Brain-derived Neurotrophic Factor Gene Expression Research Articles

Isoflurane preconditioning effects on brain damage induced by electromagnetic pulse radiation through epigenetic modification of BDNF gene transcription.

The effects of electromagnetic pulse (EMP) radiation on cognitive impairment have attracted much attention, but the mechanism is still unclear. Regulation of brain-derived neurotrophic factor (BDNF) gene expression has been found to promote memory formation and neuronal survival. Isoflurane preconditioning (IP) was reported to have a neuroprotective effect. In this study, we verified the protective effect of IP against brain injury induced by EMP exposure and examined the relation of this effect with BDNF gene regulation. Twenty-four hours before EMP exposure, rats were pretreated with 2% inhaled isoflurane for 30 minutes. At 24 hours after EMP injury, the Morris water maze test was carried out. Meanwhile, the other rats were executed and their brain tissues were used for Nissl staining, qRT-PCR, western blot and chromatin immunoprecipitation. The Morris water maze results showed that 2% IP improved the spatial learning and memory ability of the rats. The Nissl staining results showed 2% of IP alleviated neuronal damage. Also, we detected the mRNA and protein expression of BDNF, and 2% IP significantly increased the expression of BDNF. We also found the expression level of histone deacetylase 2 (HDAC2) was increased and that EMP exposure significantly decreased H3 acetylation, while 2% IP reversed these phenomena, individually, BDNF transcription was activated, and neurogenesis after EMP exposure was alleviated. Our results suggested that 2% of IP alleviates cognitive impairment induced by EMP exposure in rats. Also, the sustained elevated level of BDNF gene transcription may be an essential mechanism for stimulating neurogenesis because of the increased level of HDAC2-dependent H3 acetylation.

Effects of maternal low-protein diet and spontaneous physical activity on the transcription of neurotrophic factors in the placenta and the brains of mothers and offspring rats.

Maternal protein restriction and physical activity can affect the interaction mother-placenta-fetus. This study quantified the gene expression of brain-derived neurotrophic factor (BDNF), neurothrophin 4, tyrosine kinase receptor B (TrkB/NTRK2), insulin-like growth factor (IGF-1), and insulin-like growth factor receptor (IGF-1r) in the different areas of mother's brain (hypothalamus, hippocampus, and cortex), placenta, and fetus' brain of rats. Female Wistar rats (n = 20) were housed in cages containing a running wheel for 4 weeks before gestation. According to the distance spontaneously traveled daily, rats were classified as inactive or active. During gestation, on continued access to the running wheel, active and inactive groups were randomized to receive normoprotein diet (18% protein) or a low-protein (LP) diet (8% protein). At day 20 of gestation, gene expression of neurotrophic factors was analyzed by quantitative polymerase chain reaction in different brain areas and the placenta. Dams submitted to a LP diet during gestation showed upregulation of IGF-1r and BDNF messenger RNA in the hypothalamus, IGF-1r and NTRK2 in the hippocampus, and BDNF, NTRK2, IGF-1 and IGF-1r in the cortex. In the placenta, there was a downregulation of IGF-1. In the brain of pups from mothers on LP diet, IGF-1r and NTRK2 were downregulated. Voluntary physical activity attenuated the effects of LP diet on IGF-1r in the hypothalamus, IGF-1r and NTRK2 in the hippocampus, IGF-1 in the placenta, and NTRK2 in the fetus' brain. In conclusion, both maternal protein restriction and spontaneous physical activity influence the gene expression of BDNF, NTRK2, IGF-1, and IGF-1r, with spontaneous physical activity being able to normalize in part the defects caused by protein restriction during pregnancy.

Neonatal Tactile Stimulation Alters Behaviors in Heterozygous Serotonin Transporter Male Rats: Role of the Amygdala.

