Localisation and interactome analysis of dystrophin isoforms in the mouse brain

Topic:

Pre-Clinical Research

Poster Number: S32

Author(s):

Konstantina Tetorou, PhD, University College London, Artadoht Aghaeipour, University College London, Talia Gileadi, PhD, University College London, Pablo Perdomo Quinteiro, Leiden University Medical Center, Liwen Zhang, PhD, Mass Spectrometry and Proteomics Facility, Ohio State University, Pietro Spitali, PhD, Leiden University Medical Center, Jennifer Morgan, PhD, University College London, Federica Montanaro, PhD, University College London, Francesco Muntoni, FRCPCH, FMedSci, University College London, National Institute for Health Research Great Ormond Street Hospital

Background: Duchenne muscular dystrophy (DMD) is a severe neuromuscular disease caused by mutations in the dystrophin gene, resulting in muscle degeneration and a shortened life expectancy. DMD patients also have a higher prevalence of intellectual disability, anxiety, attention deficit hyperactivity disorder, and autism spectrum disorder than the general population. The presence of at least seven alternative promoters, two polyA addition sites and multiple alternative splicing results in several dystrophin isoforms with different expression patterns and putative roles. Mutations affecting only the full-length isoforms (Dp427) have been linked to emotional behavioural problems including anxiety, depression, and hyperactivity in DMD patients. DMD mouse models, that carry a mutation affecting Dp427 dystrophin isoforms display an enhanced fear response, and increased anxiety- and depressive-like behaviours. We hypothesised that dystrophin isoforms have differential expression in different brain areas and that their deficiency results in the different comorbidities present in patients.
Objectives: The aims of this study were to investigate the different dystrophin isoforms localisation in mouse brain and identify potential candidate dystrophin protein interactors in the mouse brain. To do this, we used mdx5cv mice lacking Dp427 and mdx52 mice lacking both Dp427 and Dp140.
Results: Our results revealed that Dp427c expression is high in the cortex, while Dp427p1 and Dp427p2 are highly expressed in the cerebellum as demonstrated in capillary western blot analysis. Mdx52 and mdx5cv mice had very low Dp427 transcript levels, due to the mRNA being partially transcribed or increased decay, while neither of these mdx mouse models expressed Dp427 protein. Additionally, mass spectrometry analysis indicated that different proteins interact differently with Dp427, Dp140 and Dp71 in cortex, hippocampus, cerebellum, midbrain and olfactory bulbs of mouse brains.
Conclusions: Thus, this newfound knowledge will address the molecular networks associated with emotional and cognitive comorbidities in DMD.