An elastic liposomal formulation for RNAi-based topical treatment of skin disorders: Proof-of-concept in the treatment of psoriasis

Topical gene editing therapeutics using lipid nanoparticles: 'gene creams' for genetic skin diseases?

Patients living with inherited skin diseases have benefited from recent advances in DNA sequencing technologies that provide new or improved diagnostics. However, developing and delivering new treatments for the 'genodermatoses' remains challenging. The goal of creating topical preparations that can recover the inherent gene pathology remains largely aspirational. However, recent progress in two fields - the chemistry of topical delivery formulations (lipid nanoparticles) and the molecular biology of gene repair (CRISPR-Cas9, base and prime editing) - presents new opportunities to address this unmet need. In this review, we discuss how lipid nanoparticle delivery vehicles could be used to deliver gene-editing tools to formulate topical 'gene creams' suitable for the treatment of genodermatoses. We summarize the historical landscape of topical therapeutics and advances in gene editing that may herald an era of new therapies for patients with inherited skin disorders.

Splicing Modulation via Antisense Oligonucleotides in Recessive Dystrophic Epidermolysis Bullosa

Antisense oligonucleotides (ASOs) represent an emerging therapeutic platform for targeting genetic diseases by influencing various aspects of (pre-)mRNA biology, such as splicing, stability, and translation. In this study, we investigated the potential of modulating the splicing pattern in recessive dystrophic epidermolysis bullosa (RDEB) patient cells carrying a frequent genomic variant (c.425A > G) that disrupts splicing in the COL7A1 gene by using short 2'-O-(2-Methoxyethyl) oligoribo-nucleotides (2'-MOE ASOs). COL7A1-encoded type VII collagen (C7) forms the anchoring fibrils within the skin that are essential for the attachment of the epidermis to the underlying dermis. As such, gene variants of COL7A1 leading to functionally impaired or absent C7 manifest in the form of extensive blistering and wounding. The severity of the disease pattern warrants the development of novel therapies for patients. The c.425A > G variant at the COL7A1 exon 3/intron 3 junction lowers the efficiency of splicing at this junction, resulting in non-functional C7 transcripts. However, we found that correct splicing still occurs, albeit at a very low level, highlighting an opportunity for intervention by modulating the splicing reaction. We therefore screened 2'-MOE ASOs that bind along the COL7A1 target region ranging from exon 3 to the intron 3/exon 4 junction for their ability to modulate splicing. We identified ASOs capable of increasing the relative levels of correctly spliced COL7A1 transcripts by RT-PCR, sqRT-PCR, and ddPCR. Furthermore, RDEB-derived skin equivalents treated with one of the most promising ASOs exhibited an increase in full-length C7 expression and its accurate deposition along the basement membrane zone (BMZ).

The role of microRNA in psoriasis: A review

Psoriasis is a chronic immune-mediated inflammatory skin disease that involves a complex interplay between infiltrated immune cells and keratinocytes. Great progress has been made in the research on the molecular mechanism of coding and non-coding genes, which has helped in clinical treatment. However, our understanding of this complex disease is far from clear. MicroRNAs (miRNAs) are small non-coding RNA molecules that are involved in post-transcriptional regulation, characterised by their role in mediating gene silencing. Recent studies on miRNAs have revealed their important role in the pathogenesis of psoriasis. We reviewed the current advances in the study of miRNAs in psoriasis; the existing research has found that dysregulated miRNAs in psoriasis notably affect keratinocyte proliferation and/or differentiation processes, as well as inflammation progress. In addition, miRNAs also influence the function of immune cells in psoriasis, including CD4+ T cells, dendritic cells, Langerhans cells and so on. In addition, we discuss possible miRNA-based therapy for psoriasis, such as the topical delivery of exogenous miRNAs, miRNA antagonists and miRNA mimics. Our review highlights the potential role of miRNAs in the pathogenesis of psoriasis, and we expect more research progress with miRNAs in the future, which will help us understand this complex skin disease more accurately.

Advances in transdermal siRNAs delivery: A review of current research progress

Small interfering RNA (siRNAs) is a double-stranded RNA molecule which can hybridize with a specific mRNA sequence and block the translation of numerous genes to regulate endogenous genes and to defend the genome from invasive nucleic acids. The use of siRNAs has been studied as a treatment option for various skin conditions. One of the main obstacles in the dermal or transdermal delivery of this compound is low skin permeability, and application is limited by its negative charge, high polarity, susceptibility to degradation by nucleases, and difficulty in penetrating the skin barrier. Effective delivery of therapeutic biomolecules to their target is a challenging issue, which can be solved by innovations in drug delivery systems and lead to improvement of the efficiency of many new biopharmaceuticals. Designing of novel transdermal delivery systems garnered tremendous attention in both cosmeceutical and pharmaceutical research and industries, which offers a number of advantages. Developing safe and efficient siRNAs delivery vectors is essential for effective treatment of skin diseases. In recent years, significant progress has been made in the creation of delivery systems using lipids, polymers, cell-penetrating peptides, nanoparticles and other biologically active agents. In this review we will focus on the recent advancements in transdermal siRNAs delivery vectors, such as liposomes, dendrimers, cell-penetrating peptides, and spherical nucleic acid nanoparticles.

