Zhijia Ni

Dendritic cells transduced with SOCS1 gene exhibit regulatory DC properties and prolong allograft survival.

SOCS1 is a key regulator of cytokine signaling and is important for maintaining balance in the immune system. It is thought to participate in negative feedback loops in cytokine signaling and may be an important signal for the regulation of dendritic cell (DC) maturation. However, it remains unclear whether DCs transduced with SOCS1 exhibit characteristics of regulatory DCs and induce allogeneic T-cell hyporesponsiveness. In this study, we constructed adenoviral vector coding SOCS1 (Ad-SOCS1) that can efficiently increase SOCS1 gene expression in bone marrow-derived dendritic cells. DCs transduced with Ad-SOCS1 (DC-SOCS1) expressed low levels of costimulatory and MHC molecules, were resistant to maturation and activation stimulation, induced allogeneic T-cell hyporesponsiveness, and promoted the generation of regulatory-like T cells in vitro. DC-SOCS1 pretreatment significantly prolonged the survival of allografts and led to a substantial increase in the generation of regulatory T cells. Our data suggest that SOCS1 inhibits DC maturation and induces regulatory DC generation, therefore possessing therapeutic potential to prevent rejection in organ transplantation.

Complement C3 deficiency prevent against the onset of streptozotocin-induced autoimmune diabetes involving expansion of regulatory T cells

Recent studies have demonstrated that complement contributes to the development of autoimmune diabetes. However, the mechanisms remain unknown. Herein, using a model of streptozotocin (STZ)-induced diabetes, we found the presence of immune tolerance to self islet in complement C3-deficient mice after STZ. Higher number of CD4+CD25+ regulatory T cells (Tregs) with characteristics of expressing Foxp3 was observed in C3-/- mice. These C3-/- Tregs exhibited enhanced suppressive capacity to effector cell proliferation. The central role of Tregs was further evidenced by that depleting these cells using anti-CD25 antibody dramatically abrogated the preventive effects of C3 deficiency on STZ-induced diabetes. Importantly, transforming growth factor-β (TGF-β) was a key factor for Treg-mediated immune suppression as blocking TGF-β activity reversed suppressive capacity of Tregs in vitro and diabetes-resistant effects of C3 deficiency in vivo. These findings suggest that resistance to overt diabetes in STZ-treated C3-/- mice involves a population of Tregs in TGF-β-dependent manner.

Adjuvant treatment suppresses IL-17 production by T cell-independent myeloid sources in nonobese diabetic mice.

Recent studies have shown that Th17 cells, as a distinct lineage from Th1 and Th2 subsets, play an obligatory role in the pathogenesis of autoimmune diseases. It is well known that immunotherapy with Complete Freunds adjuvant (CFA) is effective in preventing from the onset of autoimmune diabetes in nonobese diabetic (NOD) mice. In the present study, we investigated whether CFA treatment restrained Th17 development and down-regulated Th17-related cytokine production in NOD mice. Th17-related cytokines (i.e. IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-6, TGF-beta) production in splenocytes was decreased dramatically on day 18 following CFA immunization. This effect was also observed at 10 and 20 week after adjuvant treatment. Injection of IL-17 into CFA-treated diabetes-free mice led to occurrence of overt diabetes, indicating that therapeutic effects of adjuvant treatment may be partially due to suppressing Th17 commitment. Interestingly, the main producer of IL-17 resided in a population of myeloid cells, which negatively expressed makers of neutrophil or macrophages. IL-23 stimulation did not alter the distribution of IL-17 in myeloid cells. Furthermore, this pattern of IL-17 expression was also present in Balb/c and C57BL/6 strains. These findings may have important implications for understanding of mechanisms underlying adjuvant treatment on autoimmune diseases.

