Inhibitory Effects of Secondary Metabolites and Their Synthetic Derivatives against SARS-CoV-2 M and NS2B/NS3 (ZIKV and DENV-2).

Chemical studies of twigs yielded two compounds, identified as taraxerol () and methyl gallate (). The galloyl moiety was suggested as a potential scaffold that can interfere with proteases by previous biological investigations on SARS-CoV-2 main protease (M) inhibitors in combination with docking studies. Therefore, a series of 13 gallate esters were prepared by treating gallic acid with natural and non-natural alcohols.

Profiling Cysteine Proteases Activities in Neuroinflammatory Cells.

A new activity-based probe (ABP) of cysteine proteases (FGA139) has been designed and synthesized. The design of the ABP has been done based upon the chemical structure of an irreversible inhibitor of cysteine proteases by attaching a bodipy fluorophore at the N-terminus of the peptide backbone. The synthetic route of the probe has a metathesis and a "click" reaction as key steps.

Bacteria from the Amycolatopsis genus associated with a toxic bird secrete protective secondary metabolites.

Uropygial gland secretions of birds consist of host and bacteria derived compounds and play a major sanitary and feather-protective role. Here we report on our microbiome studies of the New Guinean toxic bird Pachycephala schlegelii and the isolation of a member of the Amycolatopsis genus from the uropygial gland secretions. Bioactivity studies in combination with co-cultures, MALDI imaging and HR-MS/MS-based network analyses unveil the basis of its activity against keratinolytic bacteria and fungal skin pathogens.

Rhodesain inhibitors on the edge of reversibility-irreversibility.

A comparative study of Michael acceptor and keto-Michael acceptor inhibitors of the cysteine protease rhodesain has been performed. Five new inhibitors have been prepared bearing the peptide structure of the known cysteine protease inhibitor K11777 and differing on the warhead. For the preparation of the Michael acceptor warhead, a Horner-Wadsworth-Emmons reaction was used.

Zika virus replication is impaired by a selective agonist of the TRPML2 ion channel.

The flavivirus genus includes human pathogenic viruses such as Dengue (DENV), West Nile (WNV) and Zika virus (ZIKV) posing a global health threat due to limited treatment options. Host ion channels are crucial for various viral life cycle stages, but their potential as targets for antivirals is often not fully realized due to the lack of selective modulators. Here, we observe that treatment with ML2-SA1, an agonist for the human endolysosomal cation channel TRPML2, impairs ZIKV replication.

Structure-Based Design and Synthesis of Covalent Inhibitors for Deubiquitinase and Acetyltransferase ChlaDUB1 of .

Upon infection by an intracellular pathogen, host cells activate apoptotic pathways to limit pathogen replication. Consequently, efficient proliferation of the obligate intracellular pathogen , a major cause of trachoma and sexually transmitted diseases, depends on the suppression of host cell apoptosis. secretes deubiquitinase ChlaDUB1 into the host cell, leading among other interactions to the stabilization of antiapoptotic proteins and, thus, suppression of host cell apoptosis.

Structural Modifications of Covalent Cathepsin S Inhibitors: Impact on Affinity, Selectivity, and Permeability.

Cathepsin S (catS) is a member of the cysteine protease family with limited tissue distribution, which is predominantly found in antigen-presenting cells. Due to overexpression and overactivity of catS in numerous cancers, inhibition of catS is supposed to improve the antitumor response. Here, we explore the potential of small-molecule catS inhibitors emphasizing their in vitro pharmacodynamics and pharmacokinetics.

Substitution-Induced Mechanistic Switching in SAr-Warheads for Cysteine Proteases.

The aim of this study was to investigate the transition from non-covalent reversible over covalent reversible to covalent irreversible inhibition of cysteine proteases by making delicate structural changes to the warhead scaffold. To this end, dipeptidic rhodesain inhibitors with different -terminal electrophilic arenes as warheads relying on the SAr mechanism were synthesized and investigated. Strong structure-activity relationships of the inhibition potency, the degree of covalency, and the reversibility of binding on the arene substitution pattern were found.

