Opposing functions of chondroitin sulfate and heparan sulfate during early neuronal polarization

Axon-dendrite polarity of neurons is essential for information processing in the nervous system. Here we studied the functions of chondroitin sulfate (CS) and heparan sulfate (HS) in neuronal polarization using cultured dissociated hippocampal neurons. Immunohistochemical analyses of early cultured neurons indicated the distribution of these glycosaminoglycans to be quite different. While CS epitopes were accumulated in the focal contacts present in axons and cell bodies, those of HS were detected ubiquitously on the cell surface including on dendrites and axons. Treatment with chondroitinase (CHase) ABC, which degrades CS, and knockdown of a CS sulfotransferase, N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase (4,6-ST), which is involved in the biosynthesis of oversulfated structures, induced the formation of multiple axons in hippocampal neurons. Time-lapse recordings revealed the multiple axons of CHase ABC-treated neurons to be highly unstable, extending and retracting, repeatedly. CHase ABC-treatments suggested that CS is involved in the formation of phosphorylated focal adhesion kinase-positive focal contacts. Thus, CS may enhance integrin signaling in the nascent axons, supporting axon specification. On the other hand, when neurons were treated with heparitinases that specifically degrade HS, neurons with a single axon increased. The axons of HSase-treated neurons extended steadily and showed almost no retraction. These results suggest that CS stabilizes and HS destabilizes the growth of axons in an opposing manner, contributing to early neuronal polarization.

Swine-origin influenza-virus-induced acute lung injury: Novel or classical pathogenesis?

Influenza viruses are common respiratory pathogens in humans and can cause serious infection that leads to the development of pneumonia. Due to their host-range diversity, genetic and antigenic diversity, and potential to reassort genetically in vivo, influenza A viruses are continual sources of novel influenza strains that lead to the emergence of periodic epidemics and outbreaks in humans. Thus, newly emerging viral diseases are always major threats to public health. In March 2009, a novel influenza virus suddenly emerged and caused a worldwide pandemic. The novel pandemic influenza virus was genetically and antigenically distinct from previous seasonal human influenza A/H1N1 viruses; it was identified to have originated from pigs, and further genetic analysis revealed it as a subtype of A/H1N1, thus later called a swine-origin influenza virus A/H1N1. Since the novel virus emerged, epidemiological surveys and research on experimental animal models have been conducted, and characteristics of the novel influenza virus have been determined but the exact mechanisms of pulmonary pathogenesis remain to be elucidated. In this editorial, we summarize and discuss the recent pandemic caused by the novel swine-origin influenza virus A/H1N1 with a focus on the mechanism of pathogenesis to obtain an insight into potential therapeutic strategies.

Selective control of type I IFN induction by the Rac activator DOCK2 during TLR-mediated plasmacytoid dendritic cell activation

Plasmacytoid dendritic cells (pDCs) play a key role in antiviral immunity, but also contribute to the pathogenesis of certain autoimmune diseases, by producing large amounts of type I IFNs. Although activation of pDCs is triggered by engagement of nucleotide-sensing toll-like receptors (TLR) 7 and 9, type I IFN induction additionally requires IκB kinase (IKK) α–dependent activation of IFN regulatory factor (IRF) 7. However, the signaling pathway mediating IKK-α activation is poorly defined. We show that DOCK2, an atypical Rac activator, is essential for TLR7- and TLR9-mediated IFN-α induction in pDCs. We found that the exposure of pDCs to nucleic acid ligands induces Rac activation through a TLR-independent and DOCK2-dependent mechanism. Although this Rac activation was dispensable for induction of inflammatory cytokines, phosphorylation of IKK-α and nuclear translocation of IRF-7 were impaired in Dock2-deficient pDCs, resulting in selective loss of IFN-α induction. Similar results were obtained when a dominant-negative Rac mutant was expressed in wild-type pDCs. Thus, the DOCK2–Rac signaling pathway acts in parallel with TLR engagement to control IKK-α activation for type I IFN induction. Owing to its hematopoietic cell-specific expression, DOCK2 may serve as a therapeutic target for type I IFN–related autoimmune diseases.

