Identifying biomarkers in human psoriasis: revealed by a systems metabolomics approach

Antipsoriatic Effect of Silymarin NLCs Based Gel: In Vitro and In Vivo Activity

Psoriasis is a chronic inflammatory disorder affecting over 100 million people, requires long-term therapy. Current treatments offer only symptomatic relief. However, phytoconstituents-based therapies like Silymarin (SLM) have shown promising effects. The study aims to develop, optimize, and evaluate a novel stable SLM NLC gel to improve anti-psoriatic activity by enhancing its permeability and retention into the dermal layer. SLM NLC formulation was prepared and optimized using 32 full factorial designs. The formulation was evaluated for the particle size, PDI, zeta potential, and % entrapment efficiency, evaluated by Transmission electron microscopy and thermal analysis. The freeze dried and prepared NLC-loaded gel was evaluated for physicochemical parameters, ex-vivo, and in-vivo studies. SLM-loaded NLC shows 624 nm particle size, 0.41 PDI, 92.95% entrapment efficiency, and -31.6 mV zeta potential. The sphere form of NLCs was confirmed using TEM. Controlled drug release was observed in ex vivo studies, low PASI score compared to disease control. Further, the levels of IL-6, TNF-α, and NF-κB were also reduced. The results are supported by histopathology showing minimal parakeratosis indicated in the SLM NLC-treated group. Prepared NLC-based shows enhance topical penetration and decrease the thickness of psoriatic plaques in the in vivo study.

Metabolic coordination between skin epithelium and type 17 immunity sustains chronic skin inflammation

Inflammatory epithelial diseases are spurred by the concomitant dysregulation of immune and epithelial cells. How these two dysregulated cellular compartments simultaneously sustain their heightened metabolic demands is unclear. Single-cell and spatial transcriptomics (ST), along with immunofluorescence, revealed that hypoxia-inducible factor 1α (HIF1α), downstream of IL-17 signaling, drove psoriatic epithelial remodeling. Blocking HIF1α in human psoriatic lesions ex vivo impaired glycolysis and phenocopied anti-IL-17 therapy. In a murine model of skin inflammation, epidermal-specific loss of HIF1α or its target gene, glucose transporter 1, ameliorated epidermal, immune, vascular, and neuronal pathology. Mechanistically, glycolysis autonomously fueled epithelial pathology and enhanced lactate production, which augmented the γδ T17 cell response. RORγt-driven genetic deletion or pharmacological inhibition of either lactate-producing enzymes or lactate transporters attenuated epithelial pathology and IL-17A expression in vivo. Our findings identify a metabolic hierarchy between epithelial and immune compartments and the consequent coordination of metabolic processes that sustain inflammatory disease.

Metabolic rewiring of macrophages by epidermal-derived lactate promotes sterile inflammation in the murine skin

Dysregulated macrophage responses and changes in tissue metabolism are hallmarks of chronic inflammation in the skin. However, the metabolic cues that direct and support macrophage functions in the skin are poorly understood. Here, we show that during sterile skin inflammation, the epidermis and macrophages uniquely depend on glycolysis and the TCA cycle, respectively. This compartmentalisation is initiated by ROS-induced HIF-1α stabilization leading to enhanced glycolysis in the epidermis. The end-product of glycolysis, lactate, is then exported by epithelial cells and utilized by the dermal macrophages to induce their M2-like fates through NF-κB pathway activation. In addition, we show that psoriatic skin disorder is also driven by such lactate metabolite-mediated crosstalk between the epidermis and macrophages. Notably, small-molecule inhibitors of lactate transport in this setting attenuate sterile inflammation and psoriasis disease burden, and suppress M2-like fate acquisition in dermal macrophages. Our study identifies an essential role for the metabolite lactate in regulating macrophage responses to inflammation, which may be effectively targeted to treat inflammatory skin disorders such as 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.

