Role of transcription factors in mediating post-ischemic cerebral inflammation and brain damage

Oroxyloside protects against dextran sulfate sodium-induced colitis by inhibiting ER stress via PPARγ activation

Ulcerative colitis (UC), a prevalent form of inflammatory bowel disease (IBD), may result from immune system dysfunction, leading to the sustained overproduction of reactive oxygen species (ROS) and subsequent cellular oxidative stress damage. Recent studies have identified both peroxisome proliferator-activated receptor-γ (PPARγ) and endoplasmic reticulum (ER) stress as critical targets for the treatment of IBD. Oroxyloside (C22H20O11), derived from the root of Scutellariabaicalensis Georgi, has traditionally been used in treating inflammatory diseases. In this study, we investigated the molecular mechanisms by which oroxyloside mitigates dextran sulfate sodium (DSS)-induced colitis. We examined the effects of oroxyloside on ROS-mediated ER stress in colitis, including the protein expressions of GRP78, p-PERK, p-eIF2α, ATF4, and CHOP, which are associated with ER stress. The beneficial impact of oroxyloside was reversed by the PPARγ antagonist GW9662 (1 mg·kg-1, i.v.) in vivo. Furthermore, oroxyloside decreased pro-inflammatory cytokines and ROS production in both bone marrow-derived macrophages (BMDM) and the mouse macrophage cell line RAW 264.7. However, PPARγ siRNA transfection blocked the anti-inflammatory effect of oroxyloside and even abolished ROS generation and ER stress activation inhibited by oroxyloside in vitro. In conclusion, our study demonstrates that oroxyloside ameliorates DSS-induced colitis by inhibiting ER stress via PPARγ activation, suggesting that oroxyloside might be a promising effective agent for IBD.

Progressive microvascular failure in acute ischemic stroke: A systematic review, meta-analysis, and time-course analysis

This systematic review, meta-analysis, and novel time course analysis examines microvascular failure in the treatment of acute ischemic stroke (AIS) patients undergoing endovascular therapy (EVT) and/or thrombolytic administration for stroke management. A systematic review and meta-analysis following PRIMSA-2020 guidelines was conducted along with a novel curve-of-best fit analysis to elucidate the time-course of microvascular failure. Scopus and PubMed were searched using relevant keywords to identify studies that examine recanalization and reperfusion assessment of AIS patients following large vessel occlusion. Meta-analysis was conducted using a random-effects model. Curve-of-best-fit analysis of microvascular failure rate was performed with a negative exponential model. Twenty-seven studies with 1151 patients were included. Fourteen studies evaluated patients within a standard stroke onset-to-treatment time window (≤6 hours after last known normal) and thirteen studies had an extended time window (>6 hours). Our analysis yields a 22% event rate of microvascular failure following successful recanalization (95% CI: 16-30%). A negative exponential curve modeled a microvascular failure rate asymptote of 28.5% for standard time window studies, with no convergence of the model for extended time window studies. Progressive microvascular failure is a phenomenon that is increasingly identified in clinical studies of AIS patients undergoing revascularization treatment.

Role of transcription factors, noncoding RNAs, epitranscriptomics, and epigenetics in post-ischemic neuroinflammation

Post-stroke neuroinflammation is pivotal in brain repair, yet persistent inflammation can aggravate ischemic brain damage and hamper recovery. Following stroke, specific molecules released from brain cells attract and activate central and peripheral immune cells. These immune cells subsequently release diverse inflammatory molecules within the ischemic brain, initiating a sequence of events, including activation of transcription factors in different brain cell types that modulate gene expression and influence outcomes; the interactive action of various noncoding RNAs (ncRNAs) to regulate multiple biological processes including inflammation, epitranscriptomic RNA modification that controls RNA processing, stability, and translation; and epigenetic changes including DNA methylation, hydroxymethylation, and histone modifications crucial in managing the genic response to stroke. Interactions among these events further affect post-stroke inflammation and shape the depth of ischemic brain damage and functional outcomes. We highlighted these aspects of neuroinflammation in this review and postulate that deciphering these mechanisms is pivotal for identifying therapeutic targets to alleviate post-stroke dysfunction and enhance recovery.

Immune pathway activation in neurons triggers neural damage after stroke

Ischemic brain injury is a severe medical condition with high incidences in elderly people without effective treatment for the resulting neural damages. Using a unilateral mouse stroke model, we analyze single-cell transcriptomes of ipsilateral and contralateral cortical penumbra regions to objectively reveal molecular events with single-cell resolution at 4 h and 1, 3, and 7 days post-injury. Here, we report that neurons are among the first cells that sense the lack of blood supplies by elevated expression of CCAAT/enhancer-binding protein β (C/EBPβ). To our surprise, the canonical inflammatory cytokine gene targets for C/EBPβ, including interleukin-1β (IL-1β) and tumor necrosis factor α (TNF-α), are subsequently induced also in neuronal cells. Neuronal-specific silencing of C/EBPβ or IL-1β and TNF-α substantially alleviates downstream inflammatory injury responses and is profoundly neural protective. Taken together, our findings reveal a neuronal inflammatory mechanism underlying early pathological triggers of ischemic brain injury.

Phytocompounds of Nigella sativa seeds extract and their neuroprotective potential via EGR1 receptor inhibition: A molecular docking study

Bioactivity of Nigella sativa seed extract has the potential as a neuro-protector, offering its promising utility in the clinical setting for brain injury management. This study aimed to identify the phytocompounds contained in the extract of N. sativa seeds and further screen their respective neuronal anti-inflammatory activities in silico. The extract of N. sativa seeds was prepared through successive maceration using non-polar to polar solvents (n-hexane and ethanol, respectively). The phytocompounds in the ethanolic extract were initially identified through qualitative analysis and further analyzed with gas chromatography-mass spectrometry (GC-MS). The spectral data were compared with the compound library for identification. The identified phytocompounds were then simulated computationally for their binding affinities toward the active pocket of early growth response-1 (EGR1) receptor (PDB: 14r2a). We found that the ethanolic extract of N. sativa seeds were predominantly constituted of hexadecanoic acid, ethyl ester (17.15%); linoleic acid ethyl ester (15.0%); octadecanoic acid (13.26%); and ethyl oleate (10.38%). The binding affinity of the phytocompounds ranged from -7.49 kcal/mol (methyl palmitoleate) to -14.31 kcal/mol (9-hexadecanoic acid, methyl ester), with 12 compounds having binding affinity < -10 kcal/mol. In conclusion, ethanolic extract of N. sativa seeds are rich with fatty acids that have active as anti-inflammatory and may exert neuronal protection by inhibiting EGR1 receptor. Studies using animal models to confirm the activity are warranted.

Evaluation of syringin's neuroprotective effect in a model of neonatal hypoxic-ischemic brain injury

Background/aim

A significant cause of mortality and morbidity in the neonatal era is hypoxic-ischemic encephalopathy (HIE). This study examined the histopathological analysis and neuroprotective impact of syringin (SYR) in an experimental HIE rat model.

Material and methods

On the 7th postnatal day, 24 Wistar albino rats were evaluated in 3 groups using the HIE model under gas anesthesia. In the experiment, Group A received 10 mg/kg SYR plus dimethyl sulfoxide (DMSO), Group B received DMSO only, and Group C served as a sham group. Immunohistochemical techniques were used to assess apoptotic cell measurement and proinflammatory cytokines (TNF-α and IL-1β primary antibodies).

Results

Rats suffering from hypoxic-ischemic brain damage had their apoptosis assessed. The SYR and sham groups had statistically fewer cells undergoing apoptosis (p < 0.001). There was no difference between the groups in terms of IL-1β and TNF-α during immunohistochemical staining. Neuronal degeneration was significantly lower in the histological evaluation of the hippocampus in the SYR group (p = 0.01). A statistically significant difference (p = 0.01) was observed between the SYR and the control groups regarding pericellular and perivascular edema.

Conclusion

SYR reduced apoptosis, perivascular and pericellular edema, and neuronal degeneration in rat cerebral tissue. These results raise the possibility that SYR may have a neuroprotective effect on the harm brought on by HIE. This is the first investigation of SYR's function within the HIE paradigm.

Bioinformatics and experimental analyses of glutamate receptor and its targets genes in myocardial and cerebral ischemia

BACKGROUND

There is a mutual hemodynamic and pathophysiological basis between the heart and brain. Glutamate (GLU) signaling plays an important role in the process of myocardial ischemia (MI) and ischemic stroke (IS). To further explore the common protective mechanism after cardiac and cerebral ischemic injuries, the relationship between GLU receptor-related genes and MI and IS were analyzed.

