Wednesday, December 5, 2012

Using i-Fect to Silence Kv9.1 in vivo

There have been multiple publications referenced here on using Neuromics' i-Fect siRNA Delivery Kit to study the effect of silencing genes known to play a role in Pain Signaling. These include: DOR,The β3 subunit of the Na+,K+-ATPase, NTS1, NAV1.8, TRPV1 NOV, β-arrestin, TRPV1, CAV1.2 and ASIC.

I would like to highlight an exciting new study referencing how knocking down Kv9.1 Potassium Channel Subunit in vivo mediates neuropathic pain: Christoforos Tsantoulas, Lan Zhu, Yasin Shaifta, John Grist, Jeremy P. T. Ward, Ramin Raouf, Gregory J. Michael, and Stephen B. McMahon. Sensory Neuron Downregulation of the Kv9.1 Potassium Channel Subunit Mediates Neuropathic Pain following Nerve Injury. The Journal of Neuroscience, 28 November 2012, 32(48): 17502-17513; doi: 10.1523/​JNEUROSCI.3561-12.2012.

Highlights: Here, we report that the potassium channel subunit Kv9.1 is expressed in myelinated sensory neurons, but is absent from small unmyelinated neurons. Kv9.1 expression was strongly and rapidly downregulated following axotomy, with a time course that matches the development of spontaneous activity and pain hypersensitivity in animal models. Interestingly, siRNA-mediated knock-down of Kv9.1 in naive rats led to neuropathic pain behaviors. Diminished Kv9.1 function also augmented myelinated sensory neuron excitability, manifested as spontaneous firing, hyper-responsiveness to stimulation, and persistent after-discharge. Intracellular recordings from ex vivo dorsal root ganglion preparations revealed that Kv9.1 knock-down was linked to lowered firing thresholds and increased firing rates under physiologically relevant conditions of extracellular potassium accumulation during prolonged activity. Similar neurophysiological changes were detected in animals subjected to traumatic nerve injury and provide an explanation for neuropathic pain symptoms, including poorly understood conditions such as hyperpathia and paresthesias. In summary, our results demonstrate that Kv9.1 dysfunction leads to spontaneous and evoked neuronal hyperexcitability in myelinated fibers, coupled with development of neuropathic pain behaviors.

n vivo RNA interference: Anesthetized rats were subjected to a thoracic laminectomy and a silastic tube was inserted subdurally to lie just rostral to L3 DRG and externalized to deliver bolus injections (one injection per day for 4 consecutive days). Animals were allowed to recover for 5 d before treatment commenced. On the day of injection, siRNA was mixed with i-Fect (Neuromics) to a final concentration of 0.2 μg μl−1, according to published protocols (Luo et al., 2005). For each treatment, 10–20 μl of Kv9.1 siRNA or scrambled control mixture was injected, followed by a 10 μl saline flush. Twenty-four hours after the fourth injection animals were killed and L5 DRGs fresh dissected for qRT-PCR analysis. A separate set of animals were PFA perfused and DRGs retrieved for IHC. Passenger strand sequences for Kv9.1 and scrambled control siRNAs were cuuggaaucuguaggauca and gaggcctaatcgatatgtt, respectively (Dharmacon; “in vivo processing” option).
Intrathecal Kv9.1 siRNA treatment induces pain behaviors in naive rats. A, qRT-PCR quantification of Kv9.1 mRNA in rat PASMC cultures transfected with one of three Kv9.1 siRNA sequences or control siRNA (control, n = 6; siRNA, n = 3 per group; *p < 0.05 vs control, one-way ANOVA with Tukey's). B, qRT-PCR showing Kv9.1 in vivo knock-down in L5 DRG, 4 d after intrathecal delivery of siRNA #1 compared with vehicle or matched scrambled control (vehicle, n = 4; scrambled, n = 5; Kv9.1, n = 7; *p < 0.05, t test). C, IHC for Kv9.1 in scrambled- and siRNA-treated DRG to determine protein knockdown. Graphs illustrate quantification of number of positive myelinated neurons and mean Kv9.1 signal intensity (scrambled, n = 4; siRNA, n = 6; **p < 0.01, ***p < 0.001, t test). D, Kv9.1 siRNA infusion inflicts a reduction in mechanical pain withdrawal thresholds (Kv9.1, n = 7; control, n = 6; *p < 0.05, **p < 0.01, ***p < 0.001 vs scrambled control or baseline, two-way repeated measurements ANOVA with Tukey's). E, There was no change in heat pain thresholds after siRNA treatment. Vertical arrows on x-axis denote siRNA injections. All data represent mean ± SEM.
Kv9.1 knock-down triggers ectopic activity and a form of peripheral wind-up in response to stimulation. A, Schematic illustrating the positions of stimulating and recording electrodes. B, Example recordings from centrally disconnected L4/L5 strands demonstrating SA in Kv9.1 siRNA-treated or nerve-injured rats, but not in control (scrambled siRNA) animals. C, Frequency-dependent SEA (denoted by double arrowheads) in Kv9.1 siRNA-treated (middle) and injured (right), but not control (left) animals. This activity is not locked in time and can be seen in between stimulation events (vertical arrows on top of 5 Hz stimulation traces, only first 5 shown). Also note the prolonged after-discharge (AD) observed in siRNA-treated and injured animals. D, Percentage of units showing SA and SEA in control (n = 269), Kv9.1 siRNA-treated (n = 369) and injured (n = 176) animals (*p < 0.05, **p < 0.01, ***p < 0.001 vs control, χ2 test). E, Firing rate of SEA units at different stimulation frequencies (mean ± SEM; control, n = 4; siRNA, n = 22; injured, n = 17; *p < 0.05 vs control, two-way ANOVA with Tukey's). F, Quantification of AD rate per SEA unit (mean ± SEM; *p < 0.05 vs control, Mann–Whitney test).

