A combined DHA-rich fish oil and cocoa flavanols intervention does not improve cognition or brain structure in older adults with memory complaints: results from the CANN randomized, controlled parallel-design study.

BACKGROUND: There is evidence that both omega-3 long-chain polyunsaturated fatty acids (PUFAs) (eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) and cocoa flavanols can improve cognitive performance in both healthy individuals and in those with memory complaints. However, their combined effect is unknown. OBJECTIVES: To investigate the combined effect of EPA/DHA and cocoa flavanols (OM3FLAV) on cognitive performance and brain structures in older adults with memory complaints. METHODS: A randomized placebo-controlled trial of DHA-rich fish oil (providing 1.1 g/d DHA and 0.4 g/d EPA) and a flavanol-rich dark chocolate (providing 500 mg/d flavan-3-ols) was conducted in 259 older adults with either subjective cognitive impairment or mild cognitive impairment. Participants underwent assessment at baseline, 3 mo, and 12 mo. The primary outcome was the number of false-positives on a picture recognition task from the Cognitive Drug Research computerized assessment battery. Secondary outcomes included other cognition and mood outcomes, plasma lipids, brain-derived neurotrophic factor (BDNF), and glucose levels. A subset of 110 participants underwent structural neuroimaging at baseline and at 12 mo. RESULTS: 197 participants completed the study. The combined intervention had no significant effect on any cognitive outcomes, with the exception of reaction time variability (P = 0.007), alertness (P < 0.001), and executive function (P < 0.001), with a decline in function observed in the OM3FLAV group (118.6 [SD 25.3] at baseline versus 113.3 [SD 25.4] at 12 mo for executive function) relative to the control, and an associated decrease in cortical volume (P = 0.039). Compared with the control group, OM3FLAV increased plasma HDL, total cholesterol ratio (P < 0.001), and glucose (P = 0.008) and reduced TG concentrations (P < 0.001) by 3 mo, which were sustained to 12 mo, with no effect on BDNF. Changes in plasma EPA and DHA and urinary flavonoid metabolite concentrations confirmed compliance to the intervention. CONCLUSIONS: These results suggest that cosupplementation with ω-3 PUFAs and cocoa flavanols for 12 mo does not improve cognitive outcomes in those with cognitive impairment. This trial was registered at clinicaltrials.gov as NCT02525198.

Polygonatum sibiricum ameliorated cognitive impairment of naturally aging rats through BDNF-TrkB signaling pathway.

Cognitive dysfunction is high in the elderly population and seriously affects the quality of life. Brain-derived neurotrophic factor (BDNF) is one of the key neurotrophic proteins, and activation of BDNF-TrkB is considered an effective strategy to improve cognitive dysfunction during aging. In this study, administration of polygonatum sibiricum (PS) for 5 months effectively ameliorates the cognitive function, improving the Nissl body state in cortex and hippocampus in aging rats. In addition, PS can improve the synaptic structure and increase the number of synapses. Furthermore, PS reverses the reduction of synaptic plasticity-related proteins postsynaptic density protein 95 (PSD-95) and synaptophysin during aging and up-regulates the expression of BDNF-TrkB. In conclusion, PS improves cognitive dysfunction and enhances synaptic plasticity in naturally aged rats by regulating the BDNF-TrkB signaling pathway. PS has the potential to be developed as a novel and promising functional health food for the elderly. PRACTICAL APPLICATIONS: Polygonatum sibiricum (PS) is a traditional Chinese medicine, which has been included in the homologous plant of medicine and food. PS has been widely used to treat lung diseases, diabetes and antiaging in clinical. Studies have confirmed that PS can accelerate the repair and regeneration of damaged neurons, reverse the changes in synaptic structure, and improve the ability of learning and memory. Our study confirmed that PS significantly improved the cognitive function in aging rats. PS has great potential to be developed as a functional food for improving neurological function and anti-aging.

Ulexite modulates the neurotoxicological outcomes of acetylferrocene-exposed rainbow trout.

