Propofol-induced neurotoxicity in hESCs involved in activation of miR-206/PUMA signal pathway

Propofol-Induced Developmental Neurotoxicity: From Mechanisms to Therapeutic Strategies

Propofol is the most commonly used intravenous general anesthetic in clinical anesthesia, and it is also widely used in general anesthesia for pregnant women and infants. Some clinical and preclinical studies have found that propofol causes damage to the immature nervous system, which may lead to neurodevelopmental disorders and cognitive dysfunction in infants and children. However, its potential molecular mechanism has not been fully elucidated. Recent in vivo and in vitro studies have found that some exogenous drugs and interventions can effectively alleviate propofol-induced neurotoxicity. In this review, we focus on the relevant preclinical studies and summarize the latest findings on the potential mechanisms and therapeutic strategies of propofol-induced developmental neurotoxicity.

Recent progress on the role of non-coding RNA in postoperative cognitive dysfunction

Postoperative cognitive dysfunction (POCD), especially in elderly patients, is a serious complication characterized by impairment of cognitive and sensory modalities after surgery. The pathogenesis of POCD mainly includes neuroinflammation, neuronal apoptosis, oxidative stress, accumulation of Aβ, and tau hyperphosphorylation; however, the exact mechanism remains unclear. Non-coding RNA (ncRNA) may play an important role in POCD. Some evidence suggests that microRNA, long ncRNA, and circular RNA can regulate POCD-related processes, making them promising biomarkers in POCD diagnosis, treatment, and prognosis. This article reviews the crosstalk between ncRNAs and POCD, and systematically discusses the role of ncRNAs in the pathogenesis and diagnosis of POCD. Additionally, we explored the possible mechanisms of ncRNA-associated POCD, providing new knowledge for developing ncRNA-based treatments for POCD.

MicroRNA-424-5p Alleviates Isoflurane Anesthesia-Induced Neurotoxicity in Human Embryonic Stem Cell-Derived Neurons by Targeting FASN

Isoflurane (ISO) is a type of anesthetic that might cause neurotoxicity in children. Although miR-424-5p is considerably downregulated in ISO-treated rat brain samples, its physiological role in ISO-induced neuronal injury in human embryonic stem cell-derived neurons remains unknown (hESC-derived neurons). miR-424-5p expression and fatty acid synthase (FASN) in ISO-treated hESC-derived neurons were tested via qRT-PCR. The amount of protein for Bax, Cleaved-caspase-8, Bcl-2, and FASN was investigated through western blot analysis. The viability and apoptosis of hESC-derived neurons were estimated through cell counting kit-8 assessment and TUNEL assay, accordingly. Superoxide dismutase, glutathione, and malondialdehyde levels were discovered via corresponding kits. The contents of inflammatory factors including interleukin-6 and tumor necrosis factor-α were examined by enzyme-linked immunosorbent assays. The combination between FASN and miR-424-5p was resolute via dual-luciferase reporter assessment. After exposure to ISO, induced neurotoxicity and a decreased miR-424-5p production were identified in hESC-derived neurons. Upregulation of miR-424-5p repressed ISO-induced apoptosis and mitigated ISO-induced inflammatory response and oxidative stress in vitro. FASN expression levels were reduced by elevation of miR-424-5p and upregulated after ISO treatment. Mechanically, FASN was directly targeted by miR-424-5p in hESC-derived neurons. Of note, the miR-424-5p elevation-suppressed neuronal apoptosis, inflammatory response, and oxidative stress were countered by upregulation of FASN.

Propofol induces the apoptosis of neural stem cells via microRNA-9-5p / chemokine CXC receptor 4 signaling pathway

Recent studies suggested that propofol, one of the most widely used anesthetics, may cause neurotoxicity in the developing brain, leading to cognitive deficits in adults. However, the underlying mechanisms remain unclear. In this study, we aimed to evaluate the mechanisms of propofol neurotoxicity in the neural stem cells (NSCs). The mRNA and protein expression levels of microRNA-9-5p (miR-9-5p) and chemokine CXC receptor 4 (CXCR4) were determined by quantitative reverse transcription-polymerase chain reaction and Western blotting analyses. Cell viability and apoptosis were evaluated using the cell counting kit-8 and Hoechst staining kits. The levels of apoptosis-related proteins B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein, and caspase-3 were detected by Western blotting analysis. These results confirmed that propofol activated cell apoptosis in a dose-dependent manner. A significant increase in the miR-9-5p and CXCR4 expression was observed in the propofol-treated cells. The overexpression of miR-9-5p induced apoptosis in NSCs, accompanied by elevated apoptosis-related protein activity. Furthermore, mitigated CXCR4 expression reduced propofol-induced cell apoptosis. We conclude that propofol induces cell death in NSCs, and overexpression of miR-9-5p/CXCR4 contributes to propofol-induced cell apoptosis, which might be a target for developing novel strategies to treat propofol neurotoxicity.

