Alpha-pinene promotes osteoblast differentiation and attenuates TNFα-induced inhibition of differentiation in MC3T3-E1 pre-osteoblasts

Alpha-pinene (α-pinene) is an organic compound, found in the oils of many species of coniferous trees, especially pine. α-Pinene reportedly has antioxidant and anti-inflammatory activities; however, its effects on osteoblasts are unknown. This study investigated the effects of α-pinene on osteoblast differentiation and tumour necrosis factor-alpha (TNFα)-induced inhibition of osteogenesis. Culture in control or osteogenic medium containing α-pinene increased osteogenic marker expression. Alkaline phosphatase staining and alizarin red S staining confirmed that α-pinene enhanced osteoblast differentiation. Also, α-pinene attenuated TNFα-induced inhibition of Smad1/5/9 phosphorylation and extracellular matrix mineralization. Taken together, our findings suggest that α-pinene enhances osteoblast differentiation and mineralization in MC3T3-E1 pre-osteoblasts.     

Pain versus discomfort—is differentiation clinically useful?

Functional dyspepsia is highly variable in its clinical presentation and multifactorial in its underlying causes. Since many of the symptoms included in the definition of dyspepsia are intuitively suggestive of different pathogenic mechanisms, it has been proposed that patients with functional dyspepsia be divided into distinct dyspepsia sub-groups according to symptom clusters. The goal was to classify patients more homogeneously for research purposes as well as to target treatment. However, recent epidemiological, pathophysiological, and clinical studies indicate that a priori definitions based on the presence/absence of symptoms or clusters of symptoms have no clinical utility due to the considerable overlap between symptoms, as well as the poor correlation between pathogenic factors and responses to treatment. Attention is now focused on identifying predominant symptoms. Recent studies suggest that the analysis of predominant symptoms, demographic features, and overlapping digestive syndromes can help to identify dyspepsia sub-groups with different underlying pathophysiological features and aid in selecting appropriate treatment. The utility of this approach has been demonstrated in gastro-oesophageal reflux disease, which can be reliably diagnosed and managed on the basis of the presence and severity of the predominant symptom, heartburn. It is likely that precise symptom definitions and history-taking will be of pivotal importance in management strategies for functional dyspepsia.     

Neuron differentiation and neuritogenesis stimulated by N-acetylcysteine （NAC）

Aim： To investigate the effect of N-acetylcysteine （NAC）, a potent antioxidant, on neuron differentiation of cultured mouse embryonic stem cells （ESCs） induced by retinoic acid （RA） in vitro. Superior cervical ganglion （SCG） neurons were used to study the effect of NAC on neuritogenesis.
Methods： Immunoblotting was performed to detect the expression of microtubule-associated protein 2 （MAP2）. MTT assays were used to determine cell viability. Cell death was estimated with trypan blue exclusion and Hoechst 33342 staining. Immunocytochemical analysis was carried out to identify neurons.
Results： We obtained a high percentage of MAP2-positive neurons derived from embryoid bodies （EBs） induced by RA by administering 1 mmol/L NAC at differentiation day O. On differentiation day 8, the expression of MAP2 protein was strongly upregulated in the presence of NAC. NAC promoted neuron differentiation of ES cells in a dose- and time-dependent manner. Notably, NAC suppressed cell death caused b＇y RA during neuron differentiation. In addition, neurite extension of SCG neurons was greatly stimulated in the presence of NAC.
Conclusion： These results show that NAC enhanced both neuron differentiation and neuritogenesis, suggesting that it may be used in the development of novel therapeutic approaches targeting neuron loss and neurite dystrophy in neurodegenerative diseases.     

