Pingping Zuo

Melatonin Regulates the Viability and Differentiation of Rat Midbrain Neural Stem Cells

Abstract(1) Neurogenesis driven by neural stem cells (NSCs) is regulated by physiological and pathological factors. Melatonin (MT) has profound neurotrophic and neuroprotective effects. Hence, we studied the role of MT in regulating the viability and differentiation of NSCs derived from rat ventral midbrain. (2) NSCs were isolated from the rat ventral midbrain. The viability of NSCs was determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-ulfophenyl)-2H-tetrazolium assay. The differentiation of NSCs was examined by analyzing the expression of the neural markers, MT receptors, brain derived neurotropic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) with semi-quantitative RT-PCR, immunofluorescence cytochemistry, and Western blot. (3) Our results showed that MT could promote the viability of NSCs. In addition, MT could significantly elevate the mRNA and protein levels of tyroxine hydroxylase (TH), a marker of dopaminergic neurons, and decrease the expression of the astrocytes maker glial fibrillary acidic protein (GFAP). MT also increased the production of BDNF and GDNF in the cultured NSCs. Meanwhile, we first found that two subtypes of MT receptors, MT1 and MT2, were expressed in the ventral midbrain NSCs. (4) These results demonstrated that MT could induce NSCs to differentiate into dopaminergic neurons and decrease astrocyte production. These findings also suggest that MT could offer a beneficial tool in guiding directional differentiation of NSCs.

Effects of D-galactose on the expression of hippocampal peripheral-type benzodiazepine receptor and spatial memory performances in rats.

The changes in spatial memory performances and the binding of hippocampal peripheral-type benzodiazepine receptor (PBR) induced by D-galactose (D-gal) were investigated in rats. The animals were randomly divided into two groups: saline-treated group and D-gal-induced aging group. All rats received 56 days of injection followed by 5 days of behavioral tests. The D-gal-induced aging rats presented significant impairment in water maze performance, compared with that in the saline-treated rats. A significant decrease in [3H]PK11195 binding in the synaptosomes from hippocampus in the D-gal-induced aging rats was observed, compared to that in the saline-treated rats. Meanwhile, the Scatchard analysis revealed that there was a decrease in Bmax, with no significant change in KD. Further analysis demonstrated that water maze performance was closely related to the PK11195 binding in all rats. These results suggest that D-gal decreased the density of PBR in hippocampal synaptosomes, which may be attributable to the progressive pathogenesis of aging in rats.

Transplantation of human amniotic cells exerts neuroprotection in MPTP-induced Parkinson disease mice.

To determine the survival and differentiation of cultured Human amniotic cells (HACs) upon transplantation into the brain of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced Parkinson disease (PD) mice. Mouse model of PD was established with injections of MPTP (15 mg/kg, fourth, 2 h interval). After being labeled with PKH26, HACs isolated from human were transplanted into the striatum of PD mice. Immunohistochemistry was performed to evaluate the toxicity of MPTP in the substantia nigra, graft survival and endogenous neurogenesis. Brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) level in the striatum were tested by ELISA. Our results showed that cultured HACs can express the marker of neural progenitor cells and differentiate into neuron, dopaminergic neuron, astrocyte and oligodendrocyte. TH-positive neural cells were significantly reduced in the substantia nigra in the model mice, whereas which increased in transplantation mice. Immunohistology results showed that transplanted HACs survived and migrated in the brain of PD model mouse, though no morphological integration was observed. BrdU-positive cells in the Subventricular zone (SVZ) and neurotrophins of the striatum increased in the transplantation mice. The results suggested that transplanted HACs could survive and promote the endogenous neurogenesis of mice, which maybe related to the increased level of neurotrophins of the striatum.

Dynamic proteomic analysis of protein expression profiles in whole brain of Balb/C mice subjected to unpredictable chronic mild stress: implications for depressive disorders and future therapies.

The etiology and pathophysiology of depression remain unknown. Previous works were mostly performed on single observation time-point which might be insufficiently to reveal the molecular events changed during the disease development. Adult BALB/c mice were exposed to unpredictable chronic mild stress (UCMS) for different periods and differential 2D gel electrophoresis (DIGE) approach was employed to the brain tissue to explore the molecular disease signatures. Sustained elevation of corticosterone level was observed, suggesting the hyperactivity of hypothalamic-pituitary-adrenal (HPA) axis when the mice were subjected to the stressful situation. The behavioral results indicated the depressive alterations of the mice exposing to UCMS. The altered proteins identified by proteomics showed that abnormal energy mobilization under stress condition was accompanied by overproduction of reactive oxygen species (ROS) and endoplasmic reticulum (ER) stress. Cytoskeleton protein and anti-oxidant enzymes were also changed by UCMS treatment. The results of biochemical and immunohistochemical assay confirmed the changes identified by DIGE analysis. These results indicated that the insufficiency of ATP synthesis, overwhelming ROS production and ER stress subsequently contributed to the cytoskeletal damage and inhibition to expression of some anti-oxidant proteins, which might ultimately bring functional neuron to apoptosis or death. Proteins whose expression is affected may provide tools for potential treatment strategies.

