Capacity Of Stem Cells Research Articles

Ursolic acid incorporated nanofibers improves chondrogenic differentiation of mesenchymal stem cells

AbstractCartilage injuries and osteoarthritis are among the most common problems of the elderly in the world, and common treatments are limited to relieving pain. Today, tissue‐engineering is one of the most important hopes of finding a cure to overcome these problems. Therefore, the present study aimed to examine the potential impact of Ursolic acid (UA) blended with electrospun nanofibrous scaffolds fabricated by polycaprolactone (PCL) and poly(L‐lactic acid) (PLLA) on the chondrogenesis capacity of the mesenchymal stem cells (MSCs). Characterization results of the scaffolds revealed that the hydrophilicity and biocompatibility of the PCL‐PLLA nanofibers increased significantly and therefore MSCs attachment and proliferation improved in comparison with empty nanofibers. In addition, differentiation evaluation was also indicated that the expression level of chondrogenic‐related genes was increased significantly in MSCs differentiated on the PCL‐PLLA‐UA nanofibers compared to the differentiated cells on the PCL‐PLLA nanofibers. Alcian blue staining was also revealed that glycosaminoglycans production was amplified significantly in the cells differentiated on the PCL‐PLLA‐UA nanofibers. Fibronectin protein expression that is an important pre‐cartilage condensation marker was also increased in MSCs differentiated on the UA containing scaffold. In summary, the results indicated a significant improvement in the chondrogenic differentiation potential of the MSCs when differentiated on the PCL‐PLLA‐UA nanofibers. It can be concluded that this cell‐scaffold combination can be suggested as potential candidate for cartilage tissue‐engineering applications.

Identification of Quiescent LGR5+ Stem Cells in the Human Colon

In the mouse intestinal epithelium, Lgr5+ stem cells are vulnerable to injury, owing to their predominantly cycling nature, and their progenies de-differentiate to replenish the stem cell pool. However, how human colonic stem cells behave in homeostasis and during regeneration remains unknown. Transcriptional heterogeneity among colonic epithelial cells was analyzed by means of single-cell RNA sequencing analysis of human and mouse colonic epithelial cells. To trace the fate of human colonic stem or differentiated cells, we generated LGR5-tdTomato, LGR5-iCasase9-tdTomato, LGR5-split-Cre, and KRT20-ERCreER knock-in human colon organoids via genome engineering. p27+ dormant cells were further visualized with the p27-mVenus reporter. To analyze the dynamics of human colonic stem cells invivo, we orthotopically xenotransplanted fluorescence-labeled human colon organoids into immune-deficient mice. The cell cycle dynamics in xenograft cells were evaluated using 5-ethynyl-2'-deoxyuridine pulse-chase analysis. The clonogenic capacity of slow-cycling human stem cells or differentiated cells was analyzed in the context of homeostasis, LGR5 ablation, and 5-fluorouracil-induced mucosal injury. Single-cell RNA sequencing analysis illuminated the presence of nondividing LGR5+ stem cells in the human colon. Visualization and lineage tracing of slow-cycling LGR5+p27+ cells and orthotopic xenotransplantation validated their homeostatic lineage-forming capability invivo, which was augmented by 5-FU-induced mucosal damage. Transforming growth factor-β signaling regulated the quiescent state of LGR5+ cells. Despite the plasticity of differentiated KRT20+ cells, they did not display clonal growth after 5-FU-induced injury, suggesting that occupation of the niche environment by LGR5+p27+ cells prevented neighboring differentiated cells from de-differentiating. Our results highlight the quiescent nature of human LGR5+ colonic stem cells and their contribution to post-injury regeneration.

Fibroblasts in intestinal homeostasis, damage, and repair.

The mammalian intestine is a self-renewing tissue that ensures nutrient absorption while acting as a barrier against environmental insults. This is achieved by mature intestinal epithelial cells, the renewing capacity of intestinal stem cells at the base of the crypts, the development of immune tolerance, and the regulatory functions of stromal cells. Upon intestinal injury or inflammation, this tightly regulated mucosal homeostasis is disrupted and is followed by a series of events that lead to tissue repair and the restoration of organ function. It is now well established that fibroblasts play significant roles both in the maintenance of epithelial and immune homeostasis in the intestine and the response to tissue damage mainly through the secretion of a variety of soluble mediators and ligands and the remodeling of the extracellular matrix. In addition, recent advances in single-cell transcriptomics have revealed an unexpected heterogeneity of fibroblasts that comprise distinct cell subsets in normal and inflammatory conditions, indicative of diverse functions. However, there is still little consensus on the number, terminology, and functional properties of these subsets. Moreover, it is still unclear how individual fibroblast subsets can regulate intestinal repair processes and what is their impact on the pathogenesis of inflammatory bowel disease. In this mini-review, we aim to provide a concise overview of recent advances in the field, that we believe will help clarify current concepts on fibroblast heterogeneity and functions and advance our understanding of the contribution of fibroblasts in intestinal damage and repair.

