Maribel Grande

Genomic microarray in fetuses with increased nuchal translucency and normal karyotype: a systematic review and meta‐analysis

To estimate the incremental yield of detecting copy number variants (CNVs) by genomic microarray over karyotyping in fetuses with increased nuchal translucency (NT) diagnosed by first‐trimester ultrasound.

Pattern of Kvβ Subunit Expression in Macrophages Depends upon Proliferation and the Mode of Activation

Voltage-dependent potassium channels (Kv) in leukocytes are involved in the immune response. In bone marrow-derived macrophages (BMDM), proliferation and activation induce delayed rectifier K+ currents, generated by Kv1.3, via transcriptional, translational, and posttranslational controls. Furthermore, modulatory Kvβ subunits coassociate with Kvα subunits, increasing channel diversity and function. In this study we have identified Kvβ subunits in mouse BMDM, studied their regulation during proliferation and activation, and analyzed K+ current parameters influenced by these proteins. BMDM express all isoforms of Kvβ1 (Kvβ1.1, Kvβ1.2, and Kvβ1.3) and Kvβ2 (Kvβ2.1), but not Kvβ4, the alternatively spliced murine Kvβ3 variant. M-CSF-dependent proliferation induced all Kvβ isoforms. However, LPS- and TNF-α-induced activation differentially regulated these subunits. Although LPS increased Kvβ1.3, reduced Kvβ1.2, and maintained Kvβ1.1 mRNA levels constant, TNF-α up-regulated Kvβ1.1, down-regulated Kvβ1.2, and left Kvβ1.3 expression unchanged. Moreover, in contrast to TNF-α, M-CSF- and LPS- up-regulated Kvβ2.1. K+ currents from M-CSF- and LPS-stimulated BMDM exhibited faster inactivation, whereas TNF-α increased τ values. Although in M-CSF-stimulated cells the half-inactivation voltage shifted to more positive potentials, the incubation with LPS and TNF-α resulted in a hyperpolarizing displacement similar to that in resting BMDM. Furthermore, activation time constants of K+ currents and the kinetics of the tail currents were different depending upon the mode of activation. Our results indicate that differential Kvβ expression modifies the electrical properties of Kv in BMDM, dependent upon proliferation and the mode of activation. This could determine physiologically appropriate surface channel complexes, allowing for greater flexibility in the precise regulation of the immune response.

The effect of maternal age on chromosomal anomaly rate and spectrum in recurrent miscarriage

STUDY QUESTION Is there any effect of maternal age on chromosomal anomaly rate and spectrum in recurrent miscarriage? SUMMARY ANSWER There was no significant difference in the chromosome abnormality rate between sporadic and recurrent miscarriage but the chromosome abnormality rate increased significantly with maternal age. WHAT IS KNOWN ALREADY About 50-70% of non-recurrent miscarriages occur because of a chromosomal anomaly, but no agreement about the effect of either maternal age or the number of previous miscarriages on the chromosomal anomaly rate has been reached. STUDY DESIGN, SIZE, DURATION A retrospective cohort of 353 miscarriages successfully karyotyped in the same center between 2002 and 2011, grouped according to the number of miscarriages and maternal age. PARTICIPANTS/MATERIALS, SETTING, METHODS Among the 353 women, 153 were below 35 years (73 with sporadic, 48 with two and 32 with recurrent miscarriage) and 200 were 35 years or more (81 with sporadic, 55 with two and 64 with recurrent miscarriage). The chromosomal anomaly rate and the anomaly spectrum were compared between sporadic and recurrent miscarriage, within the two maternal age groups, using the chi-square test and the Bonferroni correction for all the P-values. Risk of chromosomal anomaly was estimated for maternal age, number of miscarriages and previous live births by multivariate binary logistic regression analysis. MAIN RESULTS AND THE ROLE OF CHANCE Sporadic and recurrent miscarriage did not show significantly different chromosomal anomaly rates (68 versus 60%) and maternal age was the only statistically significant predictor of the chromosomal anomaly risk we identified. Some trends were observed in the chromosomal anomaly spectrum when sporadic was compared with recurrent miscarriage: recurrent miscarriage exhibited a decrease in viable trisomies (37 versus 11%) and an increase in non-viable trisomies (38 versus 57%) in women >35 years, together with an increase in unbalanced structural anomalies (4.9 versus 29%) in younger women. LIMITATION, REASONS FOR CAUTION The mixed origin of our study population, and the limited number of recurrent miscarriages, particularly in the younger group, limits statistical power to detect differences. WIDER IMPLICATIONS OF THE FINDINGS The most commonly observed chromosomal anomaly type in recurrent miscarriage depends on maternal age: non-viable autosomal trisomies in older women and unbalanced structural anomalies in younger women. When a chromosomal anomaly is identified as the cause of miscarriage, additional maternal evaluation may be avoided. STUDY FUNDING/COMPETING INTERESTS No competing interests declared.

