Muse Cells and Aortic Aneurysm

Multilineage-differentiating stress-enduring cells: a powerful tool for tissue damage repair

Multilineage-differentiating stress-enduring (Muse) cells are a type of pluripotent cell with unique characteristics such as non-tumorigenic and pluripotent differentiation ability. After homing, Muse cells spontaneously differentiate into tissue component cells and supplement damaged/lost cells to participate in tissue repair. Importantly, Muse cells can survive in injured tissue for an extended period, stabilizing and promoting tissue repair. In addition, it has been confirmed that injection of exogenous Muse cells exerts anti-inflammatory, anti-apoptosis, anti-fibrosis, immunomodulatory, and paracrine protective effects in vivo. The discovery of Muse cells is an important breakthrough in the field of regenerative medicine. The article provides a comprehensive review of the characteristics, sources, and potential mechanisms of Muse cells for tissue repair and regeneration. This review serves as a foundation for the further utilization of Muse cells as a key clinical tool in regenerative medicine.

Identification of co-diagnostic effect genes for aortic dissection and metabolic syndrome by multiple machine learning algorithms

Aortic dissection (AD) is a life-threatening condition in which the inner layer of the aorta tears. It has been reported that metabolic syndrome (MS) has a close linkage with aortic dissection. However, the inter-relational mechanisms between them were still unclear. This article explored the hub gene signatures and potential molecular mechanisms in AD and MS. We obtained five bulk RNA-seq datasets of AD, one single cell RNA-seq (scRNA-seq) dataset of ascending thoracic aortic aneurysm (ATAA), and one bulk RNA-seq dataset of MS from the gene expression omnibus (GEO) database. Identification of differentially expressed genes (DEGs) and key modules via weighted gene co-expression network analysis (WGCNA), functional enrichment analysis, and machine learning algorithms (Random Forest and LASSO regression) were used to identify hub genes for diagnosing AD with MS. XGBoost further improved the diagnostic performance of the model. The receiver operating characteristic (ROC) and precision-recall (PR) curves were developed to assess the diagnostic value. Then, immune cell infiltration and metabolism-associated pathways analyses were created to investigate immune cell and metabolism-associated pathway dysregulation in AD and MS. Finally, the scRNA-seq dataset was performed to confirm the expression levels of identified hub genes. 406 common DEGs were identified between the merged AD and MS datasets. Functional enrichment analysis revealed these DEGs were enriched for applicable terms of metabolism, cellular processes, organismal systems, and human diseases. Besides, the positively related key modules of AD and MS were mainly enriched in transcription factor binding and inflammatory response. In contrast, the negatively related modules were significantly associated with adaptive immune response and regulation of nuclease activity. Through machine learning, nine genes with common diagnostic effects were found in AD and MS, including MAD2L2, IMP4, PRPF4, CHSY1, SLC20A1, SLC9A1, TIPRL, DPYD, and MAPKAPK2. In the training set, the AUC of the hub gene on RP and RR curves was 1. In the AD verification set, the AUC of the Hub gene on RP and RR curves were 0.946 and 0.955, respectively. In the MS set, the AUC of the Hub gene on RP and RR curves were 0.978 and 0.98, respectively. scRNA-seq analysis revealed that the SLC20A1 was found to be relevant in fatty acid metabolic pathways and expressed in endothelial cells. Our study revealed the common pathogenesis of AD and MS. These common pathways and hub genes might provide new ideas for further mechanism research.

Multilineage Differentiating Stress Enduring (Muse) Cells: A New Era of Stem Cell-Based Therapy

Stem cell transplantation has recently demonstrated a significant therapeutic efficacy in various diseases. Multilineage-differentiating stress-enduring (Muse) cells are stress-tolerant endogenous pluripotent stem cells that were first reported in 2010. Muse cells can be found in the peripheral blood, bone marrow and connective tissue of nearly all body organs. Under basal conditions, they constantly move from the bone marrow to peripheral blood to supply various body organs. However, this rate greatly changes even within the same individual based on physical status and the presence of injury or illness. Muse cells can differentiate into all three-germ-layers, producing tissue-compatible cells with few errors, minimal immune rejection and without forming teratomas. They can also endure hostile environments, supporting their survival in damaged/injured tissues. Additionally, Muse cells express receptors for sphingosine-1-phosphate (S1P), which is a protein produced by damaged/injured tissues. Through the S1P-S1PR2 axis, circulating Muse cells can preferentially migrate to damaged sites following transplantation. In addition, Muse cells possess a unique immune privilege system, facilitating their use without the need for long-term immunosuppressant treatment or human leucocyte antigen matching. Moreover, they exhibit anti-inflammatory, anti-apoptotic and tissue-protective effects. These characteristics circumvent all challenges experienced with mesenchymal stem cells and induced pluripotent stem cells and encourage the wide application of Muse cells in clinical practice. Indeed, Muse cells have the potential to break through the limitations of current cell-based therapies, and many clinical trials have been conducted, applying intravenously administered Muse cells in stroke, myocardial infarction, neurological disorders and acute respiratory distress syndrome (ARDS) related to novel coronavirus (SARS-CoV-2) infection. Herein, we aim to highlight the unique biological properties of Muse cells and to elucidate the advantageous difference between Muse cells and other types of stem cells. Finally, we shed light on their current therapeutic applications and the major obstacles to their clinical implementation from laboratory to clinic.

