MicroRNA-27a-3p suppression of peroxisome proliferator-activated receptor-γ contributes to cognitive impairments resulting from sevoflurane treatment

Involvement of selected circulating ncRNAs in the regulation of cognitive dysfunction induced by anesthesia

Post-operative cognitive dysfunction (POCD) refers to the functional impairment of the nervous system caused by prolonged exposure to anesthetics. It is known that prolonged exposure to anesthetics may increase the risk for the development of several cognitive impairments. The drugs used to induce general anesthesia are generally safe, owing to the CNS's direct and/or indirect self-protective activity against drug-induced damages. Non-coding RNAs have recently started to gain attention to better understand the mechanism of gene regulation correlated to cellular physiology and pathology. In order to provide new insights for the neuroprotective function of highly expressed ncRNAs in the central nervous system, we investigated their expression profile in the circulating exosomes of patients exposed to anesthesia vs healthy controls. The experimental design envisaged the recruitment of 30 adult patients undergoing general anesthesia and healthy controls. The effects of anesthetics have been evaluated on miR-34a and miR-124, on the lncRNAs MALAT-1, HOTAIR, GAS5, BLACAT1, HULC, PANDA, and on YRNAs. NcRNAs miR-34a, miR-124, MALAT-1, HOTAIR, GAS5, BLACAT1, and YRNA1 are significantly overexpressed following anesthesia, while YRNA5 is significantly down regulated. Some of them have neuroprotective function, while other correlate with neurological dysfunctions. Our data suggests that, during anesthesia, the toxic action of some non-coding RNAs could be compensated by other non-coding RNAs, both synthesized by the CNS or also transported into neurons from other tissues. It is reasonable to suppose a mutual action of these molecules likely to secure the CNS from anesthetics, that drive a convoluted cascade of ncRNA-dependent biological counter-responses. Our findings are novel in the field of brain dysfunction, indicating that some of the analyzed ncRNAs, although several of their functions still need to be addressed, could be suggested as potential biomarkers and therapeutic targets in post-operative cognitive dysfunction-related processes.

MiR-181a-5p knockdown ameliorates sevoflurane anesthesia-induced neuron injury via regulation of the DDX3X/Wnt/β-catenin signaling axis

Sevoflurane is one of the most widely used inhaled anesthetics. MicroRNAs (miRNAs) have been demonstrated to affect sevoflurane anesthesia-induced neuron damage. The purpose of this study was to investigate the role and mechanism of miR-181a-5p in sevoflurane-induced hippocampal neuronal injury. Primary hippocampal neurons were identified using microscopy and immunofluorescence. The viability and apoptosis of sevoflurane anesthesia-induced neurons were detected by cell counting kit-8 (CCK-8) assay and terminal-deoxynucleoitidyl transferase-mediated nick end-labeling (TUNEL) staining assay, respectively. The levels of apoptosis- and oxidative stress-related proteins as well as the markers in the Wnt/β-catenin signaling pathway were examined by immunoblotting. Enzyme-linked immuno-sorbent assays were performed to examine the levels of inflammatory cytokines. Luciferase reporter assay was conducted to validate the combination between miR-181a-5p and DEAD-box helicase 3, X-linked (DDX3X). Sevoflurane exposure led to significantly inhibited hippocampal neuron viability and elevated miR-181a-5p expression. Knockdown of miR-181a-5p alleviated sevoflurane-induced neuron injury by reducing cell apoptosis, inflammatory response, and oxidative stress. Additionally, DDX3X was targeted and negatively regulated by miR-181a-5p. Moreover, miR-181a-5p inhibitor activated the Wnt/β-catenin pathway via DDX3X in sevoflurane-treated cells. Rescue experiments revealed that DDX3X knockdown or overexpression of Wnt antagonist Dickkopf-1 (DKK1) reversed the suppressive effects of miR-181a-5p inhibitor on cell apoptosis, inflammatory response, and oxidative stress in sevoflurane-treated neuronal cells. MiR-181a-5p ameliorated sevoflurane-triggered neuron injury by regulating the DDX3X/Wnt/β-catenin axis, suggesting the potential of miR-181a-5p as a novel and promising therapeutic target for the treatment of sevoflurane-evoked neurotoxicity.

The Mechanism of Oxymatrine Targeting miR-27a-3p/PPAR-γ Signaling Pathway through m6A Modification to Regulate the Influence on Hemangioma Stem Cells on Propranolol Resistance

OBJECTIVE

The proliferation and migration of hemangioma stem cells (HemSCs) induced apoptosis and adipose differentiation as well as increased the sensitivity of HemSCs to propranolol (PPNL). MiR-27a-3p negatively controlled the peroxisome-proliferator-activated receptor γ (PPAR-γ) level, counteracting the effect of PPAR-γ on HemSC progression and PPNL resistance. OMT accelerated HemSC progression and adipocyte differentiation via modulating the miR-27a-3p/PPAR-γ axis, inhibiting HemSC resistance to PPNL. In tumor-forming experiments, OMT exhibited a dose-dependent inhibitory effect on the volume of IH PPNL-resistant tumors, which was partially dependent on the regulation of m6A methylation transfer enzyme METTL3 and the miR-27a-3p/PPAR-γ axis, thereby inducing apoptosis.

CONCLUSIONS

We conclude that OMT regulates IH and influences PPNL resistance via targeting the miR-27a-3p/PPAR-γ signaling pathway through m6A modification.

