Niveles de cortisol en saliva de cerdas reproductoras durante el destete, el estro y la inseminación y su relación con la fertilidad

Nuevos procedimientos de inseminación han sido incorporados en los programas de inseminación artificial en la especie porcina. Dichos procedimientos: inseminación intra-uterina (IIU), intra-uterina profunda (DUI) y por laparoscopia (LAP), facilitan la deposición de los espermatozoides más cerca del lugar de fecundación, no obstante implicanMuça, G. (2011). Niveles de cortisol en saliva de cerdas reproductoras durante el destete, el estro y la inseminación y su relación con la fertilidad. http://hdl.handle.net/10251/15894Archivo delegad

Uncoupling of EphA/ephrinA signaling and spontaneous activity in neural circuit wiring

Classic studies have proposed that genetically encoded programs and spontaneous activity play complementary but independent roles in the development of neural circuits. Recent evidence, however, suggests that these two mechanisms could interact extensively, with spontaneous activity affecting the expression and function of guidance molecules at early developmental stages. Here, using the developing chick spinal cord and the mouse visual system to ectopically express the inwardly rectifying potassium channel Kir2.1 in individual embryonic neurons, we demonstrate that cell-intrinsic blockade of spontaneous activity in vivo does not affect neuronal identity specification, axon pathfinding, or EphA/ephrinA signaling during the development of topographic maps. However, intrinsic spontaneous activity is critical for axon branching and pruning once axonal growth cones reach their correct topographic position in the target tissues. Our experiments argue for the dissociation of spontaneous activity from hard-wired developmental programs in early phases of neural circuit formation.This work was supported by grants from the Regional Government (Prometeo 2012-005) and the Spanish Government (BFU2010-16563) to E.H. (BFU2007-67834 and BFU2010-22220) to L.M., and from the European Research Council (ERC-2011-StG_20101109) to E.H. and (ERC-2009-StG_20081210) G.L.-B., I.B. and G.C. are Consolider-Ingenio fellows (CDS2007-023). A.K. is supported by the Canadian Institutes of Health Research (Operating Grant MOP-77556) and the Natural Sciences and Engineering Research Council of Canada. D.M. holds a Mexican Council for Science and Technology (Conacyt) graduate scholarship.Peer reviewe

The role of the transcription factor ZIC2 in neural crest development

Neural Crest cells (NCCs) are pluripotent cells that originate in the dorsal neuroephithelium of the dorsal neural tube and travel all over the embryo to contribute to the formation of many organs. The zinc finger transcription factor Zic2 (Zinc Finger of the Cerebellum protein 2) is known to participate in several steps of neural development including neurulation and neural crest formation. However, its precise role in these processes has not been yet clearly stated. Here, we show that Zic2 is expressed in premigratory but not in migrating NCCs. Then, functional experiments in vivo demonstrate that Zic2 expression is crucial for the formation of the NNCs but does not regulate cell death or cell fate. In an unbiased gene-wide screen performed in the chick neural tube, we identified the secreted protein Draxin/Neucrin as a possible Zic2 effector. We then confirm that spatiotemporal expression of Zic2 and Draxin in the dorsal tube are very similar and, functional experiments in chick demonstrate that Zic2 regulates Draxin/Neucrin expression during NCC formation. Finally, loss of function and gain of function studies confirm that Draxin/Neucrin partially recapitulates Zic2 functions during NCC migration. All these experiments together demonstrate that Zic2 plays a critical role during the progression of NCCs to get out of the neural tube and reveal that Zic2 induces Draxin/Neucrin expression during this process