KCNQ1/KCNE1 channels during germ-cell differentiation in the rat: Expression associated with testis pathologies

KCNQ1/KCNE1 channels are responsible for the Jervell–Lange–Nielsen cardiac syndrome, which is also characterized by congenital deafness. KCNQ1/KCNE1 is crucial for K+ transport in the inner ear. We show that KCNQ1 and KCNE1 are associated in testis and that their expression is closely regulated during development. Both genes were expressed in undifferentiated germ cells in 21‐day‐old rats and mostly confined to basal immature germ cells in adulthood. Leydig and Sertoli cells were negative. KCNQ1 and KCNE1 were also studied in various germ‐cell pathologies. First, in spontaneous unilateral rat testis atrophy, hematoxylin–eosin analysis revealed massive germ‐cell aplasia with only Sertoli cells and groups of interstitial Leydig cells. In these samples, KCNQ1 and KCNE1 were not expressed. In human seminoma samples characterized by a proliferation of undifferentiated germ cells, KCNQ1/KCNE1 protein levels were higher than in healthy samples. Our results demonstrate that the expression of KCNQ1 and KCNE1 is associated with early stages of spermatogenesis and with the presence of undifferentiated healthy or neoplastic germ cells. The presence of a K+ rich‐fluid in the seminiferous tubule suggests that KCNQ1/KCNE1 is involved in K+ transport, probably during germ‐cell development.

Activation of Srk1 by the Mitogen-activated Protein Kinase Sty1/Spc1 Precedes Its Dissociation from the Kinase and Signals Its Degradation

Control of cell cycle progression by stress-activated protein kinases (SAPKs) is essential for cell adaptation to extracellular stimuli. The Schizosaccharomyces pombe SAPK Sty1/Spc1 orchestrates general changes in gene expression in response to diverse forms of cytotoxic stress. Here we show that Sty1/Spc1 is bound to its target, the Srk1 kinase, when the signaling pathway is inactive. In response to stress, Sty1/Spc1 phosphorylates Srk1 at threonine 463 of the regulatory domain, inducing both activation of Srk1 kinase, which negatively regulates cell cycle progression by inhibiting Cdc25, and dissociation of Srk1 from the SAPK, which leads to Srk1 degradation by the proteasome.

Voltage‐dependent K+ channel β subunits in muscle: Differential regulation during postnatal development and myogenesis

Voltage‐dependent potassium channels contribute to the electrical properties of nerve and muscle by affecting action potential shape and duration. The complexity of the currents generated is further enhanced by the presence of accessory β subunits. Here we report that while all Kvβ mRNA isoforms are present in rat brain, muscle tissues express only Kvβ1 (Kvβ1.1–Kvβ1.3) and Kvβ2, but not Kvβ3. Kvβ subunits were close regulated through post‐natal development in brain and striated muscle, as well as during myogenesis in the rat skeletal muscle cell line L6E9. While the alternatively spliced Kvβ mRNA products from Kvβ1 gene were differentially expressed, Kvβ2.1 was associated with myogenesis. These results show that Kvβ genes are strongly regulated in muscle and suggest a physiological role for voltage‐gated K+ channels during development and myotube formation.

