IL-27 Promotes Human Placenta-Derived Mesenchymal Stromal Cell Ability To Induce the Generation of CD4+IL-10+IFN-γ+ T Cells via the JAK/STAT Pathway in the Treatment of Experimental Graft-versus-Host Disease

hUCMSC-derived exosomes protect against GVHD-induced endoplasmic reticulum stress in CD4+ T cells by targeting the miR-16-5p/ATF6/CHOP axis

Exosomes generated from mesenchymal stem cells (MSCs) are thought to be a unique therapeutic strategy for several autoimmune deficiency illnesses. The purpose of this study was to elucidate the protective effects of human umbilical cord mesenchymal stem cell-derived exosomes (hUCMSC-Exo) on CD4+ T cells dysfunction during graft-versus-host disease (GVHD) and to identify the underlying processes involved. Here, we showed that hUCMSC-Exo treatment can effectively attenuate GVHD injury by alleviating redox metabolism disorders and inflammatory cytokine bursts in CD4+ T cells. Furthermore, hUCMSC-Exo ameliorate ER stress and ATF6/CHOP signaling-mediated apoptosis in CD4+ T cells and promote the development of CD4+IL-10+ T cells during GVHD. Moreover, downregulating miR-16-5p in hUCMSC-Exo impaired their ability to prevent CD4+ T cells apoptosis and weakened their ability to promote the differentiation of CD4+IL-10+ T cells. Collectively, the obtained data suggested that hUCMSC-Exo suppress ATF6/CHOP signaling-mediated ER stress and apoptosis in CD4+ T cells, enhance the differentiation of CD4+IL-10+ T cells, and reverse the imbalance of immune homeostasis in the GVHD process by transferring miR-16-5p. Our study provided further evidence that GVHD patients can benefit from hUCMSC-Exo-mediated therapy.

Interleukin-27 Promotes the Generation of Myeloid-derived Suppressor Cells to Alleviate Graft-versus-host Disease

BACKGROUND

Stimulation of myeloid-derived suppressor cell (MDSC) formation represents a potential curative therapeutic approach for graft-versus-host disease (GVHD), which significantly impacts the prognosis of allogeneic hematopoietic stem cell transplantation. However, the lack of an effective strategy for inducing MDSC production in vivo has hindered their clinical application. In our previous study, MDSC expansion was observed in interleukin (IL)-27-treated mice.

METHODS

In this study, we overexpressed exogenous IL-27 in mice using a recombinant adeno-associated virus vector to investigate its therapeutic and exacerbating effects in murine GVHD models.

RESULTS

In our study, we demonstrated that exogenous administration of IL-27 significantly suppressed GVHD development in a mouse model. We found that IL-27 treatment indirectly inhibited the proliferation and activation of donor T cells by rapidly expanding recipient and donor myeloid cells, which act as MDSCs after irradiation or under inflammatory conditions, rather than through regulatory T-cell expansion. Additionally, IL-27 stimulated MDSC expansion by enhancing granulocyte-monocyte progenitor generation. Notably, we verified that IL-27 signaling in donor T cells exerted an antagonistic effect on GVHD prevention and treatment. Further investigation revealed that combination therapy involving IL-27 and T-cell depletion exhibited remarkable preventive effects on GVHD in both mouse and xenogeneic GVHD models.

CONCLUSIONS

Collectively, these findings suggest that IL-27 promotes MDSC generation to reduce the incidence of GVHD, whereas targeted activation of IL-27 signaling in myeloid progenitors or its combination with T-cell depletion represents a potential strategy for GVHD therapy.

hPMSCs Regulate the Level of TNF-α and IL-10 in Th1 Cells and Improve Hepatic Injury in a GVHD Mouse Model via CD73/ADO/Fyn/Nrf2 Axis

Mesenchymal stem cells (MSCs) ameliorate graft-versus-host disease (GVHD)-induced tissue damage by exerting immunosuppressive effects. However, the related mechanism remains unclear. Here, we explored the therapeutic effect and mechanism of action of human placental-derived MSCs (hPMSCs) on GVHD-induced mouse liver tissue damage, which shows association with inflammatory responses, fibrosis accompanied by hepatocyte tight junction protein loss, the upregulation of Bax, and the downregulation of Bcl-2. It was observed in GVHD mice and Th1 cell differentiation system that hPMSCs treatment increased IL-10 levels and decreased TNF-α levels in the Th1 subsets via CD73. Moreover, hPMSCs treatment reduced tight junction proteins loss and inhibited hepatocyte apoptosis in the livers of GVHD mice via CD73. ADO level analysis in GVHD mice and the Th1 cell differentiation system showed that hPMSCs could also upregulate ADO levels via CD73. Moreover, hPMSCs enhanced Nrf2 expression and diminished Fyn expression via the CD73/ADO pathway in Th1, TNF-α+, and IL-10+ cells. These results indicated that hPMSCs promoted and inhibited the secretion of IL-10 and TNF-α, respectively, during Th1 cell differentiation through the CD73/ADO/Fyn/Nrf2 axis signaling pathway, thereby alleviating liver tissue injury in GVHD mice.

