Organelle-Specific Molecular Remodeling in Mouse Brain Microvessels After Ischemic Stroke

Ginkgolide K promotes angiogenesis in a middle cerebral artery occlusion mouse model via activating JAK2/STAT3 pathway

Intravenous miR-30c therapy confers dual neurovascular protection and improves long-term recovery after ischemic stroke.

BackgroundThe pathophysiology of ischemic stroke is not fully elucidated. Upregulation of FKBP5 in brain ischemia/reperfusion injury has been found to be associated with the severity of ischemic and reperfusion damage. However, its specific role in ischemic stroke progression remains unclear.MethodsA total of 40 ischemic stroke patients and 40 age- and sex-matched healthy donors (HDs) were enrolled in this work to evaluate the expression of FKBP5, the formation of neutrophil extracellular trap (NET), and the correlation between NET and stroke. Moreover, transient middle cerebral artery occlusion (tMCAO) mouse model with 60 min occlusion (n = 15/group) was treated with CI-amidine to demonstrate the effect of NET on the stroke-related brain injury. Primary neurons were isolated from mouse brain tissue to evaluated the effect of NET on neuronal apoptosis through flow cytometry the TUNEL assays. In addition, BV2 microglial cells were transfected with FKBP5 overexpression and knockdown vectors. The microglial cells polarization, neutrophil NETs formation, and the underlying molecular action mechanism were measured. For specific methods: detected the levels of H3cit, MPO-DNA, IL-1β, IL-10, TNFα, and iNOS by ELISA; Pathological staining was viewed for the neuronal morphological changes; flow cytometry and TUNEL staining were viewed for the neuronal cell apoptosis; detected the protein levels of FKBP5, CD206, CCL5, and MAPK pathway by western blot.ResultsIn this study, we observed significant upregulation of FKBP5 in ischemic stroke patients, which was associated with increased expression of NET markers, such as H3cit and MPO-DNA complexes. This upregulation correlated with stroke severity and outcomes. In a transient middle cerebral artery occlusion (tMCAO) mouse model, treatment with the NET inhibitor CI-amidine significantly reduced brain injury, infarct size, and NET marker levels, suggesting therapeutic potential in targeting NETs. We further found that FKBP5 modulates microglial polarization towards a pro-inflammatory M1 phenotype and promotes NET formation. FKBP5 interacts with CCL5, enhancing MAPK pathway activation and increasing pro-inflammatory cytokine production, including TNF-α and IL-1β. Intervention with the MAPK pathway inhibitor AZD6244 effectively inhibited these effects.ConclusionsThe current findings suggest that FKBP5 might modulate CCL5-mediate p38 MAPK signaling and NET formation, thereby contributing to post-stroke neuroinflammation and neuronal apoptosis. Further prospective research is needed to verify the potential of FKBP5 as therapeutic targets for ischemic stroke treatment.

Celastrol plays a significant role in cerebral ischemia-reperfusion injury. Although previous studies have confirmed that celastrol post-treatment has a protective effect on ischemic stroke, the therapeutic effect of celastrol on ischemic stroke and the underlying molecular mechanism remain unclear. In the present study, focal transient cerebral ischemia was induced by transient middle cerebral artery occlusion (tMCAO) in mice and celastrol was administered immediately after reperfusion. We performed lncRNA and mRNA analysis in the ischemic hemisphere of adult mice with celastrol post-treatment through RNA-Sequencing (RNA-Seq). A total of 50 differentially expressed lncRNAs (DE lncRNAs) and 696 differentially expressed mRNAs (DE mRNAs) were identified between the sham and tMCAO group, and a total of 544 DE lncRNAs and 324 DE mRNAs were identified between the tMCAO and tMCAO + celastrol group. Bioinformatic analysis was done on the identified deregulated genes through gene ontology (GO) analysis, KEGG pathway analysis and network analysis. Pathway analysis indicated that inflammation-related signaling pathways played vital roles in the treatment of ischemic stroke by celastrol. Four DE lncRNAs and 5 DE mRNAs were selected for further validation by qRT-PCR in brain tissue, primary neurons, primary astrocytes, and BV2 cells. The results of qRT-PCR suggested that most of selected differentially expressed genes showed the same fold change patterns as those in RNA-Seq results. Our study suggests celastrol treatment can effectively reduce cerebral ischemia-reperfusion injury. The bioinformatics analysis of lnRNAs and mRNAs profiles in the ischemic hemisphere of adult mice provides a new perspective in the neuroprotective effects of celastrol, particularly with regards to ischemic stroke.

