Multilineage-differentiating Stress-enduring Cells Research Articles

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.

Systemic administration of clinical-grade multilineage-differentiating stress-enduring cells ameliorates hypoxic–ischemic brain injury in neonatal rats

Multilineage-differentiating stress-enduring (Muse) cells are endogenous reparative pluripotent stem cells present in the bone marrow, peripheral blood, and organ connective tissues. We assessed the homing and therapeutic effects of systemically administered nafimestrocel, a clinical-grade human Muse cell-based product, without immunosuppressants in a neonatal hypoxic–ischemic (HI) rat model. HI injury was induced on postnatal day 7 (P7) and was confirmed by T2-weighted magnetic resonance imaging on P10. HI rats received a single dose nafimestrocel (1 × 106 cells/body) or Hank’s balanced salt solution (vehicle group) intravenously at either three days (on P10; M3 group) or seven days (on P14; M7 group) after HI insult. Radioisotope experiment demonstrated the homing of chromium-51-labeled nafimestrocel to the both cerebral hemispheres. The cylinder test (M3 and M7 groups) and open-field test (M7 group) showed significant amelioration of paralysis and hyperactivity at five weeks of age compared with those in the vehicle group. Nafimestrocel did not cause adverse events such as death or pathological changes in the lung at ten weeks in the both groups. Nafimestrocel attenuated the production of tumor necrosis factor-α and inducible nitric oxide synthase from activated cultured microglia in vitro. These results demonstrate the potential therapeutic benefits and safety of nafimestrocel.

Multilineage-Differentiating Stress-Enduring Cells (Muse Cells): An Easily Accessible, Pluripotent Stem Cell Niche with Unique and Powerful Properties for Multiple Regenerative Medicine Applications.

Cell-based therapy in regenerative medicine is a powerful tool that can be used both to restore various cells lost in a wide range of human disorders and in renewal processes. Stem cells show promise for universal use in clinical medicine, potentially enabling the regeneration of numerous organs and tissues in the human body. This is possible due to their self-renewal, mature cell differentiation, and factors release. To date, pluripotent stem cells seem to be the most promising. Recently, a novel stem cell niche, called multilineage-differentiating stress-enduring (Muse) cells, is emerging. These cells are of particular interest because they are pluripotent and are found in adult human mesenchymal tissues. Thanks to this, they can produce cells representative of all three germ layers. Furthermore, they can be easily harvested from fat and isolated from the mesenchymal stem cells. This makes them very promising, allowing autologous treatments and avoiding the problems of rejection typical of transplants. Muse cells have recently been employed, with encouraging results, in numerous preclinical studies performed to test their efficacy in the treatment of various pathologies. This review aimed to (1) highlight the specific potential of Muse cells and provide a better understanding of this niche and (2) originate the first organized review of already tested applications of Muse cells in regenerative medicine. The obtained results could be useful to extend the possible therapeutic applications of disease healing.

Comparison of the Anti-Inflammatory Effects of Mouse Adipose- and Bone-Marrow-Derived Multilineage-Differentiating Stress-Enduring Cells in Acute-Phase Spinal Cord Injury.