RESULTS

A total of 25 crosstalk genes were identified, which were mainly enriched in the Toll-like receptor signaling pathway, Th17 cell differentiation, and other signaling pathways. Protein-protein interaction analysis suggested that the top six genes with the most interactions with shared genes were IL6, TLR4, IL1B, SRC, TLR2, and CCL2. Immune infiltration analysis suggested that immune cells such as myeloid-derived suppressor cells and monocytes were highly expressed in the MI and IS data. Memory B cells and Th17 cells were expressed at low levels in the MI and IS data; molecular interaction network construction suggested that genes such as JUN, FOS, and PPARA were shared genes and transcription factors; FCGR2A was a shared gene of MI and IS as well as an immune gene. Least absolute shrinkage and selection operator logistic regression analysis identified nine hub genes: IL1B, FOS, JUN, FCGR2A, IL6, AKT1, DRD4, GLUD2, and SRC. Receiver operating characteristic analysis revealed that the area under the curve of these hub genes was > 65% in MI and IS for all seven genes except IL6 and DRD4. Furthermore, clinical blood samples and cellular models showed that the expression of relevant hub genes was consistent with the bioinformatics analysis.

CONCLUSIONS

In this study, we found that the GLU receptor-related genes IL1B, FOS, JUN, FCGR2A, and SRC were expressed in MI and IS with the same trend, which can be used to predict the occurrence of cardiac and cerebral ischemic diseases and provide reliable biomarkers to further explore the co-protective mechanism after cardiac and cerebral ischemic injury.

Fecal microbiota transplantation and short-chain fatty acids protected against cognitive dysfunction in a rat model of chronic cerebral hypoperfusion

AIMS

Clear roles and mechanisms in explaining gut microbial dysbiosis and microbial metabolites short-chain fatty acids (SCFAs) alterations in chronic cerebral ischemic pathogenesis have yet to be explored. In this study, we investigated chronic cerebral hypoperfusion (CCH)-induced gut microbiota and metabolic profiles of SCFAs as well as the effects and mechanisms of fecal microbiota transplantation (FMT) and SCFAs treatment on CCH-induced hippocampal neuronal injury.

METHODS

Bilateral common carotid artery occlusion (BCCAo) was used to establish the CCH model. Gut microbiota and SCFAs profiles in feces and hippocampus were evaluated by 16S ribosomal RNA sequencing and gas chromatography-mass spectrometry. RNA sequencing analysis was performed in hippocampal tissues. The potential molecular pathways and differential genes were verified through western blot, immunoprecipitation, immunofluorescence, and ELISA. Cognitive function was assessed via the Morris water maze test. Ultrastructures of mitochondria and synapses were tested through a transmission electron microscope.

RESULTS

Chronic cerebral hypoperfusion induced decreased fecal acetic and propionic acid and reduced hippocampal acetic acid, which were reversed after FMT and SCFAs administration by changing fecal microbial community structure and compositions. Furthermore, in the hippocampus, FMT and SCFAs replenishment exerted anti-neuroinflammatory effects through inhibiting microglial and astrocytic activation as well as switching microglial phenotype from M1 toward M2. Moreover, FMT and SCFAs treatment alleviated neuronal loss and microglia-mediated synaptic loss and maintained the normal process of synaptic vesicle fusion and release, resulting in the improvement of synaptic plasticity. In addition, FMT and SCFAs supplement prevented oxidative phosphorylation dysfunction via mitochondrial metabolic reprogramming. The above effects of FMT and SCFAs treatment led to the inhibition of CCH-induced cognitive impairment.

CONCLUSION

Our findings highlight FMT and SCFAs replenishment would be the feasible gut microbiota-based strategy to mitigate chronic cerebral ischemia-induced neuronal injury.

In silico identification of molecular mechanisms for stroke risk caused by heavy metals and their mixtures: sponges and drugs involved

This study used various approaches and databases to evaluate the molecular processes and identify miRNA sponges and drugs associated with the development of stroke caused by heavy metals and their combinations. We found that the genes ALB (albumin), IL1B (Interleukin-1β), F2 (coagulation factor II), APOA1 (apolipoprotein A1), IL6 (Interleukin 6), and NOS2 (nitric oxide synthase 2) were linked to the development of strokes by 18 chemicals and a combination of cadmium, copper, and lead. These results may point to the significance of detoxification and neuroinflammation in stroke as well as the potential for targeting these genes in future stroke therapies. ALB and IL1B were the most common and significant genes. The "selenium micronutrient network," "vitamin B12 metabolism," and "folate metabolism" were shown to be the most significant pathways connected to the risk of stroke brought on by combined heavy metals. The two main cellular elements that may increase the risk of stroke caused by heavy metals were discovered to be "blood microparticle" and "endoplasmic reticulum lumen." We also observed an important chromosome (chr7p15.3), two transcription factors (NFKB2 [nuclear factor kappa B subunit 2] and NR1I2 [nuclear receptor subfamily 1 group, member 2]), and four microRNAs (hsa-miR-26a-5p, hsa-miR-9-5p, hsa-miR-124-3p, and hsa-miR-155-5p) associated with stroke caused by combined heavy metals. Additionally, for these miRNAs, we created and examined in silico microRNA sponge sequences. Triflusal and andrographolide have been identified as potential treatments for heavy metal-induced stroke. Taken together, heavy metals may be a significant contributor to the pathophysiology of stroke, but further investigation into the precise molecular pathways implicated in stroke pathophysiology is required to corroborate these findings.

Insight into the transcription factors regulating Ischemic Stroke and Glioma in Response to Shared Stimuli

Cerebral ischemic stroke and glioma are the two leading causes of patient mortality globally. Despite physiological variations, 1 in 10 people who have an ischemic stroke go on to develop brain cancer, most notably gliomas. In addition, glioma treatments have also been shown to increase the risk of ischemic strokes. Stroke occurs more frequently in cancer patients than in the general population, according to traditional literature. Unbelievably, these events share multiple pathways, but the precise mechanism underlying their co-occurrence remains unknown. Transcription factors (TFs), the main components of gene expression programmes, finally determine the fate of cells and homeostasis. Both ischemic stroke and glioma exhibit aberrant expression of a large number of TFs, which are strongly linked to the pathophysiology and progression of both diseases. The precise genomic binding locations of TFs and how TF binding ultimately relates to transcriptional regulation remain elusive despite a strong interest in understanding how TFs regulate gene expression in both stroke and glioma. As a result, the importance of continuing efforts to understand TF-mediated gene regulation is highlighted in this review, along with some of the primary shared events in stroke and glioma.

Therapeutic modulation of JAK-STAT, mTOR, and PPAR-γ signaling in neurological dysfunctions

The cytokine-activated Janus kinase (JAK)-signal transducer and activator of transcription (STAT) cascade is a pleiotropic pathway that involves receptor subunit multimerization. The mammalian target of rapamycin (mTOR) is a ubiquitously expressed serine-threonine kinase that perceives and integrates a variety of intracellular and environmental stimuli to regulate essential activities such as cell development and metabolism. Peroxisome proliferator-activated receptor-gamma (PPARγ) is a prototypical metabolic nuclear receptor involved in neural differentiation and axon polarity. The JAK-STAT, mTOR, and PPARγ signaling pathways serve as a highly conserved signaling hub that coordinates neuronal activity and brain development. Additionally, overactivation of JAK/STAT, mTOR, and inhibition of PPARγ signaling have been linked to various neurocomplications, including neuroinflammation, apoptosis, and oxidative stress. Emerging research suggests that even minor disruptions in these cellular and molecular processes can have significant consequences manifested as neurological and neuropsychiatric diseases. Of interest, target modulators have been proven to alleviate neuronal complications associated with acute and chronic neurological deficits. This research-based review explores the therapeutic role of JAK-STAT, mTOR, and PPARγ signaling modulators in preventing neuronal dysfunctions in preclinical and clinical investigations.

