CD34+ stromal cells/telocytes and their role in mouse lung development: Light microscopy, immunofluorescence, ultrastructural and scanning electron microscopy evidence.

Telocytes (TCs), a novel type of mesenchymal or interstitial cell with specific, very long and thin cellular prolongations, have been found in various mammalian organs and have potential biological functions. However, their existence during lung development is poorly understood. This study aimed to investigate the existence, morphological features, and role of CD34+ SCs/TCs in mouse lungs from foetal to postnatal life using primary cell culture, double immunofluorescence, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The immunofluorescence double staining profiles revealed positive expression of CD34 and PDGFR-α, Sca-1 or VEGFR-3, and the expression of these markers differed among the age groups during lung development. Intriguingly, in the E18.5 stage of development, along with the CD34+ SCs/TCs, haematopoietic stem cells and angiogenic factors were also significantly increased in number compared with those in the E14.5, E16.5, P0 and P7. Subsequently, TEM confirmed that CD34+ SCs/TCs consisted of a small cell body with long telopodes (Tps) that projected from the cytoplasm. Tps consisted of alternating thin and thick segments known as podomers and podoms. TCs contain abundant endoplasmic reticulum, mitochondria and secretory vesicles and establish close connections with neighbouring cells. Furthermore, SEM revealed characteristic features, including triangular, oval, spherical, or fusiform cell bodies with extensive cellular prolongations, depending on the number of Tps. Our findings provide evidence for the existence of CD34+ SCs/TCs, which contribute to vasculogenesis, the formation of the air‒blood barrier, tissue organization during lung development and homoeostasis.

Rational Regulation of Optimal Oxygen Vacancy Concentrations on VO2 for Superior Aqueous Zinc-Ion Battery Cathodes.

VO2 with its special tunnel structure and high theoretical capacity is an ideal candidate for cathode materials for aqueous zinc-ion batteries (ZIBs). However, the slow kinetics and structural instability due to the strong electrostatic interactions between the host structure of VO2 and Zn2+ hinder its application. Defect engineering is a well-recognized strategy for improving the intrinsic ion-electron dynamics and structural stability of this material. However, the preparation of oxygen vacancies poses significant difficulties, and it is challenging to control their concentration effectively. Excessive or insufficient vacancy concentration can have a negative effect on the cathode material. Herein, we propose electrode materials with controlled oxygen vacancies prepared in situ on carbon nanofibers (CNF) by a simple, one-step hydrothermal process (Ov-VO2@CNF). This method can balance the adsorption energy and migration energy barrier easily, and we maximized the adsorption energy of Zn2+ while minimizing the adsorption energy barrier. Notably, the Ov2-VO2@CNF electrode delivered a high specific capacity (over 450 mAh g-1 at 0.1 A g-1) and excellent cycle stability (318 mAh g-1 at 5 A g-1 capacity after 2000 cycles with a capacity retention of 85%). This rational design of precisely regulated defect engineering provides a way to obtain advanced electrode materials with excellent comprehensive properties.

Realization of Enhanced Interfacial Lithium-Ion Transfer in Composite Polymer Electrolytes via Grafting Oligo-PEG Molecular Brushes on Silica-Coated Nanofibers for All-Solid-State Lithium Metal Batteries.

Polyether-based polymer electrolytes are attractive but still challenging for high-energy-density solid-state lithium metal batteries due to their limited Li-ion conductivity at room temperature. Herein, an oligomeric polyethylene glycol methyl ether methacrylate (PEGMEM)-modified silica-coated polyimide fibrous scaffold (PINF@PEGMEM-SiO2) was introduced in polyethylene glycol dimethyl ether (PEGDME) to enhance the Li-ion transportation at room temperature. PINF@PEGMEM-SiO2 was developed to build a continuous and interconnected interface for continuous Li-ion transportation in bulk. The carbonyl groups (C═O) of PEGMEM on SiO2 can promote the dissociation of lithium salts and enhance the migration of free Li ions at the interface. The same -C-C-O- unit contained in both PEGMEM and PEGDME ensures the compatibility of PEGMEM at the interface and PEGDME in the bulk. The prepared PEGDME-based polymer electrolyte exhibits a high ionic conductivity of 1.14 × 10-4 S cm-1 at 25 °C and an improved Li-ion transference number of 0.41. Furthermore, LiFePO4/Li and LiNi0.8Co0.1Mn0.1O2/Li cells with excellent cyclability and rate capability at ambient temperature are obtained.

