BDNF signaling: Harnessing stress to battle mood disorder

Intranasal AdipoRon mitigates motor and cognitive deficits in hemiparkinsonian rats through neuroprotective mechanisms against oxidative stress and synaptic dysfunction

While motor symptoms are the most well-known manifestation of Parkinson's disease (PD), patients may also suffer from non-motor signs like cognitive impairments. The adiponectin receptor agonist AdipoRon (Adipo) has shown neuroprotective effects in preclinical studies. The objective of this study was to determine the potential benefits of chronic intranasal treatment of Adipo on motor function and cognitive performance in a hemiparkinsonian rat model caused by injecting 6-hydroxydopamine (6-OHDA) into the left forebrain bundle. After one week, PD rats were given either a vehicle or one of three dosages of Adipo (0.1, 1, and 10 μg) or levodopa (10 mg/kg orally) daily for 21 days. Recognition and spatial memory were determined using the novel object recognition test (NORT) and the Barnes maze test, respectively. The hippocampal tissues of the animals were harvested to examine oxidative stress status as well as the protein expressions of brain-derived neurotrophic factor (BDNF) and postsynaptic density protein 95 (PSD-95). In hemiparkinsonian rats, motor impairments, recognition memory, and spatial memory were all improved by chronic intranasal Adipo at 1 and 10 μg. Furthermore, we found that unilateral 6-OHDA injection elevated hippocampal oxidative stress (ROS) while concurrently reducing total antioxidant capacity (TAC), BDNF, PSD-95, and antioxidant enzymes (SOD, GPx). However, Adipo 10 μg significantly reduced these biochemical alterations in the hippocampus of 6-OHDA-lesioned rats. Chronic intranasal Adipo ameliorated spatial and recognition memory deterioration in hemiparkinsonian rats, presumably by increasing hippocampal synaptic protein levels, reducing oxidative stress, and increasing BDNF.

New Insights into Contradictory Changes in Brain-Derived Neurotrophic Factor (BDNF) in Rodent Models of Posttraumatic Stress Disorder (PTSD)

Post-traumatic stress disorder (PTSD) is a neuropsychiatric disorder that may develop after experiencing traumatic events. Preclinical studies use various methods to induce PTSD-like models such as fear-conditioning, single-prolonged stress (SPS), restraint stress, and social defeat. Brain-derived neurotrophic factor (BDNF) is a crucial neurotrophin in mood regulation. Evidence shows BDNF changes in different neuropsychiatric disorders particularly PTSD. This review examined BDNF alterations in preclinical rodent models of PTSD where we demonstrated a wide range of paradoxical changes in BDNF. We found that the fear-conditioning model produced the most inconsistent alterations in BDNF, and suggest that conclusions drawn from these changes be approached with caution. We suggest that BDNF maladaptive changes in social defeat and restraint stress models may be related to the duration of stress, while the SPS model appears to have more consistent results. Ultimately, we propose that evaluating BDNF alterations in the process of treating PTSD symptoms may not be a reliable factor.

New insights into individual differences in response to chronic unpredictable mild stress (CUMS) in rats with respect to hippocampal BDNF and GSK3-β expression levels

Preclinical and clinical studies have shown a wide-range of individual differences in response to stressors or novel environments which can affect the susceptibility to develop abnormal behaviors and neuropsychiatric disorders. Both vulnerability and resiliency have been observed in animals and humans experiencing stressful events. Chronic unpredictable mild stress (CUMS) is a rodent depression model consisting of various stressors. This protocol leads to depressive- and anhedonic-like behaviors in rodents. The present study aimed to evaluate potential individual differences in response to CUMS in rats, with respect to the expression level of brain-derived neurotrophic factor (BDNF) and glycogen synthase kinases 3-beta (GSK3-β) (proteins involved in the modulation of mood, neuroplasticity, and cognition) in the hippocampus. CUMS was performed for four consecutive weeks. Depressive-like behavior, locomotor activity, anxiety-like behavior, and pain threshold were also evaluated using forced swim test (FST), open field test (OFT), and the hot plate (HP), respectively. Real-time PCR was used to evaluate BDNF and GSK3-β expression levels. The results showed that CUMS rats can be classified as two clusters: affected and non-affected (depressed and non-depressed). Affected rats showed depressive- and anxiety-like behaviors, decreased locomotor activity, and increased pain threshold. However, non-affected rats were similar to controls. In addition, there was a downregulation of BDNF and upregulation of GSK3-β in affected rats. Spearman correlation analysis also showed a relationship between BDNF and GSK3-β expression levels with individual differences. In conclusion, the present study showed that BDNF and GSK3-β may be involved in individual differences in CUMS rats.

