Sevoflurane anesthesia represses neurogenesis of hippocampus neural stem cells via regulating microRNA-183-mediated NR4A2 in newborn rats

SIRT1-driven mechanism: sevoflurane's interference with mESC neural differentiation via PRRX1/DRD2 cascade

Investigating the sevoflurane-induced perturbation in the differentiation of mouse embryonic stem cells (mESCs) into neural stem cells (mNSCs), our study delineates a novel SIRT1/PRRX1/DRD2/PKM2/NRF2 axis as a key player in this intricate process. Sevoflurane treatment hindered mESC differentiation, evidenced by altered expression patterns of pluripotency and neural lineage markers. Mechanistically, sevoflurane downregulated Sirt1, setting in motion a signaling cascade. Sevoflurane may inhibit PKM2 dimerization and NRF2 signaling pathway activation by inhibiting the expression of SIRT1 and its downstream genes Prrx1 and DRD2, ultimately inhibiting mESCs differentiation into mNSCs. These findings contribute to our understanding of the molecular basis of sevoflurane-induced neural toxicity, presenting a potential avenue for therapeutic intervention in sevoflurane-induced perturbation in the differentiation of mESCs into mNSCs by modulating the SIRT1/PRRX1/DRD2/PKM2/NRF2 axis.

Inhalation Anesthetics Play a Janus-Faced Role in Self-Renewal and Differentiation of Stem Cells

Inhalation anesthesia stands as a pivotal modality within clinical anesthesia practices. Beyond its primary anesthetic effects, inhaled anesthetics have non-anesthetic effects, exerting bidirectional influences on the physiological state of the body and disease progression. These effects encompass impaired cognitive function, inhibition of embryonic development, influence on tumor progression, and so forth. For many years, inhaled anesthetics were viewed as inhibitors of stem cell fate regulation. However, there is now a growing appreciation that inhaled anesthetics promote stem cell biological functions and thus are now regarded as a double-edged sword affecting stem cell fate. In this review, the effects of inhaled anesthetics on self-renewal and differentiation of neural stem cells (NSCs), embryonic stem cells (ESCs), and cancer stem cells (CSCs) were summarized. The mechanisms of inhaled anesthetics involving cell cycle, metabolism, stemness, and niche of stem cells were also discussed. A comprehensive understanding of these effects will enhance our comprehension of how inhaled anesthetics impact the human body, thus promising breakthroughs in the development of novel strategies for innovative stem cell therapy approaches.

A Scoping Review of the Mechanisms Underlying Developmental Anesthetic Neurotoxicity

Although anesthesia makes painful or uncomfortable diagnostic and interventional health care procedures tolerable, it may also disrupt key cellular processes in neurons and glia, harm the developing brain, and thereby impair cognition and behavior in children. Many years of studies using in vitro, animal behavioral, retrospective database studies in humans, and several prospective clinical trials in humans have been invaluable in discerning the potential toxicity of anesthetics. The objective of this scoping review was to synthetize the evidence from preclinical studies for various mechanisms of toxicity across diverse experimental designs and relate their findings to those of recent clinical trials in real-world settings.

Brain DNA damaging effects of volatile anesthetics and 1 and 2 Gy gamma irradiation in vivo: Preliminary results

Although both can cause DNA damage, the combined impact of volatile anesthetics halothane/sevoflurane/isoflurane and radiotherapeutic exposure on sensitive brain cells in vivo has not been previously analyzed. Healthy Swiss albino male mice (240 in total, 48 groups) were exposed to either halothane/sevoflurane/isoflurane therapeutic doses alone (2 h); 1 or 2 gray of gamma radiation alone; or combined exposure. Frontal lobe brain samples from five animals were taken immediately and 2, 6, and 24 h after exposure. DNA damage and cellular repair index were analyzed using the alkaline comet assay and the tail intensity parameter. Elevated tail intensity levels for sevoflurane/halothane were the highest at 6 h and returned to baseline within 24 h for sevoflurane, but not for halothane, while isoflurane treatment caused lower tail intensity than control values. Combined exposure demonstrated a slightly halothane/sevoflurane protective and isoflurane protective effect, which was stronger for 2 than for 1 gray. Cellular repair indices and tail intensity histograms indicated different modes of action in DNA damage creation. Isoflurane/sevoflurane/halothane preconditioning demonstrated protective effects in sensitive brain cells in vivo. Owing to the constant increases in the combined use of radiotherapy and volatile anesthetics, further studies should explore the mechanisms behind these effects, including longer and multiple exposure treatments and in vivo brain tumor models.

