Protective effect of 4-Methoxy benzyl alcohol on the neurovascular unit after cerebral ischemia reperfusion injury

Unveiling the Significance of Peroxiredoxin 6 in Central Nervous System Disorders

Peroxiredoxin 6 (Prdx6), a unique 1-Cys member of the peroxiredoxin family, exhibits peroxidase activity, phospholipase activity, and lysophosphatidylcholine acyltransferase (LPCAT) activity. Prdx6 has been known to be an important enzyme for the maintenance of lipid peroxidation repair, cellular metabolism, inflammatory signaling, and antioxidant damage. Growing research has demonstrated that the altered activity of this enzyme is linked with various pathological processes including central nervous system (CNS) disorders. This review discusses the distinctive structure, enzyme activity, and function of Prdx6 in different CNS disorders, as well as emphasizing the significance of Prdx6 in neurological disorders.

Pharmacokinetics of 4-Hydroxybenzaldehyde in Normal and Cerebral Ischemia-Reperfusion Injury Rats Based on Microdialysis Technique

AIM

4-Hydroxybenzaldehyde (4-HBd) is used for the treatment of headaches, dizziness, and convulsions. The objective of this study was to characterize the pharmacokinetics of 4-HBd in cerebral ischemia-reperfusion injury (CIRI) rats by microdialysis technology with high-performance liquid chromatography with diode-array detection (HPLC-DAD) and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS).

METHODS

Microdialysis was used to collect blood, feces, and urine of normal and CIRI model rats. Pharmacokinetic parameters were determined using HPLC-DAD and 4-HBd metabolites were determined using UPLC-MS.

RESULTS

After gavage of 4-HBd in normal and middle cerebral artery occlusion/reperfusion (MCAO/R) rats, it was widely distributed to all tissues (heart, liver, spleen, lung, kidney, and brain) in both the equilibrium and elimination phases, and the distribution pattern was basically the same; the highest concentration was found in the brain. The absolute bioavailability of 4-HBd was 5.33%; however, after intragastric administration in normal and MCAO/R rats, fecal and urinary excretion of 4-HBd accounted for 0.02% and 0.01% and for 0.01% and 0.03% of the dosage, respectively. Furthermore, 4-HBd was rapidly metabolized into 4-hydroxybenzoic acid (4-HBA) after administration in both the control and MCAO/R groups. Compared with the control, the peak time of 4-HBd plasma concentration in the MCAO/R rats decreased from 10.67 min to 8.83 min, the area under the concentration-time curve decreased significantly, and the half-life increased from 31.81 min to 78.85 min.

CONCLUSIONS

The rapid absorption and low absolute bioavailability of 4-HBd by gavage in rats are followed by rapid and wide distribution to various tissues and organs, including the brain. The prototype drug is excreted in the feces and urine in low amounts, and it is metabolized to 4-HBA in large amounts in vivo; the pathological state of the MCAO/R model mainly affects its absorption degree and metabolism rate.

Hyperbaric oxygen improves cerebral ischemia-reperfusion injury in rats via inhibition of ferroptosis

BACKGROUND

Our previous study found that hyperbaric oxygen (HBO) attenuated cognitive impairment in mice induced by cerebral ischemia-reperfusion injury (CIRI). However, its mechanism of action is not fully understood. In this study, we aimed to establish a rat model of cerebral ischemia-reperfusion, explore the possible role of ferroptosis in the pathogenesis of CIRI, and observe the effect of HBO on ferroptosis-mediated CIRI.

METHODS

Sprague Dawley (SD) rats were randomly divided into control, model, Ferrostatin-1 (Fer-1), HBO and Fer-1+ HBO groups. Morris water maze, myelin basic protein (MBP) and β-tubulin immunoreactivity were assessed to evaluate the neuroprotective effects of HBO on cerebral ischemia reperfusion injury. Ferroptosis were examined to investigate the mechanism underlying the effects of HBO.

