Hedgehog signaling induces osteosarcoma development through Yap1 and H19 overexpression

Osteosarcoma is one of the most common bone tumors. However, the genetic basis for its pathogenesis remains elusive. Here, we investigated the roles of Hedgehog (Hh) signaling in osteosarcoma development. Genetically-engineered mice with ubiquitous upregulated Hh signaling specifically in mature osteoblasts develop focal bone overgrowth, which greatly resembles the early stage of osteosarcoma. However, these mice die within three months, which prohibits further analysis of tumor progression. We therefore generated a mouse model with partial upregulated Hh signaling in mature osteoblasts and crossed it into a p53 heterozygous background to potentiate tumor development. We found that these mutant mice developed malignant osteosarcoma with high penetrance. Isolated primary tumor cells were mainly osteoblastic and highly proliferative with many characteristics of human osteosarcomas. Allograft transplantation into immunocompromised mice displayed high tumorigenic potential. More importantly, both human and mouse tumor tissues express high level of yes-associated protein 1 (Yap1), a potent oncogene that is amplified in various cancers. We show that inhibition of Hh signaling reduces Yap1 expression and knockdown of Yap1 significantly inhibits tumor progression. Moreover, long non-coding RNA H19 is aberrantly expressed and induced by upregulated Hh signaling and Yap1 overexpression. Our results demonstrate that aberrant Hh signaling in mature osteoblasts is responsible for the pathogenesis of osteoblastic osteosarcoma through Yap1 and H19 overexpression.

[Analysis of clinical features of 29 patients with 2019 novel coronavirus pneumonia]

Objective: To analyze the clinical characteristics of 2019 novel coronavirus (2019-nCoV) pneumonia and to investigate the correlation between serum inflammatory cytokines and severity of the disease. Methods: 29 patients with 2019-ncov admitted to the isolation ward of Tongji hospital affiliated to Tongji medical college of Huazhong University of Science and Technology in January 2020 were selected as the study subjects. Clinical data were collected and the general information, clinical symptoms, blood test and CT imaging characteristics were analyzed. According to the relevant diagnostic criteria, the patients were divided into three groups: mild (15 cases), severe (9 cases) and critical (5 cases). The expression levels of inflammatory cytokines and other markers in the serum of each group were detected, and the changes of these indicators of the three groups were compared and analyzed, as well as their relationship with the clinical classification of the disease. Results: (1) The main symptoms of 2019-nCoV pneumonia was fever (28/29) with or without respiratory and other systemic symptoms. Two patients died with underlying disease and co-bacterial infection, respectively. (2) The blood test of the patients showed normal or decreased white blood cell count (23/29), decreased lymphocyte count (20/29), increased hypersensitive C reactive protein (hs-CRP) (27/29), and normal procalcitonin. In most patients,serum lactate dehydrogenase (LDH) was significantly increased (20/29), while albumin was decreased(15/29). Alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (Tbil), serum creatinine (Scr) and other items showed no significant changes. (3) CT findings of typical cases were single or multiple patchy ground glass shadows accompanied by septal thickening. When the disease progresses, the lesion increases and the scope expands, and the ground glass shadow coexists with the solid shadow or the stripe shadow. (4) There were statistically significant differences in the expression levels of interleukin-2 receptor (IL-2R) and IL-6 in the serum of the three groups (P<0.05), among which the critical group was higher than the severe group and the severe group was higher than the mildgroup. However, there were no statistically significant differences in serum levels of tumor necrosis factor-alpha (TNF-α), IL-1, IL-8, IL-10, hs-CRP, lymphocyte count and LDH among the three groups (P>0.05). Conclusion: The clinical characteristics of 2019-nCoV pneumonia are similar to those of common viral pneumonia. High resolution CT is of great value in the differential diagnosis of this disease. The increased expression of IL-2R and IL-6 in serum is expected to predict the severity of the 2019-nCoV pneumonia and the prognosis of patients.

Materials design of ceramic-based layer structures for crowns

Radial cracking has been identified as the primary mode of failure in all-ceramic crowns. This study investigates the hypothesis that critical loads for radial cracking in crown-like layers vary explicitly as the square of ceramic layer thickness. Experimental data from tests with spherical indenters on model flat laminates of selected dental ceramics bonded to clear polycarbonate bases (simulating crown/dentin structures) are presented. Damage initiation events are video-recorded in situ during applied loading, and critical loads are measured. The results demonstrate an increase in the resistance to radial cracking for zirconia relative to alumina and for alumina relative to porcelain. The study provides simple a priori predictions of failure in prospective ceramic/substrate bilayers and ranks ceramic materials for best clinical performance.

