Coordinated regulatory variation associated with gestational hyperglycaemia regulates expression of the novel hexokinase HKDC1
Cong (Karl) Guo, Anton E. Ludvik, Michelle E. Arlotto, M. Geoffrey Hayes, Loren L. Armstrong, Denise M. Scholtens, Christopher D. Brown, Christopher B. Newgard, Thomas C. Becker, Brian T. Layden, William L. Lowe & Timothy E. Reddy
Maternal glucose levels during pregnancy impact the developing fetus, affecting metabolic health early and later in life. Both genetic and environmental factors influence maternal metabolism, but little is known about the genetic mechanisms that alter glucose metabolism during pregnancy. Here we report that haplotypes previously associated with gestational hyperglycemia in the third trimester disrupt regulatory element activity and reduce expression of the nearby HKDC1 gene. We further find that experimentally reducing or increasing HKDC1 expression reduces or increases hexokinase activity, respectively, in multiple cellular models; and that purified HKDC1 protein has hexokinase activity in vitro. Together, these results suggest a novel mechanism of gestational glucose regulation in which the effects of genetic variants in multiple regulatory elements alter glucose homeostasis by coordinately reducing expression of the novel hexokinase HKDC1.