The Stathmin 1-lineage Contributes to Acinar Regeneration but Not to Neoplasia Upon Oncogenic Kras Expression.

BACKGROUND & AIMS: The exocrine pancreas has a limited regenerative capacity, but to what extent all acinar cells are involved in this process is unclear. Nevertheless, the heterogenous nature of acinar cells suggests that cells exhibiting higher plasticity might play a more prominent role in acinar regeneration. In that regard, stathmin 1 (Stmn1)-expressing acinar cells have been identified as potential facultative progenitor-like cells in the adult pancreas. Here, we studied Stmn1-progeny under physiological conditions, during regeneration, and in the context of Kras(G12D) expression. METHODS: We followed the fate of Stmn1-progenies both under baseline conditions, following caerulein-induced acute or chronic pancreatitis, pancreatic duct ligation, and in the context of Kras(G12D) expression. RESULTS: The Stmn1-lineage contributes to baseline acinar cell turnover under physiological conditions. Furthermore, these cells rapidly proliferate and repopulate the acinar compartment in response to acute injury in an acinar-to-ductal metaplasia (ADM)-independent manner. Moreover, acinar regeneration during chronic pancreatitis progression is in conjunction with a decline in the proliferative capacity of the Stmn1-lineage. Interestingly, newly generated acinar cells display increased susceptibility to additional injury during recurrent acute pancreatitis. Finally, given their inability to form ADMs, the Stmn1-lineage fails to form pancreatic intraepithelial neoplasia upon oncogenic Kras expression. CONCLUSIONS: Our findings establish the Stmn1-lineage as a pivotal subpopulation for acinar regeneration. The ability of these cells to restore acinar tissue in an ADM-independent manner distinguishes them as a critical regenerative population. This study presents a new paradigm for acinar regeneration and repair in the context of pancreatitis and neoplasia.