Retinoic acid induces differentiation of cochlear neural progenitor cells into hair cells / O ácido retinoico induz a diferenciação das células progenitoras neurais cocleares em células ciliadas

Abstract Introduction: Inner ear progenitor cells have the potential for multi-directional differentiation. Retinoic acid is an important requirement for the development of the inner ear. Blocking the Curtyr's retinoic acid signaling pathway can significantly reduce the number of hair cells. Therefore, we believe that retinoic acid may induce the regeneration of inner ear hair cells. Objective: To investigate whether the cochlear neural progenitor cells maintain the characteristics of stem cells during recovery and subculture, whether retinoic acid can induce cochlear neural progenitor cells into hair cells in vitro, and whether retinoic acid promotes or inhibits the proliferation of cochlear neural progenitor cells during differentiation. Methods: Cochlear neural progenitor cells were cultured and induced in DMEM/F12 + RA (10−6M) and then detected the expressions of hair cell markers (Math1 and MyosinVIIa) by immunofluorescence cytochemistry and realtime-polymerase chain reaction, and the proliferation of cochlear neural progenitor cells was detected by Brdu. Results: The nestin of cochlear neural progenitor cells was positively expressed. The ratios of Math1-positive cells in the control group and experimental group were 1.5% and 63%, respectively; the ratios of MyosinVIIa-positive cells in the control group and experimental group were 0.96% and 56%, respectively (p <0.05). The ratios of Brdu+-labeled cells in retinoic acid group, group PBS, and group FBS were 20.6%, 29.9%, and 54.3%, respectively; however, the proliferation rate in the experimental group decreased. Conclusion: Retinoic acid can promote cochlear neural progenitor cells to differentiate into the hair cells.

Resumo Introdução: As células progenitoras da orelha interna têm potencial para diferenciação multidirecional. O ácido retinoico é uma condição importante para o desenvolvimento da orelha interna. O bloqueio da via de sinalização do ácido retinoico no órgão de Corti pode reduzir significativamente o número de células ciliadas. Portanto, acreditamos que o ácido retinoico pode induzir a regeneração das células ciliadas do ouvido interno. Objetivo: Investigar se as células progenitoras neurais cocleares mantêm as características das células-tronco durante a recuperação e subcultura, se o ácido retinoico pode induzir a transformação de células progenitoras neurais cocleares em células ciliadas in vitro e se o ácido retinoico promove ou inibe a proliferação das células progenitoras durante a diferenciação. Método: As células progenitoras neurais cocleares foram cultivadas e induzidas em DMEM/F12+AR (106M) e, então, foram detectadas as expressões de marcadores das células ciliadas (Math1 e Myosin?a) com o uso de citoquímica por imunofluorescência e real time -polymerase chain reaction e a proliferação de células progenitoras neurais cocleares foi detectada pelo teste Brdu. Resultados: A nestina das células progenitoras neurais cocleares foi expressa positivamente. As proporções de células positivas para Math1 no grupo controle e no grupo experimental foram 1,5% e 63%, respectivamente; as proporções de células positivas para Myosin?a no grupo controle e no grupo experimental foram de 0,96% e 56%, respectivamente (p <0,05). As proporções de células marcadas com Brdu+ no grupo ácido retinoico, grupo PBS e grupo FBS foram de 20,6%, 29,9% e 54,3%, respectivamente; no entanto, a taxa de proliferação no grupo experimental diminuiu. Conclusões: O ácido retinoico pode promover a diferenciação das células progenitoras neurais cocleares em células ciliadas.

The COMPASS Core Member Ash2l Regulates the Cell Cycle of Neural Progenitor Cells / 中国生物化学与分子生物学报

To investigate the role of Ash2l (absent, small, or homeotic 2-like, Ash2l) on the proliferation ability and cell cycle of mouse cerebral cortical neural progenitor cells (NPCs), We examined the number and distribution of NPCs, using the radial glial cell marker PAX6 and intermediate progenitor cell marker TBR2. E16. 5 mice were labeled with EdU for 30 min to detect the proliferation ability of NPCs. Conditional knockout of Ash2l resulted in a dramatic reduction in the number of NPCs and a disordered distribution. The 30 min EdU insertion experiment showed that EdU could hardly be inserted into NPCs, indicating that the proliferation ability of NPCs was severely affected. Using the mitotic cell cycle marker pH3, the distribution of dividing NPCs was observed. We then detected the expressed level of Cyclin A by Western blotting. The distribution of cell nuclei of M-phase is disordered and the expression of G

