Immunomodulatory effects of human umbilical cord Wharton's jelly-derived mesenchymal stem cells on differentiation, maturation and endocytosis of monocyte-derived dendritic cells

Immunomodulatory effects of mesenchymal stem cells in peripheral nerve injury

Various immune cells and cytokines are present in the aftermath of peripheral nerve injuries (PNI), and coordination of the local inflammatory response is of great significance for the recovery of PNI. Mesenchymal stem cells (MSCs) exhibit immunosuppressive and anti-inflammatory abilities which can accelerate tissue regeneration and attenuate inflammation, but the role of MSCs in the regulation of the local inflammatory microenvironment after PNI has not been widely studied. Here, we summarize the known interactions between MSCs, immune cells, and inflammatory cytokines following PNI with a focus on the immunosuppressive role of MSCs. We also discuss the immunomodulatory potential of MSC-derived extracellular vesicles as a new cell-free treatment for PNI.

Multipotent Mesenchymal Stromal Cells in Rheumatoid Arthritis and Systemic Lupus Erythematosus; From a Leading Role in Pathogenesis to Potential Therapeutic Saviors?

The pathogenesis of the autoimmune rheumatological diseases including rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) is complex with the involvement of several immune cell populations spanning both innate and adaptive immunity including different T-lymphocyte subsets and monocyte/macrophage lineage cells. Despite therapeutic advances in RA and SLE, some patients have persistent and stubbornly refractory disease. Herein, we discuss stromal cells' dual role, including multipotent mesenchymal stromal cells (MSCs) also used to be known as mesenchymal stem cells as potential protagonists in RA and SLE pathology and as potential therapeutic vehicles. Joint MSCs from different niches may exhibit prominent pro-inflammatory effects in experimental RA models directly contributing to cartilage damage. These stromal cells may also be key regulators of the immune system in SLE. Despite these pro-inflammatory roles, MSCs may be immunomodulatory and have potential therapeutic value to modulate immune responses favorably in these autoimmune conditions. In this review, the complex role and interactions between MSCs and the haematopoietically derived immune cells in RA and SLE are discussed. The harnessing of MSC immunomodulatory effects by contact-dependent and independent mechanisms, including MSC secretome and extracellular vesicles, is discussed in relation to RA and SLE considering the stromal immune microenvironment in the diseased joints. Data from translational studies employing MSC infusion therapy against inflammation in other settings are contextualized relative to the rheumatological setting. Although safety and proof of concept studies exist in RA and SLE supporting experimental and laboratory data, robust phase 3 clinical trial data in therapy-resistant RA and SLE is still lacking.

Hydrogen Peroxide Preconditioning Promotes Protective Effects of Umbilical Cord Vein Mesenchymal Stem Cells in Experimental Pulmonary Fibrosis

Purpose: Idiopathic pulmonary fibrosis (IPF) is a progressive lung disorder with few available treatments. Mesenchymal stem cell therapy (MSCT), an innovative approach, has high therapeutic potential when used to treat IPF. According to recent data, preconditioning of MSCs can improve their therapeutic effects. Our research focuses on investigating the anti-inflammatory and antifibrotic effects of H2 O2 -preconditioned MSCs (p-MSCs) on mice with bleomycin-induced pulmonary fibrosis (PF). Methods: Eight-week-old male C57BL/6 mice were induced with PF by intratracheal (IT) instillation of bleomycin (4 U/kg). Human umbilical cord vein-derived MSCs (hUCV-MSCs) were isolated and exposed to a sub-lethal concentration (15 μM for 24 h) of H2 O2 in vitro. One week following the injection of bleomycin, 2×105 MSCs or p-MSCs were injected (IT) into the experimental PF. The survival rate and weight of mice were recorded, and 14 days after MSCs injection, all mice were sacrificed. Lung tissue was removed from these mice to examine the myeloperoxidase (MPO) activity, histopathological changes (hematoxylin-eosin and Masson's trichrome) and expression of transforming growth factor beta 1 (TGF-β1) and alpha-smooth muscle actin (α-SMA) through immunohistochemistry (IHC) staining. Results: Compared to the PF+MSC group, p-MSCs transplantation results in significantly decreased connective tissue (P<0.05) and collagen deposition. Additionally, it is determined that lung tissue in the PF+pMSC group has increased alveolar space (P<0.05) and diminished expression of TGF-β1 and α-SMA. Conclusion: The results demonstrate that MSCT using p-MSCs decreases inflammatory and fibrotic factors in bleomycin-induced PF, while also able to increase the therapeutic potency of MSCT in IPF.

