The miR-25802/KLF4/NF-κB signaling axis regulates microglia-mediated neuroinflammation in Alzheimer's disease.

Microglia-mediated neuroinflammation plays a critical role in the occurrence and progression of Alzheimer's disease (AD). In recent years, studies have increasingly explored microRNAs as biomarkers and treatment interventions for AD. This study identified a novel microRNA termed miR-25802 from our high-throughput sequencing dataset of an AD model and explored its role and the underlying mechanism. The results confirmed the miRNA properties of miR-25802 based on bioinformatics and experimental verification. Expression of miR-25802 was increased in the plasma of AD patients and in the hippocampus of APP/PS1 and 5 × FAD mice carrying two and five familial AD gene mutations. Functional studies suggested that overexpression or inhibition of miR-25802 respectively aggravated or ameliorated AD-related pathology, including cognitive disability, Aß deposition, microglial pro-inflammatory phenotype activation, and neuroinflammation, in 5 × FAD mice and homeostatic or LPS/IFN-γ-stimulated EOC20 microglia. Mechanistically, miR-25802 negatively regulates KLF4 by directly binding to KLF4 mRNA, thus stimulating microglia polarization toward the pro-inflammatory M1 phenotype by promoting the NF-κB-mediated inflammatory response. The results also showed that inhibition of miR-25802 increased microglial anti-inflammatory M2 phenotype activity and suppressed NF-κB-mediated inflammatory reactions in the brains of 5 × FAD mice, while overexpression of miR-25802 exacerbated microglial pro-inflammatory M1 activity by enhancing NF-κB pathways. Of note, AD-associated manifestations induced by inhibition or overexpression of miR-25802 via the NF-κB signaling pathway were reversed by KLF4 silencing or upregulation. Collectively, these results provide the first evidence that miR-25802 is a regulator of microglial activity and establish the role of miR-25802/KLF4/NF-κB signaling in microglia-mediated neuroinflammation, suggesting potential therapeutic targets for AD.

Tilianin improves cognition in a vascular dementia rodent model by targeting miR-193b-3p/CaM- and miR-152-3p/CaMKIIα-mediated inflammatory and apoptotic pathways.

Introduction: Although vascular dementia (VaD) is the second most prevalent form of dementia, there is currently a lack of effective treatments. Tilianin, isolated from the traditional drug Dracocephalum moldavica L., may protect against ischemic injury by inhibiting oxidative stress and inflammation via the CaMKII-related pathways but with weak affinity with the CaMKII molecule. microRNAs (miRNAs), functioning in post-transcriptional regulation of gene expression, may play a role in the pathological process of VaD via cognitive impairment, neuroinflammatory response, and neuronal dysfunction. This study aimed to investigate the role of tilianin in VaD therapy and the underlying mechanism through which tilianin regulates CaMKII signaling pathways based on miRNA-associated transcriptional action. Methods: Rats with 2-vessel occlusion (2VO), a standard model of VaD, were treated with tilianin, vehicle control, and target overexpression or downregulation. High-throughput sequencing, qRT-PCR, and western blot analyses were utilized to identify the downstream target genes and signaling pathways of tilianin involved in VaD. Results: Our results showed that tilianin ameliorated cognitive deficits, neurodegeneration, and microglial and astrocytic activation in rats with 2VO. Subsequent high-throughput sequencing and qRT-PCR analyses revealed that tilianin increased the downregulated miR-193b-3p and miR-152-3p levels in the cortex and hippocampus of 2VO rats. Mechanistically, miR-193b-3p targeting CaM and miR-152-3p targeting CaMKIIα were identified to play a role in VaD-associated pathology, inhibiting the p38 MAPK/NF--κB p65 pathway and decreasing TNF-α and IL-6 levels. Further gain- and loss-of-function experiments for these key genes showed that tilianin-exerted cognitive improvement by activating the p38 MAPK/NF--κB p65 and Bcl-2/Bax/caspase-3/PARP pathways in the brain of 2VO rats was abolished by miR-193b-3p and miR-152-3p inhibition. Moreover, CaM and CaMKIIα overexpression eliminated the elevated effects of miR-193b-3p and miR-152-3p on tilianin's protection against ischemic injury through increased inflammatory reactions and apoptotic signaling. Discussion: Together, these findings indicate that tilianin improves cognition by regulating the miR-193b-3p/CaM- and miR-152-3p/CaMKIIα-mediated inflammatory and apoptotic pathways, suggesting a potential small-molecule regulator of miRNA associated with inflammatory signaling for VaD treatment.

