KPV PEPTIDE 10MG/100MG VIAL

Main Research Findings

1) Treatment with KPV was found to reduce keratinocyte apoptosis induced by fine dust particles by regulating oxidative stress and NF-κB and MAPK pathways.

2) KPV has been shown to provide potential therapeutic benefits associated with inhibition of oxidative stress in order to restore damaged mucosal barriers.

Selected Data
1) The research team of Sung et al investigated the effects of the tripeptide KPV on PM10-induced cellular damage, inflammation, and apoptosis. For the purpose of this study, two types of human skin-related cell lines were used: immortalized human keratinocyte HaCaT cells and normal human dermal fibroblasts (NHDFs). Cells were maintained in Dulbecco’s modified Eagle’s medium supplemented with 10% FBS, streptomycin, and penicillin in standard incubator conditions at 37 °C with 5% CO₂. Before experimental treatments with PM10 and KPV, cells were serum-starved for 24 hours in FBS-free DMEM to synchronize conditions. To examine molecular pathways, cells were pre-treated with specific inhibitors 30 minutes before PM10 exposure. The inhibitors targeted ROS, ERK, p38 MAPK, NF-κB, and caspase-1. Importantly, the concentrations of these inhibitors were confirmed not to induce cytotoxicity when applied alone [1].
Cell viability was determined by two complementary assays. Proliferation of HaCaT cells was assessed using the EZ-CYTOX kit according to the manufacturer’s protocol. Following treatments, EZ-CYTOX reagent was added to 96-well plates, incubated for one hour, and absorbance was measured at 450 nm with a microplate reader. In parallel, a Live/Dead assay was conducted using a commercial kit from Abcam. This distinguished viable cells, which were stained green due to active esterases, from non-viable cells with damaged membranes, which were stained red. Ten random microscopic fields per coverslip were analyzed to calculate percentages of live and dead cells.
To assess oxidative stress, intracellular reactive oxygen species (ROS) were measured using the fluorescent probe CM-H2DCFDA. Treated cells were incubated with the probe and fluorescence was quantified using excitation/emission wavelengths of 485/535 nm, respectively. Inflammatory gene expression was studied with quantitative real-time PCR. RNA was extracted using the NucleoSpin RNA Plus kit, reverse-transcribed into cDNA, and amplified with specific primers for IL-1β, IL-6, TNF-α, and β-actin, which served as the internal control. Amplification was performed using the LightCycler 96 system under standard cycling conditions. Melting curve analysis was included to verify specificity of PCR products, and relative gene expression levels were analyzed using the delta CT method [1].
Western blotting was performed to measure protein expression and activation of signaling pathways. Proteins were extracted using RIPA buffer, quantified, separated by SDS-PAGE, and transferred to PVDF membranes. After blocking, membranes were incubated with primary antibodies overnight, followed by horseradish peroxidase-conjugated secondary antibodies. Bands were visualized with chemiluminescence and quantified using imaging software. Subcellular fractionation was also performed with a commercial kit to separate cytosolic and nuclear proteins, enabling analysis of NF-κB translocation [1].
The DNA binding activity of NF-κB p65 was determined using a transcription factor assay kit. Nuclear extracts were incubated with double-stranded DNA containing NF-κB response elements, and bound complexes were detected with specific antibodies. Absorbance was measured at 450 nm to quantify binding activity. Secreted cytokines were measured by ELISA. Supernatants from treated cells were centrifuged, filtered, and analyzed for IL-1β concentrations using a commercial kit according to the manufacturer’s instructions.
Immunofluorescence microscopy was also used to confirm protein localization and activation. Cells were fixed with paraformaldehyde, permeabilized with Triton X-100, and blocked with goat serum. They were incubated with primary antibodies followed by fluorescently labeled secondary antibodies and counterstained with DAPI for nuclei. Samples were visualized with a confocal microscope to examine NF-κB localization and other protein distributions [1].
To investigate energy metabolism, cellular ATP levels were determined using a luciferase-based ATP assay kit. Cells were lysed and incubated with a reaction mixture containing luciferin, luciferase, and dithiothreitol. Luminescence was measured with a microplate reader at excitation and emission wavelengths of 560 and 595 nm, respectively. To replicate the complexity of human skin, experiments were extended to a three-dimensional reconstructed skin model. This system consists of epidermal keratinocytes cultured atop dermal fibroblasts at the air-liquid interface, recapitulating the layered structure of human skin. The tissues were equilibrated before being exposed to KPV and PM10. In selected experiments, tissues were pre-treated with signaling inhibitors to examine molecular pathways.
In summary, the study employed a comprehensive suite of in vitro and ex vivo techniques, including proliferation and viability assays, ROS detection, qRT-PCR, western blotting, transcription factor assays, immunofluorescence, ELISA, ATP quantification, and 3D skin modeling. These methods were designed to evaluate how KPV modulates PM10-induced oxidative stress, inflammation, and apoptosis in skin-related cells and tissue models [1].
2) This study performed by Zhao et al describes the synthesis, characterization, and biological evaluation of a peptide-loaded hydrogel system designed to improve the therapeutic application of KPV in treating colonic inflammation. A range of materials and procedures were employed to develop the formulation, investigate its structural and functional properties, and assess its efficacy in both in vitro and in vivo models of colitis [2].
