BDNF function in adult synaptic plasticity: the synaptic consolidation hypothesis

Effects of maternal drinking patterns and epigallocatechin-3-gallate treatment on behavioural and molecular outcomes in a mouse model of fetal alcohol spectrum disorders

Prenatal alcohol exposure (PAE) impairs fetal development leading to fetal alcohol spectrum disorders (FASD). Antioxidants like epigallocatechin-3-gallate (EGCG) may mitigate alcohol-induced oxidative stress, a major contributor to FASD. This study assessed the effects of PAE on cognition and behaviour under two drinking patterns and the role of postnatal EGCG therapy in a FASD-like mouse model. C57BL/6J mice were divided into five groups: control, moderate drinking (Mod), binge drinking (Bin), Mod+EGCG, and Bin+EGCG. Cognitive and behavioural performance were assessed using Rotarod test, T-Maze, and Morris Water Maze (MWM). Western blot analyses evaluated brain and cerebellum biomarkers related to neuronal plasticity, maturation, differentiation, transport, and proliferation. PAE impaired motor coordination, significantly reducing rotarod walking time in both drinking patterns. Spatial learning and memory were also disrupted, decreasing T-maze success rate. It also decreased time in the platform area and distance travelled in MWM. Both drinking patterns affected neuronal plasticity (BDNF, DYRK1A) and maturation (NeuN), astrocyte differentiation (GFAP, s100β), neuronal transport (MBP) and proliferation (GDNF, Wnt-3) via oxidative stress (Nrf2). Our results show how EGCG treatment significantly improved behavioural tests results and restored most brain and cerebellum biomarkers, reaching levels similar to control. These findings highlight the impact of PAE on cognition and behaviour and how EGCG may counteract its effects by reducing oxidative stress and enhancing brain plasticity. Our findings open the door to future studies on the mechanism of action of this antioxidant in order to use it as a therapeutic tool in this vulnerable population.

Mesenchymal Stem Cells Expressing Baculovirus-Engineered Brain-Derived Neurotrophic Factor Improve Peripheral Nerve Regeneration in a Rat Model

BACKGROUND

Peripheral nerve injuries are a major clinical challenge because of their complex nature and limited regenerative capacity. This study aimed to improve peripheral nerve regeneration using Wharton's jelly mesenchymal stem cells (WJ-MSCs) engineered to express brain-derived neurotrophic factor (BDNF) via a baculovirus (BV) vector. The cells were evaluated for efficacy when seeded into acellular nerve grafts (ANGs) in a rat sciatic nerve defect model.

METHODS

WJ-MSCs were transfected with recombinant BV to upregulate BDNF expression. Conditioned medium (CM) from these cells was utilized to treat Schwann cells (SCs), and the impact on myelination-related markers, including KROX20, myelin basic protein (MBP), glial fibrillary acidic protein (GFAP), and S100 calcium-binding protein β (S100β), and the activation of the mammalian target of rapamycin (mTOR)/ protein kinase B (AKT)/p38 signaling pathways were evaluated. In vivo, BDNF-expressing WJ-MSCs were seeded into ANGs and implanted into a rat sciatic nerve defect model. Functional recovery was evaluated via video gait analysis, isometric tetanic force measurement, muscle weight evaluation, ankle contracture angle measurement, and histological analysis using toluidine blue staining.

RESULTS

BDNF expression was significantly upregulated in WJ-MSCs post-transfection. BDNF-MSC CM substantially promoted the expression of myelination markers in SCs and activated the mTOR/AKT/p38 signaling pathway. In the rat model, seeding of ANGs with BDNF-expressing WJ-MSCs resulted in improved functional outcomes, including enhanced toe-off angles, increased isometric tetanic force, greater muscle weight recovery, and a higher total number of myelinated axons compared with controls.

CONCLUSION

WJ-MSCs engineered to express BDNF significantly enhanced peripheral nerve regeneration when utilized in conjunction with ANGs. These findings indicate BDNF-expressing WJ-MSCs are a promising therapeutic approach for treating peripheral nerve injuries.

Brain-Derived Neurotrophic Factor (BDNF) is Associated with Self-Reported Cognitive Function in Adults with HIV

Background: People with HIV (PWH) are at risk of developing HIV-associated neurocognitive disorder (HAND) despite receiving combination antiretroviral therapy. Brain-derived neurotrophic factor (BDNF) has been implicated in cognitive function and neuroplasticity, but its role in HIV-related neuroinflammation remains understudied. Methods: This study analyzed data from the CHAMPS study, assessing BDNF serum levels and cognitive function in 140 adults with HIV at baseline. Cognitive function was evaluated using the PROMIS Applied Cognition-Abilities 8-item questionnaire. BDNF levels (pg/ml) were measured using high sensitivity Enzyme-Linked Immunoassay (ELISA) kits. Linear regression analyses were conducted to explore the associations between BDNF levels, cognitive function, and AIDS diagnosis, adjusting for demographic variables. Results: A significant positive association was found between BDNF levels and cognitive function scores in PWH (p = .03). Additionally, PWH with a history of AIDS diagnosis showed significantly lower BDNF levels (p = .02). Other demographic factors did not significantly impact cognitive function or BDNF levels in this cohort. Conclusions: Our results highlight the potential of BDNF as a biomarker for cognitive decline in PWH and suggest its relevance in understanding HAND pathophysiology. Further research is warranted to explore the multifaceted interactions influencing cognitive outcomes in this population and to develop targeted interventions for improving cognitive health in PWH.

Enhanced BDNF and ROS in Mucosa of Lower Motor Neuron Lesioned Dog Bladder Following Somatic Motor Nerve Transfer

Neurotrophic factors and reactive oxygen species (ROS) modulate neuronal plasticity. In a model of a lower motor neuron lesioned bladder, somatic nerve transfer was used as a reinnervation strategy. Levels of neurotrophins, ROS, and TNF-α in bladder mucosa and muscle layers collected from three groups of adult female dogs: (1) Decentralized, via bilateral transection of coccygeal and sacral spinal roots, lumbar 7 dorsal roots, and hypogastric nerves, then 6-21 mo recovery; (2) reinnervated (ObNT-Reinn), after similar decentralization for 12 mo, then bilateral obturator-to-vesical nerve transfer and 8-12 mo recovery; and (3) Controls. In mucosa, BDNF and ROS levels were highest in ObNT-Reinn bladders, GDNF and TNF-α levels were restored to Control levels in ObNT-Reinn bladders (lowest in Decentralized). NT-3 and ARTN were lower in ObNT-Reinn and Decentralized bladders versus Controls. In muscle, ROS was lower in ObNT-Reinn muscle versus Controls. BDNF mucosa levels correlated with bladder axonal density and detrusor layer thickness; and GDNF mucosal correlated with bladder contraction after vesical or transferred obturator nerve electrical stimulation, as did BDNF and GDNF muscle levels. The increased BDNF and GDNF in bladders that underwent somatic nerve transfer with subsequent recovery suggest that BDNF and GDNF may help promote the reestablishment of bladder innervation.

Lateral hypothalamic area high-frequency deep brain stimulation rescues memory decline in aged rat: behavioral, molecular, and electrophysiological study

To examine the effect of DBS of the lateral hypothalamic area (LHA) on age-related memory changes, neuronal firing from CA1, oxidative stress, and the expression of Hsp70, BDNF, and synaptophysin. 72 male rats were randomly allocated into 6 equal groups: a) normal young group (8 W), b) sham young group, c) DBS young group, d) normal old group (24 months), e) sham old group and f) DBS old group. Memory tests (passive avoidance and Y maze), oxidative stress markers (MDA, catalase, and GSH) and expression of Nrf2, HO-1, Hsp70, BDNF, and synaptophysin were measured by the end of the experiment. Also, in vivo recording of the neuronal firing of the CA1 region in the hippocampus was done. Old rats show significant decline in memories, antioxidant genes (Nrf2 and HO-1), antioxidants (GSH and catalase), Hsp70, BDNF, and synaptophysin with significant increase in MDA in hippocampus (p < 0.05) and DBS for LHA caused a significant improvement in memories in old rats, with significant rise in fast gamma and theta waves in CA1 region in old rats (p < 0.05). This was associated with a significant increase in antioxidants (GSH and CAT), antioxidant genes (Nrf2, HO-1), Hsp70, BDNF, and synaptophysin with significant reduction in MDA in hippocampus (p < 0.05). DBS for LHA ameliorates the age-induced memory decline. This might be due to increase in fast gamma in CA1, attenuation of oxidative stress, upregulation of Nrf2, HO-1, Hsp70, BDNF, and synaptophysin in the hippocampus.

