Drug repositioning of anti-microbial agent nifuratel to treat mast cell-mediated allergic responses.

Objectives: Our objective was to assess the effects and mechanisms of nifuratel on IgE-mediated mast cell (MC) degranulation and anaphylaxis in both in vitro and in vivo settings.Methods: The anti-allergic activity of nifuratel was evaluated in mast cell cultures and the passive cutaneous anaphylaxis (PCA) model. The effects of nifuratel on signaling pathways stimulated by antigen in mast cells were measured by immunoblotting, immunoprecipitation, in vitro protein tyrosine kinase assay, and other molecular biological methods.Results: Nifuratel reversibly inhibited antigen-induced degranulation of MCs (IC50, approximately 0.34 µM for RBL-2H3 cells; approximately 0.94 µM for BMMCs) and suppressed the secretion of inflammatory cytokines IL-4 (IC50, approximately 0.74 µM) and TNF-α (IC50, approximately 0.48 µM). Mechanism studies showed that nifuratel inhibited the phosphorylation of Syk by antigen via the inhibition of recruitment of cytosolic Syk to the É£ subunit of FcεRI, and decreased the activation of Syk downstream signaling proteins LAT, Akt, and MAPKs. Finally, nifuratel dose-dependently suppressed the IgE-mediated passive cutaneous anaphylaxis in mice (ED50, approximately 22 mg/kg).Conclusion: Our findings suggest that nifuratel inhibits pathways essential for the activation of mast cells to suppress anaphylaxis, thereby indicating that the anti-microbial drug, nifuratel, could be a potential drug candidate for IgE-mediated allergic disorders.

Plasma-Induced Oxygen Vacancies in N-Doped Hollow NiCoPBA Nanocages Derived from Prussian Blue Analogue for Efficient OER in Alkaline Media.

Although water splitting is a promising method to produce clean hydrogen energy, it requires efficient and low-cost catalysts for the oxygen evolution reaction (OER). This study focused on plasma treatment's significance of surface oxygen vacancies in improving OER electrocatalytic activity. For this, we directly grew hollow NiCoPBA nanocages using a Prussian blue analogue (PBA) on nickel foam (NF). The material was treated with N plasma, followed by a thermal reduction process for inducing oxygen vacancies and N doping on the structure of NiCoPBA. These oxygen defects were found to play an essential role as a catalyst center for the OER in enhancing the charge transfer efficiency of NiCoPBA. The N-doped hollow NiCoPBA/NF showed excellent OER performance in an alkaline medium, with a low overpotential of 289 mV at 10 mA cm-2 and a high stability for 24 h. The catalyst also outperformed a commercial RuO2 (350 mV). We believe that using plasma-induced oxygen vacancies with simultaneous N doping will provide a novel insight into the design of low-priced NiCoPBA electrocatalysts.

Entinostat, a histone deacetylase inhibitor, increases the population of IL-10+ regulatory B cells to suppress contact hypersensitivity.

IL-10+ regulatory B (Breg) cells play a vital role in regulating the immune responses in experimental autoimmune encephalomyelitis, colitis, and contact hypersensitivity (CHS). Several stimulants such as lipopolysaccharide (LPS), CD40 ligand, and IL-21 spur the activation and maturation of IL-10+ Breg cells, while the epigenetic mechanism for the IL-10 expression remains largely unknown. It is well accepted that the histone acetylation/ deacetylation is an important mechanism that regulates the expression of IL-10. We found that entinostat, an HDAC inhibitor, stimulated the induction of IL-10+ Breg cells by LPS in vitro and the formation of IL-10+ Breg cells to suppress CHS in vivo. We further demonstrated that entinostat inhibited HDAC1 from binding to the proximal region of the IL-10 expression promoter in splenic B cells, followed by an increase in the binding of NF-κB p65, eventually enhancing the expression of IL-10 in Breg cells. [BMB Reports 2021; 54(10): 534-539].

CD1dhiPD-L1hiCD27+ Regulatory Natural Killer Subset Suppresses Atopic Dermatitis.

Effector and regulatory functions of various leukocytes in allergic diseases have been well reported. Although the role of conventional natural killer (NK) cells has been established, information on its regulatory phenotype and function are very limited. Therefore, the objective of this study was to investigate the phenotype and inhibitory functions of transforming growth factor (TGF)-ß-producing regulatory NK (NKreg) subset in mice with MC903-induced atopic dermatitis (AD). Interestingly, the population of TGF-ß-producing NK cells in peripheral blood monocytes (PBMCs) was decreased in AD patients than in healthy subjects. The number of TGF-ß+ NK subsets was decreased in the spleen or cervical lymph node (cLN), but increased in ear tissues of mice with AD induced by MC903 than those of normal mice. We further observed that TGF-ß+ NK subsets were largely included in CD1dhiPD-L1hiCD27+ NK cell subset. We also found that numbers of ILC2s and TH2 cells were significantly decreased by adoptive transfer of CD1dhiPD-L1hiCD27+ NK subsets. Notably, the ratio of splenic Treg per TH2 was increased by the adoptive transfer of CD1dhiPD-L1hiCD27+ NK cells in mice. Taken together, our findings demonstrate that the TGF-ß-producing CD1dhiPD-L1hiCD27+ NK subset has a previously unrecognized role in suppressing TH2 immunity and ILC2 activation in AD mice, suggesting that the function of TGF-ß-producing NK subset is closely associated with the severity of AD in humans.