Abstract Spinal cord injury (SCI) is a serious neurological disorder, with the consequent disabilities conferred by this disorder typically persisting for life. Multilineage-differentiating stress-enduring (Muse) cells are endogenous stem cells that can be collected from various tissues as well as from mesenchymal stem cells (MSCs); additionally, these Muse cells are currently being used in clinical trials. The anti-inflammatory effect of stem cell transplantation prevents secondary injuries of SCI; however, its effect on Muse cells remains unclear. In this study, we aimed to compare the anti-inflammatory effects of adipose (AD)- and bone marrow (BM)-Muse cells that were isolated from mice (6-week-old C57BL/6J) following intralesional administration during the acute phase of SCI. Flow cytometry was used to isolate Muse cells from AD and BM MSCs. The percentage of Muse cells was 3.9 and 2.7% for AD and BM MSCs, respectively. To examine cell viability, Muse cells were incubated under H2O2-induced oxidative stress conditions. Overall, AD-Muse cells exhibited higher viability than BM-Muse cells (p = 0.032). In enzyme-linked immunosorbent assay analysis, AD-Muse cells displayed greater secretion of brain-derived neurotrophic factor (BDNF; p = 0.008), vascular endothelial growth factor (p = 0.032), and hepatocyte growth factor (p = 0.016). DNA microarray analysis revealed higher expression of Bdnf, neurotrophin-3 (Ntf3), nerve growth factor (Ngf), pleiotrophin (Ptn), and midkine (Mdk) in AD-Muse cells than in BM-Muse cells. To assess their anti-inflammatory effects in vitro, Muse cells and macrophages were co-cultured, and the levels of cytokines (tumor necrosis factor [TNF] α and interleukin [IL] 10) were measured in the medium. Consequently, we found that TNFα levels were lower in AD-Muse cells than in BM-Muse cells (p = 0.009), and IL10 levels were higher in AD-Muse cells than in BM-Muse cells (p = 0.008). Further, we induced moderate injuries via contusion of the spinal cord at the T10 level; Muse cells were transplanted intralesionally 7 days post-SCI. The number of surviving cells, alongside the number of CD86+ (M1 inflammatory effect), and CD206+ (M2 anti-inflammatory effect) macrophages in the spinal cord were measured 7 days post-transplantation. The number of surviving AD-Muse cells was higher than the number of surviving BM-Muse cells (ratio of AD-Muse/BM-Muse = 2.5, p > 0.05). The M1/M2 ratio in the AD-Muse cell-group (0.37) was lower than that in the control (phosphate-buffered saline) group (3.60, p = 0.008). The lesion area in the AD-Muse cell group was smaller than that in the BM-non-Muse (p = 0.049) and control groups (p = 0.012). As AD-Muse cells conferred a higher cell survival and neurotrophic factor secretion ability in vitro, AD-Muse cells demonstrated reduced inflammation after SCI. Overall, intralesional AD-Muse cell therapy is a potential therapeutic candidate that is expected to exhibit anti-inflammatory effects following acute SCI.

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.

Highly Pluripotent Adipose-Derived Stem Cell–Enriched Nanofat: A Novel Translational System in Stem Cell Therapy

Fat graft is widely used in plastic and reconstructive surgery. The size of the injectable product, the unpredictable fat resorption rates, and subsequent adverse effects make it tricky to inject untreated fat into the dermal layer. Mechanical emulsification of fat tissue, which Tonnard introduced, solves these problems, and the product obtained was called nanofat. Nanofat is widely used in clinical and aesthetic settings to treat facial compartments, hypertrophic and atrophic scars, wrinkle attenuation, skin rejuvenation, and alopecia. Several studies demonstrate that the tissue regeneration effects of nanofat are attributable to its rich content of adipose-derived stem cells. This study aimed to characterize Hy-Tissue Nanofat product by investigating morphology, cellular yield, adipose-derived stem cell (ASC) proliferation rate and clonogenic capability, immunophenotyping, and differential potential. The percentage of SEEA3 and CD105 expression was also analyzed to establish the presence of multilineage-differentiating stress-enduring (MUSE) cell. Our results showed that the Hy-Tissue Nanofat kit could isolate 3.74 × 104 ± 1.31 × 104 proliferative nucleated cells for milliliter of the treated fat. Nanofat-derived ASC can grow in colonies and show high differentiation capacity into adipocytes, osteocytes, and chondrocytes. Moreover, immunophenotyping analysis revealed the expression of MUSE cell antigen, making this nanofat enriched of pluripotent stem cell, increasing its potential in regenerative medicine. The unique characteristics of MUSE cells give a simple, feasible strategy for treating a variety of diseases.

