Efecto diferencial del calcitriol y del paricalcitol sobre el proceso de calcificación en células de músculo liso vascular. Mecanismos intracelulares implicados

La primera causa de muerte en pacientes con Enfermedad Renal Crónica (ERC) es la enfermedad cardiovascular (ECV), siendo su índice al menos 20 veces más alto en pacientes en diálisis que en la población general. Los pacientes con ERC sufren hiperfosfatemia y otras alteraciones del metabolismo mineral que les conducen al desarrollo de Hiperparatiroidismo Secundario (HPT2o) y de calcificaciones vasculares (CV); estas últimas contribuyen a la alta tasa de morbilidad y mortalidad cardiovascular observada en estos pacientes. La CV es un proceso activo que implica la transformación osteogénica de las células de músculo liso vascular (CMLV), aunque los mecanismos celulares y moleculares por los que ocurren no están completamente definidos. Se ha descrito que niveles elevados de fosfato (PO) inducen la calcificación y la diferenciación de las CMLV. El calcitriol (CTR), molécula empleada en el tratamiento del HPT2o en las últimas décadas, induce hipercalcemia y un aumento del producto calcio x fósforo, favoreciendo el desarrollo de CV. Actualmente, se vienen usando análogos de la vitamina D menos calcémicos como el paricalcitol (PC), que ha resultado ser efectivo en el tratamiento del HPT2º sin inducir CV. No obstante, los mecanismos moleculares que median el efecto diferencial del calcitriol y del paricalcitol sobre las CV no están del todo claros. Uno de los objetivos de este estudio es determinar si los tratamientos con calcitriol o con paricalcitol modularán de manera desigual la calcificación, la transformación osteogénica y las vías de señalización intracelular relacionadas con la CV de las CMLV inducidas por niveles elevados de fosfato...Cardiovascular disease (CVD) is the main cause of death in patients with chronic kidney disease (CKD), with a frequency 20 times higher than the observed in the general population. CKD patients exhibit hyperphosphatemia and other disorders of mineral metabolism that lead to the development of Secondary Hyperparathyroidism (HPT2º) and vascular calcification (VC). Both of them contribute to the high rate of cardiovascular morbidity and mortality observed in uremic patients. CV is an active process involving osteogenic transformation of vascular smooth muscle cells (VSMC), although the underlying cellular and molecular mechanisms are not fully elucidated. It has been described that elevated levels of phosphate (PO) induce calcification and differentiation of VSMCs. Calcitriol (CTR), molecule which has been used for the treatment of HPT2º during the last decades, has an effect producing hypercalcemia and increasing the calcium x phosphorus product, as well as promoting the development of VC. Currently, less calcemic vitamin D analogues are being used. For instance, paricalcitol (PC) has been proved to be effective in controlling HPT2º without inducing VC. Nevertheless, the molecular mechanisms mediating the differential effect of CTR and PC are not entirely clear. One objective of this study is to determine whether treatment with CTR of PC will modulate differently calcification, osteogenic transformation and intracellular signaling pathways associated with high phosphate-induced VC. Furthermore, two of the main factors associated with the progression and severity of CKD are chronic inflammation and oxidative stress (OS), which have also been related to VC. However, it is unclear to what extent phosphate has a..

Balancing porosity and mechanical properties of titanium samples to favor cellular growth against bacteria

Two main problems limit the success of titanium implants: bacterial infection, which restricts their osseointegration capacity; and the stiffness mismatch between the implant and the host cortical bone, which promotes bone resorption and risk of fracture. Porosity incorporation may reduce this difference in stiffness but compromise biomechanical behavior. In this work, the relationship between the microstructure (content, size, and shape of pores) and the antibacterial and cellular behavior of samples fabricated by the space-holder technique (50 vol % NH4HCO3 and three ranges of particle sizes) is established. Results are discussed in terms of the best biomechanical properties and biofunctional activity balance (cell biocompatibility and antibacterial behavior). All substrates achieved suitable cell biocompatibility of premioblast and osteoblast in adhesion and proliferation processes. It is worth to highlighting that samples fabricated with the 100–200 μm space-holder present better mechanical behavior—in terms of stiffness, microhardness, and yield strength—which make them a very suitable material to replace cortical bone tissues. Those results exposed the relationship between the surface properties and the race of bacteria and mammalian cells for the surface with the aim to promote cellular growth over bacteria.University of Seville (Spain) VI Plan Propio de Investigación y Transferencia—US 2018, I.3A

The contribution of histone crotonylation to tissue health and disease: focus on kidney health

