IL-17 and TNF synergistically modulate cytokine expression while suppressing melanogenesis: potential relevance to psoriasis

Chest Wall Dermatitis Patterns Following Thoracoscopic Intercostal Nerve Cryoablation for Surgical Correction of Pectus Excavatum

BACKGROUND

Intercostal nerve cryoablation (INC) has been shown to reduce postoperative pain and length of stay following surgical correction of pectus excavatum (SCOPE). Some patients have developed chest wall dermatological symptoms after INC that can be mistaken for metal allergy or infection. The purpose of this study is to report the symptoms, severity, incidence, and treatment of post-cryoablation dermatitis.

METHODS

A retrospective single institution review was performed for patients who underwent SCOPE with and without INC between June 2016 and March 2023 to assess for incidence of postoperative dermatological findings. Characteristics associated with these findings were evaluated.

RESULTS

During study period, 383 patients underwent SCOPE, 165 (43.1%) without INC and 218 (56.9%) with. Twenty-three (10.6%) patients who received INC developed exanthems characteristic of post-cryoablation dermatitis with two distinct phenotypes identified. No patients who underwent SCOPE without INC developed similar manifestations. Early dermatitis, characterized by a painless, erythematous, and blanching rash across the anterior thorax, was observed in 16 patients, presenting on median postoperative day 6.0 [IQR 6.0-8.5], with median time to resolution of 23.0 [IQR 12-71.0] days after symptom onset. Late dermatitis, characterized by hyperpigmentation spanning the anterior thorax, was observed in 7 patients, presenting on median postoperative day 129.0 [IQR 84.5-240.0], with median time to resolution of 114.0 [IQR 48.0-314.3] days.

CONCLUSION

This is the first report of dermatological manifestations following SCOPE with INC, a phenomenon of unknown etiology and no known long-term sequela. In our experience, it is self-resolving and lacks systemic symptoms suggesting observation alone is sufficient for resolution.

LEVEL OF EVIDENCE

IV.

CD4+ T cell-associated cytokines induce a chronic pro-inflammatory phenotype in induced pluripotent stem cell-derived midbrain astrocytes

Astrocytes are mediators of homeostasis but contribute to neuroinflammation in Parkinson's disease (PD). Mounting evidence suggests involvement of peripheral immune cells in PD pathogenesis. Therefore, this study aimed to determine the potential role of peripheral immune secreted cytokines in modulating midbrain astrocyte reactivity. Human iPSC-derived midbrain astrocytes were exposed to 5% and 10% CD4+ T cell conditioned media (CD4CM) for 24 h, 72 h, and 7 days to assess chronic exposure. Additionally, astrocytes were exposed to the Th17 cell cytokine, IL-17A (10 ng/mL), alone and in combination with TNF-α (0.3 ng/mL) to assess potential synergistic effects of both cytokines at 24 h, 72 h, and 7 days. CD4CM induced acute and chronic alterations in midbrain astrocytes. Increased NFκB translocation to the nucleus, increased expression of the pro-inflammatory genes, IL-1β, CXCL10 at 24 h, C3, LCN2, IL-6 at 24 and 48 h, as well as an increase in their release of pro-inflammatory cytokines IL-6 and CXCL10 at both these time points were observed. A synergistic response to the combination of IL-17A and TNF-α on increasing inflammatory gene expression and cytokine release occurred. IL-17A and TNF-α increased intensity of S100β at 24 h, decreased nuclear area and increased circularity of astrocytes at 72 h. A synergistic effect on γH2AX intensity at 72 h and an increase in LDH release at 7 days was observed. Our results demonstrate that IL-17A and TNF-α act synergistically, enhancing midbrain astrocyte reactivity to a similar degree as CD4CM. This highlights the importance of the peripheral immune secreted cytokines in increasing the reactivity status of midbrain astrocytes, implicating their role in PD.

Regulatory gene network for coffee-like color morph of TYRP1 mutant of oujiang color common carp

BACKGROUND

Neither a TYRP1-mediated highly conserved genetic network underlying skin color towards optimum defense nor the pathological tendency of its mutation is well understood. The Oujiang Color Common Carp (Cyprinus carpio var. color) as a model organism, offering valuable insights into genetics, coloration, aquaculture practices, and environmental health. Here, we performed a comparative skin transcriptome analysis on TYRP1 mutant and wild fishes by applying a conservative categorical approach considering different color phenotypes.

RESULTS

Our results reveal that an unusual color phenotype may be sensitized with TYRP1 mutation as a result of upregulating several genes related to an anti-inflammatory autoimmune system in response to the COMT-mediated catecholamine neurotransmitters in the skin. Particularly, catecholamines-derived red/brown, red with blue colored membrane attack complex, and brown/grey colored reduced eumelanin are expected to be aggregated in the regenerated cells.

CONCLUSIONS

It is, thus, concluded that the regenerated cells with catecholamines, membrane attack complex, and eumelanin altogether may contribute to the formation of the unusual (coffee-like) color phenotype in TYRP1 mutant.

Enhancing Tranexamic Acid Penetration through AQP-3 Protein Triggering via ZIF-8 Encapsulation for Melasma and Rosacea Therapy

The systemic use of tranexamic acid (TA) as an oral drug can bring adverse reactions, while intradermal injection leads to pain and a risk of infection. Moreover, it is difficult for highly hydrophilic TA to penetrate the skin barrier that contains lots of hydrophobic lipid compounds, which poses enormous restrictions on its topical application. Current transdermal TA delivery strategies are suffering from low drug load rates, plus their synthesis complexity, time-consumption, etc. adding to the difficulty of TA topical application in clinical therapeutics. To increase the penetration of TA, a novel approach using TA-loaded ZIF-8 (TA@ZIF-8) is developed. The encapsulation efficiency of TA@ZIF-8 reaches ≈25% through physical adsorption and chemical bonding of TA indicates by theoretical simulation and the improved TA penetration is elevated through activating the aquaporin-3 (AQP-3) protein. Additionally, in vivo and in vitro experiments demonstrate the preponderance of TA@ZIF-8 for penetration ability and the advantages in intracellular uptake, minor cytotoxicity, and inhibition of melanogenesis and inflammatory factors. Moreover, clinical trials demonstrate the safety and efficacy of TA@ZIF-8 in the treatment of melasma and rosacea. This work presents a potential topical application of TA, free from the safety concerns associated with systemic drug administration.

Review: A Contemporary, Multifaced Insight into Psoriasis Pathogenesis

Psoriasis is a chronic recurrent inflammatory autoimmune pathology with a significant genetic component and several interferences of immunological cells and their cytokines. The complex orchestration of psoriasis pathogenesis is related to the synergic effect of immune cells, polygenic alterations, autoantigens, and several other external factors. The major act of the IL-23/IL-17 axis, strongly influencing the inflammatory pattern established during the disease activity, is visible as a continuous perpetuation of the pro-inflammatory response and keratinocyte activation and proliferation, leading to the development of psoriatic lesions. Genome-wide association studies (GWASs) offer a better view of psoriasis pathogenic pathways, with approximately one-third of psoriasis's genetic impact on psoriasis development associated with the MHC region, with genetic loci located on chromosome 6. The most eloquent genetic factor of psoriasis, PSORS1, was identified in the MHC I site. Among the several factors involved in its complex etiology, dysbiosis, due to genetic or external stimulus, induces a burst of pro-inflammatory consequences; both the cutaneous and gut microbiome get involved in the psoriasis pathogenic process. Cutting-edge research studies and comprehensive insights into psoriasis pathogenesis, fostering novel genetic, epigenetic, and immunological factors, have generated a spectacular improvement over the past decades, securing the path toward a specific and targeted immunotherapeutic approach and delayed progression to inflammatory arthritis. This review aimed to offer insight into various domains that underline the pathogenesis of psoriasis and how they influence disease development and evolution. The pathogenesis mechanism of psoriasis is multifaceted and involves an interplay of cellular and humoral immunity, which affects susceptible microbiota and the genetic background. An in-depth understanding of the role of pathogenic factors forms the basis for developing novel and individualized therapeutic targets that can improve disease management.

