Enhanced skin penetration of P20 phosphopeptide using protein transduction domains

Emerging Approaches for Enabling RNAi Therapeutics

RNA interference (RNAi) is a primitive evolutionary mechanism developed to escape incorporation of foreign genetic material. siRNA has been instrumental in achieving the therapeutic potential of RNAi by theoretically silencing any gene of interest in a reversible and sequence-specific manner. Extrinsically administered siRNA generally needs a delivery vehicle to span across different physiological barriers and load into the RISC complex in the cytoplasm in its functional form to show its efficacy. This review discusses the designing principles and examples of different classes of delivery vehicles that have proved to be efficient in RNAi therapeutics. We also briefly discuss the role of RNAi therapeutics in genetic and rare diseases, epigenetic modifications, immunomodulation and combination modality to inch closer in creating a personalized therapy for metastatic cancer. At the end, we present, strategies and look into the opportunities to develop efficient delivery vehicles for RNAi which can be translated into clinics.

Topical Application of Peptide-Chondroitin Sulfate Nanoparticles Allows Efficient Photoprotection in Skin

In this article, we describe a method of delivery of chondroitin sulfate to skin as nanoparticles and demonstrate its anti-inflammatory and antioxidant role using UV irradiation as a model condition. These nanoparticles, formed through electrostatic interactions of chondroitin sulfate with a skin-penetrating peptide, were found to be homogenous with positive surface charges and stable at physiological and acidic pH under certain conditions. They were able to enter into the human keratinocyte cell line (HaCaT), artificial skin membrane (mimicking the human skin), and mouse skin tissue unlike free chondroitin sulfate. The preapplication of nanoparticles also exhibited reduced levels of oxidative stress, cyclobutane pyrimidine dimer formation, TNF-α, and so on in UV-B-irradiated HaCaT cells. In an acute UV-B irradiation mouse model, their topical application resulted in reduced epidermal thickness and sunburn cells, unlike in the case of free chondroitin sulfate. Thus, a completely noninvasive method was used to deliver a bio-macromolecule into the skin without using injections or abrasive procedures.

Preparation and in vivo evaluation of a topical hydrogel system incorporating highly skin-permeable growth factors, quercetin, and oxygen carriers for enhanced diabetic wound-healing therapy

PURPOSE

We created and evaluated an enhanced topical delivery system featuring a combination of highly skin-permeable growth factors (GFs), quercetin (QCN), and oxygen; these synergistically accelerated re-epithelialization and granulation tissue formation of/in diabetic wounds by increasing the levels of GFs and antioxidants, and the oxygen partial pressure, at the wound site.

METHODS

To enhance the therapeutic effects of exogenous administration of GFs for the treatment of diabetic wounds, we prepared highly skin-permeable GF complexes comprised of epidermal growth factor (EGF), insulin-like growth factor-I (IGF-I), platelet-derived growth factor-A (PDGF-A), and basic fibroblast growth factor (bFGF), genetically attached, via the N-termini, to a low-molecular-weight protamine (LMWP) to form LMWP-EGF, LMWP-IGF-I, LMWP-PDGF-A, and LMWP-bFGF, respectively. Furthermore, quercetin (QCN)- and oxygen-carrying 1-bromoperfluorooctane (PFOB)-loaded nanoemulsions (QCN-NE and OXY-PFOB-NE) were developed to improve the topical delivery of QCN and oxygen, respectively. After confirming the enhanced penetration of LMWP-GFs, QCN-NE, and oxygen delivered from OXY-PFOB-NE across human epidermis, we evaluated the effects of combining LMWP-GFs, QCN-NE, and OXY-PFOB-NE on proliferation of keratinocytes and fibroblasts, and the chronic wound closure rate of a diabetic mouse model.

RESULTS

The optimal ratios of LMWP-EGF, LMWP-IGF-I, LMWP-PDGF-A, LMWP-bFGF, QCN-NE, and OXY-PFOB-NE were 1, 1, 0.02, 0.02, 0.2, and 60, respectively. Moreover, a Carbopol hydrogel containing LMWP-GFs, QCN-NE, and OXY-PFOB-NE (LMWP-GFs/QCN-NE/OXY-PFOB-NE-GEL) significantly improved scratch-wound recovery of keratinocytes and fibroblasts in vitro compared to that afforded by hydrogels containing each component alone. LMWP-GFs/QCN-NE/OXY-PFOB-NE-GEL significantly accelerated wound-healing in a diabetic mouse model, decreasing wound size by 54 and 35% compared to the vehicle and LMWP-GFs, respectively.

