Towards the Development of Chemical Biology Pipelines for Stem Cells and Receptor Characterization

Chemical biology may provide useful small molecule probes that can contribute to advancing stem cells therapeutic application and the still challenging GPCR drug research field. In this context, in this thesis we focus on the development of chemical probes to the modulation of neural stem cells (NSCs) and, in parallel, to the characterization of the recently discovered P2Y14 receptor (P2Y14R). Particularly, the first application deals with pursuing a knowledge-based phenotypic approach (i) and a functionalized congeners approach (ii). Strategies (i) and (ii) have been conducted in parallel with the deliberate aim of identifying critical targets/pathways involved in NSCs differentiation and starting points for the development of new drugs. Particularly, a focused library of chemical probes has been designed and synthesized. An experimental pipeline, evaluating hepato- and neuro-toxicity, neuroprotection and proliferation in cell lines and primary neurons has been used for prioritizing compounds with better chances to be further investigated in the NCS phenotypic assay (i). In parallel, the application of the functionalized congener approach has allowed to design fluorescent, multi-target and polyamine congeners of the selected chemical scaffold (ii). Regarding the chemical biological approach towards P2Y14R, we have recently achieved promising results that could aid in unveiling its pharmacological potential in diabetes and inflammation. In particular, we have used structural insights of the recently obtained structural information of P2Y14R to discover a new scaffold for P2Y14R antagonists. In addition, two fluorescent probes (agonist and antagonist) have been developed and their utility to detect P2Y14R using fluorescence microscopy and flow cytometry has been also successfully demonstrated. Collectively, these results provide initial clues to our understanding of stem cell biology and P2Y14R pharmacology, and could inspire powerful pharmacological tools

From Companion Diagnostics to Theranostics:A New Avenue for Alzheimer's Disease?

The recent literature signals a growing paradigm shift toward integrating therapeutics and diagnostics rather than developing and deploying them separately. In this gradual move toward more effective and personalized medications, companion diagnostics are an intermediate stage. The next step may be "theranostics", in which single chemical entities are developed to deliver therapy and diagnosis simultaneously. This strategy has been successfully exploited in oncology and is now emerging as a possibility for Alzheimer's disease, where its feasibility has caught the attention of researchers from industry and academia. Medicinal chemists do not yet completely understand the nuances of theranostic action and consequently have not yet developed universally validated strategies for developing theranostic clinical applications against Alzheimer's disease. However, given the emerging indications of the potentially enormous benefits that theranostics may bring to the fight against this devastating disease, further rigorous research is warranted

Enriching Proteolysis Targeting Chimeras with a Second Modality: When Two Are Better Than One

Proteolysis targeting chimera (PROTAC)-mediated protein degradation has prompted a radical rethink and is at a crucial stage in driving a drug discovery transition. To fully harness the potential of this technology, a growing paradigm toward enriching PROTACs with other therapeutic modalities has been proposed. Could researchers successfully combine two modalities to yield multifunctional PROTACs with an expanded profile? In this Perspective, we try to answer this question. We discuss how this possibility encompasses different approaches, leading to multitarget PROTACs, light-controllable PROTACs, PROTAC conjugates, and macrocycle-and oligonucleotide-based PROTACs. This possibility promises to further enhance PROTAC efficacy and selectivity, minimize side effects, and hit undruggable targets. While PROTACs have reached the clinical investigation stage, additional steps must be taken toward the translational development of multifunctional PROTACs. A deeper and detailed understanding of the most critical challenges is required to fully exploit these opportunities and decisively enrich the PROTAC toolbox

Discovery of sustainable drugs for neglected tropical diseases: cashew nutshell liquid (CNSL)-based hybrids target mitochondrial function and ATP production in Trypanosoma brucei.

In a search for effective and sustainable treatments for trypanosomiasis, we developed a library of hybrid compounds by merging the structural features of a previously synthesized quinone hit (4) with those of long‐chain phenolic constituents from cashew nut shell liquid (CNSL). CNSL is an agro‐waste product from cashew nut processing factories with great potential as a precursor for the production of drugs. The synthesized compounds were tested against Trypanosoma brucei brucei, including three multi‐drug resistant strains (B48, ISMR1, and aqp2/aqp3‐KO), T. congolense, and a human cell line (HFF). The most potent activity was found against T. b. brucei, the causative agent of African trypanosomiasis. Shorter‐chain derivatives were more active than the starting hit in parasite growth inhibition, displaying rapid trypanocidal activity with low micromolar EC50 values, but no discernable toxicity on human cell lines. Preliminary studies probing their mode of action on trypanosomes showed depletion of cellular ATP, followed by the depolarization of the mitochondrial membrane and ultrastructural damage to the mitochondrion. This was accompanied by the production of high levels of reactive oxygen species. We envisage that such hybrid compounds, obtained from renewable and inexpensive material, might be promising bio‐based, sustainable hits for anti‐trypanosomatid drug discovery

Design, synthesis, pharmacological characterization of a fluorescent agonist of the P2Y 14 receptor

