dehydroandrographolide and Disease-Models--Animal

Mas-related G protein-coupled receptor X2 (MRGPRX2) mediates mast cells (MCs) activation, which is a key target for the treatment of allergic diseases. However, there are few drugs targeting MRGPRX2. Leukocyte mono-immunoglobulin-like receptor 3 (CD300f) is a negative regulator of FcεRΙ-mediated MC activation. However, the regulatory effect of CD300f on MRGPRX2 remains unclear. Dehydroandrographolide (DA) is a main contributor of Andrographis paniculata (Burm.f.) Nees (family: Acanthaceae) have been shown to inhibit type I hypersensitivity. The aim of this study was to determine whether DA negatively regulated MRGPRX2-mediated MC activation via CD300f and showed therapeutic effect on pseudo-allergic reactions. Mouse allergic models and MC degranulation were detected in vivo and in vitro, and inflammatory mediators were detected. siRNA interference and Biacore were used to verify the target. DA inhibited pseudo-allergic reactions by reducing vasodilation and serum cytokine levels in mice and inhibited MRGPRX2-mediated MC activation. The regulatory effect of DA was significantly decreased after the knockdown of CD300f expression. Moreover, DA upregulated the phosphorylation level of Src homology region 2 domain-containing phosphatase (SHP)-1 and SHP-2, which are key kinases in the negative regulatory signaling pathways associated with CD300f. In conclusion, DA negatively regulates MRGPRX2-mediated MC activation via CD300f to inhibit pseudo-allergic reactions.

Topics: Animals; Cell Degranulation; Disease Models, Animal; Diterpenes; Hypersensitivity; Mast Cells; Mice; Mice, Inbred C57BL; Receptors, G-Protein-Coupled

The classical mast cells degranulation pathway is mediated by FcεRI aggregation and varies in strength among subjects. Dehydroandrographolide (DA) is one of principal components of Andrographis paniculata (Burm.f.) Nees (family: Acanthaceae) and considered the main contributors of its therapeutic properties, such as anti-tumor. In this study, inhibition of IgE-mediated anaphylactic reactions and anti-inflammatory potential of DA were investigated. The anti-anaphylactic activity of DA was investigated using skin swelling and extravasation assays in vivo and mast cell degranulation assay in vitro. The release of cytokines was measured using ELISA kits. Human Phospho-Kinase Array kit and western blotting were used to explore the related molecular signaling pathways. DA inhibited IgE-mediated mast cell activation, including degranulation and release of cytokines in vitro. Moreover, DA reduced the degree of swelling and Evans blue exudation of mice paw in a dose-dependent manner by inhibiting mast cell degranulation. DA obviously reduced the concentrations of histamine, TNF-α, MCP-1, IL-8, IL-13, and IL-4 in mice serum and inhibited IgE-mediated anaphylactic reactions as a potential P-PLCγ inhibitor. Our study reveals that DA can inhibit allergic responses in vivo and in vitro, and it may be regarded as a novel P-PLCγ inhibitor for preventing mast cell-immediate and delayed allergic diseases.

Topics: Anaphylaxis; Animals; Anti-Allergic Agents; Calcium Signaling; Cell Degranulation; Cell Line; Cytokines; Disease Models, Animal; Diterpenes; Enzyme Inhibitors; Histamine Release; Humans; Immunoglobulin E; Male; Mast Cells; Mice, Inbred C57BL; Ovalbumin; Phospholipase C gamma