In this study, the neuroprotective action potential by ulexite (UX) (18.75 mg/L) against acetylferrocene (AFC) (3.82 mg/L) induced neurotoxicity was aimed to investigate in brain tissues of Oncorhynchus mykiss. For this purpose, the effects on neurotoxicity markers, proinflammatory cytokines, antioxidant immune system, DNA, and apoptosis mechanisms were assessed on brain tissues in the 48-96  h of the 96- trial period. In this research, it was determined that brain-derived nerve cell growth factor (BDNF) level and acetylcholinesterase (AChE) activity were inhibited in the brain tissue compared to the control group by AFC. In addition, inhibition in glutathione peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH) values (which are antioxidant system biomarkers), and inductions in malondialdehyde (MDA) and myeloperoxidase (MPO) amounts (which are indicators of lipid peroxidation) were determined (p < 0.05) after exposure to AFC. And, while tumor necrosis factor-α (TNF-α) and IL-6 levels were increased in the AFC-exposed group, Nrf-2 levels were found to be remarkably decreased. Upregulation was also detected in 8-hydroxydeoxyguanosine (8-OHdG) and caspase-3 levels, which are related to DNA damage and apoptosis mechanism. On the contrary, UX (single/with AFC) suppressed the AChE and BDNF inhibition by AFC. Moreover, UX mitigated AFC-induced oxidative, inflammatory, and DNA damage and attenuated AFC-mediated neurotoxicity via activating Nrf2 signaling in fish. Collectively, our findings revealed that UX supplementation might exert beneficial effects and may be considered as a natural and promising neuroprotective agent against AFC-induced toxicity.

Clathrin-nanoparticles deliver BDNF to hippocampus and enhance neurogenesis, synaptogenesis and cognition in HIV/neuroAIDS mouse model.

Brain derived neurotrophic factor (BDNF) promotes the growth, differentiation, maintenance and survival of neurons. These attributes make BDNF a potentially powerful therapeutic agent. However, its charge, instability in blood, and poor blood brain barrier (BBB) penetrability have impeded its development. Here, we show that engineered clathrin triskelia (CT) conjugated to BDNF (BDNF-CT) and delivered intranasally increased hippocampal BDNF concentrations 400-fold above that achieved previously with intranasal BDNF alone. We also show that BDNF-CT targeted Tropomyosin receptor kinase B (TrkB) and increased TrkB expression and downstream signaling in iTat mouse brains. Mice were induced to conditionally express neurotoxic HIV Transactivator-of-Transcription (Tat) protein that decreases BDNF. Down-regulation of BDNF is correlated with increased severity of HIV/neuroAIDS. BDNF-CT enhanced neurorestorative effects in the hippocampus including newborn cell proliferation and survival, granule cell neurogenesis, synaptogenesis and increased dendritic integrity. BDNF-CT exerted cognitive-enhancing effects by reducing Tat-induced learning and memory deficits. These results show that CT bionanoparticles efficiently deliver BDNF to the brain, making them potentially powerful tools in regenerative medicine.

Gastrodin promotes the regeneration of peripheral nerves by regulating miR-497/BDNF axis.

BACKGROUND: Gastrodin (GAS), is a kind of phenolic compound extracted from the traditional Chinese herbal medicine Gastrodia elata Blume (GEB). This study was aimed at probing into the protective effect of GAS on peripheral nerve injury (PNI) and the underlying mechanism. METHODS: A rat model with PNI was established, followed by intraperitoneal injection of GAS (20 mg/kg/day). Sciatic nerve function index (SFI) was used to analyze the function of sciatic nerve. The amplitude and latency of compound muscle action potential (CMAP) were examined by electrophysiology. Schwann cells (SCs) were isolated from fetal rats and treated with GAS 200 µg/mL, and H2O2-induced model of oxidative stress injury was established. EdU and Transwell assays were adopted to detect the viability and migration of SCs. Dual-luciferase reporter gene assays were applied to verify the binding site between miR-497 and brain-derived neurotrophic factor (BDNF) 3'UTR. MiR-497 expression was probed by quantitative real-time polymerase chain reaction (qRT-PCR). BDNF, neurofilament-200 (NF-200) and myelin basic protein (MBP) expression levels were detected by Western blotting. Malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, glutathione content (GSH) and catalase (CAT) activity in SCs were also measured. RESULTS: GAS treatment could significantly increase the SFI and amplitude of CMAP, shorten the refractory period, and ameliorate muscle atrophy of the rats with PNI. GAS treatment could markedly restrain miR-497 expression and increase the expression levels of BDNF, NF-200 and MBP in SCs. BDNF was confirmed as the target of miR-497 and BDNF overexpression could reverse the impacts of miR-497 overexpression on the proliferation, migration, and oxidative stress response of SCs. CONCLUSIONS: GAS promotes the recovery of PNI via modulating miR-497 / BDNF axis and inhibiting oxidative stress.

