Establishment of permanent human endothelial cells achieved by transfection with SV40 large T antigen that retain typical phenotypical and functional characteristics

Summary The plasmid pMK16 containing-SV40 replicated origin defective gene was efficiently introduced into early-passage human umbilical vein endothelial cells (HUVEC) using positively charged liposomes. The resulting cell line acquired an almost infinite lifespan, was morphologically unchanged, expressed SV40-antigen, and coexpressed von Willebrand factor (vWF), tissue plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1), angiotensin conversion enzyme (ACE), and endothelin converting enzyme (ECE). In addition, these are the first immortalized human endothelial cells, to our knowledge, that biosynthesized and secreted interleukins (IL-1β and IL-6) in both a constitutive and regulated fashion and endothelin-1 (ET-1), the most potent vasoactive peptide, which has been suggested to be implicated in the pathogenesis of hypertension. Interestingly enough, both of the immortalized cells and the early-passage HUVEC from which the immortalized cells were obtained biosynthesized and secreted the same levels of ET-1 suggesting full maintenance of its biosynthetic pathway including the presence of active ECE, which cleaves big endothelin-1 (big-ET-1) to ET-1 and regulation factors. Moreover, the immortalized cells retained the ability to express the functional specific amino acid Na⁺-independent system Y⁺ transporter, which mediates L-arginine transport into endothelial cells from which endothelium-derived relaxing factor (EDRF, nitric oxide) is formed via the action of nitric oxide-synthase. Obtaining these immortalized human endothelial cells without alteration of the differentiated characteristics constitutes a useful model: (a) to study ET-1 secretion, gene regulation, and human ECE, which may be an important therapeutic target in disease conditions in which ET-1 is to be implicated; (b) to study L-arginine transport, which is a key step in the formation of EDRF; (c) to study IL-1β and IL-6 secretions, and gene regulations; (d) to substitute large quantities of HUVEC; and, finally, (e) to reproduce, starting with different primary endothelial cells both from human and animal origin.     

New Method for Evaluating Antibacterial Activity Directly on Fabric

Bacteriostasis of treated fabric was evaluated directly by a colony count made on the treated fabric after impregnation with seeded agar containing triphenyltetrazolium chloride and incubation in a horizontal, suspended position in a petri dish.     

One-pot three-component synthesis of novel spirooxindoles with potential cytotoxic activity against triple-negative breast cancer MDA-MB-231 cells

Triple-negative breast cancer (TNBC) is a highly aggressive malignancy with limited treatment options due to its heterogeneity and the lack of well-defined molecular targets. In our endeavour towards the development of novel anti-TNBC agents, herein we report a one-pot three-component synthesis of novel spirooxindoles 6a–p, and evaluation of their potential anti-proliferative activity towards TNBC MDA-MB-231 cells. Spirooxindoles 6a, 6e and 6i emerged as the most potent analogues with IC₅₀ =?6.70, 6.40 and 6.70?µM, respectively. Compounds 6a and 6e induced apoptosis in MDA-MB-231 cells, as evidenced by the up-regulation of the Bax and down-regulation of the Bcl-2, besides boosting caspase-3 levels. Additionally, 6e displayed significant increase in the percent of annexin V-FITC positive apoptotic cells from 1.34 to 44%. Furthermore, spirooxindoles 6e and 6i displayed good inhibitory activity against EGFR (IC₅₀ =?120 and 150?nM, respectively). Collectively, these data demonstrated that 6e might be a potential lead compound for the development of effective anti-TNBC agents.     

Adult Ceramide Synthase 2 (CERS2)-deficient Mice Exhibit Myelin Sheath Defects, Cerebellar Degeneration, and Hepatocarcinomas