Research Progress in Skin Aging and Immunity

Skin aging is a complex process involving structural and functional changes and is characterized by a decrease in collagen content, reduced skin thickness, dryness, and the formation of wrinkles. This process is underpinned by multiple mechanisms including the free radical theory, inflammation theory, photoaging theory, and metabolic theory. The skin immune system, an indispensable part of the body's defense mechanism, comprises macrophages, lymphocytes, dendritic cells, and mast cells. These cells play a pivotal role in maintaining skin homeostasis and responding to injury or infection. As age advances, along with various internal and external environmental stimuli, skin immune cells may undergo senescence or accelerated aging, characterized by reduced cell division capability, increased mortality, changes in gene expression patterns and signaling pathways, and altered immune cell functions. These changes collectively impact the overall function of the immune system. This review summarizes the relationship between skin aging and immunity and explores the characteristics of skin aging, the composition and function of the skin immune system, the aging of immune cells, and the effects of these cells on immune function and skin aging. Immune dysfunction plays a significant role in skin aging, suggesting that immunoregulation may become one of the important strategies for the prevention and treatment of skin aging.

Reciprocal crosstalk between Th17 and mesothelial cells promotes metastasis-associated adhesion of ovarian cancer cells

BACKGROUND

IL-17A and TNF synergistically promote inflammation and tumorigenesis. Their interplay and impact on ovarian carcinoma (OC) progression are, however, poorly understood. We addressed this question focusing on mesothelial cells, whose interaction with tumor cells is known to play a pivotal role in transcoelomic metastasis formation.

METHODS

Flow-cytometry and immunohistochemistry experiments were employed to identify cellular sources of IL-17A and TNF. Changes in transcriptomes and secretomes were determined by bulk and single cell RNA sequencing as well as affinity proteomics. Functional consequences were investigated by microscopic analyses and tumor cell adhesion assays. Potential clinical implications were assessed by immunohistochemistry and survival analyses.

RESULTS

We identified Th17 cells as the main population of IL-17A- and TNF producers in ascites and detected their accumulation in early omental metastases. Both IL-17A and its receptor subunit IL-17RC were associated with short survival of OC patients, pointing to a role in clinical progression. IL-17A and TNF synergistically induced the reprogramming of mesothelial cells towards a pro-inflammatory mesenchymal phenotype, concomitantly with a loss of tight junctions and an impairment of mesothelial monolayer integrity, thereby promoting cancer cell adhesion. IL-17A and TNF synergistically induced the Th17-promoting cytokines IL-6 and IL-1β as well as the Th17-attracting chemokine CCL20 in mesothelial cells, indicating a reciprocal crosstalk that potentiates the tumor-promoting role of Th17 cells in OC.

CONCLUSIONS

Our findings reveal a novel function for Th17 cells in the OC microenvironment, which entails the IL-17A/TNF-mediated induction of mesothelial-mesenchymal transition, disruption of mesothelial layer integrity and consequently promotion of OC cell adhesion. These effects are potentiated by a positive feedback loop between mesothelial and Th17 cells. Together with the observed clinical associations and accumulation of Th17 cells in omental micrometastases, our observations point to a potential role in early metastases formation and thus to new therapeutic options.

Crosstalk: keratinocytes and immune cells in psoriasis

In the past, psoriasis was considered a skin disease caused only by keratinocyte disorders. However, the efficacy of immunosuppressive drugs and biologics used to treat psoriasis proves that psoriasis is an immune-mediated disease. Indeed, a variety of immune cells are involved in the pathogenesis of psoriasis, including dendritic cells, Th17 cells, and resident memory T cells. Furthermore, keratinocytes play a role in the development of psoriasis as immune cells by secreting antibacterial peptides, chemokines, tumor necrosis factor-α, interleukin (IL)-36, and IL-23. These immune cells and skin cells interact and drive the aberrant differentiation and proliferation of keratinocytes. This crosstalk between keratinocytes and immune cells critical in the pathogenesis of psoriasis forms an inflammatory loop, resulting in the persistence or exacerbation of psoriasis plaques.

Immune dysregulation and inflammation causing hypopigmentation in post kala-azar dermal leishmaniasis: partners in crime?

Post kala-azar dermal leishmaniasis (PKDL), a heterogeneous dermal sequela of visceral leishmaniasis (VL), is challenging in terms of its etiopathogenesis. Hypopigmentation is a consistent clinical feature in PKDL, but mechanisms contributing to the loss of melanocytes remains poorly defined. Like other hypopigmentary dermatoses - for example, vitiligo, psoriasis, and leprosy - the destruction of melanocytes is likely a multifactorial phenomenon, key players being immune dysregulation and inflammation. This review focuses on immunological mechanisms responsible for the 'murder' of melanocytes, prime suspects at the lesional sites being CD8+ T cells and keratinocytes and their criminal tools being proinflammatory cytokines, for example, IFN-γ, IL-6, and TNF-α. Collectively, these may cause decreased secretion of melanocyte growth factors, loss/attenuation of cell adhesion molecules and inflammasome activation, culminating in melanocyte death.

Reversing Gray Hair: Inspiring the Development of New Therapies Through Research on Hair Pigmentation and Repigmentation Progress

Hair graying is a common and visible sign of aging resulting from decreased or absence of melanogenesis. Although it has been established that gray hair greatly impacts people's mental health and social life, there is no effective countermeasure other than hair dyes. It has long been thought that reversal of gray hair on a large scale is rare. However, a recent study reported that individual gray hair darkening is a common phenomenon, suggesting the possibility of large-scale reversal of gray hair. In this article, we summarize the regulation mechanism of melanogenesis and review existing cases of hair repigmentation caused by several factors, including monoclonal antibodies drugs, tyrosine kinase inhibitors (TKIs), immunomodulators, other drugs, micro-injury, and tumors, and speculate on the mechanisms behind them. This review offers some insights for further research into the modulation of melanogenesis and presents a novel perspective on the development of clinical therapies, with emphasis on topical treatments.

Modulation of IL-17 backbone dynamics reduces receptor affinity and reveals a new inhibitory mechanism

Knowledge of protein dynamics is fundamental to the understanding of biological processes, with NMR and 2D-IR spectroscopy being two of the principal methods for studying protein dynamics. Here, we combine these two methods to gain a new understanding of the complex mechanism of a cytokine:receptor interaction. The dynamic nature of many cytokines is now being recognised as a key property in the signalling mechanism. Interleukin-17s (IL-17) are proinflammatory cytokines which, if unregulated, are associated with serious autoimmune diseases such as psoriasis, and although there are several therapeutics on the market for these conditions, small molecule therapeutics remain elusive. Previous studies, exploiting crystallographic methods alone, have been unable to explain the dramatic differences in affinity observed between IL-17 dimers and their receptors, suggesting there are factors that cannot be fully explained by the analysis of static structures alone. Here, we show that the IL-17 family of cytokines have varying degrees of flexibility which directly correlates to their receptor affinities. Small molecule inhibitors of the cytokine:receptor interaction are usually thought to function by either causing steric clashes or structural changes. However, our results, supported by other biophysical methods, provide evidence for an alternate mechanism of inhibition, in which the small molecule rigidifies the protein, causing a reduction in receptor affinity. The results presented here indicate an induced fit model of cytokine:receptor binding, with the more flexible cytokines having a higher affinity. Our approach could be applied to other systems where the inhibition of a protein-protein interaction has proved intractable, for example due to the flat, featureless nature of the interface. Targeting allosteric sites which modulate protein dynamics, opens up new avenues for novel therapeutic development.