CONCLUSION

LMWP-GFs/QCN-NE/OXY-PFOB-NE-GEL synergistically accelerated the healing of chronic wounds, exerting both rapid and prolonged effects.

De Novo Molecular Design of a Novel Octapeptide That Inhibits In Vivo Melanogenesis and Has Great Transdermal Ability

Cutaneous hyperpigmentation from excess melanogenesis causes serious pigmentary disorders and even melasma. Short peptides (SPs) are garnering attention lately owing to their therapeutic potential in dermatological diseases and low systemic side effects. Here, we show an octapeptide, ansin2, designed de novo from antioxidant SPs we previously reported, significantly inhibiting melanogenesis in B16 cells by decreasing tyrosinase production via regulating the MITF pathway. Ansin2 could also inhibit tyrosinase function by covering its catalytic pocket, which was simulated in docking and LIGPLOT studies. Topical application of ansin2 exhibited evident protection in UVB-induced pigmentation in guinea pig models both in terms of prophylaxis and treatment. Interestingly, unlike other hydrophilic and peptidic drugs that need delivery systems, ansin2 can be efficiently delivered topically to the epidermis and dermis per se without an affiliated moiety. Given that ansin2 lacks unwanted toxicities and immunogenicity, it holds great potential in treating hyperpigmentation in the cosmetics and pharmaceutical industries.

Targeted Delivery of Cell Penetrating Peptide Virus-like Nanoparticles to Skin Cancer Cells

Skin cancer or cutaneous carcinoma, is a pre-eminent global public health problem with no signs of plateauing in its incidence. As the most common treatments for skin cancer, surgical resection inevitably damages a patient’s appearance, and chemotherapy has many side effects. Thus, the main aim of this study was to screen for a cell penetrating peptide (CPP) for the development of a targeting vector for skin cancer. In this study, we identified a CPP with the sequence NRPDSAQFWLHH from a phage displayed peptide library. This CPP targeted the human squamous carcinoma A431 cells through an interaction with the epidermal growth factor receptor (EGFr). Methyl-β-cyclodextrin (MβCD) and chlorpromazine hydrochloride (CPZ) inhibited the internalisation of the CPP into the A431 cells, suggesting the peptide entered the cells via clathrin-dependent endocytosis. The CPP displayed on hepatitis B virus-like nanoparticles (VLNPs) via the nanoglue successfully delivered the nanoparticles into A431 cells. The present study demonstrated that the novel CPP can serve as a ligand to target and deliver VLNPs into skin cancer cells.

Functionalised nanostructures for transdermal delivery of drug cargos

Nanotechnology has burgeoned over last decade exploring varieties of novel applications in all areas of science and technology. Utilisation of bio-friendly polymers for engineering nanostructures (NS) improves safety and efficacy in drug delivery. Biopolymers not merely employed for fabricating drug carriers but also leveraged for surface functionalisation of other NS to impart bio-mimicking properties. Biopolymer functionalised NS garnered researcher's attention because of their potential to enhance skin permeability of drug cargo. Biopolymers, i.e. cell-penetrating peptides (CPP), chitosan and hyaluronic acid not only enhance skin permeability but also add multiple functions due to their intrinsic biomimetic properties. This multifunctional drug delivery system is a promising tool to achieve skin delivery of large number of therapeutic agents. In this review, functionalisation of NS with biopolymers particularly polysaccharides and polypeptides is discussed in detail. In particular, applications of these functionalised NS for TDDS is elaborated. Moreover, this review provides framework for elaborating importance of functionalisation of NS to enhance skin permeability and depicts advantages of biopolymers to construct more biocompatible carriers for drug cargos.

Chemical penetration enhancers

To achieve an efficient skin penetration of most compounds it is necessary to overcome the barrier function of the skin, provided mainly (but not only) by the stratum corneum. Among various strategies used or studied to date, chemical penetration enhancers are the most frequently employed with one of the longest histories of use. There is a multitude of agents described as penetration enhancers, and they present varying properties and structures. In this manuscript, we aim to provide a brief overview of traditional enhancers and some of their properties, focusing on the benefits of combination of chemical enhancers and on selected novel compounds that have shown promise to increase drug delivery into/across the skin.

