Synergistic effects of mesenchymal stem cell-derived extracellular vesicles and dexamethasone on macrophage polarization under inflammatory conditions.

The undesirable inflammation and the excessive M1 macrophage activity may lead to inflammatory diseases. Corticosteroids and stem cell therapy are used in clinical practice to promote anti-inflammatory responses. However, this protocol has limitations and is associated with numerous side effects. In this study, the synergistic anti-inflammatory effects of dexamethasone (Dex) and mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) were evaluated to enhance the polarization of M1 inflammatory macrophages into the anti-inflammatory (M2) phenotype. Hence, we designed different combinations of Dex and EVs using three methods, including EVs isolated from Dex-preconditioned MSCs (Pre-Dex-EVs), EVs loaded with Dex (L-Dex-EVs), and EVs and Dex co-administration (Dex + EVs). All designed EVs had a significant effect on reducing the expression of M1-related genes (iNOS, Stat1, and IRF5), cytokines (IL6 and TNF-a), and CD markers (CD86) in lipopolysaccharide-stimulated macrophages. On the other hand, these combinations promoted the expression of alternative-activated M2-related genes (Arg-1, Stat6, and IRF4), cytokine (IL10), and CD markers (CD206).The combination of Dex and MSC-EVs enhances the effectiveness of both and synergistically promotes the conversion of inflammatory macrophages into an anti-inflammatory state.

Mesenchymal stem cell-derived extracellular vesicles conditionally ameliorate bone marrow failure symptoms in an immune-mediated aplastic anemia mouse model.

Acquired forms of Aplastic anemia (AA) are characterized by T cell-mediated immune disease resulting in bone marrow (BM) failure and marrow hypoplasia. In these cases, it is a major challenge to modulate autoreactive T cell activity and thereby decrease the pro-inflammatory cytokine storm. Emerging evidence indicates that extracellular vesicles derived from mesenchymal stem cells (MSC-EVs) control and modulate immunity. The therapeutic potential of MSC-EVs has not been investigated in acquired AA. Hence, in this study, we constructed an AA mice model through irradiation and splenocyte infusion to test the benefits of hypoxic MSC-EVs (Hx-EVs) and normoxic MSC-EVs (Nx-EVs). We found that MSC-EVs treatment significantly prolonged the survival rate and increased the platelet (PLT) counts of the AA mice. Immunohistochemical staining and colony assay confirmed amelioration of hypoplasia in the BM and increased numbers of hematopoietic stem cells (HSCs). These effects of MSC-EVs were mediated by T cell suppression and inhibition of interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) production in the AA mouse model. In addition, an in vitro study revealed that MSC-EVs led to reduced IFN-γ and TNF-α levels and there was an association with decreased splenocyte viability. Previous studies examined the diagnostic and prognostic values of microRNAs (miRNAs) in AA and identified miR-199a, miR-146a, miR-223, and miR-126. We used quantitative real-time PCR to evaluate the expression of these miRNAs on isolated BM mononuclear cells (BM-MNCs) from treated and untreated AA mice. miR-223, miR-146a, and miR-199a expressions increased in the MSC-EVs treated AA mice. Treatment with MSC-EVs increased expression of miR-223 and miR-146a. Our findings showed that treatment with MSC-EVs significantly ameliorated immune destruction of HSCs in the AA mouse model and confirmed the importance of miRNAs in the clinical status of this model.

Mesenchymal stem cells support delivery and boost the efficacy of oncolytic reoviruses in TC-1 tumor cells.

