Mesenchymal stem cells in autoimmune disease

Comparative interleukins and chemokines analysis of mice mesenchymal stromal cells infected with Mycobacterium tuberculosis H37Rv and H37Ra

Inflammatory pathways involving Mesenchymal stromal cells (MSCs) play an important role in Mycobacterium tuberculosis (Mtb) infection. H37Rv (Rv) is a standard virulent strain, however, H37Ra (Ra) is a strain with reduced virulence. Interleukins and chemokines production are known to promote inflammation resistance in mammalian cells and is recently reported to regulate mycobacterial immunopathogenesis via inflammatory responses. MSCs are very important cells during Mtb infection. However, the different expressions of interleukins and chemokines in the process of Mtb-infected MSCs between Ra and Rv remain unclear. We used the techniques of RNA-Seq, Q-RT-PCR, ELISA, and Western Blotting. We have shown that Rv infection significantly increased mRNA expressions of Mndal, Gdap10, Bmp2, and Lif, thereby increasing more differentiation of MSCs compared with Ra infection in MSCs. Further investigation into the possible mechanisms, we found that Rv infection enhanced more inflammatory response (Mmp10, Mmp3, and Ptgs2) through more activation of the TLR2-MAP3K1-JNK pathway than did Ra infection in MSCs. Further action showed that Rv infection enhanced more Il1α, Il6, Il33, Cxcl2, Ccl3, and Ackr3 production than did Ra infection. Rv infection showed more expressions of Mmp10, Mmp3, Ptgs2, Il1α, Il6, Il33, Cxcl2, Ccl3, and Ackr3 possibly through more active TLR2-MAP3K1-JNK pathway than did Ra infection in MSCs. MSCs may therefore be a new candidate for the prevention and treatment of tuberculosis.

MicroRNA-20b carried by mesenchymal stem cell-derived extracellular vesicles protects alveolar epithelial type II cells from Mycobacterium tuberculosis infection in vitro

Mesenchymal stem cells (MSCs) have been largely used for their immunomodulatory and regenerative properties in the treatment of immune-based disorders and bacterial infections. This study explores the function of MSC-derived extracellular vesicles (MSC-EVs) in alveolar epithelial type II cells (AECII) against Mycobacterium tuberculosis (MTB) infection. EVs were extracted from the acquired MSCs. AECII-like MLE-15 and A549 cells were treated with MSC-EVs and then subjected to MTB infection. MSC-EVs treatment significantly prevented the increase in bacterial load, and it prevented the production of proinflammatory cytokines in cells induced by MTB infection. MicroRNA-20b (miR-20b) was upregulated in cells after MSC-EVs treatment. Artificial inhibition of miR-20b blocked the protective effects of MSC-EVs against MTB infection. A Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis was performed to analyze the key molecules involved in the immune regulation in cells mediated by miR-20b. miR-20b directly targeted nuclear factor of activated T cells 5 (NFAT5) and inactivated the Toll-Like Receptor (TLR) signaling pathway by reducing the formation of TLR2-TLR4 dimer after MTB infection. In conclusion, this study suggests that MSC-EVs carry miR-20b to inhibit NFAT5 and inactivate the TLR signaling pathway, thus mediating innate immune response and preventing AECII from MTB infection-induced damage.

Safety and Efficacy of Mesenchymal Stromal Cells and Other Cellular Therapeutics in Rheumatic Diseases in 2022: A review of what we know so far

Although there are a number of new immunosuppressives and biologics approved for treating various autoimmune/inflammatory rheumatic diseases, there remain a substantial number of patients who have no clinical response or limited clinical response to these available treatments. Use of cellular therapies is a novel approach for the treatment of autoimmune/inflammatory rheumatic diseases with perhaps enhanced efficacy and less toxicity than current therapies. Autologous hematopoietic stem cell transplants were the first foray into cellular therapies with proven efficacy in scleroderma and multiple sclerosis. Newer yet unproven cellular therapies include allogenic mesenchymal stromal cells, shown effective in graft vs host disease and in healing of Crohn's fistulas. CAR-T cells are effective in various malignancies with possible usage in rheumatic diseases, as shown in preclinical studies in murine lupus and recently in human lupus. T regulatory cells are one of the master controllers of the immune response and are decreased in number and/or effectiveness in specific autoimmune diseases. Expansion of autologous T regulatory cells is an attractive approach to controlling autoimmunity. There are a number of other regulatory cells in the immune system including regulatory B cells, dendritic cells, macrophages, and other T cell types that are early in development. In this review, the current evidence for efficacy and mechanisms of actions of cellular therapies already in use or in clinical trials in human autoimmune diseases will be discussed including limitations of these therapies and potential side effects.

Preconditioning with interleukin-1 beta and interferon-gamma enhances the efficacy of human umbilical cord blood-derived mesenchymal stem cells-based therapy via enhancing prostaglandin E2 secretion and indoleamine 2,3-dioxygenase activity in dextran sulfate sodium-induced colitis

