Peroxiredoxin 1-mediated activation of TLR4/NF-κB pathway contributes to neuroinflammatory injury in intracerebral hemorrhage

Molecular characterization, cytoprotective, DNA protective, and immunological assessment of peroxiredoxin-1 (Prdx1) from yellowtail clownfish (Amphiprion clarkii)

Peroxiredoxin-1 (Prdx1) is a thiol-specific antioxidant enzyme that detoxifies reactive oxygen species (ROS) and regulates the redox status of cells. In this study, the Prdx1 cDNA sequence was isolated from the pre-established Amphiprion clarkii (A. clarkii) (AcPrdx1) transcriptome database and characterized structurally and functionally. The AcPrdx1 coding sequence comprises 597 bp and encodes 198 amino acids with a molecular weight of 22.1 kDa and a predicted theoretical isoelectric point of 6.3. AcPrdx1 is localized and functionally available in the cytoplasm and nucleus of cells. The TXN domain of AcPrdx1 comprises two peroxiredoxin signature VCP motifs, which contain catalytic peroxidatic (Cp-C52) and resolving cysteine (CR-C173) residues. The constructed phylogenetic tree and sequence alignment revealed that AcPrdx1 is evolutionarily conserved, and its most closely related counterpart is Amphiprion ocellaris. Under normal physiological conditions, AcPrdx1 was ubiquitously detected in all tissues examined, with the most robust expression in the spleen. Furthermore, AcPrdx1 transcripts were significantly upregulated in the spleen, head kidney, and blood after immune stimulation by polyinosinic:polycytidylic acid (poly (I:C)), lipopolysaccharide (LPS), and Vibrio harveyi injection. Recombinant AcPrdx1 (rAcPrdx1) demonstrated antioxidant and DNA protective properties in a concentration-dependent manner, as evidenced by insulin disulfide reduction, peroxidase activity, and metal-catalyzed oxidation (MCO) assays, whereas cells transfected with pcDNA3.1(+)/AcPrdx1 showed significant cytoprotective function under oxidative and nitrosative stress. Overexpression of AcPrdx1 in fathead minnow (FHM) cells led to a lower viral copy number following viral hemorrhagic septicemia virus (VHSV) infection, along with upregulation of several antiviral genes. Collectively, this study provides insights into the function of AcPrdx1 in defense against oxidative stressors and its role in the immune response against pathogenic infections in A. clarkii.

Peroxiredoxin II exerts neuroprotective effects by inhibiting endoplasmic reticulum stress and oxidative stress-induced neuronal pyroptosis

BACKGROUND

Intracerebral hemorrhage (ICH) is a critical neurological condition with few treatment options, where secondary immune responses and specific cell death forms, like pyroptosis, worsen brain damage. Pyroptosis involves gasdermin-mediated membrane pores, increasing inflammation and neural harm, with the NLRP3/Caspase-1/GSDMD pathway being central to this process. Peroxiredoxin II (Prx II), recognized for its mitochondrial protection and reactive oxygen species (ROS) scavenging abilities, appears as a promising neuronal pyroptosis modulator. However, its exact role and action mechanisms need clearer definition. This research aims to explore Prx II impact on neuronal pyroptosis and elucidate its mechanisms, especially regarding endoplasmic reticulum (ER) stress and oxidative stress-induced neuronal damage modulation.

METHODS AND RESULTS

Utilizing MTT assays, Microscopy, Hoechst/PI staining, Western blotting, and immunofluorescence, we found Prx II effectively reduces LPS/ATP-induced pyroptosis and neuroinflammation in HT22 hippocampal neuronal cells. Our results indicate Prx II's neuroprotective actions are mediated through PI3K/AKT activation and ER stress pathway inhibition, diminishing mitochondrial dysfunction and decreasing neuronal pyroptosis through the ROS/MAPK/NF-κB pathway. These findings highlight Prx II potential therapeutic value in improving intracerebral hemorrhage outcomes by lessening secondary brain injury via critical signaling pathway modulation involved in neuronal pyroptosis.

CONCLUSIONS

Our study not only underlines Prx II importance in neuroprotection but also opens new therapeutic intervention avenues in intracerebral hemorrhage, stressing the complex interplay between redox regulation, ER stress, and mitochondrial dynamics in neuroinflammation and cell death management.

Geniposide ameliorates brain injury in mice with intracerebral hemorrhage by inhibiting NF-κB signaling

BACKGROUND

Neuroinflammation and oxidative stress are critical players in intracerebral hemorrhage (ICH). Geniposide is an active component of Gardenia that has anti-inflammatory effects. This study focused on the roles and mechanisms of geniposide in ICH.

METHODS

ICH was established by injecting collagenase IV into C57BL/6 mice. To determine the functions of geniposide and NF-κB inhibition in ICH model mice, geniposide (1, 25, or 50 mg/kg) or PDTC (a NF-κB inhibitor) was administered. Neurological functions were assessed with the modified neurological severity score (mNSS) test. Hematoxylin and eosin staining were performed to identify pathological changes. IL-1β and TNF-α levels were estimated with ELISA kits. NF-κB p65 localization was determined by immunofluorescence staining. Oxidative stress was analyzed by measuring ROS levels.

RESULTS

Geniposide alleviated cerebral edema and neurological deficits. Geniposide inhibited neuroinflammation and oxidative stress after ICH, and the inhibitory effects were enhanced by NF-κB inhibition. Additionally, geniposide inhibited NF-κB signaling.

CONCLUSION

Geniposide alleviates brain injury by suppressing inflammation and oxidative stress damage in experimental ICH models by inhibiting NF-κB signaling.

Deubiquitylating Enzyme OTUB1 Facilitates Neuronal Survival After Intracerebral Hemorrhage Via Inhibiting NF-κB-triggered Apoptotic Cascades

The deubiquitylase OTU domain-containing ubiquitin aldehyde-binding protein 1 (OTUB1) has been implicated in the pathogenesis of various human diseases. However, the molecular mechanism by which OTUB1 participates in the pathogenesis of intracerebral hemorrhage (ICH) remains elusive. In the present study, we established an autologous whole blood fusion-induced ICH model in C57BL/6 J mice. We showed that the upregulation of OTUB1 contributes to the attenuation of Nuclear factor kappa B (NF-κB) and its downstream apoptotic signaling after ICH. OTUB1 directly associates with NF-κB precursors p105 and p100 after ICH, leading to attenuated polyubiquitylation of p105 and p100. Moreover, we revealed that NF-κB signaling was modestly activated both in ICH tissues and hemin-exposed HT-22 neuronal cells, accompanied with the activation of NF-κB downstream pro-apoptotic signaling. Notably, overexpression of OTUB1 strongly inhibited hemin-induced NF-κB activation, whereas interference of OTUB1 led to the opposite effect. Finally, we revealed that lentiviral transduction of OTUB1 markedly ameliorated hemin-induced apoptotic signaling and HT-22 neuronal death. Collectively, these findings suggest that the upregulation of OTUB1 serves as a neuroprotective mechanism in antagonizing neuroinflammation-induced NF-κB signaling and neuronal death, shed new light on manipulating intracellular deubiquitylating pathways as novel interventive approaches against ICH-induced secondary neuronal damage and death.

Hepatocytes-derived Prdx1 regulates macrophage phenotypes via TLR4 activation in acute liver injury

Acute liver injury (ALI) is a significant causative factor for multiple hepatic diseases. The excessive inflammatory response triggers proinflammatory immune cells recruitment, infiltration and differentiation, further contributing to inflammatory injuries in liver. As a proinflammatory factor, circulating Peroxiredoxin 1 (Prdx1) is elevated in ALI patients and mice. In this study, through carbon tetrachloride (CCl4) and cecal puncture and ligation (CLP)-induced liver injury mice model, we found hepatocytes-derived Prdx1 expression was increased in ALI. After AAV8-Prdx1-mediated Prdx1 knockdown, CCl4 and CLP-induced ALI was alleviated, along with the reduced proinflammatory cytokines, suppressed myeloid cells recruitment, decreased proportions of hepatic macrophages and neutrophils, restrained proinflammatory macrophage differentiation and infiltration. Mechanistically, hepatocyte-derived Prdx1 regulated macrophages through paracrine activation of the TLR4 signal. Our data support the immune and inflammatory regulatory role of Prdx1 in ALI pathological process to suggest its potential therapeutic application and clinical value.

