1240-P: Changes in Protein Expression during Islet Regeneration in a Cystic Fibrosis-Related Diabetes (CFRD) Ferret Model

Abstract

Diabetes is a common complication among persons with cystic fibrosis (CF), affecting nearly 20% of adolescents and 50% of all adults with CF. The Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) knockout (KO) ferret is a well-characterized animal model of CF that exhibits distinct periods of dysglycemia and pancreatic remodeling that are similar to patterns observed in humans. After the first month of life (normoglycemia/Phase I), hyperglycemia develops during the second month of life (Phase II) with reduced islet mass, followed by a period of near normoglycemia (Phase III) during which the islet mass regenerates, followed by persistent hyperglycemia/CFRD at the 4th month of life (Phase IV). While dynamic changes in islet hormone mRNA levels have been described across these phases, changes in protein expression patterns have not been characterized. To this end, immunofluorescence was performed to characterize islet hormone expression patterns in age-matched CFTR KO and wild type (WT) ferrets, focusing on the regenerative Phase III. The relative intensity of immunofluorescent staining per islet area was calculated. Compared to WT ferrets, the relative staining intensity of insulin and glucagon increased (4.687 vs. 3.228, p<0.05 and 0.827 vs. 0.238, p<0.0001, respectively ), while the intensity of proinsulin decreased (1.061 vs. 1.455, p<0.05) in CF ferret sections. Our findings suggest increased efficiency of proinsulin processing and a potential compensatory upregulation of insulin expression during this phase with the surprising finding of increased glucagon expression. Additional studies are underway to further characterize changes in islet hormone expression across each of the four described phases as well as potential cellular dedifferentiation patterns. Disclosure H. M. Ismail: None. R. G. Mirmira: Advisory Panel; Self; Hibercell Inc., Sigilon Therapeutics, Inc., Veralox Therapeutics, Employee; Spouse/Partner; Beta Bionics, Inc. C. Evans-molina: Advisory Panel; Self; Provention Bio, Inc., Consultant; Self; Dompe, Other Relationship; Self; Bristol-Myers Squibb Company, Nimbus Pharmaceuticals, Pfizer Inc. R. N. Bone: None.