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.     

Effect of bovine lactoferrin in a therapeutic hamster model of hepatic amoebiasis

Entamoeba histolytica is the causative agent of amoebiasis, a disease that produces dysentery as a result of the perforation of the large intestine. This parasite often invades other organs, primarily the liver, leading to an amoebic liver abscess (ALA), which can cause death. Metronidazole is the drug of choice for the treatment of ALA; however, it produces toxic side effects in patients. Lactoferrin (Lf) is a glycoprotein of the innate immune response that sequesters iron in the mucosae. Lf possesses immune-regulatory properties, such as antiinflammatory and antioxidant activities. Moreover, the microbicidal activity of apoLf, which lacks bound iron, has been shown. In this study, we evaluated the therapeutic effect of bovine Lf (bLf) against ALA in a model of hepatic amoebiasis in hamsters. Interestingly, hamsters treated intragastrically with Lf (2.5 mg/100 g mass) over a period of 8 days showed no clinical signs of disease and ALA was effectively decreased, with only 0.63% detectable lesion, compared with 63% in untreated animals. Furthermore, liver function and blood cells approached normal levels among those receiving bLf treatment. These results suggest that bLf may aid in the therapy of amoebiasis, likely without producing undesirable effects in patients.     

Procyanidins can interact with Caco-2 cell membrane lipid rafts: Involvement of cholesterol

Large procyanidins (more than three subunits) are not absorbed at the gastrointestinal tract but could exert local effects through their interactions with membranes. We previously showed that hexameric procyanidins (Hex), although not entering cells, interact with membranes modulating cell signaling and fate. This paper investigated if Hex, as an example of large procyanidins, can selectively interact with lipid rafts which could in part explain its biological actions. This mechanism was studied in both synthetic membranes (liposomes) and Caco-2 cells. Hex promoted Caco-2 cell membrane rigidification and dehydration, effects that were abolished upon cholesterol depletion with methyl-β-cyclodextrin (MCD). Hex prevented lipid raft structure disruption induced by cholesterol depletion/redistribution by MCD or sodium deoxycholate. Supporting the involvement of cholesterol–Hex bonding in Hex interaction with lipid rafts, the absence of cholesterol markedly decreased the capacity of Hex to prevent deoxycholate- and Triton X-100-mediated disruption of lipid raft-like liposomes. Stressing the functional relevance of this interaction, Hex mitigated lipid raft-associated activation of the extracellular signal-regulated kinases (ERK) 1/2. Results support the capacity of a large procyanidin (Hex) to interact with membrane lipid rafts mainly through Hex–cholesterol bondings. Procyanidin–lipid raft interactions can in part explain the capacity of large procyanidins to modulate cell physiology.     

Arylesterase activity of paraoxonase 1 (PON1) on HDL3 and HDL2: Relationship with Q192R,C-108T,and L55M polymorphisms

BackgroundControversy exists regarding the role of the subfractions of high-density lipoproteins (HDL₂ and HDL₃) in cardiovascular disease. The functionality of these particles, and their protective role, is due in part to the paraoxonase 1 (PON1) presence in them. The polymorphisms rs662 (Q192R, A/G), rs854560 (L55 M, T/A), and rs705379 (C-108T) of the PON1 gene have been related to enzyme activity and, with the anti-oxidative capacity of the HDL. The objective was to determine the arylesterase PON1 activity in HDL₃ and HDL₂ and its relationship with the polymorphisms mentioned, in a young population.MethodsThe polymorphisms were determined through mini-sequencing (SnaPshot). The HDL subpopulations were separated via ionic precipitation, cholesterol was measured with enzymatic methods, and PON1 activity was measured through spectrophotometry.ResultsThe results show that the PON1 polymorphisms do not influence the cholesterol in the HDL. A variation between 40.02 and 43.9 mg/dL was in all the polymorphisms without significant differences. Additionally, PON1 activity in the HDL₃ subfractions was greater (62.83 ± 20 kU/L) than with HDL₂ (35.8 ± 20.8 kU/L) in the whole population and in all the polymorphisms (p < 0.001), and it was independent of the polymorphism and differential arylesterase activity in the Q192R polymorphism (QQ > QR > RR). Thus, 115.90 ± 30.7, 88.78 ± 21.3, 65.29 ± 10.2, respectively, for total HDL, with identical behavior for HDL₃ and HDL₂.ConclusionsPON1 polymorphisms do not influence the HDL_-c, and the PON activity is greater in the HDL₃ than in the HDL₂, independent of the polymorphism, but it is necessary to delve into the functionality of these findings in different populations.     