The serotonin transporter (SERT) gene, especially the short allele of the human serotonin transporter linked polymorphic region (5-HTTLPR), has been associated with the development of stress-related neuropsychiatric disorders. In line, exposure to early life stress in SERT knockout animals contributes to anxiety- and depression-like behavior. However, there is a lack of investigation of how early-life exposure to beneficial stimuli, such as tactile stimulation (TS), affects later life behavior in these animals. In this study, we investigated the effect of TS on social, anxiety, and anhedonic behavior in heterozygous SERT knockouts rats and wild-type controls and its impact on gene expression in the basolateral amygdala. Heterozygous SERT+/– rats were submitted to TS during postnatal days 8–14, for 10 min per day. In adulthood, rats were assessed for social and affective behavior. Besides, brain-derived neurotrophic factor (Bdnf) gene expression and its isoforms, components of glutamatergic and GABAergic systems as well as glucocorticoid-responsive genes were measured in the basolateral amygdala. We found that exposure to neonatal TS improved social and affective behavior in SERT+/– animals compared to naïve SERT+/– animals and was normalized to the level of naïve SERT+/+ animals. At the molecular level, we observed that TS per se affected Bdnf, the glucocorticoid-responsive genes Nr4a1, Gadd45β, the co-chaperone Fkbp5 as well as glutamatergic and GABAergic gene expression markers including the enzyme Gad67, the vesicular GABA transporter, and the vesicular glutamate transporter genes. Our results suggest that exposure of SERT+/– rats to neonatal TS can normalize their phenotype in adulthood and that TS per se alters the expression of plasticity and stress-related genes in the basolateral amygdala. These findings demonstrate the potential effect of a supportive stimulus in SERT rodents, which are more susceptible to develop psychiatric disorders.

Protective effect of Lactobacillus salivarius Li01 on thioacetamide-induced acute liver injury and hyperammonaemia.

The gut microbiota plays pivotal roles in liver disease onset and progression. The protective effects of Lactobacillus salivarius Li01 on liver diseases have been reported. In this study, we aimed to detect the protective effect of L. salivarius Li01 on thioacetamide (TAA)-induced acute liver injury and hyperammonaemia. C57BL/6 mice were separated into three groups and given a gavage of L. salivarius Li01 or phosphate-buffered saline for 7days. Acute liver injury and hyperammonaemia were induced with an intraperitoneal TAA injection. L. salivarius Li01 decreased mortality and serum transaminase levels and improved histological liver damage caused by TAA. Serum inflammatory cytokine and chemokine and lipopolysaccharide-binding protein (LBP) concentrations, nuclear factor κB (NFκB) pathway activation and macrophage and neutrophil infiltration into the liver were significantly alleviated by L. salivarius Li01. L. salivarius Li01 also reinforced gut barrier and reshaped the perturbed gut microbiota by upregulating Bacteroidetes and Akkermansia richness and downregulating Proteobacteria, Ruminococcaceae_UCG_014 and Helicobacter richness. Plasma and faecal ammonia levels declined noticeably in the Li01 group, accompanied by improvements in cognitive function, neuro-inflammation and relative brain-derived neurotrophic factor (BDNF) gene expression. Our results indicated that L. salivarius Li01 could be considered a potential probiotic in acute liver injury and hepatic encephalopathy (HE).

Maternal high-fat diet stimulates proinflammatory pathway and increases the expression of Tryptophan Hydroxylase 2 (TPH2) and brain-derived neurotrophic factor (BDNF) in adolescent mice hippocampus

Maternal high-fat diet (HFD) consumption can promote a systemic inflammatory condition that may impair the offspring brain development, damaging memory and learning, when it reaches the hippocampus. This study aims to evaluate maternal HFD effects, during pregnancy and lactation, upon dams/mice offspring nutritional status, protein and gene expression of inflammatory pathway (JNK, pJNK and TNF-α), serotonin system molecules (Tryptophan Hydroxylase 2 (TPH2), key-enzyme of serotonin synthesis, serotonin transporter (SERT); 5-HT1A serotonergic receptor (5-HT1A)) and brain derived neurotrophic factor (BDNF) on recently weaned mice offspring hippocampus. Female Swiss mice were fed a control diet (CD, 11,5% fat) or a HFD (45.0% fat) from pre-mating to lactation. After weaning, the offspring received CD up to 28 post-natal days (PND28). Body weight and visceral adiposity (retroperitoneal and gonadal adipose tissue) of dams and offspring were measured. After euthanasia, the offspring hippocampus was dissected for evaluations of BDNF, inflammatory pathway and serotonergic system molecules protein and gene expression, through the techniques of Western Blotting, RTqPCR and ELISA. Our findings show that, during pregnancy, HFD-dams and HFD-offspring exhibited an increase in body weight gain and visceral adipose tissue compared to control animals. The hippocampus of HFD-offspring showed increased protein expression of TPH2, BDNF, pJNK and increased mRNA levels of TNF-α. However, the TPH2 increase in HFD-offspring did not alter hippocampal serotonin levels quantified through ELISA. Maternal HFD promoted an obesity phenotype in its offspring with increased body weight and visceral adiposity, increased protein and gene expression of the pro-inflammatory proteins pJNK and TNF-α. These changes were accompanied by increased TPH2 and BDNF protein expression. Thus, our findings show that maternal HFD during gestation and lactation increased pJNK and TNF-α expression in their offspring hippocampus indicating a pro-inflammatory state, with increased BDNF expression and alterations in its serotonergic system reflected by increased TPH2 expression.

