Synapse impairment associated with enhanced apoptosis in post-traumatic stress disorder

HGF secreted by hUC-MSCs mitigates neuronal apoptosis to repair the injured spinal cord via phosphorylation of Akt/FoxO3a pathway

Spinal cord injury (SCI) can cause severe and permanent neurological damage, and neuronal apoptosis could inhibit functional recovery of damaged spinal cord greatly. Human umbilical cord mesenchymal stem cells (hUC-MSCs) have great potential to repair SCI because of a series of advantages, including inhibition of neuronal apoptosis and multiple differentiation. The former may play an important role. However, the detailed regulatory mechanism associated with the inhibition of neuronal apoptosis after hUC-MSCs administration has not been elucidated. In this study, proteomics analysis of precious human cerebrospinal fluid (CSF) samples collected from SCI subjects receiving hUC-MSCs delivery indicated that hepatocyte growth factor (HGF) is largely involved in SCI repair. Furthermore, overexpression of HGF derived from hUC-MSCs could decrease reactive oxygen species to prevent neuron apoptosis to the maximum, and thus lead to significant recovery of spinal cord dysfunction. Moreover, HGF could promote phosphorylation of Akt/FoxO3a pathway to decrease reactive oxygen species to reduce neuron apoptosis. For the first time, our research revealed that HGF secreted by hUC-MSCs inhibits neuron apoptosis by phosphorylation of Akt/FoxO3a to repair SCI. This study provides important clues associated with drug selection for the effective treatment of SCI in humans.

"NO" Time in Fear Response: Possible Implication of Nitric-Oxide-Related Mechanisms in PTSD

Post-traumatic stress disorder (PTSD) is a psychiatric condition characterized by persistent fear responses and altered neurotransmitter functioning due to traumatic experiences. Stress predominantly affects glutamate, a neurotransmitter crucial for synaptic plasticity and memory formation. Activation of the N-Methyl-D-Aspartate glutamate receptors (NMDAR) can trigger the formation of a complex comprising postsynaptic density protein-95 (PSD95), the neuronal nitric oxide synthase (nNOS), and its adaptor protein (NOS1AP). This complex is pivotal in activating nNOS and nitric oxide (NO) production, which, in turn, activates downstream pathways that modulate neuronal signaling, including synaptic plasticity/transmission, inflammation, and cell death. The involvement of nNOS and NOS1AP in the susceptibility of PTSD and its comorbidities has been widely shown. Therefore, understanding the interplay between stress, fear, and NO is essential for comprehending the maintenance and progression of PTSD, since NO is involved in fear acquisition and extinction processes. Moreover, NO induces post-translational modifications (PTMs), including S-nitrosylation and nitration, which alter protein function and structure for intracellular signaling. Although evidence suggests that NO influences synaptic plasticity and memory processing, the specific role of PTMs in the pathophysiology of PTSD remains unclear. This review highlights pathways modulated by NO that could be relevant to stress and PTSD.

Stress-related cellular pathophysiology as a crosstalk risk factor for neurocognitive and psychiatric disorders

In this narrative review, we examine biological processes linking psychological stress and cognition, with a focus on how psychological stress can activate multiple neurobiological mechanisms that drive cognitive decline and behavioral change. First, we describe the general neurobiology of the stress response to define neurocognitive stress reactivity. Second, we review aspects of epigenetic regulation, synaptic transmission, sex hormones, photoperiodic plasticity, and psychoneuroimmunological processes that can contribute to cognitive decline and neuropsychiatric conditions. Third, we explain mechanistic processes linking the stress response and neuropathology. Fourth, we discuss molecular nuances such as an interplay between kinases and proteins, as well as differential role of sex hormones, that can increase vulnerability to cognitive and emotional dysregulation following stress. Finally, we explicate several testable hypotheses for stress, neurocognitive, and neuropsychiatric research. Together, this work highlights how stress processes alter neurophysiology on multiple levels to increase individuals' risk for neurocognitive and psychiatric disorders, and points toward novel therapeutic targets for mitigating these effects. The resulting models can thus advance dementia and mental health research, and translational neuroscience, with an eye toward clinical application in cognitive and behavioral neurology, and psychiatry.