Transcriptome Analysis Identifies SenZfp536, a Sense LncRNA that Suppresses Self-renewal of Cortical Neural Progenitors / 神经科学通报·英文版

Long non-coding RNAs (lncRNAs) regulate transcription to control development and homeostasis in a variety of tissues and organs. However, their roles in the development of the cerebral cortex have not been well elucidated. Here, a bioinformatics pipeline was applied to delineate the dynamic expression and potential cis-regulating effects of mouse lncRNAs using transcriptome data from 8 embryonic time points and sub-regions of the developing cerebral cortex. We further characterized a sense lncRNA, SenZfp536, which is transcribed downstream of and partially overlaps with the protein-coding gene Zfp536. Both SenZfp536 and Zfp536 were predominantly expressed in the proliferative zone of the developing cortex. Zfp536 was cis-regulated by SenZfp536, which facilitates looping between the promoter of Zfp536 and the genomic region that transcribes SenZfp536. Surprisingly, knocking down or activating the expression of SenZfp536 increased or compromised the proliferation of cortical neural progenitor cells (NPCs), respectively. Finally, overexpressing Zfp536 in cortical NPCs reversed the enhanced proliferation of cortical NPCs caused by SenZfp536 knockdown. The study deepens our understanding of how lncRNAs regulate the propagation of cortical NPCs through cis-regulatory mechanisms.

Therapeutic potentials of neural stem cells in Alzheimer’s disease

@#The commonest cause of dementia among the elderly population is Alzheimer’s disease (AD). It is a health concern globally as the number of people affected by dementia worldwide is rapidly increasing. Several genes have been linked to AD and the pathogenesis of the disease has been extensively and vigorously examined. Thus far, only a few drugs have been approved by the Food and Drug Administration (FDA) for the pharmacological treatment of AD and a growing body of research has turned to alternative options such as stem cell therapy. This review will give an overview of the pathological and clinical aspects of AD. Although researchers have explored the suitability and feasibility of using various types of stems cells to treat AD, this review will focus mainly on neural stem cells (NSCs)/ neural progenitor cells (NPCs). The behaviour and properties of NSCs will be described, accompanied by a comprehensive discussion of the therapeutic strategies involving the use of NSCs/NPCs in the treatment of the disease

Restorative Mechanism of Neural Progenitor Cells Overexpressing Arginine Decarboxylase Genes Following Ischemic Injury

Cell replacement therapy using neural progenitor cells (NPCs) following ischemic stroke is a promising potential therapeutic strategy, but lacks efficacy for human central nervous system (CNS) therapeutics. In a previous in vitro study, we reported that the overexpression of human arginine decarboxylase (ADC) genes by a retroviral plasmid vector promoted the neuronal differentiation of mouse NPCs. In the present study, we focused on the cellular mechanism underlying cell proliferation and differentiation following ischemic injury, and the therapeutic feasibility of NPCs overexpressing ADC genes (ADC-NPCs) following ischemic stroke. To mimic cerebral ischemia in vitro , we subjected the NPCs to oxygen-glucose deprivation (OGD). The overexpressing ADC-NPCs were differentiated by neural lineage, which was related to excessive intracellular calcium-mediated cell cycle arrest and phosphorylation in the ERK1/2, CREB, and STAT1 signaling cascade following ischemic injury. Moreover, the ADC-NPCs were able to resist mitochondrial membrane potential collapse in the increasingly excessive intracellular calcium environment. Subsequently, transplanted ADC-NPCs suppressed infarct volume, and promoted neural differentiation, synapse formation, and motor behavior performance in an in vivo tMCAO rat model. The results suggest that ADC-NPCs are potentially useful for cell replacement therapy following ischemic stroke.

