The spatial clustering of obesity: does the built environment matter?

BACKGROUND

Obesity rates in the USA show distinct geographical patterns. The present study used spatial cluster detection methods and individual-level data to locate obesity clusters and to analyse them in relation to the neighbourhood built environment.

METHODS

The 2008-2009 Seattle Obesity Study provided data on the self-reported height, weight, and sociodemographic characteristics of 1602 King County adults. Home addresses were geocoded. Clusters of high or low body mass index were identified using Anselin's Local Moran's I and a spatial scan statistic with regression models that searched for unmeasured neighbourhood-level factors from residuals, adjusting for measured individual-level covariates. Spatially continuous values of objectively measured features of the local neighbourhood built environment (SmartMaps) were constructed for seven variables obtained from tax rolls and commercial databases.

RESULTS

Both the Local Moran's I and a spatial scan statistic identified similar spatial concentrations of obesity. High and low obesity clusters were attenuated after adjusting for age, gender, race, education and income, and they disappeared once neighbourhood residential property values and residential density were included in the model.

CONCLUSIONS

Using individual-level data to detect obesity clusters with two cluster detection methods, the present study showed that the spatial concentration of obesity was wholly explained by neighbourhood composition and socioeconomic characteristics. These characteristics may serve to more precisely locate obesity prevention and intervention programmes.

Quantitative high-throughput profiling of environmental chemicals and drugs that modulate farnesoid X receptor

The farnesoid X receptor (FXR) regulates the homeostasis of bile acids, lipids, and glucose. Because endogenous chemicals bind and activate FXR, it is important to examine which xenobiotic compounds would disrupt normal receptor function. We used a cell-based human FXR β-lactamase (Bla) reporter gene assay to profile the Tox21 10K compound collection of environmental chemicals and drugs. Structure-activity relationships of FXR-active compounds revealed by this screening were then compared against the androgen receptor, estrogen receptor α, peroxisome proliferator-activated receptors δ and γ, and the vitamin D receptor. We identified several FXR-active structural classes including anthracyclines, benzimidazoles, dihydropyridines, pyrethroids, retinoic acids, and vinca alkaloids. Microtubule inhibitors potently decreased FXR reporter gene activity. Pyrethroids specifically antagonized FXR transactivation. Anthracyclines affected reporter activity in all tested assays, suggesting non-specific activity. These results provide important information to prioritize chemicals for further investigation, and suggest possible modes of action of compounds in FXR signaling.

Conduction control at ferroic domain walls via external stimuli

Intriguing functionalities at nano-sized domain walls have recently spawned a new paradigm for developing novel nanoelectronics due to versatile characteristics. In this study, we explore a new scenario to modulate the local conduction of ferroic domain walls. Three controlling parameters, i.e., external electrical field, magnetic field and light, are introduced to the 90° domain walls (90° DWs) of BiFeO₃. Electrical modulation is realized by electrical transport, where the mobility of 90° DWs can be altered by gating voltage. We further use the ferromagnetic/antiferromagnetic coupling to reveal the inherent magnetism at the DWs. With an established magnetic nature, magnetotransport has been conducted to introduce magnetic controlling parameter, where a giant positive magnetoresistance change can be observed up to 200%. In addition, light modulated conduction, a core factor for multifunctional applications, is successfully demonstrated (current enhancement by a factor of 2 with 11 W white lamp). These results offer new insights to discover the tunability of domain wall nanoelectronics.

