Analysis of cathepsin B and cathepsin L treatment to clear toxic lysosomal protein aggregates in neuronal ceroid lipofuscinosis.

Abstract

Proteolysis mediated by lysosomal cathepsin proteases maintains a physiological flow in autophagy, phagocytosis and endocytosis. Neuronal Ceroid Lipofuscinosis (NCL) is a childhood neurodegenerative disorder characterized by disturbed autophagic flow and pathological accumulation of proteins. We demonstrated a therapeutic clearance of protein aggregates after dosing NCL10 mice with recombinant human pro-cathepsin-D. Prompted by these results and speculating that cathepsins may act in a redundant and in an hierarchical manner we envisaged that a treatment with human recombinant cysteine proteases pro-cathepsin-L (proCTSL) and pro-cathepsin-B (proCTSB) could similarly be used to induce protein degradation. Both enzymes were taken up by mannose 6-phosphate receptor- and LRP-receptor-mediated endocytosis and processed to the lysosomal mature cathepsins. In murine NCL10 astrocytes an abnormal increase in LAMP1 and saposin expression was revealed. Although proCTSB application did not improve this phenotype, proCTSL treatment led to reduced saposin-C levels in this model as well as in an acute brain slice model. Intracerebral dosing in a NCL10 mouse model revealed cellular and lysosomal uptake of both enzymes. Only proCTSL mildly reduced saposin-C levels and attenuated reactive astrogliosis. Application of both proteases did not improve weight loss and mortality of mutant mice. Our data reveal that although recombinant lysosomal proteases can be efficiently delivered to neuronal lysosomes cysteine proteases are less efficient in protein aggregates clearance as compared to the cathepsin-D treatment. Our data including in vitro degradation assays support the idea that bulk proteolysis requires a hierarchical process in which both aspartyl and cysteine hydrolases play a role.

• Authors: Alessandro Di Spiezio, André R A Marques, Lina Schmidt, Niklas Thießen, Lisa Gallwitz, Jens Fogh, Udo Bartsch, Paul Saftig
• Journal: Biochimica et biophysica acta. Molecular basis of disease (Biochim Biophys Acta Mol Basis Dis) Vol. 1867 Issue 10 Pg. 166205 (10 01 2021) ISSN: 1879-260X [Electronic] Netherlands
• PMID: 34214607 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2021 Elsevier B.V. All rights reserved.

Chemical References

• Protein Aggregates
• Proteins
• lysosomal proteins
• Cathepsin B
• Cathepsin L

Topics

• Animals
• Autophagy (physiology)
• Brain (metabolism)
• Cathepsin B (metabolism)
• Cathepsin L (metabolism)
• Disease Models, Animal
• Female
• Gliosis (metabolism)
• Lysosomes (metabolism)
• Male
• Mice
• Mice, Knockout
• Neuronal Ceroid-Lipofuscinoses (metabolism)
• Neurons (metabolism)
• Protein Aggregates (physiology)
• Proteins (metabolism)
• Proteolysis