Nuclear translocation of PKM2 mediates keratinocyte metabolic reprogramming in psoriasis

PKM2 mediates the Warburg effects and is crucial for tumorigenesis, but its role in hyperplastic skin disorders remains elusive. In this study, we investigated the function of PKM2 in psoriatic keratinocytes. We found that PKM2 expression and its nuclear translocation were induced in the epidermis of psoriasis patients, contributing to aerobic glycolysis and cell growth. Moreover, mass spectrometry combined with immunoprecipitation analysis revealed that PKM2 could interact with TRIM33, an E3 ubiquitin ligase in the nucleus, and this interaction is critical for the nuclear retention of PKM2. As a result of TRIM33-mediated ubiquitination, PKM2 nuclear protein kinase function is promoted, thus leading to the phosphorylation of STAT3. In addition, blocking PKM2 nuclear translocation abrogated TRIM33-triggered glycolysis and cell proliferation in keratinocytes. Taken together, our experiments demonstrate that ubiquitination regulates the nuclear retention of PKM2 in keratinocytes. Moreover, our results highlight a novel mechanism accounting for the metabolic reprogramming of keratinocytes in psoriasis patients.

Assessment of NADH/NAD+ Redox Imbalance in Psoriatic Lesions Using the FMSF Technique: Therapeutic Aspects

Mitochondrial dysfunction has been linked to psoriasis, and it may be an important underlying factor contributing to this disease. However, a precise methodology for assessing mitochondrial dysfunction has yet to be developed. One promising approach is to measure NADH autofluorescence from the affected skin areas. In this study, we show that Flow-Mediated Skin Fluorescence (FMSF) can be used for the non-invasive assessment of mitochondrial dysfunction in psoriasis. The fluorescence level at baseline and the half-time of ischemic growth (t1/2) derived from the FMSF traces can be used for the non-invasive assessment of NADH/NAD+ redox imbalance in psoriatic lesions compared to unaffected skin. These results are supported by an analysis of the key FMSF parameters: Reactive Hyperemia Response (RHR) and Hypoxia Sensitivity (HS). This method not only contributes to understanding the biochemical processes involved in the etiopathogenesis of psoriasis, but it also provides a basis for identifying new drug targets and improving the treatment process.

NMR-based metabolomic analysis for the effects of moxibustion on imiquimod-induced psoriatic mice

ETHNOPHARMACOLOGICAL RELEVANCE

Moxibustion is a traditional medical intervention of traditional Chinese medicine. It refers to the direct or indirect application of ignited moxa wool made of mugwort leaves to acupuncture points or other specific parts of the body for either treating or preventing diseases. Moxibustion has been proven to be effective in treating skin lesions of psoriasis.

AIM OF THE STUDY

This study was performed to elucidate molecular mechanisms underlying the effects of moxibustion treatment on imiquimod-induced psoriatic mice.

MATERIALS AND METHODS

We established an imiquimod (IMQ)-induced psoriatic mice (Model) and assessed the effects of moxibustion (Moxi) treatment on skin lesions of psoriatic mice by the PASI scores and expressions of inflammation-related factors relative to normal control mice (NC). We then performed nuclear magnetic resonance (NMR)-based metabolomic analysis on the skin tissues of the NC, Model and Moxi-treated mice to address metabolic differences among the three groups.

RESULTS

Moxi mice showed reduced PASI scores and decreased expressions of the pro-inflammatory cytokines IL-8, IL-17A and IL-23 relative to Model mice. Compared with the Model group, the NC and Moxi groups shared 9 characteristic metabolites and 4 significantly altered metabolic pathways except for taurine and hypotaurine metabolism uniquely identified in the NC group. To a certain extent, moxibustion treatment improved metabolic disorders of skin lesions of psoriatic mice by decreasing glucose, valine, asparagine, aspartate and alanine-mediated cell proliferation and synthesis of scaffold proteins, alleviating histidine-mediated hyperproliferation of blood vessels, and promoting triacylglycerol decomposition.

CONCLUSIONS

This study reveals the molecular mechanisms underlying the effects of moxibustion treatment on the skin lesions of psoriasis, potentially improving the clinical efficacy of moxibustion.

