Insights on aquaporins involvement in obesity-induced inflammation in pancreatic β-cells

Aquaporins (AQPs) are membrane channels that facilitate water and/or glycerol permeation through membranes. Among the 13 isoforms, AQP7 is tightly involved in insulin secretion while AQP12 was shown upregulated in pancreatitis. Using a loss-of-function/gain-of-function strategy in the pancreatic RIN-m5F cell line, we evaluated AQP7 and AQP12 expression and function as well as their involvement in cell proliferation, migration and adhesion in healthy conditions, and we investigated their contribution for obesity-induced inflammation in the endocrine pancreas. Our data confirm AQP7 as a functional water and glycerol channel in pancreatic beta-cells with importance for cell proliferation. Both AQP7 and AQP12 overexpressing cells show improved cell adhesion and migration. Their implication in inflammation was evaluated by assessing mRNA expression levels as well as of markers of inflammation in a pro-inflammatory condition (Streptozotocin STZ). Treated cells show upregulated AQP7 and AQP12 and proinflammatory markers (TNFα, IL-1β and IL6). However, AQP12 overexpression downregulates TNFα and IL-6, while AQP12-silencing dramatically upregulates TNFα and IL-6. These results indicate AQP12 may play a protective role in inflammation.