Background and aimsPreclinical and clinical evidence supports the value of nutraceuticals as prophylactic or adjuvant therapeutics to reduce stroke risk or to improve post-stroke recovery. Given the beneficial properties of xantophyll carotenoids, we aimed at assessing the putative neuroprotective effects of zeaxanthin, evaluating its anti-inflammatory and anti-oxidant properties in vitro and in vivo. Methods and resultsExposure to zeaxanthin (25 μM for 24 h) reverted the elevation of inducible nitric oxide synthase (iNOS) expression prompted by tumor necrosis factor (TNF)-α in macrophages from mouse bone marrow. In mice subjected to transient (30-min) middle cerebral artery occlusion (MCAo), oral pre-treatment with zeaxanthin (2 mg/kg, 48 h, 24 h and 1 h before MCAo) prevented the elevation of serum levels of reactive oxygen species induced by the ischemic insult, while it did not affect the reduction of antioxidant barrier efficiency. Analysis of lipid peroxidation showed a significant increase in hydroperoxide level in the brain of mice subjected to MCAo, and the latter effect was inhibited by pretreatment with zeaxanthin. Finally, we originally demonstrated that oral administration of zeaxanthin significantly reduced neurological deficits and brain damage caused by transient MCAo in mice. ConclusionsOur data, in combination with the evidence that zeaxanthin is a well-tolerated carotenoid, strengthen the nutritional value of this xanthophyll in the prevention of ischemic stroke injury.

Background: The role of each nitric oxide synthase (NOS) isoform in cerebral infarction has been studied in individual NOS isoform-deficient mice. It has been reported that, in a model of middle cerebral artery occlusion (MCAO), neuronal and inducible NOSs exacerbate cerebral infarction, whereas endothelial NOS conversely alleviates it. Although the role of the whole NOSs system in cerebral infarction has been examined in pharmacological studies with non-selective NOS inhibitors, the results are quit inconsistent, possibly because of non-specificity of the agents. In this study, we addressed this point in mice in which all three NOS genes are completely disrupted. Method and Results: We newly generated triple NOSs -/- mice and wild-type littermates by crossbreeding single NOS -/- mice. Transient (1 hour) or permanent MCAO was performed in male triple NOSs -/- and wild-type mice at 8-12 weeks of age (n=8-11). There was no anatomical difference in the structure of cerebral arteries between the triple NOSs -/- and the wild-type mice. Reductions in cerebral blood flow during MCAO were also comparable between the two genotypes. However, cerebral infarct size at 24 hours after transient MCAO was markedly reduced in the triple NOSs -/- genotype as compared with the wild-type genotype ( P <0.05). Cerebral infarct size at 24 hours after permanent MCAO was also markedly smaller in the triple NOSs -/- than in the wild-type genotype ( P <0.05). In addition, neurological deficit was significantly less and the survival rate was significantly better in the triple NOSs -/- genotype compared with the wild-type genotype (each P <0.05). Importantly, 3-nitrotyrosine protein levels (a marker of peroxynitrite production) in the cerebral infarct region were significantly decreased in the triple NOSs -/- genotype as compared with the wild-type genotype ( P <0.05), suggesting an involvement of decreased oxidative stress. Conclusions: These results provide the first evidence that complete disruption of all NOS genes markedly reduces cerebral infarct size after MCAO in mice, demonstrating a novel injurious role of the entire NOSs system in the pathogenesis of cerebral infarction. Inhibition of the NOSs system may be a new therapeutic option in the treatment of cerebral infarction.