Suppression of Allograft Rejection by Tim-1-Fc through Cross-Linking with a Novel Tim-1 Binding Partner on T Cells

Engagement of T-cell immunoglobulin mucin (Tim)-1 on T cells with its ligand, Tim-4, on antigen presenting cells delivers positive costimulatory signals to T cells. However, the molecular mechanisms for Tim-1-mediated regulation of T-cell activation and differentiation are relatively poorly understood. Here we investigated the role of Tim-1 in T-cell responses and allograft rejection using recombinant human Tim-1 extracellular domain and IgG1-Fc fusion proteins (Tim-1-Fc). In vitro assays confirmed that Tim-1-Fc selectively binds to CD4+ effector T cells, but not dendritic cells or natural regulatory T cells (nTregs). Tim-1-Fc was able to inhibit the responses of purified CD4+ T cells that do not express Tim-4 to stimulation by anti-CD3/CD28 mAbs, and this inhibition was associated with reduced AKT and ERK1/2 phosphorylation, but it had no influence on nTregs. Moreover, Tim-1-Fc inhibited the proliferation of CD4+ T cells stimulated by allogeneic dendritic cells. Treatment of recipient mice with Tim-1-Fc significantly prolonged cardiac allograft survival in a fully MHC-mismatched strain combination, which was associated with impaired Th1 response and preserved Th2 and nTregs function. Importantly, the frequency of Foxp3+ cells in splenic CD4+ T cells was increased, thus shifting the balance toward regulators, even though Tim-1-Fc did not induce Foxp3 expression in CD4+CD25− T cells directly. These results indicate that Tim-1-Fc can inhibit T-cell responses through an unknown Tim-1 binding partner on T cells, and it is a promising immunosuppressive agent for preventing allograft rejection.

A bioengineered drug-Eluting scaffold accelerated cutaneous wound healing In diabetic mice

Hyperglycemia in diabetic patients can greatly hinder the wound healing process. In this study we investigated if the engagement of F4/80(+) murine macrophages could accelerate the cutaneous wound healing in streptozotocin induced diabetic mice. To facilitate the engagement of macrophages, we engineered a drug-eluting electrospun scaffold with a payload of monocyte chemoattractant protein-1 (MCP-1). MCP-1 could be readily released from the scaffold within 3 days. The electrospun scaffold showed no cytotoxic effects on human keratinocytes in vitro. Full-thickness excisional cutaneous wound was created in diabetic mice. The wound fully recovered within 10 days in mice treated with the drug-eluting scaffold. In contrast, the wound took 14 days to fully recover in control groups. The use of drug-eluting scaffold also improved the re-epithelialization. Furthermore, we observed a larger population of F4/80(+) macrophages in the wound bed of mice treated with drug-eluting scaffolds on day 3. This marked increase of macrophages in the wound bed could have contributed to the accelerated wound healing. Our study shed new light on an immuno-engineering solution for wound healing management in diabetic patients.

The therapeutic effect of monocyte chemoattractant protein-1 delivered by an electrospun scaffold for hyperglycemia and nephrotic disorders

Here, we investigated in diabetic mice the therapeutic effect of monocyte chemoattractant protein-1 (MCP-1), locally delivered by an electrospun scaffold, on transplanted islets. This therapeutic scheme is expected to exert a synergistic effect to ameliorate hyperglycemia and its associated nephrotic disorders. The cumulative amount of MCP-1 released from the scaffold in vitro within a 3-week window was 267.77±32.18 ng, without a compromise in bioactivity. After 8 weeks following the transplantation, the islet population stimulated by MCP-1 was 35.14%±7.23% larger than the non-stimulated islet population. Moreover, MCP-1 increased concentrations of blood insulin and C-peptide 2 by 49.83%±5.29% and 43.49%±9.21%, respectively. Consequently, the blood glucose concentration in the MCP-1 group was significantly lower than that in the control group at week 2 post-surgery. MCP-1 also enhanced the tolerance of sudden oral glucose challenge. The rapid decrease of blood creatinine, urine creatinine, and blood urea nitrogen suggested that the recovery of renal functions compromised by hyperglycemia could also be attributed to MCP-1. Our study shed new light on a synergistic strategy to alleviate hyperglycemia and nephrotic disorders in diabetic patients.

Validation of a criteria-specific long-term survival prediction model for hepatocellular carcinoma patients after liver transplantation.