Different Kv2.1/Kv9.3 heteromer expression during brain and lung post-natal development in the rat

The Kv2.1/Kv9.3 heteromer generates an O2 sensitive potassium channel and induces a slow deactivation that has important consequences for brain and lung physiology. We examined the developmental regulation of Kv2.1 and Kv9.3 mRNAs in brain and lung. Both genes followed parallel expression patterns in brain, increasing progressively through post-natal life. In lung, however, the expression of the two genes followed opposite trends: Kv2.1 transcripts decreased, while Kv9.3 mRNA increased. The Kv9.3/Kv2.1 ratio shows that while in brain the expression of both genes followed a similar pattern, the relative abundance of Kv9.3 increased steadily through post-natal life in lung. Furthermore, there is selective regulation of gene expression during the suckling-weaning transition. Our results suggest that different Kv9.3/Kv2.1 ratios could have physiological implications in both organs during postnatal development, and that diet composition and selective tissue-specific insulin regulation modulate the expression of Kv2.1 and Kv9.3.ResumenEl heterómero Kv2.1/Kv9.3 genera un canal de potasio sensible al O2 e induce una inactivación lenta que tiene consecuencias importantes en la fisiologiá cerebral y pulmonar. Se examina la regulación durante el desarrollo de los mRNA de Kv2.1 y Kv9.3 en cerebro y pulmón. Los dos genes presentan una expresión paralela en cerebro, incrementando progresivamente durante la vida post-natal. Sin embargo, la expresión de los dos genes sigue patrones opuestos en pulmón. Así, mientras que dismuye la expresión de Kv2.1, se incrementa la de Kv9.3. La relación Kv9.3/Kv2.1 demuestra que mientras en cerebro la expresión de los dos genes sigue un patrón similar, la abundancia relativa de Kv9.3 aumenta durante la etapa post-natal en pulmón. Estos resultados indican que una relación diferente entre Kv9.3/Kv2.1 puede tener implicaciones fisiológicas en ambos órganos durante el desarrollo post-natal. Además, existe una regulación selectiva de la expresión génica durante la transición del destete. Nuestros datos sugieren que tanto la composición de la dieta como una regulación selectiva específica de cada tejido condicionan la expresión de Kv2.1 y Kv9.3.

Crosstalk between Nap1 protein and Cds1 checkpoint kinase to maintain chromatin integrity.

The nucleosome assembly protein Nap1 has been implicated in various cellular functions such as histone shuttling into the nucleus, nucleosome assembly, chromatin remodelling, transcriptional control and cell-cycle regulation in Saccharomyces cerevisiae. In Schizosaccharomyces pombe nap1 null mutant cells are viable but they showed a delay in the onset of mitosis which is rescued by the absence of the replication Cds1 checkpoint kinase. In contrast, the absence of the DNA-damage Chk1 checkpoint kinase is unable to rescue the delay. Moreover, the double nap1 cds1 mutant cells lose viability and cells show positive H2AX phosphorylation, suggesting that the viability of nap1-deleted cells is due to the Cds1 kinase. We also show that overexpression of Nap1 protein blocks the cell cycle in G1 phase.

Nuchal translucency thickness in the prediction of unbalanced translocations

The aim of this study was to assess the role of nuchal translucency (NT) in the prediction of unbalanced translocation in offspring of couples in which one of the parents is a balanced translocation carrier.

Genomic Microarray in Fetuses with Early Growth Restriction: A Multicenter Study

Background: Little information is available about the risk of microdeletion and microduplication syndromes in fetal growth restriction (FGR) with a normal karyotype. Objective: To assess the incremental yield of genomic microarray over conventional karyotyping in fetuses with early growth restriction. Study Design: Genomic microarray was prospectively performed in fetuses with early growth restriction defined as a fetal weight below the 3rd percentile estimated before 32 weeks of pregnancy, and a normal quantitative fluorescent polymerase chain reaction result. The incremental yield of genomic microarray was defined by the rate of fetuses presenting with a pathogenic copy number variant below 10 Mb. Results: Among 133 fetuses with early FGR, a 6.8% (95% CI: 2.5-11.0) incremental yield of genomic microarray over karyotyping was observed. This incremental yield was 4.8% (95% CI: 0.2-9.3) in isolated FGR, 10% (95% CI: 0-20.7) in FGR with nonstructural anomalies, and 10.5% (95% CI: 0-24.3) in FGR with structural anomalies. Conclusion: Our multicenter study reveals that 6.8% of fetuses with early growth restriction present with submicroscopic anomalies after common aneuploidies were excluded. Even when FGR is observed as an isolated finding, genomic microarray analysis should be considered after or instead of karyotyping, due to its 4.8% incremental yield.