Bidirectional integrative regulation of Cav1.2 calcium channel by microRNA miR-103: role in pain

I have reported use of our i-FectTM siRNA delivery kit for gene expression analysis studies of DOR, hTERT, The β3 subunit of the Na+,K+-ATPase, rSNSR1, NTS1. NAV1.8, , TRPV1, Survivin, Flaviviruses and more.

I am pleased to add the Cav1.2 calcium channel to this growing list. Congratulations to Dr. Marc Landry for discovering the interplay between microRNA-miR-103 and this calcium channel: Alexandre Favereaux, Olivier Thoumine, Rabia Bouali-Benazzouz, Virginie Roques, Marie-Amélie Papon, Sherine Abdel Salam, Guillaume Drutel, Claire Léger, André Calas, Frédéric Nagy and Marc Landry. Bidirectional integrative regulation of Cav1.2 calcium channel by microRNA miR-103: role in pain. The EMBO Journal , (29 July 2011) | doi:10.1038/emboj.2011.249.

Abstract: Chronic pain states are characterized by long-term sensitization of spinal cord neurons that relay nociceptive information to the brain. Among the mechanisms involved, up-regulation of Cav1.2-comprising L-type calcium channel (Cav1.2-LTC) in spinal dorsal horn have a crucial role in chronic neuropathic pain. Here, we address a mechanism of translational regulation of this calcium channel. Translational regulation by microRNAs is a key factor in the expression and function of eukaryotic genomes. Because perfect matching to target sequence is not required for inhibition, theoretically, microRNAs could regulate simultaneously multiple mRNAs. We show here that a single microRNA, miR-103, simultaneously regulates the expression of the three subunits forming Cav1.2-LTC in a novel integrative regulation. This regulation is bidirectional since knocking-down or over-expressing miR-103, respectively, up- or down-regulate the level of Cav1.2-LTC translation. Functionally, we show that miR-103 knockdown in naive rats results in hypersensitivity to pain. Moreover, we demonstrate that miR-103 is down-regulated in neuropathic animals and that miR-103 intrathecal applications successfully relieve pain, identifying miR-103 as a novel possible therapeutic target in neuropathic chronic pain.

MicroRNAs as targets for pain therapies are gathering momentum. This defned miR-103 is a compelling possibilty. I will be following the story closely as it unfolds.

Using MATRa for siRNA Transfection of Carcinoma Cell Lines

MATRa^TM -Magnet Assisted Transfection is an easy-to-handle, very fast and highly efficient technology to transfect cells in culture with siRNA. Multiple successes with the system includes Carcinoma Cell Lines.

Efficient transient transfection of siRNA in head and neck cancer cells. The cell line ANT-1 was transiently transfected with MATra-A (1 µl/1 µg DNA) in a 6 well format (5 x 105 cells/cavity) with siRNA against protein 1 (100 nM). After 24 hours total RNA was isolated and expression of protein 1-specific mRNA determined by RT-PCR (upper lane). SiRNA 13 are three different oligonucleotide sequences. Control for consistent loading and cDNA quality: expression of ubiquitary GAPDH mRNA (lower lane).
Protein 2 expression in head and neck cancer cells GHD-1. GHD-1 cells (5 x 105 cells/cavity of a 6 well plate) were transiently transfected with two different siRNAs against protein 2. Expression of protein 2 was detected with specific antibodies in an immunoblot 72 hours after transfection with MATra-A (1 µl / 1 µg DNA). As control ubiquitary β-actin was detected as well.
Treating the carcinoma cells with specific siRNA caused a clear inhibition of protein 1/protein 2 expression which indicates high transfection efficiencies.
(Data kindly provided by Rauch, Schaffrik, Ahlemann and Gires, LMU Munich and GSF, Munich, Germany).

"After having tested MATra in a variety of experimental set ups we can summarize the following advantages: High transfection efficiency   Easier to handle   High reproducibility Serum compatibility Low sensibility against cell confluence" Dr. Oliver Gires, LMU Munich, Germany