Knock-down of ROCK2 gene improves cognitive function and reduces neuronal apoptosis in AD mice by promoting mitochondrial fusion and inhibiting its division / 细胞与分子免疫学杂志

Objective To explore the effect of knocking down Rho-associated coiled-coil kinase (ROCK2) gene on the cognitive function of amyloid precursor protein/presenilin-1 (APP/PS1) double transgenic mice and its mechanism. Methods APP/PS1 double transgenic mice were randomly divided into AD model group (AD group), ROCK2 gene knock-down group (shROCK2 group), ROCK2 gene knock-down control group (shNCgroup), and wild-type C57BL/6 mice of the same age served as the wild-type control (WT group). Morris water maze and Y maze were employed to test the cognitive function of mice. Neuron morphology was detected by Nissl staining. Immunofluorescence histochemical staining was used to detect the expression of phosphorylated dynamin-related protein 1 (p-Drp1) and mitochondrial fusion 1 (Mfn1). Western blot analysis was used to detect the expression ROCK2, cleaved-caspase-3 (c-caspase-3), B-cell lymphoma 2 (Bcl2), Bcl2-related protein X (BAX), p-Drp1, mitochondrial fission 1 (Fis1), optic atrophy 1 (OPA1), Mfn1 and Mfn2. Results Compared with AD group mice, the expression of ROCK2 in shROCK2 group mice was significantly reduced; the cognitive function was significantly improved with the number of neurons in the hippocampal CA3 and DG areas increasing, and nissl bodies were deeply stained; the expression of c-caspase-3 and BAX was decreased, while the expression of Bcl2 was increased; the expression of mitochondrial division related proteins p-Drp1 and Fis1 were decreased, while the expression of mitochondrial fusion-related proteins OPA1, Mfn1 and Mfn2 were increased. Conclusion Knock-down of ROCK2 gene can significantly improve the cognitive function and inhibit the apoptosis of nerve cells of APP/PS1 mice. The mechanism may be related to promoting mitochondrial fusion and inhibiting its division.

Effects of astragaloside Ⅳ on inflammatory responses in astrocytes induced by lipopolysaccharide in vitro and its mechanism / 中华微生物学和免疫学杂志

Objective To investigate whether astragaloside ( AST) Ⅳ could inhibit lipopolysac-charide (LPS)-induced activation of astrocytes and the possible mechanism. Methods Effects of different concentrations of AST Ⅳ on astrocyte viability were determined by MTT to select the optimum concentration for the following experiments. Primary astrocytes were induced by LPS to construct the inflammatory model. Astrocytes were divided into three groups: PBS, LPS and LPS+ASTⅣ(LPS+ASTⅣ) groups. The release of nitric oxide (NO) was detected by Griess method. Expression of glial fibrillary acidic protein ( GFAP), an astrocyte marker, and TLR4 were analyzed by immunohistochemistry and Western blot. Cytokines of IL-6, TNF-α, IL-4 and IL-10 in the supernatants of cell culture for 24 h collected after stimulation were meas-ured by ELISA. Results ASTⅣsignificantly inhibited the LPS-induced activation of astrocytes and NO re-lease (P<0. 01), suppressed the expression of TLR4 (P<0. 05) and reduced the secretion of IL-6 (P<0. 01) and TNF-α (P<0. 01), but increased the secretion of IL-4 and IL-10 (P<0. 05 and P<0. 01). Con-clusion AST Ⅳ could significantly inhibit the LPS-induced activation of astrocytes and suppress inflamma-tory responses, and the possible mechanism might be related to reduced secretion of inflammatory factors af-ter blocking the expression of TLR4.