Glutamine supplementation improves the activity and immunosuppressive action of induced regulatory T cells in vitro and in vivo.

BACKGROUND: Glutamine is crucial for the activation and efficacy of T cells, and may play a role in regulating the immune environment. This study aimed to investigate the potential role of glutamine in the activation and proliferation of induced regulatory T cells (iTregs). METHODS: CD4+CD45RA+T cells were sorted from peripheral blood mononuclear cells and cultured to analyze iTreg differentiation. Glutamine was then added to the culture system to evaluate the effects of glutamine on iTregs by determining oxidative phosphorylation (OXPHOS), apoptosis, and cytokine secretion. Additionally, a humanized murine graft-versus-host disease (GVHD) model was constructed to confirm the efficacy of glutamine-treated iTregs in vivo. RESULTS: After being cultured in vitro, glutamine significantly enhanced the levels of Foxp3, CTLA-4, CD39, CD69, IL-10, TGF-ß, and Ki67 (CTLA-4, IL-10, TGF-ß are immunosuppressive markers of iTregs) compared with that of the control iTregs (P < 0.05). Furthermore, the growth curve showed that the proliferative ability of glutamine-treated iTregs was better than that of the control iTregs (P < 0.01). Compared with the control iTregs, glutamine supplementation significantly increased oxygen consumption rates and ATP production (P < 0.05), significantly downregulated Annexin V and Caspase 3, and upregulated BCL2 (P < 0.05). However, GPNA significantly reversed the effects of glutamine (P < 0.05). Finally, a xeno-GVHD mouse model was successfully established to confirm that glutamine-treated iTregs increased the mice survival rate, delayed weight loss, and alleviated colon injury. CONCLUSION: Glutamine supplementation can improve the activity and immunosuppressive action of iTregs, and the possible mechanisms by which this occurs are related to cell proliferation, apoptosis, and OXPHOS.

DNA/RNA heteroduplex oligonucleotide technology for regulating lymphocytes in vivo.

Manipulating lymphocyte functions with gene silencing approaches is promising for treating autoimmunity, inflammation, and cancer. Although oligonucleotide therapy has been proven to be successful in treating several conditions, efficient in vivo delivery of oligonucleotide to lymphocyte populations remains a challenge. Here, we demonstrate that intravenous injection of a heteroduplex oligonucleotide (HDO), comprised of an antisense oligonucleotide (ASO) and its complementary RNA conjugated to α-tocopherol, silences lymphocyte endogenous gene expression with higher potency, efficacy, and longer retention time than ASOs. Importantly, reduction of Itga4 by HDO ameliorates symptoms in both adoptive transfer and active experimental autoimmune encephalomyelitis models. Our findings reveal the advantages of HDO with enhanced gene knockdown effect and different delivery mechanisms compared with ASO. Thus, regulation of lymphocyte functions by HDO is a potential therapeutic option for immune-mediated diseases.

Mitochondrial complex II in intestinal epithelial cells regulates T cell-mediated immunopathology.

Intestinal epithelial cell (IEC) damage by T cells contributes to graft-versus-host disease, inflammatory bowel disease and immune checkpoint blockade-mediated colitis. But little is known about the target cell-intrinsic features that affect disease severity. Here we identified disruption of oxidative phosphorylation and an increase in succinate levels in the IECs from several distinct in vivo models of T cell-mediated colitis. Metabolic flux studies, complemented by imaging and protein analyses, identified disruption of IEC-intrinsic succinate dehydrogenase A (SDHA), a component of mitochondrial complex II, in causing these metabolic alterations. The relevance of IEC-intrinsic SDHA in mediating disease severity was confirmed by complementary chemical and genetic experimental approaches and validated in human clinical samples. These data identify a critical role for the alteration of the IEC-specific mitochondrial complex II component SDHA in the regulation of the severity of T cell-mediated intestinal diseases.

A novel study on the immunomodulatory effect of umbilical cord derived mesenchymal stem cells pretreated with traditional Chinese medicine Asarinin.