Effect of TGF-β/Smad signaling pathway on lung myofibroblast differentiation

AIM: Myofibroblasts play important roles in the pathogenesis of lung fibrosis. Transforming growth factor (TGF)-beta 1 has been widely recognized as a key fibrogenic cytokine. The major signaling pathway of (TGF)-beta(1) is through cytoplasmic Smad proteins. Our study investigated the role of individual (TGF)-beta(1)/Smad signal proteins in mediating alpha-smooth muscle actin (alpha-SMA) gene expression, which is a well-known key marker of myofibroblast differentiation. METHODS: We transiently cotransfected alpha-SMA promoter-luciferase fusion plasmid (p895-Luc) and Smad expression plasmids and measured Luc activity in (TGF)-beta(1)-treated human fetal lung fibroblasts. We induced Smad3 knockout mice lung fibrosis by bleomycin. alpha-SMA protein expression was assessed by Western blotting. Collagen protein was analyzed by measuring hydroxyprolin. Myofibroblast morphology was assessed by immunohistochemistry. RESULTS: We found that the overexpression of Smad3, not Smad2 markedly increased (TGF)-beta(1)-induced alpha-SMA promoter activity and alpha-SMA protein expression in vitro, whereas the overexpression of dominant negative mutant Smad3 and Smad7 repressed (TGF)-beta(1)-induced alpha-SMA gene expression. Compared to wild-type mice, Smad3 knockout mice showed attenuated lung fibrosis after bleomycin treatment, manifested by lower collagen production and myofibroblast differentiation. CONCLUSION: Our study suggested (TGF)-beta(1)/Smad3 is a major pathway which regulated the myofibroblast differentiation. This result indicates a potential significance for future attempts of attenuating the progression of human lung fibrosis by the inhibition of the Smad3 cascade.     

Glycogen synthase kinase-3β regulates astrocytic differentiation of U87-MG human glioblastoma cells

Aim:

To evaluate the role of glycogen synthase kinase-3β (GSK-3β) in the induced differentiation of human glioblastoma cells.

Methods:

Cell proliferation was determined by bromodeoxyuridine (BrdU) incorporation assay. The protein level of p-GSK-3β, GSK-3β, glial fibrillary acidic protein (GFAP) and proliferating cell nuclear antigen (PCNA) were determined using Western blots. The overexpression of mutant GSK-3β was analyzed by immunocytochemistry.

Results:

The biotoxin cholera toxin is capable of inducing differentiation of U87-MG human glioblastoma cells, which is characterized by morphological changes to astrocytic phenotype, increase in differentiation marker protein GFAP and decrease in proliferation. GSK-3β activation is induced during this differentiation. Small interfering RNA against GSK-3β suppresses the induced-differentiation in U87-MG cells. Conversely, overexpression of a constitutively active form of human GSK-3β (pcDNA3-GSK-3β-S9A) mutant leads to differentiation of U87-MG cells.

Conclusion:

Our findings suggest that GSK-3β plays an important role in astrocytic differentiation of human glioblastoma cells and may be a novel therapeutic target in the malignant tumor.     

大鼠神经干细胞的分离培养和分化鉴定

目的建立神经干细胞分离、培养和分化鉴定技术。观察神经干细胞生长、增殖特点。方法利用无血清培养,从胚胎大鼠海马、纹状体等区分离神经干细胞,进行体外扩增培养、传代观察。采用荧光免疫细胞化学检测技术,观察鉴定神经干细胞及其分化结果。结果从胚胎大鼠海马、纹状体等区分离的细胞具有增殖能力,可进行传代培养,获得的细胞克隆中有巢蛋白(nestin)表达阳性细胞,显微镜下观察见典型的干细胞特征。分化为3种神经细胞类型:神经元、胶质细胞、少突胶质细胞。结论用上述方法分离培养的神经干细胞具有自我更新和增殖能力,通过鉴定确为神经干细胞,并经过分化鉴定确认。     

