The Experts below are selected from a list of 16593 Experts worldwide ranked by ideXlab platform

Leaf Huang - One of the best experts on this subject based on the ideXlab platform.

  • a novel Cationic Lipid with intrinsic antitumor activity to facilitate gene therapy of trail dna
    Biomaterials, 2016
    Co-Authors: Lei Miao, Yi Zhao, Sara Musetti, Yuhua Wang, Leaf Huang
    Abstract:

    Metformin (dimethylbiguanide) has been found to be effective for the treatment of a wide range of cancer. Herein, a novel Lipid (1,2-di-(9Z-octadecenoyl)-3-biguanide-propane (DOBP)) was elaborately designed by utilizing biguanide as the Cationic head group. This novel Cationic Lipid was intended to act as a gene carrier with intrinsic antitumor activity. When compared with 1,2-di-(9Z-octadecenoyl)-3-trimethylammonium-propane (DOTAP), a commercially available Cationic Lipid with a similar structure, the blank liposomes consisting of DOBP showed much more potent antitumor effects than DOTAP in human lung tumor xenografts, following an antitumor mechanism similar to metformin. Given its Cationic head group, biguanide, DOBP could encapsulate TNF-related apoptosis-inducing ligand (TRAIL) plasmids into Lipid-Protamine-DNA (LPD) nanoparticles (NPs) for systemic gene delivery. DOBP-LPD-TRAIL NPs demonstrated distinct superiority in delaying tumor progression over DOTAP-LPD-TRAIL NPs, due to the intrinsic antitumor activity combined with TRAIL-induced apoptosis in the tumor. These results indicate that DOBP could be used as a versatile and promising Cationic Lipid for improving the therapeutic index of gene therapy in cancer treatment.

  • Enantiospecific adjuvant activity of Cationic Lipid DOTAP in cancer vaccine
    Cancer Immunology Immunotherapy, 2011
    Co-Authors: Elizabeth A. Vasievich, Weihsu Chen, Leaf Huang
    Abstract:

    Commercially available DOTAP is a racemic mixture of two enantiomers. The adjuvanticity of each isomer was examined using a peptide/Lipid complex as a therapeutic vaccine in an established murine cervical cancer model. This simple vaccine consists of a Cationic Lipid (DOTAP) and a major histocompatibility complex (MHC) class I–restricted epitope of the Human Papillomavirus (HPV) 16 protein E7. Dose-dependent tumor regression experiments have been completed for racemic DOTAP/E7, (R)-DOTAP/E7 and (S)-DOTAP/E7. Tumor-bearing mice treated with (R)-DOTAP/E7 complexes have shown tumor regression in a dose-dependent manner comparable to those mice treated with a racemic DOTAP with E7 peptide. These data are supported by IFN-γ production by CD8^+ splenocytes, in vivo cytotoxic T-lymphocytes (CTL) response, CD8^+ tumor-infiltrating lymphocytes (TIL), and IFN-γ production by CD8^+ TIL in (R)-DOTAP/E7-vaccinated mice. When (S)-DOTAP/E7 is delivered, tumor progression is delayed. While IFN-γ production is absent from CD8^+ splenocytes in mice vaccinated with (S)-DOTAP/E7, IFN-γ production by CD8^+ TIL is present, supporting our hypothesis that (S)-DOTAP has limited activity. Activation of bone marrow-derived dendritic cells by the enantiomeric formulations has also been evaluated, as well as cytokine production and toxicity with no considerable differences between the groups. The results show the DOTAP enantiomers act differently as adjuvants in vivo, with (R)-DOTAP being more effective at stimulating a CD8^+ anti-tumor response.

