Functional study of immature dendritic cells co-transfected with IL-10 and TGF-beta 1 genes in vitro

miR-199a-3p may be an early warning marker for acute rejection after liver transplantation in rats

BACKGROUND

Prevention of acute rejection is the key of the success of liver transplantation. However, there are no specific indicators available for prediction of acute rejection after liver transplantation. MicroRNAs (miRNAs) are highly conserved and small noncoding RNA molecules that can be detected in peripheral blood. Here, we evaluated the potential of circulating miRNAs to serve as noninvasive biomarkers for acute rejection after liver transplantation in rats.

METHODS

The liver grafts retrieved from Lewis rats were orthotopically transplanted into BN rats or Lewis rats in the acute rejection and immune tolerance group respectively, and the BN rats in the immune intervention group was intraperitoneally injected with transforming growth factor-β1 overexpressed immature dendritic cells to suppress acute rejection before orthotopically transplanted with livers from Lewis rats. MiRNAs profiling studies were used to determine the regulation of circulating miRNAs in plasma samples of rats. Candidate miRNA was verified by quantitative reverse transcriptase polymerase chain reaction. Furthermore, the relationship between candidate miRNA and acute rejection was also evaluated.

RESULTS

Microarray analysis revealed that miR-199a-3p was the mostly differentially regulated miRNAs in plasma samples among the three groups. The plasmid PCDH-CMV-EGFP-hTGF-β1 was identified by PCR and DNA sequencing, and successfully expressed in imDCs. There were differences in the expression of miR-199a-3p in the liver tissues of the AR group on the 3rd, 7th and 10th day after liver transplantation (all p < 0.01). With time, the RAI score increased gradually, and the difference of miR-199a-3p expression gradually increased (rs = 0.92, p < 0.001), suggesting that it may be related to acute rejection. The expression of miR-199a-3p in the serum of the AR and TGF-β1-imDCs groups gradually increased, reaching a peak at day 7 and then decreasing. There was positive relationship between the expression of miR-199a-3p and RAIs within 7 days post operation. (rs = 0.942, p < 0.05).

CONCLUSION

miR-199a-3p might be an early warning marker for acute rejection after liver transplantation in rats.

Regulatory Dendritic Cells, T Cell Tolerance, and Dendritic Cell Therapy for Immunologic Disease

Dendritic cells (DC) are antigen-presenting cells that can communicate with T cells both directly and indirectly, regulating our adaptive immune responses against environmental and self-antigens. Under some microenvironmental conditions DC develop into anti-inflammatory cells which can induce immunologic tolerance. A substantial body of literature has confirmed that in such settings regulatory DC (DCreg) induce T cell tolerance by suppression of effector T cells as well as by induction of regulatory T cells (Treg). Many in vitro studies have been undertaken with human DCreg which, as a surrogate marker of antigen-specific tolerogenic potential, only poorly activate allogeneic T cell responses. Fewer studies have addressed the abilities of, or mechanisms by which these human DCreg suppress autologous effector T cell responses and induce infectious tolerance-promoting Treg responses. Moreover, the agents and properties that render DC as tolerogenic are many and varied, as are the cells’ relative regulatory activities and mechanisms of action. Herein we review the most current human and, where gaps exist, murine DCreg literature that addresses the cellular and molecular biology of these cells. We also address the clinical relevance of human DCreg, highlighting the outcomes of pre-clinical mouse and non-human primate studies and early phase clinical trials that have been undertaken, as well as the impact of innate immune receptors and symbiotic microbial signaling on the immunobiology of DCreg.

Effects of IL-10- and FasL-overexpressing dendritic cells on liver transplantation tolerance in a heterotopic liver transplantation rat model

Acute rejection is the major determinant for the long-term survival of donor liver after liver transplantation (LT). The aim of this study was to examine the therapeutic potential of interleukin (IL)-10-FasL-overexpressing immature dendritic cells (imDCs) to induce local immunosuppression in liver grafts. imDCs derived from donors were transduced by lentiviral vectors expressing human IL-10 and/or Fas ligand (FasL) gene(s), and the expression of surface molecules and the ability to induce T-cell proliferation were measured. imDCs were intraperitoneally injected into recipient rats as a model of LT to examine the rejection grade [Banff rejection activity index (RAI)], liver functions [Alanine aminotransferase, Aspartate aminotransferase (AST) and total bilirubin (TBIL)] and post-transplant survival. IL-10 and FasL co-transduction of imDCs induced a greater reduction in CD80, CD86 and major histocompatibility complex class II (MHC II) expression, as well as T-cell proliferation, but increased levels of IL-10 and FasL in culture supernatants compared with mono-transduced or untransduced imDCs (P < 0.05). The infusion of co-transduced imDCs in LT recipients reduced RAI scores, decreased plasma AST and TBIL, and prolonged survival compared with mono-transduced or untransduced imDC-treated liver allografts. These findings demonstrated that the transfusion of IL-10-FasL/imDCs enhanced immune tolerance and prolonged the survival of liver allografts after LT. The immunomodulatory activity of IL-10- and FasL-modified imDCs might be a new therapeutic approach to prevent organ rejection in clinical transplantation.