Inhibition of the Phospholipase Cε-c-Jun N-Terminal Kinase Axis Suppresses Glioma Stem Cell Properties.

Glioma stem cells (GSCs), the cancer stem cells of glioblastoma multiforme (GBM), contribute to the malignancy of GBM due to their resistance to therapy and tumorigenic potential; therefore, the development of GSC-targeted therapies is urgently needed to improve the poor prognosis of GBM patients. The molecular mechanisms maintaining GSCs need to be elucidated in more detail for the development of GSC-targeted therapy. In comparison with patient-derived GSCs and their differentiated counterparts, we herein demonstrated for the first time that phospholipase C (PLC)ε was highly expressed in GSCs, in contrast to other PLC isoforms. A broad-spectrum PLC inhibitor suppressed the viability of GSCs, but not their stemness. Nevertheless, the knockdown of PLCε suppressed the survival of GSCs and induced cell death. The stem cell capacity of residual viable cells was also suppressed. Moreover, the survival of mice that were transplanted with PLCε knockdown-GSCs was longer than the control group. PLCε maintained the stemness of GSCs via the activation of JNK. The present study demonstrated for the first time that PLCε plays a critical role in maintaining the survival, stemness, and tumor initiation capacity of GSCs. Our study suggested that PLCε is a promising anti-GSC therapeutic target.

PFKFB3-mediated glycometabolism reprogramming modulates endothelial differentiation and angiogenic capacity of placenta-derived mesenchymal stem cells

BackgroundMesenchymal stem cells (MSCs) have a great potential ability for endothelial differentiation, contributing to an effective means of therapeutic angiogenesis. Placenta-derived mesenchymal stem cells (PMSCs) have gradually attracted attention, while the endothelial differentiation has not been fully evaluated in PMSCs. Metabolism homeostasis plays an important role in stem cell differentiation, but less is known about the glycometabolic reprogramming during the PMSCs endothelial differentiation. Hence, it is critical to investigate the potential role of glycometabolism reprogramming in mediating PMSCs endothelial differentiation.MethodsDil-Ac-LDL uptake assay, flow cytometry, and immunofluorescence were all to verify the endothelial differentiation in PMSCs. Seahorse XF Extracellular Flux Analyzers, Mito-tracker red staining, Mitochondrial membrane potential (MMP), lactate secretion assay, and transcriptome approach were to assess the variation of mitochondrial respiration and glycolysis during the PMSCs endothelial differentiation. Glycolysis enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) was considered a potential modulator for endothelial differentiation in PMSCs by small interfering RNA. Furthermore, transwell, in vitro Matrigel tube formation, and in vivo Matrigel plug assays were performed to evaluate the effect of PFKFB3-induced glycolysis on angiogenic capacities in this process.ResultsPMSCs possessed the superior potential of endothelial differentiation, in which the glycometabolic preference for glycolysis was confirmed. Moreover, PFKFB3-induced glycometabolism reprogramming could modulate the endothelial differentiation and angiogenic abilities of PMSCs.ConclusionsOur results revealed that PFKFB3-mediated glycolysis is important for endothelial differentiation and angiogenesis in PMSCs. Our understanding of cellular glycometabolism and its regulatory effects on endothelial differentiation may propose and improve PMSCs as a putative strategy for clinical therapeutic angiogenesis.

An Appearance Data‐Driven Model Visualizes Cell State and Predicts Mesenchymal Stem Cell Regenerative Capacity (Small Methods 8/2022)

Inside Front Cover In article number 2200087, Cao, Yang, Kou, and co-workers constructed an appearance data-driven mathematical model that excavates four optimal fitted indices, including nucleus roundness, nucleus/cytoplasm ratio, side-scatter height, and ERK1/2 to evaluate the regenerative capacity of mesenchymal stem cells (MSCs) in vitro. This work provides a potential approach to quantify MSCs' capability in basic and translational studies.

