title: ADP-ribosylation factor 1 protein regulates trypsinogen activation via organellar trafficking of procathepsin B protein and autophagic maturation in acute pancreatitis.
abstract: Several studies have suggested that autophagy might play a deleterious role in acute pancreatitis via intra-acinar activation of digestive enzymes. The prototype for this phenomenon is cathepsin B-mediated trypsin generation. To determine the organellar basis of this process, we investigated the subcellular distribution of the cathepsin B precursor, procathepsin B. We found that procathepsin B is enriched in Golgi-containing microsomes, suggesting a role for the ADP-ribosylation (ARF)-dependent trafficking of cathepsin B. Indeed, caerulein treatment increased processing of procathepsin B, whereas a known ARF inhibitor brefeldin A (BFA) prevented this. Similar treatment did not affect processing of procathepsin L. BFA-mediated ARF1 inhibition resulted in reduced cathepsin B activity and consequently reduced trypsinogen activation. However, formation of light chain 3 (LC3-II) was not affected, suggesting that BFA did not prevent autophagy induction. Instead, sucrose density gradient centrifugation and electron microscopy showed that BFA arrested caerulein-induced autophagosomal maturation. Therefore, ARF1-dependent trafficking of procathepsin B and the maturation of autophagosomes results in cathepsin B-mediated trypsinogen activation induced by caerulein.
authors.affiliation: Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.
authors.forename: Lidiya
authors.initials: L
authors.lastname: Orlichenko
authors.forename: Donna B
authors.initials: DB
authors.lastname: Stolz
authors.forename: Pawan
authors.initials: P
authors.lastname: Noel
authors.forename: Jaideep
authors.initials: J
authors.lastname: Behari
authors.forename: Shiguang
authors.initials: S
authors.lastname: Liu
authors.forename: Vijay P
authors.initials: VP
authors.lastname: Singh
mesh_terms: D020823:ADP-Ribosylation Factor 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D001343:Autophagy / Q000187:drug effects*; D015153:Blotting, Western; D020126:Brefeldin A / Q000494:pharmacology; D002401:Cathepsin B / Q000378:metabolism*; D002108:Ceruletide / Q000494:pharmacology; D004792:Enzyme Precursors / Q000378:metabolism*; D006056:Golgi Apparatus / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D010195:Pancreatitis / Q000378:metabolism*; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D014362:Trypsinogen / Q000378:metabolism*
chemical_list: D004792:Enzyme Precursors; D020126:Brefeldin A; D002108:Ceruletide; D014362:Trypsinogen; C057832:procathepsin B; D002401:Cathepsin B; D020823:ADP-Ribosylation Factor 1