New Cell-Based Therapy Paradigm: Induction of Bone Marrow-Derived Multipotent Mesenchymal Stromal Cells into Pro-Inflammatory MSC1 and Anti-inflammatory MSC2 Phenotypes

Lovastatin Combination Therapy Increases the Survival and Proliferation of Rat Bone Marrow-Derived Mesenchymal Stem Cells Against the Inflammatory Activity of Lipopolysaccharide

Oxidative stress hurts the survival of transplanted mesenchymal stem cells (MSCs). Lipopolysaccharide (LPS) preconditioning inhibits apoptotic death in MSCs. Also, Lovastatin's protective effect was reported on MSCs. Here, we investigated the potential of LPS and Lovastatin combination therapy on the survival and proliferation of MSCs. MSCs harvested from adult rats (240-260 g) femur and tibia bone marrow. Third passage MSCs were divided into 6 groups control group, LPS, LPS + Lovastatin (10 and 15 µM), and Lovastatin (10 and 15 µM). Cell survival and proliferation were assessed using an MTT assay 24 h after LPS, Lovastatin, or LPS + Lovastatin treatment. Also, Malondialdehyde (MDA) as a lipid peroxidation marker and antioxidant enzymes such as Glutathione peroxidase (GPX) and Superoxide dismutase (SOD) activity levels evaluated. Finally, the expression level of tumor protein P53 (P53) and octamer-binding transcription factor 4 (OCT4) genes were measured by qRT-PCR test. Lovastatin 10 μM potentiated proliferation and survival of MSCs. It can increase the activity of GPX and SOD. 10 µM Lovastatin could not affect MDA amounts but decreased the expression levels of P53 and Oct4 significantly. Nevertheless, treatment with LPS reduced the survival and proliferation of MSCs, along with a significant reduction in GPX activity. LPS + Lovastatin could increase SOD activity, however, GPX enzyme activity and MSCs proliferation did not change so, and it was not effective. We propose Lovastatin at the dose of 10 µM as a suitable combination agent to increase the survival and proliferation of MSCs in oxidative stress conditions.

Advances in mesenchymal stromal cell therapy for acute lung injury/acute respiratory distress syndrome

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) develops rapidly and has high mortality. ALI/ARDS is mainly manifested as acute or progressive hypoxic respiratory failure. At present, there is no effective clinical intervention for the treatment of ALI/ARDS. Mesenchymal stromal cells (MSCs) show promise for ALI/ARDS treatment due to their biological characteristics, easy cultivation, low immunogenicity, and abundant sources. The therapeutic mechanisms of MSCs in diseases are related to their homing capability, multidirectional differentiation, anti-inflammatory effect, paracrine signaling, macrophage polarization, the polarization of the MSCs themselves, and MSCs-derived exosomes. In this review, we discuss the pathogenesis of ALI/ARDS along with the biological characteristics and mechanisms of MSCs in the treatment of ALI/ARDS.

Therapeutic Mesenchymal Stem/Stromal Cells: Value, Challenges and Optimization

Cellular therapy aims to replace damaged resident cells by restoring cellular and molecular environments suitable for tissue repair and regeneration. Among several candidates, mesenchymal stem/stromal cells (MSCs) represent a critical component of stromal niches known to be involved in tissue homeostasis. In vitro, MSCs appear as fibroblast-like plastic adherent cells regardless of the tissue source. The therapeutic value of MSCs is being explored in several conditions, including immunological, inflammatory and degenerative diseases, as well as cancer. An improved understanding of their origin and function would facilitate their clinical use. The stemness of MSCs is still debated and requires further study. Several terms have been used to designate MSCs, although consensual nomenclature has yet to be determined. The presence of distinct markers may facilitate the identification and isolation of specific subpopulations of MSCs. Regarding their therapeutic properties, the mechanisms underlying their immune and trophic effects imply the secretion of various mediators rather than direct cellular contact. These mediators can be packaged in extracellular vesicles, thus paving the way to exploit therapeutic cell-free products derived from MSCs. Of importance, the function of MSCs and their secretome are significantly sensitive to their environment. Several features, such as culture conditions, delivery method, therapeutic dose and the immunobiology of MSCs, may influence their clinical outcomes. In this review, we will summarize recent findings related to MSC properties. We will also discuss the main preclinical and clinical challenges that may influence the therapeutic value of MSCs and discuss some optimization strategies.