Human Menstrual Blood-Derived Endometrial Stem Cells Promote Functional Recovery by Improving the Inflammatory Microenvironment in a Mouse Spinal Cord Injury Model.

Spinal cord injury (SCI) is a traumatic injury of the central nervous system. Because neurons are damaged and difficult to regenerate after SCI, its repair remains challenging. However, recent research on stem cell therapy have favored its use after SCI. In this study, based on the establishment of a mouse SCI model, human menstrual blood-derived endometrial stem cells (MenSCs) were intrathecally injected to explore the role and molecular mechanism of MenSCs in SCI. MenSCs were transplanted following SCI in the animal model, and behavioral evaluations showed that MenSC transplantation improved functional recovery. Therefore, samples were collected after 7 days, and transcriptome sequencing was performed. Gene Ontology (GO) enrichment analysis revealed that SCI is closely related to immune system processes. After transplantation of MenSCs, the immune response was significantly activated. In the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, MenSC transplantation was found to be closely related to Th1, Th2, and Th17 cell differentiation pathways. Neuronal damage and glial cell proliferation and activation in the different groups were detected by fluorescence immunohistochemistry and Western blotting 7 days after SCI. Simultaneously, the activation of different types of microglia was detected and the expression of pro-inflammatory and anti-inflammatory factors was quantitatively analyzed. The results showed that MenSC transplantation and sonic hedgehog (Shh)-induced MenSCs accelerated neuronal recovery at the injured site, inhibited the formation of glial cells and microglial activation at the injured site, inhibited the expression of inflammatory factors, and improved the inflammatory microenvironment to achieve functional recovery of SCI. This study provides an experimental basis for the study of the role and molecular mechanism of MenSCs in SCI repair, and a reference for the role of Shh-induced MenSCs in SCI repair.

CRISPR-Cas9-Mediated NPC1 Gene Deletion Enhances HEK 293 T Cell Adhesion by Regulating E-Cadherin.

NPC1 gene encodes a transmembrane glycoprotein on the late endosome/lysosomal membrane. Its mutation leads to a rare and aggravated autosomal recessive neurovisceral condition, termed Niemann-Pick disease type C1 (NPC1), which is characterized by progressive neurodegeneration, visceral symptoms, and premature death. To investigate the influence of NPC1 gene deletion on cell morphology, adhesion, proliferation, and apoptosis, CRISPR-Cas9 technology was used to knockout the NPC1 gene in HEK 293 T cells. Sanger sequencing, western blotting, and immunofluorescence were used to confirm successful NPC1 ablation. Filipin staining results indicated that deletion of NPC1 gene led to accumulation of unesterified cholesterol in HEK 293 T cells. Phalloidin staining results revealed cell aggregation, synapse shortening, nuclear enlargement, and cytoskeleton filamentous actin thinning in HEK 293 T cells with NPC1 gene mutation. Furthermore, NPC1 gene mutated HEK 293 T cell showed enhanced cell adhesion, inhibited cell proliferation, and increased cell apoptosis. In addition, NPC1 gene mutations significantly increased the protein expression levels of E-cadherin and γ-catenin and significantly decreased the protein expression levels of Wnt 3a, c-Myc, and cyclin D1. These results suggest that NPC1 may regulate cell adhesion by affecting the cadherin-catenin complex through E-cadherin, and that the classical Wnt signaling pathway may be inhibited by restricting ß-catenin from entering the nucleus to inhibit cell proliferation.