Expression of a soluble IL-10 receptor enhances the therapeutic effects of a papillomavirus-associated antitumor vaccine in a murine model

The presence of IL-10, produced either by tumor cells or immunosuppressive cells, is frequently associated with a poor prognosis for cancer progression. It may also negatively impact anticancer treatments, such as immunotherapies, that otherwise would promote the activation of cytotoxic T cells capable of detecting and destroying malignant cells. In the present study, we evaluated a new adjuvant approach for anticancer immunotherapy using a plasmid vector encoding a soluble form of the IL-10 receptor (pIL-10R). pIL-10R was coadministered to mice with a DNA vaccine encoding the type 16 human papillomavirus (HPV-16) E7 oncoprotein genetically fused with glycoprotein D of herpes simplex virus (HSV) (pgDE7h). Immunization regimens based on the coadministration of pIL-10R and pgDE7h enhanced the antitumor immunity elicited in mice injected with TC-1 cells, which express HPV-16 oncoproteins. The administration of the DNA vaccines by in vivo electroporation further enhanced the anticancer effects of the vaccines, leading to the activation of tumor-infiltrating polyfunctional E7-specific cytotoxic CD8+ T cells and control of the expansion of immunosuppressive cells. In addition, the combination of immunotherapy and pIL-10R allowed the control of tumors in more advanced growth stages that otherwise would not be treatable by the pgDE7h vaccine. In conclusion, the proposed treatment involving the expression of IL-10R enhanced the antitumor protective immunity induced by pgDE7h administration and may contribute to the development of more efficient clinical interventions against HPV-induced tumors.

Synergistic effects of recombinant Lentiviral-mediated BMP2 and TGF-beta3 on the osteogenic differentiation of rat bone marrow mesenchymal stem cells in vitro

BACKGROUND

Bone marrow mesenchymal stem cells (BMSCs) are considered good candidates for seed cells in bone engineering. The study aim to investigate the synergistic effects of human bone morphogenetic protein 2 (hBMP2) and transforming growth factor beta3 (hTGF-beta3) modified BMSCs on inducing osteogenic differentiation in vitro.

METHODS

Lentivirus (LV) carrying hBMP2 and/or hTGF-beta3 genes were constructed and used to transduce rat BMSCs. The expression of osteogenic molecules was detected by qRT-PCR and western blotting.

RESULTS

Targeted genes were PCR-amplified and confirmed by DNA sequencing and BLAST analysis. BMSCs infected by vectors effectively resulted in the overexpressions of hBMP2 and hTGF-beta3 and higher levels of hBMP2 and hTGF-beta3 in the culture supernatant. The co-transduction of hBMP2 and hTGF-beta3 induced BMSCs osteogenic differentiation more effectively than the transduction of hBMP2 or hTGF-beta3 individually. The expression levels of osteopontin (OPN), osteocalcin (OCN), and osteoprotegerin (OPG) in LV-hBMP2 + LV-hTGF-beta3 group (BMSCs transfected by vectors respectively carrying hBMP-2 gene and hTGF-beta3 gene) and LV-hBMP2-hTGF-beta3 group (BMSCs transfected by vector carrying hBMP2 and hTGF-beta3 fusion gene) were significantly higher than in LV-BMP2 (BMSCs transfected by vector carrying hBMP2 gene) and LV-TGF-beta3 (BMSCs transfected by vector carrying hTGF-beta3 gene) groups (P < 0.05). The hBMP2 and/or hTGF-beta3 overexpression upregulated alkaline phosphatase (ALP) activity.

CONCLUSION

The present study showed that hBMP2 and/or hTGF-beta3 genes can be successfully overexpressed in BMSCs. Our study proved that the two cytokines (hBMP2 and hTGF-beta3) could induce bone differentiation synergistically, which foresees the use of the combination of these two cytokines as a therapeutic strategy in the future.

Prolonged survival effects induced by immature dendritic cells and regulatory T cells in a rat liver transplantation model

BACKGROUND

Dendritic cells (DCs) and regulatory T (Treg) cells are crucial for inducing immune tolerance. However, the suppressive function of infused Treg cells and immature DCs (imDCs) following solid organ transplantation remains unclear.

