Hollow polydopamine nanoparticles loading with peptide RL-QN15: a new pro-regenerative therapeutic agent for skin wounds

Simultaneous regulation of AGE/RAGE signaling and MMP-9 expression by an immunomodulating hydrogel accelerates healing in diabetic wounds

PURPOSE

In chronic hyperglycemia, the advanced glycation end product (AGE) interacts with its receptor (RAGE) and contributes to impaired wound healing by inducing oxidative stress, generating dysfunctional macrophages, and prolonging the inflammatory response. Additionally, uncontrolled levels of proteases, including metallomatrix protease-9 (MMP-9), in the diabetic wound bed degrade the extracellular matrix (ECM) and biological cues that augment healing. A multifunctional antimicrobial hydrogel (Immuno-gel) containing RAGE and MMP-9 inhibitors can regulate the wound microenvironment and promote scar-free healing.

RESULTS

Immuno-gel was characterized and the wound healing efficacy was determined in vitro cell culture and in vivo diabetic Wistar rat wound model using ELISA, Western blot, and Immunofluorescence staining. The Immuno-gel exhibited a highly porous morphology with excellent in vitro cytocompatibility. AGE-stimulated macrophages treated with the Immuno-gel released higher levels of pro-healing cytokines in vitro. In the hydrogel-wound interface of diabetic Wistar rats, Immuno-gel treatment significantly reduced MMP-9 and NF-κB expression and enhanced pro-healing (M2) macrophage population and pro-healing cytokines.

CONCLUSION

Altogether, this study suggests that Immuno-gel simultaneously attenuates macrophage dysfunction through the inhibition of AGE/RAGE signaling and reduces MMP-9 overexpression, both of which favor scar-free healing. The combinatorial treatment with RAGE and MMP-9 inhibitors via Immuno-gel simultaneously modulates the diabetic wound microenvironment, making it a promising novel treatment to accelerate diabetic wound healing.

Therapeutic Potential of Nanocarrier Mediated Delivery of Peptides for Wound Healing: Current Status, Challenges and Future Prospective

Wound healing presents a complex physiological process that involves a sequence of events orchestrated by various cellular and molecular mechanisms. In recent years, there has been growing interest in leveraging nanomaterials and peptides to enhance wound healing outcomes. Nanocarriers offer unique properties such as high surface area-to-volume ratio, tunable physicochemical characteristics, and the ability to deliver therapeutic agents in a controlled manner. Similarly, peptides, with their diverse biological activities and low immunogenicity, hold great promise as therapeutics in wound healing applications. In this review, authors explore the potential of peptides as bioactive components in wound healing formulations, focusing on their antimicrobial, anti-inflammatory, and pro-regenerative properties. Despite the significant progress made in this field, several challenges remain, including the need for standardized characterization methods, optimization of biocompatibility and safety profiles, and translation from bench to bedside. Furthermore, developing multifunctional nanomaterial-peptide hybrid systems represents promising avenues for future research. Overall, the integration of nanomaterials made up of natural or synthetic polymers with peptide-based formulations holds tremendous therapeutic potential in advancing the field of wound healing and improving clinical outcomes for patients with acute and chronic wounds.

Wet adhesive hydrogels based on niobium carbide for experimental research of oral mucosal impairment

Oral mucosal impairment is a prevalent oral disease that frequently causes pain for patients. Conventional treatments have limited effectiveness and can cause adverse reactions. Furthermore, the moist and dynamic nature of the oral mucosal environment makes persistent adherence of conventional materials challenging, which can affect treatment efficacy. In this study, we investigated the potential of a NbC/TA-GelMA hydrogel system, where niobium carbide (NbC) and tannic acid (TA) were added to gelatin methacryloyl (GelMA), for repairing oral mucosal impairment. The wet adhesion properties of NbC/TA-GelMA hydrogels were confirmed by the inclusion of TA with a catechol-rich group. In addition, the photothermal effect of NbC/TA-GelMA hydrogel under near-infrared light, synergizing with TA, provided sustained antibacterial action. Furthermore, the NbC/TA-GelMA hydrogel effectively healed damaged oral mucosa of rats.

