RNAi mediated IL-6 in vitro knockdown in psoriasis skin model with topical siRNA delivery system based on liquid crystalline phase

Nanotechnology strategies to address challenges in topical and cellular delivery of siRNAs in skin disease therapy

Gene therapy is one of the most advanced therapies in current medicine. In particular, interference RNA-based therapy by small interfering RNA (siRNA) has gained attention in recent years as it is a highly versatile, selective and specific therapy. In dermatological conditions, topical delivery of siRNA offers numerous therapeutic advantages, mainly by inhibiting the expression of target transcripts directly in the skin. However, crossing the stratum corneum and overcoming intracellular barriers is an inherent challenge. Substantial efforts by scientists have moved towards the use of multimodal and multifunctional nanoparticles to overcome these barriers and achieve greater bioavailability in their site of action, the cytoplasm. In this review the most innovative strategies based on nanoparticle and physical methods are presented, as well as the design principles and the main factors that contribute to the performance of these systems. This review also highlights the synergistic contributions of medicine, nanotechnology, and molecular biology to advancing translational research into siRNA-based therapeutics for skin diseases.

Solid Lipid-Polymer Hybrid Nanoplatform for Topical Delivery of siRNA: In Vitro Biological Activity and Permeation Studies

Small interfering RNA (siRNA) molecules have limited transfection efficiency and stability, necessitating the use of delivery systems to be effective in gene knockdown therapies. In this regard, lipid-polymeric nanocarriers have emerged as a promising class of nanoparticles for siRNA delivery, particularly for topical applications. We proposed the use of solid lipid-polymer hybrid nanoparticles (SLPHNs) as topical delivery systems for siRNA. This approach was evaluated by assessing the ability of SLPHNs-siRNA complexes to internalize siRNA molecules and both to penetrate skin layers in vitro and induce gene knocking down in a skin cell line. The SLPHNs were formed by a specific composition of solid lipids, a surfactant polymer as a dispersive agent, and a cationic polymer as a complexing agent for siRNA. The optimized nanocarriers exhibited a spherical shape with a smooth surface. The average diameter of the nanoparticles was found to be 200 nm, and the zeta potential was measured to be +20 mV. Furthermore, these nanocarriers demonstrated excellent stability when stored at 4 °C over a period of 90 days. In vitro and in vivo permeation studies showed that SLPHNs increased the cutaneous penetration of fluorescent-labeled siRNA, which reached deeper skin layers. Efficacy studies were conducted on keratinocytes and fibroblasts, showing that SLPHNs maintained cell viability and high cellular uptake. Furthermore, SLPHNs complexed with siRNA against Firefly luciferase (siLuc) reduced luciferase expression, proving the efficacy of this nanocarrier in providing adequate intracellular release of siRNA for silencing specific genes. Based on these results, the developed carriers are promising siRNA delivery systems for skin disease therapy.

Liquid crystalline nanoparticles enable a multifunctional approach for topical psoriasis therapy by co-delivering triptolide and siRNAs

Liquid crystalline nanoparticles (LCNs) are an attractive drugs topical delivery system due to the great internal ordering, wide interfacial area and structural similarities with the skin. In this work, LCNs were designed to encapsulate triptolide (TP) and to complex on its surface small interfering RNAs (siRNA) targeting TNF-α and IL-6, aiming at topical co-delivery and regulating multi-targets in psoriasis. These multifunctional LCNs showed appropriate physicochemical properties for topical application, such as a mean size of 150 nm, low polydispersion, TP encapsulation greater than 90% and efficient complexation with siRNA. The internal reverse hexagonal mesostructure of LCNs was confirmed by SAXS while their morphology was assessed by cryo-TEM. In vitro permeation studies revealed an increase of more than 20-fold in the distribution of TP through the porcine epidermis/dermis was achieved after the application of LCN-TP or LCN TP in hydrogel. In cell culture, LCNs showed good compatibility and rapid internalization, which was attributed to macropinocytosis and caveolin-mediated endocytosis. Anti-inflammatory potential of multifunctional LCNs was assessed by reducing of TNF-α, IL-6, IL-1β and TGF-β1 levels in LPS-stimulated macrophages. These results support the hypothesis that the co-delivery of TP and siRNAs by LCNs may be a new strategy for psoriasis topical therapy.

Triton modified polyethyleneimine conjugates assembled with growth arrest-specific protein 6 for androgenetic alopecia transdermal gene therapy

Androgenetic alopecia is an androgen-dependent skin disorder that commonly affects hair follicle growth and hair loss. Gene therapy that can promote the proliferation and survival of hair follicle cells can be a potential choice for its cure. While transdermal application of therapeutic functional nucleic acids across the stratum corneum is quite difficult. Here, we first develop a transdermal agent for functional nucleic acid delivery using Triton X-100-modified low molecular weight polyethyleneimine (PEI-Triton-N, N ​= ​6 or 8). In vitro cell experiments demonstrate that the PEI-Triton-N conjugates can stably encapsulate and efficiently deliver plasmid DNA to hard-to-transfect keratinocyte HaCaT cells. Further mouse model studies show that PEI-Triton-6 can encapsulate and deliver growth arrest-specific protein 6 (Gas6) plasmid through transdermal administration. The transfected Gas6 prolongs the anagen status, inhibits the apoptosis of hair follicle cells, and further promotes the proliferation and differentiation of hair follicle cells. The PEI-Triton-6/pDNA_Gas6 complexes can obviously alleviate hair loss in androgenetic alopecia mice and provides a promising strategy for gene therapy via transdermal administration.

