MiR-191 downregulation protects against isoflurane-induced neurotoxicity through targeting BDNF

BDNF Modulation by microRNAs: An Update on the Experimental Evidence

MicroRNAs can interfere with protein function by suppressing their messenger RNA translation or the synthesis of its related factors. The function of brain-derived neurotrophic factor (BDNF) is essential to the proper formation and function of the nervous system and is seen to be regulated by many microRNAs. However, understanding how microRNAs influence BDNF actions within cells requires a wider comprehension of their integrative regulatory mechanisms. Aim: In this literature review, we have synthesized the evidence of microRNA regulation on BDNF in cells and tissues, and provided an analytical discussion about direct and indirect mechanisms that appeared to be involved in BDNF regulation by microRNAs. Methods: Searches were conducted on PubMed.gov using the terms "BDNF" AND "MicroRNA" and "brain-derived neurotrophic factor" AND "MicroRNA", updated on 1 September 2023. Papers without open access were requested from the authors. One hundred and seventy-one papers were included for review and discussion. Results and Discussion: The local regulation of BDNF by microRNAs involves a complex interaction between a series of microRNAs with target proteins that can either inhibit or enhance BDNF expression, at the core of cell metabolism. Therefore, understanding this homeostatic balance provides resources for the future development of vector-delivery-based therapies for the neuroprotective effects of BDNF.

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).

MiR-128-3p Attenuates the Neurotoxicity in Rats Induced by Isoflurane Anesthesia

Isoflurane (ISO) has been widely used in clinical anesthesia, and exposure to ISO leads to cognitive dysfunction. Our paper aimed to investigate the effect of miR-128-3p on cognitive impairment, inflammation, and oxidative stress elicited by ISO anesthesia in Sprague-Dawley (SD) rats. The SD rats were treated with ISO to mimic the ISO-injured situation, and the concentration of miR-128-3p was quantified utilizing real-time PCR. The miR-128-3p's impacts in ISO-engendered rat models on the respects of inflammatory condition and oxidative activities were measured by the commercial kits. The Morris water maze test was adopted to measure the neuro-function regarding miR-128-3p. Additionally, the target was tested by the alternation of luciferase activity. The irritation of ISO suppressed miR-128-3p expression in rats, which was enhanced by the injection of miR-128-3p agomir. The adverse roles of ISO on inflammation, oxidative stress, and cognitive disorders were partially abrogated by an increment of miR-128-3p. A miR-128-3p's interconnection with specificity protein 1 (SP1) was pinpointed, and aggrandized mRNA levels of SP1 were found under ISO state. MiR-128 acted as a regulator in ISO damage in the respects of cognition, inflammation, and oxidative stress. The SP1's link of miR-128-3p was showcased.

Long Non-Coding RNA maternally expressed 3 (MEG3) regulates isoflurane-induced cognitive dysfunction by targeting miR-7-5p

This study aimed to investigate the role and mechanism of long non-coding RNA maternally expressed gene 3 (MEG3) in cognitive dysfunction induced by isoflurane (ISO). Morrier water maze analysis was performed to evaluate the cognitive function of rats. Modified modified neurological severity score (mNSS) scores were assessed for neurological damage. The levels of MEG3 in hippocampal tissues of rats and hippocampal neuron cell lines HT22 were examined by reverse transcription-quantitative polymerase chain reaction (qRT-PCR). Moreover, the cell viability and apoptosis were assessed by the Cell Counting Kit-8 (CCK-8) and flow cytometry assay. Indicators of inflammation and oxidative stress were determined using enzyme-linked immunosorbent assay (ELISA) and commercial assay kits. Relationship between MEG3 and microRNA (miR)-7-5p was verified by the dual-luciferase reporter gene assay. MEG3 was increased in hippocampal tissues and HT22 after ISO treatment (P < 0.05). MEG3 downregulation alleviated the increase in neurological severity score and cognitive dysfunction caused by ISO treatment (P < 0.05). In vitro, MEG3 downregulation alleviates the decrease in cell activity and increased apoptosis induced by ISO. What's more, MEG3 reduction eliminated activation of neuroinflammation and oxidative stress promoted by ISO treatment in rats and HT22 (P < 0.05). MEG3 was confirmed to specifically bind to miR-7-5p. Inhibition of miR-7-5p eliminated the alleviating effects of MEG3 downregulation on cognitive dysfunction caused by ISO treatment. Decreased MEG3 alleviates cognitive dysfunction caused by ISO by targeting miR-7-5p and play a neuroprotective effect. We present a strategy for MEG3 as a potential target for brain protection during anesthesia.

