In vivo targeting and multimodal imaging of cerebral amyloid-β aggregates using hybrid GdF3 nanoparticles
Abstract
Aim: To propose a new multimodal imaging agent targeting amyloid-β (Aβ) plaques in Alzheimer’s disease. Materials & methods: A new generation of hybrid contrast agents, based on gadolinium fluoride nanoparticles grafted with a pentameric luminescent-conjugated polythiophene, was designed, extensively characterized and evaluated in animal models of Alzheimer’s disease through MRI, two-photon microscopy and synchrotron x-ray phase-contrast imaging. Results & conclusion: Two different grafting densities of luminescent-conjugated polythiophene were achieved while preserving colloidal stability and fluorescent properties, and without affecting biodistribution. In vivo brain uptake was dependent on the blood–brain barrier status. Nevertheless, multimodal imaging showed successful Aβ targeting in both transgenic mice and Aβ fibril-injected rats.
Plain language summary
The design and study of a new contrast agent targeting amyloid-β (Aβ) plaques in Alzheimer’s disease (AD) is proposed. Aβ plaques are the earliest pathological sign of AD, silently appearing in the brain decades before the symptoms of the disease are manifested. While current detection of Aβ plaques is based on nuclear medicine (a technique using a radioactive agent), a different kind of contrast agent is here evaluated in animal models of AD. The contrast agent consists of a nanoparticle made of gadolinium and fluorine ions (core), and decorated with a molecule previously shown to bind to Aβ plaques (grafting). The core is detectable with MRI and x-ray imaging, while the grafting molecule is detectable with fluorescence imaging, thus allowing different imaging methods to be combined to study the pathology. In this work, the structure, stability and properties of the contrast agent have been verified in vitro (in tubes and on brain sections). Then the ability of the contrast agent to bind to Aβ plaques and provide a detectable signal in MRI, x-ray or fluorescence imaging has been demonstrated in vivo (in rodent models of AD). This interdisciplinary research establishes the proof of concept that this new class of versatile agent contrast can be used to target pathological processes in the brain.
Tweetable abstract
New multimodal contrast agent developed at University of Lyon: a functionalized gadolinium-based nanoparticle shows successful targeting of amyloid-β fibrils and in vivo detection with two-photon microscopy and MRI in animal models of Alzheimer’s disease.
Graphical abstract
Papers of special note have been highlighted as: • of interest; •• of considerable interest
References
- 1. . Development of positron emission tomography β-amyloid plaque imaging agents. Semin. Nucl. Med. 42(6), 423–432 (2012).
- 2. . Nanoparticles as contrast agents for brain nuclear magnetic resonance imaging in Alzheimer’s disease diagnosis. J. Mater. Chem. B 5(35), 7216–7237 (2017).
- 3. Magnetic nanoparticles applications for amyloidosis study and detection: a review. Nanomaterials 8(9), 740 (2018).
- 4. Detection of amyloid plaques targeted by bifunctional USPIO in Alzheimer’s disease transgenic mice using magnetic resonance microimaging. PLOS ONE 8(2), e57097 (2013).
- 5. . Nanotheranostics: Congo red/rutin-MNPs with enhanced magnetic resonance imaging and H2O2-responsive therapy of Alzheimer’s disease in APPswe/PS1dE9 transgenic mice. Adv. Mater. 27(37), 5499–5505 (2015).
- 6. Curcumin-conjugated magnetic nanoparticles for detecting amyloid plaques in Alzheimer’s disease mice using magnetic resonance imaging (MRI). Biomaterials 44, 155–172 (2015).
- 7. Validation by magnetic resonance imaging of the diagnostic potential of a heptapeptide-functionalized imaging probe targeted to amyloid-β and able to cross the blood–brain barrier. J. Alzheimers Dis. 60(4), 1547–1565 (2017).
- 8. Amyloid polymorphisms constitute distinct clouds of conformational variants in different etiological subtypes of Alzheimer’s disease. Proc. Natl Acad. Sci. USA 114(49), 13018–13023 (2017).
- 9. Two-photon fluorescence and magnetic resonance specific imaging of Aβ amyloid using hybrid nano-GdF3 contrast media. ACS Appl. Biol. Mater. 1(2), 462–472 (2018). • Seminal study describing the GdF3 nanoprobe.
- 10. Luminescent conjugated oligothiophenes for sensitive fluorescent assignment of protein inclusion bodies. Chembiochem 14(5), 607–616 (2013). • Comparison of luminescent-conjugated polythiophenes for targeting of brain amyloids.
- 11. Rare earth fluoride nanoparticles obtained using charge transfer complexes: a versatile and efficient route toward colloidal suspensions and monolithic transparent xerogels. Langmuir 27(9), 5555–5561 (2011).
- 12. Mediating gel formation from structurally controlled poly(electrolytes) through multiple ‘head-to-body’ electrostatic interactions. Macromol. Rapid Commun. 36(1), 55–59 (2015).
- 13. . Measurement of photoluminescence quantum yields. Rev. J. Phys. Chem. 75(8), 991–1024 (1971).
- 14. Differential effects of amyloid-β 1-40 and 1-42 fibrils on 5-HT1A serotonin receptors in rat brain. Neurobiol. Aging 40, 11–21 (2016).
