Dendritic Cell-Derived TSLP Negatively Regulates HIF-1α and IL-1β During Dectin-1 Signaling

TSLP/TSLPR promotes renal fibrosis by activating STAT3 in renal fibroblasts

Previous studies have demonstrated the importance of TSLP-TSLPR in inflammatory, allergic, and fibrotic diseases. However, their exact molecular mechanism in regulating renal fibrosis has not been fully explored yet. The current study identified the high expression levels of TSLP and TSLPR in human and mouse hydronephrotic tissues. In addition, immunofluorescence staining showed that TSLP was highly expressed in renal tubular cells, while TSLPR was mainly co-localized with α-SMA, a marker of fibroblasts. Knocking out TSLPR in the UUO model could alleviate the severity of renal fibrosis. Most importantly, the application of antibody blockade of TSLP reduced the fibrotic level in the UUO model. The functional analysis revealed that the hypoxic exposure could induce the overexpression of TSLP in renal tubular cells via HIF-1α. The tubular cell-derived TSLP could bind to the TSLPR of fibroblasts in a paracrine manner to activate them. Specifically, the HIF-1α/TSLP/TSLPR-axis could activate fibroblasts through the STAT3 signaling pathway. This study revealed a mechanistic interaction of HIF-1α/TSLP/TSLPR and STAT3 signaling pathways in the activation and proliferation of human and murine kidney fibroblasts; these pathways might be exploited as a therapeutic target in renal fibrosis.

Construction and verification of atopic dermatitis diagnostic model based on pyroptosis related biological markers using machine learning methods

OBJECTIVE

The aim of this study was to construct a model used for the accurate diagnosis of Atopic dermatitis (AD) using pyroptosis related biological markers (PRBMs) through the methods of machine learning.

METHOD

The pyroptosis related genes (PRGs) were acquired from molecular signatures database (MSigDB). The chip data of GSE120721, GSE6012, GSE32924, and GSE153007 were downloaded from gene expression omnibus (GEO) database. The data of GSE120721 and GSE6012 were combined as the training group, while the others were served as the testing groups. Subsequently, the expression of PRGs was extracted from the training group and differentially expressed analysis was conducted. CIBERSORT algorithm calculated the immune cells infiltration and differentially expressed analysis was conducted. Consistent cluster analysis divided AD patients into different modules according to the expression levels of PRGs. Then, weighted correlation network analysis (WGCNA) screened the key module. For the key module, we used Random forest (RF), support vector machines (SVM), Extreme Gradient Boosting (XGB), and generalized linear model (GLM) to construct diagnostic models. For the five PRBMs with the highest model importance, we built a nomogram. Finally, the results of the model were validated using GSE32924, and GSE153007 datasets.

RESULTS

Nine PRGs were significant differences in normal humans and AD patients. Immune cells infiltration showed that the activated CD4+ memory T cells and Dendritic cells (DCs) were significantly higher in AD patients than normal humans, while the activated natural killer (NK) cells and the resting mast cells were significantly lower in AD patients than normal humans. Consistent cluster analysis divided the expressing matrix into 2 modules. Subsequently, WGCNA analysis showed that the turquoise module had a significant difference and high correlation coefficient. Then, the machine model was constructed and the results showed that the XGB model was the optimal model. The nomogram was constructed by using HDAC1, GPALPP1, LGALS3, SLC29A1, and RWDD3 five PRBMs. Finally, the datasets GSE32924 and GSE153007 verified the reliability of this result.

CONCLUSIONS

The XGB model based on five PRBMs can be used for the accurate diagnosis of AD patients.

C-type lectin receptors in antifungal immunity: Current knowledge and future developments

C-type lectin receptors (CLRs) constitute a category of innate immune receptors that play an essential role in the antifungal immune response. For over two decades, scientists have uncovered what are the fungal ligands recognized by CLRs and how these receptors initiate the immune response. Such studies have allowed the identification of genetic polymorphisms in genes encoding for CLRs or for proteins involved in the signalisation cascade they trigger. Nevertheless, our understanding of how these receptors functions and the full extent of their function during the antifungal immune response is still at its infancy. In this review, we summarize some of the main findings about CLRs in antifungal immunity and discuss what the future might hold for the field.

