HMGB1 modulation in pancreatic islets using a cell-permeable A-box fragment

Area of Science:

• Immunology
• Endocrinology
• Biotechnology

Background:

• Pancreatic islet transplantation is a potential cure for diabetes mellitus but faces challenges due to early graft loss.
• High-mobility group-box-1 (HMGB1) protein secreted by damaged islets contributes to immune elimination and graft failure.
• Modulating HMGB1 activity presents a therapeutic strategy to improve islet cell therapy success.

Purpose of the Study:

• To develop a cell-penetratable HMGB1 inhibitor for enhancing islet cell therapy.
• To evaluate the efficacy of TAT-labeled HMGB1 A-box-His6 (TAT-HMGB1A) in protecting transplanted islets.
• To assess the therapeutic potential of TAT-HMGB1A in a diabetes mellitus model.

Main Methods:

• Engineered TAT-HMGB1A protein for enhanced cellular uptake and HMGB1 binding.
• Assessed TAT-HMGB1A's effect on endogenous HMGB1 secretion and islet viability/function ex vivo.
• Implanted TAT-HMGB1A-treated islets into diabetic nude mice to evaluate therapeutic outcomes.
• Quantified the impact of TAT-HMGB1A on required islet mass and xenograft protection.

Main Results:

• TAT-HMGB1A effectively reduced endogenous HMGB1 secretion without compromising islet viability or function.
• Islet transplantation in diabetic mice cured diabetes, indicated by stable blood glucose levels.
• TAT-HMGB1A treatment decreased the necessary islet mass for diabetes cure and protected xenografts from immune rejection.

Conclusions:

• Cell-penetratable TAT-HMGB1A is a potent modulator of HMGB1 activity.
• TAT-HMGB1A significantly improves the success of ex vivo pancreatic islet cell therapy.
• This approach holds promise for enhancing islet graft survival and treating diabetes mellitus.