RESULTS

Our result showed that Fer-1 and HBO improved learning and memory ability in the navigation trail and probe trail of the Morris water maze and increased MBP and β-tubulin immunoreactivity of the cortex in the model rats. The levels of ferritin, malondialdehyde (MDA) and glutathione (GSH) in the serum were also reversed by Fer-1 and HBO treatment. Mitochondrial cristae dissolution and vacuolization were observed in the model group by transmission electron microscopy and these conditions were improved in the Fer-1 and HBO groups. Furthermore, Fer-1 and HBO treatment reversed Prostaglandin-Endoperoxide Synthase 2 (PTGS2), Iron Responsive Element Binding Protein 2 (IREB2), acyl-CoA synthetase long chain family member 4 (ACSL4) and Solute Carrier Family 7 Member 11 (SLC7A11) mRNA levels and Transferrin Receptor 1 (TFR1), ferritin light chain (FTL), ferritin heavy chain 1 (FTH1), glutathione peroxidase 4 (GPX4), Nuclear factor E2-related factor 2 (Nrf2), lysophosphatidylcholine acyltransferase 3 (LPCAT3), c-Jun N-terminal kinase (JNK), phosphorylated c-Jun N-terminal kinase (P-JNK) phosphorylated Extracellular signal-regulated protein kinase (P-ERK) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK) protein levels. The above changes were more pronounced in Fer-1+ HBOGroup.

DISCUSSION

The results of the present study indicated that HBO improves cerebral ischemia-reperfusion injury in rats, which may be related to inhibition of ferroptosis. This also means that ferroptosis may become a new target of HBO against CIRI.

De Novo Biosynthesis of Anisyl Alcohol and Anisyl Acetate in Engineered Escherichia coli

Anisyl alcohol and its ester anisyl acetate are both important fragrance compounds and have a wide range of applications in the cosmetics, perfumery, and food industries. The currently commercially available anisyl alcohol and anisyl acetate are based on chemical synthesis. However, consumers increasingly prefer natural fragrance compounds. Therefore, it is of great significance to construct microbial cell factories to produce anisyl alcohol and anisyl acetate. In this study, we first established a biosynthetic pathway in engineered Escherichia coli MG1655 for the production of anisyl alcohol from simple carbon sources. We further increased the anisyl alcohol production to 355 mg/L by the increasing availability of erythrose-4-phosphate and phosphoenolpyruvate. Finally, we further demonstrated the production of anisyl acetate by overexpressing alcohol acetyltransferase ATF1 for the subsequent acetylation of anisyl alcohol to produce anisyl acetate. To our knowledge, this is the first report on the biosynthesis of anisyl alcohol and anisyl acetate directly from a renewable carbon source.

Protective multi‑target effects of DL‑3‑n‑butylphthalide combined with 3‑methyl‑1‑phenyl‑2‑pyrazolin‑5‑one in mice with ischemic stroke

DL-3-n-butylphthalide (NBP) and 3-methyl-1- phenyl-2-pyrazolin-5-one (edaravone) are acknowledged neuroprotective agents that protect against ischemic stroke. However, the underlying mechanisms of a combination therapy with NBP and edaravone have not yet been fully clarified. The aim of the present study was to explore whether the co-administration of NBP and edaravone had multi-target protective effects on the neurovascular unit (NVU) of mice affected by ischemic stroke. Male C57BL/6 mice were randomly divided into the following three groups: i) Sham operation control, ii) middle cerebral artery occlusion (MCAO) and reperfusion, iii) and MCAO/reperfusion with the co-administration of NBP (40 mg/kg) and edaravone (6 mg/kg) delivered via intraperitoneal injection at 0 and 4 h after reperfusion (NBP + edaravone). After ischemia and reperfusion, infarct volumes and neurological deficits were evaluated. The immunoreactivity of the NVU, comprising neurons, endothelial cells and astrocytes, was determined using immunofluorescence staining of neuronal nuclei (NeuN), platelet and endothelial cell adhesion molecule 1 (CD31) and glial fibrillary acidic protein (GFAP). Western blotting was used to detect the expression levels of apoptosis-related proteins. The infarct volume, neurological function scores and cell damage were increased in the MCAO group compared with the sham operation group. Furthermore, the MCAO mice had reduced NeuN and CD31 expression and increased GFAP expression compared with the sham group. By contrast, the NBP + edaravone group exhibited reduced cell damage and consequently lower infarct volume and neurological deficit scores compared with the MCAO group. The NBP + edaravone group exhibited increased NeuN and CD31 expression and decreased GFAP expression compared with the MCAO group. Furthermore, the expression levels of Bax and cleaved caspase-3 in the NBP + edaravone group were decreased significantly compared with the MCAO group, while the expression levels of Bcl-2 and mitochondrial cytochrome c were increased. In conclusion, the results of the present study demonstrated that NBP and edaravone effectively prevented ischemic stroke damage with multi-target protective effects. In addition, NBP + edaravone may be a promising combination therapy for ischemic stroke.

