Li-Hua Peng

The healing and anti-scar effects of astragaloside IV on the wound repair in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCEnAstragaloside IV is the chief ingredient of Radix Astragali, which has been used in the Traditional Chinese Medicine as a major component of many polyherbal formulations for the repair and regeneration of injured organ and tissues. This study is to investigate the influence of astragaloside IV on both of the wound healing and scar formation.nnnMATERIALS AND METHODSnFor the in vitro evaluation, the influence of the astragaloside IV in the wound scratch test of keratinocytes and the secretion of transforming growth factor-β1, a key factor contributing to scar formation were determined. With the rat skin excision model, the in vivo regulation of astragaloside IV on wound closure, angiogenesis and collagen disposition were also evaluated.nnnRESULTSnAstragaloside IV was shown to significantly promote the migration of keratinocytes in wound scratching assay. The superior effect of Astragaloside IV was observed at 100 μmol/L, in which the recover rates was increased with 2 and 3 folds after 48 h and 96 h respectively than that of blank control (P<0.01). Animal skin closure measurement showed that astragaloside IV could stimulate the wound healing, e.g. with 21% recover in contrast to the 8% of blank control at the 6th day. Biomechanic and Massons trichrome stain analysis indicated that astragaloside IV may improve the strength of the repaired skin and promoted the angiogenesis and collagen synthesis. Meanwhile, the picrosirius-sirus red stain and Elisa test definitely showed the anti-scar effects of astragaloside IV by decreasing the levels of collagen I/III and TGF-β1 secretion by firbroblasts with a dose-dependent manner (25-100 μmol/L).nnnCONCLUSIONSnAstragaloside IV was shown a promising natural product with both healing and anti-scar effects for wound treatment. These results give the evidence for the application of astragaloside IV in the treatment of injury.

Silk fibroin/gelatin electrospun nanofibrous dressing functionalized with astragaloside IV induces healing and anti-scar effects on burn wound

Functional wound dressing has provided new challenges for researchers who focus on burn to improve skin graft quality, reduce scarring, and develop a pluristratified dermal or epidermal construct of a burn wound. This study aimed to investigate the effect of a silk fibroin/gelatin (SF/GT) electrospun nanofibrous dressing loaded with astragaloside IV (AS) on deep partial-thickness burn wound. AS-loaded SF/GT-blended nanofibrous dressing was prepared by electrospinning nanotechnology. The optimal ratio (25:75) of silk fibroin to gelatin was further optimized by evaluating ATR-FTIR characteristics, mechanical properties, porosity, swelling rate, degradation, and release profile of the AS-loaded SF/GT nanofibrous dressing. In contrast to the blank control, the AS-loaded SF/GT nanofibrous dressing promoted cell adhesion and proliferation with good biocompatibility in vitro (p<0.01). This dressing also accelerated wound healing and inhibited scar formation in vivo by stimulating wound closure (p<0.05), increasing angiogenesis, regulating newly formed types of collagen, and improving collagen organization. These results showed that SF/GT nanofibrous dressing is a promising topical drug delivery system. Furthermore, AS-functionalized SF/GT nanofibrous dressing is an excellent topical therapeutic that could be applied to promote healing and elicit anti-scar effects on partial-thickness burn wound.

Transcutaneous vaccines: novel advances in technology and delivery for overcoming the barriers.

Transcutaneous immunization represents an attractive alternative to vaccine delivery via topical administration and has received wide attention due to its easy-to-use, needle-free and noninvasive delivery. However, the development of transcutaneous vaccine was kept a challenge because of the barrier function of stratum corneum which inhibits the transport of antigen and adjuvant. Nowadays, pharmaceutical methods and novel physical devices are extensively investigated to overcome the penetration barrier of the stratum corneum for transcutaneous vaccine. In this article, these pharmaceutical methods and novel devices used for the enhancement of transcutaneous immunization were reviewed. In addition, chemokines promoted the migration of Langerhans cells and the transcutaneous adjuvants enhancing the immune responses at certain levels are also discussed for the development of novel transcutaneous vaccines.

Integration of antimicrobial peptides with gold nanoparticles as unique non-viral vectors for gene delivery to mesenchymal stem cells with antibacterial activity

Gold nanoparticles (AuNPs) have emerged as attractive non-viral gene vectors. However their application in regenerative medicine is still limited partially due to a lack of an intrinsic capacity to transfect difficult-to-transfect cells such as primary cells or stem cells. In current study, we report the synthesis of antimicrobial peptide conjugated cationic AuNPs (AuNPs@PEP) as highly efficient carriers for gene delivery to stem cells with antibacterial ability. The AuNPs@PEP integrate the advantages of cationic AuNPs and antibacterial peptides: the presence of cationic AuNPs can effectively condense DNA and the antimicrobial peptides are essential for the cellular & nucleus entry enhancement to achieve high transfection efficiency and antibacterial ability. As a result, antimicrobial peptides conjugated AuNPs significantly promoted the gene transfection efficiency in rat mesenchymal stem cells than pristine AuNPs, with a similar extent to those expressed by TAT (a well-known cell-penetrating peptide) modified AuNPs. More interestingly, the combinational system has better antibacterial ability than free antimicrobial peptides inxa0vitro and inxa0vivo, possibly due to the high density of peptides on the surface of AuNPs. Finally we present the concept-proving results that AuPs@PEP can be used as a carrier for inxa0vivo gene activation in tissue regeneration, suggesting its potential as a multifunctional system with both gene delivery and antibacterial abilities in clinic.

