Ablation of Mea6/cTAGE5 in oligodendrocytes significantly impairs white matter structure and lipid content

Lipid-rich myelin is a special structure formed by oligodendrocytes wrapping neuronal axons.Abnormal myelin sheath is associated with many neurological diseases.Meningioma-expressed antigen 6(Mea6)/cutaneous T cell lymphoma-associated antigen 5C(cTAGE5C)plays an important role in vesicle trafficking from the endoplasmic reticulum(ER)to Golgi,and conditional knockout(cKO)of Mea6 in the brain significantly affects neural development and brain function.However,whether the impaired brain function involves the development of oligodendrocytes and white matter beyond neurons remains unclear.In this study,by using different models of diffusion magnetic resonance imaging,we showed that cKO of Mea6 in oligodendrocytes leads to significant impairment of the gross and microstructure of the white matter,as well as a significant decrease of cholesterol and triglycerides in brains.Our lipidomic analysis of purified myelin sheath for the first time showed that Mea6 elimination in oligodendrocytes significantly altered the lipid composition in myelin lipidome,especially the proportion of very long chain fatty acids(VLCFAs).In particular,the levels of most VLCFA-containing phosphatidylcholines were substantially lower in the myelin sheath of the cKO mice.The reduction of VLCFAs is likely due to the downregulated expression of elongation of very long chain fatty acids(ELOVLs).Our study of an animal model with white matter malformation and the comprehensive lipid profiling would provide clues for future studies of the formation of myelin sheath,myelin lipids,and the pathogenesis of white matter diseases.

Molecular mechanisms underlying cTAGE5/MEA6-mediated cargo transport and biological functions

Coat protein complex Ⅱ(COPⅡ)-coated vesicles are responsible for transporting the cargoes from the endoplasmic reticulum(ER) to different destinations. c TAGE5/MEA6 is essential for the development and function of different organs. It regulates the assembly of COPⅡ carrier and cargo trafficking through direct or indirect interaction with COPII components. c TAGE5/MEA6 mainly coordinates with another scaffold protein, TANGO1, to play essential roles in the trafficking and secretion of both large and small cargoes in multiple organs. In this viewpoint, we would like to discuss the molecular mechanisms underlying c TAGE5/MEA6-mediated cargo transport and biological functions.

一种检测2'-甲基-6'-乙基-2-氯乙酰苯胺水解酶活性的方法

建立了一种快速测定Delftia acidovorans T3-6菌株2'-甲基-6'-乙基-2-氯乙酰苯胺(CMEPA)水解酶活性的方法。在20 mmol·L^(-1)Tris-HCl(p H值为7.0)缓冲液中,10~50μmol·L^(-1)的CMEPA水解产物2-甲基-6-乙基苯胺(MEA)在铁氰化钾催化下与4-氨基安替比林反应生成紫红色物质,该物质在535 nm处的吸光度(y)与MEA浓度(x)呈正相关(y=0.014 6x-0.005 4,R2=0.998 8)。底物CMEPA、十二烷基硫酸钠(SDS)、甲醇等有机试剂以及1 mmol·L^(-1)金属离子对显色反应无显著影响,温度和p H值对显色反应影响显著。4-氨基安替比林显色法对菌株T3-6粗酶液酶活性的测定结果与二氯甲烷萃取-紫外分光光度法无显著差异。该方法也适用于其他苯胺苯酚类衍生物的测定。