Browse
Submit Data
Databases
API
Help

Dataset Information

11 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Simulated Microgravity Inhibits the Proliferation of Chang Liver Cells by Attenuation of the Major Cell Cycle Regulators and Cytoskeletal Proteins.

ABSTRACT: Simulated microgravity (SMG) induced the changes in cell proliferation and cytoskeleton organization, which plays an important factor in various cellular processes. The inhibition in cell cycle progression has been considered to be one of the main causes of proliferation inhibition in cells under SMG, but their mechanisms are still not fully understood. This study aimed to evaluate the effects of SMG on the proliferative ability and cytoskeleton changes of Chang Liver Cells (CCL-13). CCL-13 cells were induced SMG by 3D clinostat for 72 h, while the control group were treated in normal gravity at the same time. The results showed that SMG reduced CCL-13 cell proliferation by an increase in the number of CCL-13 cells in G0/G1 phase. This cell cycle phase arrest of CCL-13 cells was due to a downregulation of cell cycle-related proteins, such as cyclin A1 and A2, cyclin D1, and cyclin-dependent kinase 6 (Cdk6). SMG-exposed CCL-13 cells also exhibited a downregulation of α-tubulin 3 and β-actin which induced the cytoskeleton reorganization. These results suggested that the inhibited proliferation of SMG-exposed CCL-13 cells could be associate with the attenuation of major cell cycle regulators and main cytoskeletal proteins.

SUBMITTER: Ho CNQ

PROVIDER: S-EPMC8123698 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Upregulation of miR-223 in the rat liver inhibits proliferation of hepatocytes under simulated microgravity.

Project description:Long-term spaceflight affects numerous organ systems in the body, including metabolic dysfunction. Recently, ample evidence has demonstrated that the liver is a vulnerable organ during spaceflight. However, the changes in hepatocyte proliferation and cell cycle control under microgravity remain largely unexplored. In the present study, we first confirmed that the serum levels of aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase, biochemical markers of liver function, were altered in rats under tail suspension (TS) conditions to simulate microgravity, as shown in previous reports. Next, we demonstrated that the cell proliferation activity, determined by Ki67, PCNA and PH3, was significantly decreased at the different TS time points (TS for 14, 28 and 42 days) compared with that in the control group. Consistently, the positive cell cycle regulators Ccna2, Ccnd1, Cdk1, Cdk2 and cyclin D3 were also significantly decreased in the TS groups as shown by quantitative real-time PCR and western blotting analysis. Subsequent analysis revealed that the aberrant hepatocyte proliferation inhibition under simulated microgravity was associated with the upregulation of miR-223 in the liver. We further found that miR-223 inhibited the proliferation of Hepa1-6 cells and identified CDK2 and CUL1 as its direct targets. In addition, the decreased expression of CDK2 and CUL1 was negatively correlated with the level of p27 in vitro and in vivo, which may have been responsible for retarding hepatocyte proliferation. Collectively, these data indicate that upregulation of miR-223 was associated with the inhibition of liver cell growth and reveal the role of miR-223 in rat hepatocyte proliferation disorders and the pathophysiological process under simulated microgravity.

| S-EPMC5519018 | biostudies-literature

Dexamethasone Inhibits Spheroid Formation of Thyroid Cancer Cells Exposed to Simulated Microgravity.

Project description:Detachment and the formation of spheroids under microgravity conditions can be observed with various types of intrinsically adherent human cells. In particular, for cancer cells this process mimics metastasis and may provide insights into cancer biology and progression that can be used to identify new drug/target combinations for future therapies. By using the synthetic glucocorticoid dexamethasone (DEX), we were able to suppress spheroid formation in a culture of follicular thyroid cancer (FTC)-133 cells that were exposed to altered gravity conditions on a random positioning machine. DEX inhibited the growth of three-dimensional cell aggregates in a dose-dependent manner. In the first approach, we analyzed the expression of several factors that are known to be involved in key processes of cancer progression such as autocrine signaling, proliferation, epithelial-mesenchymal transition, and anoikis. Wnt/?-catenin signaling and expression patterns of important genes in cancer cell growth and survival, which were further suggested to play a role in three-dimensional aggregation, such as NFKB2, VEGFA, CTGF, CAV1, BCL2(L1), or SNAI1, were clearly affected by DEX. Our data suggest the presence of a more complex regulation network of tumor spheroid formation involving additional signal pathways or individual key players that are also influenced by DEX.

| S-EPMC7072698 | biostudies-literature

miRNA-132-3p inhibits osteoblast differentiation by targeting Ep300 in simulated microgravity.

