Tyrosine-Mutant AAV8 Vector Mediated Efficient and Safe Gene Transfer of Pigment Epithelium-Derived Factor to Mouse Lungs.

BACKGROUND/AIMS: Recombinant adeno-associated viruses (rAAV) are an important tool for lung targeted gene therapy. Substitution of tyrosine with phenylalanine residues (Y-F) in the capsid have been shown to protect the AAV vector from ubiquitin/proteasome degradation, increasing transduction efficiency. We tested the mutant Y733F-AAV8 vector for mucus diffusion, as well as the safety and efficacy of pigment epithelium-derived factor (PEDF) gene transfer to the lung. METHODS: For this purpose, Y733F-AAV8-PEDF (1010 viral genome) was administered intratracheally to C57BL/6 mice. Lung mechanics, morphometry, and inflammation were evaluated 7, 14, 21, and 28 days after injection. RESULTS: The tyrosine-mutant AAV8 vector was efficient at penetrating mucus in ex vivo assays and at transferring the gene to lung cells after in vivo instillation. Increased levels of transgene mRNA were observed 28 days after vector administration. Overexpression of PEDF did not affect in vivo lung parameters. CONCLUSION: These findings provide a basis for further development of Y733F-AAV8-based gene therapies for safe and effective delivery of PEDF, which has anti-angiogenic, anti-inflammatory and anti-fibrotic activities and might be a promising therapy for lung inflammatory disorders.

Inhaled gene therapy of preclinical muco-obstructive lung diseases by nanoparticles capable of breaching the airway mucus barrier.

INTRODUCTION: Inhaled gene therapy of muco-obstructive lung diseases requires a strategy to achieve therapeutically relevant gene transfer to airway epithelium covered by particularly dehydrated and condensed mucus gel layer. Here, we introduce a synthetic DNA-loaded mucus-penetrating particle (DNA-MPP) capable of providing safe, widespread and robust transgene expression in in vivo and in vitro models of muco-obstructive lung diseases. METHODS: We investigated the ability of DNA-MPP to mediate reporter and/or therapeutic transgene expression in lung airways of a transgenic mouse model of muco-obstructive lung diseases (ie, Scnn1b-Tg) and in air-liquid interface cultures of primary human bronchial epithelial cells harvested from an individual with cystic fibrosis. A plasmid designed to silence epithelial sodium channel (ENaC) hyperactivity, which causes airway surface dehydration and mucus stasis, was intratracheally administered via DNA-MPP to evaluate therapeutic effects in vivo with or without pretreatment with hypertonic saline, a clinically used mucus-rehydrating agent. RESULTS: DNA-MPP exhibited marked greater reporter transgene expression compared with a mucus-impermeable formulation in in vivo and in vitro models of muco-obstructive lung diseases. DNA-MPP carrying ENaC-silencing plasmids provided efficient downregulation of ENaC and reduction of mucus burden in the lungs of Scnn1b-Tg mice, and synergistic impacts on both gene transfer efficacy and therapeutic effects were achieved when DNA-MPP was adjuvanted with hypertonic saline. DISCUSSION: DNA-MPP constitutes one of the rare gene delivery systems providing therapeutically meaningful gene transfer efficacy in highly relevant in vivo and in vitro models of muco-obstructive lung diseases due to its unique ability to efficiently penetrate airway mucus.

Listeria, Then and Now: A Call to Reevaluate Patient Teaching Based on Analysis of US Federal Databases, 1998-2016.

INTRODUCTION: Listeria monocytogenes is a foodborne pathogen capable of crossing the placental-fetal barrier; infection with the bacterium causes listeriosis. An exposed fetus may suffer blindness, neurological damage including meningitis, or even death. The adverse consequences of listeriosis place the infection on the federally reportable disease list. Primary prevention relies on women avoiding 6 categories of foods most likely to be contaminated with L monocytogenes, as indicated in guidelines developed by the Centers for Disease Control and Prevention (CDC), adapted by the American College of Obstetricians and Gynecologists (ACOG) in 2014, and reaffirmed without changes by ACOG in 2016. This report contains a critical evaluation of United States listeriosis prevention guidelines. METHODS: Between 1998 and 2016, there were 876 identified listeriosis events documented in the illness and recall databases maintained by the CDC, Food and Drug Administration (FDA), and United States Department of Agriculture - Food Safety and Inspection Service (USDA-FSIS). Each contaminated food was manually compared to the existing listeriosis avoidance guidelines, placing each event within or outside the guidelines. Trends were analyzed over time. RESULTS: Database analysis demonstrates that prior to the year 2000, abiding by the current guidelines would have prevented all reported listeriosis cases. However, in 2015 and 2016, only 5% of confirmed L monocytogenes infections originated from the 6 food groups listed in the CDC and ACOG guidelines. Similar trends emerged for food processing plant recalls (USDA-FSIS database) and grocery store recalls (FDA database). The total number of listeriosis illnesses in the United States doubled from 2007 to 2014. DISCUSSION: A gradual shift in detection of L monocytogenes contamination in ready-to-eat meals, frozen foods, and ready-to-eat salads has occurred. Another emerging culprit is pasteurized dairy products. Revision of listeriosis avoidance guidelines by a consensus-seeking, multidisciplinary task force, is needed.