Imiquimod Mouse Research Articles

Posidonia oceanica (L.) Delile Is a Promising Marine Source Able to Alleviate Imiquimod-Induced Psoriatic Skin Inflammation.

Psoriasis is a chronic immune-mediated inflammatory cutaneous disease characterized by elevated levels of inflammatory cytokines and adipokine Lipocalin-2 (LCN-2). Recently, natural plant-based products have been studied as new antipsoriatic compounds. We investigate the ability of a leaf extract of the marine plant Posidonia oceanica (POE) to inhibit psoriatic dermatitis in C57BL/6 mice treated with Imiquimod (IMQ). One group of mice was topically treated with IMQ (IMQ mice) for 5 days, and a second group received POE orally before each topical IMQ treatment (IMQ-POE mice). Psoriasis Area Severity Index (PASI) score, thickness, and temperature of the skin area treated with IMQ were measured in both groups. Upon sacrifice, the organs were weighed, and skin biopsies and blood samples were collected. Plasma and lesional skin protein expression of IL-17, IL-23, IFN-γ, IL-2, and TNF-α and plasma LCN-2 concentration were evaluated by ELISA. PASI score, thickness, and temperature of lesional skin were reduced in IMQ-POE mice, as were histological features of psoriatic dermatitis and expression of inflammatory cytokines and LCN-2 levels. This preliminary study aims to propose P. oceanica as a promising naturopathic anti-inflammatory treatment that could be introduced in Complementary Medicine for psoriasis.

Livin expression promotes keratinocyte release of inflammatory mediators in psoriasis.

Psoriasis is a prevalent, long-term skin condition characterized by inflammation. Keratinocytes (KCs) are important effector cells that release inflammatory factors and chemokines to promote the inflammatory cascade in psoriasis. However, the mechanisms underlying the activation of KCs in psoriasis remain unclear. Livin suppresses apoptotic proteins and directly affects the growth and spread of cancer cells. Livin expression reportedly increases significantly in lesions of patients with psoriasis; however, its specific role in KC activation remains unknown. This study aimed to examine the impact of Livin on KC activation and the subsequent release of inflammatory mediators. Immunofluorescence staining, reverse transcription-quantitative polymerase chain reaction, enzyme-linked immunosorbent assay (ELISA), and western blotting were used to assess Livin expression in patients with psoriasis, an imiquimod (IMQ)-induced psoriasis-like mouse model, and M5-treated HaCaT cells. To investigate the role of Livin in KCs, we performed RNA sequencing and proteomic analysis of Livin-knockdown (knockdown-HaCaT) and negative control (NC-HaCaT) cells. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes were used for enrichment analyses. Moreover, the effect of Livin expression on the release of inflammatory mediators in KCs was verified using ELISA. Livin expression was higher in KCs of patients with psoriasis than in those healthy controls. Livin expression in HaCaT cells treated with M5 increased significantly over time. Livin expression was higher in the skin lesions of the IMQ mouse model than in the control group. Proteomic analysis and RNA sequencing used to investigate the function of Livin in HaCaT cells revealed its potential role in mediating KC activation and inflammatory mediator release, which affected the pathology of psoriasis. Livin expression played an effect on KCs activation, which induced release of inflammatory mediators and up-regulation of keratin. This study provides a new effector molecule for the mechanism of inflammatory response in psoriasis.

Aberrant promoter methylation of Wnt inhibitory factor-1 gene is a potential target for treating psoriasis

Psoriasis is a chronic inflammatory skin disease mediated by immune and complex genetic factors. The wingless-related integration site (Wnt) signaling pathway plays a critical role in psoriasis, but how the Wnt pathway is regulated in psoriatic skin and whether it can be exploited for therapeutic benefits is unclear. By comparing biopsies from healthy and psoriatic skin, we found that Wnt inhibitory factor 1 (WIF1), an inhibitor of Wnt signaling, showed reduced expression at both mRNA and protein levels in psoriatic skin. We then quantified methylation of the WIF1 gene promoter by DNA methylation sequencing and found that the WIF1 promoter region was hypermethylated. We further showed that recombinant WIF1 injection ameliorates the imiquimod (IMQ) mouse model of psoriasis. We also revealed that treatment with the DNA methylation inhibitor, decitabine, inhibited proliferation of immortalized human keratinocytes (HaCaT) in a psoriasis-like inflammatory environment. Finally, we applied decitabine to the IMQ mouse model and demonstrated that treatment of mice with decitabine ameliorates the disease. Therefore, our study reveals that methylation of the WIF1 gene is associated with the pathogenesis of psoriasis, and suggests that pharmacological targeting of DNA methylation is a potential treatment strategy for psoriasis.

Lenalidomide attenuates IMQ-induced inflammation in a mouse model of psoriasis

Psoriasis is a type of chronic autoimmune-mediated inflammatory skin condition in which clinical manifestations are characterized by erythema and scaly changes, with complex pathogenesis and ease of relapse, and it is difficult to cure. Lenalidomide (Len) is a structural analog of thalidomide, which belongs to the second generation of immunomodulators and has the functions of tumor killing, immune regulation, anti-angiogenesis and regulation of the myeloma microenvironment. In the current experiment, we investigated the therapeutic effect of transdermal application of Len on the pathological changes of imiquimod (IMQ)-induced skin irritations and inflammation in psoriatic-like mice. The in vivo results revealed that Len nanoemulsion-based gels markedly reduced the IMQ-induced Psoriasis Area Severity Index (PASI) score, spleen-to-body weight index and CD4 protein expression in the derma of mice and improved IMQ-induced skin inflammatory cell infiltration. Transcriptome sequencing was intended to obtain the differentially expressed genes among the skin of Con mice and the skin of IMQ mice, and then, the GO enrichment classification and KEGG pathway analysis of the significant genes was executed to obtain major signaling pathways in the pathogenesis of the psoriasis mouse model. It was found that the PI3K/AKT signaling pathway was a major pathway in the pathogenesis of psoriasis in a mouse model induced by IMQ. The immunohistochemical results confirmed that Len could modulate the protein expression of AKT and NF-κB in skin. In conclusion, the protective effect of transdermal administration of Len may be related to the inhibition of the PI3K/AKT signaling pathway and its downstream NF-κB pathway against IMQ-induced psoriasis in mice.

Trimethylamine N-Oxide Promotes Autoimmunity and a Loss of Vascular Function in Toll-like Receptor 7-Driven Lupus Mice.

Plasma levels of trimethylamine N-oxide (TMAO) are elevated in lupus patients. We analyzed the implication of TMAO in autoimmunity and vascular dysfunction of the murine model of systemic lupus erythematosus (SLE) induced by the activation of the Toll-like receptor (TLR)7 with imiquimod (IMQ). Female BALB/c mice were randomly divided into four groups: untreated control mice, control mice treated with the trimethylamine lyase inhibitor 3,3-dimethyl-1-butanol (DMB), IMQ mice, and IMQ mice treated with DMB. The DMB-treated groups were administered the substance in their drinking water for 8 weeks. Treatment with DMB reduced plasma levels of TMAO in mice with IMQ-induced lupus. DMB prevents the development of hypertension, reduces disease progression (plasma levels of anti-dsDNA autoantibodies, splenomegaly, and proteinuria), reduces polarization of T lymphocytes towards Th17/Th1 in secondary lymph organs, and improves endothelial function in mice with IMQ-induced lupus. The deleterious vascular effects caused by TMAO appear to be associated with an increase in vascular oxidative stress generated by increased NADPH oxidase activity, derived in part from the vascular infiltration of Th17/Th1 lymphocytes, and reduced nrf2-driven antioxidant defense. In conclusion, our findings identified the bacterial-derived TMAO as a regulator of immune system, allowing for the development of autoimmunity and endothelial dysfunction in SLE mice.

High salt diet impairs dermal tissue remodeling in a mouse model of IMQ induced dermatitis.