Effect of astragaloside IV on the immunoregulatory function of adipose-derived mesenchymal stem cells from patients with psoriasis vulgaris.

To compare the phenotype and adipogenic and osteogenic differentiation capacities of adipose-derived mesenchymal stem cells (AMSCs) isolated from patients with psoriasis vulgaris and healthy donors, and to explore the effects of astragaloside IV, a Traditional Chinese Medicine, on the immunoregulatory function of AMSCs. AMSCs were isolated from human adipose tissue and cultured for three generations in vitro. Cell phenotype and cell cycle analysis were performed by flow cytometry. Adipogenic and osteogenic differentiation of AMSCs was examined by lipid (oil red O) and alkaline phosphatase staining, respectively. Expression of inflammatory mediators was examined by real-time quantitative polymerase chain reaction analysis, and proliferation was quantified using the cell counting kit-8 assay. Expression of CD29, CD44, and CD73 was higher in AMSCs from healthy donors than psoriasis patients, while the reverse was true for expression of CD45, CD31, and HLA-DR. AMSCs from psoriasis patients had a greater ability to undergo adipogenic differentiation than cells from healthy donors, whereas there was no significant difference in osteogenic differentiation between AMSCs from the two sources. Compared with AMSCs from healthy donors, psoriasis patient-derived AMSCs expressed lower levels of the anti-inflammatory cytokines interleukin-10 and trans-forming growth factor-β (TGF-β) and the immune checkpoint ligand programmed cell death 1 ligand 1 (PD-L1) (P < 0.05) and higher levels of the pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ). Incubation of AMSCs from psoriasis patients with astragaloside IV had no significant effect on pro-liferation but increased the expression of TGF-β and PD-L1 and decreased the expression of IFN-γ and TNF-α. AMSCs from patients with psoriasis vulgaris display abnormal proliferation and adipogenesis and an enhanced pro-inflammatory phenotype. These defects were normalized by treatment with astragaloside IV, suggesting that this Traditional Chinese Medicine may be useful for restoring the immunoregulatory function of AMSCs and immune homeostasis in patients with psoriasis vulgaris.

The Interaction between DNMT1 and High-Mannose CD133 Maintains the Slow-Cycling State and Tumorigenic Potential of Glioma Stem Cell.

The quiescent/slow‐cycling state preserves the self‐renewal capacity of cancer stem cells (CSCs) and leads to the therapy resistance of CSCs. The mechanisms maintaining CSCs quiescence remain largely unknown. Here, it is demonstrated that lower expression of MAN1A1 in glioma stem cell (GSC) resulted in the formation of high‐mannose type N‐glycan on CD133. Furthermore, the high‐mannose type N‐glycan of CD133 is necessary for its interaction with DNMT1. Activation of p21 and p27 by the CD133–DNMT1 interaction maintains the slow‐cycling state of GSC, and promotes chemotherapy resistance and tumorigenesis of GSCs. Elimination of the CD133–DNMT1 interaction by a cell‐penetrating peptide or MAN1A1 overexpression inhibits the tumorigenesis of GSCs and increases the sensitivity of GSCs to temozolomide. Analysis of glioma samples reveals that the levels of high‐mannose type N‐glycan are correlated with glioma recurrence. Collectively, the high mannose CD133–DNMT1 interaction maintains the slow‐cycling state and tumorigenic potential of GSC, providing a potential strategy to eliminate quiescent GSCs.

Aerobic training increases mitochondrial respiratory capacity in human skeletal muscle stem cells from sedentary individuals.

