GladiaTOX: GLobal Assessment of Dose-IndicAtor in TOXicology.

Summary: GladiaTOX R package is an open-source, flexible solution to high-content screening data processing and reporting in biomedical research. GladiaTOX takes advantage of the 'tcpl' core functionalities and provides a number of extensions: it provides a web-service solution to fetch raw data; it computes severity scores and exports ToxPi formatted files; furthermore it contains a suite of functionalities to generate PDF reports for quality control and data processing.

Availability And Implementation: GladiaTOX R package (bioconductor).

In vitro systems toxicology-based assessment of the potential modified risk tobacco product CHTP 1.2 for vascular inflammation- and cytotoxicity-associated mechanisms promoting adhesion of monocytic cells to human coronary arterial endothelial cells.

Cigarette smoking causes cardiovascular diseases. Heating tobacco instead of burning it reduces the amount of toxic compounds in the aerosol and may exert a reduced impact on health compared with cigarette smoke. Aqueous extract from the aerosol of a potential modified risk tobacco product, the Carbon Heated Tobacco Product (CHTP) 1.

High Content Screening Analysis to Evaluate the Toxicological Effects of Harmful and Potentially Harmful Constituents (HPHC).

Cigarette smoke (CS) is a major risk factor for cardiovascular and lung diseases. Because CS is a complex aerosol containing more than 7,000 chemicals it is challenging to assess the contributions of individual constituents to its overall toxicity. Toxicological profiles of individual constituents as well as mixtures can be however established in vitro, by applying high through-put screening tools, which enable the profiling of Harmful and Potentially Harmful Constituents (HPHCs) of tobacco smoke, as defined by the U.

A framework for in vitro systems toxicology assessment of e-liquids.

Various electronic nicotine delivery systems (ENDS), of which electronic cigarettes (e-cigs) are the most recognized prototype, have been quickly gaining ground on conventional cigarettes because they are perceived as less harmful. Research assessing the potential effects of ENDS exposure in humans is currently limited and inconclusive. New products are emerging with numerous variations in designs and performance parameters within and across brands.

In Vitro Systems Toxicology Assessment of a Candidate Modified Risk Tobacco Product Shows Reduced Toxicity Compared to That of a Conventional Cigarette.

Cigarette smoke increases the risk for respiratory and other diseases. Although smoking prevalence has declined over the years, millions of adults choose to continue to smoke. Modified risk tobacco products (MRTPs) are potentially valuable tools for adult smokers that are unwilling to quit their habit.

Systems toxicology approaches enable mechanistic comparison of spontaneous and cigarette smoke-related lung tumor development in the A/J mouse model.

The A/J mouse is highly susceptible to lung tumor induction and has been widely used as a screening model in carcinogenicity testing and chemoprevention studies. However, the A/J mouse model has several disadvantages. Most notably, it develops lung tumors spontaneously.

Systems biology approach for evaluating the biological impact of environmental toxicants in vitro.

Exposure to cigarette smoke is a leading cause of lung diseases including chronic obstructive pulmonary disease and cancer. Cigarette smoke is a complex aerosol containing over 6000 chemicals and thus it is difficult to determine individual contributions to overall toxicity as well as the molecular mechanisms by which smoke constituents exert their effects. We selected three well-known harmful and potentially harmful constituents (HPHCs) in tobacco smoke, acrolein, formaldehyde and catechol, and established a high-content screening method using normal human bronchial epithelial cells, which are the first bronchial cells in contact with cigarette smoke.

BRCA1 loss activates cathepsin L-mediated degradation of 53BP1 in breast cancer cells.

Loss of 53BP1 rescues BRCA1 deficiency and is associated with BRCA1-deficient and triple-negative breast cancers (TNBC) and with resistance to genotoxic drugs. The mechanisms responsible for decreased 53BP1 transcript and protein levels in tumors remain unknown. Here, we demonstrate that BRCA1 loss activates cathepsin L (CTSL)-mediated degradation of 53BP1.

Regulating the levels of key factors in cell cycle and DNA repair: new pathways revealed by lamins.

Spatial and temporal organization of the genome represents an additional step in the regulation of nuclear functions. The nuclear lamina, a polymeric meshwork formed by lamins (A/C and B type) and lamin-associated proteins, plays a key role in the maintenance of genome localization, structure and function. Specifically, mutations in the LMNA gene encoding lamins A/C or changes in its expression, either upregulation or silencing, are associated with defects in DNA replication, transcription and repair, as well as alterations in epigenetic modifications of chromatin.

A new pathway that regulates 53BP1 stability implicates cathepsin L and vitamin D in DNA repair.

Genomic instability due to telomere dysfunction and defective repair of DNA double-strand breaks (DSBs) is an underlying cause of ageing-related diseases. 53BP1 is a key factor in DNA DSBs repair and its deficiency is associated with genomic instability and cancer progression. Here, we uncover a novel pathway regulating the stability of 53BP1.

A dual role for A-type lamins in DNA double-strand break repair.

A-type lamins are emerging as regulators of nuclear organization and function. Changes in their expression are associated with cancer and mutations are linked to degenerative diseases -laminopathies-. Although a correlation exists between alterations in lamins and genomic instability, the molecular mechanisms remain largely unknown.

