Localization of tobacco germin-like protein 1 in leaf intercellular space

To characterize leaf cell wall proteins relating the architectural changes of leaves, we analyzed Nicotiana tabacum leaf cell wall proteins that were extracted by the treatment with lithium chloride. Some of these proteins showed amino acid sequence homology to some germin-like proteins (GLP). Based of those sequences, we isolated the cDNA encoding the GLPs (NtGLP1-1, NtGLP2-1). Phylogenetic analysis including de novo assembled tobacco GLPs using EST clones, revealed that tobacco GLPs belong to at least 5 different subgroups of GLP and both NtGLP1 and NtGLP2 belong to GLP subfamily 3. We showed that the NtGLP1 actually localizes to cell wall and revealed that it predominantly localized at specific sites on the leaf cell wall where intercellular attachment was just bifurcated. Expression of the NtGLP1 mRNA was mainly detected in leaves especially at elongating stage. NtGLP1 is possibly relevant to development of leaf intercellular space.

Development of multichannel low-energy neutron spectrometer

A multichannel low-energy neutron spectrometer for down-scattered neutron (DSN) measurements in inertial confinement fusion (ICF) experiments has been developed. Our compact-size 256-channel lithium-glass-scintillator-based spectrometer has been implemented and tested in ICF experiments with the GEKKO XII laser. We have performed time calibration of the 256-channel analog-to-digital convertor system used for DSN measurements via X-ray pulse signals. We have clearly observed the DD-primary fusion neutron signal and have successfully studied the detector's impulse response. Our detector is soon to be implemented in future ICF experiments.

Cyclic nucleotide phosphodiesterases: important signaling modulators and therapeutic targets

By catalyzing hydrolysis of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), cyclic nucleotide phosphodiesterases are critical regulators of their intracellular concentrations and their biological effects. As these intracellular second messengers control many cellular homeostatic processes, dysregulation of their signals and signaling pathways initiate or modulate pathophysiological pathways related to various disease states, including erectile dysfunction, pulmonary hypertension, acute refractory cardiac failure, intermittent claudication, chronic obstructive pulmonary disease, and psoriasis. Alterations in expression of PDEs and PDE-gene mutations (especially mutations in PDE6, PDE8B, PDE11A, and PDE4) have been implicated in various diseases and cancer pathologies. PDEs also play important role in formation and function of multimolecular signaling/regulatory complexes, called signalosomes. At specific intracellular locations, individual PDEs, together with pathway-specific signaling molecules, regulators, and effectors, are incorporated into specific signalosomes, where they facilitate and regulate compartmentalization of cyclic nucleotide signaling pathways and specific cellular functions. Currently, only a limited number of PDE inhibitors (PDE3, PDE4, PDE5 inhibitors) are used in clinical practice. Future paths to novel drug discovery include the crystal structure-based design approach, which has resulted in generation of more effective family-selective inhibitors, as well as burgeoning development of strategies to alter compartmentalized cyclic nucleotide signaling pathways by selectively targeting individual PDEs and their signalosome partners.

Multiple roles of the PGE2 -EP receptor signal in vascular permeability

BACKGROUND AND PURPOSE

PGE2 is a major prostanoid that regulates inflammation by stimulating EP1-4 receptors. However, how PGE2 induces an initial inflammatory response to vascular hyper-permeability remains unknown. Here we investigated the role of the PGE2 -EP receptor signal in modulating vascular permeability both in vivo and in vitro.

EXPERIMENTAL APPROACH

We used a modified Miles assay and intravital microscopy to examine vascular permeability in vivo. Endothelial barrier property was assessed by measuring transendothelial electrical resistance (TER) in vitro.

KEY RESULTS

Local administration of PGE2 , an EP2 or EP4 receptor agonist into FVB/NJcl mouse ear skin caused vascular leakage, indicated by dye extravasation. Intravital microscopy and laser Doppler blood-flow imaging revealed that these treatments dilated peripheral vessels and increased local blood flow. Pretreatment with the vasoconstrictor phenylephrine inhibited the PGE2 -induced blood flow increase and vascular leakage. In contrast to the EP2 and EP4 receptor agonists, administration of an EP3 receptor agonist suppressed vascular leakage without altering vascular diameter or blood flow. In isolated HUVECs, the EP3 receptor agonist elevated TER and blocked thrombin-induced dextran passage. Inhibiting PKA restored the hypo-permeability induced by the EP3 receptor agonist.

