Project description:Ultraviolet (UV) light affects endocrinological and behavioral aspects of human sexuality via an unknown mechanism. Using a unique male-female comparative approach, we discovered that the sexual behavioral and hormonal features enhanced by UVB are mediated by the skin. In mice, UV exposure increases hypothalamus-pituitary-gonadal axis hormone levels, resulting in enhanced ovary size, extended estrus days, and anti-Mullerian hormone (AMH) expression. It likewise enhances the sexual responsiveness and attractiveness of females and male-female interactions of both males and females. Conditional knockout of p53 specifically in skin keratinocytes abolished UV’s effects. In humans, UV exposure enhanced romantic passion in both genders increased testosterone levels in men. Our data, revealing that UVB triggers a skin-brain-gonadal axis through skin p53 activation, offers therapeutic opportunities for sex-steroid-related dysfunctions. We speculate that during human furless skin evolution, the skin became the front-line regulator of the response to UVB.
Project description:Bazedoxifene and conjugated estrogens (CE+BZA) combination has been shown to prevent visceral adiposity and weight gain after menopause. However, its interaction with the microbiota has yet to be examined. In the present study, we use several –omics technologies to characterize the effects of various estrogens on the health of gut-liver axis. As reported in previous studies, CE+BZA combination is very effective at preventing ovariectomy-induced weight gain in mice fed a high-fat diet. Additionally, CE+BZA induces unique liver transcriptomic and blood metabolite profiles compared to estradiol, conjugated estrogens alone, and bazedoxifene alone. Several pathways and metabolites influenced are associated with lower rates of inflammation and overall benefits to gut and liver health. Finally, microbiome analysis shows that several bacterial species that potentially metabolize estrogens and affect their half-life in the body were significantly changed in CE+BZA treated mice. Our findings indicate a possible link between certain estrogens and gut microbiome and suggest a metabolic benefit of estrogens through manipulation of the gut-liver axis.
Project description:Bazedoxifene and conjugated estrogens (CE+BZA) combination has been shown to prevent visceral adiposity and weight gain after menopause. However, its interaction with the microbiota has yet to be examined. In the present study, we use several –omics technologies to characterize the effects of various estrogens on the health of gut-liver axis. As reported in previous studies, CE+BZA combination is very effective at preventing ovariectomy-induced weight gain in mice fed a high-fat diet. Additionally, CE+BZA induces unique liver transcriptomic and blood metabolite profiles compared to estradiol, conjugated estrogens alone, and bazedoxifene alone. Several pathways and metabolites influenced are associated with lower rates of inflammation and overall benefits to gut and liver health. Finally, microbiome analysis shows that several bacterial species that potentially metabolize estrogens and affect their half-life in the body were significantly changed in CE+BZA treated mice. Our findings indicate a possible link between certain estrogens and gut microbiome and suggest a metabolic benefit of estrogens through manipulation of the gut-liver axis.
Project description:The gut and liver are recognized to mutually communicate through the biliary tract, portal vein and systemic circulation, but it remains unclear how this gut-liver axis regulates intestinal physiology. Through hepatectomy, transcriptomic and proteomic profiling, we identified pigment epithelium-derived factor (PEDF), a liver-derived soluble Wnt inhibitor, that restrains intestinal stem cell (ISC) hyperproliferation to maintain gut homeostasis by suppressing the Wnt/b-catenin signaling pathway. Further, we found that microbial danger signals occurring as a result of intestinal inflammation can be sensed by the liver to repress PEDF production via peroxisome proliferator-activated receptor-a (PPARa), liberating ISC proliferation to accelerate tissue repair in the gut. Finally, treatment of mice with fenofibrate, a clinical agent of PPARa agonist for hypolipidemia enhances the susceptibility of colitis via PEDF activity. Therefore, we have identified a distinct role for PEDF in calibrating ISC expansion for intestinal homeostasis via reciprocal interactions between the gut and liver.
Project description:Barrier integrity is central to the maintenance of a healthy immunological homeostasis. Impaired skin barrier function is linked with enhanced allergen sensitization and the development of diseases such as atopic dermatitis (AD), which can precede the development of other allergic diseases such as food allergies and asthma. Epidemiological evidence indicates that children suffering from allergies have lower levels of dietary fibre-derived short-chain fatty acids (SCFA). Using an experimental model of AD, we report that a fermentable fibre-rich diet alleviates AD severity and systemic allergen sensitization. The gut-skin axis underpins this phenomenon through SCFA, which strengthen skin barrier integrity by altering mitochondrial metabolism of epidermal keratinocytes. SCFA promote keratinocyte differentiation and the production of key structural lipids, resulting in enhanced barrier function. Our results demonstrate that dietary fibre and SCFA mitigate AD by improving barrier integrity, ultimately limiting early systemic allergen sensitization and development of disease.