The Neurogenetics working group headed by Hans Gerd Nothwang is researching deafness genes. The scientists have now published their findings in the renowned Journal of Biological Chemistry. They show that Deafness genes fulfil an extremely important function for the hearing process.
Electronic inner ear prostheses are a great hope for deaf people and people with profound hearing loss. However, they do not always lead to success. Research by the Neurogenetics working group led by Prof Dr Hans Gerd Nothwang promises to provide a better assessment of their benefits.
Under the title "Time-dependent gene expression analysis of the developing superior olivary complex", their research results have now been published in the renowned Journal of Biological Chemistry.
The loss of the deafness gene Cacnad not only brings the function of the inner ear to a standstill, but also significantly impairs the central nervous processing of acoustic information - as the Oldenburg scientists were able to demonstrate a year ago. Hearing aids are not yet able to compensate for such a defect. "Whether disorders of the central nervous auditory pathway caused by deafness genes occur more frequently than previously assumed is a clinically very relevant question. To answer it, we first examined the genetic programme of an area of the brain that is important for the auditory pathway. We then compared this with that of the inner ear," explains Nothwang.
The scientists worked together with Prof. Dr Olaf Bininda-Emonds, a professor of molecular systematics at the University of Oldenburg with experience in analysing large amounts of data. With his support, the hearing researchers were able to identify an important class of genes that enable and influence the expression of genes.
The analyses revealed: There is a close connection between the genetic programme of the inner ear and the auditory pathway. "The finding that numerous genes associated with deafness in the inner ear are also strongly expressed in the auditory pathway and probably fulfil an important function there is particularly important," explains Nothwang. Statistical analyses carried out by the hearing researchers with the help of Prof. Dr Alexander Hartmann's "Computer-Oriented Theoretical Physics" working group revealed the following: Deafness genes in the auditory pathway showed a statistically significant increase in gene expression compared to the brain as a whole.
"These results support our hypothesis that deafness genes also fulfil an extremely important function for the central nervous hearing process," says Nothwang. Nothwang therefore hopes that a deeper insight into the functions of deafness genes will improve the use of hearing aids. Technological advances in human genetic diagnosis would make it possible in the foreseeable future to identify the underlying genetic mutation for patients with hearing impairment. In conjunction with data on the function of the individual genes, it would then be possible to estimate which deficits are present in the auditory pathway. This represents an important step towards individually tailored therapy.
"We will therefore continue our investigations into the function of deafness genes in the auditory pathway in the Research Training Group 'Molecular Basis of Sensory Biology' and in the Hearing4all cluster of excellence," emphasises Nothwang. These investigations are an ideal complement to other projects of the Oldenburg cluster of excellence Hearing4all, which focus, among other things, on the further development of central nervous implants.
Heike Ehmann, Heiner Hartwich, Christian Salzig, Nadja Hartmann, Mathieu Clement-Ziza, Kathy Ushakov, Karen B. Avraham, Olaf R. P. Bininda-Emonds, Alexander K. Hartmann, Patrick Lang, Eckhard Friauf and Hans Gerd Nothwang: "Time-dependent gene expression analysis of the developing superior olivary complex", in: J. Biol. Chem. jbc.M113.490508. First Published on July 26, 2013, doi:10.1074/jbc.M113.490508