Effects of Swimming Training and Royal Jelly on BDNF and NGF Gene Expression in Hippocampus Tissue of Rats with Alzheimer’s Disease

Background: Alzheimer’s disease (AD) is an age-related neurodegenerative disorder. Evidence from neuropathological studies indicates that the levels of neurotrophins brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) are compromised in AD. Objectives: The present study aimed to review the effects of swimming training and royal jelly (RJ) on BDNF and NGF gene expression in the hippocampus tissue of rats with AD. Methods: In the present experimental study, 25 rats with AD were divided into five groups, including (1) control, (2) sham, (3) RJ, (4) training, and (5) training with RJ. Five healthy rats were selected as the healthy control group to examine the effect of AD induction by 8 mg/kg trimethyltin chloride (TMT) intra-peritoneally on BDNF and NGF. During eight weeks, groups 3 and 5 received 100 mg/kg RJ daily intra-peritoneally, and groups 4 and 5 swam in a rat swimming tank three sessions per week. One-way ANOVA with Tukey’s post hoc test was used for data analysis in SPSS 20 software (P < 0.05). Results: The induction of AD by TMT had a significant effect on the reduction of BDNF (P = 0.001) and NGF (P = 0.001). However, RJ had a significant effect on the increase of NGF (P = 0.03). Nevertheless, RJ (P = 0.99), training (P = 0.99), and training with RJ (P = 0.94) had no significant effect on BDNF and training (P = 0.99) and training with RJ (P = 0.97) had no significant effect on NGF. Conclusions: It appears that RJ has a significant effect on the increase of NGF gene expression in the hippocampus tissue of rats with AD. Nevertheless, RJ consumption simultaneously with swimming training has no significant effect on BDNF and NGF.

The Effect of Endurance Exercise Training on the Expression of Brain Derived Neurotrophic Factor (BDNF) and Nerve Growth Factor (NGF) Genes of the Cerebellum in Diabetic Rat

Objective: Few studies have been conducted on variations of the central nervous system of diabetic patients and much fewer investigations done on the cerebellum of diabetes patients. The current research aims to investigate the effect of endurance training on neurotrophic factors affecting the cerebellum in the diabetic rat. Materials and Methods: This study is experimental.Twenty Wistar rat were randomly allocated in four groups including: (1) control (n=5), (2) diabetic exercise (n=5), (3) healthy-control (n=5), (4) and exercise-healthy (n=5). Diabetes were induced by intraperitoneal Streptozotocin injection. The endurance exercise training was performed at moderate intensity for six weeks. Expression of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) genes were measured using the Real-Time PCR method in the cerebellum of the rat. Two-way ANOVA test was used for comparing the means of expression of genes between groups. All statistical analyses were done using SPSS 22 software. Results: A significant increase was observed in the expression of NGF (from 1.03±0.11 to 1.61±0.24; P-value≤ 0.05) and BDNF (from 1.59±0.06 to 3.24±0.46; P-value≤ 0.05) genes in male rats with experimental diabetes and healthy subjects after six weeks endurance training. Conclusion: Endurance training may be helpful for diabetic patients by increasing the neurotrophic factors and thereby preventing diabetes-related neural complications.

SUN-235 Deficient Fear Extinction in PRKAR1A-Defective Mice

Background: The role of the cAMP/PKA signaling in molecular pathways involved in fear memory is well established: PKA is required for fear memory formation and is a constraint for fear extinction. Previously we reported that a Prkar1a heterozygote (HZ) mouse that was developed in our lab to investigate Carney complex (CNC), the disease caused by PRKAR1A mutations, showed brain region-specific increased PKA activity that was associated with anxiety-like behavioral phenotype and threat bias (Keil, 2010, 2013). We hypothesized that Prkar1a+/- (HZ) mice would have deficits in fear extinction behavior. Brain derived neurotrophic factor (BDNF) has a critical role in formation of fear memory and its transcription is regulated by PKA/CREB. A mouse model with down regulation of PKA provides an opportunity for the first time to investigate the effect of altered PKA signaling on fear conditioning and extinction.Method: Fear conditioning, fear extinction learning, and fear extinction recall were tested in adult male HZ and wild-type (WT) mice as follows: fear conditioning training followed 24hr later by extinction training (new context), then 24hr later by extinction recall training. Percentage of time freezing was used to assess conditioned fear response. We measured BDNF gene expression in brain regions after completion of extinction recall training.Results: As expected, fear conditioning (learning) behavior was similar in HZ and WT mice. However, HZ mice showed a significant deficit in the early phase of fear extinction learning compared to WT. There was no difference in extinction recall between genotypes. Alterations in BDNF gene expression in the prefrontal cortex and amygdala was associated with deficit in fear extinction.Conclusion: Mice with a downregulation of Prkar1a gene demonstrate intact fear conditioning but impaired fear extinction learning, consistent with prior studies that report that PKA inhibition is necessary to facilitate extinction learning. Prkar1a+/- mice provide a valuable model to investigate impaired fear extinction to identify mechanisms for therapeutic targets for anxiety and trauma-related disorders.

