Ex vivo Induction of Apoptotic Mesenchymal Stem Cell by High Hydrostatic Pressure

Mechanoactivation of Single Stem Cells in Microgels Using a 3D-Printed Stimulation Device

In this study, the novel 3D-printed pressure chamber for encapsulated single-cell stimulation (3D-PRESS) platform is introduced for the mechanical stimulation of single stem cells in 3D microgels. The custom-designed 3D-PRESS, allows precise pressure application up to 400 kPa at the single-cell level. Microfluidics is employed to encapsulate single mesenchymal stem cells within ionically cross-linked alginate microgels with cell adhesion RGD peptides. Rigorous testing affirms the leak-proof performance of the 3D-PRESS device up to 400 kPa, which is fully biocompatible. 3D-PRESS is implemented on mesenchymal stem cells for mechanotransduction studies, by specifically targeting intracellular calcium signaling and the nuclear translocation of a mechanically sensitive transcription factor. Applying 200 kPa pressure on individually encapsulated stem cells reveals heightened calcium signaling in 3D microgels compared to conventional 2D culture. Similarly, Yes-associated protein (YAP) translocation into the nucleus occurs at 200 kPa in 3D microgels with cell-binding RGD peptides unveiling the involvement of integrin-mediated mechanotransduction in singly encapsulated stem cells in 3D microgels. Combining live-cell imaging with precise mechanical control, the 3D-PRESS platform emerges as a versatile tool for exploring cellular responses to pressure stimuli, applicable to various cell types, providing novel insights into single-cell mechanobiology.

Single cell RNA-sequencing reveals the cellular senescence of placental mesenchymal stem/stromal cell in preeclampsia

INTRODUCTION

Preeclampsia (PE) is a severe obstetric complication closely associated with placental dysfunction. Placental mesenchymal stem/stromal cells (PMSCs) modulate placental development while PE PMSCs are excessively senescent to disturb placental function. Nevertheless, the senescence mechanism of PE PMSCs remains unclear.

METHODS

PE-related single-cell RNA sequencing datasets (GSE173193), data of chip detection (GSE99007) and bulk transcriptome RNA sequencing datasets (GSE75010) were extracted from the GEO database. Firstly, the functional enrichment analyses of the differentially expressed genes (DEGs) in PMSCs were conducted. Then, the clusters of PE PMSCs were distinguished according to the expressions of senescence-related genes (SRGs) by consensus clustering analysis. Cell cycle analysis, senescence β-galactosidase, Transwell, and tube formation were conducted. Next, the expressions of the senescence-associated secretory phenotype (SASPs) were displayed. The characteristic genes of PE were screened by the least absolute shrinkage and selection operator analysis. CTSZ was suppressed in PMSCs and the cellular senescence levels were evaluated.

RESULTS

In this study, The DEGs in PMSCs were closely associated with cellular senescence. The score of SRGs was significantly higher and most of the SASPs were abnormally expressed in the senescent group. Seven characteristic genes of PE were identified, thereinto, CTSZ reduction may accelerate the senescence in PMSCs in vitro.

DISCUSSION

Combined with bioinformatic analysis and lab experiments, our study emphatically revealed the abnormal cellular senescence in PE PMSCs, in which CTSZ, one of the PE characteristic genes, regulated the cellular senescence levels in PMSCs. These findings might help to deepen the understanding of the senescence mechanism of PMSCs in PE.

Apoptotic Extracellular Vesicles Derived from Human Umbilical Vein Endothelial Cells Promote Skin Repair by Enhancing Angiogenesis: From Death to Regeneration

Purpose

The promotion of angiogenesis is an effective strategy for skin wound repair. While the transplantation of endothelial cells has shown promise in vascularization, the underlying mechanism remains unclear. Recent studies have suggested that transplanted cells undergo apoptosis in a short period and release apoptotic extracellular vesicles (ApoEVs) that may have therapeutic potential.

Methods

In this study, we isolated ApoEVs from human umbilical vein endothelial cells (HUVECs) and characterized their properties. In vitro, we assessed the effects of ApoEVs on the proliferation, migration, and differentiation of endothelial cells and fibroblasts. In vivo, we investigated the therapeutic role of ApoEVs-AT in full-thickness skin wounds, evaluating wound closure rate, re-epithelialization, granulation tissue formation, vascularization, scar area, and collagen 3(Col3)/collagen 1(Col 1) ratio.

Results

ApoEVs derived from HUVECs displayed typical characteristics. In vitro, ApoEVs significantly enhanced the proliferation, migration, tube formation, and expression of angiogenic-related genes in endothelial cells and slightly promoted the proliferation and migration of fibroblasts. In vivo, ApoEVs improved the wound closure rate, re-epithelialization, the formation of granulation tissue, and vascularization. Besides, ApoEVs reduced scar formation, accompanied by an increase in the Col 3/ Col 1 ratio.

Conclusion

Given their abundant source and effectiveness, this study provided a novel approach for angiogenesis in tissue regeneration and deepened the understanding of from death to regeneration.

Preparation of Apoptotic Extracellular Vesicles from Adipose Tissue and Their Efficacy in Promoting High-Quality Skin Wound Healing

Purpose

A lot of strategies have been attempted to achieve high-quality skin wound healing, among them, fat transplantation has been used for skin wound repair and scar management and has shown beneficial effects. However, the underlying mechanism is still unclear. Recently, studies found that transplanted cells underwent apoptosis within a short period and apoptotic extracellular vesicles (ApoEVs) might play the therapeutic role.