A rhenium tris-carbonyl derivative as a model molecule for incorporation into phospholipid assemblies for skin applications

A rhenium tris-carbonyl derivative (fac-[Re(CO)3Cl(2-(1-dodecyl-1H-1,2,3,triazol-4-yl)-pyridine)]) was incorporated into phospholipid assemblies, called bicosomes, and the penetration of this molecule into skin was monitored using Fourier-transform infrared microspectroscopy (FTIR). To evaluate the capacity of bicosomes to promote the penetration of this derivative, the skin penetration of the Re(CO)3 derivative dissolved in dimethyl sulfoxide (DMSO), a typical enhancer, was also studied. Dynamic light scattering results (DLS) showed an increase in the size of the bicosomes with the incorporation of the Re(CO)3 derivative, and the FTIR microspectroscopy showed that the Re(CO)3 derivative incorporated in bicosomes penetrated deeper into the skin than when dissolved in DMSO. When this molecule was applied on the skin using the bicosomes, 60% of the Re(CO)3 derivative was retained in the stratum corneum (SC) and 40% reached the epidermis (Epi). Otherwise, the application of this molecule via DMSO resulted in 95% of the Re(CO)3 derivative being in the SC and only 5% reaching the Epi. Using a Re(CO)3 derivative with a dodecyl-chain as a model molecule, it was possible to determine the distribution of molecules with similar physicochemical characteristics in the skin using bicosomes. This fact makes these nanostructures promising vehicles for the application of lipophilic molecules inside the skin.

An easy-to-detect nona-arginine peptide for epidermal targeting

A nona-arginine peptide conjugated with a Re-tricarbonyl IR and fluorescent probe (SCoMPI) accumulates at the epidermis without reaching the dermis.

Cationic membrane-active peptides - anticancer and antifungal activity as well as penetration into human skin

Cationic antimicrobial peptides are ancient natural broad-spectrum antibiotics, and several compounds also exhibit anticancer activity. However, most applications pertain to bacterial infections, and treatment for skin cancer is less frequently considered. The cytotoxicity of melittin, cecropin A, protegrin-1 and histatin 5 against squamous skin cancer cell lines and normal human keratinocytes was evaluated and compared to established drugs. The results show that melittin clearly outperforms 5-fluorouracil regarding antitumor activity. Importantly, combined melittin and 5-fluorouracil enhanced cytotoxic effects on cancer cells and reduced toxicity on normal keratinocytes. Additionally, minimum inhibitory concentrations indicate that melittin also shows superior activity against clinical and laboratory strains of Candida albicans compared to amphotericin B. To evaluate its potential for topical applications, human skin penetration of melittin was investigated ex vivo and compared to two non-toxic cell-penetrating peptides (CPPs), low molecular weight protamine (LMWP) and penetratin. The stratum corneum prevents penetration into viable epidermis over 6 h; however, the peptides gain access to the viable skin after 24 h. Inhibition of digestive enzymes during skin penetration significantly enhances the availability of intact peptide. In conclusion, melittin may represent an innovative agent for non-melanoma skin cancer and infectious skin diseases. In order to develop a drug candidate, skin absorption and proteolytic digestion by skin enzymes need to be addressed.

Potent enhancement of transdermal absorption and stability of human tyrosinase plasmid (pAH7/Tyr) by Tat peptide and an entrapment in elastic cationic niosomes

