Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mice with glowing hearts shed light on living cells

09.03.2006


There is the heart of gold, and then there is the heart that glows. Literally.


Provided by Kotlikoff et al.
This series reveals increases in cell calcium from a mouse embryo’s upper heart through the lower heart on day 10 of development. Cell calcium rises when muscles contract. The bottom row shows a dramatic slowing of the conducted calcium wave between the upper and lower heart chambers.



Cornell researchers have genetically engineered mice whose hearts glow with a green light every time they beat. The development gives researchers insights into how hearts develop in living mouse embryos and could improve our understanding of irregular heartbeats, known as arrhythmias, as well as open doors to observing cellular processes to better understand basic physiology and disease.

The technique for making living, functional cells fluoresce, or glow, when the concentration of calcium ions rise within cells, is described online at http://www.pnas.org/papbyrecent.shtml and is to be published in a future issue of Proceedings of the National Academy of Sciences.


"The proteins act as molecular spies that tell us what is happening within cells in the living mouse," said Michael Kotlikoff, professor and chair of the Department of Biomedical Sciences at Cornell’s College of Veterinary Medicine.

Cornell researchers are breeding new lines of mice with similar proteins that target neurons in the brain, in parasympathetic nerves, in blood vessels or in Purkinje fibers, which prompt the heart’s ventricles to pump. The researchers have also transplanted cells from the mice with glowing hearts into normal mice to see whether the transplanted cells function normally within the host heart, which could offer insights for heart repair.

In the study, the mouse was engineered to express a specially designed molecule that fluoresces when calcium, which increases dramatically with each muscle contraction, is released in heart cells. Co-author Junichi Nakai of the RIKEN Brain Science Institute in Wako-shi, Japan, developed the fluorescent molecule by modifying a green fluorescent protein (derived from bioluminescent jellyfish) and making it glow brightly enough to be observed in the working heart.

Calcium turns the sensor molecule off and on like a molecular switch. Greater fluorescence indicates higher calcium levels, and the sensor shows the patterns, rate and force of heart contractions.

Since the mouse heart beats approximately 6 to 10 times per second, imaging requires a special high-speed camera that is cooled to minus 90 degrees Celsius (minus 128 Fahrenheit), reducing "noise" for a sharper image. Co-author Guy Salama of the University of Pittsburgh contributed the optical imaging work.

Using this technique, the researchers were able to track the embryo’s developing heart to glean insights into how the heart forms. In mammals, the heart is the first organ to function and starts beating prior to its full development.

"We knew that the heart starts to pump at around 9.5 days," said Kotlikoff. By day 10.5, there are only two chambers (rather than four chambers in an adult mammal): an atrium on top and a ventricle on the bottom. A delay in beats between the two gives the atrium time to contract and push blood through the heart, but the mechanism that controls that signal, the atrio-ventricular node (AV node), doesn’t develop until day 13. Nobody knew how the heart coordinated the pumping without this key component.

"We knew there had to be a delay in this, but we had no idea how it occurred," said Kotlikoff.

Using the new technique, which tracks the rise of calcium as the heart muscle contracts, the researchers discovered a layer of specialized cells on the surface of the developing heart that delays the beating between the upper to lower parts of the heart. After 13.5 days of development, the two portions of the heart separate into four, and there is a functional AV node. By that time, the technique revealed, the specialized cells have died so that functions are not duplicated.

"These cells have to die, because if they didn’t the heart would not function properly," said Kotlikoff.

The study was funded by the National Institutes of Health and Japan’s Ministry of Education, Culture, Sports Science and Technology.

Blaine Friedlander | EurekAlert!
Further information:
http://www.cornell.edu

More articles from Life Sciences:

nachricht Decoding the genome's cryptic language
27.02.2017 | University of California - San Diego

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Safe glide at total engine failure with ELA-inside

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

New pop-up strategy inspired by cuts, not folds

27.02.2017 | Materials Sciences

Sandia uses confined nanoparticles to improve hydrogen storage materials performance

27.02.2017 | Interdisciplinary Research

Decoding the genome's cryptic language

27.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>