Effects of Cell Cycle Status on the Efficiency of Liposome-mediated Gene Transfection in Mouse Fetal Fibroblasts

Serum starvation is as efficient as roscovitine on the cycle synchronization in G0/G1 of red-rumped agouti fibroblasts

Fibroblast cycle synchronization in G0/G1 is an essential step for nuclear reprogramming by cloning or induced cells to pluripotency. Considering the diversity among rodents and the ecological and scientific importance of these animals, we compared the contact inhibition, serum starvation, and 10 µM of roscovitine as methods of synchronization of red-rumped agouti fibroblasts. The effects of each protocol were evaluated on the percentage of cycle phase, morphology, viability, and apoptosis levels. The results showed that culturing the cells to serum starvation for 24 h (75.9%), 48 h (81.6%), 72 h (86.2%), 96 h (84.0%), and 120 h (83.7%) yielded a significantly higher percentage of cells arrested in the G0/G1 (P < 0.05) phase than cells not subjected to any cell cycle synchronization method (31.4%). Also, this effect was not different between the times of 48 and 120 h (P > 0.05). A similar response was observed for cells cultured with roscovitine for 12 h (86.9%), 24 h (74.8%), and 48 h (81.7%), with a higher percentage of synchronized cells in G0/G1 compared to cells not submitted to any synchronization treatment (52.2%). Nevertheless, this effect was best evidenced at 12 h (P < 0.05). Also, the contact inhibition for 24-120 h could not synchronize cells in G0/G1, with values ranging from 70.9 to 77.9% (P > 0.05). Moreover, no difference was observed for morphology, viability, and apoptosis levels in any synchronization method (P > 0.05). Therefore, serum starvation is as efficient as roscovitine on cycle synchronization in G0/G1 of red-rumped agouti fibroblasts.

Exploiting endocytosis for transfection of mRNA for cytoplasmatic delivery using cationic gold nanoparticles

Introduction

Gene therapy holds promise to cure various diseases at the fundamental level. For that, efficient carriers are needed for successful gene delivery. Synthetic 'non-viral' vectors, as cationic polymers, are quickly gaining popularity as efficient vectors for transmitting genes. However, they suffer from high toxicity associated with the permeation and poration of the cell membrane. This toxic aspect can be eliminated by nanoconjugation. Still, results suggest that optimising the oligonucleotide complexation, ultimately determined by the size and charge of the nanovector, is not the only barrier to efficient gene delivery.

Methods

We herein develop a comprehensive nanovector catalogue comprising different sizes of Au NPs functionalized with two different cationic molecules and further loaded with mRNA for its delivery inside the cell.

Results and Discussion

Tested nanovectors showed safe and sustained transfection efficiencies over 7 days, where 50 nm Au NPs displayed the highest transfection rates. Remarkably, protein expression was increased when nanovector transfection was performed combined with chloroquine. Cytotoxicity and risk assessment demonstrated that nanovectors are safe, ascribed to lesser cellular damage due to their internalization and delivery via endocytosis. Obtained results may pave the way to design advanced and efficient gene therapies for safely transferring oligonucleotides.

Liposome-Mediated Gene Transfer in Differentiated HepaRG™ Cells: Expression of Liver Specific Functions and Application to the Cytochrome P450 2D6 Expression

The goal of this study was to establish a procedure for gene delivery mediated by cationic liposomes in quiescent differentiated HepaRG™ human hepatoma cells. We first identified several cationic lipids promoting efficient gene transfer with low toxicity in actively dividing HepG2, HuH7, BC2 and progenitor HepaRG™ human hepatoma cells. The lipophosphoramidate Syn1-based nanovector, which allowed the highest transfection efficiencies of progenitor HepaRG™ cells, was next used to transfect differentiated HepaRG™ cells. Lipofection of these cells using Syn1-based liposome was poorly efficient most likely because the differentiated HepaRG™ cells are highly quiescent. Thus, we engineered the differentiated HepaRG™ Mitogenic medium supplement (ADD1001) that triggered robust proliferation of differentiated cells. Importantly, we characterized the phenotypical changes occurring during proliferation of differentiated HepaRG™ cells and demonstrated that mitogenic stimulation induced a partial and transient decrease in the expression levels of some liver specific functions followed by a fast recovery of the full differentiation status upon removal of the mitogens. Taking advantage of the proliferation of HepaRG™ cells, we defined lipofection conditions using Syn1-based liposomes allowing transient expression of the cytochrome P450 2D6, a phase I enzyme poorly expressed in HepaRG cells, which opens new means for drug metabolism studies in HepaRG™ cells.