Enhancement of transdermal absorption through rat skin and stability of the human tyrosinase plasmid (P) using Tat (T) and an entrapment in elastic cationic niosomes (E) were described. E (Tween61:cholesterol:DDAB at 1:1:0.5 molar ratio) were prepared by the freeze-dried empty liposomes (FDELs) method using 25% ethanol. TP was prepared by a simple mixing method. TPE was prepared by loading T and P in E at the T:P:E ratio of 0.5:1:160 w/w/w. For gel formulations, P, TP, PE and TPE were incorporated into Carbopol 980 gel (30 µg of plasmid per 1 g of gel). For the transdermal absorption studies, the highest cumulative amounts and fluxes of the plasmid in viable epidermis and dermis (VED) were observed from the TPE of 0.31 ± 0.04 µg/cm(2) and 1.86 ± 0.24 µg/cm(2)/h (TPE solution); and 4.29 ± 0.40 µg/cm(2) and 25.73 ± 2.40 µg/cm(2)/h (TPE gel), respectively. Only plasmid from the PE and TPE could be found in the receiving solution with the cumulative amounts and fluxes at 6 h of 0.07 ± 0.01 µg/cm(2) and 0.40 ± 0.08 µg/cm(2)/h (PE solution); 0.10 ± 0.01 µg/cm(2) and 0.60 ± 0.06 µg/cm(2)/h (TPE solution); 0.88 ± 0.03 µg/cm(2) and 5.30 ± 0.15 µg/cm(2)/h (PE gel); and 1.02 ± 0.05 µg/cm(2) and 6.13 ± 0.28 µg/cm(2)/h (TPE gel), respectively. In stability studies, the plasmid still remained at 4 ± 2 °C and 25 ± 2 °C of about 48.00-65.20% and 27.40-51.10% (solution); and 12.34-38.31% and 8.63-36.10% (gel), respectively, whereas at 45 ± 2 °C, almost all the plasmid was degraded. These studies indicated the high potential application of Tat and an entrapment in elastic cationic niosomes for the development of transdermal gene delivery system.

(31)P solid-state NMR based monitoring of permeation of cell penetrating peptides into skin

The main objective of the current study was to investigate penetration of cell penetrating peptides (CPPs: TAT, R8, R11, and YKA) through skin intercellular lipids using (31)P magic angle spinning (MAS) solid-state NMR. In vitro skin permeation studies were performed on rat skin, and sections (0-60, 61-120, and 121-180μm) were collected and analyzed for (31)P NMR signal. The concentration-dependent shift of 0, 25, 50, 100, and 200mg/ml of TAT on skin layers, diffusion of TAT, R8, R11, and YKA in the skin and time dependent permeation of R11 was measured on various skin sections using (31)P solid-state NMR. Further, CPPs and CPP-tagged fluorescent dye encapsulate liposomes (FLip) in skin layers were tagged using confocal microscopy. The change in (31)P NMR chemical shift was found to depend monotonically on the amount of CPP applied on skin, with saturation behavior above 100mg/ml CPP concentration. R11 and TAT caused more shift in solid-state NMR peaks compared to other peptides. Furthermore, NMR spectra showed R11 penetration up to 180μm within 30min. The results of the solid-state NMR study were in agreement with confocal microscopy studies. Thus, (31)P solid-state NMR can be used to track CPP penetration into different skin layers.

Alleviation of abnormal synaptic neurotransmitter release by cell-permeable form of the truncated SNAP-25 upon transcutaneous delivery

Abnormal releases of neurotransmitters result in movement disorders such as dystonia, chorea, tics, blepharospasm and wrinkle formation, and intra-muscular injection of Botulinum neurotoxin is widely used for the treatment of these complications. But it is potentially poisonous and must be intra-muscularly injected with precision by a well-trained physician. For novel therapeutic development with high safety profile and easy skin penetration for these complications, we generated Trans-X, a cell permeable form of the truncated SNAP-25 that is one of the SNARE complex for vesicle exocytosis of neuron. Upon topical administration, Trans-X efficiently penetrated through skin, reached the dermis layer and remained stable. Trans-X, which did not show any ocular or skin allergic sensitivity, can block the pre-synaptic neurotransmitter transport via acting as a competitive inhibitor of SNARE complex formation, and effectively induced muscle paralysis comparable to BOTOX(®) evaluated by measuring compound muscle action potential. Topical treatment of the facial skin with Trans-X in clinical study can prevent the wrinkle formation and improve the skin roughness. Therefore, our study suggests that Trans-X may be a convenient and effective medical and cosmetic treatment for local management of movement disorder without systemic toxicity.