The importance of non-coding RNAs in environmental stress-related developmental brain disorders: A systematic review of evidence associated with exposure to alcohol, anesthetic drugs, nicotine, and viral infections

Brain development is a dynamic and lengthy process that includes cell proliferation, migration, neurogenesis, gliogenesis, synaptogenesis, and pruning. Disruption of any of these developmental events can result in long-term outcomes ranging from brain structural changes, to cognitive and behavioral abnormality, with the mechanisms largely unknown. Emerging evidence suggests non-coding RNAs (ncRNAs) as pivotal molecules that participate in normal brain development and neurodevelopmental disorders. NcRNAs such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are transcribed from the genome but not translated into proteins. Many ncRNAs have been implicated as tuners of cell fate. In this review, we started with an introduction of the current knowledge of lncRNAs and miRNAs, and their potential roles in brain development in health and disorders. We then reviewed and discussed the evidence of ncRNA involvement in abnormal brain development resulted from alcohol, anesthetic drugs, nicotine, and viral infections. The complex connections among these ncRNAs were also discussed, along with potential overlapping ncRNA mechanisms, possible pharmacological targets for therapeutic/neuroprotective interventions, and potential biomarkers for brain developmental disorders.

Edaravone Alleviated Propofol-Induced Neurotoxicity in Developing Hippocampus by mBDNF/TrkB/PI3K Pathway

Background

To investigate the neuroprotective effect of edaravone on excessive-dose propofol-induced neurotoxicity in the hippocampus of newborn rats and HT22 cells.

Methods

Cell proliferation was investigated by assessing ki67 expression in the neural stem of the hippocampus of newborn rats and by cell counting kit-8 (CCK8) assay in HT22 cells. Cell apoptosis was assessed in vivo by caspase 3 detection in Western blots and measurement of apoptosis in neurons and glial cells by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Apoptosis was analyzed by flow cytometry in HT22 cells. The Morris water maze was used to evaluate the long-term learning and memory ability of rats. Inflammatory factors were detected by enzyme-linked immunosorbent assay (ELISA). The expression of mBDNF/TrkB/PI3K pathway-related proteins was detected by Western blot and quantitative reverse transcription-polymerase chain reaction (q-RT PCR).

Results

In neonatal rat hippocampus and HT22 cells, edaravone increased cell proliferation and decreased cell apoptosis after excessive propofol-induced neurotoxicity. In addition, the levels of proinflammatory factors interleukin (IL)-6 and tumor necrosis factor (TNF)-α were reduced by edaravone pretreatment. The use of the tropomyosin receptor kinase B (TrkB) antagonist ANA-12 and TrkB agonist 7,8DHF with propofol groups showed that edaravone mitigated excessive propofol-induced neurotoxicity through the mature brain-derived neurotrophic factor (mBDNF)/TrkB/phosphoinositide 3-kinase (PI3K) pathway. However, the current dose of propofol did not significantly affect long-term learning and memory in rats.

Conclusion

Edaravone pretreatment ameliorated propofol-induced proliferation inhibition, neuroapoptosis, and neural inflammation by activating the mBDNF/TrkB/PI3K pathway.

Upregulation of miR-496 Rescues Propofol-induced Neurotoxicity by Targeting Rho Associated Coiled-coil Containing Protein Kinase 2 (ROCK2) in Prefrontal Cortical Neurons

OBJECTIVE

Early exposure to general anesthesia in children might be a potentially highrisk factor for learning and behavioral disorders. The mechanism of neurotoxicity induced by general anesthesia was not defined. miR-496 could regulate cerebral injury, while the roles of miR- 496 in neurotoxicity were not elucidated. Therefore, we aimed to investigate the effects of miR- 496 in neurotoxicity induced by propofol.

METHODS

Primary Prefrontal Cortical (PFC) neurons were isolated from neonatal rats and treated with propofol to induce neurotoxicity. Cell viability was detected by (3-(4,5-Dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and cell apoptosis was assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The target relationship of miR-496 and Rho Associated Coiled-Coil Containing Protein Kinase 2 (ROCK2) was explored using luciferase assays.

