Mesenchymal stem cell-derived factors: Immuno-modulatory effects and therapeutic potential

Anti-inflammatory Effects of Mesenchymal Stem Cells and Their Secretomes in Pneumonia

Mesenchymal stem cells (MSCs) are multipotent progenitor cells that play crucial roles in the microenvironment of injured tissues. The potential therapeutics of MSCs have attracted extensive attention for several diseases such as acute respiratory distress syndrome (ARDS) and novel coronavirus disease 2019 (COVID-19) pneumonia. MSC-extracellular vesicles have been isolated from MSC-conditioned media (MSC-CM) with similar functional effects as parent MSCs. The therapeutic role of MSCs can be achieved through the balance between the inflammatory and regenerative microenvironments. Clinical settings of MSCs and their extracellular vesicles remain promising for many diseases, such as ARDS and pneumonia. However, their clinical applications remain limited due to the cost of growing and storage facilities of MSCs with a lack of standardized MSC-CM. This review highlights the proposed role of MSCs in pulmonary diseases and discusses the recent advances of MSC application for pneumonia and other lung disorders.

Impact of type 2 diabetes mellitus on the immunoregulatory characteristics of adipose tissue-derived mesenchymal stem cells

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder associated with several complications. Adipose tissue-derived mesenchymal stem cells (AT-MSCs) represent an emerging type of MSCs with high plasticity and immunoregulatory capabilities and are useful for treating inflammation-related disorders such as T2DM. However, the pathogenic microenvironment of T2DM may affect their therapeutic potential. We aimed to examine the impact of the diabetic milieu on the immunomodulatory/anti-inflammatory potential of AT-MSCs.

METHODS

We assessed the proliferation potential, cell surface expression of MSC-characteristic markers and immunomodulatory markers, along with the gene expression and protein secretion of pro-inflammatory and anti-inflammatory cytokines and adipokines in AT-MSCs derived from T2DM patients (dAT-MSCs) vs. those derived from non-diabetic volunteers (ndAT-MSCs). Furthermore, we evaluated the IFN-γ priming effect on both groups.

RESULTS

Our data revealed comparable proliferative activities in both groups. Flow cytometric analysis results showed a lower expression of CD200 and CD276 on dAT-MSCs vs. ndAT-MSCs. qPCR demonstrated upregulation of IL-1β associated with a downregulation of IL-1RN in dAT-MSCs vs. ndAT-MSCs. IFN-γ priming induced an elevation in CD274 expression associated with IDO1 and ILRN overexpression and IL-1β downregulation in both groups. ELISA analysis uncovered elevated levels of secreted IL-1β, TNF, and visfatin/NAMPT in dAT-MSCs, whereas IL-1RA and IDO levels were reduced. ELISA results were also evident in the secretome of dAT-MSCs upon IFN-γ priming.

CONCLUSIONS

This study suggests that the T2DM milieu alters the immunomodulatory characteristics of AT-MSCs with a shift towards a proinflammatory phenotype which may restrain their autologous therapeutic use. Furthermore, our findings indicate that IFN-γ priming could be a useful strategy for enhancing dAT-MSC anti-inflammatory potential.

Apoptotic mesenchymal stromal cells support osteoclastogenesis while inhibiting multinucleated giant cells formation in vitro

In bone regeneration induced by the combination of mesenchymal stromal cells (MSCs) and calcium-phosphate (CaP) materials, osteoclasts emerge as a pivotal cell linking inflammation and bone formation. Favorable outcomes are observed despite short-term engraftments of implanted MSCs, highlighting their major paracrine function and the possible implication of cell death in modulating their secretions. In this work, we focused on the communication from MSCs towards osteoclasts-like cells in vitro. MSCs seeded on a CaP biomaterial or undergoing induced apoptosis produced a conditioned media favoring the development of osteoclasts from human CD14+ monocytes. On the contrary, MSCs’ apoptotic secretion inhibited the development of inflammatory multinucleated giant cells formed after IL-4 stimulation. Components of MSCs’ secretome before and after apoptotic stress were compared using mass spectrometry-based quantitative proteomics and a complementary immunoassay for major cytokines. CXCR-1 and CXCR-2 ligands, primarily IL-8/CXCL-8 but also the growth-regulated proteins CXCL-1, -2 or -3, were suggested as the major players of MSCs’ pro-osteoclastic effect. These findings support the hypothesis that osteoclasts are key players in bone regeneration and suggest that apoptosis plays an important role in MSCs’ effectiveness.

Molecular Mechanisms Responsible for Mesenchymal Stem Cell-Based Treatment of Viral Diseases

Mesenchymal stem cells (MSCs) are adult, immunomodulatory stem cells which reside in almost all postnatal tissues. Viral antigens and damage-associated molecular patterns released from injured and infected cells activate MSCs, which elicit strong antiviral immune response. MSC-sourced interferons and inflammatory cytokines modulate the cytotoxicity of NK cells and CTLs, enhance the antigen-presentation properties of DCs and macrophages, regulate cytokine synthesis in CD4+ T helper cells and promote antibody production in B cells. After the elimination of viral pathogens, MSCs produce immunoregulatory cytokines and trophic factors, prevent the over-activation of immune cells and promote tissue repair and regeneration. In this review article, we summarize the current knowledge on the molecular mechanisms that are responsible for the MSC-dependent elimination of virus-infected cells, and we emphasize the therapeutic potential of MSCs and their secretomes in the treatment of viral diseases.

Mesenchymal stem/stromal cells as a valuable source for the treatment of immune-mediated disorders

Over recent years, mesenchymal stem/stromal cells (MSCs) and their potential biomedical applications have received much attention from the global scientific community in an increasing manner. Firstly, MSCs were successfully isolated from human bone marrow (BM), but in the next steps, they were also extracted from other sources, mostly from the umbilical cord (UC) and adipose tissue (AT). The International Society for Cellular Therapy (ISCT) has suggested minimum criteria to identify and characterize MSCs as follows: plastic adherence, surface expression of CD73, D90, CD105 in the lack of expression of CD14, CD34, CD45, and human leucocyte antigen-DR (HLA-DR), and also the capability to differentiate to multiple cell types including adipocyte, chondrocyte, or osteoblast in vitro depends on culture conditions. However, these distinct properties, including self-renewability, multipotency, and easy accessibility are just one side of the coin; another side is their huge secretome which is comprised of hundreds of mediators, cytokines, and signaling molecules and can effectively modulate the inflammatory responses and control the infiltration process that finally leads to a regulated tissue repair/healing or regeneration process. MSC-mediated immunomodulation is a direct result of a harmonic synergy of MSC-released signaling molecules (i.e., mediators, cytokines, and chemokines), the reaction of immune cells and other target cells to those molecules, and also feedback in the MSC-molecule-target cell axis. These features make MSCs a respectable and eligible therapeutic candidate to be evaluated in immune-mediated disorders, such as graft versus host diseases (GVHD), multiple sclerosis (MS), Crohn's disease (CD), and osteoarthritis (OA), and even in immune-dysregulating infectious diseases such as the novel coronavirus disease 2019 (COVID-19). This paper discussed the therapeutic applications of MSC secretome and its biomedical aspects related to immune-mediated conditions. Sources for MSC extraction, their migration and homing properties, therapeutic molecules released by MSCs, and the pathways and molecular mechanisms possibly involved in the exceptional immunoregulatory competence of MSCs were discussed. Besides, the novel discoveries and recent findings on immunomodulatory plasticity of MSCs, clinical applications, and the methods required for their use as an effective therapeutic option in patients with immune-mediated/immune-dysregulating diseases were highlighted.

Comparisons of Extracellular Vesicles from Human Epidural Fat-Derived Mesenchymal Stem Cells and Fibroblast Cells

Extracellular vesicles (EVs) are generated and secreted by cells into the circulatory system. Stem cell-derived EVs have a therapeutic effect similar to that of stem cells and are considered an alternative method for cell therapy. Accordingly, research on the characteristics of EVs is emerging. EVs were isolated from human epidural fat-derived mesenchymal stem cells (MSCs) and human fibroblast culture media by ultracentrifugation. The characterization of EVs involved the typical evaluation of cluster of differentiation (CD antigens) marker expression by fluorescence-activated cell sorting, size analysis with dynamic laser scattering, and morphology analysis with transmission electron microscopy. Lastly, the secreted levels of cytokines and chemokines in EVs were determined by a cytokine assay. The isolated EVs had a typical size of approximately 30–200 nm, and the surface proteins CD9 and CD81 were expressed on human epidural fat MSCs and human fibroblast cells. The secreted levels of cytokines and chemokines were compared between human epidural fat MSC-derived EVs and human fibroblast-derived EVs. Human epidural fat MSC-derived EVs showed anti-inflammatory effects and promoted macrophage polarization. In this study, we demonstrated for the first time that human epidural fat MSC-derived EVs exhibit inflammatory suppressive potency relative to human fibroblast-derived EVs, which may be useful for the treatment of inflammation-related diseases.

The Cross-Talk between Mesenchymal Stem Cells and Immune Cells in Tissue Repair and Regeneration

Mesenchymal stem cells (MSCs) are self-renewable, rapidly proliferating, multipotent stem cells which reside in almost all post-natal tissues. MSCs possess potent immunoregulatory properties and, in juxtacrine and paracrine manner, modulate phenotype and function of all immune cells that participate in tissue repair and regeneration. Additionally, MSCs produce various pro-angiogenic factors and promote neo-vascularization in healing tissues, contributing to their enhanced repair and regeneration. In this review article, we summarized current knowledge about molecular mechanisms that regulate the crosstalk between MSCs and immune cells in tissue repair and regeneration.