Kaempferol Protects Against Retinal Photoreceptor Degeneration in a Mouse Model of Light-Induced Retinal Injury

Purpose: Age-related macular degeneration (AMD) is a leading cause of blindness in developed countries with little in the way of treatment that prevents progression to end-stage disease. Kaempferol (KF) is a plant-derived dietary flavonoid that has demonstrated as a strong antioxidant showing neuroprotection in stroke models. We hypothesize that KF has protective effects against retinal degeneration and may serve as a therapeutic agent against AMD. Methods: BALB/c albino mice were assigned to 1 of 2 groups: control-treated or KF-treated retinal light injury mice. Mice were exposed to 8,000 lux cool white fluorescent light for 2 h to induce light injury. Control or KF was injected intraperitoneally after light injury for 5 days. Scotopic electroretinography (ERG) was recorded before light injury and 7 days after light injury. The retinal morphology and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays were performed after light injury. Results: ERG a- and b-wave amplitudes were significantly reduced in the retinal light injury group compared with the nonretinal light injury group. Retinal light injury produced markedly thinning of the outer nuclear layer along with significant TUNEL-positive signals. In contrast KF treatments significantly attenuated reduction of ERG a- and b- wave amplitudes and the loss of the outer nuclear layer. Conclusions: KF protects retinal photoreceptors and preserves retinal function against retinal degeneration caused by light injury. These initial findings suggest that KF may represent a novel therapy for retinal degenerative conditions such as AMD.

Insight into Glyproline Peptides' Activity through the Modulation of the Inflammatory and Neurosignaling Genetic Response Following Cerebral Ischemia-Reperfusion

Glyprolines are Gly-Pro (GP)- or Pro-Gly (PG)-containing biogenic peptides. These peptides can act as neutrophil chemoattractants, or atheroprotective, anticoagulant, and neuroprotective agents. The Pro-Gly-Pro (PGP) tripeptide is an active factor of resistance to the biodegradation of peptide drugs. The synthetic Semax peptide, which includes Met-Glu-His-Phe (MEHF) fragments of adrenocorticotropic hormone and the C-terminal tripeptide PGP, serves as a neuroprotective drug for the treatment of ischemic stroke. Previously, we revealed that Semax mostly prevented the disruption of the gene expression pattern 24 h after a transient middle cerebral artery occlusion (tMCAO) in a rat brain model. The genes of this pattern were grouped into an inflammatory cluster (IC) and a neurotransmitter cluster (NC). Here, using real-time RT-PCR, the effect of other PGP-containing peptides, PGP and Pro-Gly-Pro-Leu (PGPL), on the expression of a number of genes in the IC and NC was studied 24 h after tMCAO. Both the PGP and PGPL peptides showed Semax-unlike effects, predominantly without changing gene expression 24 h after tMCAO. Moreover, there were IC genes (iL1b, iL6, and Socs3) for PGP, as well as IC (iL6, Ccl3, Socs3, and Fos) and NC genes (Cplx2, Neurod6, and Ptk2b) for PGPL, that significantly changed in expression levels after peptide administration compared to Semax treatment under tMCAO conditions. Furthermore, gene enrichment analysis was carried out, and a regulatory gene network was constructed. Thus, the spectra of the common and unique effects of the PGP, PGPL, and Semax peptides under ischemia-reperfusion were distinguished.

LncRNA nuclear-enriched abundant transcript 1 aggravates cerebral ischemia/reperfusion injury through activating early growth response-1/RNA binding motif protein 25 axis

Ischemic stroke is a major global health issue. Ischemia and subsequent reperfusion results in stroke-related brain injury. Previous studies have demonstrated that nuclear-enriched abundant transcript 1 (NEATa and early growth response 1 (EGR1) are involved in ischemia reperfusion (IR) injury). In this study, we aimed to explore the roles of NEAT1/EGR1 axis as well as its downstream effector RNA binding motif protein 25 (RBM25) in cerebral IR injury. Oxygen-glucose deprivation/reperfusion (OGD/R) and middle cerebral artery occlusion (MCAO) were used to establish in vitro and in vivo models of cerebral IR injury, respectively. According to our data, NEAT1, EGR1, and RBM25 levels were elevated in OGD/R-exposed SK-N-SH and SH-SY5Y cells and cerebral cortex of MCAO mice. NEAT1, EGR1, or RBM25 knockdown effectively reduced infarct volumes and apoptosis, and improved neurological function. Mechanistically, NEAT1 directly interacted with EGR1, which restrained WW domain containing E3 ubiquitin protein ligase 1 (WWP1)-mediated ubiquitination of EGR1 and subsequently caused EGR1 accumulation. EGR1 bound to RBM25 promoter and transcriptionally activated RBM25. Rescue experiments indicated that RBM25 overexpression abolished the therapeutic effects of NEAT1 knockdown. In conclusion, this work identified a novel NEAT1/EGR1/RBM25 axis in potentiating brain injury after IR insults, suggesting a potential therapeutic target for ischemic stroke.

Motor Cortex Plasticity During Functional Recovery Following Brain Damage

Although brain damage causes functional impairment, it is often followed by partial or total recovery of function. Recovery is believed to occur primarily because of brain plasticity. Both human and animal studies have significantly contributed to uncovering the neuronal basis of plasticity. Recent advances in brain imaging technology have enabled the investigation of plastic changes in living human brains. In addition, animal experiments have revealed detailed changes at the neural and genetic levels. In this review, plasticity in motor-related areas of the cerebral cortex, which is one of the most well-studied areas of the neocortex in terms of plasticity, is reviewed. In addition, the potential of technological interventions to enhance plasticity and promote functional recovery following brain damage is discussed. Novel neurorehabilitation technologies are expected to be established based on the emerging research on plasticity from the last several decades.

Identification of hub Genes in the Pathogenesis of Ischemic Stroke Based on Bioinformatics Analysis

Objective

The present study aimed to identify the function of ischemic stroke (IS) patients’ peripheral blood and its role in IS, explore the pathogenesis, and provide direction for clinical research progress by comprehensive bioinformatics analysis.

Methods

Two datasets, including GSE58294 and GSE22255, were downloaded from Gene Expression Omnibus database. GEO2R was utilized to obtain differentially expressed genes (DEGs). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of DEGs were performed using the database annotation, visualization and integrated discovery database. The protein-protein interaction (PPI) network of DEGs was constructed by search tool of searching interactive gene and visualized by Cytoscape software, and then the Hub gene was identified by degree analysis. The microRNA (miRNA) and miRNA target genes closely related to the onset of stroke were obtained through the miRNA gene regulatory network.

Results

In total, 36 DEGs, containing 27 up-regulated and nine down-regulated DEGs, were identified. GO functional analysis showed that these DEGs were involved in regulation of apoptotic process, cytoplasm, protein binding and other biological processes. KEGG enrichment analysis showed that these DEGs mediated signaling pathways, including HTLV-I infection and microRNAs in cancer. The results of PPI network and cytohubba showed that there was a relationship between DEGs, and five hub genes related to stroke were obtained : SOCS3, KRAS, PTGS2, EGR1, and DUSP1. Combined with the visualization of DEG-miRNAs, hsa-mir-16-5p, hsa-mir-181a-5p and hsa-mir-124-3p were predicted to be the key miRNAs in stroke, and three miRNAs were related to hub gene.

Conclusion

Thirty-six DEGs, five Hub genes, and three miRNA were obtained from bioinformatics analysis of IS microarray data, which might provide potential targets for diagnosis and treatment of IS.

The delivery of miR-21a-5p by extracellular vesicles induces microglial polarization via the STAT3 pathway following hypoxia-ischemia in neonatal mice

Extracellular vesicles (EVs) from mesenchymal stromal cells (MSCs) have previously been shown to protect against brain injury caused by hypoxia-ischemia (HI). The neuroprotective effects have been found to relate to the anti-inflammatory effects of EVs. However, the underlying mechanisms have not previously been determined. In this study, we induced oxygen-glucose deprivation in BV-2 cells (a microglia cell line), which mimics HI in vitro, and found that treatment with MSCs-EVs increased the cell viability. The treatment was also found to reduce the expression of pro-inflammatory cytokines, induce the polarization of microglia towards the M2 phenotype, and suppress the phosphorylation of selective signal transducer and activator of transcription 3 (STAT3) in the microglia. These results were also obtained in vivo using neonatal mice with induced HI. We investigated the potential role of miR-21a-5p in mediating these effects, as it is the most highly expressed miRNA in MSCs-EVs and interacts with the STAT3 pathway. We found that treatment with MSCs-EVs increased the levels of miR-21a-5p in BV-2 cells, which had been lowered following oxygen-glucose deprivation. When the level of miR-21a-5p in the MSCs-EVs was reduced, the effects on microglial polarization and STAT3 phosphorylation were reduced, for both the in vitro and in vivo HI models. These results indicate that MSCs-EVs attenuate HI brain injury in neonatal mice by shuttling miR-21a-5p, which induces microglial M2 polarization by targeting STAT3.