Psoriasis, Is It a Microdamage of Our "Sixth Sense"? A Neurocentric View

Psoriasis is considered a multifactorial and heterogeneous systemic disease with many underlying pathologic mechanisms having been elucidated; however, the pathomechanism is far from entirely known. This opinion article will demonstrate the potential relevance of the somatosensory Piezo2 microinjury-induced quad-phasic non-contact injury model in psoriasis through a multidisciplinary approach. The primary injury is suggested to be on the Piezo2-containing somatosensory afferent terminals in the Merkel cell−neurite complex, with the concomitant impairment of glutamate vesicular release machinery in Merkel cells. Part of the theory is that the Merkel cell−neurite complex contributes to proprioception; hence, to the stretch of the skin. Piezo2 channelopathy could result in the imbalanced control of Piezo1 on keratinocytes in a clustered manner, leading to dysregulated keratinocyte proliferation and differentiation. Furthermore, the author proposes the role of mtHsp70 leakage from damaged mitochondria through somatosensory terminals in the initiation of autoimmune and autoinflammatory processes in psoriasis. The secondary phase is harsher epidermal tissue damage due to the primary impaired proprioception. The third injury phase refers to re-injury and sensitization with the derailment of healing to a state when part of the wound healing is permanently kept alive due to genetical predisposition and environmental risk factors. Finally, the quadric damage phase is associated with the aging process and associated inflammaging. In summary, this opinion piece postulates that the primary microinjury of our “sixth sense”, or the Piezo2 channelopathy of the somatosensory terminals contributing to proprioception, could be the principal gateway to pathology due to the encroachment of our preprogrammed genetic encoding.

Circulating Metabolomic Signature in Generalized Pustular Psoriasis Blunts Monocyte Hyperinflammation by Triggering Amino Acid Response

Generalized pustular psoriasis (GPP), the most grievous variant of psoriasis, is featured by dysregulated systemic inflammatory response. The cellular and molecular basis of GPP is poorly understood. Blood monocytes are key players of host defense and producers of inflammatory cytokines including IL-1β. How the immune response of monocytes is affected by metabolic internal environment in GPP remains unclear. Here, we performed a metabolomic and functional investigation of GPP serum and monocytes. We demonstrated a significant increase in IL-1β production from GPP monocytes. In GPP circulation, serum amyloid A (SAA), an acute-phase reactant, was dramatically increased, which induced the release of IL-1β from monocytes in a NLRP3-dependent manner. Using metabolomic analysis, we showed that GPP serum exhibited an amino acid starvation signature, with glycine, histidine, asparagine, methionine, threonine, lysine, valine, isoleucine, tryptophan, tyrosine, alanine, proline, taurine and cystathionine being markedly downregulated. In functional assay, under amino acid starvation condition, SAA-stimulated mature IL-1β secretion was suppressed. Mechanistically, at post-transcriptional level, amino acid starvation inhibited the SAA-mediated reactive oxygen species (ROS) formation and NLRP3 inflammasome activation. Moreover, the immune-modulatory effect of amino acid starvation was blocked by silencing general control nonderepressible 2 kinase (GCN2), suggesting the involvement of amino acid response (AAR) pathway. Collectively, our results suggested that decreased serum amino acids in GPP blunted the innate immune response in blood monocytes through AAR pathway, serving as a feedback mechanism preventing excessive inflammation in GPP.

Serum metabolic fingerprinting of psoriasis and psoriatic arthritis patients using solid-phase microextraction-liquid chromatography-high-resolution mass spectrometry

INTRODUCTION

Psoriatic arthritis (PsA), an inflammatory arthritis that develops in individuals with psoriasis, is associated with reduced quality of life. Identifying biomarkers associated with development of PsA as well as with PsA disease activity may help management of psoriatic disease.

OBJECTIVES

To use metabolomic fingerprinting to determine potential candidate markers of disease conversion (psoriasis to PsA) and/or PsA activity.