Perinatal Mesenchymal Stromal Cells and Their Possible Contribution to Fetal-Maternal Tolerance

During pregnancy, a successful coexistence between the mother and the semi-allogenic fetus occurs which requires a dynamic immune system to guarantee an efficient immune protection against possible infections and tolerance toward fetal antigens. The mechanism of fetal-maternal tolerance is still an open question. There is growing in vitro and in vivo evidence that mesenchymal stromal cells (MSC) which are present in perinatal tissues have a prominent role in generating a functional microenvironment critical to a successful pregnancy. This review highlights the immunomodulatory properties of perinatal MSC and their impact on the major immune cell subsets present in the uterus during pregnancy, such as natural killer cells, antigen-presenting cells (macrophages and dendritic cells), and T cells. Here, we discuss the current understanding and the possible contribution of perinatal MSC in the establishment of fetal-maternal tolerance, providing a new perspective on the physiology of gestation.

Role of CCR7 on dendritic cell‑mediated immune tolerance in the airways of allergy‑induced asthmatic rats

Dendritic cells (DCs) have an important role in initiating and maintaining the immune inflammatory response in allergic asthma, and CC chemokine receptor 7 (CCR7) is directly involved in the pathogenesis of DC- and T cell-mediated allergic asthma. The present study aimed to investigate the effects of CCR7 on DC-mediated immune tolerance in allergic asthma. In the present study, bone marrow-derived DCs were transfected with an adenovirus encoding the rat CCR7 gene or a short hairpin RNA targeting CCR7 (sh-CCR7). Rats injected with DCs overexpressing CCR7 or presenting CCR7 knockdown were examined. After the rats were injected with DCs via the tail vein, bronchoalveolar lavage fluid was collected to assess its cellular composition. The protein expression levels of CCR7 in DCs were determined using immunohistochemistry and western blot analysis. The protein expression levels of interferon-γ (IFN-γ), interleukin-4 (IL-4), IL-10, IL-12, transforming growth factor-β (TGF-β) and immunoglobulin E (IgE) were determined by ELISA. Compared with the control group, the protein expression level of CCR7 was significantly higher in the CCR7 overexpression group and significantly lower in sh-CCR7 group. Similarly, the number of DCs was higher in the CCR7 overexpression group and lower in the sh-CCR7 group. The protein expression levels of IL-10 and TGF-β were significantly lower in the CCR7 overexpression group and higher in the sh-CCR7 group. In addition, the expression levels of IL-4, IL-12, IFN-γ and IgE were higher in the CCR7 overexpression group and lower in the sh-CCR7 group. The present results suggested that the role of cytokines and IgE in immune inflammation and immune tolerance in allergic asthma may be associated with the expression level of CCR7 in DCs, suggesting that CCR7 may serve a role in DC-mediated immune tolerance in allergic asthma.

Mesenchymal Stem Cells Derived and Cultured from Glioblastoma Multiforme Increase Tregs, Downregulate Th17, and Induce the Tolerogenic Phenotype of Monocyte-Derived Cells

Mesenchymal stem cells (MSCs) possess immunosuppressive properties and have been described in the tumor microenvironment of glioblastoma multiforme (GBM). This manuscript has two major topics—first, to describe isolated and cultured MSCs derived from GBM (GB-MSCs) and second, to examine their in vitro immunosuppressive capacity. Our results display cells with morphology and phenotype, clonogenic ability, and osteogenic potential, typical for MSCs. Furthermore, the cultured cells show intracellular expression of the neural markers Nestin and GFAP. They express PD-L1 and secrete TGFβ, CCL-2, PGE2, IL-6, and sVEGF. Coculturing of GB-MSCs with PBMCs isolated from healthy donors results in a decreased percentage of Th17 lymphocytes and an increased percentage of Tregs. Regarding the impact of GB-MSCs on monocytes, we establish an augmented expression of CD14 and CD86 along with diminished expression of HLA-DR and CD80, which is associated with tolerogenic phenotype monocyte-derived cells. In conclusion, our results describe in detail GBM-derived and cultured cells that meet the criteria for MSCs but at the same time express Nestin and GFAP. GB-MSCs express and secrete suppressive molecules, influencing in vitro T cells and monocytes, and are probably another factor involved in the immune suppression exerted by GBM.

