Cellular differentiation and I-FABP protein expression modulate fatty acid uptake and diffusion

Area of Science:

• Cell Biology
• Biochemistry
• Molecular Biology

Background:

• Intestinal fatty acid binding protein (I-FABP) plays a role in cellular fatty acid metabolism.
• Embryonic stem cells (ES cells) possess unique metabolic properties that can change upon differentiation.

Purpose of the Study:

• To investigate the effect of intestinal fatty acid binding protein (I-FABP) expression on fatty acid uptake and intracellular diffusion in mouse embryonic stem (ES) cells.
• To determine how cellular differentiation influences these processes in ES cells, with or without I-FABP expression.

Main Methods:

• Utilized transfected pluripotent mouse ES cells engineered to stably express I-FABP.
• Quantified the uptake of a fluorescent fatty acid analog (NBD-stearic acid) using kinetic digital fluorescence imaging.
• Measured effective intracellular diffusion (Deff) via fluorescence recovery after photobleaching (FRAP).

Main Results:

• I-FABP expression in undifferentiated ES cells significantly increased NBD-stearic acid uptake rate (1.7-fold) and maximal uptake (1.6-fold), alongside enhanced diffusion (1.8-fold).
• Cellular differentiation of ES cells led to a decrease in I-FABP expression (up to 3-fold) and reduced NBD-stearic acid uptake and diffusion parameters (10-, 4.7-, and 2-fold, respectively).
• No significant differences in uptake or diffusion were observed between differentiated control ES cells and those differentiated with I-FABP expression.

Conclusions:

• I-FABP expression enhances fatty acid uptake and intracellular diffusion in undifferentiated ES cells.
• Cellular differentiation reverses the effects of I-FABP, decreasing both fatty acid uptake and diffusion.
• Differentiation and I-FABP expression have opposing effects on fatty acid transport dynamics in ES cells.