Human placental mesenchymal stromal cells modulate IFN-γ and IL-10 secretion by CD4+T cells via CD73, and alleviate intestinal damage in mice with graft-versus-host disease

BACKGROUND

Intestinal inflammatory damage is an important factor in the development of graft-versus-host disease (GVHD). IFN-γ and IL-10 play key roles in gastrointestinal inflammation, and human placental mesenchymal stromal cells (hPMSCs) can alleviate inflammatory damage during GVHD. CD73 is highly expressed by hPMSCs. We aimed to study whether hPMSCs could alleviate intestinal damage in GVHD mice by modulating IFN-γ and IL-10 in CD4+T cells by CD73.

METHODS

A GVHD mouse model was induced using 8-week-old C57BL/6J and BALB/c mice, which were treated with regular hPMSCs (hPMSCs) or hPMSCs expressing low level of CD73 (shCD73). Then, the levels of IFN-γ and IL-10 in CD4+T cells were determined using flow cytometry. Transmission electron microscopy, western blotting, and morphological staining were employed to observe the intestinal damage.

RESULTS

hPMSCs ameliorated pathological damage and inhibited the reduction of the tight junction molecules occludin and ZO-1. They also downregulated IFN-γ and upregulated IL-10 secretion in CD4+T cells via CD73. Moreover, IL-10 mitigated the inhibitory effects of IFN-γ on the expression of occludin in both Caco-2 and NCM460 cells in vitro, but did not affect ZO-1. In addition, hPMSCs upregulated the level of AMPK phosphorylation in CD4+T cells by CD73, which is positively associated with the proportion of CD4+IFN-γ+IL-10+T, and CD4+IFN-γ-IL-10+T cells.

CONCLUSIONS

Our findings suggested that hPMSCs may balance the levels of IFN-γ and IL-10 in CD4+T cells by promoting the phosphorylation of AMPK via CD73, which alleviates the loss of occludin and ZO-1 in intestinal epithelial cells and, in turn, reduces inflammatory injury in GVHD mice.

The Clinical Effect and Mechanism of Prostant on Urinary Retention and Anal Pain

Anal pain and urinary retention are the two most outstanding complications of the procedure for prolapse and hemorrhoids (PPH) surgery. This study intended to assess the clinical effect and mechanism of Prostant on urinary retention and anal pain after the PPH. Here, 30 patients received PPH surgery. The role and mechanism of Prostant in patients and mice with urinary retention and anal pain were evaluated. ANOVA tests were executed and differences between groups were regarded as statistically significant when p < 0.05. Prostant effectively improved the urination status, lower abdomen symptoms, time to urinate and score of VAS, and the reduction of TNF-α and IL-6. Similarly, Prostant can ameliorate the outcome of urodynamics in urinary retention mice. Mechanically, Prostant reversed the urinary retention-elevated the serum level of hs-CRP and TNF-α, reduction of IL-2, imbalance of Treg/Th17, and level of JAK2 and phosphorylated STAT3. Besides, Prostant ameliorated the pain as shown by the reduction of writhing response, and the elevation of threshold of pain and degree of swelling. Moreover, Prostant antagonized the pain-induced dysregulation of Treg/Th17. Therefore, Prostant can treat patients and mice with anal pain and urinary retention by modulating the balance of Th17/Treg to regulate the secretion and production of inflammatory factors. We hope our results can establish a scientific treatment approach for solving anal pain and urinary retention after PPH surgery of mixed hemorrhoids.

