Endocrine Disruption and In Vitro Ecotoxicology: Recent Advances and Approaches

Author(s):  
Martin Wagner ◽  
Cornelia Kienle ◽  
Etiënne L. M. Vermeirssen ◽  
Jörg Oehlmann
2001 ◽  
Vol 36 (2) ◽  
pp. 319-330 ◽  
Author(s):  
Mark Servos ◽  
Don Bennie ◽  
Kent Burnison ◽  
Philippa Cureton ◽  
Nicol Davidson ◽  
...  

Abstract A number of biological responses and multigenerational effects, mediated through the disruption of endocrine systems, have been observed in biota exposed to relatively low concentrations of environmental contaminants. These types of responses need to be considered within a weight of evidence approach in our risk assessment and risk management frameworks. However, including endocrine responses in an environmental risk assessment introduces a number of uncertainties that must be considered. A risk assessment of nonylphenol and nonylphenol polyethoxylates (NP/NPE) is used as a case study to demonstrate the sources and magnitude of some of the uncertainties associated with using endocrine disruption as an assessment endpoint. Even with this relatively well studied group of substances, there are substantial knowledge gaps which contribute to the overall uncertainties, limiting the interpretation within the risk assessment. The uncertainty of extrapolating from in vitro or biochemical responses to higher levels of organization or across species is not well understood. The endocrine system is very complex and chemicals can interact or interfere with the normal function of endocrine systems in a number of ways (e.g., receptors, hormones) which may or may not result in an adverse responses in the whole organism. Using endocrine responses can lead to different conclusions than traditional endpoints due to a variety of factors, such as differences in relative potencies of chemicals for specific endpoints (e.g., receptor binding versus chronic toxicity). The uncertainties can also be considerably larger and the desirability of using endocrine endpoints should be carefully evaluated. Endocrine disruption is a mode of action and not a functional endpoint and this needs to be considered carefully in the problem formulation stage and the interpretation of the weight of evidence.


2021 ◽  
Vol 11 (5) ◽  
pp. 336
Author(s):  
Mohammed Ghiboub ◽  
Ahmed M. I. Elfiky ◽  
Menno P. J. de Winther ◽  
Nicola R. Harker ◽  
David F. Tough ◽  
...  

Histone deacetylases (HDACs) and bromodomain-containing proteins (BCPs) play a key role in chromatin remodeling. Based on their ability to regulate inducible gene expression in the context of inflammation and cancer, HDACs and BCPs have been the focus of drug discovery efforts, and numerous small-molecule inhibitors have been developed. However, dose-limiting toxicities of the first generation of inhibitors, which typically target multiple HDACs or BCPs, have limited translation to the clinic. Over the last decade, an increasing effort has been dedicated to designing class-, isoform-, or domain-specific HDAC or BCP inhibitors, as well as developing strategies for cell-specific targeted drug delivery. Selective inhibition of the epigenetic modulators is helping to elucidate the functions of individual epigenetic proteins and has the potential to yield better and safer therapeutic strategies. In accordance with this idea, several in vitro and in vivo studies have reported the ability of more selective HDAC/BCP inhibitors to recapitulate the beneficial effects of pan-inhibitors with less unwanted adverse events. In this review, we summarize the most recent advances with these strategies, discussing advantages and limitations of these approaches as well as some therapeutic perspectives, focusing on autoimmune and inflammatory diseases.


2007 ◽  
Vol 88 (6) ◽  
pp. 1643-1655 ◽  
Author(s):  
Jeanmarie Verchot-Lubicz ◽  
Chang-Ming Ye ◽  
Devinka Bamunusinghe

Recent advances in potexvirus research have produced new models describing virus replication, cell-to-cell movement, encapsidation, R gene-mediated resistance and gene silencing. Interactions between distant RNA elements are a central theme in potexvirus replication. The 5′ non-translated region (NTR) regulates genomic and subgenomic RNA synthesis and encapsidation, as well as virus plasmodesmal transport. The 3′ NTR regulates both plus- and minus-strand RNA synthesis. How the triple gene-block proteins interact for virus movement is still elusive. As the potato virus X (PVX) TGBp1 protein gates plasmodesmata, regulates virus translation and is a suppressor of RNA silencing, further research is needed to determine how these properties contribute to propelling virus through the plasmodesmata. Specifically, TGBp1 suppressor activity is required for virus movement, but how the silencing machinery relates to plasmodesmata is not known. The TGBp2 and TGBp3 proteins are endoplasmic reticulum (ER)-associated proteins required for virus movement. TGBp2 associates with ER-derived vesicles that traffic along the actin network. Future research will determine whether the virus-induced vesicles are cytopathic structures regulating events along the ER or are vehicles carrying virus to the plasmodesmata for transfer into neighbouring cells. Efforts to assemble virions in vitro identified a single-tailed particle (STP) comprising RNA, coat protein (CP) and TGBp1. It has been proposed that TGBp1 aids in transport of virions or STP between cells and ensures translation of RNA in the receiving cells. PVX is also a tool for studying Avr–R gene interactions and gene silencing in plants. The PVX CP is the elicitor for the Rx gene. Recent reports of the PVX CP reveal how CP interacts with the Rx gene product.


2021 ◽  
Vol 71 (1) ◽  
pp. 17-32 ◽  
Author(s):  
Zvonimir Petric ◽  
Julia Ružić ◽  
Irena Žuntar

AbstractEffects of paraben toxicity, i.e., endocrine-disruption properties, are in the focus of researchers for decades, but still – they are a hot subject of debate. Parabens are aliphatic esters of p-hydroxybenzoic acid, which are widely used as antimicrobial agents for the preservation of cosmetics, pharmaceuticals and foods. Mostly used parabens are methyl-, ethyl-, propyl- and butylparaben. Although the toxicity of parabens is reported in animals and in in vitro studies, it cannot be taken for granted when discussing hazards for human health due to an unrealistic exposure -safety profile. Many studies have demonstrated that parabens are non-teratogenic, non-mutagenic, non-carcinogenic and the real evidence for their toxicity in humans has not been established. For now, methyl-, ethyl- and propylparaben are considered safe for use in cosmetics and pharmaceuticals within the recommended range of doses. Regarding alternatives for parabens, a variety of approaches have been proposed, but every substitute would need to be tested rigorously for toxicity and safety.


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