Localized release of muscle-generated BDNF regulates the initial formation of postsynaptic apparatus at neuromuscular synapses

Growing evidence indicates that brain-derived neurotrophic factor (BDNF) is produced in contracting skeletal muscles and is secreted as a myokine that plays an important role in muscle metabolism. However, the involvement of muscle-generated BDNF and the regulation of its vesicular trafficking, localization, proteolytic processing, and spatially restricted release during the development of vertebrate neuromuscular junctions (NMJs) remain largely unknown. In this study, we first reported that BDNF is spatially associated with the actin-rich core domain of podosome-like structures (PLSs) at topologically complex acetylcholine receptor (AChR) clusters in cultured Xenopus muscle cells. The release of spatially localized BDNF is tightly controlled by activity-regulated mechanisms in a calcium-dependent manner. Live-cell time-lapse imaging further showed that BDNF-containing vesicles are transported to and captured at PLSs in both aneural and synaptic AChR clusters for spatially restricted release. Functionally, BDNF knockdown or furin-mediated endoproteolytic activity inhibition significantly suppresses aneural AChR cluster formation, which in turn affects synaptic AChR clustering induced by nerve innervation or agrin-coated beads. Lastly, skeletal muscle-specific BDNF knockout (MBKO) mice exhibit structural defects in the formation of aneural AChR clusters and their subsequent recruitment to nerve-induced synaptic AChR clusters during the initial stages of NMJ development in vivo. Together, this study demonstrated the regulatory roles of PLSs in the intracellular trafficking, spatial localization, and activity-dependent release of BDNF in muscle cells and revealed the involvement of muscle-generated BDNF and its proteolytic conversion in regulating the initial formation of aneural and synaptic AChR clusters during early NMJ development in vitro and in vivo.

Candidate Key Proteins in Tinnitus-A Bioinformatic Study of Synaptic Transmission in the Inferior Colliculus

Proteins involved in synaptic transmission in normal hearing, acoustic stimulation, and tinnitus were identified using protein-protein interaction (PPI) networks. The gene list for tinnitus was compiled from the GeneCards database using the keywords "synaptic transmission" AND "inferior colliculus" AND "tinnitus" (Tin). For comparison, two gene lists were built using the keywords "auditory perception" (AP) and "acoustic stimulation" (AS). The STRING and the Cytoscape data analyzer were used to identify the top two high-degree proteins (HDPs) and the corresponding high-score interaction proteins (HSIP). The top1 key proteins of the AP and AS processes are BDNF and the receptor NTRK2; the top2 key proteins in the AP process are PVALB, together with GAD1, CALB1, and CALB2, which are important for the balance of excitation and inhibition. In the AS process, the top2 key proteins are FOS, CREB1, EGR1, and MAPK1, reflecting an activated state. The top1 key proteins of the Tin process are BDNF, NTRK3, and NTF3; these proteins are associated with the proliferation and differentiation of neurons and indicate the remodeling of synaptic transmission in IC. The top2 key proteins are GFAP and S100B, indicating a role for astrocytes in the modulation of synaptic transmission.

LM22A-4-loaded smart mesoporous balls enhance neuroprotection and functional recovery after ischemic stroke

Stroke is globally recognized as the second leading cause of death, significantly impairing both motor and cognitive functions. Enhancing regeneration after stroke is crucial for restoring these functions and necessitates strategies to promote neuroregeneration to achieve better post-stroke outcomes. Brain-derived neurotrophic factor (BDNF) plays a key role in neuroregeneration by influencing motor ability, learning, memory, and rehabilitation after stroke. However, challenges such as the substantial protein size, short half-life of BDNF, and blood-brain barrier hinder its efficient delivery to the brain. In this study, LM22A-4, a BDNF mimetic, was utilized and delivered through a Smart Mesoporous Ball (SMB-3) system to target the ischemic injured brain and explore its potential therapeutic effects in a mouse ischemic stroke model. Treatment with LM22A-4-loaded SMB-3 (LM22A-4-SMB-3) markedly restored neurological, motor, and cognitive deficits following ischemic stroke compared to LM22A-4 alone. Additionally, administration of LM22A-4-SMB-3 reduced apoptotic cell death and glial activation, as evidenced by the TUNEL assay results, and decreased GFAP and Iba-1 expression levels. Furthermore, the phosphorylation of TrkB and Akt, but not that of Erk, was considerably increased in the LM22A-4-SMB-3-treated group. Treatment also enhanced the number of BrdU+/NeuN+ cells, with a marked reduction in post-stroke brain atrophy. These findings suggest that LM22A-4-SMB-3 can attenuate ischemic damage and recover neurological, motor, and cognitive functions by increasing p-TrkB and p-Akt levels and promoting neurogenesis. Therefore, SMB-3-mediated delivery of LM22A-4 presents a potentially applicable delivery system, and LM22A-4-SMB-3 use could be considered a novel therapeutic strategy to improve post-stroke outcomes.

Exploring the association between BDNF related signaling pathways and depression: A literature review

Depression is a debilitating mental disease that inflicts significant harm upon individuals and society, yet effective treatment options remain elusive. At present, the pathogenesis of multiple depression is not fully clear, but its occurrence can be related to biological or environmental pathways, among which Brain-derived neurotrophic factor (BDNF) can unequivocally act on two downstream receptors, tyrosine kinase receptor (TrkB) and the p75 neurotrophin receptor (p75NTR), then affect the related signal pathways, affecting the occurrence and development of depression. Accumulating studies have revealed that BDNF-related pathways are critical in the pathophysiology of depression, and their interaction can further influence the efficacy of depression treatment. In this review, we mainly summarized the signaling pathways associated with BDNF and classified them according to different receptors and related molecules, providing promising insights and future directions in the treatment of depression.

Exploring β-caryophyllene: a non-psychotropic cannabinoid's potential in mitigating cognitive impairment induced by sleep deprivation

Sleep deprivation or sleep loss, a prevalent issue in modern society, is linked to cognitive impairment, leading to heightened risks of errors and accidents. Chronic sleep deprivation affects various cognitive functions, including memory, attention, and decision-making, and is associated with an increased risk of neurodegenerative diseases, cardiovascular issues, and metabolic disorders. This review examines the potential of β-caryophyllene, a dietary non-psychotropic cannabinoid, and FDA-approved flavoring agent, as a therapeutic solution for sleep loss-induced cognitive impairment. It highlights β-caryophyllene's ability to mitigate key contributors to sleep loss-induced cognitive impairment, such as inflammation, oxidative stress, neuronal death, and reduced neuroplasticity, by modulating various signaling pathways, including TLR4/NF-κB/NLRP3, MAPK, Nrf2/HO-1, PI3K/Akt, and cAMP/PKA/CREB. As a naturally occurring, non-psychotropic compound with low toxicity, β-caryophyllene emerges as a promising candidate for further investigation. The review underscores the therapeutic potential of β-caryophyllene for sleep loss-induced cognitive impairment and provides mechanistic insights into its action on crucial pathways, suggesting that β-caryophyllene could be a valuable addition to strategies aimed at combating cognitive impairment and other health issues due to sleep loss.

Effects of electroconvulsive therapy on serum brain derived neurotrophic factor, serum interleukin-6, and serum cortisol levels in patients with treatment refractory schizophrenia

Background

Schizophrenia (SCZ) is a severe psychiatric disorder characterized by cognitive dysfunction and persistent psychotic symptoms. Treatment refractory schizophrenia (TRS), resistant to conventional antipsychotics, presents significant challenges. Electroconvulsive therapy (ECT) is effective for TRS, but its biological mechanisms remain unclear. Biomarkers such as brain-derived neurotrophic factor (BDNF), interleukin-6 (IL-6), and cortisol, linked to neuroplasticity, immune modulation, and stress regulation, may help elucidate ECT's therapeutic effects.

Aim

This study evaluated the impact of ECT on serum levels of BDNF, IL-6, and cortisol in TRS patients and explored the relationship between these biomarkers and symptom improvement.

Materials and Methods

A prospective study was conducted at a tertiary care hospital from 2018 to 2020. Thirty-five TRS patients (aged 18-60 years) underwent symptom severity assessments using the positive and negative syndrome scale (PANSS) pre- and post-ECT. Serum levels of BDNF, IL-6, and cortisol were measured using enzyme-linked immunosorbent assays (ELISA). ECT was administered bilaterally in 4-7 sessions per patient. Paired t-tests and Spearman's correlation were used for statistical analysis.

Results

ECT significantly reduced positive (P < 0.001), general (P < 0.001), and total PANSS scores (P < 0.001), with modest reductions in negative symptoms (P < 0.001). Serum IL-6 levels decreased significantly post-ECT (P = 0.018), while changes in BDNF (P = 0.198) and cortisol (P = 0.403) were not statistically significant. Increased BDNF levels positively correlated with reduced positive symptoms (P = 0.041), while decreased IL-6 levels correlated with symptom improvement (P = 0.045).

Conclusion

ECT reduces symptom severity in TRS, with significant modulation of IL-6 and potential involvement of BDNF in positive symptom improvement. These findings highlight immune and neuroplastic pathways as mechanisms of ECT efficacy and suggest biomarkers for treatment response.