TDP43/HDAC6/Prdx1 signaling pathway participated in the cognitive impairment of obstructive sleep apnea via regulating inflammation and oxidative stress

Neuroinflammation and oxidative stress induced by intermittent hypoxia (IH) are associated with cognitive dysfunction in patients with obstructive sleep apnea (OSA). Recently, TAR DNA-binding protein 43 (TDP-43), histone deacetylase 6 (HDAC6), and peroxiredoxin 1 (Prdx1) have been reported to be involved in cognitive impairment in many degenerative diseases; however, the underlying mechanisms remain unclear. In the present study, subjects underwent polysomnography to diagnose OSA. Cognitive function was evaluated using the Montreal Cognitive Assessment (MoCA) and peripheral blood samples were collected. HMC3 cells were treated with lipopolysaccharide (LPS) to mimic in vitro neuroinflammation. Western blotting was used to assess protein expression and ELISA to assess inflammation and oxidative stress levels. Participants were divided into three groups: healthy control (n = 20); mild to moderate OSA (n = 20); and severe OSA (n = 20). The MoCA scores in mild-moderate OSA and severe OSA were lower than those in healthy controls. Continuous positive airway pressure therapy was found to be effective for cognitive impairment in subjects with severe OSA (24.70 ± 1.81). Expression of TDP-43 and HDAC6 was increased in subjects with OSA, whereas Prdx1 expression was decreased. Alterations in these proteins were partially reversed after 12 weeks of CPAP treatment. Protein expression of TDP-43 and HDAC6 was negatively correlated with MoCA scores in patients with OSA, while Prdx1 expression exhibited the opposite trend. In LPS-treated HMC3 cells, TDP-43 and HDAC6 were upregulated, whereas Prdx1 expression was reduced. TDP-43 influenced the expression of Prdx1 by regulating HDAC6, and inflammation and oxidative stress varied with the expression of TDP-43. When a specific inhibitor of HDAC6 was used, LPS-induced inflammation and oxidative stress were alleviated by an elevated level of Prdx1. In summary, findings of the present study suggest that TDP-43 influenced Prdx1 by regulating HDAC6 expression and promoting neuroinflammation and oxidative stress. This process may be involved in the cognitive impairment experienced by patients with OSA and may provide potential therapeutic targets.

Proteomics of the astrocyte secretome reveals changes in their response to soluble oligomeric Aβ

Astrocytes associate with amyloid plaques in Alzheimer's disease (AD). Astrocytes react to changes in the brain environment, including increasing concentrations of amyloid-β (Aβ). However, the precise response of astrocytes to soluble small Aβ oligomers at concentrations similar to those present in the human brain has not been addressed. In this study, we exposed astrocytes to media from neurons that express the human amyloid precursor protein (APP) transgene with the double Swedish mutation (APPSwe), and which contains APP-derived fragments, including soluble human Aβ oligomers. We then used proteomics to investigate changes in the astrocyte secretome. Our data show dysregulated secretion of astrocytic proteins involved in the extracellular matrix and cytoskeletal organization and increase secretion of proteins involved in oxidative stress responses and those with chaperone activity. Several of these proteins have been identified in previous transcriptomic and proteomic studies using brain tissue from human AD and cerebrospinal fluid (CSF). Our work highlights the relevance of studying astrocyte secretion to understand the brain response to AD pathology and the potential use of these proteins as biomarkers for the disease.

Peroxiredoxin-4 supplementation modulates the immune response, shapes the intestinal microbiome, and enhances AHPND resistance in Penaeus vannamei

Peroxiredoxin-4 from Penaeus vannamei (LvPrx4) is considered a damage-associated molecular pattern (DAMP) that can activate the expression of immune-related genes through the Toll pathway. We previously demonstrated that the recombinant LvPrx4 (rLvPrx4) can enhance shrimp resistance against Vibrio parahaemolyticus, causing acute hepatopancreatic necrosis disease (VP_AHPND), which causes great production losses in shrimp farming. Herein, we showed that the rLvPrx4 had a thermal tolerance of around 60 °C and that the ionic strength had no noticeable effect on its activity. We discovered that feeding a diet containing rLvPrx4 to shrimp for three weeks increased the expression of the immune-related genes LvPEN4 and LvVago5. Furthermore, pre-treatment with rLvPrx4 feeding could significantly prolong shrimp survival following the VP_AHPND challenge. The shrimp intestinal microbiome was then characterized using PCR amplification of the 16S rRNA gene and Illumina sequencing. Three weeks of rLvPrx4 supplementation altered the bacterial community structure (beta diversity) and revealed the induction of differentially abundant families, including Cryomorphaceae, Flavobacteriaceae, Pirellulaceae, Rhodobacteraceae, and Verrucomicrobiaceae, in the rLvPrx4 group. Metagenomic predictions indicated that some amino acid metabolism pathways, such as arginine and proline metabolism, and genetic information processing were significantly elevated in the rLvPrx4 group compared to the control group. This study is the first to describe the potential use of rLvPrx4 supplementation to enhance shrimp resistance to VP_AHPND and alter the composition of a beneficial bacterial community in shrimp, making rLvPrx4 a promising feed supplement as an alternative to antibiotics for controlling VP_AHPND infection in shrimp aquaculture.

Toll-like receptors (TLR2 and TLR4) antagonist mitigates the onset of cerebral small vessel disease through PI3K/Akt/GSK3β pathway in stroke-prone renovascular hypertensive rats

To examine the effect and mechanism of Toll-Like Receptors (TLR2, TLR4) antagonist in CSVD. The rat model of stroke-induced renovascular hypertension (RHRSP) was constructed. TLR2 and TLR4 antagonist was administrated by Intracranial injection. Morris water maze was used to observe the behavioral changes of rat models. HE staining, TUNEL staining and Evens Blue staining were performed to evaluate the permeability of the blood-brain barrier (BBB) and examine the CSVD occurrence and neuronal apoptosis. The inflammation and oxidative stress factors were detected by ELISA. Hypoxia-glucose-deficiency (OGD) ischemia model was constructed in cultured neurons. Western blot and ELISA were used to examine the related protein expression in TLR2/TLR4 signaling pathway and PI3K/Akt/GSK3β signaling pathway. The RHRSP rat model was successfully constructed, and the blood well and BBB permeability were altered. The RHRSP rats showed cogitative impairment and excessive immune response. After TLR2/TLR4 antagonist administration, the behavior of model rats were improved, cerebral white matter injury was reduced, and the expression of several key inflammatory factors including TLR4, TLR2, Myd88 and NF-kB were decreased, as well as the ICAM-1, VCAM-1, inflammation and oxidative stress factors. In vitro experiments showed that TLR4 and TLR2 antagonist increased the cell viability, inhibited the apoptosis, and decreased p-Akt and p-GSK3β expression. Moreover, the PI3K inhibitors resulted in decreased anti-apoptotic and anti-inflammatory effects of TLR4 and TLR2 antagonist. These results suggested that TLR4 and TLR2 antagonist achieved protective effect on the RHRSP through the PI3K/Akt/GSK3β pathway.

Molecular characterization, immune expression, and functional delineation of peroxiredoxin 1 in Epinephelus akaara

Peroxiredoxin 1 is a member of the typical 2-Cys peroxiredoxin family, which serves diverse functions in gene expression, immune and inflammatory responses, and tumor progression. In this study, we aimed to analyze the structural, functional, and immunomodulatory properties of peroxiredoxin 1 from Epinephelus akaara (EaPrx1). The open reading frame of EaPrx1 is 597 base pairs in length, encoding 198 amino acids, with a molecular weight of approximately 22 kDa. The in silico analysis revealed that EaPrx1 shares a conserved thioredoxin fold and signature motifs that are critical for its catalytic activity and oligomerization. Further, EaPrx1 is closely related to Epinephelus lanceolatus Prx1 and clustered in the Fishes group of the vertebrate clade, revealing that EaPrx1 was conserved throughout evolution. In terms of tissue distribution, a high level of EaPrx1 expression was observed in the spleen, brain, and blood tissues. Likewise, in immune challenge experiments, significant transcriptional modulations of EaPrx1 upon lipopolysaccharide, polyinosinic:polycytidylic acid, and nervous necrosis virus injections were noted at different time points, indicating the immunological role of EaPrx1 against pathogenic infections. In the functional analysis, rEaPrx1 exhibited substantial DNA protection, insulin disulfide reduction, and tissue repair activities, which were concentration-dependent. EaPrx1/pcDNA™ 3.1 (+)-transfected fathead minnow cells revealed high cell viability upon arsenic toxicity, indicating the heavy metal detoxification activity of EaPrx1. Taken together, the transcriptional and functional studies imply critical roles of EaPrx1 in innate immunity, redox regulation, apoptosis, and tissue-repair processes in E. akaara.

Neuroinflammation of microglia polarization in intracerebral hemorrhage and its potential targets for intervention

Microglia are the resident immune cells of the central nervous system (CNS) and play a key role in neurological diseases, including intracerebral hemorrhage (ICH). Microglia are activated to acquire either pro-inflammatory or anti-inflammatory phenotypes. After the onset of ICH, pro-inflammatory mediators produced by microglia at the early stages serve as a crucial character in neuroinflammation. Conversely, switching the microglial shift to an anti-inflammatory phenotype could alleviate inflammatory response and incite recovery. This review will elucidate the dynamic profiles of microglia phenotypes and their available shift following ICH. This study can facilitate an understanding of the self-regulatory functions of the immune system involving the shift of microglia phenotypes in ICH. Moreover, suggestions for future preclinical and clinical research and potential intervention strategies are discussed.

The dual function of microglial polarization and its treatment targets in ischemic stroke

Stroke is the leading cause of disability and death worldwide, with ischemic stroke occurring in ~5% of the global population every year. Recently, many studies have been conducted on the inflammatory response after stroke. Microglial/macrophage polarization has a dual function and is critical to the pathology of ischemic stroke. Microglial/macrophage activation is important in reducing neuronal apoptosis, enhancing neurogenesis, and promoting functional recovery after ischemic stroke. In this review, we investigate the physiological characteristics and functions of microglia in the brain, the activation and phenotypic polarization of microglia and macrophages after stroke, the signaling mechanisms of polarization states, and the contribution of microglia to brain pathology and repair. We summarize recent advances in stroke-related microglia research, highlighting breakthroughs in therapeutic strategies for microglial responses after stroke, thereby providing new ideas for the treatment of ischemic stroke.