Inflammatory Cues Direct Skin-Resident Type 1 Innate Lymphoid Cells to Adopt a Psoriasis-Promoting Identity

Innate lymphoid cells (ILCs) are gatekeepers in barrier organs, where they maintain tissue integrity and contribute to host defense as well as tissue repair. Inappropriate activation of ILCs, however, can lead to immunopathology with detrimental results. In this study, we focused on type 1 ILCs (ILC1s), which under inflammatory conditions constitute a poorly defined population with ambiguous functions. To delineate the properties of ILC1s in skin pathology, we used the well-established mouse model of imiquimod-induced psoriasis. Although ILC1s represented a minority among cutaneous lymphocytes in vehicle-treated controls, they rapidly expanded during early psoriasis and ultimately increased by >20-fold. This rapid increase was verified using two additional psoriasis models. Inflammatory ILC1s from imiquimod-treated skin were defined as CD44+, CXCR6+, and CD11b+ and substantially contributed to TNF-α and GM-CSF production, rendering them a potential candidate to shape the inflammatory infiltrate. In accordance with the psoriasis-specific microenvironment, skin ILC1s upregulated the IL-23 receptor whereas expression of the IL-12Rβ2 subunit was diminished. As a consequence, neutralization of IL-12 only had a minor impact, whereas blocking IL-23 reduced both ILC1 abundance and disease severity. Together, our findings identify skin ILC1s as a likely player in early psoriasis and a prospective target for therapeutic approaches.

Analysis of serum proteomics data identifies a quantitative association between beta-defensin 2 at baseline and clinical response to IL-17 blockade in psoriatic arthritis

OBJECTIVES

Despite several effective targeted therapies, biomarkers that predict whether a patient with psoriatic arthritis (PsA) will respond to a particular treatment are currently lacking.

METHODS

We analysed proteomics data from serum samples of nearly 2000 patients with PsA in placebo-controlled phase-III clinical trials of the interleukin-17 inhibitor secukinumab. To discover predictive biomarkers of clinical response, we used statistical learning with controlled feature selection. The top candidate was validated using an ELISA and was separately assessed in a trial of almost 800 patients with PsA treated with secukinumab or the tumour necrosis factor inhibitor adalimumab.

RESULTS

Serum levels of beta-defensin 2 (BD-2) at baseline were found to be robustly associated with subsequent clinical response (eg, American College of Rheumatology definition of 20%, 50% and 70% improvement) to secukinumab, but not to placebo. This finding was validated in two independent clinical studies not used for discovery. Although BD-2 is known to be associated with psoriasis severity, the predictivity of BD-2 was independent of baseline Psoriasis Area and Severity Index. The association between BD-2 and response to secukinumab was observed as early as 4 weeks and maintained up to 52 weeks. BD-2 was also found to predict response to treatment with adalimumab. Unlike in PsA, BD-2 was not predictive of response to secukinumab in rheumatoid arthritis.

CONCLUSIONS

In PsA, BD-2 at baseline is quantitatively associated with clinical response to secukinumab. Patients with high levels of BD-2 at baseline reach and sustain higher rates of clinical response after treatment with secukinumab.

Progression of Pre-Existing Vitiligo during Secukinumab Treatment for Psoriasis

Vitiligo has been considered an unexplained paradoxical phenomenon during biologics use. Herein, we report an adult case of progression of pre-existing vitiligo during secukinumab treatment for psoriasis, and we also examined the immunohistochemical changes in relation to biologics use. He was being administered monthly secukinumab of 300 mg dose for 2 years, and all psoriatic lesions were cleared, but pre-existing hypopigmented lesions became more distinct and larger than before unlike when using adalimumab. A skin biopsy of the hypopigmented lesion showed loss of epidermal melanocytes and absence of gp100 immune activities, and he was finally diagnosed with progression of pre-existing vitiligo. Immunohistochemical staining of vitiligo lesion showed decrease in interleukin-17 and tumor necrosis factor-α and increase in CD8+ T cells, interferon-γ, and CXCL10 after the use of secukinumab. In this study, we suggest that biologics-induced cytokine imbalance play a critical role in vitiligo progression in patients with chronic inflammatory diseases, including psoriasis.

Psoriatic disease and non-alcoholic fatty liver disease shared pathogenesis review

Psoriatic disease (PD) and non-alcoholic fatty liver disease (NAFLD) potentially share disease pathways given the numerous inflammatory pathways involved in both diseases and a higher prevalence of NAFLD in PD patients.  Metabolic syndrome and obesity are a key link between the two diseases, but even when controlling for this, associations between both diseases are still seen. Therapeutics that impact metabolic or inflammatory pathways may be impactful in both PD and NAFLD. In this review, we describe common inflammatory pathways contributing to both PD and NAFLD and critically review the potential impact of treatments for and on both diseases.

Association of rs4711998 of IL-17A, rs2275913 of IL-17A and rs763780 IL-17F gene polymorphisms with non-segmental vitiligo in a Mexican population

Vitiligo is the most common depigmenting disease characterized by achromic macules due to selective loss of melanocytes. The pathogenesis remains poorly elucidated, and multiple hypotheses exist regarding its pathogenesis. Evidence suggests that stress on melanocytes can result in activation of the immune system, and involvement of both activated cluster of differentiation (CD8+) cytotoxic and CD4+ T cells in the dysfunction, depigmentation, and apoptosis of melanocytes. Recent studies show that the interleukin 17 (IL-17) axis plays a central role in the pathogenesis of the disease. IL-17 is an important regulatory effector cytokine in this pathway. The aim of this study was to evaluate the association of IL-17A rs4711998 (-832A/G), IL-17A rs2275913 (-197G/A), and IL-17F rs763780 (7488A/G) with vitiligo in a Northeastern Mexican population. This was a case-control study and included 116 patients with vitiligo and 116 control subjects. Genotype characterization of IL-17A rs4711998 (-832A/G), IL-17A rs2275913 (-197G/A), and IL-17F rs763780 (7488A/G) was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. A p ≤ 0.05 was considered significant. It was observed that the combination of the genotypes GG/GA for IL-17F rs763780 (7488A/G) was associated with an increased risk for the development of vitiligo (OR 2.0943, 95% Cl 1.2375-3.5445, p = 0.0056). Regarding IL-17A rs4711998 (-832A/G) and IL-17A rs2275913 (-197G/A) genotyping, no association with vitiligo development was found. In conclusion, the SNP rs763780 in the IL-17F gene appears to be a risk factor for vitiligo development in this Mexican population and it may be useful in future studies, especially for the development of new therapies.

Investigating small molecule compounds targeting psoriasis based on cMAP database and molecular dynamics simulation

OBJECTIVE

Psoriasis (PSO) is a chronic inflammatory skin disease that severely affects the physical and mental health of patients. Drug resistance has been developed upon current drug treatments, and there is no specific therapy. The aim of this study was to screen promising novel drug candidates for PSO using molecular dynamics (MD) simulations.

METHODS

The data of PSO were downloaded from gene expression omnibus (GEO) database and subjected to variance analysis. Target proteins and small molecule compounds targeting PSO were predicted in the connective map (cMAP) database. Molecular docking, MD simulation, and trajectory analysis were conducted to predict the binding of target proteins to compounds.

RESULTS

1999 differentially expressed genes in PSO were obtained by differential analysis. Through cMAP database prediction, a low Score value of -45.69 for lymphocyte cell-specific protein-tyrosine kinase (LCK) was revealed, and aminogenistein was identified as the compound targeting LCK, and LCK was notably highly expressed in the PSO samples. The drugScore of the binding pocket P_0 was 0.814656, which was docked with aminogenistein. The results showed that there were more than one binding site between LCK and aminogenistein with binding energy less than -7.0 kJ/mol, and the docking was relatively stable. The results of root-mean-square deviation (RMSD), root-mean-square fluctuation (RMSF), Gyrate, number of hydrogen bonds and total free binding energy in MD simulations showed that the binding of aminogenistein to LCK was relatively solid.

