WSKY, a traditional Chinese decoction, rescues cognitive impairment associated with NMDA receptor antagonism by enhancing BDNF/ERK/CREB signaling

Function and mechanism exploring of icariin in schizophrenia through network pharmacology

This study aims to explore the therapeutic effect and possible mechanisms of icariin in schizophrenia. SD rats were divided into five groups, a control group, a MK801-induced schizophrenia model group, and three icariin treatment groups, with twelve rats in each group. Morris water maze and open field were used to observe the spatial learning and memory ability of rats. Compared with the control group, rats in the MK801-induced model group showed an increase in stereotypic behavior score, distance of spontaneous activities, escape latency, malondialdehyde (MDA) content, and IL-6, IL-1β, TNF-α expression, but a decrease in platform crossing times and superoxide dismutase (SOD) activity (P < 0.05). Furthermore, all the above changes of the model group were reversed after icariin treatment in a dose-dependent manner (P < 0.05). Network pharmacology found that icariin can exert anti-schizophrenic effects through some signaling pathways, such as relaxin, estrogen, and TNF signaling pathways. MAPK1, MAPK3, FOS, RELA, TNF, and JUN were the key targets of icariin on schizophrenia, and their expression was detected in animal models, which was consistent with the predicted results of network pharmacology. Icariin treatment may improve the spatial learning and memory ability of schizophrenic rats through TNF signaling pathway.

The Effects and Mechanism of Scutellaria baicalensis Georgi Stems and Leaves Flavonoids on Myelin Sheath Degeneration Induced by Composite Aβ in Rats

BACKGROUND

Alzheimer's disease is a degenerative disease of the central nervous system, and its characteristic pathological changes are closely associated with Aβ deposition and neurofibrillary tangles. Many studies have found that malignant changes in the myelin sheath and oligodendrocyte (OL) are accompanied by the occurrence and development of AD. Therefore, any method that can resist myelin sheath and OL disorders may be a potential strategy for AD.

OBJECTIVE

To investigate the effects and mechanism of Scutellaria baicalensis Georgi stem and leaf flavonoids (SSFs) on the myelin sheath degeneration induced by Aβ25-35 combined with AlC13 and RHTGF-β1 (composite Aβ) in rats.

METHODS

A rat AD model was established by intracerebroventricular injection of composite Aβ. The Morris water maze was used to screen the memory impairment rat model. The successful model rats were divided into the model group and the 35, 70, and 140 mg/kg SSFS groups. The myelin sheath changes in the cerebral cortex were observed with an electron microscope. The expression of the oligodendrocyte- specific protein claudin 11 was detected with immunohistochemistry. The protein expression levels of myelin oligodendrocyte glycoprotein (MOG), myelin-associated glycoprotein (MAG) and myelin basic protein (MBP), sphingomyelin synthase-1 (SMS1), and sphingomyelinase-2 (SMPD2) were assayed by Western blotting.

RESULTS

The intracerebroventricular injection of composite Aβ caused degeneration of the myelin sheath structure and was accompanied by the decreased claudin 11, MOG, MAG, MBP, and SMS1, and increased SMPD2 protein expression in the cerebral cortex. However, 35, 70, and 140 mg/kg SSFs can differentially ameliorate the above abnormal changes induced by composite Aβ.

CONCLUSION

SSFs can alleviate myelin sheath degeneration and increase the protein expression of claudin 11, MOG, MAG, and MBP, and the effective mechanism may be related to the positive regulation of SMS1 and SMPD2 activities.

Humulus lupulus L. extract and its active constituent xanthohumol attenuate oxidative stress and nerve injury induced by iron overload via activating AKT/GSK3β and Nrf2/NQO1 pathways

