Hormesis effect of hydrogen peroxide on the promoter activity of neuropeptide receptor PAC1-R

Pituitary adenylate cyclase-activating polypeptide (PACAP) receptor 1 (PAC1-R) is the neuropeptide PACAP-preferring receptor-mediating neuroprotective activity. In order to clarify the biological mechanism of its expression, we cloned the 2,526 bp promoter fragment from -2,500 to +26 of the transcription initiation site of human ADCYAP1R1 gene and constructed the novel promotor reporter system named pYr-PromDetect-PAC1p. It was found in SH-SY5Y cells low concentration (<10 nM) of hydrogen peroxide (H₂ O₂ ) significantly promoted the activity of PAC1-R promoter in dose-dependent way, which was significantly inhibited by the transcription factor specificity protein 1 (SP1) inhibitor mithramycin A and was further confirmed in the deletion mutation of the predicted SP1 binding sites. Moreover, higher concentration of H₂ O₂ (>10 nM) inhibited the activity of PAC1-R in dose-dependent way. The hormesis effect of H₂ O₂ on PAC1-R promoter would help to further clarify the physiological effect of low-dose reactive oxygen on nervous system. PRACTICAL APPLICATIONS: PAC1-R mediates well-known neuroprotective, neurotrophic, and neurogenesis effects, which is an important drug target for neurodegenerative diseases. The hormesis effects of oxidative stress on PAC1-R expression not only help to explain the hormesis effects of oxidative stress on nerve system, but also offer a novel strategy to increase the expression of PAC1-R for the nerve protection or nerve generation. For example, taking advantage of low degree of oxidative stress to increases the expression of PAC1-R might help prevent subsequent surgical serious injury on the nervous system. The activation of PAC1-R promoter by low concentration of H₂ O₂ would help to further clarify the physiological effect of low-dose reactive oxygen on nervous system.