Hydrogel Loaded with Peptide-Containing Nanocomplexes: Symphonic Cooperation of Photothermal Antimicrobial Nanoparticles and Prohealing Peptides for the Treatment of Infected Wounds

Current treatment for chronic infectious wounds is limited due to severe drug resistance in certain bacteria. Therefore, the development of new composite hydrogels with nonantibiotic antibacterial and pro-wound repair is important. Here, we present a photothermal antibacterial composite hydrogel fabricated with a coating of Fe2+ cross-linked carboxymethyl chitosan (FeCMCS) following the incorporation of melanin nanoparticles (MNPs) and the CyRL-QN15 peptide. Various physical and photothermal properties of the hydrogel were characterized. Cell proliferation, migration, cycle, and free-radical scavenging activity were assessed, and the antimicrobial properties of the hydrogel were probed by photothermal therapy. The effects of the hydrogel were validated in a model of methicillin-resistant Staphylococcus aureus (MRSA) infection with full-thickness injury. This effect was further confirmed by changes in cytokines associated with inflammation, re-epithelialization, and angiogenesis on the seventh day after wound formation. The MNPs demonstrated robust photothermal conversion capabilities. The composite hydrogel (MNPs/CyRL-QN15/FeCMCS) promoted keratinocyte and fibroblast proliferation and migration while exhibiting high antibacterial efficacy, effectively killing more than 95% of Gram-positive and Gram-negative bacteria. In vivo study using an MRSA-infected full-thickness injury model demonstrated good therapeutic efficacy of the hydrogel in promoting regeneration and remodeling of chronically infected wounds by alleviating inflammatory response and accelerating re-epithelialization and collagen deposition. The MNPs/CyRL-QN15/FeCMCS hydrogel showed excellent antibacterial and prohealing effects on infected wounds, indicating potential as a promising candidate for wound healing promotion.

3D bioprinting of Salvianolic acid B-sodium alginate-gelatin skin scaffolds promotes diabetic wound repair via antioxidant, anti-inflammatory, and proangiogenic effects

In patients with diabetic wounds, wound healing is impaired due to the presence of persistent oxidative stress, an altered inflammatory response, and impaired angiogenesis and epithelization. Salvianolic acid B (SAB), which is derived from the Chinese medicinal plant Salvia miltiorrhiza, has been found to exhibit antioxidant, anti-inflammatory, and proangiogenic effects. Previous studies have used 3D bioprinting technology incorporating sodium alginate (SA) and gelatin (Gel) as basic biomaterials to successfully produce artificial skin. In the current study, 3D bioprinting technology was used to incorporate SAB into SA-Gel to form a novel SAB-SA-Gel composite porous scaffold. The morphological characteristics, physicochemical characteristics, biocompatibility, and SAB release profile of the SAB-SA-Gel scaffolds were evaluated in vitro. In addition, the antioxidant, anti-inflammatory, and proangiogenic abilities of the SAB-SA-Gel scaffolds were evaluated in cells and in a rat model. Analysis demonstrated that 1.0 wt% (the percentage of SAB in the total weight of the solution containing SA and Gel) SAB-SA-Gel scaffolds had strong antioxidant, anti-inflammatory, and proangiogenic properties both in cells and in the rat model. The 1.0% SAB-SA-Gel scaffold reduced the expression of tumor necrosis factor-α, interleukin-6, and interluekin-1β and increased the expression of transforming growth factor-β. In addition, this scaffold removed excessive reactive oxygen species by increasing the expression of superoxide dismutase, thereby protecting fibroblasts from injury. The scaffold increased the expression of vascular endothelial growth factor and platelet/endothelial cell adhesion molecule-1, accelerated granulation tissue regeneration and collagen deposition, and promoted wound healing. These findings suggest that this innovative scaffold may have promise as a simple and efficient approach to managing diabetic wound repair.

