Scientists Demonstrate an RNAi Approach for In Vivo Therapeutic Silencing of MicroRNAs
News Oct 31, 2005
Alnylam Pharmaceuticals, Inc. has announced the publication of an approach to regulate gene expression through the silencing of microRNAs.
miRNAs have been shown to regulate a large number of genes in the human genome through the RNAi pathway. Many of these miRNAs are believed to be involved in disease processes.
In the paper published in Nature, scientists from The Rockefeller University and Alnylam describe the rational design of a potential new class of chemically modified RNA-based drugs, called ‘antagomirs’ that specifically silence miRNAs across multiple tissue types following therapeutically relevant administration in animals.
“We believe this research creates the opportunity to design antagomirs that target miRNAs in the context of human diseases, such as cancer and viral infection,” said Markus Stoffel, M.D., Ph.D., Robert and Harriet Heilbrunn Professor of The Rockefeller University's Laboratory of Metabolic Diseases.
“miRNAs are critical for the control of gene expression in all living cells, and appear to play an important role in both normal and disease physiology. There are over 250 genes that encode for miRNAs in the human genome and these appear to regulate as much as one-third of all gene expression”
“Our discovery of antagomirs represents the first-ever demonstration of a pharmacologic strategy to silence miRNAs. These antagomirs have remarkable properties including high potency, high specificity, broad bioavailability, and long-lasting effects, and we believe this may have profound implications for the treatment of many human diseases.”
In the Nature paper, antagomirs that target miRNA-16, miRNA-122, miRNA-192, and miRNA-194 demonstrated specific in vivo silencing of the target miRNA in tissues including liver, lung, kidney, heart, and bone marrow.
This silencing was shown to be sustained for over 20 days following a single treatment course. Bioinformatic analyses of gene expression data from antagomir-treated animals revealed a greater degree of gene regulation by miRNAs than previously estimated.
Further, efficient silencing of miRNA-122, a liver-specific miRNA recently shown to be required for hepatitis C infection, was achieved without any evidence of adverse effects.
This silencing of miRNA-122 was associated with the regulation of a discrete set of genes involved in liver metabolism.
“The opportunity to target miRNAs involved in human disease with antagomirs greatly extends Alnylam's platform for harnessing RNAi for therapeutic applications,” said John Maraganore, Ph.D., President and Chief Executive Officer of Alnylam.
“This ground-breaking discovery is yet further demonstration of Alnylam's clear scientific leadership in translating RNAi biology into a robust product engine for innovative medicines.”
“We are hopeful that antagomirs will represent an important therapeutic strategy for Alnylam and its partners in the years to come, complementing our near-term focus on development and commercialization of direct RNAi therapeutics targeted toward pulmonary, CNS, and ocular diseases.”
Alnylam and The Rockefeller University have a collaboration agreement for research in the field of RNAi. Alnylam has taken an exclusive license to all of The Rockefeller University's interest in antagomir technology.