Allogeneic hematopoietic stem cell transplantation (HSCT) remains the key for the treatment of malignant hematological diseases, and acute graft-versus-host disease (aGVHD) that might occur after allogenic transplantation can be life threatening and promote disease recurrence. GVHD damages the various parts of the body by upregulating T helper 1 cytokines (Th1) cytokines and stimulating CD4、CD8 + T cells. GVHD can exhibit significant immunoregulatory effects, but could be easily affected by the mesenchymal stem cells (MSC) environment, and hence the MSC immunosuppressive effects on GVHD remain unpredictable. Hence, to better understand the role of MSC in the prevention and treatment of GVHD, umbilical cord derived mesenchymal stem cells (UC-MSC) were pre-treated with Chinese medicine Asarinin and IFN-γ. In the mix lymphocyte reaction, we found that Asarinin pre-treated UC-MSC can exert significantly greater inhibition towards the proliferation of CD4 and CD8 + T cells, down-regulate Th1 type cytokines, up-regulate Th2 type cytokines, and reduce the inflammatory damage to liver, lung and intestine of aGVHD mice model. Moreover, Asarinin can cooperate with IFN-γto promote UC-MSC to secrete indoleamine 2,3-dioxygenase (IDO). Our findings establish that Asarinin pre-treated UC-MSC can significantly promote the immunosuppressive effects of MSC on aGVHD after hematopoietic stem cell transplantation.

The Yin and Yang of Type 1 Regulatory T Cells: From Discovery to Clinical Application.

Regulatory T cells are essential players of peripheral tolerance and suppression of inflammatory immune responses. Type 1 regulatory T (Tr1) cells are FoxP3- regulatory T cells induced in the periphery under tolerogenic conditions. Tr1 cells are identified as LAG3+CD49b+ mature CD4+ T cells that promote peripheral tolerance through secretion of IL-10 and TGF-ß in addition to exerting perforin- and granzyme B-mediated cytotoxicity against myeloid cells. After the initial challenges of isolation were overcome by surface marker identification, ex vivo expansion of antigen-specific Tr1 cells in the presence of tolerogenic dendritic cells (DCs) and IL-10 paved the way for their use in clinical trials. With one Tr1-enriched cell therapy product already in a Phase I clinical trial in the context of allogeneic hematopoietic stem cell transplantation (allo-HSCT), Tr1 cell therapy demonstrates promising results so far in terms of efficacy and safety. In the current review, we identify developments in phenotypic and molecular characterization of Tr1 cells and discuss the potential of engineered Tr1-like cells for clinical applications of Tr1 cell therapies. More than 3 decades after their initial discovery, Tr1 cell therapy is now being used to prevent graft versus host disease (GvHD) in allo-HSCT and will be an alternative to immunosuppression to promote graft tolerance in solid organ transplantation in the near future.

Pretransplant Short-Term Exposure of Donor Graft Cells to ITK Selective Inhibitor Ameliorates Acute Graft-versus-Host Disease by Inhibiting Effector T Cell Differentiation while Sparing Regulatory T Cells.

Graft-versus-host disease (GVHD) remains to be a significant cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). IL-2-inducible T cell kinase (ITK), a TEC cytoplasmic tyrosine kinase, has an essential role in T cell development and receptor signaling. The ITK/Bruton tyrosine kinase inhibitor ibrutinib has been shown to improve chronic GVHD symptoms; however, the effect of ITK selective inhibition on acute GVHD remains unclear. In this study, we evaluated the pharmacological effects of an ITK selective inhibitor (ITKsi) on acute GVHD using murine bone marrow transplantation models. First, we found that CD4+ T cell differentiation toward Th1, Th2, or Th17 was inhibited following ITKsi treatment in a dose-dependent manner while maintaining regulatory T cells in the presence of alloantigens both in vitro and in vivo. ITKsi preferentially inhibited inflammatory cytokine production and in vivo proliferation of alloreactive T cells. We then demonstrated that short-term exposure of donor graft cells to ITKsi significantly delayed the onset of GVHD-associated mortality without compromising the donor cell engraftment and the graft-versus-tumor effect, indicating the potential of ITK selective inhibition in the setting of clinical allogeneic HSCT. These findings suggest that ITK is a potential therapeutic target against GVHD, and the pharmacological ITK inhibitor may serve as a novel strategy for immune regulation after HSCT.

