Prediction of the Development of Depression in Patients with Autoimmune Thyroiditis and Hypothyroidism

BACKGROUND: Hypothyroidism is frequently accompanied by depression symptoms, whereas depression is considered the most common mental disorder. AIM: It is crucial to analyze the associations of the brain neurotrophic factor (BDNF) gene polymorphism (rs6265), the VDR gene polymorphism (rs2228570), and the NMDA gene polymorphism (rs4880213) with the depression in patients with autoimmune thyroiditis and hypothyroidism in the Western Ukrainian population and predict the development of depressive disorders in these patients. METHODS: The study involved a total of 153 patients with various forms of thyroid pathology. BDNF levels in the sera of the patients and healthy individuals were quantified using enzyme-linked immunosorbent assay with highly sensitive Human BDNF ELISA Kit (Elabscience®, United States, Catalog No: E-EL-H0010) on E.I.A. Reader Sirio S (Seac, Italy). Genotyping of the VDR (rs2228570), BDNF (rs6265), and NMDA (rs4880213) gene polymorphism using TaqMan probes and TaqMan Genotyping Master Mix (4371355) on CFX96™Real-Time Polymerase chain reaction (PCR) Detection System (Bio-Rad Laboratories, Inc., USA). PCR for TaqMan genotyping was carried out according to the kit instructions (Applied Biosystems, USA). We used the Student’s t-test, ANOVA, Pearson’s Chi-square test, ROC-analysis, odds ratio test, relative odds ratio test. The odds ratio and 95% confidence interval were computed by binary logistic regression. RESULTS: When comparing the presence of depression on the Hamilton scale, statistically significant differences were found depending on BDNF gene polymorphism (rs6265) (p < 0.001), and non-statistically noticeable differences were detected depending on the VDR gene polymorphism (rs2228570) and NMDA gene polymorphism (rs4880213). Our study revealed a marked inverse connection between depression and BDNF levels (p < 0.001) and a reverse moderate correlation between depression and fT4 (p < 0.001) and 25-OH Vitamin D levels (p < 0.001). In addition, we identified a direct moderate correlation between pronounced levels of depression and thyroid-stimulating hormone (TSH) in the blood (p < 0.001). CONCLUSIONS: Indicators such as BDNF, TSH, fT4, anti-TPO, and 25-OH Vitamin D levels were found to be prognostically significant criteria for the risk of developing depression.

Necrostatin-1 Against Sevoflurane-Induced Cognitive Dysfunction Involves Activation of BDNF/TrkB Pathway and Inhibition of Necroptosis in Aged Rats

Postoperative cognitive dysfunction (POCD) induced by anesthesia or surgery has become a common complication in the aged population. Sevoflurane, a clinical inhalation anesthetic, could stimulate calcium overload and necroptosis to POCD. In addition, necroptosis inhibitor necrostatin-1 (Nec-1) alleviated cognitive impairment caused by multiple causes, including postoperative cognitive impairment. However, whether Nec-1 exerts a neuroprotective effect on POCD via calcium and necroptosis remains unclear. We anesthetized Sprague-Dawley rats with sevoflurane to construct the POCD model and to explore the mechanism underlying neuroprotective effects of Nec-1 in POCD. Rats were treated with Nec-1 (6.25 mg/kg) 1 h prior to anesthesia. Open field test and Morris water maze were employed to detect the cognitive function. In this study, rats exposed to sevoflurane displayed cognitive dysfunction without changes in spontaneous activity; however, the sevoflurane-induced POCD could be relieved by Nec-1 pretreatment. Nec-1 decreased sevoflurane-induced calcium overload and calpain activity in the hippocampus. In addition, Nec-1 alleviated the expression of p-RIPK1, RIPK1, p-RIPK3, RIPK3, p-MLKL and MLKL. Furthermore, Nec-1 remarkably increased BDNF and p-TrkB/TrkB expression in the hippocampus of aged rats. Ultimately, our research manifests evidence that Nec-1 may play a neuroprotective role against sevoflurane-induced cognitive impairment via the increase of BDNF/TrkB and suppression of necroptosis-related pathway.

Schizophrenia is defined by cell-specific neuropathology and multiple neurodevelopmental mechanisms in patient-derived cerebral organoids

Due to an inability to ethically access developing human brain tissue as well as identify prospective cases, early-arising neurodevelopmental and cell-specific signatures of Schizophrenia (Scz) have remained unknown and thus undefined. To overcome these challenges, we utilized patient-derived induced pluripotent stem cells (iPSCs) to generate 3D cerebral organoids to model neuropathology of Scz during this critical period. We discovered that Scz organoids exhibited ventricular neuropathology resulting in altered progenitor survival and disrupted neurogenesis. This ultimately yielded fewer neurons within developing cortical fields of Scz organoids. Single-cell sequencing revealed that Scz progenitors were specifically depleted of neuronal programming factors leading to a remodeling of cell-lineages, altered differentiation trajectories, and distorted cortical cell-type diversity. While Scz organoids were similar in their macromolecular diversity to organoids generated from healthy controls (Ctrls), four GWAS factors (PTN, COMT, PLCL1, and PODXL) and peptide fragments belonging to the POU-domain transcription factor family (e.g., POU3F2/BRN2) were altered. This revealed that Scz organoids principally differed not in their proteomic diversity, but specifically in their total quantity of disease and neurodevelopmental factors at the molecular level. Single-cell sequencing subsequently identified cell-type specific alterations in neuronal programming factors as well as a developmental switch in neurotrophic growth factor expression, indicating that Scz neuropathology can be encoded on a cell-type-by-cell-type basis. Furthermore, single-cell sequencing also specifically replicated the depletion of BRN2 (POU3F2) and PTN in both Scz progenitors and neurons. Subsequently, in two mechanistic rescue experiments we identified that the transcription factor BRN2 and growth factor PTN operate as mechanistic substrates of neurogenesis and cellular survival, respectively, in Scz organoids. Collectively, our work suggests that multiple mechanisms of Scz exist in patient-derived organoids, and that these disparate mechanisms converge upon primordial brain developmental pathways such as neuronal differentiation, survival, and growth factor support, which may amalgamate to elevate intrinsic risk of Scz.

