低氧条件下颌骨骨髓间充质干细胞生物学活性及长链非编码RNAs表达谱差异的分析

Biological activity and expression profile of long non-coding RNAs in jaw bone marrow-derived mesenchymal stem cells under hypoxic condition

  • 摘要:
    背景 近年来,颌骨骨髓间充质干细胞(jaw bone marrow-derived mesenchymal stem cell,JBMMSCs)以其优秀的生物学特性备受瞩目。低氧作为一种常见的微环境,在增强JBMMSCs抗性方面发挥的作用尚未见报道,值得探究。
    目的 探索低氧对JBMMSCs生物学活性的影响以及低氧处理JBMMSCs后差异表达的长链非编码RNA(long non-coding RNAs,lncRNAs)及mRNAs,为进一步探究lncRNAs在调控JBMMSCs生物学性能中的作用机制提供理论基础。
    方法 从C57BL/6N小鼠下颌骨中分离培养JBMMSCs并对其进行鉴定。利用50 µmol/L氯化钴(CoCl2)培养JBMMSCs,建立JBMMSCs低氧细胞模型,以常氧条件下细胞为对照,通过免疫荧光、Western blot检测低氧诱导因子-1α(hypoxia-inducible factor-1α,HIF-1α)的表达情况,对细胞模型进行验证。在此基础上,区分低氧和常氧组,通过CCK-8、细胞划痕实验及Ki67免疫荧光染色观察低氧对JBMMSCs增殖、迁移等的影响。对低氧及常氧条件下的JBMMSCs进行高通量测序,以|log2FC|≥1且P<0.05为筛选标准,筛选差异表达的lncRNAs和mRNAs,并对其生物学功能和作用机制进行预测。
    结果 从小鼠下颌骨中提取的JBMMSCs呈长梭形、漩涡状生长,经鉴定符合间充质干细胞特点。采用50 µmol/L CoCl2处理72 h后低氧标记物HIF-1α表达较对照组升高(P=0.0023)。CCK-8和Ki67免疫荧光染色结果显示,低氧可促进JBMMSCs的增殖能力(P=0.0057)。细胞划痕实验结果显示,低氧可增强JBMMSCs迁移能力(P=0.0040)。利用高通量测序技术,筛选出低氧条件下12个差异表达的lncRNAs,其中4个表达上调,8个表达下调。利用生物信息学分析对差异最为显著的lncRNA-4632427E13Rik的下游miRNAs和靶基因进行预测,初步形成lncRNA-miRNA-mRNA互作网络。通过GO和KEGG分析发现,低氧处理后可显著富集到14条信号通路,并且其中多条信号通路可能与调控干细胞增殖分化和可塑性维持相关。
    结论 低氧可促进JBMMSCs的增殖、迁移等能力,预测lnc-4632427E13Rik可能在低氧调控JBMMSCs生物学性能过程中发挥作用。

     

    Abstract:
    Background In recent years, jaw bone marrow-derived mesenchymal stem cells (JBMMSCs) have drawn attentions for their good biological characteristics. As a common microenvironment, low oxygen plays a major role in enhancing MSCs resistance and is worthy of further exploration. However, the effect of lncRNAs on the regulation of the biological performance of JBMMSCs is not yet reported.
    Objective To investigate the effect of hypoxia on the biological activity of JBMMSCs and the differentially expressed lncRNAs and mRNAs after hypoxic treatment, so as to provide theoretical references for further exploring the mechanism of lncRNAs in regulating the biological properties of JBMMSCs.
    Methods JBMMSCs were isolated and cultured, and their mesenchymal stem cell characteristics were identified. JBMMSCs were stimulated with 50 µmol/L cobalt chloride (CoCl2) to establish a hypoxic cell model of JBMMSCs, and the expression of hypoxia-inducible factor-1α (HIF-1α) was detected by immunofluorescence and Western blot to verify the cell model. The effects of hypoxia on the proliferation, migration and other biological activities of JBMMSCs were observed by CCK-8, cell scratch test and Ki67 immunofluorescence staining. High-throughput sequencing was performed in JBMMSCs under hypoxic and normoxic conditions, and |log2FC|≥1 and P<0.05 was applied for screening criteria, so as to screen differentially expressed lncRNAs and mRNAs and forecast its biological function and mechanism of action.
    Results JBMMSCs extracted from the mouse jaw grew in a long fusiform and whirlpool shape, which was identified as mesenchymal stem cells. After treatment with 50 µmol/L CoCl2 for 72 hours, the expression of HIF-1α, a marker of hypoxia, was significantly higher than that of the control group (P=0.0023), suggesting that the hypoxic cell model was successfully established. CCK-8 and Ki67 immunofluorescence staining results showed that the proliferation ability of JBMMSCs was significantly increased under hypoxia (P=0.0057). Wound healing assay showed that hypoxia significantly enhanced the migration ability of JBMMSCs (P=0.0040). Using high-throughput sequencing technology, we identified 12 differentially expressed lncRNAs under hypoxia, of which 4 were up-regulated and 8 were down-regulated. Bioinformatics analysis was used to predict the downstream miRNAs and target genes of lncRNA-4632427E13Rik with the most significant difference, and an interaction network of lncRNA-miRNA-Mrna was preliminarily formed. Through GO and KEGG analysis, 14 signaling pathways were significantly enriched after hypoxia treatment, and many of them might be related to the regulation of stem cell proliferation, differentiation and plasticity maintenance.
    Conclusion Hypoxia can promote the proliferation, migration and other activities of JBMMSCs, and lnc-4632427E13Rik may play a role in the regulation of biological properties of JBMMSCs under hypoxia.

     

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