Delivering 27mer DsiRNAs to Mice DRGs

I have been a proponent of using 27mer DsiRNAs (Dicer Substrate Small Interfering RNAs) with our i-Fect kits to deliver siRNA to the CNS for gene expression analysis. The potency of this platform was highlighted in my profile of Dr. Mark Behlke.

It was further confirmed  in Studies conducted by Dr. Philippe Serrat and his team at University of Sherbrooke.

Louis Doré-Savard, Geneviève Roussy, Marc-André Dansereau, Michael A Collingwood, Kim A Lennox, Scott D Rose, Nicolas Beaudet, Mark A Behlke and Philippe Sarret. Central Delivery of Dicer-substrate siRNA: A Direct Application for Pain Research. Molecular Therapy (2008); Jul;16(7):1331-9. Epub 2008 Jun 3 doi:10.1038/mt.2008.98.

Using ultra low dose of DsiRNAs complexed with Neuromics’  i-Fect , they were able to successfully reduce NTS2 gene expression by up to 86% in rat lumbar Dorsal Root Ganglia after only two intrathecal injections. This was confirmed by Western Blot and qPCR analysis.

We now have further confirmation of the capabilities of this delivery platform in a just released publication by Dr. Jeffrey Mogil and team:

Michael L. LaCroix-Fralish, Gary Mo, Shad B. Smith, Susana G. Sotocinal, Jennifer Ritchie, Jean-Sebastien Austin, Kara Melmed, Ara Schorscher-Petcu, Audrey C. Laferriere, Tae Hoon Lee, Dmitry Romanovsky, Guochun Liao, Mark A. Behlke, David J. Clark, Gary Peltz, Philippe Séguéla, Maxim Dobretsov and Jeffrey S. Mogil. The β3 subunit of the Na+,K+-ATPase mediates variable nociceptive sensitivity in the formalin test. doi:10.1016/j.pain.2009.04.028.

IT Delivery of siRNA in vivo supplement

Knockdown of rSNSR1 in vivo

I have featured successes with delivering siRNA in vivo in this blog. These included stories on Dr. Philipe Serrat and his team at the University of Sherbrooke and Dr. Mark Behlke’s work at Integrated DNA and Dicerna.

I am pleased to report the parade of success with use our i-FectTM in vivo grows. 

Here’s the most recent study:

Christian Ndong, Amynah Pradhan, Carole Puma, Jean-Pierre Morello, Cyrla Hoffert, Thierry Groblewski , Dajan O’Donnell, Jennifer M.A. Laird. Role of rat sensory neuron-specific receptor (rSNSR1) in inflammatory pain: Contribution of TRPV1 to SNSR signaling in the pain pathway. PAIN 143 (2009) 130–137.
…For experiments in which siRNA was delivered by bolus injections, 10 ul of siRNA or vehicle was injected directly into the intrathecal catheter once daily for 4 days. In this case, siRNAs were prepared immediately prior to administration by mixing the RNA solution (200 uM in annealing buffer) with the transfection reagent i-FectTM (Neuromics) at a ratio of 1:4 (w:v) for a final siRNA/ lipid complex concentration of 2 ug/10 ul…

Related Data:

Images: in vivo characterization of knockdown produced by rSNSR1 siRNA. (A) A dose-dependent decrease in rSNSR1 mRNA levels measured in lumbar L3/L4/L5 DRGs was
observed when rSNSR1 siRNA (n = 7–14/group) or MM siRNA (n = 6/group) was delivered by four daily bolus injections. *p < 0.05; **p < 0.01; ***p < 0.001 as determined by oneway analysis of variance followed by sequential testing. (B) rSNSR1 immunoreactivity in dorsal horn of the spinal cord was visibly reduced in rSNSR1 siRNA-treated animals (5 lg/day, left panel). Immunoreactivity with neuron-specific isolectin B4 (IB4; right panel) did not change between treatment groups, showing the integrity of each dorsal horn analyzed (n = 6/group). (C) A semi-quantitative score of rSNSR1 immunoreactivity showed that siRNA treatment greatly decreased rSNSR1 protein levels compared to MM and control groups. A blinded observer scored 9–12 individual sections taken from a 1 cm segment of the spinal cord.

Dr. Behlke’s 27mer DsiRNA Story Coming Soon

Learn the News Behind the News on 27mer DsiRNA. Includes the story of the how the potentcy of 27mer siRNA was discovered and exiting developments regarding the understanding of the role of the Dicer Complex and RISC. Also featured will be advances in 27mer oligo design and how the technology is being used in basic research and drug discovery.

Here’s a publication highlighting the roots of the story:

Dong Ho Kim, Mark Behlke, Scott Rose, Mi-Sook Chang, Sangdun Choi & John Rossi. Synthetic dsRNA Substrates Enhance RNAi Potency and Efficacy Nature Biotechnology. Published online 26 December 2004;doi10.1038/nbt1051.