Nrf2 mediates the neuroprotective effect of isoflurane preconditioning in cortical neuron injury induced by oxygen-glucose deprivation

Isoflurane preconditioning attenuates OGD/R-induced cardiomyocyte cytotoxicity by regulating the miR-210/BNIP3 axis

Isoflurane, a commonly used inhaled anesthetic, has been found to have a cardioprotective effect. However, the precise mechanisms have not been fully elucidated. Here, we found that isoflurane preconditioning enhanced OGD/R-induced upregulation of miR-210, a hypoxia-responsive miRNA, in AC16 human myocardial cells. To further test the roles of miR-210 in regulating the effects of isoflurane preconditioning on OGD/R-induced cardiomyocyte injury, AC16 cells were transfected with anti-miR-210 or control anti-miRNA. Results showed that isoflurane preconditioning attenuated OGD/R-induced cardiomyocyte cytotoxicity (as assessed by cell viability, LDH and CK-MB levels), which could be reversed by anti-miR-210. Isoflurane preconditioning also prevented OGD/R-induced increase in apoptotic rate, caspase-3 and caspase-9 activities, and Bax level and decrease in Bcl-2 expression level, while anti-miR-210 blocked these effects. We also found that anti-miR-210 prevented the inhibitory effects of isoflurane preconditioning on OGD/R-induced decrease in adenosine triphosphate content; mitochondrial volume; citrate synthase activity; complex I, II, and IV activities; and p-DRP1 and MFN2 expression. Besides, the expression of BNIP3, a reported direct target of miR-210, was significantly decreased under hypoxia condition and could be regulated by isoflurane preconditioning. In addition, BNIP3 knockdown attenuated the effects of miR-210 silencing on the cytoprotection of isoflurane preconditioning. These findings suggested that isoflurane preconditioning exerted protective effects against OGD/R-induced cardiac cytotoxicity by regulating the miR-210/BNIP3 axis.

Linoleic Acid Alleviates Lipopolysaccharide Induced Acute Liver Injury via Activation of Nrf2

Linoleic acid (LA) not only functions as an essential nutrient, but also profoundly modulates oxidative stress and inflammatory response. However, the potential mechanisms have not been adequately researched. Hence, this study examined the potential pharmacological roles of LA and the underlying mechanisms in mice with lipopolysaccharide (LPS)-associated acute liver injury (ALI). The results indicated that treatment with LA alleviated the histopathological abnormalities in the hepatic and plasma levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and glutathione-S-transferase (GST) in mice with LPS exposure. In addition, LA inhibited the LPS-associated generation of proinflammatory factors, such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6), and downregulated the hepatic myeloperoxidase (MPO) level. In addition, the administration of LA resulted in a reduction in hepatic malondialdehyde (MDA) levels and an elevation in liver superoxide dismutase (SOD), reduced glutathione (GSH), catalase (CAT), and glutathione peroxidase (GSH-PX) levels. Further investigations revealed that LA promoted the expression of nuclear factor E2-related factor (Nrf2) and NAD(P)H: quinone oxidoreductase 1 (NQO1). In addition, the beneficial outcomes of LA on LPS-induced acute liver failure were revered when Nrf2 was pharmacologically suppressed by ML385. These experimental results demonstrated that LA supplementation attenuated LPS-associated acute hepatic impairment in mice via the activation of Nrf2.

Research hotspots and frontiers of preconditioning in cerebral ischemia: A bibliometric analysis

Background

Preconditioning is a promising strategy against ischemic brain injury, and numerous studies in vitro and in vivo have demonstrated its neuroprotective effects. However, at present there is no bibliometric analysis of preconditioning in cerebral ischemia. Therefore, a comprehensive overview of the current status, hot spots, and emerging trends in this research field is necessary.

Materials and methods

Studies on preconditioning in cerebral ischemia from January 1999-December 2022 were retrieved from the Web of Science Core Collection (WOSCC) database. CiteSpace was used for data mining and visual analysis.

Results

A total of 1738 papers on preconditioning in cerebral ischemia were included in the study. The annual publications showed an upwards and then downwards trend but currently remain high in terms of annual publications. The US was the leading country, followed by China, the most active country in recent years. Capital Medical University published the largest number of articles. Perez-Pinzon, Miguel A contributed the most publications, while KITAGAWA K was the most cited author. The focus of the study covered three areas: (1) relevant diseases and experimental models, (2) types of preconditioning and stimuli, and (3) mechanisms of ischemic tolerance. Remote ischemic preconditioning, preconditioning of mesenchymal stem cells (MSCs), and inflammation are the frontiers of research in this field.

Conclusion

Our study provides a visual and scientific overview of research on preconditioning in cerebral ischemia, providing valuable information and new directions for researchers.

Inhibiting specificity protein 1 attenuated sevoflurane-induced mitochondrial stress and promoted autophagy in hippocampal neurons through PI3K/Akt/mTOR and α7-nAChR signaling

Sevoflurane, a commonly used anesthetic in surgery, is considered as an inducer of neurodegenerative diseases and postoperative complications including postoperative cognitive dysfunction. Evidence showed that specificity protein 1 (SP1) participated in the regulation of various cellular processes. Also, SP1 was found to modulate sevoflurane-induced hippocampal inflammatory injury both in vitro and in vivo. Our study aimed to illustrate the role of SP1 in mediating mitochondrial stress and autophagy in neurons under sevoflurane exposure. SiRNA for SP1 was transfected in to hippocampus neurons for the loss-of-function assay before sevoflurane stimulation. Meanwhile, recilisib was utilized for PI3K/Akt/mTOR signaling activation, GTS-21 and MLA (methylycaconitine citrate) were used to activate or inactivate alpha 7 nicotinic acetylcholine receptor (α7-nAChR), respectively. Sevoflurane induced SP1 upregulation and autophagy suppression. Interfering SP1 dramatically depressed the promoted oxidative stress and mitochondrial dysfunction induced by sevoflurane. Additionally, SP1 silence blocked sevoflurane-induced activation of PI3K/Akt/mTOR signaling and inhibition of α7-nAChR. Restoring PI3K/Akt/mTOR signaling or depressing CAP significantly reversed the repressive effects of SP1 knockdown on mitochondrial stress and autophagy imbalance in hippocampal cells. In conclusions, our research indicated that SP1 regulated sevoflurane-induced oxidative stress dysregulation, mitochondrial function and cell autophagy in hippocampus via mediating the PI3K/Akt/mTOR and α7-nAChR pathways. Therefore, it might provide a novel sight for sevoflurane-induced hippocampus injury and POCD therapy.