Recent animal studies, as well as quantitative sodium MRI observations on humans demonstrated that remarkable amounts of sodium can be stored in the skin. It is also known that excess sodium in the tissues leads to inflammation in various organs, but its role in dermal pathophysiology has not been elucidated. Therefore, our aim was to study the effect of dietary salt loading on inflammatory process and related extracellular matrix (ECM) remodeling in the skin. To investigate the effect of high salt consumption on inflammation and ECM production in the skin mice were kept on normal (NSD) or high salt (HSD) diet and then dermatitis was induced with imiquimod (IMQ) treatment. The effect of high salt concentration on dermal fibroblasts (DF) and peripheral blood mononuclear cells (PBMC) was also investigated in vitro. The HSD resulted in increased sodium content in the skin of mice. Inflammatory cytokine Il17 expression was elevated in the skin of HSD mice. Expression of anti-inflammatory Il10 and Il13 decreased in the skin of HSD or HSD IMQ mice. The fibroblast marker Acta2 and ECM component Fn and Col1a1 decreased in HSD IMQ mice. Expression of ECM remodeling related Pdgfb and activation phosphorylated (p)-SMAD2/3 was lower in HSD IMQ mice. In PBMCs, production of IL10, IL13 and PDGFB was reduced due to high salt loading. In cultured DFs high salt concentration resulted in decreased cell motility and ECM production, as well. Our results demonstrate that high dietary salt intake is associated with increased dermal pro-inflammatory status. Interestingly, although inflammation induces the synthesis of ECM in most organs, the expression of ECM decreased in the inflamed skin of mice on high salt diet. Our data suggest that salt intake may alter the process of skin remodeling.

Gut Microbiota Has a Crucial Role in the Development of Hypertension and Vascular Dysfunction in Toll-like Receptor 7-Driven Lupus Autoimmunity.

Our group has investigated the involvement of gut microbiota in hypertension in a murine model of systemic lupus erythematosus induced by Toll-like receptor (TLR)-7 activation. Female BALB/c mice were randomly assigned to four experimental groups: an untreated control (CTR), a group treated with the TLR7 agonist imiquimod (IMQ), IMQ-treated with vancomycin, and IMQ-treated with a cocktail of broad-spectrum antibiotics. We carried out faecal microbiota transplant (FMT) from donor CTR or IMQ mice to recipient IMQ or CTR animals, respectively. Vancomycin inhibited the increase in blood pressure; improved kidney injury, endothelial function, and oxidative stress; and reduced T helper (Th)17 infiltration in aortas from IMQ-treated mice. The rise in blood pressure and vascular complications present in IMQ mice were also observed in the CTR mice recipients of IMQ microbiota. Reduced relative populations of Sutterella and Anaerovibrio were associated with high blood pressure in our animals, which were increased after stool transplantation of healthy microbiota to IMQ mice. The reduced endothelium-dependent vasodilator responses to acetylcholine induced by IMQ microbiota were normalized after interleukin-17 neutralization. In conclusion, gut microbiota plays a role in the TLR7-driven increase in Th17 cell, endothelial dysfunction, vascular inflammation, and hypertension. The vascular changes induced by IMQ microbiota were initiated by Th17 infiltrating the vasculature.

Probiotics Prevent Hypertension in a Murine Model of Systemic Lupus Erythematosus Induced by Toll-Like Receptor 7 Activation.

Our group tested the effects of Lactobacillus fermentum CECT5716 (LC40) and/or Bifidobacterium breve CECT7263 (BFM) in the prevention of gut dysbiosis, hypertension and endothelial dysfunction in a pharmacologically-induced model of systemic lupus erythematosus (SLE). We treated eight-week-old BALB/cByJRj mice without (Ctrl) or with the agonist of TLR-7 Imiquimod (IMQ) for 8 weeks. Concomitantly, LC40 (109 CFU/mL) and BFM (109 CFU/mL) were administered through oral gavage once a day. IMQ induced intestinal dysbiosis consisting of a decrease in the α-diversity measured with Chao-richness and numbers of species. LC40 and BFM did not restore these parameters. The three-dimensional principal component analysis of bacterial taxa in stool samples presented perfect clustering between Ctrl and IMQ groups. Clusters corresponding to LC40 and BFM were more akin to IMQ. BFM and LC40 were detected colonizing the gut microbiota of mice treated respectively. LC40 and BFM decreased plasma double-stranded DNA autoantibodies, and B cells in spleen, which were increased in the IMQ group. Also, LC40 and BFM treatments activated TLR9, reduced T cells activation, and Th17 polarization in mesenteric lymph nodes. Aortae from IMQ mice displayed a decreased endothelium-dependent vasodilator response to acetylcholine linked to pro-inflammatory and pro-oxidative status, which were normalized by both BFM and LC40. In conclusion, we demonstrate for the first time that the chronic treatment with LC40 or BFM prevented hypertension and endothelial dysfunction in a mouse lupus model induced by TLR-7 activation.

