Immunomodulatory capacity of the local mesenchymal stem cells transplantation after severe skeletal muscle injury in female rats

Effects of Adjunct Antifibrotic Treatment within a Regenerative Rehabilitation Paradigm for Volumetric Muscle Loss

The use of a rehabilitation approach that promotes regeneration has the potential to improve the efficacy of pro-regenerative therapies and maximize functional outcomes in the treatment of volumetric muscle loss (VML). An adjunct antifibrotic treatment could further enhance functional gains by reducing fibrotic scarring. This study aimed to evaluate the potential synergistic effects of losartan, an antifibrotic pharmaceutical, paired with a voluntary wheel running rehabilitation strategy to enhance a minced muscle graft (MMG) pro-regenerative therapy in a rodent model of VML. The animals were randomly assigned into four groups: (1) antifibrotic with rehabilitation, (2) antifibrotic without rehabilitation, (3) vehicle treatment with rehabilitation, and (4) vehicle treatment without rehabilitation. At 56 days, the neuromuscular function was assessed, and muscles were collected for histological and molecular analysis. Surprisingly, we found that the losartan treatment decreased muscle function in MMG-treated VML injuries by 56 days, while the voluntary wheel running elicited no effect. Histologic and molecular analysis revealed that losartan treatment did not reduce fibrosis. These findings suggest that losartan treatment as an adjunct therapy to a regenerative rehabilitation strategy negatively impacts muscular function and fails to promote myogenesis following VML injury. There still remains a clinical need to develop a regenerative rehabilitation treatment strategy for traumatic skeletal muscle injuries. Future studies should consider optimizing the timing and duration of adjunct antifibrotic treatments to maximize functional outcomes in VML injuries.

Intravenous Mesenchymal Stem Cell Administration Modulates Monocytes/Macrophages and Ameliorates Asthmatic Airway Inflammation in a Murine Asthma Model

Although asthma is a common chronic airway disease that responds well to anti-inflammatory agents, some patients with asthma are unresponsive to conventional treatment. Mesenchymal stem cells (MSCs) have therapeutic potential for the treatment of inflammatory diseases owing to their immunomodulatory properties. However, the target cells of MSCs are not yet clearly known. This study aimed to determine the effect of human umbilical cord-derived MSCs (hUC-MSCs) on asthmatic lungs by modulating innate immune cells and effector T cells using a murine asthmatic model. Intravenously administered hUC-MSCs reduced airway resistance, mucus production, and inflammation in the murine asthma model. hUC-MSCs attenuated not only T helper (Th) 2 cells and Th17 cells but also augmented regulatory T cells (Tregs). As for innate lymphoid cells (ILC), hUC-MSCs effectively suppressed ILC2s by downregulating master regulators of ILC2s, such as Gata3 and Tcf7. Finally, regarding lung macrophages, hUC-MSCs reduced the total number of macrophages, particularly the proportion of the enhanced monocyte-derived macrophage population. In a closer examination of monocyte-derived macrophages, hUC-MSCs reduced the M2a and M2c populations. In conclusion, hUC-MSCs can be considered as a potential anti- asthmatic treatment given their therapeutic effect on the asthmatic airway inflammation in a murine asthma model by modulating innate immune cells, such as ILC2s, M2a, and M2c macrophages, as well as affecting Tregs and effector T cells.