Age-Related Changes in the Inflammatory Status of Human Mesenchymal Stem Cells: Implications for Cell Therapy

Human mesenchymal stem/stromal cell (hMSC)-based cell therapies are promising for treating a variety of diseases. The unique immunomodulatory properties of hMSCs have extended their therapeutic potential beyond tissue regeneration. However, extensive pre-clinical culture expansion inevitably drives cells toward replicative “aging” and a consequent decline in quality. These “in vitro-aged” hMSCs resemble biologically aged cells, which have been reported to show senescence signatures, diminished immunosuppressive capacity, and weakened regenerative potential as well as pro-inflammatory features. In this review, we have surveyed the literature to explore the intimate relationship between the inflammatory status of hMSCs and their in vitro aging process. We posit that a shift from an anti-inflammatory to a pro-inflammatory phenotype of culture-expanded hMSCs contributes to a deterioration in their therapeutic efficacy. Potential molecular and cellular mechanisms underpinning this phenomenon have been discussed. We have also highlighted studies that leverage these mechanisms to make culture-expanded hMSCs more amenable for clinical use.

•

Aged MSCs have reduced immunosuppressive potential

•

Chronic inflammatory microenvironments can exacerbate MSC senescence and aging

•

The immunomodulatory potential of MSCs should be assessed prior to clinical use

•

MSC immunomodulatory properties may be modified in vitro by bioengineering means

Analysis of Hub Genes Involved in Distinction Between Aged and Fetal Bone Marrow Mesenchymal Stem Cells by Robust Rank Aggregation and Multiple Functional Annotation Methods

Stem cells from fetal tissue protect against aging and possess greater proliferative capacity than their adult counterparts. These cells can more readily expand in vitro and senesce later in culture. However, the underlying molecular mechanisms for these differences are still not fully understood. In this study, we used a robust rank aggregation (RRA) method to discover robust differentially expressed genes (DEGs) between fetal bone marrow mesenchymal stem cells (fMSCs) and aged adult bone marrow mesenchymal stem cells (aMSCs). Multiple methods, including gene set enrichment analysis (GSEA), Gene Ontology (GO) analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed for functional annotation of the robust DEGs, and the results were visualized using the R software. The hub genes and other genes with which they interacted directly were detected by protein–protein interaction (PPI) network analysis. Correlation of gene expression was measured by Pearson correlation coefficient. A total of 388 up-regulated and 289 down-regulated DEGs were identified between aMSCs and fMSCs. We found that the down-regulated genes were mainly involved in the cell cycle, telomerase activity, and stem cell proliferation. The up-regulated DEGs were associated with cell adhesion molecules, extracellular matrix (ECM)–receptor interactions, and the immune response. We screened out four hub genes, MYC, KIF20A, HLA-DRA, and HLA-DPA1, through PPI-network analysis. The MYC gene was negatively correlated with TXNIP, an age-related gene, and KIF20A was extensively involved in the cell cycle. The results suggested that MSCs derived from the bone marrow of an elderly donor present a pro-inflammatory phenotype compared with that of fMSCs, and the HLA-DRA and HLA-DPA1 genes are related to the immune response. These findings provide new insights into the differences between aMSCs and fMSCs and may suggest novel strategies for ex vivo expansion and application of adult MSCs.