MiR-34a targets SIRT1 to reduce p53 deacetylation and promote sevoflurane inhalation anesthesia-induced neuronal autophagy and apoptosis in neonatal mice

This study is to investigate the function of miR-34a and interactions between miR-34a, SIRT1, and p53 in sevoflurane-induced neuronal apoptosis and autophagy in neonatal mice. A mouse model was established by inhalation anesthesia with sevoflurane and injected with genetic reagents, followed by tests of learning and memory abilities and histological staining of the hippocampus. CCK-8 and AnnexinV/PI staining respectively measured the survival and apoptosis rates of primary hippocampal neurons cultured with sevoflurane. The expression levels of miR-34a, SIRT1, p53, Ac-p53, and autophagy- or apoptosis-related proteins were measured. Sevoflurane impaired the learning and memory abilities of mice, increased TUNEL-positive cells in their hippocampus, and hindered the survival of hippocampal neurons. Sevoflurane increased miR-34a, Bax, cleaved caspase-3, and the ratio of LC3-II/LC3-I and reduced SIRT1 and p62. MiR-34a overexpression promoted sevoflurane-induced neural damage, whereas SIRT1 inhibition or p53 upregulation counteracted the neuroprotection of miR-34a knockdown. SIRT1 was a target of miR-34a and promoted p53 deacetylation. MiR-34a promotes sevoflurane-stimulated neuronal apoptosis and autophagy in neonatal mice by inhibiting SIRT1 expression and subsequent p53 deacetylation.

MicroRNAs-Based Theranostics against Anesthetic-Induced Neurotoxicity

Various clinical reports indicate prolonged exposure to general anesthetic-induced neurotoxicity (in vitro and in vivo). Behavior changes (memory and cognition) are compilations commonly cited with general anesthetics. The ability of miRNAs to modulate gene expression, thereby selectively altering cellular functions, remains one of the emerging techniques in the recent decade. Importantly, engineered miRNAs (which are of the two categories, i.e., agomir and antagomir) to an extent found to mitigate neurotoxicity. Utilizing pre-designed synthetic miRNA oligos would be an ideal analeptic approach for intervention based on indicative parameters. This review demonstrates engineered miRNA's potential as prophylactics and/or therapeutics minimizing the general anesthetics-induced neurotoxicity. Furthermore, we share our thoughts regarding the current challenges and feasibility of using miRNAs as therapeutic agents to counteract the adverse neurological effects. Moreover, we discuss the scientific status and updates on the novel neuro-miRNAs related to therapy against neurotoxicity induced by amyloid beta (Aβ) and Parkinson's disease (PD).

Peroxisome Proliferator-Activated Receptor-γ as a Target and Regulator of Epigenetic Mechanisms in Nonalcoholic Fatty Liver Disease

Peroxisome proliferator-activated receptor-γ (PPARγ) belongs to the superfamily of nuclear receptors that control the transcription of multiple genes. Although it is found in many cells and tissues, PPARγ is mostly expressed in the liver and adipose tissue. Preclinical and clinical studies show that PPARγ targets several genes implicated in various forms of chronic liver disease, including nonalcoholic fatty liver disease (NAFLD). Clinical trials are currently underway to investigate the beneficial effects of PPARγ agonists on NAFLD/nonalcoholic steatohepatitis. Understanding PPARγ regulators may therefore aid in unraveling the mechanisms governing the development and progression of NAFLD. Recent advances in high-throughput biology and genome sequencing have greatly facilitated the identification of epigenetic modifiers, including DNA methylation, histone modifiers, and non-coding RNAs as key factors that regulate PPARγ in NAFLD. In contrast, little is still known about the particular molecular mechanisms underlying the intricate relationships between these events. The paper that follows outlines our current understanding of the crosstalk between PPARγ and epigenetic regulators in NAFLD. Advances in this field are likely to aid in the development of early noninvasive diagnostics and future NAFLD treatment strategies based on PPARγ epigenetic circuit modification.

CircUBE3B High Expression Participates in Sevoflurane-Induced Human Hippocampal Neuron Injury via Targeting miR-326 and Regulating MYD88 Expression

The clinical application of Sevoflurane (Sevo) brings about non-negligible neuron injury, leading to postoperative cognitive dysfunction (POCD). However, related pathogenesis is complex and not fully established. We aimed to disclose the role of circRNA UBE3B (circUBE3B) in neuron injury induced by Sevo. Cell viability and apoptosis were determined by CCK-8 and flow cytometry experiments. Inflammation production was monitored by ELISA. The expression of circUBE3B, miR-326, and myeloid differentiation factor 88 (MYD88) mRNA was assessed by quantitative real-time PCR (qPCR). Apoptosis-associated markers and MYD88 protein were quantified by western blot. The putative binding site between miR-326 and circUBE3B or MYD88 was verified by a dual-luciferase reporter experiment, and their binding was validated by a pull-down assay. Sevo treatment weakened cell viability and promoted cell apoptosis and inflammatory response. CircUBE3B expression was elevated in Sevo-treated neurons. Sevo-induced neuron injury was alleviated by circUBE3B downregulation but aggravated by circUBE3B overexpression. MiR-326 was targeted by circUBE3B, and miR-326 inhibition recovered neuron injury that was repressed by circUBE3B absence in Sevo-treated neurons. MiR-326 interacted with MYD88. MiR-326 enrichment attenuated Sevo-induced neuron injury, while these effects were reversed by MYD88 overexpression. CircUBE3B dysregulation was involved in Sevo-induced human hippocampal neuron injury via targeting the miR-326/MYD88 network.

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.

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.

m6A Methyltransferase METTL3 Reduces Hippocampal Neuron Apoptosis in a Mouse Model of Autism Through the MALAT1/SFRP2/Wnt/β-catenin Axis

OBJECTIVE

Hippocampal neuron apoptosis contributes to autism, while METTL3 has been documented to possess great potentials in neuron apoptosis. Our study probed into the role of METTL3 in neuron apoptosis in autism and to determine the underlying mechanism.

