Project description:In general, women are more susceptible to xerostomia than men. Clinical studies have indicated a noteworthy increase in the incidence of xerostomia following menopause, along with a negative correlation between saliva estrogen levels and the severity of xerostomia symptoms. Similarly, ovariectomy (OVX) in rodents not only decreases saliva secretion but also triggers pathological alterations in the SG. We used microarrays to detail the global programme of gene expression underlying OVX-mediated SG dysfuction.
Project description:White adipose tissue (WAT) distribution is sex dependent. Adipocyte hyperplasia contributes to WAT distribution in mice driven by cues in the tissue microenvironment, with females displaying hyperplasia in subcutaneous and visceral WAT, while males and ovariectomized females have visceral WAT (VWAT)-specific hyperplasia. However, the mechanism underlying sex-specific hyperplasia remains elusive. Here, transcriptome analysis in female mice shows that high-fat diet (HFD) induces estrogen signaling in adipocyte precursor cells (APCs). Analysis of APCs throughout the estrous cycle demonstrates increased proliferation only when proestrus (high estrogen) coincides with the onset of HFD feeding. We further show that estrogen receptor α (ERα) is required for this proliferation and that estradiol treatment at the onset of HFD feeding is sufficient to drive it. This estrous influence on APC proliferation leads to increased obesity driven by adipocyte hyperplasia. These data indicate that estrogen drives ERα-dependent obesogenic adipocyte hyperplasia in females, exacerbating obesity and contributing to the differential fat distribution between the sexes.
Project description:Epidemiological studies highlight a strong association between obesity and colorectal cancer (CRC). This association appears stronger in men and a role for sex hormones is indicated by epidemiological studies. Especially estrogen is protective against CRC and correlated to several aspects of the metabolic syndrome. Anti-inflammatory and anti-tumorigenic effects of estrogen in colon have been demonstrated to act via estrogen receptor beta (ERβ). This led us to hypothesize that estrogenic signaling, through both systemic and local effects might modulate the colon microenvironment during HFD-induced obesity. In order to test our hypothesis mice were fed a control diet or a high fat diet (HFD) for 3 weeks and treated with different estrogenic ligands. In the present study, we demonstrate that there are sex-differences in the response to HFD-induced obesity and in the colon transcriptome. Both sexes develop obesity with an impaired circadian rhythm but the male metabolic profile is more sensitive to HFD and increased the colon epithelial cell proliferation. Females were resistant to impaired glucose metabolism, but HFD-feeding increased the infiltration of macrophages. Estrogen signaling in males, via ERα, presented anti-obesogenic effects. However, systemic and/or local activation of both ERα and ERβ restored the circadian rhythm in the males. In females, systemic activation of ERα restored the circadian rhythm, however, systemic and/or local activation of ERβ down-regulated the expression of macrophage markers. These results suggest that estrogen signaling through systemic and/or local activation of ERβ can regulate the colon microenvironment during HFD-induced obesity.
Project description:Obesity during menopause contributes risk for mood disorders, dementia and Alzheimer’s disease (AD). Given the high prevalence of obesity among postmenopausal women there is an urgent need to evaluate the efficacy of hormone therapy (HT) administered immediately (vs delayed) at menopause in different brain regions involved in memory and cognition. Here, and to more closely replicate the endocrine environment of obese postmenopausal women, either on or off HT, middle-aged female rhesus macaques were ovariectomized/hysterectomized (OvH) and maintained on a high-fat, high-sugar, obesogenic Western-style diet (WSD) for 30 months; half of the animals received HT immediately after OvH and half served as placebo controls. RNAseq of the occipital (OC) and prefrontal cortex (PFC), hippocampus (HIP) and amygdala (AMG), identified 293, 379, 505 and 4,993 differentially expressed genes (DEGs), respectively. Pathway enrichment analysis, identified an activation of neuroinflammation in OC and HIP, but an inhibition in the AMG with HT. Synaptogenesis, circadian rhythm, mitochondrial dysfunction, mTOR, glutamate, serotonin, GABA, dopamine, noradrenaline/adrenaline, glucocorticoid receptor signaling. neuronal NOS and amyloid processing were exclusively enriched in AMG. As compared to the placebo control group, most of these signaling pathways are downregulated after HT, suggesting a protective effect of HT in OvH females under a WSD. Overall, our results suggest that a chronic obesogenic diet may induce a wide range of alterations in multiple signaling pathways that are linked to age-associated brain pathology and dementia. In these individuals, HT seems to have a protective effect against neuroinflammation, amyloid beta depositions and tau tangles formation.
Project description:More women than men have died from heart disease over the last 20-25 years, with morbidity and mortality rising in women after menopause supported to be result of decreased circulating estrogen. Current literature lacks an understanding of the cellular and molecular mechanisms that capture the shift in susceptibility to cardiovascular disease (CVD) during the menopausal transition from pre- to peri- to menopause. Therefore, through use of a chemical model (4-vinylcyclohexene diepoxide; VCD) of ovarian failure, which allows us to preserve the peri-menopause state, we performed transcriptomic and proteomic analysis on post-mortem heart tissue. In general, pre-, peri-, and menopausal hearts clustered more closely (most similar) within each experimental group and perimenopausal hearts clustered more closely with premenopausal hearts than menopausal hearts (least similar). Both proteomes and transcriptomes showed similar trends in genes associated with atherothrombosis, contractility, and impaired nuclear signaling between pre-, peri-, and menopausal hearts. From this, we emphasized a menopause and angiotensin II (AngII) effect on AMP-activated protein kinase (AMPK) signaling and histone deacetylase (HDAC) activity where we found both an estrogen- and pathologic-dependent increase in phosphorylation of AMPK and decrease in class I HDAC activity. Additionally, we found a menopause-dependent decrease in class IIa HDAC activity and increase in class IIb activity. These findings suggest unique changes in pre-, peri-, and menopausal mice indicative of metabolic reprogramming and adverse cardiac remodeling with loss of estrogen.
