Loss of endothelial barrier integrity in mice with conditional ablation of podocalyxin (Podxl) in endothelial cells

26 p.-6 fig.Podocalyxin (Podxl) has an essential role in the development and function of the kidney glomerular filtration barrier. It is also expressed by vascular endothelia but perinatal lethality of podxl−/− mice has precluded understanding of its function in adult vascular endothelial cells (ECs). In this work, we show that conditional knockout mice with deletion of Podxl restricted to the vascular endothelium grow normally but most die spontaneously around three months of age. Histological analysis showed a nonspecific inflammatory infiltrate within the vessel wall frequently associated with degenerative changes, and involving vessels of different caliber in one or more organs. Podxl-deficient lung EC cultures exhibit increased permeability to dextran and macrophage transmigration. After thrombin stimulation, ECs lacking Podxl showed delayed recovery of VE-cadherin cell contacts, persistence of F-actin stress fibers, and sustained phosphorylation of the ERM complex and activation of RhoA, suggesting a failure in endothelial barrier stabilization. The results suggest that Podxl has an essential role in the regulation of endothelial permeability by influencing the mechanisms involved in the restoration of endothelial barrier integrity after injury.This work was supported by grants SAF2007-61701 and BFU2010-15237 from the Secretaría de Estado de Investigación, Desarrollo e Innovación, and grant PIE 201020E018 from CSIC. Angélica Horrillo and Gracia Porras were supported by contracts from CIBER de Enfermedades Raras (CIBERER), an initiative of the Spanish Health Institute Carlos III (ISCIII).Peer reviewe

Healthy aging and late-life depression in Europe: Does migration matter?

Background: There is limited research examining the impact of risk and protective factors on late-life depression using large population-based datasets, particularly those examining differences among older migrants and non-migrants in Europe countries. Thus, the first aim was to analyze differences between migrants and non-migrants regarding socioeconomic status, depression, multimorbidity, healthy aging, and lifestyle behaviors. The second aim was to examine the impact of healthy aging on late-life depression in older migrants compared to their counterparts without a history of international migration in extensive and harmonized data from different population-based cohort studies. Materials and methods: We analyzed cross-sectional, predominantly nationally representative, community-based data from European participants in the Aging Trajectories of Health: Longitudinal Opportunities and Synergies (ATHLOS) cohort. The descriptive analyses included sociodemographic variables, somatic comorbidities, multimorbidity, healthy aging, and lifestyle behaviors according to migration status. The effects of these variables on late-life depression were examined in a multivariate logistic regression model, including migration status and years since migration as predictors. Results: Data of 122,571 individuals aged = 50 years were analyzed, of which 11,799 (9.60%) were migrants. The descriptive analyses indicated that compared to non-migrants, migrants showed a higher prevalence of diabetes (25.6%), hypertension (38.0%), coronary artery disease (49.4%), stroke (4.9%), and depression (31.1%). Healthy aging was also better in non-migrants (51.7; SD = 9.7) than in migrants (39.6; SD = 18.2). The results of the logistic regression showed that migration status [OR = 1.231 (CIs: 0.914–1.547)] and increased number of years since migration in the host country [OR = 0.003 (CIs: 0.001–0.005)] were associated with greater levels of depressive symptoms. Concerning health variables, multimorbidity was associated with higher levels of depressive symptoms [OR = 0.244 (CIs: 0.211–0.278)], whereas better healthy aging was associated with fewer depressive symptoms [OR = -0.100 (CIs: -0.102 to -0.098)]. The interaction between migration and healthy aging status was also significant [OR. = -0.019 (CIs: -0.025 to -0.014)]. Conclusion: Migrants reported higher risks for worse health outcomes compared to non-migrants. Significantly, worse healthy aging was associated with a greater risk of depressive symptoms in migrants than in non-migrants. Shedding light on migration and aging processes is essential for promoting a cross-cultural understanding of late-life depression in EuropeDF’s work was supported by grant 2017 SGR 622 (GRBIO) administrated by the Departament d’Economia i Coneixement de la Generalitat de Catalunya (Spain), by Marsden grant E2987-3648 administrated by the Royal Society of New Zealand, and by the Ministerio de Ciencia e Innovación (Spain) [PID2019-104830RB-I00/DOI (AEI): 10.13039/501100011033]Peer ReviewedPostprint (published version