Preconditioning with inflammatory cytokines has improved mesenchymal stem cells characteristics, including differentiation and immunomodulating functions. In this study, we developed a preconditioning combination strategy using interleukin-1beta (IL-1β) and interferon-gamma (IFN-γ) to enhance the immuneregulatory ability of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs). Our results showed that hUCB-MSCs preconditioned with IL-1β and IFN-γ (primed hUCB-MSCs) created a statistically significant decrease in peripheral blood mononuclear cell proliferation, indicating that their immunosuppressive ability was increased. The secretion of PGE2, cyclooxygenase 2 mRNA expression, and indoleamine 2,3-dioxygenase (IDO) mRNA expression in primed hUCB-MSCs was significantly higher than those in the untreated hUCB-MSCs or the IL-1β or IFN-γ only treated hUCB-MSCs. When inhibitors of IDO and PGE2 were treated, peripheral blood mononuclear cell proliferation, which is inhibited by primed hUCB-MSCs, was recovered. We found that Th1 T cell differentiation was also inhibited by PGE2 and IDO in the primed hUCB-MSCs, and Tregs differentiation was increased by PGE2 and IDO in the primed hUCB-MSCs. Furthermore, the primed hUCB-MSCs as well as supernatants increase CD4⁺ T cells migration. We demonstrated the therapeutic effects of primed hUCB-MSCs in dextran sulfate sodium-induced colitis model. In conclusion, we have demonstrated that primed hUCB-MSCs simultaneously enhance PGE2 and IDO and greatly improve the immunoregulatory capacity of MSCs, and we have developed an optimal condition for pretreatment of MSCs for the treatment of immune diseases. Our results raise the possibility that the combination of PGE2 and IDO could be therapeutic mediators for controlling immunosuppression of MSCs.

Application of the allogenic mesenchymal stem cells in the therapy of the bladder tuberculosis

Urogenital tuberculosis (TB) often leads to contraction of the bladder, a reduction of the urinary reservoir capacity, and, in the latest stage, to real microcystitis up to full obliteration. Bladder TB Stage 4 is unsuitable for conservative therapy, and cystectomy with subsequent enteroplasty is indicated. In this study, using a model of bladder TB in New Zealand rabbits, the therapeutic efficacy of the interstitial injection of autologous bone-derived mesenchymal stem cells (MSCs) combined with standard anti-TB treatment in the restoration of the bladder function was demonstrated. For analysis of the MSC distribution in tissues, the latter were labelled with superparamagnetic iron oxide nanoparticles. In vitro studies demonstrated the high intracellular incorporation of nanoparticles and the absence of cytotoxicity on MSC viability and proliferation. A single-dose administration of MSCs into the bladder mucosal layer significantly reduced the wall deformation and inflammation and hindered the development of fibrosis, which was proven by the subsequent histological assay. Confocal microscopy studies of the bladder cryosections confirmed the presence of superparamagnetic iron oxide nanoparticle-labelled MSCs in different bladder layers of the treated animals, thus indicating the role of stem cells in bladder regeneration.

Mesenchymal stem cells in obesity: insights for translational applications

Obesity is now a major public health problem worldwide. Lifestyle modification to reduce the characteristic excess body adiposity is important in the treatment of obesity, but effective therapeutic intervention is still needed to control what has become an obesity epidemic. Unfortunately, many anti-obesity drugs have been withdrawn from market due to adverse side effects. Bariatric surgery therefore remains the most effective therapy for severe cases, although such surgery is invasive and researchers continue to seek new control strategies for obesity. Mesenchymal stem cells (MSCs) are a major source of adipocyte generation, and studies have been conducted into the potential roles of MSCs in treating obesity. However, despite significant progress in stem cell research and its potential applications for obesity, adipogenesis is a highly complex process and the molecular mechanisms governing MSC adipogenesis remain ill defined. In particular, successful clinical application of MSCs will require extensive identification and characterization of the transcriptional regulators controlling MSC adipogenesis. Since obesity is associated with the incidence of multiple important comorbidities, an in-depth understanding of the relationship between MSC adipogenesis and the comorbidities of obesity is also necessary to evaluate the potential of effective and safe MSC-based therapies for obesity. In addition, brown adipogenesis is an attractive topic from the viewpoint of therapeutic innovation and future research into MSC-based brown adipogenesis could lead to a novel breakthrough. Ongoing stem cell studies and emerging research fields such as epigenetics are expected to elucidate the complicated mechanisms at play in MSC adipogenesis and develop novel MSC-based therapeutic options for obesity. This review discusses the current understanding of MSCs in adipogenesis and their potential clinical applications for obesity.

Adipose-Derived Mesenchymal Stem Cells Reduce Lymphocytic Infiltration in a Rabbit Model of Induced Autoimmune Dacryoadenitis

Purpose

To investigate the immunoregulatory roles of adipose-derived mesenchymal stem cells (ADSCs) in autoimmune dacryoadenitis.

Methods

Rabbits were treated with ADSCs or phosphate-buffered solution on days 1, 3, 5, 7, and 9 after injection of activated peripheral blood lymphocytes, and clinical scores were determined by assessing tear production, break-up time, and fluorescein and hematoxylin and eosin staining. Inflammatory response was determined by measuring the expression of different mediators of inflammation in the lacrimal glands. The Th1/Th17-mediated autoreactive responses were evaluated by determining the proliferative response and the expression of cytokine genes and the lineage-determining transcription factors. The frequency of regulatory T cells (Tregs) was also examined.

Results

The ADSC-treated rabbits showed decreased autoimmune responses, and the secretory function of their lacrimal gland was restored significantly. Treatment with ADSCs downregulated the Th1 and Th17 responses but enhanced Tregs function. In addition, ADSC treatment noticeably suppressed the expression of matrix metalloproteinase (MMP)-9, MPP-2, IL-1β, and IL-6, whereas it enhanced the expression of the anti-inflammatory cytokine IL-10.

Conclusions

Our results demonstrated that ADSC administration efficiently ameliorates autoimmune dacryoadenitis mainly via modulating Th1/Th17 responses.

Modulatory effects of mesenchymal stem cells on leucocytes and leukemic cells: A double-edged sword?

