OBJECTIVETo investigate the role of glycogen synthase kinase 3β (GSK-3β) in the maturation and function of murine bone marrow-derived dendritic cells (BMDCs).

METHODSMature DCs (mDCs) induced by LPS were examined for GSK-3β phosphorylation level with Western blotting before and after LPS exposure. To explore the role of GSK-3β in maturation and function of DCs, we added SB216763, a selective inhibitor of GSK-3β, in the cell culture of immature DCs (iDCs), and examined CD40 and CD86 expressions in the cells by flow cytometry and the expression of IL-6, IL-12 and IL-10 mRNA by real-time PCR; the changes of the immunogenicity of the cells was evaluated by mixed lymphocyte reaction. The expression of GSK-3β and RelB was examined by Western blotting in DC2.4 cells transfected with a lentiviral vector over-expressing murine GSK-3β gene.

RESULTSLPS exposure significantly lowered GSK-3β activity in iDCs as demonstrated by increased Ser9 phosphorylation and reduced Tyr216 phosphorylation. GSK-3β inhibition induced DC maturation by increasing the expression of surface costimulatory molecules CD40 and CD86, lowered the expressions of IL-6 and IL-12 while enhanced the expression of IL-10 in iDCs, and impaired mixed lymphocyte reaction of the cells. In DC2.4 cells, lentivirus-mediated over-expression of GSK-3β obviously down-regulated the expression of RelB.

CONCLUSIONSGSK-3β is a crucial enzyme involved in the differentiation and maintenance of an immature phenotype of DCs. GSK-3β is constitutively active in iDCs to inhibit their spontaneous maturation. DCs become phenotypically mature after inhibition of GSK-3β, which also executes a proinflammatory task in DC activation. The reduction of RelB protein levels as a result of GSK-3β overexpression supports GSK-3β as a new target for inducing tolerogenic DCs.

Animals ; B7-2 Antigen ; metabolism ; CD40 Antigens ; metabolism ; Cell Differentiation ; Cells, Cultured ; Culture Media ; chemistry ; Dendritic Cells ; enzymology ; Glycogen Synthase Kinase 3 ; metabolism ; Glycogen Synthase Kinase 3 beta ; Indoles ; chemistry ; Interleukin-10 ; metabolism ; Interleukin-12 ; metabolism ; Interleukin-6 ; metabolism ; Lentivirus ; Lymphocyte Culture Test, Mixed ; Maleimides ; chemistry ; Mice ; Myeloid Cells ; enzymology ; Phosphorylation ; RNA, Messenger ; Real-Time Polymerase Chain Reaction ; Signal Transduction

The Wnt/β-catenin and bone morphogenetic proteins (BMPs) pathways play important roles in controlling osteogenesis. Using a cell-based kinase inhibitor screening assay, we identified the compound bisindoylmaleimide I (BIM) as a potent agonist of the cytosolic β-catenin accumulation in preosteoblast cells. Through suppressing glycogen synthase kinase 3β enzyme activities, BIM upregulated β-catenin responsive transcription and extended duration of BMP initiated signal. Functional analysis revealed that BIM promoted osteoblast differentiation and bone formation. The treatment of human mesenchymal stem cells with BIM promoted osteoblastogenesis. Our findings provide a new strategy to regulate mesenchymal stem cell differentiation by integration of the cellular signaling pathways.
Animals ; Bone Morphogenetic Proteins ; metabolism ; Cell Differentiation ; drug effects ; Cell Line, Tumor ; Glycogen Synthase Kinase 3 ; metabolism ; Glycogen Synthase Kinase 3 beta ; Indoles ; chemistry ; pharmacology ; Maleimides ; chemistry ; pharmacology ; Mesenchymal Stem Cells ; cytology ; metabolism ; Mice ; Osteoblasts ; cytology ; drug effects ; metabolism ; RNA Interference ; RNA, Small Interfering ; metabolism ; Signal Transduction ; drug effects ; Wnt Proteins ; metabolism ; beta Catenin ; antagonists & inhibitors ; genetics ; metabolism

AIMTo explore the effect and the possible mechanism of ginsenoside Rb1 on beta-amyloid peptide (beta-AP)(25-35) -induced tau protein hyperphosphorylation in cortical neurons.

METHODSWestern blotting and immunocytochemical staining were used to detect tau phosphorylation level, total tau and glycogen synthase kinase-3beta (GSK-3beta) in cortical neurons.

RESULTSAfter exposure to beta-AP(25-35) (20 micromol x L(-1)) for 12 h, the levels of tau protein phosphorylation in the sites of Ser 396, Ser 199/202, Thr 231 and total tau were raised. Meanwhile, the expression of GSK-3beta also increased. Pretreatment with ginsenoside Rbl or lithium chloride, a specific inhibitor of GSK-3beta, markedly reduced beta-AP(25-35)-induced tau hyperphosphorylation and the expression of GSK-3beta.

CONCLUSIONGinsenoside Rb1 can attenuate beta AP(25-35)-induced tau protein hyperphosphorylation in cortical neurons by inhibiting the expression of GSK-3beta.