Single-cell RNA sequencing reveals different signatures of mesenchymal stromal cell pluripotent-like and multipotent populations

Somatic stem cells are advantageous research targets for understanding the properties required to maintain stemness. Human bone marrow-mesenchymal stromal cells (BM-MSCs) were separated into pluripotent-like SSEA-3(+) Muse cells (Muse-MSCs) and multipotent SSEA-3(-) MSCs (MSCs) and were subjected to single-cell RNA sequencing analysis. Compared with MSCs, Muse-MSCs exhibited higher expression levels of the p53 repressor MDM2; signal acceptance-related genes EGF, VEGF, PDGF, WNT, TGFB, INHB, and CSF; ribosomal protein; and glycolysis and oxidative phosphorylation. Conversely, MSCs had higher expression levels of FGF and ANGPT; Rho family and caveola-related genes; amino acid and cofactor metabolism; MHC class I/II, and lysosomal enzyme genes than Muse-MSCs. Unsupervised clustering further divided Muse-MSCs into two clusters stratified by the expression of cell cycle-related genes, and MSCs into three clusters stratified by the expression of cell cycle-, cytoskeleton-, and extracellular matrix-related genes. This study evaluating the differentiation ability of BM-MSC subpopulations provides intriguing insights for understanding stemness.

Role of glycosphingolipid SSEA-3 and FGF2 in the stemness and lineage commitment of multilineage differentiating stress enduring (MUSE) cells.

Multilineage differentiating Stress Enduring (MUSE) cells are endogenous, stress-resistant stem cells, expressing pluripotency master genes and able to differentiate in cells of the three embryonic sheets. Stage-Specific Embryonic Antigen 3 (SSEA-3), a glycosphingolipid (GSL), is the marker for identifying MUSE cells and is used to isolate this population from mesenchymal stromal cells. GSLs modulate signal transduction by interacting with plasma membrane components. The growth factor FGF2, important for MUSE cells biology, may interact with GSLs. Specific cell surface markers represent an invaluable tool for stem cell isolation. Nonetheless their role, if any, in stem cell biology is poorly investigated. Functions of stem cells, however, depend on niche external cues, which reach cells through surface markers. We addressed the role of SSEA-3 in MUSE cell behaviour, trying to define whether SSEA-3 is just a marker or if it plays a functional role in this cell population by determining if it has any relationship with FGF2 activity. We evidenced how the SSEA-3 and FGF2 cooperation affected the self-renewal and clonogenic capacity of MUSE cells. The block of SSEA-3 significantly reduced the multilineage potential of MUSE cells with production of nullipotent clones. We contributed to dissecting the mechanisms underlying MUSE cell properties for establishing successful stem-cell-based therapies and the promotion of MUSE cells as a tool for the in vitro disease model.

Mobilization of multilineage-differentiating stress-enduring cells into the peripheral blood in liver surgery.

This study investigated whether liver damage severity relates to the mobilization of multilineage-differentiating stress-enduring (Muse) cells, which are endogenous reparative pluripotent stem cells, into the peripheral blood (PB) and whether the degree of mobilization relates to the recovery of liver volume following human liver surgery. Forty-seven patients who underwent liver surgery were included in the present study. PB-Muse cells were counted before surgery, on postoperative days (PODs) 3 and on POD 7. Liver volume was measured using computed tomography before and after surgery. The PB-Muse cell count increased after surgery. The number of PB-Muse cells before surgery was higher, but without statistical significance in the group with neoplasms than in the healthy group that included liver donors (p = 0.065). Forty-seven patients who underwent liver surgery were divided into major hepatic resection (MHR; hepatectomy of three or more segments according to the Couinaud classification, n = 22) and minor hepatic resection (mhr; hepatectomy of two segments or less according to the Couinaud classification, n = 25) groups. PB-Muse cells increased at high rates among MHR patients (p = 0.033). Except for complication cases, PB-Muse cells increased at higher rates in the group with advanced liver volume recovery (p = 0.043). The predictive impact of the rate of increase in PB-Muse cells on the recovery of liver volume was demonstrated by multivariate analysis (OR 11.0, p = 0.014). PB-Muse cell mobilization correlated with the volume of liver resection, suggesting that the PB-Muse cell number reflects the degree of liver injury. Given that the degree of PB-Muse cell mobilization was related to liver volume recovery, PB-Muse cells were suggested to contribute to liver regeneration, although this mechanism remains unclear.

