ROS-mediated lysosomal membrane permeabilization and autophagy inhibition regulate bleomycin-induced cellular senescence.

Bleomycin exhibits effective chemotherapeutic activity against multiple types of tumors, and also induces various side effects, such as pulmonary fibrosis and neuronal defects, which limit the clinical application of this drug. Macroautophagy/autophagy has been recently reported to be involved in the functions of bleomycin, and yet the mechanisms of their crosstalk remain insufficiently understood. Here, we demonstrated that reactive oxygen species (ROS) produced during bleomycin activation hampered autophagy flux by inducing lysosomal membrane permeabilization (LMP) and obstructing lysosomal degradation. Exhaustion of ROS with N-acetylcysteine relieved LMP and autophagy defects. Notably, we observed that LMP and autophagy blockage preceded the emergence of cellular senescence during bleomycin treatment. In addition, promoting or inhibiting autophagy-lysosome degradation alleviated or exacerbated the phenotypes of senescence, respectively. This suggests the alternation of autophagy activity is more a regulatory mechanism than a consequence of bleomycin-induced cellular senescence. Taken together, we reveal a specific role of bleomycin-induced ROS in mediating defects of autophagic degradation and further regulating cellular senescence in vitro and in vivo. Our findings, conversely, indicate the autophagy-lysosome degradation pathway as a target for modulating the functions of bleomycin. These provide a new perspective for optimizing bleomycin as a clinically applicable chemotherapeutics devoid of severe side-effects.Abbreviations: AT2 cells: type II alveolar epithelial cells; ATG7: autophagy related 7; bEnd.3: mouse brain microvascular endothelial cells; BNIP3L: BCL2/adenovirus E1B interacting protein 3-like; CCL2: C-C motif chemokine ligand 2; CDKN1A: cyclin dependent kinase inhibitor 1A; CDKN2A: cyclin dependent kinase inhibitor 2A; FTH1: ferritin heavy polypeptide 1; γ-H2AX: phosphorylated H2A.X variant histone; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; HUVEC: human umbilical vein endothelial cells; HT22: hippocampal neuronal cell lines; Il: interleukin; LAMP: lysosomal-associated membrane protein; LMP: lysosome membrane permeabilization; MTORC1: mechanistic target of rapamycin kinase complex 1; NAC: N-acetylcysteine; NCOA4: nuclear receptor coactivator 4; PI3K: phosphoinositide 3-kinase; ROS: reactive oxygen species; RPS6KB/S6K: ribosomal protein S6 kinase; SA-GLB1/ß-gal: senescence-associated galactosidase, beta 1; SAHF: senescence-associated heterochromatic foci; SASP: senescence-associated secretory phenotype; SEC62: SEC62 homolog, preprotein translocation; SEP: superecliptic pHluorin; SQSTM1/p62: sequestosome 1; TFEB: transcription factor EB.

Generation of an induced pluripotent stem cell (iPSC) line from a Parkinson's disease patient with a pathogenic LRP10/c.688C > T(p.Arg230Trp) mutation.

Parkinson's disease (PD) is a highly prevalent and severe neurodegenerative disease that affects more than 10 million individuals worldwide. Pathogenic mutations in LRP10 have been associated with autosomal dominant PD. Here, we report an induced pluripotent stem cell (iPSC) line generated from a PD patient harboring the LRP10 c.688C > T (p.Arg230Trp) variant. Skin fibroblasts from the PD patient were successfully reprogrammed into iPSCs that expressed pluripotency markers, a normal karyotype, and the capacity to differentiate into the three germ layers in vivo. This iPSC line is a potential resource for studying the pathogenic mechanisms of PD.

Epigenetic modification in Parkinson's disease.

Parkinson's disease (PD) is a common neurodegenerative disorder caused by genetic, epigenetic, and environmental factors. Recent advance in genomics and epigenetics have revealed epigenetic mechanisms in PD. These epigenetic modifications include DNA methylation, post-translational histone modifications, chromatin remodeling, and RNA-based mechanisms, which regulate cellular functions in almost all cells. Epigenetic alterations are involved in multiple aspects of neuronal development and neurodegeneration in PD. In this review, we discuss current understanding of the epigenetic mechanisms that regulate gene expression and neural degeneration and then highlight emerging epigenetic targets and diagnostic and therapeutic biomarkers for treating or preventing PD.

