The delta-opioid receptor agonist DADLE at reperfusion protects the heart through activation of pro-survival kinases via EGF receptor transactivation

The specific delta-opioid receptor agonist [D-Ala(2)-D-Leu(5)]enkephalin (DADLE) protects against infarction in the heart when given before ischemia. In rabbit, this protection leads to phosphorylation of the pro-survival kinases Akt and extracellular signal-regulated kinase (ERK) and is dependent on transactivation of the epidermal growth factor receptor (EGFR). DADLE reportedly protects rat hearts at reperfusion. We therefore tested whether DADLE at reperfusion could protect isolated rabbit hearts subjected to 30 min of regional ischemia and 120 min of reperfusion and whether this protection is dependent on Akt, ERK, and EGFR. DADLE (40 nM) was infused for 1 h starting 5 min before reperfusion and reduced infarct size from 31.0 +/- 2.3% in the control group to 14.6 +/- 1.6% (P = 0.01). This protection was abolished by cotreatment of the metalloproteinase inhibitor (MPI) and the EGFR inhibitor AG1478. In contrast, 20 nM DADLE, although known to be protective before ischemia, failed to protect. Western blotting revealed that DADLE's protection was correlated to increase in phosphorylation of the kinases Akt and ERK1 and -2 in reperfused hearts (2.5 +/- 0.5, 1.6 +/- 0.2, and 2.3 +/- 0.7-fold of baseline levels, P < 0.05 vs. control). The DADLE-dependent increases in Akt and ERK1/2 phosphorylation were abolished by either MPI or AG1478, confirming a signaling through the EGFR pathway. Additionally, DADLE treatment increased phosphorylation of EGFR (1.4 +/- 0.2-fold, P = 0.03 vs. control). Thus the delta-opioid agonist DADLE protects rabbit hearts at reperfusion through activation of the pro-survival kinases Akt and ERK and is dependent on the transactivation of the EGFR.     

Thigh muscle activation distribution and pulmonary VO2 kinetics during moderate, heavy, and very heavy intensity cycling exercise in humans

The mechanisms underlying the oxygen uptake (Vo(2)) slow component during supra-lactate threshold (supra-LT) exercise are poorly understood. Evidence suggests that the Vo(2) slow component may be caused by progressive muscle recruitment during exercise. We therefore examined whether leg muscle activation patterns [from the transverse relaxation time (T2) of magnetic resonance images] were associated with supra-LT Vo(2) kinetic parameters. Eleven subjects performed 6-min cycle ergometry at moderate (80% LT), heavy (70% between LT and critical power; CP), and very heavy (7% above CP) intensities with breath-by-breath pulmonary Vo(2) measurement. T2 in 10 leg muscles was evaluated at rest and after 3 and 6 min of exercise. During moderate exercise, nine muscles achieved a steady-state T2 by 3 min; only in the vastus medialis did T2 increase further after 6 min. During heavy exercise, T2 in the entire vastus group increased between minutes 3 and 6, and additional increases in T2 were seen in adductor magnus and gracilis during this period of very heavy exercise. The Vo(2) slow component increased with increasing exercise intensity (being functionally zero during moderate exercise). The distribution of T2 was more diverse as supra-LT exercise progressed: T2 variance (ms) increased from 3.6 +/- 0.2 to 6.5 +/- 1.7 between 3 and 6 min of heavy exercise and from 5.5 +/- 0.8 to 12.3 +/- 5.4 in very heavy exercise (rest = 3.1 +/- 0.6). The T2 distribution was significantly correlated with the magnitude of the Vo(2) slow component (P < 0.05). These data are consistent with the notion that the Vo(2) slow component is an expression of progressive muscle recruitment during supra-LT exercise.     

Coprinellus curtus (Hitoyo-take) prevents diseases of vegetables caused by pathogenic fungi

A strain of Coprinellus curtus (designated GM-21), a basidiomycete that suppressed bottom-rot disease of Chinese cabbage, 'pak-choi' (Brassica campestris), caused by the pathogen Rhizoctonia solani Pak-choi 2 was isolated. The mechanism of plant disease suppression was discovered to be hyphal interference, a combative fungal interaction between strain GM-21 and the pathogen. The antifungal spectrum of strain GM-21 was shown to include R. solani and Fusarium sp., i.e. strain GM-21 showed disease-suppressive ability against bottom-rot disease of lettuce and Rhizoctonia-patch disease of mascarene grass caused by strains of R. solani. In addition, clear evidence of hyphal interference between strain GM-21 and Fusarium pathogens that cause crown (foot) and root-rot disease of tomato and Fusarium wilt of melon, respectively, was demonstrated. It was thus considered that GM-21 is effective for suppressing soil-borne pathogens, and that GM-21 presents new possibilities for biological control of vegetable diseases.     