RNA-seq analysis reveals potential molecular mechanisms of ZNF580/ZFP580 promoting neuronal survival and inhibiting apoptosis after Hypoxic-ischemic brain damage

Neonatal hypoxic-ischemic brain damage (HIBD) is one of the main causes of neonatal acute death and chronic nervous system impairment, but still lacks effective treatments. ZNF580/ZFP580, reported in our previous studies, may be a newly identified member of the Krüppel-like factor (KLF) family, and has anti-apoptotic effects during ischemic myocardial injury. In the present study, we showed that the expression levels of both ZFP580/ZNF580 mRNA and protein increased significantly in neonatal HIBD rats and oxygen-glucose deprivation (OGD) SH-SY5Y cell models. ZNF580 overexpression promoted neuron survival and suppressed neuron apoptosis after OGD in neuron-like SH-SY5Y cells, while interference with ZNF580 resulted in the opposite results. RNA-seq analysis identified 248 differentially-expressed genes (DEGs) between ZNF580 overexpression SH-SY5Y cells and interference-expressed SH-SY5Y cells. Gene Ontology functional enrichment analysis showed that these DEGs played significant roles in the growth, development, and regeneration of axons, DNA biosynthetic processes, DNA replication, and apoptosis. Kyoto Encyclopedia of Genes and Genomes enrichment analysis indicated that these DEGs were found in some pathways, including ferroptosis, glutamatergic synapses, protein processing in the endoplasmic reticulum, estrogen signaling pathways, the TGF-beta signaling pathway, and the longevity regulating pathway. The qRT-PCR validation results were consistent with RNA-seq results, which showed that HSPA5, IGFBP3, NTN4, and KLF9 increased in ZNF580-overexpressed SH-SY5Y cells and decreased in interference-expressed SH-SY5Y cells, when compared with normal cells. Together, the results suggested that ZNF580 targeted these genes to inhibit neuronal apoptosis.

MicroRNA miR-21 Decreases Post-stroke Brain Damage in Rodents

Due to their role in controlling translation, microRNAs emerged as novel therapeutic targets to modulate post-stroke outcomes. We previously reported that miR-21 is the most abundantly induced microRNA in the brain of rodents subjected to preconditioning-induced cerebral ischemic tolerance. We currently show that intracerebral administration of miR-21 mimic decreased the infarct volume and promoted better motor function recovery in adult male and female C57BL/6 mice subjected to transient middle cerebral artery occlusion. The miR-21 mimic treatment is also efficacious in aged mice of both sexes subjected to focal ischemia. Mechanistically, miR-21 mimic treatment decreased the post-ischemic levels of several pro-apoptotic and pro-inflammatory RNAs, which might be responsible for the observed neuroprotection. We further observed post-ischemic neuroprotection in adult mice administered with miR-21 mimic intravenously. Overall, the results of this study implicate miR-21 as a promising candidate for therapeutic translation after stroke.

Epigenetic Regulations of Microglia/Macrophage Polarization in Ischemic Stroke

Ischemic stroke is one of the leading causes of death and disability worldwide. Microglia/macrophages (MMs)-mediated neuroinflammation contributes significantly to the pathological process of ischemic brain injury. Microglia, serving as resident innate immune cells in the central nervous system, undergo pro-inflammatory phenotype or anti-inflammatory phenotype in response to the microenvironmental changes after cerebral ischemia. Emerging evidence suggests that epigenetics modifications, reversible modifications of the phenotype without changing the DNA sequence, could play a pivotal role in regulation of MM polarization. However, the knowledge of the mechanism of epigenetic regulations of MM polarization after cerebral ischemia is still limited. In this review, we present the recent advances in the mechanisms of epigenetics involved in regulating MM polarization, including histone modification, non-coding RNA, and DNA methylation. In addition, we discuss the potential of epigenetic-mediated MM polarization as diagnostic and therapeutic targets for ischemic stroke. It is valuable to identify the underlying mechanisms between epigenetics and MM polarization, which may provide a promising treatment strategy for neuronal damage after cerebral ischemia.

Cell death inhibitors protect against brain damage caused by cardiac ischemia/reperfusion injury

Cognitive impairment has been reported in patients with myocardial infarction despite a successful reperfusion therapy. Several modes of cell death are involved in brain damage during cardiac ischemia/reperfusion (I/R) injury. Although apoptosis, necroptosis, and ferroptosis inhibitors provided neuroprotection against cerebral I/R injury, the effects of these cell death inhibitors on the brain following cardiac I/R injury have never been investigated. We hypothesized that apoptosis, necroptosis, and ferroptosis inhibitors attenuate brain damage following cardiac I/R injury. One-hundred and twenty-six male rats were used: 6 rats were assigned to sham operation and 120 rats were subjected to 30-min regional cardiac ischemia and 120-min reperfusion. Rats in cardiac I/R group were pretreated with either vehicle (n = 12) or one of cell death inhibitors. Rats treated with apoptosis, necroptosis, or ferroptosis inhibitor were subdivided into three different doses including low (L), medium (M), and high (H) doses (n = 12/group). Z-VAD, necrostatin-1 (Nec-1), and ferrostatin-1 (Fer-1) were used as apoptosis, necroptosis, and ferroptosis inhibitor, respectively. Rats were sacrificed at the end of reperfusion, and the brain was used to analyze dendritic spine density, Alzheimer's disease (AD)-related proteins, blood-brain barrier (BBB) tight junction proteins, mitochondrial function, inflammation, and cell death. Our data showed that cardiac I/R led to brain damage and only apoptosis occurred in the hippocampus after cardiac I/R injury. In the cardiac I/R group, treatment with M-Z-VAD and all doses of Nec-1 decreased hippocampal apoptosis and amyloid beta aggregation, thereby reducing dendritic spine loss. M- and H-Fer-1 also reduced dendritic spine loss by suppressing ACSL4, TNF-α, amyloid beta, and tau hyperphosphorylation. Moreover, Bax/Bcl-2 was decreased in all treatment regimen except L-Z-VAD. Additionally, M-Z-VAD and M-Fer-1 partially attenuated mitochondrial dysfunction. Only L-Nec-1 preserved BBB proteins. In conclusion, cell death inhibitors prevented hippocampal dendritic spine loss caused by cardiac I/R injury through different mechanisms.

Brain Protein Expression Profile Confirms the Protective Effect of the ACTH(4-7)PGP Peptide (Semax) in a Rat Model of Cerebral Ischemia-Reperfusion

The Semax (Met-Glu-His-Phe-Pro-Gly-Pro) peptide is a synthetic melanocortin derivative that is used in the treatment of ischemic stroke. Previously, studies of the molecular mechanisms underlying the actions of Semax using models of cerebral ischemia in rats showed that the peptide enhanced the transcription of neurotrophins and their receptors and modulated the expression of genes involved in the immune response. A genome-wide RNA-Seq analysis revealed that, in the rat transient middle cerebral artery occlusion (tMCAO) model, Semax suppressed the expression of inflammatory genes and activated the expression of neurotransmitter genes. Here, we aimed to evaluate the effect of Semax in this model via the brain expression profiling of key proteins involved in inflammation and cell death processes (MMP-9, c-Fos, and JNK), as well as neuroprotection and recovery (CREB) in stroke. At 24 h after tMCAO, we observed the upregulation of active CREB in subcortical structures, including the focus of the ischemic damage; downregulation of MMP-9 and c-Fos in the adjacent frontoparietal cortex; and downregulation of active JNK in both tissues under the action of Semax. Moreover, a regulatory network was constructed. In conclusion, the suppression of inflammatory and cell death processes and the activation of recovery may contribute to the neuroprotective action of Semax at both the transcriptome and protein levels.

Time-Resolved and Comprehensive Analysis of Surface Glycoproteins Reveals Distinct Responses of Monocytes and Macrophages to Bacterial Infection

Glycoproteins on the surface of immune cells play extremely important roles in response to pathogens. Yet, a systematic and time-resolved investigation of surface glycoproteins during the immune response remains to be explored. Integrating selective enrichment of surface glycoproteins with multiplexed proteomics, we globally and site-specifically quantified the dynamics of surface glycoproteins on THP-1 monocytes and macrophages in response to bacterial infection and during the monocyte-to-macrophage differentiation. The time-resolved analysis reveals transient changes and differential remodeling of surface glycoproteins on both cell types, and potential upstream regulators and downstream effects of the regulated glycoproteins. Besides, we identified novel surface glycoproteins participating in the immune response such as APMAP, and site-specific changes of glycoproteins. This study provides unprecedented information to deepen our understanding of glycoproteins and cellular activities.