  • novel Cationic Lipid that delivers sirna and enhances therapeutic effect in lung cancer cells
    Molecular Pharmaceutics, 2009
    Co-Authors: Yunching Chen, Joyeeta Sen, Surendar Reddy Bathula, Qi Yang, Raffaella Fittipaldi, Leaf Huang
    Abstract:

    We have developed Lipid-polycation-DNA (LPD) nanoparticles containing DOTAP and targeted with polyethylene glycol (PEG) tethered with anisamide (AA) to specifically deliver siRNA to H460 human lung carcinoma cells which express the sigma receptor. A novel non-glycerol based Cationic Lipid which contains both a guanidinium and a lysine residue as the Cationic headgroup, i.e. DSGLA, downregulated pERK more efficiently in H460 cells than DOTAP. As demonstrated by using fluorescently labeled siRNA, LPD-PEG-AA prepared with DSGLA efficiently delivered siRNA to the cytoplasm of the H460 cells. Although the siRNA delivered by LPD-PEG-AA containing either DOTAP or DSGLA could effectively silence EGFR expression, a synergistic cell killing effect in promoting cellular apoptosis was only observed with DSGLA. The fluorescently labeled siRNA was efficiently delivered into the cytoplasm of H460 xenograft tumor by the LPD-PEG-AA containing either DOTAP or DSGLA 4 h after intravenous injection. Three daily injections (0.6 mg/kg) of siRNA formulated in the LPD-PEG-AA containing either DOTAP or DSGLA could effectively silence the epidermal growth factor receptor (EGFR) in the tumor, but the formulation containing DSGLA could induce more cellular apoptosis. A significant improvement in tumor growth inhibition was observed after dosing with LPD-PEG-AA containing DSGLA. Thus, DSGLA served as both a formulation component as well as a therapeutic agent which synergistically enhanced the activity of siRNA.

  • a simple but effective cancer vaccine consisting of an antigen and a Cationic Lipid
    Cancer Immunology Immunotherapy, 2008
    Co-Authors: Weihsu Chen, Weili Yan, Leaf Huang
    Abstract:

    Developing a cancer vaccine with a potent adjuvant, which is safe for human use, remains to be an unmet need. In this study, we developed a simple, safe, yet efficient, peptide-based therapeutic cancer vaccine, DOTAP/E7 complex, which comprises only two molecules: a DOTAP Cationic Lipid and a peptide antigen derived from E7 oncoprotein of human papillomavirus (HPV) type 16. The anti-cancer activity of DOTAP/E7 against existing HPV positive TC-1 tumor was compared to that of our previous LPD/E7 formulation, which contains bacterial DNA CpG motifs. Tumor-bearing mice showed significant tumor inhibition following a single vaccination of either formulation at the optimal Lipid dose, suggesting that DOTAP liposome alone can provide a potent adjuvant activity without plasmid DNA. E7 peptide formulated with DOTAP induced migration of activated dendritic cells (DC) to the draining lymph node (DLN) and efficiently generated functional antigen-specific CD8+ T lymphocyte responses. Accumulation of CD8+ tumor infiltrating T cells and apoptosis at tumor sites were observed after treatment with DOTAP/E7 complexes, which was also associated with a decreased amount of CD25(+)Foxp3(+) regulatory T cells in treated animals. Reactive oxygen species (ROS) induced by DOTAP Cationic Lipid in DLN revealed a plausible mechanism of the initial interaction between DC and DOTAP. An adequate amount of ROS generation was apparently required for the initiation of the vaccine mechanism; however, an overdose of DOTAP induced massive ROS production and apoptosis of DC in DLN, which led to diminished anti-cancer immunity. Overall, these results indicate that Cationic Lipid DOTAP alone serves as an efficient vaccine adjuvant for the induction of a therapeutic, antigen-specific anti-cancer activity.

  • lyophilization of Cationic Lipid protamine dna lpd complexes
    Journal of Pharmaceutical Sciences, 2000
    Co-Authors: Yadi Tan, Leaf Huang, Donna B Stolz, Simon C Watkins, Lawrence H Block
    Abstract:

    Cationic Lipid-based gene delivery systems have shown promise in transfecting cells both in vitro and in vivo. However, these systems tend to form aggregates in liquid formulation during storage, which has limited their clinical applications. As a result, lyophilization of these systems has recently become a subject of increasing interest. In this paper, lyophilization of LPD, a novel Cationic Lipid-based gene delivery system, was studied. Both particle size and transfection efficiency could be preserved in the presence of sufficient amount of appropriate lyoprotectant. A series of monosaccharides and disaccharides, including dextrose, galactose, mannose, lactose, maltose, sucrose and trehalose, were evaluated for their lyoprotective effect and disaccharides showed more superior protection to monosaccharides. The effect of different freezing protocols for lyophilization was also evaluated and no significant difference was found. However, for freeze-thawing, fast freezing caused less aggregation. Finally, nonlyophilized LPD and LPD lyophilized with 10% sucrose were stored at different temperatures and their stability was followed for eight weeks. Lyophilized LPD could be stored at room temperature without significant change in particle size or loss of transfection efficiency.