The impact of aerobic training on human skeletal muscle cell (HSkMC) mitochondrial metabolism is a significant research gap, critical to understanding the mechanisms by which exercise augments skeletal muscle metabolism. We therefore assessed mitochondrial content and capacity in fully differentiated CD56+ HSkMCs from lean active (LA) and sedentary individuals with obesity (OS) at baseline, as well as lean/overweight sedentary individuals (LOS) at baseline and following an 18-day aerobic training intervention. Participants had in vivo skeletal muscle PCr recovery rate by 31P-MRS (mitochondrial oxidative kinetics) and cardiorespiratory fitness (V̇o2max) assessed at baseline. Biopsies of the vastus lateralis were performed for the isolation of skeletal muscle stem cells. LOS individuals repeated all assessments posttraining. HSkMCs were evaluated for mitochondrial respiratory capacity by high-resolution respirometry. Data were normalized to two indices of mitochondrial content (CS activity and OXPHOS protein expression) and a marker of total cell count (quantity of DNA). LA individuals had significantly higher V̇o2max than OS and LOS-Pre training; however, no differences were observed in skeletal muscle mitochondrial capacity, nor in carbohydrate- or fatty acid-supported HSkMC respiratory capacity. Aerobic training robustly increased in vivo skeletal muscle mitochondrial capacity of LOS individuals, as well as carbohydrate-supported HSkMC respiratory capacity. Indices of mitochondrial content and total cell count were similar among the groups and did not change with aerobic training. Our findings demonstrate that bioenergetic changes induced with aerobic training in skeletal muscle in vivo are retained in HSkMCs in vitro without impacting mitochondrial content, suggesting that training improves intrinsic skeletal muscle mitochondrial capacity.

Jujuboside A inhibits oxidative stress damage and enhances immunomodulatory capacity of human umbilical cord mesenchymal stem cells through up-regulating IDO expression.

Impaired immunomodulatory capacity and oxidative stress are the key factors limiting the effectiveness of mesenchymal stem cell transplantation therapy. The present study was aimed to investigate the effects of jujuboside A (JuA) on the protective effect and immunomodulatory capacity of human umbilical cord mesenchymal stem cells (hUC-MSCs). Hydrogen peroxide was used to establish an oxidative damage model of hUC-MSCs, while PBMCs isolated from rats were used to evaluate the effect of JuA pre-treatment on the immunomodulatory capacity of hUC-MSCs. Furthermore, Hoechst 33258 staining, lactate dehydrogenase test, measurement of malondialdehyde, Western blot, high-performance liquid chromatography; and flow cytometry were performed. Our results indicated that JuA (25 μmol·L-1) promoted the proliferation of hUC-MSCs, but did not affect the differentiating capability of these cells. JuA pre-treatment inhibited apoptosis, prevented oxidative damage, and up-regulated the protein expression of nuclear factor-erythroid factor 2-related factor 2 and heme oxygenase 1 in hUC-MSCs in which oxidative stress was induced with H2O2. In addition, JuA pre-treatment enhanced the inhibitory effect of hUC-MSCs against abnormally activated PBMCs, which was related to stimulation of the expression and activity of indoleamine 2,3-dioxygenase. In conclusion, our results demonstrate that JuA pre-treatment can enhance the survival and immunomodulatory ability through pathways related to oxidative stress, providing a new option for the improvement of hUC-MSCs in the clinical setting.

Distinct interactors define the p63 transcriptional signature in epithelial development or cancer.

The TP63 is an indispensable transcription factor for development and homeostasis of epithelia and its derived glandular tissue. It is also involved in female germline cell quality control, muscle and thymus development. It is expressed as multiple isoforms transcribed by two independent promoters, in addition to alternative splicing occurring at the mRNA 3′-UTR. Expression of the TP63 gene, specifically the amino-deleted p63 isoform, ΔNp63, is required to regulate numerous biological activities, including lineage specification, self-renewal capacity of epithelial stem cells, proliferation/expansion of basal keratinocytes, differentiation of stratified epithelia. In cancer, ΔNp63 is implicated in squamous cancers pathogenesis of different origin including skin, head and neck and lung and in sustaining self-renewal of cancer stem cells. How this transcription factor can control such a diverse set of biological pathways is central to the understanding of the molecular mechanisms through which p63 acquires oncogenic activity, profoundly changing its down-stream transcriptional signature. Here, we highlight how different proteins interacting with p63 allow it to regulate the transcription of several central genes. The interacting proteins include transcription factors/regulators, epigenetic modifiers, and post-transcriptional modifiers. Moreover, as p63 depends on its interactome, we discuss the hypothesis to target the protein interactors to directly affect p63 oncogenic activities and p63-related diseases.

Aberrant activation of p53/p66Shc-mInsc axis increases asymmetric divisions and attenuates proliferation of aged mammary stem cells.