Amphibian-derived peptide RL-RF10 ameliorates paraquat-induced pulmonary fibrosis injury

Pulmonary fibrosis is the result of dysfunctional repair after lung tissue injury, characterized by fibroblast proliferation and massive extracellular matrix aggregation. Once fibrotic lesions develop, effective treatment is difficult, with few drugs currently available. Here, we identified a short cyclic decapeptide RL-RF10 derived from frog skin secretions as a potential novel lead molecule for the amelioration of pulmonary fibrosis. In vivo experiments indicated that RL-RF10 treatment ameliorated lung histopathological damage and fibrogenesis after paraquat (PQ) induction in a concentration-dependent manner. On day 7, bronchoalveolar lavage fluid assays performed on mice showed that RL-RF10 exerted anti-inflammatory effects by decreasing the expression of inflammation-related factors, including transforming growth factor-β1 (TGF-β1) and tumor necrosis factor-α, in lung tissue. In addition, RL-RF10 down-regulated the levels of collagen I, collagen III, and vimentin, while increasing the expression of E-cadherin to inhibit epithelial-mesenchymal transition. Further research demonstrated that the SMAD2/3 signaling pathway, which is strongly linked to TGF-β1, played a critical function in enhancing the pulmonary fibrosis relief achieved by RL-RF10. Both in vivo and in vitro assays showed that RL-RF10 treatment led to a significant reduction in the phosphorylation levels of SMAD2 and SMAD3 following PQ induction. Overall, we investigated the protective effects and underlying mechanisms of the RL-RF10 peptide against pulmonary fibrosis and demonstrated its potential as a novel therapeutic drug candidate for the treatment of pulmonary fibrotic diseases.

miR-186-5p targets TGFβR2 to inhibit RAW264.7 cell migration and proliferation during mouse skin wound healing

BACKGROUND

Active peptides play a vital role in the development of new drugs and the identification and discovery of drug targets. As the first reported native peptide homodimer with pro-regenerative potency, OA-GP11d could potentially be used as a novel molecular probe to help elucidate the molecular mechanism of skin wound repair and provide new drug targets.

METHODS

Bioinformatics analysis and luciferase assay were adopted to determine microRNAs (miRNAs) and its target. The prohealing potency of the miRNA was determined by MTS and a Transwell experiment against mouse macrophages. Enzyme-linked immunosorbent assay, realtime polymerase chain reaction, and western blotting were performed to explore the molecular mechanisms.

RESULTS

In this study, OA-GP11d was shown to induce Mus musculus microRNA-186-5p (mmu-miR-186-5p) down-regulation. Results showed that miR-186-5p had a negative effect on macrophage migration and proliferation as well as a targeted and negative effect on TGF-β type II receptor (TGFβR2) expression and an inhibitory effect on activation of the downstream SMAD family member 2 (Smad2) and protein-p38 kinase signaling pathways. Importantly, delivery of a miR-186-5p mimic delayed skin wound healing in mice.

CONCLUSION

miR-186-5p regulated macrophage migration and proliferation to delay wound healing through the TGFβR2/Smad2/p38 molecular axes, thus providing a promising new pro-repair drug target.

Peptide RL-QN15 promotes wound healing of diabetic foot ulcers through p38 mitogen-activated protein kinase and smad3/miR-4482-3p/vascular endothelial growth factor B axis

Background

Wound management of diabetic foot ulcers (DFUs) is a complex and challenging task, and existing strategies fail to meet clinical needs. Therefore, it is important to develop novel drug candidates and discover new therapeutic targets. However, reports on peptides as molecular probes for resolving issues related to DFUs remain rare. This study utilized peptide RL-QN15 as an exogenous molecular probe to investigate the underlying mechanism of endogenous non-coding RNA in DFU wound healing. The aim was to generate novel insights for the clinical management of DFUs and identify potential drug targets.

Methods

We investigated the wound-healing efficiency of peptide RL-QN15 under diabetic conditions using in vitro and in vivo experimental models. RNA sequencing, in vitro transfection, quantitative real-time polymerase chain reaction, western blotting, dual luciferase reporter gene detection, in vitro cell scratches, and cell proliferation and migration assays were performed to explore the potential mechanism underlying the promoting effects of RL-QN15 on DFU repair.

Results

Peptide RL-QN15 enhanced the migration and proliferation of human immortalized keratinocytes (HaCaT cells) in a high-glucose environment and accelerated wound healing in a DFU rat model. Based on results from RNA sequencing, we defined a new microRNA (miR-4482-3p) related to the promotion of wound healing. The bioactivity of miR-4482-3p was verified by inhibiting and overexpressing miR-4482-3p. Inhibition of miR-4482-3p enhanced the migration and proliferation ability of HaCaT cells as well as the expression of vascular endothelial growth factor B (VEGFB). RL-QN15 also promoted the migration and proliferation ability of HaCaT cells, and VEGFB expression was mediated via inhibition of miR-4482-3p expression by the p38 mitogen-activated protein kinase (p38MAPK) and smad3 signaling pathways.

