Transcriptome profiling unveils the role of cholesterol in IL-17A signaling in psoriasis

Advance in Multi-omics Research Strategies on Cholesterol Metabolism in Psoriasis

The skin is a complex and dynamic organ where homeostasis is maintained through the intricate interplay between the immune system and metabolism, particularly cholesterol metabolism. Various factors such as cytokines, inflammatory mediators, cholesterol metabolites, and metabolic enzymes play crucial roles in facilitating these interactions. Dysregulation of this delicate balance contributes to the pathogenic pathways of inflammatory skin conditions, notably psoriasis. In this article, we provide an overview of omics biomarkers associated with psoriasis in relation to cholesterol metabolism. We explore multi-omics approaches that reveal the communication between immunometabolism and psoriatic inflammation. Additionally, we summarize the use of multi-omics strategies to uncover the complexities of multifactorial and heterogeneous inflammatory diseases. Finally, we highlight potential future perspectives related to targeted drug therapies and research areas that can advance precise medicine. This review aims to serve as a valuable resource for those investigating the role of cholesterol metabolism in psoriasis.

IL-17 Control of Cutaneous Immune Homeostasis

IL-17 is widely recognized for its roles in host defense and inflammatory disorders. However, it has become clear that IL-17 is also an essential regulator of barrier tissue physiology. Steady-state microbe sensing at the skin surface induces low-level IL-17 expression that enhances epithelial integrity and resists pathogens without causing overt inflammation. Recent reports describe novel protective roles for IL-17 in wound healing and counteracting physiologic stress; however, chronic amplification of these beneficial responses contributes to skin pathologies as diverse as fibrosis, cancer, and autoinflammation. In this paper, we discuss the context-specific roles of IL-17 in skin health and disease and therapeutic opportunities.

Cytokines in psoriasis: From pathogenesis to targeted therapy

Psoriasis is a multifactorial disease that affects 0.84% of the global population and it can be associated with disabling comorbidities. As patients present with thick scaly lesions, psoriasis was long believed to be a disorder of keratinocytes. Psoriasis is now understood to be the outcome of the interaction between immunological and environmental factors in individuals with genetic predisposition. While it was initially thought to be solely mediated by cytokines of type-1 immunity, namely interferon-γ, interleukin-2, and interleukin-12 because it responds very well to cyclosporine, a reversible IL-2 inhibitor; the discovery of Th-17 cells advanced the understanding of the disease and helped the development of biological therapy. This article aims to provide a comprehensive review of the role of cytokines in psoriasis, highlighting areas of controversy and identifying the connection between cytokine imbalance and disease manifestations. It also presents the approved targeted treatments for psoriasis and those currently under investigation.

Cholesterol and low-density lipoprotein as a cause of psoriasis: Results from bidirectional Mendelian randomization

BACKGROUND

Psoriasis is an inflammatory disease that affects many people. However, the causal effect of lipid metabolism on psoriasis has not yet been verified. This study aimed to identify the genetic relationship between serum lipid levels and psoriasis.

METHODS

Bidirectional two-sample Mendelian randomization (MR) was used to analyse the causal relationship between cholesterol and psoriasis. The outcome of the forward causality test was psoriasis. In the analysis of reverse causality, psoriasis was exposed, and 79 single-nucleotide polymorphisms were detected in the genome-wide association study (GWASs) database from the IEU GWASs Project. MR-Egger regression, inverse variance-weighted, weighted median, weighted mode and simple mode were used for the MR analyses.

RESULTS

The level of triglyceride, lipase member N, chylomicrons, extremely large very low-density lipoprotein (VLDL) particles, high-density lipoprotein (HDL) cholesterol levels, cholesterol esters in large HDL, cholesterol esters in medium HDL and cholesterol esters in medium VLDL have not affected the development of psoriasis. However, total cholesterol, total free cholesterol, low-density lipoprotein (LDL) cholesterol levels, cholesterol esters in large VLDL and cholesterol esters in medium LDL were unidirectional causal effects on psoriasis.

CONCLUSION

Bidirectional two-sample MR analysis indicated that high levels of total cholesterol, total free cholesterol, LDL cholesterol, cholesterol esters in large VLDL and cholesterol esters in medium LDL are genetic risk factors for psoriasis.

Endothelial IL17RD promotes Western diet-induced aortic myeloid cell infiltration

The Interleukin-17 (IL17) family is a group of cytokines implicated in the etiology of several inflammatory diseases. Interleukin-17 receptor D (IL17RD), also known as Sef (similar expression to fibroblast growth factor) belonging to the family of IL17 receptors, has been shown to modulate IL17A-associated inflammatory phenotypes. The objective of this study was to test the hypothesis that IL17RD promotes endothelial cell activation and consequent leukocyte adhesion. We utilized primary human aortic endothelial cells and demonstrated that RNAi targeting of IL17RD suppressed transcript levels by 83 % compared to non-targeted controls. Further, RNAi knockdown of IL17RD decreased the adhesion of THP-1 monocytic cells onto a monolayer of aortic endothelial cells in response to IL17A. Additionally, we determined that IL17A did not significantly enhance the activation of canonical MAPK and NFκB pathways in endothelial cells, and further did not significantly affect the expression of VCAM-1 and ICAM-1 in aortic endothelial cells, which is contrary to previous findings. We also determined the functional relevance of our findings in vivo by comparing the expression of endothelial VCAM-1 and ICAM-1 and leukocyte infiltration in the aorta in Western diet-fed Il17rd null versus wild-type mice. Our results showed that although Il17rd null mice do not have significant alteration in aortic expression of VCAM-1 and ICAM-1 in endothelial cells, they exhibit decreased accumulation of proinflammatory monocytes and neutrophils, suggesting that endothelial IL17RD induced in vivo myeloid cell accumulation is not dependent on upregulation of VCAM-1 and ICAM-1 expression. We further performed proteomics analysis to identify potential molecular mediators of the IL17A/IL17RD signaling axis. Collectively, our results underscore a critical role for Il17rd in the regulation of aortic myeloid cell infiltration in the context of Western diet feeding.

Identification of gene signatures and molecular mechanisms underlying the mutual exclusion between psoriasis and leprosy

