Identification of miRNAs Involved in the Protective Effect of Sevoflurane Preconditioning Against Hypoxic Injury in PC12 Cells

Possible role of miRNAs in pheochromocytoma pathology - Signaling pathways interaction

Pheochromocytoma (PCC) is a type of neuroendocrine tumor that originates from adrenal medulla or extra-adrenal chromaffin cells and results in the production of catecholamine. Paroxysmal hypertension and cardiovascular crises were among the clinical signs experienced by people with PCC. Five-year survival of advanced-stage PCC is just around 40% despite the identification of various molecular-level fundamentals implicated in these pathogenic pathways. MicroRNAs (miRNAs, miRs) are a type of short, non-coding RNA (ncRNA) that attach to the 3'-UTR of a target mRNA, causing translational inhibition or mRNA degradation. Evidence is mounting that miRNA dysregulation plays a role in the development, progression, and treatment of cancers like PCC. Hence, this study employs a comprehensive and expedited survey to elucidate the potential role of miRNAs in the development of PCC, surpassing their association with survival rates and treatment options in this particular malignancy.

Mechanism underlying sevoflurane-induced protection in cerebral ischemia–reperfusion injury

Cerebral ischemia is an extremely complex disease that can be caused by a variety of factors. Cerebral ischemia can cause great harm to human body. Sevoflurane is a volatile anesthetic that is frequently used in clinic, and has a lot of advantages, such as quick induction of general anesthesia, quick anesthesia recovery, no respiratory tract irritation, muscle relaxation, and small cycle effect. The mechanism of sevoflurane preconditioning or post-treatment induction is poorly understood. The purpose of this study was to illustrate the mechanism underlying sevoflurane-induced protection in cerebral ischemia–reperfusion injury and also provide theoretical guidance for future research.

Effect of sevoflurane on the inflammatory response during cardiopulmonary bypass in cardiac surgery: the study protocol for a randomized controlled trial

Background

Recent experimental evidence shows that sevoflurane can reduce the inflammatory response during cardiac surgery with cardiopulmonary bypass. However, this observation so far has not been assessed in an adequately powered randomized controlled trial.

Methods

We plan to include one hundred patients undergoing elective coronary artery bypass graft with cardiopulmonary bypass who will be randomized to receive either volatile anesthetics during cardiopulmonary bypass or total intravenous anesthesia. The primary endpoint of the study is to assess the inflammatory response during cardiopulmonary bypass by measuring PMN-elastase serum levels. Secondary endpoints include serum levels of other pro-inflammatory markers (IL-1β, IL-6, IL-8, TNFα), anti-inflammatory cytokines (TGFβ and IL-10), and microRNA expression in peripheral blood to achieve possible epigenetic mechanisms in this process. In addition clinical endpoints such as presence of major complications in the postoperative period and length of hospital and intensive care unit stay will be assessed.

Discussion

The trial may determine whether adding volatile anesthetic during cardiopulmonary bypass will attenuate the inflammatory response.

Trial registration

ClinicalTrials.gov NCT02672345. Registered on February 2016 and updated on June 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-020-04809-x.

MicroRNA-153-3p increases autophagy in sevoflurane-preconditioned mice to protect against ischaemic/reperfusion injury after knee arthroplasty

The use of tourniquet during total knee arthroplasty (TKA) can result in ischaemia/reperfusion injury (IRI). Of interest, microRNAs (miRs) are reported to be involved in various kinds of IRI due to their ability in modulating autophagy. Therefore, the study aimed to investigate the effect of miR‐153‐3p on autophagy in IRI in vitro and in vivo under sevoflurane preconditioning. In the in vitro model, chondrocytes from naive mice were treated with 0% FBS alone or in combination with sevoflurane. Additionally, in vivo assays were conducted in mouse models with tourniquet‐induced IRI after TKA under or without sevoflurane preconditioning. The pathological observation in vivo validated that sevoflurane preconditioning protected the knee joint against IRI. Moreover, miR‐153‐3p expression was diminished in chondrocytes of the in vitro model and in cartilage tissue of the in vivo model, but its expression was appreciably up‐regulated in the presence of sevoflurane preconditioning. Mechanistic study showed that miR‐153‐3p disrupted the interaction between Bcl‐2 and Beclin1 by targeting Bcl‐2, thereby facilitating autophagy in chondrocytes under sevoflurane preconditioning. Furthermore, the experiments in human chondrocytes also verified the protective effects of miR‐153‐3p against IRI were realized through inhibiting Bcl‐2. Collectively, miR‐153‐3p overexpression blocks the interaction between Bcl‐2 and Beclin1 via down‐regulation of Bcl‐2 to promote autophagy of chondrocytes, thus protecting knee joint against IRI after TKA under sevoflurane preconditioning.