神经干细胞增殖分化的JAK/STAT与Notch信号通路串话机制

JAK／STAT通路参与细胞的增殖、分化和凋亡等过程,近年来的研究显示,其在胚胎发育、成年个体脑肿瘤、脑缺血及损伤后脑内神经干细胞增殖过程中发挥重要作用。Notch介导的信号通路广泛存在于所有已知动物细胞中,是调控神经干细胞增殖、分化的经典信号通路。两条通路形成一个整体网络调控着神经干细胞增殖分化,本文综述Notch通路与JAIL／STAT通路在神经干细胞增殖过程中各组分的相互联系,旨在从网络药理学角度为脑缺血后神经保护及调控神经干细胞增殖药物的开发提供基础理论支持。     

人胚胎神经干细胞体外培养及其增殖与分化的研究

目的 建立神经干细胞分离、培养及分化的鉴定技术，观察神经干细胞增殖、分化的特点。方法 从人胚胎海马区分离神经干细胞，采用无血清培养基，进行体外扩增培养、传代。采用免疫细胞化学法鉴定神经干细胞和分化的神经细胞；利用流式细胞仪和细胞生长曲线检测神经干细胞的增殖能力。结果 从人胚胎脑海马区分离的细胞具有增殖和多向分化潜能，可进行传代培养，获得的细胞团中大部分为nestin表达阳性细胞。贴壁分化后可以出现NSE、GFAP表达阳性的细胞。结论 用上述方法分离培养的细胞能表达nestin蛋白，具有自我更新和增殖能力，并具有向神经元、星形胶质细胞分化的潜能，具备神经干细胞的特征，可用于细胞移植等相关研究。     

Comprehensive regulation of traditional Chinese medicine on proliferation and differentiation of neural stem cells

Since the diccovery of neural stem cells(NSCs)in the embryonic and adult mammalian central nerous system,it provided novel ideas forneurogenesis as the potential of proliferation and differentiation of NSCs.One of the ways to promote the clinical application of neural stem cells(NSCs)is searching effective methods which regulate the proliferation and differentiation.This is also a problem urgently to be solved in medical field.Plenty of earlier studies have shown that traditional chinese medicine can promote the proliferation and differentiation of NSCs by regulating the related signaling pathway in vivo and in vitro.The reports of Chinese and foreign literatures on regulating the proliferation and differentiation of neural stem cells in recent ten years and their target and signaling pathways is analyzed in this review.The traditional chinese medicine regulate proliferation and differentiation of NSCs by the signaling pathways of Notch,PI3K/Akt,Wnt/β-catenin,and GFs.And,those signaling pathways have cross-talk in the regulation progress.Moreover,some traditional Chinese medicine,such as astragalus,has a variety of active ingredients to regulate proliferation and differentiation of NSCs through different signaling pathways.However,to accelerate the clinical application of neural stem cells,the studies aboutthe proliferation and differentiation of NSCs and Chinese medicine should be further deepened,the mechanism of multiple targets and the comprehensive regulation function of traditional Chinese medicine should be clarified.     

Embryonic stem cell lines for regenerative therapy and pharmaceutical research

The establishment of human embryonic stem (ES) cell lines has brought great potential and expectations for regenerative medicine and pharmaceutical research, because many types of human cells could be produced by their unlimited growth and differentiation in culture. Primate and human ES cell lines have been established from blastocysts of monkey and surplus human blastocysts from fertility clinics. They showed several differences compared to mouse ES cells, including a tendency to produce the trophectoderm lineage and a different expression pattern of surface antigens. This may reflect species-specific differences, or these primate ES cells could represent earlier stages of development than mouse ES cells. Also, they show no response to the LIF and gp130 signals, which are widely used to repress spontaneous differentiation of mouse ES cell colonies. We have established several ES cell lines from blastocysts of the cynomolgus monkey. They can be maintained in culture as stem cell colonies, and they produce several differentiated cell types in culture. When such ES cells were transplanted into SCID mice, they produced teratomas containing many differentiated tissues.     