Cancer has remained a major health problem around the world. Mesenchymal stem cells (MSCs)-based therapy exhibits a therapeutic effect via different mechanisms. By using MSCs as carrier cells, the major problem of clearance of oncolytic viruses is resolved by neutralizing antibodies before they react with cancer cells. The aim of this study was to characterize the effect of infected MSCs by reovirus type-3 Dearing (T3D) for in vitro cancer therapy. Adipose-derived MSCs (AD-MSCs) were infected with reovirus T3D and its biological properties were evaluated. Then, the effects of reovirus-infected AD-MSCs on cytokine profile, nitric oxide (NO) production, and apoptosis induction in TC-1 cells were assessed. Our results indicated that the differentiation potential of AD-MSCs was affected by reovirus. However, phenotypes were not affected after infection. Then, the effects of reovirus-infected AD-MSCs in TC-1 cells showed an increased amount of tumor necrosis factor-alpha (TNF-α) and NO production and a decreased amount of transforming growth factor-beta 1 (TGF-ß1) and interleukin-10 (IL-10). Moreover, apoptosis significantly increased via coculturing of TC-1 cells with infected AD-MSCs, compared with control, and both internal and external apoptosis pathways are activated in experimental groups. In conclusion, the data showed that with increasing TNF-α and NO production and reducing IL-10 and TGF-ß production, AD-MSCs can enhance the oncolytic effect of reovirus in cancer cells. Furthermore, the results suggested that AD-MSCs can be used as effective carrier cells candidate for reovirus T3D to maximize their anticancer cell activity.

In vitro and in vivo evaluation of anti-tumoral effect of M1 phenotype induction in macrophages by miR-130 and miR-33 containing exosomes.

In the tumor microenvironment, macrophages polarize into the M2 phenotype to facilitate tumorigenesis. Tumor-derived exosomes can act as mediators between the tumor microenvironment and stromal cells by transporting proteins, mRNAs, and miRNAs. Exosomal miRNAs play a pivotal role in modulating tumor microenvironment and macrophage polarization. Here, we overexpressed miR-130 and miR-33 in exosomes of MDA-MB-231 cells and investigated their effect on macrophage polarization and tumor progression. For this purpose, exosomes were extracted from MDA-MB-231 cells and characterized using dynamic light scattering, electron microscopy, and western blotting of exosomal markers. Then, miR-130 or miR-33 containing exosomes were used to treat IL4-induced M2 or tumor-associated macrophages (TAMs). After treatment, the polarization status of macrophages, including the expression of M1 specific genes, and the secretion of cytokines were evaluated. Finally, the conditioned medium from exosome-treated macrophages was incubated with cancer cells to evaluate its effect on the migration and invasion ability of cancer cells and, in vivo experiments investigated the effect of exosome-treated macrophages on breast cancer progression. Exosomes characterization results approved the range of size and homogeneity of extracted exosomes. Overexpression of miR-130 and miR-33 in exosomes increased the expression of M1 signature genes (IRF5, MCP1, CD80) and secretion of cytokines (IL-1ß and TNF-α) as well as yeast phagocytic activity of macrophages. Besides, the conditioned medium of macrophages treated with miRNA containing exosomes declined the migration and invasion ability of cancer cells. The in vivo results indicated the inhibitory effect of exosome-treated macrophages on tumor growth. Furthermore, the results showed that in response to exosome-treated macrophages, the production of TNF-α by spleen cells increased, while the production of IL-10 and TGF-ß by these cells decreased. These findings suggest that overexpression of miR-130 and miR-33 in exosomes can decrease tumor progression by shifting macrophage polarization from M2 to M1 phenotype and can be a potential therapeutic strategy for tumor interventions.

MSCs loaded with oncolytic reovirus: migration and in vivo virus delivery potential for evaluating anti-cancer effect in tumor-bearing C57BL/6 mice.

BACKGROUND AND AIMS: Several oncolytic viruses applications have been approved in the clinic or in different phases of clinical trials. However, these methods have some rudimentary problems. Therefore, to enhance the delivery and quality of treatment, considering the advantage of cell carrier-based methods such as Mesenchymal Stem Cells (MSC) have been proposed. This study was designed to evaluate the performance and quality of cancer treatment based on MSCs loaded by oncolytic reovirus in the cancerous C57BL/6 mouse model. Also, we evaluated MSCs migration potency in vitro and in vivo following the oncolytic reovirus infection. METHODS: C57BL/6 mice were inoculated with TC-1 cell lines and tumors were established in the right flank. Mice were systemically treated with reovirus, MSCs-loaded with reovirus, MSCs, and PBS as a control in separated groups. Effects of infected AD-MSCs with reovirus on tumor growth and penetration in the tumor site were monitored. All groups of mice were monitored for two months in order to therapeutic and anticancer potential. After treatments, tumor size alteration and apoptosis rate, as well as cytokine release pattern was assessed. RESULTS: The results of the current study indicated that the effect of reovirus infection on AD-MSCs is not devastating the migration capacity especially in MOI 1 and 5 while intact cells remain. On the other hand, MSCs play an efficient role as a carrier to deliver oncolytic virus into the tumor site in comparison with systemic administration of reovirus alone. Apoptosis intensity relies on viral titration and passing time. Followed by systemic administration, treatment with oncolytic reovirus-infected AD-MSCs and MSCs alone had shown significant inhibition in tumor growth. Also, treatment by reovirus causes an increase in IFN-γ secretion. CONCLUSION: The results of in vitro and in vivo study confirmed the tumor-homing properties of infected AD-MSCs and the significant antitumor activity of this platform. Hence, our results showed that the cell carrier strategy using oncolytic reovirus-loaded AD-MSCs enhanced virus delivery, infiltration, and antitumor activity can be effectively applied in most cancers.