BDNF‐Induced Arc Expression Was Enhanced by PIC in Neuronal Cells Treated with High Glucose and Amyloid Beta

ObjectivesHyperglycemia has been shown to be associated with Alzheimer’s disease and impairment of cognitive function. Alzheimer’s disease is characterized by the excessive formation of amyloid‐beta (Aβ) and neurofibrillary tangle. Aβ is generated by cutting amyloid precursor protein (APP) by β‐secretase (BACE1) and γ‐secretase. Brain‐derived neurotrophic factor (BDNF) is the important molecule that is involved in synaptic plasticity and neuronal survival. BDNF binds to trkB receptor and activates PI3K/Akt/mTOR pathway, and it increases synaptic efficacy by inducing expression of activity‐regulated cytoskeleton‐associated protein (Arc) which is the marker of plastic changes of the brain. Suppression of BDNF is related to the pathogenesis of Alzheimer’s disease. Piceatannol (PIC) is a polyphenolic compound that has similar structure to resveratrol having neuroprotective efficacy. Thus, we investigated the effects of PIC treatment on amyloidogenesis and BDNF signaling in neuronal cells treated with high glucose and Aβ.MethodsThe SH‐SY5Y cells were treated with 25 mM D‐glucose and 10 μM Aβ in order to induce the cell culture model of high glucose‐induced Alzheimer’s disease. And then, cells were treated with 20 μM PIC for 24 h. Relative gene expression levels of amyloidogenesis‐ and BDNF signaling‐related markers were analyzed. Aβ concentrations were measured by ELISA to examine whether PIC alters the levels of Aβ deposit. One‐way analysis of variance (ANOVA) was performed to assign statistical significance followed by Fisher’s Least Significant Difference (LSD) post‐hoc analysis using SPSS software (IBM SPSS Statistics 24).ResultsIn the condition of high glucose‐induced Alzheimer’s disease, PIC treatment significantly increased the relative gene expression of BACE1 (P = 0.003). The presenilin 1 expression tended to rise up by PIC in this condition. The concentrations of Aβ were significantly lower in cells treated with high glucose, Aβ, and PIC compared with those without PIC (P < 0.001). The relative expression levels of BDNF in high glucose group treated with PIC tended to be higher than those without PIC. PIC treatment significantly increased the relative gene expression of BDNF in cells treated with high glucose and Aβ (P = 0.002). The Arc expression was also significantly increased by PIC in those cells (P = 0.038).ConclusionsWe found that PIC improves the pathological alterations by high glucose and Aβ, which is accompanied by decreased Aβ formation and upregulation of BDNF and Arc expressions in high glucose and Aβ‐treated neuronal cells. Therefore, PIC may have a therapeutic effect on the pathological conditions of hyperglycemia‐induced Alzheimer’s disease.

Myrtus communis subsp. communis improved cognitive functions in ovariectomized diabetic rats.

The purpose of this study was to investigate the possible effects of Myrtus communis subsp. communis (MC) on cognitive impairment in ovariectomized diabetic rats. Female Sprague-Dawley rats were divided into 5 groups consisting of 15 rats each; Control (C), Diabetes (D), Ovariectomy and diabetes (OVX+D), Ovariectomy, diabetes and donepezil (OVX+D+Don), Ovariectomy, diabetes and Myrtus communis subsp. communis (OVX+D+MC). Blood glucose measurements were made at the beginning and end of the experiments. The animals underwent the novel object recognition test (NORT) and their performance was evaluated. In hippocampal tissues; amyloid beta (Aβ) and neprilysin levels, acetylcholinesterase (AChE), and choline acetyltransferase (ChAT) activities, polysialylated neural cell adhesion molecule (PSA-NCAM), α7 subunit of neuronal nicotinic acetylcholine receptor (α7-nAChR) and brain derived neurotrophic factor (BDNF) gene expressions were examined. Animals with ovariectomy and diabetes showed increased levels of blood glucose, AChE activity and Aβ levels, and decreased neprilysin levels, ChAT activity, α7-nAChR, PSA-NCAM and BDNF gene expressions in parallel with a decrease in NORT performance score. On the other hand, in the MC-treated OVX+D group, there was a significant decrease observed in blood glucose levels and AChE activities while there was improvement in NORT performances and an increase in hippocampal ChAT activity, neprilysin levels, α7-nAChR, PSA-NCAM and BDNF expressions. These results suggest that MC extract could improve cognitive and neuronal functions with its anticholinesterase and antihyperglycemic properties.