A Focus on "Bio" in Bio-Nanoscience: The Impact of Biological Factors on Nanomaterial Interactions

Bio-nanoscience research encompasses studies on the interactions of nanomaterials with biological structures or what is commonly referred to as the biointerface. Fundamental studies on the influence of nanomaterial properties, including size, shape, composition, and charge, on the interaction with the biointerface have been central in bio-nanoscience to assess nanomaterial efficacy and safety for a range of biomedical applications. However, the state of the cells, tissues, or biological models can also influence the behavior of nanomaterials at the biointerface and their intracellular processing. Focusing on the "bio" in bio-nano, this review discusses the impact of biological properties at the cellular, tissue, and whole organism level that influences nanomaterial behavior, including cell type, cell cycle, tumor physiology, and disease states. Understanding how the biological factors can be addressed or exploited to enhance nanomaterial accumulation and uptake can guide the design of better and suitable models to improve the outcomes of materials in nanomedicine.

A Comparative Approach of Cellular Reprogramming in the Rodentia Order

Cellular reprogramming mainly involves induction of reactivation of genes responsible for nuclear plasticity, a process that can be performed in vitro through production of cloned embryos by somatic cell nuclear transfer or by induction of cells into the pluripotent state through exogenous transcription factor expression. While these techniques are already well known and utilized in mice and rats, their application in other rodent species would be greatly beneficial, especially for conservation purposes. Within the diverse Rodentia order, wild species stand out as they play an important role in balancing the ecosystem by facilitating seed diversion, soil aeration, and consequently, reforestation. Many of these species are currently approaching extinction, and application of techniques, such as nuclear reprogramming, aimed at species conservation and multiplication and to produce stem cells is of interest. Thus, in this review, we aimed to present the evolution and success of nuclear reprogramming, mainly highlighting its potential application for the conservation of wild rodents.

Quantitative Evaluation of Myostatin Gene in Stably Transfected Caprine Fibroblast Cells by Anti-Myostatin shRNA

Skeletal muscle is the major component of lean tissue that is used for consumption, and myostatin is a negative regulator of skeletal muscle growth. Downregulation of this gene therefore offers a strategy for developing superior animals with enhanced muscle growth. Knockdown of myostatin was achieved by RNA interference technology. The anti-myostatin shRNA were designed and stably transfected in caprine fibroblast cells. The reduced expression of target gene was achieved and measured in clonal fibroblast cells by real-time PCR. Two single-cell clones induced significant decrease of myostatin gene expression by 73.96 and 72.66 %, respectively (P < 0.05). To ensure the appropriate growth of transfected cell, seven media were tested. The best suited media was used for transfected fibroblast cell proliferation. The findings suggest that shRNA provides a novel potential tool for gene knockdown and these stably transfected cells can be used as the donor cells for animal cloning.

New developments and opportunities in oral mucosal drug delivery for local and systemic disease

The oral mucosa's accessibility, excellent blood supply, by-pass of hepatic first-pass metabolism, rapid repair and permeability profile make it an attractive site for local and systemic drug delivery. Technological advances in mucoadhesives, sustained drug release, permeability enhancers and drug delivery vectors are increasing the efficient delivery of drugs to treat oral and systemic diseases. When treating oral diseases, these advances result in enhanced therapeutic efficacy, reduced drug wastage and the prospect of using biological agents such as genes, peptides and antibodies. These technologies are also increasing the repertoire of drugs that can be delivered across the oral mucosa to treat systemic diseases. Trans-mucosal delivery is now a favoured route for non-parenteral administration of emergency drugs and agents where a rapid onset of action is required. Furthermore, advances in drug delivery technology are bringing forward the likelihood of transmucosal systemic delivery of biological agents.

Transfection efficiency for size-separated cells synchronized in cell cycle by microfluidic device

Non-viral system generally demonstrates less efficacious in transgene delivery than viral system; however it represents a safer alternative to viral system. In this study, transfection efficiency for human hepatocellular liver carcinoma cells synchronized in cell cycle at G0/G1 phase, which was sorted in size with a microfluidic device based on hydrodynamic filtration, was investigated by using a reverse transfection method. The synchronized cells were recovered at the yield of 80% from the micro-channel, and green fluorescent protein gene encoding plasmid mixed with lipofectoamine was transfected. The transfection efficiency of the cells at G0/G1 phase was 1.8 times higher than non-synchronized cells. The manipulation of cell cycle status could increase transfection efficiency in non-viral system, indicating size-based cell cycle synchronization is a powerful tool as a noninvasive method for bioscience and biotechnology.

Serum starvation improves transient transfection efficiency in differentiating embryonic stem cells

Control of genetic expression is a critical issue in the field of stem cell biology, where determining a cell fate or reprogramming adult somatic cells into pluripotent cells has become a common experimental practice. In turn, for these cells to have therapeutic clinical potential, techniques for controlling gene expression are needed that minimizes or eliminates the risk of oncogenesis and mutagenesis. Possible routes for achieving this outcome could come in the form of a transient nonviral gene delivery system. In this study, we improved the efficiency of transient gene delivery to differentiating murine embryonic stem (ES) cells via serum starvation for 3 days before transfection. The transient expression of a constitutively-controlled plasmid increased from ∼50% (replated control) to ∼83% when transfected after 3 days of serum starvation but decreased to ∼28% when transfected after 3 days in normal high serum-containing media. When probed with a liver-specific reporter, Cyp7A1, expression increased from ∼1.4% (replated control) to ∼3.7% when transfected after 3 days of serum starvation but decreased to ∼0.7% when transfected after 3 days in high serum-containing media. Cy3-tagged oligonucleotides were used to rapidly quantify DNA uptake and predict ultimate transfection efficiency. This study suggests that modifications in media serum levels before transfection can have a profound effect on improving nonviral gene delivery.