Tocilizumab as first-line therapy for steroid-refractory acute graft-versus-host-disease: analysis of a single-center experience.

Acute graft-versus-host-disease (aGVHD) is a complication after allogeneic stem cell transplant. After the failure of treatment with high dose corticosteroids, steroid-refractory aGVHD (SR aGVHD) is associated with high rates of mortality. Tocilizumab has evidence of activity in SR aGVHD. For patients ineligible for trials, the OSU James Comprehensive Cancer Center has been utilizing tocilizumab as first-line therapy for SR aGVHD. We retrospectively report on 15 patients who received tocilizumab. aGVHD grading and responses were based on consensus criteria. Median age at transplant was 49 years. Median time to tocilizumab administration was 9 days (range, 3-16). Six patients had complete responses (40%) with a resolution of aGVHD. From the last contact, median overall survival for responders was not yet reached vs. 31 days for non-responders (p = .0002). Patients with skin and/or GI aGVHD demonstrated the greatest benefit. Patients with liver aGVHD did not respond. Future studies are needed to evaluate tocilizumab prior to steroid failure.

The Gut Microbiota and Hematopoietic Stem Cell Transplantation: Challenges and Potentials.

The human gut microbiota gained tremendous importance in the last decade as next-generation technologies of sequencing and multiomics analyses linked the role of the microbial communities to host physiology and pathophysiology. A growing number of human pathologies and diseases are linked to the gut microbiota. One of the main mechanisms by which the microbiota influences the host is through its interactions with the host immune system. These interactions with both innate and adaptive host intestinal and extraintestinal immunity, although usually commensalistic even mutualistic with the host, in some cases lead to serious health effects. In the case of allogenic hematopoietic stem cell transplantation (allo-HSCT), the disruption of the intestinal microbiota diversity is associated with acute graft-versus-host disease (GvHD). Causing inflammation of the liver, skin, lungs, and the intestine, GvHD occurs in 40-50% of patients undergoing allo-HSCT and results in significant posttransplantation mortality. In this review, we highlight the impact of the gut microbiota on the host immunity in GvHD and the potential of microbiota in alleviation or even prevention of GvHD.

SYK inhibitor entospletinib prevents ocular and skin GVHD in mice.

Graft-versus-host disease (GVHD) is a major complication of hematopoietic stem cell transplantation (HCT). The tyrosine kinase SYK contributes to both acute and chronic GVHD development, making it an attractive target for GVHD prevention. Entospletinib (ENTO) is a second-generation highly selective SYK inhibitor with a high safety profile. Potential utility of ENTO as GVHD prophylaxis in patients was examined using a preclinical mouse model of eye and skin GVHD and ENTO-compounded chow. We found that early SYK inhibition improved blood immune cell reconstitution in GVHD mice and prolonged survival, with 60% of mice surviving to day +120 compared with 10% of mice treated with placebo. Compared with mice receiving placebo, mice receiving ENTO had dramatic improvements in clinical eye scores, alopecia scores, and skin scores. Infiltrating SYK+ cells expressing B220 or F4/80, resembling SYK+ cells found in lichenoid skin lesions of chronic GVHD patients, were abundant in the skin of placebo mice but were rare in ENTO-treated mice. Thus, ENTO given early after HCT safely prevented GVHD.

Notch signaling mediated by Delta-like ligands 1 and 4 controls the pathogenesis of chronic GVHD in mice.