Genetic analysis of the LRP10 gene in Chinese patients with Parkinson's disease.

BACKGROUND: Parkinson's disease (PD) is a neurodegenerative disorder characterized by resting tremor, bradykinesia, muscle rigidity, and abnormal gait. The low-density lipoprotein receptor-related protein 10 (LRP10) was recently shown to be a causal gene for PD, and different ethnic cohorts have distinct frequencies and spectrum of LRP10 variants. METHODS: We sequenced the full coding regions and exon-intron boundaries of LRP10 in 129 patients with sporadic Chinese PD to further investigate the connection of LRP10 with PD in a sample of Chinese patients. RESULTS: In this study, we identified four potentially pathogenic mutations, including one novel mutation of p.Gly328Asp and three known mutations of p.Cys165Tyr, p.Arg230Trp, and p.Arg661His in four of the 129 Chinese patients with PD. CONCLUSION: According to our study, the LRP10 gene may attribute to PD pathogenesis.

Tracking of Stem Cells from Human Exfoliated Deciduous Teeth Labeled with Molday ION Rhodamine-B during Periodontal Bone Regeneration in Rats.

Background and Objectives: Chronic periodontitis can lead to alveolar bone resorption and eventually tooth loss. Stem cells from exfoliated deciduous teeth (SHED) are appropriate bone regeneration seed cells. To track the survival, migration, and differentiation of the transplanted SHED, we used super paramagnetic iron oxide particles (SPIO) Molday ION Rhodamine-B (MIRB) to label and monitor the transplanted cells while repairing periodontal bone defects. Methods and Results: We determined an appropriate dose of MIRB for labeling SHED by examining the growth and osteogenic differentiation of labeled SHED. Finally, SHED was labeled with 25 µg Fe/ml MIRB before being transplanted into rats. Magnetic resonance imaging was used to track SHED survival and migration in vivo due to a low-intensity signal artifact caused by MIRB. HE and immunohistochemical analyses revealed that both MIRB-labeled and unlabeled SHED could promote periodontal bone regeneration. The colocalization of hNUC and MIRB demonstrated that SHED transplanted into rats could survive in vivo. Furthermore, some MIRB-positive cells expressed the osteoblast and osteocyte markers OCN and DMP1, respectively. Enzyme-linked immunosorbent assay revealed that SHED could secrete protein factors, such as IGF-1, OCN, ALP, IL-4, VEGF, and bFGF, which promote bone regeneration. Immunofluorescence staining revealed that the transplanted SHED was surrounded by a large number of host-derived Runx2- and Col II-positive cells that played important roles in the bone healing process. Conclusions: SHED could promote periodontal bone regeneration in rats, and the survival of SHED could be tracked in vivo by labeling them with MIRB. SHED are likely to promote bone healing through both direct differentiation and paracrine mechanisms.

Anticancer effects and mechanisms of astragaloside­IV (Review).

Astragalus membranaceus Bunge is widely used in Traditional Chinese Medicine to treat various cancers. Astragaloside­IV (AS­IV) is one of the major compounds isolated from A. membranaceus Bunge and has been demonstrated to have antitumor effects by inhibiting cell proliferation, invasion and metastasis in various cancer types. Numerous studies have used in vitro cell culture and in vivo animal models of cancer to explore the antitumor activities of AS­IV. In the present study, the antitumor effects and mechanisms of AS­IV reported in studies recorded in the PubMed database were reviewed. First, the antitumor effects of AS­IV on proliferation, cell cycle, apoptosis, autophagy, invasion, migration, metastasis and epithelial­mesenchymal transition processes in cancer cells and the tumor microenvironment, including angiogenesis, tumor immunity and macrophage­related immune responses to cancer cells, were comprehensively discussed. Subsequently, the molecular mechanisms and related signaling pathways associated with antitumor effects of AS­IV as indicated by in vitro and in vivo studies were summarized, including the Wnt/AKT/GSK-3ß (glycogen synthase kinase­3ß)/ß­catenin, TGF­ß/PI3K/AKT/mTOR, PI3K/MAPK/mTOR, PI3K/AKT/NF­κB, Rac family small GTPase 1/RAS/MAPK/ERK, TNF­α/protein kinase C/ERK1/2­NF­κB and Tregs (T­regulatory cells)/IL­11/STAT3 signaling pathways. Of note, several novel mechanisms of Toll­like receptor 4 (TLR4)/NF­κB/STAT3, pSmad3C/3L, nuclear factor erythroid 2­related factor (NrF2)/heme oxygenase 1, circDLST/microRNA­489­3p/eukaryotic translation initiation factor 4A1 and macrophage­related high­mobility group box 1­TLR4 signaling pathways associated with the anticancer activity of AS­IV were also included. Finally, the limitations of current studies that must be addressed in future studies were pointed out to facilitate the establishment of AS­IV as a potent therapeutic drug in cancer treatment.

