Beta 3 Adrenergic Receptor Activation Rescues Metabolic Dysfunction in Female Estrogen Receptor Alpha-Null Mice

Metabolic disease risk escalates following menopause. The mechanism is not fully known, but likely involves reduced signaling through estrogen receptor alpha (ERα), which is highly expressed in brown and white adipose tissue (BAT and WAT).Objective: Test the hypothesis that uncoupling protein (UCP1) activation mitigates metabolic dysfunction caused by loss of signaling through ERα.Methods: At 8 weeks of age, female ERα knock out (KO) and wild-type mice were housed at 28°C and fed a Western-style high-fat, high sucrose diet (HFD) or a normal low-fat chow diet (NC) for 10 weeks. During the final 2 weeks, they received daily injections of CL 316,256 (CL), a selective β3 adrenergic agonist, or vehicle control (CTRL), creating eight groups: WT-CTRL, WT-CL, KO-CTRL, and KO-CL on HFD or NC; n = 4–10/group.Results: ERαKO demonstrated exacerbated HFD-induced adiposity gain (P < 0.001) and insulin resistance (P = 0.006). CL treatment improved insulin sensitivity (P < 0.05) and normalized ERαKO-induced adiposity increase (P < 0.05). In both genotypes, CL increased resting energy expenditure (P < 0.05) and induced WAT beiging indicated by increased UCP1 protein in both perigonadal (PGAT) and subcutaneous (SQAT) depots. These effects were attenuated under HFD conditions (P < 0.05). In KO, CL reduced HFD energy consumption compared to CTRL (P < 0.05). Remarkably, CL increased WAT ERβ protein levels of both WT and KO (P < 0.001), revealing CL-mediated changes in estrogen signaling may have protective metabolic effects.Conclusion: CL completely restored metabolic dysfunction in ERαKO mice. Thus, UCP1 may be a therapeutic target for treating metabolic dysfunction following loss of estrogen receptor signaling

Physical Activity Differentially Affects the Cecal Microbiota of Ovariectomized Female Rats Selectively Bred for High and Low Aerobic Capacity.

The gut microbiota is considered a relevant factor in obesity and associated metabolic diseases, for which postmenopausal women are particularly at risk. Increasing physical activity has been recognized as an efficacious approach to prevent or treat obesity, yet the impact of physical activity on the microbiota remains under-investigated. We examined the impacts of voluntary exercise on host metabolism and gut microbiota in ovariectomized (OVX) high capacity (HCR) and low capacity running (LCR) rats. HCR and LCR rats (age = 27 wk) were OVX and fed a high-fat diet (45% kcal fat) ad libitum and housed in cages equipped with (exercise, EX) or without (sedentary, SED) running wheels for 11 wk (n = 7-8/group). We hypothesized that increased physical activity would hinder weight gain, increase metabolic health and shift the microbiota of LCR rats, resulting in populations more similar to that of HCR rats. Animals were compared for characteristic metabolic parameters including body composition, lipid profile and energy expenditure; whereas cecal digesta were collected for DNA extraction. 16S rRNA gene-based amplicon Illumina MiSeq sequencing was performed, followed by analysis using QIIME 1.8.0 to assess cecal microbiota. Voluntary exercise decreased body and fat mass, and normalized fasting NEFA concentrations of LCR rats, despite only running one-third the distance of HCR rats. Exercise, however, increased food intake, weight gain and fat mass of HCR rats. Exercise clustered the gut microbial community of LCR rats, which separated them from the other groups. Assessments of specific taxa revealed significant (p<0.05) line by exercise interactions including shifts in the abundances of Firmicutes, Proteobacteria, and Cyanobacteria. Relative abundance of Christensenellaceae family was higher (p = 0.026) in HCR than LCR rats, and positively correlated (p<0.05) with food intake, body weight and running distance. These findings demonstrate that exercise differentially impacts host metabolism and gut microbial communities of female HCR and LCR rats without ovarian function

Retention of sedentary obese visceral white adipose tissue phenotype with intermittent physical activity despite reduced adiposity

Regular physical activity is effective in reducing visceral white adipose tissue (AT) inflammation and oxidative stress, and these changes are commonly associated with reduced adiposity. However, the impact of multiple periods of physical activity, intercalated by periods of inactivity, i.e., intermittent physical activity, on markers of AT inflammation and oxidative stress is unknown. In the present study, 5-wk-old male C57BL/6 mice were randomized into three groups (n = 10/group): sedentary, regular physical activity, and intermittent physical activity, for 24 wk. All animals were singly housed and fed a diet containing 45% kcal from fat. Regularly active mice had access to voluntary running wheels throughout the study period, whereas intermittently active mice had access to running wheels for 3-wk intervals (i.e., 3 wk on/3 wk off) throughout the study. At death, regular and intermittent physical activity was associated with similar reductions in visceral AT mass (approximately −24%, P < 0.05) relative to sedentary. However, regularly, but not intermittently, active mice exhibited decreased expression of visceral AT genes related to inflammation (e.g., monocyte chemoattractant protein 1), immune cell infiltration (e.g., CD68, CD11c, F4/80, CD11b/CD18), oxidative stress (e.g., p47 phagocyte oxidase), and endoplasmic reticulum stress (e.g., CCAAT enhancer-binding protein homologous protein; all P < 0.05). Furthermore, regular, but not intermittent, physical activity was associated with a trend toward improvement in glucose tolerance (P = 0.059). Collectively, these findings suggest that intermittent physical activity over a prolonged period of time may lead to a reduction in adiposity but with retention of a sedentary obese white AT and metabolic phenotype