Comparison of Muscle Regeneration after BMSC-Conditioned Medium, Syngeneic, or Allogeneic BMSC Injection

For many years optimal treatment for dysfunctional skeletal muscle characterized, for example, by impaired or limited regeneration, has been searched. Among the crucial factors enabling its development is finding the appropriate source of cells, which could participate in tissue reconstruction or serve as an immunomodulating agent (limiting immune response as well as fibrosis, that is, connective tissue formation), after transplantation to regenerating muscles. MSCs, including those derived from bone marrow, are considered for such applications in terms of their immunomodulatory properties, as their naive myogenic potential is rather limited. Injection of autologous (syngeneic) or allogeneic BMSCs has been or is currently being tested and compared in many potential clinical treatments. In the present study, we verified which approach, that is, the transplantation of either syngeneic or allogeneic BMSCs or the injection of BMSC-conditioned medium, would be the most beneficial for skeletal muscle regeneration. To properly assess the influence of the tested treatments on the inflammation, the experiments were carried out using immunocompetent mice, which allowed us to observe immune response. Combined analysis of muscle histology, immune cell infiltration, and levels of selected chemokines, cytokines, and growth factors important for muscle regeneration, showed that muscle injection with BMSC-conditioned medium is the most beneficial strategy, as it resulted in reduced inflammation and fibrosis development, together with enhanced new fiber formation, which may be related to, i.e., elevated level of IGF-1. In contrast, transplantation of allogeneic BMSCs to injured muscles resulted in a visible increase in the immune response, which hindered regeneration by promoting connective tissue formation. In comparison, syngeneic BMSC injection, although not detrimental to muscle regeneration, did not result in such significant improvement as CM injection.

Embryonic stem cell-derived mesenchymal stem cells alleviate skeletal muscle injury induced by acute compartment syndrome

Background

Acute compartment syndrome (ACS), a well-known complication of musculoskeletal injury, results in muscle necrosis and cell death. Embryonic stem cell-derived mesenchymal stem cells (ESC-MSCs) have been shown to be a promising therapy for ACS. However, their effectiveness and potentially protective mechanism remain unknown. The present study was designed to investigate the efficacy and underlying mechanism of ESC-MSCs in ACS-induced skeletal muscle injury.

Method

A total of 168 male Sprague–Dawley (SD) rats underwent 2 h of intracompartmental pressure elevation by saline infusion into the anterior compartment of the left hindlimb to establish the ACS model. ESC-MSCs were differentiated from the human embryonic stem cell (ESC) line H9. A dose of 1.2 × 10⁶ of ESC-MSCs was intravenously injected during fasciotomy. Post-ACS assessments included skeletal edema index, serum indicators, histological analysis, apoptosis, fibrosis, regeneration, and functional recovery of skeletal muscle. Then, fluorescence microscopy was used to observe the distribution of labeled ESC-MSCs in vivo, and western blotting and immunofluorescence analyses were performed to examine macrophages infiltration in skeletal muscle. Finally, we used liposomal clodronate to deplete macrophages and reassess skeletal muscle injury in response to ESC-MSC therapy.

Result

ESC-MSCs significantly reduced systemic inflammatory responses, ACS-induced skeletal muscle edema, and cell apoptosis. In addition, ESC-MSCs inhibited skeletal muscle fibrosis and increased regeneration and functional recovery of skeletal muscle after ACS. The beneficial effects of ESC-MSCs on ACS-induced skeletal muscle injury were accompanied by a decrease in CD86-positive M1 macrophage polarization and an increase in CD206-positive M2 macrophage polarization. After depleting macrophages with liposomal clodronate, the beneficial effects of ESC-MSCs were attenuated.

Conclusion

Our findings suggest that embryonic stem cell-derived mesenchymal stem cells infusion could effectively alleviate ACS-induced skeletal muscle injury, in which the beneficial effects were related to the regulation of macrophages polarization.

