The Effect of Salts in Promoting Specific and Competitive Interactions between Zinc Finger Proteins and Metals.

Specific protein-metal interactions (PMIs) fulfill essential functions in cells and organic bodies, and activation of these functions in vivo are mostly modulated by the complex environmental factors, including pH value, small biomolecules, and salts. Specifically, the role of salts in promoting specific PMIs and their competition among various metals has remained untapped mainly due to the difficulty to distinguish nonspecific PMIs from specific PMIs by classic spectroscopic techniques. Herein, we report Hofmeister salts differentially promote the specific PMIs by combining nanoelectrospray ionization mass spectrometry and spectroscopic techniques (fluorescence measurement and circular dichroism). Furthermore, to explore the influence of salts in competitive binding between metalloproteins and various metals, we designed a series of competitive experiments and applied to a well-defined model system, the competitive binding of zinc (II) and arsenic (III) to holo-promyelocytic leukemia protein (PML). These experiments not only provided new insights at the molecular scale as complementary to previous NMR and spectroscopic results, but also deduced the relative binding ability between zinc finger proteins and metals at the molecular scale, which avoids the mass spectrometric titration-based determination of binding constants that is frequently affected and often degraded by variable solution conditions including salt contents. Graphical Abstract ᅟ.

Fecal microbiota transplantation through mid-gut for refractory Crohn's disease: safety, feasibility, and efficacy trial results.

BACKGROUND AND AIM: The gut microbiota plays a pivotal role in the intestinal diseases. Fecal microbiota transplantation (FMT) might be a rescue therapy for refractory inflammatory bowel disease. This study aimed to evaluate the safety, feasibility, and efficacy of FMT through mid-gut for refractory Crohn's disease (CD). METHODS: We established standardized laboratory protocol and clinical work flow for FMT. Only refractory CD patients with Harvey-Bradshaw Index (HBI) score ≥ 7 were enrolled for this study. All included patients were treated with single FMT through mid-gut and assessed during follow-up. RESULTS: Metagenomics analysis showed a high concordance between feces sample and purified fecal microbiota from same donors. Standardized fecal microbiota preparation and clinical flow significantly simplified the practical aspects of FMT. Totally, 30 patients were qualified for the present analysis. The rate of clinical improvement and remission based on clinical activity at the first month was 86.7% (26/30) and 76.7% (23/30), respectively, which was higher than other assessment points within 15-month follow-up. Patients' body weight increased after FMT, and the lipid profile improved as well. FMT also showed a fast and continuous significant effect in relieving the sustaining abdominal pain associated with sustaining CD. CONCLUSION: This is a pilot study with the largest sample of patients with refractory CD who underwent single FMT. The results demonstrated that FMT through mid-gut might be a safe, feasible, and efficient rescue therapy for refractory CD.

High-throughput screening normalized to biological response: application to antiviral drug discovery.

The process of conducting cell-based phenotypic screens can result in data sets from small libraries or portions of large libraries, making accurate hit picking from multiple data sets important for efficient drug discovery. Here, we describe a screen design and data analysis approach that allow for normalization not only between quadrants and plates but also between screens or batches in a robust, quantitative fashion, enabling hit selection from multiple data sets. We independently screened the MicroSource Spectrum and NCI Diversity Set II libraries using a cell-based phenotypic high-throughput screening (HTS) assay that uses an interferon-stimulated response element (ISRE)-driven luciferase-reporter assay to identify interferon (IFN) signal enhancers. Inclusion of a per-plate, per-quadrant IFN dose-response standard curve enabled conversion of ISRE activity to effective IFN concentrations. We identified 45 hits based on a combined z score ≥2.5 from the two libraries, and 25 of 35 available hits were validated in a compound concentration-response assay when tested using fresh compound. The results provide a basis for further analysis of chemical structure in relation to biological function. Together, the results establish an HTS method that can be extended to screening for any class of compounds that influence a quantifiable biological response for which a standard is available.