Atopic dermatitis-like skin lesions are suppressed in fat-1 transgenic mice through the inhibition of inflammasomes

Hydrogel-Based Treatment of House Dust Mite-Induced Atopic Dermatitis through Triple Cleaning of Mites, Bacteria, and ROS-Related Inflammation

Atopic dermatitis (AD) is a chronic and recurrent inflammatory disease caused by abnormalities in skin immunoregulation. House dust mite can directly damage the skin barrier and thus sensitize the skin, which is one of the main allergens inducing AD in humans and widely exists in daily life. Meanwhile, the accompanying bacterial infections and exposure to additional allergens exacerbate the condition by generating excessive reactive oxygen species (ROS). Herein, we have developed the CPDP hydrogel with injectable and self-healing ability to combat pathogenic microorganisms and inflammatory environments for AD therapy. In vitro experiments have affirmed the efficacy of the CPDP hydrogel in combating mites, killing bacteria, and scavenging ROS. In a mouse model closely mimicking HDM-induced AD, the CPDP hydrogel has shown superior therapeutic effects, including reducing epidermal thickness and mast cell count, increasing collagen deposition, as well as down-regulating pro-inflammatory factors.

Effect of Chloroquine on Type 2 Inflammatory Response in MC903-Induced Atopic Dermatitis Mice

Introduction

Atopic dermatitis (AD) is a chronic, non-infectious inflammatory dermatosis. Chloroquine (CQ) has long been proven to possess anti-inflammatory properties.

Objective

This paper aims to investigate the impact of CQ on type 2 inflammatory response in MC903-induced AD mice.

Methods

An AD mouse model was established via MC903 induction. After CQ treatment, AD mice were intraperitoneally injected with polyinosinic: polycyclic acid [poly (I:C)] or Nigericin. Dermatitis severity was scored, and the thickness of the left ear was measured. The pathological changes in mouse skin tissues were observed by H&E staining. The number of mast cells was counted via TB staining. The content of peripheral blood T-helper 2 (Th2) cells and levels of immunoglobulin E (IgE), thymic stromal-derived lymphopoietin (TSLP), interleukin (IL)-4, IL-13, interferon (IFN)-γ, IL-1β, and IL-18 were assessed by flow cytometry and ELISA. The levels of toll-like receptor 3 (TLR3), NLRP3, ASC, and cleaved caspase-1 proteins in skin tissues were determined by Western blot.

Results

CQ treatment abated dermatitis severity and left ear thickness in AD mice, alleviated skin damage, reduced mast cell number, diminished IgE, TSLP, IL-4, and IL-13 levels, and peripheral blood Th2 cell content, with no significant changes in IFN-γ level. CQ alleviated type 2 inflammatory response in AD mice by inhibiting the activation of TLR3. CQ suppressed NLRP3 inflammasome activation. Activating TLR3/NLRP3 annulled CQ-mediated alleviation on type 2 inflammatory response in AD mice.

Conclusion

CQ alleviated type 2 inflammatory response in AD mice by inhibiting TLR3 activation and NLRP3 inflammasome activation.

Comparison of Pollutant Effects on Cutaneous Inflammasomes Activation

The skin is the outermost layer of the body and, therefore, is exposed to a variety of stressors, such as environmental pollutants, known to cause oxinflammatory reactions involved in the exacerbation of several skin conditions. Today, inflammasomes are recognized as important modulators of the cutaneous inflammatory status in response to air pollutants and ultraviolet (UV) light exposure. In this study, human skin explants were exposed to the best-recognized air pollutants, such as microplastics (MP), cigarette smoke (CS), diesel engine exhaust (DEE), ozone (O3), and UV, for 1 or 4 days, to explore how each pollutant can differently modulate markers of cutaneous oxinflammation. Exposure to environmental pollutants caused an altered oxidative stress response, accompanied by increased DNA damage and signs of premature skin aging. The effect of specific pollutants being able to exert different inflammasomes pathways (NLRP1, NLRP3, NLRP6, and NLRC4) was also investigated in terms of scaffold formation and cell pyroptosis. Among all environmental pollutants, O3, MP, and UV represented the main pollutants affecting cutaneous redox homeostasis; of note, the NLRP1 and NLRP6 inflammasomes were the main ones modulated by these outdoor stressors, suggesting their role as possible molecular targets in preventing skin disorders and the inflammaging events associated with environmental pollutant exposure.

