A procedure for in vitro evaluation of the immunosuppressive effect of mouse mesenchymal stem cells on activated T cell proliferation

Immunomodulatory function of licensed human bone marrow mesenchymal stromal cell-derived apoptotic bodies

BACKGROUND

Mesenchymal stromal cells (MSCs) show great potential for immunomodulatory and anti-inflammatory treatments. Clinical trials have been performed for the treatment of Type 1 diabetes, graft-versus-host disease and organ transplantation, which offer a promise of MSCs as an immunomodulatory therapy. Nevertheless, their unstable efficacy and immunogenicity concerns present challenges to clinical translation. It has emerged that the MSC-derived secretome, which includes secreted proteins, exosomes, apoptotic bodies (ABs) and other macromolecules, may have similar therapeutic effects to parent MSCs. Among all of the components of the MSC-derived secretome, most interest thus far has been garnered by exosomes for their therapeutic potential. However, since MSCs were reported to undergo apoptosis after in vivo transplantation and release ABs, we speculated as to whether ABs have immunomodulatory effects. In this study, cytokine licensing was used to enhance the immunomodulatory potency of MSCs and ABs derived from licensed MSCs in vitro were isolated to explore their immunomodulatory effects as an effective non-viable cell therapy.

RESULTS

IFN-γ and IFN-γ/TGF-β1 licensing enhanced the immunomodulatory effect of MSCs on T cell proliferation. Further, TGF-β1 and IFN-γ licensing strengthened the immunomodulatory effect of MSC on reducing the TNF-α and IL-1β expression by M1 macrophage-like THP-1 cells. Additionally, we discovered the immunomodulatory effect mediated by MSC-derived apoptotic bodies. Licensing impacted the uptake of ABs by recipient immune cells and importantly altered their phenotypes.

CONCLUSION

ABs derived from IFN-γ/TGF-β1-licensed apoptotic MSCs significantly inhibited T cell proliferation, induced more regulatory T cells, and maintained immunomodulatory T cells but reduced pro-inflammatory T cells.

Immune homeostasis modulation by hydrogel-guided delivery systems: a tool for accelerated bone regeneration

Immune homeostasis is delicately mediated by the dynamic balance between effector immune cells and regulatory immune cells. Local deviations from immune homeostasis in the microenvironment of bone fractures, caused by an increased ratio of effector to regulatory cues, can lead to excessive inflammatory conditions and hinder bone regeneration. Therefore, achieving effective and localized immunomodulation of bone fractures is crucial for successful bone regeneration. Recent research has focused on developing localized and specific immunomodulatory strategies using local hydrogel-based delivery systems. In this review, we aim to emphasize the significant role of immune homeostasis in bone regeneration, explore local hydrogel-based delivery systems, discuss emerging trends in immunomodulation for enhancing bone regeneration, and address the limitations of current delivery strategies along with the challenges of clinical translation.

Shining the light on mesenchymal stem cell-derived exosomes in breast cancer

In women, breast cancer (BC) is the second most frequently diagnosed cancer and the leading cause of cancer death. Mesenchymal stem cells (MSCs) are a subgroup of heterogeneous non-hematopoietic fibroblast-like cells that have the ability to differentiate into multiple cell types. Recent studies stated that MSCs can migrate into the tumor sites and exert various effect on tumor growth and development. Multiple researches have demonstrated that MSCs can favor tumor growth, while other groups have indicated that MSCs inhibit tumor development. Emerging evidences showed exosomes (Exo) as a new mechanism of cell communication which are essential for the crosstalk between MSCs and BC cells. MSC-derived Exo (MSCs-Exo) could mimic the numerous effects on the proliferation, metastasis, and drug response through carrying a wide scale of molecules, such as proteins, lipids, messenger RNAs, and microRNAs to BC cells. Consequently, in the present literature, we summarized the biogenesis and cargo of Exo and reviewed the role of MSCs-Exo in development of BC.

Personalized medicine in rheumatoid arthritis: Combining biomarkers and patient preferences to guide therapeutic decisions

The last few decades have seen major therapeutic advancements in rheumatoid arthritis (RA) therapeutics. New disease-modifying antirheumatic drugs (DMARDs) have continued to emerge, creating more choices for people. However, no therapeutic works for all patients. Each has its own inherent benefits, risks, costs, dosing, and monitoring considerations. In parallel, there has been a focus on personalized medicine initiatives that tailor therapeutic decisions to patients based on their unique characteristics or biomarkers. Personalized effect estimates require an understanding of a patient's baseline probability of response to treatment and data on the comparative effectiveness of the available treatments. However, even if accurate risk prediction models are available, trade-offs often still need to be made between treatments. In this paper, we review the history of RA therapeutics and progress that has been made toward personalized risk predictive models for DMARDs, outlining where knowledge gaps still exist. We further review why patient preferences play a key role in a holistic view of personalized medicine and how this links with shared decision-making. We argue that a "preference misdiagnosis" may be equally important as a medical misdiagnosis but is often overlooked.