Aging is accompanied by the progressive decline in tissue regenerative capacity and functions of resident stem cells (SCs). Underlying mechanisms, however, remain unclear. Here we show that, during chronological aging, self-renewing mitoses of mammary SCs (MaSCs) are preferentially asymmetric and that their progeny divides less frequently, leading to decreased number of MaSCs and reduced regenerative potential. Underlying mechanisms are investigated in the p66Shc-/- mouse, which exhibits several features of delayed aging, including reduced involution of the mammary gland (MG). p66Shc is a mitochondrial redox sensor that activates a specific p53 transcriptional program, in which the aging-associated p44 isoform of p53 plays a pivotal role. We report here that aged p66Shc-/- MaSCs show increased symmetric divisions, increased proliferation and increased regenerative potential, to an extent reminiscent of young wild-type (WT) MaSCs. Mechanistically, we demonstrate that p66Shc, together with p53: (i) accumulates in the aged MG, (ii) sustains expression of the cellpolarity determinant mInscuteable and, concomitantly, (iii) down-regulates critical cellcycle genes (e.g.,: Cdk1 and Cyclin A). Accordingly, overexpression of p53/p44 increases asymmetric divisions and decreases proliferation of young WT MaSCs in a p66Shc-dependent manner and overexpression of mInsc restores WT-like levels of asymmetric divisions in aged p66Shc-/- MaSCs. Notably, deletion of p66Shc has negligible effects in young MaSCs and MG development. These results demonstrate that MG aging is due to aberrant activation of p66Shc, which induces p53/p44 signaling, leading to failure of symmetric divisions, decreased proliferation and reduced regenerative potential of MaSCs.

Galunisertib attenuates progression of trauma-induced heterotopic ossification via blockage of Smad2/3 signaling in mice

Heterotopic ossification (HO) is the formation of bony tissues in the extraskeletal system. To date, no effective therapy has been developed for the treatment of HO, although increasing evidences have shown that inhibition of TGF-β signaling has potential as a new therapeutic approach for attenuating HO progression. Results from previous clinical trials have demonstrated that patients with malignant tumors exhibit excellent tolerability to Galunisertib, a TGF-β receptor I kinase inhibitor. However, its therapeutic potential in preventing HO and inhibitory effect on osteogenesis remain unclear. In this study, we demonstrated that intragastrical administration of Galunisertib, at a concentration as low as 10 mg/kg, was not only fairly effective in preventing HO development in a dose-dependent manner, but also generated a non-toxic response in a novel Achilles tendon puncture-induced traumatic HO model in mice. Moreover, Galunisertib treatment in the early phases of HO development, including the inflammatory and chondrogenic period, resulted in better therapeutic effects instead of eliminating already formed bony tissues. Mechanistically, Galunisertib suppressed the osteogenic differentiation capacity of tendon-derived stem cells (TDSCs) by interfering with the Smad2/3 signaling pathway, blocking the phosphorylation of Smad2/3 translocated from cytoplasm into the nucleus to regulate the expression of both osteogenesis-related transcription factors and related proteins. Results from in vivo experiments further validated Galunisertib's effect on HO attenuation, by intercepting the TGF-β/Smad2/3 signaling pathway. In conclusion, our findings demonstrated Galunisertib's potential as a prophylactic drug for the treatment of traumatic HO or other related diseases triggered by over-expressed TGF-β.

Single-cell epigenetic analysis reveals principles of chromatin states in H3.3-K27M gliomas

Cancer cells are highly heterogeneous at the transcriptional level and epigenetic state. Methods to study epigenetic heterogeneity are limited in throughput and information obtained per cell. Here, we adapted cytometry by time-of-flight (CyTOF) to analyze a wide panel of histone modifications in primary tumor-derived lines of diffused intrinsic pontine glioma (DIPG). DIPG is a lethal glioma, driven by a histone H3 lysine 27 mutation (H3-K27M). We identified two epigenetically distinct subpopulations in DIPG, reflecting inherent heterogeneity in expression of the mutant histone. These two subpopulations are robust across tumor lines derived from different patients and show differential proliferation capacity and expression of stem cell and differentiation markers. Moreover, we demonstrate the use of these high-dimensional data to elucidate potential interactions between histone modifications and epigenetic alterations during the cell cycle. Our work establishes new concepts for the analysis of epigenetic heterogeneity in cancer that could be applied to diverse biological systems.