Results propose that Kv9.1 downregulation after nerve injury may be the molecular switch controlling myelinated sensory neuron hyperexcitability. Intriguingly, a recent wide-genome association screen in humans identified a Kv9.1 polymorphism associated with susceptibility to develop chronic neuropathic pain after back surgery or leg amputation (Costigan et al., 2010), suggesting that the mechanisms described in our studies will be of direct clinical relevance to human pain. Future efforts to elucidate the precise pathways involved, combined with approaches aiming to compensate loss of Kv9.1 function, may create novel therapeutic opportunities for neuropathic pain management.

Saturday, November 17, 2012

ABCA siRNA Transfection of Neurons & Astrocytes

Neuromics' i-FectTM Transfection Kit successfully meets the challenge of transfecting neurons and astrocytes in culture. The kit has been used for gene expression analysis studies for: DOR, hTERT, The β3 subunit of the Na+,K+-ATPase, rSNSR1, NTS1. NAV1.8, , RANK, TRPV1, Survivin, Flaviviruses, NOV, Troy β-arrestin, TRPV1 CAV1.2 TLR4 and ASIC. Related publication reference use of the kit for both in vitro and in vivo studies

In this study, Dr. Marina Guizzetti and his team use our i-Fect Kit and several other commercially available kits to knockdown ABCG1 and ABCG4: Jing Chen, Xiaolu Zhang, Handojo Kusumo, Lucio G. Costa, c, Marina Guizzettia. Cholesterol efflux is differentially regulated in neurons and astrocytes: Implications for brain cholesterol homeostasis. Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids, 1831 (2), p.263-275, Feb 2013. doi:10.1016/j.bbalip.2012.09.007.
Abstract: Disruption of cholesterol homeostasis in the central nervous system (CNS) has been associated with neurological, neurodegenerative, and neurodevelopmental disorders. The CNS is a closed system with regard to cholesterol homeostasis, as cholesterol-delivering lipoproteins from the periphery cannot pass the blood–brain-barrier and enter the brain. Different cell types in the brain have different functions in the regulation of cholesterol homeostasis, with astrocytes producing and releasing apolipoprotein E and lipoproteins, and neurons metabolizing cholesterol to 24(S)-hydroxycholesterol. We present evidence that astrocytes and neurons adopt different mechanisms also in regulating cholesterol efflux. We found that in astrocytes cholesterol efflux is induced by both lipid-free apolipoproteins and lipoproteins, while cholesterol removal from neurons is triggered only by lipoproteins. The main pathway by which apolipoproteins induce cholesterol efflux is through ABCA1. By upregulating ABCA1 levels and by inhibiting its activity and silencing its expression, we show that ABCA1 is involved in cholesterol efflux from astrocytes but not from neurons. Furthermore, our results suggest that ABCG1 is involved in cholesterol efflux to apolipoproteins and lipoproteins from astrocytes but not from neurons, while ABCG4, whose expression is much higher in neurons than astrocytes, is involved in cholesterol efflux from neurons but not astrocytes. These results indicate that different mechanisms regulate cholesterol efflux from neurons and astrocytes, reflecting the different roles that these cell types play in brain cholesterol homeostasis. These results are important in understanding cellular targets of therapeutic drugs under development for the treatments of conditions associated with altered cholesterol homeostasis in the CNS.