Tripartite motif 72 inhibits apoptosis and mitochondrial dysfunction in neural stem cells induced by anesthetic sevoflurane by activating PI3K/AKT pathway

Anesthetics exposure induces neurocognitive deficits during brain development and impairs self-renewal and differentiation of neural stem cells (NSCs). Tripartite motif 72 (TRIM72, also known as mitsugumin 53, MG53) is involved in tissue repair and plasma membrane damage repair. The neuroprotective effect of TRIM72 against sevoflurane-induced neurotoxicity of NSCs was investigated in this study. First, human NSCs were exposed to different concentrations of sevoflurane. Results showed that TRIM72 was downregulated in sevoflurane-treated NSCs. Exposure to sevoflurane reduced cell viability in NSCs. Second, sevoflurane-treated NSCs were stimulated with recombinant human TRIM72 (rhTRIM72). Treatment with rhTRIM72 enhanced the cell viability in sevoflurane-treated NSCs. Moreover, treatment with a rhTRIM72-attenuated sevoflurane-induced increase in caspase-3 activity in NSCs. Third, JC-1 aggregates were deceased and JC-1 monomer was increased in sevoflurane-treated NSCs, which were reversed by rhTRIM72. Furthermore, rhTRIM72 also weakened sevoflurane-induced decrease in superoxide dismutase and glutathione peroxidase and increase in malondialdehyde and reactive oxygen species in NSCs. Finally, reduced phosphorylation levels of protein kinase B (AKT) and phosphatidylinositol 3-kinase (PI3K) in sevoflurane-treated NSCs were upregulated by rhTRIM72. In conclusion, TRIM72 inhibited cell apoptosis and reduced the mitochondria membrane potential of sevoflurane-treated NSCs through activation of the PI3K/AKT pathway.

Research progress on molecular mechanisms of general anesthetic-induced neurotoxicity and cognitive impairment in the developing brain

General anesthetics-induced neurotoxicity and cognitive impairment in developing brains have become one of the current research hotspots in the medical science community. The underlying mechanisms are complex and involve various related molecular signaling pathways, cell mediators, autophagy, and other pathological processes. However, few drugs can be directly used to treat neurotoxicity and cognitive impairment caused by general anesthetics in clinical practice. This article reviews the molecular mechanism of general anesthesia-induced neurotoxicity and cognitive impairment in the neonatal brain after surgery in the hope of providing critical references for the treatments of clinical diseases.

Inhibition of MicroRNA-182/183 Cluster Ameliorates Schizophrenia by Activating the Axon Guidance Pathway and Upregulating DCC

Schizophrenia (SZ) is a complex disorder caused by a variety of genetic and environmental factors. Mounting evidence suggests the involvement of microRNAs (miRNAs) in the pathology of SZ. Accordingly, the current study set out to investigate the possible implication of the miR-182/183 cluster, as well as its associated mechanism in the progression of SZ. Firstly, rat models of SZ were established by intraperitoneal injection of MK-801. Moreover, rat primary hippocampal neurons were exposed to MK-801 to simulate injury of hippocampal neurons. The expression of miR-182/183 or its putative target gene DCC was manipulated to examine their effects on SZ in vitro and in vivo. It was found that miR-182 and miR-183 were both highly expressed in peripheral blood of SZ patients and hippocampal tissues of SZ rats. In addition, the miR-182/183 cluster could target DDC and downregulate the expression of DDC. On the other hand, inhibition of the miR-182/183 cluster ameliorated SZ, as evidenced by elevated serum levels of NGF and BDNF, along with reductions in spontaneous activity, serum GFAP levels, and hippocampal neuronal apoptosis. Additionally, DCC was found to activate the axon guiding pathway and influence synaptic activity in hippocampal neurons. Collectively, our findings highlighted that inhibition of the miR-182/183 cluster could potentially attenuate SZ through DCC-dependent activation of the axon guidance pathway. Furthermore, inhibition of the miR-182/183 cluster may represent a potential target for the SZ treatment.

Research progress on the effects and mechanisms of anesthetics on neural stem cells

Exposure to anesthetic drugs has been proven to seriously affect developing animals in terms of neural stem cells' (NSCs') proliferation, differentiation, and apoptosis. This can severely hamper the development of physiological learning and memory skills. Studies on the effects of anesthetics on NSCs' proliferation and differentiation are thus reviewed here, with the aim to highlight which specific drug mechanisms are the least harmful to NSCs. PubMed has been used as the preferential searching database of relevant literature to identify studies on the effects and mechanisms of NSCs' proliferation and differentiation. It was concluded that propofol and sevoflurane may be the safest options for NSCs during pregnancy and in pediatric clinical procedures, while dexmedetomidine has been found to reduce opioid-related damage in NSCs. It was also found that the growth environment may impact neurodevelopment even more than narcotic drugs. Nonetheless, the current scientific literature available further highlights how more extensive clinical trials are absolutely required for corroborating the conclusion drawn here.