Nanoscale Topical Pharmacotherapy in Management of Psoriasis: Contemporary Research and Scope

Psoriasis is a typical dermal condition that has been anticipated since prehistoric times when it was mistakenly implicit in being a variant of leprosy. It is an atypical organ-specific autoimmune disorder, which is triggered by the activation of T-cells and/or B-cells. Until now, the pathophysiology of this disease is not completely explicated and still, many research investigations are ongoing. Different approaches have been investigated to treat this dreadful skin disease using various anti-psoriatic drugs of different modes of action through smart drug-delivery systems. Nevertheless, there is no ideal therapy for a complete cure of psoriasis owing to the dearth of an ideal drug-delivery system for anti-psoriatic drugs. The conventional pharmacotherapy approaches for the treatment of psoriasis demand various classes of anti-psoriatic drugs with optimum benefit/risk ratio and insignificant untoward effects. The advancement in nanoscale drug delivery had a great impact on the establishment of a nanomedicine-based therapy for better management of psoriasis in recent times. Nanodrug carriers are exploited to design and develop nanomedicine-based therapy for psoriasis. It has a promising future in the improvement of the therapeutic efficacy of conventional anti-psoriatic drugs. The present manuscript aims to discuss the pathophysiology, conventional pharmacotherapy, and contemporary research in the area of nanoscale topical drug delivery systems for better management of psoriasis including the significance of targeted pharmacotherapy in psoriasis.

Nanoparticles for Topical Application in the Treatment of Skin Dysfunctions-An Overview of Dermo-Cosmetic and Dermatological Products

Nanomaterials (NM) arouse interest in various fields of science and industry due to their composition-tunable properties and the ease of modification. They appear currently as components of many consumer products such as sunscreen, dressings, sports clothes, surface-cleaning agents, computer devices, paints, as well as pharmaceutical and cosmetics formulations. The use of NPs in products for topical applications improves the permeation/penetration of the bioactive compounds into deeper layers of the skin, providing a depot effect with sustained drug release and specific cellular and subcellular targeting. Nanocarriers provide advances in dermatology and systemic treatments. Examples are a non-invasive method of vaccination, advanced diagnostic techniques, and transdermal drug delivery. The mechanism of action of NPs, efficiency of skin penetration, and potential threat to human health are still open and not fully explained. This review gives a brief outline of the latest nanotechnology achievements in products used in topical applications to prevent and treat skin diseases. We highlighted aspects such as the penetration of NPs through the skin (influence of physical-chemical properties of NPs, the experimental models for skin penetration, methods applied to improve the penetration of NPs through the skin, and methods applied to investigate the skin penetration by NPs). The review summarizes various therapies using NPs to diagnose and treat skin diseases (melanoma, acne, alopecia, vitiligo, psoriasis) and anti-aging and UV-protectant nano-cosmetics.

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.

An Innovative Approach In Nanotechnology-Based Delivery System For The Effective Management Of Psoriasis

INTRODUCTION

Psoriasis is an ineradicable, non-contagious inflammatory autoimmune skin disorder exhibiting abnormal redness of the skin and flaky patches which affect the exposed body surface. It is caused by negative signals produced by the immune system, leading to excessive growth and differentiation of keratinocytes and other inflammatory reactions on the skin. The topical route is primarily preferred in treating skin disorders due to the smaller size of the drug molecule, which allows them to cross the outer layer of the skin, i.e., stratum corneum, and permeate into the deep layer, unlike transdermal and other routes. The conventional topical treatments used in the past, such as coal tar, and dithranol leads to meager patient compliance due to decreased potency, and imperfect aesthetic. In contrast, systemic therapy such as methotrexate, cyclosporine, and acitretin produce related side effects. At present, various novel carriers like liposomes, ethosomes, niosomes, nanostructured lipid carriers, etc., have shown promising results to treat psoriasis. Therefore, this review primarily concentrates on the current advancements in novel carriers for various drugs to treat psoriasis topically. Area covered: The objective of this review describes the detailed study such as pathophysiology, epidemiology, types, causes, diagnosis, and topical treatment options for psoriasis, as well as the role of the nanotechnology-based delivery system to manage psoriasis.