Leprosy and psoriasis rarely coexist, the specific molecular mechanisms underlying their mutual exclusion have not been extensively investigated. This study aimed to reveal the underlying mechanism responsible for the mutual exclusion between psoriasis and leprosy. We obtained leprosy and psoriasis data from ArrayExpress and GEO database. Differential expression analysis was conducted separately on the leprosy and psoriasis using DEseq2. Differentially expressed genes (DEGs) with opposite expression patterns in psoriasis and leprosy were identified, which could potentially involve in their mutual exclusion. Enrichment analysis was performed on these candidate mutually exclusive genes, and a protein-protein interaction (PPI) network was constructed to identify hub genes. The expression of these hub genes was further validated in an external dataset to obtain the critical mutually exclusive genes. Additionally, immune cell infiltration in psoriasis and leprosy was analyzed using single-sample gene set enrichment analysis (ssGSEA), and the correlation between critical mutually exclusive genes and immune cells was also examined. Finally, the expression pattern of critical mutually exclusive genes was evaluated in a single-cell transcriptome dataset. We identified 1098 DEGs in the leprosy dataset and 3839 DEGs in the psoriasis dataset. 48 candidate mutually exclusive genes were identified by taking the intersection. Enrichment analysis revealed that these genes were involved in cholesterol metabolism pathways. Through PPI network analysis, we identified APOE, CYP27A1, FADS1, and SOAT1 as hub genes. APOE, CYP27A1, and SOAT1 were subsequently validated as critical mutually exclusive genes on both internal and external datasets. Analysis of immune cell infiltration indicated higher abundance of 16 immune cell types in psoriasis and leprosy compared to normal controls. The abundance of 6 immune cell types in psoriasis and leprosy positively correlated with the expression levels of APOE and CYP27A1. Single-cell data analysis demonstrated that critical mutually exclusive genes were predominantly expressed in Schwann cells and fibroblasts. This study identified APOE, CYP27A1, and SOAT1 as critical mutually exclusive genes. Cholesterol metabolism pathway illustrated the possible mechanism of the inverse association of psoriasis and leprosy. The findings of this study provide a basis for identifying mechanisms and therapeutic targets for psoriasis.

IL-17A Orchestrates Reactive Oxygen Species/HIF1α-Mediated Metabolic Reprogramming in Psoriasis

Immune cell-derived IL-17A is one of the key pathogenic cytokines in psoriasis, an immunometabolic disorder. Although IL-17A is an established regulator of cutaneous immune cell biology, its functional and metabolic effects on nonimmune cells of the skin, particularly keratinocytes, have not been comprehensively explored. Using multiomics profiling and systems biology-based approaches, we systematically uncover significant roles for IL-17A in the metabolic reprogramming of human primary keratinocytes (HPKs). High-throughput liquid chromatography-tandem mass spectrometry and nuclear magnetic resonance spectroscopy revealed IL-17A-dependent regulation of multiple HPK proteins and metabolites of carbohydrate and lipid metabolism. Systems-level MitoCore modeling using flux-balance analysis identified IL-17A-mediated increases in HPK glycolysis, glutaminolysis, and lipid uptake, which were validated using biochemical cell-based assays and stable isotope-resolved metabolomics. IL-17A treatment triggered downstream mitochondrial reactive oxygen species and HIF1α expression and resultant HPK proliferation, consistent with the observed elevation of these downstream effectors in the epidermis of patients with psoriasis. Pharmacological inhibition of HIF1α or reactive oxygen species reversed IL-17A-mediated glycolysis, glutaminolysis, lipid uptake, and HPK hyperproliferation. These results identify keratinocytes as important target cells of IL-17A and reveal its involvement in multiple downstream metabolic reprogramming pathways in human skin.

The causal relationship between pure hypercholesterolemia and psoriasis: A bidirectional, two-sample Mendelian randomization study

BACKGROUND

Several studies have reported the association between pure hypercholesterolemia (PH) and psoriasis, but the causal effect remains unclear.

METHODS

We explored the causal effect between PH and psoriasis using two-sample bidirectional Mendelian randomization (MR) analysis using data from genome-wide association studies. Single nucleotide polymorphisms related with exposures at the genome-wide significance level (p < 5×10-8 ) and less than the linkage disequilibrium level (r2  < 0.001) were chosen as instrumental variables. Subsequently, we used inverse variance weighting (IVW), MR-Egger and weighted median (WM) methods for causal inference. p < 0.05 was considered statistically significant. Heterogeneity was tested using Cochran's Q-test, and horizontal pleiotropy was examined using the MR-Egger intercept. Leave-one-out analyses were performed to assess the robustness and reliability of the results.

RESULTS

MR results showed a positive causal effect of PH on psoriasis [IVW: odds ratios (OR): 1.139, p = 0.032; MR-Egger: OR: 1.434, p = 0.035; WM: OR: 1.170, p = 0.045] and psoriatic arthritis (PsA) (IVW: OR: 1.210, p = 0.049; MR-Egger regression: OR: 1.796, p = 0.033; WM: OR: 1.317, p = 0.028). However, there is no causal relationship between PH and psoriasis vulgaris as well as other unspecified psoriasis. Inverse MR results suggested a negative causal relationship between PsA and PH (IVW: OR: 0.950, p = 0.037). No heterogeneity and horizontal pleiotropy exist, and these results were confirmed to be robust.

CONCLUSION

PH has a positive casual effect on psoriasis and PsA, and PsA may reduce the risk of having PH.

Metabolic influences on T cell in psoriasis: a literature review

Psoriasis is a systemic inflammatory disease that frequently coexists with various other conditions, such as essential hypertension, diabetes, metabolic syndrome, and inflammatory bowel disease. The association between these diseases may be attributed to shared inflammatory pathways and abnormal immunomodulatory mechanisms. Furthermore, metabolites also play a regulatory role in the function of different immune cells involved in psoriasis pathogenesis, particularly T lymphocytes. In this review, we have summarized the current research progress on T cell metabolism in psoriasis, encompassing the regulation of metabolites in glucose metabolism, lipid metabolism, amino acid metabolism, and other pathways within T cells affected by psoriasis. We will also explore the interaction and mechanism between psoriatic metabolites and immune cells. Moreover, we further discussed the research progress of metabolomics in psoriasis to gain a deeper understanding of its pathogenesis and identify potential new therapeutic targets through identification of metabolic biomarkers associated with this condition.

2-Hydroxypropyl-β-Cyclodextrin Treatment Induces Modest Immune Activation in Healthy Rhesus Macaques

Experimental simian immunodeficiency virus (SIV) infection of Asian macaques is an excellent model for HIV disease progression and therapeutic development. Recent coformulations of nucleoside analogs and an integrase inhibitor have been used for parenteral antiretroviral (ARV) administration in SIV-infected macaques, successfully resulting in undetectable plasma SIV RNA. In a cohort of SIVmac239-infected macaques, we recently observed that administration of coformulated ARVs resulted in an unexpected increase in plasma levels of soluble CD14 (sCD14), associated with stimulation of myeloid cells. We hypothesized that the coformulation solubilizing agent Kleptose (2-hydroxypropyl-β-cyclodextrin [HPβCD]) may induce inflammation with myeloid cell activation and the release of sCD14. Herein, we stimulated peripheral blood mononuclear cells (PBMCs) from healthy macaques with HPβCD from different commercial sources and evaluated inflammatory cytokine production in vitro. Treatment of PBMCs resulted in increased sCD14 release and myeloid cell interleukin-1β (IL-1β) production-with stimulation varying significantly by HPβCD source-and destabilized lymphocyte CCR5 surface expression. We further treated healthy macaques with Kleptose alone. In vivo, we observed modestly increased myeloid cell activation in response to Kleptose treatment without significant perturbation of the immunological transcriptome or epigenome. Our results demonstrate a need for vehicle-only controls and highlight immunological perturbations that can occur when using HPβCD in pharmaceutical coformulations. IMPORTANCE SIV infection of nonhuman primates is the principal model system for assessing HIV disease progression and therapeutic development. HPβCD has recently been incorporated as a solubilizing agent in coformulations of ARVs in SIV-infected nonhuman primates. Although HPβCD has historically been considered inert, recent findings suggest that HPβCD may contribute to inflammation. Herein, we investigate the contribution of HPβCD to healthy macaque inflammation in vitro and in vivo. We observe that HPβCD causes an induction of sCD14 and IL-1β from myeloid cells in vitro and demonstrate that HPβCD stimulatory capacity varies by commercial source. In vivo, we observe modest myeloid cell activation in blood and bronchoalveolar lavage specimens absent systemic immune activation. From our findings, it is unclear whether HPβCD stimulation may improve or diminish immune reconstitution in ARV-treated lentiviral infections. Our results demonstrate a need for vehicle-only controls and highlight immunological perturbations that can occur when using HPβCD in pharmaceutical coformulations.

