Bruton's Tyrosine Kinase Inhibitors with Distinct Binding Modes Reveal Differential Functional Impact on B-Cell Receptor Signaling.

Small molecule inhibitors of Bruton's tyrosine kinase (BTK) have been approved for the treatment of multiple B-cell malignancies and are being evaluated for autoimmune and inflammatory diseases. Various BTK inhibitors (BTKi) have distinct potencies, selectivity profiles, and binding modes within the ATP-binding site. On the basis of the latter feature, BTKis can be classified into those that occupy the back-pocket, H3 pocket, and the hinge region only. Hypothesizing that differing binding modes may have differential impact on the B-cell receptor (BCR) signaling pathway, we evaluated the activities of multiple BTKis in B-cell lymphoma models in vitro and in vivo. We demonstrated that, although all three types of BTKis potently inhibited BTK-Y223 autophosphorylation and phospholipase C gamma 2 (PLCγ2)-Y1217 transphosphorylation, hinge-only binders were defective in inhibiting BTK-mediated calcium mobilization upon BCR activation. In addition, PLCγ2 activation was effectively blocked by back-pocket and H3 pocket binders but not by hinge-only binders. Further investigation using TMD8 cells deficient in Rac family small GTPase 2 (RAC2) revealed that RAC2 functioned as a bypass mechanism, allowing for residual BCR signaling and PLCγ2 activation when BTK kinase activity was fully inhibited by the hinge-only binders. These data reveal a kinase activity-independent function of BTK, involving RAC2 in transducing BCR signaling events, and provide mechanistic rationale for the selection of clinical candidates for B-cell lymphoma indications.

Combinatorial inhibition of Tec kinases BTK and ITK is beneficial in ameliorating murine sclerodermatous chronic graft versus host disease.

Graft-versus-host disease (GVHD) is the major factor limiting the widespread use of potentially curative allogeneic hematopoietic stem cell transplant (allo-HSCT). Chronic GVHD is characterized by the activation of alloreactive donor immune cells, especially B- and T-cells, leading to tissue damage and pathogenic fibrosis. In this study, we used highly specific next-generation inhibitors of ITK (PCYC-274), BTK (PCYC-804), and ibrutinib-like BTK/ITK inhibitors (PCYC-914 and PCYC-401) in the B10.D2 → BALB/C model of murine sclerodermatous cGVHD. From the third week onward, allogeneic recipients in each group of respective Tec kinase inhibitors were treated three times weekly with inhibitors at doses of 10 and 30 mg/kg or with saline control via oral gavage. Overall, we found that selective BTK inhibition was less effective than combined ITK/BTK or ITK inhibition in lengthening survival and reducing symptoms of cGVHD. ITK inhibition was most efficacious, with PCYC-274 and PCYC-401 demonstrating a nearly 50 percent reduction in GVHD scoring even at the 10 mg/kg dose, while 30 mg/kg of these compounds almost completely ameliorated GVHD symptomology. BTK/ITK and ITK-treated mice showed significant reductions in overall pathology. Significant reductions in dermal thickness and fibrosis were shown for all treatment groups. There was evidence of mixed Th1 and Th2 cytokine profiles in the skin of mice with dermal cGVHD, as both IFN-gamma and IL-4 were upregulated in the allogeneic control group, while kinase inhibition significantly reduced levels of these cytokines. Using an in vitro model of T-cell polarization, Th1 cell production of TNF-alpha and IFN-gamma were partially blocked by ITK. Th2 cell production of IL-4 was almost completely blocked synergistically by ITK and BTK inhibition. BTK-specific inhibition was unable to block either Th1 or Th2 cytokine production. Taken together, these results confirm previous reports that ITK-focused inhibition inhibits Th1 and Th2 cells. Additionally, the compound's effects on T-cell proliferation were tested by CFSE assay. Pure ITK inhibition was most effective at blocking T-cell proliferation, with no proliferation in PCYC-274-treated cells even at 0.1uM. PCYC-401 and PCYC-914 showed some inhibition at lower doses, with complete inhibition evident at 10uM. PCYC-804 was only partially able to block proliferation even at 10uM. In conclusion, we observed substantial benefit for differential inhibition of Tec kinases in GVHD, with ITK being most efficacious and Th1 cells being more resistant to inhibition, matching the previously reported findings of a Th2 to Th1 selective pressure in cells treated with ibrutinib. Our data warrants the further development of ITK and ITK/BTK inhibitors with specific inhibitory ratios to improve the treatment of GVHD and other T-cell mediated diseases.

