Downmodulation of key inflammatory cell markers with a topical Janus kinase 1/2 inhibitor

Mass Spectrometry-Based Proteomics Analysis Unveils PTPRS Inhibits Proliferation and Inflammatory Response of Keratinocytes in Psoriasis

In this study, we used data-independent acquisition-mass spectrometry (DIA-MS) to analyze the serum proteome in psoriasis vulgaris (PsO). The serum proteomes of seven healthy controls and eight patients with PsO were analyzed using DIA-MS. Weighted gene co-expression network analysis was used to identify differentially expressed proteins (DEPs) that were closely related to PsO. Hub proteins of PsO were also identified. The Proteomics Drug Atlas 2023 was used to predict candidate hub protein drugs. To confirm the expression of the candidate factor, protein tyrosine phosphatase receptor S (PTPRS), in psoriatic lesions and the psoriatic keratinocyte model, immunohistochemical staining, quantitative real-time polymerase chain reaction, and western blotting were performed. A total of 129 DEPs were found to be closely related to PsO. The hub proteins for PsO were PVRL1, FGFR1, PTPRS, CDH2, CDH1, MCAM, and THY1. Five candidate hub protein drugs were identified: encorafenib, leupeptin, fedratinib, UNC 0631, and SCH 530348. PTPRS was identified as a common pharmacological target for these five drugs. PTPRS knockdown in keratinocytes promoted the proliferation and expression of IL-1α, IL-1β, IL-23A, TNF-α, MMP9, CXCL8, and S100A9. PTPRS expression was decreased in PsO, and PTPRS negatively regulated PsO. PTPRS may be involved in PsO pathogenesis through the inhibition of keratinocyte proliferation and inflammatory responses and is a potential treatment target for PsO.

Inhibition of the JAK-STAT Pathway in the Treatment of Psoriasis: A Review of the Literature

Psoriasis is a highly prevalent dermatological disease associated with an increased systemic inflammatory response. In addition, joint involvement is also present in around 20% of patients. Therefore, treatment modalities used in this condition should be simultaneously effective at improving skin manifestations, reducing inflammation, and addressing psoriatic arthritis when present. Twenty years ago, the introduction of biologic treatments for psoriasis was a turning point in the management of this condition, offering an effective and reasonably safe option for patients whose disease could not be adequately controlled with conventional therapies. At the moment, Janus Kinase inhibitors (JAKis) are a new class of promising molecules in the management of psoriasis. They are orally administered and can show benefits in patients who failed biologic therapy. We conducted a scoping review in order to identify randomized-controlled trials that investigated different JAKis in patients with plaque psoriasis and psoriatic arthritis, with an emphasis on molecules that have been approved by the European Medicines Agency and the Food and Drug Administration. The added value of this study is that it collected information about JAKis approved for two different indications, plaque psoriasis and psoriatic arthritis, in order to provide an integrated understanding of the range of effects that JAKis have on the whole spectrum of psoriasis manifestations.

Application of JAK inhibitors in paradoxical reaction through immune-related dermatoses

Biologics play a positive and effective role in the treatment of immune-related dermatoses. However, many other immune-related diseases have also manifested along with biologics treatment. Paradoxical reaction through immune-related dermatoses refer to the new onset or exacerbation of other immune-mediated dermatoses (mainly psoriasis and atopic dermatitis) after biologics treatment of inflammatory dermatoses (mainly psoriasis and atopic dermatitis), such as new atopic dermatitis (AD) in psoriasis (PsO) treatment and new PsO in AD treatment. A common genetic background and Inflammatory pathway are possible pathogenesis. Faced with paradoxical reactions, the choice of therapy needs to be directed toward therapies effective for both diseases, such as Janus kinase (JAK) inhibitors. The Janus kinase and signal transducer and activator of transcription (JAK-STAT) pathway plays an important role in the inflammatory pathway, and has been widely used in the treatment of AD and PsO in recent years. This article focuses on JAK inhibitors such as tofacitinib, baricitinib, ruxolitinib, Abrocitinib, upadacitinib, and deucravacitinib, to explore the possible application in treatment of paradoxical reactions. Common side effects, baseline risk factors and safety use of JAK inhibitors were discussed.

New and Emerging Oral/Topical Small-Molecule Treatments for Psoriasis

The introduction of biologic therapies has led to dramatic improvements in the management of moderate-to-severe psoriasis. Even though the efficacy and safety of the newer biologic agents are difficult to match, oral administration is considered an important advantage by many patients. Current research is focused on the development of oral therapies with improved efficacy and safety compared with available alternatives, as exemplified by deucravacitinib, the first oral allosteric Tyk2 inhibitor approved for the treatment of moderate to severe psoriasis in adults. Recent advances in our knowledge of psoriasis pathogenesis have also led to the development of targeted topical molecules, mostly focused on intracellular signaling pathways such as AhR, PDE-4, and Jak-STAT. Tapinarof (an AhR modulator) and roflumilast (a PDE-4 inhibitor) have exhibited favorable efficacy and safety outcomes and have been approved by the FDA for the topical treatment of plaque psoriasis. This revision focuses on the most recent oral and topical therapies available for psoriasis, especially those that are currently under evaluation and development for the treatment of psoriasis.

