Glucocorticoid Cell Priming Enhances Transfection Outcomes in Adult Human Mesenchymal Stem Cells.

Human mesenchymal stem cells (hMSCs) are one of the most widely researched stem cell types with broad applications from basic research to therapeutics, the majority of which require introduction of exogenous DNA. However, safety and scalability issues hinder viral delivery, while poor efficiency hinders nonviral gene delivery, particularly to hMSCs. Here, we present the use of a pharmacologic agent (glucocorticoid) to overcome barriers to hMSC DNA transfer to enhance transfection using three common nonviral vectors.

Temporal endogenous gene expression profiles in response to polymer-mediated transfection and profile comparison to lipid-mediated transfection.

Background: Design of efficient nonviral gene delivery systems is limited by the rudimentary understanding of specific molecules that facilitate transfection.

Methods: Polyplexes using 25-kDa polyethylenimine (PEI) and plasmid-encoding green fluorescent protein (GFP) were delivered to HEK 293T cells. After treating cells with polyplexes, microarrays were used to identify endogenous genes differentially expressed between treated and untreated cells (2 h of exposure) or between flow-separated transfected cells (GFP+) and treated, untransfected cells (GFP-) at 8, 16 and 24 h after lipoplex treatment.

Temporal endogenous gene expression profiles in response to lipid-mediated transfection.

Background: Design of efficient nonviral gene delivery systems is limited as a result of the rudimentary understanding of the specific molecules and processes that facilitate DNA transfer.

Methods: Lipoplexes formed with Lipofectamine 2000 (LF2000) and plasmid-encoding green fluorescent protein (GFP) were delivered to the HEK 293T cell line. After treating cells with lipoplexes, HG-U133 Affymetrix microarrays were used to identify endogenous genes differentially expressed between treated and untreated cells (2 h exposure) or between flow-separated transfected cells (GFP+) and treated, untransfected cells (GFP-) at 8, 16 and 24 h after lipoplex treatment.

In vitro development of preimplantation porcine embryos using alginate hydrogels as a three-dimensional extracellular matrix.

Between Days 10 and 12 of gestation, porcine embryos undergo a dramatic morphological change, known as elongation, with a corresponding increase in oestrogen production that triggers maternal recognition of pregnancy. Elongation deficiencies contribute to embryonic loss, but exact mechanisms of elongation are poorly understood due to the lack of an effective in vitro culture system. Our objective was to use alginate hydrogels as three-dimensional scaffolds that can mechanically support the in vitro development of preimplantation porcine embryos.

Network analysis of endogenous gene expression profiles after polyethyleneimine-mediated DNA delivery.

Background: DNA delivery systems, which transport exogenous DNA to cells, have applications that include gene therapy, tissue engineering and medical devices. Although the cationic nonviral DNA carrier polyethyleneimine (PEI) has been widely studied, the molecular factors and pathways underlying PEI-mediated DNA transfer remain largely unknown, preventing the design of more efficient delivery systems.

Methods: HEK 293 T cells were treated with polyplexes formed with PEI and pEGFPLuc encoding for green fluorescent protein (GFP).

Microarray analysis of gene expression profiles in cells transfected with nonviral vectors.

Inefficient gene delivery is a critical factor limiting the use of nonviral methods in therapeutic applications including gene therapy and tissue engineering. There have been few efforts to understand or engineer the molecular signaling pathways that dictate the efficacy of gene transfer. Microarray analysis was used to determine endogenous gene expression profiles modulated during nonviral gene transfer.

MR elastography monitoring of tissue-engineered constructs.

The objective of tissue engineering (TE) is to create functional replacements for various tissues; the mechanical properties of these engineered constructs are critical to their function. Several techniques have been developed for the measurement of the mechanical properties of tissues and organs; however, current methods are destructive. The field of TE will benefit immensely if biomechanical models developed by these techniques could be combined with existing imaging modalities to enable noninvasive, dynamic assessment of mechanical properties during tissue growth.