Xanthene-bridged cofacial bisporphyrins

The synthesis and characterization of cofacial bisporphyrins juxtaposed by xanthene-bridged pillars are presented. The one-pot preparation of the xanthene dialdehyde avoids the lengthy bridge synthesis accompanying other cofacial porphyrin systems, thus allowing for the facile preparation of homobimetallic zinc (10), copper (11), and nickel (12) complexes. The cofacial orientation of the two porphyrin macrocycles was confirmed by X-ray crystallography. Structural data are provided for bisporphyrins 10-12: 10 (C79H82N8OZn2), triclinic, space group P1, a = 11.2671(2) A, b = 14.9809(2) A, c = 20.4852(2) A, alpha = 101.6680(10) degrees, beta = 100.8890(10) degrees, gamma = 101.8060(10) degrees, Z = 2; 11 (C79H82N8OCu2), triclinic, space group P1, a = 11.21410(10) A, b = 14.9539(5) A, c = 20.6915(7) A, alpha = 101.810(2) degrees, beta = 101.044(2) degrees, gamma = 101.722(2) degrees, Z = 2; 12 (C79H82N8ONi2), monoclinic, space group C2/c, a = 24.1671(4) A, b = 10.669 A, c = 50.5080(9) A, beta = 99.553(2) degrees, Z = 8. Exciton interactions between the porphyrin rings are apparent in electronic spectra, consistent with the cofacial superstructure. The combination of structural and spectroscopic data provides a basis for the design of additional metal derivatives for the activation of dioxygen and other small molecules.

Reachability analysis of real-time systems using time Petri nets

Time Petri nets (TPNs) are a popular Petri net model for specification and verification of real-time systems. A fundamental and most widely applied method for analyzing Petri nets is reachability analysis. The existing technique for reachability analysis of TPNs, however, is not suitable for timing property verification because one cannot derive end-to-end delay in task execution, an important issue for time-critical systems, from the reachability tree constructed using the technique. In this paper, we present a new reachability based analysis technique for TPNs for timing property analysis and verification that effectively addresses the problem. Our technique is based on a concept called clock-stamped state class (CS-class). With the reachability tree generated based on CS-classes, we can directly compute the end-to-end time delay in task execution. Moreover, a CS-class can be uniquely mapped to a traditional state class based on which the conventional reachability tree is constructed. Therefore, our CS-class-based analysis technique is more general than the existing technique. We show how to apply this technique to timing property verification of the TPN model of a command and control (C2) system.

Mechanism of the tumor necrosis factor alpha-mediated induction of endothelial tissue factor

This study examines the regulation of the human tissue factor (TF) promotor in vitro and in vivo. Transient transfections were performed in bovine aortic endothelial cells to investigate the role of two fundamentally different AP-1 sites and a closely located NF-kappa B site in the human TF promoter. The NF-kappa B site is functionally active, since overexpression of NF-kappa B(p65) resulted in induction of TF mRNA and activity. Promoter analysis showed that NF-kappa B induction was dependent on the integrity of the region from base pair -188 to -181. Over-expression of Jun/Fos resulted in TF induction of transcription and protein/activity. Functional studies revealed that the proximal AP-1 site, but not the distal, was inducible by Jun/Fos heterodimers. The distal AP-1 site, which has a G-->A switch at position 4, was inductible by Jun homodimers. Electrophoretic mobility shift assays, using extracts of tumor necrosis factor alpha (TNF alpha)-stimulated bovine aortic endothelial cells, demonstrated TNF alpha-inducible binding to the proximal AP-1 site, comprising JunD/Fos heterodimers. At the distal AP-1 site, only minor induction of binding activity, characterized as proteins of the Jun and ATF family, was observed. Consistently, this site only marginally participates in TNF alpha induction. Functional studies with TF promotor plasmids confirmed that deletion of the proximal AP-1 or the NF-kappa B site decreased TNF alpha-mediated TF induction to a higher extend than loss of the distal AP-1 site. However, integrity of both AP-1 sites and the NF-kappa B site was required for optimal TNF alpha stimulation. The relevance of these in vitro data was confirmed in vivo in a mouse tumor model. Expression plasmids for a dominant negative Jun mutant or I-kappa B were packaged in liposomes. When either mutated Jun or I-kappa B were injected intravenously 48 h before TNF alpha, a reduction in TNF alpha-mediated TF expression in the tumor endothelial cells was observed. Simultaneously, fibrin/fibrinogen deposition decreased and free blood flow could be restored. Thus, TNF alpha-induced up-regulation of endothelial cell TF depends on a concerted action of members of the bZIP and NF-kappa B family.