Hops, the dried female clusters from Humulus lupulus L., have traditionally been used as folk medicines for treating insomnia, neuralgia, and menopausal disorders. However, its pharmacological action on iron overload induced nerve damage has not been investigated. This study aims to evaluate the protective effects of hops extract (HLE) and its active constituent xanthohumol (XAN) on nerve injury induced by iron overload in vivo and in vitro, and to explore its underlying mechanism. The results showed that HLE and XAN significantly improved the memory impairment of iron overload mice, mainly manifested as shortened latency time, increased crossing platform times and spontaneous alternation ratio, and increased the expression of related proteins. Additionally, HLE and XAN significantly increased superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) activities, and remarkably decreased malondialdehyde (MDA) level in hippocampus. Also, HLE and XAN apparently reduced reactive oxygen species (ROS) content of PC12 cells induced by iron dextran (ID), and improved the oxidative stress level. Moreover, HLE and XAN significantly upregulated the expression of nuclear factor E2-related factor (Nrf2), NAD(P)H quinone oxidoreductase (NQO1), heme oxygenase-1 (HO-1), SOD, phosphorylated AKT (p-AKT), and phosphorylated GSK3β (p-GSK3β) both in hippocampus and PC12 cells. These findings demonstrated the protective effect of HLE and XAN against iron-induced memory impairment, which is attributed to its antioxidant profile by activation of AKT/GSK3β and Nrf2/NQO1 pathways. Also, it was suggested that hops could be a potential candidate for iron overload-related neurological diseases treatment.

ERK/MAPK signalling in the developing brain: Perturbations and consequences

The extracellular regulated kinase/microtubule-associated protein kinase (ERK/MAPK) signalling pathway transduces signals that cause an alteration in the ongoing metabolic pathways and modifies gene expression patterns; thus, influencing cellular behaviour. ERK/MAPK signalling is essential for the proper development of the nervous system from neural progenitor cells derived from the embryonic mesoderm. Several signalling molecules that regulate the well-coordinated process of neurodevelopment transduce developmental information through the ERK/MAPK signalling pathway. The ERK/MAPK is a potential novel therapeutic target in several neurodevelopmental disorders, however, despite years of study, there is still significant uncertainty about the exact mechanism by which the ERK/MAPK signalling pathway elicits specific responses in neurodevelopment. Here, we will review the evidence highlighting the role of ERK/MAPK signalling in neurodevelopment. We will also discuss the structural implication and behavioural deficits associated with perturbed ERK/MAPK signalling pathway in cortical development, whilst examining its contribution to the neuropathology of several neurodevelopmental disorders, such as Autism Spectrum Disorder, Schizophrenia, Fragile X, and Attention Deficit Hyperactive Disorder.

Prenatal Deltamethrin Exposure-Induced Cognitive Impairment in Offspring Is Ameliorated by Memantine Through NMDAR/BDNF Signaling in Hippocampus

Background: Pyrethroids have been widely used in residential and agricultural areas. However, little is known about the effects of prenatal exposure to deltamethrin on cognition in early development of offspring. In this study, the effects of prenatal exposure to deltamethrin on learning and memory abilities, N-methyl-D-aspartate receptor (NMDAR) subunits, brain derived neurotrophic factor (BDNF), Tyrosine kinase B (TrkB) receptor, and phosphorylated cAMP response element binding protein (pCREB) in the hippocampus of offspring rats were investigated.

Experimental Approaches: Groups each of six female SD rats, as F0-generation, were administered with deltamethrin (0, 0.54, 1.35, and 2.7, 9 mg/kg), or memantine (10 mg/kg), or co-administered with deltamethrin (9 mg/kg) and memantine (10 mg/kg) daily by gavage during pregnancy. The learning and memory ability was evaluated using Morris water maze (MWM) task on postnatal day 21. The expression of NMDAR (GluN1, GluN2A, and GluN2B), BDNF, pTrkB/TrkB, and pCREB/CREB in hippocampus were assessed with western blotting.

Results: Prenatal exposure to a relatively low dose of deltamethrin (2.7, 1.35, and 0.54 mg/kg) had no impact on learning and memory abilities or the expression of NMDAR, BDNF, pTrkB, and pCREB in the hippocampus of the exposed offspring. The group treated with 9 mg/kg deltamethrin showed impaired cognitive abilities and decreased expression levels of GluN1, GluN2A, GluN2B, BDNF, pCREB/CREB, and pTrkB/TrkB in the hippocampus. However, the declined cognitive ability were ameliorated by memantine treatment with increased GluN1, GluN2A, GluN2B, BDNF, pCREB/CREB, and pTrkB/TrkB expression in the hippocampus.

Conclusion and Implications: Prenatal exposure to a relatively high does of deltamethrin (9 mg/kg) alters cognition in offsprings and that this cognitive dysfunction can be ameliorated by memantine treatment. Moreover, NMDAR/BDNF signaling may be associated with the effects of prenatal exposure to deltamethrin on cognitive ability in offspring.

