Free fatty acids (FFAs) are classified into three categories based on the number of double bonds present in side chains: saturated (SFAs), monounsaturated (MUFAs), and polyunsaturated (PUFAs). Interestingly, FFAs are not only essential nutrients, but can also act as signaling molecules in several physiological processes. In this Research Topic, our main interest is the signaling activity of fatty acids when they bind to a specific family of G protein-coupled receptors, originally the members of this family were called: GPR40, GPR41, GPR43, GPR84 and GPR120. These receptors are now called Free Fatty Acid Receptors (FFARs), because different FFAs have been identified as their ligands. Apparently, the FFARs show specific affinities for different FFAs according to their chain length, so medium/long chain FFAs activate FFAR1 (GPR40) and FFAR4 (GPR120), whereas short chain FFAs activate FFAR2 (GPR43) and FFAR3 (GPR41). Additionally, there is another long-chain fatty acid receptor: CD36, although the main function is described as the uptake of long-chain FAs, it is also an important lipid sensor. CD36 (also known as FAT, by fatty acid translocase) belongs to the family of scavenger receptors.
Since the FFAs come from different sources, e.g.: medium/long chain FFAs are derived mainly from dietary triglycerides, and short chain FFAs are produced by intestinal microbial fermentation of dietary fiber, FFARs and CD36 are involved in various physiological scenarios, that include different physiological functions and cellular types. For example, FFAR1 is reported in the central nervous system, pancreatic ß-cells and bone marrow-derived cells. Moreover, FFAR1 and FFAR4 are expressed in intestinal L-cells, and FFAR4 is also expressed in hypothalamus, adipose tissue and taste buds. On the other hand, FFAR2 is reported in white adipocytes, intestinal epithelial cells and immune cells, and FFAR3 is reported in peripheral nerves, myeloid dendritic cells and the thymus. Considering all of these cell types, FFARs have also attracted attention as possible therapeutic targets for different disorders and diseases. On the other hand, the multifunctional protein CD36 plays a role in the gustatory detection of lipids, and it is known to bind to various ligands (e.g., thrombospondin-1, oxidized low-density lipoproteins and dietary FAs). Considering this current knowledge, this Research Topic aims to cover research on FFARs/CD36 and their cell signaling by considering a wide range of disciplines: membrane physiology, membrane biophysics, cellular signaling, cellular biochemistry, and cellular and molecular biology.
This Research Topic welcomes review papers and original research on the following themes but is not limited to them:
• Regulation of epithelial and endothelial cellular communication by free fatty acids and their receptors.
• Role of cellular signaling associated with free fatty acids and their receptors in the myoblast differentiation.
• Contribution of free fatty acids and their receptors in the functioning of the central nervous system.
• Participation of free fatty acid receptors in the regulation of mammalian intestinal microbial environment.
Free fatty acids (FFAs) are classified into three categories based on the number of double bonds present in side chains: saturated (SFAs), monounsaturated (MUFAs), and polyunsaturated (PUFAs). Interestingly, FFAs are not only essential nutrients, but can also act as signaling molecules in several physiological processes. In this Research Topic, our main interest is the signaling activity of fatty acids when they bind to a specific family of G protein-coupled receptors, originally the members of this family were called: GPR40, GPR41, GPR43, GPR84 and GPR120. These receptors are now called Free Fatty Acid Receptors (FFARs), because different FFAs have been identified as their ligands. Apparently, the FFARs show specific affinities for different FFAs according to their chain length, so medium/long chain FFAs activate FFAR1 (GPR40) and FFAR4 (GPR120), whereas short chain FFAs activate FFAR2 (GPR43) and FFAR3 (GPR41). Additionally, there is another long-chain fatty acid receptor: CD36, although the main function is described as the uptake of long-chain FAs, it is also an important lipid sensor. CD36 (also known as FAT, by fatty acid translocase) belongs to the family of scavenger receptors.
Since the FFAs come from different sources, e.g.: medium/long chain FFAs are derived mainly from dietary triglycerides, and short chain FFAs are produced by intestinal microbial fermentation of dietary fiber, FFARs and CD36 are involved in various physiological scenarios, that include different physiological functions and cellular types. For example, FFAR1 is reported in the central nervous system, pancreatic ß-cells and bone marrow-derived cells. Moreover, FFAR1 and FFAR4 are expressed in intestinal L-cells, and FFAR4 is also expressed in hypothalamus, adipose tissue and taste buds. On the other hand, FFAR2 is reported in white adipocytes, intestinal epithelial cells and immune cells, and FFAR3 is reported in peripheral nerves, myeloid dendritic cells and the thymus. Considering all of these cell types, FFARs have also attracted attention as possible therapeutic targets for different disorders and diseases. On the other hand, the multifunctional protein CD36 plays a role in the gustatory detection of lipids, and it is known to bind to various ligands (e.g., thrombospondin-1, oxidized low-density lipoproteins and dietary FAs). Considering this current knowledge, this Research Topic aims to cover research on FFARs/CD36 and their cell signaling by considering a wide range of disciplines: membrane physiology, membrane biophysics, cellular signaling, cellular biochemistry, and cellular and molecular biology.
This Research Topic welcomes review papers and original research on the following themes but is not limited to them:
• Regulation of epithelial and endothelial cellular communication by free fatty acids and their receptors.
• Role of cellular signaling associated with free fatty acids and their receptors in the myoblast differentiation.
• Contribution of free fatty acids and their receptors in the functioning of the central nervous system.
• Participation of free fatty acid receptors in the regulation of mammalian intestinal microbial environment.