Astragaloside IV-loaded nanoparticle-enriched hydrogel induces wound healing and anti-scar activity through topical delivery

This study aims to investigate the novel preparation of solid lipid nanoparticle-enriched hydrogel (SLN-gel) for the topical delivery of astragaloside IV and to determine the effects of astragaloside IV-based SLN-gel on wound healing and anti-scar formation. Solid lipid nanoparticles (SLNs) were prepared through the solvent evaporation method. The particle size, polydispersity index (PDI), zeta potential (ZP), encapsulation efficiency (EE), drug release, and morphological properties of the SLNs were characterized. The optimized SLNs were incorporated in carbomer hydrogel to form an SLN-enriched gel (SLN-gel) carrier. The effects of astragaloside IV-enriched SLNs on wound healing were determined using the wound scratch test, and their uptake by skin cells was tested in vitro. With the rat full-skin excision model, the in vivo regulation of astragaloside IV-based SLN-gel in the wound stages of re-epithelization, angiogenesis, and extracellular matrix remodeling was investigated. The best formulation of astragaloside IV-based SLNs had high EE (93% ± 5%) and ZP (-23.6 mV ± 1.5 mV), with a PDI of 0.18 ± 0.03 and a drug loading percentage of 9%. Astragaloside IV-based SLNs and SLN-gel could release drug sustainably. Astragaloside IV-based SLNs enhanced the migration and proliferation of keratinocytes and increased drug uptake on fibroblasts in vitro (P<0.01) through the caveolae endocytosis pathway, which was inhibited by methyl-β-cyclodextrin. Astragaloside IV-based SLN-gel strengthened wound healing and inhibited scar formation in vivo by increasing wound closure rate (P<0.05) and by contributing to angiogenesis and collagen regular organization. SLN-enriched gel is a promising topical drug delivery system. Astragaloside IV-loaded SLN-enriched gel was proven as an excellent topical preparation with wound healing and anti-scar effects.

TAT conjugated cationic noble metal nanoparticles for gene delivery to epidermal stem cells.

Most nonviral gene delivery systems are not efficient enough to manipulate the difficult-to-transfect cell types, including non-dividing, primary, neuronal or stem cells, due to a lack of an intrinsic capacity to enter the membrane and nucleus, release its DNA payload, and activate transcription. Noble metal nanoclusters have emerged as a fascinating area of widespread interest in nanomaterials. Herein, we report the synthesis of the TAT peptide conjugated cationic noble metal nanoparticles (metal NPs@PEI-TAT) as highly efficient carriers for gene delivery to stem cells. The metal NPs@PEI-TAT integrate the advantages of metal NPs and peptides: the presence of metal NPs can effectively decrease the cytotoxicity of cationic molecules, making it possible to apply them in biological systems, while the cell penetrating peptides are essential for enhanced cellular and nucleus entry to achieve high transfection efficiency. Our studies provide strong evidence that the metal NPs@PEI-TAT can be engineered as gene delivery agents for stem cells and subsequently enhance their directed differentiation for biomedical application.

Inhibitory effects of salidroside and paeonol on tyrosinase activity and melanin synthesis in mouse B16F10 melanoma cells and ultraviolet B-induced pigmentation in guinea pig skin

Salidroside, the major active component of Rhodiola rosea, a herb with antioxidant, free radical scavenging and tyrosinase inhibitory effects, has been recently reported in protecting the kerationcytes from the UV radiation, suggesting the potential of this component in depigmentation. Paeonol is isolated from Moutan Cortex Radicis with anti-inflammation/microbial activities, was reported to induce the down-regulation of microphthalmia-associated transcription factor and subsequently tyrosinase. To testify the potential of these compounds as melanin formation inhibitors for hyperpigmentation therapy, the influence of salidroside and paeonol on pigmentation was investigated. With arbutin as a positive control, salidroside and paeonol were evaluated for their inhibitory effect on the cell viability, tyrosinase activity and melanin synthesis in B16F10 melanoma cells, as well as their effects in UVB-induced hyperpigmentation in brown guinea pig skins. It was demonstrated that the significant inhibition of salidroside (33.0%) and paeonol (22.2-30.9%) on the tyrosinase activity is slightly lower than that of arbutin (18.4-44.7%). However, salidroside exhibited the dose-dependent inhibition (30.6-42.0%) in melanin synthesis at a low concentration of 100 μM, paeonol and arbutin expressed inhibition rates of 27.4-37.2% and 25.8-45.6% within 500-1000 μM. The in vivo topical application of these compounds was demonstrated to obviously decrease the hyperpigmentation on UVB stimulated guinea pig skin. This study provided the original evidence for the salidroside and paeonol as therapeutic agents for pigmentation disorder and skin lightening, with further clinical investigation of these compounds in the field of depigmentation was suggested.