Disrupted topological properties of brain white matter networks in left temporal lobe epilepsy: a diffusion tensor imaging study

Mesial temporal lobe epilepsy (mTLE) is the most common drug-refractory focal epilepsy in adults. Although previous functional and morphological studies have revealed abnormalities in the brain networks of mTLE, the topological organization of the brain white matter (WM) networks in mTLE patients is still ambiguous. In this study, we constructed brain WM networks for 14 left mTLE patients and 22 age- and gender-matched normal controls using diffusion tensor tractography and estimated the alterations of network properties in the mTLE brain networks using graph theoretical analysis. We found that networks for both the mTLE patients and the controls exhibited prominent small-world properties, suggesting a balanced topology of integration and segregation. However, the brain WM networks of mTLE patients showed a significant increased characteristic path length but significant decreased global efficiency, which indicate a disruption in the organization of the brain WM networks in mTLE patients. Moreover, we found significant between-group differences in the nodal properties in several brain regions, such as the left superior temporal gyrus, left hippocampus, the right occipital and right temporal cortices. The robustness analysis showed that the results were likely to be consistent for the networks constructed with different definitions of node and edge weight. Taken together, our findings may suggest an adverse effect of epileptic seizures on the organization of large-scale brain WM networks in mTLE patients.

Predictive endocrine testing in the 21st century using in vitro assays of estrogen receptor signaling responses

Thousands of environmental chemicals are subject to regulatory review for their potential to be endocrine disruptors (ED). In vitro high-throughput screening (HTS) assays have emerged as a potential tool for prioritizing chemicals for ED-related whole-animal tests. In this study, 1814 chemicals including pesticide active and inert ingredients, industrial chemicals, food additives, and pharmaceuticals were evaluated in a panel of 13 in vitro HTS assays. The panel of in vitro assays interrogated multiple end points related to estrogen receptor (ER) signaling, namely binding, agonist, antagonist, and cell growth responses. The results from the in vitro assays were used to create an ER Interaction Score. For 36 reference chemicals, an ER Interaction Score >0 showed 100% sensitivity and 87.5% specificity for classifying potential ER activity. The magnitude of the ER Interaction Score was significantly related to the potency classification of the reference chemicals (p < 0.0001). ERα/ERβ selectivity was also evaluated, but relatively few chemicals showed significant selectivity for a specific isoform. When applied to a broader set of chemicals with in vivo uterotrophic data, the ER Interaction Scores showed 91% sensitivity and 65% specificity. Overall, this study provides a novel method for combining in vitro concentration response data from multiple assays and, when applied to a large set of ER data, accurately predicted estrogenic responses and demonstrated its utility for chemical prioritization.

Drug repurposing screen identifies lestaurtinib amplifies the ability of the poly (ADP-ribose) polymerase 1 inhibitor AG14361 to kill breast cancer associated gene-1 mutant and wild type breast cancer cells

Introduction

Breast cancer is a devastating disease that results in approximately 40,000 deaths each year in the USA. Current drug screening and chemopreventatitive methods are suboptimal, due in part to the poor specificity of compounds for cancer cells. Poly (ADP-ribose) polymerase 1 (PARP1) inhibitor (PARPi)-mediated therapy is a promising approach for familial breast cancers caused by mutations of breast cancer-associated gene-1 and -2 (BRCA1/2), yet drug resistance frequently occurs during the treatment. Moreover, PARPis exhibit very little effect on cancers that are proficient for DNA repair and clinical efficacy for PARPis as single-agent therapies has yet to be illustrated.

Methods

Using a quantitative high-throughput screening approach, we screened a library containing 2,816 drugs, most of which are approved for human or animal use by the Food and Drug Administration (FDA) or other countries, to identify compounds that sensitize breast cancer cells to PARPi. After initial screening, we performed further cellular and molecular analysis on lestaurtinib, which is an orally bioavailable multikinase inhibitor and has been used in clinical trials for myeloproliferative disorders and acute myelogenous leukemia.

Results

Our study indicated that lestaurtinib is highly potent against breast cancers as a mono-treatment agent. It also strongly enhanced the activity of the potent PARPi AG14361 on breast cancer cell growth both in vitro and in vivo conditions. The inhibition of cancer growth is measured by increased apoptosis and reduced cell proliferation. Consistent with this, the treatment results in activation of caspase 3/7, and accumulation of cells in the G2 phase of the cell cycle, irrespective of their BRCA1 status. Finally, we demonstrated that AG14361 inhibits NF-κB signaling, which is further enhanced by lestaurtinib treatment.

