Wnt3a induces the expression of acetylcholinesterase during osteoblast differentiation via the Runx2 transcription factor.

Acetylcholinesterase (AChE) hydrolyzes acetylcholine to terminate cholinergic transmission in neurons. Apart from this AChE activity, emerging evidence suggests that AChE could also function in other, non-neuronal cells. For instance, in bone, AChE exists as a proline-rich membrane anchor (PRiMA)-linked globular form in osteoblasts, in which it is proposed to play a noncholinergic role in differentiation. However, this hypothesis is untested. Here, we found that in cultured rat osteoblasts, AChE expression was increased in parallel with osteoblastic differentiation. Because several lines of evidence indicate that AChE activity in osteoblast could be triggered by Wnt/ß-catenin signaling, we added recombinant human Wnt3a to cultured osteoblasts and found that this addition induced expression of the ACHE gene and protein product. This Wnt3a-induced AChE expression was blocked by the Wnt-signaling inhibitor Dickkopf protein-1 (DKK-1). We hypothesized that the Runt-related transcription factor 2 (Runx2), a downstream transcription factor in Wnt/ß-catenin signaling, is involved in AChE regulation in osteoblasts, confirmed by the identification of a Runx2-binding site in the ACHE gene promoter, further corroborated by ChIP. Of note, Runx2 overexpression in osteoblasts induced AChE expression and activity of the ACHE promoter tagged with the luciferase gene. Moreover, deletion of the Runx2-binding site in the ACHE promoter reduced its activity during osteoblastic differentiation, and addition of 5-azacytidine and trichostatin A to differentiating osteoblasts affected AChE expression, suggesting epigenetic regulation of the ACHE gene. We conclude that AChE plays a role in osteoblastic differentiation and is regulated by both Wnt3a and Runx2.

Erythropoietin regulates the expression of dimeric form of acetylcholinesterase during differentiation of erythroblast.

Acetylcholinesterase (AChE; EC 3.1.1.7) is known to hydrolyze acetylcholine at cholinergic synapses. In mammalian erythrocyte, AChE exists as a dimer (G2 ) and is proposed to play role in erythropoiesis. To reveal the regulation of AChE during differentiation of erythroblast, erythroblast-like cells (TF-1) were induced to differentiate by application of erythropoietin (EPO). The expression of AChE was increased in parallel to the stages of differentiation. Application of EPO in cultured TF-1 cells induced transcriptional activity of ACHE gene, as well as its protein product. This EPO-induced event was in parallel with erythrocytic proteins, for example, α- and ß-globins. The EPO-induced AChE expression was mediated by phosphorylations of Akt and GATA-1; because the application of Akt kinase inhibitor blocked the gene activation. Erythroid transcription factor also known as GATA-1, a downstream transcription factor of EPO signaling, was proposed here to account for regulation of AChE in TF-1 cell. A binding sequence of GATA-1 was identified in ACHE gene promoter, which was further confirmed by chromatin immunoprecipitation (ChIP) assay. Over-expression of GATA-1 in TF-1 cultures induced AChE expression, as well as activity of ACHE promoter tagged with luciferase gene (pAChE-Luc). The deletion of GATA-1 sequence on the ACHE promoter, pAChEΔGATA-1 -Luc, reduced the promoter activity during erythroblastic differentiation. On the contrary, the knock-down of AChE in TF-1 cultures could lead to a reduction in EPO-induced expression of erythrocytic proteins. These findings indicated specific regulation of AChE during maturation of erythroblast, which provided an insight into elucidating possible mechanisms in regulating erythropoiesis.

Badiranji Buya Keli, a Traditional Uyghur Medicine, Induces Vasodilation in Rat Artery: Signaling Mediated by Nitric Oxide Production in Endothelial Cells.