Diffuse Intrinsic Pontine Gliomas Exhibit Cell Biological and Molecular Signatures of Fetal Hindbrain-Derived Neural Progenitor Cells / 神经科学通报·英文版

Diffuse intrinsic pontine glioma (DIPG) is the main cause of brain tumor-related death among children. Until now, there is still a lack of effective therapy with prolonged overall survival for this disease. A typical strategy for preclinical cancer research is to find out the molecular differences between tumor tissue and para-tumor normal tissue, in order to identify potential therapeutic targets. Unfortunately, it is impossible to obtain normal tissue for DIPG because of the vital functions of the pons. Here we report the human fetal hindbrain-derived neural progenitor cells (pontine progenitor cells, PPCs) as normal control cells for DIPG. The PPCs not only harbored similar cell biological and molecular signatures as DIPG glioma stem cells, but also had the potential to be immortalized by the DIPG-specific mutation H3K27M in vitro. These findings provide researchers with a candidate normal control and a potential medicine carrier for preclinical research on DIPG.

Role of a 19S Proteasome Subunit- PSMD10(Gankyrin) in Neurogenesis of Human Neural Progenitor Cells

PSMD10(Gankyrin), a proteasome assembly chaperone, is a widely known oncoprotein which aspects many hall mark properties of cancer. However, except proteasome assembly chaperon function its role in normal cell function remains unknown. To address this issue, we induced PSMD10(Gankyrin) overexpression in HEK293 cells and the resultant large-scale changes in gene expression profile were analyzed. We constituted networks from microarray data of these differentially expressed genes and carried out extensive topological analyses. The overrecurring yet consistent theme that appeared throughout analysis using varied network metrics is that all genes and interactions identified as important would be involved in neurogenesis and neuronal development. Intrigued we tested the possibility that PSMD10(Gankyrin) may be strongly associated with cell fate decisions that commit neural stem cells to differentiate into neurons. Overexpression of PSMD10(Gankyrin) in human neural progenitor cells facilitated neuronal differentiation via β-catenin Ngn1 pathway. Here for the first time we provide preliminary and yet compelling experimental evidence for the involvement of a potential oncoprotein – PSMD10(Gankyrin), in neuronal differentiation.

T-Type Calcium Channels Are Required to Maintain Viability of Neural Progenitor Cells

T-type calcium channels are low voltage-activated calcium channels that evoke small and transient calcium currents. Recently, T-type calcium channels have been implicated in neurodevelopmental disorders such as autism spectrum disorder and neural tube defects. However, their function during embryonic development is largely unknown. Here, we investigated the function and expression of T-type calcium channels in embryonic neural progenitor cells (NPCs). First, we compared the expression of T-type calcium channel subtypes (CaV3.1, 3.2, and 3.3) in NPCs and differentiated neural cells (neurons and astrocytes). We detected all subtypes in neurons but not in astrocytes. In NPCs, CaV3.1 was the dominant subtype, whereas CaV3.2 was weakly expressed, and CaV3.3 was not detected. Next, we determined CaV3.1 expression levels in the cortex during early brain development. Expression levels of CaV3.1 in the embryonic period were transiently decreased during the perinatal period and increased at postnatal day 11. We then pharmacologically blocked T-type calcium channels to determine the effects in neuronal cells. The blockade of T-type calcium channels reduced cell viability, and induced apoptotic cell death in NPCs but not in differentiated astrocytes. Furthermore, blocking T-type calcium channels rapidly reduced AKT-phosphorylation (Ser473) and GSK3β-phosphorylation (Ser9). Our results suggest that T-type calcium channels play essential roles in maintaining NPC viability, and T-type calcium channel blockers are toxic to embryonic neural cells, and may potentially be responsible for neurodevelopmental disorders.

Effects of α-asarone on Proliferation and Differentiation of Neural Progenitor Cells / 체질인류학회지

This study investigated whether α-asarone could promote proliferation and differentiation of neural progenitor cells into the neuronal cell types in in vitro and ex vivo studies. For in vitro assay, neural progenitor cells were isolated from fetal cerebral cortex (E15) and checked cell proliferation rate and neural progenitor cell marker in neurospheres. Treatment of α-asarone, particularly at a concentration of 3 µM, promoted the proliferation of neural progenitor cells and effectively differentiated neural progenitor cells into neurons. For ex vivo assay, a hippocampi slice culture system from 7 day postnatal rat fetuses was used. Although slight tissue damage was observed in the hippocampus after the high concentration (100 µM) of α-asarone, however, α-asarone enhanced the proliferation of neural progenitor cells in dentate gyrus region and also effectively differentiated into neuroblast at concentration of 30 µM. Consequently, α-asarone promotes the proliferation of neural progenitor cells and effectively differentiates neural progenitor cells into neurons. Therefore, our results support the therapeutic benefits of α-asarone for treating neurodegenerative diseases.