BDNF blood serum linkage with BDNF gene polymorphism (rs6265) in thyroid pathology patients in the West-Ukrainian population

Objective. Brain-derived neurotrophic factor (BDNF) is identified as an important growth factor involved in learning and memory. Patients with Hashimoto's thyroiditis can suffer from cognitive dysfunction, whereas BDNF is directly regulated by thyroid hormones. It seems reasonable to propose that changes in BDNF expression underlie some of the persistent neurological impairments associated with hypothyroidism. Methods. The study involved a total of 153 patients with various forms of thyroid pathology. BDNF levels in the sera of the patients and healthy individuals were quantified using enzyme-linked immunosorbent assay with highly sensitive Human BDNF ELISA Kit. Genotyping of the BDNF (rs6265) gene polymorphism using TaqMan probes and TaqMan Genotyping Master Mix (4371355) on CFX96™Real-Time PCR Detection System. Polymerase chain reaction (PCR) for TaqMan genotyping was carried out according to the kit instructions. Results. Distribution rs6265 variants in the patients depending on the different types of thyroid pathology showed no significant difference in the relative frequency of BDNF polymorphic variants. Presence of hypothyroidism, regardless of its cause (autoimmune or postoperative), there was a decrease in the serum BDNF levels in all genotypes carriers compared with the control group. The analysis of the correlation between BDNF levels and the levels of thyroid-stimulating hormone (TSH), thyroxine (T4), anti-thyroglobulin (anti-Tg), and anti-thyroid peroxidase (anti-TPO) antibodies showed a significant inverse relationship between BDNF and TSH levels (p<0.001), a direct correlation between BDNF and T4 levels in the blood (p<0.001), and a weak direct relationship between anti-Tg and BDNF levels (p=0.0157). Conclusion. The C allele presence is protective and associates with the lowest chances for reduced serum BDNF levels in thyroid pathology patients in the West-Ukrainian population. However, the T-allele increases the risk of low BDNF levels almost 10 times in observed subjects.

The proteomic architecture of schizophrenia iPSC-derived cerebral organoids reveals alterations in GWAS and neuronal development factors

Schizophrenia (Scz) is a brain disorder that has a typical onset in early adulthood but otherwise maintains unknown disease origins. Unfortunately, little progress has been made in understanding the molecular mechanisms underlying neurodevelopment of Scz due to ethical and technical limitations in accessing developing human brain tissue. To overcome this challenge, we have previously utilized patient-derived Induced Pluripotent Stem Cells (iPSCs) to generate self-developing, self-maturating, and self-organizing 3D brain-like tissue known as cerebral organoids. As a continuation of this prior work, here we provide an architectural map of the developing Scz organoid proteome. Utilizing iPSCs from n = 25 human donors (n = 8 healthy Ctrl donors, and n = 17 Scz patients), we generated 3D cerebral organoids, employed 16-plex isobaric sample-barcoding chemistry, and simultaneously subjected samples to comprehensive high-throughput liquid-chromatography/mass-spectrometry (LC/MS) quantitative proteomics. Of 3,705 proteins identified by high-throughput proteomic profiling, we identified that just ~2.62% of the organoid global proteomic landscape was differentially regulated in Scz organoids. In sum, just 43 proteins were up-regulated and 54 were down-regulated in Scz patient-derived organoids. Notably, a range of neuronal factors were depleted in Scz organoids (e.g., MAP2, TUBB3, SV2A, GAP43, CRABP1, NCAM1 etc.). Based on global enrichment analysis, alterations in key pathways that regulate nervous system development (e.g., axonogenesis, axon development, axon guidance, morphogenesis pathways regulating neuronal differentiation, as well as substantia nigra development) were perturbed in Scz patient-derived organoids. We also identified prominent alterations in two novel GWAS factors, Pleiotrophin (PTN) and Podocalyxin (PODXL), in Scz organoids. In sum, this work serves as both a report and a resource that researchers can leverage to compare, contrast, or orthogonally validate Scz factors and pathways identified in observational clinical studies and other model systems.

Genetic association between bone mineral density and the fracture of distal radius: A case-control study

Low bone mineral density (BMD) was significantly related to the fracture of distal radius. Serum brain-derived neurotrophic factor (BDNF) level was closely related to BMD in spine and osteoporotic fractures. In this study, we aimed to explore the association of BDNF polymorphisms (rs6265 and rs7124442) with BMD and the fracture of distal radius.This retrospective study included 152 patients with distal radius fractures and 148 healthy controls. BDNF polymorphisms were detected via TaqMan allelic discrimination assay. BMD was evaluated through X-ray. Difference in features between cases and controls were compared adopting Chi-square test or t test. The associations of BDNF polymorphisms with fracture risk of distal radius and BMD were assessed employing χ2 test and expressed by odd ratios (ORs) with 95% confidence intervals (95% CIs).BMD was significantly decreased in patients with the fracture of distal radius than in healthy controls. The polymorphism rs6265 significantly increased the risk of distal radius fracture (adjustment: GA: OR = 1.724, 95%CI = 1.003 -2.951, P = .049; GG: OR = 2.415, 95%CI = 1.0219 -3.674, P = .005). Moreover, rs6265 genotypes GA (OR = 4.326, 95%CI = 1.725 -11.896, P = .003) and GG (OR = 13.285, 95%CI = 3.659 -51.072, P = .001) significantly increased BMD reduction. However, BDNF polymorphism rs7124442 had no obvious correlation with BMD or fracture risk.BMD was associated with BDNF rs6265 polymorphism. BDNF polymorphism rs6265 could elevate the risk of osteoporosis and distal radius fracture.

