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Inflammatory response plays an important role in the pathogenesis of secondary damage after traumatic brain injury (TBI). The inflammasome is a multiprotein complex involved in innate immunity and a number of studies have suggested that the inflammasome plays a critical role in a host inflammatory signaling. Nucleotide-binding domain, leucine-rich repeat, pyrin domain containing 3 (NLRP3) is a key component of the NLRP3-inflammasome, which also includes apoptotic speck-containing protein (ASC) with a cysteine protease (caspase)-activating recruitment domain and pro-caspase1. Activation of the NLRP3-inflammasome causes the processing and release of the interleukin 1 beta (IL-1β) and interleukin 18 (IL-18). Based on this, we hypothesized that the NLRP3-inflammasome could participate in the inflammatory response following TBI. However, the expression of NLRP3-inflammasome in cerebral cortex after TBI is not well known. Rats were randomly divided into control, sham and TBI groups (including 6 h, 1 day, 3 day and 7 day sub-group). TBI model was induced, and animals were sacrificed at each time point respectively. The expression of NLRP3-inflammasome was measured by quantitative real-time polymerase chain reaction, western blot and immunohistochemistry respectively. Immunofluorescent double labeling was performed to identify the cell types of NLRP3-inflammasome's expression. Moreover, enzyme linked immunosorbent assay was used to detect the alterations of IL-1β and IL-18 at each time point post-injury. The results showed that, TBI could induce assembly of NLRP3-inflammasome complex, increased expression of ASC, activation of caspase1, and processing of IL-1β and IL-18. These results suggested that NLRP3-inflammasome might play an important role in the inflammation induced by TBI and could be a target for TBI therapy.

Despite numerous researches and improvements in the past few years, the precise mechanisms underlying secondary brain injury after trauma remain obscure. Iron is essential for almost all types of cells, including nerve cells. However, excess of iron has been proved to contribute to the brain injury following trauma in animal models. As a key iron-handling protein in the brain, ferritin might be involved in iron-induced pathophysiological process of various brain disorders. Therefore, the current study was aimed to investigate the expression of ferritin in the human contused brain. Nineteen contused brain samples were obtained from 19 patients undergoing surgery for brain contusions 3 h-17 d after trauma, and three normal temporal pole samples from 3 patients with petroclival meningioma were collected as controls. Expression of ferritin-H-chain was measured by quantitative real-time polymerase chain reaction (PCR), western blot and immunohistochemistry, respectively. Perl's reaction was taken for iron staining. The results showed that human traumatic brain injury (TBI) could up-regulate ferritin-H-chain in pericontusional cortex. A marked increase of ferritin was detected in the early group (≤12 h), and remained elevated for a long time till after 48 h post-injury. The location of ferritin-H-chain was found mainly at the neuron-like cells and seldom at glia-like cells. Perl's reaction showed that most of the iron-positive cells were glia-like cells. These findings suggested that iron and ferritin might be involved in the secondary brain injury and could be therapeutic targets for patients with TBI.

Development of a versatile mammalian display system is essential for the selection of functional human antibodies with high affinities. Here we described a novel strategy for rapid construction of full-length antibody libraries that could be efficiently expressed on mammalian cell surfaces. The universal vector pDGB-HC-TM was constructed by inserting multiple cloning site unique sequences recognized by restriction endonucleases BsmBI, SfiI, and BstXI for the pop-in and pop-out of genes of interest. Cytomegalovirus promoter, a commonly used promoter for high expression of proteins in a variety of mammalian cells, was used to drive expression of the inserted antibody genes and a transmembrane domain from platelet-derived growth factor receptor was fused in frame to the C-terminus of heavy chain consistent region to anchor the antibody expressed on the mammalian cell surface. Using this strategy, we constructed a full-length human antibody display library. DNA sequence analysis and expression analysis indicated that the library constructed had a combinatory expressible, detectable diversity of 6.58 x 10(10).

The display of full-length antibody on the cell surface was achieved by fusing a transmembrane domain of the platelet-derived growth factor receptor (PDGFR) to the C-terminus of the heavy chain constant region. We also incorporated a furin cleavage site between the constant region and PDGFR transmembrane domain to obtain secreted antibodies. As a result, antibodies can be expressed simultaneously on the cell surface in a membrane-anchored version for screening and selecting through fluorescence-activated cell sorting (FACS) analysis, as well as in conditioned medium in a secreted version for function analysis.

Background Traumatic brain injury (TBI) can cause gastrointestinal dysfunction and increase intestinal permeability. Nuclear factor kappa B (NF-κB) has been shown to be associated with these intestinal events, but it is not well known how NF-κB is activated in the intestine after TBI. Based on previous studies, we hypothesize that myeloid differentiation primary response protein 88 (Myd88) may have an important role in NF-κB activation in the intestine, which mediates the inflammation and ultimately results in acute intestinal mucosal injury. Methods We randomly divided adult male C57BL/6 mice into control groups and TBI groups at different time points. We induced a closed head injury model by weight drop (a 333-g metal rod dropping from a 2.5-cm height). We detected Myd88 protein level and NF-κB binding activity in ileum tissue by Western blot and electrophoretic mobility shift assay, respectively. Meanwhile, we detected the mRNA levels of Myd88, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and intercellular adhesion molecule-1 by real-time polymerase chain reaction. Results The Myd88 protein and mRNA levels, as well as NF-κB binding activity in the ileum tissue, significantly increased at 6 h after TBI, peaked at 3 d, and remained elevated by 5 d post-injury. The levels of TNF-α, IL-1β, and intercellular adhesion molecule-1 also remarkably increased after TBI. There was a positive relationship between the expression of Myd88 and that of NF-κB, TNF-α, and IL-1β. Conclusions Traumatic brain injury induced a rapid and persistent up-regulation of Myd88, NF-κB, and proinflammatory cytokines in the intestine. This up-regulation which might have an important role in the pathogenesis of acute intestinal mucosal injury.