Thymol activates TRPM8-mediated Ca2+ influx for its antipruritic effects and alleviates inflammatory response in Imiquimod-induced mice

Psoriasis is a highly prevalent chronic dermatitis, characterized by widespread skin inflammation and spontaneous itch. Given the adverse reactions and drug dependence of current treatment, new drugs for psoriasis therapy are urgently needed. This study aims to explore the anti-psoriatic effects of thymol in imiquimod (IMQ) induced mice, and elucidate the potential mechanisms for its therapeutic activities. Thymol reduced the scratching behavior in IMQ mice, and activated Ca2+ response in cervical DRG neurons via TRPM8 channel. Also, thymol alleviated psoriasis-like skin lesions, and attenuated the enhanced infiltration of dermal neutrophils, dendritic cells (DCs) and Th17 cells. In addition, it reversed the upregulated expression of pro-inflammatory cytokines in the skin (TNF-α, IL-22, IL-23, IL-17A, IL-17F, IL-17C, IL-6, IL-1β and IFN-γ) and serum (TNF-α, IL-6, IL-1β, IL-17A and IFN-γ). Our results indicated that thymol can effectively ameliorate pruritus and the symptoms of psoriasis-like inflammation induced by IMQ, which makes it a promising drug for the treatment of psoriasis.

Psoriatic skin inflammation induces a pre-diabetic phenotype via the endocrine actions of skin secretome

ObjectivePsoriasis is a chronic inflammatory skin disease that is thought to affect ∼2% of the global population. Psoriasis has been associated with ∼30% increased risk of developing type 2 diabetes (T2D), with numerous studies reporting that psoriasis is an independent risk-factor for T2D, separate from underlying obesity. Separately, studies of skin-specific transgenic mice have reported altered whole-body glucose homeostasis in these models. These studies imply a direct role for skin inflammation and dysfunction in mediating the onset of T2D in psoriasis patients, potentially via the endocrine effects of the skin secretome on key metabolic tissues. We used a combination of in vivo and ex vivo mouse models and ex vivo human imiquimod (IMQ) models to investigate the effects of psoriasis-mediated changes in the skin secretome on whole-body metabolic function. MethodsTo induce psoriatic skin inflammation, mice were topically administered 75 mg of 5% IMQ cream (or Vaseline control) to a shaved dorsal region for 4 consecutive days. On day 5, mice were fasted for glucose and insulin tolerance testing, or sacrificed in the fed state with blood and tissues collected for analysis. To determine effects of the skin secretome, mouse skin was collected at day 5 from IMQ mice and cultured for 24 h. Conditioned media (CM) was collected and used 1:1 with fresh media to treat mouse explant subcutaneous adipose tissue (sAT) and isolated pancreatic islets. For human CM experiments, human skin was exposed to 5% IMQ cream for 20 min, ex vivo, to induce a psoriatic phenotype, then cultured for 24 h. CM was collected, combined 1:1 with fresh media and used to treat human sAT ex vivo. Markers of tissue inflammation and metabolic function were determined by qPCR. Beta cell function in isolated islets was measured by dynamic insulin secretion. Beta-cell proliferation was determined by measurement of Ki67 immunofluorescence histochemistry and BrDU uptake, whilst islet apoptosis was assessed by caspase 3/7 activity. All data is expressed as mean ± SEM. ResultsTopical treatment with IMQ induced a psoriatic-like phenotype in mouse skin, evidenced by thickening, erythema and inflammation of the skin. Topical IMQ treatment induced inflammation and signs of metabolic dysfunction in sub-cutaneous and epidydimal adipose tissue, liver, skeletal muscle and gut tissue. However, consistent with islet compensation and a pre-diabetic phenotype, IMQ mice displayed improved glucose tolerance, increased insulin and c-peptide response to glucose, and increased beta cell proliferation. Treatment of sAT with psoriatic mouse or human skin-CM replicated the in vivo phenotype, leading to increased inflammation and metabolic dysfunction in mouse and human sAT. Treatment of pancreatic islets with psoriatic mouse skin-CM induced increases in beta-proliferation and apoptosis, thus partially replicating the in vivo phenotype. ConclusionsPsoriasis-like skin inflammation induces a pre-diabetic phenotype, characterised by tissue inflammation and markers of metabolic dysfunction, together with islet compensation in mice. The in vivo phenotype is partially replicated by exposure of sAT and pancreatic islets to psoriatic-skin conditioned media. These results support the hypothesis that psoriatic skin inflammation, potentially via the endocrine actions of the skin secretome, may constitute a novel pathophysiological pathway mediating the development of T2D.

