ABSTRACT
[This corrects the article DOI: 10.3389/fimmu.2020.607564.].
ABSTRACT
The synthesis of a library of bacterial phosphoglycolipid, PGL-1, is described. Key features of the synthesis include regioselective esterification of the primary alcohol of the diacylglycerol moiety and an H-phosphonate method to install the phosphate in PGL-1 in comparison with earlier reported procedures. A representative set of PGL-1 analogues was prepared and evaluated for their biological activities. Results showed that the immunological activity of PGL-1 is dependent on the chain lengths of the fatty acids.
Subject(s)
Glycolipids/pharmacology , Gram-Negative Bacteria/chemistry , Immunologic Factors/pharmacology , Organophosphates/pharmacology , Animals , Dose-Response Relationship, Drug , Glycolipids/chemical synthesis , Glycolipids/chemistry , Immunologic Factors/chemical synthesis , Immunologic Factors/chemistry , Interleukin-6/antagonists & inhibitors , Interleukin-6/biosynthesis , Lipopolysaccharides/antagonists & inhibitors , Lipopolysaccharides/pharmacology , Macrophages/drug effects , Macrophages/metabolism , Mice , Molecular Structure , Organophosphates/chemical synthesis , Organophosphates/chemistry , Stereoisomerism , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Tumor Necrosis Factor-alpha/biosynthesisABSTRACT
Gouty arthritis results from the generation of uric acid crystals within the joints. These uric acid crystals activate the NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome, which is involved in chronic inflammatory diseases, including gouty arthritis. This study identified the polyenylpyrrole derivative 4-hydroxy auxarconjugatin B (4-HAB), a novel autophagy inducer, which attenuated uric acid crystals-mediated activation of the NLRP3 inflammasome in vitro and in vivo. 4-HAB dose-dependently reduced the release of interleukin (IL)-1ß, IL-18, active caspase-1 and apoptosis-associated speck-like protein (ASC) in uric acid crystals-activated macrophages. In a mechanistic study, 4-HAB was shown to inhibit uric acid crystals-induced mitochondrial damage, lysosomal rupture and ASC oligomerization. Additionally, 4-HAB inhibited the NLRP3 inflammasome through Sirt1-dependent autophagy induction. Furthermore, the anti-inflammatory properties of 4-HAB were confirmed in a mouse model of uric acid crystals-mediated peritonitis by the reduced levels of neutrophil influx, IL-1ß, active caspase-1, IL-6 and MCP-1 in lavage fluids. In conclusion, 4-HAB attenuates gouty inflammation, in part by attenuating activation of the NLRP3 inflammasome through the Sirt1/autophagy induction pathway.
Subject(s)
Arthritis, Gouty/pathology , Autophagy/drug effects , Inflammasomes/metabolism , Inflammation/pathology , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Pyrroles/pharmacology , Animals , Arthritis, Gouty/complications , CARD Signaling Adaptor Proteins/metabolism , Cell Line , Disease Models, Animal , Humans , Inflammation/complications , Lipopolysaccharides , Lysosomes/drug effects , Lysosomes/metabolism , Macrophages/drug effects , Macrophages/metabolism , Male , Mice, Inbred C57BL , Mitochondria/drug effects , Mitochondria/pathology , Models, Biological , Organelle Biogenesis , Protein Multimerization/drug effects , Pyrroles/chemistry , Sirtuin 1/metabolismABSTRACT
Conjugated polyenes are a class of widely occurring natural products with various biological functions. We previously identified 4-hydroxy auxarconjugatin B (4-HAB) as anti-inflammatory agent with an IC50 of ~20 µM. In this study, we synthesized a new anti-inflammatory 4-HAB analogue, F240B, which has an IC50 of less than 1 µM. F240B dose-dependently induced autophagy by increasing autophagic flux, LC3 speck formation and acidic vesicular organelle formation. F240B inhibited NACHT, LRR and PYD domain-containing protein 3 (NLRP3) inflammasome activation through autophagy induction. In a mechanistic study, F240B inhibited interleukin (IL)-1ß (IL-1ß) precursor expression, promoted degradation of NLRP3 and IL-1ß, and reduced mitochondrial membrane integrity loss in an autophagy-dependent manner. Additionally, F240B inhibited apoptosis-associated speck-like protein containing a CARD (ASC) oligomerization and speck formation without affecting the interaction between NLRP3 and ASC or NIMA-related kinase 7 (NEK7) and double-stranded RNA-dependent kinase (PKR). Furthermore, F240B exerted in vivo anti-inflammatory activity by reducing the intraperitoneal influx of neutrophils and the levels of IL-1ß, active caspase-1, IL-6 and monocyte chemoattractant protein-1 (MCP-1) in lavage fluids in a mouse model of uric acid crystal-induced peritonitis. In conclusion, F240B attenuated the NLRP3 inflammasome through autophagy induction and can be developed as an anti-inflammatory agent in the future.
Subject(s)
Anti-Inflammatory Agents/pharmacology , Autophagy/drug effects , Inflammasomes/metabolism , Macrophages/drug effects , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Peritonitis/prevention & control , Animals , Anti-Inflammatory Agents/chemical synthesis , Autophagy-Related Proteins/metabolism , Cytokines/metabolism , Disease Models, Animal , Humans , Inflammation Mediators/metabolism , Macrophages/metabolism , Macrophages/pathology , Male , Mice , Mice, Inbred C57BL , Mitochondria/drug effects , Mitochondria/metabolism , Mitochondria/pathology , Peritonitis/chemically induced , Peritonitis/metabolism , Peritonitis/pathology , Protein Stability , RAW 264.7 Cells , Signal Transduction , THP-1 Cells , Uric AcidABSTRACT
Glycosaminoglycans (GAGs) regulate many important physiological processes. A pertinent issue to address is whether GAGs encode important functional information via introduction of position specific sulfate groups in the GAG structure. However, procurement of pure, homogenous GAG motifs to probe the "sulfation code" is a challenging task due to isolation difficulty and structural complexity. To this end, we devised a versatile synthetic strategy to obtain all the 16 theoretically possible sulfation patterns in the chondroitin sulfate (CS) repeating unit; these include rare but potentially important sulfated motifs which have not been isolated earlier. Biological evaluation indicated that CS sulfation patterns had differing effects for different breast cancer cell types, and the greatest inhibitory effect was observed for the most aggressive, triple negative breast cancer cell line MDA-MB-231.