Chronic graft-versus-host disease (cGVHD) is a major complication of allogeneic hematopoietic cell transplantation (allo-HCT) and remains an area of unmet clinical need with few treatment options available. Notch blockade prevents acute GVHD in multiple mouse models, but the impact of Notch signaling on cGVHD remains unknown. Using genetic and antibody-mediated strategies of Notch inhibition, we investigated the role of Notch signaling in complementary mouse cGVHD models that mimic several aspects of human cGVHD in search of candidate therapeutics. In the B10.D2→BALB/c model of sclerodermatous cGVHD, Delta-like ligand 4 (Dll4)-driven Notch signaling was essential for disease development. Antibody-mediated Dll4 inhibition conferred maximum benefits when pursued early in a preventative fashion, with anti-Dll1 enhancing early protection. Notch-deficient alloantigen-specific T cells showed no early defects in proliferation or helper polarization in vivo but subsequently exhibited markedly decreased cytokine secretion and enhanced accumulation of FoxP3+ regulatory T cells. In the B6→B10.BR major histocompatibility complex-mismatched model with multi-organ system cGVHD and prominent bronchiolitis obliterans (BO), but not skin manifestations, absence of Notch signaling in T cells provided long-lasting disease protection that was replicated by systemic targeting of Dll1, Dll4, or both Notch ligands, even during established disease. Notch inhibition decreased target organ damage and germinal center formation. Moreover, decreased BO-cGVHD was observed upon inactivation of Notch1 and/or Notch2 in T cells. Systemic targeting of Notch2 alone was safe and conferred therapeutic benefits. Altogether, Notch ligands and receptors regulate key pathogenic steps in cGVHD and emerge as novel druggable targets to prevent or treat different forms of cGVHD.

Update of humanized animal disease models in studying Graft-versus-host disease.

Graft-versus-host disease (GVHD) is a severe adverse effect that results from bone marrow or peripheral blood cells transplantation and has a high rate of mortality. About 50% of the patients are accompanied with acute Graft-versus-Host Disease (aGVHD) after bone marrow cell transplantation and need systematic treatment. It has an important clinical significance to evaluate the prevention and treatment effects of GVHD. The stable and reliable approaches of humanized animal models are crucial for advancing on the study the biology of GVHD. Relative models transplanting the human immune cells into the mouse body can trigger immunoreaction similar to the humans. As it is a disease triggered by human immune cells, any intervention research prior to clinical treatment has more clinical interrelations compared with the general animal models. In this review, we update the current understanding on humanized animal disease models on studying Graft-versus-host disease and expect to provide more theoretical basis to further study on Graft-versus-host disease.

Anncaliia algerae Microsporidial Myositis, New South Wales, Australia.

We describe the successful management of Anncaliia algerae microsporidial myositis in a man with graft versus host disease after hemopoietic stem cell transplantation. We also summarize clinical presentation and management approaches and discuss the importance of research into the acquisition of this infection and strategies for prevention.

Autologous transplantation versus allogeneic transplantation in patients with follicular lymphoma experiencing early treatment failure.

BACKGROUND: Early treatment failure (ETF) in follicular lymphoma (FL), defined as relapse or progression within 2 years of frontline chemoimmunotherapy, is a newly recognized marker of poor survival and identifies a high-risk group of patients with an expected 5-year overall survival (OS) rate of approximately 50%. Transplantation is an established option for relapsed FL, but its efficacy in this specific ETF FL population has not been previously evaluated. METHODS: This study compared autologous hematopoietic stem cell transplantation (auto-HCT) with either matched sibling donor (MSD) or matched unrelated donor (MUD) allogeneic hematopoietic cell transplantation (allo-HCT) as the first transplantation approach for patients with ETF FL (age ≥ 18 years) undergoing auto-HCT or allo-HCT between 2002 and 2014. The primary endpoint was OS. The secondary endpoints were progression-free survival, relapse, and nonrelapse mortality (NRM). RESULTS: Four hundred forty FL patients had ETF (auto-HCT, 240; MSD hematopoietic stem cell transplantation [HCT], 105; and MUD HCT, 95). With a median follow-up of 69 to 73 months, the adjusted probability of 5-year OS was significantly higher after auto-HCT (70%) or MSD HCT (73%) versus MUD HCT (49%; P = .0008). The 5-year adjusted probability of NRM was significantly lower for auto-HCT (5%) versus MSD (17%) or MUD HCT (33%; P < .0001). The 5-year adjusted probability of disease relapse was lower with MSD (31%) or MUD HCT (23%) versus auto-HCT (58%; P < .0001). CONCLUSIONS: Patients with high-risk FL, as defined by ETF, undergoing auto-HCT for FL have low NRM and a promising 5-year OS rate (70%). MSD HCT has lower relapse rates than auto-HCT but similar OS. Cancer 2018;124:2541-51. © 2018 American Cancer Society.