Selectivity, efficacy and safety of JAKinibs: new evidence for a still evolving story

Fundamental insight gained over the last decades led to the discovery of cytokines as pivotal drivers of inflammatory diseases such as rheumatoid arthritis, psoriasis/psoriasis arthritis, inflammatory bowel diseases, atopic dermatitis and spondylarthritis. A deeper understanding of the pro-inflammatory and anti-inflammatory effects of various cytokines has prompted new cytokine-targeting therapies, which revolutionised the treatment options in the last years for patients with inflammatory disorders. Disease-associated immune responses typically involve a complex interplay of multiple cytokines. Therefore, blockade of one single cytokine does not necessarily lead to a persistent remission in all patients with inflammatory disorders and fostered new therapeutic strategies targeting intracellular pathways shared by multiple cytokines. By inhibiting JAK-STAT signalling pathways common to families of cytokines, JAK-inhibitors (JAKinibs) have created a new paradigm for the treatment of inflammatory diseases. Multiple agents have been approved for various disorders and more are being investigated for several new indications. Second-generation selective JAKinibs have been devised with the aim to achieve an increased selectivity and a possible reduced risk of side effects. In the current review, we will summarise the current body of evidence of pan versus selective JAKinibs and the most recent insights on new side effects and indications, including COVID-19.

Long-Term Safety Profile and Off-Label Use of JAK Inhibitors in Dermatological Disorders

JAK inhibitors target specific inflammatory cytokines involved in various inflammatory diseases. Four molecules have been approved for dermatological use: upadacitinib, baricitinib, abrocitinib and topical ruxolitinib. Off-label prescriptions for other dermatological conditions have been reported. We conducted a narrative review of the literature to assess the long-term safety profile of currently approved JAK inhibitors in dermatology, and their off-label use in skin disorders. We performed literature searches with PubMed and Google Scholar from January 2000 to January 2023, using the keywords "Janus kinase inhibitors", "JAK inhibitors","off-label", "dermatology", "safety", "adverse events", "ruxolitinib", "upadacitinib","abrocitinib" and "baricitinib". Our search yielded a total of 37 dermatological disorders with studies supporting the use of these JAK inhibitors. Preliminary studies indicate that JAK inhibitors generally have a favorable safety profile and can be considered as an option in many dermatological disorders.

Long-Term Safety Profile and Off-Label Use of JAK Inhibitors in Dermatological Disorders

JAK inhibitors target specific inflammatory cytokines involved in various inflammatory diseases. Four molecules have been approved for dermatological use: upadacitinib, baricitinib, abrocitinib and topical ruxolitinib. Off-label prescriptions for other dermatological conditions have been reported. We conducted a narrative review of the literature to assess the long-term safety profile of currently approved JAK inhibitors in dermatology, and their off-label use in skin disorders. We performed literature searches with Pubmed and Google Scholar from January 2000 to January 2023, using the keywords "Janus kinase inhibitors", "JAK inhibitors", "off-label", "dermatology", "safety", "adverse events", "ruxolitinib", "upadacitinib", "abrocitinib" and "baricitinib". Our search yielded a total of 37 dermatological disorders with studies supporting the use of these JAK inhibitors. Preliminary studies indicate that JAK inhibitors generally have a favorable safety profile and can be considered as an option in many dermatological disorders.

Emerging role of topical Janus kinase inhibitors in dermatological disorders: a review

Janus kinase (JAK) refers to a family of tyrosine kinases that are involved in the production of proinflammatory mediators in response to various extracellular signals. The JAK-signal transducer and activator of transcription (STAT) pathway is an appealing target in many inflammatory illnesses as this pathway modulates immune cell activation and T-cell-mediated inflammation in response to several cytokines. The practical considerations of prescription for topical and oral JAK inhibitors (JAKis) in atopic dermatitis, vitiligo and psoriasis have been covered in prior publications. Currently, the US Food and Drug Administration has approved the topical JAKi ruxolitinib for atopic dermatitis and nonsegmental vitiligo. None of the remaining first- or second-generation topical JAKis have been approved for topical application in any dermatological indications so far. For this review, the PubMed database was searched using 'topical' and 'JAK inhibitor' or 'Janus kinase inhibitor' or the names of individual drug molecules as the keyword in the title with no date limits. The description of topical JAKi usage in dermatology from the literature was evaluated in each abstract. The current review concentrates on emphasizing the rising use of topical JAKis in both approved and off-label dermatological applications for both old and novel conditions.

Efficacy and safety of topical brepocitinib cream for mild-to-moderate chronic plaque psoriasis: a phase IIb randomized double-blind vehicle-controlled parallel-group study

BACKGROUND

Plaque psoriasis (PsO) is an inflammatory skin disease driven, in part, by the activation of Janus kinase (JAK) signalling pathways.

OBJECTIVES

To assess the efficacy and safety of multiple doses of topical brepocitinib, a tyrosine kinase 2/JAK1 inhibitor, in participants with mild-to-moderate PsO.

METHODS

This phase IIb multicentre randomized double-blind study was conducted in two stages. In stage 1, participants received one of eight treatments for 12 weeks: brepocitinib 0.1% once daily, 0.3% once or twice daily, 1.0% once or twice daily, 3.0% once daily, or vehicle once or twice daily. In stage 2, participants received brepocitinib 3.0% twice daily or vehicle twice daily. The primary endpoint was the change from baseline in Psoriasis Area and Severity Index (PASI) score at week 12, analysed using analysis of covariance. The key secondary endpoint was the proportion of participants who achieved a Physician Global Assessment response [score of clear (0) or almost clear (1) and an improvement of ≥ 2 points from baseline] at week 12. Additional secondary endpoints included the difference vs. vehicle in change from baseline in PASI, using mixed-model repeated measures, and the change from baseline in Peak Pruritus Numerical Rating Scale at week 12. Safety was monitored.

