Heme oxygenase 1 attenuates the development of atopic dermatitis–like lesions in mice: Implications for human disease

Periostin C-Terminal Is Intrinsically Disordered and Interacts with 143 Proteins in an In Vitro Epidermal Model of Atopic Dermatitis

Human periostin is a 78-91 kDa matricellular protein implicated in extracellular matrix remodeling, tumor development, metastasis, and inflammatory diseases like atopic dermatitis, psoriasis, and asthma. The protein consists of six domains, including an N-terminal Cys-rich CROPT domain, four fasciclin-1 domains, and a C-terminal domain. The exons encoding the C-terminal domain may be alternatively spliced by shuffling four exons, generating ten variants of unknown function. Here, we investigate the structure and interactome of the full-length variant of the C-terminal domain with no exons spliced out. The structural analysis showed that the C-terminal domain lacked a tertiary structure and was intrinsically disordered. In addition, we show that the motif responsible for heparin-binding is in the conserved very C-terminal part of periostin. Pull-down confirmed three known interaction partners and identified an additional 140 proteins, among which nine previously have been implicated in atopic dermatitis. Based on our findings, we suggest that the C-terminal domain of periostin facilitates interactions between connective tissue components in concert with the four fasciclin domains.

Veronica persica Ethanol Extract Ameliorates Dinitrochlorobenzene-Induced Atopic Dermatitis-like Skin Inflammation in Mice, Likely by Inducing Nrf2/HO-1 Signaling

Atopic dermatitis (AD) is chronic allergic contact dermatitis with immune dysregulation. Veronica persica has pharmacological activity that prevents asthmatic inflammation by ameliorating inflammatory cell activation. However, the potential effects of the ethanol extract of V. persica (EEVP) on AD remain elusive. This study evaluated the activity and underlying molecular pathway of EEVP in two AD models: dinitrochlorobenzene (DNCB)-induced mice and interferon (IFN)-γ/tumor necrosis factor (TNF)-α-stimulated human HaCaT keratinocytes. EEVP attenuated the DNCB-induced increase in serum immunoglobulin E and histamine levels, mast cell counts in toluidine-blue-stained dorsal skin, inflammatory cytokine (IFN-γ, interleukin [IL]-4, IL-5, and IL-13) levels in cultured splenocytes, and the mRNA expression of IL6, IL13, IL31 receptor, CCR-3, and TNFα in dorsal tissue. Additionally, EEVP inhibited the IFN-γ/TNF-α-induced mRNA expression of IL6, IL13, and CXCL10 in HaCaT cells. Furthermore, EEVP restored the IFN-γ/TNF-α-induced downregulation of heme oxygenase (HO)-1 in HaCaT cells by inducing nuclear factor erythroid 2-related factor 2 (Nrf2) expression. A molecular docking analysis demonstrated that EEVP components have a strong affinity to the Kelch-like ECH-associated protein 1 Kelch domain. In summary, EEVP inhibits inflammatory AD by attenuating immune cell activation and inducing the Nrf2/HO-1 signaling pathway in skin keratinocytes.

Impaired expression of metallothioneins contributes to allergen-induced inflammation in patients with atopic dermatitis

Regulation of cutaneous immunity is severely compromised in inflammatory skin disease. To investigate the molecular crosstalk underpinning tolerance versus inflammation in atopic dermatitis, we utilise a human in vivo allergen challenge study, exposing atopic dermatitis patients to house dust mite. Here we analyse transcriptional programmes at the population and single cell levels in parallel with immunophenotyping of cutaneous immunocytes revealed a distinct dichotomy in atopic dermatitis patient responsiveness to house dust mite challenge. Our study shows that reactivity to house dust mite was associated with high basal levels of TNF-expressing cutaneous Th17 T cells, and documents the presence of hub structures where Langerhans cells and T cells co-localised. Mechanistically, we identify expression of metallothioneins and transcriptional programmes encoding antioxidant defences across all skin cell types, that appear to protect against allergen-induced inflammation. Furthermore, single nucleotide polymorphisms in the MTIX gene are associated with patients who did not react to house dust mite, opening up possibilities for therapeutic interventions modulating metallothionein expression in atopic dermatitis.

Heme Oxygenase-1 Is Upregulated during Differentiation of Keratinocytes but Its Expression Is Dispensable for Cornification of Murine Epidermis

The epidermal barrier of mammals is initially formed during embryonic development and continuously regenerated by the differentiation and cornification of keratinocytes in postnatal life. Cornification is associated with the breakdown of organelles and other cell components by mechanisms which are only incompletely understood. Here, we investigated whether heme oxygenase 1 (HO-1), which converts heme into biliverdin, ferrous iron and carbon monoxide, is required for normal cornification of epidermal keratinocytes. We show that HO-1 is transcriptionally upregulated during the terminal differentiation of human keratinocytes in vitro and in vivo. Immunohistochemistry demonstrated expression of HO-1 in the granular layer of the epidermis where keratinocytes undergo cornification. Next, we deleted the Hmox1 gene, which encodes HO-1, by crossing Hmox1-floxed and K14-Cre mice. The epidermis and isolated keratinocytes of the resulting Hmox1f/f K14-Cre mice lacked HO-1 expression. The genetic inactivation of HO-1 did not impair the expression of keratinocyte differentiation markers, loricrin and filaggrin. Likewise, the transglutaminase activity and formation of the stratum corneum were not altered in Hmox1f/f K14-Cre mice, suggesting that HO-1 is dispensable for epidermal cornification. The genetically modified mice generated in this study may be useful for future investigations of the potential roles of epidermal HO-1 in iron metabolism and responses to oxidative stress.

Lymphocyte Expression of Intracellular Cytokines and Heat Shock Proteins in Peripheral Blood of Patients with Atopic Dermatitis

INTRODUCTION

The present study evaluates expression by activated CD4+ T helper1 (Th1) and T helper 2 (Th2) T lymphocytes of pro-inflammatory cytokines and cytoprotective heat shock proteins (HSPs) in peripheral blood of atopic dermatitis (AD) patients.

METHODS

This research represents preliminary work by the authors to identify correlates between critical immune parameters with the potential to serve as guidelines for the development of pharmacological strategies for altering these factors to promote the restoration of healthy immune profiles in persons afflicted with major atopic diseases. The major experimental strategy used in this research assessed immune activation by peripheral blood mononuclear cells (PBMC) from 21 AD patients and 12 age- and gender-matched healthy control subjects cultured with phorbol myristate acetate (PMA) and ionomycin (PMA/I), which are mutagenic immune activators, to induce expression of pro-inflammatory biomarkers in CD4+ T cells differentiated to express Th1 or Th2 cytokines and heme oxygenase-1 (HO-1) intracellularly (i). Evaluations were performed using an FC500 Beckman-Coulter flow cytometer. Elevated CD4+ T cell expression of cytokines, interleukin-4 (iIL-4), interleukin- 5 (iIL-5), interleukin-10 (iIL-10), interferon-gamma (iIFN-g), tumor necrosis factor-alpha (iTNF-α), were observed.

