Janssen and ECU Muscle Collaboration for 2015-2016 Grant uri icon

abstract

  • For the next year of the collaboration we propose expansion of the study to: 1) further characterize the muscle culture system with regard to its metabolic profile, particularly comparing insulin sensitive vs. insulin resistant primary biopsies to the differentiated myotubes from the same donors, to understand whether the phenotype of the primary biopsy material is retained in the myotube system. Successful completion of Aim 1) would be a) the observation of a strong correlation between the phenotype of the primary biopsy material and the phenotype of the cultured cells; and b) a correlation between the insulin sensitivity of the subject, the phenotype of the biopsy, and the phenotype of the cultured material. This would indicate that the culture system is reflective of the relative insulin sensitivity of the human subject. Based on success in Aim 1) above, in subsequent year(s), we may propose to 2) evaluate its suitability for identification of potential drug discovery targets in human skeletal muscle, specifically the delineation of specific transcriptional signals that would clearly differentiate insulin sensitive vs. insulin resistant-derived muscle cells, and enable genetic or pharmacologic screens to identify proteins or molecules that can modulate the transcriptomic and potentially the metabolic profile of these cells. In support of these goals, for the coming year, we propose to A) at ECU, compare the metabolic profile (glucose/pyruvate oxidation, fatty acid oxidation and insulin signaling) in primary biopsy material from insulin sensitive vs. insulin resistant subjects, to the profile observed upon differentiation of the primary myoblasts into myotubes from the same sample (same subject). Ideally the biopsy material will be of sufficient size that some metabolic profiling as well as myoblast culture can be achieved from the same biopsy sample, and the insulin sensitivity of the subject is known. If successful this effort will further strengthen the relationship between the insulin sensitivity of the subject and the phenotype of the muscle biopsy and subsequently cultured material. As a component of A), in order to assess whether there are molecules that can convert an insulin-resistant phenotype to that which is insulin-sensitive, we propose to test whether treatment with an AMP-kinase activator will convert the phenotype of insulin resistant myotubes to that of insulin sensitive myotubes, and As a component of A) we also propose to test if the low activity of the TCA cycle in insulin resistant cells is due to a low rate of anaplerosis. B) establish both the culture model as well as the metabolic (glucose and fatty acid oxidation) assays at Janssen Spring House. The system would then be validated for potential use in future transcriptional profiling and screening, by confirming the phenotypes previously observed, specifically a reduced glucose and fatty acid oxidation profile or altered insulin signaling in insulin resistant vs. insulin sensitive -derived muscle myotubes. As a component of B) we propose to test whether treatment with an AMP-kinase activator will convert the phenotype of insulin resistant muscle cells to that of lean insulin sensitive muscle cells.

date/time interval

  • August 2015 - August 2017