Mesenchymal stem cells (MSCs) have drawn much attention amongst stem cell researchers in the past few decades. The ability of the MSC to differentiate into cells of mesodermal and non-mesodermal origins has made them an attractive approach for cell-based therapy and regenerative medicine. The MSCs have immunosuppressive activities that may have considerable therapeutic values in autoimmune diseases. However, despite the many beneficial effects reported, there is a growing body of evidence, which suggests that MSCs could be a culprit of enhanced tumour growth, metastasis and drug resistance in leukaemia, via some modulatory effects. Many controversies regarding the interactions between MSCs and leukaemia still exist. Furthermore, the role of MSCs in leukemogenesis and its progression remain largely unknown. Hence it is important to understand how the MSCs modulate leukaemia before these cells could be safely used in the treatment of leukaemia patients.

The Effect of Bone Marrow-Derived Mesenchymal Stem Cells and Their Conditioned Media Topically Delivered in Fibrin Glue on Chronic Wound Healing in Rats

Bone marrow-derived mesenchymal stem cells (BM-MSCs) represent a modern approach for management of chronic skin injuries. In this work, we describe BM-MSCs application versus their conditioned media (CM) when delivered topically admixed with fibrin glue to enhance the healing of chronic excisional wounds in rats. Fifty-two adult male rats were classified into four groups after induction of large-sized full-thickness skin wound: control group (CG), fibrin only group (FG), fibrin + MSCs group (FG + SCs), and fibrin + CM group (FG + CM). Healing wounds were evaluated functionally and microscopically. Eight days after injury, number of CD68+ macrophages infiltrating granulation tissue was considerably higher in the latter two groups. Although--later--none of the groups depicted a substantially different healing rate, the quality of regenerated skin was significantly boosted by the application of either BM-MSCs or their CM both (1) structurally as demonstrated by the obviously increased mean area percent of collagen fibers in Masson's trichrome-stained skin biopsies and (2) functionally as supported by the interestingly improved epidermal barrier as well as dermal tensile strength. Thus, we conclude that topically applied BM-MSCs and their CM-via fibrin vehicle--could effectively improve the quality of healed skin in chronic excisional wounds in rats, albeit without true acceleration of wound closure.

CTLA4 overexpressing adipose tissue-derived mesenchymal stem cell therapy in a dog with steroid-refractory pemphigus foliaceus

Background

Canine pemphigus foliaceus is an autoimmune antibody-mediated skin disease characterized by acantholysis. The objective of this case report is to present the successful management of steroid refractory pemphigus foliaceus with cytotoxic T-lymphocyte antigen 4 (CTLA4)-overexpressing adipose tissue mesenchymal stem cells (ATMSCs).

Case presentation

A 10-year-old, 12.3-kg, castrated male Shih Tzu presented with severe pruritus and anorexia. The diagnosis of pemphigus foliaceus was made based on its history, physical examination, and histopathology results of a skin biopsy. Treatment with prednisolone and combination therapy of other immunosuppressive drugs had failed; therefore, immunosuppressive gene, CTLA4 overexpressing ATMSCs (CTLA4-ATMSCs) and/or naive ATMSCs administration was performed with the consent of the owner. ATMSCs were administered 21 times over a period of 20 months with intervals of 2 to 8 week. Prednisolone was gradually tapered concurrently and no relapse of the clinical signs was observed. After the termination of CTLA4-ATMSCs and/or naive ATMSCs treatment, the skin lesions had improved and could be managed with a low dose of prednisolone for 12 months.

Conclusion

CTLA4-ATMSCs or naive ATMSCs transplantation may be beneficial as adjunctive therapy to initiate and maintain the remission of skin lesions caused by pemphigus foliaceus in veterinary medicine.

Differentiation and migration of bone marrow mesenchymal stem cells transplanted through the spleen in rats with portal hypertension

Aims

The goals of this paper were to evaluate the differentiation of bone marrow mesenchymal stem cells (BMSCs) into hepatocyte-like cells invitro, and to determine whether stem cells can migrate and plant into the liver with portal hypertension accompanied by the end-stage of liver disease.

Methods

BMSCs were isolated from rats and amplified with hepatocyte growth factor (HGF) and fibroblast growth factor-4 (FGF-4). The expression of alpha-fetoprotein (AFP), cytokeratin 18 (CK-18), and albumin (ALB) was detected by immunofluorescence in induced cells. Rats were randomly divided into experimental (with common bile duct ligation) and control groups. After injection of fluorescence labeled cells, cell distribution was observed under a fluorescence microscope. The integrated optical density (IOD) and cell distribution scores were evaluated using Image-Pro Plus 6.0 software. The portal pressure was measured before the rats were killed.

Results

After being induced with HGF and FGF-4, the Golgi apparatus, endoplasmic reticulum, ribosomes, and mitochondria all significantly increased in the fifth generation cells. Immunofluorescent analysis showed that the induced cells expressed AFP, CK-18, and ALB. BMSCs were stained by CM-Dil, and the labeling rate was as high as 95.5%. The portal pressure in experimental group was much higher than that of the control group (18.04±2.35 vs. 9.75±1.40cm H₂O p<0.01). The IOD of transplanted cells in the experimental group was also significantly higher than that of the control group (11.30±2.09×10⁵ vs. 2.93±0.88×10⁵, p<0.01). In addition, the cell distribution score in the experimental group was lower than that of the control group (1.99±0.36 vs. 2.36±0.27, P<0.05).

Conclusions

The combination of HGF and FGF-4 induces the differentiation of BMSCs into hepatocyte-like cells, which express AFP, CK-18, and ALB. In addition, the recruitment of BMSCs (after transplantation in the spleen) was improved in rats with portal hypertension.