Role of Notch Signaling Pathway in Neurogenesis in Central Nervous System (review) / 中国康复理论与实践

@#The Notch signaling pathway plays a pivotal role in the process of neurogenesis in central nervous system. It not only maintains the appropriate number and proportion of neurons and glial cells in the growth and development of embryo, but also regulates the injured neural stem/progenitor cells to differentiate into neurons/glial cells of the adult nervous system, promoting the repair of the nervous system.

Elimination of the geomagnetic field stimulates the proliferation of mouse neural progenitor and stem cells

Living organisms are exposed to the geomagnetic field (GMF) throughout their lifespan. Elimination of the GMF, resulting in a hypogeomagnetic field (HMF), leads to central nervous system dysfunction and abnormal development in animals. However, the cellular mechanisms underlying these effects have not been identified so far. Here, we show that exposure to an HMF (<200 nT), produced by a magnetic field shielding chamber, promotes the proliferation of neural progenitor/stem cells (NPCs/NSCs) from C57BL/6 mice. Following seven-day HMF-exposure, the primary neurospheres (NSs) were significantly larger in size, and twice more NPCs/NSCs were harvested from neonatal NSs, when compared to the GMF controls. The self-renewal capacity and multipotency of the NSs were maintained, as HMF-exposed NSs were positive for NSC markers (Nestin and Sox2), and could differentiate into neurons and astrocyte/glial cells and be passaged continuously. In addition, adult mice exposed to the HMF for one month were observed to have a greater number of proliferative cells in the subventricular zone. These findings indicate that continuous HMF-exposure increases the proliferation of NPCs/NSCs, in vitro and in vivo. HMF-disturbed NPCs/NSCs production probably affects brain development and function, which provides a novel clue for elucidating the cellular mechanisms of the bio-HMF response.

Dendritic cells differentiated from 129/svj ES-D3 embryonic stem cells prolong syngeneic neural progenitor cells survival in ischemic rat brain / 中国免疫学杂志

Objective:To study if embryonic stem cell derived dendritic cells(esDCs) could induce transplant tolerance to syngeneic neural progenitor cells ( NPCs) in ischemic rat brain.Methods:Neural progenitor cells ( NPCs) were differentiated from 129/svj pCX-eGFP ES-D3 embryonic stem cells and dendritic cells were directly differentiated from 129/svj ES-D3 respectively.All of SD rats were accepted MCAo surgery and subdivided in two groups based on pretreatment with or without esDCs through tail vein injection 1 week after MCAo.pCX-eGFP NPCs were then injected into the lateral ventricle of animals 2 weeks after MCAo.A proliferation assay of lymphocytes dissociated from cervical lymph nodes by MTT method,counting of the survival of the grafted cells, histological evaluation of CD4,CD8 and ED1 positive cells in brain and detection of mRNA level of IL-10 and IFN-γin ischemic lesions by reverse transcriptase-polymerase chain reaction(RT-PCR) were performed 2 weeks after graft (4 weeks after MCAo).Results:Pre-treatment with esDCs decreased CD4 positive cells infiltration (134.7 ±36.2 vs.198.8 ±59.6,P0.05).There was also no difference in lymphocytes proliferation (PI,1.245 ±0.211 vs.1.331 ±0.235) or mRNA expression level of IL-10 ( 1.147 ±0.260 vs.1.264 ±0.119 ) and IFN-γ( 1.697 ±0.273 vs.1.829 ±0.250 ) between two groups ( P>0.05).Conclusion:The results indicate that pretreatment with esDCs may prolong syngeneic NPCs survival though reducing CD4 positive cells reaction in ischemic striatum,which provides some evidence for the tolerogenic function of esDCs.However,there was lack of evidence for cytokine-dependent routine involving in this mode and further investigation was needed to make certain the cardinal principle.

