A new nanoscale transdermal drug delivery system: oil body-linked oleosin-hEGF improves skin regeneration to accelerate wound healing

An Immune-Regulating Polysaccharide Hybrid Hydrogel with Mild Photothermal Effect and Anti-Inflammatory for Accelerating Infected Wound Healing

Bacterial infections and excessive inflammation present substantial challenges for clinical wound healing. Hydrogels with mild photothermal (PTT) effects have emerged as promising agents owing to their dual actions: positive effects on cells and negative effects on bacteria. Here, an injectable self-healing hydrogel of oxidized konjac glucomannan/arginine-modified chitosan (OKGM/CS-Arg, OC) integrated with protocatechualdehyde-@Fe (PF) nanoparticles capable of effectively absorbing near-infrared radiation is synthesized successfully. The OC/PF hydrogels exhibit excellent mechanical properties, biocompatibility, and antioxidant activity. Moreover, in synergy with PTT, OC/PF demonstrates potent antibacterial effects while concurrently stimulating cell migration and new blood vessel formation. In methicillin-resistant Staphylococcus aureus-infected full-thickness mouse wounds, the OC/PF hydrogel displays remarkable antibacterial and anti-inflammatory activities, and accelerates wound healing by regulating the wound immune microenvironment and promoting M2 macrophage polarization. Consequently, the OC/PF hydrogel represents a novel therapeutic approach for treating multidrug-resistant bacterial infections and offers a technologically advanced solution for managing infectious wounds in clinical settings.

Long duration sodium hyaluronate hydrogel with dual functions of both growth prompting and acid-triggered antibacterial activity for bacteria-infected wound healing

Conventional wound dressings are monolithically designed to cover the injured areas as well as absorb the exudates at injured site. Furthermore, antibacterial drugs and growth prompting factors are additionally appended to realize sensible and omnibearing wound management, exhibiting long and tedious treatment process in practice. Consequently, the creation of multifunctional wound dressings that combines wound repair enhancement with antibacterial properties turns out to be significant for simplifying wound managements. In our investigation, electronegative human epidermal growth factor (hEGF) was combined with the positively charged Zn-Al layered double hydroxides (Zn-Al LDHs) via electrostatic interaction while the obtained hEGF/LDH was integrated with sodium hyaluronate hydrogel (SH) hydrogel, forming a composite hydrogel with synergistic benefits for wound management. The innovative hEGF/LDH@SH hydrogel equipped with fine biocompatibility was designed to optimize wound healing in which hEGF stimulates epithelial cell growth while LDH released antibacterial factor Zn2+ against Methicillin-resistant staphylococcus aureus (MRSA) and Escherichia coli (E.coli) under acidic wound environment. Additionally, the SH hydrogel constructed a three-dimensional structure that not only safeguarded the wound area but also maintained a moist environment conducive to recovery. The synthesized hEGF/LDH was confirmed via fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and thermo-gravimetry (TG) measurements. The release of Zn2+ from Zn-Al LDH under acid circumstance was detected via inductively coupled plasma (ICP) and the in vitro bactericidal experiments endowed the antibacterial property of hEGF/LDH@SH hydrogel. In vitro drug release experiments illustrated the controlled-release of hEGF from hEGF/LDH which promoted the long-term affect of hEGF at wound site. In vitro cell experiments verified that the hEGF/LDH@SH hydrogel motivated the promotion on cell proliferation and migration without cytotoxicity. An in vivo study of the repairing of MRSA-infected wound in mice indicated that hEGF/LDH@SH hydrogel serves as a simple and novel, innoxious and efficient wound healing approach. This brand new hydrogel possesses properties of promoting the regeneration of skin tissue, achieving antimicrobial therapy without any accessional antibacterial drugs as well as realizing controlled release of hEGF.