Ubiquitination as a key regulatory mechanism for O3-induced cutaneous redox inflammasome activation

NLRP1 is one of the major inflammasomes modulating the cutaneous inflammatory responses and therefore linked to a variety of cutaneous conditions. Although NLRP1 has been the first inflammasome to be discovered, only in the past years a significant progress was achieved in understanding the molecular mechanism and the stimuli behind its activation. In the past decades a crescent number of studies have highlighted the role of air pollutants as Particulate Matter (PM), Cigarette Smoke (CS) and Ozone (O3) as trigger stimuli for inflammasomes activation, especially via Reactive Oxygen Species (ROS) mediators. However, whether NLRP1 can be modulated by air pollutants via oxidative stress and the mechanism behind its activation is still poorly understood. Here we report for the first time that O3, one of the most toxic pollutants, activates the NLRP1 inflammasome in human keratinocytes via oxidative stress mediators as hydrogen peroxide (H2O2) and 4-hydroxy-nonenal (4HNE). Our data suggest that NLRP1 represents a target protein for 4HNE adduction that possibly leads to its proteasomal degradation and activation via the possible involvement of E3 ubiquitin ligase UBR2. Of note, Catalase (Cat) treatment prevented inflammasome assemble and inflammatory cytokines release as well as NLRP1 ubiquitination in human keratinocytes upon O3 exposure. The present work is a mechanistic study that follows our previous work where we have showed the ability of O3 to induce cutaneous inflammasome activation in humans exposed to this pollutant. In conclusion, our results suggest that O3 triggers the cutaneous NLRP1 inflammasome activation by ubiquitination and redox mechanism.

From the Cochrane Library: Dietary Supplements for Established Atopic Eczema

Collapse

Protective Effect of Diet-Supplemented and Endogenously Produced Omega-3 Fatty Acids against HFD-Induced Colon Inflammation in Mice

Perilla (Perilla frutescens) oil reduces high-fat-diet-induced colon inflammation by suppressing the NF-κB pathway. In the current study, we compared the effect of endogenously produced and externally supplemented omega-3 fatty acids on high-fat-diet-induced colon inflammation. The fat-1 transgenic mice that endogenously synthesize omega-3 fatty acids were backcrossed with C57BL/6J wild-type mice to obtain transgenic (TR) and wild-type (WT) littermates. Five-week-old male littermates were divided into five groups: two groups fed 10% normal diet (WTLD, TRLD) and three groups fed with a 60% fat high-fat diet (WTHD, TRHD, and WTPO). In the WTPO group, 8% (w/w) of perilla oil was added. Perilla oil supplemented WT mice and fat-1 transgenic mice suppressed high-fat-diet-induced body weight and improved serum lipid levels. Furthermore, the WTPO and TRHD groups exhibited increased colon length, lower macroscopic scores, and reduced levels of pro-inflammatory markers and improved epithelial integrity barrier markers. The expression of GPR120 was increased in the WTPO group. Altogether, our results indicated that perilla oil could improve the symptoms of colon inflammation as an alternate omega-3 fatty acid supplement.

Sacran polysaccharide improves atopic dermatitis through inhibiting Th2 type immune response

AIMS

This study was aimed to explore whether sacran polysaccharide has a therapeutic effect on atopic dermatitis (AD) and its possible mechanisms.

MATERIALS AND METHODS

2, 4-dinitrochlorobenzene (DNCB)-induced AD mice were treated with 0.2% Sacran, 0.5% Sacran and 0.1% tacrolimus. Through scoring dermatitis severity, measuring ear thickness, cracking behavior, open field test, we evaluated the therapeutic effect of Sacran on DNCB-induced AD mice. CD4⁺ T cells and CD8⁺ T cells were evaluated by flow cytometry. The relative expression of Ifng and Il4 were measured by real-time quantitative PCR.