Badiranji Buya Keli (BBK) is a traditional Uyghur medicine derived from Dracocephalum Moldavica Herba (DMH, the aerial part of Dracocephalum moldavica L.). BBK has been widely used in treating cardiovascular and cerebrovascular diseases. Here, the quality control of BBK was established by using HPLC analysis of rosmarinic acid and tilianin. After chemical standardization, the biological effects of BBK was tested. First, BBK inhibited platelet aggregation of rabbit plasma. Second, BBK induced vasodilation in rat aortic ring, and this effect was partially mediated by nitric oxide (NO) production in endothelial cells. Third, BBK induced NO production in cultured human umbilical vein endothelial cells (HUVECs). In HUVECs, the phosphorylation of endothelial NO synthase (eNOS) was markedly increased after application of BBK. Pre-treatment with the eNOS blocker N(ω) -nitro-l-arginine methyl ester hydrochloride could abolish BBK-induced NO production and eNOS phosphorylation. Taken together, these results suggest that BBK could exert beneficial effects in cardiovascular system, which may provide parts of molecular explanation to account for its traditional usage in Uyghur medicine.

Ferulic acid enhances the chemical and biological properties of astragali radix: a stimulator for danggui buxue tang, an ancient Chinese herbal decoction.

Danggui buxue tang, an ancient formula composed of astragali radix and Angelicae sinensis radix, has been used for treating menopausal irregularity in women for more than 800 years in China. In danggui buxue tang, the complete functions of astragali radix require the assistance of Angelicae sinensis radix, and both herbs have to work harmoniously in order to achieve the maximal therapeutic purposes. In order to analyze the relationship of the two herbs, the role of ferulic acid, a major chemical within Angelicae sinensis radix, in chemical and biological properties of astragali radix was determined. Using ferulic acid in the extraction of astragali radix, the amounts of astragaloside IV, calycosin, and formononetin were increased in the final extract; however, the astragali radix polysaccharide showed a minor increase. The chemical-enriched astragali radix extract showed robust induction in osteogenic and estrogenic activities in cultured osteosarcoma MG-63 and breast MCF-7 cells. However, ferulic acid itself did not show such biological responses. The current results strongly suggest that Angelicae sinensis radix-derived ferulic acid is a positive regulator for danggui buxue tang, which enhanced the solubilities of active ingredients derived from astragali radix, and which therefore increased the biological efficacies of danggui buxue tang.

The extract of Ziziphus jujuba fruit (jujube) induces expression of erythropoietin via hypoxia-inducible factor-1α in cultured Hep3B cells.

The fruit of Ziziphus jujuba Mill., known as jujube or Chinese date, is commonly consumed as health supplement or herbal medicine worldwide. To study the beneficial role of jujube in enhancing hematopoietic function, we investigated its roles on the expression of erythropoietin in cultured Hep3B human hepatocellular carcinoma cells. Application of chemically standardized jujube water extract stimulated erythropoietin expression in a dose-dependent manner, with the highest response by ~ 100 % of increase. A plasmid containing hypoxia response element, a critical regulator for erythropoietin transcription, was transfected into Hep3B cells. Application of jujube water extract onto the transfected cells induced the transcriptional activity of the hypoxia response element. To account for its transcriptional activation, the expression of hypoxia-inducible factor-1α was increased after treatment with jujube water extract: the increase was in both mRNA and protein levels. These results confirmed the hematopoietic function of jujube in the regulation of erythropoietin expression in liver cells.

Flavonoids, derived from traditional Chinese medicines, show roles in the differentiation of neurons: possible targets in developing health food products.

Flavonoids, a family of phenolic compounds, are distributed in a variety of fruits, vegetables, tea, and wine. More importantly, many flavonoids are served as the active ingredients in traditional Chinese herbal medicines, which in general do not have side effects. Several lines of evidence support that flavonoids have impacts on many aspects of human health, including anti-tumor, anti-oxidation, and anti-inflammation. Recently, there is significant attention focused on the neuronal beneficial effects of flavonoids, including the promotion of nervous system development, neuroprotection against neurotoxin stress, as well as the promotion of memory, learning, and cognitive functions. Here, the activities of flavonoids on the development of nervous system are being summarized and discussed. The flavonoids from diverse herbal medicines have significant effects in different developmental stages of nervous systems, including neuronal stem cell differentiation, neurite outgrowth, and neuronal plasticity. These findings imply that flavonoids are potential candidates for the development of health supplements in preventing birth defects and neuronal diseases.

Flavonoids induce the expression of synaptic proteins, synaptotagmin, and postsynaptic density protein-95 in cultured rat cortical neuron.