Jun Wang - One of the best experts on this subject based on the ideXlab platform.

  • Cationic Lipid assisted nanoparticles for delivery of mrna cancer vaccine
    Biomaterials Science, 2018
    Co-Authors: Yanan Fan, Yingli Luo, Qian Chen, Li Wang, Houbing Zhang, Song Shen, Jun Wang
    Abstract:

    Message RNA-based vaccines with prominent advantages such as facile production, no requirement for nuclear entry and high safety without the need for integration into host genome have been shown to be potent activators of the cytotoxic immune system. However, wider applications of mRNA-based therapeutics have been hindered because of their intrinsically high vulnerability to expressed nucleases and difficulty while entering antigen-presenting cells (APCs) directly. Here, we investigated the potential of Cationic Lipid-assisted nanoparticles (CLAN), which form a clinically translatable nucleic acid delivery system working as a carrier of an mRNA vaccine. We found that CLAN encapsulating mRNA encoding antigen could effectively stimulate the maturation of dendritic cells (DCs) and promote the activation and proliferation of antigen-specific T cells both in vitro and in vivo. Intravenous immunization of mice with CLAN containing mRNA encoding ovalbumin (OVA) provoked a strong OVA-specific T-cell response and slowed tumor growth in an aggressive E·G7-OVA lymphoma model. Collectively, CLAN proved to be a promising platform for mRNA vaccine delivery.

  • macrophage specific in vivo gene editing using Cationic Lipid assisted polymeric nanoparticles
    ACS Nano, 2018
    Co-Authors: Yingli Luo, Xianzhu Yang, Zhiting Cao, Jing Liu, Jilong Wang, Jun Wang
    Abstract:

    The CRISPR/Cas9 gene editing technology holds promise for the treatment of multiple diseases. However, the inability to perform specific gene editing in targeted tissues and cells, which may cause off-target effects, is one of the critical bottlenecks for therapeutic application of CRISPR/Cas9. Herein, macrophage-specific promoter-driven Cas9 expression plasmids (pM458 and pM330) were constructed and encapsulated in Cationic Lipid-assisted PEG-b-PLGA nanoparticles (CLAN). The obtained nanoparticles encapsulating the CRISPR/Cas9 plasmids were able to specifically express Cas9 in macrophages as well as their precursor monocytes both in vitro and in vivo. More importantly, after further encoding a guide RNA targeting Ntn1 (sgNtn1) into the plasmid, the resultant CLANpM330/sgNtn1 successfully disrupted the Ntn1 gene in macrophages and their precursor monocytes in vivo, which reduced expression of netrin-1 (encoded by Ntn1) and subsequently improved type 2 diabetes (T2D) symptoms. Meanwhile, the Ntn1 gene was ...

  • triple negative breast cancer therapy with cdk1 sirna delivered by Cationic Lipid assisted peg pla nanoparticles
    Journal of Controlled Release, 2014
    Co-Authors: Yang Liu, Shuang Dou, Chengqiong Mao, Song Shen, Yanhua Zhu, Zibin Tan, Jun Wang
    Abstract:

    There is no effective clinical therapy yet for triple-negative breast cancer (TNBC) without particular human epidermal growth factor receptor-2, estrogen and progesterone receptor expression. In this study, we report a molecularly targeted and synthetic lethality-based siRNA therapy for TNBC treatment, using Cationic Lipid assisted poly(ethylene glycol)-b-poly(d,l-lactide) (PEG-PLA) nanoparticles as the siRNA carrier. It is demonstrated that only in c-Myc overexpressed TNBC cells, while not in normal mammary epithelial cells, delivery of siRNA targeting cyclin-dependent kinase 1 (CDK1) with the nanoparticle carrier (NPsiCDK1) induces cell viability decreasing and cell apoptosis through RNAi-mediated CDK1 expression inhibition, indicating the synthetic lethality between c-Myc with CDK1 in TNBC cells. Moreover, systemic delivery of NPsiCDK1 is able to suppress tumor growth in mice bearing SUM149 and BT549 xenograft and cause no systemic toxicity or activate the innate immune response, suggesting the therapeutic promise with such nanoparticles carrying siCDK1 for c-Myc overexpressed triple negative breast cancer.

