17β-estradiol lowers triglycerides in adipocytes via estrogen receptor α and it may be attenuated by inflammation

Estrogen: the forgotten player in metaflammation

Metaflammation is low-grade inflammation triggered by chronic metabolic imbalance and caused by dysregulated metabolites in metabolic inflammatory syndrome (MIS), which includes four diseases: obesity, type 2 diabetes mellitus (T2DM), atherosclerosis (AS), and nonalcoholic fatty liver diseases (NAFLD, recently proposed to be replaced by metabolic dysfunction-associated steatotic liver disease, MASLD). These diseases exhibit apparent sex dimorphism as regards MIS. Estrogen not only plays a crucial role in gender differences in adults but also possesses an anti-inflammatory effect on many metabolic diseases. In this study, we present a prediction of the differential proteins and signal transduction of estrogen in MIS through network pharmacology and review the validated studies on obesity, T2DM, AS, and NAFLD. Subsequently, we compared them to obtain valuable targets, identify current gaps, and provide perspectives for future research on the mechanisms of estrogen in metaflammation.

Effect of ovariectomy and high-fat diet on the expression of estrogen receptors and adipose tissue metabolism in wistar rats

This study addresses the increasing prevalence of obesity, especially among postmenopausal. Estrogen plays a crucial role in regulating adipose tissue in women, with its absence after menopause associated with metabolic complications. The study aimed to determine the lipolytic activity in different adipose tissue depots of ovariectomized rats submitted to a high-fat diet. Also, to analyze the expression of estrogen receptors in adipose tissues and perform histological and morphometric analyzes of these deposits. Female rats were ovariectomized (O) or sham operated (S). The animals were divided into groups: ovariectomized with high-fat diet (OF), sham-operated with high-fat diet (SF), ovariectomized with control diet (OC) or sham-operated with control diet as the control group (SC). After 24 weeks of consuming the diets, rats were killed and adipose tissue deposits were removed. Polymerase chain reaction was performed to analyze the expression of estrogen receptors in adipose tissues, lipolysis assay and histological analysis. Both the high-fat diet and ovariectomy increased body weight and adiposity. There was hypertrophy of adipocytes. Estrogen replacement therapy modulate lipolytic activity in different adipose depots, with different responses in relation to estrogen receptors. Estrogen receptor expression varied between fat depots. Mesenteric adipose tissue showed greater sensitivity to estrogen compared with others. Estrogen increased lipolytic activity in some fat depots, reducing in others. Expression of ERs depends of hormonal status and adipose tissue location, which may explain distinct actions of estrogen on the metabolism of adipose tissue and on the production of adipokines by them.

Sexual Dimorphism's impact on adipogenesis: A three-dimensional in vitro model treated with 17β-estradiol and testosterone

Using a three-dimensional (3-D) in vitro culture model, we report the dose dependent effect of 17β-estradiol and testosterone on the adipogenic differentiation and maturation of human adipose derived stem cells (hASCs) obtained from female and male patients. Considering sexual dimorphism, we expected male and female adipocytes to respond differently to the sex steroids. Both male and female hASC spheroids were exposed to 100 nM and 500 nM of 17β-estradiol and testosterone either at the beginning of the adipogenic maturation (Phase I) to discourage intracellular triglyceride accumulation or exposed after adipogenic maturation (Phase II) to reduce the intracellular triglyceride accumulation. The results show that 17β-estradiol leads to a dose dependent reduction in intracellular triglyceride accumulation in female hASC spheroids compared to the both untreated and testosterone-treated cells. Affirming our hypothesis, 17β-estradiol prevented intracellular triglyceride accumulation during Phase I, while it stimulated lipolysis during Phase II. PPAR-γ and adiponectin gene expression also reduced upon 17β-estradiol treatment in female cells. Interestingly, 17β-estradiol and testosterone had only a modest effect on the male hASC spheroids. Collectively, our findings suggest that 17β-estradiol can prevent fat accumulation in adipocytes during early and late stages of maturation in females.

