Composition of protein solution plays a definite role in cataract formation

Cataracts are the most common eye disease in humans. However, the exact processes leading to this condition are not understood.

A team of researchers with the Technical University of Munich (TUM) has now discovered that the composition of the protein solution plays a definite role. Their conclusions are contrary to popular opinion in the field.

The cells in the lens contain a fully concentrated protein solution that is normally clear.

When the balance of proteins in the lens is destroyed, they accumulate together and the lens clouds. “

Johannes Buchner, Professor, Chair of Biotechnology, Technical University of Munich

This leads to a condition called cataracts.

The cloud can have different causes. Because the proteins in the lens are formed in the embryo and are not replaced, damage can accumulate over the years, ultimately causing the lens to cloud over. That is why cataracts occur mostly in the elderly. But there are some individuals in terms of genetic predisposition to the state of the eye, in which proteins in the lens move. In these cases, cataracts are present at birth or appearing during childhood.

Unsaturated proteins were eliminated immediately

The scientists studied sequences of mice affected by hereditary cataracts. They worked with the research group around Jochen Graw, an expert on eye lenses who until 2019 was a professor at the Institute of Developmental Genetics at Helmholtz Zentrum Munich.

So far, the conventional view stated that only the deficient proteins in the eye react with each other and form lumps. But Buchner’s team has now shown that in mice with “genetic cataracts”, this was not the case. “We found that the unstable, unstable proteins in the lens did not exist,” Buchner said. “They are immediately eliminated.” Instead the ‘healthy’ proteins fall together. “Our model, based on these new insights, states that the balance between the different proteins, or their ratios to each other, is important. When one of these components is missing, those is left to interact and form lumps. “

An important step for cataract treatment

Many studies have been done to understand the causes of cataracts. “But the lenses in mice have never been so thoroughly studied, comparing wild populations with mutants,” Buchner says. The new insights are an important step in finding new treatments for cataracts. Surgery is the most common method, in which artificial lenses are inserted into the eye.

“If you understand exactly what’s going on, you can also think of possible ways to use medication to prevent the bad interactions,” Buchner says. “But we have a long way to go – and first we need to show that the proposed model also applies to the lens in the human eye.”