Elsevier

Molecular Metabolism

Volume 5, Issue 12, December 2016, Pages 1162-1174
Molecular Metabolism

Original Article
Dietary fat and gut microbiota interactions determine diet-induced obesity in mice

https://doi.org/10.1016/j.molmet.2016.10.001Get rights and content
Under a Creative Commons license
open access

Highlights

  • Cholesterol-based but not plant sterol-based high-fat diet protects germfree (GF) mice from diet-induced obesity (DIO).

  • DIO resistant GF mice show preferential carbohydrate oxidation, higher energy expenditure and energy and fat excretion.

  • DIO resistance in GF mice is accompanied by increased steroid hormone levels but decreased bile acid levels in the cecum.

  • Substrate oxidation and fat excretion in DIO resistant GF mice is linked to decreased hepatic Cyp7a1 and Nr1h4 expression.

Abstract

Objective

Gut microbiota may promote positive energy balance; however, germfree mice can be either resistant or susceptible to diet-induced obesity (DIO) depending on the type of dietary intervention. We here sought to identify the dietary constituents that determine the susceptibility to body fat accretion in germfree (GF) mice.

Methods

GF and specific pathogen free (SPF) male C57BL/6N mice were fed high-fat diets either based on lard or palm oil for 4 wks. Mice were metabolically characterized at the end of the feeding trial. FT-ICR-MS and UPLC-TOF-MS were used for cecal as well as hepatic metabolite profiling and cecal bile acids quantification, respectively. Hepatic gene expression was examined by qRT-PCR and cecal gut microbiota of SPF mice was analyzed by high-throughput 16S rRNA gene sequencing.

Results

GF mice, but not SPF mice, were completely DIO resistant when fed a cholesterol-rich lard-based high-fat diet, whereas on a cholesterol-free palm oil-based high-fat diet, DIO was independent of gut microbiota. In GF lard-fed mice, DIO resistance was conveyed by increased energy expenditure, preferential carbohydrate oxidation, and increased fecal fat and energy excretion. Cecal metabolite profiling revealed a shift in bile acid and steroid metabolites in these lean mice, with a significant rise in 17β-estradiol, which is known to stimulate energy expenditure and interfere with bile acid metabolism. Decreased cecal bile acid levels were associated with decreased hepatic expression of genes involved in bile acid synthesis. These metabolic adaptations were largely attenuated in GF mice fed the palm-oil based high-fat diet. We propose that an interaction of gut microbiota and cholesterol metabolism is essential for fat accretion in normal SPF mice fed cholesterol-rich lard as the main dietary fat source. This is supported by a positive correlation between bile acid levels and specific bacteria of the order Clostridiales (phylum Firmicutes) as a characteristic feature of normal SPF mice fed lard.

Conclusions

In conclusion, our study identified dietary cholesterol as a candidate ingredient affecting the crosstalk between gut microbiota and host metabolism.

Keywords

Germfree
Energy balance
Diet-induced obesity resistance
High-fat diet

Abbreviations

Abcg5
ATP-binding cassette sub-family G member 5
Abcg8
ATP-binding cassette sub-family G member 8
Actb
beta actin
Akr1d1
aldo-keto-reductase family member 1
ANOVA
analysis of variance
BMR
basal metabolic rate
CD
control diet
CA
cholic acid
CDCA
chenodeoxycholic acid
CIDEA
cell death inducing DFFA-like effector
COX4
cytochrome c oxidase subunit 4
Cyp7a1
cholesterol 7 alpha-hydroxylase
Cyp27a1
cholesterol 27 alpha-hydroxylase
DCA
deoxycholic acid
Dhcr7
7-dehydrocholesterol reductase
DIO
diet-induced obesity
DEE
daily energy expenditure
Eef2
eukaryotic elongation factor 2
FT-ICR-MS
Fourier transform-Ion Cyclotron Resonance-Mass Spectrometry
FT-IR
Fourier transform-infrared spectroscopy
GF
germfree
GUSB
beta-glucuronidase
HDCA
hyodeoxycholic acid
Hmgcr
3-hydroxy-3-methylglutaryl Coenzyme A reductase
Hmgcs
3-hydroxy-3-methylglutaryl Coenzyme A synthase 1
HP
heat production
Hprt1
hypoxanthine guanine phosphoribosyl transferase
Hsd11b1
hydroxysteroid (11-β) dehydrogenase 1
Hsp90
heat shock protein 90
Ldlr
low density lipoprotein receptor
LHFD
high-fat diet based on lard
MCA
muricholic acid
Nr1h2
nuclear receptor subfamily 1, group H, member 2 (liver X receptor β)
Nr1h3
nuclear receptor subfamily 1, group H, member 3 (liver X receptor α)
Nr1h4
nuclear receptor subfamily 1, group H, member 4 (farnesoid X receptor α)
PHFD
high-fat diet based on palm oil
PRDM16
PR domain containing 16
qPCR
quantitative real-time polymerase chain reaction
SPF
specific pathogen free
Srebf1
sterol regulatory element binding transcription factor 1
TCA
taurocholic acid
Tf2b
transcription factor II B
TMCA
Tauromuricholic acid
UCP1
uncoupling protein 1
UDCA
ursodeoxycholic acid
UPLC-TOF-MS
ultraperformance liquid chromatography-time of flight-mass spectrometry

Cited by (0)

8

Current address: Department for Vascular and Endovascular Surgery, Technical University of Munich, Ismaningerstraβe 22, 81675 München, Germany.