BET Bromodomain Inhibitors Which Permit Treg Function Enable a Combinatorial Strategy to Suppress GVHD in Pre-clinical Allogeneic HSCT.

A recent approach for limiting production of pro-inflammatory cytokines has been to target bromodomain and extra-terminal (BET) proteins. These epigenetic readers of histone acetylation regulate transcription of genes involved in inflammation, cardiovascular disease, and cancer. Development of BET inhibitors (BETi) has generated enormous interest for their therapeutic potential. Because inflammatory signals and donor T cells promote graft-versus-host disease (GVHD), regulating both pathways could be effective to abrogate this disorder. The objective of the present study was to identify a BETi which did not interfere in vivo with CD4+FoxP3+ regulatory T cell (Treg) expansion and function to utilize together with Tregs following allogeneic hematopoietic stem cell transplantation (aHSCT) to ameliorate GVHD. We have reported that Tregs can be markedly expanded and selectively activated with increased functional capacity by targeting TNFRSF25 and CD25 with TL1A-Ig and low dose IL-2, respectively. Here, mice were treated over 7 days (TL1A-Ig + IL-2) together with BETi. We found that the BETi EP11313 did not decrease frequency/numbers or phenotype of expanded Tregs as well as effector molecules, such as IL-10 and TGF-ß. However, BETi JQ1 interfered with Treg expansion and altered subset distribution and phenotype. Notably, in Treg expanded mice, EP11313 diminished tnfa and ifng but not il-2 RNA levels. Remarkably, Treg pSTAT5 expression was not affected by EP11313 supporting the notion that Treg IL-2 signaling remained intact. MHC-mismatched aHSCT (B6 → BALB/c) was performed using in vivo expanded donor Tregs with or without EP11313 short-term treatment in the recipient. Early post-transplant, improvement in the splenic and LN CD4/CD8 ratio along with fewer effector cells and high Treg levels in aHSCT recipients treated with expanded Tregs + EP11313 was detected. Interestingly, this group exhibited a significant diminution of GVHD clinical score with less skin and ocular involvement. Finally, using low numbers of highly purified expanded Tregs, improved clinical GVHD scores were observed in EP11313 treated recipients. In total, we conclude that use of this novel combinatorial strategy can suppress pre-clinical GVHD and posit, in vivo EP11313 treatment might be useful combined with Treg expansion therapy for treatment of diseases involving inflammatory responses.

Migratory properties of ex vivo expanded regulatory T cells: Influence of all-trans retinoic acid and rapamycin.

Adoptively transferred regulatory T-cells represent a promising therapeutic approach for tolerance induction in autoimmunity and transplantation medicine. However, a major hurdle for clinical application is the manufacturing of sufficient Treg cell numbers with respect to the low frequency of naturally occurring Tregs in the peripheral blood. Therefore, ex vivo large-scale expansion is mandatory for most of the clinical conditions. Besides the Treg cell number other parameters of the cell product are of high relevance for safe and efficient clinical Treg cell application like Treg cell purity, suppressive capacity and genetic stability of the Treg cell phenotype. Moreover, migratory properties of ex vivo expanded Tregs should be defined very clearly in order to predict their migration to secondary lymphoid organs as sites of antigen-specific activation, in vivo proliferation and subsequent trafficking to affected target organs. Therefore, we studied different cell culture conditions for Treg large-cell expansion using all-trans retinoic acid (ATRA) and/or rapamycin (Rapa) with focus on their migratory properties. The tested culture conditions revealed comparable chemokine receptor expression profiles (CXCR3, CCR4, CCR6, CCR7) and functional migration capabilities (IP10 and CCL19) with respect to Th1 and Th2 inflammatory conditions. However, the most striking difference was detected for the expansion capacity, suppressive potency and genetic stability likely predisposing large-scale expansion with ATRA and/or Rapa for therapeutic intervention in acute GvHD and without supplementation for chronic GvHD.