Clinico‐molecular analysis of eleven patients with Hermansky–Pudlak type 5 syndrome,a mild form of HPS

Hermansky–Pudlak syndrome (HPS), first described in 1959, is a rare form of syndromic oculocutaneous albinism associated with bleeding diathesis and in some cases pulmonary fibrosis and granulomatous colitis. All 10 HPS types are caused by defects in vesicle trafficking of lysosome‐related organelles (LRO) proteins. The HPS5 protein associates with HPS3 and HPS6 to form the biogenesis of lysosome‐related organelles complex‐2 (BLOC‐2). Here, we report the clinical and genetic data of 11 patients with HPS‐5 analyzed in our laboratory. We report 11 new pathogenic variants. The 11 patients present with ocular features that are typical for albinism, with mild hypopigmentation, and with no other major complication, apart from a tendency to bleed. HPS‐5 therefore appears as a mild form of HPS, which is often clinically undistinguishable from mild oculocutaneous or ocular forms of albinism. Molecular analysis is therefore required to establish the diagnosis of this mild HPS form, which has consequences in terms of prognosis and of clinical management of the patients.     

Mesenchymal Stem Cells (MSC) Prevented the Progression of Renovascular Hypertension,Improved Renal Function and Architecture

Renovascular hypertension induced by 2 Kidney-1 Clip (2K-1C) is a renin-angiotensin-system (RAS)-dependent model, leading to renal vascular rarefaction and renal failure. RAS inhibitors are not able to reduce arterial pressure (AP) and/or preserve the renal function, and thus, alternative therapies are needed. Three weeks after left renal artery occlusion, fluorescently tagged mesenchymal stem cells (MSC) (2×10⁵ cells/animal) were injected weekly into the tail vein in 2K-1C hypertensive rats. Flow cytometry showed labeled MSC in the cortex and medulla of the clipped kidney. MSC prevented a further increase in the AP, significantly reduced proteinuria and decreased sympathetic hyperactivity in 2K-1C rats. Renal function parameters were unchanged, except for an increase in urinary volume observed in 2K-1C rats, which was not corrected by MSC. The treatment improved the morphology and decreased the fibrotic areas in the clipped kidney and also significantly reduced renal vascular rarefaction typical of 2K-1C model. Expression levels of IL-1β, TNF-α angiotensinogen, ACE, and Ang II receptor AT₁ were elevated, whereas AT₂ levels were decreased in the medulla of the clipped kidney. MSC normalized these expression levels. In conclusion, MSC therapy in the 2K-1C model (i) prevented the progressive increase of AP, (ii) improved renal morphology and microvascular rarefaction, (iii) reduced fibrosis, proteinuria and inflammatory cytokines, (iv) suppressed the intrarenal RAS, iv) decreased sympathetic hyperactivity in anesthetized animals and v) MSC were detected at the CNS suggesting that the cells crossed the blood-brain barrier. This therapy may be a promising strategy to treat renovascular hypertension and its renal consequences in the near future.     

A horizon scanning assessment of current and potential future threats to migratory shorebirds

We review the conservation issues facing migratory shorebird populations that breed in temperate regions and use wetlands in the non‐breeding season. Shorebirds are excellent model organisms for understanding ecological, behavioural and evolutionary processes and are often used as indicators of wetland health. A global team of experienced shorebird researchers identified 45 issues facing these shorebird populations, and divided them into three categories (natural, current anthropogenic and future issues). The natural issues included megatsunamis, volcanoes and regional climate changes, while current anthropogenic threats encompassed agricultural intensification, conversion of tidal flats and coastal wetlands by human infrastructure developments and eutrophication of coastal systems. Possible future threats to shorebirds include microplastics, new means of recreation and infectious diseases. We suggest that this review process be broadened to other taxa to aid the identification and ranking of current and future conservation actions.     

Ultrastructure of Bacterial Cells Infected with Bacteriophage PM2, a Lipid-containing Bacterial Virus

The cytological pattern of infection of a host pseudomonad with PM2, a lipid-containing bacterial virus, was investigated by electron microscopy. Normal and infected cells frequently contain a myelin figure, which is found in the nucleoid region or at the periphery of the cell. The most striking finding in this investigation was that completed virions are found in the cell adjacent to or in association with the cytoplasmic membrane. This localization is precise; virions are not found elsewhere in infected cells. The completed virions occasionally appear to be attached to the cytoplasmic membrane. The virus contains a darkly staining core surrounded by a tripartite envelope of a thickness of approximately 70 A, which is identical to the thickness of the cytoplasmic membrane. Lysing cells appear to undergo extensive damage of the cytoplasmic membrane prior to rupture of the L layer of the cell wall.     

α-Bn-o-AMPA as a cis peptide bond mimic in somatostatin analogues

Summary In a previous communication we reported the racemic synthesis of the cis peptide bond mimic α-benzyl-o-aminomethylphenylacetic acid and its incorporation in the cyclic somatostatin analoguesc[α(R andS)Bn-o-AMPA-Phe⁷-d-Trp⁸-Lys⁹-Thr¹⁰]. Since the epimeric peptides exhibit different binding affinities, we completed the structure-activity study with an asymmetric synthesis. A model for the solution conformation ofc[α(R andS)Bn-o-AMPA-Phe⁷-d-Trp⁸-Lys⁹-Thr¹⁰] is proposed on the basis of a 2D NMR study in CD₃OH and restrained molecular dynamics.