Noninvasive approach for enhancing small interfering RNA delivery percutaneously

An ionic liquid-based delivery system of small interfering RNA targeting Bcl-2 for melanoma therapy

Melanoma, characterized by rapid tumour progression and a strong tendency to metastasize, poses significant challenges in clinical treatment. Given the vital role of B-cell lymphoma 2 (Bcl-2) protein overexpression in inhibiting apoptosis in tumour cells, the suppression of Bcl-2 has emerged as a promising anticancer therapy. Here, we have developed a straightforward and effective delivery system that combines small interfering RNA (siRNA) targeting Bcl-2 (siBcl-2) with ionic liquids (ILs) for treating melanoma. The unique properties of ILs including structural tunability, inherent charge, and chemical stability have garnered significant attention in the biomedical fields; however, their application in siRNA delivery remains nascent. Rather than the weak function of free siBcl-2, our delivery system (1-hexyl-3-methylimidazolium-siBcl-2, designated as C6-siBcl-2) demonstrated an outstanding capacity to improve the cellular uptake and lysosomal escape, resulting in robust apoptosis and cytotoxicity in melanoma cells. In addition to exhibiting superior gene silencing activity in vitro, such events were also evident in mice bearing melanoma tumours. In particular, this IL-based delivery system showed advantages in suppressing tumour growth, preventing metastasis, and enhancing the survival time of mice with melanoma tumours. Therefore, our study offered a novel and powerful nanoplatform that integrated ILs and RNA interference therapy, presenting new strategies for cancer treatment.

Advancements in Transdermal Drug Delivery Systems: Harnessing the Potential of Macromolecular Assisted Permeation Enhancement and Novel Techniques

Transdermal drug delivery (TDD) represents a transformative paradigm in drug administration, offering advantages such as controlled drug release, enhanced patient adherence, and circumvention of hepatic first-pass metabolism. Despite these benefits, the inherent barrier function of the skin, primarily attributed to the stratum corneum, remains a significant impediment to the efficient permeation of therapeutic agents. Recent advancements have focused on macromolecular-assisted permeation enhancers, including carbohydrates, lipids, amino acids, nucleic acids, and cell-penetrating peptides, which modulate skin permeability by transiently altering its structural integrity. Concurrently, innovative methodologies such as iontophoresis, electroporation, microneedles, ultrasound, and sonophoresis have emerged as potent tools to enhance drug transport by creating transient microchannels or altering the skin's microenvironment. Among the novel approaches, the development of nanocarriers such as Liposome, niosomes, and transethosomes etc. has garnered substantial attention. These elastic vesicular systems, comprising lipids and edge activators, exhibit superior skin penetration owing to their deformability and enhanced payload delivery capabilities. Furthermore, the integration of nanocarriers with physical enhancement techniques demonstrates a synergistic potential, effectively addressing the limitations of conventional TDD systems. This comprehensive convergence of macromolecular-assisted enhancers, advanced physical techniques, and next-generation nanocarriers underscores the evolution of TDD, paving the way for optimized therapeutic outcomes.

Anti-CTLA-4 nanobody as a promising approach in cancer immunotherapy

Cancer is one of the most common diseases and causes of death worldwide. Since common treatment approaches do not yield acceptable results in many patients, developing innovative strategies for effective treatment is necessary. Immunotherapy is one of the promising approaches that has been highly regarded for preventing tumor recurrence and new metastases. Meanwhile, inhibiting immune checkpoints is one of the most attractive methods of cancer immunotherapy. Cytotoxic T lymphocyte-associated protein-4 (CTLA-4) is an essential immune molecule that plays a vital role in cell cycle modulation, regulation of T cell proliferation, and cytokine production. This molecule is classically expressed by stimulated T cells. Inhibition of overexpression of immune checkpoints such as CTLA-4 receptors has been confirmed as an effective strategy. In cancer immunotherapy, immune checkpoint-blocking drugs can be enhanced with nanobodies that target immune checkpoint molecules. Nanobodies are derived from the variable domain of heavy antibody chains. These small protein fragments have evolved entirely without a light chain and can be used as a powerful tool in imaging and treating diseases with their unique structure. They have a low molecular weight, which makes them smaller than conventional antibodies while still being able to bind to specific antigens. In addition to low molecular weight, specific binding to targets, resistance to temperature, pH, and enzymes, high ability to penetrate tumor tissues, and low toxicity make nanobodies an ideal approach to overcome the disadvantages of monoclonal antibody-based immunotherapy. In this article, while reviewing the cellular and molecular functions of CTLA-4, the structure and mechanisms of nanobodies' activity, and their delivery methods, we will explain the advantages and challenges of using nanobodies, emphasizing immunotherapy treatments based on anti-CTLA-4 nanobodies.

