Acylhydrazone Derivative A5 Promotes Neurogenesis by Up-Regulating Neurogenesis-Related Genes and Inhibiting Cell-Cycle Progression in Neural Stem/Progenitor Cells.

Adult neurogenesis involves the generation of functional neurons from neural progenitor cells, which have the potential to complement and restore damaged neurons and neural circuits. Therefore, the development of drugs that stimulate neurogenesis represents a promising strategy in stem cell therapy and neural regeneration, greatly facilitating the reconstruction of neural circuits in cases of neurodegeneration and brain injury. Our study reveals that compound A5, previously designed and synthesized by our team, exhibits remarkable neuritogenic activities, effectively inducing neurogenesis in neural stem/progenitor cells (NSPCs). Subsequently, transcriptome analysis using high-throughput Illumina RNA-seq technology was performed to further elucidate the underlying molecular mechanisms by which Compound A5 promotes neurogenesis. Notably, comparative transcriptome analysis showed that the up-regulated genes were mainly associated with neurogenesis, and the down-regulated genes were mainly concerned with cell cycle progression. Furthermore, we confirmed that Compound A5 significantly affected the expression of transcription factors related to neurogenesis and cell cycle regulatory proteins. Collectively, these findings identify a new compound with neurogenic activity and may provide insights into drug discovery for neural repair and regeneration.

Poria cocos (Schw.) Wolf, a Traditional Chinese Edible Medicinal Herb, Promotes Neuronal Differentiation, and the Morphological Maturation of Newborn Neurons in Neural Stem/Progenitor Cells.

Neurogenesis in the adult brain comprises the entire set of events of neuronal development. It begins with the division of precursor cells to form a mature, integrated, and functioning neuronal network. Adult neurogenesis is believed to play an important role in animals' cognitive abilities, including learning and memory. In the present study, significant neuronal differentiation-promoting activity of 80% (v/v) ethanol extract of P. cocos (EEPC) was found in Neuro-2a cells and mouse cortical neural stem/progenitor cells (NSPCs). Subsequently, a total of 97 compounds in EEPC were identified by UHPLC-Q-Exactive-MS/MS. Among them, four major compounds-Adenosine; Choline; Ethyl palmitoleate; and L-(-)-arabinitol-were further studied for their neuronal differentiation-promoting activity. Of which, choline has the most significant neuronal differentiation-promoting activity, indicating that choline, as the main bioactive compound in P. cocos, may have a positive effect on learning and memory functions. Compared with similar research literature, this is the first time that the neuronal differentiation-promoting effects of P. cocos extract have been studied.

Lycorine inhibits the proliferation of neuroblastoma neuro-2a cells by inducing G2/M phase cell cycle arrest and apoptosis.

Lycorine, a benzylphenanthridine-type alkaloid extracted form Amarillidaceae genera, exhibits an efficacy against various types of cancer. Nonetheless, the impact of lycorine treatment on neuroblastoma has not yet been investigated. Here we utilized a combinatorial strategy to explore and to understand the effect of lycorine on neuroblastoma Neuro-2a cells. Our results indicated that lycorine inhibits the Neuro-2a cells proliferation by promoting cell apoptosis. In addition, wound healing assay revealed that lycorine inhibits the Neuo-2a cells migration. Comparative transcriptome analysis showed that lycorine has the potential to affect cycle pathway. Flow cytometry analysis confirmed that lycorine arrested the Neuro-2a cell cycle at G2/M phase. Furthermore, we detected that the protein expression of Cyclin A, Cyclin B1 and Cyclin E were decreased, whereas protein of p53, Tgfß3, Gadd45ß, Gadd45γ, p21 and p27 were increased after treatment with lycorine. Collectively, we propose that lycorine might be a valuable candidate therapeutic agent in combating neuroblastoma.

Regulation of neural stem cell self-renewal, proliferation and differentiation by the RhoA guanine nucleotide exchange factor Arhgef 1.

The role of the Arhgef1 as a RhoA-specific guanine nucleotide exchange factor has been widely investigated in the immune system. Our previous findings reveal that Arhgef 1 is highly expressed in neural stem cells (NSCs) and controls the process of neurite formation. However, the functional role of Arhgef 1 in NSCs remains poorly understood. In order to investigate the role of Arhgef 1 in NSCs, Arhgef 1 expression in NSCs was reduced by using lentivirus-mediated short hairpin RNA interference. Our results indicate that down-regulated expression of Arhgef 1 reduced the self-renewal, proliferation capacity of NSCs and affect cell fate determination. In addition, the comparative transcriptome analysis from RNA-seq data determines the mechanisms of deficits in Arhgef 1 knockdown NSCs. Altogether, our present studies show that Arhgef 1 down-regulation leads to interruption of the cell cycle procession. The importance of Arhgef 1 for regulating self-renewal, proliferation and differentiation in NSCs is reported for the first time.

