Mesenchymal stem cell transplantation inhibits abnormal activation of Akt/GSK3β signaling pathway in T cells from systemic lupus erythematosus mice

Modulation of Mesenchymal Stem Cells-Mediated Adaptive Immune Effectors' Repertoire in the Recovery of Systemic Lupus Erythematosus

The breakdown of self-tolerance of the immune response can lead to autoimmune conditions in which chronic inflammation induces tissue damage. Systemic lupus erythematosus (SLE) is a debilitating multisystemic autoimmune disorder with a high prevalence in women of childbearing age; however, SLE incidence, prevalence, and severity are strongly influenced by ethnicity. Although the mystery of autoimmune diseases remains unsolved, disturbance in the proportion and function of B cell subsets has a major role in SLE's pathogenesis. Additionally, colocalizing hyperactive T helper cell subgroups within inflammatory niches are indispensable. Despite significant advances in standard treatments, nonspecific immunosuppression, the risk of serious infections, and resistance to conventional therapies in some cases have raised the urgent need for new treatment strategies. Without the need to suppress the immune system, mesenchymal stem cells (MSCs), as ''smart" immune modulators, are able to control cellular and humoral auto-aggression responses by participating in precursor cell development. In lupus, due to autologous MSCs disorder, the ability of allogenic engrafted MSCs in tissue regeneration and resetting immune homeostasis with the provision of a new immunocyte repertoire has been considered simultaneously. In Brief The bone marrow mesenchymal stem cells (BM-MSCs) lineage plays a critical role in maintaining the hematopoietic stem-cell microstructure and modulating immunocytes. The impairment of BM-MSCs and their niche partially contribute to the pathogenesis of SLE-like diseases. Allogenic MSC transplantation can reconstruct BM microstructure, possibly contributing to the recovery of immunocyte phenotype restoration of immune homeostasis. In terms of future prospects of MSCs, artificially gained by ex vivo isolation and culture adaptation, the wide variety of potential mediators and mechanisms might be linked to the promotion of the immunomodulatory function of MSCs.

Evaluation of the Therapeutic Potential of Mesenchymal Stem Cells (MSCs) in Preclinical Models of Autoimmune Diseases

Autoimmune diseases, chronic in nature, are generally hard to alleviate. Present long-term treatments with available drugs such as steroids, immune-suppressive drugs, or antibodies have several debilitating side effects. Therefore, new treatment options are urgently needed. Stem cells, in general, have the potential to reduce immune-mediated damage through immunomodulation and T cell regulation (T regs) by inhibiting the proliferation of dendritic cells and T and B cells and reducing inflammation through the generation of immunosuppressive biomolecules like interleukin 10 (IL-10), transforming growth factor-β (TGF-β), nitric oxide (NO), indoleamine 2,3-dioxygenase (IDO), and prostaglandin E2 (PGE2). Many stem cell-based therapeutics have been evaluated in the clinic, but the overall clinical outcomes in terms of efficacy and the longevity of therapeutic benefits seem to be variable and inconsistent with the postulated benefits. This emphasizes a greater need for building robust preclinical models and models that can better predict the clinical translation of stem cell-based therapeutics. Stem cell therapy based on MSCs having the definitive potential to regulate the immune system and control inflammation is emerging as a promising tool for the treatment of autoimmune disorders while promoting tissue regeneration. MSCs, derived from bone marrow, umbilical cord, and adipose tissue, have been shown to be highly immunomodulatory and anti-inflammatory and shown to enhance tissue repair and regeneration in preclinical models as well as in clinical settings. In this article, a review on the status of MSC-based preclinical disease models with emphasis on understanding disease mechanisms in chronic inflammatory disorders caused by exaggerated host immune response in rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) was carried out. We also emphasized various factors that better predict the translation of stem cell therapeutic outcomes from preclinical disease models to human patients.

Association between Mesenchymal Stem Cells and COVID-19 Therapy: Systematic Review and Current Trends

Background

The novel coronavirus first emerged in Wuhan, China, and quickly spread across the globe, spanning various countries and resulting in a worldwide pandemic by the end of December 2019. Given the current advances in treatments available for COVID-19, mesenchymal stem cell (MSC) therapy seems to be a prospective option for management of ARDS observed in COVID-19 patients. This present study is aimed at exploring the therapeutic potential and safety of using MSC obtained by isolation from health cord tissues in the treatment of patients with COVID-19.

