Regulation of inflammation by the antioxidant haem oxygenase 1.

Haem oxygenase 1 (HO-1), an inducible enzyme responsible for the breakdown of haem, is primarily considered an antioxidant, and has long been overlooked by immunologists. However, research over the past two decades in particular has demonstrated that HO-1 also exhibits numerous anti-inflammatory properties. These emerging immunomodulatory functions have made HO-1 an appealing target for treatment of diseases characterized by high levels of chronic inflammation. In this Review, we present an introduction to HO-1 for immunologists, including an overview of its roles in iron metabolism and antioxidant defence, and the factors which regulate its expression. We discuss the impact of HO-1 induction in specific immune cell populations and provide new insights into the immunomodulation that accompanies haem catabolism, including its relationship to immunometabolism. Furthermore, we highlight the therapeutic potential of HO-1 induction to treat chronic inflammatory and autoimmune diseases, and the issues faced when trying to translate such therapies to the clinic. Finally, we examine a number of alternative, safer strategies that are under investigation to harness the therapeutic potential of HO-1, including the use of phytochemicals, novel HO-1 inducers and carbon monoxide-based therapies.

The role of Dipeptidyl Peptidase-4 in cutaneous disease.

Dipeptidyl peptidase-4 (DPP4) is a multifunctional, transmembrane glycoprotein present on the cell surface of various tissues. It is present in multiple molecular forms including cell surface and soluble. The role of DPP4 and its inhibition in cutaneous dermatoses have been a recent point of investigation. DPP4 exerts a notable influence on T-cell biology, the induction of skin-specific lymphocytes, and the homeostasis between regulatory and effector T cells. Moreover, DPP4 interacts with a broad range of molecules, including adenosine deaminase, caveolin-1, CXCR4 receptor, M6P/insulin-like growth factor II-receptor and fibroblast activation protein-α, triggering downstream effects that modulate the immune response, cell adhesion and chemokine activity. DPP4 expression on melanocytes, keratinocytes and fibroblasts further alters cell function and, thus, has crucial implications in cutaneous pathology. As a result, DPP4 plays a significant role in bullous pemphigoid, T helper type 1-like reactions, cutaneous lymphoma, melanoma, wound healing and fibrotic disorders. This review illustrates the multifactorial role of DPP4 expression, regulation, and inhibition in cutaneous diseases.

Cimifugin ameliorates imiquimod-induced psoriasis by inhibiting oxidative stress and inflammation via NF-κB/MAPK pathway.

Cimifugin is an important component of chromones in the dry roots of Saposhikovia divaricata for treating inflammatory diseases. However, the possible effect of cimifugin in psoriasis needs further investigation. This current work was designed to evaluate the effects of cimifugin in psoriasis in vivo and in vitro, and unravel the underlying molecular mechanism. Here, we used imiquimod (IMQ) or tumor necrosis factor (TNF)-α to induce a psoriasis-like model in mice or keratinocytes. Obviously, the results showed that cimifugin reduced epidermal hyperplasia, psoriasis area severity index (PASI) scores, ear thickness and histological psoriasiform lesions in IMQ-induced mice. The decreased levels of reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT), and the accumulation of malondialdehyde (MDA) in skin tissues by IMQ were attenuated by cimifugin. Furthermore, it was observed that cimifugin effectively reversed IMQ-induced up-regulation of proinflammatory cytokines, including TNF-α, IL-6, IL-1ß, IL-17A, and IL-22. Mechanically, we noticed that cimifugin inhibited IMQ-activated phosphorylation of NF-κB (IκB and p65) and MAPK (JNK, ERK, and p38) signaling pathways. Similar alterations for oxidative stress and inflammation parameters were also detected in TNF-α-treated HaCaT cells. In addition, cimifugin-induced down-regulation of ICAM-1 were observed in TNF-α-treated cells. Altogether, our findings suggest that cimifugin protects against oxidative stress and inflammation in psoriasis-like pathogenesis by inactivating NF-κB/MAPK signaling pathway, which may develop a novel and effective drug for the therapy of psoriasis.