ProBDNF Dependence of LTD and Fear Extinction Learning in the Amygdala of Adult Mice

Neurotrophins are secreted proteins that control survival, differentiation, and synaptic plasticity. While mature neurotrophins regulate these functions via tyrosine kinase signaling (Trk), uncleaved pro-neurotrophins bind preferentially to the p75 neurotrophin receptor (p75NTR) and often exert opposite effects to those of mature neurotrophins. In the amygdala, brain-derived neurotrophic factor (BDNF) enables long-term potentiation as well as fear and fear extinction learning. In the present study, we focused on the impact of mature BDNF and proBDNF signaling on long-term depression (LTD) in the lateral amygdala (LA). Hence, we conducted extracellular field potential recordings in an in vitro slice preparation and recorded LTD in cortical and thalamic afferents to the LA. LTD was unchanged by acute block of BDNF/TrkB signaling. In contrast, LTD was inhibited by blocking p75NTR signaling, by disinhibition of the proteolytic cleavage of proBDNF into mature BDNF, and by preincubation with a function-blocking anti-proBDNF antibody. Since LTD-like processes in the amygdala are supposed to be related to fear extinction learning, we locally inhibited p75NTR signaling in the amygdala during or after fear extinction training, resulting in impaired fear extinction memory. Overall, these results suggest that in the amygdala proBDNF/p75NTR signaling plays a pivotal role in LTD and fear extinction learning.

Association Analysis of Polymorphic Variants of the BDNF Gene in Athletes

As BDNF is one of the group of neurotrophins highly influencing the processes happening in the brain, such as the processes of learning and personality creation, we decided to look closer at its genetic variations in association with the personality of a group of athletes and their controls. The study group consisted of 305 volunteers: martial arts athletes (n = 153; mean age = 24.06) and healthy non-athletes as controls (n = 152; mean age = 22.23). Thirty-eight percent of the martial arts group achieved the championship level. Both the martial arts and control subjects were examined using the NEO Five-Factor Personality Inventory (NEO-FFI) and the State-Trait Anxiety Inventory (STAI) scales. The results of the NEO-FFI and STAI inventories were given as sten scores. The conversion of the raw score to the sten scale was performed according to Polish norms for adults. Genomic DNA was extracted from blood leukocytes and then genotyped using a PCR method for the following polymorphisms: BDNF rs10767664 and BDNF rs2030323. We observed statistical significance for both polymorphisms when comparing martial arts athletes with the control group in relation to the conscientiousness and extraversion scales. However, since few extant articles consider this association, our results still require further analysis, probably by considering a larger group.

A novel knockout mouse model of the noncoding antisense Brain-Derived Neurotrophic Factor (Bdnf) gene displays increased endogenous Bdnf protein and improved memory function following exercise

Brain-derived neurotrophic factor (Bdnf) expression is tightly controlled at the transcriptional and post-transcriptional levels. Previously, we showed that inhibition of noncoding Bdnf antisense (Bdnf-AS) RNA upregulates Bdnf protein. Here, we generated a Bdnf-antisense knockout (Bdnf-AS KO) mouse model by deleting 6 kilobases upstream of Bdnf-AS. After verifying suppression of Bdnf-AS, baseline behavioral tests indicated no significant difference in knockout and wild type mice, except for enhanced cognitive function in the knockout mice in the Y-maze. Following acute involuntary exercise, Bdnf-AS KO mice were re-assessed and a significant increase in Bdnf mRNA and protein were observed. Following long-term involuntary exercise, we observed a significant increase in nonspatial and spatial memory in novel object recognition and Barnes maze tests in young and aged Bdnf-AS KO mice. Our data provides evidence for the beneficial effects of endogenous Bdnf upregulation and the synergistic effect of Bdnf-AS knockout on exercise and memory retention.

Chronic methamphetamine interacts with BDNF Val66Met to remodel psychosis pathways in the mesocorticolimbic proteome

Methamphetamine (Meth) abuse has reached epidemic proportions in many countries and can induce psychotic episodes mimicking the clinical profile of schizophrenia. Brain-derived neurotrophic factor (BDNF) is implicated in both Meth effects and schizophrenia. We therefore studied the long-term effects of chronic Meth exposure in transgenic mice engineered to harbor the human BDNF^Val66Met polymorphism expressed via endogenous mouse promoters. These mice were chronically treated with an escalating Meth regime during late adolescence. At least 4 weeks later, all hBDNF^Val66Met Meth-treated mice exhibited sensitization confirming persistent behavioral effects of Meth. We used high-resolution quantitative mass spectrometry-based proteomics to biochemically map the long-term effects of Meth within the brain, resulting in the unbiased detection of 4808 proteins across the mesocorticolimbic circuitry. Meth differentially altered dopamine signaling markers (e.g., Dat, Comt, and Th) between hBDNF^Val/Val and hBDNF^Met/Met mice, implicating involvement of BDNF in Meth-induced reprogramming of the mesolimbic proteome. Targeted analysis of 336 schizophrenia-risk genes, as well as 82 growth factor cascade markers, similarly revealed that hBDNF^Val66Met genotype gated the recruitment of these factors by Meth in a region-specific manner. Cumulatively, these data represent the first comprehensive analysis of the long-term effects of chronic Meth exposure within the mesocorticolimbic circuitry. In addition, these data reveal that long-term Meth-induced brain changes are strongly dependent upon BDNF genetic variation, illustrating how drug-induced psychosis may be modulated at the molecular level by a single genetic locus.

Peptides Derived from Growth Factors to Treat Alzheimer's Disease

Alzheimer's disease (AD) is a devastating neurodegenerative disease characterized by progressive neuron losses in memory-related brain structures. The classical features of AD are a dysregulation of the cholinergic system, the accumulation of amyloid plaques, and neurofibrillary tangles. Unfortunately, current treatments are unable to cure or even delay the progression of the disease. Therefore, new therapeutic strategies have emerged, such as the exogenous administration of neurotrophic factors (e.g., NGF and BDNF) that are deficient or dysregulated in AD. However, their low capacity to cross the blood-brain barrier and their exorbitant cost currently limit their use. To overcome these limitations, short peptides mimicking the binding receptor sites of these growth factors have been developed. Such peptides can target selective signaling pathways involved in neuron survival, differentiation, and/or maintenance. This review focuses on growth factors and their derived peptides as potential treatment for AD. It describes (1) the physiological functions of growth factors in the brain, their neuronal signaling pathways, and alteration in AD; (2) the strategies to develop peptides derived from growth factor and their capacity to mimic the role of native proteins; and (3) new advancements and potential in using these molecules as therapeutic treatments for AD, as well as their limitations.