RESULTS

Overall, 344 participants were randomized. Topical brepocitinib did not result in statistically significant changes compared with respective vehicle controls in the primary or key secondary efficacy endpoints for any dose group. At week 12, least squares mean change from baseline in PASI score ranged from -1.4 to -2.4 for the brepocitinib once-daily groups vs. -1.6 for vehicle once daily, and from -2.5 to -3.0 for the brepocitinib twice-daily groups vs. -2.2 for vehicle twice daily. From week 8, change from baseline in PASI score separated from vehicle in all brepocitinib twice daily groups. Brepocitinib was well tolerated, with adverse events (AEs) occurring at similar rates across groups. One participant in the brepocitinib 1.0% once-daily group developed a treatment-related AE of herpes zoster in the neck area.

CONCLUSIONS

Topical brepocitinib was well tolerated but did not result in statistically significant changes compared with vehicle when administered at the doses evaluated to treat signs and symptoms of mild-to-moderate PsO.

Perspective insights of small molecules, phytoconstituents and biologics in the management of psoriasis: A focus on targeting major inflammatory cytokine pathways

Psoriasis is an enduring, pruritic and papulosquamous skin ailment that poses a significant burden on public health. It is mainly characterized by hyperkeratosis, acanthosis, parakeratosis, scaly and erythematous plaques. Biomarkers like interleukin-17, interleukin-12 and -23 and tumor necrosis factor-α serve as key drivers of psoriatic pathogenesis. Triggered release of pro-inflammatory cytokines from various up-regulated pathways leads to psoriatic inflammation. Several target moieties like biologics, small molecules and herbal moieties play a fundamental role in the repression of pathogenesis of psoriasis. Biologics and small molecules engaged in the management of psoriasis have been emphasized in detail. An insight into nano-carrier interventions on herbal moieties and clinical aspects of psoriasis are also highlighted. This review emphasizes various pathological targets involved in psoriasis.

Itch and Janus Kinase Inhibitors

Itch is a common skin symptom, with complex aetiology and pathogenesis. It is mediated by 2 pathways, the histaminergic and non-histaminergic pathways. Chronic itch is understood to be processed by the latter and is difficult to treat with traditional pruritus therapies. The Janus kinase and signal transducer and activator of transcription pathway is a signalling mechanism that regulates gene expression through various cytokines. Janus kinase inhibitors, which have been tested and used for several autoimmune diseases, have also been shown to be effective for itch through clinical trials and case reports. Janus kinase inhibitors could be a good choice for pruritus in atopic dermatitis, psoriasis, and other diseases, such as prurigo nodularis and lichen planus, with rapid itch relief compared with conventional treatments. The most common adverse effects reported include nasopharyngitis, acne, and elevated blood creatine phosphokinase levels. Janus kinase inhibitors are currently prescribed with warnings about a potential increase in malignancies and cardiovascular diseases and usage in people of older ages. This review aims to provide knowledge about itch and the Janus kinase and signal transducer and activator of transcription pathway and to analyse the current evidence for itch relief by Janus kinase inhibitors.

Pathogenesis, multi-omics research, and clinical treatment of psoriasis

Psoriasis is a common inflammatory skin disease involving interactions between keratinocytes and immune cells that significantly affects the quality of life. It is characterized by hyperproliferation and abnormal differentiation of keratinocytes and excessive infiltration of immune cells in the dermis and epidermis. The immune mechanism underlying this disease has been elucidated in the past few years. Research shows that psoriasis is regulated by the complex interactions among immune cells, such as keratinocytes, dendritic cells, T lymphocytes, neutrophils, macrophages, natural killer cells, mast cells, and other immune cells. An increasing number of signaling pathways have been found to be involved in the pathogenesis of psoriasis, which has prompted the search for new treatment targets. In the past decades, studies on the pathogenesis of psoriasis have focused on the development of targeted and highly effective therapies. In this review, we have discussed the relationship between various types of immune cells and psoriasis and summarized the major signaling pathways involved in the pathogenesis of psoriasis, including the PI3K/AKT/mTOR, JAK-STAT, JNK, and WNT pathways. In addition, we have discussed the results of the latest omics research on psoriasis and the epigenetics of the disease, which provide insights regarding its pathogenesis and therapeutic prospects; we have also summarized its treatment strategies and observations of clinical trials. In this paper, the various aspects of psoriasis are described in detail, and the limitations of the current treatment methods are emphasized. It is necessary to improve and innovate treatment methods from the molecular level of pathogenesis, and further provide new ideas for the treatment and research of psoriasis.

New Topical Therapies for Psoriasis

Psoriasis is a chronic immune-mediated skin disease with a significant impact on patients' quality of life. Mild-to-moderate forms of the disease usually require long-term topical treatment, but prolonged use of corticosteroids and vitamin D analogues is limited by adverse effects. With further understanding of psoriasis pathogenesis, new molecules are emerging aiming to fulfil these clinical needs. Tapinarof, an aryl hydrocarbon receptor modulator, has completed a phase III study and demonstrated good efficacy results, even in long treatment courses, with a favourable safety profile. It additionally appears to have a promising remitting effect as patients presented with an average relapsing time of over 3 months. Roflumilast, a phosphodiesterase type 4 inhibitor, also underwent a phase III study with significant lesion improvement and notable pruritus management, and with no reported side effects. Roflumilast was evaluated as an option for intertriginous areas with good outcomes in a small sample, but larger trials are required. The Janus kinase-signal transducer and activator of transcription pathway has been targeted in recent clinical investigations with promising options, currently with brepocitinib pending phase IIb results. Ongoing preclinical studies involving interleukin-2 inhibition, RNA modulators and amygdalin analogues may lead to forthcoming clinical trials. New topical drugs are successfully emerging and future research comparing them to classical options will dictate their clinical role in the treatment of psoriasis.

