A lab study found that a modified version of the naturally occurring peptide humanin, called S14G‑humanin, can protect brain cells from damage caused by the Alzheimer‑related protein amyloid‑beta. In cultured hippocampal neurons, amyloid‑beta raised calcium inside the cells, created harmful oxidative stress, and lowered the mitochondria’s energy‑producing ability, but S14G‑humanin stopped these changes and restored normal cell function. The modified peptide was about a thousand times more potent than regular humanin.

Humanin is a potential therapeutic agent for Alzheimer's disease, and its derivative, S14G-humanin, is 1 000-fold stronger in its neuroprotective effect against Alzheimer's disease-relevant insults. Al-though effective, the detailed molecular mechanism through which S14G-humanin exerts its effects remains unclear. Data from this study showed that fibrillar amyloid-beta 40 disturbed cellular ho-meostasis through the cell membrane, increasing intracellular calcium, generating reactive oxygen species, and decreasing the mitochondrial membrane potential. S14G-humanin restored these responses. The results suggested that S14G-humanin blocked the effects of amyloid-beta 40 on the neuronal cell membrane, and restored the disturbed cellular homeostasis, thereby exerting a neu-roprotective effect on hippocampal neurons.