Background: The role of each nitric oxide synthase (NOS) isoform in the pathogenesis of cerebral infarction has been studied in individual NOS isoform-deficient mice. It has been reported that, in a model of middle cerebral artery occlusion (MCAO), neuronal and inducible NOSs exacerbate cerebral infarction, whereas endothelial NOS conversely alleviates cerebral infarction. Although the role of the whole NOSs system in cerebral infarction has been examined in pharmacological studies with non-selective NOS inhibitors, the results are quit inconsistent, possibly because of non-specificity of the agents. In this study, we addressed this point in mice in which all three NOS genes are completely disrupted. Method and Results: We newly generated triple NOSs-deficient mice and wild-type littermates by crossbreeding single NOS -/- mice. Transient (1 hour) and permanent MCAO was performed in male triple NOSs -/- and wild-type mice at 8-12 weeks of age (n=9-11). Cerebral infarct size was evaluated by triphenyltetrazolium chloride (TTC) staining. There was no anatomical difference in the structure of cerebral arteries between the triple NOSs -/- and wild-type mice (n=3 each). Reductions in cerebral blood flow during MCAO were identical between the two mice. However, cerebral infarct size at 24 hours after transient MCAO was markedly smaller in the triple NOSs -/- than in the wild-type mice ( P <0.05, n=8-12). Cerebral infarct size at 24 hours after permanent MCAO was also markedly decreased in the triple NOSs -/- mice as compared with the wild-type mice ( P <0.05, n=8-10). In addition, neurological deficit was significantly less and the survival rate was significantly better in the triple NOSs -/- mice compared with the wild-type mice (both P <0.05, n=8-12). Conclusions: These results provide the first evidence that complete disruption of all NOS genes markedly reduces cerebral infarct size after MCAO in mice, demonstrating a novel injurious role of the entire NOSs system in cerebral infarction. Inhibition of the NOSs system may be a novel therapeutic option in the treatment of cerebral infarction.

Gluten proteins are the major storage protein fraction in the mature wheat grain. They are restricted to the starchy endosperm, which defines the viscoelastic properties of wheat dough. The synthesis of these storage proteins is controlled by the endoplasmic reticulum (ER) and is directed into the vacuole via the Golgi apparatus. In the present study, transcriptome analysis was used to explore the potential mechanism within critical stages of grain development of wheat cultivar "Shaannong 33" and its sister line used as the control (CK). Samples were collected at 10 DPA (days after anthesis), 14 DPA, 20 DPA, and 30 DPA for transcriptomic analysis. The comparative transcriptome analysis identified that a total of 18,875 genes were differentially expressed genes (DEGs) between grains of four groups "T10 vs. CK10, T14 vs. CK14, T20 vs. CK20, and T30 vs. CK30", including 2824 up-regulated and 5423 down-regulated genes in T30 vs. CK30. Further, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment highlighted the maximum number of genes regulating protein processing in the endoplasmic reticulum (ER) during grain enlargement stages (10-20 DPA). In addition, KEGG database analysis reported 1362 and 788 DEGs involved in translation, ribosomal structure, biogenesis, flavonoid biosynthesis pathway and intracellular trafficking, secretion, and vesicular transport through protein processing within ER pathway (ko04141). Notably, consistent with the higher expression of intercellular storage protein trafficking genes at the initial 10 DPA, there was relatively low expression at later stages. Expression levels of nine randomly selected genes were verified by qRT-PCR, which were consistent with the transcriptome data. These data suggested that the initial stages of "cell division" played a significant role in protein quality control within the ER, thus maintaining the protein quality characteristics at grain maturity. Furthermore, our data suggested that the protein synthesis, folding, and trafficking pathways directed by a different number of genes during the grain enlargement stage contributed to the observed high-quality characteristics of gluten protein in Shaannong 33 (Triticum aestivum L.).