Role of traditional Chinese medicine in ameliorating mitochondrial dysfunction via non-coding RNA signaling: Implication in the treatment of neurodegenerative diseases.

Neurodegenerative diseases (NDs) are common chronic disorders associated with progressive nervous system damage, including Alzheimer's disease, Parkinson's disease, and Huntington's disease, among others. Mitochondria are abundant in various nervous system cells and provide a bulk supply of the adenosine triphosphate necessary for brain function, considered the center of the free-radical theory of aging. One common feature of NDs is mitochondrial dysfunction, which is involved in many physiopathological processes, including apoptosis, inflammation, oxidative stress, and calcium homeostasis. Recently, genetic studies revealed extensive links between mitochondrion impairment and dysregulation of non-coding RNAs (ncRNAs) in the pathology of NDs. Traditional Chinese medicines (TCMs) have been used for thousands of years in treating NDs. Numerous modern pharmacological studies have demonstrated the therapeutic effects of prescription, herbal medicine, bioactive ingredients, and monomer compounds of TCMs, which are important for managing the symptoms of NDs. Some highly effective TCMs exert protective effects on various key pathological features regulated by mitochondria and play a pivotal role in recovering disrupted signaling pathways. These disrupted signaling pathways are induced by abnormally-expressed ncRNAs associated with mitochondrial dysfunction, including microRNAs, long ncRNAs, and circular RNAs. In this review, we first explored the underlying ncRNA mechanisms linking mitochondrial dysfunction and neurodegeneration, demonstrating the implication of ncRNA-induced mitochondrial dysfunction in the pathogenesis of NDs. The ncRNA-induced mitochondrial dysfunctions affect mitochondrial biogenesis, dynamics, autophagy, Ca2+ homeostasis, oxidative stress, and downstream apoptosis. The review also discussed the targeting of the disease-related mitochondrial proteins in NDs and the protective effects of TCM formulas with definite composition, standardized extracts from individual TCMs, and monomeric compounds isolated from TCM. Additionally, we explored the ncRNA regulation of mitochondrial dysfunction in NDs and the effects and potential mechanisms of representative TCMs in alleviating mitochondrial pathogenesis and conferring anti-inflammatory, antioxidant, and anti-apoptotic pathways against NDs. Therefore, this review presents an overview of the role of mitochondrion-related ncRNAs and the target genes for TCM-based therapeutic interventions in NDs, providing insight into understanding the "multi-level compound-target-pathway regulatory" treatment mechanism of TCMs.

Comprehensive analysis of dysregulated circular RNAs and construction of a ceRNA network involved in the pathology of Alzheimer's disease in a 5 × FAD mouse model.

