Microsporidian Nosema bombycis secretes serine protease inhibitor to suppress host cell apoptosis via Caspase BmICE

• DOI: 10.1371/journal.ppat.1012373
• Publication Date: 2025-01-07T18:47:27Z
• Authors: Maoshuang Ran; Jialing Bao; Boning Li; Yulian Shi; Wenxin Yang; Xianzhi Meng; Jie Chen; Junhong Wei; Mengxian Long; Tian Li; Chunfeng Li; Guoqing Pan; Zeyang Zhou
• Keywords: Intracellular parasite

Microsporidia are a group of intracellular pathogens that actively manipulate host cell biological processes to facilitate their niche. Apoptosis is an important defense mechanism by which control pathogens. modulating apoptosis has been reported previously, however the molecular not yet clear. In this report, we describe microsporidia Nosema bombycis inhibits Bombyx mori cells through secreted protein NbSPN14, serine protease inhibitor (Serpin). An immunofluorescent assay demonstrated upon infection with N . , NbSPN14 was initially found in B cytoplasm and then became enriched nucleus. Overexpression RNA-interference (RNAi) mori’ embryo confirmed inhibited apoptosis. Immunofluorescent Co-IP assays verified co-localization interaction BmICE, Caspase 3 homolog Knocking out BmICE or mutating BmICE-interacting P1 site eliminated localization into nucleus prevented apoptosis-inhibiting effect also proved between occurred translocation depends on BmICE. These data elucidate secretory directly inhibiting provides insight for understanding pathogen-host interactions potential therapeutic target proliferation.