Cadherins and the pathogenesis of epilepsy.

Epilepsy is a nervous system disease caused by abnormal discharge of brain neurons, which is characterized by recurrent seizures. The factors that induce epilepsy include genetic and environmental factors. Genetic factors are important pathogenic factors of epilepsy, such as epilepsy caused by protocadherin-19 (PCDH-19) mutation, which is an X-linked genetic disease. It is more common in female heterozygotes, which are caused by mutations in the PCDH-19 gene. Epilepsy caused by environmental factors is mainly caused by brain injury, which is commonly caused by brain tumors, brain surgery, or trauma to the brain. In addition, the pathogenesis of epilepsy is closely related to abnormalities in some signaling pathways. The Wnt/ß-catenin signaling pathway is considered a new target for the treatment of epilepsy. This review summarizes these factors inducing epilepsy and the research hypotheses regarding the pathogenesis of epilepsy. The focus of this review centers on cadherins and the pathogenesis of epilepsy. We analyzed the pathogenesis of epilepsy induced by N-cadherin and PCDH-19 in the cadherin family members. Finally, we expect that in the future, new breakthroughs will be made in the study of the pathogenesis and mechanism of epilepsy at the cellular and molecular levels.

CRISPR-Cas9-Mediated Gene Therapy in Neurological Disorders.

Neurological disorders are primarily diseases with sophisticated etiology that are always refractory and recrudescent. The major obstruction to effective therapies for neurological disorders is the poor understanding of their pathogenic mechanisms. CRISPR-Cas9 technology, which allows precise and effective gene editing in almost any cell type and organism, is accelerating the pace of basic biological research. An increasing number of groups are focusing on uncovering the molecular mechanisms of neurological disorders and developing novel therapies using the CRISPR-Cas9 system. This review highlights the application of CRISPR-Cas9 technology in the treatment of neurological disorders, including Alzheimer's disease, amyotrophic lateral sclerosis and/or frontotemporal dementia, Duchenne muscular dystrophy, Dravet syndrome, epilepsy, Huntington's disease, and Parkinson's disease. Hopefully, it will improve our understanding of neurological disorders and give insights into future treatments for neurological disorders.

Deeply Cyclable and Ultrahigh-Rate Lithium Metal Anodes Enabled by Coaxial Nanochamber Heterojunction on Carbon Nanofibers.

Lithium metal anodes (LMAs) are the most promising candidates for high-energy-density batteries due to the high theoretical specific capacity and lowest potential. However, the practical application of LMAs is hampered by the short lifespan and unsatisfactory lithium utilization (<50%). An oxide-oxide heterojunction enhanced with nanochamber structure design is proposed to improve lithium utilization and cycling performance of LMA under ultrahigh rates. Typically, a MnO2 -ZnO heterojunction provides high binding energy for strong absorption of Li-ions and intimately bonded interfaces for fast transfer of electrons. Under the guidance of the smooth Li-ion migration and rapid electron flow, the Li metal can be restricted as thin layers within submicro scale in nanochambers with constrain boundary and stress dissipation, inhibiting the local agglomeration and blocking. Thus, the lithiophilic active sites can be effectively exposed to the Li-ions within submicro scale, improving the reversible conversion for high lithium utilization during long-term cycling. As such, the Li@MnZnO/CNF electrode achieves a high lithium utilization of 70% at a record-high current density of 50 mA cm-2 with areal capacity of 10 mAh cm-2 . This work offers an avenue to improve lithium utilization for long-lifespan LMAs working under high current densities and capacities.

Abnormal neuronal damage and inflammation in the hippocampus of kainic acid-induced epilepsy mice.

