Fatty Acid-Binding Proteins and Substance Use Disorders: From Lipid Signaling to Therapeutic Targets

Fatty acid-binding proteins (FABPs) are a family of intracellular lipid chaperones that transport fatty acids and other hydrophobic molecules, playing essential roles in cellular lipid metabolism, signaling, and brain function. Within the central nervous system, FABP3, FABP5, and FABP7 facilitate the trafficking of long-chain polyunsaturated fatty acids and endocannabinoids, thereby modulating key regulatory pathways including the endocannabinoid system (ECS), peroxisome proliferator-activated receptor (PPAR) signaling, and dopaminergic neurotransmission. Peripherally, FABP1 and FABP4 contribute to hepatic drug metabolism, kidney excretion, and inflammatory processes in both tissues, with implications for the pharmacokinetics of substances of abuse. This narrative review synthesizes the current literature on FABPs and their involvement in substance use and addiction-related behaviors. Evidence from transgenic knockout models, pharmacological inhibition studies, and adeno-associated virus vector approaches demonstrates that manipulation of FABP subtypes can alter reward-related behaviors across multiple substances, including THC, ethanol, nicotine, and cocaine. Reduction or knockout of FABP7 alters THC metabolite levels in a sex-dependent manner. FABP3 shows involvement with dopamine receptor expression; however, interaction between FABP3 modulation and specific substances has sparsely been investigated. FABP5 has vastly diverging interactions with addictive behavior and appears to be substance dependent, as downregulation reduces cocaine self-administration, but knockout enhances nicotine conditioned place preference (CPP) and increases brain uptake of THC. Combined deletion of FABP5 and 7 additionally reduces cocaine CPP and reinstatement, while showing promising decreases in ethanol consumption paradigms. FABPs may be a potential therapeutic target for treating substance use disorders and underlying reward deficiency mechanisms underlying addiction and further research is required to elucidate specific mechanistic effects and eliminate potential adverse consequences of chronic FABP modulation.