Gut microbiome responds to alteration in female sex hormone status and exacerbates metabolic dysfunction

Abstract

Women are at significantly greater risk of metabolic dysfunction after menopause, which subsequently leads to numerous chronic illnesses. The gut microbiome is associated with obesity and metabolic dysfunction, but its interaction with female sex hormone status and the resulting impact on host metabolism remains unclear. Herein, we characterized inflammatory and metabolic phenotypes as well as the gut microbiome associated with ovariectomy and high-fat diet feeding, compared to gonadal intact and low-fat diet controls. We then performed fecal microbiota transplantation (FMT) using gnotobiotic mice to identify the impact of ovariectomy-associated gut microbiome on inflammatory and metabolic outcomes. We demonstrated that ovariectomy led to greater gastrointestinal permeability and inflammation of the gut and metabolic organs, and that a high-fat diet exacerbated these phenotypes. Ovariectomy also led to alteration of the gut microbiome, including greater fecal β-glucuronidase activity. However, differential changes in the gut microbiome only occurred when fed a low-fat diet, not the high-fat diet. Gnotobiotic mice that received the gut microbiome from ovariectomized mice fed the low-fat diet had greater weight gain and hepatic gene expression related to metabolic dysfunction and inflammation than those that received intact sham control-associated microbiome. These results indicate that the gut microbiome responds to alterations in female sex hormone status and contributes to metabolic dysfunction. Identifying and developing gut microbiome-targeted modulators to regulate sex hormones may be useful therapeutically in remediating menopause-related diseases.

Keywords: Gut microbiota; estrogen; menopause; metabolic health; ovarian deficiency.

Figure 1.

Animal characteristics of conventionally raised C57BL/6J mice that underwent either ovariectomy (OVX) or sham (SHM) surgery and fed either a low-fat (LFD) or a high-fat diet (HFD). Final body weight (a) and energy intake (b) at the end of the 12-week study period as well as body weight (c) and energy intake (d) throughout the study time frame are plotted. Total body fat assessed using EchoMRI (e), serum lipopolysaccharide binding protein (LPSBP) concentration (f), liver steatosis (g), and adipocyte cell size (H) were assessed at the end of the study. *denotes main diet effect; +denotes main surgery effect; interactions are denoted either by superscript letters in box plots or by # sign in line graphs, p < .05.

Figure 2.

Gene expression profiles of tissues collected from conventionally-raised C57BL/6J mice that underwent either ovariectomy (OVX) or sham (SHM) surgery and fed either a low-fat (LFD) or a high-fat diet (HFD). Hierarchical clustering based on similarity of gonadal adipose tissue (GDAT) gene expression with (a) and relative expression of genes related to inflammation and tight junction proteins in GDAT, subcutaneous adipose tissue (SQAT), liver, and cecum (b-i) . Each row in the heatmap represents a specific gene of interest, and each column represents one sample with color code denoting treatment groups (SHM-LFD: blue; OVX-LFD: red; SHM-HFD: yellow; OVX-HFD: green). *denotes main diet effect; +denotes main surgery effect; interactions are denoted by superscript letters, p < .05.

Figure 3.

Cecal microbiota and fecal β-glucuronidase activity of ovariectomized (OVX) or sham-operated (SHM) conventionally raised C57BL/6J mice fed either a low-fat (LFD) or a high-fat diet (HFD). Weighted UniFrac principal coordinates analysis (PCoA) plots (a), phylogenetic diversity (b), Firmicutes:Bacteroidetes ratio (c), taxonomic classification at the phylum (d) and family (e) level of cecal microbiota, and the fecal β-glucuronidase activity (f) 12-week post ovariectomy intervention (n=8–10/group). *denotes main diet effect, p < .05.

Figure 4.

Gut microbiota and weight gain of gnotobiotic mice (R) colonized with fecal samples obtained from ovariectomized (OVX) or sham-operated (SHM) donor C57BL/6J mice fed a low-fat diet. Fecal microbiota transplantation (FMT) was performed by transplanting the gut microbiome from conventionally-raised OVX or SHM C57BL/6J (B6) mice fed the LFD into the germ-free (GF) recipients (a). The gut microbiota samples obtained from the HFD-fed donors were not used in the FMT study due the lack of distinct clustering of the gut microbiota based on treatment groups. Weighted UniFrac principal coordinates analysis (PCoA) plots (b), taxonomic classification at the phylum (c) and family (d) level of cecal microbiota, body weight gain (e) and the fecal β-glucuronidase activity (f) 4-week post-colonization at euthanasia (n=11–13/group).

Figure 5.

Gene expression of gnotobiotic recipient mice (R) four weeks after being colonized with microbiota of ovariectomized (OVX) or sham-operated (SHM) donor C57BL/6J mice fed a low-fat diet. Hierarchical clustering based on similarity of the hepatic gene expression (a) and relative expression of genes related to inflammation and tight junction proteins in liver, proximal colon (P. Colon), and cecum (b-i) of gnotobiotic mice. Each row of the heatmap represents a specific gene of interest, and each column represents one sample with color code denoting treatment groups (SHM-R: blue; OVX-R: red). *p < .05, **p < .01, ****p < .0001.