Circulating Small Extracellular Vesicle-Derived miR-342-5p Ameliorates Beta-Amyloid Formation via Targeting Beta-site APP Cleaving Enzyme 1 in Alzheimer's Disease.

Alzheimer's disease (AD) is a common neurodegenerative disorder with progressive cognitive impairment in the elderly. Beta-amyloid (Aß) formation and its accumulation in the brain constitute one of the pathological hallmarks of AD. Until now, how to modulate Aß formation in hippocampal neurons remains a big challenge. Herein, we investigated whether the exosomal transfer of microRNA (miR) relates to amyloid pathology in the recipient neuron cells. We isolated circulating small extracellular vesicles (sEVs) from AD patients and healthy controls, determined the miR-342-5p level in the sEVs by RT-PCR, and evaluated its diagnostic performance in AD. Then, we took advantage of biomolecular assays to estimate the role of miR-342-5p in modulating the amyloid pathway, including amyloid precursor protein (APP), beta-site APP cleaving enzyme 1 (BACE1), and Aß42. Furthermore, we subjected HT22 cells to the sEVs from the hippocampal tissues of transgenic APP mice (Exo-APP) or C57BL/6 littermates (Exo-CTL), and the Exo-APP enriched with miR-342-5p mimics or the control to assess the effect of the sEVs' delivery of miR-342-5p on Aß formation. We observed a lower level of miR-342-5p in the circulating sEVs from AD patients compared with healthy controls. MiR-342-5p participated in Aß formation by modulating BACE1 expression, specifically binding its 3'-untranslated region (UTR) sequence. Exo-APP distinctly promoted Aß42 formation in the recipient cells compared to Exo-CTL. Intriguingly, miR-342-5p enrichment in Exo-APP ameliorated amyloid pathology in the recipient cells. Our study indicated that miR-342-5p was dysregulated in human circulating sEVs from AD patients; sEV transfer of miR-342-5p ameliorates Aß formation by modulating BACE1 expression. These findings highlight the promising potential of exosomal miRNAs in AD clinical therapy.

Genomic characterization of two metagenome-assembled genomes of Tropheryma whipplei from China.

Whipple's disease is a rare chronic systemic disease that affects almost any organ system of the body caused by the intracellular bacterium Tropheryma whipplei, which is found ubiquitously in the environment. Sequencing of the T. whipplei genome has revealed that it has a reduced genome (0.93 Mbp), a characteristic shared with other intracellular bacteria. Until our research started, 19 T. whipplei strains had been sequenced from cultures originated in France, Canada, and Germany. The genome of T. whipplei bacterium has not been studied in Asia yet. Here, two metagenome-assembled genomes (MAGs) of T. whipplei from China were reconstructed through metagenomic next-generation sequencing (mNGS) and genome binning. We also provided genomic insights into the geographical role and genomic features by analyzing the whole genome. The whole-genome phylogenetic tree was constructed based on single-nucleotide polymorphism (SNP) distance calculations and then grouped by distance similarity. The phylogenetic tree shows inconsistencies with geographic origins, thus suggesting that the variations in geographical origins cannot explain the phylogenetic relationships among the 21 T. whipplei strains. The two Chinese strains were closely related to each other, and also found to be related to strains from Germany (T. whipplei TW08/27) and France (T. whipplei Bcu26 and T. whipplei Neuro1). Furthermore, the Average Nucleotide Identity (ANI) matrix also showed no association between geographic origins and genomic similarities. The pan-genome analysis revealed that T. whipplei has a closed pan-genome composed of big core-genomes and small accessory genomes, like other intracellular bacteria. By examining the genotypes of the sequenced strains, all 21 T. whipplei strains were found to be resistant to fluoroquinolones, due to the genetic mutations in genes gyrA, gyrB, parC, and parE. The 21 T. Whipplei strains shared the same virulence factors, except for the alpC gene, which existed in 7 out of the 21 T. whipplei strains. When comparing 21 entire T. whipplei pan-genomes from various nations, it was discovered that the bacterium also possessed a closed genome, which was a trait shared by intracellular pathogens.

