On the surface of many cells are specialized proteins that act like docking stations for molecular signals. One such protein is G protein-coupled receptor 120 (GPR120), also known as Free Fatty Acid Receptor 4 (FFAR4). This receptor belongs to a large family of proteins that sense molecules outside the cell and initiate an internal response. The primary role of GPR120 is to detect the presence of certain long-chain fatty acids that circulate in the body.
GPR120 is found in various tissues, including fat cells, immune cells, and the cells lining the gut. Its discovery and ongoing study have highlighted its connection to overall health, as it helps the body monitor and respond to dietary components.
How GPR120 is Activated
The activation of GPR120 is a specific process, much like a key fitting into a lock. The “keys” in this scenario are long-chain fatty acids, particularly the omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). When these fatty acids are present, they bind to the GPR120 receptor, causing a change in the receptor’s shape that triggers signals inside the cell.
These specific omega-3 fatty acids are not produced efficiently by the human body and are primarily obtained through diet. Fatty fish are among the richest sources of both DHA and EPA. Varieties include:
- Salmon
- Mackerel
- Herring
- Sardines
Consuming these types of fish provides the necessary molecules to activate GPR120 receptors.
For individuals who do not consume fish, other sources are available to ensure an adequate intake of these fatty acids. Fish oil supplements are a common and direct way to obtain concentrated doses of EPA and DHA. A plant-based alternative is algal oil, which is derived from marine algae, the original source of omega-3s for fish. Including these sources in one’s diet provides the foundational elements for GPR120 to perform its functions.
Role in Metabolism and Weight Regulation
Once activated, GPR120 plays a part in regulating the body’s energy balance and metabolic health. On fat cells, or adipocytes, GPR120 activation helps them become more responsive to insulin. This improved insulin sensitivity allows for more efficient uptake of glucose from the bloodstream, which helps maintain stable blood sugar levels.
The receptor also functions within the gastrointestinal system, where it influences appetite and nutrient processing. GPR120 is expressed on endocrine cells in the gut lining that release hormones in response to food. Activation of GPR120 in these cells stimulates the secretion of hormones like glucagon-like peptide-1 (GLP-1). GLP-1 slows down digestion, promotes a feeling of fullness, and enhances the release of insulin from the pancreas.
Beyond its effects on insulin and gut hormones, GPR120 influences how the body’s fat tissue develops and functions. The receptor promotes the healthy differentiation and storage capacity of adipocytes. This encourages the proper management of lipids, directing them toward safe storage in fat tissue rather than accumulating in other organs like the liver. This regulation of fat tissue contributes to a healthier metabolic profile.
Anti-Inflammatory Properties
Separate from its metabolic duties, GPR120 activation has notable anti-inflammatory effects. This function is linked to the receptor’s presence on immune cells, especially macrophages. Macrophages are involved in the body’s inflammatory response, a process that can become harmful when it is chronically active. Persistent, low-grade inflammation is associated with a number of long-term health conditions.
The activation of GPR120 on macrophages by omega-3 fatty acids initiates an internal signaling pathway that dampens inflammation. This process involves a protein called beta-arrestin-2. When GPR120 is activated, it recruits beta-arrestin-2, which in turn interacts with other proteins to block the pathways that lead to the production of pro-inflammatory substances. This mechanism helps to resolve the inflammatory response.
This molecular action provides a basis for the well-documented anti-inflammatory benefits of omega-3s. By signaling through GPR120, fatty acids like DHA and EPA can directly influence immune cell behavior and reduce inflammatory activity. This effect is distinct from the receptor’s role in metabolism, showcasing the multifaceted nature of GPR120.
Therapeutic Potential and Future Research
The diverse functions of GPR120 in metabolism and inflammation have made it a subject of interest for pharmaceutical companies. Because of its role in improving insulin sensitivity and reducing inflammation, the receptor is a promising target for developing new medicines. Researchers are exploring drugs, known as agonists, designed to activate GPR120 and replicate the beneficial effects of omega-3 fatty acids.
These potential therapies could offer new treatment avenues for complex conditions like metabolic syndrome and type 2 diabetes, where both insulin resistance and chronic inflammation are present. By targeting GPR120, a single drug could address multiple aspects of these diseases simultaneously. The anti-inflammatory properties of GPR120 activation also suggest its potential use in treating chronic inflammatory disorders.
The development of GPR120 agonists is an active area of investigation. Research is ongoing to create compounds that are both effective and safe for human use. Future studies will continue to refine these potential drugs and clarify the intricate mechanisms through which GPR120 signaling impacts health and disease.