The therapeutic potential of irisin to mitigate the risk of metabolic syndrome in postmenopausal women

Oestradiol withdrawal at menopause predisposes women to metabolic syndrome, a cluster of interrelated conditions including obesity, insulin resistance, dyslipidaemia and hypertension that together confer an increased risk of developing type 2 diabetes mellitus and cardiovascular disease. Hormone replacement therapies are commonly used to treat acute symptoms of the perimenopausal period, and whilst they have been associated with metabolic improvements in many studies, long-term use is considered unviable. Novel approaches are required to mitigate the risk of postmenopausal metabolic syndrome. In 2012, the exercise-inducible myokine irisin was isolated from the skeletal muscle of mice and identified to have anti-obesity and antidiabetic effects in vivo. Irisin is now recognised to exert pleiotropic action on cognitive, bone and metabolic health. There is accumulating evidence from in vitro and in vivo rodent studies that irisin can mitigate each component condition of metabolic syndrome. In postmenopausal women, independent associations have been observed between (a) exercise and plasma irisin concentration and (b) plasma irisin concentration and reduced incidence of metabolic syndrome. To date, however, no study has considered the mechanistic basis by which irisin, whether exercise-induced or exogenously administered, could reduce the incidence or severity of metabolic syndrome in postmenopausal women. This review aims to analyse the literature concerning the metabolic actions of irisin, with a focus on its therapeutic potential for metabolic syndrome driven by a state of oestradiol depletion. It evaluates the practicality of exercise as a therapy and discusses other irisin-based therapeutic strategies that may alleviate postmenopausal metabolic syndrome. Finally, it highlights areas where future research is required to advance knowledge of irisin's biological action such that it could be considered a viable candidate for clinical application.

Alpha-lipoic acid supplementation reverses the declining quality of oocytes exposed to cyclophosphamide

Cyclophosphamide (CY) is a chemotherapeutic drug that is commonly used to treat malignancies of the ovary, breast, and hematology, as well as autoimmune disorders. As a cofactor of mitochondrial multienzyme complexes, alpha lipoic acid (ALA) is well known for its antioxidant characteristics, which operate directly on the scavenging of reactive oxygen species (ROS) and indirectly on the intracellular recycling of other antioxidants. However, the underlying mechanisms through which CY exerts its toxic effects on meiosis and oocyte quality, as well as a viable approach for protecting oocyte quality and preserving fertility, remain unknown. In present study, immunostaining and fluorescence intensity quantification were applied to assess the effects of CY and ALA supplementation on the key processes during the oocyte meiotic maturation. Our results show that supplementing oocytes with ALA, a well-known antioxidant and free radical scavenger, can reverse CY-induced oocyte meiotic maturation failure. Specifically, we found that CY exposure caused oocyte meiotic failure by disrupting meiotic organelle dynamics and arrangement, as well as a prominently impaired cytoskeleton assembly. In addition, CY caused an abnormal distribution of mitochondrion and cortical granules, two indicators of oocyte cytoplasmic maturation. More importantly, we show that ALA supplementation effectively reverses CY-induced meiotic failure and oocyte quality decline by suppressing oxidative stress-induced DNA damage and apoptosis in oocytes. Collectively, our data reveal that ALA supplementation is a feasible approach to protect oocytes from CY-exposed deterioration, providing a better understanding of the mechanisms involved in chemotherapy-induced meiotic failure.

