Targeted mRNA Therapy for Ornithine Transcarbamylase Deficiency.

We describe a novel, two-nanoparticle mRNA delivery system and show that it is highly effective as a means of intracellular enzyme replacement therapy (i-ERT) using a murine model of ornithine transcarbamylase deficiency (OTCD). Our Hybrid mRNA Technology delivery system (HMT) comprises an inert lipid nanoparticle that protects the mRNA from nucleases in the blood as it distributes to the liver and a polymer micelle that targets hepatocytes and triggers endosomal release of mRNA. This results in high-level synthesis of the desired protein specifically in the liver. HMT delivery of human OTC mRNA normalizes plasma ammonia and urinary orotic acid levels, and leads to a prolonged survival benefit in the murine OTCD model. HMT represents a unique, non-viral mRNA delivery method that allows multi-dose, systemic administration for treatment of single-gene inherited metabolic diseases.

Phage display screening of epithelial cell monolayers treated with EGTA: identification of peptide FDFWITP that modulates tight junction activity.

Phage display was used to screen for peptides that modulate the activity of epithelial cell tight junctions. Panning with a phage library that displays random 7-mers was performed using monolayers of human bronchial epithelial cells (16HBE14o(-)) treated with a calcium chelator, ethylene glycol-bis(2-aminoethylether)- N, N, N', N'-tetraacetic acid (EGTA), to increase accessibility to the junctional complex/paracellular space, followed by subtractive panning. A novel peptide, FDFWITP, identified as a potential tight junction modulator, was synthesized in linear and cyclic forms with lysine residues added to improve solubility. The cyclic form of the peptide reduced transepithelial electrical resistance (TER) in a concentration-dependent manner (80% reduction at 100 microM and 95% reduction at 500 microM) and was reversible within 2 h; the linear form only affected TER at the highest concentration. Interestingly, the constrained peptide did not increase permeation of the model small molecule, fluorescein. The highly selective activity of FDFWITP supports the hypothesis that ions and small molecules may be transported paracellularly across tight junctions by separate pathways.

Stromelysin-1 and mesothelin are differentially regulated by Wnt-5a and Wnt-1 in C57mg mouse mammary epithelial cells.

BACKGROUND: The Wnt signal transduction pathway is important in a wide variety of developmental processes as well as in the genesis of human cancer. Vertebrate Wnt pathways can be functionally separated into two classes, the canonical Wnt/beta-catenin pathway and the non-canonical Wnt/Ca2+ pathway. Supporting differences in Wnt signaling, gain of function of Wnt-1 in C57mg mouse mammary epithelial cells leads to their morphological transformation while loss of function of Wnt-5a leads to the same transformation. Many downstream target genes of the Wnt/beta-catenin pathway have been identified. In contrast, little is known about the Wnt/Ca2+ pathway and whether it regulates gene expression. RESULTS: To test the hypothesis that a specific cell line can respond to distinct Wnts with different patterns of gene expression, we over-expressed Wnt-5a and Rfz-2 in C57mg mammary epithelial cells and compared this cell line to C57mg cells over-expressing Wnt-1. These Wnts were chosen since previous studies suggest that C57mg cells respond differently to these Wnts, and since these Wnts can activate different signaling pathways in other systems. Using DNA microarray analysis, we identified several genes that are regulated by Wnt-5a and Rfz-2 as well as by Wnt-1. We then focused on two genes previously linked to various cancers, mesothelin and stromelysin-1, which are respectively up-regulated by Wnt-1 and Wnt-5a in C57mg cells. CONCLUSION: Different Wnts have distinct effects on gene expression in a single cell line.