GHK-Cu

Golgi-targeted copper delivery strategy via enhancing copper-dependent proteins' activity for fascia regeneration.

Rui Wang, Yiru Xu, Qimanguli Saiding +5 more

Copper-dependent proteins (such as lysyl oxidase, LOX) require copper acquisition within the Golgi apparatus to achieve enzymatic activation, and insufficient activation of these proteins is a key factor limiting fascia regeneration. To address this issue, this study, for the first time, proposes and validates a Golgi-targeted copper delivery system (LNP-ATOX1/GHK-Cu@PCL-GelMA). In this system, GHK-Cu serves as a stable copper source to provide a sustained release of Cu ions for cellular uptake, while lipid nanoparticles (LNPs) are used to deliver mRNA encoding the copper chaperone ATOX1. Upregulation of ATOX1 facilitates the transport of copper into the Golgi apparatus via ATP7A/B, thereby enhancing the activity of copper-dependent proteins. In addition, ATOX1 promotes the copper-dependent translocation of ATP7A and Rac1 to the plasma membrane, synergistically accelerating neovascularization. In vitro studies demonstrated that this material system significantly increased copper accumulation within the Golgi apparatus, elevated LOX activity to 1.78 times that of the control group, and enhanced angiogenic capacity. In a rabbit fascia defect model, this strategy effectively promoted collagen alignment and neovascularization, improving extracellular matrix reconstruction and facilitating fascia regeneration. In conclusion, this work establishes a novel Golgi-targeted copper delivery strategy, providing a practical therapeutic approach for regenerative disorders caused by insufficient activation of copper-dependent proteins, such as fascia defects.

An injectable hydroxyapatite microsphere filler loaded with GHK-Cu tripeptide for anti-Inflammatory and antioxidant.

Die Hu, Xuexun Zhang, Shiwen Gong +7 more

With the wide application of soft tissue fillers, implant material-induced inflammatory reactions have become a key factor affecting the therapeutic efficacy. This study developed an injectable filler with enhanced anti-inflammatory and antioxidant effects by adsorbing glycyl-L-histidyl-L-lysine copper complex (GHK-Cu) onto hydroxyapatite microspheres (HAPs), marking the first combination of HAPs and GHK-Cu to address inflammation caused by soft tissue fillers. GHK-Cu was successfully loaded onto HAPs by electrostatic adsorption. HAPs were then mixed with carboxymethyl cellulose (CMC), glycerol (GLY), and water to form GHK-Cu@CMHA gel. The study focus on the effective combination of HAPs as a carrier for sustained GHK-Cu delivery and the anti-inflammatory properties of GHK-Cu. GHK-Cu@CMHA exhibits sustained release properties for 7 days, which ensures prolonged therapeutic effects, minimizes peptide waste and reduces injection frequency, with good flowability and injectability. In the model of LPS-induced inflammation model in vivo and in vitro, GHK-Cu@CMHA gel reduced levels of inflammatory factors and Reactive oxygen species (ROS) levels decreased, while superoxide dismutase (SOD) activity was enhanced. In this process, H&E staining and Masson staining revealed significant collagen deposition. These findings further confirm that GHK-Cu@CMHA is a novel injectable soft tissue filler with good anti-inflammatory and antioxidant properties, which holds well potential for inflammation inhibition.

Self-Assembled Peptide-Gold Nanoparticle 1D Nanohybrids Functionalized with GHK Tripeptide for Enhanced Wound-Healing and Photothermal Therapy.

Nayeong Jeon, Leeseo Kim, Seong Gyu Choi +5 more

Glycyl-l-histidyl-l-lysine (GHK) tripeptides are known for their remarkable therapeutic potential, including wound-healing, anti-inflammatory activity, and cellular regeneration. However, their clinical application has been significantly hindered by poor biological stability and limited efficacy in a physiological medium. In this study, we introduce a sophisticated approach to overcome these limitations by developing supramolecular peptide nanofiber-gold (Au) nanoparticle (NP) hybrids functionalized with GHK tripeptides. By strategically manipulating peptide self-assembly and NP integration, we demonstrated a useful platform that enhances both therapeutic efficacy and material stability. Our methodology involves the precise engineering of 9-fluorenylmethoxycarbonyl-diphenylalanine scaffolds with GHK and KHG tripeptides, enabling robust nanofibril formation through π-π stacking and hydrogen bonding. Critically, we discovered that the specific amino acid sequence significantly influences the surface exposure of lysine, directly impacting the nanohybrid's wound-healing capabilities. The resultant nanohybrids exhibit exceptional characteristics: Au NPs are spatially confined within the peptide nanofibers, achieving a remarkably uniform size distribution of approximately 3 nm. These nanohybrids demonstrate superior near-infrared (NIR) light absorption and photothermal conversion efficiency, enabling effective eradication of cancer cells and organoids killing under NIR irradiation. This dual-functional nanohybrid integrates biocompatible and enzymatically degradable peptide scaffolds to achieve synergistic wound-healing and cancer-killing effects. By mitigating the cytotoxicity and biodegradability issues associated with conventional photothermal agents, our system provides a promising strategy to improve postoperative cancer therapy and promote tissue regeneration. This work highlights the potential of peptide-inorganic nanohybrids in advancing multifunctional therapeutic platforms for cancer treatment and tissue repair.

