Discovery of Surfactant-Like Peptides from a Phage-Displayed Peptide Library

Peptides with specific affinities for various materials have been identified in the past three decades and utilized in materials science and engineering. A peptide’s capability to specifically interact with materials is not naturally derived but screened from a biologically constructed peptide library displayed on phages or cells. To date, due to limitations in the screening procedure, the function of screened peptides has been primarily limited to the affinity for target materials. Herein, we demonstrated the screening of surfactant-like peptides from a phage-displayed peptide library. A screened phage clone displaying a peptide showed high activity for accumulating at emulsion surfaces with certain assembled structures, resulting in stable emulsions. The surface tension for the solution of the chemically synthesized peptide decreased with increasing peptide concentration, demonstrating certain surface activity, which corresponded to the ability to decrease the surface tension of liquids (e.g., water), owing to the accumulation of molecules at the air–liquid or liquid–liquid interface. Peptides with a randomized sequence did not lower the surface tension, indicating the essential role of amino acid sequences in surface activity. Our strategy for identifying novel functional peptides from a phage-displayed peptide library can be used to expand the applicability of peptidyl materials and biosurfactants

The Cancer Stem Cell Marker CD133 Interacts with Plakoglobin and Controls Desmoglein-2 Protein Levels

<div><p>The pentaspan membrane glycoprotein CD133 (also known as prominin-1) has been widely used as a marker for both cancer and normal stem cells. However, the function of CD133 has not been elucidated. Here we describe a cancer stem cell line established from clear cell carcinoma of the ovary (CCC) and show that CD133 interacts with plakoglobin (also known as γ-catenin), a desmosomal linker protein. We further demonstrate that knockdown of CD133 by RNA interference (RNAi) results in the downregulation of desmoglein-2, a desmosomal cadherin, and abrogates cell-cell adhesion and tumorigenicity of CCC stem cells. We speculate that CD133 may be a promising target for cancer chemotherapy.</p> </div

CD133 controls cell-cell adhesion and is required for tumorigenicity of CCC stem cells.

<p>(A) CCC stem cells were infected with a lentivirus expressing an shRNA targeting CD133. Cells were subjected to mechanical stress by pipetting in PBS containing 1 mM CaCl₂ and 0.5 mM MgCl₂. Representative images are shown (upper). The bar graph represents the ratio of cell number/cluster number (lower). Error bars represent the s.d. (<i>n</i> = 3). <i>p</i> = 0.011 with comparison to control shRNA by t test. (B) CCC stem cells were treated as described in (A). Cell lysates were subjected to immunoblotting with antibodies to the indicated proteins. (C) CCC stem cells were treated as described in (A). Cells were immunostained with antibodies to the indicated proteins (red). TO-PRO-3 iodide was used for nuclear DNA staining (blue). Scale bars represent 20 µm. (D) CCC stem cells were treated as described in (A). Cells were subcutaneously transplanted into immunocompromised mice (<i>n</i> = 3). Eleven months after transplantation, mice (upper) and tumors (middle) were photographed. The bar graph represents tumor weight (lower). Error bars represent the s.d. (<i>n</i> = 3). <i>p</i> = 0.007 with comparison to control shRNA by t test.</p

Analysis of Outcomes in Ischemic vs Nonischemic Cardiomyopathy in Patients With Atrial Fibrillation A Report From the GARFIELD-AF Registry

IMPORTANCE Congestive heart failure (CHF) is commonly associated with nonvalvular atrial fibrillation (AF), and their combination may affect treatment strategies and outcomes