Project description:In women, estrogen deficiency after menopause frequently accelerates osteoclastic bone resorption, leading to osteoporosis, the most common skeletal disorder. However, mechanisms underlying osteoporosis resulting from estrogen deficiency remain largely unknown. To gain new insights into the impact of estrogen on bone marrow B cells, we used high-throughput sequencing to analyze global estrogen transcriptional networks in WT bone marrow B cells under hypoxic culture.
Project description:Menopause - when estrogen (E2) levels are decreased - is associated with a loss of skeletal muscle mass and strength. We performed genome-wide expression profiling to identify the underlying mechanisms.
Project description:Ageing compromises the mechanical properties of skin, with increased fragility and coincident slowing of the healing process making aged skin susceptible to chronic wounding. The ageing process is driven by an aggregation of damage to cells and extracellular matrix, compounded by regulatory changes, including age-associated hormonal dysregulation. Here we report on the correlation between mechanical properties and composition of skin from ovariectomised and chronologically aged mice, to assess the extent to which estrogen deprivation drives dermal ageing. We found that age and estrogen abrogation affected skin mechanical properties in contrasting ways: ageing lead to increased tensile strength and stiffness while estrogen deprivation had the opposite effect. Mass spectrometry proteomics showed that the quantity of extractable fibrillar collagen-I decreased with ageing, but no change was observed in ovariectomised mice. This observation, in combination with measurements of tensile strength, was interpreted to reflect changes to the extent of extracellular matrix crosslinking, supported by a significant increase in the staining of advanced glycation endpoints in aged skin. Loss of mechanical strength in the ovariectomy model was consistent with a loss of elastic fibres. Other changes in extracellular matrix composition broadly correlated between aged and ovariectomised mice, indicative of the role of estrogen-related pathways in ageing. This study offers a coherent picture of the relationship between tissue composition and mechanics, but suggests that the deleterious effects of intrinsic skin ageing are compounded by factors beyond hormonal dysregulation.
Project description:The ongoing pandemics of obesity and hypertension have increasingly impacted an aging population with heart disease creating a prevalent cardiometabolic syndrome (CMS). This affects many post-menopausal women and men and manifests by multi-organ adiposity, insulin desensitization and diabetes, impaired fat metabolism, and heart failure symptoms. Effective therapy countering these multiple defects remains lacking. Natriuretic peptides (NP) synthesized by the heart both protect against cardiac disease and reduce obesity by stimulating lipolysis, improving insulin signaling, and lowering appetite. However, their clinical translation remains stymied by blood pressure reduction and complex in vivo peptide pharmacology. Phosphodiesterase type 9 is expressed in myocardium and fat of mammals including humans and controls NP-coupled cyclic GMP hydrolysis. Its inhibition (PDE9-I) protects hearts against pressure-induced stress without changing blood pressure, though its impact on fat remains unknown. Here we show PDE9-I potently improves high-fat diet-induced severe obesity in mice with cardiometabolic syndrome without altering food intake or activity, but this only occurs in males and ovariectomized females. PDE9 localizes with mitochondria and its inhibition stimulates mitochondrial respiration, uncoupling, and fat oxidation in heart and adipose tissue to reduce abdominal and liver fat by activating peroxisome proliferator-activator receptor a (PPARa) signaling. ChIP-seq reveals that the sexual dimorphism relates to reduced PPARa DNA binding in genes regulating fatty acid metabolism due to estrogen-receptor activation. Human translation is revealed in obese patients with heart failure and preserved ejection fraction (HFpEF), in whom PDE9A and PPARA gene expression inversely correlate, and PPARA and fat metabolism regulated genes are reduced. This potent PDE9-PPARa regulated pathway has implications for treating obese post-menopausal females and males with cardiometabolic syndrome. HFpEF accounts for half of all heart failure and is now commonly associated with class II (BMI>35 kg/m2) or greater obesity and CMS. The obesity is particularly hard to treat in these patients given that exercise capacity is quite limited, diet is rarely impactful at such weight, and surgical therapy poses greater risks. Despite having heart disease, NP levels are often low as hearts are less dilated and there is greater peripheral clearance with obesity. Loss of estrogen after menopause increases female risks for cardiovascular disease and stimulates visceral adiposity. Ovariectomy (OVX) mimics these changes, and when combined with a high-fat diet, exacerbates adiposity and adverse consequences of ischemic and hypertensive stress. These are reversed by exogenous estrogen but not therapies that require intact nitric oxide signaling, revealing an important role of estrogen-NO pathways. Estrogen treatment is largely abandoned due to adverse effects in humans. However, PDE9-I elevates cGMP-signaling by the NP pathway independent of NO-stimulation. We hypothesized that PDE9-I retains cardiac benefits in OVX female hearts subjected to pressure-induced stress and may also stimulate fat loss to improve CMS in concomitant diet induced obesity.