065 CDK7 inhibitor suppresses psoriasis inflammation via inhibiting glycolysis to modulate Th17/Treg balance

Psoriasis is a chronic inflammatory disease characterized by hyper-activated Th17 and suppressive Treg cells, but the mechanism of Th17/Treg cells imbalance is still unclear. Cyclin-dependent kinase 7(CDK7) which is known as a cell cycle regulator has been reported an anti-inflammatory effect in immuno-cells. Here we firstly found CD4+T cells of psoriasis patients expressed higher levels of CDK7 along with an increased glycolysis levels than those in healthy controls. The chemical inhibitor of CDK7 called THZ1 restricted glycolytic metabolism in CD4+T cells of psoriasis patients as well as typical glycolysis related genes. More importantly, THZ1 could suppress Th17 cell differentiation and promote Treg cell differentiation even under Th17 polarizing condition in vitro. Intraperitoneal injection of THZ1 in mice exhibited an alleviated epidermal hyperplasia and alleviated inflammation caused by imiquimod(IMQ) treatment. THZ1-treated IMQ mice had significantly lower ratio of Th17 cells and higher ratio of Treg cells from the splenocytes, in comparison with vehicle-treated IMQ mice. Furthermore, we identified IL-23 as an upstream regulator that stimulated CDK7 expression and glycolysis through p-AKT-Hif-1α signalling pathway. Taken together, our results showed that abnormal CDK7 expression induced by IL-23 in CD4+ T cells in psoriasis patients contributed to the enhanced glycolysis levels which lead to the imbalance of Th17/Treg cells. CDK7 inhibitor THZ1 may serve as an immuno-modulator for psoriasis therapy in the future.

Mechanism of danshensu-induced inhibition of abnormal epidermal proliferation in psoriasis

Psoriasis is a chronic, inflammatory skin disease with high incidence and high rates of relapse, for which no satisfactory treatments are currently available. Yes-associated protein (YAP) is highly expressed in psoriasis and may regulate the proliferation and apoptosis of keratinocytes. Danshen is a traditional Chinese medicine, commonly used in the treatment of psoriasis. Danshensu is the most abundant water-soluble component of Danshen, but its therapeutic mechanism is still unclear. In this study, MTT was used to detect the effects of different danshensu concentrations (0.125, 0.25, 0.5 mmol/l) on the proliferation of an M5-based psoriasis cell model. The effects of danshensu on cell cycle and apoptosis were detected by flow cytometry. Cyclins and apoptosis-related proteins were evaluated by Western blot. Danshensu (20, 40, 80 mg/kg/day) was administered intraperitoneally to the imiquimod (IMQ) psoriasis mouse model. After 7 days, the expression of YAP in the lesions was detected by immunohistochemistry and Western blot. We found that danshensu reduced the expression of YAP in the M5 psoriasis cell model, inhibited cell proliferation, induced cell cycle arrest in G0/G1 phase, and promoted cell apoptosis. All these effects were partly reverted by YAP overexpression. The skin lesions of IMQ mice were thinned and the scales reduced after intragastric administration of danshensu, which also resulted in dose-dependent inhibition of YAP expression. We concluded that danshensu prevents abnormal epidermis proliferation in psoriasis possibly by modulating YAP expression. Our work can provide a theoretical basis for the clinical application of Danshen in the treatment of psoriasis.

