Highly potent dipeptidyl peptidase 8/9 (DPP8/9) inhibitors designed via relative binding free energy calculations.

Dipeptidyl peptidases (DPP) 8 and 9 are emerging enzymatic drug targets with suggested applications in acute myeloid leukaemia and HIV infection, among others. In this work, we optimised a well-known reference DPP8/9 inhibitor named 1G244, using relative binding free energy calculations. An initial retrospective, computational analysis of experimental structure-activity data of 1G244 and close structural analogues, guided the subsequent prospective design of novel inhibitors derived from the reference scaffold.

Synthesis and Application of Activity-Based Probes for Serine Proteases.

Activity-based probes (ABPs) are chemical molecules that covalently react with the active form of the targeted enzyme. These probes are useful for target and biomarker identification, as well as drug discovery. This chapter describes the creation of an ABP library tailored to serine proteases, featuring a bioorthogonal tag and a range of diphenyl phosphonate warheads to improve selectivity and reactivity.

Human Transmembrane Serine Protease 2 (TMPRSS2) on Human Seminal Fluid Extracellular Vesicles Is Proteolytically Active.

Human transmembrane serine protease 2 (TMPRSS2) has garnered substantial interest due to its clinical significance in various pathologies, notably its pivotal role in viral entry into host cells. The development of effective strategies to target TMPRSS2 is a current area of intense research and necessitates a consistent source of active TMPRSS2 with sufficient stability. Here, we comprehensively characterised human seminal-fluid extracellular vesicles (SF-EVs, also referred to as prostasomes), bearing a native source of surface-exposed, enzymatically active TMPRSS2 as demonstrated by high-sensitivity flow cytometry and a fluorometric activity assay.

Oxazole-Based Ferroptosis Inhibitors with Promising Properties to Treat Central Nervous System Diseases.

Ferroptosis plays an important role in the occurrence and development of many diseases, including neurodegenerative diseases. Thus, ferroptosis inhibitors able to cross the blood-brain barrier may have therapeutic potential. The best ferroptosis inhibitors so far are lipophilic radical trapping antioxidants (RTAs) that block lipid peroxidation in membranes.

Intrinsic temperature increase drives lipid metabolism towards ferroptosis evasion and chemotherapy resistance in pancreatic cancer.

A spontaneously occurring temperature increase in solid tumors has been reported sporadically, but is largely overlooked in terms of cancer biology. Here we show that temperature is increased in tumors of patients with pancreatic ductal adenocarcinoma (PDAC) and explore how this could affect therapy response. By mimicking this observation in PDAC cell lines, we demonstrate that through adaptive changes in lipid metabolism, the temperature increase found in human PDAC confers protection to lipid peroxidation and contributes to gemcitabine resistance.

Ferroptosis is a targetable detrimental factor in metabolic dysfunction-associated steatotic liver disease.

There is an unmet clinical need for pharmacologic treatment for metabolic dysfunction-associated steatotic liver disease (MASLD). Hepatocyte cell death is a hallmark of this highly prevalent chronic liver disease, but the dominant type of cell death remains uncertain. Here we report that ferroptosis, an iron-catalyzed mode of regulated cell death, contributes to MASLD.

Trans-cyclooctene-a Swiss army knife for bioorthogonal chemistry: exploring the synthesis, reactivity, and applications in biomedical breakthroughs.

Background: Trans-cyclooctenes (TCOs) are highly strained alkenes with remarkable reactivity towards tetrazines (Tzs) in inverse electron-demand Diels-Alder reactions. Since their discovery as bioorthogonal reaction partners, novel TCO derivatives have been developed to improve their reactivity, stability, and hydrophilicity, thus expanding their utility in diverse applications.

Main Body: TCOs have garnered significant interest for their applications in biomedical settings.

Design and Synthesis of 1,3-Diarylpyrazoles and Investigation of Their Cytotoxicity and Antiparasitic Profile.