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Cellular metabolite distribution and the control of gluconeogenesis in the perfused isolated rat liver

Glucose production was measured in isolated rat livers perfused with 100 ml of blood-free recirculating medium. The gluconeogenic rate using l-alanine as substrate was only 55% of that obtained with l-lactate. The steady-state concentration of gluconeogenic and tricarboxylic acid cycle intermediates were measured in freeze clamped biopsies. Livers perfused with l-lactate displayed higher concentrations of malate, α-glycerophosphate and β-hydroxybutyrate probably as a result of a higher state of reduction of the nicotinamide system. Hexose-phosphate intermediates were also increased when l-lactate was the substrate. Phosphoenolpyruvate and 3-phosphoglycerate were considerably elevated when l-alanine was the glucose precursor. Livers perfused with l-lactate displayed higher cytosolic concentration of all the tricarboxylic acid cycle intermediates except oxaloacetate while glutamate was slightly and aspartare considerably higher when alanine was the substrate. In the mitochondrial compartment the pattern of distribution tended to be the opposite; that is, livers perfused with l-lactate showed lower concentrations of all the intermediates except α-ketoglutarate. The mitochondrial: cytosolic metabolite gradients of all the intermediates whose distribution was studied were higher in livers perfused with l-alanine. The relevance of these findings to the observed differences in the gluconeogenic fluxes are discussed.This work has been supported in part by a Grant-in-aid from Lilly Indiana and a research grant (612/9) from the Spanish Advisory Commission for the Development of Research.Peer reviewe

Guanosine Triphosphate Dependent Enzymic Binding of Aminoacyl Transfer Ribonucleic Acid to Yeast Ribosomes

The binding of phenylalanyl-tRNA to purified yeast ribosomes at low magnesium concentrations is dependent upon one of the yeast supernatant transfer factors (factor A). This reaction requires GTP. The GTP analogue guanylyl methylene diphosphonate cannot be substituted for GTP but it acts as a good inhibitor. After incubation of the ribosomes with phenylalanyl-tRNA, factor A and GTP practically no compound other than phenylalanyl-tRNA itself is found linked to the ribosomes. In addition to this enzymic type of binding, phenylalanyl-tRNA is also bound to yeast ribosomes in the absence of factor A and GTP provided that the magnesium concentration is increased to about 20 mM. This non-enzymic binding is effectively inhibited by deacylated tRNA and this inhibition is prevented if factor A and GTP are included in the incubation mixtures. The binding of N-acetylphenylalanyl-tRNA to yeast ribosomes also requires GTP, and is dependent upon factor(s) other than the amino acid transfer factors, which are bound to the ribosomes.Peer reviewe

Glucagon effect on rat liver protein synthesis in vivo

The in vivo effect of glucagon administration on hepatic polyribosomal profiles has been studied. Glucagon did not change significantly total, free or bound polyribosomal fractions 30-45 minutes after its administration. The combined administration of glucagon plus antiinsulin serum failed to show any significant effect of glucagon over the antiinsulin serum treated control. Glucagon increased valine production in the perfused isolated liver. These results suggest that the well known amino acid catabolic action of glucagon may be preferentially mediated through an increased proteolysis. Since it is known that glucagon increases considerably in vivo the liver cyclic AMP levels then its lack of effect on polyribosomal profiles might indicate that the postulated role for the cyclic nucleotide on liver protein synthesis must be taken cautiously.This work has been supported by a Grant-in-aid from Lilly Indiana S.A. and a research grant (612/g) from Fondo Nacional para el Desarrollo de la Investigación.Peer reviewe

Acute Effects of Ethanol in the Control of Protein Synthesis in Isolated Rat Liver Cells