The effect of cofilin 1 expression and phosphorylation dynamics on cell fate determination and neuron maturation in neural stem cells.

Previous studies showed that neural stem cells (NSCs) have an ability to differentiate into neurons, astrocytes and oligodendrocytes. However, the mechanisms that govern the fate of neural stem cell determination have not yet been fully clarified. In this study, we demonstrated that expression and activation of cofilin 1, a F-actin depolymerizing factor, are significantly changed during the development of brain, cortex or NSCs. Using Neuro-2a cells as a model, we found that overexpression of cofilin 1 significantly inhibit the cell differentiation and neurite outgrowth, while inhibition of intracellular cofilin 1 phosphorylation was significantly promoted. In cultured NSCs, we observed that cofilin 1 reduced the proportion of neurons derived from NSC due to inhibition of the phosphorylation, while the morphological maturation of neurons was promoted. Together, our findings revealed that cofilin 1 plays dynamic regulatory role on NSC cell fate determination and enhance neuronal maturation through regulating its activity and expression.

Synthesis of some new acylhydrazone compounds containing the 1,2,4-triazole structure and their neuritogenic activities in Neuro-2a cells.

In the present study, a novel series of acylhydrazone compounds (A0-A10) with the structure of 1,2,4-triazole have been designed and synthesized. In addition, all the synthesized compounds have been evaluated for neuritogenic activity in mouse neuroblastoma (Neuro-2a) cells. Notably, we found that one of these 11 acylhydrazone compounds, compound A5 (2-(4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazol-3-ylthio)-N'-(2-hydroxybenzylidene)-acetohydrazide) displays excellent neuritogenic activity. Moreover, our present study revealed that compound A5 had the ability to induce neurite outgrowth through the PI3K/Akt and MEK-ERK signaling pathway in Neuro-2a cells. These findings suggest that compound A5 might exert neuritogenic effects and thus may be useful for the treatment of neural repair and regeneration.

mTOR Signaling Upregulates CDC6 via Suppressing miR-3178 and Promotes the Loading of DNA Replication Helicase.

mTOR signaling pathway is deregulated in most cancers and uncontrolled cell cycle progression is a hallmark of cancer cell. However, the precise molecular mechanisms of the regulation of DNA replication and chromatin metabolism by mTOR signaling are largely unknown. We herein report that mTOR signaling promotes the loading of MCM2-7 helicase onto chromatin and upregulates DNA replication licensing factor CDC6. Pharmacological inhibition of mTOR kinase resulted in CHK1 checkpoint activation and decreased MCM2-7 replication helicase and PCNA associated with chromatins. Further pharmacological and genetic studies demonstrated CDC6 is positively controlled by mTORC1-S6K1 and mTORC2 signaling. miRNA screening revealed mTOR signaling suppresses miR-3178 thereby upregulating CDC6. Analysis of TCGA data found that CDC6 is overexpressed in most cancers and associates with the poor survival of cancer patients. Our findings suggest that mTOR signaling may control DNA replication origin licensing and replisome stability thereby cell cycle progression through CDC6 regulation.

Arhgef1 is expressed in cortical neural progenitor cells and regulates neurite outgrowth of newly differentiated neurons.

Neurite outgrowth is crucial for the maturation of neurons and the establishment of anatomical connections during development of the nervous system. We report here that Arhgef1, a RhoA guanine nucleotide exchange factor previously found expressed in the early stages of neuronal development to regulate neurite outgrowth, is also highly expressed in cortical neural progenitor cells (NPCs). To better dissect its role in NPCs, we knocked down Arhgef1 expression in these cells and induced differentiated of them into neurons. Notably, silencing of Arhgef1 markedly enhanced neurite outgrowth in neurons derived from NPCs. Furthermore, we showed that Arhgef1 silencing inhibited the activity of RhoA, and pharmacological blockade of RhoA activity promoted neurite outgrowth in NPC-derived neurons. These findings reveal that Arhgef1 controls the process of neurite formation in newborn cortical neurons derived from NPCs.

Arhgef1 negatively regulates neurite outgrowth through activation of RhoA signaling pathways.