Protection of the Retinal Ganglion Cells: Intravitreal Injection of Resveratrol in Mouse Model of Ocular Hypertension.

PurposeTo investigate the efficacy of intravitreal administration of resveratrol (RSV) in a microbead-induced high intraocular pressure (IOP) murine model for glaucoma.MethodsExperiments were performed using adult C57BL/6JJcl mice. Polystyrene microbeads were injected into the anterior chamber to induce IOP elevation. Retinal flat-mounts and sections were assessed by immunohistochemistry to detect the expression of reactive oxygen species and acetyl-p53 in retinal ganglion cells (RGCs), brain-derived neurotrophic factor (BDNF) in Müller glial cells (MGCs), and the receptor tropomyosin receptor kinase B (TrkB) in RGCs. Light cycler real-time PCR was also used for confirming gene expression of BDNF in primary cultured MGCs exposed to RSV.ResultsMicrobeads induced high IOP followed by RGC death and axon loss. Administration of RSV rescued RGCs via decreased reactive oxygen species generation and acetyl-p53 expression in RGCs and upregulated BDNF in MGCs and TrkB expression in RGCs, which exhibited a strong cytoprotective action against cell death through multiple pathways under high IOP.ConclusionsOur data suggest that administration of RSV may delay the progress of visual dysfunction during glaucoma and may therefore have therapeutic potential.

Identifying inducers of BDNF gene expression from pharmacologically validated compounds; antipyretic drug dipyrone increases BDNF mRNA in neurons

Low levels of brain-derived neurotrophic factor (BDNF), a key regulator of synaptic plasticity, are associated with neurological diseases, including depression and Alzheimer’s disease. Therefore, BDNF is a drug target for these diseases. Here we screened for inducers of neuronal Bdnf expression from a pharmacologically validated compound library using our recently developed screening assay based on luciferase activity in cultured cortical neurons. We identified 18 pharmacologically validated compounds, most of which were inferred to induce Bdnf expression by their validated pharmacological actions, such as Gs-coupled receptor activation or neuronal excitation. Unexpectedly, the screening assay identified the antipyretic drug, dipyrone, to increase Bdnf expression. Dipyrone induced endogenous Bdnf expression by Ca2+ influx evoked via L-type voltage-dependent Ca2+ channels and the N-methyl-d-aspartate receptor, indicating that dipyrone induced activity-regulated Bdnf expression in neurons. However, dipyrone-induced Bdnf expression is independent of validated pharmacological effects. Although our screening assay is difficult to reveal how active compounds induce Bdnf expression, this method is convenient to identify inducers of Bdnf expression in primary neurons. Our screening assay evaluated neuronal BDNF induction and can be used to screen for drug re-positioning, as well as novel candidate drugs, for neurological diseases that have low levels of BDNF in the brain.

Combination of olfactory ensheathing cells and human umbilical cord mesenchymal stem cell-derived exosomes promotes sciatic nerve regeneration.

Olfactory ensheathing cells (OECs) are promising seed cells for nerve regeneration. However, their application is limited by the hypoxic environment usually present at the site of injury. Exosomes derived from human umbilical cord mesenchymal stem cells have the potential to regulate the pathological processes that occur in response to hypoxia. The ability of OECs to migrate is unknown, especially in hypoxic conditions, and the effect of OECs combined with exosomes on peripheral nerve repair is not clear. Better understanding of these issues will enable the potential of OECs for the treatment of nerve injury to be addressed. In this study, OECs were acquired from the olfactory bulb of Sprague Dawley rats. Human umbilical cord mesenchymal stem cell-derived exosomes (0-400 μg/mL) were cultured with OECs for 12-48 hours. After culture with 400 μg/mL exosomes for 24 hours, the viability and proliferation of OECs were significantly increased. We observed changes to OECs subjected to hypoxia for 24 hours and treatment with exosomes. Exosomes significantly promoted the survival and migration of OECs in hypoxic conditions, and effectively increased brain-derived neurotrophic factor gene expression, protein levels and secretion. Finally, using a 12 mm left sciatic nerve defect rat model, we confirmed that OECs and exosomes can synergistically promote motor and sensory function of the injured sciatic nerve. These findings show that application of OECs and exosomes can promote nerve regeneration and functional recovery. This study was approved by the Institutional Ethical Committee of the Air Force Medical University, China (approval No. IACUC-20181004) on October 7, 2018; and collection and use of human umbilical cord specimens was approved by the Ethics Committee of the Linyi People's Hospital, China (approval No. 30054) on May 20, 2019.

