Knockdown of lncRNA PCAI protects against cognitive decline induced by hippocampal neuroinflammation via regulating SUZ12

Dexmedetomidine attenuates the neuroinflammation and cognitive dysfunction in aged mice by targeting the SNHG14/miR‑340/NF‑κB axis

Neuroinflammation plays a key role in the pathogenesis of postoperative cognitive dysfunction (POCD). Results of our previous study demonstrated that dexmedetomidine (Dex) attenuates neuroinflammation in BV2 cells treated with lipopolysaccharide (LPS) by targeting the microRNA (miR)-340/NF-κB axis. However, the molecular mechanisms by which Dex improves POCD remain unclear. In the present study, the association between long non-coding (lnc)RNA small nucleolar RNA host gene 14 (SNHG14) and miR-340 in BV2 microglial cells was determined using a dual-luciferase reporter assay. In addition, SNHG14, miR-340 and NF-κB expression levels were measured in LPS-treated BV-2 cells and hippocampal tissues of mice with POCD, and an enzyme-linked immunosorbent assay was used to determine the levels of proinflammatory mediators. Results of the present study demonstrated that SNHG14 exhibited potential as a target of miR-340. In addition, SNHG14 knockdown increased the levels of miR-340 and reduced the levels of NF-κB in LPS-treated BV2 cells. In addition, Dex treatment significantly reduced the levels of SNHG14 and NF-κB, and elevated the levels of miR-340 in the hippocampus of aged mice with POCD. Moreover, Dex treatment notably decreased the expression levels of TNF-α, IL-1β, IL-2, IL-6, IL-8 and IL-12 in the hippocampus of aged mice with POCD by upregulating miR-340. The spatial memory impairments in aged mice with POCD were also notably increased following Dex treatment via upregulation of miR-340. Collectively, results of the present study demonstrated that Dex may protect microglia from LPS-induced neuroinflammation in vitro and attenuate hippocampal neuroinflammation in aged mice with POCD in vivo via the SNHG14/miR-340/NF-κB axis. The present study may provide further insights into the mechanisms underlying Dex in the treatment of POCD.

Neuroepigenetics of ageing and neurodegeneration-associated dementia: An updated review

Gene expression is tremendously altered in the brain during memory acquisition, recall, and forgetfulness. However, non-genetic factors, including environmental elements, epigenetic changes, and lifestyle, have grabbed significant attention in recent years regarding the etiology of neurodegenerative diseases (NDD) and age-associated dementia. Epigenetic modifications are essential in regulating gene expression in all living organisms in a DNA sequence-independent manner. The genes implicated in ageing and NDD-related memory disorders are epigenetically regulated by processes such as DNA methylation, histone acetylation as well as messenger RNA editing machinery. The physiological and optimal state of the epigenome, especially within the CNS of humans, plays an intricate role in helping us adjust to the changing environment, and alterations in it cause many brain disorders, but the mechanisms behind it still need to be well understood. When fully understood, these epigenetic landscapes could act as vital targets for pharmacogenetic rescue strategies for treating several diseases, including neurodegeneration- and age-induced dementia. Keeping this objective in mind, this updated review summarises the epigenetic changes associated with age and neurodegeneration-associated dementia.

Bioinformatics Analysis of Next Generation Sequencing Data Identifies Molecular Biomarkers Associated With Type 2 Diabetes Mellitus

Background

Type 2 diabetes mellitus (T2DM) is the most common metabolic disorder. The aim of the present investigation was to identify gene signature specific to T2DM.

Methods

The next generation sequencing (NGS) dataset GSE81608 was retrieved from the gene expression omnibus (GEO) database and analyzed to identify the differentially expressed genes (DEGs) between T2DM and normal controls. Then, Gene Ontology (GO) and pathway enrichment analysis, protein-protein interaction (PPI) network, modules, miRNA (micro RNA)-hub gene regulatory network construction and TF (transcription factor)-hub gene regulatory network construction, and topological analysis were performed. Receiver operating characteristic curve (ROC) analysis was also performed to verify the prognostic value of hub genes.

