Xenobiotic and dietary compounds with hormone-like activity can disrupt endocrine signaling pathways that play important roles during perinatal differentiation and result in alterations that are not apparent until later in life. Evidence implicates developmental exposure to environmental hormone-mimics with a growing list of health problems. Obesity is currently receiving needed attention since it has potential to overwhelm health systems worldwide with associated illnesses such as diabetes and cardiovascular disease. Here, we review the literature that proposes an association of exposure to environmental endocrine disrupting chemicals with the development of obesity. We describe an animal model of developmental exposure to diethylstilbestrol (DES), a potent perinatal endocrine disruptor with estrogenic activity, to study mechanisms involved in programming an organism for obesity. This experimental animal model provides an example of the growing scientific field termed "the developmental origins of adult disease" and suggests new targets of abnormal programming by endocrine disrupting chemicals.

BackgroundIn vivo studies have demonstrated the ability of multi-walled carbon nanotubes (MWCNT) to induce airway remodeling, a key feature of chronic respiratory diseases like asthma and chronic obstructive pulmonary disease. However, the mechanism leading to remodeling is poorly understood. Particularly, there is limited insight about the role of airway epithelial injury in these changes.ObjectivesWe investigated the mechanism of MWCNT-induced primary human bronchial epithelial (HBE) cell injury and its contribution in inducing a profibrotic response.MethodsPrimary HBE cells were exposed to thoroughly characterized MWCNTs (1.5-24 μg/mL equivalent to 0.37-6.0 μg/cm2) and MRC-5 human lung fibroblasts were exposed to 1:4 diluted conditioned medium from these cells. Flow cytometry, ELISA, immunostainings/immunoblots and PCR analyses were employed to study cellular mechanisms.ResultsMWCNT induced NLRP3 inflammasome dependent pyroptosis in HBE cells in a time- and dose-dependent manner. Cell death and cytokine production were significantly reduced by antioxidants, siRNA to NLRP3, a caspase-1 inhibitor (z-WEHD-FMK) or a cathepsin B inhibitor (CA-074Me). Conditioned medium from MWCNT-treated HBE cells induced significant increase in mRNA expression of pro-fibrotic markers (TIMP-1, Tenascin-C, Procollagen 1, and Osteopontin) in human lung fibroblasts, without a concomitant change in expression of TGF-beta. Induction of pro-fibrotic markers was significantly reduced when IL-1β, IL-18 and IL-8 neutralizing antibodies were added to the conditioned medium or when conditioned medium from NLRP3 siRNA transfected HBE cells was used.ConclusionsTaken together these results demonstrate induction of a NLRP3 inflammasome dependent but TGF-beta independent pro-fibrotic response after MWCNT exposure.

Dietary substances and xenobiotic compounds with hormone-like activity can disrupt the programming of endocrine signaling pathways that are established during perinatal differentiation. The consequences of this disruption may not be apparent until later in life but increasing evidence implicates developmental exposure to environmental hormone-mimics with a growing list of adverse health effects including reproductive problems and increased cancer risks. Obesity has recently been proposed to be yet another adverse health consequence of exposure to endocrine disrupting substances during development. There is a renewed focus on identifying contributions of environmental factors to the development of obesity since it is reaching worldwide epidemic proportions, and this disease has the potential to overwhelm healthcare systems with associated illnesses such as diabetes and cardiovascular disease. Here, we review the literature that proposes an association of perinatal exposure to endocrine disrupting chemicals, in particular those with estrogenic activity, with the development of obesity later in life. We further describe an animal model of developmental exposure to diethylstilbestrol (DES) to study mechanisms involved in programming for obesity. Our experimental data support the idea that adipocytes and the mechanisms involved in weight homeostasis are novel targets of abnormal programming of environmental estrogens, some of which are found in our foods as naturally occurring substances or inadvertently as contaminants.

No abstract