Preoperative mobilization of circulating dendritic cells by Flt3 ligand administration to patients with metastatic colon cancer

PURPOSE

To evaluate preoperative dendritic cell (DC) mobilization and tumor infiltration after administration of Flt3 ligand (Flt3L) to patients with metastatic colon cancer.

PATIENTS AND METHODS

Twelve patients with colon cancer metastatic to the liver or lung received Flt3L (20 microg/kg/d subcutaneously for 14 days for one to three cycles at monthly intervals) before attempted metastasectomy. The number and phenotype of DCs mobilized into peripheral-blood mononuclear cells (PBMCs) were evaluated by flow cytometry. After surgical resection, metastatic tumor tissue was evaluated for DC infiltration. In vivo immune responses to recall antigens were measured.

RESULTS

After Flt3L administration, on average, the total number of leukocytes in the peripheral blood increased from 5.9 +/- 1.0 x 10(3)/mm(3) to 11.2 +/- 3.8 x 10(3)/mm(3) (mean +/- SD, P: =. 0001). The percentage of CD11c(+)CD14(-) DCs in PBMCs increased from 2.4% +/- 1.8% to 8.8% +/- 4.7% (P: =.004). Delayed-type hypersensitivity (DTH) responses to recall antigens (CANDIDA:, mumps, and tetanus) showed marginally significant increases in reactivity after Flt3L administration (P: =.06, P: =.03, and P: =.08, respectively). An increase in the number of DCs was observed at the periphery of the tumors of patients who received Flt3L compared with those of patients who had not.

CONCLUSION

Flt3L is capable of mobilizing DCs into the peripheral blood of patients with metastatic colon cancer and may be associated with increases in DC infiltration in the peritumoral regions. Flt3L mobilization is associated with a trend toward increased DTH responses to recall antigens in vivo. The use of Flt3L to increase circulating DCs for cancer immunotherapy should be considered.

Chip-based capillary electrophoresis/mass spectrometry determination of carnitines in human urine

A chip-based capillary electrophoresis/mass spectrometry (CE/MS) system is described for the CE separation and on-line electrospray detection of carnitine and selected acylcarnitines from mixtures of analytical standards as well as extracts of fortified human urine. Chip-based CE/MS experiments in two different laboratories were carried out using a triple-quadrupole mass spectrometer and a quadrupole time-of-flight (QTOF) mass spectrometer, respectively. The glass chips used with both systems were comparably equipped with a microfabricated capillary electrophoresis (CE) channel but with different electrosprayers. The quadrupole chip-based CE/MS experiments employed a miniature coupled microsprayer, which allowed coupling of the microelectrospray process via a micro liquid junction at the exit of the CE capillary channel. Selected ion monitoring (SIM) CE/MS experiments were employed for all of the quadrupole CE/MS work. The QTOF CE/MS full-scan single MS and MS/MS experiments were carried out in another laboratory using accurate mass measurement TOF mass spectrometry techniques. The electrospray process that was employed with the QTOF system differed in that an inserted nanoelectrospray capillary needle was carefully affixed into a flat-bottomed hole that was aligned with the CE channel exit orifice. SIM CE/MS using the described quadrupole system provided acceptable ion current electropherograms from fmole levels from analytical standard solutions of carnitine and acylcarnitines that were manually injected (loaded) onto the chip. In addition, the corresponding electropherograms for human urine fortified with the target carnitine and acylcarnitines at a 10-20 microg/mL (35-124 microM) level were obtained via SIM CE/MS techniques. The measured CE separation efficiency for the SIM CE/MS electropherograms was determined to be 2860 plates (peak width at half-height method or N = 5.54(T/WO.5(2)), and carnitine and three acylcarnitines were separated in less than 48 s. In contrast, using quadrupole-TOF technologies, the same samples could be diluted by a factor of 2-4 to obtain a comparable detector response for the target compounds. In the full-scan, single mass analyzer mode (m/z 150-500), the CE separation efficiency was measured to be 2600 plates, but mass measurement accuracy was less than 5.0 ppm for the quaternary cations. In the CE/MS/MS mode, full-scan collision-induced dissociation (CID) mass spectra were obtained with a mass accuracy of < or =10 ppm for the higher mass ions and < or =27 ppm for the lower mass product ions. These results demonstrate the feasibility for on-chip CE separation and electrospray mass spectrometric detection for these important compounds in synthetic mixtures, as well as in human urine extracts.

