Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Big eyes! – MDC Researchers Identify Cause of Inherited Form of Extreme Nearsightedness

02.10.2015

“Why, Grandma, what big eyes you have!” Though similar in appearance, the hidden cause of those big eyes Little Red Riding Hood notices in Grimms’ fairy tale has nothing to do with the hidden cause of enlarged eyeballs in buphthalmia, a genetic mechanism causing this devastating eye disease which has now been uncovered by Dr. Annabel Christ and Prof. Thomas Willnow from the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC). Patients afflicted are severely myopic, or nearsighted (Developmental Cell, http://dx.doi.org/10.1016/j.devcel.2015.09.001)⃰⃰⃰⃰⃰⃰.

Babies’ eyes are almost as large as those of an adult because human eyes grow very little after birth. Things are different with reptiles and fish. Their eyes grow constantly, although they have the same structure as mammalian eyes, i.e. those of humans.

What inhibits the growth of mammalian eyes had not been previously understood. It was known, though, that excessive growth of human eyes leads to myopia or nearsightedness, since the eyeball becomes too long and the light falling on the eye cannot be focused on the retina.

Dr. Christ, who works as an independent Helmholtz Fellow at the MDC, and Prof. Willnow have now established the mechanism that restricts growth of the human eye and how it prevents myopia. The starting point for their study was a rare form of severe myopia in patients who have a mutation in LRP2 gene, encoding a receptor LRP2 in the retina. Scientists were also able to observe greatly enlarged eyes in mice lacking this LRP2 gene.

Working together with eye specialists of the Toronto Western Research Institute in Canada, and the Freie Universität Berlin, Dr. Christ, Prof. Willnow and their colleagues at MDC pursued the question of why a mutation in the LRP2 gene leads to uncontrolled growth of the mammalian eye.

In a study published by the renowned scientific journal Developmental Cell, they now report that LPR2 sits in the stem cell niche of the mammalian retina. There, LRP2 ensures that this niche does not become overactive to cause overgrowth of the mammalian eyes. The counterpart for LRP2 in this process is a signaling molecule named Sonic Hedgehog (SHH for short) that triggers growth of stem cells in many tissues.

It has long been known that SHH controls development of the embryonic eye. It does so by stimulating the stem cells in the retina to proliferate and to differentiate into all cells types of the retina including rods and cones. As it turns out, LRP2 is specifically placed at the outer most margin of the retina in mammalian eyes.

There, it intercepts SHH before the growth factor can reach the tip of the stem cell niche. In this way, the stem cells at the edge of the human retina are not stimulated to proliferate and eye growth is blocked. In patients who do not produce a functional LRP2 because the gene is mutated, SHH signals now make their way to the stem cell niche at the margin of the retina. The SHH molecules then activates the cells of this stem cell niche – and the eyeball enlarges greatly.

⃰ LRP2 acts as SHH clearance receptor to protect the retinal margin from mitogenic stimuli
Annabel Christ1*, Anna Christa1, Julia Klippert1, J. Corinna Eule2, Sebastian Bachmann3, Valerie A. Wallace4, Annette Hammes1, and Thomas E. Willnow1*
1Max Delbrück Center for Molecular Medicine, 13125 Berlin, 2Small Animal Clinic, Freie Universität Berlin], 14163 Berlin, 3Institute for Vegetative Anatomy, Charité Universitätsmedizin Berlin, 10117 Berlin, Germany, and 4Toronto Western Research Institute, University Health Network, Toronto, M5T 2S8, Canada
**Correspondence to:
Thomas E. Willnow; Email: willnow@mdc-berlin.de
Annabel Christ; Email: annabel.christ@mdc-berlin.de

Contact:
Barbara Bachtler
Press Department
Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC)
Robert-Rössle-Straße 10
13125 Berlin
Germany
Phone: +49 (0) 30 94 06 - 38 96
Fax: +49 (0) 30 94 06 - 38 33
e-mail: presse@mdc-berlin.de
https://www.mdc-berlin.de/en

Weitere Informationen:

https://www.mdc-berlin.de/45076003/en/news/2015/20151002-big_eyes____mdc_researc...

Barbara Bachtler | Max-Delbrück-Centrum für Molekulare Medizin in der Helmholtz-Gemeinschaft

More articles from Life Sciences:

nachricht New application for acoustics helps estimate marine life populations
16.01.2018 | University of California - San Diego

nachricht Unexpected environmental source of methane discovered
16.01.2018 | University of Washington Health Sciences/UW Medicine

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

Im Focus: A thermometer for the oceans

Measurement of noble gases in Antarctic ice cores

The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Morbid Obesity: Gastric Bypass and Sleeve Gastrectomy Are Comparable

17.01.2018 | Health and Medicine

Researchers identify new way to unmask melanoma cells to the immune system

17.01.2018 | Health and Medicine

Genetic discovery may help better identify children at risk for type 1 diabetes

17.01.2018 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>