RESULTS

Additionally, the heat shock proteins (HSP) iHO-1 and iHSP-70 were evaluated in cells from the blood of AD patients versus the control subjects. The present study demonstrated an elevated expression of both Th1 and Th2-associated cytokines in CD4+ T cells of AD patients, with a significant direct correlation between Th1 and Th2 cell populations, thus yielding insight into the immune features of the AD-associated systemic inflammatory profile.

CONCLUSION

Finally, the observed increased iHO-1 and iHSP-70 expressions likely represent adaptive physiologic countermeasures to AD-associated inflammatory tissue damage, suggesting that HSP inducers are promising candidates for the management of atopic disorders.

Advances in the modulation of ROS and transdermal administration for anti-psoriatic nanotherapies

Reactive oxygen species (ROS) at supraphysiological concentration have a determinate role in contributing to immuno-metabolic disorders in the epithelial immune microenvironment (EIME) of psoriatic lesions. With an exclusive focus on the gene-oxidative stress environment interaction in the EIME, a comprehensive strategy based on ROS-regulating nanomedicines is greatly anticipated to become the mainstay of anti-psoriasis treatment. This potential therapeutic modality could inhibit the acceleration of psoriasis via remodeling the redox equilibrium and reshaping the EIME. Herein, we present a marked overview of the current progress in the pathomechanisms of psoriasis, with particular concerns on the potential pathogenic role of ROS, which significantly dysregulates redox metabolism of keratinocytes (KCs) and skin-resident or -infiltrating cells. Meanwhile, the emergence of versatile nanomaterial-guided evolution for transdermal drug delivery has been attractive for the percutaneous administration of antipsoriatic therapies in recent years. We emphasize the underlying molecular mechanism of ROS-based nanoreactors for improved therapeutic outcomes against psoriasis and summarize up-to-date progress relating to the advantages and limitations of nanotherapeutic application for transdermal administration, as well as update an insight into potential future directions for nanotherapies in ROS-related skin diseases.

Heme Oxygenase 1 in Vertebrates: Friend and Foe

HO-1 is the inducible form of the enzyme heme-oxygenase. HO-1 catalyzes heme breakdown, reducing the levels of this important oxidant molecule and generating antioxidant, anti-inflammatory, and anti-apoptotic byproducts. Thus, HO-1 has been described as an important stress response mechanism during both physiologic and pathological processes. Interestingly, some findings are demonstrating that uncontrolled levels of HO-1 byproducts can be associated with cell death and tissue destruction as well. Furthermore, HO-1 can be located in the nucleus, influencing gene transcription, cellular proliferation, and DNA repair. Here, we will discuss several studies that approach HO-1 effects as a protective or detrimental mechanism in different pathological conditions. In this sense, as the major organs of vertebrates will deal specifically with distinct types of stresses, we discuss the HO-1 role in each of them, exposing the contradictions associated with HO-1 expression after different insults and circumstances.

Cell-penetrating heme oxygenase-1 in the therapy of atopic dermatitis in mice

Atopic dermatitis (AD), also referred to as atopic eczema, is a long-term inflammatory condition that is characterized by itchy, red, swollen and cracked skin. Accumulating evidence suggests that AD is caused by genetic factors, environmental exposure and immune system dysfunction; however, its underlying molecular mechanism remains unclear. Current treatment strategies aim to decrease the severity and frequency of flares. Heme oxygenase-1 (HO-1) is a nuclear factor erythroid 2-related factor 2 (Nrf2)-regulated gene that plays crucial roles against stress, inflammation and oxidation, and exerts cytoprotective effects. Previous studies have reported that treatment of AD induces high expression levels of HO-1 and Nrf2, indicating that HO-1 may play an important role in the treatment of AD. The present study constructed the recombinant protein, cell-penetrating peptide-HO-1 (CPP-HO-1), which was expressed in Escherichia coli and isolated with a 6xHis-tag using HiTrap His column (1 ml). AD was established using 4-dinitrochlorobenzene (DNCB) in mice. It was observed that the CPP-HO-1 fusion protein decreased the severity of AD, inhibited scratching in mice and decreased skin inflammation. Taken together, the results of the present study suggested that the CPP-HO-1 fusion protein may play a protective role against DNCB-induced AD in mice.

A population-based study on associations of stool microbiota with atopic diseases in school-age children

BACKGROUND

Infants with less diverse gut microbiota seem to have higher risks of atopic diseases in early life, but any associations at school age are unclear.

OBJECTIVES

This study sought to examine the associations of diversity, relative abundance, and functional pathways of stool microbiota with atopic diseases in school-age children.

METHODS

We performed a cross-sectional study within an existing population-based prospective cohort among 1440 children 10 years of age. On stool samples, 16S ribosomal RNA gene sequencing was performed, and taxonomic and functional tables were produced. Physician-diagnosed eczema, allergy, and asthma were measured by questionnaires, allergic sensitization by skin prick tests, and lung function by spirometry.

RESULTS

The α-diversity of stool microbiota was associated with a decreased risk of eczema (odds ratio [OR], 0.98; 95% CI, 0.97, 1.00), and β-diversity was associated with physician-diagnosed inhalant allergy (R² = 0.001; P = .047). Lachnospiraceae, Ruminococcaceae_UCG-005, and Christensenellaceae_R-7_group species were associated with decreased risks of eczema, inhalant allergic sensitization, and physician-diagnosed inhalant allergy (OR range, 0.88-0.94; 95% CI range, 0.79-0.96 to 0.88-0.98), while Agathobacter species were associated with an increased risk of physician-diagnosed inhalant allergy (OR, 1.23; 95% CI, 1.08-1.42). Functional pathways related to heme and terpenoid biosynthesis were associated with decreased risks of physician-diagnosed inhalant allergy and asthma (OR range, 0.89-0.86; 95% CI range, 0.80-0.99 to 0.73-1.02). No associations of stool microbiota with lung function were observed.

CONCLUSIONS

The diversity, relative abundance and functional pathways of stool microbiota were most consistently associated with physician-diagnosed inhalant allergy in school-age children and less consistently with other atopic diseases.

Chijabyukpi-Tang Inhibits Pro-Inflammatory Cytokines and Chemokines via the Nrf2/HO-1 Signaling Pathway in TNF-α/IFN-γ-Stimulated HaCaT Cells and Ameliorates 2,4-Dinitrochlorobenzene-Induced Atopic Dermatitis-Like Skin Lesions in Mice

Chijabyukpi-tang (CBT) is an oriental herbal formula consisting of three herbs (Gardeniae Fructus (Gardenia jasminoides J.Ellis.), Phellodendri Cortex (Phellodendron amurense Rupr.), Glycyrrhizae Radix (Glycyrrhiza uralensis Fisch. ex DC.) at the ratio of 2: 2: 1. CBT has traditionally been used to treat eczema with inflammation in Northeast Asia. The components of CBT have been shown to have anti-inflammatory and anti-oxidant properties, but the exact role and mechanism of CBT on atopic dermatitis (AD) remain unclear. In this study, we investigated the anti-inflammatory effect and mechanism of CBT in the HaCaT human keratinocyte cell line and investigated the anti-atopic effect in mice models of atopic dermatitis-like skin lesions. In the tumor necrosis factor alpha (TNF)-α/interferon (IFN)-γ-stimulated HaCaT cells, CBT inhibited the production of pro-inflammatory cytokines and chemokines and elevated the nuclear translocation of NF-E2 p45 related factors 2 (Nrf2) and subsequent production of heme oxygenase-1 (HO-1). CBT improved the symptoms of atopic dermatitis-like lesions in 2,4-dinitrochlorobenzene (DNCB)-treated mice by suppressing the levels of serum immunoglobulin E (IgE), and various pro-inflammatory cytokines and chemokines. The improvement effect of CBT on atopic dermatitis-like lesions can be predicted to be due to increased Nrf2 and HO-1 gene expression. These results suggest that CBT is an herbal medicine with the potential for use as a therapeutic agent for inflammatory skin diseases such as atopic dermatitis.

