Orosomucoid1: Involved in vascular endothelial growth factor-induced blood-brain barrier leakage after ischemic stroke in mouse

Orosomucoid-1 Arises as a Shared Altered Protein in Two Models of Multiple Sclerosis

Multiple sclerosis (MS) is a complex autoimmune and neurodegenerative disorder that affects the central nervous system (CNS). It is characterized by a heterogeneous disease course involving demyelination and inflammation. In this study, we utilized two distinct animal models, cuprizone (CPZ)-induced demyelination and experimental autoimmune encephalomyelitis (EAE), to replicate various aspects of the disease. We aimed to investigate the differential CNS responses by examining the proteomic profiles of EAE mice during the peak disease (15 days post-induction) and cuprizone-fed mice during the acute phase (38 days). Specifically, we focused on two different regions of the CNS: the dorsal cortex (Cx) and the entire spinal cord (SC). Our findings revealed varied glial, synaptic, dendritic, mitochondrial, and inflammatory responses within these regions for each model. Notably, we identified a single protein, Orosomucoid-1 (Orm1), also known as Alpha-1-acid glycoprotein 1 (AGP1), that consistently exhibited alterations in both models and regions. This study provides insights into the similarities and differences in the responses of these regions in two distinct demyelinating models.

Integrative Analysis of Single-Cell and Bulk Sequencing Data Depicting the Expression and Function of P2ry12 in Microglia Post Ischemia–Reperfusion Injury

P2ry12 is a microglial marker gene. Recently, increasing evidence has demonstrated that its expression levels can vary in response to different CNS disorders and can affect microglial functions, such as polarization, plasticity, and migration. However, the expression and function of P2ry12 in microglia during ischemia–reperfusion injury (IRI) remain unclear. Here, we developed a computational method to obtain microglia-specific P2ry12 genes (MSPGs) using sequencing data associated with IRI. We evaluated the change in comprehensive expression levels of MSPGs during IRI and compared it to the expression of P2ry12 to determine similarity. Subsequently, the MSPGs were used to explore the P2ry12 functions in microglia through bioinformatics. Moreover, several animal experiments were also conducted to confirm the reliability of the results. The expression of P2ry12 was observed to decrease gradually within 24 h post injury. In response, microglia with reduced P2ry12 expression showed an increase in the expression of one receptor-encoding gene (Flt1) and three ligand-encoding genes (Nampt, Igf1, and Cxcl2). Furthermore, double-labeling immunofluorescence staining revealed that inhibition of P2ry12 blocked microglial migration towards vessels during IRI. Overall, we employ a combined computational and experimental approach to successfully explore P2ry12 expression and function in microglia during IRI.

DIA-based technology explores hub pathways and biomarkers of neurological recovery in ischemic stroke after rehabilitation

Objective

Ischemic stroke (IS) is a common disease that causes severe and long-term neurological disability in people worldwide. Although rehabilitation is indispensable to promote neurological recovery in ischemic stroke, it is limited to providing a timely and efficient reference for developing and adjusting treatment strategies because neurological assessment after stroke treatment is mostly performed using scales and imaging. Therefore, there is an urgent need to find biomarkers that can help us evaluate and optimize the treatment plan.

Methods

We used data-independent acquisition (DIA) technology to screen differentially expressed proteins (DEPs) before and after ischemic stroke rehabilitation treatment, and then performed Gene Ontology (GO) and pathway enrichment analysis of DEPs using bioinformatics tools such as KEGG pathway and Reactome. In addition, the protein-protein interaction (PPI) network and modularity analysis of DEPs were integrated to identify the hub proteins (genes) and hub signaling pathways for neurological recovery in ischemic stroke. PRM-targeted proteomics was also used to validate some of the screened proteins of interest.