Conclusions

RL-QN15 is an effective molecule for the treatment of DFUs, with the underlying mechanism related to the inhibition of miR-4482-3p expression via the p38MAPK and smad3 signaling pathways, ultimately promoting re-epithelialization, angiogenesis and wound healing. This study provides a theoretical basis for the clinical application of RL-QN15 as a molecular probe in promoting DFU wound healing.

Peptide OA-VI12 restrains melanogenesis in B16 cells and C57B/6 mouse ear skin via the miR-122-5p/Mitf/Tyr axis

Excessive melanogenesis leads to hyperpigmentation, which is one of the common skin conditions in humans. Existing whitening cosmetics cannot meet market needs due to their inherent limitations. Thus, the development of novel skin-whitening agents continues to be a challenge. The peptide OA-VI12 from the skin of amphibians at high altitude has attracted attention due to its remarkable anti light damage activity. However, whether OA-VI12 has the skin-whitening effect of inhibiting melanogenesis is still. Mouse melanoma cells (B16) were used to study the effect of OA-VI12 on cell viability and melanin content. The pigmentation model of C57B/6 mouse ear skin was induced by UVB and treated with OA-VI12. Melanin staining was used to observe the degree of pigmentation. MicroRNA sequencing, quantitative real-time PCR (qRT-PCR), immunofluorescence analysis and Western blot were used to detect the change of factor expression. Double luciferase gene report experiment was used to prove the regulatory relationship between miRNA and target genes. OA-VI12 has no effect on the viability of B16 cells in the concentration range of 1-100 μM and significantly inhibits the melanin content of B16 cells. Topical application of OA-VI12, which exerted transdermal potency, prevented UVB-induced pigmentation of ear skin. MicroRNA sequencing and double luciferase reporter analysis results showed that miR-122-5p, which directly regulated microphthalmia-associated transcription factor (Mitf), had significantly different expression before and after treatment with OA-VI12. Mitf is a simple helix loop and leucine zipper transcription factor that regulates tyrosinase (Tyr) expression by binding to the M-box promoter element of Tyr. qRT-PCR, immunofluorescence analysis and Western blot showed that OA-VI12 up-regulated the expression of miR-122-5p and inhibited the expression of Mitf and Tyr. The effects of OA-VI12 on melanogenesis inhibition in vitro and in vivo may involve the miR-122-5p/Mitf/tyr axis. OA-VI12 represents the first report on a natural amphibian-derived peptide with skin-whitening capacity and the first report of miR-122-5p as a target for regulating melanogenesis, thereby demonstrating its potential as a novel skin-whitening agent and highlighting amphibian-derived peptides as an underdeveloped resource.

Growth factors in the treatment of Achilles tendon injury

Achilles tendon (AT) injury is one of the most common tendon injuries, especially in athletes, the elderly, and working-age people. In AT injury, the biomechanical properties of the tendon are severely affected, leading to abnormal function. In recent years, many efforts have been underway to develop effective treatments for AT injuries to enable patients to return to sports faster. For instance, several new techniques for tissue-engineered biological augmentation for tendon healing, growth factors (GFs), gene therapy, and mesenchymal stem cells were introduced. Increasing evidence has suggested that GFs can reduce inflammation, promote extracellular matrix production, and accelerate AT repair. In this review, we highlighted some recent investigations regarding the role of GFs, such as transforming GF-β(TGF-β), bone morphogenetic proteins (BMP), fibroblast GF (FGF), vascular endothelial GF (VEGF), platelet-derived GF (PDGF), and insulin-like GF (IGF), in tendon healing. In addition, we summarized the clinical trials and animal experiments on the efficacy of GFs in AT repair. We also highlighted the advantages and disadvantages of the different isoforms of TGF-β and BMPs, including GFs combined with stem cells, scaffolds, or other GFs. The strategies discussed in this review are currently in the early stages of development. It is noteworthy that although these emerging technologies may potentially develop into substantial clinical treatment options for AT injury, definitive conclusions on the use of these techniques for routine management of tendon ailments could not be drawn due to the lack of data.