Are We Ready to Measure Skin Permeation of Modern Antiaging GHK-Cu Tripeptide Encapsulated in Liposomes?

Karolina Ogórek, Kinga Nowak, Emilia Wadych +3 more

Cosmetically active compounds (CACs), both of lipophilic and hydrophilic origin, have difficulty reaching the deeper layers of the skin, and this shortcoming significantly reduces their efficacy. One such CAC that occurs naturally in the human body and displays many beneficial properties (via reducing fine lines and wrinkles, tightening skin, improving its elasticity, etc.) is the glycyl-L-histidyl-L-lysine tripeptide complex of copper (GHK-Cu). GHK-Cu is a fairly hydrophilic compound with limited permeation through the lipophilic stratum corneum. On the other hand, liposomes capable of encapsulating GHK-Cu may improve its permeation potential. The present review discusses various issues related to obtaining insight into the permeation of CACs through the skin. Methods for studying the transport of CACs encapsulated by liposomes and free GHK-Cu across the skin barrier are summarized. An analysis of the literature data reveals that the transport of liposomes containing GHK-Cu received little attention. This research gap gives an impetus to the methodological developments for assessing the effect of liposomes on GHK-Cu transportation and trafficking.

Topically applied GHK as an anti-wrinkle peptide: Advantages, problems and prospective.

Seyedeh Maryam Mortazavi, Seyyed Ali Mohammadi Vadoud, Hamid Reza Moghimi

Peptides are promising and attractive anti-wrinkle active ingredients, amongst which glycyl-histidyl-lysine peptide (GHK) is one of the most broadly promoted peptide for topical application. This simple sequence of amino acid residues not only has the capability of tissue regeneration and the enhancement of collagen and glycosaminoglycans synthesis but also is able to increase nerve outgrowth and angiogenesis. Consequently, GHK has several properties, from wound healing to prevention/reduction wrinkles. GHK-Cu and Pal-GHK are metal complex and palmitoylated derivatives of GHK, respectively. Although GHK-Cu and Pal-GHK are widely used in anti-wrinkle products available on the cosmetic market, the published information on their skin permeability, effectiveness, physicochemical properties and so on is insufficient.

Copper Complexes with New Glycyl-l-histidyl-l-lysine-Hyaluronan Conjugates Show Antioxidant Properties and Osteogenic and Angiogenic Synergistic Effects.

Valentina Greco, Valeria Lanza, Barbara Tomasello +4 more

In recent years, hyaluronic acid (HA) and the natural tripeptide glycyl-l-histidyl-l-lysine (GHK), especially its copper(II) complex (GHK-Cu), individually have been shown to exert helpful properties for bone protection and regeneration. However, they are not strong enough to handle oxidative stress, hydrolytic attack, or environmental conditions. Being aware that conjugation chemistry has recently emerged as an appealing approach for generating new molecular entities capable of preserving the molecular integrity of their moieties or delaying their degradation, herein we present the synthesis of conjugates of HA with GHK (GHK-HA), at different loadings of the tripeptide. GHK-HA binds copper(II) ions and potentiates the chemical and biological properties of the two components in in vitro assays. The results highlight copper's role in promoting the expression and release of certain trophic, angiogenic, and osteogenic factors, including brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF), as well as bone morphogenetic protein-2 (BMP-2). The protective and regenerative activities of the metal ion are related to the translocation of its intracellular chaperones Copper Chaperone for Superoxide Dismutase (CCS) and Antioxidant-1 (Atox1) to the nucleus where they act as transcription factors.

Food-Derived Tripeptide-Copper Self-Healing Hydrogel for Infected Wound Healing.

Han Chen, Pu Yang, Ping Xue +5 more

The field of infected wound management continues to face challenges, and traditional methods used to cope with wounds include debridement, gauze coverage, medication, and others. Currently, synthetic and natural biomaterials are readily available today, enabling the creation of new wound dressings that substantially enhance wound healing. Considerable attention is being paid to hydrogels based on natural materials, which have good biocompatibility and degradability properties, while exhibiting higher similarity to natural extracellular matrix as compared to synthetic materials. In this study, we extracted the active ingredients of oxidized konjac glucomannan (OKGM) and fresh egg white (EW) from 2 foods, konjac, and egg, respectively, and formed a self-repairing hydrogel based on the cross-linking of a Schiff base. Subsequently, a natural active peptide, glycyl-l-histidyl-l-lysine-Cu (GHK-Cu), was loaded, and an all-natural composite hydrogel dressing, EW/OKGM@GHK-Cu (GEK), was developed. The GEK hydrogel, exhibiting both antibacterial and anti-inflammatory properties, plays a hemostatic role by adhering to tissues and promoting neovascularization and serves as an optimal dressing for skin regeneration. Taken together, GEK hydrogel dressings derived from natural food sources therefore constitute an efficient and cost-effective strategy for managing infected wound healing and have significant potential for clinical application and transformation.

Novel Applications of CE-ICP-MS/MS: Monitoring of Antiaging GHK-Cu Cosmetic Component Encapsulation in Liposomes.