Regulation of Neurogenesis and Neuronal Differentiation by Natural Compounds.

Neuronal damage or degeneration is the main feature of neurological diseases. Regulation of neurogenesis and neuronal differentiation is important in developing therapies to promote neuronal regeneration or synaptic network reconstruction. Neurogenesis is a multistage process in which neurons are generated and integrated into existing neuronal circuits. Neuronal differentiation is extremely complex because it can occur in different cell types and can be caused by a variety of inducers. Recently, natural compounds that induce neurogenesis and neuronal differentiation have attracted extensive attention. In this paper, the potential neural induction effects of medicinal plant-derived natural compounds on neural stem/progenitor cells (NS/PCs), the cultured neuronal cells, and mesenchymal stem cells (MSCs) are reviewed. The natural compounds that are efficacious in inducing neurogenesis and neuronal differentiation include phenolic acids, polyphenols, flavonoids, glucosides, alkaloids, terpenoids, quinones, coumarins, and others. They exert neural induction effects by regulating signal factors and cellspecific genes involved in the process of neurogenesis and neuronal differentiation, including specific proteins (ß-tubulin III, MAP-2, tau, nestin, neurofilaments, GFAP, GAP-43, NSE), related genes and proteins (STAT3, Hes1, Mash1, NeuroD1, notch, cyclin D1, SIRT1, Reggie-1), transcription factors (CREB, Nkx-2.5, Ngn1), neurotrophins (BDNF, NGF, NT-3), and signaling pathways (JAK/STAT, Wnt/ß-catenin, MAPK, PI3K/Akt, GSK-3ß/ß-catenin, Ca2+/CaMKII/ATF1, Nrf2/HO-1, BMP).The natural compounds with neural induction effects are of great value for neuronal regenerative medicine and provide promising prevention and treatment strategies for neurological diseases.

Eucommia Leaf Extract Induces BDNF Production in Rat Hypothalamus and Enhances Lipid Metabolism and Aerobic Glycolysis in Rat Liver.

BACKGROUND: Mutations in the brain-derived neurotrophic factor (BDNF) gene and its receptor, tyrosine receptor kinase B (TrkB), have been reported to cause severe obesity in rodents. Our previous study demonstrated that the oral administration of 5% Eucommia leaf extract (ELE) or ELE aroma treatment (ELE aroma) produced anti-obesity effects. OBJECTIVE: In this study, we investigated the effects of ELE on glycolysis and lipid metabolism in male Sprague-Dawley rats, as well as the effects of ELE on BDNF in rat hypothalamus. METHODS AND RESULTS: A significant reduction and a reduction tendency in the respiratory quotient were observed in association with 5% ELE and ELE aroma treatment, respectively. Furthermore, RT-qPCR results showed significant increases in Cpt2, Acad, Complex II, and Complex V mRNA levels in the liver with both treatments. In addition, in rat hypothalamus, significant elevations in BDNF, Akt, PLCγ proteins and CREB phosphorylation were observed in the 5% ELE group and the ELE aroma group. Furthermore, the Ras protein was significantly increased in the ELE aroma group. On the other hand, significant dephosphorylation of ERK1/2 was observed by the western blotting in the 5% ELE group and the ELE aroma group. CONCLUSION: These findings suggest that the ELE treatment enhances the lipid metabolism and increases the aerobic glycolytic pathway, while ELE-induced BDNF may affect such energy regulation. Therefore, ELE has the possibility to control metabolic syndrome.

n-3 Fatty Acid and Its Metabolite 18-HEPE Ameliorate Retinal Neuronal Cell Dysfunction by Enhancing Müller BDNF in Diabetic Retinopathy.

