Celastrol gel ameliorates imiquimod-induced psoriasis-like dermatitis in mice by targeting Langerhans cells

Tetrastigma hemsleyanum polysaccharides alleviate imiquimod-induced psoriasis-like skin lesions in mice by modulating the JAK/STAT3 signaling pathway

BACKGROUND

The pathogenesis of psoriasis involves the interaction between keratinocytes and immune cells, leading to immune imbalance. While most current clinical treatment regimens offer rapid symptom relief, they often come with significant side effects. Tetrastigma hemsleyanum polysaccharides (THP), which are naturally nontoxic, possess remarkable immunomodulatory and anti-inflammatory properties.

METHODS

In this study, we utilized an imiquimod (IMQ)-induced psoriasis mouse model and a LPS/IL-6-stimulated HaCaT model. The potential and mechanism of action of THP in psoriasis treatment were assessed through methods including Psoriasis Area Severity Index (PASI) scoring, histopathology, flow cytometry, immunoblotting, and reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Percutaneous administration of THP significantly alleviated symptoms and manifestations in IMQ-induced psoriatic mice, including improvements in psoriatic skin appearance (erythema, folds, scales), histopathological changes, decreased PASI scores, and spleen index. Additionally, THP suppressed abnormal proliferation of Th17 cells and excessive proliferation and inflammation of keratinocytes. Furthermore, THP exhibited the ability to regulate the JAK/STAT3 signaling pathway.

CONCLUSION

Findings from in vivo and in vitro studies suggest that THP can inhibit abnormal cell proliferation and excessive inflammation in lesional skin, balance Th17 immune cells, and disrupt the interaction between keratinocytes and Th17 cells. This mechanism of action may involve the modulation of the JAK/STAT3 signaling pathway, offering potential implications for psoriasis treatment.

Celastrol alleviates atopic dermatitis by regulating Ezrin-mediated mitochondrial fission and fusion

Celastrol, a bioactive molecule extracted from the plant Tripterygium wilfordii Hook F., possesses anti-inflammatory, anti-obesity and anti-tumour properties. Despite its efficacy in improving erythema and scaling in psoriatic mice, the specific therapeutic mechanism of celastrol in atopic dermatitis (AD) remains unknown. This study aims to examine the role and mechanism of celastrol in AD using TNF-α-stimulated HaCaT cells and DNCB-induced Balb/c mice as in vitro and in vivo AD models, respectively. Celastrol was found to inhibit the increased epidermal thickness, reduce spleen and lymph node weights, attenuate inflammatory cell infiltration and mast cell degranulation and decrease thymic stromal lymphopoietin (TSLP) as well as various inflammatory factors (IL-4, IL-13, TNF-α, IL-5, IL-31, IL-33, IgE, TSLP, IL-17, IL-23, IL-1β, CCL11 and CCL17) in AD mice. Additionally, celastrol inhibited Ezrin phosphorylation at Thr567, restored mitochondrial network structure, promoted translocation of Drp1 to the cytoplasm and reduced TNF-α-induced cellular reactive oxygen species (ROS), mitochondrial ROS (mtROS) and mitochondrial membrane potential (MMP) production. Interestingly, Mdivi-1 (a mitochondrial fission inhibitor) and Ezrin-specific siRNAs lowered inflammatory factor levels and restored mitochondrial reticular formation, as well as ROS, mtROS and MMP production. Co-immunoprecipitation revealed that Ezrin interacted with Drp1. Knocking down Ezrin reduced mitochondrial fission protein Drp1 phosphorylation and Fis1 expression while increasing the expression of fusion proteins Mfn1 and Mfn2. The regulation of mitochondrial fission and fusion by Ezrin was confirmed. Overall, celastrol may alleviate AD by regulating Ezrin-mediated mitochondrial fission and fusion, which may become a novel therapeutic reagent for alleviating AD.