Insulin-mediated regulation of decidual protein induced by progesterone (DEPP) in adipose tissue and liver

We analyzed the profile of the genes expressed in human adipose tissue and identified the fat-derived molecules, adiponectin and aquaporin 7, which modulate glucose and lipid metabolism. The same Bodymap analysis revealed abundant expression of the decidual protein induced by progesterone (DEPP) in the white adipose tissue. Northern blot analysis confirmed that human DEPP mRNA was highly expressed in white adipose tissue. Mouse DEPP mRNA was detected in heart, lung, skeletal muscle, and white adipose tissue under feeding state. In contrast, under fasting state, mouse DEPP mRNA was enhanced in lung, skeletal muscle, and white adipose tissue and it appeared also in the liver and kidney, suggesting up regulation of DEPP by fasting. Because fasting-induced DEPP expression was observed in insulin-sensitive organs, we investigated the regulation of DEPP in white adipose tissue and liver. During adipogenesis of mouse 3T3-L1 cells, DEPP mRNA increased in a differentiation-dependent manner similar to adiponectin and aquaporin 7. Treatment of cultured 3T3-L1 mature adipocytes, rat H4IIE, and human HepG2 hepatoma cells with insulin significantly decreased DEPP mRNA levels in dose- and time-dependent manners. IN VIVO experiments showed significant decrease of hepatic and adipose DEPP mRNA levels in refed mice, compared to fasted animals, and also showed significant increase in DEPP mRNA in streptozotocin-induced insulin-deficient diabetic mice. These results indicate that DEPP is a novel insulin-regulatory molecule expressed abundantly in insulin-sensitive tissues including white adipose tissue and liver.

Ginsenoside Rb(1) prevents image navigation disability, cortical infarction, and thalamic degeneration in rats with focal cerebral ischemia

Oral administration of red ginseng powder before but not after transient forebrain ischemia prevents delayed neuronal death in gerbils. One neuroprotective molecule within red ginseng powder is ginsenoside Rb(1). The mechanism of action(s) of ginsenoside Rb(1) remains to be determined. We performed intracerebroventricular infusion of 0.6 microg/d ginsenoside Rb(1) before or after permanent occlusion of the left middle cerebral artery in stroke-prone spontaneous hypertensive rats. Ginsenoside Rb(1) significantly decreased escape latency on repeated trials of the Morris water maze test, throughout the first to fourth trial days at 2 and 4 weeks after MCA occlusion (P<.05, P<.01 or P<.001). The ratio of the infarcted area to the left hemispheric area in the groups treated with 0.6 microg/d of ginsenoside Rb(1) was significantly smaller than that in the saline-treated ischemic group (P<.05 or P<.001). The continuous infusion of ginsenoside Rb(1) (0.06 microg/d) was less effective and the other doses examined were ineffective in ameliorating ischemia-induced image navigation disability and reducing cortical infarct size. There were significant differences in neuron numbers in the ventroposterior thalamic nucleus and in the left-to-right ratio of the thalamic area between the saline-infused ischemic group and the ginsenoside Rb(1)-treated ischemic group (P<.05 or P<.01). Moreover, ginsenoside Rb(1) at concentrations of 0.1 to 100 fg/mL (0.09 to 90 fM), facilitated neurite extension and rescued cortical neurons from lethal damage caused by the free radical-promoting agent FeSO(4), in vitro (P<.05 or P<.01). These findings suggest that ginsenoside Rb(1) protects the cerebral cortex against lethal ischemic damage possibly by acting as a neurotrophic factor-like agent and by scavenging free radicals, which are overproduced in situ during and after brain ischemia. The final link between the in vivo neuroprotective action and the in vitro neurotrophic and antioxidant activities of ginsenoside Rb(1) remains to be determined.