An Update on Photodynamic Therapy of Psoriasis—Current Strategies and Nanotechnology as a Future Perspective

Psoriasis (PS) is an immune-mediated skin disease with substantial negative effects on patient quality of life. Despite significant progress in the development of novel treatment options over the past few decades, a high percentage of patients with psoriasis remain undertreated and require new medications with superior long-term efficacy and safety. One of the most promising treatment options against psoriatic lesions is a form of phototherapy known as photodynamic therapy (PDT), which involves either the systemic or local application of a cell-targeting photosensitizing compound, followed by selective illumination of the lesion with visible light. However, the effectiveness of clinically incorporated photosensitizers in psoriasis treatment is limited, and adverse effects such as pain or burning sensations are frequently reported. In this study, we performed a literature review and attempted to provide a pooled estimate of the efficacy and short-term safety of targeted PDT in the treatment of psoriasis. Despite some encouraging results, PDT remains clinically underutilized. This highlights the need for further studies that will aim to evaluate the efficacy of a wider spectrum of photosensitizers and the potential of nanotechnology in psoriasis treatment.

Lyotropic liquid crystals for parenteral drug delivery

The necessity for long-term treatments of chronic diseases has encouraged the development of novel long-acting parenteral formulations intending to improve drug pharmacokinetics and therapeutic efficacy. Lately, one of the novel approaches has been developed based on lipid-based liquid crystals. The lyotropic liquid crystal (LLC) systems consist of amphiphilic molecules and are formed in presence of solvents with the most common types being cubic, hexagonal and lamellar mesophases. LC injectables have been recently developed based on polar lipids that spontaneously form liquid crystal nanoparticles in aqueous tissue environments to create the in-situ long-acting sustained-release depot to provide treatment efficacy over extended periods. In this manuscript, we have consolidated and summarized the various type of liquid crystals, recent formulation advancements, analytical evaluation, and therapeutic application of lyotropic liquid crystals in the field of parenteral sustained release drug delivery.

Novel Pharmaceutical Strategies for Enhancing Skin Penetration of Biomacromolecules

Skin delivery of biomacromolecules holds great advantages in the systemic and local treatment of multiple diseases. However, the densely packed stratum corneum and the tight junctions between keratinocytes stand as formidable skin barriers against the penetration of most drug molecules. The large molecular weight, high hydrophilicity, and lability nature of biomacromolecules pose further challenges to their skin penetration. Recently, novel penetration enhancers, nano vesicles, and microneedles have emerged as efficient strategies to deliver biomacromolecules deep into the skin to exert their therapeutic action. This paper reviews the potential application and mechanisms of novel skin delivery strategies with emphasis on the pharmaceutical formulations.

Solid lipid nanoparticles and nanostructured lipid carrier-based nanotherapeutics for the treatment of psoriasis

INTRODUCTION

Psoriasis is an auto-immune inflammatory skin disease affecting people worldwide. Its topical therapy via different nanoformulations prevents the long-term side-effects of conventional formulations. Nanocarriers, especially solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs), pose extra benefits in topical drug delivery due to their lipid constituents. Although both natural and synthetic anti-psoriatic drugs have been successfully incorporated in these nanoformulations, yet further studies including dual drug-loadings are being carried out for assessing their efficacy.

AREAS COVERED

This review aims at describing the different aspects of SLNs and NLCs in psoriasis, including their skin permeation behavior and the various drug molecules incorporated. The recent studies with single- and dual drug-loaded SLNs and NLCs have also been discussed in the review.

EXPERT OPINION

SLNs and NLCs have been very effective in mitigating psoriasis when compared to commercial formulations. They have also shown promising results when loaded with two drugs, thus overcoming drawbacks of traditional combination therapy. Therefore, various drug/antibody/siRNA combinations can be selected in the upcoming research works to evaluate their synergistic performance against psoriasis. However, the conclusions drawn so far are only based on the pre-clinical studies and hence further investigations are required to obtain their clinical trial outcomes.

TNFα siRNA delivery by nanoparticles and photochemical internalization for psoriasis topical therapy