Dietary Succinoglycan Riclin Improves Glycemia Control in Mice with Type 2 Diabetes

Riclin is a typical succinoglycan produced by an agrobacterium isolate. Our previous investigation has revealed that oral riclin restores the islet function in type 1 diabetic mice. However, whether dietary riclin improves glycemic control in type 2 diabetes (T2D) is unknown. Here, we found that dietary riclin (20 and 40 mg/kg) for 4 weeks significantly decreased fasting blood glucose (55 and 67%), improved insulin sensitivity, and decreased insulin resistance in high-fat-diet/streptozocin (HFD/STZ)-induced T2D. Riclin reduced the proportion of T helper 1 cell subsets in diabetic mice, alleviated pancreatic inflammation, and protected islet function. Moreover, dietary riclin enriched the diversity of gut microflora and restored the relative abundance of several bacterial genera in diabetes, including the strains of Clostridium, Parasutterella, Klebsiella, and Bacteroides. In db/db diabetic mice, riclin also improves glycemia control as observed in HFD/STZ-induced T2D mice. These data suggest that riclin has potential to be a functional food to treat T2D.

Highlighting the interaction between immunomodulatory properties of mesenchymal stem cells and signaling pathways contribute to Graft Versus Host Disease management

Background Allogeneic hematopoietic stem cell transplantation (Allo-HSCT) has been increasingly used as a therapeutic approach for hematological malignancies. Several potential strategies have been developed for treating or preventing allo-HSCT complications, specifically graft-versus-host disease (GVHD). GVHD could significantly affect the morbidity and mortality of patients after allo-HSCT. Curative treatment and prophylaxis regimens for GVHD could reduce GVHD incidence and improve survival rate. Among these therapeutic strategies, mesenchymal stem cell (MSCs) mediated immunomodulation has been explored widely in clinical trials. MSCs immunomodulation ability in GVHD correlates with the interactions of MSCs with innate and adaptive immune cells. However, signaling pathways responsible for MSCs' impact on GVHD regulation, like JAK/STAT, NOTCH, MAPK/ERK, and NFκβ signaling pathways, have not been clearly described yet. This review aims to illuminate the effect of MSCs-mediated immunomodulation in GVHD management after allo-HSCT representing the role of MSCs therapy on signaling pathways in GVHD. Conclusion MSCs could potentially modulate immune responses, prevent GVHD, and improve survival after allo-HSCT. Previous studies have investigated different signaling pathways' contributions to MSCs immunoregulatory ability. Accordingly, targeting signaling pathways components involved in MSCs related GVHD regulation is proven to be beneficial.

IL-27 Mediates PD-L1 Expression and Release by Human Mesothelioma Cells

Malignant mesothelioma (MM) is a rare tumor with an unfavorable prognosis. MM genesis involves asbestos-mediated local inflammation, supported by several cytokines, including IL-6. Recent data showed that targeting PD-1/PD-L1 is an effective therapy in MM. Here, we investigated the effects of IL-6 trans-signaling and the IL-6-related cytokine IL-27 on human MM cells in vitro by Western blot analysis of STAT1/3 phosphorylation. The effects on PD-L1 expression were tested by qRT-PCR and flow-cytometry and the release of soluble (s)PD-L1 by ELISA. We also measured the concentrations of sPD-L1 and, by multiplexed immunoassay, IL-6 and IL-27 in pleural fluids obtained from 77 patients in relation to survival. IL-27 predominantly mediates STAT1 phosphorylation and increases PD-L1 gene and surface protein expression and sPD-L1 release by human MM cells in vitro. IL-6 has limited activity, whereas a sIL-6R/IL-6 chimeric protein mediates trans-signaling predominantly via STAT3 phosphorylation but has no effect on PD-L1 expression and release. IL-6, IL-27, and sPD-L1 are present in pleural fluids and show a negative correlation with overall survival, but only IL-27 shows a moderate albeit significant correlation with sPD-L1 levels. Altogether these data suggest a potential role of IL-27 in PD-L1-driven immune resistance in MM.

hPMSCs inhibit the expression of PD-1 in CD4+IL-10+ T cells and mitigate liver damage in a GVHD mouse model by regulating the crosstalk between Nrf2 and NF-κB signaling pathway

Background

The activation of T cells and imbalanced redox metabolism enhances the development of graft-versus-host disease (GVHD). Human placenta-derived mesenchymal stromal cells (hPMSCs) can improve GVHD through regulating T cell responses. However, whether hPMSCs balance the redox metabolism of CD4⁺IL-10⁺ T cells and liver tissue and alleviate GVHD remains unclear. This study aimed to investigate the effect of hPMSC-mediated treatment of GVHD associated with CD4⁺IL-10⁺ T cell generation via control of redox metabolism and PD-1 expression and whether the Nrf2 and NF-κB signaling pathways were both involved in the process.