Stem cell-like dog placenta cells afford neuroprotection against ischemic stroke model via heat shock protein upregulation

In this study, we investigated the dog placenta as a viable source of stem cells for stroke therapy. Immunocytochemical evaluation of phenotypic markers of dog placenta cells (DPCs) cultured in proliferation and differentiation medium revealed that DPCs expressed both stem cell and neural cell markers, respectively. Co-culture with DPCs afforded neuroprotection of rat primary neural cells in a dose-dependent manner against oxygen-glucose deprivation. Subsequent in vivo experiments showed that transplantation of DPCs, in particular intravenous and intracerebral cell delivery, produced significant behavioral recovery and reduced histological deficits in ischemic stroke animals compared to those that received intra-arterial delivery of DPCs or control stroke animals. Furthermore, both in vitro and in vivo studies implicated elevated expression of heat shock protein 27 (Hsp27) as a potential mechanism of action underlying the observed therapeutic benefits of DPCs in stroke. This study supports the use of stem cells for stroke therapy and implicates a key role of Hsp27 signaling pathway in neuroprotection.

Inflammatory serum proteome pattern in mice fed a high-fat diet

To investigate the influence of diet on serum protein pattern, mice were fed for 8 weeks either control chow or a high-fat diet (containing 21 % w/w milk fat and 0.2 % w/w cholesterol); sera were collected and analyzed by 2-DE. The main positive acute-phase reactant proteins, haptoglobin and hemopexin, were significantly up-regulated in animals receiving the high-fat diet. Data on all other proteins also pointed to an inflammatory condition in these animals. The largest change in concentration was observed for carboxylesterase N, a circulating enzyme seldom connected with lipid metabolism in earlier reports. These observations agree with the notion of a link between diet-induced hyperlipidemia and the inflammatory component of its cardiovascular sequels in humans, but the effects in the experimental animals are massive and obviously affect most of the major serum proteins.

Autologous bone marrow cell infusions suppress tumor initiation in hepatocarcinogenic mice with liver cirrhosis

We have previously reported the efficacy and safety of autologous bone marrow cell infusion (ABMi) therapy for liver cirrhosis patients without hepatocellular carcinoma in a multicenter clinical trial. However, since liver cirrhosis is highly oncogenic, evaluation of the effects of ABMi on the mechanisms of hepatocarcinogenesis is of great importance. Therefore, frequent ABMi was performed in hepatocarcinogenic mice, and its effects on hepatocarcinogenesis were analyzed. The N-nitrosodiethylamine (DEN)/green fluorescent protein (GFP)-carbon tetrachloride (CCl(4) ) model was developed by administering DEN once, followed by repeated administration of CCl(4) intraperitoneally as for the control group. In the administration (ABMi) group, GFP-positive bone marrow cells were infused through a tail vein. The kinetics of hepatocarcinogenesis were evaluated histologically 4.5 months after DEN treatment. At 4.5 months, there was significantly lower incidence of foci and tumors in the ABMi group, and they were smaller in number, while their size was almost equal. No GFP-positive tumors were found in ABMi livers. Moreover, ABMi livers showed significantly reduced liver fibrosis, consistent with significantly lower 8-hydroxy-2'-deoxyguanosine levels, higher superoxide dismutase activity, and increased nuclear translocation of nuclear factor-erythroid 2 p45-related factor 2. These results demonstrate that frequent ABMi might contribute to suppressed tumor initiation during stages of hepatocarcinogenesis, consistent with improvements in liver fibrosis and stabilization of redox homeostasis.

Direct transplantation of mesenchymal stem cells into the knee joints of Hartley strain guinea pigs with spontaneous osteoarthritis

INTRODUCTION

Mesenchymal stem cells (MSCs) can differentiate into various connective tissue cells. Several techniques have been used for the clinical application of MSCs in articular cartilage repair; however, there are many issues associated with the selection of the scaffold material, including its ability to support cell viability and differentiation and its retention and degradation in situ. The application of MSCs via a scaffold also requires a technically demanding surgical procedure. The aim of this study was to test the outcome of intra-articular transplantation of mesenchymal stem cells suspended in hyaluronic acid (HA) in the knee joints of Hartley strain guinea pigs with spontaneous osteoarthritis (OA).

METHODS

Commercially available human MSCs were cultured, labeled with carboxyfluorescein diacetate succinimidyl ester (CFDA-SE), suspended in either PBS or HA, and injected into the knee joints of 7-month-old animals. The control animals were injected with either PBS or HA alone. The animals were sacrificed at 1, 3, and 5 weeks post transplantation, the knee joints harvested, and fluorescent microscopic analysis was performed. Histological and immunohistochemical analysis were performed at 5 weeks post transplantation.

RESULTS

At 5 weeks post transplantation, partial cartilage repair was noted in the HA-MSC group but not in the other groups. Examination of CFDA-SE-labeled cells demonstrated migration, differentiation, and proliferation of MSC in the HA-MSC group. There was strong immunostaining for type II collagen around both residual chondrocytes and transplanted MSCs in the OA cartilage.

CONCLUSION

This scaffold-free and technically undemanding technique appears to result in the regeneration of articular cartilage in the spontaneous OA animal model. Although further examination of the long-term effects of transplantation is necessary, the findings suggest that intra-articular injection of HA-MSC mixture is potentially beneficial for OA.

Stem cells in liver failure

Orthotopic liver transplantation (OLT) represents the only reliable therapeutic approach for acute liver failure (ALF), liver failure associated to end-stage chronic liver diseases (CLD) and non-metastatic liver cancer. The clinical impact of liver failure is relevant because of the still high ALF mortality and the increasing worldwide prevalence of cirrhosis that, in turn, is the main predisposing cause for hepatocellular carcinoma (HCC). Moreover, in the next decade because an increased number of patients reaching end-stage disease and requiring OLT may face a shortage of donor livers. This clinical scenario led several laboratories to explore the feasibility and efficiency of alternative approaches, involving cellular therapy, to counteract liver failure. The present chapter overviews results and concepts emerged from recent experimental and clinical studies in which adult or embryonic hepatocytes, hepatic stem/progenitor cells, induced pluripotent stem (iPS) cells as well as extrahepatic stem cells have been used as putative transplantable cell sources.

