Identification and function analysis of ras-related nuclear protein from Macrobrachium rosenbergii involved in Spiroplasma eriocheiris infection.

A ras-related nuclear protein (Ran) protein was obtained from Macrobrachium rosenbergii, named MrRan. Phylogenetic analysis results showed that MrRan was clustered in one group together with other crustaceans. Tissue distribution analysis revealed that MrRan was expressed mainly in gill, intestine and stomach, and expressed weakly in muscle. The MrRan expression levels in gill and hemocyte of prawns were significantly up-regulated after challenged by Spiroplasma eriocheiris. The copy number of S. eriocheiris in MrRan dsRNA injection group was significantly less than control groups during infection. Meanwhile, silencing MrRan obviously increased the survival rate of prawns. The subcellular localization experiment suggested that recombinant MrRan was mainly located in the nucleus, and relatively weak in the cytoplasm. Finally, over-expression in Drosophila S2 cell indicated that MrRan could increase copies of S. eriocheiris and decrease of cell viability. The present study suggested that MrRan participated in regulating the phagocytosis of S. eriocheiris in M. rosenbergii.

Comparison of immune response of Pacific white shrimp, Litopenaeus vannamei, after multiple and single infections with WSSV and Vibrio anguillarum.

Our previous study demonstrated that Pacific white shrimp (Litopenaeus vannamei) infected by multiple pathogens showed higher mortality and death occurred more quickly than those infected by a single pathogen (Jang et al., 2014). For better understanding the defense mechanism against white spot syndrome virus (WSSV) and Vibrio anguillarum, immune responses of shrimp were evaluated in this study. The mRNA expression levels of five immune-related genes were analyzed by quantitative reverse real-time PCR, which included proPO-activating enzyme 1 (PPAE1), PPAE2, proPO activating factor (PPAF), masquerade-like serine proteinase (Mas) and ras-related nuclear gene (Ran). Results demonstrated that the transcription was suppressed more intensively in the multiple infection group than those in single infection groups. The transcriptional suppression was directly related to the higher mortality. The hypoimmunity could benefit pathogen invasion, replication and release of toxin in vivo. Results in this study will help to understand immune defense mechanism after shrimp were infected by multiple pathogens in aquaculture.

Ran overexpression leads to diminished T cell responses and selectively modulates nuclear levels of c-Jun and c-Fos.

Ras-related nuclear protein (Ran) is a Ras family GTPase, and its documented functions are the regulation of DNA replication, cell cycle progression, nuclear structure formation, RNA processing and exportation, and nuclear protein importation. In this study, we performed detailed mapping of Ran expression during mouse ontogeny using in situ hybridization. High Ran expression was found in various organs and tissues including the thymus cortex and spleen white pulp. Ran was induced in T cells 24 h after their activation. The function of Ran in the immune system was investigated using Ran transgenic (Tg) mice. In Ran Tg T cells, there was compromised activation marker expression, lymphokine secretion, and proliferation upon T cell receptor activation in vitro when compared with wild type T cells. Tg mice also manifested defective delayed type hypersensitivity in vivo. Upon PMA and ionomycin stimulation, Tg T cells were defective in nuclear accumulation of AP-1 factors (c-Jun and c-Fos) but not NF-kappaB family members. Our experiments showed that Ran had important regulatory function in T cell activation. One of the possible mechanisms is that intracellular Ran protein levels control the nuclear retention for selective transcription factors such as c-Jun and c-Fos of AP-1, which is known to be critical in T cell activation and proliferation and lymphokine secretion.

Molecular characterization of Ran gene up-regulated in large yellow croaker (Pseudosciaena crocea) immunity.

