Partial Reprogramming Exerts a Rejuvenating Effect on Human Mesenchymal Stem Cells That Underwent Replicative Senescence in Culture.

Mesenchymal stem/stromal cells (MSCs) are becoming increasingly important for biomedical applications, such as cell therapy, disease modeling, and drug screening. At the same time, long-term cultivation, which is necessary to prepare a sufficient amount of cellular material for therapeutic and research purposes, is accompanied by the development of replicative senescence. Partial reprogramming emerged as a novel method that shows promising results in the rejuvenation of cells in vitro and in vivo; however, it has not yet been applied for human MSCs that have undergone replicative senescence in culture.

Long-Term Cryopreservation May Cause Genomic Instability and the Premature Senescence of Cells.

Cryopreservation is an essential step for utilizing various cell types for biological research and medical purposes. At the same time, there is a lack of data on the effect of cryopreservation, especially when prolonged, on the karyotype of cells. In the present work, we analyzed the genetic stability of cells subjected to a cryopreservation procedure.

HyPer as a tool to determine the reductive activity in cellular compartments.

A multitude of cellular metabolic and regulatory processes rely on controlled thiol reduction and oxidation mechanisms. Due to our aerobic environment, research preferentially focuses on oxidation processes, leading to limited tools tailored for investigating cellular reduction. Here, we advocate for repurposing HyPer1, initially designed as a fluorescent probe for HO levels, as a tool to measure the reductive power in various cellular compartments.

Mesenchymal Stem/Stromal Cells in Three-Dimensional Cell Culture: Ion Homeostasis and Ouabain-Induced Apoptosis.

This study describes the changes in ion homeostasis of human endometrial mesenchymal stem/stromal cells (eMSCs) during the formation of three-dimensional (3D) cell structures (spheroids) and investigates the conditions for apoptosis induction in 3D eMSCs. Detached from the monolayer culture, (2D) eMSCs accumulate Na and have dissipated transmembrane ion gradients, while in compact spheroids, eMSCs restore the lower Na content and the high K/Na ratio characteristic of functionally active cells. Organized as spheroids, eMSCs are non-proliferating cells with an active Na/K pump and a lower K content per g cell protein, which is typical for quiescent cells and a mean lower water content (lower hydration) in 3D eMSCs.

Inhibition of thioredoxin reductase activity reduces the antioxidant defense capacity of human pluripotent stem cells under conditions of mild but not severe oxidative stress.

Pro-oxidative shift in redox balance, usually termed as "oxidative stress", can lead to different cell responses depending on its intensity. Excessive accumulation of reactive oxygen species ("oxidative distress") can cause DNA, lipid and protein damage. Physiological oxidative stimulus ("oxidative eustress"), in turn, can favor cell proliferation and differentiation - the processes of paramount importance primarily for stem cells.

Store-Operated Ca Entry Contributes to Piezo1-Induced Ca Increase in Human Endometrial Stem Cells.

Endometrial mesenchymal stem cells (eMSCs) are a specific class of stromal cells which have the capability to migrate, develop and differentiate into different types of cells such as adipocytes, osteocytes or chondrocytes. It is this unique plasticity that makes the eMSCs significant for cellular therapy and regenerative medicine. Stem cells choose their way of development by analyzing the extracellular and intracellular signals generated by a mechanical force from the microenvironment.

Resistance to HO-induced oxidative stress in human cells of different phenotypes.

Application of genetically encoded biosensors of redox-active compounds promotes the elaboration of new methods for investigation of intracellular redox activities. Previously, we have developed a method to measure quantitatively the intracellular concentration of hydrogen peroxide (HO) in living cells using genetically encoded biosensor HyPer. In the present study, we refined the method and applied it for comparing the antioxidant system potency in human cells of different phenotypes by measuring the gradient between the extracellular and cytoplasmic HO concentrations under conditions of HO-induced external oxidative stress.

Induction of Premature Cell Senescence Stimulated by High Doses of Antioxidants Is Mediated by Endoplasmic Reticulum Stress.

In our previous study, we found that high doses of several substances with antioxidant capacities (Tempol, resveratrol, diphenyleneiodonium) can cause genotoxic stress and induce premature senescence in the human mesenchymal stem cells (MSCs). Here, using whole-transcriptome analysis, we revealed the signs of endoplasmic reticulum stress and unfolded protein response (UPR) in MSCs stressed with Tempol and resveratrol. In addition, we found the upregulation of genes, coding the UPR downstream target APC/C, and E3 ubiquitin ligase that regulate the stability of cell cycle proteins.

Cell cycle-coupled changes in the level of reactive oxygen species support the proliferation of human pluripotent stem cells.

The study of proliferation regulation in human pluripotent stem cells is crucial to gain insights into understanding the physiology of these cells. However, redox regulation of the pluripotent cell cycle remains largely unexplored. Here, using human embryonic stem cells (hESCs) as well as human induced pluripotent stem cells (hiPSCs), we demonstrate that the level of reactive oxygen species (ROS) in pluripotent cells oscillates in accordance with the cell cycle progression with the peak occurring at transition from S to G /M phase of the cycle.

Effects of IGFBP3 knockdown on human endometrial mesenchymal stromal cells stress-induced senescence.

Insulin-like growth factor binding protein 3 (IGFBP3) is known for its pleiotropic ability to regulate various cellular processes such as proliferation, apoptosis, differentiation etc. It has recently been shown that IGFBP3 is part of the secretome of senescent human endometrial mesenchymal stromal cells (MESCs) (Griukova et al., 2019) that takes part in paracrine propagation of senescence-like phenotype in MESCs (Vassilieva et al.

Three-Dimensional Compaction Switches Stress Response Programs and Enhances Therapeutic Efficacy of Endometrial Mesenchymal Stem/Stromal Cells.

Mesenchymal stem cells are currently tested as a promising tool for the treatment of a wide range of human diseases. Enhanced therapeutic potential of spheroids formed from these cells has been proved in numerous studies, however, the fundamental basics of this effect are still being discussed. In this work, we showed that endometrial mesenchymal stem/stromal cells (eMSCs) assembled in spheroids possess a higher therapeutic efficacy compared to cells grown in monolayer in the treatment of the defects that are non-specific for eMSC tissue origin - skin wounds.

Local calcium signalling is mediated by mechanosensitive ion channels in mesenchymal stem cells.

Mechanical forces are implicated in key physiological processes in stem cells, including proliferation, differentiation and lineage switching. To date, there is an evident lack of understanding of how external mechanical cues are coupled with calcium signalling in stem cells. Mechanical reactions are of particular interest in adult mesenchymal stem cells because of their promising potential for use in tissue remodelling and clinical therapy.