Isolation and characterization of true mesenchymal stem cells derived from human term decidua capable of multilineage differentiation into all 3 embryonic layers

OBJECTIVE

The objective of the study was to isolate and characterize a population of mesenchymal stem cells (MSCs) from human term placental membranes.

STUDY DESIGN

We isolated an adherent cell population from extraembryonic membranes. Morphology, phenotype, growth characteristics, karyotype, and immunological and differentiation properties were analyzed.

RESULTS

The isolated placental MSCs were from maternal origin and named as decidua-derived mesenchymal stem cells (DMSCs). DMSCs differentiated into derivatives of all germ layers. It is the first report about placental MSC differentiation into alveolar type II cells. Clonally expanded DMSCs differentiated into all embryonic layers, including pulmonary cells. DMSCs showed higher life span than placental cells from fetal origin and proliferated without genomic instability.

CONCLUSION

The data suggest that DMSCs are true multipotent MSCs, distinguishing them from other placental MSCs. DMSCs could be safely used in the mother as a potential source of MSCs for pelvic floor dysfunctions and immunological diseases. Additionally, frozen DMSCs can be stored for both autologous and allogeneic tissue regeneration.

Trafficking mesenchymal stem cell engraftment and differentiation in tumor-bearing mice by bioluminescence imaging

The objective of the study was to track the distribution and differentiation of mesenchymal stem cells (MSCs) in tumor-bearing mice. The 4T1 murine breast cancer cells were labeled with renilla luciferase-monomeric red fluorescence protein (rLuc-mRFP) reporter gene. The MSCs labeled with firefly luciferase-enhanced green fluorescence protein (fLuc-eGFP) reporter gene (MSCs-R) were isolated from L2G85 transgenic mice that constitutively express fLuc-eGFP reporter gene. To study the tumor tropism of MSCs, we established both subcutaneous and lung metastasis models. In lung metastasis tumor mice, we injected MSCs-R intravenously either on the same day or 4 days after 4T1 tumor cell injection. In subcutaneous tumor mice, we injected MSCs-R intravenously 7 days after subcutaneous 4T1 tumor inoculation. The tumor growth was monitored by rLuc bioluminescence imaging (BLI). The fate of MSCs-R was monitored by fLuc BLI. The localization of MSCs-R in tumors was examined histologically. The osteogenic and adipogenic differentiation of MSCs-R was investigated by alizarin red S and oil red O staining, respectively. The mechanism of the dissimilar differentiation potential of MSCs-R under different tumor microenvironments was investigated. We found that the 4T1 cells were successfully labeled with rLuc-mRFP. The MSCs-R isolated from L2G85 transgenic mice constitutively express fLuc-eGFP reporter gene. When injected intravenously, MSCs-R survived, proliferated, and differentiated in tumor sites but not elsewhere. The localization of GFP(+) MSCs-R in tumor lesions was confirmed ex vivo. In conclusion, the MSCs-R can selectively localize, survive, and proliferate in both subcutaneous tumor and lung metastasis as evidenced by noninvasive bioluminescence imaging and ex vivo validation. The MSCs-R migrated to lung tumor differentiated into osteoblasts, whereas the MSCs-R targeting subcutaneous tumor differentiated into adipocytes.

Mesenchymal stem cell transplantation attenuates blood brain barrier damage and neuroinflammation and protects dopaminergic neurons against MPTP toxicity in the substantia nigra in a model of Parkinson's disease

Immunomodulatory effects of transplanted mesenchymal stem cells (MSCs) in the treatment of Parkinson's disease were studied in the MPTP-induced mouse model. MPTP treatment induced a significant loss of dopaminergic neurons, decreased expressions of claudin 1, claudin 5 and occludin in the substantia nigra compacta (SNc), and functional damage of the blood brain barrier (BBB). Our study further discovered that infiltration of MBLs into the brain to bind with microglia was detected in the SNc of MPTP-treated mice, suggesting that the BBB compromise and MBL infiltration might be involved in the pathogenesis of MPTP-induced PD. In addition, MPTP treatment also increased the expression of mannose-binding lectins (MBLs) in the liver tissue. Intravenous transplantation of MSCs into MPTP-treated mice led to recovery of BBB integrity, suppression of MBL infiltration at SNc and MBL expression in the liver, suppression of microglial activation and prevention of dopaminergic neuron death. No transplanted MSCs were observed to differentiate into dopaminergic neurons, while the MSCs migrated into the SNc and released TGF-beta1 there. Therefore, intravenous transplantation of MSCs which protect dopaminergic neurons from MPTP toxicity may be engaged in anyone or a combination of these mechanisms: repair of the BBB, reduction of MBL in the brain, inhibition of microglial cytotoxicity, and direct protection of dopaminergic neurons.

Analysis of allogenicity of mesenchymal stem cells in engraftment and wound healing in mice

Studies have shown that allogeneic (allo-) bone marrow derived mesenchymal stem cells (BM-MSCs) may enhance tissue repair/regeneration. However, recent studies suggest that immune rejection may occur to allo-MSCs leading to reduced engraftment. In this study, we compared allo-BM-MSCs with syngeneic BM-MSCs or allo-fibroblasts in engraftment and effect in wound healing. Equal numbers of GFP-expressing allo-BM-MSCs, syngeneic BM-MSCs or allo-fibroblasts were implanted into excisional wounds in GFP-negative mice. Quantification of GFP-expressing cells in wounds at 7, 14 and 28 days indicated similar amounts of allogeneic or syngeneic BM-MSCs but significantly reduced amounts of allo-fibroblasts. With healing progression, decreasing amounts of allogeneic and syngeneic BM-MSCs were found in the wound; however, the reduction was more evident (2 fold) in allo-fibroblasts. Similar effects in enhancing wound closure were found in allogeneic and syngeneic BM-MSCs but not in allo-fibroblasts. Histological analysis showed that allo-fibroblasts were largely confined to the injection sites while allo-BM-MSCs had migrated into the entire wound. Quantification of inflammatory cells in wounds showed that allo-fibroblast- but not allo-BM-MSC-treated wounds had significantly increased CD45+ leukocytes, CD3+ lymphocytes and CD8+ T cells. Our study suggests that allogeneic BM-MSCs exhibit ignorable immunogenicity and are equally efficient as syngeneic BM-MSCs in engraftment and in enhancing wound healing.

