Angiotensin-converting enzyme is a GPI-anchored protein releasing factor crucial for fertilization

The angiotensin-converting enzyme (ACE) is a key regulator of blood pressure. It is known to cleave small peptides, such as angiotensin I and bradykinin and changes their biological activities, leading to upregulation of blood pressure. Here we describe a new activity for ACE: a glycosylphosphatidylinositol (GPI)-anchored protein releasing activity (GPIase activity). Unlike its peptidase activity, GPIase activity is weakly inhibited by the tightly binding ACE inhibitor and not inactivated by substitutions of core amino acid residues for the peptidase activity, suggesting that the active site elements for GPIase differ from those for peptidase activity. ACE shed various GPI-anchored proteins from the cell surface, and the process was accelerated by the lipid raft disruptor filipin. The released products carried portions of the GPI anchor, indicating cleavage within the GPI moiety. Further analysis by high-performance liquid chromatography-mass spectrometry predicted the cleavage site at the mannose-mannose linkage. GPI-anchored proteins such as TESP5 and PH-20 were released from the sperm membrane of wild-type mice but not in Ace knockout sperm in vivo. Moreover, peptidase-inactivated E414D mutant ACE and also PI-PLC rescued the egg-binding deficiency of Ace knockout sperms, implying that ACE plays a crucial role in fertilization through this activity.     

Edaravone inhibits acute renal injury and cyst formation in cisplatin-treated rat kidney

Background: Although cis-diamminedichloroplatinum (II) (cisplatin) is an effective anticancer agent, its clinical use is highly limited predominantly due to its adverse effects on renal functions. The present work examined the therapeutic potential of edaravone, a free radical scavenger, for inhibiting cisplatin-induced renal injury.

Methods: Edaravone, 3-methyl-1-phenyl-pyrazolin-5-one, was administrated intravenously at a dose of 30 mg/kg of body weight to male Wistar rats (200-220 g). After 30 min, cisplatin was injected intraperitoneally at a dose of 5 mg/kg of body weight. At the indicated times after the treatment, functions and histological changes of the kidney were analyzed. To test the therapeutic potential of edaravone in chemotherapy, its effect on the anticancer action of cisplatin was examined in ascites cancer-bearing rats.

Results: We found that cisplatin rapidly impaired the respiratory function and DNA of mitochondria in renal proximal tubules, thereby inducing apoptosis of tubular epithelial cells within a few days and chronic renal dysfunction associated with multiple cysts one-year after the administration. Administration of edaravone inhibited the cisplatin-induced acute injury of mitochondria and their DNA and renal epithelial cell apoptosis as well as the occurrence of chronic renal dysfunction and multiple cyst formation. The anticancer effect of cisplatin remained unaffected by intravenous administrating of edaravone.

Conclusions: These results indicate that edaravone may have therapeutic potential for inhibiting the acute and chronic injury of the kidney induced by cisplatin.     

Temperature requirements for growth and maturation of the warm temperate kelp Eckloniopsis radicosa (Laminariales,Phaeophyta)

The annual kelp Eckloniopsis radicosa is distributed along Japanese coasts and occurs within the area with a February isotherm ranging 15–18°C and August isotherm ranging 25–28°C. In this study, the effects of temperature on the gametophyte growth and maturation, and the young sporophyte growth of E. radicosa were examined and the results are discussed in relation to the distribution of other warm‐adapted kelp species and the potential effects of climate change. The optimal temperature ranges for growth of male and female gametophytes were 23–27°C and 20–26°C, respectively. The upper survival temperature for gametophyte growth was 31°C for males and 30°C for females, respectively. The optimal temperature range for maturation of female gametophytes was ≤23°C. The optimal temperature range for growth of young sporophytes was 14–22°C. It was clarified that E. radicosa has the most warm‐adapted characteristics for growth and maturation of gametophytes among members of the Laminariales studied so far. The natural seawater temperature ranges during the growth and maturation seasons for gametophytes of E. radicosa, as well as the growth season for young sporophytes near to the northern and southern distribution limits (Izu‐Oshima: 14.9–24.5°C, Ichiki‐kushikino: 17.1–29.6°C), agreed with the experimentally determined temperature requirements. The warm‐adapted gametophyte stage and annual lifecycle are major factors enabling survival of E. radicosa in warm waters near tropical regions along the Japanese coast.     

Phosphorus magnetic resonance spectroscopy 2 h after perinatal cerebral hypoxia-ischemia prognosticates outcome in the newborn piglet

Phosphorus magnetic resonance spectroscopy ((31)P MRS) often reveals apparently normal brain metabolism in the first hours after intrapartum hypoxia-ischemia (HI) at a time when conventional clinical assessment of injury severity is problematic. We aimed to elucidate very-early, injury-severity biomarkers. Twenty-seven newborn piglets underwent cerebral HI: (31)P-MRS measures approximately 2 h after HI were compared between injury groups defined by secondary-energy-failure severity as quantified by the minimum nucleotide triphosphate (NTP) observed after 6 h. For severe and moderate injury versus baseline, [Pi]/[total exchangeable high-energy phosphate pool (EPP)] was increased (p < 0.001 and < 0.02, respectively), and [NTP]/[EPP] decreased (p < 0.03 and < 0.006, respectively): severe-injury [Pi]/[EPP] was also increased versus mild injury (p < 0.04). Mild-injury [phosphocreatine]/[EPP] was increased (p < 0.004). Severe-injury intracellular pH was alkaline versus baseline (p < 0.002). For severe and moderate injury [total Mg]/[ATP] (p < 0.0002 and < 0.02, respectively) and [free Mg] (p < 0.0001 and < 0.02, respectively) were increased versus baseline. [Pi]/[EPP], [phosphocreatine]/[Pi] and [NTP]/[EPP] correlated linearly with injury severity (p < 0.005, < 0.005 and < 0.02, respectively). Increased [Pi]/[EPP], intracellular pH and intracellular Mg approximately 2 h after intrapartum HI may prognosticate severe injury, whereas increased [phosphocreatine]/[EPP] may suggest mild damage. In vivo(31)P MRS may have potential to provide very-early prognosis in neonatal encephalopathy.     

