Figure 6. Muscle-Pvf1 limits post-eclosion lipid recovery by suppressing lipid synthesis.

(A) Muscle-specific expression of pvf1 in freshly eclosed w¹¹¹⁸ males on days 0, 3 and 7 post eclosion. N = 4, 10 adult male abdominal cuticles were used per data point. One-way Anova followed by Dunnett multiple comparison test, ns denotes Not Significant with p=0.202, **** denotes p≤0.0001, error bars = SEM. (B) BODIPY staining of adipose tissue from 7-day-old control males (mus^ts = muscle-Gal4^Gal80ts) and males with muscle-specific over-expression of pvf1 (mus^ts>Pvf1) from Day 0 of eclosion. Panels on the right show identification of lipid droplets (LD) that are ≥ 5 μm in diameter using Cell Profiler. DAE = days after eclosion. (C) Quantification of number of adipose tissue cells that do not contain LDs that are ≥ 5 µm in diameter for control (mus^ts) flies and flies with muscle-specific over-expression of pvf1 (mus^ts>pvf1). N = 5/6 animals, Student t-test, **** denotes p≤0.0001, error bars = SEM. (D) Quantification of number of large (≥5 μm in diameter) LDs per cell in control (mus^ts) flies and flies with muscle-specific over-expression of pvf1 (mus^ts>pvf1). N = 5/6 animals, Student t-test, *** denotes p≤0.001, error bars = SEM. (E) Model of the role of muscle-derived Pvf1 in regulating systemic lipid content by signaling to the oenocytes of adult male flies.

Figure 6—figure supplement 1. Recovery of adipose tissue lipid stores involve formation and expansion of new lipid droplets, and, expansion of the adipose tissue cells.

BODIPY, DAPI and Phalloidin staining of adipose tissue preparations from w¹¹¹⁸ flies on day 0, day 3 and day 7 after eclosion. Topmost row shows images acquired with a 25x eyepiece. Bottom three rows show images acquired with a 40x eyepiece. Dotted white boxes show the regions that were re-imaged with the 40x lens. On day 0 post-eclosion, the adipose tissue is small with each cell having two nuclei that are positioned very close to each other. By day 3 and day 7, the adipose tissue cells become progressively larger and fill up with more lipid droplets per cell (both large and small).

Figure 6—figure supplement 2. Oenocyte-specific activation of lipid synthesis leads to increased lipid stores in the adipose tissue.

BODIPY staining showing neutral lipid accumulation in the adult male adipose tissue and oenocytes (dorsal abdominal cuticle) of control (oeno^ts>UAS) flies and flies with oenocyte-specific over-expression of fasn3 and fasn1 (oeno^ts>fasn3 and oeno^ts>fasn1). oeno^ts = oenocyte-Gal4^Gal80ts.