Anti-inflammatory effect of galectin-1 in a murine model of atopic dermatitis

Regulatory role of annexin A1 in NLRP3 inflammasome activation in atopic dermatitis: insights from keratinocytes in human and murine studies

Despite the well-documented regulatory role of annexin A1 (ANXA1) in numerous stages of the inflammatory response, its involvement in regulating the NLRP3 inflammasome in the context of allergic responses has not been extensively investigated to date. This study evaluated the expression patterns of the ANXA1 and NLRP3 proteins in human skin samples obtained from patients with atopic dermatitis (AD) and in mice with ovalbumin (OVA)-induced experimental AD. Furthermore, the in vitro effect of the ANXA1 mimetic peptide Ac2-26 on IL-4-stimulated human keratinocytes was evaluated. IL-4-stimulated keratinocytes were treated with Ac2-26 (a mimetic peptide of ANXA1) in two different concentrations: 5 and 25 ng/mL. Additionally, some cells were treated with the pan-formyl peptide receptor antagonist Boc2 at a concentration of 10 µM, administered 15 min before Ac2-26. The NLRP3 protein demonstrated intense immunoreactivity in both murine and human AD skin samples, with NLRP3 and ANXA1 exhibiting particularly high coexpression in keratinocytes. A significant increase in ANXA1 and NLRP3 transcripts was observed in AD skins (GSE16161 study). ANXA1 transcript levels were elevated in the AD epidermis relative to the non-lesional epidermis, while NLRP3 transcript levels were reduced in the AD epidermis (GSE120721 study). The Ac2-26 treatment reduced the proliferation rate of IL-4-stimulated keratinocytes, an effect abolished by Boc2 and IL-1β and ROS production. In conclusion, our findings indicate that ANXA1 plays a role in regulating NLRP3 activation in keratinocytes, contributing to the pathogenesis of AD. KEY MESSAGES: ANXA1 and NLRP3 levels are upregulated and exhibit coexpression in murine and human AD skins. ANXA1-FPR axis regulates the proliferation of human keratinocytes under IL-4 stimulation. ANXA1-derived peptide Ac2-26 regulates oxidative stress and NLRP3 activation in human keratinocytes.

Neutrophils in Atopic Dermatitis

Neutrophils have a critical role in inflammation. Recent studies have identified their distinctive presence in certain types of atopic dermatitis (AD), yet their exact function remains unclear. This review aims to compile studies elucidating the role of neutrophils in AD pathophysiology. Proteins released by neutrophils, including myeloperoxidase, elastase, and lipocalin, contribute to pruritus progression in AD. Neutrophilic oxidative stress and the formation of neutrophil extracellular traps may further worsen AD. Elevated neutrophil elastase and high-mobility group box 1 protein expression in AD patients' skin exacerbates epidermal barrier defects. Neutrophil-mast cell interactions in allergic inflammation steer the immunological response toward Th2 imbalance and activate the Th17 pathway, particularly in response to allergens or infections linked to AD. Notably, drugs alleviating pruritic symptoms in AD inhibit neutrophilic inflammation. In conclusion, these findings underscore that neutrophils may be therapeutic targets for AD symptoms, emphasizing their inclusion in AD treatment strategies.

Exogenous drug-induced mouse models of atopic dermatitis

Atopic dermatitis (AD) is an inflammatory skin disease characterized by intense pruritus. AD is harmful to both children and adults, but its pathogenic mechanism has yet to be fully elucidated. The development of mouse models for AD has greatly contributed to its study and treatment. Among these models, the exogenous drug-induced mouse model has shown promising results and significant advantages. Until now, a large amount of AD-related research has utilized exogenous drug-induced mouse models, leading to notable advancements in research. This indicates the crucial significance of applying such models in AD research. These models exhibit diverse characteristics and are highly complex. They involve the use of various strains of mice, diverse types of inducers, and different modeling effects. However, there is currently a lack of comprehensive comparative studies on exogenous drug-induced AD mouse models, which hinders researchers' ability to choose among these models. This paper provides a comprehensive review of the features and mechanisms associated with various exogenous drug-induced mouse models, including the important role of each cytokine in AD development. It aims to assist researchers in quickly understanding models and selecting the most suitable one for further investigation.

