Table 1.
Lipid compositions of healthy and diseased bilayers calculated as mole % of lipid in the extracellular (EXT) and cytoplasmic (CYT) faces of myelin membranes
| Lipid type (i) | Healthy |
EAE |
||||||
|---|---|---|---|---|---|---|---|---|
| EXT, XiEXT | CYT, XiCYT | Bilayer, XiTOT | CYT, xiCYT | EXT, XiEXT | CYT, XiCYT | Bilayer, XTOT | CYT, xiCYT* | |
| Cholesterol (CHOL) | 22.4 | 10.6 | 32.9 | 31.6 | 25.8 | 12.1 | 37.9 | 37.4 |
| Phosphatidylserine (PS−) | 0.7 | 2.4 | 3.1 | 7.0 | 4.7 | 2.4 | 7.1 | 7.4 |
| Hydroxylated cerebrosides (HCER) | 13.9 | 0 | 13.9 | 0 | 14.7 | 0 | 14.7 | 0 |
| Nonhydroxylated cerebrosides (NCER) | 2.3 | 0 | 2.3 | 0 | 2.4 | 0 | 2.4 | 0 |
| Cerebroside sulfatide (SCER−) | 6.4 | 0 | 6.4 | 0 | 3.8 | 0 | 3.8 | 0 |
| Sphingomyelin (SM ±) | 2.8 | 2.1 | 4.9 | 6.2 | 0.9 | 0.7 | 1.6 | 2.2 |
| Phosphatidylcholine (PC ±) | 12.1 | 8.7 | 20.8 | 25.9 | 8.9 | 6.5 | 15.4 | 20.1 |
| Phosphatidylethanolamine (PE ±) | 6.0 | 9.7 | 15.7 | 29.0 | 6.5 | 10.6 | 17.1 | 32.9 |
| Total mole %, ΣXi and Σxi | 66.5 | 33.5 | 100 | 100 | 67.8 | 32.2 | 100 | 100 |
XiTOT is the total mole fraction (percent of lipid of type i, so that ΣiXiTOT = 100%. XiEXT and XiCYT are the total mole fractions of lipid of type i in the extracellular and cytoplasmic faces, so that XiTOT = XiEXT + XiCYT, and ΣiXiTOT = ΣiXiEXT + ΣiXiCYT = 100%. xiCYT are the mole fractions of lipid of type i in the cytoplasmic faces only, so that ΣixiCYT = 100%. The xi and Xi values are related by xiCYT = 100XiCYT /ΣiXiCYT. We may note that the total mole fraction of lipids in the extracellular faces ΣiXiEXT is typically twice that for the cytoplasmic lipids ΣiXiCYT (see bottom row). The “missing” volume is likely taken up by the MBP in the cytoplasmic spaces. Myelin membranes are from marmoset white matter (10).
*These compositions were used in the experiments.