Nanoparticles for targeted delivery of therapeutics and small interfering RNAs in hepatocellular carcinoma

Hepatocellular carcinoma(HCC) is the 5th most common malignancy which is responsible for more than half million annual mortalities; also, it is the third leading cause of cancer related death. Unfavorablesystemic side-effects of chemotherapeutic agents and susceptibility to the degradation of small interfering RNAs(si RNAs), which can knock down a specific gene involved in the disease, have hampered their clinical application. So, it could be beneficial to develop an efficient carrier for the stabilization and specific delivery of drugs and si RNA to cells. Targeted nanoparticles have gained considerable attention as an efficient drug and gene delivery system, which is due to their capability in achieving the highest accumulation of cytotoxic agents in tumor tissue, modifiable drug pharmacokinetic- and bio-distribution, improved effectiveness of treatment, and limited sideeffects. Recent studies have shed more light on the advantages of novel drug loaded carrier systems vs free drugs. Most of the animal studies have reported improvement in treatment efficacy and survival rate using novel carrier systems. Targeted delivery may be achieved passively or actively. In passive targeting, no ligand as homing device is used, while targeting is achieved by incorporating the therapeutic agent into a macromolecule or nanoparticle that passively reaches the target organ. However, in active targeting, the therapeutic agent or carrier system is conjugated to a tissue or cell-specific receptor which is overexpressed in a special malignancy using a ligand called a homing device. This review covers a broad spectrum of targeted nanoparticles as therapeutic and nonviral si RNA delivery systems, which are developed for enhanced cellular uptake and targeted gene silencing in vitro and in vivo and their characteristics and opportunities for the clinical applications of drugs and therapeutic si RNA are discussed in this article. Asialoglycoprotein receptors, low-density lipoprotein, ganglioside GM1 cell surface ligand, epidermal growth factor receptor receptors, monoclonal antibodies, retinoic acid receptors, integrin receptors targeted by Arg-Gly-Asp peptide, folate, and transferrin receptors are the most widely studied cell surface receptors which are used for the site specific delivery of drugs and si RNA-based therapeutics in HCC and discussed in detail in this article.

Therapeutic potential of small interfering RNAs/micro interfering RNA in hepatocellular carcinoma

Hepatocellular carcinoma(HCC) is the predominant form of primary liver cancer and represents the third leading cause of cancer-related death worldwide. Current available therapeutic approaches are poorly effective,especially for the advanced forms of the disease. In the last year,short double stranded RNA molecules termed small interfering RNAs(si RNAs) and micro interfering RNAs(mi RNA),emerged as interesting molecules with potential therapeutic value for HCC. The practical use of these molecules is however limited by the identification of optimal molecular targets and especially by the lack of effective and targeted HCC delivery systems. Here we focus our discussion on the most recent advances in the identification of si RNAs/mi RNAs molecular targets and on the development of suitable si RNA/mi RNAs delivery systems.

Small interfering RNA targeting PGC-1α inhibits VEGF expression and tube formation in human retinal vascular endothelial cells

AIMTo determine whether small interfering RNA (siRNA) of PGC-1α could inhibit vascular endothelial growth factor (VEGF) expression and tube formation in human retinal vascular endothelial cells (hRVECs).METHODShRVECs transfected with peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) siRNA were incubated for 24h and then placed into a normoxic (20%, O2) or hypoxic (1%, O2) environment for another 16h. PGC-1α mRNA and protein levels were detected by real-time PCR and Western blot. VEGF mRNA and protein levels were detected by real-time PCR and ELISA. Cell proliferation was evaluated by BrdU incorporation assay. Forty-eight hours after siRNA transfection, hRVECs were planted into Matrigel-coated plates and cultured under normoxic (20%, O2) or hypoxic (1%, O2) conditions for another 48h. The tube formation of hRVECs was observed under an optical microscope and quantified by counting the number of branch points and calculating the total tube length.RESULTSPGC-1α mRNA and protein levels were significantly reduced by PGC-1α siRNA, and VEGF mRNA and protein levels also decreased significantly. The percentage of BrdU-labeled cells in siPGC-1α groups were significantly decreased compared with control siRNA groups under normoxia and hypoxia in cell proliferation assay. In the tube formation assay, PGC-1α siRNA treated cells formed significantly fewer tubes.CONCLUSIONBlocking PGC-1α expression can inhibit VEGF expression in hRVECs and inhibit their ability to form tubes under both normoxic and hypoxic conditions.

