TY - JOUR
T1 - Effect of cholesterol on the lactosylceramide domains in phospholipid bilayers
AU - Hanashima, Shinya
AU - Ikeda, Ryuji
AU - Matsubara, Yuki
AU - Yasuda, Tomokazu
AU - Tsuchikawa, Hiroshi
AU - Slotte, J. Peter
AU - Murata, Michio
N1 - Funding Information:
We thank Prof. K. Iwabuchi, Juntendo University, for the discussions and suggestions. We are also grateful to Drs. Inazumi and Todokoro, Osaka University, for their technical assistance in solid-state NMR spectroscopy. This work was supported in part by the International Joint Research Promotion Program of Osaka University, a Grant-in-Aid for Scientific Research JP19K05713 (S.H.), JP16H06315 (M.M.), and JP19K22257 (M.M.) from the Japan Society for the Promotion of Science , Japan, and JST, CREST Grant Number JPMJCR18H2 (S.H.).
Publisher Copyright:
© 2022 Biophysical Society
PY - 2022/4/5
Y1 - 2022/4/5
N2 - Lactosylceramide (LacCer) in the plasma membranes of immune cells is an important lipid for signaling in innate immunity through the formation of LacCer-rich domains together with cholesterol (Cho). However, the properties of the LacCer domains formed in multicomponent membranes remain unclear. In this study, we examined the properties of the LacCer domains formed in Cho-containing 1-palmitoyl-2-oleoyl phosphatidylcholine (POPC) membranes by deuterium solid-state NMR and fluorescence lifetimes. The potent affinity of LacCer-LacCer (homophilic interaction) is known to induce a thermally stable gel phase in the unitary LacCer bilayer. In LacCer/Cho binary membranes, Cho gradually destabilized the LacCer gel phase to form the liquid-ordered phase by its potent order effect. In the LacCer/POPC binary systems without Cho, the 2H NMR spectra of 10′,10′-d2-LacCer and 18′,18′,18′-d3-LacCer probes revealed that LacCer was poorly miscible with POPC in the membranes and formed stable gel phases without being distributed in the liquid crystalline domain. The lamellar structure of the LacCer/POPC membrane was gradually disrupted at around 60°C, whereas the addition of Cho increased the thermal stability of the lamellarity. Furthermore, the area of the LacCer gel phase and its chain order were decreased in the LacCer/POPC/Cho ternary membranes, whereas the liquid-ordered domain, which was observed in the LacCer/Cho binary membrane, was not observed. Cho surrounding the LacCer gel domain liberated LacCer and facilitated forming the submicron to nano-scale small domains in the liquid crystalline domain of the LacCer/POPC/Cho membranes, as revealed by the fluorescence lifetimes of trans-parinaric acid and trans-parinaric acid-LacCer. Our findings on the membrane properties of the LacCer domains, particularly in the presence of Cho, would help elucidate the properties of the LacCer domains in biological membranes.
AB - Lactosylceramide (LacCer) in the plasma membranes of immune cells is an important lipid for signaling in innate immunity through the formation of LacCer-rich domains together with cholesterol (Cho). However, the properties of the LacCer domains formed in multicomponent membranes remain unclear. In this study, we examined the properties of the LacCer domains formed in Cho-containing 1-palmitoyl-2-oleoyl phosphatidylcholine (POPC) membranes by deuterium solid-state NMR and fluorescence lifetimes. The potent affinity of LacCer-LacCer (homophilic interaction) is known to induce a thermally stable gel phase in the unitary LacCer bilayer. In LacCer/Cho binary membranes, Cho gradually destabilized the LacCer gel phase to form the liquid-ordered phase by its potent order effect. In the LacCer/POPC binary systems without Cho, the 2H NMR spectra of 10′,10′-d2-LacCer and 18′,18′,18′-d3-LacCer probes revealed that LacCer was poorly miscible with POPC in the membranes and formed stable gel phases without being distributed in the liquid crystalline domain. The lamellar structure of the LacCer/POPC membrane was gradually disrupted at around 60°C, whereas the addition of Cho increased the thermal stability of the lamellarity. Furthermore, the area of the LacCer gel phase and its chain order were decreased in the LacCer/POPC/Cho ternary membranes, whereas the liquid-ordered domain, which was observed in the LacCer/Cho binary membrane, was not observed. Cho surrounding the LacCer gel domain liberated LacCer and facilitated forming the submicron to nano-scale small domains in the liquid crystalline domain of the LacCer/POPC/Cho membranes, as revealed by the fluorescence lifetimes of trans-parinaric acid and trans-parinaric acid-LacCer. Our findings on the membrane properties of the LacCer domains, particularly in the presence of Cho, would help elucidate the properties of the LacCer domains in biological membranes.
UR - http://www.scopus.com/inward/record.url?scp=85126387620&partnerID=8YFLogxK
U2 - 10.1016/j.bpj.2022.02.037
DO - 10.1016/j.bpj.2022.02.037
M3 - Article
C2 - 35218738
AN - SCOPUS:85126387620
SN - 0006-3495
VL - 121
SP - 1143
EP - 1155
JO - Biophysical Journal
JF - Biophysical Journal
IS - 7
ER -