The P2Y14R is a G(i/o)-coupled receptor of the P2Y family of purinergic receptors that is activated by extracellular UDP and UDP-glucose (UDPG). In an earlier report we described a P2Y14R fluorescent probe, MRS4174, based on the potent and selective antagonist PPTN, a naphthoic acid derivative. Here, we report the design, preparation, and activity of an agonist-based fluorescent probe MRS4183 (11) and a shorter P2Y14R agonist congener, which contain a UDP-glucuronic acid pharmacophore and BODIPY fluorophores conjugated through diaminoalkyl linkers. The design relied on both docking in a P2Y14R homology model and established structure activity relationship (SAR) of nucleotide analogs. 11 retained P2Y14R potency with EC50 value of 0.96 nM (inhibition of adenylyl cyclase), compared to parent UDPG (EC50 47 nM) and served as a tracer for microscopy and flow cytometry, displaying minimal nonspecific binding. Binding saturation analysis gave an apparent binding constant for 11 in whole cells of 21.4±1.1 nM, with a t1/2 of association at 50 nM 11 of 23.9 min. Known P2Y14R agonists and PPTN inhibited cell binding of 11 with the expected rank order of potency. The success in the identification of a new P2Y14R fluorescent agonist with low nonspecific binding illustrates the advantages of rational design based on recently determined GPCR X-ray structures. Such conjugates will be useful tools in expanding the SAR of this receptor, which still lacks chemical diversity in its collective ligands

Accelerating Drug Discovery Efforts for Trypanosomatidic Infections Using an Integrated Transnational Academic Drug Discovery Platform

According to the World Health Organization, more than 1 billion people are at risk of or are affected by neglected tropical diseases. Examples of such diseases include trypanosomiasis, which causes sleeping sickness; leishmaniasis; and Chagas disease, all of which are prevalent in Africa, South America, and India. Our aim within the New Medicines for Trypanosomatidic Infections project was to use (1) synthetic and natural product libraries, (2) screening, and (3) a preclinical absorption, distribution, metabolism, and excretion\u2013toxicity (ADME-Tox) profiling platform to identify compounds that can enter the trypanosomatidic drug discovery value chain. The synthetic compound libraries originated from multiple scaffolds with known antiparasitic activity and natural products from the Hypha Discovery MycoDiverse natural products library. Our focus was first to employ target-based screening to identify inhibitors of the protozoan Trypanosoma brucei pteridine reductase 1 (TbPTR1) and second to use a Trypanosoma brucei phenotypic assay that made use of the T. brucei brucei parasite to identify compounds that inhibited cell growth and caused death. Some of the compounds underwent structure-activity relationship expansion and, when appropriate, were evaluated in a preclinical ADME-Tox assay panel. This preclinical platform has led to the identification of lead-like compounds as well as validated hits in the trypanosomatidic drug discovery value chain

Cashew Nut Shell Liquid (CNSL) as a Source of Drugs for Alzheimer’s Disease

Alzheimer’s disease (AD) is a complex neurodegenerative disorder with a multifaceted pathogenesis. This fact has long halted the development of effective anti-AD drugs. Recently, a therapeutic strategy based on the exploitation of Brazilian biodiversity was set with the aim of discovering new disease-modifying and safe drugs for AD. In this review, we will illustrate our efforts in developing new molecules derived from Brazilian cashew nut shell liquid (CNSL), a natural oil and a byproduct of cashew nut food processing, with a high content of phenolic lipids. The rational modification of their structures has emerged as a successful medicinal chemistry approach to the development of novel anti-AD lead candidates. The biological profile of the newly developed CNSL derivatives towards validated AD targets will be discussed together with the role of these molecular targets in the context of AD pathogenesis

Triazole derivatives as P2Y14 receptor antagonists

Described are compounds, which are antagonists of the P2Y14 receptor, for example, a compound of formula (I) in which ring A, R1,R2, R3, and n are as described herein. Also provided are dendron conjugates comprising the compounds, and methods of using the compounds, including a method of treating a disorder, such as inflammation, diabetes, insulin resistance, hyperglycemia, a lipid disorder, obesity, a condition associated with metabolic syndrome, and asthma, and a method of antagonizing P214 receptor activity in a cell

TRIAZOLE DERIVATIVES AS P2Y14 RECEPTOR ANTAGONISTS

The Molecular Recognition Section of NIDDK announces the availability of a novel triazole-based probes, structures which act as antagonists at human P2Y14 receptors. Although the physiologic functions of this receptor remain undefined, recently it has been strongly implicated in immune and inflammatory responses. Prior work with a 4,7-disubstituted 2 naphthoic acid derivative (PPTN) established the ability to inhibit chemotaxis of human neutrophils in the lung and kidney. In this series, the triazole moiety is used as a bioisosteric replacement for the naphthoic acid core of PPTN. This substitution imparts more stability. This triazole ring has increased polarity and additional H-bond accepting groups when compared to a naphthalene core. The new triazole scaffold can form additional interactions that stabilize the ligand within the receptor binding pocket. It has also been identified that substitution at the para-position of the phenyl ring is favored