Psoriasis is a chronic inflammatory skin disease that presents increased expression of tumor necrosis factor α (TNFα), a proinflammatory cytokine. The discovery of RNA interference (RNAi), mediated by short interfering RNA (siRNA), made it possible for the expression of some genes to be eliminated. However, for its application, it is necessary to use carriers that can protect siRNA and release it in the target cells. Herein, we developed a delivery system for siRNA based on hybrid polymer-lipid nanoparticles (PLNs) and combined this system with photochemical internalization (PCI), photoactivating the photosensitizer TPPS2a, to optimize the endosomal escape of TNFα siRNA in the cytoplasm, aiming to use the system as a topical formulation to treat psoriasis. The PLNs composed of 2.0% of Compritol® 888 ATO (lipid), 1.5% of poloxamer 188 and 0.1% of the cationic polymer poly(allylamine hydrochloride) showed an average nanoparticle size of 142 nm, a zeta potential of +25 mV, and the ability to efficiently coencapsulate TPPS2a and complexed siRNA. In addition, these materials did not present cellular toxicity and showed high cellular uptake. In vitro delivery studies using porcine skin model revealed that the PLNs delivered siRNA and TPPS2a into the skin. The efficacy was verified using an in vivo psoriasis animal (hairless mouse) model induced by imiquimod (IMQ) cream. The results revealed that PLN-TPPS2a-TNFα siRNA combined with PCI resulted in a decrease in the levels of TNFα, showing the efficiency of the treatment to silence this cytokine in psoriatic lesions, which was accompanied by a reduction in the redness and scaling of the mouse skin. The results showed the potential of the developed PLNs in combined silencing gene therapy and PCI for topical treatment of psoriasis.

Formulation-based approaches for dermal delivery of vaccines and therapeutic nucleic acids: Recent advances and future perspectives

A growing variety of biological macromolecules are in development for use as active ingredients in topical therapies and vaccines. Dermal delivery of biomacromolecules offers several advantages compared to other delivery methods, including improved targetability, reduced systemic toxicity, and decreased degradation of drugs. However, this route of delivery is hampered by the barrier function of the skin. Recently, a large body of research has been directed toward improving the delivery of macromolecules to the skin, ranging from nucleic acids (NAs) to antigens, using noninvasive means. In this review, we discuss the latest formulation-based efforts to deliver antigens and NAs for vaccination and treatment of skin diseases. We provide a perspective of their advantages, limitations, and potential for clinical translation. The delivery platforms discussed in this review may provide formulation scientists and clinicians with a better vision of the alternatives for dermal delivery of biomacromolecules, which may facilitate the development of new patient-friendly prophylactic and therapeutic medicines.

Preclinical study of methotrexate-based hydrogels versus surfactant based liquid crystal systems on psoriasis treatment

Psoriasis is an autoimmune, inflammatory and chronic skin disease in which cell growth and proliferation are increased, causing erythema, lesions and skin's peeling. Oral methotrexate (MTX) is the first-choice drug when phototherapy or retinoid treatment are not effective. Topical administration can be advantageous to better orientate the drug's delivery; however, the stratum corneum performs as a barrier for hydrofilic drugs penetration. This study sought to evaluate two different types of vehicles for MTX on the psoriasis treatment - hydrogel and liquid crystal systems (LCs). Lamellar and hexagonal liquid crystalline phases were selected from a ternary phase diagram based on polysorbate 80, isopropyl miristate and water. The hydrogel was based on alkylated carbomer (ACH). Rheological analysis showed ACH was more elastic than lamellar and hexagonal phases. ACH interacted better with pig skin than LCs in bioadhesion assay. Preclinical study revealed the ACH decreased inflammation in mice with induced psoriasis, being as effective as dexamethasone to regulate epidermis thickness, COX-2 and myeloperoxidase activity and TNF-α level, while LCs demonstrated inflammatory effect. Therefore, MTX-loaded hydrogel based platforms are indicated for local treatment of psoriasis and present great potential for further studies.

Nanotechnology-based Drug Delivery Systems as Potential for Skin Application: A Review

Administration of substances through the skin represents a promising alternative, in relation to other drug administration routes, due to its large body surface area, in order to offer ideal and multiple sites for drug administration. In addition, the administration of drugs through the skin avoids the first-pass metabolism, allowing an increase in the bioavailability of drugs, as well as reducing their side effects. However, the stratum corneum (SC) comprises the main barrier of protection against external agents, mainly due to its structure, composition and physicochemical properties, becoming the main limitation for the administration of substances through the skin. In view of the above, pharmaceutical technology has allowed the development of multiple drug delivery systems (DDS), which include liquid crystals (LC), cubosomes, liposomes, polymeric nanoparticles (PNP), nanoemulsions (NE), as well as cyclodextrins (CD) and dendrimers (DND). It appears that the DDS circumvents the problems of drug absorption through the SC layer of the skin, ensuring the release of the drug, as well as optimizing the therapeutic effect locally. This review aims to highlight the DDS that include LC, cubosomes, lipid systems, PNP, as well as CD and DND, to optimize topical skin therapies.

Chitosan Membranes Filled with Cyclosporine A as Possible Devices for Local Administration of Drugs in the Treatment of Breast Cancer

The aim of this work is the design, preparation and characterization of membranes based on cyclosporine A (CsA) and chitosan carboxylate (CC) to be used as an implantable subcutaneous medical device for a prolonged therapeutic effect in the treatment of breast cancer. The choice to use CsA is due to literature data that have demonstrated its possible antitumor activity on different types of neoplastic cells. To this end, CsA was bound to CC through an amidation reaction to obtain a prodrug to be dispersed in a chitosan-based polymeric membrane. The reaction intermediates and the final product were characterized by Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (¹H-NMR). Membranes were analyzed by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The data obtained showed the effective formation of the amide bond between CsA and CC and the complete dispersion of CsA inside the polymeric membrane. Furthermore, preliminary tests, conducted on MDA-MB-231, a type of breast cancer cell line, have shown a high reduction in the proliferation of cancer cells. These results indicate the possibility of using the obtained membranes as an interesting strategy for the release of cyclosporin-A in breast cancer patients.