Time-Resolved and Comprehensive Analysis of Surface Glycoproteins Reveals Distinct Responses of Monocytes and Macrophages to Bacterial Infection

Glycoproteins on the surface of immune cells play extremely important roles in response to pathogens. Yet, a systematic and time-resolved investigation of surface glycoproteins during the immune response remains to be explored. Integrating selective enrichment of surface glycoproteins with multiplexed proteomics, we globally and site-specifically quantified the dynamics of surface glycoproteins on THP-1 monocytes and macrophages in response to bacterial infection and during the monocyte-to-macrophage differentiation. The time-resolved analysis reveals transient changes and differential remodeling of surface glycoproteins on both cell types, and potential upstream regulators and downstream effects of the regulated glycoproteins. Besides, we identified novel surface glycoproteins participating in the immune response such as APMAP, and site-specific changes of glycoproteins. This study provides unprecedented information to deepen our understanding of glycoproteins and cellular activities.

Neuroprotective Phytochemicals in Experimental Ischemic Stroke: Mechanisms and Potential Clinical Applications

Ischemic stroke is a challenging disease with high mortality and disability rates, causing a great economic and social burden worldwide. During ischemic stroke, ionic imbalance and excitotoxicity, oxidative stress, and inflammation are developed in a relatively certain order, which then activate the cell death pathways directly or indirectly via the promotion of organelle dysfunction. Neuroprotection, a therapy that is aimed at inhibiting this damaging cascade, is therefore an important therapeutic strategy for ischemic stroke. Notably, phytochemicals showed great neuroprotective potential in preclinical research via various strategies including modulation of calcium levels and antiexcitotoxicity, antioxidation, anti-inflammation and BBB protection, mitochondrial protection and antiapoptosis, autophagy/mitophagy regulation, and regulation of neurotrophin release. In this review, we summarize the research works that report the neuroprotective activity of phytochemicals in the past 10 years and discuss the neuroprotective mechanisms and potential clinical applications of 148 phytochemicals that belong to the categories of flavonoids, stilbenoids, other phenols, terpenoids, and alkaloids. Among them, scutellarin, pinocembrin, puerarin, hydroxysafflor yellow A, salvianolic acids, rosmarinic acid, borneol, bilobalide, ginkgolides, ginsenoside Rd, and vinpocetine show great potential in clinical ischemic stroke treatment. This review will serve as a powerful reference for the screening of phytochemicals with potential clinical applications in ischemic stroke or the synthesis of new neuroprotective agents that take phytochemicals as leading compounds.

A delta-secretase-truncated APP fragment activates CEBPB, mediating Alzheimer's disease pathologies

Amyloid-β precursor protein (APP) is sequentially cleaved by secretases and generates amyloid-β, the major components in senile plaques in Alzheimer's disease. APP is upregulated in human Alzheimer's disease brains. However, the molecular mechanism of how APP contributes to Alzheimer's disease pathogenesis remains incompletely understood. Here we show that truncated APP C586-695 fragment generated by δ-secretase directly binds to CCAAT/enhancer-binding protein beta (CEBPB), an inflammatory transcription factor, and enhances its transcriptional activity, escalating Alzheimer's disease-related gene expression and pathogenesis. The APP C586-695 fragment, but not full-length APP, strongly associates with CEBPB and elicits its nuclear translocation and augments the transcriptional activities on APP itself, MAPT (microtubule-associated protein tau), δ-secretase and inflammatory cytokine mRNA expression, finally triggering Alzheimer's disease pathology and cognitive disorder in a viral overexpression mouse model. Blockade of δ-secretase cleavage of APP by mutating the cleavage sites reduces its stimulatory effect on CEBPB, alleviating amyloid pathology and cognitive dysfunctions. Clearance of APP C586-695 from 5xFAD mice by antibody administration mitigates Alzheimer's disease pathologies and restores cognitive functions. Thus, in addition to the sequestration of amyloid-β, APP implicates in Alzheimer's disease pathology by activating CEBPB upon δ-secretase cleavage.

The bidirectional role of the JAK2/STAT3 signaling pathway and related mechanisms in cerebral ischemia-reperfusion injury

The Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway, a well-conserved and basic intracellular signaling cascade, is mostly inactivated under basal conditions, although it can be phosphorylated under extracellular stimulation; in addition, it can influence the transcription and expression of multiple genes involved in biological processes such as cellular growth, metabolism, differentiation, degradation and angiogenesis. The inflammatory response, apoptosis, oxidative stress and angiogenesis are the main factors involved in the pathogenesis of ischemic stroke. Numerous studies have confirmed that the JAK2/STAT3 axis can be activated rapidly by ischemic stress, which is closely related to the regulation of these important pathological processes. However, different opinions on the specific role of this signaling pathway remain. In this paper, we review and summarize previous studies on the JAK2/STAT3 pathway in ischemic stroke.

Spatially mapped single-cell chromatin accessibility

High-throughput single-cell epigenomic assays can resolve cell type heterogeneity in complex tissues, however, spatial orientation is lost. Here, we present single-cell combinatorial indexing on Microbiopsies Assigned to Positions for the Assay for Transposase Accessible Chromatin, or sciMAP-ATAC, as a method for highly scalable, spatially resolved, single-cell profiling of chromatin states. sciMAP-ATAC produces data of equivalent quality to non-spatial sci-ATAC and retains the positional information of each cell within a 214 micron cubic region, with up to hundreds of tracked positions in a single experiment. We apply sciMAP-ATAC to assess cortical lamination in the adult mouse primary somatosensory cortex and in the human primary visual cortex, where we produce spatial trajectories and integrate our data with non-spatial single-nucleus RNA and other chromatin accessibility single-cell datasets. Finally, we characterize the spatially progressive nature of cerebral ischemic infarction in the mouse brain using a model of transient middle cerebral artery occlusion.

Spatial orientation of cells in an interconnected network is lost in high-throughput single-cell epigenomic assays. Here the authors present sciMAP-ATAC to produce spatially resolved single-cell ATAC-seq data.

Homocysteine in Neurology: A Possible Contributing Factor to Small Vessel Disease

Homocysteine (Hcy) is a sulfur-containing amino acid generated during methionine metabolism, accumulation of which may be caused by genetic defects or the deficit of vitamin B12 and folate. A serum level greater than 15 micro-mols/L is defined as hyperhomocysteinemia (HHcy). Hcy has many roles, the most important being the active participation in the transmethylation reactions, fundamental for the brain. Many studies focused on the role of homocysteine accumulation in vascular or degenerative neurological diseases, but the results are still undefined. More is known in cardiovascular disease. HHcy is a determinant for the development and progression of inflammation, atherosclerotic plaque formation, endothelium, arteriolar damage, smooth muscle cell proliferation, and altered-oxidative stress response. Conversely, few studies focused on the relationship between HHcy and small vessel disease (SVD), despite the evidence that mice with HHcy showed a significant end-feet disruption of astrocytes with a diffuse SVD. A severe reduction of vascular aquaporin-4-water channels, lower levels of high-functioning potassium channels, and higher metalloproteinases are also observed. HHcy modulates the N-homocysteinylation process, promoting a pro-coagulative state and damage of the cellular protein integrity. This altered process could be directly involved in the altered endothelium activation, typical of SVD and protein quality, inhibiting the ubiquitin-proteasome system control. HHcy also promotes a constant enhancement of microglia activation, inducing the sustained pro-inflammatory status observed in SVD. This review article addresses the possible role of HHcy in small-vessel disease and understands its pathogenic impact.

Systematical Identification of the Protective Effect of Danhong Injection and BuChang NaoXinTong Capsules on Transcription Factors in Cerebral Ischemia Mice Brain

Cerebral ischemia has led to a high rate of both disability and mortality with massive healthcare costs. Although transcriptional regulation is typically mediated by different combinations of TFs, a combined regulatory unit to synergistically activate transcription has remained unclear in cerebral ischemia, especially in different drug treatments. In this study, TFs alterations after 6 h cerebral ischemic injury and repair were performed by a concatenated tandem array of consensus transcription factor response elements (catTFREs), and vital TFs were obtained by TFs-target imbalanced network. Drug intervention used Danhong injection (DHI) and BNC (BuChang NaoXinTong Capsules), which has been widely prescribed in Chinese herb medicine for the treatment of cerebrovascular and cardiovascular diseases. There were 198 TFs identified after 6 h MCAO operation, and six TFs (Sox2, Smad3, FoxO1, Creb1, Egr,1 and Smad4) were considered as critical TFs in response to cerebral ischemia. Moreover, Smad3 was identified as a hub TF among six vital TFs, and the transcription activity of Smad3 was further verified. These 6 TFs were all reversed by DHI or BNC, indicating different medications may regulate different transcription factors through TF synergy. Moreover, validation results indicated that Smad3 was a putative target TF for DHI and BNC-mediated protection against cerebral ischemia. The observations of the present study provide a fresh understanding of biomolecules and possible new avenues for therapeutic interventions, in addition to the new intervention pattern for different treatments for ischemia stroke.