Cellular organelles as drug carriers for disease treatment

Organelles not only constitute the basic structure of the cell but also are important in maintaining the normal physiological activities of the cell. With the development of biomimetic nanoscience, researchers have developed technologies to use organelles as drug carriers for disease treatment. Compared with traditional drug carriers, organelle drug carriers have the advantages of good biocompatibility, high drug loading efficiency, and modifiability, and the surface biomarkers of organelles can also participate in intracellular signal transduction to enhance intracellular and intercellular communication, and assist in enhancing the therapeutic effect of drugs. Among different types of organelles, extracellular vesicles, lipid droplets, lysosomes, and mitochondria have been used as drug carriers. This review briefly reviews the biogenesis, isolation methods, and drug-loading methods of four types of organelles, and systematically summarizes the research progress in using organelles as drug-delivery systems for disease treatment. Finally, the challenges faced by organelle-based drug delivery systems are discussed. Although the organelle-based drug delivery systems still face challenges before they can achieve clinical translation, they offer a new direction and vision for the development of next-generation drug carriers.

Freeze-Dried Camelina Lipid Droplets Loaded with Human Basic Fibroblast Growth Factor-2 Formulation for Transdermal Delivery: Breaking through the Cuticle Barrier to Accelerate Deep Second-Degree Burn Healing

Transdermal administration of chemo therapeutics into burn healing may be an effective treatment to reduce toxic side effects and improve patient compliance for burns. As a transdermal delivery system, Camelina lipid droplets (CLDs) have received great attention due to their biocompatibility, high drug payload, and rapid absorption. However, the absorbed-related mechanisms of Camelina lipid droplets have not yet been reported. Thus, this paper not only demonstrated that CLD can accelerate skin burn healing through promoting hFGF2 absorption, but also elucidated the mechanism between the skin tissue and keratinocytes using Franz, HE staining, DSC, FTIR spectroscopy, and atomic force microscopy with the presence of CLD-hFGF2 freeze-dried powder. We found that the cumulative release rate of CLD-hFGF2 freeze-dried powder was significantly higher than that of free hFGF2 freeze-dried powder into the skin. At the same time, CLD can change the structure and content of lipids and keratin to increase the permeability of hFGF2 freeze-dried powder in skin tissue. Unlike the free state of hFGF2, the biophysical properties of single cells, including height and adhesion force, were changed under CLD-hFGF2 freeze-dried powder treatment. Meanwhile, CLD-hFGF2 freeze-dried powder was more easily taken up through keratinocytes without damaging cell integrity, which provided a new viewpoint for understanding the absorption mechanism with the CLD system for cellular physiology characteristics. Overall, our findings demonstrated that CLD could break through the stratum corneum (SC) barrier and elucidated the transport mechanism of lipid droplets in skin tissue, which provides a crucial guideline in drug delivery applications for future engineering.

The establishment of transient expression systems and their application for gene function analysis of flavonoid biosynthesis in Carthamus tinctorius L

BACKGROUND

Safflower (Carthamus tinctorius L.) is an important economic crop and a traditional medicinal material rich in flavonoids, which can alleviate cardiovascular and cerebrovascular pathologies. Thus, many candidate genes involved in safflower flavonoid biosynthesis have been cloned. However, owing to the lack of a homologous gene expression system, research on gene function is limited to model plants. Therefore, a gene function identification protocol for safflower must be established.

RESULTS

In the present study, using safflower callus as the experimental material, Agrobacterium and biolistic transient expression systems were established. In the Agrobacterium transient expression system, the highest transformation rate was obtained at the original Agrobacterium concentration of OD600 0.4, infiltration concentration of OD600 0.6, infection for 20 min, co-culture for 3 days, and acetosyringone concentration of 100 μmol·L-1. In the biolistic transient expression system, the highest transformation efficiency was observed at helium pressure of 1,350 psi, vacuum degree of -0.8 bar, flight distance of 6.5 cm, one round of bombardment, plasmid concentration of 3 μg·shot-1, and gold particle concentration of 100 μg·shot-1. Further, these two transient expression systems were used for the functional analysis of CtCHS1 as an example. After overexpression, relative CtCHS1 expression increased, particularly in Agrobacterium-transformed calli. Additionally, the contents of some flavonoids were altered; for instance, naringenin and genistein levels were significantly increased in Agrobacterium-transformed calli, whereas luteolin, luteolin-7-O-rutinoside, and apigenin derivative levels were significantly decreased in biolistic-transformed calli.

