Discussion
Lipid microdomains are postulated to play a key role in signal transduction within a cell (Calder & Yaqoob, 2006). Literature suggests that these lipid microdomains are located in fractions 1-4 while the bulk lipids are located in fractions 5-10 (Pike, 2003). Fractions are determined by the protein’s density or molecular weight. Past researchers determined that lipid microdomains weigh much less and float on the plasma membrane.
Within the control, the proteins caveolin and flotillin were determined to be more prevalent within fractions 1-4 and not as prevalent within fractions 5-10. However the addition of βMCD, which is known to remove cholesterol from the plasma membrane and disperse lipid microdomains, caused a shift in caveolin and flotillin from fractions 1-4 to fractions 5-10. This suggests that βMCD is dispersing a part of the plasma membrane’s lipid microdomains into the bulk lipids. This same result was demonstrated with the addition of fish oil containing omega-3 fatty acids.
When 0.03% fish oil was added, a shift occurred such that caveolin and flotillin were no longer as noticeable in fractions 1-4. It is postulated that the omega-3 fatty acids found in fish oil caused the cholesterol, sphingolipids, and proteins within the lipid microdomains to disperse so that there was space for the fatty acids. Thus the lipid microdomains could no longer maintain an
ordered structure as seen in controls. This might have affected cell signaling; however, there is much controversy surrounding this concept as lipid microdomains are still not widely accepted by the research community as a part of the cell or responsible for cellular transduction (Calder & Yaqoob, 2006).
This controversy arises from the fact that individual lipid microdomains cannot yet be visualized through scientific means and their purpose and function remain unclear. It is believed that lipid microdomains are no bigger than 5 – 500 nm in length (Pike, 2003). A regular luteal cell might be as large as or larger than 200 µm (Calder & Yaqoob, 2006). However, multiple experiments over the years have suggested that lipid microdomains are the part of the cell that is responsible for cell signaling among other functions (Pike, 2008).
With the dispersion of plasma membranes and possibly lipid microdomains, researchers have been able to inhibit known cellular signaling pathways in many different cell lines (Calder& Yaqoob, 2006). This experiment explored inhibiting the apoptotic PGF2α cell signaling pathway. This inhibition of PGF2α pathway might be suggested by our findings and the result being a shift of the known proteins associated with lipid microdomains. Thus, allowing the CL and the bovine embryo more time to establish and maintain a healthy pregnancy to full term. Omega-3 fatty acids in fish oils might be a novel and inexpensive approach to improve bovine maternal recognition of pregnancy from our conclusions and warrant further investigation.
In conclusion, a shift in the proteins caveolin and flotillin from fractions 1-4 to fractions 5-10 was seen and this was postulated as due to the omega-3 fatty acids incorporating into the lipid microdomains and dispersing the other associated components. Thusly, our hypothesis was supported. Other researchers have demonstrated the same effect with different cell lines (White, et al.,2011). Due to these results, it is reasonable to continue further experiments with fish oil containing omega-3 fatty acids and lipid microdomains on the bovine CL and explore improving bovine reproduction in order to reduce cost to the U.S. beef and dairy industries and to the consumer.
Within the control, the proteins caveolin and flotillin were determined to be more prevalent within fractions 1-4 and not as prevalent within fractions 5-10. However the addition of βMCD, which is known to remove cholesterol from the plasma membrane and disperse lipid microdomains, caused a shift in caveolin and flotillin from fractions 1-4 to fractions 5-10. This suggests that βMCD is dispersing a part of the plasma membrane’s lipid microdomains into the bulk lipids. This same result was demonstrated with the addition of fish oil containing omega-3 fatty acids.
When 0.03% fish oil was added, a shift occurred such that caveolin and flotillin were no longer as noticeable in fractions 1-4. It is postulated that the omega-3 fatty acids found in fish oil caused the cholesterol, sphingolipids, and proteins within the lipid microdomains to disperse so that there was space for the fatty acids. Thus the lipid microdomains could no longer maintain an
ordered structure as seen in controls. This might have affected cell signaling; however, there is much controversy surrounding this concept as lipid microdomains are still not widely accepted by the research community as a part of the cell or responsible for cellular transduction (Calder & Yaqoob, 2006).
This controversy arises from the fact that individual lipid microdomains cannot yet be visualized through scientific means and their purpose and function remain unclear. It is believed that lipid microdomains are no bigger than 5 – 500 nm in length (Pike, 2003). A regular luteal cell might be as large as or larger than 200 µm (Calder & Yaqoob, 2006). However, multiple experiments over the years have suggested that lipid microdomains are the part of the cell that is responsible for cell signaling among other functions (Pike, 2008).
With the dispersion of plasma membranes and possibly lipid microdomains, researchers have been able to inhibit known cellular signaling pathways in many different cell lines (Calder& Yaqoob, 2006). This experiment explored inhibiting the apoptotic PGF2α cell signaling pathway. This inhibition of PGF2α pathway might be suggested by our findings and the result being a shift of the known proteins associated with lipid microdomains. Thus, allowing the CL and the bovine embryo more time to establish and maintain a healthy pregnancy to full term. Omega-3 fatty acids in fish oils might be a novel and inexpensive approach to improve bovine maternal recognition of pregnancy from our conclusions and warrant further investigation.
In conclusion, a shift in the proteins caveolin and flotillin from fractions 1-4 to fractions 5-10 was seen and this was postulated as due to the omega-3 fatty acids incorporating into the lipid microdomains and dispersing the other associated components. Thusly, our hypothesis was supported. Other researchers have demonstrated the same effect with different cell lines (White, et al.,2011). Due to these results, it is reasonable to continue further experiments with fish oil containing omega-3 fatty acids and lipid microdomains on the bovine CL and explore improving bovine reproduction in order to reduce cost to the U.S. beef and dairy industries and to the consumer.