A population of dermal Langerin+ dendritic cells promote the inflammation in mouse model of atopic dermatitis

Cutaneous dendritic cells (DCs) have been implicated in the pathogenesis of atopic dermatitis (AD). However, the specific role of different subsets of DCs has not been well defined. This study aimed to investigate the contributions of Langerhans cells (LCs), resident dermal Langerin⁺ DCs (r-Langerin⁺ dDCs), and newly infiltrated inflammatory dermal Langerin⁺ DCs (i-Langerin⁺ dDCs) in an AD mouse model induced by the topical application of MC903. The result showed that depletion of i-Langerin⁺ dDCs in DTR mice after multiple diphtheria toxin (DT) injection significantly reduced thymic stromal lymphopoietin (TSLP) production in lesions and skin inflammation alleviation. However, depletion of LCs or r-Langerin⁺ dDCs didn’t resulted in significant changes in skin inflammation of DTA or single DT injection-treated DTR mice compared with the wild-type (WT) mice. DT-treated DTR-WT chimeric mice with the depletion of bone marrow (BM)-derived i-Langerin⁺ dDCs resulted in markedly decreased skin inflammation than controls, while PBS-treated chimeric mice (DTR-WT) with only the depletion of r-Langerin⁺ dDCs showed inflammation comparable to that in WT mice. Furthermore, TSLP contributed to the upregulation of Langerin expression in BM-derived DCs and promoted the maturation of Langerin⁺ DCs. In summary, the present study demonstrated that the newly infiltrated inflammatory dermal Langerin⁺ DCs were essential for AD development and local TSLP production, and TSLP further promoted the production of BM-derived i-Langerin⁺ dDCs, which might maintain AD inflammation.

TSLP promoting B cell proliferation and polarizing follicular helper T cell as a therapeutic target in IgG4-related disease

OBJECTIVE

To figure out the functions of thymic stromal lymphopoietin (TSLP) in IgG4-related disease (IgG4-RD).

METHODS

Plasma TSLP levels were tested by Elisa, and its receptors were detected by flow cytometry. Expressions of TSLP and TSLPR in involved tissues were stained by immunohistochemistry and immunofluorescence. Proliferation, apoptosis, and B subsets of TSLP stimulated-B cells were analyzed by flow cytometry. TSLP-stimulated B cells were co-cultured with CD4+ Naïve T cells. Signaling pathway was identified by RNA-sequencing and western blot. Anti-TSLP therapy was adapted in LatY136F knock-in mice (Lat, IgG4-RD mouse model).

RESULTS

Plasma TSLP level was increased in IgG4-RD patients and was positively correlated with serum IgG4 level and responder index (RI). TSLPR was co-localized with CD19+ B cells in the submandibular glands (SMGs) of IgG4-RD. TSLP promoted B cell proliferation, and TSLP-activated B cells polarized CD4+ naive T cells into follicular helper T (Tfh) cells through OX40L. RNA-sequencing identified JAK-STAT signaling pathway in TSLP-activated B cells and it was verified by western blot. Anti-TSLP therapy alleviated the inflammation of lung in Lat mice.

CONCLUSION

Elevated TSLP in IgG4-RD promoted B cells proliferation and polarized Tfh cells and might be served as a potential therapeutic target.

Angiogenesis, Lymphangiogenesis, and Inflammation in Chronic Obstructive Pulmonary Disease (COPD): Few Certainties and Many Outstanding Questions

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation, predominantly affecting the lung parenchyma and peripheral airways, that results in progressive and irreversible airflow obstruction. COPD development is promoted by persistent pulmonary inflammation in response to several stimuli (e.g., cigarette smoke, bacterial and viral infections, air pollution, etc.). Angiogenesis, the formation of new blood vessels, and lymphangiogenesis, the formation of new lymphatic vessels, are features of airway inflammation in COPD. There is compelling evidence that effector cells of inflammation (lung-resident macrophages and mast cells and infiltrating neutrophils, eosinophils, basophils, lymphocytes, etc.) are major sources of a vast array of angiogenic (e.g., vascular endothelial growth factor-A (VEGF-A), angiopoietins) and/or lymphangiogenic factors (VEGF-C, -D). Further, structural cells, including bronchial and alveolar epithelial cells, endothelial cells, fibroblasts/myofibroblasts, and airway smooth muscle cells, can contribute to inflammation and angiogenesis in COPD. Although there is evidence that alterations of angiogenesis and, to a lesser extent, lymphangiogenesis, are associated with COPD, there are still many unanswered questions.

