Stem Cells International最新文献

Background: The periosteum plays an indispensable role in bone repair, and promoting osteogenic differentiation of periosteum-derived stem cells (PDSCs) is one of the most effective strategies for enhancing spontaneous bone regeneration in maxillofacial bone defects. Methods: We established a rat model of mandibular defects with preserved periosteum to explore its bone regeneration capacity and the potential mechanisms of PDSC activation and osteogenic differentiation. Results: Significant bone regeneration was observed in rats with preserved periosteum after mandibular defects. To explore the underlying mechanisms, PDSCs were isolated from the periosteum of rat mandibles, and the stem cell markers CD90 and CD44 was highly expressed in these PDSCs. Further, RNA-seq, RT-qPCR, and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional analyses revealed significantly reduced expression of the Dot1l gene, and the Notch pathway was significantly enriched in the PDSCs of the model group. Osteogenic assays demonstrated that the overexpression of Dot1l significantly inhibited the alkaline phosphatase (ALP) activity, calcium deposition, and the expression of osteogenic-related genes (such as RUNX2, OSX, ALP, and OCN) in PDSCs. Additionally, Dot1l significantly affects the Notch signaling pathway in the Gene Ontology (GO) pathways, and significantly downregulates the expression of Chac1 within it. Further, Dot1l inhibited ALP activity, calcium deposition, and the expression of osteogenic-related genes in PDSCs by downregulating Chac1 expression. Conclusions: Our study suggests that mandibular defects can induce the activation of PDSCs and inhibit the expression of Dot1l, potentially affecting the Notch signaling pathway. Targeting the Dot1l/Chac1 pathway to regulate the osteogenic differentiation of PDSCs lays a solid foundation for periosteum-based maxillofacial bone regeneration.

Mesenchymal stem cells (MSCs) exhibit great promise for treatment applications because of their immunosuppressive properties. The aryl hydrocarbon receptor (AHR), which is a transcription factor that is activated via ligand, has a pivotal role in regulating the immune system and is involved in a range of immune-related disorders. However, hyperglycemia, the defining biochemical hallmark of diabetes, creates a chronically pro-inflammatory microenvironment that impairs the immunoregulatory effects of MSCs. In this study, we explored the potential of kynurenic acid (KYNA) and quercetin, two naturally derived compounds, to modulate the immune response of MSCs through the regulation of AHR signaling under hyperglycemic conditions. We assessed the immunophenotyping and differentiation capacity of cultured human umbilical cord mesenchymal stem cells (hUC-MSCs) in a high-glucose medium and quantified the mRNA expression rate of AHR, CYP1A1, CYP1B1, and IL-6 using real time PCR. Our study is the first to reveal that KYNA and quercetin enhance mRNA expression levels of AHR and CYP1B1, while reducing IL-6 expression in hUC-MSCs, suggesting their potential as immunomodulators. These findings highlight the compounds' promise as drug candidates for immune-mediated diseases through stem cell therapy, particularly due to their modulation of AHR.

Mesenchymal stromal cells (MSCs) are recognized for their differentiation and immune regulation capabilities, which enhance their potential for treating various diseases. MSCs can be sourced from diverse tissues, with peripheral blood (PB) serving as a viable alternative to bone marrow. We now present an alternative strategy that eliminates the need for preadministering growth factors, utilizing density gradient methods, and culturing target cells in medium supplemented with autologous serum. PB was collected through venipuncture and then coincubated with glycerin. After incubation, a thin layer of cells above the red blood cells (RBCs) was isolated, showing an increased population of CD34^-CD45^- cells compared to PB mononuclear cell (PBMC) isolation using Ficoll gradient. After culture, adherent spindle-shaped cells were identified and collected to assess MSC surface markers, demonstrating their differentiation potential into adipocytes, osteocytes, and chondrocytes, thus, fulfilling the criteria for MSCs. The population doubling time (PDT) of isolated PB-MSCs was approximately 30-40 h in early passages. These PB-MSCs also exhibited immunomodulatory functions and are capable of suppressing T cell activation. We believe this protocol supports PB as a convenient alternative source for MSC isolation and offers new strategies for acquiring and maintaining PB-MSCs.