Protein transduction domain-containing microemulsions as cutaneous delivery systems for an anticancer agent

In this study, we developed cationic microemulsions containing a protein transduction domain (penetratin) for optimizing paclitaxel localization within the skin. Microemulsions were prepared by mixing a surfactant blend (BRIJ:ethanol:propylene glycol 2:1:1, w/w/w) with monocaprylin (oil phase) at 1.3:1 ratio, and adding water at 30% (ME-30), 43% (ME-43), and 50% (ME-50). Electrical conductivity and viscosity measurements indicated that ME-30 is most likely a bicontinuous system, whereas ME-43 and ME-50 are water continuous. Their irritation potential, studied in bioengineered skin equivalents, decreased as aqueous content increased. Because ME-50 was not stable in the presence of paclitaxel (0.5%), ME-43 was selected for penetratin incorporation (0.4%). The microemulsion containing penetratin (ME-P) displayed zeta potential of +5.2 mV, and promoted a 1.8-fold increase in paclitaxel cutaneous (but not transdermal) delivery compared with the plain ME-43, whereas the enhancement promoted by another cationic microemulsion containing phytosphingosine was 1.3-fold. Compared with myvacet oil, ME-P promoted a larger increase on transepidermal water loss (twofold) than the plain or the phytosphingosine-containing microemulsions (1.5-fold), suggesting that penetratin addition increases the barrier-disrupting and penetration-enhancing effects of microemulsions. The ratio Δcutaneous/Δtransdermal delivery promoted by ME-P was the highest among the formulations, suggesting its potential for drug localization within cutaneous tumor lesions.

Preparation and evaluation of lidocaine hydrochloride-loaded TAT-conjugated polymeric liposomes for transdermal delivery

Transactivation transcriptional activator (TAT) peptides were conjugated on the octadecyl-quaternized, lysine-modified chitosan to form polymeric liposomes (TAT-PLs) with cholesterol for improving transdermal delivery of local anesthetic lidocaine hydrochloride (LID). In this study, the LID loaded TAT-conjugated polymeric liposomes (LID-TAT-PLs) have been successfully prepared. LID-TAT-PLs were characterized by determination of their particle size, polydispersity, morphology, drug encapsulation efficiency, drug release behavior in vitro, and storage-stability. The skin permeation of LID-TAT-PLs was examined using a Franz diffusion cell mounted with depilated mouse skin in vitro, and penetration of TAT-PLs was visualized by confocal laser scanning microscopy (CLSM). The results showed that LID-TAT-PLs were spherical in solution, with substantially smaller mean diameter (154.7±10.7 nm), higher encapsulation efficiency (80.05±2.64%) and better stability in contrast to conventional liposomes (CLs). From the in vitro skin permeation results, transdermal flux of LID-TAT-PLs was approximately 4.17 and 1.75 times higher than that of LID solution and LID CLs (P<0.05). CLSM studies also confirmed that TAT-PLs reached viable layers of the skin. Hence, the results indicate that LID-TAT-PLs are effective and potential alternative for the LID transdermal formulation.

Cell-penetrating peptides as a novel transdermal drug delivery system

In the last decade, almost one-third of the newly discovered drugs approved by the US FDA were biomolecules and biologics. Effective delivery of therapeutic biomolecules to their target is a challenging issue. Innovations in drug delivery systems have improved the efficiency of many of new biopharmaceuticals. Designing of novel transdermal delivery systems has been one of the most important pharmaceutical innovations, which offers a number of advantages. The cell-penetrating peptides have been increasingly used to mediate delivery of bimolecular cargoes such as small molecules, small interfering RNA nucleotides, drug-loaded nanoparticles, proteins, and peptides, both in vitro and in vivo, without using any receptors and without causing any significant membrane damage. Among several different drug delivery routes, application of cell-penetrating peptides in the topical and transdermal delivery systems has recently garnered tremendous attention in both cosmeceutical and pharmaceutical research and industries. In this review, we discuss history of cell-penetrating peptides, cell-penetrating peptide/cargo complex formation, and their mechanisms of cell and skin transduction.

Combining poly-arginine with the hydrophobic counter-anion 4-(1-pyrenyl)-butyric acid for protein transduction in transdermal delivery

Topical therapy is the most favored form of treatment for whitening against hyperpigmentation and sunburn because it lends itself to self-administration, patient compliance, and absence of systemic adverse effects. However, transdermal delivery of hydrophilic chemicals is difficult. The main purpose of this study is to develop a delivering system of hydrophilic drugs and proteins across the skin. Hydroquinone (HQ), a well-known tyrosinase inhibitor and antimelanogenesis compound, and enhanced green fluorescent protein (EGFP) were fused with eleven poly-arginine (11R). Both HQ-11R and EGFP-11R were efficiently delivered in B16 cells, a mouse melanoma cell line. HQ-11R was as effective as HQ alone at inhibiting melanin synthesis in B16 cells. EGFP-11R was efficiently delivered into cells of the epidermis with 4-(1-pyrenyl)-butyric acid (PB), a counteranion bearing an aromatic hydrophobic moiety, in vivo, but EGFP alone or EGFP-11R without PB was not. Finally, topical application of HQ-11R with PB significantly inhibited UV irradiation-induced pigmentation in guinea pigs compared with HQ alone. These results suggest that topical therapy using poly-arginine in combination with PB is useful for the delivery of hydrophilic drugs and proteins by the transdermal route.