The Use of Pulsed Electromagnetic Field to Modulate Inflammation and Improve Tissue Regeneration: A Review

Pulsed electromagnetic field (PEMF) is emerging as innovative treatment for regulation of inflammation, which could have significant effects on tissue regeneration. PEMF modulates inflammatory processes through the regulation of pro- and anti-inflammatory cytokine secretion during different stages of inflammatory response. Consistent outcomes in studies involving animal and human tissue have shown promise for the use of PEMF as an alternative or complementary treatment to pharmaceutical therapies. Thus, PEMF treatment could provide a novel nonpharmaceutical means of modulating inflammation in injured tissues resulting in enhanced functional recovery. This review examines the effect of PEMF on immunomodulatory cells (e.g., mesenchymal stem/stromal cells [MSCs] and macrophages [MΦ]) to better understand the potential for PEMF therapy to modulate inflammatory signaling pathways and improve tissue regeneration. This review cites published data that support the use of PEMF to improve tissue regeneration. Our studies included herein confirm anti-inflammatory effects of PEMF on MSCs and MΦ.

Low level laser (LLL) attenuate LPS-induced inflammatory responses in mesenchymal stem cells via the suppression of NF-κB signaling pathway in vitro

Background

Considering promising results in animal models and patients, therapeutic use of MSCs for immune disease is likely to undergo continued evaluation. Low-lever laser (LLL) has been widely applied to retard the inflammatory reaction. LLL treatment can potentially be applied in anti-inflammatory therapy followed by stem cell therapy.

Aim of the study

The purpose of this study was to investigate the effect of LLL (660 nm) on the inflammatory reaction induced by LPS in human adipose derived mesenchymal stem cells (hADSCs) and pertinent mechanism.

Materials and methods

Anti-inflammatory activity of LLL was investigated by LPS-induced mesenchymal stem cells. The production and expression of pro-inflammatory cytokines were evaluated by ELISA kits and RT-qPCR. Nuclear translocation of NF-κB was indicated by immunofluorescent staining. Phosphorylation status of NF-κB p65 and IκBα were illustrated by western blot assay. ROS generation was measured with CM-H2DCFDA, and NO secretion was determined by DAF-FM. We studied surface expression of lymphocyte activation markers when Purified peripheral blood mononuclear cell (PBMC) were activated by phytohaemagglutinin (PHA) in the presence of 3 types of treated MSCs.

Results

LLL reduced the secretion of IL-1β, IL-6, IL8, ROS and NO in LPS treated MSCs. Immunofluorescent assay demonstrated the nuclear translocation decrease of NF-κB in LLL treated LPS induced MSCs. Western blot analysis also suggested that LLL suppressed NF-κB activation via regulating the phosphorylation of p65 and IκBα. MSC significantly reduced the expression of activation markers CD25 and CD69 on PHA-stimulated lymphocytes.

Conclusion

The results indicate that LLL suppressed the activation of NF-κB signaling pathway in LPS treated MSCs through inhibiting phosphorylation of p65 and IκBα, which results in good anti-inflammatory effect. In addition, LLL attenuated activation-associated markers CD25 and CD69 in co-cultures of PBMC and 3 types of treated MSCs.

Regenerative Medicine: lessons from Mother Nature

Regenerative medicine strategies for the restoration of functional tissue have evolved from the concept of ex vivo creation of engineered tissue toward the broader concept of in vivo induction of functional tissue reconstruction. Multidisciplinary approaches are being investigated to achieve this goal using evolutionarily conserved principles of stem cell biology, developmental biology and immunology, current methods of engineering and medicine. This evolution from ex vivo tissue engineering to the manipulation of fundamental in vivo tenets of development and regeneration has the potential to capitalize upon the incredibly complex and only partially understood ability of cells to adapt, proliferate, self-organize and differentiate into functional tissue.

Interactions between MSCs and immune cells: implications for bone healing

It is estimated that, of the 7.9 million fractures sustained in the United States each year, 5% to 20% result in delayed or impaired healing requiring therapeutic intervention. Following fracture injury, there is an initial inflammatory response that plays a crucial role in bone healing; however, prolonged inflammation is inhibitory for fracture repair. The precise spatial and temporal impact of immune cells and their cytokines on fracture healing remains obscure. Some cytokines are reported to be proosteogenic while others inhibit bone healing. Cell-based therapy utilizing mesenchymal stromal cells (MSCs) is an attractive option for augmenting the fracture repair process. Osteoprogenitor MSCs not only differentiate into bone, but they also exert modulatory effects on immune cells via a variety of mechanisms. In this paper, we review the current literature on both in vitro and in vivo studies on the role of the immune system in fracture repair, the use of MSCs in the enhancement of fracture healing, and interactions between MSCs and immune cells. Insight into this paradigm can provide valuable clues in identifying cellular and noncellular targets that can potentially be modulated to enhance both natural bone healing and bone repair augmented by the exogenous addition of MSCs.