Chromatin configurations in the germinal vesicle of mammalian oocytes

In all the studied mammalian species, chromatin in the germinal vesicle (GV) is initially decondensed with the nucleolus not surrounded by heterochromatin (the NSN configuration). During oocyte growth, the GV chromatin condenses into perinucleolar rings (the SN configuration) or other corresponding configurations with or without the perinucleolar rings, depending on species. During oocyte maturation, the GV chromatin is synchronized in a less condensed state before germinal vesicle breakdown (GVBD) in species that has been minutely studied. Oocytes may also take on a SN/corresponding configuration during early atresia, but they undergo GVBD at the advanced stage of atresia. As not all the species show the SN configuration while in all the species, gene transcription always stops at the late stage of oocyte growth, it is suggested that not the formation of perinucleolar rings but a thorough condensation of GV chromatin is essential for transcriptional repression. The GV chromatin configuration is highly correlated with oocyte competence; oocytes must end the NSN configuration before they gain the full meiotic competence, and they must take on the SN/corresponding configurations and stop gene transcription before they acquire the competence for early embryonic development. While factors inhibiting follicle atresia tend to synchronize oocytes in a chromatin configuration toward maturation, factors inducing follicle atresia tend to synchronize oocytes in a chromatin configuration reminiscent of early atresia. Furthermore, although condensation of GV chromatin is associated with transcriptional repression, both processes may not be associated with histone deacetylation during oocyte growth.

Full term development of normal mice after transfer of IVF embryos derived from oocytes stored at room temperature for 1 day

Early studies have shown that some mouse cumulus–oocyte complexes (COCs) stored at room temperature for 24 h still retained full developmental potential. In this study, we stored denuded mouse oocytes (DOs) at room temperature (25 °C) for 24 h and activated these oocytes with 10 mM SrCl2 or fertilized the oocytes by IVF. We found that nearly half of the DOs stored at room temperature for 1 day can be fertilized normally by IVF and that two foster mothers gave birth to seven pups. Embryos from stored oocytes were cultured in CZB medium with or without 1 μg/ml 17β-estradiol (E2). The numbers of embryo that developed to morula/blastocyst stage after parthenogenetic activation and IVF were significantly increased when E2 was added to the culture (p < 0.05). These results suggest that E2 might improve mouse embryo development in vitro. The birth of seven agouti pups and their healthy growth indicated that the storage of DOs at room temperature for 1 day may be a practical procedure for mammalian reproduction.

Germinal vesicle chromatin configurations of bovine oocytes

A common feature in the configuration of germinal vesicle (GV) chromatin in most species is that diffuse chromatin condenses into a perinucleolar ring during follicular growth; however, no such ring was observed in goat oocytes. Reports on whether bovine GV chromatin condenses into a perinucleolar ring are controversial. Besides, it is not known whether the perinucleolar ring in an oocyte represents a step toward final maturation or atresia. Changes in GV chromatin configurations during growth and maturation of bovine oocytes were studied using a new method that allows a clearer visualization of both the nucleolus and the chromatin after Hoechst and chromomycin A(3) staining. On the basis of the degree of condensation and distribution, the GV chromatin of bovine oocytes were classified into five configurations: NSN with diffuse chromatin in the whole nuclear area, N with condensed netlike chromatin, C with clumped chromatin, SN with clumped chromatin surrounding the nucleoli, and F with floccular chromatin near the nucleoli and near the nuclear envelope. Most of the oocytes were at the NSN stage in the <1.4-mm follicles, but the NSN pattern disappeared completely in follicles larger than 1.5mm. The SN pattern began to emerge in 1.5-mm follicles, and the number of SN oocytes increased while the number of oocytes with N and C configurations decreased with follicular growth. During maturation in vivo, while the number of N, C, and SN oocytes decreased, that of the F oocytes increased and reached maximum at 51h post prostaglandin injection. After that, the number of F oocytes decreased significantly because of germinal vesicle breakdown (GVBD). During maturation in vitro, GV chromatin configurations changed in a similar manner as during maturation in vivo. Fewer oocytes were at N, C, and SN stages, but more were at F and GVBD stages in the atretic than in the healthy follicles. Serum starvation slowed the F-GVBD transition of the in vitro maturing oocytes. More oocytes were of the SN or C configuration when ovaries were transported at 45-40 degrees C than at 35-30 degrees C. Most of the heated oocytes were blocked at the SN stage during in vitro maturation. It is concluded that (i) bovine GV chromatin condenses into a perinucleolar ring during follicular growth; (ii) bovine oocytes were synchronized at the F stage before GVBD; (iii) oocyte GV chromatin configurations were affected by serum starvation, high temperature, and follicular atresia.