Repurposing approved therapeutics for new indication: Addressing unmet needs in psoriasis treatment

Psoriasis is a chronic inflammatory autoimmune condition manifested by the hyperproliferation of keratinocytes with buildup of inflammatory red patches and scales on skin surfaces. The available treatment options for the management of psoriasis have various drawbacks, and the clinical need for effective therapeutics for this disease remain unmet; therefore, the approaches of drug repurposing or drug repositioning could potentially be used for treating indications of psoriasis. The undiscovered potential of drug repurposing or repositioning compensates for the limitations and hurdles in drug discovery and drug development processes. Drugs initially approved for other indications, including anticancer, antidiabetic, antihypertensive, and anti-arthritic activities, are being investigated for their potential in psoriasis management as a new therapeutic indication by using repurposing strategies. This article envisages the potential of various therapeutics for the management of psoriasis.

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Psoriasis is an autoimmune inflammatory skin disorder with complex physiology.

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Conventional treatments for psoriasis cause severe adverse effects; therefore an unmet need remains for safer and more effective therapies for psoriasis.

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Various drugs that effectively decrease the inflammation and proliferation of skin cells can be repurposed for the management of psoriasis.

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Repurposed drugs provide various incentives to the pharmaceutical industry.

The involvement of JAK/STAT signaling pathway in the treatment of Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder in which inflammation and oxidative stress play key etiopathological role. The pathology of PD brain is characterized by inclusions of aggregated α-synuclein (α-SYN) in the cytoplasmic region of neurons. Clinical evidence suggests that stimulation of pro-inflammatory cytokines leads to neuroinflammation in the affected brain regions. Upon neuroinflammation, the Janus Kinase/Signal Transducers and Activators of Transcription (JAK/STAT) signaling pathway, and other transcription factors such as nuclear factor κB (NF-κB), NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3), mammalian target of rapamycin (mTOR), and toll-like receptors (TLRs) are upregulated and induce the microglial activation, contributing to PD via dopaminergic neuron autophagy. Aberrant activation or phosphorylation of the components of JAK/STAT signaling pathway has been implicated in increased transcription of the inflammation-associated genes and many neurodegenerative disorders such as PD. Interferon gamma (IFN-γ), and interleukine (IL)-6 are two of the most potent activators of the JAK/STAT pathway, and it was shown to be elevated in PD. Stimulation of microglial cell with aggregated α-SYN results in production of nitric oxide (NO), tumor necrosis factor (TNF)-α, and IL-1β in PD. Dysregulation of the JAK/STAT in PD and its involvement in various inflammatory pathways make it a promising PD therapy approach. So far, a variety of synthetic or natural small-molecule JAK inhibitors (Jakinibs) have been found promising in managing a spectrum of ailments, many of which are in preclinical research or clinical trials. Herein, we provided a perspective on the function of the JAK/STAT signaling pathway in PD progression and gathered data that describe the rationale evidence on the potential application of Jakinibs to improve neuroinflammation in PD.

Role of Janus Kinase Inhibitors in Therapy of Psoriasis

Janus kinases inhibitors are molecules that target Janus kinases-signal transducers and activators of transcription (JAK/STAT). They inhibit this intracellular signal pathway, blocking the gene transcription of crucial proinflammatory cytokines that play a central role in the pathogenesis of many inflammatory and autoimmune diseases, including psoriasis. This process reduces psoriatic inflammation. The JAK inhibitors are divided into two generations. The first generation of JAK inhibitors blocks two or more different Janus kinases. The second generation is more specified and blocks only one type of Janus kinase and has less side effects than the first generation. Tofacitinib, ruxolitinib and baricitinib belong to first generation JAK inhibitors and decernotinib and filgotinib belong to second group. This narrative review summarizes the role of Janus kinase inhibitors in the therapy of psoriasis. Oral JAK inhibitors show promise for efficacy and safety in the treatment of psoriasis. Studies to date do not indicate that JAK inhibitors are superior to recent biologic drugs in terms of efficacy. However, JAK inhibitors, due to their lack of increased incidence of side effects compared to other biologic drugs, can be included in the psoriasis treatment algorithm because they are orally taken. Nevertheless, further studies are needed to evaluate long-term treatment effects with these drugs.

Off-label Studies on the Use of Ruxolitinib in Dermatology

PURPOSE

Ruxolitinib (Jakafi) is a Janus kinase 1 and 2 small molecule inhibitor that the Food and Drug Administration approved for myelofibrosis and polycythemia vera. It has been expanded to off-label treatment for a variety of dermatologic conditions, with several clinical trials ongoing. A review of available studies and cases of off-label uses was performed to guide clinicians seeking evidence on the efficacy of this Janus kinase inhibitor for dermatologic disorders.

MATERIALS AND METHODS

PubMed/MEDLINE, EMBASE, Scopus, and ClinicalTrials.gov databases were searched with the term "ruxolitinib," and results were manually reviewed to identify published data on off-label uses of ruxolitinib. Studies included are structured by quality of evidence available.

RESULTS

Ruxolitinib may have utility in the treatment of atopic dermatitis, psoriasis, and vitiligo, with data from open-label and randomized trials supporting efficacy of topical formulations. Evidence of utility for alopecia areata is mixed and differs depending on topical versus oral form. Evidence for numerous other conditions is available through case reports and case series.

CONCLUSIONS

There is growing evidence supporting potential off-label use of oral and topical ruxolitinib for a wide range of skin conditions. There are several ongoing investigations of ruxolitinib use in dermatology that will undoubtedly better define its efficacy and appropriate use in dermatology.