Orientin alleviates the inflammatory response in psoriasis like dermatitis in BALB/c mice by inhibiting the MAPK signaling pathway

BACKGROUND

Psoriasis, a chronic inflammatory condition of the skin, is characterized by an atypical proliferation of epidermal keratinocytes and immune cell infiltration. Orientin is a flavonoid monomer with potent anti-inflammatory activities. However, the therapeutic effects of orientin on psoriasis and the underlying mechanisms have not been elucidated.

OBJECTIVE

To investigate the therapeutic effect of orientin on psoriasis and the underlying mechanisms using network pharmacology and experimental studies.

METHODS

A psoriasis-like mouse model was established using imiquimod (IMQ). Lipopolysaccharide (LPS) was used to stimulate the RAW264.7 and HaCaT cells in vitro. The therapeutic effects of orientin and the underlying mechanism were analyzed using histopathological, immunohistochemical, quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, flow cytometry, and western blotting analyses.

RESULTS

Orientin ameliorated skin lesions and suppressed keratinocyte proliferation and immune cell infiltration in the IMQ-induced psoriasis-like mouse model. Additionally, orientin inhibited the secretion of the pro-inflammatory factors interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6, IL-8, IL-17, and IL-23 in the psoriasis-like mouse model and LPS-induced RAW264.7 and HaCaT cells. Furthermore, orientin mitigated the LPS-induced upregulation of reactive oxygen species and downregulation of IL-10 and glutathione levels. Orientin alleviated inflammation by downregulating the MAPK signaling pathway.

CONCLUSION

Orientin alleviated psoriasis-like dermatitis by suppressing the MAPK signaling pathway, suggesting that orientin is a potential therapeutic for psoriasis.

Macrophage Functions in Psoriasis: Lessons from Mouse Models

Psoriasis is a systemic autoimmune/autoinflammatory disease that can be well studied in established mouse models. Skin-resident macrophages are classified into epidermal Langerhans cells and dermal macrophages and are involved in innate immunity, orchestration of adaptive immunity, and maintenance of tissue homeostasis due to their ability to constantly shift their phenotype and adapt to the current microenvironment. Consequently, both macrophage populations play dual roles in psoriasis. In some circumstances, pro-inflammatory activated macrophages and Langerhans cells trigger psoriatic inflammation, while in other cases their anti-inflammatory stimulation results in amelioration of the disease. These features make macrophages interesting candidates for modern therapeutic strategies. Owing to the significant progress in knowledge, our review article summarizes current achievements and indicates future research directions to better understand the function of macrophages in psoriasis.

Ferroptosis inhibitors reduce celastrol toxicity and preserve its insulin sensitizing effects in insulin resistant HepG2 cells

OBJECTIVE

Research has shown that celastrol can effectively treat a variety of diseases, yet when passing a certain dosage threshold, celastrol becomes toxic, causing complications such as liver and kidney damage and erythrocytopenia, among others. With this dichotomy in mind, it is extremely important to find ways to preserve celastrol's efficacy while reducing or preventing its toxicity.

METHODS

In this study, insulin-resistant HepG2 (IR-HepG2) cells were prepared using palmitic acid and used for in vitro experiments. IR-HepG2 cells were treated with celastrol alone or in combination with N-acetylcysteine (NAC) or ferrostatin-1 (Fer-1) for 12, 24 or 48 h, at a range of doses. Cell counting kit-8 assay, Western blotting, quantitative reverse transcription-polymerase chain reaction, glucose consumption assessment, and flow cytometry were performed to measure celastrol's cytotoxicity and whether the cell death was linked to ferroptosis.

RESULTS

Celastrol treatment increased lipid oxidation and decreased expression of anti-ferroptosis proteins in IR-HepG2 cells. Celastrol downregulated glutathione peroxidase 4 (GPX4) mRNA. Molecular docking models predicted that solute carrier family 7 member 11 (SLC7A11) and GPX4 were covalently bound by celastrol. Importantly, we found for the first time that the application of ferroptosis inhibitors (especially NAC) was able to reduce celastrol's toxicity while preserving its ability to improve insulin sensitivity in IR-HepG2 cells.