Effects of Long Noncoding RNA H19 on Isoflurane-Induced Cognitive Dysregulation by Promoting Neuroinflammation

INTRODUCTION

Isoflurane (ISO) may cause neuronal apoptosis and synaptic disorder during development, and damage long-term learning and memory function. This observation aimed to study the function of H19 in vitro and in vivo tests and the further mechanism was identified.

METHODS

ISO cell models and rat models were established and reactive oxygen species (ROS) identified. The viability and apoptosis of HT22 cells were detected by the MTT and flow cytometer. Morris water maze test was conducted to analyze the neurotoxicity of ISO on spatial learning and memory ability. Quantitative PCR was the method to verify the expression of H19. The concentration of inflammatory indicators was identified by enzyme-linked immunosorbent assay.

RESULTS

1.5% and 2% ISO led to the neurotoxicity of HT22 cells and increased expression of H19. Silenced H19 meliorated these adverse impacts of ISO. Interference of H19 exerted neuroprotective roles by repressing modified neurological severity score, inhibiting escape latency, elevating distance and time of target area, and controlling ROS and inflammation. MiR-17-5p might be a promising competing endogenous RNA of H19. The expression of miR-17-5p was reduced in the ISO group and reversed by the absence of H19.

CONCLUSION

Our results of in vitro and in vivo assay indicated that the absence of HT22 is a neuroprotective regulator of cognition and inflammation by accumulating miR-17-5p.

MiR-191-5p alleviates microglial cell injury by targeting Map3k12 (mitogen-activated protein kinase kinase kinase 12) to inhibit the MAPK (mitogen-activated protein kinase) signaling pathway in Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease. Multiple reports have elucidated that microRNAs are promising biomarkers for AD diagnosis and treatment. Herein, the effect of miR-191-5p on microglial cell injury and the underlying mechanism were explored. APP/PS1 transgenic mice were utilized to establish mouse model of AD. Amyloid-β protein 1-42 (Aβ1-42)-treated microglia were applied to establish in vitro cell model of AD. MiR-191-5p expression in hippocampus and microglia was measured by reverse transcription quantitative polymerase chain reaction. The viability and apoptosis of microglia were evaluated by Cell Counting Kit-8 assays and flow cytometry analyses, respectively. The binding relationship between miR-191-5p and its downstream target mitogen-activated protein kinase kinase kinase 12 (Map3k12) was determined by luciferase reporter assays. Pathological degeneration of hippocampus was tested using hematoxylin-eosin staining and Nissl staining. Aβ expression in hippocampus was examined via immunohistochemistry. In this study, miR-191-5p was downregulated in Aβ1-42-stimulated microglia and hippocampal tissues of APP/PS1 mice. MiR-191-5p overexpression facilitated cell viability and inhibited apoptosis rate of Aβ1-42-treated microglia. Mechanically, miR-191-5p targeted Map3k12 3'-untranslated region to downregulate Map3k12 expression. MiR-191-5p inhibited Aβ1-42-induced microglial cell injury and inactivated the MAPK signaling by downregulating Map3k12. Overall, miR-191-5p alleviated Aβ1-42-induced microglia cell injury by targeting Map3k12 to inhibit the MAPK signaling pathway in microglia.

Pan-Tissue Aging Clock Genes That Have Intimate Connections with the Immune System and Age-Related Disease

In our recent transcriptomic meta-analysis, we used random forest machine learning to accurately predict age in human blood, bone, brain, heart, and retina tissues given gene inputs. Although each tissue-specific model utilized a unique number of genes for age prediction, we found that the following six genes were prioritized in all five tissues: CHI3L2, CIDEC, FCGR3A, RPS4Y1, SLC11A1, and VTCN1. Since being selected for age prediction in multiple tissues is unique, we decided to explore these pan-tissue clock genes in greater detail. In the present study, we began by performing over-representation and network topology-based enrichment analyses in the Gene Ontology Biological Process database. These analyses revealed that the immunological terms "response to protozoan," "immune response," and "positive regulation of immune system process" were significantly enriched by these clock inputs. Expression analyses in mouse and human tissues identified that these inputs are frequently upregulated or downregulated with age. A detailed literature search showed that all six genes had noteworthy connections to age-related disease. For example, mice deficient in Cidec are protected against various metabolic defects, while suppressing VTCN1 inhibits age-related cancers in mouse models. Using a large multitissue transcriptomic dataset, we additionally generate a novel, minimalistic aging clock that can predict human age using just these six genes as inputs. Taken all together, these six genes are connected to diverse aspects of aging.