Effects and mechanisms of salidroside on the behavior of SPS-induced PTSD rats

Post-traumatic stress disorder (PTSD) is a complex mental disorder, closely associated with stress and traumatic events. Salidroside (Sal) has been reported to possess neuroprotective effects. However, the behavioral effects and mechanisms of Sal on PTSD remain unknown. In this study, we utilized a rat model of PTSD induced by single prolonged stress (SPS) and administered Sal intraperitoneally (25, 50, 75 mg/kg/d) for 14 days. We then examined the behavioral effects and underlying mechanisms of Sal on SPS-induced PTSD rats. Our findings demonstrated that Sal alleviated anxiety-like behavior and spatial learning and memory impairment in SPS-induced PTSD rats. Furthermore, Sal treatment preserved the histomorphology of the hippocampal region. It was observed that Sal protected against hippocampal neuronal apoptosis in PTSD rats by reducing the number of TUNEL-positive cells and modulating apoptosis-related proteins (Bcl-2 and Bax). Additionally, Sal inhibited the activation of the NF-κB/iNOS/COX-2 signaling pathway in the hippocampus of PTSD rats, thereby suppressing the release of inflammatory factors (TNF-α and IL-1β) and the activation of microglia. Notably, Sal increased the expression of synapse-associated proteins PSD95 and Synapsin I in the hippocampus, while also enhancing dendritic density in the region. In conclusion, our results demonstrated that Sal could attenuate SPS-induced PTSD-like behaviors by inhibiting hippocampal neuronal apoptosis, enhancing hippocampal synaptic plasticity, and reducing neuroinflammatory responses. These findings may provide a foundation for the potential clinical application of Sal in the treatment of PTSD.

Effects and mechanisms of tanshinone IIA on PTSD-like symptoms

BACKGROUND

In recent years, Salvia miltiorrhiza and its active substances have remarkably progressed in treating central neurological disorders. Tanshinone IIA (TSA) is an active ingredient derived from the rhizome of Salvia miltiorrhiza that has been found to alleviate the symptoms of several psychiatric illnesses. Post-traumatic stress disorder (PTSD) is a mental disorder that results after experiencing a serious physical or psychological injury. The currently used drugs are not satisfactory for the treatment of PTSD. However, it has been reported that TSA can improve PTSD-like symptoms like learning and memory, cognitive disorder, and depression through multi-target regulation.

PURPOSE

This paper discusses the ameliorative effects of TSA on PTSD-like symptoms and the possible mechanisms of action in terms of inhibition of neuronal apoptosis, anti-neuroinflammation, and anti-oxidative stress. Based on the pathological changes and clinical observations of PTSD, we hope to provide some reference for the clinical transformation of Chinese medicine in treating PTSD.

METHODS

A large number of literatures on tanshinone in the treatment of neurological diseases and PTSD were retrieved from online electronic PubMed and Web of Science databases.

CONCLUSION

TSA is a widely studied natural active ingredient against mental illness. This review will contribute to the future development of TSA as a new clinical candidate drug for improving PTSD-like symptoms.