Neurotrophin-3 Chitosan Scaffolds Induced Hippocampal Neural Network Formation after Traumatic Brain Injury in Adult Rats / 中国康复理论与实践

@#Objective To repair the traumatic brain injury in adult rats by inducing neural synapses formation with neurotrophin- 3 (NT-3) chitosan scaffolds. Methods 60 adult male Wistar rats were equally divided into lesion group, blank chitosan scaffolds group and NT-3 chitosan scaffolds group. The neural regeneration in the lesion area were observed through immunochemistry 3 days, 7 days, 14 days,28 days, 60 days after operation. Regenerated neural synapses involved the neural circuitry reconstruction in the lesion area were observed through neural tracing and immune electron microscopy 30 days and 60 days after operation. Results The nestin+, β-tubulin-Ⅲ+, microtubule associated protein 2 (MAP2)+ neural cells in hippocampal lesion area were significantly more in the NT-3 chitosan scaffolds group than in the other groups (P<0.01). Newborn neurons that express 5-bromouracil deoxyriboside (BrdU) and MAP2 were observed and formed synaptic connections in hippocampal damage zone in the NT-3 chitosan scaffolds group. Regenerated neural synapses involved the neural circuitry reconstruction in the lesion area. Conclusion NT-3 chitosan scaffolds activate the neural progenitor cells to proliferate and differentiate to mature neurons, which form neural synapses to involve the neural circuitry reconstruction.

Curcumin Stimulates Proliferation of Spinal Cord Neural Progenitor Cells via a Mitogen-Activated Protein Kinase Signaling Pathway

OBJECTIVE: The aims of our study are to evaluate the effect of curcumin on spinal cord neural progenitor cell (SC-NPC) proliferation and to clarify the mechanisms of mitogen-activated protein (MAP) kinase signaling pathways in SC-NPCs. METHODS: We established cultures of SC-NPCs, extracted from the spinal cord of Sprague-Dawley rats weighing 250 g to 350 g. We measured proliferation rates of SC-NPCs after curcumin treatment at different dosage. The immuno-blotting method was used to evaluate the MAP kinase signaling protein that contains extracellular signal-regulated kinases (ERKs), p38, c-Jun NH2-terminal kinases (JNKs) and beta-actin as the control group. RESULTS: Curcumin has a biphasic effect on SC-NPC proliferation. Lower dosage (0.1, 0.5, 1 microM) of curcumin increased SC-NPC proliferation. However, higher dosage decreased SC-NPC proliferation. Also, curcumin stimulates proliferation of SC-NPCs via the MAP kinase signaling pathway, especially involving the p-ERK and p-38 protein. The p-ERK protein and p38 protein levels varied depending on curcumin dosage (0.5 and 1 microM, p<0.05). CONCLUSION: Curcumin can stimulate proliferation of SC-NPCs via ERKs and the p38 signaling pathway in low concentrations.

The Effect of Agmatine on Expression of IL-1beta and TLX Which Promotes Neuronal Differentiation in Lipopolysaccharide-Treated Neural Progenitors

Differentiation of neural progenitor cells (NPCs) is important for protecting neural cells and brain tissue during inflammation. Interleukin-1 beta (IL-1beta) is the most common pro- inflammatory cytokine in brain inflammation, and increased IL-1beta levels can decrease the proliferation of NPCs. We aimed to investigate whether agmatine (Agm), a primary polyamine that protects neural cells, could trigger differentiation of NPCs by activating IL-1beta in vitro. The cortex of ICR mouse embryos (E14) was dissociated to culture NPCs. NPCs were stimulated by lipopolysaccharide (LPS). After 6 days, protein expression of stem cell markers and differentiation signal factors was confirmed by using western blot analysis. Also, immunocytochemistry was used to confirm the cell fate. Agm treatment activated NPC differentiation significantly more than in the control group, which was evident by the increased expression of a neuronal marker, MAP2, in the LPS-induced, Agm-treated group. Differentiation of LPS-induced, Agm-treated NPCs was regulated by the MAPK pathway and is thought to be related to IL-1beta activation and decreased expression of TLX, a transcription factor that regulates NPC differentiation. Our results reveal that Agm can promote NPC differentiation to neural stem cells by modulating IL-1beta expression under inflammatory condition, and they suggest that Agm may be a novel therapeutic strategy for neuroinflammatory diseases.