Grb10, a positive, stimulatory signaling adapter in platelet-derived growth factor BB-, insulin-like growth factor I-, and insulin-mediated mitogenesis

Grb10 has been described as a cellular partner of several receptor tyrosine kinases, including the insulin receptor (IR) and the insulin-like growth factor I (IGF-I) receptor (IGF-IR). Its cellular role is still unclear and a positive as well as an inhibitory role in mitogenesis depending on the cell context has been implicated. We have tested other mitogenic receptor tyrosine kinases as putative Grb10 partners and have identified the activated forms of platelet-derived growth factor (PDGF) receptor beta (PDGFRbeta), hepatocyte growth factor receptor (Met), and fibroblast growth factor receptor as candidates. We have mapped Y771 as a PDFGRbeta site that is involved in the association with Grb10 via its SH2 domain. We have further investigated the putative role of Grb10 in mitogenesis with four independent experimental strategies and found that all consistently suggested a role as a positive, stimulatory signaling adaptor in normal fibroblasts. (i) Complete Grb10 expression from cDNA with an ecdysone-regulated transient expression system stimulated PDGF-BB-, IGF-I, and insulin- but not epidermal growth factor (EGF)-induced DNA synthesis in an ecdysone dose-responsive fashion. (ii) Microinjection of the (dominant-negative) Grb10 SH2 domain interfered with PDGF-BB- and insulin-induced DNA synthesis. (iii) Alternative experiments were based on cell-permeable fusion peptides with the Drosophila antennapedia homeodomain which effectively traverse the plasma membrane of cultured cells. A cell-permeable Grb10 SH2 domain similarly interfered with PDGF-BB-, IGF-I-, and insulin-induced DNA synthesis. In contrast, a cell-permeable Grb10 Pro-rich putative SH3 domain binding region interfered with IGF-I- and insulin- but not with PDGF-BB- or EGF-induced DNA synthesis. (iv) Transient overexpression of complete Grb10 increased whereas cell-permeable Grb10 SH2 domain fusion peptides substantially decreased the cell proliferation rate (as measured by cell numbers) in normal fibroblasts. These experimental strategies independently suggest that Grb10 functions as a positive, stimulatory, mitogenic signaling adapter in PDGF-BB, IGF-I, and insulin action. This function appears to involve the Grb10 SH2 domain, a novel sequence termed BPS, and the Pro-rich putative SH3 domain binding region in IGF-I- and insulin-mediated mitogenesis. In contrast, PDGF-BB-mediated mitogenesis appears to depend on the SH2 but not on the Pro-rich region and may involve other, unidentified Grb10 domains. Distinct protein domains may help to define specific Grb10 functions in different signaling pathways.

Cubic membrane structure in amoeba (Chaos carolinensis) mitochondria determined by electron microscopic tomography

Cubic membranes occur in a variety of membrane-bound organelles in many cell types. By transmission electron microscopy (TEM) these membrane systems appear to consist of highly curved periodic surfaces that fit mathematical models analogous to those used to describe lipidic cubic phases. For the first time, a naturally occurring cubic membrane system has been reconstructed in three dimensions by electron microscopic tomography, and its periodicity directly characterized. Double-tilt tomographic reconstruction of mitochondria in the amoeba, Chaos carolinensis, confirms that their cristae (inner membrane infoldings) have the cubic structure suggested by modeling studies based on thin-section TEM images. Analysis of the membrane surfaces in the reconstruction reveals the connectivity of the internal compartments within the mitochondria. In the cubic regions, the matrix is highly condensed and confined to a continuous, small space between adjacent cristal membranes. The cristae form large, undulating cisternae that communicate with the peripheral (inner membrane) compartment through narrow tubular segments as seen in other types of mitochondria. The cubic periodicity of these mitochondrial membranes provides an ideal specimen for measuring geometrical distortions in biological electron tomography. It may also prove to be a useful model system for studies of the correlation of cristae-matrix organization with mitochondrial activity.