Immunomodulatory Effect of Vitamin D after Allogeneic Stem Cell Transplantation: Results of a Prospective Multicenter Clinical Trial.

PURPOSE: We describe the results of a prospective multicenter phase I/II trial evaluating the impact of the use of vitamin D (VitD) from day -5 to +100 on the outcome of patients undergoing allogeneic transplantation (EudraCT: 2010-023279-25; ClinicalTrials.gov: NCT02600988). EXPERIMENTAL DESIGN: A total of 150 patients were included in three consecutive cohorts of 50 patients each group: control group (CG, not receive VitD); low-dose group (LdD, received 1,000 IU VitD daily); and high-dose group (HdD, 5,000 IU VitD daily). We measured levels of VitD, cytokines, and immune subpopulations after transplantation. RESULTS: No significant differences were observed in terms of cumulative incidence of overall and grades 2-4 acute GVHD in terms of relapse, nonrelapse mortality, and overall survival. However, a significantly lower cumulative incidence of both overall and moderate plus severe chronic GVHD (cGVHD) at 1 year was observed in LdD (37.5% and 19.5%, respectively) and HdD (42.4% and 27%, respectively) as compared with CG (67.5% and 44.7%, respectively; P < 0.05). In multivariable analysis, treatment with VitD significantly decreased the risk of both overall (for LdD: HR = 0.31, P = 0.002; for HdD: HR = 0.36, P = 0.006) and moderate plus severe cGVHD (for LdD: HR = 0.22, P = 0.001; for HdD: HR = 0.33, P = 0.01). VitD modified the immune response, decreasing the number of B cells and naïve CD8 T cells, with a lower expression of CD40L. CONCLUSIONS: This is the first prospective trial that analyzes the effect of VitD postransplant. We observed a significantly lower incidence of cGVHD among patients receiving VitD. Interestingly, VitD modified the immune response after allo-SCT. Clin Cancer Res; 22(23); 5673-81. ©2016 AACR.

Targeting T Cell Bioenergetics by Modulating P-Glycoprotein Selectively Depletes Alloreactive T Cells To Prevent Graft-versus-Host Disease.

T lymphocytes play a central role in many human immunologic disorders, including autoimmune and alloimmune diseases. In hematopoietic stem cell transplantation, acute graft-versus-host-disease (GVHD) is caused by an attack on the recipient's tissues from donor allogeneic T cells. Selectively depleting GVHD-causing cells prior to transplant may prevent GVHD. In this study, we evaluated 24 chalcogenorhodamine photosensitizers for their ability to selectively deplete reactive T lymphocytes and identified the photosensitizer 2-Se-Cl, which accumulates in stimulated T cells in proportion to oxidative phosphorylation. The photosensitizer is also a potent stimulator of P-glycoprotein (P-gp). Enhanced P-gp activity promotes the efficient removal of photosensitizer not sequestered in mitochondria and protects resting lymphocytes that are essential for antipathogen and antitumor responses. To evaluate the selective depletion of alloimmune responses, donor C57BL/6 splenocytes were cocultured for 5 d with irradiated BALB/c splenocytes and then photodepleted (PD). PD-treated splenocytes were infused into lethally irradiated BALB/c (same-party) or C3H/HeJ (third-party) mice. Same-party mice that received PD-treated splenocytes at the time of transplant lived 100 d without evidence of GVHD. In contrast, all mice that received untreated primed splenocytes and third-party mice that received PD-treated splenocytes died of lethal GVHD. To evaluate the preservation of antiviral immune responses, acute lymphocytic choriomeningitis virus infection was used. After photodepletion, expansion of Ag-specific naive CD8(+) T cells and viral clearance remained fully intact. The high selectivity of this novel photosensitizer may have broad applications and provide alternative treatment options for patients with T lymphocyte-mediated diseases.

Narrow-Band Ultraviolet B Phototherapy Ameliorates Acute Graft-Versus-Host Disease of the Intestine by Expansion of Regulatory T Cells.

