Oleic acid differentially affects de novo lipogenesis in adipocytes and hepatocytes

Figures

• 

  Figure 1.. Schematic of experiments and data collection. (A) Isotope labelling of de novo lipogenesis and fatty-acid scavenging pathways. (B) Live cell data collection by OPTIR. Cells grown on a calcium fluoride cover slip are mounted in PBS using a spacer. (C) Multispectral imaging at single frequencies of interest.

• 

  Figure 2.. Live cell characterization of the cell lines (A) Huh-7 and (B) differentiated 3T3-L1 after feeding with 2H oleic acid and 13C glucose. Scale bars are 20 μm. (C) Full IR spectra of a point within a Huh-7 cell LD 48 hours after feeding 2H OA. (D) 2H-C from the 2H oleic acid (structure in inset) which has been esterified in LDs. 2214 cm−1 is assigned to 2H-C stretching. (E) 13C=O stretch of triglycerides at 1703 cm−1 where the 13C comes from metabolized 13C glucose (structure in inset). Pictured alongside the unlabelled 12C=O band at 1744 cm−1.

• 

  Figure 3.. Visualization of rates of de novo lipogenesis in live Huh-7 cells fed with both 2H OA and 13C glucose. (A) Brightfield images of live cells. (B) 2H OA ratio images of 2H lipid to the 12C lipid band, after correction. (C) 13C glucose ratio images of the 13C lipid band to the 12C lipid band, after correction. (D) Representative spectra of the live Huh-7 cell at the 48-hour time point both inside a LD (pink) and outside the droplet (blue) (E) Average ratios of 2H lipid band (grey) and 13C lipid band (red) to 12C lipid band across many cells (N = 14). Scale bars are 10 µm.

• 

  Figure 4.. Effect of OA feeding on rates of de novo lipogenesis. Ratio of 13C lipid to 12C lipid in live (A) Huh-7 and (B) 3T3-L1 cells fed with both 2H oleic acid and 13C glucose (red) or BSA vehicle and 13C glucose (purple) at their respective time points. N = 8–16 cells per time point * p-value < 0.05 ** p-value < 0.005 ***p-value < 0.0005 N.S. p-value > 0.05