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 Researchers uncover protein-based “cancer signature”
05.12.2016 | Universität Basel

nachricht The Nagoya Protocol Creates Disadvantages for Many Countries when Applied to Microorganisms
05.12.2016 | Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

IHP presents the fastest silicon-based transistor in the world

05.12.2016 | Power and Electrical Engineering

InLight study: insights into chemical processes using light

05.12.2016 | Materials Sciences

High-precision magnetic field sensing

05.12.2016 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>