In this study, we established a mouse model of epilepsy and analysed abnormal neuronal damage and inflammation in the hippocampus of mice with kainic acid (KA)-induced epilepsy to provide the basis for the pathogenesis of epilepsy. C57 mice, aged 4 weeks, were injected intraperitoneally in the KA group with 20 mg/kg of KA and in the sham experimental group with normal saline. The whole brain and hippocampus of mice in the sham experimental group and KA epilepsy model group were collected on days 7, 14, 21 and 28 after injection. The difference in the protein expression in the hippocampus was detected using fluorescence immunohistochemistry. The hippocampal tissue was also collected and frozen to detect protein expression by western blot. The results of the haematoxylin and eosin (HE) and Nissl staining showed that the mouse model of temporal lobe epilepsy could be established by intraperitoneal injection of KA, and the success rate of the model was 53.8%. The expression of DCX-, ß-catenin-, GFAP- and Iba-1-labelled glial cells in the KA-induced epilepsy model group were higher than those in the sham group. The results of western blotting showed that the expression of DCX and ß-catenin in the KA-induced epilepsy model group was higher than that in the sham experimental group, while the expression of N-cadherin and Iba-1 on days 14 and 28 was significantly (P < .05) higher than that in the sham experimental group. In KA-induced epilepsy model group, the expression of Bcl-2 was decreased, while the expression of Bad and PUMA was increased.

A Fishing-Net-Like 3D Host for Robust and Ultrahigh-Rate Lithium Metal Anodes.

Constructing an architectural host is demonstrated to be an effective strategy for long-life lithium metal anodes (LMAs). Herein, an integrated 3D host for stable and ultrahigh-rate LMAs is developed by a binary highly conductive network of 2D reduced graphene oxide (rGO) and 1D carbon nanofibers (CNF) anchored with 0D ultrasmall MgZnO nanoparticles (MgZnO/CNF-rGO). A facile net-fishing strategy is proposed to combine the rGO nanosheets with free-standing CNF matrix as interconnected paths for fast electron transport. Notably, serving as Li nucleation sites, the superlithiophilic MgZnO nanoparticles are uniformly distributed and tightly contacted with the conductive matrix without agglomeration due to the rGO confinement. Such a delicate nanoscale combination guarantees the effective transportation and uniform deposition of Li-ions in the inner surface of the host. The symmetric cell of Li@MgZnO/CNF-rGO exhibits a long lifespan above 1450 cycles under an ultrahigh current density of 50 mA cm-2 with an areal capacity of 1.0 mAh cm-2 . Impressively, it also delivers a high reversible capacity of 10 mAh cm-2 at 50 mA cm-2 . This work offers an avenue to promise the prospect for practical LMAs working under high rates and capacities.

The role of Shh signalling pathway in central nervous system development and related diseases.

Sonic hedgehog (Shh) plays important roles in developmental of vertebrate animal central nervous system (CNS), and Gli is its downstream signal molecule. Shh signalling is essential for pattern formation, cell-fate specification, axon guidance, proliferation, survival and differentiation of neurons in CNS development. The abnormal signalling pathway of Shh leads to the occurrence of many nervous system diseases. The mechanism of Shh signalling is complex and remains incompletely understood. Nevertheless, studies have revealed that Shh signalling pathway is classified into canonical and non-canonical pathways. Here we review the role of the Shh signalling pathway and its impact in CNS development and related diseases. Specifically, we discuss the role of Shh in the spinal cord and brain development, cell differentiation and proliferation in CNS and related diseases such as brain tumour, Parkinson's diseases, epilepsy, autism, depression and traumatic brain injury. We also highlight future directions of research that could help to clarify the mechanisms and consequences of Shh signalling in the process of CNS development and related diseases. SIGNIFICANCE OF THE STUDY: This review summarized the role of Shh signalling pathway in CNS development and related diseases such as brain tumour, Parkinson's diseases, epilepsy, autism, depression and traumatic brain injury. It also presented the author's opinions on the future research direction of Shh signalling pathway.

A Triple-Gradient Host for Long Cycling Lithium Metal Anodes at Ultrahigh Current Density.