Apoptosis: A friend or foe in mesenchymal stem cell-based immunosuppression

Mesenchymal stem cells (MSC) are adult stem cells which reside in almost all postnatal tissue where, in juxtacrine and paracrine manner, regulate phenotype and function of immune cells, maintain tissue homeostasis, attenuate on-going inflammation and promote repair and regeneration of injured tissues. Due to their capacity to suppress detrimental immune response, MSC have been considered as potentially new therapeutic agents in the treatment of autoimmune and inflammatory diseases. It was recently revealed that apoptosis may increase anti-inflammatory properties of MSC by enhancing their capacity to induce generation of immunosuppressive phenotype in macrophages and dendritic cells. Upon phagocytosis, apoptotic MSC induce generation of immunosuppressive phenotype in monocytes/macrophages and promote production of anti-inflammatory cytokines and growth factors that attenuate inflammation and facilitate repair and regeneration of injured tissues. Importantly, immunomodulation mediated by apoptotic MSC was either similar or even better than immunomodulation accomplished by viable MSC. In contrast to viable MSC, which obtain either pro- or anti-inflammatory phenotype upon engraftment in different tissue microenvironments, apoptotic MSC were not subject to changes in their immunomodulatory characteristics upon diverse stimuli, indicating their potential for clinical use. In this chapter, we summarized current knowledge about beneficial effects of apoptotic MSC in the suppression of detrimental local and systemic immune response, and we emphasized their therapeutic potential in the treatment of inflammatory diseases.

Pluripotency and immunomodulatory signatures of canine induced pluripotent stem cell-derived mesenchymal stromal cells are similar to harvested mesenchymal stromal cells

With a view towards harnessing the therapeutic potential of canine mesenchymal stromal cells (cMSCs) as modulators of inflammation and the immune response, and to avoid the issues of the variable quality and quantity of harvested cMSCs, we examined the immunomodulatory properties of cMSCs derived from canine induced pluripotent stem cells (ciMSCs), and compared them to cMSCs harvested from adipose tissue (cAT-MSC) and bone marrow (cBM-MSC). A combination of deep sequencing and quantitative RT-PCR of the ciMSC transcriptome confirmed that ciMSCs express more genes in common with cBM-MSCs and cAT-MSCs than with the ciPSCs from which they were derived. Both ciMSCs and harvested cMSCs express a range of pluripotency factors in common with the ciPSCs including NANOG, POU5F1 (OCT-4), SOX-2, KLF-4, LIN-28A, MYC, LIF, LIFR, and TERT. However, ESRRB and PRDM-14, both factors associated with naïve, rather than primed, pluripotency were expressed only in the ciPSCs. CXCR-4, which is essential for the homing of MSCs to sites of inflammation, is also detectable in ciMSCs, cAT- and cBM-MSCs, but not ciPSCs. ciMSCs constitutively express the immunomodulatory factors iNOS, GAL-9, TGF-β1, PTGER-2α and VEGF, and the pro-inflammatory mediators COX-2, IL-1β and IL-8. When stimulated with the canine pro-inflammatory cytokines tumor necrosis factor-α (cTNF-α), interferon-γ (cIFN-γ), or a combination of both, ciMSCs upregulated their expression of IDO, iNOS, GAL-9, HGF, TGF-β1, PTGER-2α, VEGF, COX-2, IL-1β and IL-8. When co-cultured with mitogen-stimulated lymphocytes, ciMSCs downregulated their expression of iNOS, HGF, TGF-β1 and PTGER-2α, while increasing their expression of COX-2, IDO and IL-1β. Taken together, these findings suggest that ciMSCs possess similar immunomodulatory capabilities as harvested cMSCs and support further investigation into their potential use for the management of canine immune-mediated and inflammatory disorders.

Mesenchymal Stem Cell-Derived Exosomes as New Remedy for the Treatment of Neurocognitive Disorders

Mesenchymal stem cell (MSC)-derived exosomes (MSC-Exo) are nano-sized extracellular vesicles enriched with MSC-sourced neuroprotective and immunomodulatory microRNAs, neural growth factors, and anti-inflammatory cytokines, which attenuate neuro-inflammation, promote neo-vascularization, induce neurogenesis, and reduce apoptotic loss of neural cells. Accordingly, a large number of experimental studies demonstrated MSC-Exo-dependent improvement of cognitive impairment in experimental animals. In this review article, we summarized current knowledge about molecular and cellular mechanisms that were responsible for MSC-Exo-based restoration of cognitive function, emphasizing therapeutic potential of MSC-Exos in the treatment of neurocognitive disorders.

Therapeutic potential of mesenchymal stem cell-derived extracellular vesicles as novel cell-free therapy for treatment of autoimmune disorders

Over the past decades, new light has been shed on the efficiency of Mesenchymal Stem Cells (MSCs) in the treatment of autoimmune diseases. The therapeutic functions of MSCs partly stem from their well-recognized ability to efficiently modulate immune responses and it is well substantiated that MSC secretory components, in particular extracellular vesicles (EVs), play a critical role in this immunomodulation. In fact, almost any cell type can generate and release EVs under both pathological and physiological conditions and these nano-sized particles are believed to greatly contribute to homeostasis and cell-cell communication through transportation of a wide variety of biomolecules including nucleic acid, signaling lipids, regulatory proteins, transcription factors, cytokines, and growth factors. Lamentably, despite exhibiting promising results in both animal experiments and clinical trials, MSC therapy is still largely restricted to the experimental stage due to its critical pitfalls and drawbacks such as safety issues, poor cell survival, immune rejection and high cost. On the other hand, MSC-derived EVs, which ideally reflect the exact biophysical features of MSCs, are considered to be much safer and more effective than MSCs themselves. Therefore, introducing alternative approaches based on MSC-derived EVs can offer appreciable promise in overcoming the limitations and practical challenges observed in cell-based therapy and thus the extracellular vesicles of MSCs may also provide a far more potent therapeutic strategy for immune-related disorders. In this review, we first focus on the properties of MSC-derived EVs and then we shall provide valuable insight regarding their beneficial therapeutic opportunities to further compare this alternative approach with conventional MSC therapy. Finally, we will attempt to summarize the current findings on the influences of MSC-derived EVs on autoimmune disorders, offering a potential alternative avenue towards treatment of autoimmune diseases.

Stem cell therapy in COVID-19: Pooled evidence from SARS-CoV-2, SARS-CoV, MERS-CoV and ARDS: A systematic review

BACKGROUND

SARS-CoV-2, which majorly affects the lungs and respiratory tract is thought due to dysregulation of the immune system which causes an immense imbalance of the cytokines. However, till now no standard treatment has been developed in treating the disease. On the other hand, it becomes important to prevent the acute respiratory tract infection due to COVID-19 which is the most dangerous phase leading to increased mortality. Hence this systematic review has been framed by pooling the available data of the use of stem cells in SARS-CoV-2, SARS-CoV, MERS-CoV and ARDS.

METHODS

6 literature databases (PubMed, EMBASE, Scopus, Google Scholar, Clinicaltrials.gov, and Clinical trial registry of India) were searched for relevant studies till 10th August 2020 using keywords stem cells, mesenchymal stem cells, cell therapy, SARS CoV-2, SARS Coronavirus, Coronavirus 2, COVID-19, nCoV-19, Novel Coronavirus, MERS CoV, ARDS, acute respiratory distress syndrome.

RESULTS

The observations of this systematic review suggest capability of MSCs in reducing the systemic inflammation and protecting against SARS-CoV-2 as evidenced by the available clinical data.

CONCLUSION

MSCs can overcome the clinical challenges currently faced by SARS-CoV-2 infected patients, specifically who are seriously ill and not responding to conventional therapies. Though the available clinical data is motivating, still predicting the therapeutic potential of MSCs will be too early in COVID-19. Hence, further studies in a larger cohort of patients becomes a prerequisite to validate their potential efficacy.

Current Trends in the Treatment of Systemic Lupus Erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is an autoimmune disease in mankind. SLE's downregulation of T and B lymphocytes could cause the development of autoantibodies, which in turn attack cell surface, nuclear, and cytoplasmic molecules, creating immune complexes that harm tissues.

OBJECTIVE

The objective of the present review is to evaluate SLE's present therapeutic policies and raise consciousness about the disease.

METHODS

New therapies are rare for SLE. This is due to the complexity of the disease and its various manifestations. Three techniques are used to develop biological treatments for the illness: B-cell modulation, T-cell regulation and cytokine inhibition. This paper reviews the present trends in SLE therapy.

RESULTS

Each arm of the immune system is a prospective therapeutic development target for this disease; it involves B-cells, T-cells, interferon (IFN) and cytokines. To date, only one of these agents is been approved for use against lupus, belimumab which comes under B-cell therapy. Both the innate and the adaptive immune systems are the objectives. Currently, although there is no full SLE remedy, drug therapy can minimize organ injury and control active disease, which relies on immunosuppressants and glucocorticoids.

CONCLUSION

It is possible to access SLE treatment in the form of T-cell, B-cell and anticytokine therapies. In these therapies, antibodies and antigens interactions play a major part. Another medication for treating SLE is the non-steroidal anti-inflammatory drug such as hydroxychloroquine. Glucocorticoids (GCs) are another antiinflammatory treatment that suppresses the growth of cytokines related to inflammation and prevents the recruitment of leukocyte by reducing endothelial cell permeability.