Vibrio cholerae toxin coregulated pilus provokes inflammatory responses in Coculture model of Caco-2 and peripheral blood mononuclear cells (PBMC) leading to increased colonization.

The aim of this study was to assess the modulatory effect of TcpA in the expression of CEACAM1 adhesin molecule and IL-1, IL-8, and TNF-α pro-inflammatory cytokines in the Coculture model of Caco-2/PBMC (peripheral blood mononuclear cell) that can mimic the intestinal milieu. The TcpA gene from Vibrio cholerae ATCC14035 was cloned in pET-28a and transformed into Escherichia coli Bl-21. The recombinant TcpA-His6 protein was expressed and purified using Ni-column chromatography. The sequencing of transformed plasmid and Western blot analysis of purified protein confirmed the identity of rTcp. The cytotoxicity of different concentrations of recombinant protein for human colon carcinoma cell line (human colorectal adenocarcinoma cell [Caco-2 cell]) was assessed by MTT assay and showed viability of 92%, 82%, and 70%, for 10 µg/mL of TcpA after 24, 48, and 72 h, respectively. Co-cultures of Caco-2 and PBMCs were used to mimic the intestinal milieu and treated with different concentrations of rTcpA (1, 5, 10, and 50 µg/mL). Our data showed about 2.04-, 3.37-, 3.68-, and 42.7-fold increase in CEACAM1 gene expression, respectively, compared with the nontreated Caco-2/PBMC Coculture. Moreover, the expression of IL-1, IL-8, and TNF-α genes was significantly increased up to 15.75-, 7.04-, and 80.95-folds, respectively. In conclusion, V. cholerae TcpA induces statistically significant dose-dependent stimulatory effect on TNF-α, IL-,1, and IL-8 pro-inflammatory cytokines expression. Of these, TNF-α was much more affected which, consequently, elevated the CEACAM1 expression level in IECs. This suggests that TcpA protein is a critical effector as an inducer of increased adhesion potential of V. cholera as well as inflammatory responses of host intestinal tissue.

Unfolded protein response-mediated modulation of mesenchymal stem cells.

The endoplasmic reticulum (ER) receives unfolded proteins predestined for the secretory pathway or to be incorporated as transmembrane proteins. The ER has to accommodate the proper folding and glycosylation of these proteins and also to properly incorporate transmembrane proteins. However, under various circumstances, the proteins shuttling through the ER can be misfolded and undergo aggregation, which causes activation of the unfolded protein response (UPR). The UPR is mediated through three primary pathways: activating transcription factor-6, inositol-requiring enzyme-1 (IRE1), and PKR-like endoplasmic reticulum kinase, which up-regulate ER folding chaperones and temporarily suppress protein translation. The UPR can be both cytoprotective and/or cytotoxic depending on the duration of UPR activation and the type of host cell. Proteostasis controls stem cell function, while stress responses affect stem cell identity and differentiation. The present review aimed to explore and discuss the effects of the UPR pathways on mesenchymal stem cells.

Modulatory effect of Vibrio cholerae toxin co-regulated pilus on mucins, toll-like receptors and NOD genes expression in co-culture model of Caco-2 and peripheral blood mononuclear cells (PBMC).