Results

A total of 927 DEGs (461 were up regulated and 466 down regulated genes) were identified in T2DM. GO and REACTOME results showed that DEGs mainly enriched in protein metabolic process, establishment of localization, metabolism of proteins, and metabolism. The top centrality hub genes APP, MYH9, TCTN2, USP7, SYNPO, GRB2, HSP90AB1, UBC, HSPA5, and SQSTM1 were screened out as the critical genes. ROC analysis provides prognostic value of hub genes.

Conclusion

The potential crucial genes, especially APP, MYH9, TCTN2, USP7, SYNPO, GRB2, HSP90AB1, UBC, HSPA5, and SQSTM1, might be linked with risk of T2DM. Our study provided novel insights of T2DM into genetics, molecular pathogenesis, and novel therapeutic targets.

Effects of LncRNA GAS5/miR-137 general anesthesia on cognitive function by TCF4 inflammatory bodies in patients undergoing lumbar spinal canal decompression

Lumbar spinal stenosis is a common orthopedic disease in clinical practice at present. Postoperative cognitive dysfunction (POCD) refers to the phenomenon of impaired memory. However, whether long noncoding RNA (LncRNA) GAS5 contributes to the mechanism of cognitive function in undergoing lumbar spinal canal decompression remains unknown. Thus, the present study investigated the precise details of LncRNA GAS5 involvement in Postoperative cognitive dysfunction of patients undergoing lumbar spinal canal decompression. Patients undergoing lumbar spinal canal decompression with cognitive function and Normal healthy volunteers were obtained. C57BL/6 mice were maintained with a 2% concentration of sevoflurane in 100% oxygen at a flow rate of 2 L minute-1 for 4 hours. LncRNA GAS5 gene expression were up-regulated in patients undergoing lumbar spinal canal decompression. In mice model, LncRNA GAS5 gene expression also increased. LncRNA GAS5 promoted neuroinflammation in vitro model. LncRNA GAS5 raised cognitive impairment and increased neuroinflammation in mice model. LncRNA GAS5 suppressed miR-137 in vitro model. MiR-137 reduced neuroinflammation in vitro model. MiR-137 suppressed TCF4 protein expression in vitro model. Transcription factor TCF4 activates the expression of bHLH. Taking together, this experiment provide the first experimental and clinical evidence that LncRNA GAS5/miR-137 promoted anesthesia-induced cognitive function to increase inflammatory bodies in patients undergoing lumbar spinal canal decompression, suggesting it may be a biomarker of POCD and a potential therapeutic target for POCD.

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.

A putative role for lncRNAs in epigenetic regulation of memory

The central dogma of molecular genetics is defined as encoded genetic information within DNA, transcribed into messenger RNA, which contain the instructions for protein synthesis, thus imparting cellular functionality and ultimately life. This molecular genetic theory has given birth to the field of neuroepigenetics, and it is now well established that epigenetic regulation of gene transcription is critical to the learning and memory process. In this review, we address a potential role for a relatively new player in the field of epigenetic crosstalk - long non-coding RNAs (lncRNAs). First, we briefly summarize epigenetic mechanisms in memory formation and examine what little is known about the emerging role of lncRNAs during this process. We then focus discussions on how lncRNAs interact with epigenetic mechanisms to control transcriptional programs under various conditions in the brain, and how this may be applied to regulation of gene expression necessary for memory formation. Next, we explore how epigenetic crosstalk in turn serves to regulate expression of various individual lncRNAs themselves. To highlight the importance of further exploring the role of lncRNA in epigenetic regulation of gene expression, we consider the significant relationship between lncRNA dysregulation and declining memory reserve with aging, Alzheimer's disease, and epilepsy, as well as the promise of novel therapeutic interventions. Finally, we conclude with a discussion of the critical questions that remain to be answered regarding a role for lncRNA in memory.

