbits. Five male rabbits with 120 days were used for cell isolation and culture. Results: VNO-derived cells presented labelling for proliferation (PCNA), undifferentiated profile (Nanog), neuronal (GFAP), mesenchymal stem cells (CD73, CD90 and CD105 and Stro-1). Also, presence of cytoskeletal (Vimentin, b-tubulin and CK-18) and absence of hematopoietic markers (CD34, CD117 and CD45) both by immunofluorescence and flow cytometry. By PCR it was possible to verify the expression of some undifferentiated profile (Oct-4), neuronal (Nestin) and mesenchymal (CD73, CD105 and Vimentin) genes. Functionally, VNO-derived cells differentiate in vitro into adipocytes, osteocytes and chondrocytes, and presented no tumorigenic potential when injected to Balb/c nu/nu mice. In conclusion, the rabbit VNO-derived cells have a profile that could be supportive to VNO olfactory/neuroreceptor epithelium by delivering factors to epithelial turnover or even by differentiation into epithelial cells to replacement of commissural epithelium.

RESUMEN: El órgano vomeronasal (OVN) es un órgano accesorio de la vía olfatoria, que detecta feromonas y emite señales que afectan la modulación del comportamiento social y reproductivo. Las células madre OVN reemplazan las neuronas durante toda la vida. El objetivo de este estudio fue aislar y caracterizar células derivadas del órgano vomeronasal de conejos raza Nueva Zelanda. Para el aislamiento y el cultivo celular se utilizaron cinco conejos machos con una edad de 120 días. Las células del OVN presentaron etiquetado para la proliferación (PCNA), un perfil indiferenciado (Nanog), neuronal (GFAP), células madre mesenquimales (CD73, CD90 y CD105 y Stro-1). Además, se ob- servó presencia de citoesqueleto (Vimentina, β-tubulina y CK-18) y ausencia de marcadores hematopoyéticos (CD34, CD117 y CD45) tanto por inmunofluorescencia como por citometría de flujo. Me- diante PCR fue posible verificar la expresión de algunos genes de perfil indiferenciado (Oct-4), neuronal (Nestin) y mesenquimatoso (CD73, CD105 y Vimentin). Las células derivadas del OVN se diferencian in vitro en adipocitos, osteocitos y condrocitos, y no presentan un potencial tumorigénico al ser infiltrados en ratones Balb / c nu / nu. En conclusión, las células derivadas de OVN de conejo tienen un perfil que podría ser compatible con el epitelio olfatorio / neurorreceptor de OVN transmitiendo factores al recambio epitelial o incluso mediante la diferenciación en células epiteliales para reemplazar el epitelio comisural.

Transplantation of activated olfactory ensheathing cells by curcumin strengthens regeneration and recovery of function after spinal cord injury in rats.

BACKGROUND AIMS: The pro-regeneration capabilities of olfactory ensheathing cells (OECs) remain controversial. However, little is known regarding whether the transplantation of activated OECs by curcumin (CCM) elicits neural regeneration and functional recovery after spinal cord injury (SCI) in rats, and the possible molecular mechanisms have never been investigated. METHODS: Primary OECs were treated with 1µM CCM for 1-3 days. Concomitantly, activated OECs were transplanted into the traumatic spinal cord of Sprague Dawley rats. One to 9 weeks after surgery, the assessment of behavior recovery was made using the Basso, Beattie and Bresnahan (BBB) locomotor scale; electrophysiology tests, such as somatosensory evoked potential (SEP) and motor evoked potential (MEP); and the cylinder test. Pathological study, including hematoxylin and eosin staining and immunofluorescence staining for neurofilaments (NFs), was conducted at 5 weeks post-surgery. In addition, activation profiles of OECs by CCM stimulus were assessed and levels of transglutaminase-2 (TG2) and phosphatidylserine receptor (PSR) in OECs stimulated by CCM were further determined. RESULTS: CCM remarkably enhanced OEC proliferation, improved cell viability and strengthened secretion of neurotrophins and anti-inflammatory factors. In addition, the levels of TG2 and PSR in CCM-treated OECs were significantly elevated. More importantly, beyond 1 week post-transplantation of CCM-treated OECs into lesioned spinal cord, BBB score and cylinder test score were significantly higher than that seen in the other three groups and a more postponed latent SEP and MEP period was noted. Furthermore, 5 weeks later, numerous, well-arranged NF-positive nerve fibers, lesions with less cavities and reduced levels of pro-inflammatory cytokines were found in activated OEC implantation groups. In addition, the number of NF-positive fibers was significantly improved and the number and area of both cavities and gliotic scars were remarkably decreased compared with the corresponding controls. CONCLUSIONS: Transplantation of OECs activated by CCM promotes neural regeneration and functional recovery following SCI, the underlying mechanisms of which are intimately associated with the elevated production of neurotrophic factors and anti-inflammatory factors in OECs stimulated by CCM as well as reduced pro-inflammatory cytokines from the post-contusion spinal cord. In addition, OECs activated by CCM were mediated through TG2 and PSR.

