Hydrogen sulfide protects amyloid-β induced cell toxicity in microglia

Alzheimer's disease (AD) is pathologically characterized by the accumulation of senile plaques, containing activated microglia and amyloid-β peptides (Aβ). We found that aggregated Aβ1-40 peptide (25 μM, 24 h) significantly decreased viability of BV-2 microglial cells. This was concentration-dependently attenuated by NaHS (a hydrogen sulfide (H2S) donor, 25-500 μM). NaHS also significantly attenuated Aβ-induced LDH release and the up-regulation of protein expression of growth arrest DNA damage (GADD 153). These data suggest that H2S may attenuate Aβ-induced cell toxicity and cell cycle re-entry. Pretreatment with NaHS also suppressed the release of nitric oxide and the upregulation of inducible nitric oxide synthase. These effects were attenuated by exogenous application of NaHS or stimulation of endogenous generation of H2S with S-adenosyl-L-methionine, a cystathionine β synthase activator. NaHS also decreased the releases of TNF-α and suppressed the up-regulation of protein expression of cyclooxygenase 2, which were mimicked by blockade of p38 and JNK-MAPK. In addition, Aβ induced loss of mitochondrial member potential (ΔΨm) and activation of p38-, JNK-, and ERK-MAPKs. Application of NaHS attenuated these effects but failed to affect the activation of ERK. In conclusion, we demonstrated for the first time that H2S may protect cell against Aβ-induced cell injury by inhibition of inflammation, promotion of cell growth and preservation of mitochondrial function in a p38- and JNK-MAPK dependent manner. Our results suggest that H2S may have potential therapeutic value for treatment of AD.