Exosomal MicroRNAs: Biomarkers of moyamoya disease and involvement in vascular cytoskeleton reconstruction.

Moyamoya disease currently lacks a suitable method for early clinical screening.This study aimed to identify a simple and feasible clinical screening index by investigating microRNAs carried by peripheral blood exosomes. Experimental subjects participated in venous blood collection, and exosomes were isolated using Exquick-related technology. Sequencing was performed on the extracted exosomal ribonucleic acids (RNAs) to identify differential microRNAs. Verification of the results involved selecting relevant samples from the genetic database. The study successfully pinpointed a potential marker for early screening, hsa-miR-328-3p + hsa-miR-200c-3p carried by peripheral blood exosomes. Enrichment analysis of target genes revealed associations with intercellular junctions, impaired cytoskeletal regulation, and increased fibroblast proliferation, leading to bilateral internal carotid artery neointimal expansion and progressive stenosis. These findings establish the diagnostic value of hsa-miR-328-3p+hsa-miR-200c-3p in screening moyamoya disease, while also contributing to a deeper understanding of its underlying pathophysiology. Significant differences in microRNA expressions derived from peripheral blood exosomes were observed between moyamoya disease patients and control subjects. Consequently, the utilization of peripheral blood exosomes, specifically hsa-miR-328-3p + hsa-miR-200c-3p, holds potential for diagnostic screening purposes.

Investigating the Impact of SN-38 on Mouse Brain Metabolism Based on Metabolomics.

Purpose: SN-38 (7-ethyl-10-hydroxycamptothecin), the active metabolite of irinotecan, has been extensively studied in drug delivery systems. However, its impact on neural metabolism remains unclear. This study aims to investigate the toxic effects of SN-38 on mouse brain metabolism. Methods: Male mice were divided into an SN-38 group and a control group. The SN-38 group received SN-38 (20 mg/kg/day) via intraperitoneal injection, while the control group was given an equal volume of a blank solvent mixture (DMSO and saline, ratio 1:9). Gas chromatography-mass spectrometry (GC-MS) was employed to analyze differential metabolites in the cortical and hippocampal regions of the SN-38-treated mice. Results: SN-38 induced metabolic disturbances in the central nervous system. Eighteen differential metabolites were identified in the hippocampus and twenty-four in the cortex, with six common to both regions. KEGG pathway enrichment analysis revealed statistically significant alterations in six metabolic pathways in the hippocampus and ten in the cortex (P<0.05). Conclusion: This study is the first to demonstrate the neurotoxicity of SN-38 in male mice through metabolomics. Differential metabolites in the hippocampal and cortical regions were closely linked to purine metabolism, pyrimidine metabolism, amino acid metabolism, and glyceride metabolism, indicating disruptions in the blood-brain barrier, energy metabolism, and central signaling pathways.

Calcitriol attenuates lipopolysaccharide-induced neuroinflammation and depressive-like behaviors by suppressing the P2X7R/NLRP3/caspase-1 pathway.

RATIONALE: Microglia-mediated neuroinflammation is a vital hallmark in progression of depression, while calcitriol exerts anti-inflammatory effects in the brain. The activation of the P2X7 receptor has an important link to neuroinflammation. However, it is unclear whether calcitriol treatment exerts anti-inflammatory effects in association with P2X7R activation. OBJECTIVE: In this study, we assessed the antidepressive and neuroprotective effects of calcitriol on lipopolysaccharide (LPS)-mediated depressive-like behavior, neuroinflammation, and neuronal damage. METHODS: In in vitro experiments, the BV2 cells were exposed to LPS, and the protective effects of calcitriol were assessed. For in vivo experiment, thirty-two male C57BL/6 mice were divided into four groups of control, calcitriol, LPS and LPS + calcitriol. Calcitriol was administered at 1 µg/kg for 14 days and LPS at 1 mg/kg once every other day for 14 days. The control group mice were given equal volumes of vehicles. All treatments were delivered intraperitoneally. RESULTS: The in vitro experiments showed calcitriol inhibited the release of inflammatory mediators induced by LPS in BV2 cells. The in vivo experiments revealed that calcitriol alleviated LPS-induced behavioral abnormalities and spatial learning impairments. Moreover, calcitriol treatment reduced the mRNA levels of pro-inflammatory cytokines, while increasing anti-inflammatory cytokine levels in the hippocampus. Our results further revealed that calcitriol administration attenuated LPS-induced microglia activation by suppressing P2X7R/NLRP3/caspase-1 signaling. Moreover, calcitriol inhibited apoptosis of neurons in the hippocampus as evidenced by expression of apoptosis-related proteins and TUNEL assay. CONCLUSIONS: Collectively, our findings demonstrated that calcitriol exerts antidepressive and neuroprotective effects through the suppression of the P2X7R/NLRP3/caspase-1 pathway both in LPS-induced inflammation models in vitro and in vivo.

