PEGylated HSA Nanoparticles Enhance BDNF/NT3 Stability, Ocular Delivery, and Protect Cells from Oxidative Stress
Background
Neurotrophins like brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT3) are crucial for neuronal survival and homeostasis, offering therapeutic potential for neurodegenerative diseases and retinal disorders. However, their clinical application is severely hampered by inherent protein instability and rapid clearance from target tissues. This necessitates advanced delivery systems that can protect these delicate proteins, ensure sustained release, and facilitate their intracellular uptake to exert their beneficial effects, especially in sensitive areas like the eye.
Study Design
Researchers developed PEGylated human serum albumin (HSA) nanoparticles encapsulating BDNF and NT3, with nominal neurotrophin concentrations of 5 µg/mL (NeO5) or 10 µg/mL (NeO10). Nanoparticle characteristics were assessed via multiangle dynamic light scattering, electrophoretic light scattering, and atomic force microscopy. In vivo, the nanoparticles were delivered via intravitreal injection in rabbits, with ocular biodistribution of BDNF quantified by ELISA. Functional delivery and protection against oxidative stress were evaluated in sodium iodate-stressed ARPE-19 and 6-hydroxydopamine-stressed SH-SY5Y human cell lines using ELISA, JC-1 analysis, Annexin V/PI flow cytometry, HPLC for malondialdehyde, and RT-qPCR for gene expression.
Results
Both NeO5 and NeO10 formulations formed stable, spherical nanoparticles ranging from 5.9-54.2 nm with a low polydispersity index of approximately 0.18, maintaining colloidal integrity for over 28 days. In vivo, BDNF was detectable in rabbit ocular tissues for up to 72 h post-intravitreal injection, and RT-qPCR profiling did not indicate a coordinated pro-apoptotic response under the tested conditions. In vitro, the nanoparticle treatment significantly enhanced intracellular BDNF and NT3 levels. The NeO10 formulation, in particular, demonstrated superior efficacy. > Nanoparticle treatment significantly increased intracellular BDNF and NT3 levels, improved viability, reduced apoptotic cell fractions, and markedly decreased lipid peroxidation, particularly for NeO10.These findings suggest robust cellular uptake and functional neuroprotection against oxidative stress-associated cellular damage.
Key Findings
- PEGylated HSA nanoparticles (NeO5, NeO10) formed stable, spherical particles (5.9-54.2 nm) with low polydispersity (≈ 0.18).
- Nanoparticles maintained colloidal integrity and stability for over 28 days.
- BDNF was detectable in rabbit ocular tissues for up to 72 h after intravitreal injection.
- Nanoparticle treatment significantly increased intracellular BDNF and NT3 levels in human cells.
- NeO10 formulation markedly improved cell viability, reduced apoptosis, and decreased lipid peroxidation in stressed human cells.
Why It Matters
This study presents a promising strategy for overcoming the significant challenges of neurotrophin delivery, particularly for ocular and neurodegenerative conditions. The development of stable, PEGylated HSA nanoparticles capable of sustained BDNF/NT3 release and intracellular delivery could revolutionize treatment paradigms. This approach could enable more effective and prolonged neurotrophin therapy, reducing dosing frequency and improving therapeutic outcomes by protecting the active proteins from degradation and rapid clearance. It paves the way for future clinical translation of neurotrophins, potentially impacting conditions like retinal degeneration or Parkinson's disease where oxidative stress and neurotrophin deficiency play key roles.
bdnf
nt3
neurotrophin
nanoparticles
drug-delivery
ocular