ABSTRACT
Enhancing remyelination after injury is of utmost importance for optimizing the recovery of nerve function. While the formation of myelin by Schwann cells (SCs) is critical for the function of the peripheral nervous system, the temporal dynamics and regulatory mechanisms that control the progress of the SC lineage through myelination require further elucidation. Here, using in vitro co-culture models, gene expression profiling of laser capture-microdissected SCs at various stages of myelination, and multilevel bioinformatic analysis, we demonstrated that SCs exhibit three distinct transcriptional characteristics during myelination: the immature, promyelinating, and myelinating states. We showed that suppressor interacting 3a (Sin3A) and 16 other transcription factors and chromatin regulators play important roles in the progress of myelination. Sin3A knockdown in the sciatic nerve or specifically in SCs reduced or delayed the myelination of regenerating axons in a rat crushed sciatic nerve model, while overexpression of Sin3A greatly promoted the remyelination of axons. Further, in vitro experiments revealed that Sin3A silencing inhibited SC migration and differentiation at the promyelination stage and promoted SC proliferation at the immature stage. In addition, SC differentiation and maturation may be regulated by the Sin3A/histone deacetylase2 (HDAC2) complex functionally cooperating with Sox10, as demonstrated by rescue assays. Together, these results complement the recent genome and proteome analyses of SCs during peripheral nerve myelin formation. The results also reveal a key role of Sin3A-dependent chromatin organization in promoting myelinogenic programs and SC differentiation to control peripheral myelination and repair. These findings may inform new treatments for enhancing remyelination and nerve regeneration.
Subject(s)
Animals , Rats , Axons , Chromatin/metabolism , Gene Expression Profiling , Myelin Sheath/metabolism , Nerve Regeneration/physiology , Schwann Cells/metabolism , Sciatic Nerve/injuriesABSTRACT
Objective • To investigate the expression of miR-218-2-3P in NK/T-cell lymphoma, and the effect of miR-218-2-3P on the proliferation, apoptosis and cycle of NK/T-cell lymphoma by targeting SIN3A. Methods • Quantitative real-time PCR (qPCR) was used to detect the expressions of miR-218-2-3P in normal NK cells and NK/T-cell lymphoma cells NK92MI and NKYS. Lipofectamine 3000 was used to transfect the inhibitor containing nonsense sequences (inhibitors NC), miR-218-2-3P inhibitor and the same dose of transfection reagent without any fragment into NK92MI cells, which were divided into three groups. qPCR and Western blotting were used to detect the expression levels of miR-218-2-3P and SIN3A protein in the inhibitor NC group, the miR-218-2-3P inhibitor group and the blank control group, respectively. The cell proliferation activities of the three group were measured by CCK8 method. The apoptosis rates and cell cycles of the three group were determined by flow cytometry. The double luciferase reporter gene assay was performed to detect whether SIN3A was a target gene of miR-218-2-3P. NK92MI cells were transfected with miR-218-2-3P inhibitor+SIN3A small interfering RNA (si-SIN3A) and miR-218-2-3P inhibitor+nonsense sequences small interfering RNA (si-NC), respectively, which were divided into two groups. The cell proliferation activities of the two groups were detected by CCK8 method. Results • Compared with the normal NK cells, the expressions of miR-218-2-3P in NK92MI and NKYS cells significantly increased (both P<0.05). Compared with the blank control group and the inhibitor NC group, the proliferation activity of NK92MI cells in the miR-218-2-3P inhibitor group decreased (both P<0.05), the apoptosis rate increased (both P<0.05) and cell cycle arrest occurred in G0/G1 phase (both P<0.05). The double luciferase reporter gene assay showed that SIN3A was the target gene of miR-218-2- 3P. Compared with the blank control group and the inhibitor NC group, the SIN3A protein expression of the miR-218-2-3P inhibitor group was increased (both P<0.05). The down-regulation of SIN3A expression could restore the proliferation activity of cells weakened by miR-218-2-3P inhibitor (both P<0.05). Conclusion • miR-218-2-3P is highly expressed in the NK92MI and NKYS cell lines. miR-218-2-3P may affect the proliferation, apoptosis and cycle of NK/T-cell lymphoma through targeted regulation of SIN3A.