The emerging role of exosomes in communication between the periphery and the central nervous system.

Exosomes, membrane-enclosed vesicles, are secreted by all types of cells. Exosomes can transport various molecules, including proteins, lipids, functional mRNAs, and microRNAs, and can be circulated to various recipient cells, leading to the production of local paracrine or distal systemic effects. Numerous studies have proved that exosomes can pass through the blood-brain barrier, thus, enabling the transfer of peripheral substances into the central nervous system (CNS). Consequently, exosomes may be a vital factor in the exchange of information between the periphery and CNS. This review will discuss the structure, biogenesis, and functional characterization of exosomes and summarize the role of peripheral exosomes deriving from tissues like the lung, gut, skeletal muscle, and various stem cell types in communicating with the CNS and influencing the brain's function. Then, we further discuss the potential therapeutic effects of exosomes in brain diseases and the clinical opportunities and challenges. Gaining a clearer insight into the communication between the CNS and the external areas of the body will help us to ascertain the role of the peripheral elements in the maintenance of brain health and illness and will facilitate the design of minimally invasive techniques for diagnosing and treating brain diseases.

Cerebral endothelial cell-derived extracellular vesicles regulate microglial polarization and promote autophagy via delivery of miR-672-5p.

The interaction between cerebral endothelial cells (CEC) and brain parenchymal cells is critical to maintain neurovascular homeostasis, whereas extracellular vesicles (EVs) are essential to mediate the cell-cell communication. Previous researches demonstrated that CEC-derived EVs (CEC-EVs) confer neuroprotective actions. However, the molecular mechanisms remain unknown. In this study, we isolated EVs from CEC and assessed their immune-regulatory actions in microglial cells and mice following lipopolysaccharide (LPS) exposure. We found that CEC-EVs treatment significantly ameliorated LPS-induced inflammatory activation, shifting microglial polarization from pro-inflammatory phenotype to anti-inflammatory phenotype. Meanwhile, microglial cells can effectively internalize CEC-EVs and this process was further enhanced by immune activation. Next, the miRNA microarray analysis revealed that CEC-EVs increased expression of miR-672-5p, which was demonstrated to be the cargo of CEC-EVs. TGFß-activated kinase 1 (TAK1)-binding proteins 2 (TAB2) was identified to be the target of miR-672-5p. Through inhibiting TAB2, miR-672-5p derived from CEC-EVs suppressed TAK1-TAB signaling and thereby mitigating the downstream NF-κB activation. Furthermore, we found that by delivering miR-672-5p, CEC-EVs promoted autophagy and hence stimulating autophagic degradation of NLRP3 inflammasome. Our work firstly revealed the neuroimmune-modulating actions of CEC-EVs and further demonstrated that miR-672-5p secreted from CEC-EVs inhibits microglial pro-inflammatory polarization and facilitates autophagic process via targeting TAB2.

Paclitaxel Induces Neurotoxicity by Disrupting Tricarboxylic Acid Cycle Metabolic Balance in the Mouse Hippocampus.

