Neurotrophic basis to the pathogenesis of depression and phytotherapy

Ketogenic diet attenuates neuroinflammation and restores hippocampal neurogenesis to improve CUMS induced depression-like behavior in mice

The ketogenic diet (KD) has been proposed as a potential treatment for depression. However, the underlying mechanisms remain poorly understood. This study aimed to evaluate further the effects of KD on chronic unpredictable mild stress (CUMS)-induced depression in mice and investigate the underlying mechanisms. The results demonstrated that KD intervention significantly alleviated CUMS-induced depression-like behaviors, as evidenced by a decrease in immobility time in the forced swimming test and tail suspension test, an increase in distance traveled in the open field test, and a greater preference for sucrose in the sucrose preference test. KD alleviated neuroinflammation by reducing the levels of glial cell activation markers Iba-1 and GFAP, inhibiting the expression of inflammatory factors IL-1β, TNF-α, and COX-2, and suppressing the overactivation of the TLR4/MyD88/NF-κB signaling pathway. Furthermore, KD increased the number of DCX-, BrdU-, and PSD95-positive cells in the hippocampus and enhanced the BDNF/TrkB/CREB and Wnt/β-catenin signaling pathways, thereby promoting hippocampal neurogenesis. These findings suggested that KD alleviated CUMS-induced depression-like behaviors in mice by reducing neuroinflammation, enhancing neurotrophic signaling, and promoting hippocampal neurogenesis, thereby providing a mechanistic basis for its potential as a novel dietary antidepressant therapy.

Associations between biomarkers of inflammation and depressive symptoms-potential differences between diabetes types and symptom clusters of depression

Inflammation is a probable biological pathway underlying the relationship between diabetes and depression, but data on differences between diabetes types and symptom clusters of depression are scarce. Therefore, this cross-sectional study aimed to compare associations of a multimarker panel of biomarkers of inflammation with depressive symptoms and its symptom clusters between people with type 1 diabetes (T1D) and type 2 diabetes (T2D). This cross-sectional study combined data from five studies including 1260 participants (n = 706 T1D, n = 454 T2D). Depressive symptoms were assessed using the Center for Epidemiological Studies-Depression Scale (CES-D). Serum levels of 92 biomarkers of inflammation were quantified with proximity extension assay technology. After quality control, 76 biomarkers of inflammation remained for statistical analysis. Associations between biomarkers and depressive symptom scores and clusters (cognitive-affective, somatic, anhedonia) were estimated with multivariable linear regression models. Nine biomarkers were positively associated with depressive symptoms in the total sample (CCL11/eotaxin, CCL25, CDCP1, FGF-21, IL-8, IL-10RB, IL-18, MMP-10, TNFRSF9; all p < 0.05) without interaction by diabetes type. Associations differed for eight biomarkers (pinteraction < 0.05). TNFβ was inversely associated with depressive symptoms in T1D, whereas three biomarkers (GDNF, IL-18R1, LIF-R) were positively associated with depressive symptoms in T2D. For the remaining four biomarkers (CD6, CD244, FGF-5, IFNγ) associations were not significant in either subgroup. Biomarker associations were more pronounced with somatic and anhedonia than with cognitive-affective symptoms. These results indicate that different proinflammatory pathways may contribute to depression in T1D and T2D and that there may be a symptom specificity in the link between subclinical inflammation and depression.

Unraveling the Role of the Blood-Brain Barrier in the Pathophysiology of Depression: Recent Advances and Future Perspectives

Depression is a highly prevalent psychological disorder characterized by persistent dysphoria, psychomotor retardation, insomnia, anhedonia, suicidal ideation, and a remarkable decrease in overall well-being. Despite the prevalence of accessible antidepressant therapies, many individuals do not achieve substantial improvement. Understanding the multifactorial pathophysiology and the heterogeneous nature of the disorder could lead the way toward better outcomes. Recent findings have elucidated the substantial impact of compromised blood-brain barrier (BBB) integrity on the manifestation of depression. BBB functions as an indispensable defense mechanism, tightly overseeing the transport of molecules from the periphery to preserve the integrity of the brain parenchyma. The dysfunction of the BBB has been implicated in a multitude of neurological disorders, and its disruption and consequent brain alterations could potentially serve as important factors in the pathogenesis and progression of depression. In this review, we extensively examine the pathophysiological relevance of the BBB and delve into the specific modifications of its components that underlie the complexities of depression. A particular focus has been placed on examining the effects of peripheral inflammation on the BBB in depression and elucidating the intricate interactions between the gut, BBB, and brain. Furthermore, this review encompasses significant updates on the assessment of BBB integrity and permeability, providing a comprehensive overview of the topic. Finally, we outline the therapeutic relevance and strategies based on BBB in depression, including COVID-19-associated BBB disruption and neuropsychiatric implications. Understanding the comprehensive pathogenic cascade of depression is crucial for shaping the trajectory of future research endeavors.

