The Role And The Mechanism Of Septin7 In Proliferation,Migration And Differentiation Of Oligodendrocyte Precursor Cells

Background:The highly dynamic cytoskeleton of oligodendrocyte lineage is a main driver for the motile behaviors and morphological changes that are interrelated with oligodendrocyte precursor cells(OPCs)process outgrowth,primary membrane wraps and myelin formation.Septins belongs to a family of GTP-binding proteins,which is recognized as a novel component of the cytoskeleton and is believed to function as a significant element in some dynamic,functionally active cellular processes.Septin7(Sept7)is unique out of 13 septins which has been found expressed in the myelin sheath in central nervous system(CNS)and involved in myelin formation and remyelination in our previous studies.However,the role of Sept7 in OPCs proliferation,migration and differentiation and that underlying mechanisms are still unknown.Objective:Investigate the effect of Sept7 in Oligodendrocyte precursor cell(OPC)proliferation,migration and differentiation and the underlying mechanisms.Method:In present study Immunofluorescence(IF),Q-PCR,and Western Blot(WB)were performed to analyze the expression of Sept7 in primary cultured OPC and OLN-93 cells,as well as relationship with microfilament and microtubules.After lentivirusmediated small interfering RNA(si RNA)targeting Sept7 administration,the changes of proliferation,migration and differentiation of primary cultured OPC and OLN-93 cells were detected by CCK8 assay,Scratch assay and morphological methods,respectively.And the expression of cytoskeleton protein and myelin associated proteins were measured by WB and IF.Results:The results showed that Sept7 expression was correlated with the differentiation of OPCs,and its distribution was spatially closely interacted with F-actin and ?-tubulin.After Sept7 was knocked down in OPCs,several morphological changes including loss of the polarity processes with short brush-like projections extending occurred accompanied with decreased the proliferation and increased migration.More critically,Sept7 knock down led to OPCs differentiate failure which lack of membranous processes and decreased expression of mature oligodendrocytes markers including MBP and CNP.Simultaneously,the spatial distribution and expression of F-actin and?-tubulin as well as acetylation level of ?-tubulin were changed.These results suggest that Sept7 plays an important role in proliferation,migration and differentiation of OPCs through interacting with microfilaments and microtubes,and Sept7 might have regulatory effect on myelin proteins expression.Conclusion:Sept7 plays an important role in proliferation,migration and differentiation of OPC through itself and regulation of other cytoskeletons.