Matrine modulates HSC70 levels and rescues ΔF508-CFTR

Cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-dependent Cl(-) channel located in the plasma membrane, and its malfunction results in cystic fibrosis (CF), the most common lethal genetic disease in Caucasians. Most CF patients carry the deletion of Phe508 (ΔF508 mutation); this mutation prevents the delivery of the CFTR to its correct cellular location, the apical (lumen-facing) membrane of epithelial cells. Molecular chaperones play a central role in determining the fate of ΔF508-CFTR. In this report, we show that the Matrine, a quinolizidine alkaloid, downregulates the expression of the molecular chaperone HSC70 and increases the protein levels of ΔF508-CFTR in human alveolar basal epithelial cells (A549 cell line), stably transfected with a ΔF508-CFTR-expressing construct. Moreover, Matrine induced ΔF508-CFTR release from endoplasmic reticulum to cell cytosol and its localization on the cell membrane. Interestingly, downregulation of HSC70 resulted in increased levels of ΔF508-CFTR complexes with the co-chaperone BAG3 that in addition appeared to co-localize with the mutated protein on the cell surface. These results shed new light on ΔF508-CFTR interactions with proteins of the chaperones/co-chaperones system and could be useful in strategies for future medical treatments for CF.     

Validation of a novel index to assess insulin resistance of adipose tissue lipolytic activity in obese subjects

Insulin resistance in adipose tissue increases the release of free fatty acids into the circulation, which likely contributes to impaired insulin action in liver and skeletal muscle associated with obesity. However, reliable assessment of adipose tissue insulin resistance requires performing a hyperinsulinemic-euglycemic clamp procedure in conjunction with a fatty acid tracer infusion to determine insulin-mediated suppression of lipolytic rate. We developed a simpler method for evaluating adipose tissue insulin resistance in vivo, determined as the product of palmitate rate of appearance into the bloodstream and plasma insulin concentration during basal conditions. We validated our Adipose Tissue Insulin Resistance Index (ATIRI) by comparison with an assessment of adipose tissue insulin resistance determined by using the hyperinsulinemic-euglycemic clamp procedure in conjunction with a palmitate tracer infusion in 47 obese nondiabetic subjects (body mass index: 40.1 ± 9.3 kg/m(2)). We found the ATIRI correlated closely with adipose tissue insulin resistance assessed during the clamp procedure (r =-0.854, P < 0.001). These results demonstrate that the ATIRI provides a reliable index of adipose tissue insulin resistance in obese subjects.     

Ceramide 1-phosphate stimulates proliferation of C2C12 myoblasts

Recent studies have established specific cellular functions for different bioactive sphingolipids in skeletal muscle cells. Ceramide 1-phosphate (C1P) is an important bioactive sphingolipid that has been involved in cell growth and survival. However its possible role in the regulation of muscle cell homeostasis has not been so far investigated. In this study, we show that C1P stimulates myoblast proliferation, as determined by measuring the incorporation of tritiated thymidine into DNA, and progression of the myoblasts through the cell cycle. C1P induced phosphorylation of glycogen synthase kinase-3β and the product of retinoblastoma gene, and enhanced cyclin D1 protein levels. The mitogenic action of C1P also involved activation of phosphatidylinositol 3-kinase/Akt, ERK1/2 and the mammalian target of rapamycin. These effects of C1P were independent of interaction with a putative G(i)-coupled C1P receptor as pertussis toxin, which maintains G(i) protein in the inactive form, did not affect C1P-stimulated myoblast proliferation. By contrast, C1P was unable to inhibit serum starvation- or staurosporine-induced apoptosis in the myoblasts, and did not affect myogenic differentiation. Collectively, these results add up to the current knowledge on cell types targeted by C1P, which so far has been mainly confined to fibroblasts and macrophages, and extend on the mechanisms by which C1P exerts its mitogenic effects. Moreover, the biological activities of C1P described in this report establish that this phosphosphingolipid may be a relevant cue in the regulation of skeletal muscle regeneration, and that C1P-metabolizing enzymes might be important targets for developing cellular therapies for treatment of skeletal muscle degenerative diseases, or tissue injury.     