Methods

A systematic search was done based on the guidelines of the PRISMA 2020 statement. A literature search was executed using controlled vocabulary and indexing of trials to evaluate all the relevant studies involving the use of medical subject headings (MeSH) in electronic databases like PubMed, Embase, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), and clinicaltrials.gov up to 31 December 2021. The protocol was registered in the PROSPERO register with ID CRD42022301666. Findings. After screening finally, 22 remaining articles were included in this systematic review. The studies revealed that MSC exosomes are found to be superior to MSC alone in terms of safety owing to being smaller with a lesser immunological response which leads to free movement in blood capillaries without clumping and also cannot further divide, thus reducing the oncogenic potential of MSC-derived exosomes as compared to MSC only. The studies demonstrated that the lungs healed with the use of exosomes compared to how they presented initially at the hospital. MSCs are found to increase the angiogenesis process and alveolar reepithelization, reducing markers like TNF alpha, TGF beta, and COL I and III, reducing the growth of myofibroblasts and increasing survivability of endothelium leading to attenuated pulmonary fibrosis and even reversing them. Interpretation. We can conclude that the use of mesenchymal stem cells or their derived exosomes is safe and well-tolerated in patients with COVID-19. It improves different parameters of oxygenation and helps in the healing of the lungs. The viral load along with different inflammatory cells and biomarkers of inflammation tend to decrease. Chest X-ray, CT scan, and different radiological tools are used to show improvement and reduced ongoing destructive processes.

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

Background

Mesenchymal stem/stromal cells (MSC) represent adult cells with multipotent capacity. Besides their capacity to differentiate into multiple lineages in vitro and in vivo, increasing evidence points towards the immunomodulatory capacity of these cells, as an important feature for their therapeutic power. Although not included in the minimal criteria established by the International Society for Cellular Therapy as a defining MSC attribute, demonstration of the immunomodulatory capacity of MSC can be useful for the characterization of these cells before being considered MSC.

Methods

Here we present a simple and reliable protocol by which the immunosuppressive effect of mouse bone marrow-derived MSC can be evaluated in vitro. It is based on the measuring of the proliferation of activated T cells cultured in direct contact with irradiated MSC.

Results

Our results showed that mouse MSC have a dose-dependent inhibitory effect on activated T cell proliferation, which can be quantified as a percentage of maximum proliferation. Our data shows that batch-to-batch variability can be determined within one or multiple experiments, by extracting the area under curve of T cell proliferation plotted against the absolute number of MSC in co-culture.

Conclusions

The validation of the immunosupressive capacity of MSC could be added to the characterization of the cells before being used in various MSC-based approaches to treat immunological diseases. Our results showed that mouse MSC have a dose-dependent inhibitory effect on activated T cell proliferation. The immunosuppressive properties of MSC vary between batches, but not between different passages of the same batch.

An Update for Mesenchymal Stem Cell Therapy in Lupus Nephritis

Background

Lupus nephritis (LN) is the most severe organ manifestations of systemic lupus erythematosus (SLE). Although increased knowledge of the disease pathogenesis has improved treatment options, outcomes have plateaued as current immunosuppressive therapies have failed to prevent disease relapse in more than half of treated patients. Thus, there is still an urgent need for novel therapy. Mesenchymal stem cells (MSCs) possess a potently immunosuppressive regulation on immune responses, and intravenous transplantation of MSCs ameliorates disease symptoms and has emerged as a potential beneficial therapy for LN. The objective of this review is to discuss the defective functions of MSCs in LN patients and the application of MSCs in the treatment of both LN animal models and patients.

Summary

Bone marrow MSCs from SLE patients exhibit impaired capabilities of migration, differentiation, and immune regulation and display senescent phenotype. Allogeneic MSCs suppress autoimmunity and restore renal function in mouse models and patients with LN by inducing regulatory immune cells and suppressing Th1, Th17, T follicular helper cell, and B-cell responses. In addition, MSCs can home to the kidney and integrate into tubular cells and differentiate into mesangial cells.

