Alba Betancourt - Academia.edu (original) (raw)
Uploads
Papers by Alba Betancourt
General and Comparative Endocrinology, 2015
Growth hormone (GH) is expressed in several extra-pituitary tissues, including the primary and se... more Growth hormone (GH) is expressed in several extra-pituitary tissues, including the primary and secondary lymphoid organs of the immune system. In birds, GH mRNA and protein expression show a specific developmental distribution pattern in the bursa of Fabricius (BF), particularly in epithelial and B cells. Changes in the bursal concentration and distribution of locally produced GH during ontogeny suggest it is involved in B cell differentiation and maturation, as well as in a functional survival role in this organ, which may be mediated by paracrine/autocrine mechanisms. Here, we analyzed the anti-apoptotic effect of GH in BF and the intracellular signaling pathways involved in this activity. Also, we studied if this effect was exerted directly by GH or mediated indirectly by IGF-I. Bursal cell cultures showed an important loss of their viability after 4h of incubation and a significant increase in apoptosis. However, treatment with 10nM GH or 40nM IGF-I significantly increased B cell viability (16.7±0.67% and 13.4±1.12%, respectively) when compared with the untreated controls. In addition, the presence of apoptotic bodies (TUNEL) dramatically decreased (5.5-fold) after GH and IGF-I treatments, whereas co-incubation with anti-GH or anti-IGF-I, respectively, blocked their anti-apoptotic effect. Likewise, both GH and IGF-I significantly inhibited caspase-3 activity (by 40±2.0%) in these cultures. However, the use of anti-IGF-I could not reverse the GH anti-apoptotic effects, thus indicating that these were exerted directly. The addition of 100nM wortmannin (a PI3K/Akt inhibitor) blocked the GH protective effects. Also, GH stimulated (3-fold) the phosphorylation of Akt in bursal cells, and adding wortmannin or an anti-GH antibody inhibited this effect. Furthermore, GH was capable to stimulate (7-fold) the expression of Bcl-2. Taken together, these results indicate that the direct anti-apoptotic activity of GH observed in the chicken bursal B cell cultures might be mediated through the PI3K/Akt pathway.
General and Comparative Endocrinology, 2014
General and Comparative Endocrinology, 2011
Although growth hormone (GH) is mainly synthesized and secreted by pituitary somatotrophs, it is ... more Although growth hormone (GH) is mainly synthesized and secreted by pituitary somatotrophs, it is now well established that the GH gene can be expressed in many extrapituitary tissues, including the central nervous system (CNS). Here we studied the expression of GH in the chicken cerebellum. Cerebellar GH expression was analyzed by in situ hybridization and cDNA sequencing, as well as by immunohistochemistry and confocal microscopy. GH heterogeneity was studied by Western blotting. We demonstrated that the GH gene was expressed in the chicken cerebellum and that its nucleotide sequence is closely homologous to pituitary GH cDNA. Within the cerebellum, GH mRNA is mainly expressed in Purkinje cells and in cells of the granular layer. GH-immunoreactivity (IR) is also widespread in the cerebellum and is similarly most abundant in the Purkinje and granular cells as identified by specific neuronal markers and histochemical techniques. The GH concentration in the cerebellum is age-related and higher in adult birds than in embryos and juveniles. Cerebellar GH-IR, as determined by Western blot under reducing conditions, is associated with several size variants (of 15, 23, 26, 29, 35, 45, 50, 55, 80 kDa), of which the 15 kDa isoform predominates (>30% among all developmental stages). GH receptor (GHR) mRNA and protein are also present in the cerebellum and are similarly mainly present in Purkinje and granular cells. Together, these data suggest that GH and GHR are locally expressed within the cerebellum and that this hormone may act as a local autocrine/paracrine factor during development of this neural tissue.
La arteroesclerosis es un proceso inflamatorio cronico en la cual las arterias son afectadas y da... more La arteroesclerosis es un proceso inflamatorio cronico en la cual las arterias son afectadas y da lugar a las enfermedades cardiovasculares, las cuales son la primera causa de muerte en nuestro pais. Se han determinado factores de riesgo independientes entre los cuales se encuentran niveles sericos elevados de colesterol total, colesterol LDL, trigliceridos y lipoproteinas. El fibrinogeno es una glicoproteina cuya principal funcion en el proceso de coagulacion es transformarse por accion de la trombina en fibrina insoluble. Diversos estudios han sugerido una posible relacion entre los niveles de fibrinogeno y enfermedad cardiovascular. En este trabajo se realizo un estudio transversal en 100 pacientes masculinos ambulatorios en la clinica Hospital ISSSTE Guanajuato a quienes se les midieron perfil de lipidos y fibrinogeno. Los pacientes que presentaron valores normales de fibrinogeno mostraron una correlacion negativa con los valores de HDL; con respecto a los valores aumentados de ...
