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Artículos Científicos

Th17 polarization of memory Th cells in early arthritis: the vasoactive intestinal peptide effect

J Leukoc Biol. 2015; pii: jlb.3A0714-327R.

Jimeno R, Leceta J, Garín M, Ortiz AM, Mellado M, Rodríguez-Frade JM, Martínez C, Pérez-García S, Gomariz RP, Juarranz Y.

J Leukoc Biol. 2015; pii: jlb.3A0714-327RSeveral studies in humans indicate the implication of Th17 cells in RA. Therapies targeting their pathogenicity, as well as their plasticity to the Th17/1 phenotype, could ameliorate the progression of the pathology. The neuroendocrine environment has a major impact on the differentiation of lymphoid cells. VIP is present in the microenvironment of the joint, and its known therapeutic effects are supported by several studies on RA.

We examine the ability of VIP to modulate the differentiation of Th17 cells. Peripheral blood CD4+CD45RO+ T cells from HD and eRA patients were expanded under Th17-polarizing conditions in the presence of TGF-β. After 7 days, the higher IL-17A, IL-21, and IL-9 levels and lower IL-22 levels indicate the nonpathogenic profile for Th17 cells in HD. In contrast, Th17 cells from eRA patients produced significantly more IL-22 and IFN-γ, and these cells show a more Th17/1 profile, indicating a pathogenic phenotype. Interestingly, when VIP was present in the Th17 conditioned medium, increased levels of IL-10 and IL-9 were detected in HD and eRA patients. VIP also reduced the levels of IL-22 in eRA patients. These data suggest that VIP reduces the pathogenic profile of the Th17-polarized cells. This effect was accompanied by an increased in the Treg/Th17 profile, as shown by the increase levels of Foxp3.

In conclusion, this report addresses a novel and interesting question on the effect of VIP on human Th17 cells and adds clinical relevance by analyzing, in parallel, HD and eRA patients. .

p38 MAPK down-regulates fibulin 3 expression through methylation of gene regulatory sequences: role in migration and invasion

J Biol Chem. 2015; 290 (7): 4383-4397.

Arechederra M, Priego N, Vázquez-Carballo A, Sequera C, Gutiérrez-Uzquiza Á, Cerezo-Guisado MI, Ortiz-Rivero S, Roncero C, Cuenda A, Guerrero C, Porras A.

J Biol Chem. 2015; 290 (7): 4383-4397p38 MAPKs regulate migration and invasion. However, the mechanisms involved are only partially known.

We had previously identified fibulin 3, which plays a role in migration, invasion, and tumorigenesis, as a gene regulated by p38α. We have characterized in detail how p38 MAPK regulates fibulin 3 expression and its role. We describe here for the first time that p38α, p38γ, and p38δ down-regulate fibulin 3 expression. p38α has a stronger effect, and it does so through hypermethylation of CpG sites in the regulatory sequences of the gene. This would be mediated by the DNA methylase, DNMT3A, which is down-regulated in cells lacking p38α, but once re-introduced represses Fibulin 3 expression. p38α through HuR stabilizes dnmt3a mRNA leading to an increase in DNMT3A protein levels. Moreover, by knocking-down fibulin 3, we have found that Fibulin 3 inhibits migration and invasion in MEFs by mechanisms involving p38α/β inhibition. Hence, p38α pro-migratory/invasive effect might be, at least in part, mediated by fibulin 3 down-regulation in MEFs. In contrast, in HCT116 cells, Fibulin 3 promotes migration and invasion through a mechanism dependent on p38α and/or p38β activation. Furthermore, Fibulin 3 promotes in vitro and in vivo tumor growth of HCT116 cells through a mechanism dependent on p38α, which surprisingly acts as a potent inducer of tumor growth. At the same time, p38α limits fibulin 3 expression, which might represent a negative feed-back loop.

RNA polymerase slippage as a mechanism for the production of frameshift gene products in plant viruses of the Potyviridae family

J Virol. 2015; pii: JVI.00337-15.

