Neuroprotective Effect of Daidzein Extracted From Pueraria lobate Radix in a Stroke Model Via the Akt/mTOR/BDNF Channel

Daidzein is a plant isoflavonoid primarily isolated from Pueraria lobate Radix as the dry root of P. lobata (Wild.) Ohwi, have long been used as nutraceutical and medicinal herb in China. Despite the report that daidzein can prevent neuronal damage and improve outcome in experimental stroke, the mechanisms of this neuroprotective action have been not fully elucidated. The aim of this study was to determine whether the daidzein elicits beneficial actions in a stroke model, namely, cerebral ischemia/reperfusion (I/R) injury, and to reveal the underlying neuroprotective mechanisms associated with the regulation of Akt/mTOR/BDNF signal pathway. The results showed that I/R, daidzein treatment significantly improved neurological deficits, infarct volume, and brain edema at 20 and 30 mg/kg, respectively. Meanwhile, it was found out that the pretreatment with daidzein at 20 and 30 mg/kg evidently improved striatal dopamine and its metabolite levels. In addition, daidzein treatment reduced the cleaved Caspase-3 level but enhanced the phosphorylation of Akt, BAD and mTOR. Moreover, daidzein at 30 mg/kg treatment enhanced the expression of BDNF and CREB significantly. This protective effect of daidzein was ameliorated by inhibiting the PI3K/Akt/mTOR signaling pathway using LY294002. To sum up, our results demonstrated that daidzein could protect animals against ischemic damage through the regulation of the Akt/mTOR/BDNF channel, and the present study may facilitate the therapeutic research of stroke.

Bone mesenchymal stem cell-derived exosomal microRNA-7-5p inhibits progression of acute myeloid leukemia by targeting OSBPL11

Background Acute myeloid leukemia (AML) is a malignant clonal disease of hematopoietic stem- and progenitor-cell origin. AML features massive proliferation of abnormal blasts and leukemia cells in the bone marrow and the inhibition of normal hematopoiesis at onset. Exosomes containing proteins or nucleic acids are secreted by cells; they participate in intercellular communication and serve as key modulators of hematopoiesis. The purpose of this study was to investigate the effects of exosomes derived from bone marrow mesenchymal stem cells (BMSCs) on the regulation of AML and the underlying mechanisms mediated by microRNA (miRNA). Methods Dysregulated miR-7-5p in AML patients was identified using qRT-PCR and its clinical significance was explored. Bioinformatic analysis revealed the target gene OSBPL11 that could be regulated by miR-7-5p. The findings were validated using a dual-luciferase reporter assay and western blotting. The functional genes of the PI3K/AKT/mTOR signaling pathway were identified, and the functional significance of miR-7-5p in AML cells was determined using a functional recovery assay. AML cells were co-cultured with exosomes originating from BMSCs overexpressing miR-7-5p to determine cell–cell regulation by Exo-miR-7-5p, as well as in vitro and in vivo functional validation via gain- and loss-of-function methods. Results Expression of miR-7-5p was decreased in AML patients and cells. Overexpression of miR-7-5p curbed cellular proliferation and promoted apoptosis. Overexpression of OSBPL11 reversed the tumorigenic properties of miR-7-5p in AML cells in vitro. Exo-miR-7-5p derived from BMSCs induced formation of AML cells prone to apoptosis and a low survival rate, with OSBPL11 expression inhibited through the PI3K/AKT/mTOR signaling pathway. Exo-miR-7-5p derived from BMSCs exhibited tumor homing effects in vitro and in vivo, and inhibited AML development. Conclusions Exo-miR-7-5p derived from BMSCs negatively regulates OSBPL11 by suppressing the phosphorylation of the PI3K/AKT/mTOR signaling pathway, thereby inhibiting AML proliferation and promoting apoptosis. The data will inform the development of AML therapies based on BMSC-derived exosomes. Graphical Abstract

Astragalin Ameliorates Cognitive Dysfunction Through Inhibiting PI3K/Akt-MTOR-Mediated Autophagic Flow in Hippocampal Neurons of APP/PS1 Mice