JNK1 Signaling Downstream of the EGFR Pathway Contributes to Aldara®-Induced Skin Inflammation.

c-Jun N-terminal protein kinase 1 (JNK1) is involved in multiple biological processes but its implication in inflammatory skin diseases is still poorly defined. Herein, we studied the role of JNK1 in the context of Aldara®-induced skin inflammation. We observed that constitutive ablation of JNK1 reduced Aldara®-induced acanthosis and expression of inflammatory markers. Conditional deletion of JNK1 in myeloid cells led to reduced skin inflammation, a finding that was associated with impaired Aldara®-induced inflammasome activation in vitro. Next, we evaluated the specific role of JNK1 in epidermal cells. We observed reduced Aldara®-induced acanthosis despite similar levels of inflammatory markers. Transcriptomic and epigenomic analysis of keratinocytes revealed the potential involvement of JNK1 in the EGFR signaling pathway. Finally, we show that inhibition of the EGFR pathway reduced Aldara®-induced acanthosis. Taken together, these data indicate that JNK1 plays a dual role in the context of psoriasis by regulating the production of inflammatory cytokines by myeloid cells and the sensitivity of keratinocytes to EGFR ligands. These results suggest that JNK1 could represent a valuable therapeutic target in the context of psoriasis.

Zdhhc2 Is Essential for Plasmacytoid Dendritic Cells Mediated Inflammatory Response in Psoriasis.

Zdhhc family genes are composed of 24 members that regulate palmitoylation, a post-translational modification process for proteins. Mutations in genes that alter palmitoylation or de-palmitoylation could result in neurodegenerative diseases and inflammatory disorders. In this study, we found that Zdhhc2 was robustly induced in psoriatic skin and loss of Zdhhc2 in mice by CRISPR/Cas9 dramatically inhibited pathology of the ear skin following imiquimod treatment. As psoriasis is an inflammatory disorder, we analyzed tissue infiltrating immune cells and cytokine production. Strikingly we found that a master psoriatic cytokine interferon-α (IFN-α) in the lesioned skin of wildtype (WT) mice was 23-fold higher than that in Zdhhc2 deficient counterparts. In addition, we found that CD45+ white blood cells (WBC) infiltrating in the skin of Zdhhc2 deficient mice were also significantly reduced. Amelioration in psoriasis and dramatically reduced inflammation of Zdhhc2 deficient mice led us to analyze the cellular components that were affected by loss of Zdhhc2. We found that imiquimod induced plasmacytoid dendritic cell (pDC) accumulation in psoriatic skin, spleen, and draining lymph nodes (DLN) were drastically decreased in Zdhhc2 deficient mice, and the expression of pDC activation marker CD80 also exhibited significantly inhibited in psoriatic skin. In further experiments, we confirmed the cell intrinsic effect of Zdhhc2 on pDCs as we found that loss of zDHHC2 in human CAL-1 pDC dampened both interferon regulatory factor 7 (IRF7) phosphorylation and IFN-α production. Therefore, we identified novel function of Zdhhc2 in controlling inflammatory response in psoriasis in mice and we also confirmed that crucial role of Zdhhc2 in pDCs by regulating IRF7 activity and production of the critical cytokine. Our results finding the dependence of IFN-α production on Zdhhc2 in inflamed murine skin and in human pDCs provide rationale for targeting this new molecule in treatment of inflammation.

The Proteomic Profile of Keratinocytes and Lymphocytes in Psoriatic Patients.