Prurigo Nodularis onset during secukinumab treatment of psoriasis: a case report

BACKGROUND

Secukinumab has been approved by the U.S. FDA and the European Medicines Agency for the treatment of moderate-to-severe plaque psoriasis and psoriatic arthritis with the documented adverse effects. Here we reported in one case that a new symptom, Prurigo Nodularis (PN), developed during the programmed dosing of secukinumab.

CASE INTRODUCTION

A 22-years-old male with a 6-month history of severe plaque psoriasis vulgaris was presented to the dermatology clinic two weeks after the fifth serial weekly doses of secukinumab, for the reason of the outbreaks of multiple erythematous papules and pruritus nodules on the trunk and extremities. Physical examination showed that psoriatic rash were under effective control with the previous targeted therapy of secukinumab for plaque psoriasis vulgaris, but new dermatologic condition was spotted with multiple edematous red firm papules on the trunk and extremities, in the form of soy or hemispherical nodules, red in color, firm to touch, with some ulcerated crusts visible at tops, but negative Auspitz sign. Pathological examination confirmed these papules as PN.

CONCLUSION

This case report is shared to inform clinicians about an unannounced adverse effect of the secukinumab in the treatment of psoriasis, and it is recommended that patients be carefully informed of the possible risk of PN before starting treatment.

Hydrangea serrata Hot Water Extract and Its Major Ingredient Hydrangenol Improve Skin Moisturization and Wrinkle Conditions via AP-1 and Akt/PI3K Pathway Upregulation

Hydrangea serrata is a plant grown in Korea and Japan with a particular natural compound, hydrangenol. H. serrata has been researched for its anti-fungal properties, and ability to attenuate allergies and promote muscle growth. Its ability to reduce skin dryness is poorly understood. For that reason, we investigated whether H. serrata hot water extracts (Hs-WE) can moisturize keratinocytes. In clinical studies (Approval Code: GIRB-21929-NY and approval Date: 5 October 2021), skin wrinkles and skin moisturizing levels were improved in subjects applying 0.5% Hs-WE compared to the placebo group. We confirmed the components of Hs-WE from the LC/MS-MS analysis. Hs-WE and hydrangenol did not show cytotoxicity in HaCaT cells at all concentrations. Cell growth was also promoted by Hs-WE (5-20 µg/mL) and hydrangenol (15-60 µM) in a wound healing assay. Skin moisturizing factors were upregulated by the presence of Hs-WE or hydrangenol, and the hyaluronidases (HYAL) were inhibited at the mRNA level. Meanwhile, COL1A1 was increased by the presence of Hs-WE or hydrangenol. MAPK, AP-1, and Akt/PI3k signaling proteins, which are associated with cell proliferation and moisturizing factors, were increased by the administration of Hs-WE and hydrangenol. Has-1, 2, and 3 levels were enhanced via JNK when using the inhibitors of MAPK proteins and Hs-WE and hydrangenol, respectively. Taken together, Hs-WE could be used as cosmeceutical materials for improving skin conditions.

Artesunate targets cellular metabolism to regulate the Th17/Treg cell balance

INTRODUCTION

Metabolic reprogramming is one of the important mechanisms of cell differentiation, and different cells have different preferences for energy sources. During the differentiation of naive CD4 + T cells into Th17 and Treg cells, these cells show specific energy metabolism characteristics. Th17 cells depend on enhanced glycolysis, fatty acid synthesis, and glutaminolysis. In contrast, Treg cells are dependent on oxidative phosphorylation, fatty acid oxidation, and amino acid depletion. As a potent antimalarial drug, artesunate has been shown to modulate the Th17/Treg imbalance and regulate cell metabolism.

METHODOLOGY

Relevant literatures on ART, cellular metabolism, glycolysis, lipid metabolism, amino acid metabolism, CD4 + T cells, Th17 cells, and Treg cells published from January 1, 2010 to now were searched in PubMed database.

CONCLUSION

In this review, we will highlight recent advances in which artesunate can restore the Th17/Treg imbalance in disease states by altering T-cell metabolism to influence differentiation and lineage selection. Data from the current study show that few studies have focused on the effect of ART on cellular metabolism. ART can affect the metabolic characteristics of T cells (glycolysis, lipid metabolism, and amino acid metabolism) and interfere with their differentiation lineage, thereby regulating the balance of Th17/Treg and alleviating the symptoms of the disease.

Dyslipidemia and Inflammation as Hallmarks of Oxidative Stress in COVID-19: A Follow-Up Study

Recent works have demonstrated a significant reduction in cholesterol levels and increased oxidative stress in patients with coronavirus disease 2019 (COVID-19). The cause of this alteration is not well known. This study aimed to comprehensively evaluate their possible association during the evolution of COVID-19. This is an observational prospective study. The primary endpoint was to analyze the association between lipid peroxidation, lipid, and inflammatory profiles in COVID-19 patients. A multivariate regression analysis was employed. The secondary endpoint included the long-term follow-up of lipid profiles. COVID-19 patients presented significantly lower values in their lipid profile (total, low, and high-density lipoprotein cholesterol) with greater oxidative stress and inflammatory response compared to the healthy controls. Lipid peroxidation was the unique oxidative parameter with a significant association with the total cholesterol (OR: 0.982; 95% CI: 0.969-0.996; p = 0.012), IL1-RA (OR: 0.999; 95% CI: 0.998-0.999; p = 0.021) IL-6 (OR: 1.062; 95% CI: 1.017-1.110; p = 0.007), IL-7 (OR: 0.653; 95% CI: 0.433-0.986; p = 0.042) and IL-17 (OR: 1.098; 95% CI: 1.010-1.193; p = 0.028). Lipid abnormalities recovered after the initial insult during long-term follow-up (IQR 514 days); however, those with high LPO levels at hospital admission had, during long-term follow-up, an atherogenic lipid profile. Our study suggests that oxidative stress in COVID-19 is associated with derangements of the lipid profile and inflammation. Survivors experienced a recovery in their lipid profiles during long-term follow-up, but those with stronger oxidative responses had an atherogenic lipid profile.

Elevation of IgE in patients with psoriasis: Is it a paradoxical phenomenon?

