High-mobility group box 1 (HMGB1) is a nuclear protein highly conserved in eukaryotes and ubiquitously expressed to regulate transcription and chromatin remodeling. Dorsal switch protein 1 (DSP1) is its insect homolog. A lepidopteran DSP1 acts as a damage-associated molecular pattern (DAMP) in response to immune challenge. The objective of this study was to determine the role of DAMP in the mealworm beetle, Tenebrio molitor, a coleopteran insect. DSP1 of T. molitor (Tm-DSP1) encodes 536 amino acids and shares sequence similarities with Homo sapiens HMGB1 (56.3%) and Spodoptera exigua DSP1 (59.2%). An antisera raised against S. exigua DSP1 was cross-reactive to Tm-DSP1. Like other insect DSPs, Tm-DSP1 has a relatively long N-terminal extension in addition to two conserved HMG box domains. It was expressed in all developmental stages of T. molitor and different larval tissues. Upon immune challenge, its expression level was upregulated. Its RNA interference (RNAi) treatment resulted in a significant reduction in immune responses measured by hemocyte nodule formation against bacterial infection. In addition, the induction of some antimicrobial peptide genes to the immune challenge was suppressed by its RNAi treatment. Interestingly, phospholipase A₂ associated with eicosanoid biosynthesis was significantly suppressed in its catalytic activity by the RNAi treatment specific to Tm-DSP1 expression. Without any pathogen infection, injection of a lepidopteran DSP1 induced both cellular and humoral immune responses. These results suggest that Tm-DSP1 in T. molitor can act as a DAMP molecule and mediate immune responses upon immune challenge.

中文翻译：

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黄粉虫的 HMGB1 样背侧开关蛋白 1，黄粉虫，作为一种损伤相关的分子模式

高迁移率组框 1 (HMGB1) 是一种在真核生物中高度保守的核蛋白，广泛表达以调节转录和染色质重塑。背侧开关蛋白 1 (DSP1) 是其昆虫同源物。鳞翅目 DSP1 作为一种损伤相关分子模式 (DAMP) 来响应免疫挑战。本研究的目的是确定 DAMP 在黄粉虫甲虫黄粉虫（一种鞘翅目昆虫）中的作用。的DSP1黄粉虫（TM-DSP1）编码536种氨基酸和共享序列相似性与智人HMGB1（56.3％）和甜菜夜蛾DSP1（59.2％）。针对S. exigua DSP1的抗血清与Tm-DSP1有交叉反应. 与其他昆虫 DSP 一样，Tm-DSP1除了两个保守的 HMG 框域外，还具有相对较长的 N 端延伸。它在T. molitor 的所有发育阶段和不同的幼虫组织中均有表达。在免疫攻击后，其表达水平上调。其 RNA 干扰 (RNAi) 处理导致通过血细胞结节形成对细菌感染的免疫反应显着降低。此外，一些抗菌肽基因对免疫攻击的诱导受到其 RNAi 治疗的抑制。有趣的是，Tm-DSP1特异性 RNAi 处理显着抑制了与类花生酸生物合成相关的磷脂酶 A ₂的催化活性表达。在没有任何病原体感染的情况下，注射鳞翅目 DSP1 可诱导细胞和体液免疫反应。这些结果表明，TM-DSP1在黄粉虫可以作为对免疫的挑战潮湿分子介导免疫应答作用。