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.

Long noncoding RNA MEG3 deteriorates inflammatory damage by downregulating microRNA-101a

Valvulopathy is a familiar heart disease, which fearfully harms the health of the body. We studied the effects and mechanism of long noncoding RNA maternally expressed gene 3 (lncMEG3) on MVICs cell in inflammatory damage. Cell Counting Kit-8 and flow cytometry were respectively used to detect the effect of tumor necrosis factor α (TNF-α), MEG3 and microRNA (miR)-101a on cell viability and apoptosis. Moreover, MEG3 and miR-101a expression were changed by cell transfection and investigated by reverse transcription-quantitative polymerase chain reaction. Furthermore, Western blot was used to investigate the levels of Bax, pro-caspase-3, cleaved-caspase-3, pro-caspase-9, cleaved-caspase-9, interleukin (IL)-1β, IL-6 and related-proteins of cell pathways. Otherwise, the levels of IL-1β and IL-6 were also investigated by enzyme-linked immunosorbent assay kit. Reactive oxygen species (ROS) was examined by ROS assay. We found TNF-α caused inflammatory damage and upregulated MEG3. MEG3 was overexpressed and silenced in cells. Besides, MEG3 deteriorated inflammatory damage. Furthermore, MEG3 negatively regulated miR-101a and miR-101a mimic could reverse the effect of pc-MEG3. Besides, MEG3 enhanced the JNK and NF-κB pathways by downregulating miR-101a. In conclusion, MEG3 deteriorated cell inflammatory damage by downregulating miR-101a via JNK and NF-κB pathways.

HDL protects against myocardial ischemia reperfusion injury via miR-34b and miR-337 expression which requires STAT3

Purpose

High density lipoprotein (HDL) protects against myocardial infarction via mechanisms that remain unclear. STAT3 (signal transducer and activator of transcription 3) plays a key role in HDL-induced cardioprotection. In the heart, microRNAs (miRNAs) are involved in ischemia reperfusion injury. We therefore investigated whether the cardioprotective effect of HDL modulates miRNAs as a downstream target of STAT3 activation.

Methods

STAT3 cardiomyocyte deficient mice (STAT3-KO) and wildtype littermates (STAT3-WT) were submitted to left coronary ligature and reperfused (IR) with or without injection of HDL. Infarct size (IS) was determined and cardiac miRNA expression was evaluated after reperfusion in sham, IR and IR+HDL hearts by microarray analysis.

In vitro, neonatal rat ventricular cardiomyocytes were submitted to hypoxia with or without HDL incubation. Cell viability and miRNA expression were analysed.

Results

In vivo, HDL reduced IS from 40.5±4.3% to 24.4±2.1% (p<0.05) in STAT3-WT mice. HDL failed to protect in STAT3-KO mice. In STAT3-WT mice, both miR-34b and miR-337 were increased in IR compared to sham and IR+HDL groups (p<0.05). These miRNAs were not modulated in STAT3-KO mice. In vitro, incubation with HDL improved cell viability against hypoxia (p<0.05). The expression of miR-34b and miR-337 was increased by hypoxia and reduced by HDL treatment (p<0.05). In cardiomyocytes transfected with miRNA mimics, HDL failed to improve cell viability against hypoxia.

Conclusions

Our study, performed both in vivo and in vitro, delineates a novel cardioprotective signalling pathway activated by HDL, involving STAT3-mediated decrease of miR-34b and miR-337 expression.