AQP2 Promotes Astrocyte Activation by Modulating the TLR4/NFκB-p65 Pathway Following Intracerebral Hemorrhage

Microglial and astrocyte activation and related cytokine secretion play key roles in secondary brain injury following intracerebral hemorrhage (ICH). We assessed the role of aquaporin (AQP)2 in immune response after ICH. We prospectively collected data from 33 patients with ICH and analyzed the serum AQP2 levels in these patients and age-matched healthy controls. A correlation analysis was also performed between patient serum AQP2 levels and clinical factors. In the rat ICH model, double-fluorescence staining for glial fibrillary acidic protein (GFAP) and AQP2 was performed to investigate the relationship between astrocytes and AQP2. Relative mRNA expression levels of GFAP and AQP2 were also measured. In the rat astrocyte cell line CTX-TNA2, toll-like receptor (TLR)4/nuclear factor kappa B (NFκB)-p65 pathway activation and GFAP levels were measured. The indirect influence of AQP2 on microglial polarization was assessed following exposure to the medium of astrocytes treated with AQP2-overexpression plasmid or silencing RNA. We found that the serum AQP2 expression was lower in patients with ICH. Sex and blood neutrophil count influenced serum AQP2 concentrations in patients with ICH on admission. Lower serum AQP2 levels were inversely correlated with 90-day Modified Rankin Scale scores after ICH, but were not correlated with National Institute of Health stroke scale (NIHSS) scores on admission. AQP2 overexpression and localization in GFAP-labeled astrocytes were observed in rats. AQP2 overexpression induced astrocyte activation with GFAP upregulation via TLR/NFκB-p65 signaling pathway activation in the rat astrocyte cell line CTX-TNA2. Astrocyte activation promoted interleukin-1β secretion. The medium of AQP2-overexpression astrocytes promoted the pro-inflammatory M1 phenotype in the immortal rat (HAPI) microglial cell line. Therefore, serum AQP2 is negatively correlated with post-ICH prognosis and may be a marker of inflammation in early-stage ICH. AQP2 overexpression promotes astrocyte activation and pro-inflammatory secretion, affects astrocyte-microglia crosstalk, and indirectly induces microglial polarization, which may augment inflammation after ICH.

Anti-Inflammatory Activity of Bryophytes Extracts in LPS-Stimulated RAW264.7 Murine Macrophages

Bryophytes produce rare and bioactive compounds with a broad range of therapeutic potential, and many species are reported in ethnomedicinal uses. However, only a few studies have investigated their potential as natural anti-inflammatory drug candidate compounds. The present study investigates the anti-inflammatory effects of thirty-two species of bryophytes, including mosses and liverworts, on Raw 264.7 murine macrophages stimulated with lipopolysaccharide (LPS) or recombinant human peroxiredoxin (hPrx1). The 70% ethanol extracts of bryophytes were screened for their potential to reduce the production of nitric oxide (NO), an important pro-inflammatory mediator. Among the analyzed extracts, two moss species significantly inhibited LPS-induced NO production without cytotoxic effects. The bioactive extracts of Dicranum majus and Thuidium delicatulum inhibited NO production in a concentration-dependent manner with IC₅₀ values of 1.04 and 1.54 µg/mL, respectively. The crude 70% ethanol and ethyl acetate extracts were then partitioned with different solvents in increasing order of polarity (n-hexane, diethyl ether, chloroform, ethyl acetate, and n-butanol). The fractions were screened for their inhibitory effects on NO production stimulated with LPS at 1 ng/mL or 10 ng/mL. The NO production levels were significantly affected by the fractions of decreasing polarity such as n-hexane and diethyl ether ones. Therefore, the potential of these extracts to inhibit the LPS-induced NO pathway suggests their effective properties in attenuating inflammation and could represent a perspective for the development of innovative therapeutic agents.

TNF-α induces AQP4 overexpression in astrocytes through the NF-κB pathway causing cellular edema and apoptosis

Aquaporin 4 (AQP4) is highly expressed on astrocytes and is critical for controlling brain water transport in neurological diseases. Tumor necrosis factor (TNF)-α is a common cytokine found in disease microenvironment. The aim of this study was to determine whether TNF-α can regulate the expression of AQP4 in astrocytes. Primary astrocyte cultures were treated with different concentrations of TNF-α and the cell viability was assessed through cell counting kit-8 assay and AQP4 expression was detected by qPCR, western blots, and immunofluorescence assays. The activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway was detected by western blot. Further, dual-luciferase reporting system and chromatin immunoprecipitation were used to detect the transcriptional regulation of AQP4 by p65. These experiments demonstrated that treatment with TNF-α can lead to astrocyte edema and an increase in AQP4 expression. Following TNF-α treatment, the expression levels of P-IKKα/β-IκBα and P-p65 increased significantly over time. The results of the dual-luciferase reporter system and chromatin immunoprecipitation assays revealed that p65 protein and AQP4 promoter had a robust binding effect after TNF-α treatment, and the NF-κB pathway inhibitor, BAY 11-7082 could inhibit these effects of TNF-α. The expression level of AQP4 was significantly decreased upon p65 interference, while the astrocyte viability was significantly increased compared to that in the TNF-α only group. In conclusion, TNF-α activated NF-κB pathway, which promoted the binding of p65 to the AQP4 gene promoter region, and enhanced AQP4 expression, ultimately reducing astrocyte viability and causing cell edema.

Atorvastatin suppresses NLRP3 inflammasome activation in intracerebral hemorrhage via TLR4- and MyD88-dependent pathways

Intracerebral hemorrhage (ICH) is a common neurological condition that causes severe disability and even death. Even though the mechanism is not clear, increasing evidence shows the efficacy of atorvastatin on treating ICH. In this study, we examined the impact of atorvastatin on the NOD-like receptor protein 3 (NLRP3) inflammasome and inflammatory pathways following ICH. Mouse models of ICH were established by collagenase injection in adult C57BL/6 mice. IHC mice received atorvastatin treatment 2 h after hematoma establishment. First, the changes of glial cells and neurons in the brains of ICH patients and mice were detected by immunohistochemistry and western blotting. Second, the molecular mechanisms underlying the microglial activation and neuronal loss were evaluated after the application of atorvastatin. Finally, the behavioral deficits of ICH mice without or with the treatment of atorvastatin were determined by neurological defect scores. The results demonstrated that atorvastatin significantly deactivated glial cells by reducing the expression of glial fibrillary acidic protein (GFAP), Ionized calcium binding adapter molecule 1 (Iba1), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 in ICH model mice. For inflammasomes, atorvastatin also showed its efficacy by decreasing the expression of NLRP3, cleaved caspase-1, and IL-1β in ICH mice. Moreover, atorvastatin markedly inhibited the upregulation of toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 (MyD88), which indicated deactivation of NLRP3 inflammasomes. By inhibiting the activities of inflammasomes in glial cells, neuronal loss was partially prevented by suppressing the apoptosis in the brains of ICH mice, protecting them from neurological defects.

The Role of Peroxiredoxins in the Regulation of Sepsis

Oxidative stress, a result of a disturbance in redox homeostasis, is considered to be one of the main aggravating events in the pathogenesis of immune disorders. Peroxiredoxins (Prdxs) are an enzyme family that catalyzes the reduction of peroxides, including hydrogen peroxide, lipid peroxides, and nitrogen peroxides. Although the maintenance of cellular redox homeostasis through Prdxs is essential for surviving in adverse environments, Prdxs also participate in the regulation of cellular signal transduction by modulating the activities of a panel of molecules involved in the signal transduction process. Although Prdxs were discovered as intracellular anti-oxidative enzymes, recent research has revealed that Prdxs also play important roles in the extracellular milieu. Indeed, Prdxs have been shown to have the capacity to activate immune cells through ligation with innate immune receptors such as toll-like receptors (TLRs). In this review, we will summarize the intracellular as well as extracellular roles of Prdxs for and against the pathogenesis of inflammatory disorders including sepsis, hemorrhagic shock, and drug-induced liver injury.

SK-Channel Activation Alters Peripheral Metabolic Pathways in Mice, but Not Lipopolysaccharide-Induced Fever or Inflammation

Purpose

Previously, we have shown that CyPPA (cyclohexyl-[2-(3,5-dimethyl-pyrazol-1-yl)-6-methyl-pyrimidin-4-yl]-amine), a pharmacological small-conductance calcium-activated potassium (SK)–channel positive modulator, antagonizes lipopolysaccharide (LPS)-induced cytokine expression in microglial cells. Here, we aimed to test its therapeutic potential for brain-controlled sickness symptoms, brain inflammatory response during LPS-induced systemic inflammation, and peripheral metabolic pathways in mice.

Methods

Mice were pretreated with CyPPA (15 mg/kg IP) 24 hours before and simultaneously with LPS stimulation (2.5 mg/kg IP), and the sickness response was recorded by a telemetric system for 24 hours. A second cohort of mice were euthanized 2 hours after CyPPA or solvent treatment to assess underlying CyPPA-induced mechanisms. Brain, blood, and liver samples were analyzed for inflammatory mediators or nucleotide concentrations using immunohistochemistry, real-time PCR and Western blot, or HPLC. Moreover, we investigated CyPPA-induced changes of UCP1 expression in brown adipose tissue (BAT)–explant cultures.