Background: In recent years, liver regeneration therapy using mesenchymal stem cells (MSC) has been investigated as an alternative therapy for end-stage liver diseases. Among these MSCs, multilineage-differentiating stress enduring (Muse) cells are reported to be effective in mouse models. The present study investigated the safety and effectiveness of Muse cell transplantation in large animal models of hepatic fibrosis. Methods: Muse cells and MSC were prepared from bone marrow cells of male mini pigs (Göttingen strain). Recipients mini pigs (female Göttingen strain) were repeatedly administered with carbon tetrachloride (CCl₄) intraperitoneally for 12 weeks to induce liver fibrosis. Thereafter, either Muse cells or MSCs were transplanted intravenously. After the cell transplantation, laboratory tests, vital signs, and liver histology were evaluated (Muse cell group (n = 6), MSC group (n = 6), and vehicle group (n = 7)). Results: Liver fibrogenesis was successfully induced after 12 weeks of CCl₄ administration. Engraftment of transplanted cells and differentiation into hepatocytes were confirmed in recipients' liver. In Muse cell group, significant increase of serum albumin (Alb) level was observed at 4 weeks compared to those of control groups (p  < 0.05). Hepatic proliferating cell nuclear antigen (PCNA) positive cells were significantly increased in the Muse cell group (p  < 0.05). Hepatic fibrogenesis at 12 weeks after transplantation were significantly improved in Muse cell group (p  < 0.05). Alpha-smooth muscle actin (α-SMA) immunostaining revealed significant decrease in liver from Muse cell transplanted recipients. No serious adverse effects were observed. Conclusions: Muse cell transplantation was safe and effective in large animal models of hepatic fibrosis. The positive effects were observed in namely 4 weeks after transplantation. Since biochemical as well as histological improvements were demonstrated, future studies including establishing ideal administration protocol seem to be feasible as a preclinical study.

Intervertebral disc degeneration (IDD) is a major contributor to low back pain, a prevalent and debilitating condition. Nucleus pulposus (NP) cells are essential for maintaining disc homeostasis, and their dysfunction plays a crucial role in IDD development. This study aimed to explore the potential role of miR-1275, delivered via mesenchymal stem cell-derived extracellular vesicles (MSCs-EVs), in IDD pathogenesis and to elucidate the underlying molecular mechanisms through in vitro investigations. Decreased miR-1275 expression and elevated endoplasmic reticulum (ER) stress were observed in degenerated human NP tissues compared to normal controls. An in vitro IDD model was established by treating NP cells (NPCs) with advanced glycation end products (AGEs). Subsequent experiments demonstrated that EVs from miR-1275-overexpressing MSCs reduced AGE-induced ER stress, extracellular matrix (ECM) degradation, and apoptosis in NPCs by enhancing ER-phagy. Bioinformatic analyses identified AXIN2 as a direct target of miR-1275. Remarkably, AXIN2 overexpression significantly attenuated the effects of miR-1275 on NPC proliferation, apoptosis, ER stress, and ER-phagy under AGE-induced conditions. Mechanistic studies validated AXIN2 as a target of miR-1275, with miR-1275 binding to the 3' untranslated region of AXIN2 and regulating its expression. Collectively, our in vitro findings reveal that MSCs-EVs carrying miR-1275 can modulate ER stress and enhance ER-phagy in NPCs through the targeted downregulation of AXIN2, suggesting a potential molecular mechanism in IDD pathogenesis.

[This corrects the article DOI: 10.1155/2021/8307797.].

Background: CXCR4 enhances the homing of mesenchymal stem cells (MSCs), thereby potentially improving outcomes in myocardial infarction (MI). However, the molecular mechanisms underlying MSC homing remain poorly understood. Methods: The identity of MSCs was confirmed through flow cytometry, utilizing their cluster of differentiation (CD) marker profile. Migration and invasion were assessed using wound healing and transwell assays. In a rat MI model, myocardial function, hemodynamic parameters, and the degree of myocardial fiber damage were evaluated post-MSC treatment, along with the observation of MSC homing. Luciferase assays identified binding sites between SOX10 and the CXCR4 promoter, and the effects of SOX10 on MSC migration, invasion, and homing were explored both in vitro and in vivo. Results: Overexpression of CXCR4 significantly enhanced MSC migration, invasion, and homing. MSCs overexpressing CXCR4 improved cardiac function and reduced infarct size in the rat MI model. A direct interaction between SOX10 and CXCR4 was confirmed, with SOX10 acting as a transcription factor to upregulate CXCR4 expression, thereby enhancing MSC homing and ameliorating MI in rats. Knockdown of SOX10 reversed the beneficial effects of CXCR4-overexpressing MSCs on MI therapy, as well as the functional impact of CXCR4 on MSCs. Conclusion: In conclusion, SOX10 facilitates MSC homing by upregulating CXCR4 expression, offering a potential therapeutic approach for MI treatment.