Joanna Zajda, Emilia Wadych, Karolina Ogórek +2 more

The hyphenation of the separation technique with the high-sensitive mass spectrometry detection is one of the driving forces of modern analysis enabling measurements in complex matrices. In particular, capillary electrophoresis coupled to inductively coupled plasma tandem mass spectrometry allows for speciation analysis of selected analytes with a superior resolution. The mild, physiological-friendly conditions of this separation technique offer the unique advantage of analyzing chemical entities in their intact form, which has been successfully exploited in various areas. Herein, we report the pioneering application of such a hyphenated technique in the cosmetic field to investigate the encapsulation of copper tripeptide complex (GHK-Cu) in liposomes. By monitoring copper and phosphorus signals, the formation of liposomes via a simple ethanol injection method was confirmed, and the concentration of GHK-Cu in the liposomes was assessed. The application of coupling of capillary electrophoresis with inductively coupled plasma tandem mass spectrometry (CE-ICP-MS/MS) in cosmetic studies could lead to the development of diverse liposomal formulations with preferential properties and expand their accessibility.

Palmitoyl copper peptide and acetyl tyrosine complex enhances melanin production in both A375 and B16 cell lines.

Minhua Hong, Yingyue Gui, Jiayao Xu +8 more

Copper peptide, a low molecular weight peptide composed of glycyl-L-histidyl-l-lysine-copper, possesses anti-aging, anti-inflammatory, and wound healing properties. In this study, we investigated the effects of a combination agent CP-AcT, composed of palmitoyl copper peptide (pal-GHK-Cu) and acetyl tyrosine (N-Acetyl-l-tyrosine), on melanin production in the human malignant melanoma cell line A375 and the mouse melanoma cell line B16. Firstly, the cytotoxicity of CP-AcT at various concentrations (0-8 μg/mL) on HaCat, HFF, A375, and B16 cells was evaluated. Subsequently, the effects of the CP-AcT on tyrosinase activity both extracellular and intracellularly, as well as on melanin production in two melanoma cell lines, were evaluated under conditions that did not compromise cell viability. Additionally, quantitative gene plex (QGP) combined with branched DNA (bDNA) technology was used to analyze the effects of CP-AcT on the expression of melanin-related genes in A375 cells, with a focus on five specific genes. Finally, the effects of the CP-AcT on the expression of three proteins involved in the biosynthesis pathway of melanin: tyrosinase (TYR), dopachrome tautomerase (DCT), and endothelin 3 (EDN3) were analyzed. The results indicate that the complex CP-AcT effectively promotes melanin production in both types of melanoma cells.

The glycyl-l-histidyl-l-lysine-Cu2+ tripeptide complex attenuates lung inflammation and fibrosis in silicosis by targeting peroxiredoxin 6.

Yiding Bian, Mingming Deng, Jia Liu +8 more

Silicosis is the most common type of pneumoconiosis, having a high incidence in workers chronically exposed to crystalline silica (CS). No specific medication exists for this condition. GHK, a tripeptide naturally occurring in human blood and urine, has antioxidant effects. We aimed to investigate the therapeutic effect of GHK-Cu on silicosis and its potential underlying molecular mechanism. An experimental silicosis mouse model was established to observe the effects of GHK-Cu on lung inflammation and fibrosis. Moreover, the effects of GHK-Cu on the alveolar macrophages (AM) were examined using the RAW264.7 cell line. Its molecular target, peroxiredoxin 6 (PRDX6), has been identified, and GHK-Cu can bind to PRDX6, thus attenuating lung inflammation and fibrosis in silicosis mice without significant systemic toxicity. These effects were partly related to the inhibition of the CS-induced oxidative stress in AM induced by GHK-Cu. Thus, our results suggest that GHK-Cu acts as a potential drug by attenuating alveolar macrophage oxidative stress. This, in turn, attenuates the progression of pulmonary inflammation and fibrosis, which provides a reference for the treatment of silicosis.

Glycyl-l-histidyl-l-lysine prevents copper- and zinc-induced protein aggregation and central nervous system cell death in vitro.

Jin-Hong Min, Heela Sarlus, Robert A Harris

Common features of neurodegenerative diseases are oxidative and inflammatory imbalances as well as the misfolding of proteins. An excess of free metal ions can be pathological and contribute to cell death, but only copper and zinc strongly promote protein aggregation. Herein we demonstrate that the endogenous copper-binding tripeptide glycyl-l-histidyl-l-lysine (GHK) has the ability to bind to and reduce copper redox activity and to prevent copper- and zinc-induced cell death in vitro. In addition, GHK prevents copper- and zinc-induced bovine serum albumin aggregation and reverses aggregation through resolubilizing the protein. We further demonstrate the enhanced toxicity of copper during inflammation and the ability of GHK to attenuate this toxicity. Finally, we investigated the effects of copper on enhancing paraquat toxicity and report a protective effect of GHK. We therefore conclude that GHK has potential as a cytoprotective compound with regard to copper and zinc toxicity, with positive effects on protein solubility and aggregation that warrant further investigation in the treatment of neurodegenerative diseases.

The potential of GHK as an anti-aging peptide.

