Reactive oxygen species are responsible for the cell aggregation and production of pro-inflammatory mediators in phorbol ester (PMA)-treated U937 cells on gelatin-coated dishes through upregulation of autophagy. (4th July 2019)

• Record Type: Journal Article
• Authors: Zhao, Ye-Li; Zhang, Xuan; Liu, Wei-Wei; Yang, Yu-Ting; Gao, Zhuo-Kun; Liu, Xiao-Ling; Liu, Wei; Hayashi, Toshihiko; Yamato, Masayuki; Fujisaki, Hitomi; Hattori, Shunji; Mizuno, Kazunori; Atsuzawa, Yuji; Tashiro, Shin-ichi; Onodera, Satoshi; Ikejima, Takashi
• Is Part Of: Connective tissue research. Volume 60:Number 4(2019)
• Page Start: 323
• Page End: 334
• Publication Date: 2019-07-04
• Subjects: Autophagy -- gelatin -- multicellular aggregates -- pro-inflammatory mediators -- ROS; Connective tissues -- Periodicals; 616.770072
• DOI: 10.1080/03008207.2018.1530770
• Languages: English
• ISSNs: 0300-8207

Abstract

ABSTRACT: Purpose : Our previous studies indicate that phorbol 12-myristate 13-acetate (PMA)-treated U937 cells cultured on collagen I-coated dishes express lowered production of pro-inflammatory mediators in parallel through reduced reactive oxygen species (ROS) levels. By contrast, PMA-treated U937 cells on gelatin, the denatured collagen, show enhanced production of pro-inflammatory mediators, mediated by up-regulating autophagy levels. The present study is aimed to investigate the effect of ROS levels in PMA-treated U937 cells cultured on gelatin-coated surface. Material and methods : MTT assay, flow cytometric analysis of ROS and autophagy, biochemical detection of antioxidant levels, enzyme-linked immunosorbent assay, and western blot were used. Results : Gelatin-coating increased ROS levels in PMA-treated U937 cells. Increased ROS levels are involved in the regulation of cell aggregation and the release of pro-inflammatory mediators in gelatin-coated culture. These results lead to the query about the crosstalk between the two positive regulators, the autophagy and ROS. Autophagy induction is attenuated by N -acetyl-L-cysteine treatment, but the treatment with autophagy inhibitor, 3-methyladenine, does not affect ROS levels, suggesting ROS are upstream of autophagy in the regulation axis of differentiated U937 cells on gelatin-coated surface. Further study confirmed that upregulation of autophagy was responsible for ROS-induced cell aggregation and production of pro-inflammatory mediators. Conclusion : The results suggest that gelatin-coating promotes the aggregation of PMA-treated U937 cells and the production of pro-inflammatory mediators by ROS-autophagy signaling pathway.