CHRFAM7A Overexpression Attenuates Cerebral Ischemia-Reperfusion Injury via Inhibiting Microglia Pyroptosis Mediated by the NLRP3/Caspase-1 pathway

Cerebral ischemia-reperfusion (I/R) injury is an inflammation-related disease. CHRFAM7A can regulate inflammatory responses. Therefore, the present study investigated the mechanism of CHRFAM7A in cerebral I/R injury. CHRFAM7A expression and inflammatory cytokine levels in patients with cerebral I/R injury and oxygen-glucose deprivation/reperfusion (OGD/R)-treated microglia were detected. The proliferation, inflammatory cytokine expressions, nod-like receptor protein 3 (NLRP3) level, cell pyroptosis, and viability and lactate dehydrogenase (LDH) activity in OGD/R-treated microglia were detected after CHRFAM7A overexpression. The NLRP3/Caspase-1 pathway was activated to assess the effect of CHRFAM7A on microglia. Expressions of microglial M1 phenotype marker iNOS and M2 marker Arg1 were detected. Downregulated CHRFAM7A and elevated inflammatory cytokine levels were observed in patients with cerebral I/R injury and OGD/R-treated microglia. In OGD/R-treated microglia, CHRFAM7A overexpression promoted cell proliferation and viability, reduced inflammation and LDH activity, and inhibited NLRP3 inflammasome activation and cell pyroptosis. Mechanically, CHRFAM7A inhibited microglia pyroptosis via inhibiting the NLRP3/Caspase-1 pathway and reduced cell inflammatory injury via promoting microglia polarization from M1 to M2. Overall, CHRFAM7A overexpression attenuated cerebral I/R injury by inhibiting microglia pyroptosis in a NLRP3/Caspase-1 pathway-dependent manner and promoting microglia polarization to M2 phenotype.

Alteration of N 6 -Methyladenosine mRNA Methylation in a Rat Model of Cerebral Ischemia-Reperfusion Injury

Aim

This study was conducted in order to reveal the alterations in the N⁶-methyladenosine (m6A) modification profile of cerebral ischemia–reperfusion injury model rats.

Materials and Methods

Rats were used to establish the middle cerebral artery occlusion and reperfusion (MCAO/R) model. MeRIP-seq and RNA-seq were performed to identify differences in m6A methylation and gene expression. The expression of m6A methylation regulators was analyzed in three datasets and detected by quantitative real-time polymerase chain reaction, western blot, and immunofluorescence.

Results

We identified 1,160 differentially expressed genes with hypermethylated or hypomethylated m6A modifications. The differentially expressed genes with hypermethylated m6A modifications were involved in the pathways associated with inflammation, while hypomethylated differentially expressed genes were related to neurons and nerve synapses. Among the m6A regulators, FTO was specifically localized in neurons and significantly downregulated after MCAO/R.

Conclusion

Our study provided an m6A transcriptome-wide map of the MACO/R rat samples, which might provide new insights into the mechanisms of cerebral ischemia–reperfusion injury.

Carthamin yellow improves cerebral ischemia‑reperfusion injury by attenuating inflammation and ferroptosis in rats

Carthamin yellow (CY), a flavonoid compound extracted from safflower, has been reported to attenuate cardiac ischemia and reperfusion injury. However, whether CY could ameliorate ischemic stroke is not completely understood. In the present study, the preventive effects of CY on experimental ischemic stroke were investigated using middle cerebral artery occlusion (MCAO) model rats. Neurological scores, brain edema, infarct area and microtubule‑associated protein 2 (MAP‑2) immunoreactivity were assessed to evaluate the effects of CY on ischemic brain injury. The involvement of inflammation and ferroptosis were examined to investigate the mechanism underlying the effects of CY. The results demonstrated that 2‑week CY treatment attenuated the neurological deficit score, brain water content and infarct area, and increased MAP‑2 immunoreactivity in the cortex in MCAO model rats. CY administration also deactivated the cortex NF‑κB/NLR family pyrin domain containing 3 inflammasome signaling pathway, and decreased serum TNF‑α, IL‑1β and IL‑6 concentrations. Moreover, CY treatment inhibited Fe²⁺ and reactive oxygen species accumulation, and reversed acyl‑CoA synthetase long‑chain family member 4, transferrin receptor 1, glutathione peroxidase 4 and ferritin heavy chain 1 protein expression levels in the brain. The levels of glutathione, superoxide dismutase and malondialdehyde in the serum were also reversed by CY treatment. Collectively, the results of the present study demonstrated that CY protected rats against ischemic stroke, which was associated with mitigation of inflammation and ferroptosis.

