Cicadidae Periostracum Attenuates Atopic Dermatitis Symptoms and Pathology via the Regulation of NLRP3 Inflammasome Activation

The role of NLRP3 inflammasome in type 2 inflammation related diseases

Type 2 inflammation related diseases, such as atopic dermatitis, asthma, and allergic rhinitis, are diverse and affect multiple systems in the human body. It is common for individuals to have multiple co-existing type 2 inflammation related diseases, which can impose a significant financial and living burden on patients. However, the exact pathogenesis of these diseases is still unclear. The NLRP3 inflammasome is a protein complex composed of the NLRP3 protein, ASC, and Caspase-1, and is activated through various mechanisms, including the NF-κB pathway, ion channels, and lysosomal damage. The NLRP3 inflammasome plays a role in the immune response to pathogens and cellular damage. Recent studies have indicated a strong correlation between the abnormal activation of NLRP3 inflammasome and the onset of type 2 inflammation. Additionally, it has been demonstrated that suppressing NLRP3 expression effectively diminishes the inflammatory response, highlighting its promising therapeutic applications. Therefore, this article reviews the role of NLRP3 inflammasome in the development and therapy of multiple type 2 inflammation related diseases.

Pyroptosis and its role in autoimmune skin disease

Autoimmune skin disease is a kind of heterogeneous disease with complicated pathogenesis. Many factors such as genetic, infectious, environmental and even psychological factors may interact together to trigger a synergistic effect for the development of abnormal innate and adaptive immune responses. Although the exact mechanisms remain unclear, recent evidence suggests that pyroptosis plays a pivotal role in the development of autoimmune skin disease. The feature of pyroptosis is the first formation of pores in cellular membranes, then cell rupture and the release of intracellular substances and pro-inflammatory cytokines, such as interleukin-1 beta (IL-1β) and IL-18. This hyperactive inflammatory programmed cell death damages the homeostasis of the immune system and advances autoimmunity. This review briefly summarises the molecular regulatory mechanisms of pyrin domain-containing protein 3 (NLRP3) inflammasome and gasdermin family, as well as the molecular mechanisms of pyroptosis, highlights the latest progress of pyroptosis in autoimmune skin disease, including systemic lupus erythematosus, psoriasis, atopic dermatitis and systemic scleroderma and attempts to identify its potential advantages as a therapeutic target or prognostic biomarker for these diseases.

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.

Icariin restrains NLRP3 inflammasome-mediated Th2 immune responses and ameliorates atopic dermatitis through modulating a novel lncRNA MALAT1/miR-124-3p axis

CONTEXT

Atopic dermatitis (AD) is a common inflammatory skin disease characterized with hyperactivation of type 2 T helper (Th2) immune responses. Icariin is a flavonoid glucoside with anti-inflammatory activities, which has been used to treat multiple diseases.

OBJECTIVE

The present study investigates the underlying mechanisms by which icariin regulates Th2 responses and AD development.

MATERIALS AND METHODS

BALB/c mice were induced by DNFB to establish AD models, and injected with or without 10 mg/kg icariin for 2 weeks (i.p., daily). CD4+T cells were induced by Th2 condition to simulate AD in vitro, and also treated with or without 100 µM icariin.

RESULTS

Icariin ameliorated AD-like skin lesion, manifested as a significant decrease in dermatitis scores (from 8.00 ± 1.00 to 3.67 ± 0.58), serum IgE levels (from 3119.15 ± 241.81 to 948.55 ± 182.51 ng/mL), epidermal thickness (from 93.86 ± 4.61 to 42.67 ± 2.48 µm) and infiltration of mast cells (from 60.67 ± 3.21 cells to 36.00 ± 2.65 cells). Also, icariin inactivated NLRP3 inflammasome, inhibited Th2 skewing, reduced lncRNA MALAT1 expression, but elevated miR-124-3p expression in vivo and in vitro. MALAT1 increased NLRP3 expression through targeting miR-124-3p. Knockdown of MALAT1 repressed NLRP3 inflammasome activation and mitigated Th1/Th2 imbalance in Th2-conditioned CD4+T cells, whereas both MALAT1 overexpression and miR-124-3p inhibition ablated the inhibitory effects of icariin on Th2 immune responses.

DISCUSSION AND CONCLUSIONS

The findings further improve our understanding of the mechanism by which icariin affects AD progression, and highlights the potential of icariin in the treatment of AD.