Objective: It is well known that paclitaxel (PTX)-induced neurotoxicity seriously affects the quality of life of patients and is the main reason for reducing the dose of chemotherapy or even stopping chemotherapy. The current data are limited, and further information is required for practice and verification. The aims of this study were to clarify the molecular mechanism underlying PTX-induced neurotoxicity by combining in vivo and in vitro metabolomics studies and provide new targets for the prevention and treatment of PTX-induced neurotoxicity. Methods: In the in vivo study, a PTX-induced neurotoxicity mouse model was established by intraperitoneal injection of PTX (6 mg/kg every three days) for two consecutive weeks. After verification by water maze tests and HE staining of pathological sections, hippocampal metabolites were measured and the differential metabolites and related metabolic pathways were identified by multivariate statistical analysis. In the in vitro study, we investigated the effects of PTX on mouse hippocampal neuron cells, assessing the concentration and time of administration by MTT assays. After modeling, the relevant metabolites in the TCA cycle were quantified by targeted metabolomics using stable isotope labeling. Finally, the key enzymes of the TCA cycle in tissues and cells were verified by RT-PCR. Results: Administration of PTX to model mice resulted in neurological damage, shown by both water-maze tests and hippocampal tissue sections. Twenty-four metabolites and five associated metabolic pathways were found to differ significantly between the hippocampal tissues of the model and control groups. These included metabolites and pathways related to the TCA cycle and pyruvate metabolism. Metabolomics analysis using stable isotope labeling showed significant changes in metabolites associated with the TCA cycle compared with the control group (P < 0.05). Finally, RT-PCR verified that the expression of key enzymes in the TCA cycle was changed to different degrees in both hippocampal tissues and cells. Conclusion: Our results showed that PTX neurotoxicity in hippocampal tissue and neuron cells was associated with inhibition of the TCA cycle. This inhibition leads to brain insufficiency and impaired metabolism, resulting in various neurotoxic symptoms.

Targeting PDK2 rescues stress-induced impaired brain energy metabolism.

Depression is a mental illness frequently accompanied by disordered energy metabolism. A dysregulated hypothalamus pituitary adrenal axis response with aberrant glucocorticoids (GCs) release is often observed in patients with depression. However, the associated etiology between GCs and brain energy metabolism remains poorly understood. Here, using metabolomic analysis, we showed that the tricarboxylic acid (TCA) cycle was inhibited in chronic social defeat stress (CSDS)-exposed mice and patients with first-episode depression. Decreased mitochondrial oxidative phosphorylation was concomitant with the impairment of the TCA cycle. In parallel, the activity of pyruvate dehydrogenase (PDH), the gatekeeper of mitochondrial TCA flux, was suppressed, which is associated with the CSDS-induced neuronal pyruvate dehydrogenase kinase 2 (PDK2) expression and consequently enhanced PDH phosphorylation. Considering the well-acknowledged role of GCs in energy metabolism, we further demonstrated that glucocorticoid receptors (GR) stimulated PDK2 expression by directly binding to its promoter region. Meanwhile, silencing PDK2 abrogated glucocorticoid-induced PDH inhibition, restored the neuronal oxidative phosphorylation, and improved the flux of isotope-labeled carbon (U-13C] glucose) into the TCA cycle. Additionally, in vivo, pharmacological inhibition and neuron-specific silencing of GR or PDK2 restored CSDS-induced PDH phosphorylation and exerted antidepressant activities against chronic stress exposure. Taken together, our findings reveal a novel mechanism of depression manifestation, whereby elevated GCs levels regulate PDK2 transcription via GR, thereby impairing brain energy metabolism and contributing to the onset of this condition.

New insights into the interplay between autophagy and oxidative and endoplasmic reticulum stress in neuronal cell death and survival.

