Involvement of polyamines in the maturation of grapevine (Vitis vinifera L. ‘Mencía’) somatic embryos over a semipermeable membrane

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGThe endogenous content of polyamines and the expression of genes involved in their metabolism were analyzed in grapevine (Vitis vinifera L. ‘Mencía’) somatic embryo aggregates to determine the effect of a semipermeable membrane on their maturation in differentiation medium. The endogenous polyamine content in the somatic embryo aggregates was higher in those cultured over the semipermeable membrane and significantly increased with culture time due to an increase in the free polyamine fraction. Free putrescine represented more than 95% of the total free polyamine fraction and significantly peaked in the second week of culture of the somatic embryo aggregates over the semipermeable membrane. This finding appears to be supported by active expression of the VvADC gene and the low free spermidine level. Another significant peak of free putrescine was detected at the end of culture over the membrane, in which free spermidine level remained low despite the VvSPDS2 gene was upregulated. Hence, it is advisable that this increase in free putrescine was supported by back conversion from spermidine through VvPAO expression. As the semipermeable membrane successfully avoided precocious germination of the grapevine somatic embryos, the results support that polyamine metabolism, particularly putrescine metabolism, is involved in their correct maturation.Ministerio de Ciencia e Innovación | Ref. AGL2009–0748

Aurorae observed by Giuseppe Toaldo in Padua (1766–1797)

Se presenta un registro de las observaciones de auroras hechas por Giuseppe Toaldo y su asistente Vincenzo Chiminello en Padua, Italia, en la segunda mitad del siglo XVIII. Las fuentes históricas consultadas incluyen los manuscritos originales que contienen los registros meteorológicos realizados por esos dos observadores. Se construye un pequeño catálogo con las 148 observaciones aurorales. Las características de estas observaciones son analizadas. La principal característica de este conjunto de datos es que el número anual de observaciones aurorales presenta un pico intenso alrededor de 1779 y una disminución abrupta alrededor de 1790.A record is presented of the auroral observations made by Giuseppe Toaldo and his assistant Vincenzo Chiminello in Padua, Italy, in the second half of the 18th century. The historical sources consulted include the original manuscripts containing the meteorological records made by those two observers. A small catalogue is constructed with the 148 auroral observations. The characteristics of these observations are analysed. The main feature of this data set is that the annual number of auroral observations presents an intense peak at around 1779 and an abrupt decline at around 1790.• Ministerio de Ciencia e Innovación. Proyectos AYA2008-04864/AYA y AYA2014-57556-P • Junta de Extremadura. Ayuda para Grupos de Investigación GR15137 • Universidad de las Fuerzas Armadas of Ecuador (ESPE). Proyecto 2015-PIC-014 • Gobierno de Ecuador. Secretaría de Educación Superior, Ciencia, Tecnología e Innovación. Proyecto PROMETEO, para Fernando Domínguez CastropeerReviewe

Vitamin D deficiency as a potential risk factor for accelerated aging, impaired hippocampal neurogenesis and cognitive decline: a role for Wnt/β-catenin signaling

Vitamin D is an essential fat-soluble vitamin that participates in several homeostatic functions in mammalian organisms. Lower levels of vitamin D are produced in the older population, vitamin D deficiency being an accelerating factor for the progression of the aging process. In this review, we focus on the effect that vitamin D exerts in the aged brain paying special attention to the neurogenic process. Neurogenesis occurs in the adult brain in neurogenic regions, such as the dentate gyrus of the hippocampus (DG). This region generates new neurons that participate in cognitive tasks. The neurogenic rate in the DG is reduced in the aged brain because of a reduction in the number of neural stem cells (NSC). Homeostatic mechanisms controlled by the Wnt signaling pathway protect this pool of NSC from being depleted. We discuss in here the crosstalk between Wnt signaling and vitamin D, and hypothesize that hypovitaminosis might cause failure in the control of the neurogenic homeostatic mechanisms in the old brain leading to cognitive impairment. Understanding the relationship between vitamin D, neurogenesis and cognitive performance in the aged brain may facilitate prevention of cognitive decline and it can open a door into new therapeutic fields by perspectives in the elderly.Ministerio de Ciencia, Innovación y Universidades RTI2018-099908-B-C21FEDER-UCA18-1066

Evolution of Experimental Models in the Study of Glioblastoma: Toward Finding Efficient Treatments