Amphibian-derived wound healing peptides: chemical molecular treasure trove for skin wound treatment

Amphibian-derived wound healing peptides thus offer new intervention measures and strategies for skin wound tissue regeneration. As novel drug lead molecules, wound healing peptides can help analyze new mechanisms and discover new drug targets. Previous studies have identified various novel wound healing peptides and analyzed novel mechanisms in wound healing, especially competing endogenous RNAs (ceRNAs) (e.g., inhibition of miR-663a promotes skin repair). In this paper, we review amphibian-derived wound healing peptides, including the acquisition, identification, and activity of peptides, a combination of peptides with other materials, and the analysis of underlying mechanisms, to better understand the characteristics of wound healing peptides and to provide a molecular template for the development of new wound repair drugs.

Functionalization of and through Melanin: Strategies and Bio-Applications

A unique feature of nanoparticles for bio-application is the ease of achieving multi-functionality through covalent and non-covalent functionalization. In this way, multiple therapeutic actions, including chemical, photothermal and photodynamic activity, can be combined with different bio-imaging modalities, such as magnetic resonance, photoacoustic, and fluorescence imaging, in a theragnostic approach. In this context, melanin-related nanomaterials possess unique features since they are intrinsically biocompatible and, due to their optical and electronic properties, are themselves very efficient photothermal agents, efficient antioxidants, and photoacoustic contrast agents. Moreover, these materials present a unique versatility of functionalization, which makes them ideal for the design of multifunctional platforms for nanomedicine integrating new functions such as drug delivery and controlled release, gene therapy, or contrast ability in magnetic resonance and fluorescence imaging. In this review, the most relevant and recent examples of melanin-based multi-functionalized nanosystems are discussed, highlighting the different methods of functionalization and, in particular, distinguishing pre-functionalization and post-functionalization. In the meantime, the properties of melanin coatings employable for the functionalization of a variety of material substrates are also briefly introduced, especially in order to explain the origin of the versatility of melanin functionalization. In the final part, the most relevant critical issues related to melanin functionalization that may arise during the design of multifunctional melanin-like nanoplatforms for nanomedicine and bio-application are listed and discussed.

Reversing Immune Suppression and Potentiating Photothermal Immunotherapy via Bispecific Immune Checkpoint Inhibitor Loaded Hollow Polydopamine Nanospheres

Despite the great achievements of immune checkpoint blockade (ICB) therapy on programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) axis, ICB monotherapy still faces obstacles in eradicating solid tumors due to the lack of tumor-associated antigens or tumor-specific cytotoxicity. Photothermal therapy (PTT) is a potential therapeutic modality because it can noninvasively kill tumor cells by thermal ablation and generate both tumor-specific cytotoxicity and immunogenicity, which holds great feasibility to improve the efficiency of ICB by providing complementary immunomodulation. Except for the PD-1/PD-L1 axis, the cluster of differentiation 47 (CD47)/signal regulatory protein alpha (SIRPα) pathway has been considered as a novel strategy of tumor cells to evade the surveillance of macrophages and inactivate the immune response of PD-L1 blockade therapy. Therefore, it is necessary to synergize the antitumor effect of dual-targeting PD-L1 and CD47. Although promising, the application of PD-L1/CD47 bispecific antibodies, especially in combination with PTT, remains a formidable problem, due to the low objective response, activity loss at relatively high temperature, or nonvisualization. Herein, instead of using antibodies, we use MK-8628 (MK) to down-regulate both PD-L1 and CD47 simultaneously through halting the active transcription of oncogene c-MYC, leading to elicitation of the immune response. The hollow polydopamine (HPDA) nanospheres are introduced as a biocompatible nanoplatform with high loading capacity and magnetic resonance imaging (MRI) ability to deliver MK and induce PTT (HPDA@MK). Compared to preinjection, HPDA@MK exhibits the strongest MRI signal at 6 h postintravenous injection to guide the precise combined treatment time. However, due to the local delivery and controlled release of inhibitors, HPDA@MK down-regulates c-MYC/PD-L1/CD47, promotes the activation and recruitment of cytotoxic T cells, regulates the M2 macrophages polarization in tumor sites, and especially boosts the combined therapeutic efficacy. Collectively, our work presents a simple but distinctive approach for c-MYC/PD-L1/CD47-targeted immunotherapy combined with PTT that may provide a desirable and feasible strategy for the treatment of other clinical solid tumors.