The Effect of JAK Inhibitor on the Survival, Anagen Re-Entry, and Hair Follicle Immune Privilege Restoration in Human Dermal Papilla Cells

Topical or systemic administration of JAK inhibitors has been shown to be a new treatment modality for severe alopecia areata (AA). Some patients show a good response to JAK inhibitors, but frequently relapse after cessation of the treatment. There have been no guidelines about the indications and use of JAK inhibitors in treating AA. The basic pathomechanism of AA and the relevant role of JAK inhibitors should support how to efficiently use JAK inhibitors. We sought to investigate the effect of JAK1/2 inhibitor on an in vitro model of AA and to examine the possible mechanisms. We used interferon gamma-pretreated human dermal papilla cells (hDPCs) as an in vitro model of AA. Ruxolitinib was administered to the hDPCs, and cell viability was assessed. The change of expression of the Wnt/β-catenin pathway, molecules related to the JAK-STAT pathway, and growth factors in ruxolitinib-treated hDPCs was also examined by reverse transcription PCR and Western blot assay. We examined immune-privilege-related molecules by immunohistochemistry in hair-follicle culture models. Ruxolitinib did not affect the cell viability of the hDPCs. Ruxolitinib activated several molecules in the Wnt/β-catenin signaling pathway, including Lef1 and β-catenin, and suppressed the transcription of DKK1 in hDPCs, but not its translation. Ruxolitinib reverted IFN-γ-induced expression of caspase-1, IL-1β, IL-15, and IL-18, and stimulated several growth factors, such as FGF7. Ruxolitinib suppressed the phosphorylation of JAK1, JAK2 and JAK3, and STAT1 and 3 compared to IFN-γ pretreated hDPCs. Ruxolitinib pretreatment showed a protective effect on IFN-γ-induced expression of MHC-class II molecules in cultured hair follicles. In conclusion, ruxolitinib modulated and reverted the interferon-induced inflammatory changes by blocking the JAK-STAT pathway in hDPCs under an AA-like environment. Ruxolitinib directly stimulated anagen-re-entry signals in hDPCs by affecting the Wnt/β-catenin pathway and promoting growth factors in hDPCs. Ruxolitinib treatment prevented IFN-γ-induced collapse of hair-follicle immune privilege.

Off-label studies on ruxolitinib in dermatology: a review

Ruxolitinib is a Janus kinase (JAK) inhibitor that is FDA-approved for the treatment of myelofibrosis, polycythemia vera, and acute graft-versus-host disease. Its use in treating various dermatologic diseases has been a topic of growing interest due to its favorable safety profile and targeted inhibition of several cytokines that perpetuate inflammatory skin conditions. The PubMed/MEDLINE and ClinicalTrials.gov databases were searched for literature on off-label uses of ruxolitinib in dermatology and ongoing trials studying its safety and efficacy. There is randomized controlled trial (RCT) evidence for the successful use of ruxolitinib in treating alopecia, atopic dermatitis, and psoriasis, with ongoing RCTs for its use in vitiligo. Smaller studies have confirmed the success of ruxolitinib in treating conditions such as dermatomyositis and hypereosinophilic syndrome, among others. No serious adverse effects were reported with the use of ruxolitinib in dermatology, but further research is needed to determine its efficacy, delivery route, and optimal dosing for treating dermatologic conditions.

Systemic Treatment of Psoriasis with JAK Inhibitors: A Review

Psoriasis is a prevalent chronic inflammatory disease. The inflammatory response is driven by T cells and mediated by multiple cytokines such as tumor necrosis factor and the interleukins IL-17 and IL-23. Moderate-to-severe psoriasis is treated systemically, using either biologics or conventional treatments with small-molecule drugs. The newer biologics are very effective and well tolerated, but not all patients respond to treatment with biologics, so there is a need for new treatment options for psoriasis. Janus kinase (JAK) inhibitors are a new drug class that may be of use in this respect. These inhibitors are already on the market for rheumatoid arthritis, psoriatic arthritis, and ulcerative colitis. They block the intracellular signal pathway mediated by JAK and signal transducer and activator of transcription (STAT) proteins, thereby inhibiting gene transcription of proinflammatory cytokines. JAK inhibitors are currently being tested as potential treatments for psoriasis. They have shown clinical efficacy as measured by the Psoriasis Area and Severity Index 75 response in both phase 2 and 3 trials, and appear to be well tolerated overall. This review provides an overview of the mechanisms underlying the actions of JAK inhibitors in psoriasis, together with the results of clinical trials testing their efficacies when used to treat the disease.

JAK-inhibitors. New players in the field of immune-mediated diseases, beyond rheumatoid arthritis

Janus kinase (JAK)/signal transducers and activators of transcription (STATs) are a group of molecules associated with one of the major pathways through which many cytokines exert and integrate their function, and as such they are increasingly recognized as playing critical role in the pathogenesis subserving various immune-mediated diseases, including RA, PsA, SpAs, IBD, skin disorders (e.g. alopecia areata, atopic dermatitis), single-gene disorders like interferonopathies, and others. JAKs are the key initiating players of the JAK/STAT pathway. Upon binding of their respective effector molecules (cytokines, IFNs, growth factors and others) to type I and type II receptors, JAKs are activated, and through phosphorylation of themselves and of other molecules (including STATs), they mediate signal transduction to the nucleus. A class of drugs—called JAK inhibitors or JAKinibs—that block one or more JAKs has been developed in the last decade, and now numbers >20 members. Although, so far, JAK inhibitors have been marketed only for RA and PsA, these drugs have been tested in phase 2 and phase 3 clinical trials for other inflammatory conditions and beyond. In this review, we summarize the clinical data, including efficacy and safety, available for JAK inhibitors used in some immune-mediated conditions other than RA.