Impact of Bovine Skeletal Muscle Satellite Cell Differentiation by Small Interfering RNA Targeting Myogenin Gene

To examine the effect of myogenin gene on the differentiation of bovine skeletal muscle satellite cell, we constructed small interfering RNA plasmid vector to obtain myogenin knockdown bovine skeletal muscle cells, then used cell transfection, real time RCR and Western Blot to detect the influence of myogenin to cell differentiation. Results showed that the knockdown of myogenin significantly decreased its expression and other muscle-specific genes. Compared to the control, it could differentiate into few myotubes when challenged by low serum in the medium. These findings provided an important theoretical basis for further explore of the genetic mechanism in adult skeletal muscle, the remedy of muscle injuries and the cultivation of high-yield transgenic cattle.

Inhibition of genes expression of SARS coronavirus by synthetic small interfering RNAs

RNA interference (RNAi) is triggered by the presence of a double-stranded RNA (dsRNA), and results in the silencing of homologous gene expression through the specific degradation of an mRNA containing the same sequence. dsRNAmediated RNAi can be used in a wide variety of eucaryotes to induce the sequence-specific inhibition of gene expression.Synthetic 21-23 nucleotide (nt) small interfering RNA (siRNA) with 2 nt 3' overhangs was recently found to mediate efficient sequence-specific mRNA degradation in mammalian cells. Here, we studied the effects of synthetic siRNA duplexes targeted to SARS coronavirus structural proteins E, M, and N in a cell culture system. Among total 26 siRNA duplexes, we obtained 3 siRNA duplexes which could sequence-specifically reduce target genes expression over 80％ at the concentration of 60 nM in Vero E6 cells. The downregulation effect was in correlation with the concentrations of the siRNA duplexes in a range of 0～60 nM. Our results also showed that many inactive siRNA duplexes may be brought to life simply by unpairing the 5' end of the antisense strands. Results suggest that siRNA is capable of inhibiting SARS coronavirus genes expression and thus may be a new therapeutic strategy for treatment of SARS.

Combination of small interfering RNAs mediates greater suppression on hepatitis B virus cccDNA in HepG2.2.15 cells

AIM: To observe the inhibition of hepatitis B virus (HBV) replication and expression in HepG2.2.15 cells by combination of small interfering RNAs (siRNAs). METHODS: Recombinant plasmid psil-HBV was constructed and transfected into HepG2.2.15 cells. At 48 h,72 h and 96 h after transfection,culture media were collected and cells were harvested for HBV replication assay. HBsAg and HBeAg in the cell culture medium were detected by enzyme-linked immunoadsorbent assay (ELISA). Intracellular viral DNA and covalently closed circular DNA (cccDNA) were quantifi ed by real-time polymerase chain reaction (PCR). HBV viral mRNA was reverse transcribed and quantifi ed by reverse-transcript PCR (RT-PCR). RESULTS: siRNAs showed marked anti-HBV effects. siRNAs could specifically inhibit the expression of HBsAg and the replication of HBV DNA in a dose-dependent manner. Furthermore,combination of siRNAs,compared with individual use of each siRNA,exerted a stronger inhibition on antigen expression and viral replication. More importantly,combination of siRNAs significantly suppressed HBV cccDNA amplifi cation. CONCLUSION: Combination of siRNAs mediates a stronger inhibition on viral replication and antigenexpression in HepG2.2.15 cells,especially on cccDNA amplifi cation.