MSC therapy attenuates obliterative bronchiolitis after murine bone marrow transplant

RATIONALE

Obliterative bronchiolitis (OB) is a significant cause of morbidity and mortality after lung transplant and hematopoietic cell transplant. Mesenchymal stromal cells (MSCs) have been shown to possess immunomodulatory properties in chronic inflammatory disease.

OBJECTIVE

Administration of MSCs was evaluated for the ability to ameliorate OB in mice using our established allogeneic bone marrow transplant (BMT) model.

METHODS

Mice were lethally conditioned and received allogeneic bone marrow without (BM) or with spleen cells (BMS), as a source of OB-causing T-cells. Cell therapy was started at 2 weeks post-transplant, or delayed to 4 weeks when mice developed airway injury, defined as increased airway resistance measured by pulmonary function test (PFT). BM-derived MSC or control cells [mouse pulmonary vein endothelial cells (PVECs) or lung fibroblasts (LFs)] were administered. Route of administration [intratracheally (IT) and IV] and frequency (every 1, 2 or 3 weeks) were compared. Mice were evaluated at 3 months post-BMT.

MEASUREMENTS AND MAIN RESULTS

No ectopic tissue formation was identified in any mice. When compared to BMS mice receiving control cells or no cells, those receiving MSCs showed improved resistance, compliance and inspiratory capacity. Interim PFT analysis showed no difference in route of administration. Improvements in PFTs were found regardless of dose frequency; but once per week worked best even when administration began late. Mice given MSC also had decreased peribronchiolar inflammation, lower levels of hydroxyproline (collagen) and higher frequencies of macrophages staining for the alternatively activated macrophage (AAM) marker CD206.

CONCLUSIONS

These results warrant study of MSCs as a potential management option for OB in lung transplant and BMT recipients.

Unique characteristics of human mesenchymal stromal/progenitor cells pre-activated in 3-dimensional cultures under different conditions

BACKGROUND AIMS

Human mesenchymal stromal cells (MSCs) are being used in clinical trials, but the best protocol to prepare the cells for administration to patients remains unclear. We previously demonstrated that MSCs could be pre-activated to express therapeutic factors by culturing the cells in 3 dimensions (3D). We compared the activation of MSCs in 3D in fetal bovine serum containing medium and in multiple xeno-free media formulations.

METHODS

MSC aggregation and sphere formation was studied with the use of hanging drop cultures with medium containing fetal bovine serum or with various commercially available stem cell media with or without human serum albumin (HSA). Activation of MSCs was studied with the use of gene expression and protein secretion measurements and with functional studies with the use of macrophages and cancer cells.

RESULTS

MSCs did not condense into tight spheroids and express a full complement of therapeutic genes in α-minimum essential medium or several commercial stem-cell media. However, we identified a chemically defined xeno-free media, which, when supplemented with HSA from blood or recombinant HSA, resulted in compact spheres with high cell viability, together with high expression of anti-inflammatory (prostaglandin E2, TSG-6 TNF-alpha induced gene/protein 6) and anti-cancer molecules (TRAIL TNF-related apoptosis-inducing ligand, interleukin-24). Furthermore, spheres cultured in this medium showed potent anti-inflammatory effects in a lipopolysaccharide-stimulated macrophage system and suppressed the growth of prostate cancer cells by promoting cell-cycle arrest and cell death.

CONCLUSIONS

We demonstrated that cell activation in 3D depends critically on the culture medium. The conditions developed in the present study for 3D culture of MSCs should be useful in further research on MSCs and their potential therapeutic applications.