Clinical, molecular, physiologic, and therapeutic feature of patients with CHRNA4 and CHRNB2 deficiency: A systematic review

The α4β2 nAChRs are crucial ion channels that control neurotransmitter release and play a role in various physiologic and pathologic processes. CHRNA4 encodes the α4-nAChRs, while CHRNB2 encodes the β2-nAChRs. Recent studies have found different variants of α4β2-nAChRs in individuals with conditions such as AD, ADHD, ALS, PD, and brain abnormalities. We conducted a scoping review following a six-stage methodology structure and adhering to PRISMA guidelines. We systematically reviewed articles using relevant keywords up to October 2, 2023. In this summary, we cover the clinical symptoms reported, the genes and protein structure of CHRNA4 and CHRNB2, mutations in these genes, inheritance patterns, the functional impact of mutations and polymorphisms in CHRNA4 and CHRNB2, and the epidemiology of these diseases. Recent research indicates that nAChRs may play a significant role in neurodegenerative disorders, possibly impacting neuronal function through yet undiscovered regulatory pathways. Studying how nAChRs interact with disease-related aggregates in neurodegenerative conditions may lead to new treatment options for these disorders.

Molecular biomarkers of dysphagia targeted exercise induced neuroplasticity: A review of mechanistic processes and preliminary data on detraining effects

While molecular adaptations accompanying neuroplasticity during physical exercises are well-established, little is known about adaptations during dysphagia-targeted exercises. This research article has two primary purposes. First, we aim to review the existing literature on the intersection between resistance (strength) training, molecular markers of neuroplasticity, and dysphagia rehabilitation. Specifically, we discuss the molecular mechanisms of two potential molecular markers: brain-derived neurotrophic factor (BDNF) and insulin-like growth factor-1 (IGF-1) in exercise-induced neuroplasticity. Second, we present preliminary data on the effects of two weeks of detraining on circulating serum BDNF, IGF-1 levels, and expiratory muscle strength. This subset is a part of our more extensive studies related to dysphagia-targeted resistance exercise and neuroplasticity. Five young adult males underwent four weeks of expiratory muscle strength training, followed by two weeks of detraining. We measured expiratory strength, circulating levels of BDNF, and IGF-1 at post-training and detraining conditions. Our results show that expiratory muscle strength, serum BDNF, and IGF-1 levels decreased after detraining; however, this effect was statistically significant only for serum BDNF levels. Oropharyngeal and upper airway musculature involved in swallowing undergoes similar adaptation patterns to skeletal muscles during physical exercise. To fully comprehend the mechanisms underlying the potential neuroplastic benefits of targeted exercise on swallowing functions, mechanistic studies (models) investigating neuroplasticity induced by exercises addressing dysphagia are critical. Such models would ensure that interventions effectively and efficiently achieve neuroplastic benefits and improve patient outcomes, ultimately advancing our understanding of dysphagia-targeted exercise-induced neuroplasticity.

Nelumbo nucifera Petals Ameliorate Depressive-like Symptom and Cognitive Deficit in Unpredictable Chronic Mild Stress Mouse Model

Background Chronic stress exposure has been widely recognized as a significant contributor to numerous central nervous system (CNS) disorders, leading to debilitating behavioral changes such as anxiety, depression, and cognitive impairments. The prolonged activation of the hypothalamic-pituitary-adrenal (HPA) axis during chronic stress disrupts the neuroendocrine balance and has detrimental effects on neuronal function and survival. Nelumbo nucifera (N. nucifera) Gaertn., commonly known as the lotus flower, is a traditional medicinal plant consumed for its purported benefits on mental and physical well-being. Despite its traditional use, limited scientific evidence supports these claims. Methods The present study explores the effects of N. nucifera, commonly known as the lotus flower, on cognitive performance and stress resilience in a mouse model subjected to unpredictable chronic mild stress (UCMS). Results Daily treatment significantly improved cognitive performance, alleviated depressive-like behaviors, and normalized hypothalamic-pituitary-adrenal (HPA) axis activity, as indicated by a 60.97% reduction in serum corticosterone. At the molecular level, N. nucifera petals also downregulated serum- and glucocorticoid-inducible kinase 1 (SGK1) mRNA expression while upregulating brain-derived neurotrophic factor (BDNF) mRNA expression and cyclic-adenosine monophosphate (cAMP) responsive element-binding protein (CREB) mRNA expression in the hippocampus and frontal cortex. These normalizations are critical, as chronic stress dysregulates HPA axis function, exacerbating behavioral changes. Furthermore, a phytochemical analysis resulted in the isolation of five major compounds, kaempferol (1), trifolin (2), kaempferol-3-neohesperidoside (3), icariside D2 (4), and β-sitosterol (5), each demonstrating significant monoamine oxidase (MAO) inhibitory activity. Conclusions These compelling findings suggest that N. nucifera petals not only alleviate stress-induced mood and cognitive deficits but also offer a promising avenue for modulating the HPA axis and promoting neuroprotection via essential neurotrophic factors and enzymatic pathways. We advocate for its potential as a complementary and alternative medicine for effective stress management. Future investigations should further explore its mechanisms of action and evaluate its clinical applicability in stress-related disorders.

Effects of Acacia catechu and Scutellaria baicalensis extract on cognitive function in a healthy adult population: a double-blind, randomized, placebo-controlled trial

Flavonoids, known for their neuroprotective properties, are abundant in Acacia catechu and Scutellaria baicalensis. Yet, human studies on their combined effects are limited.

OBJECTIVE

This study evaluated the cognitive effects of combined Acacia catechu and Scutellaria baicalensis supplementation in healthy adults.

METHODS

In a randomized, double-blind, placebo-controlled trial, 26 males and 59 females (N = 85; 43 ± 8 yrs) consumed the test product (TP) containing 240 mg stem extract of Scutellaria baicalensis and 51 mg heartwood extract of Acacia catechu (UP326, Unigen, Tacoma, WA USA) or placebo (PLA) for four weeks. Cognitive function and biomarkers were assessed throughout the study.

RESULTS

Significant time effects (p < 0.001) were observed across cognitive function assessments, with no differences between groups. Energy and fatigue reports showed a significant time effect (p = 0.023), while no significant differences emerged in general health and well-being scores. Cortisol levels increased significantly over time across conditions (p = 0.005), but no significant changes were observed in change scores or individual visits. Interim (p = 0.023) and final (p = 0.004) absolute basophil levels differed significantly between groups, with no intergroup changes. No significant differences in BDNF, CRP, or health and safety biomarkers were detected between supplemental conditions or over time.

DISCUSSION

Four-week daily TP supplementation significantly enhanced cognitive function without difference from placebo. However, no adverse events or significant blood marker changes were noted, suggesting TP supplementation is generally well-tolerated. Further research is warranted to explore the preventive and attenuating cognitive effects of this supplementation.Trial registration: ISRCTN.org identifier: ISRCTN16548309.

Boosting Psychotherapy With Noninvasive Brain Stimulation: The Whys and Wherefores of Modulating Neural Plasticity to Promote Therapeutic Change

The phenomenon of neural plasticity pertains to the intrinsic capacity of neurons to undergo structural and functional reconfiguration through learning and experiential interaction with the environment. These changes could manifest themselves not only as a consequence of various life experiences but also following therapeutic interventions, including the application of noninvasive brain stimulation (NIBS) and psychotherapy. As standalone therapies, both NIBS and psychotherapy have demonstrated their efficacy in the amelioration of psychiatric disorders' symptoms, with a certain variability in terms of effect sizes and duration. Consequently, scholars suggested the convenience of integrating the two interventions into a multimodal treatment to boost and prolong the therapeutic outcomes. Such an approach is still in its infancy, and the physiological underpinnings substantiating the effectiveness and utility of combined interventions are still to be clarified. Therefore, this opinion paper aims to provide a theoretical framework consisting of compelling arguments as to why adding NIBS to psychotherapy can promote therapeutic change. Namely, we will discuss the physiological effects of the two interventions, thus providing a rationale to explain the potential advantages of a combined approach.

Pharmacological stimulation of infralimbic cortex after fear conditioning facilitates subsequent fear extinction

The infralimbic (IL) division of the medial prefrontal cortex (mPFC) is a crucial site for the extinction of conditioned fear memories in rodents. Recent work suggests that neuronal plasticity in the IL that occurs during (or soon after) fear conditioning enables subsequent IL-dependent extinction learning. We therefore hypothesized that pharmacological activation of the IL after fear conditioning would promote the extinction of conditioned fear. To test this hypothesis, we characterized the effects of post-conditioning infusions of the GABAA receptor antagonist, picrotoxin, into the IL on the extinction of auditory conditioned freezing in male and female rats. In four experiments, we found that picrotoxin injections performed immediately, 24 h, or 13 days after fear conditioning reduced conditioned freezing to the auditory conditioned stimulus (CS) during both extinction training and extinction retrieval; this effect was observed up to two weeks after picrotoxin infusions. Interestingly, inhibiting protein synthesis inhibition in the IL immediately after fear conditioning prevented the inhibition of freezing by picrotoxin injected 24 h later. Our data suggest that the IL encodes an inhibitory memory during the consolidation of fear conditioning that is necessary for future fear suppression.