A peculiar mutation in the DNA-binding/dimerization domain of NFIX causes Sotos-like overgrowth syndrome: A new case

The Nuclear Factor I-X (NFIX) is a member of the nuclear factor I (NFI) family proteins, which are implicated as site-specific DNA-binding proteins and is deleted or mutated in a subset of patients with Sotos-like overgrowth syndrome and in patients with Marshall–Smith syndrome. We evaluated an additional patient with clinical features of Sotos-like syndrome by sequencing analysis of the NFIX gene and identified a 21 nucleotide in frame deletion predicting loss of 7 amino acids in the DNA-binding/dimerization domain of the NFIX protein. The deleted residues are all evolutionally conserved amino acids. The present report further confirms that mutations in DNA-binding/dimerization domain cause haploinsufficiency of the NFIX protein and strongly suggests that in individuals with Sotos-like features unrelated to NSD1 changes genetic testing of NFIX should be considered.     

Genome Sequence of “Candidatus Microthrix parvicella” Bio17-1, a Long-Chain-Fatty-Acid-Accumulating Filamentous Actinobacterium from a Biological Wastewater Treatment Plant

“Candidatus Microthrix” bacteria are deeply branching filamentous actinobacteria which occur at the water-air interface of biological wastewater treatment plants, where they are often responsible for foaming and bulking. Here, we report the first draft genome sequence of a strain from this genus: “Candidatus Microthrix parvicella” strain Bio17-1.     

A novel series of benzimidazole NR2B-selective NMDA receptor antagonists

A series of novel benzimidazoles are discussed as NR2B-selective N-methyl-d-aspartate (NMDA) receptor antagonists. High throughput screening (HTS) efforts identified a number of potent and selective NR2B antagonists such as 1. Exploration of the substituents around the core of this template identified a number of compounds with high potency for NR2B (pIC(50) >7) and good selectivity against the NR2A subunit (pIC(50) <4.3) as defined by FLIPR-Ca(2+) and radioligand binding studies. These agents offer potential for the development of therapeutics for a range of nervous system disorders including chronic pain, neurodegeneration, migraine and major depression.     

Effect of eplerenone on parathyroid hormone levels in patients with primary hyperparathyroidism: a randomized, double-blind, placebo-controlled trial

ABSTRACT: BACKGROUND: Increasing evidence suggests the bidirectional interplay between parathyroid hormone and aldosterone as an important mechanism behind the increased risk of cardiovascular damage and bone disease observed in primary hyperparathyroidism. Our primary object is to assess the efficacy of the mineralocorticoid receptor-blocker eplerenone to reduce parathyroid hormone secretion in patients with parathyroid hormone excess. Methods/design Overall, 110 adult male and female patients with primary hyperparathyroidism will be randomly assigned to eplerenone (25 mg once daily for 4 weeks and 4 weeks with 50 mg once daily after dose titration] or placebo, over eight weeks. Each participant will undergo detailed clinical assessment, including anthropometric evaluation, 24-h ambulatory arterial blood pressure monitoring, echocardiography, kidney function and detailed laboratory determination of biomarkers of bone metabolism and cardiovascular disease. The study comprises the following exploratory endpoints: mean change from baseline to week eight in (1) parathyroid hormone(1--84) as the primary endpoint and (2) 24-hour systolic and diastolic ambulatory blood pressure levels, NT-pro-BNP, biomarkers of bone metabolism, 24 hours urinary protein/albumin excretion and echocardiographic parameters reflecting systolic and diastolic function as well as cardiac dimensions, as secondary endpoints. DISCUSSION: In view of the reciprocal interaction between aldosterone and parathyroid hormone and the potentially ensuing target organ damage, the EPATH trial is designed to determine whether eplerenone, compared to placebo, will effectively impact on parathyroid hormone secretion and improve cardiovascular and bone health in patients with primary hyperparathyroidism. Trial registration ISRCTN33941607.     

Nanomolar melatonin enhances nNOS expression and controls HaCaT-cells bioenergetics

A novel role of melatonin was unveiled, using immortalized human keratinocyte cells (HaCaT) as a model system. Within a time window compatible with its circadian rhythm, melatonin at nanomolar concentration raised both the expression level of the neuronal nitric oxide synthase mRNA and the nitric oxide oxidation products, nitrite and nitrate. On the same time scale, a depression of the mitochondrial membrane potential was detected together with a decrease of the oxidative phosphorylation efficiency, compensated by glycolysis as testified by an increased production of lactate. The melatonin concentration, ～ nmolar, inducing the bioenergetic effects and their time dependence, both suggest that the observed nitric oxide-induced mitochondrial changes might play a role in the metabolic pathways characterizing the circadian melatonin chemistry.