RanGTPase, one family of small G protein superfamily, has been widely demonstrated to be involved in transport system between cytoplasm and nucleus. However the knowledge about the function of RanGTPase in immunity remains limited. In this report, Ran gene (named LycRan) cDNA was cloned from the large yellow croaker, Pseudosciaena crocea, a marine fish. The full-length cDNA of LycRan was of 1033 bp, including a 5'-terminal untranslated region (UTR) of 43 bp, 3'-terminal UTR of 338 bp and an open reading frame (ORF) of 648 bp encoding a polypeptide of 216 amino acids. The deduced protein is highly homologous, it shares 90.74%, 88.89%, 89.35% and 85.20% identities with those of salmon, frog, human and fruit fly respectively. RT-PCR analysis indicated that LycRan gene was constitutively expressed in 9 tissues examined, including kidney, liver, gill, muscle, spleen, skin, heart, intestine and blood. The result of quantitative Real-Time RT-PCR analysis revealed the highest expression in kidney and the weakest expression in skin. Time course analysis showed that LycRan expression was obviously up-regulated in kidney, blood and spleen after immunization with either poly I:C or formalin-inactive Gram-negative bacterium Vibrio parahaemolyticus. It indicated that the highest expression was 2.8 times (at 48 h) as much as that in the control in the kidney (p < 0.05) challenged by poly I:C and 3.2 times (at 24 h) in the blood (p < 0.05) challenged by bacteria. These results suggested that LycRan might play an important role in large yellow croaker defense against the pathogen infection. Our study, therefore, might provide a clue to elucidate the large yellow croaker innate immunity.

High association of MOG-IgG antibodies in children with bilateral optic neuritis.

BACKGROUND: Bilateral optic neuritis (bilON) is a rare clinical presentation often thought to be associated with relapsing disorders such as neuromyelitis optica spectrum disorders (NMOSD) or multiple sclerosis (MS). OBJECTIVE: To characterize the clinical, radiological phenotype and antibody status of children presenting with bilON. MATERIAL AND METHODS: Retrospective multicenter study on children with bilON age <18 years with a first episode aquired demyelinating syndrome (ADS), cMRI, AQP4- and serum MOG-antibody status and follow-up data were collected. RESULTS: 30 patients (f:m = 15:15, median age 8.0y) with bilON met the inclusion criteria. 22/30 (73%) were MOG-positive (median: 1:1280, range: 1:160-1:1520). No patient showed AQP4-abs. 4/30 patients (13%), all with high MOG-abs titers, had recurrent episodes. No patient developed MS. Improvement after IVMP was observed in most patients (26/30; 87%). Outcome was favorable with no sequelae in 22/30 patients. Serial MOG-abs titers tested in 15/22 patients decreased to a median of 1:160 (range: 0-1:640) over a period of 31 months (range: 2-141 months) in 14/15 (93%) patients. MR imaging showed a predominantly anterior affection of the visual system in seropositive patients with bilateral intraorbital lesions in 68% (15/22), compared to 25% in MOG-negative patients (2/8). CONCLUSION: Pediatric bilON is associated with high MOG-abs titers in combination with anterior involvement of the visual system. Despite severe loss of vision, the majority of patients shows distinct recovery after IVMP.

Identification and modification of an HLA-A*0201-restricted cytotoxic T lymphocyte epitope from Ran antigen.

Ran is considered to be a promising target for tumor-specific immunotherapy because its protein is exclusively expressed in tumor tissues, though its mRNA can be expressed in most normal tissues. In our study, we obtained four candidate wild-type epitopes designated Ran1, Ran2, Ran3, and Ran4, derived from the Ran antigen with the highest predicted affinity with MHC-I, indicated by affinity prediction plots and molecular dynamics simulation. However, in vitro affinity assays of these epitopes showed only a moderate affinity with MHC-I. Thus, we designed altered peptide ligands (APLs) derived from Ran wild-type epitopes with preferred primary and auxiliary HLA-A*0201 molecule anchor residue replacement. Of the eight tested peptides, the 1Y analog had the strongest binding-affinity and lowest-dissociation rate to HLA-A*0201. Additionally, we investigated the CTLs activities induced by Ran wild-type peptides and the APLs in human PBMCs and in HLA-A*0201/K(b) transgenic mice. Ran1 1Y was superior to other APLs and wild-type peptides in eliciting epitope-specific CTL immune responses both in vitro and in vivo. In summary, a wild-type epitope of the tumor-specific antigen Ran, expressed broadly in many tumors, was identified and designated Ran1. An APL of Ran1, Ran1 1Y, was further designed and verified in vitro and in vivo and found to elicit a stronger Ran-specific CTL response, indicating a potential anti-tumor application in the future.