Effects of long-term, low-dose sex hormone replacement therapy on hippocampus and cognition of postmenopausal women of different apoE genotypes

AbstractAim:To study the effects of long-term, low-dose sex hormone replacement therapy (HRT) on the volume and biochemical changes of the hippocampus in postmenopausal women carrying apolipoprotein E (apoE) gene ɛ3 or ɛ4.Methods:Eightythree postmenopausal women who had used a low dose of HRT for over 4 years were selected as the HRT group, and 99 postmenopausal women with matched age and education were enrolled as the control group. ApoE alleles were analyzed by PCR. Magnetic resonance imaging was performed to determine the volume of the brain hippocampus. Proton magnetic resonance spectroscopy was used to detect the biochemical changes in the anterior cingulate cortex and hippocampus in apoE ɛ4 and ɛ3 carriers. Six common cognitive tests were used to make an overall evaluation of cognitive function.Results:Analysis with the apoE ɛ4 carriers showed that the volume of the hippocampus of the control group were significantly lower than those of the HRT group. The biochemical analysis showed that there was an increase of N-acetylaspartate (NAA)/total creatine (tCr) and a decrease of myoinositol (mI)/tCr in the hippocampus of apoE ɛ4 carriers in the HRT group, compared with the control group. For the apoE ɛ3 carriers, the least squares means (LSMEAN) of the HRT group was higher than that of the control group.Conclusion:This study showed that long-term, low dose HRT might be beneficial for reducing the risk of AD development invulnerable postmenopausal women. Meanwhile, HRT could increase the LSMEAN of apoE ɛ3 carriers.

Protective effects of octacosanol on 6-hydroxydopamine-induced Parkinsonism in rats via regulation of ProNGF and NGF signaling.

AbstractAim:To investigate the protective effects of octacosanol in 6-hydroxydopamine-induced Parkinsonian rats and find whether octacosanol has effects on pro nerve growth factor (pro-NGF), NGF and the downstream effector proteins.Methods:Behavioral tests, enzymatic assay, tyrosine hydroxylase immunohistochemistry, TUNEL and Western blot were used to investigate the effects of octacosanol in this rat model of PD.Results:Oral administration of octacosanol (35–70 mg/kg, po for 14 d) significantly improved the behavioral impairments in rats induced by 6-OHDA and dose-dependently preserved the free radical scavenging capability of the striatum. Octacosanol treatment also effectively ameliorated morphological appearances of TH-positive neuronal cells in nigrostriatal systems and decreased the apoptotic cells induced by 6-OHDA in striatum. In addition, octacosanol strikingly blocked the 6-OHDA-induced increased expression of proNGF-p75NTR-sortilin death signaling complex and its downstream effector proteins. Meantime, octacosanol prevented the decreased levels of NGF, its receptors TrkA and p-Akt which together mediated the cell survival pathway.Conclusion:The findings implicated that the anti-parkinsonism effects afforded by octacosanol might be mediated by its neuro-microenvironment improving potency through retrieving the ratios of proNGF:NGF and the respective receptors p75NTR:TrkA in vivo. Due to its excellent tolerability and non-toxicity, octacosanol may be a promising agent for PD treatment.

Gene expression profile of amyloid beta protein-injected mouse model for Alzheimer disease

AbstractAim:To investigate the gene expression profile changes in the cerebral cortex of mice injected icv with amyloid beta-protein (Aβ) fragment 25-35 using cDNA microarray.Methods:Balb/c mice were randomly divided into a control group and Aβ-treated group. The Morris water maze test was performed to detect the peffect of Aβ-injection on the learning and memory of mice. Atlas Mouse 1.2 Expression Arrays containing 1176 genes were used to investigate the gene expression pattern of each group.Results:The gene expression profiles showed that 19 genes including TBX1, NF-κB, AP-1/c-Jun, cadherin, integrin, erb-B2, and FGFR1 were up-regulated after 2 weeks of icv administration of Aβ; while 12 genes were down-regulated, including NGF, glucose phosphate isomerase 1, AT motif binding factor 1, Na+/K+-ATPase, and Akt.Conclusion:The results provide important leads for pursuing a more complete understanding of the molecular events of Aβ-injection into mice with Alzheimer disease.