Flavonoids, a family of phenolic compounds, are widely present in our daily diet and exist in traditional Chinese medicines, in which they act as the major active functional ingredients. Different lines of evidence indicate that flavonoids have positive impacts on human health. Here, different subclasses of flavonoids were analyzed for their inductive roles in promoting the expression of synaptic proteins, synaptotagmin, and post-synaptic density protein-95 in cultured rat cortical neurons. Among the screened 65 flavonoids, (-)-catechin, luteolin, and isorhamnetin, in micromolar concentration, were found to induce the expression of synaptic proteins in a dose-dependent manner: the induction values were from 2- to 8-fold that of the control. Similar results were revealed in the flavonoid-treated hippocampal neurons. The identification of these synapse-promoting flavonoids could be very useful in finding potential drugs, or food supplements, for treating various neurodegenerative diseases, including Alzheimer's disease and depression.

Importance of wine-treated Angelica Sinensis Radix in Si Wu Tang, a traditional herbal formula for treating women's ailments.

Si Wu Tang (Four Agents Decoction), a traditional Chinese decoction composed of Angelica Sinensis Radix, Chuanxiong Rhizoma, Paeoniae Radix Alba, and Rehmanniae Radix Praeparata in a ratio of 1 : 1 : 1 : 1, has been used to treat women's diseases for more than a thousand years. According to the original description of Si Wu Tang, Angelica Sinensis Radix should be treated with wine. However, the importance of this wine-treated Angelica Sinensis Radix in Si Wu Tang's function has not been identified. In this article, the chemical and biological properties of two decoctions processed in different ways (Si Wu Tang with crude Angelica Sinensis Radix and Si Wu Tang with wine-treated Angelica Sinensis Radix) were compared for examination. The herbal decoction Si Wu Tang prepared from wine-treated Angelica Sinensis Radix contained much different amounts of its active compounds. Compared with Si Wu Tang using crude Angelica Sinensis Radix, Si Wu Tang prepared from wine-treated Angelica Sinensis Radix had better biological responses. Therefore, these findings accentuate the functional importance of herbs treated with wine in the Chinese decoction.

Fo shou san, an ancient herbal decoction prepared from angelicae sinensis radix and chuanxiong rhizoma, induces erythropoietin expression: a signaling mediated by the reduced degradation of hypoxia-inducible factor in cultured liver cells.

Fo Shou San (FSS) is an ancient herbal decoction composed of Angelicae Sinensis Radix (ASR; Danggui) and Chuanxiong Rhizoma (CR; Chuanxiong) in a ratio of 3:2. FSS is mainly prescribed for patients having a deficiency of blood supply, and it indeed has been shown to stimulate the production of erythropoietin (EPO) in cultured cells. In order to reveal the mechanism of this FSS-induced EPO gene expression, the upstream regulatory cascade, via hypoxia-induced signaling, was revealed here in cultured hepatocellular carcinoma cell line Hep3B. The induction of EPO gene expression, triggered by FSS, was revealed in cultured hepatocytes by: (i) the increase of EPO mRNA; and (ii) the activation of the hypoxia response element (HRE), an upstream regulator of the EPO gene. The FSS-induced EPO gene expression was triggered by an increased expression of hypoxia-inducible factor-1 α (HIF-1 α) protein; however, the mRNA expression of HIF-1 α was not altered by the treatment of FSS. The increased HIF-1 α was a result of reduced protein degradation after the FSS treatment. The current results therefore provide one of the molecular mechanisms of this ancient herbal decoction for its hematopoietic function.

The extract of Rhodiolae Crenulatae Radix et Rhizoma induces the accumulation of HIF-1α via blocking the degradation pathway in cultured kidney fibroblasts.