Glioblastoma (GBM) is the most common form of brain tumor characterized by its resistance to conventional therapies, including temozolomide, the most widely used chemotherapeutic agent in the treatment of GBM. Within the tumor, the presence of glioma stem cells (GSC) seems to be the reason for drug resistance. The discovery of GSC has boosted the search for new experimental models to study GBM, which allow the development of new GBM treatments targeting these cells. In here, we describe different strategies currently in use to study GBM. Initial GBM investigations were focused in the development of xenograft assays. Thereafter, techniques advanced to dissociate tumor cells into single-cell suspensions, which generate aggregates referred to as neurospheres, thus facilitating their selective expansion. Concomitantly, the finding of genes involved in the initiation and progression of GBM tumors, led to the generation of mice models for the GBM. The latest advances have been the use of GBM organoids or 3D-bioprinted mini-brains. 3D bio-printing mimics tissue cytoarchitecture by combining different types of cells interacting with each other and with extracellular matrix components. These in vivo models faithfully replicate human diseases in which the effect of new drugs can easily be tested. Based on recent data from human glioblastoma, this review critically evaluates the different experimental models used in the study of GB, including cell cultures, mouse models, brain organoids, and 3D bioprinting focusing in the advantages and disadvantages of each approach to understand the mechanisms involved in the progression and treatment response of this devastating disease

12-Deoxyphorbols Promote Adult Neurogenesis by Inducing Neural Progenitor Cell Proliferation via PKC Activation

Background: Neuropsychiatric and neurological disorders frequently occur after brain insults associated with neuronal loss. Strategies aimed to facilitate neuronal renewal by promoting neurogenesis constitute a promising therapeutic option to treat neuronal death-associated disorders. In the adult brain, generation of new neurons occurs physiologically throughout the entire life controlled by extracellular molecules coupled to intracellular signaling cascades. Proteins participating in these cascades within neurogenic regions constitute potential pharmacological targets to promote neuronal regeneration of injured areas of the central nervous system. Methodology: We have performed in vitro and in vivo approaches to determine neural progenitor cell proliferation to understand whether activation of kinases of the protein kinase C family facilitates neurogenesis in the adult brain. Results: We have demonstrated that protein kinase C activation by phorbol-12-myristate-13-acetate induces neural progenitor cell proliferation in vitro. We also show that the nontumorogenic protein kinase C activator prostratin exerts a proliferative effect on neural progenitor cells in vitro. This effect can be reverted by addition of the protein kinase C inhibitor G06850, demonstrating that the effect of prostratin is mediated by protein kinase C activation. Additionally, we show that prostratin treatment in vivo induces proliferation of neural progenitor cells within the dentate gyrus of the hippocampus and the subventricular zone. Finally, we describe a library of diterpenes with a 12-deoxyphorbol structure similar to that of prostratin that induces a stronger effect than prostratin on neural progenitor cell proliferation both in vitro and in vivo

Evidence on port-locking with heparin versus saline in patients with cancer not receiving chemotherapy: A randomized clinical trial

Objective: To assess the safety and efficacy of port-locking with heparin every 2 months vs. every 4 months and vs. saline solution every 2 months in patients with cancer not receiving active chemotherapy. The hypothesis stated that locking with heparin at four-month intervals and saline at two-month intervals would not increment > 10% of port obstructions. Methods: Multicentre, phase IV parallel, post-test control group study took place at the two chemotherapy units of oncology hospitals. Included patients with cancer with ports that completed the chemotherapy treatment but still having port maintenance care or blood samples taken up to four months. A sample of 126 patients with cancer in three arms was needed to detect a maximum difference of 10% for bioequivalence on the locking methods. Consecutive cases non-probabilistic sampling and randomized to one of the three groups; group A: received heparin 60 IU/mL every two months (control) vs. group B heparin every four months and vs. saline every two months in group C. Primary variables were the type of locking regimen, port obstruction, and absence of blood return, port-related infection, or venous thrombosis during the study period. Clinical and sociodemographic variables were also collected. Results: A total of 143 patients were randomly assigned; group A, 47 patients with heparin every 2 months, group B, 51 patients with heparin 4 months, and group C, 45 patients with saline every 2 months. All participants presented an adequate blood return and no obstructions, until the month of the 10th, when one participant in the group A receiving was withdrawn due to an absence of blood flow ( P 1/4 0.587). Conclusions: Port locks with heparin every 4 months or saline every 2 months did not show differences in safety maintenance, infection, or thrombosis compared to heparin every 2 months

