| Sepsis and traumatic injury can result in over-activation of the inflammatory cascade, acute respiratory distress syndrome (ARDS), and ultimately death. The cytokines interleukin-1beta (IL-1beta) and tumor necrosis factor (TNF) are increased in the pulmonary edema fluid of patients with ARDS. Here, we study the therapeutic effects of blocking either one of the major cytokines, TNF, or a kinase in the IL-1beta pathway, interleukin 1 receptor associated kinase-1 (IRAK1), in macrophages. Production of these proteins can be blocked by the delivery of small interfering RNA (siRNA) or antisense oligodeoxynucleotides (ASODN). However, the clinical success of these nucleic acid-based biotherapeutics faces several barriers. Among these is efficient, nontoxic cellular delivery. pH-sensitive, membrane-disruptive polymers have been developed in our laboratory to enhance the delivery of biotherapeutics into the cytoplasm of cells. Biotherapeutics are normally taken up through endocytosis, resulting in lysosomal degradation. The major advantage of our polymeric carriers is that they are hydrophilic and not membrane interactive at physiological pH, but become hydrophobic and membrane destabilizing at the low pH of the endosome such that a therapeutic is delivered from the endosome into the cytoplasm of a cell. In these studies, several pH-responsive polymer carriers are studied for the delivery of nucleic acid therapeutics. Included in this dissertation is the successful delivery of: plasmid DNA via a lipopolyplex, an anti-inflammatory antisense oligonucleotide with a pH-responsive polymer, and a siRNA therapeutic for efficient expression knockdown using a reversible, pH-responsive polymeric system. |