Identifying genetic loci that are associated with changes in gene expression in PTSD in a South African cohort

The molecular mechanisms underlying posttraumatic stress disorder (PTSD) are yet to be fully elucidated, especially in underrepresented population groups. Expression quantitative trait loci (eQTLs) are DNA sequence variants that influence gene expression, in a local (cis-) or distal (trans-) manner, and subsequently impact cellular, tissue, and system physiology. This study aims to identify genetic loci associated with gene expression changes in a South African PTSD cohort. Genome-wide genotype and RNA-sequencing data were obtained from 32 trauma-exposed controls and 35 PTSD cases of mixed-ancestry, as part of the SHARED ROOTS project. The first approach utilised 108 937 single-nucleotide polymorphisms (SNPs) (MAF > 10%) and 11 312 genes with Matrix eQTL to map potential eQTLs, while controlling for covariates as appropriate. The second analysis was focused on 5638 SNPs related to a previously calculated PTSD polygenic risk score for this cohort. SNP-gene pairs were considered eQTLs if they surpassed Bonferroni correction and had a false discovery rate <0.05. We did not identify eQTLs that significantly influenced gene expression in a PTSD-dependent manner. However, several known cis-eQTLs, independent of PTSD diagnosis, were observed. rs8521 (C > T) was associated with TAGLN and SIDT2 expression, and rs11085906 (C > T) was associated with ZNF333 expression. This exploratory study provides insight into the molecular mechanisms associated with PTSD in a non-European, admixed sample population. This study was limited by the cross-sectional design and insufficient statistical power. Overall, this study should encourage further multi-omics approaches towards investigating PTSD in diverse populations.

The Role of Gasotransmitter-Dependent Signaling Mechanisms in Apoptotic Cell Death in Cardiovascular, Rheumatic, Kidney, and Neurodegenerative Diseases and Mental Disorders

Cardiovascular, rheumatic, kidney, and neurodegenerative diseases and mental disorders are a common cause of deterioration in the quality of life up to severe disability and death worldwide. Many pathological conditions, including this group of diseases, are based on increased cell death through apoptosis. It is known that this process is associated with signaling pathways controlled by a group of gaseous signaling molecules called gasotransmitters. They are unique messengers that can control the process of apoptosis at different stages of its implementation. However, their role in the regulation of apoptotic signaling in these pathological conditions is often controversial and not completely clear. This review analyzes the role of nitric oxide (NO), carbon monoxide (CO), hydrogen sulfide (H₂S), and sulfur dioxide (SO₂) in apoptotic cell death in cardiovascular, rheumatic, kidney, and neurodegenerative diseases. The signaling processes involved in apoptosis in schizophrenia, bipolar, depressive, and anxiety disorders are also considered. The role of gasotransmitters in apoptosis in these diseases is largely determined by cell specificity and concentration. NO has the greatest dualism; scales are more prone to apoptosis. At the same time, CO, H₂S, and SO₂ are more involved in cytoprotective processes.

Nutraceutical Interventions for Post-Traumatic Stress Disorder in Animal Models: A Focus on the Hypothalamic–Pituitary–Adrenal Axis

Post-traumatic stress disorder (PTSD) occurs after exposure to traumatic events and is characterized by overwhelming fear and anxiety. Disturbances in the hypothalamic–pituitary–adrenal (HPA) axis are involved in the pathogenesis of mood disorders, including anxiety, PTSD, and major depressive disorders. Studies have demonstrated the relationship between the HPA axis response and stress vulnerability, indicating that the HPA axis regulates the immune system, fear memory, and neurotransmission. The selective serotonin reuptake inhibitors (SSRIs), sertraline and paroxetine, are the only drugs that have been approved by the United States Food and Drug Administration for the treatment of PTSD. However, SSRIs require long treatment times and are associated with lower response and remission rates; therefore, additional pharmacological interventions are required. Complementary and alternative medicine therapies ameliorate HPA axis disturbances through regulation of gut dysbiosis, insomnia, chronic stress, and depression. We have described the cellular and molecular mechanisms through which the HPA axis is involved in PTSD pathogenesis and have evaluated the potential of herbal medicines for PTSD treatment. Herbal medicines could comprise a good therapeutic strategy for HPA axis regulation and can simultaneously improve PTSD-related symptoms. Finally, herbal medicines may lead to novel biologically driven approaches for the treatment and prevention of PTSD.

