RESUMEN
Boron is an essential trace element in cellular metabolism; however, the molecular mechanism of boron in the heart is unclear. In this study, we examined the effect of sodium tetraborate (as boron source) as a possible protective agent or competitive inhibitor of cardiac hypertrophy in an in vitro murine model. We evaluated different previously reported sodium tetraborate concentrations and it was found that 13⯵M improves viability without affecting the cellular structure. We demonstrated that cardiomyocytes pretreated with sodium tetraborate prevents cellular damage induced by isoproterenol (cardioprotective effect) by increasing proliferation rate and inhibiting apoptosis. In addition, the reduction of the expression of the α1AR and ß1AR adrenergic receptors as well as Erk1/2 was notable. Consequently, the expression of the early response genes c-myc, c-fos and c-jun was delayed. Also, the expression of GATA-4, NFAT, NKx2.5 and myogenin transcription factors involved in sarcomere synthesis declined. In contrast, cardiomyocytes, when treated simultaneously with sodium tetraborate and isoproterenol, did not increase their size (cytoplasmic gain), but an increase in apoptosis levels was observed; therefore, the proliferation rate was reduced. Although the mRNA levels of α1AR and ß1AR as well as Erk1/2 and Akt1 were low at 24â¯h, their expression increased to 48â¯h. Notably, the mRNA of expression levels of c-myc, c-fos and c-jun were lower than those determined in the control, while the transcription factors GATA-4, MEF2c, Nkx2.5, NFAT and CDk9 were determined in most cells. These results suggest that pretreatment with sodium tetraborate in cardiomyocytes inhibits the hypertrophic effect. However, sodium tetraborate attenuates isoproterenol induced hypertrophy damage in cardiomyocytes when these two compounds are added simultaneously.
Asunto(s)
Boratos/farmacología , Cardiomegalia/inducido químicamente , Cardiomegalia/metabolismo , Cardiotónicos/farmacología , Miocitos Cardíacos/efectos de los fármacos , Animales , Apoptosis/efectos de los fármacos , Boratos/administración & dosificación , Boratos/efectos adversos , Cardiotónicos/efectos adversos , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Regulación de la Expresión Génica/efectos de los fármacos , Isoproterenol/administración & dosificación , Isoproterenol/efectos adversos , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Ratones Endogámicos BALB C , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Receptores Adrenérgicos alfa 1/genética , Receptores Adrenérgicos beta 2/genética , Transducción de Señal/efectos de los fármacos , Factores de Transcripción/metabolismoRESUMEN
Complex congenital heart disease (CHD) affects cardiac blood flow, generating a pressure overload in the compromised ventricles and provoking hypertrophy that over time will induce myocardial dysfunction and cause a potential risk of imminent death. Therefore, the early diagnosis of complex CHD is paramount during the first year of life, with surgical treatment of patients favoring survival. In the present study, we analyzed cardiac tissue and plasma of children with cardiac hypertrophy (CH) secondary to CHD for the expression of 11 miRNAs specific to CH in adults. The results were compared with the miRNA expression patterns in tissue and blood of healthy children. In this way, we determined that miRNAs 1, 18b, 21, 23b, 133a, 195, and 208b constitute the expression profile of the cardiac tissue of children with CHD. Meanwhile, miRNAs 21, 23a, 23b, and 24 can be considered specific biomarkers for the diagnosis of CH in infants with CHD. These results suggest that CH secondary to CHD in children differs in its mechanism from that described for adult hypertrophy, offering a new perspective to study the development of this pathology and to determine the potential of hypertrophic miRNAs to be biomarkers for early CH.
Asunto(s)
Cardiomegalia/genética , Cardiopatías Congénitas/genética , MicroARNs/genética , Biomarcadores/análisis , Biopsia , Niño , Preescolar , Femenino , Cardiopatías Congénitas/complicaciones , Ventrículos Cardíacos/patología , Humanos , Lactante , Recién Nacido , Masculino , MicroARNs/análisis , TranscriptomaRESUMEN
The apoptosis of ß cells induced by hyperglycemia has been associated with p53 mobilization to mitochondria and p53 phosphorylation. Murine double minute 2 (Mdm2) induces the degradation of p53 and thereby protects cells from apoptosis. We studied the effect of glucose at high concentration on the ability of Mdm2 to ubiquitinate p53 and promote its degradation. RINm5F cells were grown in RPMI-1640 medium with 5 or 30 mM glucose for varying periods of time. After this treatment, the expression of Mdm2 was measured using real-time PCR. The phosphorylation of Mdm2 at Ser166, p53 at Ser15, and the kinases Akt and ATM were measured by Western blotting. The formation of the p53-Mdm2 complex and p53 ubiquitination was assessed by p53 immunoprecipitation and immunofluorescence. Our results showed that high glucose reduced Mdm2 mRNA expression and protein concentration and increased Mdm2 and Akt phosphorylation, albeit with slower kinetics for Akt. It also promoted p53-Mdm2 complex formation, whereas p53 ubiquitination was suppressed. Furthermore, phosphorylation of both p53 Ser15 and ATM was increased in the presence of 30 mM glucose. These data indicate that high concentration glucose decrease the mRNA expression and cytosolic concentration of Mdm2. However, although the increase in glucose promoted the phosphorylation of Mdm2, it also decreased p53 ubiquitination, thus avoiding p53 degradation. In hyperglycemic conditions, such as diabetes mellitus, the reduction of pancreatic ß cells mass is favored by stabilization of p53 in association with low p53 ubiquitination and reduced expression of Mdm2.
