YY2 in Mouse Preimplantation Embryos and in Embryonic Stem Cells.

Yin Yang 2 encodes a mammalian-specific transcription factor (YY2) that shares high homology in the zinc finger region with both YY1 and REX1/ZFP42, encoded by the Yin Yang 1 and Reduced Expression Protein 1/Zinc Finger Protein 42 gene, respectively. In contrast to the well-established roles of the latter two in gene regulation, X chromosome inactivation and binding to specific transposable elements (TEs), much less is known about YY2, and its presence during mouse preimplantation development has not been described. As it has been reported that mouse embryonic stem cells (mESC) cannot be propagated in the absence of Yy2, the mechanistic understanding of how Yy2 contributes to mESC maintenance remains only very partially characterized. We describe Yy2 expression studies using RT-PCR and staining with a high-affinity polyclonal serum in mouse embryos and mESC. Although YY2 is expressed during preimplantation development, its presence appears dispensable for developmental progress in vitro until formation of the blastocyst. Attenuation of Yy2 levels failed to alter either Zscan4 levels in two-cell embryos or IAP and MERVL levels at later preimplantation stages. In contrast to previous claims that constitutively expressed shRNA against Yy2 in mESC prohibited the propagation of mESC in culture, we obtained colonies generated from mESC with attenuated Yy2 levels. Concomitant with a decreased number of undifferentiated colonies, Yy2-depleted mESC expressed higher levels of Zscan4 but no differences in the expression of TEs or other pluripotency markers including Sox2, Oct4, Nanog and Esrrb were observed. These results confirm the contribution of Yy2 to the maintenance of mouse embryonic stem cells and show the preimplantation expression of YY2. These functions are discussed in relation to mammalian-specific functions of YY1 and REX1.

The effect of abscisic acid chronic treatment on neuroinflammatory markers and memory in a rat model of high-fat diet induced neuroinflammation.

BACKGROUND: Western diet and lifestyle are associated with overweight, obesity, and type 2 diabetes, which, in turn, are correlated with neuroinflammation processes. Exercise and a healthy diet are important in the prevention of these disorders. However, molecules inhibiting neuroinflammation might also be efficacious in the prevention and/or treatment of neurological disorders of inflammatory etiology. The abscisic acid (ABA) is a phytohormone involved in hydric-stress responses. This compound is not only found in plants but also in other organisms, including mammals. In rodents, ABA can play a beneficial role in the regulation of peripheral immune response and insulin action. Thus, we hypothesized that chronic ABA administration might exert a protective effect in a model of neuroinflammation induced by high-fat diet (HFD). METHODS: Male Wistar rats were fed with standard diet or HFD with or without ABA in the drinking water for 12 weeks. Glucose tolerance test and behavioral paradigms were performed to evaluate the peripheral and central effects of treatments. One-Way ANOVA was performed analyzed statistical differences between groups. RESULTS: The HFD induced insulin resistance peripherally and increased the levels of proinflammatory markers in in the brain. We observed that ABA restored glucose tolerance in HFD-fed rats, as expected. In addition, chronic ABA treatment rescued cognitive performance in these animals, while not affecting control diet fed animals. Moreover, it counteracted the changes induced by HFD in the hypothalamus; microglia activations and TNFα mRNA levels. CONCLUSION: These results suggest that ABA might become a new therapeutic molecule improving the neuroinflammatory status and insulin resistance.

The Motor Cortex Is Involved in the Generation of Classically Conditioned Eyelid Responses in Behaving Rabbits.

UNLABELLED: Classical blink conditioning is a well known model for studying neural generation of acquired motor responses. The acquisition of this type of associative learning has been related to many cortical, subcortical, and cerebellar structures. However, until now, no one has studied the motor cortex (MC) and its possible role in classical eyeblink conditioning. We recorded in rabbits the activity of MC neurons during blink conditioning using a delay paradigm. Neurons were identified by their antidromic activation from facial nucleus (FN) or red nucleus (RN). For conditioning, we used a tone as a conditioned stimulus (CS) followed by an air puff as an unconditioned stimulus (US) that coterminated with it. Conditioned responses (CRs) were determined from the electromyographic activity of the orbicularis oculi muscle and/or from eyelid position recorded with the search coil technique. Type A neurons increased their discharge rates across conditioning sessions and reached peak firing during the CS-US interval, while type B cells presented a second peak during US presentation. Both of them project to the FN. Type C cells increased their firing across the CS-US interval, reaching peak values at the time of US presentation, and were activated from the RN. These three types of neurons fired well in advance of the beginning of CRs and changed with them. Reversible inactivation of the MC during conditioning evoked a decrease in learning curves and in the amplitude of CRs, while train stimulation of the MC simulated the profile and kinematics of conditioned blinks. In conclusion, MC neurons are involved in the acquisition and expression of CRs. SIGNIFICANCE STATEMENT: Classical blink conditioning is a popular experimental model for studying neural mechanisms underlying the acquisition of motor skills. The acquisition of this type of associative learning has been related to many cortical, subcortical, and cerebellar structures. However, until now, no one has studied the motor cortex (MC) and its possible role in classical eyeblink conditioning. Here, we report that the firing activities of MC neurons, recorded in behaving rabbits, are related to and preceded the initiation of conditioned blinks. MC neurons were identified as projecting to the red or facial nuclei and encoded the kinematics of conditioned eyelid responses. The timed stimulation of recording sites simulated the profile of conditioned blinks. MC neurons play a role in the acquisition and expression of these acquired motor responses.

