Expression Pattern of Tumor Necrosis Factor-α-Induced Protein 8-Like 2 in Acute Rejection of Cardiac Allograft

BACKGROUND

Tumor necrosis factor-α-induced protein-8 like-2 (TIPE2) is a negative regulator of innate immunity and cellular immunity, yet the expression pattern of TIPE2 in acute rejection of cardiac allograft remain enigmatic.

METHODS

We developed cardiac transplantation models and divided into 3 groups: a naive group, a syngeneic group, and an allogeneic group. Then, we detected the messenger RNA and protein of TIPE2 in cardiac allografts. Real-time polymerase chain reaction showed expression of CD4 and CD8 in the donor heart, and immunofluorescence assay revealed the association between T cells and TIPE2.

RESULTS

In our study, we first found that the expression of TIPE2 in cardiac allografts is upregulated compared with the syngeneic control, and increases in a time-dependent manner. The immunocytochemistry of heart grafts revealed a strong expression of TIPE2 in the inflammatory cells, but not in the cardiomyocytes. Finally, we proved that CD4⁺ and CD8⁺ T cells infiltrated cardiac allografts abundantly, which express ample TIPE2.

CONCLUSIONS

The upregulated expression of TIPE2 in cardiac allografts, mainly came from T cells, which infiltrated the donor heart. This finding indicates that there may be an association between TIPE2 and acute cardiac allograft rejection.

[Effect of Six1,TGF-β,VEGF-C that promoting tumor lymphangiogenesis in human laryngeal carcinoma xenografts in nude mice]

Objective:To research the effect of Six1,TGF-β,VEGF-C that promoting tumor lymphangiogenesis in human laryngeal carcinoma xenografts in nude mice. Method:Technology of RNA interference was used for silencing Six1 and TGF-β genes expression in laryngeal squamous cell, preparation Six1-targeting and TGF-β-targeting siRNA for transfecting into laryngeal squamous cell carcinoma, sieve out positive clone cell and amplify. Preparing bearing cancer mice, the mice were divided into five groups, group A (untransfected),group B(empty vector), group C(Six1-siRNA),group D(TGF-β-siRNA),group E(Six1+TGF-β-siRNA). 6-12mm when the tumor has grown, the mice were sacrificed by cervical. The size of each tumor and metastasis were observed and recorded.The protein expression of Six1,TGF-β and VEGF-C was determined by immunohistochemistry and Western blot.The mRNA of Six1,TGF-β and VEGF-C was determined by RT-PCR. Result:The average tumor volume and the number of metastasis cases in group B have no statistically significant compared with group A. The average tumor volume in group C, group D and group E has no significantly reduced, but there is a clear reduction of the number of metastasis cases compared with group A. The average tumor volume and number of metastasis cases in group E has no significantly reduced compared with group C and group D. Both protein and mRNA expression of Six1, TGF-β and VEGF-C in group B had no significant difference compared with group A. In group C, group D and group E,both protein and mRNA expression of VEGF-C was decreased,difference has statistically significant compared with group A. Both protein and mRNA expression of VEGF-C in group E had no significant difference compared with group C and group D. Conclusion:Both Six1 and TGF-β can mediate tumor lymphangiogenesis and lymph node metastasis by mediate the expression of VEGF-C. Suggest that Six1,TGF-β might be a potential therapeutic target for preventing lymph node metastasis of tumor.

Dysregulation of Bmi1 promotes malignant transformation of hepatic progenitor cells

Adult hepatic progenitor cells (HPCs) are involved in a wide range of human liver diseases, including hepatocellular carcinoma (HCC). Bmi1 has been reported to have vital roles in stem cell self-renewal and carcinogenesis. We have previously demonstrated that Bmi1 is upregulated in HCC with bile duct tumor thrombi, a subtype of HCC characterized by profuse expression of hepatic stem cell markers. However, the function of Bmi1 in HPCs has not yet been well elucidated. The current study was designed to investigate the effects of Bmi1 on the biological properties of rat HPCs. To accomplish this, Bmi1 was silenced or enhanced in two HPC cell lines (WB-F344 and OC3) by, respectively, using either small interfering RNA against Bmi1 or a forced Bmi1 expression retroviral vector. The biological functions of Bmi1 in HPCs were investigated through cell proliferation assays, colony-formation assays, cell cycle analysis and invasion assays, as well as through xenograft-formation assays. In this study, genetic depletion of Bmi1 repressed cell proliferation, colony formation and invasion in both assessed HPC cell lines relative to controls. Conversely, forced expression of Bmi1 in two HPCs cell lines promoted cell proliferation, colony formation and invasion in vitro. Aldehyde dehydrogenase (ALDH) assay revealed a significant increase in the number of ALDH-positive cells following the forced expression of Bmi1 in HPCs. Most importantly, transplantation of forced Bmi1 expression HPCs into nude mice resulted in the formation of tumors with histological features of poorly differentiated HCC. Taken together, our findings indicate that forced expression of Bmi1 promotes the malignant transformation of HPCs, suggesting Bmi1 might be a potential molecular target for the treatment of HCC.

Expression of exogenous NF-IL6 induces apoptosis in Sp2/0-Ag14 myeloma cells

NF-IL6 (or C/EBP beta) is a multifunctional transcription factor of the C/EBP family. To study the effects of exogenous expression of NF-IL6 on the growth of cells of hematopoietic tumors, we infected SP2/0-Ag14 myeloma cells with pLXSN recombinant retrovirus harboring the NF-IL6 cDNA. We found that the transfected cells revealed changes typical of the apoptosis and finally died. The expression of NF-IL6 protein was shown by a "supershift" assay in the NF-IL6-transfected cells. In controls, where cells were infected by the retroviral vector with a mutant NF-IL6 coding region as well as the vector without insert, no sign for expression of NF-IL6 and apoptosis was observed. Therefore, our work shows that the apoptosis of this myeloma cell line was induced by the exogenous NF-IL6 expression. This is significantly different from the apparent effects of NF-IL6 in leukemia cells and in fibroblasts. These facts indicate that NF-IL6 exerts different functions in different cell types. We discuss possible mechanisms for the NF-IL6-induced apoptosis.

[Changes of cytoplasmic calcium and magnesium concentration and calcium distribution in human platelets caused by thrombin]

Changes of calcium and magnesium concentration in human platelets during thrombin induced agglutination and the distribution of the respective concentration in the platelet population were measured by fluorescence probe using fura 2, mag-fura 2 and fluo 3. The cytoplasmic free calcium concentration increases with addition 2 thrombin. When the thrombin concentration was increased to 0.5 U/ml, the calcium concentration increase showed two rising peaks. The popular cytoplasmic calcium concentration in platelets shows normal distribution. The cytoplasmic free magnesium concentration also increases with increase of calcium concentration, showing that magnesium also plays a significant effect in the condensation of platelets.