Development of a Liquid Crystal Formulation that Can Penetrate the Stratum Corneum for Intradermal Delivery of Small Interfering RNA

Topical delivery of small interfering RNA (siRNA) can be an attractive method for the treatment of skin diseases and improving the quality of life of patients. However, it is difficult for siRNA to pass through the two major barriers of the skin: the stratum corneum (SC) and tight junctions. We have previously reported that atopic dermatitis of skin without the SC can be efficiently treated by the intradermal administration of trans-activator of transcription (Tat) peptide and AT1002 (tight junction opening peptide). However, novel drug delivery systems are needed for effective SC penetration. Therefore, in the present study, we aimed to develop a lyotropic liquid crystalline (LC) system containing Tat and AT1002 for effective siRNA penetration through the SC. An LC formulation was prepared using selachyl alcohol and purified water, and its skin penetration ability was evaluated. No fluorescence was observed in mouse skin treated with a siRNA solution, as there was no intradermal localization of siRNA from naked siRNA. However, intradermal delivery of siRNA was remarkable and extensive with the LC formulation containing both Tat and AT1002. Semiquantitative analysis by brightness measurement revealed that the LC formulation containing both Tat and AT1002 had significantly enhanced intact skin permeability than other formulations. These results show that the functional peptides in the LC formulation increased SC penetration and intradermal delivery in the healthy skin. Therefore, this novel LC system may be useful in the treatment of various skin diseases.

Tackling the various classes of nano-therapeutics employed in topical therapy of psoriasis

Psoriasis is a dermatological chronic skin condition with underlying autoimmune etiology. It deeply affects patients' quality of life. Therefore, it was an interesting target for researchers throughout the past years. Conventionally, the treatment options include anti-inflammatory agents, immune suppressants, biologic treatment, and phototherapy. Nanotechnology offers promising characteristics that allow for tailoring a drug carrier to achieve dermal targeting, improved efficacy and minimize undesirable effects. Being the safest route, the first line of treatment and a targeted approach, we solely discussed the use of the topical route, combined with advanced drug delivery systems for the management of psoriasis in this article. Advanced systems include polymeric, metallic, lipidic and hybrid nanocarriers incorporating different active agents. All formerly mentioned types of drug delivery systems were investigated through the past decades for the purpose of topical application on psoriatic plaques. Scientists' efforts are promising to reach an optimized formula with a convenient dosage form to improve efficacy, safety, and compliance for the treatment of psoriasis. Accordingly, it will offer a better quality of life for patients.

Small interfering RNA targeting of keratin 17 reduces inflammation in imiquimod-induced psoriasis-like dermatitis

Background

Psoriasis is a common chronic inflammatory skin disease with 2% to 3% prevalence worldwide and a heavy social-psychological burden for patients and their families. As the exact pathogenesis of psoriasis is still unknown, the current treatment is far from satisfactory. Thus, there is an urgent need to find a more effective therapy for this disease. Keratin 17 (K17), a type I intermediate filament, is overexpressed in the psoriatic epidermis and plays a critical pathogenic role by stimulating T cells in psoriasis. Therefore, we hypothesized that inhibiting K17 may be a potential therapeutic approach for psoriasis. This study aimed to investigate the therapeutic effect of K17-specific small interfering RNA (siRNA) on mice with imiquimod (IMQ)-induced psoriasis-like dermatitis.

Methods

Eight-week-old female BALB/c mice were administered a 5% IMQ cream on both ears to produce psoriatic dermatitis. On day 3, K17 siRNA was mixed with an emulsion matrix and applied topically to the left ears of the mice after IMQ application every day for 7 days. The right ears of the mice were treated in parallel with negative control (NC) siRNA. Inflammation was evaluated by gross ear thickness, histopathology, the infiltration of inflammatory cells (CD3⁺ T cells and neutrophils) using immunofluorescence, and the expression of cytokine production using real-time quantitative polymerase chain reaction. The obtained data were statistically evaluated by unpaired t-tests and a one-way analysis of variance.

Results

The severity of IMQ-induced dermatitis on K17 siRNA-treated mice ears was significantly lower than that on NC siRNA-treated mice ears, as evidenced by the alleviated ear inflammation phenotype, including decreased ear thickness, infiltration of inflammatory cells (CD3⁺ T cells and neutrophils), and inflammatory cytokine/chemokine expression levels (interleukin 17 [IL-17], IL-22, IL-23, C-X-C motif chemokine ligand 1, and C-C motif chemokine ligand 20) (P < 0.05 vs. the Blank or NC siRNA groups). Compared to the NC siRNA treatment, the K17 siRNA treatment resulted in increased K1 and K10 expression, which are characteristic of keratinocyte differentiation (vs. NC siRNA, K17 siRNA1 group: K1, t = 4.782, P = 0.0050; K10, t = 3.365, P = 0.0120; K17 siRNA2 group: K1, t = 4.104, P = 0.0093; K10, t = 4.168, P = 0.0042; siRNA Mix group: K1, t = 3.065, P = 0.0221; K10, t = 10.83, P < 0.0001), and decreased K16 expression, which is characteristic of keratinocyte proliferation (vs. NC siRNA, K17 siRNA1 group: t = 4.156, P = 0.0043; K17 siRNA2 group: t = 2.834, P = 0.0253; siRNA Mix group: t = 2.734, P = 0.0250).