CONCLUSION

One potential mechanism of celastrol's cytotoxicity is the induction of ferroptosis, which can be alleviated by treatment with ferroptosis inhibitors. These findings provide a new strategy to block celastrol's toxicity while preserving its therapeutic effects. Please cite this article as: Liu JJ, Zhang X, Qi MM, Chi YB, Cai BL, Peng B, Zhang DH. Ferroptosis inhibitors reduce celastrol toxicity and preserve its insulin sensitizing effects in insulin resistant HepG2 cells. J Integr Med. 2024; 22(3): 286-294.

Inflammatory and Immunomodulatory Effects of Tripterygium wilfordii Multiglycoside in Mouse Models of Psoriasis Keratinocytes

OBJECTIVE

To determine the role of Tripterygium wilfordii multiglycoside (TGW) in the treatment of psoriatic dermatitis from a cellular immunological perspective.

METHODS

Mouse models of psoriatic dermatitis were established by imiquimod (IMQ). Twelve male BALB/c mice were assigned to IMQ or IMQ+TGW groups according to a random number table. Histopathological changes in vivo were assessed by hematoxylin and eosin staining. Ratios of immune cells and cytokines in mice, as well as PAM212 cell proliferation in vitro were assessed by flow cytometry. Pro-inflammatory cytokine expression was determined using reverse transcription quantitative polymerase chain reaction.

RESULTS

TGW significantly ameliorated the severity of IMQ-induced psoriasis-like mouse skin lesions and restrained the activation of CD45+ cells, neutrophils and T lymphocytes (all P<0.01). Moreover, TGW significantly attenuated keratinocytes (KCs) proliferation and downregulated the mRNA levels of inflammatory cytokines including interleukin (IL)-17A, IL-23, tumor necrosis factor α, and chemokine (C-X-C motif) ligand 1 (P<0.01 or P<0.05). Furthermore, it reduced the number of γ δ T17 cells in skin lesion of mice and draining lymph nodes (P<0.01).

CONCLUSIONS

TGW improved psoriasis-like inflammation by inhibiting KCs proliferation, as well as the associated immune cells and cytokine expression. It inhibited IL-17 secretion from γ δ T cells, which improved the immune-inflammatory microenvironment of psoriasis.

Celastrol regulates psoriatic inflammation and autophagy by targeting IL-17A

Anti-IL-17A antibodies, such as secukinumab and ixekizumab, are effective proinflammatory cytokine inhibitors for autoimmune disorders, including psoriasis. However, anti-IL-17A small molecule treatments are yet to be commercialized. Celastrol, a natural compound extracted from the roots of traditional Chinese medicinal plants, has anti-inflammatory and antioxidant properties. However, the binding of celastrol to IL-17A and the associated anti-inflammatory mechanisms remain unclear. This study investigated whether celastrol could directly bind to IL-17A and regulate inflammation in psoriatic in vitro and in vivo models. The results showed that celastrol directly binds to IL-17A and inhibits its downstream signaling, including the NF-kB and MAPK pathways. Interestingly, celastrol restored autophagy dysfunction and reduced proinflammatory cytokine secretion in keratinocytes. In addition, celastrol increased autophagy in the epidermis of a mouse model of psoriasis. Celastrol decreased Th17 cell populations and proinflammatory cytokine levels in mice. Thus, IL-17A-targeting celastrol reduced inflammation by rescuing impaired autophagy in in vitro and in vivo models of psoriasis, demonstrating its potential as a substitute for anti-IL-17A antibodies for treating psoriasis.