Small interfering RNA-based nanotherapeutics for treating skin-related diseases

INTRODUCTION

RNA interference (RNAi) has demonstrated great potential in treating skin-related diseases, as small interfering RNA (siRNA) can efficiently silence specific genes. The design of skin delivery systems for siRNA is important to protect the nucleic acid while facilitating both skin targeting and cellular ingestion. Entrapment of siRNA into nanocarriers can accomplish these aims, contributing to improved targeting, controlled release, and increased transfection.

AREAS COVERED

The siRNA-based nanotherapeutics for treating skin disorders are summarized. First, the mechanisms of RNAi are presented, followed by the introduction of challenges for skin therapy. Then, the different nanoparticle types used for siRNA skin delivery are described. Subsequently, we introduce the mechanisms of how nanoparticles enhance siRNA skin penetration. Finally, the current investigations associated with nanoparticulate siRNA application in skin disease management are reviewed.

EXPERT OPINION

The potential application of nanotherapeutic RNAi allows for a novel skin application strategy. Further clinical studies are required to confirm the findings in the cell-based or animal experiments. The capability of large-scale production and reproducibility of nanoparticle products are also critical for translation to commercialization. siRNA delivery by nanocarriers should be optimized to attain cutaneous targeting without the risk of toxicity.

Transdermal delivery via medical device technologies

INTRODUCTION

Despite their effectiveness and indispensability, many drugs are poorly solvated in aqueous solutions. Over recent decades, the need for targeted drug delivery has led to the development of pharmaceutical formulations with enhanced lipid solubility to improve their delivery properties. Therefore, a dependable approach for administering lipid-soluble drugs needs to be developed.

AREAS COVERED

The advent of 3D printing or additive manufacturing (AM) has revolutionized the development of medical devices, which can effectively enable the delivery of lipophilic drugs to the targeted tissues. This review focuses on the use of microneedles and iontophoresis for transdermal drug delivery. Microneedle arrays, inkjet printing, and fused deposition modeling have emerged as valuable approaches for delivering several classes of drugs. In addition, iontophoresis has been successfully employed for the effective delivery of macromolecular drugs.

EXPERT OPINION

Microneedle arrays, inkjet printing, and fused deposition are potentially useful for many drug delivery applications; however, the clinical and commercial adoption rates of these technologies are relatively low. Additional efforts is needed to enable the pharmaceutical community to fully realize the benefits of these technologies.

Laser-assisted nanoparticle delivery to promote skin absorption and penetration depth of retinoic acid with the aim for treating photoaging

Retinoic acid (RA) is an approved treatment for skin photoaging induced by ultraviolet (UVA). Topically applied RA is mainly located in the stratum corneum (SC) with limited diffusion into the deeper strata. A delivery system capable of facilitating dermal delivery and cellular internalization for RA is critical for a successful photoaging therapy. Two delivery approaches, namely nanoparticles and laser ablation, were combined to improve RA's absorption efficacy and safety. The nanoparticle absorption enhancement by the lasers was compared between full-ablative (Er:YAG) and fractional (CO₂) modalities. We fabricated poly-L-lactic acid (PLA) and PLA/poly(lactic-co-glycolic acid) (PLGA) nanoparticles by an emulsion-solvent evaporation technique. The mean size of PLA and PLA/PLGA nanocarriers was 237 and 222 nm, respectively. The RA encapsulation percentage in both nanosystems was > 96 %. PLA and PLA/PLGA nanocarriers promoted RA skin deposition by 5- and 3-fold compared to free control. The ablative lasers further enhanced the skin deposition of RA-loaded nanoparticles, with the full-ablative laser showing greater permeation enhancement than the fractional mode. The skin biodistribution assay evaluated by confocal and fluorescence microscopies demonstrated that the laser-assisted nanoparticle delivery achieved a significant dermis and follicular accumulation. The cell-based study indicated a facile uptake of the nanoparticles into the human dermal fibroblasts. The nanoparticulate RA increased type I collagen and elastin production in the UVA-treated fibroblasts. A reduction of matrix metalloproteinase (MMP)-1 was also highlighted in the photoaging cells. The calculation of therapeutic index (TI) by multiplying collagen/elastin elevation percentage and skin deposition predicted better anti-photoaging performance in Er:YAG laser-assisted nanoparticle delivery than CO₂ laser. Nanoencapsulation of RA decreased the cytotoxicity against skin fibroblasts. In vivo skin tolerance test on a nude mouse showed less skin damage after topical application of the nanoparticles than free RA. Our results hypothesized that the laser-mediated nanoparticle delivery provided an efficient and safe use for treating photoaging.