Multilineage-Differentiating Stress-Enduring Cells (Muse Cells): The Future of Human and Veterinary Regenerative Medicine

In recent years, several studies have been conducted on Muse cells mainly due to their pluripotency, high tolerance to stress, self-renewal capacity, ability to repair DNA damage and not being tumoral. Additionally, since these stem cells can be isolated from different tissues in the adult organism, obtaining them is not considered an ethical problem, providing an advantage over embryonic stem cells. Regarding their therapeutic potential, few studies have reported clinical applications in the treatment of different diseases, such as aortic aneurysm and chondral injuries in the mouse or acute myocardial infarction in the swine, rabbit, sheep and in humans. This review aims to describe the characterization of Muse cells, show their biological characteristics, explain the differences between Muse cells and mesenchymal stem cells, and present their contribution to the treatment of some diseases.

Aortic Aneurysms and Dissections Series: Part II: Dynamic Signaling Responses in Aortic Aneurysms and Dissections

Aortic structure and function are controlled by the coordinated actions of different aortic cells and the extracellular matrix. Several pathways have been identified that control the aortic wall in a cell-type-specific manner and play diverse roles in various phases of aortic injury, repair, and remodeling. This complexity of signaling in the aortic wall poses challenges to the development of therapeutic strategies for treating aortic aneurysms and dissections. Here, in part II of this Recent Highlights series on aortic aneurysms and dissections, we will summarize recent studies published in Arteriosclerosis, Thrombosis, and Vascular Biology that have contributed to our knowledge of the signaling pathway-related mechanisms of aortic aneurysms and dissections.

Study of the protective effect on damaged intestinal epithelial cells of rat multilineage-differentiating stress-enduring (Muse) cells

In this study, we determined whether multilineage‐differentiating stress‐enduring (Muse) cells exist in rat bone marrow and elucidated their effects on protection against the injury of intestinal epithelial cells associated with inflammation. Rat Muse cells were separated from bone marrow mesenchymal stem cells (BMMSCs) by trypsin‐incubation stress. The group of cells maintained the characteristics of BMMSCs; however, there were high positive expression levels of stage‐specific embryonic antigen‐3 (SSEA‐3; 75.6 ± 2.8%) and stage‐specific embryonic antigen‐1 (SSEA‐1; 74.8 ± 3.1%), as well as specific antigens including Nanog, POU class 5 homeobox 1 (OCT 3/4), and SRY‐box 2 (SOX 2). After inducing differentiation, α‐fetoprotein (endodermal), α‐smooth muscle actin and neurofilament medium polypeptide (ectodermal) were positive in Muse cells. Injuries of intestinal epithelial crypt cell‐6 (IEC‐6) and colorectal adenocarcinoma 2 (Caco‐2) cells as models were induced by tumor necrosis factor‐α stimulation in vitro. Muse cells exhibited significant protective effects on the proliferation and intestinal barrier structure, the underlying mechanisms of which were related to reduced levels of interleukin‐6 (IL‐6) and interferon‐γ (IFN‐γ), and the restoration of transforming growth factor‐β (TGF‐β) and IL‐10 in the inflammation microenvironment. In summary, there were minimal levels of pluripotent stem cells in rat bone marrow, which exhibit similar properties to human Muse cells. Rat Muse cells could provide protection against damage to intestinal epithelial cells depending on their anti‐inflammatory and immune regulatory functionality. Their functional impact was more obvious than that of BMMSCs.

Rescue from Stx2-Producing E. coli-Associated Encephalopathy by Intravenous Injection of Muse Cells in NOD-SCID Mice

Shiga toxin-producing Escherichia coli (STEC) causes hemorrhagic colitis, hemolytic uremic syndrome, and acute encephalopathies that may lead to sudden death or severe neurologic sequelae. Current treatments, including immunoglobulin G (IgG) immunoadsorption, plasma exchange, steroid pulse therapy, and the monoclonal antibody eculizumab, have limited effects against the severe neurologic sequelae. Multilineage-differentiating stress-enduring (Muse) cells are endogenous reparative non-tumorigenic stem cells that naturally reside in the body and are currently under clinical trials for regenerative medicine. When administered intravenously, Musecells accumulate to the damaged tissue, where they exert anti-inflammatory, anti-apoptotic, anti-fibrotic, and immunomodulatory effects, and replace damaged cells by differentiating into tissue-constituent cells. Here, severely immunocompromised non-obese diabetic/severe combined immunodeficiency (NOD-SCID) mice orally inoculated with 9 × 10⁹ colony-forming units of STEC O111 and treated 48 h later with intravenous injection of 5 × 10⁴ Muse cells exhibited 100% survival and no severe after-effects of infection. Suppression of granulocyte-colony-stimulating factor (G-CSF) by RNAi abolished the beneficial effects of Muse cells, leading to a 40% death and significant body weight loss, suggesting the involvement of G-CSF in the beneficial effects of Muse cells in STEC-infected mice. Thus, intravenous administration of Muse cells could be a candidate therapeutic approach for preventing fatal encephalopathy after STEC infection.