Therapeutic Effects Of Combined and Chronic Treatment of Tat-GluA23y and D-Serine on Cognitive Dysfunction in Postmenopausal Rats

BACKGROUND

The incidence of Alzheimer's disease (AD) in female gender compared with male has been addressed as a health concern, particularly in menopausal age. We here hypothesized that co-administration of NMDARs agonist (D-serine) and AMPARs endocytosis inhibitor (Tat-GluA23y) might be a potential target for alleviating memory impairment in sporadic Alzheimer model of rats.

METHODS

Forty-eight female Wistar rats weighing 200-220 randomly divided into six groups. One month later, ovariectomized rats underwent stereotaxic surgery and were cannulated into the brain lateral ventricles. Streptozotocin was injected (3 mg/kg), then animals received the related treatments until the day 51, which experienced acquisition of spatial memory in Morris Water Maze test. Finally, the level of phosphorylated cAMP response element binding protein (CREB) in the hippocampus was measured by Western blotting.

RESULTS

Co-administration of D-serine and GluA23y significantly enhanced the acquisition and retrieval of impaired spatial memory in ovariectomized rats with AD (p < .001). Compared to Glu-A 23, D-serine caused more improvement in the mentioned parameters above, however, these values for both groups were still significantly different from the control group (P < .05).

CONCLUSION

Simultaneous treatment with D-serine and GluA23y synergistically improved STZ induced spatial memory impairment in OVX rat, probably partly via increase in phosphorylated CREB protein.

The association between levels of brain-derived neurotrophic factor and comorbid depression in patients with cardiovascular disease: The Framingham Heart Study

AIM

The current study aims to investigate the association of serum brain-derived neurotrophic factor (BDNF) levels with symptoms of depression in adults with and without prevalent cardiovascular disease (CVD), an often burdensome comorbidity.

METHODS

This cross-sectional study included participants from FHS (Framingham Heart Study) who had available serum BDNF levels. Depressive symptoms were assessed using the Center for Epidemiological Studies-Depression Scale (CES-D) with a score ≥16 indicating mild to moderate and ≥21 severe depression. Participants taking antidepressant medications were excluded from the study.

RESULTS

Altogether 3716 FHS participants were included in the final analysis (mean age, 64.3 ± 11.5 years; 55% women). After adjusting for potential confounders, greater BDNF levels were associated with reduced severe depression risk (odds ratio [OR], 0.78 [95% CI, 0.64-0.96]; P = 0.016). Among participants with CVD, greater BDNF levels were related to lower risk of depressive symptoms (CES-D ≥ 16 OR, 0.63 [95% CI, 0.45-0.89], P = 0.008; CES-D ≥ 21 OR, 0.49 [95% CI, 0.31-0.76], P = 0.002). The inverse relationship between BDNF and depressive symptom risk was present in women with CVD (CES-D ≥ 16 OR, 0.63 [95% CI, 0.40-0.99], P = 0.047; CES-D ≥ 21 OR, 0.38 [95% CI, 0.21-0.70], P = 0.002) but not in men.

CONCLUSION

Lower serum BDNF levels are associated with a higher risk of depressive symptoms in CVD, particularly among women. These findings implicate BDNF in the complex biological mechanisms that underlie prior associations observed between CVD and depression. To reduce the burden of depression in the large proportion of midlife and older adults with CVD, a better understanding of how BDNF may modify these pathways is merited.