CONCLUSION

Using safflower callus as the experimental material, highly efficient Agrobacterium and biolistic transient expression systems were successfully established, and the utility of both systems for investigating gene function was demonstrated. The proposed safflower callus transient expression systems will be useful for further functional analyses of flavonoid biosynthetic genes in safflower.

Recombinant Oil-Body-Expressed Oleosin-hFGF5 in Arabidopsis thaliana Regulates Hair Growth

FGF5 (Fibroblast Growth Factor) is a member of the fibroblast growth factor family, which not only regulates growth and development but also inhibits hair regeneration. The oil-body expression vector pOTB-hFGF5 was constructed by the genetic engineering method and it was transformed into Arabidopsis by flora dip. T3 homozygous transgenic Arabidopsis was obtained after screening and propagation by the PCR and Western blot methods. The recombinant oil-body-expressed oleosin-hFGF5 can inhibit the proliferation of hair follicle epithelial cells and it exhibits the pharmacological activity of inhibiting hair regeneration in vivo by protein hybridization and imunohistochemistry. At the same time, the potential mechanism of recombinant oil-body-expressed oleosin-hFGF5 inhibiting hair growth was also revealed by RNA-Seq. This implies that the recombinant oil-body-expressed oleosin-hFGF5 has a good effect on inhibiting hair growth.

Xanthan gum/oil body-microgel emulsions with enhanced transdermal absorption for accelerating wound healing

The oil body comprises lipid droplets surrounded by a surface embedded with oil body-related proteins. To form a drug delivery system, an oleosin can be fused with foreign proteins and bound to the oil body surface. Here, safflower oil bodies carrying oleosin-human epidermal growth factor (hEGF) were mixed with xanthan gum to form self-assembled polymers, referred as an oil body microgel emulsion (OBEME) without any chemical crosslinking agent. The physicochemical properties of OBEME were evaluated and compared with those of natural lipid droplets. The electrostatic interaction between xanthan gum and oil bodies prevents excessive cross-linking and forms a uniform network structure. The basic properties of OBEME were characterized by scanning electron microscopy, cryo-scanning electron microscopy, rheology, and thermogravimetric analysis. The OBEME is an interconnected network and presents a smooth surface without any pores; it remains stable at room temperature for 90 days, and is not affected by low-speed centrifugation and repeated freeze-thaw cycles as indicated by particle size, potential, and fluorescence microscopy analyses. The OBEME enlarges the skin tissue gap, enhances skin permeability, and shows a good slow-release effect in the transdermal absorption test in vivo. It demonstrates a wound healing effect; further, it regulates the inflammatory response of full-layer skin wounds in rats, as well as accelerate angiogenesis, and promote re-epithelialization and remodeling. The OBEME as a bioactive molecule-carbohydrate complex can effectively accelerate skin regeneration and has great translational potential to provide low-cost alternative wound care treatments.

Roles of the Exosomes Derived From Myeloid-Derived Suppressor Cells in Tumor Immunity and Cancer Progression

Tumor immunity is involved in malignant tumor progression. Myeloid-derived suppressor cells (MDSCs) play an irreplaceable role in tumor immunity. MDSCs are composed of immature myeloid cells and exhibit obvious immunomodulatory functions. Exosomes released by MDSCs (MDSCs-Exos) have similar effects to parental MDSCs in regulating tumor immunity. In this review, we provided a comprehensive description of the characteristics, functions and mechanisms of exosomes. We analyzed the immunosuppressive, angiogenesis and metastatic effects of MDSCs-Exos in different tumors through multiple perspectives. Immunotherapy targeting MDSCs-Exos has demonstrated great potential in cancers and non-cancerous diseases.

