Role of Src in Antegrade Golgi Expansion and Autophagic Acinar Cell Death

Src family members are involved in diverse phenomena like cytoskeletal regulation (33) vesicular trafficking ( 7, 8 ) and inflammation (45, 46). Multiple pathogenic phenomena are simultaneously initiated during pancreatitis. We recently showed Src’s involvement in acinar cell actin reorganization and blebbing and that the Src inhibitor PP2 reduced pancreatic injury in rat caerulein pancreatitis.  However the role of specific Src family members in other deleterious phenomena operating in pancreatitis is unknown. Our preliminary studies suggest Src involvement in trypsinogen activation and acinar injury via Golgi fragmentation. This additional mechanism validates studying Src as a potential target for therapy in pancreatitis.

PRELIMINARY DATA:

Src is normally on the microsomal fraction in acinar cells and is activated by supraphysiologic caerulein. Dasatinib (10 micromolar), the Src inhibitor approved for humans prevented Src activation, trypsinogen activation, reduced LDH leakage induced by 100nM caerulein. Supraphysiologic caerulein also induced expansion and fragmentation of the Golgi, which was prevented by Dasatinib.  Caerulein increased the lipidated form of LC3 (LC3-II) and Dasatinib prevented relocation of the normally basal ER like staining of LC3 to the zymogen granule area. Pervanadate, the tyrosine phosphatase inhibitor, like supraphysiologic caerulein- activated Src, altered the Golgi, activated trypsinogen and induced LDH leakage from acinar cells. All of these were reduced by Dasatinib.

HYPOTHESIS:

Src mediated antegrade Golgi trafficking causes trypsinogen activation and autophagic acinar cell injury.

PROPOSED STUDIES:

Specific Aim-1: Identify organellar location of the Src family member involved in Golgi fragmentation
Specific Aim-2: Determine the mechanism of Src regulated Golgi fragmentation induced acinar injury.
Specific Aim-3: Determine the Role of Src in pancreatitis