Comparison of Five Peptide Vectors for Improved Brain Delivery of the Lysosomal Enzyme Arylsulfatase A

Abstract

Enzyme replacement therapy (ERT) is a treatment option for lysosomal storage disorders (LSDs) caused by deficiencies of soluble lysosomal enzymes. ERT depends on receptor-mediated transport of intravenously injected recombinant enzyme to lysosomes of patient cells. The blood-brain barrier (BBB) prevents efficient transfer of therapeutic polypeptides from the blood to the brain parenchyma and thus hinders effective treatment of LSDs with CNS involvement. We compared the potential of five brain-targeting peptides to promote brain delivery of the lysosomal enzyme arylsulfatase A (ASA). Fusion proteins between ASA and the protein transduction domain of the human immunodeficiency virus TAT protein (Tat), an Angiopep peptide (Ang-2), and the receptor-binding domains of human apolipoprotein B (ApoB) and ApoE (two versions, ApoE-I and ApoE-II) were generated. All ASA fusion proteins were enzymatically active and targeted to lysosomes when added to cultured cells. In contrast to wild-type ASA, which is taken up by mannose-6-phosphate receptors, all chimeric proteins were additionally endocytosed via mannose-6-phosphate-independent routes. For ASA-Ang-2, ASA-ApoE-I, and ASA-ApoE-II, uptake was partially due to the low-density lipoprotein receptor-related protein 1. Transendothelial transfer in a BBB cell culture model was elevated for ASA-ApoB, ASA-ApoE-I, and ASA-ApoE-II. Brain delivery was, however, increased only for ASA-ApoE-II. ApoE-II was also superior to wild-type ASA in reducing lysosomal storage in the CNS of ASA-knock-out mice treated by ERT. Therefore, the ApoE-derived peptide appears useful to treat metachromatic leukodystrophy and possibly other neurological disorders more efficiently.

Normalization and Improvement of CNS Deficits in Mice With Hurler Syndrome After Long-term Peripheral Delivery of BBB-targeted Iduronidase

“…Our notion of LRP-1-mediated transcytosis across the BBB via this receptor-binding peptide has also been confirmed recently when tested in a fusion protein setting with the lysosomal enzyme arylsulfatase A. 35 Secondly, unlike the mannose-6-phosphate receptor that is mostly expressed only in neurons within an adult brain, LRP-1 and very low-density lipoprotein receptor are abundantly expressed on neurons, astrocytes, and pericytes. 21,22 This adopted delivery pathway of IDUAe via LPR1 would facilitate secondary distribution of IDUAe after its arrival into the CNS, thus leads to rapid "on-target" delivery of IDUAe (not IDUAc) to affected cells, such as perivascular cells with abnormal lysosomal storage, activated astrocytes and neurons (especially Purkinje neurons), resulting in significant neurological efficacy.…”

A peptide-linked recombinant glucocerebrosidase for targeted neuronal delivery: Design, production, and assessment

“…Besides the creation of GCase-Tat, a receptor-dependent delivery strategy was employed for facilitating the passage of GCase across the BBB. Peptides from apolipoproteins B and E, capable of mediating lysosomal enzyme delivery across the BBB, have been tested and compared to Tat (Böckenhoff et al, 2014; Spencer and Verma, 2007). Specifically, ApoB has been used to deliver GCase across the BBB.…”

RNA interference for glioblastoma therapy: Innovation ladder from the bench to clinical trials

“…Here, either small or large molecules can bind to specific receptors on the surface of endothelial cells and cross the BBB by transcytosis mechanisms [22]. Several CNS targeting ligands such as apolipoprotein E [21,140,141], Angiopep-2 [142,143], transferrin [144,145], and Rabies virus glycoprotein (RVG) peptide [20,146,147] have shown to improve drug delivery to the brain through the BBB. For example, mouse tail vein injection of siRNA molecules attached to RVG peptides (siRNA-RVG) showed a significant increase of RNA delivery to the brain parenchyma [20].…”