Anxiolytic effect of YangshenDingzhi granules: Integrated network pharmacology and hippocampal metabolomics.

Anxiety disorder is one of the most common mental diseases. It is mainly characterized by a sudden, recurring but indescribable panic, fear, tension and/or anxiety. Yangshendingzhi granules (YSDZ) are widely used in the treatment of anxiety disorders, but its active ingredients and underlying mechanisms are not yet clear. This study integrates network pharmacology and metabolomics to investigate the potential mechanism of action of YSDZ in a rat model of anxiety. First, potential active ingredients and targets were screened by network pharmacology. Then, predictions were verified by molecular docking, molecular dynamics and western blotting. Metabolomics was used to identify differential metabolites and metabolic pathways. All results were integrated for a comprehensive analysis. Network pharmacology analysis found that Carotene, ß-sitosterol, quercetin, Stigmasterol, and kaempferol in YSDZ exert anxiolytic effects mainly by acting on IL1ß, GABRA1, PTGS1, ESR1, and TNF targets. Molecular docking results showed that all the affinities were lower than -5 kcal/mol, and the average affinities were -7.7764 kcal/mol. Molecular dynamics simulation results showed that RMSD was lower than 2.5 A, and the overall conformational changes of proteins were small, indicating that the small molecules formed stable complexes with proteins. The results of animal experiments showed that YSDZ exerts anxiolytic effects by regulating GABRA1 and TNF-α, ameliorating pathological damage in hippocampal CA1, and regulating metabolic pathways such as thiamine, cysteine and methionine metabolism, lysine biosynthesis and degradation. Altogether, we reveal multiple mechanisms through which YSDZ exerts its anti-anxiety effects, which may provide a reference for its clinical application and drug development.

Establishment and characterization of human induced pluripotent stem cell line from a Parkinson's disease patient harboring VPS13A gene mutation.

Mutations in VPS13 gene have been recently reported as a genetic cause of Parkinson's disease (PD). In this study, we isolated the skin fibroblasts from a PD patient harboring VPS13A gene mutation (c. 4282_4289delinsA) and reprogrammed the fibroblasts to a novel patient-specific induced pluripotent stem cell (iPSC) line LCPHi002-A using transgene-free episomal plasmids to express OCT3/4, SOX2, KLF4, L-MYC, and LIN28. The LCPHi002-A line showed the normal karyotype, expression of pluripotency markers, and had multi-lineage differentiation capacity in vivo. This iPSC line of LCPHi002-A could be used for studying pathogenic mechanisms of PD.

[Experimental study on transplantation of MIRB labeled human deciduous dental pulp stem cells to repair periodontal bone defects in rats].

PURPOSE: To trace the fate of transplanted stem cells from human exfoliated deciduous teeth (SHED) in the repair of periodontal bone defects, Molday ION rhodamine B (MIRB) was used to label SHED and explore the mechanism of SHED in the repair of periodontal bone defects. METHODS: In vitro cultured SHED were labeled by MIRB. The labeling efficiency, cell survival, proliferation and osteogenic differentiation of MIRB-labelled SHED were detected. The labeled cells were transplanted into the rat model with periodontal bone defect. The survival, differentiation and improvement of host periodontal bone healing of MIRB labeled SHED in vivo were analyzed by immunohistochemistry and fluorescence co-staining, nuclear magnetic imaging dual-mode tracking and H-E staining. The data were statistically analyzed with SPSS 24.0 software package. RESULTS: MIRB labeled SHED did not affect its growth and osteogenic differentiation. The optimal labeling concentration was 25 µg/mL, the labeling efficiency of SHED reached 100%. The transplantation of MIRB labeled SHED in vivo can survive for more than 8 weeks. It was found that MIRB labeled SHED could differentiate into osteoblasts in vivo and significantly promote the repair of alveolar bone defects. CONCLUSIONS: MIRB labeled SHED can be traced in vivo, and the effect of labeled SHED on the repair of defective alveolar bone was observed.

