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306

M. Campbell et al.

Fig. 34.2 Retinal flatmount analysis of claudin-5 expression in the retinas of mice receiving a nontargeting (NT) siRNA showed distinct peripheral staining of claudin-5 in the retinal vasculature. This peripheral staining appeared diffuse and discontinuous in the retinas of mice 24 and 48 h post-injection of siRNA targeting claudin-5, with levels returning to normal 72 h post-injection of siRNA

was shown to be a transient event as 72 h post injection of siRNA, there was no extra-vascular staining of the nuclear layers of the retina (Fig. 34.3).

34.3.3 MRI Analysis of Ibrb Integrity Following Rnai of Claudin-5

Forty-eight hours post injection of siRNA targeting claudin-5, mice were injected with the MRI tracer molecule Gd-DTPA (742 Da). As evidenced by Gd-DTPA deposition within the eye, the iBRB was shown to be compromised in that dark contrasting was observed both in the retina and in the vitreous region of the mouse eye (Fig. 34.4).

34.4 Discussion

The retinal microvasculature plays an essential role in supplying the high-energy demanding retina with oxygen-enriched blood. The endothelial cells that line these fine capillaries have evolved ‘tight junctions’, which form a selective and regulatable barrier. However, oxygen can still diffuse from these cells, and other essential materials can be delivered to the retina by special transporters located in the membranes

34 Reversible and Size-Selective Opening of the Inner Blood-Retina Barrier

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Fig. 34.3 Extravasation of Hoechst 33342 was evident in 12 μm retinal cryosections, with the Inner Nuclear Layer (INL) appearing stained at 24 h and distinct Outer Nuclear Layer (ONL) staining at 48 h post delivery of CLDN5 siRNA. In all control groups, Hoechst staining was manifested solely in the nuclei of retinal blood vessels which diffuse within the retina as far as the Outer Plexiform Layer (OPL). Scale bar approx. 20 μm. (IPL) Inner Plexiform Layer; (GCL) Ganglion Cell Layer

Fig. 34.4 48 h post injection of siRNA targeting claudin-5, Gd-DTPA permeation was evident within the eyes of mice. The image to the left represents a T1-weighted MRI image of a mouse 48 h post-injection of claudin-5 siRNA pre-Gd-DTPA injection. The image to the right shows the same mouse post-Gd-DTPA injection, showing enhanced contrasting due to Gd-DTPA extravasation within the eye

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of the endothelial cells. Complete breakdown of the iBRB would have disastrous consequences for overall retina function. However, if transient, reversible opening of the barrier could be achieved, an avenue would be available for experimental delivery to the retina, in animals such as mice, of agents which may modulate neuronal function.

We have herein described a method whereby the iBRB can be induced to become transiently and size-selectively permeable to molecules below approximately 1 kDa. Although this is an experimental approach using a hydrodynamic technique of inoculation, a viral mediated delivery system could in principle ‘humanize’ this approach to allow for the delivery of a wide range of therapeutics to the inner retina.

The potential to exploit transient compromises in iBRB integrity also has far reaching implications for the development of experimental animal models of neurodegenerative diseases of the retina, for therapeutic applications involving drug delivery/drug screening in mice and for advancing our understanding of iBRB function in general.

Acknowledgments This work was supported by the Wellcome Trust, Fighting Blindness Ireland, and Science Foundation Ireland.

References

Anderson JM (2001) Molecular structure of tight junctions and their role in epithelial transport. News Physiol Sci 16:126–130

Antonetti DA, Barber AJ, Hollinger LA et al (1999) Vascular endothelial growth factor induces rapid phosphorylation of tight junction proteins occludin and zonula occluden 1. A potential mechanism for vascular permeability in diabetic retinopathy and tumors. J Biol Chem Aug 13 274(33):23463–23467

Campbell M, Kiang AS, Kenna PF et al (2008) RNAi-mediated reversible opening of the bloodbrain barrier. J Gene Med 10(8):930–947

Fanning AS, Anderson JM (1998) PDZ domains and the formation of protein networks at the plasma membrane. Curr Top Microbiol Immunol 228:209–233

Kiang AS, Palfi A, Ader M et al (2005) Toward a gene therapy for dominant disease: validation of an RNA interference-based mutation-independent approach. Mol Ther 12(3):555–561

Koto T, Takubo K, Ishida S et al (2007) Hypoxia disrupts the barrier function of neural blood vessels through changes in the expression of claudin-5 in endothelial cells. Am J Pathol 170(4):1389–1397

Nitta T, Hata M, Gotoh S et al (2003) Size-selective loosening of the blood-brain barrier in claudin- 5-deficient mice. J Cell Biol 161(3):653–660

Riesen FK, Rothen-Rutishauser B, Wunderli-Allenspach H (2002) A ZO1-GFP fusion protein to study the dynamics of tight junctions in living cells. Histochem Cell Biol 117(4):307-315 AprEpub 2002 Mar 29

Sakakibara A, Furuse M, Saitou M et al (1997) Possible involvement of phosphorylation of occludin in tight junction formation. J Cell Biol Jun 16 137(6):1393–1401