Profiling of Serum Exosome MiRNA Reveals the Potential of a MiRNA Panel as Diagnostic Biomarker for Alzheimer's Disease.

Alzheimer's disease (AD) is the most common neurodegenerative disease in the older adults. Although much effort has been made in the analyses of diagnostic biomarkers, such as amyloid-ß, tau, and neurofilament light chain, identifying peripheral blood-based biomarkers is in extremely urgent need for their minimal invasiveness and more convenience. Here we characterized the miRNA profile by RNA sequencing in human serum exosomes from AD patients and healthy controls (HC) to investigate its potential for AD diagnosis. Subsequently, Gene Ontology analysis and pathway analysis were performed for the targeted genes from the differentially expressed miRNAs. These basic functions were differentially enriched, including cell adhesion, regulation of transcription, and the ubiquitin system. Functional network analysis highlighted the pathways of proteoglycans in cancer, viral carcinogenesis, signaling pathways regulating pluripotency of stem cells, and cellular senescence in AD. A total of 24 miRNAs showed significantly differential expression between AD and HC with more than ± 2.0-fold change at p value < 0.05 and at least 50 reads for each sample. Logistic regression analysis established a model for AD prediction by serum exosomal miR-30b-5p, miR-22-3p, and miR-378a-3p. Sequencing results were validated using quantitative reverse transcription PCR. The data showed that miR-30b-5p, miR-22-3p, and miR-378a-3p were significantly deregulated in AD, with area under the curve (AUC) of 0.668, 0.637, and 0.718, respectively. The combination of the three miRs gained a better diagnostic capability with AUC of 0.880. This finding revealed a miR panel as potential biomarker in the peripheral blood to distinguish AD from HC.

Exosome EpCAM promotes the metastasis of glioma by targeting the CD44 signaling molecule on the surface of glioma cells.

BACKGROUND: Glioma, the most common primary tumor in the central nervous system, originates from glial cells and has a poor prognosis. OBJECTIVES: This experimental laboratory study was designed to explore the role of epithelial cell adhesion molecule (EpCAM) in the metastasis of glioma. MATERIAL AND METHODS: Serum samples were collected from patients with non-metastatic or metastatic glioma (n = 20 per group), and healthy volunteers (n = 8). Exosomes were isolated from the serum and the morphological characteristics were observed under a scanning electron microscope (SEM). The expression of CD81 and CD63 was measured to identify exosomes. Glioma tissue and the adjacent normal tissue samples were obtained from patients with non-metastatic or metastatic glioma (n = 12 per group). Meanwhile, 4 normal brain tissue samples were collected. The expression of CD44, hyaluronan-mediated motility receptor (HMMR), and matrix metalloproteinase-9 (MMP-9) was determined in each group using immunohistochemistry. The protein expression of CD44, HMMR, matrix metalloproteinase-2 (MMP-2), MMP-9, and selectin E (SELE) was measured with western blotting. RESULTS: Exosomes were present in the serum, and the proteins CD81 and CD63 were expressed in all 3 groups. CD44 was highly expressed in the non-metastasis and metastasis groups. The expression of HMMR and MMP-9 in the Adj-metastasis and Adj-non-metastasis groups was high, while in the other groups, the levels were low. The expression of CD44 in the metastasis and non-metastasis groups was significantly higher than that of the negative control (NC) group, and the expression in the metastasis group was higher than that of the non-metastasis group. The MMP-2 and MMP-9 were not found in either the metastasis or non-metastasis group. The protein expression of HMMR and SELE was high in all groups. CONCLUSIONS: Exosome EpCAM promoted the metastasis of glioma by targeting CD44.

[Effects of hedyotis diffusa on mitochondrial membrane potential and expressions of apoptosis-related genes in human gastric cancer cell line MNK-45].