CONCLUSION

Aminogenistein has good protein-ligand interaction and stability with LCK, a target of PSO, and is a novel drug candidate for PSO.

Does immune dysregulation contribute towards development of hypopigmentation in Indian post kala-azar dermal leishmaniasis?

Post kala-azar dermal leishmaniasis (PKDL), a sequel of apparently cured visceral leishmaniasis (VL) presents with papulonodular (polymorphic) or hypopigmented lesions (macular) and is the proposed disease reservoir. As hypopigmentation appears consistently in PKDL, especially the macular form, this study aimed to delineate immune factors that singly or in combination could contribute towards this hypopigmentation. At lesional sites, the presence of melanocytes and CD8⁺ T-cells was assessed by immunohistochemistry and mRNA expression of melanogenic markers (tyrosinase, tyrosinase-related protein-1 and MITF) by droplet digital PCR, while plasma levels of cytokines and chemokines were measured by a multiplex assay. In comparison with skin from healthy individuals, macular PKDL demonstrated a near total absence of Melan-A⁺ cells at dermal sites, while the polymorphic cases demonstrated a 3.2-fold decrease, along with a dramatic reduction in the expression of key enzymes related to the melanogenesis signalling pathway in both forms. The levels of circulating IFN-γ, IL-6, IL-2, IL-1β, TNF-α and IFN-γ-inducible chemokines (CXCL9/10/11) were elevated and was accompanied by an increased lesional infiltration of CD8⁺ T-cells. The proportion of CD8⁺ T-cells correlated strongly with plasma levels of IFN-γ (r = 0.8), IL-6 (r = 0.9, p < 0.05), IL-2 (r = 0.7), TNF-α (r = 0.9, p < 0.05) and IL-1β (r = 0.7), as also with CXCL9 (r = 0.5) and CXCL10 (r = 0.6). Taken together, the absence/reduction in Melan-A suggested hypopigmentation in PKDL was associated with the destruction of melanocytes, following the impairment of the melanogenesis pathway. Furthermore, the presence of CD8⁺ T-cells and an enhanced IFN-γ-associated immune milieu suggested the generation of a pro-inflammatory landscape that facilitated melanocyte dysfunction/destruction.

Post-Inflammatory Hypopigmentation: Review of the Etiology, Clinical Manifestations, and Treatment Options

Post-inflammatory hypopigmentation is a common acquired pigmentary disorder that is more prominent in skin of color, leading to great cosmetic and psychosocial implications. Often, a diagnosis with a pigmentary disorder can negatively impact an individual's health-related quality of life and may result in stigma. Although most cases of post-inflammatory hypopigmentation resolve spontaneously over time, a systematic diagnostic approach can help with identifying the underlying etiology and informing treatment strategies. It can be due to cutaneous inflammation, sequelae of inflammatory or infectious dermatoses, or dermatologic procedures. Therefore, a thorough understanding of the epidemiology, patient history, physical exam findings, and clinical features of post-inflammatory hypopigmentation phenomenon can explain the primary cause to providers and allow for patient education. It is also important to understand the various therapeutic approaches available and the efficacy of these options, which will inform providers to choose the appropriate therapy for patients. Although algorithms exist for classifying acquired disorders of hypopigmentation, there are no established algorithms for the diagnosis and treatment of post-inflammatory hypopigmentation, which warrants further exploration and discourse.

Bimekizumab for the treatment of moderate-to-severe plaque psoriasis: a meta-analysis of randomized clinical trials

Background:

Bimekizumab is a monoclonal IgG1 antibody that selectively inhibits both interleukin (IL)-17A and IL-17F, and is a promising drug for patients with moderate-to-severe plaque psoriasis.

Objectives:

This study aimed to assess the efficacy and safety of bimekizumab in treating patients with psoriasis and to determine the optimal maintenance dosing schedules of bimekizumab.

Methods and design:

Eligible trials were identified from PubMed, Cochrane Controlled Register of Trials, Embase, ClinicalTrials.gov, and Chinese medical databases. Only double-blind, randomized, active comparator, or placebo-controlled trials of bimekizumab treatment on patients with psoriasis were included in this study.

Results:

Five studies were identified, which included 2473 patients with moderate-to-severe plaque psoriasis. The results indicated that bimekizumab had better efficacy than placebo or active comparator for Psoriasis Area and Severity Index (PASI) 90 [risk ratio (RR) = 29.29, 1.52; 95% confidence interval (CI) = 10.30–83.30, 1.06–2.19], PASI 100 (RR = 59.87, 2.06; 95% CI = 15.06–237.99, 1.12–3.79), and Investigator’s Global Assessment scores of 0 or 1 (IGA 0/1) (RR = 21.55, 1.36; 95% CI = 9.25–50.19, 1.02–1.81). Faster onset of clinically meaningful responses was observed with bimekizumab compared with both active comparators (RR = 2.59; 95% CI = 1.32–5.10) and placebo (RR = 40.46; 95% CI = 13.19–124.13), with PASI 75 response observed at week 4 after one dose. Subgroup analysis showed no significant difference in the reduction of PASI scores between 320 mg q4w dosage and q8w dosage (RR = 1.00; 95% CI = 0.96–1.03). Rates of patients with adverse events (AEs) were comparable in the bimekizumab and active comparator groups (RR = 1.13; 95% CI = 1.01–1.26), and oral candidiasis was one of the most common treatment-emergent AEs.

Conclusion:

The results of this meta-analysis suggest that bimekizumab is more efficacious and has a rapid onset of action than active comparators and placebo in the treatment of moderate-to-severe plaque psoriasis. After 16 weeks of initial maintenance treatment, both bimekizumab maintenance dosing schedules (320 mg every 4 and 8 weeks) had similar efficacy.

Inflammatory response: The target for treating hyperpigmentation during the repair of a burn wound

Hyperpigmentation is a common complication in patients with burn injuries during wound healing; however, the mechanisms underlying its occurrence and development remain unclear. Recently, postinflammatory hyperpigmentation (PIH) was found to result from overproduction of melanin. Local or systemic inflammatory responses are often observed in patients who develop hyperpigmentation. However, we lack studies on the relationship between PIH and burn injury. Therefore, we comprehensively reviewed the existing literature on the melanogenesis of the skin, inflammatory mechanisms in pigmentation, and local or systemic alteration in inflammatory cytokines in patients suffering from burn trauma to elucidate the relationship between PIH and burn injury. We believe that this review will guide further research on regulating melanin production in the burn management process.

The Potential Importance of CXCL1 in the Physiological State and in Noncancer Diseases of the Cardiovascular System, Respiratory System and Skin

In this paper, we present a literature review of the role of CXC motif chemokine ligand 1 (CXCL1) in physiology, and in selected major non-cancer diseases of the cardiovascular system, respiratory system and skin. CXCL1, a cytokine belonging to the CXC sub-family of chemokines with CXC motif chemokine receptor 2 (CXCR2) as its main receptor, causes the migration and infiltration of neutrophils to the sites of high expression. This implicates CXCL1 in many adverse conditions associated with inflammation and the accumulation of neutrophils. The aim of this study was to describe the significance of CXCL1 in selected diseases of the cardiovascular system (atherosclerosis, atrial fibrillation, chronic ischemic heart disease, hypertension, sepsis including sepsis-associated encephalopathy and sepsis-associated acute kidney injury), the respiratory system (asthma, chronic obstructive pulmonary disease (COPD), chronic rhinosinusitis, coronavirus disease 2019 (COVID-19), influenza, lung transplantation and ischemic-reperfusion injury and tuberculosis) and the skin (wound healing, psoriasis, sunburn and xeroderma pigmentosum). Additionally, the significance of CXCL1 is described in vascular physiology, such as the effects of CXCL1 on angiogenesis and arteriogenesis.