The Val66 and Met66 Alleles-Specific Expression of BDNF in Human Muscle and Their Metabolic Responsivity

Brain-derived neurotrophic factor (BDNF) plays an essential role in nervous system formation and functioning, including metabolism. Present only in humans, the “Val66Met” polymorphism of the BDNF gene (BDNF) is suggested to have a negative influence on the etiology of neurological diseases. However, this polymorphism has only been addressed, at the molecular level, in nonhuman models. Knowledge about Val66- and Met66-variant differences, to date, has been achieved at the protein level using either cell culture or animal models. Thus, the purpose of our study was to analyze the impact of the Val66Met polymorphism on BDNF expression in healthy humans and compare the allele-specific responses to metabolic stress. Muscle biopsies from 13 male recreational athletes (34 ± 9 years, 1.80 ± 0.08 m, 76.4 ± 10.5 kg) were obtained before and immediately following a VO₂max test. Allele-specific BDNF mRNA concentrations were quantified by droplet digital PCR (ddPCR) in heterozygous and homozygous subjects. The results indicated that BDNF expression levels were influenced by the genotype according to the presence of the polymorphism. BDNF expression from the Met66-coding alleles, in heterozygotes, was 1.3-fold lower than that from the Val66-coding alleles. Total BDNF mRNA levels in these heterozygotes remained below the whole sample’s mean. A partial dominance was detected for the Val66-coding variant on the Met66-coding’s. BDNF expression levels decreased by an average of 1.8-fold following the VO₂max test, independent of the individual’s genotype. The results of this study indicate that metabolic stress downregulates BDNF expression but not plasma BDNF concentrations. No correlation between expression level and plasma BDNF concentrations was found.

The Effects of P75NTR on Learning Memory Mediated by Hippocampal Apoptosis and Synaptic Plasticity

Neurological diseases bring great mental and physical torture to the patients, and have long-term and sustained negative effects on families and society. The attention to neurological diseases is increasing, and the improvement of the material level is accompanied by an increase in the demand for mental level. The p75 neurotrophin receptor (p75NTR) is a low-affinity neurotrophin receptor and involved in diverse and pleiotropic effects in the developmental and adult central nervous system (CNS). Since neurological diseases are usually accompanied by the regression of memory, the pathogenesis of p75NTR also activates and inhibits other signaling pathways, which has a serious impact on the learning and memory of patients. The results of studies shown that p75NTR is associated with LTP/LTD-induced synaptic enhancement and inhibition, suggest that p75NTR may be involved in the progression of synaptic plasticity. And its proapoptotic effect is associated with activation of proBDNF and inhibition of proNGF, and TrkA/p75NTR imbalance leads to pro-survival or proapoptotic phenomena. It can be inferred that p75NTR mediates apoptosis in the hippocampus and amygdale, which may affect learning and memory behavior. This article mainly discusses the relationship between p75NTR and learning memory and associated mechanisms, which may provide some new ideas for the treatment of neurological diseases.

Inhibiting BDNF/TrkB.T1 receptor improves resiniferatoxin-induced postherpetic neuralgia through decreasing ASIC3 signaling in dorsal root ganglia

BACKGROUND

Postherpetic neuralgia (PHN) is a devastating complication after varicella-zoster virus infection. Brain-derived neurotrophic factor (BDNF) has been shown to participate in the pathogenesis of PHN. A truncated isoform of the tropomyosin receptor kinase B (TrkB) receptor TrkB.T1, as a high-affinity receptor of BDNF, is upregulated in multiple nervous system injuries, and such upregulation is associated with pain. Acid-sensitive ion channel 3 (ASIC3) is involved in chronic neuropathic pain, but its relation with BDNF/TrkB.T1 in the peripheral nervous system (PNS) during PHN is unclear. This study aimed to investigate whether BDNF/TrkB.T1 contributes to PHN through regulating ASIC3 signaling in dorsal root ganglia (DRGs).

METHODS

Resiniferatoxin (RTX) was used to induce rat PHN models. Mechanical allodynia was assessed by measuring the paw withdrawal thresholds (PWTs). Thermal hyperalgesia was determined by detecting the paw withdrawal latencies (PWLs). We evaluated the effects of TrkB.T1-ASIC3 signaling inhibition on the behavior, neuronal excitability, and inflammatory response during RTX-induced PHN. ASIC3 short hairpin RNA (shRNA) transfection was used to investigate the effect of exogenous BDNF on inflammatory response in cultured PC-12 cells.

RESULTS

RTX injection induced mechanical allodynia and upregulated the protein expression of BDNF, TrkB.T1, ASIC3, TRAF6, nNOS, and c-Fos, as well as increased neuronal excitability in DRGs. Inhibition of ASIC3 reversed the abovementioned effects of RTX, except for BDNF and TrkB.T1 protein expression. In addition, inhibition of TrkB.T1 blocked RTX-induced mechanical allodynia, activation of ASIC3 signaling, and hyperexcitability of neurons. RTX-induced BDNF upregulation was found in both neurons and satellite glia cells in DRGs. Furthermore, exogenous BDNF activated ASIC3 signaling, increased NO level, and enhanced IL-6, IL-1β, and TNF-α levels in PC-12 cells, which was blocked by shRNA-ASIC3 transfection.

CONCLUSION

These findings demonstrate that inhibiting BDNF/TrkB.T1 reduced inflammation, decreased neuronal hyperexcitability, and improved mechanical allodynia through regulating the ASIC3 signaling pathway in DRGs, which may provide a novel therapeutic target for patients with PHN.