Cisplatin-activated ERβ/DCAF8 positive feedback loop induces chemoresistance in non-small cell lung cancer via PTEN/Akt axis

High levels of the estrogen receptor β (ERβ) predict poor prognosis following platinum-containing adjuvant chemotherapies in patients with non-small cell lung cancer (NSCLC). However, the precise role of ERβ remains elusive. In this study, we demonstrated that targeting ERβ could significantly increase the cytotoxicity of cisplatin both in vitro and in vivo. Mechanically, cisplatin directly binds to ERβ, which facilitates its homodimerization and nuclear translocation. ERβ activation transcriptionally represses the expression of DCAF8, an adaptor of CRL4 E3 ubiquitin ligase, which in turn attenuates the proteasomal degradation of ERβ, leading to ERβ accumulation; this positive feedback loop results in Akt activation and eventually cisplatin resistance in NSCLC through PTEN inhibition. Moreover, low expression of DCAF8 and high expression of ERβ are associated with treatment resistance in patients receiving cisplatin-containing adjuvant chemotherapy. The present results provide insights into the underlying mechanism of ERβ-induced cisplatin resistance and offer an alternative therapeutic strategy to improve the efficacy of platinum-based chemotherapy in patients with NSCLC.

Bushen Huoxue formula for the treatment of diminished ovarian reserve: A combined metabolomics and integrated network pharmacology analysis

Objective

This study aimed to explore the mechanism of the Bushen Huoxue Formula (BHF) in treating diminished ovarian reserve (DOR) through the use of metabolomics and integrated network pharmacology.

Methods

The study involved 24 non-pregnant female Sprague-Dawley rats, divided into four groups of six rats each: control, model, BHF, and DHEA (n = 6 per group). The model group was induced with DOR by administering Tripterygium glycosides orally [50 mg (kg·d)-1] for 14 days. Subsequently, BHF and Dehydroepiandrosterone (DHEA) treatments were given to the respective groups. Ovarian reserve function was assessed by measuring anti-Müllerian hormone (AMH), estradiol (E2), and follicle-stimulating hormone (FSH) levels and conducting hematoxylin-eosin staining. In addition, UHPLC-QTOF-MS analysis was performed to identify differential metabolites and pathways in DOR rats treated with BHF. In this study, LC-MS was utilized to identify the active ingredients of BHF, while network pharmacology was employed to investigate the correlations between BHF-related genes and DOR-related genes. An integrated analysis of metabonomics and network pharmacology was conducted to elucidate the mechanisms underlying the efficacy of BHF in treating DOR.

Results

The model group exhibited a poor general condition and a significant decrease in the number of primordial, primary, and secondary follicles (P < 0.05) when compared to the control group. However, BHF intervention resulted in an increase in the number of primordial, primary, and secondary follicles (P < 0.05), along with elevated levels of AMH and E2 (P < 0.05), and a decrease in FSH levels (P < 0.05) in DOR rats. The modeling process identified eleven classes of metabolites, including cholesterol esters (CE), diacylglycerols (DAG), hexosylceramides (HCER), lysophosphatidylcholines (LPC), phosphatidylcholines (PC), phosphatidylethanolamines (PE), sphingomyelins (SM), ceramides (CER), free fatty acids (FFA), triacylglycerols (TAG), and lysophosphatidylethanolamines (LPE). The study found that PC, CE, DAG, and TAG are important metabolites in the treatment of DOR with BHF. LC-MS analysis showed that there were 183 active ingredients in ESI(+) mode and 51 in ESI(-) mode. Network pharmacology analysis identified 285 potential genes associated with BHF treatment for DOR in ESI(+) mode and 177 in ESI(-) mode. The combined analysis indicated that linoleic acid metabolism is the primary pathway in treating DOR with BHF.

Conclusion

BHF was found to improve ovarian function in rats with DOR induced by Tripterygium glycosides. The study identified key metabolites such as phosphatidylcholine (PC), cholesteryl ester (CE), diacylglycerol (DAG), triacylglycerol (TAG), and the linoleic acid metabolism pathway, which were crucial in improving ovarian function in DOR rats treated with BHF.