Sevoflurane induces microRNA-18a to delay rat neurodevelopment via suppression of the RUNX1/Wnt/β-catenin axis

Sevoflurane anesthesia is reported to repress neurogenesis of neural stem cells (NSCs), thereby affecting the brain development, but the underlying mechanism of sevoflurane on the proliferation of NSCs remains unclear. Thus, this study aims to discern the relationship between sevoflurane and NSC proliferation. Bioinformatics tools were employed to predict the expression of microRNA-18a (miR-18a) in 9-day-old neonatal rat hippocampal tissues after sevoflurane treatment and the downstream genes of miR-18a, followed by a series of assays to explore the relationship among miR-18a, runt related transcription factor 1 (RUNX1), and β-catenin in the hippocampal tissues. NSCs were isolated from the hippocampal tissues and subjected to gain-/loss-of-function assays to investigate the interactions among miR-18a, RUNX1, and β-catenin in NSCs and their roles in NSC development. Bioinformatics analysis and experimental results confirmed high expression of miR-18a in rat hippocampal tissues and NSCs after sevoflurane treatment. Next, we found that miR-18a downregulated RUNX1 expression, while RUNX1 promoted NSC proliferation by activating the Wnt/β-catenin signaling pathway. The behavioral experiments also showed that sevoflurane caused nerve injury in rats, whilst RUNX1 overexpression protected rat neurodevelopment. Our findings uncovered that sevoflurane attenuated NSC proliferation via the miR-18a-meidated RUNX1/Wnt/β-catenin pathway, thereby impairing rat neurodevelopment.

Sevoflurane promotes premature differentiation of dopaminergic neurons in hiPSC-derived midbrain organoids

Background: Conventional animal models used in corresponding basic studies are distinct from humans in terms of the brain’s development trajectory, tissue cytoarchitecture and cell types, making it difficult to accurately evaluate the potential adverse effects of anesthetic treatments on human fetal brain development. This study investigated the effects of sevoflurane on the midbrain’s development and cytopathology using human physiologically-relevant midbrain organoids.

Methods: Monolayer human induced pluripotent stem cells (hiPSC)-derived human floor plate cells and three-dimensional hiPSC-derived midbrain organoids (hMBOs) were exposed to 2% (v/v) sevoflurane for 2 or 6 h, followed by expansion or differentiation culture. Then, immunofluorescence, real-time PCR, EdU assay, Tunnel assay, and transcriptome sequencing were performed to examine the effects of sevoflurane on the midbrain’s development.

Results: We found that 2% sevoflurane exposure inhibited hFPCs’ proliferation (differentiation culture: 7.2% ± 0.3% VS. 13.3% ± 0.7%, p = 0.0043; expansion culture: 48% ± 2.2% VS. 35.2% ± 1.4%, p = 0.0002) and increased their apoptosis, but did not affect their differentiation into human dopaminergic neurons After 6 h, 2% sevoflurane exposure inhibited cell proliferation (62.8% ± 5.6% VS. 100% ± 5.5%, p = 0.0065) and enhanced the premature differentiation of hMBOs (246% ± 5.2% VS. 100% ± 28%, p = 0.0065). The RNA-seq results showed long-term exposure to sevoflurane up regulates some transcription factors in the differentiation of dopaminergic neurons, while short-term exposure to sevoflurane has a weak up-regulation effect on these transcription factors.

Conclusion: This study revealed that long-term exposure to sevoflurane could promote the premature differentiation of hMBOs, while short-term exposure had negligible effects, suggesting that long-term exposure to sevoflurane in pregnant women may lead to fetals’ midbrain development disorder.

Identification of Prefrontal Cortex and Amygdala Expressed Genes Associated With Sevoflurane Anesthesia on Non-human Primate

Clinical trials and animal studies have indicated that long-term use or multiple administrations of anesthesia may lead to fine motor impairment in the developing brain. Most studies on anesthesia-induced neurotoxicity have focused on the hippocampus and prefrontal cortex (PFC); however, the role of other vital encephalic regions, such as the amygdala, is still unclear. Herein, we focused on sevoflurane, the most commonly used volatile anesthetic in infants, and performed a transcriptional analysis of the PFC and amygdala of macaques after multiple exposures to the anesthetic by RNA sequencing. The overall, overlapping, and encephalic region-specific transcriptional patterns were separately analyzed to reveal their functions and differentially expressed gene sets that were influenced by sevoflurane. Specifically, functional, protein–protein interaction, neighbor gene network, and gene set enrichment analyses were performed. Further, we built the basic molecular feature of the amygdala by comparing it to the PFC. In comparison with the amygdala’s changing pattern following sevoflurane exposure, functional annotations of the PFC were more enriched in glial cell-related biological functions than in neuron and synapsis development. Taken together, transcriptional studies and bioinformatics analyses allow for an improved understanding of the primate PFC and amygdala.