Acute kidney injury (AKI) and chronic kidney disease (CKD) are the most severe consequences of kidney injury. They are interconnected syndromes as CKD predisposes to AKI and AKI may accelerate CKD progression. Despite their growing impact on the global burden of disease, there is no satisfactory treatment for AKI and current therapeutic approaches to CKD remain suboptimal. Recent research has focused on the therapeutic target potential of epigenetic regulation of gene expression, including non-coding RNAs and the covalent modifications of histones and DNA. Indeed, several drugs targeting histone modifications are in clinical use or undergoing clinical trials. Acyllysine histone modifications (e.g. methylation, acetylation, and crotonylation) have modulated experimental kidney injury. Most recently, increased histone lysine crotonylation (Kcr) was observed during experimental AKI and could be reproduced in cultured tubular cells exposed to inflammatory stress triggered by the cytokine TWEAK. The degree of kidney histone crotonylation was modulated by crotonate availability and crotonate supplementation protected from nephrotoxic AKI. We now review the functional relevance of histone crotonylation in kidney disease and other pathophysiological contexts, as well as the implications for the development of novel therapeutic approaches. These studies provide insights into the overall role of histone crotonylation in health and diseaseSources of support: FIS/FEDER funds (PI15/00298, CP14/00133, PI16/02057, PI16/01900, PI18/01386, PI19/00588, PI19/00815, DTS18/00032, ERA-PerMed-JTC2018 (KIDNEY ATTACK AC18/00064 and PERSTIGAN AC18/00071), ISCIII-RETIC REDinREN RD016/0009), Sociedad Española de Nefrología, FRIAT, Comunidad de Madrid en Biomedicina B2017/BMD- 3686 CIFRA2-CM. Salary support: ISCIII Miguel Servet and to AS and MS-N, ISCIII Sara Borrell to JM-M and Comunidad de Madrid (B2017/BMD-3686 CIFRA2-CM) to MF-B and DM-S

In vascular smooth muscle cells paricalcitol prevents phosphate-induced Wnt/β-catenin activation

The present study investigates the differential effect of two vitamin D receptor agonists, calcitriol and paricalcitol, on human aortic smooth muscle cells calcification in vitro. Human vascular smooth muscle cells were incubated in a high phosphate (HP) medium alone or supplemented with either calcitriol 10−8M (HP + CTR) or paricalcitol 3·10−8 M (HP + PC). HP medium induced calcification, which was associated with the upregulation of mRNA expression of osteogenic factors such as bone morphogenetic protein 2 (BMP2), Runx2/Cbfa1, Msx2, and osteocalcin. In these cells, activation of Wnt/β-catenin signaling was evidenced by the translocation of β-catenin into the nucleus and the increase in the expression of direct target genes as cyclin D1, axin 2, and VCAN/versican. Addition of calcitriol to HP medium (HP + CTR) further increased calcification and also enhanced the expression of osteogenic factors together with a significant elevation of nuclear β-catenin levels and the expression of cyclin D1, axin 2, and VCAN. By contrast, the addition of paricalcitol (HP + PC) not only reduced calcification but also downregulated the expression of BMP2 and other osteoblastic phenotype markers as well as the levels of nuclear β-catenin and the expression of its target genes. The role of Wnt/β-catenin on phosphate- and calcitriol-induced calcification was further demonstrated by the inhibition of calcification after addition of Dickkopf-related protein 1 (DKK-1), a specific natural antagonist of the Wnt/β-catenin signaling pathway. In conclusion, the differential effect of calcitriol and paricalcitol on vascular calcification appears to be mediated by a distinct regulation of the BMP and Wnt/β-catenin signaling pathways

Nuclear Translocation of b-Catenin during Mesenchymal Stem Cells Differentiation into Hepatocytes Is Associated with a Tumoral Phenotype

Wnt/b-catenin pathway controls biochemical processes related to cell differentiation. In committed cells the alteration of this pathway has been associated with tumors as hepatocellular carcinoma or hepatoblastoma. The present study evaluated the role of Wnt/b-catenin activation during human mesenchymal stem cells differentiation into hepatocytes. The differentiation to hepatocytes was achieved by the addition of two different conditioned media. In one of them, b-catenin nuclear translocation, up-regulation of genes related to the Wnt/b-catenin pathway, such as Lrp5 and Fzd3, as well as the oncogenes c-myc and p53 were observed. While in the other protocol there was a Wnt/b-catenin inactivation. Hepatocytes with nuclear translocation of b-catenin also had abnormal cellular proliferation, and expressed membrane proteins involved in hepatocellular carcinoma, metastatic behavior and cancer stem cells. Further, these cells had also increased auto-renewal capability as shown in spheroids formation assay. Comparison of both differentiation protocols by 2D-DIGE proteomic analysis revealed differential expression of 11 proteins with altered expression in hepatocellular carcinoma. Cathepsin B and D, adenine phosphoribosyltransferase, triosephosphate isomerase, inorganic pyrophosphatase, peptidyl-prolyl cis-trans isomerase A or lactate dehydrogenase b-chain were up-regulated only with the protocol associated with Wnt signaling activation while other proteins involved in tumor suppression, such as transgelin or tropomyosin b-chain were downregulated in this protocol. In conclusion, our results suggest that activation of the Wnt/b-catenin pathway during human mesenchymal stem cells differentiation into hepatocytes is associated with a tumoral phenotyp