Apolipoprotein C3 is negatively associated with estrogen and mediates the protective effect of estrogen on hypertriglyceridemia in obese adults

BACKGROUND

Both estrogen and apolipoprotein C3 (ApoC3) play crucial roles in lipid metabolism. But the link between them remains unclear, and it is unknown whether estrogen regulates triglyceride (TG) levels via ApoC3. Researchers hypothesized that estrogen exerts a regulatory effect on ApoC3 metabolism, and that this regulation could play a significant role in lipid metabolism. To explore this potential link, the present investigation aimed to examine the associations between estradiol (E2), ApoC3, and TG levels in both males and females.

METHODS

A total of 519 obese people (133 males and 386 premenopausal females) were recruited. Based on their TG levels, the participants were split into two groups [hypertriglyceridemia (HTG) group: TG ≥ 1.7 mmol/L; control group: TG < 1.7 mmol/L]. Serum ApoC3, E2, and TG levels were measured and compared in those two groups for both sexes separately. To ascertain the connection among E2, ApoC3, and TG, linear regression and mediation analysis were used.

RESULTS

Participants in the HTG group presented higher levels of ApoC3 (P < 0.001). In contrast, they tend to have lower E2 levels than the control. Linear regression analysis proposed that in both sexes, E2 was negatively associated with ApoC3 levels. The relationship remained significant after adjustment for confounding factors (male: standardized β = -0.144, t = -2.392, P < 0.05; female: standardized β = -0.077, t = -2.360, P < 0.001). Furthermore, mediation analysis revealed the relationship between reduced E2 levels and elevated TG levels is directly mediated by ApoC3.

CONCLUSIONS

In obese men and premenopausal women, ApoC3 was negatively and linearly correlated with serum E2 levels. The findings showed that estrogen may suppress ApoC3 expression and thus lower TG levels.

Downregulation of peripheral lipopolysaccharide binding protein impacts on perigonadal adipose tissue only in female mice

BACKGROUND AND AIMS

The sexual dimorphism in fat-mass distribution and circulating leptin and insulin levels is well known, influencing the progression of obesity-associated metabolic disease. Here, we aimed to investigate the possible role of lipopolysaccharide-binding protein (LBP) in this sexual dimorphism.

METHODS

The relationship between plasma LBP and fat mass was evaluated in 145 subjects. The effects of Lbp downregulation, using lipid encapsulated unlocked nucleomonomer agent containing chemically modified-siRNA delivery system, were evaluated in mice.

RESULTS

Plasma LBP levels were associated with fat mass and leptin levels in women with obesity, but not in men with obesity. In mice, plasma LBP downregulation led to reduced weight, fat mass and leptin gain after a high-fat and high-sucrose diet (HFHS) in females, in parallel to increased expression of adipogenic and thermogenic genes in visceral adipose tissue. This was not observed in males. Plasma LBP downregulation avoided the increase in serum LPS levels in HFHS-fed male and female mice. Serum LPS levels were positively correlated with body weight and fat mass gain, and negatively with markers of adipose tissue function only in female mice. The sexually dimorphic effects were replicated in mice with established obesity. Of note, LBP downregulation led to recovery of estrogen receptor alpha (Esr1) mRNA levels in females but not in males.

CONCLUSION

LBP seems to exert a negative feedback on ERα-mediated estrogen action, impacting on genes involved in thermogenesis. The known decreased estrogen action and negative effects of metabolic endotoxemia may be targeted through LBP downregulation.

Ovariectomy Causes Degeneration of Perivascular Adipose Tissue

Women are more resistant than men to the development of vascular diseases. However, menopause is a factor leading to deterioration of female vascular integrity, and it is reported that the risk of vascular diseases such as atherosclerosis and abdominal aortic aneurysm is increased in postmenopausal women. Although it is suggested that perivascular adipose tissue (PVAT) is deeply involved in the increased risk of vascular disease development, the effect of menopause on PVAT integrity is unknown. In this study, we aimed to elucidate the effect of menopause on PVAT in ovariectomized (OVX) rats. PVAT was divided into 4 regions based on characteristics. Hypertrophy and increased inflammation of adipocytes in the PVAT were observed in the OVX group, but the effects of OVX were different for each region. OVX induced matrix metalloproteinase (MMP) -9 which degrade extracellular matrix such as elastin and collagen fibers in PVAT. Degeneration of the arterial fibers of the thoracic and abdominal aorta were observed in the OVX group. These results indicate that OVX can cause dysfunction of PVAT which can cause degradation of arterial fibers. Appropriate management of PVAT may play an important role in the prevention and treatment of diseases originating from ovarian hypofunction.