Results

Analyzing the serum protein expression profiles before and after rehabilitation, we identified 22 DEPs that were upregulated and downregulated each. Through GO and pathway enrichment analysis and subsequent PPI network analysis constructed using STRING data and subsequent Cytoscape MCODE analysis, we identified that complement-related pathways, lipoprotein-related functions and effects, thrombosis and hemostasis, coronavirus disease (COVID-19), and inflammatory and immune pathways are the major pathways involved in the improvement of neurological function after stroke rehabilitation.

Conclusion

Complement-related pathways, lipoprotein-related functions and effects, thrombosis and hemostasis, coronavirus disease (COVID-19), and inflammation and immunity pathways are not only key pathways in the pathogenesis of ischemic stroke but also the main pathways of action of rehabilitation therapy. In addition, IGHA1, LRG1, IGHV3-64D, and CP are upregulated in patients with ischemic stroke and downregulated after rehabilitation, which may be used as biomarkers to monitor neurological impairment and recovery after stroke.

Bioinformatic analysis identifies potential key genes of epilepsy

Background

Epilepsy is one of the most common brain disorders worldwide. It is usually hard to be identified properly, and a third of patients are drug-resistant. Genes related to the progression and prognosis of epilepsy are particularly needed to be identified.

Methods

In our study, we downloaded the Gene Expression Omnibus (GEO) microarray expression profiling dataset GSE143272. Differentially expressed genes (DEGs) with a fold change (FC) >1.2 and a P-value <0.05 were identified by GEO2R and grouped in male, female and overlapping DEGs. Functional enrichment analysis and Protein-Protein Interaction (PPI) network analysis were performed.

Results

In total, 183 DEGs overlapped (77 ups and 106 downs), 302 DEGs (185 ups and 117 downs) in the male dataset, and 750 DEGs (464 ups and 286 downs) in the female dataset were obtained from the GSE143272 dataset. These DEGs were markedly enriched under various Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) terms. 16 following hub genes were identified based on PPI network analysis: ADCY7, C3AR1, DEGS1, CXCL1 in male-specific DEGs, TOLLIP, ORM1, ELANE, QPCT in female-specific DEGs and FCAR, CD3G, CLEC12A, MOSPD2, CD3D, ALDH3B1, GPR97, PLAUR in overlapping DEGs.

Conclusion

This discovery-driven study may be useful to provide a novel insight into the diagnosis and treatment of epilepsy. However, more experiments are needed in the future to study the functional roles of these genes in epilepsy.

Lipocalin-2 may produce damaging effect after cerebral ischemia by inducing astrocytes classical activation

Background

Functions of astrocytes in the rehabilitation after ischemic stroke, especially their impacts on inflammatory processes, remain controversial. This study uncovered two phenotypes of astrocytes, of which one was helpful, and the other harmful to anoxic neurons after brain ischemia.

Methods

We tested the levels of inflammatory factors including TNF-a, IL-6, IL-10, iNOS, IL-1beta, and CXCL10 in primary astrocytes at 0 h, 6 h, 12 h, 24 h, and 48 h after OGD, grouped the hypoxia astrocytes into iNOS-positive (iNOS(+)) and iNOS-negative (iNOS(−)) by magnetic bead sorting, and then co-cultured the two groups of cells with OGD-treated neurons for 24 h. We further verified the polarization of astrocytes in vivo by detecting the co-localization of iNOS, GFAP, and Iba-1 on MCAO brain sections. Lentivirus overexpressing LCN2 and LCN2 knockout mice (#024630. JAX, USA) were used to explore the role of LCN2 in the functional polarization of astrocytes. 7.0-T MRI scanning and the modified Neurological Severity Score (mNSS) were used to evaluate the neurological outcomes of the mice.

Results

After oxygen-glucose deprivation (OGD), iNOS mRNA expression increased to the peak at 6 h in primary astrocytes, but keep baseline expression in LCN2-knockout astrocytes. In mice with transient middle cerebral artery occlusion (tMCAO), LCN2 was proved necessary for astrocyte classical activation. In LCN2 knockout mice with MCAO, no classically activated astrocytes were detected, and smaller infarct volumes and better neurological functions were observed.