CDNF Exerts Anxiolytic, Antidepressant-like, and Procognitive Effects and Modulates Serotonin Turnover and Neuroplasticity-Related Genes

Cerebral dopamine neurotrophic factor (CDNF) is an unconventional neurotrophic factor because it does not bind to a known specific receptor on the plasma membrane and functions primarily as an unfolded protein response (UPR) regulator in the endoplasmic reticulum. Data on the effects of CDNF on nonmotor behavior and monoamine metabolism are limited. Here, we performed the intracerebroventricular injection of a recombinant CDNF protein at doses of 3, 10, and 30 μg in C57BL/6 mice. No adverse effects of the CDNF injection on feed and water consumption or locomotor activity were observed for 3 days afterwards. Decreases in body weight and sleep duration were transient. CDNF-treated animals demonstrated improved performance on the operant learning task and a substantial decrease in anxiety and behavioral despair. CDNF in all the doses enhanced serotonin (5-HT) turnover in the murine frontal cortex, hippocampus, and midbrain. This alteration was accompanied by changes in the mRNA levels of the 5-HT1A and 5-HT7 receptors and in monoamine oxidase A mRNA and protein levels. We found that CDNF dramatically increased c-Fos mRNA levels in all investigated brain areas but elevated the phosphorylated-c-Fos level only in the midbrain. Similarly, enhanced CREB phosphorylation was found in the midbrain in experimental animals. Additionally, the upregulation of a spliced transcript of XBP1 (UPR regulator) was detected in the midbrain and frontal cortex. Thus, we can hypothesize that exogenous CDNF modulates the UPR pathway and overall neuronal activation and enhances 5-HT turnover, thereby affecting learning and emotion-related behavior.

The forensic aspects of suicide and neurotrophin factors: a research study

Introduction: Suicide represents a significant public health problem whose neurobiology is not yet fully understood. In many cases, suicidal behavior and psychiatric spectrum disorders are linked, in particular, to major depression. An emerging pathophysiological hypothesis underlines the role of neurotrophic factors, proteins involved in neurogenesis, in synaptic plasticity in response to stressors. Our research aims to evaluate the degree of expression of brain neurotrophic factor (BDNF) in brain areas involved in depressive disorder in suicidal subjects. Furthermore, we want to evaluate the expression of glial cell line-derived neurotrophic factor (GDNF) in suicidal subjects. Methods: We selected twenty confirmed cases of suicide among subjects with a clinical history of depressive pathology and possible psychopharmacological treatment, compared to ten controls of individuals who died of non-suicidal causes. For all selected cases and controls, immunohistochemical investigations were performed using a panel of antibodies against the BDNF and GDNF antigens on samples from the various brain areas. Results and discussion: The results show that BDNF was under-expressed in the cerebral parenchyma of subjects who died by suicide compared to controls, while there was an overexpression of GDNF in suicide victims, these data could be useful for a clinical application as potential markers for suicidal risk, to assess the severity of depression and development of specific pharmacological therapies for depression.

Comprehensive Review of Cyclamen: Development, Bioactive Properties, and Therapeutic Applications

Plants are being researched as potential sources of novel drugs, which has led to a recent acceleration in the discovery of new bioactive compounds. Research on tissue culture technology for the synthesis and processing of plant compounds has skyrocketed, surpassing all expectations. These plants can be bought either raw or as extracts, where some of the chemicals are extracted by mashing the plant in water, alcohol, or another solvent. The use of herbal medicine may open new chances for reducing the onset of infections and treating different diseases including cancer. A perennial plant that blooms in the winter, Cyclamen, is one of the most widely used potted flowers in many nations. Alkaloids, flavonoids, phenols, tannins, saponins, sterols, and glycosides are the main active components of Cyclamen. Analgesic, cytotoxic, antioxidant, antimicrobial, and anti-inflammatory properties have all been demonstrated as potential effects of various extracts of Cyclamen tubers. However, the use of this medicinal plant in official medicine will require further research in the areas of pharmacology. Furthermore, it is necessary to create standard operating procedures for a crude herbal medication. In this regard, this review aims to highlight the key characteristics of the Cyclamen plant, such as its various parts, species, stages of development, and geographic range; pinpoint its intriguing bioactivities, its antioxidant, anti-inflammatory, and its anti-cancerous effects; and ascertain its potential medicinal uses and the main future perspectives.

