Study on the Mechanism of BMSCs in Regulating NF-κB Signal Pathway by Targeting miR-449a to Improve the Inflammatory Response to Peripheral Nerve Injury.

OBJECTIVE: To evaluate the mechanism of Bone Marrow Mesenchymal Stem Cells (BMSCs) in regulating NF-κB signal pathway by targeting miR-449a. METHODS: Stem cells were transfected by over-expressing and inhibiting miR-449a to detect the levels and viability of miR-449a in stem cells after transfection. Stem cells and neurons were co-cultured in vitro to evaluate the in vitro mechanism of stem cells over-expressing miR-449a on neurons. RESULTS: After the addition of neurons, the neuronal activity of miR-449a over-expression group increased significantly, the expression of NF-κB signal pathway proteins (IκBα, p50, and p65) decreased, and the inflammatory cytokines (TNF-α and IL-1ß) decreased significantly (P<0.05). In vivo experiments in rats also showed that rats were unresponsive, did not chirp or elude after being stimulated. After stem cell therapy, the weight and response of rats gradually returned to normal levels. miR-449a expression significantly increased in the stem cell + miR-449a over-expression group, expression of NF-κB signal pathway proteins (IκBα, p50, and p65) decreased, inflammatory cytokines (TNF-α and IL-1ß) significantly decreased, and cell activity significantly increased (P<0.05). CONCLUSIONS: BMSCs can modulate NF-κB signaling pathway by targeting miR-449a, so as to reduce the inflammatory response to peripheral nerve injury and repair nerve injury.

Exercise Regulates the Lactate Receptor HCAR1 and ERK1/2-PI3K/Akt Pathways to Promote Cerebral Angiogenesis.

Background: We aimed to explore the ole and mechanism of lactate receptor (HCAR1) in the angiogenesis of leptomeningeal fibroblast-like cells. Methods: Human brain fibroblast-like cells were selected and some cells were deactivated, analyzed and compared with HCAR1 mRNA and protein expressions in deactivated/normal cells. HCAR1-/- mice and wild type (WT) mice were selected and divided into WT, WT exercise, HCAE1 KO and HCAE1 KO exercise groups, with 10 mice for each group. HCAR1mRNA and expression levels of proteins in fibroblast-like cells, mRNA and expression levels of proteins in Collagen IV, phosphatidylinositol trihydroxykinase (PI3K), serine threonine kinase (AKT) and extracellular signal-regulated kinases 1 and 2 (ERK1/2) in hippocampus were compared, and the microvessel density (MVD) and diameter were calculated. Results: mRNA and expression levels of proteins in Collagen IV, PI3K, AKT, ERK1/2 and MVD in hippocampus were significantly higher in the WT exercise group than those in the WT group, microvessel diameter was significantly lower than that in the WT group (P<0.05). mRNA and expression levels of proteins in Collagen IV, PI3K, AKT, ERK1/2 and MVD in hippocampus in the HCAR1 KO and HCAR1 KO exercise groups were significantly lower than those in the WT group, microvessel diameter was higher than that in the WT group (P<0.05). Compared with the HCAR1 KO exercise group, the changes of mRNA in Collagen IV, PI3K, AKT, ERK1/2 and microvascular were not significant. Conclusion: Exercise can promote cerebral angiogenesis through the activation of the lactate receptor HCAR1 and the ERK1/2-PI3K/Akt signaling pathways.

Neuroprotective Effects of Probiotic-Supplemented Diet on Cognitive Behavior of 3xTg-AD Mice.

Alzheimer's disease (AD) is recognized as one of the most common types of senile dementia. AD patients first suffer memory loss for recent events (short-term memory impairment). As the disease progresses, they are deprived of self-awareness. This study aims to explore the effects of a probiotic-supplemented diet on the cognitive behaviors and pathological features of mouse models of Alzheimer's disease (AD). Mice in the control group and the 3xTg-AD group were fed a regular diet and a probiotic-supplemented diet, respectively, for 20 weeks. Behavioral experiments like Morris's water maze and Y maze were conducted. Then, feces of mice were collected for 16S sRNA gene sequencing for microorganisms. In the end, soluble and insoluble Aß40 and Aß42 in the hippocampus and cortex of mice in each group were quantitatively analyzed with a double-antibody Sandwich ELISA. The expression levels of tau protein and gliocyte in the hippocampus and cortex were detected using the Western Blot method. The result of the Morris water maze experiment indicated that, in the place navigation test, the mice in the 3xTg-AD group experienced a significant decline in the learning ability and a longer escape latency and in the space exploration test, the swimming time of mice in the 3xTg-AD group in the target quadrant decreased and after being treated with the probiotic diet, mice in the 3xTg-AD group had improved learning and memory ability. The result of Y maze showed that the probiotic diet can improve the spontaneous alternation accuracy of mice in the 3xTg-AD group. The result of 16s rRNA gene sequencing showed that, compared with mice in the WT group, those in the 3xTg-AD group experienced a change in the intestinal flora. The Western Blot result displayed a decreased expression level of tau (pS202) (P < 0.05) and decreased expression levels of Iba-1 and GFAP (P < 0.05). The result of the ELISA experiment showed decreased levels of soluble and insoluble Aß40 and Aß42 in 3xTg-AD mice (P < 0.05). In conclusion, a probiotic diet can prevent and treat AD by improving the intestinal flora of 3xTg-AD.

MicroRNA-140 silencing represses the incidence of Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative condition leading to severe disability from progressive impairments in cognitive functions including memory and learning. Non-coding microRNAs (miRNAs or miRs) have been linked to the pathogenesis of AD. The present study aimed to investigate the clinical significance and biological function of miR-140 in AD. First, we examined the expression of miR-140 and PINK1 in brain tissues of the established AD model rats and neurons cultured with Aß-derived diffusible ligands (AßDDLs). We identified an interaction between miR-140 and PINK1, and measured spatial learning and memory abilities of the model rats using the Morris water maze (MWM) test. After ectopic expression and depletion experiments in neurons and AD rats, we measured the levels of reactive oxygen species (ROS), and mitochondrial membrane potential (MMP), along with mTOR expression and phosphorylation, and autophagy-related factors. Results showed up-regulation of miR-140 and down-regulation of PINK1 in AD model rats and neurons. PINK1 was verified to be a direct target of miR-140, and silencing of miR-140 suppressed mitochondrial dysfunction, and enhanced autophagy in AD model rats and neurons, as supported by decreased levels of mTOR expression and phosphorylation, ß-amyloid p-Tau (Ser396), p-Tau (Thr231), Tau and ROS, and increased MMP levels and expression of Beclin 1 expression and LC3-II/LC3-I. Collectively, functional suppression of miR-140 enhanced autophagy and prevented mitochondrial dysfunction by upregulating PINK1, ultimately suggesting a novel therapeutic target for AD.