Knockdown of long non-coding RNA RMRP protects cerebral ischemia-reperfusion injury via the microRNA-613/ATG3 axis and the JAK2/STAT3 pathway

Cerebral ischemia-reperfusion (I/R) injury can induce the mitophagy of neurons in the ischemic brain. Long non-coding RNAs (lncRNAs) play an important role in the pathogenesis of various injuries, especially in cerebral I/R injury. The purpose of this study is to investigate the molecular mechanism of lncRNA RNA component of mitochondrial RNA processing endoribonuclease (RMRP) in cerebral I/R injury. The middle cerebral artery occlusion (MCAO) mouse model was established. Neurological deficit score, pathological structure, infarcted area, neuron number, cell apoptosis, and coagulation ability of MCAO mice were evaluated. The expressions of RMRP, microRNA (miR)-613, and ATG3 in MCAO mice were detected. The binding relationships among miR-613, RMRP, and ATG3 were predicted and verified. Neuro 2A (N2a) cells were treated with oxygen-glucose deprivation/reperfusion (OGD/R) to simulate I/R injury. Cell viability and apoptosis assays were performed. The effects of miR-613, ATG3, and RMRP on I/R injury were verified by functional rescue experiments. JAK2/STAT3 phosphorylation level was detected. We found significantly upregulated RMRP and ATG3, and downregulated miR-613 expressions in MCAO mice. RMRP could escalate ATG3 mRNA expression through miR-613. RMRP knockdown promoted viability and inhibited apoptosis of OGD/R-treated N2a cells, which could be reversed by miR-613 inhibition or ATG3 overexpression. RMRP overexpression inhibited the activation of JAK2/STAT3 signaling pathway. We demonstrated that lncRNA RMRP competitively bound to miR-613, leading to the increase of ATG3 expression and the inhibition the JAK2/STAT3 pathway, thus promoting cerebral I/R injury in mice.

Neurovascular Unit: A critical role in ischemic stroke

Ischemic stroke (IS), a common cerebrovascular disease, results from a sudden blockage of a blood vessel in the brain, thereby restricting blood supply to the area in question, and making a significantly negative impact on human health. Unfortunately, current treatments, that are mainly based on a recanalization of occluded blood vessels, are insufficient or inaccessible to many stroke patients. Recently, the profound influence of the neurovascular unit (NVU) on recanalization and the prognosis of IS have become better understood; in‐depth studies of the NVU have also provided novel approaches for IS treatment. In this article, we review the intimate connections between the changes in the NVU and IS outcomes, and discuss possible new management strategies having practical significance to IS. We discuss the concept of the NVU, as well as its roles in IS blood‐brain barrier regulation, cell preservation, inflammatory immune response, and neurovascular repair. Besides, we also summarize the influence of noncoding RNAs in NVU, and IS therapies targeting the NVU. We conclude that both the pathophysiological and neurovascular repair processes of IS are strongly associated with the homeostatic state of the NVU and that further research into therapies directed at the NVU could expand the range of treatments available for IS.

Isoflurane post-conditioning attenuates cerebral ischemia/reperfusion injury by reducing apoptotic through activating the BMP7/SMAD signaling pathway in rats

The expressions of different temporal patterns of bone morphogenetic proteins (BMPs) have changed after ischemic strokes, and ischemic preconditioning-induced neuroprotection was attenuated when BMP7 was inhibited. In the previous study, the neuroprotection of isoflurane postconditioning (ISPOC) against cerebral ischemia-reperfusion (I/R) injury has been addressed, with particular relevance to the role of BMP7. Consequently, in the present study, we continued to explore the mechanisms involved in the BMP7 signal mediated the neuroprotection of ISPOC. A rat model of the middle cerebral artery occlusion was used in this study. Rats were administered 1.5 % isoflurane, 60 min after 90 min of ischemia, followed by a 24 h reperfusion period. The 1.5 % ISPOC significantly ameliorated the cerebral infarct volumes, neurologic deficit scores, damaged neurons, and apoptotic neurons. Moreover, ISPOC unregulated the expressions of BMP7, p-Smad1/5/9, and p-p38. Whereas, the neuroprotective effect was weakened by LDN-193189 and SB203580, respectively, a BMP7/Smad1/5/9 and p38MAPK signaling pathway inhibitor. Furthermore, LDN-193189 downregulated the expression of p-p38. The present results of this study indicated that the neuroprotection of 1.5 % isoflurane postconditioning to cerebral ischemia-reperfusion injury is related to the activating of BMP7/Smad1/5/9 and p38MAPK signal pathway.