Lipid Nanoparticulate Drug Delivery Systems: Recent Advances in the Treatment of Skin Disorders

The multifunctional role of the human skin is well known. It acts as a sensory and immune organ that protects the human body from harmful environmental impacts such as chemical, mechanical, and physical threats, reduces UV radiation effects, prevents moisture loss, and helps thermoregulation. In this regard, skin disorders related to skin integrity require adequate treatment. Lipid nanoparticles (LN) are recognized as promising drug delivery systems (DDS) in treating skin disorders. Solid lipid nanoparticles (SLN) together with nanostructured lipid carriers (NLC) exhibit excellent tolerability as these are produced from physiological and biodegradable lipids. Moreover, LN applied to the skin can improve stability, drug targeting, occlusion, penetration enhancement, and increased skin hydration compared with other drug nanocarriers. Furthermore, the features of LN can be enhanced by inclusion in suitable bases such as creams, ointments, gels (i.e., hydrogel, emulgel, bigel), lotions, etc. This review focuses on recent developments in lipid nanoparticle systems and their application to treating skin diseases. We point out and consider the reasons for their creation, pay attention to their advantages and disadvantages, list the main production techniques for obtaining them, and examine the place assigned to them in solving the problems caused by skin disorders.

Novel archetype in psoriasis management bridging molecular dynamics in exploring novel therapies

Psoriasis is an autoimmune chronic inflammatory condition of skin affecting 125 million populaces around the globe. It is implicated as a result of multifaceted phenomena involving various cell and subcell activities with the aid of numerous cellular and molecular components including signaling aisle and regulatory proteins owing to the development of such hyperproliferative dermatological conditions. This involves a deeply complex and conflicting pathology owing to genetic and immunological deviations resulting from the unusual presentation of different signaling pathways and regulatory proteins. Explorations of these biomarkers and intervention of molecular and cellular processes in psoriasis are yet to be investigated and could be an exceptional aspect for understanding pathology with successful targeting of disease. In the presented study, we have integrated molecular insights, including signaling molecules, pathways, and proteins implicated in pathogenesis, and we have attempted to link this knowledge to the targeting of these phenomena in order to manage the conditions precisely. Further, therapeutic delivery approaches for targeting distinct layers of skin have also been investigated based on the application of different nanocarriers for successful psoriasis treatment.

Personalized Development of Antisense Oligonucleotides for Exon Skipping Restores Type XVII Collagen Expression in Junctional Epidermolysis Bullosa

Intermediate junctional epidermolysis bullosa caused by mutations in the COL17A1 gene is characterized by the frequent development of blisters and erosions on the skin and mucous membranes. The rarity of the disease and the heterogeneity of the underlying mutations renders therapy developments challenging. However, the high number of short in-frame exons facilitates the use of antisense oligonucleotides (AON) to restore collagen 17 (C17) expression by inducing exon skipping. In a personalized approach, we designed and tested three AONs in combination with a cationic liposomal carrier for their ability to induce skipping of COL17A1 exon 7 in 2D culture and in 3D skin equivalents. We show that AON-induced exon skipping excludes the targeted exon from pre-mRNA processing, which restores the reading frame, leading to the expression of a slightly truncated protein. Furthermore, the expression and correct deposition of C17 at the dermal-epidermal junction indicates its functionality. Thus, we assume AON-mediated exon skipping to be a promising tool for the treatment of junctional epidermolysis bullosa, particularly applicable in a personalized manner for rare genotypes.

Recent Advances in Nanomaterials for Dermal and Transdermal Applications

The stratum corneum, the most superficial layer of the skin, protects the body against environmental hazards and presents a highly selective barrier for the passage of drugs and cosmetic products deeper into the skin and across the skin. Nanomaterials can effectively increase the permeation of active molecules across the stratum corneum and enable their penetration into deeper skin layers, often by interacting with the skin and creating the distinct sites with elevated local concentration, acting as reservoirs. The flux of the molecules from these reservoirs can be either limited to the underlying skin layers (for topical drug and cosmeceutical delivery) or extended across all the sublayers of the epidermis to the blood vessels of the dermis (for transdermal delivery). The type of the nanocarrier and the physicochemical nature of the active substance are among the factors that determine the final skin permeation pattern and the stability of the penetrant in the cutaneous environment. The most widely employed types of nanomaterials for dermal and transdermal applications include solid lipid nanoparticles, nanovesicular carriers, microemulsions, nanoemulsions, and polymeric nanoparticles. The recent advances in the area of nanomaterial-assisted dermal and transdermal delivery are highlighted in this review.