Diabetes impairs osteogenic differentiation of bone marrow mesenchymal stem cells

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Spanish Ministry of Science and Innovation (MICINN) Diabetes impairs osteogenic differentiation of bone marrow mesenchymal stem cells Background Diabetes is a severe metabolic condition that induces micro- and macrovascular disease, including atherosclerotic vascular disease, cutaneous lesions and bone necrosis. Whether it affects stem cell function is a matter of investigation. When the self-renewing capacity of mesenchymal stem cells (MSC) is compromised, their regenerative potential for cell therapy is impaired. Purpose We aimed to investigate the effects of diabetes on bone marrow- mesenchymal stem cells (BM-MSC) transcriptomics to evidence their potential for differentiation. Methods Bone marrow was extracted from femurs of Zucker rats, and BM-MSC were isolated by culturing adherent cells of extracted bone marrow in DMEM low glucose/ 20% FBS/ 1% P/S under hypoxic conditions (1% oxygen). After one week, MSC were characterized by flow cytometry. Gene expression arrays were used to analyse the expression of BM-MSC of Zucker rats with diabetes (ZD) compared to those of lean-normoglycemic controls (ZC) with the same genetic background (n=6). Results were analysed in silico to identify significantly modified signalling pathways. In addition, BM-MSC differentiation into endothelial, adipogenic and osteogenic cells was investigated in vitro. Results 95-99% of cells isolated from BM expressed CD90, a marker of MSC. Expression data analyses revealed a down-regulation of transcription factors related to the osteogenic pathway (Abcb1a, Adipoq, Fut1, Il1b, Kdr, Nes, Rhoa, Runx2, Tbx5, Tert and Tgfb3), and up-regulation of adipogenic- and angiogenic-related genes such as Bmp7, Casp3, Cd44, Csf2, Erbb2, Gdf7, Il10, Mcam, Nt5e, Pparg, Sox2, Vegfa and Vwf, in BM-MSC from animals with diabetes compared to lean controls. Concomitantly, BM-MSC from rats with diabetes showed impaired osteogenic differentiation in vitro compared to lean controls. No significant differences in adipogenesis or endothelial differentiation were observed between BM-MSC of rats with diabetes and lean controls. Conclusions Diabetes down-regulates several factors involved in the osteogenic differentiation pathway resulting in impaired osteogenesis. The imbalance in gene expression and MSC differentiation may partially explain the impaired regenerative capacity in diabetes.

Reactive Oxygen Species and Metabolism in Leukemia: A Dangerous Liaison.

Reactive oxygen species (ROS), previously considered toxic by-products of aerobic metabolism, are increasingly recognized as regulators of cellular signaling. Keeping ROS levels low is essential to safeguard the self-renewal capacity of hematopoietic stem cells (HSC). HSC reside in a hypoxic environment and have been shown to be highly dependent on the glycolytic pathway to meet their energy requirements. However, when the differentiation machinery is activated, there is an essential enhancement of ROS together with a metabolic shift toward oxidative metabolism. Initiating and sustaining leukemia depend on the activity of leukemic stem cells (LSC). LSC also show low ROS levels, but unlike HSC, LSC rely on oxygen to meet their metabolic energetic requirements through mitochondrial respiration. In contrast, leukemic blasts show high ROS levels and great metabolic plasticity, both of which seem to sustain their invasiveness. Oxidative stress and metabolism rewiring are recognized as hallmarks of cancer that are intimately intermingled. Here we present a detailed overview of these two features, sustained at different levels, that support a two-way relationship in leukemia. Modifying ROS levels and targeting metabolism are interesting therapeutic approaches. Therefore, we provide the most recent evidence on the modulation of oxidative stress and metabolism as a suitable anti-leukemic approach.

Biting into a union of oncology and metabolism through leukemic stem cells

In this issue of Cell Metabolism, Liu etal. demonstrate that Prmt7 can regulate the onset and progression of leukemogenesis by inhibiting self-renewal capacity of leukemic stem cells (LSCs) as modeled in a murine version of chronic myeloid leukemia (CML).