The link between BDNF and platelets in neurological disorders

Platelets are considered one of the most important reservoirs not only of growth factors, but also of neurotrophic factors that could contribute to the repair of vascular lesions and the prevention of neurological deterioration. Among these factors, Brain-Derived Neurotrophic Factor (BDNF) - a protein belonging to the neurotrophin family - is widely expressed both in the hippocampus and in platelets. Platelets constitute an important reservoir of BDNF; however, little is known about the factors modulating its release into the circulation and whether anti-platelet drugs affect this secretion. In this review, we have discussed the link between BDNF and platelets and their role in neurological disorders.

Wnt-5a Signaling Mediates Metaplasticity at Hippocampal CA3-CA1 Synapses in Mice

Wnt signaling plays a role in synaptic plasticity, but the specific cellular events and molecular components involved in Wnt signaling-mediated synaptic plasticity are not well defined. Here, we report a change in the threshold required to induce synaptic plasticity that facilitates the induction of long-term potentiation (LTP) and inhibits the induction of long-term depression (LTD) during brief exposure to the noncanonical ligand Wnt-5a. Both effects are related to the metaplastic switch of hippocampal CA3-CA1 synaptic transmission, a complex mechanism underlying the regulation of the threshold required to induce synaptic plasticity and of synaptic efficacy. We observed an early increase in the amplitude of field excitatory postsynaptic potentials (fEPSPs) that persisted over time, including after washout. The first phase involves an increase in the fEPSP amplitude that is required to trigger a spontaneous second phase that depends on Jun N-terminal kinase (JNK) and N-methyl D-aspartate receptor (NMDAR) activity. These changes are prevented by treatment with secreted frizzled-related protein 2 (sFRP-2), an endogenous antagonist of Wnt ligands. Here, we demonstrate the contribution of Wnt-5a signaling to a process associated with metaplasticity at CA3-CA1 synapses that favors LTP over LTD.

The Val66Met variant of brain-derived neurotrophic factor is linked to reduced telomere length in a military population: a pilot study

In military populations, gene-environment interactions can influence performance and health outcomes. Brain-derived neurotrophic factor (BDNF) is a central nervous system protein that is important for neuronal function and synaptic plasticity. A BDNF single nucleotide polymorphism, rs6265, leads to an amino acid substitution of valine (Val) with methionine (Met) at codon 66 (Val66Met), which may influence an individual's response to occupational stress, and predispose military members to psychological disorders. Telomere length (TL), a novel measure of biological aging, can be used as a biomarker of stress. Accordingly, telomere shortening may be a surrogate indicator of physiological weathering due to chronic disease and stressful life events. To increase our understanding about the potential effect of the Val66Met mutation on the human stress response, we evaluated the relationships between Val66Met, TL, and mental health symptoms in a military population. In this pilot study (N = 164), we observed an association between Val66Met and reduced TL (p = 0.048). There was no relationship between Val66Met and mental health symptoms. These results support the investigation of gene-environment interactions, and their potential influence on TL due to occupational stress such as military service.

Altered Expression of Neuroplasticity-Related Genes in Alcohol Addiction and Treatment

Alcohol use disorder's complexity arises from genetic and environmental factors, with alcohol metabolism genes and neurotransmitter pathways being critical. This study aims to analyze synaptic plasticity gene expression changes in individuals with AUD in order to study their contribution to AUD development and to identify potential biomarkers of treatment response. RNA was extracted from whole peripheral blood (20 patients, 10 healthy controls), before and after treatment (Qiagen AllPrep RNA/DNA Mini Kit), and the gene expression of 84 genes related to neuroplasticity was studied using the RT2 Profiler for Human Synaptic Plasticity RT-PCR Array (PAHS-126ZA, Qiagen), comparing AUD patients to control and responders to non-responders. The potential prognostic/predictive biomarkers were searched using machine learning models. A total of 35 dysregulated genes were found in AUD patients. EPHB2, EGR, and AKT1 were increased, while TIMP1, NCAM1, and GRM2 were decreased. Responders showed distinct gene expression profiles at baseline. After treatment, the expression of 57 genes was normalized, while NCAM1, GRM2, and BDNF showed the most significant recovery. EGR4, INHBA, and NCAM1 emerged as potential biomarkers to predict treatment success. These results indicate that gene profiles in peripheral blood can serve as prognostic markers for the prognosis and treatment of AUD, although further validation is required.

The Protective Effects of Syringic Acid on Bisphenol A-Induced Neurotoxicity Possibly Through AMPK/PGC-1α/Fndc5 and CREB/BDNF Signaling Pathways

Bisphenol A (BPA), an endocrine disruptor, is commonly used to produce epoxy resins and polycarbonate plastics. Continuous exposure to BPA may contribute to the development of diseases in humans and seriously affect their health. Previous research suggests a significant relationship between the increased incidence of neurological diseases and the level of BPA in the living environment. Syringic acid (SA), a natural derivative of gallic acid, has recently considered much attention due to neuromodulator activity and its anti-oxidant, anti-apoptotic, and anti-inflammatory effects. Therefore, in this study, we aimed to investigate the effects of SA on oxidative stress, apoptosis, memory and locomotor disorders, and mitochondrial function, and to identify the mechanisms related to Alzheimer's disease (AD) in the brain of rats receiving high doses of BPA. For this purpose, male Wistar rats received BPA (50, 100, and 200 mg/kg) and SA (50 mg/kg) for 21 days. The results showed that BPA exposure significantly altered the rats' neurobehavioral responses. Additionally, BPA, by increasing the level of ROS, and MDA level, increased the level of oxidative stress while reducing the level of antioxidant enzymes, such as SOD, CAT, GPx, and mitochondrial GSH. The administration of BPA at 200 mg/kg significantly decreased the expression of ERRα, TFAM, irisin, PGC-1α, Bcl-2, and FNDC5, while it increased the expression of TrkB, cytochrome C, caspase 3, and Bax. Moreover, the Western blotting results showed that BPA increased the levels of P-AMPK, GSK3b, p-tau, and Aβ, while it decreased the levels of PKA, P-PKA, Akt, BDNF, CREB, P-CREB, and PI3K. Meanwhile, SA at 50 mg/kg reversed the behavioral, biochemical, and molecular changes induced by high doses of BPA. Overall, BPA could lead to the development of AD by affecting the mitochondria-dependent apoptosis pathway, as well as AMPK/PGC-1α/FNDC5 and CREB/BDNF/TrkB signaling pathways, and finally, by increasing the expression of tau and Aβ proteins. In conclusion, SA, as an antioxidant, significantly reduced the toxicity of BPA.

Repetitive transcranial magnetic stimulation via the hippocampal brain-derived neurotrophic factor-tyrosine kinase receptor B pathway to affect sexual behavior and neuroplasticity in rapid ejaculation rats

BACKGROUND

Premature ejaculation (PE) is the most prevalent sexual dysfunction among men. Eejaculation involves a complex nervous mechanism in which the ejaculatory centers play a key role in modulating sperm emission. Although treatment possibilities span from psychotherapy to pharmacological approaches, results show inconsistent efficacy. In this context, the emergence of repetitive transcranial magnetic stimulation (rTMS) as a non-invasive neuromodulatory approach represents a compelling avenue for potential therapeutic exploration.

OBJECTIVE

To investigate whether high-frequency transcranial magnetic stimulation can modulate the ejaculatory behavior of rats with rapid ejaculation by altering neurotransmitter levels and neuroplasticity in the hippocampus.

METHODS

Rats have been screened for rapid ejaculation by observing behavioral indices of mating, and subsequently divided into two groups. The intervention group was administered with a 10 Hz rTMS stimulation, whereas the control group received a sham procedure. Upon the delivery of rTMS, we investigated ejaculation latency (EL), the hippocampal 5-hydroxytryptamine (5-HT) concentration, brain-derived neurotrophic factor (BDNF), synaptophysin (SYN), and postsynaptic density protein 95 (PSD95) expressions, as well as BDNF-receptor tyrosine kinase receptor B (TrkB) pathway upregulation.

RESULTS

After 14 days, EL was increased in the intervention group compared with the control group. 5-HT concentration in the hippocampal region was increased, and high-frequency rTMS activated the BDNF and TrkB pathways, including phosphorylation of cAMP response element-binding protein (CREB), and upregulated the transcription and protein expression of SYN, and PSD95.

CONCLUSION

RTMS upregulates BDNF, SYN, and PSD95 expression through activation of the BDNF-TrkB pathway and increases brain 5-hydroxytryptamine thereby regulating neuroplasticity and improving ejaculation.