Proteomic changes related to actin cytoskeleton function in the skin of vildagliptin-treated mice

BACKGROUND

Vildagliptin, a dipeptidyl peptidase-4 inhibitor (DPP-4i) is a widely used type 2 diabetes medication that is associated with an up-to 10-fold increased risk for the development of bullous pemphigoid (BP), an autoimmune skin disease. The mechanism by which vildagliptin promotes the development of BP remains unknown.

OBJECTIVE

To elucidate effects of vildagliptin treatment on the mouse cutaneous proteome.

METHODS

We analyzed the cutaneous proteome of nondiabetic mice treated for 12 weeks with vildagliptin using label-free shotgun mass spectrometry (MS), two-dimensional difference gel electrophoresis (2D-DIGE), immunohistochemistry, immunoblotting, and quantitative real-time polymerase chain reaction.

RESULTS

Although vildagliptin treatment did not cause any clinical signs or histological changes in the skin, separate MS and 2D-DIGE analyses revealed altered cutaneous expression of several proteins, many of which were related to actin cytoskeleton remodeling. Altogether 18 proteins were increased and 40 were decreased in the vildagliptin-treated mouse skin. Both methods revealed increased levels of beta-actin and C->U-editing enzyme APOBEC2 in vildagliptin-treated mice. However, elevated levels of a specific moesin variant in vildagliptin-treated animals were only detected with 2D-DIGE. Immunohistochemical staining showed altered cutaneous expression of DPP-4, moesin, and galectin-1. The changed proteins detected by MS and 2D-DIGE were linked to actin cytoskeleton remodeling, transport, cell movement and organelle assembly.

CONCLUSION

Vildagliptin treatment alters the cutaneous proteome of nondiabetic mice even without clinical signs in the skin. Cytoskeletal changes in the presence of other triggering factors may provoke a break of immune tolerance and further promote the development of BP.

Evaluation of Plasma Concentrations of Galectins-1, 2 and 12 in Psoriasis and Their Clinical Implications

Psoriasis is a complex disease that nowadays is considered not only a dermatosis but a kind of systemic disorder associated with many accompanying diseases. Metabolic complications leading to cardiovascular incidences are the cause of increased mortality in psoriatic patients. Galectins (gal) are beta-galactoside-binding lectins that exert different functions, including engagement in metabolic processes. Our aim was to assess the concentrations of gal-1, 2 and 12 in psoriatics, to establish their potential clinical implications, including in metabolic complications. Plasma galectins were assessed by ELISA in 60 psoriatic patients and 30 controls without dermatoses and a negative family history of psoriasis. Plasma concentrations of all galectins were significantly higher in patients than controls (gal-1 with p < 0.001, gal-2 and 12 with p < 0.05). There were no correlations between galectins concentrations and psoriasis severity in PASI or disease duration (p > 0.05). Gal-1 and 12 were significantly negatively correlated with GFR (p < 0.05, p < 0.01, respectively) and gal-2 with HDL (p < 0.05). Gal-2 was significantly positively correlated with CRP (p < 0.05) and gal-12 with fasting glucose (p < 0.01). Based on the results and given the reported role of galectins in metabolic disorders we may conclude that gal-1, 2 and 12 could be potentially engaged in metabolic complications in psoriatics, most probably in atherosclerosis. Gal-2 could be perhaps further investigated as a marker of metabolically induced inflammation in psoriasis, gal-1 and gal-12 as predictors of renal impairment in psoriatics due to metabolic disorders. Potentially, gal-12 could be considered in the future as a marker of carbohydrate metabolism disorders in psoriatics.

Therapeutic action of Kushen recipe extractive and its inhibitory effect on eotaxin in mouse models with contact dermatitis

BACKGROUND

Treatment of skin allergic diseases remains a challenging research topic.

OBJECTIVE

To investigate the effect of Kushen recipe extractive (KS) gel on contact dermatitis (CD) of mouse.

