Role of Kupffer cells in pathogenesis of sepsis-induced drug metabolizing dysfunction

The present study aimed to determine the role of Kupffer cells (KCs) in cytochrome P450 (CYP) isozyme activity and the expression of its gene during polymicrobial sepsis. For ablation of KCs, rats were pretreated with gadolinium chloride (GdCl(3)) at 48 and 24 h before cecal ligation and puncture (CLP). The depletion of KCs was confirmed by measuring the mRNA level of the KC marker gene CD163. Serum aminotransferase levels and lipid peroxidation showed an increase and hepatic glutathione content showed a decrease at 24 h after CLP. These changes were prevented by GdCl(3) pretreatment. Catalytic activities of CYP1A1, 1A2 and 2E1 showed a significant reduction at 24 h after CLP but were prevented by GdCl(3). A reduction in the levels of CYP2E1 protein and CYP2B1 and CYP2E1 mRNA expression was prevented by GdCl(3). Phosphorylation of CYP1A1/1A2 markedly increased 24 h after CLP, which was prevented by GdCl(3). The increased serum level of high mobility group box 1, hepatic level of Toll-like receptors 2 and 4, and inducible nitric oxide synthase protein expression were prevented by GdCl(3). In addition, elevated serum concentrations of tumor necrosis factor-α and interleukin-6, and increased hepatic mRNA levels of tumor necrosis factor-α and interleukin-6 were decreased by depletion of KCs. Our findings suggest that ablation of KCs protects against hepatic drug-metabolizing dysfunction by modulation of the inflammatory response.     

Fatty acid binding protein 1 is related with development of aspirin-exacerbated respiratory disease

Background

Aspirin-exacerbated respiratory disease (AERD) refers to the development of bronchoconstriction in asthmatics following the ingestion of aspirin. Although alterations in eicosanoid metabolites play a role in AERD, other immune or inflammatory mechanisms may be involved. We aimed to identify proteins that were differentially expressed in nasal polyps between patients with AERD and aspirin-tolerant asthma (ATA).

Methodology/Principal Findings

Two-dimensional electrophoresis was adopted for differential display proteomics. Proteins were identified by liquid chromatography-tandem mass spectrometry (LC-MS). Western blotting and immunohistochemical staining were performed to compare the amount of fatty acid-binding protein 1 (FABP1) in the nasal polyps of patients with AERD and ATA. Fifteen proteins were significantly up- (seven spots) or down-regulated in the nasal polyps of patients with AERD (n = 5) compared to those with ATA (n = 8). LC-MS revealed an increase in seven proteins expression and a decrease in eight proteins expression in patients with AERD compared to those with ATA (P = 0.003–0.045). FABP1-expression based on immunoblotting and immunohistochemical analysis was significantly higher in the nasal polyps of patients with AERD compared to that in patients with ATA. FABP1 was observed in epithelial, eosinophils, macrophages, and the smooth-muscle cells of blood vessels in the polyps.

Conclusions/Significance

Our results indicate that alterations in 15 proteins, including FABP1, may be related to the development of AERD.     

Comparative proteomic analysis for the insoluble fractions of colorectal cancer patients

We used label-free quantitative proteomics with the insoluble fractions from colorectal cancer (CRC) patients to gain further insight into the utility of profiling altered protein expression as a potential biomarker for cancer. The insoluble fractions were prepared from paired tumor/normal biopsies from 13 patients diagnosed with CRC (stages I to IV). Fifty-six proteins identified in data pooled from the 13 cases were differentially expressed between the tumor and adjacent normal tissue. The connections between these proteins are involved in reciprocal networks related to tumorigenesis, cancer incidence based on genetic disorder, and skeletal and muscular disorders. To assess their potential utility as biomarkers, the relative expression levels of the proteins were validated using personal proteomics and a heat map to compare five individual CRC samples with five normal tissue samples. Further validation of a panel of proteins (KRT5, JUP, TUBB, and COL6A1) using western blotting confirmed the differential expression. These proteins gave specific network information for CRC, and yielded a panel of novel markers and potential targets for treatment. It is anticipated that the experimental approach described here will increase our understanding of the membrane environment in CRC, which may provide direction for making diagnoses and prognoses through molecular biomarker targeting.     