Targeting the Janus Kinase Family in Autoimmune Skin Diseases

Autoimmune skin diseases are characterized by significant local and systemic inflammation that is largely mediated by the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway. Advanced understanding of this pathway has led to the development of targeted inhibitors of Janus kinases (JAKinibs). As a class, JAK inhibitors effectively treat a multitude of hematologic and inflammatory diseases. Growing evidence suggests that JAK inhibitors are efficacious in atopic dermatitis, alopecia areata, psoriasis, and vitiligo. Additional evidence suggests that JAK inhibition might be broadly useful in dermatology, with early reports of efficacy in several other conditions. JAK inhibitors can be administered orally or used topically and represent a promising new class of medications. Here we review the evolving data on the role of the JAK-STAT pathway in inflammatory dermatoses and the potential therapeutic benefit of JAK-STAT antagonism.

Transdermal permeability of triamcinolone acetonide lipid nanoparticles

Background

Triamcinolone acetonide (TAA) is an effective and the most commonly used corticosteroid hormone for the treatment of hypertrophic scars (HSs). However, the clinically used dosage has poor tissue permeability and injection safety. By contrast, lipid nanoparticles (LNPs) have the advantage of high affinity for the skin.

Materials and methods

This article describes the preparation of TAA-LNPs using poly(lactic-co-glycolic acid) as a carrier material, which have good biocompatibility and biodegradability. Based on a systematic investigation of its physicochemical properties, a rabbit ear HSs model was established to evaluate the percutaneous permeability of TAA-LNPs in scar tissue in vitro as well as to assess its curative effect and skin irritation.

Results

The results showed that the TAA-LNPs formed uniform and round particles under fluoroscopy and had a complex structure in which a nanoparticle core was surrounded by multiple vesicles. The particles were 232.2±8.2 nm in size, and the complimentary potential was -42.16 mV. The encapsulation efficiency was 85.24%, which is greater than that of other common liposomes and nanoparticles. A test of in vitro scar tissue permeability showed that penetration into scar tissue was twofold and 40-fold higher for TAA-LNPs than for common liposome and commercial suspensions, respectively. The concentration of the absorbed drug effectively inhibited fibroblast proliferation, achieved a therapeutic effect in HSs, and did not stimulate intact or damaged skin.

Conclusion

The preparation of TAA into LNPs for transdermal administration can enhance transdermal permeation performance and the safety of this drug, which is beneficial for the treatment of HSs.

Comparative efficacy of topical oclacitinib 0.1% and tacrolimus 0.01% in canine keratoconjunctivitis sicca

OBJECTIVE

To assess the efficacy of 0.1% oclacitinib as a single agent, and in combination with tacrolimus 0.01%, for the control of ophthalmic signs of keratoconjunctivitis sicca (KCS) in dogs.

ANIMALS STUDIED

Thirty-two dogs (57 eyes) diagnosed with idiopathic KCS were included. Inclusion criteria were Schirmer Tear Test 1 (STT-1) values <15 mm/min and concurrent clinical signs such as ocular hyperemia and discharge.

PROCEDURES

The animals were submitted to a randomized, open-label, 5-week study and divided into 3 treatment groups treated with the following ophthalmic solutions: (a) 0.1% oclacitinib, (b) 0.1% oclacitinib +0.01% tacrolimus, and (c) 0.01% tacrolimus. Eye drops were instilled twice daily (12-hour intervals). At each follow-up examination, STT-1, clinical signs, and potential drug side effects were assessed.

RESULTS

Oclacitinib did not significantly improve STT-1 values or clinical scores. Tacrolimus alone and in combination with oclacitinib increased mean STT-1 values by 11.84 ± 5.2 and 12.46 ± 5.3 mm/min, respectively (P = 0.0001). Clinical scores of ocular discharge and hyperemia also improved significantly in both groups receiving treatment with tacrolimus (P < 0.05). However, addition of oclacitinib to tacrolimus provided no additional improvement over tacrolimus alone.

CONCLUSIONS

Topical 0.1% oclacitinib twice daily is not effective in controlling the ocular signs of KCS in dogs. 0.01% tacrolimus increased STT-1 values significantly and could potentially be used as a treatment for mild-to-moderate cases of KCS. Synergism between drugs did not occur, and therefore the use of oclacitinib is not justified in cases of canine KCS.

Selective JAKinibs: Prospects in Inflammatory and Autoimmune Diseases

Cytokines, many of which signal through the JAK-STAT (Janus kinase-Signal Transducers and Activators of Transcription) pathway, play a central role in the pathogenesis of inflammatory and autoimmune diseases. Currently three JAK inhibitors have been approved for clinical use in USA and/or Europe: tofacitinib for rheumatoid arthritis, psoriatic arthritis and ulcerative colitis, baricitinib for rheumatoid arthritis, and ruxolitinib for myeloproliferative neoplasms. The clinical JAK inhibitors target multiple JAKs at high potency and current research has focused on more selective JAK inhibitors, almost a dozen of which currently are being evaluated in clinical trials. In this narrative review, we summarize the status of the pan-JAK and selective JAK inhibitors approved or in clinical trials, and discuss the rationale for selective targeting of JAKs in inflammatory and autoimmune diseases.

Topical agents for the treatment of atopic dermatitis

INTRODUCTION

Atopic dermatitis (AD) is perhaps the most common inflammatory skin disorder worldwide, with an increasing incidence in developed countries. The mainstay treatment for patients with AD is topical therapies, which are used not only by the mild patients but also by the moderate-to-severe patients, in conjunction with systemic treatment. While topical steroids and calcineurin antagonists are widely used, these are associated with long-term cutaneous adverse effects (AEs) or a black box warning, preventing their chronic use. Areas covered: The aim of this review is to provide a comprehensive overview of new and upcoming topical therapies currently in development and undergoing clinical trials, as well as their safety and efficacy profiles, and discuss current topicals used in the management of AD. Expert opinion: AD is a heterogeneous disease with complex pathophysiology. Treatments available to date for AD provide disease control; however, patients struggle to find an optimized therapeutic regimen they may use long term and without severe effects. Novel therapies are currently under investigation, with the hope of shifting the paradigm of AD management from symptom control to disease eradication.