KNOCKDOWN OF SURVIVIN EXPRESSION BY SMALL INTERFERING RNA SUPPRESSES PROLIFERATION OF TWO HUMAN CANCER CELL LINES

客观：对 survivin 构造小介入 RNA (siRNA ) 的表示向量并且在 survivin 表示和人的胰腺的癌症房间线 PC-2 和乳癌房间线 MCF-7 的增长上观察它的效果。方法：对 survivin 和 transfected 构造了 siRNA 的表示向量它进用 lipofectamine 的 PC-2 和 MCF-7 房间 2000。survivin 的表示被 semi-quantitive RT-PCR 和免疫组织化学检测，并且它 PC-2 和 MCF-7 房间的增长上的效果被 MTT 试金检测。结果：顺序特定的 siRNA 的介绍能高效地在二根癌症房间线在 mRNA 和蛋白质层次压制 survivin 表示。在 PC-2 房间，表示抑制率在 mRNA 水平是 81.25% ， 74.24% 在蛋白质铺平。在 MCF-7 房间，表示抑制率在 mRNA 水平是 64.91% ， 79.72% 在蛋白质铺平。PC-2 和 MCF-7 房间的增长也被压制，并且在房间以后的 24 和 48 个小时被重新播种 PC-2 房间的增长抑制率是 28.00% 和 33.38% ，并且 MCF-7 房间的分别地是 31.58% 和 33.02% 。结论：对 survivin 的 siRNA 的表示向量能高效地并且明确地在 PC-2 和 MCF-7 房间堵住 survivin 表示。在 survivin 的规定下面，表示能压制 PC-2 和 MCF-7 房间的增长。Survivin RNAi 可以在人的癌症的基因治疗有潜在的价值。

Effects of Small Interfering RNATargeting Sphingosine Kinase-1 Gene on the Animal Model of Alzheimer's Disease

Summary： Alzheimer＇s disease （AD） is an age-related, progressive neurodegenerative disorder that occurs gradually and results in memory, behavior, and personality changes. Abnormal sphingolipid metabolism was reported in AD previously. This study aimed to investigate whether sphK1 could exacerbate the accumulation of amyloid protein （Aβ） and sharpen the learning and memory ability of the animal model of AD using siRNA interference. An adenovirus vector expressing small interfering RNA （siRNA） against the sphK1 gene （sphKl-siRNA） was designed, and the effects of sphKl-siRNA on the APP/PS1 mouse four weeks after treatment with sphKl-siRNA hippocampal injection were examined. SphK1 protein expression was confirmed by using Western blotting and ceramide content coupled with SIP secretion was evaluated by enzyme-linked immunosorbent assay （ELISA）. Aβ load was detected by immunohistochemical staining and ELISA. Morris water maze was adopted to test the learning and memory ability of the APP/PS 1 mice. A significant difference in the expression of sphK1 protein and mRNA was observed between the siRNA group and the control group. Aβ load in transfected mice was accelerated in vivo, with significant aggravation of the learn- ing and memory ability. The sphKl gene modulation in the All load and the learning and memory ability in the animal model of AD may be important for the treatment of AD.

Progress of Targeting Transforming Growth Factor-β1 Small Interfering RNA in Liver Fibrosis

Liver fibrosis is a common pathological consequence of a variety of chronic stimuli, including viral, autoimmune, drug-induced, cholestatic and metabolic diseases. Fibrosis is driven by a dynamic process involving increased synthesis of matrix components and a failure of physiological mechanisms of matrix turnover. Activation of hepatic stellate cells(HSCs) remains a central event in fibrosis. HSCs are the main source of extracellular matrix(ECM). Transforming growth factor-beta(TGF-β), which is the fibrogenic master cytokine, can induce the activation of HSCs to produce a large amount of ECM, and is capable of inducing apoptosis of liver cells. RNA interference(RNAi) is a novel gene disruption technology. Studies have shown that small interfering RNA(si RNA) targeting TGF-β1 may inhibit the activation and proliferation of HSCs, suppress ECM synthesis and block liver fibrosis. TGF-β1 si RNA-mediated gene silencing therapy provides a new avenue for liver fibrosis. This review summarizes recent progresses in research on HSCs, TGF-β1 and TGF-β1 si RNA in liver fibrosis.