Caffeoyl-Pro-His amide relieve DNCB-Induced Atopic Dermatitis-Like phenotypes in BALB/c mice

The main factors involved in the pathogenesis of atopic dermatitis (AD) are skin barrier abnormality, allergy/immunology, and pruritus. Considering how oxidative stress influences these factors, antioxidant agents may be effective candidates in the treatment of AD. To evaluate the effect of Caffeoyl–Pro–His amide (CA-PH), an antioxidant agent, on 2,4-dinitrochlorobenzene (DNCB)-induced AD-like phenotypes in BALB/c mice. Topical sensitization and challenge by DNCB were performed on the dorsal skin of BALB/c mice to induce AD-like cutaneous lesions, phenotypes, and immunologic response. CA-PH was applied topically for 2 weeks to assess its effects on DNCB-induced AD-like phenotypes. As a result, CA-PH relieved DNCB-induced AD-like phenotypes quantified by dermatitis severity score, scratching duration, and trans-epidermal water loss. Histopathological analysis showed that CA-PH decreased epidermal thickening, the number of mast cells, and eosinophil infiltration in dermis. Immunohistochemical staining revealed that CA-PH recovered skin barrier-related proteins: filaggrin, involucrin, and loricrin. As for the immunologic aspects, CA-PH treatment lowered mRNA or protein levels of interleukin (IL)-4, IL-6, IL-17a, IL-1b, IL-31, and IL-33 levels and thymic stromal lymphopoietin (TSLP) levels in cutaneous tissue, reducing the DNCB-induced serum IgE level elevation. In conclusion, topical CA-PH may be a therapeutic option for the treatment of AD.

Heme Oxygenases: Cellular Multifunctional and Protective Molecules against UV-Induced Oxidative Stress

Ultraviolet (UV) irradiation can be considered as a double-edged sword: not only is it a crucial environmental factor that can cause skin-related disorders but it can also be used for phototherapy of skin diseases. Inducible heme oxygenase-1 (HO-1) in response to a variety of stimuli, including UV exposure, is vital to maintain cell homeostasis. Heme oxygenase-2 (HO-2), another member of the heme oxygenase family, is constitutively expressed. In this review, we discuss how heme oxygenase (HO), a vital rate-limiting enzyme, participates in heme catabolism and cytoprotection. Phylogenetic analysis showed that there may exist a functional differentiation between HO-1 and HO-2 during evolution. Furthermore, depending on functions in immunomodulation and antioxidation, HO-1 participates in disease progression, especially in pathogenesis of skin diseases, such as vitiligo and psoriasis. To further investigate the particular role of HO-1 in diseases, we summarized the profile of the HO enzyme system and its related signaling pathways, such as Nrf2 and endoplasmic reticulum crucial signaling, both known to regulate HO-1 expression. Furthermore, we report on a C-terminal truncation of HO-1, which is generally considered as a signal molecule. Also, a newly identified alternative splice isoform of HO-1 not only provides us a novel perspective on comprehensive HO-1 alternative splicing but also offers us a basis to clarify the relationship between HO-1 transcripts and oxidative diseases. To conclude, the HO system is not only involved in heme catabolism but also involved in biological processes related to the pathogenesis of certain diseases, even though the mechanism of disease progression still remains sketchy. Further understanding the role of the HO system and its relationship to UV is helpful for revealing the HO-related signaling networks and the pathogenesis of many diseases.

Soshiho-Tang, a Traditional Herbal Medicine, Alleviates Atopic Dermatitis Symptoms via Regulation of Inflammatory Mediators

Soshiho-tang (SST) is a well-known traditional herbal medicine used for the treatment of many diseases. The aims of this study are to investigate the effects of SST on atopic dermatitis (AD) symptoms and to examine its mechanism. Human keratinocyte (HaCaT) cells were stimulated with tumor necrosis factor alpha (TNF-α)/IFN-γ to induce AD-like keratinocyte environment. 2,4-Dinitrochlorobenzene (DNCB) was used to induce AD-like skin lesions in the dorsal skin of BALB/c mice. SST and dexamethasone were administered orally for 14 day. As a result, SST treatment increased the expression of heme oxygenase-1 (HO-1), an anti-oxidative factor, and the nuclear translocation of NF-E2 p45-related factor 2 (Nrf2). In addition, the treatment also decreased the expression level of inflammatory mediator nuclear factor-κB (NF-κB) and the adhesion molecule intercellular adhesion molecule-1 (ICAM-1). SST treatment (75 and 150 mg/kg) significantly relieved AD symptoms in DNCB-induced AD-like mice by restoring skin thickness, spleen weight, immunoglobulin E (IgE), interleukin 4 (IL-4), pro-inflammatory cytokine expression, and expression of several other mediators. We found that SST alleviates AD-like skin lesions and skin inflammation by modulating various atopic symptoms and inflammatory mediators. Therefore, SST can be used as an alternative drug for the treatment of AD.

Bilirubin oxidation derived from oxidative stress is associated with disease severity of atopic dermatitis in adults

BACKGROUND

Bilirubin is an essential antioxidant. Its oxidative metabolites, biopyrrins, are sensitive urinary markers of oxidative stress. Multiple studies suggest that oxidative stress affects the pathogenesis of skin diseases such as atopic dermatitis (AD).

AIM

To examine oxidative stress-induced bilirubin oxidation and its association with AD pathogenesis in adults.

METHODS

In total, 11 patients with AD and 7 healthy controls (HCs) were enrolled. Bilirubin oxidation profiles in the combined urine of the patients and that of the HCs were examined using high-performance liquid chromatography (HPLC) and fast atom bombardment mass spectrometry. The concentrations of urinary biopyrrins and serum biomarkers for AD disease severity, such as IgE and thymus and activation-regulated chemokine (TARC)/CCL17, were measured by ELISA to determine correlations between urinary biopyrrins and serum biomarkers. Local bilirubin oxidation in AD skin lesions was assessed by immunohistochemical analyses using two antibodies against bilirubin.

RESULTS

Levels of dipyrrole-monopyrrole-aldehyde, a novel urinary biopyrrin, were higher in patients with AD than in HCs, and increased with disease severity based on the SCORing Atopic Dermatitis (SCORAD) objective scoring system. Additionally, urinary biopyrrin levels correlated significantly with serum IgE and TARC/CCL17 levels. Furthermore, immunohistochemical analyses revealed that biopyrrins were strongly expressed in both infiltrating and resident cells in AD lesions. However, bilirubin was expressed at low levels in the lesions, suggesting that bilirubin oxidation is augmented in AD lesions.