Conclusions

The results indicated a novel pattern of astrocyte activation after ischemic stroke and lipocalin-2 (LCN2) plays a key role in polarizing and activating astrocytes.

Integrated Proteomics and Metabolomic Analyses of Plasma Injury Biomarkers in a Serious Brain Trauma Model in Rats

Diffuse axonal injury (DAI) is a prevalent and serious brain injury with significant morbidity and disability. However, the underlying pathogenesis of DAI remains largely unclear, and there are still no objective laboratory-based tests available for clinicians to make an early diagnosis of DAI. An integrated analysis of metabolomic data and proteomic data may be useful to identify all of the molecular mechanisms of DAI and novel potential biomarkers. Therefore, we established a rat model of DAI, and applied an integrated UPLC-Q-TOF/MS-based metabolomics and isobaric tag for relative and absolute quantitation (iTRAQ)-based proteomic analysis to obtain unbiased profiling data. Differential analysis identified 34 metabolites and 43 proteins in rat plasma of the injury group. Two metabolites (acetone and 4-Hydroxybenzaldehyde) and two proteins (Alpha-1-antiproteinase and Alpha-1-acid glycoprotein) were identified as potential biomarkers for DAI, and all may play important roles in the pathogenesis of DAI. Our study demonstrated the feasibility of integrated metabolomics and proteomics method to uncover the underlying molecular mechanisms of DAI, and may help provide clinicians with some novel diagnostic biomarkers and therapeutic targets.

Identification and functional analysis of differentially expressed genes associated with cerebral ischemia/reperfusion injury through bioinformatics methods

Cerebral ischemia/reperfusion (I/R) injury results in detrimental complications. However, little is known about the underlying molecular mechanisms involved in the reperfusion stage. The aim of the present study was to identify a gene expression profile associated with cerebral ischemia/reperfusion injury. The GSE23160 dataset, which comprised data from sham control samples and post-I/R injury brain tissues that were obtained using a middle cerebral artery occlusion (MCAO) model at 2, 8 and 24 h post-reperfusion, was downloaded from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) in the MCAO samples compared with controls were screened using the GEO2R web tool. Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis for DEGs was performed using the online tool DAVID. Furthermore, a protein-protein interaction (PPI) network was constructed using the STRING database and Cytoscape software. In total, 32 DEGs at 2 h post-reperfusion, 39 DEGs at 8 h post-reperfusion and 91 DEGs at 24 h post-reperfusion were identified, while 15 DEGs were common among all three groups. GO analysis revealed that the DEGs at all three time-points were enriched in ‘chemotaxis’ and ‘inflammatory response’ terms, while KEGG pathway analysis demonstrated that DEGs were significantly enriched in the ‘chemokine signaling pathway’. Furthermore, following PPI network construction, Cxcl1 was identified as the only hub gene that was common among all three time-points. In conclusion, the present study has demonstrated a global view of the potential molecular differences following cerebral I/R injury and may contribute to an improved understanding of the reperfusion stage, which may ultimately aid in the development of future clinical strategies.

A novel IL-1RA-PEP fusion protein alleviates blood-brain barrier disruption after ischemia-reperfusion in male rats

BACKGROUND

Current options to treat clinical relapse in inflammatory central nervous system (CNS) conditions such as cerebral ischemia-reperfusion injury are limited, and agents that are more effective are required. Disruption of the blood-brain barrier is an early feature of lesion formation that correlates with clinical exacerbation and facilitates the entry of inflammatory medium and inflammatory cells. Interleukin-1 receptor antagonist (IL-1RA) is a naturally occurring anti-inflammatory antagonist of the interleukin-1 (IL-1) family. The broad-spectrum anti-inflammatory effects of IL-1RA have been investigated against various forms of neuroinflammation. However, the effect of IL-1RA on blood-brain barrier disruption following ischemia-reperfusion has not been reported.

