Transfecting Sympathetic Neurons

GDNF and Ret are important to the growth, maintenance and survival of Neurons. The GDNF ligands act via activation of Ret. Every step towards understanding the intricacies of this pathway, brings researchers closer towards unlocking the code for Neurodegenerative Disease therapies.

siRNA is an important tool for studying the Neurotrophic pathways as researchers can use it to modulate the expression of related receptors. The tricky part is getting sufficient siRNA into neurons to do the appropriate studies of how modulating targeted genes results in changes in protein expression.

Here Drs. Cynthia Tsui and Brian Pierchala have published results from there studies of C2AP and Cbl-3/Cbl-c and Ret Transduction. One of the keys to this study was using siRNA to silence CD2AP and Cbl-3 expression. By turning these off they were able to identify a critical checkpoint in the Ret pathway.

Cynthia C. Tsui and Brian A. Pierchala CD2AP and Cbl-3/Cbl-c Constitute a Critical Checkpoint in the Regulation of Ret Signal TransductionJ. Neurosci., Aug 2008; 28: 8789 - 8800 ; doi:10.1523/JNEUROSCI.2738-08.2008.

...Control, CD2AP, and Cbl-3 siRNAs (Applied Biosystems/Ambion) were transfected into 4 DIV sympathetic neurons using the i-Fect ™ reagent according to the manufacturer’s instructions (Neuromics). Transfection efficiency was determined by the cotransfection of a fluorescently labeled nontargeting, control siRNA (siGLO RISC-free siRNA; Dharmacon RNA Technologies). Immunoblotting of the targeted proteins determined that the maximal knockdown of protein expression was observed 72 h after siRNA transfection. Greater than 90% of SCG neurons were transfected, as ascertained by the level of intracellular fluorescence of the siGLO siRNA.

Down Regulating the Smad and Neuro-regeneration

The inventors down regulated Smad 2/3 (an inhibitor of neuro-regeneration) in vivo via delivery of siRNA to the spinal cord using catheters.

Inhibiting smad signaling promotes neuron regeneration.
Inventors: Fan Wang, Zhigang He
USPTO Application #: 20080031911
Inhibition of Smad2/3 Signaling Promotes Axonal Regeneration after Spinal Injury in Rats-Gene Expression Knockdown in vivo!
One hour after the spinal cord is lesioned, the rats in the SB-505124 group receive a bolus injection of SB-505124 (30 mg/kg) in 0.9% saline administered via a tail vein. The treatment is repeated every 24 hours on days 1 through 7 post-lesion. Vehicle only control rats undergo the same treatment but are injected with an equal volume of 0.09% saline in a tail vein. At the same treatment time points as the SB-505124 group, the Smad2/3 siRNA group and corresponding controls receive 10 .mu.l rat Smad2/3 siRNA (Dharmacon, Lafayette, Colo.), mismatch siRNA, or transfection reagent only delivered to the spinal cord via the catheters. The siRNA (or mismatch siRNA control) complexes are prepared immediately prior to administration by mixing the RNA solution (200 .mu.M in annealing buffer) with a transfection reagent, i-Fect ™ . (Neuromics, Edina, Minn.), in a ratio of 1:4 (w:v). At this ratio, the final concentration of RNA as an RNA/lipid complex is 2 .mu.g in 10 .mu.l.

siRNA and Diabetes

I'll be keeping my eyes on this and post updates.

Quark Pharmaceuticals Announces First Patient Dosing by Pfizer in Phase II Trial of RNAi Therapy in Diabetic M
Clinical Program Leverages Quark's RNAi Technology FREMONT, Calif., July 30 /PRNewswire/ -- Quark Pharmaceuticals, Inc., a development-stage pharmaceutical company discovering and developing novel RNA interference (RNAi)-based therapeutics,...

Improving 27mer DsiRNA Performance

The DsiRNA story marches forward with yet another important publication. We will give you an opportunity to upload the fulltext article at the end of this posting.

Dr. Mark Behlke, Dr John Rossi and team have been gaining deeper understanding of the Mechanism of Dicer-substrate small-interfering RNA (DsiRNA) processing. This understanding is leading to better and better designs of the RNA duplexes. These designs or chemical modifications are necessary steps in the drug design and development process.

This publication looks at design from the perspective of:

Nuclease Stability
Pharmacokinectics
immune response

I believe this is an important publication for researchers wanting to better understand:

The mechanisms behind successful delivery of DsiRNA for gene expression studies.
Variations in potency.

upload article: oligo-18-p187-2008-collingwood-dsirna-modifications1

Coming Soon

Agenda Topics:
Target Discovery and Validation
Transfection
siRNA Therapeutics
in vivo RNAi-recent in vivo RNAi Pubs
Bioinformatics of small RNAs
siRNA library screens
microRNAs in
Disease Biology:

Stem Cell Biology

Diagnostics

Virology

Biogenesis

Development

RNAi Researchers Galvanized by Advances

Technology's Viability in Drug Development Is Finally Established
Author: Elizabeth Lipp
Publication: Genetic Engineering & biotechnology News
Publisher: Mary Ann Liebert, Inc. publishers
Date: Jun 1, 2008
Copyright © 2008 GEN Publishing

Article Link: http://www.genengnews.com/articles/chitem.aspx?aid=2493

Notable Quotables:

“Long dsRNAs have been employed for many years as a means to modulate gene expression in plants, yeast, and C. elegans,” noted Mark Behlke, M.D., Ph.D., svp of molecular genetics and CSO at Integrated DNA Technologies (IDT; www.idtdna.com).
“Similar attempts in higher organisms failed due to interferon activation, however we now know that short RNA duplexes can be safely used in mammalian systems both in vitro and in vivo. The technology has rapidly matured, thanks in large part to all that was learned over the past 20 years using antisense oligonucleotides. RNAi is now routinely employed in vivo as an experimental tool and numerous groups are vigorously pursing the use of RNAi compounds as therapeutics. Several siRNA drugs are already in clinical trials and more are in preclinical development.”

Hi Thru Put Delivery of siRNA/DsiRNA

NEW PRODUCT

i-Fect ™ Hi Put 96-New

Learn about transfection products @ neuromics