Human peritoneal mesothelial cell death induced by high-glucose hypertonic solution involves Ca2+ and Na+ ions and oxidative stress with the participation of PKC/NOX2 and PI3K/Akt pathways

Indexación: Web of Science; Scopus.Chronic peritoneal dialysis (PD) therapy is equally efficient as hemodialysis while providing greater patient comfort and mobility. Therefore, PD is the treatment of choice for several types of renal patients. During PD, a high-glucose hyperosmotic (HGH) solution is administered into the peritoneal cavity to generate an osmotic gradient that promotes water and solutes transport from peritoneal blood to the dialysis solution. Unfortunately, PD has been associated with a loss of peritoneal viability and function through the generation of a severe inflammatory state that induces human peritoneal mesothelial cell (HPMC) death. Despite this deleterious effect, the precise molecular mechanism of HPMC death as induced by HGH solutions is far from being understood. Therefore, the aim of this study was to explore the pathways involved in HGH solution-induced HPMC death. HGH-induced HPMC death included influxes of intracellular Ca2+ and Na+. Furthermore, HGH-induced HPMC death was inhibited by antioxidant and reducing agents. In line with this, HPMC death was induced solely by increased oxidative stress. In addition to this, the cPKC/NOX2 and PI3K/Akt intracellular signaling pathways also participated in HGH-induced HPMC death. The participation of PI3K/Akt intracellular is in agreement with previously shown in rat PMC apoptosis. These findings contribute toward fully elucidating the underlying molecular mechanism mediating peritoneal mesothelial cell death induced by high-glucose solutions during peritoneal dialysis.https://www.frontiersin.org/articles/10.3389/fphys.2017.00379/ful

Immune DNA signature of T-cell infiltration in breast tumor exomes.

Tumor infiltrating lymphocytes (TILs) have been associated with favorable prognosis in multiple tumor types. The Cancer Genome Atlas (TCGA) represents the largest collection of cancer molecular data, but lacks detailed information about the immune environment. Here, we show that exome reads mapping to the complementarity-determining-region 3 (CDR3) of mature T-cell receptor beta (TCRB) can be used as an immune DNA (iDNA) signature. Specifically, we propose a method to identify CDR3 reads in a breast tumor exome and validate it using deep TCRB sequencing. In 1,078 TCGA breast cancer exomes, the fraction of CDR3 reads was associated with TILs fraction, tumor purity, adaptive immunity gene expression signatures and improved survival in Her2+ patients. Only 2/839 TCRB clonotypes were shared between patients and none associated with a specific HLA allele or somatic driver mutations. The iDNA biomarker enriches the comprehensive dataset collected through TCGA, revealing associations with other molecular features and clinical outcomes

Developmental regulation of the expression of sodium currents in Xenopus primary neurons

The electrophysiological properties of neurons are determined by the expression of defined complements of ion channels. Nonetheless, the regulation mechanisms of the expression of neuronal ion channels are poorly understood, due in part to the diversity of neuron subtypes. We explored the expression of voltage-gated currents of Xenopus primary spinal neurons unequivocally identified by means of single-cell RT-PCR. We found that identified spinal neurons exhibit heterogeneity in the temporal appearance of voltage-gated currents. Nevertheless, all neurons progress to similar functional phenotypes. A physiological feature is the onset and increase of the expression of sodium currents. To understand the mechanisms underlying this process, we studied the effect of a dominant negative form of the transcriptional silencer REST/NRSF and found that it associates to an increase in the density of sodium currents. This observation is compatible with a role of this factor in the regulation of gene expression in neurons. These experiments constitute a proof of principle for the feasibility of analyzing molecular mechanisms of the regulation of ion channel genes during early neuronal development and provide direct evidence of the role of REST/NRSF in the control of neuronal sodium channel expression

Endovenous laser and echo-guided foam ablation in great saphenous vein reflux: one-year follow-up results