OL-FS13 Alleviates Cerebral Ischemia-reperfusion Injury by Inhibiting miR-21-3p Expression

BACKGROUND

OL-FS13, a neuroprotective peptide derived from Odorrana livida, can alleviate cerebral ischemia-reperfusion (CI/R) injury, although the specific underlying mechanism remains to be further explored.

OBJECTIVE

The effect of miR-21-3p on the neural-protective effects of OL-FS13 was examined.

METHODS

In this study, the multiple genome sequencing analysis, double luciferase experiment, RT-qPCR, and Western blotting were used to explore the mechanism of OL-FS13.

RESULTS

Showed that over-expression of miR-21-3p against the protective effects of OL-FS13 on oxygen- glucose deprivation/re-oxygenation (OGD/R)-damaged pheochromocytoma (PC12) cells and in CI/R-injured rats. miR-21-3p was then found to target calcium/calmodulin-dependent protein kinase 2 (CAMKK2), and its overexpression inhibited the expression of CAMKK2 and phosphorylation of its downstream adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), thereby inhibiting the therapeutic effects of OL-FS13 on OGD/R and CI/R. Inhibition of CAMKK2 also antagonized up-regulated of nuclear factor erythroid 2-related factor 2 (Nrf-2) by OL-FS13, thereby abolishing the antioxidant activity of the peptide.

CONCLUSION

Our results showed that OL-FS13 alleviated OGD/R and CI/R by inhibiting miR-21-3p to activate the CAMKK2/AMPK/Nrf-2 axis.

Scorpion venom peptide HsTx2 suppressed PTZ-induced seizures in mice via the circ_0001293/miR-8114/TGF-β2 axis

BACKGROUND

Due to the complexity of the mechanisms involved in epileptogenesis, the available antiseizure drugs (ASDs) do not meet clinical needs; hence, both the discovery of new ASDs and the elucidation of novel molecular mechanisms are very important.

METHODS

BALB/c mice were utilized to establish an epilepsy model induced by pentylenetetrazol (PTZ) administration. The peptide HsTx2 was administered for treatment. Primary astrocyte culture, immunofluorescence staining, RNA sequencing, identification and quantification of mouse circRNAs, cell transfection, bioinformatics and luciferase reporter analyses, enzyme-linked immunosorbent assay, RNA extraction and reverse transcription-quantitative PCR, Western blot and cell viability assays were used to explore the potential mechanism of HsTx2 via the circ_0001293/miR-8114/TGF-β2 axis.

RESULTS

The scorpion venom peptide HsTx2 showed an anti-epilepsy effect, reduced the inflammatory response, and improved the circular RNA circ_0001293 expression decrease caused by PTZ in the mouse brain. Mechanistically, in astrocytes, circ_0001293 acted as a sponge of endogenous microRNA-8114 (miR-8114), which targets transforming growth factor-beta 2 (TGF-β2). The knockdown of circ_0001293, overexpression of miR-8114, and downregulation of TGF-β2 all reversed the anti-inflammatory effects and the influence of HsTx2 on the MAPK and NF-κB signaling pathways in astrocytes. Moreover, both circ_0001293 knockdown and miR-8114 overexpression reversed the beneficial effects of HsTx2 on inflammation, epilepsy progression, and the MAPK and NF-κB signaling pathways in vivo.

CONCLUSIONS

HsTx2 suppressed PTZ-induced epilepsy by ameliorating inflammation in astrocytes via the circ_0001293/miR-8114/TGF-β2 axis. Our results emphasized that the use of exogenous peptide molecular probes as a novel type of ASD, as well as to explore the novel endogenous noncoding RNA-mediated mechanisms of epilepsy, might be a promising research area.

