G-protein-coupled bile acid receptor 1 (GPBAR1, TGR5) agonists reduce the production of proinflammatory cytokines and stabilize the alternative macrophage phenotype.

GPBAR1 (also known as TGR5) is a G-protein-coupled receptor (GPCR) that triggers intracellular signals upon ligation by various bile acids. The receptor has been studied mainly for its function in energy expenditure and glucose homeostasis, and there is little information on the role of GPBAR1 in the context of inflammation. After a high-throughput screening campaign, we identified isonicotinamides exemplified by compound 3 as nonsteroidal GPBAR1 agonists. We optimized this series to potent derivatives that are active on both human and murine GPBAR1. These agonists inhibited the secretion of the proinflammatory cytokines TNF-α and IL-12 but not the antiinflammatory IL-10 in primary human monocytes. These effects translate in vivo, as compound 15 inhibits LPS induced TNF-α and IL-12 release in mice. The response was GPBAR1 dependent, as demonstrated using knockout mice. Furthermore, agonism of GPBAR1 stabilized the phenotype of the alternative, noninflammatory, M2-like type cells during differentiation of monocytes into macrophages. Overall, our results illustrate an important regulatory role for GPBAR1 agonists as controllers of inflammation.

S1P receptor mediated activity of FTY720 phosphate mimics.

Various carboxylic acids, phosphonic acids, sulfonic acids, tetrazoles as well as sulfonylhydantoins were prepared as phosphate mimics of the chiral aminophosphate 1-P to act as agonists on the S1P(1) receptor. It was found that amino phosphonates and amino carboxylates are potent S1P(1) binders. beta-Amino acid 11 could be shown to reversibly reduce blood lymphocyte counts in rats after po administration.

Total synthesis of five thapsigargins: guaianolide natural products exhibiting sub-nanomolar SERCA inhibition.

Herein we describe the total synthesis of five guaianolide natural products: thapsigargin, thapsivillosin C, thapsivillosin F, trilobolide and nortrilobolide. Prodrug derivatives of thapsigargin have shown selective in vivo cytotoxicity against prostate tumours and the need for further investigation of this phenomenon highlights the importance of these total syntheses. The first absolute stereochemical assignment of thapsivillosin C is also delineated.

Synthesis of borondipyrromethene (BODIPY)-labeled sphingosine derivatives by cross-metathesis reaction.

A new efficient and flexible synthesis of fluorescently labeled sphingosine derivatives from commercially available Garner aldehyde (8) is described. For this, appropriate alkenylated borondipyrromethene (BODIPY) dyes were synthesized and used for the first time in a cross-metathesis reaction, the key step of the approach. The labeled sphingosines with appropriate chain length were accepted as substrates by sphingosine kinases (SPHKs), yielding the corresponding phosphorylated products. One of these derivatives (11d) was identified as the first reported selective substrate for SPHK-1.

One-step labelling of sphingolipids via a scrambling cross-metathesis reaction.

The alkyl chain in the backbone of sphingosine derivatives can be exchanged with functionalised (labelled) side chains in a single step under cross-metathesis reaction conditions.

Synthesis of the thapsigargins.

The thapsigargins are a family of complex guaianolides with potent and selective Ca(2+)-modulating properties. This article documents the evolution of a synthetic route through several iterations to a final practical and scaleable synthetic route capable of generating both unnatural and natural products based around the guaianolide skeleton.