Neuron and astrocyte specific 5mC and 5hmC signatures of BDNF's receptor, TrkB

Brain derived neurotrophic factor (BDNF) is the most studied trophic factor in the central nervous system (CNS), and its role in the maturation of neurons, including synapse development and maintenance has been investigated intensely for over three decades. The primary receptor for BDNF is the tropomyosin receptor kinase B (TrkB), which is broadly expressed as two primary isoforms in the brain; the full length TrkB (TrkB.FL) receptor, expressed mainly in neurons and the truncated TrkB (TrkB.T1) receptor. We recently demonstrated that TrkB.T1 is predominately expressed in astrocytes, and appears critical for astrocyte morphological maturation. Given the critical role of BDNF/TrkB pathway in healthy brain development and mature CNS function, we aimed to identify molecular underpinnings of cell-type specific expression of each TrkB isoform. Using Nanopore sequencing which enables direct, long read sequencing of native DNA, we profiled DNA methylation patterns of the entire TrkB gene, Ntrk2, in both neurons and astrocytes. Here, we identified robust differences in cell-type specific isoform expression associated with significantly different methylation patterns of the Ntrk2 gene in each cell type. Notably, astrocytes demonstrated lower 5mC methylation, and higher 5hmC across the entire gene when compared to neurons, including differentially methylated sites (DMSs) found in regions flanking the unique TrkB.T1 protein coding sequence (CDS). These data suggest DNA methylation patterns may provide instruction for isoform specific TrkB expression across unique CNS cell types.

Connecting the emotional-cognitive puzzle: The role of tyrosine kinase B (TrkB) receptor isoform imbalance in age-related emotional and cognitive impairments

Age-related cognitive and affective disorders pose significant public health challenges. Notably, emotional and cognitive symptoms co-occur across multiple age-associated conditions like normal aging, Alzheimer's disease (AD), and mood disorders such as depression and anxiety. While the intricate interplay underlying this relationship remains poorly understood, this article highlights the possibility that an imbalance between full-length (TrkB.FL) and truncated (TrkB.T1) isoforms of tyrosine kinase receptor TrkB in the neurotrophic system may significantly affect age-associated emotional and cognitive functions, by altering brain-derived neurotrophic factor (BDNF) signaling, integral to neuronal health, cognitive functions and mood regulation. While the contribution of this imbalance to pathogenesis awaits full elucidation, this review evaluates its potential mediating role, linking emotional and cognitive decline across age-related disorders The interplay between TrkB.T1 and TrkB.FL isoforms may be considered as a pivotal shared regulator underlying this complex relationship. The current review aims to synthesize current knowledge on TrkB isoform imbalance, specifically its contribution to age-related cognitive decline and mood disorders. By examining shared pathogenic pathways between aging, cognitive decline, and mood disorders through the lens of TrkB signaling, this review uncovers potential therapeutic targets not previously considered, offering a fresh perspective on combating age-related mental health issues as well as cognitive deficits.

Regional-specific changes in rat brain BDNF in a model of methamphetamine abuse

Brain-derived neurotrophic factor (BDNF), a member of the neurotrophin family, plays key roles in neuronal protection and synaptic plasticity. Changes in BDNF are associated with various pathological conditions, including methamphetamine (meth) addiction, although the effects of meth on BDNF expression are not always consistent. We have previously demonstrated region-specific effects of a chronic meth regime on BDNF methylation and expression in the rat brain. This study aims to determine the effect of chronic meth administration on the expression of BDNF protein using immunohistochemistry in the rat frontal cortex and hippocampus. Novel object recognition (NOR) as a measure of cognitive function was also determined. Male Sprague Dawley rats were administered a chronic escalating dose (0.1-4 mg/kg over 14 days) (ED) of meth or vehicle; a subgroup of animals receiving meth were also given an acute "binge" (4x6mg) dose on the final day before NOR testing. The results showed that hippocampal CA1 BDNF protein was significantly increased by 72 % above control values in the ED-binge rats, while other hippocampal regions and frontal cortex were not significantly affected. Meth-administered animals also demonstrated deficits in NOR after 24 h delay. No significant effect of the additional binge dose on BDNF protein or NOR findings was apparent. This finding is consistent with our previous results of reduced DNA methylation and increased expression of the BDNF gene in this region. The hippocampal BDNF increase may reflect an initial increase in a protective factor produced in response to elevated glutamate release resulting in neurodegenerative excitotoxicity.

Diet/photoperiod mediated changes in cerebellar clock genes causes locomotor shifts and imperative changes in BDNF-TrkB pathway

Neuropsychological studies report anxiety and depression like symptoms in patients suffering from lifestyle disorder but its impact on locomotor function lacks clarity. Our study investigates locomotor deficits resulting due to perturbations in cerebellum of high fat diet (HFD), chronodisruption (CD) or a combination (HCD) model of lifestyle disorder. Significant downregulation in levels of cerebellar clock genes (Bmal-1, Clock, Per 1 and Per 2) and Bdnf-Trkb pathway genes (Bdnf, TrkB and Syn1 levels) were recorded. Further, locomotor deficits were observed in all the three experimental groups as evidenced by actimeter test, pole test and wire hanging test. Nuclear pyknosis of Purkinje cells, their derangement and inflammation were the hallmark of cerebellar tissue of all the three experimental groups. Taken together, this study generates important links between cerebellar clock oscillations, locomotor function and Bdnf-TrkB signaling.

Blueberry extracts antagonize Aβ25-35 neurotoxicity and exert a neuroprotective effect through MEK-ERK-BDNF/UCH-L1 signaling pathway in rat and mouse hippocampus

BACKGROUND

The neuroprotective potential of blueberry (BB) extracts against Alzheimer's disease (AD) has been previously hinted at, while its exact mechanism has remained largely enigmatic.

OBJECTIVE

Our study endeavored to unravel the impacts and mechanisms by which BB extracts ameliorated the learning and memory prowess of AD-afflicted mice, with a specific focus on the MEK-ERK pathway.

METHODS

We employed 3-month-old APP/PS1 transgenic mice and stratified them into three distinct groups: AD+BB, AD, and control (CT). The Morris Water Maze Test (MWMT) was then administered to gauge their learning and memory faculties. In vitro experiments were executed on Aβ25-35-afflicted rat hippocampal neurons, which were subsequently treated with varying concentrations of BB extracts. We then assessed the expression levels of genes and proteins integral to the MEK-ERKBDNF/UCH-L1 pathway.

RESULTS

The data showed that the AD mice demonstrated compromised learning and memory faculties in MWMT. However, the AD+BB cohort showcased marked improvements in performance. Furthermore, in the AD subset, significant elevations in the expressions of MEK2 and ERK1/2 were observed, both at the mRNA and protein levels. Conversely, UCH-L1 mRNA expressions exhibited a decline, while BDNF expressions surged significantly. However, post BB extract treatment, the expressions of MEK2 and ERK1/2 were subdued, with UCH-L1 and BDNF mRNA expressions reverting to control levels.

CONCLUSIONS

Our findings propounded that BB extracts could offer therapeutic promise for AD by bolstering learning and memory capacities. The unwarranted activation of the MEK-ERK pathway, coupled with the aberrant expressions of BDNF and UCH-L1, might underpin AD's pathogenesis.

Impaired synaptic plasticity and decreased glutamatergic neuron excitability induced by SIRT1/BDNF downregulation in the hippocampal CA1 region are involved in postoperative cognitive dysfunction

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a common complication after anesthesia/surgery, especially among elderly patients, and poses a significant threat to their postoperative quality of life and overall well-being. While it is widely accepted that elderly patients may experience POCD following anesthesia/surgery, the exact mechanism behind this phenomenon remains unclear. Several studies have indicated that the interaction between silent mating type information regulation 2 homologue 1 (SIRT1) and brain-derived neurotrophic factor (BDNF) is crucial in controlling cognitive function and is strongly linked to neurodegenerative disorders. Hence, this research aims to explore how SIRT1/BDNF impacts cognitive decline caused by anesthesia/surgery in aged mice.

METHODS

Open field test (OFT) was used to determine whether anesthesia/surgery affected the motor ability of mice, while the postoperative cognitive function of 18 months old mice was evaluated with Novel object recognition test (NORT), Object location test (OLT) and Fear condition test (FC). The expressions of SIRT1 and other molecules were analyzed by western blot and immunofluorescence staining. The hippocampal synaptic plasticity was detected by Golgi staining and Long-term potentiation (LTP). The effects of SIRT1 and BDNF overexpression as well as chemogenetic activation of glutamatergic neurons in hippocampal CA1 region of 18 months old vesicular glutamate transporter 1 (VGLUT1) mice on POCD were further investigated.

RESULTS

The research results revealed that older mice exhibited cognitive impairment following intramedullary fixation of tibial fracture. Additionally, a notable decrease in the expression of SIRT1/BDNF and neuronal excitability in hippocampal CA1 glutamatergic neurons was observed. By increasing levels of SIRT1/BDNF or enhancing glutamatergic neuron excitability in the CA1 region, it was possible to effectively mitigate synaptic plasticity impairment and ameliorate postoperative cognitive dysfunction.