Recent evidence indicates the potential of gamma-irradiated (γi) Staphylococcus aureus to be used as an osteo-immunomodulator for bone regeneration. This study aims at characterizing the inflammatory milieu caused by the stimulation of γi S. aureus in immune cells and investigates its effects on MSC osteogenic differentiation. Furthermore, we aimed to recreate the immune-modulatory response exhibited by γi S. aureus by using a mixture of various synthetic pathogen recognition receptor (PRR) ligands consisting of TLR2, TLR8, TLR9, and NOD2 agonists. Human peripheral blood mononuclear cells (hPBMCs), isolated from healthy human donors, were exposed to γi S. aureus or seven different ligand mixtures. After 24 h, the conditioned medium (CM) from the hPBMCs was collected and its effects on hMSC osteogenic differentiation were investigated by assessing alkaline phosphatase (ALP) activity and matrix mineralization. The hPBMCs and their CM were also analyzed by bulk RNA sequencing and for cytokine secretion. CM from the γi S. aureus and the mixture consisting of Pam3CSK4, C-class CpG oligodeoxynucleotide (CpG ODN C), and murabutide targeting TLR2, TLR9, and NOD2 showed a fivefold increase in ALP and matrix mineralization in a donor-dependent manner. These effects were due to the upregulation of inflammatory signaling pathways, which led to an increase in cytokines and chemokines TNF, interleukin (IL)-6, IFN-γ, IL-1α, CXCL10, CCL18, CCL17, CXCL1, and CCL5. Upregulation of genes like BMP2R, BMP6R, BGLAP, and others contributed to the upregulation of osteogenic pathways in the hPBMCs stimulated with γi S. aureus and the aforementioned mix. Thus, formulations with mixtures of PRR ligands may serve as immune-modulatory osteogenesis-enhancing agents.

Idiopathic pulmonary fibrosis (IPF) is a long-term, diffuse pulmonary parenchyma lesion that primarily affects middle-aged and older adults. It is characterized by pulmonary interstitial fibrosis of unknown cause. The death rate upon diagnosis is higher than that of many other cancer types. Mesenchymal stem cell (MSC) treatment of organ fibrosis is a hot topic in preclinical and clinical research because it effectively treats IPF. In recent years, decorin (DCN) has been regarded as a critical mediator for its anti-inflammatory and antifibrotic effects. The purpose of this study was to generate human umbilical cord MSCs (HUC-MSCs) that overexpress DCN and to investigate the safety, mechanism, and effectiveness of using these cells to cure pulmonary fibrosis caused by bleomycin (BLM). First, lentiviral (LV) particles carrying the therapeutic DCN gene (LV-DCN) and control LV particles were created and transfected using the plasmid vector GV208 to create a viral solution for infecting HUC-MSCs. These solutions were used to create a DCN overexpression cell line and an MSC-Con. cell line infected with the control lentivirus. Intratracheal injection of BLM was used to establish a rat model of pulmonary fibrosis. On the second day following modeling, different treatments were administered, and the body weight and survival status of the rats were noted. The relevant tests were performed on days 15 and 29 following modeling. The results demonstrated that the overexpression of DCN did not affect the properties of HUC-MSCs and that these cells were effective in treating IPF. MSC-Con. and MSC-DCN reduced systemic inflammation by reducing serum interleukin (IL) 1β. Both cell types successfully treated pulmonary fibrosis in rats, as demonstrated by hematoxylin and eosin (HE) and Masson staining. MSC-DCN showed better efficacy due to lower mortality, higher weight gain, less alveolar inflammation, and less fibrosis. The safety of venous transplantation with MSCs was established by HE staining of the heart, liver, spleen, and kidney, as well as serum lactate dehydrogenase (LDH), creatinine (CRE), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels. Immunohistochemical (IHC) staining of CD68 and CD206 in lung tissue and in vitro experiments on THP-1-induced M2 macrophage polarization and transforming growth factor-beta 1 (TGF-β1)-induced MRC-5 fibrosis indicated that MSC-DCN may mitigate lung inflammation by altering macrophage recruitment and polarization and inhibiting TGF-β1 expression to reduce fibrous hyperplasia and collagen deposition, thereby improving the treatment of BLM-induced IPF.