News Article

More than just retinal glue: research conducted into the proteome of Müller cells

Müller glial cells are the major glial component of the retina. Up to now, however, the protein composition of these cells was unclear, due to the lack of suitable enrichment methods. A research team at the Helmholtz Zentrum München has now found a way to overcome this methodological obstacle. Their findings, which have been published in the journal Molecular & Cellular Proteomics, could help to improve our understanding of various eye diseases in the future.

A DNA “control error” increases the risk of type 2 diabetes. This knowledge is based on a new process which has enabled researchers to compare DNA sequences in different species. (Source: Michael Pütz Design Print)
Dr. Stefanie Hauck. Photo: HMGU

Müller cells are a type of glial cells or glia (Greek for “glue”) found in the retina. They are responsible for maintaining the stability of the retina and for providing mechanical support for the neurons, which pick up and transmit visual stimuli. Furthermore, Müller cells are thought to protect against free radicals and to play a part in the blood-retinal barrier. Up to now it has not been possible to fully elucidate their role, as it is very difficult to devise a method for isolating and enrichingthose large and arborized cells in their intact, native from.

In order to tackle this problem, the team of scientists led by Dr. Stefanie Hauck from the Research Unit Protein Science along with experts from the University of Regensburg developed a special protocol to aid them in enriching cells without damaging or polluting with other cells such as neurons. To this end, the entire retina was enzymatically digested into individual cells, and the Müller cells were then marked with the aid of a specific antibody (anti-Integrin beta 1 ) and sorted mechanically. “That all has to be done very gently as otherwise the cells become spherical and lose all of their proteomically interesting cell arborisations,” explains Stefanie Hauck.

“Using the new method we were able for the first time to create the protein profile of  physiologically intact glial cells of the retina,” says first author Antje Grosche, summing up the results. “To do so, we only needed between 200,000 and 500, 000 cells, which are relatively small amounts in this context.” Amongst the analyzed proteins, the researchers discovered numerous new candidates that could become suitable markers for Müller cells. Moreover, the team gained insights into how the cells adapt to their environment and develop new functions. For example, the researchers found proteins which suppress inflammation, which are required to form blood vessels or which act as anti-oxidative enzymes.

Dr. Stefanie Hauck also sees the medical potential:  “With all neurodegenerative diseases of the retina the involvement of the glial cells is described. However, up to now, it has not been widely understood what this contribution is. Our study provides the basis for understanding the role of the glial cells in connection with diseases such as diabetic retinopathy and age-related or inflammatory degenerative diseases.”

Further Information

Original publication:
Grosche, A. et al. (2015). The proteome of native adult Müller glial cells from murine retina, Molecular & Cellular Proteomics
doi: 10.1074/mcp.M115.052183 

Link to publication

Dr. Stefanie Hauck
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