Long-term effects of young-adult methamphetamine on dorsal raphe serotonin systems in mice: Role of brain-derived neurotrophic factor

To assess the long-term effects of chronic adolescent methamphetamine (METH) treatment on the serotonin system in the brain, we used serotonin-1A receptor (5-HT_1A) and serotonin transporter (SERT) autoradiography, and quantitative tryptophan-hydroxylase 2 (TPH2) immunohistochemistry in the raphe nuclei of mice. Because of the modulatory role of brain-derived neurotrophic factor (BDNF) on the serotonin system and the effects of METH, we included both BDNF heterozygous (HET) mice and wildtype (WT) controls. Male and female mice of both genotypes were treated with an escalating METH dose regimen from the age of 6-9 weeks. At least two weeks later, acute locomotor hyperactivity induced by a 5 mg/kg D-amphetamine challenge was significantly enhanced in METH-pretreated mice, showing long-term sensitisation. METH pretreatment caused a small, but significant decrease of 5-HT_1A receptor binding in the dorsal raphe nucleus (DRN) of males independent of genotype, but there were no changes in the median raphe nucleus (MRN) or in SERT binding density. METH treatment reduced the number of TPH2 positive cells in ventral subregions of the rostral and medial DRN independent of genotype. METH treatment selectively reduced DRN cell counts in BDNF HET mice compared to wildtype mice in medial and caudal ventrolateral subregions previously associated with panic-like behaviour. The data increase our understanding of the long-term and selective effects of METH on brain serotonin systems. These findings could be relevant for some of the psychosis-like symptoms associated with long-term METH use.

BDNF affects the mediating effect of negative symptoms on the relationship between age of onset and cognition in patients with chronic schizophrenia

The age of onset of schizophrenia is related to variability in cognitive function and clinical characters, and negative symptoms and cognitive function share similar features that could be closely connected. Alterations in brain-derived neurotrophic factor (BDNF) expression and the Val66Met (rs6562) polymorphism are involved in the pathogenesis of the disease, but few studies have explored its influence on the associations of age of onset, cognitive function and clinical symptoms in schizophrenia. The clinical symptoms of a total of 573 patients with chronic schizophrenia were assessed by using the Positive and Negative Syndrome Scale (PANSS). Cognitive performance was assessed by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The serum BDNF level and Val66Met polymorphism were measured after the assessment. Our results showed the following: (1) patients with an earlier age of onset exhibited more negative symptoms and cognitive deficits, as well as lower levels of serum BDNF; (2) negative symptoms and cognitive function showed negative and positive correlations with age of onset, respectively, and worse cognitive function was associated with a high level of negative symptoms and a low level of serum BDNF; and (3) the moderated mediation analyses indicated that negative symptoms partially mediated the relationship between age of onset and cognitive deficits, which was moderated by serum BDNF. The mediating effect of negative symptoms exhibited a Met allele dose-dependent tendency. These results indicate that age of onset, cognitive function, and clinical symptoms of schizophrenia exhibit different relationships under different serum BDNF levels and BDNF Val66met polymorphisms.

Anti-Cognitive Decline by Yinxing-Mihuan-Oral-Liquid via Activating CREB/BDNF Signaling and Inhibiting Neuroinflammatory Process

BACKGROUND: Cognitive decline in the normal aging process is one of the most common and prominent problems. Delaying and alleviating cognitive impairment is an important strategy of anti-aging. This study is to aim at investigating the effects of Yinxing-Mihuan-Oral-Liquid(GMOL) on the CREB/BDNF signaling in the normal aging process.METHODS: SD rats were randomly divided into GMOL group and control group. The Morris water maze (MWM) was introduced for behavioral test. Immunohistochemistry and immunofluorescence were used for cAMP response element binding protein 1(CREB1), p-CREB(Ser133), brain-derived neurotrophic factor(BDNF), synaptophysin(SYP) and glial fibrillary acidic protein(GFAP). Western blot was conducted for investigating the levels of CREB1 and p-CREB(Ser133), BDNF, SYP, GFAP and interleukin 6(IL-6). RESULTS:  Our data showed that compared with the control group, GMOL group had higher expression of memory-related proteins, decreased inflammatory factors, and enhanced spatial learning and memory ability.CONCLUSION: The study results show that GMOL ameliorates cognitive impairment of the normal aged SD rats via enhancing the expression of memory biomarkers and inhibiting inflammatory process. The potential neuroprotective role of GMOL in the process of aging may be related to mitigating cognitive decline via activating CREB/BDNF signaling and inhibiting inflammatory process.

Immunoexpression of BDNF, TrkB, and p75NTR receptors in peripheral neural lesions of the head and neck

BACKGROUND

Brain-derived neurotrophic factor (BDNF) and neurotrophin receptors have been recognized as fundamental regulators of normal brain development, homeostasis, and plasticity. They have also been studied in the behavior of central nervous system tumors. Here, we studied the pattern of BDNF, TrkB and p75NTR immunoexpression in peripheral benign and malignant neural lesions in head and neck.

METHODS

This cross-sectional analytical study included 79 cases of head and neck neural lesions. Nineteen cases of traumatic neuromas (TN), 20 cases of granular cell tumors (GCT), 16 cases of neurofibromas (NF), 20 cases of schwannomas (SC), and 4 malignant peripheral nerve sheath tumor (MPNST) were submitted to immunohistochemistry with BDNF, TrkB, and p75NTR antibodies. A semi-quantitative analysis was performed.

RESULTS

The analysis of BDNF demonstrated a high percentage of positive cells in TN, GCT and SC with a decrease in cases of NF and MPNST. TrkB presented a lower significant immunoexpression in GCT in relation to the TN, NF, SC, and MPNST (P < .0001); and TN showed less percentage of positive cell compared to SC (P = .0017). Regarding p75NTR, the percentage of positive cell was significantly reduced in MPNST compared GCT (P = .009), NF (P = .0138) and SC (P = .0069). Also, a decrease in TN compared to GCT (P = .007) was observed.

CONCLUSIONS

Our results showed the immunoreactivity of BDNF, TrkB, and p75NTR in head and neck peripheral neural lesions. Reduction of BDNF and p75NTR in MPNST might suggest down-regulation during the acquisition of malignant phenotype.