In Vivo Chromatin Targets of the Transcription Factor Yin Yang 2 in Trophoblast Stem Cells.

BACKGROUND: Yin Yang 2 (YY2) is a zinc finger protein closely related to the well-characterized Yin Yang 1 (YY1). YY1 is a DNA-binding transcription factor, with defined functions in multiple developmental processes, such as implantation, cell differentiation, X inactivation, imprinting and organogenesis. Yy2 has been treated as a largely immaterial duplication of Yy1, as they share high homology in the Zinc Finger-region and similar if not identical in vitro binding sites. In contrast to these similarities, gene expression alterations in HeLa cells with attenuated levels of either Yy1 or Yy2 were to some extent gene-specific. Moreover, the chromatin binding sites for YY2, except for its association with transposable retroviral elements (RE) and Endogenous Retroviral Elements (ERVs), remain to be identified. As a first step towards defining potential Yy2 functions matching or complementary to Yy1, we considered in vivo DNA binding sites of YY2 in trophoblast stem (TS) cells. RESULTS: We report the presence of YY2 protein in mouse-derived embryonic stem (ES) and TS cell lines. Following up on our previous report on ERV binding by YY2 in TS cells, we investigated the tissue-specificity of REX1 and YY2 binding and confirm binding to RE/ERV targets in both ES cells and TS cells. Because of the higher levels of expression, we chose TS cells to understand the role of Yy2 in gene and chromatin regulation. We used in vivo YY2 association as a measure to identify potential target genes. Sequencing of chromatin obtained in chromatin-immunoprecipitation (ChIP) assays carried out with αYY2 serum allowed us to identify a limited number of chromatin targets for YY2. Some putative binding sites were validated in regular ChIP assays and gene expression of genes nearby was altered in the absence of Yy2. CONCLUSIONS: YY2 binding to ERVs is not confined to TS cells. In vivo binding sites share the presence of a consensus binding motif. Selected sites were uniquely bound by YY2 as opposed to YY1, suggesting that YY2 exerts unique contributions to gene regulation. YY2 binding was not generally associated with gene promoters. However, several YY2 binding sites are linked to long noncoding RNA (lncRNA) genes and we show that the expression levels of a few of those are Yy2-dependent.

Regulation of Mouse Retroelement MuERV-L/MERVL Expression by REX1 and Epigenetic Control of Stem Cell Potency.

About half of the mammalian genome is occupied by DNA sequences that originate from transposable elements. Retrotransposons can modulate gene expression in different ways and, particularly retrotransposon-derived long terminal repeats, profoundly shape expression of both surrounding and distant genomic loci. This is especially important in pre-implantation development, during which extensive reprograming of the genome takes place and cells pass through totipotent and pluripotent states. At this stage, the main mechanism responsible for retrotransposon silencing, i.e., DNA methylation, is inoperative. A particular retrotransposon called muERV-L/MERVL is expressed during pre-implantation stages and contributes to the plasticity of mouse embryonic stem cells. This review will focus on the role of MERVL-derived sequences as controlling elements of gene expression specific for pre-implantation development, two-cell stage-specific gene expression, and stem cell pluripotency, the epigenetic mechanisms that control their expression, and the contributions of the pluripotency marker REX1 and the related Yin Yang 1 family of transcription factors to this regulation process.

Engineered drought-induced biosynthesis of α-tocopherol alleviates stress-induced leaf damage in tobacco.

Tocopherols are members of the vitamin E complex and essential antioxidant compounds synthesized in chloroplasts that protect photosynthetic membranes against oxidative damage triggered by most environmental stresses. Tocopherol deficiency has been shown to affect germination, retard growth and change responses to abiotic stress, suggesting that tocopherols may be involved in a number of diverse physiological processes in plants. Instead of seeking constitutive synthesis of tocopherols to improve stress tolerance, we followed an inducible approach of enhancing α-tocopherol accumulation under dehydration conditions in tobacco. Two uncharacterized stress inducible promoters isolated from Arabidopsis and the VTE2.1 gene from Solanum chilense were used in this work. VTE2.1 encodes the enzyme homogentisate phytyltransferase (HPT), which catalyzes the prenylation step in tocopherol biosynthesis. Transgenic tobacco plants expressing ScVTE2.1 under the control of stress-inducible promoters showed increased levels of α-tocopherol when exposed to drought conditions. The accumulation of α-tocopherol correlated with higher water content and increased photosynthetic performance and less oxidative stress damage as evidenced by reduced lipid peroxidation and delayed leaf senescence. Our results indicate that stress-induced expression of VTE2.1 can be used to increase the vitamin E content and to diminish detrimental effects of environmental stress in plants. The stress-inducible promoters introduced in this work may prove valuable to future biotechnological approaches in improving abiotic stress resistance in plants.