Bacterial interactions in dental biofilm development

Recent analyses with ribosomal RNA-based technologies have revealed the diversity of bacterial populations within dental biofilms, and have highlighted their important contributions to oral health and disease. Dental biofilms are exceedingly complex and multispecies ecosystems, where oral bacteria interact cooperatively or competitively with other members. Bacterial interactions that influence dental biofilm communities include various different mechanisms. During the early stage of biofilm formation, it is known that planktonic bacterial cells directly attach to surfaces of the oral cavity or indirectly bind to other bacterial cells that have already colonized. Adherence through co-aggregation may be critical for the temporary retention of bacteria on dental surfaces, and may facilitate eventual bacterial colonization. It is likely that metabolic communication, genetic exchange, production of inhibitory factors (e.g., bacteriocins, hydrogen peroxide, etc.), and quorum-sensing are pivotal regulatory factors that determine the bacterial composition and/or metabolism. Since each bacterium can easily access a neighboring bacterial cell and its metabolites, genetic exchanges and metabolic communication may occur frequently in dental biofilms. Quorum-sensing is defined as gene regulation in response to cell density, which influences various functions, e.g., virulence and bacteriocin production. In this review, we discuss these important interactions among oral bacteria within the dental biofilm communities.

Predicting the probability for fall incidence in stroke patients using the Berg Balance Scale

This observational study investigated the relationship between balance, mobility and falls in 72 hemiplegic stroke inpatients, with the aim of developing a model for predicting fall risk. Fall history was recorded by interview, balance was assessed using the Berg Balance Scale (BBS) and activities of daily living were evaluated using the Functional Independence Measure (FIM). Variables differing between fallers and non-fallers were identified, and a stepwise regression analysis was performed to identify a combination of variables that effectively predicted fall status. Fallers (occasional and repeat; n = 27) had a shorter time from stroke onset, lower FIM scores on admission and discharge, lower BBS and Mini-Mental State Examination scores, a greater age and longer length of hospital stay compared with non-fallers (all differences were significant). A logistic model for predicting falls showed that BBS at admission was significantly related to falls, with fallers having lower BBS scores at admission (cut-off <or= 29; sensitivity 80%; specificity 78%). These data suggest BBS is a sensitive and specific measure for identifying stroke patients at risk of falling.

Functional difference of receptor-type protein tyrosine phosphatase zeta/beta isoforms in neurogenesis of hippocampal neurons

Receptor-type protein tyrosine phosphatase zeta/beta (RPTPzeta) is a transmembrane chondroitin sulfate proteoglycan (CSPG) and has been shown to play crucial roles in controlling axonal growth and neuronal migration. The RPTPzeta has two transmembranous isoforms, shorter receptor form of RPTPzeta (sRPTPzeta) and full-length receptor form of RPTPzeta (fRPTPzeta), but no studies have been reported about functional difference of these two isoforms. In the present study, therefore, we examined whether or not two RPTPzeta isoforms have different role in controlling dendritic morphology and synaptic number in cultured hippocampal neurons using the quantitative morphometrical analysis. Confocal microscopic observation showed that the immunoreactivity of RPTPzeta was observed throughout cells such as axons, growth cones, and dendrites at the early stages of neuronal culture, while it was seen predominantly on dendrites at the late stages. Western blotting analysis revealed that fRPTPzeta was mainly expressed at the early stages of culture and both RPTPzeta isoforms were expressed at late stages of culture. The overexpression of sRPTPzeta in hippocampal neurons increased the dendritic arborization without altering the average length of dendritic branches, whereas that of fRPTPzeta decreased the dendritic arborization and increased the average length of dendritic branches. The RNA interference of fRPTPzeta expression increased the dendritic arborization without altering the average length of dendritic branches. The overexpression of fRPTPzeta decreased the density of hippocampal dendritic synapses, but that of sRPTPzeta had no effects. Pleiotrophin, a ligand for RPTPzeta to interfere the phosphatase activity, increased the density of hippocampal dendritic synapses. Thus, the present study demonstrates that two transmembranous RPTPzeta isoforms have different functions for regulating dendritogenesis and synaptogenesis.