Xpo7 is a broad-spectrum exportin and a nuclear import receptor.

Exportins bind cargo molecules in a RanGTP-dependent manner inside nuclei and transport them through nuclear pores to the cytoplasm. CRM1/Xpo1 is the best-characterized exportin because specific inhibitors such as leptomycin B allow straightforward cargo validations in vivo. The analysis of other exportins lagged far behind, foremost because no such inhibitors had been available for them. In this study, we explored the cargo spectrum of exportin 7/Xpo7 in depth and identified not only ∼200 potential export cargoes but also, surprisingly, ∼30 nuclear import substrates. Moreover, we developed anti-Xpo7 nanobodies that acutely block Xpo7 function when transfected into cultured cells. The inhibition is pathway specific, mislocalizes export cargoes of Xpo7 to the nucleus and import substrates to the cytoplasm, and allowed validation of numerous tested cargo candidates. This establishes Xpo7 as a broad-spectrum bidirectional transporter and paves the way for a much deeper analysis of exportin and importin function in the future.

Ran, a small GTPase gene, encodes cytotoxic T lymphocyte (CTL) epitopes capable of inducing HLA-A33-restricted and tumor-reactive CTLs in cancer patients.

PURPOSE: The purpose is to identify a gene coding for tumor-associated antigen and peptide capable of inducing CTLs reactive to tumor cells with a HLA-A33-restricted fashion to provide scientific basis for specific immunotherapy to HLA-A33+ cancer patients. EXPERIMENTAL DESIGN: An expression gene-cloning method was used to identify the tumor-associated antigen gene. Northern blot analysis and immunohistochemistry were used to examine the mRNA and protein expression levels in various cells and tissues, respectively. Synthetic peptides were examined for their ability to induce HLA-A33+ tumor-reactive CTLs in peripheral blood mononuclear cells from cancer patients. RESULT: A gene of small GTPase, Ran, which controls the cell cycle through the regulation of nucleocytoplasmic transport, mitotic spindle organization, and nuclear envelope formation, was found to encode epitopes recognized by the HLA-A33-restricted CTLs established from T cells infiltrating into gastric adenocarcinoma. The expression of the Ran gene was increased in most cancer cell lines and cancer tissues at both the mRNA and protein levels. However, it was not enhanced in the surrounding normal cells or tissues. It was also undetectable in normal tissues as far as tested. Ran-derived peptides at positions 48-56 and 87-95 could induce CD8+ peptide-specific CTLs reactive to tumor cells from HLA-A33+ epithelial cancer patients in a HLA class I-restricted manner. CONCLUSIONS: Because of its increased expression in cancer cells and involvement in malignant transformation and/or the enhanced proliferation of cancer cells, the two Ran-directed peptides could be potent candidates in use for specific immunotherapy against HLA-A33+ epithelial cancers.

The involvement of Ran GTPase in lipopolysaccharide endotoxin-induced responses.