Introduction: Alzheimer's disease (AD) causes a decline in cognitive function that poses a significant hazard to human health. However, the exact pathogenesis of AD and effective treatment have both proven elusive. Circular RNAs (circRNAs), which were initially deemed as meaningless non-coding RNAs, have been shown to participate in a variety of physiological and pathological processes. However, the variations and characteristics of circRNAs are not fairly well understood during the occurrence and development of AD. Methods: In this study, we performed RNA sequencing analyses, identified circRNA expression profiles, and explored the circRNA-associated competing endogenous RNA (ceRNA) relationship in the hippocampus of five familial AD (5 × FAD) mice with cognitive dysfunction. Results: The RNA sequencing results identified 34 dysregulated circRNAs in the hippocampus of 5 × FAD mice, including 17 upregulated and 17 downregulated circRNAs. The circRNA-miRNA interaction network for the dysregulated circRNAs was generated, and it was found to include 34 circRNAs and 711 miRNAs. Next, 2067 mRNAs potentially modulated by upregulated circRNA-interacting miRNAs and 2297 mRNAs potentially modulated by downregulated circRNA-interacting miRNAs were identified. Pathway enrichment analyses revealed that the circRNA-miRNA-mRNA network modulated AD development via multiple pathways, such as axon guidance, mitogen-activated protein kinase, and neurotrophin. The associated biological processes were mainly related to neuron projection development, cell morphogenesis, and head development. Their corresponding distributions were especially high in the axon, postsynapse, and neuronal body. We constructed a ceRNA network that included five circRNAs, four miRNAs, and 188 mRNAs. In this network, the differential expressions of three circRNAs (circRNA04655, circRNA00723, and circRNA01891), two miRNAs (miR-3470b and miR-6240), and 13 mRNAs (Vgll3, Nhsl2, Rab7, Tardbp, Vps33b, Fam107a, Tacr1, Ankrd40, Creb1, Snap23, Csnk1a1, Bmi1, and Bfar) in the hippocampus of 5 × FAD mice using qRT-PCR analyses were consistent with the RNA sequencing results. Another one circRNAs (circRNA00747) and two mRNAs (Zfp37 and Polr1e) had similar expression trends to the sequencing data, while circRNA03723 and Mapk10 had deviated expression trends to the sequencing data. Conclusions: In conclusion, our study uncovered dysregulated circRNA expression profiles in the hippocampus of 5 × FAD mice, stretched comprehension of ceRNA biology, investigated the potential role of this ceRNA network in pathogenesis and progression, and identified potential biomarkers and therapeutic targets for AD.

RNA sequencing-based identification of the regulatory mechanism of microRNAs, transcription factors, and corresponding target genes involved in vascular dementia.

Vascular dementia (VaD) is the second most common form of dementia with uncertain mechanisms and no effective treatments. microRNAs (miRNAs) and transcription factors (TFs) are considered regulatory factors of genes involved in many diseases. Therefore, this work investigated the aberrantly expressed miRNAs, TFs, corresponding target genes, and their co-regulatory networks in the cortex of rats with bilateral common carotid artery occlusion (2VO) to uncover the potential mechanism and biomarkers of VaD. Differentially expressed genes (DEGs), miRNAs (DEMs), and TFs (DETFs) were identified using RNA sequencing, and their interaction networks were constructed using Cytoscape. The results showed that rats with 2VO had declined cognitive abilities and neuronal loss in the cortex than sham rats. DEGs, DEMs, and DETFs were discriminated between rats with 2VO and sham rats in the cortex, as shown by the 13 aberrantly expressed miRNAs, 805 mRNAs, and 63 TFs. The miRNA-TF-target gene network was constructed, showing 523 nodes and 7237 edges. Five miRNAs (miR-5132-5p, miR-764-3p, miR-223-3p, miR-145-5p, and miR-122-5p), ten TFs (Mxi1, Nfatc4, Rxrg, Zfp523, Foxj2, Nkx6-1, Klf4, Klf5, Csrnp1, and Prdm6), and seven target genes (Serpine1, Nedd4l, Pxn, Col1a1, Plec, Trip12, and Tpm1) were chosen as the significant nodes to construct feed-forward loops (FFLs). Gene Ontology and pathway enrichment analysis revealed that these miRNA and TF-associated genes are mostly involved in the PI3K/Akt, neuroactive ligand-receptor interaction, calcium signaling, and Wnt signaling pathways, along with central locations around the cell membrane. They exert functions such as growth factor binding, integrin binding, and extracellular matrix structural constituent, with representative biological processes like vasculature development, cell-substrate adhesion, cellular response to growth factor stimulus, and synaptic transmission. Furthermore, the expression of three miRNAs (miR-145-5p, miR-122-5p, and miR-5132-5p), six TFs (Csrnp1, Klf4, Nfatc4, Rxrg, Foxj2, and Klf5), and five mRNAs (Serpine1, Plec, Nedd4l, Trip12, and Tpm1) were significantly changed in rats with VaD, in line with the outcome of RNA sequencing. In the potential FFL, miR-145-5p directly bound Csrnp1 and decreased its mRNA expression. These results might help the understanding of the underlying regulatory mechanisms of miRNA-TF-genes, providing potential therapeutic targets in VaD.