Different Anesthetic Drugs Mediate Changes in Neuroplasticity During Cognitive Impairment in Sleep-Deprived Rats via Different Factors

Background

Perioperative neuro-cognitive disorders (PND) are preoperative and postoperative complications of multiple nervous systems, typically manifested as decreased memory and learning ability after surgery. It was used to replace the original definition of postoperative cognitive dysfunctions (POCD) from 2018. Our previous studies have shown that sevoflurane inhalation can lead to cognitive dysfunction in Sprague-Dawley rats, but the specific mechanism is still unclear.

Material/Methods

Thirty-six male Sprague-Dawley rats were randomly divided into 6 groups (n=6): the SD group was given 24-h acute sleep deprivation; Sevoflurane was inhaled for 2 h in the Sevo group. Two mL propofol was injected into the tail vein of rats in the Prop group. The rats in the SD+Sevo group and SD+Prop group were deprived of sleep before intervention in the same way as before.

Results

We noted significant behavioral changes in rats treated with SIK3 inhibitors or tau phosphorylation agonists before propofol injection or sevoflurane inhalation, with associated protein levels and dendritic spine density documented. Sevoflurane anesthesia-induced cognitive impairment following acute sleep deprivation was more pronounced than sleep deprivation-induced cognitive impairment alone and resulted in increased brain SIK3 levels, increased phosphorylation of total tau and tau, and decreased acetylation modifications. After using propofol, the cognitive function returned to baseline levels with a series of reversals of cognitive dysfunction.

Conclusions

These results suggest that sevoflurane inhalation via the SIK3 pathway aggravates cognitive impairment after acute sleep deprivation and that propofol anesthesia reverses the effects of sleep deprivation by affecting modifications of tau protein.

LncRNA NONMMUT055714 acts as the sponge of microRNA-7684-5p to protect against postoperative cognitive dysfunction

Postoperative cognitive dysfunction (POCD) is a neurological complication of surgery especially common in elderly patients. In this study, we investigated the role of NONMMUT055714 in POCD via regulation of miR-7684-5p. In a POCD mouse model, we induced overexpression of NONMUTT055714 via transfection of lentivrus into the hippocampus, and used the Morris water maze for assessment of cognitive function. Silencing of NONMUTT055714 and miR-7684-5p was induced in primary hippocampal neurons to observe the effects of these regulatory RNAs on cellular processes. Bioinformatics analysis and a double luciferase reporter experiment were performed to further explore the relationship between NONMMUT055714, miR-7684-5p, and SORLA. Cell and animal rescue experiments were performed to verify the ability of miR-7684-5p to reverse the protective effects of NONMMUT055714 overexpression in POCD. We observed that NONMMUT055714 has decreased expression in the POCD mouse model. Overexpression of NONMMUT055714 protected against cognitive impairment of the POCD mouse model in vivo. We identified miR-7684-5p as a NONMMUT055714-related miRNA and in turn as an upstream regulator of SORLA. We found that NONMMUT055714 downregulation is associated with decreased SORLA, increased Aβ and p-tau expression, increased inflammatory biomarkers, increased markers of oxidative stress, and increased neuronal apoptosis in vitro. The effects of NONMMUT055714 downregulation were reversed by silencing miR-7684-5p in vitro and in vivo. Taken together, our findings suggest that NONMMUT055714 is protective against the development of POCD via its function as a ceRNA (or miRNA sponge) in the regulation of miR-7684-5p and SORLA. We therefore propose NONMMUT055714 as a novel target for the investigation and prevention of POCD.

