Programa Cátedras CONACyT (Consejo Nacional de Ciencia y Tecnología), Centro de Investigaciones Biológicas del Noroeste, S.C. (CIBNOR), La Paz, Mexico.
Laboratorio de Toxinas Marinas y Aminoácidos, Centro de Investigaciones Biológicas del Noroeste, S.C. (CIBNOR), La Paz, Mexico.
Front Immunol. 2021 Apr 1;12:634497. doi: 10.3389/fimmu.2021.634497. eCollection 2021.
Programmed cell death (PCD) is an essential process for the immune system's development and homeostasis, enabling the remotion of infected or unnecessary cells. There are several PCD's types, depending on the molecular mechanisms, such as non-inflammatory or pro-inflammatory. Hemocytes are the main component of cellular immunity in bivalve mollusks. Numerous infectious microorganisms produce toxins that impair hemocytes functions, but there is little knowledge on the role of PCD in these cells. This study aims to evaluate whether marine toxins induce a particular type of PCD in hemocytes of the bivalve mollusk during 4 h at 25°C. Hemocytes were incubated with two types of marine toxins: non-proteinaceous toxins from microalgae (saxitoxin, STX; gonyautoxins 2 and 3, GTX2/3; okadaic acid/dynophysistoxin-1, OA/DTX-1; brevetoxins 2 and 3, PbTx-2,-3; brevetoxin 2, PbTx-2), and proteinaceous extracts from bacteria (, Vp; , Vc). Also, we used the apoptosis inducers, staurosporine (STP), and camptothecin (CPT). STP, CPT, STX, and GTX 2/3, provoked high hemocyte mortality characterized by apoptosis hallmarks such as phosphatidylserine translocation into the outer leaflet of the cell membrane, exacerbated chromatin condensation, DNA oligonucleosomal fragments, and variation in gene expression levels of apoptotic caspases 2, 3, 7, and 8. The mixture of PbTx-2,-3 also showed many apoptosis features; however, they did not show apoptotic DNA oligonucleosomal fragments. Likewise, PbTx-2, OA/DTX-1, and proteinaceous extracts from bacteria Vp, and Vc, induced a minor degree of cell death with high gene expression of the pro-inflammatory initiator caspase-1, which could indicate a process of pyroptosis-like PCD. Hemocytes could carry out both PCD types simultaneously. Therefore, marine toxins trigger PCD's signaling pathways in hemocytes, depending on the toxin's nature, which appears to be highly conserved both structurally and functionally.
程序性细胞死亡 (PCD) 是免疫系统发育和稳态的必要过程，使受感染或不必要的细胞得以清除。根据分子机制的不同，PCD 有几种类型，例如非炎症性或炎症性。血细胞是双壳类软体动物细胞免疫的主要成分。许多传染性微生物产生毒素，损害血细胞的功能，但对于 PCD 在这些细胞中的作用知之甚少。本研究旨在评估在 25°C 下孵育 4 小时后，海洋毒素是否会诱导双壳类软体动物血细胞发生特定类型的 PCD。血细胞与两种海洋毒素孵育：来自微藻的非蛋白毒素（石房蛤毒素，STX；GTX2/3 毒素，GTX2/3；冈田酸/戴尼菲西托因-1，OA/DTX-1；短裸甲藻毒素 2 和 3，PbTx-2，PbTx-3；短裸甲藻毒素 2，PbTx-2）和细菌的蛋白提取物（Vp；Vc）。此外，我们还使用了凋亡诱导剂，司他丁（STP）和喜树碱（CPT）。STP、CPT、STX 和 GTX2/3 引起了高血细胞死亡率，其特征是凋亡标志物，如磷脂酰丝氨酸向细胞膜外叶转移、染色质浓缩加剧、DNA 寡核苷酸片段和凋亡半胱天冬酶 2、3、7 和 8 的基因表达水平的变化。PbTx-2，PbTx-3 混合物也表现出许多凋亡特征；然而，它们没有表现出凋亡的 DNA 寡核苷酸片段。同样，PbTx-2、OA/DTX-1 和细菌 Vp、Vc 的蛋白提取物诱导了细胞死亡程度较低，促炎起始半胱天冬酶-1 的基因表达水平较高，这可能表明发生了类似于细胞焦亡的 PCD 过程。血细胞可以同时进行两种 PCD 类型。因此，海洋毒素根据毒素的性质，在血细胞中触发 PCD 的信号通路，这在结构和功能上似乎都是高度保守的。