Conclusions

Inhibition of K17 expression by its specific siRNA significantly alleviated inflammation in mice with IMQ-induced psoriasis-like dermatitis. Thus, gene therapy targeting K17 may be a potential treatment approach for psoriasis.

Non-invasive drug delivery technology: development and current status of transdermal drug delivery devices, techniques and biomedical applications

Pay-load deliveries across the skin barrier to the systemic circulation have been one of the most challenging delivery options. Necessitated requirements of the skin and facilitated skin layer cross-over delivery attempts have resulted in development of different non-invasive, non-oral methods, devices and systems which have been standardized, concurrently used and are in continuous upgrade and improvements. Iontophoresis, electroporation, sonophoresis, magnetophoresis, dermal patches, nanocarriers, needled and needle-less shots, and injectors are among some of the methods of transdermal delivery. The current review covers the current state of the art, merits and shortcomings of the systems, devices and transdermal delivery patches, including drugs' and other payloads' passage facilitation techniques, permeation and absorption feasibility studies, as well as physicochemical properties affecting the delivery through different transdermal modes along with examples of drugs, vaccines, genes and other payloads.

Liquid crystalline nanodispersion functionalized with cell-penetrating peptides improves skin penetration and anti-inflammatory effect of lipoic acid after in vivo skin exposure to UVB radiation

In this study, the development and the performance of a new targeted liquid crystalline nanodispersion (LCN) by the attachment of cell-penetrating peptides (CPP) onto their surfaces to improve skin delivery of lipoic acid (LA) were evaluated. For that, the synthesis and characterization of this new platform as well as its spatiotemporal analysis from in vitro and in vivo topical application were explored and extensively discussed in this paper. The TAT or D4 peptides were chosen as CPP due to specific target strategies by the charge grouping on the skin surface or target the overexpressed epidermal growth factor receptor (EGFR) of cell membrane of keratinocytes, respectively. Thus, the nanoparticle characterization results when taken together suggested that designed LCNs maintained their hexagonal phase structure, nanoscale particle size, and low polydispersity index even after drug, lipopolymers, and peptide additions, which are proved to be favorable for topical skin delivery. There were no statistical differences among the LCNs investigated, except for superficial charge of LCN conjugated with TAT which may have altered the LCN zeta potential due to cationic charge of TAT amino acid sequence compared with D4. The cumulative amounts of LA retained into the skin were determined to be even higher coming from the targeted LCNs. Moreover, the exogenous antioxidant application of the LA from the LCNs can prevent ROS damage, which was demonstrated by this study with the less myeloperoxidase (MPO) activity and decrease in cytokine levels (TNF-alpha and IL-1β) generated by the oxidative stress modulation. Together, the data presented highlights the potential of these targeted LCNs, and overall, opens new frontiers for preclinical trials.

Bioresponsive nanostructured systems for sustained naltrexone release and treatment of alcohol use disorder: Development and biological evaluation

In this study, microemulsions capable of transforming into nanostructured hexagonal phase gels in vivo upon uptake of biological fluids for naltrexone prolonged release were investigated as a strategy for management of alcohol use disorder (AUD). Microemulsions were prepared using monoolein, tricaprylin, water and propylene glycol; after preliminary characterization, one formulation was selected, which contained 55% of monoolein-tricaprylin (M-55). This microemulsion displayed size below 200 nm and Newtonian rheological behavior. Liquid crystalline gels formed in vitro upon 8 h of contact with water following a second order kinetics. After 120 h, <50% of naltrexone was released in vitro independently on drug loading (5 or 10%). In vivo, gels formed within 24 h of M-55 subcutaneous administration, and persisted locally for over 30 days providing slow release of the fluorescent marker Alexa fluor compared to a solution. Using the conditioned place preference paradigm, a test used to measure drug's rewarding effects, a single dose of M-55 containing 5% naltrexone reduced the time spent in the ethanol-paired compartment by 1.8-fold compared to saline; this effect was similar to that obtained with daily naltrexone injections, demonstrating the formulation efficacy and its ability to reduce dosing frequency. A more robust effect was observed following administration of M-55 containing 10% of naltrexone, which was compatible with aversion. These results support M-55 as a platform for sustained release of drugs that can be further explored for management of AUD to reduce dosing frequency and aid treatment adherence.

