(745.6) Liver Fatty Acid-Binding Protein (LFABP) Ablation Drives Hyperplastic Expansion of Subcutaneous Adipose Tissue in Male Mice Fed High-Fat Diet
Monday, April 4, 2022
10:15 AM – 12:15 PM
Location: Exhibit/Poster Hall A-B - Pennsylvania Convention Center
Poster Board Number: E361
Anastasia Diolintzi (Rutgers, Rutgers), YinXiu Zhou (Rutgers), Susan Fried (Icahn School of Medicine at Mount Sinai), Marianne Polunas (Rutgers), Labros Sidossis (Rutgers, Rutgers), Judith Storch (Rutgers, Rutgers)
Presenting Author Rutgers, Rutgers HIGHLAND PARK, New Jersey
Liver fatty acid-binding protein (LFABP) functions both in intracellular lipid trafficking in liver and small intestine, and in systemic energy homeostasis regulation. We found that despite the marked obesity of high fat-fed LFABP null (LFABP-/-) mice compared to their wild-type (WT) counterparts, they display a ‘metabolically healthy obese’ (MHO) phenotype characterized by normoglycemia and normoinsulinemia, increased spontaneous physical activity, and a resistance to high-fat diet (HFD)-induced decline in exercise capacity. They also display increased muscle fatty acid oxidation suggesting that adipose tissue lipolysis is enhanced. To gain insight into the effects of Lfabp ablation on the quality of adipose tissue, we determined the mass and cellularity of the inguinal (iWAT) and epididymal (eWAT) white adipose tissues.
LFABP-/- mice fed HFD for 12 weeks weighed 23.7% more (BW, g: 41.7 LFABP-/- vs 33.7 WT, p=0.006, n=5) and their fat pads tended to be heavier (iWAT, g: 1.1 LFABP-/- vs 0.8 WT, p=0.060, n=5; eWAT, g: 1.4 LFABP-/- vs 1.8 WT, p=0.065, n=5). Intriguingly, as shown in Figure 1, adipocyte size of iWAT adipocytes is smaller than that of the WT mice (44.6pL LFABP-/- vs 188.1pL WT per cell, p=0.009, n=5). Adipocyte number was substantially increased in the iWAT of LFABP-/- (23.6 LFABP-/- vs 4.6 WT x 106, p=0.001, n=5). In contrast, the eWAT adipocyte size in the LFABP-/- is comparable to WT (210pL LFABP-/- vs 268 pL WT per cell, p=0.293, n=5), and eWAT fat cell number was highly variable and trended higher in the LFABP-/- mice (9.8 LFABP-/- vs 4.7 WT x 106, p=0.059, n=5).Because LFABP is not expressed in adipose tissue, our data suggest that its ablation promotes interorgan signaling that may limit hypertrophy and drive hyperplasia in expansion of potentially metabolically beneficial subcutaneous iWAT. More studies are warranted to elucidate the marked differences in cell size and the apparent depot-dependent effects of LFABP-/- deficiency, as well as the mechanisms by which it modulates adipocyte growth and function.
R01 DK38389 (JS)
Figure 1. LFABP-/- iWAT adipocytes are markedly smaller than WT cells. H&E staining of iWAT from WT and LFABP-/- mice after 12 weeks of HF-feeding. Each image is from an individual mouse. Scale bars = 50 um.