Effect of vitamin D supplementation on CREB-TrkB-BDNF pathway in the hippocampus of diabetic rats.

Objective(s):Cyclic AMP (adenosine monophosphate) response element-binding protein (CREB) and Brain-derived neurotrophic factor (BDNF) are reported to broadly involve in learning capacity and memory. BDNF exerts its functions via tropomyosin receptor kinase B (TrkB). BDNF transcription is regulated by stimulating CREB phosphorylation. The CREB-TrkB-BDNF pathway is reported to be affected by diabetes, which may contribute to its cognitive deficits. This study was conducted to investigate the effect of vitamin D supplementation on the hippocampal fraction of this pathway in an animal model of type-1 diabetes mellitus (T1DM). Materials and Methods:Thirty-six adult male Sprague-Dawley rats were randomly divided into 4 groups as follows: Group 1: normal healthy rats (n=8); group 2: normal healthy rats receiving sesame oil supplementation as placebo (n=8); Group 3: diabetic rats receiving sesame oil (n=10); and Group 4: diabetic rats treated with 4300 IU/kg/week vitamin D dissolved in sesame oil (n=10). Diabetes was induced by intraperitoneal (IP) injection of streptozotocin. Blood and hippocampal samples were acquired at the end of the experiment. RNA was extracted from the hippocampus, and real-time PCR (polymerase chain reaction) was performed for BDNF and TrkB gene expression. Results:Administration of vitamin D (4300 IU/kg/week) in a T1DM animal model increased CREB phosphorylation in the hippocampus, but the serum and hippocampal BDNF levels and TrkB and BDNF gene expression did not change significantly.Conclusion:Vitamin D increased hippocampal CREB phosphorylation in a T1DM animal model. Our findings showed that vitamin D might be protective against central nervous system complications in diabetes. However, future studies are warranted.

Self-assembling peptide hydrogels functionalized with LN- and BDNF- mimicking epitopes synergistically enhance peripheral nerve regeneration.

The regenerative capacity of the peripheral nervous system is closely related to the role that Schwann cells (SCs) play in construction of the basement membrane containing multiple extracellular matrix proteins and secretion of neurotrophic factors, including laminin (LN) and brain-derived neurotrophic factor (BDNF). Here, we developed a self-assembling peptide (SAP) nanofiber hydrogel based on self-assembling backbone Ac-(RADA)4-NH2 (RAD) dual-functionalized with laminin-derived motif IKVAV (IKV) and a BDNF-mimetic peptide epitope RGIDKRHWNSQ (RGI) for peripheral nerve regeneration, with the hydrogel providing a three-dimensional (3D) microenvironment for SCs and neurites.Methods: Circular dichroism (CD), atomic force microscopy (AFM), and scanning electron microscopy (SEM) were used to characterize the secondary structures, microscopic structures, and morphologies of self-assembling nanofiber hydrogels. Then the SC adhesion, myelination and neurotrophin secretion were evaluated on the hydrogels. Finally, the SAP hydrogels were injected into hollow chitosan tubes to bridge a 10-mm-long sciatic nerve defect in rats, and in vivo gene expression at 1 week, axonal regeneration, target muscular re-innervation, and functional recovery at 12 weeks were assessed.Results: The bioactive peptide motifs were covalently linked to the C-terminal of the self-assembling peptide and the functionalized peptides could form well-defined nanofibrous hydrogels capable of providing a 3D microenvironment similar to native extracellular matrix. SCs displayed improved cell adhesion on hydrogels with both IKV and RGI, accompanied by increased cell spreading and elongation relative to other groups. RSCs cultured on hydrogels with IKV and RGI showed enhanced gene expression of NGF, BDNF, CNTF, PMP22 and NRP2, and decreased gene expression of NCAM compared with those cultured on other three groups after a 7-day incubation. Additionally, the secretion of NGF, BDNF, and CNTF of RSCs was significantly improved on dual-functionalized peptide hydrogels after 3 days. At 1 week after implantation, the expressions of neurotrophin and myelin-related genes in the nerve grafts in SAP and Autograft groups were higher than that in Hollow group, and the expression of S100 in groups containing both IKV and RGI was significantly higher than that in groups containing either IKV or RGI hydrogels, suggesting enhanced SC proliferation. The morphometric parameters of the regenerated nerves, their electrophysiological performance, the innervated muscle weight and remodeling of muscle fibers, and motor function showed that RAD/IKV/RGI and RAD/IKV-GG-RGI hydrogels could markedly improve axonal regeneration with enhanced re-myelination and motor functional recovery through the synergetic effect of IKV and RGI functional motifs.Conclusions: We found that the dual-functionalized SAP hydrogels promoted RSC adhesion, myelination, and neurotrophin secretion in vitro and successfully bridged a 10-mm gap representing a sciatic nerve defect in rats in vivo. The results demonstrated the synergistic effect of IKVAV and RGI on axonal regrowth and function recovery after peripheral nerve injury.