The blood-brain barrier (BBB) is a selectively permeable cerebrovascular endothelial barrier that maintains homeostasis between the periphery and the central nervous system. BBB disruption is a consequence of ischemic stroke and BBB permeability can be altered by infection/inflammation, but the complex cellular and molecular changes that result in this BBB alteration need to be elucidated to determine mechanisms. Infection mimic (lipopolysaccharide) challenge on infarct volume, BBB permeability, infiltrated neutrophils, and functional outcomes after murine transient middle cerebral artery occlusion in vivo; mitochondrial evaluation of cerebrovascular endothelial cells challenged by lipopolysaccharide in vitro; pharmacological inhibition of mitochondria on BBB permeability in vitro and in vivo; the effects of mitochondrial inhibitor on BBB permeability, infarct volume, and functional outcomes after transient middle cerebral artery occlusion. We report here that lipopolysaccharide worsens ischemic stroke outcome and increases BBB permeability after transient middle cerebral artery occlusion in mice. Furthermore, we elucidate a novel mechanism that compromised mitochondrial function accounts for increased BBB permeability as evidenced by: lipopolysaccharide-induced reductions in oxidative phosphorylation and subunit expression of respiratory chain complexes in cerebrovascular endothelial cells, a compromised BBB permeability induced by pharmacological inhibition of mitochondrial function in cerebrovascular endothelial cells in vitro and in an in vivo animal model, and worsened stroke outcomes in transient middle cerebral artery occlusion mice after inhibition of mitochondrial function. We concluded that mitochondria are key players in BBB permeability. These novel findings suggest a potential new therapeutic strategy for ischemic stroke by endothelial cell mitochondrial regulation.

The folding of glycoproteins in the endoplasmic reticulum (ER) depends on a quality control mechanism mediated by the calnexin/calreticulin cycle. During this process, continuous glucose trimming and UDP-glucose-dependent re-glucosylation of unfolded glycoproteins takes place. To ensure proper folding, increases in misfolded proteins lead to up-regulation of the components involved in quality control through a process known as the unfolded protein response (UPR). Reglucosylation is catalyzed by the ER lumenal located enzyme UDP-glucose glycoprotein glucosyltransferase, but as UDP-glucose is synthesized in the cytosol, a UDP-glucose transporter is required in the calnexin/calreticulin cycle. Even though such a transporter has been hypothesized, no protein playing this role in the ER yet has been identified. Here we provide evidence that AtUTr1, a UDP-galactose/glucose transporter from Arabidopsis thaliana, responds to stimuli that trigger the UPR increasing its expression around 9-fold. The accumulation of AtUTr1 transcript is accompanied by an increase in the level of the AtUTr1 protein. Moreover, subcellular localization studies indicate that AtUTr1 is localized in the ER of plant cells. We reasoned that an impairment in AtUTr1 expression should perturb the calnexin/calreticulin cycle leading to an increase in misfolded protein and triggering the UPR. Toward that end, we analyzed an AtUTr1 insertional mutant and found an up-regulation of the ER chaperones BiP and calnexin, suggesting that these plants may be constitutively activating the UPR. Thus, we propose that in A. thaliana, AtUTr1 is the UDP-glucose transporter involved in quality control in the ER.

Characterization of the inflammatory post-ischemic tissue by full volumetric analysis of a multimodal imaging dataset

Investigation of long-term metabolic alteration after stroke in tMCAO (transient middle cerebral artery occlusion) mouse model using metabolomics approach