Intratracheal administration of mesenchymal stem cells modulates lung macrophage polarization and exerts anti-asthmatic effects

Mesenchymal stem cells (MSCs) possess immunomodulatory properties that have therapeutic potential for the treatment of inflammatory diseases. This study investigates the effects of direct MSC administration on asthmatic airways. Umbilical cord MSCs (ucMSCs) were intratracheally administered to six-week-old female BALB/c mice sensitized and challenged with ovalbumin; airway hyperresponsiveness (AHR), analyses of airway inflammatory cells, lung histology, flow cytometry, and quantitative real-time PCR were performed. Furthermore, ex vivo and in vitro experiments were performed to assess the effects of ucMSC on M2 activation. Intratracheally administered ucMSCs decreased degree of airway resistance and the number of inflammatory cells such as T helper 2 (Th2) cells, type 2 innate lymphoid cells (ILC2), and macrophages in the murine asthma model. Particularly, MHCII and CD86 expression diminished in dendritic cells and alveolar macrophages (AMs) following ucMSC treatment. SiglecF⁺CD11c⁺CD11b^- AMs show a negative correlation with type II inflammatory cells including Th2 cells, ILC2, and eosinophils in asthmatic mice and were restored following intratracheal ucMSCs treatment. In addition, ucMSCs decreased the macrophage polarization to M2, particularly M2a. The expression levels of markers associated with M2 polarization and Th2 inflammation were also decreased. ucMSC reduced Il-12 and Tnfa expression as well as that of M2 markers such as Cd206 and Retnla ex vivo. Furthermore, the in vitro study using IL-4 treated macrophages confirmed that both direct and indirect MSC treatment significantly reduced the expression of Il-5 and Il-13. In conclusion, ucMSCs appear to suppress type II inflammation by regulating lung macrophages via soluble mediators.

The miR151 and miR5100 Transfected Bone Marrow Stromal Cells Increase Myoblast Fusion in IGFBP2 Dependent Manner

Background

Bone marrow stromal cells (BMSCs) form a perivascular cell population in the bone marrow. These cells do not present naïve myogenic potential. However, their myogenic identity could be induced experimentally in vitro or in vivo. In vivo, after transplantation into injured muscle, BMSCs rarely fused with myofibers. However, BMSC participation in myofiber reconstruction increased if they were modified by NICD or PAX3 overexpression. Nevertheless, BMSCs paracrine function could play a positive role in skeletal muscle regeneration. Previously, we showed that SDF-1 treatment and coculture with myofibers increased BMSC ability to reconstruct myofibers. We also noticed that SDF-1 treatment changed selected miRNAs expression, including miR151 and miR5100.

Methods

Mouse BMSCs were transfected with miR151 and miR5100 mimics and their proliferation, myogenic differentiation, and fusion with myoblasts were analyzed.

Results

We showed that miR151 and miR5100 played an important role in the regulation of BMSC proliferation and migration. Moreover, the presence of miR151 and miR5100 transfected BMSCs in co-cultures with human myoblasts increased their fusion. This effect was achieved in an IGFBP2 dependent manner.

Conclusions

Mouse BMSCs did not present naïve myogenic potential but secreted proteins could impact myogenic cell differentiation. miR151 and miR5100 transfection changed BMSC migration and IGFBP2 and MMP12 expression in BMSCs. miR151 and miR5100 transfected BMSCs increased myoblast fusion in vitro.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s12015-022-10350-y.

Mesenchymal Stem/Stromal Cells and Their Paracrine Activity-Immunomodulation Mechanisms and How to Influence the Therapeutic Potential

With high clinical interest to be applied in regenerative medicine, Mesenchymal Stem/Stromal Cells have been widely studied due to their multipotency, wide distribution, and relative ease of isolation and expansion in vitro. Their remarkable biological characteristics and high immunomodulatory influence have opened doors to the application of MSCs in many clinical settings. The therapeutic influence of these cells and the interaction with the immune system seems to occur both directly and through a paracrine route, with the production and secretion of soluble factors and extracellular vesicles. The complex mechanisms through which this influence takes place is not fully understood, but several functional manipulation techniques, such as cell engineering, priming, and preconditioning, have been developed. In this review, the knowledge about the immunoregulatory and immunomodulatory capacity of MSCs and their secretion products is revisited, with a special focus on the phenomena of migration and homing, direct cell action and paracrine activity. The techniques for homing improvement, cell modulation and conditioning prior to the application of paracrine factors were also explored. Finally, multiple assays where different approaches were applied with varying success were used as examples to justify their exploration.