In-depth analysis of cysteine oxidation by the RBC proteome: advantage of peroxiredoxin II knockout mice

Peroxiredoxin II (Prdx II, a typical 2-Cys Prdx) has been originally isolated from erythrocytes, and its structure and peroxidase activity have been adequately studied. Mice lacking Prdx II proteins had heinz bodies in their peripheral blood, and morphologically abnormal cells were detected in the dense red blood cell (RBC) fractions, which contained markedly higher levels of reactive oxygen species (ROS). In this study, a labeling experiment with the thiol-modifying reagent biotinylated iodoacetamide (BIAM) in Prdx II-/- mice revealed that a variety of RBC proteins were highly oxidized. To identify oxidation-sensitive proteins in Prdx II-/- mice, we performed RBC comparative proteome analysis in membrane and cytosolic fractions by nano-UPLC-MSE shotgun proteomics. We found oxidation-sensitive 54 proteins from 61 peptides containing cysteine oxidation, and analyzed comparative expression pattern in healthy RBCs of Prdx II+/+ mice, healthy RBCs of Prdx II-/- mice, and abnormal RBCs of Prdx II-/- mice. These proteins belonged to cellular functions related with RBC lifespan maintain, such as cytoskeleton, stress-induced proteins, metabolic enzymes, signal transduction, and transporters. Furthermore, protein networks among identified oxidation-sensitive proteins were analyzed to associate with various diseases. Consequently, we expected that RBC proteome might provide clues to understand redox-imbalanced diseases.     

Neoplastic transformation and tumorigenesis associated with overexpression of IMUP-1 and IMUP-2 genes in cultured NIH/3T3 mouse fibroblasts

Immortalization-upregulated protein 1 (IMUP-1) and immortalization-upregulated protein 2 (IMUP-2) genes have been recently cloned and are known to be involved in SV40-mediated immortalization. IMUP-1 and IMUP-2 genes were strongly expressed in various cancer cell lines and tumors, suggesting the possibility that they might be involved in tumorigenicity. To directly elucidate the functional role of IMUP-1 and IMUP-2 on neoplastic transformation and tumorigenicity, we stably transfected IMUP-1 and IMUP-2 into NIH/3T3 mouse fibroblast cells. Cellular characteristics of the neoplastic transformation were assessed by transformation foci, growth in soft agar, and tumor development in nude mice. We found that IMUP-1 and IMUP-2 overexpressing cells showed altered growth properties, anchorage-independent growth in soft agar and inducing tumor in nude mice. Furthermore, IMUP-1 and IMUP-2 transformants proliferated in reduced serum and shortened cell cycle. These results suggest that ectopic overexpression of IMUP-1 and IMUP-2 may play an important role in acquiring a transformed phenotype, tumorigenicity in vivo, and be related to cellular proliferation.     

Proteomic Analysis of Gingival Tissue and Alveolar Bone during Alveolar Bone Healing

