ORM2 alleviates pancreatic fibrosis in chronic pancreatitis by modulating autophagy via ZG16

Chronic pancreatitis (CP) is a progressive fibro-inflammatory disorder with no effective anti-fibrotic treatment. Pancreatic stellate cells (PSCs) play a central role in pancreatic fibrosis by secreting excessive extracellular matrix (ECM) upon activation. Autophagy has been shown to promote PSC activation, yet its regulation remains unclear. This study focuses on ORM2, an acute-phase protein, and investigates whether it attenuates pancreatic fibrosis by modulating autophagy in PSCs.

A CP mouse model was induced by repeated caerulein injections. Pancreas-specific ORM2 knockout and overexpression were achieved via AAV-mediated strategies. Human PSCs (HPSCs) and primary mouse PSCs were treated with TGF-β1 to induce fibrotic activation in vitro. Autophagic flux was assessed using Western blot, transmission electron microscopy, and LC3B-RFP-GFP reporter assays. Protein-protein interactions were identified using the SPIDER technique and co-IP assay.

ORM2 was significantly downregulated in pancreatic tissue but upregulated in serum and liver during CP. Pancreas-specific ORM2 knockout exacerbated pancreatic fibrosis, while ORM2 overexpression attenuated fibrotic markers (α-SMA, COL1A1, FN) and tissue collagen deposition. ORM2 suppressed TGF-β1-induced fibrotic gene expression and inhibited autophagic flux by blocking autolysosome formation in vitro. SPIDER and co-IP analysis identified ZG16 as an ORM2-binding protein. ZG16 knockout abolished the anti-fibrotic effects of ORM2 in vitro and in vivo.

ORM2 alleviates pancreatic fibrosis in CP by binding to ZG16 and inhibiting autophagy-driven PSC activation. These findings identify ORM2 as a promising therapeutic agent for pancreatic fibrosis.