Associations among gonadal hormone, triglycerides and cognitive decline in female patients with major depressive disorders

BACKGROUND

Cognitive impairment has been identified as a core feature of depression. Serum triglycerides (TG), gonadal hormone and sex difference were shown to influence cognitive performance. The purpose of this study was to investigate the associations among serum TG, gonadal hormone, sex difference and cognitive performance in patients with major depressive disorders (MDD).

METHODS

The enrolled 183 patients (male/female = 80/103) meeting DSM-IV criteria for MDD were divided into high TG group (patients-HTG) and normal TG group (patients-NTG) according to TG level. Serum TG, estradiol (E2) and testosterone (T) levels were measured by the glycerokinase peroxidase-peroxidase and chemiluminescence methods. Cognition was assessed by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The study was conducted between August 2016 and January 2020.

RESULTS

In female, patients-HTG had lower immediate memory, language, attention, delayed memory and RBANS total scores than patients-NTG after adjusting for covariates. There were significant differences in serum E2 and T levels between patients-HTG and patients-NTG in female after controlling for covariates. In female patients-HTG, serum E2 level was positively associated with immediate memory, delayed memory and RBANS total scores, and serum T level was positively related to immediate memory, language and RBANS total scores. These findings were not seen in male patients.

CONCLUSIONS

Our data suggested that patients-HTG exhibited poorer cognitive function compared with patients-NTG in female. Moreover, the decline in serum gonadal hormone level might contribute to the high TG development of female MDD, and was further implicated in their cognitive decline.

Diosmetin Protects Against Obesity and Metabolic Dysfunctions Through Activation of Adipose Estrogen Receptors in Mice

SCOPE

Obesity is a major public health and economic problem of global significance. Here, we investigate the role of diosmetin, a natural flavonoid presents mainly in citrus fruits, in the regulation of obesity and metabolic dysfunctions in mice.

METHODS AND RESULTS

Eight-week-old male C57BL/6 mice fed a high-fat diet (HFD) or 5-week-old male ob/ob mice fed a normal diet are treated with diosmetin (50 mg kg^-1 daily) or vehicle for 8 weeks. Diosmetin treatment decreases body weight and fat mass, improves glucose tolerance and insulin resistance in obese mice. These metabolic benefits are mainly attributed to increase energy expenditure via enhancing thermogenesis in brown adipose tissue (BAT) and browning of white adipose tissue (WAT). Mechanistically, diosmetin acts as an agonist for estrogen receptors (ERs), and subsequently elevates adipose expressions of ERs in mice and in cultured adipocytes. When ERs are blocked by their antagonist fulvestrant in mice, diosmetin loses its beneficial effects, suggesting that ERs are indispensable for the metabolic benefits of diosmetin.

CONCLUSION

The results indicate that diosmetin may be a potential anti-obesity nutritional supplement and could be explored for low ERs-related obesity populations.

Lower Baseline Serum Triglyceride Levels Are Associated With Higher Decrease in Body Mass Index After Laparoscopy Sleeve Gastrectomy Among Obese Patients

AIMS

To investigate the predictive value of baseline serum triglyceride (TG) levels for improvements of metabolism after laparoscopic sleeve gastrectomy (LSG).