Inhibition of HOXB7 Gene Expression in Melanoma Cells by Small Interfering RNA

Objective： HOXB7 gene is a kind of transcription regulator over-expressed in malignant melanoma （MM） cell lines. It can specifically up-regulate the expression of angiogenic factors and tumor growth factors such as bFGF, GROa, VEGF and induce angiogenesis in melanoma, resulting in the proliferation and metastasis of tumor cells. We designed and synthesized HOXB7 specific siRNA to study its interfering effect on the expressions of HOXB7 and bFGF genes in melanoma A375 cell line and the biologic characteristics of A375 cells. Methods： Three synthesized siRNA with different sequences were separately transfected into A375 cells by lipofecter 2000. The expression of HOXB7 and bFGF mRNA in transfected cells was detected by RT-PCR 24 and 48 hours after transduction. The expression of bFGF protein in the transfected cells were detected by flowcytometry 48 hours after transfection. MTT assay was used to analyze the cell proliferation rate of siRNA transfected cells. Based on the in vitro experiment results, one effective siRNA sequence was selected for the construction of in vivo siRNA expression vector. Then, a malignant melanoma animal model was established. The siRNA expression plasmid was injected into the tumor foci and its influence on the growth and angiogenesis of tumor was observed. Results： The mRNA expressions of both HOXB7 and bFGF genes in the A375 cells reduced significantly 24 and 48 hour after transfection of siRNA. Expression level of the protein of angiogenic factor bFGF induced by HOXB7 gene in siRNA transfected cells was significantly lower than that in control cells 48 hours after transduction. Cell proliferation was also suppressed in siRNA transfected cells. Two of the three siRNA strands showed prominent interference effect. The in vivo study indicated that the tumor size and the microvessel density in the tumor both reduced after injection of HOXB7siRNA plasmid. Conclusion： Down-regulation of HOXB7 gene expression can effectively reduce the expression of angiogenic factor bFGF and the proliferation of MM cells. Besides, the growth and angiogenesis of MM tumor were also inhibited.

Silencing invariant chain of DCs enhances Th1 response using small interfering RNA

RNA interference(RNAi),which causes the degradation of any RNA in a sequence specific manner,is a posttranscriptional gene silencing mechanism.Targeting the invariant chain(Ii)in DCs has been used as an approach to enhance antitumor immunity.It is demonstrated in this article that transfection of H-2(K)DCs with siRNA specific for Ii gene can significantly knock down Ii.When exposed to TNF-alpha,immature DCs transfected with Ii siRNA can differentiate into mature DCs without reducing viability or IL-12p70 production.Ii siRNA-treated H-2(K)DCs exhibited an increased allostimulatory capacity in a lymphocyte proliferation assay.Furthermore,Ii siRNA-transfected H-2(K)DCs enhanced Th1 responses by increasing IFN-gamma and decreasing IL-4 production,and much stronger cytotoxic activity was observed when DCs were co-transfected with Ii siRNA and an endogenous tumor antigen in vitro.Our findings indicate that silencing the Ii gene in DCs with siRNA may offer a potential approach to enhancing antitumor immunotherapy.