Transdermal administration of lactoferrin with sophorolipid1This article is part of a Special Issue entitled Lactoferrin and has undergone the Journal's usual peer review process

Lactoferrin (Lf), a multifunctional glycoprotein, is known to activate dermal fibroblasts. Enhancing percutaneous absorption without decreasing the activity of Lf is critical in making the dermal administration of Lf beneficial. Sophorolipid (SL), a glycolipid-type biosurfactant, is known to form assemblies that may elevate the efficiency of the transdermal delivery of active ingredients. Here, we investigated the role of SL in the transdermal absorption of bovine Lf (bLf) and the effect of SL on the bLf activity on dermal fibroblasts. Transdermal absorption of bLf through a model skin was enhanced by 1.3-fold to 1.7-fold when SL was added. The effects of SL on the bLf activities on dermal fibroblasts were examined by cell proliferation activities and by gene expression levels of elastic fiber components, collagen IV, and hyaluronan synthases, revealing that SL did not depress the effect of bLf to any extent. Instead, the tropoelastin gene expression was upregulated ∼60-fold by bLf alone, which was further increased to ∼160-fold by bLf and SL together, suggesting a significant synergism between bLf and SL. Protein levels of elastin, assessed by immunohistochemistry, correlated well with the results of gene expressions. These results indicate the feasibility of the transdermal administration of bLf with SL.

Dermal microdialysis technique to evaluate the trafficking of surface-modified lipid nanoparticles upon topical application

PURPOSE

To evaluate the skin pharmacokinetics and tissue distribution of cell penetrating peptides (CPP) modified nano-structured lipid carrier (NLC) using an in vivo dermal microdialysis (MD) technique.

METHODS

Celecoxib (Cxb) encapsulated NLCs (CXBN), CPP modified CXBN (CXBN-CPP) and Cxb-Solution (CXBS) formulations were prepared and tested for in vitro skin distribution. MD was used to assess pharmacokinetic parameters of Cxb after topical application of Cxb formulations. The effect of pre-treatment with Cxb formulations was evaluated for expression of prostaglandin-E2 (PGE(2)) and Interleukin-6 (IL-6) after exposure of xylene using MD. Allergic contact dermatitis (ACD) model was used to confirm in vivo therapeutic response of Cxb formulations.

RESULTS

The cumulative permeation of Cxb in MD dialysate after 24 h for CXBN-CPP was significantly higher (p < 0.001) than CXBN and CXBS. Further, pre-treatment with CXBN-CPP significantly inhibited PGE(2) and IL-6 expression compared to CXBS and CXBN (p < 0.001). In ACD model, CXBN-CPP showed significant reduction (p < 0.001) in ear thickness compared to controls.

CONCLUSIONS

Surface modification of NLC with CPPs can enhance the skin permeation of Cxb and MD can be used to investigate pharmacokinetics of Cxb nanoparticles in the skin.

Tat peptide-admixed elastic liposomal formulation of hirsutenone for the treatment of atopic dermatitis in NC/Nga mice

BACKGROUND

The aim of the present study was to enhance a topical delivery of hirsutenone (HST), a naturally occuring immunomodulator, employing Tat peptide-admixed elastic liposomes (EL/T).

METHODS

HST-loaded EL, consisting of phosphatidylcholine and Tween 80 (85:15 w/w%), were prepared using thin film hydration method. By adding Tat peptide to EL (0.16 w/w%), EL/T were formulated. The in vitro skin permeation of HST was examined using a Franz diffusion cell mounted with depilated mouse skin. Lesions for atopic dermatitis (AD) were induced by a topical application of diphenylcyclopropenone to NC/Nga mice. Therapeutic improvements of AD were evaluated by clinical skin severity scores. Immunological analyses on inducible nitric oxide synthase and cyclooxygenase-2 levels in the skin and interleukin (IL)-4, IL-13, immunoglobulin E, and eosinophil levels in the blood were also performed.