LncRNA Rian ameliorates sevoflurane anesthesia-induced cognitive dysfunction through regulation of miR-143-3p/LIMK1 axis

Sevoflurane could stimulate neurotoxicity and result in postoperative cognitive dysfunction (POCD). Long non-coding RNAs (lncRNAs) have been implicated in the regulation of nervous system disease. This study was performed to investigate role and mechanism of lncRNA Rian (RNA imprinted and accumulated in nucleus) in sevoflurane anesthesia-induced cognitive dysfunction. Mice post-sevoflurane anesthesia showed cognitive impairments and neuronal damage and apoptosis. However, intracerebroventricularly injection with Adenovirus (Ad) for the over-expression of Rian ameliorated sevoflurane-induced neuronal damage and apoptosis. Cognitive impairments induced by sevoflurane were attenuated by injection with Ad-Rian. Moreover, transfection with Ad-Rian also protected isolated primary hippocampal neurons against sevoflurane-induced decrease of cell viability and increase of lactic acid dehydrogenase (LDH) and apoptosis. Mechanistically, Rian bind to miR-143-3p, and decreased expression of LIMK1 (Lim kinase 1) through negative regulation of miR-143-3p. Knockdown of LIMK1 aggravated sevoflurane-induced decrease of cell viability and increase of LDH and apoptosis in neurons, while over-expression attenuated LIMK1 silence-induced neuronal damage post-sevoflurane anesthesia. In conclusion, Rian demonstrated neuroprotective effects against sevoflurane anesthesia-induced cognitive dysfunction through regulation of miR-143-3p/LIMK1 axis, providing promising target for sevoflurane anesthesia-induced cognitive dysfunction.

The Expanding Regulatory Mechanisms and Cellular Functions of Long Non-coding RNAs (lncRNAs) in Neuroinflammation

LncRNAs have emerged as important regulatory molecules in biological processes. They serve as regulators of gene expression pathways through interactions with proteins, RNA, and DNA. LncRNA expression is altered in several diseases of the central nervous system (CNS), such as neurodegenerative disorders, stroke, trauma, and infection. More recently, it has become clear that lncRNAs contribute to regulating both pro-inflammatory and anti-inflammatory pathways in the CNS. In this review, we discuss the molecular pathways involved in the expression of lncRNAs, their role and mechanism of action during gene regulation, cellular functions, and use of lncRNAs as therapeutic targets during neuroinflammation in CNS disorders.

LncRNA AK148321 alleviates neuroinflammation in LPS-stimulated BV2 microglial cell through regulating microRNA-1199-5p/HSPA5 axis

AIMS

Dysregulated long non-coding RNA (lncRNA) expression is closely related to neuroinflammation, leading to multiple neurodegenerative diseases. In this study, we investigated the function and regulation of lncRNA AK148321 in neuroinflammation using an in vitro lipopolysaccharide (LPS)-stimulated BV2 microglial cell system.

METHODS

Expression of AK148321 was analyzed by qPCR. Inflammatory cytokine expression levels were determined by ELISA assay. The interaction between AK148321, microRNA (miRNA), and its target gene was validated by luciferase reporter assay and RNA immunoprecipitation (RIP). Cell apoptosis was analyzed by Annexin V/PI staining.

RESULTS

LPS treatment suppressed AK148321 expression in BV2 cells. Overexpression of AK148321 inhibited LPS-induced BV2 microglial cell activation and decreased the expression of inflammatory cytokine TNF-α and IL-1β. AK148321 function as a competing endogenous RNA (ceRNA) by sponging microRNA-1199-5p (MiR-1199-5p). In LPS-stimulated BV2 cells, AK148321 exerted its inhibitory function via negatively modulating miR-1199-5p expression. Moreover, we identified that Heat Shock Protein Family A Member 5 (HSPA5) was a direct target of miR-1199-5p. RIP assay using the anti-Ago2 antibody further validated the relationship among AK148321, miR-1199-5p and HSPA5. The AK148321/miR-1199-5p/HSPA5 axis regulated the neuroinflammation in LPS-induced BV2 microglial cells. Microglial cell culture supernatant from LPS-stimulated, AK148321-overexpressing BV2 cells suppressed the cell apoptosis of mouse hippocampal neuronal cell HT22, while HSPA5 knockdown abrogated the suppression effect.

CONCLUSION

Our findings suggest that AK148321 alleviates neuroinflammation in LPS-stimulated BV2 microglial cells through miR-1199-5p/HSPA5 axis.