Current Approaches and Molecular Mechanisms for Directly Reprogramming Fibroblasts Into Neurons and Dopamine Neurons.

Parkinson's disease is mainly caused by specific degeneration of dopaminergic neurons (DA neurons) in the substantia nigra of the middle brain. Over the past two decades, transplantation of neural stem cells (NSCs) from fetal brain-derived neural stem cells (fNSCs), human embryonic stem cells (hESCs), and induced pluripotent stem cells (iPSCs) has been shown to improve the symptoms of motor dysfunction in Parkinson's disease (PD) animal models and PD patients significantly. However, there are ethical concerns with fNSCs and hESCs and there is an issue of rejection by the immune system, and the iPSCs may involve tumorigenicity caused by the integration of the transgenes. Recent studies have shown that somatic fibroblasts can be directly reprogrammed to NSCs, neurons, and specific dopamine neurons. Directly induced neurons (iN) or induced DA neurons (iDANs) from somatic fibroblasts have several advantages over iPSC cells. The neurons produced by direct transdifferentiation do not pass through a pluripotent state. Therefore, direct reprogramming can generate patient-specific cells, and it can overcome the safety problems of rejection by the immune system and teratoma formation related to hESCs and iPSCs. However, there are some critical issues such as the low efficiency of direct reprogramming, biological functions, and risks from the directly converted neurons, which hinder their clinical applications. Here, the recent progress in methods, mechanisms, and future challenges of directly reprogramming somatic fibroblasts into neurons or dopamine neurons were summarized to speed up the clinical translation of these directly converted neural cells to treat PD and other neurodegenerative diseases.

Current treatment strategies for COVID­19 (Review).

The spread of the novel severe acute respiratory syndrome coronavirus 2 (SARS­CoV­2) emerged suddenly at the end of 2019 and the disease came to be known as coronavirus disease 2019 (COVID­19). To date, there is no specific therapy established to treat COVID­19. Identifying effective treatments is urgently required to treat patients and stop the transmission of SARS­CoV­2 in humans. For the present review, >100 publications on therapeutic agents for COVID­19, including in vitro and in vivo animal studies, case reports, retrospective analyses and meta­analyses were retrieved from PubMed and analyzed, and promising therapeutic agents that may be used to combat SARS­CoV­2 infection were highlighted. Since the outbreak of COVID­19, different drugs have been repurposed for its treatment. Existing drugs, including chloroquine (CQ), its derivative hydroxychloroquine (HCQ), remdesivir and nucleoside analogues, monoclonal antibodies, convalescent plasma, Chinese herbal medicine and natural compounds for treating COVID­19 evaluated in experimental and clinical studies were discussed. Although early clinical studies suggested that CQ/HCQ produces antiviral action, later research indicated certain controversy regarding their use for treating COVID­19. The molecular mechanisms of these therapeutic agents against SARS­CoV2 have been investigated, including inhibition of viral interactions with angiotensin­converting enzyme 2 receptors in human cells, viral RNA­dependent RNA polymerase, RNA replication and the packaging of viral particles. Potent therapeutic options were reviewed and future challenges to accelerate the development of novel therapeutic agents to treat and prevent COVID­19 were acknowledged.

Generation of integration-free human iPSC line LCPHi001-A from a Parkinson's disease patient carrying the RecNciI mutation in GBA gene.

Parkinson's disease (PD) is a neurodegenerative disease caused by environmental and genetic factors. The identified PD genes include SNCA, LRRK2, Parkin, DJ-1, PINK1, and ATP13A2. Mutations in the glucocerebrosidase (GBA) gene were reported to be associated with PD in different ethnic populations. Here we generated a novel induced pluripotent stem cell (iPSC) line LCPHi001-A from a PD patient carrying RecNciI mutation (c.1448 T > C, c.1483G > C, and c.1497G > C) in GBA by non-integrative episomal plasmids. The LCPHi001-A line expressed pluripotency markers, displayed differentiation capacity to three germ layers in vivo, and had the normal karyotype.

Introduction for Stem Cell-Based Therapy for Neurodegenerative Diseases.