KEY FINDINGS

Sacran could relieved the symptoms of DNCB-induced AD mice, such as AD score, ear thickness, and IgE release. Sacran may alleviate dermatitis by inhibiting Th2 activation and reducing IgE release.

SIGNIFICANCE

Our research further proved that polysaccharide Sacran has anti-dermatitis effects, and also clarified its mechanism of alleviating dermatitis by inhibiting the activation of Th2 cells and reducing the release of IgE, which provides a theoretical basis for the future clinical transformation of polysaccharide Sacran.

The Complex Interplay between Immunonutrition, Mast Cells, and Histamine Signaling in COVID-19

There is an ongoing need for new therapeutic modalities against SARS-CoV-2 infection. Mast cell histamine has been implicated in the pathophysiology of COVID-19 as a regulator of proinflammatory, fibrotic, and thrombogenic processes. Consequently, mast cell histamine and its receptors represent promising pharmacological targets. At the same time, nutritional modulation of immune system function has been proposed and is being investigated for the prevention of COVID-19 or as an adjunctive strategy combined with conventional therapy. Several studies indicate that several immunonutrients can regulate mast cell activity to reduce the de novo synthesis and/or release of histamine and other mediators that are considered to mediate, at least in part, the complex pathophysiology present in COVID-19. This review summarizes the effects on mast cell histamine of common immunonutrients that have been investigated for use in COVID-19.

Mdivi-1 alleviates atopic dermatitis through the inhibition of NLRP3 inflammasome

Atopic dermatitis (AD) is a chronic inflammatory cutaneous disorder with few treatment options. Dynamin-related protein 1 (Drp1)-dependent mitochondrial fission contributes to the activation of NLRP3 inflammasome, and inhibiting Drp1 has been become an attractive therapeutic strategy for inflammatory diseases. This study aimed to investigate the effects of Drp1 inhibitor mdivi-1 on experimental AD. We firstly detected the effects of mdivi-1 on primary human keratinocytes in an inflammatory cocktail-induced AD-related inflammation in vitro. Results showed that mdivi-1 inhibited NLRP3 inflammasome activation and pyroptosis which were evidenced by decreased expression of NLRP3, ASC, cleavage of caspase-1, GSDMD-NT, mature interleukin (IL)-1β and IL-18 in keratinocytes under AD-like inflammation. Next, mouse model of AD-like skin lesions was induced by epicutaneous application of 2,4-dinitrochlorobenzene (DNCB) and mdivi-1 (25 mg/kg/day, days 5-33 during construction of AD model) was intraperitoneally injected into DNCB-induced mice. AD mice with mdivi-1 treatment exhibited ameliorated AD symptoms, lower serum IgE level, and reduced epidermal thickening, mast cells infiltration, and production of IL-4, IL-5 and IL-13 in the lesional tissues. Indeed, mdivi-1 significantly inhibited NLRP3 inflammasome activation and pyroptotic injury occurred in DNCB-treated skin tissues. Mechanically, mdivi-1 regulated the expression of mitochondrial dynamic proteins and suppressed the activation of NF-κB signal pathway which is an upstream of NLRP3 inflammasome both in vitro and in vivo. This study demonstrated that mdivi-1 could protect against experimental AD through inhibiting the activation of NLRP3 inflammasome and subsequent inflammatory cytokine release, and mdivi-1 might exert this function by inhibiting mitochondrial fission and subsequently blocking NF-κB pathway.

Clinical and Instrumental Exploration of Sensitive Skin in a Pediatric Population

Studies on sensitive skin pathophysiology in infants are challenging because most assessment methods require self-reporting of signs. In this study, we aimed to identify and characterize sensitive skin in children for the first time. A newly developed parent-reported questionnaire was used to recruit children with sensitive skin. This questionnaire was also tested on an adult group. Hydration, transepidermal water loss (TEWL), and inflammatory markers (cytokines, and polyunsaturated fatty acids (PUFAs)) were quantified. A total of 77 children and 20 adults (33 and 10 with sensitive skin, respectively) were recruited. The groups with sensitive skin had more clinical signs of skin dryness. Skin hydration was lower in children in the sensitive compared with the nonsensitive skin group. TEWL levels were similar between sensitive and nonsensitive subjects in both infant and adult groups. Sensitive skin exhibited higher levels of cytokines and proinflammatory PUFAs as well as lower levels of anti-inflammatory PUFAs. Sensitive skin syndrome was associated with normal skin barrier function but lower hydration in infants and children. The higher levels of proinflammatory markers suggest that sensitive skin is associated with low-level inflammation. It is hypothesized, for the first time, that PUFAs are involved in sensitive skin syndrome in infants.

