Oral bioavailability of a noncoding RNA drug, TY1, that acts on macrophages.
Publication Year:
2024
PubMed ID:
38746093
Funding Grants:
Public Summary:
Most RNA-based medicines today have to be given by injection. This study shows a new way to take RNA medicine by mouth. Scientists created a special package using natural materials like milk protein and chitosan to protect a tiny synthetic RNA called TY1, which targets immune cells involved in tissue damage.
When given orally to mice and rats, this RNA medicine was safe and helped protect the heart after a heart attack and reduced lung inflammation. Instead of entering the bloodstream, the RNA was taken up by immune cells in the gut. This might explain why some RNA drugs work well when taken by mouth, while others don’t.
This discovery could make it easier to develop RNA medicines that you can swallow, using the gut’s immune system to deliver the treatment.
Scientific Abstract:
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.