Exploring environmental exposomes and the gut-brain nexus: Unveiling the impact of pesticide exposure

This review delves into the escalating concern of environmental pollutants and their profound impact on human health in the context of the modern surge in global diseases. The utilisation of chemicals in food production, which results in residues in food, has emerged as a major concern nowadays. By exploring the intricate relationship between environmental pollutants and gut microbiota, the study reveals a dynamic bidirectional interplay, as modifying microbiota profile influences metabolic pathways and subsequent brain functions. This review will first provide an overview of potential exposomes and their effect to gut health. This paper is then emphasis the connection of gut brain function by analysing microbiome markers with neurotoxicity responses. We then take pesticide as example of exposome to elucidate their influence to biomarkers biosynthesis pathways and subsequent brain functions. The interconnection between neuroendocrine and neuromodulators elements and the gut-brain axis emerges as a pivotal factor in regulating mental health and brain development. Thus, manipulation of gut microbiota function at the onset of stress may offer a potential avenue for the prevention and treatment for mental disorder and other neurodegenerative illness.

Sex and Time: Important Variables for Understanding the Impact of Constant Darkness on Behavior, Brain, and Physiology

The circadian clock can coordinate, regulate and predict physiology and behavior in response to the standard light-dark (LD: 12 h light and 12 h dark) cycle. If we alter the LD cycle by exposing mice to constant darkness (DD: 00 h light and 24 h dark), it can perturb behavior, the brain, and associated physiological parameters. The length of DD exposure and the sex of experimental animals are crucial variables that could alter the impact of DD on the brain, behavior, and physiology, which have not yet been explored. We exposed mice to DD for three and five weeks and studied their impact on (1) behavior, (2) hormones, (3) the prefrontal cortex, and (4) metabolites in male and female mice. We also studied the effect of three weeks of standard light-dark cycle restoration after five weeks of DD on the parameters mentioned above. We found that DD exposure was associated with anxiety-like behavior, increased corticosterone and pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β), downregulated neurotrophins (BDNF and NGF), and altered metabolites profile in a duration of DD exposure and sex-dependent manner. Females showed a more robust adaptation than males under DD exposure. Three weeks of restoration was adequate to establish homeostasis in both sexes. To the best of our knowledge, this study is the first of its kind to look at how DD exposure impacts physiology and behavior as a function of sex- and time. These findings would have translational value and may help in establishing sex-specific interventions for addressing DD-related psychological issues.

The Role of Brain-Derived Neurotrophic Factor in Immune-Related Diseases: A Narrative Review

Brain-derived neurotrophic factor (BDNF) is a neurotrophin regulating synaptic plasticity, neuronal excitability, and nociception. It seems to be one of the key molecules in interactions between the central nervous system and immune-related diseases, i.e., diseases with an inflammatory background of unknown etiology, such as inflammatory bowel diseases or rheumatoid arthritis. Studies show that BDNF levels might change in the tissues and serum of patients during the course of these conditions, e.g., affecting cell survival and modulating pain severity and signaling pathways involving different neurotransmitters. Immune-related conditions often feature psychiatric comorbidities, such as sleep disorders (e.g., insomnia) and symptoms of depression/anxiety; BDNF may be related as well to them as it seems to exert an influence on sleep structure; studies also show that patients with psychiatric disorders have decreased BDNF levels, which increase after treatment. BDNF also has a vital role in nociception, particularly in chronic pain, hyperalgesia, and allodynia, participating in the formation of central hypersensitization. In this review, we summarize the current knowledge on BDNF's function in immune-related diseases, sleep, and pain. We also discuss how BDNF is affected by treatment and what consequences these changes might have beyond the nervous system.

Perinatal transmission of a probiotic Bifidobacterium strain protects against early life stress-induced mood and gastrointestinal motility disorders

Early life stress can considerably interfere in gut microbiome formation and nervous system development. Specific probiotic strains have been proved to exert anti-stress effects by modulating the gut-brain axis. However, little is known about whether probiotic treatment during pregnancy can protect the offspring from early life stress. In this study, Bifidobacterium breve CCFM1025, previously proven to exert microbial and neurobiological regulation effects, was given to pregnant mice. The offspring's gut and brain functions were evaluated when challenged with maternal separation. Intriguingly, treatment with probiotics during pregnancy protected the offspring from maternal separation-induced neurobiological and gastrointestinal disorders such as depression-like behaviour and delayed defecation. Quantification of CCFM1025 was performed, and perinatal transmission of CCFM1025 was further validated, which also explained the reason for increased levels of colonic 5-hydroxytryptamine and caecal short-chain fatty acids in the offspring. Our findings indicated that the effects of probiotics can be perinatally transmitted through gut microbes and that probiotic treatment during pregnancy may have great potential in managing health risks in early life.