Esculentoside A ameliorates DNCB-induced atopic dermatitis by suppressing the ROS-NLRP3 axis via activating the Nrf2 pathway

Atopic dermatitis (AD) is a chronic inflammatory skin condition with a high prevalence. Inflammation and oxidative stress are strongly associated with AD progression. Esculentoside A (EsA) inhibits inflammation and oxidative stress in various diseases. However, whether EsA mitigates AD by suppressing inflammation and oxidative stress remains unknown. A mouse model of AD was constructed by the induction of 1-chloro-2,4-dinitrochlorobenzene (DNCB). The mechanism of EsA and its effects on AD symptoms, pathology, inflammation and oxidative stress were investigated through histopathological staining, enzyme-linked immunosorbent assay, blood cells analysis, colorimetric measurement and western blot analysis. EsA improved the clinical symptoms and increased clinical skin scores in AD mice. Skin thickening of the epidermis and dermal tissues and the mast cell numbers in AD mice were reduced with the EsA treatment. EsA decreased the relative mRNA level of thymic stromal lymphopoietin, interleukin (IL)-4, IL-5 and IL-13; the serum concentrations of immunoglobulin E (IgE) and IL-6; and the numbers of white blood cells (WBC) and WBC subtypes, including basophil, lymphocytes, eosinophil, neutrophil and monocytes in DNCB-induced mice. DNCB caused higher levels of oxidative stress, which was reversed with the administration of EsA. Mechanically, EsA upregulated the expression of Nrf2 but downregulated the level of NLRP3 inflammasome in AD mice. The inhibitor of Nrf2 significantly recovered the EsA-induced changes in the NLRP3 inflammasome proteins in DNCB-treated mice. Therefore, EsA improved the clinical and pathological symptoms, inflammation and oxidative stress experienced by DNCB-induced mice and was involved in the inactivation of NLRP3 inflammasome by activating Nrf2.

The Slough of Cicadidae Periostracum Ameliorated Lichenification by Inhibiting Interleukin (IL)-22/Janus Kinase (JAK) 1/Signal Transducer and Activator of Transcription (STAT) 3 Pathway in Atopic Dermatitis

It is known that animal-origin medicine could be one of effective treatment to remedy atopic dermatitis (AD) by controlling the cytokines. Cicadidae Periostracum (CP), the slough of Cryptotympana pustulata, has been frequently used for treating AD and skin affliction in traditional Korean Medicine. This study is aimed at investigating the ameliorating effects of CP on AD and its potential mechanism. The dinitrochlorobenzene sensitized mice were treated with CP for 2 weeks. The various biomarkers and the dermatitis scores presented that CP treatment can induce the visual and biological improvements of AD model. Pruritus, the most serious symptom of AD, which can cause repeated scratching behaviors and finally lead to lichenification, was reduced with CP treatment by regulating the inflammatory reactions. In addition, CP treatment diminished the number of mast cells that are known for causing inflammatory reactions. Moreover, it is proven that CP can decline secretion of interleukin-22, which means CP treatment has anti-inflammatory effects. CP treatment can correct the imbalance of helper T (Th)1 and Th2, downregulating thymic stromal lymphopoietin that leads to decrease of mRNA level of inflammatory cytokines. The crucial role of CP treatment is controlling of the Janus kinase 1/signal transducer and activator of transcription 3 pathway. In addition, CP treatment has the inhibitory effects on kallikrein related peptidase (KLK) 5 and KLK7. Taken together, CP treatment can ameliorate most symptoms and problems caused by AD disease, improving the AD patients' life quality.

Tenebrio molitor Larva Trypsin Hydrolysate Ameliorates Atopic Dermatitis in C57BL/6 Mice by Targeting the TLR-Mediated MyD88-Dependent MAPK Signaling Pathway

Atopic dermatitis (AD) is a widely researched chronic inflammatory skin disease with a complex etiology. The increased prevalence of AD necessitates exploration of natural sources as potential therapeutic agents with limited side effects. In the current study, a 1-chloro-2,4-dinitrobenzene (DNCB)-induced AD mouse model was used to examine the anti-AD effects of Tenebrio molitor trypsin hydrolysate (TMTH) and its underlying molecular mechanism. DNCB-treated mice were treated with TMTH (1 and 10 mg/kg), and prednisolone (3 mg/kg) was used as the positive control. Serum and skin tissue samples were collected for subsequent analyses. The expression levels of proteins linked to the myeloid differentiation primary response 88 (MyD88)-dependent mitogen-activated protein kinase (MAPK) signaling pathway and serum IgE levels were estimated via Western blotting technique and ELISA (enzyme-linked immunosorbent assay), respectively. Inflammatory cell infiltration and thickening of the dorsal skin were measured using toluidine blue and hematoxylin and eosin staining, respectively. Oral administration of TMTH significantly reduced mast cell infiltration and dermal and epidermal thickness. Moreover, TMTH treatment reduced serum IgE levels. Western blotting confirmed that TMTH treatment suppressed the MyD88-dependent MAPK signaling pathway. Therefore, TMTH substantially inhibited AD-like skin lesion formation via immunomodulation, showing considerable potential for AD treatment.