METHODS

Bioinformatics analysis was used to analyze expressed genes in autism samples. Institute of Cancer Research mice were treated with valproic acid to develop autism models. The function of METTL3 in autism-like symptoms in mice was analyzed with behavioral tests and histological examination of their hippocampal tissues. Primary mouse hippocampal neurons were extracted for in vitro studies. Downstream factors of METTL3 were explored and validated.

RESULTS

METTL3, MALAT1, and Wnt/β-catenin signaling were downregulated, while SFRP2 was upregulated in the hippocampal tissues of a mouse model of autism. METTL3 stabilized MALAT1 expression by promoting m6A modification of MALAT1. MALAT1 promoted SFRP2 methylation and led to reduced SFRP2 expression by recruiting DNMT1, DNMT3A, and DNMT3B to the promoter region of SFRP2. Furthermore, SFRP2 facilitated activation of the Wnt/β-catenin signaling. By this mechanism, METTL3 suppressed autism-like symptoms and hippocampal neuron apoptosis.

CONCLUSION

This research suggests that METTL3 can reduce autism-like symptoms and hippocampal neuron apoptosis by regulating the MALAT1/SFRP2/Wnt/β-catenin axis.

MicroRNA‑27a Aggravates Ferroptosis during early Ischemic Stroke of Rats Through Nrf2

Ischaemic stroke (IS) is characterized by high morbidity, disability and mortality and lacks effective solutions. MiRNA-27a has been implicated in ferroptosis, but evidence that miRNA-27a regulates ferroptosis in ischaemic stroke is lacking. Nrf2 could reduce brain tissue injury in ischaemic stroke and resist ferroptosis. The current study aimed to investigate the relationship between miRNA-27a/Nrf2 and ferroptosis in ischaemic stroke. In this study, IS was simulated using a permanent middle cerebral artery occlusion (pMCAO) model. The degree of brain tissue injury was assessed by conducting TTC staining and neurological function scoring. MiRNA-27a expression levels were altered via the intracerebroventricular injection of miRNA‑27a agonist or antagonist. Glutathione peroxidase 4 (GPX4), glutathione (GSH), Fe and malondialdehyde (MDA) are considered biomarkers for ferroptosis. The expression of GPX4 and Nrf2 was analysed by Western blot assay. The GSH, Fe and MDA contents were detected by detection kits. We found that the expression levels of Fe and MDA were increased, while GPX4 and GSH were decreased in the pMCAO groups compared with the control group. These results indicated that ferroptosis intensified over time during IS. In addition, the miRNA‑27a agonist significantly aggravated ferroptosis and reduced neurological function scores compared with those of the control group. Subsequently, a luciferase reporter gene system verified the targeted binding of miRNA‑27a to Nrf2. The results showed that miRNA‑27a inhibited Nrf2 in a targeted manner, which also exacerbated the extent of ferroptosis. However, the miRNA‑27a antagonist reversed the miR‑27a agonist‑mediated effects. Therefore, the present study indicated that miRNA‑27a may aggravate brain tissue ferroptosis during ischaemic stroke, potentially by inhibiting Nrf2.

The Role of Epigenetic Modifications in Neurotoxicity Induced by Neonatal General Anesthesia

It has been widely demonstrated by numerous preclinical studies and clinical trials that the neonates receiving repeated or long-time general anesthesia (GA) could develop prolonged cognitive dysfunction. However, the definite mechanism remains largely unknown. Epigenetics, which is defined as heritable alterations in gene expression that are not a result of alteration of DNA sequence, includes DNA methylation, histone post-translational modifications, non-coding RNAs (ncRNAs), and RNA methylation. In recent years, the role of epigenetic modifications in neonatal GA-induced neurotoxicity has been widely explored and reported. In this review, we discuss and conclude the epigenetic mechanisms involving in the process of neonatal anesthesia-induced cognitive dysfunction. Also, we analyze the wide prospects of epigenetics in this field and its possibility to work as treatment target.

Sevoflurane induces inflammation in primary hippocampal neurons by regulating Hoxa5/Gm5106/miR-27b-3p positive feedback loop

Postoperative cognitive dysfunction (POCD) is a normal condition that develops after surgery with anesthesia, leading to deterioration of cognitive functions. However, the mechanism of POCD still remains unknown. To elucidate the POCD molecular mechanism, sevoflurane was employed in the present study to generate neuroinflammation mice model. Sevoflurane treatment caused inflammatory markers IL6, IL-10 and TNF-α high expression in primary hippocampal neurons and blood samples. Long non-coding RNA Gm5106 was found to be increased after being stimulated with sevoflurane. Silencing Gm5106 inhibited neuron inflammation. In the meanwhile, Gm5106 was identified as a direct target of miR-27b-3p that was inhibited by sevoflurane and related to inflammation suppression. In addition, transcription factor (TF) Hoxa5 was validated to activate Gm5106 through two binding motifs in the promoter region after sevoflurane exposure. Furthermore, miR-27b-3p also directly targeted Hoxa5 3'UTR, which affected nuclear Hoxa5 protein served as TF. Hoxa5 protein instead of 3'UTR reduced miR-27b-3p, in which Gm5106 knocking down abrogated this effect. In conclusion, sevoflurane induces neuroinflammation through increasing long non-coding RNA Gm5106, which is transcriptionally activated by Hoxa5 and directly targeted by miR-27-3p. Apart from that, Hoxa5, Gm5106, and miR-27b-3p form a positive feedback loop in sevoflurane stimulation.