Dasatinib Inhibits Lyn and Fyn Src-Family Kinases in Mast Cells to Suppress Type I Hypersensitivity in Mice.

Mast cells (MCs) are systemically distributed and secrete several allergic mediators such as histamine and leukotrienes to cause type I hypersensitivity. Dasatinib is a type of anti-cancer agent and it has also been reported to inhibit human basophils. However, dasatinib has not been reported for its inhibitory effects on MCs or type I hypersensitivity in mice. In this study, we examined the inhibitory effect of dasatinib on MCs and MC-mediated allergic response in vitro and in vivo. in vitro, dasatinib inhibited the degranulation of MCs by antigen stimulation in a dose-dependent manner (IC50, ~34 nM for RBL-2H3 cells; ~52 nM for BMMCs) without any cytotoxicity. It also suppressed the secretion of inflammatory cytokines IL-4 and TNF-α by antigen stimulation. Furthermore, dasatinib inhibited MC-mediated passive cutaneous anaphylaxis (PCA) in mice (ED50, ~29 mg/kg). Notably, dasatinib significantly suppressed the degranulation of MCs in the ear tissue. As the mechanism of its effect, dasatinib inhibited the activation of Syk and Syk-mediated downstream signaling proteins, LAT, PLCγ1, and three typical MAP kinases (Erk1/2, JNK, and p38), which are essential for the activation of MCs. Interestingly, in vitro tyrosine kinase assay, dasatinib directly inhibited the activities of Lyn and Fyn, the upstream tyrosine kinases of Syk in MCs. Taken together, dasatinib suppresses MCs and PCA in vitro and in vivo through the inhibition of Lyn and Fyn Src-family kinases. Therefore, we suggest the possibility of repositioning the anti-cancer drug dasatinib as a treatment for various MC-mediated type I hypersensitive diseases.

WZ3146 inhibits mast cell Lyn and Fyn to reduce IgE-mediated allergic responses in vitro and in vivo.

Mast cells (MCs) play an important role as effector cells that cause allergic responses in allergic diseases. For these reasons, MC is considered an attractive therapeutic target for allergic disease treatment. In this study, we investigated the inhibitory effect of WZ3146, N-[3-[5-chloro-2-[4-(4-methylpiperazin-1-yl)anilino]pyrimidin-4-yl]oxyphenyl]prop-2-enamide, and the mechanisms of its actions on the MC activation and IgE-mediated allergic response by using three types of MCs such as rat basophilic leukemia (RBL)-2H3 cells, mouse bone marrow mast cells (BMMCs), and human Laboratory of Allergic Diseases 2 (LAD2) cells. WZ3146 inhibited antigen-stimulated degranulation in a dose-dependent manner (IC50, ~ 0.35 µM for RBL-2H3 cells; ~ 0.39 µM for BMMCs; ~ 0.41 for LAD2 cells). WZ3146 also suppressed the production of histamine, tumor necrosis factor (TNF)-α and interleukin (IL)-6, which mediate various allergic responses, in a dose-dependent manner. As the mechanism of WZ3146 to inhibit MCs, it inhibited the activation of spleen tyrosine kinase (Syk) and the downstream signaling proteins of Syk such as linker for activation of T cell (LAT) and phospholipase (PL) Cγ1 in the signaling pathway of FcεRI. In addition, WZ3146 inhibited the activation of Akt, extracellular signal-regulated kinase (ERK)1/2, p38, and c-Jun N-terminal kinase (JNK). However, WZ3146 did not inhibit degranulation of MCs by thapsigargin or ionomycin, which increase calcium concentration in cytosol. Notably, WZ3146 inhibited the activity of Lyn and Fyn, but not Syk. In an following animal experiment, WZ3146 inhibited IgE-dependent passive cutaneous anaphylaxis (PCA) in a dose-dependent manner (ED50, ~ 20 mg/kg). Taken together, in this study we show that the pyrimidine derivative, WZ3146, inhibits the IgE-mediated allergic response by inhibiting Lyn and Fyn Src-family kinases, which are initially activated by antigen stimulation in MCs. Therefore, we propose that WZ3146 could be used as a new therapeutic agent for the treatment of allergic diseases.

Copper-catalyzed addition of diboron reagents to alpha,beta-acetylenic esters: efficient synthesis of beta-boryl-alpha,beta-ethylenic esters.

The efficient copper-catalyzed addition reaction of bis(pinacolato)diboron to alpha,beta-acetylenic esters has been developed, which produces the corresponding beta-borylated-alpha,beta-ethylenic esters in high yields under mild reaction conditions.

Copper-catalyzed beta-Boration of alpha,beta-unsaturated carbonyl compounds: rate acceleration by alcohol additives.

[reaction: see text] The efficient addition of bis(pinacolato)diboron to alpha,beta-unsaturated carbonyl compounds with a copper-diphosphine catalyst has been carried out. A dramatic rate acceleration of the reaction was realized by adding alcohol additives. With use of this procedure, a variety of alpha,beta-unsaturated carbonyl compounds including conjugated substrates at the acid oxidation level such as esters and nitriles were reacted to give to the corresponding beta-boryl carbonyl compounds in high yields.