Clinical application of mesenchymal stem cell in regenerative medicine: a narrative review

The multipotency property of mesenchymal stem cells (MSCs) has attained worldwide consideration because of their immense potential for immunomodulation and their therapeutic function in tissue regeneration. MSCs can migrate to tissue injury areas to contribute to immune modulation, secrete anti-inflammatory cytokines and hide themselves from the immune system. Certainly, various investigations have revealed anti-inflammatory, anti-aging, reconstruction, and wound healing potentials of MSCs in many in vitro and in vivo models. Moreover, current progresses in the field of MSCs biology have facilitated the progress of particular guidelines and quality control approaches, which eventually lead to clinical application of MSCs. In this literature, we provided a brief overview of immunoregulatory characteristics and immunosuppressive activities of MSCs. In addition, we discussed the enhancement, utilization, and therapeutic responses of MSCs in neural, liver, kidney, bone, heart diseases, and wound healing.

Injectable Hyaluronic Acid/Human Umbilical Cord Mesenchymal Stem Cells/Bone Morphogenetic Protein-2 Promotes the Repair of Radial Bone Defects in Rabbits

Background: Bone defects are common in orthopedics and can be caused by congenital diseases, trauma, infection, tumors and other reasons. The treatment of large-scale bone defects is a clinical problem faced by orthopedists. The development of tissue engineering technology is expected to solve this problem. Objective: To explore the effect of injectable hyaluronic acid/hUCMSC/BMP-2 on the healing of rabbit radial bone defects. Methods: X-ray examination and tissue specimens were examined to macroscopically observe bone defect healing; tetracycline fluorescence and vonKossa staining were performed to observe the formation of new bone, and H&E staining was performed to examine cartilage and trabecular bone formation. Results: The injectable hyaluronic acid/hUCMSC/BMP-2 could significantly promote the early repair of bone defects and accelerate the process of bone formation. Conclusion: The direct injection of hyaluronic acid/hUCMSC/BMP-2 into afresh bone defect site has a significant beneficial effect on early repair of the bone defect.

Mesenchymal Stem Cell-Based Therapy for Rheumatoid Arthritis

Mesenchymal stem cells (MSCs) have great potential to differentiate into various types of cells, including but not limited to, adipocytes, chondrocytes and osteoblasts. In addition to their progenitor characteristics, MSCs hold unique immunomodulatory properties that provide new opportunities in the treatment of autoimmune diseases, and can serve as a promising tool in stem cell-based therapy. Rheumatoid arthritis (RA) is a chronic systemic autoimmune disorder that deteriorates quality and function of the synovium membrane, resulting in chronic inflammation, pain and progressive cartilage and bone destruction. The mechanism of RA pathogenesis is associated with dysregulation of innate and adaptive immunity. Current conventional treatments by steroid drugs, antirheumatic drugs and biological agents are being applied in clinical practice. However, long-term use of these drugs causes side effects, and some RA patients may acquire resistance to these drugs. In this regard, recently investigated MSC-based therapy is considered as a promising approach in RA treatment. In this study, we review conventional and modern treatment approaches, such as MSC-based therapy through the understanding of the link between MSCs and the innate and adaptive immune systems. Moreover, we discuss recent achievements in preclinical and clinical studies as well as various strategies for the enhancement of MSC immunoregulatory properties.

Identification of a Hematopoietic Cell Population Emerging From Mouse Bone Marrow With Proliferative Potential In Vitro and Immunomodulatory Capacity

There is continuing interest in therapeutic applications of bone marrow-derived mesenchymal stromal cells (MSC). Unlike human counterparts, mouse MSC are difficult to propagate in vitro due to their contamination with adherent hematopoietic cells that overgrow the cultures. Here we investigated the properties of these contaminating cells, referred to as bone marrow-derived proliferating hematopoietic cells (BM-PHC). The results showed that both BM-PHC and MSC had strong immunomodulatory properties on T cells in vitro, with PGE2 and NO involved in this mechanism. However, BM-PHC were stronger immunomodulators than MSC, with CCL-6 identified as putative molecule responsible for superior effects. In vivo studies showed that, in contrast to BM-PHC, MSC endorsed a more rapid xenograft tumor rejection, thus indicating a particular context in which only MSC therapy would produce positive outcomes. In conclusion, bone marrow contains two cell populations with immunomodulatory properties, which are valuable sources for therapeutic studies in specific disease-relevant contexts.