Autophagy is a dynamic process that maintains the normal homeostasis of cells by digesting and degrading aging proteins and damaged organelles. The effect of autophagy on neural tissue is still a matter of debate. Some authors suggest that autophagy has a protective effect on nerve cells, whereas others suggest that autophagy also induces the death of nerve cells and aggravates nerve injury. In mammals, oxidative stress, autophagy and endoplasmic reticulum stress (ERS) constitute important defense mechanisms to help cells adapt to and survive the stress conditions caused by physiological and pathological stimuli. Under many pathophysiological conditions, oxidative stress, autophagy and ERS are integrated and amplified in cells to promote the progress of diseases. Over the past few decades, oxidative stress, autophagy and ERS and their interactions have been a hot topic in biomedical research. In this review, we summarize recent advances in understanding the interactions between oxidative stress, autophagy and ERS in neuronal cell death and survival.

Impact of a long-term high-fructose diet on systemic metabolic profiles of mice.

Evidence is mounting that chronic high-fructose diets (HFrD) can lead to metabolic abnormalities and cause a variety of diseases. However, the underlying mechanism by which long-term high fructose intake influencing systemic metabolism remains unclarified. This study, therefore, attempted to investigate the impact of a high-fructose diet on metabolic profile. Four-week-old male C57BL/6 mice were fed with 15% fructose solution as their only source of water for 8 weeks. Afterward, gas chromatography-mass spectrometry (GC-MS) was employed to investigate the comprehensive metabolic profile of serum, muscle, liver, heart, white adipose, brain, and kidney tissues, and multivariate analyses including principal component analysis (PCA) and orthogonal partial least squared-discriminant analysis (OPLS-DA) were applied to screen for differential metabolite expression between the HFrD and control groups. Furthermore, the MetaboAnalyst 5.0 (http://www.metaboanalyst.ca) and Kyoto Encyclopedia of Genes and Genomes database (KEGG; http://www.kegg.jp) were employed to portray a detailed metabolic network. This study identified 62 metabolites related to HFrD and 10 disturbed metabolic pathways. The results indicated that high fructose intake mainly influenced amino acid metabolism and biosynthesis (glycine, serine, and threonine metabolism; aspartate, and glutamate metabolism; phenylalanine, tyrosine, and tryptophan biosynthesis, and arginine biosynthesis pathways), glutathione metabolism, sphingolipid metabolism, and glyoxylate and dicarboxylate metabolism in serum, whereas these pathways were suppressed in the brain. Starch and sucrose metabolism in muscle was also disrupted. These results elucidate the effects of long-term high fructose consumption on the metabolic profiles of various tissues and provide new insight for the identification of potential metabolic biomarkers and pathways disrupted by high fructose.

A GC-MS-based untargeted metabolomics approach for comprehensive metabolic profiling of vancomycin-induced toxicity in mice.

Background: Vancomycin is a glycopeptide antibiotic that is commonly used for severe drug-resistant infections treatment. Application of vancomycin frequently leads to severe ototoxicity, hepatotoxicity, and nephrotoxicity; however, the comprehensive metabolic analysis of vancomycin-induced toxicity is lacking. Purpose: This study attempted to investigate the metabolic changes after vancomycin administration in mice. Methods: Experimental mice (n = 9) received continuous intraperitoneal injection of vancomycin (400 mg/kg) every day for 7 days, and mice in control group (n = 9) were treated with the same amount of normal saline. Pathological changes of the kidney were examined using haematoxylin and eosin (HE) staining. A gas chromatography-mass spectrometry (GC-MS) approach was used to identify discriminant metabolites in serum and various organs including the heart, liver, kidney, spleen, cerebral cortex, hippocampus, inner ear, lung, and intestine. The potential metabolites were identified using orthogonal partial least squares discrimination analysis (OPLS-DA). Subsequently, the MetaboAnalyst 5.0 (http://www.metaboanalyst.ca) and Kyoto Encyclopedia of Genes and Genomes database (KEGG, http://www.kegg.jp) were employed to depict the metabolic pathways. Results: Compared with the control group, the vancomycin induced 13, 17, 27, 22, 16, 10, 17, 11, 10, and 7 differential metabolites in the serum, liver, kidney, heart, cerebral cortex, lung, spleen, intestine, hippocampus, and inner ear, respectively. Further pathway analyses identified that amino acids metabolism, fatty acids biosynthesis, energy metabolism, and lipid metabolism were disrupted after VCM exposure. Conclusion: Vancomycin affects the metabolism in various organs in mice, which provides new insights for identification of vancomycin-induced toxicity, and facilitate to better understanding of the metabolic pathogenesis of vancomycin.

