Aryl Hydrocarbon Receptor is Involved in the Proinflammatory Cytokine Response to Cadmium.

OBJECTIVE: To investigate involvement of the aryl hydrocarbon receptor (AhR) in the immunomodulatory effects of cadmium (Cd). METHODS: The effect of Cd on AhR activation ( CYP1A1 and CYP1B1 mRNA expression) was examined in lung leukocytes of Cd-exposed rats (5 and 50 mg/L, 30 d orally) and by in vitro leukocyte exposure. The involvement of AhR signaling in the effects of Cd on the interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF) lung leukocyte response was investigated in vitro using the receptor antagonist CH-223191. RESULTS: Cd increased CYP1B1 ( in vivo and in vitro) and CYP1A1 ( in vitro) mRNA, indicating AhR involvement in the action of Cd. In response to Cd, lung leukocytes increased IL-6 and decreased TNF at the gene expression and protein levels, but decreased IL-1ß production due to reduced NLRP3. The AhR antagonist CH-223191 abrogated the observed effects of Cd on the cytokine response. The absence of AhR reactivity and cytokine response to Cd of leukocytes from the lungs of a rat strain that is less sensitive to Cd toxicity coincided with a high AhR repressor mRNA level. CONCLUSION: AhR signaling is involved in the lung leukocyte proinflammatory cytokine response to Cd. The relevance of the AhR to the cytokine response to Cd provides new insight into the mechanisms of Cd immunotoxicity.

Aryl Hydrocarbon Receptor is Involved in the Proinflammatory Cytokine Response to Cadmium / 生物医学与环境科学（英文）

Objective@#To investigate involvement of the aryl hydrocarbon receptor (AhR) in the immunomodulatory effects of cadmium (Cd).@*Methods@#The effect of Cd on AhR activation ( @*Results@#Cd increased @*Conclusion@#AhR signaling is involved in the lung leukocyte proinflammatory cytokine response to Cd. The relevance of the AhR to the cytokine response to Cd provides new insight into the mechanisms of Cd immunotoxicity.

Strain differences in the immune mechanisms of resistance of immunocompetent rats to pulmonary aspergillosis.

Although the relevance of genetically-based variations in susceptibility to pulmonary aspergillosis was shown in immunocompromised mice and is indicated in humans, there is virtually no information concerning variations in antifungal immune responses in resistant individuals. We have shown recently the relevance of proinflammatory cytokine (interferon-γ/IFN-γ and interleukin-17/IL-17) responses in resistance to sublethal Aspergillus fumigatus infection of non-suppressed Dark Agouti (DA) rats (strain known of a substantial immune reactivity to noxious insults). In this study, anti-fungal immune activities of leukocytes recovered from lungs by enzyme digestion (phagocytosis, oxidative activity, hyphal killing, CD11b expression, as well as production of IFN-γ, IL-17 and Th2/anti-inflammatory cytokines interleukin-4/IL-4 and interleukin-10/IL-10) were investigated in less reactive Albino Oxford (AO) and compared to DA rats. Elimination of fungus from lungs of AO rats was associated with lower degree of leukocyte infiltration and of the majority of their basic effector activities in comparison to DA rats. Lower production of IFN-γ by pulmonary leukocytes was observed early (day 1) post infection (p.i.) in AO compared to DA rats, but without changes in IL-4. Both strains responded to infection by an increase of IL-17 and IL-10, but production of cytokines was higher (from days 7 p.i. and 3 p.i. for IL-17 and IL-10, respectively) in AO compared to DA rats. The levels and pattern of IFN-γ and IL-4 responses by draining lymph node (dLN) cells were similar in both strains and basically corresponded to those of lung leukocytes. In contrast, similar levels of draining lymph node cell production of IL-17 and IL-10 were observed in both strains with lack of changes in mRNA, what suggests additional stimulation of these cytokines in lungs of AO rats. The knowledge of strain differences in the immune-based strategies in response of immunocompetent hosts to A. fumigatus might contribute to our understanding of variations in underlying mechanisms that enable of resistance to this fungus.