Susceptibility of human T-cell leukemia virus type I-infected cells to humanized anti-CD30 monoclonal antibodies in vitro and in vivo

Adult T-cell leukemia (ATL) is an aggressive malignancy of activated CD4(+) T cells associated with human T-cell leukemia virus type I (HTLV-I) infection. No conventional chemotherapy regimen has appeared successful in patients with ATL, thus establishing effective therapy is urgently required. In some cases, ATL tumor cells express CD30 on the cell surface, therefore, a therapy with mAb against CD30 would be beneficial. To investigate the effect of CD30-mediated therapy on ATL, we assessed SGN-30, a chimeric anti-CD30 mAb, and SGN-35, a monomethyl auristatin E-conjugated anti-CD30 mAb, in vitro and in vivo. Three HTLV-I-infected cell lines were co-cultured with SGN-30 or SGN-35, and the growth-inhibitory effects on the HTLV-I-infected cells were evaluated using an in vitro cell proliferation assay and cell cycle analysis. SGN-30 and SGN-35 showed growth-inhibitory activity against the HTLV-I-infected cell lines by apoptosis and/or cell growth arrest in vitro. To further investigate the effects of SGN-30 and SGN-35 on HTLV-I-infected cells in vivo, we used NOD/SCID mice subcutaneously engrafted with HTLV-I-infected cells. Both mAbs significantly inhibited the growth of HTLV-I-infected cell tumors in the NOD/SCID murine xenograft models. These data suggest that CD30-mediated therapy with SGN-30 or SGN-35 would be useful for patients with ATL.

Analysis of soluble vascular endothelial growth factor receptor-1 secreted from cultured corneal and oral mucosal epithelial cell sheets in vitro

BACKGROUND

In clinical trials, eyes transplanted with cultured oral mucosal epithelial cell sheets have shown increased neovascularisation compared with eyes treated with cultured corneal epithelial cell sheets. As reported recently, soluble vascular endothelial growth factor receptor-1 (soluble VEGFr-1) is a main factor to maintain a corneal avascularity.

AIM

To investigate soluble VEGFr-1 of cultured corneal epithelial cells (CCE) and cultured oral mucosal epithelial cells (COE) in vitro.

METHODS

Rabbit corneal and oral mucosal epithelial cells were co-cultured with mitomycin C-treated NIH/3T3 cells on culture plates. After CCE and COE were multilayered, culture medium was replaced by basal medium and incubated. Protein secretion of soluble VEGFr-1 was assessed in conditioned medium from CCE and COE by ELISA. Angiogenic potential was examined by invasion, migration assays with human umbilical vein endothelial cells (HUVECs) in addition to recombinant soluble VEGFr-1.

RESULTS

CCE secreted a significantly higher amount of soluble VEGFr-1 than did COE. Recombinant soluble VEGFr-1 significantly suppressed HUVEC migration induced by COE, without suppression in CCE. In conclusion, these findings suggest that low protein levels of soluble VEGFr-1 may lead to corneal neovascularisation after COE sheet transplantation.

Sentinel lymph node detection in breast cancer patients by real-time virtual sonography constructed with three-dimensional computed tomography-lymphography

Abstract #1026

Background: Ultrasonography (US) is one tool for preoperative diagnosis of lymph node metastases in breast cancer. However, US cannot detect true sentinel lymph nodes (SLNs).&#x2028; Methods: We identified SLNs in 60 clinically node-negative breast cancer patients using a real-time virtual sonography (RVS) system to display in real time a virtual multi-planar reconstruction obtained from computed tomography (CT) volume data corresponding to the same cross-sectional image from US. CT volume data were obtained from our original three-dimensional CT lymphography (3DCT-LG), which accurately detects SLNs in breast cancer. SLN metastases were assessed by shape and visibility of the hilum. All patients underwent SLN biopsy and SLN metastases were examined pathologically.&#x2028; Results: In all 60 patients, we were able to detect the same SLNs visualized by 3DCT-LG. Suspicious SLN metastases were identified in 7 of the 60 patients, and 4 of 7 patients were pathologically positive. Positive predictive value was 57%. The remaining 53 patients displayed non-suspect SLNs in which absence of metastasis from the SLN was confirmed histologically. Overall accuracy was 95%.&#x2028; Conclusions: This is a first attempt at preoperatively identifying SLNs using US guided by the RVS system in breast cancer patients. Although evaluation of SLN metastases was unsatisfactory, this method may be useful for preoperative fine-needle aspiration cytology for diagnosis of SLN metastases.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1026.