siRNA transfection: ABCA1 SiRNA transfections: Neurons and astrocytes were transfected using the Nucleofector™ technology (Lonza/Amaxa; Walkersville, MD) as per the manufacturer's optimized protocol. In brief, primary neurons immediately after isolation, or astrocytes harvested after 7–10 days in vitro (DIV), were resuspended in Nucleofector solution. Aliquots of neurons or astrocytes were mixed with 200 pmol ABCA1 siRNA or non-targeting siRNA and were transfected using the Nucleofector programs O-007 and T-20 respectively. Exogenous cholesterol efflux was measured 96 h post transfection. ABCA1 down-regulation in ABCA1 siRNA-transfected cells was verified by Western blot. ABCG1 and ABCG4 Stealth RNAiTM siRNA transfections: on the day of transfection primary astrocytes were switched to a medium (DMEM with 10%FBS) without antibiotics and supplemented with 50 nM ABCG1 or ABCG4 siRNA, lipofectamine RNAiMAX Transfection Reagent, and Opti-MEM I according to the manufacturer's instruction for 24 h followed by the removal of the medium containing transfection reagents. Six days after preparation, primary cortical neurons were shifted to a medium (Neurobasal/B27) without antibiotic; transfection was carried out by adding to the cultures a solution containing 12 nM ABCG1 or ABCG4 SiRNA, i-Fect siRNA Transfection Reagent, and Opti-MEM I for 24 h. Exogenous cholesterol efflux was measured 48 h after the removal of the transfection reagents. The specific silencing of ABCG1 in astrocytes and neurons was confirmed by Western blot and by qRT-PCR; silencing of ABCG4 was confirmed only by qRT-PCR because no specific antibody to ABCG4 is available.

Figures: Effect of ABCG1 and ABCG4 silencing on cholesterol efflux from neurons and astrocytes. A: Primary rat cortical neurons were transfected with a non-target (NT siRNA), an ABCG1 specific siRNA (ABCG1 siRNA) or an ABCG4 siRNA using the i-Fect™ siRNA transfection reagent. B: Primary rat cortical astrocytes were transfected with an ABCG1 siRNA or an ABCG4 siRNA using lipofectamine RNAiMAX. Twenty-four hours after transfection, cells were labeled with 1 μCi/ml [3H]cholesterol for 24 h followed by a 6 h incubation with cholesterol acceptors. [3H]Cholesterol was quantified in the medium and in the cellular lipids (n=11–12). **pb0.01; ***pb0.001 compared to acceptor-matched controls by Student's t test. C: ABCG1 (left) and ABCG4 (right) mRNA levels were quantified by qPCR in neurons transfected with NT siRNA, ABCG1 siRNA or ABCG4 siRNA (n=4). D: the levels of ABCG1, ABCG4 and ABCA1 mRNA were determined by qPCR in ABCG1 siRNA-transfected (left) and ABCG4 siRNA transfected astrocytes (n=4). Representative immunoblots of ABCG1 levels (upper blots) and β-actin levels (lower blots) in neurons transfected with NT siRNA and ABCG1 siRNA (E) and astrocytes transfected with ABCG1 siRNA (F) and the densitometric quantification of ABCG1 levels normalized to β-actin from 4 independent determination (G) are shown.

The efficiency of transfection is higher in astrocytes than in neurons, it is possible that the lack of an effect of ABCG1 siRNA on cholesterol efflux from neurons may be due to the fact that ABCG1 is not sufficiently down-regulated in these cells. Further study on this phenomena is needed and are important for the discovery of druggable targets that could positively modulate cholesterol homeostasis.