Extracellular microvesicles that originated adipose tissue derived mesenchymal stem cells have the potential ability to improve rheumatoid arthritis on mice

Introduction

Mesenchymal stem cells (MSCs) are promising therapeutic tools in regenerative medicine. In particularly adipose tissue derived MSC (AMSC) has powerful potential for the therapeutics of rheumatoid arthritis (RA) because these cells can control immune balance. RA systemically occurs autoimmune disease. Interestingly, IL-1 receptor antagonist deficient (IL-1ra^-/-) mice induce inflammation in joints like RA. In RA therapy, although AMSC improves the inflammation activity, it is little known to play roles of extracellular microvesicles (EV) for improvement of RA. To clarify the MSC-derived EVs are involved amelioration mechanisms for RA by themselves, we examined the functional effects of development for RA by AMSC-EVs.

Methods

We isolated AMSCs derived mice adipose tissue and purified EVs from the culture supernatant of AMSCs. To examine whether EVs can improve RA, we administrated EVs or AMSCs to IL-1ra knockout mice as RA model mice. We analyzed EVs-included factor by western blot methods and RA improvement effect by ELISA.

Results

In this study, we showed that the swellings of joints on mice in wild type AMSC and that in AMSC-EVs decreased than that in IL-1ra^-/- mice-AMSC-EVs and in none-treated. We detected IL-1ra expression in AMSC-EVs in wild type mice but not that in IL-1ra^-/- mice. Proinflammatory cytokine expression changes in mice showed in AMSCs and AMSC-EVs, but no apparent differences cytokine expressions were detected in IL-1ra^-/- mice.

Conclusions

In this study, we concluded that MSCs might improve RA by the transferring of factors such as IL-1ra, which are included their MSC derived- EVs.

The development of mesenchymal stem cell therapy in the present, and the perspective of cell-free therapy in the future

Cirrhosis is a chronic condition that can lead to liver failure. Currently, the viable option for decreasing mortality is liver transplantation. However, transplant surgery is highly invasive. Therefore, cell-based therapy has been developed as an alternative. Based on promising findings from preclinical research, some new trials have been registered. One of them was autologous bone marrow cell infusion therapy and found that ameliorating liver fibrosis activated liver regeneration. Now, majority of trials focus on low-immunogenicity mesenchymal stem cells (MSCs) appropriate for allogeneic administration. However, despite about 20 years of research, only a limited number of cell-based therapies have entered routine practice. Furthermore, potential shortcomings of cell-based therapy include a limit on the number of cells, which may be administered, as well as their failure to infiltrate target organs. On the other hand, these research show that MSCs act as "conducting cells" and regulate host cells including macrophages via extracellular vesicles (EVs) or exosome signals, leading to ameliorate liver fibrosis and promote regeneration. Therefore, the concept of cell-free therapy, which makes use of cell-derived EVs or exosomes, is attracting attention. Cell-free therapies may be safely administered in large doses and are able to infiltrate target organs. However, development of cell-free therapy exhibits its own set of challenges and such therapy may not be completely curative in the context of liver disease. This review describes the history of cell-based therapy research and recent advances in cell-free therapy, as well as discussing the need for more effective therapies.

Therapeutic Potential of Mesenchymal Stem Cells and Their Secretome in the Treatment of SARS-CoV-2-Induced Acute Respiratory Distress Syndrome

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent responsible for the development of a new coronavirus disease (COVID-19), is a highly transmittable virus which, in just ten months, infected more than 40 million people in 214 countries worldwide. After inhalation, aerosols containing SARS-CoV-2 penetrate to the depths of the lungs and cause severe pneumonia, alveolar injury, and life-threatening acute respiratory distress syndrome (ARDS). Since there are no specific drugs or vaccines available to cure or prevent COVID-19 infection and COVID-19-related ARDS, a new therapeutic agent which will support oxygen supply and, at the same time, efficiently alleviate SARS-CoV-2-induced lung inflammation is urgently needed. Due to their potent immuno- and angiomodulatory characteristics, mesenchymal stem cells (MSCs) may increase oxygen supply in the lungs and may efficiently alleviate ongoing lung inflammation, including SARS-CoV-2-induced ARDS. In this review article, we described molecular mechanisms that are responsible for MSC-based modulation of immune cells which play a pathogenic role in the development of SARS-CoV-2-induced ARDS and we provided a brief outline of already conducted and ongoing clinical studies that increase our understanding about the therapeutic potential of MSCs and their secretome in the therapy of COVID-19-related ARDS.

Adipose-derived stromal cells modulating composite allotransplant survival is correlated with B cell regulation in a rodent hind-limb allotransplantation model

Background

Our previous studies demonstrated that adipose-derived mesenchymal stromal cells (ASCs) have immunomodulatory effects that prolong allograft survival in a rodent hind-limb allotransplant model. In this study, we investigated whether the effects of immunomodulation by ASCs on allograft survival are correlated with B cell regulation.

Methods

B cells isolated from splenocytes were cocultured with ASCs harvested from adipose tissue from rodent groin areas for in vitro experiments. In an in vivo study, hind-limb allotransplantation from Brown-Norway to Lewis rats was performed, and rats were treated with ASCs combined with short-term treatment with anti-lymphocyte serum (ALS)/cyclosporine (CsA) as immunosuppressants. Peripheral blood and transplanted tissue were collected for further analysis.

Result

An in vitro study revealed that ASCs significantly suppressed lipopolysaccharide-activated B cell proliferation and increased the percentage of Bregs. The levels of immunoregulatory cytokines, such as TGF-β1 and IL-10, were significantly increased in supernatants of stimulated B cells cocultured with ASCs. The in vivo study showed that treatment with ASCs combined with short-term ALS/CsA significantly reduced the B cell population in alloskin tissue, increased the proportion of circulating CD45Ra⁺/Foxp3⁺ B cells, and decreased C4d expression in alloskin.

Conclusion

ASCs combined with short-term immunosuppressant treatment prolong allograft survival and are correlated with B cell regulation, C4d expression and the modulation of immunoregulatory cytokines.

MSC spheroids-loaded collagen hydrogels simultaneously promote neuronal differentiation and suppress inflammatory reaction through PI3K-Akt signaling pathway

It is critical for the clinical success to take the anti-inflammatory function into consideration when integrating the neurogenesis into the nerve repair materials. To this aim, we prepared mesenchymal stem cell (MSC) spheroids-loaded collagen (Col) hydrogels with combined superior anti-inflammatory efficacy and neurogenic activity. The size of the MSC spheroids showed a strong modulation effect on both functions, and the MSC spheroids-100 sample exhibited the best neuronal and anti-inflammatory potentials. The observed dual functions were likely based on the elevated intrinsic cell-cell contacts and cell-extracellular matrix interactions from the MSC spheroids. MSC self-assembly as spheroids expedited the secretions of endogenous trophic factors and extracellular matrix (ECM), which was beneficial to drive neural stem cell differentiation into the neuronal lineage. In addition, the formation of the MSC spheroids secreted more amounts and types of cytokines as well as immunomodulatory paracrine factors to suppress LPS-induced inflammatory reaction. LC-MS/MS analysis further demonstrated that MSC spheroids contributed to the activation of neuroactive ligand-receptor interaction, thereby triggering downstream PI3K-Akt signal pathway, which was likely due to the acceleration of ECM-receptor interaction, gap junction and tight junction. Importantly, inhibiting Akt pathway significantly suppressed the neuronal differentiation, indicating that PI3K-Akt signal pathway was critically involved in the Col-MSC spheroid hydrogel mediated neuroprotection and neurogenesis. Such findings not only provided a simple approach for improving MSC-based therapies for neuron-related diseases, but also shed insight on understanding the underlying mechanisms of MSC-mediated neuronal differentiation.

The Effects of Mesenchymal Stem Cells on Antimelanoma Immunity Depend on the Timing of Their Administration

There is still a lively debate about whether mesenchymal stem cells (MSCs) promote or suppress antitumor immune response. Although several possible explanations have been proposed, including different numbers of injected and engrafted MSCs, heterogeneity in phenotype, and function of tumor cells, the exact molecular mechanisms responsible for opposite effects of MSCs in modulation of antitumor immunity are still unknown. Herewith, we used a B16F10 murine melanoma model to investigate whether timing of MSC administration in tumor-bearing mice was crucially important for their effects on antitumor immunity. MSCs, intravenously injected 24 h after melanoma induction (B16F10+MSC^1d-treated mice), significantly enhanced natural killer (NK) and T cell-driven antitumor immunity, suppressed tumor growth, and improved survival of melanoma-bearing animals. Significantly higher plasma levels of antitumorigenic cytokines (TNF-α and IFN-γ), remarkably lower plasma levels of immunosuppressive cytokines (TGF-β and IL-10), and a significantly higher number of tumor-infiltrating, IFN-γ-producing, FasL- and granzyme B-expressing NK cells, IL-17-producing CD4+Th17 cells, IFN-γ- and TNF-α-producing CD4+Th1 cells, and CD8+cytotoxic T lymphocytes (CTLs) were observed in B16F10+MSC^1d-treated mice. On the contrary, MSCs, injected 14 days after melanoma induction (B16F10+MSC^14d-treated mice), promoted tumor growth by suppressing antigen-presenting properties of tumor-infiltrating dendritic cells (DCs) and macrophages and by reducing tumoricidal capacity of NK cells and T lymphocytes. Significantly higher plasma levels of TGF-β and IL-10, remarkably lower plasma levels of TNF-α and IFN-γ, and significantly reduced number of tumor-infiltrating, I-A-expressing, and IL-12-producing macrophages, CD80- and I-A-expressing DCs, granzyme B-expressing CTLs and NK cells, IFN-γ- and IL-17-producing CTLs, CD4+Th1, and Th17 cells were observed in B16F10+MSC^14d-treated animals. In summing up, the timing of MSC administration into the tumor microenvironment was crucially important for MSC-dependent modulation of antimelanoma immunity. MSCs transplanted during the initial phase of melanoma growth exerted tumor-suppressive effect, while MSCs injected during the progressive stage of melanoma development suppressed antitumor immunity and enhanced tumor expansion.