Project description:Recent studies have demonstrated that miRNAs can play important roles in osteoblast differentiation and bone formation. However, the function of miRNAs in bone loss induced by microgravity remains unclear. In this study, we investigated the differentially expressed miRNAs in both the femur tissues of hindlimb unloading rats and primary rat osteoblasts (prOB) exposed to simulated microgravity. Specifically, miR-132-3p was found up-regulated and negatively correlated with osteoblast differentiation. Overexpression of miR-132-3p significantly inhibited prOB differentiation, whereas inhibition of miR-132-3p function yielded an opposite effect. Furthermore, silencing of miR-132-3p expression effectively attenuated the negative effects of simulated microgravity on prOB differentiation. Further experiments confirmed that E1A binding protein p300 (Ep300), a type of histone acetyltransferase important for Runx2 activity and stability, was a direct target of miR-132-3p. Up-regulation of miR-132-3p by simulated microgravity could inhibit osteoblast differentiation in part by decreasing Ep300 protein expression, which, in turn, resulted in suppression of the activity and acetylation of Runx2, a key regulatory factor of osteoblast differentiation. Taken together, our findings are the first to demonstrate that miR-132-3p can inhibit osteoblast differentiation and participate in the regulation of bone loss induced by simulated microgravity, suggesting a potential target for counteracting decreases in bone formation.

| S-EPMC4685444 | biostudies-literature

Simulated microgravity inhibits C2C12 myogenesis via phospholipase D2-induced Akt/FOXO1 regulation.

Project description:The skeletal muscle system has evolved to maintain body posture against a constant gravitational load. Mammalian target of rapamycin (mTOR) regulates the mechanically induced increase in the skeletal muscle mass. In the present study, we investigated mTOR pathway in C2C12 myoblasts in a model of mechanical unloading by creating a simulated microgravity (SM) using 3 D clinorotation. SM decreased the phosphorylation of Akt at Ser 473, which was mediated by mTOR complex 2 (mTORC2), in C2C12 myoblasts, leading to a decrease in the cell growth rate. Subsequently, SM inhibited C2C12 myogenesis in an Akt-dependent manner. In addition, SM increased the phospholipase D (PLD) activity by enhancing PLD2 expression, resulting in the dissociation of mSIN1 from the mTORC2, followed by decrease in the phosphorylation of Akt at Ser 473, and FOXO1 at Ser 256 in C2C12 myoblasts. Exposure to SM decreased the autophagic flux of C2C12 myoblasts by regulation of mRNA level of autophagic genes in a PLD2 and FOXO1-dependent manner, subsequently, resulting in a decrease in the C2C12 myogenesis. In conclusion, by analyzing the molecular signature of C2C12 myogenesis using SM, we suggest that the regulatory axis of the PLD2 induced Akt/FOXO1, is critical for C2C12 myogenesis.

| S-EPMC6797799 | biostudies-literature

miR-181c-5p mediates simulated microgravity-induced impaired osteoblast proliferation by promoting cell cycle arrested in the G<sub>2</sub> phase.

Project description:Impaired osteoblast proliferation plays fundamental roles in microgravity-induced bone loss, and cell cycle imbalance may result in abnormal osteoblast proliferation. However, whether microgravity exerts an influence on the cell cycle in osteoblasts or what mechanisms may underlie such an effect remains to be fully elucidated. Herein, we confirmed that simulated microgravity inhibits osteoblast proliferation. Then, we investigated the effect of mechanical unloading on the osteoblast cell cycle and found that simulated microgravity arrested the osteoblast cell cycle in the G2 phase. In addition, our data showed that cell cycle arrest in osteoblasts from simulated microgravity was mainly because of decreased cyclin B1 expression. Furthermore, miR-181c-5p directly inhibited cyclin B1 protein translation by binding to a target site in the 3'UTR. Lastly, we demonstrated that inhibition of miR-181c-5p partially counteracted cell cycle arrest and decreased the osteoblast proliferation induced by simulated microgravity. In conclusion, our study demonstrates that simulated microgravity inhibits cell proliferation and induces cell cycle arrest in the G2 phase in primary mouse osteoblasts partially through the miR-181c-5p/cyclin B1 pathway. This work may provide a novel mechanism of microgravity-induced detrimental effects on osteoblasts and offer a new avenue to further investigate bone loss induced by mechanical unloading.

| S-EPMC6484313 | biostudies-literature

static vs simulated microgravity

Project description:The below table includes a smaller list of data that was analyzed by dChip and filtered by pvalue such that a file with about 4600 genes was obtained, which allowed for ease of use from 40,000 genes. Keywords: static vs simulated microgravity

2006-12-31 | GSE4658 | GEO

Simulated Microgravity Inhibits Differentiation and Alters Gene Expression Profiles of 2T3 Pre-osteoblasts

