Enhanced self-renewal of human pluripotent stem cells by simulated microgravity

Abstract

A systematic study on the biological effects of simulated microgravity (sµg) on human pluripotent stem cells (hPSC) is still lacking. Here, we used a fast-rotating 2-D clinostat to investigate the sµg effect on proliferation, self-renewal, and cell cycle regulation of hPSCs. We observed significant upregulation of protein translation of pluripotent transcription factors in hPSC cultured in sµg compared to cells cultured in 1g conditions. In addition to a significant increase in expression of telomere elongation genes. Differentiation experiments showed that hPSC cultured in sµg condition were less susceptible to differentiation compared to cells in 1g conditions. These results suggest that sµg enhances hPSC self-renewal. Our study revealed that sµg enhanced the cell proliferation of hPSCs by regulating the expression of cell cycle-associated kinases. RNA-seq analysis indicated that in sµg condition the expression of differentiation and development pathways are downregulated, while multiple components of the ubiquitin proteasome system are upregulated, contributing to an enhanced self-renewal of hPSCs. These effects of sµg were not replicated in human fibroblasts. Taken together, our results highlight pathways and mechanisms in hPSCs vulnerable to microgravity that imposes significant impacts on human health and performance, physiology, and cellular and molecular processes.

Spatio-temporal dynamics enhance cellular diversity, neuronal function and further maturation of human cerebral organoids

“…Thus, organoids exposed to varying magnitudes of hydrodynamic forces are expected to display differences in structural and functional features during development. As such, cell proliferation of hPSCs has been shown to increase under simulated microgravity culture conditions with significantly higher expression levels of Ki-67 compared to 1 g culture condition, leading to enhanced self-renewal, as revealed by the increased protein levels of the core set of pluripotent transcription factors 99 . In another study, human embryonic stem cell (hESC)-derived forebrain-specific neural-cortical organoids were shown to have the highest expression of Ki-67 when cultured under RCCS conditions after day 14 of the generation process compared to organoids cultured in static and other days of the generation in RCCS 31 .…”

EuniceScope: Low-Cost Imaging Platform for Studying Microgravity Cell Biology

“…An appropriate rotational velocity is needed to avoid cells from responding to gravity at low frequencies, and to limit the centrifugal force which introduces mechanical strains artifacts at high frequencies. Rotational speed of around 30–120 rpm is typically utilized for studying small animal samples in an aqueous growth medium [18] , [27] , [28] . Hence, 2 rotational velocities within this range were tested: 35 rpm and 90 rpm.…”

Sex difference in liver diseases: How preclinical models help to dissect the sex-related mechanisms sustaining NAFLD and hepatocellular carcinoma

“… 54 , 55 hiPSC have the advantage that can be obtained from any human somatic cells through the ectopic expression of transcription factors and exhibit unlimited self-renewal ability and ease of accessibility to donor tissues thus enhancing their versatility. 56 , 57 Moreover, HLC exhibit morphology, metabolism, and transcriptome profile similar to those of PHH with the advantage of a reduced functionality drift over cell culture passages, 58 , 59 thus representing an important resource for in vitro human liver disease processes investigation. Despite the aforementioned advantages, the use of HLC is limited by ethical restrictions that are different in different countries or by potential issues related to the lack of a standardized differentiation protocol that could lead to an incomplete hepatic differentiation.…”