Objective: To investigate the effects of hedyotis diffusa (injection) on mitochondrial membrane potential and expressions of apoptosis-related genes in human gastric cancer cell line MNK-45 cells. Methods: The human gastric cancer MNK-45 cells were divided into 4 groups, each group was set with 3 replicates. The control group was MNK-45 cells without added hedyotis diffusa; the 3 groups of experimental groups were treated with hedyotis diffusa at final concentrations of 20 , 30, 40 µg / ml respectively; each group was incubated for 48 h in a 5% carbon dioxide incubator, and the morphological changes of the cells were observed under a laser confocal microscope. Mitochondrial membrane potential was detected by flow cytometry. The expressions of Cytochrome C (Cyt c), caspase3 and caspase9 genes and proteins were detected by qRT-PCR and Western blot respectively. Results: Compared with the control group, the mitochondrial membrane potentials of MNK-45 cells were significantly reduced in the hedyotis diffusa treated groups at final concentrations of 20, 30, and 40 µg / ml (P＜0. 01). The gene expressions of Cyt c, caspase3, and caspase9 were significantly up-regulated (P＜0. 01) and their protein expressions were also significantly increased (P＜0. 05 or P＜0. 01). The 40 µg / ml hedyotis diffusa treatment group performed best. Conclusion: In the final concentration range of 20 ~ 40 µg / ml, hedyotis diffusa can reduce human gastric cancer MNK-45 cells mitochondrial membrane potential, induce apoptosis and up-regulate Cyt c, caspase3 and caspase9 gene expressions.

MiR-34c acts as a tumor suppressor in non-small cell lung cancer by inducing endoplasmic reticulum stress through targeting HMGB1.

OBJECTIVE: To investigate the role of miR-34c in lung cancer. METHODS: The levels of microRNA-34c (miR-34c) expression in non-small cell lung cancer (NSCLC) tissue and cell lines were examined by the qRT-PCR assay. High mobility group box 1 (HMGB1) expression in NSCLC was assessed by immunohistochemical analysis (IHC), qRT-PCR, and Western blot assays. The effects of miR-34c overexpression or HMGB1 knockdown on cell proliferation and apoptosis were evaluated by CCK-8 and flow cytometry analysis, respectively. Cellular reactive oxygen species (ROS) production in NSCLC cells was detected using a ROS kit. The levels of Bax, p-ERK, eIF2α, GADD153, and IRE1α expression in treated NSCLC cells were measured by Western blot assays. In addition, the interaction between miR-34c and HMGB1 was verified by the dual-luciferase reporter assay. RESULTS: miR-34c was only slightly expressed, while HMGB1 was highly expressed in NSCLC tissues and cell lines. Overexpression of miR-34c or knockdown of HMGB1 inhibited cell proliferation, promoted cell apoptosis, and induced ER stress in NSCLC cells. In terms of mechanism, miR-34c negatively regulated HMGB1 expression by directly targeting the 3'-untranslated region (UTR) of HMGB1 mRNA. In addition, we proved that HMGB1 overexpression could block the effects of miR-34c on NSCLC cell proliferation, apoptosis, and ER stress. CONCLUSION: miR-34c may suppress NSCLC tumors by targeting HMGB1 mRNA, promoting endoplasmic reticulum stress, and increasing ROS levels. Our findings suggest that miR-34c has a role in NSCLC.

Upregulation of miR-1306-5p decreases cerebral ischemia/reperfusion injury in vitro by targeting BIK.

MiR-1306-5p is involved in the progression of acute heart failure, but its role in ischemic stroke remains unclear. Here, SH-SY5Y cells were exposed to oxygen-glucose deprivation (OGD) for 4, 8, and 12 h, respectively, and then reoxygenation for 12 h to construct OGD/R induced cell injury model. Cell viability, cell death, and cell apoptosis were assessed with CCK-8 assay, LDH assay, flow cytometry, and caspase-3 activity assay. The target gene of miR-1306-5p was confirmed by luciferase reporter assay. We found miR-1306-5p expression was significantly down-regulated in OGD/R-induced SH-SY5Y cell model. Moreover, miR-1306-5p protected SH-SY5Y cell against OGD/R-induced injury. Mechanistically, Bcl2-interacting killer (BIK) was the direct target gene of miR-1306-5p. Furthermore, BIK knockdown mimicked, while overexpression reversed the protective effects of miR-1306-5p against OGD/R induced injury. Our findings thus provide an experimental basis miR-1306-5p targeting BIK-based therapy for cerebral I/R injury.