Synthesis and characterization of single-phase Tb3+/Eu3+ doped metal-organic framework phosphors for warm light WLED applications.

A novel single-phase luminescent material, Ln@bio-MOF-1 (Ln: Tb3+ and Eu3+), was synthesized by a facile hydrothermal method. The structural and luminescence characteristics of the MOF materials were studied in detail. The chromaticity of the as-prepared samples might be easily modulated using molar amounts of Tb3+ and Eu3+. Sample Tb/Eu@bio-MOF-1 (1) demonstrates a white emission (CIE coordinates: 0.328, 0.338), which is very close to the standard white light (0.333, 0.333). Tb/Eu@bio-MOF-1 (1) has a quantum yield of 52.9%, which is higher than those in most reported works. The corresponding LED devices were prepared to further explore the possible applications of Ln@bio-MOF-1 in WLEDs. The achieved LED device has a high color rendering index (CRI) of 86.2 and a low correlated color temperature (CCT) of 4725 K, which indicates that Tb/Eu@bio-MOF-1 (1) might be a feasible luminescent material for WLED applications.

Qiangli Wuhu mixture alleviates LPS-induced pneumonia by inhibiting the TLR4/NF-κB/NLRP3 pathway: a study based on network pharmacology.

CONTEXT: Qiangli Wuhu (QLWH) mixture is a concoction approved and registered by Ningxia Medical Products Administration. It has therapeutic effects on various types of pneumonia. OBJECTIVE: To clarify the mechanisms of QLWH in treating pneumonia. MATERIALS AND METHODS: The potential targets of QLWH in the treatment of pneumonia were predicted by network pharmacology. Male, Institute of Cancer Research (ICR) mice were randomly divided into five groups of 12 mice, control, vehicle, QLWH (10 and 20 mg/kg) and dexamethasone (DXM), and orally treated twice daily with normal saline, QLWH or DXM. The pneumonia model was established by tracheal instillation of lipopolysaccharide (LPS). After treatment five days, ELISA, H&E staining and Western blot were used to investigate protective effects of QLWH. RESULTS: Nine hundred and ninety-four active ingredients were found through network pharmacology, corresponding to 135 targets for the treatment of pneumonia; compared to the vehicle group, QLWH (10 and 20 mg/kg) significantly decreased the levels of TNF-α (14.3% and 28.8%), IL-1ß (23.9% and 42.8%) and IL-6 (13.2% and 16.1%), increased the levels of IL-10 (134.3% and 172.9%); in terms of mechanism, QLWH down-regulated TLR4/NF-κB/NLRP3 axis related proteins in lung tissue of pneumonia model mice (p < 0.05). DISCUSSION AND CONCLUSIONS: This study combined network pharmacology and animal experiments, providing effective evidence for the clinical promotion of QLWH. Meanwhile, it is of significance for further development.

Synthesis and Study on Ni-Co Phosphite/Activated Carbon Fabric Composited Materials with Controllable Nano-Structure for Hybrid Super-Capacitor Applications.

The advantage of low resistivity and inactive binders makes binder-free electrode an excellent candidate for high-performance energy devices. A simple hydrothermal method was used to fabricate M11(HPO3)8(OH)6 (M: Ni and Co) (MHP) arrays combined with activated carbon fabric (ACF) without binder. The structures of MHP can be easily tuned from bouquets to nano-sheets by the concentration of NaH2PO2. The MHP/ACF composite materials with different structures showed the typical battery-type characteristic of anodic electrodes. In a three-electrode cell configuration, the MHP nano-sheet arrays/ACF composite has a higher capacity, of 1254 F/g, at a scan rate of 10 mA/cm2 and shows better cycling stability: 84.3% remaining specific capacity after 1000 cycles of charge-discharge measurement. The composite is highly flexible, with almost the same electrochemical performance under stretching mode. The MHP/ACF composite@ACF hybrid supercapacitor can deliver the highest energy density, of 34.1 Wh·kg-1, and a power density of 722 W·kg-1 at 1 A·g-1. As indicated by the results, MHP/ACF composite materials are excellent binder-free electrodes, candidates for flexible high-performance hybrid super-capacitor devices.