The role of cytokines and vitamin D in vitiligo pathogenesis

Vitiligo is a pigment-related disease with a global prevalence of 0.2% to 1.8% associated with considerable burden on quality of life. The treatment is still a challenge because of relapses and/or incomplete re-pigmentation. Although the exact cause is still unclear, its pathogenesis seems to be justifiable with the autoimmune theory, supported by the results of clinical research. In this narrative review, we aimed to summarize the evidence related to cytokines and vitiligo development. This review is consisted of English articles published in PubMed and Google Scholar concerning levels of inflammatory mediators, especially interleukins, in vitiligo patients over the last 20 years. References of relevant articles were also considered for review. Crucial role of dysregulated levels of interleukins and their synergistic function to each other, in the onset or progression of the disease is evident. The theory of autoimmune vitiligo is reinforced by the results of the studies in the literature, due to the association of pathogenesis with increased secretion of pro-inflammatory mediators and reduction of anti-inflammatory mediators. Decreased vitamin D levels may have a considerable role in vitiligo development by affecting Th1- and Th17-related immune responses. Cytokines play an important role in the pathogenesis or progression of the disease. Moreover, we believe that decreased vitamin D level has a considerable role in vitiligo development by affecting Th1- and Th17-related immune responses.

Establishment and validation of evaluation models for post-inflammatory pigmentation abnormalities

Post-inflammatory skin hyper- or hypo-pigmentation is a common occurrence with unclear etiology. There is currently no reliable method to predict skin pigmentation outcomes after inflammation. In this study, we analyzed the 5 GEO datasets to screen for inflammatory-related genes involved in melanogenesis, and used candidate cytokines to establish different machine learning (LASSO regression, logistic regression and Random Forest) models to predict the pigmentation outcomes of post-inflammatory skin. Further, to further validate those models, we evaluated the role of these candidate cytokines in pigment cells. We found that IL-37, CXCL13, CXCL1, CXCL2 and IL-19 showed high predictive value in predictive models. All models accurately classified skin samples with different melanogenesis-related gene scores in the training and testing sets (AUC>0.7). Meanwhile, we mainly evaluated the effects of IL-37 in pigment cells, and found that it increased the melanin content and expression of melanogenesis-related genes (MITF, TYR, TYRP1 and DCT), also enhanced tyrosinase activity. In addition, CXCL13, CXCL1, CXCL2 and IL-19 could down-regulate the expression of several melanogenesis-related genes. In conclusion, evaluation models basing on machine learning may be valuable in predicting outcomes of post-inflammatory pigmentation abnormalities. IL-37, CXCL1, CXCL2, CXCL13 and IL-19 are involved in regulating post-inflammatory pigmentation abnormalities.

New aspects of the pathogenesis of psoriasis

Psoriasis is a chronic multi-factorial immune-mediated inflammatory disease of skin and joints. The variety of clinical forms of dermatosis is consistent with various pathogenetic features of the disease progress which have been significantly supplemented and reviewed recently. Knowledge of these mechanisms will improve and personalize the prescribed therapy. This study places the emphasis on modern ideas about the formation of T cell memory, the role of melanocytes and innate lymphoid cells. Development mechanisms of guttate and paradoxical psoriasis with important distinguishing characteristics are described separately. Today, knowledge of the molecular basis of the disease progression has led to the creation and introduction of a number of highly effective targeted drugs into clinical practice. Further developments related to the inhibition of resident memory cells, innate lymphoid cells, as well as the study of guttate psoriasis perpetuation and the occurrence of paradoxical psoriasis will significantly increase the effectiveness of the therapy.

Discovery of an Oral, Rule of 5 Compliant, Interleukin 17A Protein-Protein Interaction Modulator for the Potential Treatment of Psoriasis and Other Inflammatory Diseases

Interleukin 17A (IL-17A) is an interleukin cytokine whose dysregulation is implicated in autoimmune disorders such as psoriasis, and monoclonal antibodies against the IL-17A pathway are now well-established and very effective treatments. This article outlines the work that led to the identification of 23 as an oral, small-molecule protein-protein interaction modulator (PPIm) clinical development candidate. Protein crystallography provided knowledge of the key binding interactions between small-molecule ligands and the IL-17A dimer, and this helped in the multiparameter optimization toward identifying an orally bioavailable, Rule of 5 compliant PPIm of IL-17A. Overlap of early ligands led to a series of benzhydrylglycine-containing compounds that allowed the identification of dimethylpyrazole as a key substituent that gave PPIm with oral bioavailability. Exploration of the amino acid portion of the structure then led to dicyclopropylalanine as a group that gave potent and metabolically stable compounds, including the development candidate 23.

Molecular and cellular regulation of psoriatic inflammation

This review highlights the molecular and cellular mechanisms underlying psoriatic inflammation with an emphasis on recent developments which may impact on treatment approaches for this chronic disease. We consider both the skin and the musculoskeletal compartment and how different manifestations of psoriatic inflammation are linked. This review brings a focus to the importance of inflammatory feedback loops that exist in the initiation and chronic stages of the condition, and how close interaction between the epidermis and both innate and adaptive immune compartments drives psoriatic inflammation. Furthermore, we highlight work done on biomarkers to predict the outcome of therapy as well as the transition from psoriasis to psoriatic arthritis.

Therapeutic potential of MCC950, a specific inhibitor of NLRP3 inflammasome

NOD-like receptor protein 3 (NLRP3), an important intracellular pattern recognition receptor, is a component of the NLRP3 inflammasome along with apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC) and pro-caspase-1. Previous studies have shown that dysregulation of NLRP3 inflammasome may be associated with several human diseases, and therefore blocking NLRP3 inflammasome activation may represent a therapeutic strategy for various diseases. MCC950 is a specific small-molecule inhibitor that selectively blocks activation of the NLRP3 inflammasome. In recent years, research on MCC950 has expanded; its targets are gradually being elucidated, and its metabolism and toxicity have been a focus of study. Preclinical research of MCC950 has yielded promising findings, and MCC950 has shown good efficacy in the treatment of autoimmune diseases, cardiovascular diseases, metabolic diseases and other diseases. Furthermore, clinical trials of MCC950 and other inhibitors of NLRP3 inflammasome have also been conducted. In this review, we discuss the drug targets, metabolism, toxicity and preclinical and clinical research advances of MCC950. We further discuss the clinical therapeutic potential of MCC950 to provide insights for the further study and application of MCC950.

A Murine Point Mutation of Sgpl1 Skin Is Enriched With Vγ6 IL17-Producing Cell and Revealed With Hyperpigmentation After Imiquimod Treatment

Sphingosine-1-phosphate lyase is encoded by the Sgpl1 gene, degrades S1P, and is crucial for S1P homeostasis in animal models and humans. S1P lyase deficient patients suffer from adrenal insufficiency, severe lymphopenia, and skin disorders. In this study, we used random mutagenesis screening to identify a mouse line carrying a missense mutation of Sgpl1 (M467K). This mutation caused similar pathologies as Sgpl1 knock-out mice in multiple organs, but greatly preserved its lifespan, which M467K mutation mice look normal under SPF conditions for over 40 weeks, in contrast, the knock-out mice live no more than 6 weeks. When treated with Imiquimod, Sgpl1M467K mice experienced exacerbated skin inflammation, as revealed by aggravated acanthosis and orthokeratotic hyperkeratosis. We also demonstrated that the IL17a producing Vγ6+ cell was enriched in Sgpl1M467K skin and caused severe pathology after imiquimod treatment. Interestingly, hyperchromic plaque occurred in the mutant mice one month after Imiquimod treatment but not in the controls, which resembled the skin disorder found in Sgpl1 deficient patients. Therefore, our results demonstrate that Sgpl1M467K point mutation mice successfully modeled a human disease after being treated with Imiquimod. We also revealed a major subset of γδT cells in the skin, IL17 secreting Vγ6 T cells were augmented by Sgpl1 deficiency and led to skin pathology. Therefore, we have, for the first time, linked the IL17a and γδT cells to SPL insufficiency.

