Efecto de las auxinas e insulina en la síntesis y fosforilación de proteínas de la parte aérea de ejes embrionarios de maíz (Zea Mays L.)

Las auxinas y la insulina promueven el crecimiento de embriones de maíz (Zea mays L.), inducen la fosforilación de la proteína ribosomal S6 (prS6) y promueven la síntesis de proteínas específicas. El objetivo de esta investigación fue probar el posible entrecruzamiento entre las vías de transducción de insulina y auxinas en coleóptilos de maíz, tejidos blanco típico de auxinas. Las auxinas y la insulina produjeron una estimulación diferencial cuantitativa y cualitativa de la fosforilación de proteínas citoplásmicas y ribosomales, así como patrones específicos de proteínas citoplásmicas sintetizadas de novo. Además la inducción de la fosforilación de prS6 por insulina fue inhibida fuertemente por rapamicina, indicando la participación de la cinasa blanco de rapamicina (TOR), mientras que la fosforilación de prS6 inducida por auxinas fue insensible a este inhibidor. Se probó también ácido fosfatídico (PA), un segundo mensajero de TOR en metazoarios. Este compuesto produjo resultados similares a los obtenidos con insulina y la sensibilidad a rapamicina también fue semejante, apoyando la existencia de la vía TOR en plantas y la participación de PA como un intermediario de acción de insulina. Estos datos parecen implicar que las auxinas y la insulina inducen el crecimiento de coleóptilos de maíz a través de dos vías de transducción de señales independientes.Auxin and insulin promote maize (Zea mays) embryo growth, induce S6 ribosomal protein (S6rp) phosphorylation, and promote specific protein synthesis. The objective of this research was to test a possible cross-talk between insulin and auxin transduction pathway in maize coleoptiles, typical auxin target tissue. Auxin and insulin produced differential quantitative and qualitative stimulation of cytoplasmic and ribosomal protein phosphorylation, and specific patterns of de novo synthesized cytoplasmic proteins. In addition, insulin induced S6rp phosphorylation was strongly inhibited by rapamycin, indicating target of rapamycin (TOR) kinase participation, auxin-induced S6rp phosphorylation was insensitive to this inhibitor. Phosphatidic acid (PA), as second Messenger of TOR in metazoan, was also tested. It produced similar results to insulin and rapamycin sensitiveness, supporting the existence of TOR pathway in plants and the participation of PA as an intermediate of insulin action. These results seem to imply that auxin and insulin induce maize coleoptile growth throug two independent signal transduction pathways

Future Perspectives of Therapeutic, Diagnostic and Prognostic Aptamers in Eye Pathological Angiogenesis

Aptamers are single-stranded DNA or RNA oligonucleotides that are currently used in clinical trials due to their selectivity and specificity to bind small molecules such as proteins, peptides, viral particles, vitamins, metal ions and even whole cells. Aptamers are highly specific to their targets, they are smaller than antibodies and fragment antibodies, they can be easily conjugated to multiple surfaces and ions and controllable post-production modifications can be performed. Aptamers have been therapeutically used for age-related macular degeneration, cancer, thrombosis and inflammatory diseases. The aim of this review is to highlight the therapeutic, diagnostic and prognostic possibilities associated with aptamers, focusing on eye pathological angiogenesis

Human Amniotic Membrane Mesenchymal Stem Cell-Synthesized PGE₂ Exerts an Immunomodulatory Effect on Neutrophil Extracellular Trap in a PAD-4-Dependent Pathway through EP2 and EP4

Human amniotic membrane mesenchymal stem cells (hAM-MSC) secrete a myriad of components with immunosuppressive activities. In the present research, we aimed to describe the effect of prostaglandin E2 (PGE2) secreted by hAM-MSCs on neutrophil extracellular trap (NET) release and to characterize the role of its receptors (EP2/EP4) in PAD-4 and NFκB activity in neutrophils. Human peripheral blood neutrophils were ionomycin-stimulated in the presence of hAM-MSC conditioned medium (CM) treated or not with the selective PGE2 inhibitor MF-63, PGE2, EP2/EP4 agonists, and the selective PAD-4 inhibitor GSK-484. NET release, PAD-4, and NFκB activation were analyzed. Ionomycin induced NET release, which was inhibited in the presence of hAM-MSC-CM, while CM from hAM-MSCs treated with MF-63 prevented NET release inhibition. PGE2 and EP2/EP4 agonists, and GSK-484 inhibited NET release. EP2/EP4 agonists and GSK-484 inhibited H3-citrullination but did not affect PAD-4 protein expression. Finally, PGE2 and EP2/EP4 agonists and GSK-484 increased NFκB phosphorylation. Taken together, these results suggest that hAM-MSC exert their immunomodulatory activities through PGE2, inhibiting NET release in a PAD-4-dependent pathway. This research proposes a new mechanism by which hAM-MSC exert their activities when modulating the innate immune response and inhibiting NET release

AS1411 Nucleolin-Specific Binding Aptamers Reduce Pathological Angiogenesis through Inhibition of Nucleolin Phosphorylation

Proliferative retinopathies produces an irreversible type of blindness affecting working age and pediatric population of industrialized countries. Despite the good results of anti-VEGF therapy, intraocular and systemic complications are often associated after its intravitreal use, hence novel therapeutic approaches are needed. The aim of the present study is to test the effect of the AS1411, an antiangiogenic nucleolin-binding aptamer, using in vivo, ex vivo and in vitro models of angiogenesis and propose a mechanistic insight. Our results showed that AS1411 significantly inhibited retinal neovascularization in the oxygen induced retinopathy (OIR) in vivo model, as well as inhibited branch formation in the rat aortic ex vivo assay, and, significantly reduced proliferation, cell migration and tube formation in the HUVEC in vitro model. Importantly, phosphorylated NCL protein was significantly abolished in HUVEC in the presence of AS1411 without affecting NFκB phosphorylation and -21 and 221-angiomiRs, suggesting that the antiangiogenic properties of this molecule are partially mediated by a down regulation in NCL phosphorylation. In sum, this new research further supports the NCL role in the molecular etiology of pathological angiogenesis and identifies AS1411 as a novel anti-angiogenic treatment