Cholesterol esters are detected by Raman microspectroscopy in HeLa cells

Abstract

The detection of trans-unsaturated lipids in single HeLa cells by Raman microspectroscopy was recently reported in this journal by Onogi et al. Based on our previously published Raman microspectroscopy data of individual macrophage foam cells, a detailed comparison between our spectra and spectrum reported by Onogi et al., and the reported literature spectrum of cholesterol oleate, we here provide evidence that cholesterol esters instead of trans-unsaturated lipids have been detected by Onogi et al.

Raman spectroscopy in cell biology and microbiology

“…[263] Endocytic vacuoles likely consist of CHL esters, as reported by a previous study of eukaryotic cells under environmental stress. [348] In conclusion, the present Raman analysis suggests that xylitol does not possess a veritable antibacterial action; it instead induces a high level of physiological stress in S. mutans bacteria that forces them to produce CHL-based vacuoles to free their endocytotical space. Such an action ultimately leads to bacteria starvation.…”

“…[ 263 ] Endocytic vacuoles likely consist of CHL esters, as reported by a previous study of eukaryotic cells under environmental stress. [ 348 ]…”

Analysis of Cholesterol Trafficking with Fluorescent Probes

“…Since the Raman signal is very weak, application of this technique to bioimaging is severely limited. Nevertheless, the method combined with confocal detection has been used to characterize cholesterol esters in HeLa cells and macrophage foam cells [117]. Moreover, Raman spectroscopy has been used as diagnostic tool to detect breast cancer, and combined Raman and fluorescence microscopy were applied to characterize atherosclerotic plaques [118, 119].…”

Recent advances in linear and nonlinear Raman spectroscopy. Part IV

“…Cholesterol esters were shown to be detected by Raman microspectroscopy in HeLa cells in a paper by van Manen and Otto 82. The differentiation of stem cells into specific cell types plays an essential role in the development of stem cell therapy, tissue engineering, and regenerative medicine.…”

“…[82] The differentiation of stem cells into specific cell types plays an essential role in the development of stem cell therapy, tissue engineering, and regenerative medicine. Chiang et al [83] use Raman microspectroscopy to monitor the development of hydroxyapatite [HA, Ca 5 (PO 4 ) 3 (OH)], which is associated with the differentiation of the human mesenchymal stem cells (hMSCs) into osteoblasts.…”