METHODS

A novel sample preparation protocol based on solid-phase microextraction (SPME) was used to prepare serum samples obtained from: (1) individuals with psoriasis, some of whom develop psoriatic arthritis (n = 20); (2) individuals with varying PsA activity (mild, moderate, severe; n = 10 each) and (3) healthy controls (n = 10). Metabolomic fingerprinting of the obtained extracts was performed using reversed-phase liquid chromatography coupled to high resolution mass spectrometry.

RESULTS

Psoriasis patients who developed PsA had similar metabolomic profiles to patients with mild PsA and were also indistinguishable from patients with psoriasis who did not develop PsA. Elevated levels of selected long-chain fatty acids (e.g., 3-hydroxytetradecanedioic acid) that are associated with dysregulation of fatty acid metabolism, were observed in patients with severe PsA. In addition, 1,11-undecanedicarboxylic acid-an unusual fatty acid associated with peroxisomal disorders-was also identified as a classifier in PsA patients vs. healthy individuals. Furthermore, a number of different eicosanoids with either pro- or anti-inflammatory properties were detected solely in serum samples of patients with moderate and severe PsA.

CONCLUSION

A global metabolomics approach was employed to analyze the serum metabolome of patients with psoriasis, PsA, and healthy controls in order to examine potential differences in the biochemical profiles at a metabolite level. A closer examination of circulating metabolites may potentially provide markers of PsA activity.

Large-scale plasma-metabolome analysis identifies potential biomarkers of psoriasis and its clinical subtypes

BACKGROUND

Psoriasis is an immune-mediated skin disease for which the crosstalk between genetic and environmental factors is responsible. To date, no definitive diagnostic criteria for psoriasis yet, and specific biomarkers are required.

OBJECTIVE

We performed metabolome analysis to identify metabolite biomarkers of psoriasis and its subtypes such as psoriatic arthritis (PsA) and cutaneous psoriasis (PsC).

METHODS

We constructed metabolomics profiling of 130 plasma samples (42 PsA patients, 50 PsC patients, and 38 healthy controls) using a nontargeted metabolomics approach.

RESULTS

Psoriasis-control association tests showed that one metabolite (ethanolamine phosphate) was significantly increased in psoriasis samples than in the controls, whereas three metabolites decreased (false discovery rate [FDR] < 0.05; XA0019, nicotinic acid, and 20α-hydroxyprogesterone). In the association test between PsA and PsC, tyramine significantly increased in PsA than in PsC, whereas mucic acid decreased (FDR < 0.05). Molecular pathway analysis of the PsA-PsC association test identified enrichment of vitamin digestion and absorption pathway in PsC (P = 1.3 × 10^-4). Correlation network analyses elucidated that a subnetwork centered on aspartate was constructed among the psoriasis-associated metabolites; meanwhile, the major subnetwork among metabolites with differences between PsA and PsC was primarily formed from saturated fatty acids.

CONCLUSION

Our large-scale metabolome analysis highlights novel characteristics of plasma metabolites in psoriasis and the differences between PsA and PsC, which could be used as potential biomarkers of psoriasis and its clinical subtypes. These findings contribute to our understanding of psoriasis pathophysiology.

Multiomics Analysis and Systems Biology Integration Identifies the Roles of IL-9 in Keratinocyte Metabolic Reprogramming

IL-9‒producing T cells are present in healthy skin as well as in the cutaneous lesions of inflammatory diseases and cancers. However, the roles of IL-9 in human skin during homeostasis and in the pathogenesis of inflammatory disorders remain obscure. In this study, we examined the roles of IL-9 in metabolic reprogramming of human primary keratinocytes (KCs). High-throughput quantitative proteomics revealed that IL-9 signaling in human primary KCs disrupts the electron transport chain by downregulating multiple electron transport chain proteins. Nuclear magnetic resonance-based metabolomics showed that IL-9 also reduced the production of tricarboxylic acid cycle intermediates in human primary KCs. An integration of multiomics data with systems-level analysis using the constraint-based MitoCore model predicted marked IL-9-dependent effects on central carbohydrate metabolism, particularly in relation to the glycolytic switch. Stable isotope metabolomics and biochemical assays confirmed increased glucose consumption and redirection of metabolic flux toward lactate by IL-9. Functionally, IL-9 inhibited ROS production by IFN-γ and promoted human primary KC survival by inhibiting apoptosis. In conclusion, our data reveal IL-9 as a master regulator of KC metabolic reprogramming and survival.