The viable Li metal anodes (LMAs) are still hampered by the safety concerns resulting from fast Li dendrite growth and huge volume expansion during cycling. Herein, carbon nanofiber matrix anchored with MgZnO nanoparticles (MgZnO/CNF) is developed as a flexible triple-gradient host for long cycling LMAs. The superlithiophilic MgZnO nanoparticles significantly increase the wettability of CNF for fast and homogeneous infusion with molten Li. The in-built potential and lithiophilic gradients constructed after an in situ lithiation of MgZnO and CNF enable nearly zero Li nucleation overpotential and homogeneous deposition of lithium at different scales. As such, the LMAs based on MgZnO/CNF achieve long cycling life and small overpotential even at a record-high current density of 50 mA cm-2 and a high areal capacity of 10 mAh cm-2 . A full cell paring with this designed LMA and LiFePO4 exhibits a capacity retention up to 82% after 600 cycles at a high rate of 5 C. A Li-ion capacitor also shows an impressive capacity retention of 84% at 5 A g-1 after 10 000 cycles. Such a Li@MgZnO/CNF anode is a promising candidate for Li-metal energy storage systems, especially working under ultrahigh current density.

Use of in vitro electroporation and slice culture for gene function analysis in the mouse embryonic spinal cord.

The spinal cord is an important part of the central nervous system (CNS). At present, the expression of the exogenous gene in the spinal cord of the embryonic mouse needs in utero spinal cord electroporation, but the success rate of this technique is very low. In this study, we have demonstrated the expression of an exogenous gene on one side of the spinal cord by combining two methods-in vitro electroporation of embryonic mouse spinal cord and organ spinal cord slices culture. We took 12-day embryonic mice, injected the green fluorescent protein (pCAGGS-GFP) plasmid into the spinal cord cavity in vitro, and then electroporated. The spinal cord was cut into 300-µm slices using a vibratory microtome. After cultured for 48 h, GFP-positive neurons were clearly observed on one side of the spinal cord, indicating that the exogenous gene was successfully transferred. The axon projection direction is basically unanimous from the inside to the lateral edge of the spinal cord. Compared to neurons in vivo, a single neuron in the culturing section has more complete neurites and is conducive to studying changes in the structure and behavior of individual neurons. Based on the above results, we have successfully established a convenient and efficient method for expressing the exogenous gene in the spinal cord of the mouse.

The Mechanism of Rap1 Regulates N-cadherin to Control Neuronal Migration.

Rap1 and N-cadherin regulate glia-independent translocation of cortical neurons. It remains unclear how Rap1 regulates N-cadherin-mediated neuronal migration. Here, we overexpressed Rap1gap in mouse brains (embryonic day 16) to inactivate Rap1, and observed that neurons did not migrate to the outer layer. We confirmed that Rap1 was involved in the regulation of late neurons in vivo. Rap1gap overexpression and Rap1 suppression in CHO cells decreased the expression of cytoskeletal proteins such as tubulin. Changes in the expression of cell morphology regulators, such as N-cadherin and ß-catenin, were also observed. Inhibition of N-cadherin in mouse brains prevented neuronal migration to the outer layer. The morphology of CHO cells was changed after overexpression of Rap1gap. We propose that Rap1 regulates the expression of N-cadherin during embryonic development, which affects ß-catenin expression. Beta-catenin in turn regulates cytoskeletal protein expression, ultimately affecting neuronal morphology and migration.

Effect of sonic hedgehog on motor neuron positioning in the spinal cord during chicken embryonic development.