Immunoglobulin E (IgE) elevation is a hallmark of allergic conditions such as atopic dermatitis (AD). The pathogenesis of AD is typically associated with high levels of IL-4 and IL-13 produced by activated T helper 2 (Th2) cells. Psoriasis, on the other hand, is an inflammatory skin disease mainly driven by Th17 cells and their related cytokines. Although the immunopathologic reactions and clinical manifestations are often easily distinguished in the two skin conditions, patients with psoriasis may sometimes exhibit AD-like manifestations, such as elevated IgE and persistent pruritic lesions. Given the fact that the effective T cells have great plasticity to re-differentiate in response to innate and environmental factors, this unusual skin condition could be a consequence of a cross-reaction between distinct arms of T-cell and humoral immunity. Here we review the literature concerning the roles of IgE in the development of AD and psoriasis, showing that elevated IgE seems to be an important indicator for this non-typical psoriasis.

PCSK9 Contributes to the Cholesterol, Glucose, and Insulin2 Homeostasis in Seminiferous Tubules and Maintenance of Immunotolerance in Testis

The PCSK9 contribution to cholesterol and immunotolerance homeostasis and response to glucose, and insulin in testis and hypophysis were studied using Pcsk9-deficient (-/-) and transgenic [Tg (PCSK9)] mice, and diabetic, obese ob/ob and db/db mice. The spermatids/spermatozoa acrosome, peritubular vessels, and epididymal adipocytes were PCSK9- and LDL-R-positive. The pro-PCSK9/PCSK9 ratio was high in interstitial tissue-fractions (ITf) and spermatozoa and low in seminiferous tubule-fractions (STf) in normal adult mice. This ratio decreased in ITf in ob/ob and db/db mice but increased in tubules in ob/ob mice. Deleting pcsk9 lowered cholesterol in serum but increased testicular cholesterol. Furthermore, HMGCoA-red, ACAT-2 and LDL-R turnover increased whereas SR-BI decreased in ITf; in tubules, ABCA1 decreased and 160 kDa LDL-R increased in Pcsk9 -/- mice. Excess testicular cholesterol could result from increased cholesterol synthesis and uptake with reduction in SR-BI-mediated efflux in ITf and from the overload of apoptotic cells, lowered ABCA1-mediated efflux and stimulated LDL-R protein synthesis in tubules in Pcsk9 -/- mice. Concomitantly with the cholesterol accumulation, tubules showed infiltrates of immune cells, elevated IL-17A and IL-17RA, and changes in the immunotolerance homeostasis. PCSK9 deficiency decreased glucose in tubules and spermatozoa while increasing insulin2 in ITf and tubules not serum. Moreover, IR-α, and IR-β augmented in tubules but decreased in the anterior pituitary; IR-α increased whereas IR-β decreased in ITf. The histology and cholesterol levels were normal in Tg (PCSK9) mouse testis. The excess cholesterol creates a milieu favorable to the action of high IL-17A and IL-17RA, the development of inflammatory conditions and self-tolerance breakdown in testis.

Punicalagin Alleviates Psoriasis by Inhibiting NF-κB-Mediated IL-1β Transcription and Caspase-1-Regulated IL-1β Secretion

Psoriasis is a chronic and inflammatory skin disorder characterized by inflammation and epidermal hyperplasia. Punicalagin (PUN) is a main active ingredient of pomegranate (Punica granatum L.) peel with multiple biological activities, such as antibacterial, antioxidant and anti-tumor effects. However, the potential effect of PUN on psoriasis remains unknown. In this study, we want to investigate the pharmacological effect of PUN on psoriasis by using imiquimod (IMQ)-induced psoriatic mice model in vivo and tumor necrosis factor a (TNF-α) and interleukin-17A (IL-17A)-stimulated HaCaT cells in vitro. Our results showed that PUN can effectively alleviate the severity of psoriasis-like symptoms. Mechanistically, PUN potently suppresses the aberrant upregulation of interleukin-1β (IL-1β) and subsequent IL-1β-mediated inflammatory cascade in keratinocytes by inhibiting the nuclear factor kappa B (NF-κB) activation and cleaved caspase-1 expression in vitro and in vivo. Taken together, our findings indicate that PUN can relieve psoriasis by repressing NF-κB-mediated IL-1β transcription and caspase-1-regulated IL-1β secretion, which provide evidence that PUN might represent a novel and promising candidate for the treatment of psoriasis.

TMT-based proteomics analysis reveals the protective effect of Jueyin granules on imiquimod-induced psoriasis mouse model by causing autophagy

BACKGROUND

Psoriasis is a chronic relapsing inflammatory skin disease that may markedly influence the patients' physical health and mental condition. According to animal models and clinical researches, it has been proved that Jueyin granules (JYG), a Chinese formula comprised of seven kinds of Traditional Chinese Medicine (TCM), is a therapeutic agent for treating psoriasis, while the specific mechanisms of the anti-inflammation effects of JYG have not been fully elucidated.

OBJECTIVE

To uncover the underlying mechanisms of the action of JYG on psoriasis by proteomics clues.

MATERIALS AND METHODS

Differentially expressed proteins (DEPs) were explored by tandem mass tag (TMT)-based quantitative proteomics analysis after JYG treatment (administered intragastrically for 12 days). Bioinformatics analysis of DEPs was conducted through hierarchical clustering, volcano plot, gene ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Major DEPs were further identified by enzyme-linked immunoassay (ELISA) and real-time quantitative polymerase chain reaction (qRT-PCR).

RESULTS

Ninety-five DEPs were identified, including 57 up-regulated and 38 down-regulated proteins, between imiquimod (IMQ) and IMQ+JYG groups. GO analysis indicated that DEPs were mainly associated with keratin filament, intermediate filament, extracellular exosome, extracellular space, innate immune response, keratinization, and keratinocyte differentiation. The KEGG pathway analysis manifested that estrogen signaling pathway, cholesterol metabolism, fat digestion, absorption, peroxisome proliferator-activated receptor (PPAR), and interleukin (IL)-17 signaling pathway might be the paramount pathways, through which JYG functioned on psoriasis. Furthermore, we determined that JYG could regulate macrophage and CD4+ T cell phenotypes by inducing autophagy.

CONCLUSIONS

JYG may induce autophagy by up-regulating ApoA1 and inhibit the infiltration of CD4+ T cells and macrophages, thereby alleviating IMQ-induced psoriatic inflammation.

Lipid metabolism in autoimmune rheumatic disease: implications for modern and conventional therapies

Suppressing inflammation has been the primary focus of therapies in autoimmune rheumatic diseases (AIRDs), including rheumatoid arthritis and systemic lupus erythematosus. However, conventional therapies with low target specificity can have effects on cell metabolism that are less predictable. A key example is lipid metabolism; current therapies can improve or exacerbate dyslipidemia. Many conventional drugs also require in vivo metabolism for their conversion into therapeutically beneficial products; however, drug metabolism often involves the additional formation of toxic by-products, and rates of drug metabolism can be heterogeneous between patients. New therapeutic technologies and research have highlighted alternative metabolic pathways that can be more specifically targeted to reduce inflammation but also to prevent undesirable off-target metabolic consequences of conventional antiinflammatory therapies. This Review highlights the role of lipid metabolism in inflammation and in the mechanisms of action of AIRD therapeutics. Opportunities for cotherapies targeting lipid metabolism that could reduce immunometabolic complications and potential increased cardiovascular disease risk in patients with AIRDs are discussed.