Clinical Efficacy and Safety of Chinese Herbal Medicine in the Treatment of Uremic Pruritus: A Meta-Analysis of Randomized Controlled Trials

Uremic pruritus is a disturbing and refractory symptom in patients with advanced chronic kidney disease. Chinese herbal medicine has been reported to alleviate uremic pruritus. To investigate the effects of Chinese herbal medicine, we conducted a systematic review and meta-analysis on patients with uremic pruritus. We searched databases (prior to 3 May 2022) for randomized controlled trials on the effects of Chinese herbal medicine in treating uremic pruritus. Our meta-analysis included 3311 patients from 50 randomized controlled trials. In patients with uremic pruritus, adjunctive Chinese herbal medicine significantly improved overall effectiveness (risk ratio 1.29, 95% CI 1.23 to 1.35), quality of life, renal function, reduced pruritus score, and inflammatory biomarkers compared to control groups with hemodialysis alone or with anti-pruritic treatments. Chinese herbal medicine treatment showed a time-dependent tendency in improving the visual analog scale of dialysis patients. Compared to control groups, no significantly higher risk of adverse events in patients taking Chinese herbal medicine (risk ratio 0.60, 95% CI 0.22 to 1.63). Chinese herbal medicine appears to be effective and safe in complementing the treatment of patients with uremic pruritus.

Epimedin A ameliorates DNFB-induced allergic contact dermatitis in mice: Role of NF-κB/NLRP3-driven pyroptosis, Nrf2/HO-1 pathway, and inflammation modulation

AIMS

The present study aimed to investigate the potential of epimedin A to ameliorate DNFB-induced allergic contact dermatitis (CD) and reveal its potential underlying mechanisms of action, emphasizing its role in modulating NF-κB/NLRP3, Nrf2/HO-1 pathways, and inflammation.

MAIN METHODS

Seven-week-old BALB/c mice received epimedin A orally for 11 days at doses of 5, 10, or 20 mg/kg/day, starting from the seventh day of DNFB-inducing CD.

KEY FINDINGS

Epimedin A dose-dependently ameliorated DNFB-induced CD, as revealed by the repression of the mice's scratching behavior, dermatitis score, ear thickness and weight, and ear tissue's histopathological changes, and area percent of collagen fibers induced by DNFB. These potentials were due to the NF-κB/NLRP3 pathway suppression and the Nrf2 pathway enhancement, as demonstrated by the reduction of NF-κB, NLRP3, ASC, caspase-1, and 8 mRNA expression, and NF-κBp65, IL-1β, MDA levels, and NF-κBp65 binding activity, along with the enhancement of the Nrf2, HO-1, IκB-α, GSH levels, SOD activity, and Nrf2 binding activity. Besides, it suppressed ear tissues' NLRP3 and caspase-8 induced pyroptosis by suppressing the ear tissues' caspase-1, 8, GSDMD upregulation, and LDH activity. Additionally, it repressed the local inflammatory reaction of ear tissue, as evidenced by the reduction of the elevated inflammatory cytokines (IL-1β, IL-6, Il-4, TNF-α, and IFN-γ), the serum level of t-IgE, DNFB s-IgE, s-IgE/t-IgE ratio, and the abrogation of the ear tissues histopathological changes.

SIGNIFICANCE

Epimedin A is a novel, hopeful, natural therapeutic agent for CD by modulating NF-κB/NLRP3, Nrf2 pathways, and inflammation.

Angelica Yinzi alleviates 1-chloro-2,4-dinitrobenzene-induced atopic dermatitis by inhibiting activation of NLRP3 inflammasome and down-regulating the MAPKs/NF-kB signaling pathway

Background

Atopic dermatitis (AD), characterized by eczema as a chronic pruritic inflammatory skin disease, has become a serious health problem with recurrent clinical episodes. However, current clinical treatments have limited relief and are accompanied by adverse effects. Therefore, there is a necessity to develop new effective drugs for AD treatment. Angelica Yinzi (AYZ) is a classic ancient prescription for nourishing blood, moistening dryness, dispelling wind, and relieving itching. However, its mechanism for alleviating atopic dermatitis remains unknown. Therefore, this study aimed at determining the effects of AYZ and its potential mechanism in alleviating AD-like symptoms.

Methods

In the present study, we used 1-chloro-2,4-dinitrobenzene (DNCB) to establish a mouse model of atopic dermatitis, where DNCB readily penetrates the epidermis to cause inflammation. Histopathological analysis was performed to examine the thickening of dorsal skin and infiltration in the inflammatory and mast cells in C57BL/6 mice. Additionally, the immunoglobulin E (IgE) levels in serum were determined by enzyme-linked immunosorbent assay (ELISA) kits. The IL-1β and TNF-α expression were detected using qRT-PCR. Next, the Western blotting and immunohistochemistry assays were performed to assess the contribution of MAPKs/NF-κB signaling pathways and the NLRP3 inflammasome in AD responses.

