Prototheca zopfii genotype II induces mitochondrial apoptosis in models of bovine mastitis
Prototheca zopfii genotype II induces mitochondrial apoptosis in models of bovine mastitis
复制标题
Prototheca zopfii 基因型 II 诱导牛乳腺炎模型中线粒体凋亡
DOI：
10.1038/s41598-020-57645-z
复制
发表时间：
2020-01-20
影响因子：
4.6
通讯作者：
Han, Bo
中科院分区：
文献类型：
--
作者：
Shahid, Muhammad;Cobo, Eduardo R.;Han, Bo
佐氏无绿藻是一种越来越多地从牛乳房炎中分离出来的细菌。在两种基因型（基因型I和II（GT-I和-II））的佐氏毕赤酵母中，佐氏毕赤酵母GT-II是与急性乳腺炎和产奶量减少相关的基因型，尽管其发病机制尚不清楚。目的是确定在培养的乳腺上皮细胞（来自牛和小鼠）和小鼠巨噬细胞中以及使用乳腺炎小鼠模型中，佐氏毕赤酵母GT-II的炎症和凋亡作用。通过末端脱氧核苷酸转移酶介导的脱氧尿苷三磷酸缺口末端标记法测定，Prototheca zopfii GT-II（而不是GT-I）侵入牛和小鼠乳腺上皮细胞（MEC）并诱导细胞凋亡。这种佐氏毕赤酵母GT-II驱动的细胞凋亡对应于线粒体途径;线粒体跨膜阻力（Delta Psi m）改变，并且对线粒体介导的细胞凋亡调节基因的调节改变（增加转录Bax、细胞色素-c和Apaf-1，下调Bcl-2），而半胱天冬酶-9和-3表达增加。与MEC相比，巨噬细胞中佐氏毕赤酵母GT-II的凋亡作用更明显。在鼠乳腺感染模型中，佐氏毕赤酵母GT-II在乳腺中复制并引起严重炎症，伴有巨噬细胞和嗜中性粒细胞浸润以及促炎基因（TNF-α、IL-1 β和Cxcl-1）上调以及上皮细胞凋亡。因此，我们得出结论，P. zopfii GT-II是一种引起乳腺炎的病原体，可引发严重的炎症和线粒体凋亡。
Prototheca zopfii is an alga increasingly isolated from bovine mastitis. Of the two genotypes of P. zopfii (genotype I and II (GT-I and -II)), P. zopfii GT-II is the genotype associated with acute mastitis and decreased milk production, although its pathogenesis is not well known. The objective was to determine inflammatory and apoptotic roles of P. zopfii GT-II in cultured mammary epithelial cells (from cattle and mice) and murine macrophages and using a murine model of mastitis. Prototheca zopfii GT-II (but not GT-I) invaded bovine and murine mammary epithelial cells (MECs) and induced apoptosis, as determined by the terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labeling assay. This P. zopfii GT-II driven apoptosis corresponded to mitochondrial pathways; mitochondrial transmembrane resistance (Delta Psi m) was altered and modulation of mitochondrion-mediated apoptosis regulating genes changed (increased transcriptional Bax, cytochrome-c and Apaf-1 and downregulated Bcl-2), whereas caspase-9 and -3 expression increased. Apoptotic effects by P. zopfii GT-II were more pronounced in macrophages compared to MECs. In a murine mammary infection model, P. zopfii GT-II replicated in the mammary gland and caused severe inflammation with infiltration of macrophages and neutrophils and upregulation of pro-inflammatory genes (TNF-alpha, IL-1 beta and Cxcl-1) and also apoptosis of epithelial cells. Thus, we concluded P. zopfii GT-II is a mastitis-causing pathogen that triggers severe inflammation and also mitochondrial apoptosis.