Slide 1: Methyl donors and epigenetic regulation of the early embryo
5/1/20 Methyl donors and epigenetic regulation of the early embryo P.J. Hansen Dept. of Animal Sciences University of Florida Take-home messages • Changing DNA methylation during the earliest stages of life, when the embryo is developing from the one-cell stage to the blastocyst stage (day 7 in the
Slide 2: DNA methylation is an example of epigenetics
5/1/20 DNA methylation is an example of epigenetics: inherited change in gene function without change in gene sequence methylation Environment of the cell can control DNA methylation and DNA demethylation inherited demethylation Daughter cells/transgenerational MUSCLE myoglobin MYOGLOBIN b-casein MA
Slide 3: DNA methylation in bovine embryos
5/1/20 Take-home messages • Changing DNA methylation during the earliest stages of life, when the embryo is developing from the one-cell stage to the blastocyst stage (day 7 in the cow), can change the program of development to affect postnatal phenotype • Providing methyl donors is one way to chang
Slide 4: Example of aberrant programming: large offspring syndrome
5/1/20 Day 21 Consequences of Being Born From a Mother Fed a Low Protein Diet During the Preimplantation Period (Watkins et al., Biol. Reprod. 78:299 (2008) Mating (Day 0) NPD Emb-LPD 18% casein 9% casein Both groups 18% casein Raised until 28 d of age EXAMPLE OF ABERRANT PROGRAMMING LARGE OFFSPRING
Slide 5: Calf birth weight and placenta comparison, IVF
5/1/20 98 kg at birth picture at 2 days of age 8722 – IVF Dried placenta weight – 9.1 g Cotyledon diameter – 3.5 cm Fetal weight – 152 g Liver weight – 6.6 g Heart weight - 1.4 g 7348 – IVF + CSF2 Dried placenta weight – 34.1 g Cotyledon diameter – 5.6 cm Fetal weight – 354.3 g Liver weight – 18.6 g
Slide 6: Take-home messages
5/1/20 Take-home messages • Changing DNA methylation during the earliest stages of life, when the embryo is developing from the one-cell stage to the blastocyst stage (day 7 in the cow), can change the program of development to affect postnatal phenotype • Providing methyl donors is one way to chang
Slide 7: Agouti methylation example
5/1/20 Agouti active inactive Methylation of agouti locus http://learn.genetics.utah.edu/content/epigenetics/nutrition/ Epigenomics 6:447 (2014) 7
Slide 8: Choline and methyl group metabolism
5/1/20 methylation DNA methyltransferase SAM S-adenosyl methionine SAH S-adenosyl-homocysteine Acetylcholine = methyl group acetylation CHOLINE phosphorylation oxidation Tetrahydrofolate Dimethylglycine Phosphocholine Betaine Aldehyde Sarcosine Sarcosine Homocysteine Betaine Methyl-TH-folate CDP-Cho
Slide 9: Does feeding of choline program the embryo to affect the calf?
5/1/20 Take-home messages • Changing DNA methylation during the earliest stages of life, when the embryo is developing from the one-cell stage to the blastocyst stage (day 7 in the cow), can change the program of development to affect postnatal phenotype • Providing methyl donors is one way to chang
Slide 10: Choline metabolism pathway
5/1/20 Acetylcholine = methyl group acetylation CHOLINE phosphorylation oxidation Tetrahydrofolate Dimethylglycine Phosphocholine Betaine Aldehyde Sarcosine Sarcosine Homocysteine Betaine Methyl-TH-folate CDP-Choline Dimethylglycine Tetrahydrofolate (used for methyl-THF) Methionine Phosphatidylcholi
Slide 11: Choline effects on embryo development
5/1/20 Choline effects on embryo development Criteria for concentration selection [Choline chloride] Sodium Chloride Oocytes Control 0.00 mM 6.37 mM Total concentration of free choline in plasma 0.004 mM 6.37 mM of lactating dairy cows at week 1 postpartum Insemination Total concentrations of cholin
Slide 12: Global DNA methylation in blastocysts
5/1/20 Global DNA methylation in blastocysts 1 .5 0 Im m u n o r e a c t iv e f o r 5 - m e t h y lc y t o s in e P < 0 .0 0 0 1 c 1 .2 5 b ab a ( In t e n s it y r a t io ) 1 .0 0 0 .7 5 0 .5 0 0 .2 5 0 .0 0 0 .0 m M 0 .0 0 4 m M 1 .3 m M 1 .8 m M C h o lin e c o n c e n t r a t io n Fluorescence f
Slide 13: Choline effects on establishment of pregnancy and offspring phenotype
5/1/20 Fluorescence for lipids in blastocysts 800 P = 0 .0 1 3 9 b b F lu o r e s c e n c e in t e n s it y ab 600 a 400 200 0 0 .0 m M 0 .0 0 4 m M 1 .3 m M 1 .8 m M C h o lin e c o n c e n t r a t io n Choline effects on establishment of pregnancy and phenotype of offspring Donors OPU Oocyte In vi
Slide 14: Gestation length
5/1/20 Choline effects on establishment of pregnancy and phenotype of offspring Embryo Pregnancy Birth weight transfer diagnosis Vehicle n=57 ET 28 d after ET Choline n=43 ET Statistical analysis - For embryo development and pregnancy rate, proc Glimmix binary distribution, treatment and sire effect
Slide 15: Birthweight of calves
5/1/20 Birthweight of calves (adj for gestation length) B Treatment P=0.0449 60 Sex P=0.6838 Treatment*Sex P=0.6672 Body weight at birth, kg 50 Sex Treatment Birth weight, kg Females n=13 Vehicle 36.4 ± 1.9 40 Females n=11 Choline 41.2 ± 2.2 Males n=9 Vehicle 34.5 ± 2.4 30 Males n=6 Choline 41.0 ± 2
Slide 16: P = G + E; Acknowledgements
5/1/20 P = phenotypic variation G = genetic variation E = environmental variation P=G+E Weaning weight Weight gain Litter size Fertility Disease resistance Identify genetically superior Identify modifications in individuals & propagate them the animal’s environment (nutrition, photoperiod, Milk yiel
Slide 17: hansen@animal.ufl.edu
5/1/20 @ufpjhansen hansen@animal.ufl.edu 17