Methods

In this study, we directly isolated apoptotic extracellular vesicles from adipose tissue (ApoEVs-AT) and evaluated their characteristics. In vivo, we investigated the therapeutic role of ApoEVs-AT in full-thickness skin wounds. The rate of wound healing, the quality of granulation tissue, and the area of scars were evaluated here. In vitro, we investigated the cellular behaviors of fibroblasts and endothelial cells induced by ApoEVs-AT, including cellular uptake, proliferation, migration, and differentiation.

Results

ApoEVs-AT could be successfully isolated from adipose tissue and possessed the basic characteristics of ApoEVs. In vivo, ApoEVs-AT could accelerate skin wound healing, improve the quality of granulation tissue, and reduce the area of scars. In vitro, ApoEVs-AT could be engulfed by fibroblasts and endothelial cells, significantly enhancing their proliferation and migration. Moreover, ApoEVs-AT could promote adipogenic differentiation and inhibit the fibrogenic differentiation of fibroblasts.

Conclusion

These findings indicated that ApoEVs could be successfully prepared from adipose tissue and showed the ability to promote high-quality skin wound healing by modulating fibroblasts and endothelial cells.

Thyroid hormone modulates hyperoxic neonatal lung injury and mitochondrial function

Mitochondrial dysfunction at birth predicts bronchopulmonary dysplasia (BPD) in extremely low-birth weight (ELBW) infants. Recently, nebulized thyroid hormone (TH), given as triiodothyronine (T3), was noted to decrease pulmonary fibrosis in adult animals through improved mitochondrial function. In this study, we tested the hypothesis that TH may have similar effects on hyperoxia-induced neonatal lung injury and mitochondrial dysfunction by testing whether i.n. T3 decreases neonatal hyperoxic lung injury in newborn mice; whether T3 improves mitochondrial function in lung homogenates, neonatal murine lung fibroblasts (NMLFs), and umbilical cord-derived mesenchymal stem cells (UC-MSCs) obtained from ELBW infants; and whether neonatal hypothyroxinemia is associated with BPD in ELBW infants. We found that inhaled T3 (given i.n.) attenuated hyperoxia-induced lung injury and mitochondrial dysfunction in newborn mice. T3 also reduced bioenergetic deficits in UC-MSCs obtained from both infants with no or mild BPD and those with moderate to severe BPD. T3 also increased the content of peroxisome proliferator-activated receptor γ coactivator 1α in lung homogenates of mice exposed to hyperoxia as well as mitochondrial potential in both NMLFs and UC-MSCs. ELBW infants who died or developed moderate to severe BPD had lower total T4 (TT4) compared with survivors with no or mild BPD. In conclusion, TH signaling and function may play a critical role in neonatal lung injury, and inhaled T3 supplementation may be useful as a therapeutic strategy for BPD.

Human umbilical cord mesenchymal stromal cells promotes the proliferation and osteogenic differentiation of autologous bone marrow stem cells by secreting exosomes

Fractures are frequently encountered diseases troubling the senior population, and the research on fracture repair and the exploration of effective treatment methods are of great significance. This study aimed to clarify the effect of human umbilical cord mesenchymal stromal cell-derived extracellular vesicles (hUMSC-EVs) on the proliferation and osteogenic differentiation of autologous bone marrow stem cells (ABMSCs). The two kinds of cells were co-cultured firstly, 5-Ethynyl-2'- deoxyuridine (EDU) staining and alizarin red staining were used to detect the proliferation and osteogenic differentiation of ABMSCs. The exosomes of hUMSCs were subsequently extracted to process ABMSCs to further test the effect on the cells. The EDU positive rate of ABMSCs and Collagen II expression were elevated, whereas the TdT-mediated dUTP nick end labeling (TUNEL) positive rate and Matrix Metallopeptidase 13 (MMP13) were markedly decreased after the co-culture of hUMSCs and ABMSCs using Transwell chamber assays. The results indicated that hUMSCs could increase the proliferation of ABMSCs, reduce apoptosis, and promote matrix metabolism. The hUMSCs exosomes were separated and added to ABMSCs. As the exosomes content increased, the proliferation of ABMSCs increased simultaneously, and ABMSCs apoptosis decreased. Meanwhile, ABMSCs that migrated to the submembrane increased compared with untreated ABMSCs. Western blot, qPCR and immunofluorescence results revealed that increased exosomes contents promoted the expression of ABMSCs anabolic-related indicators gradually, while decreased the expression of catabolism-related indicators gradually. The previously described results indicated that hUMSCs promoted the proliferation and osteogenic differentiation of ABMSCs by secreting exosomes.

Adaptive Control of Nanomotor Swarms for Magnetic-Field-Programmed Cancer Cell Destruction

Magnetic nanomotors (MNMs), powered by a magnetic field, are ideal platforms to achieve versatile biomedical applications in a collective and spatiotemporal fashion. Although the programmable swarm of MNMs that mimics the highly ordered behaviors of living creatures has been extensively studied at the microscale, it is of vital importance to manipulate MNM swarms at the nanoscale for on-demand tasks at the cellular level. In this work, a Cy5-tagged caspase-3-specific peptide-modified MNM is designed, and the adaptive control behaviors of MNM swarms are revealed in lysosomes to induce the cancer cell apoptosis under a rotating magnetic field (RMF). A magneto-programmed vortex is predicted to occur with swarms under RMF by the finite element method model and verified in vitro. According to the dynamic model and numerical simulation, the critical rotating frequency under which MNMs are out of step is strongly correlated to their assembling and swarming properties. The adaptivity of swarms maximizes the synchronous rotation to achieve an optimal energy conversion rate. The frequency-adapted controllability of MNM swarms for cancer cell apoptosis is observed in real time in vitro and in vivo. This work provides theoretical and experimental insights to adaptively control MNM swarms for cancer treatment.