LY333531 attenuates contraction of tumor necrosis factor-α-sensitized human airway smooth muscle cells

Abstract

Objective: Protein kinase C (PKC) has been implicated in the increased contraction of human airway smooth muscle cells (HASMCs) in asthma. Using the three-dimensional collagen gel contraction system, the study aimed to determine the effects of LY333531, a specific inhibitor of the PKC-β isoform, on the contraction of tumor necrosis factor (TNF)-α-sensitized HASMCs.

Methods: Cultured HASMCs were divided into five groups: the control group received no treatment, and the cells in the TNF-α group were sensitized with 10 ng/mL TNF-α for 48 hours, while TNF-α was administered to sensitize HASMCs in the presence of 0.1 μM, 0.2 μM, and 0.5 μM LY333531 for 48 hours in the 0.1LY, 0.2LY, and 0.5LY groups, respectively. Following this, HASMCs contraction were stimulated with 1 mM acetylcholine (ACh) for up to 24 h in each group and assessed using a three-dimensional collagen gel contraction assay. Furthermore, western blot and immunofluorescence analysis were performed.

Results: The collagen gel contraction assay revealed that TNF-α increased the protein expression of phosphorylated PKC-β2, CPI-17 and MLC, while exacerbating ACh-induced HASMCs contraction. LY333531 significantly attenuated HASMCs contraction and downregulated the protein expression of both p-CPI-17 and p-MLC.

Conclusions: At least in part by regulating CPI-17 and MLC phosphorylation, LY333531 attenuates augmented contraction of TNF-α-sensitized HASMCs in a collagen gel contraction system.

Keywords:

• airway hyperreactivity
• asthma
• CPI-17
• protein kinase C
• tumor necrosis factor-α

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