School of Marine Sciences, Ningbo University, Ningbo 315211, PR China.
School of Marine Sciences, Ningbo University, Ningbo 315211, PR China.
Comp Biochem Physiol Part D Genomics Proteomics. 2019 Jun;30:196-205. doi: 10.1016/j.cbd.2019.03.003. Epub 2019 Mar 13.
Skin ulceration syndrome (SUS) of sea cucumber is a common and serious disease that affects the stable development of Apostichopus japonicus in the culture industry. The part of sea cucumber that suffers from major injury and is directly observed is the body wall, in which protein variations should be the most direct evidence of the disease. To understand the response mechanisms of A. japonicus in SUS progression, we investigated protein changes in the body wall of diseased A. japonicus induced by Vibrio splendidus and individuals with natural diseases by isobaric tags for relative and absolute quantification (iTRAQ). About 119 proteins were identified in the two iTRAQ groups. A comparison of the protein expression profiles among two SUS conditions revealed that the mode of action induced by V. splendidus (Vs-SUS) was completely different from those in individuals with natural disease (ND-SUS). Most of the differentially expressed proteins (DEPs) (33 in 37 DEPs) were significantly depressed in the Vs-SUS group. Only 13 proteins in 27 DEPs showed similar trend to those in the ND-SUS group. Many important proteins involved in major intercellular signaling pathways associated with SUS disease were identified based on the KEGG and GO database search. Many proteins were located in the mitochondria and mainly involved in the oxidative stress pathway. Glutathione metabolism pathway was associated with reactive oxygen (ROS) production in the ND-SUS group. In the Vs-group, most of the proteins were concentrated in the cytoplasm and were related to immunity and extracellular matrix stability. In the ND-SUS group, the activity of key enzymes (CAT, GPx) that eliminate mitochondrial ROS production and structural stable protein (HSP60, HSP10) decreased, whereas those of complement proteins (C3, C3-2) that promoted ROS production was upregulated. This finding supported that oxidative damage caused by ROS might be the main effector for SUS in the ND-SUS group. The challenge with V. splendidus led to the breakdown of the defense capability of sea cucumber and suppressed the expression of immune-related proteins, such as C-type lectin, caspase, STAT, and cystatin. The downregulation of TIMP led to MMP1 overexpression. Members of the MMP family could directly degrade the extracellular matrix, which may be the main reason for the cell matrix degradation and induced SUS disease in the Vs-SUS group. Hence, ROS and extracellular matrix degradation enzymes could play important roles in the formation of SUS in sea cucumber. Results provide insights into the complex molecular mechanism of SUS in sea cucumber.
海参皮肤溃疡症（SUS）是一种常见且严重的疾病，会影响海参养殖产业的稳定发展。海参受到严重损伤并直接观察到的部分是体壁，其中蛋白质的变化应该是疾病的最直接证据。为了了解海参在 SUS 进展过程中的反应机制，我们通过比较副溶血弧菌诱导的患病海参和自然患病海参体壁的蛋白质变化，使用同位素质谱标签相对和绝对定量（iTRAQ）技术进行了研究。在两个 iTRAQ 组中鉴定出约 119 种蛋白质。对两种 SUS 条件下的蛋白质表达谱进行比较，发现副溶血弧菌诱导的作用模式（Vs-SUS）与自然患病个体（ND-SUS）完全不同。在 Vs-SUS 组中，大多数差异表达蛋白（33 个中的 37 个）显著下调。只有 27 个差异表达蛋白中的 13 个表现出与 ND-SUS 组相似的趋势。根据 KEGG 和 GO 数据库搜索，确定了许多与 SUS 疾病相关的重要的细胞间信号通路相关的重要蛋白。许多蛋白位于线粒体中，主要参与氧化应激途径。谷胱甘肽代谢途径与 ND-SUS 组中活性氧（ROS）的产生有关。在 Vs 组中，大多数蛋白集中在细胞质中，与免疫和细胞外基质稳定性有关。在 ND-SUS 组中，消除线粒体 ROS 产生的关键酶（CAT、GPx）和结构稳定蛋白（HSP60、HSP10）的活性降低，而促进 ROS 产生的补体蛋白（C3、C3-2）的活性升高。这一发现支持 ROS 引起的氧化损伤可能是 ND-SUS 组 SUS 的主要效应因子。副溶血弧菌的挑战导致海参防御能力的崩溃，并抑制了免疫相关蛋白，如 C 型凝集素、半胱天冬酶、STAT 和胱抑素的表达。TIMP 的下调导致 MMP1 过表达。MMP 家族成员可以直接降解细胞外基质，这可能是细胞基质降解和诱导 Vs-SUS 组 SUS 疾病的主要原因。因此，ROS 和细胞外基质降解酶可能在海参 SUS 的形成中发挥重要作用。结果为海参 SUS 的复杂分子机制提供了新的见解。
