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Journal of Drug Delivery
Volume 2017, Article ID 4070793, 12 pages
https://doi.org/10.1155/2017/4070793
Research Article

In Vivo siRNA Delivery and Rebound of Renal LRP2 in Mice

Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA

Correspondence should be addressed to Michael T. Eadon; ude.iupui@nodaem

Received 11 August 2017; Revised 26 October 2017; Accepted 20 November 2017; Published 20 December 2017

Academic Editor: Ambikanandan Misra

Copyright © 2017 Michael T. Eadon et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

siRNA stabilized for in vivo applications is filtered and reabsorbed in the renal proximal tubule (PT), reducing mRNA expression transiently. Prior siRNA efforts have successfully prevented upregulation of mRNA in response to injury. We proposed reducing constitutive gene and protein expression of LRP2 (megalin) in order to understand its molecular regulation in mice. Using siRNA targeting mouse LRP2 (siLRP2), reduction of LRP2 mRNA expression was compared to scrambled siRNA (siSCR) in mouse PT cells. Mice received siLRP2 administration optimized for dose, administration site, carrier solution, administration frequency, and administration duration. Kidney cortex was collected upon sacrifice. Renal gene and protein expression were compared by qRT-PCR, immunoblot, and immunohistochemistry (IHC). Compared to siSCR, siLRP2 reduced mRNA expression in PT cells to . In mouse kidney cortex, siLRP2 reduced mRNA expression to 74.8 ± 6.3% 3 h and 70.1 ± 6.3% 6 h after administration. mRNA expression rebounded at 12 h (160.6 ± 11.2%). No megalin renal protein expression reduction was observed by immunoblot or IHC, even after serial twice daily dosing for 3.5 days. Megalin is a constitutively expressed protein. Although LRP2 renal mRNA expression reduction was achieved, siRNA remains a costly and inefficient intervention to reduce in vivo megalin protein expression.