Vibrio cholerae, the causative agent of cholera, tend to colonize the small intestine as a Gram-negative pathogen. The intestinal mucus layer forms mucin physical barrier, consisted of high molecular weight proteins. Regarding the role of toxin-coregulated pilus (TCP) as one of the most important colonization factors of V. cholerae, this experimental study was designed to determine the role of TcpA in induction of mucin production and its regulatory effect on innate immunity molecules including toll like receptors (TLRs) and Nucleotide-binding oligomerization domain-containing proteins (NODs) using Caco2- PBMC co-cultures as an interactive model. The rTcpA protein of V. cholerae was expressed in BL21 Escherichia coli, purified using Ni-column chromatography and confirmed by western blotting. Nontoxic doses of rTcpA was determined on Caco-2 cell lines and different concentrations of rTcpA (1, 5, 10 and 50 µg/mL) showed a statistically significant effect on the expression of muc genes (MUC3 and MUC4) in a dose-dependent manner. This finding is supposed to facilitate physical adhesion and colonization of V. cholerae in intestinal lumen. The rTcpA moderately stimulated the expression of tlr4 and overexpressed tlr1, both of which are supposed to induce a mucosal protective response against bacterial infection. NOD2 was significantly increased which suggests that it may contribute in pro-inflammatory responses observed in cholera disease. No change in NOD1 expression was seen which might be attributed to the non-invasive nature of V. cholerae as an intestinal pathogen. In conclusion, the rTcpA protein of V. cholerae showed a statistically significant modulatory effect on the human gut epithelium gene expression which would help promising protection in prophylaxis applications.

Antibacterial and antibiofilm activity of bone marrow-derived human mesenchymal stem cells secretome against Vibrio cholerae.

The ability of V. cholerae to survive and spread in the aquatic environment combined with the scarcity of effective antimicrobial agents, especially those effective against multidrug-resistant strains highlights the need for alternative non-antibiotic approaches for the treatment of V. cholerae infections. The aim of this study was to specifically examine the potential direct effect of unstimulated MSC secretome on V. cholerae killing and biofilm formation as a representative of non-invasive enteric bacterial pathogen. The bmMSCs were characterized by the presence of CD44 and CD73 and the absence of CD45 and CD34 molecular markers. Moreover, self-regeneration and differentiation capacity of MSCs into adipocytes and osteogenic lineages was assessed by immunohistology (IHC) method. The antibacterial activity of unstimulated MSCs supernatant against V. cholerae in broth microdilution assay decreased the bacterial suspension from 108 CFU/ml to 107 CFU/ml and showed a significant antimicrobial activity in a dose-dependent manner at dilutions of 1:8 to 1:128 (P < 0.05). The role of MSC secretome without preconditioning in the prevention of biofilm formation was assessed through plate-crystal violet assay and showed high antibiofilm activity against V. cholerae also in dose-dependent manner. As antibacterial mechanisms of MSC secretome are different from conventional antibiotics, together with its antibiofilm activity, proposes its application as a novel therapeutic approach combatting multi-drug resistant pathogens with no fear of developing antimicrobial resistance.

Investigating the route of administration and efficacy of adipose tissue-derived mesenchymal stem cells and conditioned medium in type 1 diabetic mice.

Type 1 diabetes (T1D) is a chronic autoimmune disease destroying the insulin-producing beta cells. Recently, stem cell therapy has been tested to treat T1D. In the present study, we aim to investigate the effects of intraperitoneal and intravenous infusion of multipotent mesenchymal stem/stromal cells (MSCs) and MSC-conditioned medium (MSC-CM) in an experimental model of diabetes, induced by multiple injections of Streptozotocin (STZ). The adipose tissue-derived MSC and MSC-CM were isolated from C57Bl/6 male mice and characterized. Later, MSC and MSC-CM were injected intraperitoneally or intravenously into mice. The blood glucose, urinary glucose, and body weight were measured, and the percentages of CD4+ CD25+ FOXP3+ T cells as well as the levels of IFN-γ, TGF-ß, IL-4, IL-17, and IL-10 were evaluated. Our results showed that both intraperitoneal and intravenous infusions of MSC and MSC-CM could decrease the blood glucose, recover pancreatic islets, and increase the levels of insulin-producing cells. Furthermore, the percentage of CD4+ CD25+ FOXP3+ T cells was increased after intraperitoneal injection of MSC or MSC-CM and intravenous injection of MSCs. After intraperitoneal injection of the MSC and MSC-CM, the levels of inflammatory cytokines reduced, while the levels of anti-inflammatory cytokines increased. Together current data showed that although both intraperitoneal and intravenous administration had beneficial effects on T1D animal model, but intraperitoneal injection of AD-MSC and AD-MSC-CM was more effective than systemic administration.