The acute effect of ethanol on hepatic protein synthesis is a rather controversial issue. In view of the conflicting reports on this subject, the effect of ethanol on protein labeling from l-[3H]valine in isolated liver cells was studied under a variety of experimental conditions. When tracer doses of the isotope were utilized, ethanol consistently decreased the rate of protein labeling, regardless of the metabolic conditions of the cells. This inhibition was not prevented by doses of 4-methylpyrazole large enough to abolish all the characteristic metabolic effects of ethanol, and it was not related to perturbations on the rates of l-valine transport and/or proteolysis. When ethanol was tested in the presence of saturating doses of l-[3H]valine no effect on protein labeling was observed. These observations suggest that the ethanol effect in decreasing protein labelling from tracer doses of the radioactive precursor does not reflect variations in the rate of protein synthesis but reflects changes in the specific activity of the precursor. These changes probably are secondary to variations in the dimensions of the amino acid pool utilized for protein synthesis. Even though it showed a lack of effect when tested alone, in the presence of saturating doses of the radioactive precursor ethanol inhibited the stimulatory effects on protein synthesis mediated by glucose and several gluconeogenic substrates. This effect of ethanol was not prevented by inhibitors of alcohol dehydrogenase, indicating that a shift of the NAD system to a more reduced state is not the mediator of its action. It is suggested that ethanol probably acted by changing the steady-state levels of some common effector(s) generated from the metabolism of all these fuels or else by preventing the inactivation of a translational repressor. © 1983.This work has been supported in parts by grants from the Comisión Asesora para el Desarrollo Científico y Técnico, Fondo de Investigaciones Sanitarias de la Seguridad Social, and Laboratory Essex España.Peer reviewe

Glucagon and Insulin Control of Gluconeogenesis in the Perfused Isolated Rat Liver. Effects on Cellular Metabolite Distribution

The metabolic effects of glucagon and glucagon plus insulin on the isolated rat livers perfused with 10 mM sodium L‐lactate as substrate were studied. Glucagon stimulated gluconeogenesis, ketogenesis and ureogenesis at the concentration used of 2.1 nM. The addition of insulin to give a glucagon‐to‐insulin ratio of 0.2 reversed all the glucagon effects. The glucagon enhancement of gluconeogenesis was accompanied by a rise in the cytosolic and mitochondrial state of reduction of the NAD system and a fall in the [ATP]/[ADP] ratio. The analysis of the intermediary metabolite concentrations suggested, as possible sites of glucagon action, the steps between pyruvate and phosphoenolpyruvate as well as the reactions catalyzed by phosphofructokinase and/or fructose bisphosphatase. All the changes in metabolite contents were abolished when insulin was present. Glucagon increased the intramitochondrial concentration of all the metabolites, whose intracellular distribution was calculated. The finding of a significant rise in the calculated intramitochondrial concentration of oxaloacetate points to pyruvate carboxylation as an important site of glucagon interaction with the gluconeogenic pathway. A primary event in the glucagon action redistributing intracellular metabolites seems to be the mitochondrial entry of malate. The possibility is discussed that the changes in metabolite cellular distribution were brought about by the increased cellular state of reduction caused by the hormone.This work has been supported by grants from Lilly Indiana S. A.. Fundación Rodríguez Pascual and Comisión Asesora para el Desarrollo de la Investigación.Peer reviewe

Glucose inhibition of oxygen utilization by isolated rat lung cells

The inhibition of glycolysis by the availability of oxygen was originally described by Pasteur and is a metabolic feature of practically universal occurence. Crabtree [1] described the reverse phenomenon, this is the inhibition of oxygen utilization by glycolysis. This effect, known as Crabtree effect, is rather unusual and so far has been circumscribed mainly, if not exclusively, to rapidly glycolyzing ceils, mostly ~umoral cells. Isolated rat lung cells, which have in common with tumoral cells to display high glycolytic fluxes [2, 3] have also been found to show glucose inhibition of oxygen uptake [3]. The results showed herein are an attempt to characterize this phenomenon.This work was supported in part by grants from Comisión Asesora para el Desarrollo de la Investigación and Essex Espafia S.A.J.P.D. and A.M. are recipients of research fellowships from the Spanish Secretary of Education and Science.Peer reviewe