KPV was combined with γ-polyglutamic acid (PGA), which was chemically modified to allow hydrogel formation. Various reagents, including carbodiimide (EDC), N-hydroxysuccinimide (NHS), and 3-maleimidopropionic acid (MA), were used to prepare functionalized intermediates. Fetal bovine serum, cell culture media, and other standard biochemical reagents supported the biological assays. A cysteine-modified PGA (PGA-SH) was synthesized following a previously reported method to introduce thiol groups, which later facilitated hydrogel cross-linking.
The synthesis of maleimide-functionalized PGA (PGA-MAL) was achieved through a two-step chemical reaction. First, MA was reacted with ethylenediamine in the presence of EDC/NHS to yield an amino-terminated intermediate. Separately, PGA was dissolved in a buffer and its side-chain carboxyl groups were activated using EDC/NHS. The amino-terminated intermediate was then coupled to the activated PGA, producing PGA-MAL. The product was purified through dialysis and freeze-drying. Structural characterization was performed by Fourier-transform infrared spectroscopy and proton nuclear magnetic resonance, which confirmed successful grafting of the MA groups onto the polymer backbone [2].
Hydrogels were formed by combining solutions of PGA-MAL and PGA-SH at equal concentrations. These reacted via thiol–maleimide chemistry to create a cross-linked polymer network known as PMSP hydrogel. To prepare drug-loaded hydrogels, KPV was dissolved in the polymer solution before cross-linking. A control hydrogel without maleimide groups was also prepared, as well as a poloxamer-based formulation for comparison.
Adhesive properties were assessed through shear tests using gelatin substrates of varying charges to mimic mucosal surfaces. PMSP hydrogels displayed strong bio-adhesive forces across different conditions, outperforming poloxamer gels. Adhesion to fresh rat colon tissues was also confirmed, demonstrating their potential to localize in the gastrointestinal tract [2].
The stability and erosion resistance of the hydrogels were tested in simulated intestinal fluids at multiple pH values. PMSP hydrogels showed superior resistance to erosion compared with control hydrogels. Release experiments demonstrated sustained KPV delivery over time, with release profiles dependent on environmental pH. The protective effect of the hydrogel matrix on peptide stability was confirmed by accelerated stability testing at elevated temperatures. KPV entrapped in the hydrogel retained bioactivity in cell proliferation and migration assays, while free KPV solution rapidly lost activity under similar conditions [2].
For in vivo testing, a rat model of colitis was induced using 2,4,6-trinitrobenzenesulfonic acid (TNBS). Animals were monitored for weight changes, disease activity index scores, and colon ulceration to confirm disease induction. Targeting experiments demonstrated preferential adhesion and retention of KPV-loaded hydrogels in the inflamed colon, both in ex vivo and live animal studies. Fluorescently labeled KPV facilitated visualization, confirming that the hydrogel localized effectively at the diseased sites compared with neutral poloxamer-based gels.
Therapeutic studies were then conducted in TNBS-induced colitis rats. Animals were divided into groups receiving different treatments, including saline control, 5-aminosalicylic acid (5-ASA), free KPV solution, blank PMSP hydrogel, KPV-loaded PMSP hydrogel, and KPV-loaded poloxamer hydrogel. Treatments were administered rectally every other day, and disease progression was monitored through clinical scores, endoscopic imaging, and colon length measurements. The PMSP-KPV formulation showed the most pronounced therapeutic benefit, improving body weight recovery, lowering disease scores, and reducing mucosal damage [2].
The protective effects of PMSP-KPV on barrier function were confirmed by reduced intestinal permeability to fluorescent dextran in treated animals. Histological analyses, including hematoxylin and eosin, Alcian blue, Masson trichrome, and Sirius red staining, revealed improved mucosal architecture, reduced fibrosis, and restored goblet cell populations in treated groups. Immunohistochemistry and immunofluorescence assays further demonstrated reduced expression of pro-inflammatory cytokines such as IL-1β, TNF-α, and IL-6, along with enhanced levels of anti-inflammatory cytokines IL-10 and IL-13. Collagen I, collagen III, and other fibrotic markers were decreased, while epithelial barrier proteins such as ZO-1, occludin, and claudin-5 were preserved [2].
At the molecular level, cytokine and oxidative stress markers in colon tissues were quantified. PMSP-KPV treatment reduced ROS generation, malondialdehyde levels, and myeloperoxidase activity, while increasing antioxidant enzyme activity. Western blotting confirmed preservation of tight junction proteins, consistent with barrier protection. Finally, microbiome analysis revealed that PMSP-KPV treatment modulated gut microbial composition. DNA was extracted from fecal samples, sequenced, and analyzed for diversity metrics. The treatment improved alpha and beta diversity and shifted microbial community composition toward a healthier profile, indicating that benefits extended beyond local anti-inflammatory effects to include broader impacts on gut ecology.
In summary, this extensive series of experiments demonstrated that PMSP hydrogels provide a stable, adhesive, and erosion-resistant delivery platform for KPV. By sustaining peptide release and targeting inflamed colonic tissue, the formulation significantly improved outcomes in a preclinical model of colitis. The therapeutic effects were mediated by reduction of inflammatory cytokines, preservation of epithelial barrier integrity, suppression of oxidative stress, and restoration of microbial balance. These findings highlight PMSP-KPV hydrogels as a promising strategy for the treatment of inflammatory bowel disease [2].