RESULTS

Propofol decreased cell viability, promoted cell apoptosis, and decreased the expression of miR-496 in PFC neurons in a dose-dependent manner. Overexpression of miR-496 attenuated neurotoxicity induced by propofol in PFC neurons. ROCK2 was a target of miR-496, and miR-496 oppositely modulated the expression of ROCK2. Besides, propofol increased the expression of ROCK2 through inhibiting miR-496 in PFC neurons. Overexpression of miR-496 attenuated propofol- induced neurotoxicity by targeting ROCK2 in PFC neurons.

CONCLUSION

miR-496 was decreased in PFC neurons treated with propofol, and overexpression of miR-496 attenuated propofol-induced neurotoxicity by targeting ROCK2. miR-496 and ROCK2 may be promising targets for protecting propofol-induced neurotoxicity.

MicroRNA-665 mediates propofol-induced cell apoptosis in human stem cell-derived neurons

We aimed to evaluate the neurotoxicity and mechanisms of anesthetics propofol in hESC-derived neurons. Cell apoptosis in hESC-derived neurons' exposure to 4, 10 and 20 μg/mL propofol for 6 h was assessed using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate in situ nick end labeling (TUNEL) staining and microRNA-665 (miR-665) expression was assessed using quantitative reverse transcription polymerase chain reaction (qRT-PCR). miR-665 was overexpressed and knocked down using a miR-665 mimic and anti-665 transfection, respectively. The results showed that hESCs exposed to propofol showed a dose-dependent cell apoptosis, followed by the upregulation of miR-665 expression. Overexpression of miR-665 increased propofol-induced apoptosis in hESC cells. And targeting miR-665 decreased propofol-induced cell apoptosis in hESC cells. These data suggest that propofol induces cell death in hESC-derived neurons and the propofol-induced cell apoptosis may occur via miR-665-dependent mechanism.

MicroRNA-582-5p Reduces Propofol-induced Apoptosis in Developing Neurons by Targeting ROCK1

BACKGROUND

Propofol is an intravenous drug commonly used in anesthesia procedures and intensive care in children. However, it also has neurotoxic effects on children. MicroRNA plays an important role in neurological diseases and neurotoxicity.

METHODS

In this study, primary rat hippocampal neurons were used to investigate the role of miR- 582-5p in propofol-induced neurotoxicity. Cell viability was monitored by 3-(4,5-dimethylthiazolyl)- 2,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, while the expression of proteins was monitored by real-time quantitation polymerase chain reaction (RT-qPCR) and western blot. TargetScan and double luciferase report assay were used to predict the targeting relationship between miR-582-5p and Rho-associated serine-threonine protein kinase 1 (ROCK1).

RESULTS

In the present study, the viability of neurons and the expression of miR-582-5p were decreased in a time-dependent manner after propofol treatment. Besides, miR-582-5p overexpression significantly reduced the toxicity of propofol on neuron cells but had no significant effect on normal nerve cells. In addition, miR-582-5p overexpression significantly reversed the expression of apoptosis-related proteins (cleaved caspase 3 and cleaved caspase 9) induced by propofol but had no significant effect in normal nerve cells. TargetScan and Dual-luciferase report assay revealed that ROCK1 was a targeted regulatory gene for miR-582-5p, and propofol treatment up-regulated ROCK1 expression by inhibiting miR-582-5p expression. Notably, miR-582-5p overexpression significantly increased cell viability, while ROCK1 overexpression reversed the effect of miR-582- 5p.

CONCLUSION

Taken together, these findings suggest that miR-582-5p alleviated propofol-induced apoptosis of newborn rat neurons by inhibiting ROCK1.

Propofol Inhibits the Migration and Invasion of Glioma Cells by Blocking the PI3K/AKT Pathway Through miR-206/ROCK1 Axis

Background

Propofol has been identified to perform anti-tumor functions in glioma. However, the molecular mechanisms underlying propofol-induced prevention on migration and invasion of glioma cells remain unclear.