CONCLUSIONS AND IMPLICATIONS

Activation of the PGE2 -EP2 or -EP4 receptor signal induces vasodilatation in mural cells, resulting in increased local blood flow and hyper-permeability. In contrast, activation of the PGE2 -EP3 receptor signal induces a cAMP-dependent enhancement of the endothelial barrier, leading to hypo-permeability. We provide the first evidence that endothelial cells and mural cells cooperate to modulate vascular permeability.

PDGF and TGF-β promote tenascin-C expression in subepithelial myofibroblasts and contribute to intestinal mucosal protection in mice

BACKGROUND AND PURPOSE

Tenascin-C (TnC) is a multi-domain extracellular matrix glycoprotein that is expressed at a high level during embryogenesis but is almost absent during normal postnatal life. This multi-domain complex molecule is reported to associate with both pro-inflammatory and anti-inflammatory signalling cascades. In this study, we examined how TnC modulated intestinal inflammation.

EXPERIMENTAL APPROACH

TnC pathophysiology was evaluated in cultures of rat intestinal subepithelial myofibroblasts (ISEMF) and intestinal epithelial cells. Wild-type and TnC(-/-) mice were treated with dextran sodium sulfate (DSS) to induce colitis.

KEY RESULTS

DSS-induced colitis in mice markedly increased TnC in the damaged mucosal areas and up-regulated mRNA for TnC, pro-inflammatory cytokines and growth factors (PDGF-B and TGF-β1). In addition, 2,4,6-trinitrobenzene sulfonic acid-induced colitis and SAMP1/Yit mice, a model of spontaneous Crohn's disease, also exhibited increased mucosal TnC in colon and ilea respectively. PDGF receptor-α (PDGFRα) positive ISEMF were the primary TnC-producing cells in colon tissues. Accordingly, ISEMF collected from the rat colon constitutively expressed both TnC and PDGFRα. PDGF-BB and TGF-β1 up-regulated both TnC mRNA and protein levels in ISEMF. Knock-down of TnC gene increased susceptibility to DSS-induced colitis, compared with TnC(+/+) littermates. TnC(-/-) mice showed marked abrasion of intestinal mucosal barrier and increased inflammatory scores. Moreover, TnC accelerated both trans-well migration and wound healing in epithelial cells.

CONCLUSIONS AND IMPLICATIONS

The pharmacological profiles of PDGF-BB and TGF-β in colitis tissues and ISEMF suggest that increased TnC production during inflammation contributed to epithelial cell migration, remodelling and protection of intestinal barriers.

MR imaging of subcallosal artery infarct causing amnesia after surgery for anterior communicating artery aneurysm

BACKGROUND AND PURPOSE

During surgery to treat an aneurysm in the anterior communicating artery, injury to the subcallosal artery, a perforator of the anterior communicating artery, may lead to infarction that produces basal forebrain amnesia after surgery. Our purpose was to examine whether 3D MR imaging can detect subcallosal artery infarction in patients with amnesia after surgery for an anterior communicating artery aneurysm.

MATERIALS AND METHODS

We evaluated 3D-T2-weighted MR images obtained a median of 4 months after treatment of anterior communicating artery aneurysm for the presence of infarcted foci in 10 consecutive patients with postoperative amnesia. Because the subcallosal artery and its neighboring perforator, the recurrent artery of Heubner, were considered the most easily affected vessels during that surgery, we focused mainly on 8 regions of the subcallosal artery territory per hemisphere and 5 regions of the recurrent artery of Heubner territory per hemisphere.

RESULTS

All 10 patients had infarcts in the territory of the subcallosal artery (median, 9 regions per patient), and most were bilateral (9 of 10 patients). Five patients had additional infarcted foci in the territory of the recurrent artery of Heubner (median, 1 region per patient), all unilateral. Among the regions perfused by the subcallosal artery, the column of the fornix was involved in all patients; the anterior commissure, in 9; and the paraterminal gyrus, in 8 patients.

CONCLUSIONS

3D MR imaging revealed subcallosal artery infarction, the distribution of which was mostly bilateral, presumably owing to the unpairedness of that artery, in patients with postoperative amnesia after anterior communicating artery aneurysm repair.