Establishment of malignantly transformed dendritic cell line SU3-ihDCTC induced by Glioma stem cells and study on its sensitivity to resveratrol

BACKGROUND

As a factor contributing to the tumor cell drug resistance, tumor microenvironment (TME) is being paid increasingly attention. However, the drug resistance of malignantly transformed cells in TME has rarely been revealed. This paper is designed to investigate the sensitivity of malignantly transformed cell line (ihDCTC) induced by glioma stem cells (GSCs) in TME to chemotherapeutic drugs.

METHODS

(1) Establishment of ihDCTC cell line,The bone marrow cells from enhanced green fluorescent protein (EGFP) transgenic nude mice were employed to culture the dendritic cells (DCs) in vitro, which were then co-cultured with red fluorescence protein (RFP) transgenic GSCs (SU3) to obtain ihDCTC (2) Res and Cis were used to intervene in the growth of abovemetioned cell lines in vitro and Res treated in bearing ihDCTC tumor mice, followed by evaluating their drug sensitivity and changes in key signaling proteins via half maximal inhibitory concentration (IC50), tumor mass and immunostaining method.

RESULTS

(1) ihDCTC could express CD11c and CD80 as well as possessed immortalized potential, heteroploid chromosomes and high tumorigenicity in nude mice in vivo. (2) At 24 h, 48 h and 72 h, the IC50 value of ihDCTC treated with Cis was 3.62, 3.25 and 2.10 times higher than that of SU3, while the IC50 value of ihDCTC treated with Res was 0.03, 0.47 and 1.19 times as much as that of SU3; (3) The xenograft mass (g) in vivo in the control, Res, Cis and Res + Cis groups were 1.44 ± 0.19, 0.45 ± 0.12, 0.94 ± 0.80 and 0.68 ± 0.35(x ± s) respectively. The expression levels of IL-6, p-STAT3 and NF-κB proteins in the xenograft tissue were significantly reduced only in the Res treatment group.

CONCLUSION

In vitro co-culture with GSC can induce the malignant transformation of bone marrow derived dendritic cells, on the one hand, ihDCTC shows higher drug resistance to the traditional chemotherapeutic drug Cis than GSCs, but, on the other hand, appears to be more sensitive to Res than GSCs. Therefore, our findings provide a broader vision not only for the further study on the correlation between TME and tumor drug resistance but also for the exploration of Res anti-cancer value.

Establishment of malignantly transformed dendritic cell line SU3-ihDCTC induced by Glioma stem cells and study on its sensitivity to resveratrol

BACKGROUND

As a factor contributing to the tumor cell drug resistance, tumor microenvironment (TME) is being paid increasingly attention. However, the drug resistance of malignantly transformed cells in TME has rarely been revealed. This paper is designed to investigate the sensitivity of malignantly transformed cell line (ihDCTC) induced by glioma stem cells (GSCs) in TME to chemotherapeutic drugs.

METHODS

(1) Establishment of ihDCTC cell line,The bone marrow cells from enhanced green fluorescent protein (EGFP) transgenic nude mice were employed to culture the dendritic cells (DCs) in vitro, which were then co-cultured with red fluorescence protein (RFP) transgenic GSCs (SU3) to obtain ihDCTC (2) Res and Cis were used to intervene in the growth of abovemetioned cell lines in vitro and Res treated in bearing ihDCTC tumor mice, followed by evaluating their drug sensitivity and changes in key signaling proteins via half maximal inhibitory concentration (IC₅₀), tumor mass and immunostaining method.

RESULTS

(1) ihDCTC could express CD11c and CD80 as well as possessed immortalized potential, heteroploid chromosomes and high tumorigenicity in nude mice in vivo. (2) At 24 h, 48 h and 72 h, the IC₅₀ value of ihDCTC treated with Cis was 3.62, 3.25 and 2.10 times higher than that of SU3, while the IC₅₀ value of ihDCTC treated with Res was 0.03, 0.47 and 1.19 times as much as that of SU3; (3) The xenograft mass (g) in vivo in the control, Res, Cis and Res + Cis groups were 1.44 ± 0.19, 0.45 ± 0.12, 0.94 ± 0.80 and 0.68 ± 0.35(x ± s) respectively. The expression levels of IL-6, p-STAT3 and NF-κB proteins in the xenograft tissue were significantly reduced only in the Res treatment group.