Mesenchymal Stem Cell-Based Therapy for Allergic Rhinitis

Allergic rhinitis (AR) is a prevalent disorder that causes a significant and often underestimated health burden for individuals and society. The current drug treatment cannot essentially deal with the regulation of the allergic reaction, while the allergic symptoms could be alleviated. Mesenchymal stem cells (MSCs) bear a variety of properties, such as the ability to differentiate into various cell lineages, to secrete soluble factors crucial for cell survival and proliferation, to migrate to the exact site of injury, and to modulate the immune response. Clinical studies have been extensively conducted in MSCs as the models for varieties of diseases such as neurological diseases. Due to their immunomodulatory properties, the MSCs have gradually been believed to become one of the promising strategies for AR treatments although so far the MSCs-mediated treatment for AR is still at animal experiments stage. Fully understanding the roles and mechanisms of MSCs immunomodulatory effects serves as the prerequisite that will be beneficial to the application of MSCs-based AR clinical treatment methods. In this review article, we highlighted the recent research advances and give a brief perspective in the future study of the MSCs-mediated therapeutic application in AR treatments.

Immunopathology in schistosomiasis is regulated by TLR2,4- and IFN-γ-activated MSC through modulating Th1/Th2 responses

Background and aims

A marked egg-induced CD4⁺ T cell programmed inflammation and subsequent hepatic fibrosis characterize the pathogenesis of schistosomiasis. Mesenchymal stem cell (MSC) has been extensively studied for the treatment of schistosomiasis. However, the mechanism by which MSCs modulate the pathogenesis of schistosomiasis has not been clarified. Furthermore, the local inflammatory milieu may greatly influence the immunoregulatory properties of MSCs, and our early experiments demonstrated that Toll-like receptor (TLR)2/TLR4 agonist effected immune modulation of MSC. Here, we further investigated their modulation on the pathogenesis of schistosomiasis.

Methods

Adult BALB/c male mice were percutaneously infected with 16 ± 2 pairs S. japonicum cercariae and received intravenously pretreated MSC at 1 week and 3 weeks post-infection, respectively. At 8 weeks post-infection, effects of MSC on liver histology were shown by hematoxylin and eosin (H&E) staining and Masson staining and quantitatively compared by the hepatic hydroxyproline content; α-smooth muscle actin (α-SMA), collagen type I(Col-1), transforming growth factor β (TGF-β), and tumor necrosis factor-α (TNF-α) gene expression in the liver were assessed by semi-quantitative polymerase chain reaction (PCR); the Th1/Th2 dominance among different groups was compared by analyzing CD4⁺ interferon-γ (IFN-γ)+ and CD4+interleukin-4 (IL-4)+T cells in the liver by flow cytometry and serum level of IFN-γ and IL-5 using enzyme-linked immunosorbent assay (ELISA). Effects of different kinds of MSC were further evaluated in vitro by the coculture system.

Results

Results showed TLR4- and IFN-γ-activated MSC alleviated liver fibrosis in infected mice, without a significant increase of mortality, and unpretreated MSC showed no clear improvement; however, TLR2- and IFN-γ-activated MSC displayed aggravated immunopathology. In accord with the pathological results, TLR4- and IFN-γ-activated MSC groups showed moderate enhancement of Th1 response in vitro and clear Th1 dominance in vivo without leading to extreme inflammation, whereas TLR2- and IFN-γ-activated MSC not only induced Th1 response, but also triggered excessive inflammation as evidenced by atrophy of the thymus and higher TNF level in the coculture system.

Conclusions

This study demonstrates that TLR4 combined with IFN-γ can activate the MSC group with positive effects on the pathology of schistosomiasis by modulating Th subsets at some degree. This result suggests that when MSC is being used to treat different immuno-disturbance complications, subtle pretreatment methods should be seriously considered.

Therapeutic Use of Mesenchymal Stem Cell-Derived Exosomes: From Basic Science to Clinics

Mesenchymal stem cells (MSC) are, due to their immunosuppressive and regenerative properties, used as new therapeutic agents in cell-based therapy of inflammatory and degenerative diseases. A large number of experimental and clinical studies revealed that most of MSC-mediated beneficial effects were attributed to the effects of MSC-sourced exosomes (MSC-Exos). MSC-Exos are nano-sized extracellular vesicles that contain MSC-derived bioactive molecules (messenger RNA (mRNA), microRNAs (miRNAs)), enzymes, cytokines, chemokines, and growth factors) that modulate phenotype, function and homing of immune cells, and regulate survival and proliferation of parenchymal cells. In this review article, we emphasized current knowledge about molecular and cellular mechanisms that were responsible for MSC-Exos-based beneficial effects in experimental models and clinical trials. Additionally, we elaborated on the challenges of conventional MSC-Exos administration and proposed the use of new bioengineering and cellular modification techniques which could enhance therapeutic effects of MSC-Exos in alleviation of inflammatory and degenerative diseases.

Ability of human umbilical cord mesenchymal stem cells to repair chemotherapy-induced premature ovarian failure

BACKGROUND

Premature ovarian insufficiency (POI) and premature ovarian failure (POF) have become one of the major problems threatening women of childbearing age. Studies have shown that stem cells transplanted from bone marrow, umbilical cord, peripheral blood and amniotic fluid can migrate and proliferate to the ovary, promote ovarian function repair, increase the number of follicles and granulosa cells at all levels of ovary, improve endocrine function, and can differentiate into oocytes in specific ovarian environment to restore fertility to some extent.

AIM

To study the ability of human umbilical cord mesenchymal stem cells (hUCMSCs) to repair ovarian injury after chemotherapy.

METHODS

A total of 110 female BALB/c mice (aged 7-8 wk old) with body masses of 16.0-20.0 g were selected. The mice were fed until 12 wk of age, and cyclophosphamide was administered by intraperitoneal injection for 14 consecutive days to induce premature ovarian failure in mice. Seventy-five mice with estrous cycle disorder were screened and randomly divided into 3 groups according to their body weight: model group, positive control group and hUCMSC group, and each group had 25 mice. Another 25 mice were used as negative controls. The mice in the hUCMSC group were injected with hUCMSCs in the tail vein, and the mice in the positive control group were given an oestradiol valerate solution and a medroxyprogesterone acetate solution in the tail vein. On the 1^st, 15^th, 30^th, 45^th, and 60^th days after intravenous administration, vaginal smears were made to monitor the estrous cycles of the mice. The ovaries were weighed, and pathological sections were made to observe the morphology of the follicles; blood samples were collected to monitor the concentration of sex hormones (oestradiol and follicle-stimulating hormone).

RESULTS

The estrous cycles of the model group mice were disrupted throughout the experiment. Mice in the hUCMSC group and the positive control group resumed normal estrous cycles. The ovarian weight of the model group mice continued to decline. The ovarian weight of the hUCMSC group mice and the positive control group mice decreased first and then gradually increased, and the ovarian weight of the hUCMSC group mice was heavier than that of the positive control group mice. The difference was statistically significant (P < 0.05). Compared with the negative control group, the model group experienced a decrease in oestradiol and an increase in follicle-stimulating hormone, and the difference was statistically significant (P < 0.05). Compared with the model group, the hUCMSC and positive control groups experienced a slight increase in oestradiol and a decrease in follicle-stimulating hormone; the difference was statistically significant (P < 0.05). The pathological examination revealed that the mouse ovaries from the model group were atrophied, the volume was reduced, the cortical and medullary structures were disordered, the number of follicles at all stages was significantly reduced, the number of atretic follicles increased, the number of primordial follicles and corpus luteum significantly decreased, and the corpus luteum had an irregular shape. Compared with those of the model group, the lesions of the hUCMSC and positive control groups significantly improved.

CONCLUSION

hUCMSCs can repair ovarian tissue damaged by chemotherapy to a certain extent, can improve the degree of apoptosis in ovarian tissue, and can improve the endocrine function of mouse ovaries.

Mesenchymal stem cells alleviate rat diabetic nephropathy by suppressing CD103+ DCs-mediated CD8+ T cell responses

Diabetic nephropathy (DN) as a kind of serious microvascular complication of Diabetes Mellitus (DM) usually causes the end‐stage of renal disease (ESRD). Studies have demonstrated that CD103⁺ dendritic cells (DCs) exhibited a renal pathogenic effect in murine chronic kidney disease (CKD). Mesenchymal stem cells (MSCs) can alleviate DN and suppress the DCs maturation. To explore the role of CD103⁺ DCs and the potential mechanisms underlying MSCs‐mediated protective effects in DN, we used bone marrow MSCs (BM‐MSCs) to treat DN rats. MSCs transplantation considerably recovered kidney function and diminished renal injury, fibrosis and the population of renal CD103⁺ DCs in DN rat. The MSCs‐treated DN rats had decreased mRNA expression levels of interleukin (IL)1β, IL6, tumour necrosis factor alpha (TNF‐α), monocyte chemotactic protein 1 (MCP‐1) and reduced CD8 T cell infiltration in the kidney. MSCs significantly down‐regulated the genes expression of transcription factors (Basic leucine zipper transcriptional factor ATF‐like 3, Batf3 and DNA‐binding protein inhibitor ID‐2, Id2) and FMS‐like tyrosine kinase‐3 (Flt3) which are necessary for CD103⁺ DCs development. The protective effect of MSCs may be partly related to their immunosuppression of CD8⁺ T cell proliferation and activation mediated by CD103⁺ DCs in the kidney of DN rats.