Phosphorylation of intracellular signalling molecules in peripheral blood cells from patients with psoriasis on originator or biosimilar infliximab

BACKGROUND

Psoriasis vulgaris is a chronic, inflammatory skin disease characterized by a dysregulated immune response and it is associated with substantial systemic comorbidities. Biological drugs such as tumour necrosis factor (TNF)-α inhibitors can ameliorate the disease but are expensive. Biosimilar drugs have the same amino-acid sequence as the originator, but differences in manufacturing can affect biological activity, efficacy and tolerability.

OBJECTIVES

To explore potential differences in intracellular phosphorylation of signalling molecules in peripheral blood cells from patients with psoriasis treated with the TNF-α inhibitor infliximab compared with healthy controls, and to investigate if the phosphorylation pattern was influenced by switching from the originator infliximab to the biosimilar CT-P13.

METHODS

By flow cytometry, we measured phosphorylation of nuclear factor kappa B, extracellular signal-regulated kinase 1/2, p38 mitogen-activated protein kinase and signal transducer and activator of transcription 3, before and after TNF-α stimulation in monocytes and T, B, natural killer and CD3⁺  CD56⁺ cells from 25 patients with psoriasis treated with infliximab and 19 healthy controls.

RESULTS

At inclusion, phosphorylation levels of peripheral blood mononuclear cells (PBMCs) were increased in patients with psoriasis compared with healthy controls, even though clinical remission had already been achieved. Phosphorylation levels declined in patients on both originator infliximab and biosimilar during continued treatment. No significant differences were detected between the two medications after 12 months.

CONCLUSIONS

Patients with psoriasis on infliximab have higher activation levels of PBMCs than do healthy controls, possibly reflecting systemic inflammation. Switching from the originator infliximab to biosimilar CT-P13 did not affect phosphorylation levels or clinical parameters, suggesting that CT-P13 is a noninferior treatment alternative to the originator infliximab.

JAK inhibition as a therapeutic strategy for immune and inflammatory diseases

This corrects the article DOI: 10.1038/nrd.2017.201.

Repression of interferon β-regulated cytokines by the JAK1/2 inhibitor ruxolitinib in inflammatory human macrophages

Ruxolitinib is a Janus kinase (JAK) 1/2 inhibitor, currently used in the treatment of myeloproliferative neoplasms. It exerts potent anti-inflammatory activity, but the involved molecular and cellular mechanisms remain poorly understood. In order to gain insights about this point, ruxolitinib effects towards expression of main inflammatory cytokines were studied in human macrophages, which constitute a key-cell type implicated in inflammation. Analysis of mRNA expression of cytokines (n=84) by PCR array indicated that, among those induced by the pro-inflammatory stimulus lipopolysaccharide (LPS) (n=44), 61.4% (n=27) were repressed by 5μM ruxolitinib. The major inflammatory cytokines, interleukin (IL) 6 and tumor necrosis factor α, were notably down-regulated by ruxolitinib at both the mRNA and protein level. Other repressed cytokines included IL27 and the chemokines CCL2, CXCL9, CXCL10 and CXCL11, but not IL1β. The interferon (IFN) β/JAK/signal transducer and activator of transcription (STAT) pathway, well-activated by LPS in human macrophages as demonstrated by increased secretion of IFNβ, STAT1 phosphorylation, and up-regulation of reference IFNβ-responsive genes, was concomitantly blocked by the JAK inhibitor. Most of cytokines targeted by ruxolitinib were shown to be regulated by IFNβ in a JAK-sensitive manner. In addition, counteracting the IFNβ/JAK/STAT cascade using a blocking monoclonal antibody directed against IFNβ receptor resulted in a similar profile of cytokine repression to that observed in response to the JAK inhibitor. Overall, these data provide evidence for ruxolitinib-mediated repression of inflammatory cytokines in human macrophages through inhibition of the LPS/IFNβ/JAK/STAT signalling pathway, which probably contributes to the anti-inflammatory effects of the JAK inhibitor.

JAK inhibition as a therapeutic strategy for immune and inflammatory diseases

The discovery of cytokines as key drivers of immune-mediated diseases has spurred efforts to target their associated signalling pathways. Janus kinases (JAKs) are essential signalling mediators downstream of many pro-inflammatory cytokines, and small-molecule inhibitors of JAKs (jakinibs) have gained traction as safe and efficacious options for the treatment of inflammation-driven pathologies such as rheumatoid arthritis, psoriasis and inflammatory bowel disease. Building on the clinical success of first-generation jakinibs, second-generation compounds that claim to be more selective are currently undergoing development and proceeding to clinical trials. However, important questions remain about the advantages and limitations of improved JAK selectivity, optimal routes and dosing regimens and how best to identify patients who will benefit from jakinibs. This Review discusses the biology of jakinibs from a translational perspective, focusing on recent insights from clinical trials, the development of novel agents and the use of jakinibs in a spectrum of immune and inflammatory diseases.

