Dataset Information

The contact allergen NiSO4 triggers a distinct molecular response in primary human dendritic cells compared to bacterial LPS

ABSTRACT: Allergic contact dermatitis (ACD) is the most prevalent form of immunotoxicity in humans. Dendritic cells (DC) play a central role in the pathogenesis of ACD, particularly during the sensitization phase to a specific allergen. Upon activation, DCs maturate and migrate to draining lymph nodes which is accompanied by major metabolic and phenotypic alterations that facilitate the presentation of the captured antigen to prime naïve T cells. Nevertheless, knowledge on the molecular effects during maturation of DCs in the context of ACD remain scarce. Here, we present a global proteomic analysis of monocyte-derived dendritic cells (MoDC) treated with NiSO4, the most prominent cause of ACD. Proteomic alterations induced after treatment with NiSO4 were compared to the bacterial trigger lipopolysaccharide (LPS). Both substances possess a similar TLR4 binding capacity, which may help to identify allergy-specific effects compared to bacterial activation. MoDCs treated for 24 h with 2.5 µg/ ml LPS displayed a very strong immunological response, characterized by upregulation of DC activation markers, secretion of proinflammatory cytokines and stimulation of T cell proliferation. Similar immunological responses were observed after treatment with 400 µM NiSO4 but less pronounced. Both triggered TLR4 and TREM1 pathways. However, NiSO4 in addition, also activated hypoxic and apoptotic pathways, which might have overshadowed initial signaling. Moreover, our proteomic data support the importance of Nrf2 as a key player in mediating sensitization since many Nrf2 targets genes were strongly upregulated on protein level selectively after treatment with NiSO4. Strikingly, NiSO4 stimulation induced cellular hypocholesterolemia which was counteracted by the induction of genes and proteins relevant for cholesterol biosynthesis. Our proteomic study allowed for the first time to better characterize some of the fundamental differences between NiSO4 and LPS-triggered activation of MoDCs, providing an important contribution to the molecular understanding of contact allergy.

INSTRUMENT(S): Q Exactive HF

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Dendritic Cell, Blood

DISEASE(S): Nickel Allergic Contact Dermatitis

SUBMITTER: Kristin Schubert

LAB HEAD: Kristin Schubert

PROVIDER: PXD022599 | Pride | 2021-03-29

REPOSITORIES: Pride

ACCESS DATA

Similar Datasets

Project description:Dendritic cells (DCs) are a special class of leukocytes able to activate both innate and adaptive immune responses. They interact with microbes through germline-encoded pattern-recognition receptors (PRRs), which recognize molecular patterns expressed by various microorganisms. Upon antigen binding, PRRs instruct DCs for the appropriate priming of natural killer cells, followed by specific T-cell responses. Once completed the effector phase, DCs reach the terminal differentiation stage and eventually die by apoptosis. We have observed that following lipopolysaccharide (LPS)-stimulation the initiation of the apoptotic pathway in DCs is due the activation of NFAT proteins. Indeed, LPS induces Src-family kinase and phospholipase C (PLC)Î³2 activation, influx of extracellular Ca2+ and calcineurin-dependent nuclear NFAT translocation. The initiation of this pathway is independent of TLR4 engagement, and dependent exclusively on CD14. According with this observation CD14-deficient DCs do not die following LPS stimulation. Nevertheless, CD14-deficient DC death following LPS activation can be restored by co-stimulating DCs with LPS and thapsigargin. Thapsigargin empties the intracellular calcium stores by blocking calcium pumping into the sarcoplasmic and endoplasmic reticulum and thereby activates plasma membrane calcium channels. This, in turn, allows an influx of calcium into the cytosol and NFAT activation. To identify the NFAT controlled apoptosis genes in LPS activated DCs we have performed a kinetic microarray analysis (0, 48 and 60 h) in conditions allowing or inhibiting NFAT activation. Four genes have been selected: Nur77, Gadd45g, Ddit3/Gadd153/Chop-10 and Tia1. To identify apoptosis genes selectively modulated by NFAT, a comparative kinetic (time points 0, 48 and 60 h) microarray analysis was performed in the following conditions: 1) wild type bone marrow derived DCs (wtBMDCs) stimulated with LPS; 2) CD14-deficient BMDCs stimulated with LPS; 3) wtBMDCs stimulated with LPS in presence of thapsigargin; 4) CD14-deficient BMDCs stimulated with LPS in presence of thapsigargin.

Project description:Pro-inflammation triggered by microbial lipopolysaccharide (LPS) through Toll-like receptor (TLR) 4 in the presence of interferon (IFN)-g induces cytokine secretion in dendritic cells (DCs) tightly regulated by a defined differentiation program. This DC differentiation is characterized by a dynamic immune activating but also tolerance inducing phenotype associated with irreversible down-modulation of cytokines. CD40L on activated T cells further modifies DC differentiation. Using DNA micro arrays we showed down-regulated mRNA levels of TLR signaling molecules while CD40/CD40L signaling molecules were up-regulated at a time when LPS/IFN-g activated DCs have ceased cytokine expression. Accordingly we demonstrated that CD40/CD40L but not TLR4 or TLR3 signaling mediated by LPS or poly (cytidylic-inosinic) acid (poly I:C) and dsRNA re-established the capacity to secret interleukin (IL)-12 in LPS/IFN-g activated DCs, which have exhausted their potential for cytokine secretion. This resulting TH1 polarizing DC phenotype â which lacked accompanying secretion of the crucial immune suppressive IL-10 - enhanced activation of cytotoxic T lymphocytes (CTLs). We therefore conclude that immune modulation is restricted to a secondary T-cell mediated stimulus at an exhausted DC state which prevents an immune tolerant DC phenotype. These findings impacts on the rational design of TLR activated DC-based cancer vaccines for the induction of anti-tumoral CTL responses. Experiment Overall Design: Monocyte derived DCs were matured for 6 hours with 30 ng/ml lipopolysaccharide (LPS, E. coli strain O111:B4, Calbiochem, San Diego, CA) and 1.000 U/ml IFN-g (Imukin, Boehringer Ingelheim, Austria). RNA of DCs was isolated after 6, 12, 24, or 48 hours of maturation using the RNeasy kit (Qiagen, Hilden, Germany) and analyzed by the RZPD (German Resource Centre for Genome Research, Berlin) using the Affymetrix DNA micro array platform (U133 plus 2.0). DNA array data from different maturation-time experiments were compared to controls that were kept in culture for the same time without stimulation.

Dataset Information

The contact allergen NiSO4 triggers a distinct molecular response in primary human dendritic cells compared to bacterial LPS

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure