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Regulation of ICAM-1 in cells of the monocyte/macrophage system in microgravity.

Paulsen K, Tauber S, Dumrese C, Bradacs G, Simmet DM, Gölz N, Hauschild S, Raig C, Engeli S, Gutewort A, Hürlimann E, Biskup J, Unverdorben F, Rieder G, Hofmänner D, Mutschler L, Krammer S, Buttron I, Philpot C, Huge A, Lier H, Barz I, Engelmann F, Layer LE, Thiel CS, Ullrich O - Biomed Res Int (2015)

Bottom Line: In contrast, ICAM-1 expression increased in macrophage-like differentiated human U937 cells during the microgravity phase of parabolic flights and in long-term microgravity provided by a 2D clinostat or during the orbital SIMBOX/Shenzhou-8 mission.In nondifferentiated U937 cells, no effect of microgravity on ICAM-1 expression could be observed during parabolic flight experiments.Thus, ICAM-1 can be considered as a rapid-reacting and sustained gravity-regulated molecule in mammalian cells.

View Article: PubMed Central - PubMed

Affiliation: Institute of Anatomy, Faculty of Medicine, University of Zurich, Winterthurerstraß 190, 8057 Zurich, Switzerland.

ABSTRACT
Cells of the immune system are highly sensitive to altered gravity, and the monocyte as well as the macrophage function is proven to be impaired under microgravity conditions. In our study, we investigated the surface expression of ICAM-1 protein and expression of ICAM-1 mRNA in cells of the monocyte/macrophage system in microgravity during clinostat, parabolic flight, sounding rocket, and orbital experiments. In murine BV-2 microglial cells, we detected a downregulation of ICAM-1 expression in clinorotation experiments and a rapid and reversible downregulation in the microgravity phase of parabolic flight experiments. In contrast, ICAM-1 expression increased in macrophage-like differentiated human U937 cells during the microgravity phase of parabolic flights and in long-term microgravity provided by a 2D clinostat or during the orbital SIMBOX/Shenzhou-8 mission. In nondifferentiated U937 cells, no effect of microgravity on ICAM-1 expression could be observed during parabolic flight experiments. We conclude that disturbed immune function in microgravity could be a consequence of ICAM-1 modulation in the monocyte/macrophage system, which in turn could have a strong impact on the interaction with T lymphocytes and cell migration. Thus, ICAM-1 can be considered as a rapid-reacting and sustained gravity-regulated molecule in mammalian cells.

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Related in: MedlinePlus

Cytometry analysis of ICAM-1 expression in BV-2 microglial cells in simulated microgravity (2D clinorotation). BV-2 microglial cells were exposed to either clinorotation (μg), placed in the clinostat but not rotated (1 g control group), or cultured under standard cell culture conditions (incubator control) for 24 h. Cells were stained for ICAM-1 surface expression and analyzed by flow cytometry. The level of ICAM-1 surface expression is represented by the mean fluorescent intensity assessed by flow cytometry. (a) In forward/sideward scatter detection mode of flow cytometry, two gates were set to separate two subtypes of BV-2 microglial cells that appeared different in size and granulation (subtypes 1 and 2 in dot plots). (b) Distribution of BV-2 microglial cells in subtypes 1 and 2 after exposure to different gravity conditions. (c) Quantification of ICAM-1 expression after exposure to different gravity conditions within subtypes 1 and 2. Data are given as median ± SE (*P < 0.1, **P < 0.05, ***P < 0.01, n = 3, according to one-way ANOVA followed by Wilcoxon or unpaired t-test).
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fig2: Cytometry analysis of ICAM-1 expression in BV-2 microglial cells in simulated microgravity (2D clinorotation). BV-2 microglial cells were exposed to either clinorotation (μg), placed in the clinostat but not rotated (1 g control group), or cultured under standard cell culture conditions (incubator control) for 24 h. Cells were stained for ICAM-1 surface expression and analyzed by flow cytometry. The level of ICAM-1 surface expression is represented by the mean fluorescent intensity assessed by flow cytometry. (a) In forward/sideward scatter detection mode of flow cytometry, two gates were set to separate two subtypes of BV-2 microglial cells that appeared different in size and granulation (subtypes 1 and 2 in dot plots). (b) Distribution of BV-2 microglial cells in subtypes 1 and 2 after exposure to different gravity conditions. (c) Quantification of ICAM-1 expression after exposure to different gravity conditions within subtypes 1 and 2. Data are given as median ± SE (*P < 0.1, **P < 0.05, ***P < 0.01, n = 3, according to one-way ANOVA followed by Wilcoxon or unpaired t-test).

