High-Throughput cell-based immunofluorescence assays against influenza

A rapid drug discovery response to influenza outbreaks with the potential to reach pandemic status could help minimize the virus's impact by reducing the time to identify anti-influenza drugs. Although several anti-influenza strategies have been considered in the search for new drugs, only a few therapeutic agents are approved for clinical use. The cytopathic effect induced by the influenza virus in Madin Darby canine kidney (MDCK) cells has been widely used for high-throughput anti-influenza drug screening, but the fact that the MDCK cells are not human cells constitutes a disadvantage when searching for new therapeutic agents for human use. We have developed a highly sensitive cell-based imaging assay for the identification of inhibitors of influenza A and B virus that is high-throughput compatible using the A549 human cell line. The assay has also been optimized for the assessment of the neutralizing effect of anti-influenza antibodies in the absence of trypsin, which allows testing of purified antibodies and serum samples. This assay platform can be applied to full high-throughput screening campaigns or later stages requiring quantitative potency determinations for structure-activity relationships.

A BRET Ca2+ sensor enables high-throughput screening in the presence of background fluorescence

The intrinsic fluorescence of samples confounds the use of fluorescence-based sensors. This is of particular concern in high-throughput screening (HTS) applications using large chemical libraries containing intrinsically fluorescent compounds. To overcome this problem, we developed a bioluminescence resonance energy transfer (BRET) Ca2+ sensor, CalfluxCTN. We demonstrated that it reliably reported changes in intracellular Ca2+ concentrations evoked by an agonist and an antagonist of the human muscarinic acetylcholine receptor M1 (hM1R) even in the presence of the fluorescent compound fluorescein, which interfered with a standard fluorescent HTS sensor (Fluo-8). In an HTS using a chemical library containing fluorescent compounds, CalfluxCTN accurately identified agonists and antagonists that were missed or miscategorized using Fluo-8. Moreover, we showed that a luciferase substrate that becomes activated only when inside cells generated long-lasting BRET signals in HTS, enabling results to be reliably compared among replicate samples for hours. Thus, the use of a self-luminescent sensor instead of a fluorescent sensor could facilitate the complete screening of chemical libraries in a high-throughput context and enable analysis of autofluorescent samples in many different applications.

Symmetrically substituted dichlorophenes inhibit N-acyl-phosphatidylethanolamine phospholipase D

N-Acyl-phosphatidylethanolamine phospholipase D (NAPE-PLD) (EC 3.1.4.4) catalyzes the final step in the biosynthesis of N-acyl-ethanolamides. Reduced NAPE-PLD expression and activity may contribute to obesity and inflammation, but a lack of effective NAPE-PLD inhibitors has been a major obstacle to elucidating the role of NAPE-PLD and N-acyl-ethanolamide biosynthesis in these processes. The endogenous bile acid lithocholic acid (LCA) inhibits NAPE-PLD activity (with an IC50 of 68 μm), but LCA is also a highly potent ligand for TGR5 (EC50 0.52 μm). Recently, the first selective small-molecule inhibitor of NAPE-PLD, ARN19874, has been reported (having an IC50 of 34 μm). To identify more potent inhibitors of NAPE-PLD, here we used a quenched fluorescent NAPE analog, PED-A1, as a substrate for recombinant mouse Nape-pld to screen a panel of bile acids and a library of experimental compounds (the Spectrum Collection). Muricholic acids and several other bile acids inhibited Nape-pld with potency similar to that of LCA. We identified 14 potent Nape-pld inhibitors in the Spectrum Collection, with the two most potent (IC50 = ∼2 μm) being symmetrically substituted dichlorophenes, i.e. hexachlorophene and bithionol. Structure-activity relationship assays using additional substituted dichlorophenes identified key moieties needed for Nape-pld inhibition. Both hexachlorophene and bithionol exhibited significant selectivity for Nape-pld compared with nontarget lipase activities such as Streptomyces chromofuscus PLD or serum lipase. Both also effectively inhibited NAPE-PLD activity in cultured HEK293 cells. We conclude that symmetrically substituted dichlorophenes potently inhibit NAPE-PLD in cultured cells and have significant selectivity for NAPE-PLD versus other tissue-associated lipases.

Comparative analysis of myometrial and vascular smooth muscle cells to determine optimal cells for use in drug discovery