MyrSINEs: a novel SINE family in the anteater genomes

Recent rapid generation of genomic sequence data has allowed many researchers to perform comparative analyses in various mammalian species. However, characterization of transposable elements, such as short interspersed repetitive elements (SINEs), has not been reported for several mammalian groups. Because SINEs occupy a large portion of the mammalian genome, they are believed to have contributed to the constitution and diversification of the host genomes during evolution. In the present study, we characterized a novel SINE family in the anteater genomes and designated it the MyrSINE family. Typical SINEs consist of a tRNA-related, a tRNA-unrelated and an AT-rich (or poly-A) region. MyrSINEs have only tRNA-related and poly-A regions; they are included in a group called t-SINE. The tRNA-related regions of the MyrSINEs were found to be derived from tRNA^Gly. We demonstrate that the MyrSINE family can be classified into three subfamilies. Two of the MyrSINE subfamilies are distributed in the genomes of both giant anteater and tamandua, while the other is present only in the giant anteater. We discuss the evolutionary history of MyrSINEs and their relationship to the evolution of anteaters. We also speculate that the simple structure of t-SINEs may be a potential evolutionary source for the generation of the typical SINE structure.     

A novel strategy for mammalian cell surface glycome profiling using lectin microarray

The glycome represents the total set of glycans expressed in a cell. The glycome has been assumed to vary between cell types, stages of development and differentiation, and during malignant transformation. Analysis of the glycome provides a basis for understanding the functions of glycans in these cellular processes. Recently, a technique called lectin microarray was developed for rapid profiling of glycosylation, although its use was mainly restricted to glycoproteins of cell lysates, and thus unable to profile the intact cell surface glycans. Here we report a simple and sensitive procedure based on this technology for direct analysis of the live mammalian cell-surface glycome. Fluorescent-labeled live cells were applied in situ to the established lectin microarray consisting of 43 immobilized lectins with distinctive binding specificities. After washing, bound cells were directly detected by an evanescent-field fluorescence scanner in a liquid phase without fixing and permeabilization. The results obtained by differential profiling of CHO and its glycosylation-defective mutant cells, and splenocytes of wild-type and beta1-3-N-acetylglucosaminyltransferase II knockout mice performed as model experiments agreed well with their glycosylation phenotypes. We also compared cell surface glycans of K562 cells before and after differentiation and found a significant increase in the expression of O-glycans on differentiated cells. These results demonstrate that the technique provides a novel strategy for profiling global changes of the mammalian cell surface glycome.     

Molecular mechanisms and physiological functions of mitophagy

Degradation of mitochondria via a selective form of autophagy, named mitophagy, is a fundamental mechanism conserved from yeast to humans that regulates mitochondrial quality and quantity control. Mitophagy is promoted via specific mitochondrial outer membrane receptors, or ubiquitin molecules conjugated to proteins on the mitochondrial surface leading to the formation of autophagosomes surrounding mitochondria. Mitophagy‐mediated elimination of mitochondria plays an important role in many processes including early embryonic development, cell differentiation, inflammation, and apoptosis. Recent advances in analyzing mitophagy in vivo also reveal high rates of steady‐state mitochondrial turnover in diverse cell types, highlighting the intracellular housekeeping role of mitophagy. Defects in mitophagy are associated with various pathological conditions such as neurodegeneration, heart failure, cancer, and aging, further underscoring the biological relevance. Here, we review our current molecular understanding of mitophagy, and its physiological implications, and discuss how multiple mitophagy pathways coordinately modulate mitochondrial fitness and populations.     

A Combretastatin-Mediated Decrease in Neutrophil Concentration in Peripheral Blood and the Impact on the Anti-Tumor Activity of This Drug in Two Different Murine Tumor Models

The vascular disrupting agent combretastatin A-4 disodium phosphate (CA4P) induces fluctuations in peripheral blood neutrophil concentration. Because neutrophils have the potential to induce both vascular damage and angiogenesis we analyzed neutrophil involvement in the anti-tumoral effects of CA4P in C3H mammary carcinomas in CDF1 mice and in SCCVII squamous cell carcinomas in C3H/HeN mice. Flow cytometry analyses of peripheral blood before and up to 144 h after CA4P administration (25 and 250 mg/kg) revealed a decrease 1 h after treatment, followed by an early (3–6 h) and a late (>72 h) increase in the granulocyte concentration. We suggest that the early increase (3–6 h) in granulocyte concentration was caused by the initial decrease at 1 h and found that the late increase was associated with tumor size, and hence independent of CA4P. No alterations in neutrophil infiltration into the C3H tumor after CA4P treatment (25 and 250 mg/kg) were found. Correspondingly, neutrophil depletion in vivo, using an anti-neutrophil antibody, followed by CA4P treatment (25 mg/kg) did not increase the necrotic fraction in C3H tumors significantly. However, by increasing the CA4P dose to 250 mg/kg we found a significant increase of 359% in necrotic fraction when compared to neutrophil-depleted mice; in mice with no neutrophil depletion CA4P induced an 89% change indicating that the presence of neutrophils reduced the effect of CA4P. In contrast, neither CA4P nor 1A8 affected the necrotic fraction in the SCCVII tumors significantly. Hence, we suggest that the initial decrease in granulocyte concentration was caused by non-tumor-specific recruitment of neutrophils and that neutrophils may attenuate CA4P-mediated anti-tumor effect in some tumor models.