Key Messages

The efficacy of MSCs in the LN treatment remains to be confirmed, and future advances from stem cell science can be expected to pinpoint significant MSC subpopulations, as well as specific mechanisms of action, leading the way to the use of more potent stimulated or primed pretreated MSCs to treat LN.

Human umbilical cord-derived mesenchymal stem cell therapy ameliorates lupus through increasing CD4+ T cell senescence via MiR-199a-5p/Sirt1/p53 axis

Rationale: Although human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) transplantation has been proved to be an effective therapeutic approach to treat systemic lupus erythematosus (SLE), the detailed underlying mechanisms are not fully understood. Transferring miRNAs is one mean by which MSCs communicate with surrounding cells. Sirt1 is a NAD-dependent deacetylase that protects against cell senescence by deacetylating p53. Here we aimed to explore whether hUC-MSCs affected senescence of splenic CD4+ T cells through regulating Sirt1/p53 via miRNA in the MRL/lpr lupus mouse model.

Methods: The effects of hUC-MSCs on lupus syndrome and senescence pathways in MRL/lpr mice in vivo and in vitro were determined. The functional roles of miR-199a-5p in splenic CD4+ T cell senescence were studied by miRNA mimic or inhibitor in vitro. MRL/lpr mice were injected with miR-199a-5p agomir to evaluate the effects of miR-199a-5p on splenic CD4+ T cell senescence and disease in vivo.

Results: We showed that hUC-MSCs transplantation ameliorated lupus symptoms and increased senescence of splenic CD4+ T cells through Sirt1/p53 signaling via miR-199a-5p in MRL/lpr mice. Moreover, systemic delivery of miR-199a-5p in MRL/lpr mice increased splenic CD4+ T-cell senescence, mimicking the therapeutic effects of transplanted hUC-MSCs.

Conclusions: We have identified miR-199a-5p as one of the mechanisms employed by hUC-MSCs to alleviate lupus disease associated pathologies in MRL/lpr mice, which is attributable for promoting splenic CD4+ T cell senescence through Sirt1/p53 pathway.

An Overview of the Safety, Efficiency, and Signal Pathways of Stem Cell Therapy for Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that affects multiple organs and tissues. Mesenchymal stem cells (MSCs) are considered a good source for autoimmune disease and hematological disease therapy. This review will summarize the efficacy, safety, and mechanisms of MSC therapy for SLE. MSC therapy can reduce anti-dsDNA, antinuclear antigen (ANA), proteinuria, and serum creatinine in SLE patients. In animal models of SLE, MSC therapy also indicates that it could reduce anti-dsDNA, ANA, proteinuria, and serum creatinine and ameliorate renal pathology. There are no serious adverse events, treatment-related mortality, or tumor-related events in SLE patients after stem cell treatment. MSCs can inhibit inflammatory factors, such as MCP-1 and HMGB-1, and inhibit inflammation-related signaling pathways, such as the NF-κB, JAK/STAT, and Akt/GSK3β signaling pathways, to alleviate the lesions in SLE.

The immunomodulatory effects of mesenchymal stromal cell-based therapy in human and animal models of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic systemic autoimmune inflammatory disease with no absolute cure. Although the exact etiopathogenesis of SLE is still enigmatic, it has been well demonstrated that a combination of genetic predisposition and environmental factors trigger a disturbance in immune responses and thereby participate in the development of this condition. Almost all available therapeutic strategies in SLE are primarily based on the administration of immunosuppressive drugs and are not curative. Mesenchymal stromal cells (MSCs) are a subset of non-hematopoietic adult stem cells that can be isolated from many adult tissues and are increasingly recognized as immune response modulating agents. MSC-mediated inhibition of immune responses is a complex mechanism that involves almost every aspect of the immune response. MSCs suppress the maturation of antigen-presenting cells (DC and MQ), proliferation of T cells (Th1, T17, and Th2), proliferation and immunoglobulin production of B cells, the cytotoxic activity of CTL and NK cells in addition to increasing regulatory cytokines (TGF-β and IL10), and decreasing inflammatory cytokines (IL17, INF-ϒ, TNF-α, and IL12) levels. MSCs have shown encouraging results in the treatment of several autoimmune diseases, in particular SLE. This report aims to review the beneficial and therapeutic properties of MSCs; it also focuses on the results of animal model studies, preclinical studies, and clinical trials of MSC therapy in SLE from the immunoregulatory aspect.