Recent Update on Immunopathogenesis of Psoriasis

Psoriasis is a chronic disabling complex inflammatory disorder prevalent worldwide with environmental and genetic components that involve predominantly skin in addition to nails and joints associated with various systemic comorbidities having periods of exacerbations and remissions. Psoriasis is characterized by hyper-proliferation as well as abnormal differentiation of epidermal keratinocytes and lymphocyte infiltration (mainly T cells) with resultant inflammatory cytokines and chemokines. Immunological and genetic studies over the last decade have identified genetic susceptibility risk alleles, molecular, cellular and immunological mechanisms involved in immunopathogenesis of psoriasis. The current disease model emphasizes the role of aberrant Th1 and Th17 responses regulated by a complex network of different cytokines, including TNF-α, IL-17 and IL-23; signal transduction pathways downstream to the cytokine receptors; and various activated transcription factors, including NF-κB, interferon regulatory factors and signal transducer and activator of transcriptions. Cytokines targeting biologics (IL-17, IL-23 and TNFα) therapies have revolutionized the management of severe skin disease having beneficial effects on joints and systemic inflammation of psoriasis as well. Further better understanding of immunopathogenesis of psoriasis will pave way for precision medicine based on specific immunopathogenic targets in a given phenotype of disease. Complex interplay of psoriasis with associated comorbidities is also a future area of research for overall better patient management and to improve their quality of life.

The role of metabolism in Th17 cell differentiation and autoimmune diseases

T helper 17 cells (Th17) have been associated with the pathogenesis of autoimmune and inflammatory diseases, which makes them become a sharp focus when the researchers are seeking therapeutic target for these diseases. A growing body of evidence has suggested that cellular metabolism dictates Th17 cell differentiation and effector function. Moreover, various studies have disclosed that metabolism is linked to the occurrence of autoimmune diseases. In this article, we reviewed the most recent findings regarding the importance of metabolism in Th17 cell differentiation and autoimmune diseases and also discussed the modulation mechanisms of glycolysis, fatty acid and cholesterol synthesis, and amino acids metabolism for Th17 cell differentiation. This review summarized the potential therapeutic or preventing strategies for Th17 cell-mediated autoimmune diseases.

Skin Barrier Dysregulation in Psoriasis

The skin barrier is broadly composed of two elements-a physical barrier mostly localised in the epidermis, and an immune barrier localised in both the dermis and epidermis. These two systems interact cooperatively to maintain skin homeostasis and overall human health. However, if dysregulated, several skin diseases may arise. Psoriasis is one of the most prevalent skin diseases associated with disrupted barrier function. It is characterised by the formation of psoriatic lesions, the aberrant differentiation and proliferation of keratinocytes, and excessive inflammation. In this review, we summarize recent discoveries in disease pathogenesis, including the contribution of keratinocytes, immune cells, genetic and environmental factors, and how they advance current and future treatments.

Analysis of the Potential Genetic Links between Psoriasis and Cardiovascular Risk Factors

Cardiovascular risk factors are one of the most common comorbidities in psoriasis. A higher prevalence of hypertension, insulin resistance and type 2 diabetes, dyslipidemia, obesity, metabolic syndrome, depression, as well as cardiovascular disease was confirmed in psoriatic patients in comparison to the general population. Data suggest that psoriasis and systemic inflammatory disorders may originate from the pleiotropic interactions with many genetic pathways. In this review, the authors present the current state of knowledge on the potential genetic links between psoriasis and cardiovascular risk factors. The understanding of the processes linking psoriasis with cardiovascular risk factors can lead to improvement of psoriasis management in the future.

Aberrations in Lipid Expression and Metabolism in Psoriasis

Psoriasis (PSO) is a common skin disease that affects about 1%-3% of the general population. It is a great medical, social and economic burden since PSO is associated with many comorbidities, of which the most common are cardiometabolic disorders. Psoriatic patients suffer more frequently from obesity, dyslipidemia, atherosclerosis, and nonalcoholic fatty liver disease. Research shows that lipid expression and metabolism disorders are present more often in such patients. This review focuses on a variety of aberrations in lipids in the skin, blood, and adipose tissue in psoriatic patients and their multifactorial impact on the pathogenesis of psoriasis.

IBDDB: a manually curated and text-mining-enhanced database of genes involved in inflammatory bowel disease

To date, research on inflammatory bowel disease (IBD, encompassing Crohn's disease and ulcerative colitis), a chronic complex disorder, has generated a large amount of data scattered across published literature (1 06 333) listed in PubMed on 14 October 2020, and no dedicated database currently exists that catalogues information on genes associated with IBD. We aimed to manually curate 289 genes that are experimentally validated to be linked with IBD and its known phenotypes. Furthermore, we have developed an integrated platform providing information about different aspects of these genes by incorporating several resources and an extensive text-mined knowledgebase. The curated IBD database (IBDDB) allows the selective display of collated 34 subject-specific concepts (listed as columns) exportable through a user-friendly IBDDB portal. The information embedded in concepts was acquired via text-mining of PubMed (manually cleaned and curated), accompanied by data-mining from varied resources. The user can also explore different biomedical entities and their co-occurrence with other entities (about one million) from 11 curated dictionaries in the indexed PubMed records. This functionality permits the user to generate and cross-examine a new hypothesis that is otherwise not easy to comprehend by just reading the published abstracts and papers. Users can download required information using various file formats and can display information in the form of networks. To our knowledge, no curated database of IBD-related genes is available so far. IBDDB is free for academic users and can be accessed at https://www.cbrc.kaust.edu.sa/ibd/.

The metabolism-modulating activity of IL-17 signaling in health and disease

IL-17 was discovered nearly 30 yr ago, but it has only been recently appreciated that a key function of this cytokine is to orchestrate cellular and organismal metabolism. Indeed, metabolic regulation is integrated into both the physiological and the pathogenic aspects of IL-17 responses. Thus, understanding the interplay between IL-17 and downstream metabolic processes could ultimately inform therapeutic opportunities for diseases involving IL-17, including some not traditionally linked to this cytokine pathway. Here, we discuss the emerging pathophysiological roles of IL-17 related to cellular and organismal metabolism, including metabolic regulation of IL-17 signal transduction.