METHODS

Allergic contact dermatitis (ACD) model of mouse was established. Immunohistochemical method (ICH) and flow cytometry method (FCM) were used to detect CD4⁺ and CD8⁺ T lymphocytes and explore the regulation effect of KS on the immune status of the organism. The expression status of eotaxin tissue was evaluated by real-time polymerase chain reaction (RT-PCR), ICH, and western blotting method. The survival rates of HaCaT cell and Fibroblasts affected by KS were detected by methyl thiazolyl tetrazolium (MTT) method. The inhibitory effect of KS on eotaxin produced by HaCaT cell and FBs induced by TNF-α and interleukin (IL)-4 were evaluated using RT-PCR and enzyme-linked immunosorbent assay methods. The inhibitory effect of KS on nuclear factor-κB (NF-κB) and Signal transducers and activators of transcription 6 (STAT6) activation induced by TNF-α and IL-4 was detected by electrophoretic mobility shift assay and western blotting methods.

RESULTS

We confirmed that KS shows favorable therapeutic effect on CD, which can obviously inhibit eotaxin expression and Eosinophils recruitment in allergic skin of mouse, as well as regulate the immune status of the organism. Furthermore, KS and its main effective components can inhibit TNF-α and IL-4 induced upregulation of eotaxin via the two signal transduction pathways, NF-κB and STAT6.

CONCLUSIONS

The great importance of traditional Chinese recipe KS is evidenced by its therapeutic effect and mechanism in ACD of mouse.

Paraquat Induces Lung Injury via miR-199-Mediated SET in a Mouse Model

Objective: To explore the molecular mechanism of lung injury caused by paraquat (PQ) poisoning by investigating miR-199-mediated SET.

Methods: A paraquat poisoning model was established in C57BL/6 male mice via intraperitoneal injection of paraquat. The mice were transfected with miR-199 siRNA and or mimic. After 14 days of treatment, pathophysiological changes of the lung were observed and lung tissue was analyzed via Hematoxylin-Eosin staining. The levels of miR-199, SETs, surfactant protein SP-A and SP-B, and inflammatory and oxidative factors were analyzed by qPCR, Western Blot, and ELISA kits.

Results: A acute lung-injury (ALI) model was established using PQ treatment and confirmed with edema of pulmonary endothelium with low electronic density of endothelial cytoplasm, presence of protein-rich fluid, and numerous erythrocytes in alveolar space, concentric figures of damaged tubular myelin, alveolar destruction, and increase in inflammatory cell numbers. Compared with the control group, miR-199 and SET levels were reduced in the PQ-treated group. miR-199 siRNA increased the SET level, inflammatory and oxidative levels, and reduced the levels of SP-A and SP-B, and miR-199 mimic reduced the SET level, inflammatory and oxidative levels, and increased the levels of SP-A and SP-B. PQ treatment reduced miR-199 level.

Conclusion: Paraquat induces ALI by affecting miR-199-mediated SET.

Expression Pattern and Immunoregulatory Roles of Galectin-1 and Galectin-3 in Atopic Dermatitis and Psoriasis

The pathogenesis of atopic dermatitis (AD) and psoriasis (Ps) overlaps, particularly the activation of the immune response and tissue damage. Here, we evaluated galectin (Gal)-1 and Gal-3 levels, which are beta-galactoside-binding proteins with immunomodulatory functions and examined their effects on human keratinocytes stimulated with either interleukin (IL)-4 or IL-17A. Skin biopsies from AD, Ps, and control patients were evaluated using histological and immunohistochemical analyses. Six studies containing publicly available transcriptome data were individually analyzed using the GEO2R tool to detect Gal-1 and Gal-3 mRNA levels. In vitro, IL-4- or IL-17A-stimulated keratinocytes were treated with or without Gal-1 or Gal-3 to evaluate cytokine release and migration. Our findings showed different patterns of expression for Gal-1 and Gal-3 in AD and Ps skins. Densitometric analysis in skin samples showed a marked increase in the protein Gal-1 levels in Ps epidermis and in both AD and Ps dermis compared to controls. Protein and mRNA Gal-3 levels were downregulated in AD and Ps lesional skin compared with the control samples. In vitro, both galectins addition abrogated the release of IL-8 and RANTES in IL-17-stimulated keratinocytes after 24 h, whereas IL-6 release was downregulated by Gal-3 and Gal-1 in IL-4- and IL-17-stimulated cells, respectively. Administration of both galectins also increased the rate of keratinocyte migration under IL-4 or IL-17 stimulation conditions compared with untreated cells. Altogether, the immunoregulatory and migration effects of Gal-1 and Gal-3 on keratinocytes under inflammatory microenvironment make them interesting targets for future therapies in cutaneous diseases.