Effective transcutaneous immunization by antigen-loaded flexible liposome in vivo

Background Transcutaneous vaccines have received wide attention due to their easy-to-use, needle-free, noninvasive delivery. However, the novel barrier function of stratum corneum hinders the transport of antigen and adjuvant in transcutaneous immunization. Novel nanoscale delivery systems employing, for example, liposomes and nanoparticles, have been widely investigated to overcome the penetration barrier of stratum corneum for effective transcutaneous immunization. Objective The objective of this study was to prepare two types of flexible liposomes and determine their efficacies for the transcutaneous delivery of antigen and the subsequent immune response induced in vivo. Methods Ovalbumin (OVA) liposome-based transcutaneous vaccines were prepared using reverse-phase evaporation and film-dispersion methods. Particle sizes and antigen encapsulating efficiency were then evaluated. After application to bare mouse skin, topical sites were examined for the presence of fluorescence-labeled liposome. The efficacy of the transcutaneously delivered OVA-loaded flexible liposome in activating the immune responses was investigated by detecting serum immunoglobulin G levels. The influence of an adjuvant, imiquimod, in the transcutaneous immunization was also tested. Results Two flexible liposomes with well-encapsulated OVA were successfully prepared by film-dispersion or reverse-phase evaporation methods. The sizes of the prepared flexible liposomes ranged from 200 to 400 nm. In vivo, the fluorescence-labeled liposome was detected in hair-follicle ducts, indicating that the flexible liposome can penetrate the skin barrier through the hair follicles. Upon transcutaneous administration, the OVA-encapsulated flexible liposome elicited a strong immune response similar to that of positive control (ie, OVA solution administrated by subcutaneous injection with Al(OH)3 as an adjuvant). Co-administration of imiquimod with the OVA-loaded liposome expressed a significant enhancement on the transcutaneous immune responses. Conclusion Results of this study highlight the nanoscale formulation, flexible liposome, as a promising carrier for the transcutaneous delivery of antigen proteins. Imiquimod was shown to be an effective adjuvant as a transcutaneous immunization enhancer with the potential for transcutaneous vaccine development.

Cell Membrane Capsules for Encapsulation of Chemotherapeutic and Cancer Cell Targeting in Vivo.

Systemic administration of chemotherapeutic agents can cause indiscriminate drug distribution and severe toxicity. Until now, encapsulation and targeting of drugs have typically relied on synthetic vehicles, which cannot minimize the clearance by the renal system and may also increase the risk of chemical side effects. Cell membrane capsules (CMCs) provide a generic and far more natural approach to the challenges of drug encapsulation and delivery in vivo. Here aptamer AS1411, which can recognize and bind overexpressed nucleolin on a cancer cell membrane, was chemically conjugated onto CMCs. As a result, AS1411 modified CMCs showed enhanced ingestion in certain cancer cells in vitro and accumulation in mouse cancer xenografts in vivo. Chemotherapeutics and contrast agents with therapeutically significant concentrations can be packaged into CMCs by reversible permeating their plasma membranes. The systematic administration of cancer targeting CMCs loaded with doxorubicin hydrochloride can significantly inhibit tumor growth in mouse xenografts, with significantly reduced toxicity compared to free drug. These findings suggest that cancer targeting CMCs may have considerable benefits in drug delivery and cancer treatment.

Antigen-loaded nanocarriers enhance the migration of stimulated Langerhans cells to draining lymph nodes and induce effective transcutaneous immunization

UNLABELLEDnThis study aims to investigate the efficacy of chitosan nanoparticles (CS-NPs) as a vehicle for transcutaneous antigen delivery in anti-tumor therapy. Ovalbumin (OVA) or gp100 (melanocyte-associated antigen gp100 protein)-loaded CS-sodium tripolyphosphate (TPP)-grafted NPs were prepared by crosslinking low-molecular-weight CS with TPP. Compared with the FITC-OVA solution, the encapsulated fluorescein isothiocyanate (FITC)-OVA-loaded NPs expressed much stronger cellular uptake ability in vitro and higher ability to migrate to lymph nodes in vivo. After transcutaneous administration, OVA-loaded NPs, with imiquimod as an adjuvant, increased the anti-OVA immunoglobulin G titer to levels similar to those induced by the OVA solution. The gp100-loaded NPs promoted the survival of tumor-bearing mice. These results provided evidence of CS-NPs as promising carriers for transcutaneous vaccine delivery, partly contributing to the increased uptake of NPs by skin antigen-presenting cells as well as their enhanced migration to the surrounding lymph nodes.nnnFROM THE CLINICAL EDITORnIn this study the efficacy of chitosan nanoparticle based vehicles for transcutaneous antigen delivery is investigated in anti-tumor therapy. Authors demonstrate that such nanoparticles may be efficient carriers partly due to their increased uptake by antigen-presenting cells in the skin and their enhanced migration to surrounding lymph nodes.