Tumor-derived exosomal microRNAs and proteins as modulators of macrophage function.

Tumor cells are able to modify their surrounding microenvironment by transmitting bioactive molecules via exosomes. In exosomes, proteins and nucleic acids that can be taken up by surrounding cells have been identified and modulate their functions. Tumor microenvironment consists of different cells such as macrophages. Tumors-associated macrophages (TAMs) express M2 phenotype and affect many processes including tumor initiation, angiogenesis, and metastasis. It has been demonstrated that a high number of TAMs is associated with poor prognosis of cancers. The contents of tumor-derived exosomes such as microRNAs and proteins induce macrophages to M2-like polarization to support tumor growth. Herein, we review the most recent studies on the effect of tumor-derived exosomes on macrophage polarization and function in different types of cancers.

A simple and highly efficient method for transduction of human adipose-derived mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are multipotent cells capable of differentiating into a wide range of cell types and provide a potential to transfer therapeutic protein in vivo, making them valuable candidates for gene therapy and cell therapy. However, using MSCs in in vivo is limited due to the low rate of transfection and transduction efficacy. Therefore, developing methods to efficiently transfer genes into MSCs would provide a number of opportunities for using them in the clinic. Here, we introduce a simple and robust method for efficient transduction of human adipose-derived MSCs by modification under the culture condition of human embryonic kidney cells 293 (HEK293T) and MSCs. Moreover, as a transduction enhancer, polybrene was replaced with Lipofectamine, a cationic lipid. Therefore, we showed that transduction of primary cells can be increased efficiently by modifying the culture condition.

Immunomodulatory effects of mesenchymal stem cell-derived exosomes on experimental type-1 autoimmune diabetes.

Exosomes derived from adipose tissue-derived mesenchymal stem cells (AD-MSCs) have immunomodulatory effects of T-cell inflammatory response and reduction of clinical symptoms on streptozotocin-induced of the type-1 diabetes mellitus (T1DM). Beside control group and untreated T1DM mice, a group of T1DM mice was treated with intraperitoneal injections of characterized exosomes derived from autologous AD-MSCs. Body weight and blood glucose levels were measured during the procedure. Histopathology and immunohistochemistry were used for evaluation of pancreatic islets using hemotoxylin and eosin (H&E) staining and anti-insulin antibody. Isolated splenic mononuclear cells (MNCs) were subjected to splenocytes proliferation assay using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, immunophenotyping of regulatory T cells and cytokines. A significant increase in the levels of interleukin-4 (IL-4), IL-10, and transforming growth factor-ß, and a decrease in the levels of IL-17 and interferon-γ in concordance with the significant increase in the Treg cell ratio in splenic MNCs (P < 0.05) was shown in T1DM mice treated with AD-MSC's exosomes as compared to T1DM untreated mice. This amelioration of autoimmune reaction after treatment of T1DM mice with the AD-MSC exosomes was confirmed with a significant increase in islets using H&E staining and Immunohistochemistry analyses. As expected, body weight, blood glucose levels in a survival of T1DM mice treated with AD-MSC's exosomes were maintained stable in comparison to untreated T1DM mice. It can be concluded that AD-MSC's exosomes exert ameliorative effects on autoimmune T1DM through increasing regulatory T-cell population and their products without a change in the proliferation index of lymphocytes, which makes them more effective and practical candidates.

Pretreatment of Mesenchymal Stem Cells With Leishmania major Soluble Antigens Induce Anti-Inflammatory Properties in Mouse Peritoneal Macrophages.