Role of Stress-Related Dopamine Transmission in Building and Maintaining a Protective Cognitive Reserve

This short review presents the hypothesis that stress-dependent dopamine (DA) transmission contributes to developing and maintaining the brain network supporting a cognitive reserve. Research has shown that people with a greater cognitive reserve are better able to avoid symptoms of degenerative brain changes. The paper will review evidence that: (1) successful adaptation to stressors involves development and stabilization of effective but flexible coping strategies; (2) this process requires dynamic reorganization of functional networks in the adult brain; (3) DA transmission is amongst the principal mediators of this process; (4) age- and disease-dependent cognitive impairment is associated with dysfunctional connectivity both between and within these same networks as well as with reduced DA transmission.

Cerebrospinal fluid markers for synaptic function and Alzheimer type changes in late life depression

To explore markers for synaptic function and Alzheimer disease (AD) pathology in late life depression (LLD), predementia AD and normal controls (NC). A cross-sectional study to compare cerebrospinal fluid (CSF) levels of neurogranin (Ng), Beta-site amyloid-precursor-protein cleaving enzyme1 (BACE1), Ng/BACE1 ratio and Amyloid-β 42/40 ratio, phosphorylated-tau and total-tau in LLD with (LLD AD) or without (LLD NoAD) AD pathology, predementia AD and normal controls (NC). We included 145 participants (NC = 41; predementia AD = 66 and LLD = 38). LLD comprised LLD AD (n = 16), LLD NoAD (n = 19), LLD with non-AD typical changes (n = 3, excluded). LLD AD (pADJ < 0.05) and predementia AD (pADJ < 0.0001) showed significantly higher Ng than NC. BACE1 and Ng/BACE1 ratio were altered similarly. Compared to LLD NoAD, LLD AD showed significantly higher Ng (pADJ < 0.001), BACE1 (pADJ < 0.05) and Ng/BACE1 ratio (pADJ < 0.01). All groups had significantly lower Aβ 42/40 ratio than NC (predementia AD and LLD AD, p < 0.0001; LLD NoAD, p < 0.05). Both LLD groups performed similarly on tests of memory and executive function, but significantly poorer than NC. Synaptic function in LLD depended on AD pathology. LLD showed an association to Amyloid dysmetabolism. The LLD groups performed poorer cognitively than NC. LLD AD may be conceptualized as "predementia AD with depression".

A steroid-induced osteonecrosis model established using an organ-on-a-chip platform

Bone microvascular endothelial cells (BMECs) constitute the central part of the femoral head's intramural microenvironment network and have an essential role in the development of steroid-induced osteonecrosis of the femoral head. Recently, the rapid development of microfluidic technology has led to innovations in the fields of chemistry, medicine and life sciences. It is now possible to use microfluidics organ-on-a-chip techniques to assess osteonecrosis. In the present study, BMECs were cultured on a microfluidic organ-on-a-chip platform to explore the pathogenesis of femoral-head necrosis. The aim of the present study was to explore the effects of different interventions on BMECs and study the pathogenesis of steroid-induced osteonecrosis through a microfluidic organ-on-a-chip platform. Methods including SU-8 lithography were used to produce a microfluidic organ-on-a-chip and human umbilical vein endothelial cells (HUVECs) were used to test whether it was possible to culture cells on the chip. Subsequently, a set of methods were applied for the isolation, purification, culture and identification of BMECs. Hydroxyapatite (HA) was used for co-culture, dexamethasone was used at different concentrations as an intervention in the cells and icariin was used for protection. BMECs were isolated and cultured from the femoral head obtained following total hip arthroplasty and were then inoculated into the microfluidic organ-on-a-chip for further treatment. In part I of the experiment, HUVECs and BMECs both successfully survived on the chip and a comparison of the growth and morphology was performed. HA and BMECs were then co-cultured for comparison with the control group. The cell growth was observed by confocal microscopy after 24 h. In part II, the effects of different concentrations of glucocorticoid (0.4 or 0.6 mg/ml dexamethasone) and the protection of icariin were evaluated. The morphology of BMECs and the cleaved caspase-3/7 content were observed by immunofluorescence staining and confocal microscopy after 24 h. In the microfluidic organ-on-a-chip, the response of the cells was able to be accurately observed. In part I, at the same concentration of injected cells, BMECs exhibited improved viability compared with HUVECs (P<0.05). In addition, it was indicated that HA was not only able to promote the germination and growth of BMECs but also improve the survival of the cells (P<0.05). In part II, it was identified that dexamethasone was able to induce BMECs to produce cleaved caspase 3/7; the caspase 3/7 content was significantly higher than that in the blank control group (P<0.05) and a dose correlation was observed. Icariin was able to inhibit this process and protect the microvascular structure of BMECs. The content of cleaved caspase 3/7 in the icariin-protected group was significantly lower than that in the group without icariin (P<0.05). It was concluded that BMECs are more likely to survive than HUVECs and HA promoted the growth of BMECs on the microfluidic organ-on-a-chip platform. Glucocorticoid caused damage to BMECs through the production of cleaved caspase 3/7, which was observed through the microfluidic organ-on-a-chip platform, and icariin protected BMECs from damage.