CONCLUSIONS

Bilirubin oxidation derived from oxidative stress in the skin lesions can be associated with disease severity of AD.

2,3-Dimethoxy-2'-hydroxychalcone ameliorates TNF-α-induced ICAM-1 expression and subsequent monocyte adhesiveness via NF-kappaB inhibition and HO-1 induction in HaCaT cells

Up-regulation of adhesion molecules plays an important role in the infiltration of leukocytes into the skin during the development of various inflammatory skin diseases, such as atopic dermatitis. In this study, we investigated the modulatory effects of 2,3-dimethoxy-2′-hydroxychalcone (DMHC) on tumor necrosis factor (TNF)-α-induced intercellular adhesion molecule-1 (ICAM-1) expression and monocyte adhesiveness, as well as the molecular mechanisms underlying its action in the HaCaT human keratinocyte cell line. Pre-treating HaCaT cells with DMHC significantly suppressed TNF-α-induced ICAM-1 expression and subsequent monocyte adhesiveness. DMHC inhibited TNF-α-induced activation of NF-ᴋB. In addition, DMHC induced HO-1 expression as well as NRF2 activation. Furthermore, HO-1 knockdown using siRNA reversed the inhibitory effect of DMHC on TNF-α-induced ICAM-1 expression and adhesion of monocytes to keratinocytes. These results suggest that DMHC may inhibit TNF-α-induced ICAM-1 expression and adhesion of monocytes to keratinocytes by suppressing the signaling cascades leading to NF-ᴋB activation and inducing HO-1 expression in keratinocytes. [BMB Reports 2016; 49(1): 57-62]

Fraxetin Induces Heme Oxygenase-1 Expression by Activation of Akt/Nrf2 or AMP-activated Protein Kinase α/Nrf2 Pathway in HaCaT Cells

Background

Fraxetin (7,8-dihydroxy-6-methoxy coumarin), a coumarin derivative, has been reported to possess antioxidative, anti-inflammatory and neuroprotective effects. A number of recent observations suggest that the induction of heme oxygenase-1 (HO-1) inhibits inflammation and tumorigenesis. In the present study, we determined the effect of fraxetin on HO-1 expression in HaCaT human keratinocytes and investigated its underlying molecular mechanisms.

Methods

Reverse transcriptase-PCR and Western blot analysis were performed to detect HO-1 mRNA and protein expression, respectively. Cell viability was measured by the MTS test. The induction of intracellular reactive oxygen species (ROS) by fraxetin was evaluated by 2′,7′-dichlorofluorescin diacetate staining.

Results

Fraxetin upregulated mRNA and protein expression of HO-1. Incubation with fraxetin induced the localization of nuclear factor-erythroid-2-related factor-2 (Nrf2) in the nucleus and increased the antioxidant response element-reporter gene activity. Fraxetin also induced the phosphorylation of Akt and AMP-activated protein kinase (AMPK)α and diminished the expression of phosphatase and tensin homolog, a negative regulator of Akt. Pharmacological inhibition of Akt and AMPKα abrogated fraxetin-induced expression of HO-1 and nuclear localization of Nrf2. Furthermore, fraxetin generated ROS in a concentration-dependent manner.

Conclusions

Fraxetin induces HO-1 expression through activation of Akt/Nrf2 or AMPKα/Nrf2 pathway in HaCaT cells.

Oxidative Stress in Atopic Dermatitis

Atopic dermatitis (AD) is a chronic pruritic skin disorder affecting many people especially young children. It is a disease caused by the combination of genetic predisposition, immune dysregulation, and skin barrier defect. In recent years, emerging evidence suggests oxidative stress may play an important role in many skin diseases and skin aging, possibly including AD. In this review, we give an update on scientific progress linking oxidative stress to AD and discuss future treatment strategies for better disease control and improved quality of life for AD patients.

Curcumin ameliorates TNF-α-induced ICAM-1 expression and subsequent THP-1 adhesiveness via the induction of heme oxygenase-1 in the HaCaT cells

Adhesion molecules such as ICAM-1 are important in the infiltration of leukocytes into the site of inflammation. In this study, we investigated the inhibitory effects of curcumin on ICAM-1 expression and monocyte adhesiveness as well as its underlying action mechanism in the TNF-α-stimulated keratinocytes. Curcumin induced expression of heme oxygenase-1 (HO-1) in the human keratinocyte cell line HaCaT. In addition, curcumin induced Nrf2 activation in dose- and time-dependent manners in the HaCaT cells. Curcumin suppressed TNF-α- induced ICAM-1 expression and subsequent monocyte adhesion, which were reversed by the addition of tin protoporphyrin IX (SnPP), a specific inhibitor of HO-1, or HO-1 knockdown using siRNA. Furthermore, Nrf2 knockdown using siRNA reversed the inhibitory effect of curcumin on the TNF-α-induced ICAM-1 expression and adhesion of monocytes to keratinocytes. These results suggest that curcumin may exert its anti-inflammatory activity by suppressing the TNF-α-induced ICAM-1 expression and subsequent monocyte adhesion via expression of HO-1 in the keratinocytes. [BMB Reports 2013;46(8): 410-415]

Serum heme oxygenase-1 as a marker of lung function decline in patients with chronic silicosis

OBJECTIVE

To identify predictive factors of excess decline in forced expiratory volume in one second (FEV1) in patients with chronic silicosis.

METHODS

Forty-six male patients enrolled in 2004 were screened and received pulmonary function tests.

RESULTS

Among the 33 included patients, 12 were categorized as rapid decliners (reduction in FEV1 > 60 mL/yr). The mean level of serum heme oxygenase-1 (HO-1), a marker of oxidative stress, was significantly lower in rapid decliners than in normal decliners (P = 0.002). Logistic regression analysis revealed that serum HO-1 was a factor affecting clinically important decline in FEV1 (odds ratio = 0.52; 95% confidence interval, 0.31 to 0.88) independent of the effects of age, height, weight, smoking, exposure status, and C-reactive protein.

CONCLUSIONS

Serum HO-1 may be a predictor of lung function decline in silicosis patients.

Manganese superoxide dismutase depletion in murine hematopoietic stem cells perturbs iron homeostasis, globin switching, and epigenetic control in erythrocyte precursor cells

Heme synthesis partially occurs in the mitochondrial matrix; thus there is a high probability that enzymes and intermediates important in the production of heme will be exposed to metabolic by-products including reactive oxygen species. In addition, the need for ferrous iron for heme production, Fe/S coordination, and other processes occurring in the mitochondrial matrix suggests that aberrant fluxes of reactive oxygen species in this compartment might perturb normal iron homeostasis. Manganese superoxide dismutase (Sod2) is an antioxidant enzyme that governs steady-state levels of the superoxide in the mitochondrial matrix. Using hematopoietic stem cell-specific conditional Sod2 knockout mice we observed increased superoxide concentrations in red cell progeny, which caused significant pathologies including impaired erythrocytes and decreased ferrochelatase activity. Animals lacking Sod2 expression in erythroid precursors also displayed extramedullary hematopoiesis and systemic iron redistribution. Additionally, the increase in superoxide flux in erythroid precursors caused abnormal gene regulation of hematopoietic transcription factors, globins, and iron-response genes. Moreover, the erythroid precursors also displayed evidence of global changes in histone posttranslational modifications, a likely cause of at least some of the aberrant gene expression noted. From a therapeutic translational perspective, mitochondrially targeted superoxide-scavenging antioxidants partially rescued the observed phenotype. Taken together, our findings illuminate the superoxide sensitivity of normal iron homeostasis in erythrocyte precursors and suggest a probable link between mitochondrial redox metabolism and epigenetic control of nuclear gene regulation during mammalian erythropoiesis.

