The ciliary protein Spef2 stimulates acinar Ampkα/Sirt1 signaling and ameliorates acute pancreatitis and associated lung injury.

BACKGROUND

Pancreatic acinar cells are susceptible to nuclear factor kappa B (NF-κB)-mediated inflammation and resulting cell necrosis during early acute pancreatitis. As adenosine monophosphate-activated protein kinase alpha (Ampkα)/sirtuin 1 (Sirt1) pathway activity attenuates NF-κB activity, we examined whether the Ampkα/Sirt1 axis affects the progression of acute pancreatitis and associated lung injury . Furthermore, we explored the role of the ciliary protein sperm flagellar 2 (Spef2, Kpl2) in regulating Ampkα/Sirt1 activity and .

METHODS

Pancreatic injury, oxidative stress, acinar cell necrosis and apoptosis, acinar levels of Ampkα/Sirt1/NF-κB signaling activity, NF-kB-mediated inflammatory markers, and markers of associated lung injury were measured in rat models of acute pancreatitis following pharmacological Ampkα activation with A769662 or self-complementary recombinant adeno-associated virus serotype 6 (scAAV6)-mediated Spef2 overexpression. Additional rescue studies involving Ampkα silencing and/or constitutively active (CA)-Sirt1 overexpression were performed in acute pancreatitis rats. immunoblotting and Ampkα activity assays were conducted in the pancreatic acinar cell line AR42J.

RESULTS

Pharmacological Ampkα activation or Spef2 overexpression reduced acute pancreatitis severity, oxidative stress, necrosis, apoptosis, NF-kB-mediated inflammatory markers, and the degree of associated lung injury. Spef2 overexpression in AR42J cells promoted Ampkα phosphorylation and Ampkα activity. rescue studies revealed that Spef2's suppressive effect on acute pancreatitis and associated lung injury is mediated via the Ampkα/Sirt1 axis.

CONCLUSIONS

This study established the existence of a Spef2/Ampkα/Sirt1 axis in pancreatic acinar cells that is involved in the regulation of NF-κB-mediated acinar cell inflammation and resulting cell necrosis during acute pancreatitis.