GRN and acute respiratory distress syndrome: Previous study showed that during inflammation, neutrophils, and macrophages released proteases which digested PGRN into individual 6 kDa granulin units, which were actually proinflammatory and could neutralize the anti-inflammatory effects of intact PGRN [23, 24], which might partly explain the decreased level of PGRN protein in BAL fluid of LPS-induced ALI mice.