Enhanced Susceptibility of Galectin-1 Deficient Mice to Experimental Colitis

Galectin-1 is a β-galactoside-binding lectin, ubiquitously expressed in stromal, epithelial, and different subsets of immune cells. Galectin-1 is the prototype member of the galectin family which shares specificity with β-galactoside containing proteins and lipids. Immunomodulatory functions have been ascribed to endogenous galectin-1 due to its induction of T cell apoptosis, inhibitory effects of neutrophils and T cell trafficking. Several studies have demonstrated that administration of recombinant galectin-1 suppressed experimental colitis by modulating adaptive immune responses altering the fate and phenotype of T cells. However, the role of endogenous galectin-1 in intestinal inflammation is poorly defined. In the present study, the well-characterized acute dextran sulfate sodium (DSS)-induced model of ulcerative colitis was used to study the function of endogenous galectin-1 during the development of intestinal inflammation. We found that galectin-1 deficient mice (Lgals1-/- mice) displayed a more severe intestinal inflammation, characterized by significantly elevated clinical scores, than their wild type counterparts. The mechanisms underlying the enhanced inflammatory response in colitic Lgals1-/- mice involved an altered Th17/Th1 profile of effector CD4+ T cells. Furthermore, increased frequencies of Foxp3+CD4+ regulatory T cells in colon lamina propria in Lgals1-/- mice were found. Strikingly, the exacerbated intestinal inflammatory response observed in Lgals1-/- mice was alleviated by adoptive transfer of wild type Foxp3+CD4+ regulatory T cells at induction of colitis. Altogether, these data highlight the importance of endogenous galectin-1 as a novel determinant in regulating T cell reactivity during the development of intestinal inflammation.

The Role of Galectin-9 as Mediator of Atopic Dermatitis: Effect on Keratinocytes

Galectin-9 (Gal-9) is a beta-galactoside-binding protein with a variety of biological functions related to immune response. However, in allergic diseases, its mechanism of action is not fully understood. This study evaluates the expression pattern of Gal-9 in patients with atopic dermatitis (AD), in ovalbumin (OVA)-induced experimental atopic dermatitis (AD) in mice, as well as its effect on human keratinocytes. The skin of OVA-immunized BALB/c mice was challenged with drops containing OVA on days 11, 14-18, and 21-24. HaCaT cells were cultured in the following experimental conditions: control (growth medium only) or stimulated with TNF-α/IFN-γ, or IL-4, or IL-17 with or without Gal-9 treatment. AD was characterized by increased levels of Gal-9 in mouse and human skin, especially in the epidermis, and with a marked influx of Gal-9 positive eosinophils and mast cells compared to the control group. Gal-9 showed an immunomodulatory effect on keratinocytes by decreasing the release of IL-6 by IL-4-stimulated keratinocytes or increasing the IL-6 and RANTES levels by IL-17- or TNF-α/IFN-γ-stimulated cells, respectively. Under IL-17, Gal-9 treatment also altered the proliferation rate of cells. Overall, increased levels of Gal-9 in AD skin contribute to the control of inflammatory response and the proliferative process of keratinocytes, suggesting this lectin as a relevant therapeutic target.

Galectin-1 Inhibited LPS-Induced Autophagy and Apoptosis of Human Periodontal Ligament Stem Cells

Periodontitis is a widespread human chronic inflammatory disease of the tooth-surrounding tissues, which induces the destruction of periodontium and pathologic loss of teeth among adults. It has been reported that interleukin (IL)-17 was significantly increased in periodontitis patients compared to controls, while galectin-1 (Gal-1) was lower. Interestingly, it is found that Gal-1 treatment reduced systemic IL-17 levels. Hence, the aim of the present study was to explore the effect of Gal-1 on periodontitis development and investigate its underlying mechanism. In this study, Gal-1 was poorly expressed in lipopolysaccharide (LPS)-induced human periodontal ligament stem cells (hPDLSCs), and Gal-1 overexpression attenuated the production of inflammatory cytokines induced by LPS. Moreover, Gal-1 overexpression alleviated LPS-induced cell autophagy and apoptosis and reduced the expressions of IL-17A and IL-17R. Interestingly, IL-17A reversed the effect of Gal-1 on cell autophagy, inflammation, and cell apoptosis induced by the LPS challenge. In conclusion, Gal-1 inhibited LPS-induced autophagy and apoptosis of hPDLSC via regulation of IL-17A expression. Therefore, Gal-1 may have promising potential in regenerating periodontium.