Rhodiolae Crenulatae Radix et Rhizoma (Rhodiola), the root and rhizome of Rhodiola crenulata (Hook. f. et Thoms.) H. Ohba, has been used as a traditional Chinese medicine (TCM) to increase the body resistance against hypoxia in mountain sickness. The mechanism of this adaptogenic property deriving from Rhodiola, however, has not been revealed. Erythropoietin (EPO) is an erythrocyte-specific hematopoietic hormone that increases the production of red blood cells: this hormone is a crucial factor in regulating the body balance in responding to hypoxia. In cultured kidney fibroblasts (HEK293T), application of water extract deriving from Rhodiola induced the expression of EPO both in mRNA and protein levels. The activation of the Hypoxia Response Element (HRE) located on the promoter region of the EPO gene is one of the mechanisms accounting for transcriptional activation. In addition, the Rhodiola-induced EPO expression was triggered by an increase of hypoxia-inducible factor-1 α (HIF-1 α) protein, via the reduction of HIF-1 α degradation but not the induction of HIF-1 α mRNA. Moreover, the same EPO induction effect by Rhodiola was also observed in cultured liver cells since liver is another vital organ to provide EPO regulation apart from the kidney. These results therefore elucidate one of the molecular mechanisms of this herb in mediating the anti-hypoxia function.

Antihyperlipidemic effect of protodioscin, an active ingredient isolated from the rhizomes of Dioscorea nipponica.

Developing drugs against metabolic-related disorders, including obesity and hyperlipidemia, is of importance for human health. Here, a bioactive phytochemical, protodioscin, isolated from the rhizomes of Dioscorea nipponica (Rhizoma Dioscoreae Nipponicae), was identified for its anti-hyperlipidemic effect. In hyperlipidemic rats, the post-administration of protodioscin significantly reduced the time of blood coagulation. In addition, the blood levels of triglyceride, cholesterol, low-density and high-density lipoproteins were also changed accordingly. Taken together, this was the first report of an antihyperlipidemic effect of protodioscin. Its great availability in various vegetables and medicinal plants will be useful in developing health food supplement(s) and/or drug(s) against hyperlipidemia.

Can rhizoma chuanxiong replace radix Angelica sinensis in the traditional Chinese herbal decoction danggui buxue tang?

Herein, we test the hypothesis that a member of a formulated Chinese herbal decoction cannot be replaced by another herb. Danggui Buxue Tang (DBT) is being used as an example for illustration: this is a traditional decoction containing Radix Astragali (RA) and Radix Angelicae Sinensis (RAS) in a weight ratio of 5 to 1. Rhizoma Chuanxiong (RC) and RAS are two chemically very similar herbs but with a distinct function. Following the preparation method of DBT, a herbal decoction, namely Chuanxiong Buxue Tang (CBT), was created, which contained RA and RC in a weight ratio of 5 to 1. The two decoctions, DBT and CBT, were compared in parallel regarding their chemical and biological properties. In all the tested parameters, DBT showed superior properties, both chemically and biologically, to that of CBT. The current results reveal the uniqueness of Chinese herbal decoctions that require a well-defined formulation, which is indispensable for its specific composition.

Estrogenic and neuroprotective properties of scutellarin from Erigeron breviscapus: a drug against postmenopausal symptoms and Alzheimer's disease.

Besides the classical hormonal effect, estrogen possesses neuroprotective effects in the brain, which leads to the searching of novel treatments for neurodegenerative diseases such as Alzheimer's disease. Scutellarin is a major flavone derived from Herba Erigerontis, a Chinese medicine derived from Erigeron breviscapus, which has been shown here to possess both estrogenic and neuroprotective properties. Scutellarin showed the estrogenic effects by activating the estrogen responsive elements and phosphorylation of estrogen receptor alpha in cultured MCF-7 cells: the activation was in a dose-dependent manner. On the other hand, scutellarin inhibited the aggregation of beta-amyloid in vitro, and prevented the cell death mediated by beta-amyloid when applied to cultured neuronal PC12 cells. These results therefore suggested that Herba Erigerontis and its component scutellarin might have therapeutic effects against postmenopausal symptoms and Alzheimer's disease.

Myocyte enhancer factor 2 mediates acetylcholine-induced expression of acetylcholinesterase-associated collagen ColQ in cultured myotubes.