Yan Dou, Amanda Lee, Lida Zhu +2 more

GHK (glycyl-L-histidyl-L-lysine) is a naturally occurring peptide found in human serum with levels averaging 200 ng/ml at age 20 but declining to an average of 80 ng/ml by age 60. The molecule has a very high affinity for copper and forms the chelate GHK-Cu. The peptide as well as its Cu (II) chelate have anti-inflammatory and tissue remodeling properties. GHK-Cu has been shown to promote skin remodeling, wound healing and regeneration, and has prominent antioxidant and anti-inflammatory effects in in vitro and in vivo studies. In addition, preliminary observations suggest GHK can partially reverse cognitive impairment in aging mice by targeting anti-inflammatory and epigenetic pathways. The evidence as presented provides the rationale to further investigate this naturally occurring peptide in preclinical and clinical aging studies.

Rigid-flexible nanocarriers loaded with active peptides for antioxidant and anti-inflammatory applications in skin.

Yan Wang, Jialiang Lin, Zihao Yu +3 more

Peptides are recognized as highly effective and safe bioactive ingredients. However, t their practical application is limited and hampered by harsh conditions for practical drug delivery. Hence, a novel peptide nanocarrier of copper peptide (GHK-Cu) encapsulation developed by liposome technology combined with the classical Chinese concept of rigidity and flexibility. Different polyols were selected as modification ligands for phospholipid bilayers to construct a nano drug-carrying system with high loading rate, good stability and biocompatibility. In vitro, this complex not only significantly retarded the release ability of copper peptides, but also enabled copper peptides to be effectively resistant to enzymatic degradation. Furthermore, cellular experiments showed that this system mainly regulates Nrf2, SIRT1, and PEG2/COX-2-related signaling pathways, thus effectively counteracting cellular inflammation, senescence, and apoptosis from oxidative damage. Interestingly, a green, non-toxic, efficient and convenient antioxidant system was developed for the prevention and deceleration of skin aging.

Design, synthesis, and characterization of type I collagen mimetic peptides.

Ntlama Lesotho, Thabo Peme, Maya Makatini

The current wound-healing collagen mimetic peptides (CMPs) have limitations such as poor membrane permeability and protease susceptibility. Herein, the solid-phase peptide synthesis of CMPs containing the integrin binding motif GFOGER is reported. The peptide sequences also consist of lipophilic moieties (adamantane and palmitic acid) for improved membrane permeability and different collagen-inducing tripeptides, namely, Thr-Thr-Lys (TTK), Gly-His-Lys (GHK), Gln-Pro-Arg (QPR), and Glu-Glu-Met (EEM). The synthesized peptides were successfully characterized and purified using liquid chromatography-mass spectrometry and preparative high-performance liquid chromatography techniques, respectively. The palmitic acid moiety increased the hydrophobic nature of the peptides, and they were retained longer on the stationary material of the reverse phase C-18 column. The three-dimensional parallel-strand helical structure of peptide DGD-GG-GFOGER-GG-TTK-palmitate was obtained using nuclear magnetic resonance spectroscopy and circular dichroism. The synthesized peptides have the desired helical structure, which can promote integrin binding.

Thermodynamically stable ionic liquid microemulsions pioneer pathways for topical delivery and peptide application.

Tianqi Liu, Ying Liu, Xiaoyu Zhao +7 more

Copper peptides (GHK-Cu) are a powerful hair growth promoter with minimal side effects when compared with minoxidil and finasteride; however, challenges in delivering GHK-Cu topically limits their non-invasive applications. Using theoretical calculations and pseudo-ternary phase diagrams, we designed and constructed a thermodynamically stable ionic liquid (IL)-based microemulsion (IL-M), which integrates the high drug solubility of ILs and high skin permeability of microemulsions, thus improving the local delivery of copper peptides by approximately three-fold while retaining their biological function. Experiments in mice validated the effectiveness of our proposed IL-M system. Furthermore, the exact effects of the IL-M system on the expression of growth factors, such as vascular endothelial growth factor, were revealed, and it was found that microemulsion increased the activation of the Wnt/β-catenin signaling pathway, which includes factors involved in hair growth regulation. Overall, the safe and non-invasive IL microemulsion system developed in this study has great potential for the clinical treatment of hair loss.

In situ photo-crosslinkable hyaluronic acid-based hydrogel embedded with GHK peptide nanofibers for bioactive wound healing.

