Inhibition of RIPK1-dependent regulated acinar cell necrosis provides protection against acute pancreatitis via the RIPK1/NF-κB/AQP8 pathway

Peng-Yu Duan,Wang-Jun Zhang,Liang Ji,Gang Wang,Bei Sun,Yuan Ma,Fan Xiao,Xiao-Yu Guo,Ji-Sheng Hu,Le Li,Xi-Na Li,Feng-Zhi Qu

doi:10.1038/s12276-019-0278-3

Abstract

Currently, preliminary results have confirmed the existence of receptor-interacting protein kinase 3 (RIPK3) and mixed lineage kinase domain-like protein (MLKL)-dependent necroptosis of pancreatic acinar cells during early acute pancreatitis (AP), which might be a potential target for the effective regulation of necroinflammatory injury. However, the exact effect of receptor-interacting protein kinase 1 (RIPK1)-dependent regulated acinar cell necrosis on AP is still uncertain. In our study, we first explored the changes in the degree of local and systemic inflammation in AP rats when the activation of acinar cell RIPK1 was inhibited. The RIPK1 inhibitor Nec-1 was used to treat rats, and the levels of related inflammatory markers, necrosis indicators and apoptotic indicators were measured. Changes in pancreatic nuclear factor κB (NF-κB) and aquaporin 8 (AQP8) expression were noted. Next, the expression of AQP8 in AR42J cells was inhibited, and the degree of cell necrosis and inflammatory damage was found to be significantly reduced. Most importantly, we demonstrated that the RIPK1/NF-ĸB/AQP8 axis might be a potential regulatory pathway mediating RIPK1-dependent regulated acinar cell necrosis in early AP. Finally, we used the NF-κB inhibitor PDTC and Nec-1 to treat rats in different groups and measured the degree of pathological pancreatic injury, the activation of RIPK1, and the expression of NF-κB and AQP8. In summary, we hypothesized that there might be a RIPK1/NF-ĸB/AQP8 pathway controlling RIPK1-dependent regulated necrosis of acinar cells in AP, which might be a promising therapeutic target against AP-related injury.

Highlights

Acute pancreatitis (AP) is a dangerous and lethal acute abdominal disease with high mortality
The content of ATP in the pancreas of AP + Nec-1 group rats was significantly increased compared with that in AP group rats, but there was no significant difference between the AP + DMSO group and the AP group (Fig. 1d)
To observe the classic receptor-interacting protein kinase 1 (RIPK1)/receptor-interacting protein kinase 3 (RIPK3)/mixed lineage kinase domain-like protein (MLKL) necroptosis pathway in AP rats, RIPK1, RIPK3, and MLKL phosphorylation was assessed by Western blotting, and we found that the RIPK1 phosphorylation levels significantly decreased after treatment with Nec-1, while those of RIPK3 and MLKL did not change appreciably (Fig. 4e, f), which meant that the classic necroptosis pathway was not affected

Summary

Introduction

Acute pancreatitis (AP) is a dangerous and lethal acute abdominal disease with high mortality. Necrosis has been considered to have no important research significance in disease treatment and has not received adequate attention. A programmed form of cell necrosis, regulated necrosis, has become an important research topic in the fields of inflammation and immune diseases and resulting in a breakthrough in the knowledge and understanding about cell death[5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]. The discovery of necroptosis might provide a potential target for effectively controlling inflammatory lesions and improving disease outcomes for typical necrosis-related diseases

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