R. Pala, S.M. Nauli
University of California Irvine,
Keywords: nanomedicine, ciliopathy, hypertension, primary cilia, chemosensory, imaging
Summary:Ciliopathies caused by abnormal function of primary cilia include expanding spectrum of kidney, liver, and heart disorders. There is currently no treatment available for patients with cilia dysfunction. Nanoscience promises to provide huge clinical impacts on advanced disease management and personalized medicine. Nanoparticles have been used for targeted drug delivery at a desired site and a sustained drug release. Therefore, we generated and compared two different metal and polymer cilia-targeted nanoparticle drug delivery systems (DDS), i.e. gold (Au) and poly lactic-co-glycolic acid (PLGA) nanoparticles (NPs) for the first time. These drug delivery systems were targeted to dopamine-receptor type-5 (DR-5) on primary cilia and also loaded with fenoldopam (FD). The structures and sizes of DDS were visualized with transmission electron microscopy. The size of the DDS was also confirmed with the dynamic light scattering. The diameters of Au and PLGA-NPs were approximately 40 ± 2.5 and 102 ± 4.8 nm, respectively. The surface charge of Au NPs (−47.3 ± 1.2 mV) was significantly more negative than PLGA-NPs (−25.9 ± 1.0 mV). Fourier transform infrared spectroscopy also confirmed the conjugation of DR-5 antibody with both DDS. A standard high-performance liquid chromatography curve for FD was prepared to standardize FD quantitation. FD was significantly more efficient to be loaded and released into/from PLGA-NPs. Live-imaging of single-cell-single-cilium analysis confirmed that DDS specifically targeted to primary cilia. Importantly, both DDS showed maximum binding to cilia in less than 2 hours. To compare the efficacies among DDS and fenoldopam-alone, we used endothelia-specific Pkd2 knockout mouse model. While Au-NPs significantly reduced blood pressure in hypertensive Pkd2 mice, PLGA-NPs further decreased blood pressure toward the wild-type’s level. Short 30 min infusions of FD showed no long-term effect, indicating an advantage of sustained-release of DDS. Because long-term hypertension can influence heart function, comprehensive heart parameters were analyzed using a working heart system. While fenoldopam-alone seemed to have no effect on Pkd2 mice, fenoldopam had an immediate effect during infusion. A short infusion of fenoldopam significantly decreased blood pressure followed by reflex tachycardia. While DDS did not show any advantages over fenoldopam-alone in cultured cells in vitro, DDS delivered FD more superior than FD-alone by eliminating the side effect of reflex tachycardia in mouse models. Although slow infusion was required for fenoldopam-alone in mice, bolus injection was possible for DDS. Though there were no significant therapeutic differences between Au-NPs and PLGA-NPs, PLGA-NPs tended to correct ciliopathy parameters closer to normal physiological levels, indicating PLGA-NPs were better cargos than Au-NPs. Our toxicity studies reveal that both DDS showed no systemic adverse effect. In summary, our studies provided scientific evidence that existing pharmacological agent could be personalized with advanced nanomaterials to treat ciliopathy by targeting cilia without the need of generating new drugs. Our studies opened a paradigm of harnessing a novel mechanism for future strategies in nanomedicine toward a more personalized medicine for ciliopathy.