To construct a rheumatoid arthritis-specific full-length fully human mammalian display antibody libraries.Peripheral blood lymphocytes were isolated from patients with rheumatoid arthritis. The repertoires of kappa light chain (LCκ) and heavy chain variable region (VH) of the antibodies were amplified by RT-PCR. The amplified LCκ and VH genes were inserted into the vector pDGB-HC-TM separately, and the ligated libraries were transformed into competent E.coli TOPO-10 strain to construct the rheumatoid arthritis-specific antibody heavy and light chain libraries. 293T cells were co-transfected with the libraries and the full-length fully human antibody expressed on the surface of 293T cells were analyzed by flow cytometry.The libraries of rheumatoid arthritis-specific antibody LCκ and heavy chain (IgG1) were constructed. The expression of full-length fully human antibody on the surface of 293T cells was confirmed by flow cytometry. With the rates of correct LCκ and heavy chain sequence insertion reaching 80% and 60%, respectively, as shown by DNA sequence analysis of the randomly selected clones, the libraries showed an expressible combinatory diversity of 6.13×10(10).The constructed libraries provide a useful platform for screening rheumatoid arthritis-specific antibodies.

To construct a mammalian cell surface display library of full-length human antibodies.The total RNA was isolated from human peripheral blood mononuclear cells (PBMCs), and the genes encoding the heavy chain variable regions and kappa light chains (VH and Cκ) of the antibodies were amplified by RT-PCR. The amplified VH and Cκ gene sequences were separately inserted into the vector pDGB-HC-TM. The ligation mixtures were transformed into competent E.coli DH5α cells to construct the antibody libraries, and the library sizes and diversity were analyzed. The library DNAs were transfected into CHO cells and the expression of the full-length human antibodies on the surface of CHO cells was analyzed by flow cytometry.The heavy chain gene library constructed showed a diversity of 2.6 × 10(5), and the kappa light chain gene library had a diversity of 2.0 × 10(5). Sequence analysis of 10 clones randomly selected from the constructed heavy chain gene library and 10 from the light chain gene library showed that 8 heavy chain clones and all 10 light chain clones contained correct open reading frames. Flow cytometry demonstrated that all the 18 clones expressed full-length antibodies, which could be detected on CHO cell surfaces. After co-transfection of the heavy chain and light chain gene libraries into CHO cells, the expression of full-length antibodies on CHO cell surfaces was detected with the positive cells reaching 31.5.A full-length human mammalian display antibody library with a combinatory diversity of 5.2 × 10(10) can be constructed in two weeks, which allows the display of full-length antibodies on mammalian cell surface.

A unique four-way ligation strategy was developed for rapid construction of a full-length antibody library. A mammalian expression vector was constructed that contained dual mammalian expression cassettes and sequences recognized by the unique restriction enzymes BsmBI, BstXI, and SfiI. Both full-length light-chain and variable domain of heavy-chain genes were inserted into the vector in one step by four-way ligation, and full-length bivalent antibodies were displayed on mammalian cell surfaces. Using this strategy, only 2 weeks were required to successfully construct high-quality, full-length human antibody libraries.

To construct human renal cell carcinoma patient-specific full-length antibody library using mammalian cell surface display technique.Peripheral blood mononuclear cells (PBMC) were isolated from patients with renal cell carcinoma. The repertoires of kappa light chain (LCkappa) and heavy chain variable region (VH) of antibody were amplified by RT-PCR. The LCkappa and VH libraries were inserted into the vector pDGB-HC-TM separately, and the ligated libraries were transformed into competent E.coli TOPO10 to construct the renal cell carcinoma patient-specific antibody heavy and light chain libraries. 293T cells were co-transfected with the libraries and the full-length human antibodies expressed on the surface of 293T cells were analyzed by flow cytometry.The libraries of renal cell carcinoma-specific antibody kappa light chain (LCkappa) and heavy chain (IgG1) were constructed. The expression of the full-length human antibodies on the surface of 293T cell was confirmed by flow cytometry. The libraries showed an expressible combinatory diversity of 7.5x10(10).The expressible antibody library provides a useful platform for screening of renal cell carcinoma-specific antibodies.

To study the effects of UV irradiation on DNA ligation and transformation efficiency of the expression vector into competent bacterial cells.The expression vector was digested with the restriction enzyme SfiI, and the purified target DNA fragments were exposed to UV light at different wavelengths. Ligation and transformation experiments with the exposed fragments were carried out and the colony number and transformation efficiency were assessed.The transformation efficiency of the DNA with a 5-min exposure to 302 nm UV was 60 colonies per nanogram of the DNA, as compared with 20400 for the DNA exposed to 365 nm UV. The time course experiment showed that prolonged DNA exposure to 365 nm UV light was associated with lowered transformation efficiency. DNA exposure for 30 min caused a reduction of the transformation efficiency to lower than 50% compared to that of DNA without UV exposure. But with a 15 min exposure, the DNA maintained a transformation efficiency more than 70%, which was sufficient for most molecular biology experiments.In construction of the expression vector, it is advisable to prevent the target DNA from UV exposure. When UV exposure is essential, we suggest that 365 nm UV be used and the exposure time controlled within 15 min.