By functional cloning, we have established that Ran GTPase is involved in LPS-induced signal transduction. This has been accomplished by several functional comparisons of the two cDNAs, Lps(n)/Ran (or RanT/n) and Lps(d)/Ran (or RanC/d), which were isolated from cDNA libraries of LPS responder and hyporesponder mice, respectively. The letter n refers to the "normal" phenotype and the letter d refers to the "deficient" phenotype. Consistent with our previous results, more animal studies indicated that adenoviral transduction of RanC/d cDNA, but not RanT/n cDNA, into sensitive mice conferred significant resistance against endotoxin challenge. Thus the incorporation of RanC/d cDNA into gene therapy protocols as a therapeutic sequence remains very attractive. At steady state, hematopoietic cells transduced with RanC/d cDNA led to about a 10-fold increase in exogenous Ran protein compared with RanT/n cDNA. Furthermore, our cumulative data suggest that a slight elevation of Ran protein in B cells enhances LPS responsiveness, but the same elevation of Ran in macrophages does not. On the other hand, a high level of overexpression of Ran in both macrophages and B cells down-regulates LPS signal transduction. Thus LPS-induced signal transduction in macrophages and B cells is likely to occur via different signaling pathways.

Identification of immunogenic antigens using a phage-displayed cDNA library from an invasive ductal breast carcinoma tumour.

The identification of immunogenic antigens for serological testing and vaccine development is a major challenge facing cancer immunology research. To study the humoral immune response in patients with breast cancer, a T7 phage display cDNA library from an invasive ductal breast carcinoma was panned on patient serum IgG antibodies. By monitoring the selection with an immunoscreening technique, positive phage-displayed cDNA products reacting with breast cancer patient IgG antibodies were selected. Sequence analysis identified immunogenic antigens such as the cytochrome oxidase I, sp100 and Ran GTPase activating protein. Additionally, immunogenic uncharacterized gene products were also identified. Both the known and unknown immunoselected gene products should offer an additional source for cancer gene discovery for diagnostic testing and vaccine development.

Involvement of Ran in the regulation of phagocytosis against virus infection in S2 cells.

Phagocytosis plays important roles in innate and adaptive immunity in animals. Some small G proteins are found to be related to phagocytosis. However, the Ran GTPase has not been intensively characterized in immunity. In this paper, the sequence analysis showed that the Ran was highly conserved in animals, suggesting that its function was preserved during animal evolution. The results showed that Ran was upregulated in S2 cells in response to DCV infection. It was further revealed that the antiviral phagocytosis could be mediated by Ran in S2 cells. By comparison with the early marker and late marker of phagosomes, the results showed that the Ran protein played an essential role at the early stage of phagocytosis or throughout the entire phagocytic process. Therefore our findings enlarged our limited knowledge about the phagocytosis regulation by small G proteins concerning to the nucleus.

Characterization of myosin light chain gene up-regulated in the large yellow croaker immunity by interaction with RanGTPase.

RanGTPases are highly conserved in eukaryotes from yeast to human and have been implicated in many aspects of nuclear structure and function. In our previous study, it was revealed that the RanGTPase was up-regulated in large yellow croaker challenged by pathogen. However, the mechanism of RanGTPase in immunity remains unclear. In this investigation, on the basis of protein interaction, it was found that RanGTPase interacted with myosin light chain (designated as LycMLC), a crucial protein in the process of phagocytosis. Furthermore, it was found and characterized in this marine fish for the first time. The full-length cDNA of LycMLC was 771bp, including a 5'-terminal untranslated region (UTR) of 36bp, 3'-terminal UTR of 279bp and an open reading frame (ORF) of 456bp encoding a polypeptide of 151 amino acids. RT-PCR analysis indicated that LycMLC gene was constitutively expressed in the 9 tissues examined, including kidney, liver, gill, muscle, spleen, skin, heart, intestine and blood. The result of quantitative real-time PCR analysis revealed the highest expression in muscle and the weakest expression in skin. Time course analysis showed that LycMLC expression was obviously up-regulated in blood after immunization with either poly I:C or formalin-inactive Gram-negative bacteria Vibrio parahaemolyticus. It indicated that the highest expression was 4.5 times (at 24h) as much as that in the control (P<0.05) challenged by poly I:C and 5.0 times (at 24h) challenged by bacteria. These results suggested that LycMLC might play an important role in large yellow croaker defense against the pathogen infection. Therefore our study revealed a novel pathway concerning immunity of RanGTPase by the direct interaction with the cytoskeleton protein, which would help to better understand the molecular events in immune response against pathogen infection in fish.