Zic2 regulates Draxin to promote Neural Crest cells delamination

Resumen del póster presentado al 3rd AXON Meeting: “Circuits Development & Axon Regeneration”, celebrado en Alicante (España) del 11 al 13 de septiembre de 2019.También presentado al 5th Annual Retreat Developmental Neurobiology Unit, celebrado en el Instituto de Neurociencias de Alicante del 18 al 19 de febrero de 2019.The Neural Crest (NC) is a population of pluripotent cells that originate in the dorsal neuroephitelium of the neural tube and travel all over the embryo to contribute to the formation of many organs. The zinc finger transcription factor Zic2 participates in several steps of neural development including neural crest formation, being initially described as crucial for neural crest cells differentiation. However, Zic2 functional experiments in different species lead to disparate conclusions and today the precise role of this transcription factor in this process is still not well defined. Here, we first show that Zic2 is expressed in premigratory but not in migrating NC cells and demonstrate that, according to previous observations, downregulation of Zic2 in chick and mice produces a decreased number of migrating NC cells in the mesenchyme concomitant with an accumulation of NC cells at the dorsal tip of the neural tube. Conversely, Zic2 gain of function produces precocious exit of NC cells from the dorsal tube, indicating that Zic2 is necessary and sufficient to induce NC cells delamination. In addition, through an unbiased genome-wide screen we have identified the secreted molecule Draxin/Neucrin, an antagonist of the Wnt canonical signaling pathway, as a Zic2 target. Functional experiments in mouse and chick confirm that Zic2 regulates Draxin/Neucrin expression, which in turn contributes to regulate the onset of NC cells delamination. Together, these observations place Zic2 and its target Neucrin/Draxin as critical players on the delamination of NC cells.Peer reviewe

Molecular mechanisms underlying Zic2-associated holoprosencephaly

Trabajo presentado al 17th Meeting of the Spanish Society for Developmental Biology (SEBD), celebrado de forma virtual del 18 al 20 de noviembre de 2020.Mutations in the gene ZIC2 causes holoprosencephaly type 5 (HPE5) and other neurodevelopmental disorders. However, the molecular mechanisms by which the reduction of the transcription factor ZIC2 leads to these pathologies remain unclear. Here we demonstrate that Zic2 is transiently expressed in premigratory neural crest cells (NCCs) during neurulation. Transcriptomic analysis of Zic2 mutant embryos at this stage reveal that this TF regulates pathways involved in the epithelial-to-mesenchymal transition process (EMT) such as the Wnt or TGF-β pathways. Further functional experiments in mouse and chicken embryos demonstrate that Zic2 facilitates NCC delamination by blocking canonical Wnt signaling at the time that activates the TGF-β pathway. Gastrulation is also a process highly dependent on EMT and, during this early stage, Zic2 is transiently expressed in primitive streak cells and pluripotent cells of the three germ layers of the epiblast. Zic2 occupancy profile analysis in gastrula and neural crest cells point out a key role for Zic2 as a master regulator of important signaling cascades such as the Wnt and TGF-β pathways during gastrulation and neurulation. These results define the signaling cascades affected in Zic2-associated pathologies and may contribute to improving the diagnosis and genetic counseling of these conditions.Peer reviewe

Deregulation of the epithelial-to-mesenchymal transition process underlies Zic2-linked holoprosencephaly

Resumen del póster presentado al 19th Meeting Spanish Society of Neuroscience (SENC), celebrado en Lleida del 3 al 5 de noviembre de 2021.Holoprosencephaly (HPE) is a congenital brain malformation resulting from incomplete separation of the two hemispheres. Mutations in the Zic2 gene cause holoprosencephaly type 5, but the mechanisms that translate Zic2 mutations into this devastating pathology remain unclear. Here, we report that Zic2 is expressed in a few epiblast cells during gastrulation to become transiently upregulated in the primitive streak. Later, during neurulation, Zic2 is re-expressed in neural crest cells and downregulated as they delaminate from the neural tube. In combination with transcriptomic data from mutant embryos, chromatin occupancy profiles in gastrula and neural crest cells reveal that Zic2 regulates a large number of genes associated with the Wnt, cadherin and TGF-β pathways. In proliferating cells exposed to Wnt, Zic2 prevents the translocation of β- catenin to the nucleus, subsequently accumulating in the cytoplasm. This blocks activation of the canonical pathway inducing a non-canonical Wnt response necessary to initiate EMT. Our results elucidate the role of Zic2 in early development and provide an explanation for the wide variety of developmental alterations in HPE5 patients that, unlike other HPE patients, include many other mesoderm-derived defects. Altogether, these analyses identify cell types, signaling cascades, and genomic regions implicated in the etiology of Zic2-linked neurodevelopmental disorders.Peer reviewe

