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Pang Yu Hsueh, Srikanth Reddy Janga, John A Mackay, Sarah F Hamm-Alvarez; Targeting of elastin-like polypeptide nanoparticles to ICAM-1 in lacrimal glands for therapy of SjÖgren's Syndrome. Invest. Ophthalmol. Vis. Sci. 2014;55(13):4634.
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© ARVO (1962-2015); The Authors (2016-present)
Sjögren’s syndrome (SS) is an autoimmune disease that affects lacrimal gland (LG) and salivary gland, resulting in reduced secretion. Previous studies demonstrated that SS is associated with enhanced expression of proteases in endosomal/lysosomal and secretory vesicles (SVs) of LG acinar cells (LGACs) that may enhance degradation of internal and matrix proteins and promote autoimmunity. Therefore, targeted delivery of drugs into lysosomes and/or SVs of diseased LGACs may be a promising strategy to treat SS. In this study, we investigated the uptake and intracellular trafficking of nanoparticles targeted to mouse intercellular adhesion molecule (ICAM)-1, an inflammation-induced receptor that we hypothesized would be upregulated in LGACs in non-obese diabetic (NOD) mice, a SS model. Nanoparticles were comprised of diblock elastin-like polypeptides (SI ELP) fused with a mouse anti-ICAM-1 peptide (mICAM-1 SI).
Real-time RT-PCR and Western blotting were used to quantify mRNA and protein expression of ICAM-1 in LG from male 12 week NOD mice, as compared to control BALB/c mice. Confocal fluorescence microscopy was used to analyze the distribution of ICAM-1 in LG and confirm the internalization of fluorescently-labeled mICAM-1 given intravenously. Time-lapse confocal fluorescence microscopy was used to investigate the intracellular trafficking of fluorescently-labeled mICAM-1 SI in mouse ICAM-1 expressed HeLa cells.
ICAM-1 mRNA abundance in NOD mice was 13-fold higher than that in BALB/c, with mICAM-1 mostly localized to the basolateral membranes of LGACs. Fluorescently-labeled mICAM-1 SI selectively bound to either mouse ICAM-1 or endogenous human ICAM-1, triggering the endocytosis of mICAM-1 SI. Pulse-chase experiments suggested that internalized mICAM-1 SI was initially trafficked to early endosomes, which was later sorted to lysosomes. mICAM-1 SI accumulated in lysosomes after 3 hours. Intravenous injection of mICAM-1 SI likewise showed accumulation of fluorescent nanoparticles in intracellular compartments.
Our data indicated that anti-mouse ICAM-1 peptide enhances the accumulation of nanoparticles comprised of ELPs in lysosomes of LGACs, strongly suggesting targeted delivery of drugs within ELP nanoparticles to ICAM-1 as a promising and novel approach to treat the protease accumulation associated with SS.
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