Brain-Derived neurotrophic factor Val66Met induces female-specific changes in impulsive behaviour and alcohol self-administration in mice

Substance use disorders are a debilitating neuropsychiatric condition, however it remains unclear why some individuals are at greater risk of substance use disorders than others and what genetic factors determine such individual differences. Impulsivity appears a promising candidate endophenotype to bridge the gap between genetic risk and addiction. Brain-derived neurotrophic factor (BDNF), and in particular the BDNF^Val66Met polymorphism, has been suggested to be involved in both impulsivity and substance use disorders, however results so far have been inconsistent. To investigate the role of BDNF, and more specifically the BDNF^Val66Met polymorphism, in both impulsivity and operant alcohol self-administration using the same animal model. Separate cohorts of humanized Val66Met transgenic mice were assessed for either trait impulsivity in the 5-choice serial reaction time (5-CSRT) touchscreen task, or propensity towards obtaining ethanol in an operant paradigm. It was found that female hBDNF^Val/Val mice exhibited both greater impulsivity compared to hBDNF^Met/Met mice of the same sex as shown by a higher number of premature responses at one of three increased inter-trial intervals tested in the 5-CSRT task, and a greater propensity toward stable ethanol self-administration relative to male mice of the same genotype in the operant paradigm. By contrast, male mice showed no difference between genotypes in impulsivity or stable ethanol self-administration. The hBDNF^Met/Met genotype appears to sex-specifically alter aspects of both impulsive behaviour and addiction propensity. These results suggest that impulse behaviour may be a possible predictor of addiction risk.

Brain-derived Neurotropic Factor val66met is a Strong Predictor of Decision Making and Attention Performance on the CONVIRT Virtual Reality Cognitive Battery

The val66met polymorphism of the brain-derived neurotrophic factor gene has been associated with changes in components of executive functioning such as decision making; however, this relationship remains unclear. Val66met-related changes in attention and visual processing speed may explain potential changes in decision making. Furthermore, chronic stress disrupts executive functions and alters autonomic activity. Because the relationship between val66met and cognition has not been investigated in the context of chronic stress or stress-related autonomic changes, in this study 55 healthy university students completed self-report measures of chronic stress and mental health. Participants then completed a virtual reality cognitive test battery (CONVIRT) measuring decision making, attention, and visual processing reaction times. To measure autonomic activity, saliva alpha amylase and heart rate variability (HRV) were assessed at baseline and after CONVIRT testing. Saliva samples were used to identify val66met genotype. Regression analyses demonstrated that val66met was the strongest predictor of decision making and attention, but not visual processing, where valine/methionine (Val/met) participants had faster reaction times than Val/val participants. Val/met participants also had higher perceived chronic stress and heightened increases in sympathetic activity, but not parasympathetic activity. Neither stress nor autonomic activity moderated the effect of val66met on decision making or attention. This study is the first to investigate the role of val66met in decision making, attention, and visual processing while taking into account chronic stress and autonomic activity. This multifactorial approach revealed that carriers of the Val/met genotype may have better decision making and attention than Val/val carriers.

Brain-derived neurotrophic factor as a potential therapeutic tool in the treatment of nervous system disorders

Brain-derived neurotrophic factor (BDNF) plays an important role in the proper functioning of the nervous system. It regulates the growth and survival of nerve cells, and is crucial in processes related to the memory, learning and synaptic plasticity. Abnormalities related to the distribution and secretion of BDNF protein accompany many diseases of the nervous system, in the course of which a significant decrease in BDNF level in the brain is observed. Impairments of BDNF transport may occur, for example, in the event of a single nucleotide polymorphism in the Bdnf (Val66Met) coding gene or due to the dysfunctions of the proteins involved in intracellular transport, such as huntingtin (HTT), huntingtin-associated protein 1 (HAP1), carboxypeptidase E (CPE) or sortilin 1 (SORT1). One of the therapeutic goals in the treatment of diseases of the central nervous system may be the regulation of expression and secretion of BDNF protein by nerve cells. Potential therapeutic strategies are based on direct injection of the protein into the specific region of the brain, the use of viral vectors expressing the Bdnf gene, transplantation of BDNF-producing cells, the use of substances of natural origin that stimulate the cells of the central nervous system for BDNF production, or the use of molecules activating the main receptor for BDNF – tyrosine receptor kinase B (TrkB). In addition, an appropriate lifestyle that promotes physical activity helps to increase BDNF level in the body. This paper summarizes the current knowledge about the biological role of BDNF protein and proteins involved in intracellular transport of this neurotrophin. Moreover, it presents contemporary research trends to develop therapeutic methods, leading to an increase in the level of BDNF protein in the brain.

Neurobiology of BDNF in fear memory, sensitivity to stress, and stress-related disorders

Brain-derived neurotrophic factor (BDNF) is widely accepted for its involvement in resilience and antidepressant drug action, is a common genetic locus of risk for mental illnesses, and remains one of the most prominently studied molecules within psychiatry. Stress, which arguably remains the "lowest common denominator" risk factor for several mental illnesses, targets BDNF in disease-implicated brain regions and circuits. Altered stress-related responses have also been observed in animal models of BDNF deficiency in vivo, and BDNF is a common downstream intermediary for environmental factors that potentiate anxiety- and depressive-like behavior. However, BDNF's broad functionality has manifested a heterogeneous literature; likely reflecting that BDNF plays a hitherto under-recognized multifactorial role as both a regulator and target of stress hormone signaling within the brain. The role of BDNF in vulnerability to stress and stress-related disorders, such as posttraumatic stress disorder (PTSD), is a prominent example where inconsistent effects have emerged across numerous models, labs, and disciplines. In the current review we provide a contemporary update on the neurobiology of BDNF including new data from the behavioral neuroscience and neuropsychiatry literature on fear memory consolidation and extinction, stress, and PTSD. First we present an overview of recent advances in knowledge on the role of BDNF within the fear circuitry, as well as address mounting evidence whereby stress hormones interact with endogenous BDNF-TrkB signaling to alter brain homeostasis. Glucocorticoid signaling also acutely recruits BDNF to enhance the expression of fear memory. We then include observations that the functional common BDNF Val66Met polymorphism modulates stress susceptibility as well as stress-related and stress-inducible neuropsychiatric endophenotypes in both man and mouse. We conclude by proposing a BDNF stress-sensitivity hypothesis, which posits that disruption of endogenous BDNF activity by common factors (such as the BDNF Val66Met variant) potentiates sensitivity to stress and, by extension, vulnerability to stress-inducible illnesses. Thus, BDNF may induce plasticity to deleteriously promote the encoding of fear and trauma but, conversely, also enable adaptive plasticity during extinction learning to suppress PTSD-like fear responses. Ergo regulators of BDNF availability, such as the Val66Met polymorphism, may orchestrate sensitivity to stress, trauma, and risk of stress-induced disorders such as PTSD. Given an increasing interest in personalized psychiatry and clinically complex cases, this model provides a framework from which to experimentally disentangle the causal actions of BDNF in stress responses, which likely interact to potentiate, produce, and impair treatment of, stress-related psychiatric disorders.

