Silencing Cytokines in-vivo with i-Fect

Knocking Down Cytokines to Study Pain Response

We have many unique applications published by researchers using our Transfection Kits in vitro and in vivo. Here researchers simultaneously silence 3 immune/inflammatory response cytokines in vivo: Byung Moon Choi, Soo Han Lee, Sang Mee An, Do Yang Park, Gwan Woo Lee, and Gyu-Jeong Noh. The time-course and RNA interference of TNF-α, IL-6, and IL-1β expression on neuropathic pain induced by L5 spinal nerve transection in rats. Korean J Anesthesiol. 2015 Apr;68(2):159-169. English. Published online March 30, 2015. http://dx.doi.org/10.4097/kjae.2015.68.2.159.

Protocol: RNAs were administered as described, with modifications [11]. A cocktail of siRNA simultaneously targeting TNF-α (Silencer® Select siRNA; s128522, Ambion, Austin, TX, USA), IL-6 (Silencer® Select siRNA; s217844, Ambion, Austin, TX, USA) and IL-1b (Silencer® Select siRNA; s127941, Ambion, Austin, TX, USA), as well as a control siRNA (Silencer® Negative Control #1 siRNA; Cat #4635, Ambion, Austin, TX, USA), were prepared immediately prior to administration by mixing the RNA (200 µM) with the transfection reagent, i-Fect™ (Neuromics, Minneapolis, MN, USA), in a ratio of 1 : 5 (w : v). At this ratio, the final RNA/lipid complex concentration was 2 µg in 5 µl for each cytokine siRNA and 6 µg in 15 µl for the control siRNA. The cytokine siRNAs were combined and they and the control siRNA (15 µl each) were delivered to the lumbar region of the spinal cord via the intrathecal catheters. Injections were given daily on 5 consecutive days (-1, 0, 1, 2, 3 d after L5 SNT.

The changes in mechanically induced allodynia and hyperalgesia in the rats surviving for 6 d after SNT are shown in figure. Allodynia and hyperalgesia were lower in the COCK group than in the CON group by 2 d after SNT (P < 0.05) and the difference was maintained for the duration of the experiment.

Figure: The time course of mechanical allodynia (A) and hyperalgesia (B) in the ipsilateral hind paw of rats undergoing L5 spinal nerve transection (SNT) after the administration of control siRNA (CON group) or a cocktail of small interfering RNAs (siRNA) targeting TNF-α, IL-6 and IL1-β (COCK group). The data on the rats surviving for 6 d after SNT are expressed as mean ± SE. -1: 1 d prior to SNT, 0: the day of L5 SNT, 1, 2, 4 and 6: 1, 2, 4 and 6 d after L5 SNT. *P < 0.05 vs. CON group at each time point. MPE: maximal possible effect. The cut-off values for mechanical allodynia and hyperalgesia are 30 g and 250 g, respectively.

We will continue to post new applications and methods published by researchers using our Transfection Kits.

β-arrestin siRNA Delivery in vivo and Increased Analgesia

I have reported use of our i-FectTM siRNA delivery kit for gene expression analysis studies of Cav1.2, DOR, hTERT, The β3 subunit of the Na+,K+-ATPase, rSNSR1, NTS1. NAV1.8, , TRPV1, Survivin, Flaviviruses and more.

I would like to congratulate Dr. C.R. Lin and his team at National Taiwan University College of Medicine for silencing β-arrestin expression in vivo and the impact on opioid based analgesia. The results could be good news for improving opioid based pain therapies: C.-H.Yang, H.-W. Huang, K.-H.Chen, Y.-S.Chen, S.-M.Sheen-Chen and C.-R.Lin. Antinociceptive potentiation and attenuation of tolerance by intrathecal β-arrestin 2 small interfering RNA in rats. Br. J. Anaesth. (2011) doi: 10.1093/bja/aer291.

Background: Tolerance to the analgesic effect of opioids complicates the management of persistent pain states. We tested whether the intrathecal infusion of small interfering RNA (siRNA) against β-arrestin 2 would reduce tolerance to chronic morphine use and the severity of precipitated morphine withdrawal.

Methods: Intrathecal β-arrestin 2 (2 μg siRNA per 10 μl per rat) was injected once daily for 3 days. Rats then received a continuous intrathecal infusion of morphine (2 nmol h−1) or saline for 7 days. Daily tail-flick (TF) and intrathecal morphine challenge tests were performed to assess the effect of intrathecal β-arrestin 2 siRNA on antinociception and tolerance to morphine. Naloxone withdrawal (2 mg kg−1) was performed to assess morphine dependence.
Results: In the daily TF test, the antinociception of intrathecal morphine was increased and maintained in rats receiving β-arrestin 2 siRNA compared with the control group (morphine alone). In the probe response test, rats receiving morphine infusion with β-arrestin 2 siRNA treatment showed a significant left shift in their dose–response curve, as measured by per cent maximal possible effect (MPE), such that the AD50 was significantly decreased by a factor of 5.6 when compared with that of morphine-infused rats. In the naloxone-induced withdrawal tests, rats receiving β-arrestin 2 siRNA injection with morphine infusion showed a significant reduction in four of the six signs of withdrawal.
Conclusions: We show here that intrathecal β-arrestin 2 siRNA in rats enhances analgesia and attenuates naloxone-induced withdrawal symptoms. This may warrant further investigation in the context of long-term use of intrathecal opioids for controlling chronic pain.