Qingxiong Ointment and its Active Ingredient, Shikonin Treat Psoriasis through HIF-1 Signaling Pathway

BACKGROUND

Psoriasis is a common chronic inflammatory skin disorder. Qingxiong ointment (QX) is a natural medicinal combination frequently employed in clinical treatment of psoriasis. However, the active ingredients of QX and its precise mechanisms of improving psoriasis remain unclear. This study elucidated the effects of QX on an Imiquimod (IMQ)-induced mouse model of psoriasis while also exploring the regulation of the active ingredient of QX, shikonin, on the HIF-1 signaling pathway in HaCaT cells.

METHODS

A mouse model of psoriasis was established through topical application of IMQ, and the local therapeutic effect of QX was evaluated using dorsal skin tissue with mouse psoriatic lesion and Psoriasis Area Severity Index (PASI) scores, hematoxylin-eosin (HE) staining, and immunohistochemical staining. Elisa and qPCR were employed to identify changes in the expression of inflammation-related factors in the mouse dorsal skin. Immunofluorescence was used to assess changes in the expression of T cell subsets before and after treatment with various doses of QX. HPLC was used to analyze the content of shikonin, and network pharmacology was employed to analyze the main targets of shikonin. Immunofluorescence was used to identify the effects of shikonin on the HIF-1 signaling pathway in IL6-induced psoriasis HaCaT cells. Finally, qPCR was used to identify the differential expression of the HIF-1 signaling pathway in skin tissues.

RESULTS

QX significantly reduces PASI scores on the backs of IMQ-induced psoriasis mice. HE staining reveals alleviated epidermal thickness in the QX group. Immunohistochemical analysis shows a significant reduction in ICAM, KI67, and IL17 expression levels in the QX group. Immunofluorescence results indicate that QX can notably decrease the proportions of CD4+ T cells, γδ T cells, and CD8+ T cells while increasing the proportion of Treg cells. Network pharmacology analysis demonstrates that the main targets of shikonin are concentrated in the HIF-1 signaling pathway. Molecular docking results show favorable binding affinity between shikonin and key genes of the HIF-1 signaling pathway. Immunofluorescence results reveal that shikonin significantly reduces p-STAT3, SLC2A1, HIF1α, and NOS2 expression levels. qPCR results show significant downregulation of the HIF-1 signaling pathway at cellular and tissue levels.

CONCLUSION

Our study revealed that QX can significantly reduce the dorsal inflammatory response in the IMQ-induced psoriasis mouse model. Furthermore, we discovered that its main component, shikonin, exerts its therapeutic effect by diminishing the HIF-1 signaling pathway in HaCaT cells.

Tripterygium wilfordii Hook. F. and Its Extracts for Psoriasis: Efficacy and Mechanism

Psoriasis is an inflammatory autoimmune skin condition that is clinically marked by chronic erythema and scaling. The traditional Chinese herb Tripterygium wilfordii Hook. F. (TwHF) is commonly used in the treatment of immune-related skin illnesses, such as psoriasis. In clinical studies, PASI (Psoriasis Area and Severity Index) were dramatically decreased by TwHF and its extracts. Their benefits for psoriasis also include relief from psoriasis symptoms such as itching, dryness, overall lesion scores and quality of life. And the pathological mechanisms include anti-inflammation, immunomodulation and potentially signaling pathway modulations, which are achieved by modulating type-3 inflammatory cytokines including IL-22, IL-23, and IL-17 as well as immune cells like Th17 lymphocytes, γδT cells, and interfering with IFN-SOCS1, NF-κB and IL- 36α signaling pathways. TwHF and its extracts may cause various adverse drug reactions, such as gastrointestinal responses, aberrant hepatocytes, reproductive issues, and liver function impairment, but at adequate doses, they are regarded as an alternative therapy for the treatment of psoriasis. In this review, the effectiveness and mechanisms of TwHF and its extracts in psoriasis treatment are elucidated.