MicroRNAs in Several Cutaneous Autoimmune Diseases: Psoriasis, Cutaneous Lupus Erythematosus and Atopic Dermatitis

MicroRNAs (miRNAs) are endogenous small non-coding RNA molecules that regulate the gene expression at a post-transcriptional level and participate in maintaining the correct cell homeostasis and functioning. Different specific profiles have been identified in lesional skin from autoimmune cutaneous diseases, and their deregulation cause aberrant control of biological pathways, contributing to pathogenic conditions. Detailed knowledge of microRNA-affected pathways is of crucial importance for understating their role in skin autoimmune diseases. They may be promising therapeutic targets with novel clinical implications. They are not only present in skin tissue, but they have also been found in other biological fluids, such as serum, plasma and urine from patients, and therefore, they are potential biomarkers for the diagnosis, prognosis and response to treatment. In this review, we discuss the current understanding of the role of described miRNAs in several cutaneous autoimmune diseases: psoriasis (Ps, 33 miRNAs), cutaneous lupus erythematosus (CLE, 2 miRNAs) and atopic dermatitis (AD, 8 miRNAs). We highlight their role as crucial elements implicated in disease pathogenesis and their applicability as biomarkers and as a novel therapeutic approach in the management of skin inflammatory 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.

Importance of microRNAs in Skin Oncogenesis and Their Suitability as Agents and Targets for Topical Therapy

Skin cancer is the most common cancer worldwide, with rapidly increasing incidence and consistent mortality. Skin cancer encompasses melanoma and non-melanoma skin cancer, which in turn is mainly divided into cutaneous squamous cell carcinoma and basal cell carcinoma. Small noncoding micro-RNAs (miRNAs) regulate protein expression after transcription and play a role in the development and progression of skin cancer. Deregulated expression of miRNAs in skin cancer is associated with cell proliferation, angiogenesis, metastasis, apoptosis, immune response, and drug resistance. Specific patterns of miRNAs in specific skin cancer types can be used as diagnostic markers. For therapeutic purposes, both miRNA and chemically modified variants thereof as well as miRNA antagonists (antagomiRs) or RNA inhibitors may be applied topically. Due to their specific physicochemical properties, physical or chemical diffusion promoters are used with varying degrees of success. There is no question by now that such preparations have a high potential for the treatment of epithelial skin tumors in particular.

Emerging Trends in Topical Delivery of Curcumin Through Lipid Nanocarriers: Effectiveness in Skin Disorders

Curcumin is a unique molecule naturally obtained from rhizomes of Curcuma longa. Curcumin has been reported to act on diverse molecular targets like receptors, enzymes, and co-factors; regulate different cellular signaling pathways; and modulate gene expression. It suppresses expression of main inflammatory mediators like interleukins, tumor necrosis factor, and nuclear factor κB which are involved in the regulation of genes causing inflammation in most skin disorders. The topical delivery of curcumin seems to be more advantageous in providing a localized effect in skin diseases. However, its low aqueous solubility, poor skin permeation, and degradation hinder its application for commercial use despite its enormous potential. Lipid-based nanocarrier systems including liposomes, niosomes, solid lipid nanoparticles, nanostructured lipid carriers, lyotropic liquid crystal nanoparticles, lipospheres, and lipid nanocapsules have found potential as carriers to overcome the issues associated with conventional topical dosage forms. Nano-size, lipophilic nature, viscoelastic properties, and occlusive effect of lipid nanocarriers provide high drug loading, hydration of skin, stability, enhanced permeation through the stratum corneum, and slow release of curcumin in the targeted skin layers. This review particularly focuses on the application of lipid nanocarriers for the topical delivery of curcumin in the treatment of various skin diseases. Furthermore, preclinical studies and patents have also indicated the emerging commercialization potential of curcumin-loaded lipid nanocarriers for effective drug delivery in skin disorders. Graphical Abstract.

Insightful exploring of microRNAs in psoriasis and its targeted topical delivery

Psoriasis is a common immune-mediated inflammatory skin disease. It includes multifaceted interaction between the immune system and the keratinocytes. Recent studies depicted the role of microRNAs (miRNAs) in hyperproliferation of keratinocytes and inflammatory cytokine production, which serve as biomarkers for diagnosis, monitoring treatment response, and prognosis. miRNAs are small nucleotide sequenced noncoding RNAs. Deregulation of miRNAs was found to be the most common factor in the studies pertaining to psoriasis. Hence, miRNA-based targeting for psoriasis treatment became the primary field of current research. miRNA due to its spatial and chemical properties offer different challenges in the process of its delivery. The topical delivery of different siRNAs and genes has paved a way to similar delivery of miRNA. The topical delivery of miRNAs to the skin can bring a revolutionary change in the field of psoriasis treatment.