Cortical Neural Stem Cell Lineage Progression Is Regulated by Extrinsic Signaling Molecule Sonic Hedgehog.

Neural stem cells (NSCs) in the prenatal neocortex progressively generate different subtypes of glutamatergic projection neurons. Following that, NSCs have a major switch in their progenitor properties and produce γ-aminobutyric acid (GABAergic) interneurons for the olfactory bulb (OB), cortical oligodendrocytes, and astrocytes. Herein, we provide evidence for the molecular mechanism that underlies this switch in the state of neocortical NSCs. We show that, at around E16.5, mouse neocortical NSCs start to generate GSX2-expressing (GSX2+) intermediate progenitor cells (IPCs). In vivo lineage-tracing study revealed that GSX2+ IPC population gives rise not only to OB interneurons but also to cortical oligodendrocytes and astrocytes, suggesting that they are a tri-potential population. We demonstrated that Sonic hedgehog signaling is both necessary and sufficient for the generation of GSX2+ IPCs by reducing GLI3R protein levels. Using single-cell RNA sequencing, we identify the transcriptional profile of GSX2+ IPCs and the process of the lineage switch of cortical NSCs.

Anosmin-1 activates vascular endothelial growth factor receptor and its related signaling pathway for olfactory bulb angiogenesis.

Anosmin-1 is a secreted glycoprotein encoded by the ANOS1 gene, and its loss of function causes Kallmann syndrome (KS), which is characterized by anosmia and hypogonadism due to olfactory bulb (OB) dysfunction. However, the physiological function of anosmin-1 remains to be elucidated. In KS, disordered angiogenesis is observed in OB, resulting in its hypoplasia. In this study, we examined the involvement of anosmin-1 in angiogenic processes. Anosmin-1 was detected on the vessel-like structure in OB of chick embryos, and promoted the outgrowth of vascular sprouts as shown by assays of OB tissue culture. Cell migration, proliferation, and tube formation of endothelial cells were induced by treatment with anosmin-1 as well as vascular endothelial growth factor-A (VEGF-A), and further enhanced by treatment with both of them. We newly identified that anosmin-1 activated VEGF receptor-2 (VEGFR2) by binding directly to it, and its downstream signaling molecules, phospholipase Cγ1 (PLCγ1) and protein kinase C (PKC). These results suggest that anosmin-1 plays a key role in the angiogenesis of developing OB through the VEGFR2-PLCγ1-PKC axis by enhancing the VEGF function.

Transplantation of microencapsulated olfactory ensheathing cells inhibits the P2X2 receptor over-expressionmediated neuropathic pain in the L4-5 spinal cord segment.

OBJECTIVES: The purpose of this study was to determine the effect of microencapsulated olfactory ensheathing cells (MC-OECs) transplantation on neuropathic pain (NPP) caused by sciatic nerve injury in rats, and its relationship with the expression levels of P2X2 receptor (P2X2R) in the L4-5 spinal cord segment. METHODS: Olfactory bulb tissue was removed from a healthy Sprague-Dawley (SD) rat for culturing olfactory ensheathing cells (OECs). Forty-eight SD rats were randomly divided into four groups (12 per group): the sham, chronic constriction injury (CCI), olfactory ensheathing cells (OECs), and MC-OECs groups. On days 7 and 14 after surgery, the mechanical withdrawal thresholds (MWT) were measured by using behavioral method. The expression levels of P2X2R in the L4-5 spinal cord segment were detected by in situ hybridization and Western blotting. RESULTS: On days 7 and 14 post-surgical, the MWT of rats from high to low were the sham, MC-OECs, OECs, and CCI groups, the MWT of rats in the MC-OECs groups were higher than that in OECs groups. The expression levels of P2X2R in the L4-5 spinal cord segment from high to low were the CCI, OECs, MC-OECs, and sham groups, the expression levels of P2X2R were lower than that in OECs groups. All differences between groups were statistically significant (p value <.05). CONCLUSIONS: OECs and MC-OECs transplantation can reduce the expression levels of P2X2R genes in the L4-5 spinal cord segment, and relieve NPP. The therapeutic efficacy of MC-OECs transplantation was better than the transplantation of OECs.

