Molecule that transports DHA to the brain discovered
DHA in the brain: here is the molecule that transports it
It is called Mfsd2a and is the protein responsible for the uptake of DHA (docosahexaenoic acid) by the brain. Omega-3 is captured and translocated into the brain, where it is found in high concentrations, by the transport molecule that is found exclusively in the blood vessel cells of the central nervous system.
This is the discovery made by a team of researchers at the National University of Singapore, and published in the prestigious journal Nature.
DHA: the most important Omega-3 for the brain
DHA is an Omega-3 found primarily in fatty fish and oils of marine origin. It is essential for brain growth and for the development and maintenance of normal cognitive function, and is the fatty acid found in the highest concentration in the membranes of neurons. During embryonic developmental stages, maternal DHA is absorbed through the placenta as it passes from mother to fetus; in adults, on the other hand, it is derived primarily from foods consumed in the diet. DHA cannot be synthesized in nerve tissue and must be imported through the blood-brain barrier, which is the structure formed by endothelial cells tightly bound around the blood vessels of the brain. Such mechanisms of DHA uptake have remained misunderstood until now.
A protein transports DHA across the blood-brain barrier
Mfsd2a is a molecule belonging to the family of transporter proteins, which enable the movement of certain substances out of and into cells. To elucidate its role, Prof Silver and his team caused specific genetic mutations in laboratory mice, making them unable to produce Mfsd2a. Animals without the protein showed markedly reduced levels of DHA in brain tissue, and severe loss of neuronal cells in the hippocampus and cerebellum, as well as cognitive deficits and reduced brain growth (microcephaly). Unexpectedly, the study unveiled that Mfsd2a transports DHA in the form of lysophosphatidylcholine, i.e., phospholipids that are produced by the liver and circulate in high amounts in the blood. This represents an interesting finding because until now lysophosphatidylcholine was considered toxic to cells and its role in the 'body was unclear.
The main mechanism of uptake and transport of DHA
The results showed that the lack of the Mfsd2a protein had greatly reduced the passage of DHA, in the form of lysophosphatidylcholine, from plasma to the brain, demonstrating that Mfsd2a is necessary for Omega-3 absorption. The study made it possible for the first time to create a genetic model characterized by DHA deficiency, allowing the effects of this deficiency to be studied. The new information obtained could facilitate the development of technologies to incorporate DHA more effectively into food. The mechanism could then be exploited to maximize nutritional effects and increase growth and brain function. This is especially important for children born prematurely who did not receive enough Omega-3 during fetal development.
Source: Long N. Nguyen,Dongliang Ma,Guanghou Shui,Peiyan Wong,Amaury Cazenave-Gassiot, Xiaodong Zhang,Markus R. Wenk,Eyleen L. K. Goh & David L. Silver. "Mfsd2a is a transporter for the essential omega-3 fatty acid docosahexaenoic acid." Nature 509, 503-506 (May 22, 2014) doi:10.1038/nature13241