Biophysical characterization of full-length oleosin in dodecylphosphocholine micelles

Oleosin is a hydrophobic protein that punctuates the surface of plant seed lipid droplets, which are 20 nm-100 μm entities that serve as reservoirs for high-energy metabolites. Oleosin is purported to stabilize lipid droplets, but its exact mechanism of stabilization has not been established. Probing the structure of oleosin directly in lipid droplets is challenging due to the size of lipid droplets and their high degree of light scattering. Therefore, a medium in which the native structure of oleosin is retained, but is also amenable to spectroscopic studies is needed. Here, we show, using a suite of biophysical techniques, that dodecylphosphocholine micelles appear to support the tertiary structure of the oleosin protein (i.e., hairpin conformation) and render the protein in an oligomeric state that is amenable to more sophisticated biophysical techniques such as NMR.

Optimization of the extraction conditions and dermal toxicity of oil body fused with acidic fibroblast growth factor (OLAF)

INTRODUCTION

Oil body (OB), a subcellular organelle that stores oil in plant seeds, is considered a new transdermal drug delivery system. With the increasing understanding of the OB and its main protein (oleosin), numerous studies have been conducted on OB as "carrier" for the expression of exogenous proteins. In our previous study, oil body fused with aFGF (OLAF) was obtained using a plant oil body expression system that had been preliminarily proven to be effective in accelerating the healing of skin wounds. However, no dermal toxicological information on OLAF is available.

OBJECTIVE

To ensure the dermal safety of OLAF, a series of tests (the acute dermal toxicity test, 21-day repeat dermal toxicity test, dermal irritation test and skin sensitisation test) were conducted after optimising the extraction protocol of OLAF.

MATERIALS AND METHODS

To improve the extraction rate of OLAF, response surface methodology (RSM) was first employed to optimise the extraction conditions. Then, Wistar rats were exposed to OLAF (400 mg·kg^-1 body weight) in two different ways (6 hours/time for 24 hours and 1 time/day for 21 days) to evaluate the acute dermal toxicity and 21-day repeated dermal toxicity of OLAF. In the acute dermal toxicity test, clinical observations were conducted to evaluate the toxicity, behaviour, and health of the animals for 14 consecutive days. Similarly, the clinical signs, body weight, haematological and biochemical parameters, histopathological changes and other indicators were also detected during the 21 days administration. For the dermal irritation test, single and multiple doses of OLAF (125 mg·kg^-1 body weight) were administered to albino rabbits for 14 days (1 time/day). The irritation reaction on the skin of each albino rabbit was recorded and scored. Meanwhile, skin sensitisation to OLAF was conducted using guinea pigs for a period of 28 days.

RESULTS

Suitable extraction conditions for OLAF (PBS concentration 0.01, pH of PBS 8.6, solid-liquid ratio 1:385 g·mL^-1) were obtained using RSM. Under these conditions, the extraction rate and particle size of OLAF were 7.29% and 1290 nm, respectively. In the tests of acute dermal toxicity and 21-day repeated dermal toxicity, no mortality or significant differences were observed in terms of clinical signs, body weight, haematological parameters, biochemical parameters and anatomopathological analysis. With respect to the dermal irritation test and skin sensitisation test, no differences in erythema, oedema or other abnormalities were observed between treatment and control groups on gross and histopathological examinations.

CONCLUSIONS

The results of this study suggest that OLAF does not cause obvious toxicity, skin sensitisation or irritation in animals.

Exosomes derived from pioglitazone-pretreated MSCs accelerate diabetic wound healing through enhancing angiogenesis

BACKGROUND

Enhanced angiogenesis can promote diabetic wound healing. Mesenchymal stem cells (MSCs)-derived exosomes, which are cell-free therapeutics, are promising candidates for the treatment of diabetic wound healing. The present study aimed to investigate the effect of exosomes derived from MSCs pretreated with pioglitazone (PGZ-Exos) on diabetic wound healing.

