SEMINAR: Influence of IGF-1 and myostatin on post-natal growth and aging

The Seminar: Chris will present an overview from a biomedical and agricultural perspective of studies done in his lab on the growth hormone, insulin-like growth factor 1 and myostatin, which form part of a common axis (GH/IGF-1/Mstn) that regulates growth, maintenance and aging of the body. Knowing that IGF-1 stimulates, while myostatin inhibits growth, Chris and colleagues crossed Mstn-/- mice with a transgenic line in which IGF-1 is overexpressed in skeletal muscle to generate offspring differing in copy number for both genes. Mice that had no myostatin and additional IGF-1 were twice the size and had 3.5 times the amount of muscle mass to that of wild-type controls. In a second cohort, those with additional IGF-1 died at a younger age. While the causative factors mediating the actions of IGF-1 of aging remain unclear, the recent discovery that the deacetylase sirtuin 6 (Sirt6) and Klotho regulate aging in mammals was a breakthrough in the search for a mechanism. Chris will show that IGF-1 regulates the expression of Klotho and Sirt6 in skeletal muscle. Finally, Chris will present the discovery of a novel splice-variant of myostatin that stimulates myogenesis and that may have an additional role to play in the development of double-muscling in breeds like Belgian Blue cattle.

The Speaker: Chris is a growth physiologist at AgResearch Ruakura. He completed a PhD at Agresearch Invermay studying the seasonal growth of red deer, then completed two postdoctoral positions in the United States. The first at Auburn University (Alabama) addressed the mechanisms underlying how illness and disease reduces appetite and growth of sheep and cattle. The second at Michigan State University addressed the role of factors that regulate the growth axis in cattle. Chris is a senior scientist and, until recently, led the Growth and Lactation research team. His current research focuses on the role of growth hormone, IGF-1 and myostatin in regulating the post-natal growth of livestock, the development of marbling and the eating quality of meat. A further interest is in the regulation of antler growth. He is the current president of the NZ Society of Endocrinology.