Cellular and molecular modulation of rotator cuff muscle pathophysiology

Rotator cuff (RC) tendon tears are common shoulder injuries that result in irreversible and persistent degeneration of the associated muscles, which is characterized by severe inflammation, atrophy, fibrosis, and fatty infiltration. Although RC muscle degeneration strongly dictates the overall clinical outcomes, strategies to stimulate RC muscle regeneration have largely been overlooked to date. In this review, we highlight the current understanding of the cellular processes that coordinate muscle regeneration, and the roles of muscle resident cells, including immune cells, fibroadipogenic progenitors, and muscle satellite cells in the pathophysiologic regulation of RC muscles following injury. This review also provides perspectives for potential therapies to alleviate the hallmarks of RC muscle degeneration to address current limitations in postsurgical recovery.

Stem Cell and Macrophage Roles in Skeletal Muscle Regenerative Medicine

In severe muscle injury, skeletal muscle tissue structure and functionality can be repaired through the involvement of several cell types, such as muscle stem cells, and innate immune responses. However, the exact mechanisms behind muscle tissue regeneration, homeostasis, and plasticity are still under investigation, and the discovery of pathways and cell types involved in muscle repair can open the way for novel therapeutic approaches, such as cell-based therapies involving stem cells and peripheral blood mononucleate cells. Indeed, peripheral cell infusions are a new therapy for muscle healing, likely because autologous peripheral blood infusion at the site of injury might enhance innate immune responses, especially those driven by macrophages. In this review, we summarize current knowledge on functions of stem cells and macrophages in skeletal muscle repairs and their roles as components of a promising cell-based therapies for muscle repair and regeneration.

Current Strategies for the Regeneration of Skeletal Muscle Tissue

Traumatic injuries, tumor resections, and degenerative diseases can damage skeletal muscle and lead to functional impairment and severe disability. Skeletal muscle regeneration is a complex process that depends on various cell types, signaling molecules, architectural cues, and physicochemical properties to be successful. To promote muscle repair and regeneration, various strategies for skeletal muscle tissue engineering have been developed in the last decades. However, there is still a high demand for the development of new methods and materials that promote skeletal muscle repair and functional regeneration to bring approaches closer to therapies in the clinic that structurally and functionally repair muscle. The combination of stem cells, biomaterials, and biomolecules is used to induce skeletal muscle regeneration. In this review, we provide an overview of different cell types used to treat skeletal muscle injury, highlight current strategies in biomaterial-based approaches, the importance of topography for the successful creation of functional striated muscle fibers, and discuss novel methods for muscle regeneration and challenges for their future clinical implementation.

Mesenchymal Stromal Cells and Their Secretome: New Therapeutic Perspectives for Skeletal Muscle Regeneration

Mesenchymal stromal cells (MSCs) are multipotent cells found in different tissues: bone marrow, peripheral blood, adipose tissues, skeletal muscle, perinatal tissues, and dental pulp. MSCs are able to self-renew and to differentiate into multiple lineages, and they have been extensively used for cell therapy mostly owing to their anti-fibrotic and immunoregulatory properties that have been suggested to be at the basis for their regenerative capability. MSCs exert their effects by releasing a variety of biologically active molecules such as growth factors, chemokines, and cytokines, either as soluble proteins or enclosed in extracellular vesicles (EVs). Analyses of MSC-derived secretome and in particular studies on EVs are attracting great attention from a medical point of view due to their ability to mimic all the therapeutic effects produced by the MSCs (i.e., endogenous tissue repair and regulation of the immune system). MSC-EVs could be advantageous compared with the parental cells because of their specific cargo containing mRNAs, miRNAs, and proteins that can be biologically transferred to recipient cells. MSC-EV storage, transfer, and production are easier; and their administration is also safer than MSC therapy. The skeletal muscle is a very adaptive tissue, but its regenerative potential is altered during acute and chronic conditions. Recent works demonstrate that both MSCs and their secretome are able to help myofiber regeneration enhancing myogenesis and, interestingly, can be manipulated as a novel strategy for therapeutic interventions in muscular diseases like muscular dystrophies or atrophy. In particular, MSC-EVs represent promising candidates for cell free-based muscle regeneration. In this review, we aim to give a complete picture of the therapeutic properties and advantages of MSCs and their products (MSC-derived EVs and secreted factors) relevant for skeletal muscle regeneration in main muscular diseases.