Identification and characterization of a gene cluster mediating enteroaggregative Escherichia coli aggregative adherence fimbria I biogenesis

The aggregative pattern of adherence (AA) exhibited by enteroaggregative Escherichia coli upon HEp-2 cells is a plasmid-associated property which correlates with aggregative adherence fimbria I (AAF/I) expression and human erythrocyte hemagglutination. By using cloning and mutagenesis strategies, two noncontiguous plasmid segments (designated regions 1 and 2) required for AA expression have previously been identified in enteroaggregative E. coli 17-2. TnphoA mutagenesis was performed on clones containing region 1, and 16 TnphoA mutants which were negative for the AA phenotype were analyzed. The TnphoA insertion site for each mutant was determined by junctional DNA sequencing. All 16 mutations occurred within a 4.6-kb span in region 1. Nucleotide sequence analysis of the region revealed four contiguous open reading frames, designated aggDCBA, in the same span. AA-negative TnphoA insertions into all open reading frames except aggB were obtained. On the basis of mutational analysis and protein homology data, it is inferred that aggA, aggC, and aggD are involved in biogenesis of AAF/I, encoding a major fimbrial subunit, outer membrane usher, and periplasmic fimbrial chaperone, respectively. By immunogold electron microscopy, polyclonal antiserum raised against the aggA gene product decorated AAF/I fimbriae, affirming that AggA encodes an AAF/I subunit.

Uptake of a neurotoxin-candidate, (R)-1,2-dimethyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline into human dopaminergic neuroblastoma SH-SY5Y cells by dopamine transport system

Uptake of catechol isoquinolines to dopamine cells was studied using human dopaminergic neuroblastoma SH-SY5Y cells. Only (R)-1,2-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline [(R)-1,2-DiMeDHTIQ] was transported by dopamine uptake system, while (S)-1,2-DiMeDHTIQ, (R)- and (S)-1-methyl-6,7-dihydroxy-tetrahydroisoquinoline, and 1,2-dimethyl-6,7-dihydroxyisoquinolinum ion were not. Kinetical study showed that the uptake of (R)-1,2-DiMeDHTIQ followed the Michaelis-Menten equation, and the values of the Michaelis constant and the maximal velocity were obtained to be 102.6 +/- 36.9 microM and 66.0 +/- 2.8 pmol/min/mg protein. Dopamine was found to inhibit (R)-1,2-DiMeDHTIQ uptake competitively. These results suggest that the selective uptake by dopamine transporter may account for the specific neurotoxicity of (R)-1,2-DiMeDHTIQ to dopamine neurons.

Repair of critical-sized bone defects with anti-miR-31-expressing bone marrow stromal stem cells and poly(glycerol sebacate) scaffolds

The repair of critical-sized defects (CSDs) is a significant challenge in bone tissue engineering. Combining the use of progenitor cells with gene therapy represents a promising approach for bone regeneration. MicroRNAs play important roles in most gene regulatory networks, regulate the endogenous expression of multiple growth factors and simultaneously modulate stem cell differentiation. Our previous study showed that knocking down miR-31 promotes the osteogenesis of bone marrow stromal stem cells (BMSCs). To investigate the therapeutic potential of cells engineered to express anti-miR-31 for CSD repair, lentiviral vectors encoding negative control, miR-31 precursor and anti-sense sequences were constructed and transduced into osteo-inductive BMSCs. The expression of osteogenic-specific genes, alkaline phosphatase activity and Alizarin Red S staining were investigated to evaluate the effects of miR-31 on the cell fate of BMSCs over a 3-week period. In addition, miR-31-modified BMSCs seeded on poly(glycerol sebacate) (PGS) scaffolds were used to repair 8 mm critical-sized calvarial defects in rats. The results showed that miR-31 suppression significantly increased the expression of osteogenic-specific genes in vitro at the mRNA and protein levels, and that robust new bone formation with high local bone mineral density was observed in the anti-miR groups in vivo. Moreover, the PGS scaffolds carrying anti-miR-31-expressing BMSCs exhibited good biocompatibility and a high regeneration rate (~60%) within in vivo bone defects. Our results suggest that miR-31 gene delivery affects the potential of BMSCs for osteogenic differentiation and bone regeneration and that PGS is a potential substrate for genetically modified, tissue-engineered bone in the repair of large bone defects.

