Discovery of simplified benzazole fragments derived from the marine benzosceptrin B as necroptosis inhibitors involving the receptor interacting protein Kinase-1

Discovery of phenylisoxazolidine analogs targeting receptor interacting protein kinase 1 with anti-inflammatory activity

Receptor Interacting Protein Kinase1 (RIPK1) is a key regulator of necroptosis and plays an important role in various inflammatory signaling and cell death processes. GSK963 has been reported to inhibit RIPK1 with limited anti-necroptotic effect. We designed and prepared a series of phenylisoxazolidine analogs based on GSK963 to improve their anti-necroptotic activity. After several turns of structure activity relationship (SAR) studies, compound 22, encoded with KWML-22, was found to have good anti-necroptotic activity (EC50 = 30.0 nM) and enzymatic activity (IC50 = 6.9 nM) against RIPK1. In a TNF-α-induced inflammation in vivo model, a dose of 10 mg/kg protected mice from hypothermia and death. Our results suggest that 22 is a promising lead compound for the study of inflammatory diseases.

RIPK1 inhibitors: A key to unlocking the potential of necroptosis in drug development

Within the field of medical science, there is a great deal of interest in investigating cell death pathways in the hopes of discovering new drugs. Over the past two decades, pharmacological research has focused on necroptosis, a cell death process that has just been discovered. Receptor-interacting protein kinase 1 (RIPK1), an essential regulator in the cell death receptor signalling pathway, has been shown to be involved in the regulation of important events, including necrosis, inflammation, and apoptosis. Therefore, researching necroptosis inhibitors offers novel ways to treat a variety of disorders that are not well-treated by the therapeutic medications now on the market. The research and medicinal potential of RIPK1 inhibitors, a promising class of drugs, are thoroughly examined in this study. The journey from the discovery of Necrostatin-1 (Nec-1) to the recent advancements in RIPK1 inhibitors is marked by significant progress, highlighting the integration of traditional medicinal chemistry approaches with modern technologies like high-throughput screening and DNA-encoded library technology. This review presents a thorough exploration of the development and therapeutic potential of RIPK1 inhibitors, a promising class of compounds. Simultaneously, this review highlights the complex roles of RIPK1 in various pathological conditions and discusses potential inhibitors discovered through diverse pathways, emphasizing their efficacy against multiple disease models, providing significant guidance for the expansion of knowledge about RIPK1 and its inhibitors to develop more selective, potent, and safe therapeutic agents.

Design, Synthesis, and Evaluation of New 1H-Benzo[d]imidazole Based PqsR Inhibitors as Adjuvant Therapy for Pseudomonas aeruginosa Infections

Pseudomonas aeruginosa is one of the top priority pathogens that requires immediate attention according to the World Health Organisation (WHO). Due to the alarming shortage of novel antimicrobials, targeting quorum sensing (QS), a bacterial cell to cell signaling system controlling virulence, has emerged as a promising approach as an antibiotic adjuvant therapy. Interference with the pqs system, one of three QS systems in P. aeruginosa, results in reduction of bacterial virulence gene expression and biofilm maturation. Herein, we report a hit to lead process to fine-tune the potency of our previously reported inhibitor 1 (IC50 3.2 μM in P. aeruginosa PAO1-L), which led to the discovery of 2-(4-(3-((6-chloro-1-isopropyl-1H-benzo[d]imidazol-2-yl)amino)-2-hydroxypropoxy)phenyl)acetonitrile (6f) as a potent PqsR antagonist. Compound 6f inhibited the PqsR-controlled PpqsA-lux transcriptional reporter fusion in P. aeruginosa at low submicromolar concentrations. Moreover, 6f showed improved efficacy against P. aeruginosa CF isolates with significant inhibition of pyocyanin, 2-alkyl-4(1H)-quinolones production.

Mechanisms of PANoptosis and relevant small-molecule compounds for fighting diseases