Seohui Lee, Sang Min Lee, Sang Hyun Lee +13 more

A versatile hydrogel was developed for enhancing bioactive wound healing by introducing the amphiphilic GHK peptide (GHK-C16) into a photo-crosslinkable tyramine-modified hyaluronic acid (HA-Ty). GHK-C16 self-assembled into GHK nanofibers (GHK NF) in HA-Ty solution, which underwent in situ gelation after the wound area was filled with precursor solution. Blue light irradiation (460-490 nm), with riboflavin phosphate as a photoinitiator, was used to trigger crosslinking, which enhanced the stability of the highly degradable hyaluronic acid and enabled sustained release of the nanostructured GHK derivatives. The hydrogels provided a microenvironment that promoted the proliferation of dermal fibroblasts and the activation of cytokines, leading to reduced inflammation and increased collagen expression during wound healing. The complexation of Cu2+ into GHK nanofibers resulted in superior wound healing capabilities compared with non-lipidated GHK peptide with a comparable level of growth factor (EGF). Additionally, nanostructured Cu-GHK improved angiogenesis through vascular endothelial growth factor (VEGF) activation, which exerted a synergistic therapeutic effect. Furthermore, in vivo wound healing experiments revealed that the Cu-GHK NF/HA-Ty hydrogel accelerated wound healing through densely packed remodeled collagen in the dermis and promoting the growth of denser fibroblasts. HA-Ty hydrogels incorporating GHK NF also possessed improved mechanical properties and a faster wound healing rate, making them suitable for advanced bioactive wound healing applications. STATEMENT OF SIGNIFICANCE: By combining photo-crosslinkable tyramine-modified hyaluronic acid with self-assembled Cu-GHK-C16 peptide nanofibers (Cu-GHK NF), the Cu-GHK NF/HA-Ty hydrogel offers remarkable advantages over conventional non-structured Cu-GHK for wound healing. It enhances cell proliferation, migration, and collagen remodeling-critical factors in tissue regeneration. The incorporation of GHK nanofibers complexed with copper ions imparts potent anti-inflammatory effects, promoting cytokine activation and angiogenesis during wound healing. The Cu-GHK NF/hydrogel's unique properties, including in situ photo-crosslinking, ensure high customization and potency in tissue regeneration, providing a cost-effective alternative to growth factors. In vivo experiments further validate its efficacy, demonstrating significant wound closure, collagen remodeling, and increased fibroblast density. Overall, the Cu-GHK NF/HA-Ty hydrogel represents an advanced therapeutic option for wound healing applications.

Liposomes as Carriers of GHK-Cu Tripeptide for Cosmetic Application.

Michał Dymek, Karolina Olechowska, Katarzyna Hąc-Wydro +1 more

Liposomes are self-assembled spherical systems composed of amphiphilic phospholipids. They can be used as carriers of both hydrophobic and hydrophilic substances, such as the anti-aging and wound-healing copper-binding peptide, GHK-Cu (glycyl-L-histidyl-L-lysine). Anionic (AL) and cationic (CL) hydrogenated lecithin-based liposomes were obtained as GHK-Cu skin delivery systems using the thin-film hydration method combined with freeze-thaw cycles and the extrusion process. The influence of total lipid content, lipid composition and GHK-Cu concentration on the physicochemical properties of liposomes was studied. The lipid bilayer fluidity and the peptide encapsulation efficiency (EE) were also determined. Moreover, in vitro assays of tyrosinase and elastase inhibition were performed. Stable GHK-Cu-loaded liposome systems of small sizes (approx. 100 nm) were obtained. The bilayer fluidity was higher in the case of cationic liposomes. As the best carriers, 25 mg/cm3 CL and AL hydrated with 0.5 mg/cm3 GHK-Cu were selected with EE of 31.7 ± 0.9% and 20.0 ± 2.8%, respectively. The obtained results confirmed that the liposomes can be used as carriers for biomimetic peptides such as copper-binding peptide and that the GHK-Cu did not significantly affect the tyrosinase activity but led to 48.90 ± 2.50% elastase inhibition, thus reducing the rate of elastin degeneration and supporting the structural integrity of the skin.

Ultrasensitive and Label-Free Detection of Copper Ions by GHK-Modified Asymmetric Nanochannels.

Pengrong An, Zixin Zhang, Jincan Yang +5 more

Artificial solid-state nanochannels have garnered considerable attention as promising nanofluidic tools for ion/molecular detection, DNA sequencing, and biomimicry. Recently, nanofluidic devices have emerged as cost-effective detection tools for heavy metal ions by modifying stimuli-responsive materials. In this work, high-purity glycyl-l-histidyl-l-lysine (GHK) peptide is synthesized by using 7-diphenylphosphonooxycoumarin-4-methanol (DPCM) as a protecting group and auxiliary carrier by homogeneous synthesis of photocleavable groups. Subsequently, we developed a GHK-modified asymmetric nanochannel nanofluidic diode by covalently attaching the GHK peptide to the inner surface of the nanochannels. This modification facilitated specific recognition and ultra-trace level detection of Cu2+ ions, achieving a detection limit of 10-15 M. Due to the robust complexing ability between Cu2+ and GHK peptide, the GHK-modified asymmetric nanochannels can form GHK-Cu complexes on the inner surface of nanochannels when Cu2+ passes through the nanochannels. This results in changes of current-potential (I-V) properties, which facilitated Cu2+ detection. Theoretical calculations confirmed the high affinity of the GHK peptide for Cu2+, thereby ensuring excellent Cu2+ selectivity. To evaluate the applicability of our system for detecting Cu2+ in real-world scenarios, we analyzed the concentration of Cu2+ in tap water. The GHK-Cu complexes could be dissociated by adding EDTA to the solution, enabling the regeneration and reuse of this ultrasensitive and label-free Cu2+ detection system using GHK-modified asymmetric multi-nanochannels. We anticipate that the GHK-modified asymmetric nanochannels will find future applications in the label-free detection of Cu2+ in domestic water.

Synergy of GHK-Cu and hyaluronic acid on collagen IV upregulation via fibroblast and ex-vivo skin tests.