Molecular Mechanism of the ATF6α/S1P/S2P Signaling Pathway in Hippocampal Neuronal Apoptosis in SPS Rats

Apoptosis of hippocampal neurons is one of the mechanisms of hippocampal atrophy in posttraumatic stress disorder (PTSD), and it is also an important cause of memory impairment in PTSD patients. Endoplasmic reticulum stress (ERS) mediated by activated transcription factor 6α (ATF6α)/site 1 protease (S1P)/S2P is involved in cell apoptosis, but it is not clear whether it is involved in hippocampal neuron apoptosis caused by PTSD. A PTSD rat model was constructed by the single prolonged stress (SPS) method. The study was divided into three parts. Experiment 1 included the control group, SPS 1 d group, SPS 7 d group, and SPS 14 d group. Experiment 2 included the control group, SPS 7 d group, SPS 7 d + AEBSF group, and control + AEBSF group. (4-(2-Aminoethyl)benzenesulfonyl fluoride hydrochloride (AEBSF) is an ATF6α pathway inhibitor). Experiment 3 included the control group, SPS 4 d group, SPS 4 d + AEBSF group, and control + AEBSF group. The protein and mRNA expression levels of ATF6α, glucose-regulated protein (GRP78), S1P, S2P, C/EBP homologous protein (CHOP), and caspase-12 in the hippocampus of PTSD rats were detected by immunohistochemistry, Western blotting and qRT-PCR. Apoptosis of hippocampal neurons was detected by TUNEL staining. In experiment 1, the protein and mRNA expression of ATF6α and GRP78 increased gradually in the SPS 1 d group and the SPS 7 d group but decreased in the SPS 14 d group (P < 0.01). In experiment 2, compared with that in the control group, the protein and mRNA expression of ATF6α, GRP78, S1P, S2P, CHOP, and caspase-12 and the apoptosis rate were significantly increased in the SPS 7 d group (P < 0.01). However, the protein and mRNA expression of ATF6α, GRP78, S1P, S2P, CHOP, and caspase-12 and the apoptosis rate were significantly decreased after AEBSF pretreatment (P < 0.01). In experiment 3, compared with that in the control group, the protein and mRNA expression of ATF6α, GRP78, S1P, S2P, CHOP, and caspase-12 and the apoptosis rate were increased in the SPS 14 d group (P < 0.05). However, the protein and mRNA expression of ATF6α, GRP78, S1P, S2P, CHOP, and caspase-12 and the apoptosis rate were decreased after AEBSF pretreatment (P < 0.05). SPS induced apoptosis of hippocampal neurons by activating ERS mediated by ATF6α, suggesting that ERS-induced apoptosis is involved in the occurrence of PTSD.