Circular RNAs (circRNAs) are highly expressed in the CNS and regulate physiological and pathophysiological processes. However, the potential role of circRNAs in stroke remains largely unknown. Here, we show that the circRNA DLGAP4 (circDLGAP4) functions as an endogenous microRNA-143 (miR-143) sponge to inhibit miR-143 activity, resulting in the inhibition of homologous to the E6-AP C-terminal domain E3 ubiquitin protein ligase 1 expression. circDLGAP4 levels were significantly decreased in the plasma of acute ischemic stroke patients (13 females and 13 males) and in a mouse stroke model. Upregulation of circDLGAP4 expression significantly attenuated neurological deficits and decreased infarct areas and blood-brain barrier damage in the transient middle cerebral artery occlusion mouse stroke model. Endothelial-mesenchymal transition contributes to blood-brain barrier disruption and circDLGAP4 overexpression significantly inhibited endothelial-mesenchymal transition by regulating tight junction protein and mesenchymal cell marker expression. Together, the results of our study are illustrative of the involvement of circDLGAP4 and its coupling mechanism in cerebral ischemia, providing translational evidence that circDLGAP4 serves as a novel therapeutic target for acute cerebrovascular protection.SIGNIFICANCE STATEMENT Circular RNAs (circRNAs) are involved in the regulation of physiological and pathophysiological processes. However, whether circRNAs are involved in ischemic injury, particularly cerebrovascular disorders, remains largely unknown. Here, we demonstrate a critical role for circular RNA DLGAP4 (circDLGAP4), a novel circular RNA originally identified as a sponge for microRNA-143 (miR-143), in ischemic stroke outcomes. Overexpression of circDLGAP4 significantly attenuated neurological deficits and decreased infarct areas and blood-brain barrier damage in the transient middle cerebral artery occlusion mouse stroke model. To our knowledge, this is the first report describing the efficacy of circRNA injection in an ischemic stroke model. Our investigation suggests that circDLGAP4 may serve as a novel therapeutic target for acute ischemic injury.

Cerebral ischemia-reperfusion damages local brain tissue and impairs brain function, but its specific pathogenesis is still uncertain. Recent studies have clarified circPUM1 is aberrantly elevated in cerebral ischemia-reperfusion injury; however, circPUM1ʹs function in cerebral ischemia-reperfusion-induced neuronal injury remains ambiguous. The results illustrated circPUM1 and DEAD-box helicase 5 were decreased, but microRNA-340-5p was elevated in transient middle cerebral artery occlusion mice and oxygen glucose deprivation/reoxygenation-treated SH-SY5Y cells. Knockdown of circPUM1 aggravated the neuronal injury in transient middle cerebral artery occlusion mice and motivated glial cell activation, neuronal apoptosis and inflammation. Enhancing circPUM1 restrained oxygen glucose deprivation/reoxygenation-induced SH-SY5Y cell apoptosis, the release of lactate dehydrogenase and inflammatory factors, and activation of nuclear factor-kappaB pathway, while elevating microRNA-340-5p aggravated oxygen glucose deprivation/reoxygenation-induced cell damage. Functional rescue experiments exhibited that the impacts of knockdown or enhancement of circPUM1 were turned around by microRNA-340-5p downregulation and DEAD-box helicase 5 silencing, respectively. Moreover, it was demonstrated that circPUM1 competitively adsorbed microRNA-340-5p to mediate DEAD-box helicase 5. All in all, this study clarifies that circPUM1 mitigates cerebral ischemia-reperfusion-induced neuronal injury by targeting the microRNA-340-5p/DEAD-box helicase 5 axis.

Chloroplast lipids are synthesized via two distinct pathways: the plastidic pathway and endoplasmic reticulum (ER) pathway. We previously reported that the contribution of the two pathways toward chloroplast development is different between mesophyll cells and guard cells in Arabidopsis leaf tissues and that the ER pathway plays a major role in guard cell chloroplast development. However, little is known about the contribution of the two pathways toward chloroplast development in other tissue cells, and in this study, we focused on root cells. Chloroplast development is normally repressed in roots but can be induced when the roots are detached from the shoots (root greening). We found that, similar to guard cells, root cells exhibit a higher proportion of glycolipid from the ER pathway. Root greening was repressed in the gles1 mutant, which has a defect in ER-to-plastid lipid transportation via the ER pathway, while normal root greening was observed in the ats1 mutant, whose plastidic pathway is blocked. Lipid analysis revealed that the gles1 mutation caused drastic decrease in the ER-derived glycolipids in roots. Furthermore, the gles1 detached roots showed smaller chloroplasts containing less starch than WT. These results suggest that the ER pathway has a significant contribution toward chloroplast development in the root cells.