Biodistribution, long-term survival, and safety of human adipose tissue-derived mesenchymal stem cells transplanted in nude mice by high sensitivity non-invasive bioluminescence imaging

Cultivated murine bone marrow mesenchymal stem cells (MSCs) frequently accumulate chromosome abnormalities, become oncogenically transformed, and generate sarcomas when transplanted in mice. Although human MSCs appear to be more resistant, oncogenic transformation has also been observed in MSCs cultivated past the senescence phase. Cell therapy for tissue regeneration using human autologous MSCs requires transplantation of cells previously expanded in vitro. Thus, an important concern is to determine if oncogenic transformation is a necessary outcome of the expansion procedures. We have analyzed the proliferation capacity, organ colonization, and oncogenicity of enhanced green fluorescent protein and luciferase-labeled human adipose tissue-derived mesenchymal stem cells (hAMSCs), implanted in immunocompromised mice during a prolonged time period (8 months) using a non-invasive bioluminescence imaging procedure. Our data indicates that the liver was the preferred target organ for colonization by intramuscular or intravenous implantation of hAMSCs. The implanted cells tended to maintain a steady state, population did not proliferate rapidly after implantation, and no detectable chromosomal abnormalities nor tumors formed during the 8 months of residence in the host's tissues. It would appear that hAMSCs, contrary to their murine correlatives, could be safe candidates for autologous cell therapy procedures since in our experiments they show undetectable predisposition to oncogenic transformation after cultivation in vitro and implantation in mice.

Stem cell therapy for liver disease: parameters governing the success of using bone marrow mesenchymal stem cells

BACKGROUND & AIMS

Liver transplantation is the primary treatment for various end-stage hepatic diseases but is hindered by the lack of donor organs and by complications associated with rejection and immunosuppression. There is increasing evidence to suggest the bone marrow is a transplantable source of hepatic progenitors. We previously reported that multipotent bone marrow-derived mesenchymal stem cells differentiate into functional hepatocyte-like cells with almost 100% induction frequency under defined conditions, suggesting the potential for clinical applications. The aim of this study was to critically analyze the various parameters governing the success of bone marrow-derived mesenchymal stem cell-based therapy for treatment of liver diseases.

METHODS

Lethal fulminant hepatic failure in nonobese diabetic severe combined immunodeficient mice was induced by carbon tetrachloride gavage. Mesenchymal stem cell-derived hepatocytes and mesenchymal stem cells were then intrasplenically or intravenously transplanted at different doses.

RESULTS

Both mesenchymal stem cell-derived hepatocytes and mesenchymal stem cells, transplanted by either intrasplenic or intravenous route, engrafted recipient liver, differentiated into functional hepatocytes, and rescued liver failure. Intravenous transplantation was more effective in rescuing liver failure than intrasplenic transplantation. Moreover, mesenchymal stem cells were more resistant to reactive oxygen species in vitro, reduced oxidative stress in recipient mice, and accelerated repopulation of hepatocytes after liver damage, suggesting a possible role for paracrine effects.

CONCLUSIONS

Bone marrow-derived mesenchymal stem cells can effectively rescue experimental liver failure and contribute to liver regeneration and offer a potentially alternative therapy to organ transplantation for treatment of liver diseases.

Effects of plating density and culture time on bone marrow stromal cell characteristics

OBJECTIVE

Bone marrow stromal cells (MSC) are multipotent adult stem cells that have emerged as promising candidates for cell therapy in disorders including cardiac infarction, stroke, and spinal cord injury. While harvesting methods used by different laboratories are relatively standard, MSC culturing protocols vary widely. This study is aimed at evaluating the effects of initial plating density and total time in culture on proliferation, cell morphology, and differentiation potential of heterogeneous MSC cultures and more homogeneous cloned subpopulations.

MATERIALS AND METHODS

Rat MSC were plated at 20, 200, and 2000 cells/cm(2) and grown to 50% confluency. The numbers of population doublings and doubling times were determined within and across multiple passages. Changes in cell morphology and differentiation potential to adipogenic, chondrogenic, and osteogenic lineages were evaluated and compared among early, intermediate, and late passages, as well as between heterogeneous and cloned MSC populations.

RESULTS

We found optimal cell growth at a plating density of 200 cells/cm(2). Cultures derived from all plating densities developed increased proportions of flat cells over time. Assays for chondrogenesis, osteogenesis, and adipogenesis showed that heterogeneous MSC plated at all densities sustained the potential for all three mesenchymal phenotypes through at least passage 5; the flat subpopulation lost adipogenic and chondrogenic potential.

CONCLUSION

Our findings suggest that the initial plating density is not critical for maintaining a well-defined, multipotent MSC population. Time in culture, however, affects cell characteristics, suggesting that cell expansion should be limited, especially until the specific characteristics of different MSC subpopulations are better understood.

Bone marrow-derived mesenchymal stem cells for treatment of heart failure: is it all paracrine actions and immunomodulation?