Immunomodulatory diet in pediatric age

In the last few decades, the importance of a functioning immune system and health status has become more evident. Multiple factors are able to influence the development of chronic diseases and diet is one of the most important environmental factors. Evidence demonstrates that dietary patterns high in fat and low in fiber are associated with the development of non-communicable diseases. Moreover, optimal nutritional status can modulate immune maturation and response to inflammation. During inflammatory conditions, nutritional deficiencies may occur, establishing a vicious circle, consequently a balanced nutritional status is essential to prevent and counteract infections. Dietary diversity can prevent allergic diseases and nutrients such as DHA, arginine, vitamins and trace elements have an impact on physical barriers (such as gut mucosal barrier and skin), on the immune system response and on microbiome modulation. Protein deficiencies can compromise innate and adaptive immune functions; arginine availability can affect the immune response in injured states and other disease processes; EPA and DHA can modulate both innate and adaptive immunity; prebiotics have a beneficial effect on the functioning of the immune system. Zinc, copper, selenium and iron are involved in the correct development and function of the immune system. Vitamins D, E, A, B and C have a role on immune system through different mechanisms of action. Since a complex interplay exists between diet, microbiome and epigenetic factors which determine nutrient-induced changes on the immune function, the effect of each single nutrient may be difficult to study. Well-designed intervention studies, investigating the effects of whole dietary pattern, should be performed to clarify impact of foods on the immune function and disease risk.

Endogenous conversion of n-6 to n-3 polyunsaturated fatty acids facilitates the repair of cardiotoxin-induced skeletal muscle injury in fat-1 mice

In this study, we investigated the beneficial effects of high endogenous levels of n-3 polyunsaturated fatty acids (PUFAs) on skeletal muscle repair and regeneration using a mouse cardiotoxin (CTX, 20 μM/200 μL) -induced gastrocnemius muscle injury model. Transgenic fat-1 mice expressing the Caenorhabditis elegans fat-1 gene, encoding n-3 fatty acid desaturase, showed higher n-3 PUFA levels and lower n-6/n-3 PUFA ratios in gastrocnemius muscle tissues. Hematoxylin and eosin and Masson’s trichrome staining of gastrocnemius sections revealed increased muscle fiber size and reduced fibrosis in fat-1 mice on days 7 and 14 after CTX injections. Gastrocnemius muscle tissues from fat-1 mice showed reduced inflammatory responses and increased muscle fiber regeneration reflecting enhanced activation of satellite cells on day 3 after cardiotoxin injections. Gastrocnemius muscle tissues from cardiotoxin-treated fat-1 mice showed reduced levels of pro-apoptotic proteins (Caspase 3 and Bax) and increased levels of anti-apoptotic proteins (Bcl-2 and Survivin). Moreover, eicosapentaenoic acid (EPA) reduced the incidence of apoptosis among cardiotoxin-treated C2C12 mouse myoblasts. These findings demonstrate that higher endogenous n-3 PUFA levels in fat-1 mice enhances skeletal muscle repair and regeneration following cardiotoxin-induced injury.

Candida albicans and candidalysin in inflammatory disorders and cancer

As our understanding of mycology progresses, the impact of fungal microbes on human health has become increasingly evident. Candida albicans is a common commensal fungus that gives rise to local and systemic infections, particularly in immunocompromised patients where it can result in mortality. However, C. albicans has also been quietly linked with a variety of inflammatory disorders, to which it has traditionally been considered incidental; recent studies may now provide new aspects of these relationships for further consideration. This review provides a novel perspective on the impact of C. albicans and its peptide toxin, candidalysin, on human health, exploring their contributions to pathology within a variety of diseases.