The protective effects of oxyresveratrol imine derivative against hydrogen peroxide-induced cell death in PC12 cells

Oxyresveratrol (2',3,4',5-tetrahydroxystilbene) is a naturally occurring ingredient found in mulberries that shows potential as an antioxidant, anti-inflammatory, and neuroprotective agent. This study was performed to identify materials similar to oxyresveratrol that may have more effective antioxidant properties. We synthesized a stilbene analog referred to as Compound 1 (2',3,4',5-tetramethoxystilbene); a benzamide analog referred to as Compound 2 ((2,4-dimethoxyphenyl)-3,5-dimethoxybenzamide); and three imine analogs referred to as Compound 3 (3,5-dimethoxybenzylidene)-(2,4-dimethoxyphenylamine), Compound 4 ((4-methoxybenzylidene)-(3-methoxyphenyl)amine), and Compound 5 ((4-methoxybenzylidene)phenylamine). The cytoprotective effects of these compounds were subsequently evaluated using hydrogen peroxide-treated PC12 cells. The cytoprotective effects of the imine analogs were greater than the effects of oxyresveratrol and the other analogs at concentrations of 200 μM. The Compound 3, which is the most effective imine analog of oxyresveratrol, exhibited these cytoprotective effects against hydrogen peroxide-induced oxidative stress through the regulation of heme oxygenase-1 (HO-1) expression and the translocation of nuclear factor E2-related factor 2 (Nrf2). Our results suggest that imine analogs of oxyresveratrol may be useful agents in reducing neuronal oxidative damage.

Carbon monoxide-treated dendritic cells decrease β1-integrin induction on CD8⁺ T cells and protect from type 1 diabetes

Carbon monoxide (CO) treatment improves pathogenic outcome of autoimmune diseases by promoting tolerance. However, the mechanism behind this protective tolerance is not yet defined. Here, we show in a transgenic mouse model for autoimmune diabetes that ex vivo gaseous CO (gCO)-treated DCs loaded with pancreatic β-cell peptides protect mice from disease. This protection is peptide-restricted, independent of IL-10 secretion by DCs and of CD4(+) T cells. Although no differences were observed in autoreactive CD8(+) T-cell function from gCO-treated versus untreated DC-immunized groups, gCO-treated DCs strongly inhibited accumulation of autoreactive CD8(+) T cells in the pancreas. Interestingly, induction of β1-integrin was curtailed when CD8(+) T cells were primed with gCO-treated DCs, and the capacity of these CD8(+) T cells to lyse isolated islet was dramatically impaired. Thus, immunotherapy using CO-treated DCs appears to be an original strategy to control autoimmune disease.

Microsatellite polymorphism in the heme oxygenase-1 gene promoter and the risk of psoriasis in Taiwanese

Psoriasis is a chronic disease characterized by inflammation of the skin. The expression of heme oxygenase-1 (HO-1), the rate-limiting enzyme involved in heme degradation, correlates well with the severity of psoriasis, and is a heritable trait. This study aimed to assess the role of (GT)(n) dinucleotide repeat polymorphisms in the promoter region of the HO-1 gene in Chinese-Taiwanese patients with psoriasis. In total, 288 patients with psoriasis and 542 control subjects were analyzed for the presence of the HO-1 microsatellite polymorphism by using polymerase chain reaction. The alleles were classified as the S and L alleles according to the number of (GT)(n) repeats, with the alleles with ≤26 repeats designated as S and alleles with ≥27 repeats designated as L alleles. The subjects were then classified as having S/S, S/L, or L/L genotypes according to each of their HO-1 alleles. No significant difference was observed in either the genotype or allele distribution between the patients and healthy controls. However, the average number of repeats of both alleles in psoriasis patients with late disease onset was lower than that of psoriasis patients with early disease onset (26.7 ± 3.2 vs. 27.5 ± 3.4; P = 0.043, adjusted for age and sex), but the difference was not significant after additional adjustment for body mass index, smoking, diabetes, and hypertension (P = 0.189). Our results suggest that the HO-1 microsatellite polymorphism may not contribute to the genetic background of psoriasis in Chinese-Taiwanese patients.

Bach1 regulates osteoclastogenesis in a mouse model via both heme oxygenase 1-dependent and heme oxygenase 1-independent pathways

OBJECTIVE

Reducing inflammation and osteoclastogenesis by heme oxygenase 1 (HO-1) induction could be beneficial in the treatment of rheumatoid arthritis (RA). However, the function of HO-1 in bone metabolism remains unclear. This study was undertaken to clarify the effects of HO-1 and its repressor Bach1 in osteoclastogenesis.

METHODS

In vitro osteoclastogenesis was compared in Bach1-deficient and wild-type mice. Osteoclasts (OCs) were generated from bone marrow-derived macrophages by stimulation with macrophage colony-stimulating factor and RANKL. Osteoclastogenesis was assessed by tartrate-resistant acid phosphatase staining and expression of OC-related genes. Intracellular signal pathways in OC precursors were also assessed. HO-1 short hairpin RNA (shRNA) was transduced into Bach1(-/-) mouse bone marrow-derived macrophages to examine the role of HO-1 in osteoclastogenesis. In vivo inflammatory bone loss was evaluated by local injection of tumor necrosis factor α (TNFα) into calvaria.

RESULTS

Transcription of HO-1 was down-regulated by stimulation with RANKL in the early stage of OC differentiation. Bach1(-/-) mouse bone marrow-derived macrophages were partially resistant to the RANKL-dependent HO-1 reduction and showed impaired osteoclastogenesis, which was associated with reduced expression of RANK and components of the downstream TNF receptor-associated factor 6/c-Fos/NF-ATc1 pathway as well as reduced expression of Blimp1. Treatment with HO-1 shRNA increased the number of OCs and expression of OC-related genes except for the Blimp1 gene during in vitro osteoclastogenesis from Bach1(-/-) mouse bone marrow-derived macrophages. TNFα-induced bone destruction was reduced in Bach1(-/-) mice in vivo.

CONCLUSION

The present findings demonstrate that Bach1 regulates osteoclastogenesis under inflammatory conditions, via both HO-1-dependent and HO-1-independent mechanisms. Bach1 may be worthy of consideration as a target for treatment of inflammatory bone loss in diseases including RA.