miR-424 inhibits apoptosis and inflammatory responses induced by sevoflurane through TLR4/MyD88/NF-κB pathway

BACKGROUND

Side effects of sevoflurane in anterograde and retrograde memory have been widely reported. However, there is no convincing evidence that sevoflurane directly causes the development of neurotoxicity. miR-424 has the potential to regulate the neurotoxicity caused by isoflurane anesthesia, and it has a complementary sequence with the 3'UTR region of TLR4. Thus, our study aims to explore whether sevoflurane directly causes neurotoxicity, the effects of miR-424 on sevoflurane induced apoptosis and inflammation, and the underlying mechanism.

METHODS

Sevoflurane effects were identified both in mouse and in PC12 cells. Western blots and ELISA were used for protein detection, while micro (mi) RNA expression was measured with RT-qPCR. Dual luciferase reporter assays were employed to study the interaction between miR-424 and Toll-like receptor 4 (TLR4) using miR-424 mimics and TLR4 over-expression.

RESULTS

Sevoflurane stimulated expression of Bax2 and Caspase-3, and increased apoptosis ratio both in vivo and vitro (P < 0.05). Inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6, were up-regulated by sevoflurane, while IL-10 was downregulated (P < 0.05). Sevoflurane treatment enhanced the phosphorylation of NF-κB, and up-regulated the expressions of TLR4 and MyD88 (P < 0.05), which demonstrated that sevoflurane inhibited proliferation and differentiation of neuronal cells by activating TLR4/MyD88/NF-κB signaling both in vitro and vivo. However, up-regulation of miR-424 attenuated the negative effects of sevoflurane by targeting the 3'-untranslated region (UTR) of TLR4 and inducing the degradation of mRNA (P < 0.05).

CONCLUSIONS

In vitro, sevoflurane induces activation of the endogenous TLR4 signaling pathway, thereby promoting apoptosis and inflammatory cytokine expression. Exogenous TLR4 acts as an agonist to stimulate TLR4 signaling, whereas miR-424 inhibits both endogenous and exogenous TLR4 signaling, thereby preserving proliferation and differentiation of neuronal cells.

Sevoflurane blocks glioma malignant development by upregulating circRELN through circRELN-mediated miR-1290/RORA axis

Background

Sevoflurane (Sev) has been reported to inhibit cancer development, and sevoflurane treatment in cancers is implicated with the deregulation of specific non-coding RNAs (ncRNAs). This study aimed to investigate the relationship between sevoflurane and circular RNA reelin (circRELN) in glioma.

Methods

The expression of circRELN, microRNA-1290 (miR-1290) and RAR-related orphan receptor A (RORA) was measured by quantitative real-time PCR (qPCR). Cell proliferative capacity was assessed by cell counting kit-8 (CCK-8) and colony formation assays. Cell apoptosis and cell cycle distribution were monitored by flow cytometry assay. Cell migration was assessed by wound healing assay and transwell assay, and cell invasion was assessed by transwell assay. The protein levels of matrix metalloproteinase-2 (MMP2), MMP9 and RORA were quantified by western blot. Tumor growth in vivo was assessed by Xenograft models. The binding relationship between miR-1290 and circRELN or RORA was verified by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay.

Results

We found that circRELN expression was declined in glioma tissues and cells, while Sev treatment enhanced circRELN expression. In function, Sev notably inhibited glioma cell proliferation, migration and invasion and promoted apoptosis and cell cycle arrest, while circRELN knockdown reversed these effects. MiR-1290 served as a target of circRELN, and glioma cell malignant phenotypes recovered by circRELN knockdown were partly repressed by miR-1290 deficiency. In addition, RORA was a target of miR-1290, and glioma cell malignant phenotypes promoted by miR-1290 restoration were partly blocked by RORA overexpression. CircRELN regulated RORA expression by targeting miR-1290. In Xenograft models, Sev inhibited tumor growth by upregulating circRELN.

Conclusion

Sev blocked the progression of glioma by increasing circRELN expression, and circRELN played roles in glioma partly by regulating the miR-1290/RORA network.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01427-1.

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.

DNA damage assessment in peripheral blood of Swiss albino mice after combined exposure to volatile anesthetics and 1 or 2 Gy radiotherapy in vivo

PURPOSE

Patient immobilization by general volatile anesthesia (VA) may be necessary during medical radiology treatment, and its use has increased in recent years. Although ionizing radiation (IR) is a well-known genotoxic and cytotoxic agent, and VA exposure has caused a range of side effects among patients and occupationally exposed personnel, there are no studies to date comparing DNA damage effects from combined VA and single fractional IR dose exposure.