Discussion
1) The study performed by Sung et al explored the protective role of the peptide KPV against skin cell injury and inflammation triggered by fine dust particles (PM10), which are defined as particulate matter with an aerodynamic diameter of less than 10 μm. Initial experiments using HaCaT keratinocytes demonstrated that PM10 exposure led to dose-dependent cytotoxicity, with concentrations between 100 and 200 μg/mL significantly decreasing cell viability. A time-dependent decline in survival was also noted, confirming that PM10 effectively induced cellular damage [1].
When KPV was administered alongside PM10, the peptide significantly rescued cell viability, with nearly complete recovery observed at concentrations of 100 μg/mL or greater. In addition, PM10 strongly upregulated the pro-inflammatory cytokine IL-1β at both the mRNA and protein levels, while having minimal effects on TNF-α and IL-6. KPV treatment markedly suppressed IL-1β expression and secretion in both keratinocytes and normal human dermal fibroblasts, suggesting that its protective effects extend across multiple skin cell types. Comparative experiments with epigallocatechin gallate (EGCG), a well-known antioxidant compound from green tea, showed that EGCG and KPV provided similar protection against PM10-induced cell death and inflammation, highlighting KPV’s therapeutic potential [1].
The antioxidant properties of KPV were then examined in detail. Exposure to PM10 triggered a rapid increase in intracellular ROS within minutes, initiating pathways of apoptosis and inflammation. Treatment with KPV effectively suppressed this ROS surge, as confirmed by fluorescence staining assays. Further experiments using N-acetylcysteine (NAC), a standard antioxidant, revealed that reducing ROS also lessened PM10-induced cytotoxicity and IL-1β production, indicating that KPV’s beneficial actions were linked to its ability to counter oxidative stress.
Building on these findings, the researchers analyzed how KPV influenced downstream signaling cascades activated by ROS, particularly the MAPK pathways. PM10 exposure enhanced phosphorylation of ERK and p38 MAPK, both of which are central mediators of cell death and inflammatory signaling, but it had little effect on JNK activation. KPV treatment substantially reduced phosphorylation of ERK and p38 MAPK, similar to NAC. When chemical inhibitors targeting ERK and p38 were used, cell viability improved and IL-1β levels decreased, confirming that ROS-driven MAPK activation was a crucial step in PM10-induced cellular injury. KPV’s ability to block these phosphorylation events highlighted its role as a modulator of MAPK-related oxidative signaling [1].
Attention then turned to NF-κB, a major transcription factor that orchestrates apoptosis and inflammatory gene expression. PM10 triggered phosphorylation and degradation of IκBα, enabling NF-κB activation and translocation into the nucleus within one hour. KPV treatment prevented these changes, lowering NF-κB phosphorylation and reducing its DNA binding activity. The ERK and p38 inhibitors produced similar effects, underscoring the upstream link between ROS/MAPK signaling and NF-κB activation. TNF-α, a known activator of NF-κB, was used as a positive control and produced comparable increases in nuclear NF-κB activity, further validating the pathway. KPV not only suppressed phosphorylation events but also prevented the nuclear translocation of phosphorylated NF-κB, as confirmed by immunofluorescence. Inhibiting NF-κB with Bay 11–7082 also decreased PM10-induced cell death and IL-1β secretion, demonstrating that NF-κB is a central driver of the observed inflammatory cytotoxicity, and KPV’s protective effects rely heavily on its suppression of this pathway [1].
The role of KPV in preventing apoptosis was further explored. PM10 exposure increased the expression of the pro-apoptotic protein Bax, decreased the anti-apoptotic protein Bcl-2, and enhanced cleavage of caspase-3, confirming activation of the mitochondrial apoptotic pathway. Treatment with KPV restored these protein levels, preventing the shift toward apoptosis. KPV also preserved intracellular ATP levels, which are typically depleted during mitochondrial stress. In addition, a live-cell imaging assay confirmed that PM10 greatly increased the number of dead cells, while KPV, NAC, and inhibitors of ERK, p38, and NF-κB all significantly reduced cytotoxicity. These results reinforced the conclusion that KPV effectively disrupts the apoptotic signaling cascade initiated by PM10.
Beyond apoptosis, PM10 exposure also induced pyroptosis, a form of inflammatory cell death characterized by caspase-1 activation. Elevated levels of cleaved caspase-1 were observed after 12 hours of exposure. KPV and NAC significantly reduced caspase-1 activation, and inhibition of caspase-1 with VX-765 led to reduced IL-1β secretion, establishing a link between oxidative stress, caspase-1 activity, and inflammatory cytokine release. These findings demonstrated that KPV can block not only apoptotic but also pyroptotic pathways triggered by fine dust [1].
Finally, KPV’s effects were validated in a three-dimensional reconstructed human skin model that simulates both the epidermal and dermal layers. PM10 exposure significantly decreased cell viability and increased IL-1β secretion in this model, mirroring the results observed in cell culture. Co-treatment with KPV restored viability and reduced cytokine release. Similar benefits were observed with inhibitors of ROS, ERK, p38, NF-κB, and caspase-1, supporting the conclusion that KPV’s protective effects involve modulation of these interconnected signaling pathways [1].
Overall, the study demonstrated that KPV provides protection against PM10-induced cytotoxicity in keratinocytes, fibroblasts, and reconstructed human skin. Its mechanisms of action include scavenging ROS, suppressing MAPK and NF-κB signaling, preventing mitochondrial apoptosis, and blocking caspase-1-mediated pyroptosis. These findings establish KPV as a potent pharmacological candidate for mitigating environmental pollutant-induced skin damage by preserving cellular viability and reducing inflammation [1].
2) The experiment completed by researchers Zhao et al developed and evaluated a novel hydrogel system (PMSP) designed for targeted delivery of the therapeutic tripeptide KPV to the inflamed colon. The goal was to create a biocompatible, adhesive, and pH-responsive material that could improve drug retention, stabilize bioactivity, and enhance therapeutic outcomes in ulcerative colitis (UC) [2].
PMSP hydrogels exhibited erosion behavior that was highly sensitive to pH. At an acidic pH of 5.5, the hydrogels degraded slowly, ensuring prolonged local retention. In contrast, at a physiological pH of 7.4, erosion was rapid, allowing clearance from non-inflamed tissue. This selective stability was attributed to the greater resistance of thioether crosslinks in acidic conditions and electrostatic repulsion between ionized carboxyl groups at neutral pH. Drug release mirrored this pattern as KPV was released slowly at pH 5.5 but rapidly at pH 7.4, enabling sustained delivery at sites of inflammation.
Because inflamed mucosa is enriched with positively charged proteins, the negatively charged PMSP hydrogels showed strong electrostatic adhesion. Compared to a neutral control hydrogel, PMSP hydrogels adhere more strongly to positively charged substrates and to inflamed colon tissue, both in vitro and in vivo. Additional adhesion likely arose from thiol-disulfide bonding with mucosal cysteine residues. PMSP-10% displayed the highest adhesive force and was selected for animal studies [2].
Free KPV is prone to degradation under stress. Encapsulation in PMSP hydrogels protected KPV against heat-induced inactivation, retaining nearly 80% of activity after heating compared with <40% in free solution. Bioassays in hydrogen peroxide-damaged Caco-2 cells showed that PMSP-KPV preserved proliferative and migratory activity, confirming that the hydrogel enhanced stability without compromising function. In TNBS-induced colitis rats, fluorescently labeled PMSP-KPV hydrogels demonstrated strong and prolonged retention at inflamed sites compared with free KPV or P407 hydrogels. The PMSP system adhered preferentially to ulcerated mucosa rather than healthy colon, highlighting its inflammation-targeting capability through both electrostatic adhesion and pH-dependent erosion [2].
Treatment with PMSP-KPV significantly improved disease activity in UC rats. Animals showed recovery in body weight, decreased disease activity index, and restoration of colon length and morphology. Colonoscopy confirmed reduced bleeding and ulceration, while histology revealed restored epithelial integrity, reduced neutrophil infiltration, and decreased submucosal edema. PMSP-KPV outperformed both free KPV and comparator treatments such as 5-ASA and P407-KPV hydrogels.
PMSP-KPV treatment effectively repaired crypt architecture, increased goblet cell numbers, and restored production of protective mucins. Functional goblet cells were well organized, resembling those in healthy tissue. The hydrogel also improved collagen composition, raising the ratio of type III to type I collagen, thereby reducing fibrosis risk. Importantly, PMSP-KPV upregulated tight junction proteins including ZO-1, claudin-5, occludin-1, and β-catenin, indicating restoration of epithelial barrier integrity [2].
Immunohistochemistry and ELISA showed that PMSP-KPV suppressed proinflammatory cytokines IL-1β, IL-6, and TNF-α while enhancing anti-inflammatory IL-10. It also reduced expression of profibrotic markers IL-13, MCP-1, TGF-β1, and α-SMA, effectively alleviating both inflammation and fibrotic remodeling. Microbiome analysis revealed that colitis disrupted microbial diversity and abundance. PMSP-KPV treatment broadened the rank-abundance curve and restored species uniformity, closely resembling the healthy control group. This suggests the KPV hydrogel not only alleviates colitis symptoms but also contributes to rebalancing gut flora [2].