Sunday, October 21, 2012

i-Fect Assisted Transfection of ASIC-siRNAs

Dr. Eric Lingueglia and his team at LabEx Ion Channel Science and Therapeutics, 06560 Valbonne, France continue to do excellent work using our i-Fect siRNA Transfection Kit. Here they use the kit to help validate the potential of a new class of three-finger peptides from the black mamba to abolish pain through inhibition of ASICs expressed either in central or peripheral neurons: Sylvie Diochot, Anne Baron, Miguel Salinas, Dominique Douguet, Sabine Scarzello, Anne-Sophie Dabert-Gay, Delphine Debayle, Valérie Friend, Abdelkrim Alloui, Michel Lazdunski, Eric Lingueglia. Black mamba venom peptides target acid-sensing ion channels to abolish pain. Nature (2012)doi:10.1038/nature11494.

...Locally designed siRNAs targeting ASIC1 (si-ASIC1a/1b, GCCAAGAAGUUCAACAAAUdtdt), ASIC2 (si-ASIC2a/2b, UGAUCAAAGAGAAGCUAUUdtdt) and ASIC2a (si-ASIC2a, AGGCCAACUUCAAACACUAdtdt) have been validated in vitro in COS-7 cells transfected with myc-ASIC1a, ASIC1b, myc-ASIC2a or myc-ASIC2b, and the relevant siRNA or a control siRNA (si-CTR, GCUCACACUACGCAGAGAUdtdt) with TransIT-LT1 and transIT-TKO (Mirus), respectively. Cells were lysed 48 h after transfection and processed for western blot analysis to assess the amount of ASIC1a protein with the anti-Myc A14 antibody (1:500; Santa Cruz Biotechnology) or the anti-ASIC1 antibody (N271/44; 1:300; NeuroMab) and a monoclonal antibody against actin (AC-40; 1:1,000; Sigma) as a loading control. siRNAs were intrathecally injected into mice (2 µg per mouse at a ratio of 1:4 (w/v) with i-Fect (Neuromics)) twice a day for 3 days. After 3 days of treatment, the paw-flick latency was measured and the residual effect of mambalgin-1 (intrathecal or intraplantar, 34 µM) or the carrageenan (intraplantar, 2%)-induced hyperalgesia was tested. For validation of the in vivo effect of the siRNAs, lumbar DRGs or lumbar dorsal spinal cord were removed after the last siRNA injection for total RNA isolation (RNeasy kits, Qiagen) followed by cDNA synthesis (AMV First-Strand cDNA synthesis kit (Invitrogen) and High Capacity RNA-to-cDNA Kit, (Applied Biosystems)). The relative amounts of ASIC transcripts were evaluated by quantitative reverse-transcription PCR in a Light-Cycler 480 (Roche Products). Pre-designed and validated TaqMan assays for ASIC1 (ASIC1a and ASIC1b; Mm01305998_mH), ASIC1a (Mm01305996_m1), ASIC2 (ASIC2a and ASIC2b; Mm00475691_m1), ASIC3 (Mm00805460_m1) and 18S ribosomal RNA (Mm03928990_g1) were from Applied Biosystems. Each cDNA sample was run in triplicate and results were normalized against 18S and converted to fold induction relative to control siRNA treatment...

Sunday, July 29, 2012

i-Fect and the Study of Glomerulosclerosis (Kidney Disease)

in vitro RANK knockdown system to determine whether RANK was necessary for podocyte survival.