Neurogenic Niche Conversion Strategy Induces Migration and Functional Neuronal Differentiation of Neural Precursor Cells Following Brain Injury.

Glial scars formed after brain injuries provide permissive cues for endogenous neural precursor/stem cells (eNP/SCs) to undergo astrogenesis rather than neurogenesis. Following brain injury, eNP/SCs from the subventricular zone leave their niche, migrate to the injured cortex, and differentiate into reactive astrocytes that contribute to glial scar formation. In vivo neuronal reprogramming, directly converting non-neuronal cells such as reactive astrocytes or NG2 glia into neurons, has greatly improved brain injury repair strategies. However, reprogramming carries a high risk of future clinical applications such as tumorigenicity, involving virus. In this study, we constructed a neural matrix to alter the adverse niche at the injured cortex, enabling eNP/SCs to differentiate into functional neurons. We found that the neural matrix functioned as a "glial trap" that largely concentrated and limited reactive astrocytes to the core of the lesion area, thus altering the adverse niche. The eNP/SCs migrated toward the injured cortex and differentiated into functional neurons. In addition, regenerated neurites extended across the boundary of the injured cortex. Mice treated with the neural matrix demonstrated significant behavioral recovery. For the first time, we induced eNP/SC-derived functional neurons in the cortex after brain injury without the use of viruses, microRNAs, or small molecules. Our novel strategy of applying this "glial trap" to obtain functional neurons in the injured cortex may provide a safer and more natural therapeutic alternative to reprogramming in future clinical applications.

Microencapsulated olfactory ensheathing cell transplantation reduces P2X4 receptor overexpression and inhibits neuropathic pain in rats.

OBJECTIVES: The aim of this study was to determine the role of microencapsulated olfactory ensheathing cells (MC-OECs) transplantation in rats with sciatic nerve injury-induced neuropathic pain, and its relationship with P2X4 receptor expression in the L4-5 spinal cord segment. METHODS: Olfactory bulb tissues of healthy Sprague Dawley (SD) rats were collected to culture olfactory ensheathing cells (OECs) using differential attachment methods. Seventy-two healthy SD rats were randomly assigned to four groups: the sham, chronic constriction injury (CCI), OECs, and MC-OECs groups. Mechanical paw withdrawal thresholds were measured on days 7, 14 and 21 after surgery. The expression of P2X4 receptor genes in the L4-5 spinal cord segment was detected by in situ hybridization, western blotting and RT-PCR. RESULTS: On post-surgical days 7, 14 and 21. The mechanical paw withdrawal thresholds of rats from low to high were the CCI, OECs, MC-OECs and sham groups. The expression level of P2X4 receptor mRNA and protein from low to high were the sham, MC-OECs, OECs and CCI groups. Compared with the OECs group, the mechanical paw withdrawal thresholds of rats were increased, and the expression level of P2X4 receptor mRNA and protein were decreased in the MC-OECs group. In addition, the mechanical paw withdrawal thresholds of rats were higher and the expression level of P2X4 receptor were lower in the MC-OECs group on post-surgical days 21 than that on days 7 and 14. All differences between groups were statistically significant (P value < 0.05). CONCLUSIONS: OECs and MC-OECs transplantation can reduce the expression level of P2X4 receptor and relieve pain. The therapeutic efficacy was better in the MC-OECs group than in the OECs group. MC-OECs transplantation have the better effects of treatment with the increase of MC-OECs transplantation time.

High-definition spatial transcriptomics for in situ tissue profiling.

Spatial and molecular characteristics determine tissue function, yet high-resolution methods to capture both concurrently are lacking. Here, we developed high-definition spatial transcriptomics, which captures RNA from histological tissue sections on a dense, spatially barcoded bead array. Each experiment recovers several hundred thousand transcript-coupled spatial barcodes at 2-µm resolution, as demonstrated in mouse brain and primary breast cancer. This opens the way to high-resolution spatial analysis of cells and tissues.

Characteristics of olfactory ensheathing cells and microarray analysis in Tupaia belangeri (Wagner, 1841).

Tree shrews are most closely related to the primates and so possess a number of advantages in experimental studies; they have been used as an animal model in bacterial and virus infection, cancer, endocrine system disease, and certain nervous system diseases. Their olfactory ensheathing cells (OECs) are able to release several cytokines to promote neuronal survival, regeneration and remyelination. The present study used western blot analysis to identify antibody specificity in protein extracts from whole tree shrew brains to identify the specificity of p75 nerve growth factor receptor (NGFR) derived from rabbits (75 kDa). OECs were cultured and isolated, then stained and identified using the antibodies for p75NGFR. To investigate the capacity of OECs to express cytokines and growth factors, microarray technology was used, and the analysis revealed that OECs were able to express 9,821 genes. Of these genes, 44 genes were from the neurotrophic factor family, which may indicate their potential in transplantation in vivo. The present study considered the function of OECs as revealed by other studies, and may contribute to future research.