Black hole restenosis after drug-eluting stent implantation for in-stent restenosis: potential mechanism and optimal strategy

In-stent restenosis (ISR) has long remained as the major limitation of coronary stenting. The use of drug-eluting stent (DES) reduces the risk of repeat revascularization without an increase of death and myocardial infarction, compared to the standard bare metal stents. DES has also demonstrated markedly to reduce ISR for complex lesions. However, ISR after DES implantation still occurs and optimal treatment for ISR after DES has not been established. Herein, we report 3 cases with black hole restenosis confirmed by intravascular ultrasound at the site of overlapped DES and discuss potential mechanism and optimal strategy for this phenomenon.

WOX13-like genes are required for reprogramming of leaf and protoplast cells into stem cells in the moss Physcomitrella patens

Many differentiated plant cells can dedifferentiate into stem cells, reflecting the remarkable developmental plasticity of plants. In the moss Physcomitrella patens, cells at the wound margin of detached leaves become reprogrammed into stem cells. Here, we report that two paralogous P. patens WUSCHEL-related homeobox 13-like (PpWOX13L) genes, homologs of stem cell regulators in flowering plants, are transiently upregulated and required for the initiation of cell growth during stem cell formation. Concordantly, Δppwox13l deletion mutants fail to upregulate genes encoding homologs of cell wall loosening factors during this process. During the moss life cycle, most of the Δppwox13l mutant zygotes fail to expand and initiate an apical stem cell to form the embryo. Our data show that PpWOX13L genes are required for the initiation of cell growth specifically during stem cell formation, in analogy to WOX stem cell functions in seed plants, but using a different cellular mechanism.

Contribution of NAC transcription factors to plant adaptation to land

The development of cells specialized for water conduction or support is a striking innovation of plants that has enabled them to colonize land. The NAC transcription factors regulate the differentiation of these cells in vascular plants. However, the path by which plants with these cells have evolved from their nonvascular ancestors is unclear. We investigated genes of the moss Physcomitrella patens that encode NAC proteins. Loss-of-function mutants formed abnormal water-conducting and supporting cells, as well as malformed sporophyte cells, and overexpression induced ectopic differentiation of water-conducting-like cells. Our results show conservation of transcriptional regulation and cellular function between moss and Arabidopsis thaliana water-conducting cells. The conserved genetic basis suggests roles for NAC proteins in the adaptation of plants to land.

Imaging the mitotic spindle by spinning disk microscopy in tobacco suspension cultured cells

Plants are valuable systems for analyzing the acentriolar mitotic spindle. We have developed methods for imaging the mitotic spindle in living tobacco (Nicotiana tabacum) suspension culture cells expressing GFP-α-tubulin. The methods allow the spindle to be observed in living cells at high spatial and temporal resolution and rely on water immersion objectives, spinning disk optics, and high-sensitivity cameras. Here, we describe these methods and provide step-by-step protocols for certain key steps. We also describe a method for application and removal of inhibitors.

The role of dynamic instability in microtubule organization

Microtubules are one of the three major cytoskeletal components in eukaryotic cells. Heterodimers composed of GTP-bound α- and β-tubulin molecules polymerize to form microtubule protofilaments, which associate laterally to form a hollow microtubule. Tubulin has GTPase activity and the GTP molecules associated with β-tubulin molecules are hydrolyzed shortly after being incorporated into the polymerizing microtubules. GTP hydrolysis alters the conformation of the tubulin molecules and drives the dynamic behavior of microtubules. Periods of rapid microtubule polymerization alternate with periods of shrinkage in a process known as dynamic instability. In plants, dynamic instability plays a key role in determining the organization of microtubules into arrays, and these arrays vary throughout the cell cycle. In this review, we describe the mechanisms that regulate microtubule dynamics and underlie dynamic instability, and discuss how dynamic instability may shape microtubule organization in plant cells.

Abstract P6-06-43: Clinicopathological features of breast cancer patients with late recurrences

[Background]

With advances in early detection and improvements in treatments, long-term breast cancer survivors who had risk of late recurrence are increasing. Recent trials suggested 10 years of endocrine treatment produces a further reduction in recurrence and mortality rather than 5 years treatment. However, it remains to be elucidated which patients would have clinical benefit from longer endocrine treatment. We investigated clinicopathological features of breast cancer patients with late recurrences.