Conclusions

Lestaurtinib amplifies the ability of the PARP1 inhibitor AG14361 to kill BRCA1 mutant and wild-type breast cancer cells, at least in part, by inhibiting NF-κB signaling. Each of these drugs has been approved for clinical trials for several different cancers, thus, their combination treatment should be applicable for a breast cancer trial in the future.

PTEN degradation after ischemic stroke: a double-edged sword

Tumor suppressor phosphatase and tensin homolog (PTEN) is highly expressed in neurons and PTEN inhibition has been reported to be neuroprotective against ischemic stroke in experimental models. On the other hand, PTEN deletion has been shown to lead to cognitive impairment. In the current study, we examined the expression and functions of PTEN in an ischemic stroke rodent model. We found rapid S-nitrosylation and degradation of PTEN after cerebral ischemia/reperfusion injury. PTEN degradation leads to activation of Akt. PTEN partial deletion or PTEN inhibition increased the expression of GABAA receptor (GABAAR) γ2 subunit and enhanced GABAA receptor current. After cerebral ischemia, increased expression of GABAAR γ2 subunit was observed in the ischemia region and the penumbra area. We also observed PTEN loss in astrocytes after cerebral ischemia. Astrocytic PTEN partial knockout increased astrocyte activation and exacerbated ischemic damage. We speculated that ischemic stroke induced neuronal PTEN degradation, hence enhanced GABAA receptor-medicated neuronal activity inhibition which could attenuate excitotoxicity and provide neuroprotection during the acute phase after stroke, while inhibiting long-term functional recovery and contributing to vascular cognitive impairment after stroke. On the other hand, ischemic stroke induced astrocytic PTEN loss and enhanced ischemic damage and astrogliosis. Taken together, our study indicates that ischemic stroke induces rapid PTEN degradation in both neurons and astrocytes which play both protective and detrimental action in a spatiotemporal- and cell-type-dependent manner. Our study provides critical insight for targeting PTEN signaling pathway for stroke treatment.

Identification of novel PARP inhibitors using a cell-based TDP1 inhibitory assay in a quantitative high-throughput screening platform

Anti-cancer topoisomerase I (Top1) inhibitors (camptothecin and its derivatives irinotecan and topotecan, and indenoisoquinolines) induce lethal DNA lesions by stabilizing Top1-DNA cleavage complex (Top1cc). These lesions are repaired by parallel repair pathways including the tyrosyl-DNA phosphodiesterase 1 (TDP1)-related pathway and homologous recombination. As TDP1-deficient cells in vertebrates are hypersensitive to Top1 inhibitors, small molecules inhibiting TDP1 should augment the cytotoxicity of Top1 inhibitors. We developed a cell-based high-throughput screening assay for the discovery of inhibitors for human TDP1 using a TDP1-deficient chicken DT40 cell line (TDP1-/-) complemented with human TDP1 (hTDP1). Any compounds showing a synergistic effect with the Top1 inhibitor camptothecin (CPT) in hTDP1 cells should either be a TDP1-related pathway inhibitor or an inhibitor of alternate repair pathways for Top1cc. We screened the 400,000-compound Small Molecule Library Repository (SMLR, NIH Molecular Libraries) against hTDP1 cells in the absence or presence of CPT. After confirmation in a secondary screen using both hTDP1 and TDP1-/- cells in the absence or presence of CPT, five compounds were confirmed as potential TDP1 pathway inhibitors. All five compounds showed synergistic effect with CPT in hTDP1 cells, but not in TDP1-/- cells, indicating that the compounds inhibited a TDP1-related repair pathway. Yet, in vitro gel-based assay revealed that the five compounds did not inhibit TDP1 catalytic activity directly. We tested the compounds for their ability to inhibit poly(ADP-ribose)polymerase (PARP) because PARP inhibitors are known to potentiate the cytotoxicity of CPT by inhibiting the recruitment of TDP1 to Top1cc. Accordingly, we found that the five compounds inhibit catalytic activity of PARP by ELISA and Western blotting. We identified the most potent compound (Cpd1) that offers characteristic close to veliparib, a leading clinical PARP inhibitor. Cpd1 may represent a new scaffold for the development of PARP inhibitors.