Liangxue Jiedu Formula Improves Psoriasis and Dyslipidemia Comorbidity via PI3K/Akt/mTOR Pathway

The pathological mechanism of psoriasis and dyslipidemia comorbidity is unclear, and there are few reports on therapy. By establishing an animal model of ApoE^−/− mice induced by imiquimod (IMQ), we explored the effects of Liangxue Jiedu formula (LXJDF), a traditional Chinese herb medicine, on psoriasis and dyslipidemia comorbidity through PI3K/Akt/mTOR pathway. The experiment was divided into a control group, a model group, an LXJDF high-dose group, an LXJDF low-dose group, and a positive drug (atorvastatin) group. Each group of mice was given continuous oral administration once a day. After 3 weeks, the mice dorsal skins were smeared with 62.5 mg of 5% IMQ cream for five consecutive days and continued to be given the corresponding drugs. We observed the effects of LXJDF on skin lesion changes, PASI score, pathological characteristics, blood lipid levels (TC, TG, LDL, HDL, and oxLDL), liver pathology, inflammatory factors in the skin, and the protein expression of PI3K/Akt/mTOR pathway in both the skin and liver. The results showed that LXJDF could significantly improve the psoriasiform skin lesions of IMQ-induced ApoE^−/− mice, including the reduction of PASI, thinning of epidermal thickness, inhibition of hyperkeratosis and parakeratosis, and inflammatory infiltration in the dermis, and reduce lipid accumulation in the epidermal. LXJDF could regulate blood lipid levels, reduce liver inflammation, and protect the liver. LXJDF could significantly decrease the gene expressions of inflammatory factors IL-17A, IL-23, IL-6, and TNF-α in the skin. LXJDF showed specific inhibition of PI3K, Akt, mTOR protein, and its phosphorylation expressions. In conclusion, LXJDF exerts an intervention effect on psoriasis and dyslipidemia comorbidity via PI3K/Akt/mTOR and its phosphorylation pathway.

Pathogenesis of psoriasis in the "omic" era. Part III. Metabolic disorders, metabolomics, nutrigenomics in psoriasis

Psoriasis is a systemic disease that is strictly connected with metabolic disorders (insulin resistance, atherogenic dyslipidemia, arterial hypertension, and cardiovascular diseases). It occurs more often in patients with a more severe course of the disease. Obesity is specially an independent risk factor and it is associated with a worse treatment outcome because of the high inflammatory activity of visceral fatty tissue and the production of inflammatory mediators involved in the development of both psoriasis and metabolic disorders. However, in psoriasis the activation of the Th17/IL-17 and the abnormalities in the Th17/Treg balance axis are observed, but this pathomechanism does not fully explain the frequent occurrence of metabolic disorders. Therefore, there is a need to look for better biomarkers in the diagnosis, prognosis and monitoring of concomitant disorders and therapeutic effects in psoriasis. In addition, the education on the use of a proper diet as a prophylaxis for the development of the above disorders is an important element of holistic care for a patient with psoriasis. Diet may affect gene expression due to epigenetic modification which encompasses interactions of environment, nutrition and diseases. Patients with psoriasis should be advised to adopt proper diet and dietician support.

UVB-dependent inhibition of lipin-1 protects against proinflammatory responses in human keratinocytes

Lipin-1 is an Mg²⁺-dependent phosphatidate phosphatase (PAP1) that catalyzes a critical step in the synthesis of glycerophospholipids and is also a cotranscriptional regulator. The role of lipin-1 in the regulation of inflammatory responses has been extensively studied in various cell types but not in skin cells. In the present study, the function of lipin-1 in UVB-induced proinflammatory responses was assessed in normal human epidermal keratinocytes (NHEKs). UVB radiation downregulated lipin-1 expression. Lipin-1 inhibition was mediated by UVB-dependent sterol-response element binding protein-1 (SREBP-1) inhibition. The UVB-dependent inhibition of lipin-1 and SREBP-1 was mediated by AMPK activation. UVB-induced activation of JNK was dependent on AMPK activation and mediated lipin-1 inhibition. Prevention of UVB-mediated lipin-1 repression by introducing a lipin-1 expression vector stimulated IL-6 and IL-8 production, suggesting that lipin-1 inhibition attenuates UVB-induced IL-6 and IL-8 production. The downregulation of lipin-1 ameliorated UVB-induced NF-ĸB phosphorylation, which might be attributed to the suppression of UVB-induced accumulation of free fatty acids (FFAs). Pharmacological inhibition of PAP1 with propranolol suppressed UVB-induced production of IL-6 and IL-8 in NHEKs and reconstituted human skin models. Taken together, lipin-1 is downregulated by exposure to UVB radiation, which confers protection against UVB-induced proinflammatory responses; therefore, the inhibition of lipin-1 is a potential strategy for photoaging.

Reduced production and activity of an enzyme in skin cells helps protect them from damage caused by exposure to ultra-violet light. Minjung Chae and colleagues at the Amorepacific Corporation in Yongin, South Korea, identified an anti-inflammatory effect caused by the reduction in expression of the enzyme lipin-1 when skin cells are exposed to UVB radiation. These ultra-violet rays are associated with aging and increased risk of skin cancer. Lipin-1 is involved in making glycerophospholipid molecules, which are key components of the membranes surrounding and inside cells. Identifying the enzyme’s significance for inflammation in skin cells extends previous similar findings with other cell types. The research also uncovered aspects of the molecular mechanisms mediating the skin cell response. Inhibiting lipin-1 activity might reduce the damage sunlight causes to skin.

Review-Current Concepts in Inflammatory Skin Diseases Evolved by Transcriptome Analysis: In-Depth Analysis of Atopic Dermatitis and Psoriasis

During the last decades, high-throughput assessment of gene expression in patient tissues using microarray technology or RNA-Seq took center stage in clinical research. Insights into the diversity and frequency of transcripts in healthy and diseased conditions provide valuable information on the cellular status in the respective tissues. Growing with the technique, the bioinformatic analysis toolkit reveals biologically relevant pathways which assist in understanding basic pathophysiological mechanisms. Conventional classification systems of inflammatory skin diseases rely on descriptive assessments by pathologists. In contrast to this, molecular profiling may uncover previously unknown disease classifying features. Thereby, treatments and prognostics of patients may be improved. Furthermore, disease models in basic research in comparison to the human disease can be directly validated. The aim of this article is not only to provide the reader with information on the opportunities of these techniques, but to outline potential pitfalls and technical limitations as well. Major published findings are briefly discussed to provide a broad overview on the current findings in transcriptomics in inflammatory skin diseases.

Caveolin as a Universal Target in Dermatology

Caveolin-1 is strongly expressed in different dermal and subdermal cells and physically interacts with signaling molecules and receptors, among them with transforming growth factor beta (TGF-β), matrix metalloproteinases, heat shock proteins, toll-like and glucocorticoid receptors. It should therefore be heavily involved in the regulation of cellular signaling in various hyperproliferative and inflammatory skin conditions. We provide an overview of the role of the caveolin-1 expression in different hyperproliferative and inflammatory skin diseases and discuss its possible active involvement in the therapeutic effects of different well-known drugs widely applied in dermatology. We also discuss the possible role of caveolin expression in development of the drug resistance in dermatology. Caveolin-1 is not only an important pathophysiological factor in different hyperproliferative and inflammatory dermatological conditions, but can also serve as a target for their treatment. Targeted regulation of caveolin is likely to serve as a new treatment strategy in dermatology.

Cellular and Molecular Links between Autoimmunity and Lipid Metabolism

The incidence of atherosclerosis is higher among patients with several autoimmune diseases such as psoriasis, rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). It is well documented that innate immune cells including macrophages and dendritic cells sense lipid species such as saturated fatty acids and oxidized low-density lipoprotein and produce pro-inflammatory cytokines and chemokines. However, whether a hyperlipidemic environment also impacts autoimmune T cell responses has been unclear. Among CD4+ T cells, Th17 and follicular helper T (Tfh) cells are known to play pathogenic roles in the development of hyperlipidemiaassociated autoimmune diseases. This review gives an overview of the cellular and molecular mechanisms by which dysregulated lipid metabolism impacts the pathogenesis of autoimmune diseases, with specific emphasis on Th17 and Tfh cells.

