Spyrou Giannis, Appelgren Daniel, Rosén Anders, Ingelsson Björn
Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.
Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden.
Front Cell Dev Biol. 2020 Jul 22;8:634. doi: 10.3389/fcell.2020.00634. eCollection 2020.
How do you wash cells? Three out of four of our colleagues use experimental procedures during everyday lab-bench work that can severely impair data interpretation depending on how cells are handled. We show here that a subpopulation (2-3%) of human leukocytes immediately induce a yet unclassified lytic cell death, concomitant with discharge of chromatin entities and cell elimination, when placed in protein-free solutions (i.e., PBS and HBSS). DNA release was not restricted to hematopoietic cells but occurred also in HEK293T cells. Albumin, fetal bovine serum, polyethylene glycol, and Pluronic F-68 supplements prevented chromatin discharge. Expelled chromatin was devoid of surrounding membranes but maintained its original nuclear shape, although ∼10 times enlarged. These structures differed from DNA appearance after osmotic or detergent-induced cell lysis. Besides sounding a cautionary note to the neutrophil extracellular trap (NET) research community, in which ∼50% of all published studies used protein-free media for NET-formation, our study also provides a rapid tool for analysis of chromatin organization.
如何清洗细胞？在日常实验台工作中，我们四分之三的同事所采用的实验步骤，可能会因细胞处理方式而严重影响数据解读。我们在此表明，当置于无蛋白溶液（即PBS和HBSS）中时，人类白细胞的一个亚群（2%-3%）会立即引发一种尚未分类的溶解性细胞死亡，同时伴随着染色质实体的释放和细胞清除。DNA释放并不局限于造血细胞，在HEK293T细胞中也会发生。白蛋白、胎牛血清、聚乙二醇和普朗尼克F-68补充剂可防止染色质释放。排出的染色质没有周围的膜，但保持其原来的核形状，尽管放大了约10倍。这些结构与渗透或去污剂诱导的细胞裂解后的DNA外观不同。除了向中性粒细胞胞外陷阱（NET）研究界敲响警钟外（在所有已发表的研究中，约50%使用无蛋白培养基来形成NET），我们的研究还提供了一种快速分析染色质组织的工具。