RESULTS

EL systems were superior to conventional cream, revealing greater flux values in a permeation study. The addition of Tat peptide further increased the skin permeation of HST. In an efficacy study with AD-induced NC/Nga mice, an HST-containing EL/T formulation brought a significant improvement in both skin severity score and immune-related responses for the levels of nitric oxide synthase, cyclooxygenase-2, IL-4, IL-13, immunoglobulin E, and eosinophils.

CONCLUSION

A novel EL/T formulation was successfully developed for topical delivery of HST to treat AD.

Delivery of intracellular-acting biologics in pro-apoptotic therapies

The recent elucidation of molecular regulators of apoptosis and their roles in cellular oncogenesis has motivated the development of biomacromolecular anticancer therapeutics that can activate intracellular apoptotic signaling pathways. Pharmaceutical scientists have employed a variety of classes of biologics toward this goal, including antisense oligodeoxynucleotides, small interfering RNA, proteins, antibodies, and peptides. However, stability in the in vivo environment, tumor-specific biodistribution, cell internalization, and localization to the intracellular microenvironment where the targeted molecule is localized pose significant challenges that limit the ability to directly apply intracellular-acting, pro-apoptotic biologics for therapeutic use. Thus, approaches to improve the pharmaceutical properties of therapeutic biomacromolecules are of great significance and have included chemically modifying the bioactive molecule itself or formulation with auxiliary compounds. Recently, promising advances in delivery of pro-apoptotic biomacromolecular agents have been made using tools such as peptide "stapling", cell penetrating peptides, fusogenic peptides, liposomes, nanoparticles, smart polymers, and synergistic combinations of these components. This review will discuss the molecular mediators of cellular apoptosis, the respective mechanisms by which these mediators are dysregulated in cellular oncogenesis, the history and development of both nucleic-acid and amino-acid based drugs, and techniques to achieve intracellular delivery of these biologics. Finally, recent applications where pro-apoptotic functionality has been achieved through delivery of intracellular-acting biomacromolecular drugs will be highlighted.

Interaction of nanoparticles and cell-penetrating peptides with skin for transdermal drug delivery

Topical or transdermal drug delivery is challenging because the skin acts as a natural and protective barrier. Therefore, several methods have been examined to increase the permeation of therapeutic molecules into and through the skin. One approach is to use the nanoparticulate delivery system. Starting with liposomes and other vesicular systems, several other types of nanosized drug carriers have been developed such as solid lipid nanoparticles, nanostructured lipid carriers, polymer-based nanoparticles and magnetic nanoparticles for dermatological applications. This review article discusses how different particulate systems can interact and penetrate into the skin barrier. In this review, the effectiveness of nanoparticles, as well as possible mode of actions of nanoparticles, is presented. In addition to nanoparticles, cell-penetrating peptide (CPP)-mediated drug delivery into the skin and the possible mechanism of CPP-derived delivery into the skin is discussed. Lastly, the effectiveness and possible mechanism of CPP-modified nanocarriers into the skin are addressed.

Inhibition of HSP27 phosphorylation by a cell-permeant MAPKAP Kinase 2 inhibitor

Heat shock protein 27 (HSP27) has been implicated in many intracellular signaling processes. Since the phosphorylation of HSP27 can modulate its activity, the ability to inhibit phosphorylation of HSP27 might have clinical relevance especially with regard to the treatment of fibrosis. We have developed a cell-permeant peptide inhibitor of MAPKAP Kinase 2 (MK2), an enzyme that phosphorylates HSP27, by combining a previously described peptide substrate of MK2 with a cell penetrating peptide. This novel MK2 inhibitor (MK2i) reduced HSP27 phosphorylation by MK2 in vitro. At 10 microM, MK2i inhibited TGF-beta1-induced HSP27 phosphorylation in serum-starved human keloid fibroblasts. In addition, 10 microM MK2i decreased TGF-beta1-induced expression of connective tissue growth factor and collagen type I within serum-starved keloid fibroblasts. Thus, MK2i represents a potential therapeutic for the treatment of fibrotic disorders.