Nanoencapsulation of Tea Catechins for Enhancing Skin Absorption and Therapeutic Efficacy

Tea catechins are a group of flavonoids that show many bioactivities. Catechins have been extensively reported as a potential treatment for skin disorders, including skin cancers, acne, photoaging, cutaneous wounds, scars, alopecia, psoriasis, atopic dermatitis, and microbial infection. In particular, there has been an increasing interest in the discovery of cosmetic applications using catechins as the active ingredient because of their antioxidant and anti-aging activities. However, active molecules with limited lipophilicity have difficulty penetrating the skin barrier, resulting in low bioavailability. Nevertheless, topical application is a convenient method for delivering catechins into the skin. Nanomedicine offers an opportunity to improve the delivery efficiency of tea catechins and related compounds. The advantages of catechin-loaded nanocarriers for topical application include high catechin loading efficiency, sustained or prolonged release, increased catechin stability, improved bioavailability, and enhanced accumulation or targeting to the nidus. Further, various types of nanoparticles, including liposomes, niosomes, micelles, lipid-based nanoparticles, polymeric nanoparticles, liquid crystalline nanoparticles, and nanocrystals, have been employed for topical catechin delivery. These nanoparticles can improve catechin permeation via close skin contact, increased skin hydration, skin structure disorganization, and follicular uptake. In this review, we describe the catechin skin delivery approaches based on nanomedicine for treating skin disorders. We also provide an in-depth description of how nanoparticles effectively improve the skin absorption of tea catechins and related compounds, such as caffeine. Furthermore, we summarize the possible future applications and the limitations of nanocarriers for topical delivery at the end of this review article.

Laser-assisted nanocarrier delivery to achieve cutaneous siRNA targeting for attenuating psoriasiform dermatitis

Psoriasis is an autoimmune skin disorder presenting the excessive expression of interleukin (IL)-6. The topical use of small interfering RNA (siRNA) has been increasingly discovered for treating skin diseases. A delivery system capable of protecting siRNA while facilitating both skin targeting and cellular entrance is critical for the successful medication of topically-applied siRNA. Herein, we developed a delivery system for siRNA based on poly(lactic-co-glycolic acid) (PLGA) nanoparticles and combined this system with an ablative laser to promote skin absorption for topical psoriasis therapy. The siRNA absorption enhancement was compared by two laser modalities: a fractional CO₂ laser and a fully-ablative Er:YAG laser. We characterized the effect of the delivery system by the cellular uptake, IL-6 silencing, in vitro skin absorption, cutaneous biodistribution, and in vivo psoriasiform dermatitis in mice. The nanocarriers showed minimal cytotoxicity and facile cellular uptake to knock down the IL-6 expression. The nanoformulation containing a cationic surfactant (Forestall) for ion pairing with siRNA achieved a 66% and 77% IL-6 knockdown efficiency toward keratinocytes and macrophages, respectively. In the Franz cell absorption, the lasers increased the naked siRNA penetration to the receptor compartment by 3.7-5.0-fold but remarkably reduced skin deposition using imiquimod (IMQ)-treated psoriasiform skin as the barrier. The fractional laser facilitated nanoparticle-associated siRNA skin deposition up to 3.3-fold, whereas the transport of the nanocarriers to the receptor was negligible. Qualitatively, the lasers increased nanoparticle delivery in the epidermis with limited effect to elevate the penetration depth. The fractional-mediated nanocarrier delivery dramatically attenuated the erythema and scaly lesions of psoriasiform dermatitis. The histological examination displayed a reduction of epidermal hyperplasia and macrophage infiltration by the combination of laser and nanosystem. The passive and laser-assisted naked siRNA delivery was less effective in mitigating dermatitis. The topical delivery of fractional laser-assisted nanoparticles on mice resulted in a 56% IL-6 knockdown. Our results manifested the benefit of cutaneous siRNA targeting using ablative lasers to deliver nanocarriers for treating psoriatic inflammation.