Real life long-term efficacy and safety of ixekizumab in moderate-to-severe psoriasis: a 192 weeks multicentric retrospective study - IL PSO (ITALIAN LANDSCAPE PSORIASIS)

Psoriasis is one of the commonest inflammatory skin diseases determining a very high impact on patients' quality of life and daily activities and relationships. Several biologic therapies have been approved through the years for the treatment of moderate-to-severe plaque psoriasis, and efficacy and safety profile have been analyzed in clinical trials. Ixekizumab is an immunoglobulin G subclass 4 monoclonal antibody that selectively targets and binds IL-17A with high specificity and affinity. Inhibiting IL-17A activity, ixekizumab reduces and turns down levels of inflammation, resulting in the clinical improvement of the disease. Long term efficacy and safety profile of ixekizumab have been investigated and reported in the UNCOVER trials, but in literature there are only few studies based on real life experience. We present the efficacy and safety profile of ixekizumab in a cohort of 779 patients affected by moderate-to-severe plaque psoriasis and treated with ixekizumab in 11 italian dermatology hospitals, with a follow-up of care until 192 weeks. This article is protected by copyright. All rights reserved.

The Dark Side of Melanin Secretion in Cutaneous Melanoma Aggressiveness

Skin cancers are among the most common cancers worldwide and are increasingly prevalent. Cutaneous melanoma (CM) is characterized by the malignant transformation of melanocytes in the epidermis. Although CM shows lower incidence than other skin cancers, it is the most aggressive and responsible for the vast majority of skin cancer-related deaths. Indeed, 75% of patients present with invasive or metastatic tumors, even after surgical excision. In CM, the photoprotective pigment melanin, which is produced by melanocytes, plays a central role in the pathology of the disease. Melanin absorbs ultraviolet radiation and scavenges reactive oxygen/nitrogen species (ROS/RNS) resulting from the radiation exposure. However, the scavenged ROS/RNS modify melanin and lead to the induction of signature DNA damage in CM cells, namely cyclobutane pyrimidine dimers, which are known to promote CM immortalization and carcinogenesis. Despite triggering the malignant transformation of melanocytes and promoting initial tumor growth, the presence of melanin inside CM cells is described to negatively regulate their invasiveness by increasing cell stiffness and reducing elasticity. Emerging evidence also indicates that melanin secreted from CM cells is required for the immunomodulation of tumor microenvironment. Indeed, melanin transforms dermal fibroblasts in cancer-associated fibroblasts, suppresses the immune system and promotes tumor angiogenesis, thus sustaining CM progression and metastasis. Here, we review the current knowledge on the role of melanin secretion in CM aggressiveness and the molecular machinery involved, as well as the impact in tumor microenvironment and immune responses. A better understanding of this role and the molecular players involved could enable the modulation of melanin secretion to become a therapeutic strategy to impair CM invasion and metastasis and, hence, reduce the burden of CM-associated deaths.

Estradiol suppresses psoriatic inflammation in mice by regulating neutrophil and macrophage functions

BACKGROUND

Psoriasis is a common inflammatory skin disease resulting from dysregulation of the IL-23/T_H17 immune axis. The prevalence and severity of psoriasis is higher in men than in women, although the underlying reasons for this are unclear.

OBJECTIVE

We studied whether estradiol, a female hormone, plays protective roles in imiquimod-induced psoriatic inflammation in mice by regulating neutrophil and macrophage functions.

METHODS

Wild-type mice and conditional knockout mice were ovariectomized, supplemented with placebo or estradiol pellets, and an imiquimod-containing cream applied.

RESULTS

Mice without endogenous ovarian hormones exhibited exacerbated psoriatic inflammation including increased production of IL-17A and IL-1β, which was reversed by exogenously added estradiol. The suppressive effect of estradiol on the production of IL-1β and IL-17A was abolished in mice lacking estrogen receptors in neutrophils and macrophages (Esr1^f/fEsr2^f/fLysM-Cre+ mice). IL-1β, which is required for production of IL-17A in the psoriasis model, was mainly produced by neutrophils and inflammatory macrophages. Estradiol suppressed IL-1β production from neutrophils and macrophages in mice both in vivo and in vitro and from human neutrophils in vitro.

CONCLUSION

Our results suggest a novel mechanism for sex-dependent differences in psoriasis clinical phenotypes that may shed new light on the pathology of psoriasis.

Interferon-gamma induces melanogenesis via post-translational regulation of tyrosinase

Melanogenesis (melanin pigment production) in melanocytes is canonically stimulated by the alpha melanocyte stimulating hormone (αMSH), which activates the cyclic-AMP-mediated expression of the melanocyte inducing transcription factor (MITF) and its downstream melanogenic genes, including the principal rate-limiting melanogenic enzyme tyrosinase (TYR). Here, we report that interferon-gamma (IFNG; type II interferon), but not interferon-alpha (a type I interferon), induces a noncanonical melanogenic pathway in mouse and human melanocytic cells. Inhibition of IFNG pathway by the JAK1/2 inhibitor ruxolitinib or knocking out Stat1 gene abrogated the IFNG-induced melanogenesis. Interestingly, IFNG-induced melanogenesis was independent of MITF. IFNG markedly increased the TYR protein expression but did not affect the mRNA expression, suggesting a post-translational regulatory mechanism. In contrast, IFNG had no effect on the expression of other melanogenesis-related proteins, for example, tyrosinase-related protein 1 (TYRP1) and dopachrome tautomerase (DCT). Glycosidase digestion assays revealed that IFNG treatment increased the mature glycosylated form of TYR, but not its de novo synthesis. Moreover, cycloheximide chase assay showed that degradation of TYR was decreased in IFNG-treated cells. These results suggest that the IFNG-STAT1 pathway regulates melanogenesis via regulation of the post-translational processing and protein stability of TYR.

LncRNA AGXT2L1-2:2 facilitates keratinocytes proliferation and inhibits apoptosis by interacting with estrogen-related receptor alpha in psoriasis

Our previous studies have revealed that long noncoding RNA (lncRNA) AGXT2L1-2:2 was highly expressed in keratinocytes of psoriasis. However, the functions of lnc-AGXT2L1-2:2 in keratinocytes remain unknown. Meanwhile, co-expression network analysis indicated lnc-AGXT2L1-2:2 could interact with estrogen-related receptor alpha (ERRα). In this study, interleukin (IL)-17A could stimulate the production of lnc-AGXT2L1-2:2 in keratinocytes, thus establishing an in vitro cellular model of psoriasis. Lnc-AGXT2L1-2:2 was overexpressed using lentiviral-vector and ERRα was downregulated with small interfering RNA. Then the effects of lnc-AGXT2L1-2:2 and ERRα on viability, apoptosis, and cell cycle in IL-17A-stimulated keratinocytes were assessed by CCK-8, EdU assay, and flow cytometry. We found that lnc-AGXT2L1-2:2 and ERRα both resulted in higher proliferation ability, lower apoptosis rates, and reduction of G0/G1 phase proportion. Furthermore, lnc-AGXT2L1-2:2 could promote the expression of ERRα and siERRα antagonized the effects of lnc-AGXT2L1-2:2 on the phenotypes above in IL-17A-induced keratinocytes. In conclusion, lnc-AGXT2L1-2:2 was found to promote keratinocytes proliferation, inhibit cell apoptosis and the effects of lnc-AGXT2L1-2:2 on keratinocytes are dependent on ERRα.