[Patients and Methods]

From 1989 to 2003, 1051 patients with primary breast cancer were treated at Keio University Hospital and classified into three groups: early recurrences (within 5 years), late recurrences (after 5 years) and no recurrences. Clinicopathological features of breast cancer patients with early and late recurrences were compared. Differences in frequency distribution were compared by the chi-squared test. Smoothed hazards estimates were used for estimation of recurrence rates depending on time.

[Results]

Among 1051 patients, 193 (18.4%) had early recurrences and 113 (10.8%) had late recurrences. Of all 306 recurrent patients, primary recurrent site was lung (24.2%), liver (8.8%), bone (20.0%), brain (1.3%), loco-regional (34.6%), distant lymph node (5.6%) and others (5.6%). Compared to patients with early recurrences, patients with late recurrences showed higher rate of positive hormone receptor (HR) status (58.0% vs. 81.4%, p<0.001), lower rate of pathological nodal involvement (68.4% vs. 54.0%, p = 0.016), lower rate of lymphovascular invasion (LVI) (81.3% vs. 65.5%, p = 0.003) and smaller tumor size (2.99 cm vs. 2.46 cm, p = 0.005).

For node-positive patients, the hazard of estimates was similar between the HR-positive and HR-negative groups beyond 5 years. For node-negative patients, however, the hazard of HR-positive patients increased consistently, crossed with the hazard of HR-negative patients between 5 and 6 years and was higher than the hazard of HR-negative patients beyond 6 years.

Among 204 HR-positive recurrent patients, 112 (54.9%) had early recurrences and 92 (45.1%) had late recurrences. Compared to HR-positive patients with early recurrences, HR-positive patients with late recurrences had lower rate of pathological nodal involvement (71.4% vs. 55.4%, p = 0.026) and lower rate of LVI (81.3% vs. 66.3%, p = 0.023), however, tumor size was not significantly correlated with late recurrences of HR-positive patients. On the other hand, no clinicopathological factors including pathological nodal status, LVI and tumor size were significantly correlated with late recurrences among 102 HR-negative recurrent patients.

Among 193 patients with early recurrences, HR-positive patients had significantly longer post-recurrence survival than HR-negative patients (99.1 months vs. 60.0 months, p<0.001). However, among 113 patients with late recurrences, post-recurrence survival of HR-positive patients was not significantly different from HR-negative patients (233.1 months vs. 231.2 months, p = 0.797).

[Conclusions]

These data suggested breast cancer patients with positive HR and negative nodal status had a high likelihood of developing late recurrences and should be treated with longer endocrine treatment.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-06-43.

Glucagon underutilized among type 1 diabetes mellitus patients in Japan

AIM

Glucagon is recommended to treat severe hypoglycemia in nonhospital environments, when a patient with type 1 diabetes mellitus (T1DM) is unconscious and unable to eat or drink. However, the actual possession rate of glucagon in Japan has not been investigated.

SUBJECTS AND METHODS

We recruited 208 T1DM patients older than 15 years of age. The patients were treated at 16 hospitals and clinics in different regions of Japan. Answers were obtained using a self-administered questionnaire about the possession, the experience of usage, and the preference to possess glucagon after reading what is glucagon and when it is used. A stepwise logistic regression analysis was performed to assess the influence of various factors on the possession of glucagon.

RESULTS

The possession rate of glucagon was 15.9%, and the rate of those who had experience of using glucagon to treat severe hypoglycemia was 6.0%. The rate of preference to possess glucagon at home after reading the description of glucagon was 39.0%. The possession of glucagon was significantly associated with results of the Glucagon Knowledge Test (odds ratio=24.1; 95% confidence interval, 3.2-183.3; P=0.002) and the history of severe hypoglycemia within 1 year (odds ratio=4.8; 95% confidence interval, 2.0-12.0; P=0.001).

CONCLUSIONS

Glucagon as a measure to treat severe hypoglycemia was underutilized among T1DM patients in Japan.