Oncogenesis by retroviruses: old and new paradigms

Retroviruses are associated with a variety of diseases including an array of malignancies, immunodeficiencies and neurological disorders. In particular, studies of oncogenic retroviruses established fundamental principles of modern molecular cancer biology. Studies of avian Rous sarcoma virus (RSV) led to the discovery of the viral oncogene src, and this was followed by the discovery of other viral oncogenes in retroviruses of mammals including rodents, cats, monkeys and so forth. Studies of the viral oncogenes in turn led to the discovery of cellular proto-oncogenes in the host genome; cellular oncogenes have been shown to be activated in a variety of human cancers, including those with no viral involvement. Oncogenic animal retroviruses can be divided into two groups based on their mechanisms of tumourigenesis, acute transforming retroviruses and nonacute retroviruses. Acute transforming retroviruses are typically replication defective and they induce tumours rapidly due to expression of their viral oncogenes. Nonacute retroviruses are replication competent and they induce tumours with longer latencies, by activating cellular proto-oncogenes in the tumour cells; this results from insertion of proviral DNA in the vicinity of the activated proto-oncogene. More recently, human T-cell leukaemia virus type I (HTLV-I) was discovered as an etiological agent of human cancer (adult T-cell leukaemia [ATL]); this virus also encodes regulatory genes some of which are important for its oncogenic potential. Most recently, the retroviral structural protein Envelope (Env) has been shown to be directly involved in oncogenic transformation for certain retroviruses. Env-induced transformation is a new paradigm for retroviral oncogenesis. In this review, we will summarise research on retrovirus oncogenic transformation over the past 100 years since the first published report of an oncogenic virus with particular attention to Env-induced transformation.

Differential modulation of diet-induced obesity and adipocyte functionality by human apolipoprotein E3 and E4 in mice

OBJECTIVE

Apolipoprotein E (apoE), a key protein in lipid metabolism, is highly expressed in adipose tissues. Studies have shown that human APOE*4 is associated with a lower body mass index but with a greater risk of coronary heart disease compared with other APOE alleles. To define the isoform-specific role of apoE in regulating the expandability and functionality of adipose tissues, we investigated the effects of diet-induced obesity in mice whose endogenous Apoe gene has been replaced by either the human APOE*3 or APOE*4 allele.

RESULTS

After 8 weeks on a Western-type high-fat diet, male APOE4 mice displayed impaired tolerance to glucose and fat overload compared with APOE3 mice. Subcutaneous fat tissues in APOE4 and APOE3 mice after high fat feeding were not different. In contrast, although epididymal fat tissues in APOE4 mice gained 30% less weight during the high fat feeding than in APOE3 mice, they showed impaired insulin-stimulated glucose uptake ex vivo. Epididymal APOE4 adipocytes were larger in size than APOE3 adipocytes, and expressed reduced levels of mRNA for peroxisome proliferator-activated receptor gamma2 and adiponectin, important markers of adipocyte functionality. Adenoviral expression of apoE3 in apoE-null culture adipocytes induced adiponectin mRNA in a dose-dependent manner, but the induction was significantly blunted in cells overexpressing apoE4. However, in contrast to the apoE3-expressing cells, Glut1, but not Glut4, expression levels were positively correlated with increased apoE4 mRNA, suggesting that apoE4 expression in adipocyte interferes in insulin-sensing pathways.

CONCLUSION

Dysfunctional epididymal adipose tissues contribute to the accelerated impairment of glucose tolerance in APOE4 mice fed a Western-type diet. Our results underscore the importance of functionality of individual fat depots rather than total fat mass as a determinant for metabolic disturbance during diet-induced obesity.