Deregulation of the WNT and TGF-β signaling pathways underlies Zic2-associated holoprosencephaly

Resumen del póster presentado al European Developmental Biology Congress (EDBC), celebrado en Alicante del 23 al 26 de octubre de 2019.The transcription factor Zic2 is one of the genes most commonly mutated in patients with holoprosencephaly (HPE), and in mice Zic2 mutations recapitulate the HPE phenotype. It has been shown that Zic2 transcripts are expressed during early stages of development including gastrulation and neurulation, two processes that imply an epithelial to mesenchymal transition (EMT) step and involve both the Wnt and BMP/TGFβ pathways. Despite intense research trying to unveil Zic2 functions during these early stages of development, little is still known about the precise function or the molecular program controlled by this transcription factor. Here, we describe for the first time the spatiotemporal expression of Zic2 during mouse gastrulation and neurulation. This detailed characterization of Zic2 expression in the early embryo reveals that it is not specific of a particular germ layer (ectoderm, mesoderm and endoderm) but it is transiently and dynamically detected in those layers undergoing EMT. Later, Zic2 is expressed in premigratory Neural Crest (NC) cells and it is then downregulated as soon as these cells leave the neural tube. Then, by performing Zic2 ChIP-seq and RNA-seq assays in E6.0-6.5 and E8.0-8.5 embryos we unveiled the Zic2-binding regions across the genome and define the set of genes regulated by Zic2 during these stages that include many genes related to the Wnt and the BMP/TGFβ pathways. Functional experiments in mouse and chicken then demonstrate that Zic2 inhibits the Wnt canonical signalling pathway in NC cells and induces delamination.Peer reviewe

Uncoupling of EphA/ephrinA Signaling and Spontaneous Activity in Neural Circuit Wiring

Classic studies have proposed that genetically encoded programs and spontaneous activity play complementary but independent roles in the development of neural circuits. Recent evidence, however, suggests that these two mechanisms could interact extensively, with spontaneous activity affecting the expression and function of guidance molecules at early developmental stages. Here, using the developing chick spinal cord and the mouse visual system to ectopically express the inwardly rectifying potassium channel Kir2.1 in individual embryonic neurons, we demonstrate that cell-intrinsic blockade of spontaneous activity in vivo does not affect neuronal identity specification, axon pathfinding, or EphA/ephrinA signaling during the development of topographic maps. However, intrinsic spontaneous activity is critical for axon branching and pruning once axonal growth cones reach their correct topographic position in the target tissues. Our experiments argue for the dissociation of spontaneous activity from hard-wired developmental programs in early phases of neural circuit formation

Goji Berry in the Diet of the Rabbit Buck: Effects on Semen Quality, Oxidative Status and Histological Features of the Reproductive Tract

Goji berry (GB) shows beneficial effects on human health, although its effects on the male rabbit have been little investigated. This study examines the impact of GB dietary supplementation on the semen traits, antioxidant capacity of seminal plasma, and histological features of the reproductive tract of rabbit buck. Eighteen rabbits were distributed into two dietary groups: one receiving a commercial feed (Control), and the other a feed supplemented with 1% of GB (Goji). After a nutritional adaptation period of 60 days, the animals were subjected to semen collection every 15 days. The semen traits, libido, antioxidant, and inflammatory parameters were collected and analyzed. The rabbits were sacrificed after 60 days, and tissues of the genital tract were analyzed. Compared to the Control group, the Goji group showed higher spermatozoa concentration, motility, and vitality (p p p < 0.05). Conversely, antioxidant and anti-inflammatory parameters were unaffected by the diet. These findings suggest that GB acts on the tissues of the reproductive tract positively influencing semen quality, although further studies are needed to understand the effect on oxidative stress