Results

CyPPA treatment did not affect LPS-induced fever, anorexia, adipsia, or expression profiles of inflammatory mediators in the hypothalamus or plasma or microglial reactivity to LPS (CD11b staining and CD68 mRNA expression). However, CyPPA alone induced a rise in core body temperature linked to heat production via altered metabolic pathways like reduced levels of adenosine, increased protein content, and increased UCP1 expression in BAT-explant cultures, but no alteration in ATP/ADP concentrations in the liver. CyPPA treatment was accompanied by altered pathways, including NFκB signaling, in the hypothalamus and cortex, while circulating cytokines remained unaltered.

Conclusion

Overall, while CyPPA has promise as a treatment strategy, in particular according to results from in vitro experiments, we did not reveal anti-inflammatory effects during severe LPS-induced systemic inflammation. Interestingly, we found that CyPPA alters metabolic pathways inducing short hyperthermia, most likely due to increased energy turnover in the liver and heat production in BAT.

De novo assembly and functional annotation of blood transcriptome of loggerhead turtle, and in silico characterization of peroxiredoxins and thioredoxins

The aim of this study was to generate and analyze the atlas of the loggerhead turtle blood transcriptome by RNA-seq, as well as identify and characterize thioredoxin (Tnxs) and peroxiredoxin (Prdxs) antioxidant enzymes of the greatest interest in the control of peroxide levels and other biological functions. The transcriptome of loggerhead turtle was sequenced using the Illumina Hiseq 2000 platform and de novo assembly was performed using the Trinity pipeline. The assembly comprised 515,597 contigs with an N50 of 2,631 bp. Contigs were analyzed with CD-Hit obtaining 374,545 unigenes, of which 165,676 had ORFs encoding putative proteins longer than 100 amino acids. A total of 52,147 (31.5%) of these transcripts had significant homology matches in at least one of the five databases used. From the enrichment of GO terms, 180 proteins with antioxidant activity were identified, among these 28 Prdxs and 50 putative Tnxs. The putative proteins of loggerhead turtles encoded by the genes Prdx1, Prdx3, Prdx5, Prdx6, Txn and Txnip were predicted and characterized in silico. When comparing Prdxs and Txns of loggerhead turtle with homologous human proteins, they showed 18 (9%), 52 (18%) 94 (43%), 36 (16%), 35 (33%) and 74 (19%) amino acid mutations respectively. However, they showed high conservation in active sites and structural motifs (98%), with few specific modifications. Of these, Prdx1, Prdx3, Prdx5, Prdx6, Txn and Txnip presented 0, 25, 18, three, six and two deleterious changes. This study provides a high quality blood transcriptome and functional annotation of loggerhead sea turtles.

Identification of key genes and pathways associated with resting mast cells in meningioma

BACKGROUND

To identify candidate key genes and pathways related to resting mast cells in meningioma and the underlying molecular mechanisms of meningioma.

METHODS

Gene expression profiles of the used microarray datasets were obtained from the Gene Expression Omnibus (GEO) database. GO and KEGG pathway enrichments of DEGs were analyzed using the ClusterProfiler package in R. The protein-protein interaction network (PPI), and TF-miRNA- mRNA co-expression networks were constructed. Further, the difference in immune infiltration was investigated using the CIBERSORT algorithm.

RESULTS

A total of 1499 DEGs were identified between tumor and normal controls. The analysis of the immune cell infiltration landscape showed that the probability of distribution of memory B cells, regulatory T cells (Tregs), and resting mast cells in tumor samples were significantly higher than those in the controls. Moreover, through WGCNA analysis, the module related to resting mast cells contained 158 DEGs, and KEGG pathway analysis revealed that the DEGs were dominant in the TNF signaling pathway, cytokine-cytokine receptor interaction, and IL-17 signaling pathway. Survival analysis of hub genes related to resting mast cells showed that the risk model was constructed based on 9 key genes. The TF-miRNA- mRNA co-regulation network, including MYC-miR-145-5p, TNFAIP3-miR-29c-3p, and TNFAIP3-hsa-miR-335-3p, were obtained. Further, 36 nodes and 197 interactions in the PPI network were identified.

CONCLUSION

The results of this study revealed candidate key genes, miRNAs, and pathways related to resting mast cells involved in meningioma development, providing potential therapeutic targets for meningioma treatment.

Microglia Phenotype and Intracerebral Hemorrhage: A Balance of Yin and Yang

Intracerebral hemorrhage (ICH) features extremely high rates of morbidity and mortality, with no specific and effective therapy. And local inflammation caused by the over-activated immune cells seriously damages the recovery of neurological function after ICH. Fortunately, immune intervention to microglia has provided new methods and ideas for ICH treatment. Microglia, as the resident immune cells in the brain, play vital roles in both tissue damage and repair processes after ICH. The perihematomal activated microglia not only arouse acute inflammatory responses, oxidative stress, excitotoxicity, and cytotoxicity to cause neuron death, but also show another phenotype that inhibit inflammation, clear hematoma and promote tissue regeneration. The proportion of microglia phenotypes determines the progression of brain tissue damage or repair after ICH. Therefore, microglia may be a promising and imperative therapeutic target for ICH. In this review, we discuss the dual functions of microglia in the brain after an ICH from immunological perspective, elaborate on the activation mechanism of perihematomal microglia, and summarize related therapeutic drugs researches.

Tumor Necrosis Factor-stimulated Gene-6 (TSG-6) Secreted by BMSCs Regulates Activated Astrocytes by Inhibiting NF-κB Signaling Pathway to Ameliorate Blood Brain Barrier Damage After Intracerebral Hemorrhage

To investigate the influence of tumor necrosis factor-stimulated gene-6 (TSG-6) secreted by bone mesenchymal stem cells (BMSCs) on blood brain barrier (BBB) after intracerebral hemorrhage (ICH) and its related mechanisms. BMSCs and astrocytes were isolated and induced by TNF-α and LPS respectively. The effect of TSG-6 secreted by BMSCs on the proliferation and apoptosis of astrocytes and inflammatory response were assessed by CCK8, flow cytometry, and ELISA respectively. Then we studied the effects of TSG-6 secreted by BMSCs through the paracrine mechanism on the integrity of BBB after ICH via NF-κB signaling pathway in vitro and in vivo. We successfully isolated BMSCs and astrocytes. After LPS treatment of astrocytes, IL-1β, IL-6, and TNF-α showed an upward trend. TSG-6 secreted by TNF-α-activated BMSCs could antagonize the inflammatory response in activated astrocytes. Through the co-culture of astrocytes and BMSCs and the ICH animal model, we found that TSG-6 regulates activated astrocytes by inhibiting the NF-κB signaling pathway and ameliorates BBB damage. Furthermore, we found that TNF-α-activated BMSCs secreted exosomes containing TSG-6 and played an anti-inflammatory effect. TSG-6 secreted by BMSCs regulates activated astrocytes by inhibiting the NF-κB signaling pathway, thereby ameliorating BBB damage.

Peroxiredoxin 1 Controls Ovulation and Ovulated Cumulus-Oocyte Complex Activity through TLR4-Derived ERK1/2 Signaling in Mice

Peroxiredoxins (PRDXs) are expressed in the ovary and during ovulation. PRDX1 activity related to the immuno-like response during ovulation is unknown. We investigated the roles of Prdx1 on TLR4 and ERK1/2 signaling from the ovulated cumulus–oocyte complex (COC) using Prdx1-knockout (K/O) and wild-type (WT) mice. Ovulated COCs were collected 12 and 16 h after pregnant mare serum gonadotropin/hCG injection. PRDX1 protein expression and COC secretion factors (Il-6, Tnfaip6, and Ptgs2) increased 16 h after ovulated COCs of the WT mice were obtained. We treated the ovulated COCs in mice with LPS (0.5 μg/mL) or hyaluronidase (Hya) (10 units/mL) to induce TLR4 activity. Intracellular reactive oxygen species (ROS), cumulus cell apoptosis, PRDX1, TLR4/P38/ERK1/2 protein expression, and COC secretion factors’ mRNA levels increased in LPS- and Hya-treated COCs. The ERK inhibitor (U0126) and Prdx1 siRNA affected TLR4/ERK1/2 expression. The number and cumulus expansion of ovulated COCs by ROS were impaired in Prdx1 K/O mice but not in WT ones. Prdx1 gene deletion induced TLR4/P38/ERK1/2 expression and cumulus expansion genes. These results show the controlling roles of PRDX1 for TLR4/P38/ERK1/2 signaling activity in ovulated mice and the interlink of COCs with ovulation.

Phthalide derivative CD21 attenuates tissue plasminogen activator-induced hemorrhagic transformation in ischemic stroke by enhancing macrophage scavenger receptor 1-mediated DAMP (peroxiredoxin 1) clearance

BACKGROUND

Hemorrhagic transformation (HT) is a critical issue in thrombolytic therapy in acute ischemic stroke. Damage-associated molecular pattern (DAMP)-stimulated sterile neuroinflammation plays a crucial role in the development of thrombolysis-associated HT. Our previous study showed that the phthalide derivative CD21 attenuated neuroinflammation and brain injury in rodent models of ischemic stroke. The present study explored the effects and underlying mechanism of action of CD21 on tissue plasminogen activator (tPA)-induced HT in a mouse model of transient middle cerebral artery occlusion (tMCAO) and cultured primary microglial cells.

