H2S exerts its anti-inflammatory effect via several signal pathways, including preserving mitochondrial function in a p38 and JNK-MAPK dependent manner in microglia [99], inhibiting activation of NF-κB pathway in the hippocampus [100], suppressing phosphorylation of signal transducer and activator of transcription 3 (STAT3) and cathepsin S (Cat S) activation [101] in mouse models of AD. The gene discussed is STAT3; the disease is Alzheimer disease.