PURPOSE: Psoriatic skin lesions are associated with chronic inflammation related to immune cell activity. Therefore, the aim of this study is to compare changes in the proteome of psoriatic keratinocytes and lymphocytes. EXPERIMENTAL DESIGN: A proteomics approach is used to analyze the expression of proteins in keratinocytes and lymphocytes from psoriatic patients and healthy controls. RESULTS: As a result 2119 proteins for keratinocytes and 1235 proteins for lymphocytes are identified. Psoriatic keratinocytes has 68 downregulated and 7 upregulated proteins and psoriatic lymphocytes has 106 downregulated and 67 upregulated proteins compared to healthy individuals. The list of downregulated proteins includes proteins involved in antioxidant homeostasis and, transcription regulation; upregulated proteins are involved in glycolytic processes and translation. These changes are accompanied by an increased level of 4-Hydroxynonenal-protein adducts; control cells are characterized by 4-Hydroxynonenal-Lysine adducts formed with structural and binding proteins, while in psoriatic cells 4-Hydroxynonenal-Lysine, 4-Hydroxynonenal-Histidine, and 4-Hydroxynonenal-Cysteine adducts with various molecular function proteins occur. CONCLUSIONS AND CLINICAL RELEVANCE: This study highlights the changes in psoriatic keratinocytes and lymphocytes that can be directly involved in the development of psoriasis. In both cell types the most significant changes are associated with upregulation of phosphoglycerate mutase 1 and downregulation of thioredoxin reductase.

Paraoxonases and psoriasis: negative imbalance of antioxidant endogenous mechanisms.

BACKGROUND: Numerous reports have shown that psoriasis patients are more exposed to lipoprotein peroxidation and to a decrease in the activity of paraoxonase (PON)1, an antioxidant and anti-inflammatory enzyme. Thus, it has been suggested that malfunction of the antioxidant system and an increased production of reactive oxygen species drive immune inflammatory events, that result in progressive skin cell damage in patients with psoriasis. The PON protein family, including PON1, PON2 and PON3, is one of the most important endogenous defense mechanisms against oxidative stress. In the present study, we investigated PON gene expression in psoriasis and in cutaneous oxidative stress. METHODS: The study population included 10 patients affected by moderate-to-severe plaque psoriasis and 15 healthy donors who have undergone to plastic surgery, were used as control. Skin punch biopsies of lesional and non lesional psoriatic skin were performed for analysis of PON2 and PON3 gene expression. In addition, oxidation assays in ex vivo full-thickness healthy skin organ cultures were performed. RESULTS: No significant differences were observed between PON2 and PON3 gene expression in psoriatic lesional and non lesional skin compared with healthy controls. H2O2 treatment induced a significant decrease of PON2 and PON3 expression in ex vivo full-thickness healthy skin organ cultures; conversely the pretreatment of samples with the antioxidant reagent N-acetyl-L-cysteine (NAC) induced a significant increase. Interestingly, no significant alterations were reported for PON2 and PON3 expression in ex vivo full-thickness healthy skin organ cultures stimulated with IL-17. CONCLUSIONS: Taken together our findings have revealed that a strong pro-oxidative activity is not effectively countered by antioxidant endogenous mechanisms both in psoriatic skin and in ex vivo experimental model.

Heme oxygenase and iron status in exosomes of psoriasis patients.

Psoriasis is an autoimmune skin disease characterized by hyperproliferation of keratinocytes due to interplay between keratinocytes and immune cells. Iron status plays an important role in modifying the function of the immune system. Heme oxygenase (HO), heme-degrading enzyme, plays important role in protective response to oxidative cellular stress. We aimed in this study to map the iron status and HO levels and declare the role HO enzyme in iron homeostasis and immune-modulation in psoriasis. Fifty-one patients with psoriasis and 50 age- and sex-matched healthy controls were enrolled in this study. 5 mL blood sample was withdrawn from each subject. Hepcidin, iron soluble transferring receptor (sTfR), and total iron binding capacity (TIBC) were estimated using ELISA technique and, HO-1 gene level was detected using RT-PCR (reverse transcription-polymerase chain reaction). Iron levels, TIBC, and hepcidin were significantly lower in cases compared to controls. On the contrary, sTfR and HO-1 were significantly over-expressed in cases compared to controls (p < 0.05 in all). HO-1 expression negatively correlated with PASI score and disease extent (%) (r = - 0.614-, p = 0.001; r = - 0.807-, p = 0.001 respectively). There were no significant associations between HO-1 expression and iron, TIBC, hepcidin, sTfR levels (p > 0.05 in all). Iron supplements for the patients with psoriasis are important to maintain haematopoiesis. The induction of HO-1 might have be a promising approach for the treatment of psoriasis through antioxidant ability, immunomodulatory role as well as its role in heme synthesis.

