title: Creation of an In vivo cytosensor using engineered mesangial cells. Automatic sensing of glomerular inflammation controls transgene activity.
abstract: Automatic control over exogenous gene expression in response to the activity of disease is a crucial hurdle for gene transfer-based therapies. Towards achieving this goal, we created a "cytosensor" that perceives local inflammatory states and subsequently regulates foreign gene expression. alpha-Smooth muscle actin is known to be expressed in glomerular mesangial cells exclusively in pathologic situations. CArG box element, the crucial regulatory sequence of the alpha-smooth muscle actin promoter, was used as a sensor for glomerular inflammation. Rat mesangial cells were stably transfected with an expression plasmid that introduces a beta-galactosidase gene under the control of CArG box elements. In vitro, the established cells expressed beta-galactosidase exclusively after stimulation with serum. To examine whether the cells are able to automatically control transgene activity in vivo, serum-stimulated or unstimulated cells were transferred into normal rat glomeruli or glomeruli subjected to anti-Thy 1 glomerulonephritis. When stimulated cells were transferred into the normal glomeruli, beta-galactosidase expression was switched off in vivo within 3 d. In contrast, when unstimulated cells were transferred into the nephritic glomeruli, transgene expression was substantially induced. These data indicate the feasibility of using the CArG box element as a molecular sensor for glomerular injury. In the context of advanced forms of gene therapy, this approach provides a novel concept for automatic regulation of local transgene expression where the transgene is required to be activated during inflammation and deactivated when the inflammation has subsided.
authors.affiliation: Glomerular Bioengineering Unit, Department of Medicine, University College London Medical School, The Rayne Institute, London WC1E 6JJ, United Kingdom. m.kitamura@medicine.ucl.ac.uk
authors.forename: M
authors.initials: M
authors.lastname: Kitamura
authors.forename: H
authors.initials: H
authors.lastname: Kawachi
mesh_terms: D000199:Actins / Q000235:genetics; D000818:Animals; D015374:Biosensing Techniques; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation; D005920:Glomerular Mesangium / Q000201:enzymology*; D005921:Glomerulonephritis / Q000139:chemically induced / Q000378:metabolism; D051381:Rats; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D013997:Time Factors; D019076:Transgenes / Q000502:physiology*; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D000199:Actins; D017077:Culture Media, Conditioned; D001616:beta-Galactosidase