Recent studies have demonstrated the influential role of microbial stimulus in characteristics and immunomodulatory effects of mesenchymal stem cells (MSCs). Due to the migration of MSCs to infection site, it is of importance to understand the interaction of microbial ligands with MSCs in order to clarify the positive or negative role of MSCs in the control of infection. In this research, we assess leishmanial soluble antigen (LSA)-primed MSCs on macrophage immune responses to lipopolysaccharide (LPS). For this purpose, the effects of both conditioned media (CM) and cell-cell contact of LSA primed MSCs were determined on macrophage responses to LPS. According to the obtained results, MSC-treated macrophages demonstrated an alternatively activated macrophages with higher levels of interleukin-10 (IL-10) and transforming growth factor-alpha (TNF-α) and lower levels of IL-6 and nitric oxide (NO) production as compared to the controls. In addition, phagocytosis of apoptotic thymocytes was induced in MSC-treated macrophages. In conclusion, it seems that MSCs trigger an anti-inflammatory phenotype in macrophages at Leishmania infected sites in order to enhance the induction of immune regulatory cells and clearance of apoptotic cells. J. Cell. Biochem. 118: 2764-2779, 2017. © 2017 Wiley Periodicals, Inc.

Secretome of adipose derived-mesenchymal stem cells reduces the Vibrio cholerae attachment to Caco-2 cells and subsequent inflammatory responses.

Background and Objectives: Mesenchymal Stem Cells (MSCs) can repair gastrointestinal tract damage. The Secretome of MSCs has a high capacity to inhibit bacterial colonization and the subsequent inflammatory responses of Vibrio cholerae. Materials and Methods: The Caco-2 cells were treated with adipose-derived MSCs (AD-MSCs) secretome and then infected with V. cholerae. Subsequently, the bacterial attachment and invasion, cholera toxin gene expression, PGE2 and IL-6 secretion, TNF-α, IL-1ß, and IL-8 expression, and apoptosis of Caco-2 cells were evaluated. Results: The secretome of AD-MSCs significantly reduced the V. cholerae attachment and internalization on Caco-2 epithelial cells (P<0.0001). The cholera toxin (Ctx-B) gene expression (FR=4.56 ± 0.66) and PGE2 production (P=0.0007) were also significantly reduced. The production of NO and TNF-α, IL-1ß, and IL-8 pro-inflammatory cytokines were significantly (P<0.05) reduced in exposure to the secretome of AD-MSCs. Secretome also improved a significant 81.33% increase in IL-6 production (128.1 ± 37.6 pg/mL) and showed a 12.36% significant decrease in epithelial cell apoptosis (P< 0.0001) after exposure to V. cholerae. Conclusion: The secretome of AD-MSCs can play a critical role in inhibiting bacterial colonization, and subsequent inflammatory responses, and maintaining the integrity of the epithelial barrier. The secretome may be effective in the prevention of hypovolemic shock.

Mesenchymal stem cell-conditioned medium prevents inflammation-induced liver and lung damage in septic mice.

AIM: Sepsis is a life-threatening condition caused by a dysregulated immune response to infection. Broad-spectrum antibiotics are used to treat it. However, due to antibiotic resistance, alternative treatments are needed. Mesenchymal stem cells (MSCs) have become a promising therapeutic tool for sepsis due to their immunomodulatory properties. The limitations of MSC therapy have led to increased attention to cell derivatives such as conditioned medium (CM). This study investigates the immunomodulatory effects of young and old MSC-CM during the inflammatory phase of sepsis. MAIN METHODS: The cecal ligation and puncture (CLP) model was used to induce sepsis in mice. The mice were divided into four groups: sham, CLP, CLP treated with young MSC-CM, and CLP treated with old MSC-CM. The CM was injected intraperitoneally at 2-, 12-, and 24-hours post-surgery. After 72 h, blood was collected and white blood cells (WBCs) were counted. In addition, serum and tissue were isolated, and the levels of alanine transaminase (ALT) and aspartate transaminase (AST) in serum, bacterial load in the spleen, concentration of pro- and anti-inflammatory cytokines, and histopathology of liver and lung were investigated. KEY FINDINGS: MSC-CM decreased serum AST and ALT levels, bacterial load in the spleen, and pro-inflammatory cytokines in serum. In addition, tissue damage was reduced, and the survival rate and WBC count increased. There was no significant difference between the young and old MSC-CM. SIGNIFICANCE: MSC-CM effectively reduced inflammation-induced tissue damage in the liver and lungs during sepsis. Although young MSC-CM had better immunomodulatory effects than old MSC-CM, the difference was not significant.

