Tessarin Gestter W L, Michalec Ola M, Torres-da-Silva Kelly R, Da Silva André V, Cruz-Rizzolo Roelf J, Gonçalves Alaide, Gasparini Daniele C, Horta-Júnior José A C, Ervolino Edilson, Bittencourt Jackson C, Lovejoy David A, Casatti Cláudio A
Department of Basic Sciences, School of Dentistry of Araçatuba, São Paulo State University (UNESP), Araçatuba, Brazil.
Department of Anatomy, Institute of Biosciences of Botucatu, São Paulo State University (UNESP), Botucatu, Brazil.
Front Neurosci. 2019 Jun 27;13:655. doi: 10.3389/fnins.2019.00655. eCollection 2019.
Teneurins are type II transmembrane proteins comprised of four phylogenetically conserved homologs (Ten-1-4) that are highly expressed during neurogenesis. An additional bioactive peptide named teneurin C-terminal-associated peptide (TCAP-1-4) is present at the carboxyl terminal of teneurins. The possible correlation between the Ten/TCAP system and brain injuries has not been explored yet. Thus, this study examined the expression of these proteins in the cerebral cortex after mechanical brain injury. Adult rats were subjected to cerebral cortex injury by needle-insertion lesion and sacrificed at various time points. This was followed by analysis of the lesion area by immunohistochemistry and conventional RT-PCR techniques. Control animals (no brain injury) showed only discrete Ten-2-like immunoreactive pyramidal neurons in the cerebral cortex. In contrast, Ten-2 immunoreactivity was significantly up-regulated in the reactive astrocytes in all brain-injured groups ( < 0.0001) when compared to the control group. Interestingly, reactive astrocytes also showed intense immunoreactivity to LPHN-1, an endogenous receptor for the Ten-2 splice variant named Lasso. Semi-quantitative analysis of Ten-2 and TCAP-2 expression revealed significant increases of both at 48 h, 3 days and 5 days ( < 0.0001) after brain injury compared to the remaining groups. Immortalized cerebellar astrocytes were also evaluated for Ten/TCAP expression and intracellular calcium signaling by fluorescence microscopy after TCAP-1 treatment. Immortalized astrocytes expressed additional Ten/TCAP homologs and exhibited significant increases in intracellular calcium concentrations after TCAP-1 treatment. This study is the first to demonstrate that Ten-2/TCAP-2 and LPHN-1 are upregulated in reactive astrocytes after a mechanical brain injury. Immortalized cerebellar astrocytes expressed Ten/TCAP homologs and TCAP-1 treatment stimulated intracellular calcium signaling. These findings disclose a new functional role of the Ten/TCAP system in astrocytes during tissue repair of the CNS.
Ten-1蛋白是一种II型跨膜蛋白，由四个在系统发育上保守的同系物（Ten-1 - 4）组成，在神经发生过程中高度表达。在Ten-1蛋白的羧基末端存在一种名为Ten-1蛋白C末端相关肽（TCAP-1 - 4）的额外生物活性肽。Ten-1蛋白/TCAP系统与脑损伤之间的可能关联尚未得到探索。因此，本研究检测了机械性脑损伤后这些蛋白在大脑皮质中的表达。成年大鼠通过针刺损伤造成大脑皮质损伤，并在不同时间点处死。随后通过免疫组织化学和常规逆转录-聚合酶链反应技术分析损伤区域。对照动物（无脑损伤）在大脑皮质中仅显示离散的Ten-2样免疫反应性锥体细胞。相比之下，与对照组相比，所有脑损伤组中反应性星形胶质细胞中的Ten-2免疫反应性显著上调（P<0.0001）。有趣的是，反应性星形胶质细胞对LPHN-1也表现出强烈的免疫反应性，LPHN-1是名为套索（Lasso）的Ten-2剪接变体的内源性受体。与其余组相比，脑损伤后48小时、3天和5天Ten-2和TCAP-2表达的半定量分析显示两者均显著增加（P<0.0001）。在用TCAP-1处理后，还通过荧光显微镜评估了永生化小脑星形胶质细胞的Ten-1蛋白/TCAP表达和细胞内钙信号传导。永生化星形胶质细胞表达额外的Ten-1蛋白/TCAP同系物，并且在TCAP-1处理后细胞内钙浓度显著增加。本研究首次证明Ten-2/TCAP-2和LPHN-1在机械性脑损伤后的反应性星形胶质细胞中上调。永生化小脑星形胶质细胞表达Ten-1蛋白/TCAP同系物，并且TCAP-1处理刺激细胞内钙信号传导。这些发现揭示了Ten-1蛋白/TCAP系统在中枢神经系统组织修复过程中在星形胶质细胞中的新功能作用。