Our i-FectTM Transfection Kit is widely used and frequently published as a potent tool for gene expression analysis. In this study i-Fect was used to consistently achieved close to 71.6% siRNA transfection efficiency in podocytes: Shuangxin Liu, Wei Shi, Houqin Xiao, Xinling Liang, Chunyu Deng, Zhiming Ye, Ping Mei, Suxia Wang, Xiaoying Liu, Zhixin Shan, Yongzheng Liang, Bin Zhang, Wenjian Wang, Yanhui Liu, Lixia Xu, Yunfeng Xia, Jianchao Ma, Zhilian Li. Receptor Activator of NF-kappaB and Podocytes: Towards a Function of a Novel Receptor-Ligand Pair in the Survival Response of Podocyte Injury. PLoS ONE: Research Article, published 25 Jul 2012 10.1371/journal.pone.0041331......RANK small interference RNA (siRNA) knockdown was performed by using transient transfection of pooled, functionally validated Cy3–labeled RANK siRNA (Invitrogen) [16]. Podocytes that were differentiated for 10 to 12 d were maintained at 10% FBS/RPMI as described above, and transfected using the RANK siRNA transfection reagent (Neuromics). For determination of the transfection efficiency, a Cy3–labeled RANK siRNA was analyzed by flow cytometry. Western blot analysis for RANK was performed with samples from cells 24 to 96 h after the transfection. Several concentrations of RANK siRNA (20, 40, and 60 nM) were tested to determine optimal knockdown conditions...
Data Highlights: To better understand RANK function in immortalized mouse podocytes, we used an in vitro RANK knockdown system to determine whether RANK was necessary for podocyte survival [33]. We consistently achieved close to 71.6% siRNA transfection efficiency in podocytes, as visualized by transfecting a fluorescently tagged Cy3-RANK siRNA. Flow cytometry fluorescence of podocytes not transfected with siRNA-Cy3 was measured as negative control; the value in podocytes was 4.1% (Figure 5A,5B and 5C). Knockdown of RANK was determined to be maximal between days 3 and 4 after transfection (Figure 5D). We did not observe any morphologic changes between cells with or without RANK siRNA knockdown during the 4 d after transfection. To test whether RANK was involved in the apoptosis of podocytes in vitro, we studied podocytes apoptosis before and after stable knockdown of RANK with siRNA. The knockdown of RANK alone did not induce podocytes apoptosis, but increased mildly the apoptosis of podocytes exposed to PA. However, RANKL reduced apoptosis of podocytes transfected with RANK siRNA exposed to PA compared with control siRNA (RANK siRNA 16.5±1.5% versus control siRNA 24.0±1.8%, p<0.01, Figure 5E).

Images: RANKL and RANK Protects Mouse Podocytes from Apoptosis.(A) Mouse podocytes were transfected with RANK siRNA at a concentration of 100 nM. (B) Flow cytometry fluorescence of podocytes not transfected with siRNA-Cy3 was measured as negative control; the value in podocytes was 4.1%. (C) Transfection efficiency was measured by counting fluorescence-positive cells by flow cytometry; the value in podocytes was 71.6%. (D) RANK immunoblotting of podocytes revealed that RANK was downregulated with RANK siRNA. RANK protein was low abundance in the podocytes 3 d after transfection (lane 1 and lane 2). (E) The percentage of apoptotic cells was measured by flow cytometry. In cells transfected with RANK siRNA, RANK knockdown was associated with mild increase in apoptosis compared with control siRNA (24.0±1.8% versus 22.8±1.1%; p>0.05) after podocytes were exposed to PA. However, RANKL (40 ng/ml) decreased PA-induced apoptosis of podocytes with RANK siRNA (RANKL 16.5±1.5% versus control 22.8±1.1%). (F) Quantification of apoptosis of podocytes with PA and RANKL. Apoptosis was measured by flow cytometry in control podocytes without PA induction (G) (8.7±0.97%) and podocytes that were exposed to RANKL (40 ng/ml) without PA after 48 h (H) (5.7±0.81%). (I) PA increased the apoptosis of podocytes. Apoptosis was measured by flow cytometry of podocytes exposed to PA (25 µg/ml) for 48 h (26.3±3.6%). (J) Exogenous RANKL protected podocytes from PA induction apoptosis. RANKL (40 ng/ml) decreased PA-induced apoptosis (15.5±2.2%). All the experiments were conducted in three times. **Compared with control, p<0.01; *Compared with control, p<0.05.

The upregulation of RANKL and RANK, in combination with the significant protective effects of RANKL, indicates that RANK is part of an adaptive, recovery response to podocyte injury. This is the first observation that RANKL, acting through RANK, functions in an injury paradigm in the kidney. These data raise the exciting therapeutic possibility of giving exogenous RANKL to patients with glomerular disease that is characterized by a loss of podocytes, such as membranous nephropathy and focal segmental glomerulosclerosis.

Thursday, May 24, 2012

i-Fect, Troy, Microglia and Glioblastomas

Neuromics' i-FectTM delivers siRNA to Microglia in Culture.