Neocortical tissue recovery in severe congenital obstructive hydrocephalus after intraventricular administration of bone marrow-derived mesenchymal stem cells

Background

In obstructive congenital hydrocephalus, cerebrospinal fluid accumulation is associated with high intracranial pressure and the presence of periventricular edema, ischemia/hypoxia, damage of the white matter, and glial reactions in the neocortex. The viability and short time effects of a therapy based on bone marrow-derived mesenchymal stem cells (BM-MSC) have been evaluated in such pathological conditions in the hyh mouse model.

Methods

BM-MSC obtained from mice expressing fluorescent mRFP1 protein were injected into the lateral ventricle of hydrocephalic hyh mice at the moment they present a very severe form of the disease. The effect of transplantation in the neocortex was compared with hydrocephalic hyh mice injected with the vehicle and non-hydrocephalic littermates. Neural cell populations and the possibility of transdifferentiation were analyzed. The possibility of a tissue recovering was investigated using ¹H High-Resolution Magic Angle Spinning Nuclear Magnetic Resonance (¹H HR-MAS NMR) spectroscopy, thus allowing the detection of metabolites/osmolytes related with hydrocephalus severity and outcome in the neocortex. An in vitro assay to simulate the periventricular astrocyte reaction conditions was performed using BM-MSC under high TNFα level condition. The secretome in the culture medium was analyzed in this assay.

Results

Four days after transplantation, BM-MSC were found undifferentiated and scattered into the astrocyte reaction present in the damaged neocortex white matter. Tissue rejection to the integrated BM-MSC was not detected 4 days after transplantation. Hyh mice transplanted with BM-MSC showed a reduction in the apoptosis in the periventricular neocortex walls, suggesting a neuroprotector effect of the BM-MSC in these conditions. A decrease in the levels of metabolites/osmolytes in the neocortex, such as taurine and neuroexcytotoxic glutamate, also indicated a tissue recovering. Under high TNFα level condition in vitro, BM-MSC showed an upregulation of cytokine and protein secretion that may explain homing, immunomodulation, and vascular permeability, and therefore the tissue recovering.

Conclusions

BM-MSC treatment in severe congenital hydrocephalus is viable and leads to the recovery of the severe neurodegenerative conditions in the neocortex. NMR spectroscopy allows to follow-up the effects of stem cell therapy in hydrocephalus.

The role of Interleukin 1 receptor antagonist in mesenchymal stem cell-based tissue repair and regeneration

Interleukin (IL)-1 receptor antagonist (IL-1Ra), a naturally occurring antagonist of IL-1α/IL-1β signaling pathways, has been attributed to the immunosuppressive effects of mesenchymal stem cells (MSCs). MSCs, in IL-1Ra-dependent manner, suppressed production of IL-1β in dermal macrophages, induced their polarization in anti-inflammatory M2 phenotype, attenuated antigen-presenting properties of dendritic cells (DCs), and promoted expansion of immunosuppressive T regulatory cells in the skin, which resulted in enhanced repair of the nonhealing wounds. Reduced activation of inflammasome and suppressed production of IL-1β in macrophages were mainly responsible for beneficial effects of MSC-derived IL-1Ra in alleviation of acute lung injury, dry eye syndrome, and corneal injury. Through the production of IL-1Ra, MSCs reduced migration of DCs to the draining lymph nodes and attenuated generation of inflammatory Th1 and Th17 cells that resulted in alleviation of fulminant hepatitis and rheumatoid arthritis. MSCs, in IL-1Ra-dependent manner, reduced liver fibrosis by suppressing production of Type I collagen in hepatic stellate cells. IL-1Ra was, at least partially, responsible for enhanced proliferation of hepatocytes and chondrocytes in MSC-treated animals with partial hepatectomy and osteoarthritis. Despite of these beneficial effects, IL-1Ra-dependent inhibition of IL-1α/IL-1β-signaling significantly increased risk of infections. Therefore, future experimental and clinical studies should delineate potential side effects of MSC-derived IL-1Ra before IL-1Ra-overexpressing MSCs could be used as a potentially new therapeutic agent for the treatment of acute and chronic inflammatory diseases.

Genetically Modified Mouse Mesenchymal Stem Cells Expressing Non-Structural Proteins of Hepatitis C Virus Induce Effective Immune Response

Hepatitis C virus (HCV) is one of the major causes of chronic liver disease and leads to cirrhosis and hepatocarcinoma. Despite extensive research, there is still no vaccine against HCV. In order to induce an immune response in DBA/2J mice against HCV, we obtained modified mouse mesenchymal stem cells (mMSCs) simultaneously expressing five nonstructural HCV proteins (NS3-NS5B). The innate immune response to mMSCs was higher than to DNA immunization, with plasmid encoding the same proteins, and to naïve unmodified MSCs. mMSCs triggered strong phagocytic activity, enhanced lymphocyte proliferation, and production of type I and II interferons. The adaptive immune response to mMSCs was also more pronounced than in the case of DNA immunization, as exemplified by a fourfold stronger stimulation of lymphocyte proliferation in response to HCV, a 2.6-fold higher rate of biosynthesis, and a 30-fold higher rate of secretion of IFN-γ, as well as by a 40-fold stronger production of IgG2a antibodies to viral proteins. The immunostimulatory effect of mMSCs was associated with pronounced IL-6 secretion and reduction in the population of myeloid derived suppressor cells (MDSCs). Thus, this is the first example that suggests the feasibility of using mMSCs for the development of an effective anti-HCV vaccine.

Soluble PTX3 of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells Attenuates Hyperoxic Lung Injury by Activating Macrophage Polarization in Neonatal Rat Model

Therapeutic treatment of various inflammation-related diseases using mesenchymal stem cells (MSCs) has increased in recent years because of the paracrine action of these cells but shows several limitations. First, MSC-based therapies exhibit varying efficacies; thus, biomarkers should be determined to identify who may benefit from these candidate therapeutic agents. Second, the mechanism underlying the therapeutic effects is poorly understood. To evaluate the effects of human umbilical cord blood-derived MSCs (UCB-MSCs) on macrophages, the macrophage cell line NR8383 stimulated with lipopolysaccharide (LPS) was cocultured by UCB-MSCs. We found that UCB-MSCs mediated changes in macrophage polarization towards M2 from M1 macrophages. To identify the paracrine action underlying the anti-inflammation effect of UCB-MSCs, the secretion of UCB-MSCs exposed to LPS-stimulated NR8383 cells was tested using a biotin label-based 507 antibody array. Among the secreted proteins, we selected pentraxin-related protein PTX3/tumor necrosis factor-inducible gene 14 protein (PTX3) to investigate its association with UCB-MSCs in macrophage polarization. We found that human PTX3 was secreted from UCB-MSCs under inflammation condition and reinforced the M2 macrophage marker via the Dectin-1 receptor by activating MSK1/2 phosphorylation signaling in NR8383 cells. Accordingly, knockdown of PTX3 in UCB-MSCs significantly attenuated their therapeutic effects in a neonatal hyperoxic lung injury resulting in reduced survival, lung alveolarization, M2 marker expression, Dectin-1 levels, anti-inflammatory cytokines, and improved M1 marker expression and inflammatory cytokines compared to control MSC-injected rats. UCB-MSCs show therapeutic potential by controlling macrophage polarization. Interestingly, higher PTX3 levels in UCB-MSCs induced greater improvement in the therapeutic effects than lower PTX3 levels. Collectively, PTX3 is a potential marker with critical paracrine effects for predicting the therapeutic potential of MSC therapy in inflammatory diseases; quality control assessments using PTX3 may be useful for improving the therapeutic effects of UCB-MSCs.

Therapeutic Potential of Mesenchymal Stem Cells and Their Secretome in the Treatment of Glaucoma

Glaucoma represents a group of progressive optic neuropathies characterized by gradual loss of retinal ganglion cells (RGCs), the neurons that conduct visual information from the retina to the brain. Elevated intraocular pressure (IOP) is considered the main reason for enhanced apoptosis of RGCs in glaucoma. Currently used therapeutic agents are not able to repopulate and/or regenerate injured RGCs and, therefore, are ineffective in most patients with advanced glaucoma. Accordingly, several new therapeutic approaches, including stem cell-based therapy, have been explored for the glaucoma treatment. In this review article, we emphasized current knowledge regarding molecular and cellular mechanisms responsible for beneficial effects of mesenchymal stem cells (MSCs) and their secretome in the treatment of glaucoma. MSCs produce neurotrophins and in an exosome-dependent manner supply injured RGCs with growth factors enhancing their survival and regeneration. Additionally, MSCs are able to generate functional RGC-like cells and induce proliferation of retinal stem cells. By supporting integrity of trabecular meshwork, transplanted MSCs alleviate IOP resulting in reduced loss of RGCs. Moreover, MSCs are able to attenuate T cell-driven retinal inflammation providing protection to the injured retinal tissue. In summing up, due to their capacity for neuroprotection and immunomodulation, MSCs and their secretome could be explored in upcoming clinical studies as new therapeutic agents for glaucoma treatment.