Amyloid beta-Peptides ; antagonists & inhibitors ; Animals ; Cerebral Cortex ; cytology ; metabolism ; Female ; Fetus ; Ginsenosides ; isolation & purification ; pharmacology ; Glycogen Synthase Kinase 3 ; metabolism ; Glycogen Synthase Kinase 3 beta ; Neurons ; metabolism ; Panax ; chemistry ; Peptide Fragments ; antagonists & inhibitors ; Phosphorylation ; Plants, Medicinal ; chemistry ; Rats ; Rats, Sprague-Dawley ; tau Proteins ; metabolism

Phospholipase Cgamma1 (PLCgamma1) plays an important role in controlling cellular proliferation and differentiation. PLCgamma1 is overexpressed in some tumors, and its overexpression induces solid tumors in nude mice. However, the regulatory mechanisms underlying PLCgamma1-induced cell proliferation are not fully understood. Here we show that overexpression of PLCgamma1 highly phosphorylated glycogen synthase kinase-3beta (GSK-3beta) at serine-9 in 3Y1 fibroblasts. Inhibition of protein kinase C (PKC)s with GF109203X abrogated GSK-3beta phosphorylation by PLCgamma1. We also found that steady-state level of cyclin D1 protein, but not cyclin D1 mRNA, was highly elevated in response to serum stimulation in PLCgamma1-transfected cells as compared with vector-transfected cells. Since GSK-3beta is involved in cyclin D1 proteolysis in response to mitogenic stimulation, PLCgamma1-mediated GSK-3beta phosphorylation may function as a regulation of cyclin D1 accumulation in PLCgamma1-overexpressing cells.
Animals ; Cyclin D1/metabolism ; Epidermal Growth Factor/pharmacology ; Fibroblasts ; Gene Expression ; Glycogen Synthase Kinase 3/chemistry/*metabolism ; Mitogens/pharmacology ; Phospholipase C/genetics/*metabolism ; Phosphorylation/drug effects ; Phosphoserine/*metabolism ; Protein Kinase C/antagonists & inhibitors/*metabolism ; Rats ; Signal Transduction

Progressive dementia is described as the first and most prominent symptom of Alzheimer's disease (AD), and hyperphosphorylation of microtubule associated Tau protein (MAPT) plays a key role in neurodegeneration and neuronal dysfunction in AD and other neurodegenerative diseases. This paper reviews several protein kinases and phosphatases which can phosphorylate/dephosphorylate Tau protein, and evaluates a therapeutic strategy based on targeted inhibition of Tau kinases and activation of Tau phosphatases.
Alzheimer Disease ; metabolism ; physiopathology ; Glycogen Synthase Kinase 3 ; antagonists & inhibitors ; metabolism ; Humans ; Neurodegenerative Diseases ; metabolism ; physiopathology ; Phosphoric Monoester Hydrolases ; metabolism ; Phosphorylation ; Protein Kinases ; metabolism ; tau Proteins ; chemistry ; metabolism ; physiology

Carthamus tinctorius is proved potent in treating ischemic stroke. Flavonoids, such as safflower yellow, hydroxysafflor yellow A(HSYA), nicotiflorin, safflower yellow B, and kaempferol-3-O-rutinoside, are the main substance basis of C. tinctorius in the treatment of ischemic stroke, and HSYA is the research hotspot. Current studies have shown that C. tinctorius can prevent and treat ischemic stroke by reducing inflammation, oxidative stress, and endoplasmic reticulum stress, inhibiting neuronal apoptosis and platelet aggregation, as well as increasing blood flow. C. tinctorius can regulate the pathways including nuclear factor(NF)-κB, mitogen-activated protein kinase(MAPK), signal transducer and activator of transcription protein 3(STAT3), and NF-κB/NLR family pyrin domain containing 3(NLRP3), and inhibit the activation of cyclooxygenase-2(COX-2)/prostaglandin D2/D prostanoid receptor pathway to alleviate the inflammatory development during ischemic stroke. Additionally, C. tinctorius can relieve oxidative stress injury by inhibiting oxidation and nitrification, regulating free radicals, and mediating nitric oxide(NO)/inducible nitric oxide synthase(iNOS) signals. Furthermore, mediating the activation of Janus kinase 2(JAK2)/STAT3/suppressor of cytokine signaling 3(SOCS3) signaling pathway and phosphoinositide 3-kinase(PI3 K)/protein kinase B(Akt)/glycogen synthase kinase-3β(GSK3β) signaling pathway and regulating the release of matrix metalloproteinase(MMP) inhibitor/MMP are main ways that C. tinctorius inhibits neuronal apoptosis. In addition, C. tinctorius exerts the therapeutic effect on ischemic stroke by regulating autophagy and endoplasmic reticulum stress. The present study reviewed the molecular mechanisms of C. tinctorius in the treatment of ischemic stroke to provide references for the clinical application of C. tinctorius.
Carthamus tinctorius/chemistry* ; Chalcone/therapeutic use* ; Cyclooxygenase 2/metabolism* ; Cytokines/metabolism* ; Flavonoids/therapeutic use* ; Glycogen Synthase Kinase 3 beta/metabolism* ; Humans ; Ischemic Stroke/drug therapy* ; Janus Kinase 2/metabolism* ; Mitogen-Activated Protein Kinases/metabolism* ; NF-kappa B/metabolism* ; NLR Family, Pyrin Domain-Containing 3 Protein/metabolism* ; Nitric Oxide/metabolism* ; Nitric Oxide Synthase Type II/metabolism* ; Phosphatidylinositol 3-Kinase/metabolism* ; Phosphatidylinositol 3-Kinases/metabolism* ; Prostaglandin D2 ; Proto-Oncogene Proteins c-akt/metabolism* ; Quinones/pharmacology*