I have reported success with using i-Fect both in vitro and in vivo. I am excited about the results featured in this publication as Neurons and Glia are particulary tough to transfect with siRNA. I congratulate the researchers for successfully knocking down the Troy gene in vitro: Jacobs VL, Liu Y, De Leo JA (2012) Propentofylline Targets TROY, a Novel Microglial Signaling Pathway. PLoS ONE 7(5): e37955. doi:10.1371/journal.pone.0037955.

Highlights: "We demonstrate that inhibition of TROY expression in microglia by siRNA transfection significantly inhibits microglial migration towards CNS-1 cells similar to 10 µM propentofylline treatment. These results identify TROY as a novel molecule expressed in microglia, involved in their migration and targeted by propentofylline. Furthermore, these results describe a signaling molecule that is differentially expressed between microglia and macrophages in the tumor microenvironment."

Protocol: Small interference RNA (siRNA) oligonucleotides specific for TROY (#1:s144862, #2:s144863, #3:s144864) were validated by and purchased from Invitrogen (Grand Island, NY). Transient transfection was carried out using iFect (Neuromics Edina, MN) as previously described [J Am Soc Nephrol 17: 1543–1552]. Briefly, microglia were plated at 3×105 cells/well in a 12-well plate. Once cells had adhered, they were transfected with 1 µg siRNA. Control samples were treated with empty vector siRNA (Sigma St Louis, MO) or iFect reagent alone. Cells were left in microglia media (10% fetal bovine serum (Hyclone Logan, UT), 1.1% GlutaMax (Invitrogen Carlsbad, CA), and 1% penicillin/streptomycin (100 U/ml penicillin, 100 µg/ml streptomycin, Mediatech, Manassas, VA)) at 37°C with 5% CO2 overnight and then used the following day for experiments.

Images: (A) Western blot demonstrating decreased TROY expression in microglia cultured with CNS-1 conditioned media and treated with TROY siRNA. (B) Microglia were treated with TROY siRNA, and then migrated towards CNS-1 cells. Migration of microglia in response to CNS-1 cells is significantly decreased compared to media (* = p<0.05).

Check out all pubs referencing use of i-Fect.

Tuesday, April 24, 2012

Tuesday, February 28, 2012

pn-Fect and Transfection of DRG cultures

In Vitro Gene expression analysis assays are essential for understanding how up or down regulation of  related target proteins could result in pathologies. Dorsal Root Ganglion (DRG), Neuronal and Glial Cultures have proven hard to transfect as as many transfection reagents are toxic to these cells. It is important for the study of neuro-diseases that researchers have tools and methods that enable success.

In this study, researchers successfully transfect DRG cultures with IKAP-shRNA using our pn-Fect kit. The own regulation of IKAP in these cultures support findings that helped explain the potential pathology of Familial Dysautonomia (FD; Hereditary Sensory Autonomic Neuropathy; HSAN III): Hunnicutt BJ , Chaverra M , George L , Lefcort F , 2012 IKAP/Elp1 Is Required In Vivo for Neurogenesis and Neuronal Survival, but Not for Neural Crest Migration. PLoS ONE 7(2): e32050. doi:10.1371/journal.pone.0032050.

Cell culture: Dorsal root ganglia were dissected from Embryonic day 5–9.5 chick embryos (E5–9.5) and dissociated by incubation in 0.25% trypsin-EDTA (Gibco) for 7 min at 37 C followed by trituration through fire–pulled glass pipettes. The culture media consisted of Neurobasal medium (Invitrogen) supplemented with B27 (1X,Invitrogen), Glutamax (1X,Invitrogen), Hybrimax Antibiotic\Antimicotic (1:100, Sigma), NGF (10 ng/ml, gift from Dr. Thomas Large). Cells were plated on 8-well Nunc glass chamber slides that were coated with poly-D-lysine (1:100, Sigma) and laminin 20 ug/ml (Gibco). Approximately equal numbers of cells (52,500) were plated per well. Immediately after plating, cells were transfected with IKBKAP-7.4 shRNA or control shRNA via pn-Fect (Neuromics, PN3375). Several ratios of pnfect:DNA were tested with the optimum obtained 1.84:1. The cells were then cultured for approximately 29 h at 37 C, 5.5% C02. After incubation culture cells were fixed and inmunostained as previously described [24]. To determine whether IKBKAP shRNAs altered cell proliferation and/or neuronal differentiation in dissociated DRG cultures, Brdu was added to the cultures and the cells were fixed 24 hrs later (as described in [24]). The number of GFP+/BrdU+ or GFP+/Tuj-1+ cells were quantified for each experiment, and a ratio comparing control vs. IKBKAP shRNAs for each experiment determined. For the BrdU+ experiment, a total of 556 GFP+/control shRNA transfected cells were counted and 357 GFP+/IKBKAP shRNA transfected cells in 3 separate experiment. For determining neuronal differentiation, a total of 2866 GFP+/control shRNA transfected cells and 2913 IKBKAP shRNA transfected cells were counted, over 3 separate experiments.