Mesenchymal Stem Cell-Derived Exosomes and Other Extracellular Vesicles as New Remedies in the Therapy of Inflammatory Diseases

There is growing evidence that mesenchymal stem cell (MSC)-based immunosuppression was mainly attributed to the effects of MSC-derived extracellular vesicles (MSC-EVs). MSC-EVs are enriched with MSC-sourced bioactive molecules (messenger RNA (mRNA), microRNAs (miRNAs), cytokines, chemokines, immunomodulatory factors) that regulate phenotype, function and homing of immune cells. In this review article we emphasized current knowledge regarding molecular mechanisms responsible for the therapeutic effects of MSC-EVs in attenuation of autoimmune and inflammatory diseases. We described the disease-specific cellular targets of MSC-EVs and defined MSC-sourced molecules, which were responsible for MSC-EV-based immunosuppression. Results obtained in a large number of experimental studies revealed that both local and systemic administration of MSC-EVs efficiently suppressed detrimental immune response in inflamed tissues and promoted survival and regeneration of injured parenchymal cells. MSC-EVs-based anti-inflammatory effects were relied on the delivery of immunoregulatory miRNAs and immunomodulatory proteins in inflammatory immune cells (M1 macrophages, dendritic cells (DCs), CD4+Th1 and Th17 cells), enabling their phenotypic conversion into immunosuppressive M2 macrophages, tolerogenic DCs and T regulatory cells. Additionally, through the delivery of mRNAs and miRNAs, MSC-EVs activated autophagy and/or inhibited apoptosis, necrosis and oxidative stress in injured hepatocytes, neurons, retinal cells, lung, gut and renal epithelial cells, promoting their survival and regeneration.

Therapeutic Potential of Amniotic Fluid Derived Mesenchymal Stem Cells Based on their Differentiation Capacity and Immunomodulatory Properties

BACKGROUND

Amniotic Fluid Derived Mesenchymal Stem Cells (AF-MSCs) are adult, fibroblast- like, self-renewable, multipotent stem cells. During the last decade, the therapeutic potential of AF-MSCs, based on their huge differentiation capacity and immunomodulatory characteristics, has been extensively explored in animal models of degenerative and inflammatory diseases.

OBJECTIVE

In order to describe molecular mechanisms responsible for the therapeutic effects of AFMSCs, we summarized current knowledge about phenotype, differentiation potential and immunosuppressive properties of AF-MSCs.

METHODS

An extensive literature review was carried out in March 2018 across several databases (MEDLINE, EMBASE, Google Scholar), from 1990 to present. Keywords used in the selection were: "amniotic fluid derived mesenchymal stem cells", "cell-therapy", "degenerative diseases", "inflammatory diseases", "regeneration", "immunosuppression". Studies that emphasized molecular and cellular mechanisms responsible for AF-MSC-based therapy were analyzed in this review.

RESULTS

AF-MSCs have huge differentiation and immunosuppressive potential. AF-MSCs are capable of generating cells of mesodermal origin (chondrocytes, osteocytes and adipocytes), neural cells, hepatocytes, alveolar epithelial cells, insulin-producing cells, cardiomyocytes and germ cells. AF-MSCs, in juxtacrine or paracrine manner, regulate proliferation, activation and effector function of immune cells. Due to their huge differentiation capacity and immunosuppressive characteristic, transplantation of AFMSCs showed beneficent effects in animal models of degenerative and inflammatory diseases of nervous, respiratory, urogenital, cardiovascular and gastrointestinal system.

CONCLUSION

Considering the fact that amniotic fluid is obtained through routine prenatal diagnosis, with minimal invasive procedure and without ethical concerns, AF-MSCs represents a valuable source for cell-based therapy of organ-specific or systemic degenerative and inflammatory diseases.

Therapeutic Potential of “Exosomes Derived Multiple Allogeneic Proteins Paracrine Signaling: Exosomes d-MAPPS” is Based on the Effects of Exosomes, Immunosuppressive and Trophic Factors

Due to their differentiation capacity and potent immunosuppressive and pro-angiogenic properties, mesenchymal stem cells (MSCs) have been considered as new therapeutic agents in regenerative medicine. Since most of MSC-mediated beneficent effects are a consequence of their paracrine action, we designed MSC-based product “Exosomes Derived Multiple Allogeneic Proteins Paracrine Signaling (Exosomes d-MAPPS), which activity is based on MSCs-derived growth factors and immunomodulatory cytokines capable to attenuate inflammation and to promote regeneration of injured tissues. Interleukin 1 receptor antagonist (IL-1Ra) and IL-27 were found in high concentrations in Exosomes d-MAPPS samples indicating strong anti-inflammatory and immunosuppressive potential of Exosomes d-MAPPS. Additionally, high concentrations of vascular endothelial growth factor receptor (VEGFR1) and chemokines (CXCL16, CCL21, CXCL14) were noticed at Exosomes d-MAPPS samples suggesting their potential to promote generation of new blood vessels and migration of CXCR6, CCR7 and CXCR4 expressing cells. Since all proteins which were found in high concentration in Exosomes d-MAPPS samples (IL-1Ra, CXCL16, CXCL14, CCL21, IL-27 and VEGFR1) are involved in modulation of lung, eye, and synovial inflammation, Exosomes d-MAPPS samples were prepared as inhalation and ophthalmic solutions in addition to injection formulations; their application in several patients suffering from chronic obstructive pulmonary disease, osteoarthritis, and dry eye syndrome resulted with significant improvement of biochemical and functional parameters. In conclusion, Exosomes d-MAPPS, due to the presence of important anti-inflammatory, immunomodulatory, and pro-angiogenic factors, represents potentially new therapeutic agent in regenerative medicine that should be further tested in large clinical studies.

Equine Fetal, Adult, and Embryonic Stem Cell-Derived Tenocytes Are All Immune Privileged but Exhibit Different Immune Suppressive Properties In Vitro

In horses and humans, tendon injuries are a significant problem. Not only can they occur in both athletes and nonathletes, they require lengthy periods of recuperation and undergo poor natural regeneration, which leads to high reinjury rates. Embryonic stem cells (ESCs) may provide a renewable source of allogeneic cells to use in clinical applications to aid tissue regeneration. Equine ESCs can undergo tenocyte differentiation in vivo and in vitro, but the immune properties of tenocytes isolated from either ESCs or tissues have not previously been characterized. Here, we demonstrate that equine tenocytes derived from fetal and adult tendon tissue and ESCs express robust levels of major histocompatibility complex (MHC) I but no MHC II in response to inflammatory cytokine interferon gamma (IFNγ). However, MHC expression does not affect their allorecognition by peripheral blood mononuclear cells in vitro. Adult and fetal tenocytes remain immune privileged and strongly immune suppressive in both the presence and absence of exogenously applied IFNγ. In contrast, ESC-derived tenocytes are immune privileged even in the presence of IFNγ, but they are only weakly immune suppressive in the presence but not in the absence of exogenously applied IFNγ. This is despite ESC-tenocytes expressing a number of genes involved in immune modulation at significantly higher levels than those expressed by adult and fetal tenocytes when in standard, nonstimulated monolayer culture. Together, this work suggests that, similar to other fibroblasts, tenocytes have immune modulatory properties, and that culture-expanded tenocytes derived from primary tissues or ESCs may be safe to use in clinical transplantations to injured tendons of unrelated animals.

Mesenchymal stem cell therapies for liver cirrhosis: MSCs as "conducting cells" for improvement of liver fibrosis and regeneration

Mesenchymal stem cells (MSCs) can be cultured relatively easily and can be obtained not only from the bone marrow, but also from medical waste such as adipose tissue and umbilical cord tissue. Because of its low antigenicity, allogeneic MSC injection is safe. MSCs have been evaluated in more than 900 clinical trials in a variety of fields, with more than 50 clinical trials related to liver diseases. Experiments have suggested that MSCs function as "conducting cells" to affect various "effective cells" such as T cells, B cells, and macrophages. Recent clinical trials have focused on allogeneic MSCs. Thus, studies are needed to determine the most effective cell source, culture conditions, cell numbers, administration frequency, administration route, cost, safety, and liver disease treatments. Recently, the functions of exosomes have gained attention, and cell-free therapy may become possible as an alternative therapy for liver disease. In this review, we introduce general information, mechanism, representative clinical study data, recently started or planned clinical trials, and possibility of cell-free therapy of MSCs.

The Role of Mesenchymal Stem Cells in Atherosclerosis: Prospects for Therapy via the Modulation of Inflammatory Milieu

Atherosclerosis is a chronic, inflammatory disease that mainly affects the arterial intima. The disease is more prevalent in middle-age and older individuals with one or more cardiovascular risk factors, including dyslipidemia, hypertension, diabetes, smoking, obesity, and others. The beginning and development of atherosclerosis has been associated with several immune components, including infiltration of inflammatory cells, monocyte/macrophage-derived foam cells, and inflammatory cytokines and chemokines. Mesenchymal stem cells (MSCs) originate from several tissue sources of the body and have self-renewal and multipotent differentiation characteristics. They also have immunomodulatory and anti-inflammatory properties. Recently, it was shown that MSCs have a regulatory role in plasma lipid levels. In addition, MSCs have shown to have promising potential in terms of treatment strategies for several diseases, including those with an inflammatory component. In this regard, transplantation of MSCs to patients with atherosclerosis has been proposed as a novel strategy in the treatment of this disease. In this review, we summarize the current advancements regarding MSCs for the treatment of atherosclerosis.

Noninvasive application of mesenchymal stem cell spheres derived from hESC accelerates wound healing in a CXCL12-CXCR4 axis-dependent manner

Mesenchymal stem cells (MSC) derived from adult tissues effectively promote wound healing. However, MSC quality varies, and the quantity of MSC is limited, as MSC are acquired through donations. Moreover, the survival and functioning of dissociated MSC delivered to an inflammatory lesion are subject to challenges.

Methods: Here, spheres (EMSC_Sp) generated from human embryonic stem cell-derived MSC (EMSC) were directly dropped onto excised wounds in mice; the effects of EMSC_Sp were compared to those of dissociated EMSC (EMSC_Diss). Following transplantation, we measured the extent of wound closure, dissected the histological features of the wounds, determined transcriptomic changes in cells isolated from the treated and control wounds, and evaluated the molecular mechanism of the effects of EMSC.