MATERIAL AND METHODS

We investigate whether there is a difference in white blood cells DNA damage response (by the alkaline comet assay) in vivo in 185 healthy Swiss albino mice divided into 37 groups, anesthetized with isoflurane/sevoflurane/halothane and exposed to 1 or 2 Gy of IR. Blood samples were taken after 0, 2, 6 and 24 h after exposure, and comet parameters were measured: tail length, tail intensity and tail moment. The cellular DNA repair index was calculated to quantify the efficiency of cells in repairing and re-joining DNA strand breaks following different treatments.

RESULTS

In combined exposures, halothane caused higher DNA damage levels that were dose-dependent; sevoflurane damage increase did not differ significantly from the initial 1 Gy dose, and isoflurane even demonstrated a protective effect, particularly in the 2 Gy dose combined exposure. Nevertheless, none of the exposures reached control levels even after 24 h.

CONCLUSION

Halothane appears to increase the level of radiation-induced DNA damage, while sevoflurane and isoflurane exhibited a protective effect. DNA damage may have been even greater in target organs such as liver, kidney or even the brain, and this is proposed for future study.

Sevoflurane-Induced Neuroapoptosis in Rat Dentate Gyrus Is Activated by Autophagy Through NF-κB Signaling on the Late-Stage Progenitor Granule Cells

OBJECTIVE

The mechanisms by which exposure of the late-stage progenitor cells to the anesthesia sevoflurane alters their differentiation are not known. We seek to query whether the effects of sevoflurane on late-stage progenitor cells might be regulated by apoptosis and/or autophagy.

METHODS

To address the short-term impact of sevoflurane exposure on granule cell differentiation, we used 5-bromo-2-deoxyuridine (BrdU) to identify the labeled late-stage progenitor granule cells. Male or female rats were exposed to 3% sevoflurane for 4 h when the labeled granule cells were 2 weeks old. Differentiation of the BrdU-labeled granule cells was quantified 4 and 7 days after exposure by double immunofluorescence. The expression of apoptosis and autophagy in hippocampal dentate gyrus (DG) was determined by western blot and immunofluorescence. Western blot for the expression of NF-κB was used to evaluate the mechanism. Morris water maze (MWM) test was performed to detect cognitive function in the rats on postnatal 28-33 days.

RESULTS

Exposure to sevoflurane decreased the differentiation of the BrdU-labeled late-stage progenitor granule cells, but increased the expression of caspase-3, autophagy, and phosphorylated-P65 in the hippocampus of juvenile rats and resulted in cognitive deficiency. These damaging effects of sevoflurane could be mitigated by inhibitors of autophagy, apoptosis, and NF-κB. The increased apoptosis could be alleviated by pretreatment with the autophagy inhibitor 3-MA, and the increased autophagy and apoptosis could be reduced by pretreatment with NF-κB inhibitor BAY 11-7085.

CONCLUSION

These findings suggest that a single, prolonged sevoflurane exposure could impair the differentiation of late-stage progenitor granule cells in hippocampal DG and cause cognitive deficits possibly via apoptosis activated by autophagy through NF-κB signaling. Our results do not preclude the possibility that the affected differentiation and functional deficits may be caused by depletion of the progenitors pool.

NURR1 Alterations in Perinatal Stress: A First Step towards Late-Onset Diseases? A Narrative Review

Perinatal life represents a delicate phase of development where stimuli of all sorts, coming to or from the mother, can influence the programming of the future baby's health. These stimuli may have consequences that persist throughout adulthood. Nuclear receptor related 1 protein (NURR1), a transcription factor with a critical role in the development of the dopaminergic neurons in the midbrain, mediates the response to stressful environmental stimuli in the perinatal period. During pregnancy, low-grade inflammation triggered by maternal obesity, hyperinsulinemia or vaginal infections alters NURR1 expression in human gestational tissues. A similar scenario is triggered by exposure to neurotoxic compounds, which are associated with NURR1 epigenetic deregulation in the offspring, with potential intergenerational effects. Since these alterations have been associated with an increased risk of developing late-onset diseases in children, NURR1, alone, or in combination with other molecular markers, has been proposed as a new prognostic tool and a potential therapeutic target for several pathological conditions. This narrative review describes perinatal stress associated with NURR1 gene deregulation, which is proposed here as a mediator of late-onset consequences of early life events.