Herein, we report a series of 1,3-diarylpyrazoles that are analogues of compound /HIT 8. We previously identified this molecule as a 'hit' during a high-throughput screening campaign for autophagy inducers. A variety of synthetic strategies were utilized to modify the 1,3-diarylpyrazole core at its 1-, 3-, and 4-position.

Druglike, F-labeled PET Tracers Targeting Fibroblast Activation Protein.

Fibroblast activation protein (FAP) is a very reliable biomarker for tissue remodeling. FAP has so far mainly been studied in oncology, but there is growing interest in the enzyme in other diseases like fibrosis. Recently, FAP-targeting diagnostics and therapeutics have emerged, of which the so-called FAPIs are among the most promising representatives.

Active site-directed probes targeting dipeptidyl peptidases 8 and 9.

Dipeptidyl peptidases (DPP) 8 and 9 are intracellular serine proteases that play key roles in various biological processes and recent findings highlight DPP8 and DPP9 as potential therapeutic targets for hematological and inflammasome-related diseases. Despite the substantial progress, the precise biological functions of these proteases remain elusive, and the lack of selective chemical tools hampers ongoing research. In this paper, we describe the synthesis and biochemical evaluation of the first active site-directed DPP8/9 probes which are derived from DPP8/9 inhibitors developed in-house.

A high-throughput target-based screening approach for the identification and assessment of mycothione reductase inhibitors.

Unlabelled: The World Health Organization's goal to combat tuberculosis (TB) is hindered by the emergence of anti-microbial resistance, therefore necessitating the exploration of new drug targets. Multidrug regimens are indispensable in TB therapy as they provide synergetic bactericidal effects, shorten treatment duration, and reduce the risk of resistance development. The research within our European RespiriTB consortium explores energy metabolism to identify new drug candidates that synergize with bedaquiline, with the aim of discovering more efficient combination drug regimens.

Characterization of Structurally Diverse F-Labeled d-TCO Derivatives as a PET Probe for Bioorthogonal Pretargeted Imaging.

The pretargeted imaging strategy using inverse electron demand Diels-Alder (IEDDA) cycloaddition between a -cyclooctene (TCO) and tetrazine (Tz) has emerged and rapidly grown as a promising concept to improve radionuclide imaging and therapy in oncology. This strategy has mostly relied on the use of radiolabeled Tz together with TCO-modified targeting vectors leading to a rapid growth of the number of available radiolabeled tetrazines, while only a few radiolabeled TCOs are currently reported. Here, we aim to develop novel and structurally diverse F-labeled cis-dioxolane-fused TCO (d-TCO) derivatives to further expand the bioorthogonal toolbox for ligation and evaluate their potential for positron emission tomography (PET) pretargeted imaging.

Highly Selective Inhibitors of Dipeptidyl Peptidase 9 (DPP9) Derived from the Clinically Used DPP4-Inhibitor Vildagliptin.

Dipeptidyl peptidase 9 (DPP9) is a proline-selective serine protease that plays a key role in NLRP1- and CARD8-mediated inflammatory cell death (pyroptosis). No selective inhibitors have hitherto been reported for the enzyme: all published molecules have grossly comparable affinities for DPP8 and 9 because of the highly similar architecture of these enzymes' active sites. Selective DPP9 inhibitors would be highly instrumental to address unanswered research questions on the enzyme's role in pyroptosis, and they could also be investigated as therapeutics for acute myeloid leukemias.

Ferroptosis contributes to multiple sclerosis and its pharmacological targeting suppresses experimental disease progression.

Multiple sclerosis (MS) is a chronic autoimmune disorder characterized by central nervous (CNS) demyelination resulting in axonal injury and neurological deficits. Essentially, MS is driven by an auto-amplifying mechanism of inflammation and cell death. Current therapies mainly focus on disease modification by immunosuppression, while no treatment specifically focuses on controlling cell death injury.

Effect of erythrophagocytosis-induced ferroptosis during angiogenesis in atherosclerotic plaques.