Mentions: First, we analyzed ICAM-1 expression in BV-2 microglial cells after 24 h clinorotation (60 rpm, 4 mm pipette diameter, maximal residual acceleration of 4 × 10−3 g at the outer radius of the pipette). The clinostat device was placed in an incubator, which provides constant 37°C. Fifteen serological pipettes rotated at the same time with 60 rpm. 1 g controls were placed at the ground plate of the clinostat without rotation but with the same environment condition like μg samples. A 1 g control group of BV-2 cells was filled into 1 mL serological pipettes in the same way as the clinorotation cell group but was not clinorotated. Another control group was kept at regular cell culture conditions in the incubator (37°C, 5% CO2). Cells were subsequently stained for cell surface ICAM-1, apoptosis (TUNEL), cell delineation (HCS CellMask), and DNA (DAPI) (Figure 2). ICAM-1 expression analysis by flow cytometry revealed two distinct subtypes of cells in the clinorotated group (μg group) compared to the 1 g control group and the incubator control group consisting of only one subtype, respectively (Figure 2(a)). The first of the two subtypes was small and stronger granulated (subtype 1) than the second subtype, which appears taller but less granulated (subtype 2). Apoptotic cells were excluded from the analysis by TUNEL staining. Subtype 1 could possibly represent an activated state. Subtype 1 was found in the μg group as well as in the 1 g control group, whereas the incubator control did virtually not contain this subtype. Subtype 2 was represented in all three cell groups, μg, 1 g control, and incubator control cell group. However, it was primarily present in the μg and in the incubator control group and less present in the 1 g control group. The population distribution within cell groups is illustrated in Figure 2(b), showing the relative cell numbers of each population in each cell group. Since the incubator control group consisted almost exclusively of cells in subtype 2, this number was nearly 100%, whereas subtype 1 was close to 0%. The μg group had almost as many cells in subtype 2 as in subtype 1 with a slight predominance in subtype 2. In Figure 2(c), the mean fluorescence intensity of the cell subtypes in the different cell groups was depicted. While the ICAM-1 expression in the incubator control group was stable in both subtypes (2158 ± 234.4 RFU versus 2082 ± 171 RFU), and the μg cell group displayed significantly less expression of ICAM-1 in subtype 1 compared to subtype 2. ICAM-1 expression was significantly reduced in the μg group compared to the 1 g control and the incubator control group. Cells in the 1 g control group exhibited a similar ICAM-1 expression distribution as cells from the μg group. The mean fluorescence intensities between subtype 2 of different groups did not change dramatically, except a significant difference between the 1 g control group and the incubator control group. In summary, we suppose that ICAM-1 expression was downregulated in microglia cells in simulated microgravity.


Regulation of ICAM-1 in cells of the monocyte/macrophage system in microgravity.

Paulsen K, Tauber S, Dumrese C, Bradacs G, Simmet DM, Gölz N, Hauschild S, Raig C, Engeli S, Gutewort A, Hürlimann E, Biskup J, Unverdorben F, Rieder G, Hofmänner D, Mutschler L, Krammer S, Buttron I, Philpot C, Huge A, Lier H, Barz I, Engelmann F, Layer LE, Thiel CS, Ullrich O - Biomed Res Int (2015)

