PE-22-28: Research & Studies

Research Overview#

PE-22-28 has a limited but promising preclinical evidence base. It was described in a single primary publication (Djillani et al., 2017) as an optimized analog of spadin (Mazella et al., 2010). The evidence demonstrates potent and selective TREK-1 channel blockade, antidepressant-like behavior in standard mouse models, and rapid induction of hippocampal neurogenesis. However, all data comes from a single research group, with no independent replication or human studies.

Primary Study: Djillani et al. (2017)#

The definitive characterization of PE-22-28 (PMID: 28955242) demonstrated that this 7-amino acid fragment of spadin retained full TREK-1 blocking activity with dramatically improved properties:

• Potency: IC50 of 0.12 nM at TREK-1, representing a 300-500 fold improvement over spadin
• Selectivity: Specific for TREK-1 over other two-pore domain potassium channels tested
• Stability: Extended duration of action from 7 hours (spadin) to 23 hours
• Antidepressant activity: Significant reduction in immobility time in the forced swimming test at 3-4 mcg/kg IP
• Neurogenesis: Hippocampal neurogenesis induced after only 4 days of treatment
• Synaptogenesis: Increased PSD-95 expression in cortical neurons

Foundation: Spadin Discovery (Mazella et al., 2010)#

The parent compound spadin was discovered by Mazella and colleagues (PMID: 20405001) as a naturally occurring peptide derived from the propeptide of sortilin. This study established TREK-1 as a target for antidepressant development and demonstrated that spadin-mediated TREK-1 blockade could induce rapid antidepressant effects and neurogenesis in mice.

Evidence Quality Assessment#

The evidence level is low due to data originating from a single laboratory with no independent replication. While the pharmacological characterization (patch-clamp electrophysiology, binding assays) is rigorous, the behavioral data relies on standard but limited paradigms (FST, NSF). No pharmacokinetic studies, dose-response relationships, or toxicology data have been published.

Research Gaps#

Key gaps include the absence of independent replication, no human data of any kind, limited understanding of chronic TREK-1 blockade consequences, and no formal pharmacokinetic or toxicology studies.

Research Evidence Context#

PE-22-28 belongs to the Neuropeptide category of research peptides. The research evidence for PE-22-28 spans multiple study types and endpoints. Researchers should evaluate the strength of evidence based on study design, sample size, and publication status when drawing conclusions about efficacy and safety.

Key Clinical Studies#

The following studies provide the clinical evidence base for PE-22-28:

Shortened spadin analogs display better TREK-1 inhibition, in vivo stability and antidepressant activity#

Authors: Djillani A, Pietri M, Moreno S, et al. (2017) — Frontiers in Pharmacology

Designed and characterized PE-22-28, a 7-amino acid spadin analog with 300-500x improved TREK-1 affinity (IC50 0.12 nM), extended duration of action (23 hours), and antidepressant activity in mice.

Key Findings:

• PE-22-28 IC50 of 0.12 nM at TREK-1, vs 40-60 nM for spadin
• Significant reduction in forced swimming test immobility time at 3-4 mcg/kg IP
• Duration of action extended to 23 hours (vs 7 hours for spadin)
• Induced hippocampal neurogenesis after 4 days of treatment
• Enhanced synaptogenesis (increased PSD-95 expression) in cortical neurons
• Selective for TREK-1 over other two-pore domain potassium channels

Limitations: Single research group; mouse models only; limited behavioral paradigms; no pharmacokinetic data; no chronic dosing studies; no toxicology data

Spadin, a sortilin-derived peptide, targeting rodent TREK-1 channels: a new concept in the antidepressant drug design#

Authors: Mazella J, Petrault O, Lucas G, et al. (2010) — PLoS Biology

Original discovery of spadin as a natural TREK-1 blocker derived from the sortilin propeptide. Demonstrated antidepressant activity and neurogenesis in mice, establishing the foundation for PE-22-28 development.

Key Findings:

• Spadin binds TREK-1 with affinity of ~10 nM
• Blocked TREK-1 activity in COS-7 cells and hippocampal neurons
• 4-day IV treatment produced strong antidepressant effects in mice
• Enhanced hippocampal CREB phosphorylation and neurogenesis
• Established TREK-1 as a viable antidepressant drug target

Limitations: Spadin had limited in vivo stability (7-hour duration); parent compound from which PE-22-28 was subsequently derived

Evidence Quality Assessment#

The overall evidence level for PE-22-28 is classified as low. Available research includes limited clinical data, typically from small or early-phase studies. More rigorous clinical trials are needed to draw definitive conclusions.

Research Gaps and Future Directions#

The following gaps in the current evidence base for PE-22-28 have been identified:

• No human clinical trials or safety data
• All data from a single research group at Universite Cote d'Azur
• No chronic dosing or long-term safety studies
• Unknown effects of sustained TREK-1 blockade on neuroprotection and pain processing
• No pharmacokinetic characterization (absorption, distribution, metabolism, excretion)
• No independent replication of antidepressant findings

Addressing these research gaps will be important for establishing a more complete understanding of PE-22-28's therapeutic potential and safety profile.

Related Reading#

• PE-22-28 overview and research guide
• PE-22-28 dosing protocols
• PE-22-28 molecular structure