Meeting Abstract
Aging is characterized by the accumulation of biomolecular damage, which leads to reduced function. Dietary restriction extends lifespan in many species, and the feeding stimulant hormone Neuropeptide F (NPF; homolog of NPY in vertebrates) is hypothesized to participate. A few studies have shown that NPF/Y improves proteostasis. Here, we test whether supplemental NPF and feeding level interact to reduce accumulation of carbonyls (oxidized proteins). For 32 d prior to dissection, middle-aged female grasshoppers were reared either on life-extending dietary restriction or an ad libitum diet. Grasshoppers on dietary restriction typically consumed all their daily food in 5-6 h. For 16 d prior to dissection, grasshoppers were injected daily with either 100 pmol truncated NPF (YSQVARPRFa), truncated shortNPF (SPSLRLRFa), or water. Grasshoppers were fed in the morning and injected in the afternoon. This temporal separation avoided weakening of the peptide signal by responsive feeding. In ad libitum-fed grasshoppers, injection of NPF, but not shortNPF, increased feeding on 5 of 6 days tested (P<0.05). Carbonyls were analyzed by immunoblot. In gut, carbonyl levels were reduced by dietary restriction (P>0.0001) and by shortNPF injection (P=0.0016), but not their interaction and not by NPF. In fat body, there was a significant interaction of feeding level and injection type (P<0.0001); upon ad libitum feeding either shortNPF or NPF increased carbonyl levels, but upon dietary restriction NPF decreased carbonyl levels. In head neural tissues, neither feeding level nor injection affected carbonyl levels. These results suggest that NPF with dietary restriction, or perhaps shortNPF alone, can reduce protein oxidation in specific tissues. These results are consistent with NPF and shortNPF contributing to biomolecular maintenance and longevity.