Bone tissue regeneration is orchestrated by the surrounding supporting tissues and involves the build-up of osteogenic cells, which orchestrate remodeling/healing through the expression of numerous mediators and signaling molecules. Periodontal regeneration models have proven useful for studying the interaction and communication between alveolar bone and supporting soft tissue. We applied a quantitative proteomic approach to analyze and compare proteins with altered expression in gingival soft tissue and alveolar bone following tooth extraction. For target identification and validation, hard and soft tissue were extracted from mini-pigs at the indicated times after tooth extraction. From triplicate experiments, 56 proteins in soft tissue and 27 proteins in alveolar bone were found to be differentially expressed before and after tooth extraction. The expression of 21 of those proteins was altered in both soft tissue and bone. Comparison of the activated networks in soft tissue and alveolar bone highlighted their distinct responsibilities in bone and tissue healing. Moreover, we found that there is crosstalk between identified proteins in soft tissue and alveolar bone with respect to cellular assembly, organization, and communication. Among these proteins, we examined in detail the expression patterns and associated networks of ATP5B and fibronectin 1. ATP5B is involved in nucleic acid metabolism, small molecule biochemistry, and neurological disease, and fibronectin 1 is involved in cellular assembly, organization, and maintenance. Collectively, our findings indicate that bone regeneration is accompanied by a profound interaction among networks regulating cellular resources, and they provide novel insight into the molecular mechanisms involved in the healing of periodontal tissue after tooth extraction.Healthy dental gingival tissue and the alveolar bone that surrounds the teeth are essential for the proper function of teeth, as well as for a good appearance and good general health. Socket healing after tooth extraction is a useful experimental model for investigating the communication between gingival tissue and alveolar bone after tooth extraction. Preservation of the alveolar socket after tooth extraction requires the formation of a biological connection between the living and osseous tissue, which has to be created during the healing process. The success of such dental remodeling is dependent on the establishment of a soft tissue barrier that is able to shelter the underlying osseous structures and the osseo-integration of the soft tissue surrounding the alveolar bone. Understanding the processes governing soft and hard tissue healing and maintenance around the alveolar socket is paramount for oral health.Several studies have reported significant structural changes and bone reabsorption in fresh sockets following tooth extraction, with important dimensional changes in the surrounding alveolar bone (1–3). A reduction of alveolar bone may present problems after tooth extraction, especially in aged individuals in whom bone volume is important for both physiological and medical reasons. Although it has been shown that reduction defects in alveolar bone can be completely repaired using surgical techniques such as guided bone regeneration (4, 5), bone autograft, bone allograft, and xenograft (6, 7), these techniques are not broadly applicable (8). However, the introduction of biomimetic agents such as enamel matrix derivatives (9), platelet-rich plasma (10), platelet-derived growth factor (11, 12), and bone morphogenic proteins (BMPs)¹ (9) promises potentially better outcomes with bone regeneration treatments, although their efficacy remains controversial.The proteins present in bone are essential for all of the life processes ongoing in bone, and they are the most important final products of the homeostatic signaling pathways. Profiling those proteins is vital for a thorough understanding of bone biology. To date, proteome research on bone has been focused mainly on in vitro analysis of bone-forming cells (osteoblasts and osteoclasts) to determine which proteins are expressed under a given set of experimental conditions (13–16). Although important, such studies cannot identify the actual protein profile in oral alveolar bone. Recently, the extraction of proteins directly from skull bone for proteome analysis was reported (17, 18). The extracted proteins were first separated using two-dimensional gel electrophoresis, after which spots of interest were excised and the proteins were identified via mass spectrometry (MS). However, using two-dimensional gel electrophoresis to analyze extreme proteins (e.g. extremely basic or acidic, extremely small or large, extremely hydrophobic) is challenging. Shotgun proteomics, which is a method of high-throughput proteome analysis (19–21), avoids the intrinsic limitations of two-dimensional gel electrophoresis. Despite an interesting need for large-scale characterization of the bone proteome, one study has been reported to apply shotgun proteomics for proteome analysis of rat femur bone (22). However, they identified only 133 proteins, because they analyzed bone proteins using a one-step method without a demineralization stage. The other report showed only that bone proteins extracted from the skull bone of an adult beagle are carried using a demineralization step (23). There are no reports regarding the interaction between alveolar bone and soft tissue yet.The efficient extraction of bone proteins is a critical issue for proteome analysis (24). Because bone is largely mineralized, and therefore nearly solid, classical protein extraction methods used for soft tissues and cells may not be appropriate for bone. It is therefore necessary to develop methods to efficiently extract protein from bone. In earlier bone proteome analyses (17, 18, 22), the bones were first ground to powder, after which the proteins were extracted by means of incubating the powder in lysis buffer. However, mechanically breaking bones down into powder is laborious, especially for large animal bones. More important, large amounts of collagen and proteoglycans also are extracted, and this can impair the detection of low-abundance proteins and strongly affect isoelectric focusing (25). For the present study, we adopted an alternative method of demineralizing bone tissue and then investigated the efficiency of protein extraction from the demineralized bone tissue. This method was based on a recently reported sequential protein extraction protocol that was used to extract proteins from skull for comprehensive analysis of its proteome. Two-dimensional high-performance liquid chromatography–tandem mass spectrometry (LC-MS/MS) was then applied to analyze the protein extracts, enabling the identification of 2479 proteins (23). We employed a similar method to extract and identify proteins in tooth alveolar bone.Given that a large number of proteins are likely involved in the healing of bone, as well as of soft tissues, another goal of the present study was to examine protein expression and putative signaling during bone healing after tooth extraction. Here, we used nano-UPLC-MS^E-based label-free quantitative proteomics to analyze alveolar bone and the adjacent soft tissue. The environment surrounding healing bone would be expected to affect the specific signaling networks involved in bone regeneration. We suggest that determining the protein networks in alveolar bone and gingival tissue will enable improvement of the soft tissue interface, aspects of the hard tissue, and dental appearance during and after therapy.     