CONCLUSIONS

The decline in SIRT1/BDNF levels leading to changes in synaptic plasticity and neuronal excitability in older mice could be a significant factor contributing to cognitive impairment after anesthesia/surgery.

Beneficial effects of metformin treatment on memory impairment

Memory issues are a prevalent symptom in different neurodegenerative diseases and can also manifest in certain psychiatric conditions. Despite limited medications approved for treating memory problems, research suggests a lack of sufficient options in the market. Studies indicate that a significant percentage of elderly individuals experience various forms of memory disorders. Metformin, commonly prescribed for type 2 diabetes, has shown neuroprotective properties through diverse mechanisms. This study explores the potential of metformin in addressing memory impairments. The current research gathered its data by conducting an extensive search across electronic databases including PubMed, Web of Science, Scopus, and Google Scholar. Previous research suggests that metformin enhances brain cell survival and memory function in both animal and clinical models by reducing oxidative stress, inflammation, and cell death while increasing beneficial neurotrophic factors. The findings of the research revealed that metformin is an effective medication for enhancing various types of memory problems in numerous studies. Given the rising incidence of memory disorders, it is plausible to utilize metformin, which is an affordable and accessible drug. It is often recommended as a treatment to boost memory.

BDNF Signaling in Vascular Dementia and Its Effects on Cerebrovascular Dysfunction, Synaptic Plasticity, and Cholinergic System Abnormality

Vascular dementia (VaD) is the second most common type of dementia and is characterized by memory impairment, blood-brain barrier disruption, neuronal cell loss, glia activation, impaired synaptic plasticity, and cholinergic system abnormalities. To effectively prevent and treat VaD a good understanding of the mechanisms underlying its neuropathology is needed. Brain-derived neurotrophic factor (BDNF) is an important neurotrophic factor with multiple functions in the systemic circulation and the central nervous system and is known to regulate neuronal cell survival, synaptic formation, glia activation, and cognitive decline. Recent studies indicate that when compared with normal subjects, patients with VaD have low serum BDNF levels and that BDNF deficiency in the serum and cerebrospinal fluid is an important indicator of VaD. Here, we review current knowledge on the role of BDNF signaling in the pathology of VaD, such as cerebrovascular dysfunction, synaptic dysfunction, and cholinergic system impairment.

The concept of resilience to Alzheimer's Disease: current definitions and cellular and molecular mechanisms

Some individuals are able to maintain their cognitive abilities despite the presence of significant Alzheimer's Disease (AD) neuropathological changes. This discrepancy between cognition and pathology has been labeled as resilience and has evolved into a widely debated concept. External factors such as cognitive stimulation are associated with resilience to AD, but the exact cellular and molecular underpinnings are not completely understood. In this review, we discuss the current definitions used in the field, highlight the translational approaches used to investigate resilience to AD and summarize the underlying cellular and molecular substrates of resilience that have been derived from human and animal studies, which have received more and more attention in the last few years. From these studies the picture emerges that resilient individuals are different from AD patients in terms of specific pathological species and their cellular reaction to AD pathology, which possibly helps to maintain cognition up to a certain tipping point. Studying these rare resilient individuals can be of great importance as it could pave the way to novel therapeutic avenues for AD.

Symptomatic remission and recovery in major psychosis: Is there a role for BDNF? A secondary analysis of the LABSP cohort data

Remission, relapse prevention, and clinical recovery are crucial areas of interest in schizophrenia (SCZ) research. Although SCZ is a chronic disorder with poor overall outcomes, years of research demonstrated that recovery is possible. There are considerable data linking brain-derived neurotrophic factor (BDNF) to SCZ, however, evidence on the role of BDNF in remission in SCZ is scarce. This secondary analysis of the Longitudinal Assessment of BDNF in Sardinian patients (LABSP) data aimed to investigate the relationship between serum BDNF levels and symptomatic remission, simultaneous clinical and functional remission, and recovery in patients with SCZ. A total of 105 patients with SCZ or schizoaffective disorder were recruited for a longitudinal assessment of BDNF levels over 24 months. Longitudinal data were analyzed using mixed-effects linear regression models. The study found significant associations between use of long acting injectables (χ2 = 7.075, df = 1, p = 0.008), baseline serum BDNF levels (U = 701, z = -2.543, p = 0.011), and "childhood" (U = 475, z = -2.124, p = 0.034) and "general" (U = 55, z = -2.014, p = 0.044) subscales of the Premorbid Adjustment Scale (PAS) with patients maintaining remission and recovery. The diagnosis of SCZ was significantly associated with lower BDNF levels for patients with simultaneous clinical and functional remission (Z = 2.035, p = 0.0419) and recovery (Z = 2.009, p = 0.0445) compared to those without. There were no significant associations between remission in the entire sample and longitudinal serum BDNF levels or genetic variants within the BDNF gene. These findings provide further insight into the complex relationship between BDNF and SCZ.

The dose-dependent neuroprotective effect of norepinephrine in improving memory retrieval in an experimental model of multiple sclerosis, experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is considered an immune-mediated inflammatory disorder that causes cognitive impairments by damaging the hippocampal tissue. Conversely, norepinephrine (NEP) has anti-inflammatory and re-myelinating properties, which improve cognitive impairments. The aim of this study was to assess the neuroprotective effects of NEP on learning and memory disorders in an experimental animal model of MS. Two guide cannulas were bilaterally implanted in the rat hippocampal CA1 regions. After recovery, the animals received 3 μl of 0.01% ethidium bromide (EtB) in each of both hippocampal regions. After three days, the rats were randomly divided into 6 groups (8 rats/group), including control, sham 1, sham 2, and three groups of NEP 0.25, 0.5, and 1 mg/kg by intrahippocampal injection. Behavioral tests (e.g. shuttle box test and open-field test) were then performed. Finally, ROS, MDA, GSH, TNF-α, IL-6, and IL-1β concentrations in the left CA1 area, as well as using western-blot analysis, p-p38, p-JNK, p-AKT, p-ERK1/2, p-NMDA, p-AMPA, p-CREB, and BDNF proteins in the right CA1 region evaluated. The EtB injection increased ROS, MDA, TNF-α, IL-6, and IL-1β levels, as well as p-JNK and p-P38, except all other proteins, while decreasing GSH content, as well as step-through latency and locomotor activity in sham groups compared to the control group. Conversely, NEP (0.5 and 1 mg/kg, particularly at the dose of 1 mg/kg) counterbalanced all the alterations mentioned above in comparison to the sham groups. The EtB induced learning and memory impairment; however, NEP dose-dependently restored these impairments to normal levels.

Pharmacological stimulation of infralimbic cortex after fear conditioning facilitates subsequent fear extinction

The infralimbic (IL) division of the medial prefrontal cortex (mPFC) is a crucial site for extinction of conditioned fear memories in rodents. Recent work suggests that neuronal plasticity in the IL that occurs during (or soon after) fear conditioning enables subsequent IL-dependent extinction learning. We therefore hypothesized that pharmacological activation of the IL after fear conditioning would promote the extinction of conditioned fear. To test this hypothesis, we characterized the effects of post-conditioning infusions of the GABAA receptor antagonist, picrotoxin, into the IL on extinction of auditory conditioned freezing in male and female rats. In four experiments, we found that picrotoxin injections performed immediately, 24 hours, or 13 days after fear conditioning reduced conditioned freezing to the auditory conditioned stimulus (CS) during both extinction training and extinction retrieval; this effect was observed up to two weeks after picrotoxin infusions. Interestingly, inhibiting protein synthesis inhibition in the IL immediately after fear conditioning prevented the inhibition of freezing by picrotoxin injected 24 hours later. Our data suggest that the IL encodes an inhibitory memory during the consolidation of fear conditioning that is necessary for future fear suppression.

The Influence of Neurotrophins on the Brain-Lung Axis: Conception, Pregnancy, and Neonatal Period

Neurotrophins (NTs) are four small proteins produced by both neuronal and non-neuronal cells; they include nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4). NTs can exert their action through both genomic and non-genomic mechanisms by interacting with specific receptors. Initial studies on NTs have identified them only as functional molecules of the nervous system. However, recent research have shown that some tissues and organs (such as the lungs, skin, and skeletal and smooth muscle) as well as some structural cells can secrete and respond to NTs. In addition, NTs perform several roles in normal and pathological conditions at different anatomical sites, in both fetal and postnatal life. During pregnancy, NTs are produced by the mother, placenta, and fetus. They play a pivotal role in the pre-implantation process and in placental and embryonic development; they are also involved in the development of the brain and respiratory system. In the postnatal period, it appears that NTs are associated with some diseases, such as sudden infant death syndrome (SIDS), asthma, congenital central hypoventilation syndrome (CCHS), and bronchopulmonary dysplasia (BPD).