Diabetic retinopathy (DR) is a widespread vision-threatening disease, and neuroretinal abnormality should be considered as an important problem. Brain-derived neurotrophic factor (BDNF) has recently been considered as a possible treatment to prevent DR-induced neuroretinal damage, but how BDNF is upregulated in DR remains unclear. We found an increase in hydrogen peroxide (H2O2) in the vitreous of patients with DR. We confirmed that human retinal endothelial cells secreted H2O2 by high glucose, and H2O2 reduced cell viability of MIO-M1, Müller glia cell line, PC12D, and the neuronal cell line and lowered BDNF expression in MIO-M1, whereas BDNF administration recovered PC12D cell viability. Streptozocin-induced diabetic rats showed reduced BDNF, which is mainly expressed in the Müller glia cell. Oral intake of eicosapentaenoic acid ethyl ester (EPA-E) ameliorated BDNF reduction and oscillatory potentials (OPs) in electroretinography (ERG) in DR. Mass spectrometry revealed an increase in several EPA metabolites in the eyes of EPA-E-fed rats. In particular, an EPA metabolite, 18-hydroxyeicosapentaenoic acid (18-HEPE), induced BDNF upregulation in Müller glia cells and recovery of OPs in ERG. Our results indicated diabetes-induced oxidative stress attenuates neuroretinal function, but oral EPA-E intake prevents retinal neurodegeneration via BDNF in Müller glia cells by increasing 18-HEPE in the early stages of DR.

In vitro modeling of dendritic atrophy in Rett syndrome: determinants for phenotypic drug screening in neurodevelopmental disorders.

Dendritic atrophy, defined as the reduction in complexity of the neuronal arborization, is a hallmark of several neurodevelopmental disorders, including Rett Syndrome (RTT). RTT, affecting 1:10,000 girls worldwide, is mainly caused by mutations in the MECP2 gene and has no cure. We describe here an in vitro model of dendritic atrophy in Mecp2-/y mouse hippocampal primary cultures, suitable for phenotypic drug-screening. Using High-Content Imaging techniques, we systematically investigated the impact of culturing determinants on several parameters such as neuronal survival, total dendritic length, dendritic endpoints, soma size, cell clusterization, spontaneous activity. Determinants included cell-seeding density, glass or polystyrene substrates, coating with poly-Ornithine with/without Matrigel and miniaturization from 24 to 96-half surface multiwell plates. We show that in all plate-sizes at densities below 320 cells/mm2, morphological parameters remained constant while spontaneous network activity decreased according to the cell-density. Mecp2-/y neurons cultured at 160 cells/mm2 density in 96 multiwell plates, displayed significant dendritic atrophy and showed a marked increase in dendritic length following treatment with Brain-derived neurotrophic factor (BDNF) or Mirtazapine. In conclusion, we have established a phenotypic assay suitable for fast screening of hundreds of compounds, which may be extended to other neurodevelopmental diseases with dendritic atrophy.

Inverted U-shaped response of a standardized extract of Centella asiatica (ECa 233) on memory enhancement.

The herb Centella asiatica has long been considered a memory tonic. A recent review found no strong evidence for improvement of cognitive function, suggesting negative results were due to limitations in dose, standardization and product variation. We used a standardized extract of C. asiatica (ECa 233) to study behavioral, cellular and molecular effects on learning and memory enhancement. ECa 233 (10, 30, and 100 mg/kg) was given orally to normal rats twice a day for 30 days. We used the Morris water maze to test spatial learning and performed acute brain slice recording to measure changes of synaptic plasticity in the hippocampus, a core brain region for memory formation. Plasticity-related protein expressions (NR2A, NR2B, PSD-95, BDNF and TrkB) in hippocampus was also measured. Rats receiving 10 and 30 mg/kg doses showed significantly enhanced memory retention, and hippocampal long-term potentiation; however, only the 30 mg/kg dose showed increased plasticity-related proteins. There was an inverted U-shaped response of ECa 233 on memory enhancement; 30 mg/kg maximally enhanced memory retention with an increase of synaptic plasticity and plasticity-related proteins in hippocampus. Our data clearly support the beneficial effect on memory retention of a standardized extract of Centella asiatica within a specific therapeutic range.

BDNF and NT3 Reprogram Human Ectomesenchymal Dental Pulp Stem Cells to Neurogenic and Gliogenic Neural Crest Progenitors Cultured in Serum-Free Medium.