Project description:Exposure to microgravity causes bone loss in humans, and the underlying mechanism is believed to be at least partially due to a decrease in bone formation by osteoblasts. Here, we examined the hypothesis that microgravity changes osteoblast gene expression profiles, resulting in bone loss. For this study, we developed an in vitro system that simulates microgravity using the Random Positioning Machine (RPM) to study the effects of microgravity on 2T3 pre-osteoblast cells grown in gas-permeable culture disks. Exposure of 2T3 cells to simulated microgravity using RPM for up to 9 days significantly inhibited alkaline phosphatase activity, recapitulating an expected bone loss response, without altering cell proliferation and shape. Next, we carried out a DNA microarray analysis to determine the gene expression profile of 2T3 cells exposed to 3 days of simulated microgravity. Among 10,000 genes examined with the microarray, 88 were downregulated while 52 were upregulated significantly by simulated microgravity by more than two-fold in comparison to the static 1g condition. By using real-time PCR assays, we verified the microarray data using some of the expected genes. For example, we confirmed that microgravity induced downregulation of alkaline phosphatase, runt related transcription factor 2 (runx2), osteomodulin, and parathyroid hormone 1 receptor, while confirming upregulation of cathepsin K mRNAs. In addition to the changes of the expected genes, the microarray data identified many more genes. The identification of these gravisensitive genes provide an useful insight in generating further hypotheses regarding their roles not only in microgravity-induced bone loss, but also in general population of patients with similar pathologic conditions such as osteoporosis. Keywords: other

2004-05-07 | GSE1367 | GEO

Cytoskeletal Remodeling Mimics Endothelial Response to Microgravity.

Project description:Mechanical cues contribute to the maintenance of a healthy endothelium, which is essential for vascular integrity. Indeed endothelial cells are mechanosensors that integrate the forces in the form of biochemical signals. The cytoskeleton is fundamental in sensing mechanical stimuli and activating specific signaling pathways. Because the cytoskeleton is very rapidly remodeled in endothelial cells exposed to microgravity, we investigated whether the disruption of actin polymerization by cytochalasin D in 1g condition triggers and orchestrates responses similar to those occurring in micro- and macro-vascular endothelial cells upon gravitational unloading. We focused our attention on the effect of simulated microgravity on stress proteins and transient receptor potential melastatin 7 (TRPM7), a cation channel that acts as a mechanosensor and modulates endothelial cell proliferation and stress response. Simulated microgravity downregulates TRPM7 in both cell types. However, 24 h of treatment with cytochalasin D decreases the amounts of TRPM7 only in macrovascular endothelial cells, suggesting that the regulation and the role of TRPM7 in microvascular cells are more complex than expected. The 24 h culture in the presence of cytochalasin D mimics the effect of simulated microgravity in modulating stress response in micro- and macro-vascular endothelial cells. We conclude that cytoskeletal disruption might mediate some effects of microgravity in endothelial cells.

| S-EPMC8458731 | biostudies-literature

Recovery of stem cell proliferation by low intensity vibration under simulated microgravity requires LINC complex.

Project description:Mesenchymal stem cells (MSC) rely on their ability to integrate physical and spatial signals at load bearing sites to replace and renew musculoskeletal tissues. Designed to mimic unloading experienced during spaceflight, preclinical unloading and simulated microgravity models show that alteration of gravitational loading limits proliferative activity of stem cells. Emerging evidence indicates that this loss of proliferation may be linked to loss of cellular cytoskeleton and contractility. Low intensity vibration (LIV) is an exercise mimetic that promotes proliferation and differentiation of MSCs by enhancing cell structure. Here, we asked whether application of LIV could restore the reduced proliferative capacity seen in MSCs that are subjected to simulated microgravity. We found that simulated microgravity (sMG) decreased cell proliferation and simultaneously compromised cell structure. These changes included increased nuclear height, disorganized apical F-actin structure, reduced expression, and protein levels of nuclear lamina elements LaminA/C LaminB1 as well as linker of nucleoskeleton and cytoskeleton (LINC) complex elements Sun-2 and Nesprin-2. Application of LIV restored cell proliferation and nuclear proteins LaminA/C and Sun-2. An intact LINC function was required for LIV effect; disabling LINC functionality via co-depletion of Sun-1, and Sun-2 prevented rescue of cell proliferation by LIV. Our findings show that sMG alters nuclear structure and leads to decreased cell proliferation, but does not diminish LINC complex mediated mechanosensitivity, suggesting LIV as a potential candidate to combat sMG-induced proliferation loss.

| S-EPMC6520402 | biostudies-literature