Methods

A GVHD mouse model was induced using 6–8-week-old C57BL/6 and Balb/c mice, which were treated with hPMSCs. In order to observe whether hPMSCs affect the generation of CD4⁺IL-10⁺ T cells via control of redox metabolism and PD-1 expression, a CD4⁺IL-10⁺ T cell culture system was induced using human naive CD4⁺ T cells. The percentage of CD4⁺IL-10⁺ T cells and their PD-1 expression levels were determined in vivo and in vitro using flow cytometry, and Nrf2, HO-1, NQO1, GCLC, GCLM, and NF-κB levels were determined by western blotting, qRT-PCR, and immunofluorescence, respectively. Hematoxylin-eosin, Masson’s trichrome, and periodic acid-Schiff staining methods were employed to analyze the changes in hepatic tissue.

Results

A decreased activity of superoxide dismutase (SOD) and a proportion of CD4⁺IL-10⁺ T cells with increased PD-1 expression were observed in GVHD patients and the mouse model. Treatment with hPMSCs increased SOD activity and GCL and GSH levels in the GVHD mouse model. The percentage of CD4⁺IL-10⁺ T cells with decreased PD-1 expression, as well as Nrf2, HO-1, NQO1, GCLC, and GCLM levels, both in the GVHD mouse model and in the process of CD4⁺IL-10⁺ T cell generation, were also increased, but NF-κB phosphorylation and nuclear translocation were inhibited after treatment with hPMSCs, which was accompanied by improvement of hepatic histopathological changes.

Conclusions

The findings suggested that hPMSC-mediated redox metabolism balance and decreased PD-1 expression in CD4⁺IL-10⁺ T cells were achieved by controlling the crosstalk between Nrf2 and NF-κB, which further provided evidence for the application of hPMSC-mediated treatment of GVHD.

Interleukin-27 Inhibits Epithelial-Mesenchymal Transition in Ovalbumin-Induced Mice Bronchial Epithelial Cells

The epithelial-mesenchymal transition (EMT) of bronchial epithelial cells is a critical mechanism involved in transforming growth factor beta 1 (TGF-β1) induced asthma airway remodeling. Previous study has shown that interleukin 27 (IL-27) attenuates EMT in alveolar epithelial cells, but its effects on the BEAS-2B human bronchial epithelial cell line EMT remain unknown. Herein, we explored the effects of IL-27 on BEAS-2B EMT in vivo and in vitro. In the in vivo experiments, we found that IL-27 nose-drip therapy alleviated airway remodeling, increased the epithelial phenotypic marker epithelial-cadherin (E-cadherin), and decreased the mesenchymal phenotypic marker alpha-smooth muscle actin (α-SMA) compared with the asthmatic control group. We also found that IL-27 suppressed the signal transducer and activator of transcription (STAT3) in the lung tissue of asthmatic mice. in vitro, TGF-β1-induced EMT changes, including downregulation of E-cadherin and upregulation of α-SMA, were suppressed by IL-27 treatment. Additionally, STAT3 phosphorylation was activated by TGF-β1, whereas IL-27 inhibited the activation of TGF-β1 induced STAT3 phosphorylation. Our findings indicated that IL-27 could inhibit airway remodeling by attenuating bronchial epithelial cell EMT in vivo and in vitro. Therefore, IL-27 may be a beneficial therapeutic option targeting asthmatic airway remodeling.

Placenta: A gold mine for translational research and regenerative medicine

Stem cell therapy has gained much impetus in regenerative medicine due to some of the encouraging results obtained in the laboratory as well as in translational/clinical studies. Although stem cells are of various types and their therapeutic potential has been documented in several studies, mesenchymal stromal/stem cells (MSCs) have an edge, as in addition to being multipotent, these cells are easy to obtain and expand, pose fewer ethical issues, and possess immense regenerative potential when used in a scientifically correct manner. Currently, MSCs are being sourced from various tissues such as bone marrow, cord, cord blood, adipose tissue, dental tissue, etc., and, quite often, the choice depends on the availability of the source. One such rich source of tissue suitable for obtaining good quality MSCs in large numbers is the placenta obtained in a full-term delivery leading to a healthy child's birth. Several studies have demonstrated the regenerative potential of human placenta-derived MSCs (hPMSC), and most show that these MSCs possess comparable, in some instances, even better, therapeutic potential as that shown by human bone marrow-derived (hBMSC) or human umbilical cord-derived (hUC-MSC) MSCs. The placenta can be easily sourced from the OB/GYN department of any hospital, and if its derivatives such as hPMSC or their EVs are produced under GMP conditions, it could serve as a gold mine for translational/clinical research. Here, we have reviewed recent studies revealing the therapeutic potential of hPMSC and their extracellular vesicles (EVs) published over the past three years.