Cognitive impairments and low BDNF serum levels in first-episode drug-naive patients with schizophrenia

Evidence shows that BDNF may regulate activity-dependent forms of synaptic plasticity underlying learning and memory. Previous studies reported low BDNF levels and cognitive impairment in the early stage of schizophrenia. Our current study aimed to explore the association between serum BDNF and cognitive functions in first-episode drug-naïve (FEDN) patients with schizophrenia, which has been under-investigated. We recruited 80 FEDN patients and 80 healthy controls and examined the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and serum BDNF in both groups. Patient psychopathology was assessed using the Positive and Negative Syndrome Scale (PANSS). BDNF levels were significantly lower in patients compared to controls (p < 0.001). The RBANS total score and nearly all indexes (all p < 0.001) except for visuospatial/constructional index (p > 0.05) were significantly lower in patients than controls. No significant correlation was found between BDNF and any index or total scores of RBANS in either patients or healthy controls (all p > 0.05). However, the PANSS negative subscale score were negatively associated with both the immediate memory and language indexes (both p < 0.005). Our findings suggest that excessive cognitive impairments are present in the early stage of schizophrenia. Low BDNF may contribute to the pathogenesis of schizophrenia, but maybe not to its cognitive impairments.

Danggui Buxue Tang, a simple Chinese formula containing Astragali Radix and Angelicae Sinensis Radix, stimulates the expressions of neurotrophic factors in cultured SH-SY5Y cells

Background

Danggui Buxue Tang (DBT), a phytoestrogen-enriched Chinese herbal formula, serves as dietary supplement in stimulating the “Blood” functions of menopausal women. In traditional Chinese medicine (TCM) theory, “Blood” has a strong relationship with brain activities. Previous studies supported that some ingredients of DBT possessed neuronal beneficial functions. Therefore, the neurotrophic function and the mechanistic action of DBT were systematically evaluated in cultured human neuroblastoma SH-SY5Y cells.

Methods

The DBT-triggered protein expressions were analyzed by western blotting, while the transcriptional activities of promoters coding for related genes were revealed by luciferase assays. For mechanistic analysis of DBT, Erk1/2 and its inhibitor U0126 were analyzed.

Results

The application of DBT in cultured neuroblastoma cells showed the efficacies in: (1) up-regulation of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF); (2) activation of transcriptional activities of promoters coding for NGF, BDNF, GDNF; (3) activation of Erk1/2 and CREB; and (4) attenuation of the neurotrophic factor expression by the treatment of an Erk1/2 inhibitor.

Conclusions

Our study supports that MAPK/Erk pathway acts as fundamental role in monitoring DBT-induced expression of neurotrophic factors in cultured human neuroblastoma cell. These results shed light in developing the working mechanism of this ancient herbal decoction for its neuronal function.

Electronic supplementary material

The online version of this article (doi:10.1186/s13020-017-0144-y) contains supplementary material, which is available to authorized users.

Neuroprotective effect of a novel Chinese herbal decoction on cultured neurons and cerebral ischemic rats

Background

Historically, traditional Chinese medicine has been widely used to treat stroke. Based on the theory of Chinese medicine and the modern pharmacological knowledge of herbal medicines, we have designed a neuroprotective formula called Post-Stroke Rehabilitation (PSR), comprising seven herbs – Astragalus membranaceus (Fisch.) Bunge, Salvia miltiorrhiza Bunge, Paeonia lactiflora Pall., Cassia obtusifolia L., Ligusticum chuanxiong Hort., Angelica sinensis (Oliv.) Diels, and Glycyrrhiza uralensis Fisch. We aim to examine the neuroprotective activity of PSR in vitro and in vivo, and to explore the underlying molecular mechanisms, to better understand its therapeutic effect and to further optimize its efficacy.

Methods

PSR extract or vehicle was applied to primary rat neurons to examine their survival effects against N-methyl-d-aspartate (NMDA)-elicited excitotoxicity. Whole-cell patch-clamp recording was conducted to examine the NMDA-induced current in the presence of PSR. ERK- and CREB-activation were revealed by western blot analysis. Furthermore, PSR was tested for CRE promoter activation in neurons transfected with a luciferase reporter. The protective effect of PSR was then studied in the rat middle cerebral artery occlusion (MCAO) model. MCAO rats were either treated with PSR extract or vehicle, and their neurobehavioral deficit and cerebral infarct were evaluated. Statistical differences were analyzed by ANOVA or t-test.