Naturally derived Heme-Oxygenase 1 inducers attenuate inflammatory responses in human dendritic cells and T cells: relevance for psoriasis treatment.

Psoriasis is a chronic autoimmune disease mediated by dysregulated immune responses in dendritic cells (DC) and T cells. The stress-response enzyme heme oxygenase-1 (HO-1) has been described as protective in animal models of psoriasis, however, implementation of HO-1-based therapies is hindered by the lack of clinically-suitable HO-1 inducers. The plant-derived polyphenols, carnosol and curcumin, have been identified as candidate HO-1 inducers however there has been little investigation into their effects on human immune cells. We demonstrate that treatment of human DC with these polyphenols limits DC maturation, reduces pro-inflammatory cytokine production, and prevents induction of allospecific T cell responses, in a manner partially dependent on carbon monoxide (CO). We also characterised their effects in ex-vivo psoriasis PBMC and report that curcumin, but not carnosol, strongly reduces T cell proliferation and cytokine poly-functionality, with reduced expression of psoriatic cytokines IFNγ, IL-17, GM-CSF and IL-22. This study therefore supports reports highlighting the therapeutic potential of curcumin in psoriasis by providing insight into its immunological effects on healthy human DC and psoriasis PBMC. We also demonstrate, for the first time, the anti-inflammatory effects of carnosol in human immune cells.

MAPK Phosphatase-1 Deficiency Exacerbates the Severity of Imiquimod-Induced Psoriasiform Skin Disease.

Persistent activation of mitogen-activated protein kinase (MAPK) is believed to be involved in psoriasis pathogenesis. MAPK phosphatase-1 (MKP-1) is an important negative regulator of MAPK activity, but the cellular and molecular mechanisms of MKP-1 in psoriasis development are largely unknown. In this study, we found that the expression of MKP-1 was decreased in the imiquimod (IMQ)-induced psoriasiform mouse skin. MKP-1-deficient (MKP-1-/-) mice were highly susceptible to IMQ-induced skin inflammation, which was associated with increased production of inflammatory cytokines and chemokines. MKP-1 acted on both hematopoietic and non-hematopoietic cells to regulate psoriasis pathogenesis. MKP-1 deficiency in macrophages led to enhanced p38 activation and higher expression of interleukin (IL)-1ß, CXCL2, and S100a8 upon R848 stimulation. Moreover, MKP-1 deficiency in the non-hematopoietic compartments led to an enhanced IL-22 receptor signaling and higher expression of CXCL1 and CXCL2 upon IMQ treatment. Collectively, our data suggest a critical role for MKP-1 in the regulation of skin inflammation.

Correlation of High-Density Lipoprotein-Associated Paraoxonase 1 Activity With Systemic Inflammation, Disease Activity, and Cardiovascular Risk Factors in Psoriatic Disease.

