Elevated cardiac tissue level of aldosterone and mineralocorticoid receptor in diastolic heart failure: Beneficial effects of mineralocorticoid receptor blocker

Cardiac aldosterone levels have not been evaluated in diastolic heart failure (DHF), and its roles in this type of heart failure remain unclear. This study aimed to detect cardiac aldosterone by use of a liquid chromatographic-mass spectrometric method and to assess the effects of mineralocorticoid receptor blockade on hypertensive DHF. Dahl salt-sensitive rats fed 8% NaCl diet from 7 wk (hypertensive DHF model) were divided at 13 wk into three groups: those treated with subdepressor doses of eplerenone (12.5 or 40 mg x kg(-1) x day(-1)) and an untreated group. Dahl salt-sensitive rats fed 0.3% NaCl diet served as controls. Cardiac aldosterone was detected in the DHF rats but not in the control rats, with increased ventricular levels of mineralocorticoid receptor. Cardiac levels of 11-deoxycorticosterone, corticosterone, and 11-dehydrocorticosterone were not different between the control and DHF rats, but the tissue level of corticosterone that has an affinity to mineralocorticoid receptor was 1,000 times as high as that of aldosterone. Aldosterone synthase activity and CYP11B2 mRNA were undetectable in the ventricular tissue of the DHF rats. Administration of eplerenone attenuated ventricular hypertrophy, ventricular fibrosis, myocardial stiffening, and relaxation abnormality, leading to the prevention of overt DHF. In summary, the myocardial aldosterone level increased in the DHF rats. However, its value was extremely low compared with corticosterone, and no evidence for enhancement of intrinsic myocardial aldosterone production was found. The upregulation of mineralocorticoid receptor may play a central role in the pathogenesis of DHF, and blockade of mineralocorticoid receptor is likely an effective therapeutic regimen of DHF.     

Alteration of the neuronal and glial cell profiles in Neu1-deficient zebrafish

Glycoconjugate Journal - Neu1 is a glycosidase that releases sialic acids from the non-reducing ends of glycoconjugates, and its enzymatic properties are conserved among vertebrates. Recently,...     

Small Liposomes Accelerate the Fibrillation of Amyloid β (1–40)

The deposition of amyloid β (Aβ) peptides is a pathological hallmark of Alzheimer disease. Aβ peptides were previously considered to interact specifically with ganglioside-containing membranes. Several studies have suggested that Aβ peptides also bind to phosphatidylcholine membranes, which lead to deformation of membranes and fibrillation of Aβ. Moreover, the role of membrane curvature, one type of deformation produced by binding of proteins to a membrane, in the binding and fibrillation of Aβ remains unclear. To clearly understand the relationship between the binding, consequent membrane deformation, and fibrillation of Aβ, we examined the amyloid fibrillation of Aβ-(1–40) in the presence of liposomes of various sizes. Membrane curvature increased with a decrease in the size of the liposomes. We used liposomes made of 1,2-dioleoyl-sn-glycero-3-phosphocholine to eliminate electrostatic effects. The results obtained showed that liposomes of smaller sizes (≤50 nm) significantly accelerated the nucleation step, thereby shortening the lag time of fibrillation. On the other hand, liposomes of larger sizes decreased the amount of fibrils but did not notably affect the lag time. The morphologies of fibrils, which were monitored by total internal reflection fluorescence microscopy, atomic force microscopy, and transmission electron microscopy, revealed that the length of Aβ-(1–40) fibrils became shorter and the amount of amorphous aggregates became larger as liposomes increased in size. These results suggest that the curvature of membranes coupled with an increase in water-accessible hydrophobic regions is important for binding and concentrating Aβ monomers, leading to amyloid nucleation. Furthermore, amyloid fibrillation on membranes may compete with non-productive binding to produce amorphous aggregates.     

The Vitamin D Analogue ED71 but Not 1,25(OH)2D3 Targets HIF1α Protein in Osteoclasts

Although both an active form of the vitamin D metabolite, 1,25(OH)₂D₃, and the vitamin D analogue, ED71 have been used to treat osteoporosis, anti-bone resorbing activity is reportedly seen only in ED71- but not in 1,25(OH)₂D₃ -treated patients. In addition, how ED71 inhibits osteoclast activity in patients has not been fully characterized. Recently, HIF1α expression in osteoclasts was demonstrated to be required for development of post-menopausal osteoporosis. Here we show that ED71 but not 1,25(OH)₂D₃, suppress HIF1α protein expression in osteoclasts in vitro. We found that 1,25(OH)₂D₃ or ED71 function in osteoclasts requires the vitamin D receptor (VDR). ED71 was significantly less effective in inhibiting M-CSF and RANKL-stimulated osteoclastogenesis than was 1,25(OH)₂D₃ in vitro. Downregulation of c-Fos protein and induction of Ifnβ mRNA in osteoclasts, both of which reportedly block osteoclastogenesis induced by 1,25(OH)₂D₃ in vitro, were both significantly higher following treatment with 1,25(OH)₂D₃ than with ED71. Thus, suppression of HIF1α protein activity in osteoclasts in vitro, which is more efficiently achieved by ED71 rather than by 1,25(OH)₂D₃, could be a reliable read-out in either developing or screening reagents targeting osteoporosis.     