Bone Marrow-Mesenchymal Stromal Cell Secretome as Conditioned Medium Relieves Experimental Skeletal Muscle Damage Induced by Ex Vivo Eccentric Contraction

Bone marrow-mesenchymal stem/stromal cells (MSCs) may offer promise for skeletal muscle repair/regeneration. Growing evidence suggests that the mechanisms underpinning the beneficial effects of such cells in muscle tissue reside in their ability to secrete bioactive molecules (secretome) with multiple actions. Hence, we examined the effects of MSC secretome as conditioned medium (MSC-CM) on ex vivo murine extensor digitorum longus muscle injured by forced eccentric contraction (EC). By combining morphological (light and confocal laser scanning microscopies) and electrophysiological analyses we demonstrated the capability of MSC-CM to attenuate EC-induced tissue structural damages and sarcolemnic functional properties’ modifications. MSC-CM was effective in protecting myofibers from apoptosis, as suggested by a reduced expression of pro-apoptotic markers, cytochrome c and activated caspase-3, along with an increase in the expression of pro-survival AKT factor. Notably, MSC-CM also reduced the EC-induced tissue redistribution and extension of telocytes/CD34⁺ stromal cells, distinctive cells proposed to play a “nursing” role for the muscle resident myogenic satellite cells (SCs), regarded as the main players of regeneration. Moreover, it affected SC functionality likely contributing to replenishment of the SC reservoir. This study provides the necessary groundwork for further investigation of the effects of MSC secretome in the setting of skeletal muscle injury and regenerative medicine.

The Role of Innate and Adaptive Immune Cells in Skeletal Muscle Regeneration

Skeletal muscle regeneration is highly dependent on the inflammatory response. A wide variety of innate and adaptive immune cells orchestrate the complex process of muscle repair. This review provides information about the various types of immune cells and biomolecules that have been shown to mediate muscle regeneration following injury and degenerative diseases. Recently developed cell and drug-based immunomodulatory strategies are highlighted. An improved understanding of the immune response to injured and diseased skeletal muscle will be essential for the development of therapeutic strategies.

Magnetization of mesenchymal stem cells using magnetic liposomes enhances their retention and immunomodulatory efficacy in mouse inflamed skeletal muscle

Sarcopenia, an age-related reduction in skeletal muscle mass and strength, is mainly caused by chronic inflammation. Because mesenchymal stem cells (MSCs) have the capacity to both promote myogenic cell differentiation and suppress inflammation, they are a promising candidate for sarcopenia treatment. In this study, to achieve the long-term retention of MSCs in skeletal muscle, we prepared magnetized MSCs using magnetic anionic liposome/atelocollagen complexes that we had previously developed, and evaluated their retention efficiency and immunomodulatory effects in mouse inflamed skeletal muscle. Mouse MSCs were efficiently magnetized by incubation with magnetic anionic liposome/atelocollagen complexes for 30 min under a magnetic field. The magnetized MSCs differentiated normally into osteoblasts and adipocytes. Additionally, non-magnetized MSCs and magnetized MSCs increased IL-6 and inducible nitric oxide synthase mRNA expression and decreased TNF-α and IL-1β mRNA expression in C2C12 mouse skeletal muscle myotubes through paracrine effects. Moreover, magnetized MSCs were significantly retained in cell culture plates and mouse skeletal muscle after their local injection in the presence of a magnetic field. Furthermore, magnetized MSCs significantly increased IL-6 and IL-10 mRNA expression and decreased TNF-α and IL-1β mRNA expression in inflamed skeletal muscle. These results suggest that magnetized MSCs may be useful for effective sarcopenia treatment.

