Antagonism of immunostimulatory CpG-oligodeoxynucleotides by 4-aminoquinolines and other weak bases: mechanistic studies

Lori  Manzel; Lucjan Strekowski; Fyaz M D Ismail; Jerry C Smith; Donald E Macfarlane

doi:10.1016/S0022-3565(24)35244-9

Back

Antagonism of immunostimulatory CpG-oligodeoxynucleotides by 4-aminoquinolines and other weak bases: mechanistic studies

Journal article

Peer reviewed

Antagonism of immunostimulatory CpG-oligodeoxynucleotides by 4-aminoquinolines and other weak bases: mechanistic studies

Lori Manzel, Lucjan Strekowski, Fyaz M D Ismail, Jerry C Smith and Donald E Macfarlane

The Journal of pharmacology and experimental therapeutics, Vol.291(3), pp.1337-1347

12/1999

DOI: 10.1016/S0022-3565(24)35244-9

PMID: 10565859

View Online

Abstract

Oligodeoxynucleotides with unmethylated CpG motifs are immunostimulatory. Chloroquine and a number of structural analogs specifically and powerfully inhibit this effect at nanomolar concentrations. We explored the mechanism of this inhibition, with 4-aminoquinolines, quinacrine, 9-aminoacridines, and novel dibasic analogs, many of which are fluorescent. WEHI 231 murine B-lymphoma cells accumulated analogs up to a concentration several hundredfold higher than the medium. Uptake was rapid, nonsaturable, reversible, and partially inhibited by monensin, an agent that collapses pH gradients within cells. Uptake did not correlate highly with efficacy as inhibitors of CpG-oligodeoxynucleotide (ODN)-induced effects, suggesting that analogs act by a specific action. Confocal microscopy revealed analogs concentrating in large peripheral organelles. CpG-ODN is taken up by cells into acidified, small, perinuclear vesicles. This uptake is thought to be necessary for immunostimulatory activity. Cellular uptake of fluorescent CpG-ODN was not inhibited by the analogs. The pH of intracellular CpG-ODN (6. 4) was not affected by analogs at the concentration required for inhibition, but pH was increased by higher concentrations. UV spectroscopy revealed no binding of analogs to CpG-ODN. Nuclear Overhauser effect spectroscopy revealed that an analog bound to phosphatidylcholine vesicles, with the ring structure of the analog buried within the lipid and the side chain facing the aqueous environment. We conclude that the analogs do not inhibit the action of CpG-ODN by preventing the uptake or acidification of CpG-ODN. It seems more likely that the analogs inhibit the efficacy of CpG-ODN by a specific action within acidified vesicles, possibly at the interface of a phospholipid membrane.

Adjuvants, Immunologic - antagonists & inhibitors

Adjuvants, Immunologic - pharmacology

Magnetic Resonance Spectroscopy

Subcellular Fractions - drug effects

Membranes, Artificial

Monensin - pharmacology

Phospholipids - chemistry

Subcellular Fractions - metabolism

Microscopy, Confocal

Lipids - chemistry

Oligonucleotides - metabolism

DNA, Single-Stranded - drug effects

Oligonucleotides - pharmacology

CpG Islands

Oligonucleotides - antagonists & inhibitors

Tumor Cells, Cultured

Alkalies - pharmacology

Aminoquinolines - pharmacology

Ionophores - pharmacology

Hydrogen-Ion Concentration

Details

Title: Subtitle: Antagonism of immunostimulatory CpG-oligodeoxynucleotides by 4-aminoquinolines and other weak bases: mechanistic studies
Creators: Lori Manzel - Department of Medicine, Veterans Affairs Medical Center and University of Iowa, Iowa City, Iowa 52242, USA
Lucjan Strekowski
Fyaz M D Ismail
Jerry C Smith
Donald E Macfarlane
Resource Type: Journal article
Publication Details: The Journal of pharmacology and experimental therapeutics, Vol.291(3), pp.1337-1347
DOI: 10.1016/S0022-3565(24)35244-9
PMID: 10565859
ISSN: 0022-3565
eISSN: 1521-0103
Language: English
Date published: 12/1999
Academic Unit: Hematology, Oncology, and Blood & Marrow Transplantation; Internal Medicine
Record Identifier: 9984094591802771

Metrics

25 Record Views

30 Times Cited - Web of Science

See more details