Microneedles for painless transdermal immunotherapeutic applications

Immunotherapy has recently garnered plenty of attention to improve the clinical outcomes in the treatment of various diseases. However, owing to the dynamic nature of the immune system, this approach has often been challenged by concerns regarding the lack of adequate long-term responses in patients. The development of microneedles (MNs) has resulted in the improvement and expansion of immuno-reprogramming strategies due to the housing of high accumulation of dendritic cells, macrophages, lymphocytes, and mast cells in the dermis layer of the skin. In addition, MNs possess many outstanding properties, such as the ability for the painless traverse of the stratum corneum, minimal invasiveness, facile fabrication, excellent biocompatibility, convenient administration, and bypassing the first pass metabolism that allows direct translocation of therapeutics into the systematic circulation. These advantages make MNs excellent candidates for the delivery of immunological biomolecules to the dermal antigen-presenting cells in the skin with the aim of vaccinating or treating different diseases, such as cancer and autoimmune disorders, with minimal invasiveness and side effects. This review discusses the recent advances in engineered MNs and tackles limitations relevant to traditional immunotherapy of various hard-to-treat diseases.

Anti-inflammatory effects of Capparis ecuadorica extract in phthalic-anhydride-induced atopic dermatitis of IL-4/Luc/CNS-1 transgenic mice

CONTEXT

The natural products derived from Capparis ecuadorica H.H. Iltis (Capparaceae) could have great potential for anti-inflammation since they inhibited the inflammatory response in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells.

OBJECT

This study investigated the anti-inflammatory effects and related mechanism of methanol extract of C. ecuadorica leaves (MCE) during atopic dermatitis (AD) responses.

MATERIALS AND METHODS

Alterations in the phenotypical markers for AD, luciferase signal, iNOS-mediated COX-2 induction pathway, and inflammasome activation were analysed in non-Tg (n = 5) and 15% phthalic anhydride (PA) treated IL-4/Luc/CNS-1 transgenic (Tg) HR1 mice (n = 5 per group), subsequent to treatment with acetone-olive oil (AOO), vehicle (DMSO) and two dose MCE (20 and 40 mg/kg) three times a week for 4 weeks.

RESULTS

MCE treatment reduced the intracellular ROS level (48.2%), NO concentration (7.1 mmol/L) and inflammatory cytokine expressions (39.1%) in the LPS-stimulated RAW264.7 cells. A significant decrease was detected for ear thickness (16.9%), weight of lymph node (0.7 mg), IgE concentration (1.9 µg/mL), and epidermal thickness (31.8%) of the PA + MCE treated Tg mice. MCE treatment induced the decrease of luciferase signal derived from the IL-4 promoter and the recovery of the IL-4 downstream regulator cytokines. PA + MCE treated Tg mice showed decreasing infiltration of mast cells (42.5%), iNOS-mediated COX-2 induction pathway, MAPK signalling pathway and inflammasome activation in the ear tissue.

CONCLUSIONS

These findings provide the first evidence that MCE may have great potential to suppress chemical-induced skin inflammation through the suppression of IL-4 cytokine and the iNOS-mediated COX-2 induction pathway, and activation of inflammasome.

Poly-γ-Glutamate microneedles as transdermal immunomodulators for ameliorating atopic dermatitis-like skin lesions in Nc/Nga mice