Sonic hedgehog (SHH) is a vertebrate homologue of the secreted Drosophila protein hedgehog and is expressed by the notochord and floor plate in the developing spinal cord. Sonic hedgehog provides signals relevant for positional information, cell proliferation and possibly cell survival, depending on the time and location of expression. Although the role of SHH in providing positional information in the neural tube has been experimentally proven, the underlying mechanism remains unclear. In this study, in ovo electroporation was employed in the chicken spinal cord during chicken embryo development. Electroporation was conducted at stage 17 (E2.5), after electroporation the embryos were continued incubating to stage 28 (E6) for sampling, tissue fixation with 4% paraformaldehyde and frozen sectioning. Sonic hedgehog and related protein expressions were detected by in situ hybridization and fluorescence immunohistochemistry and the results were analysed after microphotography. Our results indicate that the ectopic expression of SHH leads to ventralization in the spinal cord during chicken embryonic development by inducing abnormalities in the structure of the motor column and motor neuron integration. In addition, ectopic SHH expression inhibits the expression of dorsal transcription factors and commissural axon projections. The correct location of SHH expression is vital to the formation of the motor column. Ectopic expression of SHH in the spinal cord not only affects the positioning of motor neurons, but also induces abnormalities in the structure of the motor column. It leads to ventralization in the spinal cord, resulting in the formation of more ventral neurons forming during neuronal formation.

Organotypic slice culture based on in ovo electroporation for chicken embryonic central nervous system.

Organotypic slice culture is a living cell research technique which blends features of both in vivo and in vitro techniques. While organotypic brain slice culture techniques have been well established in rodents, there are few reports on the study of organotypic slice culture, especially of the central nervous system (CNS), in chicken embryos. We established a combined in ovo electroporation and organotypic slice culture method to study exogenous genes functions in the CNS during chicken embryo development. We performed in ovo electroporation in the spinal cord or optic tectum prior to slice culture. When embryonic development reached a specific stage, green fluorescent protein (GFP)-positive embryos were selected and fluorescent expression sites were cut under stereo fluorescence microscopy. Selected tissues were embedded in 4% agar. Tissues were sectioned on a vibratory microtome and 300 µm thick sections were mounted on a membrane of millicell cell culture insert. The insert was placed in a 30-mm culture dish and 1 ml of slice culture media was added. We show that during serum-free medium culture, the slice loses its original structure and propensity to be strictly regulated, which are the characteristics of the CNS. However, after adding serum, the histological structure of cultured-tissue slices was able to be well maintained and neuronal axons were significantly longer than that those of serum-free medium cultured-tissue slices. As the structure of a complete single neuron can be observed from a slice culture, this is a suitable way of studying single neuronal dynamics. As such, we present an effective method to study axon formation and migration of single neurons in vitro.

Effects of N-cadherin on neuronal migration during chicken optic tectum development.

N-cadherin, a member of the cadherin family, plays an important role in neural development. In addition, N-cadherin has been reported to be crucial in neuronal migration, axonal outgrowth, and axonal path-finding. However, the mechanism underlying the effects of N-cadherin in neuronal migration is not entirely clear. In this study, we investigated the overexpression or knockdown of N-cadherin in the optic tectum during chicken embryo development, and then analyzed the effect of N-cadherin on neuronal migration. The results showed that compared with the control group, in the N-cadherin knockdown group, the neuronal migration of the optic tectum was significantly affected and could not arrive at destination. The stratum griseum central layer of the optic tectum mainly includes multipolar neurons, which could not be formed after the knockdown of N-cadherin, and more neurons form the bipolar or monopolar neurons compared with the control group. Compared with the control group, more cells stayed in the neuroepithelium layer. The axonal length in the optic tectum was significantly (P < 0.001) shorter in the N-cadherin knockdown group than in the control group. These results reveal that the knockdown of N-cadherin mainly affects the length of axons and formation of multipolar neurons in the development of the chicken optic tectum, which eventually results in the inhibition of neuronal migration.

N-Cadherin Upregulation Promotes the Neurogenic Differentiation of Menstrual Blood-Derived Endometrial Stem Cells.