Evaluación del impacto del perfil del alumnado en la valoración de la actividad docente del profesorado

En este proyecto se analiza el perfil de los estudiantes de primer curso en tres Grados (Química, Biología y Óptica-Optometría) de las Facultades de Ciencias de la UCM, detectando las carencias que presentan los estudiantes en una materia básica como la Química. Se comparan los resultados con los obtenidos en el curso académico 2016-2017. Asimismo se analiza la relación del perfil del alumnado con la valoración de la actividad docente del profesorado que realizan los estudiantes dentro del programa DOCENTIA

Procaine Inhibits Osteo/Odontogenesis through Wnt/β-Catenin Inactivation

Introduction Periodontitis is a complex pathology characterized by the loss of alveolar bone. The causes and the mechanisms that promote this bone resorption still remain unknown. The knowledge of the critical regulators involved in the alteration of alveolar bone homeostasis is of great importance for developing molecular therapies. Procaine is an anesthetic drug with demethylant properties, mainly used by dentists in oral surgeries. The inhibitor role of Wnt signaling of procaine was described in vitro in colon cancer cells. Methods In this work we evaluated the role of procaine (1 uM) in osteo/odontogenesis of rat bone marrow mesenchymal stem cells. Similarly, the mechanisms whereby procaine achieves these effects were also studied. Results Procaine administration led to a drastic decrease of calcium content, alkaline phosphatase activity, alizarin red staining and an increase in the expression of Matrix Gla Protein. With respect to osteo/odontogenic markers, procaine decreased early and mature osteo/odontogenic markers. In parallel, procaine inhibited canonical Wnt/β-catenin pathway, observing a loss of nuclear β-catenin, a decrease in Lrp5 and Frizzled 3, a significant increase of sclerostin and Gsk3β and an increase of phosphorylated β-catenin. The combination of osteo/ odontogenic stimuli and Lithium Chloride decreased mRNA expression of Gsk3β, recovered by Procaine. Furthermore it was proved that Procaine alone dose dependently increases the expression of Gsk3β and β-catenin phosphorylation. These effects of procaine were also observed on mature osteoblast. Interestingly, at this concentration of procaine no demethylant effects were observed. PLO

Artificial Modifications of the Coast In Response to the \u3ci\u3eDeepwater Horizon\u3c/i\u3e Oil Spill: Quick Solutions or Long-Term Liabilities?

The Deepwater Horizon oil spill threatened many coastal ecosystems in the Gulf of Mexico during the spring and summer of 2010. Mitigation strategies included the construction of barrier sand berms, the restriction or blocking of inlets, and the diversion of freshwater from rivers to the coastal marshes and into the ocean, in order to flush away the oil, on the premise that these measures could reduce the quantity of oil reaching sensitive coastal environments such as wetlands or estuaries. These projects result in changes to the ecosystems that they were intended to protect. Long-term effects include alterations of the hydrological and ecological characteristics of estuaries, changes in sediment transport along the coastal barrier islands, the loss of sand resources, and adverse impacts to benthic and pelagic organisms. Although there are no easy solutions for minimizing the impacts of the Deepwater Horizon disaster on coastal ecosystems, we recommend that federal, state, and local agencies return to the strategic use of long-term restoration plans for this region

Engineering periodic dinuclear lanthanide-directed networks featuring tunable energy level alignment and magnetic anisotropy by metal exchange

The design of lanthanide multinuclear networks is an emerging field of research due to the potential of such materials for nanomagnetism, spintronics, and quantum information. Therefore, controlling their electronic and magnetic properties is of paramount importance to tailor the envisioned functionalities. In this work, a multidisciplinary study is presented combining scanning tunneling microscopy, scanning tunneling spectroscopy, X-ray absorption spectroscopy, X-ray linear dichroism, X-ray magnetic circular dichroism, density functional theory, and multiplet calculations, about the supramolecular assembly, electronic and magnetic properties of periodic dinuclear 2D networks based on lanthanide-pyridyl interactions on Au(111). Er- and Dy-directed assemblies feature identical structural architectures stabilized by metal–organic coordination. Notably, despite exhibiting the same +3 oxidation state, there is a shift of the energy level alignment of the unoccupied molecular orbitals between Er- and Dy-directed networks. In addition, there is a reorientation of the easy axis of magnetization and an increment of the magnetic anisotropy when the metallic center is changed from Er to Dy. Thus, the results show that it is feasible to tune the energy level alignment and magnetic anisotropy of a lanthanide-based metal-organic architecture by metal exchange, while preserving the network desig