High-fat diet reprograms the epigenome of rat spermatozoa and transgenerationally affects metabolism of the offspring
Authors: Laurène Vetterli
Shashank Gupta
Lars R Ingerslev
Anna Krook
Julie Massart
Ida Donkin
Jonathan M Mudry
Romain Barrès
Thais de Castro Barbosa
Petter S Alm
Rasmus Sjögren
Juleen R Zierath
Morten Rasmussen
Soetkin Versteyhe
Journal: Molecular metabolism (2016)
Discipline: BIOLOGY & BIOCHEMISTRY
Keywords: DNA methylation; Epigenetics; Obesity; Spermatozoa; microRNA.
Affiliations: The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden., The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark., Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden., Department of Molecular Medicine and Surgery, Section of Integrative Physiology, Karolinska Institutet, 171 76 Stockholm, Sweden., Department of Veterinary Disease Biology, University of Copenhagen, 1870 Frederiksberg, Denmark., The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden; Department of Molecular Medicine and Surgery, Section of Integrative Physiology, Karolinska Institutet, 171 76 Stockholm, Sweden., The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark. Electronic address: .

Abstract:  Objectives: Chronic and high consumption of fat constitutes an environmental stress that leads to metabolic diseases. We hypothesized that high-fat diet (HFD) transgenerationally remodels the epigenome of spermatozoa and metabolism of the offspring. Methods: F0-male rats fed either HFD or chow diet for 12 weeks were mated with chow-fed dams to generate F1 and F2 offspring. Motile spermatozoa were isolated from F0 and F1 breeders to determine DNA methylation and small non-coding RNA (sncRNA) expression pattern by deep sequencing. Results: Newborn offspring of HFD-fed fathers had reduced body weight and pancreatic beta-cell mass. Adult female, but not male, offspring of HFD-fed fathers were glucose intolerant and resistant to HFD-induced weight gain. This phenotype was perpetuated in the F2 progeny, indicating transgenerational epigenetic inheritance. The epigenome of spermatozoa from HFD-fed F0 and their F1 male offspring showed common DNA methylation and small non-coding RNA expression signatures. Altered expression of sperm miRNA let-7c was passed down to metabolic tissues of the offspring, inducing a transcriptomic shift of the let-7c predicted targets. Conclusion: Our results provide insight into mechanisms by which HFD transgenerationally reprograms the epigenome of sperm cells, thereby affecting metabolic tissues of offspring throughout two generations. 

Retracted: No

PubPeer comments:
 - Fig. 1B-C : why is mean of control animal weight different in F1 compared to F2 (around 9 g *vs.* around 10 g; about 10% difference)? Because of the low data dispersion, I guess this difference would be significant if a statistical test were applied. - Fig. 2C, F: animals get less weight if fed HFD if parent or grand-parent was fed HFD: is it then advantageous to have an overweight ancestor? - Western blot shown in Fig. 6E: lack of housekeeping protein as a loading control. Why is molecular weight of caspase 9 different in different lanes? Shape of caspase 9 band in PatCd-CD lane indicates lane protein overload. , 
 Thanks a lot for bringing these issues up. I have replied to your questions below and I will be glad to discuss it further. Thais Fig. 1B-C: In Fig 1B it is represented the weight of F1 generation, while in Fig 1C it is the F2 body weight. There are two different groups (generations), therefore the small difference in body weight is not surprising. Additionally, a potential significant statistical difference between F1 and F2 control animals is not relevant to the conclusion represented in these figures. Fig. 2C: It would potentially be a benefit to have an overweighed ancestor, since one would get less weight if fed HFD. However, despite the lower weight, these animals were slightly more glucose intolerant than the animals from chow-fed ancestors. Therefore, there is no real advantage, since these animals are metabolically disturbed. Western blot shown in Fig. 6E: The absence of a housekeeping protein in the figure is because we used Ponceau staining of the membranes as loading controls. That was a quite large picture to upload to the article. The different shape of Cas9 band in the second PatCD-CD sample may indicate protein overload in this lane. Indeed, the Casp9 band shows different pattern in all HFD samples. We do not have an explanation for that. ,