Fangru Jiang, Yanan Wu, Zhe Liu +2 more

GHK-Cu and HA are two commonly used skin care ingredients, both of which were reported to enhance collagen synthesis. This work aims to investigate their co-effect on collagen regulation.

Relief of ovalbumin-induced airway remodeling by the glycyl-l-histidyl-l-lysine-Cu2+ tripeptide complex via activation of SIRT1 in airway epithelial cells.

Qin Zhang, Jia Liu, Ming-Ming Deng +2 more

Fixed airflow limitation (FAO), prevalent in patients with severe or difficult-to-treat asthma, is mainly caused by airway remodeling. Airway remodeling is initiated by inflammation and involves subsequent pathological changes. Glycyl-l-histidyl-l-lysine (GHK) is a matrikine with anti-inflammatory and antioxidant effects, naturally existing in human tissue. At present, the GHK level in human plasma and whether it is related to airway remodeling of asthma remain unclear. This study was conducted to determine how GHK is involved in airway remodeling in asthma. Our result showed that the plasma GHK levels of patients with asthma were significantly lower than those of age-matched healthy controls. In asthma patients, plasma GHK levels display a moderate correlation with FEF25-75%, and patients with FAO had significantly lower GHK levels. Ovalbumin-induced mice of asthma model treated with PBS or GHK-Cu (a form of GHK with higher bioavailability) were used to evaluate the effect of exogenous GHK supplement on airway remodeling. GHK-Cu administration alleviated airway remodeling, as reflected by decreased peribronchial collagen deposition and airway mucus secretion, and suppressed epithelial-mesenchymal transition. The therapeutical effect related to decreased TGF-β1 level. Successively, network pharmacology and the validation data of experiments in vivo and vitro demonstrated that GHK-Cu decreased TGF-β1 level by increasing SIRT1 expression and activating SIRT1 deacetylation in airway epithelial cells, thereby alleviating airway remodeling. Collectively, decreased plasma GHK levels were related to FAO in asthma patients. Through the direct binding and activation of SIRT1, exogenous GHK-Cu administration alleviated airway remodeling in asthmatic mice.

[Molecular tandem repeat strategy for production ofultrashort peptides].

Chen Zhao, Duanhua Li, Jinjun Li +1 more

Ultrashort peptides have higher stability, tissue penetrability, biocompatibility, and less immunogenicity, and are widely applied in biology and medicine. GHK (glycyl-l-histidyl-l-lysine) and GQPR (glycyl-l-glutamyl-l-prolyl-l-arginine) can stimulate collagen renewal and inhibit collagen degradation. GHK and GQPR have been used in cosmetic anti-wrinkle skincare and make-up products. The most common approach for ultrashort peptide production is the solid-phase synthesis, which is eco-unfriendly due to heavy usage of organic chemical reagents during the manufacturing process. Here we report a new approach to the production of ultrashort peptides. Recombinant expression of ultrashort peptides is usually unfeasible because of the short amino acid sequences. A vector pET28a-Trxm harboring the thioredoxin gene was first constructed for subsequent fusion expression. The tandem repeats of GHK and GQPR genes were used as the templates for rolling circle amplification (RCA). The RCA reaction was tuned to incorporate noncanonical nucleotides 5-methylcytosine to obtain long DNA fragments. Gene sequences with various lengths were generated through double digestion of Acc65 Ⅰ and Apa Ⅰ. The resulting digestion products were gel recovered by size (from 500 bp to 1 500 bp) and cloned into pET28a-Trxm to obtain the recombinant vector pET28a-Trxm-(TRSP)n. The pET28a-Trxm-(TRSP)n was introduced into E. coli BL21(DE3) to generate a library of Trxm-(TRSP)n sequences with a controlled distribution of lengths. Through double digestion and sequencing, positive clones with tandem repeats n=1, 2, 3, 4, 6, 7, 8, 9 were obtained. Protein expression results showed protein bands with corresponding molecular weight, and the protein expression level decreased as the tandem repeats increased. The expression level of Trxm-(TRSP)1 achieved 50% of the total protein, while the expression level of Trxm-(TRSP)2 was 30% of the total protein. The crude extracts from cell pellets were further treated with enterokinase cleavage, and the supernatants containing (TRSP)1 were collected after ultrafiltration and then subjected to trypsin cleavage. HPLC analysis indicated that the ultrashort peptides GHK and GQPR were successfully obtained through two-step cleavage. This study may facilitate the commercial production of ultrashort peptides.

Biomimetic Hydrogel Scaffolds with Copper Peptide-Functionalized RADA16 Nanofiber Improve Wound Healing in Diabetes.

Xinlei Yang, Yu Zhang, Cheng Huang +3 more

Wound healing in diabetes is retarded by the dysfunctional local microenvironment. Although there are many studies using hydrogels as substitutes for natural extracellular matrices (ECMs), hydrogels that can mimic both the structure and functions of natural ECM remain a challenge. Self-assembling peptide RADA16 nanofiber has distinct advantages to provide a biomimetic extracellular matrix nanofiber structure. However, it still lacks biological cues to promote angiogenesis that is of vital significance for diabetic wound healing. With a customized copper peptide glycyl-histidyl-lysine (GHK) functionalized RADA16, an integrated approach using functionalized RADA16 nanofiber to chelate copper ion, is innovatively proposed in this present study. The acquired composite hydrogel holds the biomimetic nanofiber architecture, and exhibits promoting angiogenesis by both enhancing adhesion and proliferation of endothelial cells (EC) in vitro and neovascularization in vivo. It shows that the functionalized nanofiber scaffolds significantly accelerated wound closure, collagen deposition, and tissue remodeling both in healthy and diabetic mice. Furthermore, immunohistochemical analysis give evidence that an upregulated expression of eNOS and CD31 in the copper peptide-functionalized RADA16 treated group. It can be envisioned that this scaffold can serve as a promising dressing for diabetic wound healing.

