Caspase-3 gene silencing for inhibiting apoptosis in insulinoma cells and human islets

Area of Science:

• Regenerative Medicine
• Molecular Biology
• Immunology

Background:

• Islet transplantation is a potential treatment for type I diabetes.
• Graft failure is often caused by immune rejection, inflammation, and poor revascularization.
• Caspase-3 is critical in the apoptosis of transplanted islet cells.

Purpose of the Study:

• To investigate the efficacy of caspase-3 gene silencing in preventing cytokine-induced apoptosis of islet cells.
• To evaluate adenoviral vector-mediated delivery of short hairpin RNA (shRNA) targeting caspase-3 for enhanced islet survival and function.
• To assess the therapeutic potential of Adv-caspase-3-shRNA transduced islets in a mouse model of diabetes.

Main Methods:

• Chemically synthesized small interfering RNAs (siRNAs) were used to silence caspase-3 in insulinoma cells and human islets.
• Replication-deficient adenoviral (Adv) vectors encoding caspase-3 shRNA were constructed and optimized using U6 or H1 promoters.
• Adv-caspase-3-shRNA transduced islets were transplanted into streptozotocin-induced diabetic NOD-SCID mice, and graft function was monitored by blood glucose levels.

Main Results:

• siRNA transfection reduced caspase-3 transcripts and inhibited apoptosis in insulinoma cells.
• Adv-caspase-3-shRNA demonstrated efficient islet transduction, prolonged gene silencing (>5 days), and protection from cytokine-induced apoptosis.
• Transplantation of Adv-caspase-3-shRNA transduced islets restored normoglycemia in diabetic mice for over two weeks.

Conclusions:

• Adenoviral delivery of caspase-3 shRNA effectively protects transplanted islets from apoptosis.
• This approach shows significant potential for improving the success of islet transplantation in type I diabetes treatment.
• Restoration of normoglycemia confirms the functional recovery and long-term viability of the gene-modified islet grafts.