  • Cationic Lipid assisted polymeric nanoparticle mediated gata2 sirna delivery for synthetic lethal therapy of kras mutant non small cell lung carcinoma
    Molecular Pharmaceutics, 2014
    Co-Authors: Song Shen, Xianzhu Yang, Xiaojiao Du, Jun Wang
    Abstract:

    Synthetic lethal interaction provides a conceptual framework for the development of wiser cancer therapeutics. In this study, we exploited a therapeutic strategy based on the interaction between GATA binding protein 2 (GATA2) downregulation and the KRAS mutation status by delivering small interfering RNA targeting GATA2 (siGATA2) with Cationic Lipid-assisted polymeric nanoparticles for treatment of non-small-cell lung carcinoma (NSCLC) harboring oncogenic KRAS mutations. Nanoparticles carrying siGATA2 (NPsiGATA2) were effectively taken up by NSCLC cells and resulted in targeted gene suppression. NPsiGATA2 selectively inhibited cell proliferation and induced cell apoptosis in KRAS mutant NSCLC cells. However, this intervention was harmless to normal KRAS wild-type NSCLC cells and HL7702 hepatocytes, confirming the advantage of synthetic lethality-based therapy. Moreover, systemic delivery of NPsiGATA2 significantly inhibited tumor growth in the KRAS mutant A549 NSCLC xenograft murine model, suggesting the ...

  • single step assembly of Cationic Lipid polymer hybrid nanoparticles for systemic delivery of sirna
    ACS Nano, 2012
    Co-Authors: Xianzhu Yang, Shuang Dou, Yucai Wang, Hongyan Long, Menghua Xiong, Chengqiong Mao, Yandan Yao, Jun Wang
    Abstract:

    The clinical success of therapeutics of small interfering RNA (siRNA) is still hindered by its delivery systems. Cationic polymer or Lipid-based vehicles as the major delivery systems of siRNA cannot sufficiently satisfy siRNA therapeutic applications. It is hypothesized that Cationic Lipid-polymer hybrid nanoparticles may take advantage of both polymeric and Lipid-based nanoparticles for siRNA delivery, while diminishing the shortcomings of both. In this study, Cationic Lipid-polymer hybrid nanoparticles were prepared by a single-step nanoprecipitation of a Cationic Lipid (N,N-bis(2-hydroxyethyl)-N-methyl-N-(2-cholesteryloxycarbonyl aminoethyl) ammonium bromide, BHEM-Chol) and amphiphilic polymers for systemic delivery of siRNA. The formed hybrid nanoparticles comprised a hydrophobic polylactide core, a hydrophilic poly(ethylene glycol) shell, and a Cationic Lipid monolayer at the interface of the core and the shell. Such hybrid nanoparticles exhibited excellent stability in serum and showed significantly improved biocompatibility compared to that of pure BHEM-Chol particles. The hybrid nanoparticles were capable of delivering siRNA into BT474 cells and facilitated the escape of loaded siRNA from the endosome into the cytoplasm. The hybrid nanoparticles carrying polo-like kinase 1 (Plk1)-specific siRNA (siPlk1) remarkably and specifically downregulated expression of the oncogene Plk1 and induced cancer cell apoptosis both in vitro and in vivo and significantly suppressed tumor growth following systemic administration. We demonstrate that this system is stable, nontoxic, highly efficient, and easy to scale up, bringing the clinical application of siRNA therapy one important step closer to reality.

Xianzhu Yang - One of the best experts on this subject based on the ideXlab platform.