Astragalin (AST), a natural small molecule flavonoid, can exert anti-oxidant, anti-inflammatory and anti-cancer impacts by regulating autophagy. However, the potential mechanism of the neuroprotective effect of AST on neurological disorders such as Alzheimer’s disease (AD) is still not clear. In the present study, we firstly screened AST for the treatment of AD from the ingredients of Chinese medicines such as Acori tataninowii Rhizoma, Eucommiae Cortex, Paeoniae Radix Alba through the traditional Chinese medicine systems pharmacology database and analysis platform (TCMSP) database. And then we found that AST could improve the cognitive abilities of APP/PS1 mice by Step-down passive avoidance (SDA) and Morris Water Maze (MWM) Test. Further, we identified that AST diminished Aβ plaques deposition in the brains of APP/PS1 mice and Aβ as well as Aβ42 levels in the serum of APP/PS1 mice. Next, microtubule-associated protein 1 light chain 3B (LC3B), p62, Beclin-1, ATG5, ATG12, LAMP-1 were observed to be co-expressed with NeuN in the hippocampus of APP/PS1 mice by immunofluorescent multiplex staining, while AST was able to activate autophagy and maintain autophagic flow in hippocampal neurons of APP/PS1 mice by western blot (WB) analysis. Finally, AST reduced the expressions of p-PI3K, p-Akt, p-mTOR by WB analysis. Taken together, we confirmed that AST may play key neuroprotective effects on APP/PS1 mice by inhibiting the PI3K/Akt-mTOR signaling pathway to activate autophagy and keep autophagic flow smooth.

miRNA-130 Promotes Migration and Angiogenesis of Endothelial Progenitor Cells Through PI3K/AKT/mTOR Pathways

<sec> <title>Aim:</title> In this study, we aimed to investigate the effects and mechanisms of miRNA-130a in human endothelial progenitor cells (EPCs) involved in Deep vein thrombosis (DVT). </sec> <sec> <title>Methods:</title> EPCs were isolated and identified by cell morphology and surface marker detection. The effect of miR-130a on the migration, invasion and angiogenesis of EPCs in vitro were also detected. In addition, whether miR-130a is involved in the MMP-1 expression and Akt/PI3K/mTOR signaling pathway was also demonstrated. </sec> <sec> <title>Results:</title> Results suggested that miRNA-130a promotes migration, invasion, and tube formation of EPCs by positively regulating the expression of MMP-1 through Akt/PI3K/mTOR signaling pathway. </sec> <sec> <title>Conclusion:</title> Thus, as a potential therapeutic target, miRNA-130a may play an important role in the treatment of DVT. </sec>

mTORC1 Signaling Pathway Mediated SIRT6 Overexpression in TGF-β1-Induced Pulmonary Fibrosis

Fibroblast-to-myofibroblast transdifferentiation and myofibroblast hyperproliferation play a major role in Idiopathic pulmonary fibrosis (IPF). It was also reported that mTOR signaling pathway and SIRT6 have a critical role in pulmonary fibrosis. However, the mechanisms whether mTOR signaling pathway and SIRT6 affect the myofibroblasts differentiation in IPF remain unclear. The results show that SIRT6 is significantly upregulated by TGF-β1 with a time and concentration-dependent manner in MRC5 line and primary lung fibroblasts isolated from IPF patients. SIRT6 protein is also increased in IPF fibrotic lung tissues and bleomycin-challenged mice lung tissues. Also, the activity of mTOR signaling is activated in MRC5 and primary lung fibroblasts. Furthermore, the inhibitor of mTOR, rapamycin treatment significantly suppress mTORC1 pathway activity and SIRT6 protein expression. SIRT6 siRNA failed to mediate the activity of mTORC1 pathway and autophagy induction. Finally, deficiency of SIRT6 could promote TGF-β1 induced pro-fibrotic cytokines. In summary, the study have suggested that SIRT6 is a downstream of mTORC1 signaling pathway in the pulmonary fibrosis caused by TGF-β1-induced. Deficiency of SIRT6 mediated myofibroblasts differentiation through induced pro-fibrotic cytokines production but not induced-autophagy. It was indicated that manipulations of SIRT6 expression may provide a new therapeutic strategy to reverse the progression of pulmonary fibrosis.