Syringin exerts neuroprotective effects in a rat model of cerebral ischemia through the FOXO3a/NF-κB pathway

Inflammation plays an important role in the pathogenesis of cerebral ischemia. Syringin (SYR) is an active substance isolated from Acanthopanax senticosus plants, and possesses anti-inflammatory and neuroprotective properties. However, its effects on cerebral ischemic injury, as well as the underlying molecular events, are still unclear. The purpose of this study was to investigate the effect of SYR in a rat model of cerebral ischemia and address the related molecular mechanism. A middle cerebral artery occlusion/reperfusion model (MCAO) was used to simulate ischemic injury. SYR treatment clearly reduced the infarct volume, decreased cerebral water content, improved the neurological score, and attenuated neuronal death. Moreover, SYR decreased the expression of NF-κB, IL-1β, IL-6, TNF-α, and MPO, promoted FOXO3a phosphorylation and cytoplasmic retention, and inhibited the nuclear translocation of NF-κB. FOXO3a knockdown by RNA interference significantly prevented SYR-induced inhibition of NF-κB-mediated inflammation. Confocal microscopy revealed that SYR reduced NF-κB translocation to the nucleus, and FOXO3a silencing reversed this effect. Finally, immunofluorescence and CO-IP experiments showed that SYR promoted the interaction between FOXO3a and NF-κB. In conclusion, SYR exerted a protective effect against brain I/R injury by reducing the inflammation accompanying cerebral ischemia. This effect was mediated by the FOXO3a /NF-κB pathway.

CCL26 regulates the proportion of CD4+CD25+FOXP3+ Tregs and the production of inflammatory factors in peripheral blood mononuclear cells following acute ischemic stroke via the STAT5 pathway

Acute ischemic stroke (AIS) is the most common type of stroke. Recent studies have found that AIS is closely involved in the immune regulation function of regulatory T cells (Tregs). C-C motif chemokine ligand 26 (CCL26) is a member of the chemokine family that plays an essential role in cell activation, cell differentiation, lymphocyte homing, and inflammatory and immune responses. The present study aimed to investigate the role of CCL26 in the regulation of Tregs in AIS. Peripheral blood mononuclear cells (PBMCs) were incubated with a CCL26-neutralizing antibody. The proportion of cluster of differentiation (CD)4⁺CD25⁺ forkhead box P3 (FOXP3)⁺ Tregs was increased, and the expression of FOXP3, phosphorylated signal transducer and activator of transcription 5 (p-STAT5), and that of the immunosuppressive factors, interleukin (IL)-10 and transforming growth factor (TGF)-β1, was upregulated. Conversely, the expression of immune-promoting factors, such as tumor necrosis factor (TNF)-α and IL-6 was significantly downregulated. Further experiments using CCL26 recombinant protein-treated PBMCs revealed a decreased proportion of CD4⁺CD25⁺FOXP3⁺ Tregs and the downregulated expression of FOXP3, p-STAT5, TGF-β1 and IL-10. Moreover, the expression of immunostimulatory factors, such as CX3C chemokine receptor 1, TNF-α and IL-6 was significantly upregulated. On the whole, these results demonstrate that CCL26 regulates the proportion of CD4⁺CD25⁺FOXP3⁺ Tregs and the production of inflammatory factors in PBMCs following AIS via the STAT5 pathway.

Annexin A2 depletion exacerbates the intracerebral microhemorrhage induced by acute rickettsia and Ebola virus infections

Intracerebral microhemorrhages (CMHs) are small foci of hemorrhages in the cerebrum. Acute infections induced by some intracellular pathogens, including rickettsia, can result in CMHs. Annexin a2 (ANXA2) has been documented to play a functional role during intracellular bacterial adhesion. Here we report that ANXA2-knockout (KO) mice are more susceptible to CMHs in response to rickettsia and Ebola virus infections, suggesting an essential role of ANXA2 in protecting vascular integrity during these intracellular pathogen infections. Proteomic analysis via mass spectrometry of whole brain lysates and brain-derived endosomes from ANXA2-KO and wild-type (WT) mice post-infection with R. australis revealed that a variety of significant proteins were differentially expressed, and the follow-up function enrichment analysis had identified several relevant cell-cell junction functions. Immunohistology study confirmed that both infected WT and infected ANXA2-KO mice were subjected to adherens junctional protein (VE-cadherin) damages. However, key blood-brain barrier (BBB) components, tight junctional proteins ZO-1 and occludin, were disorganized in the brains from R. australis-infected ANXA2-KO mice, but not those of infected WT mice. Similar ANXA2-KO dependent CMHs and fragments of ZO-1 and occludin were also observed in Ebola virus-infected ANXA2-KO mice, but not found in infected WT mice. Overall, our study revealed a novel role of ANXA2 in the formation of CMHs during R. australis and Ebola virus infections; and the underlying mechanism is relevant to the role of ANXA2-regulated tight junctions and its role in stabilizing the BBB in these deadly infections.

The role of Toll-like receptor signaling pathways in cerebrovascular disorders: the impact of spreading depolarization

Cerebral vascular diseases (CVDs) are a group of disorders that affect the blood supply to the brain and lead to the reduction of oxygen and glucose supply to the neurons and the supporting cells. Spreading depolarization (SD), a propagating wave of neuroglial depolarization, occurs in different CVDs. A growing amount of evidence suggests that the inflammatory responses following hypoxic-ischemic insults and after SD plays a double-edged role in brain tissue injury and clinical outcome; a beneficial effect in the acute phase and a destructive role in the late phase. Toll-like receptors (TLRs) play a crucial role in the activation of inflammatory cascades and subsequent neuroprotective or harmful effects after CVDs and SD. Here, we review current data regarding the pathophysiological role of TLR signaling pathways in different CVDs and discuss the role of SD in the potentiation of the inflammatory cascade in CVDs through the modulation of TLRs.

Hispidulin Inhibits Neuroinflammation in Lipopolysaccharide-Activated BV2 Microglia and Attenuates the Activation of Akt, NF-κB, and STAT3 Pathway

Microglia, resident innate immune cells in central nervous system, regulates neuroinflammation and is associated with a variety of neuropathologies. The present study investigated the antineuroinflammatory effects of hispidulin (HPD), a naturally flavone compound, in lipopolysaccharide- (LPS-) stimulated BV2 microglia cells. The expression levels of nitric oxide (NO), reactive oxygen species (ROS), and pro-inflammatory factors were determined by the Griess method, flow cytometry, and enzyme-linked immunosorbent assay (ELISA). Western blotting was used to measure various transcription factors such as Akt, nuclear factor-kappa B (NF-κB), and signal transducer and activator of transcription 3 (STAT3) activities. Our experimental results demonstrated that HPD increased cell viability and reduced apoptosis in LPS-treated BV2 microglia cells. Moreover, HPD significantly reduced the levels of NO, ROS, inducible nitric oxide synthase (iNOS), cyclooxygenase- (COX-) 2, tumor necrosis factor- (TNF-) α, interleukin- (IL-) 1β, IL-6, and prostaglandin E2 (PGE2) in a dose-dependent manner. Phosphorylation of NF-κB/IκB, Akt, and STAT3 proteins expression by HPD was suppressed in LPS-induced BV2 microglial cells. We concluded that HPD may inhibit neuroinflammatory responses by inhibiting NF-κB pathway activation and ROS formation. These results propose that HPD has potential as anti-inflammatory agents against microglia-mediated neuroinflammatory disorders.

