Oral bioavailability of a noncoding RNA drug, TY1, that acts on macrophages

All approved RNA therapeutics require parenteral delivery. Here we demonstrate an orally bioavailable formulation wherein synthetic noncoding (nc) RNA, packaged into lipid nanoparticles, is loaded into casein-chitosan (C2) micelles. We used the C2 formulation to deliver TY1, a 24-nucleotide synthetic ncRNA which targets the DNA damage response pathway in macrophages. C2-formulated TY1 (TY1 C2 ) efficiently packages and protects TY1 against degradative enzymes. In healthy mice, oral TY1 C2 was well-tolerated and nontoxic. Oral TY1 C2 exhibited disease-modifying bioactivity in 2 models of tissue injury: 1) rat myocardial infarction, where a single oral dose of TY1 C2 was cardioprotective, on par with intravenously-delivered TY1; and 2) mouse acute lung injury, where a single dose of TY1 C2 attenuated pulmonary inflammation. Mechanistic dissection revealed that TY1 C2 is not absorbed into the systemic circulation but is, instead, taken up by intestinal macrophages, namely those of the lamina propria and Peyer’s patches. This route of absorption may rationalize why an antisense oligonucleotide against Factor VII, which acts on hepatocytes, is not effective when administered in the C2 formulation. Thus, some (but not all) ncRNA drugs are bioavailable when delivered by mouth. Oral RNA delivery and uptake, relying on uptake via the gastrointestinal immune system, has broad-ranging therapeutic implications. Graphical Abstract Oral TY1 C2 is taken up in the small intestine mainly by macrophages of the lamina propria and the Peyer’s patches. Macrophages that have taken up oral TY1 C2 mediate disease-modifying bioactivity in 2 animal models of acute tissue injury. The blue + denotes the as-yet-uncertain mechanisms/mediators linking TY1 gut uptake to the drug’s systemic therapeutic benefits.