OL-FS13 alleviates experimental cerebral ischemia-reperfusion injury

Cerebral ischemia-reperfusion (I/R) is the main cause of neurological injury after stroke. However, existing treatments for I/R injury are relatively poor, and relevant drugs need to be further explored. Amphibians have received increasing attention as a resource bank of bioactive peptides. However, reports on neuroprotective peptides from amphibians remain extremely rare. Here, we identified a new neuroprotective peptide (OL-FS13, amino acid sequence: FSLLLTWWRRRVC) from the odorous frog species Odorrana livida using a constructed cDNA library. OL-FS13 significantly improving infarct volume, behavioral and histological abnormalities in rats, and also showed neuroprotective activities in PC12 cell (by oxygen glucose deprivation/reoxygenation, OGD/R). Mechanistically, OL-FS13 increased the level of antioxidative enzymes to resist oxidative stress and alleviated endoplasmic reticulum (ER) stress induced by I/R and OGD/R. The use of ML385 (Nrf2 inhibitor) indicated that OL-FS13 relieved nerve damage caused by oxidative and ER stress by increasing the nuclear displacement of Nrf2. Collectively, this research provides a novel drug candidate for the clinical cerebral I/R curation.

Zn2+ Cross-Linked Alginate Carrying Hollow Silica Nanoparticles Loaded with RL-QN15 Peptides Provides Promising Treatment for Chronic Skin Wounds

Chronic and non-healing wounds pose a great challenge to clinical management and patients. Many studies have explored novel interventions against skin wounds, with bioactive peptides, nanoparticles, and hydrogels arousing considerable attention regarding their therapeutic potential. In this study, the prohealing peptide RL-QN15 was loaded into hollow silica nanoparticles (HSNs), with these HSN@RL-QN15 nanocomposites then combined with zinc alginate (ZA) gels to obtain HSN@RL-QN15/ZA hydrogel. The characteristics, biological properties, and safety profiles of the hydrogel composites were then evaluated. Results showed that the hydrogel had good porosity, hemocompatibility, biocompatibility, and broad-spectrum antimicrobial activity, with the slow release of loaded RL-QN15. Further analysis indicated that the hydrogel promoted skin cell proliferation and keratinocyte scratch repair, regulated angiogenesis, reduced inflammation, and accelerated re-epithelialization and granulation tissue formation, resulting in the rapid healing of both full-thickness skin wounds and methicillin-resistant Staphylococcus aureus biofilm-infected chronic wounds in mice. This peptide-based hydrogel provides a novel intervention for the treatment of chronic skin wounds and shows promise as a wound dressing in the field of tissue regeneration.

Short Hexapeptide Optimized from Rice-Derived Peptide 1 Shows Promising Anti-hyperuricemia Activities

Plant-derived peptides are a treasure trove for new-generation anti-hyperuricemia drugs. In the current study, we optimized a short hexapeptide rice-derived peptide 1 (RDP1)-M3 (AAAAGA) according to the anti-hyperuricemia RDP1 peptide identified from rice in our previous research. Results showed that RDP1-M3 exerted better hyperuricemia-alleviating and xanthine oxidase (XOD)-inhibiting potency in mice than RDP1. The biodistribution of RDP1-M3 was also analyzed. RDP1-M3 directly decreased XOD and uric acid levels in vivo and in vitro. In addition, RDP1-M3 reduced the expression of urate transporter 1 and glucose transporter 9, increased the level of organic anion transporter 1, reduced the expression of NOD-like receptor superfamily pyrin 3 inflammasomes, and reduced the levels of interleukin-1β and tumor necrosis factor-α of hyperuricemic mice. Thus, our results indicated that the optimized short hexapeptide RDP1-M3 may be a candidate drug for anti-hyperuricemia.

A new peptide originated from amphibian skin alleviates the ultraviolet B-induced skin photodamage

Although amphibian-derived bioactive peptides have attracted increasing attention for their potential use in the treatment of photodamage, research is still in its infancy. In this study, we obtained a new antioxidant peptide, named OA-GI13 (GIWAPWPPRAGLC), from the skin of the odorous frog Odorrana andersonii and determined its effects on ultraviolet B (UVB)-induced skin photodamage as well as its possible molecular mechanisms. Results showed that OA-GI13 directly scavenged free radicals, maintained the viability of hydrogen peroxide-challenged keratinocytes, promoted the release of superoxide dismutase, catalase, and glutathione, and reduced the level of lactate dehydrogenase. Furthermore, topical application of OA-GI13 in mice alleviated dorsal skin erythema and edema and protected the skin against UVB irradiation by increasing antioxidant levels and decreasing peroxide, malondialdehyde, and 8-hydroxydeoxyguanosine levels. OA-GI13 also alleviated oxidative stress injury in vivo and in vitro, possibly by inhibiting p38 protein phosphorylation. Our study confirmed the anti-photodamage effects of this novel amphibian-derived peptide, thus providing a new molecule for the development of drugs and topical agents for the treatment of skin photodamage.