  • macrophage specific in vivo gene editing using Cationic Lipid assisted polymeric nanoparticles
    ACS Nano, 2018
    Co-Authors: Yingli Luo, Xianzhu Yang, Zhiting Cao, Jing Liu, Jilong Wang, Jun Wang
    Abstract:

    The CRISPR/Cas9 gene editing technology holds promise for the treatment of multiple diseases. However, the inability to perform specific gene editing in targeted tissues and cells, which may cause off-target effects, is one of the critical bottlenecks for therapeutic application of CRISPR/Cas9. Herein, macrophage-specific promoter-driven Cas9 expression plasmids (pM458 and pM330) were constructed and encapsulated in Cationic Lipid-assisted PEG-b-PLGA nanoparticles (CLAN). The obtained nanoparticles encapsulating the CRISPR/Cas9 plasmids were able to specifically express Cas9 in macrophages as well as their precursor monocytes both in vitro and in vivo. More importantly, after further encoding a guide RNA targeting Ntn1 (sgNtn1) into the plasmid, the resultant CLANpM330/sgNtn1 successfully disrupted the Ntn1 gene in macrophages and their precursor monocytes in vivo, which reduced expression of netrin-1 (encoded by Ntn1) and subsequently improved type 2 diabetes (T2D) symptoms. Meanwhile, the Ntn1 gene was ...

  • Cationic Lipid assisted polymeric nanoparticle mediated gata2 sirna delivery for synthetic lethal therapy of kras mutant non small cell lung carcinoma
    Molecular Pharmaceutics, 2014
    Co-Authors: Song Shen, Xianzhu Yang, Xiaojiao Du, Jun Wang
    Abstract:

    Synthetic lethal interaction provides a conceptual framework for the development of wiser cancer therapeutics. In this study, we exploited a therapeutic strategy based on the interaction between GATA binding protein 2 (GATA2) downregulation and the KRAS mutation status by delivering small interfering RNA targeting GATA2 (siGATA2) with Cationic Lipid-assisted polymeric nanoparticles for treatment of non-small-cell lung carcinoma (NSCLC) harboring oncogenic KRAS mutations. Nanoparticles carrying siGATA2 (NPsiGATA2) were effectively taken up by NSCLC cells and resulted in targeted gene suppression. NPsiGATA2 selectively inhibited cell proliferation and induced cell apoptosis in KRAS mutant NSCLC cells. However, this intervention was harmless to normal KRAS wild-type NSCLC cells and HL7702 hepatocytes, confirming the advantage of synthetic lethality-based therapy. Moreover, systemic delivery of NPsiGATA2 significantly inhibited tumor growth in the KRAS mutant A549 NSCLC xenograft murine model, suggesting the ...

  • single step assembly of Cationic Lipid polymer hybrid nanoparticles for systemic delivery of sirna
    ACS Nano, 2012
    Co-Authors: Xianzhu Yang, Shuang Dou, Yucai Wang, Hongyan Long, Menghua Xiong, Chengqiong Mao, Yandan Yao, Jun Wang
    Abstract:

    The clinical success of therapeutics of small interfering RNA (siRNA) is still hindered by its delivery systems. Cationic polymer or Lipid-based vehicles as the major delivery systems of siRNA cannot sufficiently satisfy siRNA therapeutic applications. It is hypothesized that Cationic Lipid-polymer hybrid nanoparticles may take advantage of both polymeric and Lipid-based nanoparticles for siRNA delivery, while diminishing the shortcomings of both. In this study, Cationic Lipid-polymer hybrid nanoparticles were prepared by a single-step nanoprecipitation of a Cationic Lipid (N,N-bis(2-hydroxyethyl)-N-methyl-N-(2-cholesteryloxycarbonyl aminoethyl) ammonium bromide, BHEM-Chol) and amphiphilic polymers for systemic delivery of siRNA. The formed hybrid nanoparticles comprised a hydrophobic polylactide core, a hydrophilic poly(ethylene glycol) shell, and a Cationic Lipid monolayer at the interface of the core and the shell. Such hybrid nanoparticles exhibited excellent stability in serum and showed significantly improved biocompatibility compared to that of pure BHEM-Chol particles. The hybrid nanoparticles were capable of delivering siRNA into BT474 cells and facilitated the escape of loaded siRNA from the endosome into the cytoplasm. The hybrid nanoparticles carrying polo-like kinase 1 (Plk1)-specific siRNA (siPlk1) remarkably and specifically downregulated expression of the oncogene Plk1 and induced cancer cell apoptosis both in vitro and in vivo and significantly suppressed tumor growth following systemic administration. We demonstrate that this system is stable, nontoxic, highly efficient, and easy to scale up, bringing the clinical application of siRNA therapy one important step closer to reality.