Proteomics reveal energy metabolism and mitogen-activated protein kinase signal transduction perturbation in human Borna disease virus Hu-H1-infected oligodendroglial cells

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A human strain of BDV (BDV Hu-H1) was used to infect human oligodendroglial cells (OL cells).

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Energy metabolism was the most significantly altered pathway in BDV Hu-H1-infected OL cells.

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The Raf/MEK/ERK signaling cascade was significantly perturbed in BDV Hu-H1-infected OL cells.

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BDV Hu-H1caused constitutive activation of the ERK1/2 pathway, but cell proliferation was down-regulated at the same time.

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BDV Hu-H1 manages to down-regulate cell proliferation, in the presence of activated but not translocated ERK–RSK complex.

Borna disease virus (BDV) is a neurotropic, non-cytolytic RNA virus which replicates in the cell nucleus targeting mainly hippocampal neurons, but also astroglial and oligodendroglial cells in the brain. BDV is associated with a large spectrum of neuropsychiatric pathologies in animals. Its relationship to human neuropsychiatric illness still remains controversial. We could recently demonstrate that human BDV strain Hu-H1 promoted apoptosis and inhibited cell proliferation in a human oligodendroglial cell line (OL cells) whereas laboratory BDV strain V acted contrariwise. Here, differential protein expression between BDV Hu-H1-infected OL cells and non-infected OL cells was assessed through a proteomics approach, using two-dimensional electrophoresis followed by matrix-assisted laser desorption ionization-time of flight tandem mass spectrometry. A total of 63 differential host proteins were identified in BDV Hu-H1-infected OL cells compared to non-infected OL cells. We found that most changes referred to alterations related to the pentose phosphate pathway, glyoxylate and dicarboxylate metabolism, the tricarboxylic acid (TCA) cycle, and glycolysis /gluconeogenesis. By manual querying, two differential proteins were found to be associated with mitogen-activated protein kinase (MAPK) signal transduction. Five key signaling proteins of this pathway (i.e., p-Raf, p-MEK, p-ERK1/2, p-RSK, and p-MSK) were selected for Western blotting validation. p-ERK1/2 and p-RSK were found to be significantly up-regulated, and p-MSK was found to be significantly down-regulated in BDV Hu-H1-infected OL cells compared to non-infected OL cell. Although BDV Hu-H1 constitutively activated the ERK–RSK pathway, host cell proliferation and nuclear translocation of activated pERK in BDV Hu-H1-infected OL cells were impaired. These findings indicate that BDV Hu-H1 infection of human oligodendroglial cells significantly perturbs host energy metabolism, activates the downstream ERK–RSK complex of the Raf/MEK/ERK signaling cascade, and disturbs host cell proliferation possibly through impaired nuclear translocation of pERK, a finding which warrants further research.

Identification of thyroid hormone receptor active compounds using a quantitative high-throughput screening platform