Bryonolic acid transcriptional control of anti-inflammatory and antioxidant genes in macrophages in vitro and in vivo

Bryonolic acid (BA) (1) is a naturally occurring triterpenoid with pleiotropic properties. This study characterizes the mechanisms mediating the anti-inflammatory and antioxidant activities of BA and validates the utility of BA as a tool to explore the relationships between triterpenoid structure and activity. BA reduces the inflammatory mediator NO by suppressing the expression of the inflammatory enzyme inducible nitric oxide synthase (iNOS) in LPS-activated RAW 264.7 macrophage cells. In addition, BA robustly induces the antioxidant protein heme oxygenase-1 (HO-1) in vitro and in vivo in an Nrf2-dependent manner. Further analyses of Nrf2 target genes reveal selectivity for the timing and level of gene induction by BA in treated macrophages with distinct patterns for Nrf2-regulated antioxidant genes. Additionally, the distinct expression profile of BA on Nrf2 target genes relative to oleanolic acid suggests the importance of the triterpenoid scaffold in dictating the pleiotropic effects exerted by these molecules.

Celastrol induces expression of heme oxygenase-1 through ROS/Nrf2/ARE signaling in the HaCaT cells

We previously demonstrated that celastrol, a quinone methide triterpenoid derived from the medicinal plant Tripterygium wilfordii, exerts its anti-inflammatory activity through up-regulation of heme oxygenase-1 (HO-1) expression in the keratinocytes. In this study, we examined the signaling pathways that lead to the up-regulation of HO-1 expression by celastrol. In HaCaT cells, celastrol-induced HO-1 expression was dependent on ROS generation. ERK and p38 MAPK were major MAPK pathways responsible for celastrol-induced HO-1 expression. Celastrol induced Nrf2 activation. Nrf2 knockdown using small interfering RNA (siRNA) inhibited celastrol-induced HO-1 expression. Treatment with celastrol resulted in a marked increase in antioxidant response element (ARE)-driven transcriptional activity, which was dependent on ROS generation and activation of ERK and p38 MAPK. Furthermore, Nrf2 siRNA significantly reversed the inhibitory effect of celastrol on IFN-γ-induced expression of ICAM-1 in the keratinocytes. Taken together, our results indicate that celastrol can activate the ROS-ERK/p38-Nrf2-ARE signaling cascades leading to the up-regulation of HO-1 which is partly responsible for its anti-inflammatory activity in the keratinocytes.

Heme oxygenase-1 expression protects melanocytes from stress-induced cell death: implications for vitiligo

To study protection of melanocytes from stress-induced cell death by heme oxygenases during depigmentation and repigmentation in vitiligo, expression of isoforms 1 and 2 was studied in cultured control and patient melanocytes and normal skin explants exposed to UV or bleaching agent 4-TBP. Similarly, expression of heme oxygenases was followed in skin from vitiligo patients before and after PUVA treatment. Single and double immunostainings were used in combination with light and confocal microscopic analysis and Western blotting. Melanocyte expression of heme oxygenase 1 is upregulated, whereas heme oxygenase 2 is reduced in response to UV and 4-TBP. Upregulation of inducible heme oxygenase 1 was also observed in UV-treated explant cultures, in skin of successfully PUVA-treated patients and in melanocytes cultured from vitiligo non-lesional skin. Heme oxygenase encoding genes were subsequently cloned to study consequences of either gene product on cell viability, demonstrating that HO-1 but not HO-2 overexpression offers protection from stress-induced cell death in MTT assays. HO-1 expression by melanocytes may contribute to beneficial effects of UV treatment for vitiligo patients.

Interleukin-18 is elevated in the horny layer in patients with atopic dermatitis and is associated with Staphylococcus aureus colonization

BACKGROUND

An increase in interleukin (IL)-18 production from epidermal cells has been reported in an atopic dermatitis (AD) mouse model, and subsequent topical application of Staphylococcus aureus results in severe dermatitis.

OBJECTIVES

To reveal the relationship between S. aureus colonization of skin lesions and keratinocyte IL-18 production, particularly in AD with relatively low serum IgE levels. We also aimed to establish a simple and noninvasive method of assaying IL-18 produced by epidermal keratinocytes to evaluate local skin inflammation and therapeutic effects in patients with AD.

METHODS

IL-18 in the horny layer of the skin was collected via a tape-stripping method and measured in 95 patients with AD and 40 healthy controls by enzyme-linked immunosorbent assay (ELISA). Clinical severity, blood data and S. aureus skin colonization were evaluated before and after treatment.

RESULTS

IL-18 levels in the horny layer were significantly higher in the skin lesions of patients with AD than in healthy controls and correlated with SCORAD, levels of serum IL-18, IgE, lactate dehydrogenase, thymus and activation-regulated chemokine, blood eosinophils and transepidermal water loss. In the AD group with serum IgE < 1500 IU mL(-1) , significantly higher IL-18 levels were observed in the horny layer of patients colonized with S. aureus compared with those who were not.

CONCLUSIONS

Epidermal IL-18 production was associated with the severity of AD. Staphylococcus aureus colonization seems to contribute to this IL-18 production, especially in the AD group with relatively low IgE production. Tape stripping provides an easy and noninvasive method to assess epidermal IL-18 production by ELISA.

(2S)-2′-methoxykurarinone from Sophora flavescens suppresses cutaneous T cell-attracting chemokine/CCL27 expression induced by interleukin-ß/tumor necrosis factor-α via heme oxygenase-1 in human keratinocytes

One of the CC chemokines, cutaneous T cell-attracting chemokine (CTACK/CCL27), is a skin-specific CC chemokine that is produced constitutively by keratinocytes and is highly up-regulated in inflammatory skin conditions such as atopic dermatitis and contact dermatitis. (2S)-2′-Methoxykurarinone (MOK) from Sophora flavescens has been demonstrated to have antioxidant effects. Heme oxygenase (HO)-1 has recently emerged as an important cytoprotective enzyme against oxidative stress and inflammatory responses in many cell types. This study aimed to define whether and how MOK regulates skin specific CTACK/CCL27 chemokine production in human HaCaT keratinocytes. The level of CTACK/CCL27 and HO-1 expression was measured by reverse transcription-polymerase chain reaction, and signaling was evaluated by western blot analysis. CTACK/CCL27 production was determined by enzyme-linked immunosorbent assay. Pretreatment with MOK suppressed tumor necrosis factor-α (TNF-α)- and interleukin (IL)-1ß-induced CTACK/CCL27 production in human HaCaT keratinocytes. MOK inhibited TNF-α- and IL-1ß-induced nuclear factor κB (NF-κB) activation. Interestingly, pretreatment with MOK significantly suppressed TNF-α- and IL-1ß-induced CTACK/CCL27 production through the induction of HO-1. This suppression was completely abolished by HO-1 small interfering RNA. Furthermore, carbon monoxide, but not other end products of HO-1 activity, also suppressed TNF-α- and IL-1ß-induced CTACK/CCL27 production. These results demonstrate that MOK attenuates TNF-α- and IL-1ß-induced production of CTACK/CCL27 in human HaCaT keratinocytes by inhibiting NF-κB activation and induction of HO-1.

