Therapeutic alteration of transplantable tissues through in situ or ex vivo exposure to RNA interference molecules
The present invention, at least in part, relates to the discovery of efficacious delivery of an RNAi agent (in preferred aspects of the invention, an siRNA) to a transplantable tissue. Organ rejection, transplantation-mediated transmission of viral infection, and triggering of apoptosis in transplanted tissues can each be minimized by the methods and compositions of the instant invention. The RNAi agent(s) of the instant invention can be delivered as “naked” molecules, or using liposomal and other modes of delivery, to transplantable tissues. Such delivery can occur via perfusion of the RNAi agent in solution through the vasculature of a whole or partial organ; or tissues including transplantable cells and cell lines may be bathed, injected or otherwise treated with RNAi agents. Preferred transplantable tissues include, for example, pancreas, liver, kidney, heart, lung, and all cells and cell lines derived from such tissues (e.g., pancreatic islet cells that may, e.g., be transplanted as a treated population).
1. A method of inhibiting apoptosis-induced ischemic injury of a transplanted allograft organ, comprising perfusing the vasculature of the allograft organ with an RNAi agent capable of downmodulating ischemia-induced apoptosis, wherein the RNAi agent comprises a sense strand and an anti-sense strand, wherein the anti-sense strand is sufficiently complementary to p53 RNA to reduce the production of p53 within the allograft organ via RNA-induced silencing complex (RISC), and wherein said vascular perfusion effectively delivers the RNAi agent to cells within the allograft organ so as to counter apoptosis-induced ischemic injury of the allograft organ, wherein the method is carried out in the absence of electroporation.
2. The method of claim 1 , wherein the allograft organ is an allograft kidney or liver.
3. The method of claim 1 , wherein perfusing the vasculature of the allograft organ with an RNAi agent capable of downmodulating ischemia-induced apoptosis further comprises administering the RNAi agent in a preservation solution that comprises either saline or an immunosuppressant.
4. The method of claim 1 , wherein the RNAi agent is an siRNA molecule.
5. The method of claim 1 , wherein the RNAi agent is an shRNA molecule.
6. The method of claim 1 , wherein the RNAi agent comprises an oligonucleotide comprising a modification to a 2′-OH group, the modification being selected from the group consisting of the 2′-OH group replaced by a H, alkoxy or OR, halogen, SH, SR, amino, or CN group, wherein R is a lower alkyl, alkenyl, alkynyl, or aryl.
7. The method of claim 6 , wherein the RNAi agent comprises a 2′-O-methyl oligonucleotide.
8. The method of claim 1 , wherein the allograft organ is perfused with a solution containing said RNAi agent by retrograde or anterograde delivery.
9. The method of claim 1 , wherein the perfused RNAi agent contacts the allograft organ via lipid-mediated delivery or as a component of a liposomal delivery preparation.