To adapt the use of GH3.TRE-Luc reporter gene cell line for a quantitative high-throughput screening (qHTS) platform, we miniaturized the reporter gene assay to a 1536-well plate format. 1280 chemicals from the Library of Pharmacologically Active Compounds (LOPAC) and the National Toxicology Program (NTP) 1408 compound collection were analyzed to identify potential thyroid hormone receptor (TR) agonists and antagonists. Of the 2688 compounds tested, eight scored as potential TR agonists when the positive hit cut-off was defined at ≥10% efficacy, relative to maximal triiodothyronine (T₃) induction, and with only one of those compounds reaching ≥20% efficacy. One common class of compounds positive in the agonist assays were retinoids such as all-trans retinoic acid, which are likely acting via the retinoid-X receptor, the heterodimer partner with the TR. Five potential TR antagonists were identified, including the antiallergy drug tranilast and the anxiolytic drug SB 205384 but also some cytotoxic compounds like 5-fluorouracil. None of the inactive compounds were structurally related to T₃, nor had been reported elsewhere to be thyroid hormone disruptors, so false negatives were not detected. None of the low potency (>100µM) TR agonists resembled T₃ or T₄, thus these may not bind directly in the ligand-binding pocket of the receptor. For TR agonists, in the qHTS, a hit cut-off of ≥20% efficacy at 100 µM may avoid identification of positives with low or no physiological relevance. The miniaturized GH3.TRE-Luc assay offers a promising addition to the in vitro test battery for endocrine disruption, and given the low percentage of compounds testing positive, its high-throughput nature is an important advantage for future toxicological screening.

GOLPH3 is a novel marker of poor prognosis and a potential therapeutic target in human renal cell carcinoma

Background:

Golgi phosphoprotein 3 (GOLPH3) has been reported to be involved in the development of several human cancers. The present study was conducted to investigate the expression of GOLPH3 and its prognostic significance in renal cell carcinoma (RCC). Meanwhile, the function of GOLPH3 in human RCC was further investigated in cell culture models.

Methods:

Expression of GOLPH3 was examined in 43 fresh RCC tissues and paired adjacent normal renal tissues by real-time quantitative PCR and western blotting. Immunohistochemistry for GOLPH3 was performed on additional 218 RCC tissues. The clinical significance of GOLPH3 expression was analysed. Downregulation of GOLPH3 was performed using small-interfering RNA (siRNA) in Caki-1 and 786-O cells with high abundance of GOLPH3, and the effects of GOLPH3 silencing on cell proliferation, migration, invasion in vitro, and tumour growth in vivo were evaluated.

Results:

Expression of GOLPH3 was upregulated in the majority of the RCC clinical tissue specimens at both mRNA and protein levels. Clinicopathological analysis showed that GOLPH3 expression was significantly correlated with T stage (P<0.001), lymph-node status (P=0.003), distant metastasis (P<0.001), tumour-node-metastasis (TNM) stage (P<0.001), and Fuhman grade (P=0.001). Expression of GOLPH3 was inversely correlated with both overall and recurrence-free survival of RCC patients. Multivariate analysis showed that GOLPH3 expression was an independent prognostic indicator for patient's survival. Knockdown of the GOLPH3 expression reduced cell proliferation, anchorage-independent growth, migration, invasion, and tumour growth in xenograft model mice.

Conclusions:

These results suggest that GOLPH3 expression is likely to have important roles in RCC development and progression, and that GOLPH3 is a prognostic biomarker and a promising therapeutic target for RCC.

Detection of phospholipidosis induction: a cell-based assay in high-throughput and high-content format

Drug-induced phospholipidosis is characterized by the accumulation of intracellular phospholipids in cells exposed to cationic amphiphilic drugs. The appearance of unicentric or multicentric multilamellar bodies viewed under an electron microscope (EM) is the morphological hallmark of phospholipidosis. Although the EM method is the gold standard for detecting cellular phospholipidosis, this method has its drawbacks, including low throughput, high cost, and unsuitability for screening a large chemical library. In this study, a cell-based phospholipidosis assay has been developed using the LipidTOX Red reagent in HepG2 cells and miniaturized into a 1536-well plate format. To validate this assay for high-throughput screening (HTS), the LOPAC library of 1280 compounds was screened using a quantitative HTS platform. A group of known phospholipidosis inducers, such as amiodarone, propranolol, chlorpromazine, desipramine, promazine, clomipramine, and amitriptyline, was identified by the screen, consistent with previous reports. Several novel phospholipidosis inducers, including NAN-190, ebastine, GR127935, and cis-(Z)-flupentixol, were identified in this study and confirmed using the EM method. These results demonstrate that this assay can be used to evaluate and profile large numbers of chemicals for drug-induced phospholipidosis.