The Relationship between the Aberrant Long Non-Coding RNA-Mediated Competitive Endogenous RNA Network and Alzheimer's Disease Pathogenesis.

Alzheimer's disease (AD) is a common neurodegenerative disorder characterized by cognitive dysfunction. The role of long non-coding RNAs (lncRNAs) with the action of competitive endogenous RNA (ceRNA) in AD remains unclear. The present study aimed to identify significantly differentially expressed lncRNAs (SDELs) and establish lncRNA-associated ceRNA networks via RNA sequencing analysis and a quantitative real-time Polymerase Chain Reaction (qPCR) assay using transgenic mice with five familial AD mutations. A total of 53 SDELs in the cortex and 51 SDELs in the hippocampus were identified, including seven core SDELs common to both regions. The functions and pathways were then investigated through the potential target genes of SDELs via Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses, which indicate biological effects, action distributions, and pathological transductions associated with AD. Based on the ceRNA hypothesis, integrated ceRNA networks in the cortex and hippocampus of lncRNA-miRNA-mRNA were constructed. The core SDEL-mediated ceRNA relationship was established and the expression of these RNAs was verified by qPCR. The results identified lncRNA ENSMUST00000127786 and highlighted miRNAs and mRNAs as potential key mediators in AD. These findings provide AD-derived lncRNA-mediated ceRNA profiles, and further experimental evidence is needed to confirm these identified ceRNA regulatory relationships.

Exploration of the Molecular Mechanisms of Hyssopus cuspidatus Boriss Treatment of Asthma in an mRNA-miRNA Network via Bioinformatics Analysis.

Hyssopus cuspidatus Boriss (H. cuspidatus) is a traditional Chinese medicine commonly used in the treatment of asthma. In the present study, we applied bioinformatics techniques for mRNA-miRNA profiling to elucidate the potential mechanisms of H. cuspidatus in asthma treatment. Bioactive compounds from H. cuspidatus, potential therapeutic targets of H. cuspidatus, and asthma-related targets were identified from the literature and databases. The intersection of H. cuspidatus-related targets and asthma-related targets was identified using the STRING platform. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed using the Metascape platform. Networks were constructed from these nodes using Cytoscape. The results showed that 23 active compounds were identified in H. cuspidatus, sharing 122 common asthma-related targets. Moreover, 43 miRNAs regulating 19 key targets involved in the antiasthmatic effects of H. cuspidatus were identified. Further analysis of biological pathways, active compound-key target-pathway network, and active compound-key target-miRNA network indicated that the antiasthmatic effects of H. cuspidatus mainly occurred through caffeic acid, methyl rosmarinate, luteolin, esculetin, and 8-hydroxycirsimaritin. These compounds interacted with multiple miRNAs, including miR-99a, miR-498, miR-33b, and miR-18a, regulating multiple genes, including JAK, STAT3, EGFR, LYN, and IL-6, in multiple pathways, including those involved in the regulation of JAK-STAT signaling, EGFR tyrosine kinase inhibitor resistance, PI3K-Akt signaling, and inflammation. In summary, we have elucidated the potential mechanisms of H. cuspidatus treatment of asthma from a systemic and holistic perspective through analysis of compound-mRNA-miRNA interaction. Our study should provide new insights for further research on H. cuspidatus treatment of asthma.

miR-23b-3p rescues cognition in Alzheimer's disease by reducing tau phosphorylation and apoptosis via GSK-3ß signaling pathways.