Despite significant advances in medical and surgical management of heart failure, mostly of ischaemic origin, the mortality and morbidity associated with it continue to be high. Pluripotent stem cells are being evaluated for treatment of heart failure. Bone marrow-derived mesenchymal stem cells (MSCs) have been extensively studied. Emerging evidence suggests that locally delivered MSCs can lead to an improvement in ventricular function, but the cellular and molecular mechanisms involved remain unclear. Myocardial regeneration, as proposed by many researchers as the underlying mechanism, has failed to convince the scientific community. Recently some authors have ascribed improvement in ventricular function to paracrine actions of MSCs.A lot has been written about the host immune response triggered by embryonic stem cells and the consequent need for immunosuppression. Not enough work has been done on immune interactions involving allogeneic bone marrow cells. Full potential of stem cell therapy can be realised only when we are able to use allogeneic cells. The potential use of MSCs in cellular therapy has recently prompted researchers to look into their interaction with the host immune response. MSCs have immunomodulatory properties. They cause suppression of proliferation of alloreactive T cells in a dose-dependent manner.Tissue injury causes inflammation and release of several chemokines, cytokines and growth factors. They can cause recruitment of bone marrow-derived MSCs to the injured area. We review the literature on paracrine actions and immune interactions of allogeneic MSCs.

Cell therapy using allogeneic bone marrow mesenchymal stem cells prevents tissue damage in collagen-induced arthritis

OBJECTIVE

Mesenchymal stem cells (MSCs) are precursors of tissue of mesenchymal origin, but they also have the capacity to regulate the immune response by suppressing T and B lymphocyte proliferation in a non-major histocompatibility complex-restricted manner. Use of MSCs as immunosuppressant agents in autoimmune diseases has been proposed and successfully tested in animal models. We explored the feasibility of using allogeneic MSCs as therapy for collagen-induced arthritis, a mouse model for human rheumatoid arthritis.

METHODS

DBA/1 mice were immunized with type II collagen in Freund's complete adjuvant, and some of the animals received an intraperitoneal injection of allogeneic MSCs.

RESULTS

A single injection of MSCs prevented the occurrence of severe, irreversible damage to bone and cartilage. MSCs induced hyporesponsiveness of T lymphocytes as evidenced by a reduction in active proliferation, and modulated the expression of inflammatory cytokines. In particular, the serum concentration of tumor necrosis factor alpha was significantly decreased. MSCs exerted their immunomodulatory function by educating antigen-specific Tregs.

CONCLUSION

Our results suggest an effective new therapeutic approach to target the pathogenic mechanism of autoimmune arthritis using allogeneic MSCs. However, further studies are required before these results can be translated to clinical settings.

Murine bone marrow stromal progenitor cells elicit an in vivo cellular and humoral alloimmune response

Stromal progenitor cells (SPC) exhibit immunosuppressive effects in vitro that have led to speculation regarding their capacity to evade host immune recognition and to treat autoimmune diseases and gravt-versus-host disease. However, there is little in vivo experimental data to support these immunologic claims. To assess immune recognition of SPC in vivo, we evaluated the immune response of animals transplanted with SPC. C57BL/6 (B6) or Balb/c adult, murine, bone marrow-derived SPC (AmSPC) were administered by intraperitoneal injection into B6 recipients. T cell proliferation and alloantibody response was assessed from spleens and peripheral blood harvested from transplanted animals and analyzed by cell proliferation assay and flow cytometry. To assess tolerance induction, transplanted animals also received allogeneic skin grafts. Animals injected with allogeneic AmSPC mounted an accelerated CD4 response to alloantigen compared to syngeneic AmSPC injected and uninjected controls. Allogeneic AmSPC-injected animals also demonstrated high titers (> or =1:1000) of antibody directed against allogeneic AmSPC targets. Animals primed with donor or host-matched AmSPC also failed to induce tolerance, and all animals exhibited rejection of allogeneic skin grafts (n = 7, P < .0001). In contrast to their in vitro behavior, our data demonstrate that AmSPC are recognized by the host immune system in vivo, elicit a cellular and humoral immune response, and fail to induce tolerance. These findings have significant implications for all allogeneic SPC-based therapeutic strategies.

Cord blood mesenchymal stem cells: Potential use in neurological disorders

Our previous studies demonstrate enhanced neural protective effects of cord blood (CB) cells in comparison to stem cells from adult marrow. To determine further whether mesenchymal stem cells (MSCs) derived from human umbilical cord blood (hUCB) possess optimal characteristics for neural therapy, we isolated populations of plastic-adherent CB MSCs. These cells generated CD34-, CD45-, CD11b-, CD3-, CD19- cells in culture and failed to produce CFU-M, CFU-GEMM, or CFU-GM hematopoietic colonies in methylcellulose. However, cultured CB MSCs possessed a remarkable ability to support proliferation as well as differentiation of hematopoietic cells in vitro. In addition, supernatants from cultured CB MSCs promoted survival of NT2 N neural cells and peripheral blood mononuclear cells (MNCs) cultured under conditions designed to induce cell stress and limit protein synthesis. After incubation in neural differentiation medium, CB MSCs expressed the neural cell-surface antigen A2B5, the neurofilament polypeptide NF200, the oligodendrocyte precursor marker 04, intermediate filament proteins characteristic of neural differentiation (nestin and vimentin), as well as the astrocyte marker glial fibrillary acidic protein (GFAP) and the neural progenitor marker TUJ-1. We examined the immunomodulatory effects of the CB MSCs after co-culture with murine splenocytes. Whereas spleen cells from normal C57Bl/6 mice exhibited a prominent immunoglobulin M (IgM) response after immunization with the T cell-dependent antigen sheep red blood cells, this response was significantly decreased after incubation with CB MSCs. These data indicate that CB MSCs possess multiple utilities that may contribute to their therapeutic potency in the treatment of neurological disorders.

