Adiponectin Protects against Glutamate-Induced Excitotoxicity via Activating SIRT1-Dependent PGC-1 Expression in HT22 Hippocampal Neurons

Figure 5

SIRT1 siRNA inhibited the expression of SIRT1 and PGC-1α and restrained the protective effects of the APN peptide against Glu-induced damage in HT22 cells. HT22 cells were transfected with siRNA targeting SIRT1 or negative control siRNA for 24 h and then exposed to 500 μM APN peptide for 24 h, followed by exposure to 5 mM Glu for 24 h. (a) Cell viability is shown in OD. Silencing SIRT1 reversed the protective effects of the APN peptide against Glu-induced HT22 cell death. (b) LDH release was tested by a LDH release assay and the results are expressed as multiples of the control levels. Silencing SIRT1 also weakened the effects of the APN peptide and decreased Glu-induced LDH release. (c) Western blot analysis of SIRT1 and PGC-1α expressions after siRNA transfection; the cellular levels of SIRT1 and PGC-1α both decreased significantly. (d) SIRT1 expression level. (e) PGC-1α expression level. The results are expressed as mean ± SD. ; versus the Glu + control siRNA group; versus the 500 μM APN peptide + control siRNA group; versus the Glu + SIRT1 siRNA group. APN, adiponectin; OD, optical density; LDH, lactate dehydrogenase; SIRT1, silent information regulator 1; PGC-1α, peroxisome proliferator-activated receptor gamma coactivator 1-alpha.

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