Humanin

Humanin is a 24-amino-acid peptide discovered in 2001 by Hashimoto, Nishimoto and colleagues in Tokyo, who were screening for genes that stopped nerve cells dying in cell models of Alzheimer's disease (Hashimoto et al., PNAS 2001). Its sequence is encoded in the mitochondrial 16S ribosomal RNA gene, with matching sequences in nuclear DNA, and it was the first of a small group of 'mitochondrial-derived peptides' to be described. Most research is in cultured cells and in mice and rats, and many animal studies use modified versions such as HNG (S14G-humanin) or the hybrid peptide colivelin rather than humanin itself. In rodents, humanin infused into the brain raised whole-body insulin sensitivity in clamp studies (Muzumdar et al., PLoS One 2009). In people, the work is observational: studies measure natural humanin levels in blood, and they disagree, with one reporting lower levels with age and others higher levels with age. We found no published studies giving humanin to people, so whether the cell and animal findings apply to humans, and its human safety and pharmacokinetics, are unknown. Supplied for laboratory research use only.