Vascular dementia (VaD) is a common cause of cognitive decline and dementia of vascular origin, but the precise pathological mechanisms are unknown, and so effective clinical treatments have not been established. Tilianin, the principal active compound of total flavonoid extract from Dracocephalum moldavica L., is a candidate therapy for cardio-cerebrovascular diseases in China. However, its potential in the treatment of VaD is unclear. The present study is aimed at investigating the protective effects of tilianin on VaD and exploring the underlying mechanism of the action. A model of VaD was established by permanent 2-vessel occlusion (2VO) in rats. Human neurons (hNCs) differentiated from human-induced pluripotent stem cells were used to establish an oxygen-glucose deprivation (OGD) model. The therapeutic effects and potential mechanisms of tilianin were identified using behavioral tests, histochemistry, and multiple molecular biology techniques such as Western blot analysis and gene silencing. The results demonstrated that tilianin modified spatial cognitive impairment, neurodegeneration, oxidation, and apoptosis in rats with VaD and protected hNCs against OGD by increasing cell viability and decreasing apoptosis rates. A study of the mechanism indicated that tilianin restored p-CaMKII/ERK1/2/CREB signaling in the hippocampus, maintaining hippocampus-independent memory. In addition, tilianin inhibited an ox-CaMKII/p38 MAPK/JNK/NF-κB associated inflammatory response caused by cerebral oxidative stress imbalance in rats with VaD. Furthermore, specific CaMKIIα siRNA action revealed that tilianin-exerted neuroprotection involved increase of neuronal viability, inhibition of apoptosis, and suppression of inflammation, which was dependent on CaMKIIα. In conclusion, the results suggested the neuroprotective effect of tilianin in VaD and the potential mechanism associated with dysfunction in the regulation of p-CaMKII-mediated long-term memory and oxidation and inflammation involved with ox-CaMKII, which may lay the foundation for clinical trials of tilianin for the treatment of VaD in the future.

Existing studies have revealed that microRNAs (miRNAs) have a role in cognitive deficits in Alzheimer’s disease (AD). However, the function and pathophysiological mechanism of deregulated miRNAs underlying AD pathology remain to be investigated. The present study aimed to clarify the role and mechanism of miR-148a-3p in AD. RNA sequencing, qRT-PCR, and western blot analysis were used to identify the aberrant expression and signaling of miR-148a-3p within cells, mice, and patients with AD. Molecular biology techniques involving luciferase reporter assays, gene overexpression and silencing, chromatin immunoprecipitation, and adeno-associated virus-based miRNA overexpression were used to explore the biological function and mechanisms of miR-148a-3p. Downregulation of miR-148a-3p was identified in AD. Upregulation of miR-148a-3p was found to protect neuronal cells against Aβ-associated tau hyperphosphorylation by directly targeting p35/CDK5 and PTEN/p38 mitogen-activated protein kinase (MAPK) pathways. A mutual regulatory link between miR-148a-3p and PTEN using a feedforward arrangement was confirmed via promotion of transcription and expression of miR-148a-3p by way of the PTEN/Akt/CREB pathway. Significantly, in vivo targeting of miR-148a-3p signaling ameliorated cognitive deficits by decreasing p35/PTEN-elicited tau hyperphosphorylation, accompanied by feedforward transduction of the PTEN/Akt/CREB pathway. In conclusion, the present study implicated the miR-148a-3p/p35/PTEN pathway as an essential contributor to tau hyperphosphorylation and feedforward regulation in AD.

No abstract

Vascular dementia (VaD) is a general term used to describe difficulties in memory, reasoning, judgment, and planning caused by a reduced blood flow to the brain and consequent brain damage, in which microRNAs (miRNAs) are involved. Dracocephalum moldavica L. (D. moldavica) is traditionally used in the treatment of cardiovascular diseases as well as VaD, but the biomolecular mechanisms underlying its therapeutic effect are obscure. In the present study, the molecular mechanisms involved in the treatment of VaD by the total flavonoids from Dracocephalum moldavica L. (TFDM) were explored by the identification of miRNA profiling using bioinformatics analysis and experimental verification. A total of 2,562 differentially expressed miRNAs (DEMs) and 3,522 differentially expressed genes (DEGs) were obtained from the GSE120584 and GSE122063 datasets, in which the gene functional enrichment and protein-protein interaction network of 93 core targets, originated from the intersection of the top DEM target genes and DEGs, were established for VaD gene profiling. One hundred and eighty-five targets interacting with 42 flavonoids in the TFDM were included in a compound-target network, subsequently found that they overlapped with potential targets for VaD. These 43 targets could be considered in the treatment of VaD by TFDM, and included CaMKII, MAPK, MAPT, PI3K, and KDR, closely associated with the vascular protective effect of TFDM, as well as anti-oxidative, anti-inflammatory, and anti-apoptotic properties. The subsequent analysis of the compound-target gene-miRNA network indicated that eight miRNAs that mediated 43 targets had a close interaction with TFDM, suggesting that the neuroprotective effects were principally due to kaempferol, apigenin, luteolin, and quercetin, which were mostly associated with the miR-3184-3p/ESR1, miR-6762-3p/CDK1, miR-6777-3p/ESRRA, and other related axes. Furthermore, the in vitro oxygen-glucose deprivation (OGD) model demonstrated that the dysregulation of miR-3184-3p and miR-6875-5p found by qRT-PCR was consistent with the changes in the bioinformatics analysis. TFDM and its active compounds involving tilianin, luteolin, and apigenin showed significant effects on the upregulation of miR-3184-3p and downregulation of miR-6875-5p in OGD-injured cells, in line with the improved cell viability. In conclusion, our findings revealed the underlying miRNA-target gene network and potential targets of TFDM in the treatment of VaD.

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.