METHODS

In this study, we investigated the effects of IL-1RA and a novel protein (IL-1RA-PEP) that was fused to IL-1RA with a cell penetrating peptide, on blood-brain barrier integrity, in male rats subjected to transient middle cerebral artery occlusion.

RESULTS

After intravenous administration, IL-1RA-PEP (50 mg/kg) penetrated cerebral tissues more effectively than IL-1RA. Moreover, it preserved blood-brain barrier integrity, attenuated changes in expression and localization of tight junction proteins and matrix metalloproteinases, and enhanced angiogenesis in ischemic brain tissue. Further study suggested that the effects of IL-1RA-PEP on preserving blood-brain barrier integrity might be closely correlated with the p65/NF-κB pathway, as evidenced by the effects of the inhibitor JSH-23.

CONCLUSIONS

Collectively, our results demonstrated that IL-1RA-PEP could effectively penetrate the brain of rats with middle cerebral artery occlusion and ameliorate blood-brain barrier disruption. This finding might represent its novel therapeutic potential in the treatment of the cerebral ischemia-reperfusion injury.

MicroRNA-1906, a Novel Regulator of Toll-Like Receptor 4, Ameliorates Ischemic Injury after Experimental Stroke in Mice

Toll-like receptor 4 (TLR4) is a proinflammatory cascade initiator in poststroke inflammation. In this study, miR-1906, a novel regulator of TLR4, was identified via in silico analysis and microRNA profiling in male adult mice and its expression was then quantitated in the ischemic hemisphere. We found miR-1906 to be significantly brain enriched in the ischemic hemisphere and even more drastically enriched in the peri-infarct regions. Furthermore, in vitro experiments demonstrated that, during oxygen-glucose deprivation, miR-1906 expression was increased in glial cells but decreased in neurons. Surprisingly, despite the augmentation of intracellular abundance, miR-1906 expression in extracellular vesicles was decreased in astrocyte cell culture supernatants, suggesting reduced sources of miR-1906 from glia to neurons. When exogenous miR-1906 was administered, decreased TLR4 protein expression was observed both in vitro and in vivo Using Cy3 labeling, exogenous miR-1906 uptake by astrocytes, microglia, and neurons was visualized directly in vivo Reduced infarct volumes and improved functional outcomes were observed in middle cerebral artery occlusion mice receiving miR-1906. However, the protective effects of miR-1906 disappeared with the genetic knock-out of TLR4, suggesting that TLR4 is a major target of miR-1906 through which the microRNA exerts its therapeutic effects.SIGNIFICANCE STATEMENT The current study identified miR-1906 as a novel specific regulator of Toll-like receptor 4 (TLR4) and depicted its distinct expression patterns in different cerebral regions and cell types during ischemic attack. Therefore, the therapeutic supplementation of miR-1906 can be beneficial in the modulation of poststroke inflammation. Using Cy3 labeling, exogenous miR-1906 expression was visualized and shown to enter astrocytes, microglia, and neurons successfully in vivo Supplemental therapeutic miR-1906 resulted in reduced TLR4 expression and improved outcomes after middle cerebral artery occlusion in a mouse model, but its neuroprotective function was TLR4 dependent, suggesting that TLR4 is a major target of miR-1906.

GSK-3β as a target for protection against transient cerebral ischemia

Stroke remains the leading cause of death and disability worldwide. This fact highlights the need to search for potential drug targets that can reduce stroke-related brain damage. We showed recently that a glycogen synthase kinase-3β (GSK-3β) inhibitor attenuates tissue plasminogen activator-induced hemorrhagic transformation after permanent focal cerebral ischemia. Here, we examined whether GSK-3β inhibition mitigates early ischemia-reperfusion stroke injury and investigated its potential mechanism of action. We used the rat middle cerebral artery occlusion (MCAO) model to mimic transient cerebral ischemia. At 3.5 h after MCAO, cerebral blood flow was restored, and rats were administered DMSO (vehicle, 1% in saline) or GSK-3β inhibitor TWS119 (30 mg/kg) by intraperitoneal injection. Animals were sacrificed 24 h after MCAO. TWS119 treatment reduced neurologic deficits, brain edema, infarct volume, and blood-brain barrier permeability compared with those in the vehicle group. TWS119 treatment also increased the protein expression of β-catenin and zonula occludens-1 but decreased β-catenin phosphorylation while suppressing the expression of GSK-3β. These results indicate that GSK-3β inhibition protects the blood-brain barrier and attenuates early ischemia-reperfusion stroke injury. This protection may be related to early activation of the Wnt/β-catenin signaling pathway.