METHODS

The tMCAO model was induced by 2 h occlusion of the left middle cerebral artery with polylysine-coated sutures in wildtype (WT) mice and macrophage scavenger receptor 1 knockout (MSR1^-/-) mice. At the onset of reperfusion, tPA (10 mg/kg) was intravenously administered within 30 min, followed by an intravenous injection of CD21 (13.79 mg/kg/day). Neuropathological changes were detected in mice 3 days after surgery. The effect of CD21 on phagocytosis of the DAMP peroxiredoxin 1 (Prx1) in lysosomes was observed in cultured primary microglial cells from brain tissues of WT and MSR1^-/- mice.

RESULTS

Seventy-two hours after brain ischemia, CD21 significantly attenuated neurobehavioral dysfunction and infarct volume. The tPA-infused group exhibited more severe brain dysfunction and hemorrhage. Compared with tPA alone, combined treatment with tPA and CD21 significantly attenuated ischemic brain injury and hemorrhage. Combined treatment significantly decreased Evans blue extravasation, matrix metalloproteinase 9 expression and activity, extracellular Prx1 content, proinflammatory cytokine mRNA levels, glial cells, and Toll-like receptor 4 (TLR4)/nuclear factor κB (NF-κB) pathway activation and increased the expression of tight junction proteins (zonula occludens-1 and claudin-5), V-maf musculoaponeurotic fibrosarcoma oncogene homolog B, and MSR1. MSR1 knockout significantly abolished the protective effect of CD21 against tPA-induced HT in tMCAO mice. Moreover, the CD21-induced phagocytosis of Prx1 was MSR1-dependent in cultured primary microglial cells from WT and MSR1^-/- mice, respectively.

CONCLUSION

The phthalide derivative CD21 attenuated tPA-induced HT in acute ischemic stroke by promoting MSR1-induced DAMP (Prx1) clearance and inhibition of the TLR4/NF-κB pathway and neuroinflammation.

Microglia: A Double-Edged Sword in Intracerebral Hemorrhage From Basic Mechanisms to Clinical Research

Microglia are the resident immune cells of the central nervous system (CNS). It is well established that microglia are activated and polarized to acquire different inflammatory phenotypes, either pro-inflammatory or anti-inflammatory phenotypes, which act as a critical component in the neuroinflammation following intracerebral hemorrhage (ICH). Microglia produce pro-inflammatory mediators at the early stages after ICH onset, anti-inflammatory microglia with neuroprotective effects appear to be suppressed. Previous research found that driving microglia towards an anti-inflammatory phenotype could restrict inflammation and engulf cellular debris. The principal objective of this review is to analyze the phenotypes and dynamic profiles of microglia as well as their shift in functional response following ICH. The results may further the understanding of the body's self-regulatory functions involving microglia following ICH. On this basis, suggestions for future clinical development and research are provided.

Sivelestat-loaded nanostructured lipid carriers modulate oxidative and inflammatory stress in human dental pulp and mesenchymal stem cells subjected to oxygen-glucose deprivation

Stroke remains the leading cause of morbidity and mortality. Stem cell-based therapy offers promising hope for survivors and their families. Despite the clinical translation of stem cell-based therapies in stroke patients for almost two decades, results of these randomized controlled trials are not very optimistic. In these lines, an amalgamation of nanocarriers based drug delivery with stem cells holds great promise in enhancing stroke recovery. In the present study, we treated oxygen-glucose deprivation (OGD) exposed dental pulp stem cells (DPSCs) and mesenchymal stem cells (MSCs) with sivelestat-loaded nanostructured lipid carriers (NLCs). Various physicochemical limitations associated with sivelestat drug applications and its recent inefficacy in the clinical trials necessitates the development of novel delivery approaches for sivelestat. Therefore, to improve its efficacy on the survival of DPSCs and MSCs cell types under OGD insult, the current NLCs were formulated and characterized. Resulting NLCs exhibited a hydrodynamic diameter of 160-180 nm by DLS technique and possessed good PDI values of 0.2-0.3. Their shape, size and surface morphology were corroborated with microscopic techniques like TEM, SEM, and AFM. FTIR and UV-Vis techniques confirmed nanocarrier's loading capacity, encapsulation efficiency of sivelestat, and drug release profile. Oxidative stress in DPSCs and MSCs was assessed by DHE and DCFDA staining, and cell viability was assessed by Trypan blue exclusion test and MTT assay. Results indicated that sivelestat-loaded NLCs protected the loss of cell membrane integrity and restored cell morphology. Furthermore, NLCs successfully defended human DPSCs and MSCs against OGD-induced oxidative and inflammatory stress. In conclusion, modulation of oxidative and inflammatory stress by treatment with sivelestat-loaded NLCs in DPSCs and MSCs provides a novel strategy to rescue stem cells during ischemic stroke.

Mild hypothermia improves brain injury in rats with intracerebral hemorrhage by inhibiting IRAK2/NF-κB signaling pathway

OBJECTIVE

To explore the effect of mild hypothermia on nerve injury by establishing a rat model of intracerebral hemorrhage (ICH), and to clarify the specific molecular mechanism of mild hypothermia in improving brain injury in ICH rats.

METHODS

The rat model of ICH was established by collagenase injection. The neurological deficit score (NDS), brain tissue water detection, and Nissl staining were applied to detect the degree of brain injury. ELISA was used to analyze the expression of proinflammatory cytokines and serum nerve injury indexes. Flow cytometry and Western Blot were used to detect neuronal apoptosis.

RESULTS

Mild hypothermia treatment significantly improved the brain injury of the ICH rats and down-regulated the inflammatory response and oxidative stress in the brain tissue. Moreover, mild hypothermia also effectively inhibited IRAK2/NF-κB signaling pathway and thus affect neuronal apoptosis.

CONCLUSION

Mild hypothermia alleviates inflammatory response and neuronal apoptosis by inhibiting IRAK2/NF-κB signaling pathway in the ICH rats thus improving brain injury.

Phthalide derivative CD21 alleviates cerebral ischemia-induced neuroinflammation: Involvement of microglial M2 polarization via AMPK activation

Microglia can be activated to become the classic phenotype (M1) or alternative phenotype (M2), which play an important role in regulating neuroinflammatory response and tissue repair after ischemic stroke. CD21, a novel phthalide derivative, is a potential neuroprotectant against ischemic brain injury. The present study further investigated the effects of CD21 on post-ischemic microglial polarization and the underlying mechanisms. Transient middle cerebral artery occlusion (tMCAO) was used as a mouse model of ischemic stroke, while BV2 cells stimulated with conditioned medium collected from oxygen-glucose deprivation-treated HT22 cells were used in in vitro ischemic studies. The current results showed that CD21 dose-dependently and significantly improved neurological outcomes in tMCAO mice. Biochemical analyses revealed that CD21 decreased the expression of M1 phenotype markers (CD86, interleukin-1β and inducible nitric oxide synthase) and increased the expression of M2 phenotype markers (CD206, interleukin-10 and YM1/2) in both ischemic brain tissues and BV2 cells. Meanwhile, CD21 decreased the production of proinflammatory cytokines (interleukin-1β, interleukin-6 and tumor necrosis factor-α), promoted the release of the antiinflammatory cytokine (interleukin-10), and enhanced the phosphorylation of adenosine 5'-monophosphate-activated protein kinase (AMPK) in ischemic brain tissue and BV2 cells. Furthermore, the AMPK inhibitor (compound C) reversed these effects of CD21 in BV2 cells. These findings indicate that CD21 alleviates post-ischemic neuroinflammation through induction of microglial M2 polarization that is at least in part medicated by AMPK activation, suggesting that CD21 may be a promising candidate for protecting against ischemic brain injury.

Systematic Understanding of Mechanism of Yi-Qi-Huo-Xue Decoction Against Intracerebral Hemorrhagic Stroke Using a Network Pharmacology Approach

Background

Intracerebral hemorrhage (ICH), a fatal type of stroke, profoundly affects public health. Yi-Qi-Huo-Xue decoction (YQHXD), a traditional Chinese medicine (TCM) prescription, is verified to be an efficient method to treat ICH stroke among the Chinese population. Nevertheless, the pharmacological mechanisms of YQHXD have been unclear.

Material/Methods

We used a strategy based on network pharmacology to explore the possible multi-component, multi-target, and multi-pathway pattern of YQHXD in treating ICH. First, candidate targets for YQHXD were identified using the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP). Then, these candidate YQHXD targets were used in combination with the known targets for the treatment of ICH stroke to construct the core network (cPPI) using data on protein–protein interaction (PPI). We calculated 5 topological parameters for identification of the main hubs. Pathway enrichment and GO biological process enrichment analyses were performed after the incorporation of the main hubs into ClueGO.

Results

In total, 55 candidate YQHXD targets for ICH were recognized to be the major hubs in accordance with their topological importance. As suggested by enrichment analysis, the YQHXD targets for ICH were roughly classified into several biological processes (related to redox equilibrium, cell–cell communication, adhesion and collagen biosynthesis, cytokine generation, lymphocyte differentiation and activation, neurocyte apoptosis and development, neuroendocrine system, and vascular development) and related pathways (VEGF, mTOR, NF-kB, RAS/MAPK, JAK/STAT and cytokine–cytokine receptors interaction), indicating those mechanisms underlying the therapeutic effect of YQHXD.

Conclusions

The present results may serve as a pharmacological framework for TCM studies in the future, helping to promote the use of YQHXD in clinical treatment of ICH.

Ileal proteomic changes associated with IL-25-mediated resistance against intestinal trematode infections

Background

Echinostoma caproni (Trematoda: Echinostomatidae) is an intestinal trematode, which has been extensively used to investigate the factors that determine the rejection of intestinal helminths. In this sense, several studies have shown that IL-25 is critical for the development of resistance against E. caproni in mice. In fact, treatment of mice with recombinant IL-25 generates resistance against primary E. caproni infection. However, the mechanisms by which IL-25 induces resistance remain unknown.

Methods

To study the mechanisms responsible for resistance elicited by IL-25, we analyzed the ileal proteomic changes induced by IL-25 in mice and their potential role in resistance. To this purpose, we compared the protein expression profiles in the ileum of four experimental groups of mice: naïve controls; E. caproni-infected mice; rIL-25-treated mice; and rIL-25-treated mice exposed to E. caproni metacercariae.

Results

Quantitative comparison by 2D-DIGE showed significant changes in a total of 41 spots. Of these, 40 validated protein spots were identified by mass spectrometry corresponding to 24 proteins.

Conclusions

Our results indicate that resistance to infection is associated with the maintenance of the intestinal epithelial homeostasis and the regulation of proliferation and cell death. These results provide new insights into the proteins involved in the regulation of tissue homeostasis after intestinal infection and its transcendence in resistance.

Oxidative Stress Biomarkers in Erythrocytes of Captive Pre-Juvenile Loggerhead Turtles Following Acute Exposure to Methylmercury

This study describes the use of erythrocytes (RBCs) of loggerhead turtles as in vitro models for evaluating their toxicity to methylmercury. Blood samples of loggerhead turtles that were born in the Colombian Caribbean were used. The LC50 of RBCs to methylmercury was determined at 96 h using methylmercury concentrations of 0.5–100 mg L−1. Next, the viability of the RBCs and the activity of the enzymes superoxide dismutase (SOD), glutathione S-transferase (GST), and lipid peroxidation by malondialdehyde (MDA) at 6 and 12 h of exposure to acute concentrations of 0, 1, and 5 mg L−1 were evaluated. The LC50 for loggerhead turtle RBCs was 8.32 mg L−1. The cell viability bioassay of RBCs exposed for 12 h only showed 100% cell viability. Increasing in vitro MeHg concentrations caused a corresponding increase in MDA concentration as well as decreases in the activities of SOD and GST. The RBCs represent an excellent model for ecotoxicological studies and SOD, GST, and MDA are biomarkers of environmental pollution and oxidative stress in loggerhead turtles. This was the first study conducted on loggerhead turtle where the response of RBCs to MeHg-induced oxidative stress is evaluated.

Neuroprotective Effect of Phthalide Derivative CD21 against Ischemic Brain Injury:Involvement of MSR1 Mediated DAMP peroxiredoxin1 Clearance and TLR4 Signaling Inhibition

The macrophage scavenger receptor 1 (MSR1)-induced resolution of neuroinflammation may be a novel therapeutic strategy for ischemic stroke. Our previous study showed that the neuroprotective and anti-inflammatory effects of phthalide are associated with the inhibition of the post-ischemic damage-associated molecular pattern (DAMP)/Toll-like receptor 4 (TLR4) pathway. This study investigated the effects of the phthalide derivative CD21 on ischemic brain injury and the mechanism underlying MSR1-induced resolution of neuroinflammation. Using a rat model of 2 h transient middle cerebral artery occlusion (MCAO), MSR1-induced peroxiredoxin1 (PRX1) clearance in RAW264.7 macrophages were investigated. We show here that CD21 significantly ameliorated infarct volumes and neurological deficits in a dose-dependent manner with a ≥ 12 h therapeutic time window. Moreover, administration of 5 mg/kg/day CD21 over 24 h significantly reduced pathological damages, with associated inhibition of PRX1 expression, reduced TLR4/nuclear factor-κB activation and the suppression of the inflammatory response in MCAO rats. Furthermore, the expression of MAFB/MSR1 in the ischemic brain was elevated and the phagocytosis of PRX1 in CD68-positive macrophages isolated from the ischemic brain was enhanced. Further in vitro studies show that CD21 (20 μM) strongly enhanced the Msr1 mRNA and MSR1 protein levers in RAW264.7 cells and PRX1 internalization in cellular lysosomes, which were significantly reversed by N-acetylcysteine treatment. These results suggest that CD21 may exert neuroprotective and anti-inflammatory effects with a wide time window for the treatment of ischemic stroke. The anti-stroke effects of CD21 appear to be mediated partially via the induction of MSR1-promoted DAMP (PRX1) clearance, TLR4/nuclear factor-κB pathway inhibition, and the resolution of inflammation. Graphical Abstract The neuroprotective action of CD21 was associated with the resolution of neuroinflammation through enhancement of the MAFB-MSR1 pathway that leads to DAMP (PRX1) phagocytosis and TLR4 pathway inhibition. Red solid arrows represent promotion, red dotted arrow represents the positive correlation, green arrows represent inhibition.

Delayed PARP-1 Inhibition Alleviates Post-stroke Inflammation in Male Versus Female Mice: Differences and Similarities

Post-stroke inflammation is almost involved in the whole process of stroke pathogenesis, which serves as a prime target for developing new stroke therapies. Despite known sex differences in the incidence and outcome of stroke, few preclinical or clinical studies take into account sex bias in treatment. Recent evidence suggests that poly (ADP-ribose) polymerase (PARP)-1 inhibitor exerts sex-specific neuroprotection in the ischemic stroke. This study was aimed to investigate the effects of delayed PARP-1 inhibition on post-stroke inflammation and possible sexual dimorphism, and explore the possible relevant mediators. In male and female C57BL/6 mice subjected to transit middle cerebral artery occlusion (MCAO), we found that delayed treatment of PARP-1 inhibitor at 48 h following reperfusion could comparably alleviate neuro-inflammation at 72 h after stroke. Whereas, more remarkable reduction of iNOS and MMP9 induced by PARP-1 inhibition were found in male MCAO mice, and the improvement of behavioral outcomes was more prominent in male MCAO mice. In addition, we further identified that PARP-1 inhibitor might equivalently suppress microglial activation in males and females in vivo and in vitro. With proteomic analysis and western blotting assay, it was found that stroke-induced peroxiredoxin-1 (Prx1) expression was significantly affected by PARP-1 inhibition. Interestingly, injection of recombinant Prx1 into the ischemic core could block the anti-inflammatory effects of PARP-1 inhibitor in the experimental stroke. These findings suggest that PARP-1 inhibitor has effects on regulating microglial activation and post-stroke inflammation in males and females, and holds promise as a novel therapeutic agent for stroke with extended therapeutic time window. Efforts need to be made to delineate the actions of PARP-1 inhibition in stroke, and here we propose that Prx1 might be a critical mediator.

Exosomes of Antler Mesenchymal Stem Cells Improve Postoperative Cognitive Dysfunction in Cardiopulmonary Bypass Rats through Inhibiting the TLR2/TLR4 Signaling Pathway

Postoperative cognitive dysfunction (POCD) is a severe complication of cardiopulmonary bypass (CPB) and has common characteristics such as acute cognitive dysfunction, impaired memory, and inattention. Mesenchymal stem cells (MSCs) are multipotent cells that have therapeutic potentials mainly through paracrine action via secreting growth factors and cytokines. Exosomes are one of the important paracrine factors and have been reported as potential cell-free therapy for the treatment of autoimmune and central nervous system disorders. In this study, we examined exosomes derived from antler MSCs (AMSCs) of POCD rats after CPB and evaluated their potential regulatory mechanisms. AMSC-derived exosomes reduced neurological damage and brain damage and prevent apoptosis in CPB rats. Furthermore, AMSC-derived exosomes were found to reduce hippocampal neuronal apoptosis and the expression of TLR2, TLR4, MyD88, and NF-κB in CPB rats. However, the above effects of AMSC-derived exosomes on CPB rats were abolished partially by toll-like receptor 2/4 (TLR2/TLR4) agonist (LPS-EB). In conclusion, AMSC-derived exosomes can improve cognitive function in CPB rats through inhibiting the TLR2/TLR4 signaling pathway.

Danhong Injection Protects Hemorrhagic Brain by Increasing Peroxiredoxin 1 in Aged Rats

Intracerebral hemorrhage (ICH) is a severe cerebrovascular disease with a high incidence, mortality and disability rate. Danhong injection (DHI) is beneficial for ischemic stroke, but is prohibited for ICH due to risk of bleeding. The present study aims to explore the potential therapeutic time window and molecular mechanism of DHI in a collagenase-induced ICH model in aged rats. DHI administration after ICH could significantly improve body weight and neurological deficits, and reduce the hematoma volume and brain water content when compared to the vehicle control. Furthermore, the protective effect of DHI administration on days 1–3 after ICH was superior to those on days 3–5 or 7–9 after ICH. DHI remarkably increased the Peroxiredoxin 1 (Prx1) expression in astrocytes and reduced the expression of inflammatory factors tumor necrosis factor-α (TNF-α) and interleukin-β (IL-1β) after ICH. The immediate treatment of Prx1 inhibiter chelerythrine (Che) after ICH abolished the protective effect of DHI. Furthermore, the Che treatment reduced the expression of Prx1 in astrocytes, but increased the expression of TNF-α and IL-1β after ICH. DHI treatment could not reverse these changes. Therefore, the earlier DHI is administered, the better the neuroprotective effect. DHI exerts antioxidative and anti-inflammatory function by increasing Prx1 in astrocytes. These present results may change the established understanding of DHI, and reveal a novel treatment approach for ICH.

