title: Differential expression and regulatory roles of FABP5 and FABP7 in oligodendrocyte lineage cells.
abstract: Fatty-acid-binding proteins (FABPs) are key intracellular molecules involved in the uptake, transportation and storage of fatty acids and in the mediation of signal transduction and gene transcription. However, little is known regarding their expression and function in the oligodendrocyte lineage. We evaluate the in vivo and in vitro expression of FABP5 and FABP7 in oligodendrocyte lineage cells in the cortex and corpus callosum of adult mice, mixed cortical culture and oligosphere culture by immunofluorescent counter-staining with major oligodendrocyte lineage markers. In all settings, FABP7 expression was detected in NG2(+)/PDGFRα(+) oligodendrocyte progenitor cells (OPCs) that did not express FABP5. FABP5 was detected in mature CC1(+)/MBP(+) oligodendrocytes that did not express FABP7. Analysis of cultured OPCs showed a significant decrease in the population of FABP7-knockout (KO) OPCs and their BrdU uptake compared with wild-type (WT) OPCs. Upon incubation of OPCs in oligodendrocyte differentiation medium, a significantly lower percentage of FABP7-KO OPCs differentiated into O4(+) oligodendrocytes. The percentage of mature MBP(+) oligodendrocytes relative to whole O4(+)/MBP(+) oligodendrocytes was significantly lower in FABP7-KO and FABP5-KO than in WT cell populations. The percentage of terminally mature oligodendrocytes with membrane sheet morphology was significantly lower in FABP5-KO compared with WT cell populations. Thus, FABP7 and FABP5 are differentially expressed in oligodendrocyte lineage cells and regulate their proliferation and/or differentiation. Our findings suggest the involvement of FABP7 and FABP5 in the pathophysiology of demyelinating disorders, neuropsychiatric disorder and glioma, conditions in which OPCs/oligodendrocytes play central roles.
authors.affiliation: Department of Organ Anatomy, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, 755-8505, Japan.
authors.forename: Kazem
authors.initials: K
authors.lastname: Sharifi
authors.forename: Majid
authors.initials: M
authors.lastname: Ebrahimi
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Kagawa
authors.forename: Ariful
authors.initials: A
authors.lastname: Islam
authors.forename: Tuerhong
authors.initials: T
authors.lastname: Tuerxun
authors.forename: Yuki
authors.initials: Y
authors.lastname: Yasumoto
authors.forename: Tomonori
authors.initials: T
authors.lastname: Hara
authors.forename: Yui
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Miyazaki
authors.forename: Nobuko
authors.initials: N
authors.lastname: Tokuda
authors.forename: Takeo
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Yuji
authors.initials: Y
authors.lastname: Owada
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D048708:Cell Growth Processes / Q000502:physiology; D019070:Cell Lineage; D002478:Cells, Cultured; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics; D009836:Oligodendroglia / Q000166:cytology / Q000378:metabolism*; D011247:Pregnancy; D015398:Signal Transduction
chemical_list: C082667:Fabp5 protein, mouse; C086936:Fabp7 protein, mouse; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins