24-residue mitochondrial-derived peptide (MDP)

Our opinion on this compoundEstablished, active research

56/100

Founding mitochondrial-derived peptide with elegant multi-target biology but thin human translation

Look, humanin is one of those compounds where the biology is genuinely exciting and the clinical story is genuinely disappointing, and you have to hold both of those at the same time. Discovered in 2001 by Hashimoto’s group at Keio in a screen for factors that could rescue neurons from amyloid-beta toxicity, it’s the founding member of the mitochondrial-derived peptide family, a class we now know includes MOTS-c, the SHLP peptides, and gau. The fact that the mitochondrial genome encodes bioactive signaling peptides at all was the paradigm-interesting discovery. Humanin was the first proof of that concept.

The mechanism is what keeps us interested. Humanin isn’t doing one thing. It’s binding BAX and BIM directly in the cytoplasm to suppress pro-apoptotic signaling, engaging the CNTFR-WSX-1-gp130 heterotrimeric receptor complex on the membrane, and activating FPR2, a receptor with broad relevance to inflammation and cytoprotection. Multi-compartment, multi-receptor, with downstream effects that span neuroprotection, insulin sensitivity in rodent obesity models, and cytoprotection against ischemic and chemotherapy-induced injury. Thats a genuinely interesting pharmacological signature. The S14G substitution (HNG) delivers roughly 1000-fold potency improvement in neuroprotection assays and is the right research-grade form to reach for if you’re running in vitro or rodent work.

The evidence picture is solid at the preclinical level. Multiple labs have replicated the core anti-apoptotic and neuroprotective findings, and the rodent metabolic data is reasonably clean. What’s missing is the human side. Clinical development has been limited, the PK characterization in humans is sparse, and there are no phase 2 readouts to point at. Observational work has established that circulating humanin levels decline with age and track with disease-associated phenotypes, but that’s a far cry from interventional data. We’ve seen this story before with other peptides: strong rodent, weak translation, and a long wait for someone to run a proper human pharmacology study.

As a bench tool, humanin earns its place. It’s the reference probe for MDP biology and an essential comparator if you’re working anywhere near the mitochondrial-derived peptide space. The BAX/BIM binding angle also makes it useful as a probe for Bcl-2 family apoptosis work, and the CNTF receptor engagement gives it orthogonal utility in neurotrophin biology. What we like is the specificity and the multi-target readouts you get with HNG. What we don’t like is the clinical silence after 25 years of preclinical work. Humanin is firmly in the category of compounds that deserve more rigorous human pharmacology than they’ve gotten. Whether that will happen is still an open question.

Novelty: 52
Mechanism promise: 74
In-category differentiation: 65
Evidence quality: 42
Translational signal: 35
Research bench value: 65

Rationale Humanin is the reference compound for the MDP class, with a genuinely sophisticated multi-receptor mechanism and solid multi-lab preclinical base, but it’s been around since 2001 and clinical development has stalled; the score reflects strong bench utility and mechanism quality offset by weak translational signal and diminishing novelty relative to newer MDPs like MOTS-c.

24-residue mitochondrial-derived peptide (MDP)

A 24-amino-acid peptide encoded within the 16S rRNA of the mitochondrial genome, identified as a neuroprotective and metabolic factor with broad anti-apoptotic activity.

Abstract

Humanin (Met-Ala-Pro-Arg-Gly-Phe-Ser-Cys-Leu-Leu-Leu-Leu-Thr-Ser-Glu-Ile-Asp-Leu-Pro-Val-Lys-Arg-Arg-Ala; molecular weight 2687.27 free peptide; CAS 330936-69-1) is a 24-residue peptide encoded within the 16S ribosomal RNA gene of the mitochondrial genome, identified by Yuichi Hashimoto and colleagues at Keio University in 2001 in a screen for anti-apoptotic factors that protected against amyloid-beta-induced neuronal death. Humanin is the founding member of the mitochondrial-derived peptide (MDP) family, a class of peptides encoded within mitochondrial DNA and translated from short open reading frames in mitochondrial RNAs; other family members include MOTS-c (KDC-MN-008), the SHLP family (small humanin-like peptides 1 through 6), and gau (gene antisense ubiquitous). The pharmacological signature of humanin includes anti-apoptotic activity through binding the BAX and BIM Bcl-2 family pro-apoptotic proteins, suppression of caspase activation, neuroprotection against amyloid-beta, prion peptide, and ALS-associated SOD1 toxicity in rodent and cell culture models, modulation of metabolic phenotypes (improved insulin sensitivity in rodent obesity models), and cytoprotection in models of myocardial ischemia and chemotherapy-induced toxicity. Receptors include the heterotrimeric ciliary neurotrophic factor (CNTF) receptor complex (CNTFR-WSX-1-gp130), the formyl peptide receptor 2 (FPR2), and direct cytoplasmic protein-protein interactions with BAX/BIM. The S14G analog of humanin (HNG; gly substituted for ser at position 14) is approximately 1000-fold more potent in neuroprotection assays and is the principal research-grade analog used in pharmacology studies. The compound is research-grade with no regulatory approval; clinical development has been limited despite the strong preclinical signal, attributed in part to the narrow therapeutic window for neurodegenerative disease drugs and the sparse human pharmacokinetic characterization.

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Tag: 24-residue mitochondrial-derived peptide (MDP)

Humanin

Abstract

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