Differentiation of human olfactory system-derived stem cells into dopaminergic neuron-like cells: A comparison between olfactory bulb and mucosa as two sources of stem cells.

Cell transplantation has become a possible therapeutic approach in the treatment of neurodegenerative diseases of the nervous system by replacing lost cells. The current study aimed to make a comparison between the differentiation capacity of the olfactory bulb neural stem cells (OB-NSCs) and olfactory ectomesenchymal stem cells (OE-MSCs) into dopaminergic-like neurons under the inductive effect of transforming growth factor ß (TGF-ß). After culturing and treating with TGF-ß, the differentiation capacities of both types of stem cells into dopaminergic neuron-like cells were evaluated. Quantitative real-time polymerase chain reaction analysis 3 weeks after induction demonstrated that the mRNA expression of the dopaminergic activity markers tyrosine hydroxylase (TH), dopamine transporter (DAT), paired box gene 2 (PAX2), and PAX5 in the neuron-like cells derived from OB-NSCs was significantly higher than those derived from OE-MSCs. These findings were further supported by the immunocytochemistry staining showing that the expression of the tyrosine hydroxylase, DAT, PAX2, and paired like homeodomain 3 seemed to be slightly higher in OB-NSCs compared with OE-MSCs. Despite the lower differentiation capacity of OE-MSCs, other considerations such as a noninvasive and easier harvesting process, faster proliferation attributes, longer life span, autologous transplantability, and also the easier and inexpensive cultural process of the OE-MSCs, cumulatively make these cells the more appropriate alternative in the case of autologous transplantation during the treatment process of neurodegenerative disorders like Parkinson's disease.

Conductive hydrogel based on chitosan-aniline pentamer/gelatin/agarose significantly promoted motor neuron-like cells differentiation of human olfactory ecto-mesenchymal stem cells.

Developing a simple produces for efficient derivation of motor neurons (MNs) is essential for neural tissue engineering studies. Stem cells with high capacity for neural differentiation and scaffolds with the potential to promote motor neurons differentiation are promising candidates for neural tissue engineering. Recently, human olfactory ecto-mesenchymal stem cells (OE-MSCs), which are isolated easily from the olfactory mucosa, are considered a new hope for neuronal replacement due to their neural crest origin. Herein, we synthesized conducting hydrogels using different concentration of chitosan-g-aniline pentamer, gelatin, and agarose. The chemical structures, swelling and deswelling ratio, ionic conductivity and thermal properties of the hydrogel were characterized. Scaffolds with 10% chitosan-g-aniline pentamer/gelatin (S10) were chosen for further investigation and the potential of OE-MSCs as a new source for programming to motor neuron-like cells investigated on tissue culture plate (TCP) and conductive hydrogels. Cell differentiation was evaluated at the level of mRNA and protein synthesis and indicated that conductive hydrogels significantly increased the markers related to motor neurons including Hb-9, Islet-1 and ChAT compared to TCP. Taken together, the results suggest that OE-MSCs would be successfully differentiated into motor neuron-like cells on conductive hydrogels and would have a promising potential for treating motor neuron-related diseases.

Centrifugal Innervation of the Olfactory Bulb: A Reappraisal.

The inter-regional connectivity of sensory structures in the brain allows for the modulation of sensory processing in manners important for perception. In the olfactory system, odor representations in the olfactory bulb (OB) are modulated by feedback centrifugal innervation from several olfactory cortices, including the piriform cortex (PCX) and anterior olfactory nucleus (AON). Previous studies reported that an additional olfactory cortex, the olfactory tubercle (OT), also centrifugally innervates the OB and may even shape the activity of OB output neurons. In an attempt to identify the cell types of this centrifugal innervation, we performed retrograde tracing experiments in mice utilizing three unique strategies, including retrobeads, retrograde adeno-associated virus (AAV) driving a fluorescent reporter, and retrograde AAV driving Cre-expression in the Ai9-floxed transgenic reporter line. Our results replicated the standing literature and uncovered robustly labeled neurons in the ipsilateral PCX, AON, and numerous other structures known to innervate the OB. Surprisingly, consistent throughout all of our approaches, no labeled soma were observed in the OT. These findings indicate that the OT is unique among other olfactory cortices in that it does not innervate the OB, which refines our understanding of the centrifugal modulation of the OB.