Anthralin modulates the expression pattern of cytokeratins and antimicrobial peptides by psoriatic keratinocytes

BACKGROUND

Psoriasis is an inflammatory skin disease with aberrant keratinocyte proliferation, presumably as a result of immune cell activation. Th17 cytokines like IL-17A and IL-22 are critically implicated in epidermal thickening, altered keratinocyte differentiation and production of innate factors such as antimicrobial peptides. Psoriasis treatment options include modern targeted therapies using anti-cytokine antibodies and traditional non-targeted treatments like anthralin (dithranol). While the mode of action of anti-cytokine antibodies is defined, the effects of topical anthralin on psoriatic skin are not fully understood.

OBJECTIVE

This study aims to unravel the direct effects of anthralin on keratinocyte proliferation, differentiation and production of psoriasis-associated factors.

METHODS

We tested the effects of anthralin on cell proliferation, cytokeratin expression and changes in the expression of antimicrobial peptides using primary keratinocytes and 3D psoriasis tissue models with and without stimulation of the psoriasis-promoting cytokines IL-17A and IL-22. Moreover, we compared the findings derived from monolayer and multilayer cultures to data derived from lesional skin of patients with psoriasis before and under treatment with anthralin.

RESULTS

Our study shows that anthralin directly induces cell apoptosis in vitro in monolayer cultures but not in 3D psoriasis tissue models treated with IL-17A and IL-22. Yet, keratinocyte proliferation as determined by Ki-67 staining is impaired by anthralin in vivo. In lesional skin but not in 3D psoriasis tissue models anthralin rapidly normalizes cytokeratin (CK)16 expression. Furthermore, anthralin directly inhibits DEFB4 expression in vitro and in vivo, while other antimicrobial peptides and cytokines studied like IL-6 and IL-8 are regulated differently in vitro and in vivo.

CONCLUSIONS

Our results show that anthralin directly regulates DEFB4A expression. However, its beneficial effects on psoriasis cannot be explained by direct effects on keratinocyte differentiation or cytokine expression.

JAK inhibitors in dermatology: The promise of a new drug class

New molecularly targeted therapeutics are changing dermatologic therapy. Janus kinase-signal transducer and activator of transcription (JAK-STAT) is an intracellular signaling pathway upon which many different proinflammatory signaling pathways converge. Numerous inflammatory dermatoses are driven by soluble inflammatory mediators, which rely on JAK-STAT signaling, and inhibition of this pathway using JAK inhibitors might be a useful therapeutic strategy for these diseases. Growing evidence suggests that JAK inhibitors are efficacious in atopic dermatitis, alopecia areata, psoriasis, and vitiligo. Additional evidence suggests that JAK inhibition might be broadly useful in dermatology, with early reports of efficacy in several other conditions. JAK inhibitors can be administered orally or used topically and represent a promising new class of medications. The use of JAK inhibitors in dermatology is reviewed here.

Janus kinase (JAK) inhibitors for the treatment of skin and hair disorders: a review of literature

Janus kinase family (JAKs) has recently attracted the attention of many researchers, and several JAK inhibitor drugs have been developed targeting different members of the JAK family. Tofacitinib and ruxolitinib are US FDA approved drugs in this family for rheumatoid arthritis and myeloproliferative diseases, respectively. Dysregulation of JAK/STAT pathway is also involved in many skin diseases, specifically inflammatory disorders. The JAK/STAT signaling pathway and its involvement in skin diseases are overviewed in this study. We also review clinical studies of JAK inhibitors in field of dermatology, including psoriasis, atopic dermatitis, alopecia areata and vitiligo. Although the available evidence shows promising results, it is still too early to draw a firm conclusion about the place of these drugs in dermatological treatment.

JAK-STAT6 Pathway Inhibitors Block Eotaxin-3 Secretion by Epithelial Cells and Fibroblasts from Esophageal Eosinophilia Patients: Promising Agents to Improve Inflammation and Prevent Fibrosis in EoE

BACKGROUND

Although most studies on treatments for eosinophilic esophagitis (EoE) have focused on effects in the epithelium, EoE is a transmural disease. Eosinophils that infiltrate the subepithelial layers of the esophagus lead to fibrosis and the serious complications of EoE, and current therapies have shown minimal effects on this fibrosis. We aimed to elucidate T helper (Th)2 cytokine effects on esophageal fibroblasts and to explore potential fibroblast-targeted therapies for EoE.

METHODS

We established telomerase-immortalized fibroblasts from human esophageal biopsies. We stimulated these esophageal fibroblasts with Th2 cytokines, and examined effects of omeprazole and inhibitors of the Janus kinase (JAK)-signal transducer and activator of transcription (STAT6) pathway (AS1517499, leflunomide, and ruxolitinib) on STAT6 phosphorylation, STAT6 nuclear translocation, and eotaxin-3 expression. We also measured the effects of these inhibitors in esophageal epithelial cells stimulated with Th2 cytokines.

RESULTS

As in esophageal epithelial cells, Th2 cytokines increased STAT6 phosphorylation, STAT6 nuclear translocation, eotaxin-3 transcription and protein secretion in esophageal fibroblasts. Unlike in epithelial cells, however, omeprazole did not inhibit cytokine-stimulated eotaxin-3 expression in fibroblasts. In contrast, JAK-STAT6 pathway inhibitors decreased cytokine-stimulated eotaxin-3 expression in both fibroblasts and epithelial cells.

CONCLUSIONS

Omeprazole does not inhibit Th2 cytokine-stimulated eotaxin-3 expression by esophageal fibroblasts, suggesting that PPIs will have limited impact on subepithelial EoE processes such as fibrosis. JAK-STAT6 pathway inhibitors block Th2 cytokine-stimulated eotaxin-3 expression both in fibroblasts and in epithelial cells, suggesting a potential role for JAK-STAT inhibitors in treating both epithelial inflammation and subepithelial fibrosis in EoE.