Evaluation of the Antidepressant-like Effect of Chronic Administration of Nigella Fixed Oil Versus Fluoxetine in Rats

BACKGROUND

Depression is a group of syndromes characterized by notable and persistent mood disorders, and is one of the most prevalent psychiatric disorders, while the existing treatments have an altered risk-benefit balance. The therapeutic properties of Nigella have been confirmed, suggesting the reliance on phytotherapy.

OBJECTIVES

The objective of the present paper is to investigate the antidepressive-like effect of Nigella sativa on rats exposed to the Unpredictable Chronic Mild Stress procedure.

METHODS

Wistar rats were used to investigate the antidepressive-like effect. The stress procedure used in this study combined many stressful conditions. After 6 weeks of treatment, behavioral test (forced swim test) was conducted, and histological changes of the hippocampus were examined.

RESULTS

Treatment by nigella and fluoxetine significantly reduced the immobilization time. Histopathological analysis showed that control treatments result in more loosely arranged cells, significant apoptotic neurons characterized by an irregular appearance, and pyknotic hyperchromatic.

CONCLUSION

A preservation of the thickness of the pyramid layer was also observed in the groups treated with nigella and fluoxetine, suggesting that nigella could be used as a treatment or an adjuvant preventing depressive-like disorders.

Psychedelics and Other Psychoplastogens for Treating Mental Illness

Psychedelics have inspired new hope for treating brain disorders, as they seem to be unlike any treatments currently available. Not only do they produce sustained therapeutic effects following a single administration, they also appear to have broad therapeutic potential, demonstrating efficacy for treating depression, post-traumatic stress disorder (PTSD), anxiety disorders, substance abuse disorder, and alcohol use disorder, among others. Psychedelics belong to a more general class of compounds known as psychoplastogens, which robustly promote structural and functional neural plasticity in key circuits relevant to brain health. Here we discuss the importance of structural plasticity in the treatment of neuropsychiatric diseases, as well as the evidence demonstrating that psychedelics are among the most effective chemical modulators of neural plasticity studied to date. Furthermore, we provide a theoretical framework with the potential to explain why psychedelic compounds produce long-lasting therapeutic effects across a wide range of brain disorders. Despite their promise as broadly efficacious neurotherapeutics, there are several issues associated with psychedelic-based medicines that drastically limit their clinical scalability. We discuss these challenges and how they might be overcome through the development of non-hallucinogenic psychoplastogens. The clinical use of psychedelics and other psychoplastogenic compounds marks a paradigm shift in neuropsychiatry toward therapeutic approaches relying on the selective modulation of neural circuits with small molecule drugs. Psychoplastogen research brings us one step closer to actually curing mental illness by rectifying the underlying pathophysiology of disorders like depression, moving beyond simply treating disease symptoms. However, determining how to most effectively deploy psychoplastogenic medicines at scale will be an important consideration as the field moves forward.

Interleukin-1 receptor on hippocampal neurons drives social withdrawal and cognitive deficits after chronic social stress

Chronic stress contributes to the development of psychiatric disorders including anxiety and depression. Several inflammatory-related effects of stress are associated with increased interleukin-1 (IL-1) signaling within the central nervous system and are mediated by IL-1 receptor 1 (IL-1R1) on several distinct cell types. Neuronal IL-1R1 is prominently expressed on the neurons of the dentate gyrus, but its role in mediating behavioral responses to stress is unknown. We hypothesize that IL-1 acts on this subset of hippocampal neurons to influence cognitive and mood alterations with stress. Here, mice subjected to psychosocial stress showed reduced social interaction and impaired working memory, and these deficits were prevented by global IL-1R1 knockout. Stress-induced monocyte trafficking to the brain was also blocked by IL-1R1 knockout. Selective deletion of IL-1R1 in glutamatergic neurons (nIL-1R1^-/-) abrogated the stress-induced deficits in social interaction and working memory. In addition, viral-mediated selective IL-1R1 deletion in hippocampal neurons confirmed that IL-1 receptor in the hippocampus was critical for stress-induced behavioral deficits. Furthermore, selective restoration of IL-1R1 on glutamatergic neurons was sufficient to reestablish the impairments of social interaction and working memory after stress. RNA-sequencing of the hippocampus revealed that stress increased several canonical pathways (TREM1, NF-κB, complement, IL-6 signaling) and upstream regulators (INFγ, IL-1β, NF-κB, MYD88) associated with inflammation. The inductions of TREM1 signaling, complement, and leukocyte extravasation with stress were reversed by nIL-1R1^-/-. Collectively, stress-dependent IL-1R1 signaling in hippocampal neurons represents a novel mechanism by which inflammation is perpetuated and social interactivity and working memory are modulated.

