Dataset Information

The Contact Allergen NiSO₄ Triggers a Distinct Molecular Response in Primary Human Dendritic Cells Compared to Bacterial LPS.

ABSTRACT: Dendritic cells (DC) play a central role in the pathogenesis of allergic contact dermatitis (ACD), the most prevalent form of immunotoxicity in humans. However, knowledge on allergy-induced DC maturation is still limited and proteomic studies, allowing to unravel molecular effects of allergens, remain scarce. Therefore, we conducted a global proteomic analysis of human monocyte-derived dendritic cells (MoDC) treated with NiSO₄, the most prominent cause of ACD and compared proteomic alterations induced by NiSO₄ to the bacterial trigger lipopolysaccharide (LPS). Both substances possess a similar toll-like receptor (TLR) 4 binding capacity, allowing to identify allergy-specific effects compared to bacterial activation. MoDCs treated for 24 h with 2.5 μg/ml LPS displayed a robust immunological response, characterized by upregulation of DC activation markers, secretion of pro-inflammatory cytokines and stimulation of T cell proliferation. Similar immunological reactions were observed after treatment with 400 μM NiSO₄ but less pronounced. Both substances triggered TLR4 and triggering receptor expressed on myeloid cells (TREM) 1 signaling. However, NiSO₄ also activated hypoxic and apoptotic pathways, which might have overshadowed initial signaling. Moreover, our proteomic data support the importance of nuclear factor erythroid 2-related factor 2 (Nrf2) as a key player in sensitization since many Nrf2 targets genes were strongly upregulated on protein and gene level selectively after treatment with NiSO₄. Strikingly, NiSO₄ stimulation induced cellular cholesterol depletion 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 essential contribution to the molecular understanding of contact allergy.

SUBMITTER: Hoper T

PROVIDER: S-EPMC7991087 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description: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.

Project description:BackgroundRespiratory infections challenge the swine industry, despite common medicinal practices. The dual signaling nature of PGE2 (supporting both inflammation and resolution) makes it a potent regulator of immune cell function. Therefore, the use of dietary long chain n-6 PUFA to enhance PGE2 effects merits investigation.MethodsDay-old pigs (n = 60) were allotted to one of three dietary groups for 21 d (n = 20/diet), and received either a control diet (CON, arachidonate = 0.5% of total fatty acids), an arachidonate (ARA)-enriched diet (LC n-6, ARA = 2.2%), or an eicosapentaenoic (EPA)-enriched diet (LC n-3, EPA = 3.0%). Alveolar macrophages and lung parenchymal tissue were collected for fatty acid analysis. Isolated alveolar macrophages were stimulated with LPS in situ for 24 h, and mRNA was isolated to assess markers associated with inflammation and eicosanoid production. Culture media were collected to assess PGE2 secretion. Oxidative burst in macrophages was measured by: 1) oxygen consumption and extracellular acidification (via Seahorse), 2) cytoplasmic oxidation and 3) nitric oxide production following 4, 18, and 24 h of LPS stimulation.ResultsConcentration of ARA (% of fatty acids, w/w) in macrophages from pigs fed LC n-6 was 86% higher than CON and 18% lower in pigs fed LC n-3 (P < 0.01). Following LPS stimulation, abundance of COX-2 and TNF-α mRNA (P < 0.0001), and PGE2 secretion (P < 0. 01) were higher in LC n-6 PAM vs. CON. However, ALOX5 abundance was 1.6-fold lower than CON. Macrophages from CON and LC n-6 groups were 4-fold higher in ALOX12/15 abundance (P < 0.0001) compared to LC n-3. Oxygen consumption and extracellular acidification rates increased over 4 h following LPS stimulation (P < 0.05) regardless of treatment. Similarly, increases in cytoplasmic oxidation (P < 0.001) and nitric oxide production (P < 0.002) were observed after 18 h of LPS stimulation but were unaffected by diet.ConclusionsWe infer that enriching diets with arachidonic acid may be an effective means to enhance a stronger innate immunologic response to respiratory challenges in neonatal pigs. However, further work is needed to examine long-term safety, clinical efficacy and economic viability.

Project description:UnlabelledOuter membrane vesicles (OMV) are proposed to mediate multiple functions during pathogenesis and symbiosis. However, the mechanisms responsible for OMV formation remain poorly understood. It has been shown in eukaryotic membranes that lipids with an inverted-cone shape favor the formation of positive membrane curvatures. Based on these studies, we formulated the hypothesis that lipid A deacylation might impose shape modifications that result in the curvature of the outer membrane (OM) and subsequent OMV formation. We tested the effect of lipid A remodeling on OMV biogenesis employing Salmonella enterica serovar Typhimurium as a model organism. Expression of the lipid A deacylase PagL resulted in increased vesiculation, without inducing an envelope stress response. Mass spectrometry analysis revealed profound differences in the patterns of lipid A in OM and OMV, with accumulation of deacylated lipid A forms exclusively in OMV. OMV biogenesis by intracellular bacteria upon macrophage infection was drastically reduced in a pagL mutant strain. We propose a novel mechanism for OMV biogenesis requiring lipid A deacylation in the context of a multifactorial process that involves the orchestrated remodeling of the outer membrane.ImportanceThe role of lipid remodeling in vesiculation is well documented in eukaryotes. Similarly, bacteria produce membrane-derived vesicles; however, the molecular mechanisms underlying their production are yet to be determined. In this work, we investigated the role of outer membrane remodeling in OMV biogenesis in S Typhimurium. We showed that the expression of the lipid A deacylase PagL results in overvesiculation with deacylated lipid A accumulation exclusively in OMV. An S Typhimurium ΔpagL strain showed a significant reduction in intracellular OMV secretion relative to the wild-type strain. Our results suggest a novel mechanism for OMV biogenesis that involves outer membrane remodeling through lipid A modification. Understanding how OMV are produced by bacteria is important to advance our understanding of the host-pathogen interactions.

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

Tweets

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

Tweets

The Contact Allergen NiSO₄ Triggers a Distinct Molecular Response in Primary Human Dendritic Cells Compared to Bacterial LPS.