Polyaspartic acid, 2-acrylamido-2-Methyl propane sulfonic acid and sodium alginate based biocompatible stimuli responsive polymer gel for controlled release of GHK-Cu peptide for wound healing.

Shilpa Sharma, Mohammad Faiyaz Anwar, Amit Kumar Dinda +3 more

Stimuli responsive polymer based on Polyaspartic acid, 2-Acrylamido-2-methylpropane sulfonic acid and sodium alginate (NaAlg) were synthesized using two cross-linkers Ethylene glycol dimethacrylate (EGDMA) and TMPTA (Trimethylolpropane triacrylate). The polymers were standardized and optimized to obtain a polymer with maximum swelling in distilled water, saline, glucose and solutions of varying pH. The synthesized polymer swelled well in distilled water, glucose solution and acidic- alkaline medium. The biocompatibility of the polymer was evaluated for blood compatibility and protein adsorption. The polymer with maximum swelling property was used for peptide release studies. The polymer was further used to study the peptide encapsulation and release efficiency of the polymeric material which was confirmed by FTIR, Scanning Emission Microscope and EDX. The encapsulation efficiency of the polymer for encapsulating (glycyl-l-histidyl-l-lysine-copper) GHK-Cu was observed to be 55.26% and peptide release of 51.84% was observed for Ethylene glycol dimethacrylate based polymer after 24 h whereas for Trimethylolpropane triacrylate based polymer the encapsulation efficiency was observed to be 49.6% and release was 39.01%. The EGDMA based polymer was further examined under in vivo studies in order to evaluate the efficiency of the synthesized polymer. The in vivo studies include wound closure, histopathological analysis, biochemical and toxicity assay. The material has shown promising results for both in vivo and in vitro studies.

Expression and Purification of Recombinant GHK Tripeptides Are Able to Protect against Acute Cardiotoxicity from Exposure to Waterborne-Copper in Zebrafish.

Chung-Der Hsiao, Hsin-Hui Wu, Nemi Malhotra +6 more

In this study, an alternative method is developed to replace chemical synthesis to produce glycyl-histidyl-lysine (GHK) tripeptides with a bacterial fermentation system. The target GHK tripeptides are cloned into expression plasmids carrying histidine-glutathione-S-transferase (GST) double tags and TEV (tobacco etch virus) cleavage sites at the N-terminus. After overexpression in Escherichia coli (E. coli) BL21 cells, the recombinant proteins are purified and recovered by high-pressure liquid chromatography (HPLC). UV-vis absorption spectroscopy was used to investigate the chemical and biological properties of the recombinant GHK tripeptides. The results demonstrated that one recombinant GHK tripeptide can bind one copper ion to form a GHK-Cu complex with high affinity, and the recombinant GHK peptide to copper ion ratio is 1:1. X-ray absorption near-edge spectroscopy (XANES) of the copper ions indicated that the oxidation state of copper in the recombinant GHK-Cu complexes here was Cu(II). All of the optical spectrum evidence suggests that the recombinant GHK tripeptide appears to possess the same biophysical and biochemical features as the GHK tripeptide isolated from human plasma. Due to the high binding affinity of GHK tripeptides to copper ions, we used zebrafish as an in vivo model to elucidate whether recombinant GHK tripeptides possess detoxification potential against the cardiotoxicity raised by waterborne Cu(II) exposure. Here, exposure to Cu(II) induced bradycardia and heartbeat irregularity in zebrafish larvae; however, the administration of GHK tripeptides could rescue those experiencing cardiotoxicity, even at the lowest concentration of 1 nM, where the GHK-Cu complex minimized CuSO4-induced cardiotoxicity effects at a GHK:Cu ratio of 1:10. On the other hand, copper and the combination with the GHK tripeptide did not significantly alter other cardiovascular parameters, including stroke volume, ejection fraction, and fractional shortening. Meanwhile, the heart rate and cardiac output were boosted after exposure with 1 nM of GHK peptides. In this study, recombinant GHK tripeptide expression was performed, along with purification and chemical property characterization, which revealed a potent cardiotoxicity protection function in vivo with zebrafish for the first time.

Enhanced angiogenic effects of RGD, GHK peptides and copper (II) compositions in synthetic cryogel ECM model.