Images: IKAP regulates neuronal differentiation in the DRG. Reduction in IKAP leads to increased numbers of neurons in the immature DRG (A–C). Embryos at St. 12 were transfected with either control shRNAs or IKBKAP shRNAs and analyzed at St 24/25. Embryos were sectioned, and immunolabled with the neuronal markers Tuj-1 or Ben and the percentage of GFP+ neurons determined. Significantly more IKBKAP shRNA transfected DRG precursor cells differentiated into neurons (arrows in B; IKBKAP shRNA 7.4; n = 3 embryos; p = 0.002; IKBKAP shRNA 1.6 & 4.5, n = 3 embryos; p = 0.001) than Control shRNA transfected DRG precursor cells (n = 5 embryos). (D–H) IKBKAP shRNA-transfected DRG precursor cells (n = 3 embryos; 252 cleaved-Caspase 3+ cells counted) were also more likely to die by apoptosis (compare D & E to F & G) than control shRNA-electroporated cells (n = 3 embryos; 117 cleaved caspase-3+ cells counted). (H) The number of cleaved Caspase 3+ cells was quantified in DRG on both the transfected side of the embryo and the non-transfected side of the embryo and a ratio determined. Significantly more cleaved-Caspase 3+ cells were present in the transfected DRG of IKBKAP shRNA transfected embryos than in the transfected DRG in embryos transfected with control shRNAs; p = 0.006. (I–N). Over-expression of the c-terminus of IKAP prevents neural crest cells from coalescing with the DRG (I, K, L; p = 0.004) but the few that do join, tend not to differentiate into neurons (p = 0.007; J, M, N). Embryos were transfected with either a construct driving expression of the c-terminus of chicken IKAP with a His tag (CT-IKAP-His; L,N) or a control, His-tagged construct (K, M) and analyzed at St. 21. The location and neuronal identity of transfected cells was determined in 3 embryos for each treatment; Control His-plasmid: n = 343 transfected cells counted; CT-IKAP-His: n = 278 transfected cells counted. Statistical analysis by Student t-test. doi:10.1371/journal.pone.0032050.g006. 

Check out our transfection reagents and capabilities. We will continue to post publications and data that support and add to our capabilities.

Sunday, February 26, 2012

Silencing NOV in vivo using i-Fect

Implications for Treating Neuropathic or Inflammatory Pain

It has been a awhile since I posted results here for researchers using Neuromics' i-Fect ™ siRNA Transfection Kits. Over the past months, we have enjoyed more growth in use of these kits so I anticipate more positive results to come.