BackgroundGreat saphenous vein (GSV) reflux is the most frequent form of venous insufficiency in symptomatic patients and is commonly responsible for varicose veins of the lower extremity. This non-randomized prospective controlled study was designed to test the hypothesis that 1) endovenous laser treatment is more effective than foam sclerotherapy in the closure of the refluxing GSV (as measured by degree of great saphenous vein reflux and venous clinical severity score changes) and 2) to record the associated complications of echo-guided endovenous chemical ablation with foam and endovenous laser therapy for the treatment of great saphenous vein reflux and to further identify risk factors associated with treatment failure.MethodsBetween January 1, 2006 and June 25, 2006, patients seeking treatment of varicose veins at a private practice of vascular medicine were assessed for the study. Inclusion criteria were: 1) presence of great saphenous vein reflux and 2) C2-6, Epr, A s, according to the CEAP classification. The selected patients consented into the study and were allowed to choose between foam (53 patients) or laser (45 patients) treatment. Duplex examinations were performed prior to treatment and at seven and 14 days, four weeks, six months, and one year after treatment. Venous clinical severity score was assessed pre-treatment and at one year post-procedure.ResultsThe cohorts showed no statistically significant differences in age, sex, clinical and anatomical presentation, great saphenous vein diameter, and venous clinical severity score before the treatments. After one year follow up, occlusion of the great saphenous vein was confirmed in 93.4% (42/45) of limbs studied in the laser group and 77.4% (41/53) of limbs in the foam group (P < .0465). Venous clinical severity score significantly improved in both groups (P < .0001). Procedure associated pain was higher in the laser group (P < .0082). Induration, phlebitis, and ecchymosis were the most common complications. Logistical regression and subgroups analysis shown that a larger great saphenous vein diameter measured before treatment was associated with treatment failure in the foam (odds ratio 1.68, 95% CI 1.24-2.27, P < .0008) and in the laser group (odds ratio 1.91, 95% CI 1.02-3.59, P < .0428). A 90% treatment success is predicted for veins <6.5 mm in the foam group versus veins <12 mm in the laser group.ConclusionsOverall, endovenous laser ablation achieved higher occlusion rates than echo-guided chemical ablation with foam after one year follow-up. Matching the patient to the technique based on great saphenous vein diameter measured before treatment may assist in boosting the treatment success rate to >90%. A larger patient cohort followed and compared over a longer period of time would be required to confirm these findings

Modal gating in neuronal and skeletal muscle ryanodine-sensitive Ca2+ release channels

The bursting behavior of ryanodine-sensitive single Ca2+ release channels present in chicken cerebellum endoplasmic reticulum (ER), rat hippocampus ER, and frog and rabbit skeletal muscle sarcoplasmic reticulum was established. Unconditional dwell time distributions fitted by the maximum likelihood method reveal at least three open and closed exponential components. Trains of low open probability (P(o)) bursts were interspersed with trains of high P0, bursts (≤0.8) in all the ryanodine receptor isotypes tested. The gating kinetics of the Ca2+ release channels were defined in long recordings by analyzing burst sequences and gamma distributions of average intraburst open (T(o)) and closed times (T(e)). The gamma distributions of T(o) had two gamma components, suggesting the existence of two distinct burst types. In contrast, the gamma distributions of T(e) had only one component. The correlation between consecutive burst pairs was defined in terms of T(o) and then statistically tested b

Repressor element-1 silencing transcription/neuron-restrictive silencer factor is required for neural sodium channel expression during development of Xenopus

The ability of neurons to fire rapid action potential relies on the expression of voltage-gated sodium channels; the onset of the transcription of genes that encode these channels occurs during early neuronal development. The factors that direct and regulate the specific expression of ion channels are not well understood. Repressor element-1 silencing transcription/ neuron-restrictive silencer factor (REST/NRSF) is a transcriptional regulator characterized as a repressor of the expression of NaV1.2, the gene encoding the voltage-gated sodium channel most abundantly expressed in the CNS, as well as of the expression of numerous other neuronal genes. In mammals, REST/NRSF is expressed mostly in non-neural cell types and immature neurons, and it is downregulated on neural maturation. To understand the mechanisms that govern sodium channel gene transcription and to explore the role of REST/NRSF in vivo, we inhibited REST/NRSF action in developing Xenopus laevis embryos by means of a domin

Immune DNA signature of T-cell infiltration in breast tumor exomes.