(Inverse) Agonists of Retinoic Acid-Related Orphan Receptor γ: Regulation of Immune Responses, Inflammation, and Autoimmune Disease

Retinoic acid-related orphan receptor γt (RORγt) functions as a ligand-dependent transcription factor that regulates multiple proinflammatory genes and plays a critical role in several inflammatory and autoimmune diseases. Various endogenous and synthetic RORγ (inverse) agonists have been identified that regulate RORγ transcriptional activity, including many cholesterol intermediates and oxysterols. Changes in cholesterol biosynthesis and metabolism can therefore have a significant impact on the generation of oxysterol RORγ ligands and, consequently, can control RORγt activity and inflammation. These observations contribute to a growing literature that connects cholesterol metabolism to the regulation of immune responses and autoimmune disease. Loss of RORγ function in knockout mice and in mice treated with RORγ inverse agonists results in reduced production of proinflammatory cytokines, such as IL-17A/F, and increased resistance to autoimmune disease in several experimental rodent models. Thus, RORγt inverse agonists might provide an attractive therapeutic approach to treat a variety of autoimmune diseases.

IL-17A inhibition by secukinumab induces early clinical, histopathologic, and molecular resolution of psoriasis

BACKGROUND

Hyperactivity of the IL-23/IL-17 axis is central to plaque psoriasis pathogenesis. Secukinumab, a fully human mAb that selectively inhibits IL-17A, is approved for treatment of psoriasis, psoriatic arthritis, and ankylosing spondylitis. Secukinumab improves the complete spectrum of psoriasis manifestations, with durable clinical responses beyond 5 years of treatment. In the feed-forward model of plaque chronicity, IL-17A has been hypothesized as the key driver of pathogenic gene expression by lesional keratinocytes, but in vivo evidence in human subjects is lacking.

METHODS

We performed a randomized, double-blind, placebo-controlled study (NCT01537432) of patients receiving secukinumab at the clinically approved dose up to 12 weeks. We then correlated plaque and nonlesional skin transcriptomic profiles with histopathologic and clinical measures of efficacy.

RESULTS

After 12 weeks of treatment, secukinumab reversed plaque histopathology in the majority of patients and modulated thousands of transcripts. Suppression of the IL-23/IL-17 axis by secukinumab was evident at week 1 and continued through week 12, including reductions in levels of the upstream cytokine IL-23, the drug target IL-17A, and downstream targets, including β-defensin 2. Suppression of the IL-23/IL-17 axis by secukinumab at week 4 was associated with clinical and histologic responses at week 12. Secukinumab did not affect ex vivo T-cell activation, which is consistent with its favorable long-term safety profile.

CONCLUSION

Our data suggest that IL-17A is the critical node within the multidimensional pathogenic immune circuits that maintain psoriasis plaques and that early reduction of IL-17A-dependent feed-forward transcripts synthesized by hyperplastic keratinocytes favors plaque resolution.

Level of inflammatory cytokines tumour necrosis factor α, interleukins 12, 23 and 17 in patients with psoriasis in the context of metabolic syndrome

Introduction

Psoriasis is a chronic inflammatory skin disease with immunologic etiology.

Aim

To investigate the levels of the proinflammatory cytokines tumor necrosis factor α (TNF-α), interleukin 23 (IL-23) and IL-17 in patients with psoriasis and psoriatic arthritis with concomitant metabolic syndrome.

Material and methods

This study included 60 patients with severe psoriasis.

Results

In patients with arterial hypertension concomitant with psoriasis, no statistically significant differences in cytokine levels were observed. On the other hand, in the group of patients diagnosed with diabetes, an increased level of IL-17 was observed. In patients with lipid disorders, the results were similar to the results of patients with diabetes.

Conclusions

It is very important to study immunologic mechanisms responsible for the presence and severity of psoriasis, in order to personalize the therapy in the future and optimize the effect of action on the basic disease and on concomitant disorders.

Atopic Dermatitis Is an IL-13-Dominant Disease with Greater Molecular Heterogeneity Compared to Psoriasis

Atopic dermatitis (AD) affects up to 20% of children and adults worldwide. To gain a deeper understanding of the pathophysiology of AD, we conducted a large-scale transcriptomic study of AD with deeply sequenced RNA-sequencing samples using long (126-bp) paired-end reads. In addition to the comparisons against previous transcriptomic studies, we conducted in-depth analysis to obtain a high-resolution view of the global architecture of the AD transcriptome and contrasted it with that of psoriasis from the same cohort. By using 147 RNA samples in total, we found striking correlation between dysregulated genes in lesional psoriasis and lesional AD skin with 81% of AD dysregulated genes being shared with psoriasis. However, we described disease-specific molecular and cellular features, with AD skin showing dominance of IL-13 pathways, but with near undetectable IL-4 expression. We also demonstrated greater disease heterogeneity and larger proportion of dysregulated long noncoding RNAs in AD, and illustrated the translational impact, including skin-type classification and drug-target prediction. This study is by far the largest study comparing the AD and psoriasis transcriptomes using RNA sequencing and demonstrating the shared inflammatory components, as well as specific discordant cytokine signatures of these two skin diseases.

Impaired Homocysteine Metabolism Associated with High Plasma Interleukin-17A Levels, a Pro-Atherogenic Marker, in an Endogamous Population of North India

Background

Impaired homocysteine metabolism (IHM; hyperhomocysteinemia) has been linked with many complex disorders like cardiovascular diseases and immunological disturbances. However, studies understanding IHM in light of pro- and anti- atherogeneic markers like Interleukin-17A & -10 (IL-17A & IL-10) and Forkhead box p3 (Foxp3, a master transcription factor) are scarce.

Aim

In our present study, we aimed to understand the relation of IHM with plasma IL-17A and IL-10 levels and Foxp3 mRNA expression in peripheral blood mononuclear cells (PBMCs) from an endogamous population (Jats of Haryana, North India) with high prevalence of IHM without the concurrence of significant adverse cardiovascular outcomes.

Methods

Forty (40) clinically healthy individuals, unrelated up to first cousins, were recruited and were subjected to demographic, physiological and anthropometric profiling, followed by intravenous blood sample collection (fasting) and lipid profiling. Plasma homocysteine levels were estimated and individuals with homocysteine levels ≥ 15umol/L and <15umol/L were categorized as the impaired homocysteine metabolism group (IHM, n=30) and normal homocysteine metabolism group (NHM, n=10) respectively. Plasma folate and vitamin B12 and MTHFR C677T (methylenetetrahydrofolate reductase) polymorphism were detected. Relative mRNA expression of Foxp3 in PBMCs (normalized to 18S) was quantitated using SyBR green technology. Plasma IL-10 & 17 levels were estimated by ELISA assays.