Neurite outgrowth is essential for the establishment of functional neuronal connections during brain development. This study identifies that Arhgef1 is predominantly expressed in early neuronal developmental stages and negatively regulates neurite outgrowth. Knockdown of Arhgef1 in either Neuro-2a cells or primary cortical neurons leads to excess growth of neurites, whereas overexpression of Arhgef1 prominently restricts neurite formation. Arhgef1 strongly activates RhoA activity while concomitantly inhibits Rac1 and Cdc42 activities. Pharmacological blockade of RhoA activity restores normal neurite outgrowth in Arhgef1-overexpressed neurons. Importantly, Arhgef1 promotes F-actin polymerization in neurons, probably through inhibiting the activity of the actin-depolymerizing factor cofilin. Collectively, these findings reveal that Arhgef1 functions as a negative regulator of neurite outgrowth through regulating RhoA-cofilin pathway and actin dynamics.

Regulating Rac in the nervous system: molecular function and disease implication of Rac GEFs and GAPs.

Rho family GTPases, including RhoA, Rac1, and Cdc42 as the most studied members, are master regulators of actin cytoskeletal organization. Rho GTPases control various aspects of the nervous system and are associated with a number of neuropsychiatric and neurodegenerative diseases. The activity of Rho GTPases is controlled by two families of regulators, guanine nucleotide exchange factors (GEFs) as the activators and GTPase-activating proteins (GAPs) as the inhibitors. Through coordinated regulation by GEFs and GAPs, Rho GTPases act as converging signaling molecules that convey different upstream signals in the nervous system. So far, more than 70 members of either GEFs or GAPs of Rho GTPases have been identified in mammals, but only a small subset of them have well-known functions. Thus, characterization of important GEFs and GAPs in the nervous system is crucial for the understanding of spatiotemporal dynamics of Rho GTPase activity in different neuronal functions. In this review, we summarize the current understanding of GEFs and GAPs for Rac1, with emphasis on the molecular function and disease implication of these regulators in the nervous system.

Adipose tissue deletion of Gpr116 impairs insulin sensitivity through modulation of adipose function.

G protein-coupled receptor 116 (GPR116) is a novel member of the G protein-coupled receptors and its function is largely unknown. To investigate the physiological function of GPR116 in vivo, we generated adipose tissue specific conditional Gpr116 knockout mice (CKO) and fed them on standard chow or high fat diets. Selective deletion of Gpr116 in adipose tissue caused a pronounced glucose intolerance and insulin resistance in mice, especially when challenged with a high fat diet. Biochemical analysis revealed a more severe hepatosteatosis in CKO mice. Additionally, we found that CKO mice showed a lowered concentration of circulating adiponectin and an increased level of serum resistin. Our study suggests that GPR116 may play a critical role in controlling adipocyte biology and systemic energy homeostasis.

[Effects of exogenous salicylic acid on protein expression level in Baphicacanthus cusia (Nees) Bremek leaves].

By using two-dimensional eletrophoresis method, this paper studied the protein expression level in Baphicacanthus cusia (Nees) Bremek leaves after sprayed with exogenous salicylic acid (SA). A total of significantly different 20 protein spots were obtained, among which, eight protein spots were indentified, being of ATP synthase, alpha tubulin, cell division protein, glyceraldehydephosphate dehydrogenase, and ACC oxidase, respectively. The expression abundance of all identified proteins was up-regulated, except for ACC oxidase which was down-regulated. Therefore, exogenous SA could affect the protein expression level in B. cusia leaves, and improve the plant resistance to environment stress and self-restoration capability.

[Proteomics of rice leaf and grain at late growth stage under different nitrogen fertilization levels].

Taking super-rice Liangyoupeijiu as test material, and by the method of two-dimensional gel electrophoresis (2-DE), this paper studied the changes in the leaf and grain proteomics of the variety at its late growth stage under different levels of nitrogen fertilization (1/2 times of normal nitrogen level, 20 mg x L(-1); normal nitrogen level, 40 mg x L(-1); 2 times of normal nitrogen level, 80 mg x L(-1)), with the biological functions of 16 leaf proteins, 9 inferior grain proteins, and 4 superior grain proteins identified and analyzed. Nitrogen fertilization could affect and regulate the plant photosynthesis via affecting the activation of photosynthesis-related enzymes and of CO2, the light system unit, and the constitution of electron transfer chain at the late growth stage of the variety. It could also promote the expression of the enzymes related to the energy synthesis and growth in inferior grains. High nitrogen fertilization level was not beneficial to the synthesis of starch in superior grain, but sufficient nitrogen supply was still important for the substance accumulation and metabolism. Therefore, rational nitrogen fertilization could increase the photosynthesis rate of flag leaves, enhance the source function, delay the functional early ageing, and promote the grain-filling at late growth stage.