Atopic dermatitis (AD), a common, relapsing, inflammatory disorder of the skin, is associated with T helper type 2 (Th2)-biased immune responses. Despite the efficacy of existing drugs for AD treatment, their safety and side effects cause concern. The present study describes the use of dissolvable poly-γ-glutamate (γ-PGA) microneedles (MNs) with immunomodulatory effects for effectively relieving AD-like symptoms in Nc/Nga mice. γ-PGA MNs can easily penetrate the epidermis and release γ-PGA into the dendritic cell-rich dermis to interact with dendritic cells for modulating immune responses. Transdermal administration of high-molecular-weight (HMW, 1100 kDa) γ-PGA MNs significantly reduced clinical dermatitis scores, epidermal thickness, and mast cell infiltration in mice by downregulating immunoglobulin (Ig)E and IgG1 levels (Th2-associated antibodies) compared with the AD control group. However, low-molecular-weight (200-400 kDa) γ-PGA MNs ameliorated AD-like skin lesions less effectively than HMW γ-PGA MNs, thus indicating that the MW of γ-PGA may affect its immunomodulatory properties. Notably, the mouse skin quickly recovered its barrier function within 4 h after MN application. No weight loss or abnormality was observed in the MN-treated mice during the 8-week treatment period. These results suggest that the γ-PGA MNs represent an innovative, safe, and reliable therapeutic strategy for AD management. STATEMENT OF SIGNIFICANCE: This study is the first to explore the feasibility of using poly-γ-glutamate (γ-PGA) microneedles (MNs) as transdermal immunomodulators for improving atopic dermatitis (AD) symptoms and to evaluate their immunomodulatory effect in mice with spontaneously developed AD. Transdermal administration of γ-PGA MNs enables the γ-PGA to localize in the skin for activation of dermal dendritic cells, thus modulating immune responses. We demonstrate that high-molecular-weight γ-PGA MNs can be retained in the skin for at least 6 days and effectively suppress AD-like skin lesions in mice by reducing infiltration of mast cells and downregulating Th2-associated antibody production (IgE and IgG1). The developed MN device has the potential to replace conventional therapy and to become an innovative treatment strategy for AD.

Allergy Modulation by N-3 Long Chain Polyunsaturated Fatty Acids and Fat Soluble Nutrients of the Mediterranean Diet

The Mediterranean diet, containing valuable nutrients such as n-3 long chain poly-unsaturated fatty acids (LCPUFAs) and other fat-soluble micronutrients, is known for its health promoting and anti-inflammatory effects. Its valuable elements might help in the battle against the rising prevalence of non-communicable diseases (NCD), including the development of allergic diseases and other (chronic) inflammatory diseases. The fat fraction of the Mediterranean diet contains bioactive fatty acids but can also serve as a matrix to dissolve and increase the uptake of fat-soluble vitamins and phytochemicals, such as luteolin, quercetin, resveratrol and lycopene with known immunomodulatory and anti-inflammatory capacities. Especially n-3 LCPUFAs such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) derived from marine oils can target specific receptors or signaling cascades, act as eicosanoid precursors and/or alter membrane fluidity and lipid raft formation, hereby exhibiting anti-inflammatory properties. Beyond n-3 LCPUFAs, fat-soluble vitamins A, D, E, and K1/2 have the potential to affect pro-inflammatory signaling cascades by interacting with receptors or activating/inhibiting signaling proteins or phosphorylation in immune cells (DCs, T-cells, mast cells) involved in allergic sensitization or the elicitation/effector phase of allergic reactions. Moreover, fat-soluble plant-derived phytochemicals can manipulate signaling cascades, mostly by interacting with other receptors or signaling proteins compared to those modified by fat-soluble vitamins, suggesting potential additive or synergistic actions by applying a combination of these nutrients which are all part of the regular Mediterranean diet. Research concerning the effects of phytochemicals such as polyphenols has been hampered due to their poor bio-availability. However, their solubility and uptake are improved by applying them within the dietary fat matrix. Alternatively, they can be prepared for targeted delivery by means of pharmaceutical approaches such as encapsulation within liposomes or even unique nanoparticles. This review illuminates the molecular mechanisms of action and possible immunomodulatory effects of n-3 LCPUFAs and fat-soluble micronutrients from the Mediterranean diet in allergic disease development and allergic inflammation. This will enable us to further appreciate how to make use of the beneficial effects of n-3 LCPUFAs, fat-soluble vitamins and a selection of phytochemicals as active biological components in allergy prevention and/or symptom reduction.

