Humanin
Research Guide

What is humanin?

Humanin is a 24-amino-acid peptide, MAPRGFSCLLLLTSEIDLPVKRRA (PubChem CID 16131438), encoded by a short open reading frame in MT-RNR2, the mitochondrial gene for 16S ribosomal RNA (Bodzioch et al., 2009; Cobb et al., 2016). It was identified in 2001 by functional expression screening as a secreted factor that blocked neuronal cell death caused by familial Alzheimer's disease genes and amyloid-β (Hashimoto et al., 2001a), and reviews describe it as the first of the mitochondrial-derived peptides (Lee et al., 2013).

Much of the animal work used the analog S14G-humanin (HNG), so each summary names the compound tested. Disguised Alpha supplies wild-type humanin as a lyophilized powder for laboratory research use only. Nothing on this page is guidance for use in people.

Humanin reference data

Formula, molecular weight, peptide class, size and storage are from the Humanin product page. PubChem CID 16131438 lists the same formula and weight and gives the sequence. PubChem also files trifluoroacetate-salt synonyms under that record, and salt forms add mass, so confirm identity and measured content against your lot's certificate.

See it beside the other compounds on this site in the peptide molecular weight reference table.

What the research covers

Published work on humanin falls into six areas. Each summary below states the model used.

Discovery and the mitochondrial genome

In the founding study, cells transfected with humanin cDNA secreted the peptide, which protected neuronal cells from familial Alzheimer's disease genes and amyloid-β but not from polyglutamine or SOD1-mutant toxicity (Hashimoto et al., 2001a).

The mitochondrial genome carries an identical reading frame (Guo et al., 2003), and the human nuclear genome adds 13 MT-RNR2-like loci predicted to encode humanin-like peptides, at least ten expressed in human tissues (Bodzioch et al., 2009). In rat cells, predicted to lack such nuclear copies, humanin production fell when mitochondrial DNA was depleted, was unaffected by the cytosolic translation blocker cycloheximide, and localized to mitochondria (Paharkova et al., 2015).

Structure-activity work and the S14G analog (HNG)

In neuronal cell culture, the domain from Pro3 to Pro19 carried the rescue activity, Cys8 and Ser14 were essential, and among factors compared, including IGF-I and basic FGF, only HNG blocked all five insults tested (Hashimoto et al., 2001b). HNG, like humanin with D-serine at position 14, was two to three orders of magnitude more potent than wild-type humanin, and self-dimerization through Ser7 was essential for activity (Terashita et al., 2003).

Intracellular binding partners

Humanin bound the pro-apoptotic protein Bax, kept it from moving to mitochondria and blocked cytochrome c release from isolated mitochondria (Guo et al., 2003). It also bound Bid and its truncated form tBid, even blocking tBid-driven release of cytochrome c from Bax-deficient mitochondria (Zhai et al., 2005), and bound the extra-long isoform of Bim but not the shorter ones (Luciano et al., 2005).

Models: purified proteins, cell lines and isolated mitochondria. A yeast two-hybrid screen found IGFBP-3 as a high-affinity partner; a non-binding F6A mutant failed to block IGFBP-3-induced apoptosis in A172 glioblastoma cells, and in mouse primary neurons IGFBP-3 strengthened humanin's rescue from amyloid-β (Ikonen et al., 2003).

Cell-surface receptors

Synthetic humanin drew mononuclear phagocytes through human formyl peptide receptor-like 1 (FPRL1) and mouse FPR2, receptors amyloid-β42 also uses (Ying et al., 2004). In CHO cells expressing FPRL1, humanin had a half-maximal concentration of 3.5 nM and an N-formylated form 0.012 nM (Harada et al., 2004). In neuronal cells, gp130 was essential for protection, CNTF receptor alpha and WSX-1 took part in binding, and humanin made the three assemble in reconstituted assays (Hashimoto et al., 2009).

Rodent metabolic and cardiac models

In male Sprague-Dawley rats studied with insulin clamps, centrally infused humanin raised whole-body insulin sensitivity through hypothalamic STAT-3, and potent analogs given peripherally reproduced the effect (Muzumdar et al., 2009). In male C57BL/6J mice subjected to coronary occlusion and reperfusion, HNG reduced infarct size relative to the area at risk and raised left ventricular ejection fraction a week later (Muzumdar et al., 2010).

Aging studies in animals and human cohorts

Humanin raised cognitive test scores in aged mice, and a variant in its mitochondrial coding region (rs2854128) was tied to lower circulating humanin and, in an independent cohort of older adults, faster cognitive aging (Yen et al., 2018). Overexpression extended lifespan in C. elegans, and the same paper reported humanin falling with age in several species but higher in children of centenarians than in controls (Yen et al., 2020).

A cross-sectional study of 693 people aged 21 to 113 found the opposite, with plasma humanin highest in centenarians (Conte et al., 2019). The direction of change with age is unsettled. Authors of the first two studies declared ties to CohBar Inc.

Tumor models

In triple-negative breast cancer cells, added humanin protected the cells from apoptotic stimuli, while silencing it reduced their viability. In tumor-bearing mice, systemic humanin reduced tumor apoptosis, blunted the effect of chemotherapy and accelerated tumor growth (Moreno Ayala et al., 2020). Models: breast cancer cell lines and mice.