Targeting Interleukin-2-Inducible T-Cell Kinase (ITK) Differentiates GVL and GVHD in Allo-HSCT

Allogeneic hematopoietic stem cell transplantation is a potentially curative procedure for many malignant diseases. Donor T cells prevent disease recurrence via graft-versus-leukemia (GVL) effect. Donor T cells also contribute to graft-versus-host disease (GVHD), a debilitating and potentially fatal complication. Novel treatment strategies are needed which allow preservation of GVL effects without causing GVHD. Using murine models, we show that targeting IL-2-inducible T cell kinase (ITK) in donor T cells reduces GVHD while preserving GVL effects. Both CD8⁺ and CD4⁺ donor T cells from Itk^-/- mice produce less inflammatory cytokines and show decrease migration to GVHD target organs such as the liver and small intestine, while maintaining GVL efficacy against primary B-cell acute lymphoblastic leukemia (B-ALL). Itk^-/- T cells exhibit reduced expression of IRF4 and decreased JAK/STAT signaling activity but upregulating expression of Eomesodermin (Eomes) and preserve cytotoxicity, necessary for GVL effect. Transcriptome analysis indicates that ITK signaling controls chemokine receptor expression during alloactivation, which in turn affects the ability of donor T cells to migrate to GVHD target organs. Our data suggest that inhibiting ITK could be a therapeutic strategy to reduce GVHD while preserving the beneficial GVL effects following allo-HSCT treatment.

hPMSCs protects against D-galactose-induced oxidative damage of CD4+ T cells through activating Akt-mediated Nrf2 antioxidant signaling

Background

Mesenchymal stem cells (MSCs) were considered a regenerative therapeutic approach in both acute and chronic diseases. However, whether MSCs regulate the antioxidant metabolism of CD4⁺ T cells and weaken immunosenescence remains unclear. Here, we reported the protective effects of hPMSCs in aging-related CD4⁺ T cell senescence and identified the underlying mechanisms using a d-gal-induced mouse aging model.

Methods

In vivo study, 40 male C57BL/6 mice (8 weeks) were randomly divided into four groups: control group, d-gal group, hPMSC group, and PBS group. In in vitro experiment, human naive CD4⁺ T (CD4CD45RA) cells were prepared using a naive CD4⁺ T cell isolation kit II and pretreated with the Akt inhibitor LY294002 and Nrf2 inhibitor ML385. Then, isolated naive CD4⁺ T cell were co-cultured with hPMSCs for 72 h in the absence or presence of anti-CD3/CD28 Dynabeads and IL-2 as a mitogenic stimulus. Intracellular ROS changes were detected by flow cytometry. The activities of the antioxidant enzymes superoxide dismutase, glutathione peroxidase, and catalase were measured by colorimetric analysis. The senescent T cells were detected SA-β-gal stain. The expression of aging-related proteins was detected by Western blotting, RT-PCR, and confocal microscopy.

Results

We found that hPMSC treatment markedly decreased the ROS level, SA-β-gal-positive cells number, senescence-associated secretory phenotype (IL-6 and OPN) expression, and aging-related protein (P16 and P21) expression in senescent CD4⁺ T cells. Furthermore, hPMSC treatment effectively upregulated Nrf2 nuclear translocation and the expression of downstream target genes (HO-1, CAT, GCLC, and NQO1) in senescent CD4⁺ T cells. Moreover, in vitro studies revealed that hPMSCs attenuated CD4⁺ T cell senescence by upregulating the Akt/GSK-3β/Fyn pathway to activate Nrf2 functions. Conversely, the antioxidant effects of hPMSCs were blocked by the Akt inhibitor LY294002 and Nrf2 inhibitor ML385 in senescent CD4⁺ T cells.

Conclusions

Our results indicate that hPMSCs attenuate d-gal-induced CD4⁺ T cell senescence by activating Nrf2-mediated antioxidant defenses and that upregulation of Nrf2 by hPMSCs is regulated via the Akt/GSK-3β/Fyn pathway.