Sarcoma derived from cultured mesenchymal stem cells

To study the biodistribution of MSCs, we labeled adult murine C57BL/6 MSCs with firefly luciferase and DsRed2 fluorescent protein using nonviral Sleeping Beauty transposons and coinfused labeled MSCs with bone marrow into irradiated allogeneic recipients. Using in vivo whole-body imaging, luciferase signals were shown to be increased between weeks 3 and 12. Unexpectedly, some mice with the highest luciferase signals died and all surviving mice developed foci of sarcoma in their lungs. Two mice also developed sarcomas in their extremities. Common cytogenetic abnormalities were identified in tumor cells isolated from different animals. Original MSC cultures not labeled with transposons, as well as independently isolated cultured MSCs, were found to be cytogenetically abnormal. Moreover, primary MSCs derived from the bone marrow of both BALB/c and C57BL/6 mice showed cytogenetic aberrations after several passages in vitro, showing that transformation was not a strain-specific nor rare event. Clonal evolution was observed in vivo, suggesting that the critical transformation event(s) occurred before infusion. Mapping of the transposition insertion sites did not identify an obvious transposon-related genetic abnormality, and p53 was not overexpressed. Infusion of MSC-derived sarcoma cells resulted in malignant lesions in secondary recipients. This new sarcoma cell line, S1, is unique in having a cytogenetic profile similar to human sarcoma and contains bioluminescent and fluorescent genes, making it useful for investigations of cellular biodistribution and tumor response to therapy in vivo. More importantly, our study indicates that sarcoma can evolve from MSC cultures.

Umbilical cord blood-derived stem cells and brain repair

Human umbilical cord blood (HUCB) is now considered a valuable source for stem cell-based therapies. HUCB cells are enriched for stem cells that have the potential to initiate and maintain tissue repair. This potential is especially attractive in neural diseases for which no current cure is available. Furthermore, HUCB cells are easily available and less immunogenic compared to other sources for stem cell therapy such as bone marrow. Accordingly, the number of cord blood transplants has doubled in the last year alone, especially in the pediatric population. The therapeutic potential of HUCB cells may be attributed to inherent ability of stem cell populations to replace damaged tissues. Alternatively, various cell types within the graft may promote neural repair by delivering neural protection and secretion of neurotrophic factors. In this review, we evaluate the preclinical studies in which HUCB was applied for treatment of neurodegenerative diseases and for traumatic and ischemic brain damage. We discuss how transplantation of HUCB cells affects these disorders and we present recent clinical studies with promising outcome.

Immunological tolerance and autoimmunity

Immunological tolerance is a complex series of mechanisms that impair the immune system to mount responses against self antigens. Central tolerance occurs when immature lymphocytes encounter self antigens in the primary lymphoid organs, and consequently they die or become unreactive. Peripheral tolerance occurs when mature lymphocytes, escaped from negative selection during ontogeny, encounter self antigens in secondary lymphoid organs and undergo anergy, deletion or suppression. A heterogeneous family of T regulatory cells has recently been identified, which have been found to play an important role in suppressing immune responses against self. Failure or breakdown of immunological tolerance results in autoimmunity and autoimmune diseases. Such events are related to both genetic and environmental factors, the latter being mainly represented by infections. Infectious agents can indeed promote autoimmune responses either by inducing tissue inflammation and therefore an unintended bystander activation of autoreactive T cells, or by promoting T cell responses to microbial epitopes that cross react against self peptides.

Regenerating the heart

Cell-based cardiac repair offers the promise of rebuilding the injured heart from its component parts. Work began with committed cells such as skeletal myoblasts, but recently the field has expanded to explore an array of cell types, including bone marrow cells, endothelial progenitors, mesenchymal stem cells, resident cardiac stem cells, and both mouse and human embryonic stem cells. A related strategy for cardiac repair involves cell mobilization with factors such as cytokines. Translation of cell-based approaches to the clinic has progressed rapidly, and clinical trials using autologous skeletal myoblasts and bone marrow cells are under way. Many challenges remain before the vision of healing an infarct by muscle regeneration can be realized. Future research is likely to focus on improving our ability to guide the differentiation of stem cells, control their survival and proliferation, identify factors that mediate their homing and modulate the heart's innate inflammatory and fibrotic responses.

Cytotoxicity of rat marrow stromal cells against malignant glioma cells

OBJECTS

Marrow stromal cells (MSCs) have been shown to have the capacity of orthodox and unorthodox plasticity. In this study, the authors tried to access in vitro cytotoxicity of MSCs from rat and also to differentiate MSCs into immune effector cell.

METHODS

Rat MSCs (rMSCs) were isolated by standard methodology and were activated by interleukin-2 (IL-2), interleukin-15 (IL-15), granulocyte macrophage colony stimulating factor, and combinations, which were effector cells. Cytotoxicity of rMSCs and activated rMSCs against the target cells (9L rat glioma cell line) was estimated using visual survival cell assay. Phenotypes of these various activated cells were determined using flow cytometry. The secreted protein from effector cells was estimated by enzyme-linked immunosorbent assay. The expression of immune response-related genes in activated cells was measured.

RESULTS

There was a significant cytotoxicity of rMSCs activated with various cytokine combinations. After various cytokine activations of rMSCs, the population of immune effector cells (CD8, CD161a) and immune reaction-related proteins (IL-4, gamma-INF) might increase. Apoptosis may be one of the lysis mechanisms of target cells by activated rMSCs. The contributing genes could be gamma-INF, FasL, and perforin.

CONCLUSION

This study suggests that rMSC may be used as adoptive transfer therapy in patients suffering from malignant brain tumor, but we have to investigate orthotopic animal study for the proper translation.