OBJECTIVE: To compare the activity of high-density lipoprotein (HDL)-associated paraoxonase 1 (PON1) in patients with psoriasis (PsO) and patients with psoriatic arthritis (PsA), and to evaluate the association of PON1 activity with the extent of disease activity and severity of the cardiovascular disease (CVD) burden in these patients. METHODS: Serum levels of paraoxonase and arylesterase activity (both measures of PON1 function in humans) were measured in patients with PsA (n = 198, 51.0% male) and patients with PsO (n = 145, 50.3% male) who were enrolled in a longitudinal psoriatic disease biorepository. Data on PsA disease activity (using the Disease Activity Score in 28 joints [DAS28], Clinical Disease Activity Index, and painful/swollen joint counts), preexistent CVD and CVD risk factors (including diabetes, dyslipidemia, hypertension, and smoking), Framingham Risk Scores for CVD, quality of life measures, and laboratory test findings (erythrocyte sedimentation rate, C-reactive protein level, and lipid profiles) were recorded. RESULTS: Serum arylesterase activities were significantly lower in patients with PsO and patients with PsA (mean ± SD 111.1 ± 25.5 µmoles/minute/ml and 124.4 ± 33.4 µmoles/minute/ml, respectively) compared to healthy controls (144.3 ± 33.4 µmoles/minute/ml) (each P < 0.001 versus healthy controls). Serum arylesterase activity decreased in parallel with increasing levels of disease activity (DAS28 scores, P = 0.012), older age (P = 0.013), higher body mass index (P = 0.042), greater incidence of metabolic syndrome (P = 0.004) and hypertension (P = 0.014), and worsening Framingham Risk Scores (P = 0.001). However, no correlation was seen between serum arylesterase activity and the extent of disease activity or CVD burden in patients with PsO. Serum paraoxonase activity trended lower both in patients with PsO and in patients with PsA (each P = 0.073 versus healthy controls). However, no association was seen between serum paraoxonase activity and the extent of disease activity or CVD burden in either of the patient cohorts. CONCLUSION: PON1 activity is decreased in psoriatic diseases. In the PsA cohort, decreases in arylesterase activity correlated with increasing severity of joint disease and CVD burden. Arylesterase activity, as compared to paraoxonase activity, appeared to serve as a more sensitive predictor of preexisting CV risk factors in the PsA cohort. However, this correlation was not observed in the PsO population.

A possible role for CD26/DPPIV enzyme activity in the regulation of psoriatic pruritus.

BACKGROUND: Psoriasis (PSO) is one of the most common chronic inflammatory skin diseases, and pruritus affects approximately 60-90% of patients with PSO. However, the pathogenesis of pruritus in PSO remains unclear. Dipeptidyl peptidase IV (DPPIV) enzyme activity is involved in the regulation of peptide hormones, chemokines and neurotransmitters. OBJECTIVES: Our aim is to evaluate for a potential association between DPPIV and an increased risk of pruritus, and to identify possible underlying treatment targets in affected patients. METHODS: Utilizing clinical serum samples of PSO patients and in vivo experimental pruritus models, we evaluated for a potential association between DPPIV and an increased risk for pruritus, and attempted to identify possible underlying treatment targets in pruritus of PSO. RESULTS: We first showed that levels of DPPIV enzyme activity in sera of patients with PSO were significantly increased compared to those of healthy controls. We next evaluated levels of substance-P (SP), which is a neurotransmitter for pruritus and a substrate for DPPIV enzyme. Truncated form SP cleaved by DPPIV was significantly increased in sera of PSO. In an in vivo pruritus model induced by SP, scratching was decreased by treatment with a DPPIV inhibitor. Moreover, DPPIV-knockout mice showed attenuation of scratching induced by SP. Finally, scratching was decreased following the administration of a DPPIV inhibitor in an imiquimod-induced PSO model. On the other hand, scratching induced by imiquimod was increased in DPPIV overexpressing-mice. CONCLUSIONS: These results suggest that inhibition of DPPIV enzyme activity regulates pruritus in PSO.

Identification of novel TACE inhibitors compatible with topical application.

Targeting the Tumor Necrosis Factor α signalling with antibodies has led to a revolution in the treatment of psoriasis. Locally inhibiting Tumor Necrosis Factor α Converting Enzyme (TACE or ADAM17) could potentially mimic those effects and help treat mild to moderate psoriasis, without the reported side effect of systemic TACE inhibitors. Efforts to identify new TACE inhibitors are presented here. Enzymatic SAR as well as ADME and physico-chemistry data are presented. This study culminated in the identification of potent enzymatic inhibitors. Suboptimal cellular activity of this series is discussed in the context of previously published results.

Cathepsin S is the major activator of the psoriasis-associated proinflammatory cytokine IL-36γ.