Efficacy of recombinant bacille Calmette-Guérin vaccine secreting interleukin-15/antigen 85B fusion protein in providing protection against Mycobacterium tuberculosis

Protection against Mycobacterium tuberculosis not only depends on CD4+ T helper type 1 (Th1) cells but, also, on CD8+ T cells. Interleukin (IL)-15 has an important function in the maintenance of memory CD8+ T cells. In the present study, we examined the efficacy of recombinant Mycobacterium bovis bacille Calmette-Guérin (rBCG) secreting fusion protein antigen (Ag) 85B murine IL-15 (rBCG-Ag85B-IL15) in providing protection against M. tuberculosis infection. The levels of major histocompatibility (MHC) class Ib (H2-M3)-binding TB2- or MHC class Ia (H-2Db)-binding MPT64-specific CD8+ T cells producing interferon (IFN)-gamma were significantly higher after immunization with rBCG-Ag85B-IL15 than after immunization with rBCG secreting Ag85B (rBCG-Ag85B). The levels of purified protein derivative- or Ag85B-specific CD4+ T cells producing IFN-gamma were also higher in mice immunized with rBCG-Ag85B-IL15 than in mice immunized with rBCG-Ag85B. Mice immunized with rBCG-Ag85B-IL15 exhibited CD8+ and CD4+ T cells responses that were stronger than those in mice immunized with rBCG-Ag85B, as well as robust protection in the lung against intratracheal challenge of M. tuberculosis. Thus, rBCG-Ag85B-IL15 vaccination capable of inducing efficient cell-mediated immunity might be used as an effective vaccine for tuberculosis.

Effects of the time interval between clamping and linear stapling for resection of porcine small intestine

BACKGROUND

Although a wait of several seconds after clamping is recommended when an automatic stapler is used to achieve adequate hemostasis, this wait has not been experimentally clarified.

METHODS

To determine whether waiting is necessary between clamping and firing of a linear stapler, this study evaluated the number of staple line bleeding points and histologic changes in stapling sites of porcine small intestine (n = 46). It also assessed the ratio of dry to wet tissue weight (DW ratio) (n = 20) of porcine small intestine clamped between the prongs of a linear stapler. The sites were studied separately as follows: no wait with a four-row device (n = 12), no wait with a six-row device (n = 11), wait with a four-row device (n = 12), and wait with a six-row device (n = 11). The linear stapler was fired immediately after clamping in the no wait group and 1 min after clamping in the wait group.

RESULTS

The mean number of staple line bleeding points in 2 to 5 min with the six-row device and in 3 to 5 min with the four-row device after firing were significantly less in the wait group than in the no wait group using the same device (p < 0.05). Cross sections of staple lines showed a higher frequency of mucosal cutting in the no wait group than in the wait group for both the four-row and the six-row devices (both significant at p < 0.01). Although the mean wet tissue weights of anastomotic sites did not change in either group, the mean DW ratio was significantly less in the wait group than in the no wait group (p < 0.01).

CONCLUSIONS

A 1-min interval after clamping decreases the amount of clamped tissue. Waiting may thus be necessary to reduce bleeding from stapling sites, which may be related to a decrease in mucosal cutting.

Reduction of vitamin K concentration by salivary Bifidobacterium strains and their possible nutritional competition with Porphyromonas gingivalis

AIMS

To assess the possibility that bifidobacteria compete with Porphyromonas gingivalis for their mutual growth factor vitamin K. This study also examined whether salivary Bifidobacterium species decrease vitamin K concentration in the growth medium.

METHODS AND RESULTS

Sixty-five strains of Bifidobacterium were obtained from 20 of 24 periodontally healthy subjects. Bifidobacterium dentium was most frequently detected in the saliva of subjects, followed by Bifidobacterium adolescentis, Bifidobacterium longum, and Bifidobacterium urinalis. The growth of most Bifidobacterium isolates, except that of B. urinalis, was stimulated by vitamin K. Moreover, the isolates were capable of decreasing vitamin K after incubation, which suggests that bifidobacteria compete with P. gingivalis for vitamin K. In a co-culture, a representative strain -B. adolescentis S2-1 - inhibited the growth of P. gingivalis if it was inoculated in the medium before P. gingivalis.

CONCLUSIONS

B. adolescentis S2-1 decreased vitamin K concentration and inhibited the growth of P. gingivalis by possibly competing for the growth factor.

SIGNIFICANCE AND IMPACT OF THE STUDY

Salivary bifidobacteria may possess the potential to suppress the growth of P. gingivalis by reducing the growth factor(s) in the environment.