Plöhn Ole, Singh Abhishek Kumar, Greger Clara, Wolfgramm Hannes, Baglanova Madina, Surmann Kristin, Völker Uwe, Bröker Barbara M, Becker Karsten, Seifert Ulrike, Cammann Clemens
Friedrich Loeffler - Institute of Medical Microbiology, University Medicine Greifswald, Greifswald, Germany.
Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany.
Front Cell Infect Microbiol. 2025 Aug 11;15:1597830. doi: 10.3389/fcimb.2025.1597830. eCollection 2025.
Intracellular invasion and persistence of can lead to chronic infection and is an effective strategy for the pathogen to evade the host immune response and antibiotic therapy. Selective ubiquitination of bacterial surfaces via E3 ubiquitin ligases is a mechanism by which host cells combat intracellular bacteria and target them for autophagosomal degradation. However, knowledge of the E3 ligases involved in intracellular recognition of is still very limited.
We studied A549 lung epithelial cells during infection, focusing on the role of the E3 ligase leucine rich repeat and sterile alpha motif containing 1 (LRSAM1). We used the CRISPR-Cas9 system to generate LRSAM1-deficient A549 cells and monitored intracellular bacterial survival, activation of host cellular signalling pathways related to cytokine production, and host cell death during infection.
In LRSAM1-deficient host cells we observed a significant increase in intracellular bacterial load, which was accompanied by an increased host cell death and elevated secretion of the pro-inflammatory cytokine IL-6. Despite induced selective autophagy, LRSAM1 knockout host cells were incapable of lowering and eliminating the pathogen, which seems to be caused by the reduced ubiquitination of the bacterial surface.
The results indicate a significant role of LRSAM1 in the clearance of intracellular . This contributes to a deeper understanding of the host cellular responses to infection and will facilitate the development of novel therapeutic strategies to combat intracellularly persistent .
[病原体名称]的细胞内侵袭和持续存在可导致慢性感染，是病原体逃避宿主免疫反应和抗生素治疗的有效策略。宿主细胞通过E3泛素连接酶对细菌表面进行选择性泛素化是一种对抗细胞内细菌并将其靶向自噬体降解的机制。然而，关于参与细胞内识别[病原体名称]的E3连接酶的了解仍然非常有限。
我们研究了感染[病原体名称]期间的A549肺上皮细胞，重点关注E3连接酶富含亮氨酸重复序列和无菌α基序蛋白1（LRSAM1）的作用。我们使用CRISPR-Cas9系统生成LRSAM1缺陷的A549细胞，并监测感染[病原体名称]期间细胞内细菌的存活情况、与细胞因子产生相关的宿主细胞信号通路的激活以及宿主细胞死亡情况。
在LRSAM1缺陷的宿主细胞中，我们观察到细胞内细菌载量显著增加，同时宿主细胞死亡增加，促炎细胞因子IL-6的分泌升高。尽管诱导了选择性自噬，但LRSAM1基因敲除的宿主细胞无法降低和清除病原体，这似乎是由于细菌表面泛素化减少所致。
结果表明LRSAM1在清除细胞内[病原体名称]方面发挥重要作用。这有助于更深入地了解宿主细胞对[病原体名称]感染的反应，并将促进开发对抗细胞内持续存在的[病原体名称]的新型治疗策略。