Narrowband ultraviolet B (NB-UVB) has been widely used in dermatological phototherapy. As for the application of NB-UVB phototherapy to graft-versus-host disease (GVHD), we previously reported that it was highly efficacious for cutaneous lesions of acute GVHD (aGVHD) and that expansion of regulatory T (Treg) cells induced by NB-UVB might be one of the mechanisms. In order to examine whether NB-UVB irradiation through expansion of Treg cells is effective for the treatment of not only cutaneous aGVHD but also aGVHD of inner organs such as the intestine or liver, we conducted experiments in which a murine lethal aGVHD model, characterized by severe involvement of the intestine, was irradiated with NB-UVB. We found that NB-UVB irradiation improved the clinical score and survival rate. The pathological score of aGVHD was improved in all affected organs: intestine, liver, and skin. In the serum of mice irradiated with NB-UVB, the levels of Treg cells-associated cytokines such as transforming growth factor beta (TGFß) and interleukin-10 (IL-10) were elevated. The numbers of infiltrating Treg cells in inflamed tissue of the intestine and those in spleen were increased in mice treated with NB-UVB. This is the first report demonstrating that NB-UVB phototherapy has the ability to ameliorate intestinal aGVHD through the expansion of Treg cells.

Comparative Analysis of Protocols to Induce Human CD4+Foxp3+ Regulatory T Cells by Combinations of IL-2, TGF-beta, Retinoic Acid, Rapamycin and Butyrate.

Regulatory T cells (Tregs) suppress other immune cells and are critical mediators of peripheral tolerance. Therapeutic manipulation of Tregs is subject to numerous clinical investigations including trials for adoptive Treg transfer. Since the number of naturally occurring Tregs (nTregs) is minute, it is highly desirable to develop a complementary approach of inducing Tregs (iTregs) from naïve T cells. Mouse studies exemplify the importance of peripherally induced Tregs as well as the applicability of iTreg transfer in different disease models. Yet, procedures to generate iTregs are currently controversial, particularly for human cells. Here we therefore comprehensively compare different established and define novel protocols of human iTreg generation using TGF-ß in combination with other compounds. We found that human iTregs expressed several Treg signature molecules, such as Foxp3, CTLA-4 and EOS, while exhibiting low expression of the cytokines Interferon-γ, IL-10 and IL-17. Importantly, we identified a novel combination of TGF-ß, retinoic acid and rapamycin as a robust protocol to induce human iTregs with superior suppressive activity in vitro compared to currently established induction protocols. However, iTregs generated by these protocols did not stably retain Foxp3 expression and did not suppress in vivo in a humanized graft-versus-host-disease mouse model, highlighting the need for further research to attain stable, suppressive iTregs. These results advance our understanding of the conditions enabling human iTreg generation and may have important implications for the development of adoptive transfer strategies targeting autoimmune and inflammatory diseases.

Coenzyme Q10 Exerts Anti-Inflammatory Activity and Induces Treg in Graft Versus Host Disease.

The objective of this study was to determine whether coenzyme Q10 (CoQ10) can reduce the severity of graft versus host disease (GVHD) by inducing regulatory T cells (Tregs). CoQ10 or vehicle was orally administrated once a day for 22 days to mice with GVHD. We measured the alloresponse of the T cells and the GVHD clinical scores. Real-time polymerase chain reaction was used to examine messenger RNA (mRNA) level. Flow cytometry and enzyme-linked immunosorbent assay were used to evaluate protein expression. CoQ10 reduced the T-cell alloresponse and the expression of interferon (IFN)-γ and interleukin (IL)-17. The severity of GVHD and gene expressions of IL-6 and tumor necrosis factor (TNF)-α decreased with CoQ10 treatment. Furthermore, CoQ10 promoted weight gain and survival in GVHD mice. Flow cytometry revealed that CoQ10 dose dependently induced Treg differentiation, but FK506, an immunosuppressive drug, decreased Treg differentiation dose dependently. In conclusion, CoQ10 downregulates the alloreactivity of T cells and reduces GVHD severity, enhancing the differentiation of Tregs.