Methods

Cell proliferation, invasion and migration were measured by 3-(4,5)-dimethylthiahiazo(−z-y1)-3,5-di-phenytetrazoliumromide assay and transwell assay, respectively. The expression of microRNA (miR)-206 and Rho-associated coiled coil-containing protein kinase 1 (ROCK1) was detected by quantitative real-time polymerase chain reaction. Western blot was used to measure the activation of the PI3K/AKT pathway. The interaction between miR-206 and ROCK1 was analyzed using the dual-luciferase reporter assay, RNA immunoprecipitation assay, and pull-down assay.

Results

Propofol treatment inhibited the migration, invasion, and PI3K/AKT pathway activation in glioma cells. MiR-206 was decreased in glioma tissues and cells, while propofol exposure induced the upregulation of miR-206 in glioma cells. Besides that, we also found overexpressed miR-206 enhanced propofol-mediated inhibition on the migration, invasion, and PI3K/AKT pathway activation of glioma cells. Subsequently, ROCK1 was confirmed to be a target of miR-206. ROCK1 was elevated in glioma tissues and cells, but was reduced by propofol exposure in glioma cells. The rescue assay indicated that the miR-206/ROCK1 axis was involved in propofol-induced inhibition on the migration, invasion, and PI3K/AKT pathway activation in glioma cells.

Conclusion

Propofol inhibited the migration and invasion of glioma cells by blocking the PI3K/AKT pathway through the miR-206/ROCK1 axis, suggesting an effective clinical implication for the anesthetic to prevent the metastasis of glioma.

Role of MicroRNAs in Anesthesia-Induced Neurotoxicity in Animal Models and Neuronal Cultures: a Systematic Review

Exposure to anesthetic agents in early childhood or late intrauterine life might be associated with neurotoxicity and long-term neurocognitive decline in adulthood. This could be attributed to induction of neuroapoptosis and inhibition of neurogenesis by several mechanisms, with a pivotal role of microRNAs in this milieu. MicroRNAs are critical regulators of gene expression that are differentially expressed in response to internal and external environmental stimuli, including general anesthetics. Through this systematic review, we aimed at summarizing the current knowledge apropos of the roles and implications of deregulated microRNAs pertaining to anesthesia-induced neurotoxicity in animal models and derived neuronal cultures. OVID/Medline and PubMed databases were lastly searched on April 1st, 2019, using the Medical Subject Heading (MeSH) or Title/Abstract words ("microRNA" and "anesthesia"), to identify all published research studies on microRNAs and anesthesia. During the review process, data abstraction and methodological assessment was done by independent groups of reviewers. In total, 29 studies were recognized to be eligible and were thus involved in this systematic review. Anesthetic agents studied included sevoflurane, isoflurane, propofol, bupivacaine, and ketamine. More than 40 microRNAs were identified to have regulatory roles in anesthesia-induced neurotoxicity. This field of study still comprises several gaps that should be filled by conducting basic, clinical, and translational research in the future to decipher the exact role of microRNAs and their functions in the context of anesthesia-induced neurotoxicity.

[Exposure to propofol down-regulates myelin basic protein expression in zebrafish embryos: its neurotoxicity on oligodendrocytes and the molecular mechanisms]

OBJECTIVE

To investigate the mechanism underlying propofol- induced down-regulation of myelin basic protein (MBP) in zebrafish embryos.

METHODS

Zebrafish embryos (6-48 h post-fertilization [hpf]) were randomized into 4 equal groups for exposure to dimethyl sulfoxide (DMSO), 20 μg/mL propofol, 30 μg/mL propofol, or no particular treatment (control group). The larvae were collected at 48 or 72 hpf for detecting the mRNA levels of MBP, Olig1, Olig2, and Sox10 using qRT-PCR (n=80). The protein expression of MBP was quantitatively detected using Western blotting (n=80), and the apoptosis of the oligodendrocytes was investigated using TUNEL staining (n=6).

RESULTS

Exposure to 20 and 30 μg/mL propofol caused significant reductions in the mRNA expressions of Olig1, Olig2, and Sox10 at 48 and 72 hpf (P < 0.05) and also in MBP mRNA and protein levels at 72 hpf (P < 0.05). Exposure to 30 μg/mL propofol induced more obvious reduction in MBP protein expression than 20 μg/mL propofol at 72 hpf (P < 0.05), and the exposures resulted in a significant increase of oligodendrocyte apoptosis at 72 hpf (P < 0.05).

CONCLUSIONS

Propofol exposure reduces MBP expression at both the mRNA and protein levels in zebrafish embryos by down-regulating the expressions of Olig1, Olig2 and Sox10 mRNA levels and increasing apoptosis of the oligodendrocytes.