The multi-targets mechanism of hydroxychloroquine in the treatment of systemic lupus erythematosus based on network pharmacology

BACKGROUND

Network pharmacology is used with bioinformatic tools to broaden the understanding of drugs' potential targets and the intersections with key genes of particular disease. Here we applied network pharmacology to collect testable hypotheses about the multi-targets mechanism of hydroxychloroquine (HCQ) against systemic lupus erythematosus (SLE).

METHODS

Firstly, we predicted the potential targets of HCQ. Secondly, we got the related genes of SLE returned from databases. Thirdly, the intersections of the potential targets (HCQ) and related genes (SLE) were analyzed with gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. Finally, we validated our predictions of the potential targets by performing docking studies with HCQ.

RESULTS

The results suggest that the efficacy of HCQ against SLE is mainly associated with the targets of cyclin-dependent kinase 2 (CDK2), estrogen receptor alpha (ESR1) and CDK1, which regulate PI3K/Akt/GSK3β as well as interferon (IFN) signaling pathway. Biological process of the network associated with the three targets is concentrated in the inhibition of immune response, negative regulation of gene expression and regulation of immune system process. Molecular docking analysis proves that hydrogen bonding and π-π stacking are the main forms of interaction.

CONCLUSIONS

Our research provides protein targets affected by HCQ in the treatment of SLE. Three key targets (CDK2, ESR1 and CDK1) involving 1766 proteins become the multi-targets mechanism of HCQ in the treatment of SLE. As well, the research also provides a new idea for introducing network pharmacology into the evaluation of the drugs with multi-targets in dermatology.

MCP-1 Priming Enhanced the Therapeutic Effects of Human Mesenchymal Stromal Cells on Contact Hypersensitivity Mice by Activating the COX2-PGE2/STAT3 Pathway

Mesenchymal stromal cells (MSCs) have become a promising treatment for inflammation-related diseases, and their therapeutic efficacy mainly depends on crosstalk between MSCs and inflammation. However, methods to improve the immunosuppressive efficiency of MSCs in different diseases still need to be developed. In this study, we investigated whether preconditioning MSCs with a disease-related inflammatory cytokine could increase their immunosuppressive properties and improve therapeutic efficacy. In a contact hypersensitivity (CHS) mouse model, inflammatory profile screening revealed that among all tested cytokines, monocyte chemotactic protein-1 (MCP-1) exhibited the most significantly increased level in the local microenvironment. As expected, MSCs preconditioned with MCP-1 (P-MSCs) exhibited an enhanced ability to downregulate proinflammatory cytokine secretion, induce regulatory T cells, inhibit T cell proliferation, and polarize M2-type macrophages. In vivo experiments showed that P-MSCs alleviated ear swelling and local proinflammatory cytokine production more effectively than control MSCs. Mechanistically, MCP-1 could significantly activate the signal transducer and activator of transcription 3 (STAT3) signaling pathway and induce the expression of cyclooxygenase-2 (COX2) and prostaglandin E2 (PGE2) in MSCs. STAT3 inhibitor reversed the MCP-1-mediated enhancing of their immunosuppressive ability. Collectively, our findings demonstrate that CHS-related MCP-1 preconditioning enhanced the immunomodulatory effects of MSCs and improved their therapeutic efficacy in CHS. Enhancing the immunosuppressive efficacy of MSCs by preconditioning with certain disease-related inflammatory cytokines may provide a new strategy for MSC-based therapies for inflammatory diseases.