Asunto(s)
Glucosa/metabolismo , Hiperglucemia/metabolismo , Proteínas Proto-Oncogénicas c-mdm2/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Ubiquitinación/fisiología , Animales , Apoptosis/fisiología , Línea Celular Tumoral , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/fisiología , Mitocondrias/metabolismo , Mitocondrias/fisiología , Fosforilación/fisiología , Proteínas Proto-Oncogénicas c-akt/metabolismo , ARN Mensajero/genética , RatasRESUMEN
The main objective of this study was to create a postnatal model for cardiac hypertrophy (CH), in order to explain the mechanisms that are present in childhood cardiac hypertrophy. Five days after implantation, intraperitoneal (IP) isoproterenol (ISO) was injected for 7 days to pregnant female mice. The fetuses were obtained at 15, 17 and 19 dpc from both groups, also newborns (NB), neonates (7-15 days) and young adults (6 weeks of age). Histopathological exams were done on the hearts. Immunohistochemistry and western blot demonstrated GATA4 and PCNA protein expression, qPCR real time the mRNA of adrenergic receptors (α-AR and ß-AR), alpha and beta myosins (α-MHC, ß-MHC) and GATA4. After the administration of ISO, there was no change in the number of offsprings. We observed significant structural changes in the size of the offspring hearts. Morphometric analysis revealed an increase in the size of the left ventricular wall and interventricular septum (IVS). Histopathological analysis demonstrated loss of cellular compaction and presence of left ventricular small fibrous foci after birth. Adrenergic receptors might be responsible for changing a physiological into a pathological hypertrophy. However GATA4 seemed to be the determining factor in the pathology. A new animal model was established for the study of pathologic CH in early postnatal stages.
RESUMEN
In a first paper, we concluded that the muscular region of the interventricular septum is developed by the trabecular branches and showed evidence that the developing interventricular septum elongates in a direction opposite to that of atria. Nevertheless, to date the literature is lacking precise information on the importance of myocardial proliferation not only in this process but also in the morphogenesis of the ventricular cavities. The aim of this study was to determine the spatial and temporal distribution of high-intensity foci of cycling myocytes in the ventricular region of the heart of chicken embryos during cardiac septation. Histological studies, detection of the proliferating cell nuclear antigen by light and confocal microscopy and flow cytometric analysis were carried out. The results corroborate that the developing interventricular septum grows in a direction opposite to that of atria. A remoulding mechanism that results in fenestrated trabecular sheets and trabecular branching is discussed. Our findings allowed us to summarize the normal morphogenesis of the muscular region of the interventricular septum in a way that is different from that suggested by other researchers.
Asunto(s)
Embrión de Pollo/anatomía & histología , Tabiques Cardíacos/embriología , Ventrículos Cardíacos/embriología , Corazón/embriología , Miocitos Cardíacos/metabolismo , Animales , Tabiques Cardíacos/citología , Ventrículos Cardíacos/citología , Morfogénesis , Miocardio/metabolismoRESUMEN
We report the analysis by ELISA of class and subclass antibody response against a total soluble extract from T. spiralis adult stage (TSE-A) during a year after the infection in 17 symptomatic trichinellosis patients (SI) and five asymptomatic individual (AI) involved in an outbreak of trichinellosis occurred in the State of Mexico. Serum samples from 20 healthy individuals (HI) and 24 patients with other parasitosis were included as control. All SI showed a polyisotypic antibody response against the TSE-A, during the infection. Higher response of IgA, IgE, IgM were detected in SI during the acute phase of the infection, but only IgE remained at high levels all along the infection. None or a lower reactivity against TSE-A was observed in sera from AI and from HI. Some patients with trichuriosis and ascariosis showed a higher cross-reactivity, against TSE-A when IgG and their subclasses were analyzed.