White Adipose Tissue Depots Respond to Chronic Beta-3 Adrenergic Receptor Activation in a Sexually Dimorphic and Depot Divergent Manner

Beta-3 adrenergic receptor activation via exercise or CL316,243 (CL) induces white adipose tissue (WAT) browning, improves glucose tolerance, and reduces visceral adiposity. Our aim was to determine if sex or adipose tissue depot differences exist in response to CL. Daily CL injections were administered to diet-induced obese male and female mice for two weeks, creating four groups: male control, male CL, female control, and female CL. These groups were compared to determine the main and interaction effects of sex (S), CL treatment (T), and WAT depot (D). Glucose tolerance, body composition, and energy intake and expenditure were assessed, along with perigonadal (PGAT) and subcutaneous (SQAT) WAT gene and protein expression. CL consistently improved glucose tolerance and body composition. Female PGAT had greater protein expression of the mitochondrial uncoupling protein 1 (UCP1), while SQAT (S, p &lt; 0.001) was more responsive to CL in increasing UCP1 (S&times;T, p = 0.011) and the mitochondrial biogenesis induction protein, PPAR&gamma; coactivator 1&alpha; (PGC1&alpha;) (S&times;T, p = 0.026). Females also displayed greater mitochondrial OXPHOS (S, p &lt; 0.05) and adiponectin protein content (S, p &lt; 0.05). On the other hand, male SQAT was more responsive to CL in increasing protein levels of PGC1&alpha; (S&times;T, p = 0.046) and adiponectin (S, p &lt; 0.05). In both depots and in both sexes, CL significantly increased estrogen receptor beta (ER&beta;) and glucose-related protein 75 (GRP75) protein content (T, p &lt; 0.05). Thus, CL improves systemic and adipose tissue-specific metabolism in both sexes; however, sex differences exist in the WAT-specific effects of CL. Furthermore, across sexes and depots, CL affects estrogen signaling by upregulating ER&beta;

Relative Microbial Abundance and Food Intakes Correlation.

<p>Correlations between the relative abundance of the bacterial communities (OTU) and food intake at wk11 of dietary and exercise interventions. Pearson correlation coefficients (r) are shown for each taxon: (A) Christensenellaceae, (B) Porphyromonadaceae, (C) Clostridiaceae, (D) Peptococcaceae, and (E) Desulfovibrionaceae, with the associated <i>p</i> values.</p

Bacterial phyla, families, and genera of cecal digesta in rats after 11 wk of diet and voluntary wheel running interventions¹.

<p>¹n = 7-8/group, values are means ± SEM.</p><p>²HCR = high capacity runner rats; LCR = low capacity runner rats; EX = voluntary exercise; SED = sedentary.</p><p>³Unknown family within order <i>Clostridiales</i>.</p><p>⁴Unknown family within order <i>Bacteroidales</i>.</p><p>⁵Unknown family within order <i>RF39</i>.</p><p>⁶Unknown family within order <i>YS2</i>.</p><p>Bacterial phyla, families, and genera of cecal digesta in rats after 11 wk of diet and voluntary wheel running interventions<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0136150#t003fn001" target="_blank">¹</a>.</p

Body weight, food intake and daily wheel running distance¹.

<p>¹n = 7-8/group, values are means ± SEM.</p><p>²Body weight, food intake and running distance were measured weekly. Feed efficiency was calculated by dividing amount of energy consumed by each animal by the BW gain. These data represent the mean throughout the 11-wk period.</p><p>³BW = body weight; HCR = high capacity runner rats; LCR = low capacity runner rats; EX = voluntary exercise; SED = sedentary.</p><p>⁴Energy expenditure was measured using indirect calorimetry over a 3-d period at 36 wk of age.</p><p>Body weight, food intake and daily wheel running distance<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0136150#t001fn001" target="_blank">¹</a>.</p

PCoA Plots of Unweighted and Weighted UniFrac Distances.

<p>Unweighted <b>(A)</b> and weighted <b>(B)</b> PCoA was performed based on the UniFrac distance matrix generated from sequencing cecal 16S rRNA genes in samples from HCR and LCR rats. Each dot represents a sample from HCR-EX (big red dots), HCR-SED (small red dots), LCR-EX (big blue dots), and LCR-SED (small blue dots) rats.</p