Efficacy of mesenchymal stem cells in animal models of lupus nephritis: a meta-analysis

BACKGROUND

Lupus nephritis is usually manifested by proteinuria, active urinary sediment, hypertension, and renal failure and is a serious complication with more than 50% occurrence in systemic lupus erythematosus patients. Mesenchymal stem cells (MSC) present remarkable immunomodulatory ability, and these cells are potential therapeutic agents for autoimmune disorders. In clinical trials, the effectiveness of MSC in the treatment of lupus nephritis is still controversial. A meta-analysis was performed to assess whether MSC can achieve good efficacy in the treatment of lupus nephritis in mice.

METHODS

A comprehensive literature search was performed in Cochrane Library, ISI Web of Science, PubMed, and EMBASE from inception to Oct 1, 2019. Two authors independently extracted the data, which were pooled and calculated using RevMan 5.3.

RESULTS

A total of 28 studies met the inclusion criteria. MSC treatment resulted in lower levels of ds-DNA (OR = - 29.58, 95% CI - 29.58, - 17.99; P < 0.00001), ANA (OR = - 70.93, 95% CI - 104.55, - 37.32; P < 0.0001), Scr (OR = - 8.20, 95% CI - 12.71, - 3.69; P = 0.0004), BUN (OR = - 14.57, 95% CI - 20.50, - 8.64; P < 0.00001), proteinuria (OR = - 4.26, 95% CI - 5.15 to - 3.37; P < 0.00001), and renal sclerosis score (OR = - 1.92, 95% CI - 2.66 to - 1.18; P < 0.00001), and MSC treatment could get higher levels of albumin. To detect the potential, the cytokines were also assessed, and the MSC treatment group had lower levels of IL-2, IL-12, IL-17, and IFN-γ when compared with the control group. However, the difference was not notable for IL-4, IL-6, IL-10, TGF-β, MCP-1, TNF-α, Th1, Th17, Foxp3, or Tregs.

CONCLUSION

Our study confirmed that MSC treatment in an animal model for lupus nephritis in the studies included in the meta-analysis resulted in lower levels of ds-DNA, ANA, Scr, BUN, proteinuria, and renal sclerosis score, and MSC treatment could get higher levels of albumin.

Therapeutic applications of adipose-derived mesenchymal stem cells on acute liver injury in canines

In this study, canine adipose-derived mesenchymal stem cells (cADSCs) therapeutic potential was investigated in artificially induced acute liver injury model by CCl₄ in canines. The primary cADSCs cells were cultured and then intravenously administered into the canine animal model. Six cross-breed dogs were divided into three groups including blank control group, CCl₄ model group, CCl₄ induced cADSCs transplantation group. The results showed that after intraperitoneal injection of CCl₄ solution, the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and Albumin (ALB) in peripheral blood of experimental canines confirmed the correct induction of acute liver injury. Moreover, the liver structure showed clear macroscopic damage. The cADSCs were homed in the liver of the administered animals. The AST, ALT and ALB in the peripheral blood rapidly decreased. H&E and PAS histological evaluation showed that both the structure of canine liver tissue and the ability to synthesize hepatic glycogen could be restored to the control level after cADSCs transplantation. Therefore, cADSCs can play a therapeutic role in the recovery of liver injury. Overall, this study demonstrates that the primary cADSCs transplantation into the acute liver injury model induced by intravenous injection can play a certain therapeutic role in the recovery of liver in canines. These results may provide a new treatment idea for acute liver disease in pets clinically.

Stem cells for lupus nephritis: a concise review of current knowledge

Lupus nephritis (LN), a common manifestation of systemic lupus erythematosus (SLE), accounts for significant morbidity and mortality in SLE patients. Since the available standard therapies and biologic agents for LN are yet to achieve the desired response and have considerable secondary effects, stem cell therapy has now emerged as a new approach. This therapy involves the transplantation of hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs). Our current review will highlight the progress of stem cell therapy for LN, along with the challenges encountered and the future direction of this approach.

Treatment with Allogenic Mesenchymal Stromal Cells in a Murine Model of Systemic Lupus Erythematosus

Objective

Pre-clinical and uncontrolled studies in patients with systemic lupus erythematosus (SLE) showed that mesenchymal stromal cells (MSCs) have a potential therapeutic role in refractory cases. The optimal therapeutic strategy in these patients remain to be elucidated. Our aim was to test the hypothesis that repeated administrations of 1×10⁶/kg body weight of allogenic MSCs, that is a significantly lower dosage with respect to the fixed 1×10⁶ MSC used in animal models, can be effective in improving the clinical course of a murine SLE model.