Glycyrol Prevents the Progression of Psoriasis-like Skin Inflammation via Immunosuppressive and Anti-Inflammatory Actions

Glycyrol (GC) is one natural active product. Imiquimod-induced psoriasis-like Balb/c mouse models were established. The model mice were intraperitoneally injected with cyclosporine A (CsA) and GC for 8 days followed by a series of biological detections. GC had little toxicity according to the levels of peripheral blood cells, hemoglobin, blood urea nitrogen (BUN), and serum creatinine (CRE), while CsA significantly increased the levels of BUN and CRE. GC decreased the splenic index and reduced the expressions of IL-6, IL-23, and CXCL-3 in the model mice and IL-6, CXCL-1, and CXCL-2 in the inflammatory HaCaT cells. The half inhibition concentration (IC50) of GC on HaCaT cells was 29.72 μmol/L, resulting in improved apoptosis, enhanced expressions of p21, BAX, and BIK, and reduced expressions of BCL-2. GC is an immunosuppressive agent against psoriasis-like symptoms by anti-inflammatory effects, which provides a strategy for the discovery of anti-psoriatic natural products.

Comprehensive Analysis to Identify Rh Family C Glycoprotein (RHCG) as the Causative Gene for Psoriasis and Search for Alternative Treatment Modalities

Background

Psoriasis is a complex autoimmune disease. Frequent interactions between epidermal and immune cells are likely to be responsible for the strong heterogeneity of psoriasis. Therefore, our work aims to build on current knowledge and further search for new molecular mechanisms related to psoriasis pathogenesis in order to develop new targeted drugs.

Methods

Data from psoriasis samples were obtained from the Gene Expression Omnibus (GEO) database, and batch effects were corrected using the "Combat" algorithm in the "SVA" package. Functional annotation of differential genes in psoriasis was performed by Gene set enrichment analysis (GSEA). Core functional modules were identified using the Multiscale Embedded Gene Co-Expression Network Analysis (MEGENA) algorithm for selection from the differential gene interaction network. The expression and potential function of Rh Family C Glycoprotein (RHCG) was predicted in single cell data by the "Seurat" package and validated in psoriasis samples by multiplex immunofluorescence. In addition, the regulatory function of HOP Homeobox (HOPX) on RHCG in keratinocytes was confirmed using RNA interference. Using immune infiltration analysis, RHCG and DC cells were analyzed for their association. Finally, the molecular mechanisms of treatment of psoriasis using Tripterygii Radix (TR) and Cinnamomi Ramulus (CR) were explored through network pharmacology and experimental validation.

Results

Immune response (represented by C1_2) and collagen matrix formation (represented by C1_3) were identified as two important pathogenic factors in psoriasis and helped to define new biological subtypes of psoriasis. One important psoriasis hub gene, RHCG, was obtained and found to be closely associated with keratinocyte differentiation as well as DC cell maturation. And RHCG was regulated by HOPX in keratinocytes. In addition, the mechanism of action of CR and TR in the treatment of psoriasis was tentatively confirmed to be related to TRPV3, NFKB2, and YAP1.

Conclusions

Our study identifies a new causal disease gene (RHCG) and offers potential alternatives for the treatment of psoriasis.

Discovery of CLEC2B as a diagnostic biomarker and screening of celastrol as a candidate drug for psoriatic arthritis through bioinformatics analysis

BACKGROUND

Psoriatic arthritis (PSA) is a chronic, immune-mediated inflammatory joint disease that is liked to mortality due to cardiovascular disease. Diagnostic markers and effective therapeutic options for PSA remain limited due to the lack of understanding of the pathogenesis. We aimed to identify potential diagnostic markers and screen the therapeutic compounds for PSA based on bioinformatics analysis.

METHODS

Differentially expressed genes (DEGs) of PSA were identified from the GSE61281 dataset. WGCNA was used to identify PSA-related modules and prognostic biomarkers. Clinical samples were collected to validate the expression of the diagnostic gene. These DEGs were subjected to the CMap database for the identification of therapeutic candidates for PSA. Potential pathways and targets for drug candidates to treat PSA were predicted using Network Pharmacology. Molecular docking techniques were used to validate key targets.