The aim of this study was to validate a criteria-specific long-term survival prediction model (MHCAT) in a large cohort of hepatocellular carcinoma (HCC) patients after liver transplantation (LT) in China. Independent risk factors in MHCAT were retrospectively analysed for HCC patients recorded in the China Liver Transplant Registry. Survival predictions for each patient were calculated using MHCAT scores and the Metroticket formula separately, and the prediction efficacy of MHCAT and Metroticket was compared using the area under ROC curve (c-statistic). A total of 1371 LTs for HCC were analysed in the study, with a median follow-up of 22.2 months (IQR 6.1–72.4 months). The proportions meeting the Milan, UCSF, Fudan and Hangzhou criteria were 34.4%, 39.7%, 44.2% and 51.9%, respectively. The c-statistics for MHCAT predictions of 3- and 5-year survival rates of HCC recipients were 0.712–0.727 and 0.726–0.741, respectively. Among these patients, 1298 LTs for HCC were ultimately selected for the comparison analysis for prediction efficacy. The c-statistic of MHCAT for predictions of 3-year survival with reference to the Milan, UCSF and Fudan criteria was significantly increased compared with that for Metroticket (p < 0.05). In conclusion, MHCAT can effectively predict long-term survival for HCC recipients after LT.

Favorable effect of thrombocytopenia on outcomes of liver transplantation for hepatocellular carcinoma

Platelets may affect tumor cell proliferation and angiogenesis by releasing several cytokines including plateletderived growth factor and vascular endothelial growth factor, among others. [1] Studies have shown that the platelet count (PLT) is a risk factor for hepatic carcinogenesis. [2,3] Moreover, a recent meta-analysis by Pang et al. [4] indicated that preoperative thrombocytopenia was significantly associated with poor overall survival (OS) and recurrence-free survival (RFS) in patients with hepatocellular carcinoma (HCC). However, all studies included in that meta-analysis focused on HCC patients treated with hepatectomy or radiofrequency ablation, without addressing patients treated with liver transplantation (LT). We therefore aimed to evaluate the efficacy of the PLT in predicting outcomes of HCC patients undergoing LT. The medical records of 402 HCC patients who underwent LT at our transplant center between 2001 and 2012 were retrospectively reviewed. This study was approved by the Research Ethics Committee of Changzheng Hospital. PLT absolute values were taken the day before surgery. Patient characteristics are reported in Table 1. There was a predominance of hepatitis B virus-related HCC (n1⁄4380, 94.5%), and 263 patients (65.4%) did not satisfy the Milan criteria. The mean PLT was 103 10/L. Using the Martingale residuals of the Cox model, we classified patients into three categories according to the PLT:565, 65–130 and4130 ( 10/L). Kaplan–Meier survival curves indicated that patients with a low PLT had better OS (Figure 1a) and RFS (Figure 1b). Furthermore, multivariate analysis by Cox proportional hazards regression indicated that a PLT565 10/L was independently associated with a favorable OS [hazard ratio, 0.549; 95% confidence interval (CI), 0.366–0.824; p1⁄40.004] and RFS (hazard ratio, 0.598; 95% CI, 0.407–0.879; p1⁄40.009). In addition, a significant correlation was detected between the PLT and tumor biology. Patients with a low PLT (5130 10/L) had less frequent vascular invasion (p1⁄40.033), lower levels of serum alpha-fetoprotein (AFP;5400 ng/mL, p50.001) and satisfied the preoperative Milan criteria more frequently (p50.001). In contrast to previous studies, [5,6] our findings showed a favorable outcome for HCC patients with preoperative thrombocytopenia after LT. There are several potential explanations. Thrombocytopenia is correlated with poor liver function and relevant portal hypertension, [7] contraindicating extensive hepatic resection as well as anatomical resection. [8] Thus, these potentially curative treatments might not lead to a cure in patients with thrombocytopenia. LT could cure not only the tumor, but also the underlying cirrhosis, and the effectiveness of LT is not affected by the degree of liver function impairment. [9] Our study showed that