Selenium-Rich Yeast Peptide Fraction Ameliorates Imiquimod-Induced Psoriasis-like Dermatitis in Mice by Inhibiting Inflammation via MAPK and NF-κB Signaling Pathways

Psoriasis, a chronic and immune-mediated inflammatory disease, adversely affects patients’ lives. We previously prepared selenium-rich yeast peptide fraction (SeP) from selenium-rich yeast protein hydrolysate and found that SeP could effectively alleviate ultraviolet radiation-induced skin damage in mice and inhibited H₂O₂-induced cytotoxicity in cultured human epidermal keratinocyte (HaCaT) cells. This study aimed to investigate whether SeP had a protective effect on imiquimod (IMQ)-induced psoriasis-like dermatitis in mice and the underlying mechanisms. Results showed that SeP significantly ameliorated the severity of skin lesion in IMQ-induced psoriasis-like mouse model. Moreover, SeP treatment significantly attenuated the expression of key inflammatory cytokines, including interleukin (IL)-23, IL-17A, and IL-17F, in the dorsal skin of mice. Mechanistically, SeP application not only inhibited the activation of JNK and p38 MAPK, but also the translocation of NF-κB into the nucleus in the dorsal skin. Furthermore, SeP treatment inhibited the levels of inflammatory cytokines and the activation of MAPK and NF-κB signaling induced by lipopolysaccharide in HaCaT cells and macrophage cell line RAW264.7. Overall, our findings showed that SeP alleviated psoriasis-like skin inflammation by inhibiting MAPK and NF-κB signaling pathways, which suggested that SeP would have a potential therapeutic effect against psoriasis.

Is Apremilast a Safe Option in Patients with History of Melanoma? A Case Series and a Review of the Literature

BACKGROUND

Recently it has been reported that apremilast might promote melanogenesis and it would therefore not be safe to use this drug in patients with psoriasis who have a history of melanoma.

METHODS

From January 2017 to December 2020, we retrospectively identified, within a cohort of 635 patients in follow-up care for melanoma, 16 cases of patients with psoriasis treated with apremilast and history of melanoma. Patients were monitored at our unit for a mean duration of 36 months of follow up.

RESULTS

The use of apremilast, in our case series was, thus, effective in managing psoriasis without causing recurrence of previous melanoma or any new suspicious lesions which would need removal.

DISCUSSION

It has been speculated that apremilast might not be safe in patients who have a history of melanoma as it would be involved in the stimulation of melanogenesis and consequent possibility of recurrence of previous melanoma.

CONCLUSION

Our data show that none of the patients treated with apremilast developed recurrence of melanoma at 36 months of follow-up. Further studies are necessary to confirm the safety of apremilast in a larger number of patients with concurrent malignancies, specifically melanoma, and for a longer follow-up period.

Non-immune functions of inflammatory cytokines targeted by anti-psoriatic biologics: a review

PURPOSE

Psoriasis is an inflammatory disease characterized by skin thickening with silvery white desquamation due to dysregulated inflammatory pathways and elevated levels of inflammatory cytokines. Biologic agents targeting these inflammatory cytokines have brought about significant improvement in clearing psoriatic lesions in patients with moderate-to-severe psoriasis. Moreover, biologics exert both beneficial and detrimental effects on comorbidities in psoriasis, which include increased risk of cardiovascular events, metabolic syndrome, among other conditions. However, non-immune functions of cytokines targeted by biologics, and, hence, the potential risks and benefits of biologics for psoriasis to different organs/systems and comorbidities, have not been well elucidated.

RESULTS

This review summarizes current understanding of the pathogenesis of psoriasis-related comorbidities and emerging discoveries of roles of cytokines targeted in psoriasis treatment, including tumor necrosis factor α and interleukins 12, 23, and 17, aiming to complete the safety profile of each biologics and provide therapeutic implications on psoriasis-related comorbidities, and on diseases involving other organs or systems.

Effects of Topical Retinoids on Acne and Post-inflammatory Hyperpigmentation in Patients with Skin of Color: A Clinical Review and Implications for Practice

Acne is a common cause for post-inflammatory hyperpigmentation (PIH), particularly in patients with skin of color (SOC), and PIH is often more distressing to patients than the acne itself. Topical retinoids are approved for the treatment of acne and for pigmentation disorders such as melasma or mottled hyperpigmentation associated with photodamage; moreover, they have been shown to reduce hyperpigmentation in patients with SOC. Therefore, treatment with topical retinoids should be started as early as possible unless contraindicated. Use of novel formulations or application of commonly recommended moisturizers may help reduce irritation. Combining retinoids with other topical agents and procedures such as superficial chemical peels can help to improve hyperpigmentation. Primary acne lesions are likely to improve weeks before PIH resolves and helping patients manage their expectations may reduce frustration. Providing clinicians and researchers with more education about the presentation and management of dermatologic conditions in patients with SOC is also recommended.

The Expression Pattern of Genes Related to Melanogenesis and Endogenous Opioids in Psoriasis

The melanocortin system is a major regulator of stress responses in the skin and is responsible for the induction of melanin synthesis through activation of melanogenesis enzymes. The expression of both melanocortin system genes and melanogenesis enzyme genes is altered in psoriasis, and the focus here was on twelve genes related to the signal transduction between them. Additionally, five endogenous opioid system genes that are involved in cutaneous inflammation were examined. Quantitative real-time-PCR was utilized to measure mRNA expression in punch biopsies from lesional and non-lesional skin of psoriasis patients and from the skin of healthy control subjects. Most of the genes related to melanogenesis were down-regulated in patients (CREB1, MITF, LEF1, USF1, MAPK14, ICAM1, PIK3CB, RPS6KB1, KIT, and ATRN). Conversely, an up-regulation occurred in the case of opioids (PENK, PDYN, and PNOC). The suppression of genes related to melanogenesis is in agreement with the reported reduction in pigmentation signaling in psoriatic skin and potentially results from the pro-inflammatory environment. The increase in endogenous opioids can be associated with their involvement in inflammatory dysregulation in psoriasis.

Plaque-type psoriasis inhibitors

Psoriasis is a common inflammatory skin disorder, which is mediated by the immune system and affects 1-4% of the world's population. Psoriasis is caused by a complex interaction between the immune system, autoantigens, psoriasis-associated genetic factors, and various environmental factors. As a chronic disease requiring long-term treatment, psoriasis is associated with follow-up costs and an economic burden on the patients, their families, and healthcare systems. The current treatments for moderate-to-severe plaque psoriasis include topical therapy, phototherapy, and systemic drugs consisting of biological/non-biological drugs. Within the past two decades, recent biological therapies for psoriasis have rapidly advanced. Moreover, new bispecific agents have the potential for better disease control, while small molecule drugs offer a future alternative to biological drugs and the more cost-effective, long-term treatment of the disease. The present study aimed to review updated data regarding the inhibitors used to improve plaque psoriasis that contain biologics, bispecific agents, small molecules, and aptamers (either approved or in the research phase).

Vitiligo skin T cells are prone to produce type 1- and type 2-cytokines to induce melanocyte dysfunction and epidermal inflammatory response through JAK signaling

Vitiligo is a T cell-mediated inflammatory skin disorder characterized by the loss of epidermal melanocytes. However, the contribution of melanocytes to the physiopathology of the disease in response to the T cell microenvironment remains unclear. Here, using NanoString technology and multiplex ELISA, we show that active vitiligo perilesional skin is characterized by prominent type 1 and 2 associated immune responses. The vitiligo skin T cell secretome downregulated melanocyte function and adhesion, while increasing melanocyte mitochondrial metabolism and expression of inflammatory cytokines and chemokines by epidermal cells. The JAK1/2 inhibitor ruxolitinib strongly inhibited such effects on epidermal cells. Our data highlight that vitiligo is more complex than previously thought with prominent combined activities of both Th1- and Th2-related cytokines inducing inflammatory responses of epidermal cells. Melanocytes do not appear only to be a target of T cells in vitiligo but could actively contribute to perpetuate inflammation. JAK inhibitors could prevent the impact of T cells on epidermal cells and pigmentation, highlighting their potential clinical benefit in vitiligo.