The neuropathic potential of anti-GM1 autoantibodies is regulated by the local glycolipid environment in mice.

Anti-GM1 ganglioside autoantibodies are used as diagnostic markers for motor axonal peripheral neuropathies and are believed to be the primary mediators of such diseases. However, their ability to bind and exert pathogenic effects at neuronal membranes is highly inconsistent. Using human and mouse monoclonal anti-GM1 antibodies to probe the GM1-rich motor nerve terminal membrane in mice, we here show that the antigenic oligosaccharide of GM1 in the live plasma membrane is cryptic, hidden on surface domains that become buried for a proportion of anti-GM1 antibodies due to a masking effect of neighboring gangliosides. The cryptic GM1 binding domain was exposed by sialidase treatment that liberated sialic acid from masking gangliosides including GD1a or by disruption of the live membrane by freezing or fixation. This cryptic behavior was also recapitulated in solid-phase immunoassays. These data show that certain anti-GM1 antibodies exert potent complement activation-mediated neuropathogenic effects, including morphological damage at living terminal motor axons, leading to a block of synaptic transmission. This occurred only when GM1 was topologically available for antibody binding, but not when GM1 was cryptic. This revised understanding of the complexities in ganglioside membrane topology provides a mechanistic account for wide variations in the neuropathic potential of anti-GM1 antibodies.

New peptide vaccine candidates for epithelial cancer patients with HLA-A3 supertype alleles.

We previously identified 2 cancer-associated antigens, immediate early response gene X-1 (IEX) and small GTPase (Ran), and their 5 epitopes using human leukocyte antigen (HLA)-A33-restricted and tumor-infiltrating T cells from a colon cancer patient. In this study, we examined whether or not these peptides can induce cytotoxic T lymphocytes (CTLs) in HLA-A11+ or HLA-A31+ epithelial cancer patients because the HLA-A11, HLA-A31, and HLA-A33 alleles share binding motifs as an HLA-A3 supertype family, which is widely distributed in many ethnic populations. Among them, the 2 peptides, IEX 47-56 and IEX 61-69, induced peptide-specific CTLs from peripheral blood mononuclear cells of cancer patients with the HLA-A11 and HLA-A31 alleles more efficiently than the other 3 peptides. Antibody blocking and cold inhibition experiments revealed that the cytotoxicity of peptide-induced CTLs against cancer cells was attributable to peptide-specific and CD8+ T cells. Together with our previous findings, these results indicate that the 2 IEX peptides could be appropriate vaccine candidates for HLA-A11, HLA-A31, and HLA-A33 positive epithelial cancer patients. This information could expand the chance of a peptide-based cancer vaccine for epithelial cancer patients of many ethnic populations.

Regulated Ran-binding protein 1 activity is required for organization and function of the mitotic spindle in mammalian cells in vivo.

Ran-binding protein (RanBP) 1 is a major regulator of the Ran GTPase and is encoded by a regulatory target gene of E2F factors. The Ran GTPase network controls several cellular processes, including nucleocytoplasmic transport and cell cycle progression, and has recently also been shown to regulate microtubule nucleation and spindle assembly in Xenopus oocyte extracts. Here we report that RanBP1 protein levels are cell cycle regulated in mammalian cells, increase from S phase to M phase, peak in metaphase, and abruptly decline in late telophase. Overexpression of RanBP1 throughout the cell cycle yields abnormal mitoses characterized by severe defects in spindle polarization. In addition, microinjection of anti-RanBP1 antibody in mitotic cells induces mitotic delay and abnormal nuclear division, reflecting an abnormal stabilization of the mitotic spindle. Thus, regulated RanBP1 activity is required for proper execution of mitosis in somatic cells.