Autocrine Sonic Hedgehog Attenuates Inflammation in Cerulein-Induced Acute Pancreatitis in Mice via Upregulation of IL-10

Hedgehog signaling plays critical roles in pancreatic oncogenesis and chronic pancreatitis, but its roles in acute pancreatitis (AP) are largely ambiguous. In this study, we provide evidence that Sonic hedgehog (Shh), but neither Desert hedgehog (Dhh) nor Indian hedgehog (Ihh), is the main protein whose expression is activated during the development of ceruleininduced acute pancreatitis in mice, and the Shh serves as an anti-inflammation factor in an autocrine manner. Blocking autocrine Shh signaling with anti-Shh neutralizing antibody aggravates the progression of acute pancreatitis. Mechanistic insight into Shh signaling activation in acute pancreatitis indicates that inflammatory stimulation activates Shh expression and secretion, and subsequently upregulates the expression and secretion of interleukin-10 (IL-10). Moreover, inhibition of Shh signaling with neutralizing antibody abolishes IL-10 production in vivo and in vitro. Molecular biological studies show that autocrine Shh signaling activates the key transcriptional factor Gli1 so that the target gene IL-10 is upregulated, leading to the protective and anti-inflammatory functions in the mouse model of acute pancreatitis. Thus, this study suggests autocrine Shh signaling functions as a protective signaling in the progression of acute pancreatitis.