Thrombomodulin modulates growth of tumor cells independent of its anticoagulant activity

Thrombomodulin (TM), recognized as an essential vessel wall cofactor of the antithrombotic mechanism, is also expressed by a wide range of tumor cells. Tumor cell lines subcloned from four patients with malignant melanoma displayed a negative correlation between TM expression and cell proliferation in vitro and in vivo. Overexpression of wild-type TM decreased cell proliferation in vitro and tumor growth in vivo. TM mutants with altered protein C activation capacity lead to a similar effect. In contrast, transfection of melanoma cells with mutant TM constructs, in which a portion of the cytoplasmic or lectin domain was deleted, abrogated the antiproliferative effect associated with overexpression of wild-type TM. Experiments performed with either peptide agonists/antagonists of the thrombin receptor, with hirudin, or with inhibitors of thrombin-TM interaction did not alter the growth inhibitory effect of TM overexpression. These data suggest that TM exerts an effect on cell proliferation independent of thrombin and the thrombin receptor, possibly related to the binding of novel ligands to determinants in the lectin domain which might trigger signal transduction pathways dependent on the cytoplasmic domain.

Helminth antigen-based strategy to ameliorate inflammation in an experimental model of colitis

Inflammatory bowel disease (IBD) is the most common and serious chronic inflammatory condition of the gut. Among the distinct T helper (Th) cell subsets, a Th1 type response is associated predominantly with Crohn's disease (CD) while helminth infections generate a strong Th2 type response. IBD is most prevalent in developed countries but rare in countries where infections with helminths are common. Thus, it has been hypothesized that infection with helminth infection influence the development of CD and recent clinical and experimental studies suggest strongly a beneficial role of helminth infection in IBD. In the present study we examined the effects of rectal submucosal administration of helminth antigens on subsequent experimental colitis. Mice were treated with Trichinella spiralis antigens prior to the induction of dinitrobenzenesulphonic acid (DNBS)-induced colitis and were killed 3 days post-DNBS to assess colonic damage macroscopically, histologically and by myeloperoxidase (MPO) activity, inducible nitric oxide synthase (iNOS) and cytokine levels. Previous treatment with T. spiralis antigens reduced the severity of colitis significantly, as assessed macroscopically and histologically, and reduced the mortality rate. This benefit was correlated with a down-regulation of MPO activity, interleukin (IL)-1beta production and iNOS expression and an up-regulation of IL-13 and transforming growth factor-beta production in colon. These results clearly show a beneficial role of local treatment with helminth antigens for experimental colitis and prompt consideration of helminth antigen-based therapy for IBD instead of infection with live parasites.

Identification and characterization of the novel Col10a1 regulatory mechanism during chondrocyte hypertrophic differentiation

The majority of human skeleton develops through the endochondral pathway, in which cartilage-forming chondrocytes proliferate and enlarge into hypertrophic chondrocytes that eventually undergo apoptosis and are replaced by bone. Although at a terminal differentiation stage, hypertrophic chondrocytes have been implicated as the principal engine of bone growth. Abnormal chondrocyte hypertrophy has been seen in many skeletal dysplasia and osteoarthritis. Meanwhile, as a specific marker of hypertrophic chondrocytes, the type X collagen gene (COL10A1) is also critical for endochondral bone formation, as mutation and altered COL10A1 expression are often accompanied by abnormal chondrocyte hypertrophy in many skeletal diseases. However, how the type X collagen gene is regulated during chondrocyte hypertrophy has not been fully elucidated. We have recently demonstrated that Runx2 interaction with a 150-bp mouse Col10a1 cis-enhancer is required but not sufficient for its hypertrophic chondrocyte-specific reporter expression in transgenic mice, suggesting requirement of additional Col10a1 regulators. In this study, we report in silico sequence analysis of this 150-bp enhancer and identification of its multiple binding factors, including AP1, MEF2, NFAT, Runx1 and TBX5. Using this enhancer as bait, we performed yeast one-hybrid assay and identified multiple candidate Col10a1-interacting genes, including cyclooxygenase 1 (Cox-1) and Cox-2. We have also performed mass spectrometry analysis and detected EF1-alpha, Fus, GdF7 and Runx3 as components of the specific complex formed by the cis-enhancer and nuclear extracts from hypertrophic MCT (mouse chondrocytes immortalized with large T antigen) cells that express Col10a1 abundantly. Notably, some of the candidate genes are differentially expressed in hypertrophic MCT cells and have been associated with chondrocyte hypertrophy and Runx2, an indispensible Col10a1 regulator. Intriguingly, we detected high-level Cox-2 expression in hypertrophic MCT cells. Electrophoretic mobility shift assay and chromatin immunoprecipitation assays confirmed the interaction between Cox-2 and Col10a1 cis-enhancer, supporting its role as a candidate Col10a1 regulator. Together, our data support a Cox-2-containing, Runx2-centered Col10a1 regulatory mechanism, during chondrocyte hypertrophic differentiation.