RESULTS

We isolated PGZ-Exos from the supernatants of pioglitazone-treated BMSCs and found that PGZ-Exos significantly promote the cell viability and proliferation of Human Umbilical Vein Vascular Endothelial Cells (HUVECs) injured by high glucose (HG). PGZ-Exos enhanced the biological functions of HUVECs, including migration, tube formation, wound repair and VEGF expression in vitro. In addition, PGZ-Exos promoted the protein expression of p-AKT, p-PI3K and p-eNOS and suppressed that of PTEN. LY294002 inhibited the biological function of HUVECs through inhibition of the PI3K/AKT/eNOS pathway. In vivo modeling in diabetic rat wounds showed that pioglitazone pretreatment enhanced the therapeutic efficacy of MSCs-derived exosomes and accelerated diabetic wound healing via enhanced angiogenesis. In addition, PGZ-Exos promoted collagen deposition, ECM remodeling and VEGF and CD31 expression, indicating adequate angiogenesis in diabetic wound healing.

CONCLUSIONS

PGZ-Exos accelerated diabetic wound healing by promoting the angiogenic function of HUVECs through activation of the PI3K/AKT/eNOS pathway. This offers a promising novel cell-free therapy for treating diabetic wound healing.

Preparation and characterization of neutrally-buoyant oleosin-rich synthetic lipid droplets

Lipid droplets also known as oil bodies are found in a variety of organisms and function as stores of high-energy metabolites. Recently, there has been interest in using lipid droplets for protein production and drug delivery. Artificial lipid droplets have been previously prepared, but their short lifetime in solution and inhomogeneity has severely limited their applicability. Herein we report an improved methodology for the production of synthetic lipid droplets that overcomes the aforementioned limitations. These advancements include: 1) development of a methodology for the expression and purification of high-levels of oleosin, a crucial lipid droplet component, 2) preparation of neutrally-buoyant synthetic lipid droplets, and 3) production of synthetic lipid droplets of a specific size. Together, these important enhancements will facilitate the advancement of lipid droplet science and its application in biotechnology.

Microparticles and Nanoparticles from Plants-The Benefits of Bioencapsulation

The efficacy of drugs and vaccines depends on their stability and ability to interact with their targets in vivo. Many drugs benefit from encapsulation, which protects them from harsh conditions and allows targeted delivery and controlled release. Although many encapsulation methods are inexpensive, such as the formulation of tablets for oral delivery, others require complex procedures that add significantly to production costs and require low-temperature transport and storage, making them inaccessible in developing countries. In this review we consider the benefits of encapsulation technologies based on plants. Plant-derived biopolymers such as starch and the maize storage protein zein are already used as protective coatings, but plant cells used as production host provide natural in vivo bioencapsulation that survives passage through the stomach and releases drugs in the intestine, due to the presence of microbes that can digest the cell wall. Proteins can also be encapsulated in subcellular compartments such as protein bodies, which ensure stability and activity while often conferring additional immunomodulatory effects. Finally, we consider the incorporation of drugs and vaccines into plant-derived nanoparticles assembled from the components of viruses. These are extremely versatile, allowing the display of epitopes and targeting peptides as well as carrying cargoes of drugs and imaging molecules.

Dermal toxicity, dermal irritation, and delayed contact sensitization evaluation of oil body linked oleosin-hEGF microgel emulsion via transdermal drug delivery for wound healing

Objective: The expression of therapeutic proteins in plant oil body bioreactors has attracted much attention. But its safety is not yet clear. This article determines the risk of safety after using the drug. Methods: The oil body-linked oleosin-hEGF microgel emulsion (OBEME) was prepared by mixing the xanthan gum with suitable concentrations in an appropriate proportion. Skin irritation and sensitization reaction were investigated in rats and guinea pigs using OBEME as test article.Results: The OBEME did not produce dermal erythema/eschar or oedema responses. The dermal subacute and subchronic toxicity of OBEME were evaluated in accordance with OECD guidelines. Compared with the control group, the basic physical signs, such as weight, feed, drinking, excretion, and behaviour of experimental animals, were not abnormal. In addition, no abnormality was found in haematological parameters, biochemical indexes, relative organ weight, and histopathological observation of organs, and there was no significant difference compared with normal saline treatment group. Therefore, we conclude that OBEME has no toxic effects and is safe and reliable to be used for topical application.