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.

The Mechanisms of Sevoflurane-Induced Neuroinflammation

Sevoflurane is one of the most commonly used inhaled anesthetics due to its low blood gas coefficient, fast onset, low airway irritation, and aromatic smell. However, recent studies have reported that sevoflurane exposure may have deleterious effects on cognitive function. Although neuroinflammation was most widely mentioned among the established mechanisms of sevoflurane-induced cognitive dysfunction, its upstream mechanisms have yet to be illustrated. Thus, we reviewed the relevant literature and discussed the most mentioned mechanisms, including the modulation of the microglial function, blood–brain barrier (BBB) breakdown, changes in gut microbiota, and ease of cholinergic neurotransmission to help us understand the properties of sevoflurane, providing us new perspectives for the prevention of sevoflurane-induced cognitive impairment.

Sevoflurane inhibits the apoptosis of hypoxia/reoxygenation-induced cardiomyocytes via regulating miR-27a-3p-mediated autophagy

INTRODUCTION

Sevoflurane (Sevo) prevents hypoxia/reoxygenation (H/R)-induced cardiomyocytes apoptosis. MiR-27a-3p expression is up-regulated in Sevo-treated hippocampal neurons.

OBJECTIVE

This study explored whether the effect of Sevo on cardiomyocytes was mediated by miR-27a-3p.

METHODS

The cardiomyocytes were cultured under H/R condition or pre-treated with Sevo, and further transfected with miR-27a-3p inhibitor or treated with an autophagy inhibitor 3-methyladenine (3-MA). Then the cell morphology was observed under an optical microscope. The cell viability and apoptosis were measured by MTT and flow cytometry. Expressions of miR-27a-3p, apoptosis-related, and autophagy-related factors were determined by western blot or RT-qPCR.

KEY FINDINGS

Sevo improved the abnormal morphology, promoted the cell viability and the expressions of Bcl-2 and miR-27a-3p, but reduced the apoptosis and Bax and C-caspase-3 levels of H/R-induced cardiomyocytes. MiR-27a-3p inhibitor had an effect opposite to Sevo on the cardiomyocytes and further counteracted the effect of Sevo on the H/R-induced cardiomyocytes. Downregulation miR-27a-3p increased the expression of Beclin 1 and the ratio of LC3B-II to LC3B-I in H/R-induced cardiomyocytes. Furthermore, 3-MA had an opposite effect to miR-27a-3p inhibitor and further counteracted the effect of the miR-27a-3p inhibitor on H/R-induced cardiomyocytes.

CONCLUSION

Sevo inhibited the apoptosis of H/R-induced cardiomyocytes via regulating miR-27a-3p-mediated autophagy.

Update on the Mechanism and Treatment of Sevoflurane-Induced Postoperative Cognitive Dysfunction

Sevoflurane is one of the most widely used anesthetics for the induction and maintenance of general anesthesia in surgical patients. Sevoflurane treatment may increase the incidence of postoperative cognitive dysfunction (POCD), and patients with POCD exhibit lower cognitive abilities than before the operation. POCD affects the lives of patients and places an additional burden on patients and their families. Understanding the mechanism of sevoflurane-induced POCD may improve prevention and treatment of POCD. In this paper, we review the diagnosis of POCD, introduce animal models of POCD in clinical research, analyze the possible mechanisms of sevoflurane-induced POCD, and summarize advances in treatment for this condition.

Effect of Chronic Western Diets on Non-Alcoholic Fatty Liver of Male Mice Modifying the PPAR-γ Pathway via miR-27b-5p Regulation

Western diets contribute to metabolic diseases. However, the effects of various diets and epigenetic mechanisms are mostly unknown. Here, six week-old C57BL/6J male and female mice were fed with a low-fat diet (LFD), high-fat diet (HFD), and high-fat high-fructose diet (HFD-HF) for 20 weeks. We determined that HFD-HF or HFD mice experienced significant metabolic dysregulation compared to the LFD. HFD-HF and HFD-fed male mice showed significantly increased body weight, liver size, and fasting glucose levels with downregulated PPARγ, SCD1, and FAS protein expression. In contrast, female mice were less affected by HFD and HFD-HF. As miR-27b contains a seed sequence in PPARγ, it was discovered that these changes are accompanied by male-specific upregulation of miR-27b-5p, which is even more pronounced in the HFD-HF group (p < 0.01 vs. LFD) compared to the HFD group (p < 0.05 vs. LFD). Other miR-27 subtypes were increased but not significantly. HFD-HF showed insignificant changes in fibrosis markers when compared to LFD. Interestingly, fat ballooning in hepatocytes was increased in HFD-fed mice compared to HFD-HF fed mice, however, the HFD-HF liver showed an increase in the number of small cells. Here, we concluded that chronic Western diet-composition administered for 20 weeks may surpass the non-alcoholic fatty liver (NAFL) stage but may be at an intermediate stage between fatty liver and fibrosis via miR-27b-5p-induced PPARγ downregulation.

ACE2 Interaction Networks in COVID-19: A Physiological Framework for Prediction of Outcome in Patients with Cardiovascular Risk Factors

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (coronavirus disease 2019; COVID-19) is associated with adverse outcomes in patients with cardiovascular disease (CVD). The aim of the study was to characterize the interaction between SARS-CoV-2 and Angiotensin-Converting Enzyme 2 (ACE2) functional networks with a focus on CVD.