Fractional Laser-Mediated siRNA Delivery for Mitigating Psoriasis-like Lesions via IL-6 Silencing

The poor permeability of topically applied macromolecules such as small interfering RNA (siRNA) has inhibited the translation to clinical application. In this study, the fractional CO₂ laser-assisted approach was developed to describe siRNA permeation enhancement mediated by the created microchannels for silencing the gene to treat psoriasiform lesions. In vitro permeation using Franz cell and in vivo interleukin (IL)-6 silencing using psoriasis-like plaque in mice were evaluated to verify the impact of the laser irradiation. Low-fluence laser exposure enabled a significant increase in skin transport of siRNA, peptide, and 5-fluorouracil (5-FU). The laser treatment resulted in the enhancement of siRNA flux by 33- and 14-fold as compared to the control in nude mouse and pig skin, respectively. The laser exposure also promoted siRNA penetration across psoriatic and photoaging skins with the deficient barrier, although the enhancement level was minor compared to that of intact skin. The 3D images of confocal microscopy revealed a diffusion of macromolecules into the laser-created microchannels; the radial and vertical distribution to the surrounding and deep tissues followed this. A single laser treatment and the following topical siRNA administration were able to reduce IL-6 expression by 64% in the psoriatic skin model. Laser assistance led to the marked improvement in the plaque and the reduction of specific cytokine expression, keratinocyte proliferation, and neutrophil infiltration. Our data support the use of the fractional laser for delivery of functional nucleic acid into the skin and the target cells.

Nature-Inspired Design and Application of Lipidic Lyotropic Liquid Crystals

Amphiphilic lipids aggregate in aqueous solution into a variety of structural arrangements. Among the plethora of ordered structures that have been reported, many have also been observed in nature. In addition, due to their unique morphologies, the hydrophilic and hydrophobic domains, very high internal interfacial surface area, and the multitude of possible order-order transitions depending on environmental changes, very promising applications have been developed for these systems in recent years. These include crystallization in inverse bicontinuous cubic phases for membrane protein structure determination, generation of advanced materials, sustained release of bioactive molecules, and control of chemical reactions. The outstanding diverse functionalities of lyotropic liquid crystalline phases found in nature and industry are closely related to the topology, including how their nanoscopic domains are organized. This leads to notable examples of correlation between structure and macroscopic properties, which is itself central to the performance of materials in general. The physical origin of the formation of the known classes of lipidic lyotropic liquid crystalline phases, their structure, and their occurrence in nature are described, and their application in materials science and engineering, biology, medical, and pharmaceutical products, and food science and technology are exemplified.

Liquid crystalline nanoreservoir releasing a highly skin-penetrating berberine oleate complex for psoriasis management

Aim: The current work highlighted preparation of highly penetrating liquid crystalline nanoparticulates (LCNPs) reservoir of a solubility modified berberine oleate (Brb-OL) complex for effective psoriasis management. Materials & methods: Brb-OL-loaded LCNPs (Brb-OL-LCNPs) were prepared using hydrotrope method. Results: The proposed Brb-OL-LCNPs showed a particle size of 137 ± 3.7 nm and negative ζ-potential (-38 ± -5.85 mV). Brb-OL-LCNPs showed a threefold increase in the drug accumulated within rat skin and around tenfold increase in the drug permeation compared with crude Brb. In vivo studies revealed that topical application of Brb-OL-LCNPs hydrogel significantly alleviated psoriasis symptoms and reduced the levels of psoriatic inflammatory cytokines. Conclusion: Formulating Brb-OL in the LCNPs controlled the release, retention and permeation of the drug across skin layers, which are of prime importance for psoriasis management.

In Vitro TyRP-1 Knockdown Based on siRNA Carried by Liquid Crystalline Nanodispersions: an Alternative Approach for Topical Treatment of Vitiligo

PURPOSE

Vitiligo is a skin disease characterized by depigmentation and the presence of white patches that are associated with the loss of melanocytes. The most common explanation for the cause of this condition is that it is an autoimmune condition. TyRP-1 is involved in melanin pigment synthesis but can also function as a melanocyte differentiation antigen. This protein plays a role in the autoimmune destruction of melanocytes, which results in the depigmentation, characteristic of this disease. In this study, we evaluated liquid crystalline nanodispersions as non-viral vectors to deliver siRNA-TyRP-1 as an alternative for topical treatment of vitiligo.

METHODS

Liquid crystalline nanodispersions were obtained and characterized with respect to their physical-chemical parameters including size, PdI and zeta potential, as well as Small Angle X-ray Scattering and complexing to siRNA. The effects of the liquid crystalline nanodispersions on the cellular viability, cell uptake and levels of the knockdown target TyRP-1 were evaluated in melan-A cells after 24 h of treatment.

RESULTS

The liquid crystalline nanodispersions demonstrated adequate physical-chemical parameters including nanometer size and a PdI below 0.38. These systems promoted a high rate of cell uptake and an impressive TyRP-1 target knockdown (> 80%) associated with suitable loading of TyRp-1 siRNA.

CONCLUSIONS

We demonstrated that the liquid crystalline nanodispersions showed promising alternative for the topical treatment of vitiligo due to their physical parameters and ability in knockdown the target protein involved with autoimmune destruction of melanocytes.