Intra-abdominal transplantation of PLGA/PCL/M13 phage electrospun scaffold induces self-assembly of lymphoid tissue-like structure.

Lymphoid organs are the main structural components of the immune system. In the current research, the mixture of poly lactic-co-glycolic acid (PLGA), polycaprolactone (PCL), and M13 phage or its RGD-modified form was used in the construction of a fibrillar scaffold using the electrospinning method. The constructs were transplanted intra-abdominally and examined for the formation of lymphoid-like tissues at different time intervals. The confocal and scanning electron microscopy demonstrate that M13 phage-containing scaffolds provide a suitable environment for lymph node-isolated fibroblasts. Morphological analysis demonstrate the formation of lymph node-like tissues in the M13 phage-containing scaffolds after transplantation. Histological analysis confirm both blood and lymph angiogenesis in the implanted construct and migration of inflammatory cells to the M13 phage-containing scaffolds. In addition, flow cytometry and immunohistochemistry analysis showed the homing and compartmentalization of dendritic cells (DCs), B and T lymphocytes within the PLGA/PCL/M13 phage-RGD based scaffolds and similar to what is seen in the mouse lymphoid tissues. It seems that the application of M13 phage could improve the generation of functional lymphoid tissues in the electrospun scaffolds and could be used for lymphoid tissue regeneration.

Comparative immunomodulatory properties of adipose-derived mesenchymal stem cells conditioned media from BALB/c, C57BL/6, and DBA mouse strains.

Adipose tissue-derived mesenchymal stem cells (AD-MSCs) have been shown to be capable of differentiating into multiple cell type and exert immunomodulatory effects. Since the selection of ideal stem cell is apparently crucial for the outcome of experimental stem cell therapies, therefore, in this study we compared AD-MSCs conditioned media (CM) from BALB/c, C57BL/6, and DBA mouse strains. No significant difference was found in the morphology, cell surface markers, in vitro differentiation and proliferation potentials of AD-MSCs isolated from C57BL/6, BALB/c, and DBA mice. The immunological assays showed some variation among the strains in the cytokines, nitric oxide (NO), and indoleamine 2,3-dioxygenase (IDO) production and immunomodulatory effects on splenocytes functions. Our results indicated a suppression of splenocytes proliferation in the presence of AD-MSC CM from the three inbred mouse strains. However, BALB/c CM exerted a higher suppression of splenocytes proliferation. AD-MSCs isolated from C57BL/6 and BALB/c mice produced higher levels of TGF-ß than those from DBA mice. Furthermore, IL-17 and IDO production was higher in AD-MSCs isolated from BALB/c mice. Our results indicated an increased production of TGF-ß, IL-4, IL-10, NO, and IDO by splenocytes in response to CM from BALB/c AD-MSCs. In conclusion, our results showed that the immunomodulatory properties of mouse AD-MSCs is strain-dependent and this variation should be considered during selection of appropriate stem cell source for in vivo experiments and stem cell therapy strategies.

In vitro immunomodulatory properties of osteogenic and adipogenic differentiated mesenchymal stem cells isolated from three inbred mouse strains.

Mesenchymal stem cells (MSCs) are used for cell-based therapies because of their immunomodulatory properties. The immunomodulatory properties of adipogenic (AD) and osteogenic (OS) differentiated adipose tissue-derived MSCs (AD-MSCs) isolated from BALB/c, C57BL/6, and DBA mice were compared. Splenocytes proliferation was suppressed in the presence of AD-MSCs conditioned media in all mice. After OS differentiation, BALB/c AD-MSCs produced higher levels of TGF-ß and IL-17 and lower levels of NO than AD-MSCs isolated from C57BL/6 and DBA mice. In addition, OS differentiated AD-MSCs isolated from DBA mice produced lower levels of IL-10 than AD-MSCs isolated from C57BL/6 and DBA mice. After in vitro AD and OD differentiation, AD-MSCs isolated from each mouse produced higher levels of NO and IDO than undifferentiated cells. Additionally, AD-MSCs isolated from C57BL/6 and DBA mice produced higher levels of NO than AD-MSCs isolated from BALB/c mice. Adipose tissue-derived MSCs thus retain their immunomodulatory properties after in vitro OS and AD differentiation in a strain-dependent manner.