It has been known for some time that folic acid is vital to a healthy pregnancy, although researchers have been unsure exactly what the underlying physiological mechanisms of this requirement are. New work published in The FASEB Journal has shed light on this relationship, which has also highlighted the importance of a chemical modification to proteins called methylation. Scientists report that when a protein called Septin2 is not properly methylated, there is an increase in the risk of a disorder called neural tube defects or NTDs.
The Septin2 protein, encoded by the Septin2 gene, helps to regulate the structure of primary cilia. These types of cilia, which are different from motile cilia, act as a sort of antenna for the cell. They have been the focus of increasing research interest as scientists are finding cilia to have roles in a variety of signaling pathways in a huge variety of human cells; it seems most human cell types have a primary cilium and many important molecules can be found there at various times.
"Despite their impressive name, primary cilia are sometimes not accorded the high stature they should have in both embryonic development and in adult organs," explained Thoru Pederson, Ph.D., the Editor-in-Chief of The FASEB Journal. "The same might be said of the field of protein methylation. This work brings the two together in a most interesting case."
After genes that encode for proteins are translated, they are often subjected to chemical modifications. One such modification is methylation, in which methyl groups are added to the protein. That alteration can have a powerful impact on the protein’s function.
For this work, Richard H. Finnell, Ph.D., DABMGG, a researcher at the Department of Pediatrics, Dell Medical School, University of Texas at Austin and colleagues utilized mice that had been genetically engineered to inactivate a gene called slc19a1 under certain conditions. Slc19a1 is known to play a role in the transport of folic acid. The investigators were able to determine that when embryos don’t carry a functional slc19a1 gene, neural tubes defects occur. Further analysis revealed that there were concurrent problems with the methylation of the Septin2 protein.
Very early on in human development, the neural tube is supposed to close. A lack of folic acid can cause that to fail, resulting in serious and often untreatable birth defects. This happens so early in pregnancy, in the first month when many women may not even know they are pregnant, that food has been routinely supplemented with folic acid in an effort to prevent NTDs from happening. However, they remain one of the most common birth defects, with up to one in a thousand live births in the United States affected.
"NTDs are devastating birth defects that compromise multiple aspects of a child's development," commented Finnell. "Preventative methods, while remarkably effective, are not perfect. Efforts must be taken to understand leading developmental pathways that are amenable to modifications that offer hope for correcting the deficits secondary to failure of the neural tube to close properly during early embryogenesis,” Finnell concluded.
You can learn more about the association between neural tube defects and folic acid from the video above, by the Centers for Disease Control.