Multilineage-differentiating stress-enduring cells alleviate atopic dermatitis-associated behaviors in mice

BackgroundPruritus is a recurring, long-lasting skin disease with few effective treatments. Many patients have unsatisfactory responses to currently available antipruritic treatments, and effective therapeutics are urgently needed to relieve symptoms. A previous study reported that mesenchymal stem cell (MSC)-mediated immune regulation could be used to treat skin inflammatory diseases. Multilineage-differentiating stress-enduring (Muse) cells are a new type of pluripotent stem cell that may also have the potential to treat inflammatory skin diseases.MethodsMuse cells were isolated from human bone marrow-derived MSCs (BMSCs) via the 8-h longterm trypsin incubation (LTT) method. Repeated use of 2,4-dinitrofluorobenzene (DNFB) induced atopic dermatitis (AD) in a mouse model. Immunofluorescence, behavior recording, and image analysis were used to evaluate the therapeutic effect of subcutaneous Muse cell injection. Real-time quantitative polymerase chain reaction (qPCR) was used to measure the expression of inflammatory factors. In vitro, wound healing and cell proliferation experiments were used to examine the effect of Muse cell supernatant on keratinocytes.ResultsOur results showed that subcutaneous injection of Muse cells after AD model induction significantly alleviated scratching behavior in mice. The evaluation of dermatitis and photos of damaged skin on the back of the neck revealed that Muse cells reduced dermatitis, playing an active role in healing the damaged skin. The activation of spinal glial cells and scratching behavior were also reduced by Muse cell injection. In addition, we also showed that the expression levels of the inflammatory factors interleukin (IL)-6, IL-17α, and IL-33 in both the spinal cord and skin were suppressed by Muse cells. Furthermore, Muse cells not only exerted anti-inflammatory effects on lipopolysaccharide (LPS)-induced human HaCat cells but also promoted wound healing and keratinocyte proliferation.ConclusionsIn vivo, Muse cells could alleviate scratching symptoms, reduce epidermal inflammation, and promote wound healing. In vitro, Muse cells could also promote the migration and proliferation of keratinocytes. In summary, Muse cells may become a new therapeutic agent for the treatment of AD.

Intravenous injection of human multilineage-differentiating stress-enduring cells alleviates mouse severe acute pancreatitis without immunosuppressants.

We examined the effect of intravenously injected human multilineage-differentiating stress-enduring (Muse) cells, non-tumorigenic endogenous reparative stem cells already used in clinical trials, on a severe acute pancreatitis (SAP) mouse model without immunosuppressants. Human Muse cells (1.0 × 105 cells) collected from mesenchymal stem cells (MSCs) as SSEA-3(+) were injected into a C57BL/6 mouse model via the jugular vein 6h after SAP-induction with taurocholate. The control group received saline or the same number of SSEA-3(-)-non-Muse MSCs. Edematous parameters, F4/80(+) macrophage infiltration and terminal deoxynucleotidyl transferase dUTP nick-end labeling positivity was the lowest and the number of proliferating endogenous pancreatic progenitors (CK18(+)/Ki67(+) cells) the highest in the Muse group among the three groups, with statistical significance, at 72h. An enzyme-linked immunosorbent assay and quantitative polymerase chain reaction demonstrated that in vitro production of VEGF, HGF, IGF-1, and MMP-2, which are relevant to tissue protection, anti-inflammation, and anti-fibrosis, were higher in Muse cells than in non-Muse MSCs, particularly when cells were cultured in SAP mouse serum. Consistently, the pancreas of animals in the Muse group contained higher amounts of those factors according to Western blotting at 18h than that in the non-Muse MSCs and control groups. Intravenous injection of human Muse cells was suggested to be effective for attenuating edema, inflammation and apoptosis in the acute phase of SAP.

Multilineage-differentiating Stress-enduring (MUSE) Cells in Orthobiologics: Are they the Future?