The influence of small interfering RNA on the expression of Survivin in human glioma cells

Objective This study aims to investigate the feasibility of knockdown of Survivin gene with small interfering RNA and to observe the apoptosis in gliomas which is influenced by siRNA. Methods Survivin specific siRNA oligonucleotides were designed and synthesized artificially. This siRNA

采用GFP标记筛选抑制多血清型口蹄疫病毒3C基因表达的siRNA

为筛选出可抑制多种血清型口蹄疫病毒(FMDV)的小干扰RNA(siRNA),本试验通过多血清型口蹄疫病毒序列比对与siRNA设计分析,筛选出潜在抗多血清型siRNA位点;通过体外合成A型、O型和Asia I型病毒部分基因序列,制备绿色荧光蛋白(GPF)基因融合表达载体;将化学合成的siRNA与融合表达载体共转染,通过GFP观察、Western blot和实时荧光定量反转录PCR(qRT-PCR)方法检验目标siRNA对融合基因的抑制效率。生物信息分析发现,多血清型口蹄疫病毒3C基因高度保守并存在潜在siRNA作用靶位,GFP-3C融合表达载体成功构建,与化学合成的siRNA1-3C共转染293T细胞,GFP观察发现,siRNA1-3C可有效抑制来源于A型、O型和Asia I型3C基因的GFP-3C荧光信号且持续时间达72 h,Western blot检测证实此结果。qRT-PCR检测发现,siRNA1-3C对3个GFP-3C融合基因转录水平抑制效率超85%,且作用可维持72 h。本试验利用GFP作为筛选标记成功筛选出1个作用于FMDV 3C基因的siRNA,为开发多血清型口蹄疫抑制剂提供参考依据。

siRNA非病毒载体递送用于肿瘤治疗的研究进展

近年来基于RNA干扰(RNA interference,RNAi)的基因治疗技术在肿瘤治疗方面引起广泛关注。在常规药物治疗无效的情况下,RNAi为癌症患者带来了新的希望。但是,由于小分子干扰RNA(small interfering RNA,siRNA)在体内存在易降解、难递送等问题,极大地限制了其临床转化潜力。纳米载体以其独特的尺寸效应和多样的修饰策略,能够介导高效、靶向的RNA递送,以实现其基因沉默。本文综述了RNAi在基因治疗中的作用机制以及体内递送siRNA的不同载体,介绍了载体体内递送siRNA的主要障碍和作用靶点,并比较了不同载体在siRNA递送中的优势和不足,为新载体的设计提供借鉴,推动RNA干扰疗法向临床的转化。

转染IGF2BP3基因siRNA和真核表达质粒的神经母细胞瘤细胞侵袭凋亡变化观察

目的观察转染胰岛素样生长因子2 mRNA结合蛋白3(IGF2BP3)基因siRNA和真核表达质粒的神经母细胞瘤(NB)细胞侵袭凋亡变化,以探讨IGF2BP3基因对NB细胞侵袭和凋亡的影响。方法选取NB细胞株IMR-32、SK-N-BE(2)、BE(2)-C、SH-SY-5Y,采用qRT-PCR检测IGF2BP3 mRNA、Western blotting法检测IGF2BP3蛋白、Transwell实验观察NB细胞的体外侵袭能力。根据上述实验结果,选择IGF2BP3表达水平最高的SK-N-BE(2)细胞及IGF2BP3表达水平最低的IMR-32细胞作为后续实验细胞。SK-N-BE(2)细胞转染针对IGF2BP3基因的小干扰RNA(siRNA)(SK-siIGF2BP3组),并设立细胞对照组(SK-Control组,只含有脂质体)和siRNA对照组(SK-siNC组,转染阴性对照序列)。IMR-32细胞转染IGF2BP3真核表达质粒(IMR-IGF2BP3组),并设立细胞对照组(IMR-Control组,只含有脂质体)和空载体对照组(IMR-Vector组,转染空载体)。转染成功后,采用qRT-PCR、Western blotting法和细胞免疫荧光染色法检测各组IGF2BP3 mRNA及蛋白,Transwell实验观察各组细胞侵袭能力,流式细胞术测算各组NB细胞凋亡率,Western blotting法检测各组细胞侵袭相关蛋白E-cadherin、N-cadherin、Vimentin。结果与SKControl组和SK-siNC组相比,SK-siIGF2BP3组IGF2BP3 mRNA、蛋白相对表达量降低,穿越Transwell小室膜细胞数减少,凋亡率升高(P均<0.05);与IMR-Control组和IMR-Vector组相比,IMR-IGF2BP3组IGF2BP3 mRNA、蛋白相对表达量升高,穿越Transwell小室膜细胞数增加,凋亡率降低(P均<0.05)。在SK-N-BE(2)细胞中,与SK-siNC组及SK-Control组比较,SK-siIGF2BP3组中N-cadherin、Vimentin蛋白相对表达量下降,E-cadherin蛋白相对表达量上升(P均<0.05);在IMR-32细胞中,与IMR-Vector组、IMR-Control组比较,IMR-IGF2BP3组N-cadherin和Vimentin蛋白相对表达量升高,E-cadherin蛋白相对表达量下降(P均<0.05)。结论转染IGF2BP3基因siRNA的NB细胞侵袭能力减弱、凋亡率增加,转染IGF2BP3真核表达质粒的NB细胞侵袭能力增强、凋亡率降低。