Elevated levels of protein AMBP in cerebrospinal fluid of women with preeclampsia compared to normotensive pregnant women

PURPOSE

To investigate the cerebrospinal fluid (CSF) proteome of patients with preeclampsia (PE) and normotensive pregnant women, in order to provide a better understanding of brain involvement in PE.

EXPERIMENTAL DESIGN

Ninety-eight CSF samples (43 women with PE and 55 normotensive controls) were analyzed by LC-MS/MS proteome profiling. CSF was obtained during the spinal puncture before caesarean delivery.

RESULTS

Eight proteins were higher abundant and 17 proteins were lower abundant in patients with PE. The most significantly differentially abundant protein was protein AMBP (alpha-1-microglobulin/bikunin precursor). This finding was validated by performing an ELISA experiment (p = 0.002).

CONCLUSIONS AND CLINICAL RELEVANCE

The current study showed a clear difference between the protein profiles of CSF from patients with PE and normotensive pregnant women. Protein AMBP is a precursor of a heme-binding protein that counteracts the damaging effects of free hemoglobin, which may be related to the presence of free hemoglobin in CSF. Protein levels showed correlations with clinical symptoms during pregnancy and postpartum. To our knowledge, this is the first LC-MS/MS proteome profiling study on a unique set of CSF samples from (severe) preeclamptic patients and normotensive pregnant women.

The Acute-Phase Protein Orosomucoid Regulates Food Intake and Energy Homeostasis via Leptin Receptor Signaling Pathway

The acute-phase protein orosomucoid (ORM) exhibits a variety of activities in vitro and in vivo, notably modulation of immunity and transportation of drugs. We found in this study that mice lacking ORM1 displayed aberrant energy homeostasis characterized by increased body weight and fat mass. Further investigation found that ORM, predominantly ORM1, is significantly elevated in sera, liver, and adipose tissues from the mice with high-fat diet (HFD)-induced obesity and db/db mice that develop obesity spontaneously due to mutation in the leptin receptor (LepR). Intravenous or intraperitoneal administration of exogenous ORM decreased food intake in C57BL/6, HFD, and leptin-deficient ob/ob mice, which was absent in db/db mice and was significantly reduced in mice with arcuate nucleus (ARC) LepR knockdown, whereas enforced expression of ORM1 in ARC significantly decreased food intake, body weight, and serum insulin level. Furthermore, we found that ORM is able to bind directly to LepR and activate the receptor-mediated JAK2-STAT3 signaling in hypothalamus tissue and GT1-7 cells, which was derived from hypothalamic tumor. These data indicated that ORM could function through LepR to regulate food intake and energy homeostasis in response to nutrition status. Modulating the expression of ORM is a novel strategy for the management of obesity and related metabolic disorders.

Integrated Analysis of Expression Profile Based on Differentially Expressed Genes in Middle Cerebral Artery Occlusion Animal Models

Stroke is one of the most common causes of death, only second to heart disease. Molecular investigations about stroke are in acute shortage nowadays. This study is intended to explore a gene expression profile after brain ischemia reperfusion. Meta-analysis, differential expression analysis, and integrated analysis were employed on an eight microarray series. We explored the functions and pathways of target genes in gene ontology (GO) enrichment analysis and constructed a protein-protein interaction network. Meta-analysis identified 360 differentially expressed genes (DEGs) for Mus musculus and 255 for Rattus norvegicus. Differential expression analysis identified 44 DEGs for Mus musculus and 21 for Rattus norvegicus. Timp1 and Lcn2 were overexpressed in both species. The cytokine-cytokine receptor interaction and chemokine signaling pathway were highly enriched for the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. We have exhibited a global view of the potential molecular differences between middle cerebral artery occlusion (MCAO) animal model and sham for Mus musculus or Rattus norvegicus, including the biological process and enriched pathways in DEGs. This research helps contribute to a clearer understanding of the inflammation process and accurate identification of ischemic infarction stages, which might be transformed into a therapeutic approach.