Brain-derived neurotrophic factor attenuates cognitive impairment and motor deficits in a mouse model of Parkinson's disease

BACKGROUND

Parkinson's disease (PD) is one of the most common neurodegenerative disorders that seriously impair the life quality and survival of patients. Herein, we aim to investigate the neuroprotective roles of brain-derived neurotrophic factor (BDNF) in PD mice and reveal the underlying mechanisms. BDNF overexpression was achieved via the injection of adeno-associated viruses (AAV) with BDNF gene.

METHODS

PD mouse model was established by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment. Tests of rotarod, pole, open field, and novel object recognition were conducted to evaluate the motor and cognitive functions of treated mice.

RESULTS

Mitochondrial impairment, mitochondrial respiratory chain enzymes, and tyrosine hydroxylase (TH)-positive dopaminergic neurons were detected to uncover the molecular mechanism. BDNF overexpression attenuated motor deficits and cognitive impairment in MPTP-induced PD mice. Mechanistically, BDNF mitigated mitochondrial impairment increased the activity of respiratory chain Complex I and Ⅱ+III, and finally alleviated TH-positive dopaminergic neuron loss in MPTP-induced PD mice.

CONCLUSION

This study highlights the potential of BDNF as a therapeutic candidate for the treatment of mitochondrial impairment-associated neurodegenerative diseases.

The Dual Dose-Dependent Effects of Corticosterone on Hippocampal Cell Apoptosis After Traumatic Brain Injury Depend on the Activation Ratio of Mineralocorticoid Receptors to Glucocorticoid Receptors

In our recent studies, we reported that mineralocorticoid receptor (MR) had the opposite effects of glucocorticoid receptor (GR) on neural cell survival after traumatic brain injury (TBI). However, whether short-term use of high-dose natural glucocorticoids, which are mixed agonists of both MR and GR, leads to neurotoxic effects by inducing excessive GR activation is unclear, as is the threshold GR activation level and the possible signaling pathways remain unclear. In this study, we examined the dual dose-dependent effects of corticosterone (CORT) on spatial memory, hippocampal cell survival and receptor-mediated downstream signaling pathways after TBI. We found that different doses of CORT exhibited dual effects on hippocampal cell survival and rat spatial memory. Low doses of CORT (0.3 and 3 mg/kg) significantly increased MR activation, upregulated Akt/CREB/Bad phosphorylation and Bcl-2 concentration, reduced the number of apoptotic neural cells, and subsequently improved rat spatial memory. In contrast, a high dose of CORT (30 mg/kg) exerted the opposite effects by overactivating GR, upregulating P53/Bax levels, and inhibiting Erk/CREB activity. The results suggest that the neuroprotective and neurotoxic effects of endogenous GC depend on a threshold level and that a higher dose of GC, even for short-term use, should be avoided after TBI.

Combining Growth Factor and Stem Cell Therapy for Stroke Rehabilitation, A Review

Stroke is a serious, life-threatening condition demanding vigorous search for new therapies. Recent research has focused on stem cell-based therapies as a viable choice following ischemic stroke, based on studies displaying that stem cells transplanted to the brain not only survive but also cause functional recovery. Growth factors defined as polypeptides that regulate the growth and differentiation of many cell types. Many studies have demonstrated that combined use of growth factors may increase results by the stimulation of endogenous neurogenesis, anti-inflammatory, neuroprotection properties, and enhancement of stem cell survival rates and so may be more effective than a single stem cell therapy. This paper reviews and discusses the most promising new stroke recovery research, including combination treatment.

