Overview
Following systemic administration, PE-22-28 must cross the blood-brain barrier — its shorter peptide sequence relative to full-length spadin improves CNS penetration. It binds TREK-1 channels in their extracellular domain, stabilizing the closed-channel conformation. This leads to increased dorsal raphe nucleus firing rates, elevation of hippocampal extracellular 5-HT, and downstream increases in BDNF via TrkB/CREB signaling. TREK-1 inhibition also has reported effects on HPA axis regulation, potentially reducing corticosterone hypersecretion under stress.
Proposed mechanism
PE-22-28 acts as a selective inhibitor of the TREK-1 (TWIK-related K+ channel 1) two-pore domain potassium channel, which plays a major role in regulating neuronal excitability and serotonergic tone. By blocking TREK-1, PE-22-28 increases serotonin availability at synapses in limbic and prefrontal regions, mimicking the antidepressant effects observed in TREK-1 knockout mice. This mechanism is distinct from SSRIs and monoamine oxidase inhibitors, as it targets upstream potassium channel regulation rather than serotonin reuptake transporters directly.
What the evidence supports
Most data comes from preclinical animal studies. Human clinical trial evidence is limited or absent.
Graded Animal
Evidence drawn from in vivo animal models or in vitro systems. Mechanistically informative; translation to humans is unproven.
Key citations
Representative primary sources, including results that did not favour the compound.
- [1]
Spadin, a sortilin-derived peptide, targeting rodent TREK-1 channels: a new concept in the antidepressant drug design
· PLoS Biology, Mazella J et al., doi:10.1371/journal.pbio.1000355 · 2010
- [2]
Antidepressant properties of the spadin peptide and its shorter analog PE-22-28
· Frontiers in Pharmacology, Djillani A et al. · 2016
- [3]
TREK-1 is a heat-activated background K+ channel
· EMBO Journal, Maingret F et al. · 2000
- [4]
Deletion of the background potassium channel TREK-1 results in a depression-resistant phenotype
· Nature Neuroscience, Heurteaux C et al. · 2006
Citation records in this build are illustrative placeholders for the design.
Reference information for research purposes. Not medical advice, and not a recommendation to use any compound. Many entries describe substances that are not approved for human use.