Tumor infiltrating lymphocytes (TILs) have been associated with favorable prognosis in multiple tumor types. The Cancer Genome Atlas (TCGA) represents the largest collection of cancer molecular data, but lacks detailed information about the immune environment. Here, we show that exome reads mapping to the complementarity-determining-region 3 (CDR3) of mature T-cell receptor beta (TCRB) can be used as an immune DNA (iDNA) signature. Specifically, we propose a method to identify CDR3 reads in a breast tumor exome and validate it using deep TCRB sequencing. In 1,078 TCGA breast cancer exomes, the fraction of CDR3 reads was associated with TILs fraction, tumor purity, adaptive immunity gene expression signatures and improved survival in Her2+ patients. Only 2/839 TCRB clonotypes were shared between patients and none associated with a specific HLA allele or somatic driver mutations. The iDNA biomarker enriches the comprehensive dataset collected through TCGA, revealing associations with other molecular features and clinical outcomes

L-type calcium channel β subunit modulates angiotensin II responses in cardiomyocytes

Angiotensin II regulation of L-type calcium currents in cardiac muscle is controversial and the underlying signaling events are not completely understood. Moreover, the possible role of auxiliary subunit composition of the channels in Angiotensin II modulation of L-type calcium channels has not yet been explored. In this work we study the role of CaVβ subunits and the intracellular signaling responsible for L-type calcium current modulation by Angiotensin II. In cardiomyocytes, Angiotensin II exposure induces rapid inhibition of L-type current with a magnitude that is correlated with the rate of current inactivation. Semi-quantitative PCR of cardiomyocytes at different days of culture reveals changes in the CaVβ subunits expression pattern that are correlated with the rate of current inactivation and with Angiotensin II effect. Overexpression of individual β subunits in heterologous systems reveals that the magnitude of Angiotensin II inhibition is dependent on the CaVβ subunit isofor

Chromosomal Instability in Mouse Embryonic Fibroblasts Null for the Transcriptional Co-Repressor Ski

Artículo de publicación ISISki is a transcriptional regulator that has been considered an oncoprotein given its ability to induce oncogenic transformation in avian model systems. However, studies in mouse and in some human tumor cells have also indicated a tumor suppressor activity for this protein. We found that Ski-/- mouse embryo fibroblasts exhibit high levels of genome instability, namely aneuploidy, consistent with a tumor suppressor function for Ski. Time-lapse microscopy revealed lagging chromosomes and chromatin/chromosome bridges as the major cause of micronuclei (MN) formation and the subsequent aneuploidy. Although these cells arrested in mitosis after treatment with spindle disrupting drugs and exhibited a delayed metaphase/anaphase transition, spindle assembly checkpoint (SAC) was not sufficient to prevent chromosome missegregation, consistent with a weakened SAC. Our in vivo analysis also showed dynamic metaphase plate rearrangements with switches in polarity in cells arrested in metaphase. Importantly, after ectopic expression of Ski the cells that displayed this metaphase arrest died directly during metaphase or after aberrant cell division, relating SAC activation and mitotic cell death. This increased susceptibility to undergo mitosis-associated cell death reduced the number of MN-containing cells. The presented data support a new role for Ski in the mitotic process and in maintenance of genetic stability, providing insights into the mechanism of tumor suppression mediated by this protein.US Public Health Service, National Cancer Institute CA42573 T32-CA009176 Vicerrectoria de Investigacion y Desarrollo (VID) from Universidad de Chile 107/11-2 Fondo de Financiamiento de Centros de Excelencia en Investigacion (FONDAP) 1501000