Enhanced insulin sensitivity, energy expenditure and thermogenesis in adipose-specific Pten suppression in mice

Pten is an important phosphatase, suppressing the phosphatidylinositol-3 kinase/Akt pathway. Here, we generated adipose-specific Pten-deficient (AdipoPten-KO) mice, using newly generated Acdc promoter-driven Cre transgenic mice. AdipoPten-KO mice showed lower body and adipose tissue weights despite hyperphagia and enhanced insulin sensitivity with induced phosphorylation of Akt in adipose tissue. AdipoPten-KO mice also showed marked hyperthermia and increased energy expenditure with induced mitochondriagenesis in adipose tissue, associated with marked reduction of p53, inactivation of Rb, phosphorylation of cyclic AMP response element binding protein (CREB) and increased expression of Ppargc1a, the gene that encodes peroxisome proliferative activated receptor gamma coactivator 1 alpha. Physiologically, adipose Pten mRNA decreased with exposure to cold and increased with obesity, which were linked to the mRNA alterations of mitochondriagenesis. Our results suggest that altered expression of adipose Pten could regulate insulin sensitivity and energy expenditure. Suppression of adipose Pten may become a beneficial strategy to treat type 2 diabetes and obesity.     

Studies on Plant Growth Substances

The plant growth activities of the dihydro- and tetrahydro-1-naphthoic acids substituted with a halogen, methyl or nitro group at various positions of the aromatic ring are measured by the pea straight-growth test. The relationship between structure and activity is discussed. The results seem to conform well with the spatial structure hypothesis of Veldstra.     

Methyl‐isobutyl amiloride reduces brain Lac/NAA,cell death and microglial activation in a perinatal asphyxia model

Na⁺/H⁺ exchanger (NHE) blockade attenuates the detrimental consequences of ischaemia and reperfusion in myocardium and brain in adult and neonatal animal studies. Our aim was to use magnetic resonance spectroscopy (MRS) biomarkers and immunohistochemistry to investigate the cerebral effects of the NHE inhibitor, methyl isobutyl amiloride (MIA) given after severe perinatal asphyxia in the piglet. Eighteen male piglets (aged < 24 h) underwent transient global cerebral hypoxia‐ischaemia and were randomized to (i) saline placebo; or (ii) 3 mg/kg intravenous MIA administered 10 min post‐insult and 8 hourly thereafter. Serial phosphorus‐31 (³¹P) and proton (¹H) MRS data were acquired before, during and up to 48 h after hypoxia‐ischaemia and metabolite‐ratio time‐series Area under the Curve (AUC) calculated. At 48 h, histological and immunohistochemical assessments quantified regional tissue injury. MIA decreased thalamic lactate/N‐acetylaspartate and lactate/creatine AUCs (both p < 0.05) compared with placebo. Correlating with improved cerebral energy metabolism, transferase mediated biotinylated d‐UTP nick end‐labelling (TUNEL) positive cell density was reduced in the MIA group in cerebral cortex, thalamus and white matter (all p < 0.05) and caspase 3 immunoreactive cells were reduced in pyriform cortex and caudate nucleus (both p < 0.05). Microglial activation was reduced in pyriform and midtemporal cortex (both p < 0.05). Treatment with MIA starting 10 min after hypoxia‐ischaemia was neuroprotective in this perinatal asphyxia model.     

The conjugation of RGDS peptide with CM-chitin augments the peptide-mediated inhibition of tumor metastasis

A water soluble 6-O-carboxymethyl chitin (CM-chitin) containing cell adhesive Arg-Gly-Asp-Ser (RGDS) sequence, i.e. CM-chitin-RGDS conjugate was synthesized, and the inhibitory effects of this compound on lung or liver metastasis of lung-metastatic B16-BL6 melanoma or liver-metastatic L5178Y-ML25 lymphoma cells in mice was examined. CM-chitin-RGDS showed the inhibitory effects on lung metastasis of melanoma cells in a dose-dependent manner (ranging from 100 to 1000 μg) and on liver metastasis of lymphoma cells. A mixture of CM-chitin and RGDS peptide or CM-chitin alone did not show any inhibitory effect on experimental lung metastasis as compared with the conjugate CM-chitin-RGDS on a molar basis. GRGDS peptide, however, required a higher dose (3000 μg) to obtain a sufficiently antimetastatic effect. The in-vitro tumor invasion study showed that CM-chitin-RGDS was apparently more effective for the inhibition of tumor cell penetration into reconstituted basement membrane Matrigel than RGDS or the mixture of RGDS and CM-chitin on a molar basis. Intermittent i.v. administration of CM-chitin-RGDS after the inoculation of B16-BL6 cells caused significant inhibition of spontaneous lung metastasis produced by intrafootpad injection of tumor cells as compared with the multiple administration of RGDS, CM-chitin or untreated control. These results demonstrate the importance of the conjugation of RGDS peptide with CM-chitin as a polymeric carrier for the increased therapeutic potential to cancer metastasis, thus implying a possibility that RGDS-polymer conjugation may lead to the prolongation of antimetastatic action of RGDS peptide in vivo.