Humanin

Humanin is a 24-amino acid peptide encoded within the mitochondrial 16S ribosomal RNA gene, making it one of the first identified mitochondrial-derived peptides (MDPs). Its discovery revealed that the mitochondrial genome, long thought to encode only oxidative phosphorylation components, produces bioactive peptide signals.

The peptide was originally identified through its ability to protect neurons from amyloid-beta toxicity in Alzheimer's disease models. Research has since demonstrated broad cytoprotective effects mediated through multiple mechanisms, including binding to pro-apoptotic BAX protein (preventing mitochondrial membrane permeabilization), activation of STAT3 signaling, and interaction with the receptor complex formed by CNTFR, WSX-1, and gp130.

Beyond neuroprotection, humanin demonstrates metabolic effects including improved insulin sensitivity and glucose homeostasis. Circulating humanin levels decline with age and correlate with metabolic health markers, suggesting a role in age-related metabolic decline.

Research has identified numerous humanin analogs with enhanced potency, including HNG (Ser14Gly), which is 1000-fold more potent than native humanin. These analogs have become valuable tools for studying humanin biology and developing potential interventions for neurodegenerative and metabolic diseases.