Pyroptosis, apoptosis, and necroptosis are mainly programmed cell death (PCD) pathways for host defense and homeostasis. PANoptosis is a newly distinct inflammatory PCD pathway that is uniquely regulated by multifaceted PANoptosome complexes and highlights significant crosstalk and coordination among pyroptosis (P), apoptosis (A), and/or necroptosis(N). Although some studies have focused on the possible role of PANpoptosis in diseases, the pathogenesis of PANoptosis is complex and underestimated. Furthermore, the progress of PANoptosis and related agonists or inhibitors in disorders has not yet been thoroughly discussed. In this perspective, we provide perspectives on PANoptosome and PANoptosis in the context of diverse pathological conditions and human diseases. The treatment targeting on PANoptosis is also summarized. In conclusion, PANoptosis is involved in plenty of disorders including but not limited to microbial infections, cancers, acute lung injury/acute respiratory distress syndrome (ALI/ARDS), ischemia-reperfusion, and organic failure. PANoptosis seems to be a double-edged sword in diverse conditions, as PANoptosis induces a negative impact on treatment and prognosis in disorders like COVID-19 and ALI/ARDS, while PANoptosis provides host protection from HSV1 or Francisella novicida infection, and kills cancer cells and suppresses tumor growth in colorectal cancer, adrenocortical carcinoma, and other cancers. Compounds and endogenous molecules focused on PANoptosis are promising therapeutic strategies, which can act on PANoptosomes-associated members to regulate PANoptosis. More researches on PANoptosis are needed to better understand the pathology of human conditions and develop better treatment.

Advances in RIPK1 kinase inhibitors

Programmed necrosis is a new modulated cell death mode with necrotizing morphological characteristics. Receptor interacting protein 1 (RIPK1) is a critical mediator of the programmed necrosis pathway that is involved in stroke, myocardial infarction, fatal systemic inflammatory response syndrome, Alzheimer's disease, and malignancy. At present, the reported inhibitors are divided into four categories. The first category is the type I ATP-competitive kinase inhibitors that targets the area occupied by the ATP adenylate ring; The second category is type Ⅱ ATP competitive kinase inhibitors targeting the DLG-out conformation of RIPK1; The third category is type Ⅲ kinase inhibitors that compete for binding to allosteric sites near ATP pockets; The last category is others. This paper reviews the structure, biological function, and recent research progress of receptor interaction protein-1 kinase inhibitors.

Nigratine as dual inhibitor of necroptosis and ferroptosis regulated cell death

Nigratine (also known as 6E11), a flavanone derivative of a plant natural product, was characterized as highly specific non-ATP competitive inhibitor of RIPK1 kinase, one of the key components of necroptotic cell death signaling. We show here that nigratine inhibited both necroptosis (induced by Tumor Necrosis Factor-α) and ferroptosis (induced by the small molecules glutamate, erastin, RSL3 or cumene hydroperoxide) with EC50 in the µM range. Taken together, our data showed that nigratine is a dual inhibitor of necroptosis and ferroptosis cell death pathways. These findings open potential new therapeutic avenues for treating complex necrosis-related diseases.

Novel insights into RIPK1 as a promising target for future Alzheimer's disease treatment

Alzheimer's disease (AD) is an intractable neurodegenerative disease showing a clinical manifestation with memory loss, cognitive impairment and behavioral dysfunction. The predominant pathological characteristics of AD include neuronal loss, β-amyloid (Aβ) deposition and hyperphosphorylated Tau induced neurofibrillary tangles (NFTs), while considerable studies proved these could be triggered by neuronal death and neuroinflammation. Receptor-interacting protein kinase 1 (RIPK1) is a serine/threonine kinase existed at the cross-point of cell death and inflammatory signaling pathways. Emerging investigations have shed light on RIPK1 for its potential role in AD progression. The present review makes a bird's eye view on the functions of RIPK1 and mainly focus on the underlying linkages between RIPK1 and AD from comprehensive aspects including neuronal death, Aβ and Tau, inflammasome activation, BBB rupture, AMPK/mTOR, mitochondrial dysfunction and O-glcNAcylation. Moreover, the discovery of RIPK1 inhibitors, ongoing clinical trials along with future RIPK1-targeted therapeutics are also reviewed.

From Synthetic Simplified Marine Metabolite Analogues to New Selective Allosteric Inhibitor of Aurora B Kinase

Significant inhibition of Aurora B was achieved by the synthesis of simplified fragments of benzosceptrins and oroidin belonging to the marine pyrrole-2-aminoimidazoles metabolites isolated from sponges. Evaluation of kinase inhibition enabled the discovery of a synthetically accessible rigid acetylenic structural analogue EL-228 (1), whose structure could be optimized into the potent CJ2-150 (37). Here we present the synthesis of new inhibitors of Aurora B kinase, which is an important target for cancer therapy through mitosis regulation. The biologically oriented synthesis yielded several nanomolar inhibitors. The optimized compound CJ2-150 (37) showed a non-ATP competitive allosteric mode of action in a mixed-type inhibition for Aurora B kinase. Molecular docking identified a probable binding mode in the allosteric site "F" and highlighted the key interactions with the protein. We describe the improvement of the inhibitory potency and specificity of the novel scaffold as well as the characterization of the mechanism of action.