General and Comparative Endocrinology, 2015
Growth hormone (GH) is expressed in several extra-pituitary tissues, including the primary and se... more Growth hormone (GH) is expressed in several extra-pituitary tissues, including the primary and secondary lymphoid organs of the immune system. In birds, GH mRNA and protein expression show a specific developmental distribution pattern in the bursa of Fabricius (BF), particularly in epithelial and B cells. Changes in the bursal concentration and distribution of locally produced GH during ontogeny suggest it is involved in B cell differentiation and maturation, as well as in a functional survival role in this organ, which may be mediated by paracrine/autocrine mechanisms. Here, we analyzed the anti-apoptotic effect of GH in BF and the intracellular signaling pathways involved in this activity. Also, we studied if this effect was exerted directly by GH or mediated indirectly by IGF-I. Bursal cell cultures showed an important loss of their viability after 4h of incubation and a significant increase in apoptosis. However, treatment with 10nM GH or 40nM IGF-I significantly increased B cell viability (16.7±0.67% and 13.4±1.12%, respectively) when compared with the untreated controls. In addition, the presence of apoptotic bodies (TUNEL) dramatically decreased (5.5-fold) after GH and IGF-I treatments, whereas co-incubation with anti-GH or anti-IGF-I, respectively, blocked their anti-apoptotic effect. Likewise, both GH and IGF-I significantly inhibited caspase-3 activity (by 40±2.0%) in these cultures. However, the use of anti-IGF-I could not reverse the GH anti-apoptotic effects, thus indicating that these were exerted directly. The addition of 100nM wortmannin (a PI3K/Akt inhibitor) blocked the GH protective effects. Also, GH stimulated (3-fold) the phosphorylation of Akt in bursal cells, and adding wortmannin or an anti-GH antibody inhibited this effect. Furthermore, GH was capable to stimulate (7-fold) the expression of Bcl-2. Taken together, these results indicate that the direct anti-apoptotic activity of GH observed in the chicken bursal B cell cultures might be mediated through the PI3K/Akt pathway.
General and Comparative Endocrinology, 2014
General and Comparative Endocrinology, 2011
Although growth hormone (GH) is mainly synthesized and secreted by pituitary somatotrophs, it is ... more Although growth hormone (GH) is mainly synthesized and secreted by pituitary somatotrophs, it is now well established that the GH gene can be expressed in many extrapituitary tissues, including the central nervous system (CNS). Here we studied the expression of GH in the chicken cerebellum. Cerebellar GH expression was analyzed by in situ hybridization and cDNA sequencing, as well as by immunohistochemistry and confocal microscopy. GH heterogeneity was studied by Western blotting. We demonstrated that the GH gene was expressed in the chicken cerebellum and that its nucleotide sequence is closely homologous to pituitary GH cDNA. Within the cerebellum, GH mRNA is mainly expressed in Purkinje cells and in cells of the granular layer. GH-immunoreactivity (IR) is also widespread in the cerebellum and is similarly most abundant in the Purkinje and granular cells as identified by specific neuronal markers and histochemical techniques. The GH concentration in the cerebellum is age-related and higher in adult birds than in embryos and juveniles. Cerebellar GH-IR, as determined by Western blot under reducing conditions, is associated with several size variants (of 15, 23, 26, 29, 35, 45, 50, 55, 80 kDa), of which the 15 kDa isoform predominates (>30% among all developmental stages). GH receptor (GHR) mRNA and protein are also present in the cerebellum and are similarly mainly present in Purkinje and granular cells. Together, these data suggest that GH and GHR are locally expressed within the cerebellum and that this hormone may act as a local autocrine/paracrine factor during development of this neural tissue.
La arteroesclerosis es un proceso inflamatorio cronico en la cual las arterias son afectadas y da... more La arteroesclerosis es un proceso inflamatorio cronico en la cual las arterias son afectadas y da lugar a las enfermedades cardiovasculares, las cuales son la primera causa de muerte en nuestro pais. Se han determinado factores de riesgo independientes entre los cuales se encuentran niveles sericos elevados de colesterol total, colesterol LDL, trigliceridos y lipoproteinas. El fibrinogeno es una glicoproteina cuya principal funcion en el proceso de coagulacion es transformarse por accion de la trombina en fibrina insoluble. Diversos estudios han sugerido una posible relacion entre los niveles de fibrinogeno y enfermedad cardiovascular. En este trabajo se realizo un estudio transversal en 100 pacientes masculinos ambulatorios en la clinica Hospital ISSSTE Guanajuato a quienes se les midieron perfil de lipidos y fibrinogeno. Los pacientes que presentaron valores normales de fibrinogeno mostraron una correlacion negativa con los valores de HDL; con respecto a los valores aumentados de ...