Potential role of CXCL10 in the induction of cell injury and mitochondrial dysfunction

Abstract

Chemokines have been known to play a critical role in pathogenesis of chronic pancreatitis and acinar cell death. However, the role played by one of the CXC chemokines: CXCL10 in regulation of acinar cell death has remained unexplored. Hence, this study was designed to assess the role of CXCL10 promoting apoptosis in ex vivo cultured acinar cells. Primary human pancreatic acinar cell cultures were established and exposed to varying doses of CXCL10 for different time intervals. Apoptotic induction was evaluated by both qualitative as well as quantitative analyses. Various mediators of apoptosis were also studied by Western blotting, membrane potential (Psim) and ATP depletion in acinar cells. Analysis of apoptosis via DNA ladder and cell death detection - ELISA demonstrated that CXCL10 induced 3.9-fold apoptosis when administrated at an optimal dose of 0.1 mug of recombinant CXCL10 for 8 h. Quantitative analysis using FACS and dual staining by PI-annexin showed increased apoptosis (48.98 and 53.78% respectively). The involvement of upstream apoptotic regulators like pJNK, p38 and Bax was established on the basis of their increased expression of CXCL10. The change of Psim by 50% was observed in the presence of CXCL10 in treated acinar cells along with enhanced expression of Cytochrome C, apaf-1 and caspase 9/3 activation. In addition, ATP depletion was also noticed in CXCL10 stimulated acinar cells. CXCL10 induces cell death in human cultured pancreatic cells leading to apoptosis and DNA fragmentation via CXCR3 signalling. These signalling mechanisms may play an important role in parenchymal cell loss and injury in pancreatitis.