Maternal sevoflurane exposure affects differentiation of hippocampal neural stem cells by regulating miR-410-3p and ATN1

BACKGROUND

Currently, numerous animal studies have shown that exposure to commonly used general anesthetics during pregnancy may cause neurocognitive impairment in the offspring. Reportedly, exposure to sevoflurane during mid-trimester of pregnancy can inhibit proliferation of neural stem cells (NSCs) and lead to early apoptosis. Whether exposure to sevoflurane during pregnancy affects the differentiation of NSCs remains unclear.

METHODS

In the present study, pregnant rats were exposed to 3% sevoflurane once for 2 h on gestational day 14 (G14) or 3 times for 2 h on G13, G14, and G15. Next, the differentiation of NSCs was measured using neuron marker β-tubulin III and astrocyte marker glial fibrillary acidic protein (GFAP) in fetal brain tissues 24 h and 72 h after anesthesia and in hippocampus on postnatal day 28. Primary cultured rat NSCs were exposed to 4.1% sevoflurane to explore the mechanism.

RESULTS

The results showed that during mid-trimester, multiple exposures to sevoflurane can cause premature differentiation of NSCs in developing brains of offspring and lead to long-term neuron reduction and astrocyte proliferation in hippocampus. The data from the present study indicated that repeated exposure to sevoflurane downregulated atrophin-1 (ATN1) expression and caused early differentiation of NSCs. Overexpression of ATN1 via lentivirus transfection attenuated the influence of sevoflurane. Using dual luciferase assay, ATN1 was found to be a target gene of microRNA-410-3p (miR-410-3p). MiR-410-3p suppression via lentivirus transfection recovered the ATN1 expression and differentiation of NSCs.

CONCLUSIONS

The results from the present study demonstrated that repeated exposure to sevoflurane leads to early differentiation of NSCs and long-term effects via the miR-410-3p/ATN1 pathway.

Comparative transcriptome analysis of transcultured human skin-derived precursors (tSKPs) from adherent monolayer culture system and tSKPs-derived fibroblasts (tFBs) by RNA-Seq

Transcultured human skin derived precursors (tSKPs) from adherent monolayer culture system have similar characteristics as traditional skin derived precursors (SKPs), making tSKPs a suitable candidate for regenerative medicine. tSKPs can differentiate into fibroblasts. However, little is known about the molecular mechanism of the transition from tSKPs to fibroblasts. Here, we compared the transcriptional profiles of human tSKPs and tSKPs-derived fibroblasts (tFBs) by RNA-Sequence aiming to determine the candidate genes and pathways involving in the differentiation process. A total of 1042 differentially expressed genes (DEGs) were identified between tSKPs and tFBs, with 490 genes up-regulated and 552 genes down-regulated. Our study showed that these DEGs were significantly enriched in tumor necrosis factor signaling pathway, focal adhesion, extracellular matrix-receptor interaction and phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) signaling pathway. A further transcription factors (TFs) analysis of DEGs revealed the significantly down-expressed TFs (p21, Foxo1and Foxc1) in tFBs were mostly the downstream nodes of PI3K-Akt signaling pathway, which suggested PI3K-Akt signaling pathway might play an important role in tSKPs differentiation. The results of our study are useful for investigating the molecular mechanisms in tSKPs differentiation into tFBs, making it possible to take advantage of their potential application in regenerative medicine.

Sevoflurane inhibits the proliferation and invasion of hepatocellular carcinoma cells through regulating the PTEN/Akt/GSK‑3β/β‑catenin signaling pathway by downregulating miR‑25‑3p

Sevoflurane (Sevo) is one of the most frequently used volatile anesthetic agents in surgical oncology and has various effects on tumors, including inhibiting tumor growth, recurrence, and metastases; however, the molecular mechanisms are unknown. This study tried to investigate the influence of Sevo on hepatocellular carcinoma (HCC) cells and its possible mechanisms of action. The present study found that Sevo suppressed both the proliferative and invasive capabilities of both HCCLM3 and Huh7 cells in a dose-dependent manner. Moreover, 53 differentially expressed microRNAs (miRNAs/miRs) in HCC cells that resulted from Sevo were screened out using miRNA microarray assay. In particular, miR-25-3p displayed a significant decrease in response to Sevo treatment. Further studies showed that Sevo's inhibitory actions on HCC cells were attenuated by overexpression of miR-25-3p but enhanced by its inhibitor. Phosphatidylinositol 3,4,5-trisphosphate 3-phosphatase and dual-specificity protein phosphatase PTEN (PTEN), a tumor suppressor gene, was directly targeted by miR-25-3p and its expression was upregulated by Sevo. In addition, Sevo suppressed the expression of phosphorylated-protein kinase B (p-Akt) (S473), glycogen synthase kinase (GSK) 3β (p-GSK3β) (S9), β-catenin, c-Myc and matrix metalloproteinase 9; whereas these inhibitory effects were reversed by miR-25-3p overexpression. More importantly, Sevo's tumor-suppressive effects were enhanced by LY294002 (a PI3-kinase inhibitor) but weakened by insulin growth factor-1 (an agonist of the Akt signaling pathway). These data suggest that Sevo's antitumor effects on HCC could be explained, in part, by Sevo inhibiting the miR-25-3p/PTEN/Akt/GSK-3β/β-catenin signaling pathway.