014 Psoriatic regulatory T cells are impaired in their suppressive activity and respond differently to IL-33

Interleukin 33 (IL-33), initially described as an alarmin released by cells following cell damage, can also act immunosuppressive by inducing regulatory T cells (Treg). Disruption of the skin barrier by tape stripping in mice released IL-33 which induced Treg. Accordingly, contact hypersensitivity (CHS) was suppressed upon barrier disruption. Furthermore, blockade of IL-33 enhanced CHS, whereas injection of IL-33 suppressed CHS via induction of Treg. IL-33 is enhanced in the skin and serum of psoriatic patients. On the other hand, in psoriasis Treg are impaired in their suppressive activity. Thus, we asked whether “psoriatic” Treg are impaired in their response to IL-33 in the imiquimod (IMQ)-induced psoriasis like model. IL-33 was enhanced in skin and serum of IMQ-mice. To study the influence of IL-33 on Treg in IMQ-mice, CD4+CD25+ Treg isolated from IMQ or untreated mice were injected into naïve mice which were sensitized 24 h later. Ear challenge was reduced in mice receiving Treg from untreated donors, whereas injection of Treg from IMQ-mice did not cause suppression, implying impairment of Treg in IMQ-mice. To study the response of Treg to IL-33 in IMQ-mice, Treg from untreated or IMQ-mice were incubated with IL-33 and injected into naïve mice which were sensitized thereafter. The suppressive capacity of Treg from WT mice was further enhanced by IL-33, whereas Treg from IMQ mice did not to respond to IL-33. Treg isolated from blood of psoriatic patients were inhibited in their suppressive activity, when compared to Treg from healthy controls. IL-33 induced the expression of Foxp3 in CD4+ T cells obtained from controls, but not in T cells from psoriatic patients. These data confirm that in psoriasis Treg are functionally impaired which may be associated with an altered response to IL-33. The mechanisms responsible for this altered behavior of Treg in psoriasis remain to be elucidated.

Genistein suppresses psoriasis-related inflammation through a STAT3–NF-κB-dependent mechanism in keratinocytes

Psoriasis is a chronic recurrent skin inflammatory disease, and inhibition of inflammation may be an effective means of treating psoriasis. The flavonoid genistein has a clear anti-inflammatory effect. However, the anti-psoriatic effects of genistein and their underlying mechanisms remain unclear. In this study, we investigated the effects of genistein on imiquimod (IMQ)-induced psoriasis-like skin lesions in vivo and explored the mechanisms underlying those effects in vitro. It was found that genistein can significantly improve IMQ-induced pathological scores of cutaneous skin lesions in mice, reduce epidermal thickness, and inhibit the expression of inflammatory factors，including interleukin (IL)-1β, IL-6, tumour necrosis factor-alpha (TNF-α), chemokine ligand 2 (CCL2), IL-17 and IL-23. In vitro studies, genistein inhibited the proliferation of human keratinocyte HaCaT cells and inhibited the expression of inflammatory factors in a dose-dependent manner which induced by TNFα. Further researches showed that genistein could also significantly inhibit phosphorylated STAT3 (pSAT3) expression in IMQ mice dorsal skin and in TNF-α-induced HaCaT cells. The inhibitory effect of genistein on the expression of IL-6, IL-23 and TNF-α was weakened after Stat3 siRNA in HaCaT cells. Genistein could also significantly inhibit TNF-α induced the nuclear translocation of NF-κB, and inhibit the phosphorylation of I-kBα (pI-kBα). After combining with NF-κB blocker BAY 11–7082, the effect of genistein down-regulate the expression of TNF-α and VEGFA was attenuated in HaCaT cells. The results suggest that genistein may be developed for the treatment of psoriasis lesions.

Hesperidin inhibits keratinocyte proliferation and imiquimod-induced psoriasis-like dermatitis via the IRS-1/ERK1/2 pathway

AimsTo evaluate the therapeutic benefits of Hesperidin (Hes) using an imiquimod (IMQ)-induced psoriasis-like mouse model and human immortalized keratinocytes (HaCaT) cells stimulated with lipopolysaccharide (LPS). MethodsMice were treated with IMQ and orally administered Hes (125–500 mg/kg/day), methotrexate (MTX) 1 mg/kg/day or distilled water. HaCaT cells were stimulated with LPS (1 μg/mL) and relevant indices were measured after administration with different concentrations of Hes (5–20 μg/mL) for 24 h. Inflammatory skin lesions in IMQ mice were evaluated using the psoriasis area severity index (PASI) and pathological staining. Proteins in the IRS-1/ERK1/2 pathway and inflammatory factors were assessed using western blotting or quantitative real-time PCR. In addition, factors related to IRS-1 secretion levels were assessed by enzyme-linked immunosorbent assays. Extracellular flux (XF) analysis was used to assess cellular metabolic levels. Key findingsHes significantly improved psoriasis-like skin lesions of IMQ-treated mice and inhibited LPS-induced HaCaT cell proliferation. In addition, Hes remarkably decreased PASI scores, reduced epidermal thickness, decreased proliferation and differentiation of epidermal cells, inhibited mRNA expression of inflammatory factors, reduced local skin lesions and serum insulin and glucose levels. Furthermore, Hes modulated the secretion levels of serum Leptin, Adiponectin and Resistin, and inhibited the activation of the IRS-1/ERK1/2 signaling pathway and regulated HaCaT cells metabolism. SignificanceThis study demonstrated that Hes administration could have significant therapeutic value for the prevention and clinical treatment of psoriasis.