BACKGROUND/AIMS: Human Dental Pulp Stem Cells (hDPSCs) are one of the most promising types of cells to regenerate nerve tissues. Standard DMEM+10% fetal bovine serum (FBS) culture medium allows a fast expansion of hDPSC as a surface-adherent cell monolayer. However, the use of FBS also compromises the clinical use of these protocols, and its longterm presence favors hDPSCs differentiation toward mesenchymal cell-derived lineages, at the expense of a reduced capability to generate neural cells. The objective of this work was to characterize the role of neurotrophin signaling on hDPSCs using a serum-free culture protocol, and to assess the neurogenic and gliogenic capacity of hDPSCs for future nerve tissue bioengineering and regeneration. METHODS: We compared the different expression of neurotrophin receptors by RT-PCR, Q-PCR, and IF of hDPSCs cultured with different growth media in the presence or absence of serum. Moreover, we assessed the response of hDPSCs to stimulation of neurotransmitter receptors by live cell calcium imaging under these different media. Finally, we compared the osteogenic potential of hDPSCs by Alizarin red staining, and the differentiation to gliogenic/neurogenic fates by immunostaining for Schwann lineage and neuronal lineage markers. We tested a commercial serum-free medium designed for the growth of mesenchymal stem cells: StemPro MSCTM (STP). RESULTS: hDPSCs cultured in STP generated small non-adherent floating dentospheres that showed very low proliferation rates, in contrast to standard FBS-containing medium. We found that hDPSCs grown in STP conditions overexpressed neurotrophin receptor genes NTRK2 (TrkB) and NTRK3 (TrkC). Interestingly, the stimulation of these receptors by adding their respective ligands BDNF and NT-3 to STP medium enhanced the neural crest (NC) progenitor features of cultured hDPSCs. We observed a 10 to 100-fold increase of migratory NC cell markers HNK1 and P75NTR, and a significant overexpression of pluripotency core factors SOX2, OCT4 and NANOG. Moreover, hDPSCs cultured in BDNF/NT-3 supplemented STP showed a largely increased potential to differentiate towards neuronal and Schwann glial lineage cells, assessed by positive immunostaining for DCX, NeuN and S100ß, p75NTR markers, respectively. CONCLUSION: Our results demonstrate that the use of BDNF and NT-3 combined with STP induced the partial reprogramming of ectomesenchymal hDPSCs to generate early NC progenitor cells, which are far more competent for neuronal and glial differentiation than hDPSCs grown in the presence of FBS.

Glutamatergic Innervation onto Striatal Neurons Potentiates GABAergic Synaptic Output.

Striatal output pathways are known to play a crucial role in the control of movement. One possible component for shaping the synaptic output of striatal neuron is the glutamatergic input that originates from cortex and thalamus. Although reports focusing on quantifying glutamatergic-induced morphological changes in striatum exist, the role of glutamatergic input in regulating striatal function remains poorly understood. Using primary neurons from newborn mice of either sex in a reduced two-neuron microcircuit culture system, we examined whether glutamatergic input modulates the output of striatal neurons. We found that glutamatergic input enhanced striatal inhibition in vitro With a glutamatergic partner from either cortex or thalamus, we attributed this potentiation to an increase in the size of quantal IPSC, suggesting a strengthening of the postsynaptic response to GABAergic signaling. Additionally, a differential effect of cortical and thalamic innervation onto striatal GABAergic neurons output was revealed. We observed that cortical, but not thalamic input, enhanced the number of releasable GABAergic synaptic vesicles and morphological synapses. Importantly, these alterations were reverted by blockade of neuronal activity and glutamate receptors, as well as disruption of BDNF-TrkB signaling. Together, our data indicate, for first time, that GABAergic synapse formation in corticostriatal pairs depends on two parallel, but potentially intersecting, signaling pathways that involve glutamate receptor activation in striatal neurons, as well as BDNF signaling. Understanding how cortical and thalamic inputs refine striatal output will pave the way toward dissecting basal ganglia activity in both physiological and pathological conditions.SIGNIFICANCE STATEMENT Striatal GABAergic microcircuits are critical for motor function. However, the mechanisms controlling striatal output, particularly at the level of synaptic strength, are unclear. Using two-neuron culture system, we quantified the synaptic output of individual striatal GABAergic neurons paired with a glutamatergic partner and studied the influence of the excitatory connections that are known to be interregionally formed in vivo We found that glutamatergic input potentiated striatal inhibitory output, potentially involving an increased feedback and/or feedforward inhibition. Moreover, distinct components of glutamatergic innervation, such as firing activity or release of neurotrophic factors were shown to be required for the glutamatergic-induced phenotype. Investigation, therefore, of two-neuron in vitro microcircuits could be a powerful tool to explore synaptic mechanisms or disease pathophysiology.