METHODS

112 obese patients [body mass index (BMI) ≥ 35 kg/m²] underwent LSG and with complete information of anthropometric and metabolic parameters were divided into normal TG group (group A) and high TG group (group B), while group A had TG levels ≤ 1.7 mmol/L, and group B had TG levels > 1.7 mmol/L. The post-operative changes (Δ) in metabolic parameters between the two groups were compared.

RESULTS

In the whole cohort, the metabolic parameters were significantly improved at 6 months after LSG. BMI and waist circumference (WC) decreased significantly in the two groups. The ΔBMI among group A and group B were 11.42±3.23 vs 9.13±2.77 kg/m² (p<0.001), respectively. ΔBMI was positively correlated with ΔWC (r=0.696, p<0.001), Δfasting insulin level (r=0.440, p=0.002), Δfasting serum C peptide level (r=0.453, p=0.002), and Δhomeostasis model assessment insulin resistance index (r=0.418, p=0.004) in group A. Compared with group B, group A had a significantly higher odds ratio (OR) of 2.83 (95% confidence interval [CI]1.25-6.38, p=0.012)and 2.73 (95% CI 1.11-6.72, p=0.029) for ΔBMI and ΔWC after adjustment for age and gender, respectively.

CONCLUSIONS

Obese patients with baseline TG levels under 1.7 mmol/L had greater loss of weight at six months follow-up later LSG. This finding suggests that baseline TG level may have a predictive value for weight loss, at least in the short-term follow-up.

Sex Differences in Adipose Tissue Function

Regional adipose tissue distribution differs between men and women. Differences in the accumulation of adipose tissue as well as the regulation of secretion of a number of products from adipose tissue are under the control of sex steroids, which act through a wide variety of mechanisms, both direct and indirect, to tailor metabolism to the unique needs of each sex. A fuller understanding of sex-based differences in adipose tissue function may help with tailored strategies for disease prevention and treatment and provide insights into fundamental differences in the processes that regulate nutrient homeostasis and body weight.

Endometriosis Pathoetiology and Pathophysiology: Roles of Vitamin A, Estrogen, Immunity, Adipocytes, Gut Microbiome and Melatonergic Pathway on Mitochondria Regulation

Endometriosis is a common, often painful, condition that has significant implications for a woman’s fertility. Classically, endometriosis has been conceptualized as a local estrogen-mediated uterine condition driven by retrograde menstruation. However, recent work suggests that endometriosis may be a systemic condition modulated, if not driven, by prenatal processes. Although a diverse array of factors have been associated with endometriosis pathophysiology, recent data indicate that the low body mass index and decreased adipogenesis may be indicative of an early developmental etiology with alterations in metabolic function crucial to endometriosis pathoetiology.

The present article reviews the data on the pathoetiology and pathophysiology of endometriosis, suggesting key roles for alterations in mitochondria functioning across a number of cell types and body systems, including the immune system and gut microbiome. These changes are importantly regulated by decreases in vitamin A and its retinoic acid metabolites as well as increases in mitochondria estrogen receptor-beta and the N-acetylserotonin/melatonin ratio across development. This has treatment and future research implications for this still poorly managed condition, as well as for the association of endometriosis with a number of cancers.

17β-Estradiol protects the esophageal epithelium from IL-13-induced barrier dysfunction and remodeling

BACKGROUND

The incidence of eosinophilic esophagitis (EoE) is greater in male than female subjects, and the underlying molecular basis for this sex bias remains unclear.

OBJECTIVE

We sought to delineate the contribution of the sex hormone estrogen to the EoE phenotype and esophageal epithelial barrier function and remodeling.

METHODS

We performed demographic and incidence analyses of EoE in male and female subjects from a single-center pediatric cohort. Estrogen-responsive gene expression analyses and estrogen receptor (ESR) immunofluorescence staining of esophageal biopsy specimens from patients with EoE and control subjects were performed. The effect of 17β-estradiol (E2) on IL-13-induced signaling pathways, gene expression, and esophageal epithelial architecture and barrier function in a primary human esophageal keratinocyte cell (EPC2) culture system (EPC2-air-liquid interface) was examined.