Evolution of Nanotechnology in Delivering Drugs to Eyes, Skin and Wounds via Topical Route

The topical route is the most preferred one for administering drugs to eyes, skin and wounds for reaching enhanced efficacy and to improve patient compliance. Topical administration of drugs via conventional dosage forms such as solutions, creams and so forth to the eyes is associated with very low bioavailability (less than 5%) and hence, we cannot rely on these for delivering drugs to eyes more efficiently. An intravitreal injection is another popular drug delivery regime but is associated with complications like intravitreal hemorrhage, retinal detachment, endophthalmitis, and cataracts. The skin has a complex structure that serves as numerous physiological barriers to the entry of exogenous substances. Drug localization is an important aspect of some dermal diseases and requires directed delivery of the active substance to the diseased cells, which is challenging with current approaches. Existing therapies used for wound healing are costly, and they involve long-lasting treatments with 70% chance of recurrence of ulcers. Nanotechnology is a novel and highly potential technology for designing formulations that would improve the efficiency of delivering drugs via the topical route. This review involves a discussion about how nanotechnology-driven drug delivery systems have evolved, and their potential in overcoming the natural barriers for delivering drugs to eyes, skin and wounds.

Treatment of Psoriasis: A Comprehensive Review of Entire Therapies

Background:

Psoriasis is an autoimmune disease that ingeminates itself with the repeated proliferation of keratinocytes. It globally strikes a 2-5 % population on an average. Management of psoriasis remains a daunting task with various challenges influencing treatment, such as patient conformity and adherence to therapy, delicate patient profiles, psychological aspects, and skin as a barrier to topical delivery. The first part reviewed pathophysiology, triggering factors, and clinical classification. The second part reviewed all the therapies, such as topical, oral, biological, parenteral therapy, phototherapy, and the phyto-pharmaceuticals.

Methods:

The research data related to the existing and upcoming therapies for psoriasis treatment, several nanocarriers, existing marketed formulations, and detailed description of phytopharmaceuticals with their mechanism.

Results:

Topical therapy is the mainstay treatment option with limited adverse effects. Biological therapy has reformed conventional psoriasis treatment by being more efficacious and has increased patient acceptance due to decreased adverse events. Nanoformulations present an edge over conventional therapy due to improved anti-psoriatic effect and decreased side effects. Phyto-pharmaceuticals act as a complementary and alternative therapy for diminishing psoriasis symptoms.

Conclusion:

A rationalized cost-effective patient compliant therapy is required for effective management and complete cure of psoriasis.

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.

DOC-LS, a new liposome for dermal delivery, and its endocytosis by HaCaT and CCC-ESF-1 cells

The main objective of this work was to investigate the uptake channels of skin cells through which coumarin 6, transported by deoxycholate-mediated liposomes (DOC-LS), was internalised; this was also compared against the action of conventional LS. Coumarin 6-loaded DOC-LS and LS were characterised for size distribution, zeta potential, and shape, and analysed in vitro in human epidermal immortal keratinocyte (HaCaT) (epidermal) and human embryonic skin fibroblast (CCC-ESF-1) (dermal) cell lines. Various endocytosis inhibitors were incubated with cells treated with the nanocarriers. Flow cytometry results indicated that HaCaT and CCC-ESF-1 cells internalise the tested preparations through pinocytotic vesicles, macropinocytosis, clathrin-mediated endocytic pathways, and via lysosomes, which consume a considerable amount of energy. The endocytosis pathways of DOC-LS and LS showed no difference. This study provides a basis for the application of LS being combined with a microneedle system for efficient intracellular drug delivery, targeting cutaneous histocyte disorders.

Deduction of Novel Genes Potentially Involved in Keratinocytes of Type 2 Diabetes Using Next-Generation Sequencing and Bioinformatics Approaches

Keratinocytes constitute the major cell type of epidermis, which participates in re-epithelialization during wound repair and the immune defense response to pathogens. The aim of the current study was to explore the differentially expressed genes and novel microRNA (miRNA) regulations that are potentially involved in diabetic keratinocytes through next-generation sequencing (NGS) and bioinformatics approaches. A total of 420 differentially expressed genes between normal and diabetic keratinocytes were identified, and systematic bioinformatics analyses indicated that these differentially expressed genes were functionally enriched in interferon-alpha signaling, viral defense response, and immune response. Additionally, the potential miR-340-3p-DTX3L interaction that has been systematically validated in miRNA prediction databases was proposed to participate in the disrupted skin homeostasis, altering the defense and immune response of diabetic skin. The findings may provide new insights into understanding the pathogenesis of epidermal pathologies in diabetic patients and targeting novel molecules to advance diabetic skin care in clinical practice.

