Transcriptome-wide analysis of filarial extract-primed human monocytes reveal changes in LPS-induced PTX3 expression levels

High-fat diet-induced obesity affects alpha 7 nicotine acetylcholine receptor expressions in mouse lung myeloid cells

Ample evidence indicates that obesity causes dysfunctions in the lung. Previous studies also show that cholinergic anti-inflammatory pathways play crucial roles in obesity-induced chronic inflammation via α7 nicotinic acetylcholine receptor (α7nAChR) signaling. However, it remains unclear whether and how obesity affects the expressions of α7nAChR in myeloid cells in the lung. To address this question, we treated regular chow diet-fed mice or high-fat diet induced obese mice with lipopolysaccharide (LPS) or vehicle via endotracheal injections. By using a multicolor flow cytometry approach to analyze and characterize differential cell subpopulations and α7nAChR expressions, we find no detectable α7nAChR in granulocytes, monocytes and alveolar macrophages, and low expression levels of α7nAChR were detected in interstitial macrophages. Interestingly, we find that a challenge with LPS treatment significantly increased expression levels of α7nAChR in monocytes, alveolar and interstitial macrophages. Meanwhile, we observed that the expression levels of α7nAChR in alveolar and interstitial macrophages in high-fat diet induced obese mice were lower than regular chow diet-fed mice challenged by the LPS. Together, our findings indicate that obesity alters the expressions of α7nAChR in differential lung myeloid cells.

TGFβ depletion does neither modulate acute E. coli-induced inflammatory immune responses nor impair the protective effect by chronic filarial infection

TGFβ is an anti-inflammatory molecule that suppresses pro-inflammatory immune responses. Previously, we demonstrated that chronic filarial infection has a beneficial impact on Escherichia coli-induced sepsis. In the present study, we investigated whether this protective effect is dependent on TGFβ signaling and whether depletion of TGFβ before E. coli challenge alters the early course of sepsis per se. In vivo depletion of TGFβ before E. coli challenge did not alter levels of pro-inflammatory cytokines/chemokines and did neither increase the bacterial burden nor worsen E. coli-induced hypothermia six hours post E. coli challenge. Similarly, in the co-infection model, despite TGFβ depletion, mice infected with the filarial nematode Litomosoides sigmodontis exhibited milder E. coli-induced hypothermia, reduced bacterial load and pro-inflammatory immune responses. Thus, we conclude that TGFβ is not essentially modulating the initial pro-inflammatory phase during sepsis and that the protective effect of a chronic filarial infection against sepsis is independent of TGFβ signaling.