Molecular Mechanisms of Intermittent Fasting-induced Ischemic Tolerance

Diet is a significant factor in determining human well-being. Excessive eating and/or diets with higher than needed amounts of carbohydrates, salt, and fat are known to cause metabolic disorders and functional changes in the body. To compensate the ill effects, many designer diets including the Mediterranean diet, the Okinawa diet, vegetarian/vegan diets, keto diet, anti-inflammatory diet, and the anti-oxidant diet have been introduced in the past 2 decades. While these diets are either enriched or devoid of one or more specific components, a better way to control diet is to limit the amount of food consumed. Caloric restriction (CR), which involves limiting the amount of food consumed rather than eliminating any specific type of food, as well as intermittent fasting (IF), which entails limiting the time during which food can be consumed on a given day, have gained popularity because of their positive effects on human health. While the molecular mechanisms of these 2 dietary regimens have not been fully deciphered, they are known to prolong the life span, control blood pressure, and blood glucose levels. Furthermore, CR and IF were both shown to decrease the incidence of heart attack and stroke, as well as their ill effects. In particular, IF is thought to promote metabolic switching by altering gene expression profiles leading to reduced inflammation and oxidative stress, while increasing plasticity and regeneration.

Effect of curcumin on the inflammatory reaction and functional recovery after spinal cord injury in a hyperglycemic rat model

BACKGROUND CONTEXT

Curcumin has anti-inflammatory and antioxidant activities.

OBJECTIVE

This study aimed to investigate the effects of curcumin on the histological changes and functional recovery following spinal cord injury (SCI).

STUDY DESIGN

One hundred twenty-eight Sprague-Dawley rats were distributed into a sham, SCI only, SCI-hyperglycemia, and SCI-hyperglycemia-curcumin (200 mg/kg/day, i.p.) groups.

METHODS

SCI was induced using a clip at T9-10 and hyperglycemia was induced by streptozotocin (60-70 mg/kg, i.v.). Plasma malondialdehyde levels and superoxide dismutase activity was measured to determine oxidative stress. The activity of macrophages in the spinal cord after SCI was stained by the anti-CD68 antibody (ED-1). The tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-8 levels were measured by enzyme-linked immunosorbent assay and Western blot was used to verify the levels of mitogen-activated protein kinases and STAT3. The glial fibrillary acidic protein expression was evaluated by immunofluorescence analysis. Functional recovery was assessed according to the Basso, Beattie, and Bresnahan scale and histologic outcome was evaluated by the lesion volume and spared tissue area.

RESULTS

Superoxide dismutase activity increased, the malondialdehyde level decreased, and ED-1 macrophage marker level decreased in the SCI-hyperglycemia-curcumin group than in the SCI-hyperglycemia group at 2 weeks after SCI (p<.01). The SCI-hyperglycemia-curcumin group showed a statistically significant reduction in IL-6, IL-8, and TNF-α levels compared with the SCI-hyperglycemia group after SCI. The phosphorylated-extracellular signal-regulated kinase, phosphorylated-JNK, and phospho-p38 levels were significantly lower in the SCI-hypoglycemia-curcumin group than in the SCI-hypoglycemia group. The SCI-hyperglycemia-curcumin group showed a decrease in glial fibrillary acidic protein expression after SCI compared with the SCI-hyperglycemia group. The SCI-hyperglycemia-curcumin group showed a lower lesion volume, higher spared tissue, and better functional recovery than the SCI-hyperglycemia group.

CONCLUSIONS

Curcumin may have a potential neuroprotective effect in SCI with hyperglycemia.

CLINICAL SIGNIFICANCE

Curcumin decreased the inflammatory response and decreased astrogliosis and improved the functional recovery and histologic outcomes in SCI with hyperglycemia.

Progress in the emerging role of selenoproteins in cardiovascular disease: focus on endoplasmic reticulum-resident selenoproteins

Cardiovascular diseases represent one of the most important health problems of developed countries. One of the main actors involved in the onset and development of cardiovascular diseases is the increased production of reactive oxygen species that, through lipid peroxidation, protein oxidation and DNA damage, induce oxidative stress and cell death. Basic and clinical research are ongoing to better understand the endogenous antioxidant mechanisms that counteract oxidative stress, which may allow to identify a possible therapeutic targeting/application in the field of stress-dependent cardiovascular pathologies. In this context, increasing attention is paid to the glutathione/glutathione-peroxidase and to the thioredoxin/thioredoxin-reductase systems, among the most potent endogenous antioxidative systems. These key enzymes, belonging to the selenoprotein family, have a well-established function in the regulation of the oxidative cell balance. The aim of the present review was to highlight the role of selenoproteins in cardiovascular diseases, introducing the emerging cardioprotective role of endoplasmic reticulum-resident members and in particular one of them, namely selenoprotein T or SELENOT. Accumulating evidence indicates that the dysfunction of different selenoproteins is involved in the susceptibility to oxidative stress and its associated cardiovascular alterations, such as congestive heart failure, coronary diseases, impaired cardiac structure and function. Some of them are under investigation as useful pathological biomarkers. In addition, SELENOT exhibited intriguing cardioprotective effects by reducing the cardiac ischemic damage, in terms of infarct size and performance. In conclusion, selenoproteins could represent valuable targets to treat and diagnose cardiovascular diseases secondary to oxidative stress, opening a new avenue in the field of related therapeutic strategies.

Cornel iridoid glycoside exerts a neuroprotective effect on neuroinflammation in rats with brain injury by inhibiting NF-κB and STAT3

Traumatic brain injury leads to problems with movement and cognitive deficits and has a high mortality rate. Cornel iridoid glycoside, the active ingredient of Cornus officinalis, has been reported to ameliorate apoptosis and inflammation in rats. We investigated the therapeutic effect of cornel iridoid glycoside on neuroinflammation in rats with brain injury. Rats were treated with cornel iridoid glycoside, and then measurements of antioxidant, proinflammatory marker, and NF-κB and STAT3 mRNA and protein levels, as well as a histopathologic analysis, were conducted. Cornel iridoid glycoside significantly reduced lipid peroxidation and TNF-α and IL-6 levels but increased the levels of antioxidants. In addition, cornel iridoid glycoside significantly decreased the expression of NF-κB and STAT3. Histopathological analyses showed that cornel iridoid glycoside reduced the severity of neuroinflammation and apoptosis. Therefore, cornel iridoid glycoside significantly ameliorated neuroinflammation by reducing lipid peroxidation and proinflammatory marker levels and increasing antioxidant levels in rats with brain injury.

Identification of key transcription factors associated with cerebral ischemia‑reperfusion injury based on gene‑set enrichment analysis

Cerebral ischemia‑reperfusion injury (CIRI) usually causes detrimental complications following reperfusion therapy in stroke patients. The present study systematically investigated the regulatory mechanism involved in the pathogenesis of CIRI using gene set enrichment analysis of the transient middle cerebral artery occlusion mouse stroke model. The results revealed a total of 13 CIRI‑related transcription factors (TFs), including CCAAT enhancer binding protein b (Cebpb), Cebpa, early growth response‑1, Fos, Rela, Jund, signal transduction and activator of transcription 5a/b, transformation related protein 53, GLI family zinc finger 2 (Gli2), Sp3, TF AP‑2 α (Tfap2a) and spleen focus forming virus proviral integration oncogene (Spi1). To the best of our knowledge, five TFs (Cebpa, Gli2, Sp3, Tfap2a and Spi1) were the first to be reported associated with CIRI in the present study. The five novel CIRI‑related TFs were mainly associated with pathways of inflammation and responses to reperfusion, including the tumor necrosis factor signaling pathway (Gli2, Spi1 and Tfap2a, P=0.0035, 0.0035 and 0.048, respectively), interleuking‑17 signaling pathway (Cebpa, Gli2, Sp3, Spi1 and Tfap2a, P=0.019, 0.047, 0.019, 0.035 and 0.005, respectively) and fluid shear stress and atherosclerosis (Gli2, Sp3, Spi1 and Tfap2a, P=0.047, 0.046, 0.013 and 0.003, respectively). These results may improve understanding of the potential molecular mechanism underlying the pathogenesis of CIRI at the genome‑wide level.

Mesenchymal Stromal Cell Derived Extracellular Vesicles Reduce Hypoxia-Ischaemia Induced Perinatal Brain Injury

BACKGROUND

Neonatal hypoxic-ischemic (HI) insult is a leading cause of disability and death in newborns, with therapeutic hypothermia being the only currently available clinical intervention. Thus there is a great need for adjunct and novel treatments for enhanced or alternative post-HI neuroprotection. Extracellular vesicles (EVs) derived from mesenchymal stromal/stem cells (MSCs) have recently been shown to exhibit regenerative effects in various injury models. Here we present findings showing neuroprotective effects of MSC-derived EVs in the Rice-Vannucci model of severe HI-induced neonatal brain insult.

METHODS

Mesenchymal stromal/stem cell-derived EVs were applied intranasally immediately post HI-insult and behavioral outcomes were observed 48 h following MSC-EV treatment, as assessed by negative geotaxis. Brains were thereafter excised and assessed for changes in glial responses, cell death, and neuronal loss as markers of damage at 48 h post HI-insult.