Expression, purification and functional identification of the modified hEGF protein

Human epidermal growth factor (hEGF) plays an important role in the growth and division of epithelial cells and has good application prospects in skin-related injuries and diseases. Weak skin penetration and rapid clearance of hEGF in skin via the mononuclear phagocyte system have restricted the application of hEGF. To overcome these shortcomings, the recombinant gene TAT-hEGF-CD47 was constructed in our experiments, and the fusion protein TAT-hEGF-CD47 was expressed, purified and renatured. The cell proliferation-promoting function, skin penetration and concentration of TAT-hEGF-CD47 in skin after its application were determined. The results showed that TAT-hEGF-CD47 effectively promoted human skin fibroblast and skin epithelial cell proliferation, and the proliferation-promoting effect was positively correlated with the TAT-hEGF-CD47 concentration. After administration to the skin, TAT-hEGF-CD47 effectively penetrated the epidermal layer of the skin because of the TAT domain and stayed in the skin for a long time because the CD47 fragment slowed its clearance via the mononuclear phagocytic system. In conclusion, TAT-hEGF-CD47 exhibits high cell proliferation-promoting activity, high skin penetration efficiency and long retention time in skin and has laid the foundation for its wide application in skin repair, ulcer, diabetes and even cancer treatments.

Molecular Pharming of the Recombinant Protein hEGF-hEGF Concatenated with Oleosin Using Transgenic Arabidopsis

We set out to assess the NIH/3T3 cell proliferation activity of Arabidopsis oil body-expressed recombinant oleosin–hEGF–hEGF protein. Normally, human epidermal growth factor (hEGF) is purified through complex process, however, oleosin fusion technology provides an inexpensive and scalable platform for its purification. Under a phaseolin promoter, we concatenated oleosin gene to double hEGF (hEGF–hEGF) with plant-preferred codons in the expression vectors and the construct was transformed into Arabidopsis thaliana (Arabidopsis). The transgenic Arabidopsis was validated by RT–PCR and the content of recombinant protein oleosin–hEGF–hEGF was quantified by western blot. Subsequently, the proliferation assay and transdermal absorption were determined by MTT method and immunohistochemical staining, respectively. First, the expression level of hEGF was recorded to be 14.83-ng/μL oil body and due to smaller size transgenic oil bodies expressing the recombinant oleosin–hEGF–hEGF, they were more skin permeable than those of control. Second, via the staining intensity of transgenic oil bodies was greater than EGF at all time points via immunohistochemical staining in transdermal absorption process. Lastly, activity assays of oil bodies expressed oleosin–hEGF–hEGF indicated that they stimulated the NIH/3T3 cell proliferation activity. Our results revealed oil-body-expressed oleosin–hEGF–hEGF was potential new material having implications in the field of medicine.

Transdermal delivery of Minoxidil using HA-PLGA nanoparticles for the treatment in alopecia

BACKGROUND

Alopecia has become a very common disease that many people around the world are suffered. Minoxidil (MXD) is the most well-known commercialized drug in its treatment. However, in the case of MXD administration, there are some problems with low efficiency of transdermal delivery and additional side effects.

METHOD

MXD and Rhodamine B (Rho B) are encapsulated in poly(Lactide-co-Glycolide) grafted hyaluronate nanoparticles (HA-PLGA/MXD NPs, HA-PLGA/Rho B NPs) which is prepared with W/O/W solvent evaporation method. After then, the investigation is carried out to confirm the feasibility of NPs in alopecia treatment.

RESULTS

Both of HA-PLGA/MXD NPs and HA-PLGA/Rho B NPs are successfully prepared. In addition, it is confirmed that HA-PLGA NPs sufficiently delivered to cells without any significant cytotoxicity by cell viability, cellular uptake and skin permeation test.

CONCLUSION

Taken together, HA-PLGA NPs as a transdermal delivery carrier to hair follicle cells can be exploited to develop the efficient and effective platform of transdermal drug delivery for the treatment of various diseases.