METHODS

Using the network medicine approach and publicly available datasets, we investigated ACE2 tissue expression and described ACE2 interaction networks that could be affected by SARS-CoV-2 infection in the heart, lungs and nervous system. We compared them with changes in ACE-2 networks following SARS-CoV-2 infection by analyzing public data of human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). This analysis was performed using the Network by Relative Importance (NERI) algorithm, which integrates protein-protein interaction with co-expression networks. We also performed miRNA-target predictions to identify which miRNAs regulate ACE2-related networks and could play a role in the COVID19 outcome. Finally, we performed enrichment analysis for identifying the main COVID-19 risk groups.

RESULTS

We found similar ACE2 expression confidence levels in respiratory and cardiovascular systems, supporting that heart tissue is a potential target of SARS-CoV-2. Analysis of ACE2 interaction networks in infected hiPSC-CMs identified multiple hub genes with corrupted signaling which can be responsible for cardiovascular symptoms. The most affected genes were EGFR (Epidermal Growth Factor Receptor), FN1 (Fibronectin 1), TP53, HSP90AA1, and APP (Amyloid Beta Precursor Protein), while the most affected interactions were associated with MAST2 and CALM1 (Calmodulin 1). Enrichment analysis revealed multiple diseases associated with the interaction networks of ACE2, especially cancerous diseases, obesity, hypertensive disease, Alzheimer's disease, non-insulin-dependent diabetes mellitus, and congestive heart failure. Among affected ACE2-network components connected with the SARS-Cov-2 interactome, we identified AGT (Angiotensinogen), CAT (Catalase), DPP4 (Dipeptidyl Peptidase 4), CCL2 (C-C Motif Chemokine Ligand 2), TFRC (Transferrin Receptor) and CAV1 (Caveolin-1), associated with cardiovascular risk factors. We described for the first time miRNAs which were common regulators of ACE2 networks and virus-related proteins in all analyzed datasets. The top miRNAs regulating ACE2 networks were miR-27a-3p, miR-26b-5p, miR-10b-5p, miR-302c-5p, hsa-miR-587, hsa-miR-1305, hsa-miR-200b-3p, hsa-miR-124-3p, and hsa-miR-16-5p.

CONCLUSION

Our study provides a complete mechanistic framework for investigating the ACE2 network which was validated by expression data. This framework predicted risk groups, including the established ones, thus providing reliable novel information regarding the complexity of signaling pathways affected by SARS-CoV-2. It also identified miRNAs that could be used in personalized diagnosis in COVID-19.

Lipopolysaccharide inhibits triglyceride synthesis in dairy cow mammary epithelial cells by upregulating miR-27a-3p, which targets the PPARG gene

The fat content of milk determines the quality of milk, and triglycerides are the major components of milk fat. Milk fat synthesis is regulated by many factors. Lipopolysaccharide (LPS) has been shown to inhibit milk fat synthesis in bovine mammary epithelial cells, but research on the underlying mechanisms has been limited. MicroRNA (miRNA) are involved in many physiological processes, but there have been few studies on their regulation in milk fat synthesis. In this study, we aimed to investigate whether LPS upregulates miR-27a-3p, which targets PPARG, thereby inhibiting the synthesis of triglycerides in a dairy cow mammary epithelial cell line (MAC-T). After LPS stimulation of MAC-T cells, PPARG gene expression and milk fat synthesis were inhibited. TargetScan software was used to predict miRNA targeting PPARG, and miR-27a-3p was selected as a candidate. A dual luciferase reporter assay further confirmed the targeting connection between miR-27a-3p and the PPARG gene. To investigate the functions of miR-27a-3p, miR-27a-3p mimic and inhibitors were transfected into MAC-T cells. The mRNA and protein levels of PPAR-γ were negatively correlated with the expression of miR-27a-3p. Lipid droplet accumulation and triglyceride synthesis were also negatively correlated with miR-27a-3p expression. Inhibition of miR-27a-3p partially reversed the LPS-induced decreases in PPARG expression and milk fat synthesis. In summary, our results reveal that LPS can inhibit MAC-T cell milk fat synthesis by upregulating miR-27a-3p, which targets the PPARG gene.

hsa_circ_0026827 Promotes Osteoblast Differentiation of Human Dental Pulp Stem Cells Through the Beclin1 and RUNX1 Signaling Pathways by Sponging miR-188-3p

Previous studies have found that circular RNA (circRNA) hsa_circ_0026827 plays a role during osteoblast differentiation, but the mechanism is unclear. The aim of this study was to illuminate the role of hsa_circ_0026827 in human dental pulp stem cells (DPSCs) during osteoblast differentiation. The results show that hsa_circ_0026827 expression significantly increased during osteoblast differentiation, while knockdown of hsa_circ_0026827 suppressed DPSC-derived osteoblast differentiation. microRNA (miRNA) expression profile analysis showed that downregulation of hsa_circ_0026827 promoted miR-188-3p expression. miR-188-3p downregulation restored osteogenic differentiation of DPSCs after hsa_circ_0026827 was silenced. Luciferase reporter assays verified that miR-188-3p was the target of hsa_circ_0026827 and also demonstrated that Beclin1 and RUNX1 were miR-188-3p downstream targets. miR-188-3p overexpression suppressed DPSC osteogenic differentiation by targeting Beclin-1-mediated autophagy and runt-related transcription factor 1 (RUNX1). In vivo studies using a heterotopic bone model also found that hsa_circ_0026827 overexpression plays an important role in promoting heterotopic bone formation. In conclusion, our research indicates that hsa_circ_0026827 promotes osteoblast differentiation of DPSCs via Beclin1 and the RUNX1 signaling pathways by sponging miR-188-3p, which suggests novel therapeutics for osteoporosis treatment.