Key studies

1. Hashimoto Y, et al. "A rescue factor abolishing neuronal cell death by a wide spectrum of familial Alzheimer's disease genes and Abeta." Proc Natl Acad Sci U S A. 2001. PMID 11371646. DOI 10.1073/pnas.101133498. Founding report: neuronal cell culture.
2. Guo B, et al. "Humanin peptide suppresses apoptosis by interfering with Bax activation." Nature. 2003. PMID 12732850. DOI 10.1038/nature01627. Cell lines and isolated mitochondria.
3. Ikonen M, et al. "Interaction between the Alzheimer's survival peptide humanin and insulin-like growth factor-binding protein 3 regulates cell survival and apoptosis." Proc Natl Acad Sci U S A. 2003. PMID 14561895. DOI 10.1073/pnas.2135111100. Yeast two-hybrid, cell lines and mouse neurons.
4. Terashita K, et al. "Two serine residues distinctly regulate the rescue function of Humanin, an inhibiting factor of Alzheimer's disease-related neurotoxicity: functional potentiation by isomerization and dimerization." J Neurochem. 2003. PMID 12787071. DOI 10.1046/j.1471-4159.2003.01797.x. Neuronal cell culture: Ser14 analogs.
5. Ying G, et al. "Humanin, a newly identified neuroprotective factor, uses the G protein-coupled formylpeptide receptor-like-1 as a functional receptor." J Immunol. 2004. PMID 15153530. DOI 10.4049/jimmunol.172.11.7078. Human and mouse phagocytes.
6. Hashimoto Y, et al. "Humanin inhibits neuronal cell death by interacting with a cytokine receptor complex or complexes involving CNTF receptor alpha/WSX-1/gp130." Mol Biol Cell. 2009. PMID 19386761. DOI 10.1091/mbc.e09-02-0168. Neuronal cells, binding assays.
7. Muzumdar RH, et al. "Humanin: a novel central regulator of peripheral insulin action." PLoS One. 2009. PMID 19623253. DOI 10.1371/journal.pone.0006334. Rats: insulin clamps.

Handling and storage of lyophilized humanin

General laboratory practice for this material:

• Store the lyophilized powder at -20°C, protected from light, until use (storage guidance on the product page), and let the sealed vial reach room temperature before opening.
• The N-terminal methionine and the free cysteine at position 8 are oxidation-prone, and Cys8 was essential for activity in cell assays (Hashimoto et al., 2001b), so limit air, light and oxidizers and prepare working solutions fresh.
• Activity depended on self-dimerization (Terashita et al., 2003), and four consecutive leucines make part of the peptide hydrophobic, so keep solvent, pH and concentration consistent across comparisons.
• Humanin binds IGFBP-3 with high affinity (Ikonen et al., 2003), so serum in the medium may shift the free concentration.
• A mass check separates humanin from HNG, which is about 30 g/mol lighter (PubChem).
• After reconstitution, keep solutions at 2 to 8°C, protected from light, in single-use aliquots to avoid freeze/thaw cycles.
• Record the lot number and use the certificate's measured content, not the label mass, for molar calculations.

Frequently asked questions

What is humanin?

Humanin is a 24-residue peptide, MAPRGFSCLLLLTSEIDLPVKRRA, encoded in the mitochondrial 16S rRNA gene and first described as a secreted factor that blocked Alzheimer's disease-related neuronal death in cell culture (Hashimoto et al., 2001a).

Is humanin a mitochondrial-derived peptide?

Yes. Its reading frame lies in mitochondrial DNA, and reviews call it the first mitochondrial-derived peptide (Lee et al., 2013). The human nuclear genome also carries 13 similar loci (Bodzioch et al., 2009), but in rat cells, predicted to lack such copies, humanin was made inside mitochondria (Paharkova et al., 2015).

Humanin vs MOTS-c: what is the difference?

Both are mitochondrial-derived peptides from different genes. Humanin, from the 16S rRNA gene, binds apoptosis proteins and IGFBP-3 and signals through FPRL1 and a gp130-containing receptor complex. MOTS-c is a 16-residue peptide from the 12S rRNA gene, found by searching mitochondrial DNA for more reading frames like humanin's, and reported to act through the folate cycle and AMPK, mainly in skeletal muscle (Lee et al., 2015). See our MOTS-c research guide.

What is HNG (S14G-humanin)?

HNG is humanin with glycine in place of serine at position 14. It was two to three orders of magnitude more potent in neuronal cell assays (Terashita et al., 2003), and it was the form tested in the mouse heart study above (Muzumdar et al., 2010). It is a different molecule (PubChem CID 16135997), not the wild-type humanin sold here.

How should humanin powder be stored?

Keep the lyophilized powder at -20°C and protected from light. After reconstitution, store the solution at 2 to 8°C, protected from light, and avoid freeze/thaw cycles, as listed on the product page.

Where can researchers buy humanin?

Disguised Alpha sells wild-type humanin for laboratory research in a 10MG vial, third-party tested with the certificate published on the product page: Humanin (Mitochondrial Bioregulator).

Related compounds and guides

• MOTS-c and its research guide: another mitochondrial-derived peptide
• SS-31 and its research guide: a synthetic mitochondria-targeted peptide
• NAD+ and its research guide
• COA portal: every published certificate, by lot

This product is for research use only. It has not been evaluated for safety or effectiveness in humans. Not for human consumption. All products are intended for laboratory research purposes only.

Research basics

• What are peptides?
• What is a certificate of analysis (COA)?
• What does lyophilized mean?
• What are peptide bioregulators?
• Peptide glossary: research terms defined
• Peptide calculator: concentration and volume
• Peptide molecular weight calculator