- 15. Aβ42-driven cerebral amyloidosis in transgenic mice reveals early and robust pathology. EMBO Rep. 7(9), 940–946 (2006).
- 16. Synchrotron radiation x-ray phase micro-computed tomography as a new method to detect iron oxide nanoparticles in the brain. Mol. Imaging Biol. 15(5), 552–559 (2013).
- 17. Hybrid multimodal contrast agent for multiscale in vivo investigation of neuroinflammation. Nanoscale 13(6), 3767–3781 (2021).
- 18. . Simultaneous phase and amplitude extraction from a single defocused image of a homogeneous object. J. Microsc. 206(1), 33–40 (2002).
- 19. . The PyHST2 hybrid distributed code for high speed tomographic reconstruction with iterative reconstruction and a priori knowledge capabilities. Nucl. Instrum. Methods Phys. Res. Sect. B 324, 41–48 (2014).
- 20. Computer vision tools to optimize reconstruction parameters in x-ray in-line phase tomography. Phys. Med. Biol. 59(24), 7767–7775 (2014).
- 21. Long-term in vivo imaging of β-amyloid plaque appearance and growth in a mouse model of cerebral β-amyloidosis. J. Neurosci. 31(2), 624–629 (2011).
- 22. Repeatable target localization for long-term in vivo imaging of mice with 2-photon microscopy. J. Neurosci. Methods 205(2), 357–363 (2012).
- 23. Novel pentameric thiophene derivatives for in vitro and in vivo optical imaging of a plethora of protein aggregates in cerebral amyloidoses. ACS Chem. Biol. 4(8), 673–684 (2009).
- 24. In vivo MRI assessment of permanent middle cerebral artery occlusion by electrocoagulation: pitfalls of procedure. Exp. Transl. Stroke Med. 2(1), 4 (2010).
- 25. Characterization of impaired cerebrovascular structure in APP/PS1 mouse brains. Neuroscience 385, 246–254 (2018).
- 26. Gd-nanoparticles functionalization with specific peptides for ß-amyloid plaques targeting. J. Nanobiotechnol. 14(1), 60 (2016).
- 27. Multimodal imaging Gd-nanoparticles functionalized with Pittsburgh compound B or a nanobody for amyloid plaques targeting. Nanomedicine 12(14), 1675–1687 (2017).
- 28. Antibody-conjugated, dual-modal, near-infrared fluorescent iron oxide nanoparticles for antiamyloidgenic activity and specific detection of amyloid-β fibrils. Int. J. Nanomed. 8(1), 4063–4076 (2013).
- 29. . Standardization of research methods employed in assessing the interaction between metallic-based nanoparticles and the blood–brain barrier: present and future perspectives. J. Control. Rel. 296, 202–224 (2019). •• A systematic review of the methods by which metallic-based nanoparticles are characterized and assessed in vivo.
- 30. Nanoparticles as contrast agents for the diagnosis of Alzheimer’s disease: a systematic review. Nanomedicine 15(7), 725–743 (2020). •• Includes 33 studies of various nanoparticles for Alzheimer’s disease imaging, with comparison of coating, functionalization, MRI relaxivity, toxicity and bioavailability.
- 31. . Quantum dots as a theranostic approach in Alzheimer’s disease: a systematic review. Nanomedicine 16(18), 1595–1611 (2021).
- 32. Potential of fluorescent nanoprobe in diagnosis and treatment of Alzheimer’s disease. Nanomedicine 17(17), 1191–1211 (2022).
- 33. Camelid single-domain antibodies: a versatile tool for in vivo imaging of extracellular and intracellular brain targets. J. Control. Rel. 243, 1–10 (2016).
- 34. Chemically-defined camelid antibody bioconjugate for the magnetic resonance imaging of Alzheimer’s disease. mAbs 9(6), 1016–1027 (2017).
- 35. . Nanoparticles enhance brain delivery of blood–brain barrier-impermeable probes for in vivo optical and magnetic resonance imaging. Proc. Natl Acad. Sci. USA 108(46), 18837–18842 (2011).
- 36. Towards non-invasive diagnostic imaging of early-stage Alzheimer’s disease. Nat. Nanotechnol. 10(1), 91–98 (2015).
- 37. Galantamine nanoparticles outperform oral galantamine in an Alzheimer’s rat model: pharmacokinetics and pharmacodynamics. Nanomedicine 16(15), 1281–1296 (2021).
- 38. Increased separability of K-edge nanoparticles by photon-counting detectors for spectral micro-CT. J. X-ray Sci. Technol. 26(5), 707–726 (2018).
- 39. Hybrid nano-GdF3 contrast media allows pre-clinical in vivo element-specific K-edge imaging and quantification. Sci. Rep. 9(1), 12090 (2019).
- 40. Multimodal imaging with NanoGd reveals spatiotemporal features of neuroinflammation after experimental stroke. Adv. Sci. (Weinh.) 8(17), e2101433 (2021). •• First report to decipher the working mechanism of magnetic resonance signals induced by a nanoparticle passively targeted at phagocytic cells by performing intravital microscopy back-to-back with MRI.