Asparagus cochinchinensis extract ameliorates menopausal depression in ovariectomized rats under chronic unpredictable mild stress

BACKGROUND

Depression is a serious and common psychiatric disorder generally affecting more women than men. A woman's risk of developing depression increases steadily with age, and higher incidence is associated with the onset of menopause. Here we evaluated the antidepressant properties of Asparagus cochinchinensis (AC) extract and investigated its underlying mechanisms in a rat menopausal depression model.

METHODS

To model this menopausal depression, we induced a menopause-like state in rats via ovariectomy and exposed them to chronic unpredictable mild stress (CUMS) for 6 weeks, which promotes the development of depression-like symptoms. During the final 4 weeks of CUMS, rats were treated with either AC extract (1000 or 2000 mg/kg, PO), which has been reported to provide antidepressant effects, or with the tricyclic antidepressant imipramine (10 mg/kg, IP).

RESULTS

We report that CUMS promotes depression-like behavior and significantly increases serum corticosterone and inflammatory cytokine levels in the serum of ovariectomized (OVX) rats. We also found that CUMS decreases the expression of brain-derived neurotrophic factor (BDNF) and its primary receptor, tropomyosin receptor kinase B (TrkB), in OVX rats, and treatment with AC extract rescues both BDNF and TrkB expression levels.

CONCLUSION

These results suggest that AC extract exerts antidepressant effects, possibly via modulation of the BDNF-TrkB pathway, in a rat model of menopausal depression.

Transcranial Magnetic Stimulation-Induced Plasticity Mechanisms: TMS-Related Gene Expression and Morphology Changes in a Human Neuron-Like Cell Model

Transcranial Magnetic Stimulation (TMS) is a form of non-invasive brain stimulation, used to alter cortical excitability both in research and clinical applications. The intermittent and continuous Theta Burst Stimulation (iTBS and cTBS) protocols have been shown to induce opposite after-effects on human cortex excitability. Animal studies have implicated synaptic plasticity mechanisms long-term potentiation (LTP, for iTBS) and depression (LTD, for cTBS). However, the neural basis of TMS effects has not yet been studied in human neuronal cells, in particular at the level of gene expression and synaptogenesis. To investigate responses to TBS in living human neurons, we differentiated human SH-SY5Y cells toward a mature neural phenotype, and stimulated them with iTBS, cTBS, or sham (placebo) TBS. Changes in (a) mRNA expression of a set of target genes (previously associated with synaptic plasticity), and (b) morphological parameters of neurite outgrowth following TBS were quantified. We found no general effects of stimulation condition or time on gene expression, though we did observe a significantly enhanced expression of plasticity genes NTRK2 and MAPK9 24 h after iTBS as compared to sham TBS. This specific effect provides unique support for the widely assumed plasticity mechanisms underlying iTBS effects on human cortex excitability. In addition to this protocol-specific increase in plasticity gene expression 24 h after iTBS stimulation, we establish the feasibility of stimulating living human neuron with TBS, and the importance of moving to more complex human in vitro models to understand the underlying plasticity mechanisms of TBS stimulation.

Anti-Apoptotic Effects of Carotenoids in Neurodegeneration

Apoptosis, programmed cell death type I, is a critical part of neurodegeneration in cerebral ischemia, Parkinson’s, and Alzheimer’s disease. Apoptosis begins with activation of pro-death proteins Bax and Bak, release of cytochrome c and activation of caspases, loss of membrane integrity of intracellular organelles, and ultimately cell death. Approaches that block apoptotic pathways may prevent or delay neurodegenerative processes. Carotenoids are a group of pigments found in fruits, vegetables, and seaweeds that possess antioxidant properties. Over the last several decades, an increasing number of studies have demonstrated a protective role of carotenoids in neurodegenerative disease. In this review, we describe functions of commonly consumed carotenoids including lycopene, β-carotene, lutein, astaxanthin, and fucoxanthin and their roles in neurodegenerative disease models. We also discuss the underlying cellular mechanisms of carotenoid-mediated neuroprotection, including their antioxidant properties, role as signaling molecules, and as gene regulators that alleviate apoptosis-associated brain cell death.

