Description
Summary Abstract
KPV (Lys-Pro-Val; H-Lys-Pro-Val-OH; C16H30N4O4; MW 342.44 g/mol; CAS 66003-55-2; PubChem CID 107910) is the C-terminal tripeptide fragment (residues 11–13) of alpha-melanocyte-stimulating hormone (α-MSH), generated endogenously from the pro-opiomelanocortin (POMC) precursor. Structure-activity relationship studies established that KPV retains the full anti-inflammatory and antimicrobial pharmacophore of the parent α-MSH molecule while lacking the high-affinity melanotropic activity that limits systemic use of the full-length hormone. KPV’s principal anti-inflammatory mechanism involves direct intracellular competition with the p65/RelA subunit of Nuclear Factor-kappa B (NF-κB) for the nuclear transport protein Importin-α3, physically blocking NF-κB nuclear translocation and suppressing downstream transcription of pro-inflammatory cytokines including TNF-α, IL-1β, IL-6, and IL-8. A secondary pathway involves surface agonism at the Melanocortin 1 Receptor (MC1R), elevating intracellular cAMP and providing complementary immune suppression. KPV is also actively transported into inflamed intestinal epithelial cells via the H+-coupled oligopeptide transporter PepT1, which is upregulated in colitis tissue, providing a disease-targeting pharmacological advantage. Capsule oral delivery exploits this PepT1 mechanism for gut-directed delivery, while lyophilized KPV supports parenteral or topical research applications.
Clinical Indications
KPV has been investigated across inflammatory, infectious, and mucosal disease contexts:
- Inflammatory Bowel Disease (IBD) — Ulcerative Colitis and Crohn’s Disease: In DSS-induced murine colitis models, KPV-loaded PLGA-HA nanoparticles significantly reduced TNF-α, IL-1β, and IL-6 in colonic tissue, preserved crypt architecture, and prevented neutrophil infiltration; active therapeutic concentrations were achieved at doses 12,000-fold lower than free KPV using CD44-targeted nanoparticles.
- Dermatology — Psoriasis and Wound Healing: Topical KPV reduces psoriatic plaque scaling, erythema, and induration by inhibiting the NF-κB → IL-8 → IL-23 → IL-17 feed-forward loop in keratinocytes; antimicrobial biofilm inhibition supports wound-healing applications in diabetic ulcers and burns.
- Vulvovaginal Candidiasis (VVC): The (CKPV)₂ dimer (CZEN-002) achieved an 88% cure rate in a Phase 1/2a clinical trial for VVC by reducing fungal burden via cAMP-mediated pathway disruption and promoting anti-inflammatory M2 macrophage polarization.
- Airway Inflammation — COPD and Asthma: KPV inhibited IL-8, eotaxin, and TNF-α secretion in human bronchial epithelial cells stimulated by TNF-α and RSV through receptor-independent Importin-α3 blockade, acting even in cells with downregulated MC3R.
Contraindications
- Active Systemic Infection with Inadequate Antimicrobial Coverage: While KPV has direct antimicrobial properties, NF-κB suppression during active bacterial sepsis without concomitant antibiotic coverage could theoretically limit the early neutrophil response needed for pathogen clearance.
- Known Hypersensitivity to Melanocortin Peptide Fragments: Individuals with confirmed allergy to α-MSH-derived compounds or related nanoparticle excipients (e.g., PLGA, hyaluronic acid) should be evaluated prior to administration.
- Autoimmune Uveitis (theoretical; melanocyte proximity): MC1R activation on melanocytes and immune cells near the uveal tract warrants assessment before ocular administration in autoimmune settings.
Mechanism of Action (MOA)
KPV operates through three convergent, multi-modal pathways that collectively suppress pathological inflammation while preserving host defense:
Intracellular NF-κB Blockade via Importin-α3 Competition
KPV penetrates the cytoplasm and binds to Importin-α3, the transport protein that shuttles the p65/RelA subunit of NF-κB through nuclear pores. By occupying the Importin-α3 binding site, KPV physically prevents NF-κB nuclear translocation, halting transcription of pro-inflammatory genes. Dose-dependent reduction of IL-8, eotaxin, and TNF-α was demonstrated in airway epithelial cells. This mechanism is receptor-independent, conferring efficacy even when surface melanocortin receptors are downregulated by chronic inflammation.
MC1R Surface Agonism — cAMP-Mediated Immune Suppression
KPV binds to the Melanocortin 1 Receptor (MC1R) on melanocytes, keratinocytes, macrophages, and neutrophils, activating adenylyl cyclase and elevating intracellular cAMP. Elevated cAMP serves as a potent inhibitory second messenger in immune cells, reducing inflammatory granule release and cytokine secretion. This complementary surface pathway provides a second layer of anti-inflammatory activity.
PepT1-Mediated Active Transport in Inflamed Mucosa
As a tripeptide substrate for the H+-coupled oligopeptide transporter PepT1, KPV is actively transported into intestinal epithelial cells. In colitis, PepT1 expression is markedly upregulated in the colon (normally restricted to the small intestine), creating a disease-targeted delivery mechanism that concentrates KPV at sites of active inflammation with minimal systemic exposure. This pharmacological advantage distinguishes KPV from most immunosuppressants that require systemic distribution.
Antimicrobial — cAMP Dysregulation in Fungi; Charge-Based Membrane Disruption
KPV’s net positive (cationic) charge at physiological pH enables electrostatic interaction with the negatively charged membranes of bacteria and fungi. Against Candida albicans, KPV induces abnormal cAMP elevation within the fungal cell, blocking the yeast-to-hypha transition required for tissue invasion. The engineered (CKPV)₂ dimer exhibits enhanced potency against drug-resistant C. krusei by increasing charge density and metabolic stability.
Key Features & Specifications
Pharmacological and structural attributes of KPV:
Chemical Analysis
| Property | Specification Reference Data |
|---|---|
| Sequence | H-Lys-Pro-Val-OH (KPV tripeptide; C-terminal α-MSH fragment 11–13) |
| CAS Number | 66003-55-2 |
| Molecular Formula | C16H30N4O4 |
| Molecular Weight | 342.44 g/mol |
| PubChem CID | 107910 |
| Synonyms | Lys-Pro-Val; KPV peptide; α-MSH (11-13); CZEN-002 dimer (modified derivative) |
| Form / Variation | 10 MG Lyophilized (P-023) / 500 MCG Capsules (C-018) |
Storage, Safety, and Handling
Storage Protocol
Store lyophilized KPV at −20 °C in a sealed container, protected from light and moisture; stable for ≥24 months under these conditions. Capsules should be stored at room temperature (15–25 °C) in a dry environment away from direct light. Reconstituted KPV solutions should be stored at 2–8 °C and used within 7–14 days; the small tripeptide is more stable than larger peptides but is still susceptible to proteolytic degradation in biological fluids.
Handling & Compliance
Handle reconstituted solutions with sterile technique and standard PPE. KPV is not classified as a prohibited substance by WADA and has an established safety profile from clinical trials of the CZEN-002 dimer (Phase 1/2a, 88% VVC cure rate, no serious adverse events). The regulatory pathway for nanotechnology-based KPV formulations (PLGA-HA nanoparticles) involves evaluation of both the active peptide and delivery-vehicle components under FDA/EMA biologics/combination product frameworks.