RESULTS

Brains of the MSC-EV treated group showed a significant decrease in microglial activation, cell death, and percentage tissue volume loss in multiple brain regions, compared to the control-treated groups. Furthermore, negative geotaxis test showed improved behavioral outcomes at 48 h following MSC-EV treatment.

CONCLUSION

Our findings highlight the clinical potential of using MSC-derived EVs following neonatal hypoxia-ischaemia.

Prostate cancer promotes a vicious cycle of bone metastasis progression through inducing osteocytes to secrete GDF15 that stimulates prostate cancer growth and invasion

Bone is the most frequent site of prostate cancer (PCa) metastasis; however, little is known about the role of the most common cell in bone, the osteocyte (OCy), in cancer biology. In this study we explored the crosstalk between PCa cells and OCys to determine if it contributes to PCa progression. PCa cells induced OCys to promote PCa proliferation, migration and invasion. A chemokine screen revealed that PCa cell induced OCys to produce growth-derived factor 15 (GDF15). Knockdown of GDF15 in OCys demonstrated that PCa cells conferred the ability on OCys to promote PCa proliferation, migration and invasion through GDF15. Consistent with this finding was the observation that the GDF15 receptor, GFRAL, was expressed on multiple PCa cell lines. Transcription factor array screening of PCa cells exposed to OCys with or without knockdown of GDF15 revealed that GDF15 in OCys promoted early growth response 1 (EGR1) expression in the PCa cells. Knockdown of EGR1 expression in PCa cells revealed it was required for the OCy-derived GDF15-mediated induction of in vitro PCa cell proliferation, migration and invasion. Subcutaneous co-injection of PCa cells and OCys into mice revealed that OCys promoted tumor growth in vivo, which was diminished by knockdown of GDF15 in the OCys. Knockdown of GDF15 in the tibiae diminished growth of PCa cancer cells injected into the tibiae, which was accompanied by decreased tumor cell proliferation and EGR1 expression. These results shed light on a novel mechanism through which PCa cells educate OCys to promote progression of PCa bone metastasis. They also suggest that targeting of GDF15-based and EGR1-based signaling pathways should be further explored for their potential to diminish progression of PCa bone metastasis.

Safflower Yellow B Protects Brain against Cerebral Ischemia Reperfusion Injury through AMPK/NF-kB Pathway

Inflammation had showed its important role in the pathogenesis of cerebral ischemia and secondary damage. Safflower yellow B (SYB) had neuroprotective effects against oxidative stress-induced brain injuries, but the mechanisms were still largely unknown to us. In this study, we tried to investigate the anti-inflammation effects of SYB and the possible roles of AMPK/NF-κB signaling pathway on these protective effects. In vivo, brain ischemia/reperfusion (I/R) was induced by transient middle cerebral artery occlusion for 2 h and reperfusion for 20 h. Neurofunctional evaluation, infarction area, and brain water contents were measured. Brain injury markers and inflammatory cytokines levels were measured by ELISA kits. In vitro, cell viability, apoptosis, and LDH leakage were measured after I/R in PC12 cells. The expression and phosphorylation levels of AMPK, NF-κB p65, and P-IκB-α in cytoplasm and nuclear were measured by Western blotting. SiRNA experiment was performed to certify the role of AMPK. The results showed SYB reduced infarct size, improved neurological outcomes, and inhibited brain injury after I/R. In vitro test, SYB treatment alleviated PC12 cells injury and apoptosis and inhibited the inflammatory cytokines (IL-1, IL-6, TNF-α, and COX-2) in a dose-dependent manner. SYB treatment induced AMPK phosphorylation and inhibited NF-κB p65 nuclear translocation both in brain and in PC12 cells. Further studies also showed that the inhibition of NF-κB activity of SYB was through AMPK. In conclusion, SYB protected brain I/R injury through reducing expression of inflammatory cytokines and this effect might be partly due to the inhibition of NF-κB mediated by AMPK.

ESE1 expression correlates with neuronal apoptosis in the hippocampus after cerebral ischemia/reperfusion injury

Epithelial-specific ETS-1 (ESE1), a member of the ETS transcription factor family, is widely expressed in multiple tissues and performs various functions in inflammation. During neuroinflammation, ESE1 promotes neuronal apoptosis; however, the expression and biological functions of ESE1 remain unclear after cerebral ischemia/reperfusion. We performed in vivo and in vitro experiments to explore the role of ESE1 in cerebral ischemic injury. A modified four vessel occlusion method was used in adult Sprague-Dawley rats. At 6, 12, 24, 48, and 72 hours after model induction, the hippocampus was collected for analysis. Western blot assays and immunohistochemistry showed that the expression of ESE1, phosphorylated p65 and active caspase-3 was significantly up-regulated after ischemia. Double immunofluorescence staining indicated that ESE1 and NeuN were mostly co-located in the hippocampus after ischemia. Furthermore, ESE1 was also co-expressed with active caspase-3. PC12 cells were stimulated with cobalt chloride (CoCl₂) to establish a chemical hypoxia model. After ESE1 knockdown by siRNA for 6 hours, cell viability was detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assays. The levels of ESE1, phosphorylated p65 and active caspase-3 were also remarkably increased in PC12 cells after CoCl₂ stimulation. After ESE1 knockdown, PC12 cell viability was increased after hypoxia. siRNA knockdown of ESE1 decreased the level of p-p65 and active caspase-3 after CoCl₂ stimulation. These data reveal that ESE1 levels are elevated in the hippocampus after cerebral ischemia/reperfusion injury. This may play a role in neuronal apoptosis via activation of the nuclear factor-κB pathway.

The Traditional Chinese Medicine MLC901 inhibits inflammation processes after focal cerebral ischemia

Inflammation is considered as a major contributor to brain injury following cerebral ischemia. The therapeutic potential of both MLC601/MLC901, which are herbal extract preparations derived from Chinese Medicine, has been reported both in advanced stroke clinical trials and also in animal and cellular models. The aim of this study was to investigate the effects of MLC901 on the different steps of post-ischemic inflammation in focal ischemia in mice. In vivo injury was induced by 60 minutes of middle cerebral artery occlusion (MCAO) followed by reperfusion. MLC901 was administered in post-treatment 90 min after the onset of ischemia and once a day during reperfusion. MLC901 treatment resulted in a reduction in infarct volume, a decrease of Blood Brain Barrier leakage and brain swelling, an improvement in neurological scores and a reduction of mortality rate at 24 hours after MCAO. These beneficial effects of MLC901 were accompanied by an inhibition of astrocytes and microglia/macrophage activation, a drastically decreased neutrophil invasion into the ischemic brain as well as by a negative regulation of pro-inflammatory mediator expression (cytokines, chemokines, matrix metalloproteinases). MLC901 significantly inhibited the expression of Prx6 as well as the transcriptional activity of NFκB and the activation of Toll-like receptor 4 (TLR4) signaling, an important pathway in the immune response in the ischemic brain. MLC901 effects on the neuroinflammation cascade induced by cerebral ischemia probably contribute, in a very significant way, in its potential therapeutic value.

Comparative transcriptome of neurons after oxygen-glucose deprivation: Potential differences in neuroprotection versus reperfusion

In the context of ischemic stroke, rescuing neurons can be theoretically achieved with either reperfusion or neuroprotection. Reperfusion works via the rapid restoration of oxygen and glucose delivery. Neuroprotection comprises molecular strategies that seek to block excitotoxicity, oxidative stress or various cell death pathways. Here, we propose the hypothesis that neurons rescued with reperfusion are different from neurons rescued with molecular neuroprotection. Neurons were subjected to oxygen-glucose deprivation (OGD) and then treated with "in vitro reperfusion" (i.e. energetic rescue via restoration of oxygen and glucose) or Z-VADfmk (to block apoptosis) or MK-801 (to block excitotoxicity). Levels of injury were titrated so that equivalent levels of neuronal salvage were achieved with reperfusion or neuroprotection. Gene arrays showed that OGD significantly altered the transcriptomic profiles of surviving neurons. Pathway analysis confirmed that a large spectrum of metabolic, inflammation, and signaling genes were perturbed. In spite of the fact that equal levels of neuronal salvage were achieved, energetic rescue renormalized the transcriptomic profiles in surviving neurons to a larger degree compared to neuroprotection with either Z-VADfmk or MK-801. These findings suggest that upstream reperfusion may bring salvaged neurons back "closer to normal" compared to downstream molecular neuroprotection.