Neuroprotective and neuro-survival properties of safinamide against methamphetamine-induced neurodegeneration: Hypothetic possible role of BDNF/TrkB/PGC-1α signaling pathway and mitochondrial uncoupling protein -2(UCP-2)

Methamphetamine is a behavioral psychostimulant that has a high potential for misuse and induction of neurotoxicity. Safinamide is a novel inhibitor of monoamine oxidase B (MAOB) with neuroprotective properties. Methamphetamine abuse causes dysfunction in the respiratory chain of the mitochondria, but the specific signaling mechanism and role of the uncoupling protein-2(UCP-2) remain unclear. As we know, some indirect evidence indicates that neurodegeneration can be caused by inhibition of the brain-derived neurotrophic factor (BDNF) receptor, TrkB and its downstream signaling pathway, such as the PGC-1α protein. Neuroprotective strategies and approaches to the management, treatment or prevention of methamphetamine-induced neurodegeneration by modulating BDNF / TrkB / PGC-1α-UCP-2 can be considered as novel therapeutic approaches to these psychostimulant neurochemical and neurobehavioral approaches. Previous studies have shown that safinamide, a monoamine oxidase-B (MAOB) inhibitor, can function as a neuroprotective agent and inhibit the neurodegenerative process especially in Parkinson's disease but its impact on other neurodegenerative processes and drug-induced neurotoxicity remain unclear. Although there is some evidence that BDNF / TrkB / PGC-1α-UCP-2 signaling pathway and mitochondrial UCP-2 mediated safinamide induced neuroprotection but it's exact and precise mechanism of action and neuroprotective effects in neurodegenerative disorder and the protective properties against methamphetamine induced neurodegeneration and the role of BDNF / TrkB / PGC-1α signaling pathway and role of mitochondrial UCP-2 in this process have not yet been clarified. Therefore, in subjects addicted to methamphetamine, we hypothesized that safinamide will provide neuroprotection against methamphetamine-prompted neurodegeneration, and it appears that BDNF / TrkB / PGC-1α signaling pathway and mitochondrial UCP-2 are likely to play a critical role.

Towards a psychobiotic therapy for depression: Bifidobacterium breve CCFM1025 reverses chronic stress-induced depressive symptoms and gut microbial abnormalities in mice

BACKGROUND

Accumulating evidence points to an association between gut microbial abnormalities and depression disorder. The microbiota-gut-brain axis is an emerging target for treating depression using nutritional strategies, considering the numerous limitations of current pharmacological approaches. Here we studied the effect and probable mechanisms of psychobiotic treatment on depression.

METHODS

Chronically stressed C57BL/6J male mice were administered viable Bifidobacterium breve CCFM1025 for 5 weeks prior to behavioral testing. Brain neurological alterations, serum corticosterone, cytokines levels, fecal microbial composition, and short-chain fatty acid (SCFA) content were measured. In addition, the effect of SCFA on 5-hydroxytryptophan (5-HTP) biosynthesis was investigated in an in vitro model of enterochromaffin cells (RIN14B).

RESULTS

CCFM1025 treatment significantly reduced depression- and anxiety-like behaviors. The hyperactive hypothalamic-pituitary-adrenal response, as well as inflammation, were also alleviated, possibly via regulating the expression of glucocorticoid receptors (Nr3c1). Moreover, CCFM1025 also down-regulated the pCREB-c-Fos pathway but increased the expression of brain-derived neurotrophic factor (BDNF). Meanwhile, chronic stress-induced gut microbial abnormalities were restored, accompanied by increased SCFA and 5-HTP levels. The intestinal 5-HTP biosynthesis positively correlated with fecal SCFA and Bifidobacterium breve levels.

CONCLUSIONS

In summary, Bifidobacterium breve CCFM1025 showed considerable antidepressant-like and microbiota-regulating effects, which opens avenues for novel therapeutic strategies towards treating depression.