Figure 1: Changes in the levels of proinflammatory cytokines, anti-inflammatory cytokines, and profibrotic markers across the experimental treatment groups.

Disclaimer

**LAB USE ONLY**
*This information is for educational purposes only and does not constitute medical advice. THE PRODUCTS DESCRIBED HEREIN ARE FOR RESEARCH USE ONLY. All clinical research must be conducted with oversight from the appropriate Institutional Review Board (IRB). All preclinical research must be conducted with oversight from the appropriate Institutional Animal Care and Use Committee (IACUC) following the guidelines of the Animal Welfare Act (AWA).

Citations

[1] Sung J, Ju SY, Park S, Jung WK, Je JY, Lee SJ. Lysine-Proline-Valine peptide mitigates fine dust-induced keratinocyte apoptosis and inflammation by regulating oxidative stress and modulating the MAPK/NF-κB pathway. Tissue Cell. 2025;95:102837. doi:10.1016/j.tice.2025.102837

[2] Zhao Y, Xue P, Lin G, et al. A KPV-binding double-network hydrogel restores gut mucosal barrier in an inflamed colon. Acta Biomater. 2022;143:233-252. doi:10.1016/j.actbio.2022.02.039

PEPTIDES PREFER THE COLD
Keep peptide vials refrigerated at all times to reduce peptide bond breakdown. DO NOT FREEZE. Most peptides, especially shorter ones, can be preserved for weeks if careful.
Always swab the top of the vial with an alcohol wipe, rubbing alcohol or 95% ethanol before use.
Before drawing solution from any dissolved peptide vial, fill the pin with air to the same measurement you will be filling with solution, ie. if you plan to take 0.1 ml, first fill the pin with 0.1ml of air, push the air into the vial, and then draw the peptide back up to the 0.1 ml marker. Doing so will maintain even pressure in the vial. Always remember to remove air bubbles from the pin by flicking it gently, pin side up, and pushing bubbles out. In addition, push out a tiny amount of solution to ensure there is no air left in the metal tip.

ONLY MIX WITH STERILE BACTERIOSTATIC WATER
The purity and sterility of bacteriostatic water are essential to prevent contamination and to preserve the shelf-life of dissolved peptides.
Push the pin through the rubber stopper at a slight angle, so that you inject the bacteriostatic water toward the inside wall of the vial, not directly onto the powder.
Lyophilized peptide should be stored at -20°C (freezer), and the reconstituted peptide solution at 4°C (refrigerated). Do not freeze once reconstituted.

NEVER SHAKE A VIAL TO MIX.
Air bubbles are unfavorable to the stability of proteins.

KPV is sold for laboratory research use only. Terms of sale apply. Not for human consumption, nor medical, veterinary, or household uses. Please familiarize yourself with our Terms & Conditions prior to ordering.