MicroRNA-325-3p prevents sevoflurane-induced learning and memory impairment by inhibiting Nupr1 and C/EBPβ/IGFBP5 signaling in rats

Endoplasmic reticulum stress-induced neuronal apoptosis contributes to neurotoxicity observed after sevoflurane exposure. However, the molecular mechanism underlying the resulting learning and memory impairments remains unknown. Here, we investigated the roles of miR-325-3p and Nupr1 in sevoflurane-induced learning and memory impairments in neonatal rats and HCN-2 human cortical neuronal cells. We found that in both neonatal rats and HCN-2 cells, sevoflurane exposure impairs learning and memory in neonatal rats and increases expression of Nupr1, the endoplasmic reticulum stress marker proteins C/EBPβ and IGFBP5, and the apoptosis-related protein markers cleaved-Caspase-3 and Bax. Using bioinformatics tools to identify microRNAs that bind to Nupr1, we found that miR-325-3p is downregulated in hippocampal neurons exposed to sevoflurane. Moreover, Nupr1 knockdown and miR-325-3p overexpression improved the rats’ performance in learning and memory tests and reduced sevoflurane-induced apoptosis in vitro and in vivo. These results suggest that miR-325-3p blocks sevoflurane-induced learning and memory impairments by inhibiting Nupr1 and the downstream C/EBPβ/IGFBP5 signaling axis in neonatal rats. MiR-325-3p may therefore be a useful therapeutic target in sevoflurane-induced neurotoxicity.

NR4A2 Exacerbates Cerebral Ischemic Brain Injury via Modulating microRNA-652/Mul1 Pathway

BACKGROUND

Nuclear receptor subfamily group A member 2 (NR4A2), a transcription factor, was suggested to be involved in the pathogenesis of ischemic stroke. Nevertheless, the specific role of NR4A2 in ischemic brain injury has yet to be elucidated. Our aim was to probe the mechanisms behind the repression of microRNA (miRNA) expression resulting from NR4A2 regulation in ischemic brain injury.

METHODS

A rat model with transient global cerebral ischemia (tGCI) was established, followed by HE staining and immunohistochemistry for verification. Subsequently, NR4A2 expression in rat brain tissues was detected by RT-qPCR, Western blot and immunohistochemistry. Then, PC12 cells were treated with NR4A2 alteration and subjected to oxygen-glucose deprivation (OGD) for cerebral ischemia simulation. Cell viability, apoptosis and cycle distribution were detected by CCK-8 and flow cytometry, respectively. miR-652 expression in rat brain tissues and cells was then detected by RT-qPCR, and then the targeting mRNAs of miR-652 were predicted through bioinformatic websites. Finally, the effect of miR-652 and mitochondrial E3 ubiquitin ligase 1 (Mul1) on the PC12 cell activity after OGD treatment was verified by rescue experiments.

RESULTS

NR4A2 and Mul1 were expressed highly in brain tissues of rats with tGCI, while miR-652 was expressed poorly. NR4A2 inhibited the expression of miR-652 by transcription, thus blocking the inhibition of miR-652 on Mul1 to repress PC12 cell activity and promote apoptosis and G0/G1 cell cycle arrest.

CONCLUSION

The transcription factor NR4A2 mediates the expression of Mul1 through transcriptional repression of miR-652, thus promoting ischemic brain injury.

Long non-coding RNA Peg13 attenuates the sevoflurane toxicity against neural stem cells by sponging microRNA-128-3p to preserve Sox13 expression

BACKGROUND

Exposure to anesthetics during brain development may impair neurological function, however, the mechanisms underlying anesthetic neurotoxicity are unclear. Recent studies indicate that long non-coding RNAs (lncRNAs) are crucial for regulating the functional brain development during neurogenesis. This study aimed to determine the regulatory effects and potential mechanisms of lncRNA Peg13 (Peg13) on sevoflurane exposure-related neurotoxicity against neural stem cells (NSCs).

METHODS

Mouse embryotic NSCs were isolated and their self-renewal and differentiation were characterized by immunofluorescence. NSCs were exposed to 4.1% sevoflurane 2 h daily for three consecutive days. The potential toxicities of sevoflurane against NSCs were evaluated by neurosphere formation, 5-ethynyl-2'-deoxyuridine (EdU) incorporation and flow cytometry assays. The Peg13, miR-128-3p and Sox13 expression in NSCs were quantified. The potential interactions among Peg13, miR-128-3p and Sox13 were analyzed by luciferase reporter assay. The effects of Peg13 and/or miR-128-3p over-expression on the sevoflurane-related neurotoxicity and Sox13 expression were determined in NSCs.