Dysregulated microRNA (miRNA) expression in the brain can contribute to cognitive dysfunction and aberrant tau hyperphosphorylation in Alzheimer's disease (AD). Several studies have reported a role for microRNA-23b-3p (miR-23b-3p) in various neurologic disorders; however, its involvement in cognition-related functions remains unclear. In the present study, we investigated the potential therapeutic effects and mechanisms of miR-23b-3p in AD. miRNA profiles in the cortex of amyloid precursor protein (APP)/presenilin 1 (PS1) double transgenic mice (APP/PS1 mice) demonstrated that miR-23b-3p was reduced. This decrease was verified in APPswe cells, SAMP8 mouse brains, and plasma from AD patients. Furthermore, glycogen synthase kinase-3ß (GSK-3ß), a major tau kinase implicated in tau pathology, was identified as a target of miR-23b-3p. Functional in vivo studies demonstrated that intracerebroventricular delivery of miR-23b-3p in APP/PS1 mice ameliorated cognitive deficits, histopathological changes, and tau phosphorylation immunoreactivity at several sites by inhibiting GSK-3ß expression and activation. Similarly, the upregulation of miR-23b-3p in APPswe cells inhibited GSK-3ß-mediated tau hyperphosphorylation, Aß1-42 generation, and neuronal apoptosis, resulting in the suppression of the GSK-3ß/p-tau and Bax/caspase-3 pathways. Collectively, our findings strongly support the hypothesis that miR-23b-3p plays a neuroprotective role in AD, thereby identifying miR-23b-3p as a promising therapeutic target for AD.

miR-30a-5p induces Aß production via inhibiting the nonamyloidogenic pathway in Alzheimer's disease.

Alzheimer's disease (AD) pathogenesis is known to involve a dysregulation of microRNA expression, and these intricate transcriptional cascades between multiple pathological manifestations affect brain homeostasis. Previous studies have revealed that miR-30a-5p participates in neuronal damage and is upregulated in amyloid beta-peptide (Aß)-induced models. However, its involvement in cognition dysfunction and the AD pathogenic process remains unclear. In the present study, we investigated the mechanisms underlying miR-30a-5p involvement in AD, and its potential as a therapeutic target. Our results reveal that miR-30a-5p was substantially upregulated during the pathological progression of AD, presenting as an increased level in the cortex and hippocampus of APP/PS1 and five familial AD mice, AD cells, and the plasma of AD patients. miR-30a-5p overexpression also induced neuronal injury and apoptosis in AD cells. Mechanistically, miR-30a-5p negatively regulated ADAM10 and SIRT1 by directly binding to their 3'-untranslated regions. A possible association between SIRT1 and ADAM10 was observed via their rescue of miR-30a-5p-induced RARß downregulation. Interestingly, miR-30a-5p was observed to inhibit the nonamyloidogenic pathway by down regulating ADAM10 and SIRT1, thus promoting Aß1-42 overproduction. In APP/PS1 mice, knockdown of miR-30a-5p ameliorated cognitive dysfunctions and neurodegenerative changes, suppressed Aß accumulation, and inhibited Aß1-42 generation by enhancing the nonamyloidogenic pathway via upregulation of ADAM10 and SIRT1. However, these improvements were blocked by ADAM10 and SIRT1 silencing. In conclusion, the present study implicates dysregulation of the miR-30a-5p/ ADAM10/ SIRT1 pathway as a critical mediator of AD pathogenesis, highlighting the importance of epigenetics and identifying novel therapeutic targets in the nonamyloidogenic pathway.