Results

PSR prominently reduced the death of cultured neurons caused by NMDA excitotoxicity in a dose-dependent manner, indicating its neuroprotective property. Furthermore, PSR significantly reduced NMDA-evoked current reversibly and activated phosphorylation of ERK and CREB with distinct time courses, with the latter’s kinetics slower. PSR also triggered CRE-promoter activity as revealed by the increased expression of luciferase reporter in transfected neurons. PSR effectively reduced cerebral infarct and deficit in neurological behavior in MCAO rats when PSR decoction was administered starting either 6 days before or 6 h after onset of ischemia.

Conclusions

PSR is neuroprotective both in vitro and in vivo – it protects cultured neurons against NMDA excitotoxicity, and effectively reduces ischemic injury and neurobehavioral deficit in MCAO rats in both the pre- and post-treatment regimens. The underlying neuroprotective mechanisms may involve inhibition of NMDA receptor current and activation of ERK and CREB. This study provides important preclinical data necessary for the further development of PSR for stroke treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1417-1) contains supplementary material, which is available to authorized users.

Z-Guggulsterone Improves the Scopolamine-Induced Memory Impairments Through Enhancement of the BDNF Signal in C57BL/6J Mice

Memory impairment is a common symptom in patients with neurodegenerative disorders, and its suppression could be beneficial to improve the quality of life of those patients. Z-guggulsterone, a compound extracted from the resin of plant Commiphora whighitii, exhibits numerous pharmacological effects in clinical practice, such as treatment of inflammation, arthritis, obesity and lipid metabolism disorders. However, the role and possible mechanism of Z-guggulsterone on brain-associated memory impairments are largely unknown. This issue was addressed in the present study in a memory impairment model induced by scopolamine, a muscarinic acetylcholine receptor antagonist, using the passive avoidance, Y-maze and Morris water maze tests. Results showed that scopolamine significantly decreased the step-through latency and spontaneous alternation of C57BL/6J mice in passive avoidance and Y-maze test, whereas increased the mean escape latency and decreased the swimming time in target quadrant in Morris water maze test. Pretreatment of mice with Z-guggulsterone at doses of 30 and 60 mg/kg effectively reversed the scopolamine-induced memory impairments. Mechanistic studies revealed that Z-guggulsterone pretreatment reversed the scopolamine-induced increase in acetylcholinesterase (AchE) activity, as well as decreases in brain-derived neurotrophic factor (BDNF) protein expression and cAMP response element-binding protein (CREB), extracellular regulated kinase 1/2 (ERK1/2) and protein kinase B (Akt) phosphorylation levels in the hippocampus and cortex. Inhibition of the BDNF signal, however, blocked the memory-enhancing effect of Z-guggulsterone. Therefore, these findings demonstrate that Z-guggulsterone attenuates the scopolamine-induced memory impairments mainly through activation of the CREB-BDNF signaling pathway, thereby exhibiting memory-improving effects.

Impairments of spatial learning and memory following intrahippocampal injection in rats of 3-mercaptopropionic acid-modified CdTe quantum dots and molecular mechanisms

With the rapid development of nanotechnology, quantum dots (QDs) as advanced nanotechnology products have been widely used in neuroscience, including basic neurological studies and diagnosis or therapy for neurological disorders, due to their superior optical properties. In recent years, there has been intense concern regarding the toxicity of QDs, with a growing number of studies. However, knowledge of neurotoxic consequences of QDs applied in living organisms is lagging behind their development, even if several studies have attempted to evaluate the toxicity of QDs on neural cells. The aim of this study was to evaluate the adverse effects of intrahippocampal injection in rats of 3-mercaptopropionic acid (MPA)-modified CdTe QDs and underlying mechanisms. First of all, we observed impairments in learning efficiency and spatial memory in the MPA-modified CdTe QD-treated rats by using open-field and Y-maze tests, which could be attributed to pathological changes and disruption of ultrastructure of neurons and synapses in the hippocampus. In order to find the mechanisms causing these effects, transcriptome sequencing (RNA-seq), an advanced technology, was used to gain the potentially molecular targets of MPA-modified CdTe QDs. According to ample data from RNA-seq, we chose the signaling pathways of PI3K–Akt and MPAK–ERK to do a thorough investigation, because they play important roles in synaptic plasticity, long-term potentiation, and spatial memory. The data demonstrated that phosphorylated Akt (p-Akt), p-ERK1/2, and c-FOS signal transductions in the hippocampus of rats were involved in the mechanism underlying spatial learning and memory impairments caused by 3.5 nm MPA-modified CdTe QDs.