Brain-Derived Neurotrophic Factor Attenuates Septic Myocardial Dysfunction via eNOS/NO Pathway in Rats.

Sepsis-induced myocardial dysfunction increases mortality in sepsis, yet the underlying mechanism is unclear. Brain-derived neurotrophic factor (BDNF) has been found to enhance cardiomyocyte function, but whether BDNF has a beneficial effect against septic myocardial dysfunction is unknown. Septic shock was induced by cecal ligation and puncture (CLP). BDNF was expressed in primary cardiomyocytes, and its expression was significantly reduced after sepsis. In rats with sepsis, a sharp decline in survival was observed after CLP, with significantly reduced cardiac BDNF expression, enhanced myocardial fibrosis, elevated oxidative stress, increased myocardial apoptosis, and decreased endothelial nitric oxide (NO) synthase (eNOS) and NO. Supplementation with recombined BDNF protein (rhBDNF) enhanced myocardial BDNF and increased survival rate with improved cardiac function, reduced oxidative stress, and myocardial apoptosis, which were associated with increased eNOS expression, NO production, and Trk-B, a BDNF receptor. Pretreatment with NOS inhibitor, N (omega)-nitro-L-arginine methyl ester, abolished the abovementioned BDNF cardioprotective effects without affecting BDNF and Trk-B. It is concluded that BDNF protects the heart against septic cardiac dysfunction by reducing oxidative stress and apoptosis via Trk-B, and it does so through activation of eNOS/NO pathway. These findings provide a new treatment strategy for sepsis-induced myocardial dysfunction.

Role of brain-derived neurotrophic factor and nerve growth factor in the regulation of Neuropeptide W in vitro and in vivo.

Nerve growth factor (NGF) and Brain-derived neurotrophic factor (BDNF) are neurotrophic factors involved in the growth, survival and functioning of neurons. In addition, a possible role of neurotrophins, particularly BDNF, in HPA axis hyperactivation has recently been proposed. Neuropeptide W (NPW) is an endogenous peptide ligand for the GPR7 and GPR8 and a stress mediator in the hypothalamus. It activates the HPA axis by working on hypothalamic corticotrophin-releasing hormone (CRH). No information is available about the interrelationships between neurotrophines like NGF/BDNF and NPW. We studied the effect and underlying mechanisms of NGF/BDNF on the production of NPW in PC12 cells and hypothalamus. NGF time- and concentration-dependently stimulated the expression of NPW in PC12 cells. The effect of NGF was blocked by the inhibition of PI3K/Akt signal pathway with specific inhibitors for PI3K or AktsiRNA for Akt while inhibition of ERK pathway had no effect. Moreover, BDNF concentration-dependently induced the expression of NPW mRNA and decreased the expression of NPY mRNA in primary cultured hypothalamic neurons which was also blocked by a PI3K kinase inhibitor. Finally, in vivo study showed that exogenous BDNF injected icv increased NPW production in the hypothalamus and this effect was reversed by a PI3 kinase inhibitor. These results and the fact that BDNF was able to stimulate the expression of CRH demonstrated that neurotrophines can modulate the expression of NPW in neuronal cells via the PI3K/Akt pathway and suggest that BDNF might be involved in functions of the HPA axis, at least in part by modulating the expression of NPW/NPY and CRH.

Acupuncture Improves Cerebral Microenvironment in Mice with Alzheimer's Disease Treated with Hippocampal Neural Stem Cells.

Transplantation with neural stem cells (NSCs) is a promising clinical therapy for Alzheimer's disease (AD). However, the final fate of grafted NSCs is mainly determined by the host microenvironment. Therefore, this study investigated the role of Sanjiao acupuncture in the NSCs-treated hippocampus of a mouse model, senescence-accelerated mouse prone 8 (SAMP8) using Western blot, real-time fluorescent PCR, and immunofluorescence techniques. Meanwhile, we developed a co-culture model of hippocampal tissue specimens and NSCs in vitro, to observe the effects of acupuncture on survival, proliferation and differentiation of grafted NSCs using flow cytometry. Results showed that acupuncture pre- and post-NSCs transplantation significantly improved senescence-induced cognitive dysfunction (P < 0.05); upregulated the expression of basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), and brain-derived neurotrophic factor (BDNF) (P < 0.05); and also increased the count of neuron-specific nuclear protein (NeuN)- and glial fibrillary acidic protein (GFAP)-positive cells (P < 0.05). Therapeutic acupuncture may regulate the cytokine levels associated with survival, proliferation, and differentiation of NSCs in hippocampal microenvironment, to promote the repair of damaged cells, resulting in improved cognitive performance in mice.

