Novel farnesylthiosalicylate (FTS)-eluting composite structures

Innate inflammation induced by the 8-oxoguanine DNA glycosylase-1-KRAS-NF-κB pathway

8-Oxoguanine-DNA glycosylase-1 (OGG1) is the primary enzyme for repairing 7,8-dihydro-8-oxoguanine (8-oxoG) via the DNA base excision repair pathway (OGG1-BER). Accumulation of 8-oxoG in the genomic DNA leads to genetic instability and carcinogenesis and is thought to contribute to the worsening of various inflammatory and disease processes. However, the disease mechanism is unknown. In this study, we proposed that the mechanistic link between OGG1-BER and proinflammatory gene expression is OGG1's guanine nucleotide exchange factor activity, acquired after interaction with the 8-oxoG base and consequent activation of the small GTPase RAS. To test this hypothesis, we used BALB/c mice expressing or deficient in OGG1 in their airway epithelium and various molecular biological approaches, including active RAS pulldown, reporter and Comet assays, small interfering RNA-mediated depletion of gene expression, quantitative RT-PCR, and immunoblotting. We report that the OGG1-initiated repair of oxidatively damaged DNA is a prerequisite for GDP → GTP exchange, KRAS-GTP-driven signaling via MAP kinases and PI3 kinases and mitogen-stress-related kinase-1 for NF-κB activation, proinflammatory chemokine/cytokine expression, and inflammatory cell recruitment to the airways. Mice deficient in OGG1-BER showed significantly decreased immune responses, whereas a lack of other Nei-like DNA glycosylases (i.e., NEIL1 and NEIL2) had no significant effect. These data unveil a previously unidentified role of OGG1-driven DNA BER in the generation of endogenous signals for inflammation in the innate signaling pathway.

Highly porous drug-eluting structures: from wound dressings to stents and scaffolds for tissue regeneration

For many biomedical applications, there is need for porous implant materials. The current article focuses on a method for preparation of drug-eluting porous structures for various biomedical applications, based on freeze drying of inverted emulsions. This fabrication process enables the incorporation of any drug, to obtain an "active implant" that releases drugs to the surrounding tissue in a controlled desired manner. Examples for porous implants based on this technique are antibiotic-eluting mesh/matrix structures used for wound healing applications, antiproliferative drug-eluting composite fibers for stent applications and local cancer treatment, and protein-eluting films for tissue regeneration applications. In the current review we focus on these systems. We show that the release profiles of both types of drugs, water-soluble and water-insoluble, are affected by the emulsion's formulation parameters. The former's release profile is affected mainly through the emulsion stability and the resulting porous microstructure, whereas the latter's release mechanism occurs via water uptake and degradation of the host polymer. Hence, appropriate selection of the formulation parameters enables to obtain desired controllable release profile of any bioactive agent, water-soluble or water-insoluble, and also fit its physical properties to the application.