An ex vivo RNA trans-splicing strategy to correct human generalized severe epidermolysis bullosa simplex

Background

Generalized severe epidermolysis bullosa simplex (EBS‐gen sev) is a genetic blistering skin disease in which autosomal dominant mutations in either the keratin KRT5 or KRT14 genes lead to impaired function of the intermediate filament cytoskeleton in the basal epidermis. Here we present an ex vivo RNA trans‐splicing‐based therapeutic approach to correct the phenotype.

Objectives

To correct a mutation within exon 1 of the KRT14 gene, using a 5′‐trans‐splicing approach, where any mutation within the first seven exons could be replaced by a single therapeutic molecule.

Methods

A therapeutic RNA trans‐splicing molecule containing wild‐type exons 1–7 was stably transduced into an EBS patient‐derived keratinocyte line. Trans‐splicing was confirmed via reverse‐transcriptase polymerase chain reaction, Western blotting and immunofluorescence microscopy. Skin equivalents generated from corrected keratinocytes were grafted onto nude mice and analysed about 8 weeks post‐transplantation for regular epidermal stratification, trans‐splicing‐induced green fluorescent protein expression and blistering.

Results

Transplanted skin equivalents generated from trans‐splicing‐corrected patient keratinocytes showed a stable and blister‐free epidermis. KRT14 correction disrupted EBS‐gen sev‐associated proinflammatory signalling, as shown at the mRNA and protein levels. Disruption of the pathogenic feedback loop in addition to overall downregulation of KRT14 expression highlighted the effect of KRT14 correction on the EBS pathomechanism.

Conclusions

Our data demonstrate that trans‐splicing‐mediated mRNA therapy is an effective method for the correction of dominantly inherited KRT14 mutations at the transcriptional level. This results in the rescue of the EBS‐gen sev phenotype and stabilization of the epidermis in a xenograft mouse model.

What's already known about this topic?

RTM163, described in this study, was previously used in a transient in vitro transfection system, where the ability to correct KRT14 at the mRNA level was demonstrated.

What does this study add?

In this study, we stably transduced RTM163 in a second patient‐derived keratinocyte line.

Successful trans‐splicing was confirmed in this cell line.

The expression of disease‐related marker genes, which are characteristically deregulated in epidermolysis bullosa simplex, were analysed.

For the first time this study showed that RNA trans‐splicing molecule‐transduced patient keratinocytes can differentiate into a phenotypically normal and blister‐free epidermis in a xenograft mouse model.

What is the translational message?

This study shows the feasibility of using spliceosome‐mediated RNA trans‐splicing to generate a stable and blister‐free epidermis in vivo.

Combined with pre‐existing ex vivo gene therapeutic methods, this might be a valid option for future treatments of dominantly inherited genodermatoses.

Linked Comment: Bremer and van den Akker. Br J Dermatol 2019; 180:17–19.

Understanding the prospective of nano-formulations towards the treatment of psoriasis

Psoriasis is a consistently recurring, inflammatory, autoimmune disorder of the skin, affecting about 2-5% of the world population. Abundant therapeutic agents are accessible for the treatment of psoriasis. Nevertheless, none of them are entirely secure and effective to treat the disease without compromising patient compliance. Furthermore, already existing drugs are supposed to restrain the ailment and alleviate the sign and symptoms with no complete cure. However, they focus on restraining the disease and alleviating the symptoms without providing an absolute cure. Therefore there remains a vital challenge, to explore a new drug moiety or delivery system which could safely and effectively manage psoriasis without compromising patient compliance. Furthermore, conventional formulations offer reduced benefit/risk ratio of anti-psoriatic drugs, which limits the use of existing conventional formulations. Novel formulations based on nanocarriers are a promising prospect to overcome the limitation of conventional formulations by offering a reduction in dose, dosing frequency, dose-dependent, side effects with enhanced efficacy. Presently nano-formulations have gained widespread application for effective and safe treatment of psoriasis. The present review primarily focuses on conventional therapeutic strategy and recent advances in lipid-based, polymer-based and metallic nano-formulations of a variety of anti-psoriatic drugs. The practicability of various nanocarrier systems including liposomes, nanostructured lipid carriers, ethosomes, solid lipid nanoparticles, nanocapsules, micelles, dendrimers, gold nanoparticles and silver nanoparticles have been discussed in detail. The review also traces related patents to exemplify the role of various nanoparticles in psoriasis treatment. In a nutshell, nano-formulations remain established as a promising modality for treating psoriasis treatment as they propose better penetration, targeted delivery, enhanced safety, and efficacy.