  • systemic delivery of sirna with Cationic Lipid assisted peg pla nanoparticles for cancer therapy
    Journal of Controlled Release, 2011
    Co-Authors: Xianzhu Yang, Hongxia Wang, Jun Wang
    Abstract:

    Abstract Delivery of small interfering RNA (siRNA) has been one of the major hurdles for the application of RNA interference in therapeutics. Here, we describe a Cationic Lipid assisted polymeric nanoparticle system with stealthy property for efficient siRNA encapsulation and delivery, which was fabricated with poly(ethylene glycol)- b -poly( d,l -lactide), siRNA and a Cationic Lipid, using a double emulsion-solvent evaporation technique. By incorporation of the Cationic Lipid, the encapsulation efficiency of siRNA into the nanoparticles could be above 90% and the siRNA loading weight ratio was up to 4.47%, while the diameter of the nanoparticles was around 170 to 200 nm. The siRNA retained its integrity within the nanoparticles, which were effectively internalized by cancer cells and escaped from the endosome, resulting in significant gene knockdown. This effect was demonstrated by significant down-regulation of luciferase expression in HepG2-luciferase cells which stably express luciferase, and suppression of polo-like kinase 1 (Plk1) expression in HepG2 cells, following delivery of specific siRNAs by the nanoparticles. Furthermore, the nanoparticles carrying siRNA targeting the Plk1 gene were found to induce remarkable apoptosis in both HepG2 and MDA-MB-435s cancer cells. Systemic delivery of specific siRNA by nanoparticles significantly inhibited luciferase expression in an orthotopic murine liver cancer model and suppressed tumor growth in a MDA-MB-435s murine xenograft model, suggesting its therapeutic promise in disease treatment.

Ronald K Scheule - One of the best experts on this subject based on the ideXlab platform.

  • endostatin gene transfection using a Cationic Lipid advantages of transfection before tumor cell inoculation and repeated transfection
    Cancer Gene Therapy, 2004
    Co-Authors: Motoki Yano, Yoshiaki Nakashima, Yoshihiro Kobayashi, Kotaro Mizuno, Akimitsu Konishi, Hidefumi Sasaki, Ichiro Fukai, Ronald K Scheule
    Abstract:

    Intravenous endostatin gene transfection results in tumor suppression in a murine pulmonary metastasis model. We transfected the endostatin gene at different times, in order to achieve an optimal protective effect. pST2-Endo encoding murine endostatin was injected in a complex with Cationic Lipid. Pulmonary metastases were caused by intravenous injection of murine fibrosarcoma cells. Mice were observed for 14 days following fibrosarcoma cell inoculation (FSI). In the study groups, the animals were transfected with pST2-Endo at three different times: 2 days before and 3 and 7 days after FSI. In the group transfected with pST2-Endo 2 days before FSI, the weights of the lungs and tumor-occupied area ratio were significantly less than in the other groups. Significant inhibition of tumor neovascularization was documented by means of CD31 immunohistochemistry. The effect of repeated endostatin transfection on survival after FSI was determined. Animals repeatedly transfected with the endostatin gene survived significantly longer than the groups treated with a single endostatin gene transfection. A stable endostatin-expressing fibrosarcoma transfectant was created and tested for migration and invasion. Compared with controls, endostatin expression reduced migration and invasion by 15%. It is concluded that endostation gene transfection before FSI and repeated transfection thereafter results in significant tumor suppression.