Sevoflurane‑induced neurotoxicity is driven by OXR1 post‑transcriptional downregulation involving hsa‑miR‑302e

Sevoflurane is a common anesthetic agent used in surgical settings and previous studies have indicated that it exerts a neurotoxic effect. However, the molecular mechanism underlying this side effect is unknown. In addition, the human microRNA‑302 (hsa‑miR‑302) family members have been reported to be involved in neuronal cell development and biology. Thus, the present study aimed to investigate the potential implication of hsa‑miR‑302e in the sevoflurane‑induced cytotoxicity on human hippocampal cells (HN‑h). HN‑h cells were transfected with hsa‑miR‑302e mimic, hsa‑miR‑302e inhibitor or negative controls and subsequently exposed to different concentrations of sevoflurane. An MTT assay was used to assess the cytotoxicity of sevoflurane on HN‑h cells. Cell apoptosis was determined by flow cytometry. The levels of lactate dehydrogenase release, reactive oxygen species, lipid peroxidation and intracellular calcium (Ca2+) were additionally detected. Reverse transcription‑quantitative polymerase chain reaction and western blotting were conducted to determine mRNA and protein expression, respectively. A luciferase assay was performed for validating the targeting of OXR1 by hsa‑miR‑302e. The results indicated that sevoflurane induced a decrease in cell viability, malondialdehyde and reactive oxygen species production, lactate dehydrogenase release, intracellular Ca2+ production, calcium/calmodulin‑dependent protein kinase II phosphorylation and apoptosis. In addition, treatment with sevoflurane induced the expression of hsa‑miR‑302e while the expression of its target, oxidation resistance gene 1 (OXR1), was significantly downregulated. Inhibition of hsa‑miR‑302e expression protected neuronal cells from sevoflurane cytotoxicity. Mechanistic studies demonstrated that OXR1 was a direct target of hsa‑miR‑302e. Furthermore, the overexpression of OXR1 abolished the effect of sevoflurane on neuronal cells. The results of the present study indicated that sevoflurane exerts its neurotoxic effect by regulating the hsa‑miR‑302e/OXR1 axis. Therefore, the manipulation of the hsa‑miR‑302e/OXR1 pathway will be useful for preventing sevoflurane‑induced neurotoxicity.

Deletion of long noncoding RNA EFNA3 aggravates hypoxia-induced injury in PC-12 cells by upregulation of miR-101a

Long noncoding RNAs (lncRNAs) have been reported to be involved in several neurological pathogenesis conditions including cerebral ischemia. In the current study, the functions of lncRNA EFNA3 on hypoxia-injured rat adrenal pheochromocytoma (PC-12) cells and the underlying molecular mechanism were studied. The expression of lncRNA EFNA3 was silenced by short hairpin RNA transfection, after which the cells were subjected with hypoxia. Cell viability, migration, invasion, and apoptosis were, respectively, determined by trypan blue staining, Transwell assay, annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) double-staining, and Western blot analysis. The cross regulation between lncRNA EFNA3 and miR-101a, as well as between miR-101a and Rho associated coiled-coil containing protein kinase 2 (ROCK2) were detected by performing quantitative real-time polymerase chain reaction, RNA pull-down, RNA immunoprecipitation, luciferase activity assay, and Western blot analysis. Studies showed that lncRNA EFNA3 was highly expressed in response to hypoxia. Deletion of lncRNA EFNA3 significantly aggravated hypoxia-induced injury in PC-12 cells, as the impairment of cell viability, migration, and invasion, and the inducement of apoptosis. LncRNA EFNA3 worked as a sponging molecule for miR-101a and miR-101a suppression-protected PC-12 cells against hypoxia-induced injury even when lncRNA EFNA3 was silenced. ROCK2 was a target gene of miR-101a. ROCK2 overexpression exhibited neuroprotective activities. Besides, ROCK2 overexpression activated Wnt/β-catenin pathway whereas it deactivated JAK/STAT pathway upon hypoxia. Our study suggests that deletion of lncRNA EFNA3 aggravates hypoxia-induced injury in PC-12 cells by upregulating miR-101a, which further targets ROCK2.

