miR-19a/b-3p promotes inflammation during cerebral ischemia/reperfusion injury via SIRT1/FoxO3/SPHK1 pathway.

BACKGROUND: Stroke affects 3-4% of adults and kills numerous people each year. Recovering blood flow with minimal reperfusion-induced injury is crucial. However, the mechanisms underlying reperfusion-induced injury, particularly inflammation, are not well understood. Here, we investigated the function of miR-19a/b-3p/SIRT1/FoxO3/SPHK1 axis in ischemia/reperfusion (I/R). METHODS: MCAO (middle cerebral artery occlusion) reperfusion rat model was used as the in vivo model of I/R. Cultured neuronal cells subjected to OGD/R (oxygen glucose deprivation/reperfusion) were used as the in vitro model of I/R. MTT assay was used to assess cell viability and TUNEL staining was used to measure cell apoptosis. H&E staining was employed to examine cell morphology. qRT-PCR and western blot were performed to determine levels of miR-19a/b-3p, SIRT1, FoxO3, SPHK1, NF-κB p65, and cytokines like TNF-α, IL-6, and IL-1ß. EMSA and ChIP were performed to validate the interaction of FoxO3 with SPHK1 promoter. Dual luciferase assay and RIP were used to verify the binding of miR-19a/b-3p with SIRT1 mRNA. RESULTS: miR-19a/b-3p, FoxO3, SPHK1, NF-κB p65, and cytokines were elevated while SIRT1 was reduced in brain tissues following MCAO/reperfusion or in cells upon OGD/R. Knockdown of SPHK1 or FoxO3 suppressed I/R-induced inflammation and cell death. Furthermore, knockdown of FoxO3 reversed the effects of SIRT1 knockdown. Inhibition of the miR-19a/b-3p suppressed inflammation and this suppression was blocked by SIRT1 knockdown. FoxO3 bound SPHK1 promoter and activated its transcription. miR-19a/b-3p directly targeted SIRT1 mRNA. CONCLUSION: miR-19a/b-3p promotes inflammatory responses during I/R via targeting SIRT1/FoxO3/SPHK1 axis.

CircFN1 upregulation initiated oxidative stress-induced apoptosis and inhibition of proliferation and migration in trophoblasts via circFN1-miR-19a/b-3p-ATF2 ceRNA network.

Recently, the etiopathogenesis of preeclampsia (PE) has been developed from the perspective of circular RNA, microRNA and their crosstalk in placental oxidative stress. Real-time quantitative PCR and western blotting detected expression of circular RNA-fibronectin 1 (circFN1; ID hsa_circ_0058152), microRNA (miR)-19a/b-3p and activating transcription factor 2 (ATF2). Receiver operating characteristic (ROC) curve analyzed the predictive value of circFN1. Oxidative stress, apoptosis, proliferation, and migration were measured using superoxide dismutase (SOD) and malonaldehyde (MDA) assay kits, Annexin V/Prodium iodide and western blotting methods, MTS and EdU assays, and scratch wound assay, respectively. Target relationships were retrieved by miRNA target prediction software and confirmed by dual-luciferase reporter assay, RNA immunoprecipitation and RNA pull-down. Expression of circFN1 was upregulated in the serum of PE pregnancies, and the area under the ROC curve of serum circFN1 was 0.7826 (95% confidence interval: 0.6495-0.9157; sensitivity 86.96%; specificity 56%). Functionally, its upregulation decreased SOD activity, cell viability, EdU incorporation, migration rate, and Bcl-2 expression in human trophoblast HTR-8/SV-neo cells, but meanwhile increased MDA level, apoptosis rate, and Bax and cleaved-caspase3 expression. Moreover, its downregulation played the opposite effects in HTR-8/SV-neo cells. Mechanistically, circFN1 functioned as "miRNA sponge" for miR-19a/b-3p and modulated the latter's target gene ATF2. There were feedback effects of miR-19a/b-3p restorations and ATF2 depletion on circFN1 actions in HTR-8/SV-neo cells. Oxidative injury-mediated placental trophoblast dysfunction in PE was through competing endogenous RNA (ceRNA) mechanism of CircFN1-miR-19a/b-3p-ATF2 axes.

Circulating miR-19a-3p and miR-19b-3p characterize the human aging process and their isomiRs associate with healthy status at extreme ages.

Blood circulating microRNAs (c-miRs) are potential biomarkers to trace aging and longevity trajectories to identify molecular targets for anti-aging therapies. Based on a cross-sectional study, a discovery phase was performed on 12 donors divided into four groups: young, old, healthy, and unhealthy centenarians. The identification of healthy and unhealthy phenotype was based on cognitive performance and capabilities to perform daily activities. Small RNA sequencing identified 79 differentially expressed c-miRs when comparing young, old, healthy centenarians, and unhealthy centenarians. Two miRs, that is, miR-19a-3p and miR-19b-3p, were found increased at old age but decreased at extreme age, as confirmed by RT-qPCR in 49 donors of validation phase. The significant decrease of those miR levels in healthy compared to unhealthy centenarians appears to be due to the presence of isomiRs, not detectable with RT-qPCR, but only with a high-resolution technique such as deep sequencing. Bioinformatically, three main common targets of miR-19a/b-3p were identified, that is, SMAD4, PTEN, and BCL2L11, converging into the FoxO signaling pathway, known to have a significant role in aging mechanisms. For the first time, this study shows the age-related increase of plasma miR-19a/b-3p in old subjects but a decrease in centenarians. This decrease is more pronounced in healthy centenarians and was confirmed by the modified pattern of isomiRs comparing healthy and unhealthy centenarians. Thus, our study paves the way for functional studies using c-miRs and isomiRs as additional parameter to track the onset of aging and age-related diseases using new potential biomarkers.