Neurodegenerative diseases (NDs) are a group of neurological diseases caused by the progressive degeneration of neurons and glial cells in the brain and spinal cords. Usually there is a selective loss of specific neuronal cells in a restricted brain area from any neurodegenerative diseases, such as dopamine (DA) neuron death in Parkinson disease (PD) and motor neuron loss in amyotrophic lateral sclerosis (ALS), or a widespread degeneration affecting many types of neurons in Alzheimer's disease (AD). As there is no effective treatment to stop the progression of these neurodegenerative diseases, stem cell-based therapies have provided great potentials for these disorders. Currently transplantation of different stem cells or their derivatives has improved neural function in animal models of neurodegenerative diseases by replacing the lost neural cells, releasing cytokines, modulation of inflammation, and mediating remyelination. With the advance in somatic cell reprogramming to generate induced pluripotent stem cells (iPS cells) and directly induced neural stem cells or neurons, pluripotent stem cell can be induced to differentiate to any kind of neural cells and overcome the immune rejection of the allogeneic transplantation. Recent studies have proved the effectiveness of transplanted stem cells in animal studies and some clinical trials on patients with NDs. However, some significant hurdles need to be resolved before these preclinical results can be translated to clinic. In particular, we need to better understand the molecular mechanisms of stem cell transplantation and develop new approaches to increase the directed neural differentiation, migration, survival, and functional connections of transplanted stem cells in the pathological environment of the patient's central nerve system.

Quality Standards of Stem Cell Sources for Clinical Treatment of Neurodegenerative Diseases.

A large number of experimental and clinical studies have shown that cell transplantation has therapeutic effects for PD, AD and other neurodegenerative diseases or damages. Good Manufacturing Practice (GMP) guidance must be defined to produce clinical-grade cells for transplantation to the patients. Standardized quality and clinical preparation procedures of the transplanted cells will ensure the therapeutic efficacy and reduce the side-effect risk of cell therapy. Here we review the cell quality standards governing the clinical transplantation of stem cells for neurodegenerative diseases to clinical practitioners. These quality standards include cell quality control, minimal suggested cell doses for undergoing cell transplantation, documentation of procedure and therapy, safety evaluation, efficacy evaluation, policy of repeated treatments, not charging the patients for unproven therapies, basic principles of cell therapy, and publishing responsibility.

Stem Cell Therapy for Parkinson's Disease.

Parkinson's disease (PD) is one of the most common neurodegenerative diseases caused by specific degeneration and loss of dopamine neurons in substantia nigra of the midbrain. PD is clinically characterized by motor dysfunctions and non-motor symptoms. Even though the dopamine replacement can improve the motor symptoms of PD, it cannot stop the neural degeneration and disease progression. Electrical deep brain stimulation (DBS) to the specific brain areas can improve the symptoms, but it eventually loses the effectiveness. Stem cell transplantation provides an exciting potential for the treatment of PD. Current available cell sources include neural stem cells (NSCs) from fetal brain tissues, human embryonic stem cells (hESCs) isolated from blastocyst, and induced pluripotent stem cells (iPSCs) reprogrammed from the somatic cells such as the fibroblasts and blood cells. Here, we summarize the research advance in experimental and clinical studies to transplant these cells into animal models and clinical patients, and specifically highlight the studies to use hESCs /iPSCs-derived dopaminergic precursor cells and dopamine neurons for the treatment of PD, at last propose future challenges for developing clinical-grade dopaminergic cells for treating the PD.

Stem Cell Therapy for Alzheimer's Disease.

Alzheimer's disease (AD) is the most common neurodegenerative disease caused by eventually aggregated amyloid ß (Aß) plaques in degenerating neurons of the aging brain. These aggregated protein plaques mainly consist of Aß fibrils and neurofibrillary tangles (NFTs) of phosphorylated tau protein. Even though some cholinesterase inhibitors, NMDA receptor antagonist, and monoclonal antibodies were developed to inhibit neurodegeneration or activate neural regeneration or clear off the Aß deposits, none of the treatment is effective in improving the cognitive and memory dysfunctions of the AD patients. Thus, stem cell therapy represents a powerful tool for the treatment of AD. In addition to discussing the advents in molecular pathogenesis and animal models of this disease and the treatment approaches using small molecules and immunoglobulins against AD, we will focus on the stem cell sources for AD using neural stem cells (NSCs); embryonic stem cells (ESCs); and mesenchymal stem cells (MSCs) from bone marrow, umbilical cord, and umbilical cord blood. In particular, patient-specific-induced pluripotent stem cells (iPS cells) are proposed as a future prospective and the challenges for the treatment of AD.