Sex-specific regulation of the cortical transcriptome in response to sleep deprivation

Multiple studies have documented sex differences in sleep behaviour, however, the molecular determinants of such differences remain unknown. Furthermore, most studies addressing molecular mechanisms have been performed only in males, leaving the current state of knowledge biased towards the male sex. To address this, we studied the differences in the transcriptome of the cerebral cortex of male and female C57Bl/6 J mice after 6 h of sleep deprivation. We found that several genes, including the neurotrophin growth factor Bdnf, immediate early genes Fosb and Fosl2, and the adenylate cyclase Adcy7 are differentially upregulated in males compared to females. We identified the androgen-receptor activating transcription factor EZH2 as the upstream regulatory element specifying sex differences in the sleep deprivation transcriptome. We propose that the pathways downstream of these transcripts, which impact on cellular re-organisation, synaptic signalling, and learning may underpin the differential response to sleep deprivation in the two sexes.

Baseline serum brain-derived neurotrophic factor association with future cognition in community-dwelling older adults undergoing annual memory screening

OBJECTIVES

It has been shown that peripheral measures of brain-derived neurotrophic factor (BNDF), an important neurotrophin instrumental to the biology of learning, may contribute to predicting cognitive decline. However, the two primary forms of BDNF, mature (mBDNF) and pro (proBDNF), and how they contribute to cognition longitudinally has not been well studied.

METHODS

Eighty-two older adults (average age 72.2 ± 6.4 years) provided blood samples at two time points separated on average by 4.2 years while participating in an annual memory screening that included the MoCA (Montreal Cognitive Assessment) and GDS (Geriatric Depression Scale). Both mBDNF and proBDNF from serum were quantified at each time point. Whole blood samples were genotyped for APOE and BDNF Val66Met.

RESULTS

Using logistic regression analysis controlling for age, sex, baseline MoCA score, APOE, and BDNF, higher baseline mBDNF was associated with subjects whose screening score was near maximum or maximum (as defined by MoCA score of 29 or 30) at the second collection visit. APOE was a significant contributing factor; however, BDNF Val66Met was not. Using a similar logistic regression analysis, baseline proBDNF was not found to be associated with future cognition.

DISCUSSION

This study further supports that mBDNF measured in the serum of older adults may reflect a protective role while proBDNF requires further investigation.

Early Detection of Amyloid-Related Changes in Memory among Cognitively Unimpaired Older Adults with Daily Digital Testing

OBJECTIVE

This study was undertaken to determine whether assessing learning over days reveals Alzheimer disease (AD) biomarker-related declines in memory consolidation that are otherwise undetectable with single time point assessments.

METHODS

Thirty-six (21.9%) cognitively unimpaired older adults (aged 60-91 years) were classified with elevated β-amyloid (Aβ+) and 128 (78%) were Aβ- using positron emission tomography with 11C Pittsburgh compound B. Participants completed the multiday Boston Remote Assessment for Neurocognitive Health (BRANCH) for 12 min/day on personal devices (ie, smartphones, laptops), which captures the trajectory of daily learning of the same content on 3 repeated tests (Digit Signs, Groceries-Prices, Face-Name). Learning is computed as a composite of accuracy across all 3 measures. Participants also completed standard in-clinic cognitive tests as part of the Preclinical Alzheimer's Cognitive Composite (PACC-5), with 123 participants undergoing PACC-5 follow-up after 1.07 (standard deviation = 0.25) years.

RESULTS

At the cross-section, there were no statistically significant differences in performance between Aβ+/- participants on any standard in-clinic cognitive tests (eg, PACC-5) or on day 1 of multiday BRANCH. Aβ+ participants exhibited diminished 7-day learning curves on multiday BRANCH after 4 days of testing relative to Aβ- participants (Cohen d = 0.49, 95% confidence interval = 0.10-0.87). Diminished learning curves were associated with greater annual PACC-5 decline (r = 0.54, p < 0.001).

INTERPRETATION

Very early Aβ-related memory declines can be revealed by assessing learning over days, suggesting that failures in memory consolidation predate other conventional amnestic deficits in AD. Repeated digital memory assessments, increasingly feasible and uniquely able to assess memory consolidation over short time periods, have the potential to be transformative for detecting the earliest cognitive changes in preclinical AD. ANN NEUROL 2024;95:507-517.

Cellular and Molecular Mechanisms Underlying Synaptic Subcellular Specificity

Chemical synapses are essential for neuronal information storage and relay. The synaptic signal received or sent from spatially distinct subcellular compartments often generates different outcomes due to the distance or physical property difference. Therefore, the final output of postsynaptic neurons is determined not only by the type and intensity of synaptic inputs but also by the synaptic subcellular location. How synaptic subcellular specificity is determined has long been the focus of study in the neurodevelopment field. Genetic studies from invertebrates such as Caenorhabditis elegans (C. elegans) have uncovered important molecular and cellular mechanisms required for subcellular specificity. Interestingly, similar molecular mechanisms were found in the mammalian cerebellum, hippocampus, and cerebral cortex. This review summarizes the comprehensive advances in the cellular and molecular mechanisms underlying synaptic subcellular specificity, focusing on studies from C. elegans and rodents.

Epigenetic mechanisms of nicotine dependence

Smoking continues to be a leading cause of preventable disease and death worldwide. Nicotine dependence generates a lifelong propensity towards cravings and relapse, presenting an ongoing challenge for the development of treatments. Accumulating evidence supports a role for epigenetics in the development and maintenance of addiction to many drugs of abuse, however, the involvement of epigenetics in nicotine dependence is less clear. Here we review evidence that nicotine interacts with epigenetic mechanisms to enable the maintenance of nicotine-seeking across time. Research across species suggests that nicotine increases permissive histone acetylation, decreases repressive histone methylation, and modulates levels of DNA methylation and noncoding RNA expression throughout the brain. These changes are linked to the promoter regions of genes critical for learning and memory, reward processing and addiction. Pharmacological manipulation of enzymes that catalyze core epigenetic modifications regulate nicotine reward and associative learning, demonstrating a functional role of epigenetic modifications in nicotine dependence. These findings are consistent with nicotine promoting an overall permissive chromatin state at genes important for learning, memory and reward. By exploring these links through next-generation sequencing technologies, epigenetics provides a promising avenue for future interventions to treat nicotine dependence.

[The relationship between the rs6265 polymorphism of the BDNF gene and the level of serum neurotrophic factor in patients with Parkinson's disease]

OBJECTIVE

To evaluate the clinical features and the level of serum brain-derived neurotrophic factor (BDNF) in groups of patients with Parkinson's disease (PD) differentiated by the genotypes of BDNF polymorphism (rs6265).

MATERIAL AND METHODS

The level of serum BDNF in the biomarkers' multiplex panel of neurodegenerative diseases (HNDG3MAG-36K) was assessed in 134 PD patients. Allele discrimination was carried out by real-time PCR using TaqMan probes for the analysis of BDNF rs6265 polymorphism in groups of patients and controls (n=192) matched for sex, age and ethnicity.

RESULTS

Comparing the distribution of rs6265 genotypes and alleles between groups of patients and controls no significant differences were found (p>0.05). Serum BDNF levels varied significantly by genotype (rs6265) among PD patients. Minimum mean serum BDNF level (320.1±164.6 pg/ml) was noted for individuals with the AA genotype, which significantly differs from the corresponding indicator among individuals with GA (2944.2±1590.6 pg/ml; p=0.0001) and GG genotypes (2949.4±1620.6 pg/ml; p=3.9×10-5). The concentration of BDNF significantly differed between patients with different forms of PD (p=0.0007) and increased as the stage of the disease progressed according to Hoehn and Yahr staging scale (p=1.0×10-6).

CONCLUSION

The BDNF rs6265 polymorphism was not associated with the development of PD in the studied population. The variability of the mean serum BDNF level was established depending on the genotype of the BDNF polymorphism in PD patients and a number of clinical features.

Low-intensity pulsed ultrasound enhances neurite growth in serum-starved human neuroblastoma cells

Introduction

Low-intensity pulsed ultrasound (LIPUS) is a recognized tool for promoting nerve regeneration and repair; however, the intracellular mechanisms of LIPUS stimulation remain underexplored.

Method

The present study delves into the effects of varying LIPUS parameters, namely duty cycle, spatial average-temporal average (SATA) intensity, and ultrasound amplitude, on the therapeutic efficacy using SK-N-SH cells cultured in serum-starved conditions. Four distinct LIPUS settings were employed: (A) 50 mW/cm2, 40%, (B) 25 mW/cm2, 10%, (C) 50 mW/cm2, 20%, and (D) 25 mW/cm2, 10%.

Results

Immunochemistry analysis exhibited neurite outgrowth promotion in all LIPUS-treated groups except for Group D. Further, LIPUS treatment was found to successfully promote brain-derived neurotrophic factor (BDNF) expression and enhance the phosphorylation of extracellular signal-regulated kinase (ERK)1/2, protein kinase B (Akt), and mammalian target of rapamycin (mTOR) signaling pathways, as evidenced by western blot analysis.