Rodamilans B, Valli A, Mingot A, San León D, Baulcombe D, López-Moya JJ, García JA.

J Virol. 2015; pii: JVI.00337-15Modifications of RNA sequences by nucleotide insertions, deletions or substitutions can result in expression of multiple proteins in overlapping open reading frames (ORF).

In the case of viruses, polymerase slippage results in the alteration of newly synthesized RNA. The mechanism has been well characterized in animal RN A viruses such as Ebolavirus (EBOV) or Hepatitis C virus (HCV). For plant viruses, polymerase slippage has been proposed as a general process for viral evolution in members of the Potyviridae family , although lack of experimental systems have precluded confirmatory data, and most pieces of evidence are indirect.

Structural characterization of toxic oligomers that are kinetically trapped during α-synuclein fibril formation

Proc Natl Acad Sci USA. 2015; pii: 201421204.

Chen SW, Drakulic S, Deas E, Ouberai M, Aprile FA, Arranz R, Ness S, Roodveldt C, Guilliams T, De-Genst EJ, Klenerman D, Wood NW, Knowles TP, Alfonso C, Rivas G, Abramov AY, Valpuesta JM, Dobson CM, Cremades N.

Proc Natl Acad Sci USA. 2015; pii: 201421204We describe the isolation and detailed structural characterization of stable toxic oligomers of α-synuclein that have accumulated during the process of amyloid formation. Our approach has allowed us to identify distinct subgroups of oligomers and to probe their molecular architectures by using cryo-electron microscopy (cryoEM) image reconstruction techniques.

Although the oligomers exist in a range of sizes, with different extents and nature of β-sheet content and exposed hydrophobicity, they all possess a hollow cylindrical architecture with similarities to certain types of amyloid fibril, suggesting that the accumulation of at least some forms of amyloid oligomers is likely to be a consequence of very slow rates of rearrangement of their β-sheet structures. Our findings reveal the inherent multiplicity of the process of protein misfolding and the key role the β-sheet geometry acquired in the early stages of the self-assembly process plays in dictating the kinetic stability and the pathological nature of individual oligomeric species.

Characterization of interaction of magnetic nanoparticles with breast cancer cells

J Nanobiotechnology. 2015; 13(1): 16.

Calero M, Chiappi M, Lazaro-Carrillo A, Rodríguez MJ, Chichón FJ, Crosbie-Staunton K, Prina-Mello A, Volkov Y, Villanueva A, Carrascosa JL.

J Nanobiotechnology. 2015; 13(1): 16Different superparamagnetic iron oxide nanoparticles have been tested for their potential use in cancer treatment, as they enter into cells with high effectiveness, do not induce cytotoxicity, and are retained for relatively long periods of time inside the cells. We have analyzed the interaction, internalization and biocompatibility of dimercaptosuccinic acid-coated superparamagnetic iron oxide nanoparticles with an average diameter of 15 nm and negative surface charge in MCF-7 breast cancer cells.

Cells were incubated with dimercaptosuccinic acid-coated superparamagnetic iron oxide nanoparticles for different time intervals, ranging from 0.5 to 72 h. These nanoparticles showed efficient internalization and relatively slow clearance. Time-dependent uptake studies demonstrated the maximum accumulation of dimercaptosuccinic acid-coated superparamagnetic iron oxide nanoparticles after 24 h of incubation, and afterwards they were slowly removed from cells. Superparamagnetic iron oxide nanoparticles were internalized by energy dependent endocytosis and localized in endosomes. Transmission electron microscopy studies showed macropinocytosis uptake and clathrin-mediated internalization depending on the nanoparticles aggregate size. MCF-7 cells accumulated these nanoparticles without any significant effect on cell morphology, cytoskeleton organization, cell cycle distribution, reactive oxygen species generation and cell viability, showing a similar behavior to untreated control cells.

All these findings indicate that dimercaptosuccinic acid-coated superparamagnetic iron oxide nanoparticles have excellent properties in terms of efficiency and biocompatibility for application to target breast cancer cells.