Differential Kinetics of Aspergillus nidulans and Aspergillus fumigatus Phagocytosis.

Invasive aspergillosis mainly occurs in immunocompromised patients and is commonly caused by Aspergillus fumigatus, while A.nidulans is rarely the causative agent. However, in chronic granulomatous disease (CGD) patients, A. nidulans is a frequent cause of invasive aspergillosis and is associated with higher mortality. Immune recognition of A. nidulans was compared to A. fumigatus to offer an insight into why A. nidulans infections are prevalent in CGD. Live cell imaging with J774A.1 macrophage-like cells and LC3-GFP-mCherry bone marrow-derived macrophages (BMDMs) revealed that phagocytosis of A. nidulans was slower compared to A. fumigatus. This difference could be attributed to slower migration of J774A.1 cells and a lower percentage of migrating BMDMs. In addition, delayed phagosome acidification and LC3-associated phagocytosis was observed with A. nidulans. Cytokine and oxidative burst measurements in human peripheral blood mononuclear cells revealed a lower oxidative burst upon challenge with A. nidulans. In contrast, A. nidulans induced significantly higher concentrations of cytokines. Collectively, our data demonstrate that A. nidulans is phagocytosed and processed at a slower rate compared to A. fumigatus, resulting in reduced fungal killing and increased germination of conidia. This slower rate of A. nidulans clearance may be permissive for overgrowth within certain immune settings.

IL-37 protects against obesity-induced inflammation and insulin resistance.

Cytokines of the IL-1 family are important modulators of obesity-induced inflammation and the development of systemic insulin resistance. Here we show that IL-1 family member IL-37, recently characterized as an anti-inflammatory cytokine, ameliorates obesity-induced inflammation and insulin resistance. Mice transgenic for human IL-37 (IL-37tg) exhibit reduced numbers of adipose tissue macrophages, increased circulating levels of adiponectin and preserved glucose tolerance and insulin sensitivity after 16 weeks of HFD. In vitro treatment of adipocytes with recombinant IL-37 reduces adipogenesis and activates AMPK signalling. In humans, elevated steady-state IL-37 adipose tissue mRNA levels are positively correlated with insulin sensitivity and a lower inflammatory status of the adipose tissue. These findings reveal IL-37 as an important anti-inflammatory modulator during obesity-induced inflammation and insulin resistance in both mice and humans, and suggest that IL-37 is a potential target for the treatment of obesity-induced insulin resistance and type 2 diabetes.