Acute stress in adolescence vs early adulthood following selective deletion of dysbindin-1A: Effects on anxiety, cognition and other schizophrenia-related phenotypes

As exposure to stress has been linked to the onset and maintenance of psychotic illness, its pathogenesis may involve environmental stressors interacting with genetic vulnerability. To establish whether acute stress interacts with a targeted mutation of the gene encoding the neurodevelopmental factor dystrobrevin-binding protein 1 (DTNBP1), resulting in a specific loss of the isoform dysbindin-1A, to influence schizophrenia-relevant phenotypes in mice during adolescence and adulthood. Male and female mice with a heterozygous or homozygous deletion of DTNBP1 were assessed in the open field test following acute restraint stress in adolescence (Day 35) and young adulthood (Day 60-70). Effects of acute restraint stress on memory retention in the novel object recognition test was also assessed in adulthood. Baseline corticosterone was measured in serum samples and, brain-derived neurotrophic factor (BDNF), glucocorticoid and mineralocorticoid receptor gene expression levels were measured in the hippocampus of adult mice. In the open field, deletion of dysbindin-1A induced hyperactivity and attenuated the action of stress to reduce hyperactivity in adolescence but not in adulthood; in females deletion of dysbindin-1A attenuated the effect of acute stress to increase anxiety-related behaviour in adolescence but not in adulthood. In the novel object recognition test, deletion of dysbindin-1A impaired memory and also revealed an increase in anxiety-related behaviour and a decrease in hippocampal BDNF gene expression in males. These data suggest that deletion of dysbindin-1A influences behaviours related to schizophrenia and anxiety more robustly in adolescence than in adulthood and that dysbindin-1A influences stress-related responses in a sex-dependent manner.

NGF, BDNF and Arc mRNA Expression in the Hippocampus of Rats After Administration of Morphine.

Morphine can influence immediate early genes (IEG) of activity-regulated cytoskeletal-associated protein (Arc) and brain-derived neurotrophic factor (BDNF) which are activated in response to physiological stimuli during learning, as well as the nerve growth factor (NGF) gene which increases the expression of several IEGs for memory formation. The purpose of the current study was first to evaluate the effect of acute (1-day) and subchronic (15-days) morphine administration on memory retrieval of rats and second to determine the hippocampal expression of NGF, BDNF and Arc genes as potential contributors in the observed effects in each setting. The effects of morphine (intraperitoneal, 10, 15 and 20mg/kg) on memory function and gene expression were assessed using inhibitory avoidance test and real-time polymerase chain reaction, respectively. We found that a single dose of morphine at the highest dose of 20mg/kg decreases the post-training step-through-latency, while repeated administration of the same dose for 15 successive days increases this indicator of memory retrieval. We did not detect a significant change in the hippocampal expression of Arc, BDNF or NGF genes after a single episode of morphine treatment. However, subchronic morphine administration (15 and 20mg/kg) increased the expression of Arc and BDNF genes in a dose dependent manner. A higher mRNA expression for the NGF was observed at the higher dose of 20mg/kg. We hypothesize that the subchronic effects were morphine-induced behavioral sensitization which may have been enhanced through increased hippocampal Arc expression.

Conditioned taste aversion memory extinction temporally induces insular cortical BDNF release and inhibits neuronal apoptosis.