Mohamed Zoughaib, Duong Luong, Ruslan Garifullin +3 more

Synthetic oligopeptides are a promising alternative to natural full-length growth factors and extracellular matrix (ECM) proteins in tissue regeneration and therapeutic angiogenesis applications. In this work, angiogenic properties of dual and triple compositions containing RGD, GHK peptides and copper (II) ions (Cu2+) were for the first time studied. To reveal specific in vitro effects of these compositions in three-dimensional scaffold, adamantyl group bearing peptides, namely Ada-Ahx-GGRGD (1) and Ada-Ahx-GGGHK (2), were effectively immobilized in bioinert pHEMA macroporous cryogel via host-guest β-cyclodextrin-adamantane interaction. The cryogels were additionally functionalized with Cu2+ via the formation of GHK-Cu complex. Angiogenic responses of HUVECs grown within the cryogel ECM model were analyzed. The results demonstrate that the combination of RGD with GHK and further with Cu2+ dramatically increases cell proliferation, differentiation, and production of a series of angiogenesis related cytokines and growth factors. Furthermore, the level of glutathione, a key cellular antioxidant and redox regulator, was altered in relation to the angiogenic effects. These results are of particular interest for establishing the role of multiple peptide signals on regeneration related processes and for developing improved tissue engineering materials.

Hydrogels based on low-methoxyl amidated citrus pectin and flaxseed gum formulated with tripeptide glycyl-l-histidyl-l-lysine improve the healing of experimental cutting wounds in rats.

Alla Synytsya, Pavla Poučková, Marie Zadinová +5 more

Hydrogels based on natural and modified polysaccharides represent growing group of suitable matrices for the construction of effective wound healing materials. Bioactive tripeptide glycyl-l-histidyl-l-lysine and amino acid α-l-arginine are known to accelerate wound healing and skin repair. In this study, hydrogels based on low-methoxyl amidated citrus pectin or flaxseed gum were prepared and used for the transport of these healing agents to the experimental cutting wounds affected by extensive skin damage. Fourier-transform infrared spectroscopy, rheology, differential scanning calorimetry, scanning electron microscopy, swelling and release tests confirmed that these hydrogels differed in structure and physical properties. The cationic tripeptide was found to bind to carboxylic groups in LMA pectin, and the C3OH hydroxyl and ring oxygen O5 are involved in this interaction. The pectin hydrogel showed high viscosity and strong elastic properties, while the flaxseed gum hydrogel was characterised as a viscoelastic system of much lower viscosity. The former hydrogel released the drugs very slowly, while the latter hydrogel demonstrated zero order releasing kinetics optimal for drug delivery. In the in vivo wound healing testing on rats, both polysaccharide hydrogels improved the healing process mediated by the mentioned biomolecules. The tripeptide applied in the hydrogels showed significantly higher healing degree and lower healing time than in the control animals without treatment and when it was applied in an aqueous solution. Despite the absence of a synergistic effect, the mixture of the tripeptide and α-l-arginine in the hydrogels was also quite effective in wound healing. According to histological analysis, complete healing was achieved only when using the tripeptide in the flaxseed gum hydrogel. These observations might have an important prospect in clinical application of polysaccharide hydrogels.

Ternary Cu(II) Complex with GHK Peptide and Cis-Urocanic Acid as a Potential Physiologically Functional Copper Chelate.

Karolina Bossak-Ahmad, Marta D Wiśniewska, Wojciech Bal +2 more

The tripeptide NH2-Gly-His-Lys-COOH (GHK), cis-urocanic acid (cis-UCA) and Cu(II) ions are physiological constituents of the human body and they co-occur (e.g., in the skin and the plasma). While GHK is known as Cu(II)-binding molecule, we found that urocanic acid also coordinates Cu(II) ions. Furthermore, both ligands create ternary Cu(II) complex being probably physiologically functional species. Regarding the natural concentrations of the studied molecules in some human tissues, together with the affinities reported here, we conclude that the ternary complex [GHK][Cu(II)][cis-urocanic acid] may be partly responsible for biological effects of GHK and urocanic acid described in the literature.

Theoretical study of copper binding to GHK peptide.

Nadiyah Alshammari, James A Platts

We report ligand field molecular mechanics, density functional theory and semi-empirical studies on the binding of Cu(II) to GlyHisLys (GHK) peptide. Following exhaustive conformational searching using molecular mechanics, we show that relative energy and geometry of conformations are in good agreement between GFN2-xTB semi-empirical and B3LYP-D DFT levels. Conventional molecular dynamics simulation of Cu-GHK shows the stability of the copper-peptide binding over 100 ps trajectory. Four equatorial bonds in 3N1O coordination remain stable throughout simulation, while a fifth in apical position from C-terminal carboxylate is more fluxional. We also show that the automated conformer and rotamer search algorithm CREST is able to correctly predict the metal binding position from a starting point consisting of separated peptide, copper and water.

Protective effects of GHK-Cu in bleomycin-induced pulmonary fibrosis via anti-oxidative stress and anti-inflammation pathways.

Wen-Hui Ma, Meng Li, Hai-Feng Ma +5 more

Idiopathic pulmonary fibrosis (IPF) is a serious lung problem with advancing and diffusive pulmonary fibrosis as the pathologic basis, and with oxidative stress and inflammation as the key pathogenesis. Glycyl-L-histidyl-l-lysine (GHK) is a tripeptide participating into wound healing and regeneration. GHK-Cu complexes improve GHK bioavailability. Thus, the current study aimed to explore the therapeutic role of GHK-Cu on bleomycin (BLM)-induced pulmonary fibrosis in a mouse model.