Peptide OM-LV20 promotes structural and functional recovery of spinal cord injury in rats

At present, there are no satisfactory therapeutic drugs for the functional recovery of spinal cord injury (SCI). We previously identified a novel peptide (OM-LV20) that accelerated the regeneration of injured skin tissues of mice and exerts neuroprotective effects against cerebral ischemia/reperfusion injury in rats. Here, the intraperitoneal injection of OM-LV20 (1 μg/kg) markedly improved motor function recovery in the hind limbs of rats with traumatic SCI, and further enhanced spinal cord repair. Administration of OM-LV20 increased the number of surviving neuron bodies, as well as the expression levels of brain-derived neurotrophic factor (BDNF) and its receptor tyrosine receptor kinase B (TrkB). In the acute stage of SCI, OM-LV20 treatment also increased superoxide dismutase and glutathione content but decreased the levels of malonaldehyde and nitric oxide. Thus, OM-LV20 significantly promoted structural and functional recovery of SCI in adult rats by increasing neuronal survival and BDNF and TrkB expression, and thereby regulating the balance of oxidative stress. Based on our knowledge, this research is the first report on the effects of amphibian-derived peptide on the recovery of SCI and our results highlight the potential of peptide OM-LV20 administration in the acceleration of the recovery of SCI.

Amphibian-derived peptide homodimer OA-GL17d promotes skin wound regeneration through the miR-663a/TGF-β1/Smad axis

Background

Amphibian-derived peptides exhibit considerable potential in the discovery and development of new therapeutic interventions for clinically challenging chronic skin wounds. MicroRNAs (miRNAs) are also considered promising targets for the development of effective therapies against skin wounds. However, further research in this field is anticipated. This study aims to identify and provide a new peptide drug candidate, as well as to explore the underlying miRNA mechanisms and possible miRNA drug target for skin wound healing.

Methods

A combination of Edman degradation, mass spectrometry and cDNA cloning were adopted to determine the amino acid sequence of a peptide that was fractionated from the secretion of Odorrana andersonii frog skin using gel-filtration and reversed-phase high-performance liquid chromatography. The toxicity of the peptide was evaluated by Calcein-AM/propidium iodide (PI) double staining against human keratinocytes (HaCaT cells), hemolytic activity against mice blood cells and acute toxicity against mice. The stability of the peptide in plasma was also evaluated. The prohealing potency of the peptide was determined by MTS, scratch healing and a Transwell experiment against HaCaT cells, full-thickness injury wounds and scald wounds in the dorsal skin of mice. miRNA transcriptome sequencing analysis, enzyme-linked immunosorbent assay, real-time polymerase chain reaction and western blotting were performed to explore the molecular mechanisms.

Results

A novel peptide homodimer (named OA-GL17d) that contains a disulfide bond between the 16th cysteine residue of the peptide monomer and the sequence ‘GLFKWHPRCGEEQSMWT’ was identified. Analysis showed that OA-GL17d exhibited no hemolytic activity or acute toxicity, but effectively promoted keratinocyte proliferation and migration and strongly stimulated the repair of full-thickness injury wounds and scald wounds in the dorsal skin of mice. Mechanistically, OA-GL17d decreased the level of miR-663a to increase the level of transforming growth factor-β1 (TGF-β1) and activate the subsequent TGF-β1/Smad signaling pathway, thereby resulting in accelerated skin wound re-epithelialization and granular tissue formation.

Conclusions

Our results suggest that OA-GL17d is a new peptide drug candidate for skin wound repair. This study emphasizes the importance of exogenous peptides as molecular probes for exploring competing endogenous RNA mechanisms and indicates that miR-663a may be an effective target for promoting skin repair.