TGF-beta1-driven fibrosis in diabetic glomerulosclerosis is mediated via the TGF-beta1 cell surface receptor (TbetaR) complex. TGF-beta induces its own synthesis and amplifies its effects via an intensely prosclerotic autoinduction cascade. Antisense therapy antagonizing the TbetaR subtype II can interrupt this fibrogenic sequence of events and thus may slow the development of glomerulosclerosis. In this regard, the investigators have developed an antisense sequence, which recognizes the TbetaR-II and inhibits autoinduction. However, for this approach to have utility in vivo, the antisense DNA must specifically target the glomerulus and, on arrival, move smoothly into the cells. Using replication-deficient recombinant adenovirus complexed to 16 um diameter polystyrene beads, the investigators have successfully placed foreign genes specifically into the glomerulus. Therefore, in the present studies we have postulated that an expressed antisense sequence recognizing the TbetaR-II and selectively delivered to the glomerulus using an adenoviral-miscrosphere shuttle system, will prevent or retard the development of glomerulosclerosis in experimental diabetes. Furthermore, these studies seek to improve glomerular gene delivery through the use of biodegradable microspheres (composed of calcium carbonate, CalCarb) and a novel, second generation adenovector (LoxAv) which, lacking all non-essential viral DNA, does not engender a host immune response, and is associated with prolonged transgene expression. The present proposal has two specific aims:
Specific aim 1 will further characterize the in vitro properties of an antisense sequence recognizing the TbetaR-II and test this construct in vivo, using an established adenoviral-microsphere shuttle system.
Specific aim 2 will pursue development of a second generation adenoviral-microsphere shuttle, utilizing LoxAv/CalCarb complexes. Once optimized, the results of both aims will be combined: the TbetaR-II antisense sequence will be placed in LoxAv, complexed to CalCarb elements of an effective gene therapy strategy including, specificity for target nucleotides, safe and accurate tissue targeting, and the provision of well tolerated, long lasting therapy.
| Bhatt, Udayan Y; Sferra, Thomas J; Johnson, Amy et al. (2002) Glomerular beta-galactosidase expression following transduction with microsphere-adenoviral complexes. Kidney Int 61:S68-72 |
| Hebert, L A; Wilmer, W A; Falkenhain, M E et al. (2001) Renoprotection: one or many therapies? Kidney Int 59:1211-26 |
| Nahman, N S; Sferra, T J; Kronenberger, J et al. (2000) Microsphere-adenoviral complexes target and transduce the glomerulus in vivo. Kidney Int 58:1500-10 |