Cell-Based Therapy for Spinal Muscular Atrophy.

Spinal muscular atrophy (SMA) is a devastating neurodegenerative disease characterized by the degeneration of lower motor neurons in the spinal cord, leading to progressive paralysis and early death in the severe cases. SMA is primarily caused by the mutations in the gene of SMN (survival motor neuron). More research has focused on the development of SMN-targeted replacement therapy for SMA. The first US Food and Drug Administration (FDA)-approved modified antisense oligonucleotide (nusinersen) to treat SMA is to reverse intronic splicing silencer of SMN to produce fully functional SMN2. Recently, stem cell transplantation has shown the potential to repair the injured tissue and differentiate into neurons to rescue the phenotypes of SMA in animal models. In this chapter, we first review the clinical, genetic, and pathogenic mechanisms of SMA. Then, we discuss current pharmacological treatments and point out the therapeutic efficacy of stem cell transplantation and future directions and priorities for SMA.

Stem Cell Transplantation Therapy for Retinal Degenerative Diseases.

In the past decade, progress in the research on human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) has provided the solid basis to derive retinal pigment epithelium, photoreceptors, and ganglion cells from hESCs/iPSCs for transplantation therapy of retinal degenerative diseases (RDD). Recently, the iPSC-derived retinal pigment epithelium cells have achieved efficacy in treating patients with age-related macular degeneration (AMD). However, there is still much work to be done about the differentiation of hESCs/iPSCs into clinically required retinal cells and improvement in the methods to deliver the cells into the retina of patients. Here we will review the research advances in stem cell transplantation in animal studies and clinical trials as well as propose the challenges for improving the clinical efficacy and safety of hESCs/iPSCs-derived retinal neural cells in treating retinal degenerative diseases.

Future Challenges and Perspectives for Stem Cell Therapy of Neurodegenerative Diseases.

Stem cell-based therapy has shown exciting efficacy in pre-clinical studies on different neurodegenerative diseases (NDs). However, no clinically applicable stem-cell-derived neurons are available to the patients with NDs. There exist some obstacles associated with stem cell therapy, which need to be overcome in future clinical studies. In this chapter, more challenges and new strategies will be explored to accelerate the clinical translation of a human embryonic stem cell (hESC)/induced pluripotent stem cell (iPSC)-derived neural cell product to patients with NDs.

The Interaction of EphA4 With PDGFRß Regulates Proliferation and Neuronal Differentiation of Neural Progenitor Cells in vitro and Promotes Neurogenesis in vivo.

Neural progenitor cells (NPCs) have great potentials in cell replacement therapy for neurodegenerative diseases, such as Alzheimer's disease (AD), by promoting neurogenesis associated with hippocampal memory improvement. Ephrin receptors and angiogenic growth factor receptors have a marked impact on the proliferation and differentiation of NPCs. Although ephrin receptor A4 (EphA4) was shown to directly interact with platelet-derived growth factor receptor ß (PDGFRß), the functional effects of this interaction on neurogenesis in cultured NPCs and adult hippocampus have not yet been studied. Immunoprecipitation demonstrated that EphA4 directly interacted with PDGFRß in NPCs under ligand stimulation. Ephrin-A1 and PDGF-platelet-derived growth factor BB (BB) significantly increased proliferation and neuronal differentiation of NPCs, which was further augmented by combined treatment of Ephrin-A1 and PDGF-BB. We also found that ligand-dependent proliferation and neuronal differentiation were inhibited by the dominant-negative EphA4 mutant or a PDGFR inhibitor. Most importantly, injection of ephrin-A1 and/or PDGF-BB promoted hippocampal NPC proliferation in the APP/PS1 mouse model of AD, indicating that direct interaction of EphA4 with PDGFRß plays a functional role on neurogenesis in vivo. Finally, studies in NPCs showed that the EphA4/PDGFRß/FGFR1/FRS2α complex formed by ligand stimulation is involved in neurogenesis via ERK signaling. The present findings provided a novel insight into the functional role of direct interaction of EphA4 and PDGFRß in neurogenesis, implicating its potential use for treating neurodegenerative diseases.