Intraplaque (IP) angiogenesis is a key feature of advanced atherosclerotic plaques. Because IP vessels are fragile and leaky, erythrocytes are released and phagocytosed by macrophages (erythrophagocytosis), which leads to high intracellular iron content, lipid peroxidation and cell death. In vitro experiments showed that erythrophagocytosis by macrophages induced non-canonical ferroptosis, an emerging type of regulated necrosis that may contribute to plaque destabilization.

From PERK to RIPK1: Design, synthesis and evaluation of novel potent and selective necroptosis inhibitors.

Receptor-Interacting serine/threonine-Protein Kinase 1 (RIPK1) emerged as an important driver of inflammation and, consequently, inflammatory pathologies. The enzymatic activity of RIPK1 is known to indirectly promote inflammation by triggering cell death, in the form of apoptosis, necroptosis and pyroptosis. Small molecule Receptor-Interacting serine/threonine-Protein Kinase 1 inhibitors have therefore recently entered clinical trials for the treatment of a subset of inflammatory pathologies.

Chemically diverse activity-based probes with unexpected inhibitory mechanisms targeting trypsin-like serine proteases.

Activity-based probes (ABP) are molecules that bind covalently to the active form of an enzyme family, making them an attractive tool for target and biomarker identification and drug discovery. The present study describes the synthesis and biochemical characterization of novel activity-based probes targeting trypsin-like serine proteases. We developed an extensive library of activity-based probes with "clickable" affinity tags and a diaryl phosphonate warhead.

A Novel Ferroptosis Inhibitor UAMC-3203, a Potential Treatment for Corneal Epithelial Wound.

Corneal wound, associated with pain, impaired vision, and even blindness, is the most common ocular injury. In this study, we investigated the effect of a novel ferroptosis inhibitor, UAMC-3203 (10 nM-50 µM), in corneal epithelial wound healing in vitro in human corneal epithelial (HCE) cells and ex vivo using alkali-induced corneal wounded mice eye model. We evaluated in vivo acute tolerability of the compound by visual inspection, optical coherence tomography (OCT), and stereomicroscope imaging in rats after its application (100 µM drug solution in phosphate buffer pH 7.

The Potential Role of Regulated Cell Death in Dry Eye Diseases and Ocular Surface Dysfunction.

The research on new treatments for dry eye diseases (DED) has exponentially grown over the past decades. The increased prevalence of dry eye conditions, particularly in the younger population, has received much attention. Therefore, it is of utmost importance to identify novel therapeutical targets.

Proteases and Their Potential Role as Biomarkers and Drug Targets in Dry Eye Disease and Ocular Surface Dysfunction.

Dry eye disease (DED) is a multifactorial disorder that leads to ocular discomfort, visual disturbance, and tear film instability. DED is accompanied by an increase in tear osmolarity and ocular surface inflammation. The diagnosis and treatment of DED still present significant challenges.

Vildagliptin-Derived Dipeptidyl Peptidase 9 (DPP9) Inhibitors: Identification of a DPP8/9-Specific Lead.

Vildagliptin is a marketed DPP4 inhibitor, used in the management of type 2 diabetes. The molecule also has notable DPP8/9 affinity, with some preference for DPP9. Therefore, we aimed to use vildagliptin as a starting point for selective DPP8/9 inhibitors, and to engineer out the parent compound's DPP4-affinity.

The Effect of Serine Protease Inhibitors on Visceral Pain in Different Rodent Models With an Intestinal Insult.

Serine proteases are believed to play a key role in the origin of abdominal pain in IBD and IBS. We previously demonstrated a reduction of visceral pain in a post-inflammatory IBS rat model after a single intraperitoneal or intracolonic administration of a serine protease inhibitor. The aim of this study was to investigate the efficacy of serine protease inhibition on visceral pain in two different animal models involving a colonic insult based either on acute inflammation or on neonatal irritation.