Characterization of RNA driven structural changes in full length RIG-I leading to its agonism or antagonism.

RIG-I (retinoic acid inducible gene-I) can sense subtle differences between endogenous and viral RNA in the cytoplasm, triggering an anti-viral immune response through induction of type I interferons (IFN) and other inflammatory mediators. Multiple crystal and cryo-EM structures of RIG-I suggested a mechanism in which the C-terminal domain (CTD) is responsible for the recognition of viral RNA with a 5'-triphoshate modification, while the CARD domains serve as a trigger for downstream signaling, leading to the induction of type I IFN. However, to date contradicting conclusions have been reached around the role of ATP in the mechanism of the CARD domains ejection from RIG-I's autoinhibited state. Here we present an application of NMR spectroscopy to investigate changes induced by the binding of 5'-triphosphate and 5'-OH dsRNA, both in the presence and absence of nucleotides, to full length RIG-I with all its methionine residues selectively labeled (Met-[ϵ-13CH3]). With this approach we were able to identify residues on the CTD, helicase domain, and CARDs that served as probes to sense RNA-induced conformational changes in those respective regions. Our results were analyzed in the context of either agonistic or antagonistic RNAs, by and large supporting a mechanism proposed by the Pyle Lab in which CARD release is primarily dependent on the RNA binding event.

Efficacy and safety of modified Xiao-Feng Powder in the treatment of chronic urticaria: protocol of a randomized double-blind placebo-controlled study.

BACKGROUND: Chronic Urticaria (CU), a common skin disorder known as Yin Zhen in Chinese medicine, is characterized by recurrent, pruritic, pink-to-red edematous lesions and wheals on the skin. Xiao-Feng Powder (XFP, meaning Wind-Dispersing Powder), is reported to be one of the most frequently used Chinese herbal formulae for CU. In this study, we aim to investigate the effectiveness and safety of modified Xiao-Feng Powder (mXFP) for the treatment of CU. METHODS: In this randomised double-blind placebo-controlled clinical trial, 58 subjects identified as having mild to severe urticaria (Urticaria activity score greater than 10) will be recruited and randomised into two groups to receive antihistamine Bilastine with either mXFP or placebo for 12 weeks, followed by post treatment visits at week 16. The primary outcome measure is the change of weekly urticaria activity score (UAS7) at week 12. Secondary outcome measures include the Urticaria Control Test (UCT), Visual Analog Scale of Itch Severity (VAS), Chronic Urticaria Quality of Life Questionnaire (CU-Q2oL), Angioedema Activity Score (AAS), immunoglobulin E (IgE) test, gut microbiota test and use of antihistamines during study period. The trial will be conducted at three Chinese medicine clinics in Hong Kong. EXPECTED OUTCOMES: The results of this study will establish robust clinical evidence about the efficacy and safety of mXFP in the treatment of CU. A specific feature of this trial is that it is a integrative medicine trial with subjects being allowed to take the Western and Chinese medicine together for the treatment. Trial registration This is registered on ClinicalTrials.gov, ID: NCT04967092. Register date: July 19, 2021. https://clinicaltrials.gov/ct2/show/NCT04967092 .

Discovery of MK-1454: A Potent Cyclic Dinucleotide Stimulator of Interferon Genes Agonist for the Treatment of Cancer.

Stereochemically and structurally complex cyclic dinucleotide-based stimulator of interferon genes (STING) agonists were designed and synthesized to access a previously unexplored chemical space. The assessment of biochemical affinity and cellular potency, along with computational, structural, and biophysical characterization, was applied to influence the design and optimization of novel STING agonists, resulting in the discovery of MK-1454 as a molecule with appropriate properties for clinical development. When administered intratumorally to immune-competent mice-bearing syngeneic tumors, MK-1454 exhibited robust tumor cytokine upregulation and effective antitumor activity. Tumor shrinkage in mouse models that are intrinsically resistant to single-agent therapy was further enhanced when treating the animals with MK-1454 in combination with a fully murinized antimouse PD-1 antibody, mDX400. These data support the development of STING agonists in combination with pembrolizumab (humanized anti-PD-1 antibody) for patients with tumors that are partially responsive or nonresponsive to single-agent anti-PD-1 therapy.

The efficacy and safety of Yupingfeng Powder with variation in the treatment of allergic rhinitis: Study protocol for a randomized, double-blind, placebo-controlled trial.

Background: Allergic rhinitis (AR) is an upper airways chronic inflammatory disease mediated by IgE, which affects 10%-20% of the population. The mainstay for allergic rhinitis nowadays include steroids and antihistamines, but their effects are less than ideal. Many patients therefore seek Chinese medicine for treatment and Yupingfeng Powder is one of the most common formulae prescribed. In this study, we aim to investigate the efficacy and safety of Yupingfeng Powder with variation for the treatment of allergic rhinitis. Study design: This is a double-blind, randomized, placebo-controlled trial. A 2-week screening period will be implemented, and then eligible subjects with allergic rhinitis will receive interventions of either "Yupingfeng Powder with variation" granules or placebo granules for 8 weeks, followed by post treatment visits at weeks 12 and 16. The change in the Total Nasal Symptom Score (TNSS) will be used as the primary outcome. Discussion: This trail will evaluate the efficacy and safety of Yupingfeng Powder in treating allergic rhinitis. The study may provide the solid evidence of Yupingfeng Powder with variation can produce better clinical efficacy than the placebo granules. Trial registration: ClinicalTrials.gov, identifier NCT04976023.

