Receptor-selective retinoids for psoriasis: focus on tazarotene

From Traditional Medicine to Advanced Therapeutics: The Renaissance of Phyto-nano Interventions in Psoriasis

Psoriasis is an autoimmune systemic chronic inflammatory disease that exhibits characteristic detrimental effects on the skin, often leading to infections or comorbid conditions. The multifaceted nature of psoriasis has made it very challenging to treat, especially with current chemotherapy options. Therefore, it is essential to consider phytoconstituents as novel alternatives. However, despite demonstrating higher anti-inflammatory, anti-psoriasis, and immunomodulatory potential, their clinical usage is hindered due to their poor physicochemical properties. To address these drawbacks, nanoparticulate drug delivery systems have been developed, helping to achieve better permeation of phytoconstituents through topical administration. This has breathed new life into traditional systems of medicine, particularly in the context of treating psoriasis. In this current review, we present a detailed, comprehensive, and up-to-date analysis of the literature, which will contribute to affirming the clinical role of phyto-nano interventions against psoriasis.

Drug screening identifies tazarotene and bexarotene as therapeutic agents in multiple sulfatase deficiency

Multiple sulfatase deficiency (MSD, MIM #272200) results from pathogenic variants in the SUMF1 gene that impair proper function of the formylglycine-generating enzyme (FGE). FGE is essential for the posttranslational activation of cellular sulfatases. MSD patients display reduced or absent sulfatase activities and, as a result, clinical signs of single sulfatase disorders in a unique combination. Up to date therapeutic options for MSD are limited and mostly palliative. We performed a screen of FDA-approved drugs using immortalized MSD patient fibroblasts. Recovery of arylsulfatase A activity served as the primary readout. Subsequent analysis confirmed that treatment of primary MSD fibroblasts with tazarotene and bexarotene, two retinoids, led to a correction of MSD pathophysiology. Upon treatment, sulfatase activities increased in a dose- and time-dependent manner, reduced glycosaminoglycan content decreased and lysosomal position and size normalized. Treatment of MSD patient derived induced pluripotent stem cells (iPSC) differentiated into neuronal progenitor cells (NPC) resulted in a positive treatment response. Tazarotene and bexarotene act to ultimately increase the stability of FGE variants. The results lay the basis for future research on the development of a first therapeutic option for MSD patients.

S2k guidelines for the treatment of psoriasis in children and adolescents - Short version part 1

The present guidelines are aimed at residents and board-certified physicians in the fields of dermatology, pediatrics, pediatric dermatology and pediatric rheumatology as well as policymakers and insurance funds. They were developed by dermatologists and pediatric dermatologists in collaboration with pediatric rheumatologists using a formal consensus process (S2k). The guidelines highlight topics such as disease severity, quality of life, treatment goals as well as problems associated with off-label drug therapy in children. Trigger factors and diagnostic aspects are discussed. The primary focus is on the various topical, systemic and UV-based treatment options available and includes recommendations for use and treatment algorithms. Other aspects addressed herein include vaccinations in children and adolescents with psoriasis as well as various disease subtypes such as guttate psoriasis, diaper psoriasis, pustular psoriasis and psoriatic arthritis. Finally, we also provide recommendations for imaging studies and the diagnostic workup to rule out tuberculosis prior to initiating systemic treatment. Note: This article constitutes part 1 of the Sk2 guidelines for the treatment of psoriasis in children and adolescents. Part 2 will be published in the next issue. It contains chapters on UV therapy, systemic treatment, tonsillectomy and antibiotics, vaccinations, guttate psoriasis, psoriatic arthritis, complementary medicine, as well as imaging studies and diagnostic workup to rule out tuberculosis prior to systemic treatment.

Pharmacokinetics of tazarotene and acitretin in psoriasis

INTRODUCTION

Psoriasis is a prevalent cutaneous condition with severe physical and psychological manifestations. Since the advent of biologics, clinical outcomes in psoriasis have improved. However, retinoids are useful in the correct clinical context. Tazarotene and acitretin are currently the only US Food and Drug Administration approved retinoids for treatment of psoriasis. Both topical tazarotene and oral acitretin act on retinoic acid receptors and retinoid-X-receptors, resulting in altered gene expression of inflammatory cytokines and inhibition of keratinocyte proliferation. Areas covered: This article provides an in-depth pharmacologic and clinical review on the use of tazarotene and acitretin in psoriasis. The PubMed database was searched using combinations of keywords: acitretin, bioavailability, dosing, efficacy, etretinate, interactions, mechanism, pharmacodynamics, pharmacokinetics, pharmacogenetics, psoriasis, safety, tazarotene, tolerability, and toxicity. Expert opinion: Tazarotene and acitretin are effective treatments for psoriasis. Benefits include lack of immunosuppression and success treating inflammatory psoriasis. When combined with other topical and systemic agents, both retinoids improve clinical efficacy while lowering the treatment threshold. However, topical adherence and bothersome side effects can limit retinoid use. Acitretin and tazarotene both improve outcomes through a unique mechanism that especially benefits subsets of patients, despite side effects and limitations.