Comprehensive Analysis of Metabolic Changes in Male Mice Exposed to Sodium Valproate Based on GC-MS Analysis.

Purpose: Sodium valproate (VPA) is the most widely used broad-spectrum antiepileptic first-line drug in clinical practice and is effective against various types of epilepsy. However, VPA can induce severe cardiotoxicity, nephrotoxicity, hepatotoxicity, and neurotoxicity, which limits its use. Metabolomic studies of VPA-induced toxicity have focused primarily on changes in serum and urine metabolites but have not evaluated changes in major organs or tissues. Methods: Central target tissues (intestine, lung, liver, hippocampus, cerebral cortex, inner ear, spleen, kidney, heart, and serum) were analyzed using gas chromatography mass spectrometry to comprehensively evaluate VPA toxicity in mouse models. Results: Multivariate analyses, including orthogonal projections of the latent structure and Student's t test, indicated that depending on the matrix used in the study (the intestine, lung, liver, hippocampus, cerebral cortex, inner ear, spleen, kidney, heart or serum) the number of metabolites differed, the lung being the poorest and the kidney the richest in number. Conclusion: These metabolites were closely related and were found to participate in 12 key pathways related to amino acid, fatty acid, and energy metabolism, revealing that the toxic mechanism of VPA may involve oxidative stress, inflammation, amino acid metabolism, lipid metabolism, and energy disorder.

Ghrelin ameliorates diabetes-associated behavioral deficits and NLRP3 inflammasome activation via autophagic flux enhancement.

Ghrelin has recently been associated with the development of diabetes comorbid with depression, but its underlying molecular mechanisms remains poorly understood. Here, molecular and histological methods were applied both in vivo and in vitro studies to investigate the mechanisms of ghrelin in diabetes comorbid with depression. Our results demonstrated the anti-depressive, anxiolytic, and neuroprotective effects of ghrelin, as evidenced by the amelioration of anxiety- and depression-like behaviors, reduction in apoptosis, and preservation of neuron integrity in streptozotocin (STZ)-treated rats. STZ treatment induced M1-phenotypic microglial polarization, accompanied by neuroinflammation, which was reversed by ghrelin treatment. Further exploration showed that autophagy was inhibited, the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome and nuclear factor (NF)-κB signaling pathway were activated in STZ rats. In line with the in vivo results, ghrelin could suppress the NLRP3 inflammasome and NF-κB signaling pathway activation via the amelioration of impaired autophagic flux in microglial BV2 cells. Importantly, clinical evidence further verified the anti-inflammatory and antidepressant effects of ghrelin. Collectively, these results suggested that ghrelin ameliorates diabetes-associated behavioral deficits and NLRP3 inflammasome activation via autophagic flux enhancement, highlighting the importance of ghrelin as a potential target of immune regulation in diabetes comorbid with depression.

Therapeutic effect of extracellular vesicles from different cell sources in traumatic brain injury.

Extracellular vesicles (EVs) are biologically active membrane vesicles secreted by many cells in the body. A variety of nucleic acids, proteins, and other biologically active substances in EVs can be used to exchange and transmit information between cells, thereby affecting the progression of various diseases. Numerous studies have demonstrated that EVs not only regulate changes in brain physiology but also regulate synaptic plasticity and neuronal regeneration in traumatic brain injury (TBI), which opens a new approach for the treatment of TBI. In view of the fact that most human cells can secrete EVs, and relevant experiments have proved that different doses of EVs have different therapeutic effects on TBI. To this end, this paper reviews the therapeutic effects of EVs from different cell sources and their doses on TBI.