BackgroundMemory extinction has been reported to be related to psychiatric disorders, such as post-traumatic stress disorder (PTSD). Secretion and synthesis of brain-derived neurotrophic factor (BDNF) have been shown to temporally regulate various memory processes via activation of tropomyosin-related kinase B (TrkB) receptors. However, whether memory extinction induces the synthesis and secretion of BDNF on the basis of its localization is not understood. In this study, we aim to investigate activity-dependent BDNF secretion and synthesis in the insular cortex (IC) in the setting of conditioned taste aversion (CTA) memory extinction.Materials and methodsRats were subjected to CTA memory extinction and BDNF antibody (or the equal volume of vehicle) was microinjected into the IC immediately after the extinction testing. Real-time polymerase chain reaction and in situ hybridization were used to detect the gene expression of BDNF, NGF and NT4. The protein levels of BDNF were determined through the enzyme-linked immunosorbent assay. In addition, the levels of phosphorylated TrkB normalized to total TrkB were evaluated using immunoprecipitation and immunoblotting. c-Fos, total extracellular signal-regulated kinase (Erk), phosphorylated Erk, and apoptosis-related protein (caspase-3), were detected by Western blotting.ResultsWe found that blocking BDNF signaling within the IC disrupts CTA extinction, suggesting that BDNF signaling in the IC is necessary for CTA extinction. Increased expression levels of c-Fos indicate the induced neuronal activity in the IC during CTA extinction. In addition, temporal changes in the gene expression and protein levels of BDNF in the IC were noted during extinction. Moreover, we found that phosphorylation of TrkB increased prior to the enhanced BDNF expression, suggesting that CTA extinction induces rapid activity-dependent BDNF secretion in the IC. Finally, we found decreased expression of caspase-3 in the IC after CTA extinction.ConclusionThese results demonstrate that CTA memory extinction temporally induces the release and synthesis of BDNF in the IC and inhibits neuronal apoptosis.

Brain-derived neurotrophic factor (BDNF) and TrkB hippocampal gene expression are putative predictors of neuritic plaque and neurofibrillary tangle pathology

IntroductionDownregulation of brain-derived neurotrophic factor (BDNF) and its cognate neurotrophin receptor, TrkB, were observed during the progression of dementia, but whether the Alzheimer's disease (AD) pathological lesions diffuse plaques, (DPs), neuritic plaques (NPs), and neurofibrillary tangles (NFTs) are related to this alteration remains to be clarified. MethodsNegative binomial (NB) regressions were performed using gene expression data accrued from a single population of CA1 pyramidal neurons and regional hippocampal dissections obtained from participants in the Rush Religious Orders Study (RROS). ResultsDownregulation of Bdnf is independently associated with increased entorhinal cortex NPs. Downregulation of TrkB is independently associated with increased entorhinal cortex NFTs and CA1 NPs during the progression of AD. DiscussionResults indicate that BDNF and TrkB dysregulation contribute to AD neuropathology, most notably hippocampal NPs and NFTs. These data suggest attenuating BDNF/TrkB signaling deficits either at the level of BDNF, TrkB, or downstream of TrkB signaling may abrogate NPs and/or NFTs.

Assessment of genes involved in behavior, learning, memory, and synaptic plasticity following status epilepticus in rats

ObjectiveIn this study, it was aimed to evaluate cognitive and behavioral changes after status epilepticus (SE) induced by pentylenetetrazole in immature rats via Morris water maze and open-field area tests and to assess alterations in expression of 84 key genes involved in synaptic plasticity after SE. MethodThe study was conducted on 30 immature rats (12-days old). The rats were assigned into groups as control and experiment (SE) groups. The SE was induced by pentylenetetrazole in 12-days old rats. In addition, experiment group was divided into two groups as mature (n = 8) and immature SE (n = 8) subgroups. Again, the control group was divided into two groups as mature (n = 7) and immature control (n = 7) subgroups. Hippocampal tissue samples were prepared, and expression of 84 key genes involved in synaptic plasticity was assessed in Genome and Stem Cell Center of Erciyes University before behavioral tests in immature rats (22-days old) and after open-filed area and Morris water maze tests in mature rats (72-days old) in both experiment and control groups. ResultsNo significant difference was detected in behavioral tests assessing spatial memory and learning among groups. Significant differences were detected, ARC (activity-regulated cytoskeleton-associated protein), BDNF (brain-derived neurotrophic factor), MAPK1 (mitogen-activated protein kinase 1), NR4A1 (nuclear receptor subfamily 4 group A member 1), PPP3CA (protein phosphatase 3 catalytic subunit alpha), RGS2 (regulator of G protein signaling 2), and TNF (tumor necrosis factor) gene expressions between control and experiment groups in immature rats whereas in ADCY8 (adenylate cyclase 8), BDNF (brain-derived neurotrophic factor), EGR4 (early growth response 4), and KIF17 (kinesin family member 17) gene expressions between control and experiment groups in mature rats. DiscussionIn this study, differences detected in gene expressions of synaptic plasticity after SE indicate in which steps of synaptic plasticity may be problematic in epileptogenesis. The gene expressions in this study may be considered as potential biomarkers; however, epileptogenesis is a dynamic process and cannot be explained through a single mechanism. Future studies on epileptogenesis and studies specifically designed to evaluate genes detected in our study will further elucidate synaptic plasticity in epilepsy and epileptogenesis.