Schisandra Extract and Ascorbic Acid Synergistically Enhance Cognition in Mice Through Modulation of Mitochondrial Respiration

Cognitive decline is observed in aging and neurodegenerative diseases, including Alzheimer’s disease (AD) and dementia. Intracellular energy produced via mitochondrial respiration is used in the regulation of synaptic plasticity and structure, including dendritic spine length and density, as well as for the release of neurotrophic factors involved in learning and memory. To date, a few synthetic agents for improving mitochondrial function have been developed for overcoming cognitive impairment. However, no natural compounds that modulate synaptic plasticity by directly targeting mitochondria have been developed. Here, we demonstrate that a mixture of Schisandra chinensis extract (SCE) and ascorbic acid (AA) improved cognitive function and induced synaptic plasticity-regulating proteins by enhancing mitochondrial respiration. Treatment of embryonic mouse hippocampal mHippoE-14 cells with a 4:1 mixture of SCE and AA increased basal oxygen consumption rate. We found that mice injected with the SCE-AA mixture showed enhanced learning and memory and recognition ability. We further observed that injection of the SCE-AA mixture in mice significantly increased expression of postsynaptic density protein 95 (PSD95), an increase that was correlated with enhanced brain-derived neurotrophic factor (BDNF) expression. These results demonstrate that a mixture of SCE and AA improves mitochondrial function and memory, suggesting that this natural compound mixture could be used to alleviate AD and aging-associated memory decline.

Memory Impairment Induced by Chronic Psychosocial Stress Is Prevented by L-Carnitine

Introduction

Psychosocial stress (STS) negatively influences memory. This might be associated to oxidative stress-induced progressive destruction of numerous brain structures and functions. L-carnitine (L-CAR) is a widely used antioxidant compound that is endogenously made in mammalian species. The current study investigated the effect of L-CAR on STS-induced memory impairment in the rat hippocampus.

Methods

The STS was induced using intruder model, where two rats were randomly switched from each one cage to another, once/day for 6 weeks. Concurrently, L-CAR (300mg/kg/day) was intraperitoneally administered for 6 weeks. After that, radial arm water maze (RAWM) was used to assess spatial learning memory in rats. Hippocampal biomarkers of oxidative stress, including thiobarbituric acid reactive substance (TBARs), oxidized glutathione (GSSG), reduced glutathione (GSH), glutathione peroxidase (GPx), catalase, and superoxide dismutase (SOD), and Brain-derived neurotrophic factor (BDNF) were examined.

Results

The results showed impairment of short-term memory (P < 0.05) during STS, whereas L-CAR treatment protected against this effect. Furthermore, while no change was observed in GSH, GSSG, GPx, catalase, and SOD, L-carnitine normalized STS-induced reduction in the hippocampal BDNF levels and increase in TBARS levels.

Discussion

Chronic psychosocial stress-induced memory impairment was prevented via L-CAR administration, which could have been achieved via normalizing changes in lipid peroxidation (TBARs) and BDNF levels in the hippocampus.

Marine omega-3 (n-3) phospholipids: A comprehensive review of their properties, sources, bioavailability, and relation to brain health

For several decades, there has been considerable interest in marine-derived long chain n-3 fatty acids (n-3 LCPUFAs) due to their outstanding health benefits. n-3 LCPUFAs can be found in nature either in triglycerides (TAGs) or in phospholipid (PL) form. From brain health point of view, PL n-3 is more bioavailable and potent compared to n-3 in TAG form, as only PL n-3 is able to cross the blood-brain barrier and can be involved in brain biochemical reactions. However, PL n-3 has been ignored in the fish oil industry and frequently removed as an impurity during degumming processes. As a result, PL products derived from marine sources are very limited compared to TAG products. Commercially, PLs are being used in pharmaceutical industries as drug carriers, in food manufacturing as emulsifiers and in cosmetic industries as skin care agents, but most of the PLs used in these applications are produced from vegetable sources that contain less (without EPA, DPA, and DHA) or sometimes no n-3 LCPUFAs. This review provides a comprehensive account of the properties, structures, and major sources of marine PLs, and provides focussed discussion of their relationship to brain health. Epidemiological, laboratory, and clinical studies on n-3 LCPUFAs enriched PLs using different model systems in relation to brain and mental health that have been published over the past few years are discussed in detail.