Effects of dietry nicin supplementtion on heptic expression of FoxO nd genes involved in glucose production in diry cows during the trnsition period A. Kinoshit, L. Locher, R. Tienken 3, U. Meyer 3, S. Dänicke 3, J. Rehge 4, K. Huber 5 Deprtment of Physiology, University of Veterinry Medicine Hnnover, Foundtion, Hnnover, Germny Clinic for Ruminnts with Ambultory nd Herd Helth Services t the Center of Veterinry Clinicl Medicine, Ludwig-Mximilins- University Munich, Germny 3 Institute of Animl Nutrition, Federl Reserch Institute for Animl Helth, Friedrich-Loeffler-Institute, Brunschweig, Germny 4 Clinic for Cttle, University of Veterinry Medicine Hnnover, Foundtion, Hnnover, Germny 5 Institute of Animl Science, University of Hohenheim, Stuttgrt, Germny
Bckground Forkhed box protein O (FoxO) Trnscriptionl fctor for G6P, PCK (Brthel et l., 5) Inctivted by phosphoryltion s trget of insulin signling (Brthel et l., 5)
Bckground glucose output Glucose G6P Glucose-6-P gluconeogenesis PEP PCK OAA pfoxo (inctive) Mlte PEP OAA Propionte phosphoryltion Insulin FOXO (ctive) PCK, G6P Gene expression Nucleus Mitochondri Cytosol Pyruvte Alnine 3
Bckground Forkhed box protein O (FoxO) Trnscriptionl fctor for G6P, PCK(Brthel et l., 5) Inctivted by phosphoryltion s trget of insulin signling (Brthel et l., 5) Nicotinic cid (NA) Substrte for NAD, NADH (Niehoff et l., 9) Lipid-lowering effect (Pires et l., 9, Titgemeyer et l.,, Kenez et l., 4) Affects trnsltionl nd trnscriptionl regultion (Khn et l., 3, 3) Reduced phosphoryltion of FoxO in rts (Choi et l, ) 4
Hypothesis & ims Hypothesis: NA supplements nd onset of lcttion ffect FoxO-medited regultion of heptic glucose production nd the expression of downstrem genes in diry cows in trnsition period Aimes: To investigte the effects of dietry NA supplements nd onset of lcttion on expression nd extent of phosphoryltion of FoxO s well s of genes involved in glucose metbolism in diry cows in trnsition period fed with diet with high or low concentrte portions 5
Study design pluriprous Germn Holstein cows Nicotinic cid (NA) supplementtion (d-4 d+) NA (4g/dy; N=) Control (g/dy; N = ) 6
Concentrte proportion (%) Study design pluriprous Germn Holstein cows : HC-CON, HC-NA : LC-CON, LC-NA NA supplementtion 4g/dy 6 5 3-4 - 7 6 dys relted to clving X Liver biopsy X Liver biopsy X Liver biopsy 7
Study design pluriprous Germn Holstein cows Preprtum: LOW concentrte proportion (3% in DM bsis) Preprtum: HIGH concentrte proportion (6% in DM bsis) Anlysis of liver biopsy smples Protein expression (Western Blot) tfoxo: Totl protein of FoxO pfoxo: Extent of phosphoryltion of FoxO t serine 56 (rel time-qpcr) FoxO Insulin Receptors (IRA, IRB) GLUT G6P, PCK, PC, PCCA Dt evlution SAS mixed model for repeted mesures for effects of NA, time, nd concentrte Nicotinic cid (NA) supplementtion (d-4 d+) NA (4g/dy) LC-NA (n=5) HC-NA (n=6) Control (g/dy) LC-CON (n=5) HC-LOW (n=5) 8
Protein expression FoxO Protein nd LC-CON HC-CON LC-NA HC-NA 8 6 Totl FoxO Protein.4. FoxO mrna 4.8 8.6 6 4.4. d-4 d d d-4 d d Time NA Concentrte : n.s. : n.s. : n.s. 9
Extent of phsophoryltion Extent of phosphoryltion of FoxO t ser56 LC-CON HC-CON LC-NA HC-NA 3..5..5..5. d-4 d d Time NA Concentrte NA x Concentrte NA x Concentrte x time :.8 : n.s. : n.s. :.4 :.8
of gluconeogenic enzymes.5 Time:<. NA x time:.9 PCK.5 Time:<. NA x time:. G6P ** b -CON (n = ) -NA (n = ).5.5 d-4 d d d-4 d d 3.5.5.5 Time: <. Time x NA: n.s. PC d-4 d d.5.5 Time:<. NA x time:.4 PCCA * d-4 d d b
.5 Time: n.s. NA x time:<. GLUT * b b * -CON (n = ) -NA (n = ).5 d-4 d d.5 Time: <. NA x time: n.s. IRA.5 Time:.4 NA x time: <. IRB b ** b.5.5 d-4 d d d-4 d d
Summry glucose output GLUT phosphoryltion pfoxo Glucose tfoxo G6P No effect by time nd diet FOXO Glucose-6-P PEP gluconeogenesis PCK OAA Mlte PEP OAA PC Mitochondri Up-regultion by NA t d PCCA Propionte Pyruvte Insulin Down-regultion by NA t d Nucleus Cytosol IRA IRB Insulin signling Alnine protein mrna 3
Conclusion NA supplements ppered to induce reduced insulin sensitivity nd incresed heptic gluconeogenesis in diry cows in trnsition period Preprtl concentrte portion in the diet hd only mrginl effect on the NA ction on gene expression Regultion of heptic gluconeogenesis by FoxO ppered to be less importnt t the levels of trnscription, trnsltion nd phosphoryltion 4
Thnk you for your ttention This study ws supported by Deutsche Forschungsgemeinschft 5