[Folic acid intake from diet and supplements in a population of pregnant women in Valencia, Spain]. / Ingesta dietética y de suplementos de ácido fólico en mujeres embarazadas de Valencia.

BACKGROUND AND OBJECTIVES: We examined the dietary intake and the use of supplements of folic acid (FA) in a cohort of pregnant women. We also explored the factors associated with non-compliance of both the recommended intake (RI) of 600 µg/day and the supplement use of 400 µg/day provided to prevent neural tube defects (NTD). PATIENTS AND METHODS: We studied 782 pregnant women from the INMA-Valencia cohort. The dietary intake was estimated using a food frequency questionnaire in two periods of pregnancy; from preconception to the second month and from the 3rd to the 7th month. Information on supplement use was also collected which allowed us to estimate the total FA intake (diet+supplements). We explored factors associated with non-compliance of the recommendations by logistic regression. RESULTS: The periconceptional mean daily FA intake was 304 µg/day. FA supplements were taken by 19.2, 30.2 and 66.2% of women in preconception, first and second month of pregnancy, respectively. Among women using supplements in periconception, 30% exceeded the tolerable upper intake level (UL) of 1.000 µg/day. Non-compliance with RI was more common among women of foreign origin, of low educational level, who smoked, with unplanned pregnancy, who did not visit a private gynaecologist, who had had children or without previous medical illness. CONCLUSIONS: Diet by itself is not sufficient to reach RI for FA during pregnancy and many women initiate supplement use after the recommended period and inadequately. The youngest women, with lowest educational attainment and unplanned pregnancies are more likely not to comply.

Ingesta dietética y de suplementos de ácido fólico en mujeres embarazadas de Valencia / Folic acid intake from diet and supplements in a population of pregnant women in Valencia, Spain

Fundamento y objetivos: Analizar la ingesta dietética y de suplementos de ácido fólico (AF) durante el embarazo y los factores asociados al incumplimiento de la ingesta recomendada (IR) de 600μg/d y al incumplimiento de 400μg/d de suplementos para prevenir los defectos del tubo neural. Pacientes y método: Se incluyeron a 782 embarazadas de la cohorte INMA-Valencia. La ingesta dietética se estimó mediante un cuestionario de frecuencia alimentaria en 2 períodos de embarazo, desde preconcepción al mes 2 y desde el mes 3–7. También se recogió información de la suplementación y se estimó la ingesta total de AF (dieta+suplementos). Usando regresión logística múltiple se exploraron los factores asociados al incumplimiento de las recomendaciones. Resultados: La ingesta dietética media periconcepcional de AF fue de 304μg/d. Un 19,2%, 30,2% y 66,2% de embarazadas tomaron suplementos de AF en preconcepción, primer y segundo mes, respectivamente. Por otra parte, alrededor del 30% de las mujeres que tomaban suplementos de AF en periconcepción superó el límite superior tolerable de 1.000μg/d. El ser no española, de bajo nivel de estudios, fumadora, no planificar el embarazo, no haber visitado a ginecólogo privado, haber tenido hijos y no haber tenido antecedentes médicos previos, se asoció al incumplimiento de la IR. Conclusiones: La dieta sola es insuficiente para alcanzar las IR de AF, puesto que la suplementación se hace tarde y mal. La situación se agrava en mujeres jóvenes, de menor nivel educativo y embarazo no planificado (AU)

Background and objectives: We examined the dietary intake and the use of supplements of folic acid (FA) in a cohort of pregnant women. We also explored the factors associated with non-compliance of both the recommended intake (RI) of 600μg/day and the supplement use of 400μg/day provided to prevent neural tube defects (NTD). Pacients and methods: We studied 782 pregnant women from the INMA-Valencia cohort. The dietary intake was estimated using a food frequency questionnaire in two periods of pregnancy; from preconception to the second month and from the 3rd to the 7th month. Information on supplement use was also collected which allowed us to estimate the total FA intake (diet+supplements). We explored factors associated with non-compliance of the recommendations by logistic regression. Results: The periconceptional mean daily FA intake was 304μg/day. FA supplements were taken by 19.2, 30.2 and 66.2% of women in preconception, first and second month of pregnancy, respectively. Among women using supplements in periconception, 30% exceeded the tolerable upper intake level (UL) of 1.000μg/day. Non-compliance with RI was more common among women of foreign origin, of low educational level, who smoked, with unplanned pregnancy, who did not visit a private gynaecologist, who had had children or without previous medical illness. Conclusions: Diet by itself is not sufficient to reach RI for FA during pregnanc and many women initiate supplement use after the recommended period and inadequately. The youngest women, with lowest educational attainment and unplanned pregnancies are more likely not to comply (AU)

Grave afectación laringotraqueal secundaria a rinoescleroma por Klebsiella pneumoniae ssp. ozaenae / No disponible

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