Multilineage-differentiating stress-enduring (MUSE) cells are non-tumorigenic pluripotent stem cells with endogenous reparative properties. These cells have a very powerful ability to adapt to global environment changes and are thus stress-tolerant cells. Interestingly, MUSE cells can differentiate into cells representative of all three germ layers. There has been a number of studies demonstrating its powerful regenerative power in several disorders: type-1 diabetes mellitus, myocardial infarction, stroke, glomerular-related kidney diseases, chronic liver failure, and ischemia-reperfusion lung injury. Recent data have also suggested that MUSE cells have significant repair properties for osteochondral lesions. The present article will review what are MUSE cells and how they work, the application of these cells into different disorders, and the studies up-to-date regarding MUSE cells in orthobiologic. Keywords: Muse cells, stem cells, regenerative, regeneration.

The evaluation of the safety and efficacy of intravenously administered allogeneic multilineage-differentiating stress-enduring cells in a swine hepatectomy model.

Multilineage-differentiating stress-enduring (Muse) cells are non-tumorigenic endogenous pluripotent-like cells residing in the bone marrow that exert a tissue reparative effect by replacing damaged/apoptotic cells through spontaneous differentiation into tissue-constituent cells. Post-hepatectomy liver failure (PHLF) is a potentially fatal complication. The main purpose of this study was to evaluate the safety and efficiency of allogeneic Muse cell administration via the portal vein in a swine model of PHLF. Swine Muse cells, collected from swine bone marrow-mesenchymal stem cells (MSCs) as SSEA-3(+) cells, were examined for their characteristics. Then, 1 × 107 allogeneic-Muse cells and allogeneic-MSCs and vehicle were injected via the portal vein in a 70% hepatectomy swine model. Swine Muse cells exhibited characteristics comparable to previously reported human Muse cells. Compared to the MSC and vehicle groups, the Muse group showed specific homing of the administered cells into the liver, resulting in improvements in the control of hyperbilirubinemia (P = 0.04), prothrombin international normalized ratio (P = 0.05), and suppression of focal necrosis (P = 0.04). Integrated Muse cells differentiated spontaneously into hepatocyte marker-positive cells. Allogeneic Muse cell administration may provide a reparative effect and functional recovery in a 70% hepatectomy swine model and thus may contribute to the treatment of PHLF.

Intravenously Transplanted Human Multilineage-Differentiating Stress-Enduring Cells Afford Brain Repair in a Mouse Lacunar Stroke Model.

Background and Purpose- Multilineage-differentiating stress-enduring cells are endogenous nontumorigenic reparative pluripotent-like stem cells found in bone marrow, peripheral blood, and connective tissues. Topically administered human multilineage-differentiating stress-enduring cells into rat/mouse stroke models differentiated into neural cells and promoted clinically relevant functional recovery. However, critical questions on the appropriate timing and dose, and safety of the less invasive intravenous administration of clinical-grade multilineage-differentiating stress-enduring cell-based product CL2020 remain unanswered. Methods- Using an immunodeficient mouse lacunar model, CL2020 was administered via the cervical vein in different doses (high dose=5×104 cells/body; medium dose=1×104 cells/body; low dose=5×103 cells/body) at subacute phase (≈9 days after onset) and chronic phase (≈30 days). Cylinder test, depletion of human cells by diphtheria toxin administration, immunohistochemistry, and human specific-genome detection were performed. Results- Tumorigenesis and adverse effects were not detected for up to 22 weeks. The high-dose group displayed significant functional recovery compared with the vehicle group in cylinder test in subacute-phase-treated and chronic-phase-treated animals after 6 weeks and 8 weeks post-injection, respectively. In the high-dose group of subacute-phase-treated animals, robust and stable recovery in cylinder test persisted up to 22 weeks compared with the vehicle group. In both groups, intraperitoneal injection of diphtheria toxin abrogated the functional recovery. Anti-human mitochondria revealed CL2020 distributed mainly in the peri-infarct area at 1, 10, and 22 weeks and expressed NeuN (neuronal nuclei)- and MAP-2 (microtubule-associated protein-2)-immunoreactivity. Conclusions- Intravenously administered CL2020 was safe, migrated to the peri-infarct area, and afforded functional recovery in experimental stroke.