Current and future technological advances in transdermal gene delivery

Transdermal gene delivery holds significant advantages as it is able to minimize the problems of systemic administration such as enzymatic degradation, systemic toxicity, and poor delivery to target tissues. This technology has the potential to transform the treatment and prevention of a range of diseases. However, the skin poses a great barrier for gene delivery because of the "bricks-and-mortar" structure of the stratum corneum and the tight junctions between keratinocytes in the epidermis. This review systematically summarizes the typical physical and chemical approaches to overcome these barriers and facilitate gene delivery via skin for applications in vaccination, wound healing, skin cancers and skin diseases. Next, the advantages and disadvantages of different approaches are discussed and the insights for future development are provided.

Breaking the Barrier - Potent Anti-Inflammatory Activity following Efficient Topical Delivery of Etanercept using Thermoresponsive Nanogels

Topical administration permits targeted, sustained delivery of therapeutics to human skin. Delivery to the skin, however, is typically limited to lipophilic molecules with molecular weight of < 500 Da, capable of crossing the stratum corneum. Nevertheless, there are indications protein delivery may be possible in barrier deficient skin, a condition found in several inflammatory skin diseases such as psoriasis, using novel nanocarrier systems.

Methods: Water in water thermo-nanoprecipitation; dynamic light scattering; zeta potential measurement; nanoparticle tracking analysis; atomic force microscopy; cryogenic transmission electron microscopy; UV absorption; centrifugal separation membranes; bicinchoninic acid assay; circular dichroism; TNFα binding ELISA; inflammatory skin equivalent construction; human skin biopsies; immunohistochemistry; fluorescence microscopy; western blot; monocyte derived Langerhans cells; ELISA

Results: Here, we report the novel synthesis of thermoresponsive nanogels (tNG) and the stable encapsulation of the anti-TNFα fusion protein etanercept (ETR) (~150 kDa) without alteration to its structure, as well as temperature triggered release from the tNGs. Novel tNG synthesis without the use of organic solvents was conducted, permitting in situ encapsulation of protein during assembly, something that holds great promise for easy manufacture and storage. Topical application of ETR loaded tNGs to inflammatory skin equivalents or tape striped human skin resulted in efficient ETR delivery throughout the SC and into the viable epidermis that correlated with clear anti-inflammatory effects. Notably, effective ETR delivery depended on temperature triggered release following topical application.

Conclusion: Together these results indicate tNGs hold promise as a biocompatible and easy to manufacture vehicle for stable protein encapsulation and topical delivery into barrier-deficient skin.

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 the Application and Impact of MicroRNAs as Therapies for Skin Disease

The advent of RNA interference (RNAi) technology has profoundly impacted molecular biology research and medicine but has also advanced the field of skin care. Both effector molecules of RNAi, short-interfering RNA molecules and microRNAs (miRNAs), have been explored for their relative impact and utility for treating a variety of skin conditions. These post-transcriptional RNA regulatory molecules down-modulate protein expression through targeting of the 3' untranslated regions of messenger RNAs, leading to their degradation or repression through sequestration. As researchers hunt for genetic linkages to skin diseases, miRNA regulators have emerged as key players in the biology of keratinocytes, fibroblasts, melanocytes, and other cells of the skin. Herein, we attempt to coalesce the current efforts to combat various skin disorders and diseases through the development of miRNA-based technologies.

Elastic liposomes as novel carriers: recent advances in drug delivery

Elastic liposomes (EL) are some of the most versatile deformable vesicular carriers that comprise physiologically biocompatible lipids and surfactants for the delivery of numerous challenging molecules and have marked advantages over other colloidal systems. They have been investigated for a wide range of applications in pharmaceutical technology through topical, transdermal, nasal, and oral routes for efficient and effective drug delivery. Increased drug encapsulation efficiency, enhanced drug permeation and penetration into or across the skin, and ultradeformability have led to widespread interest in ELs to modulate drug release, permeation, and drug action more efficiently than conventional drug-release vehicles. This review provides insights into the versatile role that ELs play in the delivery of numerous drugs and biomolecules by improving drug release, permeation, and penetration across the skin as well as stability. Furthermore, it provides future directions that should ensure the widespread use of ELs across all medical fields.

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.

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.

Targeted si-RNA with liposomes and exosomes (extracellular vesicles): How to unlock the potential

The concept of RNA interference therapeutics has been initiated 18 years ago, and the main bottleneck for translation of the technology into therapeutic products remains the delivery of functional RNA molecules into the cell cytoplasm. In the present review article after an introduction about the theoretical basis of RNAi therapy and the main challenges encountered for its realization, an overview of the different types of delivery systems or carriers, used as potential systems to overcome RNAi delivery issues, will be provided. Characteristic examples or results obtained with the most promising systems will be discussed. Focus will be given mostly on the applications of liposomes or other types of lipid carriers, such as exosomes, towards improved delivery of RNAi to therapeutic targets. Finally the approach of integrating the advantages of these two vesicular systems, liposomes and exosomes, as a potential solution to realize RNAi therapy, will be proposed.