Immunoregulatory properties of heme oxygenase-1

Heme oxygenase-1 (HO-1) is one of the three isoforms of the heme oxygenase enzyme that catabolyzes the degradation of heme into biliverdin with the production of free iron and CO. HO-1 is induced by its substrate and by other stimuli, including agents involved in oxidative stress and proinflammatory cytokines as well as several anti-inflammatory stimuli. A growing body of evidence points toward the capacity of this molecule to inhibit immune reactions and the pivotal role of HO-1 in inflammatory diseases. We will first review the physiological role of HO-1 as determined by the analysis of HO-1-deficient individuals. This will be followed by an examination of the effect of HO-1 within immunopathological contexts such as immune disorders (autoimmunity and allergy) or infections. A section will be devoted to the use of an HO-1 inducer as an immunosuppressive molecule in transplantation. Finally, we will review the molecular basis of HO-1 actions on different immune cells.

Sulforaphane suppresses TARC/CCL17 and MDC/CCL22 expression through heme oxygenase-1 and NF-κB in human keratinocytes

Sulforaphane (4-methylsulfinylbutyl isothiocyanate, SFN) from broccoli has been used a chemopreventive photochemical as detoxification of xenobiotics and anti-inflammatory, however, there is no studies for Th2 chemokine expression through heme oxygenase-1 and NF-κB in keratinocytes. Atopic dermatitis is a chronically relapsing pruritic inflammatory skin disease. SFN is demonstrated to have anti-inflammatory and anti-oxidant effects. This study aimed to define whether and how SFN regulates Th2-related chemokine production in human HaCaT keratinocytes. The level of chemokine expression was measured by reverse transcription polymerase chain reaction (RT-PCR) and signaling study was performed by Western blot analysis. Chemokine production was determined by enzyme-linked immunosorbent assay. Pretreatment with SFN suppressed interferon-γ (IFN-γ) and tumor necrosis factor (TNF)-α- induced thymus- and activation-regulated chemokine (TARC/CCL17) and macrophage-derived chemokine (MDC/CCL22) production in HaCaT keratinocytes. SFN inhibited IFN-γ and TNF-α-induced NF-κB activation as well as STAT1 activation. Interestingly, pretreatment with SFN result in significantly suppressed IFN-γ and TNF-α-induced TARC/CCL17 and MDC/CCL22 production through the induction of HO-1. This suppression was completely abolished by HO-1 siRNA. Furthermore, Carbon monoxide, but not other end products of HO-1 activity, also suppressed IFN-γ and TNF-α-induced TARC/CCL17 and MDC/CCL22 production. These results demonstrate that SFN has an inhibitory role in IFN-γ and TNF-α-induced production of TARC/CCL17 and MDC/CCL22 in human HaCaT cells by inhibition of NF-κB activation and induction of HO-1.

Plasma heme oxygenase-1 concentration is elevated in individuals with type 2 diabetes mellitus

Background

Circulating concentrations of heme oxygenase-1 (HO-1) have been recently reported to be elevated in several chronic disorders. However, no study has ever examined the association between circulating HO-1 concentrations and type 2 diabetes mellitus (T2DM).

Methods and Findings

581 cases with newly-diagnosed T2DM (New-T2DM) and 611 comparison controls were recruited in this two-phase case-control study, comprising 420 cases and 429 controls collected in the first phase study and 161 cases and 182 controls in the second phase replication study. Analyses, using both separated data and combined data from the two-phase studies, show that plasma HO-1 concentrations were significantly increased in New-T2DM cases compared to controls (P<0.001). Plasma HO-1 concentrations were significantly correlated with plasma glucose concentrations, HOMA-beta and HOMA-IR (P<0.001). After adjustment for age, sex, BMI and family history of diabetes, the ORs for New-T2DM in the highest quartile of plasma HO-1 concentrations, compared with the lowest, was 8.23 (95% CI 5.55–12.21; P for trend <0.001). The trend remained significant after additional adjustment for fasting plasma glucose/insulin, HOMA-beta/HOMA-IR, TC/TG, smoking, drinking and history of hypertension, and even in further stratification analysis by age, sex, BMI, smoking, drinking and history of hypertension.

Conclusions

Elevated plasma HO-1 concentrations are associated with higher ORs for New-T2DM, which add more knowledge regarding the important role of oxidative stress in T2DM. More consequent studies were warranted to confirm the clinical utility of plasma HO-1, especially in diagnosis and prognosis of T2DM and its complications.

Pro-healing potential of hemin: an inducer of heme oxygenase-1

Hemin induces heme oxygenase (HO), an enzyme which degrades heme in a rate-limiting manner and has an important role in cellular protection against oxidative stress and apoptosis. This HO inducer may be of potential therapeutic value in wound healing and inflammation. To identify the beneficial activity of HO vis a vis wound healing, hemin was used as inducer of HO in rats using a full-thickness cutaneous wound model. Hemin treatment increased cellular proliferation and collagen synthesis as evidenced by increase in wound contraction and hydroxyproline and glucosamine contents. mRNA expression of cytokines endorsed fast healing as was indicated by inhibition of pro-inflammatory cytokines such as ICAM-1 and TNF-alpha and up-regulation of anti-inflammatory cytokine IL-10.

Expression of heme oxygenase-1 in human leukemic cells and its regulation by transcriptional repressor Bach1

Heme oxygenase (HO)-1 has anti-oxidative, anti-inflammatory, and anti-apoptotic activities. However, little is known about the regulation of HO-1 in human primary acute myeloid leukemia (AML) cells. Here we investigated the expression of HO-1 in primary and established AML cells as well as other types of leukemic cells and normal monocytes, and its regulatory mechanism by the transcriptional repressor, BTB and CNC homology 1 (Bach1), and the activator, nuclear factor erythroid-derived 2 related factor 2 (Nrf2). Leukemic cell lines such as U937 expressed little HO-1, whereas most freshly isolated AML cells and monocytes expressed substantial amounts of HO-1, along with Bach1 and Nrf2. When U937 cells were treated with phorbol myristate acetate (PHA) or gamma-interferon, they significantly expressed both HO-1 and Bach1, like primary AML cells. Treatment with lipopolysaccharide (LPS) enhanced HO-1 expression in U937 cells but suppressed it in primary monocytes and PMA-treated U937 cells. In HO-1-expressing cells, Bach1 was localized in the cytoplasm, but Nrf2 was localized in the nuclei. Chromatin immunoprecipitation assay of these cells revealed the preferential binding of Nrf2 over Bach1 to Maf-recognition elements, the enhancer regions of the HO-1 gene. The downregulation of the HO-1 gene with siRNA increased a cytotoxic effect of an anticancer drug on primary AML cells, whereas the downregulation of Bach1 increased HO-1 expression, leading to enhanced survival. These and other results show that Bach1 plays a critical role in regulating HO-1 gene expression in AML cells and its expression suppresses their survival by downregulating HO-1 expression. Thus, functional upregulation of Bach1 is a potential strategy for antileukemic therapy.