Novel therapeutic regulators of uterine contractility are needed to manage preterm labor, induce labor and control postpartum hemorrhage. Therefore, we previously developed a high-throughput assay for large-scale screening of small molecular compounds to regulate calcium-mobilization in primary mouse uterine myometrial cells. The goal of this study was to select the optimal myometrial cells for our high-throughput drug discovery assay, as well as determine the similarity or differences of myometrial cells to vascular smooth muscle cells (VSMCs)-the most common off-target of current myometrial therapeutics. Molecular and pharmacological assays were used to compare myometrial cells from four sources: primary cells isolated from term pregnant human and murine myometrium, immortalized pregnant human myometrial (PHM-1) cells and immortalized non-pregnant human myometrial (hTERT-HM) cells. In addition, myometrial cells were compared to vascular SMCs. We found that the transcriptome profiles of hTERT-HM and PHM1 cells were most similar (r = 0.93 and 0.90, respectively) to human primary myometrial cells. Comparative transcriptome profiling of primary human myometrial transcriptome and VSMCs revealed 498 upregulated (p ≤ 0.01, log2FC≥1) genes, of which 142 can serve as uterine-selective druggable targets. In the high-throughput Ca²⁺-assay, PHM1 cells had the most similar response to primary human myometrial cells in OT-induced Ca²⁺-release (E_max = 195% and 143%, EC₅₀ = 30 nM and 120 nM, respectively), while all sources of myometrial cells showed excellent and similar robustness and reproducibility (Z' = 0.52 to 0.77). After testing a panel of 61 compounds, we found that the stimulatory and inhibitory responses of hTERT-HM cells were highly-correlated (r = 0.94 and 0.95, respectively) to human primary cells. Moreover, ten compounds were identified that displayed uterine-selectivity (≥5-fold E_max or EC₅₀ compared to VSMCs). Collectively, this study found that hTERT-HM cells exhibited the most similarity to primary human myometrial cells and, therefore, is an optimal substitute for large-scale screening to identify novel therapeutic regulators of myometrial contractility. Moreover, VSMCs can serve as an important counter-screening tool to assess uterine-selectivity of targets and drugs given the similarity observed in the transcriptome and response to compounds.

A Robust and Scalable High-Throughput Compatible Assay for Screening Amyloid-β-Binding Compounds

A robust fluorescent readout assay using topologically-sensitive dyes improves the screening of novel amyloid-binding molecules. One of the key components that make this assay more realistic is the use of endogenous amyloid obtained from 5XFAD mouse brains. The assay conditions were optimized for high throughput screening operation with Z-prime values >0.6. Using a combination of library of 3,500 compounds including known drugs, natural-derived molecules and random organic molecules, 8 unique molecules were identified as potential amyloid-binding agents.

Discovery, Characterization, and Effects on Renal Fluid and Electrolyte Excretion of the Kir4.1 Potassium Channel Pore Blocker, VU0134992

The inward rectifier potassium (Kir) channel Kir4.1 (KCNJ10) carries out important physiologic roles in epithelial cells of the kidney, astrocytes in the central nervous system, and stria vascularis of the inner ear. Loss-of-function mutations in KCNJ10 lead to EAST/SeSAME syndrome, which is characterized by epilepsy, ataxia, renal salt wasting, and sensorineural deafness. Although genetic approaches have been indispensable for establishing the importance of Kir4.1 in the normal function of these tissues, the availability of pharmacological tools for acutely manipulating the activity of Kir4.1 in genetically normal animals has been lacking. We therefore carried out a high-throughput screen of 76,575 compounds from the Vanderbilt Institute of Chemical Biology library for small-molecule modulators of Kir4.1. The most potent inhibitor identified was 2-(2-bromo-4-isopropylphenoxy)-N-(2,2,6,6-tetramethylpiperidin-4-yl)acetamide (VU0134992). In whole-cell patch-clamp electrophysiology experiments, VU0134992 inhibits Kir4.1 with an IC₅₀ value of 0.97 µM and is 9-fold selective for homomeric Kir4.1 over Kir4.1/5.1 concatemeric channels (IC₅₀ = 9 µM) at -120 mV. In thallium (Tl⁺) flux assays, VU0134992 is greater than 30-fold selective for Kir4.1 over Kir1.1, Kir2.1, and Kir2.2; is weakly active toward Kir2.3, Kir6.2/SUR1, and Kir7.1; and is equally active toward Kir3.1/3.2, Kir3.1/3.4, and Kir4.2. This potency and selectivity profile is superior to Kir4.1 inhibitors amitriptyline, nortriptyline, and fluoxetine. Medicinal chemistry identified components of VU0134992 that are critical for inhibiting Kir4.1. Patch-clamp electrophysiology, molecular modeling, and site-directed mutagenesis identified pore-lining glutamate 158 and isoleucine 159 as critical residues for block of the channel. VU0134992 displayed a large free unbound fraction (f_u) in rat plasma (f_u = 0.213). Consistent with the known role of Kir4.1 in renal function, oral dosing of VU0134992 led to a dose-dependent diuresis, natriuresis, and kaliuresis in rats. Thus, VU0134992 represents the first in vivo active tool compound for probing the therapeutic potential of Kir4.1 as a novel diuretic target for the treatment of hypertension.

Gendered health policies and a women's movement: the Gypsy case

Health concepts depend on socially constructed hygiene practices. Many accounts of "traditional" Gypsy hygiene make gender differentiation primary, implying that traditional health practices reinforce patriarchy and emphasizing the special needs of Gypsy women. This paper argues, however, that the position of women is contested in Romani society. Although prioritizing the more apparent health needs of women and small children appeals to health professionals, this cannot by itself create an effective critique of the health system's response to Gypsy needs. The emergence of a Gypsy women's movement has led to a new critique, and challenge to the victim image of women.

Gonadal dysgenesis in a neonate with 45,X/47,XXX karyotype

A case of X/XXX mosaicism in a neonate with dysgenetic gonads is presented because of the rarity of the X/XXX karyotype and the presence of dysgenetic ovaries and congenital heart anomalies. We suggest that the X/XXX mosaicism may not have a protective effect on the gonads as does X/XX mosaicism in some cases.