This study is to explore whether the Wnt/beta-catenin signaling pathway is involved in the process of tripchlorolide (T4) protecting against oligomeric Abeta(1-42)-induced neuronal apoptosis. Primary cultured cortical neurons were used for the experiments on day 6 or 7. The oligomeric Abeta(1-42) (5 micromol x L(-1) for 24 h) was applied to induce neuronal apoptosis. Prior to treatment with Abeta(1-42) for 24 h, the cultured neurons were pre-incubated with T4 (2.5, 10, and 40 nmol x L(-1)), Wnt3a (Wnt signaling agonists) and Dkk1 (inhibitors) for indicated time. Then the cell viability, neuronal apoptosis, and protein levels of Wnt, glycogen synthase kinase 3beta (GSK3beta), beta-catenin and phospho-beta-catenin were measured by MTT assay, TUNEL staining and Western blotting, respectively. The result demonstrated that oligomeric Abeta(1-42) induced apoptotic neuronal cell death in a time- and dose-dependent manner. Pretreatment with T4 significantly increased the neuronal cell survival and attenuated neuronal apoptosis. Moreover, oligomeric Abeta(1-42)-induced phosphorylation of beta-catenin and GSK3beta was markedly inhibited by T4. Additionally, T4 stabilized cytoplasmic beta-catenin. These results indicate that tripchlorolide protects against the neurotoxicity of Abeta by regulating Wnt/beta-catenin signaling pathway. This may provide insight into the clinical application of tripchlorolide to Alzheimer's disease.
Amyloid beta-Peptides ; antagonists & inhibitors ; toxicity ; Animals ; Apoptosis ; drug effects ; Cell Survival ; drug effects ; Cells, Cultured ; Cerebral Cortex ; cytology ; Diterpenes ; isolation & purification ; pharmacology ; Female ; Fetus ; Glycogen Synthase Kinase 3 ; metabolism ; Glycogen Synthase Kinase 3 beta ; Neurons ; cytology ; drug effects ; Neuroprotective Agents ; isolation & purification ; pharmacology ; Peptide Fragments ; antagonists & inhibitors ; toxicity ; Phenanthrenes ; isolation & purification ; pharmacology ; Phosphorylation ; Plants, Medicinal ; chemistry ; Pregnancy ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Tripterygium ; chemistry ; Wnt Proteins ; metabolism ; beta Catenin ; metabolism

Alzheimer's disease (AD) is the most common cause of age-related dementia. The neuropathological hallmarks of AD include extracellular deposition of amyloid-beta peptides and neurofibrillary tangles that lead to intracellular hyperphosphorylated tau in the brain. Soluble amyloid-beta oligomers are the primary pathogenic factor leading to cognitive impairment in AD. Neural stem cells (NSCs) are able to self-renew and give rise to multiple neural cell lineages in both developing and adult central nervous systems. To explore the relationship between AD-related pathology and the behaviors of NSCs that enable neuroregeneration, a number of studies have used animal and in vitro models to investigate the role of amyloid-beta on NSCs derived from various brain regions at different developmental stages. However, the Abeta effects on NSCs remain poorly understood because of conflicting results. To investigate the effects of amyloid-beta oligomers on human NSCs, we established amyloid precursor protein Swedish mutant-expressing cells and identified cell-derived amyloid-beta oligomers in the culture media. Human NSCs were isolated from an aborted fetal telencephalon at 13 weeks of gestation and expanded in culture as neurospheres. Human NSCs exposure to cell-derived amyloid-beta oligomers decreased dividing potential resulting from senescence through telomere attrition, impaired neurogenesis and promoted gliogenesis, and attenuated mobility. These amyloid-beta oligomers modulated the proliferation, differentiation and migration patterns of human NSCs via a glycogen synthase kinase-3beta-mediated signaling pathway. These findings contribute to the development of human NSC-based therapy for AD by elucidating the effects of Abeta oligomers on human NSCs.
Amyloid beta-Peptides/*pharmacology ; Animals ; Apoptosis ; Cell Aging ; Cell Movement ; Cell Proliferation ; Culture Media, Conditioned/chemistry/pharmacology ; Fetus/cytology ; Glycogen Synthase Kinase 3/*metabolism ; HEK293 Cells ; Humans ; Mice ; Mice, Inbred C57BL ; Neural Stem Cells/*drug effects/metabolism/physiology ; Signal Transduction ; Telomere Shortening