A Role of Staphyococcus aureus, Interleukin-18, Nerve Growth Factor and Semaphorin 3A, an Axon Guidance Molecule, in Pathogenesis and Treatment of Atopic Dermatitis

Staphylococcus aureus (SA) is usually present not only in the skin lesions of atopic dermatitis (AD) but also in the atopic dry skin. SA discharges various toxins and enzymes that injure the skin, results in activation of epidermal keratinocytes, which produce and release IL-18. IL-18 that induces the super Th1 cells secreting IFN-γ and IL-13 is supposed to be involved in development of AD and its pathogenesis. Indeed, the number of SA colonies on the skin surface and the serum IL-18 levels in patients with AD significantly correlated with the skin scores of AD lesions. Also, there is strong positive correlation between the skin scores and serum IL-18 levels in DS-Nh mice (P<0.0001, r=0.64), which develop considerable AD-like legions when they are housed under conventional conditions, but develop skin legions with less severity and less frequency under specific pathogens free (SPF) conditions. Therefore, they are well-known as model mice of AD, in which SA is presumed to be critical factor for the development of AD lesions. Also, theses DS-Nh mice pretreated with Cy developed more remarkable AD-like lesions in comparison with non-treated ones. The levels of INF-r and IL-13 in the supernatants of the lymph node cell cultures stimulated with staphylococcal enterotoxin B (SEB) or ConA were increased in the Cy-treated mice, although the serum levels of total IgE were not. In this experiment, we revealed that Cy-treated mice, to which CD25 +CD4 + reguratory T cells taken from non-treated ones had been transferred, developed the AD-like legions with less severity and less number of SA colonies on the skin surface. Therefore, it is presumed that CD25 +CD4 + reguratory T cells might be involved in the suppression of super Th1 cells which are induced by IL-18 and are involved in the development of AD-like lesions rather than IgE production. The efficient induction of CD25 +CD4 + reguratory T cells is expected for the new type of treatment of AD. We also found that farnesol (F) and xylitol (X) synergistically inhibited biofilm formation by SA, and indeed the ratio of SA in total bacteria at sites to which the FX cream containing F and X had been applied was significantly decreased 1 week later, accompanied with improvement of AD, when compared with that before application and at placebo sites. Therefore, the FX cream is a useful skin-care agent for atopic dry skin colonized by SA. The nerve growth factor (NGF) in the horny layer (the horn NGF) of skin lesions on the cubital fossa was collected by tape stripping and measured using ELISA in AD patients before and after 2 and 4 weeks treatments. Simultaneously, the itch and eruptions on the whole body and on the lesions, in which the horn NGF was measured, were recorded, and also the peripheral blood eosinophil count, serum LDH level and serum total IgE level were examined. The level of NGF was significantly higher in AD patients than in healthy controls, correlated with the severity of itch, erythema, scale/xerosis, the eosinophil count and LDH level, and also significantly decreased after treatments with olopatadine and/or steroid ointment for 2 and 4 weeks. Therefore, the measurement of the NGF by this harmless method seems to be useful to assess the severity of AD and the therapeutic effects on AD. In AD patients, C-fiber in the epidermis increase and sprout, inducing hypersensitivity, which is considered to aggravate the disease. Semaphorin 3A (Sema3A), an axon guidance molecule, is a potent inhibitor of neurite outgrowth of sensory neurons. We administered recombinant Sema3A intracutaneously into the skin lesions of NC/Nga mice, an animal model of AD, and investigated the effect of Sema3A on the skin lesions and their itch. Sema3A dose-dependently improved skin lesions and attenuated the scratching behavior in NC/Nga mice. Histological examinations revealed a decrease in the epidermal thickness, the density of invasive nerve fibers in the epidermis, inflammatory infiltrate including mast cells and CD4 +T cells, and the production of IL-4 in the Sema3A-treated lesions. Because the interruption of the itch-scratch cycle likely contributes to the improvement of the AD-like lesions, Sema3A is expected to become a promising treatment of patients with refractory AD.

Serum HO-1 is useful to make differential diagnosis of secondary hemophagocytic syndrome from other similar hematological conditions

Heme oxygenase (HO)-1, a heme-degrading enzyme inducible by various stimuli, plays a key role in the regulation of inflammatory response in monocytes/macrophages. The serum HO-1 level is remarkably increased in patients with secondary hemophagocytic syndrome (HPS) or adult-onset Still's disease. We measured serum HO-1 levels in patients with a variety of hematological diseases, including secondary HPS, by means of ELISA. Serum HO-1 levels were significantly higher in 22 patients with HPS (134.7 +/- 116.2 ng/mL, P < 0.0001) at diagnosis than in 80 patients with other hematological diseases. The most effective cutoff point between HPS and other conditions was 14.5 ng/mL, with 100.0% sensitivity and 96.3% specificity. In HPS patients, the serum HO-1 levels showed the highest correlation with serum ferritin (r = 0.682, P = 0.0005), which reflects the disease activity of HPS. Moreover, both HO-1 and ferritin levels were reduced in parallel after successful treatment in patients with HPS, irrespective of underlying diseases. However, HO-1 levels were not elevated in patients with other causes of hyperferritinemia. These data demonstrate that serum HO-1 can distinguish secondary HPS from other hematological diseases, including those associated with hyperferritinemia.

Advances in allergic skin disease, anaphylaxis, and hypersensitivity reactions to foods, drugs, and insects in 2008

This review highlights some of the research advances in anaphylaxis, and hypersensitivity reactions to foods, drugs, and insects and in allergic skin disease that were reported in the Journal in 2008. Key epidemiologic observations include a rise in anaphylaxis in a population-based study and lower rates of peanut allergy in Israel, where infants consume peanut early compared with the United Kingdom, where dietary introduction is generally delayed. Advances in food allergy diagnosis include IgE epitope mapping that discloses the likelihood and severity of allergy; studies correlating likelihood of clinical reactivity on the basis of food-specific IgE to sesame, peanut, milk, and tree nuts; and an observation that a low baseline angiotensin-converting enzyme level may be associated with having pharyngeal edema during a reaction. Molecular, immunologic, and genetic studies are discerning pathways that are key in development of food allergy, identifying new modalities to interrupt mast cell degranulation, and elucidating risks associated with penicillin allergy. Regarding treatment, clinical studies show a majority of children with milk and egg allergy tolerate these proteins in modest amounts when they are extensively heated in baked goods, and studies show promise for oral immunotherapy to treat milk allergy and sublingual immunotherapy for honey bee venom hypersensitivity. The importance of skin barrier dysfunction has continued to be highlighted in the pathophysiology of atopic dermatitis (AD). Research has also continued to identify immunologic defects that contribute to the propensity of patients with AD to develop viral and bacterial infection. New therapeutic approaches to AD, urticaria, and angioedema have been reported including use of probiotics, biologics, vitamin D, and skin barrier creams.

Heme oxygenase-1: its therapeutic roles in inflammatory diseases

Heme oxygenase (HO)-1 is an inducible enzyme that catalyzes the first and rate-limiting step in the oxidative degradation of free heme into ferrous iron, carbon monoxide (CO), and biliverdin (BV), the latter being subsequently converted into bilirubin (BR). HO-1, once expressed during inflammation, forms high concentrations of its enzymatic by-products that can influence various biological events, and this expression is proven to be associated with the resolution of inflammation. The degradation of heme by HO-1 itself, the signaling actions of CO, the antioxidant properties of BV/BR, and the sequestration of ferrous iron by ferritin all concertedly contribute to the anti-inflammatory effects of HO-1. This review focuses on the anti-inflammatory mechanisms of HO-1 actions and its roles in inflammatory diseases.