K48- and K27-mutant ubiquitin regulates adaptive immune response by affecting cross-presentation in bone marrow precursor cells.

K48-linked ubiquitination determines antigen degradation and plays vital roles in the process of cross-presentation of bone marrow precursor cell (BMPC)-derived dendritic cells (DCs). Although previous studies revealed that K48 and K27-linked ubiquitination regulates innate immunity, the exact roles of K48 and K27-linked ubiquitination in cross-presentation and BMPC-based adaptive immunity are still uncertain. In this study, we investigated the effects of K48- and K27-mutant ubiquitin (Ub) on BMPC-based adaptive immune response by observing the effects of MG132, Ub deficiency, and K48/K27-mutant Ub on cross-presentation, T cell proliferation, IFN-γ secretion, BMPC-based CTL priming, and thereby the efficiency of cytolytic capacity of BMPC-activate T cells. We demonstrated that MG132, Ub deficiency, and K48-mutant Ub impair cross-presentation, T cell proliferation, IFN-γ secretion, BMPC-based CTL priming, and the cytolytic capacity of BMPC-activated T cells. Moreover, although K27-only Ub decreases cross-presentation, the replenishment of K27-mutant Ub restores Ub deficiency impaireds the abilities of T cell proliferation, IFN-γ secretion, CTL priming, and the cytolytic capacity of BMPC-activated T cells. Thus, these data suggest that K48- and K27-linked ubiquitination contributes to BMPC-mediated adaptive immune response by affecting BMPC cross-presentation and the cytolytic capacity by up-regulating both perforin and granzyme B in BMPC-activated T cells. K48- and K27-mutant Ub might have potential clinical therapeutic function in adaptive immune response-associated diseases.

Ex vivo IL-15 replenishment augments bone marrow precursor cell-mediated adaptive immunity via PI3K-Akt pathway.

This study tested the hypothesis that PI3K-Akt activity contributes to the superior immune function of IL-15-administrated bone marrow precursor cells (BMPC). Our previous studies revealed that PI3K-Akt play vital role in dendritic cells (DCs) cross-presentation and DC-based CTL priming. Despite the fact that IL-15 serves multiple functions in its therapeutic potential for the induction and maintenance of T cell response, the exact role of PI3K-Akt in IL-15 increased adaptive immunity is still poorly understood. In this study, we demonstrated that ex vivo IL-15 administration increased BMPC capability of antigen uptake and the expression of costimulatory molecules (such as CD80 and 4-1BB(CD137) ligand [4-1BBL]) and MHC class I molecule via PI3K-Akt pathway. Importantly, PI3K-Akt activity was not only necessary for IL-15 augmented BMPC cross-presentation and CTL priming, but also facilitated IL-15 increased therapeutic potential of the cytolytic capacity and maintenance of BMPC-activated T cells. Thus, these data suggested that PI3K-Akt activity contribute to the superior immune function of IL-15-administrated BMPC and thereby might be therapeutic potential for adaptive immunity.

TIPE attenuates the apoptotic effect of radiation and cisplatin and promotes tumor growth via JNK and p38 activation in Raw264.7 and EL4 cells.

Tumor necrosis factor α­induced protein 8 (TIPE) is highly expressed in many types of malignancies. Apoptosis is the process of programmed cell death which maintains the balance of cell survival and death. TIPE is involved in the carcinogenesis of many tumor types, yet the exact role of TIPE in defective apoptosis­associated carcinogenesis remains uncertain. In the present study, TIPE­overexpressing Raw264.7 and EL4 cells and vector control cells were treated with 4 mJ/cm2 ultraviolet radiation or 2 µg/ml cisplatin. Following ultraviolet irradiation, TIPE overexpression decreased the percentage of apoptotic cells as detected by flow cytometric and reversed the cisplatin­mediated decrease in mitochondrial membrane potential by JC­1 assay. Western blot analyses also revealed that TIPE overexpression inhibited cisplatin­induced activation of caspase­3 and ­9 and PARP. Secondly, TIPE overexpression increased the levels of phosphorylated JNK, MEK and p38. Moreover, inhibition of JNK and p38, but not MEK, efficiently abolished the cell pro­survival effect of TIPE. Most importantly, an in vivo tumor implantation model revealed that TIPE overexpression augmented the volume and weight of the implanted tumors, indicating that TIPE facilitated tumor formation. We found that TIPE exhibited an anti­apoptotic effect via JNK and p38 activation, which ultimately promoted tumor. Hence, the present study revealed that activation of JNK and p38 kinases contribute to the TIPE­mediated anti­apoptotic effect, indicating that JNK and p38 may be potential therapeutic molecules for TIPE overexpression­associated diseases.