Results: The application of EMSC_Sp onto murine dermal wounds substantially increased survival and efficacy of EMSC compared to the topical application of EMSC_Diss. RNA sequencing (RNA-Seq) of cells isolated from the wounds highlighted the involvement of CXCL12-CXCR4 signaling in the effects of EMSC_Sp, which was verified in EMSC via CXCL12 knockdown and in target cells (vascular endothelial cells, epithelial keratinocytes, and macrophages) via CXCR4 inhibition. Finally, we enhanced the biosafety of EMSC_Sp by engineering cells with an inducible suicide gene.

Conclusions: Together, these data suggest the topical application of EMSC_Sp as an unlimited, quality-assured, safe, and noninvasive therapy for wound healing and the CXCL12-CXCR4 axis as a key player in this treatment.

Therapeutic Potential of Mesenchymal Stem Cell-Derived Exosomes in the Treatment of Eye Diseases

Mesenchymal stem cells (MSCs) were, due to their immunomodulatory and pro-angiogenic characteristics, extensively explored as new therapeutic agents in cell-based therapy of uveitis, glaucoma, retinal and ocular surface diseases.Since it was recently revealed that exosomes play an important role in biological functions of MSCs, herewith we summarized current knowledge about the morphology, structure, phenotype and functional characteristics of MSC-derived exosomes emphasizing their therapeutic potential in the treatment of eye diseases.MSC-derived exosomes were as efficient as transplanted MSCs in limiting the extent of eye injury and inflammation. Immediately after intravitreal injection, MSC-derived exosomes, due to nano-dimension, diffused rapidly throughout the retina and significantly attenuated retinal damage and inflammation. MSC-derived exosomes successfully delivered trophic and immunomodulatory factors to the inner retina and efficiently promoted survival and neuritogenesis of injured retinal ganglion cells. MSC-derived exosomes efficiently suppressed migration of inflammatory cells, attenuated detrimental Th1 and Th17 cell-driven immune response and ameliorated experimental autoimmune uveitis. MSC-derived exosomes were able to fuse with the lysosomes within corneal cells, enabling delivering of MSC-derived active β-glucuronidase and consequent catabolism of accumulated glycosaminoglycans, indicating their therapeutic potential in the treatment of Mucopolysaccharidosis VII (Sly Syndrome). Importantly, beneficent effects were noticed only in animals that received MSC-derived exosomes and were not seen after therapy with fibroblasts-derived exosomes confirming specific therapeutic potential of MSCs and their products in the treatment of eye diseases.In conclusion, MSC-derived exosomes represent potentially new therapeutic agents in the therapy of degenerative and inflammatory ocular diseases.

Mesenchymal stem cells prevent the progression of diabetic nephropathy by improving mitochondrial function in tubular epithelial cells

The administration of mesenchymal stem cells (MSCs) was shown to attenuate overt as well as early diabetic nephropathy in rodents, but the underlying mechanism of this beneficial effect is largely unknown. Inflammation and mitochondrial dysfunction are major pathogenic factors in diabetic nephropathy. In this study, we found that the repeated administration of MSCs prevents albuminuria and injury to tubular epithelial cells (TECs), an important element in the progression of diabetic nephropathy, by improving mitochondrial function. The expression of M1 macrophage markers was significantly increased in diabetic kidneys compared with that in control kidneys. Interestingly, the expression of arginase-1 (Arg1), an important M2 macrophage marker, was reduced in diabetic kidneys and increased by MSC treatment. In cultured TECs, conditioned media from lipopolysaccharide-activated macrophages reduced peroxisomal proliferator-activated receptor gamma coactivator 1α (Pgc1a) expression and impaired mitochondrial function. The coculture of macrophages with MSCs increased and decreased the expression of Arg1 and M1 markers, respectively. Treatment with conditioned media from cocultured macrophages prevented activated macrophage-induced mitochondrial dysfunction in TECs. In the absence of MSC coculture, Arg1 overexpression in macrophages reversed Pgc1a suppression in TECs. These observations suggest that MSCs prevent the progression of diabetic nephropathy by reversing mitochondrial dysfunction in TECs via the induction of Arg1 in macrophages.

Stem cells can halt the progression of kidney damage owing to diabetes by reducing inflammation and improving energy production in kidney cells. Eun Hee Koh at the University of Ulsan College of Medicine in Seoul, South Korea, and colleagues found that adult stem cells, known as mesenchymal stem cells (MSCs), derived from human umbilical cord blood had a protective effect on the kidneys of diabetic mice. Repeated administration of MSCs prevented the recruitment of pro-inflammatory cells into the kidney and increased the levels of arginase-1, a marker of cells with anti-inflammatory activity. Experiments in cells showed that MSCs stimulated the production of arginase-1 in that, in turn, were able to increase the production and activity of mitochondria in kidney cells. This study confirms an important role for MSCs in organ repair.

Generation of mesenchymal stem-like cells for producing extracellular vesicles

Mesenchymal stem cells (MSCs) are multipotent progenitor cells with therapeutic potential against autoimmune diseases, inflammation, ischemia, and metabolic disorders. Contrary to the previous conceptions, recent studies have revealed that the tissue repair and immunomodulatory functions of MSCs are largely attributed to their secretome, rather than their potential to differentiate into desired cell types. The composition of MSC secretome encompasses cytokines and growth factors, in addition to the cell-derived structures known as extracellular vesicles (EVs). EVs are membrane-enclosed nanoparticles that are capable of delivering biomolecules, and it is now believed that MSC-derived EVs are the major players that induce biological changes in the target tissues. Based on these EVs’ characteristics, the potential of EVs derived from MSC (MSC-EV) in terms of tissue regeneration and immune modulation has grown during the last decade. However, the use of MSCs for producing sufficient amount of EVs has not been satisfactory due to limitations in the cell growth and large variations among the donor cell types. In this regard, pluripotent stem cells (PSCs)-derived MSC-like cells, which can be robustly induced and expanded in vitro, have emerged as more accessible cell source that can overcome current limitations of using MSCs for EV production. In this review, we have highlighted the methods of generating MSC-like cells from PSCs and their therapeutic outcome in preclinical studies. Finally, we have also discussed future requirements for making this cell-free therapy clinically feasible.

Molecular Mechanisms Responsible for Therapeutic Potential of Mesenchymal Stem Cell-Derived Secretome

Mesenchymal stem cell (MSC)-sourced secretome, defined as the set of MSC-derived bioactive factors (soluble proteins, nucleic acids, lipids and extracellular vesicles), showed therapeutic effects similar to those observed after transplantation of MSCs. MSC-derived secretome may bypass many side effects of MSC-based therapy, including unwanted differentiation of engrafted MSCs. In contrast to MSCs which had to be expanded in culture to reach optimal cell number for transplantation, MSC-sourced secretome is immediately available for treatment of acute conditions, including fulminant hepatitis, cerebral ischemia and myocardial infarction. Additionally, MSC-derived secretome could be massively produced from commercially available cell lines avoiding invasive cell collection procedure. In this review article we emphasized molecular and cellular mechanisms that were responsible for beneficial effects of MSC-derived secretomes in the treatment of degenerative and inflammatory diseases of hepatobiliary, respiratory, musculoskeletal, gastrointestinal, cardiovascular and nervous system. Results obtained in a large number of studies suggested that administration of MSC-derived secretomes represents a new, cell-free therapeutic approach for attenuation of inflammatory and degenerative diseases. Therapeutic effects of MSC-sourced secretomes relied on their capacity to deliver genetic material, growth and immunomodulatory factors to the target cells enabling activation of anti-apoptotic and pro-survival pathways that resulted in tissue repair and regeneration.

Role of mesenchymal stem cell-derived soluble factors and folic acid in wound healing

Background/aim

Mesenchymal stem cells (MSCs) are a type of adult stem cell consisting of a heterogeneous subset of stromal stem cells that can be isolated from adult tissues. Folic acid is another important contributor to tissue regeneration and repair, which affects the synthesis of some building block molecules used for wound healing. In this study, we examine the effect of folic acid and MSCderived soluble factors in the wound healing model.

Materials and methods

Human umbilical vein endothelial cells (HUVECs) and bone marrow-derived MSCs (BMSCs) were cultured for this study. Cell proliferation analysis was done with xCELLigence RTCA. After 48 h of cultivation, the cell culture medium was collected as MSC conditional medium containing mesenchymal stem cell-derived soluble factors (MDFs). Different concentrations of MDFs (12%, 25%, 50%, 75%, and 100%) were applied to the HUVEC cell line. Folic acid (25, 30, 50, 60, 75, 90, and 100 μM) was tested by application of three different groups (control, 25 μM folic acid, 625 μM folic acid inhibitors) for proliferation on the HUVEC cell line. The combined effects of folic acid and MDFs were tested on the HUVEC cell line with 25 μM folic acid and 50 μM MDFs. All data were statistically analyzed using SPSS 15.0 for Windows.

Results

Significant differences were observed between controls and cells treated with folic acid, as well as between controls and both folic acid and MDFs (P < 0.05). Among the treated groups, the fastest wound closure rate was seen in cells treated with both folic acid and MDFs.

Conclusion

The results show that both folic acid and MDFs increased the wound healing rate in HUVECs when they were used separately. The strongest benefits were seen in treatment using folic acid and MDFs together.