(Dihydro)ceramide synthase 2 (cers2, formerly called lass2) is the most abundantly expressed member of the ceramide synthase gene family, which includes six isoforms in mice. CERS2 activity has been reported to be specific toward very long fatty acid residues (C22–C24). In order to study the biological role of CERS2, we have inactivated its coding region in transgenic mice using gene-trapped embryonic stem cells that express lacZ reporter DNA under control of the cers2 promoter. The resulting mice lack ceramide synthase activity toward C24:1 in the brain as well as the liver and show only very low activity toward C18:0–C22:0 in liver and reduced activity toward C22:0 residues in the brain. In addition, these mice exhibit strongly reduced levels of ceramide species with very long fatty acid residues (≥C22) in the liver, kidney, and brain. From early adulthood on, myelin stainability is progressively lost, biochemically accompanied by about 50% loss of compacted myelin and 80% loss of myelin basic protein. Starting around 9 months, both the medullary tree and the internal granular layer of the cerebellum show significant signs of degeneration associated with the formation of microcysts. Predominantly in the peripheral nervous system, we observed vesiculation and multifocal detachment of the inner myelin lamellae in about 20% of the axons. Beyond 7 months, the CERS2-deficient mice developed hepatocarcinomas with local destruction of tissue architecture and discrete gaps in renal parenchyma. Our results indicate that CERS2 activity supports different biological functions: maintenance of myelin, stabilization of the cerebellar as well as renal histological architecture, and protection against hepatocarcinomas.     

Interactions between antimalarial indolone-N-oxide derivatives and human serum albumin

The binding affinity of human serum albumin (HSA) to three antimalarial indolone-N-oxide derivatives, INODs, was investigated under simulated physiological conditions using fluorescence spectroscopy in combination with UV-vis absorption and circular dichroism (CD) spectroscopy. Analysis of fluorescence quenching data of HSA by these compounds at different temperatures using Stern-Volmer and Lineweaver-Burk methods revealed the formation of a ground state indolone-HSA complex with binding affinities of the order 10(4) M(-1). The thermodynamic parameters ΔG, ΔH, and ΔS, calculated at different temperatures, indicated that the binding reaction was endothermic and hydrophobic interactions play a major role in this association. The conformational changes of HSA were investigated qualitatively using synchronous fluorescence and quantitatively using CD. Site marker competitive experiments showed that the binding process took place primarily at site I (subdomain IIA) of HSA. The number of binding sites and the apparent binding constants were also studied in the presence of different ions.     

Recombination suppression at the dominant <Emphasis Type="Italic">Rhg1/Rfs2</Emphasis> locus underlying soybean resistance to the cyst nematode

Host resistance to “yellow dwarf” or “moonlight” disease cause by any population (Hg type) of Heterodera glycines I., the soybean cyst nematode (SCN), requires a functional allele at rhg1. The host resistance encoded appears to mimic an apoptotic response in the giant cells formed at the nematode feeding site about 24–48 h after nematode feeding commences. Little is known about how the host response to infection is mediated but a linked set of 3 genes has been identified within the rhg1 locus. This study aimed to identify the role of the genes within the locus that includes a receptor-like kinase (RLK), a laccase and an ion antiporter. Used were near isogeneic lines (NILs) that contrasted at their rhg1 alleles, gene-based markers, and a new Hg type 0 and new recombination events. A syntenic gene cluster on Lg B1 was found. The effectiveness of SNP probes from the RLK for distinguishing homolog sequence variants on LgB1 from alleles at the rhg1 locus on LgG was shown. The resistant allele of the rhg1 locus was shown to be dominant in NILs. None of the recombination events were within the cluster of the three candidate genes. Finally, rhg1 was shown to reduce the plant root development. A model for rhg1 as a dominant multi-gene resistance locus based on the developmental control was inferred.     

Separation and mass spectrometric characterization of covalently bound skin ceramides using LC/APCI-MS and Nano-ESI-MS/MS

Ceramides covalently bound to keratinocytes are essential for the barrier function of the skin, which can be disturbed in diseases, such as psoriasis and atopic dermatitis. These ceramides of the classes omega-hydroxyacyl-sphingosine and omega-hydroxyacyl-6-hydroxysphingosine contain an omega-hydroxy fatty acid. For their separation and identification, a new analytical approach based on normal phase liquid chromatography coupled to atmospheric pressure chemical ionization mass spectrometry and tandem nano-electrospray mass spectrometry, respectively, is presented here. Tandem mass spectrometry provided structural information about the sphingoid base as well as the fatty acid moieties. The chain lengths of the bases ranged from C12 to C22, the chain lengths of the fatty acids varied between C28 and C36. In total, 67 ceramide species have been identified in human skin. The analytical methods presented in this work can be helpful for investigating alterations in the ceramide composition of the skin as seen in psoriasis, atopic dermatitis, and diseases with impaired epidermal barrier function.