Brain-Derived Neurotrophic Factor Facilitates Functional Recovery from ALS-Cerebral Spinal Fluid-Induced Neurodegenerative Changes in the NSC-34 Motor Neuron Cell Line.

BACKGROUND: The survival of motor neurons is dependent upon neurotrophic factors both during childhood and adolescence and during adult life. In disease conditions, such as in patients with amyotrophic lateral sclerosis (ALS), the mRNA levels of trophic factors like brain-derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1), fibroblast growth factor-2 (FGF-2), and vascular endothelial growth factor are downregulated. This was replicated in our in vivo experimental system following the injection of cerebral spinal fluid (CSF) of sporadic ALS (ALS-CSF) patients. OBJECTIVE: To evaluate the protective role of BDNF in a model of sporadic ALS patients. METHODS: The expressions of endogenous BDNF, its receptor TrkB, the enzyme choline acetyl transferase (ChAT), and phosphorylated neurofilaments were studied in NSC-34 cells. The calcium-buffering and proapoptotic effects were assessed by calbindin-D28K and caspase-3 expression, respectively. RESULTS: ALS-CSF considerably depleted the endogenous BDNF protein, while its effect on IGF-1 and FGF-2 was inconsequential; this indirectly indicates a key role for BDNF in supporting motor neuronal survival. The exogenous supplementation of BDNF reversed autocrine expression; however, it may not be completely receptor mediated, as the TrkB levels were not restored. BDNF completely revived ChAT expression. It may inhibit apoptosis by restoring Ca2+ homeostasis, since caspase-3 and calbindin-D28K expression was back to normal. The organellar ultrastructural changes were only partially reversed. CONCLUSION: Our study provides evidence that BDNF supplementation ameliorates most but not all degenerative changes. The incomplete revival at the ultrastructural level signifies the requirement of factors other than BDNF for near-total protection of motor neurons, and, to an extent, it explains why only a partial success is achieved in clinical trials with BDNF in ALS patients.

Role of Hypothalamic VGF in Energy Balance and Metabolic Adaption to Environmental Enrichment in Mice.

Environmental enrichment (EE), a housing condition providing complex physical, social, and cognitive stimulation, leads to improved metabolic health and resistance to diet-induced obesity and cancer. One underlying mechanism is the activation of the hypothalamic-sympathoneural-adipocyte axis with hypothalamic brain-derived neurotrophic factor (BDNF) as the key mediator. VGF, a peptide precursor particularly abundant in the hypothalamus, was up-regulated by EE. Overexpressing BDNF or acute injection of BDNF protein to the hypothalamus up-regulated VGF, whereas suppressing BDNF signaling down-regulated VGF expression. Moreover, hypothalamic VGF expression was regulated by leptin, melanocortin receptor agonist, and food deprivation mostly paralleled to BDNF expression. Recombinant adeno-associated virus-mediated gene transfer of Cre recombinase to floxed VGF mice specifically decreased VGF expression in the hypothalamus. In contrast to the lean and hypermetabolic phenotype of homozygous germline VGF knockout mice, specific knockdown of hypothalamic VGF in male adult mice led to increased adiposity, decreased core body temperature, reduced energy expenditure, and impaired glucose tolerance, as well as disturbance of molecular features of brown and white adipose tissues without effects on food intake. However, VGF knockdown failed to block the EE-induced BDNF up-regulation or decrease of adiposity indicating a minor role of VGF in the hypothalamic-sympathoneural-adipocyte axis. Taken together, our results suggest hypothalamic VGF responds to environmental demands and plays an important role in energy balance and glycemic control likely acting in the melanocortin pathway downstream of BDNF.

Hyperactivation of BDNF-TrkB signaling cascades in human hypothalamic hamartoma (HH): a potential mechanism contributing to epileptogenesis.