Critical role for signal transducer and activator of transcription factor 6 in mediating intestinal muscle hypercontractility and worm expulsion in Trichinella spiralis-infected mice

Intestinal nematode infections in rats or mice are accompanied by intestinal muscle hyper contractility that may contribute to parasite expulsion from the gut. Previous studies demonstrated that both the expulsion of nematode parasites and the associated muscle hyper contractility are dependent on CD4(+) T helper cells. Nevertheless, the precise immunological mechanism underlying changes in intestinal muscle function remains to be determined. In this study, we investigated the role of interleukin 4 (IL-4) and signal transducer and activator of transcription factor 6 (STAT6) in the development of intestinal muscle hypercontractility and worm expulsion by infecting IL-4 and STAT6-deficient mice with Trichinella spiralis. Worm expulsion was almost normal in IL-4-deficient mice but substantially delayed in STAT6-deficient mice. Consistent with delayed worm expulsion, we also observed a marked attenuation of carbachol-induced muscle contraction in STAT6-deficient mice but only a moderate decrease in muscle hypercontractility in IL-4-deficient mice. In addition, we also observed severe impairment of T helper type 2 cytokine responses and intestinal mucosal mastocytosis in STAT6-deficient mice, although some degree of intestinal tissue eosinophilia was evident in these animals. These results are consistent with the hypothesis that STAT6-dependent changes in intestinal muscle function contribute to host protection in nematode infection.

Chip-based quantitative capillary electrophoresis/mass spectrometry determination of drugs in human plasma

A chip-based capillary electrophoresis/mass spectrometry (CE/MS) system is described for the on-chip separation and coupled electrospray detection of selected small drug molecule compounds. These studies include the quantitative determination of carnitine and acetylcarnitine in analytical standard solutions as well as imipramine and desipramine in fortified human plasma samples. A clinical human plasma sample was also analyzed following the normal administration of desipramine to a volunteer, and the parent drug was determined using the described chipbased CE/MS technique. In each instance, stable isotope-incorporated internal standards were used. The chip-based CE system was microfabricated from glass and coupled to a micro ion spray device constructed in-house. The atmospheric pressure ionization system employed in this work was a PE Sciex API III tandem triple quadrupole system operated in the selected ion monitoring (SIM) mode. The results from the work reported here demonstrate the feasibility for carrying out rapid (30 s) chipbased quantitative CE/MS determinations of samples containing small-molecule compounds. Using SIM CE/ MS techniques, the described API III quadrupole system provided acceptable ion current electropherograms from subpicomole levels of the targeted compounds loaded onto the chip. The corresponding electropherograms for the standard solution of carnitines at the 1-500 microg/mL level were obtained via SIM CE/MS techniques (R2 > 0.99). In addition, analyses of fortified samples of imipramine desipramine were measured relative to their corresponding d3 internal standards to obtain calibration curves ranging from 5 to 500 microg/mL in human plasma (R2 > 0.99). The intra-assay precision ranged from 4.1 to 7.3% RSD. The intra-assay accuracy ranged from 94.0 to 104%. These results demonstrate the feasibility for on-chip CE separation and electrospray mass spectrometric determination in applications for bioanalytical measurements for these important compounds in synthetic mixtures and human plasma extracts.

Role of immunologic factors and cyclooxygenase 2 in persistent postinfective enteric muscle dysfunction in mice

BACKGROUND & AIMS

Chronic abdominal symptoms develop in some patients after acute enteric infection. This study examined mechanisms underlying smooth muscle hypercontractility that persists after acute infection in mice.

