Prosem Lecture: Oral Motor and Cranial Muscle Phenotypes in Mouse Models of Down Syndrome

Mar. 27, 2017
12:00 PM – 1:00 PM
B62 Goodnight Hall

Topic: Oral Motor and Cranial Muscle Phenotypes in Mouse Models of Down Syndrome
Presenter: Tiffany J. Glass, MA, CMI, PhD, Postdoctoral Research Associate, UW School of Medicine and Public Health, Department of Surgery

Down syndrome (DS) is associated with developmental differences of oromotor function, which can impact vocal communication, feeding, and swallowing. These impairments in DS can be complex and may involve alterations in underlying muscle systems and craniofacial morphology, as well as other etiologies. Our current research uses two genetically complementary mouse models of DS; Ts65Dn and Dp(16)1Yey, to study oromotor and cranial muscle differences associated with DS. We recently reported reductions in levels of a fast myosin heavy chain (MyHC) 2b isoform in the digastric muscles of Ts65Dn mice. However, the causes and the functional consequences of these MyHC 2b reductions in digastric muscles are currently unknown. Two research directions are currently underway to gather information needed to answer these questions. First, we are using a modified food consistency paradigm to test the hypothesis that cranial muscles in mouse models of DS differ from those of typical mice in that they fail to upregulate MyHC 2b in response to altered functional demands imposed during post-natal transitions from suckling to chewing solid food. Second, work is ongoing to quantify differences in feeding and swallowing-related oromotor performance in Ts65Dn and Dp(16)1Yey as juveniles and as mature adults. Collectively, current findings validate these experimental paradigms for the study of cranial muscle plasticity and function differences in Down syndrome. Characterization of oromotor and cranial muscle perturbations in these models will assist in the rational design of future translational studies for identification of new treatment avenues.