Long noncoding RNA small nucleolar RNA host gene 1 contributes to sevoflurane-induced neurotoxicity through negatively modulating microRNA-181b

Sevoflurane has been reported to promote learning and memory disabilities by promoting neuroinflammation and neuroapoptosis. However, the precise mechanism by which sevoflurane mediating neurotoxicity remains to be determined. Cell viability, reactive oxygen species (ROS) generation, inflammation and apoptosis were measured by cell counting kit-8 assay, ROS kit, ELISA, flow cytometry and western blot assay. The abundance of small nucleolar RNA host gene 1 (SNHG1) and microRNA-181b (miR-181b) was measured by quantitative real-time PCR in HT22 cells. The binding sites between miR-181b and SNHG1 were predicted by Starbase, and this combination was verified by dual-luciferase reporter assay, RNA immunoprecipitation and RNA-pull down assays. Sevoflurane treatment promoted ROS generation, inflammation and apoptosis while impeded the viability of HT22 cells via upregulating long noncoding RNA (lncRNA) SNHG1. MiR-181b was a direct target of SNHG1, and it was inversely regulated by SNHG1 in HT22 cells. The overexpression of miR-181b counteracted the neurotoxicity of sevoflurane treatment in HT22 cells. MiR-181b depletion abolished the inhibitory effects of SNHG1 intervention on the ROS generation, inflammation and apoptosis and the promoting impact on the viability of HT22 cells. LncRNA SNHG1 contributed neurotoxicity in sevoflurane-stimulated HT22 cells via downregulating miR-181b. The SNHG1/miR-181b axis was a target for the prevention of sevoflurane-induced neurotoxicity.

MicroRNA-27a-3p aggravates renal ischemia/reperfusion injury by promoting oxidative stress via targeting growth factor receptor-bound protein 2

Renal ischemia-reperfusion (RI/R) injury with high morbidity and mortality is one common clinical disease. Development of drug targets to treat the disorder is critical important. MiR-27a-3p plays important roles in regulating oxidative stress. However, its effects on RI/R injury have not been reported. In this paper, hypoxia/reoxygenation (H/R) models on NRK-52E and HK-2 cells, and RI/R model in C57BL/6 mice were established. The results showed that H/R in vitro decreased cell viability and increased ROS levels in cells, and RI/R caused renal injury and oxidative damage in mice. The expression levels of miR-27a-3p were up-regulated based on real-time PCR and FISH assays in model groups compared with control groups, which directly targeted Grb2 based on dual luciferase reporter assay and co-transfaction test. In addition, miR-27a- 3p markedly reduced Grb2 expression to down-regulate the expression levels of p-PI3K, p-AKT, Nrf2, HO-1, and up-regulate Keap1 expression in model groups. MiR-27a-3p mimics in vitro enhanced H/R-caused oxidative stress via increasing ROS levels and decreasing Grb2 expression to down-regulate PI3K-AKT signal. In contrary, miR-27a-3p inhibitor in vitro significantly reduced H/R-caused oxidative damage via decreasing ROS levels and increasing Grb2 expression to up-regulate PI3K-AKT signal. In vivo, miR-27a- 3p agomir exacerbated RI/R-caused renal damage by decreasing SOD level and increasing Cr, BUN, MDA levels via suppressing Grb2 expression to down-regulate PI3K- AKT signal. However, miR-27a -3p antagomir alleviated RI/R-caused oxidative damage via increasing Grb2 expression to up-regulate PI3k-AKT signal. Grb2siRNA in mice further enhanced RI/R-caused renal injury by increasing Cr, BUN, MDA levels and decreasing SOD level via inhibiting the expression levels of Grb2, Nrf2, HO-1, and increasing Keap1 expression. Our data showed that miR-27a-3p aggravated RI/R injury by promoting oxidative stress via targeting Grb2, which should be considered as one new drug target to treat RI/R injury.

Downregulation of CDK5 Restores Sevoflurane-Induced Cognitive Dysfunction by Promoting SIRT1-Mediated Autophagy

An increasing number of studies have found that use of traditional anesthetics may lead to cognitive impairment of the immature brain. Our previous studies verified that cyclin-dependent kinase 5 (CDK5) plays a role in sevoflurane-induced cognitive dysfunction. Autophagy was shown to protect against anesthesia-induced nerve injury. Therefore, the current study aimed to ascertain if autophagy participates in anesthesia-induced neurotoxicity. In this study, primary hippocampal neurons were isolated and utilized for experiments in vitro. We also performed in vivo experiments with 6-day-old wild-type mice treated with or without roscovitine (Rosc, a CDK5 inhibitor) or 3-methyladenine (3-Ma, an autophagy inhibitor) after exposure to sevoflurane. We used the Morris water maze to analyze cognitive function. Immunohistochemical staining was used to assess pathologic changes in the hippocampus. The results showed that suppressing CDK5 reversed sevoflurane-induced nerve cell apoptosis both in vivo and in vitro and demonstrated that inhibits CDK5 activation promoted Sirtuin 1 (Sirt1) expression, which functions importantly in induced autophagy activation. Suppression of Sirt1 expression inhibited the protective effect of Rosc on sevoflurane-induced nerve injury by inhibiting autophagy activation. Our in vivo experiments also found that pretreatment with 3-Ma attenuated the protective effect of Rosc on sevoflurane-induced nerve injury and cognitive dysfunction. We conclude that inhibits CDK5 activation restored sevoflurane-induced cognitive dysfunction by promoting Sirt1-mediated autophagy.