Y2O3: Eu3+/PMMA hybrid film as a converter for enhanced harvesting of broadband solar-blind UV light.

At present, the most common materials for solar-blind UV light detectors are wide band-gap semiconductors, which generally have high requirements and complex methods for preparation. Ordinary semiconductor materials such as silicon, TiO2, and Cu2O were industrialized, but they were excluded for direct harvest of solar-blind UV light due to their inability to absorb solar-blind light photons. Here, inorganic-organic hybrid film of Y2O3:Eu3+/PMMA was used as a spectral converter to realize the detection of broadband solar-blind UV light by ordinary semiconductor, converting broadband solar-blind UV luminescence to visible luminescence based on down-conversion process, after which the visible luminescence was detected by the Si photo-resister. The results show that hybrid film based on rare earth luminescence materials is particularly valuable for broadband solar-blind UV detection.

Discovery of a novel class of highly potent, selective, ATP-competitive, and orally bioavailable inhibitors of the mammalian target of rapamycin (mTOR).

A series of novel, highly potent, selective, and ATP-competitive mammalian target of rapamycin (mTOR) inhibitors based on a benzoxazepine scaffold have been identified. Lead optimization resulted in the discovery of inhibitors with low nanomolar activity and greater than 1000-fold selectivity over the closely related PI3K kinases. Compound 28 (XL388) inhibited cellular phosphorylation of mTOR complex 1 (p-p70S6K, pS6, and p-4E-BP1) and mTOR complex 2 (pAKT (S473)) substrates. Furthermore, this compound displayed good pharmacokinetics and oral exposure in multiple species with moderate bioavailability. Oral administration of compound 28 to athymic nude mice implanted with human tumor xenografts afforded significant and dose-dependent antitumor activity.

Discovery of XL888: a novel tropane-derived small molecule inhibitor of HSP90.

With structural guidance, tropane-derived HTS hits were modified to optimize for HSP90 inhibition and a desirable in vivo profile. Through an iterative SAR development process 12i (XL888) was discovered and shown to reduce HSP90 client protein content in PD studies. Furthermore, efficacy experiments performed in a NCI-N87 mouse xenograft model demonstrated tumor regression in some dosing regimens.

Discovery of a novel series of potent and orally bioavailable phosphoinositide 3-kinase γ inhibitors.

The phosphoinositide 3-kinases (PI3Ks) have been linked to an extraordinarily diversified group of cellular functions making these enzymes compelling targets for the treatment of disease. A large body of evidence has linked PI3Kγ to the modulation of autoimmune and inflammatory processes making it an intriguing target for drug discovery. Our high-throughput screening (HTS) campaign revealed two hits that were nominated for further optimization studies. The in vitro activity of the first HTS hit, designated as the sulfonylpiperazine scaffold, was optimized utilizing structure-based design. However, nonoptimal pharmacokinetic properties precluded this series from further studies. An overlay of the X-ray structures of the sulfonylpiperazine scaffold and the second HTS hit within their complexes with PI3Kγ revealed a high degree of overlap. This feature was utilized to design a series of hybrid analogues including advanced leads such as 31 with desirable potency, selectivity, and oral bioavailability.

Preparation and the luminescent properties of Tb3+-doped Gd2O3 fluorescent nanofibers via electrospinning.

