Functional impact of integrin α5β1 on the homeostasis of intervertebral discs: a study of mechanotransduction pathways using a novel dynamic loading organ culture system.
Functional impact of integrin α5β1 on the homeostasis of intervertebral discs: a study of mechanotransduction pathways using a novel dynamic loading organ culture system.
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DOI：
10.1016/j.spinee.2014.12.143
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发表时间：
2015-03-01
期刊：
影响因子：
--
通讯作者：
Nishida K
中科院分区：
文献类型：
--
作者：
Kurakawa T;Kakutani K;Morita Y;Kato Y;Yurube T;Hirata H;Miyazaki S;Terashima Y;Maeno K;Takada T;Doita M;Kurosaka M;Inoue N;Masuda K;Nishida K
椎间盘（IVD）退变是腰痛的主要原因，被认为是由日常机械负荷引起的。众所周知，机械应力会影响许多细胞类型中的细胞存活和细胞外基质代谢。尽管已有报道整合素α5β1跨膜机械受体参与IVD变性，但整合素α5β1的确切功能仍不清楚。使用动态加载器官培养系统反映IVD组织对机械应力的反应，并阐明整合素α5β1对IVD变性病理机制的功能影响。使用动态加载器官培养系统的离体研究。检查了96个大鼠IVD外植体。在存在或不存在对整合素α5β1的纤连蛋白结合位点具有亲和力的Arg-Gly-Asp（RGD）肽的情况下，使椎间盘经受1.3 MPa、1.0 Hz的动态压缩载荷。评估细胞活力和组织形态学。免疫组化法检测整合素α5β1在IVD中的定位。使用实时逆转录-聚合酶链反应评价IVD细胞的基因表达水平。在髓核（NP），细胞密度和活力减少的动态压缩负荷。组织学退行性改变主要见于NP，即NP细胞的形态学改变。在NP和纤维环（AF）中，免疫组织化学显示整合素α5β1的定位，并且整合素α5β1的信使RNA表达通过动态负荷而增加。动态负荷诱导的分解代谢作用，刺激基质金属蛋白酶-3和-13基因表达的NP和AF细胞。RGD肽部分阻断了组织学改变和分解代谢作用。动态加载器官培养系统模拟细胞对IVD机械加载的反应。我们的研究结果表明，IVD细胞通过RGD整合素识别机械应力，特别是在NP和AF细胞中高度表达的α5β1亚型。使用该系统的进一步实验将通过机械转导途径提供关于IVD变性的病理机制的信息。
Intervertebral disc (IVD) degeneration, a major cause of low back pain, is considered to be induced by daily mechanical loading. Mechanical stress is widely known to affect cell survival and extracellular matrix metabolism in many cell types. Although the involvement of integrin α5β1 transmembrane mechanoreceptor in IVD degeneration has been reported, the precise function of integrin α5β1 remains obscure. To reflect IVD tissue response to mechanical stress using a dynamic loading organ culture system and elucidate the functional impact of integrin α5β1 on the pathomechanism of IVD degeneration. An ex vivo study using a dynamic loading organ culture system. Ninety-six rat IVD explants were examined. Intervertebral discs were subjected to 1.3 MPa, 1.0 Hz dynamic compressive load in the presence or absence of an Arg-Gly-Asp (RGD) peptide with affinity to the fibronectin binding-site of integrin α5β1. Cell viability and histomorphology were assessed. The localization of integrin α5β1 in the IVD was assessed by immunohistochemistry. Gene expression levels of IVD cells were evaluated using real-time reverse transcription-polymerase chain reaction. In the nucleus pulposus (NP), cell density and viability were reduced by dynamic compressive load. Histologic degenerative alterations, mainly seen in the NP, were the morphologic changes of NP cells. In both NP and annulus fibrosus (AF), immunohistochemistry revealed localization of integrin α5β1 and that the messenger-RNA expression of integrin α5β1 was increased by dynamic load. Dynamic load induced a catabolic effect, the stimulation of matrix metalloproteinase-3 and -13 gene expressions by NP and AF cells. The RGD peptide partially blocked the histologic alterations and the catabolic effect. The dynamic loading organ culture system simulated cellular responses to mechanical loading of the IVD. Our results suggest that IVD cells recognize the mechanical stress through RGD integrins, particularly the α5β1 subtype that is highly expressed in NP and AF cells. Further experiments using this system will provide information about pathomechanisms of IVD degeneration through the mechanotransduction pathways.
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影响因子：
3.3
作者：
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