Results

Histopathological examination revealed that AYZ reduced the epidermal thickness of AD-like lesioned skin and repressed the infiltration of mast cells into AD-like lesioned skin. AYZ significantly decreased the phosphorylation of p38 MAPK, JNK, ERK and NF-κB and downregulated serum IgE levels and IL-1β and TNF-α mRNA levels. Additionally, the NLRP3, ASC, Caspase-1, and IL-1β expression in dorsal skin were effectively down-regulated following AYZ treatment (p < 0.05 and p < 0.01).

Conclusion

These findings revealed that AYZ effectively suppressed AD-induced skin inflammation by inhibiting the activation of the NLRP3 inflammasome and the MAPKs/NF-kB signaling. Therefore, AYZ is a potential therapeutic agent against AD in the clinical setting.

Anti-Inflammatory Effects of Cicadidae Periostracum Extract and Oleic Acid through Inhibiting Inflammatory Chemokines Using PCR Arrays in LPS-Induced Lung inflammation In Vitro

In this study, we aimed to evaluate the anti-inflammatory effects and mechanisms of CP and OA treatments in LPS-stimulated lung epithelial cells on overall chemokines and their receptors using PCR arrays. In addition, we aimed to confirm those effects and mechanisms in LPS-stimulated lung macrophages on some chemokines and cytokines. In our study, CP treatments significantly inhibited the inflammatory mediators CCL2, CCL3, CCL4, CCL5, CCL6, CCL9, CCL11, CCL17, CCL20, CXCL1, CXCL2, CXCL3, CXCL5, CXCL7, CXCL10, TNF-α, and IL-6, while markedly suppressing NF-κB p65 nuclear translocation and the phosphorylations of PI3K p55, Akt, Erk1/2, p38, and NF-κB p65 in LPS-stimulated lung epithelial cells. CP treatments also significantly decreased the inflammatory mediators CCL2, CCL5, CCL17, CXCL1, and CXCL2, while markedly inhibiting phospho-PI3K p55 and iNOS expression in LPS-stimulated lung macrophages. Likewise, OA treatments significantly suppressed the inflammatory mediators CCL2, CCL3, CCL4, CCL5, CCL8, CCL11, CXCL1, CXCL3, CXCL5, CXCL7, CXCL10, CCRL2, TNF-α, and IL-6, while markedly reducing the phosphorylations of PI3K p85, PI3K p55, p38, JNK, and NF-κB p65 in LPS-stimulated lung epithelial cells. Finally, OA treatments significantly inhibited the inflammatory mediators CCL2, CCL5, CCL17, CXCL1, CXCL2, TNF-α, and IL-6, while markedly suppressing phospho-PI3K p55, iNOS, and Cox-2 in LPS-stimulated lung macrophages. These results prove that CP and OA treatments have anti-inflammatory effects on the inflammatory chemokines and cytokines by inhibiting pro-inflammatory mediators, including PI3K, Akt, MAPKs, NF-κB, iNOS, and Cox-2. These findings suggest that CP and OA are potential chemokine-based therapeutic substances for treating the lung and airway inflammation seen in allergic disorders.

Cera Flava Alleviates Atopic Dermatitis by Activating Skin Barrier Function via Immune Regulation

Cera Flava (CF), a natural extract obtained from beehives, is widely used in dermatological products owing to its wound healing, wrinkle reduction, UV-protective, and skin cell turnover stimulation effects. However, its effect on AD-like skin lesions is unknown. In this study, we used a mouse model of AD to evaluate the effects of CP at the molecular and phenotypic levels. Topical house dust mite (HDM) sensitization and challenge were performed on the dorsal skin of NC/Nga mice to induce AD-like cutaneous lesions, phenotypes, and immunologic responses. The topical application of CF for 6 weeks relieved HDM-induced AD-like phenotypes, as quantified by the dermatitis severity score, scratching frequency, and skin moisture. CP decreased immunoglobulin E, histamine, and thymic stromal lymphopoietin levels. Histopathological analysis showed that CF decreased epidermal thickening and the number of mast cells. CF attenuated HDM-induced changes in the expression of skin barrier-related proteins. Furthermore, CF decreased the mRNA levels of inflammatory factors, including interleukin (IL)-1β, IL-4, IL-13, IL-8, TARC, MDC, and RANTES, in dorsal skin tissue via the TLR2/MyD88/TRAF6/ERK pathway. CF influences skin barrier function and immune regulation to alleviate AD symptoms. It may therefore be an effective alternative to topical steroids for the treatment of AD.