Targeted metabolomics analysis of serum amino acid profiles in patients with Moyamoya disease.

Amino acids are one of the main metabolites in the body, and provide energy for the body and brain. The purpose of this study is to provide a profile of amino acid changes in the serum of patients with Moyamoya disease (MMD) and identify potential disease biomarkers. In this paper, we quantitatively determined the serum amino acid metabolic profiles of 43 MMD patients and 42 healthy controls (HCs). T test, multivariate statistical analysis, and receiver operating characteristic (ROC) curve analysis were used to identify candidate markers. Thirty-nine amino acids were quantified, and 12 amino acid levels differed significantly between the MMD patients and HCs. Moreover, based on ROC curve analysis, four amino acid (L-methionine, L-glutamic acid, ß-alanine and o-phosphoserine) biomarkers showed high sensitivity and specificity (AUC > 0.90), and showed the best sensitivity and specificity in MetaboAnalyst 5.0 using binary logistic regression analysis. We have provided serum amino acid metabolic profiles of MMD patients, and identified four potential biomarkers which may both provide clinicians with an objective diagnostic method for early detection of MMD and further our understanding of MMD pathogenesis.

Research Progress on the Correlation Between Vitamin D and Neurological Disorders.

AIM: To review the correlation between vitamin D (VD) and several common neurological disorders with the aim of providing directions and ideas for using VD to treat neurological disorders. MATERIAL AND METHODS: VD, 1,25-dihydroxyvitamin D3, stroke, epilepsy, and cognitive dysfunction were used as keywords. The PubMed and Embase databases were searched for articles published from 2010 to 2021. The inclusion criteria were as follows: clear introduction of the research sample, detailed explanation of the sample selection in the research, intervention, and control measures, and available odds ratio and 95% confidence interval. The exclusion criteria were as follows: duplicate reports, defects in research design and poor quality, incomplete data and unclear results, and unmodifiable errors in the statistical method. RESULTS: Initially, 1,360 articles were retrieved from the PubMed and Embase databases. Finally, 81 articles were included, 76 of which were published within the last 5 years. CONCLUSION: VD deficiency is very common in the population and is associated with a variety of neurological diseases. VD, a neuroactive steroid, plays an important role in the protection of the central nervous system. In contrast, stroke can cause epilepsy and varying degrees of changes in cognitive function. Furthermore, seizure and epilepsy can cause changes in cognitive function. The degree of alteration in cognitive function affects the occurrence and progression of stroke and epilepsy. Therefore, VD can be used for the comprehensive treatment of neurological diseases.

Platelet-to-Lymphocyte Ratio and Neutrophil-to-Lymphocyte Ratio in Patients With Newly Diagnosed Moyamoya Disease: A Cross-Sectional Study.

Inflammation has been proven to be one of the key factors in the pathogenesis of moyamoya disease (MMD). Platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR) are cheap and reliable biomarkers of inflammation. Nevertheless, evidence regarding the relationship among PLR and NLR in patients with MMD is limited. The focus of this subject was to explore the relationship between PLR and NLR in patients with newly diagnosed MMD. Patients and methods: A cross-sectional study was performed including 261 patients with diagnosed MMD for the first time who were enrolled from our hospital, from 24 March 2013 to 24 December 2018. The clinical characteristics were collected for each patient. Univariate analysis, smooth curve fitting and multivariate piecewise linear regression were showed. Results: The mean levels or median values (interquartile range) of PLR and NLR were 146.979 ± 51.203 and 2.241 (1.589-2.984), respectively. A significant positive correlation between PLR and NLR levels (P < 0.001) was showed by the univariate analysis. Furthermore, a non-linear relationship was detected between PLR and NLR by smooth curve fitting after adjusting for potential confounders. A multivariate piecewise linear regression model revealed a significant positive correlation between PLR and NLR when the PLR level was lower than 219.82 (ß 0.012, 95% CI 0.005, 0.019; P = 0.001). PLR was also significantly positively associated with NLR when PLR concentrations were >219.82 (ß 0.098, 95% CI 0.069, 0.128; P < 0.001). Conclusion: There seemed to be a positive association between PLR and NLR in patients with MMD. This may help to further explain the role of inflammation in the occurrence and progress of MMD.

