MiR-221 promotes IgE-mediated activation of mast cells degranulation by PI3K/Akt/PLCγ/Ca2+ pathway

Abstract

Mast cells play a pivotal role in the immediate reaction in asthma. In a previous study, it was found that MicroRNA-221 (miR-221) was associated with asthma. Hence, in the present study, the role and the potential mechanisms of miR-221 on immunoglobulin E (IgE)-mediated activation of mast cells degranulation were investigated. MiR-221 expression was first quantified by qRT-PCR in IgE-mediated activation of mast cells. RBL-2H3 cells were then transfected with miR-221 mimic or miR-221 inhibitor, the IgE-mediated degranulation was detected in mast cells. The influence of miR-221 on expression of phospholipase C gamma (PLCγ1), p-PLCγ1, protein kinase B (Akt), phospho-Akt (p-Akt), inhibitor of kappa B (IκB-α), and phospho-IκB-α (p-IκB-α) were examined by Western blot, whereas free calcium ion (Ca(2+)) level was measured by flow cytometry and NF-κB expression was determined by EMSA. Phosphoinositide 3-kinase (PI3K)-inhibitor (LY294002) and NF-κB-inhibitor [pyrrolidine dithiocarbamate (PDTC)] were used to investigate the role of PI3K/Akt pathway and NF-κB in miR-221 promoting IgE-mediated activation of mast cells degranulation. The expression of miR-221 was upregulated in IgE-mediated activation of mast cells, and it was overexpressed in miR-221 mimic transfected cells. The degranulation was found to be significantly increased in miR-221 overexpressed cells while it was found to be significantly decreased in miR-221 downregulated cells. The expression of p-PLCγ1, p-Akt, p-IκB-α as well as NF-κB and Ca(2+) release were increased in miR-221 overexpressed cells. PI3K-inhibitor (LY294002) could rescue the promotion of degranulation caused by miR-221 in IgE-mediated activation of mast cells. However, NF-κB-inhibitor (PDTC) could not rescue the promotion of degranulation caused by miR-221 in IgE-mediated activation of mast cells. MiR-221 promotes IgE-mediated activation of mast cells degranulation by PI3K/Akt/PLCγ/Ca(2+) signaling pathway, in a non-NF-κB dependent manner.

MicroRNA-200a Affects the Proliferation of Airway Smooth Muscle Cells and Airway Remodeling by Targeting FOXC1 via the PI3K/AKT Signaling Pathway in Ovalbumin-Induced Asthmatic Mice

“…In addition, IL-8 expression has been shown to be regulated by the PI3K/AKT signaling pathway [65]. The PI3K/AKT signaling pathway also plays a key role in the IgE-mediated maturation and activation of mast cells [66,67]. The suppression of the PI3K/AKT signaling pathway has been reported to lead to the inhibition of TNF-α-induced inflammation [68].…”

Long‐term effects: Galectin‐1 and specific immunotherapy for allergic responses in the intestine

“…In sensitized subjects, mast cells are sensitized by binding IgE antibodies. Re‐exposure to specific antigens can activate sensitized mast cells to elicit release of allergic mediators . This study showed that re‐exposure to the specific antigen OVA and levels of serum histamine, the marker of mast cell activation, were significantly increased.…”

“…Immunoglobulin (Ig) E is the major mediator in allergic responses. IgE binds the high‐affinity receptor, FcɛRI, on the surface of mast cells to sensitize them . The sensitized mast cells are activated upon re‐exposure to specific antigens to release chemical mediators that trigger allergic responses .…”

“…IgE binds the high‐affinity receptor, FcɛRI, on the surface of mast cells to sensitize them . The sensitized mast cells are activated upon re‐exposure to specific antigens to release chemical mediators that trigger allergic responses . A number of molecules are capable of preventing mast cell activation, such as cromoglycate; this is a mast cell stabilizer which can prevent its degranulation and inhibit allergic responses .…”

“…The generation of Tregs by SIT may contribute to downregulating expression of IgE, increasing IgG4, and suppressing skewed Th2 polarization . As specific antigens are introduced into the body by SIT, the antigens inevitably bind to the specific IgE/FcɛRI complexes on the surface of mast cells to activate them . The activated mast cells release a number of chemical mediators to regulate immune responses, such as causing Treg dysfunction .…”