MicroRNA Changes in Preconditioning-Induced Neuroprotection

Preconditioning is a paradigm in which sublethal stress-prior to a more injurious insult-induces protection against injury. In the central nervous system (CNS), preconditioning against ischemic stroke is induced by short durations of ischemia, brief seizures, exposure to anesthetics, and other stresses. Increasing evidence supports the contribution of microRNAs (miRNAs) to the pathogenesis of cerebral ischemia and ischemic tolerance induced by preconditioning. Studies investigating miRNA changes induced by preconditioning have to date identified 562 miRNAs that change expression levels after preconditioning, and 15% of these changes were reproduced in at least one additional study. Of miRNAs assessed as changed by preconditioning in more than one study, about 40% changed in the same direction in more than one study. Most of the studies to assess the role of specific miRNAs in the neuroprotective mechanism of preconditioning were performed in vitro, with fewer studies manipulating individual miRNAs in vivo. Thus, while many miRNAs change in response to preconditioning stimuli, the mechanisms underlying their effects are not well understood. The data does suggest that miRNAs may play significant roles in preconditioning-induced neuroprotection. This review focuses on the current state of knowledge of the possible role of miRNAs in preconditioning-induced cerebral protection.

Sevoflurane downregulates IGF‑1 via microRNA‑98

Insulin-like growth factor (IGF)-1 functions as a neuroprotective hormone and may protect against cognitive impairment, which may occur as a result of sevoflurane exposure. The aim of the present study was to assess the effect of sevoflurane on the production of IGF‑1 and investigate the molecular mechanisms underlying this regulation. The BRL rat hepatocyte cell line and adult mice were exposed to 1 or 2 minimal alveolar concentrations sevoflurane for 4 or 8 h. IGF‑1 and microRNA‑98 levels were quantified using an enzyme‑linked immunosorbent assay, western blotting and reverse transcription‑quantitative polymerase chain reaction analyses. The importance of microRNA‑98 in the regulation of IGF‑1 by sevoflurane was investigated using a microRNA‑98 inhibitor. Sevoflurane treatment reduced IGF‑1 levels and simultaneously upregulated microRNA‑98 expression levelsin rat hepatocytes and adult mice. Inhibition of microRNA‑98 attenuated this effect. Therefore, sevoflurane may reduce the synthesis of IGF‑1 by upregulating microRNA‑98 expression.

Non-coding RNAs and neuroprotection after acute CNS injuries

Accumulating evidence indicates that various classes of non-coding RNAs (ncRNAs) including microRNAs (miRNAs), PIWI-interacting RNAs (piRNAs) and long non-coding RNAs (lncRNAs) play important roles in normal state as well as the diseases of the CNS. Interestingly, ncRNAs have been shown to interact with messenger RNA, DNA and proteins, and these interactions could induce epigenetic modifications and control transcription and translation, thereby adding a new layer of genomic regulation. The ncRNA expression profiles are known to be altered after acute CNS injuries including stroke, traumatic brain injury and spinal cord injury that are major contributors of morbidity and mortality worldwide. Hence, a better understanding of the functional significance of ncRNAs following CNS injuries could help in developing potential therapeutic strategies to minimize the neuronal damage in those conditions. The potential of ncRNAs in blood and CSF as biomarkers for diagnosis and/or prognosis of acute CNS injuries has also gained importance in the recent years. This review highlighted the current progress in the understanding of the role of ncRNAs in initiation and progression of secondary neuronal damage and their application as biomarkers after acute CNS injuries.

The Emerging Role of Epigenetics in Cerebral Ischemia

Despite great progresses in the treatment and prevention of ischemic stroke, it is still among the leading causes of death and serious long-term disability all over the world, indicating that innovative neural regenerative and neuroprotective agents are urgently needed for the development of therapeutic approaches with greater efficacy for ischemic stroke. More and more evidence suggests that a spectrum of epigenetic processes play an important role in the pathophysiology of cerebral ischemia. In the present review, we first discuss recent developments in epigenetic mechanisms, especially their roles in the pathophysiology of cerebral ischemia. Specifically, we focus on DNA methylation, histone deacetylase, histone methylation, and microRNAs (miRNAs) in the regulation of vascular and neuronal regeneration after cerebral ischemia. Additionally, we highlight epigenetic strategies for ischemic stroke treatments, including the inhibition of histone deacetylase enzyme and DNA methyltransferase activities, and miRNAs. These therapeutic strategies are far from clinic use, but preliminary data indicate that neuroprotective agents targeting these pathways can modulate neural cell regeneration and promote brain repair and functional recovery after cerebral ischemia. A better understanding of how epigenetics influences the process and progress of cerebral ischemia will pave the way for discovering more sensitive and specific biomarkers and new targets and therapeutics for ischemic stroke.