The Mechanism of Memory Impairment Induced by Aβ Chronic Administration Involves Imbalance between Cytokines and Neurotrophins in the Rat Hippocampus

It has been demonstrated that the onset and progression of Alzheimers disease (AD) are associated with inflammatory disorders in the brain. Although the interactions of inflammatory cytokines with neurotrophins have been reported in vitro, the balance change between inflammatory cytokines and neurotrophic factors (NTFs), such as nerve growth factor (NGF), brain derived neurotrophic factor (BDNF), and glial cell line-derived neurotrophic factor (GDNF), due to amyloid β (Aβ) chronic administration in vivo is still unclear. The hypothesis of the present study was that the accumulation of Aβ activated glial cells to produce inflammatory mediators and NTFs to maintain the neurons survival, however the failure of crosstalk between NTFs and inflammatory cytokines might occur in the brain and the NTFs expressions would decrease after Aβ chronic treatment, which, therefore, would contribute to the neuronal death and memory impairments. Thus, the present study measured the learning and memory behavior, glial cells activities, cytokines (IL-1α, IL-1β and TNF-α) concentrations and NTFs (NGF, BDNF and GDNF) gene and protein levels in rats after i.c.v injection of Aβ(25-35) for 14 days. The results showed that Aβ (25-35)-treated animals exhibited failure of balance between inflammatory cytokines and NTFs system (increased cytokines levels, decreased NGF protein expression and reduced NTFs gene transcriptions), which might contribute to the cognitive impairments. The findings from this study provide valuable evidence that correct regulation of the crosstalk between inflammatory cytokines and NTFs could be a direction for AD therapy in the future.

Gossypium herbaceam Extracts Inhibited NF-κB Activation to Attenuate Spatial Memory Impairment and Hippocampal Neurodegeneration Induced by Amyloid-β in Rats

Amyloid-beta (Abeta) is considered to be responsible for the pathogenesis of Alzheimers disease. In the present study, the protective effect of Gossypium herbaceam extracts (GHE) on learning and memory impairment induced by Abeta were examined in vivo using Morris water maze and step through task. Furthermore, the antioxidant activity and neuroprotective effect of GHE was investigated with methods of histochemistry and biochemistry. These data showed that oral administration with GHE at the doses of 35, 70 and 140 mg/kg exerted an improved effect on the learning and memory impairment in rats induced by intracerebroventricular (i.c.v.) injection of 10 microg of Abeta(25-35). Subsequently, the GHE afforded a beneficial action on promotion on the activity of glutathione peroxidase and catalase, as well as inhibition on the NF-kappaB activation in the hippocampus followed by the presence of Abeta(25-35). Meanwhile, the number of degenerating neurons with an apoptotic feature was dramatically decreased in hippocampus after treatment with GHE, implicating that its antioxidant stress and inhibition of NF-kappaB activation could be involved in the mechanism underlying neuroprotection of GHE against Abeta-induced cell death. These findings suggested that GHE might be a potential agent for treatment of Alzheimers disease.

Enhanced in vivo antitumor efficacy of dual-functional peptide-modified docetaxel nanoparticles through tumor targeting and Hsp90 inhibition

Although conventional anticancer drugs exhibit excellent efficacy, serious adverse effects and/or even toxicity have occurred due to their nonselectivity. Moreover, active targeting approaches have not consistently led to successful outcomes. Ligands that simultaneously possess targeting capability and exert a strong influence on intracellular signaling cascades may be expected to improve the therapeutic efficacy of active targeting nanoparticulate carriers. In this study, we screened a targeting peptide, LPLTPLP, which specifically bound to non-small cell lung cancer (NSCLC) specimens in vitro. Surprisingly, this peptide inhibited the expression of Hsp90 and induced apoptosis by preventing autophagy in A549 cells treated with docetaxel. The results suggested that this peptide might be used as a promising dual-functional ligand for cancer treatment. Based on these findings, we designed and developed a novel active targeting delivery system by modifying docetaxel nanoparticles (DNP) with the dual-functional ligand LPLTPLP. We consistently demonstrated that the cellular uptake of nanoparticles (NPs) was significantly enhanced in vitro. Furthermore, the targeting NPs exhibited significantly improved antitumor efficacy and biodistribution compared with nontargeting nanodrug and free docetaxel. These findings demonstrate the feasibility of dual-functional NPs for efficient anticancer therapy.