Dietary fatty acids modulate lipolytic enzymes via distinct allosteric and exosite mechanisms: An integrated in vivo and in silico study linking Cafeteria diet-induced obesity to altered lipid metabolism

The escalating prevalence of obesity necessitates a deeper molecular understanding of how high-fat diets disrupt lipid metabolism. This study aimed to elucidate the potential mechanisms by which dietary fatty acids (FAs) modulate the key lipolytic enzymes, lipoprotein lipase (LPL) and hormone-sensitive lipase (HSL). An integrated in vivo and in silico approach was employed: Wistar rats were fed a standard or hypercaloric cafeteria diet for 8 weeks, after which physiological parameters, tissue lipid content, and enzyme activities were assessed. Molecular docking was used to characterize interactions between diet-specific FAs and enzyme crystal structures. The cafeteria diet induced significant obesity (+32.8% body weight, p < 0.001), adipose expansion (+137%, p < 0.001), pro-atherogenic dyslipidemia (+50.5% plasma triglycerides, p < 0.001), and hepatic steatosis (+56% triglycerides, p < 0.001). Paradoxically, both LPL and HSL activities were significantly upregulated in adipose tissue (+28.6%, p < 0.01 and + 89.7%, p < 0.001, respectively). Docking simulations suggested a potential mechanistic segregation: saturated FAs from the cafeteria diet were predicted to bind a putative allosteric site on LPL chain B, while polyunsaturated FAs from standard chow preferentially docked to the canonical active site on chain A. For HSL, all dietary FAs were predicted to bind with high affinity to an exosite on chain A, distinct from the inhibitor site. Together, these findings propose that dietary FAs may act as allosteric and exosite modulators of lipolytic enzymes, providing a candidate molecular link between diet composition and lipid dysregulation in obesity. This repositioning of dietary lipids as potential regulatory molecules opens new avenues for precision nutrition. However, given the multifaceted compositional differences between the cafeteria and control diets, the observed in vivo effects cannot be attributed solely to saturated versus polyunsaturated fatty acid differences, and these findings require further validation using purified diets and targeted structural approaches.