Transdermal immunomodulation: Principles, advances and perspectives

Immunomodulation, manipulation of the immune responses towards an antigen, is a promising strategy to treat cancer, infectious diseases, allergies, and autoimmune diseases, among others. Unique features of the skin including the presence of tissue-resident immune cells, ease of access and connectivity to other organs makes it a unique target organ for immunomodulation. In this review, we summarize advances in transdermal delivery of agents for modulating the immune responses for vaccination as well as tolerization. The biological foundation of skin-based immunomodulation and challenges in its implementation are described. Technological approaches aimed at enhancing the delivery of immunomodulatory therapeutics into skin are also discussed in this review. Progress made in the treatment of several specific diseases including cancer, infections and allergy are discussed. Finally, this review discusses some practical considerations and offers some recommendations for future studies in the field of transdermal immunomodulation.

Towards topical microRNA-directed therapy for epidermal disorders

There remains an unmet dermatological need for innovative topical agents that achieve better longterm outcomes with fewer side effects. Modulation of the expression and activity of microRNA (miRNAs) represents an emerging translational framework for the development of such innovative therapies because changes in the expression of one miRNA can have wide-ranging effects on diverse cellular processes associated with disease. In this short review, the roles of miRNA in epidermal development, psoriasis, cutaneous squamous cell carcinoma and re-epithelisation are highlighted. Consideration is given to the delivery of oligonucleotides that mimic or inhibit miRNA function using vehicles such as cell penetrating peptides, spherical nucleic acids, deformable liposomes and liquid crystalline nanodispersions. Formulation of miRNA-directed oligonucleotides with such skin-penetrating epidermal agents will drive the development of RNA-based cutaneous therapeutics for deployment as primary or adjuvant therapies for epidermal disorders.

Advances in structural design of lipid-based nanoparticle carriers for delivery of macromolecular drugs, phytochemicals and anti-tumor agents

The present work highlights recent achievements in development of nanostructured dispersions and biocolloids for drug delivery applications. We emphasize the key role of biological small-angle X-ray scattering (BioSAXS) investigations for the nanomedicine design. A focus is given on controlled encapsulation of small molecular weight phytochemical drugs in lipid-based nanocarriers as well as on encapsulation of macromolecular siRNA, plasmid DNA, peptide and protein pharmaceuticals in nanostructured nanoparticles that may provide efficient intracellular delivery and triggered drug release. Selected examples of utilisation of the BioSAXS method for characterization of various types of liquid crystalline nanoorganizations (liposome, spongosome, cubosome, hexosome, and nanostructured lipid carriers) are discussed in view of the successful encapsulation and protection of phytochemicals and therapeutic biomolecules in the hydrophobic or the hydrophilic compartments of the nanocarriers. We conclude that the structural design of the nanoparticulate carriers is of crucial importance for the therapeutic outcome and the triggered drug release from biocolloids.

Effect of Liquid Crystalline Systems Containing Antimicrobial Compounds on Infectious Skin Bacteria

This study aimed (i) to prepare liquid crystalline systems (LCS) of glyceryl monooleate (GMO) and water containing antibacterial compounds and (ii) to evaluate their potential as drug delivery systems for topical treatment of bacterial infections. Therefore, LCS containing CPC (cetylpyridinium chloride) (LCS/CPC) and PHMB (poly(hexamethylene biguanide) hydrochloride) (LCS/PHMB) were prepared and the liquid crystalline phases were identified by polarizing light microscopy 24 h and 7 days after preparation. The in vitro drug release profile and in vitro antibacterial activity of the systems were assessed using the double layer agar diffusion method against Staphylococcus aureus, methicillin-resistant S. aureus, Staphylococcus epidermidis, Escherichia coli, and Enterococcus faecalis. The interaction between GMO and the drugs was evaluated by a drug absorption study. Stable liquid crystalline systems containing CPC and PHMB were obtained. LCS/PHMB decreased the PHMB release rate and exerted strong antibacterial activity against all the investigated bacteria. In contrast, CPC interacted with GMO so strongly that it became attached to the system; the amount released was not sufficient to exert antibacterial activity. Therefore, the studied liquid crystalline systems were suitable to deliver PHMB, but not CPC. Accordingly, it was demonstrated that GMO interacts with each drug differently, which may interfere in the final efficiency of GMO/water LCS.

In vitro psoriasis models with focus on reconstructed skin models as promising tools in psoriasis research