METHODS

ImDCs derived from DA-donor rats and Treg cells isolated from spleens of Lewis rats were prepared. A heterotopic liver transplantation model was established to examine the immune tolerance effects of infusion of Treg-imDCs, imDCs and Treg cells individually. Th1/Th2 cytokines and TRAL were detected by ELISA. The overall rejection grade was assessed and the rejection activity index (RAI) was calculated. TUNEL-positive lymphocytes were detected in the portal area in liver sections.

RESULTS

The infusion of Treg-imDCs was more effective than imDCs or Treg cells individually. Moreover, the expression of IL-10 and TGF-β1 was significantly up-regulated, and IL-12 expression was significantly down-regulated, especially in the Treg-imDCs group. The percentage of TUNEL-positive cells was significantly higher in the Treg cells and imDCs groups. The RAI values in Treg-imDCs group on days 3 and 7 were lower than control, imDCs and Treg cells groups individually (p<0.05). Both TBIL and ALT levels in the Treg-imDCs and imDCs groups were significantly lower than those of the control and Treg cells groups, and serum TRAL levels increased significantly 10days after transplantation in the imDC and Treg-imDC groups compared with the control and Treg cells groups (P<0.001).

CONCLUSION

These data demonstrated that infusion of Treg cells and/or imDCs induces alloantigen tolerance and prolongs liver allograft survival. The infusion of Treg-imDCs was more effective than imDCs or Treg cells individually. ImDCs synergize with Treg cells in inducing and maintaining the feedback loop between imDCs and Treg cells in vivo.

Regulation of Natural Killer Cell Function by STAT3

Natural killer (NK) cells, key members of a distinct hematopoietic lineage, innate lymphoid cells, are not only critical effectors that mediate cytotoxicity toward tumor and virally infected cells but also regulate inflammation, antigen presentation, and the adaptive immune response. It has been shown that NK cells can regulate the development and activation of many other components of the immune response, such as dendritic cells, which in turn, modulate the function of NK cells in multiple synergistic feed back loops driven by cell–cell contact, and the secretion of cytokines and chemokines that control effector function and migration of cells to sites of immune activation. The signal transducer and activator of transcription (STAT)-3 is involved in driving almost all of the pathways that control NK cytolytic activity as well as the reciprocal regulatory interactions between NK cells and other components of the immune system. In the context of tumor immunology, NK cells are a first line of defense that eliminates pre-cancerous and transformed cells early in the process of carcinogenesis, through a mechanism of “immune surveillance.” Even after tumors become established, NK cells are critical components of anticancer immunity: dysfunctional NK cells are often found in the peripheral blood of cancer patients, and the lack of NK cells in the tumor microenvironment often correlates to poor prognosis. The pathways and soluble factors activated in tumor-associated NK cells, cancer cells, and regulatory myeloid cells, which determine the outcome of cancer immunity, are all critically regulated by STAT3. Using the tumor microenvironment as a paradigm, we present here an overview of the research that has revealed fundamental mechanisms through which STAT3 regulates all aspects of NK cell biology, including NK development, activation, target cell killing, and fine tuning of the innate and adaptive immune responses.

The siRNA cocktail targeting interleukin 10 receptor and transforming growth factor-β receptor on dendritic cells potentiates tumour antigen-specific CD8(+) T cell immunity

Dendritic cells (DCs) are promising therapeutic agents in the field of cancer immunotherapy due to their intrinsic immune-priming capacity. The potency of DCs, however, is readily attenuated immediately after their administration in patients as tumours and various immune cells, including DCs, produce various immunosuppressive factors such as interleukin (IL)-10 and transforming growth factor (TGF)-β that hamper the function of DCs. In this study, we used small interfering RNA (siRNA) to silence the expression of endogenous molecules in DCs, which can sense immunosuppressive factors. Among the siRNAs targeting various immunosuppressive molecules, we observed that DCs transfected with siRNA targeting IL-10 receptor alpha (siIL-10RA) initiated the strongest antigen-specific CD8(+) T cell immune responses. The potency of siIL-10RA was enhanced further by combining it with siRNA targeting TGF-β receptor (siTGF-βR), which was the next best option during the screening of this study, or the previously selected immunoadjuvant siRNA targeting phosphatase and tensin homologue deleted on chromosome 10 (PTEN) or Bcl-2-like protein 11 (BIM). In the midst of sorting out the siRNA cocktails, the cocktail of siIL-10RA and siTGF-βR generated the strongest antigen-specific CD8(+) T cell immunity. Concordantly, the knock-down of both IL-10RA and TGF-βR in DCs induced the strongest anti-tumour effects in the TC-1 P0 tumour model, a cervical cancer model expressing the human papillomavirus (HPV)-16 E7 antigen, and even in the immune-resistant TC-1 (P3) tumour model that secretes more IL-10 and TGF-β than the parental tumour cells (TC-1 P0). These results provide the groundwork for future clinical development of the siRNA cocktail-mediated strategy by co-targeting immunosuppressive molecules to enhance the potency of DC-based vaccines.