Effects of acrylate/acrylamide polymers on the adhesion, growth and differentiation of Muse cells

Background. Acrylate/acrylamide copolymers have excellent optical properties and biocompatibility and are ideal biomaterials that have been widely used in tissue engineering. Multilineage-differentiating stress-enduring cells (Muse cells) are a specific subset of mesenchymal stem cells that have an excellent potential for the regenerative medicine. Objective. This study was designed to investigate the effects of acrylate/acrylamide copolymers on the adhesion, proliferation and pluripotent-like properties of Muse cells, which were derived from normal human dermal fibroblasts by long-term trypsin incubation. Methods. In an initial experiment, Muse cells were seeded on primary microarrays containing micro-spots of 275 different mixtures of acrylate/acrylamide. Each mixture was composed of two of 11 different monomers in various proportions, and was replicated in four micro-spots each. According to the adhesion and growth characteristics of Muse cells on those substrates, specific polymer candidates for Muse cells were selected and secondary microarrays were prepared. We then observed the effects of those specific polymer candidates on the adherence, proliferation and differentiation of Muse cells and suitable candidates for their optimal culture were identified. Results. According to the adhesion and growth patterns of Muse cells on the primary microarrays, ten suitable mixtures of acrylate/acrylamide copolymers were identified. Muse cells grew well on six of those combinations and around the four other combinations of those polymer mixtures. Muse cells cultured on three of those combinations proliferated and differentiated into long spindle-shaped cells that looked like fibroblasts, while Muse cells cultured on one combination formed clusters that were ring-shaped. Muse cells cultured on some of those combinations of acrylate/acrylamide proliferated and formed clusters that appeared to be very healthy, whereas Muse cells cultured on other combinations formed clusters that expanded outwards. Conclusions. These results identified a polymer combination that was optimum for the adhesion, proliferation and maintenance of Muse cells in an undifferentiated state.

Human Multilineage-differentiating Stress-Enduring Cells Exert Pleiotropic Effects to Ameliorate Acute Lung Ischemia–Reperfusion Injury in a Rat Model

Posttransplantation lung ischemia–reperfusion (IR) injuries affect both patient survival and graft function. In this study, we evaluated the protective effects of infused human multilineage-differentiating stress-enduring (Muse) cells, a novel, easily harvested type of nontumorigenic endogenous reparative stem cell, against acute IR lung injury in a rat model. After a 2-h warm IR injury induction in a left rat lung, human Muse cells, human mesenchymal stem cells (MSCs), and vehicle were injected via the left pulmonary artery after reperfusion. Functionality, histological findings, and protein expression were subsequently assessed in the injured lung. In vitro, we also compared human Muse cells with human MSCs in terms of migration abilities and the secretory properties of protective substances. The arterial oxygen partial pressure to fractional inspired oxygen ratio, alveolar-arterial oxygen gradient, left lung compliance, and histological injury score on hematoxylin–eosin sections were significantly better in the Muse group relative to the MSC and vehicle groups. Compared to MSCs, human Muse cells homed more efficiently to the injured lung, where they suppressed the apoptosis and stimulated proliferation of host alveolar cells. Human Muse cells also migrated to serum from lung-injured model rats and produced beneficial substances (keratinocyte growth factor [KGF], hepatocyte growth factor, angiopoietin-1, and prostaglandin E2) in vitro. Western blot of lung tissue confirmed high expression of KGF and their target molecules (interleukin-6, protein kinase B, and B-cell lymphoma-2) in the Muse group. Thus, Muse cells efficiently ameliorated lung IR injury via pleiotropic effects in a rat model. These findings support further investigation on the use of human Muse cells for lung IR injury.