Rescue of neurogenesis and age-associated cognitive decline in SAMP8 mouse: Role of transforming growth factor-alpha

Neuropathological aging is associated with memory impairment and cognitive decline, affecting several brain areas including the neurogenic niche of the dentate gyrus of the hippocampus (DG). In the healthy brain, homeostatic mechanisms regulate neurogenesis within the DG to facilitate the continuous generation of neurons from neural stem cells (NSC). Nevertheless, aging reduces the number of activated neural stem cells and diminishes the number of newly generated neurons. Strategies that promote neurogenesis in the DG may improve cognitive performance in the elderly resulting in the development of treatments to prevent the progression of neurological disorders in the aged population. Our work is aimed at discovering targeting molecules to be used in the design of pharmacological agents that prevent the neurological effects of brain aging. We study the effect of age on hippocampal neurogenesis using the SAMP8 mouse as a model of neuropathological aging. We show that in 6-month-old SAMP8 mice, episodic and spatial memory are impaired; concomitantly, the generation of neuroblasts and neurons is reduced and the generation of astrocytes is increased in this model. The novelty of our work resides in the fact that treatment of SAMP8 mice with a transforming growth factor-alpha (TGFα) targeting molecule prevents the observed defects, positively regulating neurogenesis and improving cognitive performance. This compound facilitates the release of TGFα in vitro and in vivo and activates signaling pathways initiated by this growth factor. We conclude that compounds of this kind that stimulate neurogenesis may be useful to counteract the neurological effects of pathological aging.19 página

Axonal Guidance Using Biofunctionalized Straining Flow Spinning Regenerated Silk Fibroin Fibers as Scaffold

After an injury, the limited regenerative capacity of the central nervous system makes the reconnection and functional recovery of the affected nervous tissue almost impossible. To address this problem, biomaterials appear as a promising option for the design of scaffolds that promote and guide this regenerative process. Based on previous seminal works on the ability of regenerated silk fibroin fibers spun through the straining flow spinning (SFS) technique, this study is intended to show that the usage of functionalized SFS fibers allows an enhancement of the guidance ability of the material when compared with the control (nonfunctionalized) fibers. It is shown that the axons of the neurons not only tend to follow the path marked by the fibers, in contrast to the isotropic growth observed on conventional culture plates, but also that this guidance can be further modulated through the biofunctionalization of the material with adhesion peptides. Establishing the guidance ability of these fibers opens the possibility of their use as implants for spinal cord injuries, so that they may represent the core of a therapy that would allow the reconnection of the injured ends of the spinal cord.Unidad Docente de Biodiversidad, Ecología y EvoluciónFac. de Óptica y OptometríaTRUEMinisterio de Ciencia e Innovación de EspañaComunidad de Madrid (España)Banco Santander (España)Universidad Complutense de Madrid (España)pu

Effects of classical PKC activation on hippocampal neurogenesis and cognitive performance: mechanism of action

Hippocampal neurogenesis has widely been linked to memory and learning performance. New neurons generated from neural stem cells (NSC) within the dentate gyrus of the hippocampus (DG) integrate in hippocampal circuitry participating in memory tasks. Several neurological and neuropsychiatric disorders show cognitive impairment together with a reduction in DG neurogenesis. Growth factors secreted within the DG promote neurogenesis. Protein kinases of the protein kinase C (PKC) family facilitate the release of several of these growth factors, highlighting the role of PKC isozymes as key target molecules for the development of drugs that induce hippocampal neurogenesis. PKC activating diterpenes have been shown to facilitate NSC proliferation in neurogenic niches when injected intracerebroventricularly. We show in here that long-term administration of diterpene ER272 promotes neurogenesis in the subventricular zone and in the DG of mice, affecting neuroblasts differentiation and neuronal maturation. A concomitant improvement in learning and spatial memory tasks performance can be observed. Insights into the mechanism of action reveal that this compound facilitates classical PKC alpha activation and promotes transforming growth factor alpha (TGF alpha) and, to a lesser extent, neuregulin release. Our results highlight the role of this molecule in the development of pharmacological drugs to treat neurological and neuropsychiatric disorders associated with memory loss and a deficient neurogenesis