Cell therapy to improve regeneration of skeletal muscle injuries

Diseases that jeopardize the musculoskeletal system and cause chronic impairment are prevalent throughout the Western world. In Germany alone, ~1.8 million patients suffer from these diseases annually, and medical expenses have been reported to reach 34.2bn Euros. Although musculoskeletal disorders are seldom fatal, they compromise quality of life and diminish functional capacity. For example, musculoskeletal disorders incur an annual loss of over 0.8 million workforce years to the German economy. Among these diseases, traumatic skeletal muscle injuries are especially problematic because they can occur owing to a variety of causes and are very challenging to treat. In contrast to chronic muscle diseases such as dystrophy, sarcopenia, or cachexia, traumatic muscle injuries inflict damage to localized muscle groups. Although minor muscle trauma heals without severe consequences, no reliable clinical strategy exists to prevent excessive fibrosis or fatty degeneration, both of which occur after severe traumatic injury and contribute to muscle degeneration and dysfunction. Of the many proposed strategies, cell-based approaches have shown the most promising results in numerous pre-clinical studies and have demonstrated success in the handful of clinical trials performed so far. A number of myogenic and non-myogenic cell types benefit muscle healing, either by directly participating in new tissue formation or by stimulating the endogenous processes of muscle repair. These cell types operate via distinct modes of action, and they demonstrate varying levels of feasibility for muscle regeneration depending, to an extent, on the muscle injury model used. While in some models the injury naturally resolves over time, other models have been developed to recapitulate the peculiarities of real-life injuries and therefore mimic the structural and functional impairment observed in humans. Existing limitations of cell therapy approaches include issues related to autologous harvesting, expansion and sorting protocols, optimal dosage, and viability after transplantation. Several clinical trials have been performed to treat skeletal muscle injuries using myogenic progenitor cells or multipotent stromal cells, with promising outcomes. Recent improvements in our understanding of cell behaviour and the mechanistic basis for their modes of action have led to a new paradigm in cell therapies where physical, chemical, and signalling cues presented through biomaterials can instruct cells and enhance their regenerative capacity. Altogether, these studies and experiences provide a positive outlook on future opportunities towards innovative cell-based solutions for treating traumatic muscle injuries-a so far unmet clinical need.

Transplanted human multipotent stromal cells reduce acute tongue fibrosis in rats

Background

Tongue fibrosis resulting from head and neck cancer, surgery, radiation, chemotherapy, or a combination thereof devastates one's quality of life. Therapeutic options are limited. Here we investigate human bone marrow-derived multipotent stromal cells (MSC) as a novel injectable treatment for post-injury tongue fibrosis.

Methods

MSCs were grown in culture. Eighteen athymic rats underwent unilateral partial glossectomy. After two weeks for scar formation, a single injection was performed in the tongue scar. Three treatment groups were studied: low and high concentration MSC, and control media injection. Tongues were harvested for evaluation at three weeks post-treatment.

Results

Dense fibrosis was achieved in control animals at five weeks. High concentration MSC reduced cross sectional scar burden (P = .007) and pathologic score for inflammation and fibrosis.

Conclusion

This study establishes the feasibility of a novel rodent tongue fibrosis model, and begins to assess the utility of human MSCs to reduce scar burden.

Level of Evidence

N/a.

