Asymmetry is crucial for the heart proper functioning, and now, scientists from the Institute Gulbenkian of Science in Portugal and Harvard University, have discovered that a family of genes, called Nodal, is crucial determining this asymmetry by controlling the speed and direction of the heart muscle cells during embryonic development. The finding, by helping to understand how the heart develops, is a step closer to intervene and is of particular importance if we consider that problems in heart asymmetry are the main cause of heart congenital diseases that can affect as much as 8 out of 1000 newborns. The research will appear in a special December issue of the journal Development Dynamics 1 dedicated to left-right asymmetry development.
At first glance, the left and right sides of our bodies are identical to one-another. Inside, however, it is quite a different story and organ asymmetry is believed to improve not only the packaging of the organs, but also their proper functioning. The normal disposition of internal organs and structures, which is conserved within vertebrates, is called situs solitus. Alterations of this state include full mirror-reversal organ disposition- a pathology made famous by news of people stabbed in the heart just to discover that their heart was in fact on the opposite side of the body - or cases where individuals have two right or two left sides. But, despite the fact that most alterations in the normal positioning of human organs originate severe medical conditions, very little is actually known about the events behind this type of development. As such, to understand them is not only a fundamental question of Developmental Biology but also highly relevant for human health. This is of particular importance with the heart, which is incredible susceptible to any changes in its normal asymmetry, as the high mortality and disease rates in patients with congenital heart defects so clearly demonstrate.
With this in mind Maria Ines Medeiros de Campos-Baptista and Alexander F. Schier from the Institute Gulbenkian of Science (Lisbon, Portugal) and the Harvard University (Cambridge, USA) and colleagues decided to analyse the expression of the Nodal gene family – which has been linked to left-right axis determination in vertebrates - during the development of zebrafish heart.
Genes linked to asymmetric development are active in the embryo very early during development and only on one side and in fact, the researchers found that some Nodal were expressed at the onset of asymmetry, on left side of the embryo and even co-localizing with heart markers supporting the idea that this family was in fact involved in the asymmetric development of the heart.
To investigate this further Campos-Baptista, Schier and colleagues used a powerful 4D microscope technique that allows to follow individual cells, to film, in real time, the heart development of zebrafish embryos that have been modified to express green fluorescent protein (GFP) in their heart muscle cells (or cardiomyocytes). The idea was that with this marker - together with the fact that zebrafish embryos are transparent - it was possible to track of individual cardiomyocytes as the heart developed to determine the importance of Nodal genes in this development. By comparing animals with or without functional Nodal, the researchers found that these genes regulated the speed and direction of cardiomyocytes, and, when lacking, led to slower and randomly moving cardiomyocytes that losing their asymmetric behaviour, go and form a symmetrically positioned heart (so localised on the body midline).
Nevertheless, although problems in the Nodal genes do affect heart positioning, the fact that this organ is still formed and the organism is viable – although probably not too healthy - reveals that other independent mechanisms, regulated by other genes, affect the same development.
In conclusion, Campos-Baptista, Schier and colleagues’ results show that the movement of individual cardiomyocytes is the determining force behind heart morphogenesis, and that the Nodal genes, by controlling the speed and direction of individual heart muscle cells, are in fact responsible for the asymmetric formation of the heart
“The next step - according to Ines Campos-Baptista, a Portuguese researcher and the first author of the article - will be to identify other genes this time behind the particular movements of the cardiac cells, such as those linked to the cell skeleton, etc. Identifying these will be crucial to fully understand heart asymmetric formation and - since Nodal also plays a role in this developmental of other organs - it will also shed light on the development of many other internal organs such as the pancreas, gut, lungs, etc.”
Campos-Baptista, Schier and colleagues’ findings are important for a better understanding of the mechanism behind embryonic development., specifically of the heart, and, as such, can take us a little closer to one day to be able, not only of preventing heart congenital anomalies, but also of being able to grow our own heart tissues. Although that time is still a long, long way away.
Piece by Catarina Amorim (catarina.amorim at linacre.ox.ac.uk)
Catarina Amorim | alfa
A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
On the way to developing a new active ingredient against chronic infections
21.08.2017 | Deutsches Zentrum für Infektionsforschung
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
21.08.2017 | Medical Engineering
21.08.2017 | Materials Sciences
21.08.2017 | Life Sciences