Yañez Alejandro J, Beltrán Jorge F, Barrientos Claudia A, Soto-Rauch Genaro, Aguilar Marcelo, Isla Adolfo, Flores-Martin Sandra N, Yañez Francisco T, Yuivar Yassef, Ojeda Adriana, Almendras Felipe, Bustos Patricio, Mancilla Marcos
Departamento de Investigación y Desarrollo, Greenvolution SpA, Puerto Varas, Región de Los Lagos, Chile.
Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile.
Front Immunol. 2025 Jun 18;16:1570871. doi: 10.3389/fimmu.2025.1570871. eCollection 2025.
"In evolution's unending race, survival demands continuous adaptation- to stop is to fall behind." The Stimulator of Interferon Genes (STING) pathway embodies this principle, acting as a conserved master regulator of cytosolic DNA sensing from to salmon and humans. Although extensively characterized in mammals, its structural features and regulatory roles during intracellular bacterial infection in teleosts remain poorly defined.
We structurally characterized the ancestral STING ortholog from Atlantic salmon () using AlphaFold-guided modeling to identify conserved motifs, including the cyclic dinucleotide (CDN)-binding cleft and phosphorylation regulatory sites. Molecular docking simulations were performed to evaluate the interaction of a validated human STING agonist with salmonid STING. Transcriptomic analyses were conducted in immune tissues and SHK-1 macrophage-like cells infected with to assess gene expression dynamics.
Our models confirmed evolutionary conservation of key STING structural domains. Docking revealed a strong binding affinity between the human agonist and salmonid STING, supporting translational potential. Transcriptomics showed high expression in immune tissues, rapidly upregulated after infection. In SHK-1 cells, STING1, IFN-α, TNF-α, and IL-1β peaked at 4 hours post-infection (hpi), but this inflammatory burst collapsed by 5 days post-infection (dpi), despite persistent transcription, indicating functional uncoupling due to immune evasion. , prolonged DDX41-STING activation was associated with reduced pyroptosis, necroptosis, and inflammatory signaling, reflecting bacterial suppression mechanisms.
This study positions as a high-resolution model for STING biology and introduces the Evolutionary Molecular Immunity Race (EMIR) framework, where STING orchestrates immune fate across hundreds of millions of years of vertebrate evolution, and over the last ~80 million years within the salmonid lineage.
“在进化的无尽赛跑中，生存需要持续适应——停滞即落后。”干扰素基因刺激物（STING）通路体现了这一原则，它作为一种保守的胞质DNA感应主要调节因子，存在于从硬骨鱼到鲑鱼和人类等多种生物中。尽管在哺乳动物中已得到广泛研究，但其在硬骨鱼细胞内细菌感染过程中的结构特征和调节作用仍不清楚。
我们利用AlphaFold引导的建模技术对大西洋鲑鱼（Salmo salar）的原始STING直系同源物进行了结构表征，以识别保守基序，包括环二核苷酸（CDN）结合裂隙和磷酸化调节位点。进行分子对接模拟以评估经过验证的人类STING激动剂与鲑科鱼类STING的相互作用。在感染嗜水气单胞菌（Aeromonas hydrophila）的免疫组织和SHK-1巨噬细胞样细胞中进行转录组分析，以评估基因表达动态。
我们的模型证实了STING关键结构域的进化保守性。对接显示人类激动剂与鲑科鱼类STING之间具有很强的结合亲和力，支持其转化潜力。转录组学显示嗜水气单胞菌在免疫组织中高表达，感染后迅速上调。在SHK-1细胞中，STING1、IFN-α、TNF-α和IL-1β在感染后4小时（hpi）达到峰值，但尽管转录持续存在，这种炎症爆发在感染后5天（dpi）时消失，表明由于免疫逃避导致功能解偶联。此外，DDX41-STING的长期激活与焦亡、坏死性凋亡和炎症信号传导的减少有关，反映了细菌的抑制机制。
本研究将大西洋鲑鱼定位为STING生物学的高分辨率模型，并引入了进化分子免疫竞赛（EMIR）框架，其中STING在数亿年的脊椎动物进化过程中，以及在鲑科鱼类谱系的最后约8000万年中协调免疫命运。
