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microRNA therapeutics

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A presentation on microRNA and its therapeutics

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microRNA therapeutics

  1. 1. MicroRNA therapeutics Shravan Morla 2011A5TS698H Srividya Myneni 2011A5TS096H
  2. 2. Contents • Introduction of microRNA • Discovery of microRNA • Micro RNA biogenesis • Mechanism of action of microRNA
  3. 3. microRNA (miRNA) • miRNAs are non-coding RNAs found only in eukaryotes • Single stranded and small in size (˷22 nt long) • Comprise one of the more classes of gene regulatory molecules • Play important regulatory roles in animals and plants by targeting mRNAs for cleavage or translational repression
  4. 4. Discovery of miRNA • The first miRNA was discovered in 1993 during a study of the lin-4 gene, which was known to control the timing of C. elegans larval development by repressing the lin-14 gene. • When they isolated the lin-4 gene, they found that instead of producing an mRNA encoding a protein, it produced short noncoding RNAs, one of which was a ~22-nucleotide RNA that contained sequences partially complementary to multiple sequences in the 3' UTR of the lin-14 mRNA. • This complementarity was proposed to inhibit the translation of the lin-14 mRNA into the LIN-14 protein • At the time, the lin-4 small RNA was thought to be a nematode idiosyncrasy.
  5. 5. • Only in 2000 was a second small RNA characterized: let-7 RNA, which represses lin-41 to promote a later developmental transition in C. elegans. • The let-7 RNA was soon found to be conserved in many species, leading to the suggestion that let-7 RNA and additional "small temporal RNAs" might regulate the timing of development in diverse animals, including humans. • A year later, the lin-4 and let-7 RNAs were found to be part of a very large class of small RNAs present in C. elegans, Drosophila and human cells. • The many newly discovered RNAs of this class resembled the lin-4 and let-7 RNAs, except their expression patterns were usually inconsistent with a role in regulating the timing of development, which suggested that most might function in other types of regulatory pathways. At this point, researchers started using the term “microRNA” to refer to this class of small regulatory RNAs.
  6. 6. miRNA Biogenesis
  7. 7. Transcription RNA Polymerase II Sequence complementarity Pri miRNA Drosha and DGCR8 complex
  8. 8. Exportin V Pre-miRNA moves to the cytoplasm Dicer miRNA:miRNA* duplex RISC miRNA
  9. 9. miRNA mechanism of action
  10. 10. Target mRNAmiRNA Argonaute
  11. 11. Fig: Biogenesis and MOA of microRNA. Source: Eva van Rooij, Sakari Kauppinen. Development of microRNA therapeutics is coming of age. EMBO Mol Medicine. 2014 Jun 16
  12. 12. miRNA therapeutics
  13. 13. Mechanism of miRNA
  14. 14. Micro RNA therapeutics • AntimiRs • miRNA Mimics
  15. 15. Micro RNA therapeutics o Sponges o Target Occupiers o Erasers
  16. 16. Delivery of miRNA
  17. 17. PHYSICAL APPROACHES FOR miRNA DELIVERY • 2′-deoxyoligonucleotides • 2′-OMe–modified oligoribonucleotides (2′- OMes) • cholesterol moiety– conjugated 2′-OMes • LNA(locked nucleic acid) • oligonucleotides containing 2′-MOE, 2′-flouro (2′-F), and phosphorothioate backbone modifications. • peptide nucleic acids.
  18. 18. NONVIRAL DELIVERY • Gene gun system • Electro-transfer(cyanine 5′–labeled molecules) • Exosome like nanovesicles • Nanocapsules, Nanoparticles, and Nanospheres • Polyethylenimines
  19. 19. Gene gun Electro-transfer of antimiR’s
  20. 20. Chemical modifications • Cell penetrating peptide(CPP) conjugation (penetratin, transportan, tetra-lysine, arginine oligomers) • Peptide Nucleic Acids (sugar-phosphate backbone is replaced by N-(2- aminoethyl) glycine units)
  21. 21. VIRAL VECTOR-BASED miRNA DELIVERY AND EXPRESSION • Retro viral vectors • Lenti viral vectors • Adenoviral vectors
  22. 22. AntimiR therepeutics
  23. 23. miRNA’s in clinical studies • MiR-122 (Hepatitis C Virus) • MiR-155 (Inflammatory Disease) • MiR-21 (Fibrosis) • MiR-92a( Neoangiogenesis) • MiR-33 (Metabolic Disease) • MiR-451 (Myeloproliferative Disease) • MiR-15 (Cardiac Regeneration and Injury)
  24. 24. MicroRNA expression in human cancer • oncogenes or oncosuppressor genes o Presence of miR‐15a and miR‐16‐1 instead of tumor supressor gene in deleted chromosome in CLL o Increased expression of the microRNA Tumor supressor gene is not all expressed because of inhibition by miRNA. o cell migration and metastasis
  25. 25. Role of microRNAs in cancer
  26. 26. MiR-122 • Regulator of fatty-acid metabolism • MiR-122 - hepatocellular carcinoma • Regulation of hepatitis C virus replication MiR-155 • Hematopoiesis & Immune system • Cardiovascular diseases • Lymphocyte malignancies • Inflammation
  27. 27. MiR-21 • First microRNA as an oncomir • MiR-21- failing murine and human heart • chemically modified and cholesterol-conjugated miRNA inhibitors (antagomirs) was shown to inhibit interstitial fibrosis and improve cardiac function MiR-92a • miR-92a in acute myeloid leukaemia and acute lymphoblastic leukaemia • miR-92 hepatocellular Cancer • MiR-92a in neoangiogenesis
  28. 28. MiR-33 • Lipid metabolism o Cholesterol and HDL generation o Fatty acid degradation o MiR-33 & miR-122 in metabolic disorders and cardiovascular diseas MiR-451 • miR-451- hematocrit(erythroid differentiation defect) - ineffective erythropoiesis
  29. 29. Challenges for Micro RNA therapy • Numerous molecular targets for miRNA • Degradation by nucleases and phosphodiesterases • Optimal chemistry and delivery systems have to be developed.
  30. 30. References • E. van Rooij, A.L. Purcell, A.A. Levin, Developing microRNA therapeutics, Circulation research, 110 (2012) 496-507. • E. van Rooij, W.S. Marshall, E.N. Olson, Toward MicroRNA–Based Therapeutics for Heart Disease The Sense in Antisense, Circulation research, 103 (2008) 919- 928. • M.S. Ebert, J.R. Neilson, P.A. Sharp, MicroRNA sponges: competitive inhibitors of small RNAs in mammalian cells, Nature methods, 4 (2007) 721-726.
  31. 31. Questions? THANK YOU!