Identification of Dual Inhibitors Targeting Main Protease (M) and Cathepsin L as Potential Anti-SARS-CoV-2 Agents.

In this structure-activity relationship (SAR) study, we report the development of dual inhibitors with antiviral properties targeting the SARS-CoV-2 main protease (M) and human cathepsin L (hCatL). The novel molecules differ in the aliphatic amino acids at the P2 site and the fluorine position on the phenyl ring at the P3 site. The identified dual inhibitors showed values within 1.

Dual Strategy to Design New Agents Targeting : Advancing Phenotypic and CB1 Inhibitors for Improved Efficacy.

In this study, we have identified and optimized two lead structures from an in-house screening, with promising results against the parasitic flatworm and its target protease cathepsin B1 (CB1). Our correlation analysis highlighted the significance of physicochemical properties for the compounds' in vitro activities, resulting in a dual approach to optimize the lead structures, regarding both phenotypic effects in newly transformed schistosomula (NTS), adult worms, and CB1 inhibition. The optimized compounds from both approaches ("phenotypic" vs "CB1" approach) demonstrated improved efficacy against NTS and adult worms, with from the "CB1" approach emerging as the most potent compound.

Development of Novel Peptidyl Nitriles Targeting Rhodesain and Falcipain-2 for the Treatment of Sleeping Sickness and Malaria.

In recent decades, neglected tropical diseases and poverty-related diseases have become a serious health problem worldwide. Among these pathologies, human African trypanosomiasis, and malaria present therapeutic problems due to the onset of resistance, toxicity problems and the limited spectrum of action. In this drug discovery process, rhodesain and falcipain-2, of and , are currently considered the most promising targets for the development of novel antitrypanosomal and antiplasmodial agents, respectively.

Ligand-Based Design of Selective Peptidomimetic uPA and TMPRSS2 Inhibitors with Arg Bioisosteres.

Trypsin-like serine proteases are involved in many important physiological processes like blood coagulation and remodeling of the extracellular matrix. On the other hand, they are also associated with pathological conditions. The urokinase-pwlasminogen activator (uPA), which is involved in tissue remodeling, can increase the metastatic behavior of various cancer types when overexpressed and dysregulated.

Peptidyl nitroalkene inhibitors of main protease rationalized by computational and crystallographic investigations as antivirals against SARS-CoV-2.

The coronavirus disease 2019 (COVID-19) pandemic continues to represent a global public health issue. The viral main protease (M) represents one of the most attractive targets for the development of antiviral drugs. Herein we report peptidyl nitroalkenes exhibiting enzyme inhibitory activity against M (K: 1-10 μM) good anti-SARS-CoV-2 infection activity in the low micromolar range (EC: 1-12 μM) without significant toxicity.

Investigating the Cytotoxicity of Ru(II) Polypyridyl Complexes by Changing the Electronic Structure of Salicylaldehyde Ligands.

A novel class of Ru(II)-based polypyridyl complexes with an auxiliary salicylaldehyde ligand [Ru(phen)(X-Sal)]BF {X: H (), 5-Cl (), 5-Br (), 3,5-Cl (), 3,5-Br (), 3-Br,5-Cl (), 3,5-I (), 5-NO (), 5-Me (), 4-Me (), 4-OMe (), and 4-DEA (), has been synthesized and characterized by elemental analysis, FT-IR, and H/C NMR spectroscopy. The molecular structure of , , , , and was determined by single-crystal X-ray diffraction analysis which revealed structural similarities. DFT and TD-DFT calculations showed that they also possess similar electronic structures.

Designing photoaffinity tool compounds for the investigation of the DENV NS2B-NS3 protease allosteric binding pocket.

Dengue virus (DENV) infection still lacks specific antiviral therapy, making the NS2B-NS3 protease an attractive target for drug development. However, allosteric inhibitors that bind to a site other than the active site still need to be better understood. In this study, we designed and synthesised tool compounds for photoaffinity labelling (PAL) to investigate the binding site of allosteric inhibitors on the DENV protease.

Protease detection in the biosensor era: A review.