IL-27 Rα+ cells promoted allorejection via enhancing STAT1/3/5 phosphorylation

Recently, emerging evidence strongly suggested that the activation of interleukin-27 Receptor α (IL-27Rα) could modulate different inflammatory diseases. However, whether IL-27Rα affects allotransplantation rejection is not fully understood. Here, we investigated the role of IL-27Rα on allorejection both in vivo and in vitro. The skin allotransplantation mice models were established, and the dynamic IL-27Rα/IL-27 expression was detected, and IL-27Rα⁺ spleen cells adoptive transfer was performed. STAT1/3/5 phosphorylation, proliferation and apoptosis were investigated in mixed lymphocyte reaction (MLR) with recombinant IL-27 (rIL-27) stimulation. Finally, IFN-γ/ IL-10 in graft/serum from model mice was detected. Results showed higher IL-27Rα/IL-27 expression in allografted group compared that syngrafted group on day 10 (top point of allorejection). IL-27Rα⁺ spleen cells accelerated allograft rejection in vivo. rIL-27 significantly promoted proliferation, inhibited apoptosis and increased STAT1/3/5 phosphorylation of alloreactive splenocytes, and these effects of rIL-27 could be almost totally blocked by JAK/ STAT inhibitor and anti-IL-27 p28 Ab. Finally, higher IL-27Rα⁺ IFN-γ⁺ cells and lower IL-27Rα⁺ IL-10⁺ cells within allografts, and high IFN-γ/low IL-10 in serum of allorejecting mice were detected. In conclusion, these data suggested that IL-27Rα⁺ cells apparently promoted allograft rejection through enhancing alloreactive proliferation, inhibiting apoptosis and up-regulating IFN-γ via enhancing STAT pathway. Blocking IL-27 pathway may favour to prevent allorejection, and IL-27Rα may be as a high selective molecule for targeting diagnosis and therapy for allotransplantation rejection.

IL-1β enhances human placenta-derived mesenchymal stromal cells ability to mediate Th1/Th2 and Th1/CD4+IL-10+ T cell balance and regulates its adhesion, proliferation and migration via PD-L1

Human placenta-derived mesenchymal stromal cells (hPMSCs) are promising candidates for the treatment of graft-versus-host disease (GVHD), which is associated with high IL-1β levels. In this study, the effects of IL-1β and hPMSCs on each other were investigated by analyzing the proportion of Th1, Th2 and CD4⁺IL-10⁺ T cells and PD-L1 expression, as well as the adhesion, migration, and proliferation of hPMSCs. The results showed that hPMSCs decreased IL-1β levels and downregulated Th1/Th2 and Th1/CD4⁺IL-10⁺ T cells ratios in the GVHD model. The in vitro results revealed that IL-1β strengthened the hPMSCs capacity to reduce the Th1/Th2 and Th1/CD4⁺IL-10⁺ T cell ratios, inhibited the adhesion and proliferation of hPMSCs and increased PD-L1 expression on hPMSCs via the JAK and NF-κB pathways. Overall, these findings suggested that hPMSCs alleviate GVHD by decreasing IL-1β level and maintaining the balance among different T cell subsets. IL-1β enhanced the ability of hPMSCs to balance different T cell subsets and inhibited hPMSCs adhesion and proliferation by regulating PD-L1 expression via the JAK and NF-κB pathways.

Human placenta derived mesenchymal stromal cells alleviate GVHD by promoting the generation of GSH and GST in PD-1+T cells

AIMS

To investigate whether placenta-derived mesenchymal stromal cells (hPMSCs) have immunoregulatory effects on PD-1⁺ T cell generation by controlling ROS production and thus alleviating GVHD.

MAIN METHODS

Flow cytometry was used to analyze the percentage of PD-1⁺ T cells, as well as the generation of ROS, GSH and GST in PD-1⁺ T cells. The expression of GST in the spleen and liver was analyzed by western blotting.

KEY FINDINGS

The percentage of PD-1⁺ T cells was increased, but the ratio of GSH/GSSG was decreased in GVHD patients and the GVHD^high mouse model compared with that in the normal control group. hPMSCs downregulated the level of malondialdehyde (MDA) and upregulated the ratio of GSH/GSSG and the expression of glutathione S transferase (GST) in the plasma, spleen and liver of GVHD mice compared with those of PBS-treated GVHD mice. Further studies showed that the ROS level, as well as the expression of PD-1, in both CD3⁺ and CD4⁺ T cells from the spleen and liver of hPMSC-treated GVHD mice were decreased compared with those observed in PBS-treated mice.

SIGNIFICANCE

hPMSCs downregulated ROS generation by increasing GSH and GST levels and further reduced the expression of PD-1 on T cells, thereby alleviating inflammation in GVHD mice.