Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Medical Nanoimaging Pinpoints Cause of Cataracts

16.10.2007
At the Institut Curie, Simon Scheuring, beneficiary of the Inserm Avenir program and coordinator of the CNRS/Inserm “Atomic force microscopy (AFM) of proteins in native membranes” team(1), has for the first time observed a diseased tissue at very high resolution using atomic force microscopy (AFM).

By studying the membranes of cells in a patient’s eye cataract, Scheuring has discovered the molecular cause of this disease. This is the first time that high-resolution AFM imaging of a diseased tissue has yielded information on the single molecule level of the disease. AFM has emerged from the state-of-the-art laboratory to bring us medical nanoimaging. These results are now online in the Journal of Molecular Biology.

The eye’s lens focuses light and forms a sharp image on the retina thanks to the organization and specific properties of its constituent cells (see box overleaf). As in all tissues, cellular exchanges are essential for nutrition and removal of waste products, but in the eye they must nonetheless be adapted to the particular properties of the lens. The membranes of lens cells contain protein assemblies, the aquaporins and connexons (2): the former act as water channels and the latter as channels for metabolites and ions. Together these membrane proteins ensure cell adhesion.

Using atomic force microscopy (AFM), which images the surface of a sample at a precision of one nanometer (one billionth of a meter), Simon Scheuring’s team at the Institut Curie is studying how these protein assemblies function. An atomically sharp tip is scanned over the sample surface and its movements are tracked by a laser. The resulting data can be used to draw a topographical map of the sample. By comparing assemblies of aquaporins and connexons in membranes of healthy and diseased lens cells, Scheuring and colleagues have identified the biological changes that cause cataracts (see box overleaf).

In this senile cataract, lack of connexons prevents formation of the channels ensuring cell to cell communication. These molecular modifications explain the lack of adherence between cells, waste accumulation in cells, and the defective transport of water, ions, and metabolites in a lens with a cataract.

This is the first time that high-resolution AFM imaging of diseased tissue has shed light on the molecular cause of a disease at the single membrane protein level. A step towards medical nanoimaging has been taken with atomic force microscopy.

The lens
The specific properties of the eye’s lens cells enable the lens to function correctly. These cells have no nucleus or organelles, such as mitochondria, and are unable to perform certain biochemical functions essential for their nutrition, and therefore depend on transmembrane channels (3) for transport of water, ions, and metabolites, and for waste removal. These cells are full of so-called lens proteins (crystallins), which ensure lens transparency. To avoid any loss of light, the lens is avascular and its network of cells is extremely compact: the gap between neighboring cells must be less than the wavelength of visible light.
The cataract
The cataract results from opacification linked to the hardening of the lens. Age-related (senile) cataracts are by far the commonest, and affect more than one in five of the over-65s, over one in three of the over-75s, and two thirds of people over 85 years of age. Cataracts cause reduced image sharpness, blurred vision, and sensitivity to light and glare. The only effective treatment for cataracts at present is surgery, in which the opaque lens is removed and replaced by an artificial lens. Cataracts are the main cause of blindness in the third world and explain the sight loss of 40% of the world’s 37 million blind.
(1) “Atomic force microscopy of proteins in native membranes” team in the Curie Physical Chemistry research unit UMR 168 CNRS/Institut Curie directed by Jean-François Joanny.
(2) A connexon is an assembly of 6 connexin molecules and forms a gap junction between the cytoplasm of two adjacent cells.
(3) “The supramolecular architecture of junctional microdomains in native lens membranes”

N. Buzhynskyy, R. Hite, T. Walz, S Scheuring. EMBO R. January 2007, vol. 8, p. 51-55.

Catherine Goupillon | alfa
Further information:
http://www.sciencedirect.com/science/journal/00222836

Further reports about: AFM Cataracts Microscopy Scheuring cataract connexon diseased

More articles from Life Sciences:

nachricht Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery
20.01.2017 | GSI Helmholtzzentrum für Schwerionenforschung GmbH

nachricht Seeking structure with metagenome sequences
20.01.2017 | DOE/Joint Genome Institute

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>