Cistanches alleviates sevoflurane-induced cognitive dysfunction by regulating PPAR-γ-dependent antioxidant and anti-inflammatory in rats

This study aimed to investigate the protective effects and underlying mechanisms of cistanche on sevoflurane‐induced aged cognitive dysfunction rat model. Aged (24 months) male SD rats were randomly assigned to four groups: control group, sevoflurane group, control + cistanche and sevoflurane + cistanche group. Subsequently, inflammatory cytokine levels were measured by ELISA, and the cognitive dysfunction of rats was evaluated by water maze test, open‐field test and the fear conditioning test. Three days following anaesthesia, the rats were killed and hippocampus was harvested for the analysis of relative biomolecules. The oxidative stress level was indicated as nitrite and MDA concentration, along with the SOD and CAT activity. Finally, PPAR‐γ antagonist was used to explore the mechanism of cistanche in vivo. The results showed that after inhaling the sevoflurane, 24‐ but not 3‐month‐old male SD rats developed obvious cognitive impairments in the behaviour test 3 days after anaesthesia. Intraperitoneal injection of cistanche at the dose of 50 mg/kg for 3 consecutive days before anaesthesia alleviated the sevoflurane‐induced elevation of neuroinflammation levels and significantly attenuated the hippocampus‐dependent memory impairments in 24‐month‐old rats. Cistanche also reduced the oxidative stress by decreasing nitrite and MDA while increasing the SOD and CAT activity. Moreover, such treatment also inhibited the activation of microglia. In addition, we demonstrated that PPAR‐γ inhibition conversely alleviated cistanche‐induced protective effect. Taken together, we demonstrated that cistanche can exert antioxidant, anti‐inflammatory, anti‐apoptosis and anti‐activation of microglia effects on the development of sevoflurane‐induced cognitive dysfunction by activating PPAR‐γ signalling.

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.

Suppression of microRNA‑27a protects against liver ischemia/reperfusion injury by targeting PPARγ and inhibiting endoplasmic reticulum stress

Liver ischemia‑reperfusion (I/R) injury is an important clinical issue related to liver transplantation. Recent studies suggest that microRNAs are implicated in various biological and pathological processes, including liver I/R injury. This study aimed to investigate the role and potential mechanism of miR‑27a during liver I/R injury. A liver I/R model was induced via 60 min of ischemia and reperfusion for 6 h in rats. Cells were transfected with miR‑27a mimics or the miR‑27a inhibitor to examine the effect of miR‑27a on liver I/R. Apoptotic cells were detected by flow cytometry and TUNEL staining. The expression of miR‑27a was measured by real‑time PCR. The expression of peroxisome proliferator‑activated receptor γ (PPARγ); gastrin‑releasing peptide 78 (GRP78) and C/EBP homologous protein (CHOP) were detected by western blot analysis. The results showed that miR‑27a was significantly upregulated during I/R injury in vivo and in vitro. In addition, miR‑27a inhibitors attenuated hypoxia/reoxygenation (H/R)‑induced oxidative stress, endoplasmic reticulum stress (ERS) and apoptosis in AML12 cells. By contrast, miR‑27a mimics promoted hypoxia/reoxygenation‑induced ERS, and apoptosis. Furthermore, PPARγ was identified as a target gene of miR‑27a using bioinformatic analysis and a dual‑luciferase reporter assay. Knockdown of PPARγ significantly abrogated the inhibitory effect of miR‑27a inhibitors on the ERS pathway. Moreover, the miR‑27a antagomir attenuated liver I/R injury in rats, a finding manifested by reduced ALT/AST, hepatocyte apoptosis, oxidative stress and inhibition of the ERS pathway. Taken together, these findings demonstrate that suppression of miR‑27a protects against liver I/R injury by targeting PPARγ and by inhibiting the ERS pathway.

Overexpression of lncRNA Gm15621 alleviates apoptosis and inflammation response resulting from sevoflurane treatment through inhibiting miR-133a/Sox4

Sevoflurane is the most widely used anesthetic administered by inhalation. Exposure to sevoflurane can elicit learning deficits and abnormal cognitive disorder. In this study, we investigated the function of long noncoding RNA (lncRNA) Gm15621. Primary hippocampal neuron cells were used to analyze the function of lncRNA Gm15621 in vitro. The tunel, inflammation markers, and cell survival rates were detected to evaluate the function of lncRNA Gm15621. Dual-luciferase reporter assay was used to identify the interaction between microRNA 133a and Gm15621. We found that lncRNA Gm15621 located in the cytoplasm. The expression of lncRNA Gm15621 was decreased with the development of sevoflurane exposure. Overexpression of lncRNA Gm15621 significantly reduced the apoptosis and cell survival rates. The inflammation response was also attenuated in lncRNA Gm15621 overexpressed group. The dual-luciferase assay revealed that miR-133a was the direct target of lncRNA Gm15621. In addition, we also found that Sox4 was a downstream target of miR-133a and lncRNA Gm15621 exerted its biological functions by regulating the expression of Sox4. In summary, our findings revealed that lncRNA Gm15621 ameliorated the sevoflurane-induced neurotoxicity and the important role of Gm15621/miR-133a/Sox4 axis in cognitive disorder.

PPAR-γ: Its ligand and its regulation by microRNAs

Peroxisome proliferator-activated receptors (PPARs) belong to the nuclear receptor superfamily. PPARs are categorized into three subtypes, PPARα, β/δ, and γ, encoded by different genes, expressed in diverse tissues and participate in various biological functions and can be activated by their metabolic derivatives in the body or dietary fatty acids. The PPAR-γ also takes parts in the regulation of energy balance, lipoprotein metabolism, insulin sensitivity, oxidative stress, and inflammatory signaling. It has been implicated in the pathology of numerous diseases including obesity, diabetes, atherosclerosis, and cancers. Among various cellular and molecular targets that are able to regulate PPAR-γ and its underlying pathways, microRNAs (miRNAs) appeared as important regulators. Given that the deregulation of these molecules via targeting PPAR-γ could affect initiation and progression of various diseases, identification of miRNAs that affects PPAR-γ could contribute to the better understanding of roles of PPAR-γ in various biological and pathological conditions. Here, we have summarized the function and various ligands of PPAR-γ and have highlighted various miRNAs involved in the regulation of PPAR-γ.

