NAP, a peptide derived from the activity-dependent neuroprotective protein, modulates macrophage function.

NAP is an eight-amino acid neuroprotective peptide NAPVSIPQ; it is the smallest active element derived from the recently cloned activity-dependent neuroprotective protein (ADNP). NAP readily enters the brain from the blood. It will be important to learn whether NAP, in addition to its neuroprotective activity, also might influence immune-mediated inflammation. Here, we report that: (a) macrophages express ADNP; (b) expression of ADNP in macrophages responds to VIP; and (c) NAP downregulates the key inflammatory cytokines tumor necrosis factor (TNF-alpha), interleukin-16 (IL-16), and IL-12 in macrophages. These findings indicate that ADNP/NAP can play an important role in immune regulation as well as in neuroprotection, which may be mutually related processes.