Neurogenesis in the brain / 西安交通大学学报(医学版)

Neurogenesis is sustained throughout adulthood in the mammalian brain due to the proliferation and differentiation of adult neural progenitor cells found in the subventricular zone of the lateral ventricles and subgranular zone of the dentate gyrus. This review covers recent findings that elucidate different aspects of regulation of neurogenesis, including proliferation, migration and differentiation into mature neurons and functional integration into the existing neural circuits. Furthermore, this review also discusses the effects of pathological conditions on adult neurogenesis in both rodent models and human patients as well as some of the potential problems or limitations in neurogenesis research, which may shed some light on developing novel research strategies for replacement treatment of neurological disorders.

Impact of venom nerve growth factor on neural progenitor cell proliferation and migration after cerebral ischemia/reperfusion injury in rats / 中国脑血管病杂志

Objective: To investigate the impact of venom nerve growth factor (vNGF) administered via lateral ventricle on neural progenitor cell proliferation and migration after cerebral ischemia/reperfusion injury in rats. Methods: Ninety healthy and clean male Wistar rats were randomly allocated into 2-day, 7-day, and 14-day groups. Then they were redivided into 5 subgroups at each time point: vNGF 25 U, vNGF 50 U, vNGF 100 U, control, and sham operation. The rat focal cerebral ischemia/reperfusion injury models of the control group and each vNGF subgroup were established. Corresponding dose of vNGF or isotonic saline was administered via the lateral ventricular cannula in all the subgroups according to the specified time points. Immunohistochemical method was used to detect the numbers of DCX positive neural precursor cells around the ischemic cortex and hippocampus CA3/Dentate gyrus in rats of each group. Results: Circled digit oneAfter administering vNGF via the lateral ventricle at each time point, the Longa's scores of the neurological function in all the vNGF subgroups were lower than those in the control group. There were statistical significances (P<0.01). Circled digit twoThe DCX-positive cells in the peri-ischemic cortex and hippocampus CA3/dentate gyrus showed the same change trend. The numbers of DCX positive cells in the 7-d subgroup was higher than those in the 2- and 14-d subgroups when the vNGF dose was the same. There were statistical significances (P < 0.01). Circled digit threeIn comparison of the subgroups with different vNGF doses at the same time points, the numbers of DCX positive cells in the vNGF 50 U subgroup was higher than those of vNGF 25 U and 100 U subgroups. There were statistical significances (P < 0.01). Circled digit fourThe numbers of DCX positive cells at each time point in the vNGF subgroups were significantly higher than those in the control group. There were statistical significances (P < 0.05). Conclusion: After administering vNGF via the lateral ventricle, it may increase the numbers of DCX positive neural precursor cells in the peri-ischemic cortex and hippocampus CA3/dentate gyrus after cerebral ischemia/reperfusion injury in rats.

Mechanism of cyclin-dependent inhibitor p27~(Kip1) in regulating the differentiation of immortalized human neural progenitor cells / 解剖学报

Objective To investigate whether there is any functional link between p27~(Kip1) function and all-trans retinoic acid (RA) in the control of neuronal differentiation of immortalized human neural progenitor cells (hSN12W-TERT cells). To investigate the mechanism by which p27~(Kip1) regulates the differentiation of immortalized human neural progenitor cells. Methods hSN12W-TERT cells were derived from the striatums of human embryos at 12 weeks gestation and cultured with serum-free medium in presence of EGF and bFGF. At the appropriated time, hSN12W-TERT cells were exposed to 1μmol/L RA for 3, 5, 7 days respectively. The experiment was repeated there times. Cell cycle analysis was performed by flow cytometry analysis (FACS). The expression of p27~(Kip1), p21~(cip1), cyclin-dependent kinase 2 (cdk2), p-cdk2 and S-phase kinase-associated protein 2 (skp2) in hSN12W-TERT cells before and after RA treatment cells were determined by using Western blotting analysis. Results FACS result showed that 77.25% of proliferating hSN12W-TERT cells were in the G1/G0-phase while 9.38% of cells in the S-phase. Following RA treatment, cell growth was arrested, and 85.68% of cells accumulated in G1/G0-phase while 8.57% of cells in the S-phase. Western blotting analysis demonstrated that the levels of p27~(Kip1) in the hSN12W-TERT cells increased following 3 days' treatment with RA compared with those of normal untreated cells, with a peak at 5 days (P<0.05). The similar results were acquired both in nuclear proteins and in cytoplasm proteins of hSN12W-TERT cells. The expression level of p21~(cip1) decreased in response to RA treatment. RA did not affect the expression of cdk2, but the expression of p-cdk2, which represented the activity of cdk2, was markedly decreased in response to RA treatment. Skp2, which was required for the ubiquitin-mediated degradation of p27~(Kip1), was detected in proliferating hSN12W-TERT cells. The expression of skp2 reduced dramatically in response to RA treatment in a time-dependent manner.Conclusion There is a functional link between RA and p27~(Kip1) function in the control of neuronal differentiation in hSN12W-TERT cells. P27~(Kip1) plays a key role during neuronal differentiation. Moreover, high levels of p27~(Kip1) are associated with its degradation inhibiting through reducing proteasome-dependent proteolysis.