Para-phenylenediamine, an oxidative hair dye ingredient, increases thymic stromal lymphopoietin and proinflammatory cytokines causing acute dermatitis

Due to high consumption of cosmetics in modern society, people are always exposed to the risk of skin damage and complications. Para-phenylenediamine (P-PD), an ingredient of hair dye, has been reported to cause allergic contact dermatitis. However, the mechanism has not been well elucidated. Here, we identify that P-PD causes dermatitis by increasing thymic stromal lymphopoietin (TSLP) and inflammatory cytokines. Topical application of P-PD to mouse ear skin in consecutive 5 days resulted in dermatitis symptoms and increased ear thickness. TSLP production in skin was upregulated by P-PD treatment alone. In addition, P-PD-induced TSLP production was potentiated by MC903, which is an in vivo TSLP inducer. P-PD increased TSLP production in keratinocytes (KCMH-1 cells and phorbol 12-myristate 13-acetate-stimulated PAM212 cells). The production of proinflammatory cytokines such as IL-1β, IL-6, IFN-γ, and CCL2, was upregulated by P-PD treatment together with MC903. The results show that repeated exposure to P-PD causes acute contact dermatitis mediated by increasing the expression of TSLP and proinflammatory cytokines.

Effects of Omega-3 Fatty Acids on Immune Cells

Alterations on the immune system caused by omega-3 fatty acids have been described for 30 years. This family of polyunsaturated fatty acids exerts major alterations on the activation of cells from both the innate and the adaptive immune system, although the mechanisms for such regulation are diverse. First, as a constitutive part of the cellular membrane, omega-3 fatty acids can regulate cellular membrane properties, such as membrane fluidity or complex assembly in lipid rafts. In recent years, however, a new role for omega-3 fatty acids and their derivatives as signaling molecules has emerged. In this review, we describe the latest findings describing the effects of omega-3 fatty acids on different cells from the immune system and their possible molecular mechanisms.

In vitro expression of NLRP inflammasome-induced active Caspase-1 expression in normal human epidermal keratinocytes (NHEK) by various exogenous threats and subsequent inhibition by naturally derived ingredient blends

Background

The discovery of the nod-like receptor protein (NLRP) inflammasomes in 2002 has led to the rapid identification of these unique cellular proteins as key targets for studies on innate inflammation pathways. The NLRP inflammasomes have been shown to be expressed in normal human epidermal keratinocytes (NHEK) and human dermal fibroblasts (HDF). NLRP inflammasomes in keratinocytes are interesting as these skin cells are the first living cells in the skin to contact external exogenous threats such as UV energy, chemicals, physical trauma, and bacteria and viruses. Activation of the NLRP Inflammasomes by exogenous threats results in the release of active Caspase-1 (ACasp-1), a key protease enzyme, which targets inactive forms of IL-1β, IL-18 as well as IL-1α and IL-33.

Purpose

This article discusses efforts to examine the release of active Caspase-1 from NHEKs activated by various exogenous threats including UVB energy, ATP, Nigericin and Urban Dust. The work further examines if, after inflammasome activation and Caspase-1 release, certain naturally derived botanical ingredients known to have anti-inflammatory effects can function to inhibit upregulation of active Caspase-1.

Methods

NHEK were treated with various doses of UVB, ATP and Nigericin and with a single dose of Urban Dust. ACasp-1 expression was measured after 3 and 20 hours using the Promega Caspase Glo-1 bioluminescent assay. After confirmation that 60 mJ/cm² of UVB and 5mM of ATP were effective to activate NHEK ACasp-1 release after 20 hrs, these conditions were employed to examine the influence of three botanical blends of ingredients on their ability to inhibit ACasp-1 expression.

Results

Initial results demonstrate that NHEKs can be activated to release active Caspase-1 by ATP and UVB, but not by Nigericin or Urban Dust. In addition, it was unexpectedly found that, while ATP and UVB activated NHEKs, the release of ACasp-1-did not happen within the first 3 hours after exposure but did become significant after 20 hours. Additional results indicate that a blend of polysaccharides and two blends of antioxidants, one oil-soluble and the other water-soluble, known for their anti-inflammatory effects, can reduce expression of active Caspase-1 in activated NHEKs when applied extracellularly.

Conclusion

Expression of NLRP activated release of ACasp-1 was found to be influenced by UVB and ATP but not by Nigericin or Urban Dust. The effects were also time dependent. Several botanical extract blends were found to reduce ACasp-1 expression in previously activated NHEKs. Links between these inflammatory effects and processes of cellular inflammaging are discussed.