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MicroRNAs (miRNAs) regulate protein expression by antagonizing the translation of mRNAs and are effective regulators of normal nervous system development, function, and disease. MicroRNA-29b (miR-29b) plays a broad and critical role in brain homeostasis. In this study, we tested the function of miR-29b in animal and cell models by inhibiting miR-29b expression. Mouse models of middle cerebral artery occlusion were established using the modified Zea-Longa suture method. Prior to modeling, 50 nmol/kg miR-29b antagomir was injected via the tail vein. MiR-29b expression was found to be abnormally increased in ischemic brain tissue. The inhibition of miR-29b expression decreased the neurological function score and reduced the cerebral infarction volume and cell apoptosis. In addition, the inhibition of miR-29b significantly decreased the malondialdehyde level, increased superoxide dismutase activity, and Bcl-2 expression, and inhibited Bax and Caspase3 expression. PC12 cells were treated with glutamate for 12 hours to establish in vitro cell models of ischemic stroke and then treated with the miR-29 antagomir for 48 hours. The results revealed that miR-29b inhibition in PC12 cells increased Bcl-2 expression and inhibited cell apoptosis and oxidative damage. These findings suggest that the inhibition of miR-29b inhibits oxidative stress and cell apoptosis in ischemic stroke, producing therapeutic effects in ischemic stroke. This study was approved by the Laboratory Animal Care and Use Committee of the First Affiliated Hospital of Zhengzhou University (approval No. 201709276S) on September 27, 2017.

Precartilaginous stem cells (PSCs) are adult stem cells which could initiate chondrocytes and bone growth. In the current study, we purified PSCs from the neonate mice' perichondrial mesenchyme through immunomagnetic beads with the fibroblast growth factor receptor-3 (FGFR-3) antibody. Mouse PSCs were seeded and cultured, and their phenotype was confirmed by FGFR-3 over-expression. Transforming growth factor-β (TGF-β) was added to induce PSCs differentiation. TGF-β increased mRNA expression of chondrogenesis-related genes (collagen type II, Sox 9, and aggrecan) in the cultured PSCs, which was abolished by TGF-β receptor II (TGFRII) lentiviral shRNA depletion. TGF-β induced AKT activation in mouse PSCs, while the PI3K/AKT inhibitor (LY294002) and the AKT specific inhibitors (perifosine and MK-2206) largely suppressed TGF-β-induced collagen II, Sox 9, and aggrecan mRNA expression. Meanwhile, the mTOR complex 1 (mTORC1) blocker RAD001 or the mTORC1/2 dual inhibitor AZD-2014 also alleviated TGF-β-induced chondrogenesis-associated genes expression. Further, lentiviral shRNA depletion of SIN1 (a mTORC2 component) or mTOR inhibited TGF-β's effect in the mouse PSCs. In conclusion, our evidence suggests that TGF-β induces the expression of chondrogenesis-related genes through TGFRII-AKT-mTOR signaling in cultured mouse PSCs. [ABSTRACT FROM AUTHOR]