Intravenously injected human multilineage-differentiating stress-enduring cells selectively engraft into mouse aortic aneurysms and attenuate dilatation by differentiating into multiple cell types

ObjectivesAortic aneurysms result from the degradation of multiple components represented by endothelial cells, vascular smooth muscle cells, and elastic fibers. Cells that can replenish these components are desirable for cell-based therapy. Intravenously injected multilineage-differentiating stress-enduring (Muse) cells, endogenous nontumorigenic pluripotent-like stem cells, reportedly integrate into the damaged site and repair the tissue through spontaneous differentiation into tissue-compatible cells. We evaluated the therapeutic efficacy of Muse cells in a murine aortic aneurysm model. MethodsHuman bone marrow Muse cells, isolated as stage-specific embryonic antigen-3+ from bone marrow mesenchymal stem cells, or non-Muse cells (stage-specific embryonic antigen-3- cells in mesenchymal stem cells), bone marrow mesenchymal stem cells, or vehicle was intravenously injected at day 0, day 7, and 2 weeks (20,000 cells/injection) after inducing aortic aneurysms by periaortic incubation of CaCl2 and elastase in severe combined immunodeficient mice. ResultsAt 8 weeks, infusion of human Muse cells attenuated aneurysm dilation, and the aneurysmal size in the Muse group corresponded to approximately 62.5%, 55.6%, and 45.6% in the non-Muse, mesenchymal stem cell, and vehicle groups, respectively. Multiphoton laser confocal microscopy revealed that infused Muse cells migrated into aneurysmal tissue from the adventitial side and penetrated toward the luminal side. Histologic analysis demonstrated robust preservation of elastic fibers and spontaneous differentiation into endothelial cells and vascular smooth muscle cells. ConclusionsAfter intravenous injection, Muse cells homed and expanded to the aneurysm from the adventitial side. Subsequently, Muse cells differentiated spontaneously into vascular smooth muscle cells and endothelial cells, and elastic fibers were preserved. These Muse cell features together led to substantial attenuation of aneurysmal dilation.

A partition-type tubular scaffold loaded with PDGF-releasing microspheres for spinal cord repair facilitates the directional migration and growth of cells.

The best tissue-engineered spinal cord grafts not only match the structural characteristics of the spinal cord but also allow the seed cells to grow and function in situ. Platelet-derived growth factor (PDGF) has been shown to promote the migration of bone marrow stromal cells; however, cytokines need to be released at a steady rate to maintain a stable concentration in vivo. Therefore, new methods are needed to maintain an optimal concentration of cytokines over an extended period of time to effectively promote seed cell localization, proliferation and differentiation. In the present study, a partition-type tubular scaffold matching the anatomical features of the thoracic 8-10 spinal cord of the rat was fabricated using chitosan and then subsequently loaded with chitosan-encapsulated PDGF-BB microspheres (PDGF-MSs). The PDGF-MS-containing scaffold was then examined in vitro for sustained-release capacity, biocompatibility, and its effect on neural progenitor cells differentiated in vitro from multilineage-differentiating stress-enduring cells (MUSE-NPCs). We found that pre-freezing for 2 hours at -20°C significantly increased the yield of partition-type tubular scaffolds, and 30 μL of 25% glutaraldehyde ensured optimal crosslinking of PDGF-MSs. The resulting PDGF-MSs cumulatively released 52% of the PDGF-BB at 4 weeks in vitro without burst release. The PDGF-MS-containing tubular scaffold showed suitable biocompatibility towards MUSE-NPCs and could promote the directional migration and growth of these cells. These findings indicate that the combination of a partition-type tubular scaffold, PDGF-MSs and MUSE-NPCs may be a promising model for the fabrication of tissue-engineered spinal cord grafts.

A MUSE for Skin Regeneration

With a rise in the prevalence of chronic wounds and other soft tissue defects, there is an urgent need to regenerate skin. Multilineage-differentiating stress-enduring cells were identified as distinct pluripotent stem cells in mesenchymal cell populations in humans. New research demonstrates the ability to effectively differentiate multilineage-differentiating stress-enduring cells into fibroblasts and keratinocytes for skin reconstitution.

The Potential of Muse Cells for Regenerative Medicine of Skin: Procedures to Reconstitute Skin with Muse Cell-Derived Keratinocytes, Fibroblasts, and Melanocytes

The Potential of Muse Cells for Regenerative Medicine of Skin: Procedures to Reconstitute Skin with Muse Cell-Derived Keratinocytes, Fibroblasts, and Melanocytes