Cotransfection with IL-10 and TGF-β1 into immature dendritic cells enhances immune tolerance in a rat liver transplantation model

Dendritic cells transfected with interleukin (IL)-10 and transforming growth factor-β1 (TGF-β1) enhance T cell immunity and tolerance. However, no quantitative studies have investigated the suppressive functions of immature dendritic cells (imDC) cotransfected with IL-10 and TGF-β1. The effects of imDC cotransfected with IL-10 and TGF-β1 (IL-10-TGF-β1-imDC) on immune tolerance induction in a rat transplantation model were investigated. In addition, effects of IL-10-TGF-β1-imDC relative to IL-10-transfected imDC (IL-10-imDC) and TGF-β1-transfected imDC (TGF-β1-imDC) were compared. The infusion of IL-10-TGF-β1-imDC into recipients prolonged liver graft survival, which was sustained for >90 days. IL-12 serum levels decreased, whereas alanine transaminase and total bilirubin slightly increased in rats infused with IL-10-TGF-β1-imDC compared with the IL-10-imDC and TGF-β1-imDC groups. Furthermore, a higher percentage of terminal transferase-mediated UTP nick end-labeling-positive cells was observed, and histological analysis of the allografts indicated a rejection activity index of mild acute rejection. Our results suggest infusion of IL-10 and TGF-β1 cotransfected imDC induces alloantigen-specific T cell hyporesponsiveness, inhibits antigen-specific immunological responses to liver allografts, prolongs liver allograft survival, and enhances the immune tolerance. This approach may provide a promising alternative for enhancing donor-specific tolerance during liver transplantation.

Regulatory dendritic cells for immunotherapy in immunologic diseases

We recognize well the abilities of dendritic cells to activate effector T cell (Teff cell) responses to an array of antigens and think of these cells in this context as pre-eminent antigen-presenting cells, but dendritic cells are also critical to the induction of immunologic tolerance. Herein, we review our knowledge on the different kinds of tolerogenic or regulatory dendritic cells that are present or can be induced in experimental settings and humans, how they operate, and the diseases in which they are effective, from allergic to autoimmune diseases and transplant tolerance. The primary conclusions that arise from these cumulative studies clearly indicate that the agent(s) used to induce the tolerogenic phenotype and the status of the dendritic cell at the time of induction influence not only the phenotype of the dendritic cell, but also that of the regulatory T cell responses that they in turn mobilize. For example, while many, if not most, types of induced regulatory dendritic cells lead CD4⁺ naïve or Teff cells to adopt a CD25⁺Foxp3⁺ Treg phenotype, exposure of Langerhans cells or dermal dendritic cells to vitamin D leads in one case to the downstream induction of CD25⁺Foxp3⁺ regulatory T cell responses, while in the other to Foxp3⁻ type 1 regulatory T cells (Tr1) responses. Similarly, exposure of human immature versus semi-mature dendritic cells to IL-10 leads to distinct regulatory T cell outcomes. Thus, it should be possible to shape our dendritic cell immunotherapy approaches for selective induction of different types of T cell tolerance or to simultaneously induce multiple types of regulatory T cell responses. This may prove to be an important option as we target diseases in different anatomic compartments or with divergent pathologies in the clinic. Finally, we provide an overview of the use and potential use of these cells clinically, highlighting their potential as tools in an array of settings.

TGF-β favors bone marrow-derived dendritic cells to acquire tolerogenic properties

Dendritic cells (DCs) are the most powerful antigen-presenting cells that have an important role in the immunity and immune tolerance. Transforming growth factor β (TGF-β) is a pleiotropic cytokine widely expressing in various tissues and cells, which regulates cellular proliferation, differentiation and apoptosis of several immune cells and is considered to be a key factor in inducing immune tolerance. The effect of TGF-β on DCs is very complex. In this study, we further investigated the effect of TGF-β on inducing immune tolerance of DCs. DCs were differentiated from mice bone marrow cells in the absence or presence of TGF-β. The phenotype as well as function was studied in detail. We found that TGF-β limited the expression of CD40, CD83, CD86 and MHCII in DCs, increased CD45RB and indoleamine 2, 3-dioxygenase (IDO) expression in DCs, promoted IL-10 and limited IL-12 secretion by DCs. Moreover, TGF-β increased the endocytosis ability of DCs and limited the ability of DCs in activating T cells. These results suggest that TGF-β affects the immunity of DCs and enhances their tolerogenicity.