The Retinoid Agonist Tazarotene Promotes Angiogenesis and Wound Healing

Therapeutic angiogenesis is a major goal of regenerative medicine, but no clinically approved small molecule exists that enhances new blood vessel formation. Here we show, using a phenotype-driven high-content imaging screen of an annotated chemical library of 1,280 bioactive small molecules, that the retinoid agonist Tazarotene, enhances in vitro angiogenesis, promoting branching morphogenesis, and tubule remodeling. The proangiogenic phenotype is mediated by retinoic acid receptor but not retinoic X receptor activation, and is characterized by secretion of the proangiogenic factors hepatocyte growth factor, vascular endothelial growth factor, plasminogen activator, urokinase and placental growth factor, and reduced secretion of the antiangiogenic factor pentraxin-3 from adjacent fibroblasts. In vivo, Tazarotene enhanced the growth of mature and functional microvessels in Matrigel implants and wound healing models, and increased blood flow. Notably, in ear punch wound healing model, Tazarotene promoted tissue repair characterized by rapid ear punch closure with normal-appearing skin containing new hair follicles, and maturing collagen fibers. Our study suggests that Tazarotene, an FDA-approved small molecule, could be potentially exploited for therapeutic applications in neovascularization and wound healing.

Nail psoriasis: a review

Nail psoriasis is common, occurring in up to half of patients with psoriasis and in 90% of patients with psoriatic arthritis. Left untreated, it may progress to debilitating nail disease, which leads to significant functional impairment. The most common clinical signs of nail psoriasis are nail plate pitting and onycholysis. Other classical signs include oil drop discoloration, subungual hyperkeratosis, and splinter hemorrhages. The modified Nail Psoriasis Severity Index (mNAPSI) can be used to grade the severity of nail psoriasis, while the Nail Psoriasis Quality of Life Scale (NPQ10) is a questionnaire that evaluates the impact of nail psoriasis on the patient's functional status and quality of life. Treatment of nail psoriasis should be individualized according to the patient's preferences, severity of nail changes, and presence of skin and/or joint involvement. Both topical and intralesional therapies are safe and effective treatment modalities for nail disease, but are limited by poor adherence and pain, respectively. Systemic therapy such as oral retinoids may be considered for widespread nail disease causing significant morbidity. Among biologic agents, tumor necrosis factor-α inhibitors and T-cell-targeted therapies such as ustekinumab may be useful for refractory severe nail psoriasis.

Identifying disease-specific genes based on their topological significance in protein networks

BACKGROUND

The identification of key target nodes within complex molecular networks remains a common objective in scientific research. The results of pathway analyses are usually sets of fairly complex networks or functional processes that are deemed relevant to the condition represented by the molecular profile. To be useful in a research or clinical laboratory, the results need to be translated to the level of testable hypotheses about individual genes and proteins within the condition of interest.

RESULTS

In this paper we describe novel computational methodology capable of predicting key regulatory genes and proteins in disease- and condition-specific biological networks. The algorithm builds shortest path network connecting condition-specific genes (e.g. differentially expressed genes) using global database of protein interactions from MetaCore. We evaluate the number of all paths traversing each node in the shortest path network in relation to the total number of paths going via the same node in the global network. Using these numbers and the relative size of the initial data set, we determine the statistical significance of the network connectivity provided through each node. We applied this method to gene expression data from psoriasis patients and identified many confirmed biological targets of psoriasis and suggested several new targets. Using predicted regulatory nodes we were able to reconstruct disease pathways that are in excellent agreement with the current knowledge on the pathogenesis of psoriasis.

CONCLUSION

The systematic and automated approach described in this paper is readily applicable to uncovering high-quality therapeutic targets, and holds great promise for developing network-based combinational treatment strategies for a wide range of diseases.

Identification of a novel retinoid by small molecule screening with zebrafish embryos

Small molecules have played an important role in delineating molecular pathways involved in embryonic development and disease pathology. The need for novel small molecule modulators of biological processes has driven a number of targeted screens on large diverse libraries. However, due to the specific focus of such screens, the majority of the bioactive potential of these libraries remains unharnessed. In order to identify a higher proportion of compounds with interesting biological activities, we screened a diverse synthetic library for compounds that perturb the development of any of the multiple organs in zebrafish embryos. We identified small molecules that affect the development of a variety of structures such as heart, vasculature, brain, and body-axis. We utilized the previously known role of retinoic acid in anterior-posterior (A-P) patterning to identify the target of DTAB, a compound that caused A-P axis shortening in the zebrafish embryo. We show that DTAB is a retinoid with selective activity towards retinoic acid receptors gamma and beta. Thus, conducting zebrafish developmental screens using small molecules will not only enable the identification of compounds with diverse biological activities in a large chemical library but may also facilitate the identification of the target pathways of these biologically active molecules.