KNOX2 genes regulate the haploid-to-diploid morphological transition in land plants

Unlike animals, land plants undergo an alternation of generations, producing multicellular bodies in both haploid (1n: gametophyte) and diploid (2n: sporophyte) generations. Plant body plans in each generation are regulated by distinct developmental programs initiated at either meiosis or fertilization, respectively. In mosses, the haploid gametophyte generation is dominant, whereas in vascular plants-including ferns, gymnosperms, and angiosperms-the diploid sporophyte generation is dominant. Deletion of the class 2 KNOTTED1-LIKE HOMEOBOX (KNOX2) transcription factors in the moss Physcomitrella patens results in the development of gametophyte bodies from diploid embryos without meiosis. Thus, KNOX2 acts to prevent the haploid-specific body plan from developing in the diploid plant body, indicating a critical role for the evolution of KNOX2 in establishing an alternation of generations in land plants.

Neuropeptide Y loses its orexigenic effect in rats with lesions of the hypothalamic paraventricular nucleus

BACKGROUND

Both neuropeptide Y (NPY) and ghrelin can enhance the feeding behavior. The purpose of this study was to determine whether NPY and ghrelin are involved in hyperphagia and obesity induced by lesions of the hypothalamic paraventricular nucleus (PVN).

METHODS

Sham-operated control rats and rats subjected to bilateral electrolytic lesions of the PVN were administered NPY (5 μg/rat) by intracerebroventricular infusion or ghrelin (20 μg/kg) by intraperitoneal (i.p.) injection. Control rats were administered the appropriate vehicle by the same route as the drug. We measured the cumulative food intake (FI) for 2 h after infusion of NPY and for 4 h after ghrelin injection.

RESULTS

NPY significantly increased the cumulative FI in sham-operated rats. In PVN-lesioned rats, however, the cumulative FI at each time point (15 min, 30 min, 1 h, and 2 h) after NPY infusion was not significantly different from vehicle infusion, showing that NPY lost its orexigenic effect in PVN-lesioned rats. Following ghrelin injection, the cumulative FI was greater in PVN-lesioned rats than sham-operated rats, indicating that PVN lesions enhanced the orexigenic effects of ghrelin.

CONCLUSION

These results suggest that the hyperphagia and obesity induced by PVN lesions may be related to an increased orexigenic action of ghrelin, but not NPY.

Mechanism of microtubule array expansion in the cytokinetic phragmoplast

In land plants, the cell plate partitions the daughter cells at cytokinesis. The cell plate initially forms between daughter nuclei and expands centrifugally until reaching the plasma membrane. The centrifugal development of the cell plate is driven by the centrifugal expansion of the phragmoplast microtubule array, but the molecular mechanism underlying this expansion is unknown. Here, we show that the phragmoplast array comprises stable microtubule bundles and dynamic microtubules. We find that the dynamic microtubules are nucleated by γ-tubulin on stable bundles. The dynamic microtubules elongate at the plus ends and form new bundles preferentially at the leading edge of the phragmoplast. At the same time, they are moved away from the cell plate, maintaining a restricted distribution of minus ends. We propose that cycles of attachment of γ-tubulin complexes onto the microtubule bundles, microtubule nucleation and bundling, accompanied by minus-end-directed motility, drive the centrifugal development of the phragmoplast.

Enhancement of thermal damage in murine tumors by hydralazine-induced modification of blood flow and oxygen tension

We investigated changes in blood flow in normal muscle and in SCC-VII tumors treated by hyperthermia combined with hydralazine, to evaluate the enhancement of thermal tumor damage by hydralazine. We studied SCC-VII tumor-bearing C3H/He mice. Hydralazine was administered by intraperitoneal injection, and tumors were heated by a water bath. We measured blood flow using the laser Doppler method, and oxygen tension using polarography. The response of tumors to therapy was assessed using a growth delay analysis. In tumors, blood flow and O-2 tension significantly decreased with increasing doses of hydralazine. Compared to tumors treated by hydralazine alone or by hyperthermia alone, tumor blood flow was significantly decreased in the group treated by hyperthermia with hydralazine. In tumors treated by hyperthermia with hydralazine, blood flow was significantly decreased with increasing Hyd doses, heat durations, and temperatures. In normal muscle, no decrease in blood flow was induced by hyperthermia, hydralazine, or their combination. In tumors treated by hyperthermia (43 degrees C, 20 min) with hydralazine, a maximum additional growth delay was observed. Our results suggest that a decrease in tumor blood flow caused by hydralazine plays an important role in enhancement of the hyperthermic antitumor effect.