DNSP-11
DNSP-11, dopamine neuron stimulating peptide-11, GDNF propeptide, proGDNF-derived peptide
DNSP-11 is an eleven-amino-acid peptide cut from the propeptide region of GDNF, the growth factor precursor, rather than from the mature growth factor itself. In rats it protects and stimulates dopamine neurons after a single injection into the substantia nigra. Its receptor is unknown, the literature is very thin, and it has never been given to a human.
Mechanism
Glial cell line-derived neurotrophic factor is among the most potent known dopaminergic neurotrophic factors, and its clinical development has been repeatedly frustrated by delivery. GDNF is a large, heavily charged, disulfide-bonded dimer that does not cross the blood-brain barrier and diffuses poorly through brain parenchyma, and the intraputaminal infusion trials in Parkinson's disease produced equivocal results. DNSP-11 comes from a different idea: that the propeptide region of the precursor, ordinarily regarded as a discarded chaperone sequence, carries neurotrophic activity of its own. It is an eleven-residue sequence within the proregion of the 211-amino-acid human pre-proGDNF, predicted to be liberated by endopeptidase cleavage at flanking dibasic sites and then amidated at the C-terminus. Being small and easy to synthesise, it sidesteps GDNF's delivery problem.
The most striking feature of its pharmacology is what is missing. The originating work reported that DNSP-11 does not appear to signal through GFR-alpha1, the canonical GDNF co-receptor that partners with the RET tyrosine kinase. Its actions persisted where GDNF's did not: it blocked staurosporine- and gramicidin-induced cytotoxicity in nutrient-deprived dopaminergic B65 cells, which GDNF failed to do, and it prevented cytochrome c release from mitochondria, pointing to a direct anti-apoptotic action upstream of caspase activation. More than fifteen years after its description, the receptor and proximal signalling mechanism of DNSP-11 remain genuinely unidentified. That is an unusual and important gap for a compound being sold to consumers.
What the research shows
Bradley's 2010 paper in PLoS One is the foundation and remains the main evidence. In vitro, DNSP-11 increased survival and neurite outgrowth of fetal mesencephalic neurons and protected MN9D cells against 6-hydroxydopamine toxicity, with significantly fewer TUNEL-positive cells and reduced caspase-3 activity. In vivo, a single injection into the substantia nigra of normal adult rats was rapidly taken up into neurons and raised resting dopamine and dopamine metabolite levels for up to 28 days, a notably long effect for an 11-residue peptide. In a 6-hydroxydopamine rat model of Parkinson's disease it significantly improved apomorphine-induced rotational behaviour and increased nigral dopamine and metabolite tissue levels. Stenslik's 2015 paper developed repeated intranasal delivery in the same rat model, addressing the practical route problem.
Beyond these, the literature is close to empty. Searching PubMed for DNSP-11 returns a handful of records dominated by the originating University of Kentucky group. There is no independent replication of the behavioural findings by an unaffiliated laboratory, no non-human primate efficacy study that could be verified in the peer-reviewed record, and no trial registered on ClinicalTrials.gov for any indication. The 2010 authors declared pending patents relating to the findings. DNSP-11 is a genuinely interesting scientific idea, that a growth factor's discarded propeptide has independent activity, supported by one strong paper and remarkably little since. Fifteen years of near-silence after a promising result is itself informative, and usually means the effect proved difficult to build on.
Evidence assessment
Preclinical only
One substantive primary publication and a small methods follow-up, all in rat models and cell culture from a single institution; there is no registered clinical trial, no human data, and no independent replication of the behavioural findings.
Tiers are applied consistently across the library and re-checked when new trials read out. Read the grading method.
Key studies
Dopamine neuron stimulating actions of a GDNF propeptide Preclinical only
DNSP-11 increased neuronal survival and neurite outgrowth, protected against 6-OHDA toxicity with reduced TUNEL positivity and caspase-3 activity, raised resting nigral dopamine and metabolites for up to 28 days after a single injection, and improved apomorphine-induced rotational behaviour; effects appeared not to require GFR-alpha1.
Methodology and effects of repeated intranasal delivery of DNSP-11 in a rat model of Parkinson's disease Preclinical only
Established a repeatable intranasal delivery method and reported effects in the rat Parkinson's model, addressing the route-of-administration problem.
Safety
No human safety data of any kind exist. Every published in vivo experiment used direct intracranial injection or intranasal delivery in rats. Nothing is known about systemic exposure, repeat dosing, immunogenicity, blood-brain barrier penetration in humans, or long-term effects. Marketing of DNSP-11 for neuroregeneration, neuroprotection or cognitive enhancement has no evidential basis whatsoever: the compound has never been administered to a human being in any published study, so there is not even an anecdotal safety record to draw on. Any material available to consumers is manufactured outside pharmaceutical GMP with no assurance of identity, purity, sterility or endotoxin content, which matters particularly for anything represented as suitable for administration near the central nervous system.
Regulatory status
| Jurisdiction | Status |
|---|---|
| United Kingdom | No MHRA authorisation and no UK clinical trials. Not an authorised medicine; supply for human use would engage the Human Medicines Regulations 2012. |
| United States | Not FDA-approved and not in clinical development. No investigational new drug programme or registered clinical trial exists. Sold as a research chemical. |
| WADA (sport) | Not individually named on the Prohibited List. As a substance with no regulatory approval for human therapeutic use it would fall within S0, prohibited at all times. |
Questions
No. There are no registered clinical trials on ClinicalTrials.gov and no published human studies of any kind. All in vivo evidence comes from rats, given the peptide either by direct injection into the substantia nigra or intranasally. There is no human safety record, not even anecdotal.
It is not a fragment of the mature growth factor. It comes from the propeptide region of pre-proGDNF, the precursor sequence that is normally cleaved away and discarded during processing. The claim that this discarded region has independent neurotrophic activity is what makes the compound scientifically interesting, and it also means DNSP-11 should not be expected to behave like GDNF.
Nobody knows. The originating work specifically concluded that its actions do not appear to require GFR-alpha1, the canonical GDNF co-receptor, and no alternative receptor has been identified in the fifteen years since. Its anti-apoptotic effect appears to act upstream of mitochondrial cytochrome c release, but the proximal target remains unidentified.
That is a fair question and the answer is not flattering to the compound. After a strong 2010 paper the literature largely stopped, with only a delivery-methods follow-up from the same institution and no independent replication of the behavioural findings. When a promising neuroscience result attracts almost no follow-up over fifteen years, the usual explanation is that it proved hard to build on, though absence of publication is not proof of failure.