Iontophoresis of Biological Macromolecular Drugs

Over the last few decades, biological macromolecular drugs (e.g., peptides, proteins, and nucleic acids) have become a significant therapeutic modality for the treatment of various diseases. These drugs are considered superior to small-molecule drugs because of their high specificity and favorable safety profiles. However, such drugs are limited by their low oral bioavailability and short half-lives. Biological macromolecular drugs are typically administrated via invasive methods, e.g., intravenous or subcutaneous injections, which can be painful and induce needle phobia. Noninvasive transdermal delivery is an alternative administration route for the local and systemic delivery of biological macromolecular drugs. However, a challenge with the noninvasive transdermal delivery of biological macromolecular drugs is the outermost layer of the skin, known as the stratum corneum, which is a physical barrier that restricts the entry of extraneous macromolecules. Iontophoresis (IP) relies on the application of a low level of electricity for transdermal drug delivery, in order to facilitate the skin permeation of hydrophilic and charged molecules. The IP of several biological macromolecular drugs has recently been investigated. Herein, we review the IP-mediated noninvasive transdermal delivery of biological macromolecular drugs, their routes of skin permeation, their underlying mechanisms, and their advance applications.

Polymeric Nanoparticles for Transdermal Delivery of Polyphenols

Polyphenols comprises of a large group of naturally occurring plant secondary metabolites having various nutritional and health benefits. They are safe and are found abundantly in the diet. Current research on polyphenols focuses on their mechanism and their benefits on the human health. However, due to their low solubility and bioavailability, delivery from conventional route has been a challenge and their translation into clinical applications has been limited. Topical and transdermal delivery of polymeric nanoparticles will act as a novel therapeutic approach for promising delivery of polyphenols. In this review, we have evaluated the existing scientific literature and summarized the potential use of polymeric nanoparticles as a carrier for polyphenolic compounds for delivery via topical and transdermal routes for the treatment of skin cancers such as melanoma.

Electroporation-enhanced transdermal drug delivery: Effects of logP, pKa, solubility and penetration time

Electroporation is an important physical technique to improve drug transdermal delivery, although its mechanism remains unclear. Here, some types of polar drugs, including aspirin, diclofenac sodium, metformin hydrochloride, ibuprofen and zidovudine, were used as the model drugs for the exploration of electroporation mechanisms. Electroporation had great influences on the structure of stratum corneum to improve the cumulative permeability due to the formation of pores maintaining for at least 2 h, depending on the power and time, and then the permeation gradually recovered to the normal value after 12 h. A mathematical model was firstly established to exhibit the relationship between the electroporation-improving cumulative permeation and the physiochemical properties of the model drugs, involving oil-water partition coefficient (logP), dissociation constant (pKa) and solubility (S). Increased cumulative permeation depended on increased S, decreased logP and pKa. Electroporation is an effective physical technique to improve transdermal drug delivery depending on itself and the properties of drugs.

Amelioration of lung ischemia‑reperfusion injury by JNK and p38 small interfering RNAs in rat pulmonary microvascular endothelial cells in an ischemia‑reperfusion injury lung transplantation model

The inhibition of mitogen‑activated protein kinases (MAPKs), including c‑Jun NH2‑terminal protein kinase (JNK), p38 MAPK (p38) and extracellular signal‑regulated protein kinase 1/2 (ERK1/2), have an important effect on lung ischemia‑reperfusion injury (IRI) during lung transplantation (LT). However, the way in which combined MAPK inhibition exerts optimal protective effects on lung IRI remains to be elucidated. Therefore, the present study evaluated the therapeutic efficacy of the inhibition of MAPKs in rat pulmonary microvascular endothelial cells (PMVECs) in an IRI model of LT. The rat PMVECs were transfected with small interfering RNAs (siRNAs) against JNK, p38 or ERK1/2. Cotransfection was performed with siRNAs against JNK and p38 in the J+p group, JNK and ERK1/2 in the J+E group, p38 and ERK1/2 in the p+E group, or all three in the J+p+E group. Non‑targeting (NT) siRNA was used as a control. The PMVECs were then treated to induce IRI, and the levels of inflammation, apoptosis and oxidative stress were detected. Differences between compared groups were determined using Tukey's honest significant difference test. In all groups, silencing of the MAPKs was shown to attenuate inflammation, apoptosis and oxidative stress to differing extents, compared with the NT group. The J+p and J+p+E groups showed lower levels of interleukin (IL)‑1β, IL‑6 and malondialdehyde, a lower percentage of early‑apoptotic cells, and higher superoxide dismutase (SOD) activity, compared with the other groups. No significant differences were observed in the inflammatory response, SOD activity or early apoptosis between the J+p and J+p+E groups. These findings suggested that the dual inhibition of JNK and p38 led to maximal amelioration of lung IRI in the PMVECs of the IRI model of LT, which occurred through anti‑inflammatory, anti‑oxidative and anti‑apoptotic mechanisms.