Calcitriol confers neuroprotective effects in traumatic brain injury by activating Nrf2 signaling through an autophagy-mediated mechanism.

BACKGROUND: The present study aimed to further explore the potential interaction between oxidative stress and autophagy in the progression of traumatic brain injury (TBI) and therapeutic mechanism of calcitriol, the active form of vitamin D (VitD). METHODS: Neuroprotective effects of calcitriol were examined following TBI. We further evaluated the impacts of TBI and calcitriol treatment on autophagic process and nuclear factor E2-related factor 2 (Nrf2) signaling. RESULTS: We found that treatment of calcitriol markedly ameliorated the neurological deficits and histopathological changes following TBI. The brain damage impaired autophagic flux and impeded Nrf2 signaling, the major regulator in antioxidant response, consequently leading to uncontrolled and excessive oxidative stress. Meanwhile, calcitriol promoted autophagic process and activated Nrf2 signaling as evidenced by the reduced Keap1 expression and enhanced Nrf2 translocation, thereby mitigating TBI-induced oxidative damage. In support, we further found that chloroquine (CQ) treatment abrogated calcitriol-induced autophagy and compromised Nrf2 activation with increased Keap1 accumulation and reduced expression of Nrf2-targeted genes. Additionally, both CQ treatment and Nrf2 genetic knockout abolished the protective effects of calcitriol against both TBI-induced neurological deficits and neuronal apoptosis. CONCLUSIONS: Therefore, our work demonstrated a neuroprotective role of calcitriol in TBI by triggering Nrf2 activation, which might be mediated by autophagy.

Activation of angiotensin-converting enzyme 2/angiotensin (1-7)/mas receptor axis triggers autophagy and suppresses microglia proinflammatory polarization via forkhead box class O1 signaling.

Brain renin-angiotensin (Ang) system (RAS) is implicated in neuroinflammation, a major characteristic of aging process. Angiotensin (Ang) II, produced by angiotensin-converting enzyme (ACE), activates immune system via angiotensin type 1 receptor (AT1), whereas Ang(1-7), generated by ACE2, binds with Mas receptor (MasR) to restrain excessive inflammatory response. Therefore, the present study aims to explore the relationship between RAS and neuroinflammation. We found that repeated lipopolysaccharide (LPS) treatment shifted the balance between ACE/Ang II/AT1 and ACE2/Ang(1-7)/MasR axis to the deleterious side and treatment with either MasR agonist, AVE0991 (AVE) or ACE2 activator, diminazene aceturate, exhibited strong neuroprotective actions. Mechanically, activation of ACE2/Ang(1-7)/MasR axis triggered the Forkhead box class O1 (FOXO1)-autophagy pathway and induced superoxide dismutase (SOD) and catalase (CAT), the FOXO1-targeted antioxidant enzymes. Meanwhile, knockdown of MasR or FOXO1 in BV2 cells, or using the selective FOXO1 inhibitor, AS1842856, in animals, suppressed FOXO1 translocation and compromised the autophagic process induced by MasR activation. We further used chloroquine (CQ) to block autophagy and showed that suppressing either FOXO1 or autophagy abrogated the anti-inflammatory action of AVE. Likewise, Ang(1-7) also induced FOXO1 signaling and autophagic flux following LPS treatment in BV2 cells. Cotreatment with AS1842856 or CQ all led to autophagic inhibition and thereby abolished Ang(1-7)-induced remission on NLRP3 inflammasome activation caused by LPS exposure, shifting the microglial polarization from M1 to M2 phenotype. Collectively, these results firstly illustrated the mechanism of ACE2/Ang(1-7)/MasR axis in neuroinflammation, strongly indicating the involvement of FOXO1-mediated autophagy in the neuroimmune-modulating effects triggered by MasR activation.