A novel sesquiterpenoid dimer parviflorene F induces apoptosis by up-regulating the expression of TRAIL-R2 and a caspase-dependent mechanism

Parviflorene F (1), a novel sesquiterpenoid dimer isolated from Curcuma parviflora Wall, is a cytotoxic compound. In this study, we examined the mechanism of its cytotoxic effect in HeLa cells. Treatment with 1 enhanced the mRNA and protein expression of TRAIL-R2 (tumor necrosis factor alpha-related apoptosis inducing ligand receptor 2). Apoptosis was induced by 1 as revealed by the distribution of DNA and Annexin V/PI staining using flow cytometry. In addition, 1-induced apoptosis was inhibited by human recombinant TRAIL-R2/Fc chimera protein, TRAIL-neutralizing fusion protein. Also, we found that 1 induced the activation of caspase-8, caspase-9, and caspase-3, indicating that the cytotoxic effect of 1 is correlated with apoptosis by a caspase-dependent mechanism through TRAIL-R2. In addition, 1 enhanced TRAIL-induced cell death against HeLa and TRAIL-resistant DLD1 cells. Taken together, up-regulation of TRAIL-R2 by 1 may contribute to sensitization of TRAIL-induced cell death.     

Sequence of 3,687 nucleotides from the 3' end of Sendai virus genome RNA and the predicted amino acid sequences of viral NP, P and C proteins.

The sequence of 3,687 nucleotides from the 3' end of the Sendai virus genome (Z strain) was determined by a molecular cloning technique followed by rapid sequence analysis. Two large open reading frames, one consisting of 1,572 nucleotides and the other of 1,704 nucleotides, were observed in the region, that is OP-1 and OP-2 from the 3' end of the genome. The amino acid sequences of the gene products were predicted from the observed sequence. Determination of amino acid compositions of viral proteins, P, HN, Fo, NP and M, led us to conclude that NP and P are the gene products of OP-1 and OP-2, respectively. An additional open reading frame consisting of 612 nucleotides (OP-3) was discovered in the 3' most proximal region of OP-2. The predicted product of OP-3 was considered to be viral non-structural protein C. The leader sequence of 51 nucleotides at the 3' terminal of the genome and consensus sequences at 3' and 5' ends of each gene for proteins NP and P were identified.     

Involvement of ERK Phosphorylation of Trigeminal Spinal Subnucleus Caudalis Neurons in Thermal Hypersensitivity in Rats with Infraorbital Nerve Injury

To evaluate the involvement of the mitogen-activated protein kinase (MAPK) cascade in orofacial neuropathic pain mechanisms, this study assessed nocifensive behavior evoked by mechanical or thermal stimulation of the whisker pad skin, phosphorylation of extracellular signal-regulated kinase (ERK) in trigeminal spinal subnucleus caudalis (Vc) neurons, and Vc neuronal responses to mechanical or thermal stimulation of the whisker pad skin in rats with the chronic constriction nerve injury of the infraorbital nerve (ION-CCI). The mechanical and thermal nocifensive behavior was significantly enhanced on the side ipsilateral to the ION-CCI compared to the contralateral whisker pad or sham rats. ION-CCI rats had an increased number of phosphorylated ERK immunoreactive (pERK-IR) cells which also manifested NeuN-IR but not GFAP-IR and Iba1-IR, and were significantly more in ION-CCI rats compared with sham rats following noxious but not non-noxious mechanical stimulation. After intrathecal administration of the MEK1 inhibitor PD98059 in ION-CCI rats, the number of pERK-IR cells after noxious stimulation and the enhanced thermal nocifensive behavior but not the mechanical nocifensive behavior were significantly reduced in ION-CCI rats. The enhanced background activities, afterdischarges and responses of wide dynamic range neurons to noxious mechanical and thermal stimulation in ION-CCI rats were significantly depressed following i.t. administration of PD98059, whereas responses to non-noxious mechanical and thermal stimulation were not altered. The present findings suggest that pERK-IR neurons in the Vc play a pivotal role in the development of thermal hypersensitivity in the face following trigeminal nerve injury.     

Isolation and characterization of temperature-sensitive mutants of Sendai virus

Sixteen temperature-sensitive mutants of Sendai virus were isolated from mutagenized stocks (10 mutants, designated numerically) and persistently infected cultures (6 mutants, designated alphabetically). Based on complementation tests, virion-associated activities, thermal inactivation, and viral RNA and hemadsorbing antigen synthesis as well as virion production in chick lung embryo cells at nonpermissive temperature, these mutants were divided into seven groups as follows. i) HANA group mutants (ts-5, -9, -10, -201), defective in hemagglutinin-neuraminidase protein, complementation group I. ii) F group mutants (ts-18, -108), defective in hemolytic and cell-fusing activity, complementation group II. iii) Ts-43, defective in RNA polymerase activity, complementation group III. iv) Ts-23, defective in RNA polymerase activity, interfered with the other mutants in complementation tests. v) Ts-25, defective in the incorporation of hemagglutinin-neuraminidase protein into the virion at the stage of virus assembly. vi) Ts-110, belongs to F group mutants on one hand, but is considered to carry another undetermined defect. vii) C group (carrier culture-borne group) mutants (ts-a, -b, -c, -d, -e, -f), defective lesion not yet determined and belong to neither complementation group I nor II. Assignment of mutants in groups iv), v), vi), and vii) to complementation groups could not be achieved.