Prdx1 Reduces Intracerebral Hemorrhage-Induced Brain Injury via Targeting Inflammation- and Apoptosis-Related mRNA Stability

RNA-binding proteins (RBPs) have been shown to be involved in posttranscriptional regulation, which plays an important role in the pathophysiology of intracerebral hemorrhage (ICH). Peroxiredoxin 1 (Prdx1), an RBP, plays an important role in regulating inflammation and apoptosis. On the basis that inflammation and apoptosis may contribute to ICH-induced brain injury, in this study, we used ICH models coupled with in vitro experiments, to investigate the role and mechanism of Prdx1 in regulating inflammation and apoptosis by acting as an RBP after ICH. We first found that Prdx1 was significantly up-regulated in response to ICH-induced brain injury and was mainly expressed in astrocytes and microglia in ICH rat brains. After overexpressing Prdx1 by injecting adeno-associated virus (AAV) into the striatum of rats at 3 weeks, we constructed ICH models and found that Prdx1 overexpression markedly reduced inflammation and apoptosis after ICH. Furthermore, RNA immunoprecipitation combined with high-throughput sequencing (RIP-seq) in vitro revealed that Prdx1 affects the stability of inflammation- and apoptosis-related mRNA, resulting in the inhibition of inflammation and apoptosis. Finally, overexpression of Prdx1 significantly alleviated the symptoms and mortality of rats subjected to ICH. Our results show that Prdx1 reduces ICH-induced brain injury by targeting inflammation- and apoptosis-related mRNA stability. Prdx1 may be an improved therapeutic target for alleviating the brain injury caused by ICH.

Microglia and macrophage phenotypes in intracerebral haemorrhage injury: therapeutic opportunities

The prognosis of intracerebral haemorrhage continues to be devastating despite much research into this condition. A prominent feature of intracerebral haemorrhage is neuroinflammation, particularly the excessive representation of pro-inflammatory CNS-intrinsic microglia and monocyte-derived macrophages that infiltrate from the circulation. The pro-inflammatory microglia/macrophages produce injury-enhancing factors, including inflammatory cytokines, matrix metalloproteinases and reactive oxygen species. Conversely, the regulatory microglia/macrophages with potential reparative and anti-inflammatory roles are outcompeted in the early stages after intracerebral haemorrhage, and their beneficial roles appear to be overwhelmed by pro-inflammatory microglia/macrophages. In this review, we describe the activation of microglia/macrophages following intracerebral haemorrhage in animal models and clinical subjects, and consider their multiple mechanisms of cellular injury after haemorrhage. We review strategies and medications aimed at suppressing the pro-inflammatory activities of microglia/macrophages, and those directed at elevating the regulatory properties of these myeloid cells after intracerebral haemorrhage. We consider the translational potential of these medications from preclinical models to clinical use after intracerebral haemorrhage injury, and suggest that several approaches still lack the experimental support necessary for use in humans. Nonetheless, the preclinical data support the use of deactivator or inhibitor of pro-inflammatory microglia/macrophages, whilst enhancing the regulatory phenotype, as part of the therapeutic approach to improve the prognosis of intracerebral haemorrhage.

Gabexate mesilate ameliorates the neuropathic pain in a rat model by inhibition of proinflammatory cytokines and nitric oxide pathway via suppression of nuclear factor-κB

Background

This study examined the effects of gabexate mesilate on spinal nerve ligation (SNL)-induced neuropathic pain. To confirm the involvement of gabexate mesilate on neuroinflammation, we focused on the activation of nuclear factor-κB (NF-κB) and consequent the expression of proinflammatory cytokines and inducible nitric oxide synthase (iNOS).

Methods

Male Sprague-Dawley rats were used for the study. After randomization into three groups: the sham-operation group, vehicle-treated group (administered normal saline as a control), and the gabexate group (administered gabexate mesilate 20 mg/kg), SNL was performed. At the 3rd day, mechanical allodynia was confirmed using von Frey filaments, and drugs were administered intraperitoneally daily according to the group. The paw withdrawal threshold (PWT) was examined on the 3rd, 7th, and 14th day. The expressions of p65 subunit of NF-κB, interleukin (IL)-1, IL-6, tumor necrosis factor-α, and iNOS were evaluated on the 7th and 14th day following SNL.

Results

The PWT was significantly higher in the gabexate group compared with the vehicle-treated group (P < 0.05). The expressions of p65, proinflammatory cytokines, and iNOS significantly decreased in the gabexate group compared with the vehicle-treated group (P < 0.05) on the 7th day. On the 14th day, the expressions of p65 and iNOS showed lower levels, but those of the proinflammatory cytokines showed no significant differences.

Conclusions

Gabexate mesilate increased PWT after SNL and attenuate the progress of mechanical allodynia. These results seem to be involved with the anti-inflammatory effect of gabexate mesilate via inhibition of NF-κB, proinflammatory cytokines, and nitric oxide.

The role of Toll-like receptor 4 in apoptosis of brain tissue after induction of intracerebral hemorrhage

Background

Inflammation and apoptosis caused by intracerebral hemorrhage (ICH) are two important factors that affect patient prognosis and survival. Toll-like receptor 4 (TLR4) triggers activation of the inflammatory pathway, causing synthesis and release of inflammatory factors. The inflammatory environment also causes neuronal apoptosis. However, no studies have reported the role of TLR4 in inflammation and apoptosis.

Methods

We performed survival curve analysis and behavioral scores on TLR4 knockout mice and wild-type mice after inducing ICH. We used TLR4 knockout mice and wild-type mice to make ICH models with type VII collagenase and explored the link between TLR4 in inflammation and apoptosis. We used Western blot to detect the expression of apoptosis-related proteins, inflammatory factors, and their receptors at different time points after ICH induction. The effects of TLR4 on apoptosis were observed by TUNEL, Hoechst, and HE staining techniques. The association with TLR4 in inflammation and apoptosis was explored using IL-1β and TNF-α antagonists. Data conforming to a normal distribution are expressed as mean ± standard deviation. Grade and quantitative data were compared with rank sum test and t test between two groups. P < 0.05 was considered statistically significant.

Results

TLR4 knockout significantly increased the survival rate of ICH mice. The scores of TLR4 knockout mice were significantly lower than those of wild-type mice. We found that TLR4 knockout mice significantly inhibited apoptosis and the expression of inflammatory factors after the induction of ICH. The apoptosis of ICH-induced mice was significantly improved after injecting IL-1β and TNF-α antagonists. Moreover, the anti-apoptotic effect of the antagonist in wild-type mice is more pronounced. A single injection of the antagonist failed to improve apoptosis in TLR4 knockout mice.

Conclusions

We conclude that TLR4-induced inflammation after ICH promotes neuronal apoptosis. IL-1β and TNF-α antagonists attenuate this apoptotic effect. Therefore, targeting TLR4 in patients with clinical ICH may attenuate inflammatory response, thereby attenuating apoptosis and improving prognosis.

Parthenolide ameliorates intracerebral hemorrhage-induced brain injury in rats

Neuroinflammation and oxidative stress are key contributors to intracranial hemorrhage (ICH)-induced brain injury. Parthenolide (PN) is a sesquiterpene lactone that has been observed to have antioxidative, anti-inflammatory, and neuroprotective potentials. However, the role of PN in ICH remains unclear. Therefore, we investigated the neuroprotective effects and underlying mechanisms of PN on an experimental model of ICH in rats. Our results showed that PN treatment improved neurological deficit and brain edema in ICH rats. The ipsilateral hemispheres of the brain were separated and homogenized. The concentrations of TNF-α, interleukin (IL)-6, and IL-17 in the homogenates were detected by enzyme-linked immunosorbent assay. We found that PN inhibited the production of proinflammatory cytokines in an ICH rat model. The ROS and glutathione (GSH) levels, as well as the activity of superoxide dismutase (SOD) in the homogenates were measured. ICH caused an increase in ROS level, and the decreases in GSH level and SOD activity were mitigated by PN treatment. Furthermore, PN significantly suppressed the expressions of active caspase-3 and Bax in ipsilateral hemispheres of the brain at Day 3 after ICH, as well as increased the surviving neurons. Finally, the ICH-induced activation of TLR4/NF-κB pathway was suppressed by PN treatment. These findings suggested that PN could be beneficial in the therapeutic strategy for ICH treatment.

AAV/BBB-Mediated Gene Transfer of CHIP Attenuates Brain Injury Following Experimental Intracerebral Hemorrhage

Cell death is a hallmark of secondary brain injury following intracerebral hemorrhage (ICH). The E3 ligase CHIP has been reported to play a key role in mediating necroptosis-an important mechanism of cell death after ICH. However, there is currently no evidence supporting a function of CHIP in ICH. In the present study, we aimed to determine whether CHIP plays an essential role in brain injury after ICH. Our findings indicated that CHIP expression was increased in the peri-hematomal area in rat models of ICH. The AAV/BBB viral platform enables non-invasive, widespread, and long-lasting global neural expression of target genes. Treatment with AAV/BBB-CHIP ameliorated brain injury and inhibited neuronal necroptosis and inflammation in wild type (WT) rats following ICH. Furthermore, rats with CHIP deficiency experienced severe brain injury and increased levels of neuronal necroptosis and inflammation relative to their WT counterparts. However, treatment with AAV/BBB-CHIP attenuated the effects of CHIP deficiency after ICH. Collectively, our results demonstrate that CHIP inhibits necroptosis and pathological inflammation following ICH, and that overexpression of CHIP may represent a therapeutic intervention for ICH. Moreover, the AAV/BBB viral platform may provide a novel avenue for the treatment of brain injury.

