Figure 1. Drosophila model of diabetic cardiomyopathy.

(A) Ventral view of the heart tube. 3D structures are shown. The heart was stained for F-Actin with phalloidin (magenta) and for nuclei with DAPI; Cypher-GFP (green) labeled Z-lines of myofibers within cardiomyocytes. Arrowheads indicate the non-myocardial longitudinal muscle fibers, asterisks the alary muscles that support the heart, and arrows the abdominal muscles. (B) Dorsal view of the heart tube. Myocardial cells wrap in a circular fashion around the central cavity. Arrows show the ostia through which hemolymph from the abdomen enters into the heart tube and circulates. (C) HSD significantly reduced life span. w¹¹¹⁸ male flies were raised in 0.15 M or 1.0 M sucrose diet, food was changed every 2–3 days, and flies were counted every 10 days. HSD-fed flies displayed decreased median life span, 10 days shorter than flies fed an LSD. Mean ± SE are shown; n = 50 total flies in two separate experiments. The estimated median life span of HSD flies was also expressed as the percentage of LSD flies (*p = 7.61E-08 by log rank test). See also Figure S1. (D) Hemolymph glucose concentrations in 3-week-old, control and HSD-fed w¹¹¹⁸ adult flies. n≥6. (E) Hemolymph trehalose concentrations in 3-week-old, control and high sucrose-fed w¹¹¹⁸ adult flies. n≥6. (F) Bodies from w¹¹¹⁸ adults fed LSD or HSD for 3 weeks were treated with insulin (1 µM) or vehicle and visualized using antibodies against Drosophila PO₄-Akt or Syntaxin. n = 10. Bands from Western blot experiments were quantified, and PO₄-Akt was normalized to Syntaxin as a loading control. (G) Total triglycerides (TAG) were assayed enzymatically in 3-week-old control and high sugar-fed w¹¹¹⁸ adult flies, and normalized to weight. n≥12. Mean ± SE are shown. An unpaired, two-tailed t-test was used to derive p-values.