Temperature conditions affect the lipid composition of giant plasma membrane vesicles obtained from cells.
About the authors
Olga (Olya) Vvedenskaya, Henri M Deda
Olga (Olya) Vvedenskaya
Sci. Communications Officer
Dr. Dr. Olya Vvedenskaya studied medicine, and further obtained her PhD in the field of molecular oncology. She loves to deliver scientific messages in a clear and accessible manner.
Henri M Deda
Head of Marketing
Henri Deda holds a degree in Molecular Bioengineering and Business Administration. He is motivated to provide inclusive, scientific answers.
• GPMVs from cells grown at different temperatures have different lipidome
• GPMVs from lower temperatures contain more PC
• GPMVs from higher temperatures contain more cholesterol
Olga (Olya) Vvedenskaya
Sci. Communications Officer
Dr. Dr. Olya Vvedenskaya studied medicine, and further obtained her PhD in the field of molecular oncology. She loves to deliver scientific messages in a clear and accessible manner.
Henri M Deda
Head of Marketing
Henri Deda holds a degree in Molecular Bioengineering and Business Administration. He is motivated to provide inclusive, scientific answers.
CELLS change their lipid content based on their environment. Both bacteria and higher organisms alter the composition and physical properties of their membranes when grown in different temperatures or depending on nutrient-availability. Cells adjust their plasma membrane composition to keep a certain level of lipid-mediated heterogeneity, which affects the arrangement and connections of cell surface proteins. When plasma membranes are isolated from live cells, they go through a miscibility transition below the growth temperature. These giant plasma membrane vesicles (GPMVs) are in a single liquid form at high temperatures, but at low temperatures, they separate into two different phases, liquid-ordered and liquid-disordered. These vesicles can transition between these two states in a reversible manner at the miscibility transition temperature (Tmix).
While the phase transition is not seen in membranes of intact cells, understanding the Tmix value is important as it can indicate the level of lipid heterogeneity in the original live cells from which the vesicles were obtained. Higher Tmix values in GPMVs predict a stronger level of membrane heterogeneity in live cells at a fixed growth temperature.
Experimental setup. Zebrafish cells were cultured in medium under various temperatures, including the optimal growth temperature of 28°C and experimental temperature of 20°C.
Burns et al., Biophysical Journal (2017), 10.1016/j.bpj.2017.04.052
The researchers found that the Tmix of GPMVs from the zebrafish cell line changes in response to the growth temperature. GPMVs from cells exhibit composition fluctuations and modulated domains, that cells adapt Tmix over approximately one cell cycle, and most importantly, cells have different membrane lipid compositions depending on their growth temperature.
In principle, these vesicles could include different lipids or different ratios of the same lipids, different proteins or protein expression levels, different concentrations of other membrane-soluble small molecules, or any combination of these variations. The researchers believed that the comprehensive lipid composition plays a significant role in the membrane’s biophysical properties. To test this hypothesis, they analyzed the lipid composition of GPMVs taken from cells grown at 20° or 28° C using a shotgun lipidomics technology platform.
Molar percent of lipid composition direction of changes depending on the growth temperature (20° and 28° C).A lipid classes, B total lipid unsaturation, C fatty acid chain unsaturation, and D fatty acid chain length; error bars show the mean +/- SE in four measurements.
Burns et al., Biophysical Journal (2017), 10.1016/j.bpj.2017.04.052
GPMVs from zebrafish contain a large variety of different lipid species, and the lipidomes of cells grown at 20° and 28° C largely overlap. However, there are some differences between them: cells grown at 20° C produce GPMVs with more phosphatidylcholine (PC) lipids and less cholesterol than GPMVs from cells grown at 28° C.
GPMVs from cells grown at 20° C contain more polyunsaturated fatty acids (PUFA) and fewer monounsaturated FA chains compared to GPMVs obtained from cells grown at 28° C. Interestingly, GPMVs from cells grown at 20° C have a broader distribution of fatty acid chain lengths although retaining the same average value.
Ten most abundant lipid species measured in GPMVs from cells grown depending on the growth temperature (20° and 28° C). Lipid species unique for each group are labeled in red text.
Burns et al., Biophysical Journal (2017), 10.1016/j.bpj.2017.04.052
Scientists also evaluated the individual most abundant lipid species that vary the most between GPMV isolated from the cells grown at different temperatures. The most abundant lipids in both experimental groups are cholesterol and PC lipids with either saturated or mono-unsaturated fatty acid chains. Additionally, some individual lipid species, particularly two PC species with PUFAs were found in GPMV from 20° C, and two phosphatidylethanolamines (PE) with PUFA lipids found in GPMV from 28° C.
Ten lipid species detected at higher abundance in GPMVs from cells grown depending on the growth temperature (20° and 28° C), the lipid species arranged according to the order of magnitude of increased abundance. Lipid species unique for each group are labeled in red text.
Burns et al., Biophysical Journal (2017), 10.1016/j.bpj.2017.04.052
In conclusion, the study showed that the lipid composition of GPMVs in zebrafish cells is influenced by growth temperature. Cells grown at lower temperatures produce GPMVs with lower cholesterol levels and higher levels of polyunsaturated lipids. These changes in lipid composition suggest that cells adjust their membrane composition to maintain a specific level of stability and to exploit the unique physical properties of supercritical systems for biological functions.
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