The collagenous protein (ColQ) characterizes the collagen-tailed forms of acetylcholinesterase (AChE) in vertebrate muscles. Two ColQ transcripts, ColQ-1 and ColQ-1a, driven by two distinct promoters are expressed differentially in mammalian slow- and fast-twitch muscles, respectively. Such expression patterns are determined by the contractile activity in different muscle fiber types. To reveal the regulatory role of muscular activity on ColQ expression, acetylcholine and nicotine were applied onto C2C12 muscle cells: the challenge increased the expression of ColQ-1/ColQ-1a mRNAs. The agonist challenge induced the phosphorylation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII). In parallel, over expression of an active mutant of CaMKII enhanced both ColQ-1/ColQ-1a mRNA levels in cultured C2C12 myotubes. Moreover, the over expression of myocyte enhancer factor 2 (MEF2), a downstream mediator of CaMKII, in the myotubes potentiated the CaMKII-induced ColQ expression. The current results reveal a signaling cascade that drives the expression profiles of ColQ in responding to activity challenge in cultured myotubes.

Transcriptional control of different subunits of AChE in muscles: signals triggered by the motor nerve-derived factors.

Acetylcholinesterase (AChE) is a highly polymorphic enzyme. Alternative splicing in the 3' region of the primary transcript generates different subunits that contain the same catalytic domain but with distinct carboxyl termini. In mammals, the AChE(R) variant produces a soluble monomer that is up-regulated in the brain during stress. The AChE(H) variant produces a GPI-anchored dimer that is mainly expressed in blood cells, while AChE(T) variant is largely predominant in the brain and muscle. AChE(T) subunits associate with a collagen tail subunit (ColQ) forming asymmetric AChE species (A(4), A(8), and A(12) AChE) in muscle, and also form amphiphilic tetramers associated with a proline-rich membrane anchor (PRiMA) as globular AChE (G(4) AChE) in brain and muscle. The formation of these AChE forms depends on the physiological status of the muscles, and on the innervating nerves. The motor nerves achieve this regulation by two distinct mechanisms: release of the trophic factor calcitonin gene-related peptide (CGRP) and nerve-evoked electrical activity, which differentially regulate the expression levels of AChE(T), PRiMA and ColQ via different downstream signaling cascades. The regulatory mechanisms provided by the nerve are important to account for the different expression patterns of AChE and associated proteins in fast- and slow-twitch muscles.

A Modified Chinese Herbal Decoction (Kai-Xin-San) Promotes NGF-Induced Neuronal Differentiation in PC12 Cells via Up-Regulating Trk A Signaling.

Kai-Xin-San (KXS), a Chinese herbal decoction, has been applied to medical care of depression for thousands of years. It is composed of two functional paired-herbs: Ginseng Radix et Rhizoma (GR)-Polygalae Radix (PR) and Acori Tatarinowii Rhizoma (ATR)-Poria (PO). The compatibility of the paired-herbs has been frequently changed to meet the criteria of syndrome differentiation and treatment variation. Currently, a modified KXS (namely KXS2012) was prepared by optimizing the combinations of GR-PR and ATR-PO: the new herbal formula was shown to be very effective in animal studies. However, the cellular mechanism of KXS2012 against depression has not been fully investigated. Here, the study on KXS2012-induced neuronal differentiation in cultured PC12 cells was analyzed. In PC12 cultures, single application of KXS2012 showed no effect on the neuronal differentiation, but which showed robust effects in potentiating nerve growth factor (NGF)-induced neurite outgrowth and neurofilament expression. The potentiating effect of KXS2012 was mediated through NGF receptor, tropomyosin receptor kinase (Trk) A: because the receptor expression and activity was markedly up-regulated in the presence of KXS2012, and the potentiating effect was blocked by k252a, an inhibitor of Trk A. Our current results in cell cultures fully support the therapeutic efficacy of KXS2012 against depression.

Flavonoids induce the expression of acetylcholinesterase in cultured osteoblasts.

Flavonoids, a group of natural compounds mainly derived from plants, are known to possess osteogenic effects in bone cells. Here, we aimed to test if flavonoid could induce a cholinergic enzyme, acetylcholinesterase (AChE), as well as bone differentiation. In cultured rat osteoblasts, twenty flavonoids, deriving from Chinese herbs and having known induction of alkaline phosphatase (ALP1) expression, were tested for its induction activity on AChE expression. Eleven flavonoids showed the induction, and five of them had robust activation of AChE expression, including baicalin, calycosin, genistin, hyperin and pratensein: the induction of AChE included the levels of mRNA, protein and enzymatic activity. Moreover, the flavonoid-induced AChE expression in cultured osteoblast was in proline-rich membrane anchor (PRiMA)-linked tetrameric globular form (G4) only. In parallel, the expression of PRiMA was also induced by the application of flavonoids. The flavonoid-induced AChE in the cultures was not affected by estrogen receptor blocker, ICI 182,780. Taken together, the induction of PRiMA-linked AChE in osteoblast should be independent to classical estrogen signaling pathway.

