Lecture Summaries

The summaries below provide an overview of what was covered in each session of this course. Detailed lecture notes are not available for this course.

1 Welcome and Overview Instructors and students will introduce themselves. We will discuss the course objectives, determine a suitable meeting time, and review the syllabus.
2 Introduction to RNAi We will introduce the basic properties of RNA interference by discussing a seminal study in the field. We will also explore how gene silencing can spread systemically between tissues in an organism.
3 Hints of the Future: The Discovery of miRNAs Before the discovery of RNAi, there were examples in the literature of small RNAs, specifically microRNAs, regulating gene expression post-transcriptionally. We will discuss the earliest example of a miRNA and consider the general mechanism of miRNA target recognition.
4 Mechanisms: Dicing and Slicing Small RNAs require proteins to carry out their important functions. We will discuss a few of the key catalytic enzymes in the RNAi pathway.
5 How miRNAs Relate to siRNAs Most of the literature draws a clear distinction between endogenous miRNAs and synthetic siRNAs, but how different are they?
6 RNAi in the Lab I: shRNA, siRNA, and miRNA Mimics In addition to playing important biological functions, the RNAi pathway can be exploited in the lab for experimental analysis of gene function. We will discuss the two main methods of gene knockdown by RNAi: the use of synthetic siRNAs and the use of expression constructs that supply cells with siRNA precursors in vivo.
7 RNAi in the Lab II: Screening for Hits Historically, genetic screens have been restricted to organisms that can be mutated easily, one gene at a time, and analyzed individually for various phenotypes. Such organisms include baker's yeast (S. cerevisiaie), the fruit fly (D. melanogaster), and the worm (C. elegans). Now, RNAi provides the tools that allow thorough and systematic genetic screens using mammalian cell lines, thereby yielding novel drug targets in systems directly relevant to human disease.
8 Company Visit: Alnylam A first-hand look at a player in the newly-emerging private sector pursuing RNAi therapeutics.
9 RNAi Therapeutics I: Selecting Targets The "off-target" effects of a drug cause unwanted side effects that can, if severe enough, limit the therapeutic utility of the drug. Such effects are also possible in the realm of RNAi, often as a consequence of the biological mechanism of action of these molecules.
10 RNAi Therapeutics II: The Importance of Chemistry The needs of a cell in vivo and the needs of a physician in the clinic are very different. We will discuss how we can improve on the chemical properties of siRNAs to make them more therapeutically useful.
11 RNAi Therapeutics III: Efficacy in Animals If RNAi is to be used to treat patients, our studies need to go beyond in vitro cell-based assays. We will discuss the efficacy of siRNAs in mouse models.
12 RNAi Therapeutics IV: Safety First To "do no harm" is the credo of the physician. By treating organisms with synthetic siRNAs, we risk competing with normal endogenous small RNAs and possibly causing toxicity. We will discuss the various methods of gene silencing in organisms and the toxicity of each approach.
13 RNAi Therapeutics V: Delivery, Delivery, Delivery A drug is useful only if it reaches its target. Small molecules, by virtue of their size and chemical properties, can distribute in a patient easily. In contrast, siRNAs are larger and highly charged, posing significant and unique challenges to delivery of these agents to the relevant tissue. We will discuss two strategies to overcome these obstacles.
14 Oral Presentations If time allows, we will also review and discuss the course.