Association between BDNF rs6265 polymorphisms and postoperative cognitive dysfunction in Chinese Han Population

INTRODUCTION

Brain-derived neurotrophic factor (BDNF) plays a critical role in the pathogenesis of postoperative cognitive dysfunction (POCD). In present study, we aimed to assess the possible association between POCD and BDNF rs6265 polymorphisms.

METHODS

124 patients aged 60 years or older scheduled for elective surgery under general anesthesia and 25 age- and gender-matched healthy volunteers were recruited. POCD was identified using a neuropsychological test battery administered preoperatively, 7 days, and 3 months after surgery. Genotyping of rs6265 was performed using polymerase chain reaction amplification and restriction fragment length polymorphism analysis.

RESULTS

99 patients and 25 healthy controls were finally enrolled in the analysis. 29(29.3%) and 18(18.2%) of 99 patients had POCD at 7 days and 3 months after surgery, respectively. The patients carrying a G allele at the rs6265 locus showed a lower risk for POCD than an A allele carriers on postoperative 7 days, but not 3 months after surgery (OR = 0.67; 95% CI: 0.47-0.96; p = .017; OR = 0.69; 95% CI: 0.42-1.13; p = .14, respectively). The risk of POCD at 7 days following surgery was significantly lower in additive model (OR = 0.41; 95% CI: 0.2-0.84; p = .015) and dominant model (OR = 0.35; 95% CI: 0.13-0.96; p = .042).

CONCLUSION

We tentatively demonstrate that BDNF rs6265 polymorphisms might be associated with occurrence of POCD at 7 days after surgery and the A > G mutant at the rs6265 locus be likely a protective factor for early POCD in Chinese Han population.

Association of circulating BDNF levels with BDNF rs6265 polymorphism in schizophrenia

Schizophrenia is a severe neuropsychiatric disorder affecting 1% of the world population. Disturbances in neuronal development and synaptic connections are important factors in the pathogenesis of schizophrenia. Brain derived neurotrophic factor (BDNF), a member of the neurotrophin family, plays a critical role in the development of neurons. Among several polymorphisms reported in BDNF, the rs6265 polymorphism is known to be associated with many neuropsychiatric diseases. This study was aimed to determine the effect of BDNF rs6265 functional polymorphism on serum BDNF concentration in patients with schizophrenia. In total, 50 schizophrenia patients and 50 controls were recruited after obtaining written informed consent. Serum BDNF levels were estimated using the ELISA method and BDNF rs6265 polymorphism was genotyped using T-ARMS PCR. Serum BDNF levels were decreased significantly in schizophrenia patients when compared to the healthy controls (p < 0.0001). Further, the rs6265 polymorphism was also not associated with the schizophrenia (p = 0.41). Intragroup analysis between different genotypes revealed no association between the serum BDNF levels and rs6265 polymorphism. Our results suggest that the functional polymorphism rs6265 is not associated with serum BDNF levels, which is in line with previous findings, which indicates that serum BDNF levels depend more on diagnostic effect than genetic effect. Replication studies on a larger study population are needed.

Neurotrophin signalling in amygdala-dependent cued fear learning

The amygdala is a central hub for fear learning assessed by Pavlovian fear conditioning. Indeed, the prevailing hypothesis that learning and memory are mediated by changes in synaptic strength was shown most convincingly at thalamic and cortical afferents to the lateral amygdala. The neurotrophin brain-derived neurotrophic factor (BDNF) is known to regulate synaptic plasticity and memory formation in many areas of the mammalian brain including the amygdala, where BDNF signalling via tropomyosin-related kinase B (TrkB) receptors is prominently involved in fear learning. This review updates the current understanding of BDNF/TrkB signalling in the amygdala related to fear learning and extinction. In addition, actions of proBDNF/p75NTR and NGF/TrkA as well as NT-3/TrkC signalling in the amygdala are introduced.

Effect of BDNF Val66Met on hippocampal subfields volumes and compensatory interaction with APOE-ε4 in middle-age cognitively unimpaired individuals from the ALFA study

Background

Current evidence supports the involvement of brain-derived neurotrophic factor (BDNF) Val66Met polymorphism, and the ε4 allele of APOE gene in hippocampal-dependent functions. Previous studies on the association of Val66Met with whole hippocampal volume included patients of a variety of disorders. However, it remains to be elucidated whether there is an impact of BDNF Val66Met polymorphism on the volumes of the hippocampal subfield volumes (HSv) in cognitively unimpaired (CU) individuals, and the interactive effect with the APOE-ε4 status.

Methods

BDNF Val66Met and APOE genotypes were determined in a sample of 430 CU late/middle-aged participants from the ALFA study (ALzheimer and FAmilies). Participants underwent a brain 3D-T1-weighted MRI scan, and volumes of the HSv were determined using Freesurfer (v6.0). The effects of the BDNF Val66Met genotype on the HSv were assessed using general linear models corrected by age, gender, education, number of APOE-ε4 alleles and total intracranial volume. We also investigated whether the association between APOE-ε4 allele and HSv were modified by BDNF Val66Met genotypes.

Results

BDNF Val66Met carriers showed larger bilateral volumes of the subiculum subfield. In addition, HSv reductions associated with APOE-ε4 allele were significantly moderated by BDNF Val66Met status. BDNF Met carriers who were also APOE-ε4 homozygous showed patterns of higher HSv than BDNF Val carriers.