Tb(3+)-doped Gd(2)O(3) (Gd(2)O(3):Tb(3+)) nanofibers were prepared via a simple electrospinning technique using poly(ethylene oxide) (PEO) and rare-earth acetate tetrahydrates (Ln(CH(3)COO)(3)·4H(2)O (Ln = Gd, Tb)) as precursors. The obtained nanofibers have an average diameter of about 80 nm and are composed of pure cubic Gd(2)O(3) phase. A possible formation mechanism for the nanofibers is proposed on the basis of the experimental results, which reveals that PEO acts as the structure directing template during the whole electrospinning and subsequent calcination process. The luminescent properties of the nanofibers were investigated in detail. The nanofibers exhibit a favorable fluorescent property symbolized by the characteristic green emission (545 nm) resulting from the 5D4-->7F5 transition of Tb(3+). Concentration quenching occurs when the Tb(3+) concentration is 3 at.%, indicating that the Gd(2)O(3):Tb(3+) nanofibers have an optimum luminescent intensity under such a doping concentration.

Desymmetrization of enone-diones via rhodium-catalyzed diastereo- and enantioselective tandem conjugate addition-aldol cyclization.

Catalytic tandem conjugate addition-enolate trapping represents an effective strategy for the design of catalytic transformations that enable formation of multiple C-C bonds. Recently, using enantioselective rhodium-catalyzed conjugate addition methodology, we developed a catalytic tandem conjugate addition-aldol cyclization of keto-enones. Here, we report related desymmetrizations and parallel kinetic resolutions involving the use of diones as terminal electrophiles. The Rh-enolate generated on enone carbometallation effectively discriminates among four diastereotopic pi-faces of the appendant dione, ultimately providing products that embody four contiguous stereocenters, including two adjacent quaternary centers, with quantitative diastereoselection and high levels of enantiomeric excess. This methodology allows concise entry to optically enriched seco-B ring steroids possessing a 14-hydroxy cis-fused C-D ring junction, as found in naturally occurring cardiotonic steroids derived from digitalis.

Diastereoselective cycloreductions and cycloadditions catalyzed by Co(dpm)(2)-silane (dpm = 2,2,6,6-tetramethylheptane-3,5-dionate): mechanism and partitioning of hydrometallative versus anion radical pathways.

In the presence of phenylsilane and 5 mol % cobalt(II) bis(2,2,6,6-tetramethylheptane-3,5-dionate), aryl-substituted monoenone monoaldehydes and bis(enones) undergo reductive cyclization to afford syn-aldol and anti-Michael products, respectively. For both aldol and Michael cycloreductions, five- and six-membered ring formation occurs in good yield with high levels of diastereoselectivity. Cycloreduction of monoenone monoaldehyde 1a in the presence of d(3)-phenylsilane reveals incorporation of a single deuterium at the enone beta-position as an equimolar mixture of epimers, inferring rapid isomerization of the kinetically formed cobalt enolate prior to cyclization. The deuterated product was characterized by single-crystal neutron diffraction analysis. For bis(enone) substrates, modulation of the silane source enables partitioning of the competitive Michael cycloreduction and [2 + 2] cycloaddition manifolds. A study of para-substituted acetophenone-derived bis(enones) reveals that substrate electronic features also direct partitioning of cycloreduction and cycloaddition manifolds. Further mechanistic insight is obtained through examination of the effects of enone geometry on product stereochemistry and electrochemical studies involving cathodic reduction of bis(enone) substrates. The collective experiments reveal competitive enone reduction pathways. Enone hydrometalation produces metallo-enolates en route to aldol and Michael cycloreduction products, that is, products derived from coupling at the alpha-position of the enone. Electron-transfer-mediated enone reduction produces metallo-oxy-pi-allyls en route to [2 + 2] cycloadducts and, under Ni catalysis, homoaldol cycloreduction products, that is, products derived from coupling at the beta-position of the enone. The convergent outcome of the metal-catalyzed and electrochemically induced transformations suggests the proposed oxy-pi-allyl intermediates embody character consistent with the mesomeric metal-complexed anion radicals.

Organocatalytic Michael cycloisomerization of bis(enones): the intramolecular Rauhut-Currier reaction.

The utilization of enones as latent enolates enables regioselective enolate formation from chemically robust presursors. In this communication, we report a catalytic Michael cycloisomerization of bis(enones) under Morita-Baylis-Hillman conditions. Upon exposure to 10 mol % tributylphosphine, bis(enone) substrates afford both five- and six-membered ring products. Notably, unsymmetrical bis(enones) possessing sufficient steric or electronic bias yield single isomeric products.