Galectin-1 Expression in CD8+ T Lymphocytes Controls Inflammation in Contact Hypersensitivity

Allergic contact dermatitis, also known as contact hypersensitivity, is a frequent T-cell‒mediated inflammatory skin disease characterized by red, itchy, swollen, and cracked skin. It is caused by the direct contact with an allergen and/or irritant hapten. Galectin-1 (Gal-1) is a β-galactoside‒binding lectin, which is highly expressed in several types of immune cells. The role of endogenous Gal-1 in contact hypersensitivity is not known. We found that Gal-1‒deficient mice display more sustained and prolonged skin inflammation than wild-type mice after oxazolone treatment. Gal-1‒deficient mice have increased CD8⁺ T cells and neutrophilic infiltration in the skin. After the sensitization phase, Gal-1‒depleted mice showed an increased frequency of central memory CD8⁺ T cells and IFN-γ secretion by CD8⁺ T cells. The absence of Gal-1 does not affect the migration of transferred CD4⁺ and CD8⁺ T cells from the blood to the lymph nodes or to the skin. The depletion of CD4⁺ T lymphocytes as well as adoptive transfer experiments demonstrated that endogenous expression of Gal-1 on CD8⁺ T lymphocytes exerts a major role in the control of contact hypersensitivity model. These data underscore the protective role of endogenous Gal-1 in CD8⁺ but not CD4⁺ T cells in the development of allergic contact dermatitis.

Assessment of saliva and gingival crevicular fluid soluble urokinase plasminogen activator receptor (suPAR), galectin-1, and TNF-α levels in periodontal health and disease

OBJECTIVE

The aim of the study is to evaluate saliva and gingival crevicular fluid (GCF) levels of suPAR and galectin-1 in different periodontal health status and relationship between these molecules and TNF-α to understand the roles of these molecules in periodontal inflammation process.

BACKGROUND

Soluble urokinase plasminogen activator receptor (suPAR) has been described as a biological marker of inflammation and immunological activation. Galectin-1, a member of the galectin family, is an anti-inflammatory cytokine. However, to date, levels of these two molecules in periodontal health and disease have not been well documented.

METHODS

A total of 60 individuals, 20 with chronic periodontitis (group P), 20 with gingivitis (group G), and 20 with healthy periodontium (group H) were recruited for this study. Full-mouth clinical periodontal measurements were recorded in periodontal charts. GCF and whole saliva samples were collected to determine the levels of suPAR, galectin-1, and TNF-α in study groups using enzymelinked immunosorbent assay (ELISA) method.

RESULTS

The GCF total amount of suPAR, galectin-1, and TNF-α in GCF was similar in group P and G (P > .05). The GCF total amounts of these molecules in GCF were higher in the group G and P compared to the group H (P < .05), whereas the GCF concentrations of suPAR and galectin-1 were lower in the group G and P compared to the group H (P < .05).The saliva concentration of suPAR was significantly higher in group P compared to the group G and H (P < .05). It was also higher in the group G compared to the group H but there is no significant difference between the groups (P > .05). Salivary galectin-1 levels were similar in the study groups (P > .05).

CONCLUSION

Increased levels of GCF suPAR, galectin-1, and saliva suPAR in periodontal disease suggest that these molecules may play a role in the periodontal inflammation. suPAR and galectin-1 may be considered as potential biomarkers in periodontal disease.