Low Left Atrial Compliance Contributes to the Clinical Recurrence of Atrial Fibrillation after Catheter Ablation in Patients with Structurally and Functionally Normal Heart

Stiff left atrial (LA) syndrome was initially reported in post-cardiac surgery patients and known to be associated with low LA compliance. We investigated the physiological and clinical implications of LA compliance by estimating LA pulse pressure (LApp) among patients with atrial fibrillation (AF) and structurally and functionally normal heart. Among 1038 consecutive patients with LA pressure measurements before AF ablation, we included 334 patients with structurally and functionally normal heart (81.7% male, 54.1±10.6 years, 77.0% paroxysmal AF) after excluding those with hypertension, diabetes, and previous ablation or cardiac surgery. We measured LApp (peak-nadir LA pressure) at the beginning of the ablation procedure and compared the values with clinical parameters and the AF recurrence rate.AF patients with normal heart were younger and more frequently male and had paroxysmal AF, a lower body mass index, and a lower LApp compared to others (all p<0.05).Based on the median value, the low LA compliance group (LApp≥13mmHg) had a smaller LA volume index and lower LA voltage (all p<0.05) compared to the high LA compliance group. During a mean follow-up of 16.7±11.8 months, low LA compliance was independently associated with two fold-higher risk of clinical AF recurrence (HR:2.202; 95%CI:1.077–4.503; p = 0.031).Low LA compliance, as determined by an elevated LApp, was associated with a smaller LA volume index and lower LA voltage and independently associated with higher clinical recurrence after catheter ablation in AF patients with structurally and functionally normal heart.     

cDNA cloning and expression pattern of cinnamate-4-hydroxylase in the Korean black raspberry

Cinnamate-4-hydroxylase (C4H) is a key enzyme in the phenylpropanoid pathway, which is responsible for synthesizing a variety of secondary metabolites that participate in development and adaptation. In this study, we isolated a full-length cDNA of the C4H gene from the Korean black raspberry (Rubus sp.) and found that this gene existed as a single gene. By comparing the deduced amino acid sequence of Rubus sp. C4H with other sequences reported previously we determined that this sequence was highly conserved among widely divergent plant species. In addition, quantitative real time PCR studies indicated that the C4H gene had a differential expression pattern during fruit development, where gene expression was first detected in green fruit and was then remarkably reduced in yellow fruit, followed by an increase in red and black fruit. To investigate the two peaks in expression observed during fruit development and ripening, we measured the flavonoid content. The content of the major flavanol of Korean black raspberry fruits was determined to be highest at the beginning of fruit development, followed by a gradually decrease according to the developmental stages. In contrast, the content of anthocyanins during the progress of ripening was dramatically increased. Our results suggest that the C4H gene in Korean black raspberry plays a role during color development at the late stages of fruit ripening, whereas the expression of C4H gene during the early stages may be related to the accumulation of flavanols.