Hepatocyte growth factor enhances the neural differentiation from human embryonic stem cells / 中国病理生理杂志

AIM: To investigate the possibility that hepatocyte growth factor (HGF) directly induces differentiation of human embryonic stem cells (hESCs) into neural progenitors (NPs). METHODS: hESCs colonies were induced to form the embryoid body (EB). Four-day-old EBs were randomly divided into 4 groups: control group (EBs were cultured in neural induction medium);G5 supplement group (EBs were cultured in neural induction medium supplied with G5 supplement);HGF group (EBs were cultured in neural induction medium supplied with 10 mg/L HGF), and HGF+G5 group (EBs were cultured in neural induction medium supplied with 10 mg/L HGF and G5 supplement). After induced in suspension system for 7 days, EBs with various treatments were cultured in poly-D-lysine/laminin-coated plates for 7-10 days for selection of NPs. NPs were gathered by 0.3 g/L dispase treatment and characterized by immunofluorescence staining. The percentages of the nestin+ cells in NPs in various groups were detected by fluorescent activated cell sorter (FACS). The multipotency of NPs was determined by immunofluorescence staining after the NPs were cultured without G5 and HGF for 7 days. The expression of region markers of neural progenitors treated with sonic hedgehog (Shh) protein (one of the neural inductive signals), was detected by RT-PCR. RESULTS: HGF+G5 supplement induced hESCs differentiation into neural progenitors. Immunofluorescence staining indicated that NPs differentiated from hESCs expressed NP markers including nestin, Pax6 and musashi-1. FACS data showed that the proportion of nestin positive cells in HGF+G5 supplement group (87.3%±3.9%) was the highest in all treatment groups. The time of HGF and G5 supplement treatment was important to differentiate into NPs, the maximal effect was observed at 7th day. After treated with Shh, the expression of ventral forebrain/hindbrain marker genes (Nkk2.1, and Nkk2.2) and hindbrain progenitor marker gene Gbx2 in NPs were upregulated, while the forebrain progenitor marker genes Otx2 and Bf1 were downregulated. CONCLUSION: The neural induction system containing HGF and G5 supplement effectively induces the differentiation of hESCs into NPs, which might be a potent model for investigating the mechanism of neural development and differentiation.

Efficient Derivation of Mesenchymal Stem Cells and Neural Precursor Cells From Human Embryonic Stem Cells Through Teratoma Formation / 生物化学与生物物理进展

Many somatic cell typos were obtained by in vitro differentiation or teratoma formation of human embryonic stem ceLls (hESCs). However, it is unclear whether specific cell types can be obtained from hESCs-derived teratoma. It was reported that many kinds of cells, including neural progetfitor/precursor cells (NPCs) and mesenchymal stem cells (MSCs) were isolated efficiently from the teratoma of hESCs through in vitro selection. The teratoma-derived NPCs and MSCs showed specific characteristics of molecular markers similar to the primary NPCs and MSCs. Moreover, these teratoma-induced NPCs and MSCs can be further induced to differentiate into neurons, astrocytes, or adipose and bone cells, reflecting their inherent multi-potencies. Given that teratoma normally contains a mixture of ectoderm, mesodenn, and endoderm lineage cells at different differentiation stage, it was suggested that hESCs-derived teratoma could be an alternative source to generate a variety of uncommitted progenitor cells or terminally differentiated somatic cells, which may be otherwise difficult to obtain through direct in vitro differentiation.