Macrophages offer a paradigm switch for CNS delivery of therapeutic proteins.
OBJECTIVE
Active targeted transport of the nanoformulated redox enzyme, catalase, in macrophages attenuates oxidative stress and as such increases survival of dopaminergic neurons in animal models of Parkinson's disease. Optimization of the drug formulation is crucial for the successful delivery in living cells. We demonstrated earlier that packaging of catalase into a polyion complex micelle ('nanozyme') with a synthetic polyelectrolyte block copolymer protected the enzyme against degradation in macrophages and improved therapeutic outcomes. We now report the manufacture of nanozymes with superior structure and therapeutic indices.


METHODS
Synthesis, characterization and therapeutic efficacy of optimal cell-based nanoformulations are evaluated.


RESULTS
A formulation design for drug carriers typically works to avoid entrapment in monocytes and macrophages focusing on small-sized nanoparticles with a polyethylene glycol corona (to provide a stealth effect). By contrast, the best nanozymes for delivery in macrophages reported in this study have a relatively large size (≈ 200 nm), which resulted in improved loading capacity and release from macrophages. Furthermore, the cross-linking of nanozymes with the excess of a nonbiodegradable linker ensured their low cytotoxicity, and efficient catalase protection in cell carriers. Finally, the 'alternatively activated' macrophage phenotype (M2) utilized in these studies did not promote further inflammation in the brain, resulting in a subtle but statistically significant effect on neuronal regeneration and repair in vivo.


CONCLUSIONS
The optimized cross-linked nanozyme loaded into macrophages reduced neuroinflammatory responses and increased neuronal survival in mice. Importantly, the approach for nanoformulation design for cell-mediated delivery is different from the common requirements for injectable formulations.
Laboratory for Chemical Design of Bionanomaterials & the Department of Chemical Enzymology, Faculty of Chemistry, MV Lomonosov Moscow State University, Moscow, Russia and Department of Pharmaceutical Sciences, Center for Drug Delivery & Nanomedicine, University of Nebraska Medical Center, Omaha, NE, USA.
Natalia L
NL
Klyachko
Matthew J
MJ
Haney
Yuling
Y
Zhao
Devika S
DS
Manickam
Vivek
V
Mahajan
Poornima
P
Suresh
Shawn D
SD
Hingtgen
R Lee
RL
Mosley
Howard E
HE
Gendelman
Alexander V
AV
Kabanov
Elena V
EV
Batrakova
D000818:Animals; D001812:Blood-Brain Barrier / Q000378:metabolism*; D002374:Catalase / Q000008:administration & dosage* / Q000378:metabolism; D002417:Cattle; D002460:Cell Line; D002626:Chemistry, Pharmaceutical; D003432:Cross-Linking Reagents; D004337:Drug Carriers / Q000737:chemistry; D016503:Drug Delivery Systems; D004660:Encephalitis / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology; D004795:Enzyme Stability; D008262:Macrophage Activation; D008264:Macrophages / Q000166:cytology / Q000201:enzymology / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D053769:Nanocapsules / Q000008:administration & dosage* / Q000737:chemistry / Q000648:ultrastructure; D050997:Nanomedicine; D010316:Particle Size
D003432:Cross-Linking Reagents; D004337:Drug Carriers; D053769:Nanocapsules; D002374:Catalase
blood–brain barrier; catalase; cell-mediated drug delivery; neuroinflammation