Project description:We used microarrays to investigate gene expression changes in leukemic cells from Pax5+/- mice treated with antibiotics. Precursor B cell acute lymphoblastic leukemia (pB-ALL), the most common type of childhood leukemia, is frequently characterized by the cooperation of a genetic predisposition acquired in utero and secondary oncogenic events taking place only in a fraction of predisposed children after birth. Although predisposition can be detected at birth, it is currently unknown which factors determine the development of overt leukemia in genetic carriers and how this can be potentially prevented. Experimental studies have shown that infectious stimuli promote disease onset in genetically predisposed mice. Here, we analyzed the impact of the microbiome on leukemogenesis in a mouse model (Pax5+/- mice) that faithfully mimicks genetic predisposition and leukemogenesis of human pB-ALL related to the synergy of genetic predisposition and exposure to a natural infectious environment. Employing 16S rRNA sequencing and machine learning we can accurately predict a distinct gut microbiome which is determined by a specific constitutional genetic variant. Deprivation of the gut microbiome by antibiotic treatment enhanced pB-ALL development in Pax5+/- predisposed (63% vs. 22%) but not in wildtype mice (0%). This finding was observed in the presence but also -to a lesser extent- in the absence of a natural, infectious environment (48%). The composition of the gut microbiome constitutes a biomarker signature and allows to identify specifically those Pax5+/- mice that developed leukemia. This indicates that the gut microbiome can be used to identify carriers at risk to develop leukemia and to reduce this risk by early-life interventions.
Project description:Estrogens are important for metabolic health. Individuals with low levels of circulating estrogens, including men and postmenopausal women, exhibit an elevated risk for developing obesity-associated metabolic syndromes. Chronic low-grade inflammation in the visceral adipose tissue (VAT) is a major contributor to metabolic dysfunction during obesity. Regulatory T cells (Tregs) in the VAT limit tissue inflammation and protect against obesity-associated metabolic disease. In this study, we identify opposing roles of estrogen receptor α (ERα) in regulating VAT Tregs in female mice under steady-state and obese conditions. At steady state, ERα restrained the age-dependent clonal expansion of specific VAT Treg subsets expressing the IL-33 receptor ST2. However, during obesity, ERα-deficiency predisposed females to the loss of ST2+ VAT Tregs, exacerbating VAT inflammation and insulin resistance. These findings indicate that ERα signaling protects against obesity-induced metabolic diseases by preserving metabolically protective ST2+ VAT Treg subsets, and the loss of this protection may contribute to the heightened metabolic risk in estrogen-deficient individuals.
Project description:Estrogens are important for metabolic health. Individuals with low levels of circulating estrogens, including men and postmenopausal women, exhibit an elevated risk for developing obesity-associated metabolic syndromes. Chronic low-grade inflammation in the visceral adipose tissue (VAT) is a major contributor to metabolic dysfunction during obesity. Regulatory T cells (Tregs) in the VAT limit tissue inflammation and protect against obesity-associated metabolic disease. In this study, we identify opposing roles of estrogen receptor α (ERα) in regulating VAT Tregs in female mice under steady-state and obese conditions. At steady state, ERα restrained the age-dependent clonal expansion of specific VAT Treg subsets expressing the IL-33 receptor ST2. However, during obesity, ERα-deficiency predisposed females to the loss of ST2+ VAT Tregs, exacerbating VAT inflammation and insulin resistance. These findings indicate that ERα signaling protects against obesity-induced metabolic diseases by preserving metabolically protective ST2+ VAT Treg subsets, and the loss of this protection may contribute to the heightened metabolic risk in estrogen-deficient individuals.