Acinar Cell NLRP3 Inflammasome and GSDMD Activation Mediates Pyroptosis and Systemic Inflammation in Acute Pancreatitis

Abstract

Background: Pyroptosis is a lytic form of proinflammatory cell death characterised as caspase-1-dependent with canonical NLRP3 inflammasome-induced gasdermin D (GSDMD) activation. We aimed to investigate the role of acinar pyroptotic cell death in pancreatic injury and systemic inflammation in acute pancreatitis (AP). Methods: Pancreaticacinar pyroptotic cell death pathway activation upon pancreatic toxin stimulation in vitro and in vivo were investigated.Effects of pharmacological (NLRP3 and caspase-1 inhibitors), constitutive (Nlrp3-/-, Caspase-1-/- and Gsdmd-/-) and acinar cell conditional (Pdx1CreNlrp3Δ/Δ and Pdx1CreGsdmd Δ/Δ) genetic inhibition on acinar pyroptotic cell death, pancreatic necrosis and systemic inflammation were assessed using mouse AP models (caerulein, sodium taurocholate, L-arginine). Effects of Pdx1CreGsdmd Δ/Δ vs a myeloid conditional knockout (Lyz2CreGsdmdf/f) and Gsdmd-/- vsreceptor interacting protein 3(RIP3) inhibitor were compared in caerulein-induced AP (CER-AP). Findings: There was consistent acinar pyroptotic cell death activation upon pancreatic toxin stimulation both in vitro and in vivo which was significantly reduced by pharmacological or genetic pyroptosis inhibition. Pdx1CreGsdmd Δ/Δ) but not Lyz2 Cre Gsdmd f/f mice significantly reduced acinar pyroptotic cell death, pancreatic necrosis and systemic inflammation in CER-AP. Co-application of RIP3 inhibitor on Gsdmd-/- mice further increased protection on CER-AP. Interpretation: This work demonstrates a critical role for acinar NLRP3 inflammasome and GSDMD activation-mediated pyroptosis, linking pancreatic necrosis and systemic inflammation in AP. Targeting pyroptosis signalling pathways holds promise for specific AP therapy. Funding Statement: This work was supported by National Natural Science Foundation of China (No. 81570584, No. 81801970, No. 81670588), Key Research and Development Programme Foundation of Jiangsu Province of China (No. BE2015685, No. BE2016749) Declaration of Interests: The authors declare no competing financial interests in relation to the work described. Ethics Approval Statement: All animal procedures were assessed and authorised by the Ethics Committee of Jinling Hospital of Nanjing University (No. 20160905). Human pancreatic sample collection was approved by the Human Ethics Committee of Jinling hospital (No. 2018NZKY009-01).