CONCLUSION

In vitro co-culture with GSC can induce the malignant transformation of bone marrow derived dendritic cells, on the one hand, ihDCTC shows higher drug resistance to the traditional chemotherapeutic drug Cis than GSCs, but, on the other hand, appears to be more sensitive to Res than GSCs. Therefore, our findings provide a broader vision not only for the further study on the correlation between TME and tumor drug resistance but also for the exploration of Res anti-cancer value.

Human mesenchymal stromal cell-secreted lactate induces M2-macrophage differentiation by metabolic reprogramming

Human mesenchymal stromal cells (MSC) have been shown to dampen immune response and promote tissue repair, but the underlying mechanisms are still under investigation. Herein, we demonstrate that umbilical cord-derived MSC (UC-MSC) alter the phenotype and function of monocyte-derived dendritic cells (DC) through lactate-mediated metabolic reprogramming. UC-MSC can secrete large quantities of lactate and, when present during monocyte-to-DC differentiation, induce instead the acquisition of M2-macrophage features in terms of morphology, surface markers, migratory properties and antigen presentation capacity. Microarray expression profiling indicates that UC-MSC modify the expression of metabolic-related genes and induce a M2-macrophage expression signature. Importantly, monocyte-derived DC obtained in presence of UC-MSC, polarize naïve allogeneic CD4⁺ T-cells into Th2 cells. Treatment of UC-MSC with an inhibitor of lactate dehydrogenase strongly decreases lactate concentration in culture supernatant and abrogates the effect on monocyte-to-DC differentiation. Metabolic analysis further revealed that UC-MSC decrease oxidative phosphorylation in differentiating monocytes while strongly increasing the spare respiratory capacity proportional to the amount of secreted lactate. Because both MSC and monocytes are recruited in vivo at the site of tissue damage and inflammation, we propose the local increase of lactate concentration induced by UC-MSC and the consequent enrichment in M2-macrophage generation as a mechanism to achieve immunomodulation.

Comparative Ability of Mesenchymal Stromal Cells from Different Tissues to Limit Neutrophil Recruitment to Inflamed Endothelium

Mesenchymal stromal cells (MSC) are tissue-resident stromal cells capable of modulating immune responses, including leukocyte recruitment by endothelial cells (EC). However, the comparative potency of MSC from different sources in suppressing recruitment, and the necessity for close contact with endothelium remain uncertain, although these factors have implications for use of MSC in therapy. We thus compared the effects of MSC isolated from bone marrow, Wharton's jelly, and trabecular bone on neutrophil recruitment to cytokine-stimulated EC, using co-culture models with different degrees of proximity between MSC and EC. All types of MSC suppressed neutrophil adhesion to inflamed endothelium but not neutrophil transmigration, whether directly incorporated into endothelial monolayers or separated from them by thin micropore filters. Further increase in the separation of the two cell types tended to reduce efficacy, although this diminution was least for the bone marrow MSC. Immuno-protective effects of MSC were also diminished with repeated passage; with BMMSC, but not WJMSC, completing losing their suppressive effect by passage 7. Conditioned media from all co-cultures suppressed neutrophil recruitment, and IL-6 was identified as a common bioactive mediator. These results suggest endogenous MSC have a homeostatic role in limiting inflammatory leukocyte infiltration in a range of tissues. Since released soluble mediators might have effects locally or remotely, infusion of MSC into blood or direct injection into target organs might be efficacious, but in either case, cross-talk between EC and MSC appears necessary.

Human Chorionic Villous Mesenchymal Stem Cells Modify the Functions of Human Dendritic Cells, and Induce an Anti-Inflammatory Phenotype in CD1+ Dendritic Cells

BACKGROUND

Mesenchymal stem cells derived from the chorionic villi of human term placenta (pMSCs) have drawn considerable interest because of their multipotent differentiation potential and their immunomodulatory capacity. These properties are the foundation for their clinical application in the fields of stem cell transplantation and regenerative medicine. Previously, we showed that pMSCs induce an anti-inflammatory phenotype in human macrophages. In this study, we determined whether pMSCs modify the differentiation and maturation of human monocytes into dendritic cells (DCs). The consequences on dendritic function and on T cell proliferation were also investigated.