Methods

Bone marrow derived MSCs were obtained from 12-week-old C57BL/6J mice. Seventy-five 8 weeks old female NZ mice were randomly assigned to receive via caudal vein the following alternative treatments: 1) single infusion of 10⁶ MSCs/kg body weight at 18 weeks of age (NZ_s18) or at at 22 weeks of age (NZ_s22); 2) multiple monthly infusions of 10⁶ MSCs/kg body weight starting at 18 weeks of age (NZ_M18) or at 22 weeks of age (NZ_M22); 3) saline infusions (NZ_c) Fifteen 8 weeks old C57BL/6J mice (Envigo, Huntingdon, UK) were used as untreated controls (C). Weekly, body weight was recorded and twenty-four hour urines were collected by metabolic cages for each animal; proteinuria was detected by dipstick analysis. At sacrifice, peripheral blood samples were collected from mice and anti-dsDNA antibodies were detected by enzyme immunoassorbent assay (ELISA) method using commercial kits. At sacrifice, kidneys were analyzed for histopathology and immunohistochemical analysis for B220, CD4, MPO, CD4^＋Foxp3, F40/80 infiltration was performed.

Results

Proteinuria occurrence was delayed NZ_S and NZ_M mice, no differences were observed in anti-dsDNA autoantibody titer among the groups at the different time-points; at 36 weeks, no significant differences were observed in term of nephritis scores. Inflammatory cells deposition (MPO and F4/80 positive cells) in NZ_M was significantly higher than in NZ and NZ_S. An overexpression of B lymphocytes (B220) was found in NZ_M while T regulatory cells (CD4^＋ Foxp3^＋ cells) were reduced in both NZ_S and NZ_M with respect to NZ_c.

Conclusions

Overall, our study failed to show a positive effect of a treatment with murine MSCs in this model and, for some aspects, even deleterious results seem to be observed.

Transcriptional repressor Blimp1 regulates follicular regulatory T-cell homeostasis and function

The B-lymphocyte-induced maturation protein 1 (Blimp1) regulates T-cell homeostasis and function. Loss of Blimp1 could double the proportion of follicular regulatory T (Tfr) cells. However, the effects that Blimp1 may have on the function of Tfr cells remain unknown. Here we document the function for Blimp1 in Tfr cells in vitro and in vivo. Data presented in this study demonstrate that Tfr cells indirectly inhibit the activation and differentiation of B cells by negatively regulating follicular helper T cells, so lowering the secretion of antibody. Lack of Blimp1 makes the immune suppression function of Tfr cells impaired in vitro. In the in vivo study, adoptive transfer of Tfr cells could reduce immune responses in germinal centres and relieve the muscle weakness symptoms of mice with experimental autoimmune myasthenia gravis. Blimp1 deficiency resulted in reduced suppressive ability of Tfr cells. This study identifies that Tfr cells are potent suppressors of immunity and are controlled by Blimp1.

Stem Cell Therapy in the Treatment of Rheumatic Diseases and Application in the Treatment of Systemic Lupus Erythematosus

Current systemic therapies help to improve the symptoms and quality of life for patients with severe life-threatening rheumatic diseases but provide no curative treatment. For the past two decades, preclinical and clinical studies of stem cell transplantation (SCT) have demonstrated tremendous therapeutic potential for patients with autoimmune rheumatic diseases. Herein, the current advances on stem cell therapies, both in animal models and clinical studies, are discussed, with particular attention on systemic lupus erythematosus (SLE). Despite extensive research and promising data, our knowledge on mechanisms of action for SCT, its administration route and timing, the optimal dose of cells, the cells’ fate and distribution in vivo, and the safety and efficacy of the treatments remains limited. Further research on stem cell biology is required to ensure that therapeutic safety and efficacy, as observed in animal models, can be successfully translated in clinical trials. Current understanding, limitations, and future directions for SCT with respect to rheumatic diseases are also discussed.