AIMS: Although compelling evidence suggests that human hypothalamic hamartoma (HH) is intrinsically epileptogenic for gelastic seizures, the molecular mechanisms responsible for epileptogenesis within HH remain to be elucidated. The aim of this study was to test the hypothesis that hyperactivation of BDNF-TrkB signaling pathways in surgically resected HH tissue is a possible mechanism for downregulation of KCC2 expression, which in turn underlies GABA-mediated excitation within HH. METHODS: Activation of three major BDNF-TrkB signaling pathways including MAPKs, Akt, and PLCγ1 were evaluated in surgically resected HH tissue (n = 14) versus human hypothalamic control tissue (n = 8) using combined methodologies of biochemistry, molecular biology, cell biology, and electrophysiology. RESULTS: Our data show that compared with hypothalamic control tissue, in HH tissue, (i) activation of TrkB and expression of mature BDNF are elevated; (ii) MAPKs (including ERK1/2, p38, and JNK), Akt, and PLCγ1 are highly activated; (iii) KCC2 expression is downregulated; and (iv) pharmacological manipulation of TrkB signaling alters HH neuronal firing rate. CONCLUSION: Our findings suggest that multiple BDNF-TrkB signaling pathways are activated in HH. They act independently or collaboratively to downregulate KCC2 expression, which is the key component for GABA-mediated excitation associated with gelastic seizures.

BDNF modifies hippocampal KCC2 and NKCC1 expression in a temporal lobe epilepsy model.

Excitatory GABA actions, induced by altered expression of chloride transporters (KCC2/NKCC1), can contribute to seizure generation in temporal lobe epilepsy. In the present study, we evaluated whether BDNF administration can affect KCC2/NKCC1 expression, ictogenesis and behavioral alterations in this paradigm. Status epilepticus was induced in male rats with pilocarpine, followed by a treatment of either a single high dose or multiple injections of BDNF during the latent phase of temporal lobe epilepsy. Chloride transporters expression, spontaneous recurrent seizures, and hyperexcitability post-seizural behaviors were evaluated after treatment. NKCC1 protein expression was markedly upregulated, whereas that of KCC2 was significantly downregulated in epileptic hippocampi compared to intact controls. Application of BDNF (both single high dose and multiple injections) increased KCC2 expression in epileptic hippocampi, while NKCC1 expression was downregulated exclusively by the single high dose injection of BDNF. Development of spontaneous recurrent seizures was delayed but not prevented by the treatment, and hyperexcitability behaviors were ameliorated for a short period of time. To prevent GABA-A mediated depolarization and design appropriate treatment strategies for temporal lobe epilepsy, chloride transporters can be considered as a target. Future studies are warranted to investigate any possible therapeutic effects of BDNF via altering chloride transporters expression.

Green tea catechins potentiate the neuritogenic action of brain-derived neurotrophic factor: role of 67-kDa laminin receptor and hydrogen peroxide.

Delivery of optimal amounts of brain-derived neurotrophic factor (BDNF) to regions of the brain affected by neurodegenerative diseases is a daunting task. Using natural products with neuroprotective properties, such as green tea polyphenols, would be a highly useful complementary approach for inexpensive long-term treatment of these diseases. In this study, we used PC12(TrkB) cells which ectopically express TrkB, a high affinity receptor for BDNF. They differentiate and induce neurite outgrowth in response to BDNF. Using this model, we show for the first time that treatment with extremely low concentrations (<0.1 µg/ml) of unfractionated green tea polyphenols (GTPP) and low concentrations (<0.5 µM) of their active ingredient, epigallocatechin-3-gallate (EGCG), potentiated the neuritogenic ability of a low concentration (2 ng/ml) of BDNF. A synergistic interaction was observed between GTPP constituents, where epigallocatechin and epicatechin, both individually lacking this activity, promoted the action of EGCG. GTPP-induced potentiation of BDNF action required the cell-surface associated 67 kDa laminin receptor (67LR) to which EGCG binds with high affinity. A cell-permeable catalase abolished GTPP/EGCG-induced potentiation of BDNF action, suggesting the possible involvement of H2O2 in the potentiation. Consistently, exogenous sublethal concentrations of H2O2, added as a bolus dose (5 µM) or more effectively through a steady-state generation (1 µM), potentiated BDNF action. Collectively, these results suggest that EGCG, dependent on 67 LR and H2O2, potentiates the neuritogenic action of BDNF. Intriguingly, this effect requires only submicromolar concentrations of EGCG. This is significant as extremely low concentrations of polyphenols are believed to reach the brain after drinking green tea.