Sevoflurane alleviates LPS‑induced acute lung injury via the microRNA‑27a‑3p/TLR4/MyD88/NF‑κB signaling pathway

Acute lung injury (ALI) is a critical syndrome that is associated with a high morbidity and mortality in patients. Sevoflurane has a lung protective effect in ALI as it reportedly has anti‑inflammatory and apoptotic‑regulating activity. However, the mechanism is still not entirely understood. The aim of the present study was to explore the effects of sevoflurane on lipopolysaccharide (LPS)‑induced ALI in mice and the possible mechanisms involved. The results revealed that sevoflurane treatment improved LPS‑induced lung injury, as evidenced by the reduction in mortality, lung permeability, lung wet/dry ratio and lung histopathological changes in mice. Total cell counts and the production of pro‑inflammatory cytokines [tumor necrosis factor‑α, interleukin (IL)‑1β and IL‑6] in bronchoalveolar fluid were also decreased following treatment with sevoflurane. Additionally, LPS‑triggered apoptosis in lung tissues, which was eliminated by sevoflurane. Furthermore, a miRCURY™ LNA array was employed to screen for differentially expressed microRNAs (miRs/miRNAs). Among these miRNAs, 6 were differentially expressed and were involved in the inflammatory response, but only miR‑27a‑3p (miR‑27a) was regulated by sevoflurane. Subsequently, the present study investigated whether sevoflurane exerts its function through the modulation of miR‑27a. The results demonstrated that the overexpression of miR‑27a via an injection with agomiR‑27a produced similar protections as sevoflurane, while the inhibition of miR‑27a suppressed the lung protective effects of sevoflurane in ALI mice. In addition, the present study identified that miR‑27a inhibited Toll‑like receptor 4 (TLR4) by binding to its 3'‑untranslated region. Western blot analysis demonstrated that sevoflurane may ameliorate the inflammatory response by blocking the miR‑27a/TLR4/MyD88/NF‑κB signaling pathway. The present results indicate that sevoflurane may be a viable therapeutic option in the treatment of patients with ALI.

LncRNA Rik-203 contributes to anesthesia neurotoxicity via microRNA-101a-3p and GSK-3β-mediated neural differentiation

The mechanism of anesthesia neurotoxicity remains largely to be determined. The effects of long noncoding RNAs (LncRNAs) on neural differentiation and the underlying mechanisms are unknown. We thus identified LncRNA Rik-203 (C130071C03Rik) and studied its role on neural differentiation and its interactions with anesthetic sevoflurane, miRNA and GSK-3β. We found that levels of Rik-203 were higher in hippocampus than other tissues and increased during neural differentiation. Sevoflurane decreased the levels of Rik-203. Rik-203 knockdown reduced mRNA levels of Sox1 and Nestin, the markers of neural progenitor cells, and decreased the count of Sox1 positive cells. RNA-RNA pull-down showed that miR-101a-3p was highly bound to Rik-203. Finally, sevoflurane, knockdown of Rik-203, and miR-101a-3p overexpression all decreased GSK-3β levels. These data suggest that Rik-203 facilitates neural differentiation by inhibiting miR-101a-3p's ability to reduce GSK-3β levels and that LncRNAs would serve as the mechanism of the anesthesia neurotoxicity.

SIRT3 activator honokiol ameliorates surgery/anesthesia-induced cognitive decline in mice through anti-oxidative stress and anti-inflammatory in hippocampus

AIMS

Increasing evidence indicates that neuroinflammatory and oxidative stress play two pivotal roles in cognitive impairment after surgery. Honokiol (HNK), as an activator of Sirtuin3 (SIRT3), has potential multiple biological functions. The aim of these experiments is to evaluate the effects of HNK on surgery/anesthesia-induced cognitive decline in mice.

METHODS

Adult C57BL/6 mice received a laparotomy under sevoflurane anesthesia and HNK or SIRT3 inhibitor (3-TYP) treatment. Cognitive function and locomotor activity of mice were evaluated using fear conditioning test and open field test on postoperative 1 and 3 days. Neuronal apoptosis in CA1 and CA3 area of hippocampus was examined using TUNEL assay. And Western blot was applied to measure the expression of pro-inflammatory cytokines and SIRT3/SOD2 signaling-associated proteins in hippocampus. Meanwhile, SIRT3 positive cells were calculated by immunohistochemistry. The mitochondrial membrane potential, malondialdehyde (MDA), and mitochondrial radical oxygen species (mtROS) were detected using standard methods.

RESULTS

Honokiol attenuated surgery-induced memory loss and neuronal apoptosis, decreased neuroinflammatory response, and ameliorated oxidative damage in hippocampus. Notably, surgery/anesthesia induced an obviously decrease in hippocampal SIRT3 expression, whereas the HNK increased SIRT3 expression and thus decreased the acetylation of superoxide dismutase 2 (SOD2). However, 3-TYP treatment inhibited the HNK's rescuing effects.

CONCLUSIONS

These results suggested that activation of SIRT3 by honokiol may attenuate surgery/anesthesia-induced cognitive impairment in mice through regulation of oxidative stress and neuroinflammatory in hippocampus.