[Research progress in kidney dendritic cells].

Kidney dendritic cells(DC) play important roles in the pathogenesis of kidney diseases. Kidney DC presents anti-inflammatory effects in certain kidney diseases, sometimes presents pro-inflammation in other diseases, and sometimes their effects are changing in different stages of the disease, suggesting that the differentiation and function of kidney DC may be influenced by microenvironment. This article reviews the origin and distribution of kidney DC subsets and their roles in the pathogenesis of kidney diseases such as lupus nephritis and pyelonephritis, and the functional regulation of kidney DC by proximal tubule epithelial cells.

[TcpC induces apoptosis of human vascular endothelial cells and its mechanisms].

OBJECTIVE: To investigate the effects of TcpC on human umbilical vascular endothelial cells (HUVECs) and its mechanisms. METHODS: HUVECs were co-cultured with TcpC secreting wild-type E. coli strain CFT073 (TcpC(wt)) or tcpc gene-deleted CFT073 mutant strain (TcpC(mut)) in transwell system,respectively. Apoptosis of HUVECs was analyzed by Annexin-V/PI double staining. Mitochondrial membrane depolarization was detected by JC-1 staining. Expression of apoptosis-related proteins in HUVECs was determined by Western blot. RESULTS: HUVECs showed morphological changes after co-cultured with TcpC(wt) for 24 h: the cells became detached and cell debris increased,and cell number was also decreased when compared to HUVECs co-cultured with TcpC(mut). The apoptosis of HUVEC cells co-cultured with TcpC(wt) for 24 h significantly increased,compared to that of control group and TcpC(mut) group (60.1% 9.7% compared with 9.0% 1.3% and 16.9% 0.4%,respectively, P<0.05); meanwhile the mitochondrial depolarization of HUVECs co-cultured with TcpC(wt) was significantly increased,compared to that in control and TcpC(mut) groups (64.5% 0.9% compared with 14.5% 2.1% and 15.6% 3.3%, respectively,P<0.05). Cleavage of PARP and inhibition of Mcl-1 and XIAP expression were seen in HUVECs co-cultured with TcpC(wt),but not in groups of control and TcpC(mut). CONCLUSION: TcpC secreted from CFT073 can induce apoptosis of HUVECs through mitochondrial pathway, in which PARP is cleaved and Mcl-1 and XIAP expressions are inhibited.

[Childhood-onset myasthenia gravis: the analysis of influencing factors of therapeutic effect and prognosis].

OBJECTIVE: Though myasthenia gravis (MG) is a typical autoimmune disorder, there was some controversy on the treatment of the childhood-onset MG. By observing the efficacy of different therapies, the authors analyzed the affecting factors of prognosis in childhood-onset MG. METHOD: The retrospective data of 155 patients with childhood-onset MG (age of MG onset was less than 15 years) were collected from Department of Neurology, Beijing Tongren Hospital (January 2000 - February 2010). The patients were non-randomly divided according to their treatment into 3 groups (glucocorticoid, thymectomy and glucocorticoid combined with thymectomy groups). Postintervention status meeting the criteria of Myasthenia Gravis Foundation of America (MGFA) "complete stable remission, CSR", "pharmacologic remission, PR", "minimal manifestations, MM", or "Improved, I" was regarded as desirable response, which was used as primary indicator of observation. The authors assessed the efficacy of three therapies and analyzed the influencing factors of prognosis by using Chi-square test and Logistic regression. RESULT: At 3 months of treatment, glucocorticoid group showed the highest effective rate. At the end of 1 year or 2 years of treatment, glucocorticoid combined with thymectomy group showed the highest effective rate respectively. The generalization rate of MG at 2 years, 10 years and 20 years in childhood-onset ocular MG patients were 4.3%, 10.7%, and 41.5%, respectively. Of patients with generalization of MG, 48.1% occurred within 2 years, 92.6% within 20 years. Univariate analysis showed that in childhood-onset ocular MG patients, variables such as age at onset (> 10 years), LG-MG and with chronic fatigue were significantly associated with general MG conversion. Whereas multivariate analysis showed that patients with age at onset (> 10 years) and chronic muscle fatigue were apt to convert to generalized MG. CONCLUSION: Glucocorticoid appeared to have an effect that leads to early remission of symptoms in childhood-onset MG patients and glucocorticoid combined with thymectomy appeared to have better long-term effect. For those childhood-onset ocular MG patients with longer course of disease, older age of onset, chronic fatigue, or LG-MG, physicians should try to prevent the generalization of MG by immunosuppressive therapies.