Non-dioxin-like polychlorinated biphenyls interfere with neuronal differentiation of embryonic neural stem cells

Developmental exposure to food contaminants, such as polychlorinated biphenyls (PCBs), has been considered as a possible cause of neurodevelopmental disorders. We have investigated the effects of noncytotoxic concentrations of PCBs 153 and 180 on spontaneous differentiation of rat embryonic neural stem cells (NSCs). Upon removal of basic fibroblast growth factor to induce spontaneous differentiation, cells were exposed to 100 nM of the selected PCBs for 48 h and analyzed after 5 days. Both PCBs 153 and 180 induced a significant increase in the number of neurite-bearing Tuj1-positive cells with a concomitant decrease in proliferating cells, as detected by FUCCI transfection and EdU staining. Measurements of spontaneous Ca2? oscillations showed a decreased number of cells with Ca2? activity after PCB exposure, further confirming the increase in neuronal cells. Conversely, exposure to methylmercury (MeHg), which we evaluated in parallel, led to an increased number of cells with Ca2? activity, in agreement with the previously observed inhibition of neuronal differentiation. Analysis with quantitative PCR of the Notch pathway revealed that PCBs have a repressive action on Notch signaling, whereas MeHg activates it. Altogether, the data indicate that nanomolar concentrations of the selected non-dioxin-like PCBs and MeHg interfere in opposite directions with neuronal spontaneous differentiation of NSCs through Notch signaling. Combined exposures to PCBs and MeHg resulted in an induction of apoptosis and an antagonistic interaction on spontaneous neuronal differentiation. NSCs are further proven to be a valuable in vitro model to identify potential developmental neurotoxicants.     

Glutamate as a modulator of embryonic and adult neurogenesis

It has been widely accepted that neurogenesis continues throughout life. Neural stem cells can be found in the ventricular zone of the embryonic and in restricted regions of the adult central nervous system, including subventricular and subgranular zones of the hippocampal dentate gyrus. The network of signaling mechanisms determining whether neural stem cells remain in a proliferative state or differentiate is only partly discovered. Recent advances indicate that glutamate (Glu), the predominant excitatory neurotransmitter in mature neurons, can influence immature neural cell proliferation and differentiation, as well. Despite many similarities, Glu actions on neurogenesis in the developing and adult brain show distinct differences and are far from being clear. Due to alterations of Glu transport mechanisms, extracellular Glu level is high in the embryonic CNS. Glu acts non-synaptically on dividing progenitors either by directly activating ionotropic and/or metabotropic Glu receptors or can influence other cells which are located in the vicinity of proliferating cells and produce molecules regulating neural precursor cell proliferation by other mechanisms. Due to the complexity of signaling pathways and to regional differences in neural precursors, Glu can influence proliferation and neuronal commitment as well, and acts as a positive regulator of neurogenesis. Brain injuries like ischemia, epilepsy or stress lead to severe neuronal death and additionally, influence neurogenesis, as well. Glu homeostasis is altered under these pathological circumstances, implying that therapeutic treatments mediating Glu signaling might be useful to increase neuronal replacement after cell loss in the brain.     

Nuclear receptors as targets for drug development: the role of nuclear receptors during neural stem cell proliferation and differentiation

The fate of stem cells, such as neural stem cells and hematopoietic stem cells, depends on strictly regulated signaling events including activation of nuclear receptors, resulting in subsequent gene induction. Recently, we demonstrated that PPARgamma, a ligand-activated nuclear receptor, plays an important role in regulating the proliferation and differentiation of murine neural stem cell (NSC). NSC prepared from heterozygous PPARgamma-deficient mouse exhibited a slower growth rate compared with that of wild-type mouse, which was also demonstrated in PPARgamma-knockdown NSC that was generated by the lentiviral-vector-mediated RNA interference approach. These studies have important implications for understanding central nervous system functions and developing a therapy for neurodegenerative disorders. In this review, recent findings on stem cell biology, especially focusing on nuclear receptors in NSCs, including our current study, will be discussed.