RESULTS

The isolated mouse embryotic NSCs displayed potent self-renewal ability and differentiated into neurons, astrocytes and oligodendrocytes in vitro, which were significantly inhibited by sevoflurane exposure. Sevoflurane exposure significantly down-regulated Peg13 and Sox13, but enhanced miR-128-3p expression in NSCs. Transfection with miR-128-3p mimics, but not the control, significantly mitigated the Peg13 or Sox13-regulated luciferase expression in 293T cells. Peg13 over-expression significantly reduced the sevoflurane-related neurotoxicity and increased Sox13 expression in NSCs, which were mitigated by miR-128-3p transfection.

CONCLUSION

Such data indicated that Peg13 mitigated the sevoflurane-related neurotoxicity by sponging miR-128-3p to preserve Sox13 expression in NSCs.

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.

Isolation, Characterization, and Safety Evaluation of Human Skin-Derived Precursors from an Adherent Monolayer Culture System

BACKGROUND

Skin-derived precursors (SKPs) are promising candidates for regenerative medicine. Several studies have transcultured human SKPs (termed tSKPs) from fibroblasts (FBs) expanded in monolayer culture. Herein, we optimized the procedure by treating flasks with poly-2-hydroxyethyl methacrylate (poly-HEMA).

METHODS

tSKPs generated from our adherent monolayer culture system were investigated for protein expression and differentiation capacity. The aggregated cells and the proliferative cells within tSKP spheres were detected by mix-culturing FBs expressing two different fluorescent proteins and BrdU- or EdU-positive cells, respectively. To distinguish tSKPs from FBs, we compared their phenotypes and transcriptomes. The tumorigenicity of tSKPs and FBs was also assessed in our study.

RESULTS

tSKPs expressed Versican, Fibronectin, Vimentin, Sox2, and Nestin. Under appropriate stimuli, tSKPs could differentiate to mesenchymal or neural lineages. While these spheres were heterogeneous populations consisting of both proliferative and aggregated cells, the rate of proliferative cells correlated with a seeding density. tSKPs, isolated from FBs, were distinctive from FBs in cell cycle, marker expression, neural differentiation potential, and transcript profiles despite the two sharing partial similarity in certain properties. As for tumorigenesis, both tSKPs and FBs could be considered as nontumorigenic ex vivo and in vivo.

CONCLUSION

tSKPs were heterogeneous populations presenting similar characteristics as traditional SKPs, while being different from FBs. The potential mixture of FBs in spheres did not affect the biosafety of tSKPs, as both of which had normal karyotype and nontumorigenicity. Taken together, we suggested tSKPs had potential applications in regenerative medicine.

Knockdown of long noncoding RNA WNT5A-AS restores the fate of neural stem cells exposed to sevoflurane via inhibiting WNT5A/Ryk-ROS signaling

Long noncoding RNAs (lncRNAs) have been implicated in neurogenesis. LncRNA WNT5A-AS is upregulated in neural stem cells (NSCs), the proliferation of which is inhibited by sevoflurane. Thus, we hypothesized that knocking down of lncRNA WNT5A-AS may restore the fate of NSCs exposed to sevoflurane. To test this hypothesis, NSCs obtained from postnatal Sprague-Dawley rats were exposed to 2.4% sevoflurane or control gas for 6 h. Bioinformatics analysis, quantitative PCR and RNA interference technology were used to identify the properties of lncRNA WNT5A-AS. Cell proliferation was assessed using counting a Cell Counting Kit-cell 8 assay, a 5-ethynyl-2'-deoxyuridine incorporation assay, and a plate cloning assay. Cell survival was detected by flow cytometry, which was also used to examine the levels of reactive oxygen species (ROS) and the cell cycle. The levels of WNT5A and receptor tyrosine kinase (Ryk) were measured via Western blotting. LncRNA WNT5A-AS was identified to have low coding potency and to be located on the antisense strand of WNT5A. The level of upregulated lncRNA WNT5A-AS was positively correlated with that of WNT5A in response to sevoflurane exposure. The knockdown of lncRNA WNT5A-AS promoted the proliferation and survival of NSCs, whereas it suppressed the WNT5A/Ryk-ROS signaling and drove cell cycle processes. Taken together, findings strongly suggest that the inhibition of lncRNA WNT5A-AS can rescue the fate of NSCs. In addition, WNT5A/Ryk-ROS signaling might be a downstream target of lncRNA WNT5A-AS.