Characterization of the Effects of a Humanin Fragment Peptide (HNF14) in Age-Related Macular Degeneration

TL;DR

A short Humanin-derived peptide, HNF14, reduces cellular stress and protects AMD-affected retinal cells, suggesting potential for treating age-related macular degeneration.

Contribution

Demonstrates that a short Humanin fragment retains cytoprotective effects in AMD-specific mitochondrial models.

Findings

HNF14 improved metabolic activity and reduced cytotoxicity in AMD cybrids.

HNF14 reduced oxidative stress, apoptotic signaling, and VEGF-A expression in AMD cybrids.

HNF14 attenuated amyloid-β-induced apoptosis in AMD cybrids.

Abstract

Background: Age-related macular degeneration (AMD) is a leading cause of vision loss and is strongly associated with mitochondrial dysfunction in retinal pigment epithelial cells. Mitochondrial-derived peptides, including Humanin and its analogs, have demonstrated cytoprotective effects in AMD-related cellular models. However, the effects of shorter Humanin-derived fragments in disease-specific mitochondrial models remain incompletely characterized. Methods: Transmitochondrial retinal pigment epithelial cybrid cell lines containing mitochondria from AMD patients or age-matched normal donors were treated with HNF14, a 14-amino acid Humanin fragment peptide. Cellular metabolic activity, cytotoxicity, oxidative stress, apoptotic signaling, inflammatory markers, angiogenic factor expression, and amyloid-β1–42-induced apoptosis were evaluated using biochemical assays, protein analyses, and live-cell imaging approaches. Results: HNF14 treatment was associated with improved metabolic activity and reduced cytotoxicity in AMD cybrids, with minimal effects in normal cybrids. HNF14 significantly reduced intracellular and mitochondrial oxidative stress, suppressed apoptotic and inflammatory markers, and decreased VEGF-A protein expression in AMD cybrids. In addition, HNF14 attenuated amyloid-β1–42-induced apoptotic signaling in AMD cybrids. These effects were selective for cybrids containing AMD-derived mitochondria. Conclusions: This study demonstrates that HNF14 mitigates mitochondrial and cellular stress responses in AMD transmitochondrial cybrid cells. The findings indicate that a short Humanin-derived fragment retains cytoprotective activity in a disease-specific mitochondrial context and support further investigation of mitochondrial-derived peptides as modulators of mitochondrial dysfunction relevant to AMD pathophysiology.

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