Neutralization of IL-17 and treatment with IL-2 protects septic arthritis by regulating free radical production and antioxidant enzymes in Th17 and Tregs: An immunomodulatory TLR2 versus TNFR response

Septic arthritis is a destructive joint disease caused by Staphylococcus aureus. Synovial inflammation involved Th17 proliferation and down regulation of Treg population, thus resolution of inflammation targeting IL-17 may be important to control arthritis. Endogenous inhibition of IL-17 to regulate arthritic inflammation correlating with Th17/Treg cells TLR2 and TNFRs are not done. The role of SOD, CAT and GRx in relation to ROS production during arthritis along with expression of TLR2, TNFR1/TNFR2 in Th17/Treg cells of mice treated with IL-17A Ab/ IL-2 were studied. Increased ROS, reduced antioxidant enzyme activity was found in Th17 cells of SA infected mice whereas Treg cells of IL-17A Ab/ IL-2 treated group showed opposite effects. Neutralization of IL-17 after arthritis cause decreased TNFR1 and increased TNFR2 expression in Treg cells. Thus, neutralization of IL-17 or IL-2 treatment regulates septic arthritis by enhancing anti-inflammatory properties of Treg via antioxidant balance and modulating TLR2/TNFR response.

Interleukin-17A Drives IL-19 and IL-24 Expression in Skin Stromal Cells Regulating Keratinocyte Proliferation

IL-17A has been shown to be up-regulated in psoriasis lesions and is central to psoriasis pathogenesis. IL-19, along with other IL-20 subfamily cytokines such as IL-20 and IL-24, is induced by IL-17A and contributes especially to epidermal hyperplasia in psoriasis. However, the regulation, cellular sources of IL-19 and whether targeting of IL-17A by biologics influence IL-19 expression is not completely understood. To investigate the regulation of IL-19 by IL-17A in psoriasis, the imiquimod-induced psoriasis mouse (IMQ) model was used. Enhanced expression of IL-17A in the IMQ model was achieved by anti-IL-10 antibody treatment. Assessments of skin inflammation macroscopically, by histology and flow cytometry, all confirmed increased psoriatic symptoms. Interestingly, depletion of IL-10 markedly upregulated IL-23/IL-17 pathway related cytokines followed by a significant increase in IL-19 and IL-24. The up-regulation of IL-19 and IL-24, but not IL-17A, coincided with increased keratinocyte proliferation. To investigate the cellular source and effects of biologics on IL-19, human skin fibroblasts from healthy controls and psoriasis patients were cultured alone or co-cultured with activated memory CD4+ T cells. Besides IL-1β, IL-17A induced direct expression of IL-19 and IL-24 in skin fibroblasts and keratinocytes. Importantly, intrinsic higher expression of IL-19 in psoriatic skin fibroblasts was observed in comparison to healthy skin fibroblasts. Neutralization of IL-17A in the human skin fibroblast-T cell co-culture system significantly suppressed IL-19 and IL-24 expression. Together, our data show that IL-17A-induced IL-19 and IL-24 expression in skin stromal cells contribute to keratinocyte proliferation.

Identification of Sitogluside as a Potential Skin-Pigmentation-Reducing Agent through Network Pharmacology

Many traditional Chinese medicines (TCMs) with skin-whitening properties have been recorded in the Ben-Cao-Gang-Mu and in folk prescriptions, and some literature confirms that their extracts do have the potential to inhibit pigmentation. However, no systematic studies have identified the specific regulatory mechanisms of the potential active ingredients. The aim of this study was to screen the ingredients in TCMs that inhibit skin pigmentation through a network pharmacology system and to explore underlying mechanisms. We identified 148 potential active ingredients from 14 TCMs, and based on the average “degree” of the topological parameters, the top five TCMs (Fructus Ligustri Lucidi, Hedysarum multijugum Maxim., Ampelopsis japonica, Pseudobulbus Cremastrae Seu Pleiones, and Paeoniae Radix Alba) that were most likely to cause skin-whitening through anti-inflammatory processes were selected. Sitogluside, the most common ingredient in the top five TCMs, inhibits melanogenesis in human melanoma cells (MNT1) and murine melanoma cells (B16F0) and decreases skin pigmentation in zebrafish. Furthermore, mechanistic research revealed that sitogluside is capable of downregulating tyrosinase (TYR) expression by inhibiting the ERK and p38 pathways and inhibiting TYR activity. These results demonstrate that network pharmacology is an effective tool for the discovery of natural compounds with skin-whitening properties and determination of their possible mechanisms. Sitogluside is a novel skin-whitening active ingredient with dual regulatory effects that inhibit TYR expression and activity.

Autoimmunity in vitiligo: Therapeutic implications and opportunities

Vitiligo is an acquired chronic pigmentary disorder affecting the melanocytes, mainly in the skin and mucosae. It occurs due to the dynamic interaction between genetic and environmental factors leading to autoimmune destruction of melanocytes. Defects in melanocyte adhesion and increased oxidative stress further augment the immune response in vitiligo. It is a cosmetically disfiguring condition with a substantial psychological burden. Its autoimmune nature with resultant chronicity, variable responses to therapeutic modalities, and frequent recurrences have further diminished the quality of life. Hence, treatment should aim to provide more extended remission periods, prevent recurrences, provide good cosmetic outcomes and ensure patient satisfaction. These treatment goals seem plausible with the recent progress in our understanding of the complex pathogenic mechanisms underlying vitiligo at a molecular and genetic level. We provide a literature review of the pathogenic mechanisms and the therapies targeting these mechanisms.

Evaluating the Role of the Interleukin-23/17 Axis in Critically Ill COVID-19 Patients

Studies have hypothesized a potential role of the interleukin (IL)-23/17 axis in coronavirus disease 2019 (COVID-19). However, to date, levels of IL-23 and 17 have not been compared between critically ill COVID-19 patients and critically ill non-COVID-19 patients. IL-23 and 17 were measured on admission to the intensive care unit (ICU) in critically ill COVID-19 (N = 38) and critically ill non-COVID-19 (N = 34) patients with an equal critical illness severity. Critically ill non-COVID-19 patients did not have sepsis or septic shock on ICU admission. None of the enrolled patients had previously received corticosteroids. In our study, circulating IL-17 levels were higher in the COVID-19 patients. More specifically, critically ill COVID-19 patients had levels of 0.78 (0.05-1.8) pg/mL compared to 0.11 (0.05-0.9) pg/mL in the critically ill non-COVID-19 patients (p = 0.04). In contrast, IL-23 levels were comparable between groups. A group of patients hospitalized in the specialized COVID-19 clinic (N = 16) was also used to evaluate IL-17 and IL-23 levels with respect to COVID-19 severity. Non-critically ill COVID-19 patients had undetectable levels of both cytokines. Our results support the notion of inhibiting IL-17 in critical COVID-19 infection.

MicroRNA-378a-3p is overexpressed in psoriasis and modulates cell cycle arrest in keratinocytes via targeting BMP2 gene

Psoriasis is a chronic autoimmune skin disease driven by dysregulations at the cellular, genomic and genetic levels. MicroRNAs are key mediators of gene expression regulation. However, how microRNAs control the pathogenesis of psoriasis is still unclear. Here, we reported a significant up-regulation of miR-378a-3p (miR-378a) in skin biopsies from active psoriatic lesions while it was down-regulated after treatment with methotrexate or narrow-band ultraviolet B phototherapy. Using the keratinocyte in vitro model, we showed that miR-378a disturbed the cell cycle progression, causing cell cycle arrest at G1 phase. Transcriptomic analysis of keratinocytes with miR-378a overexpression and depletion revealed several important biological mechanisms related to inflammation and tight junction. Target mRNA transcript assessed by luciferase assay identified bone morphogenetic protein 2 as a novel target gene of miR-378a. These findings offer a mechanistic model where miR-378a contributes to the pathogenesis of psoriasis.