Mesenchymal Stem Cell-Based Therapy of Inflammatory Lung Diseases: Current Understanding and Future Perspectives

During acute or chronic lung injury, inappropriate immune response and/or aberrant repair process causes irreversible damage in lung tissue and most usually results in the development of fibrosis followed by decline in lung function. Inhaled corticosteroids and other anti-inflammatory drugs are very effective in patients with inflammatory lung disorders, but their long-term use is associated with severe side effects. Accordingly, new therapeutic agents that will attenuate ongoing inflammation and, at the same time, promote regeneration of injured alveolar epithelial cells are urgently needed. Mesenchymal stem cells (MSCs) are able to modulate proliferation, activation, and effector function of all immune cells that play an important role in the pathogenesis of acute and chronic inflammatory lung diseases. In addition to the suppression of lung-infiltrated immune cells, MSCs have potential to differentiate into alveolar epithelial cells in vitro and, accordingly, represent new players in cell-based therapy of inflammatory lung disorders. In this review article, we described molecular mechanisms involved in MSC-based therapy of acute and chronic pulmonary diseases and emphasized current knowledge and future perspectives related to the therapeutic application of MSCs in patients suffering from acute respiratory distress syndrome, pneumonia, asthma, chronic obstructive pulmonary diseases, and idiopathic pulmonary fibrosis.

Modulating autophagy in mesenchymal stem cells effectively protects against hypoxia- or ischemia-induced injury

In mammals, a basal level of autophagy, a self-eating cellular process, degrades cytosolic proteins and subcellular organelles in lysosomes to provide energy, recycles the cytoplasmic components, and regenerates cellular building blocks; thus, autophagy maintains cellular and tissue homeostasis in all eukaryotic cells. In general, adaptive autophagy increases when cells confront stressful conditions to improve the survival rate of the cells, while destructive autophagy is activated when the cellular stress is not manageable and elicits the regenerative capacity. Hypoxia-reoxygenation (H/R) injury and ischemia-reperfusion (I/R) injury initiate excessive autophagy and endoplasmic reticulum (ER) stress and consequently induce a string of damage in mammalian tissues or organs. Mesenchymal stem cell (MSC)-based therapy has yielded promising results in repairing H/R- or I/R-induced injury in various tissues. However, MSC transplantation in vivo must overcome the barriers including the low survival rate of transplanted stem cells, limited targeting capacity, and low grafting potency; therefore, much effort is needed to increase the survival and activity of MSCs in vivo. Modulating autophagy regulates the stemness and the anti-oxidative stress, anti-apoptosis, and pro-survival capacity of MSCs and can be applied to MSC-based therapy for repairing H/R- or I/R-induced cellular or tissue injury.

Mesenchymal stem cell therapy for the treatment of inflammatory diseases: Challenges, opportunities, and future perspectives

Mesenchymal stem cells (MSCs) are promising alternative agents for the treatment of inflammatory disorders due to their immunomodulatory functions, and several clinical trials on MSC-based products are currently being conducted. In this review, we discuss recent progress made on the use of MSCs as immunomodulatory agents, developmental challenges posed by MSC-based therapy, and the strategies being used to overcome these challenges. In this context, current understanding of the mechanisms responsible for MSC interactions with the immune system and the molecular responses of MSCs to inflammatory signals are discussed. The immunosuppressive activities of MSCs are initiated by cell-to-cell contact and the release of immuno-regulatory molecules. By doing so, MSCs can inhibit the proliferation and function of T cells, natural killer cells, B cells, and dendritic cells, and can also increase the proliferation of regulatory T cells. However, various problems, such as low transplanted cell viability, poor homing and engraftment into injured tissues, MSC heterogeneity, and lack of adequate information on optimum MSC doses impede clinical applications. On the other hand, it has been shown that the immunomodulatory activities and viabilities of MSCs might be enhanced by 3D-cultured systems, genetic modifications, preconditioning, and targeted-delivery.

Mesenchymal stem cell-based therapy of osteoarthritis: Current knowledge and future perspectives

Osteoarthritis (OA) is a chronic, prevalent, debilitating joint disease characterized by progressive cartilage degradation, subchondral bone remodeling, bone marrow lesions, meniscal damage, and synovitis. Innate immune cells (natural killer cells, macrophages, and mast cells) play the most important pathogenic role in the early inflammatory response, while cells of adaptive immunity (CD4 + Th1 lymphocytes and antibody producing B cells) significantly contribute to the development of chronic, relapsing course of inflammation in OA patients. Conventional therapy for OA is directed toward symptomatic treatment, mainly pain management, and is not able to promote regeneration of degenerated cartilage or to attenuate joint inflammation. Since articular cartilage, intra-articular ligaments, and menisci have no ability to heal, regeneration of these tissues remains one of the most important goals of new therapeutic approaches used for OA treatment. Due to their capacity for differentiation into chondrocytes and due to their immunomodulatory properties, mesenchymal stem cells (MSCs) have been the most extensively explored as new therapeutic agents in the cell-based therapy of OA. Simple acquisition, rapid proliferation, maintenance of differentiation potential after repeated passages in vitro, minor immunological rejection due to the low surface expression of major histocompatibility complex antigens, efficient engraftment and long-term coexistence in the host are the main characteristics of MSCs that enable their therapeutic use in OA. In this review article, we emphasized current knowledge and future perspectives regarding molecular and cellular mechanisms responsible for beneficial effects of autologous and allogeneic MSCs in the treatment of OA.

3D Bone Biomimetic Scaffolds for Basic and Translational Studies with Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are recognized as an attractive tool owing to their self-renewal and differentiation capacity, and their ability to secrete bioactive molecules and to regulate the behavior of neighboring cells within different tissues. Accumulating evidence demonstrates that cells prefer three-dimensional (3D) to 2D culture conditions, at least because the former are closer to their natural environment. Thus, for in vitro studies and in vivo utilization, great effort is being dedicated to the optimization of MSC 3D culture systems in view of achieving the intended performance. This implies understanding cell–biomaterial interactions and manipulating the physicochemical characteristics of biomimetic scaffolds to elicit a specific cell behavior. In the bone field, biomimetic scaffolds can be used as 3D structures, where MSCs can be seeded, expanded, and then implanted in vivo for bone repair or bioactive molecules release. Actually, the union of MSCs and biomaterial has been greatly improving the field of tissue regeneration. Here, we will provide some examples of recent advances in basic as well as translational research about MSC-seeded scaffold systems. Overall, the proliferation of tools for a range of applications witnesses a fruitful collaboration among different branches of the scientific community.

Mesenchymal Stromal Cell-Seeded Biomimetic Scaffolds as a Factory of Soluble RANKL in Rankl-Deficient Osteopetrosis

Biomimetic scaffolds are extremely versatile in terms of chemical composition and physical properties, which can be defined to accomplish specific applications. One property that can be added is the production/release of bioactive soluble factors, either directly from the biomaterial, or from cells embedded within the biomaterial. We reasoned that pursuing this strategy would be appropriate to setup a cell‐based therapy for RANKL‐deficient autosomal recessive osteopetrosis, a very rare skeletal genetic disease in which lack of the essential osteoclastogenic factor RANKL impedes osteoclast formation. The exogenously administered RANKL cytokine is effective in achieving osteoclast formation and function in vitro and in vivo, thus, we produced murine Rankl^−/− mesenchymal stromal cells (MSCs) overexpressing human soluble RANKL (hsRL) following lentiviral transduction (LVhsRL). Here, we described a three‐dimensional (3D) culture system based on a magnesium‐doped hydroxyapatite/collagen I (MgHA/Col) biocompatible scaffold closely reproducing bone physicochemical properties. MgHA/Col‐seeded murine MSCs showed improved properties, as compared to two‐dimensional (2D) culture, in terms of proliferation and hsRL production, with respect to LVhsRL‐transduced cells. When implanted subcutaneously in Rankl^−/− mice, these cell constructs were well tolerated, colonized by host cells, and intensely vascularized. Of note, in the bone of Rankl^−/− mice that carried scaffolds with either WT or LVhsRL‐transduced Rankl^−/− MSCs, we specifically observed formation of TRAP⁺ cells, likely due to sRL released from the scaffolds into circulation. Thus, our strategy proved to have the potential to elicit an effect on the bone; further work is required to maximize these benefits and achieve improvements of the skeletal pathology in the treated Rankl^−/− mice. Stem Cells Translational Medicine2019;8:22–34

Transcriptomic analysis of lung tissues after hUC-MSCs and FTY720 treatment of lipopolysaccharide-induced acute lung injury in mouse models

Acute lung injury and acute respiratory distress syndrome (ALI/ARDS) refer to acute and progressive hypoxic respiratory failure caused by non-cardiogenic factors, which is a common condition occurring in critically ill patients with widespread pulmonary inflammation. Use of a single medication or target cannot treat ALI/ARDS. Mesenchymal stem cells (MSCs) and FTY720, as an analogue of sphingosine-1-phosphate (S1P), can mitigate lipopolysaccharide (LPS)-induced inflammatory lung injury. In this investigation, the clinical efficacy of MSCs alone, FTY720 alone, and a MSC and FTY720 combination in the treatment of LPS-induced lung injury was evaluated in mouse models. The experimental results demonstrated that both MSCs and FTY720 alleviate lung injuries in mice. The combined application of MSCs and FTY720 yielded higher clinical efficacy in mitigating lung injuries compared with use of MSCs or FTY720 alone. Transcriptomic analysis was performed using an Agilent gene expression chip. By analyzing the differences in gene expression of lung tissues between treated and non-treated ALI/ARDS mice, Gene Ontology and Pathway terms related to ALI/ARDS treatment were identified. Moreover, the target genes which might play a pivotal role in the treatment of ALI/ARDS were also detected, thus providing a theoretical basis for multi-target or multi-drug combined treatment of ALI/ARDS and lay a solid foundation for clinical treatment of ALI/ARDS.