Hypoxia/HIF Modulates Immune Responses

Oxygen availability varies throughout the human body in health and disease. Under physiological conditions, oxygen availability drops from the lungs over the blood stream towards the different tissues into the cells and the mitochondrial cavities leading to physiological low oxygen conditions or physiological hypoxia in all organs including primary lymphoid organs. Moreover, immune cells travel throughout the body searching for damaged cells and foreign antigens facing a variety of oxygen levels. Consequently, physiological hypoxia impacts immune cell function finally controlling innate and adaptive immune response mainly by transcriptional regulation via hypoxia-inducible factors (HIFs). Under pathophysiological conditions such as found in inflammation, injury, infection, ischemia and cancer, severe hypoxia can alter immune cells leading to dysfunctional immune response finally leading to tissue damage, cancer progression and autoimmunity. Here we summarize the effects of physiological and pathophysiological hypoxia on innate and adaptive immune activity, we provide an overview on the control of immune response by cellular hypoxia-induced pathways with focus on the role of HIFs and discuss the opportunity to target hypoxia-sensitive pathways for the treatment of cancer and autoimmunity.

Antitumor effect of soluble β-glucan as an immune stimulant

β-glucans are linear polysaccharides of d-glucose monomers linked through β-glycosidic bonds and are widely present in nature. Different sources lead to their structural differences. β-glucan has long been acknowledged to be a safe and functional component. Its biological activities include lipid-lowering, hypoglycemic, antitumor and immune regulation etc. A large number of studies have shown that soluble β-glucan can bind to their receptors on the surface of immune cells, activates the pro-inflammatory response of innate immune cells, and enhances the host's antitumor defense. A variety of soluble β-glucans have been widely used in clinical antitumor studies as an immunostimulant to treat the cancer patient. In this paper, we reviewed the molecular structure, antitumor immune activities, structure-activity relationship and clinical trials of soluble β-glucans in order to provide the overall scene of β-glucans as immunostimulant to fight the cancer.

Dibutyl phthalate induces allergic airway inflammation in rats via inhibition of the Nrf2/TSLP/JAK1 pathway

Dibutyl phthalate (DBP), an important plastic contaminant in the environment, is known to cause organ toxicity. Although current research has shown that DBP-induced organ toxicity is associated with oxidative stress, the toxic effect of DBP on the lungs have not been fully elucidated. Therefore, we investigated the potential mechanism by which DBP induces pulmonary toxicity using a model of DBP-induced allergic airway inflammation in rats. The results showed that chronic exposure to DBP induced histopathological damage, inflammation, oxidative stress, apoptosis, and increased the protein levels of thymic stromal lymphopoietin (TSLP) and its downstream protein Janus kinase 1 (JAK1) and signal transducer and activator of transcription 6 (STAT6). Moreover, DBP exposure inhibited nuclear factor-erythroid-2-related factor 2 (Nrf2) and levels of its target genes NAD(P)H quinone oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1). Additionally, using in vitro experiments, we found that DBP induced oxidative stress, reduced cell viability, and inhibited the Nrf2/HO-1/NQO1 pathway in mouse alveolar type II epithelial cell line. Overall, these data demonstrate that DBP induces allergic airway inflammation in rats via inhibition of the Nrf2/TSLP/JAK1 pathway.

The Expressions of TSLP, IL-33, and IL-17A in Monocyte Derived Dendritic Cells from Asthma and COPD Patients are Related to Epithelial-Macrophage Interactions

BACKGROUND

The cross-talk between the external and internal environment in the respiratory tract involves macrophage/dendritic cell (DC) transepithelial network. Epithelium triggers dendritic cell-mediated inflammation by producing thymic stromal lymphopoietin (TSLP), IL-33, and IL-17A. The study aimed to evaluate the expression of TSLP, IL-33, and IL-17A in human monocyte derived dendritic cells (moDCs) co-cultured with respiratory epithelium and monocyte derived macrophages (moMφs) in asthma, chronic obstructive pulmonary disease (COPD) and healthy controls.

METHODS

The study used a triple-cell co-culture model, utilizing nasal epithelial cells, along with moMφs and moDCs. Cells were cultured in mono-, di-, and triple-co-cultures for 24 h.

RESULTS

Co-culture with epithelium and moMφs significantly increased TSLP in asthma and did not change IL-33 and IL-17A mRNA expression in moDCs. moDCs from asthmatics were characterized by the highest TSLP mRNA expression and the richest population of TSLPR, ST2, and IL17RA expressed cells. A high number of positive correlations between the assessed cytokines and CHI3L1, IL-12p40, IL-1β, IL-6, IL-8, TNF in moDCs was observed in asthma and COPD.

CONCLUSION

TSLP, IL-33, and IL-17A expression in moDCs are differently regulated by epithelium in asthma, COPD, and healthy subjects. These complex cell-cell interactions may impact airway inflammation and be an important factor in the pathobiology of asthma and COPD.