Galectin-1 ameliorates lipopolysaccharide-induced acute lung injury via AMPK-Nrf2 pathway in mice

Inflammation and oxidative stress contribute to the progression of acute lung injury (ALI). Galectin-1 (Gal-1) has important anti-inflammatory properties in renal ischemia-reperfusion injury, arthritis, uveitis, and hepatitis. However, whether Gal-1 could protect against ALI is still poorly elucidated. The current study aimed to investigate the protective effects of Gal-1 against lipopolysaccharide (LPS)-induced ALI and the underlying mechanisms. Accordingly, we found that pretreatment with Gal-1 attenuated the lung tissue injury induced by LPS, with the recovery of lung function, protecting against the production of pro-inflammatory cytokines and oxidative stress. We also confirmed the therapeutic potential of Gal-1 on the survival rate of LPS-challenged mice. In vitro studies demonstrated the protective effects of exogenous Gal-1 through downregulating pro-inflammatory cytokines release and oxidative stress in primary macrophages challenged by LPS. In addition, Gal-1 suppressed TXNIP-NLRP3 inflammasome activation in ALI mice and LPS-treated primary macrophages partly through directly binding to the NLRP3 protein. Gal-1 alleviated LPS-induced lung injury via activation of Nrf-2, which may be associated with AMPK phosphorylation. Collectively, our experimental results firstly provided the support that Gal-1 effectively protected against LPS-induced ALI via suppression of inflammation response and oxidative stress, which were largely dependent on the upregulation of the Nrf2 pathway via phosphorylation of AMPK. These results suggest that Gal-1 could be a valuable therapeutic candidate in the treatment of ALI.

Anti-inflammatory Property of Galectin-1 in a Murine Model of Allergic Airway Inflammation

Galectin-1 (Gal-1) has immunomodulatory activities in various allergic inflammatory disorders, but its potential anti-inflammatory properties on allergic airway diseases have not been confirmed. We explored the pharmacological effects of Gal-1 on the progression of allergic airway inflammation and investigated the underlying mechanism. Female C57BL/6 mice were sensitized on day 0 and challenged with ovalbumin (OVA) on days 14-17 to establish an allergic airway inflammation model. In the challenge phase, a subset of mice was treated intraperitoneally with recombinant Gal-1 (rGal-1) or dexamethasone (Dex). We found that rGal-1 inhibited pulmonary inflammatory cell recruitment, mucus secretion, bronchoalveolar lavage fluid (BALF) inflammatory cell infiltration, and cytokine production. The treatment also suppressed the infiltration of eosinophils into the allergic lung as indicated by decreased expression levels of eotaxin and eosinophil peroxidase (EPX). However, only the expression levels of IL-25, neither IL-33 nor TSLP, were significantly decreased in the lung by rGal-1 treatment. These immunomodulatory effects in the allergic lung were correlated with the activation of extracellular signal-regulated kinase (ERK) signaling pathway and downregulation of endogenous Gal-1. In addition, rGal-1 reduced the plasma concentrations of anti-OVA immunoglobulin E (IgE) and IL-17. Our findings suggest that rGal-1 is an effective therapy for allergic airway inflammation in a murine model and may be a potential pharmacological target for allergic airway inflammatory diseases.

Lack of Endogenous Annexin A1 Increases Mast Cell Activation and Exacerbates Experimental Atopic Dermatitis

Annexin A1 (AnxA1) is a protein with potent anti-inflammatory actions and an interesting target that has been poorly explored in skin inflammation. This work evaluated the lack of endogenous AnxA1 in the progression of ovalbumin (OVA)-induced atopic dermatitis (AD)-like skin lesions. OVA/Alum-immunized C57BL/6 male wild-type (WT) and AnxA1 null (AnxA1-/-) mice were challenged with drops containing OVA on days 11, 14⁻18 and 21⁻24. The AnxA1-/- AD group exhibited skin with intense erythema, erosion and dryness associated with increased skin thickness compared to the AD WT group. The lack of endogenous AnxA1 also increased IgE relative to WT animals, demonstrating exacerbation of the allergic response. Histological analysis revealed intense eosinophilia and mast-cell activation in AD animals, especially in AnxA1-/-. Both AD groups increased skin interleukin (IL)-13 levels, while IL-17A was upregulated in AnxA1-/- lymph nodes and mast cells. High levels of phosphorylated ERK were detected in keratinocytes from AD groups. However, phospho-ERK levels were higher in the AnxA1-/- when compared to the respective control groups. Our results suggest AnxA1 as an important therapeutic target for inflammatory skin diseases.