Inflammation plays and evil role in Neuropathic Pain. Sustained neuroinflammation cased by  release of pro-inflammatory cytokines and chemokines (including TNF-α, IL-1β, IL-6 and CCL2). Emerging studies have established that the extracellular matrix (ECM) components, particularly matrix metalloproteinases (MMPs) actively participate in the generation and maintenance of pain.
In this study, investigators show how modulating expression of nephroblastoma overexpressed gene (NOV) can mitigate expression of the MMPs and thus regulate Pain: Lara Kular, Cyril Rivat, Brigitte Lelongt, Claire Calmel, Maryvonne Laurent, Michel Pohl, Patrick Kitabgi, Stephane Melik-Parsadaniantz and Cecile Martinerie. NOV/CCN3 attenuates inflammatory pain through regulation of matrix metalloproteinases-2 and -9. Journal of Neuroinflammation 2012, 9:36 doi:10.1186/1742-2094-9-36.
Results:  NOV was expressed in neurons of both dorsal root ganglia (DRG) and dorsal horn of the spinal cord (DHSC). After intraplantar CFA injection, NOV levels were transiently and persistently down-regulated in the DRG and DHSC, respectively, occurring at the maintenance phase of pain (15 days). NOV-reduced expression was restored after treatment of CFA rats with dexamethasone. In vitro, results based on cultured DRG neurons showed that siRNA-mediated inhibition of NOV enhanced IL-1beta- and TNF-alpha-induced MMP-2, MMP-9 and CCL2 expression whereas NOV addition inhibited TNF-alpha-induced MMP-9 expression through beta1 integrin engagement. In vivo, the intrathecal delivery of MMP-9 inhibitor attenuated mechanical allodynia of CFA rats. Importantly, intrathecal administration of NOV siRNA specifically led to an up-regulation of MMP-9 in the DRG and MMP-2 in the DHSC concomitant with increased mechanical allodynia. Finally, NOV intrathecal treatment specifically abolished the induction of MMP-9 in the DRG and, MMP-9 and MMP-2 in the DHSC of CFA rats. This inhibitory effect on MMP is associated with reduced mechanical allodynia.
Conclusions:  This study identifies NOV as a new actor against inflammatory pain through regulation of MMPs thus uncovering NOV as an attractive candidate for therapeutic improvement in pain relief.

Figure 9. Effect of in vivo endogenous NOV inhibition on MMP-2/-9 expression and mechanical allodynia. In CFA rats, NOV-specific siRNA (2 μg) or control non-silencing siRNA (Ctr) were delivered intrathecally (i.t) daily for 3 consecutive days. (A) NOV protein levels in DHSC. Representative western blot (left panel) and quantification of protein levels normalized to GAPDH (right panel) (**P <0.01, siNOV versus Ctr, n = 6) (B, C) Levels of MMP-9 and MMP-2 mRNA in DRG (B) and DHSC. (C) Transcript levels were quantified by RT-qPCR and values were normalized to rat S26 mRNA level. Data represent the mean value ± SEM of two independent experiments realized with three rats per condition (*P <0.05 siNOV versus Ctr). (D) Representative gelatin zymograph showing MMP-9 and MMP-2 activities in DRG (left panel) and quantification of MMP-2 and MMP-9 gelatinolytic bands (right panel). Data represent the mean ± SEM of six rats per group (**P <0.01 siNOV versus Ctr). (E) Paw withdrawal threshold (g) of CFA rats intrathecally injected with NOV-specific siRNA or control siRNA evaluated using the von Frey test. Data represent the mean ± SEM of eight rats per group (*P <0.05 siNOV- versus Ctr-treated rats), BL: baseline In order to test whether endogenously produced NOV could modulate inflammatory pain, we evaluated the mechanical allodynia of CFA rats treated with NOV. As shown in Figure 9E, intrathecal delivery of siNOV resulted in a significant increase of mechanical allodynia compared to rats injected with control siRNA (*P <0.05, n = 8). These data strongly suggest that endogenously produced NOV influences pain intensity and further support the hypothesis that NOV downregulation could participate in pain processes through
upregulation of MMP-2 and MMP-9.

Learn more about Neuromics' Transfection Reagents!

Monday, February 13, 2012

In Vivo application of RNAi to study pain

This overview is from 2010. I am posting a link because it undercores the need to have transfection reagents that have the ability to deliver small doses of siRNA in vivo.
"One of the biggest challenges in using RNAi in pain research is delivery of siRNA to the CNS in sufficient concentrations. This obstacle exists because siRNA by itself does not cross the blood brain barrier (BBB) and is degraded in the blood by endonucleases. Intravenous or oral administration is, therefore, inadequate to achieve desired protein knockdown. The use of transfection agents and intrathecal delivery has enhanced siRNA uptake by target tissues in recent studies." Zachary J Clark, Gurwattan S. Miranpuri, Daniel K Resnick. In Vivo application of RNAi to study pain. Annals of Neurosciences, Volume 17, Number 3, July 2010.

Please click through the link and you will learn of techniques currently used to delivery siRNA in vivo for pain research.

Saturday, February 4, 2012

siRNA Delivery Group on Linkedin

I wanted to make readers aware of an excellent discussion group on Linkedin named "siRNA Delivery". Included are tip, updates on commercialization and key publications.

Here're some examples:
Happy reading.