METHODS

Euthymic and athymic National Institutes of Health (NIH) Swiss mice were infected with Trichinella spiralis and studied 4 weeks postinfection (PI). Isometric tension was assessed in longitudinal muscle. Cytokine and cyclooxygenase (COX)-2 messenger RNA was determined in the muscularis externa by reverse-transcription polymerase chain reaction. COX-2 protein was identified by immunohistochemistry and prostaglandin E(2) was measured by enzymatic immunoassay. Studies were performed in euthymic and athymic NIH Swiss mice 28 days PI and in the presence or absence of treatment with corticosteroid or COX inhibitors.

RESULTS

Muscle hypercontractility was evident in euthymic mice but was attenuated in athymic mice or in steroid-treated euthymic mice 28 days PI. Expression of Th2 cytokines interleukins 4, 5, and 13 was increased during the acute infection but not thereafter. COX-2 was localized to muscle and its enzymatic activity remained significantly increased in the muscle on day 28 PI. Selective COX-2 inhibition in vitro reduced the sustained increase in tension generation.

CONCLUSIONS

These findings show that COX-2 activation in resident cells of the muscularis externa contributes to the muscle hypercontractility that persists after infection.

Polymerase chain reaction detection of small round-structured viruses from two related hospital outbreaks of gastroenteritis using inosine-containing primers

Two outbreaks of gastroenteritis in the UK which occurred nine days apart at Lymington and Southampton hospitals were investigated. The clinical and epidemiological features of both outbreaks were characteristic of small round-structured virus (SRSV) infection with rapid onset of diarrhoea and/or nausea and vomiting and propagation of the outbreaks by secondary spread. SRSV particles were observed by immune electron microscopy (EM) in 60% of faecal samples from both outbreaks and no other pathogens were detected. The index case for the second outbreak was a patient who was admitted with diarrhoea and vomiting after being discharged from Lymington hospital during the first outbreak. The possibility that the two outbreaks were caused by the same strain of SRSV was investigated by the polymerase chain reaction (PCR). New inosine-containing PCR primers were designed to amplify the RNA polymerase region of SRSV cDNA from genetic groups I and II. The PCR using the group II primers achieved a higher detection rate for SRSVs in faecal samples (68% of samples positive from both outbreaks) than immune EM. SRSVs were not detected using the group I primers or using conventional degenerate PCR primers. The nucleotide sequences of PCR amplicons from both outbreaks were identical providing molecular epidemiological evidence for the involvement of a single SRSV strain. Comparison of the RNA polymerase region of this virus with the equivalent regions of genetic group I (69.4-75.0% amino acid identify) and genetic group II (88.9-100% amino acid and 77.1-88.1% nucleotide identity) SRSVs revealed that the causative SRSV was a distinct member of genetic group II.

Four PSM/SH2-B alternative splice variants and their differential roles in mitogenesis

An SH2 domain originally termed SH2-B had been identified as a direct cellular binding target of a number of mostly mitogenic receptors. The complete cellular protein, termed PSM, and respective sequence variants share additional Pro-rich and PH regions, as well as similarities with APS and Lnk. A role of these mediators has been implicated in signaling pathways found downstream of growth hormone receptor and receptor tyrosine kinases, including the insulin, insulin-like growth factor-I (IGF-I), platelet-derived growth factor (PDGF), nerve growth factor, hepatocyte growth factor, and fibroblast growth factor receptors. As a result of this report a total of four PSM/SH2-B sequence variants termed alpha, beta, gamma, and delta have now been identified in the mouse and have been compared with the available rat and human sequences. Variant differences are based on alternative splicing and define distinct last exons 7, 8, and 9 that result in reading frameshifts and unique carboxyl-terminal amino acid sequences. Variant sequences have been identified from cDNA libraries and directly by reverse transcription-polymerase chain reaction. Sequence analysis predicts four distinctly sized protein products that have been demonstrated after cDNA expression. All were found phosphorylated on tyrosine specifically in response to IGF-I and PDGF stimulation. cDNA expression of the four variants caused variant-dependent levels of stimulation of IGF-I- and PDGF-induced mitogenesis. The most pronounced increase in mitogenesis was consistently observed for the gamma variant followed by delta, alpha, and beta with decreasing responses. In contrast, the mitogenic response to epidermal growth factor consistently remained unaffected. The variants are expressed in most mouse tissues, typically, most strongly in pairs of alpha and delta or beta and gamma. Our findings implicate differential roles of the PSM/SH2-B splice variants in specific mitogenic signaling pathways.