METHODS

Interleukin-4 (IL-4) and granulocyte-macrophage colony stimulating factor (GM-CSF) were used to stimulate the differentiation of monocytes into immature dendritic cells (iDCs), which were subsequently co-cultured with pMSCs. Lipopolysaccharide (LPS) was used to induce maturation of iDCs into mature dendritic cells (mDCs). Flow cytometry and enzyme-linked immunosorbent assays (ELISA) were used to quantify the effect pMSC co-culturing on DC differentiation using CD1a, a distinctive marker of DCs, as well as other molecules important in the immune functions of DCs. The phagocytic activity of iDCs co-cultured with pMSCs, and the effects of iDCs and mDC stimulation on T cell proliferation, were also investigated.

RESULTS

Monocyte differentiation into iDCs was inhibited when co-cultured with pMSCs and maturation of iDCs by LPS treatment was also prevented in the presence of pMSCs as demonstrated by reduced expression of CD1a and CD83, respectively. The inhibitory effect of pMSCs on iDC differentiation was dose dependent. In addition, pMSC co-culture with iDCs and mDCs resulted in both phenotypic and functional changes as shown by reduced expression of costimulatory molecules (CD40, CD80, CD83 and CD86) and reduced capacity to stimulate CD4(+) T cell proliferation. In addition, pMSC co-culture increased the surface expression of major histocompatibility complex (MHC-II) molecules on iDCs but decreased MHC-II expression on mDCs. Moreover, pMSC co-culture with iDCs or mDCs increased the expression of immunosuppressive molecules [B7H3, B7H4, CD273, CD274 and indoleamine-pyrrole 2,3-dioxygenase (IDO). Additionally, the secretion of IL-12 and IL-23 by iDCs and mDCs co-cultured with pMSCs was decreased. Furthermore, pMSC co-culture with mDCs decreased the secretion of IL-12 and INF-γ whilst increasing the secretion of IL-10 in a T cell proliferation experiment. Finally, pMSC co-culture with iDCs induced the phagocytic activity of iDCs.

CONCLUSIONS

We have shown that pMSCs have an inhibitory effect on the differentiation, maturation and function of DCs, as well as on the proliferation of T cells, suggesting that pMSCs can control the immune responses at multiple levels.

Comparing the Immunomodulatory Properties of Bone Marrow, Adipose Tissue, and Birth-Associated Tissue Mesenchymal Stromal Cells

Mesenchymal stromal cells (MSC) have gained immense attraction in regenerative medicine, tissue engineering, and immunotherapy. This is based on their differentiation potential and the supply of pro-regenerative and immunomodulatory signals. MSC can be isolated from a multitude of tissue sources, but mainly bone marrow, adipose tissue, and birth-associated tissues (e.g., umbilical cord, cord blood, placenta) appear to be relevant for clinical translation in immune-mediated disorders. However, only a few studies directly compared the immunomodulatory potency of MSC from different tissue sources. This review compiles the current literature regarding the similarities and differences between these three sources for MSCs with a special focus on their immunomodulatory effects on T-lymphocyte subsets and monocytes, macrophages, and dendritic cells.

The Long Path of Human Placenta, and Its Derivatives, in Regenerative Medicine

In the 1800s, a baby born with a caul, a remnant of the amniotic sack or fetal membranes, was thought to be lucky, special, or protected. Over time, fetal membranes lost their legendary power and were soon considered nothing more than biological waste after birth. However, placenta tissues have reclaimed their potential and since the early 1900s an increasing body of evidence has shown that these tissues have clinical benefits in a wide range of wound repair and surgical applications. Nowadays, there is a concerted effort to understand the mechanisms underlying the beneficial effects of placental tissues, and, more recently, cells derived thereof. This review will summarize the historical and current clinical applications of human placental tissues, and cells isolated from these tissues, and discuss some mechanisms thought to be responsible for the therapeutic effects observed after tissue and/or cell transplantation.