3D-printed scaffold with halloysite nanotubes laden as a sequential drug delivery system regulates vascularized bone tissue healing

Bone repair is a complex, multi-stage process, involving angiogenesis and osteogenesis, under the control of sequential stimulation from multiple factors such as FGFs, VEGF, and BMP2. Promoting the bone repair processes at different stages can greatly shorten the period and improve the quality of repair. How to deliver angiogenic and osteogenic cues in sequence still remains a challenge. Therefore, this research proposed a 3D-printed scaffold with a sequential delivery platform loaded with nanotubes and microspheres to realize the coupling regeneration of blood vessels and bones. Deferoxamine was loaded onto halloysite nanotubes by electrostatic interaction to promote the pre-vascularization of the defect area, which can provide a better blood supply for the subsequent regeneration of bone tissue. BMP2 was encapsulated into the microspheres to achieve continuous long-term osteogenic induction. The PLGA/TCP solution mixed with microspheres and halloysite nanotubes was shaped into a scaffold by 3D low-temperature deposition printing to ensure drug inactivation did not occur. The drug delivery system inside the scaffold released pro-angiogenic drugs within the first week of repair and maintained an effective level of bone regeneration-promoting growth factor for an extended period, consistent with the cascade of the natural bone repair process. In vitro results revealed that the scaffold could enhance the proliferation capacity and osteogenic process of bone marrow mesenchymal stem cells (BMSCs), as well as the proliferation and adherent junctions of human umbilical endothelial cells (HUVECs). Furthermore, subcutaneous ectopic experiments demonstrated better angiogenesis and osteoinductive effects in vivo, which is characterized by collagen deposition, the number of capillaries and calcium nodules. Current study highlights the great potential of scaffold with a sequential delivery platform for clinical application.

Differentiation Capacity of Human Urine-Derived Stem Cells to Retain Telomerase Activity.

Telomerase activity is essential for the self-renewal and potential of embryonic, induced pluripotent, and cancer stem cells, as well as a few somatic stem cells, such as human urine-derived stem cells (USCs). However, it remains unclear how telomerase activity affects the regeneration potential of somatic stem cells. The objective of this study was to determine the regenerative significance of telomerase activity, particularly to retain cell surface marker expression, multipotent differentiation capability, chromosomal stability, and in vivo tumorigenic transformation, in each clonal population of human primary USCs. In total, 117 USC specimens from 10 healthy male adults (25–57 years of age) were obtained. Polymerase chain reaction amplification of a telomeric repeat was used to detect USCs with positive telomerase activity (USCsTA+). A total of 80 USCsTA+ (70.2%) were identified from 117 USC clones, but they were not detected in the paired normal bladder smooth muscle cell and bone marrow stromal cell specimens. In the 20–40 years age group, approximately 75% of USC clones displayed positive telomerase activity, whereas in the 50 years age group, 59.2% of the USC clones expressed positive telomerase activity. USCsTA+ extended to passage 16, underwent 62.0 ± 4.8 population doublings, produced more cells, and were superior for osteogenic, myogenic, and uroepithelial differentiation compared to USCsTA−. Importantly, USCs displayed normal chromosome and no oncological transformation after being implanted in vivo. Overall, as a safe cell source, telomerase-positive USCs have a robust regenerative potential in cell proliferation and multipotent differentiation capacity.

Effects of Systemic or Local Administration of Mesenchymal Stem Cells from Patients with Osteoporosis or Osteoarthritis on Femoral Fracture Healing in a Mouse Model.

The purpose of this study was to analyze the regenerative capacity of mesenchymal stem cells (MSCs) in the treatment of fractures. MSCs extracted from patients with osteoporotic hip fractures or hip osteoarthritis undergoing hip replacement surgeries were cultured and injected into mice with femoral fracture. Two experimental models were established, one for the systemic administration of MSCs (n = 29) and another one for local administration (n = 30). Fracture consolidation was assessed by micro-CT and histology. The degree of radiological consolidation and corticalization was better with MSCs from osteoporosis than from osteoarthritis, being significant after systemic administration (p = 0.0302 consolidation; p = 0.0243 corticalization). The histological degree of consolidation was also better with MSCs from osteoporosis than from osteoarthritis. Differences in histological scores after systemic infusion were as follows: Allen, p = 0.0278; Huo, p = 0.3471; and Bone Bridge, p = 0.0935. After local administration at the fracture site, differences in histological scores were as follows: Allen, p = 0.0764; Huo, p = 0.0256; and Bone Bridge, p = 0.0012. As osteoporosis and control groups were similar, those differences depended on an inhibitory influence by MSCs from patients with osteoarthritis. In conclusion, we found an unexpected impairment of consolidation induced by MSCs from patients with osteoarthritis. However, MSCs from patients with osteoporosis compared favorably with cells from patients with osteoarthritis. In other words, based on this study and previous studies, MSCs from patients with osteoporosis do not appear to have worse bone-regenerating capabilities than MSCs from non-osteoporotic individuals of similar age.