Effects of Simulated Microgravity on Functions of Neutrophil-like HL-60 Cells

Abstract

Altered gravity, especially microgravity affects cellular functions of immune cells and can result in immune dysfunction for long-term, manned spaceflight and space exploration. The underlying mechanism, however, of sensing and responding to the gravity alteration is poorly understood. Here, a rotary cell culture system (RCCS) bioreactor was used to elucidate the effects of simulated microgravity on polymorphonuclear neutrophils (PMN)-like HL-60 cells. Alteration of cell morphology, up-regulation of (nitric oxide) NO production, enhancement of interleukin-6 (IL-6), interleukin-8 (IL-8), and monocyte chemotactic protein 1 (MCP-1) secretion, and diversity of cellular adhesion molecule expression were observed for the cells cultured in RCCS, leading to the up-regulated inflammatory immune responses and host defense. It was also indicated that such alterations in biological responses of PMNs mediated the reduced rolling velocity and decreased adhesion of PMNlike HL-60 cells on endothelial cells under shear flow. This work furthers the understandings in the effects and mechanism of microgravity on PMN functions, which are Chengzhi Wang and Ning Li, both authors contributed equally to this work. Electronic supplementary material

Microgravity Modulates Effects of Chemotherapeutic Drugs on Cancer Cell Migration

“…We chose these cell lines because current in vivo models of AML and CML based on the use of patient samples are difficult to establish and manipulate in the laboratory and both HL60 and K562 are still being used as in vitro models for assessing the efficacy of chemotherapeutic agents [ 27 ]. Furthermore, HL60 and K562 have been used in microgravity studies [ 1 , 28 ]. Thus, our use of these cells enables the contextualization of our work for both terrestrial and space medical applications.…”

“…Through vertical rotation, the RCCS produces solid-body rotation of the entire HARV and the cell culture medium, randomizing the gravity vector to simulate microgravity [ 29 , 30 ]. We seeded HL60 and K562 cells at a concentration of 2 × 10 5 cells/mL in T-25 flasks (as static controls at normal gravity, 1 g ) and in 10 mL HARVs and rotated at 15 rpm (reported optimal rotation speed for many cells types including HL60 [ 28 , 31 ]) following the manufacturer’s protocols. Cells were kept in this microgravity condition for 48 h within a cell culture incubator ( Figure 1 ).…”

“…To closely replicate clinical dosage, we used Dox (Sigma 4458) at a final concentration of 5 μM [ 33 , 34 ] and Dauno (Sigma D8809) at a final concentration of 1 μM [ 19 , 32 ]. To ascertain the role of F-actin and thereby attain molecular level insights, we used 2 μM Cytochalasin D (CytoD) to depolymerize F-actin and assess its well-established impact on migration [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ].…”

Microgravity-Induced Alterations of Inflammation-Related Mechanotransduction in Endothelial Cells on Board SJ-10 Satellite

“…Ground-based microgravity effect simulation facilities, including rotating wall vessel (RWV) (a kind of two-dimensional (2D) clinostat) ( Goodwin et al, 1993 ), random positioning machine (RPM) (a kind of three-dimensional (3D) clinostat) ( Wuest et al, 2017 ) and other types of clinostats ( Siamwala et al, 2010 ; Kang et al, 2011 ), have been devoted to unravel the effect of time-averaged gravity vector on EC functions in more details. Specifically in the cascade of leukocyte recruitment onto endothelium, not only the adhesive receptor expression and chemokine secretion of neutrophils are altered in RWV ( Wang et al, 2015 ) but the adhesive ligand expression and inflammatory cytokine secretion of ECs are also modulated by this kind of simulation. Unfortunately, the outcomes are still controversial in the literatures.…”

Microgravity modulates effects of chemotherapeutic drugs on cancer cell migration

“…Through vertical rotation, the RCCS produces solid-body rotation of the entire HARV and the cell culture medium, randomizing the gravity vector to simulate microgravity (29,30). We seeded HL60 and K562 cells at a concentration of 2 x 10 5 cells/ml in T-25 flasks (as static controls at normal gravity, 1g) and in 10-ml HARVs and rotated at 15 rpm (reported optimal rotation speed for many cells types including HL60 (28,31) following the manufacturer's protocols. Cells were kept in this microgravity condition for 48 hours, within a cell culture incubator ( Fig.…”