Human Mesenchymal Stem Cells Reendothelialize Porcine Heart Valve Scaffolds: Novel Perspectives in Heart Valve Tissue Engineering

Heart valve diseases are usually treated by surgical intervention addressed for the replacement of the damaged valve with a biosynthetic or mechanical prosthesis. Although this approach guarantees a good quality of life for patients, it is not free from drawbacks (structural deterioration, nonstructural dysfunction, and reintervention). To overcome these limitations, the heart valve tissue engineering (HVTE) is developing new strategies to synthesize novel types of valve substitutes, by identifying efficient sources of both ideal scaffolds and cells. In particular, a natural matrix, able to interact with cellular components, appears to be a suitable solution. On the other hand, the well-known Wharton's jelly mesenchymal stem cells (WJ-MSCs) plasticity, regenerative abilities, and their immunomodulatory capacities make them highly promising for HVTE applications. In the present study, we investigated the possibility to use porcine valve matrix to regenerate in vitro the valve endothelium by WJ-MSCs differentiated along the endothelial lineage, paralleled with human umbilical vein endothelial cells (HUVECs), used as positive control. Here, we were able to successfully decellularize porcine heart valves, which were then recellularized with both differentiated-WJ-MSCs and HUVECs. Data demonstrated that both cell types were able to reconstitute a cellular monolayer. Cells were able to positively interact with the natural matrix and demonstrated the surface expression of typical endothelial markers. Altogether, these data suggest that the interaction between a biological scaffold and WJ-MSCs allows the regeneration of a morphologically well-structured endothelium, opening new perspectives in the field of HVTE.

Human Bone Marrow-Derived Mesenchymal Stromal Cells Differentially Inhibit Cytokine Production by Peripheral Blood Monocytes Subpopulations and Myeloid Dendritic Cells

The immunosuppressive properties of mesenchymal stromal/stem cells (MSC) rendered them an attractive therapeutic approach for immune disorders and an increasing body of evidence demonstrated their clinical value. However, the influence of MSC on the function of specific immune cell populations, namely, monocyte subpopulations, is not well elucidated. Here, we investigated the influence of human bone marrow MSC on the cytokine and chemokine expression by peripheral blood classical, intermediate and nonclassical monocytes, and myeloid dendritic cells (mDC), stimulated with lipopolysaccharide plus interferon (IFN)γ. We found that MSC effectively inhibit tumor necrosis factor- (TNF-) α and macrophage inflammatory protein- (MIP-) 1β protein expression in monocytes and mDC, without suppressing CCR7 and CD83 protein expression. Interestingly, mDC exhibited the highest degree of inhibition, for both TNF-α and MIP-1β, whereas the reduction of TNF-α expression was less marked for nonclassical monocytes. Similarly, MSC decreased mRNA levels of interleukin- (IL-) 1β and IL-6 in classical monocytes, CCL3, CCL5, CXCL9, and CXCL10 in classical and nonclassical monocytes, and IL-1β and CXCL10 in mDC. MSC do not impair the expression of maturation markers in monocytes and mDC under our experimental conditions; nevertheless, they hamper the proinflammatory function of monocytes and mDC, which may impede the development of inflammatory immune responses.

Application of Umbilical Cord Blood Derived Stem Cells in Diseases of the Nervous System

Umbilical cord blood (UCB) derived multipotent stem cells are capable of giving rise hematopoietic, epithelial, endothelial and neural progenitor cells. Thus suggested to significantly improve graft-versus-host disease and represent the distinctive therapeutic option for several malignant and non-malignant diseases. Recent advances in strategies to isolate, expand and shorten the timing of UCB stem cells engraftment have tremendously improved the efficacy of transplantations. Nervous system has limited regenerative potential in disease conditions such as cancer, neurodegeneration, stroke, and several neural injuries. This review focuses on application of UCB derived stem/progenitor cells in aforementioned pathological conditions. We have discussed the possible attempts to make use of UCB therapies to generate neural cells and tissues with developmental and functional similarities to neuronal cells. In addition, emerging applications of UCB derived AC133+ (CD133+) endothelial progenitor cells (EPCs) as imaging probe, regenerative agent, and gene delivery vehicle are mentioned that will further improve the understanding of use of UCB cells in therapeutic modalities. However, safe and effective protocols for cell transplantations are still required for therapeutic efficacy.