Dermal/transdermal delivery of small interfering RNA and antisense oligonucleotides- advances and hurdles

A diverse array of nucleic acids has been studied by several researchers for the management of several diseases. Among these compounds, small interfering RNA and antisense oligonucleotides have attracted considerable attention. Antisense oligonucleotides are synthetic single stranded strings of nucleic acids that bind to RNA and thereby alter or reduce expression of the target RNA while siRNAs, on the other hand, are double-stranded RNA molecules which can hybridize with a specific mRNA sequence and block the translation of numerous genes. One of the main obstacles in the dermal or transdermal delivery of these compounds is their low skin permeability. In this review, various techniques used to enhance the delivery of these molecules into or across the skin are described and in some cases, the correlation between enhanced dermal/transdermal delivery and therapeutic efficacy is highlighted.

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.

Design, synthesis and evaluation of VEGF-siRNA/CRS as a novel vector for gene delivery

Small interfering RNA (siRNA) delivery is a prospective method in gene therapy, but it has application limitations such as negative charge, water solubility and high molecular weight. In this study, a safe and efficient nano-vector, CRS, was designed and synthesized to facilitate siRNA delivery. Physical and chemical properties of VEGF-siRNA/CRS were characterized by methods including scanning electron microscopy (SEM), transmission electron microscopy, zeta potential (ζ) measurement, drug-releasing rate measurement, gel electrophoresis and confocal microscopy. The biological activities were evaluated using cell viability assay, gene-silencing efficacy assay in vitro, real-time polymerase chain reaction, enzyme-linked immunosorbent assay (ELISA) and antitumor tests in vivo. The mean nanoparticle size of VEGF-siRNA/CRS was 121.4±0.3 nm with positive ζ potential of 7.69±4.47 mV. The release rate of VEGF-siRNA from VEGF-siRNA/CRS was 82.50% sustained for 48 h in Tris-ethylenediaminetetraacetic acid buffer (pH 8.0). Real-time polymerase chain reaction was used to analyze the efficiency of the transfection, and the result showed that VEGF mRNA expression had been knocked down by 82.36%. The expression of VEGF protein was also recorded to be downregulated to 14.83% using ELISA. The results of cytotoxicity measured by Cell Counting Kit-8 assay showed that VEGF-siRNA/CRS had significant inhibitory effect on HeLa cells. The results of antitumor assays indicated that VEGF-siRNA/CRS exhibited tumor cell growth inhibition in vivo. The results demonstrated that VEGF-siRNA could be delivered and transported by the designed carrier, while siRNA could be released constantly and led to an increasing gene-silencing effect against VEGF gene. In conclusion, VEGF-siRNA/CRS is a promising carrier for siRNA delivery, and further studies are warranted.

Topically applied lipid- and surfactant-based nanoparticles in the treatment of skin disorders

INTRODUCTION

In the treatment of dermatological disorders, topical drug administration is a mainstay. However, nanoparticle-based carrier systems could improve and expand the current therapeutic range via localized delivery of active ingredients. Areas covered: This review gives a detailed description of lipid- and surfactant-based drug delivery systems which have been explored for topical drug administration. To guide researchers in their choice of delivery system, an informative decision tree is included. Moreover, this review provides a complete overview of the topical or transdermal drug products, currently on the market or under clinical investigation, delivered via the discussed carriers, in the treatment of skin disorders. Expert opinion: Conventional liposomes are still popular in the domain of topical or transdermal drug delivery and dominate the market landscape. However, several other carriers, such as exosomes and niosomes, are being explored which offer distinct advantages over liposomes and should therefore not be disregarded when selecting a proper drug delivery system.

Characterization data on the topical carrier DDC642

This article contains original data, figures and methods used in the characterization of the liposomal carrier ‘DDC642’ for topical applications, described in “An elastic liposomal formulation for RNAi-based topical treatment of skin disorders: proof-of-concept in the treatment of psoriasis” (Desmet et al., 2016) [1]. Several elastic liposomal formulations have been evaluated for their ability to encapsulate and deliver RNA interference (RNAi) molecules to cultured primary skin cells. The efficiency and effectiveness of these liposomes were compared to that of our previously characterized liposomes, the ‘SECosomes’ (SEC) (Geusens et al., 2010) [2]. After selection of a potential superior carrier, based on encapsulation and transfection efficiency data (Desmet et al., 2016) [1], the selected DDC642 liposomes were characterized more in-depth. Herein, a detailed characterization of the DDC642 liposome and RNAi-loaded lipoplexes is given, including the matching protocols.