Stem Cells for Skeletal Muscle Tissue Engineering

Volumetric muscle loss (VML) is a debilitating condition wherein muscle loss overwhelms the body's normal physiological repair mechanism. VML is particularly common among military service members who have sustained war injuries. Because of the high social and medical cost associated with VML and suboptimal current surgical treatments, there is great interest in developing better VML therapies. Skeletal muscle tissue engineering (SMTE) is a promising alternative to traditional VML surgical treatments that use autogenic tissue grafts, and rather uses isolated stem cells with myogenic potential to generate de novo skeletal muscle tissues to treat VML. Satellite cells are the native precursors to skeletal muscle tissue, and are thus the most commonly studied starting source for SMTE. However, satellite cells are difficult to isolate and purify, and it is presently unknown whether they would be a practical source in clinical SMTE applications. Alternative myogenic stem cells, including adipose-derived stem cells, bone marrow-derived mesenchymal stem cells, perivascular stem cells, umbilical cord mesenchymal stem cells, induced pluripotent stem cells, and embryonic stem cells, each have myogenic potential and have been identified as possible starting sources for SMTE, although they have yet to be studied in detail for this purpose. These alternative stem cell varieties offer unique advantages and disadvantages that are worth exploring further to advance the SMTE field toward highly functional, safe, and practical VML treatments. The following review summarizes the current state of satellite cell-based SMTE, details the properties and practical advantages of alternative myogenic stem cells, and offers guidance to tissue engineers on how alternative myogenic stem cells can be incorporated into SMTE research.

A Simple Method to Isolate and Expand Human Umbilical Cord Derived Mesenchymal Stem Cells: Using Explant Method and Umbilical Cord Blood Serum

Background and Objectives

Mesenchymal stem cells (MSCs) are multipotent stem cells that can be isolated from umbilical cords and are therapeutically used because of their ability to differentiate into various types of cells, in addition to their immunosuppressive and anti-inflammatory properties. Fetal bovine serum (FBS), considered as the standard additive when isolating and culturing MSCs, has a major limitation related to its animal origin. Here, we employed a simple and economically efficient protocol to isolate MSCs from human umbilical cord tissues without using digestive enzymes and replacing FBS with umbilical cord blood serum (CBS).

Methods and Results

MSCs were isolated by culturing umbilical cord pieces in CBS or FBS supplemented media. Expansion and proliferation kinetics of cells isolated by explant method in the presence of either FBS or CBS were measured, with morphology and multi-differentiation potential of expanded cells characterized by flow cytometry, RT-PCR, and immunofluorescence. MSCs maintained morphology, immunophenotyping, multi-differentiation potential, and self-renewal ability, with better proliferation rates for cells cultured in CBS compared to FBS supplement media.

Conclusions

We here present a simple, reliable and efficient method to isolate MSCs from umbilical cord tissues, where cells maintained proliferation, differentiation potential and immunophenotyping properties and could be efficiently expanded for clinical applications.

Long noncoding RNA DANCR regulates miR-1305-Smad 4 axis to promote chondrogenic differentiation of human synovium-derived mesenchymal stem cells

miRNAs have been reported to regulate cellular differentiation by modulating multiple signaling pathways. Long noncoding RNA (lnc RNA) DANCR was previously identified to be critical for the chondrogenesis of human synovium-derived mesenchymal stem cells (SMSC), however, the underlying molecular mechanism requires better understanding. Here, miRNA expression profiling in DANCR overexpressed in SMSCs identified significant down-regulation of miR-1305, which serves as a downstream target of DANCR. Notably, miR-1305 overexpression reversed DANCR-induced cell proliferation and chondrogenic differentiation of SMSCs, which suggested that miR-1305 antagonized the function of DANCR. Mechanistically, highly expressed miR-1305 resulted in the decreased expression of the TGF-β pathway member Smad4, and inhibition of miR-1305 enhanced the expression level of Smad4. Depletion of Smad4 suppressed the promotion of DANCR in cell proliferation and chondrogenesis of SMSCs. Collectively, our results characterized miR-1305-Smad4 axis as a major downstream functional mechanism of lncRNA DANCR in promoting the chondrogenesis in SMSCs.