Vitexin reduces hypoxia-ischemia neonatal brain injury by the inhibition of HIF-1alpha in a rat pup model

Previous studies have demonstrated that the early suppression of HIF-1α after hypoxia-ischemia (HI) injury provides neuroprotection. Vitexin (5, 7, 4-trihydroxyflavone-8-glucoside), an HIF-1α inhibitor, is a c-glycosylated flavone that has been identified in medicinal plants. Therefore, we hypothesized that treatment with vitexin would protect against HI brain injury. Newborn rat pups were subjected to unilateral carotid artery ligation followed by 2.5 h of hypoxia (8% O2 at 37 °C). Vitexin (30, 45 or 60 mg/kg) was administered intraperitoneally at 5 min or 3 h after HI. Vitexin, administered 5 min after HI, was neuroprotective as seen by decreased infarct volume evaluated at 48 h post-HI. This neuroprotection was removed when vitexin was administered 3 h after HI. Neuronal cell death, blood-brain barrier (BBB) integrity, brain edema, HIF-1α and VEGF protein levels were evaluated using a combination of Nissl staining, IgG staining, brain water content, immunohistochemistry and Western blot at 24 and 48 h after HI. The long-term effects of vitexin were evaluated by brain atrophy measurement, Nissl staining and neurobehavioral tests. Vitexin (45 mg/kg) ameliorated brain edema, BBB disruption and neuronal cell death; Upregulation of HIF-1α by dimethyloxalylglycine (DMOG) increased the BBB permeability and brain edema compared to HI alone. Vitexin attenuated the increase in HIF-1α and VEGF. Vitexin also had long-term effects of protecting against the loss of ipsilateral brain and improveing neurobehavioral outcomes. In conclusion, our data indicate early HIF-1α inhibition with vitexin provides both acute and long-term neuroprotection in the developing brain after neonatal HI injury.

A Systems Biology Perspective on the Molecular Mechanisms Underlying the Therapeutic Effects of Buyang Huanwu Decoction on Ischemic Stroke

Ischemic stroke is the leading cause of adult disability worldwide. The outcome is worse in older patients, especially in terms of disability. Buyang Huanwu decoction (BHD), a famous traditional Chinese medicine formula, has been used extensively in the treatment of ischemic stroke for centuries. However, its pharmacological mechanisms have not been fully elucidated. In this study, 82 putative targets for 411 composite compounds contained in BHD were predicted on the basis of our previously developed target prediction system. On the basis of large-scale molecular docking, more than 80% compound-putative target pairs had medium to strong binding efficiency. The pharmacological networks of BHD were built according to relationships among herbs, putative targets, and known therapeutic targets for ischemic stroke, and 121 major nodes were identified by calculating three topological features-degree, node betweenness, and closeness. Importantly, the pathway enrichment analysis identified several signaling pathways involved with major putative targets of BHD, such as the calcium signaling pathway, vascular smooth muscle contraction, and nucleotide-binding oligomerization domain (NOD)-like receptor signaling pathway, which have not hitherto been reported. These data are expected to help find new therapeutic effects of BHD and optimize clinical use of this formula. Collectively, our study developed a comprehensive systems approach integrating drug target prediction and network and functional analyses to reveal the relationships of the herbs in BHD with their putative targets, and for the first time with ischemic stroke-related pathway systems. This is a pilot study based on bioinformatics analysis; thus, further experimental studies are required to validate our findings.