Proteases have been proposed as potential biomarkers for several pathological conditions including cancers, multiple sclerosis and cardiovascular diseases, due to their ability to break down the components of extracellular matrix and basement membrane. The development of protease biosensors opened up the possibility to investigate the proteolytic activity of dysregulated proteases with higher efficiency over the traditional detection assays due to their quick detection capability, high sensitivity and selectivity, simple instrumentation and cost-effective fabrication processes. In contrast to the recently published review papers that primarily focused on one specific class of proteases or one specific detection method, this review article presents different optical and electrochemical detection methods that can be used to design biosensors for all major protease families.

Impact of the Warhead of Dipeptidyl Keto Michael Acceptors on the Inhibition Mechanism of Cysteine Protease Cathepsin L.

Cathepsin L (CatL) is a lysosomal cysteine protease whose activity has been related to several human pathologies. However, although preclinical trials using CatL inhibitors were promising, clinical trials have been unsuccessful up to now. We are presenting a study of two designed dipeptidyl keto Michael acceptor potential inhibitors of CatL with either a keto vinyl ester or a keto vinyl sulfone (KVS) warhead.

Two palladium (II) complexes derived from halogen-substituted Schiff bases and 2-picolylamine induce parthanatos-type cell death in sensitive and multi-drug resistant CCRF-CEM leukemia cells.

The use of cisplatin and its derivatives in cancer treatment triggered the interest in metal-containing complexes as potential novel anticancer agents. Palladium (II)-based complexes have been synthesized in recent years with promising antitumor activity. Previously, we described the synthesis and cytotoxicity of palladium (II) complexes containing halogen-substituted Schiff bases and 2-picolylamine.

The effects of allosteric and competitive inhibitors on ZIKV protease conformational dynamics explored through smFRET, nanoDSF, DSF, and F NMR.

Zika and dengue viruses cause mosquito-borne diseases of high epidemic relevance. The viral NS2B-NS3 proteases play crucial roles in the pathogen replication cycle and are validated drug targets. They can adopt at least two conformations depending on the position of the NS2B cofactor.

Next Generation of Fluorometric Protease Assays: 7-Nitrobenz-2-oxa-1,3-diazol-4-yl-amides (NBD-Amides) as Class-Spanning Protease Substrates.

Fluorometric assays are one of the most frequently used methods in medicinal chemistry. Over the last 50 years, the reporter molecules for the detection of protease activity have evolved from first-generation colorimetric p-nitroanilides, through FRET substrates, and 7-amino-4-methyl coumarin (AMC)-based substrates. The aim of further substrate development is to increase sensitivity and reduce vulnerability to assay interferences.

Covalent -Adenosylhomocysteine-Based DNA Methyltransferase 2 Inhibitors with a New Type of Aryl Warhead.

The DNA methyltransferase 2 (DNMT2) is an RNA modifying enzyme associated with pathophysiological processes, such as mental and metabolic disorders or cancer. Although the development of methyltransferase inhibitors remains challenging, DNMT2 is not only a promising target for drug discovery, but also for the development of activity-based probes. Here, we present covalent SAH-based DNMT2 inhibitors decorated with a new type of aryl warhead.

Inhibitory effects of 190 compounds against SARS-CoV-2 M protein: Molecular docking interactions.

COVID-19 has caused many deaths since the first outbreak in 2019. The burden on healthcare systems around the world has been reduced by the success of vaccines. However, population adherence and the occurrence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants are still challenging tasks to be affronted.

Dipeptide Nitrile CD34 with Curcumin: A New Improved Combination Strategy to Synergistically Inhibit Rhodesain of .

Rhodesain is the main cysteine protease of , the parasite causing the acute lethal form of Human African Trypanosomiasis. Starting from the dipeptide nitrile , the further introduction of a fluorine atom in the position of the phenyl ring spanning in the P3 site and the switch of the P2 leucine with a phenylalanine led to , a synthetic inhibitor that shows a nanomolar binding affinity towards rhodesain ( = 27 nM) and an improved target selectivity with respect to the parent dipeptide nitrile . In the present work, following the Chou and Talalay method, we carried out a combination study of with curcumin, a nutraceutical obtained from Starting from an affected fraction (f) of rhodesain inhibition of 0.