Monoenoic fatty acid requirement in V79 cells

Area of Science:

• Cell Biology
• Biochemistry
• Lipid Metabolism

Background:

• V79 cells exhibit dependency on exogenous lipids for growth.
• Lipid-deficient conditions halt V79 cell proliferation.
• cis-Octadecenoic acids can fulfill the lipid requirements for V79 cells.

Purpose of the Study:

• To investigate the lipid metabolism differences between V79 and V79-R cells.
• To identify the enzymatic basis for differential lipid requirements.
• To understand the role of monoenoic fatty acids in cell growth.

Main Methods:

• Cell culture with lipid-supplemented and lipid-free media.
• Analysis of phospholipid composition and fatty acid content.
• Measurement of [14C]acetic acid incorporation into fatty acids.
• Enzyme activity assays for stearoyl-CoA desaturase.

Main Results:

• V79 cell growth ceased in lipid-free medium, while V79-R cells could adapt.
• Phospholipid octadecenoic acid content increased slower in V79 cells.
• [14C]acetic acid incorporation into monoenoic fatty acids was reduced in V79 cells.
• V79 cells showed deficient stimulation of stearoyl-CoA desaturase activity.

Conclusions:

• V79 cells have a defect in synthesizing monoenoic fatty acids.
• Reduced stearoyl-CoA desaturase activity is responsible for the lipid requirement in V79 cells.
• This enzymatic deficiency explains the differential growth characteristics under lipid starvation.