Intracerebral hemorrhage induces monocyte-related gene expression within six hours: Global transcriptional profiling in swine ICH

Intracerebral hemorrhage (ICH) is a severe neurological disorder with no proven treatment. Our prior research identified a significant association with monocyte level and ICH mortality. To advance our understanding, we sought to identify gene expression after ICH using a swine model to test the hypothesis that ICH would induce peripheral blood mononuclear cell (PBMC) gene expression. In 10 pigs with ICH, two PBMC samples were drawn from each with the first immediately prior to ICH induction and the second six hours later. RNA-seq was performed with subsequent bioinformatics analysis using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Ingenuity® Pathway Analysis (IPA). There were 182 significantly upregulated and 153 significantly down-regulated differentially expressed genes (DEGs) after ICH. Consistent with findings in humans, significant GO and KEGG pathways were primarily related to inflammation and the immune response. Five genes, all upregulated post-ICH and known to be associated with monocyte activation, were repeatedly DEGs in the significant KEGG pathways: CD14, TLR4, CXCL8, IL-18, and CXCL2. In IPA, the majority of upregulated disease/function categories were related to inflammation and immune cell activation. TNF and LPS were the most significantly activated upstream regulators, and ERK was the most highly connected node in the top network. ICH induced changes in PBMC gene expression within 6 h of onset related to inflammation, the immune response, and, more specifically, monocyte activation. Further research is needed to determine if these changes affect outcomes and may represent new therapeutic targets.

β-elemene inhibits radiation and hypoxia-induced macrophages infiltration via Prx-1/NF-κB/HIF-1α signaling pathway

Background: In cancers, tumor-associated macrophages (TAMs) play an important role in the progression, evasion of immunity and sensitivity to therapy. Unfortunately, radiation and hypoxia could induce the M2 macrophages infiltration and polarization. Materials and methods: In this study, we investigated the relevance of macrophage recruitment with radiation and hypoxia by transwell. We also evaluated the effect of β-elemene on the infiltration of M2 macrophages and explored its underlying molecular mechanism by a series of in vitro and in vivo experiments. Results: Irradiated or hypoxia lung cancer cells recruit macrophages, and the recruitment is MCP-1 dependent. We also found that radiation and hypoxia-induced MCP-1 secretion follows upregulation of Prx-1, which leads to nuclear accumulation of NF-κB and HIF-1α expression. In addition, β-elemene could effectively suppress this recruitment phenomenon through Prx-1/NF-κB/HIF-1α signaling. Conclusion: Our study showed that radiation and hypoxia significantly promoted the macrophages recruitment. β-elemene could effectively suppress this recruitment phenomenon and MCP-1 expression via inhibiting Prx-1/NF-κB/HIF-1α pathways.

Effect of Inflammation on the Process of Stroke Rehabilitation and Poststroke Depression

A considerable body of evidence has shown that inflammation plays an important role in the process of stroke rehabilitation and development of poststroke depression (PSD). However, the specific molecular and cellular mechanisms involved remain unclear. In this review, we summarize how neuroinflammation affects stroke rehabilitation and PSD. We mainly focus on the immune/inflammatory response, involving astrocytes, microglia, monocyte-derived macrophages, cytokines (tumor necrosis factor alpha, interleukin 1), and microRNAs (microRNA-124, microRNA 133b). This review provides new insights into the effect of inflammation on the process of stroke rehabilitation and PSD and potentially offer new therapeutic targets of stroke and PSD.

Gelatin-Coated Polycaprolactone Nanoparticle-Mediated Naringenin Delivery Rescue Human Mesenchymal Stem Cells from Oxygen Glucose Deprivation-Induced Inflammatory Stress

Ischemic stroke involves pro-inflammatory species, which implicates inflammation in the disease mechanism. Recent studies indicate that the prevalence of therapeutic choice such as stem cell transplantation has seen an upsurge in ischemic stroke. However, after transplantation the fate of transplanted cells is largely unknown. Human mesenchymal stem cells (MSCs), due to their robust survival rate upon transplantation in brain tissue, are being widely employed to treat ischemic stroke. In the present study, we have evaluated naringenin-loaded gelatin-coated polycaprolactone nanoparticles (nar-gel-c-PCL NPs) to rescue MSCs against oxygen glucose deprived insult. Naringenin, due to its strong anti-inflammatory effects, remains a therapeutic choice in neurological disorders. Though, the low solubility and inefficient delivery remain challenges in using naringenin as a therapeutic drug. The present study showed that inflammation occurred in MSCs during their treatment with oxygen glucose deprivation (OGD) and was well overturned by treatment with nar-gel-c-PCL NPs. In brief, the results indicated that nar-gel-c-PCL NPs were able to protect the loss of cell membrane integrity and restored neuronal morphology. Then nar-gel-c-PCL NPs successfully protected the human MSCs against OGD-induced inflammation as evident by reduced level of pro-inflammatory cytokine (TNF-α, IFN-γ, and IL-1β) and other inflammatory biomarkers (COX2, iNOS, and MPO activity). Therefore, the modulation of inflammation by treatment with nar-gel-c-PCL NPs in MSCs could provide a novel strategy to improve MSC-based therapy, and thus, our nanoformulation may find a wide therapeutic application in ischemic stroke and other neuro-inflammatory diseases.

Assessing the Pharmacological and Therapeutic Efficacy of Traditional Chinese Medicine Liangxue Tongyu Prescription for Intracerebral Hemorrhagic Stroke in Neurological Disease Models

Intracerebral hemorrhage is a fatal subtype of stroke, with crucial impact on public health. Surgical removal of the hematoma as an early-stage treatment for ICH can't improve long-term prognosis remarkably. Liangxue tongyu prescription (LP), a Traditional Chinese Medicine (TCM) formula, includes eight ingredients and has been used to treat ICH in the clinical. In the study, we elucidated the pharmacological efficacy and therapeutic efficacy of LP to dissect the mechanism of LP against ICH via network analysis and experimental validation. First, we discovered 34 potential compounds and 146 corresponding targets in LP based on network prediction. 24 signal pathway were obtained by the Clue Go assay based on potential compounds in LP against ICH. Second, we found that LP can not only decreased the level of high sensitive C reactive protein (HS-CRP), tumor necrosis factor-α (TNF-α), NF-kβ, D-dimmer (D2D), estradiol (E2), S-100B, neuron specific enolase (NSE), and interleukin 1 (IL-1) in plasma on spontaneously hypertensive rats (SHRs), but also promoted cell proliferation and inhibited cell apoptosis on the glutamate-induced PC12 cell. The compounds including Taurine, Paeonol, and Ginsenoside Rb1 in LP can activate PI3K/AKT pathway. Third, from the three-factor two-level factorial design, compound combinations in LP, such as Taurine and Paeonol, Taurine and Geniposide, Ginsenoside Rg1, and Ginsenoside Rb1, had first-level interactions on cell proliferation. Compound combinations including Taurine and Paeonol, Ginsenoside Rg1 and Ginsenoside Rb1 had as significant increase in efficiency on inhibiting the apoptosis of PC12 cells at the low concentration and up-regulating of PI3K and AKT. Overall, our results suggested that LP had integrated therapeutic effect on ICH due to activities of anti-inflammatory, anti-coagulation, blood vessel protection, and protection neuron from excitotoxicity based on the way of "multi-component, multi-target, multi-pathway," and compound combination in LP can offer protection neuron from excitotoxicity at the low concentration by activation of the PI3K/Akt signal pathway.

Peroxiredoxin 1/2 protects brain against H2O2-induced apoptosis after subarachnoid hemorrhage

Recent studies suggest that peroxiredoxin1/2 (Prx1/2) may be involved in the pathophysiology of postischemic inflammatory responses in the brain. In this study, we assessed the distribution and function of Prx1/2 in mice after experimental subarachnoid hemorrhage (SAH). We investigated the distribution of Prx1/2 in the brains of mice both in vivo and in vitro using immunofluorescence staining. The expression of Prx1/2 after SAH was determined by Western blot. Adenanthin was used to inhibit Prx1/2 function, and Prx1/2 overexpression was achieved by injecting adeno-associated virus. Oxidative stress and neuronal apoptosis were assessed both in vivo and in vitro. The neurologic function, inflammatory response, and related cellular signals were analyzed. The results showed that Prx1 was mainly expressed in astrocytes, and Prx2 was abundant in neurons. The expression of Prx1/2 was elevated after SAH, and their expression levels peaked before proinflammatory cytokines. Inhibiting Prx1/2 promoted neuronal apoptosis by increasing the hydrogen peroxide (H₂O₂) levels via the apoptosis signal-regulating kinase 1/p38 pathway. By contrast, overexpression of Prx1/2 attenuated oxidative stress and neuronal apoptosis after SAH. Thus, early expression of Prx1/2 may protect the brain from oxidative damage after SAH and may provide a novel target for treating SAH.-Lu, Y., Zhang, X.-S., Zhou, X.-M., Gao, Y.-Y., Chen, C.-L., Liu, J.-P., Ye, Z.-N., Zhang, Z.-H., Wu, L.-Y., Li, W., Hang, C.-H. Peroxiredoxin 1/2 protects brain against H₂O₂-induced apoptosis after subarachnoid hemorrhage.