siRNA治疗在妇科肿瘤中应用的研究进展

妇科肿瘤在女性各类疾病中的发病率、死亡率均位居前列,且常规治疗后复发、耐药患者预后不佳。小干扰RNA(small interfering RNA,siRNA)能够高效沉默靶向基因,具有基因沉默效率高、合成简便且靶点广泛的优点,是一种有应用前景的治疗基因相关疾病的工具。但临床应用siRNA药物还需面对裸序列不稳定、体内传送效率低以及不可控的不良反应等问题。近年来,关于选择何种载体以实现体内递送siRNA药物以及如何选择合适的应用靶点,是针对siRNA治疗的研究焦点。综述近年来有关载体修饰siRNA药物在妇科肿瘤治疗中的应用,以及各类妇科肿瘤中siRNA重要的潜在应用靶点的研究进展。

Remodeling the tumor immune microenvironment via siRNA therapy for precision cancer treatment

How to effectively transform the pro-oncogenic tumor microenvironments(TME)surrounding a tumor into an anti-tumoral never fails to attract people to study.Small interfering RNA(siRNA)is considered one of the most noteworthy research directions that can regulate gene expression following a process known as RNA interference(RNAi).The research about siRNA delivery targeting tumor cells and TME has been on the rise in recent years.Using siRNA drugs to silence critical proteins in TME was one of the most efficient solutions.However,the manufacture of a siRNA delivery system faces three major obstacles,i.e.,appropriate cargo protection,accurately targeted delivery,and site-specific cargo release.In the following review,we summarized the pharmacological actions of siRNA drugs in remolding TME.In addition,the delivery strategies of siRNA drugs and combination therapy with siRNA drugs to remodel TME are thoroughly discussed.In the meanwhile,the most recent advancements in the development of all clinically investigated and commercialized siRNA delivery technologies are also presented.Ultimately,we propose that nanoparticle drug delivery siRNA may be the future research focus of oncogene therapy.This summary offers a thorough analysis and roadmap for general readers working in the field.