Discovery of a Novel cGAMP Competitive Ligand of the Inactive Form of STING.

Drugging large protein pockets is a challenge due to the need for higher molecular weight ligands, which generally possess undesirable physicochemical properties. In this communication, we highlight a strategy leveraging small molecule active site dimers to inhibit the large symmetric binding pocket in the STING protein. By taking advantage of the 2:1 binding stoichiometry, maximal buried interaction with STING protein can be achieved while maintaining the ligand physicochemical properties necessary for oral exposure. This mode of binding requires unique considerations for potency optimization including simultaneous optimization of protein-ligand as well as ligand-ligand interactions. Successful implementation of this strategy led to the identification of 18, which exhibits good oral exposure, slow binding kinetics, and functional inhibition of STING-mediated cytokine release.

The Discovery of 3-((4-Chloro-3-methoxyphenyl)amino)-1-((3R,4S)-4-cyanotetrahydro-2H-pyran-3-yl)-1H-pyrazole-4-carboxamide, a Highly Ligand Efficient and Efficacious Janus Kinase 1 Selective Inhibitor with Favorable Pharmacokinetic Properties.

The discovery of a potent selective low dose Janus kinase 1 (JAK1) inhibitor suitable for clinical evaluation is described. As part of an overall goal to minimize dose, we pursued a medicinal chemistry strategy focused on optimization of key parameters that influence dose size, including lowering human Clint and increasing intrinsic potency, bioavailability, and solubility. To impact these multiple parameters simultaneously, we used lipophilic ligand efficiency as a key metric to track changes in the physicochemical properties of our analogs, which led to improvements in overall compound quality. In parallel, structural information guided advancements in JAK1 selectivity by informing on new vector space, which enabled the discovery of a unique key amino acid difference between JAK1 (Glu966) and JAK2 (Asp939). This difference was exploited to consistently produce analogs with the best balance of JAK1 selectivity, efficacy, and projected human dose, ultimately culminating in the discovery of compound 28.

Structure-based design and development of (benz)imidazole pyridones as JAK1-selective kinase inhibitors.

The mammalian Janus Kinases (JAK1, JAK2, JAK3 and TYK2) are intracellular, non-receptor tyrosine kinases whose activities have been associated in the literature and the clinic with a variety of hyperproliferative diseases and immunological disorders. At the onset of the program, it was hypothesized that a JAK1 selective compound over JAK2 could lead to an improved therapeutic index relative to marketed non-selective JAK inhibitors by avoiding the clinical AEs, such as anemia, presumably associated with JAK2 inhibition. During the course of the JAK1 program, a number of diverse chemical scaffolds were identified from both uHTS campaigns and de novo scaffold design. As part of this effort, a (benz)imidazole scaffold evolved via a scaffold-hopping exercise from a mature chemical series. Concurrent crystallography-driven exploration of the ribose pocket and the solvent front led to analogs with optimized kinome and JAK1 selectivities over the JAK2 isoform by targeting several residues unique to JAK1, such as Arg-879 and Glu-966.

The discovery of reverse tricyclic pyridone JAK2 inhibitors. Part 2: lead optimization.

This communication discusses the discovery of novel reverse tricyclic pyridones as inhibitors of Janus kinase 2 (JAK2). By using a kinase cross screening approach coupled with molecular modeling, a unique inhibitor-water interaction was discovered to impart excellent broad kinase selectivity. Improvements in intrinsic potency were achieved by utilizing a rapid library approach, while targeted structural changes to lower lipophilicity led to improved rat pharmacokinetics. This multi-pronged approach led to the identification of 31, which demonstrated encouraging rat pharmacokinetics, in vivo potency, and excellent off-target kinase selectivity.

The discovery of tricyclic pyridone JAK2 inhibitors. Part 1: hit to lead.

This paper describes the discovery and design of a novel class of JAK2 inhibitors. Furthermore, we detail the optimization of a screening hit using ligand binding efficiency and log D. These efforts led to the identification of compound 41, which demonstrates in vivo activity in our study.

Allosteric inhibitors of Akt1 and Akt2: discovery of [1,2,4]triazolo[3,4-f][1,6]naphthyridines with potent and balanced activity.

A series of [1,2,4]triazolo[3,4-f][1,6]naphthyridine allosteric dual inhibitors of Akt1 and 2 have been developed. These compounds have been shown to have potent dual Akt1 and 2 cell potency. The representative compound 13 provided potent inhibitory activity against Akt1 and 2 in vivo in a mouse model.

Discovery of potent and cell-active allosteric dual Akt 1 and 2 inhibitors.

This paper describes the improvement of cell potency in a class of allosteric Akt 1 and 2 inhibitors. Key discoveries include identifying the solvent exposed region of the molecule and appending basic amines to enhance the physiochemical properties of the molecules. Findings from the structure-activity relationships are discussed.

The design and synthesis of potent and cell-active allosteric dual Akt 1 and 2 inhibitors devoid of hERG activity.

This letter details the attenuation of hERG in a class of Akt inhibitors through heteroatom insertions into aromatic rings. The development of a cell-active dual Akt 1 and 2 inhibitors devoid of hERG activity is discussed using structure-activity relationships.