RNF213 gene silencing upregulates transforming growth factor ß1 expression in bone marrow-derived mesenchymal stem cells and is involved in the onset of Moyamoya disease.

Moyamoya disease (MMD) is a chronic and progressive cerebrovascular occlusion disease, the precise etiology of which is poorly understood. Ring finger protein 213 (RNF213) has been previously identified as a susceptibility gene that serves an important role in angiogenesis, where it has been shown to be closely associated with the onset of MMD. Patients with MMD exhibit increased expression levels of various pro-inflammatory molecules and angiogenic factors. Under certain conditions, bone marrow mesenchymal stem cells (BMSCs) have the ability to differentiate to form neuron-like and microglia-like cells. In the present study, a total of 40 MMD patients and 40 healthy individuals were enrolled. ELISA assays revealed that the expression of serum vascular endothelial growth factor (VEGF) and transforming growth factor ß1 (TGF-ß1) were higher than that in healthy controls. Furthermore, rat BMSCs (rBMSCs) were isolated and cultured using the whole bone marrow adherence method, which were then phenotyped using flow cytometry. Osteogenic and adipogenic differentiation were determined by using Alizarin red and oil red O staining, respectively. RNF213 was knocked-down using a lentivirus-mediated short hairpin RNA system in passage three rBMSCs, and successful transfection of the RNF213 was confirmed by RT-qPCR and fluorescence imaging. The expression levels of VEGF and TGF-ß1 in these rBMSCs were measured on days 7 and 14, respectively. The results demonstrated that RNF213 knockdown upregulated TGF-ß1 at both protein and mRNA levels, but did not exert any effect on VEGF gene expression. In conclusion, these findings suggested that that RNF213 knockdown may contribute to aberrant TGF-ß1 expression via a pathway that remains to be unidentified, indicating that quantitative changes in RNF213 gene expression may serve an important role in the pathogenesis of MMD.

Inhibition of PTEN Ameliorates Secondary Hippocampal Injury and Cognitive Deficits after Intracerebral Hemorrhage: Involvement of AKT/FoxO3a/ATG-Mediated Autophagy.

Spontaneous intracerebral hemorrhage (ICH) commonly causes secondary hippocampal damage and delayed cognitive impairments, but the mechanisms remain elusive. Here, we sought to identify the molecular mechanisms underlying these hemorrhagic outcomes in a rat autologous blood model of ICH. First, a significant increase in phosphatase and tensin homolog (PTEN) expression was observed in nonhemorrhagic ipsilateral hippocampus. However, systemic administration of PTEN inhibitor BPV or hippocampal injection of PTEN siRNA could prevent hippocampal neuronal injury and cognitive dysfunctions after ICH. Furthermore, we also found that ICH robustly triggered autophagic neuronal death in the ipsilateral hippocampus, but which were strongly reduced by PTEN knockdown. Notably, suppression of autophagy effectively attenuated poststroke hippocampal inflammation, neuronal damage, and cognitive decline, suggesting the beneficial effects of PTEN deletion was associated with autophagy inactivation. Specifically, PTEN antagonized the PI3K/AKT signaling and downstream effector FoxO3a phosphorylation and subsequently enhanced nuclear translocation of FoxO3a to drive proautophagy gene program, but these changes were diminished upon PTEN inhibition. More importantly, lentivirus-mediated FoxO3a overexpression apparently abrogated the antiauotphagy effect of PTEN deletion via enhancing autophagy-related gene (ATG) transcription. Collectively, these results suggest that knockdown of PTEN alleviated progressive hippocampal injury and cognitive deficits by suppression of autophagy induction involving the AKT/FoxO3a/ATG axis after ICH. Thus, this study provides a novel and promising therapeutic target for the treatment of hemorrhagic stroke.