RESULTS

We observed a male predominance in patients with EoE. Analyses of RNA sequencing data sets revealed a significant dysregulation of the estrogen-responsive gene network and expression of ESR1 and ESR2 in esophageal biopsy specimens from patients with EoE compared with control subjects. IL-13 stimulation of EPC2-air-liquid interface cells led to altered cellular architecture with induced dilation of intercellular spaces and barrier dysfunction. Pretreatment of EPC2s with E2 prior to IL-13 exposure abrogated IL-13-induced architectural changes and esophageal barrier dysfunction. Mechanistically, E2-protective effects were dependent on ESR2 and associated with diminishing of IL-13-induced tyrosine kinase 2 and signal transducer and activator of transcription 6 phosphorylation and EoE-dysregulated gene expression.

CONCLUSIONS

Estrogen-responsive genes are modified in patients with EoE compared with control subjects. E2 attenuated IL-13-induced architectural changes and esophageal epithelial barrier dysfunction through inhibition of the IL-13/tyrosine kinase 2/signal transducer and activator of transcription 6 pathway via ESR2-dependent process. Estrogen hormone signaling may protect against development of EoE in female subjects.

Effects of Diethyl Phosphate, a Non-Specific Metabolite of Organophosphorus Pesticides, on Serum Lipid, Hormones, Inflammation, and Gut Microbiota

Organophosphorus pesticides (OPs) can be metabolized to diethyl phosphate (DEP) in the gut environment, which may affect the immune and endocrine systems and the microbiota. Correlations between OPs and diseases have been established by epidemiological studies, mainly based on the contents of their metabolites, including DEP, in the serum or urine. However, the effects of DEP require further study. Therefore, in this study, adult male rats were exposed to 0.08 or 0.13 mg/kg DEP for 20 weeks. Serum levels of hormones, lipids, and inflammatory cytokines as well as gut microbiota were measured. DEP significantly enriched opportunistic pathogens, including Paraprevotella, Parabacteroides, Alloprevotella, and Helicobacter, leading to a decrease in interleukin-6 (IL-6). Exposure to the high dose of DEP enriched the butyrate-producing genera, Alloprevotella and Intestinimonas, leading to an increase in estradiol and a resulting decrease in total triglycerides (TGs) and low-density lipoprotein cholesterol (LDL-C); meanwhile, DEP-induced increases in peptide tyrosine‒tyrosine (PYY) and ghrelin were attributed to the enrichment of short-chain fatty acid-producing Clostridium sensu stricto 1 and Lactobacillus. These findings indicate that measuring the effects of DEP is not a proxy for measuring the effects of its parent compounds.

Estradiol signaling mediates gender difference in visceral adiposity via autophagy

Excessive adiposity (particularly visceral fat mass) increases the risks of developing metabolic syndrome. Women have lower deposit of visceral fat than men, and this pattern becomes diminished postmenopausally, but the underlying mechanism remains largely unknown. Here, we show that the gender difference in visceral fat distribution is controlled by an estradiol-autophagy axis. In C57BL/6J and wild-type control mice, a higher visceral fat mass was detected in the males than in the females, which was associated with lower expression of estrogen receptor α (ERα) and more active autophagy in males vs. females. However, deletion of ERα normalized autophagy activity and abolished the gender difference in visceral adiposity. In line with the adiposity-reducing effect of the ERα-autophagy axis, we found that downregulation of ERα and increased autophagy activity were required for adipogenesis, while induction of estradiol signaling dampened autophagy and drastically prevented adipogenesis. Mechanistically, the estradiol-ERα signaling activated mTOR, which phosphorylated and inhibited ULK1, thereby suppressing autophagy and adipogenesis. Together, our study suggests that the lower visceral adiposity in the females (vs. the males) arises from a more active estradiol-ERα signaling, which tunes down autophagy and adipogenesis.