Pancreas-directed AAV8<i>-hSPINK1</i> gene therapy safely and effectively protects against pancreatitis in mice.

Abstract

Currently, there is no cure for chronic pancreatitis (CP). Germline loss-of-function variants in <i>SPINK1</i> (encoding trypsin inhibitor) are common in patients with CP and are associated with acute attacks and progression of the disease. This preclinical study was conducted to explore the potential of adeno-associated virus type 8 (AAV8)-mediated overexpression of human <i>SPINK1</i> (<i>hSPINK1</i>) for pancreatitis therapy in mice. A capsid-optimised AAV8-mediated <i>hSPINK1</i> expression vector (AAV8-<i>hSPINK1</i>) to target the pancreas was constructed. Mice were treated with AAV8-<i>hSPINK1</i> by intraperitoneal injection. Pancreatic transduction efficiency and safety of AAV8-<i>hSPINK1</i> were dynamically evaluated in infected mice. The effectiveness of AAV8-<i>hSPINK1</i> on pancreatitis prevention and treatment was studied in three mouse models (caerulein-induced pancreatitis, pancreatic duct ligation and <i>Spink1</i> c.194+2T>C mouse models). The constructed AAV8-<i>hSPINK1</i> vector specifically and safely targeted the pancreas, had low organ tropism for the heart, lungs, spleen, liver and kidneys and had a high transduction efficiency (the optimal expression dose was 2×10¹¹ vg/animal). The expression and efficacy of <i>hSPINK1</i> peaked at 4 weeks after injection and remained at significant level for up to at least 8 weeks. In all three mouse models, a single dose of AAV8<i>-hSPINK1</i> before disease onset significantly alleviated the severity of pancreatitis, reduced the progression of fibrosis, decreased the levels of apoptosis and autophagy in the pancreas and accelerated the pancreatitis recovery process. One-time injection of AAV8<i>-hSPINK1</i> safely targets the pancreas with high transduction efficiency and effectively ameliorates pancreatitis phenotypes in mice. This approach is promising for the prevention and treatment of CP.