  • comprehensive analysis of the acute toxicities induced by systemic administration of Cationic Lipid plasmid dna complexes in mice
    Human Gene Therapy, 2000
    Co-Authors: Jennifer D Tousignant, Amy L Gates, Laurie Ingram, Carrie Johnson, Jennifer B Nietupski, Seng H Cheng, Simon J Eastman, Ronald K Scheule
    Abstract:

    A major limitation associated with systemic administration of Cationic Lipid:plasmid DNA (pDNA) complexes is the vector toxicity at the doses necessary to produce therapeutically relevant levels of transgene expression. Systematic evaluation of these toxicities has revealed that mice injected intravenously with Cationic Lipid:pDNA complexes develop significant, dose-dependent hematologic and serologic changes typified by profound leukopenia, thrombocytopenia, and elevated levels of serum transaminases indicative of hepatocellular necrosis. Vector administration also induced a potent inflammatory response characterized by complement activation and the induction of the cytokines IFN-γ, TNF-α, IL-6, and IL-12. These toxicities were found to be transient, resolving with different kinetics to pretreatment levels by 14 days posttreatment. The toxic syndrome observed was independent of the Cationic Lipid:pDNA ratio, the Cationic Lipid species, and the level of transgene expression attained. Mechanistic studies d...

  • contribution of plasmid dna to inflammation in the lung after administration of Cationic Lipid pdna complexes
    Human Gene Therapy, 1999
    Co-Authors: Nelson S Yew, Ronald K Scheule, John Marshall, Kathryn X Wang, Malgorzata Przybylska, Rebecca G Bagley, Margaret Stedman, Seng H Cheng
    Abstract:

    Cationic Lipid-mediated gene transfer to the mouse lung induces a dose-dependent inflammatory response that is characterized by an influx of leukocytes and elevated levels of the cytokines interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-alpha), and interferon gamma (IFN-gamma). We have examined the contribution of plasmid DNA (pDNA) to this observed toxicity, specifically the role of unmethylated CpG dinucleotides, which have been previously shown to be immunostimulatory. We report here that complexes of Cationic Lipid GL-67 and unmethylated pDNA (pCF1-CAT) instilled into the lungs of BALB/c mice induced highly elevated levels of the cytokines TNF-alpha, IFN-gamma, IL-6, and IL-12 in the bronchoalveolar lavage fluids (BALF). In contrast, BALF of animals administered either GL-67 alone or GL-67 complexed with Sss I-methylated pDNA contained low levels of these cytokines. Similar results were observed using a plasmid (pCF1-null) that does not express a transgene, demonstrating that expression of chlo...

  • Cationic Lipid formulations for intracellular gene delivery of cystic fibrosis transmembrane conductance regulator to airway epithelia
    Methods in Enzymology, 1998
    Co-Authors: S H Cheng, Ronald K Scheule, John Marshall, Alan E Smith
    Abstract:

    Publisher Summary This chapter describes Cationic Lipid formulations for intracellular gene delivery of cystic fibrosis transmembrane conductance regulator to airway epithelia. Much progress has been made in the recent past in terms of developing new Cationic Lipid structures with increased potency and activity. The understanding of Cationic Lipid structure–activity relationships and cellular barriers to gene delivery increases potent Cationic Lipid structures. In the absence of a detailed understanding of the mechanism of Cationic Lipid-mediated gene delivery, an extensive and essentially empirical optimization of the formulations is necessary. Gene transfer vectors that are being developed include recombinant viral vectors and nonviral, synthetic self-assembling systems, such as those formed using polyCationic molecular conjugates and Cationic Lipids. Synthetic Cationic Lipids are used successfully for the delivery of a number of genes to a variety of different cell types in vitro and in vivo .

  • basis of pulmonary toxicity associated with Cationic Lipid mediated gene transfer to the mammalian lung
    Human Gene Therapy, 1997
    Co-Authors: Ronald K Scheule, John Marshall, Kathryn X Wang, Rebecca G Bagley, Judith A St George, Johanne Kaplan, Geoffrey Y Akita, Edward R Lee, David J Harris, Canwen Jiang
    Abstract:

    Studies have indicated that although abundant levels of transgene expression could be achieved in the lungs of mice instilled with Cationic Lipid:pDNA complexes, the efficiency of gene transfer is low. As a consequence, a relatively large amount of the complex will need to be administered to the human lungs to achieve therapeutic efficacy for indications such as cystic fibrosis. Because all Cationic Lipids exhibit some level of cytotoxicity in vitro, we assessed the safety profile of one such Cationic Lipid, GL-67, following administration into the lungs of BALB/c mice. Dose-dependent pulmonary inflammation was observed that was characterized by infiltrates of neutrophils, and, to a lesser extent, macrophages and lymphocytes. The lesions in the lung were multifocal in nature and were manifested primarily at the junction of the terminal bronchioles and alveolar ducts. The degree of inflammation abated with time and there were no apparent permanent fibrotic lesions, even in animals that were treated at the highest doses. Analysis of the individual components of the complex revealed that the pulmonary inflammation was primarily Cationic Lipid-mediated with a minor contribution from the neutral co-Lipid DOPE. Associated with the lesions in the lungs were elevated levels of the pro-inflammatory cytokines interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and interferon-gamma (IFN-gamma) that peaked at days 1-2 post-instillation but resolved to normal limits by day 14. Total cell counts, primarily of neutrophils, were also significantly elevated in the bronchoalveolar lavage fluids of GL-67:pDNA-treated mice between days 1 and 3 but returned to normal limits by day 14. No specific immune responses were detected against the Cationic Lipid or plasmid DNA in mice that had been either instilled or immunized with the individual components or complex, nor was there any evidence of complement activation. These studies indicate that a significant improvement in the potency of Cationic Lipid:pDNA formulations is desirable to minimize the toxicity associated with Cationic Lipids.

Robert C Macdonald - One of the best experts on this subject based on the ideXlab platform.

  • synergy in lipofection by Cationic Lipid mixtures superior activity at the gel liquid crystalline phase transition
    Journal of Physical Chemistry B, 2007
    Co-Authors: Rumiana Koynova, Li Wang, Robert C Macdonald
    Abstract:

    Some mixtures of two Cationic Lipids including phosphoLipid compounds (O-ethylphosphatidylcholines) as well as common, commercially available Cationic Lipids, such as dimethylammonium bromides and trimethylammonium propanes, deliver therapeutic DNA considerably more efficiently than do the separate molecules. In an effort to rationalize this widespread “mixture synergism”, we examined the phase behavior of the Cationic Lipid mixtures and constructed their binary phase diagrams. Among a group of more than 50 formulations, the compositions with maximum delivery activity resided unambiguously in the solid−liquid crystalline two-phase region at physiological temperature. Thus, the transfection efficacy of formulations exhibiting solid−liquid crystalline phase coexistence is more than 5 times higher than that of formulations in the gel (solid) phase and over twice that of liquid crystalline formulations; phase coexistence occurring at physiological temperature thus appears to contribute significantly to mixtur...

  • synergy in lipofection by Cationic Lipid mixtures superior activity at the gel liquid crystalline phase transition
    Journal of Physical Chemistry B, 2007
    Co-Authors: Rumiana Koynova, Li Wang, Robert C Macdonald
    Abstract:

    Some mixtures of two Cationic Lipids including phosphoLipid compounds (O-ethylphosphatidylcholines) as well as common, commercially available Cationic Lipids, such as dimethylammonium bromides and trimethylammonium propanes, deliver therapeutic DNA considerably more efficiently than do the separate molecules. In an effort to rationalize this widespread "mixture synergism", we examined the phase behavior of the Cationic Lipid mixtures and constructed their binary phase diagrams. Among a group of more than 50 formulations, the compositions with maximum delivery activity resided unambiguously in the solid-liquid crystalline two-phase region at physiological temperature. Thus, the transfection efficacy of formulations exhibiting solid-liquid crystalline phase coexistence is more than 5 times higher than that of formulations in the gel (solid) phase and over twice that of liquid crystalline formulations; phase coexistence occurring at physiological temperature thus appears to contribute significantly to mixture synergism. This relationship between delivery activity and physical property can be rationalized on the basis of the known consequences of Lipid-phase transitions, namely, the accumulation of defects and increased disorder at solid-liquid crystalline phase boundaries. Packing defects at the borders of coexisting solid and liquid crystalline domains, as well as large local density fluctuations, could be responsible for the enhanced fusogenicity of mixtures. This study leads to the important conclusion that manipulating the composition of the Lipid carriers so that their phase transition takes place at physiological temperature can enhance their delivery efficacy.