Quick Answer
KPV is the last three residues of alpha-MSH, a peptide in the melanocortin system. The research interest is that this fragment appears to retain the anti-inflammatory character reported for the parent peptide while lacking the sequence responsible for pigmentation signalling. Most published work is in vitro or in animal colitis models and centres on NF-kB pathway activity. It is unrelated to BPC-157 despite the two being frequently discussed together.
KPV is three amino acids long: lysine, proline, valine. That is the entire molecule. It is one of the smallest compounds in the research peptide market, and the reason it is studied at all is a specific and rather elegant observation about where anti-inflammatory activity sits within a larger parent peptide.
The melanocortin system
The melanocortin system is a signalling network built around a family of peptides derived from a single precursor protein, proopiomelanocortin. Enzymatic processing of that precursor yields several products, among them adrenocorticotropic hormone and the melanocyte stimulating hormones. Alpha-MSH, the one relevant here, is a 13 residue peptide.
As Catania et al. (2004) review, these peptides act at five melanocortin receptors, MC1R through MC5R, distributed across different tissues. MC1R on melanocytes is the receptor most people have heard of, because it is the one associated with pigmentation. Others are associated with adrenal function, energy balance, exocrine tissue and immune cells. The system is therefore not one pathway but several, sharing a family of ligands.
Alongside pigmentation and metabolic signalling, alpha-MSH has an extensive literature as an anti-inflammatory mediator, with reported effects on cytokine production and on the NF-kB signalling pathway that governs much of the inflammatory transcriptional response, summarised in a review by Brzoska et al. (2008).
Why a three residue fragment
The structure of alpha-MSH can be read as regions with different functions. The core sequence in the middle of the molecule is the part principally associated with melanocortin receptor binding and the pigmentation signal. The C terminal end, the final three residues, is KPV.
The research observation that generated interest, reported in an early mouse ear-swelling study by Hiltz and Lipton (1989), is that KPV alone appears to retain a meaningful portion of the anti-inflammatory activity reported for the whole peptide, while lacking the region that drives pigmentation signalling. If that separation holds, it allows the inflammatory question to be studied without the pigmentary one, which is scientifically useful in a way that a full length peptide is not.
The mechanism by which a tripeptide achieves this is not fully resolved, and the honest position is that competing explanations exist. Work in intestinal and airway epithelial cell lines reports intracellular activity affecting NF-kB pathway signalling rather than classical receptor mediated action at the cell surface: Dalmasso et al. (2008) traced KPV uptake through the PepT1 transporter, and Land (2012) linked its effect to blocked nuclear entry of an NF-kB subunit. Mouse studies by Getting et al. (2003) and Kannengiesser et al. (2008) found KPV still active in animals without a functional MC1R, and the first of these proposed interference with interleukin-1 beta signalling instead. This is an active question, not a settled one.
Why so much of the work is intestinal
A researcher new to KPV is often surprised by how heavily the literature concentrates on the gut. Two reasons explain it.
The first is transport. KPV is small enough to be a plausible substrate for peptide transporters, and PepT1, expressed in the small intestine and induced in the inflamed colon, has been examined directly as a route by which KPV reaches intestinal cells. A compound that can be delivered to the tissue of interest is a compound that gets studied in that tissue.
The second is readout quality. Animal colitis models and intestinal epithelial cell lines are well characterised systems for measuring inflammatory signalling. If the question is whether a compound modulates NF-kB driven inflammation, these are among the cleanest places to ask it. The concentration of work in the gut reflects experimental convenience as much as any claim about where KPV is uniquely relevant.
What KPV is not
Two clarifications save a lot of confusion.
| Compound | Length | Studied in |
|---|---|---|
| KPV | 3 residues | Inflammatory signalling, NF-kB pathway |
| BPC-157 | 15 residues | Tissue repair and angiogenesis |
| Alpha-MSH | 13 residues | Melanocortin receptor signalling including pigmentation |
| Melanotan analogues | Varies | MC1R agonism and pigmentation |
It is not BPC-157
The two are constantly named in the same breath in gut related discussion. They have no mechanistic relationship. BPC-157 is a 15 residue sequence associated with a protein found in gastric juice, and its literature sits mainly in tissue repair and angiogenesis. KPV is a melanocortin fragment studied in inflammatory signalling. Sharing a research context is not sharing a mechanism, and findings do not transfer between them.
It is not a melanotan
Melanotan compounds are melanocortin agonists designed to drive MC1R signalling and pigmentation. KPV is the fragment of the same parent peptide that specifically lacks that capability. They come from the same family and were developed with opposite intentions.
Reading the evidence
The KPV literature is mostly in vitro and animal work. It is reasonably consistent in what it reports about inflammatory signalling, and it is thin on the question of what happens in intact human systems: we found no published controlled human trials of KPV. The mechanistic account remains partially open. For a researcher, that combination means the compound is interesting to work with and premature to draw firm conclusions from.
The inflammatory pathway range at Peptx
Peptx supplies KPV, KPV in oral format and VIP within the inflammatory pathway research category, along with a single vial KPV format in the UK Express range.
Identity and purity of what we supply are measured and published in the COA library exactly as the issuing laboratory reported them. All material is supplied strictly for laboratory research use.
Related reading
- Inflammatory pathway research range
- BPC-157 vs TB-500: mechanisms compared
- Thymosin Alpha-1 and immune signalling
- Peptx COA library
- Research library
References
- Brzoska T, et al. (2008). Alpha-melanocyte-stimulating hormone and related tripeptides: biochemistry, antiinflammatory and protective effects in vitro and in vivo, and future perspectives for the treatment of immune-mediated inflammatory diseases. Endocrine Reviews. PubMed 18612139
- Catania A, et al. (2004). Targeting melanocortin receptors as a novel strategy to control inflammation. Pharmacological Reviews. PubMed 15001661
- Dalmasso G, et al. (2008). PepT1-mediated tripeptide KPV uptake reduces intestinal inflammation. Gastroenterology. PubMed 18061177
- Getting SJ, et al. (2003). Dissection of the anti-inflammatory effect of the core and C-terminal (KPV) alpha-melanocyte-stimulating hormone peptides. Journal of Pharmacology and Experimental Therapeutics. PubMed 12750433
- Hiltz ME, Lipton JM. (1989). Antiinflammatory activity of a COOH-terminal fragment of the neuropeptide alpha-MSH. FASEB Journal. PubMed 2550304
- Kannengiesser K, et al. (2008). Melanocortin-derived tripeptide KPV has anti-inflammatory potential in murine models of inflammatory bowel disease. Inflammatory Bowel Diseases. PubMed 18092346
- Land SC. (2012). Inhibition of cellular and systemic inflammation cues in human bronchial epithelial cells by melanocortin-related peptides: mechanism of KPV action and a role for MC3R agonists. International Journal of Physiology, Pathophysiology and Pharmacology. PubMed 22837805