Peripheral nerve injuries are typically caused by either trauma or medical disorders, and recently, stem cell-based therapies have provided a promising treatment approach. Menstrual blood-derived endometrial stem cells (MenSCs) are considered an ideal therapeutic option for peripheral nerve repair due to a noninvasive collection procedure and their high proliferation rate and immunological tolerance. Here, we successfully isolated MenSCs and examined their biological characteristics including their morphology, multipotency, and immunophenotype. Subsequent in vitro studies demonstrated that MenSCs express high levels of neurotrophic factors, such as NT3, NT4, BDNF, and NGF, and are capable of transdifferentiating into glial-like cells under conventional induction conditions. Moreover, upregulation of N-cadherin (N-cad) mRNA and protein expression was observed after neurogenic differentiation. In vivo studies clearly showed that N-cad knockdown via in utero electroporation perturbed the migration and maturation of mouse neural precursor cells (NPCs). Finally, a further transfection assay also confirmed that N-cad upregulation in MenSCs results in the expression of S100. Collectively, our results confirmed the paracrine effect of MenSCs on neuroprotection as well as their potential for transdifferentiation into glial-like cells and demonstrated that N-cad upregulation promotes the neurogenic differentiation of MenSCs, thereby providing support for transgenic MenSC-based therapy for peripheral nerve injury.

Wnt3a Ectopic Expression Interferes Axonal Projection and Motor Neuron Positioning During the Chicken Spinal Cord Development.

The formation of dorsal-ventral axis of the spinal cord is controlled largely by dorsal signals such as Wnts (which are members of the wingless + MMTV integrants, Int family), besides ventral signals such as sonic hedgehog (Shh). Wnt3a, one of the Wnt family members, is involved in multiple cellular functions, including self-renewal, proliferation, differentiation, and motility. Here, we aim to study the mechanism of the regulation of chicken spinal cord patterning by Wnt3a. In this study, Wnt3a was ectopically expressed in the spinal cord of developing chicken embryos by in ovo electroporation. The results of immunofluorescent staining revealed that Wnt3a ectopic expression caused the abnormality of commissural axonal projection and the formation of nerve fibers was interrupted. It is worth noting that neurons in the ventricular zone, especially motor neurons, could not migrate laterally after the Wnt3a overexpression, which led to the malformation of motor column. In addition, we found that neurons could not protrude axons outwardly after overexpression of Wnt3a in the spinal cord. It was also found that Wnt3a overexpression inhibited the outgrowth of processes in culturing SH-SY5Y cells. In conclusion, we proposed that Wnt3a regulates neuronal morphology, which subsequently disrupts axonal projection and motor neuron positioning during spinal cord development.

Sonic Hedgehog Regulation of the Neural Precursor Cell Fate During Chicken Optic Tectum Development.

During nervous system development, neurons project axons over long distances to reach the appropriate targets for correct neural circuit formation. Sonic hedgehog (Shh) is a secreted protein and plays a key role in regulating vertebrate embryogenesis, especially in central nervous system (CNS) patterning, including neuronal migration and axonal projection in the brain and spinal cord. In the developing ventral midbrain, Shh is sufficient to specify a striped pattern of cell fates. Little is known about the molecular mechanisms underlying the Shh regulation of the neural precursor cell fate during the optic tectum development. Here, we aimed at studying how Shh might regulate chicken optic tectum patterning. In the present study, in ovo electroporation methods were employed to achieve the overexpression of Shh in the optic tectum during chicken embryo development. Besides, the study combined in ovo electroporation and neuron isolation culturing to study the function of Shh in vivo and in vitro. The fluorescent immunohistochemistry methods were used to check the related indicators. The results showed that Shh overexpression caused 87.8% of cells to be distributed to the stratum griseum central (SGC) layer, while only 39.3% of the GFP-transfected cells resided in the SGC layer in the control group. Shh overexpression also reduced the axon length in vivo and in vitro. In conclusion, we provide evidence that Shh regulates the neural precursor cell fate during chicken optic tectum development. Shh overexpression impairs neuronal migration and may affect the fate determination of transfected neurons.