Abstract
Translocation of gut bacteria into the pancreas promotes the development of severe acute pancreatitis (SAP). Recent clinical studies have also highlighted the association between fungal infections and SAP. The sensing of gut bacteria by pattern recognition receptors promotes the development of SAP via the production of proinflammatory cytokines; however, the mechanism by which gut fungi mediate SAP remains largely unknown. Leucine-rich repeat kinase 2 (LRRK2) is a multifunctional protein that regulates innate immunity against fungi via Dectin-1 activation. Here, we investigated the role of LRRK2 in SAP development and observed that administration of LRRK2 inhibitors attenuated SAP development. The degree of SAP was greater in Lrrk2 transgenic (Tg) mice than in control mice and was accompanied by an increased production of nuclear factor-kappaB-dependent proinflammatory cytokines. Ablation of the fungal mycobiome by anti-fungal drugs inhibited SAP development in Lrrk2 Tg mice, whereas the degree of SAP was comparable in Lrrk2 Tg mice with or without gut sterilization by a broad range of antibiotics. Pancreatic mononuclear cells from Lrrk2 Tg mice produced large amounts of IL-6 and TNF-α upon stimulation with Dectin-1 ligands, and inhibition of the Dectin-1 pathway by a spleen tyrosine kinase inhibitor protected Lrrk2 Tg mice from SAP. These data indicate that LRRK2 activation is involved in the development of SAP through proinflammatory cytokine responses upon fungal exposure.