Toll-Like Receptor 7 Agonist-Induced Dermatitis Causes Severe Dextran Sulfate Sodium Colitis by Altering the Gut Microbiome and Immune Cells.

Background & AimsPsoriasis and inflammatory bowel disease (IBD) are both chronic inflammatory diseases occurring in the skin and gut, respectively. It is well established that psoriasis and IBD have high concordance rates, and similar changes in immune cells and microbiome composition have been reported in both conditions. To study this connection, we used a combination murine model of psoriatic dermatitis and colitis in which mice were treated topically with the Toll-like receptor 7 agonist imiquimod (IMQ) and fed dextran sulfate sodium (DSS).MethodsWe applied IMQ topically to B6 mice (IMQ mice) and subsequently fed them 2% DSS in their drinking water. Disease activity and immune cell phenotypes were analyzed, and the microbial composition of fecal samples was investigated using 16S ribosomal RNA sequencing. We transplanted feces from IMQ mice to germ-free IQI/Jic (IQI) mice and fed them DSS to assess the effect of the gut microbiome on disease.ResultsWe first confirmed that IMQ mice showed accelerated DSS colitis. IMQ mice had decreased numbers of IgD+ and IgM+ B cells and increased numbers of non–cytokine-producing macrophages in the gut. Moreover, the gut microbiomes of IMQ mice were perturbed, with significant reductions of Lactobacillus johnsonii and Lactobacillus reuteri populations. Germ-free mice transplanted with feces from IMQ mice, but not with feces from untreated mice, also developed exacerbated DSS colitis.ConclusionsThese results suggest that skin inflammation may contribute to pathogenic conditions in the gut via immunologic and microbiological changes. Our finding of a novel potential skin–gut interaction provides new insights into the coincidence of psoriasis and IBD.

Acetyl-11-keto-β-boswellic acid inhibits the secretion of cytokines by dendritic cells via the TLR7/8 pathway in an imiquimod-induced psoriasis mouse model and in vitro

AimsPsoriasis vulgaris is mediated by T and dendritic cells. This study aimed to investigate the effects of acetyl-11-keto-β-boswellic acid (AKBA) on activated dendritic cells (DCs) using an imiquimod (IMQ)-induced psoriasis-like mouse model and murine bone marrow–derived dendritic cells (BMDCs) stimulated with resiquimod (R848) in vitro. Materials and methodsThe mice were treated with IMQ and intragastrically administered 25–100 mg/kg/day of AKBA, 1 mg/kg/day of methotrexate (MTX), or normal saline. The inflammation of skin lesions in IMQ mice were evaluated by psoriasis area and severity index (PASI) and pathological staining. The related proteins of Toll-like receptor (TLR)7/8 pathways were assessed using Western blotting, and the expression levels of interleukin (IL)-23 and IL-12p40 mRNA using reverse transcription–polymerase chain reaction. The numbers of DCs and marker-positive BMDCs were assessed using flow cytometry and the levels of inflammatory factors using the enzyme-linked immunosorbent assay. Key findingsAKBA and MTX obviously improved the psoriasis-like skin lesions of IMQ-treated mice. AKBA also obviously decreased the PASI score, reduced the thickness of epidermis, ameliorated the infiltration of CD3+ and CD11c+ cells in skin lesions, decreased the activation of local DCs, inhibited the mRNA expression and secretion of inflammatory factors IL-12 and IL-23, inhibited the maturation and differentiation of DCs to promote T-cell differentiation, and inhibited the activation of TLR7/8 and IRF signaling pathways. SignificanceThis study implied that AKBA might have an anti-inflammatory effect on psoriasis by inhibiting the maturation and activation of DCs via the TLR8 and IRF signaling pathways.