Cytometry analysis of ICAM-1 expression in BV-2 microglial cells in simulated microgravity (2D clinorotation). BV-2 microglial cells were exposed to either clinorotation (μg), placed in the clinostat but not rotated (1 g control group), or cultured under standard cell culture conditions (incubator control) for 24 h. Cells were stained for ICAM-1 surface expression and analyzed by flow cytometry. The level of ICAM-1 surface expression is represented by the mean fluorescent intensity assessed by flow cytometry. (a) In forward/sideward scatter detection mode of flow cytometry, two gates were set to separate two subtypes of BV-2 microglial cells that appeared different in size and granulation (subtypes 1 and 2 in dot plots). (b) Distribution of BV-2 microglial cells in subtypes 1 and 2 after exposure to different gravity conditions. (c) Quantification of ICAM-1 expression after exposure to different gravity conditions within subtypes 1 and 2. Data are given as median ± SE (*P < 0.1, **P < 0.05, ***P < 0.01, n = 3, according to one-way ANOVA followed by Wilcoxon or unpaired t-test).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
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fig2: Cytometry analysis of ICAM-1 expression in BV-2 microglial cells in simulated microgravity (2D clinorotation). BV-2 microglial cells were exposed to either clinorotation (μg), placed in the clinostat but not rotated (1 g control group), or cultured under standard cell culture conditions (incubator control) for 24 h. Cells were stained for ICAM-1 surface expression and analyzed by flow cytometry. The level of ICAM-1 surface expression is represented by the mean fluorescent intensity assessed by flow cytometry. (a) In forward/sideward scatter detection mode of flow cytometry, two gates were set to separate two subtypes of BV-2 microglial cells that appeared different in size and granulation (subtypes 1 and 2 in dot plots). (b) Distribution of BV-2 microglial cells in subtypes 1 and 2 after exposure to different gravity conditions. (c) Quantification of ICAM-1 expression after exposure to different gravity conditions within subtypes 1 and 2. Data are given as median ± SE (*P < 0.1, **P < 0.05, ***P < 0.01, n = 3, according to one-way ANOVA followed by Wilcoxon or unpaired t-test).
Mentions: First, we analyzed ICAM-1 expression in BV-2 microglial cells after 24 h clinorotation (60 rpm, 4 mm pipette diameter, maximal residual acceleration of 4 × 10−3 g at the outer radius of the pipette). The clinostat device was placed in an incubator, which provides constant 37°C. Fifteen serological pipettes rotated at the same time with 60 rpm. 1 g controls were placed at the ground plate of the clinostat without rotation but with the same environment condition like μg samples. A 1 g control group of BV-2 cells was filled into 1 mL serological pipettes in the same way as the clinorotation cell group but was not clinorotated. Another control group was kept at regular cell culture conditions in the incubator (37°C, 5% CO2). Cells were subsequently stained for cell surface ICAM-1, apoptosis (TUNEL), cell delineation (HCS CellMask), and DNA (DAPI) (Figure 2). ICAM-1 expression analysis by flow cytometry revealed two distinct subtypes of cells in the clinorotated group (μg group) compared to the 1 g control group and the incubator control group consisting of only one subtype, respectively (Figure 2(a)). The first of the two subtypes was small and stronger granulated (subtype 1) than the second subtype, which appears taller but less granulated (subtype 2). Apoptotic cells were excluded from the analysis by TUNEL staining. Subtype 1 could possibly represent an activated state. Subtype 1 was found in the μg group as well as in the 1 g control group, whereas the incubator control did virtually not contain this subtype. Subtype 2 was represented in all three cell groups, μg, 1 g control, and incubator control cell group. However, it was primarily present in the μg and in the incubator control group and less present in the 1 g control group. The population distribution within cell groups is illustrated in Figure 2(b), showing the relative cell numbers of each population in each cell group. Since the incubator control group consisted almost exclusively of cells in subtype 2, this number was nearly 100%, whereas subtype 1 was close to 0%. The μg group had almost as many cells in subtype 2 as in subtype 1 with a slight predominance in subtype 2. In Figure 2(c), the mean fluorescence intensity of the cell subtypes in the different cell groups was depicted. While the ICAM-1 expression in the incubator control group was stable in both subtypes (2158 ± 234.4 RFU versus 2082 ± 171 RFU), and the μg cell group displayed significantly less expression of ICAM-1 in subtype 1 compared to subtype 2. ICAM-1 expression was significantly reduced in the μg group compared to the 1 g control and the incubator control group. Cells in the 1 g control group exhibited a similar ICAM-1 expression distribution as cells from the μg group. The mean fluorescence intensities between subtype 2 of different groups did not change dramatically, except a significant difference between the 1 g control group and the incubator control group. In summary, we suppose that ICAM-1 expression was downregulated in microglia cells in simulated microgravity.

Bottom Line: In contrast, ICAM-1 expression increased in macrophage-like differentiated human U937 cells during the microgravity phase of parabolic flights and in long-term microgravity provided by a 2D clinostat or during the orbital SIMBOX/Shenzhou-8 mission.In nondifferentiated U937 cells, no effect of microgravity on ICAM-1 expression could be observed during parabolic flight experiments.Thus, ICAM-1 can be considered as a rapid-reacting and sustained gravity-regulated molecule in mammalian cells.

View Article: PubMed Central - PubMed

Affiliation: Institute of Anatomy, Faculty of Medicine, University of Zurich, Winterthurerstraß 190, 8057 Zurich, Switzerland.

ABSTRACT
Cells of the immune system are highly sensitive to altered gravity, and the monocyte as well as the macrophage function is proven to be impaired under microgravity conditions. In our study, we investigated the surface expression of ICAM-1 protein and expression of ICAM-1 mRNA in cells of the monocyte/macrophage system in microgravity during clinostat, parabolic flight, sounding rocket, and orbital experiments. In murine BV-2 microglial cells, we detected a downregulation of ICAM-1 expression in clinorotation experiments and a rapid and reversible downregulation in the microgravity phase of parabolic flight experiments. In contrast, ICAM-1 expression increased in macrophage-like differentiated human U937 cells during the microgravity phase of parabolic flights and in long-term microgravity provided by a 2D clinostat or during the orbital SIMBOX/Shenzhou-8 mission. In nondifferentiated U937 cells, no effect of microgravity on ICAM-1 expression could be observed during parabolic flight experiments. We conclude that disturbed immune function in microgravity could be a consequence of ICAM-1 modulation in the monocyte/macrophage system, which in turn could have a strong impact on the interaction with T lymphocytes and cell migration. Thus, ICAM-1 can be considered as a rapid-reacting and sustained gravity-regulated molecule in mammalian cells.

Show MeSH
Related in: MedlinePlus