Ectopic release of nitric oxide modulates the onset of cardiac development in avian model.

Heart development is one of the earliest developmental events, and its pumping action is directly linked to the intensity of development of other organs. Heart contractions mediate the circulation of the nutrients and signalling molecules to the focal points of developing embryos. In the present study, we used in vivo, ex vivo, in vitro, and in silico methods for chick embryo model to characterize and identify molecular targets under the influence of ectopic nitric oxide in reference to cardiogenesis. Spermine NONOate (SpNO) treatment of 10 µM increased the percentage of chick embryos having beating heart at 40th h of incubation by 2.2-fold (p < 0.001). In an ex vivo chick embryo culture, SpNO increased the percentage of embryos having beats by 1.56-fold (p < 0.05) compared with control after 2 h of treatment. Total body weight of SpNO-treated chick embryos at the Hamburger and Hamilton (HH) stage 29 was increased by 1.22-fold (p < 0.005). Cardiac field potential (FP) recordings of chick embryo at HH29 showed 2.5-fold (p < 0.001) increased in the amplitude, 3.2-fold (p < 0.001) increased in frequency of SpNO-treated embryos over that of the control group, whereas FP duration was unaffected. In cultured cardiac progenitors cells (CPCs), SpNO treatment decreased apoptosis and cell death by twofold (p < 0.001) and 1.7-fold (p < 0.001), respectively. Transcriptome analysis of chick embryonic heart isolated from HH15 stage pre-treated with SpNO at HH8 stage showed upregulation of genes involved in heart morphogenesis, heart contraction, cardiac cell development, calcium signalling, structure, and development whereas downregulated genes were enriched under the terms extracellular matrix, wnt pathway, and BMP pathway. The key upstream molecules predicted to be activated were p38 MAPK, MEF2C, TBX5, and GATA4 while KDM5α, DNMT3A, and HNF1α were predicted to be inhibited. This study suggests that the ectopic nitric oxide modulates the onset of cardiac development.

Thalidomide remodels developing heart in chick embryo: discovery of a thalidomide mediated hematoma in heart muscle.

Despite of medical disaster caused by thalidomide in 1960s, the drug came to clinical use again for the treatment of erythema nodosum leprosum (ENL) and multiple myeloma. Recently, a new generation of children affected by thalidomide intake by their mothers during pregnancy has been identified in Brazil. In the past few years, there is the great enhancement in our understanding of the molecular mechanisms and targets of thalidomide with the help of modern OMICS technologies. However, understanding of cardiac-specific anomalies in fetus due to thalidomide intake by the respective mother has not been explored fully. At organ level, thalidomide causes congenital heart diseases, limb deformities in addition to ocular, and neural and ear abnormalities. The period of morning sickness and cardiogenesis is synchronized in pregnant women. Therefore, thalidomide intake during the first trimester could affect cardiogenesis severely. Thalidomide intake in pregnant women either causes miscarriage or heart abnormalities such as patent ductus arteriosus, ventricular septal defect (VSD), atrial septal defect (ASD), and pulmonary stenosis in survivors. In the present study, we identified a novel morphological defect (lump) in the heart of thalidomide-treated chick embryos. We characterized the lump at morphological, histo-pathological, oxidative stress, electro-physiological, and gene expression level. To our knowledge, here, we report the very first electrophysiological characterization of embryonic heart affected by thalidomide treatment.

Harvesting clues from genome wide transcriptome analysis for exploring thalidomide mediated anomalies in eye development of chick embryo: Nitric oxide rectifies the thalidomide mediated anomalies by swinging back the system to normal transcriptome pattern.

Thalidomide, the notorious teratogen is known to cause various developmental abnormalities, among which a range of eye deformations are very common. From the clinical point of view, it is necessary to pinpoint the mechanisms of teratogens that tune the gene expression. However, to our knowledge, the molecular basis of eye deformities under thalidomide treatmenthas not been reported so far. Present study focuses on the possible mechanism by which thalidomide affects eye development and the role of Nitric Oxide in recovering thalidomide-mediated anomalies of eye development using chick embryo and zebrafish models with transcriptome analysis. Transcriptome analysis showed that 403 genes were up-regulated and 223 genes were down-regulated significantly in thalidomide pre-treated embryos. 8% of the significantly modulated genes have been implicated in eye development including Pax6, OTX2, Dkk1 and Shh. A wide range of biological process and molecular function was affected by thalidomide exposure. Biological Processes including structural constituent of eye lens and Molecular functions such as visual perception and retinal metabolic process formed strong annotation clustersindicating the adverse effects of thalidomide on eye development and function. Here, we have discussed the whole embryo transcriptome with the expression of PAX6, SOX2, and CRYAAgenes from developing eyes. Our experimental data showing structural and functional aspects includingeye size, lens transparency and optic nerve activity and bioinformatics analyses of transcriptome suggest that NO could partially protect thalidomide treated embryos from its devastating effects on eye development and function.