Expression of globular form acetylcholinesterase is not altered in P2Y1R knock-out mouse brain.

Adenosine 5'-triphosphate (ATP), a neurotransmitter and a neuromodulator, has been shown to be co-stored and co-released with acetylcholine (ACh) at the pre-synaptic vesicles in vertebrate neuromuscular junction (nmj). Several lines of studies demonstrated that binding of ATP to its corresponding P2Y1 receptors (P2Y1R) in muscle and neuron regulated the post-synaptic gene expressions. Indeed, the expression of acetylcholinesterase (AChE) in muscle was markedly decreased in P2Y1R-/- (P2Y1R knock-out) mice. In order to search for possible role of P2Y1R in cholinergic function of the brain, the expression of globular form AChE was determined in the brain of P2Y1R-/- mice. In contrast to that in muscle, the amounts of AChE activity, AChE catalytic subunit, structure subunit PRiMA and the amount of ACh, in the brain were not, significantly, altered, suggesting the role of P2Y1R in neuron could have different function as that in muscle. However, the expressions of a series of neuronal development markers, i.e. neurofilaments, were reduced in P2Y1R-/- mouse brain, indicating P2Y1R may be involved in neuronal development process.

2,3,7,8-Tetrachlorodibenzo-p-dioxin suppress AChE activity in NGF treated PC12 cells.

PC12 is a well studied cell model for neuronal differentiation. AChE is also considered as a marker for neuronal differentiation. In this study, we detected the change of AChE activity during the NGF induced differentiation of PC 12 cells, and targeted on the ratio of the activity of AChE on the cell surface, and found that NGF mainly increased the intracellular AChE activity. Dioxin is a kind of persistent organic pollutants which have extreme impact on human health and widely distributed all over the world. Recently, AChE was reported as a target of the toxicity of dioxin. Here we investigated the effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on AChE activity in the PC12 cells, and found that at the later stage of differentiation, TCDD could decrease the AChE activity. This down regulation might not related to transcriptional regulation.

Clivorine, an otonecine pyrrolizidine alkaloid from Ligularia species, impairs neuronal differentiation via NGF-induced signaling pathway in cultured PC12 cells.

BACKGROUND: Pyrrolizidine alkaloids (PAs) are commonly found in many plants including those used in medical therapeutics. The hepatotoxicities of PAs have been demonstrated both in vivo and in vitro; however, the neurotoxicities of PAs are rarely mentioned. PURPOSE: In this study, we aimed to investigate in vitro neurotoxicities of clivorine, one of the PAs found in various Ligularia species, in cultured PC12 cells. STUDY DESIGN: PC12 cell line was employed to first elucidate the neurotoxicity and the underlying mechanism of clivorine, including cell viability and morphology change, neuronal differentiation marker and signaling pathway. METHODS: PC12 cells were challenged with series concentrations of clivorine and/or nerve growth factor (NGF). The cell lysates were collected for MTT assay, trypan blue staining, immunocytofluorescent staining, qRT-PCR and western blotting. RESULTS: Clivorine inhibited cell proliferation and neuronal differentiation evidenced by MTT assay and dose-dependently reducing neurite outgrowth, respectively. In addition, clivorine decreased the level of mRNAs encoding for neuronal differentiation markers, e.g. neurofilaments and TrkA (NGF receptor). Furthermore, clivorine reduced the NGF-induced the phosphorylations of TrkA, protein kinase B and cAMP response element-binding protein in cultured PC12 cells. CONCLUSION: Taken together, our results suggest that clivorine might possess neurotoxicities in PC12 cells via down-regulating the NGF/TrkA/Akt signaling pathway. PAs not only damage the liver, but also possess neurotoxicities, which could possibly result in brain disorders, such as depression.