Mesenchymal Stem Cells Can Both Enhance and Inhibit the Cellular Response to DNA Immunization by Genes of Nonstructural Proteins of the Hepatitis C Virus

Despite extensive research, there is still no vaccine against the hepatitis C virus (HCV). The aim of this study was to investigate whether MSCs can exhibit adjuvant properties during DNA vaccination against hepatitis C. We used the pcNS3-NS5B plasmid encoding five nonstructural HCV proteins and MSCs derived from mice bone marrow. Five groups of DBA mice were immunized with the plasmid and/or MSCs in a different order. Group 1 was injected with the plasmid twice at intervals of 3 weeks; Group 2 with the plasmid, and after 24 h with MSCs; Group 3 with MSCs followed by the plasmid the next day; Group 4 with only MSCs; and Group 5 with saline. When the MSCs were injected prior to DNA immunization, the cell immune response to HCV proteins assessed by the level of IFN-γ synthesis was markedly increased compared to DNA alone. In contrast, MSCs injected after DNA suppressed the immune response. Apparently, the high level of proinflammatory cytokines detected after DNA injection promotes the conversion of MSCs introduced later into the immunosuppressive MSC2. The low level of cytokines in mice before MSC administration promotes the high immunostimulatory activity of MSC1 in response to a DNA vaccine. Thus, when administered before DNA, MSCs are capable of exhibiting promising adjuvant properties.

Mesenchymal Stem Cells Can Both Enhance and Inhibit the Cellular Response to DNA Immunization by Genes of Nonstructural Proteins of the Hepatitis C Virus

Despite extensive research, there is still no vaccine against the hepatitis C virus (HCV). The aim of this study was to investigate whether MSCs can exhibit adjuvant properties during DNA vaccination against hepatitis C. We used the pcNS3-NS5B plasmid encoding five nonstructural HCV proteins and MSCs derived from mice bone marrow. Five groups of DBA mice were immunized with the plasmid and/or MSCs in a different order. Group 1 was injected with the plasmid twice at intervals of 3 weeks; Group 2 with the plasmid, and after 24 h with MSCs; Group 3 with MSCs followed by the plasmid the next day; Group 4 with only MSCs; and Group 5 with saline. When the MSCs were injected prior to DNA immunization, the cell immune response to HCV proteins assessed by the level of IFN-γ synthesis was markedly increased compared to DNA alone. In contrast, MSCs injected after DNA suppressed the immune response. Apparently, the high level of proinflammatory cytokines detected after DNA injection promotes the conversion of MSCs introduced later into the immunosuppressive MSC2. The low level of cytokines in mice before MSC administration promotes the high immunostimulatory activity of MSC1 in response to a DNA vaccine. Thus, when administered before DNA, MSCs are capable of exhibiting promising adjuvant properties.

Mesenchymal Stem Cells Can Both Enhance and Inhibit the Cellular Response to DNA Immunization by Genes of Nonstructural Proteins of the Hepatitis C Virus

Despite extensive research, there is still no vaccine against the hepatitis C virus (HCV). The aim of this study was to investigate whether MSCs can exhibit adjuvant properties during DNA vaccination against hepatitis C. We used the pcNS3-NS5B plasmid encoding five nonstructural HCV proteins and MSCs derived from mice bone marrow. Five groups of DBA mice were immunized with the plasmid and/or MSCs in a different order. Group 1 was injected with the plasmid twice at intervals of 3 weeks; Group 2 with the plasmid, and after 24 h with MSCs; Group 3 with MSCs followed by the plasmid the next day; Group 4 with only MSCs; and Group 5 with saline. When the MSCs were injected prior to DNA immunization, the cell immune response to HCV proteins assessed by the level of IFN-γ synthesis was markedly increased compared to DNA alone. In contrast, MSCs injected after DNA suppressed the immune response. Apparently, the high level of proinflammatory cytokines detected after DNA injection promotes the conversion of MSCs introduced later into the immunosuppressive MSC2. The low level of cytokines in mice before MSC administration promotes the high immunostimulatory activity of MSC1 in response to a DNA vaccine. Thus, when administered before DNA, MSCs are capable of exhibiting promising adjuvant properties.

Immunopathology of Type 1 Diabetes and Immunomodulatory Effects of Stem Cells: A Narrative Review of the Literature

Type 1 Diabetes (T1D) is a complex autoimmune disorder which occurs as a result of an intricate series of pathologic interactions between pancreatic β-cells and a wide range of components of both the innate and the adaptive immune systems. Stem-cell therapy, a recently-emerged potentially therapeutic option for curative treatment of diabetes, is demonstrated to cause significant alternations to both different immune cells such as macrophages, natural killer (NK) cells, dendritic cells, T cells, and B cells and non-cellular elements including serum cytokines and different components of the complement system. Although there exists overwhelming evidence indicating that the documented therapeutic effects of stem cells on patients with T1D is primarily due to their potential for immune regulation rather than pancreatic tissue regeneration, to date, the precise underlying mechanisms remain obscure. On the other hand, immune-mediated rejection of stem cells remains one of the main obstacles to regenerative medicine. Moreover, the consequences of efferocytosis of stem-cells by the recipients' lung-resident macrophages have recently emerged as a responsible mechanism for some immune-mediated therapeutic effects of stem-cells. This review focuses on the nature of the interactions amongst different compartments of the immune systems which are involved in the pathogenesis of T1D and provides explanation as to how stem cell-based interventions can influence immune system and maintain the physiologic equilibrium.