siRNA沉默CAPN1基因对人骨肉瘤细胞MG-63增殖、侵袭及Bcl-2和Bax表达的影响

目的探讨小干扰RNA(siRNA)沉默钙蛋白酶1(CAPN1)基因对人骨肉瘤细胞MG-63增殖、侵袭及B淋巴细胞瘤-2基因(Bcl-2)和Bcl-2相关X蛋白(Bax)表达的影响。方法将siRNA序列、CAPN1 siRNA序列分别转染MG-63细胞,分为CAPN1 siRNA组与siRNA组,以未转染的细胞作为对照组。采用q RT-PCR法检测细胞中CAPN1 mRNA表达水平;采用四唑盐比色法检测细胞增殖率;采用Transwell侵袭实验检测细胞侵袭率;采用Western blot法检测细胞中Bcl-2和Bax蛋白表达水平。结果CAPN1 siRNA组细胞CAPN1 mRNA表达水平、在培养12、24、36和48 h的增殖率、侵袭率、Bcl-2蛋白表达水平均低于对照组和siRNA组,而Bax蛋白表达水平高于对照组和siRNA组,差异均有统计学意义(均P<0.05);对照组和siRNA组细胞上述指标比较差异均无统计学意义(均P>0.05)。结论siRNA沉默CAPN1表达抑制了MG-63细胞增殖和侵袭能力,并促进其凋亡,其机制可能与调控Bcl-2和Bax蛋白表达有关。

Effect of siRNA interference on nerve growth factor in intervertebral disc inflammation rats

Objective:To investigate the inhibition effect of siRNA interference on NGF induced by inflammatory factor IL-6,and JUL—1 so as to provide novel targets for clinical treatment of discogenic low back pain.Methods:The intervertebral disc nucleus and annulus fibrosus cells of rats were separated-The cells were co-cultured with different concentrations(10 nmol/L,20nmol/L,50 nmol/L,100 nmol/L)of IL-6 and IL-1β.The NGF-siRNA was leaded into the cocultured cells with its import ability assessed by flow cytometry instrument tests,hefore and after which the NCF mRNA expression was detected by real-time Q-PCR and the NGF content was detected by ELISA.Results:Flow cytometry instrument test results showed that the NGFsiRNA cell conversion rate was 99.8%.Real-time Q-PCR detection results showed that compared with negative control group,the NGF mRNA expression of co-cultured cells treated by 10 nmol/L,20 nmol/L,50 nmol/L,100 nmol/L IL-6 and IL-1βwere respectively raised 3.4,3.7,4.7,3.7 times which were all significantly down-regulated after the import of NGF-siRNA.EILSA detection results showed that compared with negative control group,the NGF content of cocultured medium treated by 10 nmol/L,20 nmol/L,50 nmol/L,100 nmol/L I-L6 and IL-1βwere respectively raised 2.9,3.3,4.5,7.4 times which were all significantly decreased after the import of NGF-siRNA.Conclusions:These molecular biological results suggest that inflammatory factor IL-6 and IL-1βcould stimulate NCF on intervertebral disc cells in vitro culture model and its efficiency is concentration dependent,while siRNA interference can inhibit the stimulation effect of IL-6 and IL-1βon intervertebral disc cell,which provides a new targets for the clinical treatment of discogenic low back pain.

Small RNA Interference-mediated Gene Silencing of TREK-1 Potassium Channel in Cultured Astrocytes

This study was aimed to examine the effect of TREK-1 silencing on the function of astrocytes. Three 21-nucleotide small interfering RNA (siRNA) duplexes (siT1, siT2, siT3) targeting TREK-1 were constructed. Cy3-labeled dsRNA oligmers were used to determine the transfection efficiency in cultured astrocytes. TREK-1-specific siRNA duplexes (siT1, siT2, siT3) at the optimal concentration were transfected into cultured astrocytes, and the most efficient siRNA was identified by the method of immunocytochemical staining and Western blotting. The proliferation of astrocytes tranfected with TREK-1-targeting siRNA under hypoxia condition was measured by fluorescence-activated cell sorting (FACS). The results showed that TREK-1 was expressed in cultured astrocytes. The dsRNA oligmers targeting TREK-1 could be transfected efficiently in cultured astrocytes and down-regulate the expression of TREK-1 in astrocytes. Moreover, the down-regulation of TREK-1 in astrocytes contributed to the proliferation of astrocytes under hypoxia condition as determined by cell cycle analysis. It was concluded that siRNA is a powerful technique that can be used to knockdown the expression of TREK-1 in astrocytes, which helps further investigate the function of TREK-1 channel in astrocytes under physicological and pathological condition.