The proinflammatory cytokine IL-36γ is highly expressed in epithelial cells and is a pivotal mediator of epithelial inflammation. In particular, IL-36γ is strongly associated with the inflammatory skin disease psoriasis. As with other IL-1 cytokines, IL-36γ is expressed as an inactive precursor and must be processed by specific proteases to become bioactive. Our aim therefore was to identify protease/s capable of IL-36γ activation and explore the importance of this activation in psoriasis. Using a keratinocyte-based activity assay in conjunction with small-molecule inhibitors and siRNA gene silencing, cathepsin S was identified as the major IL-36γ-activating protease expressed by epithelial cells. Interestingly, cathepsin S activity was strongly up-regulated in samples extracted from psoriasis patients relative to healthy controls. In addition, IL-36γ-Ser18, identified as the main product of cathepsin S-dependent IL-36γ cleavage, induced psoriasiform changes in human skin-equivalent models. Together, these data provide important mechanistic insights into the activation of IL-36γ and highlight that cathepsin S-mediated activation of IL-36γ may be important in the development of numerous IL-36γ-driven pathologies, in addition to psoriasis.

Janus kinase inhibitors in dermatology: A systematic review.

BACKGROUND: Janus kinase (JAK) inhibitors are emerging as a promising new treatment modality for many inflammatory conditions. OBJECTIVE: Our aim was to systematically review the available data on the use of JAK inhibitors in cutaneous diseases. METHODS: This is a systematic review of PubMed and ClinicalTrials.gov. RESULTS: One hundred thirty-four articles matched our search terms, of which 78 were original articles and 12 reports on adverse events. Eighteen clinical trials were found. JAK inhibitors have been extensively studied for psoriasis, showing beneficial results that were comparable to the effects achieved by etanercept. Favorable results were also observed for alopecia areata. Promising preliminary results were reported for vitiligo, dermatitis, graft versus host disease, cutaneous T cell lymphoma, and lupus erythematosus. The most common adverse events reported were infections, mostly nasopharyngitis and upper respiratory tract infections. LIMITATIONS: It was not possible to perform a meta-analysis of the results. CONCLUSIONS: This systematic review shows that while JAK inhibitors hold promise for many skin disorders, there are still gaps regarding the correct dosing and safety profile of these medications for dermatologic indications. Additional trials are necessary to address these gaps.

An investigation of cytochrome p450 (CYP) and glutathione S-transferase (GST) isoenzyme protein expression and related interactions with phototherapy in patients with psoriasis vulgaris.

Oxidative stress may play an important role in the pathogenesis of psoriasis. Glutathione S-transferases (GSTs) make up a group of antioxidant enzymes. Cytochrome p450 (CYP) enzymes can influence oxidation and reduction reactions. We investigated the potential effects of GST and CYP enzymes in the pathogenesis of psoriasis. The study included 32 psoriasis patients and 22 healthy subjects. Psoriasis patients were administered 20 sessions of narrowband ultraviolet B phototherapy. Expressions of GST and CYP enzymes were assessed by immunohistochemical staining. Expression levels of GSTK1, GSTM1, and GSTT1 were significantly higher in psoriasis than in control tissues (P = 0.022, P = 0.001, and P = 0.006, respectively). Pre- and post-treatment expression was similar. Expression of CYP1A1 and CYP2E1 was significantly higher in pre- (P = 0.003 and P = 0.001, respectively) and post-treatment (P = 0.003 and P = 0.001, respectively) psoriatic tissues than in control tissues. No significant differences in CYP1B1 levels between the study and control groups were detected before treatment (P > 0.05). However, CYP1B1 levels were higher in post-treatment psoriatic tissue than in control tissue (P = 0.045). The significant increases in expression of GSTK1, GSTM1, and GSTT1 in psoriasis may reflect the increased activation of GST in response to excessive free radical formation from activated neutrophils or ultraviolet exposure to maintain antioxidant capacity in psoriasis. Furthermore, expressions of CYP1A1 and CYP2E1 represent important enzymatic systems in psoriasis. These findings suggest that psoriasis is an oxidative stress condition, although phototherapy does not affect these enzymatic systems. Further investigation is required.

Immune cells from patients with psoriasis are defective in inducing indoleamine 2,3-dioxygenase expression in response to inflammatory stimuli.