Glyoxalase System in the Progression of Skin Aging and Skin Malignancies

Dicarbonyl compounds, including methylglyoxal (MGO) and glyoxal (GO), are mainly formed as byproducts of glucose metabolism. The main glyoxalase system consists of glyoxalase I and II (Glo1 and Glo2) and is the main enzyme involved in the detoxification of dicarbonyl stress, which occurs as an accumulation of MGO or GO due to decreased activity or expression of Glo1. Dicarbonyl stress is a major cause of cellular and tissue dysfunction that causes various health issues, including diabetes, aging, and cancer. The skin is the largest organ in the body. In this review, we discuss the role of the glyoxalase system in the progression of skin aging, and more importantly, skin malignancies. We also discuss the future prospects of the glyoxalase system in other skin abnormalities such as psoriasis and vitiligo, including hyperpigmentation. Finally, in the present review, we suggest the role of glyoxalase in the progression of skin aging and glyoxalase system as a potential target for anticancer drug development for skin cancer.

The versatility of azelaic acid in dermatology

Azelaic acid has numerous pharmacological uses in dermatology. Its anti-inflammatory and anti-oxidant properties are thought to correlate with its efficacy in papulopustular rosacea and acne vulgaris, amongst other cutaneous conditions. We conducted a review of the literature on the use of azelaic acid in dermatology using key terms 'acne', 'azelaic acid', 'dermatology', 'melasma', 'rosacea', searching databases such as MEDLINE, EMBASE and PubMed. Only articles in English were chosen. The level of evidence was evaluated and selected accordingly listing the studies with the highest level of evidence first using the Oxford Center of Evidence-Based Medicine 2011 guidance.This review found the strongest evidence supporting the use of azelaic acid in rosacea, followed by its use off-label in melasma followed by acne vulgaris. Weaker evidence is currently available to support the use of azelaic acid in several other conditions such as hidradenitis suppurativa, keratosis pilaris and male androgenic alopecia.Azelaic acid, as a monotherapy or in combination, could be an effective first-line or alternative treatment, which is well-tolerated and safe for a range of dermatological conditions.

(R)-Salbutamol Improves Imiquimod-Induced Psoriasis-Like Skin Dermatitis by Regulating the Th17/Tregs Balance and Glycerophospholipid Metabolism

Psoriasis is a skin disease that is characterized by a high degree of inflammation caused by immune dysfunction. (R)-salbutamol is a bronchodilator for asthma and was reported to alleviate immune system reactions in several diseases. In this study, using imiquimod (IMQ)-induced mouse psoriasis-like dermatitis model, we evaluated the therapeutic effects of (R)-salbutamol in psoriasis in vivo, and explored the metabolic pathway involved. The results showed that, compared with IMQ group, (R)-salbutamol treatment significantly ameliorated psoriasis, reversed the suppressive effects of IMQ on differentiation, extreme keratinocyte proliferation, and infiltration of inflammatory cells. Enzyme-linked immunosorbent assays (ELISA) showed that (R)-salbutamol markedly reduced the plasma levels of IL-17. Cell analysis using flow cytometry showed that (R)-salbutamol decreased the proportion of CD4+ Th17+ T cells (Th17), whereas it increased the percentage of CD25+ Foxp3+ regulatory T cells (Tregs) in the spleens. (R)-salbutamol also decreased the weight ratio of spleen to body. Furthermore, untargeted metabolomics showed that (R)-salbutamol affected three metabolic pathways, including (i) arachidonic acid metabolism, (ii) sphingolipid metabolism, and (iii) glycerophospholipid metabolism. These results demonstrated that (R)-salbutamol can alleviate IMQ-induced psoriasis through regulating Th17/Tregs cell response and glycerophospholipid metabolism. It may provide a new use of (R)-salbutamol in the management of psoriasis.