Nurturing the genome: A-type lamins preserve genomic stability.

A-type lamins provide a scaffold for tethering chromatin and protein complexes regulating nuclear structure and function. Interest in lamins increased after mutations in the LMNA gene were found to be associated with a variety of human disorders termed laminopathies. These include muscular dystrophy, cardiomyopathy, lipodystrophy, peripheral neuropathy and premature aging syndromes such as progeria.

The mTOR inhibitor rapamycin suppresses DNA double-strand break repair.

mTOR (mammalian target of rapamycin) signaling plays a key role in the development of many tumor types. Therefore, mTOR is an attractive target for cancer therapeutics. Although mTOR inhibitors are thought to have radiosensitization activity, the molecular bases remain largely unknown.

Lanthanum activates calcium-sensing receptor and enhances sensitivity to calcium.

Background: The aim of this study was to investigate whether nanomolar concentrations of lanthanum could influence the calcium-sensing receptor (CaSR) response.

Methods: Embryonic kidney (HEK-293) cells transiently transfected with the human CaSR were used to test the ability of lanthanum to activate the CaSR, either alone or in combination with calcium. CaSR activation was measured by flow cytometry.

Residue 826 in the calcium-sensing receptor is implicated in the response to calcium and to R-568 calcimimetic compound.

Within the extracellular loops of the seven-transmembrane domain of the calcium-sensing receptor (CaR) there is a region (I819-E837) relevant for calcimimetic activity. As the naturally occurring variant Ala826Thr is within this important region, it may be postulated that this change may influence the CaR response to calcium and R-568. Human embryonic kidney (HEK-293) cells transiently transfected with three different human CaRs (wild-type [A826], variant allele [T826], and artificial mutant [W826]) were used to test the ability of calcium alone or in combination with the calcimimetic R-568 to modulate CaR activity.

The role of RPA2 phosphorylation in homologous recombination in response to replication arrest.

Failure to reactivate stalled or collapsed DNA replication forks is a potential source of genomic instability. Homologous recombination (HR) is a major mechanism for repairing the DNA damage resulting from replication arrest. The single-strand DNA (ssDNA)-binding protein, replication protein A (RPA), plays a major role in multiple processes of DNA metabolism.

Loss of A-type lamins and genomic instability.

Research performed in the last few years has revealed important roles for the spatial and temporal organization of the genome on genome function and integrity. A challenge in the field is to determine the molecular mechanisms involved in the organization of genome function. A-type lamins, key structural components of the nucleus, have been implicated in the maintenance of nuclear architecture and chromatin structure.

Novel roles for A-type lamins in telomere biology and the DNA damage response pathway.

A-type lamins are intermediate filament proteins that provide a scaffold for protein complexes regulating nuclear structure and function. Mutations in the LMNA gene are linked to a variety of degenerative disorders termed laminopathies, whereas changes in the expression of lamins are associated with tumourigenesis. The molecular pathways affected by alterations of A-type lamins and how they contribute to disease are poorly understood.

Telomere recombination requires the MUS81 endonuclease.

Telomerase-negative cancer cells maintain their telomeres through the alternative lengthening of telomeres (ALT) pathway. Although a growing body of evidence demonstrates that the ALT mechanism is a post-replicative telomere recombination process, molecular details of this pathway are largely unknown. Here we demonstrate that MUS81, a DNA structure specific recombination endonuclease, has a key role in the maintenance of telomeres in human ALT cells.

Simultaneous changes in the calcium-sensing receptor and the vitamin D receptor under the influence of calcium and calcitriol.

Background: The regulatory mechanisms of parathyroid hormone (PTH) synthesis are complex, involving calcium, calcitriol, the calcium-sensing receptor (CaR) and the vitamin D receptor (VDR). In this study, the effects of calcium and calcitriol on the simultaneous expression of CaR and VDR mRNA and protein levels were assessed in parathyroid glands cultured in vitro.

Methods: Parathyroid glands (N = 424) were removed and cultured for 24 h to study the effect of calcium on the CaR, VDR and PTH.

EGFR activation increases parathyroid hyperplasia and calcitriol resistance in kidney disease.

Calcitriol, acting through vitamin D receptors (VDR) in the parathyroid, suppresses parathyroid hormone synthesis and cell proliferation. In secondary hyperparathyroidism (SH), VDR content is reduced as hyperplasia becomes more severe, limiting the efficacy of calcitriol. In a rat model of SH, activation of the EGF receptor (EGFR) by TGF-alpha is required for the development of parathyroid hyperplasia, but the relationship between EGFR activation and reduced VDR content is unknown.

Viability and functionality of fresh and cryopreserved human hyperplastic parathyroid tissue tested in vitro.

Background/aims: This study aimed to test the viability and functionality of fresh and cryopreserved human hyperplastic parathyroid glands cultured in vitro.

Methods: Small fragments of 18 parathyroid glands from 18 patients with secondary hyperparathyroidism were cultured in vitro, freshly or after cryopreservation, during 60 h. Cell viability and functionality of the parathyroid fragments exposed to calcium and calcitriol were studied.