A novel chordoma xenograft allows in vivo drug testing and reveals the importance of NF-κB signaling in chordoma biology

Chordoma is a rare primary bone malignancy that arises in the skull base, spine and sacrum and originates from remnants of the notochord. These tumors are typically resistant to conventional chemotherapy, and to date there are no FDA-approved agents to treat chordoma. The lack of in vivo models of chordoma has impeded the development of new therapies for this tumor. Primary tumor from a sacral chordoma was xenografted into NOD/SCID/IL-2R γ-null mice. The xenograft is serially transplantable and was characterized by both gene expression analysis and whole genome SNP genotyping. The NIH Chemical Genomics Center performed high-throughput screening of 2,816 compounds using two established chordoma cell lines, U-CH1 and U-CH2B. The screen yielded several compounds that showed activity and two, sunitinib and bortezomib, were tested in the xenograft. Both agents slowed the growth of the xenograft tumor. Sensitivity to an inhibitor of IκB, as well as inhibition of an NF-κB gene expression signature demonstrated the importance of NF-κB signaling for chordoma growth. This serially transplantable chordoma xenograft is thus a practical model to study chordomas and perform in vivo preclinical drug testing.

Systematic study of mitochondrial toxicity of environmental chemicals using quantitative high throughput screening

A goal of the Tox21 program is to transit toxicity testing from traditional in vivo models to in vitro assays that assess how chemicals affect cellular responses and toxicity pathways. A critical contribution of the NIH Chemical Genomics center (NCGC) to the Tox21 program is the implementation of a quantitative high throughput screening (qHTS) approach, using cell- and biochemical-based assays to generate toxicological profiles for thousands of environmental compounds. Here, we evaluated the effect of chemical compounds on mitochondrial membrane potential in HepG2 cells by screening a library of 1,408 compounds provided by the National Toxicology Program (NTP) in a qHTS platform. Compounds were screened over 14 concentrations, and results showed that 91 and 88 compounds disrupted mitochondrial membrane potential after treatment for 1 or 5 h, respectively. Seventy-six compounds active at both time points were clustered by structural similarity, producing 11 clusters and 23 singletons. Thirty-eight compounds covering most of the active chemical space were more extensively evaluated. Thirty-six of the 38 compounds were confirmed to disrupt mitochondrial membrane potential using a fluorescence plate reader, and 35 were confirmed using a high content imaging approach. Among the 38 compounds, 4 and 6 induced LDH release, a measure of cytotoxicity, at 1 or 5 h, respectively. Compounds were further assessed for mechanism of action (MOA) by measuring changes in oxygen consumption rate, which enabled the identification of 20 compounds as uncouplers. This comprehensive approach allows for the evaluation of thousands of environmental chemicals for mitochondrial toxicity and identification of possible MOAs.

The Tox21 robotic platform for the assessment of environmental chemicals--from vision to reality

Since its establishment in 2008, the US Tox21 inter-agency collaboration has made great progress in developing and evaluating cellular models for the evaluation of environmental chemicals as a proof of principle. Currently, the program has entered its production phase (Tox21 Phase II) focusing initially on the areas of modulation of nuclear receptors and stress response pathways. During Tox21 Phase II, the set of chemicals to be tested has been expanded to nearly 10,000 (10K) compounds and a fully automated screening platform has been implemented. The Tox21 robotic system combined with informatics efforts is capable of screening and profiling the collection of 10K environmental chemicals in triplicate in a week. In this article, we describe the Tox21 screening process, compound library preparation, data processing, and robotic system validation.