Mesenchymal Stem Cells Regulate the Innate and Adaptive Immune Responses Dampening Arthritis Progression

Mesenchymal stem cells (MSCs) are multipotent stem cells that are able to immunomodulate cells from both the innate and the adaptive immune systems promoting an anti-inflammatory environment. During the last decade, MSCs have been intensively studied in vitro and in vivo in experimental animal model of autoimmune and inflammatory disorders. Based on these studies, MSCs are currently widely used for the treatment of autoimmune diseases such as rheumatoid arthritis (RA) characterized by complex deregulation of the immune systems. However, the therapeutic properties of MSCs in arthritis are still controverted. These controversies might be due to the diversity of MSC sources and isolation protocols used, the time, the route and dose of MSC administration, the variety of the mechanisms involved in the MSCs suppressive effects, and the complexity of arthritis pathogenesis. In this review, we discuss the role of the interactions between MSCs and the different immune cells associated with arthritis pathogenesis and the possible means described in the literature that could enhance MSCs therapeutic potential counteracting arthritis development and progression.

Human embryonic stem cell-derived mesenchymal cells preserve kidney function and extend lifespan in NZB/W F1 mouse model of lupus nephritis

Adult tissue-derived mesenchymal stromal cells (MSCs) are showing promise in clinical trials for systemic lupus erythematosus (SLE). However, the inability to manufacture large quantities of functional cells from a single donor as well as donor-dependent variability in quality limits their clinical utility. Human embryonic stem cell (hESC)-derived MSCs are an alternative to adult MSCs that can circumvent issues regarding scalability and consistent quality due to their derivation from a renewable starting material. Here, we show that hESC-MSCs prevent the progression of fatal lupus nephritis (LN) in NZB/W F1 (BWF1) mice. Treatment led to statistically significant reductions in proteinuria and serum creatinine and preserved renal architecture. Specifically, hESC-MSC treatment prevented disease-associated interstitial inflammation, protein cast deposition, and infiltration of CD3⁺ lymphocytes in the kidneys. This therapy also led to significant reductions in serum levels of tumor necrosis factor alpha (TNFα) and interleukin 6 (IL-6), two inflammatory cytokines associated with SLE. Mechanistically, in vitro data support these findings, as co-culture of hESC-MSCs with lipopolysaccharide (LPS)-stimulated BWF1 lymphocytes decreased lymphocyte secretion of TNFα and IL-6, and enhanced the percentage of putative regulatory T cells. This study represents an important step in the development of a commercially scalable and efficacious cell therapy for SLE/LN.

Stem cell therapies for systemic lupus erythematosus: current progress and established evidence

Systemic lupus erythematosus is a multisystem autoimmune disease that, despite the advances in immunosuppressive medical therapies, remains potentially fatal in some patients, especially in treatment-refractory patients. In recent years, hematopoietic stem cells and, most recently, mesenchymal stem cells have been used to treat drug-resistant cases. Some progress was made, but there are still some issues to be resolved in the clinic.

Differential efficacy of human mesenchymal stem cells based on source of origin

Mesenchymal stem cells (MSCs) are useful in tissue repair but also possess immunomodulatory properties. Murine and uncontrolled human trials suggest efficacy of MSCs in treating lupus. Autologous cells are preferable; however, recent studies suggest that lupus-derived MSCs lack efficacy in treating disease. Thus, the optimum derivation of MSCs for use in lupus is unknown. It is also unknown which in vitro assays of MSC function predict in vivo efficacy. The objectives for this study were to provide insight into the optimum source of MSCs and to identify in vitro assays that predict in vivo efficacy. We derived MSCs from four umbilical cords, four healthy bone marrows (BMs), and four lupus BMs. In diseased MRL/lpr mice, MSCs from healthy BM and umbilical cords significantly decreased renal disease, whereas lupus BM MSCs only delayed disease. Current in vitro assays did not differentiate efficacy of the different MSCs. However, differences in MSC efficacy were observed in B cell proliferation assays. Our results suggest that autologous MSCs from lupus patients are not effective in treating disease. Furthermore, standard in vitro assays for MSC licensing are not predictive of in vivo efficacy, whereas inhibiting B cell proliferation appears to differentiate effective MSCs from ineffective MSCs.