Potential antidepressant effects of Traditional Chinese botanical drug formula Chaihu-Shugan-San and its active ingredients

Background: Depression is a severe mental disorder that poses a significant threat to both the physical and mental wellbeing of individuals. Currently, there are various methods for treating depression, including traditional Chinese herbal formulations like Chaihu-Shugan-San (CSS), which have shown effective antidepressant effects in both clinical and animal research. Objective: This review aims to provide a comprehensive synthesis of evidence related to CSS, considering both preclinical and clinical studies, to uncover its potential multi-level, multi-pathway, and multi-target mechanisms for treating depression and identify its active ingredients. Methods: A thorough search was conducted in electronic databases, including PubMed, MEDLINE, Web of Science, Google Scholar, CNKI, and Wanfang, using keywords such as "Chaihu Shugan" and "depression" to retrieve relevant literature on CSS and its active ingredients. The review process adhered to the PRISMA guidelines. Results: This review consolidates the mechanisms underlying antidepressant effects of CSS and its active ingredients. It emphasizes its involvement in the regulation of monoaminergic neurotransmitter systems, synaptic plasticity, and the hypothalamic-pituitary-adrenal axis, among other aspects. Conclusion: CSS exerts a pivotal role in treating depression through various pathways, including the monoaminergic neurotransmitter system, the hypothalamic-pituitary-adrenal axis, synaptic plasticity, inflammation, brain-derived neurotrophic factor levels, and the brain-gut axis. This review facilitates a comprehensive understanding of the current state of CSS research, fostering an in-depth exploration of the etiological mechanisms of depression and the potential discovery of novel antidepressant drugs.

Terahertz Radiation Modulates Neuronal Morphology and Dynamics Properties

Terahertz radiation falls within the spectrum of hydrogen bonding, molecular rotation, and vibration, as well as van der Waals forces, indicating that many biological macromolecules exhibit a strong absorption and resonance in this frequency band. Research has shown that the terahertz radiation of specific frequencies and energies can mediate changes in cellular morphology and function by exciting nonlinear resonance effects in proteins. However, current studies have mainly focused on the cellular level and lack systematic studies on multiple levels. Moreover, the mechanism and law of interaction between terahertz radiation and neurons are still unclear. Therefore, this paper analyzes the mechanisms by which terahertz radiation modulates the nervous system, and it analyzes and discusses the methods by which terahertz radiation modulates neurons. In addition, this paper reviews the laws of terahertz radiation's influence on neuronal morphology and kinetic properties and discusses them in detail in terms of terahertz radiation frequency, energy, and time. In the future, the safety of the terahertz radiation system should be considered first to construct the safety criterion of terahertz modulation, and the spatial resolution of the terahertz radiation system should be improved. In addition, the systematic improvement of the laws and mechanisms of terahertz modulation of the nervous system on multiple levels is the key to applying terahertz waves to neuroscience. This paper can provide a platform for researchers to understand the mechanism of the terahertz-nervous system interaction, its current status, and future research directions.

Involvement of brain-derived neurotrophic factor signaling in the pathogenesis of stress-related brain diseases

Neurotrophins including brain-derived neurotrophic factor, BDNF, have critical roles in neuronal differentiation, cell survival, and synaptic function in the peripheral and central nervous system. It is well known that a variety of intracellular signaling stimulated by TrkB, a high-affinity receptor for BDNF, is involved in the physiological and pathological neuronal aspects via affecting cell viability, synaptic function, neurogenesis, and cognitive function. As expected, an alteration of the BDNF/TrkB system is suspected to be one of the molecular mechanisms underlying cognitive decline in cognitive diseases and mental disorders. Recent evidence has also highlighted a possible link between the alteration of TrkB signaling and chronic stress. Furthermore, it has been demonstrated that downregulation of the BDNF/TrkB system and chronic stress have a role in the pathogenesis of Alzheimer's disease (AD) and mental disorders. In this review, we introduce current evidence showing a close relationship between the BDNF/TrkB system and the development of cognition impairment in stress-related disorders, and the possible contribution of the upregulation of the BDNF/TrkB system in a therapeutic approach against these brain diseases.