RESULTS

CLEC2B was identified as a diagnostic marker for PSA patients (AUC > 0.8) and was significantly upregulated in blood samples. In addition, celastrol was identified as a candidate drug for PSA. Subsequently, the network pharmacology approach identified four core targets (IL6, TNF, GAPDH, and AKT1) of celastrol and revealed that celastrol could treat PSA by modulating inflammatory-related pathways. Finally, molecular docking demonstrated stable binding of celastrol to four core targets in the treatment of PSA. Animal experiments indicated celastrol alleviated inflammatory response in the mannan-induced PSA.

CONCLUSION

CLEC2B was a diagnostic marker for PSA patients. Celastrol was identified as a potential therapeutic drug for PSA via regulating immunity and inflammation.

Langerhans Cells-Revising Their Role in Skin Pathologies

Langerhans cells (LCs) constitute a cellular immune network across the epidermis. Because they are located at the skin barrier, they are considered immune sentinels of the skin. These antigen-presenting cells are capable of migrating to skin draining lymph nodes to prime adaptive immune cells, namely T- and B-lymphocytes, which will ultimately lead to a broad range of immune responses. Moreover, LCs have been shown to possess important roles in the anti-cancer immune responses. Indeed, the literature nicely highlights the role of LCs in melanoma. In line with this, LCs have been found in melanoma tissues where they contribute to the local immune response. Moreover, the immunogenic properties of LCs render them attractive targets for designing vaccines to treat melanoma and autoimmune diseases. Overall, future studies will help to enlarge the portfolio of immune properties of LCs, and aid the prognosis and development of novel therapeutic approaches to treating skin pathologies, including cancers.

Potential effects and mechanisms of Chinese herbal medicine in the treatment of psoriasis

ETHNOPHARMACOLOGICAL RELEVANCE

Psoriasis is a chronic inflammatory dermatosis related to high morbidity and mortality. The incidence of psoriasis is increasing in recent decades. Some patients with psoriasis are anxious about the underlying side effects of synthetic drugs they are on. Therefore, they are eager to seek alternative and efficient therapy, such as Chinese herbal medicine (CHM). Researchers have found some CHM provides best source for the development of anti-psoriatic drugs because of their structural diversity and fewer adverse reactions. Some of CHM formulas or active constituents extracted from CHM have been rapidly developed into clinical drugs with good efficacy. At present, along with the CHM formulas, single CHM and its active components have been extensively accepted and utilized in the treatment of psoriasis, whose therapeutic mechanisms hitherto have not been thoroughly illustrated.

AIM OF THE STUDY

This review aimed to comprehensively summarize about the existing therapeutic mechanisms of CHM in the treatment of psoriasis and to provide a reference to develop future related studies in this field.

MATERIALS AND METHODS

Relevant literatures about how CHM treated psoriasis were acquired from published scientific studies (including PubMed, CNKI, Web of Science, Baidu Scholar, The Plant List, Elsevier and SciFinder). All plants appearing in the review have been included in The Plant List or Medicinal Plant Names Services (MPNS).

RESULTS

In this review, we collect numerous literatures about how CHM treats psoriasis via immune cells, signaling pathways and disease-related mediators and systematically elucidates potential mechanisms from the point of the suppression of oxidative stress, the inhibition of abnormal abnormal proliferation and differentiation, the inhibition of immune responses, and the suppression of angiogenesis.

CONCLUSIONS

Psoriasis is considered as a complicated disease caused by interaction among various mechanisms. The CHM formulas, single CHM and its active components have considerable positive reports about the treatment of psoriasis, which brings hope for a promising future of CHM in the clinical therapy of psoriasis. In the paper, we have concluded that the existing therapeutic mechanisms of CHM in the treatment of psoriasis.