*Purpose: To study if Lacripep^TM-like peptide N-104 promotes beta-cell stabilization and islet transplantation outcomes. Background: Lacritin is a multifunctional tear protein with prosecretory, prosurvival and mitogenic properties. Islets are Lacritin responsive, and prominently express known elements of the Lacripep™ receptor complex and signaling pathways. N-104 peptide comprises the fifteen C-terminal amino acids of Lacritin.

*Methods: a) Human or mouse islets were cultured with 4µM of Lacripep^TM-like peptides N-94, N-104, N-104/C-6 or Tearpep3/N-104, or with negative control C95 or were left untreated in DMEM at 37oC for different periods of time ranging from 1 – 20 days. Islet viability was scored by propidium iodide – fluorescein diacetate staining, and function by Glucose Stimulated Insulin secretion (GSIS) assay. b) C57BL/6 islets were pretreated with 4 µM N-94, N-104, or C95, or saline for 24 hours followed by minimal islet mass transplantation into syngeneic diabetic recipients. Tail vein blood glucoses were measured daily.

*Results: For mouse islets, N-104 was ~45% more active than N-94 and 25% better than TearPep3/C-6 in GSIS assays. N-104 increased GSIS by about 5.5-fold, while N-94 or Tearpep3/N-104 increased GSIS by about 4-fold compared to untreated controls. Human islets cultured for 24hrs in the presence of N-104 also demonstrated a 2.7-fold GSIS increase compared with untreated controls. N-104/C-6 (in which six C-terminal amino acids have been removed) failed to enhance GSIS compared to untreated islets. The viability of human islets treated with N-104 was 95.6% at Day 6, and 84%, 66% and 58% following culture with N-94 C-95, and saline. Incubation of mouse islets with N-104 permanently returned syngeneically transplanted mice to normoglycemia with glucoses below 200mg/dL within 7 days post-transplant, with treatment efficacy continuing 55 days post-transplant. In comparison, N-94 restored blood glucose levels to normal after 9 days post-transplant. Blood glucose was <250mg/dL following treatment with C95 at Day12 post-transplant. Average blood glucoses measured between Days 22 to 43 was 151±20.7mg/dL for N-104 group and 142.9±17.6mg/dL for N-94 group compared to 275±34.8mg/dL for the C95 group.

*Conclusions: Islet viability, glucose stimulated insulin secretion, and transplantation outcomes indicate that N-104 is the most viable candidate for clinical translation as an interventional agent to promote islet transplantation outcomes.

« Back to 2021 American Transplant Congress