Conclusion

To our knowledge, the present study is the first to show that carrying the BDNF Val66Met polymorphisms partially compensates the decreased on HSv associated with APOE-ε4 in middle-age cognitively unimpaired individuals.

Electronic supplementary material

The online version of this article (10.1007/s00429-020-02125-3) contains supplementary material, which is available to authorized users.

7,8-Dihydroxyflavone Enhances Cue-Conditioned Alcohol Reinstatement in Rats

Alcohol use disorder (AUD) is a detrimental disease that develops through chronic ethanol exposure. Reduced brain-derived neurotrophic factor (BDNF) expression has been associated with AUD and alcohol addiction, however the effects of activation of BDNF signalling in the brain on voluntary alcohol intake reinstatement and relapse are unknown. We therefore trained male and female Sprague Dawley rats in operant chambers to self-administer a 10% ethanol solution. Following baseline acquisition and progressive ratio (PR) analysis, rats were split into drug and vehicle groups during alcohol lever extinction. The animals received two weeks of daily IP injection of either the BDNF receptor, TrkB, agonist, 7,8-dihydroxyflavone (7,8-DHF), or vehicle. During acquisition of alcohol self-administration, males had significantly higher absolute numbers of alcohol-paired lever presses and a higher PR breakpoint. However, after adjusting for body weight, the amount of ethanol was not different between the sexes and the PR breakpoint was higher in females than males. Following extinction, alcohol-primed reinstatement in male rats was not altered by pretreatment with 7,8-DHF when adjusted for body weight. In contrast, in female rats, the weight-adjusted potential amount of ethanol, but not absolute numbers of active lever presses, was significantly enhanced by 7,8-DHF treatment during reinstatement. Analysis of spontaneous locomotor activity in automated photocell cages suggested that the effect of 7,8-DHF was not associated with hyperactivity. These results suggest that stimulation of the TrkB receptor may contribute to reward craving and relapse in AUD, particularly in females.

The BDNF Val66Met Polymorphism Modulates Resilience of Neurological Functioning to Brain Ageing and Dementia: A Narrative Review

Brain-derived neurotropic factor (BDNF) is an abundant and multi-function neurotrophin in the brain. It is released following neuronal activity and is believed to be particularly important in strengthening neural networks. A common variation in the BDNF gene, a valine to methionine substitution at codon 66 (Val66Met), has been linked to differential expression of BDNF associated with experience-dependent plasticity. The Met allele has been associated with reduced production of BDNF following neuronal stimulation, which suggests a potential role of this variation with respect to how the nervous system may respond to challenges, such as brain ageing and related neurodegenerative conditions (e.g., dementia and Alzheimer’s disease). The current review examines the potential of the BDNF Val66Met variation to modulate an individual’s susceptibility and trajectory through cognitive changes associated with ageing and dementia. On balance, research to date indicates that the BDNF Met allele at this codon is potentially associated with a detrimental influence on the level of cognitive functioning in older adults and may also impart increased risk of progression to dementia. Furthermore, recent studies also show that this genetic variation may modulate an individual’s response to interventions targeted at building cognitive resilience to conditions that cause dementia.

Interrelation Between Increased BDNF Gene Methylation and High Sociotropy, a Personality Vulnerability Factor in Cognitive Model of Depression

PURPOSE

It is suggested that increased methylation of the brain-derived neurotrophic factor (BDNF) gene is involved in the pathogenesis of depression, while sociotropy and autonomy are proposed as personality vulnerability factors in cognitive model of depression. We examined the interrelation between BDNF gene methylation and sociotropy or autonomy, with taking into account the previously reported deleterious effect of parental overprotection on sociotropy.

MATERIALS AND METHODS

The participants consisted of 90 healthy Japanese volunteers. Methylation levels of the BDNF gene in peripheral blood were quantified by bisulfite pyrosequencing. Sociotropy and autonomy were assessed by the Sociotropy-Autonomy Scale, and perceived parental protection was evaluated by the Parental Bonding Instrument.

RESULTS

In Pearson's correlation analysis, there was a positive correlation between methylation levels of the BDNF gene and sociotropy scores (p<0.05) but not autonomy scores, and a positive correlation between maternal protection scores and sociotropy scores (p<0.05). In structural equation modeling, two models were proposed; the first one is that hypermethylation of the BDNF gene and maternal overprotection independently contribute to high sociotropy, and the second one is that maternal overprotection contributes to high sociotropy which then leads to hypermethylation of the BDNF gene.

CONCLUSION

The present study suggests an interrelation between increased BDNF gene methylation and high sociotropy.

The Role of Altered BDNF/TrkB Signaling in Amyotrophic Lateral Sclerosis

Brain derived neurotrophic factor (BDNF) is well recognized for its neuroprotective functions, via activation of its high affinity receptor, tropomysin related kinase B (TrkB). In addition, BDNF/TrkB neuroprotective functions can also be elicited indirectly via activation of adenosine 2A receptors (A_2aRs), which in turn transactivates TrkB. Evidence suggests that alterations in BDNF/TrkB, including TrkB transactivation by A_2aRs, can occur in several neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). Although enhancing BDNF has been a major goal for protection of dying motor neurons (MNs), this has not been successful. Indeed, there is emerging in vitro and in vivo evidence suggesting that an upregulation of BDNF/TrkB can cause detrimental effects on MNs, making them more vulnerable to pathophysiological insults. For example, in ALS, early synaptic hyper-excitability of MNs is thought to enhance BDNF-mediated signaling, thereby causing glutamate excitotoxicity, and ultimately MN death. Moreover, direct inhibition of TrkB and A_2aRs has been shown to protect MNs from these pathophysiological insults, suggesting that modulation of BDNF/TrkB and/or A_2aRs receptors may be important in early disease pathogenesis in ALS. This review highlights the relevance of pathophysiological actions of BDNF/TrkB under certain circumstances, so that manipulation of BDNF/TrkB and A_2aRs may give rise to alternate neuroprotective therapeutic strategies in the treatment of neural diseases such as ALS.