Discussion

The study suggests that the parameter combination of LIPUS determines the therapeutic efficacy of LIPUS. Future investigations should aim to optimize these parameters for different cell types and settings and delve deeper into the cellular response mechanism to LIPUS treatment. Such advancements may aid in tailoring LIPUS treatment strategies to specific therapeutic needs.

Neuroprotective Effects of Davallia mariesii Roots and Its Active Constituents on Scopolamine-Induced Memory Impairment in In Vivo and In Vitro Studies

Beta-amyloid (Aβ) proteins, major contributors to Alzheimer's disease (AD), are overproduced and accumulate as oligomers and fibrils. These protein accumulations lead to significant changes in neuronal structure and function, ultimately resulting in the neuronal cell death observed in AD. Consequently, substances that can inhibit Aβ production and/or accumulation are of great interest for AD prevention and treatment. In the course of an ongoing search for natural products, the roots of Davallia mariesii T. Moore ex Baker were selected as a promising candidate with anti-amyloidogenic effects. The ethanol extract of D. mariesii roots, along with its active constituents, not only markedly reduced Aβ production by decreasing β-secretase expression in APP-CHO cells (Chinese hamster ovary cells which stably express amyloid precursor proteins), but also exhibited the ability to diminish Aβ aggregation while enhancing the disaggregation of Aβ aggregates, as determined through the Thioflavin T (Th T) assay. Furthermore, in an in vivo study, the extract of D. mariesii roots showed potential (a tendency) for mitigating scopolamine-induced memory impairment, as evidenced by results from the Morris water maze test and the passive avoidance test, which correlated with reduced Aβ deposition. Additionally, the levels of acetylcholine were significantly elevated, and acetylcholinesterase levels significantly decreased in the brains of mice (whole brains). The treatment with the extract of D. mariesii roots also led to upregulated brain-derived neurotrophic factor (BDNF) and phospho-cAMP response element-binding protein (p-CREB) in the hippocampal region. These findings suggest that the extract of D. mariesii roots, along with its active constituents, may offer neuroprotective effects against AD. Consequently, there is potential for the development of the extract of D. mariesii roots and its active constituents as effective therapeutic or preventative agents for AD.

Control of Selective mRNA Translation in Neuronal Subcellular Compartments in Health and Disease

In multiple cell types, mRNAs are transported to subcellular compartments, where local translation enables rapid, spatially localized, and specific responses to external stimuli. Mounting evidence has uncovered important roles played by local translation in vivo in axon survival, axon regeneration, and neural wiring, as well as strong links between dysregulation of local translation and neurologic disorders. Omic studies have revealed that >1000 mRNAs are present and can be selectively locally translated in the presynaptic and postsynaptic compartments from development to adulthood in vivo A large proportion of the locally translated mRNAs is specifically upregulated or downregulated in response to distinct extracellular signals. Given that the local translatome is large, selectively translated, and cue-specifically remodeled, a fundamental question concerns how selective translation is achieved locally. Here, we review the emerging regulatory mechanisms of local selective translation in neuronal subcellular compartments, their mRNA targets, and their orchestration. We discuss mechanisms of local selective translation that remain unexplored. Finally, we describe clinical implications and potential therapeutic strategies in light of the latest advances in gene therapy.

Biosensors, Recent Advances in Determination of BDNF and NfL

Key biomarkers such as Brain Derived Neurotrophic Factor (BDNF) and Neurofilament light chain (NfL) play important roles in the development and progression of many neurological diseases, including multiple sclerosis, Alzheimer's disease, and Parkinson's disease. In these clinical conditions, the underlying biomarker processes are markedly heterogeneous. In this context, robust biomarker discovery is of critical importance for screening, early detection, and monitoring of neurological diseases. The difficulty of directly identifying biochemical processes in the central nervous system (CNS) is challenging. In recent years, biomarkers of CNS inflammatory response have been identified in various body fluids such as blood, cerebrospinal fluid, and tears. Furthermore, biotechnology and nanotechnology have facilitated the development of biosensor platforms capable of real-time detection of multiple biomarkers in clinically relevant samples. Biosensing technology is approaching maturity and will be deployed in communities, at which point screening programs and personalized medicine will become a reality. In this multidisciplinary review, our goal is to highlight clinical and current technological advances in the development of multiplex-based solutions for effective diagnosis and monitoring of neuroinflammatory and neurodegenerative diseases. The trend in the detection if BDNF and NfL.

The effect of supraphysiological dose of nandrolone decanoate administration on the inflammatory, neurotrophin and behavioral response in adult and old male mice

This study examined the effect of 6 weeks of supraphysiological nandrolone decanoate (ND) administration in adult mice (7 months) on cognitive function and neuroinflammation during aging. Male C57BL/6 mice were randomized into ND (10 mg·kg-1·wk-1) or control (CTL) groups. Half of the mice were tested at a young (Y) age (ND-Y and CTL-Y), 1 week following final ND administration, while the remaining mice were tested at 16 months (O) (ND-O and CTL-O). Learning and memory were better in young mice compared to older mice, regardless of treatment. ND-O displayed decreased anxiety as compared to all other groups. TNFα and IL1β expression were higher in older mice, regardless of treatment. ND administration in young mice appeared to attenuate the neuroinflammatory response in aging mice as evidenced by decreased COX2, IL-4 and increased IL-10 expression in ND-O compared to CTL-O. BDNF AR and ER expression increased in ND-O compared to CTL-O. Results of the study indicated that supraphysiological ND administration had no negative effect on learning and memory but may attenuate anxiety in older mice. In addition, ND administration in young adult mice may attenuate the inflammatory response during aging, which may be related to elevations in both AR and ER expression.

VPS13A knockdown impairs corticostriatal synaptic plasticity and locomotor behavior in a new mouse model of chorea-acanthocytosis

Chorea-acanthocytosis (ChAc) is an inherited neurodegenerative movement disorder caused by VPS13A gene mutations leading to the absence of protein expression. The striatum is the most affected brain region in ChAc patients. However, the study of the VPS13A function in the brain has been poorly addressed. Here we generated a VPS13A knockdown (KD) model and aimed to elucidate the contribution of VPS13A to synaptic plasticity and neuronal communication in the corticostriatal circuit. First, we infected primary cortical neurons with miR30-shRNA against VPS13A and analyzed its effects on neuronal plasticity. VPS13A-KD neurons showed a higher degree of branching than controls, accompanied by decreased BDNF and PSD-95 levels, indicative of synaptic alterations. We then injected AAV-KD bilaterally in the frontal cortex and two different regions of the striatum of mice and analyzed the effects of VPS13A-KD on animal behavior and synaptic plasticity. VPS13A-KD mice showed modification of the locomotor behavior pattern, with increased exploratory behavior and hyperlocomotion. Corticostriatal dysfunction in VPS13A-KD mice was evidenced by impaired striatal long-term depression (LTD) after stimulation of cortical afferents, which was partially recovered by BDNF administration. VPS13A-KD did not lead to neuronal loss in the cortex or the striatum but induced a decrease in the neuronal release of CX3CL1 and triggered a microglial reaction, especially in the striatum. Notably, CX3CL1 administration partially restored the impaired corticostriatal LTD in VPS13A-KD mice. Our results unveil the involvement of VPS13A in neuronal connectivity modifying BDNF and CX3CL1 release. Moreover, the involvement of VPS13A in synaptic plasticity and motor behavior provides key information to further understand not only ChAc pathophysiology but also other neurological disorders.

Forniceal deep brain stimulation in a mouse model of Rett syndrome increases neurogenesis and hippocampal memory beyond the treatment period

BACKGROUND

Rett syndrome (RTT), caused by mutations in the X-linked gene encoding methyl-CpG binding protein 2 (MeCP2), severely impairs learning and memory. We previously showed that forniceal deep brain stimulation (DBS) stimulates hippocampal neurogenesis with concomitant improvements in hippocampal-dependent learning and memory in a mouse model of RTT.

OBJECTIVES

To determine the duration of DBS benefits; characterize DBS effects on hippocampal neurogenesis; and determine whether DBS influences MECP2 genotype and survival of newborn dentate granular cells (DGCs) in RTT mice.

METHODS

Chronic DBS was delivered through an electrode implanted in the fimbria-fornix. We tested separate cohorts of mice in contextual and cued fear memory at different time points after DBS. We then examined neurogenesis, DGC apoptosis, and the expression of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) after DBS by immunohistochemistry.

RESULTS

After two weeks of forniceal DBS, memory improvements lasted between 6 and 9 weeks. Repeating DBS every 6 weeks was sufficient to maintain the improvement. Forniceal DBS stimulated the birth of more MeCP2-positive than MeCP2-negative DGCs and had no effect on DGC survival. It also increased the expression of BDNF but not VEGF in the RTT mouse dentate gyrus.

CONCLUSION

Improvements in learning and memory from forniceal DBS in RTT mice extends well beyond the treatment period and can be maintained by repeated DBS. Stimulation of BDNF expression correlates with improvements in hippocampal neurogenesis and memory benefits.