Identification of Biologically Diverse Tetrahydronaphthalen-2-ols through the Synthesis and Phenotypic Profiling of Chemically Diverse, Estradiol-Inspired Compounds.

Combining natural product fragments to design new scaffolds with unprecedented bioactivity is a powerful strategy for the discovery of tool compounds and potential therapeutics. However, the choice of fragments to couple and the biological screens to employ remain open questions in the field. By choosing a primary fragment containing the A/B ring system of estradiol and fusing it to nine different secondary fragments, we were able to identify compounds that modulated four different phenotypes: inhibition of autophagy and osteoblast differentiation, as well as potassium channel and tubulin modulation. The latter two were uncovered by using unbiased morphological profiling with a cell-painting assay. The number of hits and variety in bioactivity discovered validates the use of recombining natural product fragments coupled to phenotypic screening for the rapid identification of biologically diverse compounds.

Small molecule probes for targeting autophagy.

Autophagy is implicated in a wide range of (patho)physiological processes including maintenance of cellular homeostasis, neurodegenerative disorders, aging and cancer. As such, small molecule autophagy modulators are in great demand, both for their ability to act as tools to better understand this essential process and as potential therapeutics. Despite substantial advances in the field, major challenges remain in the development and comprehensive characterization of probes that are specific to autophagy. In this Review, we discuss recent developments in autophagy-modulating small molecules, including the specific challenges faced in the development of activators and inhibitors, and recommend guidelines for their use. Finally, we discuss the potential to hijack the process for targeted protein degradation, an area of great importance in chemical biology and drug discovery.

Structure, function and small molecule modulation of intracellular sterol transport proteins.

Intracellular sterol transport proteins (STPs) are crucial for maintaining cellular lipid homeostasis by regulating local sterol pools. Despite structural similarities in their sterol binding domains, STPs have different substrate specificities, intracellular localisation and biological functions. In this review, we highlight recent advances in the determination of STP structures and how this regulates their lipid specificities. Furthermore, we cover the important discoveries relating to the intracellular localisation of STPs, and the organelles between which lipid transport is carried out, giving rise to specific functions in health and disease. Finally, serendipitous and targeted efforts to identify small molecule modulators of STPs, as well as their ability to act as tool compounds and potential therapeutics, will be discussed.

Identification of Inhibitors of Cholesterol Transport Proteins Through the Synthesis of a Diverse, Sterol-Inspired Compound Collection.

Cholesterol transport proteins regulate a vast array of cellular processes including lipid metabolism, vesicular and non-vesicular trafficking, organelle contact sites, and autophagy. Despite their undoubted importance, the identification of selective modulators of this class of proteins has been challenging due to the structural similarities in the cholesterol-binding site. Herein we report a general strategy for the identification of selective inhibitors of cholesterol transport proteins via the synthesis of a diverse sterol-inspired compound collection. Fusion of a primary sterol fragment to an array of secondary privileged scaffolds led to the identification of potent and selective inhibitors of the cholesterol transport protein Aster-C, which displayed a surprising preference for the unnatural-sterol AB-ring stereochemistry and new inhibitors of Aster-A. We propose that this strategy can and should be applied to any therapeutically relevant sterol-binding protein.

The Synthesis of Waltherione F and Its Analogues with Modifications at the 2- and 3-Positions as Potential Antitrypanosomal Agents.

Chagas disease also know as American Trypanosomiasis (AT) is a tropical parasitic disease endemic in South America, is caused by Trypanosoma cruzi, which is transmitted by the blood-sucking insect vectors called triatomine bugs. Quinoline alkaloids from the root extract of Waltheria indica are known to possess antitrypanosomal activity. Waltherione F, one of those alkaloids, was synthesised in 5 steps in 11 % overall yield. We report here the first X-ray crystallographic confirmation of the structure of Waltherione F 3. A key step in the sequence utilised the Conrad-Limpach synthesis for the formation of the quinolin-4(1H)-one ring system. Our synthetic strategy was designed to enable the modification of the 2- and 3-positions of the scaffold, allowing the generation of a diverse library of analogues to support our on-going medicinal chemistry program that is looking for new agents to tackle this devastating disease.