Psoriasis is a complex chronic immune-mediated inflammatory cutaneous disease associated with the development of inflammatory plaques on the skin. Studies proved that the disease results from a deregulated interplay between skin keratinocytes, immune cells and the environment leading to a persisting inflammatory process modulated by pro-inflammatory cytokines and activation of T cells. However, a major hindrance to study the pathogenesis of psoriasis more in depth and subsequent development of novel therapies is the lack of suitable pre-clinical models mimicking the complex phenotype of this skin disorder. Recent advances in and optimization of three-dimensional skin equivalent models have made them attractive and promising alternatives to the simplistic monolayer cultures, immunological different in vivo models and scarce ex vivo skin explants. Moreover, human skin equivalents are increasing in complexity level to match human biology as closely as possible. Here, we critically review the different types of three-dimensional skin models of psoriasis with relevance to their application potential and advantages over other models. This will guide researchers in choosing the most suitable psoriasis skin model for therapeutic drug testing (including gene therapy via siRNA molecules), or to examine biological features contributing to the pathology of psoriasis. However, the addition of T cells (as recently applied to a de-epidermized dermis-based psoriatic skin model) or other immune cells would make them even more attractive models and broaden their application potential. Eventually, the ultimate goal would be to substitute animal models by three-dimensional psoriatic skin models in the pre-clinical phases of anti-psoriasis candidate drugs. Impact statement The continuous development of novel in vitro models mimicking the psoriasis phenotype is important in the field of psoriasis research, as currently no model exists that completely matches the in vivo psoriasis skin or the disease pathology. This work provides a complete overview of the different available in vitro psoriasis models and suggests improvements for future models. Moreover, a focus was given to psoriatic skin equivalent models, as they offer several advantages over the other models, including commercial availability and validity. The potential and reported applicability of these models in psoriasis pre-clinical research is extensively discussed. As such, this work offers a guide to researchers in their choice of pre-clinical psoriasis model depending on their type of research question.

Local co-administration of gene-silencing RNA and drugs in cancer therapy: State-of-the art and therapeutic potential

Gene-silencing miRNA and siRNA are emerging as attractive therapeutics with potential to suppress any genes, which could be especially useful in combination cancer therapy to overcome multidrug resistant (MDR) cancer. Nanomedicine aims to advance cancer treatment through functional nanocarriers that delivers one or more therapeutics to cancer tissue and cells with minimal off-target effects and suitable release kinetics and dosages. Although much effort has gone into developing circulating nanocarriers with targeting functionality for systemic administration, another alternative and straightforward approach is to utilize formulations to be administered directly to the site of action, such as pulmonary and intratumoral delivery. The combination of gene-silencing RNA with drugs in nanocarriers for localized delivery is emerging with promising results. In this review, the current progress and strategies for local co-administration of RNA and drug for synergistic effects and future potential in cancer treatment are presented and discussed. Key advances in RNA-drug anticancer synergy and localized delivery systems were combined with a review of the available literature on local co-administration of RNA and drug for cancer treatment. It is concluded that advanced delivery systems for local administration of gene-silencing RNA and drug hold potential in treatment of cancer, depending on indication. In particular, there are promising developments using pulmonary delivery and intratumoral delivery in murine models, but further research should be conducted on other local administration strategies, designs that achieve effective intracellular delivery and maximize synergy and feasibility for clinical use.

Effects of nanoparticles with hydrotropic nicotinamide on tacrolimus: permeability through psoriatic skin and antipsoriatic and antiproliferative activities

The hybrid system based on nanoparticles (NPs) self-assembled by the conjugations of hyaluronic acid with cholesterol (HA–Chol NPs) combined with nicotinamide (NIC) for tacrolimus (FK506), ie, FK506 NPs–NIC, has been confirmed to exhibit a significant synergistic effect on FK506 permeation through and into intact skin; thus, it may be a promising approach for FK506 to effectively treat skin diseases. The aim of this study was to evaluate its potential for the treatment of psoriasis. In vitro permeation through the psoriatic skin was carried out, and the results revealed that the combination of NPs with NIC exhibited a significant synergistic effect on FK506 deposition within the psoriatic skin (3.40±0.67 μg/cm²) and penetration through the psoriatic skin (30.86±9.66 μg/cm²). The antipsoriatic activity of FK506 NPs–NIC was evaluated through the treatment for imiquimod (IMQ)-induced psoriasis. The psoriasis area and severity index (PASI) score demonstrated that FK506 HA–Chol NPs–NIC exerted the effect on ameliorating the skin lesions comparable to clobetasol propionate (a positive drug for psoriasis) and superior to commercial FK506 ointment (Protopic^®), and the histological study showed that it presented a synergistic effect on antipsoriasis after FK506 incorporation into NPs combined with NIC hydrotropic system, which might ultimately increase the therapeutic effect and minimize the systemic side effects by reducing the overall dose of FK506. RAW 264.7 cell uptake presented the enhancement of drugs delivered into cells by HA–Chol NPs–NIC. The antiproliferative activity on HaCaT cells identified that FK506 HA–Chol NPs–NIC exhibited significant inhibiting effects on HaCaT proliferation. The results support that the combination of HA–Chol NPs with NIC is a promising approach for FK506 for the treatment of psoriasis.

Nanoparticle-Enabled Transdermal Drug Delivery Systems for Enhanced Dose Control and Tissue Targeting

Transdermal drug delivery systems have been around for decades, and current technologies (e.g., patches, ointments, and creams) enhance the skin permeation of low molecular weight, lipophilic drugs that are efficacious at low doses. The objective of current transdermal drug delivery research is to discover ways to enhance skin penetration of larger, hydrophilic drugs and macromolecules for disease treatment and vaccination. Nanocarriers made of lipids, metals, or polymers have been successfully used to increase penetration of drugs or vaccines, control drug release, and target drugs to specific areas of skin in vivo. While more research is needed to identify the safety of nanocarriers, this technology has the potential to expand the use of transdermal routes of administration to a wide array of therapeutics. Here, we review the current state of nanoparticle skin delivery systems with special emphasis on targeting skin diseases.