Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, QLD, Australia.
School of Science, Technology and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, Australia.
Front Endocrinol (Lausanne). 2022 Jun 17;13:891714. doi: 10.3389/fendo.2022.891714. eCollection 2022.
Teneurin C-terminal associated peptide (TCAP) is an ancient bioactive peptide that is highly conserved in metazoans. TCAP administration reduces cellular and behavioral stress in vertebrate and urochordate models. There is little information for invertebrates regarding the existence or function of a TCAP. This study used the Sydney rock oyster (SRO) as a molluscan model to characterize an invertebrate TCAP, from molecular gene analysis to its physiological effects associated with hemocyte phagocytosis. We report a single gene (and 4 splice variants), which encodes a precursor with TCAP that shares a vertebrate-like motif, and is similar to that of other molluscan classes (gastropod, cephalopod), arthropods and echinoderms. TCAP was identified in all SRO tissues using western blotting at 1-2 different molecular weights (~22 kDa and ~37kDa), supporting precursor cleavage variation. In SRO hemolymph, TCAP was spatially localized to the cytosol of hemocytes, and with particularly high density immunoreactivity in granules. Based on 'pull-down' assays, the SRO TCAP binds to GAPDH, suggesting that TCAP may protect cells from apoptosis under oxidative stress. Compared to sham injection, the intramuscular administration of TCAP (5 pmol) into oysters modulated their immune system by significantly reducing hemocyte phagocytosis under stress conditions (low salinity and high temperature). TCAP administration also significantly reduced hemocyte reactive oxygen species production at ambient conditions and after 48 h stress, compared to sham injection. Transcriptomic hemocyte analysis of stressed oysters administered with TCAP demonstrated significant changes in expression of genes associated with key metabolic, protective and immune functions. In summary, this study established a role for TCAP in oysters through modulation of physiological and molecular functions associated with energy conservation, stress and cellular defense.
腱膜蛋白 C 端相关肽（TCAP）是一种高度保守的古老生物活性肽，存在于后生动物中。TCAP 的给药可减少脊椎动物和尾索动物模型中的细胞和行为应激。关于无脊椎动物中 TCAP 的存在或功能知之甚少。本研究使用悉尼岩蚝（SRO）作为软体动物模型，从分子基因分析到与血细胞吞噬作用相关的生理效应，对无脊椎动物的 TCAP 进行了表征。我们报告了一个单一的基因（和 4 个剪接变体），该基因编码一个具有 TCAP 的前体，其具有类似脊椎动物的基序，并且与其他软体动物类群（腹足纲、头足纲）、节肢动物和棘皮动物相似。使用 Western blot 在 1-2 种不同的分子量（约 22 kDa 和约 37 kDa）下在所有 SRO 组织中鉴定出 TCAP，支持前体切割变化。在 SRO 血淋巴中，TCAP 定位于血细胞的细胞质中，在颗粒中具有特别高的免疫反应密度。基于“下拉”测定，SRO TCAP 与 GAPDH 结合，表明 TCAP 可能在氧化应激下保护细胞免受细胞凋亡。与假注射相比，TCAP（5 pmol）肌肉内给药可显著降低应激条件下（低盐度和高温）的血细胞吞噬作用，从而调节牡蛎的免疫系统。与假注射相比，TCAP 给药还可显著降低环境条件下和 48 小时应激后血细胞活性氧的产生。用 TCAP 给药的应激牡蛎的血细胞转录组分析表明，与关键代谢、保护和免疫功能相关的基因表达发生了显著变化。总之，本研究通过调节与能量守恒、应激和细胞防御相关的生理和分子功能，确立了 TCAP 在牡蛎中的作用。
