Calcitonin gene-related peptide inhibits interleukin-1 β-induced interleukin-8 secretion in human type II alveolar epithelial cells
Authors: LI, Wen-jing; WANG, Teng-ke; WANG, Xian
Source: Acta Pharmacologica Sinica, Volume 27, Number 10, October 2006 , pp. 1340-1345(6)
Abstract:Aim: Our previous data have shown that type II alveolar epithelial (AEII) cells express neuropeptide calcitonin gene-related peptide (CGRP), and that pro-inflammatory factor interleukin1-β (IL-1β) induces CGRP secretion in the A549 human AEII cell line. In the present study, we investigated the effect of endogenous and exogenous CGRP on IL-1β-induced chemokine interleukin-8 (IL-8) secretion. Methods: We used enzyme-linked immunosorbent assay (ELISA) and RT-PCRto detect IL-8 protein and mRNA levels, respectively. siRNA and the stably trans-fected cell line were used to knock down and overexpress the CGRP gene, respectively, and chemiluminescence assay was used to detect reactive oxygen species (ROS) formation. Results: CGRP-1 receptor antagonist hCGRP8-37 (0.1-1 nmol-L−1) greatly amplified IL-1 β-induced IL-8 production. The inhibition of CGRP expression by siRNA significantly increased IL-8 secretion upon IL-1β stimulation. However, cell clones stably transfected with CGRP showed significantly inhibited mRNAandproteinlevelsofIL-8 inducedbyIL-1β. Conclusion: These data imply that AEII cell-derived CGRP suppress IL-1 β-induced IL-8 secretion in an autocrine/paracrine mode. Further investigation showed that CGRP attenuated IL-1 β-aroused ROS formation, which is an early indication of pro-inflammatory factor signaling.
Document Type: Research article
Publication date: 2006-10-01