Preclinical efficacy and mechanisms of mesenchymal stem cells in animal models of autoimmune diseases

Mesenchymal stem cells (MSCs) are present in diverse tissues and organs, including bone marrow, umbilical cord, adipose tissue, and placenta. MSCs can expand easily in vitro and have regenerative stem cell properties and potent immunoregulatory activity. They inhibit the functions of dendritic cells, B cells, and T cells, but enhance those of regulatory T cells by producing immunoregulatory molecules such as transforming growth factor-β, hepatic growth factors, prostaglandin E₂, interleukin-10, indolamine 2,3-dioxygenase, nitric oxide, heme oxygenase-1, and human leukocyte antigen-G. These properties make MSCs promising therapeutic candidates for the treatment of autoimmune diseases. Here, we review the preclinical studies of MSCs in animal models for systemic lupus erythematosus, rheumatoid arthritis, Crohn's disease, and experimental autoimmune encephalomyelitis, and summarize the underlying immunoregulatory mechanisms.

Novel approaches to lupus drug discovery using stem cell therapy. Role of mesenchymal-stem-cell-secreted factors

INTRODUCTION

Patients with systemic lupus erythematosus (SLE) are at increased risk for premature death, particularly among young adults, and present dilemmas regarding drug efficacy versus toxicity. Novel therapeutic strategies have included the use of mesenchymal stem cell (MSC) therapies that are promising but still have limitations. In several disease models, it has become apparent that MSCs do not necessarily replace diseased tissues but rather exert complex paracrine effects that are mediated by their extracellular-secreted products.

AREAS COVERED

In this review, the authors highlight the data on MSC treatment of SLE and related mechanisms of actions. This data includes the recent evidence that MSC-secreted factors such as extracellular microvesicles (MVs) are important mediators of MSC therapy. Among MVs, the authors delineate the role of exosomes as triggers of regenerative effects in target cells, mediated by transfer of proteins, mRNAs or microRNAs. The authors also outline some of the biological and regulatory restraints encountered by MSC therapy, in contrast to the potential advantages of MSC-derived exosomes as new therapeutic tools in SLE.

EXPERT OPINION

There is concern about reproducible data on the use of MSC therapy in rheumatic diseases and specifically SLE. Although most experts consider MSCs to be safe, there are still worries over donor variability, immune-mediated rejection, culture-induced senescence, loss of functional properties and genetic instability or eventual malignant transformation. MSC-released factors could avoid most limiting factors associated with cell therapy and are therefore expected to provide a new and safe therapeutic option at an affordable cost.

Kallikrein transduced mesenchymal stem cells protect against anti-GBM disease and lupus nephritis by ameliorating inflammation and oxidative stress

Previously we have shown that kallikreins (klks) play a renoprotective role in nephrotoxic serum induced nephritis. In this study, we have used mesenchymal stem cells (MSCs) as vehicles to deliver klks into the injured kidneys and have measured their therapeutic effect on experimental antibody induced nephritis and lupus nephritis. Human KLK-1 (hKLK1) gene was transduced into murine MSCs using a retroviral vector to generate a stable cell line, hKLK1-MSC, expressing high levels of hKLK1. 129/svj mice subjected to anti-GBM induced nephritis were transplanted with 10⁶ hKLK1-MSCs and hKLK1 expression was confirmed in the kidneys. Compared with vector-MSCs injected mice, the hKLK1-MSCs treated mice showed significantly reduced proteinuria, blood urea nitrogen (BUN) and ameliorated renal pathology. Using the same strategy, we treated lupus-prone B6.Sle1.Sle3 bicongenic mice with hKLK1-MSCs and demonstrated that hKLK1-MSCs delivery also attenuated lupus nephritis. Mechanistically, hKLK1-MSCs reduced macrophage and T-lymphocyte infiltration into the kidney by suppressing the expression of inflammation cytokines. Moreover, hKLK1 transduced MSCs were more resistant to oxidative stress-induced apoptosis. These findings advance genetically modified MSCs as potential gene delivery tools for targeting therapeutic agents to the kidneys in order to modulate inflammation and oxidative stress in lupus nephritis.