TY - JOUR
T1 - Glucose transporter 8 (GLUT8) regulates enterocyte fructose transport and global mammalian fructose utilization
AU - DeBosch, Brian J.
AU - Chi, Maggie
AU - Moley, Kelle H.
PY - 2012/9/1
Y1 - 2012/9/1
N2 - Enterocyte fructose absorption is a tightly regulated process that precedes the deleterious effects of excess dietary fructose in mammals. Glucose transporter (GLUT)8 is a glucose/fructose transporter previously shown to be expressed in murine intestine. The in vivo function of GLUT8, however, remains unclear. Here,wedemonstrate enhanced fructose-induced fructose transport in both in vitro and in vivo models of enterocyte GLUT8 deficiency. Fructose exposure stimulated [ 14C]-fructose uptake and decreased GLUT8 protein abundance in Caco2 colonocytes, whereas direct short hairpin RNA-mediated GLUT8 knockdown also stimulated fructose uptake. To assess GLUT8 function in vivo,we generated GLUT8-deficient (GLUT8KO) mice. GLUT8KO mice exhibited significantly greater jejunal fructose uptake at baseline and after high-fructose diet (HFrD) feeding vs. wild-type mice. Strikingly, long-term HFrD feeding in GLUT8KO mice exacerbated fructose-induced increases in blood pressure, serum insulin, low-density lipoprotein and total cholesterol vs. wild-type controls. Enhanced fructose uptake paralleled with increased abundance of the fructose and glucose transporter, GLUT12, in HFrD-fed GLUT8KO mouse enterocytes and in Caco2 cultures exposed to high-fructose medium. We conclude that GLUT8 regulates enterocyte fructose transport by regulating GLUT12, and that disrupted GLUT8 function has deleterious long-term metabolic sequelae. GLUT8 may thus represent a modifiable target in the prevention and treatment of malnutrition or the metabolic syndrome.
AB - Enterocyte fructose absorption is a tightly regulated process that precedes the deleterious effects of excess dietary fructose in mammals. Glucose transporter (GLUT)8 is a glucose/fructose transporter previously shown to be expressed in murine intestine. The in vivo function of GLUT8, however, remains unclear. Here,wedemonstrate enhanced fructose-induced fructose transport in both in vitro and in vivo models of enterocyte GLUT8 deficiency. Fructose exposure stimulated [ 14C]-fructose uptake and decreased GLUT8 protein abundance in Caco2 colonocytes, whereas direct short hairpin RNA-mediated GLUT8 knockdown also stimulated fructose uptake. To assess GLUT8 function in vivo,we generated GLUT8-deficient (GLUT8KO) mice. GLUT8KO mice exhibited significantly greater jejunal fructose uptake at baseline and after high-fructose diet (HFrD) feeding vs. wild-type mice. Strikingly, long-term HFrD feeding in GLUT8KO mice exacerbated fructose-induced increases in blood pressure, serum insulin, low-density lipoprotein and total cholesterol vs. wild-type controls. Enhanced fructose uptake paralleled with increased abundance of the fructose and glucose transporter, GLUT12, in HFrD-fed GLUT8KO mouse enterocytes and in Caco2 cultures exposed to high-fructose medium. We conclude that GLUT8 regulates enterocyte fructose transport by regulating GLUT12, and that disrupted GLUT8 function has deleterious long-term metabolic sequelae. GLUT8 may thus represent a modifiable target in the prevention and treatment of malnutrition or the metabolic syndrome.
UR - http://www.scopus.com/inward/record.url?scp=84865420518&partnerID=8YFLogxK
U2 - 10.1210/en.2012-1541
DO - 10.1210/en.2012-1541
M3 - Article
C2 - 22822162
AN - SCOPUS:84865420518
VL - 153
SP - 4181
EP - 4191
JO - Endocrinology
JF - Endocrinology
SN - 0013-7227
IS - 9
ER -