Results and Conclusions

None of the physiological, anthropometric and lipid variables were different between the two groups. Foxp3 mRNA expression levels were relatively lower, and plasma IL-10 levels were found to be comparable among IHM and NHM group. However, significantly higher IL-17A levels and relatively high LDL cholesterol levels were present in the IHM group as compared with NHM. Our findings suggest that the Jats of Haryana, North India, exhibiting high levels of homocysteine, might also carry the high IL-17A -pro-atherogenic marker, suggesting an increasing burden of pre-morbid condition. This apparently does not reach to significant mortality/morbidity attributed to the counter action or balancing act of IL-10 (an anti-atherogenic marker). This further suggests environment-influenced epigenetic control mechanisms of the targeted genes in the present population.

Fluorescent light exposure incites acute and prolonged immune responses in zebrafish (Danio rerio) skin

Artificial light produces an emission spectrum that is considerably different than the solar spectrum. Artificial light has been shown to affect various behavior and physiological processes in vertebrates. However, there exists a paucity of data regarding the molecular genetic effects of artificial light exposure. Previous studies showed that one of the commonly used fluorescent light source (FL; 4100K or "cool white") can affect signaling pathways related to maintenance of circadian rhythm, cell cycle progression, chromosome segregation, and DNA repair/recombination in the skin of male Xiphophorus maculatus. These observations raise questions concerning the kinetics of the FL induced gene expression response, and which biological functions become modulated at various times after light exposure. To address these questions, we exposed zebrafish to 4100K FL and utilized RNA-Seq to assess gene expression changes in skin at various times (1 to 12h) after FL exposure. We found 4100K FL incites a robust early (1-2h) transcriptional response, followed by a more protracted late response (i.e., 4-12h). The early transcriptional response involves genes associated with cell migration/infiltration and cell proliferation as part of an overall increase in immune function and inflammation. The protracted late transcriptional response occurs within gene sets predicted to maintain and perpetuate the inflammatory response, as well as suppression of lipid, xenobiotic, and melatonin metabolism.

PI3K/AKT/mTOR activation and autophagy inhibition plays a key role in increased cholesterol during IL-17A mediated inflammatory response in psoriasis

Psoriasis is an immune-mediated inflammatory disease of the skin. Previous studies including ours have shown that IL-17A plays a major role in its pathogenesis; however, its precise molecular mechanism of action is not well understood. Cytokines like TNF α and IL-23 are also important in mediating the disease and some studies have also reported autophagy as a novel mechanism by which cytokines controls the immune response. Herein, we investigated the effect of IL-17A on autophagy and reveal crosstalk between autophagy and cholesterol signaling in keratinocytes. Our results suggest that IL-17A stimulated keratinocytes activated PI3K/AKT/mTOR signaling and inhibited autophagy by simultaneously inhibiting autophagosome formation and enhancing autophagic flux. Western blotting was utilized to detect the expression of autophagic markers (LC3 and p62), PI3K, mTOR and AKT. Induction of autophagy by mTOR inhibitor rapamycin and/or starvation also inhibited the levels of IL-17A secreted IL-8, CCL20 and S100A7 in keratinocytes. Herein, we also observed that inhibition of autophagy by IL-17A was accompanied by enhanced cellular cholesterol levels which in turn regulated the autophagic flux. To investigate crosstalk between autophagy and cellular cholesterol, we used methyl-β-cyclodextrin (MβCD), which disrupts detergent-insoluble microdomains (DIMs) by depleting cells of cholesterol and checked autophagy. Decreased expression of LC3-II in psoriatic lesional skin compared to non-lesional skin and induction of autophagy by anti-psoriatic drug methotrexate in keratinocytes further confirms the role of autophagy in psoriasis. Our findings suggest that modulators of autophagy and/or cholesterol levels may be developed, and also may lead to new therapeutic agents for psoriasis treatment.

Retinoic acid-related Orphan Receptor γ (RORγ): connecting sterol metabolism to regulation of the immune system and autoimmune disease

Cholesterol and its metabolites are bioactive lipids that interact with and regulate the activity of various proteins and signaling pathways that are implicated in the control of a variety of physiological and pathological processes. Recent studies revealed that retinoic acid-related orphan receptors, RORα and γ, members of the ligand-dependent nuclear receptor superfamily, exhibit quite a wide binding specificity for a number of sterols. Several cholesterol intermediates and metabolites function as natural ligands of RORα and RORγ and act as agonists or inverse agonists. Changes in cholesterol homeostasis that alter the level or type of sterol metabolites in cells, can either enhance or inhibit ROR transcriptional activity that subsequently result in changes in the physiological processes regulated by RORs, including various immune responses and metabolic pathways. Consequently, this might negatively or positively impact pathologies, in which RORs are implicated, such as autoimmune disease, inflammation, metabolic syndrome, cancer, and several neurological disorders. Best studied are the links between cholesterol metabolism, RORγt activity, and their regulation of Th17 differentiation and autoimmune disease. The discovery that Th17-dependent inflammation is significantly attenuated in RORγ-deficient mice in several experimental autoimmune disease models, initiated a search for ROR modulators that led to the identification of a number of small molecular weight RORγ inverse agonists. The inverse agonists suppress Th17 differentiation and IL-17 production and protect against autoimmunity. Together, these studies suggest that RORγt may provide an attractive therapeutic target in the management of several (inflammatory) diseases.

Low vitamin D-modulated calcium-regulating proteins in psoriasis vulgaris plaques: S100A7 overexpression depends on joint involvement

Psoriasis is an inflammatory skin disease with or without joint involvement. In this disease, the thickened epidermis and impaired barrier are associated with altered calcium gradients. Calcium and vitamin D are known to play important roles in keratinocyte differentiation and bone metabolism. Intracellular calcium is regulated by calcium-sensing receptor (CASR), calcium release-activated calcium modulator (ORAI) and stromal interaction molecule (STIM). Other proteins modulated by vitamin D play important roles in calcium regulation e.g., calbindin 1 (CALB1) and transient receptor potential cation channel 6 (TRPV6). In this study, we aimed to investigate the expression of calcium-regulating proteins in the plaques of patients with psoriasis vulgaris with or without joint inflammation. We confirmed low calcium levels, keratinocyte hyperproliferation and an altered epidermal barrier. The CASR, ORAI1, ORAI3, STIM1, CALB1 and TRPV6 mRNA, as well as the sterol 27-hydroxylase (CYP27A1), 25-hydroxyvitamin D3 1-α-hydroxylase (CYP27B1) and 1,25-dihydroxyvitamin D3 24-hydroxylase (CYP24A1) protein levels were low in the plaques of patients with psoriasis. We demonstrated S100 calcium-binding protein A7 (S100A7) overexpression in the plaques of patients with psoriasis vulgaris with joint inflammation, compared with those without joint involvement. We suggest an altered capacity to regulate the intracellular Ca2+ concentration ([Ca2+]i), characterized by a reduced expression of CASR, ORAI1, ORAI3, STIM1, CALB1 and TRPV6 associated with diminished levels of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], which may be associated with an altered balance between keratinocyte proliferation and differentiation in the psoriatic epidermis. Additionally, differences in S100A7 expression depend on the presence of joint involvement.