Hsc70 Facilitates Mannose-6-Phosphate Receptor-Mediated Intracellular Trafficking and Enhances Endosomal Release of Phosphorothioate-Modified Antisense Oligonucleotides

Author(s):  
Xue-Hai Liang ◽  
Joshua G. Nichols ◽  
Chih-Wei Hsu ◽  
Stanley T. Crooke
2020 ◽  
Vol 48 (10) ◽  
pp. 5235-5253 ◽  
Author(s):  
Stanley T Crooke ◽  
Timothy A Vickers ◽  
Xue-hai Liang

Abstract Antisense oligonucleotides (ASOs) interact with target RNAs via hybridization to modulate gene expression through different mechanisms. ASO therapeutics are chemically modified and include phosphorothioate (PS) backbone modifications and different ribose and base modifications to improve pharmacological properties. Modified PS ASOs display better binding affinity to the target RNAs and increased binding to proteins. Moreover, PS ASO protein interactions can affect many aspects of their performance, including distribution and tissue delivery, cellular uptake, intracellular trafficking, potency and toxicity. In this review, we summarize recent progress in understanding PS ASO protein interactions, highlighting the proteins with which PS ASOs interact, the influence of PS ASO protein interactions on ASO performance, and the structure activity relationships of PS ASO modification and protein interactions. A detailed understanding of these interactions can aid in the design of safer and more potent ASO drugs, as illustrated by recent findings that altering ASO chemical modifications dramatically improves therapeutic index.


1999 ◽  
Vol 7 (5) ◽  
pp. 363-371 ◽  
Author(s):  
Toshihide Takagi ◽  
Miwa Hashiguchi ◽  
Tetsuhiko Hiramatsu ◽  
Fumiyoshi Yamashita ◽  
Yoshinobu Takakura ◽  
...  

1995 ◽  
Vol 129 (1) ◽  
pp. 81-97 ◽  
Author(s):  
F Garcia-del Portillo ◽  
B B Finlay

Salmonella typhimurium is an intracellular bacterial pathogen that remains enclosed in vacuoles (SCV) upon entry into the host cell. In this study we have examined the intracellular trafficking route of S. typhimurium within epithelial cells. Indirect immunofluorescence analysis showed that bacteria initiated fusion with lysosomal membrane glycoprotein (lgp)-containing compartments approximately 15 min after bacterial internalization. This process was completed approximately 75 min later and did not require microtubules. Cation-independent (CI)- or cation-dependent (CD)-mannose 6-phosphate receptors (M6PRs) were not observed at detectable levels in SCV. Lysosomal enzymes showed a different distribution in SCV: lysosomal-acid phosphatase (LAP) was incorporated into these vacuoles with the same kinetics as lgps, while cathepsin D was present in a low proportion (approximately 30%) of SCV. Uptake experiments with fluid endocytic tracers such as fluorescein-dextran sulphate (F-DX) or horseradish-peroxidase (HRP) showed that after 2 h of uptake, F-DX was present in approximately 75% of lgp-containing vesicles in uninfected cells, while only approximately 15% of SCV contained small amounts of the tracer during the same uptake period. SCV also showed only partial fusion with HRP-preloaded secondary lysosomes, with approximately 30% of SCV having detectable amounts of HRP at 6 h after infection. These results indicate that SCV show limited accessibility to fluid endocytic tracers and mature lysosomes, and are therefore functionally separated from the endocytic route. Moreover, the unusual intracellular trafficking route of S. typhimurium inside epithelial cells has allowed us to establish the existence of two different lgp-containing vesicles in Salmonella-infected cells: one population is separated from the endocytic route, fusogenic with incoming SCV and may arise from a secretory pathway, while the second involves the classical secondary or mature lysosomes.


2019 ◽  
Vol 29 (5) ◽  
pp. 245-255 ◽  
Author(s):  
Shiyu Wang ◽  
Nickolas Allen ◽  
Thazha P. Prakash ◽  
Xue-hai Liang ◽  
Stanley T. Crooke

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