BACKGROUND: Indoleamine 2,3-dioxygenase (IDO) is an inducible enzyme that suppresses the immune response. The role of IDO as a negative regulator of inflammatory responses has been documented in several experimental autoimmune diseases. OBJECTIVES: To explore the regulation of IDO by immune cells in psoriasis and its relation with disease severity. METHODS: The expression and activity of IDO were assessed by reverse-transcriptase polymerase chain reaction, flow cytometry and high-performance liquid chromatography in peripheral blood of patients with moderate-to-severe plaque-type psoriasis. The ability of immune cells to express IDO in response to inflammatory stimuli was studied. The functional role of IDO expression was evaluated in a regulatory T cell (Treg) differentiation assay, using cocultures of immature monocyte-derived dendritic cells with autologous peripheral CD4+ T cells. RESULTS: Analysis of the kynurenine-to-tryptophan ratio in serum samples indicated higher IDO activity in patients with psoriasis than in healthy controls. However, correlation studies showed lower IDO activity in those patients with higher Psoriasis Area and Severity Index (PASI). Although myeloid dendritic cells from patients with psoriasis expressed higher levels of IDO than those from healthy controls, these cells did not upregulate IDO in response to a combination of tumour necrosis factor-α, interleukin (IL)-1ß and IL-6 cytokines. The defective expression of IDO correlated with PASI. Immature monocyte-derived dendritic cells from patients with psoriasis also expressed low levels of IDO and induced CD4+ Treg differentiation poorly. CONCLUSIONS: Immune cells from patients with psoriasis have a defect in upregulating IDO in response to inflammation associated with the severity of psoriasis.

Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism in psoriasis in southern Turkey

Abstract: Background: Psoriasis is a multigenic and multifactorial dermatological disease linked to cardiovascular diseases. Increased levels of homocysteine in patients with psoriasis have been demonstrated in many studies. The most frequently investigated genetic defect that plays a role in homocysteine metabolism is single point substitution (C to T) located on the 677th nucleotide of the methylenetetrahydrofolate reductase gene (MTHFR). Objective: In this study, we aimed to investigate methylenetetrahydrofolate C677T polymorphism in psoriasis patients in Turkey. Methods: The study included 96 patients with psoriasis and 77 controls from southern Turkey. Methylenetetrahydrofolate C677T polymorphism was analysed using the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism methods. Results: In the psoriasis group, 34 CC (35.4%), 46 CT (47.9%) and 16 TT (16.7%) genotypes were found, respectively; while in the control group, the figures were 39 (50.6%), 35 (45.5%), 3 (3.9%). Homozygote and heterozygote T alleles of methylenetetrahydrofolate C677T polymorphism were significantly higher in the psoriasis than in the control group (p=0.013). Conclusion: We firstly found a correlation between methylenetetrahydrofolate C677T polymorphism and psoriasis among the southern Turkish population.

Expression and Function of Group IIE Phospholipase A2 in Mouse Skin.

Recent studies using knock-out mice for various secreted phospholipase A2 (sPLA2) isoforms have revealed their non-redundant roles in diverse biological events. In the skin, group IIF sPLA2 (sPLA2-IIF), an "epidermal sPLA2" expressed in the suprabasal keratinocytes, plays a fundamental role in epidermal-hyperplasic diseases such as psoriasis and skin cancer. In this study, we found that group IIE sPLA2 (sPLA2-IIE) was expressed abundantly in hair follicles and to a lesser extent in basal epidermal keratinocytes in mouse skin. Mice lacking sPLA2-IIE exhibited skin abnormalities distinct from those in mice lacking sPLA2-IIF, with perturbation of hair follicle ultrastructure, modest changes in the steady-state expression of a subset of skin genes, and no changes in the features of psoriasis or contact dermatitis. Lipidomics analysis revealed that sPLA2-IIE and -IIF were coupled with distinct lipid pathways in the skin. Overall, two skin sPLA2s, hair follicular sPLA2-IIE and epidermal sPLA2-IIF, play non-redundant roles in distinct compartments of mouse skin, underscoring the functional diversity of multiple sPLA2s in the coordinated regulation of skin homeostasis and diseases.